# US 6,294,638 B1 · Soft, transparent and processable thermoplastic polyurethane > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 6,294,638 B1 - Document ID: US6294638B1 - Status: Granted - Kind: B1 - Application number: 09/415,341 - Filed: 1999-10-08 - Granted: 2001-09-25 - Earliest claimed: 1999-10-08 - Assignees: Bayer Aktiengesellschaft - Inventors: Steven C. Manning; Charles S. Gracik; Arthur W. Mason; Jack C. Chan - Web page: https://patentgrep.com/patent/US6294638B1 ## CPC - C08G 18/6674: {with compounds of group C08G18/3203} - C08G: MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS ## Abstract A soft, transparent and processable thermoplastic polyurethane resin suitable in optical application is disclosed. The resin is the product of reacting a diisocyanate, a chain extender, and a mixture of polyether polyols. The mixture of polyether polyols comprise (A) a C4 polyether polyol and (B) a C2-C3 polyether polyol where the weight ratio A/B is in the range of about 85/15 to 15/85. ## Claims ### Claim 1 A soft, transparent and processable thermoplastic polyurethane resin having a shore A hardness of about 60 to 80, prepared by reacting (i) about 15 to 45% of at least one duisocyanate, and (ii) 3 to 15% of at least one chain extender, and (iii) 40 to 80% of a mixture of polyether polyols, said percents being in relation to the total weight of (i), (ii) and (iii), said mixture of polyether polyols comprising (A) a C4 polyether polyol having a number average molecular weight of about 500 to 2500 g/mol conforming structurally to HO—(CH2—CH2—CH2—CH2—O)n—H and (B) a C2-C3 polyether polyol having a number average molecular weight of about 2100 to 6000 g/mol, conforming structurally to where x and z independently denote integers of 1 to 10 and where y denotes an integer of 35 to 80, and where the weight ratio A/B is in the range of about 85/15 to 30/70. ### Claim 2 (depends on 1) The thermoplastic polyurethane resin of claim 1 wherein said resin is prepared by reacting (i) about 25 to 35% of at least one diisocyanate, and (ii) 5 to 12% of at least one chain extender, and (iii) 55 to 65% of a mixture of polyether polyols, said percents being in relation to the sum total of (i) (ii) and (iii). ### Claim 3 (depends on 1) The thermoplastic polyurethane resin of claim 1 wherein said C4 polyether polyol has a number average molecular weight of about 800 to 1200 g/mol. ### Claim 4 (depends on 1) The thermoplastic polyurethane resin of claim 1 wherein said C2-C3 polyether polyol has a number average molecular weight of about 3500 to 4500 g/mol. ### Claim 5 (depends on 1) The thermoplastic polyurethane resin of claim 1 wherein said ratio of A/B is about 70/30 to 30/70. ### Claim 6 (depends on 1) The thermoplastic polyurethane resin of claim 1 wherein shore A hardness is about 70 to 78. ### Claim 7 A soft, transparent and processable thermoplastic polyurethane resin having a shore A hardness of about 70 to 78, prepared by reacting (i) about 25 to 35% of at least one diisocyanate, and (ii) 5 to 12% of at least one chain extender, and (iii) 55 to 65% of a mixture of polyether polyols, said percents being in relation to the total weight of (i), (ii) and (iii), said mixture comprising as reactant (A) a C4 polyether polyol having a number average molecular weight of about 800 to 1200 g/mol conforming structurally to HO—(CH2—CH2—CH2—CH2—O)n—H and (B) a C2-C3 polyether polyol having a number average molecular weight of about 3500 to 4500 g/mol, conforming structurally to where x and z independently denote integers of 7 to 9, and where y denotes 50 to 60 and wherein the weight ratio of A/B is in the range of about 70/30 to 30/70. ### Claim 8 (depends on 1) The thermoplastic polyurethane resin of claim 1 wherein diisocyanate is aliphatic. ### Claim 9 (depends on 8) The thermoplastic polyurethane resin of claim 8 wherein aliphatic diisocyanate is at least one member selected from the group consisting of 4,4′-diisocyanatodicyclohexyl methane, 1,6-hexamethylene diisocyanate, hydrogenated 4,4′-biphenyl diisocyanate, isophorone diisocyanate and cyclohexane diisocyanate. ### Claim 10 (depends on 8) The thermoplastic polyurethane resin of claim 8 wherein aliphatic diisocyanate is 4,4′-diisocyanatodicyclohexyl methane. ### Claim 11 (depends on 8) The thermoplastic polyurethane resin of claim 8 wherein chain extender is at least one member selected from the group consisting of ethylene glycol, butylene glycol, diethylene glycol, triethylene glycol, 1,2-propanediol, tripropylene glycol, neopentyl glycol, propylene glycol, 1,4 butanediol, dicyclohexylmethanediamine, ethylene diamine, propylene diamine and isophorone diamine. ### Claim 12 (depends on 11) The thermoplastic polyurethane resin of claim 11 wherein chain extender is at least one member selected from the group consisting of ethylene glycol, diethylene glycol, 1,4 butanediol and 1,6-hexanediol. ### Claim 13 A soft, transparent and processable thermoplastic polyurethane resin having a shore A hardness of about 70 to 78, prepared by reacting (i) about 25 to 35% of at least one aliphatic diisocyanate, and (ii) 5 to 12% of at least one chain extender selected from the group consisting of ethylene glycol, diethylene glycol, 1,4 butanediol and 1,6-hexane diol, and (iii) 55 to 65% of a mixture of polyether polyols, said percents being in relation to the total weight of (i), (ii) and (iii), said mixture of polyether polyols comprising (A) a C4 polyether polyol having a number average molecular weight of about 800 to 1200 g/mol conforming structurally to HO—(CH2—CH2—CH2—CH2—O)n—H and (B) a C2-C3 polyether polyol having a number average molecular weight of about 3500 to 4500 g/mol, conforming structurally to where x and z independently denote integers of 7 to 9, and where y denotes 50 to 60 and wherein the weight ratio of A/B is in the range of about 70/30 to 30/70.