Plastic castings molds
AssigneeNovartis AG
InventorsPeter HAGMANN, Axel Heinrich, Willi Hoerner, Robert Allen Janssen, John Martin Lally, Robert Earl Szokolay, Bernhard Seiferling
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Abstract
The invention is concerned with the problem that with known plastic casting moulds, especially those of polypropylene, the lenses produced with these moulds have a slippery surface. The invention solves this problem through the use of polymers which are notable for their very low oxygen permeability.
Claims25
A process for the production of a contact lens, comprising polymerizing and/or crosslinking a starting material in a mold to form the contact lens, wherein the starting material is polymerizable and/or crosslinkable by means of an appropriate energy, wherein the mold has a first mold half having a first optical surface in contact with the starting material and a second mold half having a second optical surface in contact with starting material, wherein said first mold half and said second mold half are configured to receive each other such that the cavity is formed between said first optical surface and said second optical surface, wherein at least one of the first and second mold halves comprises a polymer having a very low oxygen permeability characterized by being less than
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- so that oxygen is prevented from reaching the first and/or second optical surfaces during polymerizing and/or crosslinking process and that inhibition of polymerizing and/or crosslinking of the starting material at starting material/optical surface interface is substantially minimized or eliminated, and wherein the polymer is selected from the group consisting of Terlux KR-2812 (methamethacrylate/acrylonitrile/butadiene/styrene copolymer), Barex 210 (methacrylate/acrylonitrile copolymer), Ticona's Topas® (cyclic olefin copolymers), and CR-39 (diallyl diglycol carbonate polymer).
A process for producing a contact lens, comprising exposing a starting material for producing the contact lens present in a mold to radiation to polymerize and/or crosslink the starting material;
- wherein the mold comprises a first mold half and a second mold half, wherein the first mold half and second mold half are configured to receive each other such that a cavity is formed between the first mold half and second mold half, wherein only the first mold half comprises a polymer having an oxygen permeability less than
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- wherein the polymer comprises a polymer derived from norbornene.
A process for producing a contact lens, comprising exposing a starting material for producing the contact lens present in a mold to radiation to polymerize and/or crosslink the starting material;
- wherein, the mold comprises a first mold half having a first optical surface in contact with the lens material and a second mold half having a second optical surface in contact with lens material, wherein said first mold half and said second mold half are configured to receive each other such that a cavity is formed between said first optical surface and said second optical surface, wherein the cavity defines the shape of a contact lens to be molded, wherein the lens material is polymerizable and/or crosslinkable by means of an appropriate energy, wherein at least one of the mold halves is made from a mold material comprising a polymer selected from the group consisting of Terlux KR-2812 (methamethacrylate/acrylonitrile/butadiene/styrene copolymer), Barex 210 (methacrylate/acrylonitrile copolymer), Ticona's Topas® (cyclic olefin copolymers), CR-39 (chemically crosslinked polymer consisting of allyl diglycol carbonate monomer), wherein the polymer has a very low oxygen permeability characterized by a value of less than
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- so as to be capable of substantially minimizing and/or eliminating inhibition of polymerizing and/or crosslinking of the lens material at interface between the lens material and the first or second optical surface by preventing oxygen from reaching the first or second optical surface during polymerizing and/or crosslinking process.
Dependencies are inferred from the claim text.