Usm Corporation

Nippon Steel Chemical Co., Ltd.

Eiki Orihara

Akira Aiba

Kiyoshi Fukushima

Akifumi Hayakawa

Mould assembly for foam moulding of plastic materials, which comprises stationary and movable dies and an auxiliary die plate device between the stationary and movable dies. A gas passage is formed for introducing pressurized inert gas into the mould cavity. The auxiliary die device comprises separated inner and outer auxiliary dies both being spring biased toward the stationary die. O-ring seals are disposed between the opposite surfaces of the outer auxiliary die and the stationary and movable dies.

Mould assembly for foam moulding of plastic materials

This invention relates to an improved injection foam molding method in which a foamable mixture of molten synthetic polymer resin and a chemical blowing agent in unfoamed condition is injected into a gas-pressurized expandable mold having a mold section movable for expanding the mold cavity to a position in which the surface of that section is in registry to the surface of another mold section, in which process the mold is filled under conditions resisting foaming of the material prior to filling of the mold and a novel controlled time sequence effective to form a fine mold crease line is employed in releasing the gas pressure and expanding the mold to allow foaming of the mixture into conformity with the mold surface.

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Tokyo, Japan

Eiki Orihara