Rubber technology A

SUMMRUBBER

TECHNOLOGYWritten & Edited by Subrata Das (M.Tech,Polymer)

In this paper I have tried a very brief knowledge sharing about the Rubber

Technology. One thing we have to remember that the Rubber Technology is

vast subject.

SUMMARY ON RUBBER

TECHNOLOGYWritten & Edited by Subrata Das (M.Tech,Polymer)

Subrata Das

4/10/2014


Technology. One thing we have to remember that the Rubber Technology is

RY ON

TECHNOLOGY Written & Edited by Subrata Das (M.Tech,Polymer)


Technology. One thing we have to remember that the Rubber Technology is a very

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CONTENT

Introduction ................................................................................................................................... 2

Rubber materials ........................................................................................................................... 3Ethylene Propylene Rubber (EPDM/EPM) .................................................................................... 3Nitrile rubber (NBR) .................................................................................................................... 3Natural Rubber (NR) ................................................................................................................... 3Styrene - Butadien Rubber (SBR) ................................................................................................ 3Chloroprene rubber (CR)............................................................................................................. 3Silicone (VMQ/MVQ/HTV) ........................................................................................................... 3Acrylic rubber (ACM)................................................................................................................... 4Hydrogenated Nitrile Butadiene Rubber (HNBR) ........................................................................... 4Fluoro rubber (FKM) ................................................................................................................... 4Rubber properties .......................................................................................................................... 6Specific gravity ........................................................................................................................... 6Hardness ................................................................................................................................... 6Tensile strength, elongation......................................................................................................... 7Compression set......................................................................................................................... 7Resistance to heat aging............................................................................................................. 7Rubber ingredients......................................................................................................................... 9Fillers ......................................................................................................................................... 9Plasticizers................................................................................................................................. 9Vulcanization chemicals .............................................................................................................. 9Accelerators ............................................................................................................................... 9Activators ................................................................................................................................... 9Anti degrading agents ................................................................................................................. 9Process aids............................................................................................................................... 9Pigments.................................................................................................................................... 9Rubber compounding................................................................................................................... 10Open mill.................................................................................................................................. 10Internal mixer ........................................................................................................................... 10Compound control .................................................................................................................... 11Rubber moulding ......................................................................................................................... 12Compression moulding.............................................................................................................. 12Injection moulding..................................................................................................................... 13Transfer moulding..................................................................................................................... 14Secondary finishing................................................................................................................... 17Rubber extrusion ......................................................................................................................... 18Dimensional tolerances .../Rubber cable Technology(20/36)/Properties of different Rubbers/Elastomers(28/36).............................................................................................................

19

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INTRODUCTION

Rubbers are described as materials which show “elastic” properties. Such materials are

generally long chain molecules known as “polymers” and the combination of elastic and

polymers has led to the alternative name of “elastomers”. Rubbers and elastomers will be

considered to be synonymous in this work.

Products made from rubber have a flexible and stable 3–dimensional chemical structure and

are able to withstand under force large deformations. For example the material can be

stretched repeatedly to at least twice its original length and, upon immediate release of the

stress, will return with force to approximately its original length.

Under load the product should not show creep or relaxation. Besides these properties the

modulus of rubber is from hundred to ten thousand times lower compared to other solid

materials like steel, plastics and ceramics. This combination of unique properties gives rubber

its specific applications like seals, shock absorbers, cables and tyres.

Rubber is used as a name for 3 categories:

Raw or base polymers These determine the main characteristics of the final product.

Semi-manufactured The addition to raw rubber of various chemicals, to impart desirable product properties, is termed compounding. This semi-finished material is getting its rubber properties after vulcanization. Final product After moulding the rubber compounds gets its elastic properties after a vulcanisation process.

Modern rubber materials consist of approximately 60 percent of synthetic polymers. The

other part consists of vulcanisation agents, softeners, accelerators, anti aging agents and other

chemicals. These additions are necessary to achieve the desired properties of the final

product.

Bonded flexible chains

Polymers have a backbone of hydrocarbons. The hydrogen atom is often replaced by other

atoms or molecules (like CH3, Cl or F) and thus create another type of elastomer. These

chains are chemically bonded together by sulphur, peroxides or bisphenol. An exception is

silicone. Silicone contain very flexible siloxane backbones (Si-O) and can be cured with

peroxide or platinum-catalyst curing.

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RUBBER MATERIALS

The most common elastomers are:

Ethylene Propylene Rubber (EPDM/EPM)

EPM is a copolymer of ethylene and propylene. This type can only be crosslinked with peroxides. If

during the copolymerization of ethylene and propylene, a third monomer, a diene, is added the

resulting rubber will have unsaturation and it can then be vulcanized with sulphur. These rubbers are

the so-called EPDM’s.

The main properties of EPDM are its outstanding heat, ozone and weather resistance. The resistance

to polar substances and steam are also good. It has excellent electrical insulating properties. The

EPDM copolymer can be filled with more than 200 percent of its own weight with non re-inforcing

fillers, resulting in reduction of costprice but also in physical properties. For these reasons this rubber

is widely applied in many applications.

Nitrile rubber (NBR)

NBR is a family of unsaturated copolymers of acrylonnitrile (CAN) and butadiene monomers.

Although its physical and chemical properties vary depending on the polymer’s composition of nitrile

(the more nitrile within the polymer, the higher the resistance to oils but the lower the flexibility of the

material), this form of synthetic rubber is generally resistant to oil, fuel, and other chemicals. It is used

in the automotive industry to make fuel and oil handling hoses, seals, and grommets.

NBR’s ability to withstand a range of temperatures from -25 °C to +108 °C makes it an ideal material

for automotive applications. Nitrile rubber is more resistant than natural rubber to oils and acids, but

has less strength and flexibility. Nitrile rubber is generally resistant to aliphatic hydrocarbons. Nitrile,

like natural rubber, can be attacked by ozone, aromatic hydrocarbons, ketones, esters and aldehydes.

Natural Rubber (NR)

Natural rubber has a very high elasticity, high tensile strength and a very good abrasion resistance.

The material is obtained by coagulation of latex derived from the rubber tree. The rubber is not

resistant to aging and oil. For these reasons NR is rarely used as a seal for technical applications, but

is mixed with other elastomere compounds like EPDM to improve rubber properties.

Styrene - Butadien Rubber (SBR)

SBR is a synthetic rubber copolymer consisting of styrene and butadiene. It has good abrasion

resistance and good aging stability when protected by additives, and is widely used in car tyres, where

it is blended with natural rubber.

Chloroprene rubber (CR)

Commonly known under the trade name Neoprene® of Dupont. CR is not characterised by one

outstanding property, but its balance of properties is unique among the synthetic elastomers. It has

good mechanical strength, high ozone and weather resistance, good aging resistance, low

flammability, good resistance toward chemicals and moderate oil and fuel resistance.

Silicone (VMQ/MVQ/HTV)

Silicones differ from other polymers in that their backbones consist of Si-O-Si units unlike many

other polymers that contain carbon backbones.

Silicone rubber offers good resistance to extreme temperatures, being able to operate

normally from -70 °C to +230 °C. At the extreme temperatures, the tensile strength,

elongation, tear strength and compression set can be far superior to conventional rubbers

although still low relative to other

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materials. Organic rubber has a carbon to carbon backbone which can leave them susceptible to ozone, UV, heat

and other ageing factors that silicone rubber can withstand well. This makes it one of the elastomers of choice in

many extreme environments.

Compared to organic rubbers, however, the tensile strength of standard silicone rubber is lower. For this reason,

care is needed in designing products to withstand low imposed loads. Nowadays also silicone compounds with

improved tensile strength are available.

Acrylic rubber (ACM)

Acrylic rubber, known by the chemical name alkyl acrylate copolymer (ACM), is a type of rubber that has

outstanding resistance to hot oil and oxidation. It has a continuous working temperature of 150 °C and an

intermittent limit of 180 °C. Disadvantages are its low resistance to moisture, acids, and bases. It should not be

used in temperatures below -10 °C. It is commonly used in automotive transmissions and hoses.

