Light absorbing anisotropic plate

Abstract

The present invention relates to a light-absorbing anisotropic sheet. The object is to provide a light-absorbing anisotropic sheet comprising a vertical alignment type light-absorbing anisotropic film which is less likely to be damaged by application of force. A light-absorbing anisotropic sheet comprising a film substrate and a light-absorbing anisotropic film, the light-absorbing anisotropic film being a cured film of a liquid crystal composition comprising a polymerizable liquid crystal compound, a non-liquid crystal compound containing a reactive group, and a dichroic pigment, and being a cured film in which the polymerizable liquid crystal compound and the dichroic pigment are cured in a state of being aligned in a vertical direction with respect to the plane of the light-absorbing anisotropic film.

Description

Technical Field

[0001] This invention relates to anisotropic light-absorbing plates and a method for manufacturing such plates. Background Technology

[0002] As a light-absorbing anisotropic film for providing privacy protection for displays of mobile phones, bank ATMs, etc., a light-absorbing anisotropic film is known to be manufactured by coating a liquid crystal composition comprising a dichroic pigment and a liquid crystal compound onto a substrate, such that the liquid crystal compound and the dichroic pigment are perpendicularly oriented relative to the film plane (Patent Document 1).

[0003] Existing technical documents

[0004] Patent documents

[0005] Patent Document 1: Japanese Patent Application Publication No. 2016-27387 Summary of the Invention

[0006] The problem that the invention aims to solve

[0007] On the other hand, for light-absorbing anisotropic films in which liquid crystal compounds and dichroic pigments are oriented perpendicularly to the film plane, it is required that the film is not easily damaged when force is applied.

[0008] The purpose of this invention is to provide a light-absorbing anisotropic plate containing a vertically oriented light-absorbing anisotropic film that is not easily damaged when force is applied.

[0009] Methods for solving problems

[0010] The inventors of this application conducted in-depth research to solve the aforementioned problems, resulting in the completion of this invention. Specifically, this invention includes the following aspects.

[0011] [1] Anisotropic light-absorbing plate, comprising a film substrate and anisotropic light-absorbing film,

[0012] The aforementioned light-absorbing anisotropic film is a cured film of a liquid crystal composition comprising a polymeric liquid crystal compound, a non-liquid crystal compound containing reactive groups, and a dichroic pigment, and is a cured film formed by curing the polymeric liquid crystal compound and the dichroic pigment in a state of orientation perpendicular to the plane of the light-absorbing anisotropic film.

[0013] [2] The light-absorbing anisotropic plate as described in [1] above, wherein the non-liquid crystal compound containing reactive groups has at least one reactive group selected from acryloyloxy and methacryloyloxy.

[0014] [3] The light-absorbing anisotropic plate as described in [1] or [2] above, wherein the non-liquid crystal compound containing reactive groups is at least one selected from monofunctional (meth)acrylates and polyfunctional (meth)acrylates.

[0015] [4] The light-absorbing anisotropic plate as described in any one of [1] to [3] above, wherein the non-liquid crystal compound containing reactive groups has 2 or more but less than 12 reactive groups in its molecule.

[0016] [5] The light-absorbing anisotropic plate as described in any one of [1] to [4] above, wherein the reactive group of the non-liquid crystal compound containing the reactive group is the same as the polymeric group of the polymeric liquid crystal compound.

[0017] [6] The light-absorbing anisotropic plate as described in any one of [1] to [5] above, wherein the content of the non-liquid crystal compound containing reactive groups is 0.2 parts by mass or more and 15 parts by mass or less, relative to 100 parts by mass of the polymeric liquid crystal compound.

[0018] [7] The light-absorbing anisotropic plate as described in any one of [1] to [6] above, wherein the polymeric liquid crystal compound is a liquid crystal compound exhibiting a smectic liquid crystal phase.

[0019] [8] The light-absorbing anisotropic plate as described in any one of [1] to [7] above, wherein the dichroic pigment is an azo pigment.

[0020] [9] The light-absorbing anisotropic plate as described in any one of [1] to [8] above, wherein the thickness of the light-absorbing anisotropic film is less than 2 μm.

[0021]

[10] The light-absorbing anisotropic plate as described in any one of [1] to [9] above, wherein the light-absorbing anisotropic film exhibits a Bragg peak in X-ray diffraction measurements.

[0022]

[11] The light-absorbing anisotropic plate as described in any one of [1] to

[10] above, wherein the film substrate is a resin film composed of at least one selected from the group consisting of polyimide resin, cellulose ester resin, cyclic olefin resin, polyester resin and poly(meth)acrylic acid resin.

[0023]

[12] The light-absorbing anisotropic plate as described in any one of [1] to

[11] above, wherein the film substrate is adjacent to the light-absorbing anisotropic film.

[0024]

[13] A method for manufacturing a light-absorbing anisotropic plate, wherein the light-absorbing anisotropic plate comprises a film substrate and a light-absorbing anisotropic film, the manufacturing method comprising the following steps:

[0025] A process of forming a coating film on a film substrate comprising a polymeric liquid crystal compound, a non-liquid crystal compound containing reactive groups, and a dichroic pigment;

[0026] The process of drying the resulting coating to obtain a dried coating; and,

[0027] A process for curing the polymeric liquid crystal compound and dichroic pigment in the above-mentioned dry coating film in a state of orientation perpendicular to the plane of the coating film.

[0028]

[14] The manufacturing method described above

[13] , wherein the light-absorbing anisotropic plate is elongated, and the manufacturing method includes the following steps:

[0029] The process of unwinding a long strip of film substrate that is wound into a roll and forming a coating film on the film substrate that comprises a polymeric liquid crystal compound, a non-liquid crystal compound containing reactive groups and a dichroic pigment.

[0030] A process of continuously drying the resulting coating film to obtain a dried coating film; and,

[0031] A process in which the polymeric liquid crystal compound and dichroic pigment in the above coating are oriented in a direction perpendicular to the plane of the coating and continuously irradiated with active energy rays, thereby curing the coating.

[0032]

[15] Display material comprising any one of the light-absorbing anisotropic plates described in any one of [1] to

[12] above.

[0033]

[16] A display device comprising any one of the light-absorbing anisotropic plates described in any one of [1] to

[12] above.

[0034] The effects of the invention

[0035] According to the present invention, it is possible to provide a light-absorbing anisotropic plate comprising a vertically oriented light-absorbing anisotropic film that is not easily damaged when force is applied. Detailed Implementation

[0036] 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.

[0037] The light-absorbing anisotropic plate of the present invention comprises a film substrate and a light-absorbing anisotropic film.

[0038] <Anisotropic light-absorbing film>

[0039] In this invention, the light-absorbing anisotropic film is a cured film of a liquid crystal composition comprising a polymeric liquid crystal compound, a non-liquid crystal compound containing reactive groups, and a dichroic pigment, and is a cured film formed by curing the polymeric liquid crystal compound and the dichroic pigment in a state of orientation perpendicular to the plane of the light-absorbing anisotropic film.

[0040] In this invention, the polymerizable liquid crystal compound included in the liquid crystal composition for forming anisotropic light absorption films (hereinafter also referred to as "composition for forming anisotropic light absorption films") is a compound having at least one polymerizable group and exhibiting liquid crystal properties. Herein, a polymerizable group refers to a group that participates in a polymerization reaction, preferably a photopolymerizable group. A photopolymerizable group refers to a group that can participate in a polymerization reaction through active free radicals, acids, etc., generated by a polymerization initiator. Examples of polymerizable groups in the polymerizable liquid crystal compound include vinyl, vinyloxy, 1-chlorovinyl, isopropenyl, 4-vinylphenyl, acryloyloxy, methacryloyloxy, epoxyethyl, and oxetyl. Among these, free radical polymerizable groups are preferred, acryloyloxy, methacryloyloxy, vinyloxy, epoxyethyl, and oxetyl are more preferred, and acryloyloxy is even more preferred.

[0041] In this invention, the polymerizable liquid crystal compound is preferably a liquid crystal compound exhibiting a smectic liquid crystal phase. By using a polymerizable liquid crystal compound exhibiting a smectic liquid crystal phase, it is possible to form a light absorption anisotropic film with high orientation order and excellent polarization function in the tilt direction. From the viewpoint of achieving higher orientation order, the liquid crystal state displayed by the polymerizable liquid crystal compound (A) is more preferably a higher-order smectic phase (higher-order smectic liquid crystal state). The higher-order smectic phase refers to smectic phases B, D, E, F, G, H, I, J, K, and L, with smectic phases B, F, and I being more preferred. Regarding liquid crystal properties, it can be a thermotropic liquid crystal or a lyotropic liquid crystal, but from the perspective of precise film thickness control, a thermotropic liquid crystal is preferred. Furthermore, the polymerizable liquid crystal compound (A) can be a monomer or an oligomer or polymer formed by polymerizing polymeric groups.

[0042] As a polymerizable liquid crystal compound, any liquid crystal compound having at least one polymerizable group is acceptable, and there is no particular limitation. Known polymerizable liquid crystal compounds can be used, and compounds exhibiting smectic liquid crystal properties are preferred. For example, a compound represented by the following formula (A) (hereinafter also referred to as "polymerizable liquid crystal compound (A)") can be cited as such a polymerizable liquid crystal compound.

[0043] U 1 -V 1 -W1 -(X 1 -Y 1 ) n -X 2 -W 2 -V 2 -U 2 (A)

[0044] In formula (A),

[0045] X 1 and X 2 Each of the following groups independently represents a divalent aromatic group or a divalent alicyclic hydrocarbon group, wherein the hydrogen atom in the divalent aromatic group or divalent alicyclic hydrocarbon group can be substituted by a halogen atom, an alkyl group having 1 to 4 carbon atoms, a fluoroalkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a cyano group, or a nitro group, and the carbon atom constituting the divalent aromatic group or divalent alicyclic hydrocarbon group can be substituted by an oxygen atom, a sulfur atom, or a nitrogen atom. Wherein, X 1 and X 2 At least one of them is 1,4-phenylene, which may have substituents, or cyclohexane-1,4-diyl, which may have substituents.

[0046] Y 1 It is a single bond or a divalent linker.

[0047] When n is 1 to 3, and n is 2 or more, there are multiple X's. 1 They can be the same or different. X 2 Can be used with multiple X 1 Any one or all of them can be the same, or they can be different. Furthermore, when n is 2 or more, multiple Ys... 1 They can be the same or different. From the viewpoint of liquid crystal properties, n is preferably 2 or more.

[0048] U 1 It represents a hydrogen atom or a polymeric group.

[0049] U 2 It indicates a polymerizable group.

[0050] W 1 and W 2 The linking groups are either single bonds or divalent and are independent of each other.

[0051] V 1 and V 2 These can be independently represented as alkyldiyl groups with 1 to 20 carbon atoms that may have substituents, where the -CH2- group constituting the alkyldiyl group can be replaced by -O-, -CO-, -S-, or NH-.

