Polarizing film, polarizing plate, optical laminate, elliptically polarizing plate, organic EL display device, and flexible image display device

Abstract

A polarizing film which is a polarizing film comprising a photo-alignment film and a polarizing sheet adjacent to the photo-alignment film, the aforementioned photo-alignment film being formed of a polymer comprising a structural unit having a photoreactive group and a structural unit having a polymerizable group, the aforementioned polarizing sheet being a cured product of a liquid crystal composition comprising a liquid crystal compound and a dichroic dye, and comprising a structural unit having a polymerizable group from the liquid crystal compound or the dichroic dye.

Description

Technical Field

[0001] This invention relates to polarizing films, polarizing plates containing the same, optical laminates, elliptical polarizing plates, organic EL display devices, and flexible image display devices. Background Technology

[0002] Polarizing plates are used in various image display panels, such as liquid crystal display panels and organic electroluminescent (organic EL) display panels. As such polarizing plates, in addition to polarizing plates that are obtained by oriented adsorption of dichroic pigments such as iodine in a polyvinyl alcohol-based resin film, polarizing films that are obtained by polymerizing a polymeric liquid crystal compound by coating a light-adjusting film onto a substrate are also known.

[0003] Patent documents

[0004] Patent Document 1: Japanese Patent Application Publication No. 2013-33249 Summary of the Invention

[0005] The problem that the invention aims to solve

[0006] Polarizing films formed by coating layers of liquid crystal compounds are often used in the form of a laminate having a polarizer and an alignment film for forming the polarizer. In such polarizing films, a decrease in the adhesion between the alignment film and the polarizer can affect the optical properties of the polarizing film.

[0007] Therefore, the object of the present invention is to provide a polarizing film with excellent adhesion between the polarizer and the alignment film.

[0008] Methods for solving problems

[0009] The inventors of this application conducted in-depth research to solve the aforementioned problems, resulting in the completion of this invention. Specifically, this invention provides the following preferred embodiments.

[0010] [1] A polarizing film, which comprises a light alignment film and a polarizer adjacent to the light alignment film.

[0011] The aforementioned photo-alignment film is formed from a polymer containing structural units with photoreactive groups and structural units with polymerizable groups.

[0012] The aforementioned polarizer is a cured liquid crystal composition comprising a liquid crystal compound and a dichroic pigment, and contains structural units with polymerizable groups derived from the liquid crystal compound or the dichroic pigment.

[0013] [2] As described in [1], the photoreactive group is a group that can undergo dimerization or isomerization.

[0014] [3] The polarizing film according to [1] or [2], wherein the polymer forming the photo-alignment film further contains a structural unit having a carboxyl group.

[0015] [4] The polarizing film according to any one of [1] to [3], wherein the polymer forming the photo-alignment film has a weight-average molecular weight of 20,000 or more and 150,000 or less.

[0016] [5] The polarizing film according to any one of [1] to [4], wherein the polymer forming the photo-alignment film has a repeating unit represented by formula (II).

[0017] [Chemical formula 1]

[0018]

[0019] [In formula (II),

[0020] Ma, Mb, and Mc each independently represent a molecular chain forming the main chain of the aforementioned polymer;

[0021] m, n, and l represent the molar fractions of the aforementioned polymer, and in any case, 0 < m < 1, 0 < n < 1, and 0 < l < 1;

[0022] SPCRa, SPCRb, and SPCRc each independently represent a divalent group;

[0023] Ring A, ring B, and ring C are each independently an unsubstituted or substituted alicyclic hydrocarbon or an unsubstituted or substituted aromatic ring;

[0024] X is a single bond, an alkylene chain having 1 to 10 carbon atoms, or a cycloalkylene chain having 3 to 8 carbon atoms;

[0025] Y is -O-CO-CH=CH2- (any connecting bond can be bonded to ring B), or -N=N-;

[0026] Z is selected from the group consisting of a single bond; an alkylene chain having 1 to 10 carbon atoms that is unsubstituted or substituted with a hydroxyl group and / or a carbonyl group; a cycloalkylene chain having 3 to 8 carbon atoms; -O-; -COO-; and combinations thereof;

[0027] R

[0028] ,

[0026] ,

[0027] ,

[0024] , 2 ,

[0029] ,

[0025] , , , , , 1 , is an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a phenyl group having at least one substituent selected from a cyano group and a halogen atom;

[0028] R 2 is -CW=CH2, or -V-CW=CH2 (where W is a hydrogen atom or a methyl group, and V is -O-CO- or -CO-)

[0029] [6] The polarizing film as described in any one of [1] to [5], wherein the dichroic pigment comprises an azo pigment.

[0030] [7] The polarizing film as described in any one of [1] to [6], wherein the polarizing film comprises a polymer of a polymeric liquid crystal compound.

[0031] [8] The polarizing film as described in any one of [1] to [7], wherein the polarizer exhibits a Bragg peak in X-ray diffraction measurements.

[0032] [9] A polarizing plate comprising a polarizing film as described in any one of [1] to [8] and a substrate disposed on the light orientation film side of the polarizing film.

[0033]

[10] An optical laminate comprising [9] a polarizing plate and a layer bonded to the polarizer side of the polarizing plate via an adhesive layer.

[0034]

[11] An elliptical polarizing plate comprising a polarizing film as described in any one of [1] to [8] and a phase difference layer having a 1 / 4 wavelength plate function.

[0035]

[12] An organic EL display device comprising the elliptical polarizing plate described in

[11] .

[0036]

[13] A flexible image display device comprising the elliptical polarizing plate described in

[11] .

[0037]

[14] The flexible image display device as described in

[13] further includes a window and a touch sensor.

[0038] Invention Effects

[0039] According to the present invention, a polarizing film with excellent adhesion between the polarizer and the alignment film can be provided. Detailed Implementation

[0040] The embodiments of the present invention will now be described in detail. It should be noted that the scope of the present invention is not limited to the embodiments described herein, and various modifications can be made without departing from the spirit of the invention.

[0041] [Polarizing film]

[0042] The polarizing film of the present invention comprises a photoalignment film and a polarizer adjacent to the photoalignment film, and is substantially formed by the photoalignment film and the polarizer. It should be noted that, in this specification, the laminate formed by the photoalignment film and the polarizer stacked adjacent to the photoalignment film is referred to as a polarizing film. When a substrate is disposed on the side of the photoalignment film in addition to the photoalignment film and the polarizer adjacent to the photoalignment film, the laminate formed by the layers from the substrate to the polarizer is referred to as a polarizing plate.

[0043] The photo-alignment film constituting the polarizing film of the present invention is formed from a polymer comprising structural units having photoreactive groups and structural units having polymerizable groups, preferably from a copolymer comprising structural units having photoreactive groups and structural units having polymerizable groups.

[0044] In the polymer that forms the photoalignment film, structural units with photoreactive groups help to impart liquid crystal alignment capability through the action of light, while structural units with polymerizable groups help to improve the adhesion to the polarizer formed on the photoalignment film.

[0045] In one embodiment of the present invention, the structural unit having a photoreactive group (hereinafter also referred to as "structural unit (i)") is derived from a monomer having at least one photoreactive group. A photoreactive group refers to a group that generates liquid crystal orientation capability through light irradiation. Specifically, it refers to a group capable of undergoing a light reaction, such as dimerization, isomerization, or photodecomposition, which becomes the origin of liquid crystal orientation capability through light irradiation, thereby inducing the orientation of polymer molecules. The structural unit (i) may have one or more photoreactive groups.

[0046] A dimerization reaction refers to an addition reaction between two groups, typically forming a ring structure, caused by the action of light. The groups capable of undergoing this dimerization reaction are those containing carbon-carbon double bonds (C=C bonds) or carbon-oxygen double bonds (C=O bonds), which are induced by light irradiation. Examples include groups with cinnamoyl structures, chalcone structures, coumarin structures, benzophenone structures, and anthracene structures. From the viewpoint of requiring less polarized light irradiation for photo-orientation and readily obtaining photo-orientation films with excellent thermal and time stability, groups with cinnamoyl and chalcone structures are preferred, and groups with cinnamoyl structures are more preferred.

[0047] Isomerization is a reaction in which a single compound undergoes stereoisomerization, structural isomerization, or other isomerization through the action of light. The functional groups capable of undergoing this isomerization reaction are those containing nitrogen-nitrogen double bonds (N=N) or carbon-carbon double bonds (C=C), which are induced by light irradiation. Examples include groups with an azobenzene structure, groups with a piracene structure, groups with a hydrazono-β-keto ester structure (backbone), and groups with a spiropyran structure (backbone).

[0048] The so-called photodecomposition reaction refers to the reaction in which polymer chains are broken by the action of light, thus exhibiting anisotropy.

[0049] In this invention, the photoreactive group is preferably a group capable of undergoing a dimerization reaction or a group capable of undergoing an isomerization reaction, and more preferably a group capable of undergoing a dimerization reaction. Groups capable of undergoing a dimerization reaction and groups capable of undergoing an isomerization reaction are preferred from the viewpoints of reactivity and cost. Particularly regarding reactivity, it is important that the photoreactive group reacts without causing the structural units having polymerizable groups (described later) to react.

[0050] In one embodiment of the present invention, the structural unit having a polymerizable group (hereinafter also referred to as "structural unit (ii)") is derived from a monomer having at least one polymerizable group. A polymerizable group refers to a group that participates in a polymerization reaction; examples include thermally polymerizable groups and photopolymerizable groups, but the polymerizable group included in the structural unit having a polymerizable group is preferably a photopolymerizable group. The structural unit (ii) may have one type of polymerizable group or two or more types.

[0051] Examples of polymerizable groups constituting structural unit (ii) include vinyl, vinyloxy, 1-chlorovinyl, isopropenyl, 4-vinylphenyl, (meth)acryloyl, (meth)acryloyloxy, oxetylpropyl, oxetylbutyl, etc.

[0052] From the viewpoint of ease of reaction control and improved adhesion to the polarizer, (meth)acryloyl, (meth)acryloyloxy, vinyloxy, oxetylpropyl, and oxetylbutyl are preferred, more preferably (meth)acryloyl and (meth)acryloyloxy, and even more preferably (meth)acryloyloxy. It should be noted that in this specification, "(meth)acryloyl" refers to methacryloyl and acryloyl.

[0053] If the photoalignment film is formed from a polymer containing structural units (ii) having polymeric groups, a polarizing film with excellent adhesion to the polarizer stacked adjacent to it can be formed. One reason for this effect is that during the formation of the polarizer, which is a cured liquid crystal composition, the polymeric groups contained in the photoalignment film react simultaneously with the polymerization reaction of the liquid crystal compound, dichroic pigment, or other liquid crystal material used to form the polarizer, and can bond with the polymeric groups possessed by the liquid crystal compound or dichroic pigment or other liquid crystal material forming the polarizer. Therefore, when the dichroic pigment or polymeric liquid crystal compound forming the polarizer has the same polymeric groups as the aforementioned polymer, it is easier to improve the adhesion between the polarizer and the photoalignment film.

[0054] In the present invention, the polymer forming the photo-alignment film has an unreacted polymerizable group as structural unit (ii). Structural unit (ii) may also be a structural unit derived from a monomer having such a polymerizable group. In the aforementioned polymer, at least a part of the polymerizable groups possessed by the aforementioned monomers forming the polymer exist in an unreacted state. In the structural unit derived from a monomer having the aforementioned polymerizable group, all the polymerizable groups may exist in an unreacted state. When unreacted polymerizable groups are present in the polymer in a sufficient proportion, during the formation of a polarizing plate fabricated after forming a polarizing film, polymerizable groups capable of reacting simultaneously with the polymerization reaction of the liquid crystalline substance used for forming the polarizing plate exist in the photo-alignment film in a sufficient amount, and thus it is easy to improve the adhesion between the photo-alignment film and the polarizing plate.

