Paint can be applied to almost any kind of object. It is used in the production of art, in industrial coating, as a driving aid (road surface marking), or as a barrier to prevent corrosion or water damage. Quality control for paint product can be achieved through conducting a number of physical and chemical tests to paint samples. In the paint and coating industries, paint testing is often used to determine if the paint or coating will adhere properly to the substrates to which they are applied. Testing of paint, varnishes and resins can be done in a number of different ways. The fact of the matter is that many industries use several different paint testing methods in order to ensure accurate results. Products of the surface coating are essential for the preservation of all types of architectural structures, including factories, from ordinary attacks of weather, micro and macro organisms, atmospheric pollutant, etc. Architectural coatings are usually applied to wood, gypsum wall board, or plaster surfaces. Bituminous coatings are used on surfaces to reduce or eliminate the destructive effects of weather, chemicals and water vapour. They are also used as sound deadeners, to provide resistance to heat transfer and to provide abrasive coatings to minimize slip hazards. Traffic paint is an important factor in the control of traffic, not only of motor vehicles but also of aircraft at airports and of pedestrian traffic. Proper paint formulations depend upon raw materials selection and accurate calculation of the amounts of its constituents. Therefore it becomes necessary to adopt various test methods for testing the quality of product. The final product shall have no adverse effect on the health of personnel when used for its intended purpose and applied in approved facilities with the use of approved safety equipment.
This testing manual elaborates the methods used to determine the physical and chemical properties of paint, varnish, resins, and related materials. Some of the fundamentals of the book are biological deterioration of paints and paint films, weathering tests natural weathering, artificial weathering machines, new jersey zinc company machine, gardener parks wheel, atlas weather Ometer, sunshine carbon arc weather Ometer, British railways machine, British paint research station machine, waxes and polishes, putty, glazing compounds, caulking, compound and sealants, tile like coatings, applicable specifications, adhesion tests, Evans adhesion test, resistance to alkaline peeling (Evans method), paint for electrocoating, synthetic resins, driers and metallic soaps, natural resins
The purpose of this book is to help its readers to establish standardized testing methodologies and to eliminate unnecessary or undesirable variations in test results when evaluating a products adherence to specification requirements. It is hoped that this book will help its readers who are new to this sector and will also find resourceful for new entrepreneurs, existing industries, technical institution etc.
1. BIOLOGICAL DETERIORATION OF PAINTS AND PAINT FILMS
Description of the Problem, Microorganisms Associated with Paint, Growth Structures of Fungi, Chemical Methods for Fungal Identification, Antimicrobial Agents, Determining Microbiological Resist¬ance of Paints, Bacterial Resistance of Liquid Paints, Measuring the Fungal Resistance of Paint Films, Insect-Resistant Paints
2. WEATHERING TESTS NATURAL WEATHERING
Introduction, Effect of Climate, Test Racks, Offset-Rack, Angle of Exposure, Follow-the-Sun Racks, Application of Paints, Tests on Wood, Number of Specimens, Tests on Iron and Steel, Substrates, Cleanliness of Surfaces, Pictorial Standards for Steel Sur¬faces to be Painted, Manual Scraping and Wire Brushing , Blast Cleaning, Specifications of Steel Structures Painting Council for Preparation of Surfaces, Tests on Galvanized Steel, Tests on Aluminum, Tests on Magnesium, Tests on Masonry, Evaluating Weathering Tests, Gloss, Chalking, and Erosion, Checking and Cracking, Flaking, Scaling, and Peeling, Integrity Protection, Dirt and Mold (mildew), Rust and Metal Stain, Color Retention (fading, darkening, and yellowing), Moisture Blistering of Paint on Wood, Detecting Rainfall and Dew, “Washing” of Paints, Recording Weathering Tests, Scheifele Summary, Nomographs for Rating Weathering,
3. ARTIFICIAL WEATHERING
Introduction, Artificial Weathering Machines, New Jersey Zinc Company Machine, Gardner-Parks Wheel, Atlas Weather-Ometer, “Snushine” Carbon Arc Weather Ometer, British Railways Machine, British Paint Research Station Machine, British Standards Institution Test, ABEM IV Machine, Dew Weather-Ometer, Fluorescent Ultraviolet Light Sources, ASTM Artificial Weathering Procedures, Actinic Values, Intensified Tests, Photochemical Embrittlement Test, Ozonization Test, Lightfastness of Pigments, Thin Substrates Corrosion Test, High Frequency Tide Range Test, Sudden Chill Test
4. ATMOSPHERIC POLLUITANTS
Source of Pollutants, Regulations, Analytical Methods, Smog Chambers
5. SPECIFIC PRODUCTS TESTS ON VARNISHES
Introduction, Test on Liquid Varnish, Appearance, Color, Viscosity, Viscosity Control During Manufacture, Nonvolatile Content, General Method, Method Flash Point A, Resin Solutions, Density (specific gravity), Elasticity (toughness), Linseed Oil Addition, Predicting Kauri Reduction, Leafing Test, Spatula Test, Beaker Test, Skinning, Reactivity, Acid Value, Alkali Increase Test, ASTM Reactivity Test, Rosin Content, Drying Time, Tests on Dry Films, Film Irregularities, Bell Jar Test, Oven (cabinet test), Smokey Joe Oven, Rogers Test, Draft Test, Resistance to Selflifting, Rubbing Property, Hardness and Abrasion Resistance, Plasticizer Migration, Temperature Change Resistance (cold check test), Tests on Clear Floor Sealers, Specimens, Appearance, Resistance to Ink Stain, Restoration of Worn Areas, Finishing with Other Coatings, Tests on Shellac Varnish, Color, Drying Time, Nonvolatile Content
6. ARCHITECTURAL PAINT
Introduction, Conditions Affecting Use of Paint, Exterior Point, lnterior Paint, Liquid Paint, Condition in Container, Skinning, Settling, Curds, Agglomerates, and the Like, Coarse Particles, Fineness of Dispersion, Density, Flash Point, Dilution Stability, Consistency (Viscosity, Rheological Proptirties), Working Properties, Brushing Properties, Wet-Edge Time, Spraying Properties, Rolling Properties, Absorption and Holdout, Subjective Test, Vehicle Migration Test, Stain Test, Freeze Thaw Stability , General Method, Special Method for Multicolor Lacquer, Resistance to Microorganisms, Color Acceptance, Drying
Time, Test on Dry Film, Appearance, Adhesion, Elongation, Moisture Blister Resistance, Fume Resistance, Efflorescence from Interior Latex Paint, Resistance to Fungi, Washability, Scrub Resistance, Stain Resistance, Fading, Yellowness Index
7. CEMENT BASE PAINT AND THE PAINTING OF MASONARY
Introduction, Typical Properties of Portland Cement, Tests on Dry Powder, Color, Coarse Particles, Oil Absorption, Set Time, Performance Tests of Cement-Base Coatings, Sentel Studies, ASTM Concrete and Masonry Panels, Federal Concrete Panels, Alkali Resistance of Coatings Concrete, Wet Feet Test for Concrete Paint, Croll-Rhue Plaster Cup Test, Efflorescence Resistance of Masonry Paints, Waterproofing, Ready-for-Paint Stage of Masonry
8. WAXES AND POLISHES
Introduction, Tests on Raw Materials, Melting Point, Specific Gravity, Acid Value, Saponification Value, Crystallinity of Petroleum Waxes, Paraffin Hydrocarbons in Carnauba Wax, Detection of Glycerides, Detection of Stearic Acid, Detection of Rosin, Tests on Liquid Polishes, Nonvolatile Matter in Emulsion Polish, Nonvolatile Matter in Solvent-Type Waxes, Ash, Silica, and Sulfur, Sediment, Stability of Emulsion-Type Waxes , Stability of Solvent-Type Wax , pH of Emulsion Wax, Abrasive Matter, Test on Films, Preparing Test -Films of Emulsion Floor Polishes, Drying Time, Water Spoiling, Gloss, Removability, Powdering, Metal-Glide Adhesion Test, Softening of Tile Substrate, Subjective Method, Objective Method, Slip Resistance, Practical Field Tests
9. PUTTY, GLAZING COMPOUNDS, CAULKING,
COMPOUND AND SEALANTS
Introduction, Definitions, Working Properties, Subjective Test for Knife Compounds, Cone Penetrometer for Consistency, Mobilometer for Consistency, Sandwich Squeeze for Consistency, Brookfield Viscometer for Consistency, Extrudability with Caulking Gun, Extrusion Rhcometer, Shearing Adhesiveness, Rheological Properties, Leveling Test, Sag (slump) Test, Tack-Free Time, Shrinkage, Apparatus, Procedure, Cohesiveness, Tensile Adhesiveness (cohesion), Tenacity, Bend Test, Low Temperature Flexibility, Adhesion, Bond Strength by Direct Pull, ASTM Method for Bond Strength, Shear Method for Bond Strength , Peel Method for Bond Strength, Bend Test for Adhesion, Gravity Test for Adhesion, Impact Test for Adhesion, Hardness, Durometer Hardness under Standard Conditions, Durometer Hardness After Heat Aging, Penetrometer for Hardness, Penetrometer for Degree of Set, Compression Set, Aging Tests on Caulks and Sealants, Heat Aging Tests, Artificial Weathering Tests, Oxygen Bomb Aging Test, Stain Tests, Filter Paper Stain Test, Practical Stain Test on Masonry, Accelerated Stain Test, Stain from Back-Up Material, Stability, Chemical Analysis.
10. TILE LIKE COATINGS AND SEAMLESS FLOOR
Introduction, Tile-like Coatings, Applicable Specifications, Adhesion Tests, Evans Adhesion Test, Resistance to Alkaline Peeling (Evans Method), Dowel Test for Adhesion, Elcometer Test for Adhesion, Ability to Smooth Concrete Block, Gloss Readings on Rough Surfaces, Smoothness (holdout), Color Retention, Effect of High Humidity on Color Retention, Fungus Resistance, Stain and Chemical Resistance: Washability, Staining, Ease of Soil Removal , Scrubbability, Abrasion Resistance, and Hardness, Abrasion Resistance, Impact Test, Hardness, Seamless Floor Testing, Introduction, Test Specimens, Tests and Test Methods, Appearance Factors, Resistance Factors, Physical Properties, Adaptability to Existing Floor Surfaces
11. BITUMINOUS COATINGS
Definitions, Identification of Bituminous Materials, Solubility in Carbon Disulfide, Differentiating Asphalt and Coal Tar, Oliensis Spot Test, Tests on Solid and Semisolid Bituminous Materials, Penetration, Softening Point, Ductility, Softening Point Drift and Flow, Oliensis Contact Compatibility Test, Tests on Solvent-Thinned Cut-Back Coatings, Uniformity, Consistency, Flash Point, Nonvolatile Content, Distillation, Water Content, Asphalt Content, Filler Content, Aluminum Content of Roof Coatings, Roof Coatings Setting Test, Application, Blistering and Sagging, Flexibility Test, Reflectance of Aluminized Roof Coating, Tests on Emulsions, Uniformity and Stability, Nonvolatile Content , Ash, Water, Application Properties, Wet Flow, Setting Characteristics , Heat Test, Flexibility Test, Water Resistance, Alternate A, Alternate B, Stability, Flame Test, Flamability
12. TRAFFIC PAINT
Introduction, Stability and Settling Properties, Tests on Glass Beads, Crushing Test, Roundness Test,
Sieve Analysis, Surface Moisture, Chemical Resistance, No-Pick-Up Time, Flexibility, Night Visibility, Nelson- Werthan Illuminometer, Hunter Night Visibility Meter, Hill-Ecker Photometer, Photographic Method, Resistance to Abrasion, Hickson Traffic Paint Abrasion Tester, Payne Abrasion Machine, Abradometer, Dorry Abrasion Tester, New Jersey Zinc Company (NJZ) Abrasion Tester, Resistance to Bleeding, Water Resistance, Accelerated Weathering, Road Tests, Detecting Adulteration of Traffic Paint, Bean-Chaiken Method, Procedure, ASTM Recommended Practices
13. PAINT FOR MARINE ENVIRONMENT
Atmospheric Marine Panel Exposure Tests, Tide Range Exposure Tests, Ship Bottom Patch Test, Canadian Navy Evaluation of Ship Bottom Coatings, Testing Antifouling Paints, Template Inspection Aid, Metallic Copper in Antifouling Paints, Leaching Rates of Antifouling Paints, Examination of Antifouling Coatings by Electron Microscopy, Testing Cathodic Protection, Rotor Apparatus,
14. PAINT FOR ELECTROCOATING
General Principles, Quality Tests, Test Panels, Nonvolatile Content of Electro coating Bath, Hydrogen Ion Concentration and Titratable Alkalinity, Ash-Binder Ratio in Electrocoating Paint, Preparation of Electrocoated Test Panels, Throwing- Power of Electrocoating Paint, Pumping Stability of Electro-coating Paints, Procedure, Current Requirements for the Electrocoating Process, Control and Testing of Feed Materials, Laboratory Electrocoaters, Glidden Laboratory Electrocoater, Ford Laboratory Strip Coater
15. ANALYSIS OF WHOLE PAINT
Sampling, Separations and identification of Binder and Solvent, Sampling, General Precautions and Suggestions, Procedure, Preliminary Tests on Whole Faint, Nonvolatile Content by Weight, Nonvolatile Content by Volume, Pigment Content, Water Content, Flash Point, Separation of Pigment, Separation of Vehicle, Identification of Binder, Solvent Based Paints and Lacquers, Water Based Paints, Separation of Solvent, Identification of Solvent
16. CHEMICAL ANALYSIS OF PIGMENTS
Sampling, Purity of Reagents and Water, Some Common Properties, Moisture Content, Loss on Ignition and Ash, Matter Soluble in Water, Hydrogen Ion Concentration, Alkalinity or
Acidity, Single White Pigments, Titanium Dioxide and Titanium-Calcium, Titanium, Alumina, Silica, Lead, Carbon Dioxide, Carbon Dioxide and Combined Water, Lead Carbonate, Matter insoluble in Acetic Acid, Impurities Other Than Moisture, Sulfate, Basic Lead Oxide, Impurities, Basic Silicate White Lead, Tribasic Lead Phosphosilicate, Moisture, Water of Hydration, Silica, Lead, Phosphorus as P2O5, Zinc, Sulfur, Lead, Zinc, Sulfur, Zinc Oxide, Zinc Sulfide, Barium Sulfate, Titanium Dioxide, Antimony Oxide, Antimonous Oxide, Total Oxide, Matter Soluble in Hydrochloric Acid, Silica, Aluminum Oxide, Alumina and Iron Oxide, Calcium Oxide, Magnesium Oxide, Mica, Calcium Carbonate, Calcium Oxide, Calcium Sulfate, Free Water, Combined Water, Matter Insoluble in HCI, Barium Sulfate, Ferric Oxide, Free Silica, Mixed White Pigments Extracted from Paint, Moisture, Loss on Ignition, Acidity or Alkalinity, Matter Insoluble in Hydrochloric Acid, Total Lead, Lead Titanate, Aluminum Oxide, Zinc Oxide, Soluble Barium, Calcium, Magnesium, Total Soluble Sulfur, Sulfide Sulfure, Carbon Dioxide, Soluble Sulfate, Sulfur Dioxide, Black Pigments, Bone Black, Carbon Black, and Lampblack, Identification, Acetone Extract, Carbon and Insoluble Mineral Matter, Synthetic Black Iron Oxide, Identification Ferrous Iron Oxide, Metallic Pigments, Aluminum, Qualitative Analysis, Fatty and Oily Matter, Metallic Zinc, Zinc Oxide, Calcium as Calcium Oxide, Lead Cadmium, and Iron, Chlorine, Sulfur, Blue pigments, Iron Blue, Identification, Moisture, Water-Soluble Matter, Acid Insoluble Extenders, Acid-soluble Extenders, Organic Colors
