Protective film of polarizer, polarizer and method for producing it, and liquid crystal display device

摘要

A protective film to a polarizer including a cellulose acylate and satisfying the following requirement (1) or (2):
(1): The surface of the film has a pH of from 3.0 to 4.5.(2): The surface of the film has a pH of more than 4.5 and at most 6.0, and the film has a moisture permeability of at least 2800 g/m2·day.

主权项

1. A protective film to a polarizer containing a cellulose acylate and an organic acid having an octanol/water partition coefficient of at least 3.0 and satisfying one of the following requirements:
(1): The surface of the film has a pH of from 3.0 to 4.5; or (2): The surface of the film has a pH of more than 4.5 and at most 6.0, and wherein the film has a moisture permeability of at least 2800 g/m2 ·day, the protective film to a polarizer comprising an organic acid represented by the following formula (1), wherein the ratio of the organic acid to the cellulose acylate is from 0.01 to 10% by mass:
X-L-(R1)n   Formula (1)wherein:
X represents an acid group wherein the acid dissociation constant is 5.5 or less; L represents a single bond, or a di- or more valent linking group; R1represents an alkyl group having from 6 to 30 carbon atoms, an alkenyl group having from 6 to 30 carbon atoms, an alkynyl group having from 6 to 30 carbon atoms, an aryl group having from 6 to 30 carbon atoms or a from 6 to 30 membered heterocyclic group, and each group may have a substituent; n represents 1 when L is a single bond, or represents the number expressed by:
(the valent number of L)−1when L is a di- or more valent linking group.