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:
Dec. 09, 1997
Filed:
Jun. 06, 1995
Kaoru Iwata, Hachioji, JP;
Masanori Abe, Iwakuni, JP;
Utami Yonemura, Hino, JP;
Takeshi Sasaki, Hachioji, JP;
Teijin Limited, Osaka, JP;
Abstract
An acylated cellulose film having a high optical isotropy and uniformity is produced by dissolving an acylated cellulose in a solvent substantially free from water and including, as a principal component, 1,3-dioxolane in a ratio in weight of the acylated cellulose to the solvent of 10/250 to 10/15; spreading the acylated cellulose solution on a film-forming surface of a support; and drying, for example, initially drying the spread solution layer on film-forming surface so as to reduce the content of the residual solvent in the resultant film to 5 to 30% by weight; removing the resultant residual solvent-containing film from the film-forming surface; and finally drying the removed film, while allowing the film to shrink in the transversal direction thereof, at a drying temperature controlled continuously or intermittently to a level satisfying the relationship (I): (Tg'-50.degree. C.).ltoreq.T.ltoreq.(Tg'+20.degree. C.) (I), wherein T is the drying temperature (.degree.C.) and Tg' is a glass transition temperature (.degree.C.) of the solvent-containing film, the temperature Tg' varying in response to the solvent content in the film.