[0055] From the aspect of easily forming an alignment film exhibiting high liquid crystal alignment ability and excellent adhesion to a polarizing plate, in the present invention, the polymer forming the photo-alignment film is preferably a polymer having structural unit (i) and structural unit (ii) as structural units, and more preferably a polymer in which a photoreactive group and a polymerizable group are respectively located at the ends of the side chains of the polymer.

[0056] As a polymer containing structural unit (i) and structural unit (ii), for example, a polymer obtained by copolymerizing a monomer derived from structural unit (i) and a monomer derived from structural unit (ii), or introducing the polymerizable group possessed by structural unit (ii) into a (co)polymer containing structural unit (i) can be cited.

[0057] As the above polymer, for example, a polymer having a structure represented by the following formula (I) as a repeating unit can be cited.

[0058] [Chemical formula 2]

[0059]

[0060] [In formula (I),

[0061] Mb and Mc each independently represent a molecular chain forming the main chain of the polymer;

[0062] n and l represent the molar fractions of the copolymer, and in any case, 0 < n < 1 and 0 < l < 1;

[0063] SPCRb and SPCRc each independently represent a divalent group;

[0064] Ring B and ring C each independently represent an unsubstituted or substituted alicyclic hydrocarbon or an unsubstituted or substituted aromatic ring;

[0065] Y can be -O-CO-CH=CH2- (any linker bond can be combined with a ring B bond) or -N=N-;

[0066] Z is selected from the following groups: free single bonds; alkylene chains with 1 to 10 carbon atoms that are unsubstituted or substituted with hydroxyl and / or carbonyl groups; cycloalkylene chains with 3 to 8 carbon atoms; -O-; -COO-; and combinations thereof.

[0067] R 1 It is an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a phenyl group having at least one substituent selected from cyano and halogen atoms;

[0068] R 2 For example, -CW=CH2 or -V-CW=CH2 (where W is a hydrogen atom or a methyl group, and V is -O-CO- or -CO-).

[0069] In formula (I), for example, the structures of Mb and Mc can be: (meth)acrylate units represented by formula (M-1) or (M-2); (meth)acrylamide units represented by formula (M-3) or (M-4); vinyl ether units represented by formula (M-5) or (M-6); units selected from the group consisting of (meth)styrene units represented by formula (M-7) or (M-8) and vinyl ester units represented by formula (M-9) or (M-10).

[0070] In formulas (M-1) to (M-10), * denotes the linking bond with SPCRb and SPCRc. In formula (I), the polymer backbone is preferably composed of units selected from the aforementioned group, and more preferably composed of units selected from the group consisting of (meth)acrylate units and (meth)acrylamide units. It should be noted that the term "polymer backbone" here refers to the longest molecular chain in the copolymer.

[0071] [Chemical Formula 3]

[0072]

[0073] In formula (I), SPCRb and SPCRc can be, for example, carbonyloxy group (ester bond), oxygen atom (ether bond), imide group (imide bond), carbonyl imino group (amide bond), imino carbonyl imino group (carbamate bond), divalent aliphatic hydrocarbon group that may have substituents and divalent aromatic hydrocarbon group that may have substituents, as well as divalent groups formed by combining them.

[0074] Specific examples of divalent aromatic hydrocarbon groups that may have substituents include phenylene, 2-methoxy-1,4-phenylene, 3-methoxy-1,4-phenylene, 2-ethoxy-1,4-phenylene, 3-ethoxy-1,4-phenylene, and 2,3,5-trimethoxy-1,4-phenylene. Among these, SPCRb and SPCRc are each preferably aliphatic hydrocarbon groups, and more preferably alkane diesters having 1 to 11 carbon atoms that may have substituents. It should be noted that as said alkane diesters, examples include methylene, ethylene, propylene, 1,4-butylene (tramethylene group), 1,5-pentylene, 1,6-hexylene, 1,7-heptylene, 1,8-octylene, 1,9-nonylene, 1,10-decylene, and 1,11-undecamethylene (undecamethylene group), which can be linear or branched. Furthermore, the alkane diene may have substituents. These substituents may be, for example, alkoxy groups having 1 to 4 carbon atoms.

[0075] In equation (I), rings B and C can be represented, for example, by the ring structures represented by equations (X-1) to (X-5).

[0076] [Chemical Formula 4]

[0077]

[0078] In the above structure, X 1 ~X 38 Each is independently a hydrogen atom, alkyl group, alkoxy group, halogen atom, or cyano group. As X 1 ~X 38 The alkyl group represented can be alkyl groups having 1 to 4 carbon atoms, as X. 1 ~X 38 The alkoxy group represented can be exemplified by alkoxy groups having 1 to 4 carbon atoms. X 1 ~X 38 Each is preferably a hydrogen atom or a halogen atom, more preferably a hydrogen atom.

[0079] Ring B and ring C are preferably ring structures represented by formula (X-1) or formula (X-5), and more preferably ring structures represented by formula (X-1).

[0080] In equation (I), R 1 Preferably, it is an alkyl group having 1 to 6 carbon atoms, or a phenyl group having at least one substituent selected from cyano and halogen atoms; more preferably, it is an alkyl group having 1 to 6 carbon atoms, or a phenyl group substituted with a cyano group; and even more preferably, it is an alkyl group having 1 to 6 carbon atoms. As R 1 The alkyl group is preferably an alkyl group having 1 to 4 carbon atoms, and more preferably a methyl group.

[0081] In equation (I), R 2 Preferably, it is -CW=CH2 or -V-CW=CH2 (where W is a hydrogen atom or a methyl group, and V is -O-CO- or -CO-).

[0082] In formula (I), n and l are the mole fractions of structural unit (i) and structural unit (ii) relative to all structural units of the polymer forming the photo-aligned film, and preferably satisfy the relationships 0.1 ≤ n ≤ 0.9 and 0.1 ≤ l ≤ 0.9. From the viewpoint of orientation and adhesion, it is preferable that the mole fractions of structural unit (i) and structural unit (ii) are within the above ranges.

[0083] In equation (I), l preferably satisfies the relationship 0.1≤l≤0.5, and more preferably satisfies the relationship 0.1≤l≤0.3.

[0084] Equation (I) schematically represents monomers of derived structural unit (i) and monomers of derived structural unit (ii) in a molar ratio of n:1, and does not imply that the monomers of derived structural unit (i) and monomers of derived structural unit (ii) must be alternately bonded to form a copolymer. That is, Equation (I) can include any copolymer obtained by polymerizing monomers of derived structural unit (i) and monomers of derived structural unit (ii) in a molar ratio of n:1, such as alternating, block, random, grafted, etc.

[0085] In one aspect of the present invention, the polymer forming the photo-alignment film preferably includes, in addition to structural units (i) and structural units (ii), structural units having carboxyl groups (hereinafter also referred to as "structural units (iii)").

[0086] When the photo-alignment film includes structural unit (iii), the polymer forming the photo-alignment film is preferably a polymer having structural units (i), (ii), and (iii), and more preferably a polymer in which the photoreactive group, polymerizable group, and carboxyl group are located at the ends of the polymer side chains. By giving the polymer such a structure, it is easier to form an alignment film with better adhesion to the polarizer.

[0087] As a polymer comprising structural unit (i), structural unit (ii), and structural unit (iii), examples include polymers obtained by copolymerizing monomers of derived structural unit (i), monomers of derived structural unit (ii), and monomers of derived structural unit (iii), or by introducing polymerizable groups of structural unit (ii) into a (co)polymer comprising structural unit (i) and / or structural unit (iii). As such polymers, examples include copolymers having a repeating structure represented by the following formula (II).

[0088] [Chemical Formula 5]

[0089]

[0090] [In formula (II),

[0091] Ma, Mb and Mc each independently represent a molecular chain forming the main chain of the aforementioned polymer;

[0092] m, n and l represent the molar fractions of the aforementioned polymer, and in any case, 0 < m < 1, 0 < n < 1 and 0 < l < 1;

[0093] SPCRa, SPCRb and SPCRc each independently represent a divalent group;

[0094] Ring A, ring B and ring C are each independently an unsubstituted or substituted alicyclic hydrocarbon or an unsubstituted or substituted aromatic ring;

[0095] X is a single bond, an alkylene chain having 1 to 10 carbon atoms, or a cycloalkylene chain having 3 to 8 carbon atoms;

[0096] Y is -O-CO-CH=CH2- (any bonding site can be bonded to ring B), or -N=N-;

[0097] Z is selected from the group consisting of a single bond; an alkylene chain having 1 to 10 carbon atoms that is unsubstituted or substituted with a hydroxyl group and / or a carbonyl group; a cycloalkylene chain having 3 to 8 carbon atoms; -O-; -COO-; and combinations thereof;

[0098] R 1 is an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a phenyl group having at least one substituent selected from a cyano group and a halogen atom;

[0099] R 2 is -CW=CH2, or -V-CW=CH2 (where W is a hydrogen atom or a methyl group, and V is -O-CO- or -CO-).]

[0100] In formula (II), as the structures of Ma, Mb and Mc, the same structures as those exemplified as the structures of Mb and Mc in formula (I) can be cited.

[0101] In formula (II), as SPCRa, SPCRb and SPCRc, the same structures as those exemplified as the structures of SPCRb and SPCRc in formula (I) can be cited.

[0102] In formula (II), as ring A, ring B and ring C, the same structures as those exemplified as the structures of ring B and ring C in formula (I) can be cited.

[0103] In formula (II), ring A is preferably a ring structure represented by formula (X-1), and rings B and C are preferably ring structures represented by formula (X-1) or (X-5), more preferably ring structures represented by formula (X-1).

[0104] As R in equation (II) 1 and R 2 Examples of R in equation (I) can be cited. 1 and R 2 The structure is the same as the structure shown in the example.

[0105] In formula (II), m, n, and l represent the mole fractions (m+n+l=1) of structural units (iii), (i), and (ii) relative to all structural units of the polymer forming the photo-aligned film. Preferably, these fractions satisfy the relationships 0.1≤m≤0.8, 0.1≤n≤0.5, and 0.1≤l≤0.5, and more preferably, they satisfy the relationships 0.3≤m≤0.8, 0.1≤n≤0.3, and 0.1≤l≤0.3. From the viewpoint of orientation and adhesion, it is preferable that the mole fractions of structural units (i), (ii), and (iii) are within the above ranges.

[0106] Equation (II) schematically represents monomers of derivative structural unit (i), derivative structural unit (ii), and derivative structural unit (iii) in a molar ratio of n:l:m. It does not imply that the monomers of derivative structural unit (i), derivative structural unit (ii), and derivative structural unit (iii) must be alternately bonded to form a copolymer. That is, Equation (I) can include copolymers obtained by polymerizing monomers of derivative structural unit (i), derivative structural unit (ii), and derivative structural unit (iii) in a molar ratio of n:l:m, such as alternating, block, random, grafted, etc.

[0107] In one embodiment of the present invention, the polymer forming the photo-alignment film may also include other structural units (hereinafter also referred to as "other structural units") besides structural units (i), (ii) and (iii), as long as they do not affect the effects of the present invention.

[0108] The polymer forming the photoalignment film preferably has a weight-average molecular weight of 20,000 to 150,000. If the weight-average molecular weight is above the lower limit mentioned above, solvent resistance becomes good, and it is easy to obtain a photoalignment film that ensures high adhesion to the polarizer subsequently formed on the photoalignment film and exhibits high liquid crystal alignment capability. Furthermore, there is a tendency for the photoalignment film to exhibit the alignment properties seen when a liquid crystal composition (polarizer forming composition) is coated after its fabrication. Moreover, the inventors of this application have discovered that the higher the weight-average molecular weight of the polymer forming the photoalignment film becomes within the aforementioned range, the higher the liquid crystal alignment capability is exhibited, even when the processing temperature during photoalignment film formation is relatively high, excellent liquid crystal alignment capability can still be displayed. In this invention, the weight-average molecular weight of the polymer forming the photoalignment film is more preferably 30,000 or more, further preferably 50,000 or more, and even more preferably 140,000 or less, and even more preferably 130,000 or less.

[0109] It should be noted that the weight-average molecular weight of polymers can be determined and calculated using instruments such as gel permeation chromatography.

