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. 20, 1979
Filed:
Jun. 10, 1977
Keiichi Uno, Otsu, JP;
Hikoichi Nagano, Otsu, JP;
Tsuyoshi Hongo, Otsu, JP;
Takahito Miyagawa, Otsu, JP;
Koichi Matsunami, Otsu, JP;
Toyo Boseki Kabushiki Kaisha, Osaka, JP;
Abstract
A shaped article having a refractive index of not less than 1.625 at least in one direction and possessing excellent physical properties and various uses, which can be prepared by stretching a molded product, which is made of a polymeric material comprising at least 80 mol% of the repeating units of the formula: ##STR1## and having an intrinsic viscosity of not less than 0.25 dl/g when measured in a mixture of phenol and sym.-tetrachloroethane in a weight ratio of 6 : 4 at 30.degree. C. and has a refractive index of not more than 1.610 at least in one direction, at a temperature of 120.degree. to 230.degree. C. with a stretch ratio of 2 to 20 in the same direction as the refractive index is measured, or by melt extruding the polymeric material at a temperature higher than 230.degree. C. and not higher than 360.degree. C. while or immediately followed by stretching with a deformation speed of not less than 20 times the speed of the melt extrusion.