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Elastomers are divided into groups as per ISO 1629 or ASTM.We can offer you a large number of materials within each group.
Group	Chemical Term	Trade Name	ISO 1629	ASTM? Abbreviations
M	Polyacrylate Rubber	Hytemp, Noxtite, Nipol AR	ACM	ACM
	Ethylene Propylene Diene Rubber	Keltan, Vistalon, Buna EP	EPDM	EPDM, EP, EPT, EPR
	Fluorocarbon Rubber	Fluorel, Tecnoflon, Viton	FKM	FKM
O	Epichlorohydrin	Gechron, Hydrin	ECO	ECO/CO
R	Chloroprene Rubber	Baypren, Neoprene	CR	CR
	Butyl Rubber	Esso Butyl	IIR	IIR
	Nitrile Rubber (Acrylonitrile-Butadiene Rubber)	Krynac, Buna-N, Nipol N, Breon	NBR	NBR
	Natural Rubber	?	NR	NR
	Styrene-Butadiene Rubber	Buna S, Europrene, Polysar S	SBR	SBR
	Hydrogenated Acrylonitrile-Butadiene Rubber	Therban, Zetpol	HNBR	HNBR
O	Fluorosilicone Rubber	Silastic	FVMQ	FVMQ
O	Silicone Rubber	Elastoseal, Silastic, Silopren	VMQ	VMQ, PMQ, PVMQ
U	Polyester Urethane, Polyether Urethane	Zurcon, Adiprene, Vulcollan, Desmopan	AU, EU	AU, EU

2、Some introduction to rubber

Chloroprene Rubber (CR)? ???? ? ? ? ?-40°~100℃? ? ? ?Special Compound? ?-55°~125°C

? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? -40°~212°F? ? ? ?Special Compound? ?-67°~257°F??

General Information
ASTM D2000
SAE J 200 Codes? ? ? ? ? ?BC, BE
Relative Cost? ? ? ? ? ? ? ? ?Low
Primary Uses
Refrigeration industry applications
General purpose seals, hose and wire
Performs Well in...
Refrigerants - Freon?
Ammonia
Water and water solvents at low temperatures
Silicone grease and oils
Ozone, aging & weathering

Description
CR, one of the first synthetic rubbers for seals, is often called Neoprene. It’s a chloroprene (chlorobutadiene) homopolymer, unique for moderate petroleum/weather (ozone, UV, O?) resistance. As a general elastomer, it has low compression set, good resilience/abrasion, and flex-crack resistance.
Application Advantages
Moderate petroleum/weather, good ozone/UV/O?, excellent Freon?/ammonia resistance
Limitations
In O-rings, Neoprene is mostly replaced by Nitrile: Nitrile is economically competitive, performs better in most situations, and has moderate water resistance.

Epichlorohydrin (CO, ECO, GECO)?? ? ? ? ? ?°C: -40°~125°C; Special Compound: -40°~135°C
? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? °F: -40°~257°F; Special Compound: -40°~257°F

General Information
ASTM D2000
SAE J 200 Codes: CH
Relative Cost: Medium
Primary Uses
Automotive: Fuel pump diaphragms, hoses, motor mounts, boots, seals
General industrial use
Medical: Oxygen mask hoses
Performs Well in...
Mineral oil and grease
LPG, fuels
Silicone oil and grease
Ozone and weathering

Description
Epichlorohydrin is available in three types: the homopolymer (CO), the copolymer (ECO), and the terpolymer (GECO).
Application Advantages
Resistant to ozone, weathering and oils
Good heat resistance
Very low permeability to gas
Limitations
Compounds from this polymer can exhibit a corrosive nature and can be difficult to process in manufacturing.
Compression set is only "fair" at elevated temperatures (120° to 135°C, 250° to 275°F).

3、How to select rubber materials.

When selecting rubber materials for sealing, there are a number of important selection criteria to be considered:
01

The service conditions to be considered include

1)Fluid to be sealed 2)Temperature range 3)Pressure range 4)Motion - either static or dynamic.
02

The design requirements to be considered include

1)Component geometry/description, like O-ring,gasket,diaphragm,etc. 2)The effect of chemical/fluid media on the seal. 3)Desired service life.Find out the reason and which material was used for a failed seal. 4)Lubrication level and assembly methods,including lubricants,installed stretch,etc. 5)Critical dimensions and tolerances,including groove dimensions and machining tolerances.
03

The inspection requirements to be considered include

1)Defining inspection criteria. 2)Determining the need for lot sampling. 3)Setting acceptable quality levels (AQLs). 4)Indicating the critical sealing surface.

04

The selection of material specification

1)Define material specifications,such as the American ASTM,German DIN,Japanese JIS,Chinese GB. 2)Discuss with your supplier to specify sealing materials. 3)Choose suppliers with stable quality and delivery.
05

Select suitable rather than high - cost and impractical rubber materials.

Natural or synthetic rubber has key properties:springs back when pressed,resists bending/squeezing,and blocks gas/liquid well.Each type has unique traits;experts mix it specifically for engineering needs.Curing turns soft,moldable rubber into hard,shaped,form-holding rubber.Crosslinking gives it strength and stretch for good sealing.