Plastic and nonmetallic article shaping or treating: processes – Optical article shaping or treating – Utilizing plasma – electric – electromagnetic – particulate – or...
Patent
1975-12-15
1977-10-18
Lowe, James B.
Plastic and nonmetallic article shaping or treating: processes
Optical article shaping or treating
Utilizing plasma, electric, electromagnetic, particulate, or...
264102, 264236, 264336, 264337, 264338, 264343, B29D 1100, B29C 700, B29C 2500
Patent
active
040546241
ABSTRACT:
A contact lens composition, having improved dimensional stability, suitable for use in the preparation of a corrective hydrated lens or an eye bandage, comprises polymerized random graft copolymers containing (in the dry state) from 67.2% to 79.3% HEMA; from 14.25% to 35% PVP; from 0.1% to 4.04% EDMA; from 0.1% to 2.5% MA; from 0.1% to 5.0% water; from 0 to 4 ppm HQ inhibitor; and from 50 to 250 ppm MEHQ inhibitor. The contact lens composition contains from 45% to 65% water after hydration. An improved method for shaping, polymerizing, and cutting and hydrating the contact lens composition is provided. The polymerization is conducted using only a low temperature initiator, by de-gassing prior to polymerization to remove substantially all oxygen, and by conducting the initial polymerization reaction at from 23.degree. C to 30.degree. C for 16 to 30 hours, during which the heat of the reaction is continuously absorbed to control the reaction exotherm. A closed, rod-shaped casting mold, lined with a polyester film material, is used and the polymeric rod obtained may be cut, machined and polished to obtain the contact lens composition. Thereafter, hydration is conducted in a buffered, 0.85% to 0.9% saline solution, at a pH of 7.0 to 7.1.
REFERENCES:
patent: 3621079 (1971-11-01), Leeds
patent: 3639524 (1972-02-01), Selderman
patent: 3807398 (1974-04-01), Grucza
patent: 3822196 (1974-07-01), O'Driscoll et al.
patent: 3894129 (1975-07-01), Hoffman et al.
Grovesteen William R.
Le Boeuf Albert R.
Chow Frank S.
Graddis Albert H.
Kelly Anne M.
Lowe James B.
Warner-Lambert & Company
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