Irradiation of hydrophilic and hydrophobic monomers to produce hydrophilic copolymers
AssigneeSpecial Polymers Limited
InventorsPhilip William Cordrey, John David Frankland, Donald James Highgate
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Abstract
A hydrophilic polymer or copolymer is produced in an environment free from a chemical initiator and preferably by irradiation of the starting materials, particularly by gamma rays. The product polymer or copolymer is thus free from the residua of chemical initiators and the method permits the production of polymers and copolymers which are particularly suitable for use in contact with living tissue, for example as contact lenses, prosthetic devices, surgical implants, protective corneal fittings and protective membranes or bandages.
Claims15
A method for the production of a hydrophilic copolymer, which comprises subjecting to copolymerization an initial mixture of (a) hydrophilic monomer selected from the group consisting of methacrylic acid, acrylic acid, N-vinyl pyrrolidones, vinyl pyridines, hydroxy alkyl methacrylates and mixtures thereof, and (b) hydrophobic monomer selected from the group consisting of alkyl acrylates, alkyl methacrylates, styrene and diethyleneglycol bis(allyl carbonate) and, as the only monomers in the polymerization system, said monomers being mixed in a molar ratio of a/b in the range of 10/1 to 1/2, in an environment free of chemical polymerization initiator and any residue thereof, by subjecting the initial mixture to electromagnetic radiation in the ultraviolet-gamma ray range using a radiation dosage of from 2 to 5 megarads administered over a time period of from one to 48 hours, to give a degree of polymerization of at least 95%.
Dependencies are inferred from the claim text.