COMPOSITIONS COMPRISING BLENDS OF POLYNORBORNENE AND POLYOLEFIN RESIN AND A PROCESS FOR MAKING THEM

摘要

Compositions comprising 1-99 parts by weight of crystalline polyolefin resin and correspondingly 99-1 parts weight of polynorbornene per 100 total parts by weight of resin and polynorbornene and enough plasticizer to reduce the glass transition temperature of the polynorbornene to within the rubbery range, typically between 30-400 parts by weight of polynorbornene plasticizer per 100 parts by weight of polynorbornene, are moldable thermoplastic compositions exhibiting improved strength, greater toughness or impact resistance than the components of the blend. Compositions comprising more than 80 parts by weight of crystalline polyolefin resin per 100 parts by weight of polyolefin resin and polynorbornene combined are thermoplastic compositions exhibiting improved impact resinstance. Compositions comprising less than 80 parts by weight of crystalline polyolefin resin are elastoplastic, i.e., they exhibit elastomeric properties yet are processable as thermoplastics. In preferred compositions of the invention the polynorbornene is cross-linked and is dispersed throughout the polyolefin resin as discrete particles having a size 50 microns number average or below. A preferred process for the production of the compositions of the invention in which the polynorbornene is cross-linked comprises masticating a blend of polyolefin resin and polynorbornene with rubber curative at cross-linking temperature until the polynorbornene is cross-linked.