Special adhesives for rubber bonding

Special adhesives for bonding of unvulcanized and vulcanized elastomers are discussed. Major emphasis is placed on adhesives and conditions for bonding of vulcanized elastomers. The decline of brass plating is reviewed. Various methods of adhesion testing are discussed and illustrated. Available organic polymer based adhesives will produce high strength bonds to a wide variety of unvulcanized olefinic elastomers. A single coat adhesive has been developed which provides “maximum performance adhesive bonds” to a variety of unvulcanized elastomers. Factors affecting bonding and “bondability index” for the common elastomers are described. The bonding of vulcanized elastomers is a more difficult task. Present adhesives require mechanical or chemical modification of the surface of the elastomer. Brute force tactics used in conjunction with epoxy‐polyamide, phenolic‐polyvinyl formal, or nitrilephenolic systems have performed well in some applications. The quality of these bonds, however, does not equal those produced to unvulcanized elastomers. With cooperation of the users, the adhesive suppliers are developing newer, more effective products to meet the challenge of the advanced polymers and increasingly severe environments in which they are used.