Laminate film and method for manufacturing polarizing plate with retardation layer

Abstract

To provide a laminate film having a liquid crystal alignment solidification layer excellent in appearance which is suitable for manufacture of a polarizing plate with a retardation layer, and a method for manufacturing a polarizing plate with a retardation layer using the laminate film.SOLUTION: A laminate film includes a stretched film which is stretched in a predetermined direction, and a liquid crystal alignment solidification layer. The stretched film includes a film base material, and an alignment film. The liquid crystal alignment solidification layer is laminated on the surface of the alignment film. The liquid crystal alignment solidification layer contains a rod-like liquid crystal compound which is homogeneously aligned. The alignment film contains a specific cellulose-based resin. The thickness of the alignment film is 0.1 μm to 10 μm. The slow axis direction of the liquid crystal alignment solidification layer and the stretching direction of the stretched film cross each other.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a method for producing a laminate film and a polarizing plate with a retardation layer. [Background technology]

[0002] In general, in order to ensure optical characteristics suitable for a particular application, various retardation layer-attached polarizing plates that combine a polarizer and a retardation film are used in image display devices. As a retardation film used in such retardation layer-attached polarizing plates, a liquid crystal alignment fixed layer in which liquid crystal compounds are aligned in a predetermined direction and the alignment state is fixed is known. As a method for preparing such a liquid crystal alignment solidified layer, for example, a method has been proposed in which a resin film is stretched to exert an alignment control force in the stretching direction, a composition containing a liquid crystal compound is then applied to the stretched film to homogeneously align the liquid crystal compound in the stretching direction of the stretched film, and then the alignment state of the liquid crystal compound is fixed (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-160359 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, the method for preparing a liquid crystal alignment solidified layer described in Patent Document 1 may result in lattice-like unevenness (hereinafter referred to as lattice unevenness) in the obtained liquid crystal alignment solidified layer, making it difficult to realize a liquid crystal alignment solidified layer with excellent appearance. In addition, in the preparation method of the liquid crystal alignment solidified layer, a resin film is generally stretched in a direction substantially parallel to the longitudinal direction, and a composition containing a liquid crystal compound is applied to the obtained stretched film. Therefore, the orientation direction of the liquid crystal compound in the liquid crystal alignment solidified layer is substantially parallel to the stretching direction of the stretched film, and as a result, the slow axis direction of the liquid crystal alignment solidified layer is substantially parallel to the longitudinal direction of the stretched film. When such a liquid crystal alignment solidified layer is applied to a retardation layer-attached polarizing plate, it is necessary to cut out a chip having an external shape similar to that of a polarizer from the liquid crystal alignment solidified layer by adjusting the angle so that the slow axis direction is at a desired angle with the absorption axis direction when attached to the polarizer, and attach it to the polarizer. However, in such a method, the manufacture of the retardation layer-attached polarizing plate is complicated, so that an improvement in the manufacturing efficiency of the retardation layer-attached polarizing plate is desired. Furthermore, it is also considered to apply an obliquely stretched film stretched in a direction oblique to the longitudinal direction to the preparation of a liquid crystal alignment solidified layer. However, since the preparation of the obliquely stretched film is complicated compared with the preparation of a stretched film in which the longitudinal direction and the stretching direction are substantially parallel, it is difficult to sufficiently improve the production efficiency of a polarizing plate with a retardation layer even if an obliquely stretched film is used. The present invention has been made to solve the above-mentioned problems in the conventional art, and its main object is to provide a laminate film having a liquid crystal alignment solidified layer with excellent appearance, which is suitable for producing a polarizing plate with a retardation layer, and a method for producing a polarizing plate with a retardation layer using the laminate film. [Means for solving the problem]

[0005] [1] A laminated film according to an embodiment of the present invention includes a stretched film stretched in a predetermined direction and a liquid crystal alignment solidified layer. The stretched film includes a film substrate and an alignment film. The liquid crystal alignment solidified layer is laminated on the surface of the alignment film. The liquid crystal alignment solidified layer contains rod-shaped liquid crystal compounds that are homogeneously aligned. The alignment film contains a cellulose-based resin having a constitutional unit represented by the following general formula (1). The alignment film has a thickness of 0.1 μm to 10 μm. The slow axis direction of the liquid crystal alignment solidified layer and the stretching direction of the stretched film intersect with each other. [ka] (In the above general formula (1), R 1 ~R 6 R each independently represents a hydrogen atom, a methylcarbonyl group represented by the following general formula (2), or an atomic group represented by the following general formula (3). 1 ~R 6 At least one of the groups represents an atomic group represented by the following general formula (3): [ka] [ka] (In the above general formula (3), R 7 represents a hydrocarbon group having 2 or more carbon atoms. [2] In the laminated film described in [1] above, R 7 may represent an alkyl group having 2 or more carbon atoms. [3] In the laminated film described in [1] above, R 7 may represent an ethyl group or a propyl group. [4] In the laminate film according to any one of [1] to [3] above, R 1 ~R 6 One or more and three or less of the above may represent the atomic group represented by the above general formula (3). [5] In the laminate film described in any one of [1] to [4] above, the angle between the stretching direction of the stretched film and the slow axis direction of the liquid crystal alignment solidified layer may be more than 5° and not more than 20°. [6] In the laminate film according to any one of [1] to [5] above, the alignment film may further contain a sucrose derivative having a molecular weight of 1,000 or less. [7] A method for producing a polarizing plate with a retardation layer according to another aspect of the present invention includes the steps of: preparing a first stretched film having a long shape and including a first film substrate and a first alignment film; forming a first liquid crystal alignment solidified layer containing homogeneously aligned rod-shaped liquid crystal compounds on a surface of the first alignment film; and preparing a second stretched film having a long shape and including a second film substrate and a second alignment film; The method includes the steps of forming a second liquid crystal alignment solidified layer containing homogeneously aligned rod-shaped liquid crystal compounds on the surface of the second alignment film; laminating the first liquid crystal alignment solidified layer and the second liquid crystal alignment solidified layer; peeling the first stretched film from the first liquid crystal alignment solidified layer laminated to the second liquid crystal alignment solidified layer; and laminating a long-shaped polarizer on the surface of the first liquid crystal alignment solidified layer opposite to the second liquid crystal alignment solidified layer. Each of the first alignment film and the second alignment film contains a cellulose resin having a structural unit represented by the above general formula (1). Each of the first alignment film and the second alignment film has a thickness of 0.1 μm to 10 μm. The stretching direction of the first stretched film is substantially parallel to the longitudinal direction of the first stretched film, and the stretching direction of the second stretched film is substantially perpendicular to the longitudinal direction of the second stretched film. The slow axis direction of the first liquid crystal alignment solidified layer and the stretching direction of the first stretched film intersect with each other. The slow axis direction of the second liquid crystal alignment solidified layer and the stretching direction of the second stretched film intersect with each other. Effect of the Invention

[0006] According to an embodiment of the present invention, it is possible to realize a laminate film having a liquid crystal alignment solidified layer with excellent appearance, and suitable for producing a retardation layer-attached polarizing plate. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a schematic cross-sectional view of a laminated film according to one embodiment of the present invention. [Diagram 2] FIG. 2 is a schematic plan view of the laminated film of FIG. [Diagram 3] FIG. 3 is a schematic cross-sectional view of a first laminate film and a second laminate film used in a method for producing a retardation layer-attached polarizing plate according to another aspect of the present invention. [Figure 4] FIG. 4 is a schematic plan view of the first laminate film and the second laminate film of FIG. [Diagram 5] FIG. 5 is a schematic cross-sectional view of a laminated phase difference film in which the first laminate film and the second laminate film in FIG. 4 are laminated together. [Figure 6] FIG. 6 is a schematic plan view of the layered phase difference film of FIG. [Figure 7] FIG. 7 is a schematic cross-sectional view of a retardation layer-attached polarizing plate in which the laminated retardation film of FIG. 5 is attached to a polarizing plate. [Figure 8] FIG. 8 is a schematic plan view of the retardation layer-attached polarizing plate of FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Representative embodiments of the present invention will be described below, but the present invention is not limited to these embodiments. Note that the drawings are drawn typically or conceptually for ease of viewing and understanding, and the length, width, shape, size, ratio, direction, number, etc. may differ from the actual ones, and there may be no correspondence between the drawings.

