| 摘要 |
1,057,458. Ornamenting hydrogel articles. CESKOSLOVENSKA AKADAMIE VED. Sept. 17, 1964 [Sept. 11, 1963], No. 36529/64. Heading B6G. [Also in Division G2] A hydrogel article, such as a contact lens, is coloured or patterned by diffusing into it two chemical agents which react within the interstices of the hydrogel mass to produce a precipitate. For instance, the convex surface of a hydrogel contact lens is laid carefully on the surface level of a 5% by weight aqueous potassium ferric cyanide solution. On to the concave lens surface, a drop of 5% by weight ferrous sulphate solution is applied. Impregnation of both solutions from both surfaces of the lens at the same time causes a Prussian blue precipitate to form in the central part of the lens. Many types of precipitates can be formed within the hydrogel mass; light sensitive precipitates such as silver bromide, which can be exposed, developed and fixed by known photographic processes; and sterility producing precipitates such as silver reduced from a silver salt solution. The hydrogel article may be first impregnated with one chemical agent and the second chemical agent applied to one surface only so that the precipitate is formed at and just below that surface. A suitable hydrogel comprises (percentage by weight) 60% ethylene glycol monomethacrylate, 20% diethylene glycol monomethacrylate, 19% water, 0À3% ethylene glycol bismethacrylate, 0À4% ammonium persulphate and 0À3% potassium pyrosulphite. |
