# US 5,344,875 A · Wear-resistant polyoxymethylene resin composition and method for making same > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,344,875 A - Document ID: US5344875A - Status: Granted - Kind: A - Application number: 08/026,190 - Filed: 1993-03-01 - Granted: 1994-09-06 - Earliest claimed: 1989-11-28 - Assignees: Asahi Kasei Kogyo Kabushiki Kaisha - Inventors: Masahiko Niino - Web page: https://patentgrep.com/patent/US5344875A ## CPC - C08L 59/02: Polyacetals containing polyoxymethylene sequences only - C08G 18/56: Polyacetals - C08L 75/00: Compositions of polyureas or polyurethanes; Compositions of derivatives of such polymers - C08L 23/00: Compositions of homopolymers or copolymers of unsaturated aliphatic hydrocarbons having only one carbon-to-carbon double bond; Compositions of derivatives of such polymers - C08L: COMPOSITIONS OF MACROMOLECULAR COMPOUNDS (compositions based on polymerisable monomers C08F, C08G; artificial filaments or fibres D01F; textile treating compositions D06) - C08G: MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS ## Abstract The present invention provides a polyoxymethylene resin composition which is excellent in wear resistance and is suitable as materials for various sliding parts. The composition comprises (A) 65-98.8% by weight of a polyoxymethylene resin, (B) 0.2-5.0% by weight of a polyfunctional isocyanate compound, (C) 0.5-20% by weight of an olefin polymer containing 30% by weight or more of ethylene and a functional group containing an active hydrogen, and (D) 0.2-10% by weight of polyethylene. ## Claims ### Claim 1 A wear resistant polyoxymethylene resin composition which comprises (A) 65-98.8% by weight based on the total weight of the composition of a polyoxymethylene resin, (B) 0.2-5% by weight based on the total weight of the composition of a trifunctional isocyanate compound, (C) 0.5-20% by weight based on the total weight of the composition of a graft olefin polymer which is obtained by grafting onto an olefin polymer containing 30% by weight or more of ethylene, a copolymer comprising a monomer having a functional group containing an active hydrogen and a comonomer, and (D) 0.2-10% by weight based on the total weight of the composition of polyethylene. ### Claim 2 (depends on 1) The composition according to claim 1, wherein the weight of trifunctional isocyanate compound (B) is 0.5-4.0%. ### Claim 3 (depends on 1) The composition according to claim 1, wherein the olefin polymer containing 30% by weight or more of ethylene is an ethylene copolymer which has an average molecular weight Mn of 20,000-500,000. ### Claim 4 (depends on 1) The composition according to claim 1, wherein the olefin polymer is an ethylene copolymer comprising at least 50% by weight of ethylene. ### Claim 5 (depends on 1) The composition according to claim 1, wherein the polyethylene (D) is a polyethylene having a number-average molecular weight of 20,000-1,000,000, a specific gravity of 0.91-0.98 and a melting point of 100.degree.-140.degree. C. ### Claim 6 (depends on 1) The composition according to claim 1, which further comprises a tertiary amine represented by the formula: ##STR18## wherein R.sup.3, R.sup.4, and R.sup.5, which may be identical or different each represents an unsubstituted or substituted alkyl group of 1-22 carbon atoms, or an unsubstituted or substituted aryl group of 6-22 carbon atoms. ### Claim 7 (depends on 6) The composition according to claim 6, wherein the tertiary amine is present in an amount of 5% by weight or less based on total amount of the composition. ### Claim 8 (depends on 1) A method for producing a wear-resistant polyoxymethylene resin composition of claim 1 which comprises melt-kneading a mixture comprising (A) 65-98.8% by weight of a polyoxymethylene resin, (B) 0.2-5.0% by weight of a trifunctional isocyanate compound, (C) 0.5-20% by weight of a graft olefin polymer which is obtained by grafting onto an olefin polymer containing 30% by weight or moire of ethylene, a copolymer comprising a monomer having a functional group containing an active hydrogen and a comonomer, and (D) 0.2-10% by weight of polyethylene at a maximum resin temperature of 210.degree. C. or higher for 0.5 minute or more. ### Claim 9 (depends on 1) The composition according to claim 1, wherein the polyoxymethylene resin (A) is an oxymethylene homopolymer or an oxymethylene copolymer. ### Claim 10 (depends on 1) The composition according to claim 1, wherein the trifunctional isocyanate compound (B) is a compound having three isocyanate groups or isothiocyanate groups. ### Claim 11 (depends on 1) The composition according to claim 1, wherein the functional group containing an active hydrogen contained in graft olefin polymer (C) is selected from a hydroxy group, a carboxyl group, an amide group, an amino group or a mixture thereof. ### Claim 12 (depends on 1) The composition according to claim 1, wherein the olefin polymer containing 30% by weight or more of ethylene is an ethylene copolymer which has an average molecular weight Mn of 30,000-200,000. ### Claim 13 (depends on 1) The composition according to claim 1, wherein the monomer having a functional group containing an active hydrogen is an .alpha.,.beta.-unsaturated carboxylic acid ester containing a hydroxyl group which is represented by formula (II): ##STR19## wherein R represents a hydrogen atom, an alkyl group or a substituted alkyl group and Y represents an aliphatic hydrocarbon residue, an aromatic hydrocarbon residue, a substituted aliphatic hydrocarbon residue, or a substituted aromatic hydrocarbon residue. ### Claim 14 (depends on 1) The composition according to claim 1, wherein the comonomer is at least one monomer of an .alpha.-olefin other than ethylene, a vinyl carboxylate, an acrylic ester or a methacrylic ester.