[0009] (Definition of terms and symbols) The definitions of terms and symbols used in this specification are as follows. (1) Refractive index (nx, ny, nz) "nx" is the refractive index in the direction in which the in-plane refractive index is maximum (i.e., the slow axis direction), "ny" is the refractive index in the direction perpendicular to the slow axis in the plane (i.e., the fast axis direction), and "nz" is the refractive index in the thickness direction. (2) In-plane phase difference (Re) "Re(λ)" is the in-plane retardation measured with light of wavelength λ nm at 23° C. For example, "Re(550)" is the in-plane retardation measured with light of wavelength 550 nm at 23° C. Re(λ) is calculated by the formula: Re(λ)=(nx-ny)×d, where d(nm) is the thickness of the layer (film). (3) Retardation in the thickness direction (Rth) "Rth(λ)" is the retardation in the thickness direction measured with light of wavelength λ nm at 23° C. For example, "Rth(550)" is the retardation in the thickness direction measured with light of wavelength 550 nm at 23° C. Rth(λ) is calculated by the formula: Rth(λ)=(nx-nz)×d, where d(nm) is the thickness of the layer (film). (4) Nz coefficient The Nz coefficient is calculated by Nz=Rth / Re. (5) Substantially parallel or perpendicular The expressions "substantially orthogonal" and "approximately orthogonal" include the case where the angle between two directions is 90°±1°, and the expressions "substantially parallel" and "approximately parallel" include the case where the angle between two directions is 0°±1°. Furthermore, when simply referring to "orthogonal" or "parallel" in this specification, it is understood that this includes the state of being substantially orthogonal or substantially parallel. In addition, "intersect without being substantially perpendicular" means that the angle between the two directions is neither substantially perpendicular nor substantially parallel. More specifically, the expression "intersect without being substantially perpendicular" includes cases where the angle between the two directions is greater than 1° and less than 89°. (6)Angle When angles are referred to in this specification, unless otherwise specified, the angles include both clockwise and counterclockwise angles relative to a reference direction. Thus, for example, "45°" means ±45°.

[0010] A. Overall structure of laminated film FIG. 1 is a schematic cross-sectional view of a laminated film according to one embodiment of the present invention. The laminated film 100 in the illustrated example includes a stretched film 1 stretched in a predetermined direction, and a liquid crystal alignment solidified layer 2. The stretched film 1 includes a film substrate 11 and an alignment film 12. The alignment film 12 is typically disposed on one surface in the thickness direction of the film substrate 11. The alignment film 12 has a thickness of 0.1 μm to 10 μm. The alignment film 12 contains a cellulose-based resin having a constitutional unit represented by the following general formula (1). [ka] (In the above general formula (1), R 1 ~R 6 R each independently represents a hydrogen atom, a methylcarbonyl group represented by the following general formula (2), or an atomic group represented by the following general formula (3). 1 ~R 6 At least one of the groups represents an atomic group represented by the following general formula (3). [ka] [ka] (In the above general formula (3), R 7 represents a hydrocarbon group having 2 or more carbon atoms. The liquid crystal alignment solidified layer 2 is laminated on the surface of the alignment film 12. The liquid crystal alignment solidified layer 2 contains rod-shaped liquid crystal compounds that are homogeneously aligned. In this specification, the term "alignment solidified layer" refers to a layer in which liquid crystal compounds are aligned in a predetermined direction within the layer and the alignment state is fixed. The term "alignment solidified layer" is a concept that includes an alignment solidified layer obtained by hardening a liquid crystal monomer as described below. The liquid crystal alignment solidified layer 2 has an in-plane retardation. As shown in FIG. 2, the stretching direction X of the stretched film and the slow axis direction (direction in which the slow axis extends) Y of the liquid crystal alignment solidified layer intersect with each other. The present inventors have found that the material and thickness of the alignment film affect the occurrence of lattice unevenness in the liquid crystal alignment solidified layer. As a result of intensively studying the configuration of the alignment film, it has been found that the alignment film contains a specific cellulose-based resin, and the alignment film is sufficiently thinned, so that the lattice unevenness in the liquid crystal alignment solidified layer can be suppressed. More specifically, since the alignment film contains a cellulose-based resin having a constitutional unit represented by the above general formula (1) and the thickness of the alignment film is 10 μm or less, the lattice unevenness in the liquid crystal alignment solidified layer can be suppressed, and a liquid crystal alignment solidified layer having an excellent appearance can be realized. In addition, the slow axis direction of the liquid crystal alignment solidified layer formed on the surface of such an alignment film crosses the stretching direction of the stretched film. This phenomenon is presumably caused by the atomic group represented by the above general formula (3) being misaligned with respect to the cellulose main skeleton, and the rod-shaped liquid crystal compound interacting with the atomic group and being aligned. However, such a presumption does not restrict the embodiment and the mechanism of the present invention.

[0011] Such a laminated film can be suitably applied to the manufacture of a retardation layer-attached polarizing plate. More specifically, a long laminated film and a long polarizing plate are prepared, their long directions are aligned, and the liquid crystal alignment solidified layer and the polarizing plate are laminated together to manufacture a retardation layer-attached polarizing plate in which the slow axis direction of the liquid crystal alignment solidified layer and the absorption axis direction (the direction in which the absorption axis extends) of the polarizing plate are not substantially perpendicular to each other. In this specification, the term "long" refers to an elongated shape in which the length is sufficiently longer than the width, and includes, for example, an elongated shape in which the length is 10 times or more, preferably 20 times or more, the width. Each of the long laminate film and the polarizer can be wound into a roll. Therefore, a roll-to-roll method can be adopted for bonding the liquid crystal alignment solidified layer and the polarizer, and the production efficiency of the retardation layer-attached polarizing plate can be improved.

[0012] When the laminated film 100 has a long shape, the stretching direction X of the stretched film 1 may be substantially parallel to the long dimension direction of the laminated film 100, or may be substantially perpendicular to the long dimension direction of the laminated film 100. In the illustrated example, the stretching direction X of the stretched film 1 is substantially parallel to the long dimension direction of the laminated film 100. When the laminated film 100 has a long shape, the slow axis direction Y of the liquid crystal alignment solidified layer 2 typically intersects with the long direction of the stretched film 1 without being substantially perpendicular thereto.