Hydrogenated Nitrile Butadiene Rubber (HNBR)

The properties of hydrogenated nitrile rubber depend on the acrylonitrile (ACN) content, and on the degree of

hydrogenation. They can be ‘tailored’ to particular applications, but have the general advantage over standard

nitrile rubber of having higher temperature resistance and higher strength.

HNBR’s also have good high temperature oil and chemical resistance and are resistant to amines. They are

suitable for use in methanol and methanol/hydrocarbon mixtures if the correct ACN level is selected. They have

good resistance to hot water and steam. They can have excellent mechanical properties including strength,

elongation, tear resistance, abrasion resistance and compression set. For the best properties peroxide curing is

used, unless low hysteresis is required. They are reported to be satisfactory up to temperatures around 180 °C in

oil. Fully saturated grades have excellent ozone resistance. They have poor resistance to some oxygenated

solvents and aromatic hydrocarbons.

Fluoro rubber (FKM)

Fluoroelastomers are a class of synthetic rubber which provide extraordinary levels of resistance to chemicals,

oil and heat, while providing useful service life above 204°C. The outstanding heat stability and excellent oil

resistance of these materials are due to the high ratio of fluorine to hydrogen, the strength of the carbon-fluorine

bond, and the absence of unsaturation.

The original fluoroelastomer was a copolymer of hexafluoropropylene (HFP) and vinylidene fluoride (VF2). It

was developed by the DuPont Company in 1957 in response to high performance sealing needs in the aerospace

industry. To provide even greater thermal stability and solvent resistance, tetrafluoroethylene (TFE) containing

fluoroelastomer terpolymers were introduced in 1959 and in the mid to late 1960’s lower viscosity versions of

FKMs were introduced A breakthrough in cross linking occurred with the introduction of the bisphenol cure

system in the 1970’s. This bisphenol cure system offered much improved heat and compression set resistance

with better scorch safety and faster cure speed. In the late 70’s and early 80’s fluoroelastomers with improved

low temperature flexibility were introduced by using perfluoromethylvinyl ether (PMVE) in place of HFP.

Fluoroelastomers are a family of fluoropolymer rubbers, not a single entity. Fluoroelastomers can be classified

by their fluorine content, 66%, 68% and 70% respectively. Fluoroelastomers having higher fluorine content

have increasing fluids resistance derived from increasing fluorine levels. Peroxide cured fluoroelastomers have

inherently better water, steam, and acid resistance.

Fluoroelastomers are used in a wide variety of high-performance applications. FKM provides premium, long-

term reliability even in harsh environments. A partial listing of current end use applications (industries like

aerospace and automotive) include: O-ring seals in fuels, lubricants and hydraulic systems, shaft seals, valve

stem seals, fuel injector O-rings, diaphragms, lathe cut gaskets and cut gaskets.

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Common name CHLORINATED POLYETHYLENE

Chemical name

Abbreviation CPE

Good chemical resistance to hydrocarbon fluids and elevated temperatures. Used for hose linings. Poor mechanical strength. Mechanical properties may deteriorate above 100C.

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Common name CHLOROSULPHONATED POLYETHYLENE

Chemical name

Abbreviation CSM

Trade names Hypalon®

This is a material with Neoprene polychloroprene 'plus' qualities. It is suitable for continuous use up to about 130C and intermittent use up to some 30C above this. It has excellent resistance to oxygen, ozone and most chemicals, including water, but has poor fuel resistance. It has low gas permeability. It has poor compression set resistance which limits its usefulness in dynamic sealing applications.

The following table provides a summary of the various elastomer groups and their names

according the ISO 1629 standard.

Designation Trade name Abbreviation

ISO 1629 Acrylonitrile Butadiene rubber JSR-230S NBR NIPOL Hydrogenated Acrylonitrile Butadiene rubber Therban® HNBR Zetpol® Butyl rubber Esso Butyl® IIR Chloroprene rubber Neoprene® CR ChloroSulphonatedPolyethylene Hypalon CSP Ethylene Propylene Diene Rubber Royalene EPDM Keltan® Fluorocarbon rubber Viton® FKM Fluorel® Chlorinated Polyethylene Tyrene CPE Silicone rubber Elastosil® MVQ Rhodorsil® Silopren® Fluorosilicone rubber Silastic® FMVQ Perfluoro rubber Kalrez® FFKM Chemraz® Tetrafluorethylene-Propylene Copolymeer Aflas® FEPM Polyester Urethane Adiprene® AU Polyether Urethane Pellethan® EU

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RUBBER PROPERTIES

Elastomers and rubber materials provide a variety of properties. Important specifications for elastomers and

rubber materials include mechanical, thermal, electrical, optical, processing, and physical properties.

Mechanical properties include tear strength (TS), ultimate tensile strength (UTS), tensile modulus or modulus of

elasticity, elongation, and impact toughness as measured with an Izod test and a notched sample.

Thermal properties include maximum use temperature, glass transition temperature, thermal conductivity, and

coefficient of thermal expansion (CTE).

Electrical and optical properties include electrical resistivity, dielectric strength, dielectric constant or relative

permittivity, index of refraction, and light transmission. Processing and physical properties include bulk or

apparent density, water absorption, vi scosity, process temperature, and melt flow index (MFI).

To make it possible to compare the different material characteristics several tests have been standardized. The

material datasheets provide the results of these tests. Below the most important properties are explained in more

detail.

Specific gravity

This property is fully defined by the composition of the material. Any other value will indicate another material

or composition is on hand. The specific gravity is the mass per unit volume and is measured by weighing the

sample in air and in water.

Specific gravity = weight in air / (weight in air – weight in water)

Standards: ISO 2871, ASTM D 1817

Hardness

Hardness represents the elasticity of the material. The lower the hardness the more elastic the material is. Two

scales are normally used: Shore-A and micro-IRHD. They are roughly the same. The instruments used for the

measurement are:

Durometer: a pointed conical indentor when pressed against a sample, is pushed back into the case of the tester

against a spring and this motion is translated into movement of the pointer on the dial. The harder the sample the

farther it will push back the indentor point and the higher will be the numerical reading on the scale. The unit is

Shore-A.

IRHD tester: a dead-load is applied to the indentor for a specific time and the hardness is obtained from the

depth of the indentation.

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Standards: ISO 48, ISO 1400, ISO 1818, ASTM D 2240, ASTM D 1415

Tensile strength, elongation

Tensile strength is the maximum tensile stress reached in stretching a test piece, usually a flat

dumb- bell shape, to its breaking point. By convention, the force required is expressed as

force per unit area of the original cross section of the test length.

Elongation, or strain, is the extension between bench marks produced by a tensile force

applied to the test piece and is expressed as a percentage of the original distance between the

marks. Elongation at break, or ultimate elongation, is the elongation at the moment of

rupture.


Compression set

Rubbers deform under load and rarely return completely to their original dimensions when

the load is removed. The difference between the original and final dimensions is known as

compression set. Small cylindrical disks of 13 mm diameter and a thickness of 6 mm or 29

mm diameter and a thickness of 12.5 mm are being used to perform the tests.

The disks are compressed in such a way that the compression is 25 percent of the original

height. This at a known temperature, often at 23°C (or between 70 and 250°C) with a

duration of 24 or 72 hours.

At the end of the specified time, the test pieces are removed from the test jig and allowed to

recover at 23°C for 30 minutes before the thickness is re-measured. The compression set is

the difference between the original thickness of the test piece and that after recovery,

expressed as a percentage of the initially applied compression.

As formula:

Compression set = ( Original thickness – Thickness of the piece after recovery ) / ( Original

thickness

– Height of the compression )


Resistance to heat aging

The properties of an elastomer will generally change after prolonged exposure to high

temperatures. Tests for heat aging are carried out for two reasons. Firstly, there are tests to

establish the changes in physical properties at elevated service temperatures. Secondly, there

are accelerated tests at high

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temperatures which attempt to predict the long-term life at lower temperatures. Tests are carried out in

an air oven or an oxygen pressure chamber.


