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.
Claims15
A plastic mold for making a contact lens, comprising 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 the first mold half is permeable to UV light and the second mold half is capable of absorbing UV light having a wavelength greater than 280 nm, wherein the first mold half and second mold half each have an edge, 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 received mold halve edges define a contact zone, 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 cyclic olefin copolymers or a 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.
A mold for producing a contact lens comprising a first mold half and a second mold half, wherein the first mold half and second mold half each have an edge, 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 the received mold halve edges define a contact zone, 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, wherein the first mold half is permeable to UV light and the second mold half is capable of absorbing UV light having a wavelength greater than 280 nm.
Dependencies are inferred from the claim text.