WO2017057254A1

WO2017057254A1 - Laminate, polarizing plate, and image display device

Info

Publication number: WO2017057254A1
Application number: PCT/JP2016/078231
Authority: WO
Inventors: 寛野副; 佑起中沢; 一洋雨宮; 正人名倉
Original assignee: 富士フイルム株式会社
Priority date: 2015-09-30
Filing date: 2016-09-26
Publication date: 2017-04-06

Abstract

Provided are a laminate, a polarizing plate using this laminate, and an image display device using this polarizing plate. The laminate has a cellulose ester resin layer and an adhesive polymer layer provided directly upon the cellulose ester resin layer. An adhesive polymer constituting the adhesive polymer layer has a repeating unit [a] and a repeating unit [b]. [a]: A repeating unit derived from a specific compound and having a solubility parameter δt calculated by the Hoy method of 13.5-19.5. [b]: A repeating unit derived from a specific compound and having a solubility parameter δt calculated by the Hoy method of 20.0-26.0.

Description

Laminated body, polarizing plate, and image display device

The present invention relates to a laminate, a polarizing plate using the laminate, and an image display device.

Image display devices represented by electroluminescence displays (ELDs) and liquid crystal display devices (LCDs) are increasingly required to be thin. In addition, the usage environment of image display devices has been diversified, including outdoor applications, and image display devices have the ability to stably maintain good image quality even in harsh environments (high durability). Is now required.
The decrease in image quality in the image display apparatus is partly caused by moisture entering the polarizing plate and degrading the polarizer. The polarizer is protected by laminating a protective film (optical film) on the surface, but the protective film is also required to be thin. When the protective film is thinned, moisture is more likely to come into contact with the polarizer, and the image quality is likely to deteriorate. In addition, such a decrease in image quality becomes more apparent when used in harsh environments such as outdoor applications.

As the protective film, cellulose resins and acrylic resins are widely used from the viewpoint of versatility and processability. Due to the necessity of further improving the durability, the optical film is being modified (for example, Patent Documents 1 to 5).

International Publication No. 2009/047924 JP 2012-172062 A JP 2006-83225 A JP 2013-101281 A JP-A-9-197128

As a result of repeated investigations from the viewpoint of suppressing the deterioration of the polarizer, the inventors of the present invention have a structure of conventional protective films including the films described in the above patent documents. It has become clear that moisture penetration cannot be sufficiently prevented and it is difficult to suppress the deterioration of the polarizer to a target level.
The present invention is a laminate provided with a cellulose ester resin layer, which is excellent in adhesion between layers, can effectively suppress moisture transmission even when thinned, and when used as a protective film for a polarizer It is an object of the present invention to provide a laminate capable of effectively suppressing deterioration of a polarizer, a polarizing plate using the laminated body, and an image display device using the polarizing plate.

As a result of intensive studies in view of the above problems, the present inventors have found that a polymer having a repeating unit having a specific structure in which the solubility parameter is within a specific range, and a repeating unit having a specific structure in which the solubility parameter is different from the repeating unit. The laminate in which the layer is directly provided on the cellulose ester resin layer has excellent adhesion between the polymer layer and the cellulose ester resin layer, and has a low moisture permeability and is used as a protective film for a polarizer. It has been found that deterioration of the polarizer can be effectively suppressed even under wet conditions.
The present invention has been further studied based on these findings and has been completed.

The above-described problems of the present invention have been solved by the following means.
[1]
It has a cellulose ester resin layer and an adhesive polymer layer provided directly on the cellulose ester resin layer, and the adhesive polymer constituting the adhesive polymer layer is at least one repeating unit of the following [a]: The laminated body which has at least 1 sort (s) of the repeating unit of following [b].
[A]:
A repeating unit derived from a (meth) acrylic ester compound, an olefin compound, a vinylidene compound or a cyclic olefin compound and having a solubility parameter δt calculated by the Hoy method of 13.5 to 19.5.
[B]:
(Meth) acrylic acid ester compounds, (meth) acrylic acid compounds, (meth) acrylamide compounds, vinyl acetate compounds, vinyl ketone compounds, maleic anhydride compounds or repeating units derived from styrene compounds or ethylenically unsaturated other than these repeating units A repeating unit derived from a compound having a bond and having a solubility parameter δt calculated by the Hoy method of 20.0 to 26.0.
[2]
The laminate according to [1], wherein the adhesive polymer has a repeating unit represented by the following general formula 1 as the repeating unit of [b].
General formula 1:

In general formula 1,
R ¹ represents a hydrogen atom or an alkyl group.
R ² and R ³ represent a hydrogen atom, an alkyl group, an aryl group or an alkoxycarbonyl group.
L is a single bond, or a divalent linking group selected from an alkylene group, an arylene group, —C (═O) —, —O— and —N (R ⁴ ) —, or 2 of these linking groups. A divalent linking group formed by combining more than one species is shown.
R ⁴ represents a hydrogen atom or an alkyl group.
[3]
The laminate according to [1] or [2], wherein the adhesive polymer has a repeating unit represented by the following general formula 2 as the repeating unit of [a].
General formula 2:

In general formula 2,
R ⁵ represents a hydrogen atom or an alkyl group.
R ⁶ and R ⁷ represent a hydrogen atom, an alkyl group, an aryl group or an alkoxycarbonyl group.
R ⁸ represents an alkyl group having 1 to 20 carbon atoms or a cycloalkyl group having 3 to 10 carbon atoms.
[4]
Any one of [1] to [3], wherein the molar amount of the repeating unit [b] in the total molar amount of the monomer component constituting the adhesive polymer is 5 mol% or more and 90 mol% or less. Laminated body.
[5]
The laminate according to any one of [1] to [4], wherein the adhesive polymer has a repeating unit represented by the following general formula 1-1 as the repeating unit of [b];
Formula 1-1:

In the Formula 1-1, ^{R 1} and L are respectively the same meanings as ^{R 1} and L in the above general formula 1.
[6]
The laminate according to any one of [1] to [5], wherein the adhesive polymer has a repeating unit represented by the following general formula 2-2 as the repeating unit of [a].
Formula 2-2

In the Formula 2-2, ^{R 5} and ^{R 8} are the same meanings as ^{R 5} and ^{R 8} in the general formula 2.
[7]
The laminate according to any one of [1] to [6], wherein the cellulose ester constituting the cellulose ester resin layer is cellulose acylate.
[8]
A polarizing plate comprising the laminate according to any one of [1] to [7] and a polarizer.
[9]
The image display apparatus which has a polarizing plate as described in [8].

In the present specification, the numerical range represented by “to” means that the numerical values described before and after it are included as the lower limit value and the upper limit value.

In the present specification, when there are a plurality of substituents, linking groups, and the like (hereinafter referred to as substituents) indicated by specific symbols, or when a plurality of substituents are specified simultaneously or alternatively, It means that a substituent etc. may mutually be same or different. The same applies to the definition of the number of substituents and the like. Further, when a plurality of substituents and the like are close (especially adjacent), they may be connected to each other or condensed to form a ring.

In this specification, about the display of a compound, it uses in the meaning containing its salt and its ion besides the compound itself. In addition, it means that a part of the structure is changed (modified) within a range where the desired effect is exhibited.
In addition, as a salt of a compound, for example, an acid addition salt of a compound formed with a compound and an inorganic acid or an organic acid, or a base addition salt of a compound formed with a compound and an inorganic base or an organic basic acid Etc. In addition, examples of the ion of the compound include an ion including a skeleton of the compound formed by dissociating the salt of the above-described compound.
In the present specification, a substituent that does not specify substitution or non-substitution (the same applies to a linking group) means that the group may have an arbitrary substituent as long as a desired effect is achieved. . This is also the same for compounds that do not specify substitution or non-substitution.
In the present specification, the term “substituent” includes groups selected from the following substituent group T unless otherwise specified. In addition, when only a substituent having a specific range is described (for example, when only described as “alkyl group”), a corresponding group of the following substituent group T (in the above case, an alkyl group) The preferred range in FIG.
In the present specification, when the number of carbon atoms of a certain group is defined, this number of carbons means the total number of carbon atoms in the group. That is, when this group is a form further having a substituent, it means the total number of carbon atoms including this substituent.
In this specification, the term “(meth) acrylic acid” is used to include both methacrylic acid and acrylic acid. The same applies to “(meth) acrylamide”. In this specification, the term “acrylic acid” is used in a broader sense than usual. That is, “acrylic acid” is used to include all compounds having the structure of R ^A —C (═CR ^B ₂ ) COOH (R ^A and R ^B each independently represent a hydrogen atom or a substituent, provided that , When R ^A is methyl, means methacrylic acid)). The same applies to “acrylamide”.

