US4419463A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Preparation of cross-linked hydrogel copolymers for contact lenses
Assignee: Individual
•
Filing: 1982-03-16
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Granted: 1983-12-06
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Expires: 2002-03-16
Abstract
Abstract The invention relates to soft contact lenses having a water content of at least about 45% and comprising a hydrated copolymer of a major proportion of an hydroxyalkyl acrylate or methacrylate, up to 12% by weight of an ethylenically unsaturated acid or anhydride, a minor proportion of a cross-linking monomer and a minor proportion of styrene or a substituted styrene, the free acid or anhydride groups being in salt form.
Inventors
- 👤 Ivor B. Atkinson
- 👤 Barry C. Holdstock
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 05:24
CPC Classifications
G; G02; G02C; G02C7/00; G02C7/02; G02C7/04; Y; Y10; Y10S; Y10S425/00; Y10S425/808; Y10S526/00; Y10S526/93; Y10S526/936
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
114 words
A method of producing a soft contact lens having a water content of at least about 30% by weight based on the weight of the hydrated lens which comprises: (a) preparing a monomer mixture containing a major proportion of a hydroxyalkyl acrylate or methacrylate, up to 12% by weight of an unsaturated carboxylic acid, a minor proportion of a cross-linking monomer, from about 4 to about 30% by weight of styrene or a substituted styrene and a polymerisation initiator, (b) removing oxygen from mixture, (c) filling the mixture into a suitably-shaped mould and effecting polymerisation in the absence of oxygen and, (d) converting free carboxylic acid groups in the resulting copolymer to salt form.
Claim 2
Independent Claim
114 words
A method of producing a soft contact lens having a water content of at least about 30% by weight based on the weight of the hydrated lens which comprises: (a) preparing a monomer mixture containing a major proportion of a hydroxyalkyl acrylate or methacrylate, up to 12% by weight of an unsaturated carboxylic acid, a minor proportion of a cross-linking monomer, from about 4 to about 30% by weight of styrene or a substituted styrene and a polymerisation initiator, (b) removing oxygen from mixture, (c) filling the mixture into a suitably-shaped mould and effecting polymerisation in the absence of oxygen and, (d) converting free carboxylic acid groups in the resulting copolymer to salt form.
Claim 3
Dependent Claim
48 words
A method according to claim 1 wherein, prior to step (d), the resulting shaped, hard copolymer is machined to form a lens and the lens is then swollen by immersion in an aqueous solution and free carboxylic groups converted to salt form by treatment with a mild alkali.
References Cited (Backward Citations)
US3876581A
Cited
GB1475605A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1986-12-05 | 1987-06-06 | 1987-12-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1990-12-05 | 1991-06-06 | 1991-12-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1994-12-05 | 1995-06-06 | 1995-12-06 | $7700.00 | Window Closed / Lapsed |