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1. (WO2018199139) POLYVINYL ALCOHOL FILM, POLARIZING FILM AND POLARIZING PLATE, AND POLYVINYL ALCOHOL FILM PRODUCTION METHOD

Pub. No.:    WO/2018/199139    International Application No.:    PCT/JP2018/016752
Publication Date: Fri Nov 02 00:59:59 CET 2018 International Filing Date: Thu Apr 26 01:59:59 CEST 2018
IPC: G02B 5/30
B29C 55/08
C08J 5/18
B29K 29/00
B29L 7/00
B29L 11/00
Applicants: THE NIPPON SYNTHETIC CHEMICAL INDUSTRY CO., LTD.
日本合成化学工業株式会社
Inventors: SHIMIZU Toshihiro
清水 俊宏
KITAMURA Shuichi
北村 秀一
TERAMOTO Yuuichi
寺本 裕一
Title: POLYVINYL ALCOHOL FILM, POLARIZING FILM AND POLARIZING PLATE, AND POLYVINYL ALCOHOL FILM PRODUCTION METHOD
Abstract:
A polyvinyl alcohol film which has an excellent balance of swelling properties and stretching properties during polarizing film manufacture, does not result in rupture during thin polarizing film production, and enables obtaining a polarizing film that exhibits high polarization performance and has few color irregularities, a polarizing film and polarizing plate using said polyvinyl alcohol film, and a polyvinyl alcohol film production method are provided. This polyvinyl alcohol film is elongate and 5-60 μm thick, and is characterized by satisfying all of the expressions (A) to (C) below when ΔnMDA is defined as the birefringence in the length direction (MD) of a first surface, ΔnMDB is defined as the birefringence in the length direction (MD) of a second surface, and ΔnMDC is defined as the birefringence of the center portion in the thickness direction. (A)... 1.0 ≤ ΔnMDA / ΔnMDB ≤ 1.5 (B)... ΔnMDB - ΔnMDC ≥ 0.2×10-3 (C)...ΔnMDA≥3.0×10-3