Polymerizable liquid crystal composition

Abstract

A polymeric liquid crystal composition comprising a polymeric liquid crystal compound, a dichroic dye, and a photopolymerization initiator, wherein the polymeric liquid crystal compound has at least one polymerizable group and exhibits smectic liquid crystallinity, and the photopolymerization initiator satisfies the formula (1) in relation to the polymeric liquid crystal compound: 0 °C ≤ T1 - T2 ≤ 12.0 °C (1). In the formula, T1 is the phase transition temperature at which the polymeric liquid crystal compound is heated to 130 °C in the atmosphere and then cooled to 23 °C at a rate of 5 °C / min while measuring the phase transition temperature, and is the phase transition temperature to the liquid crystal phase presented on the lowest temperature side; T2 is the phase transition temperature at which a mixture formed from 100 parts by mass of the polymeric liquid crystal compound and 5 parts by mass of the photopolymerization initiator is heated to 130 °C in the atmosphere and then cooled to 23 °C at a rate of 5 °C / min while measuring the phase transition temperature, and is the phase transition temperature to the liquid crystal phase presented on the lowest temperature side.

Description

[0001] This application is a divisional application of the invention application with the application date of April 9, 2019, application number 201980024677.X, and invention title "Polymerizable Liquid Crystal Composition". Technical Field

[0002] The present invention relates to a polymerizable liquid crystal composition, and also relates to a polarizing film formed from the above polymerizable liquid crystal composition, a method for manufacturing the same, a polarizing thin film, a polarizing plate, and a display device including the above polarizing film. Background Art

[0003] Conventionally, in various image display panels such as liquid crystal display panels and organic electroluminescence (organic EL) display panels, a polarizing plate is used by being attached to an image display element such as a liquid crystal cell or an organic EL display element. As such a polarizing plate, a polarizing plate having the following configuration is known: a protective layer such as a triacetyl cellulose film is laminated on at least one surface of a polarizing film via an adhesive layer, and the polarizing film is obtained by adsorbing a dichroic compound such as iodine or a dichroic dye on a polyvinyl alcohol-based resin film and orienting it.

[0004] In recent years, there has been a continuous demand for thinning of displays such as image display panels, and further thinning is also required for polarizing plates and polarizing films, which are one of the constituent elements thereof. In response to such a demand, for example, a thin guest-host type polarizing film formed from a polymerizable liquid crystal compound and a dichroic compound has been proposed (Patent Documents 1 to 3).

[0005] Prior Art Documents

[0006] Patent Documents

[0007] Patent Document 1: Japanese Patent Application Laid-Open No. 2007-510946

[0008] Patent Document 2: Japanese Patent Application Laid-Open No. 2016-186075

[0009] Patent Document 3: Japanese Patent Application Laid-Open No. 2013-210624 Summary of the Invention

[0010] Problems to be Solved by the Invention

[0011] However, a guest-host type polarizing film as described in the above patent documents is usually manufactured by curing a composition containing a polymerizable liquid crystal compound, a dichroic pigment, and a polymerization initiator. When active energy rays such as ultraviolet rays are irradiated during the manufacturing process, the dichroic pigment is liable to be modified by active species generated from the polymerization initiator contained in the composition for forming the polarizing film, and thus may not be able to fully satisfy in terms of polarization performance.

[0012] Accordingly, an object of the present invention is to provide a polymerizable liquid crystal composition that is less likely to cause modification of a dichroic pigment during the formation of a polarizing film (polarizer) and is suitable for forming a polarizing film having excellent polarization performance.

[0013] Means for Solving the Problems

[0014] The inventors of the present application conducted intensive studies to solve the above problems and as a result completed the present invention. That is, the present invention provides the following preferred embodiments.

[0015] [1] A polymerizable liquid crystal composition comprising a polymerizable liquid crystal compound, a dichroic pigment, and a photopolymerization initiator, wherein the polymerizable liquid crystal compound has at least one polymerizable group and exhibits smectic liquid crystallinity, and the photopolymerization initiator satisfies the formula (1) in relation to the polymerizable liquid crystal compound:

[0016] 0°C ≤ T1 - T2 ≤ 12.0°C (1)

[0017] [In the formula, T1 is the phase transition temperature at which the polymerizable liquid crystal compound is heated to 130°C in the atmosphere and then cooled to 23°C at a rate of 5°C / min while measuring the phase transition temperature, and is the phase transition temperature to the liquid crystal phase that appears on the lowest temperature side. T2 is the phase transition temperature at which a mixture formed by 100 parts by mass of the polymerizable liquid crystal compound and 5 parts by mass of the photopolymerization initiator is heated to 130°C in the atmosphere and then cooled to 23°C at a rate of 5°C / min while measuring the phase transition temperature, and is the phase transition temperature to the liquid crystal phase that appears on the lowest temperature side.].

[0018] [2] The polymerizable liquid crystal composition according to the above [1], further comprising a solvent.

[0019] [3] The polymerizable liquid crystal composition according to the above [1] or [2], wherein the polymerizable group of the polymerizable liquid crystal compound is acryloyloxy or methacryloyloxy.

[0020] [4] The polymerizable liquid crystal composition according to any one of the above [1] to [3], wherein the dichroic pigment is an azo pigment.

[0021] [5] The polymerizable liquid crystal composition according to any one of the above [1] to [4], wherein the weight average molecular weight of the photopolymerization initiator is 500 or more and 2000 or less.

[0022] [6] The polymerizable liquid crystal composition according to any one of the above [1] to [5], wherein 1 to 10 parts by mass of the photopolymerization initiator is contained relative to 100 parts by mass of the polymerizable liquid crystal compound.

[0023] [7] A polarizing film, which is a cured product of the polymerizable liquid crystal composition described in any one of the above [1] to [6], and shows a Bragg peak in X-ray diffraction measurement.

[0024] [8] The polarizing film as described in the above [7], having a thickness of 0.1 to 5 μm.

[0025] [9] A polarizing thin film, which comprises the polarizing film described in the above [7] or [8] and a transparent film.

[0026]

[10] A polarizing plate, which comprises:

[0027] the polarizing film described in the above 7 or 8 or the polarizing thin film described in the above [9]; and

[0028] A retardation film.

[0029]

[11] The polarizing plate as described in the above

[10] , wherein the retardation film satisfies formula (X), and the angle formed by the slow axis of the retardation film and the absorption axis of the polarizing film is substantially 45°,

[0030] 100 ≤ Re(550) ≤ 180 (X)

[0031] [In the formula, Re(550) represents the in-plane retardation value at a wavelength of 550 nm].

[0032]

[12] The polarizing plate as described in the above

[10] or

[11] , wherein the retardation film satisfies formula (Y):

[0033] Re(450) / Re(550) < 1 (Y)

[0034] [In the formula, Re(450) and Re(550) respectively represent the in-plane retardation values at wavelengths of 450 nm and 550 nm].

[0035]

[13] The polarizing plate as described in any one of the above

[10] to

[12] , wherein the retardation film is composed of a polymer in an oriented state of a polymerizable liquid crystal compound.

[0036]

[14] A display device, which comprises the polarizing thin film described in the above [9] or the polarizing plate as described in any one of the above

[10] to

[13] .

[0037]

[15] A method for manufacturing a polarizing film, which includes the following steps:

[0038] a step of forming a coating film of the polymerizable liquid crystal composition described in any one of the above [1] to [6];

[0039] a step of removing the solvent from the above coating film;

[0040] A step of cooling the polymerizable liquid crystal compound after heating it to a temperature above the phase transition temperature to a liquid phase, so that the polymerizable liquid crystal compound is phase-transitioned to a smectic phase; and,

[0041] A step of polymerizing the polymerizable liquid crystal compound while maintaining the smectic phase state.

[0042] Effects of the invention

[0043] According to the present invention, it is possible to provide a polymerizable liquid crystal composition that is not easily modified with a dichroic pigment when forming a polarizing film and is suitable for forming a polarizing film having excellent polarization performance. Detailed Description of the Invention

[0044] Hereinafter, embodiments of the present invention will be described in detail. The scope of the present invention is not limited to the embodiments described herein, and various modifications can be made without departing from the gist of the present invention.

[0045] <Polymerizable liquid crystal composition>

[0046] The polymerizable liquid crystal composition of the present invention contains a polymerizable liquid crystal compound having at least one polymerizable group and exhibiting smectic liquid crystallinity (hereinafter, also referred to as "polymerizable liquid crystal compound (A)"). By using a polymerizable liquid crystal compound exhibiting smectic liquid crystallinity, a polarizing film with a high degree of orientation order can be formed. The liquid crystal state exhibited by the polymerizable liquid crystal compound (A) is a smectic phase (smectic liquid crystal state), and from the viewpoint of achieving a higher degree of orientation order, a higher-order smectic phase (higher-order smectic liquid crystal state) is more preferred. Here, the so-called higher-order smectic phase refers to a smectic B phase, a smectic D phase, a smectic E phase, a smectic F phase, a smectic G phase, a smectic H phase, a smectic I phase, a smectic J phase, a smectic K phase, and a smectic L phase. Among these, a smectic B phase, a smectic F phase, and a smectic I phase are more preferred. The liquid crystallinity can be thermotropic liquid crystal or lyotropic liquid crystal, and from the aspect of enabling precise film thickness control, thermotropic liquid crystal is preferred. The polymerizable liquid crystal compound can be a monomer, but can also be an oligomer formed by polymerization of polymerizable groups, or a polymer.

[0047] The polymerizable liquid crystal compound (A) is a liquid crystal compound having at least one polymerizable group. Here, the so-called polymerizable group refers to a group that can participate in a polymerization reaction by using active radicals, acids, etc. generated by a polymerization initiator. As the polymerizable group of the polymerizable liquid crystal compound (A), for example, vinyl, vinyloxy, 1-chloroethylene, isopropenyl, 4-vinylphenyl, acryloyloxy, methacryloyloxy, epoxyethyl, oxetanyl, etc. can be cited. Among them, a radical polymerizable group is preferred, acryloyloxy, methacryloyloxy, vinyl, and vinyloxy are more preferred, and acryloyloxy and methacryloyloxy are preferred.

[0048] As the polymeric liquid crystal compound (A), any liquid crystal compound having at least one polymeric group and exhibiting smectic liquid crystallinity may be used without particular limitation, and known polymeric liquid crystal compounds may be used. For example, a compound represented by the formula (A1) (hereinafter, also referred to as "polymeric liquid crystal compound (A1)") may be mentioned.

[0049] U 1 -V 1 -W 1 -(X 1 -Y 1 -) n -X 2 -W 2 -V 2 -U 2 (A1)

[0050] [In the formula (A1),

[0051] X 1 and X 2 each independently represent a divalent aromatic group or a divalent alicyclic hydrocarbon group. Here, the hydrogen atoms contained in the divalent aromatic group or the divalent alicyclic hydrocarbon group may be substituted with a halogen atom, an alkyl group having 1 to 4 carbon atoms, a fluoroalkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a cyano group, or a nitro group, and the carbon atoms constituting the divalent aromatic group or the divalent alicyclic hydrocarbon group may be replaced with an oxygen atom, a sulfur atom, or a nitrogen atom. Among them, at least one of X 1 and X 2 is a 1,4-phenylene group which may have a substituent or a cyclohexane-1,4-diyl group which may have a substituent.

[0052] Y 1 is a single bond or a divalent linking group.

[0053] n is 1 to 3. When n is 2 or more, the plurality of X 1 may be the same or different from each other. X 2 may be the same as or different from any one or all of the plurality of X 1 . In addition, when n is 2 or more, the plurality of Y 1 may be the same or different from each other. From the viewpoint of liquid crystallinity, n is preferably 2 or more.

[0054] U 1 represents a hydrogen atom or a polymeric group.

[0055] U 2 represents a polymeric group.

[0056] W 1 and W 2 each independently represent a single bond or a divalent linking group.

[0057] V 1 and V 2 each independently represents an alkylene group having 1 to 20 carbon atoms which may have substituents, and -CH 2 - constituting the alkylene group may be replaced by -O-, -CO-, -S- or NH-.]

[0058] In the polymerizable liquid crystal compound (A1), X 1 and X 2 are each independently preferably a 1,4-phenylene group which may have substituents or a cyclohexane-1,4-diyl group which may have substituents, and at least one of X 1 and X 2 is a 1,4-phenylene group which may have substituents or a cyclohexane-1,4-diyl group which may have substituents, preferably a trans-cyclohexane-1,4-diyl group. Examples of the substituents which the 1,4-phenylene group which may have substituents or the cyclohexane-1,4-diyl group which may have substituents may optionally have include alkyl groups having 1 to 4 carbon atoms such as methyl, ethyl and butyl, cyano group, and halogen atoms such as chlorine atom and fluorine atom. It is preferably unsubstituted.

