Polarizing film and method for producing same

Abstract

The invention relates to a polarizing film and a method for manufacturing the same. The polarizing film has a liquid crystal layer. The liquid crystal layer contains a liquid crystal compound, and has at least two types of regions which are divided according to the value of the visibility correction polarization degree. The contents of dichroic pigments in the at least two regions are different from each other.

Description

[0001] This application is a divisional application of Chinese invention patent application No. 201880069704.0 (PCT application number PCT / JP2018 / 038525), whose application date is October 16, 2018 and whose invention name is “Polarizing film and its manufacturing method”. Technical Field

[0002] The present invention relates to a polarizing film and a method for producing the same, and in particular to a polarizing film having a layer containing a liquid crystal compound and a dichroic dye and a method for producing the same. Background Art

[0003] Organic EL displays using organic light-emitting diodes (OLEDs) are not only lighter and thinner than liquid crystal displays, but also offer high image quality, such as a wide viewing angle, fast response speed, and high contrast. Consequently, they are being used in a variety of fields, including smartphones, televisions, and digital cameras. To reduce the loss of visibility caused by reflection of external light, organic EL displays are known to use circularly polarizing plates and other methods to improve anti-reflection performance.

[0004] As polarizing films that can be used for such circularly polarizing plates, Japanese Patent Application Laid-Open No. 2015-206852 (Patent Document 1) and Japanese Patent Application Laid-Open No. 2015-212823 (Patent Document 2) describe patterned polarizing films in which a patterned liquid crystal cured film is laminated on a substrate.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Laid-Open No. 2015-206852

[0008] Patent Document 2: Japanese Patent Application Laid-Open No. 2015-212823 Summary of the Invention

[0009] Problems to be solved by the invention

[0010] An object of the present invention is to provide a novel polarizing film having at least two regions having different values ​​of visibility-corrected polarization degrees, and a method for producing the same.

[0011] Means for solving problems

[0012] The present invention provides the following polarizing film and a method for producing the same.

[0013] [1] A polarizing film having a liquid crystal layer,

[0014] The liquid crystal layer contains a liquid crystal compound and has at least two regions that are distinguished according to the value of the visibility-corrected polarization degree.

[0015] The at least two types of regions have different contents of the dichroic dye.

[0016] [2] The polarizing film as described in [1], further comprising:

[0017] a substrate layer, and

[0018] an orientation layer laminated on at least one side of the substrate layer,

[0019] The liquid crystal layer is stacked on the alignment layer.

[0020] [3] The polarizing film according to [2], wherein the alignment layer contains a photo-alignment polymer.

[0021] [4] The polarizing film according to any one of [1] to [3], wherein the liquid crystal compound comprises a polymerizable liquid crystal compound.

[0022] [5] The polarizing film according to any one of [1] to [4], wherein the liquid crystal layer comprises a first region containing a dichroic dye and a second region having a lower content of the dichroic dye than the first region.

[0023] The visibility correction polarization degree of the first region is 90% or more.

[0024] The visibility-corrected polarization degree of the second region is 10% or less.

[0025] [6] The polarizing film according to any one of [1] to [5], wherein the liquid crystal layer comprises a first region containing a dichroic dye and a second region having a lower content of the dichroic dye than the first region.

[0026] The visibility correction single transmittance of the first region is 35% or more.

[0027] The visibility correction single unit transmittance of the second region is 80% or more.

[0028] [7] The polarizing film according to any one of [5] and [6], wherein the second region has a circular, elliptical, oblong, or polygonal shape when viewed from above.

[0029] The diameter of the second region when it is circular is less than 5 cm,

[0030] When the second region is elliptical or oblong, its major diameter is 5 cm or less.

[0031] When the second region is a polygon, the diameter of an imaginary circle drawn so as to inscribe the polygon is 5 cm or less.

[0032] [8] The polarizing film according to any one of [5] to [7], wherein the first region shows a Bragg peak in X-ray diffraction measurement.

[0033] [9] The polarizing film according to any one of [1] to [8], further comprising a substrate layer.

[0034] The base material layer functions as a quarter-wave plate.

[0035]

[10] The polarizing film according to any one of [1] to [9], wherein the length of the polarizing film is 10 m or longer.

[0036]

[11] A circularly polarizing plate comprising a laminate of the polarizing film according to any one of [1] to [8] and

[10] and a phase difference layer having a quarter wavelength plate function.

[0037]

[12] A method for producing a polarizing film, comprising the following steps:

[0038] a preparation step of preparing a laminated film having a polarizing layer containing a liquid crystal compound and a dichroic dye on at least one side of a substrate layer; and

[0039] The liquid material contact step reduces the content of the dichroic dye in a portion of the polarizing layer by contacting a portion of the polarizing layer of the laminated film with a liquid material capable of reducing the content of the dichroic dye in the polarizing layer.

[0040]

[13] The method for producing a polarizing film according to

[12] , wherein the liquid material contact step comprises the following steps:

[0041] a protective layer laminating step of laminating a protective layer having a covered region for covering the polarizing layer and an exposed region for exposing the polarizing layer on the polarizing layer of the laminated film prepared in the preparing step, thereby obtaining a laminated film with a protective layer;

[0042] a decolorization step of bringing the laminated film with the protective layer into contact with a liquid capable of reducing the content of the dichroic pigment in the polarizing layer, thereby obtaining a decolorized laminated film having a reduced content of the dichroic pigment in a portion of the polarizing layer; and

[0043] The peeling step is to peel the protective layer from the decolorized laminated film.

[0044]

[14] The method for producing a polarizing film according to

[13] , wherein the exposed area in the protective layer has a circular, elliptical, oblong or polygonal shape when viewed from above.

[0045] The diameter of the exposed area in the case of a circle is 5 cm or less.

[0046] When the exposed area is elliptical or oblong, the major diameter is 5 cm or less.

[0047] When the exposed area is a polygon, the diameter of an imaginary circle drawn so as to inscribe the polygon is 5 cm or less.

[0048]

[15] The method for producing a polarizing film according to any one of

[12] to

[14] , wherein the preparation step comprises the following steps:

[0049] an alignment layer forming step of coating an alignment layer forming composition on one side of the substrate layer to form an alignment layer; and

[0050] The polarizing layer forming step comprises applying a polarizing layer forming composition containing the liquid crystal compound and the dichroic dye on the surface of the substrate layer on which the alignment layer is formed, thereby forming the polarizing layer.

[0051]

[16] The method for producing a polarizing film according to

[15] , wherein the composition for forming an alignment layer contains a photo-alignment polymer,

[0052] In the alignment layer forming step, the alignment layer is formed by irradiating the alignment layer coating layer formed by applying the alignment layer forming composition with polarized light.

[0053]

[17] The method for producing a polarizing film according to

[15] or

[16] , wherein the liquid crystal compound is a polymerizable liquid crystal compound.

[0054] In the polarizing layer forming step, the polarizing layer is formed by irradiating the polarizing layer coating layer formed by applying the polarizing layer forming composition with active energy rays.

[0055]

[18] The method for producing a polarizing film according to any one of

[12] to

[17] , wherein the length of the polarizing film is 10 m or longer.

[0056]

[19] A method for manufacturing a circularly polarizing plate, comprising the following steps:

[0057] The retardation layer lamination step is to laminate the polarizing film produced by the method for producing a polarizing film described in any one of

[12] to

[18] and the retardation layer having a quarter wavelength plate function.

[0058]

[20] The method for producing a circularly polarizing plate according to

[19] , wherein the polarizing film is a long strip of polarizing film having a length of 10 m or more.

[0059] The aforementioned phase difference layer is a strip-shaped phase difference layer with a length of more than 10m.

[0060] In the phase difference layer lamination step, the long strip polarizing film and the long strip phase difference layer are laminated to form a long strip laminate.

[0061] The manufacturing method further comprises a cutting step of cutting the long-length laminate into individual pieces.

[0062] Effects of the Invention

[0063] According to the present invention, a polarizing film having at least two regions having different values ​​of visibility-corrected polarization degree and a method for producing the same can be provided. BRIEF DESCRIPTION OF THE DRAWINGS

[0064] [ Figure 1 ](a) is a schematic top view showing an example of the polarizing film of the present invention, and (b) is a XX cross-sectional view of (a).

[0065] [ Figure 2 ](a) to (c) are schematic cross-sectional views showing an example of the circularly polarizing plate of the present invention.

[0066] [ Figure 3 ] (a) to (d) are schematic cross-sectional views showing an example of the layer structure obtained in each step of the production process of the polarizing film of the present invention.

[0067] [ Figure 4 ] is a schematic cross-sectional view showing an example of a liquid material contact step in the method for manufacturing a polarizing film of the present invention. DETAILED DESCRIPTION

[0068] Hereinafter, preferred embodiments of the polarizing film and the method for producing the same of the present invention will be described with reference to the accompanying drawings. It should be noted that the scope of the present invention is not limited to the embodiments described herein, and various modifications can be made without impairing the gist of the present invention.

[0069] <Polarizing film>

[0070] Figure 1 (a) is a schematic plan view showing an example of the polarizing film of the present invention, Figure 1 (b) Figure 1(a) XX cross-sectional view. The polarizing film 1 of this embodiment is a film having light absorption anisotropy and includes a liquid crystal layer 11 containing a liquid crystal compound. The liquid crystal layer 11 has at least two regions distinguished by the value of the visibility-corrected polarization degree (Py), and the at least two regions have different dichroic pigment contents. The polarizing film 1 is a film having the liquid crystal layer 11, but may further include a substrate layer 13, an orientation layer 12, and other layers. Figure 1 In the polarizing film 1 shown in (b), an example is shown in which the alignment layer 12 and the liquid crystal layer 11 are provided on one side of the substrate layer 13. However, the alignment layer and the liquid crystal layer may be provided on both sides of the substrate layer 13. The structures of the liquid crystal layers provided on both sides of the substrate layer 13 may be the same or different.

[0071] The polarizing film 1 can be a long strip of polarizing film having a length of 10 m or more. In this case, the polarizing film 1 can be formed into a roll. The polarizing film can be continuously unwound from the roll, laminated with the phase difference layer described later, and cut into individual sheets. The length of the long strip of polarizing film formed into a roll is not particularly limited, as long as it is 10 m or more, and can be, for example, 10,000 m or less.

[0072] (Liquid crystal layer)

[0073] The liquid crystal layer 11 contains a liquid crystal compound and has regions containing the liquid crystal compound and a dichroic dye. When the polarizing film 1 has polarization properties in the plane of the polarizing film 1, the liquid crystal layer 11 preferably has regions where the dichroic dye and the liquid crystal compound are aligned horizontally with respect to the plane of the polarizing film 1. Furthermore, when the polarizing film 1 has polarization properties in the thickness direction of the polarizing film 1, the liquid crystal layer 11 preferably has regions where the dichroic dye and the liquid crystal compound are aligned horizontally with respect to the plane of the polarizing film 1.

[0074] For the area in the liquid crystal layer 11 that contains a dichroic dye and a liquid crystal compound and that is horizontally oriented relative to the surface of the polarizing film 1, the ratio of the absorbance A1(λ) in the horizontal direction of the liquid crystal orientation relative to light of wavelength λnm to the absorbance A2(λ) in the vertical direction within the liquid crystal orientation plane, i.e., the dichroic ratio (=A1(λ) / A2(λ)) is preferably 7 or more, more preferably 20 or more, and even more preferably 30 or more. The higher the value, the more polarization characteristics with excellent absorption selectivity. Although it also depends on the type of dichroic dye, when the liquid crystal layer 11 is a nematic liquid crystal phase, the above ratio is about 5 to 10. It should be noted that when the liquid crystal layer 11 is a nematic liquid crystal phase and a smectic liquid crystal phase described later, the liquid crystal compound and the dichroic dye do not undergo phase separation, which can be confirmed, for example, by surface observation based on various microscopes and scattering measurement based on a haze meter.

[0075] like Figure 1 As shown in (a) and (b), the liquid crystal layer 11 includes a first region 11a and a second region 11b that are differentiated by the visibility-corrected polarization degree (Py) and differentiated by the content of the dichroic dye. Figure 1 In the polarizing film 1 shown in (a), an example is shown in which two regions each have one visibility correction polarization degree (Py) and one dichroic pigment content, but the first region and the second region can each have more than two, and further, there can be three or more regions with different dichroic pigment contents.

[0076] Figure 1 The first region 11a of the polarizing film 1 shown in (a) contains a liquid crystal compound and a dichroic dye. The second region 11b contains a liquid crystal compound, but may or may not contain a dichroic dye. If a dichroic dye is contained, its content is preferably lower than the content of the dichroic dye in the first region 11a.

[0077] The content of the dichroic dye in the liquid crystal layer 11 can be determined by measuring the maximum absorption wavelength (λ MAX ) was determined by the absorbance at .

[0078] The first region 11a preferably has high polarization properties. For example, the visibility-corrected polarization degree (Py) can be 90% or higher, preferably 92% or higher, more preferably 95% or higher, and typically 100% or lower. Furthermore, the first region 11a can have a visibility-corrected single-unit transmittance (Ty) of, for example, 35% or higher, preferably 40% or higher, more preferably 44% or higher, and typically less than 50%.

[0079] The second region 11b is preferably a low-polarization region having a visibility-corrected polarization degree (Py) lower than that of the first region 11a. The visibility-corrected polarization degree (Py) of the second region 11b can be, for example, 10% or less, preferably 5% or less, more preferably 1% or less, and can be 0%. Furthermore, the second region 11b preferably has a higher visibility-corrected single transmittance (Ty) than the visibility-corrected single transmittance (Ty) of the first region 11a. The visibility-corrected single transmittance (Ty) of the second region 11b can be, for example, 80% or more, preferably 85% or more, more preferably 88% or more, and typically 98% or less.