and Lakes, Copper Phthalocyanine Blue, Identification, Basic Dye Derivatives, Other Organic Coloring Matter, Ultramarine Blue, Iron Blue, Yellow, orange, and green pigments containing lead chromate and chromium oxide green, Chrome Yellow, Chrome Orange, and Molybdate Orange, Preparation of Samples, Lead Chromate, Total Lead, Total Sulfate, Molybdenum, Extenders, Lead, Chromium Trioxide, Silica, Lead Chromate, Barium Sulfute and Insoluble Siliceous Material, Sulfate, Calcium Oxide, Yellow, orange, and brown pigments containing strontium chromate and zinc chromate, Strontium Chromate, Moisture and Other Volatile Matter Strontium, Chromium, Chloride, Sulfate, Zinc Yellow (zinc chromate yellow), Combined Water, Aliquots for Tests, Chromium, Alkaline Salts, Matter Insoluble in Acetic Acid, Yellow, orange, red, and brown pigments containing iron and manganese, Iron Oxide, Calcium Compounds, Calcium Carbonate (in Venetian Red), Sulfates Soluble in Hydrochloric Acid, Qualitative Test for Lead Chromate in Ochre, Manganese (in sienna and umber), Other red pigments, Cuprous Oxide (antifouling) and Other Copper Pigments, Special Precautions for Sample Treatment, Total Copper, Total Reducing Power as Cuprous Oxide, Metallic Copper, Cuprous Oxide, Cupric Oxide, Metals Other than Copper, Chlorides and Sulfates, Acetone-Soluble Matter, Dry Red Lead, Total Lead and Insoluble Matter, Lead Peroxide and True Red Lead, Zinc, Total Silica, Carbon Dioxide, Soluble Sulfate (other than barium sulfate), Iron Oxide, Dry Mercuric Oxide Ash, Free Mercury, Total Mercury, Organic Pigments and Colorants, Solubility in Chloroform, Qualitative Test for Identity and Purity, Resistance to Acids and Alkalis, Henlein Color Identification Chart
17. SYNTHETIC RESINS
General Methods of Resin Identification, Chemical Methods, Spectrometric Methods, Alkyd and Polyester Resins, Identification by Chemical Methods, Identification by Spectrometric Methods, Carboxylic Acids, Phthalic anhydride, Procedure, Reagents, Modification for Lacquers, Gas-Liquid Chromatographic Method-, Equipment and Conditions, Reagent, Procedure, Isophthalic, terephthalic, and benzoic acids, Chlorendic acid, Apparatus, Reagents, Maleic, adipic, and other acids in polyesters, Equipment and Conditions, Reagents, Fatty Acids, Polyhydric Alcohols, Rosin and Ester Gum Modified Alkyd, Styrene-Modified Alkyds, Equipment and Conditions, Urea-Formaldehyde (UF) Modified Alkyds, Apparatus, Calculation—UF in Alkyd-UF-MF Blends, Calculation—Phthalic Anhydride Content, MF and BF Modified Alkyds, Other Resin Modifications, Gibb’s Test, Nitrite Test, Para-phenylphenol-Formaldehyde Test, Procedure, Spectrometric Determination of Phthalate, Other Analytical Tests, Cellulosic Resins, Classification, Identification by Chemical Methods, Griess Reagent, Identification by Infrared Spectrometry, Quantitative Methods for Cellulose Ethers, Quantitative Methods for Cellulose Esters, Quantitative Methods for Cellulose Nitrate, Nitrogen Resins, Detection and Differentiation, Identification of Melamine- and Benzoguanamine-Formaldehyde, Determination of Melamine, Determination of Benzoguanamine, ldentification of Urea-Formalde-hyde, Urea Content, Methylol and Dimethylol Urea-Formaldehyde Content, Ethylene Urea-Formaldehyde Content, Thiourea Content, Acrylnitrile, Free Acrylonitrile Monomer Content, Polyacrylonitrile Content, Analysis of Copolymers of Acrylonitrile, Polyamide Content, Reagent, Polyurethane Resins, Other Nitrogen Polymers, Phenol-Formaldehyde and Epoxy Resins, Spectrophotometric Identification of Phenolic Resins, Quantitative Methods for Phenolic Resins, Chemical Methods for Identifying Epoxy Resins, Spectrophotometric Identification of Epoxy Resins, Quantitative Analysis of Epoxy Resins, Analysis of Curing Agents for Epoxy Resins, Silicone Resins, Chemical Examination, Spectrometric Examination, Special Methods, Vinyl Resins, Qualitative Methods, Quantitative Methods, Acrylic Resins, Identification by Infrared Techniques, Identification by Gas-Liquid tography, Determination of Monomer, Quantitative Methods for the Polymer
18. RAW MATERIAL
Drying Oils, Cacahuananche Oil, Castor Oil, Chia Oil, Corn Oil, Cottonseed Oil, Hempseed Oil, Linseed Oil, Lumbang Oil, Oitictca Oil, Perilla Oil, Poppyseed Oil, Rapeseed Oil, Safflower Oil, Soybean Oil, Sunflower Oil, Tung Oil, Sampling, Notes on Reagents for Chemical Tests, Acid Value, ASTM Method, Diener-Werthan Method, Method for Dark Oils, Potentiometric Method, Method for Films, Saponification Value, Potentiometric Method, Double Indicator Method, Unsaponifiable Matter, Unsaturation, Wijs Iodine Value, Roseninund-Ktihnhenn Method, Apparatus, Reagents, Hexabromide Test for Underlie Acid, Reagents, Kaufmann Thiocyanate Value, Calculations, Conjugated Diene Value, Reagents and Solvents, Ash, Foots, Volumetric Test, Reagents and Apparatus, Gravimetric Method, Reagents and Apparatus, Carbon Tetrachloride, Specific Gravity, Refractive Index, Optical Dispersion Test for Tung Oil, Viscosity, Relation of Refractive Index to Viscosity and Molecular Weight, Clarity, Color, Flash Point, Loss On Heating, Moisture by Karl Fischer Method, Reagents and Calibration, Procedure, Chloroform-Insoluble Matter, Hydroxyl Value, Reagents, Heat Bodying Rate, Acetone Tolerance, Heat Bleach, Oxygen Content of Blown Oils, Peroxide Value, Drying Properties, Gelation Tests, Browne Heal Test, Worstall Quality Test, Bolton Test for Tung OH, Miscellaneous Tests for Tung Oil, Detection of Boiled Linseed Oil, Determining Dimers and Trimers in Bodied Oil, Detection of Fish Oils and Paints, Blinker Test for Oils and Resins, Chromatographic Methods, Poxon Chromatogram
19. DRIERS AND METALLIC SOAPS
Introduction, Physical Tests on Driers, Appearance, Color, Miscibility, Drying Power, Flash Paint , Specific Gravity, Viscosity , Stability, Chemical Analysis, Metal Separation by Ashing, Metal Separation with Hydrochloric Acid , Metal Separation as Acetate, Metal Separation as Oxalate , Determination of Lead, Determination of Manganese, Determination of Cobalt, Determination of Zinc, Determination of Iron, Chelometric Determination of Drier Metals, Lucchesi Method, Solutions, Procedure for Calcium, Cobalt, and Zinc, Procedures for Lead and Manganese, Graske Method, Computations, ASTM D 2373, EDTA Method for Cobalt, ASTM D 2374, EDTA Method for Lead, ASTM D 2375, EDTA Method for Manganese, ASTM D 2613, EDTA Method for Calcium or Zinc, Tests on Metallic Soaps, Mallinckrodt Gel Test, Licata Gel Test
20. NATURAL RESINS
Classifications, Identification of Natural Resins, Identification of Rosin, Identification of Lac, Commercial Grades of Natural Resins, Manila (Macassar) Spirit Soluble , Manila (Philippine) Spirit Soluble, Manila (Singapore) , Congo (American Gum Importers Classification), Refractive Index, Hardness, Softening Point, Capillary Tube Method, Ring and Bull Method, Preparation of Sample, Durrans Method, Wilter Method, Paramet Method, Drip Method, Density, Bulking Value, Solubility, Nonvolatile Content of Resin Solutions, Dirt in Resins, Volumetric Method for Dirt, Gravimetric Method for Din, Ash Content, Moisture Content, Acid Value, Reserve the specimen for the indirect acid value, AGI Indirect Acid Value, AGI Saponification Value, Rosin, Sampling and Grading Rosin, Sampling Rosin, Color of Rosin, Softening Point of Rosin, Dirt in Rosin, Toluene Insoluble Matter, Georgi Photographic Method, Ash in Rosin, Iron Content, Spectrophoto-metric Procedure, Visual Photometric Procedure, Acid Value, Saponification Value of Rosin, Unsaponifiable Matter in Rosin, ASTM Method D 1065, Volatile Oils, Fatty Acids Content of Tall Oil Rosin, Viscosity, Pour Point, Ash, Acid Value, Saponification Value, Unsaponiflable Matter, Rosin Acids, Fatty Acids, Lac, Insoluble Matter in Lac, Extraction Method,
Hot Filtration Method, Iodine Value, Purity, Detection of Rosin, Detection of Copal, Estimating Adulteration, Wolff Method for Rosin in Shellac, Volatile Matter (moisture), Matter Soluble in Water, Acid Value, Saponification Value, Orpiment, Color, General Comparison Method, Color Index
Cellulose Nitrate, Viscosity Grade, Solubility and Appearance of Solution, Film Test, Toluene Dilution Ratio, Cellulose Nitrate Base Solutions, Viscosity, Nonvolatile Content, Appearance, Cellulose Acetate, Viscosity, Color and Haze, Solubility and Appearance of Solution, Cellulose Acetate-Butyratce and Cellulose Acetate-Propionate, Ethylcellulose, Viscosity, Methylcellulose, Viscosity of Water-Soluble Methylcellulose, Viscosity of Alkali-Soluble Methylcellulose, Sodium Carboxymethylcellulose, Viscosity, Hydroxyethylcellulose, Hydroxypropyl Methylcellulose, Viscosity, Hydrogen Ion Concentration, Solids
Introduction, Physical and Chemical Test Methods, Acidity, Color, Compatibility, Copper Corrosion, Distillation Range, Electrical Properties, Ester Value, Flash Point, Refractive Index, Residual Odor, Sampling, Solidification Point, Specific Gravity, Viscosity, Water, Chemical Methods of Identification and Measurement, Isolation of Plasticizer, Qualitative Methods, Quantitative Methods, Instrumental Methods, Identifications by Refractive Index and Density, Fluorescence, Spectrophotometry, Chromatography
Definition and Requirements, Solvency, Solubility Parameter System, Viscosity Reduction, Aniline Point, Kauri-Butanol Value, Dilution Ratio, Dilution Limit, Evaporation (volatility), Vapor Pressure, Evaporation Rates by Electrobalance, Butyl Acetate Evaporation Standard, Historical Evaporation Rate Methods, Evaporation of Solvent from Coatings, Solvent Retention by Films, Distillation Temperature, McArdle-Robertson Evaporation Index, Analytical Distillation, Flash Point, Composition, Chromatography, Liquid Chromatography, Acid Absorption and Bromine Number Methods, Refractively Intercept, Ester Value of Lacquer Thinners, Physical Properties, Density and Specific Gravity, , Refractive Index, Purity and Impurities, Color, Acid Wash Color, Odor, Sulfur Compounds, Nonvolatile Residue, Water Contamination, Acidity and Alkalinity, Other Contaminants, Specifications, Systematic Identification and Analysis
BIOLOGICAL DETERIORATION OF PAINTS AND PAINT FILMS
Description of the Problem
macro organisms can destroy both the
decorative properties and durabilities of paint films. Bio
paint falls into two general categories: enzymatic degradation of
cellulosic thickeners that produces an irreversible viscosity loss in
emulsion paints while still in the container, and microbial
deterioration of both water thinned and solvent thinned paint films.
the degradation of protein and cellulosic thickeners may be introduced
paint through contaminated raw materials, storage tanks, and other
be released by bacteria (and less frequently, yeast) growing actively
The susceptibility of paint films to
attack by micro organisms is determined in part by the chemical nature
nonvolatile binder, the choice of pigmentation, and the pigment volume
concentration. To a much greater degree however, the susceptibility or
resistance of a paint film to biological attack is determined by the
and concentration of antimicrobial agents.
Microorganisms Associated with Paint
Microorganisms associated with paints
and paint films have been well established. Pseudomonas aeruginosa is
predominant bacterium isolated from spoiled latex emulsion paints in
container. A much greater number of fungi and bacteria are found on and
paint films, although again one fungus and one bacterium predominate.
Goll and Coffey
were the first to observe and report the wide spread growth of
pullulans. In isolation studies of oil and alkyd paint films at six
geographical locations, Rothwell confirmed the predominance of P.
but noted the close resemblance of, and predominance in, certain
areas of Cladesporium sp. Other fungi frequently isolated included
dianthicola and Phoma pigmentivora. The same studies indicated the
presence of bacteria within the paint film and at the paint wood
Flavobacterium marinum was by far the predominant bacterium isolated.
the differences in the chemical nature of latex emulsion binders.
isolated essentially the same micro organisms from latex emulsion paint
exposed at the same location.
The microflora of interior paint films
in breweries, dairies, canneries, and other food processing plants was
by Krumperman and included many fungi rarely found on exterior paint
Prominent among these are Aspergillus species and Penicillium species.
species and P. pullulans were found to a lesser extent. His
again indicated the frequent occurrence of the bacillus F. marinum.
Growth Structures of Fungi
Fungi are present on the surface of
paint films in two forms. They may be present as thread like
technically referred to as mycelia or as clusters of spherical, usually
spores. These two different appearances of fungi have been popularly
the trees and fruit of fungi. In actuality, they represent the two
growth forms in the life cycle of the fungi. The mycelial structures
observed when the fungi are actively growing and reproducing. Spore
are found when conditions for growth and reproduction are less
Spores are more resistant to environmental changes and antimicrobial
than the mycelial forms.
The mycelial growth structure of fungi
is recognized easily by its thread like form. Spores and spore clusters
frequently difficult to differentiate from soil or soot particles, and
examination with a magnifying lens or microscope is frequently
positive identification by even the skilled microbiologist.
of the two different forms of fungal growth. Whenever doubt exists to
surface disfigurement is fungus or dirt, culturing the deposit on
glucose extract agar, potato dextrose agar, or other suitable culture
will provide the final answer.
Chemical Methods for Fungal Identification
The protein nature of fungi permits
the use of chemical identifications. Treating disfigured paint films
sodium hypochlorite bleach solution containing 5 percent of sodium
in water is generally employed. The bleach solution is applied to a
small area of the paint film when this disfigurement is representative
observed in the overall surface. It is allowed to remain approximately
1 min at
which time the treated area is flushed with water and blotted with
Bleaching indicates that the
disfigurement is fungus. The test has its limitations and thus should
interpreted with some degree of caution. Insect eggs or fecal material
bleach since both are composed of protein. The test should be limited
or lightcolored paint since on deeper colored paint films, the
fungal growth may be insignificant compared to that of the paint.
heavy chalk face interferes with the test and areas discolored by metal
give false results.
Chemical agents, used to control or
prevent the deterio rating effect of microorganisms, are referred to
biostats if they do not kill microorganisms but prevent their
as biocides if they kill. Such agents used in paint films fall into two
distinct categories that include inorganic pigments and organic
oxide and barium metaborate are examples of the first category, and
phenylmercury compounds and chlorinated phenols are examples of the
category. Some of the more frequently employed antimicrobial agents
paint are listed in Table 1. Most of the microbistats and microbicides
paint films effectively control fungi and bacteria by interfering with
Bacterial Resistance of Liquid Paints
Resistance of emulsion paints in the
container to attack by bacteria can be determined in accordance with
Method D 2574, Resistance of Emulsion Paints in the Container to Attack
Microorganisms. This test predicts the package stability of water
emulsion paints as related to bacterial growth in the paint and
protein and cellulose thickening agents.
