Idemitsu Petrochemical Co., Ltd.

Takashi Kanezaki

Masaya Okamoto

Yutaka Tsubokura

Kazuo Sato

Tuneaki Kohsaka

A polycarbonate-polydimethylsiloxane copolymer, the copolymer comprising a polycarbonate block of the formula ##STR1## wherein R.sup.1 and R.sup.2 are hydrogen or a C.sub.1 -C.sub.4 alkyl, R.sup.3 and R.sup.4 are hydrogen, halogen, a C.sub.1 -C.sub.20 alkyl or an aryl, x is 1 to 5, y is to 4 and n is 1 to 100, and a polydimethylsiloxane block of the formula ##STR2## wherein R.sup.5 and R.sup.6 are an organic residue having an aromatic nucleus and m is greater than or equal to 100, the copolymer having a content of the polydimethylsiloxane block of 0.5 to 10% by weight, an n-hexane soluble matter content in an amount of 1.0% by weight or less and a viscosity average molecular weight of 10,000-50,000. The copolymer has a high impact resistance and when blended with a glass fiber or a carbon fiber forms a molded product having an extremely high Izod impact strength.

Resin composition containing a polycarbonate-polydimethylsiloxane

The rubber-modified styrene-based resin composition, which is a composite of a styrene-based resin as a continuum of the matrix phase and a diene-based rubbery polymer as a dispersed particulate phase in the matrix, is characterized by the parameters including an average particle diameter of the particles of the rubbery polymer in the range from 0.08 to 1.00 .mu.m, peripheral parameter thereof in the range from 0.1 to 2.5 (.mu.m).sup.-1. (% by weight).sup.-1 and relaxation time T.sub.2 thereof in the range from 300 to 2000 .mu. seconds as the determinant factors of the moldability of the resin composition as well as the impact strength and surface gloss of the shaped articles prepared from the composition.

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Sodegaura, Japan

Takashi Kanezaki