1380884 Thermoplastic olefin polymer blends UNIROYAL Inc 20 Jan 1972 [12 Aug 1971] 2822/72 Heading C3P Thermoplastic blends comprise a partially dynamically cured blend of a monoolefin copolymer rubber and a polyolefin plastic. The rubber may be a copolymer of ethylene, a C 3-14 -olefin and optionally a polyene, e.g. butadiene, isoprene, hexadiene-1,4, dicyclopentadiene, methylene norbornene, ethylidene norbornene, cyclooctadiene or methyl tetrahydroindene. The plastic may be a polymer of ethylene, propylene, butene-1, pentene-1 or 4-methylphentene-1. The partial cure may be effected by masticating or shearing in the presence of organic peroxides, azidoformates, aromatic polyazides and sulphonazides, aldehyde/amine reaction products, substituted ureas guanidines, xanthates, dithiocarbamates, thiazoles, imidazoles, quinone dioximes and sulphur. When the desired partial cure has been effected further curing may be prevented by adding an antixodiant. Examples describe the curing of blends of ethylene/propylene/dicyclopentadiene, ethylene/propylene/ethylidene norbornene or ethylene/propylene rubbers with polypropylene or polyethylene, using 2,5-di- (t.butylperoxy) - 2,5 - dimethyl hexane or dicumyl peroxide, optionally with sulphur, tetramethyl thiuram disulphide or 4,4SP1/SP-dithiodimorpholine as accelerator and tris-(nonylphenyl) phosphite or dilauryl thiodipropionate as antioxidant, and optionally in the presence of titanium dioxide, silica, carbon black and lubricants, e.g. epoxidized soya bean oil, ethylene/methacrylic acid ionomer resin,thermo plastic polyurethane or polyethylene glycol.