Rubber products industry is an important resource based industry sector in India. Over the last decade the rubber industry has witnesses a steady and strong growth. Rubber exhibits unique physical and chemical properties. Rubber's stress-strain behavior exhibits the Mullins effect and the Payne effect, and is often modeled as hyperelastic. Rubber strain crystallizes. Owing to the presence of a double bond in each repeat unit, rubber is susceptible to vulcanisation and sensitive to ozone cracking.
The two main solvents for rubber are turpentine and naphtha (petroleum). The former has been in use since 1764 when François Fresnau made the discovery. Giovanni Fabbroni is credited with the discovery of naphtha as a rubber solvent in 1779. Because rubber does not dissolve easily, the material is finely divided by shredding prior to its immersion.
Rubber particles are formed in the cytoplasm of specialized latex-producing cells called laticifers within rubber plants. Rubber particles are surrounded by a single phospholipid membrane with hydrophobic tails pointed inward. The membrane allows biosynthetic proteins to be sequestered at the Surface of the growing rubber particle, which allows new monomeric units to be added from outside the biomembrane, but within the lacticifer. The rubber particle is an enzymatically active entity that contains three layers of material, the rubber particle, a biomembrane, and free monomeric units.
The monomer adds to the pyrophosphate end of the growing polymer. The process displaces the terminal high-energy pyrophosphate. The reaction produces a cis polymer. The initiation step is catalyzed by prenyltransferase, which converts three monomers of isopentenyl pyrophosphate into farnesyl pyrophosphate. The farnesyl pyrophosphate can bind to rubber transferase to elongate a new rubber polymer.
The major contents of this book are project profiles of projects like Processing of Crude Rubber, Latex Rubber Foam Products, Rubber Floor Mats, Latex Rubber Threads, Rubber Compounding for Automotive Industry, Rubber Gaskets, Reclaim Rubber, Rubber Powder from Waste Tyre, Carbon Black from Waste Tyre Pyrolysis, Equipments used in Rubber Industry.
Project profile contains information like; Introduction, Uses and Applications, Properties, Manufacturing Process, Plant Economics, Rated Plant Capacity, Plant & Machinery, Fixed Capital, Raw Material, Total Working Capital, Cost of Project, Total Capital Investment, Turn Over/ Annum, Profit Sales Ratio, Rate of Return, Break Even Point (B.E.P).
This book is very useful for new entrepreneurs, technical institutions, existing units and technocrats etc.
rubber foam products
defined as the stable dispersion of natural rubber particles in aqueous
as produced in the rubber tree. They are complex colloid systems
polymer molecules as major fraction. The polymer may be a homo polymer
co-polymer .Stereo regularity and the complexity of the polymer
(linear / branched / cross linked) is maintained in the latex form.
are rubbery or resinous in nature and the rubber molecules can be cross
Lattices can be plasticized or oil extended. Lattices have their own
properties and temperature limits of serviceability. Latex products are
to degradation and adequate antioxidant protection is necessary. They
classified broadly into four main types: natural, synthetic, artificial
modified latices. In Natural lattices large number of plant species
lattices containing polyisoprenes, but only Hevea braziliensis latex is
industrially important. In á Synthetic lattices with the rapid growth
polymer chemistry since 1940, a large number of synthetic lattices are
available commercially. Artificial lattices are the dispersions of
rubber, butyl rubber or other polydiene rubbers. They also include
by solution polymerization and conversion of the polymer solution into
Modified lattices are produced by the chemical modification of the
types. For e.g., controlled vulcanization of the rubber in latex would
modified latex generally known as the prevulcanized latex. Natural
(NR Latex) is the most widely used latex for the manufacture of latex
rubber products. Natural rubber (NR) processing sector is an industry
produces raw materials used for the manufacture of rubber industrial
(conveyor belts, rubber rollers, etc.), automotive products (fan belts,
radiator hoses, etc.), latex products (rubber gloves, toys hygienic
etc.) and many kinds of adhesives. The major users of natural rubber
and footwear industries.
Latex is a
rubber particles in an aqueous phase. Most types of rubber, both
synthetic, can be made into a latex form. Latex gets used in
applications such as those requiring oil, solvent or flame resistance.