[0110] A polymer (hereinafter also referred to as "polymer (I')") comprising structural units (i) and (ii) forming a photo-oriented film can be manufactured by copolymerizing a specified amount of monomers of derived structural unit (i) and derivative structural unit (ii), monomers of derivative structural unit (iii) as needed, and monomers of other derived structural units under solvent-free conditions or in a solvent; or by introducing polymerizable groups of structural unit (ii) during the (co)polymerization of monomers of derivative structural unit (i) and / or monomers of derivative structural unit (iii). As a copolymerization method, methods conventionally known in the art can be used, such as chain polymerization (e.g., free radical polymerization, anionic polymerization, and cationic polymerization), and coordination polymerization. The polymerization conditions can be suitably determined according to the type and amount of monomers used to obtain a polymer with the desired molecular weight.

[0111] When polymerization is carried out in a solvent, known organic solvents can be used without particular limitation. Specific examples of solvents include alcohol solvents such as ethanol, propanol, and butanol; ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, and cyclopentanone; ester solvents such as ethyl acetate, butyl acetate, and propylene glycol monomethyl ether acetate; ether solvents such as diethyl ether and diethylene glycol dimethyl ether; hydrocarbon solvents such as hexane, cyclohexane, methylcyclohexane, toluene, and xylene; nitrile solvents such as acetonitrile; and amide solvents such as N-methyl-2-pyrrolidone and dimethylacetamide. Any one of these solvents can be used alone, or two or more can be used in combination.

[0112] During polymerization, polymerization initiators can be used. Suitable polymerization initiators can be selected from known initiators, such as azo-based initiators like azobisisobutyronitrile (AIBN), diethyl 2,2'-azobisisobutyrate (V-601), 2,2'-azobis(2,4-dimethylpentanonitrile), and dimethyl azobismethylpropionate; peroxide-based initiators like benzoyl peroxide, hydrogen peroxide, and lauroyl peroxide; and persulfate-based initiators like potassium persulfate and ammonium persulfate. These initiators can be used individually or in combination of two or more.

[0113] The polymerization conditions can be appropriately determined according to the type and amount of monomers used, in order to obtain a polymer with the desired molecular weight.

[0114] For example, the polymerization temperature can be appropriately set according to the type of monomer used, the type of polymerization solvent, the type of polymerization initiator, etc., preferably in the range of 40 to 150°C, and more preferably in the range of 50 to 120°C.

[0115] A photoalignment film can be obtained by coating a composition comprising a polymer (I') and a solvent that can typically dissolve the polymer (I') (hereinafter also referred to as a "photoalignment film forming composition") onto the surface of a substrate or the like where the photoalignment film will be formed, drying off the solvent, and then irradiating it with polarized light (preferably polarized UV light). The photoalignment film forming composition may also contain polymers such as polyvinyl alcohol and polyimide, and photosensitizers, without significantly impairing the properties of the photoalignment film.

[0116] The content of polymer (I') in the composition for forming a photo-aligned film can be appropriately adjusted according to the structure of the polymer (I'), the thickness of the target photo-aligned film, etc., and is preferably at least 0.1% by mass, more preferably in the range of 0.3% to 10% by mass, calculated based on solid components relative to the mass of the composition for forming a photo-aligned film. It should be noted that, in this specification, "solid components" refers to the total amount of components obtained by removing volatile components such as solvents from the composition for forming a photo-aligned film. Hereinafter, in compositions for forming polarizers, the same applies to the total amount of components obtained by removing volatile components such as solvents from the target composition.

[0117] The solvents used in the composition for forming the photo-aligned film can be appropriately selected according to the type of polymer (I') used. Examples 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 pentyl 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; chlorinated hydrocarbon solvents such as chloroform and chlorobenzene; and so on. Any one of these solvents can be used alone, or two or more can be used in combination.

[0118] Methods for coating a composition for forming a photo-aligned film onto a substrate include known methods such as spin coating, extrusion, gravure coating, die coating, bar coating, applicator coating, and printing methods such as flexographic printing.

[0119] Methods for removing solvent by drying include natural drying, ventilation drying, heating drying, and reduced pressure drying. This results in a dried coating film.

[0120] As a method of irradiating polarized light, it can be in the form of directly irradiating polarized light onto a dried coating obtained by removing the solvent from the composition for forming a photo-aligned film, or it can be in the form of irradiating polarized light from one side of a substrate on which the dried coating is formed, allowing the polarized light to pass through. Furthermore, it is particularly preferable that the polarized light is substantially parallel light. The wavelength of the irradiated polarized light is preferably in the wavelength region where the photoreactive groups of the polymer (I') can absorb light energy. Specifically, UV (ultraviolet light) in the wavelength range of 250 to 400 nm is particularly preferred.

[0121] Examples of light sources used for polarized light irradiation include xenon lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, metal halide lamps, KrF, ArF, and other ultraviolet lasers, with high-pressure mercury lamps, ultra-high-pressure mercury lamps, and metal halide lamps being more preferred. These lamps are preferred because of the high luminous intensity of ultraviolet light with a wavelength of 313 nm. Light from the aforementioned light sources can be irradiated by passing it through a suitable polarizer, thereby irradiating polarized light. As the polarizer, polarizing filters, polarizing prisms such as Glan-Thomson and Glan-Taylor, and wire-grid type polarizers can be used.

[0122] If the liquid crystal is masked during polarized light irradiation, multiple regions (patterns) with different liquid crystal orientations can be formed.

[0123] The thickness of the photo-alignment film is preferably 10–5000 nm, more preferably 10–1000 nm, and even more preferably 30–300 nm. If the thickness of the photo-alignment film is within the above range, it can exhibit good adhesion to the polarizer and exert an orientation constraint force, enabling the formation of a polarizer with a high orientation order.

[0124] The polarizer constituting the polarizing film of the present invention is a cured liquid crystal composition, i.e., a coating layer formed from the liquid crystal composition. The liquid crystal composition forming the polarizer (hereinafter also referred to as "polarizer forming composition") contains a liquid crystal compound and a dichroic pigment.

[0125] Dichroic pigments are pigments that exhibit different absorbance along their long axis and short axis. The dichroic pigments used in this invention are not particularly limited as long as they possess the aforementioned properties; they can be dyes or pigments. Furthermore, two or more dyes or pigments can be used in combination, or dyes and pigments can be used in combination. Additionally, dichroic pigments can exhibit polymerizability or liquid crystal properties.

[0126] In one embodiment of the present invention, the dichroic pigment preferably has a maximum absorption wavelength (λ) in the range of 300–700 nm. MAX The dichroic pigment is a dichroic pigment. Examples of such dichroic pigments include acridine pigments, oxazine pigments, cyanine pigments, naphthalene pigments, azo pigments, and anthraquinone pigments. Among these, azo pigments have high linearity and are therefore suitable for manufacturing polarizers with excellent polarizing properties. Therefore, in one aspect of the present invention, the dichroic pigment included in the polarizer-forming composition for forming the polarizer is preferably an azo pigment.

[0127] Examples of azo pigments include monoazo pigments, diazo pigments, triazo pigments, tetraazo pigments, and pizo pigments, with diazo pigments and triazo pigments being preferred. For example, compounds represented by formula (1) can be cited.

[0128] K 1 (-N=NK) 2 ) p -N=NK 3 (1)

[0129] In equation (1), K 1 and K 3 Each can be represented independently as a phenyl group that may have substituents, a naphthyl group that may have substituents, or a monovalent heterocyclic group that may have substituents. K 2 This indicates a p-phenylene group that may have substituents, a naphth-1,4-diyl group that may have substituents, or a divalent heterocyclic group that may have substituents. p represents an integer from 1 to 4. When p is an integer greater than 2, multiple K groups are represented. 2They can be the same or different. The -N=N- bond can be replaced by -C=C-, -COO-, -NHCO-, or -N=CH- bonds, as long as the region exhibits absorption in the visible light region.

[0130] In formula (1), a monovalent heterocyclic group can be, for example, a group obtained by removing one hydrogen atom from a heterocyclic compound such as quinoline, thiazole, benzothiazole, thienothiazole, imidazole, benzimidazole, oxazole, or benzoxazole. A divalent heterocyclic group can be, for example, a group obtained by removing two hydrogen atoms from the aforementioned heterocyclic compound.

[0131] As K in equation (1) 1 and K 3 The phenyl, naphthyl, and monovalent heterocyclic groups, as well as K 2 The p-phenylene, naphthalene-1,4-diyl, and divalent heterocyclic groups may optionally contain substituents, such as alkyl groups with 1 to 20 carbon atoms, alkyl groups with 1 to 20 carbon atoms having polymerizable groups, alkenyl groups with 1 to 4 carbon atoms; alkoxy groups with 1 to 20 carbon atoms such as methoxy, ethoxy, and butoxy; fluoroalkyl groups with 1 to 20 carbon atoms such as trifluoromethyl; cyano; nitro; halogen atoms; substituted or unsubstituted amino groups such as amino, diethylamino, and pyrrolidinyl (substituted amino groups refer to amino groups having one or two alkyl groups with 1 to 6 carbon atoms, amino groups having one or two alkyl groups with 1 to 6 carbon atoms, or amino groups formed by two substituted alkyl groups bonded together to form an alkane diene with 2 to 8 carbon atoms. Unsubstituted amino groups are -NH2). Examples of polymerizable groups include acryloyl, methacryloyl, acryloyloxy, and methacryloyloxy.

[0132] Examples of azo dyes represented by formula (1) include compounds represented by any of formulas (1-1) to (1-8). These azo dyes can be used alone or in combination of two or more.

[0133] [Chemical Formula 6]

[0134]

[0135] In equations (1-1) to (1-8),

[0136] B 1 ~B 30 Each of the following can be independently represented as 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 substituted and unsubstituted amino groups are as described above), a chlorine atom, or a trifluoromethyl group.

[0137] n1 to n4 represent integers from 0 to 3 independently.

[0138] When n1 is 2 or more, multiple B 2 They can be the same or different.

[0139] When n² is 2 or more, multiple B 6 They can be the same or different.

[0140] When n3 is 2 or more, multiple B 9 They can be the same or different.

[0141] When n4 is 2 or more, multiple B 14 They can be the same or different.

[0142] The polarizer constituting the polarizing film of the present invention comprises a structural unit having polymerizable groups derived from a liquid crystal compound or a dichroic pigment. When the polarizer comprises this structural unit, it bonds with the polymerizable groups of the structural unit (ii) of the polymer (I') constituting the photo-alignment film, thereby easily forming a polarizing film with excellent adhesion between the photo-alignment film and the polarizer. Therefore, the dichroic pigment in the present invention can also be a dichroic pigment having polymerizable groups.

[0143] When a dichroic pigment has a polymerizable group, examples of polymerizable groups include those present in the structural unit (ii) constituting the polymer (I'). From the viewpoint of ease of reaction control, (meth)acryloyl, (meth)acryloyloxy, vinyloxy, oxetyl, and oxetyl are preferred, more preferably (meth)acryloyl and (meth)acryloyloxy, and even more preferably (meth)acryloyloxy. The polymerizable group in the dichroic pigment can be a single type or a combination of two or more types, but is preferably the same polymerizable group as the polymerizable group present in the structural unit (ii). The number of polymerizable groups present in the dichroic pigment is not particularly limited; one or more is sufficient.

[0144] Examples of dichroic pigments having polymerizable groups include compounds with polymerizable groups represented by formula (1) above, and compounds represented by formula (2) below.

