Nippon Steel Chemical Co., Ltd.

Koji Hirashima

Masanari Fujita

Toshio Fujita

Hideki Ono

Keiichi Hayashi

Toshihisa Fujitaka

Naoto Takeda

This invention relates to a method for removing unreacted monomers and other volatile matters from a polymer solution composition produced from a mixture containing an aromatic vinyl monomer, utilizes two or more flash devolatilizing vessels, and effects the removal by adjusting the solid content of the polymer solution composition at the outlet of the devolitilizer before the last-stage devolitilizer to a level in excess of 97%, adding 0.5-4 parts by weight of a foaming agent to the total polymer solution composition, passing the polymer solution composition through the last-stage devolitilizer while maintaining the pressure of the polymer solution at 10 kg/cm or more by means of a pressure controller and the temperature in the range 190-260&deg; C., introducing the polymer solution composition to a vapor-liquid separation vessel maintained at a vacuum of 20 Torr or less, and allowing the composition to foam.

Method for removing volatile matter from polymer solution composition

Rubber-modified styrene resins with excellent impact resistance are prepared by formulating a feed from a styrene-based monomer, or a mixture thereof with comonomers and high-viscosity rubber, an organic peroxide, and, if necessary, all inert organic solvent, preheating and continuously supplying the feed to one end of a plug flow type reactor equipped with an agitator, performing the preliminary polymerization to a conversion sufficiently high for the transformation of the rubber in the feed into particles while controlling the weight average particle diameter of the rubber particles to 0.8 to 5 .mu.m, withdrawing the prepolymerized feed from the other end of the reactor, and supplying it to a following plug flow type reactor for continuous enhancement of tile conversion.

Process for preparing rubber-modified styrene resins

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Kitakyushu, Japan

Koji Hirashima