Kanebo, Limited

Osaka Gas Company Limited

Michiaki Fuji

Kenji Yao

Kazuo Sakurai

Koei Igarashi

Toshihiro Kushimoto

Yoshimi Ito

Makoto Hanazawa

The aim of the invention is to stably provide a polyester polymer which has excellent transparency, mechanical and electric characteristics, and extremely low optical anisotropy and excellent moldability and size stability for engineering plastics, particularly suitable for optical materials. The above-mentioned problem can be achieved by a polyester polymer, obtainable from a dicarboxylic acid compound and a dihydroxy compound, and

Polyester polymer, its moldings, and production method of the polyester polymer

A polyester polymer includes a dicarboxylic acid or its ester-forming derivative and a dihydroxy compound, in which the dicarboxylic acid contains an alicyclic dicarboxylic acid and optionally an aromatic dicarboxylic acid, and the dihydroxy compound contains a compound of formula (1): ##STR1## wherein R.sub.1 represents a C.sub.1-4 alkylene group; and R.sub.2, R.sub.3, R.sub.4 and R.sub.5 each represents a hydrogen atom, a C.sub.1-4 alkyl group, an aryl group or an aralkyl group which may be the same or different. Also, polyester moldings of disc substrates, lenses, sheets, films, tubes or fibers are produced by molding the polyester polymer. The polyester polymer has excellent transparency, excellent heat resistance, extremely low optical anisotropy and excellent moldability.

Polyester polymer and its moldings

Polyester containing 9,9-bis(4-(2-hydroxyalkoxy)phenyl fluorene

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Kyoto, Japan

Michiaki Fuji