Patent attributes
A TPV composition having improved fabricability and surface appearance is achieved by a process for preparing a thermoplastic vulcanizate composition having a dispersed, cross-linked rubber phase in a continuous thermoplastic polypropylene phase comprising: a) providing into melt processing equipment at least the following components; i) at least one thermoplastic polypropylene homopolymer or copolymer having a melt temperature greater than 120° C.; ii) 6-12 wt. %, based on the total weight of the thermoplastic vulcanizate composition, at least one propylene copolymer having from 7 to 30 wt. % ethylene, based upon the weight of the random propylene copolymer, and a melting point less than 120° C.; iii) at least one cross-linkable rubber, where, if including an ethylene copolymer rubber, said copolymer rubber having equal to or more than 40 wt. % the total copolymer rubber weight; b) melt processing the blend of i), ii), and iii) of a); c) dynamically vulcanizing the cross-linkable rubber iii) in the presence of the thermoplastic i) and random copolymer ii); and d) removing a thermoplastic vulcanizate product of c) from the melt processing equipment, wherein the dispersed, cross-linked rubber phase of the product thermoplastic vulcanizate d) consists of particles having an effective diameter not greater than 2 millimicrons.