[0145] [Chemical Formula 7]

[0146]

[0147] In formula (2),

[0148] m represents an integer from 0 to 3;

[0149] A 1 A 2 and A 3 Each can be represented independently as a divalent aromatic group that may have substituents;

[0150] L 1 and L 2 These can be used independently to represent single bonds, -CH2-, -CH2CH2-, -O-, -CH2O-, -OCH2-, -CO-, -COO-, -OCO-, -OCOO-, and -CR. c =CR d -、-C≡C-、-CR c =N-、-CONR c -、-NR c CO-, or -N=N-, where R c and R d Each can be independently represented as an alkyl group having 1 to 4 hydrogen atoms or carbon atoms;

[0151] Z 1 Z represents a polymerizable group. 2 Represents a hydrogen atom or a polymeric group;

[0152] Q 1 and Q 2 Each of these terms independently represents a straight-chain or branched alkylene group having 1 to 20 carbon atoms that may have substituents, an alkenyl group having 1 to 20 carbon atoms that may have substituents, or an ynylene group having 1 to 20 carbon atoms that may have substituents, wherein the -CH2- group contained in these alkylene, alkenyl, or ynylene groups may be -O-, -S-, or NR-. e - Replace, here, R e Indicates an alkyl group having 1 to 4 hydrogen atoms or carbon atoms;

[0153] T 1 This indicates a single bond, -O-, -S-, -CO-, -COO-, -OCO-, -OCOO-, or -CONR. f - or -NR f CO-, T 2 This indicates a single bond, -O-, -S-, -CO-, -COO-, -OCO-, -OCOO-, -CONR f -、-NR f CO- or -NR g - Here, R f and R g R represents, independently, an alkyl group having 1 to 4 hydrogen atoms or carbon atoms. g The alkyl group indicated can be combined with Q. 1 Or Q 2Forming a ring, A 1 -(L 1 -A 2 ) m -L 2 -A 3 Contains at least one of -A X1 -N=NA X2 -(where A is in the formula) X1 and A X2 Each represents a divalent aromatic group) representing a structure, in T 2 For -NR g In the case of - Z 2 [Represents a hydrogen atom]

[0154] The content of the dichroic pigment can be appropriately determined depending on the type of dichroic pigment used. From the viewpoint of easily improving the adhesion to the photo-alignment film and the dichroic ratio, it is acceptable to have, for example, 1 to 99 parts by mass relative to 100 parts by mass of the solid component of the polarizing film forming composition, preferably 2 parts by mass or more, more preferably 3 parts by mass or more. In addition, from the viewpoint of easily increasing the orientation order of the polarizer, it is preferable to have 80 parts by mass or less, more preferably 50 parts by mass or less, further preferably 25 parts by mass or less, and particularly preferably 10 parts by mass or less. When multiple dichroic pigments are included as dichroic pigments, it is preferable that the total amount of all dichroic pigments contained in the polarizer forming composition is within the above-mentioned range.

[0155] It should be noted that the dichroism ratio refers to the ratio of the absorption intensities of two linearly polarized rays of light incident on a polarizer that vibrate perpendicularly to each other. It is defined as the ratio (AV / AH) of absorbance along the extinction axis (measured with perpendicular incidence) to absorbance along the transmission axis. The transmission axis (polarization axis) points towards the polarized component of the incident light that passes through the polarizer, while the extinction axis (absorption axis) points towards the polarized component of the incident light that is absorbed by the polarizer.

[0156] The structural units with polymerizable groups in the polarizer can also be structural units derived from liquid crystal compounds with polymerizable groups. In one aspect of the present invention, from the viewpoint of easily improving adhesion to the photo-alignment film and easily improving alignment, the polarizer forming composition preferably includes a polymerizable liquid crystal compound. Here, a liquid crystal compound refers to a liquid crystal material exhibiting liquid crystal properties. The previously described dichroic pigments with polymerizable groups can also be one type of liquid crystal material with polymerizable groups, but the polymerizable liquid crystal compounds referred to here do not include dichroic pigments with polymerizable groups. Hereinafter, polymerizable liquid crystal compounds other than dichroic pigments with polymerizable groups will be referred to as "polymerizable liquid crystal compound (A)". In the present invention, the polarizer forming composition preferably includes a liquid crystal material with polymerizable groups, and in one aspect of the present invention, polymerizable liquid crystal compound (A) is included as the liquid crystal material with polymerizable groups.

[0157] Examples of polymerizable groups in the polymeric liquid crystal compound (A) include those found in structural units (ii) of the polymer (I') forming the photo-alignment film. From the viewpoint of easy reaction control, preferred polymerizable groups are (meth)acryloyl, (meth)acryloyloxy, vinyloxy, oxetyl, and oxetyl, more preferably (meth)acryloyl and (meth)acryloyloxy, and even more preferably (meth)acryloyloxy. The polymerizable group in the polymeric liquid crystal compound (A) can be one type or a combination of two or more types. Because it is possible to form bonds with the polymerizable groups in structural units (ii) constituting the polymer (I'), thereby easily forming a polarizing film with excellent adhesion between the photo-alignment film and the polarizer, the polymerizable group in the polymeric liquid crystal compound (A) is preferably the same as the polymerizable group in structural unit (ii).

[0158] The polymerizable liquid crystal compound (A) can be a thermotropic liquid crystal or a lyotropic liquid crystal, but is preferably a thermotropic liquid crystal. Furthermore, the polymerizable liquid crystal compound (A) can be a thermotropic liquid crystal compound displaying a nematic liquid crystal phase or a thermotropic liquid crystal compound displaying a smectic liquid crystal phase. In this invention, from the viewpoint of obtaining higher polarization characteristics, the polymerizable liquid crystal compound (A) is preferably a thermotropic liquid crystal compound displaying a smectic liquid crystal phase, more preferably a thermotropic liquid crystal compound displaying a higher-order smectic liquid crystal phase. More preferably, it is a thermotropic liquid crystal compound displaying a 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, or smectic L phase, and even more preferably a thermotropic liquid crystal compound displaying a smectic B phase, smectic F phase, or smectic I phase. If the liquid crystal phase formed by the polymerizable liquid crystal compound (A) is one of these higher-order smectic phases, it is easier to obtain a polarizer with higher polarization performance. Furthermore, such polarizers with high polarization performance can produce Bragg peaks from higher-order structures such as hexagonal and crystalline phases in X-ray diffraction measurements. The polarizers of the present invention comprise polymers of such polymeric liquid crystal compounds, preferably polymers of polymeric liquid crystal compounds polymerized in a smectic state, which is preferred from the viewpoint of obtaining higher polarization characteristics.

[0159] As for the polymerizable liquid crystal compound (A), there is no particular limitation as long as it is a liquid crystal compound having at least one polymerizable group, and known polymerizable liquid crystal compounds can be used, but compounds exhibiting smectic liquid crystal properties are preferred. For example, compounds represented by the following formula (A1) (hereinafter sometimes referred to as "polymerizable liquid crystal compound (A1)") can be cited as such polymerizable liquid crystal compounds.

[0160] U 1A -V 1A -W 1A -(X 1A -Y 1A -) n -X 2A -W A2 -V 2A -U 2A (A1)

[0161] In formula (A1),

[0162] X 1A and X 2AEach of these groups independently represents a divalent aromatic group or a divalent alicyclic hydrocarbon group. Here, the hydrogen atom in the divalent aromatic group or divalent alicyclic hydrocarbon group can be replaced by a halogen atom, an alkyl group with 1 to 4 carbon atoms, a fluoroalkyl group with 1 to 4 carbon atoms, an alkoxy group with 1 to 4 carbon atoms, a cyano group, or a nitro group. The carbon atoms constituting the divalent aromatic group or divalent alicyclic hydrocarbon group can be replaced by oxygen atoms, sulfur atoms, or nitrogen atoms. Wherein, X 1A and X 2A At least one of them is 1,4-phenylene or cyclohexane-1,4-diyl, which may have substituents.

[0163] Y 1A It is a single bond or a divalent linker.

[0164] When n is 1 to 3, and n is 2 or more, there are multiple X's. 1A They can be the same or different. X 2A Can be used with multiple X 1A Any one or all of them can be the same, or they can be different. Furthermore, when n is 2 or more, multiple Ys... 1A They can be the same or different. From the viewpoint of liquid crystal properties, n is preferably 2 or more.

[0165] U 1A It represents a hydrogen atom or a polymeric group.

[0166] U 2A It indicates a polymerizable group.

[0167] W 1A and W 2A Each group is a single bond or a divalent linker, independent of the others.

[0168] V 1A and V 2A Each of these groups independently represents an alkane diene with 1 to 20 carbon atoms that may have substituents, wherein the -CH2- group constituting the alkane diene can be replaced by -O-, -CO-, -S-, or NH-.

[0169] In polymeric liquid crystal compounds (A1), X 1A and X 2A Independently preferred are 1,4-phenylene, which may have substituents, or cyclohexane-1,4-diyl, which may have substituents, X 1A and X 2AAt least one of the components is a 1,4-phenylene group that may have a substituent, or a cyclohexane-1,4-diyl group that may have a substituent, preferably trans-cyclohexane-1,4-diyl. Examples of substituents optionally present in the 1,4-phenylene group that may have a substituent, or the cyclohexane-1,4-diyl group that may have a substituent, include alkyl groups having 1 to 4 carbon atoms such as methyl, ethyl, and butyl, cyano groups, and halogen atoms such as chlorine and fluorine atoms. Unsubstituted components are preferred.

[0170] Furthermore, for polymerizable liquid crystal compounds (A1), from the viewpoint of easily exhibiting smectic liquid crystal properties, it is preferable that the part represented by formula (A1-1) in formula (A1) [hereinafter also referred to as partial structure (A1-1)] is an asymmetric structure.

[0171] -(X 1A -Y 1A -) n -X 2A - (A1-1)

[0172] [In the formula, X] 1A Y 1A X 2A And n each have the same meaning as above.

[0173] As a polymeric liquid crystal compound (A1) with a partially asymmetric structure (A1-1), examples include those with n=1 and 1 X. 1A With X 2A These are polymeric liquid crystal compounds (Al) with different structures from each other. Additionally, examples can be given of compounds with n = 2 and 2 Y atoms. 1A Two X's are compounds with the same structure. 1A For the same structure and 1 X 2A To be with these two X 1A Polymerizable liquid crystal compounds with different structures (A1), 2 X 1A The bond in W 1A X 1A For another X 1A and X 2A Different structures and another X 1A With X 2A These are polymeric liquid crystal compounds (Al) with identical structures. Furthermore, examples can be given of compounds with n = 3 and 3 Y atoms. 1A Three X's of compounds with the same structure 1A and 1 X 2A Any one of them is a polymeric liquid crystal compound (A1) with a structure completely different from the other three.

[0174] Y 1APreferred bonds include -CH2CH2-, -CH2O-, -CH2CH2O-, -COO-, -OCOO-, single bonds, -N=N-, and -CR. a =CR b -、-C≡C-、-CR a =N- or -CO-NR a -. R a and R b Each can be independently represented as either a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. 1A More preferably, it is -CH2CH2-, -COO-, or a single bond, and multiple Y bonds exist. 1A In the case of X 2A Bonded Y 1A More preferably, it is -CH2CH2- or -CH2O-. X 1A and X 2A When all structures are identical, it is preferable to have two or more Y atoms with different bonding methods. 1A There exist multiple Ys with different bonding methods. 1A In this case, it becomes an asymmetric structure, and therefore tends to exhibit smectic liquid crystal properties.

[0175] U 2A It is a polymerizable group. U 1A It is a hydrogen atom or a polymeric group, preferably a polymeric group. U is preferred. 1A and U 2A All are polymerizable groups, preferably free radical polymerizable groups. Examples of polymerizable groups include those previously exemplified as polymerizable groups present in the polymerizable liquid crystal compound (A). When the polymerizable group is the same as the polymerizable group in the structural unit (ii) constituting the polymer (I') forming the photo-alignment film, there is a tendency for improved adhesion between the photo-alignment film and the polarizer, which is therefore preferred. 1A The polymerizable group represented by U 2A The polymerizable groups represented may differ from one another, but are preferably of the same kind. Furthermore, U is preferred. 1A and U 2A At least one of them is (meth)acryloyl, more preferably both are (meth)acryloyl. In addition, the polymerizable group can be in a polymerized state or in an unpolymerized state, but is preferably in an unpolymerized state.

