Rubber, epichlorohydrin

Hercules Chemical invented and filed the original patent for epichlorohydrin rubber in 1957. They later licensed this technology and patents to BF Goodrich Chemical Co., which later sold all their interest in epichlorohydrin rubber to Zeon Chemical 

Epichlorohydrin is a common choice in the automotive industry when a good combination of heat, fuel, and oil resistance is needed. On the other hand, its total production volume is relatively small compared to other specialty elastomers. 

ECO (official ASTM abbreviation for epichlorohydrin copolymer with ethylene 

Epichlorohydrin is necessary for both the homopolymer as well as the copolymer. It is produced from the chlorination of propylene as shown in Eigure 4.35. 

There is no official classification system for epichlorohydrin. However, Mooney viscosity (ASTM D1646) is commonly used to crudely define average molecular weight. The molar content of ethylene oxide present in ECO is important. Greater ethylene oxide present will improve the elastomer s low-temperature properties. Originally it was found that a 50 50 molar ratio of epichlorohydrin and ethylene oxide gave one of the best compromises in properties, with good low-temperature properties and only a small loss in oil resistance. 

The epichlorhydrin polymer group includes the homopolymer (CO), the copolymer with ethylene oxide (ECO), and terpolymers (GECO). 

These rubbers have excellent resistance to sun, weathering, and ozone. 

Epichlorhydrin rubbers are resistant to hydrocarbon fuels, to swelling in oils, and resistant to acids, bases, water, and aromatic hydrocarbons. However, they are susceptible to devulcanization in the presence of oxidized fuels such as sour gasoline. 

Epichlorhydrin rubber applications include seals and tubes in air-conditioning and fuel systems. 

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The rubbers may be vulcanised by conventional accelerated sulphur systems and also by peroxides. The vulcanisates are widely used in petrol hose and seal applications. Two limiting factors of the materials as rubbers are the tendency to harden in the presence of sulphur-bearing oils, particularly at elevated temperatures (presumably due to a form of vulcanisation), and the rather limited heat resistance. The latter may be improved somewhat by Judicious compounding to give vulcanisates that may be used up to 150°C. When for the above reasons nitrile rubbers are unsatisfactory it may be necessary to consider acrylic rubbers (Chapter 15), epichlorohydrin rubbers (Chapter 19) and in more extreme conditions fluororubbers (Chapter 13). 

Epichlorohydrin rubber Thermoplastic polyurethanes Nitrile rubber... 

However, butyl rubber and epichlorohydrin rubber cannot be peroxide-crosslinked. 

The development and optimisation is described of a new curing system to replace lead-based compounds used in epichlorohydrin elastomers currently used in automotive applications. The system is based on 2,4,6-trimercapto-1,3,5-triazine and dialkyldithiophosphate, which is shown to produce a scorch-safe curing system and which confers excellent physical and ageing properties on epichlorohydrin rubbers. Trials are conducted in formulations for multilayer fuel hoses. 9 refs. 

Allyl Glycidyl Ether. This ether is used mainly as a raw material for silane coupling agents and epichlorohydrin rubber. 

Commercially the most important use is production of glycerine. Large volumes are consumed in nonglycenne areas, which largely consist of ihe various epoxy resins. It has use as a solvent and in the production of epichlorohydrin rubber. 

The blends of XNBR and chlorobutyl rubber (CIIR) and XNBR-epichlorohydrin rubber (ECO) act as adhesive for aluminium-aluminium bonding [171,172], In order to study the adhesion between CIIR-XNBR blend on aluminium foil, Bhattacharya and co-workers... 

Meissner, B., Schatz, M. and Brajko, V., Synthetic Rubbers Epichlorohydrin Rubber , in Studies in Polymer Science. Vol. 1. Elastomers and Rubber Compounding Materials, Elsevier, Amsterdam, 1989, pp. 274-278. 

Some materials that have achieved importance include EPDM/PP, NBR/PA, PU/PA, SEBS/PA, EPDM/PBT, and Epichlorohydrin rubber/PA. Usually, these materials are made more process-able through plasticizing oils. Holden [1996]... 

Rubbery behavior—large, reversible extensibility—implies an absence of crystallinity, and this is usually the case for undeformed elastomers. However, small extents of crystallization may be present at ambient temperature in some elastomers, including EPDM with high ethylene content, epichlorohydrin rubber, and polypropylene oxide. The crystallites in these materials can act as reinforcing agents. Many thermoplastic elastomers have crystalline domains that function as reversible crosslinks (Rzymski and Radusch, 2005 Bhowmick and Stephens, 2001). 

Hazardous Decomp. Prods. Heated to decomp., emits very toxic fumes of NOx and SOx Uses Curing agent for epichlorohydrin rubber Manuf./Distrib. Aldrich http //www.sigma-aldrich.com... 

Cellulose acetate Cellulose acetate-butyrate Cellulose acetate-propionate Cresol-formaldehyde resin Epichlorohydrin-ethylene oxide rubber Epichlorohydrin rubber (see also CO)... 

Carboxynitroso, rubber (tetrafluoroethylene-tri-fluoronitrosomethane-unsat. monomer terpolymer) Poly[(chloromethyl)oxirane] epichlorohydrin rubber (see also CHR)... 

Examples of vulcanizable elastomers include natural rubber (NR), styrene butadiene rubber (SBR), butadiene rubber (BR), ethylene-propylene-diene monomer-rubber (EPDM), butyl rubber (HR), polychloroprene or neoprene (CR), epichlorohydrin rubber (ECO), polyacrylate rubber (ACM), millable polyurethane rubber, silicone rubber, and flu-oroelastomers. Examples of thermoplastic elastomers include thermoplastic polyurethane elastomers, styrenic thermoplastic elastomers, polyolefin-based thermoplastic elastomers, thermoplastic polyether-ester (copolyester) elastomers, and thermoplastic elastomers based on polyamides. 

Ethylene oxide (oxirane) and chloromethyl oxirane (epichlorohydrin) copolymer Epichlorohydrin rubber, Hydrin ECO... 

CR is superior to NR or SBR as a barrier against gas permeation, but it does not exhibit as low permeability as do butyl rubbers, epichlorohydrin rubbers, or nitrile rubbers. 

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