[0080] The visibility correction polarization degree (Py) and visibility correction single transmittance (Ty) in this specification can be calculated based on the polarization degree and single transmittance measured using a spectrophotometer. For example, a device formed by setting a folder with a polarizer on a spectrophotometer can be used in the range of 380nm to 780nm as a wavelength of visible light, and using a double beam method, the transmittance (T1) in the transmission axis direction (orientation perpendicular direction) and the transmittance (T2) in the absorption axis direction (orientation in the same direction) can be measured. For the polarization degree and single transmittance in the visible light range, the following formulas (Formula 1) and (Formula 2) are used to calculate the polarization degree and single transmittance at each wavelength, and then, using the 2-degree field of view (C light source) of JIS Z 8701, visibility correction is performed, thereby being able to be calculated in the form of visibility correction single transmittance (Ty) and visibility correction polarization degree (Py).

[0081] Polarization degree [%]={(T1-T2) / (T1+T2)}×100 (Formula 1)

[0082] Single body transmittance [%] = (T1 + T2) / 2 (Formula 2)

[0083] The occupied area of ​​the first region 11a and the occupied area of ​​the second region 11b can be appropriately selected according to the characteristics required of the polarizing film 1. The total ratio of the occupied areas of the first region 11a and the second region 11b relative to the surface area of ​​the polarizing film 1 is preferably 90% or more, more preferably 95% or more, and further preferably 99% or more. In addition, the occupied area of ​​the first region 11a is preferably 50% or more, more preferably 70% or more, and further preferably 80% or more relative to the total area of ​​the occupied areas of the first region 11a and the occupied areas of the second region 11b. For example, Figure 1 As shown in (a), the occupied area of ​​the second region 11b is smaller than the occupied area of ​​the first region 11a, and the first region 11a can be provided so as to surround the second region 11b. Figure 1 In the polarizing film 1 shown in (a), the first region 11a is provided so as to surround a circular second region 11b. However, a plurality of second regions 11b may be provided independently.

[0084] The shape of the first region 11a and the shape of the second region 11b are not particularly limited. For example, Figure 1 As shown in (a), when the first area 11a is set in a manner surrounding the second area 11b, the top view shape of the second area 11b can be formed into any shape such as a circle; an ellipse; an oblong; a polygon such as a triangle, square, rectangle, or rhombus; a text shape; or a combination thereof.

[0085] The top view shape of the second area 11b is preferably circular, elliptical, oblong, or polygonal. When the second area 11b is circular, its diameter is preferably 5 cm or less, more preferably 3 cm or less, and further preferably 2 cm or less. When the second area 11b is elliptical or oblong, its major axis is preferably 5 cm or less, more preferably 3 cm or less, and further preferably 2 cm or less. When the second area 11b is polygonal, the diameter of an imaginary circle drawn in such a manner as to inscribe the polygon is preferably 5 cm or less, more preferably 3 cm or less, and further preferably 2 cm or less. The second area 11b of the above-mentioned shape can be suitably used as an area corresponding to the lens position of a camera provided in a smartphone, tablet computer, etc. In addition, at this time, by making the second area 11b a region with a visibility-corrected polarization degree (Py) of less than 10% and a visibility-corrected single transmittance (Ty) of more than 80%, the coloring of the second area 11b can be reduced, and excellent transparency can be obtained, thereby improving the performance of the camera.

[0086] Alternatively, the first region 11a and the second region 11b may each be arranged so as to have a linear, strip-like, or wavy shape in plan view. In this case, a plurality of first regions 11a and a plurality of second regions 11b may be arranged alternately. In this case, the width of each of the first region 11a and the second region 11b is preferably 1 μm to 10 mm, more preferably 1 μm to 1 mm, and even more preferably 1 μm to 100 μm.

[0087] It should be noted that, when the polarizing film is a long strip of polarizing film, the long strip of polarizing film can usually be cut into a specified size according to the purpose of the polarizing film, and therefore, it is preferred to set the configuration of the first region 11a and the second region 11b in the long strip of polarizing film in such a way that the first region 11a and the second region 11b are formed at specified positions of the polarizing film after cutting. For example, when the polarizing film after cutting is Figure 1 In the case of the polarizing film 1 shown in (a), it is preferable that a plurality of second regions 11 b are provided at predetermined intervals in the longitudinal direction and / or the width direction of the long polarizing film.

[0088] The thickness of the first region 11a in the liquid crystal layer 11 is preferably 0.5 μm or greater, more preferably 1 μm or greater, and preferably 5 μm or less, more preferably 3 μm or less. Furthermore, the thickness of the second region 11b in the liquid crystal layer 11 is preferably the same as that of the first region 11a, preferably 0.5 μm or greater, more preferably 1 μm or greater, and preferably 5 μm or less, more preferably 3 μm or less. The thickness of the liquid crystal layer 11 can be measured using an interferometer, a laser microscope, a stylus-type film thickness gauge, or the like.

[0089] The thickness of the second region 11b can be smaller than the thickness of the first region 11a. The difference between the thickness of the first region 11a and the thickness of the second region 11b is preferably 2 μm or less, more preferably 1 μm or less, and even more preferably 0.5 μm or less. By making the thickness of the first region 11a and the second region 11b of the liquid crystal layer 11 equal, the height difference between the first region 11a and the second region 11b is reduced. When the phase difference layer and other layers (surface protection layer, etc.) described later are stacked on the liquid crystal layer 11, it is possible to suppress the entrapment of bubbles, the generation of wrinkles, and other undesirable conditions. In addition, when the polarizing film 1 having the liquid crystal layer 11 is wound into a roll, it is also possible to suppress undesirable conditions such as the formation of roll marks.

[0090] (Liquid Crystal Compound)

[0091] As the liquid crystal compound contained in the liquid crystal layer 11, known liquid crystal compounds can be used. The type of liquid crystal compound is not particularly limited, and rod-shaped liquid crystal compounds, disc-shaped liquid crystal compounds, and mixtures thereof can be used. In addition, the liquid crystal compound can be a polymeric liquid crystal compound, a polymerizable liquid crystal compound, or a mixture thereof.

[0092] As the liquid crystal compound, a polymerizable liquid crystal compound is preferably used. By using a polymerizable liquid crystal compound, the hue of the polarizing film can be arbitrarily controlled and the polarizing film can be significantly thinned. Furthermore, the polarizing film can be manufactured without undergoing a stretching process, thus enabling the production of a non-stretchable polarizing film without thermal stretching relaxation.

[0093] The so-called polymerizable liquid crystal compound refers to a compound having a polymerizable group and having liquid crystal properties. A polymerizable group refers to a group that participates in the polymerization reaction, preferably a photopolymerizable group. The so-called photopolymerizable group here refers to a group that can participate in the polymerization reaction through active free radicals, acids, etc. generated by the photopolymerization initiator described later. As polymerizable groups, vinyl, vinyloxy, 1-chlorovinyl, isopropenyl, 4-vinylphenyl, acryloyloxy, methacryloyloxy, oxirane, oxetanyl, etc. can be mentioned. Among them, acryloyloxy, methacryloyloxy, vinyloxy, oxirane or oxetanyl are preferred, and acryloyloxy is more preferred. The liquid crystal can be a thermotropic liquid crystal or a lyotropic liquid crystal. When mixed with a dichroic pigment as in the liquid crystal layer of the present embodiment, a thermotropic liquid crystal is preferably used.

[0094] When the polymerizable liquid crystal compound is a thermotropic liquid crystal, it can be a thermotropic liquid crystal compound that exhibits a nematic liquid crystal phase, or it can be a thermotropic liquid crystal compound that exhibits a smectic liquid crystal phase. When the liquid crystal layer 11 exhibits a polarizing function as a polymer film obtained by a polymerization reaction, the liquid crystal state presented by the polymerizable liquid crystal compound is preferably a smectic phase, and from the perspective of high performance, it is more preferably a high-order smectic phase. Among them, it is more preferred to form a high-order smectic liquid crystal compound of smectic B phase, smectic D phase, smectic E phase, smectic F phase, smectic G phase, smectic H phase, smectic I phase, smectic J phase, smectic K phase or smectic L phase, and it is further preferred to form a high-order smectic liquid crystal compound of smectic B phase, smectic F phase or smectic I phase. When the liquid crystal layer 11 formed by the polymerizable liquid crystal compound is these high-order smectic phases, a region with higher polarization performance can be formed in the liquid crystal layer 11. In addition, for the region with high polarization performance as described above, in the X-ray diffraction measurement, a Bragg peak from a high-order structure such as a hexagonal phase or a crystalline phase can be obtained. The Bragg peak is caused by the periodic structure of molecular orientation, and its periodic interval can be obtained as The polarizing film 1 of this embodiment preferably includes a polymer obtained by polymerizing a polymerizable liquid crystal compound in a smectic phase in the liquid crystal layer 11 because, for example, high polarization characteristics can be imparted to the first region 11 a .

[0095] Whether a polymerizable liquid crystal compound exhibits a nematic liquid crystal phase or a smectic liquid crystal phase can be confirmed, for example, by the following method. A polarizing film-forming composition is applied to a substrate to form a coating film. The coating film is then heat-treated under conditions that prevent polymerization of the polymerizable liquid crystal compound, thereby removing the solvent contained in the coating film. The coating film formed on the substrate is then heated to the isotropic phase temperature and slowly cooled. The resulting liquid crystal phase is then examined by texture observation using a polarizing microscope, X-ray diffraction measurement, or differential scanning calorimetry.

[0096] Specific examples of such polymerizable liquid crystal compounds include compounds represented by the following formula (A) (hereinafter, sometimes referred to as compound (A)).

[0097] U 1 -V 1 -W 1 -X 1 -Y 1 -X 2 -Y 2 -X 3 -W 2 -V 2 -U 2 (A)

[0098] [In formula (A), X1 、X 2 and X 3 Each independently represents a divalent aromatic group or a divalent alicyclic hydrocarbon group, wherein the hydrogen atoms contained in the divalent aromatic group or 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 divalent alicyclic hydrocarbon group may be replaced by an oxygen atom, a sulfur atom, or a nitrogen atom. However, X 1 、X 2 and X 3 At least one of them is 1,4-phenylene which may have a substituent or cyclohexane-1,4-diyl which may have a substituent.

[0099] Y 1 、Y 2 、W 1 and W 2 are independently a single bond or a divalent linking group.

[0100] V 1 and V 2 Each independently represents an alkanediyl group having 1 to 20 carbon atoms which may have a substituent, wherein -CH2- constituting the alkanediyl group may be replaced by -O-, -S- or NH-.

[0101] U 1 and U 2 Each independently represents a polymerizable group or a hydrogen atom, and at least one of them is a polymerizable group.]

[0102] In compound (A), X 1 、X 2 and X 3 At least one of X is a 1,4-phenylene group which may have a substituent, or a cyclohexane-1,4-diyl group which may have a substituent. 1 and X 3 Preferably, the cyclohexane-1,4-diyl group may have a substituent, and the cyclohexane-1,4-diyl group is more preferably a trans-cyclohexane-1,4-diyl group. In the case of a structure containing a trans-cyclohexane-1,4-diyl group, there is a tendency to easily exhibit smectic liquid crystal properties. In addition, as substituents that the 1,4-phenylene group that may have a substituent and the cyclohexane-1,4-diyl group that may have a substituent, examples include alkyl groups having 1 to 4 carbon atoms such as a methyl group, an ethyl group, or a butyl group, a cyano group, and halogen atoms such as a chlorine atom or a fluorine atom. Preferably, the group is unsubstituted.

[0103] Y 1 and Y 2Preferably, each is independently a single bond, -CH2CH2-, -CH2O-, -COO-, -OCO-, -N=N-, -CR a =CR b -、-C≡C- or CR a =N-,R a and R b Y independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. 1 and Y 2 More preferably, it is -CH2CH2-, -COO-, -OCO- or a single bond, X 1 、X 2 and X 3 When neither contains cyclohexane-1,4-diyl, Y 1 and Y 2 Different combination methods. 1 and Y 2 In the case of mutually different bonding modes, smectic liquid crystal properties tend to be easily exhibited.

[0104] W 1 and W 2 Independently of each other, they are preferably a single bond, -O-, -S-, -COO- or OCO-, and independently of each other, they are more preferably a single bond or -O-.

[0105] As V 1 and V 2 The alkane diyl group having 1 to 20 carbon atoms represented by V includes 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, and the like. 1 and V 2 An alkanediyl group having 2 to 12 carbon atoms is preferred, and a linear alkanediyl group having 6 to 12 carbon atoms is more preferred. A linear alkanediyl group having 6 to 12 carbon atoms tends to improve crystallinity and easily exhibit smectic liquid crystallinity.

[0106] Examples of the substituent that the optionally substituted alkanediyl group having 1 to 20 carbon atoms may have include a cyano group and a halogen atom such as a chlorine atom or a fluorine atom. The alkanediyl group is preferably unsubstituted, and more preferably an unsubstituted linear alkanediyl group.

[0107] U 1 and U 2Preferably, all of them are polymerizable groups, more preferably all of them are photopolymerizable groups. Compared with the case of thermally polymerizable groups, polymerizable liquid crystal compounds having photopolymerizable groups can be polymerized under low temperature conditions. Therefore, polymerizable liquid crystal compounds can be formed in a highly ordered state, which is advantageous from this aspect.