[0176] As V 1A and V 2AExamples of alkane diyl groups include methylene, ethylene, propane-1,3-diyl, butane-1,3-diyl, butane-1,4-diyl, pentane-1,5-diyl, hexane-1,6-diyl, heptane-1,7-diyl, octane-1,8-diyl, decane-1,10-diyl, tetradecane-1,14-diyl, and eicosane-1,20-diyl. 1A and V 2A Preferably, it is an alkane diester with 2 to 12 carbon atoms, and more preferably an alkane diester with 6 to 12 carbon atoms.

[0177] Examples of substituents that may be optionally present in the alkane diene include cyano groups and halogen atoms. The alkane diene is preferably unsubstituted, and more preferably an unsubstituted straight-chain alkane diene.

[0178] W 1A and W 2A The components are preferably single bonds, -O-, -S-, -COO-, or -OCOO-, and more preferably single bonds or -O-.

[0179] As for the polymeric liquid crystal compound (A), there are no particular limitations as long as it is a polymeric liquid crystal compound having at least one polymeric group and exhibiting liquid crystal properties; any known polymeric liquid crystal compound can be used. As the polymeric liquid crystal compound (A), a polymeric liquid crystal compound exhibiting smectic liquid crystal properties is preferred, and a compound exhibiting higher-order smectic liquid crystal properties is more preferred. As a structure that readily exhibits smectic liquid crystal properties, a molecular structure having asymmetry in its molecular structure is preferred; specifically, a polymeric liquid crystal compound exhibiting smectic liquid crystal properties and having a structure represented by formulas (Aa) to (Ai) is more preferred. From the viewpoint of readily exhibiting higher-order smectic liquid crystal properties, a structure represented by any one of formulas (Aa), (Ab), and (Ac) is further preferred, and a structure represented by formula (Aa) or (Ac) is particularly preferred. It should be noted that in the following formulas, * denotes a connecting bond.

[0180] [Chemical Formula 8]

[0181]

[0182] Specifically, examples of polymerizable liquid crystal compounds (A) include compounds represented by formulas (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 the trans form.

[0183] [Chemical Formula 9]

[0184]

[0185] [Chemical Formula 10]

[0186]

[0187] [Chemical Formula 11]

[0188]

[0189] [Chemical Formula 12]

[0190]

[0191] [Chemical Formula 13]

[0192]

[0193] Preferably, at least one compound is selected from the group consisting of compounds represented by formulas (A-2), (A-3), (A-4), (A-5), (A-6), (A-7), (A-8), (A-13), (A-14), (A-15), (A-16), and (A-17). As the polymerizable liquid crystal compound (A), one compound may be used alone, or two or more compounds may be used in combination.

[0194] The polymerizable liquid crystal compound (A) can be manufactured using known methods, such as those described in Lub et al., Recl. Trav. Chim. Pays-Bas, 115, 321-328 (1996), or Japanese Patent No. 4719156.

[0195] In this invention, when the polarizer forming composition contains a polymeric liquid crystal compound (A), its content is, for example, 1 to 99 parts by mass relative to 100 parts by mass of the solid component of the polarizer forming composition, preferably 40 parts by mass or more, more preferably 50 parts by mass or more, further preferably 60 parts by mass or more, particularly preferably 70 parts by mass or more, especially preferably 80 parts by mass or more, and preferably 98 parts by mass or less, more preferably 95 parts by mass or less.

[0196] When the composition for forming a polarizer contains two or more polymeric liquid crystal compounds (A), at least one of them may be a polymeric liquid crystal compound (A1), or all of them may be polymeric liquid crystal compounds (A1). By combining multiple polymeric liquid crystal compounds, liquid crystal properties can sometimes be temporarily maintained even at temperatures below the liquid crystal-crystallization phase transition temperature.

[0197] The composition for forming a polarizer may further include a polymerization initiator. A polymerization initiator is a compound capable of initiating a polymerization reaction of a crystalline substance having polymerizable groups that may be included in the composition for forming a polarizer. There are no particular limitations on the polymerization initiator, as long as it is a compound capable of initiating a polymerization reaction of a crystalline substance having polymerizable groups; known polymerization initiators can be used, with photopolymerization initiators being preferred. Specifically, examples include photopolymerization initiators that generate active free radicals through light irradiation, or photopolymerization initiators that generate acids. Photopolymerization initiators can be used alone or in combination of two or more.

[0198] Examples of photopolymerization initiators that generate active free radicals include self-destructive photopolymerization initiators such as benzoin compounds, acetophenone compounds, hydroxyacetophenone compounds, α-aminoacetophenone compounds, oxime ester compounds, acylphosphine oxide compounds, and azo compounds; and hydrogen-abstracting photopolymerization initiators such as benzophenone compounds, alkylacetophenone compounds, benzoyl ether compounds, benzoin ketal compounds, dibenzocycloheptanone compounds, anthraquinone compounds, xanthonone compounds, thioxanthonone compounds, halogenated acetophenone compounds, dialkoxyacetophenone compounds, halogenated diimidazole compounds, halogenated triazine compounds, and triazine compounds.

[0199] Examples of photopolymerization initiators that produce acids include iodonium salts and matte salts.

[0200] Among these photopolymerization initiators, photopolymerization initiators that generate active free radicals through light irradiation are preferred. From the viewpoint of excellent reaction efficiency at low temperatures, self-destructive photopolymerization initiators are preferred, and acetophenone compounds, hydroxyacetophenone compounds, α-aminoacetophenone compounds, and oxime ester compounds are particularly preferred.

[0201] Examples of benzoin compounds include, for example, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, and benzoin isobutyl ether.

[0202] Examples of acetophenone compounds include, for example, diethoxyacetophenone, 2-methyl-2-morpholino-1-(4-methylthiophenyl)propane-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butane-1-one, 2-hydroxy-2-methyl-1-phenylpropane-1-one, 1,2-diphenyl-2,2-dimethoxyethane-1-one, 2-hydroxy-2-methyl-1-[4-(2-hydroxyethoxy)phenyl]propane-1-one, 1-hydroxycyclohexylphenyl ketone, and oligomers of 2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propane-1-one.

[0203] Examples of oxime ester compounds include, for example, Irgacure (registered trademark) OXE-01, Irgacure (registered trademark) OXE-02, Irgacure (registered trademark) OXE-03 (all manufactured by BASF Japan Ltd.), ADEKA OPTOMER (registered trademark) N-1919, and ADEKA ARKLS (registered trademark) NCI-831 (all manufactured by ADEKA Co., Ltd.).

[0204] Examples of acylphosphine oxide compounds include 2,4,6-trimethylbenzoyl diphenylphosphine oxide and bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide.

[0205] Examples of benzophenone compounds include, for example, benzophenone, methyl o-benzoylbenzoate, 4-phenylbenzophenone, 4-benzoyl-4'-methyldiphenyl sulfide, 3,3',4,4'-tetra(tert-butylperoxycarbonyl)benzophenone, 2,4,6-trimethylbenzophenone, etc.

[0206] Examples of alkyl phenyl ketone compounds include, for example, diethoxyacetophenone, 2-methyl-2-morpholino-1-(4-methylthiophenyl)propane-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butane-1-one, 2-hydroxy-2-methyl-1-phenylpropane-1-one, 1,2-diphenyl-2,2-dimethoxyethane-1-one, 2-hydroxy-2-methyl-1-[4-(2-hydroxyethoxy)phenyl]propane-1-one, 1-hydroxycyclohexylphenyl ketone, and oligomers of 2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propane-1-one.

[0207] Examples of triazine compounds include, for instance, 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, and 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, 2,4-bis(trichloromethyl)-6-[2-(4-diethylamino-2-methylphenyl)vinyl]-1,3,5-triazine, 2,4-bis(trichloromethyl)-6-[2-(3,4-dimethoxyphenyl)vinyl]-1,3,5-triazine, etc.

[0208] As polymerization initiators, Irgacure 907, Irgacure 184, Irgacure 651, Irgacure 819, Irgacure 250, Irgacure 369 (all manufactured by Ciba Japan Co., Ltd.), SEIKUOL BZ, SEIKUOL Z, SEIKUOL BEE (all manufactured by Seiko Chemical Co., Ltd.), Kayacure BP100 (manufactured by Nippon Kayaku Co., Ltd.), Kayacure UVI-6992 (manufactured by DOW Corporation), ADEKA OPTOMER SP-152 or ADEKA OPTOMER SP-170 (all manufactured by ADEKA Co., Ltd.), TAZ-A, and TAZ-PP (all manufactured by Nihon Siber Hegner) can also be used. Commercially available photopolymerization initiators include KK (manufactured by KK), TAZ-104 (manufactured by Sanwa Chemical Co., Ltd.), Esacure One, and EsacureKIP 150 (all manufactured by IGM Resins).

[0209] When the polarizer-forming composition contains a polymerization initiator, the content of the polymerization initiator can be appropriately adjusted according to the type and amount of the liquid crystal substance with polymerizable groups contained in the polarizer-forming composition participating in the polymerization reaction. Preferably, the content of the polymerization initiator is 0.1 to 30 parts by mass relative to 100 parts by mass of the solid component of the polarizer-forming composition, more preferably 0.5 to 15 parts by mass, and even more preferably 1 to 10 parts by mass.

[0210] The composition for forming polarizers may contain additives as needed, as long as they do not impair the effects of the present invention. Examples of additives include sensitizers, polymerization inhibitors, and leveling agents.

[0211] The composition for forming a polarizer may contain a sensitizer. A photosensitizer is preferred as the sensitizer. Examples of such sensitizers include, for instance, xanthone compounds such as xanthone or thioxanthone (e.g., 2,4-diethylthioxanthone, 2-isopropylthioxanthone), anthracene or anthracene compounds having substituents such as alkyl ethers (e.g., dibutoxyanthracene), phenothiazine, or rubrene.

[0212] When the polarizer-forming composition contains a sensitizer, it promotes the polymerization reaction of the liquid crystal material containing polymerizable groups in the composition, and the film strength of the obtained polarizer is easily improved. When the polarizer-forming composition contains a photosensitizer, from the viewpoint of easily promoting the polymerization reaction without impairing the orientation of the obtained polarizer, the content of the sensitizer is preferably 0.1 to 30 parts by mass, more preferably 0.3 to 10 parts by mass, and even more preferably 0.5 to 8.0 parts by mass, relative to 100 parts by mass of the solid components of the polarizer-forming composition.

[0213] Examples of polymerization inhibitors include hydroquinone or hydroquinones with alkyl ethers or other substituents, catechols with alkyl ethers or other substituents such as butylcatechol, pyrogallols, free radical scavengers such as 2,2,6,6-tetramethylpiperidine-1-oxy radical, thiophenols, β-naphthylamines, or β-naphthols.

[0214] When the polarizer-forming composition contains a polymerization inhibitor, polymerization can be carried out while suppressing the occurrence of orientation disorder of the liquid crystal material having polymerizable groups. From the viewpoint of suppressing orientation disorder of the liquid crystal material having polymerizable groups, the content of the polymerization inhibitor is preferably 0.1 to 30 parts by mass, more preferably 0.3 to 10 parts by mass, and even more preferably 0.5 to 8.0 parts by mass, relative to 100 parts by mass of the solid component of the polarizer-forming composition.

