Patent ID: 6608117
Filing Date: 2003-08-19
Classification: C08J

Abstract:
A method of preparing hydrogel sponges having collapsed walls, said method comprising the steps of:(I) providing a polymer capable of being physically cross-linked; (II) dissolving said polymer in a material selected from the group consisting essentially of: (i) a single solvent for the polyvinyl alcohol and, (ii) a mixture of solvents for the polyvinyl alcohol, to form a solution; (III) mixing the solution formed in (II) with a pore-forming material; (IV) providing conditions for the mixture of (III) in which the polymer will undergo physical cross linking; (V) bringing the mixture from (IV) to about room temperature; (VI) removing essentially all of the solvents by a method which does not significantly affect the cross-linking or pore-forming material; (VII) heating the mixture at an elevated temperature for a period of from ten seconds to eight hours, and (VIII) cooling the mixture from (VII) to about room temperature and removing the pore-forming material by means which does not significantly affect the cross-linking, whereby a sponge having collapsed walls is obtained.