[0059] Regarding the polymerizable liquid crystal compound (A1), from the viewpoint of easily exhibiting smectic liquid crystallinity, in formula (A1), the part represented by formula (A1-1) [hereinafter, referred to as partial structure (A1-1).] is preferably an asymmetric structure,

[0060] -(X 1 -Y 1 -) n -X 2 -(A1-1)

[0061] [In the formula, X 1 , Y 1 , X 2 and n each represent the same meaning as described above.].

[0062] Examples of the polymerizable liquid crystal compound (A1) in which the partial structure (A1-1) is an asymmetric structure include:

[0063] A polymerizable liquid crystal compound (A1) in which n is 1 and one X 1 and X 2 have different structures;

[0064] A polymerizable liquid crystal compound (A1) in which n is 2, two Y 1 have the same structure, two X 1 have the same structure, and one X 2 has a structure different from these two X 1 ;

[0065] 2 Xs 1 with W in 1 bonded X 1 is with another X 1 and X 2 are of different structures, and another X 1 with X 2 are polymeric liquid crystal compounds (A1) of the same structure as each other;

[0066] n is 3, 3 Ys 1 are of the same structure as each other, and 3 Xs 1 and 1 X 2 any one of which is a polymeric liquid crystal compound (A1) of a structure different from the other three.

[0067] Y 1 is preferably -CH 2 CH 2 -, -CH 2 O-, -CH 2 CH 2 O-, -COO-, -OCOO-, single bond, -N=N-, -CR a =CR b -, -C≡C-, -CR a =N- or -CO-NR a -. R a and R b each independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. Y 1 is more preferably -CH 2 CH 2 -, -COO- or single bond. When there are multiple Ys 1 present, the Y 2 bonded to X 1 is more preferably -CH 2 CH 2 - or CH 2 O-. When X 1 and X 2 are of the same structure, it is preferable to have two or more Ys with different bonding modes 1 . When there are multiple Ys with different bonding modes 1 present, it becomes an asymmetric structure, and thus has a tendency to easily exhibit smectic liquid crystallinity.

[0068] U 2 is a polymerizable group. U 1 is a hydrogen atom or a polymerizable group, preferably a polymerizable group. Preferably U 1 and U 2They are all polymerizable groups, preferably all free-radical polymerizable groups. As the polymerizable groups, the same groups as those exemplified for the polymerizable groups previously possessed by the polymerizable liquid crystal compound (A) can be cited. U 1 The polymerizable groups represented by 2 and the polymerizable groups represented by U

[0069] As the alkylene group represented by V 1 and V 2 , 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, eicosane-1,20-diyl, etc. can be cited. V 1 and V 2 are preferably alkylene groups having 2 to 12 carbon atoms, more preferably alkylene groups having 6 to 12 carbon atoms.

[0070] As the substituents optionally possessed by the alkylene group, a cyano group, a halogen atom, etc. can be cited, and the alkylene group is preferably unsubstituted, more preferably an unsubstituted linear alkylene group.

[0071] W 1 and W 2 are each independently preferably a single bond, -O-, -S-, -COO- or -OCOO-, more preferably a single bond or -O-.

[0072] As the polymerizable liquid crystal compound (A), any polymerizable liquid crystal compound having at least one polymerizable group and exhibiting smectic liquid crystallinity can be used, and there is no particular limitation. Known polymerizable liquid crystal compounds can be used. As a structure that easily exhibits smectic liquid crystallinity, a molecular structure having asymmetry in the molecular structure is preferred. Specifically, a polymerizable liquid crystal compound having the following partial structures (A-a) to (A-i) and exhibiting smectic liquid crystallinity is more preferred. From the viewpoint of easily exhibiting higher-order smectic liquid crystallinity, a polymerizable liquid crystal compound having the partial structure of (A-a), (A-b) or (A-c) is more preferred. It should be noted that in the following (A-a) to (A-i), * represents a connecting bond (single bond).

[0073] [Chemical formula 1]

[0074]

[0075] As the polymerizable liquid crystal compound (A), for example, compounds represented by the formula (A-1) to the formula (A-25) can be cited. When the polymerizable liquid crystal compound (A) has a cyclohexane-1,4-diyl group, the cyclohexane-1,4-diyl group is preferably a trans form.

[0076] [Chemical formula 2]

[0077]

[0078] [Chemical formula 3]

[0079]

[0080] [Chemical formula 4]

[0081]

[0082] [Chemical formula 5]

[0083]

[0084] [Chemical formula 6]

[0085]

[0086] Among these, at least one selected from the group consisting of compounds represented by the formula (A-2), the formula (A-3), the formula (A-4), the formula (A-5), the formula (A-6), the formula (A-7), the formula (A-8), the formula (A-13), the formula (A-14), the formula (A-15), the formula (A-16), and the formula (A-17) is preferred. As the polymerizable liquid crystal compound (A), one kind can be used alone, or two or more kinds can be used in combination.

[0087] The polymerizable liquid crystal compound (A) can be produced by a known method described in Lub et al., Recl. Trav. Chim. Pays-Bas, 115, 321-328 (1996), or Japanese Patent No. 4719156.

[0088] As long as the effects of the present invention are not impaired, the polymerizable liquid crystal composition of the present invention may contain other polymerizable liquid crystal compounds in addition to the polymerizable liquid crystal compound (A). From the viewpoint of obtaining a polarizing film with a high degree of orientation order, the proportion of the polymerizable liquid crystal compound (A) relative to the total mass of all the polymerizable liquid crystal compounds contained in the polymerizable liquid crystal composition is preferably 51% by mass or more, more preferably 70% by mass or more, and further preferably 90% by mass or more.

[0089] When the polymerizable liquid crystal composition of the present invention contains two or more kinds of polymerizable liquid crystal compounds (A), at least one of them may be a polymerizable liquid crystal compound (A1), or all of them may be polymerizable liquid crystal compounds (A1). By combining a plurality of polymerizable liquid crystal compounds, it is sometimes possible to temporarily maintain the liquid crystallinity even at a temperature below the liquid crystal-crystalline phase transition temperature.

[0090] Relative to the solid components of the polymerizable liquid crystal composition, the content of the polymerizable liquid crystal compound in the polymerizable liquid crystal composition of the present invention is preferably 40 to 99.9% by mass, more preferably 60 to 99% by mass, and still more preferably 70 to 99% by mass. When the content of the polymerizable liquid crystal compound is within the above range, the orientation of the polymerizable liquid crystal compound tends to be improved. In this specification, the so-called solid components refer to the total amount of the components remaining after removing the solvent from the polymerizable liquid crystal composition.

[0091] The polymerizable liquid crystal composition of the present invention contains a dichroic pigment. Here, the dichroic pigment refers to a pigment having the following property: the absorbance in the long axis direction of the molecule is different from the absorbance in the short axis direction. The dichroic pigment that can be used in the present invention is not particularly limited as long as it has the above property, and it can be a dye or a pigment. Two or more dyes or pigments can be used in combination, or a dye and a pigment can be used in combination.

[0092] As the dichroic pigment, a pigment having a maximum absorption wavelength (λ MAX ) in the range of 300 to 700 nm is preferred. As such a dichroic pigment, for example, acridine pigments, oxazine pigments, cyanine pigments, naphthalene pigments, azo pigments, and anthraquinone pigments can be cited.

[0093] As the azo pigment, monoazo pigments, bisazo pigments, trisazo pigments, tetrakisazo pigments, and stilbene azo pigments can be cited, and bisazo pigments and trisazo pigments are preferred. For example, the compound represented by the formula (I) (hereinafter, also referred to as "compound (I)") can be cited.

[0094] K 1 (-N=N-K 2 ) p -N=N-K 3 (I)

[0095] [In the formula (I), K 1 and K 3 each independently represent a phenyl group which may have a substituent, a naphthyl group which may have a substituent, or a monovalent heterocyclic group which may have a substituent. K 2Represents a paraphenylene group which may have a substituent, a naphthalene-1,4-diyl group which may have a substituent, or a divalent heterocyclic group which may have a substituent. p represents an integer from 1 to 4. When p is an integer of 2 or more, multiple K 2 may be the same as or different from each other. Within the range showing absorption in the visible light region, the -N=N- bond can be replaced with a -C≡C-, -COO-, -NHCO-, -N=CH- bond.]

[0096] Examples of the monovalent heterocyclic group include groups obtained by removing one hydrogen atom from heterocyclic compounds such as quinoline, thiazole, benzothiazole, thiophenothiazole, imidazole, benzimidazole, oxazole, and benzoxazole. Examples of the divalent heterocyclic group include groups obtained by removing two hydrogen atoms from the above heterocyclic compounds.

[0097] As K 1 and K 3 the phenyl group, naphthyl group, and monovalent heterocyclic group in, and as for the substituent optionally possessed by the paraphenylene group, naphthalene-1,4-diyl group, and divalent heterocyclic group in K 2 there may be mentioned: an alkyl group having 1 to 4 carbon atoms; an alkoxy group having 1 to 4 carbon atoms such as methoxy, ethoxy, butoxy; a fluoroalkyl group having 1 to 4 carbon atoms such as trifluoromethyl; a cyano group; a nitro group; a halogen atom; a substituted or unsubstituted amino group (a so-called substituted amino group means an amino group having one or two alkyl groups having 1 to 6 carbon atoms, or an amino group in which two substituted alkyl groups are bonded to each other to form an alkane diyl group having 2 to 8 carbon atoms. The unsubstituted amino group is -NH 2 .).

[0098] Among the compounds (I), compounds represented by any one of the following formulas (I-1) to (I-6) are preferred.

[0099] [Chemical formula 7]

[0100]

[0101] [In formulas (I-1) to (I-8),

[0102] B 1 to B 30 each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a cyano group, a nitro group, a substituted or unsubstituted amino group (the definitions of the substituted amino group and the unsubstituted amino group are as described above), a chlorine atom, or a trifluoromethyl group.

[0103] n1 to n4 each independently represents an integer from 0 to 3.

[0104] When n1 is 2 or more, multiple B 2 may be the same as or different from each other,

[0105] When n2 is 2 or more, a plurality of Bs 6 may be the same as or different from each other,

[0106] When n3 is 2 or more, a plurality of Bs 9 may be the same as or different from each other,

[0107] When n4 is 2 or more, a plurality of Bs 14 may be the same as or different from each other.]

[0108] As the above anthraquinone pigment, a compound represented by formula (I-9) is preferred.

[0109] [Chemical formula 8]

[0110]

[0111] [In formula (I-9),

[0112] R 1 ~R 8 each independently represents a hydrogen atom, -R x , -NH 2 , -NHR x , -NR x 2 , -SR x or a halogen atom.

[0113] R x represents an alkyl group having 1 to 4 carbon atoms or an aryl group having 6 to 12 carbon atoms.]

[0114] As the above oxazinone pigment, a compound represented by formula (I-10) is preferred.

[0115] [Chemical formula 9]

[0116]

[0117] [In formula (I-10),

[0118] R 9 ~R 15 each independently represents a hydrogen atom, -R x , -NH 2 , -NHR x , -NR x 2 , -SR x or a halogen atom.

[0119] R x represents an alkyl group having 1 to 4 carbon atoms or an aryl group having 6 to 12 carbon atoms.]

[0120] As the above acridine pigment, a compound represented by the formula (I-11) is preferred.

[0121] [Chemical formula 10]

[0122]

[0123] [In the formula (I-11),

[0124] R 16 ~R 23 each independently represents a hydrogen atom, -R x , -NH 2 , -NHR x , -NR x 2 , -SR x or a halogen atom.

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

[0126] In the formula (I-9), the formula (I-10) and the formula (I-11), as the alkyl group having 1 to 6 carbon atoms of R x , examples thereof include a methyl group, an ethyl group, a propyl group, a butyl group, a pentyl group and a hexyl group, and as the aryl group having 6 to 12 carbon atoms, examples thereof include a phenyl group, a tolyl group, a xylyl group and a naphthyl group.

[0127] As the above cyanine pigment, a compound represented by the formula (I-12) and a compound represented by the formula (I-13) are preferred.

[0128] [Chemical formula 11]

[0129]

[0130] [In the formula (I-12),

[0131] D 1 and D 2 each independently represents a group represented by any one of the formula (I-12a) to the formula (I-12d).

[0132] [Chemical formula 12]

[0133]

[0134] n5 represents an integer of 1 to 3.]

