JP2014182311A - Polarizing plate and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polarizing plate with a small film thickness.SOLUTION: The polarizing plate comprises an optical film comprising an optical anisotropic layer and an optically isotropic acryl polymer layer, and a polarizer. In the polarizing plate, the optical anisotropic layer is formed by irradiating a polymerizable composition containing a liquid crystal compound with light so as to polymerize the liquid crystal compound; the acryl polymer layer is formed by curing a polymerizable composition containing (meth)acrylate directly applied to the surface of the layer formed of the polymerizable composition containing the liquid crystal compound; and the film thickness of the acryl polymer layer is larger than the film thickness of the optical anisotropic layer.

Description

  The present invention relates to a polarizing plate and a method for producing the same.

  As the market for smartphones and tablet PCs expands, displays are increasingly required to be thinner. In this trend, in addition to the cellulose acylate polymer film conventionally used as a transparent and low birefringence optical film, various films such as an acrylic polymer film and a cycloolefin polymer film are polarizing plates. Attempts have been made to use it as a protective film (for example, Patent Document 1). These films are problematic in that they are expensive and tend to cause dents during handling, and there is room for improvement for practical use. Moreover, the structure in which a protective film has phase difference is also calculated | required for thickness reduction of a display.

JP 2009-175222 A

  An object of the present invention is to provide a polarizing plate having a thin film thickness. An object of the present invention is to provide a polarizing plate having a thin film optical film having a retardation as a protective film. Another object of the present invention is to provide a method for producing the polarizing plate.

A thin film may be manufactured and transported as a material to which a laminate film is attached for the purpose of preventing the above-described dents and scratches or handling. The present inventors have used a film that can function as a laminate film for forming a thin film as a temporary support, an acrylic polymer obtained by polymerizing the compound after coating a composition containing a polymerizable compound on the temporary support. An attempt was made to make a film. However, the problem of insufficient peelability between the temporary support and the acrylic polymer film was encountered. As a result of further diligent research by the present inventors to solve this problem, by providing an optically anisotropic layer formed from a liquid crystal compound before the formation of the acrylic polymer layer on the temporary support, It has been found that the peelability of the acrylic polymer layer from the temporary support is improved and a controlled retardation can be imparted. And the present inventors formed the thin film (optical anisotropy layer) which has the phase difference which this formed by photocuring of the composition containing a liquid crystal compound directly on a temporary support body without passing an alignment film. In this case, the present inventors have found that the thin film can be peeled off from the temporary support without any defects. Conventionally, even if the present inventors have made trial and error, a thin film (optically anisotropic layer) having a phase difference formed by photocuring a composition containing a liquid crystal compound cannot be peeled off from a temporary support without defects. The present inventors have suffered from a difficult problem that a thin film having a phase difference is easily broken when peeled off from a temporary support.
Based on the above findings, the present inventors have obtained an optical film material that can provide an optical film that can be used as a protective film for a polarizing plate, and have further studied and completed the present invention. That is, the present invention provides the following [1] to [11].

[1] An optical film including an optically anisotropic layer and an optically isotropic acrylic polymer layer, and a polarizing plate including a polarizer,
The optically anisotropic layer is a layer formed by light-irradiating a polymerizable composition containing a liquid crystal compound to polymerize the liquid crystal compound,
The acrylic polymer layer is a layer formed by curing a polymerizable composition containing (meth) acrylate applied directly to the surface of the layer formed from the polymerizable composition containing the liquid crystal compound,
The polarizing plate in which the film thickness of the acrylic polymer layer is larger than the film thickness of the optically anisotropic layer.
[2] The polarizing plate according to [1], wherein the optically anisotropic layer has a thickness of 0.5 μm to 5 μm.
[3] The polarizing plate according to [1], wherein the optically anisotropic layer has a thickness of 0.5 μm to 3 μm.

[4] The polarizing plate according to any one of [1] to [3], wherein the optically anisotropic layer and the polarizer are in direct contact.
[5] The polarizing plate according to any one of [1] to [4], wherein the acrylic polymer layer and the polarizer are in direct contact.
[6] including a cellulose acylate film,
The polarizing plate according to any one of [1] to [5], including the optical film, the polarizer, and the cellulose acylate film in this order.
[7] The polarizing plate according to any one of [1] to [6], wherein the liquid crystal compound is a compound having two or more (meth) acryl groups.

[8] The polarizing plate according to any one of [1] to [7], including a hard coat layer as an outermost layer on the optical film side as viewed from the polarizer.
[9] A method for producing a polarizing plate according to any one of [1] to [8],
(1) Prepare the following optical film materials:
A layer comprising a stretched film, an optically anisotropic layer and an optically isotropic acrylic polymer layer,
The layer made of the stretched film has a rubbed surface,
The optically anisotropic layer is a layer formed by light-irradiating a polymerizable composition containing a liquid crystal compound directly applied to the surface to polymerize the liquid crystal compound,
The acrylic polymer layer is a layer formed by curing a polymerizable composition containing (meth) acrylate applied directly to the surface of the layer formed from the polymerizable composition containing the liquid crystal compound, And,
The film thickness of the acrylic polymer layer is larger than the thickness of the optically anisotropic layer, an optical film material,
(2) peeling a layer made of a stretched film of the optical film material;
(3) The manufacturing method including laminating | stacking the optical film after peeling of the layer which consists of the said optical film material or the said stretched film on the film containing a polarizer.

[10] The optical film material is laminated on a film containing the polarizer on the surface of the acrylic polymer layer as viewed from the optical anisotropic layer, and then a layer made of the stretched film of the optical film material is peeled off. [9] The production method according to [9].
[11] The layer according to [9], wherein the layer made of the stretched film of the optical film material is peeled, and then the optical film after peeling of the layer made of the stretched film is laminated on the film containing the polarizer. Production method.