Substituent group T:
An alkyl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 12 carbon atoms, particularly preferably 1 to 8 carbon atoms such as a methyl group, an ethyl group, an isopropyl group, a tert-butyl group, an n-octyl group, n-decyl group, n-hexadecyl group, etc.), cycloalkyl group (preferably having 3 to 20, more preferably 3 to 12, particularly preferably 3 to 8 carbon atoms, cyclopropyl group) , A cyclopentyl group, a cyclohexyl group, etc.), an alkenyl group (preferably having 2 to 20 carbon atoms, more preferably 2 to 12 carbon atoms, particularly preferably 2 to 8 carbon atoms such as vinyl group, allyl group, 2- Butenyl group, 3-pentenyl group, etc.), alkynyl group (preferably having 2 to 20 carbon atoms, more preferably 2 to 12 carbon atoms, particularly preferred) 2-8, for example, propargyl group, 3-pentynyl group, etc.), aryl group (preferably 6-30 carbon atoms, more preferably 6-20, particularly preferably 6-12, For example, a phenyl group, a biphenyl group, a naphthyl group, etc.), an amino group (preferably having a carbon number of 0 to 20, more preferably 0 to 10, particularly preferably 0 to 6, such as an amino group, methylamino Group, dimethylamino group, diethylamino group, dibenzylamino group, etc.), alkoxy group (preferably having 1 to 20 carbon atoms, more preferably 1 to 12, particularly preferably 1 to 8, such as methoxy Group, ethoxy group, butoxy group, etc.), aryloxy group (preferably having 6 to 20 carbon atoms, more preferably 6 to 16 carbon atoms). Particularly preferred is 6 to 12, for example, phenyloxy group, 2-naphthyloxy group, etc.), acyl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 1 carbon atoms). 12 such as an acetyl group, a benzoyl group, a formyl group, and a pivaloyl group), an alkoxycarbonyl group (preferably having 2 to 20, more preferably 2 to 16, and particularly preferably 2 to 12 carbon atoms). For example, methoxycarbonyl group, ethoxycarbonyl group, etc.), aryloxycarbonyl group (preferably having 7 to 20, more preferably 7 to 16, particularly preferably 7 to 10 carbon atoms such as phenyloxy A carbonyl group, etc.), an acyloxy group (preferably having 2 to 20 carbon atoms, more preferably 2 to 16, particularly preferably 2 to 10, and examples thereof include an acetoxy group and a benzoyloxy group. ), An acylamino group (preferably having 2 to 20 carbon atoms, more preferably 2 to 16 and particularly preferably 2 to 10 such as acetylamino group and benzoylamino group), alkoxycarbonylamino group ( Preferably it has 2 to 20 carbon atoms, more preferably 2 to 16 carbon atoms, particularly preferably 2 to 12 carbon atoms, such as a methoxycarbonylamino group, and an aryloxycarbonylamino group (preferably 7 to 7 carbon atoms). 20, more preferably 7 to 16, particularly preferably 7 to 12, and examples thereof include a phenyloxycarbonylamino group), a sulfonylamino group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms). And particularly preferably 1 to 12, for example, methanesulfonylamino group, benzenesulfonate Amino groups, etc.), sulfamoyl groups (preferably having 0 to 20 carbon atoms, more preferably 0 to 16 carbon atoms, particularly preferably 0 to 12 carbon atoms such as sulfamoyl group, methylsulfamoyl group, dimethylsulfayl group). And a carbamoyl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 carbon atoms, particularly preferably 1 to 12 carbon atoms such as a carbamoyl group and a methylcarbamoyl group). , Diethylcarbamoyl group, phenylcarbamoyl group, etc.), alkylthio group (preferably having 1 to 20, more preferably 1 to 16, particularly preferably 1 to 12 carbon atoms, such as methylthio group and ethylthio group) Arylthio group (preferably having 6 to 20 carbon atoms, More preferably, it is 6 to 16, particularly preferably 6 to 12, and examples thereof include a phenylthio group.), A sulfonyl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16, and particularly preferably 1 to 1). 12 such as a mesyl group and a tosyl group), a sulfinyl group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16 and particularly preferably 1 to 12, such as a methanesulfinyl group, Benzenesulfinyl group, etc.), urethane group, ureido group (preferably having 1 to 20 carbon atoms, more preferably 1 to 16, particularly preferably 1 to 12, such as ureido group, methylureido group, phenyl group) Ureido groups, etc.), phosphoric acid amide groups (preferably having 1-20 carbon atoms, more preferably 1-16, 1 to 12 is preferable, and examples thereof include diethyl phosphoric acid amide and phenyl phosphoric acid amide. ), Hydroxy group, mercapto group, halogen atom (eg fluorine atom, chlorine atom, bromine atom, iodine atom), cyano group, sulfo group, carboxyl group, nitro group, hydroxamic acid group, sulfino group, hydrazino group, imino group, Heterocyclic group (preferably having 1 to 30 carbon atoms, more preferably 1 to 12 carbon atoms, and examples of the hetero atom include a nitrogen atom, an oxygen atom and a sulfur atom. A condensed ring is preferable, and specific examples include imidazolyl, pyridyl, quinolyl, furyl, piperidyl, morpholino, benzoxazolyl, benzimidazolyl, benzthiazolyl, and the like. (Preferably having 3 to 40 carbon atoms, more preferably 3 to 30, and particularly preferably 3 to 24, In example, a trimethylsilyl group, etc. triphenylsilyl group).
These substituents may further have a substituent. Moreover, when there are two or more substituents, they may be the same or different. Further, adjacent substituents may be connected to each other to form a ring.

The laminate of the present invention is excellent in adhesion between layers and can effectively suppress the permeation of moisture even if it is made thin. The laminate of the present invention can effectively suppress the deterioration of the polarizer under high temperature and high humidity conditions by overlapping with the polarizer.
The polarizing plate and the image display device of the present invention have the laminate of the present invention that exhibits the above effects, and the deterioration of the polarizer can be effectively suppressed even under severe high temperature and high humidity conditions.
In the present specification, the degree of suppressing the deterioration of the polarizer under high temperature and high humidity conditions is also referred to as “polarizer durability” or “polarizing plate durability”.
The above and other features and advantages of the present invention will become more apparent from the following description, with reference where appropriate to the accompanying drawings.

FIG. 1 is a cross-sectional view showing an embodiment of the laminate of the present invention. FIG. 2 is a schematic diagram showing an outline of an embodiment of a liquid crystal display device including a polarizing plate incorporating the polarizing plate protective film of the present invention.

[Laminate]
As shown in FIG. 1, the laminate 10 of the present invention has a cellulose ester resin layer 11 and an adhesive polymer layer 12 provided directly on the cellulose ester resin layer 11. Details of the cellulose ester resin layer 11 and the adhesive polymer layer 12 will be described later. As shown in FIG. 1, the laminate of the present invention may have an adhesive polymer layer 12 provided on one side of the cellulose ester resin layer 11 or an adhesive polymer layer 12 provided on both sides. Also good. More preferably, the laminate 10 of the present invention has a form in which the adhesive polymer layer 12 is provided on one side of the cellulose ester resin layer 11.
As the adhesive polymer layer, two or more adhesive polymer layers having different composition ratios may be provided on the cellulose ester resin layer.

Further, the laminate of the present invention may have various functional layers (not shown) specialized for specific functions in addition to the cellulose ester resin layer 11 and the adhesive polymer layer 12. Examples of such a functional layer include a hard coat layer, an antireflection layer, a light scattering layer, an antifouling layer, and an antistatic layer.

<Adhesive polymer layer>
The adhesion polymer layer which comprises the laminated body of this invention is demonstrated.
In the present invention, the “adhesive polymer layer” means a layer containing an adhesive polymer described later in an amount of 50% by mass or more. The content of the adhesive polymer in the adhesive polymer layer is preferably 60% by mass or more, more preferably 70% by mass or more, further preferably 80% by mass or more, and particularly preferably 85% by mass or more. The higher the content of the adhesive polymer, the higher the adhesiveness with the cellulose ester resin layer, which is preferable. Therefore, the content of the adhesive polymer in the adhesive polymer layer may be 100% by mass, and is usually 99% by mass or less. When the content of the adhesive polymer in the adhesive polymer layer is not 100% by mass, the balance can contain various conventional additives. Examples of such additives include plasticizers, organic acids, dyes, polymers, retardation modifiers, ultraviolet absorbers, antioxidants, matting agents, and the like.
Two or more adhesive polymers may be used in combination. That is, dense polymers having different composition ratios and / or molecular weights may be used in combination. In this case, the total amount of the adhesive polymer is within the above range.
In the present specification, the term “adhesive polymer” simply means a polymer that can be in close contact with the cellulose ester resin layer, and is merely used to facilitate understanding of the present invention. The “adhesive polymer” includes all polymers having a repeating unit as defined in the present invention regardless of the degree of adhesion. That is, in judging the gist and technical scope of the present invention, the term “adhesiveness” is not considered as an invention specific matter for interpreting the present invention in a limited manner.

-Adhesive polymer-
The adhesive polymer constituting the adhesive polymer layer has at least one repeating unit of the following [a] and at least one repeating unit of the following [b] in one molecule.

[A]:
A repeating unit derived from a (meth) acrylic ester compound, an olefin compound, a vinylidene compound or a cyclic olefin compound and having a solubility parameter δt calculated by the Hoy method of 13.5 to 19.5.

[B]:
(Meth) acrylic acid ester compounds, (meth) acrylic acid compounds, (meth) acrylamide compounds, vinyl acetate compounds, vinyl ketone compounds, maleic anhydride compounds or repeating units derived from styrene compounds or ethylenically unsaturated other than these repeating units A repeating unit derived from a compound having a bond and having a solubility parameter δt calculated by the Hoy method of 20.0 to 26.0.

The solubility parameter δt is literature ^{"Properties of Polymers 3 rd, ELSEVIER} , (1990)" The δt obtained for Amorphous Polymers according to the 214-220 pages, "2) Method of Hoy (1985,1989)" column of Meaning and calculated according to the description in the above column of the above document. Units of the solubility parameter δt in the present invention are "(cal ^/ cm ^{3) 1/2."}

The repeating unit [a] is not particularly limited as long as the above [a] is satisfied.
When the repeating unit satisfying the above [a] is derived from a (meth) acrylic acid ester compound, examples of the structure of the repeating unit include paragraphs [0021] to [0023] of JP-A No. 2004-323770, Reference may be made to paragraphs [0024] to [0059] of Japanese Unexamined Patent Publication No. 2014-185196.
Moreover, when the above [a] is a repeating unit derived from a (meth) acrylic acid ester compound, it is more preferably a repeating unit derived from a (meth) acrylic acid alkyl ester compound or a (meth) acrylic acid cycloalkyl ester compound. . The alkyl group of this (meth) acrylic acid alkyl ester compound may be linear or branched. The alkyl group constituting the (meth) acrylic acid alkyl ester compound preferably has 1 to 30 carbon atoms, more preferably 3 to 30 carbon atoms, still more preferably 4 to 20 carbon atoms, still more preferably 5 to 18 carbon atoms, and even more preferably 6 to 16 carbon atoms. .
Specific examples of the (meth) acrylic acid ester compound and (meth) acrylic acid cycloalkyl ester compound for deriving the repeating unit [a] above include, for example, propyl acrylate, isopropyl acrylate, n-butyl acrylate, acrylic acid iso-butyl, sec-butyl acrylate, tert-butyl acrylate, hexyl acrylate, cyclohexyl acrylate, 2-ethylhexyl acrylate, dodecyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, isopropyl methacrylate, Mention may be made of n-butyl methacrylate, hexyl methacrylate, cyclohexyl methacrylate, 2-ethylhexyl methacrylate and dodecyl methacrylate.

When the repeating unit [a] is derived from an olefin compound, for example, paragraph [0015] of JP-A No. 2000-159817 can be referred to as the structure of such a repeating unit.
Specific examples of the olefin compound for deriving the repeating unit [a] include ethylene, propylene, isoprene, butadiene, isobutene and vinyl chloride.

When the repeating unit [a] is derived from a vinylidene compound, examples of the structure of the repeating unit include paragraphs [0032] to [0041] of JP-A-2015-44967 and JP-A-8-67793. Paragraphs [0008] to [0009] and the like can be referred to.
Specific examples of the vinylidene compound for deriving the repeating unit [a] include, for example, vinylidene chloride, vinylidene fluoride, tetrafluoroethylene, trifluoroethylene chloride, and perfluoroalkoxytrifluoroethylene.

When the repeating unit [a] is derived from a cyclic olefin compound, specific examples of the cyclic olefin compound leading to the repeating unit [a] include, for example, cyclohexene, norbornene, tetracyclododecene, and the like. Mention may be made of the derived compounds.

The adhesive polymer preferably has a repeating unit represented by the following general formula 2 as the repeating unit [a].
General formula 2:

In General Formula 2, R ⁵ represents a hydrogen atom or an alkyl group.
The alkyl group that can be adopted as R ⁵ may be linear or branched. The alkyl group preferably has 1 to 10 carbon atoms, more preferably 1 to 5 carbon atoms, and still more preferably 1 to 3 carbon atoms. R ⁵ is more preferably methyl or ethyl, and even more preferably methyl.
R ⁵ is preferably a hydrogen atom or methyl.