[0215] The composition for forming polarizers may contain a leveling agent. A leveling agent is an additive that has the function of adjusting the flowability of the composition and making the film obtained by coating the composition flatter. Examples of leveling agents include organic modified silicone oils, polyacrylates, and perfluoroalkyls.Specifically, examples include DC3PA, SH7PA, DC11PA, SH28PA, SH29PA, SH30PA, ST80PA, ST86PA, SH8400, SH8700, FZ2123 (all manufactured by Dow Corning Toray Co., Ltd.), KP321, KP323, KP324, KP326, KP340, KP341, X22-161A, KF6001 (all manufactured by Shin-Etsu Chemical Co., Ltd.), TSF400, TSF401, TSF410, TSF4300, TSF4440, TSF4445, TSF-4446, TSF4452, TSF4460 (all manufactured by Momentive Advanced Materials Japan Contract Co., Ltd.), fluorinert (registered trademark) FC-72, and fluorinert. FC-40, fluorinert FC-43, fluorinert FC-3283 (all manufactured by Sumitomo 3MLtd.), 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-477, MEGAFACE F-479, MEGAFACE F-482, MEGAFACE F-483 (all manufactured by DIC Co., Ltd.), Eftop (trade name) EF301, Eftop EF303, Eftop EF351, Eftop EF352 (all manufactured by Mitsubishi Materials Electronic Chemicals). (Manufactured by Co., Ltd.), Surflon (registered trademark) S-381, Surflon S-382, Surflon S-383, Surflon S-393, Surflon SC-101, Surflon SC-105, KH-40, SA-100 (all manufactured by AGCSeimi Chemical Co., Ltd.), trade name E1830, trade name E5844 (manufactured by Daikin Fine Chemical Kenkyusho, KK), BM-1000, BM-1100, BYK-352, BYK-353 and BYK-361N (all trade name: manufactured by BMChemie), etc. Among them, polyacrylate leveling agents and perfluoroalkyl leveling agents are preferred.

[0216] When the polarizer forming composition includes a leveling agent, from the viewpoint of improving orientation and easily making the resulting polarizer smooth, the amount of leveling agent is preferably 0.01 to 30 parts by weight, more preferably 0.03 to 10 parts by weight, and even more preferably 0.05 to 8.0 parts by weight, relative to 100 parts by weight of the solid component of the polarizer forming composition. The leveling agent can be used alone or in combination of two or more types.

[0217] In addition to sensitizers, polymerization inhibitors, and leveling agents, additives that may be included in the polarizer-forming composition include, for example, antioxidants, release agents, stabilizers, colorants such as bluing agents, flame retardants, and lubricants. When the polarizer-forming composition contains these additives, the total mass content of the additives relative to the solid components of the polarizer-forming composition is preferably greater than 0% and less than 20% by mass, more preferably greater than 0% and less than 10% by mass.

[0218] The polarizer-forming composition can be manufactured using conventionally known preparation methods. It is typically prepared by mixing and stirring a dichroic pigment, a polymerizable liquid crystal compound (A) as needed, a polymerization initiator, and the aforementioned additives. Furthermore, compounds exhibiting smectic liquid crystal properties generally have high viscosity. Therefore, from the viewpoint of improving the coatability of the polarizer-forming composition to facilitate polarizer formation, the viscosity can be adjusted by adding a solvent to the polarizer-forming composition.

[0219] As a solvent, an organic solvent that can dissolve the components contained in the composition for forming the polarizer and is inactive for the polymerization reaction is preferred. Specifically, examples include alcohol solvents such as methanol, ethanol, ethylene glycol, isopropanol, propylene glycol, methyl cellosolve, butyl cellosolve, or propylene glycol monomethyl ether; ester solvents such as ethyl acetate, butyl acetate, ethylene glycol methyl ether acetate, γ-butyrolactone, propylene glycol methyl ether acetate, or ethyl lactate; ketone solvents such as acetone, methyl ethyl ketone, cyclopentanone, cyclohexanone, methyl pentyl ketone, or methyl isobutyl ketone; non-chlorinated aliphatic hydrocarbon solvents such as pentane, hexane, or heptane; non-chlorinated aromatic solvents such as toluene, xylene, or phenol, and nitrile solvents such as acetonitrile; ether solvents such as tetrahydrofuran or dimethoxyethane; chlorinated aliphatic hydrocarbon solvents such as chloroform or chlorobenzene; and amide solvents such as dimethylacetamide, dimethylformamide, N-methyl-2-pyrrolidone, and 1,3-dimethyl-2-imidazolinone. These organic solvents can be used alone or in combination of two or more.

[0220] When the polarizer forming composition contains a solvent, the concentration of the solid component in the polarizer forming composition is preferably 2% by mass or more, more preferably 5% by mass or more, even more preferably 10% by mass or more, and preferably 50% by mass or less, more preferably 40% by mass or less, and even more preferably 30% by mass or less. If the solid component concentration is above or below the above-mentioned lower limit, the resulting polarizer will not be excessively thin, and the dichroism required for the polarizer can be easily obtained. In addition, if the solid component concentration is below or below the above-mentioned upper limit, the viscosity of the polarizer forming composition becomes lower, and there is a tendency for uneven coating thickness to occur.

[0221] The viscosity of the composition for forming polarizers is preferably 0.1 to 10 mPa·s, more preferably 0.1 to 7 mPa·s, and even more preferably 0.1 to 5 mPa·s. If the viscosity of the composition for forming polarizers is within the above range, the composition has excellent operability and coatability, and it is easy to obtain a polarizer with uniform thickness.

[0222] In this invention, the polarizer is a cured product of a liquid crystal composition (a composition for forming a polarizer), which can be obtained by polymerizing the liquid crystal material contained in the composition. It should be noted that a polarizer is a material that decomposes unpolarized incident light into two orthogonal polarized light components, allowing one polarized light component to pass through while absorbing the other. The axis of the transmitted polarized light component is called the transmission axis, and the axis of the absorbed polarized light component is called the absorption axis.

[0223] In this invention, the polarizer is adjacent to the photoalignment film, exhibiting a high degree of adhesion with the photoalignment film. One reason for this effect can be considered as follows: during the formation of the polarizer, which is a cured product of the liquid crystal composition, the polymeric groups contained in the polymer (I') constituting the photoalignment film react simultaneously with the polymerization reaction of the liquid crystal compound or dichroic pigment having polymeric groups used to form the polarizer, and bond with the polymeric groups of the liquid crystal compound or dichroic pigment forming the polarizer, thereby creating a denser bond between the polarizer and the photoalignment film.

[0224] Furthermore, the photo-alignment film formed from polymer (I') exhibits excellent solvent resistance, thus displaying high liquid crystal alignment capability and easily forming polarizers with high alignment order. Polarizers with high alignment order can produce Bragg peaks from higher-order structures such as hexagonal and crystalline phases in X-ray diffraction measurements. A Bragg peak refers to a peak originating from the planar periodic structure of molecular alignment; the polarizer constituting the polarizer of the present invention preferably displays Bragg peaks in X-ray diffraction measurements. That is, in the polarizer constituting the polarizer of the present invention, the polymeric liquid crystal compound or its polymer is preferably aligned in such a way that the polarizer displays Bragg peaks in X-ray diffraction measurements, more preferably with "horizontal alignment" (i.e., the molecules of the polymeric liquid crystal compound are aligned along the direction of light absorption). In the present invention, the planar periodic interval of molecular alignment is... The preferred polarizer is the one that exhibits the Bragg peak. A high degree of orientational order can be achieved by controlling the type of polymerizable liquid crystal compound used, the type and amount of the dichroic pigment, and the type and amount of the polymerization initiator.

[0225] The thickness of the polarizer can be suitably determined according to the application of the optical laminate in which the polarizer is assembled, and is preferably 0.1 μm to 10 μm, more preferably 0.3 μm to 5 μm, and even more preferably 0.5 μm to 3 μm. If the thickness of the polarizer is above the lower limit mentioned above, the liquid crystal material is less likely to align in the vertical direction, thus the alignment order is easily improved. Conversely, if the thickness of the polarizer is below the upper limit mentioned above, the liquid crystal material is less likely to align randomly, thus the alignment order is easily improved. The thickness of the polarizer can be measured using an interferometer, a laser microscope, or a stylus-type thickness gauge.

[0226] Polarizing films can be obtained, for example, by a method comprising the steps of: coating a polarizing film forming composition onto a photo-alignment film; and curing the coated polarizing film forming composition.

[0227] In one aspect of the present invention, if the polarizer forming composition contains a solvent, the solvent contained in the composition can be removed after coating the polarizer forming composition, and the polarizer forming composition with the solvent removed can be cured to form a polarizer.

[0228] Furthermore, when the polarizer forming composition contains a polymeric liquid crystal compound as a liquid crystal material, it can be obtained, for example, by a method including the following steps: heating the polymeric liquid crystal compound to a temperature above which the polymeric liquid crystal compound phase transforms into a liquid phase and then cooling it to transform the polymeric liquid crystal compound phase into a liquid crystal phase (smectic phase); and polymerizing the polymeric liquid crystal compound while maintaining the aforementioned liquid crystal phase.

[0229] Methods for coating a polarizer-forming composition onto a photo-alignment film include known methods such as spin coating, extrusion, gravure coating, die coating, bar coating, applicator coating, and printing methods such as flexographic printing.

[0230] When removing the solvent, it is preferable to remove the solvent by drying or the like, under conditions where the polymerizable liquid crystal compound contained in the coating film of the polarizer forming composition does not polymerize, thereby forming a dry coating film. Examples of drying methods include natural drying, ventilation drying, heating drying, and reduced pressure drying.

[0231] The drying temperature can be, for example, 50–200°C, preferably 100°C or higher, more preferably 110°C or higher, even more preferably 120°C or higher, and preferably 150°C or lower. If the drying temperature is within the above range, the solvent in the coating can be removed efficiently. Furthermore, the effect of temperature on the photoalignment film on which the coating is formed can be suppressed, and the reduction in the liquid crystal alignment capability exhibited by the photoalignment film is less likely to occur. The drying time is preferably 20 seconds to 10 minutes, more preferably 30 seconds to 5 minutes.

[0232] In cases where the liquid crystal material is transformed into a liquid phase, the phase transformation can be carried out after the solvent in the aforementioned coating is removed, or it can be carried out simultaneously with the removal of the solvent.

[0233] A polarizer is formed by polymerizing a liquid crystal substance while maintaining its liquid crystal state, thereby forming a cured product of a polarizer-forming composition. The polymerization method can be suitably selected from photopolymerization, thermal polymerization, etc., depending on the type of polymerizable groups. Photopolymerization allows for polymerization at low temperatures and is easy to manufacture industrially; therefore, in one aspect of the present invention, photopolymerization is preferred as the polymerization method. In photopolymerization, the light irradiating the dried coating film can be suitably selected based on the type of polymerizable liquid crystal compound, etc., contained in the dried coating film (especially the type of polymerizable groups possessed by the polymerizable liquid crystal compound, etc.), the type of polymerization initiator, and their amounts. Specific examples include one or more active energy rays or active electron rays selected from the group consisting of visible light, ultraviolet light, infrared light, X-rays, alpha rays, beta rays, and gamma rays. From the perspective of easy control of the polymerization reaction and the availability of devices widely used in this field as photopolymerization apparatus, ultraviolet light is preferred. It is also preferable to select the type of polymerizable liquid crystal compound and polymerization initiator contained in the polarizer-forming composition in advance in a manner that allows photopolymerization using ultraviolet light. Furthermore, during polymerization, light irradiation can be performed simultaneously with cooling the dried coating using appropriate cooling methods, thereby controlling the polymerization temperature. During photopolymerization, patterned polarizers can also be obtained through masking, development, etc.

[0234] Examples of light sources for the aforementioned active energy rays include low-pressure mercury lamps, medium-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, xenon lamps, halogen lamps, carbon arc lamps, tungsten lamps, gallium lamps, excimer lasers, LED light sources emitting light in the wavelength range of 380–440 nm, chemical lamps, black light lamps, microwave-excited mercury lamps, and metal halide lamps.

[0235] Ultraviolet radiation intensity is typically 10–3,000 mW / cm². 2 The intensity of ultraviolet irradiation is preferably within the wavelength range effective for activating the polymerization initiator. The irradiation time is typically 0.1 seconds to 10 minutes, preferably 1 second to 5 minutes, more preferably 5 seconds to 3 minutes, and even more preferably 10 seconds to 1 minute. When irradiated once or multiple times at such an intensity, the cumulative light intensity is 10 to 3,000 mJ / cm². 2 Preferably, it is 50–2,000 mJ / cm². 2 More preferably 100–1,000 mJ / cm 2 .

