RUBBER COMPOUNDING

1. BHUKYA KIRANKUMAR B120485CH

2. JOBIN VARGHESE JACOB B110733CH

3. SANDEEP SUKUMARAN B110819CH

Rubber :Rubbers are described as materials which show

“elastic” properties.

Products made from rubber have a flexible and stable 3–dimensional chemical structure and are able to withstand under force large deformations.

APPLICATION OF RUBBER: Today, rubber is as widely used as wood and this

is largely due to its beneficial proprieties like strength, long lasting, water resistance and heat resistance all these benefits makes this material perfect for tire production.

playground equipment, shoes, mats, flooring, healthcare supplies, household supplies, balls, toys and thousands of other rubber products

RAW MATERIALS :A typical rubber formation based on parts per hundred is:Polymer       100 phrFiller              30 – 60 phrAntioxidant     1 – 3 phrAntiozonants   1 – 3 phrOil             5 – 30 phrCure            5 - 10 phr

OPEN OR INTERNAL MIXERS :Rubber compounding is generally carried out

on open mills or internal mixers.

Polymers :

Most important ingredient in rubber compound is polymer.

Act as the basis for physical , chemical and molding properties.

Polymers are distinguished by chemical perfomence and viscosity rating.

Filler :

Gives the rubber compounds physical strength and black colour .

They have various particle sizes and surface activity.

Change in particle size can increase physical properties .

Carbon black is most common filler.Mineral fillers helps to make the compound

white to add the desired colour.

Antioxidant : Protect the compound from high temperature. They absorb free radicals which cause the polymer

bonds to break and reduce service life of the compound.

Antiozonants : used to prevent rubber from ozone effect Surface of new tyres will have wax feel or shows slight

haze Most common antioxidant is wax ,which is used on the

surface after molding.

Oils( processing aids): Oils are used to incorporate all dry ingredients in rubber

coumpounding. They reduce viscosity of overall compound to help with

molding. More oil helps to reduce hardness of rubber.

Cures :Vulcanization – bonds of carbon –sulphur –carbon

formed.Peroxide vulcanizing agent creates direct bonds to

the carbon chains forming carbon carbon bonds.

Rubber Compounding (Def) :

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

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

A rubber compound could be a combination of 3 to 15 different ingredients of thousands of different compositions and vendors.

Types of rubbers :1.CPE ( chlorinated polyethylene ) PROPERTIES : Offers excellent flexibility Resistance to ignition Resistance to low temperatures,abrasion and weathering Has high filler acceptance , tensile strength Low cost

USES : Wire and cable jackets

Coated fabrics

EDPM ( ethylene propylene diene monomer) :PROPERTIES : Have outstanding resistance to heat ,ozone and

weather . Resistance to water glycol steam and polar chemicals. Excellent electrical insulating properties.

USES :

1. For roofing membranes geomembranes .

2. Used in radiators and for electrical insulation.

Natural rubber :PROPERTIES : Has good resilience and surface friction properties Has low hysteresis and high fatigue resistors Has poor resistance to oil sunlight and ozone

USES :1. Used in high performance tires for race cars,trucks and

air craft

2. For tank lining and vibration dampening

NBR ( nitrile butadiene rubber) :PROPERTIES : Good elongation Adequate resilience Tensile strength

USES :1. It is used to create oil and gas exploration and recovery

parts

2. Used for foot wear and molded goods

3. Carboxilated nitrile rubber has high tear and abrasion resistance

SBR ( styrene butadiene rubber):PROPERTIES : Good abrasion and ageing resistance when protected by

additives Good heat and oil resistance

USES :1. Foot wear

2. Adhesives

3. Floor tyles

4. Rubber goods

Classification of materials :ElastomersVulcanizing or cross linking agentsAcceleratorsActivator/retardersProcess aidsSoftners and plasticizersReinforces / fillers