The test consists of two parts. The
paint under test is first cultured on tryptone glucose agar to
living bacteria are present. A negative result indicates the absence of
bacteria but not necessarily resistance to attack. To determine if the
paint can withstand bacterial attack, a specimen of spoiled paint
Pseudomonas aeruginosa is introduced into the test paint and the latter
incubated at room temperature for a period of six weeks. At intervals
48, and 72 h, and at one week intervals for the remainder of the test
the inoculated test paint is streaked on tryptone glucose extract agar
The test paint is reported to be resistant to bacterial attack if no
organisms can be recovered through six weeks of incubation. Conversely,
paint is reported to be not resistant to bacterial attack if living
are recovered at anytime during the incubation period. The principal
in the ASTM test and previously employed tests of this type is the use
spoiled paint as an inoculum, rather than aqueous suspensions of
removed from laboratory growth medium. By employing paint containing P.
aeruginosa, already adapted to a paint environment, the shock of a
environmental change is eliminated. Repeated inoculations may be
obtain a spoiled paint for use as an inoculum, but, once prepared, it
Measuring the Fungal Resistance of Paint Films
The inability to duplicate the use
environments of exterior and interior paint films has made it difficult
develop suitable accelerated tests for the evaluation of their fungal
resistance. Most laboratory tests have been based on the widely used
method or modifications of it. Simply described, the agar plate test
of placing a painted substrate on a bed of agar, inoculating the system
the test organism and observing growth during a prescribed incubation
Method The ERDL
(Engineer Research and
Development Laboratories) method, which is the agar plate test most
referred to in specifications for paints utilized by agencies of the
States government, employs sucrose, mineral salts, agar medium, and
oryzae as the inoculating organism. The agar medium is prepared
the recipe shown in Table 3. The pH of the medium may be adjusted to
5.5 to 6.5
with 0.1 N hydrochloric acid (HCl) or sodium hydroxide (NaOH). The
sterilized in an autoclave for 15 min at 15 psi and 121 C.
Approximately 30 ml
is poured into sterile petri dishes and allowed to harden.
The inoculum is prepared by adding 10
ml of sterile water containing 0.005 percent nontoxic wetting agent
Tween 80 to a tubed subculture of A. oryzae. The mixture of spores and
are removed by gently stroking the agar surface with a sterile camels
brush. The aqueous suspension is removed and diluted with sterile water
Using a sterile pipet, 1.0 to 1.5 ml
of the diluted spore mycelial inoculum is distributed over the painted
and surrounding agar surface. Duplicate plates should be prepared. The
inoculated agar plates are incubated for 7 days at 28 to 30 C and 90
relative humidity. At the end of the incubation period, the specimens
examined at 1 and approximately 18 magnification. Fungal growth on the
surface or on the sides of the painted filter paper is ignored, and
specimens are considered to pass the test.
Method In order
to improve its
accuracy, the ERDL test was modified by the Nuodex Laboratories as
Pullularia pullulans replaced Aspergillus oryzae because it is the
frequently isolated from exterior house paints. Malt extract agar
sucrose mineral salts agar because, in it, P. pullulans exhibits growth
that are typically observed on exterior paints rather than yeast like
that it exhibits when grown on the sucrose mineral salts agar.
method is similar to the ERDL agar plate test but employs glass string
than filter paper as the paint substrate, a liquid broth culture media
containing no carbon source and a mixed spore suspension of Aspergillus
Aspergillus flavus, and Penicillium leterium. The glass string is
the test paint which is then allowed to dry for 48 h. Then the string
into the spore suspension for 1.5 min. One inch sections are the placed
Environmental Chamber Test Subcommittee
28 of ASTM Committee D 1 has developed a tentative method for measuring
resistance of interior paint films to fungus attack. This test
provides more accurate results by virtue of removing the artificial
previously described laboratory method. Test paints are applied to
pine or gypsum board panels measuring 3 by 4 by 0.5 in. The specimens
conditioned at 75 F and 50 percent relative humidity for 4 days after
application of the last coat before being placed in the test chamber.
chamber may be any cabinet capable of maintaining a relative humidity
of 95 to
100 percent and a temperature of 90 F and large enough to accommodate
specimens, a water bath, and a soil bed that serves as an inoculum
soil bed is constructed of a stainless steel or plastic tray with a
bottom (16 mesh). The soil employed is a good quality, greenhouse grade
soil containing 25 percent peat moss. The pH of the soil is maintained
5.5 and 7.6. The soil is inoculated with spore, mycelium suspensions of
Pullalaria pulluluns, Aspergillus niger, and Penicillium sp. prepared
to 14 day old agar slants. At least 14 days should be allowed for the
sporolate prior to beginning any tests.
WEATHERING TESTS NATURAL WEATHERING
The final test of a paint is its
performance under actual conditions of use. For exterior paints, this
the walls of buildings, railway cars, highway vehicles, ships, and the
Such tests are expensive and time consuming. Hence, there has developed
practice of conducting tests on a small scale. These screening tests
studies of the effects of many variables to be made in a fraction of
and at a fraction of the cost of full scale tests. For final judgement,
scale tests must usually be made.
Many variables enter into the testing
of paints on a small scale, and it is doubtful if small scale tests can
be the basis for positive statements about the performance of paints on
structures. Under the practical conditions existing during the painting
exterior surfaces, the effects of weathering may not always agree with
that occur in small scale tests. The differences may arise, not from
compositions of the paints, but rather from the technique of
schedule of maintenance, or from other factors such as differences of
and moisture content between buildings and test panels, particularly
Weathering tests are necessarily long
time undertakings, requiring very careful planning and preparation. It
not be attempted unless it is possible to make it the major duty of at
one adequately trained man. Evaluation of weathering tests may be more
informative if certain laboratory tests are made during the exposure
The trend of changes in properties such as distensibility, adhesion,
porosity may be used to predict the probable usefulness of a paint.
The type and rate of failure of a
paint film varies different combinations of climatic conditions. Hence,
climate of the test site should be representative, geographically,
climatically, and in atmospheric contamination, of that of the location
which the paint is to be used (Table 1).
The sun is an important factor in the
degradation of paint films. It raises the temperature and thus
rates of chemical reactions with oxygen or with gaseous contaminants
be present in the atmosphere or between ingredients of the paint
actinic radiation of the sun catalyzes many of the reactions.
temperature, caused by the day night cycle and by clouds, impart
stress (expansion and contraction), resulting in gross cracking at one
the scale and microscopic cracking at the other end. The latter may
itself as adherent dust (chalk). Sudden severe drops in temperature
known to pop paint from galvanized metal.
Water is one of paints worst enemies.
It causes blisters and peeling, and promotes the growth of mold on the
In the form of dew it is more harmful than rain. Dew forms within
makes intimate contact with the paint film. Water as rain often flows
cracks without entering them. By remaining in contact with the film,
promote reactions with dissolved contaminants. Rain may wash these
away and thus minimize the reactions. Tests started on arid, sunny
tops did not start to chalk until they were brought down to sea level.
The simplest type of rack is one to
which the specimens are fastened by nails or screws to horizontal
are held in place flaps or in grooves. Slots and grooves, if wide
to protect a portion of the surface, thus allowing changes of
appearance to be
readily noted. A hinged flap over the top of the specimens is probably
because less dirt accumulates. The advantage of this construction is
with which the specimens may be removed for careful inspection in the
laboratory. A simple rack of this type is described in ASTM Recommended
Practice D 1006, Conducting Exterior Exposure Tests on Wood.
A type of rack that simulates actual
wall construction of a wood frame house. There appears to be little
to this type, since under the conditions of the test there is little or
condensation of moisture within the stud space. However, for other
might select it or a similar type.
The lower specimens on an ordinary
rack are subject to contamination by runoff water from the higher. To
this disturbing factor, racks in which each row of horizontal specimens
offset have been designed.
To use more of the suns energy, it is
common to tilt the racks toward the sun, a compromise angle of 45 deg
usual practice. Walker calculated the relative amounts of energy
specimens oriented vertically at 45 deg and at an angle equal to the
of the exposure site. Inspection of the data in Table 2 shows that the
intensity at 45 deg is from 1.35 to 2.44 times that received at 90 deg
several different latitudes in the United States.
Estimates derived from actual exposure
tests range from 2 to 3 (Table 3). Many authorities hold that exposure
deg cannot be accepted as accelerating all reactions occurring in paint
equally. In some films, chalking may be accelerated in others,
other words, changing the angle from vertical to 45 deg is equivalent
conducting the test in a different climate, and the effects of climate
In order to use the suns energy more
effectively, Gardner suggested that racks be built in the manner of
telescopes so that they would face the sun at all hours of the day. A
demonstration model was built by supporting the rack on pivots in a
allow the angle of inclination to be varied. The yoke in turn was
mounted on a
post on which it could be turned continuously to face the sun. The
inclination was changed manually at regular intervals during the day.
was rotated mechanically by water power.
A far simpler system is described by
Daiger. Experience has demonstrated that 45 deg exposures in Florida
chalk fade of automotive and industrial finishes without seriously
the relative performance in other respects. Exposures at the horizontal
5 deg to obtain even greater acceleration have been gaining favor.
an annual basis, either angle has a drawback. Tests started in summer
a faster rate than those at 45 deg, but tests started in winter chalk
slower rate. The solution to the dilemma is to change the angle at
that the specimen is never more than 5 deg from perpendicular to the
The trend to a more effective use of
the suns energy was continued by Caryl and Helmick by using an
mount. But even this ambitious step did not satisfy them. The machine
redesigned to use mirrors (up to ten) to increase the suns radiation
specimens. The new machine was christened EMMAQUA for Equatorial Mount
Mirrors for Acceleration plus AQUA (water). In this machine the
located on the underside of a cross member at the top of the machine,
target area, 6 ft by 6 in. The mirrors, opposite the target, face the
reflect its energy back to the specimens. The mirrors are bright rolled
aluminum sheet with Alzak finish and reflect about 85 percent of the
radiation and about 70 to 80 percent of the ultraviolet. With ten
specimens receive about eight times the radiation received by a simple
mount and ten times that received by a 45 deg exposure. A strong
current of air
keeps the surface temperature in the range prevailing in the 45 deg
Present, practice is to operate the
machines only on sunny days from 7:30 am to 4:30 pm in the summer and
am to 3:45 pm in the winter.
A comparative study of four types of
house paint and of six automotive finishes showed that 14 weeks in the
machine correlated very well with 3 years exposure at 45 deg in
On the other hand, as a result of
tests on pigments, Papillo concluded that The EMMAQUA cannot be used in
absolute way for prediction of service life or for quantitative
the relative performance of two pigmentations, using 5 deg South
exposure as standard. The unit has been found very reliable, however,
providing qualitative information regarding relative weatherability of
coatings. It is considered useful as a time saving adjunct to screening
programs in the development of new pigments for high fastness coatings.
Specimens for exterior exposure should
be painted out of doors in suitable painting weather. The exception
when tests are designed to study the effect of adverse weather for
the performance of the paint. It is permissible to apply the paint
provided that the specimens are removed immediately to the outside for
Alternately, an open shed or a canvas shelter might be used. If both
and dried indoors, undercoats may remain uncured and checks may form in
coats. On the other hand, films may not cure properly if the painting
out of doors during cold or damp weather, or in an industrial area
with acidic gases. If, during winter, specimens must be prepared
shipment to remote test sites, it is advisable to cure them in well
rooms or cabinets through which outside air, suitably warmed, is
hot, sunny summer weather, it may be advisable to attach the panels
to the shady side of the test rack during the application and drying
subsequently removing the panels to their permanent location.
When the purpose of the test is to
compare commercial paints, it may be appropriate to apply them at what
be their natural spreading rates. When the purpose is to study
composition, the paint should be applied at suitable predetermined
Unless the paint chemist is careful,
he may find that he applies paint to small specimens at a greater
rate (less paint) than does the experienced painter. For this reason,
laboratories find it desirable to employ painters for this work.
Panels of factory applied paints
should be inserted in the production line or on a specimen of the
product, or a specimen cut from the finished product should be taken
Wood test panels and their selection
should receive careful consideration. Extensive tests made in eleven
parts of the United States showed that the species of wood has a very
pronounced influence on the durability of the coating (Table 4).
within a given species, paint holding properties are influenced by
grain, and grade. Boards of average density, edge grain, and select
paint better than boards of high density, flat grain, and grades
numerous knots and pitch streaks.
Plywood for general paint tests should
be the exterior type in which water resistant glue has been used. Hard
should be of the exterior grade and tempered.
Large specimens not nailed or screwed
to a rack might well be reinforced across the back with wood or channel
cleats to prevent warping.
The paint technologist must bear in
mind that lumber is rarely chosen primarily for its painting
To the user of lumber other properties, such as cost, availability and
properties are also important. Therefore, if time and space are
testing procedure should include a poor paint holding species such as
pine, a good paint holding species such as western red cedar, and
intermediate, species such as white pine. If paints being compared
slightly in ordinary performance, the use of poor paint holding species
vital to a proper evaluation of the paint. These principles and
the subject matter of ASTM Standard D 358, Wood to be used as Panels in
Weathering Tests of Paints and Varnishes.
In addition to standard panels all
tests should include a standard reference paint. The best way to
features is by the use of matched specimens. According to this
reference paint is applied to a portion of the panel that receives the
competitive paint. It is convenient to apply the reference paint to the
midsection and the other paints to the end sections. This makes it
obtain evidence of paint performance otherwise obtainable only by
many more separate specimens. In any event, duplicate specimens are
To be statistically sound five specimens should be tested.
One of the earliest tests of paint on
iron and steel was started in 1908 at Atlantic City, N.J., under the
of ASTM. Several hundred 18 gage panels, 18 by 36 in., were used. One
was to find the relationship between the Thompson laboratory test and
weathering. The results are summarized in Table 6.
In some respects, weathering tests on
metal, such as iron and steel, require more attention to details than
on wood. Rust and mill scale vary in nature and amount. Pretreatments
common. Contamination by fingerprints must be considered.
Shapes have a great effect of
weathering. Angles and curves form pockets that trap water, shield
surfaces from the sun, or present them more directly to the sun.
wood, a larger percentage of outdoor metal surface is oriented at
than vertical. Thus, to develop the complete picture of the performance
paint on metal, flat specimens should be exposed horizontally and at 45
well as vertically structural shapes should be included.
SPECIFIC PRODUCTS TESTS ON VARNISHES
Tests described in this chapter apply
10 oleoresinous and catalytic cured varnishes, such as exterior,
floor, and rubbing varnishes to nonoxidizing types, formerly known as
varnishes, such as cellulosic, vinylic, and acrylic lacquers shellac
seater. Most of the tests are listed in ASTM Methods of Testing D 154,
and D 333 Clear Lacquers and Lacquer Enamels. Many appear in both
TESTS ON LIQUID VARNISH
To determine the presence or absence
and to describe the nature of undesirable solid matter or nonmiscible
clear liquids varnishes and lacquers, among others is the purpose of
Method D 2090, Clarity and Cleanness of Paint Liquids. Various terms
become established in the coatings field to describe the nature of the
Foreign matter is anything visibly
unrelated to the origin of the material.
Sediment is any solid, such as foots,
grain, or gum that can settle or be centrifuged from the liquid.
Skins are partially solid layers of
material, usually formed from the liquid itself.
Turbid describes the presence of non
settling, suspended matter in a concentration high enough to reduce
Haze describes the presence of
nonsettling, suspended matter in a concentration not high enough to
transparency to translucency.
Clear describes a complete lack of
visible nonuniformity when viewed in thick layers in bottles or test
strong transmitted light.
Clean describes a complete lack of any
visible nonuniformity when viewed in thin films.
Examination should be made under at
least 50 ft candles. It is convenient to use the specimen prepared for
determination of viscosity by the bubble method.
Tilt the tube just slightly from the horizontal so that
bubble moves slowly and permits observation in the moving liquid of
that might otherwise escape detection. It may be helpful to charge a
tube with the liquid, to allow both tubes to stand for 24 hand note any
sediment to shake one tube thoroughly and, after the bubbles have
compare the appearance of the tubes (any difference indicates haze or
Drain one tube, replace the stopper, and let stand for 15 min or until
complete and a thin film protected from dust remains. Strong
reflected light may reveal particles that otherwise escape detection. A
may appear clean in a thick film but not clean in a thin film. For a
of temperature and some other factors, the reader should consult the
The color of liquid varnish is only an
indication of the color of the dry film. The initial color may bleach
or other color
develops, depending upon the conditions of exposure.
If the intensity of the color is
appreciably greater than water white, comparison with Gardner Color
is recommended. Paler colors may be in the range of the platinum cobalt
The effort required to apply a varnish
is related closely to its viscosity. For application by brush it is in
range of 1 to 2 stokes for application by spray it is somewhat lower
application by roller it is higher. Lithographic varnishes and vehicles
paint may have viscosities as high as 100 stokes.
Gardner Holdt bubble tubes are used
widely for determining the viscosity of oleoresinous varnishes. The
Ford cup is
used for nontransparent varnishes. For precise determinations needed in
research, capillary viscometers are often used.
