Nippon Oil Company

Nippon Petrochemicals Company, Limited

Polymer Processing Research Institute Ltd.

Kazutosi Nomiyama

Kazuo Matsuura

Nobuyuki Kuroda

Kazuhiko Kurihara

Hiroshi Yazawa

Yoshio Tajima

Seizo Kobayashi

Yoshimu Iwanami

Sumio Yoshida

Yoshinori Nishikitani

Yoshiyuki Shimo

The present invention provides a prepreg obtained by stretching a material including, as a main component, an ultra-high-molecular-weight polyethylene having an intrinsic viscosity of 5-50 dl/g as measured at 135.degree. C. in decalin, to a total draw ratio of at least 20, subjecting the resulting stretched polyethylene material to a splitting treatment, and impregnating the resulting material with a thermosetting resin. The split stretched polyethylene material has improved adhesion to the impregnant resin and can be used as a good base material for prepreg.

Prepreg of ultra-high-molecular-weight polyethylene

The present invention provides a prepreg obtained by stretching a material including, as a main component, an ultra-high-molecular-weight polyethylene having an intrinsic viscosity of 5-50 dl/g as measured at 135.degree. C. in decalin, to a total draw ratio of at least 20, subjecting the resulting stretched polyethylene material to a splitting treatment, and impregnating the resulting material with a thermosetting resin, and a process for producing said prepreg. The split stretched polyethylene material has improved adhesion to the impregnant resin and can be used as a good base material for prepreg.

Process for producing prepreg

A process for preparing an ethylene polymer by a two-stage polymerization of ethylene or ethylene and an .alpha.-olefin in an inert hydrocarbon at 50.degree.-100.degree. C. using a coordination polymerization catalyst containing a solid component and an organoaluminum compound, said solid component containing a transition metal compound, which process comprises:

Process for preparing ethylene polymers

Disclosed is polyethylene composition having excellent environmental stress cracking resistance (ESCR) and giving molded articles with good surface properties. This composition comprises a blend of two specific types of polyethylene selected with due consideration for their molecular weight distribution in addition to their molecular weights, so that it has excellent melt tension, ESCR and moldability. Accordingly, it can suitably be used in blow molding and extrusion molding to produce molded articles with no shark skin, as well as vessels of very large size. This composition is formed by blending (A) polyethylene obtained according to a two-step polymerization process using a Ziegler catalyst containing magnesium and titanium, and (B) high-molecular-weight polyethylene obtained with the aid of a chromium-containing catalyst, in a specified proportion.

Polyethylene composition

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Akishima, Japan

Kazutosi Nomiyama