[0052] In polymeric liquid crystal compound (A), X1 and X 2 The preferred alternatives are 1,4-phenylene, which may have substituents, or cyclohexane-1,4-diyl, which may have substituents. 1 and X 2 At least one of them is a 1,4-phenylene that may have a substituent, or a cyclohexane-1,4-diyl that may have a substituent, preferably trans-cyclohexane-1,4-diyl. Examples of substituents optionally present in the 1,4-phenylene that may have a substituent, or in the cyclohexane-1,4-diyl 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 is preferred.

[0053] Furthermore, from the viewpoint of easily exhibiting smectic liquid crystal properties, the polymeric liquid crystal compound (A) preferably has an asymmetric structure in the portion represented by formula (A1) in formula (A) [hereinafter also referred to as the partial structure (A1)].

[0054] -(X 1 -Y 1 ) n -X 2 - (A1)

[0055] [In the formula, X] 1 Y 1 X 2 And n respectively represent the same meaning as above.

[0056] As a polymeric liquid crystal compound (A) with a partially asymmetric structure (A1), examples include: n is 1 and there is 1 X 1 With X 2 Examples include polymeric liquid crystal compounds (A) with different structures. Additionally, another example is a polymeric liquid crystal compound (A) where n is 2 and there are 2 Y atoms. 1 Compounds with identical structures and two X's 1 For structures that are identical to each other, 1 X 2 With the above two X's 1 For different structures; polymeric liquid crystal compound (A), which has n=2 and 2 Y atoms 1 Compounds with identical structures and two X's 1 The bond in W 1 X 1 With another X 1 and X 2 For different structures, another X 1 With X 2 They have the same structure as each other. Furthermore, examples include polymeric liquid crystal compounds (A) with n = 3 and 3 Y atoms. 1Compounds with identical structures and three X's 1 And 1 X 2 Each of the three is a structure that is different from the other three.

[0057] Y 1 Preferred 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. 1 More preferably -CH2CH2-, -CH2O-, -COO-, -OCOO-, single bond, -N=N-, -CR a =CR b -、-C≡C- or -CR a =N-, more preferably -CH2CH2-, -COO-, -CH2O- or a single bond, in the presence of multiple Y 1 In the case of X, it is even more preferable to have X 2 Bonded Y 1 It is -CH2CH2- or -CH2O-, and is not related to X. 2 Bonded Y 1 It can be -CH2CH2-, -COO-, or a single bond. In X 1 and X 2 When all structures are identical, it is preferable to have two or more Y atoms with different bonding methods. 1 In the presence of multiple Ys with different bonding methods 1 In this case, it becomes an asymmetric structure, and therefore tends to exhibit smectic liquid crystal properties.

[0058] U 2 It is a polymerizable group. U 1 It is a hydrogen atom or a polymeric group, preferably a polymeric group. U is preferred. 1 and U 2 All are polymerizable groups, more preferably all are photopolymerizable groups, and even more preferably all are photoradical polymerizable groups. As polymerizable groups, examples can be the same groups exemplified above that are polymerizable groups present in polymerizable liquid crystal compounds. 1 The polymerizable group represented by U 2 The polymerizable groups represented may be different from each other, but are preferably of the same kind, preferably U. 1 and U 2At least one of them is (meth)acryloyloxy, more preferably both are (meth)acryloyloxy, and even more preferably both are acryloyloxy. Furthermore, the polymerizable group can be in a polymerized state or an unpolymerized state, but is preferably in an unpolymerized state.

[0059] As V 1 and V 2 Examples of alkyldiyl 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. 1 and V 2 Preferably, it is an alkyldiyl group with 2 to 12 carbon atoms, and more preferably an alkyldiyl group with 6 to 12 carbon atoms.

[0060] Examples of substituents that may be optionally present in the alkyl diester include cyano groups and halogen atoms such as chlorine atoms and fluorine atoms. The alkyl diester is preferably unsubstituted, and more preferably an unsubstituted straight-chain alkyl diester.

[0061] W 1 and W 2 The components are preferably single bonds, -O-, -S-, -COO-, or -OCOO-, and more preferably single bonds or -O-.

[0062] As for the structure of a polymeric liquid crystal compound that readily exhibits smectic liquid crystal properties, a molecular structure with asymmetry in its molecular structure is preferred. Specifically, a polymeric liquid crystal compound having partial structures (Aa) to (Ai) described below and exhibiting smectic liquid crystal properties is more preferred. From the viewpoint of readily exhibiting higher-order smectic liquid crystal properties, partial structures having (Aa), (Ab), or (Ac) are more preferred. It should be noted that in (Aa) to (Ai) described below, * indicates a connecting bond (single bond).

[0063] [Chemical Formula 1]

[0064]

[0065] Examples of polymerizable liquid crystal compounds (A) include those 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.

[0066] [Chemical Formula 2]

[0067]

[0068] [Chemical Formula 3]

[0069]

[0070] [Chemical Formula 4]

[0071]

[0072] [Chemical Formula 5]

[0073]

[0074] [Chemical Formula 6]

[0075]

[0076] Among these, at least one is preferably selected from the group consisting of compounds represented by free formula (A-2), formula (A-3), formula (A-4), formula (A-6), formula (A-7), formula (A-8), formula (A-13), formula (A-14), and formula (A-15). As a polymerizable liquid crystal compound (A), one can be used alone or in combination of two or more.

[0077] Polymerizable liquid crystal compound (A) can be manufactured, for example, by known methods described in Lub et al. Recl.Trav.Chim.Pays-Bas, 115, 321-328 (1996) or Japanese Patent No. 4719156.

[0078] In this invention, the light-absorbing anisotropic film is preferably formed by comprising a polymeric liquid crystal compound (A), and the composition for forming the light-absorbing anisotropic film preferably comprises a polymeric liquid crystal compound (A). When the composition for forming the light-absorbing anisotropic film contains two or more polymeric liquid crystal compounds, the proportion of polymeric liquid crystal compound (A) relative to the total mass of the polymeric liquid crystal compounds contained in the composition for forming the light-absorbing anisotropic film is preferably 51% by mass or more, more preferably 70% by mass or more, and even more preferably 90% by mass or more. When the proportion of polymeric liquid crystal compound (A) is within the above range, it is easy to obtain a light-absorbing anisotropic film with high orientation order.

[0079] When the composition for forming anisotropic light-absorbing films contains two or more polymeric liquid crystal compounds, at least one of them may be a polymeric liquid crystal compound (A), or all of them may be polymeric liquid crystal compounds (A). 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.

[0080] Regarding the content of the polymeric liquid crystal compound in the composition for forming anisotropic light absorption films, it is preferably 40 to 99.9% by mass, more preferably 60 to 99% by mass, and even more preferably 70 to 99% by mass, relative to the solid content of the liquid crystal composition. When the content of the polymeric liquid crystal compound is within the above range, there is a tendency for the orientation of the polymeric liquid crystal compound to become higher. It should be noted that, in this specification, the term "solid content" in the composition for forming anisotropic light absorption films refers to the total amount of the components remaining after removing volatile substances such as solvents from the composition. Hereinafter, the term "solid content" in other compositions, etc., also refers to the total amount of the components remaining after removing volatile substances such as solvents from the composition in question.

[0081] In this invention, a non-liquid crystal compound containing reactive groups refers to a compound having reactive groups (functional groups) capable of reacting with the polymeric groups of the aforementioned polymeric liquid crystal compound, and which does not exist in a liquid crystal state between solid and liquid even with temperature changes. Anisotropic light absorption films are formed from liquid crystal compositions containing non-liquid crystal compounds containing reactive groups, thereby improving the film strength and achieving high flexibility. In particular, according to the inventors' research, for liquid crystal cured films where the polymeric liquid crystal compounds are oriented perpendicularly to the film plane, the liquid crystal compounds are arranged in layers perpendicular to the film plane, making interlayer peeling prone to occur. However, by incorporating a non-liquid crystal compound containing reactive groups, this interlayer peeling can be suppressed. Especially in the case of cured films displaying (higher-order) smectic liquid crystal phases, there is a tendency for interlayer peeling to occur more easily when the liquid crystal compounds are oriented in a higher orientation order perpendicularly. Therefore, in addition to the improved film strength and flexibility resulting from incorporating a non-liquid crystal compound containing reactive groups, the suppression effect of interlayer peeling can be obtained more significantly.

[0082] The non-liquid crystal compound containing reactive groups is preferably a compound that: (I) is not colored (absorbs visible light); (II) has compatibility with the polymerizable liquid crystal compound to a degree that allows for uniform mixing; and (III) does not hinder the formation of the liquid crystal state displayed by the polymerizable liquid crystal compound.

[0083] The reactive groups in a non-liquid crystal compound include, for example, reactive groups that can crosslink or polymerize with polymerizable liquid crystal compounds through free radical reactions, and / or that can further crosslink or polymerize with each other. Specifically, examples include vinyl, vinyloxy, 1-chlorovinyl, isopropenyl, 4-vinylphenyl, acryloyloxy, methacryloxy, epoxyethyl, oxetyl, thiol, and isocyanate groups. The reactive groups are preferably polymerizable groups, more preferably free radical polymerizable groups. Among these, acryloyloxy, methacryloxy, vinyloxy, epoxyethyl, and oxetyl are more preferred, and acryloyloxy and methacryloxy are even more preferred.

[0084] In this invention, the non-liquid crystal compound containing reactive groups preferably has at least one reactive group (polymerizable group) selected from acryloyloxy and methacryloyloxy. By including a non-liquid crystal compound containing reactive groups having at least one reactive group selected from acryloyloxy and methacryloyloxy, the film strength of the obtained liquid crystal cured film can be easily improved, and interlayer delamination in vertically oriented liquid crystal cured films can be easily suppressed.

[0085] Examples of non-liquid crystal compounds containing reactive groups include monofunctional (meth)acrylates and polyfunctional (meth)acrylates. Monofunctional means having one reactive group, and polyfunctional means having multiple reactive groups. In this invention, the non-liquid crystal compound containing reactive groups constituting the light-absorbing anisotropic film is preferably selected from at least one of monofunctional (meth)acrylates and polyfunctional (meth)acrylates, more preferably from at least one of monofunctional and polyfunctional acrylates. From the viewpoint of facilitating the continuous polymerization reaction of the polymerizable liquid crystal compound and the non-liquid crystal compound containing reactive groups, polyfunctional acrylates are further preferred. As a non-liquid crystal compound containing reactive groups, one type can be used alone, or two or more types can be used in combination. It should be noted that in this specification, (meth)acrylate refers to acrylate or methacrylate, and the same applies to (meth)acryloyloxy groups, etc. Furthermore, regarding the aforementioned monofunctional (meth)acrylates and polyfunctional (meth)acrylates, from the viewpoint of exhibiting non-liquid crystal properties, it is preferable that they do not have a mesocrystalline structure. Furthermore, in the coating of the light absorption anisotropic film forming composition, urethane structure, amino structure, epoxy structure, ethylene glycol structure and polyester structure can be included intramolecularly without disturbing the liquid crystal phase of the polymerizable liquid crystal compound contained therein, especially the smectic liquid crystal phase.

[0086] Monofunctional (meth)acrylates are compounds that have one (meth)acryloyloxy group in the molecule [i.e., acryloyloxy (CH2=CHCOO-) or methacryloyloxy (CH2=C(CH3)COO-)].

