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:
May. 08, 2007
Filed:
Sep. 23, 2002
Tetsuya Tsunekawa, Otsu, JP;
Takuji Higashioji, Kyoto, JP;
Kenji Tsunashima, Kyoto, JP;
Toray Industries, Inc., Tokyo, JP;
Abstract
The object of the present invention is to provide a method for producing a polyester film excellent in rigidity, toughness, dimensional stability, electric properties, etc. and less in thickness fluctuation and surface defects, hence very suitable as a film for various industrial materials such as magnetic recording media, capacitors, heat transfer ribbons and thermal mimeographic stencil paper. The first method of the present invention is a method for producing a polyester film, in which a film made of a resin mainly composed of a polyester is simultaneously biaxially stretched by a simultaneously biaxially stretching tenter oven, comprising the step of effecting small-ratio stretching at an area stretching ratio of 1.0005 to 3.0 times three times or more, to achieve a total area stretching ratio of 25 to 150 times, and the second method of the present invention is a method for producing a polyester film, in which a film made of a resin mainly composed of a polyester is stretched using a simultaneously biaxially stretching tenter oven, comprising the step of effecting a series of operation consisting of stretching and subsequent relaxation twice to less than 10000 times, to achieve a total area stretching ratio of 25 to 150 times.