Process of forming a hydroxy-substitute polymeric shaped article
AssigneeMinnesota Mining and Manufacturing Company
InventorsW. James Hammar, Ronald F. Ofstead
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Abstract
A process for preparing shaped articles and shaped hydrogel articles including ophthalmic devices comprises the steps of preparing a polymer or copolymer comprising units derived from an ethylenically-unsaturated monomer bearing at least one trihaloacetoxy-substituent group, thermoforming said polymer by heating in a mold or in sheet-form at a temperature in the range of 100.degree. to 400.degree. C. for about 5 seconds to 15 minutes, and then cooling said polymer, to provide a shaped article, solvolyzing the resulting shaped article to provide a hydroxy-substituted polymeric shaped article, and optionally hydrating said hydroxy-substituted polymeric shaped article to provide a shaped hydrogel article.
Claims39
A process for preparing a hydroxy-substituted polymeric shaped article comprising the steps:
- a. thermoforming an uncrosslinked polymer having a softening temperature of at least 100.degree. C. comprising the product of an ethylenically-unsaturated monomer bearing at least one trihaloacetoxy-substitent group, by heating in a mold or pressing into sheets or films at a temperature in the range of 150.degree. to 400.degree. C. for 5 seconds to 15 minutes, and then cooling the resulting thermoformed polymer, to provide a thermoplastic, hydrogel precursor shaped article,
- b. solvolyzing the shaped article by reacting with a nucleophile which causes displacement of said trihaloacetoxy group to provide a hydroxy-substituted polymeric shaped article, said solvolyzing step taking place in the presence of a diluent which is not a solvent for said thermoformed polymer.
Dependencies are inferred from the claim text.