POLYCARBONATE RESIN MATERIAL FOR MOLDING EYEGLASS LENSES AND OPTICAL ELEMENTS

摘要

Eyeglass lenses made from a polycarbonate resin composition which comprises (1) 100 parts by weight of a polycarbonate resin, (2) 0.05 to 0.5 part by weight of at least one ultraviolet absorber (A) selected from the group consisting of 2-(2'-hydroxy-5' -methylphenyl)benzotriazole and 2-(2'-hydroxy-5'-tert-octyl- phenyl)benzotriazole, (3) 0.01 to 0.3 part by weight of at least one ultraviolet absorber (B) selected from the group consisting of 2-(3-tert-butyl-5-methyl-2-hydroxyphenyl)-5-chlorobenzo- triazole, 2,2'-methylenebis[4-(1,1,3,3-tetramethylbutyl)-6- (2H-benzotriazol)-2-ylphenol] and 2-[2-hydroxy-3,5-bis(α,α- dimethylbenzyl)phenyl]-2H-benzotriazole, and (4) 0.01 to 0.5 part by weight of a full ester (C) which is made from a tetra- to octa-hydric aliphatic C5-30 alcohol and an aliphatic C10-22 carboxylic acid and which has an acid value of 4 to 20. The polycarbonate resin composition has satisfactory heat resistance to withstand the long-term exposure to high -temperature conditions employed in molding lenses by extrusion compression molding or the like and causes little hue change even when has undergone a thermal history (such as re-extrusion) for the re-use of scrap. Further, the composition can give polycarbonate resin eyeglass lenses with excellent mold release characteristics.