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:
Feb. 28, 1984
Filed:
Mar. 29, 1982
Tokio Okada, Tokyo, JP;
Shigezo Kojima, Tokyo, JP;
Haruhisa Tani, Tokyo, JP;
Kazuhiko Kurihara, Tokyo, JP;
Hirosi Yazawa, Kunitachi, JP;
Nippon Petrochemicals Co., Ltd, Tokyo, JP;
Polymer Processing Research Institute, Ltd., Tokyo, JP;
Abstract
A method and apparatus for stretching a thermoplastic polymer film in which the opposite selvages of the film are gripped by gripping means and are stretched transversely during heating by moving the selvages along two divergent arcuate paths lying in the same plane and extending over a predetermined circumferential range from a quater to a half of the full circumference of the circle containing the arcuate paths. In order to avoid drawbacks in the existing equipment such as irregular molecular orientation in and rupture of the film, the longitudinal travel of the film while being stretched is controlled by controlling means so that the central web portion is advanced by substantially the same distance as the gripped film selvages, whereby the amound of longitudinal movement of the film is held always constant throughout the width of the film.