[0087] Examples of monofunctional (meth)acrylates having one (meth)acryloyloxy group include alkyl esters of (meth)acrylate with 4 to 16 carbon atoms, β-carboxyalkyl esters of (meth)acrylate with 2 to 14 carbon atoms, alkylated phenyl esters of (meth)acrylate with 2 to 14 carbon atoms, methoxy polyethylene glycol (meth)acrylate, phenoxy polyethylene glycol (meth)acrylate, and isobornyl methacrylate.

[0088] Polyfunctional (meth)acrylates refer to compounds having two or more (meth)acryloyloxy groups within the molecule. In this invention, the polyfunctional (meth)acrylates used as non-liquid crystal compounds containing reactive groups preferably have 2 to 8 (meth)acryloyloxy groups within the molecule.

[0089] Examples of difunctional (meth)acrylates having two (meth)acryloyloxy groups include: 1,3-butanediol di(meth)acrylate; 1,3-butanediol (meth)acrylate; 1,6-hexanediol di(meth)acrylate; ethylene glycol di(meth)acrylate; diethylene glycol di(meth)acrylate; neopentyl glycol di(meth)acrylate; triethylene glycol di(meth)acrylate; tetraethylene glycol di(meth)acrylate; polyethylene glycol diacrylate; bis(acryloyloxyethyl) ether of bisphenol A; ethoxylated bisphenol A di(meth)acrylate; propoxylated neopentyl glycol di(meth)acrylate; ethoxylated neopentyl glycol di(meth)acrylate and 3-methylpentyl glycol di(meth)acrylate; etc.

[0090] Examples of polyfunctional (meth)acrylates having 3 to 6 (meth)acryloyloxy groups include:

[0091] Trimethylolpropane tri(meth)acrylate; Pentaerythritol tri(meth)acrylate; Tris(2-hydroxyethyl)isocyanurate tri(meth)acrylate; Ethoxylated trimethylolpropane tri(meth)acrylate; Propoxylated trimethylolpropane tri(meth)acrylate; Pentaerythritol tetra(meth)acrylate; Dipentaerythritol penta(meth)acrylate; Dipentaerythritol hexa(meth)acrylate; Tripentaerythritol tetra(meth)acrylate; Tripentaerythritol penta(meth)acrylate; Tripentaerythritol hexa(meth)acrylate; Tripentaerythritol hepta(meth)acrylate; Tripentaerythritol octa(meth)acrylate;

[0092] The reaction products of pentaerythritol tri(meth)acrylate and acid anhydride; the reaction products of dipentaerythritol penta(meth)acrylate and acid anhydride; the reaction products of tripentaerythritol hepta(meth)acrylate and acid anhydride;

[0093] Caprolactone-modified trimethylolpropane tri(meth)acrylate; caprolactone-modified pentaerythritol tri(meth)acrylate; caprolactone-modified tri(2-hydroxyethyl)isocyanurate tri(meth)acrylate; caprolactone-modified pentaerythritol tetra(meth)acrylate; caprolactone-modified dipentaerythritol penta(meth)acrylate; caprolactone-modified dipentaerythritol hexa(meth)acrylate; caprolactone-modified tripentaerythritol tetra(meth)acrylate; caprolactone-modified tripentaerythritol tetra(meth)acrylate. Caprolactone-modified pentaerythritol pentamethacrylate; caprolactone-modified pentaerythritol hexamethacrylate; caprolactone-modified pentaerythritol heptamethacrylate; caprolactone-modified pentaerythritol octamethacrylate; caprolactone-modified pentaerythritol trimethacrylate reacting with acid anhydrides; caprolactone-modified dipentaerythritol pentamethacrylate reacting with acid anhydrides; and caprolactone-modified pentaerythritol heptamethacrylate reacting with acid anhydrides; etc. It should be noted that caprolactone modification refers to the introduction of an open-ring form of caprolactone, or an open-ring polymer, between the alcohol-derived portion and the (meth)acryloyloxy group of a (meth)acrylate compound.

[0094] Examples of polyfunctional (meth)acrylates having seven or more (meth)acryloyloxy groups include: pentaerythritol hepta(meth)acrylate; pentaerythritol octa(meth)acrylate; reactants of pentaerythritol hepta(meth)acrylate with acid anhydrides; caprolactone-modified pentaerythritol hepta(meth)acrylate; caprolactone-modified pentaerythritol octa(meth)acrylate; reactants of caprolactone-modified pentaerythritol hepta(meth)acrylate with acid anhydrides; and so on.

[0095] Commercially available multifunctional (meth)acrylates can also be used as non-liquid crystal compounds containing reactive groups. Examples of such commercially available products include, for instance, A-DOD-N, A-HD-N, A-NOD-N, APG-100, APG-200, APG-400, A-GLY-9E, A-GLY-20E, A-TMM-3, A-TMPT, AD-TMP, ATM-35E, A-TMMT, A-9550, A-DPH, HD-N, NOD-N, NPG, TMPT (all manufactured by Shin-Nakamura Chemical Co., Ltd.), ARONIX M-220, ARONIX M-325, ARONIX M-240, ARONIX M-270, ARONIX M-309, ARONIX M-310, ARONIX M-321, ARONIX M-350, ARONIX M-360, ARONIX M-305, ARONIX M-306, and ARONIX M-306. M-450, ARONIX M-451, ARONIX M-408, ARONIX M-400, ARONIX M-402, ARONIX M-403, ARONIX M-404, ARONIX M-405, ARONIX M-406 (all manufactured by Toa Gosei Co., Ltd.), EBECRYL11, EBECRYL145, EBECRYL150, EBECRYL40, EBECRYL140, EBECRYL180, DPGDA, HDDA, TPGDA, HPNDA, PETIA, PETRA, TMPTA, TMPEOTA, DPHA, EBECRYL series (all manufactured by Daicel-Cytec Co., Ltd.), etc.

[0096] Preferred polyfunctional (meth)acrylates include compounds represented by formulas (B-1) to (B-14) below.

[0097] [Chemical Formula 7]

[0098]

[0099] The non-liquid crystal compound containing reactive groups preferably has 2 to 12 reactive groups within its molecule, more preferably 2 to 12 polymeric groups within its molecule, and even more preferably a polyfunctional (meth)acrylate having 2 to 12 polymeric groups within its molecule. From the viewpoint of more easily improving film strength, the number of reactive groups (number of polymeric groups) in the non-liquid crystal compound containing reactive groups is preferably 3 or more per molecule, more preferably 4 or more, and even more preferably 5 or more. Furthermore, from the viewpoint of achieving a well-balanced and moderate film strength, a highly oriented liquid crystal cured film with excellent flexibility, suppression of interlayer peeling, and high polarization function in the tilt direction, the number of polymeric groups in the non-liquid crystal compound containing reactive groups is preferably 10 or less per molecule, more preferably 9 or less, and even more preferably 8 or less.

[0100] In this invention, the reactive groups (polymerizable groups) of the non-liquid crystal compound containing reactive groups are preferably the same as the polymerizable groups of the polymerizable liquid crystal compound. It should be noted that when at least one compound selected from the polymerizable liquid crystal compound and the non-liquid crystal compound containing reactive groups has multiple reactive groups, it is preferable that at least one polymerizable group of the polymerizable liquid crystal compound is the same as at least one reactive group of the non-liquid crystal compound containing reactive groups. For example, when the non-liquid crystal compound containing reactive groups is a monofunctional (meth)acrylate, it is preferable that the polymerizable liquid crystal compound also has a (meth)acryloyloxy group. When the non-liquid crystal compound containing reactive groups is a polyfunctional (meth)acrylate, it is preferable that the polymerizable liquid crystal compound also has a (meth)acryloyloxy group.

[0101] Relative to 100 parts by mass of the polymeric liquid crystal compound constituting the anisotropic light absorption film, the content of the non-liquid crystal compound containing reactive groups in the anisotropic light absorption film is preferably 0.2 parts by mass or more and 15 parts by mass or less. When the content of the non-liquid crystal compound containing reactive groups is within the above range, the non-liquid crystal compound containing reactive groups is less likely to disrupt the orientation of the polymeric liquid crystal compound and the dichroic pigment, and can easily improve the film strength while having high polarization function. From the viewpoint of more easily obtaining an anisotropic light absorption film with excellent balance between appropriate film strength and orientation order of polymeric liquid crystal compound, exhibiting high film strength and flexibility, and excellent polarization function, the content of the non-liquid crystal compound containing reactive groups is more preferably 0.5 parts by mass or more, further preferably 1 part by mass or more, particularly preferably 1.2 parts by mass or more, and even more preferably 12 parts by mass or less, further preferably 10 parts by mass or less, particularly preferably 9 parts by mass or less, and particularly preferably 8 parts by mass or less.

[0102] Dichroic pigments are pigments that possess the following properties: the absorbance along the long axis of the molecule differs from the absorbance along the short axis. The dichroic pigments used in this invention only need to possess the above properties; there are no particular limitations. They can be dyes or pigments. Furthermore, two or more dyes or pigments can be combined individually, or dyes and pigments can be used in combination. Additionally, dichroic pigments can exhibit polymerizability or liquid crystal properties.

[0103] As a dichroic pigment, it is preferably one that has a maximum absorption wavelength (λ) in the wavelength range of 300–700 nm in anisotropic light-absorbing films. MAX ( ) is a dichroic pigment.

[0104] Examples of such dichroic pigments include acridine pigments, oxazine pigments, anthocyanin pigments, naphthalene pigments, azo pigments, and anthraquinone pigments. Among these, azo pigments are preferred. Examples of azo pigments include monoazo pigments, diazo pigments, triazo pigments, tetraazo pigments, and succinylazo pigments, with diazo pigments and triazo pigments being the most preferred.

[0105] As an azo dye, for example, compounds represented by formula (I) (hereinafter also referred to as "compound (I)") can be cited.

[0106] K 1 (-N=NK) 2 ) p -N=NK 3 (I)

[0107] In formula (I), K 1 and K 3Each can independently represent a phenyl group that may have a substituent, a naphthyl group that may have a substituent, a phenyl benzoate group that may have a substituent, or a monovalent heterocyclic group that may have a substituent. K 2 This indicates a substituent-containing p-phenylene, a substituent-containing naphth-1,4-diyl, a substituent-containing 4,4'-pyridylene, or a substituent-containing divalent heterocyclic group. p represents an integer from 0 to 4. When p is two or more integers, multiple K... 2 They can be the same or different. Within the visible light absorption range, -N=N- bonds can be replaced by -C=C-, -COO-, -NHCO-, or -N=CH- bonds.

[0108] Examples of monovalent heterocyclic groups include those obtained by removing one hydrogen atom from heterocyclic compounds such as quinoline, thiazole, benzothiazole, thienothiazole, imidazole, benzimidazole, oxazole, and benzoxazole. Examples of divalent heterocyclic groups include those obtained by removing two hydrogen atoms from the aforementioned heterocyclic compounds.