Resistance to weathering

Deterioration in physical properties can occur when elastomers are exposed to the weather. This

deterioration can be observed as cracking, peeling, chalking, colour changes and other surface defects.

By far the most important cause of deterioration by weathering is the presence of ozone. Less than

one pphm of ozone in the atmosphere can severely attack non-resistant rubbers if they are in a slightly

strained condition. The result are cracks sheer on the direction of the strain. Sunlight (UV), oxygen,

moisture and temperature also affect elastomers.

Standards: 1431/1, ASTM D 1149

Resistance to low temperatures

All elastomers undergo several kinds of change when they are exposed to low temperatures. Some of

the changes occur immediately, others after prolonged exposure. All are reversible; the elastomer

regaining its original properties when it is returned to room temperature. At low temperatures the

material will become brittle and shatter on sudden bending or impact.

The temperature at which this occurs, when determined under certain prescribed testing conditions, is

called the brittle point. Another test, to measure the modulus of the material, is the material retraction

test. Generally known as the TR test.

Standards: ISO R 812, ISO 2921, ASTM D 2137, ADTM D 1053, ASTM D 1329

Abrasion resistance

A test piece is pressed against a rotating drum covered with an abrasive cloth. The loss in weight

(volume) is measured after a certain number of revolutions and gives an indication of the abrasion

resistance.


Resistance to liquids

The action of liquids on elastomers may result in the absorption of liquid by the elastomer, extraction

of soluble constituents from the elastomer or chemical reaction with the elastomer. Absorption is

usually greater than extraction and there is a net increase in volume, generally known as swelling. For

some products a decrease in volume or dimensions could be more serious than swelling and if there is

a significant chemical reaction a low swelling may hide a large deterioration in physical properties.

Consequently, although degree of swelling provides a good general indication of resistance it is also

important to measure the change in other properties. In general the following guide lines can be used:

0-5% swell; recommended, no or minor effect

5-10% swell; seal can be used in most cases, less to moderate effect.

10-20% swell; Seals only in static applications to be used, moderate to severe effect > 20% swell; not

recommended


Of course, many more properties can be tested. Depending on the application the most appropriate

tests can be selected and carried out to give the best results to predict the life time of a product.

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RUBBER INGREDIENTSRUBBER INGREDIENTSRUBBER INGREDIENTSRUBBER INGREDIENTS

A rubber compound is obtained by mixing a base polymer or crude mixture with a series of additives.

The choice of the base polymer and the additives is closely linked to the type of properties to be achieved.

The resulting product is a non vulcanized compound. The quantity of additives used varies for 20 to 130

percent as a percentage on the weight. The most common additives are:

Fillers

There are two types of fillers, reinforcing and non reinforcing fillers. Reinforcing fillers are also of two

types, black and non black. Carbon black is commonly used as black reinforcing filler. Silica is the

perfect example of nonblack reinforcing filler. Calcium carbonate, china clay are the example of a non

reinforcing filler. These are called as cost reducing filler.

Plasticizers

Besides fillers, plasticizers play the biggest quantitative role in building a rubber compound. The reasons

for the use of plasticizers are: improvement of flow of the rubber during processing, improved filler

dispersion, influence on the physical properties of the vulcanizate at low temperatures. Mineral oils and

paraffins are widely used as a plasticizer.

Vulcanization chemicals

Vulcanization is the conversion of rubber molecules into a network by formation of crosslinks.

Vulcanizing agents are necessary for the crosslink formation. These vulcanizing agents are mostly

sulphur or peroxide and sometimes other special vulcanizing agents or high energy radiation. Since

vulcanization is the process of converting the gum-elastic raw material into the rubber-elastic end

product, the ultimate properties like hardness and elasticity depend on the course of the vulcanization.

Accelerators

Accelerating agents increase the rate of the cross linking reaction and lower the sulphur content

necessary to achieve optimum vulcanizate properties.

Activators

Like zinc-oxide and stearic acid. They activate the vulcanisation process and help the accelerators to

achieve their full potential.

Anti degrading agents

These agents increase the resistance to attacks of ozone, UV light and oxygen.

Process aids

Chemicals that improve the processability.

Pigments

Organic and inorganic pigments are used to colour rubber compounds. The colour pigments are also

considered inactive fillers. Only silica’s have a reinforcing effect. Silicone can be coloured easily without

loss of properties.

RUBBER COMPOUNDING 9/36

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Compounding is the operation of bringing together all the ingredients required to mix a batch of rubber

compound. Each component has a different mix of ingredients according to the

that component. Rubber compounding is generally carried out on open mills or internal mixers.

Open mill

An open mill consists of twin counter

working to the rubber. The rolls can be heated or cooled as necessary. The rubber is placed on the rolls

and mixing is achieved by the shearing action induced at the “nip” between the rolls. Additives are added

in carefully weighed quantities during the mixing process. After the m

compound is removed from the mill in the form of sheet.

Internal mixer

Internal mixers are often equipped with two counter

rubber charge along with the additives. The

ingredients in the desired order. The shearing action generates considerable heat, so both rotors and

housing are water-cooled to maintain a temperature low enough to assure that vulcanization d

begin.


compound. Each component has a different mix of ingredients according to the properties required for


An open mill consists of twin counter-rotating rolls, one serrated, that provide additional mechanical

e rolls can be heated or cooled as necessary. The rubber is placed on the rolls


in carefully weighed quantities during the mixing process. After the mixing operation is complete, the

compound is removed from the mill in the form of sheet.

Internal mixers are often equipped with two counter-rotating rotors in a large housing that shear the

rubber charge along with the additives. The mixing can be done in three or four stages to incorporate the


cooled to maintain a temperature low enough to assure that vulcanization d

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properties required for


rotating rolls, one serrated, that provide additional mechanical

e rolls can be heated or cooled as necessary. The rubber is placed on the rolls


ixing operation is complete, the

rotating rotors in a large housing that shear the

mixing can be done in three or four stages to incorporate the


cooled to maintain a temperature low enough to assure that vulcanization does not

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Compound control

The properties of the final product are mainly determined by the properties of the compound.

Before starting the production of the final products the compound is tested to guarantee the

correct properties. This is a common applied and standard procedure in rubber compounding.

A rheometer test is carried out on every single batch of compound.

The rheometer describes precisely and quickly curing and processing characteristics of

vulcanizable rubber compounds. It works on a very simple principle. A test piece of rubber

compound is contained in a sealed test cavity under positive pressure and maintained at a

specified elevated temperature. A rotor is embedded in the test piece and is oscillated through a

small specified rotary amplitude. This action exerts a shear strain on the test piece and the

torque (force) required to oscillate the disc depends upon the stiffness of the rubber compound.

The stiffness of the specimen compound increases when cross links are formed during cure. A

plot of this torque (force) value against time gives a typical graph called rheometer curve.

The cure curve obtained with rheometer is a finger print of compound's vulcanization and

processing character.

Of course hardness and tensile strength are also checked for every batch. When all values are

within allowed parameters the compound is released for production.

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RUBBER MOULDING

Moulded rubber parts can be produced by different manufacturing methods. Major

techniques are:

Compression moulding

Compression moulding is a process in which a compound is squeezed into a preheated

mould taking a shape of the mould cavity and performing curing due to heat and

pressure applied to the material. The method uses a split mould mounted in a hydraulic

press

Compression moulding process involves the following steps:

1.A pre-weighed amount of the compound is placed into the lower half of the mould. The

compound may be in form of putty-like masses or pre-formed blanks.

2.The upper half of the mould moves downwards, pressing on the compound and forcing it to fill the mould cavity. The

mould, equipped with a heating system, provides curing (cross-linking) of the compound

3.The mould is opened and the part is removed for necessary secondary operations

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Injection moulding

Injection moulding is a process in which the compound is forced under high pressure

into a mould cavity through an opening (sprue).

The rubber material in form of strips is fed into an injection moulding machine. The

material is then conveyed forward by a feeding screw and forced into a split mould,

filling its cavity through a feeding system with sprue gate and runners.

