Idemitsu Kosan Company, Limited

Takashi Nakagawa

Shuji Sakamoto

Norio Ogata

Yusuke Iseki

Kazuyoshi Shigematsu

Dihydric phenol suitable for the preparation of polycarbonates are represented by the following formula: ##STR1##

Dihydric phenols

A polycarbonate polymer containing repeating units represented by the following general formula ##STR1## wherein: X is selected from single bond, ##STR2## wherein: R.sup.1 and R.sup.2 are each independently selected from hydrogen atom; alkyl radical of 1 to 6 carbon atoms; cycloalkyl radical of 5 to 6 carbon atoms; ##STR3## wherein p is an integer having a value of from 0 to 3; phenyl radicals substituted at para position by a substituent selected from alkoxy radicals of 1 to 5 carbon atoms, phenoxy radicals, or halogen radicals; or p-biphenylyl radical, --CH.sub.2).sub.q wherein q is an integer having a value of from 2 to 10; or ##STR4## wherein r is an integer having a value of from 4 to 8, and having a reduced viscosity [.eta.sp/c] of at least 0.2 dl/g as measured in methylene chloride at a concentration of 0.5 g/dl at 20.degree. C. Such polycarbonates exhibit excellent optical properties such as high birefringence, and are useful as materials for optical devices. Also, a process for preparing the polycarbonates and novel dihydric phenols which can be used as materials for the polycarbonates are disclosed.

Polycarbonate containing compound from bis(3-phenyl-4-hydroxyphenyl)

A process for the production of polyesterpolycarbonate is described, which comprises reacting an aqueous alkaline solution of dihydric phenol and an organic solvent solution of acid chloride to prepare polyester oligomer, mixing chloroformate group-containing polycarbonate oligomer with the polyester oligomer, and polycondensing the polyester oligomer and the polycarbonate oligomer to form the polyesterpolycarbonate.

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Sodegaura, Japan

Takashi Nakagawa