Tackifiers for elastomers

Abstract

A tackifier system which includes the reaction product of oxirane bearing materials with alkyl phenol novolacs for elastomers of alpha-olefin polymers which are sulfur curable. The invention is directed to reaction products of alkyl phenol novolacs with oxirane bearing materials. The reaction products of alkyl phenol novolacs with oxirane bearing materials have been found to be excellent tackifiers for various types of elastomers. Further, the invention is directed to elastomer compositions containing reaction products of alkyl phenol novolacs with oxirane bearing materials. Elastomer compositions containing the reaction products of alkyl phenol novolac resins with oxirane bearing materials exhibit excellent tack properties. Tackifiers are employed in elastomeric compositions to produce wider practical ranges of elastomer properties, such as stiffness and tack. Tackifiers are used to improve adhesion, and sometimes cohesion without necessarily stiffening or softening the elastomer composition. The tackifiers of the invention are particularly useful in elastomer products which require green tack in their construction. These elastomers include hydrocarbon or hydrocarbon-acrylonitrile, or halohydrocarbon elastomers. Normally-solid elastomers which are alpha-olefin (e.g. monoolefin or diolefin) hydrocarbon polymers which are sulfur curable are becoming increasingly important for producing a variety of useful products. For broader application, however, such elastomers must be adapted to have excellent tack properties. For various applications, it is desirable that elastomers have good tack properties prior to curing, in that for bonding purposes it is desirable that the tack property is sufficient to allow the elastomer to bond, on contact, with a force which is sufficiently high to oppose delaminating forces appearing during the fabrication of elastomer products, but low enough to permit clean separation prior to cure if the need arises. The invention is directed to tackifiers utilized as tire stock tackifiers, cement tackifiers and tackifiers for any rubber application requiring green tack. Examples of rubber products which require good green tack in their construction include tires, belts and hoses.