An injection moulding machine is similar to an extruder. The main difference between

the two machines is in screw operation. In the extruder type the screw rotates

continuously providing output of continuous long product (pipe, rod, sheet).The screw

of the injection moulding machine is called a reciprocating screw since it not only

rotates but also moves forward and backward according to the steps of the moulding

cycle.

It acts as a ram in the filling step when the compound is injected into the mould and

then it retracts backward in the moulding step. The mould is equipped with a heating

system providing controlled heating and vulcanization of the material.

The compound is held in the mould until the vulcanization has completed and then the

mould opens and the part is removed from the mould.

Injection moulding is a highly productive method providing high accuracy and control

of shape of the manufactured parts. The method is profitable in mass production of

large number of identical parts. A principal scheme of an injection moulding machine is

shown here.

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Transfer moulding Transfer moulding is a process in which a pre-weighed amount of a compound is preheated in

a separate chamber (transfer pot) and then forced into a preheated mould through a sprue,

taking a shape of the mould cavity and performing curing due to heat and pressure applied to

the material. The picture below illustrates the transfer moulding process.

The method uses a split mould and a third plate equipped with a plunger mounted in a

hydraulic press. The method combines features of both compression moulding (hydraulic

pressing) and injection moulding (ram-plunger and filling the mould through a sprue).

The transfer moulding process involves the following steps:

1.A pre-weighed amount of a compound is placed into the transfer pot. The compound form

putty-like masses or pre-formed blanks. The compound is heated in the pot where the

material softens.

2.The plunger, mounted on the top plate, moves downwards, pressing on the material and forcing it to fill the mould cavity through

the sprue. The mould, equipped with a heating system, provides curing (cross-linking) of the compound.

3.The mould is opened and the parts are removed for necessary secondary operations

The scrap left on the pot bottom (cull), in the sprue and in the channels is removed. Scrap of

vulcanized rubber is not recyclable.

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The transfer moulding cycle time is shorter than compression moulding

cycle but longer than the injection moulding cycle. The method is capable

to produce more complicated shapes than compression moulding but not as

complicated as injection moulding.

Transfer moulding is suitable for moulding with ceramic or metallic inserts

which are placed in the mould cavity. When the heated compound fills the

mould it forms bonding with the insert surface.

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Secondary finishing

Depending on the requirements and production process, some secondary finishing steps

might be necessary or required:

Aftervulcanisation

Some rubber types require a process of aftervulcanisation (heating) for some hours.

HNBR and FKM rubber is aftervulcanised to give the rubber its optimal mechanical

properties after moulding.

Postcuring

Silicones parts applied in food or medical applications are mostly post cured after

moulding. Post- curing is one of the principal tools to mitigate outgassing. Post-cure is a

process that removes the volatiles from the cross-linked silicone rubber by diffusion and

evaporation and is carried out at a temperature greater than the service temperature

for the part. Post-curing also helps to improve the compression set.

Cryogene finishing

Cryogene deflashing and deburring is a step that is meant to remove excess

imperfections on moulded parts such as fleece or flash lines. The process uses liquid

nitrogen, high speed rotation and media (shot blast) in varying combinations to remove

the flash in a highly precise and expedient manner.

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RUBBER EXTRUSION

In the extrusion process of rubber, the compound including polymers, various types of additives

and fills like curing agents, antioxidants, pigments are fed into the extruder. The extruder

typically consists of a rotating screw inside a cl

of the extruder is to do three things, a) soften, b) mix, c) pressurize the rubber as it is fed

continuously to the die at the extruder exit.

The die is a sort of metal disk that has a machined opening in the desired shape of the

needs to be extruded. The rubber already softened by heating is then forced by the rotating

screw through the die opening into the shape of the profile cut in the die. A typical phenomenon

called die swell takes place as the rubber shape leaves t

section becomes larger than the die cross

material may rise up to several folds over the die.

Subsequently the processes of vulcanization or curing takes place as the l

extrusion process. This aids the rubber extruded profiles to maintain its shape and acquire

necessary physical properties. Typical examples of extruded rubber parts are profiles, hosesstrips and cords and cables.

Generally the extruded cable

(for smaller length). For that

cotton tape over sheath during extrusion

may be swelled or blisters ma

tape rolls are changed when it exhausted, at that time few wrinkles are observed

due to looseness of the tape at that particular portion, it is a mare impression of that

loose tape, nothing else. Aft

surface manually. During removal of the tape, some residual thread from the edge

of the tape remains on the surface. To remove that residual thread

rubbed by emery (sand) paper on the surfa

surface. During rubbing sometime very fine scratch mark comes on the surface, but

magnitude is negligible and for that no physical properties are changed. After

removal of tape, printing is done followed by powder

the cable sheath is extruded and vulcanised online by means of

vulcanizing (CV) process. In this case the surface of the cable shall be smooth finish. 18/36

extrusion process of rubber, the compound including polymers, various types of additives


typically consists of a rotating screw inside a closely fitted heated barrel. The


continuously to the die at the extruder exit.

The die is a sort of metal disk that has a machined opening in the desired shape of the



called die swell takes place as the rubber shape leaves the die. Because of this the part cross

section becomes larger than the die cross-section. The part cross-section depending on the

material may rise up to several folds over the die.

Subsequently the processes of vulcanization or curing takes place as the last step in the


necessary physical properties. Typical examples of extruded rubber parts are profiles, hoses

extruded cables are vulcanized in autoclave, called batch process

length). For that somebody have to apply powder and rubberised

e over sheath during extrusion , it acts as a binder tape, otherwise cable

may be swelled or blisters may form during vulcanization. During online taping, the


tape at that particular portion, it is a mare impression of that

loose tape, nothing else. After curing, the tape has to be removed


of the tape remains on the surface. To remove that residual thread the sheath is

emery (sand) paper on the surface, the thread is removed easily from the



removal of tape, printing is done followed by powder removing. For longer length

the cable sheath is extruded and vulcanised online by means of continuous

In this case the surface of the cable shall be smooth finish.

extrusion process of rubber, the compound including polymers, various types of additives


rel. The primary purpose


The die is a sort of metal disk that has a machined opening in the desired shape of the part that



he die. Because of this the part cross-

section depending on the

ast step in the


necessary physical properties. Typical examples of extruded rubber parts are profiles, hoses,

batch process

have to apply powder and rubberised

, it acts as a binder tape, otherwise cable

y form during vulcanization. During online taping, the


tape at that particular portion, it is a mare impression of that

has to be removed from the cable


the sheath is

ce, the thread is removed easily from the



For longer length,

continuous

In this case the surface of the cable shall be smooth finish.

19/36

DIMENSIONAL TOLERANCES

Rubber products are subject to changes in their dimensions after processing and

vulcanisation. This may due to a variety of factors, such as mould shrinkage or relaxation of

die swell. These changes should be determined and allowed for when designing such items as

moulds and dies used in the manufacture of a given product.

All rubbers show some shrinkage when cooled after moulding, and allowance for this is made

in the mould design. The amount of shrinkage is dependent on the rubber compound and the

mix used, but also varies from batch to batch of the same compound. Also moulds are made

in various ways depending on the type of product and accuracy demanded.

In general, the product can be no more accurate than the mould, and the greater the degree of

accuracy demanded, the more expensive become the moulds and their maintenance.

A commonly applied standard for dimensional tolerances for rubber mouldings is described

in ISO 3302-1. In these standard two sets of tolerances, F and C, are given and defined. F

(fixed) dimensions are dimensions which are not affected by deforming influences like flash

thickness or lateral displacement of different mould parts (see l1, l2 and l3).

C (closure) dimensions are dimensions which can be altered by variation in the flash

thickness or lateral displacement of different mould parts (see d1, d2, d3 and h).

The standard established four classes of tolerances for fixed and closure dimensions, varying

from M1 (high precision mouldings) to M4 (non-critical dimensional control). The tolerances

to be applied shall be chosen, by agreement between interested parties from the classes F and

C.

19/36

20/36

RUBBER CABLE TECHNOLOGY

GOVERNING SPECIFICATIONS OF RUBBER CABLES

PURPOSE: TO IDENTIFY CABLE AGAINST SPECN.

