METHOD OF PREPARING POLYMER MATERIAL FOR FLEXIBLE CONTACT LENSES Russian patent published in 1998 - IPC

FIELD: polymer materials. SUBSTANCE: material is obtained in polymerization of N-vinylpyrrolidone and methyl methacrylate in presence of divinyl cross-linking agent initiated by ionizing radiation. The latter is provided by consecutive pulses with pauses after each pulse to attain total exposition dose 10.5-14.0 kGray. Pauses before each subsequent pulse beginning with the second one are conducted according to scheme: 2, 6, 12, 24 h, Е, 24 h. EFFECT: reduced residual internal strains in material and improved its optical and physico-mechanical characteristics. 3 cl, 1 tbl, 5 ex