R ⁶ and R ⁷ represent a hydrogen atom, an alkyl group, an aryl group or an alkoxycarbonyl group.
The alkyl group which can be taken as R ⁶ and R ⁷ may be linear or branched. The alkyl group preferably has 1 to 10 carbon atoms, more preferably 1 to 5 carbon atoms, and still more preferably 1 to 3 carbon atoms. The alkyl group that can be taken as R ⁶ and R ⁷ is more preferably methyl or ethyl, and even more preferably methyl.
The aryl group that can be adopted as R ⁶ and R ⁷ preferably has 6 to 20 carbon atoms, more preferably 6 to 15 carbon atoms, particularly preferably 6 to 12 carbon atoms, and particularly preferably phenyl.
The alkoxycarbonyl group that can be employed as R ⁶ and R ⁷ preferably has 2 to 10 carbon atoms, and more preferably 2 to 5 carbon atoms. The alkoxycarbonyl group which can be taken as R ⁶ and R ⁷ is more preferably methoxycarbonyl or ethoxycarbonyl.
R ⁸ represents an alkyl group having 1 to 20 carbon atoms or a cycloalkyl group having 3 to 20 carbon atoms.
The alkyl group having 1 to 20 carbon atoms that can be taken as R ⁸ may be linear or branched. The alkyl group preferably has 1 to 15 carbon atoms, more preferably 1 to 12, more preferably 1 to 10, still more preferably 1 to 8, and still more preferably 1 to 6.
In addition, when the alkyl group having 1 to 20 carbon atoms that can be taken as R ⁸ has a substituent, a halogen atom is preferable, and a fluorine atom is more preferable.
The cycloalkyl group having 3 to 20 carbon atoms that can be adopted as R ⁸ has more preferably 4 to 15 carbon atoms, and further preferably 5 to 12 carbon atoms. The cycloalkyl group having 3 to 20 carbon atoms that can be employed as R ⁸ is preferably in a form in which the substituents of the cycloalkyl group are connected to each other to form a condensed ring.
Further, when the cycloalkyl group having 3 to 20 carbon atoms that can be taken as R ⁸ has a substituent, it is preferably an alkyl group (which may be linear or branched), and has 1 to 4 carbon atoms. An alkyl group is more preferable, and methyl, ethyl, or t-butyl is more preferable.

In the adhesive polymer, the molar amount of the repeating unit represented by the general formula 2 in the total molar amount of the repeating unit [a] is preferably 50 mol% or more, and 70 mol% or more. More preferably, it is 80 mol% or more, more preferably 90 mol% or more. The adhesive polymer preferably has a molar amount of the repeating unit represented by the general formula 2 in the total molar amount of the repeating unit [a] of 100 mol% or less. It is also preferred that all of the repeating units [a] contained therein are repeating units represented by the general formula 2.

The adhesive polymer more preferably has a repeating unit represented by the following general formula 2-2 as the repeating unit of the above [a].
Formula 2-2

In General Formula 2-2, R ⁵ and R ⁸ have the same meanings as R ⁵ and R ⁸ in General Formula 2, respectively, and preferred forms are also the same.

In the adhesive polymer, the molar amount of the repeating unit represented by the general formula 2-2 in the total molar amount of the repeating unit [a] is preferably 50 mol% or more, and 70 mol% or more. More preferably, it is more preferably 80 mol% or more, and still more preferably 90 mol% or more. The adhesive polymer preferably has a molar amount of the repeating unit represented by the general formula 2-2 in the total molar amount of the repeating unit [a] of 100 mol% or less. It is also preferred that all of the repeating units [a] contained in the conductive polymer are repeating units represented by the general formula 2-2.

Preferred examples of the repeating unit [a] are shown below as structural formulas, but the present invention is not limited to these examples.

In the above repeating unit [a], the (meth) acrylic acid ester compound includes a (meth) acrylic acid compound.

The above A-32 can also be interpreted as a repeating unit derived from a vinylidene compound. However, in the present invention, even if it can be interpreted as a vinylidene compound, when the structure consists of only a carbon atom and a hydrogen atom, it is classified as an olefin compound instead of a vinylidene compound.

The repeating unit [b] is not particularly limited as long as the above [b] is satisfied.
When the repeating unit satisfying the above [b] is derived from a (meth) acrylic acid ester compound, examples of the structure of the repeating unit include paragraphs [0021] to [0023] of JP-A-2004-323770. Reference may be made to [0024] to [0059] of JP 2014-185196.
Specific examples of the (meth) acrylic acid ester compound for deriving the repeating unit [b] include, for example, 2-hydroxyethyl acrylate, 2-acetoacetoxyethyl acrylate, 2-isocyanatoethyl acrylate, and methacrylic acid. Examples thereof include 2-hydroxyethyl, 2-dimethylaminoethyl methacrylate, 2-diethylaminoethyl methacrylate, and 2-isocyanatoethyl methacrylate.

When the repeating unit [b] is derived from a (meth) acrylic acid compound, refer to paragraphs [0020] to [0027] of JP 2002-212221 A, for example, as the structure of the repeating unit. be able to.
Specific examples of the (meth) acrylic acid compound from which the repeating unit [b] is derived include acrylic acid and its metal salt, and methacrylic acid and its metal salt.

A preferable structure when the repeating unit [b] is derived from a (meth) acrylamide compound is as shown in the structural formula exemplified later.

When the repeating unit [b] is derived from a vinyl acetate compound, for example, paragraphs [0007] to [0008] of JP-A-2002-338609 can be referred to as the structure of such a repeating unit. .
Specific examples of the vinyl acetate compound from which the repeating unit [b] is derived include vinyl acetate, vinyl propionate, vinyl pivalate, isopropenyl acetate and the like. Thus, in the present invention, “vinyl acetate compound” is used to include a compound in which a hydrogen atom of vinyl acetate is substituted.

When the repeating unit [b] is derived from a vinyl ketone compound, examples of the structure of the repeating unit include, for example, paragraphs [0010] to [0017] of JP-A-2007-230940 and JP-A-7-291886. Paragraphs [0009] to [0011] and the like can be referred to.
Specific examples of the vinyl ketone compound for deriving the repeating unit [b] include methyl vinyl ketone and ethyl vinyl ketone.
In the present invention, the vinyl ketone compound means a compound having the following structure and not an acrylate compound, an acrylamide compound, or an acrylic acid compound.

When the repeating unit [b] is derived from a maleic anhydride compound, examples of the structure of the repeating unit include, for example, paragraphs [0027] to [0029] of JP-A-2006-1111710 and JP-A-2008-156400. Reference may be made to paragraphs [0013] to [0015] and the like of the publication.
Specific examples of the maleic anhydride compound for deriving the repeating unit [b] include maleic anhydride, N-methylmaleimide, N-cyclohexylmaleimide, N-phenylmaleimide and the like. Thus, in the present invention, “maleic anhydride compound” is used to include a compound derived from maleic anhydride.

A preferable structure when the repeating unit [b] is derived from a styrene compound is as shown in the structural formula exemplified later.

The repeating unit [b] may be a repeating unit derived from a compound having an ethylenically unsaturated bond (carbon-carbon double bond) other than the repeating unit derived from each compound described above.

The adhesive polymer preferably has a repeating unit represented by the following general formula 1 as the repeating unit [b].
General formula 1:

In General Formula 1, R ¹ , R ² and R ³ have the same meanings as R ⁵ , R ⁶ and R ⁷ in General Formula 2, respectively, and preferred forms are also the same.

L is a single bond, or a divalent linking group selected from an alkylene group, an arylene group, —C (═O) —, —O— and —N (R ⁴ ) —, or 2 of these linking groups. A divalent linking group formed by combining more than one species is shown. R ⁴ has the same meaning as R ¹ above, and the preferred form is also the same.
In the divalent linking group formed by combining two or more of the above, the number of the linking groups to be combined is not particularly limited, but is preferably 2 to 9, and more preferably 2 or 3. Also, the combination of the linking groups is not particularly limited. For example, the combination of —C (═O) —, —O— and an alkylene group, or the combination of —C (═O) —, —O— and an arylene group. And a combination of —C (═O) —, —O— and an alkylene group is more preferred. Among these, it is more preferable that L is a linking group containing —C (═O) —, and —C (═O) — is bonded to the main chain (the carbon atom to which R ¹ is bonded).

The alkylene group that can be taken as L is preferably a straight chain. The alkylene group preferably has 1 to 5 carbon atoms, more preferably 1 to 4, more preferably 1 to 3, and particularly preferably 2.
The arylene group that can be taken as L preferably has 6 to 20 carbon atoms, more preferably 6 to 15 carbon atoms, particularly preferably 6 to 12 carbon atoms, and particularly preferably phenylene.

In the adhesive polymer, the molar amount of the repeating unit represented by the general formula 1 in the total molar amount of the repeating unit [b] is preferably 50 mol% or more, and 70 mol% or more. More preferably, it is 80 mol% or more, more preferably 90 mol% or more. The adhesive polymer preferably has a molar amount of the repeating unit represented by the general formula 1 in the total molar amount of the repeating unit [b] of 100 mol% or less. It is also preferred that all of the repeating units [b] contained therein are repeating units represented by the above general formula 1.

The adhesive polymer more preferably has a repeating unit represented by the following general formula 1-1 as the repeating unit [b].
Formula 1-1:

In general formula 1-1, R ¹ and L have the same meanings as R ¹ and L in general formula 1, respectively, and preferred forms are also the same.

In the adhesive polymer, the molar amount of the repeating unit represented by the general formula 1-1 in the total molar amount of the repeating unit [b] is preferably 50 mol% or more, and 70 mol% or more. More preferably, it is more preferably 80 mol% or more, and still more preferably 90 mol% or more. The adhesive polymer preferably has a molar amount of the repeating unit represented by the general formula 1-1 in the total molar amount of the repeating unit [b] of 100 mol% or less. It is also preferred that all of the repeating units [b] contained in the functional polymer are repeating units represented by the general formula 1-1.

Preferred examples of the repeating unit [b] are shown below as structural formulas, but the present invention is not limited to these examples.

The adhesive polymer is not particularly limited as to the content of each repeating unit as long as it has both the repeating unit [a] and the repeating unit [b]. That is, the adhesive polymer may have a repeating unit other than the repeating unit [a] and the repeating unit [b].

From the viewpoint of further improving the affinity between the adhesive polymer layer and the cellulose ester resin layer and obtaining a laminate excellent in interlayer adhesion, the above-mentioned [occupying in the total molar amount of the monomer components constituting the adhesive polymer [ The molar amount of the repeating unit (b) is preferably 5 mol% or more, more preferably 10 mol% or more, and further preferably 20 mol% or more. The molar amount of the repeating unit (b) occupying in the total molar amount of the monomer component constituting the adhesive polymer is preferably 95 mol% or less, more preferably 90 mol% or less, and even more preferably 80 mol% or less. .

In addition, from the viewpoint of obtaining a laminate having both adhesion and low moisture permeability at a higher level, the molar amount of the repeating unit [a] in the total molar amount of the monomer component constituting the adhesive polymer is determined. It is preferably 5 mol% or more, more preferably 10 mol% or more, more preferably 20 mol% or more, further preferably 40 mol% or more, and 50 mol% or more. It is particularly preferred. The molar amount of the repeating unit [a] in the total molar amount of the monomer component constituting the adhesive polymer is preferably 95 mol% or less, and more preferably 90 mol% or less.

In the adhesive polymer, the content of the repeating unit [a] and the content of the repeating unit [b] is preferably 50% by mass or more, more preferably 70% by mass or more. Preferably, it is 80 mass% or more, more preferably 90 mass% or more. The adhesive polymer is also preferably in the form of the repeating unit [a] and the repeating unit [b].