S.No. ITEM GOVERNING SPEC.

1. FLEXIBLE TRAILING CABLE IS-9968 Part-1/ PART-II / IEC-60245/ NEMA-WC-8/ MODIFIED

SHDGC/ BS-616

2. HIGH TENSION RUBBER CABLE IS-9968 Part-II / IS-14494

3. FLEXIBLE TRAILING CABLE FOR COAL

MINES

IS-14494

4. FLEXIBLE TRAILING CABLE FOR

QUARRIES & METALLIFEROUS MINES

IS-14494

5. FLEXIBLE CABLE FOR LIFT & OTHER

FLEXIBLE CONNECTIONS

IS-4289/84 PART-I/BS-6977/OTIS-03

6. ARC WELDING CABLE IS-9857/81/BS-638

7. FLEXIBLE CABLE FOR MINERS’ CAP LAMP IS-2593/84

8. RAILWAY CABLES E14/01 (PART-I)/E14/01 (PART-II)

9. SHIP WIRING CABLES DEF STAN 525, 526, 527 SERIES

10. FS CABLE BS-7846/NEK-606

11 OFF SHORE CABLES BS-6883/BS-7917

PURPOSE : TO IDENTIFY THE CABLES AGAINST SPECIFICATION.

20/36

21/36

PURPOSE :TO IDENTIFY THE COMPOUNDS AGAINST SPECIFICATIONS

GOVERNING SPECIFICATIONS OF RUBBER COMPOUNDS

RUBBER COMPOUND GOVERNING SPECIFICATIONS

1. EPR (INSULATION) : IS-6380,IE-2,IE-3,BS-6899,GP-7,DIN-VDE-0207 PT-21,3G13(E11)EI-4

2. CSP (INSULATION) : E-14/01 PT-I,CLW-ES/C-41,41A,IS-6380,IE-4,BS-6899.

3. SILICONE (INSULATION) : IS-6380,IE-5,SE-5,BS-6899,DIN-VDE-0207 PT-20,2G11(E12)

4.PCP (INSULATION) : IE-4,EM-2

5. EPR (SPECIAL GRADE) :RLY.SPECN. FOR INSULATED CATENARY,EM-2,HEPR

3

6. SEMICON COMPD. :VOLUME RESISTIVITY 1.0X10 OHM-CM MAX. AT 27±±±±2 DEG.C

7. CONDUCTING COMPD. : VOLUME RESISTIVITY 300 OHM CM MAX.AT 27±±±±2 DEG.C

8. PCP (SHEATHING) :IS-6380,SE-3,SE-4,BS-6899,RS-3,RS-4,VDE-0207 PT-21,5GM3

9. CSP (SHEATHING) : ----------------------- DO -----------------------------------------

10.NBR-PVC (SHEATHING) :------------------------ DO -----------------------------------------

11.EVA (SHEATHING ) :SHF-2,ZHFR,L F H,ZHLS,SW-4, (LFH=LIMITED FIRE HAZARD)

ACCORDING TO REQMNT. OF SPEC.DIFFERENT INHOUSE

DEVELOPED FORMULAE ARE AVAILABLE .

21/36

22/36

Raw material for

rubber compounding

Inspection

Storage

Compounding

FAILPASS

REJECTION

Conductor wire rod

INSPECTION

PASS

FAIL

Rejection

Storage

Wire drawing,

Annealing & tinning

Bunching&stranding/Melinex Taping

Insulation on CV

Line

Core Laying

Inner sheathing

Outer sheathing, RPC taping &

curing

Printing & final testing

Packing Despatch

N.C

. Handling S

ystem

Non conform

ity handling system

NO

YES

YES

YES

RUBBER CABLES FLOW CHART

SUMMERY INSTRUMRNTATION CABLE MANUFACTURING

22/36

23/36

METHOD OF MANUFACTURING OF RUBBER POWER CABLE

1)CODUCTOR MAKING = 1ST. STEP= WIRE DRAWING / 2ND.STEP = TINNIG / 3RD. STEP= BUNCHING /4TH.STEP =

STRANDING=MELINEX TAPING = READY FOR CORE MAKING

**2)COMPOUND MAKING =1ST. STEP = WEIGHING OF INGREDIENTS / 2ND. STEP =INTERNAL MIXING /3RD. STEP

=ACCELERATOR MIXING= READY FOR EXTRUSION

3)CONDUCTOR INSULATION = DONE IN EXTRUDER = SPARK TESTING (3 TO 9 KV VOLTAGE) = CORE IS READY FOR

LAYING

4)CORE LAYING = DONE IN LAYING MACHINE WITH COTTON TAPE OVER LAID UP CORE =HIGH VOLTAGE TESTING

= LAID UP CORE IS READY FOR SHEATHING

5)INNERSHEATHING (WHERE REQUIRED) = DONE IN EXTRUDER = READY FOR COTTON/ NYLON THREAD OPEN

BRAIDING = READY FOR OUTERSHEATH

6)OUTERSHEATH =DONE IN EXTRUDER = TAKEN IN TRAY / CYLINDER APPLYING POWDER ON SURFACE OF THE

SHEATH

7)COTTON TAPING = A BINDER OF COTTON TAPE IS APPLIED OVER EXTRUDED CABLE FOR STEAM

CURING/VULCANIZING BY LAPPING PROCESS = READY FOR VULCANIZING

**9)VULCANIZING = DONE IN STEAM CHAMBER AT A CERTAIN STEAM PRESSURE & SPECIFIED HOLDING TIME =

STEAM RELEASED = CABLE CYLINDER IS REMOVED FROM THE CHAMBER

10)DETAPING = THE COTTON IS REMOVED FROM THE CABLE SURFACE BY DETAPING MACHINE. = READY FOR

PRINTING

11)PRINTING = CABLE IS PRINTED BY INKJET PRINTER (NONCONTACT PRINTING) & TAKEN IN A PACKING DRUM

(IT MAY BE WOODEN OR METALLIC) = READY FOR PACKING

DIFFERENT RUBBER/ELASTOMERIC CABLES

23/36

24/36

METHOD OF MANUFACTURING OF RUBBER

INSTRUMENTATION CABLE

CONDUCTOR = GLASS MICA TAPING = INSULATION = SPARK TESTING =

TWISTING = HIGH VOLTAGE TESTING = INDIVIDUAL SHEILDING

(MELINEX/AL./MILAR WITH DRAIN WIRE/NO. PRINTEDMELINEX TAPE) =SPARK

TESTING = OVERALL SHEILDING (MELINEX / AL-MILAR WITH DRAIN WIRE /

MELINEX TAPE ) = HIGH VOLTAGE TESTING/IR VALUE CHECKING/ CR VALUE

CHECKING = INNERSHEATH = MELINEX TAPING = BRIDING ( GI WIRE ) =

MELINEX TAPING =DRAIN WIRE TO BRAID &DRAIN TO DRAIN IR VALUE

CHECKING = SHEATHING = PRINTING = TESTING = PACKING

COMPOUNDING PROCESS :-

1) BATCH PREPARATION

2) INTERNAL MIXING

3) ACCELERATOR MIXING/CURATIVES MIXING

1) BATCH PREPARATION : RAW RUBBER &DIFFERENT CHEMICALS ARE WEIGHED ACCORDING TO

FORMULATION (WHICH IS STANDARDISED INHOUSE ).

2) INTERNAL MIXING : THE WHOLE BATCH IS MIXED IN A KNEADER ( INTERNAL MIXER )

ACCORDING TO THE SEQUENCE OF MIXING EXCEPT ACCELERATOR / CURATIVES.

3) ACCELERATOR MIXING : FOR THE SAFETY OF THE COMPOUND ACCELERATOR IS MIXED IN

OPEN MILL AT LOW TEMPERATURE TO AVOID SCORCHING OF THE COMPOUND.

NOTE : AFTER MAKING THE COMPOUND, CONFORMITY IS ASSURED BY CUROMETER TESTING.

