Polyurethane hydrogels and process for their manufacture
AssigneeEssilor International
InventorsYves Gnanou, Gerard Hild
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Abstract
The hydrogels consist essentially of the polyurethane of polyoxyethylene. The crosslinking is carried out by a reaction of a polyfunctional isocyanate with the polyoxyethylene in solution in a non-aqueous solvent. Transparent hydrogels are obtained, having a high swelling ratio in the presence of water and good mechanical properties.
Claims21
A molded article of a polyurethane hydrogel comprising a polyoxyethylene polyurethane one step crosslinking reaction product of a polyfunctional isocyanate with a polyoxyethylene in solution in a non-aqueous solvent which is substantially non-reactive for said polyisocyanate essentially in absence of water in an inert atmosphere to yield a gel swollen by the non-aqueous solvent.
A molded article of a transparent polyurethane hydrogel, containing from 70 to 97% by weight of water at its swelling equilibrium in water, and not more than 5% by weight extractible content and having an elasticity modulus of 10.sup.5 to 3.10.sup.6 dynes/cm.sup.2.
Dependencies are inferred from the claim text.