阅读说明：本技术 偏光膜及其制造方法 (Polarizing film and method for producing same ) 是由 太田阳介 于 2019-09-19 设计创作，主要内容包括：偏光膜,其为依次层叠有第1树脂层、偏光片、取向膜、第2树脂层的偏光膜,第1树脂层为包含(甲基)丙烯酸系化合物的第1固化性组合物的固化物,偏光片为偏光片形成用组合物的固化物,所述偏光片形成用组合物包含具有(甲基)丙烯酰基的聚合性液晶化合物和二向色性色素,取向膜为包含(甲基)丙烯酸系化合物的取向膜形成用组合物的固化物,第2树脂层为包含(甲基)丙烯酸系化合物的第2固化性组合物的固化物,第1固化性组合物及第2固化性组合物中的至少一者包含每单位分子量的(甲基)丙烯酰基数为40×10～(-4)以下的氨基甲酸酯(甲基)丙烯酸酯化合物作为(甲基)丙烯酸系化合物。(A polarizing film in which a1 st resin layer, a polarizing plate, an alignment film, and a 2 nd resin layer are sequentially laminated, wherein the 1 st resin layer is a cured product of a1 st curable composition containing a (meth) acrylic compound, and the polarizing plate is a cured product of a composition for forming a polarizing plate containing a polymerizable liquid crystal compound having a (meth) acryloyl group and a polymerizable liquid crystal compound having a (meth) acryloyl groupA dichroic dye, wherein the alignment film is a cured product of a composition for forming an alignment film comprising a (meth) acrylic compound, the 2 nd resin layer is a cured product of a 2 nd curable composition comprising a (meth) acrylic compound, and at least one of the 1 st curable composition and the 2 nd curable composition contains a (meth) acryloyl group having a number of 40 x 10 per unit molecular weight ‑4 The following urethane (meth) acrylate compounds are used as the (meth) acrylic compounds.)

1. A polarizing film comprising a1 st resin layer, a polarizer, an alignment film, and a 2 nd resin layer laminated in this order,

the 1 st resin layer is a cured product of a1 st curable composition containing a (meth) acrylic compound,

the polarizer is a cured product of a composition for forming a polarizer, the composition for forming a polarizer comprising a polymerizable liquid crystal compound having a (meth) acryloyl group and a dichroic dye,

the alignment film is a cured product of an alignment film-forming composition containing a (meth) acrylic compound,

the 2 nd resin layer is a cured product of a 2 nd curable composition containing a (meth) acrylic compound,

at least one of the 1 st curable composition and the 2 nd curable composition contains a number of (meth) acryloyl groups per unit molecular weight of 40X 10^-4The following urethane (meth) acrylate compounds are used as the (meth) acrylic compounds.

2. The polarizing film according to claim 1, wherein at least one of the 1 st curable composition and the 2 nd curable composition further comprises a polyfunctional (meth) acrylate compound as the (meth) acrylic compound.

3. The polarizing film according to claim 2, wherein the number of (meth) acryloyl groups of the polyfunctional (meth) acrylate compound is 6 or less.

4. The polarizing film according to claim 2 or 3, wherein the polyfunctional (meth) acrylate compound has a branched structure, and the number of atoms of a chain connecting a branch point closest to the (meth) acryloyl group in the branched structure to the (meth) acryloyl group is 2 or more.

5. A method of producing the polarizing film according to any one of claims 1 to 4, comprising the steps of:

a1 st curable composition is applied or laminated on a polarizer surface of a laminate in which a 2 nd resin layer, an alignment film, and a polarizer are laminated in this order, and the 1 st curable composition is cured.

6. A method of producing the polarizing film according to any one of claims 1 to 4, comprising the steps of:

a laminate comprising a release film, a1 st resin layer, a polarizer, an alignment film, and a 2 nd resin layer laminated in this order is obtained by laminating the 1 st curable composition formed on the release film with the polarizer surface of a laminate comprising the 2 nd resin layer, the alignment film, and the polarizer laminated in this order, and irradiating the release film side with an active energy ray to cure the 1 st curable composition, and the release film is peeled from the laminate.

Technical Field

The present invention relates to a polarizing film and a method for producing the same.

Background

A polarizing film or the like is used for a Flat Panel Display (FPD). As such a polarizing film, there are known: a polarizing film obtained by bonding a polarizing plate, which is obtained by orientation-adsorbing a dichroic pigment such as iodine in a polyvinyl alcohol resin film, to a base material; a polarizing film obtained by applying a polymerizable liquid crystal compound to a substrate and polymerizing the compound. For example, patent document 1 discloses a polarizing film having a dye diffusion preventing layer on both surfaces of a polarizer containing a polymer of a polymerizable liquid crystal compound and a dichroic dye.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2017-083843

Disclosure of Invention

Problems to be solved by the invention

The purpose of the present invention is to provide a polarizing film having excellent interlayer adhesiveness and a method for producing the same.

Means for solving the problems

The present inventors have intensively studied to solve the above-mentioned problems, and as a result, they have found that, in a polarizing film in which a1 st resin layer, a polarizer, an alignment film, and a 2 nd resin layer are sequentially laminated, the 1 st resin layer, the polarizer, the alignment film, and the 2 nd resin layer are each a cured product of a composition containing a compound having a (meth) acryloyl group, and at least one of a1 st curable composition and a 2 nd curable composition contains a compound having a (meth) acryloyl group number of 40 × 10 per unit molecular weight^-4The following urethane (meth) acrylate compounds can solve the above problems as (meth) acrylic compounds, and the present invention has been completed. That is, the present invention includes the following aspects.

[1] A polarizing film comprising a1 st resin layer, a polarizer, an alignment film, and a 2 nd resin layer laminated in this order,

the 1 st resin layer is a cured product of a1 st curable composition containing a (meth) acrylic compound,

the polarizer is a cured product of a composition for forming a polarizer, the composition for forming a polarizer comprising a polymerizable liquid crystal compound having a (meth) acryloyl group and a dichroic dye,

the alignment film is a cured product of an alignment film-forming composition containing a (meth) acrylic compound,

the 2 nd resin layer is a cured product of a 2 nd curable composition containing a (meth) acrylic compound,

at least one of the 1 st curable composition and the 2 nd curable composition contains a number of (meth) acryloyl groups per unit molecular weight of 40X 10^-4The following urethane (meth) acrylate compounds are used as the (meth) acrylic compounds.

[2] The polarizing film according to [1], wherein at least one of the 1 st curable composition and the 2 nd curable composition further comprises a polyfunctional (meth) acrylate compound as a (meth) acrylic compound.

[3] The polarizing film according to [2], wherein the number of (meth) acryloyl groups of the polyfunctional (meth) acrylate compound is 6 or less.

[4] The polarizing film according to [2] or [3], wherein the polyfunctional (meth) acrylate compound has a branched structure, and the number of atoms of a chain connecting a branch point closest to the (meth) acryloyl group in the branched structure to the (meth) acryloyl group is 2 or more.

[5] A method for producing a polarizing film according to any one of [1] to [4], comprising the steps of: a1 st curable composition is applied or laminated on a polarizer surface of a laminate in which a 2 nd resin layer, an alignment film, and a polarizer are laminated in this order, and the 1 st curable composition is cured.

[6] A method for producing a polarizing film according to any one of [1] to [4], comprising the steps of: a laminate comprising a release film, a1 st resin layer, a polarizer, an alignment film, and a 2 nd resin layer laminated in this order is obtained by laminating the 1 st curable composition formed on the release film with the polarizer surface of a laminate comprising the 2 nd resin layer, the alignment film, and the polarizer laminated in this order, and irradiating the release film side with an active energy ray to cure the 1 st curable composition, and the release film is peeled from the laminate.

ADVANTAGEOUS EFFECTS OF INVENTION

The polarizing film of the present invention has excellent interlayer adhesiveness.

Drawings

Fig. 1 is a schematic cross-sectional view of a layer structure of a front-panel-attached polarizing film on which a polarizing film as one embodiment of the present invention is laminated.

Fig. 2 is a schematic cross-sectional view of a layer structure of a front-panel-attached polarizing plate on which a polarizing film as one embodiment of the present invention is laminated.

Fig. 3 is a schematic cross-sectional view of a layer structure of a front-panel-attached polarizing film in which a polarizing film as one embodiment of the present invention is laminated.

Fig. 4 is a schematic cross-sectional view of a layer structure of a front-panel-attached polarizing plate on which a polarizing film as one embodiment of the present invention is laminated.

Detailed Description

[ polarizing film ]

The polarizing film of the present invention is laminated with a1 st resin layer, a polarizer, an alignment film, and a 2 nd resin layer in this order.

The 1 st resin layer is a cured product of a1 st curable composition containing a (meth) acrylic compound, the polarizer is a cured product of a composition for forming a polarizer, the composition comprising a polymerizable liquid crystal compound having a (meth) acryloyl group and a dichroic pigment, the alignment film is a cured product of a composition for forming an alignment film, the composition comprising a (meth) acrylic compound, and the 2 nd resin layer is a cured product of a 2 nd curable composition, the composition comprising a (meth) acrylic compound.

In this way, in the polarizing film of the present invention, each layer is constituted by a cured product of a composition containing a compound having a (meth) acryloyl group, that is, each layer is constituted by a polymer containing a compound having a (meth) acryloyl group, and therefore, the compatibility of the interfaces of each layer is high, and excellent interlayer adhesiveness can be exhibited.

In the polarizing film of the present invention, at least one of the 1 st curable composition for forming the 1 st resin layer and the 2 nd curable composition for forming the 2 nd resin layer contains (meth) acryloyl groups in an amount of 40 × 10 per unit molecular weight^-4The following urethane (meth) acrylate compound can also have excellent flexibility because it is a (meth) acrylic compound. Therefore, the polarizing film of the present invention can achieve both excellent adhesiveness and bendability.

< polarizing plate >

The polarizer included in the polarizing film of the present invention is formed on the surface of the alignment film opposite to the 2 nd resin layer. The polarizer is a cured product of a composition for forming a polarizer, which contains a polymerizable liquid crystal compound having a (meth) acryloyl group and a dichroic dye. In such a polarizer, polymerization and curing are performed in a state where the dichroic dye is encapsulated by the polymerizable liquid crystal compound and the dichroic dye are aligned, but when exposed to a high-temperature environment, there is a tendency that: the dichroic dye is thermally diffused from the polarizer to the 1 st resin layer or the 2 nd resin layer, and thus deterioration of the polarizing performance with time is likely to occur. In a preferred embodiment of the present invention, the 1 st resin layer and the 2 nd resin layer are each composed of a cured product of a curable composition containing a specific (meth) acrylic compound, and therefore, a crosslinked structure capable of suppressing diffusion of a dichroic dye can be formed, and a decrease in polarizing performance can be effectively suppressed in some cases. In the present specification, the term "heat resistance" means a property that can suppress a decrease in polarization performance (for example, a change in polarization degree, transmittance, and the like) even when exposed to a high-temperature environment for a long time, and the term "heat resistance" is increased or improved means that a decrease or a change in polarization performance due to a high temperature is less.

In the polarizing film of the present invention, the polymerizable liquid crystal compound (hereinafter, sometimes referred to as "polymerizable liquid crystal compound (a)") contained in the composition for forming a polarizer is a liquid crystal compound having at least one (meth) acryloyl group, and a liquid crystal compound having two or more (meth) acryloyl groups is preferable from the viewpoint of improving the adhesiveness, bendability, and heat resistance of the polarizing film. The polymerizable liquid crystal compound (a) may contain a polymerizable group other than a (meth) acryloyl group. The polymerizable group refers to a group capable of participating in a polymerization reaction by an active radical, an acid, or the like generated from a polymerization initiator. Examples of the polymerizable group other than the (meth) acryloyl group include a vinyl group, a vinyloxy group, a 1-chloroethenyl group, an isopropenyl group, a 4-vinylphenyl group, an oxirane group, and an oxetanyl group. In the present invention, the polymerizable group of the polymerizable liquid crystal compound (a) is preferably composed of a (meth) acryloyl group, and more preferably composed of a (meth) acryloyloxy group, from the viewpoint of adhesiveness, bendability, and heat resistance of the polarizing film.

In the present invention, the polymerizable liquid crystal compound (a) is preferably a compound exhibiting smectic liquid crystallinity. By using a polymerizable liquid crystal compound exhibiting smectic liquid crystallinity, a polarizer having a high degree of alignment order can be formed. The liquid crystal state exhibited by the polymerizable liquid crystal compound (a) is a smectic phase (smectic liquid crystal state), and a higher order smectic phase (higher order smectic liquid crystal state) is more preferable from the viewpoint of enabling a higher degree of alignment order. Here, the higher order smectic phase means smectic B phase, smectic D phase, smectic E phase, smectic F phase, smectic G phase, smectic H phase, smectic I phase, smectic J phase, smectic K phase and smectic L phase, and among these, smectic B phase, smectic F phase and smectic I phase are more preferable. The liquid crystal may be a thermotropic liquid crystal or a lyotropic liquid crystal, and is preferably thermotropic liquid crystal in view of enabling precise film thickness control. The polymerizable liquid crystal compound (a) may be a monomer, or an oligomer or polymer obtained by polymerizing a polymerizable group.

The polymerizable liquid crystal compound (a) is not particularly limited as long as it is a liquid crystal compound having at least one (meth) acryloyl group, and known polymerizable liquid crystal compounds, preferably compounds exhibiting smectic liquid crystallinity, can be used. Examples of such a polymerizable liquid crystal compound include a compound represented by the following formula (a1) (hereinafter, may be referred to as "polymerizable liquid crystal compound (a 1)").

U¹-V¹-W¹-(X¹-Y¹-)_n-X²-W²-V²-U² (A1)

[ in the formula (A1),

X¹and X²Independently represents a divalent aromatic group or a divalent alicyclic hydrocarbon group, wherein a hydrogen atom contained in the divalent aromatic group or the divalent alicyclic hydrocarbon group may be substituted with a halogen atom, an alkyl group having 1 to 4 carbon atoms, a fluoroalkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a cyano group, or a nitro group, and a carbon atom constituting the divalent aromatic group or the divalent alicyclic hydrocarbon group may be substituted with an oxygen atom, a sulfur atom, or a nitrogen atom. Wherein, X¹And X²At least 1 of them is a1, 4-phenylene group which may have a substituent or a cyclohexane-1, 4-diyl group which may have a substituent.

Y¹Is a single bond or a divalent linking group.

n is 1 to 3, and when n is 2 or more, a plurality of X¹May be the same or different from each other. X²Can be associated with a plurality of X¹Either or both of which may be the same or different. When n is 2 or more, plural Y' s¹May be the same or different from each other. From the viewpoint of liquid crystallinity, n is preferably 2 or more.

U¹Represents a hydrogen atom or a (meth) acryloyloxy group.

U²Represents a (meth) acryloyloxy group.

W¹And W²Independently of one another, a single bond or a divalent linking group.

V¹And V²Independently represent optionally substituted alkanediyl having 1 to 20 carbon atoms, -CH constituting the alkanediyl₂-may be replaced by-O-, -CO-, -S-or NH-.]