SCORCHING : IMMATURE CURING

24/36

25/36

TYPICAL EXAMPLE OF EPR COMPOUND RAW MATERIALS

EPDM RUBBER = 16.000

MODIFIER = 1.800

HEAT STABILISER = 1.000

ANTIOXIDANT(I) = 0.240

ANTIOXIDANT(II) = 0.160

INTERNAL LUBRICANT = 1.000

FILLER = 18.800

PROCESS OIL = 2.600

PROCESS AID = 0.160

COUPLING AGENT = 0.600

ACCELERATOR = 0.600

ACC. ACTIVATOR = 0.300

ITEM DOSES

IN THE MATERIAL SPEC. WE HAVE SEEN DIFFERENT TYPES OF RUBBER COMPOUNDS. NOW WE WILL SEE THE TYPICAL CHEMICALS USED FOR THOSE COMPOUNDS.

MACHINE USED IN RUBBER COMPOUNDING

1) WEIGHING MACHINE:-RANGE :5Kg.-200Kg.

2) INTERNAL MIXER :- a) KNEADER (35 Lit.- 300 Lit.)

b) BANBURY INTERMIX (35 Lit.-300 Lit.)

3) TWO ROLL MILL:- SIZE :14”X42” TO 22”X60”.

25/36

26/36

WHAT IS CURING OR VULCANIZATION PROCESS ?

#CURING/VULCANIZATION IS A PROCESS BY WHICH RUBBER COMPOUNDS GET DIMENSIONAL STABILITY. FOR WHICH A CURING SYSTEM (CURATIVES) IS TO BE INCORPORATED IN THE COMPOUNDING STAGE. WITH THIS CURING SYSTEM THE EXTRUDED COMPOUND GOT CROSSLINKED IN THE MATRIX IN PRESENCE OF HEAT. AS A RESULT OF THAT IT GETS DIMENSIONAL STABILITY.

WHY IS VULCANIZATION REQUIRED ?

#RUBBER IS A VISCO-ELASTIC MATERIAL. IT HAS PROPERTIES OF BOTH VISCOSITY AND ELASTICITY (TO SOME EXTENT). BY VULCANIZATION RUBBER IS CHANGED TO ELASTIC MATERIAL DUE TO CROSS-LINKING.

WHAT IS CV /CCV CURING ?

#CV MEANS CONTINUOUS VULCANIZATION. IT IS A PROCESS BY WHICH EXTRUSION &VULCANIZATION IS DONE AT A TIME. THE WHOLE PROCESS IS CONTINUOUS. BY WHICH WE GET A SMOOTH FINISHED CABLE. HEAT TRANSFER MEDIA IS STEAM.

WHAT IS BATCH CURING ?

#IN THIS PROCESS CABLE IS EXTRUDED OFF LINE . THEN A LAYER OF COTTON TAPE IS APPLIED OVER THE SHEATH AS A BINDER TO PROTECT THE CABLE FROM BLISTERING DURING VULCANIZATION. AT A CERTAIN STEAM PRESSURE THE CABLE WHICH IS TAKEN IN CYLINDER OR TRAY IS HOLD FOR A CERTAIN TIME (e.g. at 3kg Steam Pressure & 45mins. Holding Time) IN A VULCANIZING CHAMBER. AFTER SPECIFIED HOLDING TIME THE STEAM IS RELEASED FROM THE CHAMBER. AFTER THAT THE CABLE IS REMOVED FROM THE CHAMBER. THEN THE COTTON TAPE IS REMOVED BY DETAPING MACHINE.

ABOUT VULCANIZATION PROCESS.FOR RUBBER CABLE VULCANIZATION PART IS VERY VERY IMPORTANT

BATCH CURING CV/CCV CURING

*FOR HIGHER DIA. OF CABLE *FOR LOWER DIA OF CABLE

a) INSULATED CORE = DIA OVER 30MM a) INSULATED CORE = DIA BELOW 30 MM

b) SHEATHED CABLE =DIA OVER 40 MM b) SHEATHED CABLE =DIA BELOW 40MM

UPTO 100 MM (IN CV LINE)

SHEATHED CABLE =DIA UPTO 40 MM.

(IN CCV LINE)

c) FOR PROCESSING OF SHORTER LENGTH C) FOR PROCESSING OF LONGER LENGTH IS

d) IN BATCH PROCESS EXTRUSION IS DONE d) IN CV / CCV LINE EXTRUSION & CURING

OFF LINE FOLLOWED BY TAPING. IS DONE AT A TIME USING STEAM .

e) TAPE IMPRESSION ON CABLE SURFACE e) SMOOTH FINISH ON CABLE SURFACE

MERITS & DEMERITS OVER BATCH CURING & CV CURING.

26/36

27/36

CROSSLINKING BY ELECTRON BEAM :-

THE CHEMICAL EFFECTS OF SUBJECTING A MATERIAL TO AN

ELECTRON BEAM CAN BE TRACED TO A PHENOMENON KNOWN AS IONIZATION.

IONIZATION OCCURS IN MOLECULES SUCH AS HYDROCARBONS. HIGH ENERGY ELECTRONS GIVE UP

THEIR ENERGY TO ATOMS IN THE MOLECULE, BREAKING THE CARBON-HYDROGEN LINKS.CROSSLINKING OCCURS

THEN BY C-C BONDING.

Cross linking by Electron beam

The cross-linking of polymers through electron beam processing changes a thermoplastic

material into a thermo set. When polymers are cross linked, the molecular movement is

severely impeded, making the polymer stable against heat. This locking together of molecules

is the origin of all of the benefits of cross linking, including the improvement of the following

properties: [6]

• Thermal: resistance to temperature, aging, low temperature impact, etc.

• Mechanical: tensile strength, modulus, abrasion resistance, pressure rating, creep

resistance, etc.

• Chemical: stress crack resistance, etc.

• Other: heat shrink memory properties, positive temperature coefficient, etc.

Cross-Linking is the interconnection of adjacent long molecules with networks of bonds

induced by chemical treatment or Electron Beam treatment. Electron Beam processing of

thermoplastic material results in an array of enhancements, such as an increase in tensile

strength, and resistance to abrasions, stress cracking and solvents. Joint replacements such as

knees and hips are being manufactured from Cross-Linked Polyethylene because of the

excellent wear characteristics.

Polymers which are commonly cross linked using the electron beam irradiation process

include polyvinyl chloride (PVC), thermoplastic polyurethanes and elastomers (TPUs),

polybutylene terephthalate (PBT), polyamides / nylon (PA66, PA6, PA11, PA12),

polyvinylidene fluoride (PVDF), polymethylpentene (PMP), polyethylene’s (LLDPE, LDPE,

MDPE, HDPE, UHMWPE), and ethylene copolymers such as ethylene-vinyl acetate (EVA)

and ethylene tetrafluoroethylene (ETFE). Some of the polymers utilize additives to make the

polymer more readily irradiation crosslinkable.

Cross-linked polyethylene piping called PEX is commonly used as an alternative to copper

piping for water lines in newer home construction. PEX piping will outlast copper and has

performance characteristics that are superior to copper in many ways.

27/36

28/36

PROPERTIES OF DIFFERENT RUBBERS/ELASTOMERS 28/36

CHLOROSULPHONATED POLYETHYLENE:

Fast to light , colour fast , flame resistant , good dielectric strength ,particularly recommended for exposure to sunlight , ozone , weather and oxidizing , chemicals , however , it has a very low tensile strength.

INTERNATIONAL NAME: CSM Hardness available: 50-95 shore A RESISTANCE TO TEMPERATURES: -16 C up to +120c SHORT-TIME PEAK TEMPERATURE:- UP TO +175c TENSILE STRENGTHIN KP\SQ.CM(N\SQ.MM): 180(18) TENSILE ELONGATION IN %: 300 properties: ABRASION: Moderate RESISTANCE TO FLEX CRACKING: good TENSILE STRENGTH: good FLEXIBILITY: good STRENGTH OF STRUCTURE: excellent RESISTANCE TO LIGHT: good RESISTANCE TO OXIDIZING: excellent RESISTANCE TO OZONE: excellent RESISTANCE TO WEAR AND TEAR: good WEATHERING EFFECT: excellent RESISTANCE TO: LYES: very good PETROL: moderate BENZOLE: not suitable FOOD STUFFS: suitable SOLVENTS,ALIPHATIC: moderate SOLVENTS,AROMATIC: moderate SOLVENTS,HALOGENE: moderate OILS AND GREASES: good ACIDS: very good WATER: good

ACRYLONITRILE BUTADINE RUBBER:

Highly resistant to abrasion and tearing. , particularly resistant to ageing. Particularly recommended for crude oil .products, high temperatures, heating and lubricating oils, petrol and paraffin oil.

