Ophthalmic lenses
AssigneeGreat Lakes Chemical Corporation
InventorsWilliam Bos, Ricardo Henry Breeveld
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Abstract
The present invention relates to the use of metal organic compounds in a process for providing a moulded plastic article comprising the step of polymerization casting of a curable composition comprising one or more polymerizable molecules or compounds or compositions in the presence of a mould release agent, which in turn comprises a metal organic compound, complexes and/or salts thereof. Such use leads to less surface defects of the moulded article and lower mould damage.
Claims24
A process for preparing ophthalmic lenses comprising the steps of:
- polymerizing a polymerizable composition in the presence of a mould release agent in a casting mould;
- the mould release agent comprising at least one of:
- a metal organic compound, a metal organic complex, and a salt thereof, wherein the metal of the mould release agent has an electronegativity of 1.5 to 1.75, when calculated according to the method of Allred and Rochow, and is not Si or P;
- opening the casting mould to release an ophthalmic lens;
- and
- imbibing the ophthalmic lens, after releasing from the casting mold, in a tinting solution to recover a tinted ophthalmic lens substantially free of surface defects including ferns and tinting failures.
A process for preparing ophthalmic lenses comprising the steps of:
- polymerizing a polymerizable composition in the presence of a mould release agent in a casting mould;
- the mould release agent comprising a metal organic compound, wherein the metal of the mould release agent has an electronegativity of 1.5 to 1.75, when calculated according to the method of Allred and Rochow, and is not Si or P,
- wherein the metal organic compound is selected from the group consisting of the formula I-III:
- wherein M is the metal as defined, X=O or S, and R1-R8 are selected from the group consisting essentially of hydrogen, halogen, octoate, laureate, butyl, hexanoate, and decanoate, and
- releasing an ophthalmic lens from the casting mould.
Dependencies are inferred from the claim text.