Different mixing techniques produce different grades of dispersions
milling or ultrasonic’s for fine particle dispersions and simple
colloid milling for coarse dispersions. Latex dipping is used to make
articles such as gloves, balloons, catheters, bladders; hot water
and very fine particle dispersions are needed. Coarser particle sized
dispersion (slurry) is acceptable for latex foam, used mainly for
backing. The following range of additives can be mixed with the latex
dispersion or emulsion:
Stabilisers: to maintain the
rubber particles in a
stable state of suspension. These include sulphonates, inorganic
phosphates and soaps.
dithiocarbamates, thiazoles, thiurams, and xanthates.
glue, cellulose derivatives.
waxes, substituted phenols, amine based antioxidants.
ammonia, sodium and potassium hydroxide, and formaldehyde.
mostly halogen derivatives, for suppression of bacterial decay and
and gelling agents,
include calcium, magnesium and aluminum salts, acetic and formic acid,
acetate and ammonium acetate.
uses a porcelain or aluminum mould (or former) that is repeatedly
dipped in the
latex compound. Once set, the coated former is washed, air-dried and
in steam autoclaves before the product is removed. To increase the
the deposit obtained per dip, the former is immersed in coagulant
after each latex dip.
casting is a similar technique to dipping but is used to make hollow
articles. The product forms on the inside of the mould (in contrast to
giving a better surface definition. This process is uncommon.
mixing plant and processing equipment such as carpet backing machines,
present a range of mechanical hazards that will require effective safe
by the latest available techniques..
The process of
removal of substantial quantity of serum from the latex and increases
rubber content to about 60%. In creaming process, a creaming agent
seed powder) is added and allowed to remain undisturbed till the
of creaming (concentrated rubber) is obtained. In Centrifuging, the
subjected to centrifuge force in a bowl rotating at speed around 6,000
surrounding the axis of rotation.
rubber latex pillows, mattresses, cushions, bedding etc. are used in
purposes. The latex foam mattresses are used for manufacturing of
automobiles, cars, tempos, buses, jeeps, aero plane, etc. In hotel some
the floor mat are also used
Bed Pillows this item has been widely accepted. They are produced by a
number of the accepted shape used for feather or down pillows, they are
generally very soft, but not flabby, retain their shape without
are particularly advantageous for allergy sufferers.
Pillows are comparatively new application for foam, but is being
enthusiastically by the buying public.
Furniture Cushions is very popular in the furniture field. A similar
application is non-reversible furniture seats and backs, airplane, bus,
Its application is the largest latex volume consumer. They are widely
hospitals where they permit maximum comfort with minimum replacement
permit maximum comfort with minimum replacement.
Pads. The automobile producers are the largest users of foam rubber in
number of pieces used. Foam rubber topper pads are now considered
equipment in most automobiles.
Products. Latex foam slab is frequently combined during processing with
other materials. A layer of ungelled foam can be deposited directly to
of a rug, sheeting, upholstery fabric, curled hair and similar types of
materials for use as under carpet padding, ironing board padding,
materials, etc. Applications in this field are limited only by one’s
foam rubber recovered as manufacturing scrap or recovered from post
use can be chopped and utilized when mixed with polyurethane scrap, as
foam is suitable for disposal via municipal landfill or incineration in
states and municipalities.
foam rubber derives its physical performance properties from the
process that creates long molecular chains with strong cross linked
foam rubber generally has a relatively high density and is soft, thus
foam rubber can only be used in limited amounts in the production of
Foam Producers has a high level of grip, some others are designed to
mattresses are naturally therapeutic and provide extraordinary
Thermal Qualities Latex’s thermal properties are truly outstanding. Its
superior cell structure gives it maximum breath-ability.
latex products: Mattresses, Pillows, Upholstery, Carpet Backings,
latex products: Surgical gloves, House hold gloves, Industrial gloves,
Contraceptives, Feeding Bottle teats, Toy balloons etc.
extrusions: Latex thread.
spreading: Carpet backing, Textile treatment, Paper Coatings.
castings: Toys, Bulbs.
Rubberized coir /fiber products, Battery Separators, Adhesives and
two modern routes to latex foam products concern the way in which the
processes used today on such a large scale for the production of latex
goods, uses for most of the part, a concentrated natural rubber latex
prepared by one of the processes involving partial removal of the
substances as well as concentration of the rubber (e.g. processes such
centrifugation or creaming). Successful operation of latex foam
normally demands a concentrated latex one containing a minimum content
latex, during compounding, to a Valve between 0.1% and 0.25%. This
gelatin and to control the process which is usually done by stirring
blowing a current of air over the surface of the compounded latex as
the “Maturing process”.
Foaming agents are used in a wide range of applications in plastics and
processing. By choosing the right foaming agent system following
could be achieved.
Material and Cost Saving
foaming agents decompose during processing in a chemical reaction which
induced by heat. The decomposition can be exothermic or endothermic.