[0013] In the laminated film 100, the angle between the stretching direction X of the stretched film 1 and the slow axis direction Y of the liquid crystal alignment solidified layer 2 exceeds, for example, 1°, preferably exceeds 5°, and more preferably exceeds 10°. Meanwhile, in the laminated film 100, the angle between the stretching direction X of the stretched film 1 and the slow axis direction of the liquid crystal alignment solidified layer 2 is, for example, 30° or less, preferably 20° or less. When the stretching direction of the stretched film and the slow axis direction of the liquid crystal alignment solidified layer form such an angle, in a retardation layer-attached polarizing plate manufactured using the laminated film, the slow axis direction of the liquid crystal alignment solidified layer and the absorption axis direction of the polarizer can cross at a desired angle.

[0014] Hereinafter, each member constituting the laminated film will be described.

[0015] B. Stretched film The stretched film 1 is prepared by stretching a raw film having a long shape in the longitudinal direction or width direction, as described in detail below. The raw film has a resin film corresponding to the film substrate 11 and a thin resin film corresponding to the alignment layer 12.

[0016] B-1.Film substrate As shown in FIG. 1, the stretched film 1 includes a film substrate 11 and an alignment layer 12 . The film substrate 11 is made of any suitable resin material. Examples of the resin material include polyester-based resins such as polyethylene terephthalate (PET), cycloolefin (COP)-based resins such as polynorbornene, polycarbonate (PC)-based resins, (meth)acrylic resins, polyvinyl alcohol-based resins, polyamide-based resins, polyimide-based resins, polyethersulfone-based resins, polysulfone-based resins, polystyrene-based resins, polyolefin-based resins, and acetate-based resins. The resin materials may be used alone or in combination. Of the resin materials, polyester resins are preferable, and PET is more preferable. The film substrate 11 may have a single-layer structure or a laminated structure.

[0017] The film substrate 11 typically has an in-plane retardation in the stretching direction X. That is, the slow axis direction of the film substrate 11 and the slow axis direction of the liquid crystal alignment solidified layer typically intersect with each other. In one embodiment, the in-plane retardation Re(550) of the film substrate 11 is larger than the in-plane retardation Re(550) of the liquid crystal alignment fixed layer 2. The in-plane retardation Re(550) of the film substrate 11 is, for example, 10 nm to 200 nm, and preferably 30 nm to 100 nm.

[0018] The thickness of the film substrate 11 is, for example, 10 μm to 100 μm, for example, 20 μm to 70 μm, or for example, 25 μm to 35 μm.

[0019] B-2.Alignment film The alignment film 12 is laminated on the surface of the film substrate 11. The stretched film typically has an alignment regulating force that homogeneously aligns the liquid crystal compound in a direction intersecting the stretching direction of the stretched film 1 (the slow axis direction of the film substrate 11).

[0020] The alignment film 12 contains a cellulose-based resin having a constitutional unit represented by the above general formula (1). R in the above general formula (1) 1 ~R 6 Among these, the number of atomic groups represented by the above general formula (3) is 1 to 6, and preferably 1 to 3. In addition, R in the above general formula (1) 1 ~R 6 Among these, the number of methylcarbonyl groups represented by the above general formula (2) is 0 to 5, for example, 1 to 4, and for example, 3 or 4. In addition, R in the above general formula (1) 1 ~R 6 Among these, the number of hydrogen atoms is 0 to 5, for example 1 or 2, and also for example 0 or 1. When the cellulose-based resin has such a structure, the angle between the stretching direction of the stretched film and the slow axis direction of the liquid crystal alignment solidified layer can be stably adjusted within the above range.

[0021] In the above general formula (3), R 7 The number of carbon atoms of the hydrocarbon group represented by the formula: is, for example, 2 to 6, and preferably 2 to 4. Examples of such a hydrocarbon group include an alkyl group, an alkenyl group, an alkynyl group, and an aryl group, and preferably an alkyl group, and more preferably an ethyl group or a propyl group. In the above general formula (3), R 7 is an alkyl group, the angle between the stretching direction of the stretched film and the slow axis direction of the liquid crystal alignment solidified layer can be adjusted more stably within the above range. In the above general formula (3), R 7 The hydrogen atom of the hydrocarbon group represented by the following formula may be substituted with a halogen atom (typically, fluorine).

[0022] R in the above general formula (1) 1 ~R 6 When more than one of the R 7 may be different from each other or may be the same as each other. 7 are preferably identical to each other.

[0023] The cellulose-based resin may contain other structural units in addition to the structural unit represented by the general formula (1) above, as long as the effect of the present invention is not impaired. 1 ~R 6 In one embodiment, all of the structural units are methylcarbonyl groups (general formula (2) above).

[0024] In the cellulose-based resin, the content of the structural unit represented by the general formula (1) is, for example, more than 50 mass%, preferably 80 mass% or more, more preferably 90 mass% or more. In the cellulose-based resin, the upper limit of the content of the structural unit represented by the general formula (1) is 100 mass%.

[0025] The weight average molecular weight Mw of the cellulose-based resin is, for example, 70,000 to 150,000, and preferably 90,000 to 130,000.

[0026] In one embodiment, the alignment film 12 contains a sucrose derivative in addition to the above-mentioned cellulose-based resin. The molecular weight of the sucrose derivative is 1000 or less, preferably 800 or less, and more preferably 500 or less. The lower limit of the molecular weight of the sucrose derivative is typically 400. When the alignment film contains a sucrose derivative, the angle between the stretching direction of the stretched film and the slow axis direction of the liquid crystal alignment solidified layer can be stably adjusted within the above range. This phenomenon is presumably caused by the atomic group represented by the above general formula (3) interacting with the sucrose derivative and being oriented with a greater deviation from the cellulose main skeleton.

[0027] Examples of sucrose derivatives include sucrose esters such as sucrose benzoate, sucrose acetate, etc. The sucrose derivatives may be used alone or in combination. Of the sucrose derivatives, preferred are sucrose benzoate and sucrose acetate.

[0028] The content of the sucrose derivative is, for example, 0 parts by mass or more, preferably 1 part by mass or more, more preferably 3 parts by mass or more, even more preferably 5 parts by mass or more, and particularly preferably 6 parts by mass or more, relative to 100 parts by mass of the cellulose-based resin. On the other hand, the content of the sucrose derivative is, for example, 20 parts by mass or less, preferably 15 parts by mass or less, more preferably 13 parts by mass or less, even more preferably 10 parts by mass or less, and particularly preferably 9 parts by mass or less, relative to 100 parts by mass of the cellulose-based resin. When the content of the sucrose derivative is within such a range, the angle between the stretching direction of the stretched film and the slow axis direction of the liquid crystal alignment solidified layer can be adjusted more stably within the above range.

[0029] The thickness of the alignment film 12 is preferably 9 μm or less, more preferably 8 μm or less, and even more preferably 6 μm or less. On the other hand, the thickness of the alignment film 12 is preferably 0.2 μm or more, and more preferably 0.5 μm or more. If the thickness of the alignment film is in such a range, the occurrence of lattice unevenness in the liquid crystal alignment solidified layer can be stably suppressed, and as a result, an excellent appearance can be stably imparted to the liquid crystal alignment solidified layer.

