THERMOPLASTIC ELASTOMER BLENDS OF HYDROGENATED POLYBUTADIENE BLOCK COPOLYMERS WITH ALPHA-OLEFIN POLYMERS AND COPOLYMERS AND PROCESS FOR MAKING THESE BLENDS

摘要

Thermoplastic elastomer blends of alpha-olefin polymers and copolymers, such as polypropylene, having a melting point of at least 90 DEG C. with hydrogenated diblock copolymers of 1,4-polybutadiene and 1,2-polybutadiene have good physical properties such as low brittle point, good impact resistance at low temperatures, minimum creep at high temperatures, good elongation, good tensile and tear strengths and good impact strength. The blends can be repeatedly processed and still maintain good physical properties. The amount of alpha-olefin polymer or copolymer in the blend may range from about 10 percent to 60 percent, preferably 15 percent to about 48 percent with the amount of the hydrogenated butadiene block copolymer correspondingly ranging from about 90 percent to about 40 percent, preferably 85 percent to about 52 percent based on the combined weight of the two components. The blends are mixed at temperatures at least as high as the melting point of the alpha-olefin polymers or copolymer.