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:
Oct. 23, 1990
Filed:
Dec. 07, 1988
Toray Industries, Inc., Tokyo, JP;
Abstract
Polyester films with a good slitting property and good slipping property contain, in first and second embodiments, at least 0.005% by weight of calcium carbonate particles. The particle size S.sub.c of the polyester crystals, crystal face orientation index X.sub.i and the difference .DELTA.n between the refractive indices in the machine direction and in the transverse direction of the polyester film have a specific relationship, or the internal haze H, face orientation coefficient f.sub.n or the difference .DELTA.n between the refractive indices in the machine direction and in the transverse direction have a specific relationship. By satisfying the specific relationship, a good slitting property and good slipping property are obtained. A third embodiment provides a polyester film containing at least 0.005% by weight of calcium carbonate particles, which has a specific center line average roughness Ra, face orientation coefficient f.sub.n, the difference .DELTA.n between the refractive indices in the machine direction and in the transverse direction, and F-5 value in the transverse direction. By these characteristics, a good slitting property, good slipping property and good shaving property are obtained.