Ge Plastics Japan Ltd.

General Electric Plastics Japan

Kotaro Kishimura

Tomoaki Shimoda

Takeshi Sakashita

Shuichi Uchimura

The present invention relates to a method for preparing copolymeric polycarbonates which comprises melt polycondensing a mixture of an aromatic dihydroxy compound containing an amount of 2-90 mol % of hydroquinone or substituted hydroquinones and a diester carbonate in the presence of a catalyst containing an alkali metal compound or an alkaline earth metal compound in an amount of 1.times.10.sup.-8 to 5.times.10.sup.-6 mole per mole of the total amount of the aromatic dihydroxy compound, then adding an acidic compound to the melt polycondensation product.

Copolymeric polycarbonate production method

A copolymeric polycarbonate containing repeating constituent units having formula [I] below and repeating constituent units having formula [II] below in a molar ratio of from 98:2 to 40:60. ##STR1## The above-described copolymeric polycarbonates have excellent resistance to chemicals, heat resistance and flame retardancy without compromising the impact resistance and good hues intrinsic to polycarbonates.

Copolymeric polycarbonate compositions containing a sulfonic acid

The method of this invention prepares copolymeric polycarbonates which have excellent mechanical properties, heat resistance and transparency, and which also have improved chemical resistance, hue, and residence stability by inducing the melt polycondensation of an aromatic dihydroxy compound containing an amount of 2-90 mol % of hydroquinone and/or substituted hydroquinones with a diester carbonate in the presence of a catalyst containing alkali metal compounds and/or alkaline earth metal compounds in an amount of 1.times.10.sup.-8 to 5.times.10.sup.-6 mole per mole of the total amount of the aromatic dihydroxy compound.

Method for the preparation, of copolymeric polycarbonates

The present invention relates to a method of preparing a copolymeric polycarbonate which comprises melt-polycondensing a mixture of an aromatic dihydroxy compound comprising hydroquinone or substituted hydroquinones and a diester carbonate in the presence of a catalyst containing alkali metal compounds and/or alkaline earth metal compounds.

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Kwakuni, Japan

Kotaro Kishimura