[0030] The alignment film 12 typically has an in-plane retardation in the stretching direction X. That is, the slow axis direction of the alignment film 12 and the slow axis direction of the liquid crystal alignment solidified layer typically intersect with each other. The in-plane retardation Re(550) of the alignment film 12 is, for example, 0.1 nm to 20 nm, and preferably 0.5 nm to 10 nm.

[0031] C. Liquid crystal alignment solidification layer The liquid crystal alignment solidified layer 2 is located on the opposite side of the alignment film 12 to the film substrate 11, and is provided on the surface of the alignment film 12. In the liquid crystal alignment solidified layer 2, rod-shaped liquid crystal compounds are homogeneously aligned in a state aligned in a direction intersecting the stretching direction of the stretched film 1 (the slow axis direction of the film substrate 11). As described in detail below, the liquid crystal alignment solidified layer 2 is prepared by applying a liquid crystal coating liquid containing rod-shaped liquid crystal compounds onto the alignment film 12, followed by heating to align the liquid crystal compounds and fix the alignment state.

[0032] Examples of the liquid crystal compound include a liquid crystal compound having a nematic liquid crystal phase (nematic liquid crystal). Examples of such liquid crystal compounds include a liquid crystal polymer and a liquid crystal monomer. The liquid crystal compounds may be used alone or in combination. The mechanism by which the liquid crystal compound exhibits liquid crystallinity may be lyotropic or thermotropic, and is preferably thermotropic. When the mechanism by which the liquid crystal compound exhibits liquid crystallinity is thermotropic, the temperature at which the liquid crystal compound exhibits liquid crystallinity (liquid crystal phase transition temperature) is, for example, 40°C to 200°C, preferably 50°C to 150°C, and more preferably 55°C to 100°C.

[0033] Among the liquid crystal compounds, a liquid crystal monomer is preferably used, and a polymerizable liquid crystal monomer and / or a crosslinkable liquid crystal monomer is more preferably used. As a result, after the liquid crystal monomer is aligned, the alignment state of the liquid crystal monomer can be fixed, for example, by polymerizing or crosslinking the liquid crystal monomers with each other. Here, a polymer is formed by polymerization, and a three-dimensional network structure is formed by crosslinking, but these are non-liquid crystal. Therefore, the formed liquid crystal alignment solidified layer does not undergo transition to a liquid crystal phase, a glass phase, or a crystalline phase due to, for example, a temperature change specific to a liquid crystal compound. As a result, the formed liquid crystal alignment solidified layer becomes a retardation layer that is not affected by temperature changes and has extremely excellent stability.

[0034] In one embodiment, the liquid crystal monomer has a mesogenic group and a photopolymerizable functional group in one molecule. Examples of the mesogenic group include cyclic structures such as a biphenyl group, a phenylbenzoate group, a phenylcyclohexane group, an azoxybenzene group, an azomethine group, an azobenzene group, a phenylpyrimidine group, a diphenylacetylene group, a diphenylbenzoate group, a bicyclohexane group, a cyclohexylbenzene group, and a terphenyl group. The terminals of these cyclic units may have a substituent such as a cyano group, an alkyl group, an alkoxy group, or a halogen group.

[0035] Examples of the photopolymerizable functional group include a (meth)acryloyl group, an epoxy group, and a vinyl ether group, and preferably a (meth)acryloyl group. Note that the term "(meth)acryloyl" includes acryloyl and / or methacryloyl. The number of photopolymerizable functional groups contained in the liquid crystal monomer is preferably 2 or more.

[0036] An example of such a liquid crystal monomer is a compound represented by the following general formula (I).

[0037] [ka] (In the above general formula (I), R represents a hydrogen atom or a methyl group. A and D each independently represent a 1,4-phenylene group or a 1,4-cyclohexylene group. B represents a 1,4-phenylene group, a 1,4-cyclohexylene group, a 4,4'-biphenylene group or a 4,4'-bicyclohexylene group. Y and Z each independently represent -COO-, -OCO- or -O-. g and h each independently represent an integer of 2 to 6.)

[0038] An example of a commercially available liquid crystal monomer represented by the above general formula (I) is "Paliocolor LC242" manufactured by BASF. Specific examples of liquid crystal compounds and details of a method for forming a liquid crystal alignment solidified layer are described in, for example, JP-A-2006-163343 and JP-A-2006-178389, the disclosures of which are incorporated herein by reference.

[0039] Such a liquid crystal alignment solidified layer 2 has an in-plane retardation as described above. The refractive index of the liquid crystal alignment solidified layer 2 typically has the relationship nx>ny=nz. Here, "ny=nz" includes not only the case where ny and nz are completely identical, but also the case where ny and nz are substantially identical. The in-plane retardation Re(550) of the liquid crystal alignment solidified layer 2 is adjusted arbitrarily and appropriately. The in-plane retardation Re(550) of the liquid crystal alignment solidified layer 2 is, for example, 100 nm to 300 nm. The thickness of the liquid crystal alignment solidified layer 2 is, for example, 0.5 μm to 7 μm.

[0040] In one embodiment, the liquid crystal alignment solidified layer 2 is configured as a so-called λ / 2 plate. In this case, the in-plane retardation Re(550) of the liquid crystal alignment solidified layer 2 is preferably 200 nm to 300 nm, more preferably 220 nm to 290 nm, and further preferably 250 nm to 280 nm. The thickness of the liquid crystal alignment solidified layer 2 configured as a λ / 2 plate is preferably 1 μm to 7 μm, and more preferably 1.5 μm to 2.5 μm.

[0041] In another embodiment, the liquid crystal alignment solidified layer 2 is configured as a so-called λ / 4 plate. In this case, the in-plane retardation Re(550) of the liquid crystal alignment solidified layer 2 is preferably 100 nm to 190 nm, more preferably 110 nm to 170 nm, and further preferably 130 nm to 150 nm. The thickness of the liquid crystal alignment solidified layer 2 configured as a λ / 4 plate is preferably 0.5 μm to 2 μm, and more preferably 1.0 μm to 1.5 μm.

[0042] In the liquid crystal alignment fixed layer 2, Re(450) / Re(550) is, for example, 0.90 or more, preferably 1.05 or more, more preferably 1.08 or more, and further preferably 1.10 or more.

[0043] D. Method for manufacturing a polarizing plate with a retardation layer Next, a method for producing the retardation layer-attached polarizing plate 101 using the laminated film 100 will be described with reference to FIGS.

[0044] In one embodiment, a manufacturing method of a polarizing plate 101 with a retardation layer includes the steps of: preparing a first stretched film 1a having a first film substrate 11a and a first alignment film 12a; forming a first liquid crystal alignment solidified layer 2a on the surface of the first alignment film 12a; preparing a second stretched film 1b having a second film substrate 11b and a second alignment film 12b; forming a second liquid crystal alignment solidified layer 2b on the surface of the second alignment film 12b; bonding the first liquid crystal alignment solidified layer 2a and the second liquid crystal alignment solidified layer 2b together; peeling the first stretched film 1a from the first liquid crystal alignment solidified layer 2a; and bonding a polarizer 31 to the surface of the first liquid crystal alignment solidified layer 2a opposite the second liquid crystal alignment solidified layer 2b. Each of the first alignment film 12a and the second alignment film 12b contains a cellulose-based resin having a structural unit represented by the above general formula (1). Each of the first alignment film 12a and the second alignment film 12b has a thickness of 0.1 μm to 10 μm. According to this method, it is possible to smoothly manufacture a polarizing plate with a retardation layer, which includes a first liquid crystal alignment solidified layer and a second liquid crystal alignment solidified layer, and in which the slow axis directions of the layers are set in a predetermined direction relative to the absorption axis of the polarizer. Such a polarizing plate with a retardation layer can have excellent circular polarization characteristics in a wide band.