Polymerizable liquid crystalIn the compound (A1), X¹And X²Preferred are, independently of one another, a1, 4-phenylene group which may have a substituent, or a cyclohexane-1, 4-diyl group which may have a substituent, X¹And X²At least 1 of them is a1, 4-phenylene group which may have a substituent, or a cyclohexane-1, 4-diyl group which may have a substituent, preferably a trans-cyclohexane-1, 4-diyl group. Examples of the substituent optionally contained in the optionally substituted 1, 4-phenylene group or the optionally substituted cyclohexane-1, 4-diyl group include an alkyl group having 1 to 4 carbon atoms such as a methyl group, an ethyl group, a butyl group and the like, a cyano group, a halogen atom such as a chlorine atom, a fluorine atom and the like. Preferably unsubstituted.

Further, the polymerizable liquid crystal compound (A1) is preferably a moiety represented by the formula (A1-1) in the formula (A1) [ hereinafter referred to as a partial structure (A1-1) ] from the viewpoint of easily exhibiting smectic liquid crystallinity. The (c) is an asymmetric structure.

-(X¹-Y¹-)_n-X²- (A1-1)

[ in the formula, X¹、Y¹、X²And n each represents the same meaning as described above. Angle (c)

Examples of the polymerizable liquid crystal compound (a1) having an asymmetric partial structure (a1-1) include: n is 1 and 1X¹And X²Polymerizable liquid crystal compounds (A1) having different structures from each other. In addition, there may be mentioned: a polymerizable liquid crystal compound (A1) wherein n is 2 and 2Y s¹A compound of the same structure as each other which is 2X¹Are of the same structure as each other and are 1X²With the above 2X¹A different structure; a polymerizable liquid crystal compound (A1) wherein n is 2 and 2Y s¹A compound of the same structure as each other which is 2X¹Is bonded to W¹X of (2)¹With another X¹And X²A different structure, and is another X¹And X²The same structure as each other. Further, there may be mentioned: a polymerizable liquid crystal compound (A1) wherein n is 3 and 3Y s¹A compound of the same structure as each other which is 3X¹And 1X²Any one of them has a structure different from that of the other 3.

Y¹Is preferably-CH₂CH₂-、-CH₂O-、-CH₂CH₂O-, -COO-, -OCOO-, single bond, -N ═ N-, -CR^a＝CR^b-、-C≡C-、-CR^aN-or-CO-NR^a-。R^aAnd R^bIndependently represent a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. Y is¹More preferably-CH₂CH₂-, -COO-or single bonds, in the presence of a plurality of Y¹In the case of (2), with X²Bonded Y¹More preferably-CH₂CH₂-or-CH₂O-is formed. At X¹And X²When all of the Y atoms have the same structure, it is preferable that 2 or more Y atoms different from each other in bonding form are present¹. In the presence of a plurality of Y's different in bonding mode from each other¹In the case of (b), the structure is asymmetric, and thus smectic liquid crystallinity tends to be easily exhibited.

U²Is a (meth) acryloyloxy group. U shape¹Is a hydrogen atom or a (meth) acryloyloxy group, preferably a (meth) acryloyloxy group. From the viewpoint of improving interlayer adhesiveness, bendability, and heat resistance of the polarizing film, U is preferable¹And U²Are all (meth) acryloyloxy. The (meth) acryloyloxy group may be in a polymerized state or in an unpolymerized state, but is preferably in an unpolymerized state.

As V¹And V²Examples of the alkanediyl group include a methylene group, an ethylene group, a propane-1, 3-diyl group, a butane-1, 4-diyl group, a pentane-1, 5-diyl group, a hexane-1, 6-diyl group, a heptane-1, 7-diyl group, an octane-1, 8-diyl group, a decane-1, 10-diyl group, a tetradecane-1, 14-diyl group, and an eicosane-1, 20-diyl group. V¹And V²Preferably a C2-12 alkanediyl group, and more preferably a C6-12 alkanediyl group.

Examples of the substituent optionally contained in the alkanediyl group include a cyano group and a halogen atom, and the alkanediyl group is preferably an unsubstituted, more preferably an unsubstituted, linear alkanediyl group.

W¹And W²Independently of one another, is preferably a single bond, -O-, -S-, -COO-or OCOO-, more preferably a single bond or O-.

The polymerizable liquid crystal compound (a) is not particularly limited as long as it is a polymerizable liquid crystal compound having at least one (meth) acryloyl group, and known polymerizable liquid crystal compounds, preferably having smectic liquid crystallinity, and a structure which easily exhibits smectic liquid crystallinity, preferably having an asymmetric molecular structure in the molecular structure, more specifically, polymerizable liquid crystal compounds having partial structures of the following (a-a) to (a-i), and polymerizable liquid crystal compounds exhibiting smectic liquid crystallinity can be used. From the viewpoint of easily exhibiting higher order smectic liquid crystallinity, a partial structure having (A-a), (A-b) or (A-c) is more preferable. In the following (A-a) to (A-i), the symbol "A" represents a bond (single bond).

Specific examples of the polymerizable liquid crystal compound (A) include compounds represented by the formulae (A-1) to (A-25). When the polymerizable liquid crystal compound (a) has a cyclohexane-1, 4-diyl group, the cyclohexane-1, 4-diyl group is preferably a trans-isomer.

Among them, preferred is at least one selected from the group consisting of compounds represented by the formula (A-2), the formula (A-3), the formula (A-4), the formula (A-5), the formula (A-6), the formula (A-7), the formula (A-8), the formula (A-13), the formula (A-14), the formula (A-15), the formula (A-16) and the formula (A-17). The polymerizable liquid crystal compound (a) may be used alone in 1 kind, or may be used in combination in 2 or more kinds.

The polymerizable liquid crystal compound (A) can be produced by a known method described in, for example, Recl.Trav.Chim.Pays-Bas,115,321-328(1996), Lub et al, or Japanese patent No. 4719156.

In the present invention, the composition for forming a polarizer may contain other polymerizable liquid crystal compounds than the polymerizable liquid crystal compound (a), and the proportion of the polymerizable liquid crystal compound (a) to the total mass of all the polymerizable liquid crystal compounds contained in the composition for forming a polarizer is preferably 51 mass% or more, more preferably 70 mass% or more, and further preferably 90 mass% or more, from the viewpoint of obtaining a polarizer having a high degree of alignment order.

When the composition for forming a polarizer contains 2 or more polymerizable liquid crystal compounds (a), at least 1 of them may be the polymerizable liquid crystal compound (a1), or all of them may be the polymerizable liquid crystal compound (a 1). By combining a plurality of polymerizable liquid crystal compounds, the liquid crystal properties can be temporarily maintained even at a temperature not higher than the liquid crystal-to-crystal transition temperature in some cases.

The content of the polymerizable liquid crystal compound in the composition for forming a polarizer is preferably 40 to 99.9% by mass, more preferably 60 to 99% by mass, and still more preferably 70 to 99% by mass, based on the solid content of the composition for forming a polarizer. When the content of the polymerizable liquid crystal compound is within the above range, the alignment of the polymerizable liquid crystal compound tends to be high. In the present specification, the solid component refers to the total amount of components remaining after the solvent is removed from the polarizer-forming composition.

In the present invention, the composition for forming a polarizer contains a dichroic pigment. Here, the dichroic dye is a dye having a property that the absorbance of molecules in the major axis direction is different from the absorbance of molecules in the minor axis direction. The dichroic pigment usable in the present invention is not particularly limited, and may be a dye or a pigment as long as it has the above-described properties. In addition, 2 or more kinds of dyes or pigments may be used in combination, or a dye and a pigment may be used in combination. The dichroic dye may have a polymerizable property or a liquid crystal property.

The dichroic dye preferably has an absorption maximum wavelength (. lamda.) in the range of 300 to 700nm_MAX) The pigment of (1). Examples of such dichroic pigments include acridine pigments, oxazine pigments, cyanine pigments, naphthalene pigments, azo pigments, and anthraquinone pigments.

Examples of the azo dye include monoazo dyes, disazo dyes, trisazo dyes, tetraazo dyes, and stilbene azo dyes, and the disazo dyes and the trisazo dyes are preferable, and examples thereof include compounds represented by the formula (I) (hereinafter, also referred to as "compound (I)").

K¹(-N＝N-K²)_p-N＝N-K³ (I)

[ in the formula (I), K¹And K³Each independently represents a phenyl group which may have a substituent, a naphthyl group which may have a substituent, or a monovalent heterocyclic group which may have a substituent. K²Represents an optionally substituted p-phenylene group, an optionally substituted naphthalene-1, 4-diyl group or an optionally substituted divalent heterocyclic group.

p represents an integer of 1 to 4. When p is an integer of 2 or more, a plurality of K²May be the same or different from each other. In the range where absorption is exhibited in the visible light region, the-N ═ N-bond may be replaced by-C ═ C-, -COO-, -NHCO-, -N ═ CH-bond.]

Examples of the monovalent heterocyclic group include groups obtained by removing 1 hydrogen atom from a heterocyclic compound such as quinoline, thiazole, benzothiazole, thienothiazole, imidazole, benzimidazole, oxazole, and benzoxazole. Examples of the divalent heterocyclic group include groups obtained by removing 2 hydrogen atoms from the above-mentioned heterocyclic compound.

As K¹And K³In (1) phenyl, naphthyl and monovalent heterocyclic group, and K²P-phenylene, naphthalene-1, 4-diyl and divalent heterocyclic ring of (1)Examples of the substituent optionally contained in the group include an alkyl group having 1 to 20 carbon atoms, an alkyl group having 1 to 20 carbon atoms and having a polymerizable group, and an alkenyl group having 1 to 4 carbon atoms; alkoxy groups having 1 to 20 carbon atoms such as methoxy, ethoxy, butoxy and the like; an alkyl group having 1 to 20 carbon atoms and having a polymerizable group; a fluorinated alkyl group having 1 to 4 carbon atoms such as a trifluoromethyl group; a cyano group; a nitro group; a halogen atom; a substituted or unsubstituted amino group such as an amino group, a diethylamino group, or a pyrrolidinyl group (the substituted amino group means an amino group having 1 or 2 alkyl groups having 1 to 6 carbon atoms, an amino group having 1 or 2 alkyl groups having 1 to 6 carbon atoms and having a polymerizable group, or an amino group in which 2 substituted alkyl groups are bonded to each other to form an alkanediyl group having 2 to 8 carbon atoms, and the unsubstituted amino group is-NH₂. ) And the like. Here, the polymerizable group includes an acryloyl group, a methacryloyl group, an acryloyloxy group, a methacryloyloxy group, and the like.

Among the compounds (I), preferred are compounds represented by any one of the following formulae (I-1) to (I-6).

[ formulae (I-1) to (I-8),

B¹～B³⁰independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a cyano group, a nitro group, a substituted or unsubstituted amino group (the definitions of the substituted amino group and the unsubstituted amino group are as described above), a chlorine atom or a trifluoromethyl group.

n1 to n4 each independently represents an integer of 0 to 3.

When n1 is 2 or more, a plurality of B²May be the same as or different from each other,

when n2 is 2 or more, a plurality of B⁶May be the same as or different from each other,

when n3 is 2 or more, a plurality of B⁹May be the same as or different from each other,

when n4 is 2 or more, a plurality of B¹⁴May be the same or different from each other.]

As the anthraquinone dye, a compound represented by the formula (I-9) is preferable.

[ in the formula (I-9),

R¹～R⁸independently of one another, represents a hydrogen atom, -R^x、-NH₂、-NHR^x、-NR^x ₂、-SR^xOr a halogen atom.

R^xRepresents an alkyl group having 1 to 4 carbon atoms or an aryl group having 6 to 12 carbon atoms.]

As the above-mentioned oxazinone dye, a compound represented by the formula (I-10) is preferable.

[ in the formula (I-8),

R⁹～R¹⁵independently of one another, represents a hydrogen atom, -R^x、-NH₂、-NHR^x、-NR^x ₂、-SR^xOr a halogen atom.

R^xRepresents an alkyl group having 1 to 4 carbon atoms or an aryl group having 6 to 12 carbon atoms.]

As the acridine pigment, a compound represented by the formula (I-11) is preferable.

[ in the formula (I-11),

R¹⁶～R²³independently of one another, represents a hydrogen atom, -R^x、-NH₂、-NHR^x、-NR^x ₂、-SR^xOr a halogen atom.

R^xRepresents an alkyl group having 1 to 4 carbon atoms or an aryl group having 6 to 12 carbon atoms.]

In the formula (I-9), the formula (I-10) and the formula (I-11), as R^xExamples of the alkyl group having 1 to 6 carbon atoms include methyl, ethyl, propyl, butyl, pentyl and hexyl, and examples of the aryl group having 6 to 12 carbon atoms include phenyl, toluyl, xylyl and naphthyl.

As the cyanine dye, a compound represented by the formula (I-12) and a compound represented by the formula (I-13) are preferable.

[ in the formula (I-12),

D¹and D²Independently of each other, represents a group represented by any one of the formulae (I-12a) to (I-12 d).

n5 represents an integer of 1 to 3. ]

[ in the formula (I-13),

D³and D⁴Independently of each other, represents a group represented by any one of the formulae (I-13a) to (1-13 h).

n6 represents an integer of 1 to 3. ]

Among these dichroic pigments, azo pigments are preferable, and are suitable for producing a polarizing plate having excellent polarizing properties because of their high linearity.

In the present invention, the weight average molecular weight of the dichroic pigment is usually 300 to 2000, preferably 400 to 1000.

The content of the dichroic dye in the composition for forming a polarizer may be appropriately determined depending on the kind of the dichroic dye used, and is preferably 0.1 to 50 parts by mass, more preferably 0.1 to 20 parts by mass, and still more preferably 0.1 to 12 parts by mass, based on 100 parts by mass of the polymerizable liquid crystal compound. When the content of the dichroic pigment is within the above range, the alignment of the polymerizable liquid crystal compound is not easily disturbed, and a polarizer having a high degree of alignment order can be obtained.

In the present invention, the composition for forming a polarizer may contain a polymerization initiator. The polymerization initiator is a compound capable of initiating the polymerization reaction of the polymerizable liquid crystal compound, and is preferably a photopolymerization initiator in that the polymerization reaction can be initiated at a relatively low temperature. Specifically, a photopolymerization initiator capable of generating an active radical or an acid by the action of light is exemplified, and among them, a photopolymerization initiator capable of generating a radical by the action of light is preferable. The polymerization initiator may be used alone or in combination of two or more.

As the photopolymerization initiator, known photopolymerization initiators can be used, and as the photopolymerization initiator generating active radicals, for example, there are a self-cleavage type photopolymerization initiator and a hydrogen abstraction type photopolymerization initiator.

As the self-cleavage type photopolymerization initiator, a self-cleavage type benzoin-based compound, an acetophenone-based compound, a hydroxyacetophenone-based compound, an α -aminoacetophenone-based compound, an oxime ester-based compound, an acylphosphine oxide-based compound, an azo-based compound, or the like can be used. Further, as the hydrogen abstraction type photopolymerization initiator, a hydrogen abstraction type benzophenone compound, a benzoin ether compound, a benzil ketal compound, a dibenzosuberone compound, an anthraquinone compound, a xanthenone compound, a thioxanthone compound, a halogenated acetophenone compound, a dialkoxyacetophenone compound, a halogenated bisimidazole compound, a halogenated triazine compound, a triazine compound, and the like can be used.