  According to the present invention, a thin and high-performance polarizing plate is provided.

It is a figure which shows the example of the polarizing plate layer structure of this invention.

Hereinafter, the present invention will be described in detail.
In the present specification, “to” is used to mean that the numerical values described before and after it are included as a lower limit value and an upper limit value. Moreover, in this specification, (meth) acrylate is used with the meaning containing both an acrylate and a methacrylate.

  In the present specification, Re (λ) and Rth (λ) respectively represent in-plane retardation and retardation in the thickness direction at a wavelength λ. Re (λ) is measured by making light having a wavelength of λ nm incident in the normal direction of the film in KOBRA 21ADH or WR (manufactured by Oji Scientific Instruments). In selecting the measurement wavelength λnm, the wavelength selection filter can be exchanged manually, or the measurement value can be converted by a program or the like.

When the film to be measured is represented by a uniaxial or biaxial refractive index ellipsoid, Rth (λ) is calculated by the following method.
Rth (λ) is Re (λ), with the in-plane slow axis (determined by KOBRA 21ADH or WR) as the tilt axis (rotation axis) (if there is no slow axis, any in-plane film The light is incident at a wavelength of λ nm from the inclined direction in steps of 10 degrees from the normal direction to 50 degrees on one side with respect to the film normal direction of the rotation axis of KOBRA 21ADH or WR is calculated based on the measured retardation value, the assumed value of the average refractive index, and the input film thickness value.

In the above case, in the case of a film having a direction in which the retardation value is zero at a certain tilt angle with the in-plane slow axis from the normal direction as the rotation axis, retardation at a tilt angle larger than the tilt angle. The value is calculated by KOBRA 21ADH or WR after changing its sign to negative.
In addition, the retardation value is measured from the two inclined directions, with the slow axis as the tilt axis (rotation axis) (when there is no slow axis, the arbitrary direction in the film plane is the rotation axis), Based on the value, the assumed value of the average refractive index, and the input film thickness value, Rth can also be calculated from the following equations (11) and (12).
Formula (11)

The above Re (θ) represents a retardation value in a direction inclined by an angle θ from the normal direction.
In formula (11), nx represents the refractive index in the slow axis direction in the plane, ny represents the refractive index in the direction perpendicular to nx in the plane, and nz represents the refractive index in the direction perpendicular to nx and ny. . d is the film thickness.

Formula (12): Rth = {(nx + ny) / 2−nz} × d
In formula (12), nx represents the refractive index in the slow axis direction in the plane, ny represents the refractive index in the direction perpendicular to nx in the plane, and nz represents the refractive index in the direction perpendicular to nx and ny. . d is the film thickness.

In the case where the film to be measured cannot be expressed by a uniaxial or biaxial refractive index ellipsoid, that is, a film having no so-called optical axis, Rth (λ) is calculated by the following method.
Rth (λ) is from −50 degrees to +50 degrees with respect to the normal direction of the film, with Re (λ) being the in-plane slow axis (determined by KOBRA 21ADH or WR) and the tilt axis (rotating axis). In each of the 10 degree steps, light of wavelength λ nm is incident from the inclined direction and measured at 11 points. Based on the measured retardation value, the assumed average refractive index, and the input film thickness value, KOBRA 21ADH or WR is calculated.
In the above measurement, the assumed value of the average refractive index may be a value in a polymer handbook (John Wiley & Sons, Inc.) or a catalog of various optical films. Those whose average refractive index is not known can be measured with an Abbe refractometer. The average refractive index values of the main optical films are exemplified below: cellulose acylate (1.48), cycloolefin polymer (1.52), polycarbonate (1.59), polymethyl methacrylate (1.49), Polystyrene (1.59). The KOBRA 21ADH or WR calculates nx, ny, and nz by inputting the assumed value of the average refractive index and the film thickness. Nz = (nx−nz) / (nx−ny) is further calculated from the calculated nx, ny, and nz.

In this specification, when there is no special mention about a measurement wavelength, a measurement wavelength is 550 nm. For example, when it is simply described as Re, Re (550) is indicated.
Further, in the present specification, regarding the angle (for example, an angle such as “90 °”) and the relationship (for example, “orthogonal”, “parallel”, “crossing at 45 °”, etc.), the technical field to which the present invention belongs. The range of allowable error is included. For example, it means that the angle is within the range of strict angle ± 10 °, and the error from the strict angle is preferably 5 ° or less, and more preferably 3 ° or less. Further, the retardation being substantially 0 means that Re (550) ≦ 10 nm and Rth (550) ≦ 10 nm, preferably Re (550) ≦ 5 nm and Rth (550) ≦ 5 nm.

[Polarizer]
The polarizing plate of the present invention includes an optical film including an optically anisotropic layer and an optically isotropic acrylic polymer layer, and a polarizer. The said optical film should just be arrange | positioned at any one surface of a polarizer, or both surfaces. It is preferable that a protective film is disposed on the other surface when the optical film is disposed on any one surface of the polarizer. A protective film may be disposed between the polarizer and the optical film. As the protective film, a cellulose acylate polymer film, an acrylic polymer film, or a cycloolefin polymer film can be used. With respect to the cellulose acylate polymer, reference can be made to the description of the cellulose acylate resin in JP2011-237474A.
In the optical film in the polarizing plate of the present invention, the optically anisotropic layer and the acrylic polymer layer may be laminated in this order from the polarizer side, or the acrylic polymer layer and the optically anisotropic layer may be laminated in this order. Good. Either the optically anisotropic layer or the acrylic polymer layer may be in direct contact with the polarizer.
An example of the layer structure of the polarizing plate of the present invention is shown in FIG.

