Method for preparing silicone graft copolymers
AssigneeEssilor International (Compagnie Generale d'Optique)
InventorGeorges H. Wajs
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Abstract
The invention relates to the preparation of graft copolymers from silicones. The method comprises subjecting an article such as a contact lens previously moulded from silicone resins to an UV irradiation step with radiations of wave-length from 1800 to 4000 angstroms, in the presence of oxygen, and in a subsequent step contacting said article with an unsaturated monomer compound at a temperature sufficient to ensure the grafting of said compound on the silicone resin.
Claims14
A method for preparing graft polyorganosiloxanes comprising an irradiating step, wherein an article previously moulded from a polyorgaosiloxane is subjected to a non ionizing UV radiation having a wave-length within the range from 1800 to 4000 Angtroms in the presence of oxygen, the article being exposed to a power intensity of said radiation of about 100 to 1000 mw/cm.sup.2 for a time period of about 5 seconds to 30 minutes and a subsequent grafting step wherein said article is contacted with a monomer selected from compounds having a pyrrolidone ring wherein the nitrogen atom of the heterocyclic ring carries as a substituent a hydrocarbon radical including an ethylenically unsaturated group, whereby said monomer is grafted onto the polyorganosiloxane.
A method for preparing a contact lens adapted to be worn on the cornea comprising moulding a polyorganosiloxane composition into a substrate a generally concave-convex shape, irradiating said substrate in the presence of oxygen with a non ionizing UV radiation having a wave length within the range from 1800 to 4000 Angstroms in the presence of oxygen, and contacting said irradiating substrate with a hydrophillic monomer selected from compounds having a pyrrolidone ring wherein the nitrogen atom of the heterocyclic ring carries as a substituent a hydrocarbon radical including an ethylenically unsaturated group to form a graft copolymer of about 75 to 99% by weight of said polyorganosiloxane composition and about 1 to 25% by weight of said monomer grafted thereto.
Dependencies are inferred from the claim text.