As the photopolymerization initiator generating an acid, iodonium salts, sulfonium salts, and the like can be used.

Among them, from the viewpoint of preventing the dissolution of the dye, a reaction at a low temperature is preferable, and from the viewpoint of reaction efficiency at a low temperature, a self-cleavage type photopolymerization initiator is preferable, and particularly, an acetophenone-based compound, a hydroxyacetophenone-based compound, an α -aminoacetophenone-based compound, and an oxime ester-based compound are preferable.

Examples of the photopolymerization initiator include the following.

Benzoin-based compounds such as benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, and benzoin isobutyl ether;

hydroxyacetophenone-based compounds such as oligomers of 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1, 2-diphenyl-2, 2-dimethoxyethane-1-one, 2-hydroxy-2-methyl-1- [4- (2-hydroxyethoxy) phenyl ] propan-1-one, 1-hydroxycyclohexyl phenyl ketone and 2-hydroxy-2-methyl-1- [4- (1-methylvinyl) phenyl ] propan-1-one;

α -aminoacetophenone-based compounds such as 2-methyl-2-morpholino-1- (4-methylthiophenyl) propan-1-one and 2-dimethylamino-2-benzyl-1- (4-morpholinophenyl) butan-1-one;

oxime ester compounds such as 1, 2-octanedione-1- [4- (phenylthio) -2- (O-benzoyloxime) ], 1- [ 9-ethyl-6- (2-methylbenzoyl) -9H-carbazol-3-yl ] -ethanone-1- (O-acetyloxime);

acylphosphine oxide-based compounds such as 2,4, 6-trimethylbenzoyldiphenylphosphine oxide and bis (2,4, 6-trimethylbenzoyl) phenylphosphine oxide;

benzophenone compounds such as benzophenone, methyl o-benzoylbenzoate, 4-phenylbenzophenone, 4-benzoyl-4 ' -methyldiphenyl sulfide, 3 ', 4,4 ' -tetrakis (t-butylperoxycarbonyl) benzophenone, and 2,4, 6-trimethylbenzophenone;

dialkoxyacetophenone-based compounds such as diethoxyacetophenone;

2, 4-bis (trichloromethyl) -6- (4-methoxyphenyl) -1,3, 5-triazine, 2, 4-bis (trichloromethyl) -6- (4-methoxynaphthyl) -1,3, 5-triazine, 2, 4-bis (trichloromethyl) -6- (4-methoxystyryl) -1,3, 5-triazine, 2, 4-bis (trichloromethyl) -6- [2- (5-methylfuran-2-yl) vinyl ] -1,3, 5-triazine, 2, 4-bis (trichloromethyl) -6- [2- (furan-2-yl) vinyl ] -1,3, 5-triazine Triazine compounds such as (E) -2-methylphenyl) vinyl ] -1,3, 5-triazine and (E) -2, 4-bis (trichloromethyl) -6- [2- (3, 4-dimethoxyphenyl) vinyl ] -1,3, 5-triazine.

The photopolymerization initiator may be appropriately selected from the above photopolymerization initiators, for example, in accordance with the relationship with the polymerizable liquid crystal compound contained in the polarizer-forming composition.

Further, a commercially available photopolymerization initiator can be used. Examples of commercially available polymerization initiators include Irgacure (イルガキュア) (registered trademark) 907, 184, 651, 819, 250, 369, 379, 127, 754, OXE01, OXE02, and OXE03 (manufactured by BASF corporation); omnirad BCIM, Escapure 1001M, Escapure KIP160 (manufactured by IDM Resins B.V.); SEIKUOL (registered trademark) BZ, Z and BEE (manufactured by seiko chemical corporation); kayacure (カヤキュアー) (registered trademark) BP100 and UVI-6992 (manufactured by DOW Chemical Company; ADEKA OPTOMER SP-152, N-1717, N-1919, SP-170, ADEKA ARKLS NCI-831, ADEKA ARKLS NCI-930 (manufactured by ADEKA Co., Ltd.); TAZ-A and TAZ-PP (manufactured by Siber Hegner Co., Ltd., Japan)), and TAZ-104 (manufactured by Sanwa Chemical Co., Ltd.); and the like.

The content of the polymerization initiator in the composition for forming a polarizer is preferably 1 to 10 parts by mass, more preferably 1 to 8 parts by mass, still more preferably 2 to 8 parts by mass, and particularly preferably 4 to 8 parts by mass, based on 100 parts by mass of the polymerizable liquid crystal compound. When the content of the polymerization initiator is within the above range, the polymerization reaction of the polymerizable liquid crystal compound can be carried out without greatly disturbing the orientation of the polymerizable liquid crystal compound.

The polymerization rate of the polymerizable liquid crystal compound in the polarizer of the present invention is preferably 60% or more, more preferably 65% or more, and even more preferably 70% or more, from the viewpoint of line contamination and handling during production.

The composition for forming a polarizer may further contain a photosensitizer. By using the photosensitizer, the polymerization reaction of the polymerizable liquid crystal compound can be further promoted. Examples of the photosensitizing agent include xanthone compounds such as xanthone and thioxanthone (e.g., 2, 4-diethylthioxanthone and 2-isopropylthioxanthone); anthracene compounds such as anthracene and alkoxy-containing anthracene (e.g., dibutoxyanthracene); phenothiazine, rubrene, and the like. The photosensitizers may be used alone or in combination of two or more.

When the composition for forming a polarizer contains a photosensitizer, the content thereof may be determined as appropriate depending on the kind and amount of the polymerization initiator and the polymerizable liquid crystal compound, and is preferably 0.1 to 30 parts by mass, more preferably 0.5 to 10 parts by mass, and still more preferably 0.5 to 8 parts by mass, based on 100 parts by mass of the polymerizable liquid crystal compound.

The composition for forming a polarizer may further include a leveling agent. The leveling agent has a function of adjusting the fluidity of the composition for forming a polarizing plate and flattening a coating film obtained by applying the composition for forming a polarizing plate, and specific examples thereof include surfactants. The leveling agent is preferably at least 1 selected from the group consisting of a leveling agent containing a polyacrylate compound as a main component and a leveling agent containing a fluorine atom-containing compound as a main component. The leveling agent may be used alone or in combination of two or more.

Examples of the leveling agent containing a polyacrylate compound as a main component include "BYK-350", "BYK-352", "BYK-353", "BYK-354", "BYK-355", "BYK-358N", "BYK-361N", "BYK-380", "BYK-381", and "BYK-392" (BYK Chemie Co.).

Examples of the leveling agent containing a fluorine atom-containing compound as a main component include "MEGAFACE (registered trademark) R-08", MEGAFACE "R-30", MEGAFACE "R-90", MEGAFACE "F-410", MEGAFACE "F-411", MEGAFACE "F-443", MEGAFACE "F-445", MEGAFACE "F-470", MEGAFACE "F-471", MEGAFACE "F-477", MEGAFACE "F-479", MEGAFACE "F-482", and MEGAFACE "F-483" (DIC corporation); "Surflon (registered trademark) S-381", Surflon "S-382", Surflon "S-383", Surflon "S-393", Surflon "SC-101", Surflon "SC-105", "KH-40" and "SA-100" (AGC Seimi Chemical Co., Ltd.); "E1830", "E5844" (Daikin Fine Chemical Kenkyusho, K.K.); "EFTOP EF 301", "EFTOP EF 303", "EFTOP EF 351" and "EFTOP EF 352" (Mitsubishi Materials Electronic Chemicals Co., Ltd.).

When the composition for forming a polarizer contains a leveling agent, the content thereof is preferably 0.05 to 5 parts by mass, and more preferably 0.05 to 3 parts by mass, based on 100 parts by mass of the polymerizable liquid crystal compound. If the content of the leveling agent is within the above range, the following tendency is present: the polymerizable liquid crystal compound is easily horizontally aligned, and unevenness is less likely to occur, so that a smoother polarizer can be obtained.

The composition for forming a polarizer may contain other additives in addition to the photosensitizing agent and the leveling agent.

Examples of the other additives include colorants such as antioxidants, mold release agents, stabilizers, and bluing agents, flame retardants, and lubricants. When the composition for forming a polarizer contains other additives, the content of the other additives is preferably more than 0% and 20% by mass or less, and more preferably more than 0% and 10% by mass or less, with respect to the solid components of the composition for forming a polarizer.

The composition for forming a polarizer can be produced by a conventionally known method for producing a composition for forming a polarizer, and can be usually produced by mixing and stirring a polymerizable liquid crystal compound, a dichroic dye, and, if necessary, a polymerization initiator, the above-mentioned additives, and the like. In addition, since the viscosity of the compound exhibiting smectic liquid crystallinity is generally high, the viscosity can be adjusted by adding a solvent to the composition for forming a polarizer, from the viewpoint of improving the coatability of the composition for forming a polarizer and facilitating the formation of a polarizer.

The solvent used in the composition for forming a polarizer may be appropriately selected depending on the solubility of the polymerizable liquid crystal compound and the dichroic dye used. Specific examples thereof include water, alcohol solvents such as methanol, ethanol, ethylene glycol, isopropanol, propylene glycol, methyl cellosolve, butyl cellosolve, and propylene glycol monomethyl ether, ester solvents such as ethyl acetate, butyl acetate, ethylene glycol methyl ether acetate, γ -butyrolactone, propylene glycol methyl ether acetate, and ethyl lactate, ketone solvents such as acetone, methyl ethyl ketone, cyclopentanone, cyclohexanone, methyl amyl ketone, and methyl isobutyl ketone, aliphatic hydrocarbon solvents such as pentane, hexane, and heptane, aromatic hydrocarbon solvents such as toluene and xylene, nitrile solvents such as acetonitrile, ether solvents such as tetrahydrofuran and dimethoxyethane, and chlorinated hydrocarbon solvents such as chloroform and chlorobenzene. These solvents may be used alone or in combination of two or more. The content of the solvent is preferably 100 to 1900 parts by mass, more preferably 150 to 900 parts by mass, and still more preferably 180 to 600 parts by mass, per 100 parts by mass of the solid components of the polarizer forming composition.

In the polarizing film of the present invention, the polarizer is preferably a polarizer having a high degree of orientation order. In a polarizer having a high degree of orientation order, bragg peaks derived from a higher-order structure such as a hexagonal phase (hexagonal phase) or a crystal phase are shown in X-ray diffraction measurement. The bragg peak is a peak derived from a plane periodic structure of molecular orientation. Therefore, the polarizer constituting the polarizing film of the present invention preferably exhibits bragg peaks in X-ray diffraction measurement. That is, in the polarizer constituting the polarizing film of the present invention, the polymerizable liquid crystal compound or a polymer thereof is preferably oriented so that the polarizer shows bragg peaks in X-ray diffraction measurement, and more preferably "horizontal orientation" in which molecules of the polymerizable liquid crystal compound are oriented in a direction of absorbing light. In the present invention, the plane period interval of the preferred molecular orientation isThe polarizer of (1). The high degree of alignment order such as the bragg peak can be realized by controlling the type of the polymerizable liquid crystal compound used, the type and amount of the dichroic dye, the type and amount of the polymerization initiator, and the like.

In one embodiment of the present invention, the polarizer may be obtained by a method including the steps of: forming a coating film of the composition for forming a polarizer on the alignment film; removing the solvent from the coating film; heating to a temperature higher than the temperature at which the polymerizable liquid crystal compound phase changes into a liquid phase, and then cooling to change the polymerizable liquid crystal compound phase into a smectic phase; and polymerizing the polymerizable liquid crystal compound while maintaining the smectic phase.

Examples of the method for applying the composition for forming a polarizer to an alignment film include known methods such as a spin coating method, an extrusion method, a gravure coating method, a die coating method, a bar coating method, a coating method such as a coater method, and a printing method such as a flexo method.

Next, the solvent is removed by drying or the like under the condition that the polymerizable liquid crystal compound contained in the coating film obtained from the composition for forming a polarizer is not polymerized, whereby a dried coating film can be formed. Examples of the drying method include natural drying, air drying, heat drying, and reduced-pressure drying.

Further, in order to change the polymerizable liquid crystal compound phase to a liquid phase, the temperature is raised to a temperature equal to or higher than the temperature at which the polymerizable liquid crystal compound phase changes to a liquid phase, and then the temperature is lowered to change the polymerizable liquid crystal compound phase to a smectic phase (smectic liquid crystal state). The phase transition may be performed after the removal of the solvent in the coating film, or may be performed simultaneously with the removal of the solvent.

The polymerizable liquid crystal compound is polymerized while being maintained in a smectic liquid crystal state of the polymerizable liquid crystal compound, thereby forming a polarizer as a cured layer of the composition for forming a polarizer. The polymerization method is preferably a photopolymerization method. In photopolymerization, the light to be irradiated to the dried coating film can be appropriately selected depending on the kind of the polymerizable liquid crystal compound contained in the dried coating film (particularly, the kind of the polymerizable group contained in the polymerizable liquid crystal compound), the kind of the polymerization initiator, the amount thereof, and the like. Specific examples thereof include 1 or more active energy rays selected from the group consisting of visible light, ultraviolet light, infrared light, X-rays, α -rays, β -rays, and γ -rays, and an active electron beam. Among them, ultraviolet light is preferable from the viewpoint that the progress of the polymerization reaction is easily controlled and a device widely used in the art as a photopolymerization device can be used, and it is preferable that the kinds of the polymerizable liquid crystal compound and the polymerization initiator contained in the composition for forming a polarizer are selected in advance so that photopolymerization can be performed by ultraviolet light. In addition, during polymerization, the polymerization temperature may be controlled by irradiating with light while cooling the dried coating film by an appropriate cooling means. When photopolymerization is performed, a patterned polarizer may be obtained by masking, development, or the like.

Examples of the light source of the active energy ray include a low-pressure mercury lamp, a medium-pressure mercury lamp, a high-pressure mercury lamp, an ultrahigh-pressure mercury lamp, a xenon lamp, a halogen lamp, a carbon arc lamp, a tungsten lamp, a gallium lamp, an excimer laser, an LED light source emitting light in a wavelength range of 380 to 440nm, a chemical lamp, a black light lamp, a microwave-excited mercury lamp, a metal halide lamp, and the like.

The ultraviolet irradiation intensity is usually 10-3000 mW/cm². The ultraviolet irradiation intensity is preferably an intensity in a wavelength region effective for activation of the polymerization initiator. The time for irradiating light is usually 0.1 second to 10 minutes, preferably 1 second to 5 minutes, more preferably 5 seconds to 3 minutes, and further preferably 10 seconds to 1 minute. When the ultraviolet irradiation intensity is applied for 1 or more times, the cumulative light quantity is 10 to 3000mJ/cm²Preferably 50 to 2000mJ/cm²More preferably 100 to 1000mJ/cm²。

By photopolymerization, the polymerizable liquid crystal compound is polymerized while being kept in a liquid crystal state of a smectic phase, preferably a high order smectic phase, to form a polarizer. The polarizer obtained by polymerizing the polymerizable liquid crystal compound in a state of maintaining a liquid crystal state of a smectic phase also has an advantage that the polarizing performance is higher than that of a conventional bulk-guest polarizing film, that is, a polarizer formed in a liquid crystal state of a nematic phase, with the action of the dichroic dye. Further, the polarizing plate has an advantage of being superior in strength to a polarizing plate coated with only a dichroic dye or a lyotropic liquid crystal.

