Sekisui Kaseihin Kogyo Kabushiki Kaisha

Tomohiko Ishida

Fumito Yamai

Toshiki Ikeda

Yoshinori Ikeda

Mutsuhiko Kajimura

Expandable ethylenically unsaturated polymer particles are produced by using in the process a suspension stabilizer comprising calcium carbonate particles having the surfaces thereof treated with resin acid. The method for the production of such expandable ethylenically unsaturated polymer particles from ethylenically unsaturated polymer particles includes suspending such particles in water and impregnating the particles with an organic expanding agent having a boiling point lower than the softening point of the polymer particles.

Process for the production of expandable ethylenically unsaturated

A process for preparing expandable styrene polymer particles by using calcium hydroxide as a suspending agent to prevent agglomeration of styrene polymer particles during impregnation with an expanding agent. The process comprises preparing expandable styrene polymer particles from styrene polymer particles in water, wherein the expanding agent (which does not dissolve styrene polymer particles or slightly swells the particles and has a boiling point lower than the softening point of the particles) is added in the presence of the suspending agent and the particles being impregnated thereby.

Process for the preparation of expandable styrene polymer particles

A process for preparing expandable styrene polymer particles by using magnesium oxide as a suspending agent to prevent agglomeration of styrene polymer particles during impregnation with an expanding agent. The process comprises preparing expandable styrene polymer particles from styrene polymer particles in water, wherein the expanding agent (which does not dissolve styrene polymer particles or slightly swells the particles, and has a boiling point lower than the softening point of the particles) is added in the presence of the suspending agent and the particles being impregnated thereby.

Process for preparing expandable styrene polymer particles

Expandable styrene polymer particle compositions containing an expanding agent which is volatilizable and does not dissolve or may slightly swell the styrene polymer particles and a small amount of sulfur containing compound having the general formula: ##EQU1## wherein, R.sub.1 and R.sub.2 are the same or different lower alkyl, aralkyl or aryl groups, R.sub.1 and R.sub.2 may be joined together to form an alkylene group, and

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Shiga, Japan

Tomohiko Ishida