Polyvinyl alcohol polymer film

• Main Authors: KAZETO, OSAMU, DAIFUKU, KOICHI, TOYOSHIMA, YUTAKA, MINAKUCHI, HIROYUKI, SASAI, KOUJI, KATSUNO, RYOJI
• Format: Patent
• Language: Chinese; English
• Published: 11.11.2016
• Subjects: AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F,C08G; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING; CHEMISTRY; COMPOSITIONS BASED THEREON; GENERAL PROCESSES OF COMPOUNDING; INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS; METALLURGY; OPTICAL ELEMENTS, SYSTEMS, OR APPARATUS; OPTICS; ORGANIC MACROMOLECULAR COMPOUNDS; PERFORMING OPERATIONS; PHYSICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDEDFOR; SHAPING OR JOINING OF PLASTICS; THEIR PREPARATION OR CHEMICAL WORKING-UP; TRANSPORTING; WORKING OF PLASTICS; WORKING OF SUBSTANCES IN A PLASTIC STATE, IN GENERAL; WORKING-UP

[Problem] To provide a PVA-based polymer film from which a polarizing film or polarizing plate that have few defects can be produced in high yield, and to provide a PVA-based polymer film roll in which the surface properties fluctuate little throughout the whole film ranging from the initially wound portion to the finally wound portion thereof and from which a polarizing film or polarizing plate of stable quality can be produced. [Solution] A PVA-based polymer film in which the number of defects that are recesses in the film surface and that each have an area of 400 µm2 or larger and a depth of 0.3 µm or more is 0.25 per m2 or less; and a film roll obtained by continuously winding up a long PVA-based polymer film, wherein with respect to defects that are recesses in the film surface and that each have an area of 400 µm2 or larger and a depth of 0.3 µm or more, the ratio of the number of the defects in the finally wound portion of the PVA-based polymer film to the number of the defects in the initially wound p