[Optical film]
In this specification, an optical film means a film that can be used for an optical member such as various optical devices such as various display devices, light-emitting devices, and polarizing plates. In the present invention, the optical film preferably has a thickness of about 100 μm or less, 60 μm or less, 40 μm or less, 25 μm or less, 10 μm or less, or 5 μm or less. The optical film is also preferably transparent (for example, a light transmittance of 80% or more). The optical film may have low birefringence or high birefringence. Preferably it has a controlled birefringence.

[Optically anisotropic layer]
The optically anisotropic layer is a layer having optical characteristics that are not isotropic in that there is at least one incident direction in which retardation is not substantially zero when the retardation is measured. The optically anisotropic layer in the optical film used in the present invention is formed by irradiating a polymerizable composition containing a liquid crystal compound with light to polymerize the liquid crystal compound. The polymerizable composition may include any liquid crystal compound having at least one polymerizable group, and the liquid crystal composition may be polymerized by the polymerizable group by light irradiation. The polymerizable composition is preferably formed by coating on a temporary support. In particular, it is preferable that the stretched film is directly formed on the surface subjected to the rubbing treatment. The liquid crystal compound molecules in the layer can be aligned by further drying the coating layer at room temperature or by heating (for example, heating at 50 ° C. to 150 ° C., preferably 80 ° C. to 120 ° C.). It is only necessary to form an optically anisotropic layer by irradiating it with light and fixing it by polymerization.

  The film thickness of the optically anisotropic layer is 10 μm or less, less than 8 μm, 7 μm or less, 6 μm or less, 5 μm or less, 4 μm or less, 3 μm or less, 2 μm or less, 1.9 μm or less, 1.8 μm or less, 1.7 μm or less, 1 .6 μm or less, 1.5 μm or less, 1.4 μm or less, 1.3 μm or less, 1.2 μm or less, 1.1 μm or less, or 1 μm or less, 0.2 μm or more, 0.3 μm or more, 0.4 μm or more, 0 It may be 0.5 μm or more, 0.6 μm or more, 0.7 μm or more, 0.8 μm or more, or 0.9 μm or more. The film thickness of the optically anisotropic layer is preferably smaller than the film thickness of the acrylic polymer layer.

[Liquid Crystal Compound]
Examples of the liquid crystal compound include a rod-like liquid crystal compound and a disk-like liquid crystal compound.
Examples of the rod-like liquid crystal compound include azomethines, azoxys, cyanobiphenyls, cyanophenyl esters, benzoic acid esters, cyclohexanecarboxylic acid phenyl esters, cyanophenylcyclohexanes, cyano-substituted phenylpyrimidines, and alkoxy-substituted phenylpyrimidines. , Phenyldioxanes, tolanes and alkenylcyclohexylbenzonitriles are preferably used. In addition to the above low-molecular liquid crystalline molecules, high-molecular liquid crystalline molecules can also be used.

  It is more preferable to fix the orientation of the rod-like liquid crystal compound by polymerization, and examples of the polymerizable rod-like liquid crystal compound include those described in Makromol. Chem. 190, 2255 (1989), Advanced Materials 5, 107 (1993), US Pat. Nos. 4,683,327, 5,622,648, 5,770,107, WO 95/22586, 95/24455, 97 / No. 0600, No. 98/23580, No. 98/52905, JP-A-1-272551, JP-A-6-16616, JP-A-7-110469, JP-A-11-80081, and Japanese Patent Application No. 2001-64627 These compounds can be used. The polymerizable rod-like liquid crystal compound is preferably a polymerizable rod-like liquid crystal compound represented by the following general formula (1).

Formula ^{(1) Q 1 -L 1 -Cy} 1 -L 2 - (Cy 2 -L 3) n-Cy 3 -L 4 -Q 2
(In General Formula (1), Q ¹ and Q ² are each independently a polymerizable group, L ¹ and L ⁴ are each independently a divalent linking group, and L ² and L ³ are each independently a single group. A bond or a divalent linking group, Cy ¹ , Cy ² and Cy ³ are divalent cyclic groups, and n is 0, 1, 2 or 3.)

Hereinafter, the polymerizable rod-like liquid crystal compound represented by the general formula (1) will be described.
In general formula (1), Q ¹ and Q ² are each independently a polymerizable group. The polymerization reaction of the polymerizable group is preferably addition polymerization (including ring-opening polymerization) or condensation polymerization. In other words, the polymerizable group is preferably a functional group capable of addition polymerization reaction or condensation polymerization reaction. Examples of polymerizable groups are shown below.

Among the above, preferred polymerizable groups include acryl groups and methacryl groups. In particular, it is preferable that both Q ¹ and Q ² in the general formula (1) are an acryl group or a methacryl group. By using these groups, the adhesion with an acrylic polymer layer formed by curing a polymerizable composition containing (meth) acrylate tends to be improved.

In general formula (1), L ¹ and L ⁴ are each independently a divalent linking group. L ¹ and L ⁴ each independently include —O—, —S—, —CO—, —NR—, —C═N—, a divalent chain group, a divalent cyclic group, and combinations thereof. A divalent linking group selected from the group is preferred. R is an alkyl group having 1 to 7 carbon atoms or a hydrogen atom. R is preferably an alkyl group having 1 to 4 carbon atoms or a hydrogen atom, more preferably a methyl group, an ethyl group or a hydrogen atom, and most preferably a hydrogen atom.

The example of the bivalent coupling group which consists of a combination is shown below. Here, the left side is coupled to Q (Q ¹ or Q ² ), and the right side is coupled to Cy (Cy ¹ or Cy ³ ).

