| abstract |
PURPOSE: To obtain the title copolymer improved in refractive index, Abbe's number, transparency, etc., by constituting it from a specified acid component and a binary diol component. n CONSTITUTION: The title polymer copolymer for optical materials is a polyester comprising an acid component comprising naphthalene-2,6-dicarboxylic acid and a glycol component comprising a binary system of 1,4-cyclo hexanedimethanol (A) (usually, one having a trans/cis ratio of 70/30) and ethylene glycol (C) and having an A to B molar ratio of 50/50≤A/B≤82/18 and a refractive index n>1.6 and an Abbe's number ν>30. By using this copolymer, a plastic lens excellent in colorlessness and transparency and low in molding stress can be produced. Said polyester can be produced by using a tran sesterification catalyst such as calcium acetate and a Ge-base polycondensation catalyst such as GeO 2 . n COPYRIGHT: (C)1989,JPO&Japio |