[0236] When the composition for forming a polarizer includes a polymerizable liquid crystal compound (A), photopolymerization is performed, thereby polymerizing the polymerizable liquid crystal compound (A) while maintaining a liquid crystal phase, especially a smectic phase, preferably a higher-order smectic phase, to form a polarizer. For polarizers obtained by polymerizing while maintaining the smectic liquid crystal phase of the polymerizable liquid crystal compound, the aforementioned dichroic pigment also plays a role, resulting in higher polarization performance compared to conventional host-guest type polarizing films, i.e., polarizers formed from a nematic liquid crystal phase. Furthermore, it also has the advantage of superior strength compared to cases where only a dichroic pigment or lyotropic liquid crystal is coated.

[0237] [Polarizing plate]

[0238] The present invention also includes a polarizing plate comprising the polarizing film of the present invention and a substrate disposed on the light alignment film side of the polarizing film.

[0239] Examples of substrates include glass substrates and membrane substrates, with membrane substrates being preferred. Examples of resins constituting the membrane substrate include: polyolefins such as polyethylene, polypropylene, and norbornene polymers; cyclic olefin resins; polyvinyl alcohol; polyethylene terephthalate; polymethacrylate; polyacrylate; cellulose esters such as cellulose triacetate, cellulose diacetate, and cellulose acetate propionate; polyethylene naphthalate; polycarbonate; polysulfone; polyethersulfone; polyetherketone; polyphenylene sulfide and polyphenylene ether; and other resins.

[0240] Examples of commercially available cellulose ester substrates include "Fujitac Film" (manufactured by Fuji Photo Film Co., Ltd.); "KC8UX2M", "KC8UY" and "KC4UY" (manufactured by Konica Minolta Opto Co., Ltd.).

[0241] Examples of commercially available cyclic olefin resins include "Topas" (registered trademark) (manufactured by Ticona GmbH (Germany), "ARTON" (registered trademark) (manufactured by JSR Corporation), "ZEONOR" (registered trademark), "ZEONEX" (registered trademark) (manufactured by Zeon Corporation, Japan), and "APEL" (registered trademark) (manufactured by Mitsui Chemicals Co., Ltd.). These cyclic olefin resins can be used to form films using known methods such as solvent casting and melt extrusion, thereby creating substrates. Commercially available cyclic olefin resin substrates can also be used. Examples of commercially available cyclic olefin resin substrates include "Esushina" (registered trademark), "SCA40" (registered trademark) (manufactured by Sekisui Chemicals Co., Ltd.), "ZEONOR FILM" (registered trademark) (manufactured by Optes Co., Ltd.), and "ARTON FILM" (registered trademark) (manufactured by JSR Corporation).

[0242] The required properties of the substrate vary depending on the composition of the polarizing plate, but a substrate with the smallest possible phase difference is generally preferred. Examples of substrates with the smallest possible phase difference include cellulose ester films such as Zero tack (Konica Minolta Opto Co., Ltd.) and Z tack (FUJI FILM Co., Ltd.), which do not have phase difference. Unstretched cyclic olefin resin substrates are also preferred. For the surface of the substrate without the polarizing film, hard coating, anti-reflective treatment, and antistatic treatment can be applied.

[0243] From a practical operability point of view, a thinner substrate is preferable, but from a strength and processability point of view, a thicker substrate is preferable. In one embodiment of the present invention, the substrate thickness is preferably 5 μm to 300 μm, more preferably 20 μm to 200 μm. Furthermore, the polarizing film can be peeled off from the substrate and transferred, thereby applying the polarizing film of the present invention only to optical laminates such as elliptical polarizing plates, thus achieving a further thinning effect for optical laminates used in image display panels, etc.

[0244] [Optical laminate]

[0245] This invention also includes an optical laminate comprising the polarizing plate of this invention and a layer bonded to the polarizer side of the aforementioned polarizing plate via an adhesive layer. Various optical layers, protective layers, etc., can be cited as the layer bonded to the polarizer of this invention in the optical laminate. These various optical layers are layers that function for image display (display screen, etc.) (e.g., layers that function to improve the ease of viewing images), and examples include films with various optical properties that can be fitted into image display devices. The optical layer can be, for example, a single-layer structure (e.g., a phase retardation film, brightness enhancement film, anti-glare film, anti-reflection film, diffusion film, light-concentrating film, etc., optically functional films), or a multi-layer structure (e.g., a phase retardation plate, etc.).

[0246] In the optical laminate of the present invention, the adhesive layer for bonding the polarizer to the layer adhered to the polarizer is a layer formed by an adhesive. The adhesive forming the adhesive layer may be a conventionally known adhesive, depending on the type of layer adhered to the polarizer, the layer composition of the optical laminate, etc.

[0247] The thickness of the adhesive layer can be appropriately determined according to the layer composition of the optical laminate, for example, it can be 0.1 to 30 μm.

[0248] This invention also includes an elliptical polarizer, which comprises the polarizing film of this invention and a phase retardation layer (hereinafter also referred to as "λ / 4 phase retardation layer") having the function of a 1 / 4 wavelength plate. The elliptical polarizer is a functional layer that allows only right-handed or left-handed circularly polarized light components to pass through by stacking a λ / 4 phase retardation plate on a linear polarizer. The elliptical polarizer of this invention may have a λ / 4 phase retardation layer on either side of the polarizing film of this invention.

[0249] The λ / 4 phase difference layer constituting the elliptical polarizer of the present invention preferably satisfies the optical properties represented by the following formulas (a), (b) and (c).

[0250] Re(450) / Re(550)≤1.00 (a)

[0251] 1.00≤Re(650) / Re(550) (b)

[0252] 120≤Re(550)≤180 (c)

[0253] [In the formula, Re(λ) represents the in-plane phase difference value at wavelength λnm of the retardation layer, Re = (nx(λ) - ny(λ)) × d (d represents the thickness of the retardation layer, nx represents the principal refractive index at wavelength λnm in the direction parallel to the plane of the retardation layer within the refractive index ellipsoid formed by the retardation layer, and ny represents the refractive index at wavelength λnm in the direction parallel to the plane of the retardation layer and orthogonal to the aforementioned nx direction within the refractive index ellipsoid formed by the retardation layer).]

[0254] When the phase retardation layer satisfies equations (a) and (b), the phase retardation layer exhibits so-called inverse wavelength dispersion, that is, the in-plane phase difference value at short wavelengths is smaller than the in-plane phase difference value at long wavelengths. From the perspective of improving inverse wavelength dispersion and easily further improving optical properties when assembled into image display devices, etc., Re(450) / Re(550) is preferably 0.70 or more, more preferably 0.78 or more, and preferably 0.92 or less, more preferably 0.90 or less, further preferably 0.87 or less, particularly preferably 0.86 or less, and particularly more preferably 0.85 or less. Furthermore, Re(650) / Re(550) is preferably 1.0 or more, more preferably 1.01 or more, and further preferably 1.02 or more.

[0255] The aforementioned phase retardation layer can be a stretched film that imparts a phase difference by stretching a polymer, or a cured liquid crystal layer formed from a cured liquid crystal composition containing a polymeric liquid crystal compound. These λ / 4 phase retardation layers can be suitably manufactured using materials and methods known in the art.

[0256] The thickness of the λ / 4 retardation layer is not particularly limited, and can be, for example, less than 100 μm. However, from the viewpoint of miniaturization in image display devices and the like, it is preferably 0.5 μm to 20 μm, and more preferably 1 μm to 3 μm. Such a very thin retardation layer with a thickness of 1 μm to 3 μm can be manufactured using a liquid crystal cured layer obtained by curing a polymeric liquid crystal compound in a state where the compound is oriented.

[0257] When the polarizing film of the present invention is stacked with a λ / 4 retardation layer, it is preferable to stack them such that the slow axis (optical axis) of the λ / 4 retardation layer is substantially at 45° to the absorption axis of the polarizer. By stacking the slow axis (optical axis) of the retardation layer with the absorption axis of the polarizer substantially at 45°, the function of an elliptical polarizer can be obtained. It should be noted that "substantially at 45°" is generally in the range of 45 ± 5°.

[0258] The elliptical polarizer of the present invention can have the same configuration as conventional elliptical polarizers and / or retardation films. Examples of such configurations include, for instance, an adhesive layer (sheet) for attaching the elliptical polarizer to a display element of an optical display, and a protective film used to protect the surfaces of the polarizer and retardation layer from damage and contamination.

[0259] The elliptical polarizing plate of the present invention can be used in various display devices.

[0260] A display device is a device having display elements, including light-emitting elements or light-emitting devices as light sources. Examples of display devices include: liquid crystal display devices, organic electroluminescent (EL) display devices, inorganic electroluminescent (EL) display devices, flexible image display devices, touch panel display devices, electron emission display devices (e.g., field emission display devices (FED), surface field emission display devices (SED)), electronic paper (display devices using electronic ink or electrophoretic elements), plasma display devices, projection display devices (e.g., grating light valve (GLV) display devices, display devices with digital micromirror devices (DMD)), and piezoelectric ceramic displays, etc. Liquid crystal display devices include any of the following: transmissive liquid crystal display devices, semi-transmissive liquid crystal display devices, reflective liquid crystal display devices, direct-viewing liquid crystal display devices, and projection liquid crystal display devices. These display devices can be display devices for displaying two-dimensional images or stereoscopic display devices for displaying three-dimensional images. In particular, the elliptical polarizing plate of the present invention can be suitably used in organic electroluminescent (EL) display devices.

[0261] In one embodiment of the present invention, the above-mentioned display device is preferably a flexible image display device. The present invention also includes a flexible image display device comprising the elliptical polarizing plate of the present invention.

[0262] The flexible image display device having the elliptical polarizing plate of the present invention preferably also has a viewing window and a touch sensor.

[0263] A flexible image display device is formed, for example, of a flexible image display device laminate and an organic EL display panel. The flexible image display device laminate is positioned on the viewing side relative to the organic EL display panel and is configured in a bendable manner. In addition to the elliptical polarizing plate of the present invention described above, the flexible image display device laminate may also include a window, a touch sensor (for a touch panel), etc. Their stacking order is arbitrary, but it is preferable to stack them in the order of window, elliptical polarizing plate, and touch sensor, or in the order of window, touch sensor, and elliptical polarizing plate, starting from the viewing side.

[0264] When an elliptical polarizing plate is present on the viewing side of the touch sensor, the pattern of the touch sensor becomes less visually discernible, and the visual recognizability of the displayed image becomes better, which is therefore preferred. The various components can be laminated using adhesives, bonding agents, or the like. Furthermore, the laminate for the flexible image display device can have a light-shielding pattern formed on at least one side of any one of the aforementioned layers: the viewing window, the elliptical polarizing plate, and the touch sensor.

[0265] The viewing window, positioned on the viewing side of the flexible image display device, serves to protect other components from external impacts or environmental changes such as temperature and humidity. Conventionally, glass has been used as such a protective layer; however, the viewing window in a flexible image display device is not a rigid and hard material like glass, but rather possesses flexible properties. The aforementioned viewing window is formed from a flexible, transparent substrate, and may also include a hard coating on at least one side.

[0266] There are no particular limitations on the windows, touch sensors, etc., which constitute the laminate of the flexible image display device, and any previously known items can be used.

[0267] Example

[0268] The present invention will now be described in more detail based on embodiments and comparative examples, but the present invention is not limited to the following embodiments. Unless otherwise specified, "%" and "parts" in the examples refer to mass % and mass parts, respectively.

[0269] 1. Example 1

[0270] (1) Preparation of composition for photo-alignment film formation

[0271] The copolymer (1) (polymer) is prepared by the following steps.

[0272] Copolymer (1)

[0273] [Chemical Formula 14]

[0274]

[0275] A solution of 4-((6-(methacryloyloxy)hexyl)oxy)benzoic acid dissolved in toluene with an amine catalyst was added dropwise, and the mixture was heated to 40°C to carry out the reaction. The reaction solution was then cooled and water was added. A 50% aqueous acetic acid solution was added to the separated organic layer, and the mixture was stirred. The separated organic layer was concentrated to obtain methoxymethyl 4-((6-(methacryloyloxy)hexyl)oxy)benzoate.