L-1: —CO—O—divalent chain group —O—
L-2: -CO-O-divalent chain group -O-CO-
L-3: —CO—O—divalent chain group —O—CO—O—
L-4: -CO-O-divalent chain group -O-divalent cyclic group-
L-5: -CO-O-divalent chain group -O-divalent cyclic group -CO-O-
L-6: -CO-O-divalent chain group -O-divalent cyclic group -O-CO-
L-7: -CO-O-divalent chain group-O-divalent cyclic group-divalent chain group-
L-8: -CO-O-divalent chain group -O-divalent cyclic group -divalent chain group -CO-O-
L-9: -CO-O-divalent chain group -O-divalent cyclic group -divalent chain group -O-CO-
L-10: —CO—O—divalent chain group—O—CO—divalent cyclic group—
L-11: -CO-O-divalent chain group -O-CO-divalent cyclic group -CO-O-
L-12: -CO-O-divalent chain group -O-CO-divalent cyclic group -O-CO-
L-13: —CO—O—Divalent chain group—O—CO—Divalent cyclic group—Divalent chain group—
L-14: -CO-O-divalent chain group -O-CO-divalent cyclic group -divalent chain group -CO-O-
L-15: -CO-O-divalent chain group-O-CO-divalent cyclic group-divalent chain group-O-CO-
L-16: —CO—O—divalent chain group—O—CO—O—divalent cyclic group—
L-17: -CO-O-divalent chain group -O-CO-O-divalent cyclic group -CO-O-
L-18: -CO-O-divalent chain group -O-CO-O-divalent cyclic group -O-CO-
L-19: —CO—O—Divalent chain group—O—CO—O—Divalent cyclic group—Divalent chain group—
L-20: -CO-O-divalent chain group -O-CO-O-divalent cyclic group -divalent chain group -CO-O-
L-21: -CO-O-divalent chain group -O-CO-O-divalent cyclic group -divalent chain group -O-CO-

The divalent chain group means an alkylene group, a substituted alkylene group, an alkenylene group, a substituted alkenylene group, an alkynylene group, or a substituted alkynylene group. An alkylene group, a substituted alkylene group, an alkenylene group and a substituted alkenylene group are preferred, and an alkylene group and an alkenylene group are more preferred.
The alkylene group may have a branch. The alkylene group preferably has 1 to 12 carbon atoms, more preferably 2 to 10 carbon atoms, and most preferably 2 to 8 carbon atoms.
The alkylene part of the substituted alkylene group is the same as the above alkylene group. Examples of the substituent include a halogen atom.
The alkenylene group may have a branch. The alkenylene group preferably has 2 to 12 carbon atoms, more preferably 2 to 10 carbon atoms, and most preferably 2 to 8 carbon atoms.
The alkylene part of the substituted alkylene group is the same as the above alkylene group. Examples of the substituent include a halogen atom.
The alkynylene group may have a branch. The alkynylene group preferably has 2 to 12 carbon atoms, more preferably 2 to 10 carbon atoms, and most preferably 2 to 8 carbon atoms.
The alkynylene part of the substituted alkynylene group is the same as the above alkynylene group. Examples of the substituent include a halogen atom.
Specific examples of the divalent chain group include ethylene, trimethylene, propylene, tetramethylene, 2-methyl-tetramethylene, pentamethylene, hexamethylene, octamethylene, 2-butenylene, 2-butynylene and the like.

The definition and examples of the divalent cyclic group are the same as those of Cy ¹ , Cy ² and Cy ³ described later.

In the general formula (1), L ^{2 and} L ³ are each independently a single bond or a divalent linking group. L ² and L ³ each independently include —O—, —S—, —CO—, —NR—, —C═N—, a divalent chain group, a divalent cyclic group, and combinations thereof. It is preferably a divalent linking group or a single bond selected from the group. R is an alkyl group having 1 to 7 carbon atoms or a hydrogen atom, preferably an alkyl group having 1 to 4 carbon atoms or a hydrogen atom, more preferably a methyl group, an ethyl group or a hydrogen atom. Preferably, it is a hydrogen atom. The divalent chain group and the divalent cyclic group have the same definitions as L ¹ and L ⁴ .
Preferred divalent linking groups as L ² or L ³ include —COO—, —OCO—, —OCOO—, —OCONR—, —COS—, —SCO—, —CONR—, —NRCO—, —CH _2. CH _2- , -C = C-COO-, -C = N-, -C = N-N = C-, and the like.

In the general formula (1), n is 0, 1, 2, or 3. When n is 2 or 3, two L ³ may be the same or different, and two Cy ² may be the same or different. n is preferably 1 or 2, and more preferably 1.

In the general formula (1), Cy ¹ , Cy ² and Cy ³ are each independently a divalent cyclic group.
The ring contained in the cyclic group is preferably a 5-membered ring, 6-membered ring, or 7-membered ring, more preferably a 5-membered ring or 6-membered ring, and most preferably a 6-membered ring.
The ring contained in the cyclic group may be a condensed ring. However, it is more preferably a monocycle than a condensed ring.
The ring contained in the cyclic group may be any of an aromatic ring, an aliphatic ring, and a heterocyclic ring. Examples of the aromatic ring include a benzene ring and a naphthalene ring. Examples of the aliphatic ring include a cyclohexane ring. Examples of the heterocyclic ring include a pyridine ring and a pyrimidine ring.
As the cyclic group having a benzene ring, 1,4-phenylene is preferable. As the cyclic group having a naphthalene ring, naphthalene-1,5-diyl and naphthalene-2,6-diyl are preferable. The cyclic group having a cyclohexane ring is preferably 1,4-cyclohexylene. As the cyclic group having a pyridine ring, pyridine-2,5-diyl is preferable. As the cyclic group having a pyrimidine ring, pyrimidine-2,5-diyl is preferable.
The cyclic group may have a substituent. Examples of the substituent include a halogen atom, a cyano group, a nitro group, an alkyl group having 1 to 5 carbon atoms, a halogen-substituted alkyl group having 1 to 5 carbon atoms, and an alkoxy group having 1 to 5 carbon atoms. An alkylthio group having 1 to 5 carbon atoms, an acyloxy group having 2 to 6 carbon atoms, an alkoxycarbonyl group having 2 to 6 carbon atoms, a carbamoyl group, and an alkyl-substituted carbamoyl group having 2 to 6 carbon atoms And an acylamino group having 2 to 6 carbon atoms.