[0045] D-1. Preparation of the first stretched film As shown in Figs. 3 and 4, in the step of preparing the first stretched film, first, a raw film having a long shape is prepared. The original film has a laminated structure, and includes a resin film corresponding to the film substrate 11 and a thin resin film corresponding to the alignment film 12 . The resin film is the film substrate 11 before stretching. Therefore, except for the thickness, the resin film can be explained in the same manner as the above-mentioned film substrate 11. The thickness of the resin film is, for example, 10 μm to 200 μm, and preferably 30 μm to 100 μm. The resin thin film is the alignment film 12 before stretching. Therefore, except for the thickness and the presence or absence of an alignment regulating force, the resin thin film can be explained in the same manner as the above-mentioned alignment film 12. The thickness of the resin thin film is, for example, 0.2 μm to 7 μm, and preferably 1 μm to 3 μm. The thin resin film is formed, for example, by applying a resin solution in which a material is dissolved to one surface in the thickness direction of a long resin film, and then heating and drying the applied resin solution as necessary.

[0046] Next, the long resin film is longitudinally stretched while being transported in the long direction to prepare a first stretched film 1a in which the long direction (MD) is substantially parallel to the stretching direction X1. The first stretched film 1a has a long shape and includes a first film substrate 11a formed by stretching a resin film and a first alignment film 12a formed by stretching a resin thin film. The first film substrate 11a typically has a slow axis substantially parallel to the stretching direction X1. The stretching temperature is, for example, 160° C. to 200° C., and preferably 170° C. to 180° C. The stretching ratio is, for example, 1.05 times to 1.50 times, and preferably 1.10 times to 1.30 times.

[0047] D-2. Step of forming first liquid crystal alignment solidified layer Next, the liquid crystal coating liquid containing the above-mentioned liquid crystal compound is applied onto the first alignment layer 12a of the first stretched film 1a by any appropriate method (typically, with a bar coater).

[0048] The liquid crystal coating liquid is typically prepared by adding the above-mentioned liquid crystal compound to any appropriate solvent and mixing them. Examples of the solvent include halogenated hydrocarbons such as chloroform, dichloromethane, carbon tetrachloride, dichloroethane, tetrachloroethane, trichloroethylene, tetrachloroethylene, chlorobenzene, and orthodichlorobenzene; phenols such as phenol and parachlorophenol; aromatic hydrocarbons such as benzene, toluene, xylene, methoxybenzene, and 1,2-dimethoxybenzene; ketone-based solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, cyclopentanone, 2-pyrrolidone, and N-methyl-2-pyrrolidone; ester-based solvents such as ethyl acetate and butyl acetate; alcohol-based solvents such as t-butyl alcohol, glycerin, ethylene glycol, triethylene glycol, ethylene glycol monomethyl ether, diethylene glycol dimethyl ether, propylene glycol, dipropylene glycol, and 2-methyl-2,4-pentanediol; amide-based solvents such as dimethylformamide and dimethylacetamide; nitrile-based solvents such as acetonitrile and butyronitrile; ether-based solvents such as diethyl ether, dibutyl ether, and tetrahydrofuran; and ethyl cellosolve and butyl cellosolve. The solvents may be used alone or in combination. Of the solvents, preferred are toluene and butyl acetate.

[0049] When the liquid crystal compound is a liquid crystal monomer having a photopolymerizable functional group, the liquid crystal coating liquid preferably further contains a photopolymerization initiator (photoradical generator). The photopolymerization initiator is arbitrarily and appropriately selected according to the type of liquid crystal monomer (type of photopolymerizable functional group). Examples of the photopolymerization initiator include a photocation generator and a photoanion generator. The content of the photopolymerization initiator is, for example, 0.01 parts by mass to 10 parts by mass with respect to 100 parts by mass of the liquid crystal monomer.

[0050] The liquid crystal coating liquid may further contain any appropriate additives as necessary, such as a sensitizer, a surfactant, and a leveling agent. The solid content concentration in the liquid crystal coating liquid is, for example, 5% by mass to 60% by mass.

[0051] Next, the coating film of the liquid crystal coating fluid formed on the first alignment film 12a is heated, and then irradiated with ultraviolet light as necessary. The heating temperature is, for example, 40° C. to 200° C., and preferably 60° C. to 140° C. The heating time is, for example, 30 seconds to 300 seconds, and preferably 60 seconds to 120 seconds.

[0052] As a result, the liquid crystal compound is solidified (cured) in an aligned state, and a first liquid crystal alignment solidified layer 2a is formed on the first alignment film 12a. The first liquid crystal alignment solidified layer 2a is typically configured as a λ / 2 plate. In this manner, a first laminated film 100a is prepared, which includes a first stretched film 1a and a first liquid crystal alignment solidified layer 2a (typically a λ / 2 plate). In the first laminate film 100a, the slow axis direction Y1 of the first liquid crystal alignment solidified layer 2a is inclined within the above-mentioned angle range with respect to the stretching direction X of the first stretched film 1a. When the width direction (TD direction) of the first stretched film 1a is set to 0°, the angle between the slow axis direction Y1 of the first liquid crystal alignment solidified layer 2a and the width direction (TD direction) of the first stretched film 1a exceeds 91°, for example, preferably exceeds 95°, and more preferably exceeds 100°. On the other hand, the angle between the slow axis direction Y1 of the first liquid crystal alignment solidified layer 2a and the width direction (TD direction) of the first stretched film 1a is, for example, 120° or less, preferably 110° or less.

[0053] D-3. Preparation of second stretched film In the second stretched film preparation process, similar to the first stretched film preparation process, the above-mentioned raw film is prepared, and the raw film is stretched laterally while being transported in the longitudinal direction to prepare a second stretched film 1b in which the longitudinal direction (MD direction) and the stretching direction X2 are substantially perpendicular to each other. The width dimension of the raw film can be arbitrarily and appropriately adjusted so that the width dimension of the second stretched film 1b coincides with the width dimension of the first stretched film 1a. This results in a long second stretched film 1b including the second film substrate 11b and the second alignment layer 12b. The second film substrate 11b typically has a slow axis substantially parallel to the stretching direction X2. The stretching temperature is, for example, 160° C. to 200° C., and preferably 170° C. to 180° C. The stretching ratio is, for example, 1.05 times to 1.50 times, and preferably 1.10 times to 1.30 times.

[0054] D-4. Step of forming second liquid crystal alignment solidification layer Next, similar to the process of forming the first liquid crystal alignment solidified layer, the above-mentioned liquid crystal coating liquid is applied onto the second alignment film 12b of the second stretched film 1b, and then the coating film of the liquid crystal coating liquid formed on the second alignment film 12b is heated and, if necessary, irradiated with ultraviolet light.