[0135] [Chemical formula 13]

[0136]

[0137] [In the formula (I-13),

[0138] D 3 and D 4 each independently represents a group represented by any one of formulas (I-13a) to (I-13h).

[0139] [Chemical Formula 14]

[0140]

[0141] n6 represents an integer of 1 to 3.]

[0142] Regarding the polymerizable liquid crystal composition of the present invention, the effect of suppressing the photo-degradation of the dichroic pigment in the polarizing film is excellent when forming the polarizing film. Therefore, when using a dichroic pigment that is less resistant to light such as ultraviolet rays in sunlight and is prone to photo-degradation, the effect of the present invention can be particularly significantly exerted. Therefore, the polymerizable liquid crystal composition of the present invention is particularly advantageous when using a dichroic pigment that is prone to photo-degradation. In a preferred embodiment of the present invention, the dichroic pigment contained in the polymerizable liquid crystal composition is preferably an azo pigment.

[0143] The content of the dichroic pigment in the polymerizable liquid crystal composition of the present invention can be appropriately determined according to the type of the dichroic pigment used, etc. It is preferably 0.1 to 50 parts by mass, more preferably 0.1 to 20 parts by mass, and further preferably 0.1 to 12 parts by mass relative to 100 parts by mass of the polymerizable liquid crystal compound. When the content of the dichroic pigment is within the above range, the orientation of the polymerizable liquid crystal compound is not easily disordered, and a polarizing film with a high degree of orientation order can be obtained.

[0144] The polymerizable liquid crystal composition of the present invention contains a photoinitiator. The photoinitiator contained in the polymerizable liquid crystal composition of the present invention is a photoinitiator that satisfies formula (1) in relation to the polymerizable liquid crystal compound contained in the polymerizable liquid crystal composition:

[0145] 0 °C ≤ T1 - T2 ≤ 12.0 °C (1).

[0146] In formula (1), T1 is the phase transition temperature at which the polymerizable liquid crystal compound contained in the above polymerizable liquid crystal composition is heated to 130 °C in the atmosphere and then cooled to 23 °C at a rate of 5 °C / min while measuring the phase transition temperature, and is the phase transition temperature to the liquid crystal phase presented on the lowest temperature side. T2 is the phase transition temperature at which a mixture formed of 100 parts by mass of the above polymerizable liquid crystal compound and 5 parts by mass of the above photoinitiator is heated to 130 °C in the atmosphere and then cooled to 23 °C at a rate of 5 °C / min while measuring the phase transition temperature, and is the phase transition temperature to the liquid crystal phase presented on the lowest temperature side. When the polymerizable liquid crystal composition of the present invention contains two or more polymerizable liquid crystal compounds, the above T1 and T2 can be measured using a polymerizable liquid crystal compound (mixture) formed of the same composition as the polymerizable liquid crystal compounds constituting the polymerizable liquid crystal composition. The detailed measurement methods of T1 and T2 are described in the examples described later.

[0147] Generally, excellent polarization performance can be obtained in the following cases: a dichroic dye is included in a polymerizable liquid crystal compound, and the polymerizable liquid crystal compound and the dichroic dye are oriented with a high degree of order. On the other hand, when a photoinitiator is used in the formation of a polarizing film, while the photoinitiator, the polymerizable liquid crystal compound, and the dichroic dye are in an oriented state, when the polymerizable liquid crystal compound is polymerized, active energy rays such as ultraviolet rays are irradiated, and active species are generated from the photoinitiator. In addition, if the intermolecular distance between the photoinitiator and the dichroic dye is short, the dichroic dye located near the photoinitiator is modified by the active species, and thus there may be a problem as follows: the polarization performance of the obtained polarizing film is reduced.

[0148] The polymerizable liquid crystal composition of the present invention contains a photoinitiator that satisfies the above formula (1), and thus can exhibit a high effect in suppressing the deterioration of polarization performance when forming a polarizing film.

[0149] In formula (1), T1 - T2 becomes an index indicating the influence of the photoinitiator on the phase transition temperature in the liquid crystal state. The larger the value of T1 - T2, the more similar the molecular structures of the polymerizable liquid crystal compound and the photoinitiator are, indicating that they exist in a more highly mixed state in the liquid crystal state, and there are more photoinitiators with a short intermolecular distance from the dichroic dye. That is, the larger the value of T1 - T2, the more easily the dichroic dye is modified during the polymerization of the polymerizable liquid crystal compound. On the other hand, it is speculated that the smaller the value of T1 - T2, the farther the intermolecular distance between the dichroic dye included in the polymerizable liquid crystal compound and the photoinitiator becomes, a high inhibitory effect against the photo-degradation of the dichroic dye can be obtained, and a polarizing film with excellent polarization performance can be obtained.

[0150] Among the photoinitiators contained in the polymerizable liquid crystal composition of the present invention, the value of T1 - T2 is 0°C or higher and 12.0°C or lower, preferably 0.5°C or higher, more preferably 1°C or higher, further preferably 2°C or higher, still more preferably 3°C or higher, and preferably 11.8°C or lower. When the value of T1 - T2 is 0.5°C or higher, the molecular structures of the polymerizable liquid crystal compounds constituting the polymerizable liquid crystal composition and the photoinitiator are not very different. Therefore, it is easy for the photoinitiator and the polymerizable liquid crystal compounds to be oriented with a high degree of order together, and it is easy to fully exhibit the inhibitory effect on the photo-degradation of the dichroic pigment. On the other hand, when the value of T1 - T2 exceeds 12.0°C, there is a tendency that the molecular structures of the polymerizable liquid crystal compounds constituting the polymerizable liquid crystal composition are similar to those of the photoinitiator, and the photoinitiator is likely to exist closer to the dichroic pigment, and it is easy for the dichroic pigment to be modified by the active species generated by the photoinitiator. When the value of T1 - T2 is within the above range, the photoinitiator is not likely to exist near the dichroic pigment (which is included in the polymerizable liquid crystal compound), and a high inhibitory effect on the modification of the dichroic pigment can be expected.

[0151] The photoinitiator only needs to be a compound that satisfies the above formula (1) in relation to the polymerizable liquid crystal compounds contained in the polymerizable liquid crystal composition and can initiate the polymerization reaction of the polymerizable liquid crystal compounds, and its type is not particularly limited. Specifically, photoinitiators that can generate active free radicals or acids by the action of light can be cited. Among them, photoinitiators that generate free radicals by the action of light are preferred. The photoinitiator can be used alone or in combination of two or more.

[0152] As the photoinitiator, for example, photoinitiators that generate active free radicals can be cited. As this photoinitiator, there are self-cleavage type photoinitiators and hydrogen abstraction type photoinitiators.

[0153] As the self-cleavage type photoinitiator, self-cleavage type benzoin compounds, acetophenone compounds, hydroxyacetophenone compounds, α-aminobenzophenone compounds, oxime ester compounds, acylphosphine oxide compounds, azo compounds, etc. can be used. In addition, as the hydrogen abstraction type photoinitiator, hydrogen abstraction type benzophenone compounds, benzoin ether compounds, benzil ketal compounds, dibenzocycloheptanone compounds, anthraquinone compounds, xanthene compounds, thioxanthene compounds, halogenated acetophenone compounds, dialkoxyacetophenone compounds, halogenated bisimidazole compounds, halogenated triazine compounds, triazine compounds, etc. can be used.

[0154] As the photoinitiator that generates an acid, iodonium salts and sulfonium salts, etc. can be used.

[0155] From the viewpoint of the reaction efficiency at low temperatures, self-cleaving photoinitiators are preferred, and particularly preferred are acetophenone compounds, hydroxyacetophenone compounds, α-aminobenzophenone compounds, and oxime ester compounds.

[0156] Examples of photoinitiators include the following initiators.

[0157] Benzoin compounds such as benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether, and benzoin isobutyl ether;

[0158] Hydroxyacetophenone compounds such as 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1,2-diphenyl-2,2-dimethoxyethan-1-one, 2-hydroxy-2-methyl-1-[4-(2-hydroxyethoxy)phenyl]propan-1-one, 1-hydroxycyclohexyl phenyl ketone, and oligomers of 2-hydroxy-2-methyl-1-[4-(1-methylethenyl)phenyl]propan-1-one;

[0159] α-Aminobenzophenone compounds such as 2-methyl-2-morpholino-1-(4-methylthiophenyl)propan-1-one and 2-dimethylamino-2-benzyl-1-(4-morpholinophenyl)butan-1-one;

[0160] Oxime ester compounds such as 1,2-octanedione, 1-[4-(phenylthio)-2-(O-benzoyl oxime)]-ethanone, 1-[9-ethyl-6-(2-methylbenzoyl)-9H-carbazol-3-yl]-, 1-(O-acetyl oxime);

[0161] Acylphosphine oxide compounds such as 2,4,6-trimethylbenzoyl diphenylphosphine oxide and bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide;

[0162] Benzophenone compounds such as benzophenone, methyl o-benzoylbenzoate, 4-phenylbenzophenone, 4-benzoyl-4'-methyldiphenyl sulfide, 3,3',4,4'-tetra(tert-butylperoxycarbonyl)benzophenone, and 2,4,6-trimethylbenzophenone;

[0163] Dialkoxyacetophenone compounds such as diethoxyacetophenone;

[0164] Triazine compounds such as 2,4-bis(trichloromethyl)-6-(4-methoxyphenyl)-1,3,5-triazine, 2,4-bis(trichloromethyl)-6-(4-methoxynaphthyl)-1,3,5-triazine, 2,4-bis(trichloromethyl)-6-(4-methoxystyryl)-1,3,5-triazine, 2,4-bis(trichloromethyl)-6-[2-(5-methylfuran-2-yl)vinyl]-1,3,5-triazine, 2,4-bis(trichloromethyl)-6-[2-(furan-2-yl)vinyl]-1,3,5-triazine, 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.

[0165] Regarding the photopolymerization initiator, for example, it can be appropriately selected from the above-mentioned photopolymerization initiators according to the relationship with the polymerizable liquid crystal compound contained in the polymerizable liquid crystal composition.

[0166] As the photopolymerization initiator, commercially available photopolymerization initiators can be used. Examples of commercially available photopolymerization initiators include: Irgacure (registered trademark) 907, 184, 651, 819, 250, and 369, 379, 127, 754, OXE01, OXE02, OXE03 (manufactured by BASF); Omnirad BCIM, Esacure 1001M, Esacure KIP160 (manufactured by IDM Resins B.V.); SEIKUOL (registered trademark) BZ, Z, and BEE (manufactured by Seiko Chemical Co., Ltd.); kayacure (registered trademark) BP100 and UVI-6992 (manufactured by Dow Chemical Co., Ltd.); Adeka Optomer SP-152, N-1717, N-1919, SP-170, Adeka arc Luz NCI-831, Adeka arc Luz NCI-930 (manufactured by Adeka Corporation); TAZ-A and TAZ-PP (manufactured by Nihon Siberhegner Co., Ltd.); and TAZ-104 (manufactured by Sanwa Chemical Co., Ltd.); etc.

[0167] The weight-average molecular weight of the photopolymerization initiator is preferably 500 or more and 2,000 or less, more preferably 600 or more, further preferably 700 or more, more preferably 1,500 or less, and further preferably 1,000 or less. When the weight-average molecular weight of the photopolymerization initiator is at least the above lower limit value, there is a tendency as follows: it is not easily oriented together with the polymerizable liquid crystal compound, and it is not easy to modify the dichroic pigment encapsulated in the polymerizable liquid crystal compound. When the weight-average molecular weight of the photopolymerization initiator is at most the above upper limit value, it is possible to suppress the orientation disorder of the polymerizable liquid crystal compound caused by the photopolymerization initiator, and it is possible to obtain a polarizing film having excellent polarizing properties while maintaining a high degree of orientation order.

[0168] As the photopolymerization initiator, a photopolymerization initiator having a large steric hindrance and low linearity in terms of molecular structure is not easily oriented together with the polymerizable liquid crystal compound, and there is a tendency that the modification of the dichroic pigment is not likely to occur. As the photopolymerization initiator having such a molecular structure, for example, the following compounds can be cited.

