Patent ID: 6774186
Filing Date: 2004-08-10
Classification: C08K,C08L

Abstract:
A process for preparing a rheology-modified, substantially gel-free TPE composition, the process comprising: a) adding at least one peroxide and at least one free radical coagent to a molten polymer blend that comprises an elastomeric ethylene/alpha-olefin polymer and a high melting polymer selected from the group consisting of polypropylene homopolymers and propylene/ethylene copolymers; and b) maintaining the polymer blend in a molten state while subjecting it to conditions of shear sufficient to disperse the peroxide and coagent throughout the molten polymer blend, effect rheology modification of the polymers and substantially preclude formation of insoluble polymer gels, sufficient rheology modification being measured by a melt toughness of at least about 600 cNmm/s, a true ultimate tensile strength at 140Â° C. of at least about 3 MPa and an elongation to break at 140Â° C. of least about 400%.