[0055] As a result, the liquid crystal compound is solidified (cured) in an aligned state, and a second liquid crystal alignment solidified layer 2b is formed on the second alignment film 12b. The second liquid crystal alignment solidified layer 2b is typically configured as a λ / 4 plate. In this manner, a second laminated film 100b is prepared, which includes a second stretched film 1b and a second liquid crystal alignment solidified layer 2b (typically a λ / 4 plate). In the second laminate film 100b, the slow axis direction Y2 of the second liquid crystal alignment solidified layer 2b is inclined within the above-mentioned angle range with respect to the stretching direction X2 of the second stretched film 1b. When the width direction (TD direction) of the second stretched film 1b is set to 0°, the angle between the slow axis direction Y2 of the second liquid crystal alignment solidified layer 2b and the width direction (TD direction) of the second stretched film 1b exceeds 1°, for example, preferably exceeds 5°, and more preferably exceeds 10°. On the other hand, the angle between the slow axis direction Y2 of the second liquid crystal alignment solidified layer 2b and the width direction (TD direction) of the second stretched film 1b is, for example, 30° or less, preferably 20° or less.

[0056] D-5. Step of bonding the first liquid crystal alignment solidified layer and the second liquid crystal alignment solidified layer Next, as shown in Figures 5 and 6, the first liquid crystal alignment solidified layer 2a of the first laminate film 100a and the second liquid crystal alignment solidified layer 2b of the second laminate film 100b are bonded together via any suitable adhesive layer (not shown). In one embodiment, the first liquid crystal alignment solidified layer 2a and the second liquid crystal alignment solidified layer 2b are bonded together by a roll-to-roll method with their longitudinal directions aligned. This can improve the manufacturing efficiency of the retardation layer-attached polarizing plate including the first liquid crystal alignment solidified layer and the second liquid crystal alignment solidified layer.

[0057] The adhesive layer may be a pressure sensitive adhesive layer or an adhesive layer. The adhesive layer is preferably an adhesive layer. The adhesive constituting the adhesive layer may be, for example, a thermosetting adhesive or an ultraviolet curing adhesive, and preferably an ultraviolet curing adhesive. The thickness of the adhesive layer is, for example, 0.4 μm to 3.0 μm.

[0058] In this way, a layered phase difference film 21 in which the first liquid crystal alignment solidified layer 2a and the second liquid crystal alignment solidified layer 2b are laminated is prepared.

[0059] D-6. Peeling off the first stretched film Next, the first stretched film 1a is peeled off from the first liquid crystal alignment solidified layer 2a. Typically, the first alignment film 12a and the first film substrate 11a are peeled off together. This exposes the surface of the first liquid crystal alignment solidified layer 2a opposite to the second liquid crystal alignment solidified layer 2b.

[0060] D-7. Polarizer attachment process 7, a long-sized polarizer 31 is attached to the surface of the first liquid crystal alignment solidified layer 2a opposite to the second liquid crystal alignment solidified layer 2b via the above-mentioned adhesive layer (not shown). Typically, a polarizing plate 3 including the polarizer 31 is attached to the first liquid crystal alignment solidified layer 2a of the laminated phase difference film 21.

[0061] D-7-1. Polarizing plate The polarizing plate 3 includes at least a polarizer 31 and has an elongated shape extending in a predetermined direction. The absorption axis direction of the polarizer 31 (the direction in which the absorption axis extends) is typically substantially parallel to the elongated direction of the polarizing plate 3.

[0062] Any appropriate polarizer can be adopted as the polarizer 31. For example, the resin film forming the polarizer may be a single-layer resin film or a laminate of two or more layers.

[0063] Specific examples of polarizers made of a single-layer resin film include hydrophilic polymer films such as polyvinyl alcohol (PVA) films, partially formalized PVA films, and partially saponified ethylene-vinyl acetate copolymer films that have been dyed with iodine or a dichroic substance such as a dichroic dye and stretched, and polyene-based oriented films such as dehydrated PVA films and dehydrochlorinated polyvinyl chloride films. A polarizer obtained by dyeing a long PVA film with iodine and uniaxially stretching it is preferably used because of its excellent optical properties.

[0064] The dyeing with iodine is carried out, for example, by immersing the PVA-based film in an aqueous iodine solution. The stretching ratio of the uniaxial stretching is preferably 3 times or more and 7 times or less. The stretching may be carried out after the dyeing treatment or while the dyeing treatment is being carried out. Alternatively, the dyeing may be carried out after the stretching. The stretching direction is typically substantially parallel to the longitudinal direction of the PVA-based film. If necessary, the PVA-based film is subjected to a swelling treatment, a crosslinking treatment, a washing treatment, a drying treatment, etc. For example, by immersing the PVA-based film in water and washing it before dyeing, it is possible not only to wash off dirt and antiblocking agents on the surface of the PVA-based film but also to swell the PVA-based film and prevent uneven dyeing, etc.

[0065] Specific examples of polarizers obtained using a laminate include a laminate of a resin substrate and a PVA-based resin layer (PVA-based resin film) laminated on the resin substrate, or a polarizer obtained using a laminate of a resin substrate and a PVA-based resin layer formed by coating on the resin substrate. A polarizer obtained using a laminate of a resin substrate and a PVA-based resin layer formed by coating on the resin substrate can be produced by, for example, applying a PVA-based resin solution to a long-sized resin substrate, drying the substrate to form a PVA-based resin layer on the resin substrate, and obtaining a laminate of the resin substrate and the PVA-based resin layer; and stretching and dyeing the laminate to make the PVA-based resin layer into a polarizer. In one embodiment of the present invention, a polyvinyl alcohol-based resin layer containing a halide and a polyvinyl alcohol-based resin is preferably formed on one side of a long-sized resin substrate. The stretching typically includes immersing the laminate in an aqueous solution of boric acid to stretch it. Furthermore, the stretching may further include, as necessary, stretching the laminate in air at a high temperature (for example, 95° C. or higher) before stretching in the aqueous solution of boric acid. The stretching direction is typically substantially parallel to the longitudinal direction of the laminate. In addition, in one embodiment of the present invention, the laminate is preferably subjected to a drying shrinkage treatment in which the laminate is heated while being transported in the longitudinal direction to shrink the laminate by 2% or more in the width direction. Typically, the manufacturing method of this embodiment includes subjecting the laminate to an air-assisted stretching treatment, a dyeing treatment, an underwater stretching treatment, and a drying shrinkage treatment in this order. By introducing the auxiliary stretching, even when PVA is applied onto a thermoplastic resin, it is possible to increase the crystallinity of the PVA, and to achieve high optical properties. In addition, by simultaneously increasing the orientation of the PVA in advance, problems such as a decrease in the orientation of the PVA or dissolution when immersed in water in the subsequent dyeing step or stretching step can be prevented, and high optical properties can be achieved. Furthermore, when the PVA-based resin layer is immersed in a liquid, the orientation disorder and the decrease in the orientation of the polyvinyl alcohol molecules can be suppressed compared to when the PVA-based resin layer does not contain a halide. This can improve the optical properties of a polarizer obtained through a treatment step in which the laminate is immersed in a liquid, such as a dyeing treatment and an underwater stretching treatment. Furthermore, the optical properties can be improved by shrinking the laminate in the width direction by the drying shrinkage treatment. The obtained laminate of resin substrate / polarizer may be used as it is (i.e., the resin substrate may be used as a protective layer for the polarizer), or the resin substrate may be peeled off from the laminate of resin substrate / polarizer, and any suitable protective layer may be laminated on the peeled surface depending on the purpose. Details of the method for producing such a polarizer are described in, for example, JP2012-73580A and JP6470455A. The entire disclosures of these publications are incorporated herein by reference.