[0169] [Chemical formula 15]

[0170]

[0171] [Chemical formula 16]

[0172]

[0173] [Chemical formula 17]

[0174]

[0175] [Chemical formula 18]

[0176]

[0177] [Chemical formula 19]

[0178]

[0179] [Chemical formula 20]

[0180]

[0181] [Chemical formula 21]

[0182]

[0183] [Chemical formula 22]

[0184]

[0185] [Chemical formula 23]

[0186]

[0187] [Chemical formula 24]

[0188]

[0189] [Chemical formula 25]

[0190]

[0191] [Chemical formula 26]

[0192]

[0193] Among them, without being limited to these, considering from the aspect that the steric hindrance is large in terms of molecular structure and there is a tendency for the modification of the dichroic pigment to be difficult to occur, as the photoinitiator, it is preferably a compound having a partial structure represented by the following (B-1). In addition, from the viewpoint of the reaction mechanism of the photoinitiator, an oxime ester compound and a benzophenone compound are preferred, and an oxime ester compound is more preferred.

[0194] [Chemical formula 27]

[0195]

[0196] In the formula (B-1), "*" represents a connecting bond (single bond), the number of connecting bonds on the benzene ring can be 1 to 5, and its position is not particularly limited. X represents NR1, S or C=O, and R1 represents an alkyl group having 1 to 4 carbon atoms. Y1 and Y2 represent hydrogen atoms, or a connecting group between Y1 and Y2.

[0197] The content of the above photoinitiator in the polymerizable liquid crystal composition of the present invention is preferably 1 to 10 parts by mass, more preferably 1 to 8 parts by mass, further preferably 2 to 8 parts by mass, and particularly preferably 4 to 8 parts by mass with respect to 100 parts by mass of the polymerizable liquid crystal compound. When the content of the photoinitiator is within the above range, the polymerization reaction of the polymerizable liquid crystal compound can be carried out without significantly disturbing the orientation of the polymerizable liquid crystal compound.

[0198] From the viewpoints of circuit contamination during manufacturing and operation, the polymerization rate of the polymerizable liquid crystal compound in the present invention is preferably 60% or more, more preferably 65% or more, and further preferably 70% or more.

[0199] The polymerizable liquid crystal composition may further contain a photosensitizer. By using a photosensitizer, the polymerization reaction of the polymerizable liquid crystal compound can be further promoted. Examples of the photosensitizer include xanthone compounds such as xanthone and thioxanthone (for example, 2,4-diethylthioxanthone, 2-isopropylthioxanthone); anthracene compounds such as anthracene and alkoxy-containing anthracene (for example, dibutoxyanthracene); phenothiazine, rubrene, and the like. The photosensitizer may be used alone or in combination of two or more.

[0200] When the polymerizable liquid crystal composition of the present invention contains a photosensitizer, its content may be appropriately determined according to the types and amounts of the photoinitiator and the polymerizable liquid crystal compound. Preferably, it is 0.1 to 30 parts by mass, more preferably 0.5 to 10 parts by mass, and further preferably 0.5 to 8 parts by mass with respect to 100 parts by mass of the polymerizable liquid crystal compound.

[0201] In addition, the polymerizable liquid crystal composition of the present invention may contain a leveling agent. The leveling agent has a function of adjusting the fluidity of the polymerizable liquid crystal composition and making the coating film obtained by coating the polymerizable liquid crystal composition more flat. Specifically, a surfactant can be cited. As the leveling agent, it is preferable to select at least one from the group consisting of a leveling agent mainly composed of a polyacrylate compound and a leveling agent mainly composed of a fluorine atom-containing compound. The leveling agent may be used alone or in combination of two or more.

[0202] Examples of the leveling agent mainly composed of a polyacrylate compound include "BYK-350", "BYK-352", "BYK-353", "BYK-354", "BYK-355", "BYK-358N", "BYK-361N", "BYK-380", "BYK-381", and "BYK-392" (BYK Chemie).

[0203] As a leveling agent mainly composed of a compound containing a fluorine atom, for example, "MEGAFACE (registered trademark) R-08", MEGAFACE "R-30", MEGAFACE "R-90", MEGAFACE "F-410", MEGAFACE "F-411", MEGAFACE "F-443", MEGAFACE "F-445", MEGAFACE "F-470", MEGAFACE "F-471", MEGAFACE "F-477", MEGAFACE "F-479", MEGAFACE "F-482", and MEGAFACE "F-483" (DIC Corporation); "Surflon (registered trademark) S-381", Surflon "S-382", Surflon "S-383", Surflon "S-393", Surflon "SC-101", Surflon "SC-105", "KH-40", and "SA-100" (AGC SEIMI CHEMICAL Co., Ltd.); "E1830", "E5844" (Daikin Fine Chemical Laboratory Co., Ltd.); "EFTOP EF301", "EFTOP EF303", "EFTOPEF351", and "EFTOP EF352" (Mitsubishi Materials Electronic Chemicals Co., Ltd.) can be cited.

[0204] When the polymerizable liquid crystal composition of the present invention contains a leveling agent, its content is preferably 0.05 to 5 parts by mass, more preferably 0.05 to 3 parts by mass, based on 100 parts by mass of the polymerizable liquid crystal compound. When the content of the leveling agent is within the above range, it is easy to make the polymerizable liquid crystal compound horizontally oriented and unevenness is not easily generated, and there is a tendency to obtain a smoother polarizing film.

[0205] The polymerizable liquid crystal composition of the present invention may contain other additives in addition to the photosensitizer and the leveling agent. As other additives, antioxidants, release agents, stabilizers, colorants such as bluing agents, flame retardants, and lubricants can be cited. When the polymerizable liquid crystal composition contains other additives, the content of the other additives is preferably more than 0% and 20% by mass or less, more preferably more than 0% and 10% by mass or less, based on the solid content of the polymerizable liquid crystal composition.

[0206] The polymerizable liquid crystal composition of the present invention may contain a solvent. Generally, compounds exhibiting smectic liquid crystallinity have a high viscosity. Therefore, by adding a solvent to the polymerizable liquid crystal composition, it becomes easier to coat, and as a result, the formation of a polarizing film often becomes easier. The solvent can be appropriately selected according to the solubility of the polymerizable liquid crystal compound and the dichroic pigment. For example, alcohol solvents such as water, methanol, ethanol, ethylene glycol, isopropyl alcohol, propylene glycol, methyl cellosolve, butyl cellosolve, and propylene glycol monomethyl ether, ester solvents such as ethyl acetate, butyl acetate, ethylene glycol methyl ether acetate, γ-butyrolactone, propylene glycol methyl ether acetate, and ethyl lactate, ketone solvents such as acetone, methyl ethyl ketone, cyclopentanone, cyclohexanone, methyl amyl ketone, and methyl isobutyl ketone, aliphatic hydrocarbon solvents such as pentane, hexane, and heptane, aromatic hydrocarbon solvents such as toluene and xylene, nitrile solvents such as acetonitrile, ether solvents such as tetrahydrofuran and dimethoxyethane, and chlorinated hydrocarbon solvents such as chloroform and chlorobenzene; and so on. These solvents can be used alone or in combination of two or more. With respect to 100 parts by mass of the solid components constituting the polymerizable liquid crystal composition, the content of the solvent is preferably 100 to 1900 parts by mass, more preferably 150 to 900 parts by mass, and still more preferably 180 to 600 parts by mass.

[0207] The polymerizable liquid crystal composition of the present invention can be produced by using a method for producing a polymerizable liquid crystal composition known in the past. Generally, it can be prepared by mixing and stirring a polymerizable liquid crystal compound, a dichroic pigment, a photopolymerization initiator, and, if necessary, the above-mentioned additives and solvents.

[0208] <Polarizing film>

[0209] The polymerizable liquid crystal composition of the present invention has a structure in which the dichroic pigment is not easily modified during curing based on actinic ray irradiation. Therefore, a polarizing film having excellent polarization performance can be obtained, and it can be suitably used for the production of a polarizing film.

[0210] For a polarizing film with a high degree of orientation order, in X-ray diffraction measurement, Bragg peaks from higher-order structures such as a hexagonal phase and a crystalline phase can be obtained. The so-called Bragg peak refers to a peak from the periodic structure of the molecular orientation plane. Therefore, in the polarizing film formed from the polymerizable liquid crystal composition of the present invention, the polymerizable liquid crystal compound or its polymer is preferably oriented in such a way that the polarizing film shows Bragg peaks in X-ray diffraction measurement, and more preferably in a "horizontal orientation" in which the molecules of the polymerizable liquid crystal compound are oriented along the direction of the absorbed light. In the present invention, it is preferred that the periodic interval of the molecular orientation plane is of the polarizing film. The achievement of a high degree of orientation order such as showing Bragg peaks can be realized by controlling the types of the polymerizable liquid crystal compounds used, the types of the photopolymerization initiators, their amounts, the types of the dichroic pigments, their amounts, and the like.

[0211] As described above, by using a photopolymerization initiator that satisfies formula (1) in relation to the polymeric liquid crystal compound, it is possible to suppress the modification of the dichroic pigment caused by the active species generated by the photopolymerization initiator during the polymerization of the polymeric liquid crystal compound, and it is possible to obtain a polarizing film having excellent polarization performance while maintaining a high degree of orientation order of the polymeric liquid crystal compound. Therefore, the present invention also targets the following polarizing film, which is a cured product of the polymeric liquid crystal composition of the present invention and shows a Bragg peak in X-ray diffraction measurement.

[0212] The polarizing film of the present invention can be produced, for example, by a method including the following steps:

[0213] A step of forming a coating film of the polymeric liquid crystal composition of the present invention;

[0214] A step of removing the solvent from the above coating film;

[0215] A step of heating to a temperature above the phase transition temperature of the polymeric liquid crystal compound to a liquid phase and then cooling to cause the polymeric liquid crystal compound to phase transition into a smectic phase (smectic liquid crystal state); and,

[0216] A step of polymerizing the polymeric liquid crystal compound while maintaining the above smectic phase (smectic liquid crystal state).

[0217] The formation of the coating film of the polymeric liquid crystal composition can be carried out, for example, by coating the polymeric liquid crystal composition, particularly the polymeric liquid crystal composition whose viscosity is adjusted by adding a solvent (hereinafter, also referred to as "composition for forming a polarizing film") on a substrate, an alignment film described later, etc. In addition, the composition for forming a polarizing film can also be directly coated on the retardation film, other layers constituting the polarizing plate of the present invention.

[0218] The substrate is usually a transparent substrate. It should be noted that when the substrate is not disposed on the display surface of the display element, for example, when the laminate obtained by removing the substrate from the polarizing film is disposed on the display surface of the display element, the substrate can be opaque. The so-called transparent substrate refers to a substrate having transparency that allows light (especially visible light) to pass through. The so-called transparency refers to the property that the transmittance is 80% or more with respect to light in the wavelength range of 380 to 780 nm. As a specific transparent substrate, a light-transmissive resin substrate can be cited. As the resin constituting the light-transmissive resin substrate, the following can be cited: polyolefins such as polyethylene and polypropylene; cyclic olefin resins such as norbornene-based polymers; polyvinyl alcohol; polyethylene terephthalate; polymethacrylate; polyacrylate; cellulose esters such as triacetyl cellulose, diacetyl cellulose, and cellulose acetate propionate; polyethylene naphthalate; polycarbonate; polysulfone; polyethersulfone; polyether ketone; polyphenylene sulfide and polyphenylene ether, etc. From the viewpoints of ease of acquisition and transparency, polyethylene terephthalate, polymethacrylate, cellulose ester, cyclic olefin resin or polycarbonate is preferred. Cellulose ester is a substance obtained by esterifying a part or all of the hydroxyl groups contained in cellulose and can be easily obtained on the market. In addition, a cellulose ester substrate can also be easily obtained on the market. As commercially available cellulose ester substrates, for example, "Fujitac Film" (Fujifilm Corporation); "KC8UX2M", "KC8UY" and "KC4UY" (Konica Minolta Opto Products Co., Ltd.) etc. can be cited.

[0219] The properties required for the substrate vary depending on the composition of the polarizing film. Generally, a substrate with as small a retardation as possible is preferred. As a substrate with as small a retardation as possible, cellulose ester films without retardation such as ZeroTAC (Konica Minolta Opto, Inc.) and Z-TAC (Fujifilm Corporation) can be cited. In addition, an unstretched cyclic olefin resin substrate is also preferred. Hard coat treatment, antireflection treatment, antistatic treatment, etc. can be performed on the surface of the substrate on which the polarizing film is not laminated.

[0220] When the thickness of the substrate is too thin, the strength decreases and there is a tendency for poor processability. Therefore, it is usually 5 to 300 μm, preferably 20 to 200 μm, more preferably 20 to 100 μm.

[0221] As a method of coating the polarizing film-forming composition on a substrate or the like, known methods such as spin coating method, extrusion method, gravure coating method, die coating method, bar coating method, coater method and other coating methods, flexographic printing method and other printing methods can be cited.