In the adhesive polymer, the content of the repeating unit [a] and the content of the repeating unit [b] are in a molar ratio: [[a] repeating unit] / [[b] repeating unit. ] = 95/5 to 10/90, preferably [repeat unit of [a]] / [repeat unit of [b]] = 95/5 to 30/70, more preferably [[a ] [Repeat unit] / [repeat unit of [b]] = 92/8 to 50/50 is more preferable, and [repeat unit of [a]] / [repeat unit of [b]] = 90/10. It is more preferable to satisfy ˜60 / 40, and it is more preferable to satisfy [repeat unit of [[a]] / [repeat unit of [b]] = 90/10 to 75/25.

The adhesive polymer may be a random polymer or a block polymer.

The reason why the layer using the polymer having the repeating unit [a] and the polymer having the repeating unit [b] is excellent in adhesion to the cellulose ester resin layer is not clear, but is estimated as follows. That is, the solubility parameter δt of the repeating unit in the condition [b] is relatively close to the solubility parameter δt of the cellulose ester, and it is considered that a partial gradient occurs in the affinity with the cellulose ester in the adhesive polymer layer. . And it is estimated that a part with a comparatively high affinity with a cellulose ester interacts effectively with a cellulose-ester resin layer, and improves interlayer adhesiveness. Moreover, since the adhesive polymer also has the repeating unit [a] having a low solubility parameter δt, the moisture permeability of the laminate can be effectively suppressed.
Furthermore, in the laminate in which the adhesive polymer layer and the cellulose ester resin layer are laminated, due to the laminated structure of different materials, diffusion of moisture that has entered inside is suppressed, and moisture permeability is more effectively suppressed. It is considered a thing.

The lower limit of the weight average molecular weight of the adhesive polymer used in the present invention is preferably 5,000 or more, more preferably 10,000 or more, and 15,000 or more from the viewpoint of the film surface shape. More preferably, it is more preferably 35,000 or more, and most preferably 75,000 or more. On the other hand, the upper limit value of the weight average molecular weight of the adhesive polymer is preferably 2,000,000 or less, more preferably 1,500,000 or less, and 1,000, from the viewpoint of film forming properties. It is more preferable that it is 15,000 or less, it is further preferable that it is 750,000 or less, it is further more preferable that it is 500,000 or less, and it is most preferable that it is 350,000 or less.

The film thickness of the adhesive polymer layer is not particularly limited, preferably 1 to 25 μm, more preferably 1 to 20 μm, and particularly preferably 1 to 15 μm.

[Cellulose ester resin layer]
The cellulose ester resin layer which comprises the laminated body of this invention is a layer which contains 50 mass% or more of cellulose esters in a layer. 60 mass% or more is preferable, as for content of the cellulose ester in a cellulose-ester resin layer, 70 mass% or more is more preferable, 80 mass% or more is further more preferable, and 85 mass% or more is further more preferable. The upper limit of the content of the cellulose ester in the cellulose ester resin layer is usually 96% by mass or less, preferably 95% by mass or less, and more preferably 92% by mass or less. In this case, the remainder excluding the cellulose ester includes, for example, an additive described later.

<Cellulose ester>
The cellulose ester used as a raw material in the production of the cellulose ester resin layer of the present invention will be described.
Examples of cellulose used as a raw material for the cellulose ester used in the present invention include cotton linter and wood pulp (hardwood pulp, softwood pulp). May be. Raw material cellulose is, for example, Marusawa and Uda, “Plastic Materials Course (17) Fibrous Resin”, Nikkan Kogyo Shimbun (published in 1970) and JIII Journal of Technical Publication No. 2001-1745 (page 7). To page 8) can be used.
As a cellulose ester, the cellulose ester normally used for manufacture of a cellulose-ester film can be used without a restriction | limiting at all. Of these, cellulose acylate is preferably used.

(Cellulose acylate)
As the cellulose acylate used in the present invention, a cellulose acylate commonly used for producing a cellulose acylate film can be used without any limitation.
The β-1,4-bonded glucose unit constituting cellulose has free hydroxy groups at the 2nd, 3rd and 6th positions. Cellulose acylate is a polymer obtained by acylating a part of these hydroxy groups with an acyl group.
The degree of acyl substitution (hereinafter sometimes simply referred to as “degree of substitution”) indicates the degree of acylation of the hydroxy group of cellulose located at the 2-position, 3-position and 6-position, and is 2 for all glucose units. When the hydroxy groups at the 3rd, 6th and 6th positions are all acylated, the total degree of acyl substitution is 3. For example, in all glucose units, when only the 6-position is all acylated, the total acyl substitution degree is 1. Similarly, the total acyl substitution degree is 1 when all of either the 6-position and the 2-position are acylated in each glucose unit in all hydroxy groups of all glucose.
That is, the degree of substitution indicates the degree of acylation, assuming that 3 is when all the hydroxy groups in the glucose molecule are all acylated.
The degree of substitution of cellulose acylate is described in Tezuka et al., Carbohydrate. Res. , 273, 83-91 (1995), or according to the method prescribed in ASTM-D817-96.

The total acyl substitution degree of the cellulose acylate used in the present invention is preferably 1.50 or more and 3.00 or less, more preferably 2.00 to 2.97, from the viewpoint of moisture permeability, and 2.30 or more. More preferably, it is less than 2.97, and particularly preferably 2.30 to 2.95.

The acyl group of the cellulose acylate used in the present invention is not particularly limited, and may be a form having one kind of acyl group or a form having two or more kinds of acyl groups. The cellulose acylate that can be used in the present invention preferably has an acyl group having 2 or more carbon atoms as a substituent. The acyl group having 2 or more carbon atoms is not particularly limited, and may be an aliphatic acyl group or an aromatic acyl group. Specific examples of the acyl group having 2 or more carbon atoms include acetyl, propionyl, butanoyl, heptanoyl, hexanoyl, octanoyl, decanoyl, dodecanoyl, tridecanoyl, tetradecanoyl, hexadecanoyl, octadecanoyl, isobutanoyl, tert-butanoyl, cyclohexanecarbonyl Oleoyl, benzoyl, naphthylcarbonyl, cinnamoyl and the like. Among these, acetyl, propionyl, butanoyl, dodecanoyl, octadecanoyl, tert-butanoyl, oleoyl, benzoyl, naphthylcarbonyl, and cinnamoyl are preferable, and acetyl, propionyl, and butanoyl are more preferable.

Cellulose acetate using only an acetyl group as the acyl group of cellulose acylate can be preferably used in the present invention. The total acyl substitution degree of this cellulose acetate is 2.00 to 3 from the viewpoint of moisture permeability and optical properties. Is preferably 0.000, more preferably 2.20 to 3.00, still more preferably 2.30 to 3.00, still more preferably 2.30 to 2.97, Particularly preferred is 2.30 to 2.95.

A mixed fatty acid ester having two or more kinds of acyl groups can also be preferably used as the cellulose acylate in the present invention. Also, mixed acid esters having fatty acid acyl groups and substituted or unsubstituted aromatic acyl groups described in paragraphs 0023 to 0038 of JP-A-2008-20896 can be preferably used. Among them, the acyl group of the mixed fatty acid ester preferably includes an acetyl group and an acyl group having 3 to 4 carbon atoms. When the mixed fatty acid ester contains an acetyl group as an acyl group, the degree of acetyl substitution is preferably less than 2.5 and more preferably less than 1.9. On the other hand, when an acyl group having 3 to 4 carbon atoms is contained, the degree of substitution of the acyl group having 3 to 4 carbon atoms is preferably 0.1 to 1.5, and preferably 0.2 to 1.2. Is more preferable, and 0.5 to 1.1 is particularly preferable.
As the cellulose ester resin layer used in the present invention, it is also preferable to employ a resin layer composed of a plurality of layers composed of different cellulose acylates by a co-casting method described later.

The cellulose ester or cellulose acylate used in the present invention preferably has a degree of polymerization of 250 to 800, more preferably 300 to 600. The number average molecular weight of the cellulose ester or cellulose acylate used in the present invention is preferably 40000 to 230,000, more preferably 60000 to 230,000, and most preferably 75,000 to 200000. The degree of polymerization can be determined by ordering the number average molecular weight measured in terms of polystyrene by gel permeation chromatography (Gel Permeation Chromatography; GPC) with the molecular weight of the glucopyranose unit of cellulose ester or cellulose acylate.

The cellulose ester used in the present invention can be synthesized by a conventional method. For example, cellulose acylate can be synthesized using an acid anhydride or acid chloride as an acylating agent. When the acylating agent is an acid anhydride, an organic acid (for example, acetic acid) or methylene chloride is used as a reaction solvent. Further, a protic catalyst such as sulfuric acid can be used as the catalyst. When the acylating agent is an acid chloride, a basic compound can be used as a catalyst. In general industrial production of cellulose acylate, an organic acid (acetic acid, propionic acid, butyric acid, etc.) or an acid anhydride (acetic anhydride, propionic anhydride, butyric anhydride, etc.) corresponding to the desired acyl group in cellulose is used. Is used to esterify the hydroxy group.
For example, a cellulose derived from cotton linter or wood pulp is used as a raw material, and this is activated with an organic acid such as acetic acid and then esterified with an organic acid having a desired structure in the presence of a sulfuric acid catalyst. Acylate can be obtained. When an organic acid anhydride is used as the acylating agent, cellulose is generally esterified using an excess amount of the organic acid anhydride relative to the amount of hydroxy groups present in the cellulose.
Cellulose acylate can also be synthesized, for example, by the method described in JP-A-10-45804.

Further, in the cellulose ester resin layer of the present invention, other resins (for example, (meth) acrylic resin etc.) can be used in combination with the cellulose ester within a range not impairing the effects of the present invention. The content of the other resin in the cellulose ester film is preferably 40% by mass or less, more preferably 30% by mass or less, further preferably 20% by mass or less, and further preferably 15% by mass or less in the cellulose ester film. 10 mass% or less is still more preferable.

<Formation of cellulose ester resin layer>
Next, the formation of the cellulose ester resin layer will be described.
The formation of the cellulose ester resin layer is not particularly limited. For example, the cellulose ester resin layer is preferably formed by a melt film formation method or a solution film formation method (solvent casting method). More preferably, it is formed by a membrane method (solvent cast method). Examples of film production using the solvent cast method are described in U.S. Pat. Nos. 2,336,310, 2,367,603, 2,492,078, 2,492,977, Nos. 2,492,978, 2,607,704, 2,739,069 and 2,739,070, British Patent Nos. 640731 and 736892 And the Japanese Patent Publications Nos. 45-4554, 49-5614, JP-A-60-176834, JP-A-60-203430, and JP-A-62-115035. Moreover, the said cellulose-ester resin layer may be extended | stretched. For the stretching method and conditions, refer to, for example, JP-A-62-115035, JP-A-4-152125, 4-284221, 4-298310, and 11-48271. can do.

(Casting)
As a method of casting the solution, a method of uniformly extruding the prepared dope from a pressure die onto a metal support, a doctor blade for adjusting the film thickness with a blade of the dope once cast on a support of metal or the like And a method using a reverse roll coater that adjusts with a reversely rotating roll, and a method using a pressure die is preferred. The pressure die includes a coat hanger type and a T die type, and any of them can be preferably used. In addition to the methods listed here, it can be carried out by various known methods for casting a cellulose ester solution, and each condition is set in consideration of differences in the boiling point of the solvent used. can do.