[0109] As K 1 and K 3 The phenyl, naphthyl, phenyl benzoate ester group and monovalent heterocyclic group, as well as K 2 The p-phenylene, naphthyl-1,4-diyl, 4,4'-indene, 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 that have polymerizable groups; alkenyl groups with 1 to 4 carbon atoms; alkoxy groups with 1 to 20 carbon atoms, such as methoxy, ethoxy, and butoxy; alkoxy groups with 1 to 20 carbon atoms that have polymerizable groups; fluoroalkyl groups with 1 to 4 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 with 1 or 2 alkyl groups with 1 to 6 carbon atoms, amino groups with 1 or 2 alkyl groups with 1 to 6 carbon atoms, or amino groups with 2 to 8 carbon atoms formed by the bonding of substituted alkyl groups. Unsubstituted amino groups are -NH2). etc. It should be noted that, as examples of the polymerizable groups mentioned above, (meth)acryloyl group, (meth)acryloyloxy group, etc.

[0110] In compound (I), it is preferred to be a compound represented by any one of the following formulas (I-1) to (I-8).

[0111] [Chemical Formula 8]

[0112]

[0113] [In formulas (I-1) to (I-8),

[0114] B 1~B 30 Each of the following can be represented independently: 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.

[0115] n1 to n4 represent integers from 0 to 3 independently.

[0116] When n1 is 2 or more, multiple B 2 They can be the same or different.

[0117] When n² is 2 or more, multiple B 6 They can be the same or different.

[0118] When n3 is 2 or more, multiple B 9 They can be the same or different.

[0119] When n4 is 2 or more, multiple B 14 They can be the same or different.

[0120] The preferred anthraquinone pigment is the compound represented by formula (I-9).

[0121] [Chemical Formula 9]

[0122]

[0123] In formula (I-9),

[0124] R 1 ~R 8 Each can independently represent a hydrogen atom, -R x -NH2, -NHR x -NR x 2. -SR x Or halogen atoms.

[0125] R x This refers to an alkyl group having 1 to 4 carbon atoms or an aryl group having 6 to 12 carbon atoms.

[0126] The preferred compound is the one represented by formula (I-10).

[0127] [Chemical Formula 10]

[0128]

[0129] In formula (I-10),

[0130] R 9 ~R 15 Each can independently represent a hydrogen atom, -Rx -NH2, -NHR x -NR x 2. -SR x Or halogen atoms.

[0131] R x This refers to an alkyl group having 1 to 4 carbon atoms or an aryl group having 6 to 12 carbon atoms.

[0132] The preferred acridine dye is the compound represented by formula (I-11).

[0133] [Chemical Formula 11]

[0134]

[0135] In formula (I-11),

[0136] R 16 ~R 23 Each can independently represent a hydrogen atom, -R x -NH2, -NHR x -NR x 2. -SR x Or halogen atoms.

[0137] R x This refers to an alkyl group having 1 to 4 carbon atoms or an aryl group having 6 to 12 carbon atoms.

[0138] In equations (I-9), (I-10), and (I-11), R is used as... x Alkyl groups having 1 to 6 carbon atoms include methyl, ethyl, propyl, butyl, pentyl, and hexyl, while aryl groups having 6 to 12 carbon atoms include phenyl, tolyl, xylyl, and naphthyl.

[0139] As the aforementioned anthocyanin pigments, compounds represented by formula (I-12) and compounds represented by formula (I-13) are preferred.

[0140] [Chemical Formula 12]

[0141]

[0142] In formula (I-12),

[0143] D 1 and D 2 The groups represented by any one of formulas (I-12a) to (I-12d) are independent of each other.

[0144] [Chemical Formula 13]

[0145]

[0146] n5 represents an integer from 1 to 3.

[0147] [Chemical Formula 14]

[0148]

[0149] In formula (I-13),

[0150] D 3 and D 4 The groups represented by any one of the formulas (I-13a) to (I-13h) are independently represented.

[0151] [Chemical Formula 15]

[0152]

[0153] n6 represents an integer from 1 to 3.

[0154] Dichroic pigments can be used alone or in combination. Due to their high linearity, azo pigments are suitable for fabricating anisotropic films with excellent polarization performance. From the viewpoint of polarization performance, it is preferable to include K from formula (I) above. 1 ~K 3 Any one of them is an azo dye of thiazothiazolium or benzothiazolium. When seeking polarization characteristics across the entire visible light region, it is easier to control polarization performance by combining two or more, more preferably three or more, dichroic dyes.

[0155] When multiple dichroic pigments are combined, it is preferable to include at least one dichroic pigment that has a maximum absorption wavelength in the wavelength range of 500 nm to 600 nm in the light absorption anisotropic film. When two dichroic pigments are combined, it is preferable to also include dichroic pigments with maximum absorption wavelengths in the range of 350 nm to 499 nm or 601 nm to 750 nm. When three dichroic pigments are combined, it is preferable to include dichroic pigments with maximum absorption wavelengths in the ranges of 350 nm to 499 nm, 500 nm to 600 nm, and 601 nm to 750 nm, respectively. By combining dichroic pigments in this way, the polarization function in the tilt direction can be easily improved, for example, making it a light absorption anisotropic plate suitable for use as an optical film for privacy protection.

[0156] The weight-average molecular weight of dichroic pigments is typically 300–2000, preferably 400–1000.

[0157] In one embodiment of the present invention, the dichroic pigment constituting the light-absorbing anisotropic film is preferably hydrophobic. When the dichroic pigment is hydrophobic, the compatibility between the dichroic pigment and the polymeric liquid crystal compound is improved, and the dichroic pigment and the polymeric liquid crystal compound form a uniform phase state, making it easier to obtain a light-absorbing anisotropic film with high orientation order. It should be noted that, in the present invention, the hydrophobic dichroic pigment refers to a pigment with a solubility of less than 1g in 100g of water at 25°C.

[0158] The content of the dichroic pigment in the composition for forming anisotropic light absorption films can be appropriately determined depending on the type of dichroic pigment used, and is preferably 0.1 to 50 parts by mass relative to 100 parts by mass of the polymeric liquid crystal compound, more preferably 0.1 to 30 parts by mass, further preferably 0.1 to 10 parts by mass, and particularly preferably 0.1 to 5 parts by mass. When the content of the dichroic pigment is within the above range, the orientation of the polymeric liquid crystal compound is less likely to be disturbed, and a light absorption anisotropic film with high orientation order can be obtained. It should be noted that when two or more dichroic pigments are included, the total amount of all dichroic pigments is preferably within the above range.

[0159] The composition for forming anisotropic light-absorbing films may include a polymerization initiator. The polymerization initiator is a compound capable of initiating polymerization reactions of polymerizable liquid crystal compounds, non-liquid crystal compounds containing reactive groups, etc. As a polymerization initiator, from the perspective of being able to initiate polymerization reactions at lower temperatures, a photopolymerization initiator that generates active free radicals or acids under light is preferred, and a photopolymerization initiator that generates free radicals under light is more preferred. The polymerization initiator may be used alone or in combination of two or more.

[0160] Known photopolymerization initiators can be used as photopolymerization initiators, such as self-destructive photopolymerization initiators and hydrogen-abstracting photopolymerization initiators, which generate active free radicals.

[0161] As self-destructive photopolymerization initiators, self-destructive benzoin compounds, acetophenone compounds, hydroxyacetophenone compounds, α-aminoacetophenone compounds, oxime ester compounds, acylphosphine oxide compounds, and azo compounds can be used. Additionally, as hydrogen-abstraction photopolymerization initiators, hydrogen-abstraction benzophenone compounds, benzoin ether compounds, benzoylazone compounds, dibenzocycloheptanone compounds, anthraquinone compounds, xanthonone compounds, thioxanthonone compounds, haloacetophenone compounds, dialkoxyacetophenone compounds, halodiimidazole compounds, halotriazine compounds, and triazine compounds can be used.

[0162] Iodonium salts and matte salts can be used as photopolymerization initiators that generate acids.

[0163] From the viewpoint of preventing pigment dissolution, a low-temperature reaction is preferred. From the viewpoint of reaction efficiency at low temperatures, a self-destructive photopolymerization initiator is preferred, and acetophenone compounds, hydroxyacetophenone compounds, α-aminoacetophenone compounds, and oxime ester compounds are particularly preferred.

[0164] Specifically, the following substances can be cited as photopolymerization initiators.

[0165] Benzoin compounds, including benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, and benzoin isobutyl ether;

[0166] Oligomers of 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 one and 2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propane-1-one, etc., are hydroxyacetophenone compounds;

[0167] α-aminoacetophenone compounds such as 2-methyl-2-morpholino-1-(4-methylthiophenyl)propane-1-one and 2-dimethylamino-2-benzyl-1-(4-morpholinophenyl)butane-1-one;

[0168] 1,2-Octanedione-1-[4-(phenylthio)-2-(O-benzoyl oxime)], 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazole-3-yl]-acetone-1-(O-acetyl oxime) and other oxime ester compounds;

[0169] Acylphosphine oxide compounds such as 2,4,6-trimethylbenzoyl diphenylphosphine oxide and bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide;

[0170] Benzophenone, methyl phthalobenzoate, 4-phenylbenzophenone, 4-benzoyl-4'-methyl diphenyl sulfide, 3,3',4,4'-tetra(tert-butylperoxycarbonyl)benzophenone and 2,4,6-trimethylbenzophenone and other benzophenone compounds;

[0171] Diethoxyacetophenone and other diekoxyacetophenone compounds;

[0172] 2,4-Bis(trichloromethyl)-6-(4-methoxyphenyl)-1,3,5-triazine, 2,4-bis(trichloromethyl)-6-(4-methoxynaphthyl)-1,3,5-triazine, 2,4-bis(trichloromethyl)-6-(4-methoxystyryl)-1,3,5-triazine, 2,4-bis(trichloromethyl)-6-[2-(5-methylfuran-2-yl)vinyl]-1,3,5 Triazine compounds, including 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, and 2,4-bis(trichloromethyl)-6-[2-(3,4-dimethoxyphenyl)vinyl]-1,3,5-triazine.

[0173] The photopolymerization initiator can be appropriately selected from the above-mentioned photopolymerization initiators, for example, based on its relationship with polymerizable liquid crystal compounds and non-liquid crystal compounds containing reactive groups that form light-absorbing anisotropic films.

[0174] Alternatively, commercially available photopolymerization initiators can be used. Examples of commercially available polymerization initiators include Irgacure (registered trademark) 907, 184, 651, 819, 250, 369, 379, 127, 754, OXE01, OXE02, OXE03 (manufactured by BASF); Omnirad BCIM, Esacure 1001M, Esacure KIP160 (manufactured by IDM Resins BV); SEIKUOL (registered trademark) BZ, Z, and BEE (manufactured by Seiko Chemical Co., Ltd.); kayacure (registered trademark) BP100 and VUI-6992 (manufactured by DOW Chemical Company); ADEKA OPTOMER SP-152, N-1717, N-1919, SP-170, ADEKA ARKLSNCI-831, and ADEKA ARKLS. NCI-930 (manufactured by ADEKA Co., Ltd.); TAZ-A and TAZ-PP (manufactured by Siber Hegner Co., Ltd., Japan); and TAZ-104 (manufactured by Sanwa Chemical Co., Ltd.); etc.

