Kanegafuchi Kagaku Kogyo Kabushiki Kaisha

Toshiaki Sugita

Kiyoshi Mori

Masao Nakagawa

Kazuo Saito

Yoshiyuki Hashiguchi

Hideyuki Arakawa

Yuichi Ueda

Hiromitsu Tachibana

Masakichi Kishi

Toshiaki Sasaki

A method for manufacturing expandable styrene type polymer particles is disclosed, which comprises the steps of adding a styrene type monomer to styrene type polymer seed particles suspended in an aqueous dispersing medium, continuously or intermittently to be polymerized while being absorbed thereby, and impregnating the resulting polymer particles with an easily volatile blowing agent to obtain expandable styrene type polymer particles, the improvement wherein styrene type polymer particles whose weight-average molecular weight (Mw.sub.1) is not more than 2/3 of the weight-average molecular weight (Mw.sub.2) of the resulting polymer particles are used as said styrene type polymer particles. The present invention provides expandable styrene type polymer particles excellent in moldability and foamed articles high in strength and fine in external appearance.

Method for manufacturing expandable styrene type polymer particles

The present invention provides a method for producing expandable thermoplastic polymer particles which comprises conducting polymerization by adding a polymerizable monomer either continuously or intermittently to thermoplastic polymer particles having a uniform particle size suspended in water, the improvement wherein an amide compound is added when the added amount of the polymerizable monomer is not more than one half of the total amount to be added in the course of polymerization and resulting polymer particles are impregnated with an easily volatile blowing agent after completion of addition of the amide compound and the polymerizable monomer. According to the present invention, expandable thermoplastic particles which are capable of giving cells, fine and uniform in size, are obtainable even by expanding immediately after production without any aging period.

Method for producing expandable thermoplastic polymer particles

A process for preparing .alpha.-methylstyrene/acrylonitrile copolymer by suspension or bulk polymerization of .alpha.-methylstyrene and acrylonitrile with at least one member selected from the group consisting of styrene, chlorostyrene, para-methylstyrene, t-butylstyrene, acrylic ester and methacrylic ester in the presence of a difunctional organic peroxide having a 10 hour half-life temperature of 60.degree. to 120.degree. C. and capable of producing a t-butyl radical, at a polymerization temperature of 80.degree. to 135.degree. C. The process produces the copolymers having excellent transparency, heat resistance and strength in a high conversion in a short time.

Process for preparing copolymer

A method of suspension polymerizing in an aqueous medium vinyl chloride or a mixture of 50% or more vinyl chloride and remainder other monomers copolymerizable therewith in the presence of an oil soluble initiator, a suspension stabilizer and 0.005 to 50 ppm of nitrite, and 10 to 1000 ppm of water soluble metallic salt, the parts being based on the amount of aqueous medium.

Growing community of inventors

Akashi, Japan

Toshiaki Sugita