[0276] 8.8 g (25.2 mmol) of methoxymethyl 4-((6-(methacryloyloxy)hexyl)oxy)benzoate, 1.0 g (3.6 mmol) of 6-(4-hydroxyphenoxy)hexyl methacrylate, 3.2 g (7.2 mmol) of (E)-3-(4-methoxyphenyl)acrylate 4-((6-(methacryloyloxy)hexyl)oxy)phenyl ester, and 0.2 g of 2,2'-azobis(2,4-dimethylpentanonitrile) were dissolved in tetrahydrofuran. Nitrogen gas was bubbled into the solution for 1 hour, and the reaction was carried out by heating at 60 °C. The reaction solution was then cooled to room temperature. 1.1 g (3.6 mmol) of 4-((6-(methacryloyloxy)hexyl)oxy)benzoic acid and 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride were added to the reaction solution to obtain a mixture. The mixture was heated to 40°C to carry out the reaction, and then the reaction solution was cooled. Methanesulfonic acid was added to the reaction solution at room temperature, and the mixture was heated to 70°C. The reaction solution was then cooled to near room temperature. The cooled reaction solution was added dropwise to n-hexane to form a precipitate. The precipitate was recovered and dried under reduced pressure to obtain the polymer (hereinafter, the polymer obtained in this example is sometimes referred to as "copolymer (1)"). It should be noted that the weight-average molecular weight of copolymer (1) was determined using GPC. The results are shown in Table 1.

[0277] It should be noted that (E)-3-(4-methoxyphenyl)acrylate 4-((6-(methacryloyloxy)hexyl)oxy)phenyl ester (the monomer of the derived structural unit (i)) and 4-((6-(methacryloyloxy)hexyl)oxy)benzoic acid (the monomer of the derived structural unit (iii)) are prepared by the following steps.

[0278] Monomer of the derived structural unit (i); (E)-3-(4-methoxyphenyl)acrylate 4-((6-(methacryloyloxy)hexyl)oxy)phenyl ester

[0279] [Chemical Formula 15]

[0280]

[0281] 6-(4-hydroxyphenoxy)-1-bromohexane was synthesized by heating 1,4-dihydroxybenzene and 1,6-dibromohexane under alkaline conditions.

[0282] Lithium methacrylate was reacted with the product to synthesize 6-(4-hydroxyphenoxy)hexyl methacrylate.

[0283] Under alkaline conditions, p-methoxycinnamoyl chloride was added to the product to synthesize (E)-3-(4-methoxyphenyl)acrylate 4-((6-(methacryloyloxy)hexyl)oxy)phenyl ester.

[0284] Monomer of derived structural unit (iii); 4-((6-(methacryloyloxy)hexyl)oxy)benzoic acid

[0285] [Chemical Formula 16]

[0286]

[0287] The method described in Makromol. Chem., 190, pp. 2255-2268, 1989 was used to synthesize methacryloyl chloride as a starting material.

[0288] Next, 2 parts of the obtained copolymer (1) and 98 parts of o-xylene were mixed and stirred at 80°C for 1 hour to obtain a composition for photo-oriented film formation.

[0289] (2) Preparation of a composition for forming a polarizer

[0290] The following components were mixed and stirred at 80°C for 1 hour to obtain a composition for forming a polarizer. The azo pigment described in the examples of Japanese Patent Application Publication No. 2013-101328 was used as the dichroic pigment.

[0291] 75 parts of the polymeric liquid crystal compound represented by formula (A-6)

[0292] [Chemical Formula 17]

[0293]

[0294] • 25 parts of the polymeric liquid crystal compound represented by formula (A-7)

[0295] [Chemical Formula 18]

[0296]

[0297] • 2.8 parts of the dichroic pigment (1) shown below

[0298] [Chemical Formula 19]

[0299]

[0300] • 2.8 parts of the dichroic pigment (2) shown below

[0301] [Chemical Formula 20]

[0302]

[0303] • The dichroic pigment (3) shown below is 2.8 parts

[0304] [Chemical Formula 21]

[0305]

[0306] • Polymerization initiator: 6 parts of 2-dimethylamino-2-benzyl-1-(4-morpholinophenyl)butane-1-one (Irgacure 369; manufactured by Ciba Specialty Chemicals Inc.)

[0307] Leveling agent: 1.2 parts of polyacrylate compound (BYK-361N; manufactured by BYK-Chemie).

[0308] Solvent: 250 parts of cyclopentanone

[0309] (3) Fabrication of polarizing plates

[0310] A cellulose triacetate membrane (KONICA MINOLTA KC4UY-TAC, 40 μm thick) was cut into quadrilaterals and treated once using a corona treatment apparatus (AGF-B10; Kasuga Electric Co., Ltd.) at an output power of 0.3 kW and a processing speed of 3 m / min. The aforementioned photo-alignment film forming composition was then coated onto the corona-treated surface using a bar coater, dried at 80°C for 1 minute, and irradiated with polarized UV light (SPOT CURE SP-7 with polarizer unit; USHIO INC.) at 100 mJ / cm². 2 The accumulated light intensity was used to expose the film to polarized UV light to form an optical alignment film. The thickness of the obtained optical alignment film was measured using an Ellipsometer M-220 (manufactured by Japan Spectrophotometer Co., Ltd.), and the result was 100 nm.

[0311] After coating the obtained photo-alignment film with the polarizer-forming composition using a bar coater, it is dried in a drying oven set to 100°C for 1 minute.

[0312] Then, using a high-pressure mercury lamp (UniQure VB-15201BY-A, manufactured by USHIO INC.), ultraviolet light was applied (under a nitrogen atmosphere, wavelength: 365nm, cumulative light intensity at 365nm: 1000mJ / cm²). 2 This process forms a polarizer in which the polymeric liquid crystal compound and dichroic pigment are oriented, resulting in a polarizing plate (1) formed from a substrate / photoalignment film / polarizer. At this point, the thickness of the polarizer is measured using an Ellipsometer, and the result is 1.0 μm.

[0313] (4) Characteristic Evaluation

[0314] [Evaluation of fit]

[0315] The adhesion between the polarizer and the photo-alignment film in the obtained polarizing plate (1) is evaluated using the following method.

[0316] (Crosshatch experiment)

[0317] The adhesion between the photo-alignment film and the polarizer in the obtained polarizing plate (1) was evaluated according to the cross-scribing test (the "checkerboard adhesion test" in JIS D0202-1988). A checkerboard pattern was created on the polarizer surface of the polarizing plate (1) by scribing lines at 2mm intervals in a 10×10 grid pattern, penetrating to both the polarizer and the photo-alignment film. Adhesive tape (25mm wide, made by Nichiban) was then completely adhered to the created checkerboard surface. Next, the adhesive tape was peeled off along a direction at a 90° angle to the surface.

[0318] The number of unpeeled checkerboard patterns was measured, and the adhesion was evaluated according to the following criteria. It should be noted that for the peeled checkerboard patterns, X-ray photoelectron spectroscopy (XPS) confirmed that the peeling interface was between the photo-alignment film and the polarizer. The results are shown in Table 1.

[0319] <Evaluation Criteria>

[0320] 〇: More than 90

[0321] △: 80 to 89

[0322] ×: 79 or less

[0323] [Evaluation of Orientation]

[0324] For the obtained polarizing plate (1), after setting it to an orthogonal Nicol configuration with respect to the backlight source, the orientation state of the polarizer was visually confirmed, and the orientation was evaluated according to the following criteria. In addition, samples were prepared separately using the same method and dried in a drying oven at 110°C and 120°C for 1 minute, and then evaluated. The results are shown in Table 1.

[0325] <Evaluation Criteria>

[0326] 〇: There is no orientation disorder.

[0327] ×: Orientation disorder, or no orientation

[0328] 2. Examples 2-7 and Comparative Example 1

[0329] Except for changing the composition of the polymer forming the photo-alignment film as shown in Table 1, polarizing plates were prepared in the same manner as in Example 1, and the adhesion and orientation were evaluated. The results are shown in Table 1. In Table 1, the polymers prepared in Examples 2 to 7 are referred to as copolymers (2) to copolymers (7), respectively, and the polymer prepared in Comparative Example 1 is referred to as copolymer (8).

[0330] It should be noted that the structures of structural unit (i), structural unit (ii), and structural unit (iii) are derived from the structures described below.

[0331] Structural unit (i)

[0332] [Chemical Formula 22]

[0333]

[0334] Structural unit (ii)

[0335] [Chemical Formula 23]

[0336]

[0337] Structural unit (iii)

[0338] [Chemical Formula 24]

[0339]

[0340] [Table 1]

[0341]

[0342] As shown in Table 1, it was confirmed that the polarizer and photoalignment film of the polarizing plates obtained in Examples 1 to 7 had high adhesion. In contrast, the polarizer and photoalignment film of the polarizing plate obtained in Comparative Example 1 had insufficient adhesion.

Claims

1. A polarizing film, which is a polarizing film comprising a photo-alignment film and a polarizer adjacent to the photo-alignment film, The photo-alignment film is formed of a polymer comprising a structural unit having a photoreactive group and a structural unit having a polymerizable group, The polymer forming the photo-alignment film has a repeating unit represented by formula (II), [Chemical formula 1] In formula (II), Ma, Mb and Mc each independently represent a molecular chain forming the main chain of the polymer; m, n and l represent the molar fractions of the polymer, and in any case, 0 < m < 1, 0 < n < 1 and 0 < l < 1; SPCRa, SPCRb and SPCRc each independently represent a divalent group; Ring A, ring B and ring C are each independently an unsubstituted or substituted alicyclic hydrocarbon or an unsubstituted or substituted aromatic ring; X is a single bond, an alkylene chain having 1 to 10 carbon atoms, or a cycloalkylene chain having 3 to 8 carbon atoms; Y is -O-CO-CH=CH2- or -N=N-, and in -O-CO-CH=CH2-, any connecting bond can be bonded to ring B; Z is selected from the group consisting of a single bond; an alkylene chain having 1 to 10 carbon atoms which is unsubstituted or substituted with a hydroxyl group and / or a carbonyl group; a cycloalkylene chain having 3 to 8 carbon atoms; -O-; -COO-; and combinations thereof; R 1 It is an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a phenyl group having at least one substituent selected from cyano and halogen atoms; R 2 The formula is -CW=CH2 or -V-CW=CH2, where W is a hydrogen atom or a methyl group, and V is -O-CO- or -CO-. The polymer forming the photo-alignment film has a weight-average molecular weight of 20,000 or more and 150,000 or less, The polarizer is a cured product of a liquid crystal composition comprising a liquid crystal compound and a dichroic dye, and comprises a structural unit having a polymerizable group derived from the liquid crystal compound or the dichroic dye.

2. The polarizing film as described in claim 1, wherein, The photoreactive group is a group capable of undergoing a dimerization reaction or an isomerization reaction.

3. The polarizing film as described in claim 1 or 2, wherein, The polymer forming the photo-alignment film further comprises a structural unit having a carboxyl group.

4. The polarizing film according to any one of claims 1 to 3, wherein, The dichroic dye comprises an azo dye.

5. The polarizing film according to any one of claims 1 to 4, wherein, The polarizer comprises a polymer of a polymerizable liquid crystal compound.

6. The polarizing film according to any one of claims 1 to 5, wherein, The polarizer shows a Bragg peak in X-ray diffraction measurement.

7. A polarizing plate, which comprises the polarizing film according to any one of claims 1 to 6, and a substrate disposed on the photo-alignment film side of the polarizing film.

8. An optical laminate, which comprises the polarizing plate according to claim 7, and a layer laminated on the polarizer side of the polarizing plate through an adhesive bonding layer.

9. A circular polarizing plate, which comprises the polarizing film according to any one of claims 1 to 6 and a retardation layer having a quarter-wave plate function.

10. An organic EL display device, which comprises the circular polarizing plate according to claim 9.

11. A flexible image display device, which comprises the circular polarizing plate according to claim 9.

12. The flexible image display device according to claim 11, which further comprises a window and a touch sensor.

Images