| 摘要 |
Hydrophilic swollen shaped articles such as contact lenses, plates or filling bodies for surgical purposes, pessaries or diaphragms, are made by cross-linking long-chain linear polymers containing numerous hydrophilic non-ionic groups in a mould which has the shape of the desired article or the shape of a block from which the article is shaped by cutting, the cross-linking being effected so as to obtain, on an average, one cross-link for every 50 to 600 monomeric units of the linear polymer, the process being carried out in the presence of water and/or a water-soluble inert liquid such as ethylene glycol, a poly-alkylene glycol or glycerine constituting 20 to 97% of the total weight of the reaction mixture, the article thereafter being washed with water and then stored in water or an aqueous solution. The hydrophilic groups of the polymer may be hydroxyl, ether, amide, triazole, tetrazole or lactone groups. In examples: (1) a solution of polyvinyl alcohol in water is heated with adipic acid and hydrogen chloride until a hydrogel is obtained; (2) polyvinyl alcohol is partially esterified with methacrylic anhydride and the resulting ester is polymerized in solution in water in the presence of a mixture of potassium persulphate and sodium thiosulphate; (3) triethyleneglycol monomethacrylate and dimethacrylate are copolymerized in a mixture of ethylene glycol and water in the presence of potassium persulphate. |