Latex foam products are cellular (open cell, closed cell or a
open cell and close cell structures) products directly produced from
latex compounds. The skin is a smooth surface formed by contact with
surface. Since Latex foam has an open cell structure because of this
interconnect cell it is spongy in nature.
rubber (NR) latex is a natural commodity that has tremendous economic
strategic importance. Among the applications of NR latex is the
dipped goods, extruded threads, and adhesives, carpet-backing and
foams. This is primarily because of the unique characteristics of NR
such as high strength, flexibility and elasticity. Most NR latex
derived via a sulphur vulcanization system, which achieves the desired
properties for the product application.
latex foam rubber is not flexible polyurethane foam. Synthetic latex
rubber represents a group of materials manufactured using methods
natural latex foam rubber on the same processing equipment.
foam rubber can be the
product of natural rubber suspension and rubber substitute blends, or
it can be
produced using a totally synthetic process such as used to produce
styrene-butadiene rubber (SBR) and polymerized chloroprene, known as
Process of Latex
(Rubber) Foam Products
Basic Raw Material
olaste soap solution.
diethyl dithiocarbamate Dispersion
salt of mercapto benzothizole Dispersion
Silico Fluoride Dispersion
Potassium olaste soap solution
diethyl dithiocarbamate Dispersion
salt of mercapto benzothizole Dispersion
50% of anti
Zinc Oxide Dispersion
Sodium Silico Fluoride Dispersion
(Foaming) to a desired volume.
(Gelling) the rubber particles and
are mainly two methods of making Latex Foam, namely
typical Formulations for the Dunlop process for making Foam is listed
NR Latex (Deammoniated)
Potassium Olaste Soap Solution
Zinc Diethyl Dithiocarbamate Dispersion
Zinc Salt of Mercapto Benzothizole Dispersion
of Anti Oxidant Dispersion
Zinc Oxide Dispersion
Sodium Silico Fluoride Dispersion
then Sulphur, Accelerator, Antioxidants and fillers (in the form of
are added to it in a mixing tank, fitted with a slow speed stirrer. The
compound is then allowed to mature by keeping it slowly stirred for
Sodium Silico Fluoride is sparingly soluble in water but hydrolyses in
hydrofluoric acid and silicic acid.
Na2SiF6 ----------------à 2Na++SiF6–
SiF6— + 4H2O
----------------à Si(OH)4 +
acid alone is not the cause of gelling as gelling is found to occur at
Ph. The silicic acid formed also plays a vital role in gelling.
In the batch
planetary mixer is used for foaming. The mixer is provided with a wire
which rotates in a planetary motion at about 200 rpm. The Latex
weighed out into the mixer bowl; soap is then added and whipped into
rotating cage beater. Beating time normally varies 15 to 20 min when
mix increases from four to six times. The Zinc oxide and the secondary
agent are added, followed by Sodium Silico Fluoride. The foamed
then poured into the mould.
In the Continuous
a frothing machine known as Oakes Frother is normally used. In the
is injected into a stream of latex forming coarse foam which is forced
a toothed rotor and stator plate to refine foam. The Gellant is
in the Frothing stage. Foam is conducted through a hold to the mould.
speed is adjustable for optimum foaming.
For manufacture of large blocks of Foam Rubber moulds are
with metal pins for better heat transfer and easy removal of the
gelling agents (gellants), forming a gel, dissolving in the liquid
phase as a
colloid mixture that forms a weakly cohesive internal structure. Others
mechanical thixotropic additives with discrete particles adhering or
interlocking to resist strain.
be used when medical condition such as Dysphagia causes individuals
Vulcanization: Moulded foam
products are normally
cured by open steam (at 100°C (like carpet under lays) can be cured by
Working: Vulcanized foam
is stripped off from
the mould and worked in water by passing the product between the
the surface of water bath. Excess water is then removed by passing
Drying: The worked
products are dried in the
hot ovens at 60-80°C temperature. Heavier foam grades need longer
shorter curing, then the lighter slabs.
Process utilized hydrogen peroxide to generate oxygen for expansion. A
development uses Oakes type Mixer. Partially Foamed Latex compound is
into the mould where foaming is completed by vaccum. The foamed latex
chilled and gelled by passing carbon dioxide gas. Curing is done by hot
impingement or suction dryers. But this type of plant requires very
carry loads depending on the density of the foam. It can absorb energy
vibrations, also acting as a sound insulator. In mattresses and
does not require dusting or mechanical rearrangement: natural rubber
is also known to have bactericidal properties.
rubber latex, SBR latex yields foam of lower tensile, strength and
at break. The hot tear is also poor, making the removal of the cured
the mould difficult. Therefore, SBR latex is rarely used alone but is
blended with NR Latex.
(RUBBER) FOAM PRODUCT
1 per day
Mixing Machine Made by SS for slow
mixing & compounding of Latex with complete accessories.
for Setting of Latex Foam
Chamber with automatic temp.
Control and all accessories.
Tank SS with Complete accessories
Machine with Rubber Rolls
Turnnel Type with automatic heating and air blowing system
Machines like Valves, Motors, pipes & Fittings etc.
M B T
& ETP Chemicals
TOTAL FIXED CAPITAL
TOTAL FIXED CAPITAL
TOTAL WORKING CAPITAL FOR 3 MONTHS
By Sale of Latex (Rubber)