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:
Apr. 17, 1984
Filed:
Apr. 21, 1982
Idemitsu Petrochemical Co., Ltd., Tokyo, JP;
Abstract
A method of producing a biaxially oriented sheet or film, wherein molten resin is simultaneously, biaxially oriented in a direction of extruding the molten resin and in a direction perpendicular thereto, and an apparatus therefor, are disclosed. In the method of producing a biaxially oriented sheet or film, the molten resin is extruded into a tubular form in the horizontal direction, once cooled, thereafter, in heating the tubular resin prior to the biaxial orientation, the tubular resin is uniformly heated with the heating applied on the vertically lower side and the heating applied on the vertically upper side of the tubular resin being controlled separately of each other so as to prevent the ununiformity of the heating of the tubular resin in the circumferential direction thereof due to the elevation in heat caused by a thermal convection phenomenon, and then, the tubular resin is biaxially oriented.