Acrylic Elastomer

Acrylic Elastomer is a general term for synthetic rubber whose main component is acrylic acid alkylester (ethyl or butylester). Also called polyacrylate, acrylic elastomer has characteristics of heat resistance and oil resistance. It is divided into old type and new type: Old types include ACM (copolymer of acrylic acid ester and 2-chloroethyl vinyl ether) containing chlorine and ANM (copolymer of acrylic acid ester and acrylonitrile) without chloride. Other than the slightly better water resistance of ANM, there are no physical differences; even processability is poor for both types. Since prices are also high, demand is not so high vis-à-vis the characteristics. On the other hand, the new type of acrylic rubber does not contain any chlorine despite its unclear chemical composition. Processability has been improved, and most of tackiness to rolls as well as staining problems related to molds have been solved. Major characteristics of acrylic rubber include heat resistance and oil resistance; it can endure a temperature of 170 ~ 180℃ under dry heat or in oil. Since it does not have a double bond, acrylic rubber also boasts of good weatherability and ozone resistance. Its cold resistance is not that good, however.

The saturation point is -15℃ for the old type and -28 ~ -30℃ for the new type. In terms of vulcanization, the standard method for the old type is amine vulcanization. To minimize permanent deformation, the old type requires curing for 24 hours under a temperature of 150℃. On the other hand, for the new type, the press curing time and follow-up vulcanization time are significantly reduced by combining metal soap and sulfur. It has no special characteristics. The rebound resilience and abrasion resistance of the new type are poor, and even its electrical characteristics are considerably poor compared with acrylonitrile-butadiene rubber and butyl rubber. The materials are used mainly for oil seals and packagings related to automobiles.