  Examples of the polymerizable rod-like liquid crystal compound represented by the general formula (1) are shown below, but examples of the polymerizable rod-like liquid crystal compound of the present invention are not limited thereto.

  In addition to the polymerizable rod-shaped liquid crystal compound represented by the general formula (1), it is preferable to use at least one compound represented by the following general formula (2) as the rod-shaped liquid crystal compound.

General formula (2)
^{M 1 - (L 1) p} -Cy 1 -L 2 - (Cy 2 -L 3) n-Cy 3 - (L 4) q-M 2
(In General Formula (2), M ¹ and M ² are each independently a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, a heterocyclic group, a cyano group, a halogen, —SCN, — CF ₃ , a nitro group, or Q ¹ is represented, but at least one of M ¹ and M ² represents a group other than Q ¹ .
^{However, Q 1, L 1, L} 2, L 3, L 4, Cy 1, Cy 2, Cy 3 and n have the same meanings as the group represented by the general formula (1). P and q are 0 or 1. )

When M ¹ and M ² do not represent Q ¹ , M ¹ and M ² are preferably a hydrogen atom, a substituted or unsubstituted alkyl group, a substituted or unsubstituted aryl group, or a cyano group, more preferably , An alkyl group having 1 to 4 carbon atoms, or a phenyl group, and p and q are preferably 0.

  Moreover, as a preferable mixing ratio of the compound represented by the general formula (2) in the mixture of the polymerizable liquid crystal compound represented by the general formula (1) and the compound represented by the general formula (2), It is 0.1% -40%, More preferably, it is 1% -30%, More preferably, it is 5% -20%.

  Although the preferable example of a compound represented by General formula (2) below is shown, this invention is not limited to these.

  The discotic liquid crystalline compound is disclosed in various documents (C. Destrade et al., Mol. Crysr. Liq. Cryst., Vol. 71, page 111 (1981); edited by The Chemical Society of Japan, Quarterly Chemical Review, No. 22). , Liquid Crystal Chemistry, Chapter 5, Chapter 10 Section 2 (1994); B. Kohne et al., Angew. Chem. Soc. Chem. Comm., Page 1794 (1985); J. Zhang et al., J. Am. Chem. Soc., Vol. 116, page 2655 (1994)). The polymerization of the discotic liquid crystalline compound is described in JP-A-8-27284. In order to fix the discotic liquid crystalline compound by polymerization, it is necessary to bond a polymerizable group as a substituent to the discotic core of the discotic liquid crystalline compound. However, when the polymerizable group is directly connected to the disc-shaped core, it becomes difficult to maintain the orientation state in the polymerization reaction. Therefore, a linking group is introduced between the discotic core and the polymerizable group. That is, the photocurable discotic liquid crystalline compound is preferably a compound represented by the following formula (3).

General formula (3)
D (-LP) n
(In the general formula, D is a discotic core, L is a divalent linking group, P is a polymerizable group, and n is an integer of 4 to 12.)
Preferred specific examples of the discotic core (D), the divalent linking group (L) and the polymerizable group (P) in the formula (3) are (D1) described in JP-A No. 2001-4837, respectively. To (D15), (L1) to (L25), and (P1) to (P18), and the contents described in the publication can be preferably used.

  The compound represented by the general formulas (1) to (3) is 80% by mass or more, 90% by mass or more, or 95% by mass or more with respect to the solid content mass (mass excluding the solvent) of the polymerizable composition. Moreover, what is necessary is just to contain 99.99 mass% or less, 99.98 mass% or less, and 99.97 mass% or less. In particular, the compound containing an acrylic group or a methacryl group is 70% by mass or more, 80% by mass or more, 90% by mass or more, or 95% by mass or more, and 99.99% by mass or less, 99.98% by mass or less. 99.97% by mass or less.

  The liquid crystal compound may be fixed in any alignment state of horizontal alignment, vertical alignment, inclined alignment, and twist alignment. In the present specification, “horizontal alignment” means that in the case of a rod-like liquid crystal, the molecular long axis and the horizontal plane of the transparent support are parallel, and in the case of a disc-like liquid crystal, the disc surface of the core of the disc-like liquid crystal compound. And the horizontal plane of the transparent support is parallel, but it is not required to be strictly parallel, and in this specification, an inclination angle with the horizontal plane is less than 10 degrees. To do. The optically anisotropic layer in the optical film material of the present invention preferably contains a rod-like liquid crystal compound fixed in a horizontally aligned state.

[solvent]
As a solvent used for preparing a coating liquid when a composition containing a liquid crystal compound is prepared as a coating liquid, an organic solvent, water, or a mixed solvent thereof is preferably used. Examples of organic solvents include amides (eg, N, N-dimethylformamide), sulfoxides (eg, dimethyl sulfoxide), heterocyclic compounds (eg, pyridine), hydrocarbons (eg, benzene, hexane), alkyl halides (eg, , Chloroform, dichloromethane), esters (eg, methyl acetate, butyl acetate), ketones (eg, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone), ethers (eg, tetrahydrofuran, 1,2-dimethoxyethane), alkyl alcohols (eg, , Methanol, ethanol, propanol). Two or more kinds of solvents may be mixed and used. Among the above, alkyl halides, esters, ketones and mixed solvents thereof are preferable.
A similar solvent can be used for a composition for preparing an acrylic polymer layer described later.

