Title:
RETARDATION FILM, PRODUCTION METHOD THEREFOR, AND CIRCULAR POLARIZER
Document Type and Number:
WIPO Patent Application WO/2021/085031
Kind Code:
A1
Abstract:
The invention provides a method for producing a retardation film having specific optical properties, said method including a first step of preparing a multilayer film comprising a resin layer (A) formed from a thermoplastic resin A having a positive intrinsic birefringence value and a resin layer (B) formed from a thermoplastic resin B having a negative intrinsic birefringence value and a second step of stretching the multilayer film two or more times at different stretching temperatures to obtain a retardation film, wherein the absolute value |TgA-TgB| of the difference between the glass transition temperature TgA of the thermoplastic resin A and the glass transition temperature TgB of the thermoplastic resin B is 5°C or greater.
Inventors:
OSATO KAZUHIRO (JP)
Application Number:
PCT/JP2020/037541
Publication Date:
May 06, 2021
Filing Date:
October 02, 2020
Export Citation:
Assignee:
ZEON CORP (JP)
International Classes:
G02B5/30; B29C55/14; B32B7/023
Domestic Patent References:
| WO2010035720A1 | 2010-04-01 | |||
| WO2018079746A1 | 2018-05-03 |
Foreign References:
| JP2009244609A | 2009-10-22 | |||
| JP2009251011A | 2009-10-29 | |||
| JP2009265302A | 2009-11-12 | |||
| JP2009237534A | 2009-10-15 | |||
| US20180149784A1 | 2018-05-31 |
Attorney, Agent or Firm:
SAKAI INTERNATIONAL PATENT OFFICE (JP)
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