| 摘要 |
PROBLEM TO BE SOLVED: To obtain a contact lens having a high water content, flexibility and excellent long-term stability by grinding and polishing a copolymer comprising vinyl acetate and diallylidenepentaerythrite to form a lens and hydrolyzing the lens. SOLUTION: A crosslinked polyvinyl alcohol soft contact lens having a water content of 20-80 is produced by grinding and polishing a copolymer comprising 90-99.5wt.% vinyl acetate and 0.05-10wt.% diallylidenepentaerythrite under sprinkling with chilled water and hydrolyzing the lens. In this production, the above copolymer is shaped under cooling because it is soft and it is usually difficult to shape the copolymer into a lens by grinding and polishing at room temperature. For instance, it is cooled to -20 deg.C and shaped into a lens under cooling. Although the hydrolysis method is not particularly limited, the hydrolysis is performed by immersing the copolymer in an aqueous alkali solution. An article having flexibility and excellent long-term stability can be obtained. |