The thickness of the polarizer may be appropriately selected according to the display device to be used, and is preferably 0.1 to 5 μm, more preferably 0.3 to 4 μm, and still more preferably 0.5 to 3 μm. When the film thickness of the polarizer is not less than the above-described lower limit, it is easy to prevent the failure to obtain necessary light absorption, and when the film thickness is not more than the above-described upper limit, it is easy to suppress the occurrence of alignment defects due to a decrease in alignment regulating force by the alignment film. The polarizing film, the polarizer, the alignment film, the 1 st resin layer and the 2 nd resin layer, and the polarizing plate described later can be measured by a laser microscope or a film thickness meter.

< alignment film >

The oriented film included in the polarizing film of the present invention is formed on the surface of the polarizer opposite to the 1 st resin layer. The alignment film is a film having an alignment regulating force for aligning the liquid crystal of the polymerizable liquid crystal compound in a desired direction. The alignment film preferably has solvent resistance that does not dissolve due to application of the polarizing film-forming composition or the like, and heat resistance in heat treatment for removing the solvent and aligning the polymerizable liquid crystal compound. In the present invention, the alignment film is a cured product of the alignment film-forming composition containing a (meth) acrylic compound, and has excellent adhesion to the interface with the polarizer and the interface with the 2 nd resin layer. The alignment film in the present invention is preferably a photo-alignment film formed by curing the alignment film-forming composition with polarized light (preferably polarized UV light) from the viewpoint of improving adhesiveness and bendability.

The (meth) acrylic compound in the alignment film forming composition represents a compound having at least one (meth) acryloyl group, and the (meth) acrylic compound may be a monomer, an oligomer, or a polymer. In the case of an oligomer or polymer, the double bond of the (meth) acryloyl group may be polymerized. The (meth) acrylic compound contained in the composition for forming a photoalignment film preferably has a photoreactive group in addition to a (meth) acryloyl group.

The photoreactive group refers to a group that generates liquid crystal alignment ability by light irradiation. Specifically, there may be mentioned groups which participate in photoreaction originating from liquid crystal aligning ability, such as orientation induction or isomerization reaction, dimerization reaction, photocrosslinking reaction, or photolysis reaction of molecules by light irradiation. Among them, a group participating in dimerization reaction or photocrosslinking reaction is preferable from the viewpoint of excellent orientation. As the photoreactive group, a group having an unsaturated bond, particularly a double bond is preferable, and particularly, at least 1 group selected from the group consisting of a carbon-carbon double bond (C ═ C bond), a carbon-nitrogen double bond (C ═ N bond), a nitrogen-nitrogen double bond (N ═ N bond), and a carbon-oxygen double bond (C ═ O bond) is preferable.

Examples of the photoreactive group having a C ═ C bond include a vinyl group, a polyene group, a stilbene group, a stilbenazolyl group, a stilbazolium group, a chalcone group, and a cinnamoyl group. Examples of the photoreactive group having a C ═ N bond include groups having a structure of an aromatic schiff base, an aromatic hydrazone, or the like. Examples of the photoreactive group having an N ═ N bond include an azophenyl group, an azonaphthyl group, an aromatic heterocyclic azo group, a bisazo group, and a methyl groupA group having an azoxybenzene structure, and the like. Examples of the photoreactive group having a C ═ O bond include a benzophenone group, a coumarin group, an anthraquinone group, and a maleimide group. These groups may have substituents such as alkyl, alkoxy, aryl, allyloxy, cyano, alkoxycarbonyl, hydroxyl, sulfonic acid, and haloalkyl.

Among them, a photoreactive group participating in a photodimerization reaction is preferable, and cinnamoyl group and chalcone group are preferable in terms of a small amount of polarized light irradiation required for photo-alignment, easy obtainment of a photo-alignment film having excellent thermal stability and temporal stability. As the (meth) acrylic oligomer or polymer contained in the composition for forming a photoalignment film, a substance in which the terminal part of the side chain of the oligomer or polymer has a cinnamoyl group having a cinnamic acid structure is particularly preferable.

In one embodiment of the present invention, the photo-alignment film may be obtained by: the composition for forming a photo-alignment film, which contains a (meth) acrylic compound and a solvent, is applied to the 2 nd resin layer and irradiated with polarized light (preferably polarized UV light). The solvent contained in the composition for forming a photoalignment film includes the same solvents as those exemplified above as the solvents that can be used in the formation of a polarizer, and can be appropriately selected depending on the solubility of the (meth) acrylic compound.

The content of the (meth) acrylic compound in the composition for forming a photo-alignment film may be appropriately adjusted depending on the kind of the (meth) acrylic compound and the thickness of the target photo-alignment film, and is preferably at least 0.2% by mass, and more preferably in the range of 0.3 to 10% by mass, based on the mass of the composition for forming a photo-alignment film. The composition for forming a photo-alignment film may contain a polymer material such as polyvinyl alcohol or polyimide, and a photosensitizer within a range that does not significantly impair the characteristics of the photo-alignment film.

Examples of the method of applying the composition for forming a photoalignment film to the 2 nd resin layer and the method of removing the solvent from the applied composition for forming a photoalignment film include the methods exemplified above as a method of applying the composition for forming a polarizer to an alignment film and a method of removing the solvent.

The irradiation with polarized light may be performed by directly irradiating polarized UV light to a product obtained by removing the solvent from the composition for forming a photoalignment film applied to the 2 nd resin layer, or may be performed by irradiating polarized light from the 2 nd resin layer side and transmitting the polarized light. In addition, the polarized light is particularly preferably substantially parallel light. The wavelength of the polarized light to be irradiated may be a wavelength in a wavelength region where the photoreactive group and/or the (meth) acryloyl group of the (meth) acrylic compound can absorb light energy. Specifically, UV (ultraviolet) light having a wavelength of 250 to 400nm is particularly preferable. Examples of the light source used for the polarized light irradiation include a xenon lamp, a high-pressure mercury lamp, an ultrahigh-pressure mercury lamp, a metal halide lamp, and ultraviolet laser such as KrF and ArF, and the high-pressure mercury lamp, the ultrahigh-pressure mercury lamp, and the metal halide lamp are more preferable. Among these, a high-pressure mercury lamp, an ultrahigh-pressure mercury lamp, and a metal halide lamp are preferable because the emission intensity of ultraviolet rays having a wavelength of 313nm is large. Polarized UV light can be irradiated by irradiating light from the light source through an appropriate polarizer. As the polarizer, a polarizing filter, a polarizing prism of glan-thompson, glan-taylor, or the like, a wire grid type polarizer may be used.

In the rubbing or the polarized light irradiation, a plurality of regions (patterns) having different liquid crystal alignment directions may be formed by masking.

The thickness of the alignment film is preferably 10 to 5000nm, more preferably 10 to 1000nm, and still more preferably 30 to 300 nm. When the thickness of the alignment film is within the above range, good adhesion to the interface with the polarizer or the interface with the 2 nd resin layer can be exhibited, and an alignment regulating force is exerted, so that the polarizer can be formed in a high alignment order.

< the 1 st resin layer and the 2 nd resin layer >

The 1 st resin layer contained in the polarizing film of the present invention is a cured product of a1 st curable composition containing a (meth) acrylic compound, and is formed on the surface of the polarizer opposite to the alignment film side. In the present invention, since the 1 st resin layer and the polarizer are both formed of a compound having a (meth) acryloyl group, the compatibility between layers is high, and the (meth) acrylic compound contained in the 1 st curable composition and the (meth) acrylic compound contained in the alignment film can form a crosslinked structure. Therefore, the polarizing film of the present invention can exhibit excellent adhesion at the interface of the 1 st resin layer.

The 2 nd resin layer contained in the polarizing film of the present invention is a cured product of a 2 nd curable composition containing a (meth) acrylic compound, and is formed on the surface of the alignment film opposite to the polarizer side. In the present invention, since both the 2 nd resin layer and the alignment film are formed of a compound having a (meth) acryloyl group, the compatibility between layers is high, and the (meth) acrylic compound contained in the 2 nd curable composition and the polymerizable liquid crystal compound having a (meth) acryloyl group contained in the polarizer can form a crosslinked structure. Therefore, the polarizing film of the present invention can exhibit excellent adhesion at the interface of the 2 nd resin layer.

The (meth) acrylic compound contained in the 1 st curable composition and the 2 nd curable composition is a compound having at least one (meth) acryloyl group, and may be a monomer, an oligomer, or a polymer.

In the present invention, at least one (preferably both) of the 1 st curable composition and the 2 nd curable composition contains (meth) acryloyl groups in an amount of 40 × 10 per unit molecular weight^-4The following urethane (meth) acrylate compounds are used as the (meth) acrylic compounds. When such a urethane (meth) acrylate compound is contained, excellent flexibility can be exhibited. It is to be noted that the number of (meth) acryloyl groups per unit molecular weight may be represented by the formula: the number of (meth) acryloyl groups/weight average molecular weight (Mw) of the urethane (meth) acrylate compound was calculated. In the present specification, bendability means the following characteristics: when the polarizing film is bent, the occurrence of cracks and the like can be suppressed.

In the urethane (meth) acrylate compound, the number of (meth) acryloyl groups per unit molecular weight is preferably 30X 10^-4Hereinafter, more preferably 20 × 10^-4The following. When the number of (meth) acryloyl groups per unit molecular weight is in the above range, the bendability of the polarizing film is more easily improved. The lower limit of the number of (meth) acryloyl groups per unit molecular weight is preferably 1X 10^-5Above, more preferably 1 × 10^-4The above.

The urethane (meth) acrylate compound is generally a reaction product of an isocyanate compound, a polyol compound, and a (meth) acrylate compound, and is preferably a polyfunctional urethane (meth) acrylate compound having 2 or more (meth) acryloyloxy groups in the molecule. The polyfunctional urethane (meth) acrylate compound can form a cross-linked structure favorable for bending, and thus the bendability of the polarizing film is easily improved.

The polyfunctional urethane (meth) acrylate compound preferably has 2 to 5 functional groups from the viewpoint of flexibility.

The weight average molecular weight (Mw) of the urethane (meth) acrylate compound is preferably 300 or more, more preferably 400 or more, further preferably 1000 or more, particularly preferably 2000 or more, preferably 10,000 or less, more preferably 7,000 or less, and further preferably 5,000 or less in terms of polystyrene. When the Mw of the urethane (meth) acrylate compound is within the above range, the adhesiveness and the flexibility are easily improved. The weight average molecular weight (Mw) can be measured by, for example, Gel Permeation Chromatography (GPC).

The 1 st curable composition and/or the 2 nd curable composition may contain one or two or more urethane (meth) acrylate compounds. When two or more urethane (meth) acrylate compounds are contained, the number of (meth) acryloyl groups per unit molecular weight, the weight average molecular weight, and the like may differ between the urethane (meth) acrylate compounds.

The number of (meth) acryloyl groups per unit molecular weight in the 1 st or 2 nd curable composition was 40X 10^-4The content of the following urethane (meth) acrylate compound is preferably 10 parts by mass or more, more preferably 30 parts by mass or more, and preferably 100 parts by mass or less, with respect to 100 parts by mass of the solid components of the curable composition. When the content of the urethane (meth) acrylate compound is in the above range, the adhesiveness, the flexibility, and the heat resistance of the polarizing film are easily improved.

In one embodiment of the present invention, at least one of the 1 st curable composition and the 2 nd curable composition may further contain a polyfunctional (meth) acrylate compound as the (meth) acrylic compound. When such a polyfunctional (meth) acrylate compound is contained, the bendability of the polarizing film is easily improved. In addition, the heat resistance can be improved by combining with the urethane (meth) acrylate compound.

In the present invention, the polyfunctional (meth) acrylate compound is usually a (meth) acrylate compound having no urethane bond and is a compound different from the urethane (meth) acrylate compound.

The polyfunctional (meth) acrylate compound is a compound having 2 or more (meth) acryloyloxy groups in the molecule, and examples thereof include a 2-functional (meth) acrylate monomer having 2 (meth) acryloyloxy groups in the molecule, and a 3-functional (meth) acrylate monomer having 3 or more (meth) acryloyloxy groups in the molecule. In the present specification, the term "(meth) acrylate" means "acrylate" or "methacrylate", and similarly, the term "(meth) acryloyl" means "acryloyl" or "methacryloyl".

The 1 st curable composition or the 2 nd curable composition may contain two or more kinds of polyfunctional (meth) acrylate compounds as the polyfunctional (meth) acrylate compounds. In the case where two or more kinds of polyfunctional (meth) acrylate compounds are contained, the number of (meth) acryloyloxy groups may be the same or different among the polyfunctional (meth) acrylate compounds.

The molecular weight of the polyfunctional (meth) acrylate compound is preferably 100 to 2000, more preferably 200 to 1500.

Examples of the 2-functional (meth) acrylate monomer include alkylene glycol di (meth) acrylates such as ethylene glycol di (meth) acrylate, 1, 3-butanediol di (meth) acrylate, 1, 4-butanediol di (meth) acrylate, 1, 6-hexanediol di (meth) acrylate, 1, 9-nonanediol di (meth) acrylate, and neopentyl glycol di (meth) acrylate; polyoxyalkylene glycol di (meth) acrylates such as diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, tripropylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, and polytetramethylene glycol di (meth) acrylate; di (meth) acrylates of halogen-substituted alkylene glycols such as tetrafluoroethylene di (meth) acrylate; di (meth) acrylates of aliphatic polyhydric alcohols such as trimethylolpropane di (meth) acrylate, ditrimethylolpropane di (meth) acrylate, pentaerythritol di (meth) acrylate and the like; hydrogenated dicyclopentadiene or tricyclodecane dialkanol di (meth) acrylates such as hydrogenated dicyclopentadiene di (meth) acrylate and tricyclodecane dimethanol di (meth) acrylate; 1, 3-dioxane-2, 5-diylbis (meth) acrylate [ alternative name: dioxane diol or a di (meth) acrylate of dioxane diol such as dioxane diol di (meth) acrylate; di (meth) acrylates of alkylene oxide adducts of bisphenol a or bisphenol F such as bisphenol a ethylene oxide adduct diacrylate and bisphenol F ethylene oxide adduct diacrylate; epoxy di (meth) acrylates of bisphenol a or bisphenol F such as acrylic acid adducts of bisphenol a diglycidyl ether and acrylic acid adducts of bisphenol F diglycidyl ether; silicone di (meth) acrylate; di (meth) acrylate of neopentyl glycol hydroxypivalate; 2, 2-bis [4- (meth) acryloyloxyethoxyethoxyphenyl ] propane; 2, 2-bis [4- (meth) acryloyloxyethoxyethoxyethoxycyclohexyl ] propane; di (meth) acrylate of 2- (2-hydroxy-1, 1-dimethylethyl) -5-ethyl-5-hydroxymethyl-1, 3-dioxane); tris (hydroxyethyl) isocyanurate di (meth) acrylate, and the like.