[0222] Next, under the condition that the polymerizable liquid crystal compound contained in the coating film obtained from the composition for forming a polarizing film does not polymerize, the solvent is removed by drying or the like to form a dry coating film. Examples of the drying method include natural drying, ventilation drying, heat drying, and reduced-pressure drying methods.

[0223] In addition, in order to change the polymerizable liquid crystal compound into a liquid phase, after raising the temperature above the temperature at which the polymerizable liquid crystal compound changes into a liquid phase, the temperature is lowered to change the polymerizable liquid crystal compound into a smectic phase (smectic liquid crystal state). The phase change can be carried out after removing the solvent in the above coating film, or can be carried out simultaneously with the removal of the solvent.

[0224] By polymerizing the polymerizable liquid crystal compound while maintaining the smectic liquid crystal state of the polymerizable liquid crystal compound, a polarizing film is formed in the form of a cured layer of the polymerizable liquid crystal composition. As the polymerization method, a photopolymerization method is preferably used. In photopolymerization, as the light irradiated on the dry coating film, it can be appropriately selected according to the type of the photoinitiator contained in the dry coating film, the type of the polymerizable liquid crystal compound (especially the type of the polymerizable group possessed by the polymerizable liquid crystal compound), and its amount. Specific examples thereof include one or more types of light selected from the group consisting of visible light, ultraviolet light, infrared light, X-rays, α-rays, β-rays, and γ-rays, and active electron beams. Among them, from the viewpoints of easily controlling the progress of the polymerization reaction and being able to use a device widely used in the art as a photopolymerization device, ultraviolet light is preferred, and the types of the polymerizable liquid crystal compound and the photoinitiator contained in the polymerizable liquid crystal composition are preferably selected in advance in such a way that photopolymerization can be carried out by ultraviolet light. In addition, during polymerization, the polymerization temperature can also be controlled by irradiating light while cooling the dry coating film by using an appropriate cooling means. If the polymerization of the polymerizable liquid crystal compound is carried out at a lower temperature by adopting such a cooling means, a polarizing film can be appropriately formed even if a substrate with relatively low heat resistance is used. When carrying out photopolymerization, a patterned polarizing film can also be obtained by masking, developing, or the like.

[0225] Examples of the light source for the above-mentioned actinic 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 to 440 nm, chemical lamps, black lights, microwave-excited mercury lamps, metal halide lamps, and the like.

[0226] The ultraviolet irradiation intensity is usually 10 to 3,000 mW / cm 2。The intensity of ultraviolet irradiation is preferably the intensity in the wavelength region effective for the activation of the photopolymerization initiator. The irradiation time of the light is usually from 0.1 second to 10 minutes, preferably from 1 second to 5 minutes, more preferably from 5 seconds to 3 minutes, and further preferably from 10 seconds to 1 minute. When irradiated with such ultraviolet intensity once or more times, the cumulative light amount is 10 to 3,000 mJ / cm 2 , preferably 50 to 2,000 mJ / cm 2 , more preferably 100 to 1,000 mJ / cm 2 。

[0227] By carrying out photopolymerization, the polymerizable liquid crystal compound is polymerized while maintaining a liquid crystal state of a smectic phase, preferably a higher-order smectic phase, to form a polarizing film. For the polarizing film obtained by polymerizing the polymerizable liquid crystal compound while maintaining a liquid crystal state of a smectic phase, also accompanied by the action of the above dichroic pigment, compared with the conventional guest-host type polarizing film, that is, the polarizing film formed from a nematic liquid crystal state, it has the advantage of high polarizing performance. In addition, compared with the film formed by simply coating a dichroic pigment and a lyotropic liquid crystal, it also has the advantage of excellent strength.

[0228] The thickness of the polarizing film can be appropriately selected according to the applicable display device, and is preferably a film of 0.1 μm or more and 5 μm or less, more preferably 0.3 μm or more and 4 μm or less, and further preferably 0.5 μm or more and 3 μm or less. When the film thickness is thinner than this range, there is a case where the required light absorption cannot be obtained, and when the film thickness is thicker than this range, there is a tendency that the orientation control force by the alignment film decreases and orientation defects are likely to occur.

[0229] The polarizing film is preferably formed on the alignment film. The alignment film is a film having an orientation control force for causing the polymerizable liquid crystal compound to be liquid crystal aligned in a desired direction. As the alignment film, an alignment film containing an orientation polymer, a photo-alignment film, a groove alignment film having concavo-convex patterns and a plurality of grooves on the surface, a stretched film stretched in the alignment direction, etc. are exemplified, and from the viewpoints of the accuracy of the alignment angle and the quality, a photo-alignment film is preferred.

[0230] Examples of the orientation polymer include polyamides having an amide bond in the molecule, gelatin, polyimides having an imide bond in the molecule, polyamic acids which are hydrolysis products thereof, polyvinyl alcohol, alkyl-modified polyvinyl alcohol, polyacrylamide, polyoxazole, polyethyleneimine, polystyrene, polyvinylpyrrolidone, polyacrylic acid, and polyacrylate compounds. Among them, polyvinyl alcohol is preferred. The orientation polymer may be used alone or in combination of two or more.

[0231] The orientation film containing the orientation polymer is usually obtained by the following methods: coating a composition obtained by dissolving the orientation polymer in a solvent (hereinafter sometimes referred to as "orientation polymer composition") on a substrate and removing the solvent; or coating the orientation polymer composition on a substrate, removing the solvent, and performing rubbing (rubbing method). Examples of the solvent include the same solvents as those exemplified above as solvents that can be used in forming a polarizing film.

[0232] Regarding the concentration of the orientation polymer in the orientation polymer composition, as long as it is within the range where the orientation polymer material can be completely dissolved in the solvent, in terms of the solid content conversion with respect to the solution, it is preferably 0.1 to 20%, and more preferably about 0.1 to 10%.

[0233] As the orientation polymer composition, commercially available orientation film materials can be directly used. Examples of the commercially available orientation film materials include SUNEVER (registered trademark, manufactured by Nissan Chemical Industries, Ltd.), OPTOMER (registered trademark, manufactured by JSR Corporation), etc.

[0234] Examples of the method of coating the orientation polymer composition on a substrate include the same methods as those exemplified as the methods of coating the composition for forming a polarizing film on a substrate.

[0235] Examples of the method of removing the solvent contained in the orientation polymer composition include natural drying method, ventilation drying method, heat drying, and reduced pressure drying method, etc.

[0236] In order to impart orientation control force to the orientation film, rubbing treatment (rubbing method) can be performed as needed.

[0237] Examples of the method of imparting orientation control force by the rubbing method include: a method of bringing a rubbing roller wound with a rubbing cloth and rotating into contact with a film of the orientation polymer formed on the substrate surface by coating the orientation polymer composition on the substrate and annealing.

[0238] A photo-alignment film is usually obtained by coating a substrate with a composition containing a polymer or monomer having a photo-reactive group and a solvent (hereinafter, also referred to as "composition for forming a photo-alignment film") and irradiating polarized light (preferably polarized UV light). The photo-alignment film is more preferable in terms of being able to arbitrarily control the direction of the alignment control force by selecting the polarization direction of the irradiated polarized light.

[0239] The so-called photo-reactive group refers to a group that generates a liquid crystal alignment ability by photo-irradiation. Specifically, groups participating in photo-reactions such as orientation induction or isomerization reaction, dimerization reaction, photo-crosslinking reaction, or photo-decomposition reaction of molecules occurring by photo-irradiation, which are the origin of the liquid crystal alignment ability, can be cited. Among them, groups participating in the dimerization reaction or photo-crosslinking reaction are preferable in terms of excellent orientation. As the photo-reactive group, a group having an unsaturated bond, particularly a double bond, is preferable, and a group having at least one selected from the group consisting of a carbon-carbon double bond (C═C bond), a carbon-nitrogen double bond (C═N bond), a nitrogen-nitrogen double bond (N═N bond), and a carbon-oxygen double bond (C═O bond) is particularly preferable.

[0240] As the photo-reactive group having a C═C bond, vinyl, polyene group, stilbene group, stilbazole group, stilbazolinium group, chalcone group, and cinnamoyl group can be cited. As the photo-reactive group having a C═N bond, groups having structures such as aromatic Schiff base and aromatic hydrazone can be cited. As the photo-reactive group having an N═N bond, azobenzene group, azonaphthyl group, aromatic heterocyclic azo group, bisazo group, formazyl group, and groups having an azoxybenzene structure can be cited. As the photo-reactive group having a C═O bond, benzophenone group, coumarin group, anthraquinone group, and maleimide group can be cited. These groups may have substituents such as an alkyl group, an alkoxy group, an aryl group, an allyloxy group, a cyano group, an alkoxycarbonyl group, a hydroxyl group, a sulfonic acid group, and a haloalkyl group.

[0241] Among them, photo-reactive groups participating in the photo-dimerization reaction are preferable. From the viewpoints that the amount of polarized light irradiation required for photo-alignment is less and it is easy to obtain a photo-alignment film having excellent thermal stability and stability over time, cinnamoyl group and chalcone group are preferable. As the polymer having a photo-reactive group, a polymer in which the terminal portion of the side chain of the polymer has a cinnamoyl group having a cinnamic acid structure is particularly preferable.

[0242] By coating the composition for forming a photo-alignment film on a substrate, a photo-alignment induction layer can be formed on the substrate. As the solvent contained in the composition, the same solvents as those exemplified above as solvents that can be used in forming a polarizing film can be cited, and can be appropriately selected according to the solubility of the polymer or monomer having a photo-reactive group.

[0243] The content of the polymer or monomer having a photoreactive group in the composition for forming a photo-aligned film can be appropriately adjusted according to the type of the polymer or monomer and the thickness of the target photo-aligned film, and is preferably at least 0.2% by mass, more preferably in the range of 0.3 to 10% by mass, based on the mass of the composition for forming a photo-aligned film. The composition for forming a photo-aligned film may contain polymer materials such as polyvinyl alcohol and polyimide, and photosensitizers within a range that does not significantly impair the properties of the photo-aligned film.

[0244] As a method for coating the composition for forming a photo-aligned film on a substrate, the same methods as those for coating an alignment polymer composition on a substrate can be cited. As a method for removing the solvent from the coated composition for forming a photo-aligned film, natural drying method, ventilation drying method, heat drying, and reduced-pressure drying method, etc. can be cited.

[0245] In order to irradiate polarized light, it can be in the form of directly irradiating polarized UV light on the product obtained by removing the solvent from the composition for forming a photo-aligned film coated on a substrate, or in the form of irradiating polarized light from the substrate side and making the polarized light pass through for irradiation. In addition, the polarized light is particularly preferably substantially parallel light. The wavelength of the irradiated polarized light is a wavelength in the wavelength region where the photoreactive group of the polymer or monomer having a photoreactive group can absorb light energy. Specifically, UV (ultraviolet rays) in the range of 250 to 400 nm is particularly preferred. As a light source for this polarized light irradiation, xenon lamp, high-pressure mercury lamp, ultra-high-pressure mercury lamp, metal halide lamp, UV lasers such as KrF and ArF, etc. can be cited, and high-pressure mercury lamp, ultra-high-pressure mercury lamp, and metal halide lamp are more preferred. Among these, high-pressure mercury lamp, ultra-high-pressure mercury lamp, and metal halide lamp are preferred because of the large emission intensity of ultraviolet rays with a wavelength of 313 nm. By making the light from the above light source pass through an appropriate polarizer for irradiation, polarized UV light can be irradiated. As the polarizer, a polarizing filter, a polarizing prism such as Glan-Thompson and Glan-Taylor, and a wire-grid type polarizer can be used.

[0246] It should be noted that when performing rubbing or polarized light irradiation, if masking is performed, multiple regions (patterns) with different liquid crystal alignment directions can also be formed.

[0247] A groove alignment film is a film having an uneven pattern or multiple grooves (channels) on the film surface. When a polymerizable liquid crystal compound is coated on a film having multiple linear grooves arranged at equal intervals, the liquid crystal molecules are aligned in the direction along the groove.

[0248] As a method for obtaining a groove-aligned film, the following methods can be mentioned: a method in which after exposing the surface of a photosensitive polyimide film through an exposure mask having a slit with a pattern shape, development and rinsing treatments are performed to form an uneven pattern; a method in which a layer of a UV curable resin before curing is formed on a plate-shaped original having grooves on its surface, the formed resin layer is transferred to a substrate, and then it is cured; and a method in which a roller-shaped original having a plurality of grooves is pressed against a film of a UV curable resin before curing formed on a substrate to form unevenness, and then it is cured; and so on.

