Use of a silane grafted polyolefin in EPDM/polyolefin thermoplastic vulcanizates to improve compression set
AssigneeAdvanced Elastomer Systems, L.P.
InventorsSabet Abdou-Sabet, Robert E. Medsker, Raman Patel
Life of this patent
Estimating the term…
Abstract
A thermoplastic vulcanizate (TPV) from a blend of a first thermoplastic polyolefin, a second thermoplastic olefin and a rubber is described. The rubber is crosslinked with a hydrosilylation crosslinking agent. The second polyolefin includes at least one OR group pendant to a Si atom chemically attached via one or more intermediate molecules to said second polyolefin. R can be hydrogen or an alkyl of 1 to 8 carbon atoms. The OR groups can react with the hydrosilylation catalyst to reduce the compression set of the TPV.
Claims16
A thermoplastic elastomer composition, comprising
- a) a melt processable semi-crystalline thermoplastic polyolefin which is substantially inert to the other components of the composition,
- b) an unsaturated rubber which has been fully crosslinked by dynamic vulcanization with a hydrosilylation crosslinking agent and hydrosilylation catalyst, and is interdispersed as fine particles within said thermoplastic polyolefin, and
- c) a semi-crystalline thermoplastic functionalized polypropylene with at least one —(OR) group pendant directly from an Si atom, which Si atom is chemically attached via one or more intermediate molecules to said polypropylene, wherein R is a hydrogen or an alkyl of 1 to 8 carbon atoms, said functionalized polypropylene having been exposed to said hydrosilylation catalyst and bonded to said hydrosilylation crosslinking agent, and wherein said functionalized polypropylene is present from about 0.1 to about 25 weight percent of the combined weight of said thermoplastic polyolefin and functionalized polypropylene.
A process for preparing a thermoplastic vulcanizate
- composition, comprising:
- blending in any order
- a) a semi-crystalline thermoplastic polyolefin which is substantially inert to the other components of the composition;
- b) an unsaturated rubber;
- c) a semi-crystalline thermoplastic functionalized polypropylene, present in an amount from about 0.1 to about 25 weight percent based on the combined weight of said thermoplastic polyolefin and functionalized polypropylene, including at least one OR group bonded to a silicon atom pendantly attached to said functionalized polypropylene wherein R is a hydrogen or an alkyl of 1 to 8 carbon atoms;
- and
- d) a hydrosilylation crosslinking agent and hydrosilylation catalyst;
- chemically bonding at least a portion of said functionalized polypropylene to said hydrosilylation crosslinking agent, and fully crosslinking by dynamic vulcanization said rubber with said hydrosilylation crosslinking agent and said hydrosilylation catalyst, to form a dispersion of fine rubber particles within said thermoplastic polyolefin,
- wherein said blending, chemically bonding, and crosslinking steps need not be in any particular order and any one or more steps can occur concurrently.
Dependencies are inferred from the claim text.