The 3-functional (meth) acrylate monomer is a monomer having 3 (meth) acryloyloxy groups in the molecule, and examples thereof include glycerol tri (meth) acrylate, trimethylolpropane tri (meth) acrylate, ditrimethylolpropane tri (meth) acrylate, pentaerythritol tri (meth) acrylate, a reaction product of pentaerythritol tri (meth) acrylate and an acid anhydride, caprolactone-modified trimethylolpropane tri (meth) acrylate, caprolactone-modified pentaerythritol tri (meth) acrylate, ethylene oxide-modified trimethylolpropane tri (meth) acrylate, ethylene oxide-modified pentaerythritol tri (meth) acrylate, propylene oxide-modified trimethylolpropane tri (meth) acrylate, propylene oxide-modified pentaerythritol tri (meth) acrylate, isocyanurate tri (meth) acrylate, and the like, A reaction product of caprolactone-modified pentaerythritol tri (meth) acrylate and acid anhydride, a reaction product of ethylene oxide-modified pentaerythritol tri (meth) acrylate and acid anhydride, a reaction product of propylene oxide-modified pentaerythritol tri (meth) acrylate and acid anhydride, and the like.

The 4-functional (meth) acrylate monomer is a monomer having 4 (meth) acryloyloxy groups in the molecule, and examples thereof include ditrimethylolpropane tetra (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol tetra (meth) acrylate, tripentaerythritol tetra (meth) acrylate, caprolactone-modified pentaerythritol tetra (meth) acrylate, caprolactone-modified tripentaerythritol tetra (meth) acrylate, ethylene oxide-modified pentaerythritol tetra (meth) acrylate, ethylene oxide-modified tripentaerythritol tetra (meth) acrylate, propylene oxide-modified pentaerythritol tetra (meth) acrylate, propylene oxide-modified tripentaerythritol tetra (meth) acrylate, and the like.

Examples of the 5-functional (meth) acrylate monomer include dipentaerythritol penta (meth) acrylate, tripentaerythritol penta (meth) acrylate, a reaction product of dipentaerythritol penta (meth) acrylate and an acid anhydride, caprolactone-modified dipentaerythritol penta (meth) acrylate, caprolactone-modified tripentaerythritol penta (meth) acrylate, ethylene oxide-modified dipentaerythritol penta (meth) acrylate, ethylene oxide-modified tripentaerythritol penta (meth) acrylate, propylene oxide-modified dipentaerythritol penta (meth) acrylate, propylene oxide-modified tripentaerythritol penta (meth) acrylate, a reaction product of caprolactone-modified dipentaerythritol penta (meth) acrylate and acid anhydride, a reaction product of ethylene oxide-modified dipentaerythritol penta (meth) acrylate and acid anhydride, a reaction product of propylene oxide-modified dipentaerythritol penta (meth) acrylate and acid anhydride, and the like.

Examples of the 6-functional (meth) acrylate monomer include dipentaerythritol hexa (meth) acrylate, tripentaerythritol hexa (meth) acrylate, caprolactone-modified dipentaerythritol hexa (meth) acrylate, caprolactone-modified tripentaerythritol hexa (meth) acrylate, ethylene oxide-modified dipentaerythritol hexa (meth) acrylate, ethylene oxide-modified tripentaerythritol hexa (meth) acrylate, propylene oxide-modified dipentaerythritol hexa (meth) acrylate, and propylene oxide-modified tripentaerythritol hexa (meth) acrylate.

Examples of the 7-functional (meth) acrylate monomer include tripentaerythritol hepta (meth) acrylate, a reaction product of tripentaerythritol hepta (meth) acrylate and an acid anhydride, caprolactone-modified tripentaerythritol hepta (meth) acrylate, a reaction product of caprolactone-modified tripentaerythritol hepta (meth) acrylate and an acid anhydride, ethylene oxide-modified tripentaerythritol hepta (meth) acrylate, a reaction product of ethylene oxide-modified tripentaerythritol hepta (meth) acrylate and an acid anhydride, propylene oxide-modified tripentaerythritol hepta (meth) acrylate, and a reaction product of propylene oxide-modified tripentaerythritol hepta (meth) acrylate and an acid anhydride.

The 8-functional (meth) acrylate monomer is a monomer having 8 (meth) acryloyloxy groups in the molecule, and examples thereof include tripentaerythritol octa (meth) acrylate, caprolactone-modified tripentaerythritol octa (meth) acrylate, ethylene oxide-modified tripentaerythritol octa (meth) acrylate, propylene oxide-modified tripentaerythritol octa (meth) acrylate, and the like. These polyfunctional (meth) acrylate compounds may be used alone or in combination of two or more.

In one embodiment of the present invention, the number of (meth) acryloyl groups in the polyfunctional (meth) acrylate compound is preferably 6 or less. When the number of (meth) acryloyl groups is 6 or less, the crosslinking density decreases, and a crosslinked structure favorable for bending can be formed, so that the bendability of the polarizing film can be more easily improved. In addition, the heat resistance can be further improved.

Examples of the polyfunctional (meth) acrylate compound having 6 or less (meth) acryloyl groups include the 2-functional (meth) acrylate monomer having 2 (meth) acryloyloxy groups in the molecule, and the 3 to 6-functional (meth) acrylate monomer having 3 to 6 (meth) acryloyloxy groups in the molecule.

In one embodiment of the present invention, the polyfunctional (meth) acrylate compound has a branched structure, and the number of atoms of a chain (sometimes referred to as a "linking chain") linking a branch point closest to a (meth) acryloyl group in the branched structure to the (meth) acryloyl group is preferably 2 or more, more preferably 4 or more, and still more preferably 7 or more, from the viewpoint of controlling the crosslinking density to improve adhesiveness and bendability. When the number of atoms is not more than the upper limit, the crosslinking density of the 1 st resin layer or the 2 nd resin layer is decreased, and the bendability of the polarizing film is easily improved. Here, when there are a plurality of such linking chains, at least one linking chain may satisfy the above-mentioned range of the number of atoms, and from the viewpoint of improving bendability, it is preferable that all the linking chains satisfy the above-mentioned range of the number of atoms.

Among the above multifunctional (meth) acrylate compounds, dipentaerythritol hexa (meth) acrylate, tripentaerythritol hexa (meth) acrylate, ethylene oxide-modified tripentaerythritol hexa (meth) acrylate, propylene oxide-modified dipentaerythritol hexa (meth) acrylate, and propylene oxide-modified tripentaerythritol hexa (meth) acrylate are preferable from the viewpoint of adhesiveness and bendability of the polarizing film, and ethylene oxide-modified dipentaerythritol hexa (meth) acrylate is more preferable.

When the 1 st curable composition or the 2 nd curable composition contains a polyfunctional (meth) acrylate compound, the content of the polyfunctional (meth) acrylate compound is preferably 50 parts by mass or more, more preferably 60 parts by mass or more, further preferably 70 parts by mass or more, preferably 95 parts by mass or less, and further preferably 90 parts by mass or less, per 100 parts by mass of the solid components of the curable composition. When the content of the polyfunctional (meth) acrylate compound is in the above range, the interlayer adhesiveness, the flexibility and the heat resistance of the polarizing film are easily improved. In the present specification, the term "solid component of the curable composition" means the total amount of components remaining after removing a solvent from the curable composition when the solvent is contained in the curable composition.

When the 1 st curable composition or the 2 nd curable composition contains a polyfunctional (meth) acrylate compound and a urethane (meth) acrylate compound, it is preferable to add a polyfunctional (meth) acrylate compound to the urethane (meth) acrylate compound in an amount of preferably 95: 5-50: 50. more preferably 90: 10-70: a ratio of 30 (polyfunctional (meth) acrylate compound: urethane (meth) acrylate compound, mass ratio) includes the polyfunctional (meth) acrylate compound and the urethane (meth) acrylate compound. When the polyfunctional (meth) acrylate compound and the urethane (meth) acrylate compound are contained in the above blending ratio, the adhesiveness, the flexibility, and the heat resistance of the polarizing film can be easily improved.

The 1 st curable composition or the 2 nd curable composition may contain a (meth) acrylic compound other than the urethane (meth) acrylate compound and the polyfunctional (meth) acrylate compound. Examples of such (meth) acrylic compounds include epoxy (meth) acrylate compounds; a carboxyl-modified epoxy (meth) acrylate compound; a polyester (meth) acrylate compound; monofunctional (meth) acrylate compounds, and the like. These may be used alone or in combination of two or more.

The monofunctional (meth) acrylate compound may be a monomer, an oligomer or a polymer, and among them, a monofunctional (meth) acrylate monomer may be preferably used. Examples of the monofunctional (meth) acrylate monomer include methyl (meth) acrylate, ethyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, isobutyl (meth) acrylate, t-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, isononyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 2-hydroxybutyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 2-hydroxy-3-phenoxypropyl (meth) acrylate, trimethylolpropane mono (meth) acrylate, pentaerythritol mono (meth) acrylate, ethylcarbitol (meth) acrylate, 2-phenoxyethyl (meth) acrylate, phenoxypolyethylene glycol (meth) acrylate, 2- (N, N-dimethylamino) ethyl (meth) acrylate, 2-carboxyethyl (meth) acrylate, 1- [2- (meth) acryloyloxyethyl ] phthalate, 1- [2- (meth) acryloyloxyethyl ] hexahydrophthalate, 1- [2- (meth) acryloyloxyethyl ] succinate, 4- [2- (meth) acryloyloxyethyl ] trimellitate, tetrahydrofurfuryl (meth) acrylate, dicyclopentanyl (meth) acrylate, dicyclopentenyl (meth) acrylate, and the like. The monofunctional (meth) acrylate monomer may be used alone or in combination of two or more.

When the 1 st or 2 nd curable composition contains a monofunctional (meth) acrylate compound, the content of the monofunctional (meth) acrylate compound is preferably 5 parts by mass or more, more preferably 20 parts by mass or more, and preferably 50 parts by mass or less, relative to 100 parts by mass of the solid components of the curable composition. When the content of the monofunctional (meth) acrylate compound is within the above range, the coating property is improved from the viewpoint of adjusting the viscosity of the curable composition.

From the viewpoint of improving curability, at least one (preferably both) of the 1 st curable composition and the 2 nd curable composition preferably contains a radical polymerization initiator. The radical polymerization initiator is not particularly limited as long as it can initiate curing of the curable compound by irradiation with active energy rays such as visible light rays, ultraviolet rays, X-rays, and electron rays, and specific examples thereof include acetophenone-based initiators such as acetophenone, 3-methylacetophenone, benzildimethylketal, 1- (4-isopropylphenyl) -2-hydroxy-2-methylpropan-1-one, 2-methyl-1- [4- (methylthio) phenyl ] -2-morpholinopropan-1-one, and 2-hydroxy-2-methyl-1-phenylpropan-1-one; benzophenone-based initiators such as benzophenone, 4-chlorobenzophenone and 4, 4' -diaminobenzophenone; alkylphenone-based initiators such as 2, 2-dimethoxy-1, 2-diphenylethane-1-one and 1-hydroxy-cyclohexyl-phenyl-ketone; benzoin ether-based initiators such as benzoin propyl ether and benzoin ethyl ether; thioxanthone initiators such as 4-isopropylthioxanthone; acylphosphine oxide-based initiators such as bis (2,4, 6-trimethylbenzoyl) -phenylphosphine oxide; and xanthone, fluorenone, camphorquinone, benzaldehyde, anthraquinone, etc. These radical polymerization initiators may be used alone or in combination of two or more.

When the 1 st or 2 nd curable composition contains a radical polymerization initiator, the content of the radical polymerization initiator is preferably 1 to 10 parts by mass, more preferably 2 to 8 parts by mass, per 100 parts by mass of the solid components of the curable compound. When the content of the radical polymerization initiator is not less than the above lower limit, the polymerization initiating ability can be sufficiently exhibited, and the curability can be improved. On the other hand, when the content of the polymerization initiator is not more than the above upper limit, the radical polymerization initiator is less likely to remain, and the decrease in visible light transmittance and the like are more likely to be suppressed.

The 1 st curable composition or the 2 nd curable composition may contain, if necessary, other additives other than the radical polymerization initiator, for example, an ultraviolet absorber, an antistatic agent, a stabilizer, an antioxidant, a colorant, a surface conditioner, and the like. Other additives may be used alone or in combination of two or more. The content of the other additives is preferably about 0.1 to 20% by mass relative to the mass of the solid components of the curable composition.

The 1 st curable composition or the 2 nd curable composition can be prepared by mixing and stirring a (meth) acrylic compound and additives added as needed. In addition, in order to improve the coatability, the viscosity can be adjusted by adding a solvent to the 1 st curable composition or the 2 nd curable composition.

The solvent may be any solvent as long as it can dissolve the components constituting the 1 st curable composition or the 2 nd curable composition, and for example, the solvent may be selected from aliphatic hydrocarbons such as hexane and octane; aromatic hydrocarbons such as toluene and xylene; alcohol solvents such as ethanol, 1-propanol, isopropanol, and 1-butanol; ketones such as methyl ethyl ketone and methyl isobutyl ketone; esters such as ethyl acetate, butyl acetate, isobutyl acetate, etc.; glycol ether solvents such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, diethylene glycol monoethyl ether, propylene glycol monomethyl ether, and propylene glycol monoethyl ether; ethylene glycol monomethyl ether acetate, propylene glycol monomethyl ether acetate, and other esterified glycol ether solvents are suitably selected and used. These solvents may be used alone or in combination of two or more. The type and content of the solvent are appropriately selected depending on the type, content, shape, coating method, thickness of the resin layer, and the like of the components contained in the 1 st curable composition or the 2 nd curable composition, and for example, the content of the solvent is preferably 3 to 1000 parts by mass, more preferably 5 to 100 parts by mass, and further preferably 7 to 80 parts by mass with respect to 100 parts by mass of the solid components of the curable composition.

In one embodiment of the present invention, the 1 st resin layer is obtained by applying the 1 st curable composition to a polarizer or a release film and curing the composition. The 2 nd resin layer is obtained by applying the 2 nd curable composition to a substrate, a release film or an alignment film and curing the composition.

Examples of the coating method of the 1 st curable composition or the 2 nd curable composition include the coating methods exemplified in the column of < polarizer >. The curable composition is preferably cured by irradiating the composition with active energy rays to polymerize a polymerizable component such as a (meth) acrylic compound contained in the composition. The active energy ray is appropriately selected depending on the kind of polymerizable component such as a (meth) acrylic compound, the kind of radical polymerization initiator, the amount thereof, and the like. Specific examples thereof include 1 or more active energy rays selected from the group consisting of visible light, ultraviolet light, infrared light, X-rays, α -rays, β -rays, and γ -rays. Among them, ultraviolet light is preferable because the progress of the polymerization reaction can be easily controlled and an apparatus widely used in the art can be used as the photopolymerization apparatus. As the light source of the active energy ray, the light sources exemplified in the column of < polarizer > can be cited. The ultraviolet irradiation intensity, irradiation time, and accumulated light amount may be appropriately within the range of the ultraviolet irradiation intensity, irradiation time, and accumulated light amount exemplified in the column of < polarizer >.