[0249] The thickness of the alignment film (an alignment film containing an alignment polymer or a photo-alignment film) is usually in the range of 10 to 10,000 nm, preferably in the range of 10 to 1,000 nm, more preferably 500 nm or less, further preferably in the range of 10 to 200 nm, and particularly preferably in the range of 50 to 150 nm.

[0250] <Polarizing thin film>

[0251] The present invention includes a polarizing thin film, which is composed of the polarizing film of the present invention and a transparent film. As the transparent film constituting the polarizing thin film of the present invention, a long strip-shaped rolled film is preferred in terms of continuous manufacturing. As the resin constituting the film substrate, for example, the following can be mentioned: polyolefins such as polyethylene, polypropylene, and norbornene-based polymers; cyclic olefin-based resins; polyvinyl alcohol; polyethylene terephthalate; polymethacrylate; polyacrylate; cellulose esters such as triacetyl cellulose, diacetyl cellulose, and cellulose acetate propionate; polyethylene naphthalate; polycarbonate; polysulfone; polyethersulfone; polyether ketone; polyphenylene sulfide; and polyphenylene ether; and other plastics.

[0252] In addition, commercially available cellulose ester substrates such as "Fujitac Film" (manufactured by Fujifilm Corporation); "KC8UX2M", "KC8UY", and "KC4UY" (the above are manufactured by Konica Minolta Opto, Inc.) can be used. As commercially available cyclic olefin resins, "Topas" (registered trademark) (manufactured by Ticona GmbH (Germany)), "ARTON" (registered trademark) (manufactured by JSR Corporation), "ZEONOR", "ZEONEX" (registered trademarks) (the above are manufactured by Nippon Zeon Co., Ltd.), and "APEL" (registered trademark) (manufactured by Mitsui Chemicals, Inc.) can be cited. Such cyclic olefin resins can be formed into films by known means such as solvent casting method and melt extrusion method to obtain substrates. Commercially available cyclic olefin resin substrates can also be used. As commercially available cyclic olefin resin substrates, "ESCENA" (registered trademark), "SCA40" (registered trademark) (the above are manufactured by Sekisui Chemical Co., Ltd.), "ZEONOR FILM" (registered trademark) (manufactured by Optes Co., Ltd.), and "ARTON FILM" (registered trademark) (manufactured by JSR Corporation) can be cited.

[0253] In the polarizing film of the present invention, the transparent film can be laminated on only one side of the polarizing film or on both sides. When the polarizing film of the present invention includes a plurality of transparent films, they can be the same or different from each other. In addition, the polarizing film and the transparent film can be in contact with each other or separated from each other. Usually, the transparent film can be adhered to the polarizing film via an adhesive layer or a binder layer.

[0254] Regarding the thickness of the transparent film constituting the polarizing film of the present invention, from the perspective of quality that can be practically operated, the thinner the better, but when it is too thin, the strength decreases and the processability tends to be poor. The thickness of the substrate is usually 5 μm to 300 μm, preferably 20 μm to 200 μm, and more preferably 20 to 100 μm.

[0255] <Polarizing plate>

[0256] The present invention includes a polarizing plate (elliptical polarizing plate) that includes the polarizing film or the polarizing film of the present invention and a retardation film. In the polarizing plate of the present invention, the retardation film preferably satisfies the formula (X):

[0257] 100 ≤ Re(550) ≤ 180 (X)

[0258] 〔In the formula, Re(550) represents the in-plane retardation value at a wavelength of 550 nm〕.

[0259] When the in-plane phase difference value represented by the above (X) is provided in the retardation film, it functions as a so-called λ / 4 plate. In the above formula (X), it is preferably 100 nm ≤ Re(550) ≤ 180 nm, and more preferably 120 nm ≤ Re(550) ≤ 160 nm.

[0260] In the polarizing plate of the present invention, the angle formed by the slow axis of the retardation film and the absorption axis of the polarizing film is preferably substantially 45°. It should be noted that in the present invention, "substantially 45°" means 45° ± 5°.

[0261] In addition, the retardation film preferably satisfies the formula (Y):

[0262] Re(450) / Re(550) < 1 (Y)

[0263] 〔In the formula, Re(450) and Re(550) respectively represent the in-plane phase difference values at wavelengths of 450 nm and 550 nm〕.

[0264] The retardation film that satisfies the above formula (Y) has so-called inverse wavelength dispersion and exhibits excellent polarization performance. The value of Re(450) / Re(550) is preferably 0.93 or less, more preferably 0.88 or less, further preferably 0.86 or less, preferably 0.80 or more, and more preferably 0.82 or more.

[0265] The above retardation film may be a stretched film in which a phase difference is imparted by stretching a polymer. From the viewpoint of thinning the polarizing plate, it is preferably a cured product of a polymerizable liquid crystal composition (hereinafter, also referred to as "polymerizable liquid crystal composition (B)") containing a polymerizable liquid crystal compound and is composed of a polymer in the orientation state of the above polymerizable liquid crystal compound. The polymerizable liquid crystal compound (hereinafter, also referred to as "polymerizable liquid crystal compound (B)") that forms the retardation film is a liquid crystal compound having a polymerizable functional group, particularly a photopolymerizable functional group. The so-called photopolymerizable functional group is a group that can participate in a polymerization reaction by active radicals, acids, etc. generated by a photopolymerization initiator. Examples of the photopolymerizable functional group include vinyl, vinyloxy, 1-chloroethylene, isopropenyl, 4-vinylphenyl, acryloyloxy, methacryloyloxy, epoxyethyl, oxetanyl, etc. Among them, acryloyloxy, methacryloyloxy, vinyloxy, epoxyethyl, and oxetanyl are preferred, and acryloyloxy is more preferred. The liquid crystallinity may be thermotropic liquid crystal or lyotropic liquid crystal, and as the phase ordered structure, it may be nematic liquid crystal or smectic liquid crystal. As the polymerizable liquid crystal compound, only one kind may be used, or two or more kinds may be used in combination.

[0266] As the polymeric liquid crystal compound (B), from the viewpoints of ease of film formation and imparting the retardation property represented by the above formula (Y), compounds satisfying all of the following (I) to (IV) can be cited.

[0267] (I) A compound having thermotropic liquid crystallinity;

[0268] (II) Having π electrons in the long axis direction (a) of the polymeric liquid crystal compound.

[0269] (III) Having π electrons in the direction crossing the long axis direction (a) [crossing direction (b)].

[0270] (IV) Denote the total of π electrons present in the long axis direction (a) as N(πa), and the total of molecular weights present in the long axis direction as N(Aa). Define the π electron density in the long axis direction (a) of the polymeric liquid crystal compound by the formula (i):

[0271] D(πa) = N(πa) / N(Aa) (i)

[0272] Denote the total of π electrons present in the crossing direction (b) as N(πb), and the total of molecular weights present in the crossing direction (b) as N(Ab). Define the π electron density in the crossing direction (b) of the polymeric liquid crystal compound by the formula (ii):

[0273] D(πb) = N(πb) / N(Ab) (ii)

[0274] The D(πa) and the D(πb) satisfy the relationship of 0 ≤ [D(πa) / D(πb)] ≤ 1 [that is, the π electron density in the crossing direction (b) is greater than the π electron density in the long axis direction (a)].

[0275] It should be noted that by coating the polymeric liquid crystal compound (B) satisfying all of the above (I) to (IV) on the alignment film formed by rubbing treatment and heating to a temperature above the phase transition temperature, a nematic phase can be formed. For the nematic phase formed by aligning the polymeric liquid crystal compound (B), generally, the alignment is performed such that the long axis directions of the polymeric liquid crystal compounds are parallel to each other, and this long axis direction becomes the alignment direction of the nematic phase.

[0276] The polymeric liquid crystal compound (B) having the above characteristics usually mostly shows inverse wavelength dispersion. As a compound satisfying the characteristics of the above (I) to (IV), for example, the compound represented by the formula (II) can be cited.

[0277] [Chemical formula 28]

[0278]

[0279] The compound represented by the above formula (II) can be used alone or in combination of two or more.

[0280] In formula (II), Ar represents a divalent aromatic group which may have substituents. Herein, the aromatic group refers to a group having a planar ring structure and the number of π electrons in the ring structure being [4n + 2] according to Hückel's rule. Here, n represents an integer. When a ring structure is formed including heteroatoms such as -N=, -S-, etc., it also includes the case where the non-bonding electron pairs on these heteroatoms are included to satisfy Hückel's rule and have aromaticity. At least one or more of nitrogen atom, oxygen atom, and sulfur atom are preferably included in the divalent aromatic group.

[0281] G 1 and G 2 each independently represents a divalent aromatic group or a divalent alicyclic hydrocarbon group. Herein, the hydrogen atoms included in the divalent aromatic group or the divalent alicyclic hydrocarbon group may 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 atoms constituting the divalent aromatic group or the divalent alicyclic hydrocarbon group may be replaced by an oxygen atom, a sulfur atom, or a nitrogen atom.

[0282] L 1 、L 2 、B 1 and B 2 each independently represents a single bond or a divalent linking group.

[0283] k and l each independently represent an integer from 0 to 3, satisfying the relationship 1 ≤ k + l. Here, when 2 ≤ k + l, B 1 and B 2 、G 1 and G 2 may be the same as or different from each other respectively.

[0284] E 1 and E 2 each independently represents an alkylene group having 1 to 17 carbon atoms. Herein, the hydrogen atoms included in the alkylene group may be substituted by a halogen atom, and the -CH 2 - included in the alkylene group may be replaced by -O-, -S-, -Si-. P 1 and P 2 independently of each other represent a polymerizable group or a hydrogen atom, and at least one is a polymerizable group.

[0285] G 1 and G 2Each is independently preferably 1,4-phenylenediyl which may be substituted with at least one substituent selected from the group consisting of a halogen atom and an alkyl group having 1 to 4 carbon atoms, or 1,4-cyclohexanediyl which may be substituted with at least one substituent selected from the group consisting of a halogen atom and an alkyl group having 1 to 4 carbon atoms, more preferably 1,4-phenylenediyl substituted with a methyl group, unsubstituted 1,4-phenylenediyl, or unsubstituted 1,4-trans-cyclohexanediyl, particularly preferably unsubstituted 1,4-phenylenediyl or unsubstituted 1,4-trans-cyclohexanediyl. In addition, it is preferred that there are a plurality of G 1 and G 2 at least one of which is a divalent alicyclic hydrocarbon group. In addition, it is more preferably G 1 or L 2 bonded to G 1 and G 2 at least one of which is a divalent alicyclic hydrocarbon group.

[0286] L 1 and L 2 are each independently preferably a single bond, an alkylene group having 1 to 4 carbon atoms, -O-, -S-, -R a1 OR a2 -, -R a3 COOR a4 -, -R a5 OCOR a6 -, R a7 OC=OOR a8 -, -N=N-, -CR c =CR d -, or -C≡C-. Here, R a1 to R a8 each independently represents a single bond or an alkylene group having 1 to 4 carbon atoms, and R c and R d represent an alkyl group having 1 to 4 carbon atoms or a hydrogen atom. L 1 and L 2 are each independently more preferably a single bond, -OR a2-1 -, -CH 2 -, -CH 2 CH 2 -, -COOR a4-1 -, or OCOR a6-1 -. Here, R a2-1 , R a4-1 , R a6-1 each independently represents a single bond, -CH 2 -, -CH 2 CH 2 -. L 1 and L2 Each is independently further preferably a single bond, -O-, -CH 2 CH 2 -, -COO-, -COOCH 2 CH 2 -, or -OCO-.

[0287] In a preferred embodiment of the present invention, G in formula (II) can be used 1 and G 2 At least one of them is a divalent alicyclic hydrocarbon group, and the divalent alicyclic hydrocarbon group is bonded through a divalent aromatic group Ar which may have a substituent and L which is -COO- 1 and / or L 2 to obtain a polymeric liquid crystal compound.

[0288] B 1 and B 2 Each is independently preferably a single bond, an alkylene group having 1 to 4 carbon atoms, -O-, -S-, -R a9 OR a10 -, -R a11 COOR a12 -, -R a13 OCOR a14 -, or R a15 OC=OOR a16 -. Here, R a9 to R a16 Each independently represents a single bond or an alkylene group having 1 to 4 carbon atoms. B 1 and B 2 Each is independently more preferably a single bond, -OR a10-1 (-), -CH 2 (-), -CH 2 CH 2 (-), -COOR a12 -1 -, or OCOR a14-1 (-). Here, R a10-1 , R a12-1 , R a14-1 Each independently represents a single bond, -CH 2 (-), -CH 2 CH 2 (-), any one of which is selected. B 1 and B 2 Each is independently further preferably a single bond, -O-, -CH 2 CH 2 (-), -COO-, -COOCH 2 CH 2 (-), -OCO-, or -OCOCH 2 CH2 -.