Bodying reactions may continue for
several days after a varnish has been thinned. If the extent of the
be predicted, thinning and storing can be done with confidence. A
doing this follows. The viscosity of an aged batch of the varnish is
over a convenient temperature range, say 77 to 130 F, and a
temperature/viscosity curve is constructed. The viscosities of several
are determined at catch temperatures. The viscosity at 77 F of each
estimated by drawing curves, parallel to the first one, from the catch
temperature to 77 F. The average increase due to aging is thus
obtained, and a
new curve, the standard for future batches, is constructed.
For several reasons a laboratory
determination of nonvolatile content may not agree with the actual
the elevated temperature of the determination, reactions of
varnish with oxygen from the air may proceed in directions different
at the ambient temperatures of drying. Reacting resinous constituents
catalytic cured varnishes may eliminate water or may add moisture from
Cellulosic lacquers may lose plasticizer. Several methods for the
The nonvolatile content by volume is
recognized as a factor in film thickness.
Two general methods, A and B, are
described in ASTM Method D 1644, Nonvolatile Content of Varnishes.
tends to give higher values, especially for strongly oxidizing types.
varnishes containing highly volatile thinner, Method B is not
because of the potential danger at its higher temperature.
Resin solutions are essentially a type
of varnish. They usually contain more solids than do varnishes.
they are more viscous and tend to trap solvent. Ways to avoid the
are given next.
Oil Addition Method This method is essentially
the same as Method
A, previously mentioned. The difference is the addition of 0.5 to 1.0 g
medium body soybean oil to the dish as a part of the tare weight. The
to keep the specimen open during the heating. As a check on loss of
a blank may be run.
Film Methods These are to be found in
ASTM Method D 1259,
Nonvolatile Content of Resin Solutions. There are two modifications: A,
nonheat reactive resins, such as ester gum and alkyd B, for heat
resins, such as formaldehyde reaction products with urea, melamine, and
and for resins that release solvents slowly such as epoxy resins. The
practical difference is the duration of heating. A unique feature is
thin film that minimizes retention of the solvent.
A sheet of aluminum or tin foil, 6 by
12 by 0.0015 to 0.0020 inch. is weighed. One end is placed, shiny side
up, on a
sheet of plate glass and rolled smooth, if necessary. The sandwich is
and placed on the tray shown in Fig. 1. and the tray is placed in an
(gravity or forced ventilation) at 105 C for 30 min. The specimen is
removed from the oven, the sandwich is closed, and the determination is
completed in the usual way.
The procedure is the same as for
Method A except that the specimen is heated in a forced ventilation
oven for 2
Vacuum Method According to this
method, the solution is diluted with a high boiling liquid, such as
phthalate, and heated under vacuum, with agitation, to distill the
solvent in which the resin was dissolved. As shown in Fig. 3, two
rocked about an axis passing through the bottoms. The flasks hold 50 ml
connected to the vacuum, a manometer, and to two solvent traps cooled
mixture of Cellosolv and dry ice. Between the flasks and the manometer
needle valve to control the pressure.
In each of the two flasks are placed
six steel balls to provide bubble forming surfaces, and 10 ml of
dibutylphthalate. The flasks are weighed and from 2 to 3 ml of resin
are added to each, and they are again weighed to obtain the amounts of
specimens. The flasks are clamped in position and lowered into the
is kept at 100 c. With the needle valve open, the pump is started and
rocker arm set in motion. The valve is closed at a rate that causes
boiling and establishes full vacuum in 5 min. Distillation is continued
min at a bath temperature of 100 C, or
30 min at 110 C. Some specimens may require other temperatures and
periods. At the end of the period, air is admitted to the flasks, the
stopped, the flasks are detached and allowed to cool, are wiped clean
weighed, and the percentage of nonvolatile matter is computed. A blank
on the dibutylphthalate. If it loses more than 5 mg, the supply is
dry air for 48 h. An accuracy of 0.2 to 0.3 percent is claimed.
Methods for Cellulosic Lacquers In
these methods the solids are precipitated with a nonsolvent, the
matter is evaporated on a steam bath, and the nonvolatile is dried and
Two variations are practiced.
Method A is suitable for cellulose
nitrate base solutions and lacquers that contain no toluene soluble
Method B is suitable for high
viscosity lacquers. From 4 to 6 g, weighed to the nearest milligram, of
lacquer is transferred to a tared 70 mm aluminum drying dish containing
stirring rod, diluted with 100 ml. of acetone, and stirred until
complete. The solids are now precipitated by adding dropwise with
stirring, 10 ml. of distilled water. The dish is evaporated to dryness
steam bath and finally dried at 100 to 105 C for 1 h, cooled in a
Architectural paints treated in this
chapter include solvent thinned and water thinned and exterior and
types. Cement base paint is treated separately, even though it contains
The tests are treated in the following
order: Liquid Paint Properties Application and Film Formation and Film
Properties. All tests may not be required for each paint. Selection of
must be guided by experience and the requirements in each case, and be
to agreement between buyer and seller.
Affecting Use of Paint
Substrate may be lumber, wood product,
hardboard, concrete, brick, metal, or even plastic.
Quality of the substrate will depend
on knots and grain in lumber ratio of cement to aggregate porosity of
cinder block, and concrete alkalinity of concrete and mortar or
Type and quality of priming coats.
Weather during and after application
Orientation, such as that of soffits,
fascia boards, porch rails, lumber adjoining masonry, and vertical
Environment, such as sunny or shady
side of structure, proximity of other structures, trees and shrubs.
Character of the structure, such as
presence of structural defects or defect caused by neglect.
Substrate may be wood, hardboard,
wallboard and joint cement system, plaster, metal, or previously
Quality and condition of the
substrate, such as porosity, smoothness, and color. For topcoats,
primer and time between priming and top coating.
Atmospheric conditions, such as
temperature and relative humidity during application.
Condition in the container covers a
number of characteristics, such as the presence of curds, agglomerates,
seeds, putrefaction, and gas, all of which are objectionable under any
condition. Characteristics, such as settling and syneresis, are
if excessive and if the paint cannot be restored to satisfactory
Coarse particles, abnormal viscosity, loss of drying, and color drift
acceptable, if within specification limits.
Examining and reporting the condition
in the container and the storage characteristics of latex paint
special attention because of the possibility of decomposition of the
addition to the immediate examination, as described next, of the
contents of an
unopened, original container, another unopened, original container is
and set aside for a specified period of time and temperature. (Note
I month at 125 F simulates some of the effects of storage for 6 to 12
77 F. However it should be recognized that storage at 125 F may not
accelerate changes that occur at 77 F for example, the growth of some
putrefying bacteria is inhibited.)
Qualities 1, 2, 3, and 6 are rated as
Absent, Negligible, Considerable, or Severe. Qualities 4 and 5 are
rated in the
Solvent thinned paint that contains
oxidizing filmogen is subject to the formation of an insoluble skin on
surface when air (oxygen) has access to a partially filled container.
tendency to skin is measured.
The character and extent of settling
may be determined. The tendency of the pigment to settle naturally is
usually by setting aside a completely filled container for an agreed
period, usually six months. Accelerated tests are also described in the
Agglomerates, and the Like
After any skins have been removed,
and, if the pigment has settled, uniformity has been restored, the
examined for curds, agglomerates, and the like as it flows from the
Generally, in order to produce a film
of good appearance, a paint should be free from coarse particles. The
the film, the more important is this requirement. An exception is
paint, which depends in part, on the presence of coarse particles for
This property is a measure of oversize
particles, not to be confused with coarse particles. Enamels and high
paints should be processed to a high degree of dispersion.
Density (weight per gallon) is a check
on the theoretical weight per gallon and on the uniformity of
is not a measure of quality.
This property bears no direct relation
to the quality of a paint. However, it is information necessary for
solvent thinned paint for shipment by common carrier.
This is a measure of the stability of
a solvent thinned paint when thinned to the desired consistency. The
recommended thinner should mix readily with a minimum of stirring or
According to FTMS Method 4203, the thinned paint is, allowed to stand
for 4 h
and is then inspected for curdling or other precipitation or separation
layers. If there is doubt about the condition, some of the material is
without agitation, onto a glass panel. Any of the phenomena mentioned
then readily observable.
(Viscosity, Rheological Properties)
The principal reasons for determining
consistency are to check the uniformity of manufacturing and to
working properties of the product. Examples of the latter are the Krebs
viscometer to measure the brushing property of a paint and the Ford cup
measure the spraying property of a lacquer. However, the relationships
rheological properties and application (working) properties and
properties of architectural paints is not yet known well enough to
many technologists to depend on the former to describe the latter.
direct determination of these properties has been practiced.
These are descriptive of the paints
response to manipulation by a brush, spray gun, roller, or other means
application. Subjective evaluation with a minimum of instrumentation is
Federal Test Method Standard No. 141
(FTMS). good quality wall brush, a 2 by 2 ft coldrolled steel or an
panel, or a 2 by 4 ft gypsum wallboard panel that has been primed with
standard primer. On the wallboard, the paint is applied in sections
usual back and forth motion. The lay off strokes are applied at a right
to the lay on strokes. Subsequent sections are always worked toward the
edge of the section last painted. The effort required to apply the
the flowing quality are noted. After the film is dry, it is examined
marks, brush marks, and variations in gloss.
Instruments for direct measurement of
brushing properties have been proposed but are not used very widely.
for calculating brushability from rheological data are also available.
This property is important for paints
applied by brush. It is the length of time that a film remains fluid
allow the next lap to be merged into the overlap without visible
It is evaluated usually at the end of a specified period of drying.
The paint is applied to one end of a 1
by 2 ft metal panel, and the film is laid off crosswise, ending along
unpainted half. The panel is placed in a vertical position with the
uppermost. Shortly before the specified wet edge time, the painting of
second half is started at the remote edge so that overlapping of the
occurs at the end of the specified time. If required, the overlap is
brushed, and the second half, is laid off parallel to the first half of
specimen. When the paint is dry, the overlap is examined for
such as film continuity, leveling, gloss, color, etc.
The use of an appropriate gun and a
steel panel not less than 4 by 8 inch. The material is reduced as
the product specification. During the spraying the gun is held
to the panel and is moved in a straight line across the face of the
quick drying material, the spraying distance is 6 to 8 inch for slower
materials, 8 to 10 inch.
The wet film is examined for running,
sagging, and fogging. The dry film is examined for dust, floating,
bubbles, wrinkles, streaks, pinholes, craters, blush, bloom, and
Weigh the loaded roller and roll the
paint on the Morest charts evenly, being careful do not exceed the
the chart. Allow the weight of the roller to spread the paint
by rolling in the direction that produces the smoothest film. Reweight
roller to find the weight of the paint used. If this is not within 10
of the desired amount, repeat the test until a check is obtained, or
is determined that the amount is impractical.
Roller Spatter Test The tendency of a
paint to spatter when applied with a roller may be determined by the
test devised by T. M. Keenan of the David Litter Laboratories. The
caught on a plastic sheet (black for light, colors, white for dark
mounted on the handle of the roller. The sheet is easily mounted on the
by cutting a slit from a long edge to a hole in the middle and securing
faucet washers. The sheet is 2 in from the roller, and the short
parallel to the roller.
These properties may be confusing in
that they may refer (a) to the substrate or (b) to the coating that is
or (c) to the fast coat that has been applied. Usage (b) is preferred
Strong absorption is a necessity for
adhesion or paint to a chalky or rusty substrate. On the other hand,
absorption is desired if a glossy paint or enamel is to exhibit uniform
when applied to porous primers or undercoaters. Penetration and holdout
other names for weak absorption and strong absorption, respectively.
A subjective measurement of primer
absorption may be made according to FTMS Method 6261, Primer
A roughly quantitative measure of
absorption may be obtained by applying the paint to an absorbent
as filter paper.
FTMS Method 4421, Absorption Test,
directs that a frictiontop cover for a half pint can be completely
the paint and covered with a Whatman No. 12 filter paper (12.5 cm is a
convenient size) and allowed to remain for 3 h. The average distance of
migration from the edge of the cover is recorded as the absorption
(penetration). Blotting paper may be also used.
An indirect method for measuring the
degree to which a coat of paint will holdout a subsequent coat depends
penetration of the coat by a special staining agent. The specimen to be
is applied to a nonporous surface, and the reflectance the dry film is
measured. A special ink like compound is applied, the excess is
the reflectance measured again. The difference between the two
determinations is a measure of the porosity of the paint film.
In one form or another this test has
been practiced for many years. It is now being proposed for adoption by
The substrate for the test is a white
plastic or a white cardboard sheet, firmly held on a vacuum plate. The
applied with a blade spreader (width, 6 inch clearance, 0.012 in.),
dry for 48 h and its reflectance then measured. After 5 min the
suspended from one end and the excess of staining agent is removed with
of petroleum spirits from a squirt bottle and a camel hair brush. The
still suspended, is allowed to dry for 3 h, and its reflectance is
Freezing may adversely affect the consistency
and homogeneity of water thinned paint. Two ASTM methods exist for
the extent of the damage a general method, D 2243, Freeze Thaw
Latex and Emulsion Paints, and a specific method, D 2337, Freeze Thaw
Stability of Multicolor Lacquer.
Two 1 pt cans are charged with two
thirds of a pint of the paint. The KrebsStormer viscosity of one
(control) is determined. This specimen is then set aside and maintained
at 25 C
for 168 h. The second specimen (test) is conditioned in a chamber at 9.4 C (15 F) for 168 h. At
the end of the
period, both specimens are allowed to come to thermal equilibrium at 25
(requires about 5 h). After one additional hour, and before being
specimens are examined for settling,
gelation, or other abnormalities. They are then stirred, and their
are determined as described before. Immediately thereafter, and again
h, films are brushed onto hiding power charts. Twenty four hours later
films are examined for differences between the test and control films
differences in hiding power, sheen, or other property.
oils include the more or
less unsaturated glycerides of long chain fatty acids. All except fish
of vegetable origin. Examination of the oils is mainly for quality,
adulteration as low as 5 percent may be sometimes detected. Most of the
are chemical. A few are based on absorption in the ultraviolet portion
spectrum. However, the most promising tools for better methods are
infrared absorption and chromatographic separations
on the Common Drying and Semidrying
known as Mexican oiticica oil, this oil is obtained from the nuts of
Licania arborea. So far as the usual laboratory tests are concerned,
and Brazilian oiticica oil are pretty much alike. The raw oil becomes
on aging but may be permanently liquefied by heat. The raw and slightly
oil wrinkles as it dries, similarly to oiticica and tung oils.
Oil This oil
is obtained from the
seed of Ricinus communis. Its principal characteristics are light
relatively high specific gravity and viscosity, and its solubility in
It differs from other oils in that its composition is mostly hydroxy
acids. It is essentially a nondrying oil, but it may be converted to a
oil by chemical dehydration by which a hydroxy group and an adjacent
atom are removed as water to form a drying oil fatty acid ester with
bonds, one of them being conjugated. This dehydration yields what
known as dehydrated castor oil. in its original undehydrated form,
is well known for its use in resins and as a plasticizer for cellulose
oil is obtained from the seed of chia plants, the best known being
hispanica. The most important habitat is Mexico. A prominent
the oil is its high surface tension, which causes it to crawl. Cooking
at 500 F
for a short time destroys this property.
oil is obtained from the kernels of Indian corn, maize, Zea mays. It is
semidrying, lying between cottonseed and soybean oils.
oil from the plant Gossypium malvaceae, is essentially semi drying. As
is used rarely in paint.
oils are obtained from the bodies of many different
species of marine fish, the most important ones being menhaden (Alosa
menhaden), pilchard (Clupea pitchardis), and the
sardine (Clupea sardinis). The
menhaden is found in the
Atlantic Ocean, while the pilchard and sardine are found in the Pacific
In addition to glycerides of stearic and the lesser unsaturated fatty
fish oils contain glycerides of clupanodonic acid, which appears to
four double bonds.
The iodine value varies
over a wide range, approximately 130 to 190. The tendency of fish oil films
to yellow considerably is due to the
presence of highly unsaturated groups in the molecule.
Oil This is a
semidrying oil obtained from the plant, Cannabis
sativa, usually classed with soybean, poppy seed, sunflower, and walnut oils.
Its use in paints is sometimes reported.