INTERNATIONAL NAME: NBR Hardness available: 25-95 shore A RESISTANCE TO TEMPERATURES: -10c to +140c SHORT-TIME PEAK TEMPERATURE:- UP TO +160C TENSILE STRENGTHIN KP\SQ.CM(N\SQ.MM): 250(25) TENSILE ELONGATION IN %: 500 properties: ABRASION: very good

29/36

RESISTANCE TO FLEX CRACKING: moderate TENSILE STRENGTH: good FLEXIBILITY: good STRENGTH OF STRUCTURE: good RESISTANCE TO LIGHT: bad RESISTANCE TO OXIDIZING: moderate RESISTANCE TO OZONE: moderate RESISTANCE TO WEAR AND TEAR: very good WEATHERING EFFECT: moderate RESISTANCE TO: LYES: good PETROL: excellent BENZOLE: bad FOOD STUFFS: suitable SOLVENTS,ALIPHATIC: very good SOLVENTS,AROMATIC: conditional SOLVENTS,HALOGENE: bad OILS AND GREASES: excellent ACIDS: conditional WATER: good

CHLOROPRENE RUBBER:

All purpose synthetic rubber, flame resistant, resistant to abrasion, very robust, good dielectric strength, particularly recommended for exposure to ozone and weathering.

INTERNATIONAL NAME: CR Hardness available: 30-90 shore A RESISTANCE TO TEMPERATURES: -40c to +120c SHORT-TIME PEAK TEMPERATURE:- UP TO +150C TENSILE STRENGTHIN KP\SQ.CM(N\SQ.MM): 50(25) TENSILE ELONGATION IN %: 450 properties: ABRASION: good RESISTANCE TO FLEX CRACKING: very good TENSILE STRENGTH: good FLEXIBILITY: good STRENGTH OF STRUCTURE: good RESISTANCE TO LIGHT: very good RESISTANCE TO OXIDIZING: good RESISTANCE TO OZONE: very good RESISTANCE TO WEAR AND TEAR: very good WEATHERING EFFECT: very good RESISTANCE TO: LYES: very good PETROL: moderate BENZOLE: not suitable FOOD STUFFS: suitable SOLVENTS,ALIPHATIC: moderate SOLVENTS,AROMATIC: moderate SOLVENTS,HALOGENE: bad OILS AND GREASES: good ACIDS: good WATER: very good 29/36

30/36

30/36

STYRENE BUTADINE RUBBER:

Similar to natural rubber, resistant to abrasion, rubbing in good resistance to high temperatures and cracking, resistance to extreme low temperatures, not resistant to petrol, benzene, greases and oils...

INTERNATIONAL NAME: SBR Hardness available: 35-95 shore A RESISTANCE TO TEMPERATURES: -49c to +110c SHORT-TIME PEAK TEMPERATURE:- UP TO +150C TENSILE STRENGTHIN KP\SQ.CM(N\SQ.MM): 250(25) TENSILE ELONGATION IN %: 450 properties: ABRASION: very good RESISTANCE TO FLEX CRACKING: good TENSILE STRENGTH: good FLEXIBILITY: good STRENGTH OF STRUCTURE: good RESISTANCE TO LIGHT: moderate RESISTANCE TO OXIDIZING: moderate RESISTANCE TO OZONE: moderate RESISTANCE TO WEAR AND TEAR: very good WEATHERING EFFECT: good RESISTANCE TO: LYES: good PETROL: not suitable BENZOLE: not suitable FOOD STUFFS: suitable SOLVENTS,ALIPHATIC: not suitable SOLVENTS,AROMATIC: not suitable SOLVENTS,HALOGENE: not suitable OILS AND GREASES: not suitable ACIDS: conditional WATER: very good

EPDM (ETHYLENE PROPYLENE DIENE-RUBBER)

Versatile in use , very good flexibility , resistant to abrasion , resistant to wear and tear ,ozone and weather , low temperatures , can be used to protect against, washing , spraying agents , excellent for profile cords not usable in conjunction with petrol , solvents and mineral oils.

INTERNATIONAL NAME: EPDM/EPM Hardness available: 30-90 shore A RESISTANCE TO TEMPERATURES: -55c up to +150c SHORT-TIME PEAK TEMPERATURE:- -UP TO +180c TENSILE STRENGTHIN KP\SQ.CM(N\SQ.MM): 200(20) TENSILE ELONGATION IN %: 450 properties: ABRASION: good

31/36

RESISTANCE TO FLEX CRACKING: very good TENSILE STRENGTH: good FLEXIBILITY: good STRENGTH OF STRUCTURE: moderate RESISTANCE TO LIGHT: excellent RESISTANCE TO OXIDIZING: excellent RESISTANCE TO OZONE: excellent RESISTANCE TO WEAR AND TEAR: good WEATHERING EFFECT: excellent RESISTANCE TO: LYES: excellent PETROL: not suitable BENZOLE: not suitable FOOD STUFFS: suitable SOLVENTS,ALIPHATIC: bad SOLVENTS,AROMATIC: not suitable SOLVENTS,HALOGENE: not suitable OILS AND GREASES: bad ACIDS: very good WATER: very good

SILICONE RUBBER: 31/36

Resistant to high temperature ,odourless and tasteless , nontoxic , can be sterilized in accordance with foodstuffs regulations ,, resistant to sea water and corrosive salt solutions , not to be used in conjunction with steam water concentrated acids and lies , swells. Strongly under the effect of aromatic solvents.

INTERNATIONAL NAME: MVQ/SI Hardness available: 40-80 shore A RESISTANCE TO TEMPERATURES: -70c up to +180c SHORT-TIME PEAK TEMPERATURE:- UP TO +225c TENSILE STRENGTHIN KP\SQ.CM(N\SQ.MM): 80(8) TENSILE ELONGATION IN %: 250 properties: ABRASION: Moderate RESISTANCE TO FLEX CRACKING: bad TENSILE STRENGTH: bad FLEXIBILITY: good STRENGTH OF STRUCTURE: moderate RESISTANCE TO LIGHT: excellent RESISTANCE TO OXIDIZING: very good RESISTANCE TO OZONE: excellent RESISTANCE TO WEAR AND TEAR: bad WEATHERING EFFECT: excellent RESISTANCE TO: LYES: not suitable PETROL: not suitable BENZOLE: not suitable FOOD STUFFS: excellently suitable SOLVENTS,ALIPHATIC: not suitable SOLVENTS,AROMATIC: not suitable SOLVENTS,HALOGENE: not suitable OILS AND GREASES: good ACIDS: not suitable WATER: good

32/36

32/36

NATURAL RUBBER:

Characterized by flexibility strength and low temperature resistance as well as excellent physical properties ideal for bonded rubber/metal elements. Not suitable for petreol, grease, oils and ozone.

INTERNATIONAL NAME: NR Hardness available: 25-95 shore A RESISTANCE TO TEMPERATURES: -40c to +80c SHORT-TIME PEAK TEMPERATURE:- +100C TENSILE STRENGTHIN KP\SQ.CM(N\SQ.MM): 250(25) TENSILE ELONGATION IN %: 800 properties: ABRASION: good RESISTANCE TO FLEX CRACKING: good TENSILE STRENGTH: excellent FLEXIBILITY: excellent STRENGTH OF STRUCTURE: excellent RESISTANCE TO LIGHT: bad RESISTANCE TO OXIDIZING: moderate RESISTANCE TO OZONE: moderate RESISTANCE TO WEAR AND TEAR: very good WEATHERING EFFECT: good RESISTANCE TO: LYES: good PETROL: not suitable BENZOLE: not suitable FOOD STUFFS: suitable SOLVENTS,ALIPHATIC: not suitable SOLVENTS,AROMATIC: not suitable SOLVENTS,HALOGENE: not suitable OILS AND GREASES: not suitable ACIDS: conditional WATER: good

ACRYLIC RUBBER:

Good resistance to high temperature and mineraloils, high resistance to oxygen low -temperature properties.