The cellulose ester resin layer may be a single layer or multiple layers, and in the case of multiple layers, it is preferable to use a lamination casting method such as a co-casting method, a sequential casting method, or a coating method. In particular, the simultaneous co-casting (also referred to as simultaneous multi-layer co-casting) method is particularly preferable from the viewpoint of stable production and production cost reduction.
When producing a cellulose ester resin layer by the co-casting method and the sequential casting method, first, a cellulose ester solution (also referred to as a dope) for each layer is prepared, and this solution is cast on a support.
In the co-casting method (multi-layer simultaneous casting), first, a casting dope for each layer (which may be three layers or more) is simultaneously applied from a separate slit or the like on a casting support (band or drum). The dope is extruded using a casting die that can be extruded, and the layers are cast simultaneously. It is a casting method in which after casting, the film is peeled off from the support after an appropriate time and dried to form a film. By using a co-casting die, for example, a total of three layers: a surface layer two layers formed from a surface layer dope on a casting support, and a core layer composed of a core layer dope sandwiched between these surface layers. It can be extruded and cast simultaneously on a support.

In the sequential casting method, the casting dope for the first layer is first extruded from the casting die on the casting support, cast, and dried on the second layer without drying or drying. The dope for casting is extruded from the casting die, and if necessary, the dope is cast and laminated sequentially up to the third layer or more, and peeled off from the support after a suitable time and dried. Then, a cellulose ester resin layer is formed.
In the coating method, generally, a core layer is formed into a film by a solution casting method, and a coating solution that is a target cellulose ester solution is applied to the surface layer, followed by drying to form a cellulose ester having a laminated structure. A resin layer is formed.

(Stretching)
The cellulose ester resin layer is preferably stretched after casting and drying. The stretching direction of the cellulose ester resin layer may be either the film transport direction (MD (Machine Direction) direction) or the direction orthogonal to the transport direction (TD (Transverse Direction) direction). Considering the subsequent polarizing plate processing process, the TD direction is preferable. The stretching process may be performed a plurality of times in two or more stages.

Methods for stretching in the TD direction are described in, for example, JP-A-62-115035, JP-A-4-152125, JP-A-2842211, JP-A-298310, and JP-A-11-48271. Yes. In the case of stretching in the TD direction, the film can be stretched by conveying the film while holding the film with a tenter and gradually widening the width of the tenter. Further, after the film is dried, it can be stretched using a stretching machine (preferably uniaxial stretching using a long stretching machine).
In the case of stretching in the MD direction, for example, it can be performed by adjusting the speed of the film transport roller to make the winding speed faster than the film peeling speed.

When the laminate of the present invention is used as a protective film for a polarizer (also referred to as a polarizing plate protective film), in order to suppress light leakage when the polarizing plate is viewed obliquely, the transmission axis of the polarizer and the cellulose ester An embodiment in which slow axes in the plane of the resin layer are arranged in parallel is preferable. Since the transmission axis of the roll film-like polarizer produced continuously is generally parallel to the width direction of the roll film, it is composed of the roll film-like polarizer and the roll film-like cellulose ester resin layer. In order to continuously bond the protective film, the in-plane slow axis of the roll film-shaped protective film needs to be parallel to the width direction of the cellulose ester resin layer. Therefore, it is preferable to stretch more in the TD direction.

The stretching in the TD direction is preferably 5 to 100%, more preferably 5 to 80%, and particularly preferably 5 to 40%. In the case of unstretched, the stretching is 0%. The stretching process may be performed in the middle of the film forming process, or the original fabric that has been formed and wound may be stretched. In the former case, stretching may be performed in a state including the residual solvent amount, and the residual solvent amount = (residual volatile matter mass / film mass after heat treatment) × 100% is stretched in a state of 0.05 to 50%. It is preferable to do. It is more preferable to stretch 5 to 80% in a state where the residual solvent amount is 0.05 to 5%.

<Additives>
The cellulose ester resin layer may contain an additive as long as the effects of the present invention are not impaired. Examples of the additive include conventional plasticizers, organic acids, dyes, polymers, retardation adjusting agents, ultraviolet absorbers, antioxidants, matting agents and the like. Regarding these, the description of paragraph numbers 0062 to 0097 of JP2012-155287A can be referred to, and the contents thereof are incorporated in the present specification. Examples of the additive include a peeling accelerator, an organic acid, and a polyvalent carboxylic acid derivative. With respect to these, the description of WO2015 / 005398, paragraphs 0212 to 0219 can be referred to, and the contents thereof are incorporated in the present specification. Furthermore, examples of the additive include a radical scavenger, a deterioration inhibitor, and a barbituric acid compound, which will be described later.
The content of the additive (when the cellulose ester resin layer contains two or more additives) is preferably 50 parts by mass or less with respect to 100 parts by mass of the cellulose ester. 30 parts by mass or less, more preferably 5 to 30 parts by mass.

(Plasticizer)
One preferred additive is a plasticizer. By adding a plasticizer to the cellulose ester resin layer, the hydrophobicity of the cellulose ester resin layer can be increased. This point is preferable from the viewpoint of reducing the water content of the cellulose ester resin layer. The use of such a plasticizer can reduce the occurrence of display unevenness of the image display device due to humidity when the laminate having a cellulose ester resin layer is used as a polarizing plate protective film. preferable.

The molecular weight of the plasticizer is preferably 3000 or less, more preferably 1500 or less, and still more preferably 1000 or less, from the viewpoint of obtaining the above-described effect by adding it satisfactorily. The molecular weight of the plasticizer is, for example, 300 or more, preferably 350 or more, from the viewpoint of low volatility. In the case of multimeric plasticizers, the molecular weight is the number average molecular weight.

As the plasticizer, a polyhydric ester compound of polyhydric alcohol (hereinafter also referred to as “polyhydric alcohol ester plasticizer”), a polycondensed ester compound (hereinafter also referred to as “polycondensed ester plasticizer”), And carbohydrate compounds (hereinafter also referred to as “carbohydrate derivative plasticizers”). For polyhydric alcohol ester plasticizers, WO2015 / 005398 paragraphs 0081 to 0098, for polycondensation ester plasticizers, paragraphs 00099 to 0122, and for carbohydrate derivative plasticizers, paragraphs 0123 to 0140. The contents of which are hereby incorporated by reference. The content of these plasticizers is 1 to 20 parts by mass with respect to 100 parts by mass of the resin (cellulose ester) of the layer to which the plasticizer is added from the viewpoint of achieving both the effect of adding the plasticizer and suppressing the precipitation of the plasticizer. Preferably, the content is 2 to 15 parts by mass, more preferably 5 to 15 parts by mass.
Two or more kinds of these plasticizers may be added. Also when adding 2 or more types, the specific example and preferable range of addition amount are the same as the above.

(Antioxidant)
One preferable additive may include an antioxidant. Regarding the antioxidant, the description of WO 2015/005398, paragraphs 0143 to 0165 can be referred to, and the contents thereof are incorporated in the present specification.

(Radical scavenger)
One preferred additive may include a radical scavenger. Regarding the radical scavenger, reference can be made to the description of WO 2015/005398, paragraphs 0166 to 0199, the contents of which are incorporated herein.

(Deterioration inhibitor)
As one of preferable additives, a deterioration preventing agent can be mentioned. Regarding the deterioration preventing agent, the description in WO2015 / 005398 paragraphs 0205 to 0206 can be referred to, and the contents thereof are incorporated in the present specification.

(Barbituric acid compound)
The cellulose ester resin layer can also contain a compound having a barbituric acid structure (barbituric acid compound). A barbituric acid compound is a compound which can express various functions in a cellulose-ester resin layer by adding this compound. For example, the barbituric acid compound is effective for improving the hardness of the cellulose ester resin layer. The barbituric acid compound is also effective in improving the durability against light, heat, humidity and the like of a polarizing plate provided with a cellulose ester resin layer containing this compound. With respect to the barbituric acid compound that can be added to the cellulose ester resin layer, for example, the description in paragraphs 0029 to 0060 of WO 2015/005398 can be referred to, and the contents thereof are incorporated in the present specification.

<Saponification treatment>
The cellulose ester resin layer can be improved in adhesion to a polarizer material such as polyvinyl alcohol by alkali saponification treatment.
As the saponification method, the method described in paragraph No. 0211 and paragraph No. 0212 of JP-A-2007-86748 can be used.

For example, the alkali saponification treatment for the cellulose ester resin layer is preferably performed in a cycle in which the film surface is immersed in an alkali solution, neutralized with an acidic solution, washed with water and dried. Examples of the alkaline solution include potassium hydroxide solution and sodium hydroxide solution. The concentration of hydroxide ions is preferably in the range of 0.1 to 5.0 mol / L, more preferably in the range of 0.5 to 4.0 mol / L. The alkaline solution temperature is preferably in the range of room temperature to 90 ° C, more preferably in the range of 40 to 70 ° C.

Instead of the alkali saponification treatment, easy adhesion processing as described in JP-A-6-94915 and JP-A-6-118232 may be performed.

The film thickness of the cellulose ester resin layer is preferably 1 to 80 μm, more preferably 1 to 60 μm, and further preferably 3 to 60 μm.

[Manufacturing method of laminate]
The manufacturing method of the laminated body of this invention is demonstrated.
The laminated body of this invention is not specifically limited, A normal method can be employ | adopted. In addition to the melt film forming method and the solution film forming method (solvent casting method), after preparing the cellulose ester resin layer by the method described later, the adhesive polymer layer is formed by various conventional coating methods to produce a laminate. You can also. Although there is no restriction | limiting in particular as such a coating method, A micro gravure coating system can be used preferably. In addition, even if it is a case where any application | coating method is used, if an adhesive polymer is melt | dissolved in a suitable solvent by a suitable density | concentration, a coating liquid will not be specifically limited, Coating conditions and film-forming conditions Is not particularly limited.
In addition, from the viewpoint of suitability for mass production, it can be produced by a melt casting method or a solution casting method (solvent casting method). As the melt film forming method, a production method such as a T-die method is preferably used, and a simultaneous coextrusion method is particularly preferable. As the solution casting method, it is preferable to use a lamination casting method such as the above-mentioned co-casting method, sequential casting method, coating method or the like. Is particularly preferable from the viewpoints of stable production and production cost reduction.

<Physical properties of the laminate>
(Haze)
In the laminate of the present invention, the haze measured by the following method is preferably 1% or less, more preferably 0.7% or less, and particularly preferably 0.5% or less. A laminate exhibiting such haze is excellent in transparency and suitable as a film member for a liquid crystal display device. Although the lower limit of haze is 0.001% or more, for example, it is not specifically limited.
The haze is measured in accordance with JIS K7136 (2000) using a haze meter (HGM-2DP, Suga Test Instruments) in an environment of 25 ° C. and a relative humidity of 60% using a laminate 40 mm × 80 mm.

(Film thickness)
The film thickness of the laminate of the present invention can be appropriately determined according to the application, but can be set to 5 to 100 μm, for example. When the thickness is 5 μm or more, the handling property when producing a web-like film is improved, which is preferable. Moreover, by setting it as 100 micrometers or less, it becomes easy to respond to a humidity change and it becomes easy to maintain an optical characteristic. The film thickness of the laminate is more preferably 8 to 80 μm, still more preferably 10 to 70 μm.

