Method of modifying the physical properties of urethane elastomers
AssigneeDow Corning Corporation
InventorsLawrence A. Rauner, Joseph A. Colquhoun
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Abstract
A method of modifying the physical properties of urethane elastomers so that the properties of the urethane are enhanced. The method involves reacting a specific siloxane-polyoxyalkylene into a urethane elastomer.
Claims14
A method of modifying the physical properties of urethane elastomers which method consists of (I) introducing into an uncured urethane elastomer from 5.1 to 36 weight percent, based on the weight of the urethane and siloxane-polyoxyalkylene copolymer, a siloxane-polyoxyalkylene copolymer selected from the group consisting of ##STR4## wherein each x has an average value of 3 to 45, each y has an average value of 8 to 198, Me is a methyl radical, wherein --OR--.sub.x is a polyoxyalkylene polymer or copolymer wherein R is composed of ethylene radicals or butylene radicals and mixtures of ethylene or butylene radicals with propylene radicals, the amount of ethylene or butylene radicals relative to the propylene radicals being such that the ratio of carbon atoms to oxygen atoms in the total --OR-- block ranges from 2.0/1 to 2.9/1, which siloxane-polyoxyalkylene copolymer is prepared by the process which consists essentially of reacting a dihydroxy functional linear dimethylpolysiloxane with a dihydroxy functional polyoxyalkylene polymer, wherein the hydroxy groups on the polyoxyalkylene polymer are primary hydroxyl groups and where the mole ratio of the hydroxy on the polyoxyalkylene polymer to the hydroxy on the linear dimethylpolysiloxane is 2:1 to 0.5:1, in a solvent solution at 40-75 percent solids based on the total weight of the dimethylpolysiloxane, polyoxyalkylene polymer and solvent, in the presence of a non-rearranging acid condensation catalyst at a temperature of 80.degree.-130.degree. C. for a period of 3-15 hours,
- (II) curing the urethane polymer whereby the siloxane polyoxyalkylene copolymer is reacted into the urethane polymer, thereby modifying the physical properties of the urethane polymer.
A composition of matter which consists of (A) a curable urethane elastomer;
- (B) from 5.1 to 36 weight percent based on the weight of the total composition, of a siloxane-polyoxyalkylene copolymer selected from the group consisting of ##STR5## wherein each x has an average value of 3 to 45, each y has an average value of 8 to 198, Me is a methyl radical, wherein --OR--.sub.x is a polyoxyalkylene polymer or copolymer wherein R is composed of ethylene radicals or butylene radicals and mixtures of ethylene or butylene radicals with propylene radicals, the amount of ethylene or butylene radicals relative to the propylene radicals being such that the ratio of carbon atoms to oxygen atoms in the total --OR--.sub.x block ranges from 2.0/1 to 2.9/1, which siloxane-polyoxyalkylene copolymer is prepared by the process which consists essentially of reacting a dihydroxy functional linear dimethylpolysiloxane with a dihydroxy functional polyoxyalkylene polymer, wherein the hydroxy groups on the polyoxyalkylene polymer are primary hydroxyl groups and where the mole ratio of the hydroxy on the polyoxyalkylene polymer to the hydroxy on the linear dimethylpolysiloxane is 2:1 to 0.5:1, in a solvent solution at 40-75 percent solids based on the total weight of the dimethylpolysiloxane, polyoxyalkylene polymer and solvent, in the presence of a non-rearranging acid condensation catalyst at a temperature of 80.degree.-130.degree. C. for a period of 3-15 hours.
A composition of matter which consists of (A) a cured urethane elastomer containing therein (B) from 5.1 to 36 weight percent based on the weight of the total composition, of a siloxane-polyoxyalkylene copolymer selected from the group consisting of ##STR6## wherein each x has an average value of 3 to 45, each y has an average value of 8 to 198, Me is a methyl radical, wherein --OR--.sub.x is a polyoxyalkylene polymer or copolymer wherein R is composed of ethylene radicals or butylene radicals and mixtures of ethylene or butylene radicals with propylene radicals, the amount of ethylene or butylene radicals relative to the propylene radicals being such that the ratio of carbon atoms to oxygen atoms in the total --OR-- block ranges from 2.0/1 to 2.9/1, which siloxane-polyoxyalkylene copolymer is prepared by the process which consists essentially of reacting a dihydroxy functional linear dimethylpolysiloxane with a dihydroxy functional polyoxyalkylene polymer, wherein the hydroxy groups on the polyoxyalkylene polymer are primary hydroxyl groups and where the mole ratio of the hydroxy on the polyoxyalkylene polymer to the hydroxy on the linear dimethylpolysiloxane is 2:1 to 0.5:1, in a solvent solution at 40-75 percent solids based on the total weight of the dimethylpolysiloxane, polyoxyalkylene polymer and solvent, in the presence of a non-rearranging acid condensation catalyst at a temperature of 80.degree.-130.degree. C. for a period of 3-15 hours.
Dependencies are inferred from the claim text.