[0289] From the viewpoint of exhibiting inverse wavelength dispersion, k and l are preferably in the range of 2 ≤ k + l ≤ 6, preferably k + l = 4, and more preferably k = 2 and l = 2. When k = 2 and l = 2, a symmetric structure is formed, which is thus further preferred.

[0290] E 1 and E 2 Each is independently preferably an alkylene group having 1 to 17 carbon atoms, and more preferably an alkylene group having 4 to 12 carbon atoms.

[0291] As the polymerizable group represented by P 1 or P 2 Examples include an epoxy group, a vinyl group, a vinyloxy group, a 1-chloro vinyl group, an isopropenyl group, a 4-vinylphenyl group, an acryloyloxy group, a methacryloyloxy group, an oxiranyl group, and an oxetanyl group. Among these, an acryloyloxy group, a methacryloyloxy group, a vinyloxy group, an oxiranyl group, and an oxetanyl group are preferred, and an acryloyloxy group is more preferred.

[0292] Ar preferably has at least one selected from an aromatic hydrocarbon ring which may have a substituent, an aromatic heterocycle which may have a substituent, and an electron-withdrawing group. Examples of the aromatic hydrocarbon ring include a benzene ring, a naphthalene ring, an anthracene ring, etc., and a benzene ring and a naphthalene ring are preferred. Examples of the aromatic heterocycle include a furan ring, a benzofuran ring, a pyrrole ring, an indole ring, a thiophene ring, a benzothiophene ring, a pyridine ring, a pyrazine ring, a pyrimidine ring, a triazole ring, a triazine ring, a pyrroline ring, an imidazole ring, a pyrazole ring, a thiazole ring, a benzothiazole ring, a thiophenothiazole ring, an oxazole ring, a benzoxazole ring, and a phenanthroline ring, etc. Among these, those having a thiazole ring, a benzothiazole ring, or a benzofuran ring are preferred, and those having a benzothiazolyl group are further preferred. When Ar contains a nitrogen atom, the nitrogen atom preferably has π electrons.

[0293] In formula (II), the total number N of π electrons contained in the divalent aromatic group represented by Ar π is preferably 8 or more, more preferably 10 or more, further preferably 14 or more, and particularly preferably 16 or more. In addition, it is preferably 30 or less, more preferably 26 or less, and further preferably 24 or less.

[0294] Examples of the aromatic group represented by Ar include the following groups of formula (Ar-1) to formula (Ar-23).

[0295] [Chemical formula 29]

[0296]

[0297] In Formulae (Ar-1) to (Ar-23), the * symbol represents a connecting portion, and Z 0 , Z 1 and Z 2 each independently represents a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, a cyano group, a nitro group, an alkylsulfinyl group having 1 to 12 carbon atoms, an alkylsulfonyl group having 1 to 12 carbon atoms, a carboxyl group, a fluoroalkyl group having 1 to 12 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alkylthio group having 1 to 12 carbon atoms, an N-alkylamino group having 1 to 12 carbon atoms, an N,N-dialkylamino group having 2 to 12 carbon atoms, an N-alkylsulfamoyl group having 1 to 12 carbon atoms, or an N,N-dialkylsulfamoyl group having 2 to 12 carbon atoms.

[0298] Q 1 and Q 2 each independently represents -CR 2’ R 3’ -, -S-, -NH-, -NR 2’ ]-, -CO- or O-, and R 2’ and R 3’ each independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.

[0299] J 1 and J 2 each independently represents a carbon atom or a nitrogen atom.

[0300] Y 1 , Y 2 and Y 3 each independently represents an optionally substituted aromatic hydrocarbon group or an aromatic heterocyclic group.

[0301] W 1 and W 2 each independently represents a hydrogen atom, a cyano group, a methyl group or a halogen atom, and m represents an integer of 0 to 6.

[0302] As the aromatic hydrocarbon group for Y 1 , Y 2 and Y 3 Examples of the aromatic hydrocarbon group include aromatic hydrocarbon groups having 6 to 20 carbon atoms such as phenyl, naphthyl, anthryl, phenanthryl, biphenyl, etc., preferably phenyl, naphthyl, and more preferably phenyl. Examples of the aromatic heterocyclic group include aromatic heterocyclic groups having 4 to 20 carbon atoms containing at least one hetero atom such as a nitrogen atom, an oxygen atom, a sulfur atom, etc., such as furyl, pyrrolyl, thienyl, pyridyl, thiazolyl, benzothiazolyl, etc., preferably furyl, thienyl, pyridyl, thiazolyl, benzothiazolyl.

[0303] Y 1 and Y 2Each independently may be a substituted polycyclic aromatic hydrocarbon group or a polycyclic aromatic heterocyclic group. The polycyclic aromatic hydrocarbon group refers to a condensed polycyclic aromatic hydrocarbon group or a group derived from an aromatic ring collection. The polycyclic aromatic heterocyclic group refers to a condensed polycyclic aromatic heterocyclic group or a group derived from an aromatic ring collection.

[0304] Z 0 , Z 1 and Z 2 Each of Z is independently preferably a hydrogen atom, a halogen atom, an alkyl group having 1 to 12 carbon atoms, a cyano group, a nitro group, or an alkoxy group having 1 to 12 carbon atoms. 0 More preferably, a hydrogen atom, an alkyl group having 1 to 12 carbon atoms, or a cyano group. 1 and Z 2 More preferred are a hydrogen atom, a fluorine atom, a chlorine atom, a methyl group and a cyano group.

[0305] Q 1 and Q 2 Preferred are -NH-, -S-, -NR 2’ -、-O-,R 2’ A hydrogen atom is preferred, and -S-, -O-, and -NH- are particularly preferred.

[0306] Among the formulae (Ar-1) to (Ar-23), from the viewpoint of molecular stability, the formulae (Ar-6) and (Ar-7) are preferred.

[0307] In the formula (Ar-17) to the formula (Ar-23), Y 1 The nitrogen atom and Z to which it can be bonded 0 Together, they form an aromatic heterocyclic group. Examples of the aromatic heterocyclic group include the aromatic heterocyclic rings described above as the aromatic heterocyclic rings that Ar may have, for example, a pyrrole ring, an imidazole ring, a pyrroline ring, a pyridine ring, a pyrazine ring, a pyrimidine ring, an indole ring, a quinoline ring, an isoquinoline ring, a purine ring, a pyrrolidine ring, etc. The aromatic heterocyclic group may have a substituent. In addition, Y 1 The nitrogen atom and Z to which it can be bonded 0 Together, they form the above-mentioned substituted polycyclic aromatic hydrocarbon group or polycyclic aromatic heterocyclic group. For example, benzofuran ring, benzothiazole ring, benzoxazole ring, etc. can be mentioned. It should be noted that the compound represented by the above formula (II) can be prepared, for example, according to the method described in Japanese Patent Publication No. 2010-31223.

[0308] The content of the polymerizable liquid crystal compound (B) in the polymerizable liquid crystal composition (B) constituting the retardation film is, for example, 70 to 99.5 parts by mass, preferably 80 to 99 parts by mass, and more preferably 90 to 98 parts by mass, based on 100 parts by mass of the solid content of the polymerizable liquid crystal composition (B). When the content is within the above range, the orientation of the retardation film tends to be improved. Here, the solid content refers to the total amount of the components remaining after removing volatile components such as solvents from the polymerizable liquid crystal composition (B).

[0309] The polymerizable liquid crystal composition (B) may contain a polymerization initiator for initiating the polymerization reaction of the polymerizable liquid crystal compound (B). As the polymerization initiator, it can be appropriately selected and used from the polymerization initiators conventionally used in this field. It can be a thermal polymerization initiator or a photo-polymerization initiator. From the aspect of being able to initiate the polymerization reaction at a lower temperature, a photo-polymerization initiator is preferred. Preferred examples include the same substances as those exemplified above as the photo-polymerization initiators that can be used in the polymerizable liquid crystal composition of the present invention. In addition, the polymerizable liquid crystal composition (B) may contain, as needed, photosensitizers, leveling agents, and additives exemplified as the additives contained in the polymerizable liquid crystal composition of the present invention. As the photosensitizers and leveling agents, examples include the same substances as those exemplified above as the photosensitizers and leveling agents that can be used in the polymerizable liquid crystal composition of the present invention.

[0310] The retardation film can be obtained, for example, by the following method: Coating a composition (hereinafter also referred to as "retardation film-forming composition") prepared by adding a solvent to a polymerizable liquid crystal composition (B) containing a polymerizable liquid crystal compound (B) and, as needed, a polymerization initiator, additives, etc., and mixing and stirring it on a substrate or an alignment film, removing the solvent by drying, and curing the polymerizable liquid crystal compound (B) in the obtained coating film by heating and / or active energy rays. As the substrate and / or alignment film that can be used for producing the retardation film, examples include the same substrates and / or alignment films as those exemplified above as the substrates and / or alignment films that can be used in the production of the polarizing film of the present invention.

[0311] Regarding the solvent used in the retardation film-forming composition, the coating method of the retardation film-forming composition, the curing conditions based on active energy rays, etc., examples the same as those that can be adopted in the production method of the polarizing film of the present invention can be cited.

[0312] The thickness of the retardation film can be appropriately selected according to the applicable display device. From the viewpoints of thinning and flexibility, etc., it is preferably 0.1 to 10 μm, more preferably 1 to 5 μm, and further preferably 1 to 3 μm.

[0313] The polarizing plate of the present invention comprises the polarizing film or polarizing thin film of the present invention and a retardation film, and preferably comprises a substrate, an alignment film (especially a photo-alignment film), the polarizing film of the present invention, and a retardation film. In addition, other layers (such as a protective film, an adhesive layer, etc.) other than these may also be included. In the polarizing plate of the present invention, the polarizing film or polarizing thin film of the present invention and the retardation film may be adhered via an adhesive layer or an adhesive agent layer, or a retardation film may be directly formed on the polarizing film or polarizing thin film of the present invention by directly coating a composition for forming a retardation film on the polarizing film or polarizing thin film of the present invention.

[0314] From the viewpoints of the bendability and visual recognition of the display device, the thickness of the polarizing plate of the present invention is preferably 10 to 300 μm, more preferably 20 to 200 μm, and still more preferably 25 to 100 μm.

[0315] <Display device>

[0316] The present invention includes a display device comprising the polarizing film or polarizing thin film of the present invention, or the polarizing plate of the present invention. The display device of the present invention can be obtained, for example, by adhering the polarizing film, polarizing thin film or polarizing plate of the present invention to the surface of the display device via an adhesive layer. A display device refers to a device having a display mechanism and includes a light-emitting element or a light-emitting device as a light source. Examples of the display device include a liquid crystal display device, an organic electroluminescence (EL) display device, an inorganic electroluminescence (EL) display device, a touch panel display device, an electron emission display device (field emission display device (FED), surface conduction field emission display device (SED)), an electronic paper (a display device using electronic ink, an electrophoretic element), a plasma display device, a projection display device (such as a grating light valve (GLV) display device, a display device having a digital micromirror device (DMD), etc.), and a piezoelectric ceramic display. The liquid crystal display device includes all of a transmissive liquid crystal display device, a transflective liquid crystal display device, a reflective liquid crystal display device, a direct-view liquid crystal display device, and a projection liquid crystal display device. These display devices may be a display device for displaying a two-dimensional image or a stereoscopic display device for displaying a three-dimensional image. In particular, as the display device of the present invention, an organic EL display device and a touch panel display device are preferred, and an organic EL display device is particularly preferred.

[0317] Examples

[0318] <Preparation of a composition for forming a polarizing film>

[0319] The following components were mixed and stirred at 80 °C for 1 hour to obtain a composition (1) for forming a polarizing film. The dichroic pigment used was the azo pigment described in the examples of JP-A-2013-101328.