Oil This best
known and most widely used oil in the paint industry is characterized
relatively short drying time. Its high degree of unsaturation, to which
good dry characteristics can be partially ascribed, is due to the
large percentages of linolenic and linoleic triglycerides. Many years
oil was obtained from seed by mechanical pressure including both
presses and later expellers. In recent years the more modern solvent
is used. Oils thus obtained show lower percentages of impurities and
overall quality. Linseed oil responds very readily to a variety of
techniques and is used in the paint industry both as a drying oil and
ingredient in a very array of modified resins of many varieties.
oil, also called candlenut oil, is obtained from the nuts of the tree
molucanna. Although a product of an Aleurites tree, it contains no
elaeostearin. It dries somewhat better than soybean oil.
oil is obtained Iron the
nuts of Licana rigida. It is similar to tung oil in that it has a high
gravity a high refractive index, and similar gel time when heated. The
principal fatty acid, licanic, contains three conjugated double bonds
keto group. The oil supplements the supply of tung oil.
Oil This oil
is obtained from the seed of the perilla plant, a native of the Orient.
most important plants are probably the P. ocymoides L. and P.
Like chia oil, raw perilla oil exhibits the property of crawling, which
decreased by cooking at 500 F for 15 min or more. It has the highest
value of all known vegetable oils except Chia.
oil is obtained from the plant Papaver somniferum and other Papaver
is semidrying and has been used as a medium for artists colors. Like
and most of the semi drying oils, its films are resistant to yellowing.
oil is obtained from Brassica rapa and other species. That from the B.
campestris is called ravison oil. The terms colza and ruben have been
applied to rapeseed oil. In addition to palmitic and stearic acids,
contains considerable quantities of saturated acids with 20, 22, and 24
atoms. The oil has very poor drying properties but finds considerable
use as a
plasticizer for nitrocellulose lacquers.
oil is obtained from the seed of Carthamus
tinctorius, a native of India. It is now readily available
from seed grown
in the United States. Its drying characteristics lie between those of
and soybean oils. One of its main advantages for paint and varnishes is
extremely low after yellowing. This is due to its very low linolenic
Oil This is a
semidrying oil obtained from the plant
Soja hispida, a native of Asia, but also grown extensively throughout
world. When refined it finds wide use as a component in both exterior
interior paints. Its widest use is in the preparation of alkyds.
semidrying oil from the plant Helianthus annus has recently become
important in the coatings industry. Blight resistant strains suitable
growing in the United States have been developed. Its fatty acid
quite similar to that of safflower oil.
is the common name for oil
obtained from Aleurites fordii and Aleurites montana. It is also known
oil, Chinese wood oil. It is characterized by relatively high
specific gravity, and refractive index. It dries and polymerizes under
very rapidly. Its fatty acids are mainly eleostearic, which contains
conjugated double bonds. Its greatest use is in exterior varnish and in
vehicles for exterior paints where water resistance is of prime
device for taking samples is known as an oil thief. For taking samples
casks, drums, and the like, it may be a suitable length of glass
constricted at both ends so that it may be used as a pipet.
it is impossible or impractical to thoroughly mix the nonhomogeneous
of a horizontal cylindrical tank, such as a tank car, a more elaborate
is required in order to get a representative sample. Two such devices
Bacon Cargille Bomb and the Curtin Zone Sampler, Fig. 2. These permit
any level in the tank. The glass construction of the Curtin Zone
the user to check the level where stratification or sedimentation
Samples are drawn from the bottom by lowering the thief with a line
strikes the bottom, when the plunger valve opens automatically,
material to enter. Withdrawal automatically closes the valve. Samples
depths may be taken by the use of a separate line for manual operation
for Dark Oils
number of variants have been proposed for use when the dark color of
obscures the color of the indicator. One scheme masks the
indicator by using a solution of 1.6 g of phenolphthalein and 2.7 g of
methylene blue in 500 ml of denatured ethanol, the pH being adjusted
alkali solution so that
the greenish blue
color is faintly tinged with purple. The color change at
the end point
is from green to purple. Another scheme is to use 100 ml of ether as
solvent. Still another is to add water, salt, and carbon tetrachloride
create a two phase system, in which the indicator enters the supper
layer where it can be seen more readily.
method is of value in determining the pH of oils and varnishes, for it
is this factor rather than the total amount of free acid that is
for some undesirable effects, such as livering. It must be remembered
dissociation of acids in organic media may be quite different from that
aqueous media. Nevertheless, in any specific solvent, for example
benzene, it should be possible to arrange various acids in the order of
activities. Caldwell and decreasing strength in alcoholbenzene for some
acid: sulfuric, benzoic, stearic, mixed linseed fatty, linolenic.
studies have been made of the composition of drying oils during cooking
during the early stages of drying, but, beyond determination of carbon,
hydrogen, oxygen, and peroxides, not enough have been made of the
nature of aged oil films One
the jigsaw puzzle has been supplied by Frilette in his method of
acid values of dry films and relating them to alkali and water
Films are spread on glass plates with a doctor blade, and the dry films
removed with a razor blade. From 30 to 40 mg of film is transferred to
a 25 ml
glass stoppered conical flask. To the flask there is now added 5 ml of
blend of ethanol and benzene, and 0.5 ml of a 0.01 percent ethanolic
of Victoria Blue B as indicator (phenolphthalein is destroyed by
the film). The extract is titrated with 0.01 N NaOH solutions from a
microburet. The first end points fade rather rapidly. As the final end
approached, the flask is warmed in a hot water bath in order to expel
dioxide. The true end point should persist for 10 min, and the entire
may require about I h.
saponification value of an oil is a measure of the molecular weight of
fatty acids. It is not related to the identity of individual oils. It
changed appreciably by polymerization, but does increase with
oxidation. It is
expressed as the number of mg of potassium hydroxide that reacts with 1
oil. The value is useful for certain computations involving the use of
such as the manufacture of alkyd resins.
the determination, the oil is saponified with an excess of alkali, and
excess is determined by back titration with standard acid. Two blanks
tritrated with the acid.
is Method D 1962, Saponification Value of Drying Oils, Fatty Acids, and
Polymerized Fatty Acids.
a conical flask (250 to 300 ml) is transferred an amount of oil,
2.0 g, weighed to the nearest milligram, such that the back titration
from 45 to 55 percent of the blank. To this flask, and to one or two
flasks to be carried through as blanks, is added 25 ml of alcoholic KOH
solution. A condenser loop is placed in the neck of each flask, and the
are heated for 1 h on a steam bath to saponify the oil. The flasks are
and the contents are titrated with 0.5 N sulfuric acid (H2SO4)
or hydrochloric acid (HCL), using phenolphthalein as indicator.
potentiometric method for the saponification value of highly colored
been developed. It is time consuming but has led to a double indicator
in which no blank is required. The first indicator accounts for the
oil is saponified in the regular manner and allowed to cool. Seventeen
ml) of 1 percent alcoholic phenol phthalein indicator are added. The
oil is titrated with 0.5 N HCI until the pink color is discharged. The
of acid need not be noted. The buret is refilled 3 drops (0.2 ml) of
bromophenol blue and 10 ml of benzene are added to the flask and the
is continued to a green end point. This titration represents the
between the blank and the sample in the usual method.
solution becomes yellow shortly before the end point is reached. Then
as the fatty
acids are extracted by the benzene, the blue color returns.
benzene also extracts coloring matter (usually yellow) of the oil.
produces an emulsion of the yellow benzene solution in the blue aqueous
solution, which may appear green momentarily, but the emulsion breaks
when agitation is stopped, and the actual color of the aqueous phase
method fails with oils having fatty acids of low molecular weight
because such acids
give lower pHs than the usual fatty acids.
unsaponifiable matter in an oil is a measure of the materials that are
to water soluble soaps under the conditions of the test. A small amount
unsaponifiable matter is characteristic of all natural oils, varying
conditions surrounding the extraction and refining. Within
the limits of the individual oil specifications, the amount of
matter is no measure of the quality or identity of the oil. An
of unsaponifiable matter indicates contamination with nonglyceride
as mineral oil, hydrocarbon resins, etc.
determination consists in saponifying the oil with alkali and
extracting the unsaponifiable
matter with petroleum ether. An extraction cylinder, glass stoppered,
approximately 35 by 300 mm, with graduation marks at 40, 80, and 130 ml
5 g of sample, weighed to 0.01 g is saponified with alcoholic KOH
resulting soap solution is transferred to an extraction cylinder and
times with 50 ml of petroleum ether. The extract is transferred to a
beaker and evaporated to dryness and constant weight. Unsaponifiable
adulterated drying oils may be volatile and as a consequence may
long heating. Therefore, during the evaporation, the ether fumes should
removed with a current of dry air, and the heating should be
soon as the odor of ether is gone. The residue in the beaker includes
acid that may have formed by hydrolysis of the soap. To correct for
dissolve the residue, after weighing, in 50 ml of warm alcohol
neutral to phenol: phthalien, and titrate with 0.02 N NaOH to the same
point. For further details the original method should be consulted.
amount and nature of the unsaturation in fats and oils indicates their
and rate of heat polymerization. The amount is expressed as the iodine
value centigrams of iodine
absorbed per gram of oil
(percentage by weight). The iodine value is a fairly satisfactory
the relative rate of drying and heat polymerizing among oils of the
however, both properties are affected by the kind of fatty acids and
distribution. Hence, iodine values are not particularly useful for
oils of different types. The measurement of unsaturation is an
the determination of the individual acids for identifying natural oils,
oil has its own range of unsaturation values. Infrared spectophotometry
liquid chromatography are particularly useful for such determinations.
method has largely superseded the Hanus and other methods that tend to
high results. It is particularly applicable to oils having no
bonds, such as linseed, soy, and safflower. Precision and accuracy are
reasonably satisfactory. When applied to oils containing conjugated
bonds the results are only relative and do not measure total
However, the results are reproducible and serve as a basis for
Rosenmund Kuhnhenn method is recommended for measurement of total
driers and metallic soaps
soaps are compounds of alkaline earth metals or heavy metals and
carboxylic acids of 7 to 22 carbon atoms. It is usually convenient to
resinates (usually from rosin) and naphthenates in a discussion of
soaps. Their water insolubility differentiates metallic soaps from
soaps. Their solubility or solvation in organic solvents accounts for
in paints. Commercial metallic soaps are made and used in solid, paste,
liquid forms. The form depends on the metal and its amount, the nature
organic acid, and the presence or absence of solvents or additives
manufacture. Metals of low atomic weight usually form soaps of high
points. Long, straight chain, or saturated fatty acids form soaps of
melting points than do short or branched chains, or unsaturated acids.
made by precipitation are likely to be light fluffy powders. Soaps made
fusion are hard dense solids. Liquid and paste forms are solutions or
suspensions in petroleum or other solvents. It is customary to divide
soaps into two functional groups: (1) paint driers and (2) modifiers of
consistency, gloss, or other properties. The first function is
soaps of lead, cobalt, manganese, iron, and to some extent, by calcium
zinc. The metals found in the second group include zinc, calcium,
barium, and aluminum.
driers are evaluated by both physical tests and by chemical analysis.
other hand concentrated driers are evaluated mainly by their metal
Metallic soaps are evaluated mainly by using them in formulations and
how well they fulfill the function for which they are used. See
Tests on Driers
otherwise noted, the tests in this section are described in ASTM Method
Testing Liquid Driers, or are specified in ASTM Standard Specification
Liquid Paint Driers.
visual inspection discloses suspended matter, the amount may be
filtering an appropriate amount, say 1 to 5 g, washing with turpentine
petroleum spirits, and drying to constant weight at 49 C.
color of a solution of the drier in linseed oil is of
more interest than that of the drier itself. Comparison is made with
standards dichromate sulfuric acid, or other standards.
drier is mixed with raw linseed oil and any cloudiness or other
immediately after mixing, and after 1, 2, 3, and 24 h, is noted.
blend of the drier with raw linseed oil (1 volume +19 volume) is flowed
clean glass plate. The plate is placed in a vertical position, and the
wet to touch
time is determined. This is the time elapsed when the oil does not
stick to the
finger, or the surface is not marred when the finger is lightly drawn
it. It should be noted that this test is somewhat more severe than the
set to touch point.
coined the name Aridyne for the unit of drying power. As a standard
all liquid driers could be compared, he suggested one containing 6.4 oz
of oil soluble
lead per gallon, equivalent to about 6 percent of lead by weight, and
approximately the amount contained in commercial driers. This standard
100 proof. However, since commercial driers usually contain other
addition to the lead, a 100 proof drier is relatively weak. For
purposes, a 200 proof or a 300 proof solution is recommended. If the
contains other metals, the strength is designated in this style: 100
lead manganese, meaning 6.4 oz of lead and 0.64 oz of manganese per
driers that contain no lead, a 100 proof product would have the drying
a 100 proof lead drier.
Tag Closed Cup is used.
1.5 g sample is heated for 3 h at 105 to 110 C in a tared shallow dish,
and weighed. This is essentially the same as Method A for varnish.
any convenient method, such as the Weight Per Gallon Cup. Specific
Balance or a Hydrometer.
Gardner Bubble Method is recommended.
7 days standing, the drier is examined for gelling, clotting, or other
methods for determining the metallic content of driers are still used,
methods based on flame spectroscopy and on chelate titrations using
(ethylene diaminetetraacetic acid) are rapidly replacing the older
One important advantage is that there is no need to remove organic
methods for removing organic matter, when necessary, are ashing, wet
extraction with mineral acids, and conversion to insoluble oxalates.
Separation by Ashing
is one of the oldest methods for destroying organic matter to prepare a
for inorganic analysis.
just to ignition and continue to heat as required to maintain slow
the organic matter. When no more flame issues from the crucible,
heat, over a flame or in a muffle, to red heat for an hour or so.
ash in a minimum amount of nitric acid, and proceed as directed in the
appropriate section next.
Separation by Wet Oxidation This
especially suitable for determining lead as sulfate and is applicable
driers containing lead, manganese, and cobalt.
appropriate amount of drier is transferred to a 400 ml beaker and
heated on a
hot plate until the solvent is removed. About 5 ml of nitric acid (HNO3)
40 to 50 ml of dilute sulfuric acid (H2SO4)
are added, and the
system is evaporated to dense white fumes, the evaporation being
continued to a
volume of about 5 ml. If the solution darkens, a few drops of HNO3 are added from time to time
until it remains
colorless after being heated to white fumes. After the solution is
cool, a few
milliliters of 30 percent hydrogen peroxide (H2O2)
are added, the solution
is boiled for a minute, and carefully diluted to about 100 ml, and
a hot plate to ensure solution of anhydrous sulfates.
Separation as Acetate
sample of drier is dissolved in chloroform or ether, glacial acetic
added, and the system is refluxed.
Separation as Oxalate
appropriate amount of drier is transferred to a 500 ml conical flash
dissolved in 75 ml of alcohol acetone, warmed slightly, if necessary,
solution. Ten ml of a 10 percent solution of oxalic acid in alcohol is
and the system is refluxed for about 1 h. The precipitate is filtered
washed with alcohol toluene.
only lead is to be determined, the metal is isolated by wet oxidation
precipitated as lead sulfate (PbSO4).
After standing for an hour,
the precipitate is collected on a tared Gooch crucible, washed with 0.5
sulfuric acid and then with alcohol, ignited at 500 to 600 C for 15
weighed as PbSO4.
heavy metals and calcium are extracted by a slight modification of
22.214.171.124. The modification consists of working with a 10 g sample in a
tall form beaker, preliminary evaporation of the thinner, and
extraction of the
organic acids with beeswax instead of petroleum spirits. One hundred
milliliters of HCI (1 volume concentrated acid + 4 volume water) and 5
beeswax are added to the nonvolatile portion of the drier and heated to
boiling, with occasional stirrring for 1 h. The system is cooled and
the cake of wax is washed, and the washings are added to the filtrate.
filtrate is made ammoniacal, and the metals are precipitated with
monosulfide. The sulfides are collected on a filter, and the filtrate
reserved for the determination of calcium, if desired.
HNO3 (1 volume acid,
concentrated, 3 volume water)
is poured through the filter, and the filter is washed with hot water.
milliliters of H2SO4 are
added to the filtrate, and the system is treated beginning with the
to dense white fumes. If desired the determination of lead is
filtrate is reserved for the step in the following paragraph.
aliquot of the filtrate is boiled to remove the alcohol, cooled in ice
15 C or lower, and treated with about 2 g of sodium bismuthate for at
min to oxidize the manganese to permanganate.