INTERNATIONAL NAME: ACM Hardness available: 50-80 shore A RESISTANCE TO TEMPERATURES: - 35c to +175c SHORT-TIME PEAK TEMPERATURE:- +200C TENSILE STRENGTHIN KP\SQ.CM(N\SQ.MM): 160(16) TENSILE ELONGATION IN %: up to 350 properties:

33/36

ABRASION: Moderate RESISTANCE TO FLEX CRACKING: Moderate TENSILE STRENGTH: good FLEXIBILITY: OF low STRENGTH OF STRUCTURE: - RESISTANCE TO LIGHT: good RESISTANCE TO OXIDIZING: very good RESISTANCE TO OZONE: very good RESISTANCE TO WEAR AND TEAR: good WEATHERING EFFECT: very good RESISTANCE TO: LYES: not suitable PETROL: not suitable BENZOLE: not suitable FOOD STUFFS: not suitable SOLVENTS,ALIPHATIC: not suitable SOLVENTS,AROMATIC: bad SOLVENTS,HALOGENE: bad OILS AND GREASES: very good ACIDS: not suitable WATER:

FLUORINATED RUBBER (VITON):

Hexafluoroprppylene . Vinylidene fluoride. Copolymer.Resistant to extreme temperature even over 200c .Very good mechanical properties and high resistance to tearing even at high temperatures .Excellent for exposure to sunlight, ozone and weather .Not recommended for use in conjunction with esters and ketones.

INTERNATIONAL NAME: FPM Hardness available: 60-90 shore A RESISTANCE TO TEMPERATURES: -30c up to +225c SHORT-TIME PEAK TEMPERATURE:- UP TO +350c TENSILE STRENGTHIN KP\SQ.CM(N\SQ.MM): 200(20) TENSILE ELONGATION IN %: 400 properties: ABRASION: Moderate RESISTANCE TO FLEX CRACKING: good TENSILE STRENGTH: good FLEXIBILITY: moderate STRENGTH OF STRUCTURE: almost good RESISTANCE TO LIGHT: excellent RESISTANCE TO OXIDIZING: excellent RESISTANCE TO OZONE: excellent RESISTANCE TO WEAR AND TEAR: almost good WEATHERING EFFECT: excellent RESISTANCE TO: LYES: very good PETROL: excellent BENZOLE: good FOOD STUFFS: not suitable SOLVENTS,ALIPHATIC: very good SOLVENTS,AROMATIC: good SOLVENTS,HALOGENE: good OILS AND GREASES: good ACIDS: very good WATER:

33/36

34/36

POLYBORON RUBBER 34/36

High mechanical strength, good resistance to ozone medium resistance to oil flexibility\damping property can be varied as required. Excellent resistance to water\, slight permanent set.

INTERNATIONAL NAME: PNR Hardness available: 10-80 shore A RESISTANCE TO TEMPERATURES: -30c to +80c SHORT-TIME PEAK TEMPERATURE:- +100C TENSILE STRENGTHIN KP\SQ.CM(N\SQ.MM): 170(17) TENSILE ELONGATION IN %: 300 TO 700 properties: ABRASION: good RESISTANCE TO FLEX CRACKING: moderate TENSILE STRENGTH: good FLEXIBILITY: as required STRENGTH OF STRUCTURE: moderate RESISTANCE TO LIGHT: good RESISTANCE TO OXIDIZING: good RESISTANCE TO OZONE: good RESISTANCE TO WEAR AND TEAR: good WEATHERING EFFECT: good RESISTANCE TO: LYES: moderate PETROL: not suitable BENZOLE: not suitable FOOD STUFFS: not suitable SOLVENTS,ALIPHATIC: not suitable SOLVENTS,AROMATIC: not suitable SOLVENTS,HALOGENE: not suitable OILS AND GREASES: conditional ACIDS: moderate WATER: excellent

EPICHLOROHYDRIN RUBBER:

Low gas permeability, very good low temperature properties, good resistance to mineral oils ozone and high temperature

INTERNATIONAL NAME: eco Hardness available: 50-90 shore A RESISTANCE TO TEMPERATURES: -40c to +130c SHORT-TIME PEAK TEMPERATURE:- +150C TENSILE STRENGTHIN KP\SQ.CM(N\SQ.MM): 170(17)

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TENSILE ELONGATION IN %: 150 TO 500 properties: ABRASION: moderate RESISTANCE TO FLEX CRACKING: good TENSILE STRENGTH: good FLEXIBILITY: moderate STRENGTH OF STRUCTURE: good RESISTANCE TO LIGHT: good RESISTANCE TO OXIDIZING: good RESISTANCE TO OZONE: very good RESISTANCE TO WEAR AND TEAR: - WEATHERING EFFECT: good RESISTANCE TO: LYES: bad PETROL: good BENZOLE: good FOOD STUFFS: not suitable SOLVENTS,ALIPHATIC: good SOLVENTS,AROMATIC: good SOLVENTS,HALOGENE: not suitable OILS AND GREASES: very good ACIDS: moderate WATER: m

BUTYL RUBBER: 35/36

Very slightly permeable to air, steam and other gases ,good resistance to heat, oxygen, ozone and many chemicals and solvents, good electrical properties(isolating),good resistance to abrasion and tear propagation.

INTERNATIONAL NAME: IIR Hardness available: 45-85 shore A RESISTANCE TO TEMPERATURES: -40c to +130c SHORT-TIME PEAK TEMPERATURE:- +150 TENSILE STRENGTHIN KP\SQ.CM(N\SQ.MM): 170(17) TENSILE ELONGATION IN %: 400 to 800 properties: ABRASION: good RESISTANCE TO FLEX CRACKING: moderate TENSILE STRENGTH: good FLEXIBILITY: slight STRENGTH OF STRUCTURE: good RESISTANCE TO LIGHT: very good RESISTANCE TO OXIDIZING: very good RESISTANCE TO OZONE: very good RESISTANCE TO WEAR AND TEAR: - WEATHERING EFFECT: very good RESISTANCE TO: LYES: very good PETROL: not suitable BENZOLE: not suitable FOOD STUFFS: suitable SOLVENTS,ALIPHATIC: not suitable SOLVENTS,AROMATIC: not suitable SOLVENTS,HALOGENE: not suitable OILS AND GREASES: not suitable ACIDS: very good WATER:

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HYDROGENATED NBR:

High resistance to heat, ozone and oil, good mechanical properties also at high temperatures, excellent resistance to wear and tear...

INTERNATIONAL NAME: HNBR Hardness available: 40-90 shore A RESISTANCE TO TEMPERATURES: -25c to +175c SHORT-TIME PEAK TEMPERATURE:- +200c TENSILE STRENGTHIN KP\SQ.CM(N\SQ.MM): 300(30) TENSILE ELONGATION IN %: 150 to 600 properties: ABRASION: very good RESISTANCE TO FLEX CRACKING: very good TENSILE STRENGTH: very good FLEXIBILITY: good STRENGTH OF STRUCTURE: good RESISTANCE TO LIGHT: good RESISTANCE TO OXIDIZING: good RESISTANCE TO OZONE: good RESISTANCE TO WEAR AND TEAR: good WEATHERING EFFECT: good RESISTANCE TO: LYES: good PETROL: good BENZOLE: moderate FOOD STUFFS: not suitable SOLVENTS,ALIPHATIC: very good SOLVENTS,AROMATIC: conditional SOLVENTS,HALOGENE: conditional OILS AND GREASES: very good ACIDS: moderate(conditional) WATER:

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Rubber technology A

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