[0175] The content of the polymerization initiator is preferably 0.1 to 20 parts by mass relative to 100 parts by mass of the polymerizable liquid crystal compound, more preferably 0.1 to 15 parts by mass, even more preferably 0.5 to 10 parts by mass, and particularly preferably 0.5 to 8 parts by mass. When the content of the polymerization initiator is within the above range, the polymerization reaction can be carried out without significantly disturbing the orientation of the polymerizable liquid crystal compound.

[0176] Anisotropic light-absorbing films may include leveling agents. Leveling agents have the function of adjusting the flowability of the composition for forming anisotropic light-absorbing films and making the coating obtained by applying the composition smoother; specifically, surfactants are examples. As a leveling agent, at least one is preferably selected from the group consisting of leveling agents mainly composed of polyacrylate compounds and leveling agents mainly composed of compounds containing fluorine atoms. Leveling agents can be used alone or in combination of two or more.

[0177] Examples of leveling agents that are mainly composed of polyacrylate compounds include BYK-350, BYK-352, BYK-353, BYK-354, BYK-355, BYK-358N, BYK-361N, BYK-380, BYK-381 and BYK-392 (BYK Chemie).

[0178] Examples of leveling agents whose main component is a compound containing fluorine atoms include MEGAFACE (registered trademark) R-08, R-30, R-90, F-410, F-411, F-443, F-445, F-470, F-471, F-477, F-479, F-482 and F-483 (DIC Corporation); Surflon (registered trademark) S-381, S-382, S-383, S-393, SC-101, SC-105, KH-40 and SA-100 (AGC SEIMI CHEMICAL Corporation); E1830, E5844 (Daikin FineChemicals Research Institute, Ltd.); EFTOPEF301, EFTOPEF303, EFTOPEF351 and EFTOPEF352 (Mitsubishi Materials Electronic Chemicals Co., Ltd.

[0179] When the light-absorbing anisotropic film contains a leveling agent, its content is preferably 0.01 to 5 parts by mass, more preferably 0.05 to 3 parts by mass, relative to 100 parts by mass of the polymeric liquid crystal compound. When the content of the leveling agent is within the above range, it tends to facilitate the orientation of the polymeric liquid crystal compound and is less prone to unevenness, resulting in a smoother light-absorbing anisotropic film.

[0180] The light-absorbing anisotropic film may contain additives other than leveling agents. Examples of such additives include photosensitizers, antioxidants, release agents, stabilizers, colorants such as bluing agents, flame retardants, and lubricants. When other additives are included, their content is preferably more than 0% and less than 20% by mass, more preferably more than 0% and less than 10% by mass, relative to the solid composition of the light-absorbing anisotropic film forming composition.

[0181] The composition for forming anisotropic light absorption films can be manufactured using conventional methods for preparing liquid crystal compositions. Typically, it is prepared by mixing and stirring a polymerizable liquid crystal compound, a non-liquid crystal compound containing reactive groups, a dichroic pigment, and, as needed, a polymerization initiator and the aforementioned additives. Furthermore, liquid crystal compounds exhibiting smectic liquid crystal properties generally have high viscosity. Therefore, from the viewpoint of improving the coatability of the liquid crystal composition to facilitate the formation of anisotropic light absorption films, the viscosity can be adjusted by adding a solvent to the liquid crystal composition.

[0182] The solvent can be appropriately selected based on the solubility of the polymerizable liquid crystal compound, the non-liquid crystal compound containing reactive groups, and the dichroic pigment, etc. It is preferable to use a solvent that can completely dissolve the above components and is inactive to the polymerization reaction.

[0183] Examples of solvents include: methanol, ethanol, ethylene glycol, isopropanol, propylene glycol, ethylene glycol methyl ether, ethylene glycol butyl ether, and propylene glycol monomethyl ether; ester solvents such as ethyl acetate, butyl acetate, ethylene glycol methyl ether acetate, γ-butyrolactone, or propylene glycol methyl ether acetate and ethyl lactate; ketone solvents such as acetone, methyl ethyl ketone, cyclopentanone, cyclohexanone, 2-heptanone, 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; chlorine-containing solvents such as chloroform and chlorobenzene; and so on. These solvents can be used alone or in combination of two or more.

[0184] The solvent content is preferably 100 to 1900 parts by mass relative to 100 parts by mass of the solid component of the composition for forming anisotropic light absorption films, more preferably 150 to 1000 parts by mass, and even more preferably 180 to 800 parts by mass.

[0185] In this invention, the light-absorbing anisotropic film is a film formed by curing a polymeric liquid crystal compound and a dichroic pigment in a state of orientation perpendicular to the film plane. When any direction in the light-absorbing anisotropic film surface is set as the x-axis, the direction orthogonal to the x-axis in the film surface is set as the y-axis, and the film thickness direction orthogonal to the x-axis and y-axis is set as the z-axis, the following formula (1) is satisfied.

[0186] Az>(Ax+Ay) / 2 (1)

[0187] [Ax, Ay and Az are each the absorbance at the maximum absorption wavelength of the dichroic dye in the light-absorbing anisotropic film,

[0188] Ax represents the absorbance of linearly polarized light vibrating in the x-axis direction,

[0189] Ay represents the absorbance of linearly polarized light vibrating in the y-axis direction,

[0190] Az represents the absorbance of linearly polarized light vibrating in the z-axis direction.]

[0191] Ax can be measured by injecting linearly polarized light vibrating in the x-axis direction toward the film surface from the z-axis direction. Ay can be measured by injecting linearly polarized light vibrating in the y-axis direction toward the film surface from the z-axis direction. Az can be measured, for example, by vertically injecting linearly polarized light vibrating in the z-axis direction toward the side surface of the film from the x-y plane direction (that is, toward the side surface in the thickness direction when the light-absorbing anisotropic film is regarded as the x-y plane).

[0192] Regarding the absorbance in the z direction in formula (1), since light is incident from the side surface of the film, measurement may be difficult in some cases. Therefore, when the angle formed by the vibration plane of the linearly polarized light as the measurement light and the x-y plane of the film is 90°, the x-y plane of the film is inclined by 30° and 60° in the incident direction of the linearly polarized light relative to the vibration plane for measurement, so that the absorbance in the Az direction can be estimated.

[0193] Specifically, the estimation can be performed using the following method or the like.

[0194] In a state where the film is rotated by 30° and 60° with the y-axis as the rotation axis, the same linearly polarized light as the linearly polarized light for measuring Ax is injected to measure Ax(z=30) and Ax(z=60). Similarly, in a state where the film is rotated by 30° and 60° with the x-axis as the rotation axis, the same linearly polarized light as the linearly polarized light for measuring Ay is injected to measure Ay(z=30) and Ay(z=60).

[0195] At this time, if Ax(z=30)<Ax(z=60) and Ay(z=30)=Ay(z=60), then Ax(z=30)<Ax(z=60)<Ax(z=90)=Az, and if Ay(z=30)<Ay(z=60) and Ax(z=30)=Ax(z=60), then Ay(z=30)<Ay(z=60)<Ay(z=90)=Az, so it can be said that formula (1) is necessarily satisfied.

[0196] Especially when there is no absorption anisotropy in the x-y plane, that is, when Ax and Ay are equal, since Ax(z=30)=Ay(z=30) and Ax(z=60)=Ay(z=60), it is possible to set Ax(z=30) and Ay(z=30) as A(z=30), and set Ax(z=60) and Ay(z=60) as A(z=60). That is, if A(z=30)<A(z=60), the relationship of A(z=30)<A(z=60)<A(z=90)=Az is satisfied. Furthermore, if A(z=30)>(Ax+Ay) / 2, it can be said that Az necessarily satisfies formula (1).

[0197] In addition, in the present invention, it is preferable that the light-absorbing anisotropic film satisfies the following formulas (2) and (3) in addition to satisfying the above formula (1).

[0198] Ax(z=60) / Ax>5 (2)

[0199] Ay(z=60) / Ay>5 (3)

[0200] [Ax, Ay and Az have the same meanings as described above. Both Ax(z=60) and Ay(z=60) are the absorbances at the maximum absorption wavelength of the dichroic dye in the light-absorbing anisotropic film,

[0201] Ax(z=60) represents the absorbance of linearly polarized light vibrating in the x-axis direction when the film is rotated by 60° around the y-axis as the rotation axis,

[0202] Ay(z=60) represents the absorbance of linearly polarized light vibrating in the y-axis direction when the film is rotated by 60° around the x-axis as the rotation axis.]

[0203] Ax(z=60) can be measured by irradiating the same linearly polarized light as the linearly polarized light used for measuring Ax in a state where the film is rotated by 60° around the y-axis as the rotation axis. Here, the rotation of the film is performed by rotating the film in the state where Ax was measured by 60° around the y-axis as the rotation axis toward the incident direction of the linearly polarized light. Ay(z=60) can be measured by irradiating the same linearly polarized light as the linearly polarized light used for measuring Ay in a state where the film is rotated by 60° around the x-axis as the rotation axis. Here, the rotation of the film is performed by rotating the film in the state where Ay was measured by 60° around the x-axis as the rotation axis toward the incident direction of the linearly polarized light.

[0204] Regarding Ax(z=60) / Ax and Ay(z=60) / Ay, a larger value thereof means that more excellent light absorption anisotropy is exhibited. Their values can be, for example, 50 or less, and can also be 30 or less.

[0205] Furthermore, in this invention, a light-absorbing anisotropic film is more preferably satisfied with the following formulas (4) and (5).

[0206] Ax(z=60) / Ax>10 (4)

[0207] Ay(z=60) / Ay>10 (5)

[0208] By using compounds that form smectic liquid crystal phases, especially higher-order smectic liquid crystal phases, as polymerizable liquid crystal compounds, it is easy to obtain light absorption anisotropic films that also satisfy the above formulas (2) and (3), or formulas (4) and (5).

[0209] When an anisotropic light absorption film satisfies equations (1), (2), and (3), it can be said to have excellent anisotropic light absorption, i.e., excellent polarization performance. Through this excellent characteristic, it can effectively transmit light from the front direction and effectively absorb light from the tilted direction.

[0210] The thickness of the light-absorbing anisotropic film is preferably 0.01 μm or more, more preferably 0.05 μm or more, even more preferably 0.1 μm or more, preferably less than 2 μm, more preferably 1.5 μm or less, and even more preferably 1 μm or less. When the thickness of the light-absorbing anisotropic film is above the above lower limit, the light absorption from the tilt direction becomes good, and the polarization characteristics in the tilt direction are easily improved. When the thickness is below the above upper limit, the orientation of the polymerizable liquid crystal compound and the dichroic pigment is not easily disturbed, and high transmittance in the front direction can be ensured, which can be expected to achieve thinness when assembled into display devices, etc. The thickness of the light-absorbing anisotropic film can be measured using a laser microscope, film thickness gauge, etc., and the thickness of each layer of the film substrate constituting the light-absorbing anisotropic plate is also measured in the same way.

