Ethylene Propylene Rubber ( EPR, EPDM )

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13 Nov 2022

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EPDM

Ethylene Propylene Rubber ( EPR, EPDM )

EPDM is a copolymer of ethylene and propylene, and further a terpolymer of ethylene and propylene with a small amount of a third monomer ( usually a diolefin ) to permit vulcanization with sulfur.Generally Ethylene Propylene Rubber possesses excellent resistance to ozone, sunlight and weathering, and has very good flexibility at low temperature, good chemical resistance ( many dilute acids and alkalis, polar solvents ), and good electrical insulation property.

Cure system Bisphenol cured vs. Peroxide – Cured

►Standard EPDMs are usually sulfur – cured. Sulfur-cured compounds offer better flexible properties but are more Prone to hardening and poorer compression set with high temperature.

►Peroxide – cured EPDMs have better heat resistance and lower compression set. It complies with long time usage especially for hose system of construction industry, but at the same time is more expensive and more difficult for production than the Sulfur – cured.

Other Common Variations:

►EPDMs are often internally lubricated to improve ease of installation or reduce friction for dynamic applications.

►EPDMs can be formulated with only “white list” ingredients as specified in 21.CFR 177.2600 for use in applications where the elastomer will be in contact with foodor beverages.

►EPDMs can be submitted for approval by the National Sanitation Foundation (NSF) for use in drinking water applications.

►EPDMs are usually used in automotive air conditioning system where R134a refrigerant gas and POE or PAG lubricant and new refrigerant for environment protection R744 is used. In R744 air conditioning system, it requires excellent resistance to explosivedecompression in hydrogen dioxide at high pressure and high temperature.

►EPDMs are usually used in phosphate ester type Hydraulic fluids.

Performs Well In…

►Alcohols

►Automotive brake fluid

►Ketones

►Dilute acids and alkalis

►Silicone oils & greases

►Steam to 400°F

►Water

►Phosphate ester based

®hydraulic fluids – Skydrol

►Ozone, aging & weathering

Doesn’t Perform Well In…

►Aliphatic & aromatic hydrocarbons

►Di-ester based lubricants

►Halogenated solvents

►Petroleum based oils & greases

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admin_ilkhani

14 Nov 2022

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Carboxylated Nitrile ( XNBR )

XNBR Carboxylated Nitrile ( XNBR ) Cabboxylated Nitrile is similar to Nitrile rubber, but the polymer backbone has been chemically modified with Carboxylic Acid containing group. This result is XNBR with more excellent abrasion and tear resistance than traditional NBR. For this reason, XNBR based parts are usually applied in dynamic assembly such as seals and rod wipers. Cure system - Sulfur - Cured Standard XNBR compounds are sulfur-cured Performs Well In… ►Aliphatic hydrocarbon ►Vegetable and mineral oils and greases ►Diesel ►Water Dilute acids, alkali and salt solutions Doesn't Perform Well ...

admin_ilkhani

14 Nov 2022

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Silicone Rubber ( MQ, VMQ, PVMQ )

VMQ Silicone Rubber ( MQ, VMQ, PVMQ ) Physically, silicones are based on silicon, an element derived from quartz. To create this class of synthetic elastomers, pendant organic groups such as methyl, phenyl and vinyl are attached to silicon atoms. The different addition of side chains can achieve significant variations in properties. Silicones have excellent heat, ozone and corona resistance, very well dielectric stability, and resistance to many oils, chemicals, and solvents. And for all elastomers, silicones possess the best flexible property ...