The thickness of the 1 st resin layer and the 2 nd resin layer is preferably 0.1 to 10 μm, more preferably 0.2 to 5 μm, and still more preferably 0.3 to 3 μm. When the thickness of the 1 st resin layer or the 2 nd resin layer is within the above range, the adhesion between the 1 st resin layer and the polarizer and the adhesion between the 2 nd resin layer and the alignment film are easily improved, and the flexibility is easily improved.

< polarizing film >

As described above, the polarizing film of the present invention has excellent adhesion between layers and can exhibit excellent bendability. In addition, in a preferred embodiment, since the polarizing plate has excellent heat resistance in addition to adhesiveness and bendability, diffusion of the dichroic dye contained in the polarizing plate can be effectively suppressed even in a high-temperature environment. Therefore, the polarizing film of the present invention can be suitably used for display devices such as organic EL display devices and touch panel display devices.

The method for producing a polarizing film of the present invention is not particularly limited as long as the 1 st resin layer, the polarizer, the alignment film, and the 2 nd resin layer can be sequentially laminated, and examples thereof include a method comprising the following steps: forming a 2 nd resin layer, forming an orientation film on the 2 nd resin layer, forming a polarizer on the orientation film to obtain a laminate in which the 2 nd resin layer, the orientation film and the polarizer are sequentially laminated, coating or laminating a1 st curable composition on the polarizer surface of the laminate, and curing the 1 st curable composition.

In a preferred embodiment of the present invention, the polarizing film of the present invention can be produced by a method comprising the steps of: the method for producing a multilayer structure comprises applying a1 st curable composition to the polarizer surface of a multilayer structure comprising a 2 nd resin layer, an alignment film and a polarizer laminated on a release film, and curing the 1 st curable composition by irradiating the 1 st curable composition with an active energy ray from the 1 st curable composition side to obtain a multilayer structure comprising the release film, the 2 nd resin layer, the alignment film, the polarizer and the 1 st resin layer in this order, and peeling the release film from the multilayer structure.

In a preferred embodiment of the present invention, the polarizing film of the present invention can be produced by a method comprising the steps of: a laminate comprising a release film, a1 st resin layer, a polarizer, an alignment film, and a 2 nd resin layer laminated in this order is obtained by laminating the 1 st curable composition formed on the release film with the polarizer surface of a laminate comprising the 2 nd resin layer, the alignment film, and the polarizer laminated in this order, and irradiating the release film side with an active energy ray to cure the 1 st curable composition, and the release film is peeled from the laminate.

The polarizing film of the present invention may be a polarizing film in which a1 st resin layer, a polarizer, an alignment film, and a 2 nd resin layer are laminated in this order, and a functional layer may be included on the surface of the 1 st resin layer opposite to the polarizer side, the surface of the 2 nd resin layer opposite to the alignment film side, or between the layers, as long as the effects of the present invention are not impaired. Examples of the functional layer include an ultraviolet absorbing layer, a hard coat layer, a primer layer, a gas barrier layer, a color tone adjusting layer, a refractive index adjusting layer, an antireflection layer, an antistatic layer, an adhesive layer, and an adhesive layer. These functional layers may be used alone or in combination of two or more.

[ polarizing plate ]

The polarizing film of the present invention may be combined with a retardation film to form a polarizing plate. That is, the polarizing plate of the present invention includes the polarizing film and the retardation film. The retardation film may be laminated on the surface of the 1 st resin layer or the surface of the 2 nd resin layer of the polarizing film via an adhesive layer or a pressure-sensitive adhesive layer, for example. It is preferable that the retardation film and the polarizing film (polarizer) are laminated so that the slow axis (optical axis) of the retardation film and the absorption axis of the polarizing film are substantially 45 °. The retardation film and the polarizing film (polarizer) are laminated so that the slow axis (optical axis) thereof is substantially 45 ° to the absorption axis thereof, whereby the polarizing film can function as an elliptical polarizing plate. The angle is substantially 45 °, and is usually in the range of 45 ± 5 °.

In the polarizing plate, the retardation film preferably satisfies the following formula (X):

100≤Re(550)≤180 (X)

[ in the formula, Re (550) represents an in-plane retardation value at a wavelength of 550nm ].

When the retardation film has the in-plane retardation value represented by the above (X), it functions as a so-called λ/4 plate. The above formula (X) is preferably 100 nm. ltoreq. Re (550). ltoreq.180 nm, and more preferably 120 nm. ltoreq. Re (550).ltoreq.160 nm.

Further, the retardation film preferably satisfies the following formula (Y):

Re(450)/Re(550)<1 (Y)

in the formula, Re (450) and Re (550) represent in-plane retardation values at wavelengths of 450nm and 550nm, respectively.

The retardation film satisfying the above formula (Y) has so-called reverse wavelength dispersibility, and exhibits excellent polarizing performance. The value of Re (450)/Re (550) is preferably 0.93 or less, more preferably 0.88 or less, further preferably 0.86 or less, preferably 0.80 or more, more preferably 0.82 or more.

The retardation film may be a stretched film that imparts a retardation by stretching a polymer, and is preferably composed of a polymerizable liquid crystal composition containing a polymer of a polymerizable liquid crystal compound (hereinafter also referred to as a polymerizable liquid crystal composition (B)) from the viewpoint of reducing the thickness of the polarizing plate.

In the retardation film, the polymerizable liquid crystal compound is usually polymerized in an aligned state. The polymerizable liquid crystal compound (hereinafter, also referred to as "polymerizable liquid crystal compound (B)") forming the retardation film is a liquid crystal compound having a polymerizable functional group, particularly a photopolymerizable functional group. The photopolymerizable functional group means a group that can participate in a polymerization reaction by an active radical, an acid, or the like generated from a photopolymerization initiator. Examples of the photopolymerizable functional group include a vinyl group, a vinyloxy group, a 1-chloroethenyl group, an isopropenyl group, a 4-vinylphenyl group, an acryloyloxy group, a methacryloyloxy group, an oxetanyl group, and an oxetanyl group. Among them, acryloyloxy, methacryloyloxy, vinyloxy, oxetanyl and oxetanyl groups are preferable, and acryloyloxy group is more preferable. The liquid crystal may be a thermotropic liquid crystal or a lyotropic liquid crystal, and the phase-ordered structure may be a nematic liquid crystal or a smectic liquid crystal. The polymerizable liquid crystal compound may be used alone in 1 kind, or may be used in combination with 2 or more kinds.

The polymerizable liquid crystal compound (B) may be a compound satisfying all of the following (I) to (IV) from the viewpoints of ease of film formation and imparting retardation represented by the formula (Y).

(I) Is a compound having thermotropic liquid crystallinity;

(II) has pi electrons in the longitudinal direction (a) of the polymerizable liquid crystal compound.

(III) has pi electrons in a direction [ crossing direction (b) ] crossing the longitudinal direction (a).

(IV) the total of pi electrons present in the major axis direction (a) is denoted by N (pi a), the total of molecular weights present in the major axis direction is denoted by N (aa), and the pi electron density in the major axis direction (a) of the polymerizable liquid crystal compound is defined by the following formula (i):

D(πa)＝N(πa)/N(Aa) (i)

the pi electron density in the cross direction (b) of the polymerizable liquid crystal compound is defined by the following formula (ii) where N (pi b) represents the total of pi electrons present in the cross direction (b), N (ab) represents the total of molecular weights present in the cross direction (b), and N (ab) represents the total of molecular weights present in the cross direction (b):

D(πb)＝N(πb)/N(Ab) (ii)

the D (π a) and the D (π b) are in a relationship of 0 ≦ D (π a)/D (π b) ≦ 1 [ i.e., a π electron density in the cross direction (b) is greater than a π electron density in the long axis direction (a) ].

The polymerizable liquid crystal compound (B) satisfying all of the above (I) to (IV) is applied to, for example, an alignment film formed by rubbing treatment, and heated to a phase transition temperature or higher, thereby forming a nematic phase. The nematic phase formed by aligning the polymerizable liquid crystal compound (B) is generally aligned so that the long axis directions of the polymerizable liquid crystal compound are parallel to each other, and the long axis direction is the alignment direction of the nematic phase.

The polymerizable liquid crystal compound (B) having the above characteristics usually exhibits reverse wavelength dispersibility in many cases. Specific examples of the compound satisfying the characteristics (I) to (IV) include compounds represented by the following formula (II).

The compounds represented by the above formula (II) may be used alone or in combination of two or more.

In the formula (II), Ar represents a divalent aromatic group which may have a substituent. The aromatic group as used herein means a group having a planar cyclic structure and having a number of pi electrons of [4n +2] according to the houcker rule. Here, n represents an integer. When a ring structure is formed by including a heteroatom such as-N ═ S-, it includes a case where the ring structure satisfies the houcker rule including a non-covalent electron pair on the heteroatom and has aromaticity. The divalent aromatic group preferably contains at least 1 or more of a nitrogen atom, an oxygen atom, and a sulfur atom.

In the formula (II), G¹And G²Each independently represents a divalent aromatic group or a divalent alicyclic hydrocarbon group. Here, the hydrogen atom contained in the divalent aromatic group or the divalent alicyclic hydrocarbon group may be substituted with a halogen atom, an alkyl group having 1 to 4 carbon atoms, a fluoroalkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a cyano group, or a nitro group, and the carbon atom constituting the divalent aromatic group or the divalent alicyclic hydrocarbon group may be replaced with an oxygen atom, a sulfur atom, or a nitrogen atom.

In the formula (II), L¹、L²、B¹And B²Each independently is a single bond or a divalent linking group.

In the formula (II), k and l independently represent an integer of 0 to 3, and satisfy the relationship of 1. ltoreq. k + l. Here, in the case of 2. ltoreq. k + l, B¹And B²、G¹And G²The components may be the same or different from each other.

In the formula (II), E¹And E²Each independently represents an alkanediyl group having 1 to 17 carbon atoms, wherein a hydrogen atom contained in the alkanediyl group may be substituted with a halogen atom, and a-CH group contained in the alkanediyl group₂-can be replaced by-O-, -S-, -Si-. P¹And P²Independently of each other, represents a polymerizable group or a hydrogen atom, and at least 1 is a polymerizable group.

In the formula (II), G¹And G²Each independently is preferably a1, 4-phenylene group (phenylenediyl group) which may be substituted with at least 1 substituent selected from the group consisting of a halogen atom and an alkyl group having 1 to 4 carbon atoms, or a1, 4-cyclohexanediyl group which may be substituted with at least 1 substituent selected from the group consisting of a halogen atom and an alkyl group having 1 to 4 carbon atoms, more preferably a1, 4-phenylene group substituted with a methyl group, an unsubstituted 1, 4-phenylene group, or an unsubstituted 1, 4-trans-cyclohexanediyl group, and particularly preferably an unsubstituted 1, 4-phenylene group or an unsubstituted 1, 4-trans-cyclohexanediyl group. In addition, it is preferable that a plurality of G's are present¹And G²At least 1 of them is a divalent alicyclic hydrocarbon group, and is more preferably bonded to L¹Or L²Bonded G¹And G²At least 1 of them is a divalent alicyclic hydrocarbon group.

In the formula (II), L¹And L²Independently of each other, preferably a single bond, an alkylene group having 1 to 4 carbon atoms, -O-, -S-, -R-^a1OR^a2-、-R^a3COOR^a4-、-R^a5OCOR^a6-、-R^a7OC＝OOR^a8-、-N＝N-、-CR^c＝CR^d-, or-C.ident.C-. Here, R^a1～R^a8Each independently represents a single bond or an alkylene group having 1 to 4 carbon atoms, R^cAnd R^dRepresents an alkyl group having 1 to 4 carbon atoms or a hydrogen atom. L is¹And L²Each independently more preferably a single bond, -OR^a2-1-、-CH₂-、-CH₂CH₂-、-COOR^a4-1-, or-OCOR^a6-1-. Here, R^a2-1、R^a4-1、R^a6-1Each independently represents a single bond, -CH₂-、-CH₂CH₂-any of the above. L is¹And L²Further preferably a single bond, -O-, -CH₂CH₂-、-COO-、-COOCH₂CH₂-, or-OCO-.

In a preferred embodiment of the present invention, G in the formula (II) may be used¹And G²At least 1 of which is a divalent alicyclic hydrocarbon group, which may be substituted by a divalent aromatic group Ar and L as-COO-¹And/or L²A polymerizable liquid crystal compound obtained by bonding.

In the formula (II), B¹And B²Independently of each other, preferably a single bond, an alkylene group having 1 to 4 carbon atoms, -O-, -S-, -R-^a9OR^a10-、-R^a11COOR^a12-、-R^a13OCOR^a14-, or-R^a15OC＝OOR^a16-. Here, R^a9～R^a16Each independently represents a single bond or an alkylene group having 1 to 4 carbon atoms. B is¹And B²Each independently more preferably a single bond, -OR^a10-1-、-CH₂-、-CH₂CH₂-、-COOR^a12-1-, or-OCOR^a14-1-. Here, R^a10-1、R^a12-1、R^a14-1Each independently represents a single bond, -CH₂-、-CH₂CH₂-any of the above. B is¹And B²Further preferably a single bond, -O-, -CH₂CH₂-、-COO-、-COOCH₂CH₂-, -OCO-, or-OCOCH₂CH₂-。

In formula (II), k and l are preferably in the range of 2 ≦ k + l ≦ 6, preferably k + l ═ 4, more preferably k ═ 2 and l ═ 2, from the viewpoint of exhibiting reverse wavelength dispersibility. When k is 2 and l is 2, a symmetrical structure is obtained, and therefore, it is more preferable.

In the formula (II), E¹And E²Each independently is preferably an alkanediyl group having 1 to 17 carbon atoms, and more preferably an alkanediyl group having 4 to 12 carbon atoms.

In the formula (II), as P¹Or P²Examples of the polymerizable group include an epoxy group, a vinyl group, a vinyloxy group, a 1-chloroethenyl group, an isopropenyl group, a 4-vinylphenyl group, an acryloyloxy group, a methacryloyloxy group, an oxetanyl group, and an oxetanyl group. Of these, acryloyloxy, methacryloyloxy, vinyloxy, oxetanyl and oxetanyl groups are preferred, and acryloyloxy groups are more preferred.

In the formula (II), Ar preferably has at least 1 selected from an aromatic hydrocarbon ring which may have a substituent, an aromatic heterocyclic ring which may have a substituent, and an electron-withdrawing group. Examples of the aromatic hydrocarbon ring include a benzene ring, a naphthalene ring, and an anthracene ring, and a benzene ring and a naphthalene ring are preferable. Examples of the aromatic heterocyclic ring include a furan ring, a benzofuran ring, a pyrrole ring, an indole ring, a thiophene ring, a benzothiophene ring, a pyridine ring, a pyrazine ring, a pyrimidine ring, a triazole ring, a triazine ring, a pyrroline ring, an imidazole ring, a pyrazole ring, a thiazole ring, a benzothiazole ring, a thienothiazole ring, an oxazole ring, a benzoxazole ring, and a phenanthroline ring. Of these, a thiazole ring, a benzothiazole ring, or a benzofuran ring is preferable, and a benzothiazolyl group is more preferable. When Ar contains a nitrogen atom, the nitrogen atom preferably has pi electrons.

