Nippon Unicar Company Limited

Toshio Sakamoto

Takashi Furukawa

Koji Ishihara

Mamoru Yoshida

Kenichiro Kumai

Shigeru Gotoh

Tatsuhiko Inoue

An expandable resin composition comprising:

Expandable resin composition

An expandable resin composition comprising

A process for preparing an expandable resin composition comprising the following steps: (a) admixing, at a temperature in the range of about 120 to about 130 degrees C., the following components: (i) 100 parts by weight of a high pressure, low density homopolymer of ethylene; (ii) about 30 to about 200 parts by weight of a high density polyethylene having a melting point higher than the above mixing temperature; (iii) about 2 to about 50 parts by weight of polypropylene having a DSC melting point of not less than about 140 degrees C.; and (iv) about 0.1 to about 2 parts by weight of a silane coupling agent; and (b) admixing, at a temperature in the range of about 120 to about 130 degrees C., 100 parts by weight of the mixture produced in step (a) with 0.5 to 3 parts by weight of one or more chemical blowing agents having a decomposition temperature higher than the above mixing temperature.

A process for producing an expandable resin composition for a small diameter electric wire insulated with highly expanded cellular polyethylene which comprises (1) heat-kneading at a temperature higher than 135.degree. C. a mixture comprising: (i) a low density polyethylene having a density ranging from about 0.890 to 0.925 g/ml; (ii) a high density polyethylene having a melting point higher than 130.degree. C.; and (iii) a polyolefin wax having an average molecular weight ranging from about 1500 to 8000 and a melting point ranging from about 100.degree. C. to 160.degree. C.; and (2) heat kneading at a temperature ranging from 120.degree. C. to 130.degree. C. and at a preliminary expansion ratio lower than 5% the mixture of step (1) with a low temperature decomposable chemical blowing agent.

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Kanagawa, Japan

Toshio Sakamoto