Sanwa Kako Company Limited

Yoshio Miyano

Tomoyoshi Shibata

Nobuyoshi Kotani

Naruyuki Ida

Kazuyoshi Fujimura

Katsuya Matsumoto

A method is disclosed that makes a open cell cellular body of polyethylene resin material in non-crosslinked structure, which has a maximum degree of cell interconnection, is good in recyclability and excellent in heat resistance or resistance to heat distortion. The method includes the steps of adding 4,4&prime;-oxy bis (benzene sulfonyl hydrazide) to a polyethylene resin material to form a foamable composition and shaping the foamable composition of polyethylene resin material, heating the shaped foamable composition of polyethylene resin material to be foamed under an atmospheric pressure to form a cellular body thereof with cells therein, and mechanically deforming the cellular body of polyethylene resin material to cause the cells therein to be interconnected, thereby producing the open cell cellular body desired. The produced continuous cellular body is rendered heat resistant by irradiating the same or the formed cellular body with a beam of electrons.

Method of making polyethylene resinous open cell cellular bodies

An open-cell foam of a cross-linked polyolefin possessing uniform physical properties, a high degree of expansion, and a high open-cell ratio can be produced with high operational efficiency and high material utilization by a method which includes thermally shaping under pressure a foamable and cross-linkable polyolefin composition capable of being heated with a microwave, then heating the composition by irradiation with a microwave thereby inducing partial decomposition of a cross-linking agent and a foaming agent contained in the composition, subsequently externally heating under normal pressure the resultant intermediate partially foamed product thereby effecting decomposition of the remainders of the cross-linking agent and foaming agent, and thereafter subjecting the resultant foam to mechanical deformation thereby establishing intercommunication among the cells. The surface of the foamable and cross-linkable polyolefin composition may be heated prior to the heating with a microwave to effect partial cross-linking of the surface part of the composition.

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Kyoto, Japan

Yoshio Miyano