# US 10,501,593 B2 · Dope composition, polarizing plate protective film, polarizing plate protective film manufacturing method, polarizing plate, and liquid crystal display device

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- Number: US 10,501,593 B2
- Document ID: US10501593B2
- Status: Granted
- Kind: B2
- Application number: 15/188,367
- Filed: 2016-06-21
- Published: 2016-10-13
- Granted: 2019-12-10
- Earliest claimed: 2013-12-27
- Assignees: FUJIFILM Corporation
- Applicants: FUJIFILM Corporation
- Inventors: Shusuke Arita; Yutaka Nozoe; Katsumi Sasata; Hajime Nakayama
- Web page: https://patentgrep.com/patent/US10501593B2

## CPC

- C08J 5/18: Manufacture of films or sheets
- B29C 41/28: by depositing flowable material on an endless belt
- B29D 11/00644: {polarizing}
- C08F 220/14: Methyl esters {, e.g. methyl (meth)acrylate}
- C08L 33/12: Homopolymers or copolymers of methyl methacrylate
- G02B 1/14: Protective coatings, e.g. hard coatings
- G02B 5/3025: {Polarisers, i.e. arrangements capable of producing a definite output polarisation state from an unpolarised input state (G02B5/3008, G02B5/3016 take precedence)}
- G02F 1/133528: {Polarisers}
- B29K 2033/12: {Polymers of methacrylic acid esters, e.g. PMMA, i.e. polymethylmethacrylate}
- C08J 2333/12: Homopolymers or copolymers of methyl methacrylate
- C08K 5/13: Phenols; Phenolates
- C08K 5/1345: {Carboxylic esters of phenolcarboxylic acids}
- C08K 5/34924: {containing cyanurate groups; Tautomers thereof}
- C08L 2203/206: use in coating or encapsulating of electronic parts
- G02B 5/3033: {in the form of a thin sheet or foil, e.g. Polaroid}
- C08J: WORKING-UP; GENERAL PROCESSES OF COMPOUNDING; AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F, C08G or C08H (working, e.g. shaping, of plastics B29)
- B29C: SHAPING OR JOINING OF PLASTICS; SHAPING OF MATERIAL IN A PLASTIC STATE, NOT OTHERWISE PROVIDED FOR; AFTER-TREATMENT OF THE SHAPED PRODUCTS, e.g. REPAIRING (making preforms B29B11/00; making laminated products by combining previously unconnected layers which become one product whose layers will remain together B32B37/00 - B32B41/00)
- B29D: PRODUCING PARTICULAR ARTICLES FROM PLASTICS OR FROM SUBSTANCES IN A PLASTIC STATE (making granules B29B9/00; making preforms B29B11/00)
- C08F: MACROMOLECULAR COMPOUNDS OBTAINED BY REACTIONS ONLY INVOLVING CARBON-TO-CARBON UNSATURATED BONDS
- C08L: COMPOSITIONS OF MACROMOLECULAR COMPOUNDS (compositions based on polymerisable monomers C08F, C08G; artificial filaments or fibres D01F; textile treating compositions D06)
- G02B: OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
- G02F: OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
- B29K: INDEXING SCHEME ASSOCIATED WITH SUBCLASSES B29B, B29C OR B29D, RELATING TO MOULDING MATERIALS OR TO MATERIALS FOR {MOULDS, } REINFORCEMENTS, FILLERS OR PREFORMED PARTS, e.g. INSERTS
- C08K: Use of inorganic or non-macromolecular organic substances as compounding ingredients (paints, inks, varnishes, dyes, polishes, adhesives C09)

## 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.

## Claims

### Claim 1

A dope composition, containing:
an acrylic resin having a weight average molecular weight of greater than or equal to 250,000; and
a drying additive having a weight average molecular weight of less than 50,000,
wherein the acrylic resin is formed only of a methyl methacrylate unit a,
wherein the drying additive contains a phenol-based compound denoted by General Formula (1) described below; and
in General Formula (1), R1 and R4 each independently represent a hydrogen atom, a methyl group, or a t-butyl group, R2 and R3 each independently represent a hydrogen atom or a methyl group; X represents a divalent organic group formed of a combination of two or more groups selected from the group consisting of —CH2—, —CO—, —O—, and —NR5—, R5 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,
wherein the drying 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:
in General Formula (2), R6 represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms, and R7 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), R8 represents a hydrogen atom or a methyl group, and R9 represents a hydrogen atom or an alkyl group having 1 to 20 carbon atoms, and
wherein the drying additive contains a novolak resin having a structure unit denoted by General Formula (5) described below:
in General Formula (5), R10 represents a hydroxyl group or an alkoxy group having 1 to 2 carbon atoms, and R11 represents a hydrogen atom or an alkyl group having 1 to 8 carbon atoms.

### Claim 2 (depends on 1)

The dope composition according to claim 1,
wherein the drying 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.

### Claim 3 (depends on 1)

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

### Claim 4 (depends on 3)

The polarizing plate protective film according to claim 3,
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.

### Claim 5 (depends on 3)

The polarizing plate protective film according to claim 3,
wherein moisture permeability in terms of a film thickness of 40 μm is less than or equal to 70 g/m2/day.

### Claim 6 (depends on 1)

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.

### Claim 7 (depends on 3)

A polarizing plate, comprising:
the polarizing plate protective film according to claim 3.

### Claim 8 (depends on 7)

A liquid crystal display device, comprising:
the polarizing plate according to claim 7.