Modifiers for Rubber Compounds

Rubber compounders often add different types of thermoplastics to their formulations to improve or modify certain properties. In particular, thermoplastic impact modifiers can improve cold temperature impact and flexibility making the final rubber compound more robust. There are a number of different impact modifiers that can be utilized, such as polyolefin plastomers and elastomers, olefinic block copolymers, VLDPE, TPOs, sytrenic block copolymers, ethyl or butyl acrylates and EVA. Which impact modifier to use is based on a number of considerations, such as the end use application, desired final properties and performance, processability, compatibility and cost.

In some cases the impact modifier may be “functionalized” with maleic anhydride or glycidyl methacrylate. These modifiers can not only improve the impact performance but also improve compatibility with the rubber and other ingredients in the formulation. Another reason that a functionalized modifier may be used is to help improve adhesion between the rubber compound and another material; for example, to improve adhesion to a polyester fiber layer in a multi-layer hose.

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