[0320] · Polymerizable liquid crystal compound:

[0321] [Chemical formula 30]

[0322]

[0323] [Chemical formula 31]

[0324]

[0325] · Dichroic pigment:

[0326] Azo pigment;

[0327] [Chemical formula 32]

[0328]

[0329] [Chemical formula 33]

[0330]

[0331] [Chemical formula 34]

[0332]

[0333] · Levelling agent:

[0334] 1.2 parts of polyacrylate compound (BYK-361N; manufactured by BYK-Chemie)

[0335] · Solvent:

[0336] 400 parts of o-xylene

[0337] In the above-described polarizing film-forming composition (1), the compounds described in Table 1 as photoinitiators are mixed in the amounts shown in Table 2. Other than this, the same operations as those for the polarizing film-forming composition (1) are carried out to obtain polarizing film-forming compositions (2) to (13). The addition amounts of the photoinitiators in Table 2 represent the amounts relative to 100 parts by mass of the polymerizable liquid crystal compound in the polarizing film-forming composition (1).

[0338] <Structure of photoinitiator>

[0339] The photoinitiators used in the examples and comparative examples are as follows.

[0340] [Table 1]

[0341]

[0342] [Table 2]

[0343]

[0344] <Measurement of the Liquid Crystal Phase Transition Temperature Change T1 - T2>

[0345] (1) Formation of the Alignment Film

[0346] Using the spin - coating method, a 2% by mass aqueous solution of polyvinyl alcohol (fully saponified polyvinyl alcohol 1000, manufactured by Wako Pure Chemical Industries, Ltd.) (alignment polymer composition / alignment film - forming composition) was coated on a glass substrate. After drying, a film with a thickness of 100 nm was formed. Next, by performing a rubbing treatment on the surface of the obtained film, an alignment film was formed. The rubbing treatment was carried out using a semi - automatic rubbing device (trade name: LQ - 008 type, manufactured by Shoyo Kogyo Co., Ltd.) with a cloth (trade name: YA - 20 - RW, manufactured by Yoshikawa Chemical Industry Co., Ltd.) under the conditions of a press - in amount of 0.15 mm, a rotation speed of 500 rpm, and a speed of 16.7 mm / s.

[0347] (2) Measurement of T1

[0348] 90 parts of (A - 6), 10 parts of (A - 7), and 400 parts of o - xylene as a polymerizable liquid crystal compound were stirred at 80 °C for 1 hour to obtain a uniformly mixed composition. The obtained composition was coated on the aforementioned glass with an alignment film by the spin - coating method and dried by heating on a hot plate at 130 °C for 3 minutes to remove o - xylene as a solvent. Then, it was rapidly cooled to room temperature to obtain a dry film of the polymerizable liquid crystal compound. The dry film was heated again to 130 °C on a hot plate and then cooled at a rate of 5 °C / min to 23 °C, and observed with a polarizing microscope. Thus, the phase transition temperature was measured. As a result, it was confirmed that it changed to the nematic liquid crystal phase at 113.8 °C, to the smectic A phase at 109.7 °C, and to the smectic B phase at 92.8 °C, and maintained the smectic B phase until it reached 23 °C. In the above process, the liquid crystal phase presented on the lowest temperature side was the smectic B phase. Therefore, T1 was defined as the phase transition temperature of 92.8 °C for the transition to the smectic B phase.

[0349] (3) Measurement of T2

[0350] To the above - mentioned mixed composition, photoinitiators A - F, each 5 parts by mass relative to 100 parts by mass of the polymerizable liquid crystal compound, were added. Otherwise, using exactly the same method as the measurement of T1 in (2) above, a dry film formed from a mixture of a photoinitiator and a polymerizable liquid crystal compound was obtained. Using the same method as the measurement of T1 in (2) above, the phase transition temperature was measured. As a result, in all the mixtures, the liquid crystal phase presented on the lowest temperature side was the smectic B phase. The phase transition temperature (T2) for the transition to the liquid crystal phase presented on the lowest temperature side when each photoinitiator was contained is shown in Table 3.

[0351] [Table 3]

[0352]

[0353] Example 1

[0354] (1) Preparation of Photo - aligned Film on Substrate

[0355] (i) Preparation of Composition for Forming Photo - aligned Film

[0356] The following components described in JP - A - 2013 - 033249 were mixed and the resulting mixture was stirred at 80°C for 1 hour to obtain a composition for forming a photo - aligned film.

[0357] · Photo - aligning polymer:

[0358] [Chemical formula 35]

[0359]

[0360] · Solvent:

[0361] 98 parts of o - xylene

[0362] (ii) Formation of Photo - aligned Film

[0363] As the substrate, a triacetyl cellulose film (KC8UX2M, manufactured by Konica Minolta, Inc.) was used. After corona - treating the film surface, the above - described composition for forming a photo - aligned film was coated and dried at 120°C to obtain a dried film. Polarized UV light was irradiated onto this dried film to form a photo - aligned film, and a film with a photo - aligned film was obtained. The polarized UV light treatment was carried out using a UV irradiation device (SPOT CURE SP - 7; manufactured by Ushio Inc.) under the condition that the intensity measured at a wavelength of 365 nm was 100 mJ.

[0364] (2) Preparation of Polarizing Film

[0365] On the film with a photo - aligned film obtained by the above - described operation, a composition for forming a polarizing film (2) was coated by a bar coating method (#9, 30 mm / s), and heated and dried in a drying oven at 120°C for 1 minute to transform the polymerizable liquid crystal compound into a liquid phase. Then, it was cooled to room temperature to transform the polymerizable liquid crystal compound into a smectic liquid crystal state. Next, using a UV irradiation device (SPOT CURE SP - 7; manufactured by Ushio Inc.), the layer formed from the composition for forming a polarizing film was irradiated with an exposure dose of 1000 mJ / cm 2Ultraviolet rays (365 nm reference) are used to polymerize the polymerizable liquid crystal compound contained in the dried film while maintaining the smectic liquid crystal state of the polymerizable liquid crystal compound, and a polarizing film is formed from the dried film. The film thickness of the polarizing film at this time is measured using a laser microscope (OLS3000 manufactured by Olympus Corporation), and the result is 2.3 μm. The product obtained as described above is a polarizing plate including a polarizing film and a substrate.

[0366] Regarding this polarizing film, an X-ray diffractometer X’Pert PRO MPD (manufactured by Spectris Co., Ltd.) is used to irradiate X-rays from the absorption axis direction of the polarizing film and perform X-ray diffraction measurement. As a result, a sharp diffraction peak (Bragg peak) with a full width at half maximum (FWHM) of approximately 0.17° is obtained near 2θ = 20.2°. In addition, X-rays are irradiated from the transmission axis direction of the polarizing film, and X-ray diffraction measurement is similarly performed. As a result, the same sharp diffraction peak (Bragg peak) is obtained, and the ordered period (d) calculated from its peak position is approximately It is confirmed that a structure reflecting a higher-order smectic phase is formed.

[0367] (3) Fabrication of the polarizing film laminate

[0368] Furthermore, corona treatment is performed on the surface of the polarizing film of the polarizing plate obtained by the same operation as above. Then, on the surface subjected to corona treatment, an aqueous solution (viscosity: 92 cP) prepared by adding 7 parts of carboxyl-modified polyvinyl alcohol (“Kuraray POVAL KL318” manufactured by Kuraray Co., Ltd.) and 3.5 parts of a water-soluble polyamide epoxy resin (“Sumirez Resin 650” obtained from Sumika Chemtex Co., Ltd., an aqueous solution with a solid content concentration of 30% by mass) to 100 parts of water is coated using a wire bar coater (#30). Drying is performed at 80°C for 5 minutes, whereby the aforementioned aqueous solution is dried to form a protective layer, and a polarizing plate with a protective layer is manufactured. Furthermore, on the protective layer, a glass (Eagle XG manufactured by Corning Inc.) is adhered via an adhesive layer formed of a pressure-sensitive adhesive (manufactured by Lintec Corporation, film thickness: 25 μm), and the polarizing film laminate of Example 1 is obtained.

[0369] Instead of the polarizing film-forming composition (2), the polarizing film-forming compositions (3) to (13) shown in Table 2 are used respectively, and the polarizing film laminates of Examples 2 to 8 and Comparative Examples 1 to 4 are obtained by the same method.

[0370] <Measurement of absorbance in the absorption axis direction / absorbance in the transmission axis direction>

[0371] In the following manner, the absorbance in the absorption axis direction (MD) and the absorbance in the transmission axis direction (TD) of the dried film (before polymerization) of the polarizing film-forming composition and the polarizing film laminate (after polymerization) before ultraviolet irradiation were measured respectively and are shown in Table 4. Using a device in which a polarizer holder is installed on a spectrophotometer (UV-3150 manufactured by Shimadzu Corporation), the absorbance in the absorption axis direction (MD) and the absorbance in the transmission axis direction (TD) in the wavelength range of 550 nm were measured by the double beam method. A net that blocks 50% of the light quantity was installed on the reference side of the polarizer holder. The dichroic ratio DR was calculated based on the following (Equation 2).

[0372] DR = MD / TD (Equation 2)

[0373] [Table 4]

[0374]

[0375] Regarding the polarizing films (Examples 1 to 8) made from the polymerizable liquid crystal composition (polarizing film-forming composition) of the present invention, it was confirmed that the change in the dichroic ratio DR before and after polymerization was small, and in addition, the dichroic ratio DR after polymerization was excellent.

Claims

1. A polymerizable liquid crystal composition comprising a polymerizable liquid crystal compound, a dichroic dye, and a photopolymerization initiator, wherein the dichroic dye is an azo dye, the polymerizable liquid crystal compound has at least one polymerizable group and exhibits smectic liquid crystallinity, the photopolymerization initiator is an oxime ester compound, the photopolymerization initiator satisfies formula (1) in relation to the polymerizable liquid crystal compound: 0 °C ≤ T1 - T2 ≤ 12.0 °C (1) In formula (1), T1 is the phase transition temperature at which the polymerizable liquid crystal compound is heated to 130 °C in the atmosphere and then cooled to 23 °C at a rate of 5 °C / min while measuring the phase transition temperature, and is the phase transition temperature at which the liquid crystal phase presented on the lowest temperature side is transformed; T2 is the phase transition temperature at which a mixture formed by 100 parts by mass of the polymerizable liquid crystal compound and 5 parts by mass of the photopolymerization initiator is heated to 130 °C in the atmosphere and then cooled to 23 °C at a rate of 5 °C / min while measuring the phase transition temperature, and is the phase transition temperature at which the liquid crystal phase presented on the lowest temperature side is transformed.

2. The polymerizable liquid crystal composition according to claim 1, further comprising a solvent.

3. The polymerizable liquid crystal composition according to claim 1 or 2, wherein the polymerizable group possessed by the polymerizable liquid crystal compound is acryloyloxy or methacryloyloxy.

4. The polymerizable liquid crystal composition according to any one of claims 1 to 3, wherein the weight average molecular weight of the photopolymerization initiator is 500 or more and 2000 or less.

5. The polymerizable liquid crystal composition according to any one of claims 1 to 4, wherein 1 to 10 parts by mass of the photopolymerization initiator is contained relative to 100 parts by mass of the polymerizable liquid crystal compound.

6. A polarizing film which is a cured product of the polymerizable liquid crystal composition according to any one of claims 1 to 5 and shows a Bragg peak in X-ray diffraction measurement.

7. The polarizing film according to claim 6, having a thickness of 0.1 to 5 μm.

8. A polarizing thin film comprising the polarizing film according to claim 6 or 7 and a transparent film.

9. A polarizing plate comprising: the polarizing film according to claim 6 or 7 or the polarizing thin film according to claim 8; and a retardation film.

10. The polarizing plate according to claim 9, wherein the retardation film satisfies formula (X): 100 ≤ Re(550) ≤ 180 (X) In formula (X), Re(550) represents the in-plane retardation value at a wavelength of 550 nm, and the angle formed by the slow axis of the retardation film and the absorption axis of the polarizing film is substantially 45°.

11. The polarizing plate according to claim 9 or 10, wherein the retardation film satisfies formula (Y): Re(450) / Re(550) < 1 (Y) In formula (Y), Re(450) and Re(550) respectively represent the in-plane retardation values at wavelengths of 450 nm and 550 nm.

12. The polarizing plate according to any one of claims 9 to 11, wherein the retardation film is composed of a polymer in an oriented state of a polymerizable liquid crystal compound.

13. A display device comprising the polarizing thin film according to claim 8, or the polarizing plate according to any one of claims 9 to 12.

14. A method for manufacturing a polarizing film, comprising the following steps: A step of forming a coating film of the polymerizable liquid crystal composition according to any one of claims 1 to 5; A step of removing a solvent from the coating film; A step of heating to a temperature above the phase transition temperature of the polymerizable liquid crystal compound to a liquid phase and then cooling to cause the polymerizable liquid crystal compound to phase transition to a smectic phase; And, A step of polymerizing the polymerizable liquid crystal compound while maintaining the smectic phase state.

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