[0108] U 1 and U 2 The polymerizable groups represented by may be different from each other, but are preferably the same. Examples of the polymerizable group include vinyl, vinyloxy, 1-chlorovinyl, isopropenyl, 4-vinylphenyl, acryloyloxy, methacryloyloxy, oxirane, and oxetanyl. Among them, acryloyloxy, methacryloyloxy, vinyloxy, oxirane, and oxetanyl are preferred, and methacryloyloxy or acryloyloxy are more preferred.

[0109] Examples of such polymerizable liquid crystal compounds include the following compounds.

[0110]

[0111]

[0112]

[0113] Among the aforementioned compounds, it is preferred to select at least one from the group consisting of compounds represented by formula (1-2), formula (1-3), formula (1-4), formula (1-6), formula (1-7), formula (1-8), formula (1-13), formula (1-14) and formula (1-15).

[0114] The exemplified compound (A) can be used in the liquid crystal layer 11 alone or in combination. In addition, when combining two or more polymerizable liquid crystal compounds, it is preferred that at least one is compound (A), and more preferably two or more are compound (A). By combining two or more polymerizable liquid crystal compounds, liquid crystallinity can sometimes be temporarily maintained even at a temperature below the liquid crystal-crystallization phase transition temperature. As a mixing ratio in the case of combining two polymerizable liquid crystal compounds, it is generally 1:99 to 50:50, preferably 5:95 to 50:50, and more preferably 10:90 to 50:50.

[0115] Compound (A) can be produced by a known method described in, for example, Lub et al., Recl. Trav. Chim. Pays-Bas, 115, 321-328 (1996) or Japanese Patent No. 4719156.

[0116] The content of the polymerizable liquid crystal compound in the liquid crystal layer 11 is typically 50 to 99.5 parts by mass, preferably 60 to 99 parts by mass, more preferably 70 to 98 parts by mass, and even more preferably 80 to 97 parts by mass, relative to 100 parts by mass of the solid content of the liquid crystal layer 11. When the content of the polymerizable liquid crystal compound is within the above range, there is a tendency for improved orientation. The solid content herein refers to the total amount of components remaining after removing the solvent from the polarizing layer-forming composition described later.

[0117] (Dichroic pigment)

[0118] A dichroic dye is a dye that has a different absorbance along the long axis of the molecule than along the short axis. A dichroic dye is a dye that exhibits dichroism by being oriented together with a liquid crystal compound. The dichroic dye itself can be polymerizable or liquid crystal. A dichroic dye preferably has the property of absorbing visible light, and more preferably has a maximum absorption wavelength (λ) in the range of 380 to 680 nm. MAX ). As such dichroic pigments, for example, acridine pigments, oxazine pigments, cyanine pigments, naphthalene pigments, azo pigments or anthraquinone pigments etc. can be enumerated, wherein, azo pigments are preferred. As azo pigments, monoazo pigments, disazo pigments, triazo pigments, tetraazo pigments or stilbene azo pigments etc. can be enumerated, preferably disazo pigments or triazo pigments. Dichroic pigments can be used alone or in combination of two or more. In order to be absorbed in the entire visible light region, it is preferred to combine three or more dichroic pigments, more preferably to combine three or more azo pigments.

[0119] Examples of the azo dye include compounds represented by formula (I) (hereinafter, sometimes also referred to as “compound (I)”).

[0120] T 1 -A 1 (-N=NA 2 ) p -N=NA 3 -T 2 (I)

[0121] [In formula (I), A 1 、A 2 and A 3 Each independently represents a 1,4-phenylene group which may have a substituent, a naphthalene-1,4-diyl group, or a divalent heterocyclic group which may have a substituent, T 1 and T 2 Each of the electron-withdrawing group and the electron-donating group is independently present at a position substantially 180° relative to the azo bond plane. p represents an integer from 0 to 4. When p is 2 or more, each A 2They may be the same or different from each other. Within the range of absorption in the visible light region, the -N=N- bond may be replaced by a -C=C-, -COO-, -NHCO-, or -N=CH- bond.]

[0122] As A 1 、A 2 and A 3 The substituents that the 1,4-phenylene group, naphthalene-1,4-diyl group, and divalent heterocyclic group may optionally have include alkyl groups having 1 to 4 carbon atoms, such as methyl, ethyl, or butyl groups; alkoxy groups having 1 to 4 carbon atoms, such as methoxy, ethoxy, or butoxy groups; fluoroalkyl groups having 1 to 4 carbon atoms, such as trifluoromethyl groups; cyano groups; nitro groups; halogen atoms, such as chlorine atoms and fluorine atoms; and substituted or unsubstituted amino groups, such as amino, diethylamino, and pyrrolidinyl groups (the so-called substituted amino group refers to 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 alkanediyl group having 2 to 8 carbon atoms. The unsubstituted amino group is -NH2.). Examples of the alkyl group having 1 to 6 carbon atoms include methyl, ethyl, and hexyl groups. Examples of the alkane diyl group having 2 to 8 carbon atoms include 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, and octane-1,8-diyl. In order to include compound (I) in a highly ordered liquid crystal structure such as a smectic liquid crystal, A 1 、A 2 and A 3 They are preferably unsubstituted, 1,4-phenylene or a divalent heterocyclic group in which hydrogen is replaced by a methyl group or a methoxy group, and p is preferably 0 or 1. Among them, p is more preferably 1 from the perspective of both ease of molecular synthesis and high performance, and A 1 、A 2 and A 3 At least two of these three structures are 1,4-phenylene groups.

[0123] Examples of the divalent heterocyclic group include groups obtained by removing two hydrogen atoms from quinoline, thiazole, benzothiazole, thienothiazole, imidazole, benzimidazole, oxazole, and benzoxazole. 2 In the case of a divalent heterocyclic group, a structure in which the molecular bond angle is substantially 180° is preferred, and specifically, a benzothiazole, benzimidazole, or benzoxazole structure in which two five-membered rings are fused is more preferred.

[0124] T 1 and T 2 are independently electron-withdrawing groups or electron-donating groups, preferably different structures from each other, and more preferably T 1 is an electron-withdrawing group and T 2is an electron-donating group, or T 1 is an electron-donating group and T 2 is an electron-withdrawing group. Specifically, T 1 and T 2 Independently preferred are an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a cyano group, a nitro group, an amino group having 1 or 2 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 alkanediyl group having 2 to 8 carbon atoms, or a trifluoromethyl group. Among them, in order to be included in a highly ordered liquid crystal structure such as a smectic liquid crystal, a structure with less steric hindrance of the molecule is required. Therefore, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a cyano group, an amino group having 1 or 2 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 alkanediyl group having 2 to 8 carbon atoms is preferred.

[0125] Examples of such azo dyes include the following.

[0126]

[0127] [In formulas (2-1) to (2-6), B 1 ~B 20 Each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 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. In addition, from the viewpoint of obtaining high polarization performance, B 2 、B 6 、B 9 、B 14 、B 18 、B 19 A hydrogen atom or a methyl group is preferred, and a hydrogen atom is more preferred.

[0128] n1 to n4 each independently represent an integer of 0 to 3.

[0129] When n1 is 2 or more, multiple B 2 They can be the same or different.

[0130] When n2 is 2 or more, multiple B 6 They can be the same or different.

[0131] When n3 is 2 or more, multiple B 9 They can be the same or different.

[0132] When n4 is 2 or more, multiple B 14 They can be the same or different.

[0133] As the anthraquinone dye, a compound represented by formula (2-7) is preferred.

[0134]

[0135] [In formula (2-7), R 1 ~R 8 independently represent hydrogen atoms, -R x 、-NH2、-NHR x 、-NR x 2. -SR x or halogen atoms.

[0136] R x represents an alkyl group having 1 to 4 carbon atoms or an aryl group having 6 to 12 carbon atoms.]

[0137] As the oxazine dye, a compound represented by formula (2-8) is preferred.

[0138]

[0139] [In formula (2-8), R 9 ~R 15 independently represent hydrogen atoms, -R x 、-NH2、-NHR x 、-NR x 2. -SR x or halogen atoms.]

[0140] R x represents an alkyl group having 1 to 4 carbon atoms or an aryl group having 6 to 12 carbon atoms.]

[0141] As the acridine dye, a compound represented by formula (2-9) is preferred.

[0142]

[0143] [In formula (2-9), R 16 ~R 23 independently represent hydrogen atoms, -R x 、-NH2、-NHR x 、-NR x 2. -SR x or halogen atoms.

[0144] R x represents an alkyl group having 1 to 4 carbon atoms or an aryl group having 6 to 12 carbon atoms.]

[0145] As R in formula (2-7), formula (2-8) and formula (2-9) xExamples of the alkyl group having 1 to 4 carbon atoms include methyl, ethyl, propyl, butyl, pentyl, and hexyl. Examples of the aryl group having 6 to 12 carbon atoms include phenyl, toluoyl, xylyl, and naphthyl.

[0146] As the cyanine dye, compounds represented by formula (2-10) and compounds represented by formula (2-11) are preferred.

[0147]

[0148] [In formula (2-10), D 1 and D 2 Each independently represents a group represented by any one of formulae (2-10a) to (2-10d).

[0149]

[0150] n5 represents an integer from 1 to 3.]

[0151]

[0152] [In formula (2-11), D 3 and D 4 Each independently represents a group represented by any one of formula (2-11a) to formula (2-11h).

[0153]

[0154] n6 represents an integer from 1 to 3.]

[0155] Regarding the content of the dichroic dye (the ratio of the total amount when multiple types are included), from the perspective of obtaining good light absorption characteristics, in a region with high polarization characteristics such as the first region 11a of the liquid crystal layer 11, where the visibility-corrected polarization degree (Py) is 90% or more, the content is generally preferably 0.1 to 30 parts by mass, more preferably 1 to 20 parts by mass, and even more preferably 3 to 15 parts by mass relative to 100 parts by mass of the polymerizable liquid crystal compound. When the content of the dichroic dye is less than the above range, light absorption becomes insufficient and sufficient polarization performance cannot be obtained. When the content of the dichroic dye is more than the above range, the orientation of the liquid crystal molecules may be sometimes hindered. In a region with low polarization characteristics such as the second region 11b of the liquid crystal layer 11, where the visibility-corrected polarization degree (Py) is 10% or less, the content is generally preferably 0 to 20 parts by mass, more preferably 0 to 10 parts by mass, and even more preferably 0 to 5 parts by mass relative to 100 parts by mass of the polymerizable liquid crystal compound.

[0156] (Base material layer)

[0157] The polarizing film 1 may include a substrate layer 13. The substrate layer 13 may be used to support the alignment layer 12 and the polarizing layer 21 described later when manufacturing the polarizing film 1, and may also be used to support the liquid crystal layer 11 of the polarizing film 1, as described later.

[0158] The substrate layer 13 can be a glass substrate or a resin substrate, preferably a resin substrate. Furthermore, to enable continuous production of the polarizing film 1, the substrate layer 13 is more preferably a layer obtained by unwinding a long, rolled-up resin substrate. The resin substrate is preferably a substrate having light transmittance that allows visible light to pass through. Light transmittance herein refers to a visibility-corrected single-piece transmittance of 80% or greater for light in the wavelength range of 380 to 780 nm.

[0159] As for the thickness of the substrate layer 13, the thinner the better, considering the quality of the degree to which it can be handled practically. However, if it is too thin, the strength is reduced and there is a tendency for poor processability. The thickness of the substrate layer 13 is generally 5 μm to 300 μm, preferably 20 μm to 200 μm. In addition, the substrate layer 13 can be provided in a removable manner. For example, it can be a substrate layer that can be peeled off from the polarizing film 1 after the liquid crystal layer 11 of the polarizing film 1 is attached to a component that becomes a display device, a phase difference layer described later, etc. In this way, a further thinning effect of the polarizing film 1 can be obtained.

[0160] Examples of the resin constituting the resin substrate include polyolefins such as polyethylene and polypropylene; cyclic olefin resins such as norbornene polymers; polyvinyl alcohol; polyethylene terephthalate; polymethacrylate; polyacrylate; cellulose esters such as triacetyl cellulose, diacetyl cellulose, and cellulose acetate propionate; polyethylene naphthalate; polycarbonate; polysulfone; polyethersulfone; polyetherketone; polyphenylene sulfide and polyphenylene ether; and the like.

[0161] Examples of commercially available cellulose ester resin substrates include "Fujitack Film" (manufactured by Fuji Photo Film Co., Ltd.); "KC8UX2M," "KC8UY," and "KC4UY" (all manufactured by Konica Minolta Opto Co., Ltd.).

[0162] Examples of commercially available cyclic olefin resins include "Topas" (registered trademark) (manufactured by Ticona GmbH (Germany)), "ARTON" (registered trademark) (manufactured by JSR Corporation), "ZEONOR" (registered trademark), "ZEONEX" (registered trademark) (all manufactured by ZEON Corporation of Japan), and "APEL" (registered trademark) (manufactured by Mitsui Chemicals, Inc.). Such cyclic olefin resins can be formed into films using known methods such as solvent casting and melt extrusion to form a resin substrate. A resin substrate made of a commercially available cyclic olefin resin can also be used. Examples of commercially available cyclic olefin resin substrates include "ESCENA" (registered trademark), "SCA40" (registered trademark) (all manufactured by Sekisui Chemical Co., Ltd.), "ZEONOR FILM" (registered trademark) (manufactured by OPTES Co., Ltd.), and "ARTON Film" (registered trademark) (manufactured by JSR Corporation).