[0211] In this invention, the light-absorbing anisotropic film is preferably a liquid crystal curable film with a high degree of orientation order. With respect to liquid crystal curable films with a high degree of orientation order, Bragg peaks from higher-order structures such as hexagonal phases and crystalline phases can be obtained in X-ray diffraction measurements. A Bragg peak refers to a peak originating from a planar periodic structure of molecular orientation. Therefore, the light-absorbing anisotropic film constituting the light-absorbing anisotropic plate of this invention preferably exhibits a Bragg peak in X-ray diffraction measurements. That is, in the light-absorbing anisotropic film constituting the light-absorbing anisotropic plate of this invention, the polymerizable liquid crystal compound or its polymer is preferably oriented in such a way that the film exhibits a Bragg peak in X-ray diffraction measurements. In this invention, the planar periodic interval of molecular orientation is preferably [missing information]. The light absorption anisotropic film exhibits a high degree of orientational order, such as the Bragg peak. This can be achieved by controlling the type of polymerizable liquid crystal compound used, the type or amount of dichroic pigment, and the type or amount of polymerization initiator.

[0212] <Membrane Substrate>

[0213] Anisotropic light-absorbing films can be formed by coating a light-absorbing anisotropic film forming composition containing a polymeric liquid crystal compound, a non-liquid crystal compound containing reactive groups, and a dichroic pigment onto a film substrate.

[0214] As the substrate film, resin film substrates conventionally known in the field of optical films can be used. When assembling the light-absorbing anisotropic plate of the present invention to other optical laminates, display devices, etc., and transferring the film substrate without peeling it off, a transparent resin film substrate is preferred. A transparent resin film substrate refers to a film substrate that has the property of transmitting light, especially visible light. Transmittance refers to the characteristic that the visibility-corrected transmittance of light in the wavelength range of 380 nm to 780 nm is 80% or more.

[0215] Examples of resins constituting the membrane substrate include: polyolefin resins such as polyethylene and polypropylene; cyclic olefin resins such as norbornene polymers; polyester resins such as polyethylene terephthalate and polyethylene naphthalate; poly(meth)acrylic acid and poly(meth)acrylate resins such as methyl methacrylate; cellulose ester resins such as cellulose triacetate, cellulose diacetate, and cellulose acetate propionate; vinyl alcohol resins such as polyvinyl alcohol and polyvinyl acetate; polycarbonate resins; polystyrene resins; polyaryl ester resins; polysulfone resins; polyethersulfone resins; polyamide resins; polyimide resins; polyetherketone resins; polyphenylene sulfide resins; polyphenylene ether resins; and mixtures thereof; etc. From the viewpoints of versatility and heat resistance, at least one resin selected from the group consisting of polyimide resins, cellulose ester resins, cyclic olefin resins, polyester resins, and poly(meth)acrylic acid resins is preferred, and cellulose ester resins and cyclic olefin resins are more preferred. These can be used alone or in combination of two or more. Such resins can be made into films using known methods such as solvent casting and melt extrusion, and used as resin film substrates.

[0216] Commercially available products can be used as membrane substrates or resins constituting membrane substrates. Examples of commercially available cellulose ester resin membrane substrates include Fujitack Film (manufactured by Fuji Photo Film Co., Ltd.); KC8UX2M, KC8UY, and KC4UY (all manufactured by KONICA MINOLTA OPTO, INC.). 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.). Such cyclic olefin resins can be used to form membranes as membrane substrates using known methods such as solvent casting and melt extrusion. Examples of commercially available cyclic olefin resin base materials include Escena (registered trademark), SCA40 (registered trademark) (both manufactured by Sekisui Chemicals Co., Ltd.), ZEONORFILM (registered trademark) (manufactured by OPTES Co., Ltd.), and ARTONFILM (registered trademark) (manufactured by JSR Co., Ltd.).

[0217] Surface treatment can be performed on the membrane substrate. Examples of surface treatment methods include: treating the surface of the membrane substrate using corona or plasma under a vacuum to atmospheric pressure atmosphere; laser treatment of the membrane substrate surface; ozone treatment of the membrane substrate surface; saponification treatment of the membrane substrate surface; flame treatment of the membrane substrate surface; coating the membrane substrate surface with a coupling agent; primer treatment of the membrane substrate surface; and graft polymerization, in which reactive monomers or reactive polymers are attached to the membrane substrate surface and then irradiated with radiation, plasma, or ultraviolet light to cause a reaction; etc. Among these, the method of treating the membrane substrate surface with corona or plasma under a vacuum to atmospheric pressure atmosphere is preferred.

[0218] Examples of methods for surface treatment of membrane substrates using corona discharge or plasma include: placing the membrane substrate between opposing electrodes at a pressure near atmospheric pressure, generating corona discharge or plasma to perform surface treatment of the membrane substrate; flowing gas into the space between opposing electrodes, plasmaizing the gas between the electrodes, and blowing the plasmaized gas onto the membrane substrate; and generating glow discharge plasma under low pressure conditions to perform surface treatment of the membrane substrate; and so on.

[0219] Preferably, the following methods are used: a method of surface treatment of the membrane substrate by placing a membrane substrate between opposing electrodes at a pressure near atmospheric pressure and generating corona or plasma; or a method of flowing gas into the space between opposing electrodes, plasmaizing the gas between the electrodes, and blowing the plasmaized gas onto the membrane substrate. The above-mentioned corona or plasma-based surface treatments are typically performed using commercially available surface treatment equipment.

[0220] The membrane substrate may have a protective film on the side opposite to the side on which the light-absorbing anisotropic film-forming composition is coated. Examples of protective films include films made of polyethylene, polyethylene terephthalate, polycarbonate, and polyolefins, as well as films that also include an adhesive layer. Polyethylene terephthalate is preferred because it exhibits minimal thermal deformation during drying. By having a protective film on the side opposite to the side on which the light-absorbing anisotropic film-forming composition is coated, film swaying during substrate handling and slight vibrations of the coating surface can be suppressed, thereby improving the uniformity of the coating.

[0221] From a practical point of view, a thinner membrane substrate is preferred, but from a strength and processability point of view, a thicker substrate is preferred. In one embodiment of the present invention, the thickness of the membrane substrate is preferably 5 μm to 300 μm, more preferably 20 μm to 200 μm.

[0222] <Method for fabricating anisotropic light-absorbing plates>

[0223] In this invention, the light-absorbing anisotropic film is obtained by aligning the absorption axis of the dichroic pigment along a direction orthogonal to the film surface. The direction of the absorption axis of the dichroic pigment in such a host-guest type light-absorbing anisotropic film is typically controlled by the orientation of the polymerizable liquid crystal compound.

[0224] By aligning the long axis of the polymeric liquid crystal compound to a direction orthogonal to the film surface, the absorption axis of the dichroic pigment can typically be aligned in a direction orthogonal to the film surface. The orientation direction of the polymeric liquid crystal compound can be controlled by the properties of the substrate coated with the liquid crystal composition (which includes the polymeric liquid crystal compound, a non-liquid crystal compound containing reactive groups, and a dichroic pigment), the orientation film, and the properties of the polymeric liquid crystal compound.

[0225] In this invention, the light-absorbing anisotropic plate can be manufactured, for example, by a method including the following steps:

[0226] A process of forming a coating film on a film substrate, with or without an orientation film, of a liquid crystal composition (composition for forming anisotropic light absorption film) comprising a polymeric liquid crystal compound, a non-liquid crystal compound containing reactive groups, and a dichroic pigment.

[0227] The process of drying the resulting coating to obtain a dried coating; and,

[0228] A process for curing the polymeric liquid crystal compound and dichroic pigment in the above coating film in a state of orientation perpendicular to the plane of the above coating film.

[0229] In this invention, a light-absorbing anisotropic film can be formed on an alignment film. The alignment film has an orientation control force that allows the polymeric liquid crystal compound to be aligned in a desired direction. By coating the light-absorbing anisotropic film forming composition onto the alignment film, a light-absorbing anisotropic film with good alignment precision can be easily obtained. Preferably, the alignment film has solvent resistance that prevents dissolution due to coating of the aforementioned light-absorbing anisotropic film forming composition, and also has heat resistance during heat treatment for removing solvents and aligning the polymeric liquid crystal compound. Examples of such alignment films include alignment films containing an oriented polymer and photo-alignment films; specifically, for example, the alignment film containing an oriented polymer and photo-alignment film described in Japanese Patent Application Publication No. 2016-27387 can be used. In one embodiment of this invention, a film substrate and a light-absorbing anisotropic film are laminated adjacent to each other.

[0230] As a method for coating a light-absorbing anisotropic film-forming composition onto a film substrate or the like, known methods include, for example, spin coating, extrusion, gravure coating, die coating, bar coating, applicator coating, and printing methods such as stencil coating.

[0231] When the composition for forming anisotropic light absorption films contains a solvent, the solvent is typically removed from the coated composition. Methods for solvent removal include natural drying, ventilation drying, heating drying, and reduced pressure drying. The coating is preferably dried such that the residual solvent in the anisotropic light absorption film is less than 1% by weight relative to the total mass of the anisotropic light absorption film. The amount of residual solvent can be quantified by peeling the anisotropic light absorption film from the film substrate and weighing it, immersing the resulting anisotropic light absorption film in a solvent such as tetrahydrofuran that dissolves the anisotropic light absorption film, irradiating it with ultrasound for 10 minutes to extract the dissolved components, and then analyzing the solution using gas chromatography. Drying conditions such as drying temperature and drying time can be appropriately determined based on the composition of the composition for forming anisotropic light absorption films and the material of the film substrate.

[0232] The polymeric liquid crystal compound in the coating is usually heated to a temperature above the point where it transforms into a liquid crystal state or solution state, and then cooled to a temperature for liquid crystal orientation, thereby aligning together with the dichroic pigment to form a liquid crystal phase.

[0233] Regarding the temperature for aligning the polymeric liquid crystal compound in the coating film, it can be determined in advance by observing the texture of the composition containing the polymeric liquid crystal compound. Furthermore, solvent removal and liquid crystal alignment can be performed simultaneously. The temperature at this time, while depending on the solvent to be removed and the type of polymeric liquid crystal compound used, is preferably in the range of 50 to 200°C, and more preferably in the range of 80 to 130°C.

[0234] By polymerizing and curing a polymeric liquid crystal compound while maintaining its liquid crystal state, a light-absorbing anisotropic film is formed in the form of a cured film of a liquid crystal composition. Photopolymerization is preferred as the polymerization method. The light irradiating the dried coating film during photopolymerization can be appropriately selected based on the types of polymeric liquid crystal compounds and non-liquid crystal compounds containing reactive groups contained in the dried coating film (especially the types of polymeric groups possessed by the polymeric liquid crystal compound / non-liquid crystal compound containing reactive groups), the type of polymerization initiator, and their amounts. For a liquid crystal cured film containing a polymeric liquid crystal compound polymerized while maintaining a smectic liquid crystal phase, it exhibits higher polarization performance compared to conventional host-guest type liquid crystal cured films (i.e., liquid crystal cured films obtained by polymerizing a polymeric liquid crystal compound while maintaining a nematic liquid crystal phase). Furthermore, it demonstrates superior polarization performance and film strength compared to cases where only dichroic pigments or lyotropic liquid crystals are coated.

[0235] Examples of light sources for 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 lights, microwave-excited mercury lamps, and metal halide lamps. Light sources with a luminous emission distribution below 400 nm, such as low-pressure mercury lamps, medium-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, chemical lamps, black lights, microwave-excited mercury lamps, and metal halide lamps, are preferred. Ultraviolet light parallel to the normal direction of the film substrate is even more preferred.