(Moisture permeability)
The moisture permeability of the laminate is measured under the conditions of 40 ° C. and relative humidity 90% based on JIS Z-0208.
The moisture permeability of the laminate of the present invention is preferably 1600 g / m ² / day (24 hours) or less, more preferably 1000 g / m ² / day or less, and 600 g / m ² / day or less. More preferably, it is particularly preferably 200 g / m ² / day or less. By controlling the moisture permeability of the laminated body within the above range, the liquid crystal display device mounted with the laminated body of the present invention is warped at normal temperature, high humidity, and high temperature and high humidity, and displayed during black display. Unevenness can be suppressed.

(Moisture content)
The moisture content of the laminate (equilibrium moisture content) is 25 ° C., regardless of the film thickness, so as not to impair the adhesion with a hydrophilic thermoplastic resin such as polyvinyl alcohol when used as a protective film for a polarizing plate. The water content at a relative humidity of 80% is preferably 0 to 4% by mass. The content is more preferably 0 to 2.5% by mass, and still more preferably 0 to 1.5% by mass. If the equilibrium moisture content is 4% by mass or less, the dependence of retardation on humidity changes does not become too large, and the display unevenness of the liquid crystal display device during black display after normal temperature, high humidity, and high temperature and high humidity environments is suppressed. This is also preferable.
The moisture content is measured by measuring the film sample 7 mm x 35 mm by the Karl Fischer method using a moisture meter and sample drying devices “CA-03” and “VA-05” (both manufactured by Mitsubishi Chemical Corporation). Can do. The moisture content can be calculated by dividing the moisture content (g) by the sample mass (g).

[Polarizer]
The polarizing plate of the present invention includes a polarizer and at least one laminate of the present invention as a protective film for the polarizer.

As the polarizer, for example, a film obtained by immersing and stretching a polyvinyl alcohol film in an iodine solution can be used. When using a polarizer obtained by immersing and stretching a polyvinyl alcohol film in an iodine solution, for example, the saponification surface of the cellulose ester resin layer in the laminate is bonded to at least one surface of the polarizer using an adhesive. be able to. Examples of the adhesive include an aqueous solution of polyvinyl alcohol or polyvinyl acetal (for example, polyvinyl butyral), a latex of a vinyl-based polymer (for example, polybutyl acrylate), and an ultraviolet curable adhesive. A particularly preferred adhesive is an aqueous solution of fully saponified polyvinyl alcohol.

The production method of the polarizing plate of the present invention is not particularly limited, and can be produced according to a general method. For example, there is a method in which the laminate of the present invention is treated with an alkali and bonded to both surfaces of a polarizer produced by immersing and stretching a polyvinyl alcohol film in an iodine solution using a completely saponified polyvinyl alcohol aqueous solution. Instead of alkali treatment, easy adhesion processing as described in JP-A-6-94915 and JP-A-6-118232 may be performed. Further, the surface treatment as described above may be performed.
When the laminate has a form in which an adhesive polymer layer is provided on one side of the cellulose ester resin layer, the laminate surface of the laminate with the polarizer may be on the adhesive polymer layer side, or the cellulose ester resin layer. You may be on the side. From the viewpoint of improving the adhesion between the polarizer and the laminate, it is preferable to directly bond the cellulose ester resin layer side to the polarizer.

The lamination of the laminate of the present invention is preferably bonded to the polarizer so that the transmission axis of the polarizer and the slow axis of the laminate of the present invention are parallel, orthogonal or 45 °. The slow axis can be measured by various conventional methods. For example, a birefringence meter (KOBRADH, manufactured by Oji Scientific Instruments) can be used.
Here, parallel, orthogonal, or 45 ° includes a range of errors allowed in the technical field to which the present invention belongs. For example, it means that it is within a range of ± 10 ° from a strict angle with respect to parallel, orthogonal and 45 °, respectively, and the error from the strict angle is preferably within a range of ± 5 °, and within a range of ± 3 °. Is more preferable.
The parallel of the transmission axis of the polarizer and the slow axis of the laminate of the present invention means that the direction of the main refractive index nx of the laminate of the present invention and the direction of the transmission axis of the polarizer intersect at an angle of ± 10 °. Means that This angle is preferably within a range of ± 5 °, more preferably within a range of ± 3 °, further preferably within a range of ± 1 °, and most preferably within a range of ± 0.5 °.
Further, the orthogonality of the transmission axis of the polarizer and the slow axis of the laminate of the present invention means that the direction of the main refractive index nx of the laminate of the present invention and the direction of the transmission axis of the polarizer are 90 ° ± 10 °. It means that they intersect at an angle within the range of. This angle is preferably in the range of 90 ° ± 5 °, more preferably in the range of 90 ° ± 3 °, even more preferably in the range of 90 ° ± 1 °, most preferably 90 ° ± 0.1 °. Within range. If it is the above ranges, the fall of the polarization degree performance under polarizing plate cross Nicol will be suppressed, and light omission will be reduced and it is preferable.

The polarizing plate is composed of a polarizer and protective films protecting both surfaces thereof, and at least one of the protective films is preferably a laminate of the present invention. Further, usually, a protective film is bonded to one surface of the polarizing plate, and a separate film is bonded to the other surface. The protective film and the separate film are used for the purpose of protecting the polarizing plate at the time of shipping the polarizing plate and at the time of product inspection. In this case, the protect film is bonded for the purpose of protecting the surface of the polarizing plate, and is used on the side opposite to the surface where the polarizing plate is bonded to the liquid crystal plate. Moreover, a separate film is used in order to cover the adhesive layer bonded to a liquid crystal plate, and is used for the surface side which bonds a polarizing plate to a liquid crystal plate.

<Degree of polarization>
In the polarizing plate of the present invention, the degree of polarization is preferably 95.0% or more, more preferably 98.0% or more, and most preferably 99.5% or more.

In the present invention, the degree of polarization of the polarizing plate can be measured using an automatic polarizing film measuring device VAP-7070 manufactured by JASCO Corporation. More specifically, the polarization degree spectrum is calculated from the orthogonal transmittance and the parallel transmittance measured at wavelengths of 380 nm to 700 nm by the following formula, and the weighted average of the light source (auxiliary illuminant C) and the CIE visibility (Y) is calculated. Can be obtained.

Polarization degree (%)
= {(Parallel transmittance−orthogonal transmittance) / (parallel transmittance + orthogonal transmittance)} ^1/2 × 100

<Change in polarization degree>
The polarizing plate of the present invention is excellent in durability under wet heat aging conditions. For this reason, the amount of change in the degree of polarization before and after the polarizing plate durability test described later is small.
The polarizing plate of the present invention measures orthogonal transmittance and parallel transmittance using an automatic polarizing film measuring device VAP-7070 manufactured by JASCO Corporation, and calculates the degree of polarization by the above formula. It is preferable that the amount of change in polarization degree is less than 5% when stored in an environment of 85% humidity for 500 hours.

<Other characteristics>
Other preferable optical characteristics of the polarizing plate of the present invention are described in paragraph Nos. 0238 to 0255 of JP-A-2007-086748, and it is preferable that these characteristics are satisfied.

[Image display device]
The polarizing plate of the present invention is preferably used for an image display device. Examples of such an image display device include a liquid crystal display device and an organic electroluminescence display device. When used for an organic electroluminescence display device, for example, it is used for antireflection applications. Especially, the polarizing plate of this invention is used suitably for a liquid crystal display device.
<Liquid crystal display device>
The liquid crystal display device which is one embodiment as the image display device of the present invention includes a liquid crystal cell and the polarizing plate of the present invention disposed in at least one of the liquid crystal cells.

A preferred embodiment of the liquid crystal display device will be described.
FIG. 2 is a schematic view showing an embodiment of the liquid crystal display device. In FIG. 2, the liquid crystal display device 20 includes a liquid crystal cell having a liquid crystal layer 24 and a liquid crystal cell upper electrode substrate 23 and a liquid crystal cell lower electrode substrate 25 disposed above and below, and upper polarizing plates disposed on both sides of the liquid crystal cell. 21 and the lower polarizing plate 26. A color filter may be disposed between the liquid crystal cell and each polarizing plate. When the liquid crystal display device 20 is used as a transmission type, a cold cathode or hot cathode fluorescent tube, or a backlight having a light emitting diode, field emission element, or electroluminescent element as a light source is disposed on the back surface. The substrate of the liquid crystal cell generally has a thickness of 50 μm to 2 mm.

The upper polarizing plate 21 and the lower polarizing plate 26 usually have a configuration in which a polarizer is sandwiched between two polarizing plate protective films. In the liquid crystal display device 20 of the present invention, it is preferable that at least one polarizing plate is the polarizing plate of the present invention. The polarizing plates 21 and 26 included in the liquid crystal display device 20 of the present invention are the laminate of the present invention as a polarizing plate protective film, a polarizer, and a general transparent protective film in order from the outside of the device (the side far from the liquid crystal cell). A form in which each layer is laminated in order is preferable. Moreover, it replaces with the said general transparent protective film, and the form which used the laminated board of this invention as a phase difference film is also preferable.
The substrate of the liquid crystal cell generally has a thickness of 50 μm to 2 mm.

(Types of liquid crystal display devices)
The cellulose ester film of the present invention can be used for liquid crystal cells in various display modes. TN (Twisted Nematic), IPS (In-Plane Switching), FLC (Ferroelectric Liquid Crystal), AFLC (Anti-Frequency Liquid Crystal), OCB (Optically Charged Compensated). Various display modes have been proposed, such as Electrically Controlled Birefringence (HAN) and Hybrid Aligned Nematic (HAN). In addition, a display mode in which the above display mode is oriented and divided has been proposed. The cellulose ester of the present invention can be suitably used for a liquid crystal display device in any display mode. Further, it can be suitably used for any liquid crystal display device of a transmissive type, a reflective type, and a transflective type.

The present invention will be described in more detail based on examples, but the present invention is not limited to the following examples.

[Synthesis example]
<Synthesis Example 1: Synthesis of Polymer P-1>
In a 1 L three-necked flask equipped with a thermometer, stirring blades, and reflux ring, 75.0 g of methyl ethyl ketone was charged and stirred at 85 ° C. under a nitrogen stream. Separately, in a 300 mL Erlenmeyer flask, 131.1 g of methyl methacrylate (monomer leading to the repeating unit A-1 exemplified above), 18.9 g of 2-hydroxyethyl methacrylate (monomer leading to the repeating unit B-1 exemplified above), dimethyl A monomer composition was prepared by measuring 0.08 g of 2,2′-azobisisobutyrate and 75.0 g of methyl ethyl ketone and mixing and dissolving them.
Next, the monomer composition was dropped into methyl ethyl ketone stirred at 85 ° C. at a rate of 1.2 mL / min. A chemical pump was used for dripping. The reaction solution after completion of the dropwise addition was further reacted at 85 ° C. for 6 hours. After completion of the reaction, the reaction solution was allowed to cool to room temperature, diluted with 500 mL of methyl ethyl ketone, and reprecipitated with 5 L of methanol to obtain a white precipitate. The resulting white precipitate was filtered off, redispersed and washed 3 times with 2 L of methanol, and dried at 60 ° C. overnight to obtain 85.0 g of the target polymer P-1.

<Synthesis Examples 2 to 26: Synthesis of Polymers P-2 to P-26>
In Synthesis Example 1, the monomer type used was changed to a monomer that leads to the repeating unit shown in Table 1 below, and polymers P-2 to P-26 were obtained in the same manner as in Synthesis Example 1.
In Table 1 below, the numbers described in the “Structure” column of the repeating unit correspond to the numbers of the repeating unit exemplified above (the same applies hereinafter).