[0163] The base material layer 13 may have a single-layer structure or a multi-layer structure of two or more layers. When the base material layer 13 has a multi-layer structure, each layer may be formed of the same material or may be formed of different materials.

[0164] In addition, the substrate layer 13 may have a 1 / 4 wavelength plate function. By making the substrate layer 13 have a 1 / 4 wavelength plate function, it is possible to obtain a polarizing film having the function of a circular polarizing plate by utilizing the combination of the substrate layer 13 and the liquid crystal layer 11. Thus, even if a phase difference layer having a 1 / 4 wavelength plate function other than the substrate layer 13 is not attached to the polarizing film 1, a circular polarizing plate can be obtained. In addition, when the substrate layer 13 is a multilayer structure, a product in which a layer having a 1 / 2 wavelength plate function and a layer having a 1 / 4 wavelength plate function are stacked together, and the liquid crystal layer 11 is stacked on the side of the layer having a 1 / 2 wavelength plate function, thereby obtaining a circular polarizing plate. Alternatively, when the substrate layer 13 is a multilayer structure, a product in which a layer having a 1 / 4 wavelength plate function with reverse wavelength dispersion and a layer having a positive C plate function are stacked together can also be used to obtain a circular polarizing plate.

[0165] (Orientation Layer)

[0166] The polarizing film 1 may include an alignment layer 12 on a substrate layer 13, and the alignment layer 12 may be disposed between the substrate layer 13 and the liquid crystal layer 11. The alignment layer 12 may have an alignment regulating force for aligning the liquid crystal compound in the liquid crystal layer 11 stacked thereon in a desired direction.

[0167] The orientation layer 12 facilitates the liquid crystal orientation of the liquid crystal compound. The state of the liquid crystal orientation, such as horizontal orientation, vertical orientation, mixed orientation, and tilted orientation, varies depending on the properties of the orientation layer 12 and the liquid crystal compound, and their combination can be selected arbitrarily. For example, if the orientation layer 12 is a material that allows horizontal orientation as an orientation limiting force, the liquid crystal compound can form a horizontal orientation or a mixed orientation. If the orientation layer 12 is a material that allows vertical orientation, the liquid crystal compound can form a vertical orientation or a tilted orientation. Expressions such as horizontal and vertical indicate the direction of the long axis of the oriented liquid crystal compound with the plane of the polarizing film 1 as a reference. For example, vertical orientation refers to the long axis of the polymerizable liquid crystal oriented in a direction perpendicular to the plane of the polarizing film 1. The so-called vertical here means 90°±20° relative to the plane of the polarizing film 1. The polarizing film 1 preferably has polarization characteristics in the plane of the polarizing film 1, and therefore, the orientation layer 12 is preferably formed using a material that allows horizontal orientation.

[0168] The orientation regulating force of the orientation layer 12 can be arbitrarily adjusted by the surface state and rubbing conditions when the orientation layer 12 is formed of an aligning polymer, and by polarized light irradiation conditions when the orientation layer 12 is formed of a photoaligning polymer. Furthermore, the liquid crystal orientation can be controlled by selecting physical properties such as the surface tension and liquid crystallinity of the polymerizable liquid crystal compound.

[0169] The thickness of the alignment layer 12 is generally 10 nm to 5000 nm, preferably 10 nm to 1000 nm, and more preferably 30 nm to 300 nm. Furthermore, the alignment layer 12 formed between the substrate layer 13 and the liquid crystal layer 11 is preferably insoluble in the solvent used when forming the liquid crystal layer 11 on the alignment layer 12 and has heat resistance during the heat treatment used to remove the solvent and align the liquid crystal.

[0170] Examples of the orientation layer 12 include an orientation film formed from an orientation polymer, a photo-alignment film, or a groove orientation film. When the substrate layer 13 is a product obtained by unwinding a long roll of a resin substrate, the orientation layer 12 is preferably a photo-alignment film because its orientation direction can be easily controlled.

[0171] As the oriented polymer, polyamide, gelatin, polyimide with amide bond in molecule, polyamic acid, polyvinyl alcohol, alkyl-modified polyvinyl alcohol, polyacrylamide, polyoxazole, polyethyleneimine, polystyrene, polyvinyl pyrrolidone, polyacrylic acid or polyacrylate etc. as its hydrolyzate can be enumerated.Wherein, preferred polyvinyl alcohol.These oriented polymers can be used alone, and also can be used in combination of two or more.

[0172] An oriented film formed by an oriented polymer can generally be obtained by applying a composition obtained by dissolving an oriented polymer in a solvent (hereinafter sometimes referred to as an "oriented polymer composition") to the substrate layer 13 and removing the solvent; or, applying the oriented polymer composition to the substrate layer 13, removing the solvent, and rubbing (rubbing method).

[0173] Examples of solvents that can be used in the oriented polymer composition include water; alcohol solvents such as methanol, ethanol, ethylene glycol, isopropyl alcohol, propylene glycol, methyl cellosolve, butyl cellosolve, or propylene glycol monomethyl ether; ester solvents such as ethyl acetate, butyl acetate, ethylene glycol methyl ether acetate, γ-butyrolactone, propylene glycol methyl ether acetate, or ethyl lactate; ketone solvents such as acetone, methyl ethyl ketone, cyclopentanone, cyclohexanone, methyl amyl ketone, or methyl isobutyl ketone; aliphatic hydrocarbon solvents such as pentane, hexane, or heptane; aromatic hydrocarbon solvents such as toluene or xylene; nitrile solvents such as acetonitrile; ether solvents such as tetrahydrofuran or dimethoxyethane; chlorine-substituted hydrocarbon solvents such as chloroform or chlorobenzene; and the like. These solvents may be used alone or in combination of two or more.

[0174] The content of the oriented polymer in the oriented polymer composition may be such that the oriented polymer can be completely dissolved in the solvent, and is preferably 0.1 to 20% by mass, more preferably 0.1 to 10% by mass, based on the solid content of the solution.

[0175] As the oriented polymer composition, a commercially available oriented film material can be used as it is. Examples of commercially available oriented film materials include SUNEVER (registered trademark) (manufactured by Nissan Chemical Industries, Ltd.) and OPTMER (registered trademark) (manufactured by JSR Corporation).

[0176] Examples of methods for coating the oriented polymer composition on the substrate layer 13 include known methods such as spin coating, extrusion, gravure coating, die coating, rod coating, or applicator coating, and printing methods such as flexographic methods. When the polarizing film 1 is produced by a roll-to-roll continuous production method, the coating method generally employs gravure coating, die coating, or printing methods such as flexographic methods.

[0177] By removing the solvent from the oriented polymer composition, a dry film of the oriented polymer can be formed. Examples of methods for removing the solvent include natural drying, ventilation drying, heat drying, and reduced-pressure drying. Subsequently, the dry film is brought into contact with a rotating rubbing roller wrapped with a rubbing cloth to form the oriented layer 12.

[0178] A photo-alignment film can generally be obtained by irradiating a coating layer for an alignment layer formed by applying a composition containing a polymer or monomer having a photoreactive group and a solvent (hereinafter sometimes referred to as a "photo-alignment film-forming composition") to the substrate layer 13 with polarized light (preferably polarized UV light). A photo-alignment film is more preferred because the direction of the alignment regulating force can be arbitrarily controlled by selecting the polarization direction of the irradiated polarized light.

[0179] The so-called photoreactive group refers to a group that generates liquid crystal orientation ability by irradiating light. Specifically, it refers to a group that can induce the orientation of molecules caused by irradiating light or an isomerization reaction, dimerization reaction, photocrosslinking reaction, or photodecomposition reaction, which is the origin of the liquid crystal orientation ability. Among the above-mentioned photoreactive groups, groups that can undergo dimerization reaction or photocrosslinking reaction are preferred from the perspective of excellent orientation. As a photoreactive group that can undergo the above reaction, a photoreactive group having an unsaturated bond, especially a double bond, is preferably 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).

[0180] As photoreactive groups having a C=C bond, for example, vinyl, polyene, stilbene, stilbazole, stilbazolium, chalcone or cinnamoyl groups can be mentioned. From the perspective of ease of controlling reactivity and the presentation of orientation restriction forces during photo-orientation, chalcone or cinnamoyl groups are preferred. As photoreactive groups having a C=N bond, groups having structures such as aromatic Schiff bases or aromatic hydrazones can be mentioned. As photoreactive groups having an N=N bond, groups having azobenzene, azonaphthyl, aromatic heterocyclic azo, disazo or formazan groups, and groups with oxidized azobenzene as the basic structure can be mentioned. As photoreactive groups having a C=O bond, groups having a benzophenone group, coumarin group, anthraquinone group or maleimide group can be mentioned. These groups may have a substituent 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, or a haloalkyl group.

[0181] The solvent of the photo-alignment film-forming composition is preferably a solvent that dissolves the polymer and monomer having a photoreactive group. Examples of the solvent include the solvents listed above as the solvent for the alignment polymer composition.

[0182] The content of the polymer or monomer having a photoreactive group in the composition for forming a photo-alignment film can be appropriately adjusted depending on the type of polymer or monomer having a photoreactive group and the thickness of the photo-alignment film to be produced, and is preferably 0.2% by mass or greater, particularly preferably in the range of 0.3% to 10% by mass. Furthermore, polymer materials such as polyvinyl alcohol and polyimide, and photosensitizers may be included within a range that does not significantly impair the properties of the photo-alignment film.

[0183] The method for applying the photo-alignment film-forming composition to the substrate layer 13 may be the same method as the method for applying the oriented polymer composition to the substrate layer 13. The method for removing the solvent from the applied photo-alignment film-forming composition may be the same method as the method for removing the solvent from the oriented polymer composition.

[0184] Polarized light irradiation can be performed directly on the dried film after removing the solvent from the composition for forming a photo-alignment film applied on the substrate layer 13, or it can be performed from the side of the substrate layer 13 in a manner that the polarized light passing through the substrate layer 13 is irradiated onto the dried film. In addition, it is particularly preferred that the polarized light used for polarized light irradiation is substantially parallel light. The wavelength of the polarized light irradiated is preferably a wavelength in the wavelength region in which the photoreactive group of the polymer or monomer having a photoreactive group can absorb light energy. Specifically, UV (ultraviolet light) with a wavelength range of 250 to 400 nm is particularly preferred. As light sources for polarized light irradiation, xenon lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, metal halide lamps, ultraviolet lasers such as KrF and ArF can be cited, and high-pressure mercury lamps, ultra-high-pressure mercury lamps or metal halide lamps are more preferred. These lamps are preferred because the luminous intensity of ultraviolet light with a wavelength of 313 nm is large. Polarized light can be irradiated by passing light from a light source through an appropriate polarizer. As the polarizer, a polarizing filter, a polarizing prism such as a Glan-Thompson or Glan-Taylor polarizer, or a wire grid polarizer can be used.

[0185] In addition, if masking is performed during rubbing or polarized light irradiation, a plurality of regions (patterns) in which the directions of liquid crystal alignment are different can be formed.

[0186] A groove alignment film is a film with a concavo-convex pattern or multiple grooves on its surface. When liquid crystal molecules are placed on a film with multiple linear grooves arranged at equal intervals, the liquid crystal molecules align along the grooves.

[0187] Examples of methods for obtaining a grooved alignment film include: a method in which a photosensitive polyimide film surface is exposed through an exposure mask having patterned slits, followed by development and rinsing to form a concave-convex pattern; a method in which a layer of a pre-cured UV-curable resin is formed on a plate-like original plate having grooves on its surface, the resin layer is transferred to a substrate, and then cured; a method in which a roll-like original plate having multiple grooves is pressed against a pre-cured UV-curable resin film formed on a substrate to form the concave-convex pattern, and the concave-convex pattern is then cured. Specifically, examples include the methods described in Japanese Patent Application Publication Nos. 6-34976 and 2011-242743.

[0188] In order to obtain an orientation with less disordered orientation, the width of the convex portion of the groove alignment film is preferably 0.05 μm to 5 μm, the width of the concave portion is preferably 0.1 μm to 5 μm, and the depth of the height difference between the concave and convex is preferably 2 μm or less, preferably 0.01 μm to 1 μm or less.

[0189] (Other layers)

[0190] The polarizing film 1 may include layers other than the substrate layer 13 and the alignment layer 12. For example, a surface protective layer may be provided on the surface of the liquid crystal layer 11 opposite to the substrate layer 13, for the purpose of protecting the surface of the liquid crystal layer 11. Furthermore, when the substrate layer 13 is peeled off for use, a surface protective layer may be provided on the surface of the liquid crystal layer 11 from which the substrate layer 13 has been peeled off. The surface protective layer may have a single-layer structure or a multi-layer structure. In the case of a multi-layer structure, each layer may be formed of the same material or different materials.

[0191] Circularly polarizing plate

[0192] Figure 2 (a) to (c) are schematic cross-sectional views showing an example of the circularly polarizing plate of the present invention. Figure 1 The polarizing film 1 shown in (b) is laminated with the phase difference layer 15 having the function of a quarter wavelength plate, and can be formed into Figure 2 (a) and (b) circular polarizers 5a, 5b. The phase difference layer 15 can be laminated on the liquid crystal layer 11 side of the polarizing film 1 ( Figure 2 (a)), it can also be laminated on the base material layer 13 side ( Figure 2 (b)). Alternatively, you can Figure 2 The circularly polarizing plate 5a shown in (a) is obtained by peeling off the base material layer 13 as the circularly polarizing plate 5c ( Figure 2 (c)) is used. In this case, the orientation layer 12 and the base material layer 13 can also be peeled off together.

