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. 02, 2024
Filed:
Jun. 20, 2019
Mitsui Chemicals, Inc., Tokyo, JP;
Mitsui Chemicals, Inc., Tokyo, JP;
Abstract
The purpose of the present invention is to provide: a film having high thermal stability, high bending strength (tensile elongation), small retardation in the thickness direction, a low coefficient of thermal expansion, and high transparency; and a polyamic acid or varnish for obtaining the film. The film satisfies all of requirements (i)-(vi) below. (i) The average value of the coefficient of thermal expansion in the range of 100-200° C. is 35 ppm/K or less. (ii) The absolute value of the retardation in the thickness direction is 200 nm or less per 10 μm of thickness. (iii) The glass transition temperature is 340° C. or higher. (iv) The total light transmittance is at least 85%. (v) The b* value in the L*a*b* color system is 5 or less. (vi) The tensile elongation is at least 10%.