In the formula (II), the total number N of pi electrons contained in the divalent aromatic group represented by Ar_πPreferably 8 or more, more preferably 10 or more, further preferably 14 or more, and particularly preferably 16 or more. Further, it is preferably 30 or less, more preferably 26 or less, and further preferably 24 or less.

Examples of the aromatic group represented by Ar include groups represented by the following formulae (Ar-1) to (Ar-23).

In the formulae (Ar-1) to (Ar-23), symbol represents a connecting part, Z⁰、Z¹And Z²Each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, a cyano group, a nitro group, an alkylsulfinyl group having 1 to 12 carbon atoms, an alkylsulfonyl group having 1 to 12 carbon atoms, a carboxyl group, a fluoroalkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alkylthio group having 1 to 12 carbon atoms, an N-alkylamino group having 1 to 12 carbon atoms, an N, N-dialkylamino group having 2 to 12 carbon atoms, an N-alkylsulfamoyl group having 1 to 12 carbon atoms or an N, N-dialkylsulfamoyl group having 2 to 12 carbon atoms.

In the formulae (Ar-1) to (Ar-23), Q¹And Q²Each independently represents-CR^2’R^3’-、-S-、-NH-、-NR^2’-, -CO-or O-, R^2’And R^3’Each independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.

In formulae (Ar-1) to (Ar-23), J¹And J²Each independently represents a carbon atom or a nitrogen atom.

In the formulae (Ar-1) to (Ar-23), Y¹、Y²And Y³Each independently represents an optionally substituted aromatic hydrocarbon group or aromatic heterocyclic group.

In the formulae (Ar-1) to (Ar-23), W¹And W²Each independently represents a hydrogen atom, a cyano group, a methyl group or a halogen atom, and m represents an integer of 0 to 6.

As Y¹、Y²And Y³The aromatic hydrocarbon group in (1) includes aromatic hydrocarbon groups having 6 to 20 carbon atoms such as a phenyl group, a naphthyl group, an anthryl group, a phenanthryl group, and a biphenyl group, preferably a phenyl group and a naphthyl group, and more preferably a phenyl group. Examples of the aromatic heterocyclic group include an aromatic heterocyclic group having 4 to 20 carbon atoms containing at least one hetero atom such as a nitrogen atom, an oxygen atom, a sulfur atom and the like, such as a furyl group, a pyrrolyl group, a thienyl group, a pyridyl group, a thiazolyl group and a benzothiazolyl group.

Y¹And Y²Each independently may be a polycyclic aromatic hydrocarbon group or a polycyclic aromatic heterocyclic group which may be substituted. The polycyclic aromatic hydrocarbon group means a fused polycyclic aromatic hydrocarbon group or a group derived from an aromatic ring assembly. The polycyclic aromatic heterocyclic group means a fused polycyclic aromatic heterocyclic group or a group derived from an aromatic ring assembly.

In the formulae (Ar-1) to (Ar-23), Z⁰、Z¹And Z²Each independently preferably represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, a cyano group, a nitro group, an alkoxy group having 1 to 12 carbon atoms, Z⁰More preferably a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, a cyano group, Z¹And Z²More preferably a hydrogen atom, a fluorine atom, a chlorine atom, a methyl group or a cyano group.

In the formulae (Ar-1) to (Ar-23), Q¹And Q²preferably-NH-, -S-, -NR^2’-、-O-，R^2’Preferably a hydrogen atom. Among them, particularly preferred are-S-, -O-, -NH-.

Among the formulae (Ar-1) to (Ar-23), the formulae (Ar-6) and (Ar-7) are preferred from the viewpoint of molecular stability.

In formulae (Ar-17) to (Ar-23), Y¹Nitrogen atom and Z which may be bonded thereto⁰Together form an aromatic heterocyclic group. As aromaticsExamples of the heterocyclic group include the aromatic heterocyclic groups described above as the aromatic heterocyclic group that Ar may have, and examples thereof include a pyrrole ring, an imidazole ring, a pyrroline ring, a pyridine ring, a pyrazine ring, a pyrimidine ring, an indole ring, a quinoline ring, an isoquinoline ring, a purine ring, and a pyrrolidine ring. The aromatic heterocyclic group may have a substituent. In addition, Y¹Nitrogen atom and Z which may be bonded thereto⁰Together form the above-mentioned optionally substituted polycyclic aromatic hydrocarbon group or polycyclic aromatic heterocyclic group. Examples thereof include a benzofuran ring, a benzothiazole ring, and a benzoxazole ring. The compound represented by the formula (II) can be produced, for example, by the method described in jp 2010-31223 a.

The content of the polymerizable liquid crystal compound (B) in the polymerizable liquid crystal composition (B) constituting the retardation film is, for example, 70 to 99.5 parts by mass, preferably 80 to 99 parts by mass, and more preferably 90 to 98 parts by mass, based on 100 parts by mass of the solid content of the polymerizable liquid crystal composition (B). When the content is within the above range, the orientation of the retardation film tends to be high. The solid component herein means the total amount of components remaining after removing volatile components such as a solvent from the polymerizable liquid crystal composition (B).

The polymerizable liquid crystal composition (B) may contain a polymerization initiator for initiating a polymerization reaction of the polymerizable liquid crystal compound (B). The polymerization initiator may be suitably selected from polymerization initiators conventionally used in this field, and may be a thermal polymerization initiator or a photopolymerization initiator, and is preferably a photopolymerization initiator in view of initiating a polymerization reaction under relatively low temperature conditions. Preferably, the same photopolymerization initiators as those mentioned above as the photopolymerization initiators usable in the composition for forming a polarizer can be used. The polymerizable liquid crystal composition (B) may contain, if necessary, a photosensitizing agent, a leveling agent, and additives exemplified as additives contained in the composition for forming a polarizing plate. Examples of the photosensitizing agent and the leveling agent include those similar to those exemplified above as the photosensitizing agent and the leveling agent that can be used in the composition for forming a polarizing plate.

The polymerizable liquid crystal composition (B) is prepared by, for example, mixing and stirring the polymerizable liquid crystal compound (B) and, if necessary, a polymerization initiator, additives and the like. In addition, in order to improve the coatability, a solvent may be added to the polymerizable liquid crystal composition (B) to adjust the viscosity. As the solvent, the solvents exemplified above as the solvent contained in the composition for forming a polarizer can be cited.

The retardation film can be obtained by: the polymerizable liquid crystal composition (B) is applied to a substrate or an alignment film, the solvent is removed by drying, and the polymerizable liquid crystal compound (B) in the obtained coating film is cured by heating and/or active energy rays. As the alignment film, the same alignment films as those exemplified above as alignment films usable in producing the polarizer of the present invention can be cited.

The solvent used in the composition for forming a retardation film, the method for applying the composition for forming a retardation film, the curing conditions by active energy rays, and the like can be the same as those employed in the method for producing a polarizer of the present invention.

The thickness of the retardation film is suitably selected depending on the display device to be used, and is preferably 0.1 to 10 μm, more preferably 1 to 5 μm, and still more preferably 1 to 3 μm from the viewpoint of the reduction in thickness and flexibility.

The polarizing plate of the present invention may include other layers than the polarizing film, the retardation film, and the adhesive layer or the adhesive layer, for example, a protective film. In a preferred embodiment, the polarizing film and the retardation film are bonded to each other with an adhesive layer or an adhesive layer interposed therebetween.

The thickness of the polarizing plate of the present invention is preferably 1 to 100 μm, more preferably 2 to 70 μm, and still more preferably 3 to 60 μm from the viewpoint of flexibility and visibility of the display device.

The polarizing film or polarizing plate of the present invention may be provided with a front panel. Fig. 1 is a schematic cross-sectional view of a layer structure of a polarizing film with a front panel according to an embodiment of the present invention. The polarizing film 1 with a front panel has a front panel 3 formed on the 1 st resin layer 4 of the polarizing film 2. The polarizing film 2 is formed by laminating a1 st resin layer 4, a polarizer 5, an alignment film 6, and a 2 nd resin layer 7 in this order from the front panel 3 side. The polarizing film with a front panel 1 can be provided with surface hardness and light resistance by including the front panel. In the front-panel-attached polarizing film 1, an adhesive layer or an adhesive layer may be formed between the front panel 3 and the 1 st resin layer 4.

Fig. 2 is a schematic cross-sectional view of the layer structure of the polarizing plate with a front plate according to one embodiment of the present invention. The polarizing plate with front panel 8 has a front panel 3 formed on a polarizing plate 9. The polarizing plate 9 is formed by laminating a1 st resin layer 4, a polarizer 5, an alignment film 6, a 2 nd resin layer 7, and a retardation film 10 in this order from the front panel 3 side. The polarizing plate with front plate 8 can be provided with surface hardness and light resistance by including the front plate. In the front-panel-attached polarizing plate 8, an adhesive layer or an adhesive layer may be formed between the front panel 3 and the 1 st resin layer 4 and/or between the 2 nd resin layer 7 and the retardation film 10. In fig. 1 and 2, the size, ratio, and the like of each layer are appropriately changed to facilitate the view of the drawings.

Fig. 3 is a schematic cross-sectional view of the layer structure of the polarizing film with a front panel according to another embodiment of the present invention. The polarizing film 11 with a front panel has a front panel 3 formed on the 2 nd resin layer 7 of the polarizing film 2. The polarizing film 2 is formed by laminating a 2 nd resin layer 7, an alignment film 6, a polarizer 5, and a1 st resin layer 4 in this order from the front panel 3 side. The polarizing film 11 with a front panel can be provided with surface hardness and light resistance by providing the front panel. The front-panel-attached polarizing film 11 may have an adhesive layer or an adhesive layer formed between the front panel 3 and the 2 nd resin layer 7.

Fig. 4 is a schematic cross-sectional view of the layer structure of the polarizing plate with a front plate according to another embodiment of the present invention.

The polarizing plate 12 with a front panel has a front panel 3 formed on a polarizing plate 13. The polarizing plate 13 is formed by laminating a 2 nd resin layer 7, an alignment film 6, a polarizer 5, a1 st resin layer 4, and a retardation film 10 in this order from the front panel 3 side. The polarizing plate 13 with a front panel can be provided with surface hardness and light resistance by including the front panel. The front-panel-attached polarizing plate 13 may have an adhesive layer or an adhesive layer formed between the front panel 3 and the 2 nd resin layer 7 and/or between the 1 st resin layer 4 and the retardation film 10. In fig. 3 and 4, the size, ratio, and the like of each layer are appropriately changed to facilitate the view of the drawings.

< display device >

The polarizing film of the present invention or the above polarizing plate may be applied to a display device. The display device can be obtained by, for example, laminating the polarizing film of the present invention or the polarizing plate on the surface of the display device via an adhesive layer or an adhesive layer. The display device is a device having a display mechanism, and includes a light emitting element or a light emitting device as a light emitting source. Examples of the display device include a liquid crystal display device, an organic Electroluminescence (EL) display device, an inorganic Electroluminescence (EL) display device, a touch panel display device, an electron emission display device (a field emission display device (FED, etc.), a surface conduction field emission display device (SED)), electronic paper (a display device using electronic ink or an electrophoretic element), a plasma display device, a projection display device (a Grating Light Valve (GLV) display device, a display device having a Digital Micromirror Device (DMD), and a piezoelectric ceramic display device. The liquid crystal display device includes all of a transmission type liquid crystal display device, a semi-transmission type liquid crystal display device, a reflection type liquid crystal display device, a direct-view type liquid crystal display device, a projection type liquid crystal display device, and the like. These display devices may be display devices that display two-dimensional images or may be stereoscopic display devices that display three-dimensional images. In particular, the display device of the present invention is preferably an organic EL display device or a touch panel display device, and particularly preferably an organic EL display device.

Examples

The present invention will be described in more detail below with reference to examples and comparative examples, but the present invention is not limited to these examples. Hereinafter, unless otherwise specified, the amounts used, parts of contents and% are based on mass.

< evaluation of adhesion >

The polarizing films obtained in examples and comparative examples were subjected to a peel test after the surface of the 2 nd resin layer was bonded to glass via a pressure-sensitive adhesive and a transparent tape (product name: Cellotape; manufactured by Nichiban) was attached to the surface of the 1 st resin layer opposite to the glass surface, and the adhesiveness of the polarizing film was evaluated. A case where the peeling phenomenon could be observed in the polarizing film was taken as "x", and a case where the peeling phenomenon could not be observed was taken as "o".

< evaluation of Heat resistance >

The polarization degree Py and the monomer transmittance Ty of the polarizing films obtained in examples and comparative examples were measured in the following manner. The transmittance (Ta) in the transmission axis direction and the transmittance (Tb) in the absorption axis direction were measured by a two-beam method using a device equipped with a polarizer-equipped folder in a spectrophotometer (UV-3150, manufactured by Shimadzu corporation) at a wavelength of 380nm to 780 nm. In this folder, the reference side is provided with a mesh intercepting 50% of the light.

The monomer transmittance and the degree of polarization at each wavelength were calculated using the following formulae (formula 1) and (formula 2), and further the visibility corrected monomer transmittance (Ty) and the visibility corrected degree of polarization (Py) were calculated by performing visibility correction in accordance with a 2-degree field of view (C light source) of JIS Z8701.

Monomer transmittance Ty (%) - (Ta + Tb)/2 (formula 1)

Degree of polarization Py (%) - (Ta-Tb)/(Ta + Tb) × 100 (formula 2)

After the polarizing films obtained in examples and comparative examples were heated at 85 ℃ for 240 hours under a dry condition, the polarization degree Py and the monomer transmittance Ty of the polarizing film were measured again, and the amount of change Δ Py between before and after the heat resistance test (which is Py after the heat resistance test — Py before the heat resistance test) and the amount of change Δ Ty between before and after the heat resistance test (which is Ty after the heat resistance test — Ty before the heat resistance test) were calculated.

< evaluation of bendability >

The flexibility was evaluated by the following method using the general coating test method described in JIS-K-5600-5-1, namely the flexibility resistance (cylindrical mandrel method).

The polarizing films obtained in examples and comparative examples were cut into 25mm × 200mm squares, and a bending test was performed by winding the cut films around a mandrel bar having a diameter of 2mm (bending radius R is 1mm) so that the cured layer of the 1 st resin layer forming composition was positioned outside the cut films under conditions of a temperature of 25 ℃ and a relative humidity of 55% RH using a cylindrical mandrel method bending resistance tester type II (manufactured by TP technical research corporation). Using the film after the test, the generation of cracks was observed by visual observation with transmitted light under illumination in a dark room environment, and as a result, the case where cracks could be observed was judged to be "x", and the case where cracks could not be observed was judged to be "o".

< film thickness of each layer >

The thicknesses of the polarizer, the alignment film, the 1 st resin layer and the 2 nd resin layer were measured by a laser microscope (OLS 3000, manufactured by Olympus corporation).