[0193] In addition, the circularly polarizing plate may be a product obtained by laminating a polarizing film 1 with a phase difference layer of a multilayer structure. In this case, a phase difference layer obtained by laminating a layer having a 1 / 2 wavelength plate function and a layer having a 1 / 4 wavelength plate function can be used as the phase difference layer of the multilayer structure, and a circularly polarizing plate can be prepared by laminating the layer side having the 1 / 2 wavelength plate function of the multilayer structure phase difference layer with the polarizing film 1. Alternatively, a circularly polarizing plate can be obtained by laminating a phase difference layer obtained by laminating a layer having a 1 / 4 wavelength plate function with a layer having a reverse wavelength dispersion and a layer having a positive C plate function as the phase difference layer of the multilayer structure.

[0194] Alternatively, a layer that functions as a retardation layer can be used as the substrate layer 13 of the polarizing film 1, and then laminated with the retardation layer to produce a circularly polarizing plate. In this case, the functions of the substrate layer 13 and the retardation layer as the retardation layer can be selected based on the lamination positions of the substrate layer 13 and the retardation layer in the circularly polarizing plate.

[0195] The polarizing film and the retardation layer can be laminated via an adhesive layer using a known adhesive or pressure-sensitive adhesive.

[0196] <Method for Manufacturing Polarizing Film (First Manufacturing Method)>

[0197] Figure 3 (a) to (d) represent Figure 1 (b) is a schematic cross-sectional view of the layer structure obtained in each step of the production process of the polarizing film 1. The first production method of the polarizing film 1 includes the following steps:

[0198] Preparation step: preparing a laminated film 62 ( Figure 3 (b)); and

[0199] The liquid material contact step reduces the dichroic dye content in a portion of the polarizing layer 21 by bringing a portion of the polarizing layer 21 of the laminated film 62 into contact with a liquid material capable of reducing the dichroic dye content in the polarizing layer 21 .

[0200] By making the liquid material contacting step include the following steps, it is possible to produce Figure 1 (b) Polarizing film 1 shown:

[0201] In the protective layer lamination step, a protective layer 35 having a covering region 35a for covering the polarizing layer 21 and an exposed region 35b for exposing the polarizing layer 21 is laminated on the polarizing layer 21 of the laminate film 62, thereby obtaining a laminate film 63 ( Figure 3 (c));

[0202] In the decolorization step, the laminated film 63 with the protective layer is brought into contact with a liquid capable of reducing the content of the dichroic pigment in the polarizing layer 21, thereby obtaining a decolorized laminated film 64 ( Figure 3 (d)); and

[0203] In the peeling step, the protective layer 35 is peeled off from the decolorizing laminate film 64 .

[0204] (Preparation process)

[0205] The laminated film 62 prepared in the preparation step is not particularly limited as long as it is a laminated film having a polarizing layer 21 on at least one side of the substrate layer 13, such as Figure 3 As shown in FIG. 1( b ), a laminated film is preferably formed by sequentially laminating an alignment layer 12 and a polarizing layer 21 on a substrate layer 13. Such a laminated film 62 can be manufactured by the following steps: an alignment layer forming step in which an alignment layer forming composition is applied to one surface of the substrate layer 13 to form the alignment layer 12, thereby obtaining a substrate layer 61 with an alignment layer ( Figure 3 and a polarizing layer forming step, on the surface of the substrate layer 61 with an alignment layer on which the alignment layer 12 is formed, a polarizing layer forming composition is applied to form the polarizing layer 21 .

[0206] In the alignment layer forming process, the substrate layer 13 may be surface treated before applying the alignment layer forming composition. Examples of surface treatment methods include corona treatment, plasma treatment, laser treatment, ozone treatment, saponification treatment, flame treatment, coupling agent coating treatment, primer treatment, and the like. As alignment layer forming compositions, the above-mentioned alignment polymer compositions, photo-alignment film forming compositions, and compositions comprising resin materials for forming groove alignment films may be used. The method for forming an alignment layer using each composition is also as described above. For example, when the alignment layer forming composition comprises a photo-alignment polymer, for the alignment layer forming process, the alignment layer coating layer formed by applying the alignment layer forming composition is subjected to polarized light irradiation, thereby forming an alignment layer having an alignment limiting force in a predetermined direction.

[0207] The polarizing layer-forming composition preferably comprises a liquid crystal compound and a dichroic dye, and preferably comprises a solvent and a polymerization initiator. It may also comprise a sensitizer, a polymerization inhibitor, a leveling agent, a reactive additive, etc. The liquid crystal compound and the dichroic dye described above can be used as the liquid crystal compound and the dichroic dye, and the solvent, the polymerization initiator, the sensitizer, the polymerization inhibitor, the leveling agent, and the reactive additive can be those described below.

[0208] As a method for coating the polarizing layer forming composition, extrusion coating, direct gravure coating, reverse gravure coating, CAP coating, slit coating, micro gravure, die coating, inkjet coating, etc. can be mentioned. In addition, a method for coating using a coating machine such as a dip coater, a rod coater, a spin coater, etc. can also be mentioned. Among them, when continuously coated in a roll-to-roll (Roll to Roll) form, it is preferably a coating method using a micro gravure, inkjet, slit coating, die coating, and when coated on a monolithic substrate such as glass, it is preferably a spin coating method with high uniformity. When coated in a roll-to-roll (Roll to Roll) form, it is also possible to apply an alignment film forming composition on the substrate layer 13 to form an alignment layer 12, and then continuously apply a polarizing layer forming composition on the obtained alignment layer 12.

[0209] When the polarizing layer 21 is formed by coating the polarizing layer-forming composition, the solvent is removed from the coated polarizing layer-forming composition to form a polarizing layer coating layer. As a method for removing the solvent, the same method as the method for removing the solvent from the oriented polymer composition can be used, and examples thereof include natural drying, ventilation drying, heat drying, reduced pressure drying, and a combination thereof. Among them, natural drying or heat drying is preferred. The drying temperature is preferably in the range of 0 to 200°C, more preferably in the range of 20 to 150°C, and further preferably in the range of 50 to 130°C. The drying time is preferably 10 seconds to 10 minutes, more preferably 30 seconds to 5 minutes.

[0210] In the case where the liquid crystal compound contained in the polarizing layer forming composition is a polymerizable liquid crystal compound, it is preferred that the polarizing layer coating layer formed in the polarizing layer forming process is irradiated with active energy rays, so that the polymerizable liquid crystal compound is photopolymerized to form a polarizing layer 21 as a polymer layer of the polymerizable liquid crystal compound. As the active energy ray irradiated, it can be appropriately selected according to the type of polymerizable liquid crystal compound contained in the polarizing layer coating layer (especially the type of photopolymerizable functional group possessed by the polymerizable liquid crystal compound), the type of photopolymerization initiator when a photopolymerization initiator is included, and their amount. Specifically, one or more lights selected from the group consisting of visible light, ultraviolet light, infrared light, X-rays, α rays, β rays, and γ rays can be cited. Among them, from the perspective of easily controlling the progress of the polymerization reaction and being able to use a device that has been widely used as a photopolymerization device in the art, ultraviolet light is preferred, and the type of polymerizable liquid crystal compound is preferably selected in a manner that can be photopolymerized using ultraviolet light.

[0211] Examples of light sources for active energy rays include low-pressure mercury lamps, medium-pressure mercury lamps, high-pressure mercury lamps, ultra-high-pressure mercury lamps, xenon lamps, halogen lamps, carbon arc lamps, tungsten lamps, gallium lamps, excimer lasers, LED light sources emitting light in a wavelength range of 380 to 440 nm, chemical lamps, black light lamps, microwave-excited mercury lamps, and metal halide lamps.

[0212] The irradiation intensity of active energy rays is usually 10mW / cm 2 ~3000mW / cm 2 The irradiation intensity of the active energy ray is preferably an intensity in a wavelength region effective for activating a cationic polymerization initiator or a free radical polymerization initiator. The irradiation time of the active energy ray is usually 0.1 second to 10 minutes, preferably 0.1 second to 5 minutes, more preferably 0.1 second to 3 minutes, and further preferably 0.1 second to 1 minute. When irradiating once or multiple times with such an irradiation intensity of the active energy ray, the cumulative light amount can be 10 mJ / cm 2 ~3000mJ / cm 2 , preferably 50 mJ / cm 2 ~2,000mJ / cm 2 , more preferably 100 mJ / cm 2 ~1000mJ / cm 2 If the accumulated light intensity is below the above range, the curing of the polymerizable liquid crystal compound may be insufficient, and good transferability may not be achieved. On the other hand, if the accumulated light intensity is above the above range, the polarizing layer may be colored.

[0213] (Solvent)

[0214] The polarizing layer-forming composition may contain a solvent. Generally, due to the high viscosity of polymerizable liquid crystal compounds, when using a polymerizable liquid crystal compound as the liquid crystal compound, the polarizing layer-forming composition containing a solvent facilitates coating, thereby facilitating the formation of a polarizing layer. As a solvent, preferably, a solvent that can completely dissolve the polymerizable liquid crystal compound and the dichroic dye is preferably a solvent that is inert with respect to the polymerization reaction of the polymerizable liquid crystal compound.

[0215] Examples of the solvent include alcohol solvents such as methanol, ethanol, ethylene glycol, isopropanol, propylene glycol, ethylene glycol methyl ether, ethylene glycol butyl ether, or propylene glycol monomethyl ether; ester solvents such as ethyl acetate, butyl acetate, ethylene glycol methyl ether acetate, γ-butyrolactone, propylene glycol methyl ether acetate, or ethyl lactate; ketone solvents such as acetone, methyl ethyl ketone, cyclopentanone, cyclohexanone, 2-heptanone, or methyl isobutyl ketone; aliphatic hydrocarbon solvents such as pentane, hexane, or heptane; aromatic hydrocarbon solvents such as toluene or xylene; nitrile solvents such as acetonitrile; ether solvents such as tetrahydrofuran or dimethoxyethane; chlorine-containing solvents such as chloroform or chlorobenzene; and amide solvents such as dimethylacetamide, dimethylformamide, N-methyl-2-pyrrolidone, and 1,3-dimethyl-2-imidazolidinone. These solvents may be used alone or in combination of two or more.

[0216] The content of the solvent contained in the polarizing layer-forming composition is preferably 50 to 98% by mass relative to the total amount of the polarizing layer-forming composition. In other words, the solid content in the polarizing layer-forming composition is preferably 2 to 50% by mass. When the solid content is 50% by mass or less, the viscosity of the polarizing layer-forming composition decreases, thereby tending to make the thickness of the polarizing layer 21 substantially uniform and less prone to unevenness in the polarizing layer 21. The solid content can be determined in consideration of the thickness of the polarizing layer 21 to be manufactured.

[0217] (Polymerization initiator)

[0218] The polarizing layer-forming composition may contain a polymerization initiator. A polymerization initiator can be used when a polymerizable liquid crystal compound is used as the liquid crystal compound. It is a compound that can initiate a polymerization reaction of the polymerizable liquid crystal compound. As the polymerization initiator, a photopolymerization initiator that generates active free radicals in response to light is preferred because it is independent of the phase state of the thermotropic liquid crystal.

[0219] Examples of the polymerization initiator include benzoin compounds, benzophenone compounds, alkylphenone compounds, acylphosphine oxide compounds, triazine compounds, iodonium salts, and sulfonium salts.

[0220] Examples of the benzoin compound include benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isopropyl ether and benzoin isobutyl ether.

[0221] Examples of the benzophenone compound include benzophenone, methyl o-benzoylbenzoate, 4-phenylbenzophenone, 4-benzoyl-4′-methyldiphenyl sulfide, 3,3′,4,4′-tetrakis(tert-butylperoxycarbonyl)benzophenone, and 2,4,6-trimethylbenzophenone.

[0222] Examples of the alkylphenone compound include diethoxyacetophenone, 2-methyl-2-morpholino-1-(4-methylthiophenyl)propane-1-one, 2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butane-1-one, 2-hydroxy-2-methyl-1-phenylpropane-1-one, 1,2-diphenyl-2,2-dimethoxyethane-1-one, 2-hydroxy-2-methyl-1-[4-(2-hydroxyethoxy)phenyl]propane-1-one, 1-hydroxycyclohexylphenyl ketone, and oligomers of 2-hydroxy-2-methyl-1-[4-(1-methylvinyl)phenyl]propane-1-one.

[0223] Examples of the acylphosphine oxide compound include 2,4,6-trimethylbenzoyldiphenylphosphine oxide and bis(2,4,6-trimethylbenzoyl)phenylphosphine oxide.

[0224] Examples of the triazine compound include 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-methoxyphenyl)-1,3,5-triazine, 2,4-bis(trichloromethyl)-6-(4-methoxyphenyl)-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 or 2,4-bis(trichloromethyl)-6-[2-(3,4-dimethoxyphenyl)vinyl]-1,3,5-triazine, etc.

