Dope composition, polarizing plate protective film, polarizing plate protective film manufacturing method, polarizing plate, and liquid crystal display device

Patent metadata

Field	Value
Publication number	US-2016297939-A1
Application number	US-201615188367-A
Country	US
Kind code	A1
Filing date	Jun 21, 2016
Priority date	Dec 27, 2013
Publication date	Oct 13, 2016
Grant date	—

Abstract

A dope composition containing an acrylic resin having a weight average molecular weight of greater than or equal to 250,000; and an additive having a weight average molecular weight of less than 50,000, in which the acrylic resin includes a methyl methacrylate unit (a), and a mass fraction of an alkyl (meth)acrylate unit (b) other than methyl methacrylate is less than 5 mass %, has excellent manufacturing aptitude from the viewpoint of having a high drying speed and large breaking elongation at a time point of forming an un-stretched film, and enabling a crack at the time of being stretched to be suppressed, has a low haze value and an excellent surface shape at the time of preparing a polarizing plate protective film, and has excellent heat resistance; a polarizing plate protective film; a polarizing plate protective film manufacturing method; a polarizing plate; and a liquid crystal display device.

First claim

What is claimed is:

1 . A dope composition, containing:
an acrylic resin having a weight average molecular weight of greater than or equal to 250,000; and an additive having a weight average molecular weight of less than 50,000, wherein the acrylic resin includes a methyl methacrylate unit a, and a mass fraction of an alkyl (meth)acrylate unit b other than methyl methacrylate is less than 5 mass %.

2 . The dope composition according to claim 1 ,
wherein the acrylic resin is formed of an alkyl (meth)acrylate unit, and a mass fraction of the methyl methacrylate unit a is greater than or equal to 95 mass %.

3 . The dope composition according to claim 1 ,
wherein the acrylic resin is formed of the methyl methacrylate unit a.

4 . The dope composition according to claim 1 ,
wherein the additive is contained in the amount of greater than or equal to 5 parts by mass with respect to 100 parts by mass of the acrylic resin.

5 . The dope composition according to claim 1 ,
wherein the additive contains a phenol-based compound denoted by General Formula (1) described below; and

in General Formula (1), R 1 and R 4 each independently represent a hydrogen atom, a methyl group, or a t-butyl group, R 2 and R 3 each independently represent a hydrogen atom or a methyl group; X represents a single bond, or a divalent organic group selected from —CH 2 —, —CO—, —O—, and —NR 5 — or a divalent organic group formed of a combination of two or more groups selected from the group consisting of —CH 2 —, —CO—, —O—, and —NR 5 —, R 5 represents a hydrogen atom or an alkyl group; Y represents a hydrogen atom, a carbon atom, a sulfur atom, an aromatic hydrocarbon group, or a hetero ring; and n represents an integer of 1 to 4.

6 . The dope composition according to claim 1 ,
wherein the additive contains a styrene-based copolymer having a structure unit denoted by General Formula (2) described below and a structure unit denoted by General Formula (3) or (4) described below; and

in General Formula (2), R 6 represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R 7 represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms, and an alkyl carbonyl oxy group having 1 to 4 carbon atoms; and in General Formula (3), R 8 represents a hydrogen atom or a methyl group, and R 9 represents a hydrogen atom or an alkyl group having 1 to 20 carbon atoms.

7 . The dope composition according to claim 1 ,
wherein the additive contains a novolak resin having a structure unit denoted by General Formula (5) described below; and

in General Formula (5), R 10 represents a hydroxyl group or an alkoxy group having 1 to 12 carbon atoms, and R 11 represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms.

8 . A polarizing plate protective film, comprising:
a polymer film obtained by performing film formation with respect to the dope composition according to claim 1 .

9 . The polarizing plate protective film according to claim 8 ,
wherein diffusion coefficients De and Dn defined by Expression (1) described below satisfy conditions of Expression (2) described below; and
De=Pe/Se, Dn=Pn/Sn   Expression (1)

De/Dn> 1  Expression (2)

in Expressions (1) and (2), Pe represents moisture permeability of the polarizing plate protective film, Se represents an equilibrium moisture content of the polarizing plate protective film at a temperature of 25° C. and relative humidity of 80%, Pn represents moisture permeability of an additive-free film which has the same configuration as that of the polarizing plate protective film except that the additive is not contained, and Se represents an equilibrium moisture content of the additive-free film at a temperature of 25° C. and relative humidity of 80%; and here, the moisture permeability is a value obtained by converting a value after being aged at a temperature of 40° C. and relative humidity of 90% for 24 hours into a film thickness of 40 μm using a method of JIS Z-0208.

10 . The polarizing plate protective film according to claim 8 ,
wherein moisture permeability in terms of a film thickness of 40 μm is less than or equal to 70 g/m 2 /day.

11 . A polarizing plate protective film manufacturing method, comprising:
a dissolving step of dissolving the dope composition according to claim 1 in a solvent and preparing a dope; a casting step of casting the dope onto a metal support and forming a casting film; and a peeling step of drying the casting film, peeling off the casting film from the metal support, and then, obtaining a polymer film.

12 . A polarizing plate, comprising:
the polarizing plate protective film according to claim 8 .

13 . A liquid crystal display device, comprising:
the polarizing plate according to claim 12 .

Assignees

• Fujifilm Corp

Inventors

• Arita Shusuke
• Nozoe Yutaka
• Sasata Katsumi
• Nakayama Hajime

Classifications

• C08J2333/12

  Homopolymers or copolymers of methyl methacrylate · CPC title

• C08J5/18 Primary

  Manufacture of films or sheets · CPC title

• G02B1/14

  Protective coatings, e.g. hard coatings · CPC title

• B29C41/28

  by depositing flowable material on an endless belt · CPC title

• C08L33/12

  Homopolymers or copolymers of methyl methacrylate · CPC title