[0066] The thickness of the polarizer is, for example, 1 μm to 80 μm, preferably 1 μm to 15 μm, more preferably 1 μm to 12 μm, further preferably 3 μm to 12 μm, and particularly preferably 3 μm to 8 μm. When the thickness of the polarizer is within this range, curling during heating can be well suppressed, and good appearance durability during heating can be obtained.

[0067] The polarizer preferably exhibits absorption dichroism at any wavelength of 380 nm to 780 nm. The single transmittance of the polarizer is, for example, 41.5% or more and 46.0% or less, preferably 43.0% or more and 46.0% or less, more preferably 44.5% or more and 46.0% or less. The polarization degree of the polarizer is preferably 97.0% or more, more preferably 99.0% or more, and even more preferably 99.9% or more.

[0068] The polarizing plate 3 may further include a protective layer. The protective layer is provided on at least one surface of the polarizer. In the illustrated example, the polarizing plate 3 includes a protective layer 32 provided on the surface of the polarizer 31 opposite to the first liquid crystal alignment solidified layer 2a.

[0069] The protective layer is formed of any suitable film that can be used as a protective layer for a polarizer. Specific examples of materials that are the main components of the film include cellulose-based resins such as triacetyl cellulose (TAC), and transparent resins such as polyesters, polyvinyl alcohols, polycarbonates, polyamides, polyimides, polyethersulfones, polysulfones, polystyrenes, polynorbornenes, polyolefins, (meth)acrylics, and acetates. Other examples include thermosetting resins or ultraviolet-curing resins such as (meth)acrylics, urethanes, (meth)acrylic urethanes, epoxys, and silicones. Other examples include glassy polymers such as siloxane polymers. Polymer films described in JP 2001-343529 A (WO01 / 37007) can also be used.

[0070] If necessary, the protective layer may be subjected to a surface treatment such as a hard coat treatment, an anti-reflection treatment, an anti-sticking treatment, or an anti-glare treatment.

[0071] The thickness of the protective layer is typically 5 mm or less, preferably 1 mm or less, more preferably 1 μm to 500 μm, and even more preferably 5 μm to 150 μm. In addition, when a surface treatment is applied, the thickness of the protective layer includes the thickness of the surface treatment layer.

[0072] In one embodiment, such a polarizing plate 3 and the first liquid crystal alignment solidified layer 2a of the laminated phase difference film 21 are bonded together by a roll-to-roll method with their longitudinal directions aligned. This can further improve the production efficiency of the phase difference layer-attached polarizing plate including the first liquid crystal alignment solidified layer and the second liquid crystal alignment solidified layer.

[0073] Thereafter, if necessary, the second stretched film 1b (the second film substrate 11b and the second film substrate 11b) is peeled off from the second liquid crystal alignment solidified layer 2b. In this manner, the retardation layer-attached polarizing plate 101 is prepared.

[0074] As shown in FIG. 8, in the retardation layer-attached polarizing plate 101, the angle between the slow axis direction Y1 of the first liquid crystal alignment solidified layer 2a, which is typically configured as a λ / 2 plate, and the absorption axis direction Z of the polarizer 31 is, for example, 10° to 20°, preferably 13° to 17°, and more preferably approximately 15°. In addition, in the retardation layer-attached polarizing plate 101, the angle between the slow axis direction Y2 of the second liquid crystal alignment solidified layer 2b, which is typically configured as a λ / 4 plate, and the absorption axis direction Z of the polarizer 31 is, for example, 65° to 85°, preferably 72° to 78°, and more preferably approximately 75°.

[0075] E. Image display device The retardation layer-attached polarizing plate 101 described in the above section D can be applied to an image display device. Representative examples of the image display device include a liquid crystal display device and an organic EL display device. An image display device according to one embodiment includes an image display cell and the retardation layer-attached polarizing plate described in the above section D. Note that the image display device may be referred to as an optical display device, the image display panel may be referred to as an optical display panel, and the image display cell may be referred to as an optical display cell. EXAMPLES

[0076] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. The methods for measuring the various properties are as follows.

[0077] (1) Measurement of phase difference and slow axis direction The liquid crystal alignment layer of the laminated film obtained in the examples and comparative examples was attached to a glass plate via an adhesive layer, and then the stretched film was peeled off from the liquid crystal alignment layer. The retardation value of the liquid crystal alignment layer was then measured using a polarized retardation measurement system (manufactured by Axometrics, product name "AxoScan") at 23°C using light with a wavelength of 550 nm. From the measurement results, the slow axis direction of the liquid crystal alignment layer was determined. Next, the angle between the TD direction perpendicular to the machine direction (MD direction) of the laminated film and the slow axis direction of the liquid crystal alignment solidified layer was calculated. Also, the angle between the stretching direction of the stretched film and the slow axis direction of the liquid crystal alignment solidified layer was calculated. The results are shown in Table 1.

[0078] (2) Appearance evaluation The appearance of the liquid crystal alignment solidified layer of the laminated film obtained in the examples and comparative examples was visually observed under a backlight environment after laminating a polarizing plate, a laminated film, and a polarizing plate in that order, and evaluated according to the following criteria. The absorption axes of the two polarizing plates were set to be perpendicular to each other. The results are shown in Table 1. ◯: Lattice irregularities are not visible. ×: Lattice irregularities are visible.

[0079] [Example 1] <Preparation of Stretched Film> A polyethylene terephthalate (PET) film having a thickness of 50 μm was prepared. The PET film had a long shape extending in a predetermined direction. Cellulose acetyl propionate (main polymer) was dissolved in butyl acetate to prepare a cellulose-based resin solution. Next, the cellulose resin solution was applied onto the PET film to form a coating film. The coating film was then dried at 80° C. for 300 hours. The thickness of the dried coating film (thin resin film) was 1 μm. In this way, a raw film having a PET film and a thin resin film containing cellulose acetyl propionate was prepared. The raw film had a long shape. Next, the raw film was longitudinally stretched 1.15 times at a stretching temperature of 170° C. while being transported in the longitudinal direction to prepare a stretched film in which the longitudinal direction (MD) and the stretching direction were substantially parallel. That is, in Example 1, the width direction (TD) of the stretched film and the stretching direction were substantially perpendicular to each other, and the angle between them was 90°. The stretched film had a film substrate in which a PET film was stretched and an orientation film in which a dried coating film was stretched. The slow axis direction in the orientation film was substantially parallel to the stretching direction (longitudinal direction). The thickness of the orientation film is shown in Table 1. <Preparation of liquid crystal coating solution> A liquid crystal coating solution was prepared by dissolving 100 parts by mass of a polymerizable liquid crystal compound exhibiting a nematic liquid crystal phase (manufactured by BASF, product name Paliocolor LC242), 5 parts by mass of a photopolymerization initiator (manufactured by Ciba Specialty Chemicals, product name Irgacure 907), and 0.1 parts by mass of a leveling agent (manufactured by DIC, product name BYK-361N) in 400 parts by mass of butyl acetate (organic solvent). <Formation of liquid crystal alignment solidified layer> Next, while the stretched film was being transported in the longitudinal direction, a liquid crystal coating solution was applied onto the alignment film of the stretched film using a bar coater, and the film was dried by heating at 100°C for 60 seconds. As a result, the polymerizable liquid crystal compound was aligned. After that, the liquid crystal layer containing the aligned polymerizable liquid crystal compound was irradiated with ultraviolet light to harden the liquid crystal layer. As a result, a liquid crystal alignment solidified layer having a thickness of 1 μm was formed on the alignment film of the stretched film. In this manner, a laminated film including a stretched film and a liquid crystal alignment solidified layer was produced.