[0225] A commercially available polymerization initiator may be used as the polymerization initiator. Examples of commercially available polymerization initiators include Irgacure (registered trademark) 907, 184, 651, 819, 250, 369, 379, 127, 754, OXE01, OXE02, and OXE03 (manufactured by Ciba Specialty Chemicals, Inc.); SEIKUOL (registered trademark) BZ, Z, or BEE (manufactured by Seiko Chemical Co., Ltd.); Kayacure (registered trademark) BP100 or UVI-6992 (manufactured by Dow Chemical Company); ADEKA OPTOMER SP-152, N-1717, N-1919, SP-170, ADEKA ARKLS NCI-831, and ADEKA ARKLS NCI-930 (manufactured by ADEKA Co., Ltd.); TAZ-A or TAZ-PP (manufactured by Nippon Siber Hegner Co., Ltd.); TAZ-104 (manufactured by Sanwa Chemical Co., Ltd.); etc. The polymerization initiator in the polarizing layer-forming composition may be used alone or as a mixture of two or more polymerization initiators depending on the light source.

[0226] The content of the polymerization initiator in the polarizing layer-forming composition can be appropriately adjusted depending on the type and amount of the polymerizable liquid crystal compound, and is generally 0.1 to 30 parts by mass, preferably 0.5 to 10 parts by mass, and more preferably 0.5 to 8 parts by mass, relative to 100 parts by mass of the polymerizable liquid crystal compound. When the content of the polymerization initiator is within this range, polymerization can proceed without disturbing the alignment of the polymerizable liquid crystal compound.

[0227] (Sensitizer)

[0228] The polarizing layer-forming composition may contain a sensitizer. The sensitizer can be suitably used when a polymerizable liquid crystal compound is used as the liquid crystal compound. When a polymerizable liquid crystal compound having a photopolymerizable group is used, the sensitizer is preferably a photosensitizer. Examples of the sensitizer include xanthone compounds such as xanthone and thioxanthone (e.g., 2,4-diethylthioxanthone, 2-isopropylthioxanthone, etc.); anthracene compounds such as anthracene and anthracene containing an alkoxy group (e.g., dibutoxyanthracene, etc.); phenothiazine, rubrene, etc.

[0229] When the polarizing layer-forming composition contains a sensitizer, the polymerization reaction of the polymerizable liquid crystal compound contained in the polarizing layer-forming composition can be further promoted. The amount of the sensitizer used is preferably 0.1 to 10 parts by mass, more preferably 0.5 to 5 parts by mass, and even more preferably 0.5 to 3 parts by mass, relative to 100 parts by mass of the polymerizable liquid crystal compound.

[0230] (Polymerization Inhibitor)

[0231] The polarizing layer-forming composition may contain a polymerization inhibitor to stabilize the polymerization reaction. A polymerization inhibitor is preferably used when a polymerizable liquid crystal compound is used as the liquid crystal compound, and can control the degree of polymerization of the polymerizable liquid crystal compound.

[0232] Examples of the polymerization inhibitor include hydroquinone, alkoxy-containing hydroquinone, alkoxy-containing catechol (e.g., butyl catechol), pyrogallol, and radical scavengers such as 2,2,6,6-tetramethylpiperidin-1-oxyl; thiophenols; β-naphthylamines; and β-naphthols.

[0233] When the polarizing layer-forming composition contains a polymerization inhibitor, the amount of the polymerization inhibitor is preferably 0.1 to 10 parts by mass, more preferably 0.5 to 5 parts by mass, and even more preferably 0.5 to 3 parts by mass, relative to 100 parts by mass of the polymerizable liquid crystal compound. When the polymerization inhibitor content is within this range, polymerization can proceed without disturbing the alignment of the polymerizable liquid crystal compound.

[0234] (Leveling agent)

[0235] The polarizing layer-forming composition may contain a leveling agent. A leveling agent is an additive that adjusts the fluidity of the composition and makes the film obtained by coating the composition flatter. Examples of such leveling agents include organically modified silicone oil-based, polyacrylate-based, and perfluoroalkyl-based leveling agents.Specific examples include DC3PA, SH7PA, DC11PA, SH28PA, SH29PA, SH30PA, ST80PA, ST86PA, SH8400, SH8700, and FZ2123 (all manufactured by Dow Corning Toray Co., Ltd.), KP321, KP323, KP324, KP326, KP340, KP341, X22-161A, and KF6001 (all manufactured by Shin-Etsu Chemical Co., Ltd.), TSF400, TSF401, TSF410, TSF4300, TSF4440, TSF4445, TSF-4446, TSF4452, and TSF4460 (all manufactured by Momentive Performance Materials Japan LLC), fluorinert (registered trademark) FC-72, and fluorinert FC-40, fluorinert FC-43, fluorinert FC-3283 (all manufactured by Sumitomo 3M Co., Ltd.), MEGAFACE (registered trademark) R-08, MEGAFACE R-30, MEGAFACE R-90, MEGAFACE F-410, MEGAFACE F-411, MEGAFACE F-443, MEGAFACE F-445, MEGAFACE F-470, MEGAFACE F-477, MEGAFACE F-479, MEGAFACE F-482, MEGAFACE F-483 (all manufactured by DIC Corporation), EFTOP (trade name) EF301, EFTOP EF303, EFTOP EF351, EFTOP EF352 (all manufactured by Mitsubishi Materials Electronic Chemicals Co., Ltd.), Surflon (registered trademark) S-381, Surflon S-382, Surflon S-383, Surflon S-393, Surflon SC-101, Surflon SC-105, KH-40, SA-100 (all manufactured by AGC Seimi Chemical Co., Ltd.), trade name E1830, trade name E5844 (manufactured by Daikin Fine Chemical Kenkyusho, KK), BM-1000, BM-1100, BYK-352, BYK-353, or BYK-361N (all trade names: manufactured by BM Chemie Co., Ltd.), etc. Among them, polyacrylate-based leveling agents or perfluoroalkyl-based leveling agents are preferred.

[0236] When the polarizing layer-forming composition contains a leveling agent, the amount thereof is preferably 0.01 to 5 parts by mass, more preferably 0.1 to 5 parts by mass, and still more preferably 0.1 to 3 parts by mass relative to 100 parts by mass of the liquid crystal compound. When the content of the leveling agent is within the above range, there is a tendency to easily align the liquid crystal compound horizontally, and the resulting polarizing layer becomes smoother. When the content of the leveling agent relative to the liquid crystal compound exceeds the above range, there is a tendency to easily produce unevenness in the resulting polarizing layer. It should be noted that the polarizing layer-forming composition may contain two or more leveling agents.

[0237] (Reactive Additives)

[0238] The polarizing layer forming composition may contain a reactive additive. As the reactive additive, an additive having a carbon-carbon unsaturated bond and an active hydrogen reactive group in its molecule is preferred. It should be noted that the so-called "active hydrogen reactive group" here refers to a group that is reactive with respect to a group having active hydrogen, such as a carboxyl group (-COOH), a hydroxyl group (-OH), an amino group (-NH2), and glycidyl group, oxazoline group, carbodiimide group, aziridine group, imide group, isocyanate group, isothiocyanate group, maleic anhydride group, etc. are representative examples thereof. The number of carbon-carbon unsaturated bonds or active hydrogen reactive groups possessed by the reactive additive is generally 1 to 20, respectively, and preferably 1 to 10, respectively.

[0239] It is preferred that at least two active hydrogen-reactive groups are present in the reactive additive. In this case, the plurality of active hydrogen-reactive groups may be the same or different.

[0240] The carbon-carbon unsaturated bond possessed by the reactive additive may be a carbon-carbon double bond, a carbon-carbon triple bond, or a combination thereof, preferably a carbon-carbon double bond. Among these, the reactive additive preferably contains a carbon-carbon unsaturated bond in the form of a vinyl group and / or a (meth)acrylic group. Furthermore, the reactive additive preferably contains at least one active hydrogen reactive group selected from the group consisting of an epoxy group, a glycidyl group, and an isocyanate group, and more preferably contains an acrylic group and an isocyanate group.

[0241] Specific examples of reactive additives include compounds having a (meth)acrylic group and an epoxy group, such as methacryloyloxyglycidyl ether and acryloyloxyglycidyl ether; compounds having a (meth)acrylic group and an oxetane group, such as oxetane acrylate and oxetane methacrylate; compounds having a (meth)acrylic group and a lactone group, such as lactone acrylate and lactone methacrylate; compounds having a vinyl group and an oxazoline group, such as vinyloxazoline and isopropenyloxazoline; oligomers of compounds having a (meth)acrylic group and an isocyanate group, such as isocyanatomethyl acrylate, isocyanatomethyl methacrylate, 2-isocyanatoethyl acrylate, or 2-isocyanatoethyl methacrylate. Furthermore, compounds having a vinyl group, 1,2-vinylene, and an acid anhydride, such as methacrylic anhydride, acrylic anhydride, maleic anhydride, or vinylmaleic anhydride, can be mentioned. Among them, methacryloyloxy glycidyl ether, acryloyloxy glycidyl ether, isocyanate methyl acrylate, isocyanate methyl methacrylate, vinyloxazoline, 2-isocyanate ethyl acrylate, 2-isocyanate ethyl methacrylate or the above oligomers are preferred, and isocyanate methyl acrylate, 2-isocyanate ethyl acrylate or the above oligomers are particularly preferred.

[0242] Specifically, a compound represented by the following formula (Y) is preferred.

[0243]

[0244] [In formula (Y), n represents an integer of 1 to 10, R 1’ represents a divalent aliphatic or alicyclic hydrocarbon group having 2 to 20 carbon atoms, or a divalent aromatic hydrocarbon group having 5 to 20 carbon atoms. 2’ For example, one side is -NH- and the other side is >NC(=O)-R 3’ The group represented by R 3’ represents a hydroxyl group or a group having a carbon-carbon unsaturated bond.

[0245] R in formula (Y) 3’ At least 1 R 3’ is a group having a carbon-carbon unsaturated bond.]

[0246] Among the reactive additives represented by the above formula (Y), compounds represented by the following formula (YY) (hereinafter sometimes referred to as compound (YY)) are particularly preferred (wherein n has the same meaning as described above).

[0247]

[0248] As compound (YY), a commercially available product may be used as it is, or may be purified as needed and used. Examples of commercially available products include Laromer (registered trademark) LR-9000 (manufactured by BASF).

[0249] When the polarizing layer-forming composition contains a reactive additive, the content of the reactive additive is usually 0.01 to 10 parts by mass, preferably 0.1 to 5 parts by mass, based on 100 parts by mass of the liquid crystal compound.

[0250] (Protective layer lamination step)

[0251] During the protective layer lamination process, Figure 3 As shown in FIG. 3 (c), a protective layer 35 having a covered region 35a for covering the polarizing layer 21 and an exposed region 35b for exposing the polarizing layer 21 is laminated on the polarizing layer 21 of the laminated film 62 prepared in the preparation step. Thus, a laminated film 63 with a protective layer can be obtained. The exposed region 35b can be formed, for example, as an opening in the protective layer 35. When a liquid substance capable of reducing the content of the dichroic dye in the polarizing layer 21, described later, is brought into contact with the laminated film 63 with a protective layer, the covered region 35a can prevent the liquid substance from coming into contact with the polarizing layer 21. Meanwhile, the exposed region 35b of the protective layer 35 allows the liquid substance to come into contact with the polarizing layer 21.

[0252] As will be described later, if the polarizing layer 21 comes into contact with a liquid, the liquid will penetrate into the polarizing layer 21, causing the dichroic pigment to lose its function as a pigment. Therefore, the exposed area 35b is preferably formed corresponding to an area where the content of the dichroic pigment in the polarizing layer 21 is reduced. For example, when manufacturing Figure 1 In the case of the polarizing film 1 shown in (a) and (b), the shape of the second region 11b is preferably determined to correspond to the shape of the second region 11b. For example, if the top view shape of the second region 11b is a circle; an ellipse; an oblong; a polygon such as a triangle, square, rectangle, or rhombus; a line; a strip; or a wave, the exposed region 35b can be formed to correspond to one of these shapes.

[0253] For example, if the exposed area 35b is circular, its diameter is preferably 5 cm or less, more preferably 3 cm or less, and even more preferably 2 cm or less. If the exposed area 35b is elliptical or oblong, its major axis is preferably 5 cm or less, more preferably 3 cm or less, and even more preferably 2 cm or less. If the exposed area 35b is polygonal, the diameter of an imaginary circle drawn to inscribe the polygon is preferably 5 cm or less, more preferably 3 cm or less, and even more preferably 2 cm or less. As described later, the liquid substance penetrates the liquid crystal layer, so the size of the exposed area 35b may not be the same as that of the second area 11b, but may be slightly smaller than the second area 11b.

[0254] In addition, the covering region 35a of the protective layer 35 is preferably formed to correspond to a region where the content of the dichroic pigment in the polarizing layer 21 is not reduced. Figure 1 In the case of the polarizing film 1 shown in (a) and (b), it is preferable to determine the shape thereof in accordance with the shape of the first region 11 a.

[0255] As the protective layer 35, a product having an exposed area 35b formed on a sheet substrate can be used. The exposed area 35b can be formed by mechanically punching a predetermined portion of the sheet substrate using a punch, a cutting plotter, or a water jet, or by removing the predetermined portion of the sheet substrate using laser ablation, chemical dissolution, or the like.

[0256] The sheet-like substrate forming protective layer 35 is not particularly limited in material, as long as it is insoluble in the liquid material (described later) that reduces the dichroic pigment content in the liquid crystal layer upon contact, and is durable against removal of the liquid material and exposure to ultraviolet light after contact with the liquid material. The sheet-like substrate forming protective layer 35 can be formed, for example, from the same material as that used for substrate layer 13 described above. A resin substrate is particularly preferred, and a polyester resin such as polyethylene terephthalate is more preferred, as it easily suppresses deformation of the exposed area 35b (e.g., the opening) of protective layer 35.

