Polyurethane hydrogel and method for the production of the same
First Claim
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1. A polyurethane hydrogel obtained by dispersing:
- (a) a reaction product obtained by the reaction of polyisocyanate having at least two isocyanate groups with a polyether into(b) an aqueous liquid phase;
wherein the amounts of said (a) and (b) are such that the hydrogel product has a water content of 70 to 95% by weight and wherein said polyether is produced from a plurality of alkylene oxides, 75 to 85% by weight of which is ethylene oxide, added at random to a polyalcohol having at least two terminal hydroxyl groups in an amount to produce an average molecular weight of 2000 to 3000 per said terminal hydroxyl group of said polyalcohol.
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Abstract
The improved polyurethane hydrogel is produced by dispersing a reaction product obtained by the reaction of a polyisocyanate having at least two isocyanate groups with a polyether. The polyether comprises a plurality of alkylene oxides, 50 to 90% by weight of which is ethylene oxide, added at random to a polyalcohol having at least two terminal hydroxyl groups in an amount of an average molecular weight within the range of 1,000 to 4,000 per said hydroxyl terminal group of said polyalcohol. The improved polyurethane hydrogel can have a greater water content and is highly stable and highly elastic.
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Citations
20 Claims
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1. A polyurethane hydrogel obtained by dispersing:
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(a) a reaction product obtained by the reaction of polyisocyanate having at least two isocyanate groups with a polyether into (b) an aqueous liquid phase; wherein the amounts of said (a) and (b) are such that the hydrogel product has a water content of 70 to 95% by weight and wherein said polyether is produced from a plurality of alkylene oxides, 75 to 85% by weight of which is ethylene oxide, added at random to a polyalcohol having at least two terminal hydroxyl groups in an amount to produce an average molecular weight of 2000 to 3000 per said terminal hydroxyl group of said polyalcohol. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. A method for the production of a polyurethane hydrogel comprising dispersing:
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(a) a reaction product obtained by the reaction of polyisocyanate having at least two isocyanate groups with a polyether, into (b) an aqueous liquid phase to form a hydrogel; wherein the amounts of said (a) and (b) are such that the hydrogel product has a water content of 70 to 95% by weight and wherein said polyether is produced from a plurality of alkylene oxides, 75 to 85% by weight of which is ethylene oxide, added at random to a polyalcohol having at least two terminal hydroxyl group in an amount to produce an average molecular weight of 2000 to 3000 per said terminal hydroxyl group of said polyalcohol. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20)
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Specification