[0080] [Example 2] A laminated film was produced in the same manner as in Example 1, except that sucrose benzoate (a sucrose derivative) was added to the cellulose resin solution in the proportions shown in Table 1 and the thickness of the alignment film was changed to 1.0 μm.

[0081] [Example 3] A laminated film was produced in the same manner as in Example 1, except that the thickness of the alignment film was changed to 5.0 μm.

[0082] [Example 4] A laminated film was produced in the same manner as in Example 1, except that the thickness of the orientation film was changed to 8.0 μm, and the raw film was transversely stretched 1.10 times at a stretching temperature of 175° C. while being transported in the longitudinal direction to prepare a stretched film in which the longitudinal direction and the stretching direction were substantially perpendicular to each other. That is, in Example 4, the TD direction and the stretching direction in the stretched film were substantially parallel, and the angle between them was 0°.

[0083] [Comparative Example 1] A laminated film was produced in the same manner as in Example 1, except that the thickness of the alignment film was changed to 11.0 μm.

[0084] [Comparative Example 2] A laminated film was produced in the same manner as in Example 1, except that the stretched film having the film substrate and the orientation film was changed to a stretched film having the following single-layer structure. The stretched film having a single layer structure was prepared by longitudinally stretching a resin film containing cellulose acetyl propionate at a stretching temperature of 170°C to 1.15 times the original length while conveying the resin film in the longitudinal direction. That is, the stretched film is composed of cellulose acetyl propionate and can function as an orientation film. The thickness of the stretched film (orientation film) was 35 μm.

[0085] [Table 1]

[0086] [evaluation] As is clear from Table 1, when the orientation film of the stretched film contains a cellulose resin having a constitutional unit represented by the above general formula (1), the liquid crystal coating liquid is applied to the orientation film to form a liquid crystal orientation solidified layer, and the slow axis direction of the liquid crystal orientation solidified layer and the stretching direction of the stretched film can be crossed with each other. Therefore, when a long liquid crystal orientation solidified layer and a long polarizer are prepared and attached by a roll-to-roll method, the slow axis direction of the liquid crystal orientation solidified layer and the absorption axis direction of the polarizer can be crossed without being substantially perpendicular to each other. That is, it is possible to manufacture a retardation layer-attached polarizing plate in which the slow axis direction of the liquid crystal orientation solidified layer and the absorption axis direction of the polarizer form a desired angle by the roll-to-roll method, and it is possible to improve the manufacturing efficiency of the retardation layer-attached polarizing plate. Furthermore, it is understood that when the thickness of the alignment film is 10 μm or less, the occurrence of lattice irregularities in the liquid crystal alignment layer to be manufactured can be suppressed, and the appearance of the liquid crystal alignment layer can be improved. [Industrial Applicability]

[0087] The laminate film according to the embodiment of the present invention can be suitably applied to image display devices (typically, liquid crystal display devices and organic EL display devices). [Explanation of symbols]

[0088] 1. Stretched film 11 Film substrate 12 Alignment film 2 Liquid crystal alignment layer 3. Polarizing Plate 31 Polarizer 100 Laminated Film 101 Polarizing plate with retardation layer

Claims

1. A stretched film stretched in a predetermined direction, the stretched film including a film substrate and an orientation film; a liquid crystal alignment solidified layer laminated on a surface of the alignment film, the liquid crystal alignment solidified layer including a rod-shaped liquid crystal compound that is homogeneously aligned; The alignment film contains a cellulose-based resin having a constitutional unit represented by the following general formula (1): The thickness of the alignment film is 0.1 μm to 10 μm. A laminate film, in which the slow axis direction of the liquid crystal alignment solidified layer and the stretching direction of the stretched film intersect with each other: 【Chemistry 1】 (In the above general formula (1), R １ ~R ６ each independently represents a hydrogen atom, a methylcarbonyl group represented by the following general formula (2), or an atomic group represented by the following general formula (3); R １ ~R ６ At least one of the above represents an atomic group represented by the following general formula (3): 【Chemistry 2】 【Chemistry 3】 (In the above general formula (3), R ７ represents a hydrocarbon group having 2 or more carbon atoms.

2. In the above general formula (3), R ７ The laminate film according to claim 1 , wherein represents an alkyl group having 2 or more carbon atoms.

3. In the above general formula (3), R ７ The laminate film according to claim 1 , wherein represents an ethyl group or a propyl group.

4. In the above general formula (1), R １ ~R ６ The laminate film according to claim 1 , wherein one or more and three or less of the above represent an atomic group represented by the general formula (3).

5. 2. The laminated film according to claim 1, wherein an angle between the stretching direction of the stretched film and the slow axis direction of the liquid crystal alignment solidified layer is more than 5 degrees and is not more than 20 degrees.

6. The laminated film according to claim 1 , wherein the alignment film further contains a sucrose derivative having a molecular weight of 1000 or less.

7. A step of preparing a first stretched film having a long shape, the first stretched film including a first film substrate and a first orientation film; forming a first liquid crystal alignment solidified layer containing homogeneously aligned rod-shaped liquid crystal compounds on a surface of the first alignment film; A step of preparing a second stretched film having a long shape, the second stretched film including a second film substrate and a second orientation film; forming a second liquid crystal alignment solidified layer containing homogeneously aligned rod-shaped liquid crystal compounds on a surface of the second alignment film; a step of bonding the first liquid crystal alignment solidified layer and the second liquid crystal alignment solidified layer; peeling the first stretched film from the first liquid crystal alignment solidified layer attached to the second liquid crystal alignment solidified layer; and attaching a polarizer having a long shape to a surface of the first liquid crystal alignment solidified layer opposite to the second liquid crystal alignment solidified layer, Each of the first alignment film and the second alignment film contains a cellulose-based resin having a constitutional unit represented by the following general formula (1), The thickness of each of the first alignment film and the second alignment film is 0.1 μm to 10 μm; The stretching direction of the first stretched film is substantially parallel to the longitudinal direction of the first stretched film, The stretching direction of the second stretched film is substantially perpendicular to the longitudinal direction of the second stretched film, a slow axis direction of the first liquid crystal alignment solidified layer and a stretching direction of the first stretched film intersect with each other, A method for producing a polarizing plate with a retardation layer, wherein the slow axis direction of the second liquid crystal alignment solidified layer and the stretching direction of the second stretched film are intersecting with each other: 【Chemistry 1】 (In the above general formula (1), R １ ~R ６ each independently represents a hydrogen atom, a methylcarbonyl group represented by the following general formula (2), or an atomic group represented by the following general formula (3); R １ ~R ６ At least one of the above represents an atomic group represented by the following general formula (3): 【Chemistry 2】 【Chemistry 3】 (In the above general formula (3), R ７ represents a hydrocarbon group having 2 or more carbon atoms.

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