Kureha Kagaku Kogyo Kabushiki Kaisha

Hiroshi Hagiwara

Takayuki Katto

Takao Iwasaki

Yoshihiko Kudo

Toshio Hosokawa

Yasumasa Komatsu

Katsumi Suzuki

Yosuke Takahashi

A thermoplastic resin composition is prepared by blending 50-95 wt. % of a copolymer (A) of 10-75 wt. % of .alpha.-methyl styrene, 10-60 wt. % of methyl methacrylate, 5-35 wt. % of acrylonitrile and 0-20 wt. % of a monomer copolymerizable therewith; and 5-50 wt. % of a graft copolymer (B) comprising 50-85 wt. parts of a butadiene-based rubber polymer and 15-50 wt. parts of a vinyl monomer graft-polymerized onto the rubber polymer. The butadiene-based rubber polymer includes 50-98 wt. % of butadiene, 2-50 wt. % of an aromatic polycyclic vinyl monomer represented by a formula (I) below and 0-20 wt. % of a monomer copolymerizable therewith: ##STR1## wherein R denotes an optionally substituted biphenylyl or naphthyl group, and R.sub.1 denotes a hydrogen atom or a methyl group. The thermoplastic resin composition is provided with a good balance among heat-resistance, impact resistance, transparency and processability because the graft copolymer (B) using an aromatic polycyclic vinyl monomer shows a good impact resistance-modifying effect while retaining a relatively high refractive index and the copolymer (A) shows a good heat resistance and a relatively low refractive index.

Impact-resistant thermoplastic resin composition containing a grafted

A graft copolymer is formed by graft-polymerizing 10-95 wt. parts of a vinyl monomer onto 5-90 wt. parts of the rubber polymer which comprises 40-99 wt. % of butadiene and 1-60 wt. % of an aromatic polycyclic vinyl monomer represented by the following formula (I) or (II): ##STR1## wherein R denotes a hydrogen atom or a methyl group. The graft copolymer is characterized by the rubber polymer having a high refractive index as well as a low glass transition temperature due to the use of the aromatic polycyclic vinyl monomer. Accordingly, the graft copolymer per se may be used as a thermoplastic resin having good transparency and impact resistance at a low rubber polymer content and may also be added to a transparent thermoplastic resin inclusive of a vinyl chloride resin and a styrene-acrylonitrile copolymer resin to provide the thermoplastic resin with an improved impact resistance while retaining a good transparency.

Impact-resistant graft copolymer and thermoplastic resin composition

A powdery graft copolymer is obtained by a process characterized in that a graft copolymer latex obtained by graft-polymerizing hard-polymer-giving monomers to an elastic trunk polymer is mixed, after the coagulation of the latex or in the presence of a coagulant, with an organic liquid which is hardly soluble in water and does not dissolve but can wet the graft copolymer, in such a volume ratio that a dispersion wherein water forms a continuous dispersion medium phase and the volume ratio of the organic liquid to the graft polymer is 0.9 to 7.5 is formed, whereby the coagulated graft copolymer is impregnated with the organic liquid and dispersed in water, and then the dispersed copolymer particles are recovered from the water medium. According to this process, a graft copolymer having excellent powder characteristics such as fluidity and particle size distribution can be obtained by the use of a small quantity of an organic liquid.

Process for producing graft copolymer

A process of treating an exhaust gas containing NO.sub.x and SO.sub.2 comprising bringing the gas into contact with an absorbing solution containing iron chelate salt and potassium sulfite, cooling the solution to crystallize and separate absorption products of potassium imidodisulfonate, potassium dithionate and potassium sulfate, heating the separated products at 250.degree. to 400.degree. C. to decompose the potassium dithionate into potassium sulfate and sulfur dioxide, then decomposing the potassium imidodisulfonate into ammonia and simultaneously reducing the potassium sulfate into potassium polysulfide and potassium carbonate, and converting the potassium polysulfide into hydrogen sulfide, gaseous sulfur and potassium carbonate.

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Iwaki, Japan

Hiroshi Hagiwara