<Comparative Synthesis Examples 1 and 2: Synthesis of Comparative Polymers HP-1 and HP-2>
In Synthetic Example 1, the monomer species used were changed to monomers that lead to repeating units shown in Table 1 below, and Comparative Polymers HP-1 and HP-2 were obtained in the same manner as in Synthetic Example 1.

Table 1 below shows solubility parameters δt calculated by the Hoy method of the repeating units constituting the polymers obtained in the above synthesis examples and comparative synthesis examples.
Table 1 below also shows the molar amount (mol%) of each repeating unit in the polymers obtained in each of the above synthesis examples and comparative synthesis examples. Here, the mol% of the repeating unit in the polymer was identified by ¹ H NMR measurement using a nuclear magnetic resonance spectrum measuring apparatus (NMR 300 MHz) manufactured by BRUKER.
Table 1 below shows the weight average molecular weights of the polymers obtained in the above synthesis examples and comparative synthesis examples. As the weight average molecular weight of the polymer, a weight average molecular weight measured in terms of polystyrene by gel permeation chromatography (GPC) was adopted. Specific measurement conditions are shown below.
GPC equipment: GPC equipment manufactured by Tosoh Corporation (HLC-8320GPC, Ecosec)
Column: TSK gel SuperHZM-H, TSK gel SuperHZ4000, TSK gel SuperHZ2000 combined use (Tosoh, 4.6 mm ID (inner diameter) x 15.0 cm)
Eluent: Tetrahydrofuran (THF)

[Production Example 1: Production of laminates S-1 to S-30 and HS-1 and HS-2]

<Preparation of Cellulose Ester Resin Layer CA-1>
The following composition was put into a mixing tank, stirred while heating to dissolve each component, and a cellulose acetate solution (dope A) having a solid content concentration of 22% by mass was prepared.
[Composition of Cellulose Acetate Solution (Dope A)]
Cellulose acetate with an acetyl substitution degree of 2.86 100 parts by weight Triphenyl phosphate (plasticizer) 7.8 parts by weight Biphenyl diphenyl phosphate (plasticizer) 3.9 parts by weight Ultraviolet absorber (Tinubin 328 manufactured by Ciba Japan) 0.9 Part by weight Ultraviolet absorber (manufactured by Tinuvin 326 Ciba Japan) 0.2 part by weight Methylene chloride (first solvent) 336 parts by weight Methanol (second solvent) 29 parts by weight 1-butanol (third solvent) 11 parts by weight

Using a band casting apparatus, the prepared dope A was uniformly cast from a casting die onto a stainless steel endless band (casting support) having a width of 2000 mm. When the amount of residual solvent in the dope A reaches 40% by mass, it is peeled off as a polymer film from the casting support, and is conveyed without being actively stretched by a tenter and dried at 130 ° C. in a drying zone. went. The thickness of the obtained cellulose ester resin layer (cellulose ester film) CA-1 was 55 μm.

<Preparation of cellulose ester resin layer CA-2>
Using the band casting apparatus, the prepared dope A was uniformly cast from a casting die onto a stainless steel endless band (casting support) having a width of 2000 mm. When the residual solvent amount in the dope A reaches 40% by mass, the polymer film is peeled from the casting support, and the rotational speed of the downstream roller is made higher than the rotational speed of the upstream roller at the transition portion. Is stretched 1.2 times in the transport direction (MD) at a temperature of 170 ° C. and 1.5 times in the direction perpendicular to the transport direction (TD direction) with a tenter (stretch ratio is 1. 8 times), drying was performed at 130 ° C. in the drying zone. The film thickness of the obtained cellulose ester resin layer (cellulose ester film) CA-2 was 40 μm.

<Creation of cellulose ester resin layer CA-3>
The following composition was put into a mixing tank and stirred while heating to dissolve each component to prepare a cellulose acetate solution (dope B) having a solid content concentration of 22% by mass.
[Composition of cellulose acetate solution (dope B)]
Cellulose acetate with an acetyl substitution degree of 2.87 100 parts by weight Monopet (registered trademark) SB (plasticizer) manufactured by Daiichi Kogyo Kagaku Co. 9.0 parts by weight SAIB-100 (plasticizer) manufactured by Eastman Chemical Co. 3.0 Part by mass Ultraviolet absorber (UV-1) 2.0 parts by mass Methylene chloride (first solvent) 297.7 parts by mass Methanol (second solvent) 75.4 parts by mass 1-butanol (third solvent) 3.8 parts by mass Part

Using a band casting apparatus, the prepared dope B was uniformly cast from a casting die onto a stainless steel endless band (casting support) having a width of 2000 mm. When the amount of residual solvent in the dope B reaches 40% by mass, it is peeled off as a polymer film from the casting support, transported without being actively stretched by a tenter, and dried at 130 ° C. in a drying zone. went. The thickness of the obtained cellulose ester resin layer (cellulose ester film) CA-3 was 55 μm.

<Creation of cellulose ester resin layer CA-4>
The following composition was put into a mixing tank and stirred while heating to dissolve each component to prepare a cellulose acetate solution (dope C) having a solid content concentration of 22% by mass.
[Composition of cellulose acetate solution (Dope C)]
Cellulose acetate with an acetyl substitution degree of 2.87 100 parts by weight Polycondensation polymer (A) (plasticizer) 12.0 parts by weight UV absorber (UV-1) 2.0 parts by weight Methylene chloride (first solvent) 297.7 Part by mass Methanol (second solvent) 75.4 parts by mass 1-butanol (third solvent) 3.8 parts by mass

Polycondensation polymer (A): Polyester composed of adipic acid and ethanediol (terminal is a hydroxy group) (number average molecular weight = 1000)

Using a band casting apparatus, the prepared dope C was uniformly cast from a casting die onto a stainless steel endless band (casting support) having a width of 2000 mm. When the amount of residual solvent in the dope C reaches 40% by mass, it is peeled off as a polymer film from the casting support, and conveyed without being actively stretched by a tenter and dried at 130 ° C. in a drying zone. went. The obtained cellulose ester resin layer (cellulose ester film) CA-4 had a thickness of 55 μm.

<Creation of cellulose ester resin layer CA-5>
In the production of the cellulose ester resin layer CA-3, the cellulose ester resin layer (cellulose ester film) CA-5 of the present invention was 55 μm thick except that 4.0 parts by mass of the following compound (1) was added. Got in.

Compound (1) is a barbituric acid compound (Exemplary Compound A-3) described in International Publication No. 2015/005398, and was synthesized by the method described in the publication.

<Preparation of laminate S-1>
The polymer P-1 was mixed with methyl ethyl ketone so as to have a solid content of 15%, charged into a glass separable flask equipped with a stirrer, stirred at room temperature for 5 hours, and filtered through a polypropylene depth filter having a pore size of 5 μm. A composition for forming an adhesive polymer was obtained. Next, the above-mentioned composition for forming an adhesive polymer was applied on the cellulose ester resin layer CA-1 produced by the above-described procedure using a gravure coater. Subsequently, it was dried at 25 ° C. for 1 minute and further dried at 120 ° C. for about 5 minutes to obtain a laminate S-1 having a film thickness of 60 μm.

<Production of Laminates S-2 to S-30 and Comparative Laminates HS-1 and HS-2>
In <Preparation of Laminate S-1>, the polymer P-1 used in the adhesive polymer forming composition was changed as shown in Table 2 below, and the cellulose ester resin layer was changed as shown in Table 2 below. Except for the above, laminates S-2 to S-30 and comparative laminates HS-1 and HS-2 were produced in the same manner as in <Preparation of laminate S-1> above. Each of the obtained laminates had a thickness of 60 μm.

[Test Example 1: Interlayer adhesion test of laminate]
For the interlaminar adhesion of the laminate, a cross cut test according to JIS K 5400 was applied. The specific procedure is shown below.
Using the cutter knife and the cutter guide, 11 cuts with an interval of 1 mm were made on the surface on the adhesive polymer layer side of each laminate prepared above to produce 100 grids. After the cellophane tape was strongly pressure-bonded on the grid, the end of the tape was peeled off at an angle of 45 °, and the state of the grid (the state of peeling of the lattice constituting the grid) was observed. The observation results were applied to the following evaluation criteria to evaluate the adhesion.

A: The eyes of any lattice do not peel off.
B: Peeling of the lattice is less than 5%.
C: The lattice peeling is 5% or more and less than 30%.
D: The peeling of the lattice is 30% or more.
The results are shown in Table 2 below.

[Test Example 2: Evaluation of moisture permeability of laminated body (moisture permeability at 40 ° C. and 90% relative humidity)]
For moisture permeability, we applied “Measurement of vapor transmission (mass method, thermometer method, vapor pressure method, adsorption amount method)” on pages 285 to 294 of “Polymer Properties II” (Polymer Experiment Course 4, Kyoritsu Shuppan). ,evaluated. The specific procedure is shown below.
According to the method of JIS Z-0208, each of the laminates produced above was cut, and the cut laminate was attached to a moisture permeable cup to obtain a test sample. This test sample was conditioned for 24 hours under conditions of a temperature of 40 ° C. and a relative humidity of 90%.
The weight of the test sample before and after humidity conditioning is weighed, the mass of the test sample before humidity conditioning is A, and the mass of the sample after tempering is B. Calculated.
Δm = AB
Subsequently, the above Δm was converted to a value per 1 m ² of the sample area and used as moisture permeability (g / m ² / day). The moisture permeability of each obtained laminate was evaluated according to the following evaluation criteria.

A +: The moisture permeability is less than 250 g / m ² / day.
A: The moisture permeability is 250 g / m ² / day or more and less than 500 g.
B: The moisture permeability is 500 g / m ² / day or more and less than 1000 g / m ² / day.
C: moisture permeability is less than 1000g ^/ m 2 ^/ day or more 1600g ^/ m 2 ^/ day.
D: The water vapor transmission rate is 1600 g / m ² / day or more.
The results are shown in Table 2 below.

As shown in Table 2, the laminate HS-1 having a layer of polymer having the repeating unit of [a] defined in the present invention but not having the repeating unit of [b] on the cellulose ester resin layer, The result was inferior in interlayer adhesion (Comparative Example 1). On the contrary, the laminate HS-2 in which a polymer layer having the repeating unit [b] defined in the present invention but not having the repeating unit [a] is provided on the cellulose ester resin layer has an adhesiveness between the layers. However, the moisture permeability was high and the moisture barrier action was poor (Comparative Example 2).
On the other hand, the laminates S-1 to S-30 including the adhesive polymer layer having both the repeating unit [a] and the repeating unit [b] defined in the present invention have improved adhesion between layers. The results were excellent, and the moisture permeability was low and the moisture barrier action was excellent (Examples 1 to 30).