[0257] The protective layer 35 preferably has an adhesive layer for bonding to the polarizing layer 21. In order to enable the protective layer 35 to be peeled off as described later, the adhesive layer is preferably peelable relative to the polarizing layer 21. The thickness of the protective layer 35 is usually 20 μm or more, preferably 30 μm or more, and usually 250 μm or less, preferably 200 μm or less.

[0258] (Decolorization process)

[0259] In the decolorization step, the protective layer-attached laminated film 63 obtained in the protective layer lamination step is brought into contact with a liquid capable of reducing the content of the dichroic pigment in the polarizing layer 21, thereby obtaining a decolorized laminated film 64 ( Figure 3(d)) The protective layer 35 of the protective layer-coated laminate film 63 includes a covered region 35a for covering the polarizing layer 21 and an exposed region 35b for exposing the polarizing layer 21. Therefore, the liquid substance can come into contact with the polarizing layer 21 in the exposed region 35b. This reduces the content of the dichroic pigment in the region of the polarizing layer 21 that comes into contact with the liquid substance.

[0260] The contact between the laminated film 63 with the protective layer and the liquid can be carried out by immersing the laminated film 63 with the protective layer in the liquid, coating, spraying, or dripping the liquid onto the laminated film 63 with the protective layer, etc., preferably by immersing the laminated film 63 with the protective layer in the liquid. Thus, in the polarizing layer 21, the surface of the polarizing layer 21 exposed from the exposed area 35b of the protective layer 35 comes into contact with the liquid and penetrates into the interior of the polarizing layer 21. Although the details are unclear, it can be considered as follows: the liquid that penetrates into the interior of the polarizing layer 21 decomposes the dichroic pigment in the polarizing layer 21, or reacts with the dichroic pigment, etc., thereby eliminating the function of the dichroic pigment as a pigment. Thus, in a part of the polarizing layer 21, a second region 11b is formed as a region having a lower content of dichroic pigment than other regions, and a decolorized laminated film 64 ( Figure 3 (d)).

[0261] In the area of ​​the polarizing layer 21 that is covered by the covered area 35a of the protective layer 35, the polarizing layer 21 is not in direct contact with the liquid substance. Therefore, the liquid substance is unlikely to penetrate into the polarizing layer 21, and the dichroic pigment is unlikely to disappear. In contrast, in the area of ​​the polarizing layer 21 that is exposed from the exposed area 35b of the protective layer 35, the polarizing layer 21 is in direct contact with the liquid substance. Therefore, the liquid substance easily penetrates into the polarizing layer 21, and the dichroic pigment easily disappears. Therefore, Figure 3 In the decolorized laminated film 64 shown in (d), the liquid crystal layer 11 can be formed in the region corresponding to the exposed region 35b of the polarizing layer 21 and having the second region 11b as a low polarization region having a lower content of dichroic dye than other regions.

[0262] As described above, by using the protective layer-attached laminated film 63 in which the exposed region 35b of the protective layer 35 is disposed in the region where the dichroic dye content is desired to be reduced in the polarizing layer 21, it is possible to form the liquid crystal layer 11 in which the dichroic dye content is reduced at the desired position in the polarizing layer 21. However, since the liquid material permeates into the interior of the polarizing layer 21 and thereby eliminates the function of the dichroic dye, it is preferable to adjust the thickness of the protective layer 35, the size of the exposed region 35b, the concentration of the liquid material, the immersion time of the protective layer-attached laminated film in the liquid material, and the amount of the liquid material applied, sprayed, or dripped onto the protective layer-attached laminated film 63 so as to prevent the liquid material from permeating into the region where the dichroic dye content does not need to be reduced and thereby reducing the dichroic dye content.

[0263] There are no particular limitations on the liquid material capable of reducing the content of the dichroic pigment in the polarizing layer 21, as long as it can reduce the content of the dichroic pigment. For example, peroxides (such as hydrogen peroxide and sodium percarbonate), chlorine compounds (such as sodium hypochlorite), acids (such as sulfuric acid, nitric acid, and hexafluorophosphoric acid), and alkalis (such as sodium hydroxide and potassium hydroxide) can be used as appropriate. Among them, acids such as sulfuric acid, nitric acid, and hexafluorophosphoric acid are preferred. These liquid materials can be used alone or in combination.

[0264] The contact conditions between the protective layer-attached laminated film 63 and the liquid can be appropriately selected based on the thickness of the polarizing layer 21 and the range within which the dichroic pigment content is reduced. The concentration of the liquid is preferably, for example, 20 to 80% by mass, more preferably 30 to 70% by mass. Furthermore, the temperature of the liquid is preferably 50 to 150°C, more preferably 80 to 120°C.

[0265] The decolorization step preferably includes a first washing step in which the protective layer-attached laminated film 63 is brought into contact with the liquid to form a region having a lower dichroic pigment content than other regions in a portion of the polarizing layer 21, and then the liquid is washed away. The first washing step can be performed using an organic solvent such as water or alcohol.

[0266] (Peeling process)

[0267] In the peeling step, the protective layer 35 is peeled off from the decolorized laminated film 64 obtained in the decolorization step. Thus, a polarizing film 1 ( Figure 1 (a) and (b)).

[0268] For Figure 1The polarizing film 1 shown in (b) can also be used after the base layer 13 is further peeled off. In this case, the orientation layer 12 can also be peeled off together with the base layer 13. For example, the base layer 13 can be peeled off after the liquid crystal layer 11 of the polarizing film 1 is attached to a component forming a display device, a phase difference layer, etc.

[0269] (Method for continuously producing polarizing film)

[0270] The manufacturing method of the polarizing film 1 is preferably capable of being continuously manufactured in a roll-to-roll form. In this case, a laminated film that has been wound into a roll can be prepared in the preparation process, and the laminated film can be unwound while being conveyed, and the protective layer lamination process, the decolorization process, and the stripping process can be continuously performed. In the protective layer lamination process, the protective layer that has been wound into a roll can be unwound while being conveyed, and the protective layer can be attached to the laminated film to obtain a laminated film with a protective layer. In the decolorization process, the laminated film with a protective layer can be continuously conveyed while passing the laminated film with a protective layer through a liquid bath filled with a liquid, or the laminated film with a protective layer can be continuously conveyed while being coated, sprayed or dripped with a liquid to obtain a decolorized laminated film. In the stripping process, the protective layer can be continuously stripped from the decolorized laminated film, and the polarizing film can be wound into a roll to make a roll. The polarizing film continuously manufactured as described above can, for example, have a length of more than 10m.

[0271] Furthermore, when the preparation step includes an alignment layer forming step, the alignment layer can be formed by continuously coating the alignment layer forming composition onto the substrate layer using a coating apparatus while unwinding the substrate layer wound into a roll. When the preparation step includes a polarizing layer forming step, the polarizing layer can be formed by coating the polarizing layer forming composition onto the side of the substrate layer with the alignment layer formed thereon while continuously conveying the substrate layer with the alignment layer.

[0272] The polarizing film 1 manufactured using this first manufacturing method can reduce the difference in thickness between the first region 11a and the second region 11b to, for example, 2 μm or less, thereby achieving a polarizing film 1 without any height difference. This allows the polarizing film 1 to be laminated without introducing air bubbles even when another film is bonded to the polarizing layer 21 using an adhesive or the like.

[0273] <Method for Manufacturing Polarizing Film (Second Manufacturing Method)>

[0274] The polarizing film 1 can be manufactured by the second manufacturing method described below in addition to the first manufacturing method described above. Figure 4 To express Figure 1(b) is a schematic cross-sectional view of an example of a liquid material contact step in the method for manufacturing the polarizing film 1. The second method for manufacturing the polarizing film 1 includes the following steps:

[0275] Preparation step: preparing a laminated film 62 ( Figure 3 (b)); and

[0276] In the liquid material contact step, a portion of the polarizing layer 21 of the laminated film 62 is brought into contact with a liquid material capable of reducing the content of the dichroic pigment in the polarizing layer 21, thereby reducing the content of the dichroic pigment in the portion ( Figure 4 ),

[0277] Thus, it is possible to produce Figure 1 Polarizing films 1 shown in (a) and (b).

[0278] The preparation step in the second manufacturing method is based on Figure 3 The preparation steps in the first manufacturing method described in (a) and (b) are the same. Through this preparation step, the laminated film 62 including the polarizing layer 21 is prepared.

[0279] In the second manufacturing method, a portion of the polarizing layer 21 on the laminated film 62 is brought into contact with the liquid substance ( Figure 4 The liquid used at this time is a substance that can reduce the content of the dichroic pigment in a part of the polarizing layer 21, and the same liquid as that used in the decolorization step in the first manufacturing method can be used. As a method for bringing a part of the polarizing layer 21 into contact with the liquid, for example, the following can be mentioned. Figure 4 As shown in the figure, a liquid is dripped into the partial area and applied, such as the so-called inkjet method. By contacting the polarizing layer 21 with the liquid, the liquid penetrates into a partial area of ​​the polarizing layer 21, reducing the content of the dichroic pigment and forming a low polarization area.

[0280] The second manufacturing method preferably includes a second washing step, wherein the polarizing layer 21 is brought into contact with the liquid substance and then the liquid substance on the polarizing layer 21 is washed away. The second washing step can be performed using an organic solvent such as water or alcohol used in the first washing step of the first manufacturing method. Figure 1 (b) The polarizing film 1 shown.

[0281] Regarding the second manufacturing method, similar to the first manufacturing method, the polarizing film 1 can be continuously manufactured using, for example, a roll-to-roll process. In this case, a laminated film wound into a roll can be prepared in the preparation step, and the laminated film can be unwound while being conveyed, and the liquid contact step can be continuously performed. In the liquid contact step, the liquid can be dripped and applied while the laminated film is continuously conveyed to obtain a polarizing film, and the obtained polarizing film can be wound into a roll to form a roll body. The polarizing film continuously manufactured as described above can have a length of, for example, 10 meters or more.

[0282] Furthermore, when the preparation step includes an alignment layer forming step, the alignment layer can be formed by continuously coating the alignment layer forming composition onto the substrate layer using a coating apparatus while unwinding the substrate layer wound into a roll. When the preparation step includes a polarizing layer forming step, the polarizing layer can be formed by coating the polarizing layer forming composition onto the side of the substrate layer with the alignment layer formed thereon while continuously conveying the substrate layer with the alignment layer.

[0283] The second manufacturing method can also reduce the difference in thickness between the first region 11a and the second region 11b to, for example, 2 μm or less, thereby obtaining a polarizing film 1 without unevenness. This allows lamination without introducing air bubbles even when another film is bonded to the polarizing layer 21 using an adhesive or the like.

[0284] <Method for Manufacturing Circularly Polarizing Plate>

[0285] The circularly polarizing plate can be manufactured by laminating a polarizing film 1 with a phase difference layer. As described above, when the polarizing film is a continuously manufactured long strip polarizing film with a length of 10 m or more, it is preferred to use a long strip phase difference layer with a length of 10 m or more as the phase difference layer, and to laminate the long strip polarizing film and the long strip phase difference layer while continuously conveying the two, thereby forming a long strip laminate. In this case, it is preferred to apply an adhesive or a bonding agent to at least one of the long strip polarizing film and the long strip phase difference layer, and then laminate the two.

[0286] In order to attach the polarizing film to a display device of a specified size, etc., the method for manufacturing a circularly polarizing plate may include a step of cutting a long strip laminated body obtained by laminating a long strip polarizing film and a long strip phase difference layer into single pieces of a specified size. In the cutting step, the long strip laminated body is preferably cut along at least one of the length direction and the width direction of the long strip laminated body. In this case, the cutting position in the long strip laminated body is preferably determined so that the second region 11b of the liquid crystal layer 11 is arranged at a specified position in the cut single piece.

[0287] Example

[0288] The present invention will be described in more detail based on examples, but the present invention is not limited to these examples.

[0289] [Visibility Corrected Polarization (Py) and Visibility Corrected Transmittance (Ty)]

[0290] (Preparation of Evaluation Samples)

[0291] Prepare the alignment layer composition and polarizing layer composition used in each of the Examples, Comparative Examples, and Reference Examples. Also, prepare a 40 mm x 40 mm film cut from the same film used as the substrate layer in each of the Examples, Comparative Examples, and Reference Examples to serve as the substrate layer for the evaluation samples. Using these, in Examples 1 and 2, the Comparative Examples, and the Reference Examples, no protective layer was used. In Example 3, the entire surface of the polarizing layer was exposed to the solution instead of dripping the solution onto the polarizing layer. The evaluation samples were obtained by following the same procedures as for the polarizing films of the Examples, Comparative Examples, and Reference Examples.

[0292] (Visibility Corrected Polarization (Py) and Visibility Corrected Transmittance (Ty))

[0293] For the evaluation samples, the visibility-corrected single transmittance (Ty) and the visibility-corrected polarization (Py) were calculated using the following steps. In the wavelength range of 380 nm to 780 nm, a device consisting of a folding device with a polarizer installed on a spectrophotometer (UV-3150 manufactured by Shimadzu Corporation) was used to measure the transmittance (T1) in the transmission axis direction and the transmittance (T2) in the absorption axis direction using the double-beam method. For the folding device, a mesh that blocks 50% of the light is set on the reference side. The transmittance and polarization at each wavelength are calculated using the following (Formula 1) and (Formula 2), and then, using the 2-degree field of view (light source C) of JIS Z 8701, visibility correction is performed to calculate the visibility-corrected transmittance (Ty) and visibility-corrected polarization (Py).

