Nissan Chemical Industries Limited

Nissan Maruzen Polyethylene Company

Yoshiho Matsuo

Ryoji Nishijima

Atsuhiko Yoshino

Kazumi Tsubaki

Hiroshi Morinaga

Takeshi Iwabuchi

Takai Kawashima

A process for producing a blow molding resin comprises pelletizing a high density polyethylene prepared by means of a highly active Ziegler catalyst, at a temperature of at least 230.degree. C. in the presence of air or oxygen so as not to change the average molecular weight and the molecular weight distribution.

Process for producing a blow molding resin

A process for producing a blow molding resin comprises pelletizing a high density polyethylene prepared by means of highly active Ziegler catalyst, characterized in that a small amount of a cross linking agent is added to the high density polyethylene and the pelletizing is conducted in an atmosphere containing a small amount of oxygen.

Ethylene or a mixture of ethylene and a small amount of another .alpha.-olefin or diene is polymerized in two successive steps under different hydrogen partial pressures by polymerizing 30 to 70 wt. % of the ethylene or ethylene mixture to be polymerized in the presence of hydrogen at a molar ratio of ethylene or ethylene mixture to hydrogen of 1:1-8 in the first step and polymerizing the residual ethylene or the ethylene mixture at a molar ratio of ethylene to hydrogen of 1:0-0.3 in the second step, in the presence of the specific catalyst system comprising an organoaluminum compound (C) and a specific solid catalytic component (B) obtained by reacting a titanium or vanadium halogen-containing compound with a reaction product (A) obtained by reacting a Grignard reagent with a hydropoly-siloxane having the formula ##EQU1## (R.sup.1 represents an alkyl, aryl, aralkyl, alkoxy, or aryloxy group as a monovalent organic group; a is 0,1 or 2; b is 1, 2 or 3; and a+b.ltoreq.3) or a silicon compound containing an organic group and hydroxyl group in the presence or absence of an aluminum-alkoxide, aluminum alkoxy-halide halide or a reaction product obtained by reacting the aluminum compound with water.

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Ichihara, Japan

Yoshiho Matsuo