5 g sample is fused in a large
porcelain crucible with 5 to 10 g of potassium pyro sulfate (K2S3O7). The
mass is extracted with 50 to 100 ml of dilute H2SO4 and filtered through fine
paper to remove the
insoluble sulfates, carbon, etc., and is then diluted to 500 ml in a
flask. To an aliquot containing approximately 50 mg of cobalt is added
of 30 percent hydrogen peroxide, 1 or 2 drops of phenolphthalein
enough 0.5 N sodium hydroxide (NaOH) solution to
precipitate the cobalt
completely and to show an alkaline reaction.
a solution in HCl of the ash obtained or an aliquot of the extract
The sample should contain about 0.1 g of zinc. Manganese, cobalt,
iron interfere and must be removed.
an aliquot of hydrochloric acid extract corresponding to about 0.1 to
0.2 g of
iron. Proceed as directed beginning with reduction with stannous
(ethylenedinitrilotetracetate, according to American Chemical Society
nomenclature, but commonly called ethylenediaminetetracetate) combines
(chelates) strongly with metals used in driers and metallic soaps.
is the disodium salt rather than the free acid that is used in
titrations. The compound is also known by trade names, such as
conducting the reaction in a
basic solution, the hydrogen ion is removed, and the reaction becomes
quantitative. What makes the method so attractive in drier analysis is
extractions or combustions are eliminated in many cases.
addition to the resins traditionally known as natural resins, this
tests on rosin and lac. It does
not include bitumens.
included are tests for the physical properties of synthetic resins the
analysis of which appears in the Chapter.
traditional natural resins are exudations of trees and may be
according to origin as fossil, semifossil, or recent or according to
oil soluble or spirit soluble (Table l).
to most investigators, varnish resins consist largely of resin acids
neutral substances of unknown composition, designated resenes, with
proportions of volatile compounds, ash, and impurities. The absence of
ethers, anhydrides, and lactones (except for rosin) has been suggested.
of Natural Resins
few tests for specific natural resins are available, and none is
satisfactory, except perhaps the Liebermann Storch and the Halphen
for rosin. When the natural resins were much more important in varnish
technology than they are today, their identification was based mainly
color, hardness, and solubility. Today, the availability of many more
should make solubility tests more useful.
to Brauer reagents based on phosphomolybdic and phosphotungstic acids
useful in detecting natural resins and in identifying some of them.
detect resins in linseed oil, a small sample is covered with ether,
drops of a freshly prepared concentrated solution of phosphomolybdic
added, and a few drops of ammonia water. Upon shakling, all resins that
examined gave a typical blue color, which, in some cases, turned
Linseed oil, itself, gave only a faint green.
reagent said to differentiate among resins is made by shaking 0.1 to
0.2 g of
powdered ammonium molybdate with 5 ml of concentrated sulfuric acid.
of a few milliliters of resin solution produces characteristic colors.
gives a Prussian blue color, and addition of ammonia converts the
solution to a
containing coniferin or related compounds give a cherry red color with
examined resins by capillary analysis, which today would be called
chromatography. Strips of filter paper are immersed partially in resins
solutions for periods up to 24 h, withdrawn, and allowed to dry.
pictures appear on the strips, showing strata of different colors,
intensity, opacity, etc. Important variables include type of paper,
solution, depth and time of immersion, size of vessel, temperature, and
relative humidity. Forty eight reproductions in black and white of the
of tests on single resins and mixtures, with full descriptions are
examined the method and concluded that it enables one to distinguish
groups of resins but does not reveal differences within a group.
examined various natural and artificial ambers under ultraviolet
a mercury in quartz lamp transmitting radiation of wavelength 440 to
Natural amber is strongly fluorescent, giving a. greenish light, but
more bluish or yellowish. Nontransparent specimens appear to be bathed
light with bluish or greenish tints. Artificial ambers vary phenol
plastics do not fluoresce, urea formaldehyde plastics emit blue, casein
derivatives bluish to bluish white, celluloid and cellon emit bright
found that a combination of fluorescence and capillary analysis gave
information than fluorescence alone, as zones of fluorescence are often
distinct in one case than in the other.
Storch Test Also
known in Europe as the Storch Morawski
test, this might be considered to be the classical test for rosin and
derivatives. Typical directions are those of ASTM Method D 1542,
Tests for Rosin in Varnishes.
specimen is dissolved in boiling acetic anhydride. To 1 or 2 ml of the
solution in a white porcelain dish is added drop of sulfuric acid (sp
gr 1.43 prepared
by mixing 34.7 ml of 1.84 acid and 35.7 ml of water). Rosin gives a
violet color lasting for a second or two, Stoppel emphasizes the use of
samples (5 to 8 drops
of varnish, for
example), boiling for several minutes, and acid of proper
color produced by ester gum is less blue than by rosin. Elsner observed
copal and sandarac tend to give the same color that turpentine in
Modification of L S Test
0.1 to 0.05 g of sample in 3 ml of chloroform add 5 ml of sulfuric acid
1.56 to 1.58) and shake thoroughly. After the chloroform layer becomes
add acetic anhydride drop by drop. If the merest trace of rosin is
chloroform layer becomes purple. By repeated vigorous shaking, the
acid layer dissolves the coloring matter and becomes carmine to
The amount of sample should be regulated in order to avoid a color that
Hicks Test This
test, along with the Liebermann Storch,
appears in ASTM Method D 1542. Two reagents are needed.
a small quantity of the sample in 1 to 2 ml of the phenol reagent. Fill
cavity of a spot plate with the solution so that some of the solution
beyond the cavity. Immediately in an adjacent cavity transfer about 1
ml of the
bromine reagent so that bromine vapors will spread over the other
may be helpful to cover both solutions with a watch glass or to move
bromine vapors with a gentle current of air. A fugitive violet color
the presence of rosin.
a test tube, slowly heat from 0.2 to 1.0 g of resin with 2 to 3 g of
oxide and pass the fumes over several drops on nitric acid (sp gr 1.4).
reddish violet color indicates rosin. The color changes to green and
blue. It has been stated that lac reacts similarly.
method is claimed to be approximately quantitative for rosin in
ceresin, etc., substances that give no color with nitric acid (spgr
1.33). The sample is added to 5 times its volume of the acid. The
boiled for 1 min, then diluted with an equal quantity
of water, and treated with an excess of ammonia. Rosin produces a red
However, according to Stock the method is indicative only, and not
when other resins are present.
may be recognized by the odor developed upon heating. Unbleached lac
also identified by the dark purple color of its alkaline solution.
resins do not give this color, but some synthetic ones may.
to Bhattacharya unbleached lac is the only common natural or synthetic
which is in any degree soluble in aqueous alkali bisulfite solutions. A
percent solution of the bisulfite will dissolve up to 50 percent of its
of lac. The solubility of lac decreases with age and its degree of
Grades of Natural
are based on color, amount of impurities, and size. Usually the amount
impurities increases with decrease in size.
parameter is not particularly useful for characterizing or identifying
The index of synthetic resins is somewhat higher than that of natural
4. For low melting point resins or for solutions, the Abbe
refractometer may be
used, but immersion methods using the microscope are probably more
indirect method is to determine the indexes of a series of solutions of
increasing concentrations, to plot the indexes against the
to extrapolate to 100 percent concentration.
do not exhibit sharply defined melting points as do crystalline organic
compounds. As the temperature rises resins gradually soften and become
brittle and less viscous. In a sense, determining softening point is
determining viscosity under arbitrary conditions. For results to be
procedures must be rigorously defined. Dimensions of apparatus, the
recent history of the specimen, and rate of heating must be
method has been used. The temperature at which the resin begins to
coalesce is the arbitrary softening point the temperature at which it
powdery appearance and becomes completely transparent is the melting
Examples of some softening and melting points obtained in this way are
and Ball Method
is ASTM Method E 28, Softening Point by Ring and Ball Apparatus,
ASTM Committee D 17 on Naval Stores.
of cellulose used
in paint and related materials include the inorganic ester, the nitrate
organic esters, the acetate, acetate propionate, and acetate butyrate
ethers, methyl and ethyl, and some of their derivatives, such as the
ethyl, the hydroxypropyl ethyl, and the carboxymethyl.
The tests in this chapter are for
quality and uniformity.
Soluble cellulose nitrate, also known
as nitrocellulose, is a white amorphous powder or cotton like solid. It
always handled dampened with at least 20 percent of water, or 20 to 25
of an alcohol. For some uses, toluene is the dampening liquid. In the
condition, cellulose nitrate presents no unusual hazard. Dry cellulose
if ignited by fire, spark, or static electricity, burns very rapidly.
never be stored.
ASTM Specifications and Methods of
Testing D 301, for Soluble Cellulose Nitrate, covers appearance, ash
nitrogen content, stability, viscosity, solubility, and appearance of
film formation, and toluene dilution ratio. It also includes
drying the dampened material needed for some of the tests.
The producer, of necessity, makes all
of the tests routinely. Rarely, if ever, is it necessary for the
manufacturer to make any tests other than viscosity, solubility and
of solution, film formation, and toluene dilution ratio.
Drying Cellulose Nitrate: This is a
necessary preliminary operation for most tests, as the results are
based on the
dry weight of the cellulose nitrate. Also, most formulations, in
based on dry weight.
Only the amount necessary for
immediate testing should be dried. Excess material and specimens left
testing should be wet with water and destroyed by burning on a safe
Larger amounts may be dried by passing
warm (60 to 65 C) compressed air through the material for about 1 h.
shows equipment suitable for this purpose.
If the cellulose nitrate is dampened
with alcohol, it is best to dilute with a small amount of water before
This test is not often made by the
coatings manufacturer. It is the viscosity of a specific solution of
cellulose nitrate and is the key to the viscosity of coatings made with
specific grade of cellulose nitrate. The standard method is described
Method D 1343, Viscosity of Cellulose Derivatives by the Ball Drop
Solutions are prepared according to one
of the formulas in Table 1 with the dried cellulose nitrate dried. The
dries faster if it is first wet with alcohol and toluene and the
allowed to stand for a few minutes before the ethyl acetate is added.
is completed by tumbling or shaking and is brought to 25 C for the test.
and Appearance of Solution
is a check on the
possible presence of impurities that might discolor the solution, or
haze, grain, or flock, to it. The cellulose nitrate is dissolved
Formulas A, B, or C (Table 1), and the solution is compared with a
solution of the reference standard, similarly prepared. The comparison
in small vials on the basis of color, turbidity, grain, and flock.
Solutions of the sample and reference
standard, prepared and diluted with equal volumes of n butyl acetate
side by side on a clean glass plate and allowed to dry in a nearly
position. When dry, the sample film is rated against the reference film
basis of undissolved particles, gloss, and flow.
This is a simplified version of the
method. The solution contains 12.1 g of the dry cellulose nitrate in
87.8 g of
n butyl acetate. Fifty milliliters of the solution is titrated with
the first permanent separation of cellulose nitrate. No adjustment of
concentration is made.
Nitrate Base Solutions
These are prepared by dispersing
various kinds and concentrations of soluble cellulose nitrate in
blends. Since the compositions of the solutions vary widely, the limits
for a specific type must be agreed upon by the interested parties.
methods of test appear in ASTM Method D 365, Testing Soluble
Solutions. The following tests are specified, and coatings
usually make all four.
Three methods for this parameter are
specified. The one to be used depends on whether the viscosity,
ASTM Method D 1343 is: (1) from 3 to 500 s, (2) less than 3 s, or (3)
Proceed as directed in Method A for varnish.
Method B for varnish is potentially dangerous because of the higher
A method that avoids oven hazard and
also the possibility of entrapping solvent in the nonvolatile residue
the cellulose nitrate with toluene (xylene or highflash naphtha, if
boiling solvents are present in the base solution), evaporates the
solvent in a
steam bath, and finally dries the precipitate in an oven at 105 to 110
incidental feature is handling the specimen in a collapsible tube.
About 20 g
of the base solution is loaded into a collapsible tube (available in
stores). From 4 to 6 g, weighed to the nearest milligram, is
transferred to a
tared 100 ml beaker containing a glass stirring rod. Without delay,
buret, 5 ml of toluene for each gram of solution is added slowly, with
stirring, to the base solution. Too rapid addition may precipitate the
cellulose nitrate as lumps. The beaker is now suspended in a steam bath
the solvent has evaporated (20 to 30 min). Water on the outside of the
is wiped off, and the specimen is dried at 100 to 105 C for 1 h, or to
weight, cooled in a desiccator, and weighed.
The depth of color is matched against platinum
cobalt or caramel standards depending on which standards include the
for the description of the standards.
Cellulose Acetate is a white,
tasteless, odorless, fluffy powder. Unlike cellulose nitrate its
is low, and its handling presents no unusual hazard.
ASTM Method D 871, Testing Cellulose
Acetate, covers color and haze, combined acetyl or acetic acid content,
acidity, heat stability, hydroxyl content, intrinsic viscosity,
content, primary hydroxyl content, sulfur or sulfate content, and
The coatings manufacturer usually restricts his testing to viscosity,
haze, and solubility and appearance of
the ball drop viscosity
of a solution of the dry cellulose acetate in a solvent and at a
agreed upon by the interested parties. Suitable formulas are listed in
for color and haze of
cellulose acetate solutions are made by comparison with liquid
standards in the
light box shown in Fig. 2. The box is 17 in. high, 14 in. wide and 13
On the front is an enclosed shelf for the specimen and the color and
The color standards are solutions of platinum
and cobalt. The haze standards are suspensions of fullers earth in
hydrochloric acid solution containing from 10 to 400 ppm. The specimen
rated is dissolved in the specified amount and kind of solvent in the
of bottle used for the color and haze standards French square bottles,
with screw caps. Suggested formulas are listed in Table 3.
The specimen to be rated is placed on
the front of the shelf, and behind it is placed a similar bottle
water. The selected haze standard, freshly shaken, is placed beside the
specimen with the color standard behind it. The standards are changed
until the optimum match has been
found. Ratings for both color and haze are reported in parts per
and Appearance of Solution
Acetate Butyrate and Cellulose
mixed esters of cellulose
resemble cellulose acetate in appearance, but they have more
better solubility, and are compatible with more resins and plasticizers
are the straight esters. ASTM Method D 817, Testing Cellulose Acetate
Propionate and Cellulose Acetate Butyrate, contains the following tests
and propionyl or butyryl contents acetyl content, apparent free acidity
and haze heat stability hydroxyl content primary hydroxyl content
is a white,
odorless, tasteless, nontoxic granular solid. ASTM Method D 914
for moisture content, ash content, chloride content, ethoxy content,
viscosity. Only the viscosity is determined routinely by coatings
Any acceptable method may be used,
Method D 445, Viscosity of Transparent and Opaque Liquids is
there is need for relatively high precision. The determination is made
solution prepared according to one of the formulas in Table 4.
Methylcellulose is a white, or
slightly yellow, odorless, tasteless solid, in the form of powder or
It is available in alkali soluble or water soluble type. ASTM Method D
Testing Methylcellulose, specifies the following tests moisture, ash,
alkalinity, iron, heavy metals, methoxy, viscosity, pH, solids, and
Only viscosity is determined routinely by the coatings manufacturer.
of Alkali Soluble Methylcellulose
This is determined in the same way as
for the water soluble type, except that 1 N sodium hydroxide instead of
water is the solvent.
This material is a white or pale
yellow solid, available as powder or granules. Unlike straight
carboxymethylcellulose, it is soluble in both hot and cold water. Many
based on etherification, viscosity, purity, and other characteristics,
are available. ASTM Method D 1439, Testing Sodium Carboxy
specifies the following tests: moisture, degree of etherification,
purity, sodium glycollate, and sodium chloride. Only viscosity needs to
determined routinely by the coatings manufacturer.
This is an
empirical method for
the viscosity of solutions of sodium Carboxymethylcellulose in the
range of 10
to 10,000 cp at 25 C. Hence, the results do not agree necessarily with
obtained on other types of viscometers.
