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:
Jun. 03, 1986
Filed:
May. 06, 1985
Applicant:
Inventors:
Assignee:
Kureha Kagaku Kogyo Kabushiki Kaisha, Tokyo, JP;
Attorney:
Primary Examiner:
Int. Cl.
CPC ...
D03D / ;
U.S. Cl.
CPC ...
428224 ; 55DI / ; 428229 ; 428364 ; 428392 ; 428394 ; 428910 ;
Abstract
A vinylidene fluoride resin having an inherent viscosity of 0.8 to 1.4 dl/g in dimethylformamide is melt-extruded and cooled and solidified under draft-stretching to form a film having a birefringence of 25.times.10.sup.-3 or larger. The film is heat-treated at 80.degree.-120.degree. C. and split into a split yarn. The split yarn has a Young's modulus even higher than that of the polypropylene split yarn and, when provided with a surface charge above the glass transition temperature, retains the charge semi-permanently. The charged split yarn is particularly suitable for forming a gas filter.