[Production Example 2: Production of polarizing plates PL-1 to PL-3, PL-5 to PL-7 and comparative polarizing plates HPL-1 and HPL-2]
As described below, polarizing plates PL-1 to PL-3, PL-5 to PL-7, and comparative polarizing plates HPL-1 and HPL-2 were prepared.
(1) Saponification Commercially available cellulose acylate film (Fujitack ZRD40, manufactured by FUJIFILM Corporation) and each of the laminates S-1, S-6, S-7, S-28, S-29 prepared above, After immersing S-30, HS-1 and HS-2 in a 1.5 mol / L NaOH aqueous solution (saponification solution) maintained at 55 ° C. for 2 minutes, the ZRD 40 and each laminate were washed with water. Next, after immersing ZRD40 and each laminate in a 0.05 mol / L sulfuric acid aqueous solution at 25 ° C. for 30 seconds, they are further washed for 30 seconds under running water to bring ZRD40 and each laminate to a neutral state. did. The obtained ZRD40 and each laminate were repeatedly drained with an air knife three times, and after dropping water, they were retained in a drying zone at 70 ° C. for 15 seconds and dried to obtain a saponified ZRD40 and each laminate.

(2) Production of Polarizer According to Example 1 of Japanese Patent Application Laid-Open No. 2001-141926, iodine was adsorbed to a stretched polyvinyl alcohol film to produce a polarizer having a thickness of 27 μm.

(3) Bonding Each laminate after the above saponification (arranged so that the adhesive polymer layer of each laminate is not laminated (that is, the cellulose ester resin layer surface is in contact with the polarizer)), produced above The polarizer and the cellulose acylate film ZRD40 after saponification are bonded in this order with a PVA adhesive, and thermally dried to obtain polarizing plates PL-1 to PL-3 and PL-5 to PL-. 7 and comparative polarizing plates HPL-1 and HPL-2 were prepared.
Under the present circumstances, it arrange | positioned so that the longitudinal direction of the roll of the produced polarizer and the longitudinal direction of the roll of the cellulose-ester resin layer of each laminated body may become parallel. Moreover, it arrange | positioned so that the longitudinal direction of the roll of a polarizer and the longitudinal direction of the roll of the said cell roll acylate film ZRD40 may become parallel.

[Production Example 3: Production of polarizing plates PL-4 and PL-8 to PL-10]
Polarizer plates PL-4 and PL-8 to PL-10 were produced as follows.

(1) Preparation of active energy ray hardening-type adhesive composition Each component was mixed with the composition shown below, and it stirred at 50 degreeC for 1 hour, and obtained the active energy ray hardening-type adhesive composition.
――――――――――――――――――――――――――――――――――
Composition of active energy ray-curable adhesive composition ――――――――――――――――――――――――――――――――――
Radical polymerizable compound: Aronix M-220 manufactured by Toa Gosei Co., Ltd.
20.0 parts by mass Njin-Hydroxyacrylamide 40.0 parts by mass Acroyl morpholine 40.0 parts by mass Radical polymerization initiator: KAYACURE DETX-S manufactured by Nippon Kayaku Co., Ltd.
0.5 part by mass radical polymerization initiator: IRGACURE907 manufactured by BASF
1.5 parts by mass ――――――――――――――――――――――――――――――――――

The laminates S-8 and S-28 to S-30 produced above were subjected to corona treatment on the adhesive polymer layer side. On the surface subjected to the corona treatment, the active energy ray-curable adhesive composition prepared above was applied to an MCD coater (manufactured by Fuji Machine Co., Ltd., cell shape: honeycomb, number of gravure roll wires: 1000 / INCH, rotation speed 140% The film was applied so as to have a thickness of 0.5 μm.
Separately, a cycloolefin film having a thickness of 40 μm (Arton G7810 manufactured by JSR) was prepared, and the surface thereof was subjected to corona treatment. The active energy ray-curable adhesive composition was applied to the corona-treated surface so as to have a thickness of 0.5 μm in the same manner as described above.
Subsequently, the surface on which the active energy ray-curable adhesive composition of laminates S-8 and S-28 to S-30 was applied, and the surface on which the active energy ray-curable adhesive composition of the cycloolefin film was applied Were bonded to both sides of the polarizer prepared above to prepare a polarizing plate precursor. Then, it heated at 50 degreeC using IR heater from both surfaces of this polarizing plate precursor. Subsequently, the active energy ray shown below was irradiated to both surfaces of the polarizing plate precursor, and the said active energy ray hardening-type adhesive composition was hardened. Thereafter, it was dried with hot air at 70 ° C. for 3 minutes to obtain polarizing plates PL-4 and PL-8 to PL-10.

(Active energy rays)
As active energy rays, ultraviolet rays (gallium filled metal halide lamp), irradiation apparatus: Fusion UV Systems, Inc. Light HAMMER10, bulb: V bulb, peak illuminance: 1600 mW / cm ² , integrated irradiation amount 1000 / mJ / cm ² (wavelength) 380-440 nm) was used. The illuminance of ultraviolet rays was measured using a Sola-Check system manufactured by Solatell.

[Test Example 3: Evaluation of polarizer durability of polarizing plate]
The durability of the polarizing plate was measured by measuring the orthogonal transmittance and the polarization degree in the following manner in a form in which the polarizing plate was attached to glass through an adhesive.
A polarizing plate is placed on a glass plate, and the laminates S-1, S-6, S-7, S-8, S-28, S-29, S-30, HS-1 and HS-2 are air interfaces. Two samples (about 5 cm × 5 cm) pasted so as to be on the side (on the side away from the glass plate) were prepared. About these samples, the glass plate side was set toward the light source, and the degree of polarization was measured. Each of the two samples was measured and the arithmetic average value was taken as the polarization degree of the polarizing plate.
The degree of polarization was calculated by the following formula.

Polarization degree (%) = [(parallel transmittance−orthogonal transmittance) / (orthogonal transmittance + parallel transmittance)] ^1/2 × 100

The degree of polarization was measured in the range of 380 nm to 780 nm using an automatic polarizing film measuring device VAP-7070 manufactured by JASCO Corporation, and the measured value at a wavelength of 410 nm at which the degree of deterioration is more noticeable than other wavelengths was adopted. .
Thereafter, it was stored for 500 hours in an environment of a temperature of 85 ° C. and a relative humidity of 85%. Subsequently, the polarization degree was measured about two samples like the above, the measured value of two samples was arithmetically averaged, and it was set as the polarization degree of the polarizing plate after a preservation | save. Based on the amount of change in the degree of polarization before and after storage, the polarizing plate durability was evaluated based on the following evaluation criteria.
Here, the amount of change in polarization degree is calculated by the following equation.

Polarization degree change (%) = [Polarization degree after storage (%) − Polarization degree before storage (%)]

<Polarizer durability evaluation criteria>
Polarization degree change (%)
A +: Polarization degree change amount is less than 0.05% A: Polarization degree change amount is 0.05% or more and less than 2.0% B: Polarization degree change amount is 2.0% or more and less than 3.0% C: Polarization degree Change amount is 3.0% or more and less than 5.0% D: Polarization degree change amount is 5.0% or more The results are shown in Table 3 below.

As described in Table 3 above, the comparative polarizing plate HPL-1 using the comparative laminate HS-1 as a protective film has a poor interlayer adhesion of the protective film, and the cellulose ester resin layer and the polymer layer are peeled off. A polarizing plate capable of evaluating durability could not be obtained (Comparative Example 3).
In addition, the comparative polarizing plate HPL-2 using the comparative laminate HS-2 as a protective film resulted in greatly inferior polarizer durability (Comparative Example 4).
In contrast, the polarizing plates PL-1 to PL-10 of the present invention using the laminate of the present invention as a protective film showed excellent polarizer durability. That is, by incorporating a polarizing plate using the laminate of the present invention as a protective film for a polarizer into an image display device, deterioration in image quality can be effectively suppressed even when used for a long time under high temperature and high humidity conditions. Recognize.

While this invention has been described in conjunction with its embodiments, we do not intend to limit our invention in any detail of the description unless otherwise specified and are contrary to the spirit and scope of the invention as set forth in the appended claims. I think it should be interpreted widely.

This application claims priority based on Japanese Patent Application No. 2015-195324 filed in Japan on September 30, 2015 and Japanese Patent Application No. 2016-016705 filed on January 29, 2016 in Japan. All of which are hereby incorporated herein by reference as if fully set forth herein.

10 Laminate (laminate)
DESCRIPTION OF SYMBOLS 11 Cellulose ester resin layer 12 Adhesive polymer layer 20 Liquid crystal display device 21 Upper polarizing plate 22 Upper polarizing plate absorption axis direction 23 Liquid crystal cell upper electrode substrate 24 Liquid crystal layer 25 Liquid crystal cell lower electrode substrate 26 Lower polarizing plate 27 Lower polarization Direction of plate absorption axis

Claims

It has a cellulose ester resin layer and an adhesive polymer layer provided directly on the cellulose ester resin layer, and the adhesive polymer constituting the adhesive polymer layer is at least one repeating unit of the following [a]: The laminated body which has at least 1 sort (s) of the repeating unit of following [b].
[A]:
A repeating unit derived from a (meth) acrylic ester compound, an olefin compound, a vinylidene compound or a cyclic olefin compound and having a solubility parameter δt calculated by the Hoy method of 13.5 to 19.5.
[B]:
(Meth) acrylic acid ester compounds, (meth) acrylic acid compounds, (meth) acrylamide compounds, vinyl acetate compounds, vinyl ketone compounds, maleic anhydride compounds or repeating units derived from styrene compounds or ethylenically unsaturated other than these repeating units A repeating unit derived from a compound having a bond and having a solubility parameter δt calculated by the Hoy method of 20.0 to 26.0.
The laminate according to claim 1, wherein the adhesive polymer has a repeating unit represented by the following general formula 1 as the repeating unit [b].
General formula 1:

In general formula 1,
R 1 represents a hydrogen atom or an alkyl group.
R 2 and R 3 represent a hydrogen atom, an alkyl group, an aryl group or an alkoxycarbonyl group.
L is a single bond, or a divalent linking group selected from an alkylene group, an arylene group, —C (═O) —, —O— and —N (R 4 ) —, or 2 of these linking groups. A divalent linking group formed by combining more than one species is shown.
R 4 represents a hydrogen atom or an alkyl group.
The laminate according to claim 1 or 2, wherein the adhesive polymer has a repeating unit represented by the following general formula 2 as the repeating unit of [a].
General formula 2:

In general formula 2,
R 5 represents a hydrogen atom or an alkyl group.
R 6 and R 7 represent a hydrogen atom, an alkyl group, an aryl group or an alkoxycarbonyl group.
R 8 represents an alkyl group having 1 to 20 carbon atoms or a cycloalkyl group having 3 to 10 carbon atoms.
The molar amount of the repeating unit (b) occupying in the total molar amount of the monomer component constituting the adhesive polymer is 5 mol% or more and 90 mol% or less, according to any one of claims 1 to 3. Laminated body.
The laminate according to any one of claims 1 to 4, wherein the adhesive polymer has a repeating unit represented by the following general formula 1-1 as the repeating unit [b].
Formula 1-1:

In the Formula 1-1, R 1 and L are respectively the same meanings as R 1 and L in the above general formula 1.
The laminate according to any one of claims 1 to 5, wherein the adhesive polymer has a repeating unit represented by the following general formula 2-2 as the repeating unit of [a].
Formula 2-2

In the Formula 2-2, R 5 and R 8 are the same meanings as R 5 and R 8 in the general formula 2.
The laminate according to any one of claims 1 to 6, wherein the cellulose ester constituting the cellulose ester resin layer is cellulose acylate.
A polarizing plate comprising the laminate according to any one of claims 1 to 7 and a polarizer.
An image display device having the polarizing plate according to claim 8.