The concentration to be used should be
agreed upon by the interested parties. It should be such that the
falls within the range of the test. The determinations are run on the
calculated dry basis. The Brookfield viscometer, Model LVF or equal,
selected for the test. The spindle and speeds given in Table 5 are
Hydroxyethylcellulose is a white,
odorless, tasteless solid, in the form of powder or granules. ASTM
2364, Testing Hydroxyethylcellulose, contains only three tests, namely,
moisture, ash, and viscosity. Of these, the coatings manufacturer is
concerned only with viscosity. The method is the same except that the
the solution is 250 g, and stirring at 1500 rpm is permitted in the
thousand high boiling
solvents that impart permanent flexibility to otherwise rigid plastics
been created in recent decades to supplement to relative few available
twenties. The appearance of new types of plastics and their adaptation
uses requiring flexibility has prompted this search. The utility of a
plasticizer is judged by the performance characteristics of the resin
plastic to which it has been added. This indirect test on the
implies that its properties are uniform. In fact, producers place great
emphasis on quality, and the properties determined and methods used are
equal importance to his customer.
physical and chemical
tests are required by the manufacturer to meet his commercial grade
specifications, and by the user to ensure that the plasticizer meets
requirements as a raw material. It is the purpose of this chapter to
basic properties and methods for their determination. It is further
suggest means for isolation, identification, and semiquantitative
of plasticizers present in lacquers and in the dried film after
a substrate. It will be obvious that many of these methods apply
of this chapter
precludes detailed description of the methods involved, but the reader
choose from among the references such tests as he may need.
complexity of the potential
problems involved will be apparent in Table 1. This table lists
types and classes of plasticizers, and major basic types of resins or
which together are classed as lacquer type coatings.
and Chemical Test Methods
a plasticizer may be
due to improper refining techniques, instability in storage, or
A suitable procedure is ASTM Method D 1613, Acidity in Volatile
Chemical Intermediates Used in Paint, Varnish, Lacquer, and Related
The sample is mixed with an equal volume of alcohol (ethyl or
titrated with aqueous sodium or potassium hydroxide to the phenol
point. The test results may be expressed as percent by weight as acetic
acid number (milligrams potassium hydroxide consumed per gram of
sample) or, if
the acid used in preparing the ester is known, as percent of that acid.
presence or absence of
color is an indication of the
degree of refinement or cleanliness of the shipping or storage
Plaslicizers in general are essentially colorless, but polymeric
may have the appearance of a light molasses. The usual method is
with platinum cobalt standard solutions.
plasticizer must be
completely miscible with the resin or plastic component(s) after drying
lacquer on the substrate. Test by adding plasticizer to the lacquer
an amount equal to the base resin. If the dried film remaining on a
after evaporation of the solvent is not clear and transparent, repeat
with reduced amounts of plasticizer until a transparent film is
or solid exudates should not be present on the surface of the film.
This is a
go no go measure of compatibility and is convenient for initial
the plasticizer. In selecting a plasticizer for use in a lacquer, it is
remember that permanence of the mixture on the substrate may be
the conditions of ultimate exposure, including temperature, effect of
(UV), humidity, and other components in the formulation.
is applied normally
to hydrocarbon solvents and is a visual estimate of the presence of
combined sulfur. Some types of plasticizers, that is, sulfonic acid
derivatives, should be evaluated for degree of discoloration.
property may be affected
by improper refining techniques, impurities inherent in the sample, or
contamination. Atmospheric distillations are made according to ASTM
1078, Distillation Range of Volatile Organic Liquids, or ASTM Method D
Distillation of Petroleum Products. The high temperatures involved may
decomposition, and more significant values may be obtained by
distillations under vacuum as low as 5 mm. This is a critical property.
quantities of impurities
often impart electrical conductance to otherwise high resistance
The electrical insulating qualities are measured by d c resistivity and
power factor. The procedure for the former is to be found in ASTM
Method D 257,
Electrical Resistance of Insulating Materials for the latter in ASTM
150, A C Loss Characteristics and Dielectric Constant (Permittivity) of
Electrical Insulating Materials.
of the large volume
plasticizers are esters, this test may be used to estimate purity. The
remaining portion of the sample usually is the alcohol associated with
original reaction to produce the ester. The preferred test is described
in ASTM Method D 1617, Ester Value of Lacquer Solvents and Thinners.
is saponified with an excess of 0.5 N potassium hydroxide (KOH) in a
bottle immersed in a bath of boiling water. The excess alkali is
standard sulfuric acid, and the percentage of ester is computed from
Method D 92, Flash and
Fire Point by Cleveland Open Cup, is commonly used. Test results are
by improper refining or by contamination with low boiling material.
refractometer is used,
but the Pulfrich refractometer is also satisfactory. For details, see
Method D 1218, Refractive Index and Refractive Dispersion of
Liquids, or directions accompanying the instrument being used. This is
precise test and may be used as an identifying test and to indicate
be influenced by
improper refining or by contamination. The usual test is ASTM Method D
Since plasticizers are relatively nonvolatile, odor is noted after the
saturated filter paper strip has drained for 5 min.
samples are a
prerequisite for the evaluation of plasticizers. If familiarity with
plasticizer permits, ASTM Method D 1045, Sampling and Testing
be used. Otherwise, the more elaborate ASTM Recommended Practice E
Sampling Industrial Chemicals, should be used.
rather than freezing point, distinguishes industrial grade material
high purity material otherwise inferred. The temperature at which
solidification occurs relates in part to retention of solubility in,
the dry lacquer film. ASTM Method D 1493, Solidification
Point of Industrial Organic Chemicals, should be used. Since
low as 70 C will be encountered, ASTM E 1, Specifications for ASTM
Thermometers, should be consulted for thermometers to use. For such low
temperatures a denatured alcohol dry ice bath, or equivalent, will be
provides a means of
identification, where used in conjunction with other tests, but is
impurities. The hydrometer or the pyconometer methods may be used.
is a measure of the
flow characteristics of the plasticizer at various temperatures. The
viscometer is preferred to efflux or other rotational types because of
ready adaptability to all temperatures or viscosities likely to be
in general may
absorb small amounts of water, and this could have an adverse effect on
lacquers containing hydrocarbon solvents both in the liquid form and on
film. The recommended method is ASTM Method D 1364, Water in Volatile
Fischer Reagent Titration Method.
sample is a plasticizer,
preliminary preparation is not necessary. A laquer, however, should be
an amalgamated plate. The film thus prepared as well as scrapings from
already dry lacquer coating should be extracted with hot ethyl ether in
apparatus to isolate the plasticizer. The conditions of ASTM Method D
Acetone Extraction of Phenolic Molded or Laminated Products, are
substituting ether for acetone and conti nuing the extraction for 6 h.
the ether has been evaporated the specific tests are applied to the
plasticizer. If the isolated plasticizer is hazy, mix with several
of ethanol and filter. This treatment removes polymers that may have
soluble in the ether.
is fused with
metallic sodium for the detection of the elements nitrogen, chlorine,
and phosphorus. To a clean, dry. 6 in. test tube supported near the
open end in
a vertical position with a clamp and iron stand, add a 3 mm cube of
metallic sodium. Heat the bottom of the tube until a layer of sodium
vapor 1 cm
deep is formed. Add directly to the vapor 2 to 3 drops of liquid
equivalent amount of lacquer scrapings or dry film may be treated in
manner. Remove the flame immediately. When the tube is cold, break off
with the sodium in a mortar. Add several milliliters of alcohol to
unreacted sodium, then add 20 ml of distilled water and grind coarsely.
Transfer to a beaker, bring to a boil, and filter. The filtrate should
Perform all the above
under a hood using a face shield and avoid contact with water until
5 ml of filtrate add
2 ml of a 10 percent solution of solution hydroxide (NaOH) containing 2
drops of a 10 percent solution of lead acetate. A black precipitate of
sulfide will form if sulfur is present.
Boil for 1 min, 2 ml
of tiltrate, 5 drops of a 10 percent solution of NaOH, and 5 drops of
percent ferrous sulphate solution. Cool, and add 10 percent solution of
hydrochloric acid (HCl), drop by drop, until the solution is acid and
precipitate of ferrous hydroxide has dissolved. Avoid excess acid. A
green color or blue precipitate indicates presence of nitrogen.
Acidify 5 ml of
filtrate with several drops dilutes sulfuric acid (H2SO4)
and boil for several min if sulfur or nitrogen is present. Cool and
with nitric acid (HNO3) and add several drops of 10 percent silver
(AgNO3) solution. A whitish precipitate
indicates presence of
Boil 5 ml of
filtrate with 3 ml of concentrated HNO3 for 1
min. Cool and add
twice the volume of 10 percent ammonium molybdate solution. Heat to
about 60 C
and set aside to cool. A yellow precipitate indicates the presence of
Add about 0.05 g of
resorcinol and 0.05 g of phenol to separate 6 in. test tubes and to
each add 2
to 3 drops of the isolated plasticizer and a drop of concentrated H2SO4
then heat several minutes in an oil bath at 160 C. Cool and add 2 ml of
distilled water and 2 ml of 10 percent NaOH and stir. If phthalates are
present, the tube with resorcinol will show a pronounced green
and the tube with phenol will be red. Sebacates and ricinoleates will
faint greenish fluorescence.
Destructively distill 1
to 2 drops of the isolated plasticizer in a 5 in. test tube and collect
vapors in a second tube containing several mililiters of distilled
and filter. To a portion of the liquid add 1 drop of Miltons reagent
by dissolving 1 part mercury in 2 parts concentrated HNO3
and dilute with 2 volumes of distilled water. Use the supernatant
the test and heat gently. A reddish coloration develops if phenols are
The test may be confirmed by adding to a separate portion of this
several crystals of 2, 6 dibromoquinonechloroimide. Shake and add 1
drop of 10
percent NaOH. A blue streak in the liquid or blue on the edges of the
crystals of reagent indicates phenols. A positive test indicates the
of tricresyl phosphate or other phenolic plasticizer.
quantitative measurement of
plasticizers at the present time is limited to those characterizing
discussed in the qualitative tests. Methods for the estimation of these
components are given next.
obtained are calculated back to structures of known formulas.
suitable procedure is
included in ASTM Method D 817, Cellulose Acetate Propionate and
Acetate Butyrate. Reactions involving perchloric acid are hazardous,
suitable precautions must be observed.
is determined by the
Kjeldahl method as found in ASTM Method E 258, Total Nitrogen in
Materials by Modified Kjeldahl Method, or in ASTM Method D 1013, Total
in Resins and Plastics. The sample is digested in a mixture of
sulfuric acid, potassium sulfate, and mercuric oxide. The organic
oxidized, and the nitrogen is converted into ammonium sulfate. Sodium
is added to the digested mixture to precipitate the mercury after which
solution is made alkaline with strong sodium hydroxide solution and the
that is liberated is distilled into a measured volume of standard acid.
excess acid is titrated with standard sodium hydroxide solution.
The Thompson Oakdale
method appears to be very satisfactory for this determination. The
ASTM Method D 1156, Total Chlorine in Poly (Vinyl Chloride) Polymers
and Co polymers
Used for Surface Coatings, may be followed.
is decomposed in a
special glass apparatus by stepwise treatment with H2SO4, potassium
(K2S2O8), and potassium permanganate (KMnO4). Chloride is converted to
chlorine. The chlorine is absorbed in a sodium arsenite solution. This
is acidified with HNO3 and treated with AgNO3 to
chlorine as silver chloride.
Phosphorus may be determined as directed
in ASTM Method D 1091, Phosphorus in Lubricating Oils and Additives.
methods, photometric and gravimetric, are given, but the latter is
matter is destroyed and
the phosphorus is converted to phosphate ion by oxidation with sulfuric
nitric acid, and hydrogen peroxide. The phosphate ion is then separated
interfering metals by precipitation as ammonium molybdophos phate in
acid solution. The solution is made ammoniacal and the phosphorus is
precipitated as magnesium ammonium phosphate, ignited, and weighed as
ASTM Method D 1652,
Epoxy Content of Epoxy Resins, is available for this determination.
is dissolved in a
suitable solvent, and the resulting solution is titrated directly with
solution of hydrogen bromide in glacial acetic acid. The hydrogen
reacts stoichiometrically with epoxy groups to form bromohydrins
quantity of acid consumed is a measure of the epoxy content.
by Refractive Index
describes a method of
classifying plasticizers by plotting refractive index against density.
narrows the classification by plotting refractivity index against
comparing boiling point against these data he arrives at satisfactory
identifications in most instances.
has tabulated the
fluorescent colors of a number of plasticizers as indicated in Table 2.
perform the test, place a drop of plasticizer on a filter paper and
black light (UV at 3650 A). Perform this test in a dark room.
solvent may be defined as a liquid that is used to bring a solid or
material into a liquid form. The ability to dissolve a material is the
distinguishing characteristic of a solvent, the primary performance
Of nearly equal importance in almost every coatings application is
rate. Direct measurement of these performance properties is not always
or convenient. Other tests, therefore, are used to estimate them. There
other important properties, and tests to measure them, that are not
directly with basic performance. These include safety of handling,
purity, composition, and compliance with air pollution laws.
solvent reduces the coating viscosity to the level required for
The required viscosity, as well as the required evaporation rate,
the end use and the method of application. Evaporation of the solvent
the first and sometimes the only mechanism in drying of the coating. It
first stage in the drying of coatings made with reactive resins that
oxidation or catalytic or heat curing. It is the only mechanism in the
of lacquer type coatings.
that dry by oxidation or heat curing are very often soluble in
solvents made from petroleum or coal tar. In cases where other types of
solvents are used, the possible participation of the solvent in the
must be considered. For lacquer type resins, which dry by solvent
there are three solvent constituent types: active, latent, and diluent.
active solvent is a true solvent for the resin. A latent solvent alone
dissolve the resin but becomes a solvent or has a synergistic effect
blended with an active solvent. A diluent has no solvency for the resin
tolerated by it in blends and is added to reduce cost and sometimes
solvent does not remain permanently in a coating film, but its effects
apparent in the film. Leveling and sagging are apparent for the life of
coating, but they can be controlled by proper choice of solvents. In a
the solvent initially imparts the proper flow and usually is a factor
thickness of the film that can be applied. As the solvent evaporates,
viscosity of the film increases, and this, in turn, affects the
manifests itself in two ways: (a) by the miscibility of a solvent and a
and (A) by the efficiency of a solvent in reducing resin viscosity.
is usually detected visually. Lack of miscibility creates layers of
do not blend a cloudy solution, or a solid precipitate. The best method
choosing solvents that are miscible with resins is to use solubility
scientific system has been developed for selecting the solvent or
combination for a given coating requirement. This is based on solubility
parameter, which is a numerical constant characteristic for
and film forming material. The small Greek letter delta is used to
these values which are single numbers for solvents, whereas it is more
convenient to designate a range of values for resins or polymers.
the value for a liquid lies within the range designated for the film
that liquid will be a solvent for the film former. Thus, a simple
numbers is all that is required to predict solubility. It is necessary,
however, to introduce one other factor in order to make accurate
namely, Hydrogen bonding.
may be grouped into three classes according to their hydrogen bonding
I Poorly Hydrogen Bonded Solvents: includes aliphatic, aromatic,
and nitro hydrocarbons.