[Fixed orientation]
The polymerization reaction of the liquid crystal compound may be a photopolymerization reaction. The photopolymerization reaction may be either radical polymerization or cationic polymerization, but radical polymerization is preferred. Examples of radical photopolymerization initiators include α-carbonyl compounds (described in US Pat. Nos. 2,367,661 and 2,367,670), acyloin ethers (described in US Pat. No. 2,448,828), α-hydrocarbon substituted aromatics. Aciloin compound (described in US Pat. No. 2,722,512), polynuclear quinone compound (described in US Pat. Nos. 3,046,127 and 2,951,758), a combination of triarylimidazole dimer and p-aminophenyl ketone (US Pat. No. 3,549,367) Acridine and phenazine compounds (JP-A-60-105667, US Pat. No. 4,239,850) and oxadiazole compounds (US Pat. No. 4,212,970). Examples of the cationic photopolymerization initiator include organic sulfonium salt systems, iodonium salt systems, phosphonium salt systems, and the like. Organic sulfonium salt systems are preferable, and triphenylsulfonium salts are particularly preferable. As counter ions of these compounds, hexafluoroantimonate, hexafluorophosphate, and the like are preferably used.

The amount of the photopolymerization initiator used is preferably 0.01 to 20% by mass, more preferably 0.5 to 5% by mass, based on the solid content of the coating solution. Light irradiation for the polymerization of the liquid crystal compound is preferably performed using ultraviolet rays. Irradiation energy is preferably ^{10mJ / cm 2 ~10J / cm 2} , further preferably 25~1000mJ / cm ^2. The illuminance is preferably 10~2000mW / cm ^2, more preferably 20~1500mW / cm ^2, further preferably 40~1000mW / cm ^2. The irradiation wavelength preferably has a peak at 250 to 450 nm, and more preferably has a peak at 300 to 410 nm. In order to accelerate the photopolymerization reaction, light irradiation may be performed under an inert gas atmosphere such as nitrogen or under heating conditions.

[Horizontal alignment agent]
In the polymerizable composition containing a liquid crystal compound, the compounds represented by the general formulas (1) to (3) and the general formula (4) described in paragraphs “0098” to “0105” of JP2009-69793A The molecule of the liquid crystal compound can be substantially horizontally aligned by containing at least one of a fluorine-containing homopolymer or copolymer using the monomer (1). When the liquid crystal compound is horizontally aligned, the tilt angle is preferably 0 to 5 degrees, more preferably 0 to 3 degrees, further preferably 0 to 2 degrees, and most preferably 0 to 1 degree.

The addition amount of the horizontal alignment agent is preferably 0.01 to 20% by mass, more preferably 0.01 to 10% by mass, and particularly preferably 0.02 to 1% by mass of the mass of the liquid crystal compound. In addition, the compounds represented by the general formulas (1) to (4) described in paragraphs “0098” to “0105” of JP-A-2009-69793 may be used alone or in combination of two or more. You may use together.
[Other additives]
The polymerizable composition containing a liquid crystal compound may contain other necessary additives, but preferably does not contain a so-called chiral agent.

[Acrylic polymer layer]
The optical film used in the present invention includes an acrylic polymer layer formed by curing a polymerizable composition containing (meth) acrylate. In the optical film, as the acrylic polymer layer, a polymerizable composition containing a (meth) acrylate monomer is directly applied to the surface of the optically anisotropic layer or the optically anisotropic layer before curing, and this coating layer is cured. The layer formed in this way is used. The optically anisotropic layer or the optically anisotropic layer before curing may be referred to as “a layer formed from a polymerizable composition containing a liquid crystal compound” in this specification.

As the acrylic polymer layer, an optically isotropic layer may be used. Optically isotropic means that the in-plane retardation (Re (550)) has an absolute value of 10 nm or less and the thickness direction retardation (Rth) has an absolute value of 10 nm or less.
That is, the acrylic polymer layer preferably does not include, for example, a polymer layer obtained by polymerizing a liquid crystal compound having an acrylate group, and more specifically, the liquid crystal compound has a solid content of 80% by mass or more and 70% by mass or more. 60% by mass or more, 50% by mass or more, 40% by mass or more, 30% by mass or more, 20% by mass or more, 10% by mass or more, 5% by mass or more, or 1% by mass or more. It is preferable that the polymer layer is not formed.

  Acrylic polymers include, for example, polymethyl (meth) acrylate, copolymers of (meth) acrylic acid and various esters thereof, copolymers of styrene and (meth) acrylic acid or various (meth) acrylic esters, vinyltoluene and ( Mention may be made of (meth) acrylic acid or copolymers of various (meth) acrylic acid esters. Preferred examples include copolymers of methyl (meth) acrylate and (meth) acrylic acid, copolymers of allyl (meth) acrylate and (meth) acrylic acid, benzyl (meth) acrylate and (meth) acrylic acid, and others. And multi-component copolymers with other monomers. These polymers may be used alone or in combination of two or more.

  The acrylic polymer layer may be one obtained by thermally polymerizing (meth) acrylate and other monomers, or one obtained by photopolymerization, but one obtained by photopolymerization is particularly preferred. The photopolymerization reaction should just be performed in the coating layer in which the polymeric composition containing (meth) acrylate is directly apply | coated to the layer formed from the polymeric composition containing a liquid crystal compound. The light irradiation for the photopolymerization reaction may be performed under the same conditions as the light irradiation for the polymerization of the liquid crystal compound described above, and the light irradiation for the polymerization of the liquid crystal compound simultaneously polymerizes the (meth) acrylate. May be.

