I-tek, Inc.

Gaf Corporation

Herman S Schultz

Donald H Lorenz

Earl P Williams

The process for increasing the molecular weight of poly-N-vinylpyrrolidone over that normally obtained by suspension polymerization of N-vinylpyrrolidone in a saturated hydrocarbon suspension medium, by adding to the suspension medium a controlled amount of water, specifically an amount between about 1% and 35% by weight based on the total weight of N-vinylpyrrolidone monomer. The significantly higher molecular weight of the resulting polymeric product can be still further increased by additionally incorporating in the suspension medium between about 0.001 mol % and about 1 mol % of a difunctional vinyl cross-linking agent per mol of N-vinylpyrrolidone monomer. The polymeric products of the present invention are preferably water soluble granules having a porous structure; although the present invention also concerns the poly-N-vinylpyrrolidone having a number average molecular weight of between 400,000 and 2,000,000, preferably between 450,000 and 1,500,000 in any physical form.

Process for increasing molecular weight of vinylpyrrolidone polymer

A hydrophilic copolymer of N,N-(C.sub.1 -C.sub.2 alkyl) acrylamide is disclosed. The copolymer is formed by reacting, based on 100 parts, from 20-80 parts of the C.sub.1 -C.sub.2 alkyl substituted acrylamide, 80-20 parts of C.sub.1 -C.sub.4 alkyl acrylates, methacrylates, or combinations, and small amounts of a cross-linking agent. The resulting copolymerization product can be equilibrated with water or other aqueous solutions to form hydrogels useful in forming shaped hydrogel articles. One particular shaped article which can be formed is a hydrophilic contact lens. A process for forming the hydrogels is also disclosed.

Hydrophilic copolymer of N,N-(C.sub.1 -C.sub.2 alkyl) acrylamide

A hydrophilic copolymer of an N,N-di(C.sub.1 -C.sub.2 alkyl)acrylamide is disclosed. The copolymer is formed by reacting, based on 100 parts, from about 20-80 parts of a C.sub.1 -C.sub.2 alkyl substituted acrylamide, about 10-80 parts of a C.sub.1 -C.sub.4 alkyl acrylate, methacrylate, or combinations of acrylate and methacrylate, and about 2-20 parts of a glycidyl ester of acrylic, methacrylic or crotonic acid. The resulting copolymerization product can be equilibrated with water or other aqueous solutions to form hydrogels useful in forming shaped hydrogel articles. One particular shaped article which can be formed is a hydrophilic contact lens. A process for forming the hydrogels is also disclosed.

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Lexington, MA, United States of America

Herman S Schultz