II Moderately Hydrogen Bonded Solvents: includes esters, ketones,
III Strongly Hydrogen Bonded Solvents: includes alcohols, amines, and
is customary to specify the solubility parameter ranges for the film
each of these classes. As may be seen in Table 1, individual resins may
soluble in different numerical ranges in any one or more of the
for Solvents Solubility
can be calculated in a variety of ways. A simple method uses the latent
vaporization and density. Hoy examined solvent parameters based on
pressure. Values have been already calculated for most solvents, and
available listing them in alphabetical, numerical, and boiling point
abridged set of values for common solvents appears in Table 2.
for Film Formers Since it is usually
impossible to volatilize a
polymer, values for film formers must be obtained indirectly. A
method for determining ranges is the following:
gram or two of solid polymer is placed in a test tube, and an
amount of a selected solvent is added such that the final solution
about the correct solids content for the expected commercial use, for
50 percent for alkyds, 20 percent for vinyls, etc. The exact amount is
unimportant except for poor solvents it should be kept in mind that
are usually miscible in concentrated solutions, although they may form
phases in dilute solution. The mixture may be warmed and stirred to
solution, but it should be cooled and observed at room temperature. The
resulting mixture should be single phase, clear and free from gel
cloudiness or else the polymer is judged insoluble. The solvents to be
selected from the Solvent Spectra, Table 3.
a group of solvents has been especially selected so that the values
reasonably constant steps within each H bonded class. The object of
solvent spectrum is to establish a solubility parameter range for a
rather than a single valued number. This has the advantage of
showing the allowable difference that can be tolerated between the
values of the polymer and solvent. In carrying out the procedure it is
convenient to select the first trials about one third and two thirds of
down any one column for example, in the poorly H bonded group toluene
nitroethane would be chosen. If the polymer is soluble in both, there
need to try intermediate solvents because experience (as well as
shown that the polymer will be soluble in every case instead the
the ends of the spectrum should be tried next. If the polymer was
one but not both of the initial trials, the third trial should be about
between the two. By successive choices sets of two adjacent solvents
found, one of which dissolves the polymer and one of which does not.
parameter values of the solvents which do dissolve the polymer mark the
the range. The procedure is then repeated for the other two H bonded
Some values for typical resins may be found in Table l, and a more
for Mixed Solvents The
correct method for calculating the value for a mixture of solvents is
in Ref 1, but for most purposes the average value of the components
percent composition by volume is sufficiently accurate. The same is
in a general way for hydrogen bonding, that is, a mixture of toluene
hydrogen bonded) and ethanol (strongly hydrogen bonded) will tend to
like Cellosolve (moderately hydrogen bonded). In critical cases where
average value of a solvent mixture is near one end of the range for a
former, the mixture may not be as good as a single solvent. Where the
components of a mixture are nonsolvents by themselves, it is advisable
5 to 10 percent of additional true solvent present.
to Use Solubility Parameter Data
l and 2 can be used to select solvents for the film formers listed. For
example, Acryloid B 44, which has a poorly hydrogen bonded range of 8.9
11.9, would be soluble in the following typical solvents listed in
Table 2: acetonitrile
(11.9), acrylonitrile (10.5), but not in apcothinner (7.8), etc. and in
moderately hydrogen bonded range of 8.5 to 13.3 in acetone (10.0), n
acetate (8.5) but not sec amyl acetate (8.3), etc. A zero value for
Acryloid B 44
in the strongly hydrogen bonded column indicates that it is not soluble
strongly bonded solvent.
other considerations such as cost, availability, odor, toxicity,
etc., will determine the final solvent selection, but using solubility
tables greatly narrows the choice down to those that will indeed be
are likely to be nonsolvents chosen because of their low cost. The
diluent nonsolvent permissible can be estimated by calculating the
value of a mixture with true solvent that will still lie within the mid
percent of a given film former range. The amount of diluent can often
increased by using a latent solvent which should be selected near the
the solubility parameter range opposite from the diluent so that the
values fall near the midpoint of the range.
of the most important aspects of solvent choice is viscosity.
parameter has no direct relationship to viscosity except that 6
near the extreme ends of film former ranges may produce high
primary factor effecting viscosity control is the viscosity of the
itself. Low viscosity solvents will produce low viscosity solutions and
versa. This factor may be correlated with solubility parameter by
a chart such as Fig. 1 where viscosity of solvents is plotted against 6,
data such as volatility may be included by showing shaded circles. If
desired to lower (or raise) the viscosity of a given solution,
determine the value
for the solvent present and then
replace it with a solvent selected from the chart which has a lower (or
of the Solubility Parameter Concept Many
illustrating the use of solubility parameter are given plasticizers
be chosen by considering them as nonvolatile solvents. Solvent
be obtained by selecting a film former from Table 1 which shows a range
removed as possible from the value of the solvent
which must be
resisted. Solvents for organosols should be
formulated just outside the
range of solubility. Swelling of applicator rolls,
blankets, etc., can be handled by using Table 3 to determine the values
at which maximum swelling occurs, then formulating paints or inks with
differing as much as possible from those values. Compatibility
of two or
more film formers can be assured if they are selected such that the
of the ranges do not differ by more than one unit.
reduction is determined by measuring the viscosities of solutions of
concentrations of a given resin in the solvent and plotting the
versus the resin concentration. This type of plot is shown in Fig. 2.
solvents, even though they may be miscible with the resin, will give
with different slopes. At high resin concentrations, solution viscosity
depend upon the solvency of the solvent and the solubility of the
resin. At low
resin concentrations, the solution viscosity is proportional to the
viscosity. An extreme case is shown in Fig. 3. The data show
viscosities of 50
percent solutions of a medium oil alkyd resin in blends of VM&P
with isobutyl alcohol and the same VM&P naphtha with n butyl
Isobutyl alcohol has a high viscosity but is a strong solvent for alkyd
The resin solution in isobutyl alcohol has a relatively high viscosity.
VM&P naphtha percentage in the solvent is increased, the
even though the true solvency is decreasing. This is because the
the solvent portion is decreasing. As the percentage of the
VM&P naphtha is
increased above 50, the viscosity of the solution increases because the
is becoming weaker, that is, its ability to solvate resin molecules is
decreasing. The n butyl acetate has a relatively low viscosity, and
of the resin solutions increase as the VM&P naphtha is added to
of a medium oil alkyd and a bodied linseed oil in toluene and in iso
shown in Fig. 4. The linseed oil is very soluble, and the difference in
solvency between the toluene and isooctane are less important than in
of the medium oil alkyd. Also, the viscosities of the solutions remain
low at a
higher linseed oil concentration.
of resin solutions can be measured precisely by ASTM Method D 445,
Transparent and Opaque Liquids. ASTM Method D 1545, Viscosity of
Liquids by Bubble Time Method is a simpler, less precise, but more
method for determining viscosity reduction, and for viscosities of
point is one of several methods for estimating solvency that are based
correlation with some observed phenomenon. It is used only for
thinners having aromatic hydrocarbon contents of less than about 50
The aniline point is the lowest temperature at which equal volumes of
and the thinner will mix and give a clear solution technically this is
the critical solution temperature. A low value indicates high solvent
vice versa. The test is run by mixing 10ml of thinner with 10ml of
aniline in a
jacketed test tube. The solution is stirred continuously during the
the mixture is initially cloudy, it is warmed until it becomes clear.
mixture is initially clear, it is cooled
until it becomes cloudy. The aniline point is the temperature at which
transition occurs. Mixed aniline point is a test for estimating the
power of high aromatic petroleum solvents. It is similar to an aniline
except that the sample is mixed with an equal volume of n heptane
testing this blend is then tested with an equal volume of aniline. The
test mixture thus contains 5 ml of the sample, 5 ml of n heptane, and
10 ml of
aniline. The modified procedure is necessary because aromatic solvents
aniline will form clear, homogeneous mixtures to temperatures as low as
freezing point of aniline. The n heptane raises the cloud point of the
and permits the estimation of the relative solvent power of aromatic
Again, a low value indicates high solvent power and vice versa. A
of aniline point and mixed aniline point is that the two scales are not
continuous. It is, therefore, difficult to compare solvencies of high
and low aromatic
Method D 611, Test for Aniline Point and Mixed Aniline Point of
Products and Hydrocarbon Solvents, and ASTM Method D 1012, Aniline
Mixed Aniline Point of Hydro carbon Solvents, describe similar and
methods for determining the aniline points of petroleum solvents. The
equipment. It is sometimes a temptation, particularly since the advent
pollution laws, to use aniline point to estimate the solvency of blends
hydrocarbons with other types of solvents. This should not be done
aniline point has no systematic correlation with solvency for materials
butanol value is an alternate to aniline point for estimating solvency
hydrocarbon thinner. It has the advantage that it is a continuous scale
from a low of about 26 for odorless mineral spirits to 105 for toluene.
procedure is described in ASTM Method D 1133, Kauri Butanol Value of
Hydrocarbon Solvents. The kauri butanol value of a solvent is the
solvent in milliliters required to produce a specified degree of
added to 20 g of a standard solution of kauri resin in normal butyl
20 g of standard kauri resin solution is weighed into an Erlenmeyer
placed in a water bath. It is titrated with the solvent being tested
sharp outlines of 10 point print on a sheet placed under the water bath
through the liquid are obscured or blurred but not illegible. The
caused by precipitation of the resin.
butanol value, as aniline point, is not suitable for evaluating any
ratio is important in formulating lacquer solvents. ASTM Method D 1720,
Dilution Ratio in Cellulose Nitrate Solutions for Active Solvents,
Diluents, and Cellulose Nitrates, describes the procedures. The ratio
to butyl acetate
that will be tolerated by a solution of 8 g of nitrocellulose in a
total of 100
ml of solvent and diluent gives a measure of the suitability of
the diluent for use in lacquer solvent
the ratio of toluene as the standard diluent to an oxygenated solvent
same conditions gives a measure of the suitability of the oxygenated
portion as a lacquer solvent. Variations in the cellulose nitrate can
explored using butyl acetate and toluene as standard solvents.
objective in formulating a lacquer solvent is to produce a lacquer with
viscosity and a low cost. It is, therefore, desirable to use the
percentage of diluent that can be tolerated by the nitrocellulose and
will give the desired performance. The dilution ratio test provides a
achieving this goal.
procedure is to dissolve the nitrocellulose in the true solvent and
diluent by titration. The end point occurs when resin precipitates or
appears. Additional true solvent is added, and the titration is
are plotted to determine the ratio of diluent to true solvent at
exactly 8 g of
cellulose nitrate per 100 ml of volatile matter.
resins are soluble at high concentrations in a solvent but precipitate
diluted below a critical concentration. Often this concentration is
range of practical formulations. Thus, it is important to know the
limits of resins.
determine dilution limit, a known weight of resin is dissolved in the
Solvent is added until precipitation occurs. Toward the end of the
determination, cloudiness will occur, and solvent should be added in
increments. The end point is reached when the cloudiness becomes
Dilution limit is expressed as the percent by weight of solids at the
concentration. These determinations should be made at a standard
rate of a solvent is second only to solvency in its importance in the
industry. Solvent evaporation controls the setting time of all coatings
drying time of lacquer type coatings. The solvent must remain in the
enough to allow flow sufficient to produce satisfactory adhesion,
gloss, and leveling
it must evaporate fast enough to prevent sagging and inadequate film
There are few paint properties not affected by flow and thus by solvent
relationship between evaporation rate and solvency is always critical
blends of different molecular types. Constituents rarely evaporate at
rate therefore, the composition and resulting solvency change as the
evaporates. Film properties can vary widely because of this phenomenon.
evaporation rate is not an absolute value in practical situations
depends upon environmental conditions. Temperature, air movement, the
of a solute, surface area, and sometimes humidity are factors that
evaporation of a single solvent. Most evaporation rate data, therefore,
relative. One solvent is compared against another under the same
pressure is the fundamental property controlling evaporation rate. If
solvents were pure compounds and environmental conditions could be
evaporations rates would be proportional to vapor pressures. Vapor
the pressure exerted by the molecules of vapor in equilibrium with
which in turn is a measure of the escaping tendency of the molecules.
pressure is not often used to describe the evaporation rates of
may be partly because vapor pressures are difficult and tedious to
precisely. One basic technique involves a differential manometer. One
the manometer is exposed to saturated vapor, while the other is
Extreme care must be taken that no air is present. Another basic
to control the pressure and measure the boiling temperature. At this
temperature, the vapor pressure is equal to the applied external
third method is to bubble dry gas through the liquid in such a way that
becomes saturated with vapor. Then the gas stream is analyzed, and the
pressure of the compound in the gas is the vapor pressure.
solvent blends or petroleum thinners, vapor pressure cannot be used
because the composition and, therefore, the vapor pressure changes as
pressure varies markedly with temperature, as shown by the data in Fig.
These data show also that the rate of change of vapor pressure with
is different for different molecular types, For all materials, the
point is defined as the temperature at which the vapor pressure equals
of mercury or atmospheric pressure.
Rates by Electrobalance
Chevron Research Company Evapograph is essentially a recording balance
A 6 in.2 piece of blotter card backed
foil is suspended by a fine wire from a strain gage. The solvent to be
is dispensed onto the blotter card with a hypodermic syringe. During
a Petri dish containing the same solvent is placed so that the liquid
approximately ¼ in. below the blotter. The blotter is, therefore, in
space above the liquid reservoir. The sides of the Petri dish keep the
stream from flowing across the specimen. Under these conditions,
evaporation occurs during the charging step. The recorder is adjusted
the pen is on the baseline of the chart. The test is started by
Petri dish so that air flows across the specimen. Air enters through a
2 by 4 in.
bundle of 3 mm inside diameter glass tubes to create laminar flow. The
is 20 liters per minute. The temperature
of the evaporation chamber is controlled at 80 F. Relative humidity can
varied from almost zero to almost 100 percent. As the specimen
weight is recorded on the chart as a function of time. Typical data are
in Fig. 7, where weight percent evaporated is plotted as a function of
Precise, repeatable measurements can be made over a wide range of
Hexane requires about 6 min for total evaporation kerosine requires
days. Evaporation of solvents from resin solutions can be also studied
are not too viscous. Resin retards the evaporation of a solvent.
for a solvent evaporating from an alkyd resin are shown in Fig. 8
Shell thin film evaporometer is also a recording electrobalance for
the evaporation rate of solvents. A filter paper, 9 cm in diameter, is
suspended in the evaporation chamber from an electronic optical weight
device. The sensing device and evaporation compartment are encased in a
cabinet which is insulated to assist in maintaining uniform
charging a sample, the recording pen is adjusted to the baseline.
added from an hypodermic syringe and distributed over the entire area
filter paper. Sample size is 0.70 ml, which should be added within a
10 s. Some evaporation may occur during this time. However, it is
only for fast evaporating solvents and in any case can be compen sated
extrapolating the recorder chart after the run is completed.
Temperature in the
evaporation chamber is controlled at 77 F relative humidity is
less than 5 percent, and air flows through the chamber at a rate of 21
per minute. Data are usually reported as time in seconds at 10 percent
increments through the evaporation cycle. The Shell thin film
Acetate Evaporation Standard
has become common practice to use the evaporation rate of n
acetate as a reference standard. This compound is arbitrarily assigned
of 1. 0 or 100, depending upon the scale being used. Those materials
evaporating faster than butyl acetate have larger evaporation rate
solvents evaporating slower than butyl acetate have lower numerical
This comparison procedure is used with a variety of evaporation rate
When an electro balance is used for the evaporation measurement, the
90 percent of the sample to evaporate is used frequently as the
point. Sometimes the specimen and butyl acetate are simply evaporated
side from evaporating dishes. Use of a reference standard compensates
differences in procedure or environmental factors. Some values are
Table 4 in comparison with that for n butyl acetate.
Evaporation Rate Methods
evaporation rate determinations were simple. A known quantity of
put in a dish or spread on a piece of filter paper and the loss of
obtained at regular intervals. Weighings were made on an ordinary
balance or on special balances. Various types of dishes have been used
including friction top can lids and Petri dishes. Bridgeman suggested
bottoms flat on the outside but dished on the inside. Rubek and Dahl
small metal tripod to hold the paper flat against the bottom of a can
chromatography, which is described is particularly useful for
aromatic contents of hydrocarbon thinners and solvents. These analyses
performed usually with silica gel in a glass tube. The sample is
the tube with an alcohol and separates into molecular types as it
downward through the column.
Method D 1319, Hydrocarbon Types in Liquid Petroleum Products by
Indicator Adsorption, uses the equipment shown in Fig. 14. A capillary
a separator section, and a portion of the reservoir section are filled
200 mesh silica gel. A fluorescent dye is either added to the liquid,
section of dyed gel is included in the charger section. Approximately
of specimen is introduced at the top of the column. The reservoir is
with isopropyl alcohol. Air pressure is applied to force the liquid
tube. The alcohol, being the most strongly adsorbed, pushes the
of it. Molecular types in the specimen are separated as the liquid
through the tube. Paraffins and naphthenes are the least strongly
travel farthest down the capillary column. They are followed in order
olefins and aromatics. Portions of the fluorescent dye make the zones
under ultraviolet light. Paraffins and naphthenes are colorless but
because the adsorbent is wet. Olefins fluoresce a chartreuse color.
fluoresce a violet color. When all of the specimen is in the capillary
lengths of the sections are measured and are proportional to the volume
percentages of the hydrocarbon types.
modification by Ellis and LeTourneau extends this method to the
of the total oxygenated portion of lacquer thinners. The modification
an additional dye component and substituting n
butyl amine for the
isopropyl alcohol to displace the sample down the column.