The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Nov. 06, 1990
Filed:
Apr. 29, 1988
Hisashi Kojoh, Yatsushiro, JP;
Naoya Yamaguchi, Yatsushiro, JP;
Kazuhiro Tomoda, Hita, JP;
Tomoji Mizutani, Yatsushiro, JP;
Yukio Wakuda, Yatsushiro, JP;
Kohjin Co., Ltd., Tokyo, JP;
Abstract
A process for producing a porous resin film containing a polyolefin resin as a main component, comprising meltinig a mixture of (A) 100 parts by weight of a polyolefin resin, (B) 0 to 50 parts by weight of a polyester-polyether type thermoplastic elastomer, and (C) a thermoplastic polyester resin having an instrinsic viscosity of not more than 0.5, the amount of the component (C) being from 25 to 90 part by weight per 100 parts of the total amount of the component (A) and the component (B), by heating the mixture at a temperature of not less than the melting temperature of the component (C); kneading the mixture at a shear rate of not less than 200/sec. while cooling the mixture to a temperature of not more than the crystallization temperature of the component (C) and not less than the melting temperature of the component (A); subjecting the mixture to film-forming at a temperature of less than the melting temperature of the component (C) and not less than the melting temperature of the component (A) and cooling the resultant rapidly to obtain a non-stretched film; and stretching the non-stretched film in at least one direction. The porous film obtained by the process has an excellent water proof and an excellent water vapor permeability.