As the polymerization initiator, a thermal polymerization initiator or a photopolymerization initiator is appropriately used according to the method.
As photopolymerization initiators, vicinal polyketaldonyl compounds disclosed in US Pat. No. 2,367,660, acyloin ether compounds described in US Pat. No. 2,448,828, US Pat. No. 2,722,512 An aromatic acyloin compound substituted with an α-hydrocarbon described in US Pat. Nos. 3,046,127 and 2,951,758, and a triarylimidazole described in US Pat. No. 3,549,367 A combination of a dimer and p-aminoketone, a benzothiazole compound and a trihalomethyl-s-triazine compound described in JP-B-51-48516, a trihalomethyl-triazine compound described in US Pat. No. 4,239,850, US Pat. No. 4,221,976 And the like trihalomethyl oxadiazole compounds described. In particular, trihalomethyl-s-triazine, trihalomethyloxadiazole, and triarylimidazole dimer are preferable. In addition, “polymerization initiator C” described in JP-A-11-133600 can also be mentioned as a preferable example.
Further, the amount of the polymerization initiator is preferably 0.01 to 20% by mass, more preferably 0.2 to 10% by mass, based on the solid content of the polymerizable composition for forming the acrylic polymer layer.

  In order to give the acrylic polymer layer a hard coat property, a polymer having a high Tg may be used as the polymer in the acrylic polymer layer. The Tg is preferably 50 ° C. or higher, more preferably 80 ° C. or higher, and even more preferably 100 ° C. or higher. In order to increase the Tg of the polymer, a polar group such as a hydroxyl group, a carboxylic acid group, or an amino group may be introduced. Examples of high Tg polymers include polymethyl (meth) acrylate, reaction product of alkyl (meth) acrylate such as polyethyl (meth) acrylate, copolymer of alkyl (meth) acrylate and (meth) acrylic acid, 2-hydroxyethyl Reaction products of hydroxyl group-containing (meth) acrylates such as (meth) acrylate and 2-hydroxypropyl (meth) acrylate, alkyl (meth) acrylates, hydroxyl-containing (meth) acrylates and acid anhydrides such as succinic anhydride and phthalic anhydride And a copolymer of a half ester which is a reaction product with the product.

  In order to impart hard coat properties, a layer obtained by polymerizing a layer containing at least one bifunctional or higher polymerizable monomer and a polymerizable polymer by light irradiation or heat may be used. Examples of reactive groups include (meth) acryl groups, vinyl groups, allyl groups, epoxy groups, oxetanyl groups, vinyl ether groups, and the like. As an example of the polymerizable polymer, a reaction product of a polymerizable group-containing acrylate such as glycidyl (meth) acrylate, allyl (meth) acrylate, ethylene glycol di (meth) acrylate, or glycerol 1,3-di (meth) acrylate. Examples thereof include a copolymer of a polymerizable group-containing acrylate with a reaction product (meth) acrylic acid, and a multi-component copolymer with another monomer.

  The thickness of the acrylic polymer layer is 60 μm or less, 50 μm or less, 40 μm or less, 30 μm or less, 25 μm or less, or 15 μm or less, or 2 μm or more, 3 μm or more, 3.5 μm or more, 4 μm or more, 4.5 μm or more, or 5 μm. The above is preferable. In the optical film material of the present invention, the thickness of the acrylic polymer layer is preferably larger than the thickness of the optically anisotropic layer. By making the film thickness of the acrylic polymer layer larger than the film thickness of the optically anisotropic layer, the laminate including the acrylic polymer layer and the optically anisotropic layer can be easily peeled from the stretched film. Can do. The ratio between the film thickness of the acrylic polymer layer and the film thickness of the optically anisotropic layer depends on the respective film thicknesses. For example, “film thickness of acrylic polymer layer” / “film thickness of optically anisotropic layer” However, what is necessary is just 6-5, 5-4, 4-3, 3-2, 2-1.5, 1.5-1.1, etc. Usually, it is preferable to increase the “thickness of the acrylic polymer layer” / “thickness of the optically anisotropic layer” as the respective thicknesses are smaller.

[Coating method]
Application of the composition when forming an optically anisotropic layer or an acrylic polymer layer is performed by the dip coating method, air knife coating method, spin coating method, slit coating method, curtain coating method, roller coating method, wire bar coating method. , By a gravure coating method or an extrusion coating method (US Pat. No. 2,681,294). Two or more layers may be applied simultaneously. The methods of simultaneous application are described in US Pat. Nos. 2,761,791, 2,941,898, 3,508,947, and 3,526,528 and Yuji Harasaki, Coating Engineering, page 253, Asakura Shoten (1973).

[Production method of optical film]
The optical film used in the present invention may be provided from an optical film material including a temporary support, an optically anisotropic layer, and an acrylic polymer layer. In this specification, the optical film material means a material for supplying an optical film. Specifically, any layer can be used as long as it can provide an optical film by peeling a layer made of a stretched film that functions as a temporary support.

  The optical film material preferably includes a layer made of a stretched film, an optically anisotropic layer, and an acrylic polymer layer formed by curing a polymerizable composition containing (meth) acrylate. In the optical film material, the layer made of the stretched film, the optically anisotropic layer, the optically anisotropic layer, and the acrylic polymer layer are preferably in direct contact with each other.

[Stretched film]
The stretched film used for the optical film material is not particularly limited, and may be a uniaxially stretched film or a biaxially stretched film, but is preferably a uniaxially stretched film. The stretched film is preferably a stretched thermoplastic resin film. Preferred examples of the thermoplastic resin include polyester polymers such as polyethylene terephthalate and cycloolefin polymers (for example, norbornene resins (ZEONEX, ZEONOR manufactured by Nippon Zeon Co., Ltd., ARTON manufactured by JSR Co., Ltd.), etc.). Polyethylene terephthalate (PET) is more preferable, and the stretching conditions are not particularly limited, and can be carried out with reference to the description in JP-A-2009-214441, for example.
The film thickness of the layer made of the stretched film may be about 10 μm to 1000 μm, preferably 25 μm to 250 μm, more preferably 30 μm to 90 μm.