[0236] The irradiation energy of the active energy rays is preferably set at an intensity of 10–5000 mJ / cm in the wavelength range effective for activating the polymerization initiator. 2 The setting method is preferred, and more preferably 100–2000 mJ / cm. 2 .

[0237] The light-absorbing anisotropic plate of the present invention can be a long strip of film and can be manufactured continuously in a roll-to-roll manner. Examples of manufacturing methods include those comprising the following steps:

[0238] The process of unwinding a long strip of film substrate wound into a roll and forming a coating film on the film substrate with or without an orientation film, comprising a liquid crystal composition containing a polymeric liquid crystal compound, a non-liquid crystal compound containing reactive groups, and a dichroic pigment.

[0239] A process of continuously drying the resulting coating film to obtain a dried coating film; and,

[0240] A process in which the polymeric liquid crystal compound and dichroic pigment in the above coating are oriented in a direction perpendicular to the plane of the coating and continuously irradiated with active energy rays, thereby curing the coating.

[0241] Examples of methods for unwinding a long strip of film substrate wound into a roll include: a method that involves providing a suitable rotating mechanism in a core on which the film substrate is wound, and using the rotating mechanism to rotate the roll formed by the film substrate; a method that involves providing a suitable auxiliary roller along the direction in which the film substrate is transported from the roll, and using the rotating mechanism of the auxiliary roller to unwind the film substrate; and so on. Preferably, the film substrate is unwound while applying appropriate tension to the film substrate.

[0242] The dimensions of the elongated membrane substrate can be appropriately determined. The length of the long side of the membrane substrate is, for example, 10 to 3000 m, preferably 100 to 2000 m. In addition, the length of the short side of the membrane substrate is, for example, 0.1 to 5 m, preferably 0.2 to 2 m.

[0243] Regarding the film substrate that is unwound from the film substrate, a light-absorbing anisotropic film-forming composition is coated on its surface as it passes through the coating apparatus using a suitable coating apparatus. Gravure coating, die coating, and stencil coating are preferred as coating apparatuses for continuously coating the light-absorbing anisotropic film-forming composition.

[0244] The film substrate, which has passed through the coating apparatus, is transferred to a drying oven and dried thereon, thereby continuously forming a dried coating film of the light-absorbing anisotropic film-forming composition on the surface of the film substrate. For example, a hot air drying oven combining ventilation drying and heating drying methods can be used as the drying oven.

[0245] The solvent is removed from the composition for forming anisotropic light-absorbing films by passing through a drying oven, and the polymerizable liquid crystal compound contained in the composition is oriented by heat. The drying oven can be composed of multiple zones with different set temperatures, or multiple drying ovens with different set temperatures can be arranged in series.

[0246] Next, while the polymerizable liquid crystal compound in the coating film remains in an oriented state, the coating film is conveyed to an active energy ray irradiation apparatus. In the active energy ray irradiation apparatus, active energy rays are applied, whereby the polymerizable liquid crystal compound is polymerized in the oriented state, and a light-absorbing anisotropic film is continuously obtained.

[0247] By winding the continuously manufactured light-absorbing anisotropic plate around a second winding core, the light-absorbing anisotropic plate wound into a roll form can be obtained. It should be noted that during winding, co-winding (Japanese: 供巻き) using a suitable spacer may also be performed.

[0248] The light-absorbing anisotropic plate of the present invention has an excellent balance between moderate film strength and the orientation order of the polymerizable liquid crystal compound, exhibits high film strength and flexibility, and also exhibits a polarizing function in the oblique direction, and thus can be suitably used as a constituent material for liquid crystal display devices, organic electroluminescent (EL) display devices and the like. Therefore, the present invention is also directed to a display material containing the light-absorbing anisotropic plate of the present invention, and a display device containing the light-absorbing anisotropic plate of the present invention.

[0249] The light-absorbing anisotropic plate of the present invention can be used, for example, as a peep-preventing film and a material for improving the appearance of a display. In addition, since the light-absorbing anisotropic plate of the present invention has excellent polarizing performance and also excellent flexibility, it is also suitable as a flexible display material.

[0250] When assembled into a display device as a display material, specifically, for example, it may be bonded via a pressure-sensitive adhesive layer to the viewing side of a circularly polarizing plate including a polarizing film having a polarizing function and having an absorption axis in a direction parallel to the film surface, a retardation film, and the like.

[0251] Examples of the display device include liquid crystal display devices, organic electroluminescent (EL) display devices, inorganic electroluminescent (EL) display devices, touch panel display devices, electron emission display devices (for example, field emission display devices (FED), surface-conduction electron-emitter display devices (SED)), electronic paper (display devices using electronic ink or electrophoretic elements), plasma display devices, projection display devices (for example, grating light valve (GLV) display devices, display devices having a digital micromirror device (DMD)), piezoelectric ceramic displays and the like, each of which has a display element and contains a light-emitting element or a light-emitting device as a light-emitting source.

[0252] Each material and component constituting the display device, such as a polarizing film having a polarizing function and having an absorption axis in a direction parallel to the film surface, a retardation film and the like, can be appropriately selected and used from known materials and components used in display devices.

[0253] Examples

[0254] The present invention will now be described in more detail using examples and comparative examples. Unless otherwise specified, “%” and “parts” in the examples and comparative examples refer to “mass %” and “mass parts”, respectively.

[0255] 1. Example 1

[0256] (1) Preparation of compositions for forming anisotropic light-absorbing films

[0257] The following components were mixed and stirred at 80°C for 1 hour to obtain a composition for forming anisotropic light-absorbing films. The dichroic pigment used was the azo pigment described in the examples of Japanese Patent Application Publication No. 2013-101328.

[0258] 75 parts of the polymeric liquid crystal compound represented by formula (A-6)

[0259] [Chemical Formula 16]

[0260]

[0261] • 25 parts of the polymeric liquid crystal compound represented by formula (A-7)

[0262] [Chemical Formula 17]

[0263]

[0264] • One part of the dichroic pigment (1) shown below

[0265] [Chemical Formula 18]

[0266]

[0267] • Polymerization initiator: 6 parts of 2-dimethylamino-2-benzyl-1-(4-morpholinophenyl)-1-butanone (Irgacure 369; manufactured by Ciba Specialty Chemicals).

[0268] • Non-liquid crystal compounds containing reactive groups (1): 1.5 parts of dipentaerythritol hexaacrylate (6-functional)

[0269] Solvent: 650 parts o-xylene

[0270] (2) Fabrication of light-absorbing anisotropic films

[0271] A cellulose triacetate membrane (KONICA MINOLTA KC4UY-TAC, 40 μm thick) used as the membrane substrate was cut into quadrilaterals and subjected to one corona treatment 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. A light-absorbing anisotropic film-forming composition was then coated onto the corona-treated surface of the membrane substrate using a bar coater, and subsequently dried in a drying oven set to 100°C for 1 minute.

[0272] Next, a high-pressure mercury lamp (Unicure VB-15201BY-A, manufactured by Ushio Electric Co., Ltd.) was used to irradiate the area with ultraviolet light (under a nitrogen atmosphere, wavelength: 365nm, cumulative light intensity at 365nm: 1000mJ / cm²). 2 Thus, a light-absorbing anisotropic film with polymerizable liquid crystal compound and dichroic pigment perpendicularly oriented to the coating plane is formed, resulting in a light-absorbing anisotropic plate (1) formed from the film substrate / light-absorbing anisotropic film. At this time, the thickness of the light-absorbing anisotropic film is measured using an ellipsometer, and the result is 0.4 μm.

[0273] (3) Characteristic Evaluation

[0274] [Evaluation of membrane strength]

[0275] An adhesive was laminated onto the anisotropic light-absorbing membrane side of the obtained anisotropic light-absorbing plate (1), and a cellulose triacetate membrane was bonded onto the adhesive layer. For the laminate formed by the membrane substrate, the anisotropic light-absorbing membrane, the adhesive layer, and the cellulose triacetate membrane obtained by this bonding, a notch was introduced at the interface between the anisotropic light-absorbing membrane and the adhesive layer, and then the anisotropic light-absorbing plate (1) was peeled off at a peeling speed of 100 mm / min. The results are shown in Table 2.

[0276] <Evaluation Criteria>

[0277] A: The light-absorbing anisotropic plate peels off at the interface with the adhesive (without material damage).

[0278] B: Less than 1 / 3 of the peeling surface of the light-absorbing anisotropic plate experiences material failure.

[0279] C: Material failure occurs at more than 1 / 3 of the peeling surface of the light-absorbing anisotropic plate.

[0280] D: Material failure occurs across the entire surface of the anisotropic light-absorbing plate.

[0281] [Evaluation of flexibility]

[0282] For the obtained light absorption anisotropic plate (1), the bending resistance was evaluated in the following manner using the general test method for coatings - bending resistance (cylindrical core) as described in JIS-K-5600-5-1.

[0283] The light-absorbing anisotropic plate (1) was cut into 25mm × 200mm squares. A cylindrical core bending resistance testing machine (Type II, manufactured by TP Giken Co., Ltd.) was used. Under conditions of 25°C and 55% RH, the light-absorbing anisotropic film was wound around a mandrel with a diameter of 6mm (bending radius R = 3mm) as the outer side, and a bending test was conducted. In a dark room environment, the light-absorbing anisotropic plates were visually inspected after 10,000 bends, 50,000 bends, and 100,000 bends using transmitted light. The results are shown in Table 2.

[0284] <Evaluation Criteria>

[0285] A: There was no change before and after the experiment.

[0286] B: Delamination confirmed after 100,000 bending cycles.

[0287] C: Delamination confirmed after 50,000 bends.

[0288] D: Delamination confirmed after 10,000 bending cycles.

[0289] E: Substrate failure was confirmed after just one bending.

[0290] [Front-facing / Oblique-facing Absorbance Ratio]

[0291] The absorbance of the light-absorbing anisotropic plate (1) was measured in the following manner.

[0292] Using a spectrophotometer (Shimadzu Corporation UV-3150) with a folding device incorporating a prism polarizer, the three-dimensional absorbance at wavelengths exhibiting maximum absorption is measured in 2 nm increments within the 380–680 nm wavelength range using the two-beam method. Here, three-dimensional absorbance refers to the absorbance (Ax, Ay, Az) relative to linearly polarized light in each direction, with any direction within the anisotropic light absorption film defined as the x-axis, the direction orthogonal to the x-axis as the y-axis, and the film thickness direction as the z-axis. Specifically, the measurement is performed by rotating the sample relative to the linearly polarized light used as the measurement beam.

[0293] Furthermore, the absorbance in the z-direction is defined as light incident from the side of the sample, making it difficult to measure. Therefore, the absorbance in the Az-direction is estimated by measuring the sample with its xy plane tilted at 60° relative to the vibration plane of the linearly polarized light used for measurement.

[0294] Specifically, with the sample rotated 30° and 60° including the y-axis, the same linearly polarized light as that used when measuring Ax was incident, and Ax (z = 60) was measured. Similarly, with the sample rotated 60° including the x-axis, the same linearly polarized light as that used when measuring Ay was incident, and Ay (z = 60) was measured.