[0294] Polarization degree [%]={(T1-T2) / (T1+T2)}×100 (Formula 1)

[0295] Single body transmittance [%] = (T1 + T2) / 2 (Formula 2)

[0296] [Example 1]

[0297] (Manufacturing of Alignment Layer-Forming Composition)

[0298] The following components were mixed, and the obtained mixture was stirred at 80° C. for 1 hour to obtain a composition for forming an alignment layer, which is a composition for forming a photo-alignment film.

[0299] 2 parts of the polymer with photoreactive groups shown below

[0300]

[0301] Solvent: 98 parts of o-xylene

[0302] (Manufacturing of Polarizing Layer-Forming Composition)

[0303] The following components were mixed and stirred at 80° C. for 1 hour to obtain a polarizing layer-forming composition. As the dichroic dye, an azo dye described in Examples of JP-A-2013-101328 was used.

[0304] 75 parts of the polymerizable liquid crystal compound represented by formula (1-6)

[0305]

[0306] 25 parts of the polymerizable liquid crystal compound represented by formula (1-7)

[0307]

[0308] 2.8 parts of the dichroic pigment (1) shown below

[0309]

[0310] 2.8 parts of the dichroic pigment (2) shown below

[0311]

[0312] 2.8 parts of the dichroic pigment (3) shown below

[0313]

[0314] 6 parts of the polymerization initiator shown below

[0315] 2-Dimethylamino-2-benzyl-1-(4-morpholinophenyl)butan-1-one (Irgacure 369; manufactured by Ciba Specialty Chemicals, Inc.)

[0316] 1.2 parts of the leveling agent shown below

[0317] Polyacrylate compound (BYK-361N; manufactured by BYK-Chemie)

[0318] 250 parts of the solvent shown below

[0319] Cyclopentanone

[0320] (Manufacturing of polarizing films)

[0321] A triacetylcellulose film (KC4UY-TAC, 40 μm thick, manufactured by Konica Minolta) serving as a substrate layer was cut into 20×20 mm pieces and its surface was subjected to a corona treatment (AGF-B10, manufactured by Kasuga Electric Co., Ltd.). The composition for forming an alignment layer was applied to the corona-treated film surface using a bar coater and then dried in a drying oven set to 120°C for 1 minute to obtain an alignment layer coating layer. A polarized UV light irradiation device (SPOT CURE SP-7; manufactured by USHIO INC.) was used to irradiate the film at 50 mJ / cm 2 The polarized UV light was irradiated onto the coating layer for the alignment layer by using a rod coater to form an alignment layer. The polarizing layer-forming composition was applied to the alignment layer obtained, and then dried in a drying oven set to 110°C for 1 minute. Then, ultraviolet light (wavelength: 365nm, cumulative light intensity at wavelength: 1000mJ / cm2 at 365nm) was irradiated using a high-pressure mercury lamp (Unicure VB-15201BY-A, manufactured by USHIO INC.) under a nitrogen atmosphere. 2 ), thereby obtaining a polarizing layer in which the liquid crystal compound and the dichroic dye were oriented. A protective layer (AY-638 manufactured by Fujimori Industries, Ltd., a 15 μm thick adhesive layer provided on a 38 μm thick polyester film) was laminated to the polarizing layer, with openings formed therein using a punch. The film was then immersed in a 50 wt% solution of diphenyl 4-thiophenoxyphenyl sulfonium hexafluorophosphate (CPI-100P manufactured by San-Apro Ltd.) in propylene carbonate at 120°C for 60 seconds. The protective layer was then peeled off to obtain a polarizing film.

[0322] Visual inspection of the resulting polarizing film revealed a circular region (low polarization region) where the polarizing layer was absent, indicating that a polarizing film having both polarizing and low polarization regions was obtained. Furthermore, evaluation samples were prepared using the aforementioned steps, and their visibility-corrected transmittance (Ty) and visibility-corrected polarization (Py) were calculated. The results are shown in Table 1.

[0323] [Example 2]

[0324] A polarizing film was obtained by the same procedures as in Example 1, except that a hard-coated surface of a quarter-wave plate (ZEONOR FILM, ZEON Corporation, Japan, in-plane retardation value Ro: 138 nm), a uniaxially stretched film of a cyclic olefin resin, was used as the substrate layer instead of the triacetylcellulose film. The film was laminated so that the slow axis and the absorption axis of the polarizing layer were at 45°. Furthermore, evaluation samples were prepared using the above-described procedures, and their visibility-corrected transmittance (Ty) and visibility-corrected polarization (Py) were calculated. The results are shown in Table 1.

[0325] [Example 3]

[0326] A polarizing film was obtained in the same manner as in Example 1, except that a 50 wt% solution of diphenyl 4-phenylthiophenylsulfonium hexafluorophosphate (CPI-100P manufactured by San-Apro Ltd.) in propylene carbonate was locally added dropwise onto the polarizing layer using a dropper instead of a punch to form openings in the protective layer. Furthermore, evaluation samples were prepared using the above-described procedures, and their visibility-corrected transmittance (Ty) and visibility-corrected polarization (Py) were calculated. The results are shown in Table 1.

[0327] [Comparative Example]

[0328] A polarizing film was obtained by the same procedure as in Example 1, except that methanol was used at room temperature instead of a 50 wt% solution of diphenyl 4-phenylthiophenylsulfonium hexafluorophosphate (CPI-100P manufactured by San-Apro Ltd.) in propylene carbonate. Visual inspection of the resulting polarizing film revealed no areas lacking a polarizing layer, indicating that a polarizing film having both a polarizing region and a low-polarization region was not obtained. Furthermore, evaluation samples were prepared using the above procedure, and their visibility-corrected transmittance (Ty) and visibility-corrected polarization (Py) were calculated. The results are shown in Table 1.

[0329] [Reference Example]

[0330] A polarizing film was obtained in the same manner as in Example 1, except that a 50 wt% solution of diphenyl 4-phenylthiophenylsulfonium hexafluorophosphate (CPI-100P, manufactured by San-Apro Ltd.) in propylene carbonate was not used. Visual inspection of the resulting polarizing film revealed no areas lacking a polarizing layer, indicating that a polarizing film having both a polarizing region and a low-polarization region was not obtained. Evaluation samples were prepared using the aforementioned procedures, and their visibility-corrected transmittance (Ty) and visibility-corrected polarization (Py) were calculated. The results are shown in Table 1.

[0331] It should be noted that the values ​​of the visibility-corrected transmittance (Ty) and the visibility-corrected polarization (Py) measured in each of the embodiments, comparative examples, and reference examples shown in Table 1 are values ​​including the values ​​of the visibility-corrected transmittance (Ty) and the visibility-corrected polarization (Py) of the substrate layer. The visibility-corrected transmittance (Ty) of the substrate layer alone is 92%, and the value of the visibility-corrected polarization (Py) of the substrate layer is 0%. Therefore, it is considered that in each of the embodiments, comparative examples, and reference examples shown in Table 1, when the substrate layer is removed, the value of the visibility-corrected transmittance (Ty) is greater than the value shown in Table 1, and the value of the visibility-corrected polarization (Py) is the same as the value shown in Table 1.

[0332] [Table 1]

[0333]

[0334] Description of Reference Numerals

[0335] 1 polarizing film

[0336] 5a~5c circular polarizing plates

[0337] 11 Liquid crystal layer

[0338] 11a Area 1

[0339] 11b Area 2

[0340] 12 Orientation layer

[0341] 13. Base material layer

[0342] 15 Phase difference layer

[0343] 21 polarizing layer

[0344] 35 protective layer

[0345] 35a covered area

[0346] 35b exposed area

[0347] 61. Substrate layer with orientation layer

[0348] 62 laminated film

[0349] 63 Laminated film with protective layer

[0350] 64 Decolorized laminated film.

Claims

1. Polarizing film, which is a polarizing film with a liquid crystal layer, The liquid crystal layer is a cured film containing a liquid crystal compound and has at least two regions distinguished by a value of a visibility-corrected polarization degree. The contents of the dichroic pigment in the at least two regions are different from each other, The liquid crystal layer includes a first region containing a dichroic dye and a second region having a lower content of the dichroic dye than the first region. The difference between the thickness of the first region and the thickness of the second region is 0.5 μm or less. The dichroic dye is an azo dye.

2. The polarizing film according to claim 1, further comprising: a substrate layer, and an orientation layer laminated on at least one side of the substrate layer, The liquid crystal layer is stacked on the alignment layer.

3. The polarizing film according to claim 2, wherein The alignment layer includes a photo-alignment polymer.

4. The polarizing film according to any one of claims 1 to 3, wherein The liquid crystal compound includes a polymerizable liquid crystal compound.

5. The polarizing film according to any one of claims 1 to 3, wherein The visibility correction polarization degree of the first region is 90% or more, The visibility-corrected polarization degree of the second region is 10% or less.

6. The polarizing film according to any one of claims 1 to 3, wherein The visibility correction single unit transmittance of the first region is 35% or more, The visibility correction single unit transmittance of the second region is 80% or more.

7. The polarizing film according to claim 5, wherein The top view shape of the second region is circular, elliptical, oblong or polygonal, When the second region is circular, its diameter is less than 5 cm. When the second region is elliptical or oblong, the major diameter is 5 cm or less. When the second region is a polygon, the diameter of an imaginary circle drawn so as to inscribe the polygon is 5 cm or less.

8. The polarizing film according to claim 5, wherein The first region shows a Bragg peak in X-ray diffraction measurement.

9. The polarizing film according to any one of claims 1 to 3, wherein The second region contains a phosphoric acid component.

10. The polarizing film according to any one of claims 1 to 3, further comprising a substrate layer. The base material layer functions as a quarter-wave plate.

11. The polarizing film according to any one of claims 1 to 3, wherein The length of the polarizing film is greater than 10 m. 12 . A circularly polarizing plate comprising a laminate of the polarizing film according to claim 1 and a phase difference layer having a quarter wavelength plate function.

13. A method for producing a polarizing film, comprising the following steps: a preparation step of preparing a laminated film having a polarizing layer containing a liquid crystal compound and a dichroic dye on at least one side of a substrate layer; and a liquid material contact step of contacting a portion of the polarizing layer of the laminated film with a liquid material capable of reducing the content of a dichroic pigment in the polarizing layer, thereby reducing the content of the dichroic pigment in the portion of the polarizing layer to form a first region and a second region having different contents of the dichroic pigment; in, The polarizing layer is a cured film, The difference between the thickness of the first region and the thickness of the second region is 0.5 μm or less. The dichroic dye is an azo dye.

14. The method for producing a polarizing film according to claim 13, wherein: The liquid material contacting step includes the following steps: a protective layer laminating step of laminating a protective layer having a covered region for covering the polarizing layer and an exposed region for exposing the polarizing layer on the polarizing layer of the laminated film prepared in the preparing step, thereby obtaining a laminated film with a protective layer; a decolorization step of contacting the laminated film with the protective layer with a liquid capable of reducing the content of the dichroic dye in the polarizing layer, thereby obtaining a decolorized laminated film having a reduced content of the dichroic dye in a portion of the polarizing layer; and The peeling step is to peel the protective layer from the decolorizing laminated film.

15. The method for producing a polarizing film according to claim 14, wherein: The exposed area in the protective layer has a top view shape of a circle, an ellipse, an oblong or a polygon. The diameter of the exposed area in the case of a circle is 5 cm or less, When the exposed area is elliptical or oblong, the major diameter is less than 5 cm. When the exposed area is a polygon, the diameter of an imaginary circle drawn so as to inscribe the polygon is 5 cm or less.

16. The method for producing a polarizing film according to any one of claims 13 to 15, wherein: The preparation process includes the following steps: an alignment layer forming step of applying an alignment layer forming composition on one side of the substrate layer to form an alignment layer; and In the polarizing layer forming step, a polarizing layer-forming composition containing the liquid crystal compound and the dichroic dye is applied to the surface of the substrate layer on which the alignment layer is formed, thereby forming the polarizing layer.

17. The method for producing a polarizing film according to claim 16, wherein: The alignment layer-forming composition includes a photo-alignment polymer, In the alignment layer forming step, the alignment layer is formed by irradiating a coating layer for an alignment layer formed by applying the alignment layer forming composition with polarized light.

18. The method for producing a polarizing film according to claim 16, wherein: The liquid crystal compound is a polymerizable liquid crystal compound, In the polarizing layer forming step, the polarizing layer is formed by irradiating a polarizing layer coating layer formed by applying the polarizing layer forming composition with active energy rays.

19. The method for producing a polarizing film according to any one of claims 13 to 15, wherein The length of the polarizing film is greater than 10 m.

20. The method for producing a polarizing film according to claim 13, wherein: The liquid is an acid, The acid is hexafluorophosphoric acid.

21. A method for manufacturing a circularly polarizing plate, comprising the following steps: The retardation layer lamination step comprises laminating the polarizing film produced by the method for producing a polarizing film according to any one of claims 13 to 20 and the retardation layer having a quarter wavelength plate function.

22. The method for manufacturing a circularly polarizing plate according to claim 21, wherein: The polarizing film is a long strip polarizing film with a length of more than 10m. The phase difference layer is a long strip phase difference layer with a length of more than 10m. In the phase difference layer lamination step, the long strip polarizing film and the long strip phase difference layer are laminated to form a long strip laminate. The manufacturing method further comprises a cutting step of cutting the long-length laminate into individual pieces.

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