Production examples 1 to 7

< preparation of compositions (A) to (G) for Forming resin layer >

The components shown in table 1 were mixed and stirred at 50 ℃ for 4 hours to obtain compositions (a) to (G) for forming a resin layer.

Production example 8

< preparation of composition for Forming resin layer (H) >

The following components were mixed and stirred at 23 ℃ for 4 hours to obtain a composition (H) for forming a resin layer.

Celloxide 2021P: 70 parts of 3, 4-epoxycyclohexylmethyl-3, 4-epoxycyclohexanecarboxylate (manufactured by Daicel chemical Co., Ltd.)

30 parts of 2-ethylhexyl glycidyl ether

CPI-100P: 2.5 parts of a 50% solution of triarylsulfonium hexafluorophosphate in propylene carbonate (manufactured by San-Apro Co., Ltd.)

SH 710: 0.25 part of silicone leveling agent (manufactured by Dow Corning Toray Co., Ltd.)

Production example 9

< preparation of composition (I) for Forming resin layer >

The following components were mixed and stirred at 23 ℃ for 4 hours to obtain a composition (I) for forming a resin layer.

Celloxide 2021P: 32.5 parts of 3, 4-epoxycyclohexylmethyl-3, 4-epoxycyclohexanecarboxylate (manufactured by Daicel chemical Co., Ltd.)

EHPE 3150: 17.5 parts of 1, 2-epoxy-4- (2-oxirane) cyclohexane adduct of 2, 2-bis (hydroxymethyl) -1-butanol (manufactured by Daicel chemical Co., Ltd.)

OXT-221: 50 parts of bis (3-ethyl-3-oxetanylmethyl) ether (manufactured by Toyo Seiya Kabushiki Kaisha)

CPI-100P: 2.5 parts of a 50% solution of triarylsulfonium hexafluorophosphate in propylene carbonate (manufactured by San-Apro Co., Ltd.)

SH 710: 0.25 part of silicone leveling agent (manufactured by Dow Corning Toray Co., Ltd.)

Production example 10

< preparation of composition (J) for Forming resin layer >

An acetoacetylated modified polyvinyl alcohol resin (GOHSEFIMER Z200, manufactured by Nippon synthetic chemical industries, Ltd., degree of saponification: 98.5 mol% or more) was dissolved in pure water by stirring at 90 ℃ for 4 hours to prepare a 5 wt% aqueous solution. The polyvinyl alcohol resin aqueous solution and a 10 wt% aqueous solution of sodium glyoxylate were mixed with an acetoacetyl group-modified polyvinyl alcohol resin: the weight ratio of solid components of sodium glyoxylate is 1: 0.1, and further diluted with pure water so that the weight ratio of the solid content of the polyvinyl alcohol resin to 100 parts of water became 3.0, to prepare a composition (J) for forming a resin layer.

[ Table 1]

The components in table 1 are shown below.

Multifunctional acrylate monomer (1): the number of atoms of the chain connecting the branching point closest to the (meth) acryloyl group in the branched structure to the (meth) acryloyl group was 5 by oxiranylation (6) dipentaerythritol hexaacrylate ("NK ESTER A-DPH-6E" manufactured by NONSHOM CHEMICAL Co., Ltd.).

Multifunctional acrylate monomer (2): the number of atoms of the chain connecting the branching point closest to the (meth) acryloyl group in the branched structure to the (meth) acryloyl group was 8 by oxiranation (12) dipentaerythritol hexaacrylate ("NK ESTER A-DPH-12E" manufactured by NONSHOM CHEMICAL CO., LTD.).

Urethane acrylate polymer (1): urethane acrylate (manufactured by Nippon synthetic chemical industry Co., Ltd. "purple light UV-7650B") having a functional group number of 4 to 5, a weight average molecular weight Mw of 2300, and a functional group number per unit molecular weight of 19.6X 10^-4。

Urethane acrylate polymer (2): urethane acrylate ("purple UV-3310B" manufactured by Nippon synthetic chemical industry Co., Ltd.), 2 functional groups, 5000 weight average molecular weight Mw, and 4.0X 10 functional groups per unit molecular weight^-4。

Urethane acrylate polymer (3): urethane acrylate ("purple UV-6640B" manufactured by Nippon synthetic chemical industry Co., Ltd.), a functional group number of 2, a weight average molecular weight Mw of 5000, and a functional group number per unit molecular weight of 4.0X 10^-4。

Urethane acrylate polymer (4): urethane acrylate ("purple UV-7510B" manufactured by Nippon synthetic chemical industry Co., Ltd.), 3 number of functional groups, 3500 weight-average molecular weight Mw, and 8.6X 10 number of functional groups per unit molecular weight^-4。

Urethane acrylate polymer (5): urethane acrylate ("purple UV-7550B" manufactured by Nippon synthetic chemical industry Co., Ltd.), 3 functional groups, 2400 weight average molecular weight Mw, and 12.5X 10 functional groups per unit molecular weight^-4。

Radical polymerization initiator (1): phenylbis (2,4, 6-trimethylbenzoyl) phosphine oxide (product of BASF corporation, "Irgacure 819")

Radical polymerization initiator (2): 1-Hydroxycyclohexyl phenyl ketone (product of BASF corporation, "Irgacure 184")

Solvent (1): methyl ethyl ketone

Production example 8

< preparation of composition for Forming polarizing film >

The following components were mixed and stirred at 80 ℃ for 1 hour to obtain a composition for forming a polarizing film. As the dichroic dye, an azo dye described in examples of Japanese patent application laid-open No. 2013-101328 is used.

Polymerizable liquid crystal compound:

dichroic pigment:

an azo pigment;

photopolymerization initiator:

6 parts of 2-dimethylamino-2-benzyl-1- (4-morpholinophenyl) butan-1-one (Irgacure 369; manufactured by Ciba Specialty Chemicals Co., Ltd.)

Leveling agent:

polyacrylate Compound (BYK-361N; BYK-Chemie Co., Ltd.) 1.2 parts

Solvent:

400 portions of o-xylene

[ example 1]

(1) Preparation of No. 2 resin layer

The release-treated surface of the polyethylene terephthalate film (SP-PLR 382050 manufactured by LINTEC corporation) (release film) subjected to the release treatment was subjected to corona treatment, and then a composition (A) for forming a resin layer as a 2 nd curable composition was applied by a bar coating method (# 230 mm/s) to coat the release-treated surface and the compositionThe exposure amount was adjusted to 500mJ/cm by using a UV irradiation apparatus (SPOT CURE SP-7; manufactured by Ushio Motor Co., Ltd.)²The resin layer-attached release film having the 2 nd resin layer formed on the surface thereof was obtained by irradiating ultraviolet rays (365nm basis) to the coating film layer of the resin layer-forming composition. The thickness of the 2 nd resin layer was 1.5. mu.m.

(2) Production of photo-alignment film

(i) Preparation of composition for forming photo-alignment film

The following photo-alignment polymer and the following solvent were mixed at the following ratio, and the resulting mixture was stirred at 80 ℃ for 1 hour to obtain a composition for forming a photo-alignment film. The photo-alignment polymer described below was prepared by the method described in synthetic example 1 of jp 2013-033249 a, and had a number average molecular weight of 28200 and an Mw/Mn of 1.82.

Photo-alignment polymer:

solvent:

98 portions of o-xylene

(ii) Formation of photo-alignment film

Next, the surface of the 2 nd resin layer of the release film with a resin layer was subjected to corona treatment, and then a composition for forming a photo-alignment film was applied and dried at 120 ℃. The dried film was irradiated with polarized UV light to form a photoalignment film, and a laminate a having a release film, a 2 nd resin layer, and a photoalignment film in this order was obtained. The polarized UV light treatment was carried out under the condition that the intensity measured at a wavelength of 365nm was 100mJ using a UV irradiation apparatus (SPOT CURE SP-7; manufactured by Ushio Motor Co., Ltd.). The thickness of the photo-alignment film was 100 nm.

(3) Method for manufacturing polaroid

The surface of the photoalignment film of laminate A obtained in the above-described manner was coated with a composition for forming a polarizing film by a bar coating method (# 930 mm/s), and the coating was dried by heating at 120 ℃ in a drying oven for 1 minuteThe polymerizable liquid crystal compound is thereby brought into a liquid phase, and then cooled to room temperature, whereby the polymerizable liquid crystal compound is brought into a smectic liquid crystal state. Next, an exposure amount was set to 1000mJ/cm using a UV irradiation apparatus (SPOT CURE SP-7; manufactured by Ushio Motor Co., Ltd.)²Ultraviolet rays (365nm basis) are irradiated to the layer formed of the composition for forming a polarizing film, thereby polymerizing the polymerizable liquid crystal compound contained in the dry film while maintaining the smectic liquid crystal state of the polymerizable liquid crystal compound, and forming a polarizer (polarizing film) from the dry film. The thickness of the polarizer was 2.3 μm. In this manner, a laminate B having the release film, the 2 nd resin layer, the photo-alignment film, and the polarizer in this order was obtained. As a result of X-ray diffraction measurement using an X-ray diffraction device X' Pert PRO MPD (manufactured by Spectris corporation) in the same manner, a sharp diffraction peak (bragg peak) having a full width at half maximum (FWHM) of about 0.17 ° was obtained near 2 θ of about 20.2 °. An order period (d) determined from the peak position of aboutIt was confirmed that a structure reflecting a higher order smectic phase was formed.

(4) Preparation of the No. 1 resin layer

The surface of the polarizer of the laminate B obtained in the above-described manner was subjected to corona treatment, and then a resin layer-forming composition (A) as a1 st curable composition was applied again by a bar coating method (# 230 mm/s) and the exposure amount was set to 500mJ/cm using a UV irradiation apparatus (SPOT CURE SP-7; manufactured by Ushio Motor Co., Ltd.)²The coating layer of the resin layer-forming composition was irradiated with ultraviolet rays (365nm basis), thereby obtaining a laminate C having a release film, a 2 nd resin layer, a photo-alignment film, a polarizer, and a1 st resin layer in this order. Next, the release film is peeled off to obtain a polarizing film having a 2 nd resin layer, a photo alignment film, a polarizer, and a1 st resin layer in this order. The thickness of the 1 st resin layer was 1.5 μm.

Examples 2 to 7 and comparative examples 1 and 2

Polarizing films of examples 2 to 7 and comparative examples 1 and 2 were obtained in the same manner as in example 1 except that the resin layer forming compositions (B) to (I) were used instead of the resin layer forming composition (a) as shown in table 2.

The polarizing films obtained in examples 1 to 7 and comparative examples 1 and 2 were evaluated for adhesiveness and bendability. The results are shown in Table 2.

Comparative example 3

(1) Preparation of No. 2 resin layer

The release-treated surface of the polyethylene terephthalate film (SP-PLR 382050 manufactured by LINTEC corporation) (release film) subjected to the release treatment was subjected to corona treatment, and then a resin layer-forming composition (J) as a 2 nd curable composition was applied by a bar coating method (#3030mm/s), followed by drying at 100 ℃ for 1 minute, thereby obtaining a release film with a resin layer in which a 2 nd resin layer was formed on the surface of the release film. The thickness of the 2 nd resin layer was 1.5. mu.m.

(2) Production of photo-alignment film

Next, the surface of the 2 nd resin layer of the release film with a resin layer was subjected to corona treatment, and then a composition for forming a photo-alignment film was applied and dried at 120 ℃. The dried film was irradiated with polarized UV light to form a photoalignment film, and a laminate K including a release film, a 2 nd resin layer, and the photoalignment film in this order was obtained. The polarized UV light treatment was carried out under the condition that the intensity measured at a wavelength of 365nm was 100mJ using a UV irradiation apparatus (SPOT CURE SP-7; manufactured by Ushio Motor Co., Ltd.). The thickness of the photo-alignment film was 100 nm.

(3) Method for manufacturing polaroid

The surface of the photoalignment film of the laminate K obtained in the above-described manner was coated with a composition for forming a polarizing film by a bar coating method (# 930 mm/s), and was dried by heating in a drying oven at 120 ℃ for 1 minute, whereby the polymerizable liquid crystal compound phase was changed to a liquid phase, and then cooled to room temperature, so that the polymerizable liquid crystal compound phase was changed to a smectic liquid crystal state. Next, an exposure amount was set to 1000mJ/cm using a UV irradiation apparatus (SPOT CURE SP-7; manufactured by Ushio Motor Co., Ltd.)²Irradiating ultraviolet ray (365nm standard) to the layer formed by the composition for forming polarizing film, thereby dryingThe polymerizable liquid crystal compound contained in the film is polymerized while maintaining the smectic liquid crystal state of the polymerizable liquid crystal compound, and a polarizer (polarizing film) is formed from the dried film. The thickness of the polarizer was 2.3 μm. In this manner, a laminate L having the release film, the 2 nd resin layer, the photo-alignment film, and the polarizer in this order was obtained.

(4) Preparation of the No. 1 resin layer

The surface of the polarizer of the laminate L obtained in the above manner was subjected to corona treatment, and then, the resin layer forming composition (L) as the 1 st curable composition was applied again by a bar coating method (#3030mm/s) and dried at 100 ℃ for 1 minute, thereby obtaining a laminate M having a release film, a 2 nd resin layer, a photo-alignment film, a polarizer, and a1 st resin layer in this order. Subsequently, the release film was peeled off, thereby obtaining a polarizing film having a 2 nd resin layer, a photo-alignment film, a polarizer, and a1 st resin layer in this order. The thickness of the 1 st resin layer was 1.5 μm.

The polarizing film obtained in comparative example 3 was evaluated for adhesiveness and bendability.

The results are shown in Table 2.

[ Table 2]

	1 st resin layer	2 nd resin layer	Evaluation of adhesion	Evaluation of bendability
					Example 1	(A)	(A)	○	○
Example 2	(B)	(B)	○	○
					Example 3	(C)	(C)	○	○
Example 4	(D)	(D)	○	○
					Example 5	(E)	(E)	○	○
Example 6	(F)	(F)	○	○
					Example 7	(G)	(G)	○	○
Comparative example 1	(H)	(H)	×	○
					Comparative example 2	(I)	(I)	×	○
Comparative example 3	(J)	(J)	×	○

The polarizing film obtained in example 7 was evaluated for heat resistance. As a result, Δ Py was-1.5 and Δ Ty was-0.2.

As shown in table 2, the polarizing films obtained in examples 1 to 7 and comparative examples 1 to 3 were evaluated for adhesiveness as o, and excellent interlayer adhesiveness was confirmed. Further, the results of the bendability evaluation were also o, and it was found that the bendability was also excellent. On the other hand, the polarizing films obtained in comparative examples 1 to 3 had poor adhesion as a result of evaluation of adhesion.

In addition, it is understood that the polarizing film obtained in example 7 has Δ Py and Δ Ty close to 0 and also has excellent heat resistance.

Description of the reference numerals

1. 11 … polarizing film with front panel

2 … polarizing film

3 … front panel

4 … resin layer No. 1

5 … polarizer

6 … oriented film

7 … No. 2 resin layer

8. 12 … polarizing plate with front panel

9. 13 … polarizing plate

10 … phase difference film