[0295] It should be noted that when the xy plane does not exhibit anisotropic absorption, i.e., when Ax and Ay are equal, since Ax(z=60) = Ay(z=60), Ax(z=60) and Ay(z=60) can be taken as A(z=60). The value of Ax(z=60) / Ax is used as the front / oblique absorbance ratio.

[0296] 2. Examples 2-5

[0297] In the composition for forming anisotropic light-absorbing films, the amount of the non-liquid crystal compound containing reactive groups was changed to the amount shown in Table 1. Otherwise, the anisotropic light-absorbing plates (2) to (5) were prepared in the same manner as in Example 1, and the characteristics were evaluated in the same manner as in Example 1. The results are shown in Table 2.

[0298] 3. Example 6

[0299] In the composition for forming anisotropic light-absorbing films, a dichroic pigment (2) as shown below was used instead of a dichroic pigment (1). Otherwise, an anisotropic light-absorbing plate (6) was prepared in the same manner as in Example 2, and its characteristics were evaluated in the same manner as in Example 1. The results are shown in Table 2.

[0300] [Chemical Formula 19]

[0301]

[0302] 4. Example 7

[0303] In the composition for forming anisotropic light-absorbing films, a dichroic pigment (3) as shown below was used instead of a dichroic pigment (1). Otherwise, an anisotropic light-absorbing plate (7) was prepared in the same manner as in Example 2, and its properties were evaluated in the same manner as in Example 1. The results are shown in Table 2.

[0304] [Chemical Formula 20]

[0305]

[0306] 5. Example 8

[0307] In the composition for forming anisotropic light-absorbing films, one part by mass of each of dichroic pigments (1), (2) and (3) were used as dichroic pigments. Otherwise, anisotropic light-absorbing plates (8) were prepared in the same manner as in Example 2, and their properties were evaluated in the same manner as in Example 1. The results are shown in Table 2.

[0308] 6. Examples 9-17

[0309] In the composition for forming anisotropic light absorption films, the non-liquid crystal compound (1) containing reactive groups was replaced with the non-liquid crystal compounds (2) to (10) containing reactive groups shown in Table 1. Otherwise, the anisotropic light absorption plates (9) to (17) were prepared in the same manner as in Example 2, and the characteristics were evaluated in the same manner as in Example 1. The results are shown in Table 2.

[0310] It should be noted that the following compounds are used as the non-liquid crystal compounds (2) to (10) containing reactive groups shown in Table 1.

[0311] • Non-liquid crystal compounds containing reactive groups (2): Tricyclodecanediethanol diacrylate (2-functional)

[0312] • Non-liquid crystal compounds containing reactive groups (3): bis(trimethylolpropane)tetraacrylate (4-functional)

[0313] • Non-liquid crystal compounds containing reactive groups (4): Ethoxylated pentaerythritol polyacrylate (6-functional)

[0314] • Non-liquid crystal compounds containing reactive groups (5): Tripentaerythritol octaacrylate (8-functional)

[0315] • Non-liquid crystal compounds containing reactive groups (6): Trimethylolpropane trimethacrylate (3-functional)

[0316] • Non-liquid crystal compounds containing reactive groups (7): Pentaerythritol tetra(3-mercaptopropionate) (4-functional)

[0317] • Non-liquid crystal compounds containing reactive groups (8): Dipentaerythritol hexa(3-mercaptopropionate) (6-functional)

[0318] • Non-liquid crystal compounds containing reactive groups (9): 3,4-epoxycyclohexanecarboxylic acid-3',4'-epoxycyclohexylmethyl ester (2-functional)

[0319] • Non-liquid crystal compounds containing reactive groups (10): Ethyl isocyanate acrylate (Japanese: 2-イソシアナトエチルアクリラート)(2-functional)

[0320] 7. Example 18

[0321] In the composition for forming anisotropic light-absorbing films, 0.3 parts by weight of a polyacrylate compound (BYK-361N; manufactured by BYK-Chemie) was added as a leveling agent. The amount of dichroic pigment (1) was changed to 2.8 parts by weight and the amount of solvent was changed to 250 parts by weight. Otherwise, an anisotropic light-absorbing plate (18) was prepared in the same manner as in Example 2, and its properties were evaluated in the same manner as in Example 1. The results are shown in Table 2.

[0322] 8. Example 19

[0323] As the membrane substrate, a membrane with a 3 μm thick hard coating (a layer composed of acrylic resin) formed on a 40 μm cyclic olefin polymer membrane was used. Otherwise, a light-absorbing anisotropic plate (19) was fabricated in the same manner as in Example 2, and its properties were evaluated in the same manner as in Example 1. The results are shown in Table 2.

[0324] 9. Comparative Example 1

[0325] A glass plate (0.7 mm thick) was used instead of a film substrate. No non-liquid crystal compound containing reactive groups was incorporated into the composition for forming the anisotropic light-absorbing film. Otherwise, the anisotropic light-absorbing plate (20) was prepared in the same manner as in Example 18, and its properties were evaluated in the same manner as in Example 1. The results are shown in Table 2.

[0326] 10. Comparative Example 2

[0327] The light-absorbing anisotropic film was prepared in the same manner as in Example 1, except that a non-liquid crystal compound containing reactive groups was not incorporated into the composition for forming the light-absorbing anisotropic film. The characteristics were evaluated in the same manner as in Example 1. The results are shown in Table 2.

[0328] 11. Comparative Example 3

[0329] The light-absorbing anisotropic film formation composition did not incorporate a non-liquid crystal compound containing reactive groups. Otherwise, the light-absorbing anisotropic plate (22) was prepared in the same manner as in Example 19, and its characteristics were evaluated in the same manner as in Example 1. The results are shown in Table 2.

[0330] [Table 1]

[0331]

[0332] [Table 2]

[0333]

Claims

1. Anisotropic light-absorbing plate, comprising a film substrate and anisotropic light-absorbing film. The light-absorbing anisotropic film is a cured film comprising a liquid crystal composition containing a polymeric liquid crystal compound, a non-liquid crystal compound containing reactive groups, and a dichroic pigment. Furthermore, the polymeric liquid crystal compound and the dichroic pigment are cured in a state where they are oriented perpendicular to the plane of the light-absorbing anisotropic film. The non-liquid crystal compound containing reactive groups comprises a polyfunctional (meth)acrylate having 5 or 6 reactive groups within the molecule. When any direction within the anisotropic light absorption film is defined as the x-axis, the direction orthogonal to the x-axis within the film surface is defined as the y-axis, and the film thickness direction orthogonal to both the x-axis and y-axis is defined as the z-axis, the light absorbance of the film satisfies the following equations (4) and (5): Ax(z=60) / Ax>10 (4) Ay(z=60) / Ay>10 (5) In equations (4) and (5), Ax, Ay, Ax(z=60), and Ay(z=60) are all absorbance at the maximum absorption wavelength of the dichroic pigment in the anisotropic light absorption film. Ax represents the absorbance of linearly polarized light vibrating along the x-axis. Ay represents the absorbance of linearly polarized light vibrating along the y-axis. Ax (z = 60) represents the absorbance of linearly polarized light vibrating along the x-axis when the membrane is rotated 60° about the y-axis. Ay (z = 60) represents the absorbance of linearly polarized light vibrating along the y-axis when the film is rotated 60° about the x-axis. The polymerizable liquid crystal compound is a liquid crystal compound exhibiting a smectic liquid crystal phase.

2. The light-absorbing anisotropic plate as described in claim 1, wherein, Non-liquid crystal compounds containing reactive groups have the same reactive groups as polymeric liquid crystal compounds.

3. The light-absorbing anisotropic plate as described in claim 1 or 2, wherein, The content of the non-liquid crystal compound containing reactive groups is 0.2 parts by mass or more and 15 parts by mass or less, relative to 100 parts by mass of the polymerizable liquid crystal compound.

4. The light-absorbing anisotropic plate according to any one of claims 1 to 3, wherein, Dichroic pigments are azo pigments.

5. The light-absorbing anisotropic plate according to any one of claims 1 to 4, wherein, The thickness of the light-absorbing anisotropic film is less than 2 μm.

6. The light-absorbing anisotropic plate according to any one of claims 1 to 5, wherein, The light-absorbing anisotropic film showed a Bragg peak in X-ray diffraction measurements.

7. The light-absorbing anisotropic plate according to any one of claims 1 to 6, wherein, The membrane substrate is a resin membrane composed of at least one selected from the group consisting of polyimide resins, cellulose ester resins, cyclic olefin resins, polyester resins and poly(meth)acrylic resins.

8. The light-absorbing anisotropic plate according to any one of claims 1 to 7, wherein, The membrane substrate is adjacent to the light-absorbing anisotropic membrane.

9. A method for manufacturing a light-absorbing anisotropic plate, wherein the light-absorbing anisotropic plate comprises a film substrate and a light-absorbing anisotropic film, the manufacturing method comprising the following steps: A process of forming a coating film on a film substrate comprising a polymeric liquid crystal compound, a non-liquid crystal compound containing reactive groups, and a dichroic pigment; The process of drying the resulting coating to obtain a dried coating; and, A process of curing the polymeric liquid crystal compound and dichroic pigment in the coating film in a state of orientation perpendicular to the plane of the coating film. The non-liquid crystal compound containing reactive groups comprises a polyfunctional (meth)acrylate having 5 or 6 reactive groups within the molecule. When any direction within the anisotropic light absorption film is defined as the x-axis, the direction orthogonal to the x-axis within the film surface is defined as the y-axis, and the film thickness direction orthogonal to both the x-axis and y-axis is defined as the z-axis, the light absorbance of the film satisfies the following equations (4) and (5): Ax(z=60) / Ax>10 (4) Ay(z=60) / Ay>10 (5) In equations (4) and (5), Ax, Ay, Ax(z=60), and Ay(z=60) are all absorbance at the maximum absorption wavelength of the dichroic pigment in the anisotropic light absorption film. Ax represents the absorbance of linearly polarized light vibrating along the x-axis. Ay represents the absorbance of linearly polarized light vibrating along the y-axis. Ax (z = 60) represents the absorbance of linearly polarized light vibrating along the x-axis when the membrane is rotated 60° about the y-axis. Ay (z = 60) represents the absorbance of linearly polarized light vibrating along the y-axis when the film is rotated 60° about the x-axis. The polymerizable liquid crystal compound is a liquid crystal compound exhibiting a smectic liquid crystal phase.

10. The manufacturing method as described in claim 9, wherein, The light-absorbing anisotropic plate is elongated, and the manufacturing method includes the following steps: The process of unwinding a long strip of film substrate that is wound into a roll and forming a coating film on the film substrate that comprises a polymeric liquid crystal compound, a non-liquid crystal compound containing reactive groups and a dichroic pigment. A process of continuously drying the resulting coating film to obtain a dried coating film; and, A process in which polymeric liquid crystal compounds and dichroic pigments in a dried coating are oriented perpendicularly to the plane of the coating and continuously irradiated with active energy rays, thereby curing the coating.

11. A display material comprising the light-absorbing anisotropic plate according to any one of claims 1 to 8.

12. A display device comprising a light-absorbing anisotropic plate according to any one of claims 1 to 8.

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