In the optical film material of the present invention, the layer made of a stretched film has a surface subjected to rubbing treatment, and the optically anisotropic layer is directly provided on the surface subjected to rubbing treatment.
The rubbing treatment can be generally performed by rubbing the surface of a film containing a polymer as a main component several times in a certain direction with paper or cloth. A general method of rubbing is described in, for example, “Liquid Crystal Handbook” (issued by Maruzen, October 30, 2000).

As a method for changing the rubbing density, a method described in “Liquid Crystal Handbook” (published by Maruzen) can be used. The rubbing density (L) is quantified by the following formula (A).
Formula (A) L = Nl (1 + 2πrn / 60v)
In the formula (A), N is the number of rubbing, l is the contact length of the rubbing roller, r is the radius of the roller, n is the number of rotations (rpm) of the roller, and v is the stage moving speed (second speed).

In order to increase the rubbing density, the rubbing frequency should be increased, the contact length of the rubbing roller should be increased, the radius of the roller should be increased, the rotation speed of the roller should be increased, and the stage moving speed should be decreased, while the rubbing density should be decreased. To do this, you can reverse this.
In addition, the description in Japanese Patent No. 4052558 can also be referred to as conditions for the rubbing process.

  In addition to the above layers, the optical film material may contain other functional layers such as a low moisture permeable layer, a protective layer, an antistatic layer, a hard coat layer, and an adhesive layer.

The optical film material can be produced, for example, by any of the following production methods [A] to [C].
[A] (1) rubbing at least one surface of the stretched film;
(2) applying a polymerizable composition containing a liquid crystal compound to the rubbed surface of the stretched film;
(3) Applying a polymerizable composition containing (meth) acrylate directly to a layer formed from the polymerizable composition containing the liquid crystal compound, and (4) Polymerizable composition containing the liquid crystal compound. And curing the polymerizable composition containing the (meth) acrylate.

[B] The production method according to [A], wherein the curing is performed by light irradiation.
[C] The production method according to [B],
(1) rubbing at least one surface of the stretched film;
(2) coating a polymerizable composition containing a liquid crystal compound directly on the rubbed surface of the stretched film;
(2-2) The polymerizable composition containing the liquid crystal compound is irradiated with light to polymerize the liquid crystal compound to form an optically anisotropic layer.
(3) Applying the polymerizable composition containing the (meth) acrylate directly to the optically anisotropic layer,
(3-2) A production method including, in this order, forming an acrylic polymer layer by irradiating the polymerizable composition containing the (meth) acrylate with light to polymerize the (meth) acrylate.

[Polarizer]
Examples of the polarizer include an iodine polarizer, a dye polarizer using a dichroic dye, and a polyene polarizer. The iodine polarizer and the dye polarizer are generally produced using a polyvinyl alcohol film. Any polarizer may be used in the present invention. For example, the polarizer is preferably composed of polyvinyl alcohol (PVA) and a dichroic molecule. For a polarizer composed of polyvinyl alcohol (PVA) and a dichroic molecule, reference can be made to, for example, the description in JP-A-2009-237376. The film thickness of a polarizer should just be 50 micrometers or less, 30 micrometers or less are preferable and 20 micrometers or less are more preferable.

[Production Method of Polarizing Plate]
The polarizing plate used by this invention can be manufactured as follows, for example.
The layer made of the stretched film of the optical film material described above is peeled off, and the optical film after peeling of the layer made of the stretched film is laminated on a film containing a polarizer. Or the above-mentioned optical film material is laminated | stacked on the film containing a polarizer, and the layer which consists of stretched films is peeled after that. At the time of lamination, both films may be bonded with an adhesive or the like. The adhesive is not particularly limited, but is an epoxy compound curable adhesive that does not contain an aromatic ring in the molecule, as disclosed in JP-A-2004-245925, and 360-200 described in JP-A-2008-174667. An active energy ray-curable adhesive having a photopolymerization initiator having a molar extinction coefficient of 400 or more at a wavelength of 450 nm and an ultraviolet curable compound as essential components, and a (meth) acrylic compound described in JP-A-2008-174667 (A) a (meth) acrylic compound having 2 or more (meth) acryloyl groups in the molecule and (b) a hydroxyl group in the molecule, and having only a polymerizable double bond (Meth) acrylic compound and (c) phenolethylene oxide modified acrylate or nonylphenol ethylene oxide modified acrylic An active energy ray-curable adhesive containing a rate.
In addition to the polarizer, the film containing the polarizer may include a protective film, another protective film, a layer containing a polymer having a cyclic olefin structure described below, and the like.

[Layer containing polymer having cyclic olefin structure]
The polarizing plate of the present invention preferably includes a layer containing a polymer having a cyclic olefin structure. By including a layer containing a polymer having a cyclic olefin structure, moisture permeability can be imparted to the polarizing plate of the present invention. Moisture permeable means the property that water does not pass but water vapor passes.
The layer containing a polymer having a cyclic olefin structure may be an acrylic polymer layer. That is, the layer which the polymer composition containing (meth) acrylate contains the monomer which has a cyclic olefin structure, and formed the polymer with (meth) acrylate by the above-mentioned hardening may be sufficient. Alternatively, the layer containing a polymer having a cyclic olefin structure may be disposed between the optical film and the polarizer.
The film thickness of the layer containing a polymer having a cyclic olefin structure may be 30 μm or less, preferably 20 μm or less, and more preferably 10 μm or less.

[Cyclic olefin structure]
As examples of the polymer containing a cyclic olefin structure, the description in JP-A-2009-237376 can be referred to.

[Hard coat layer]
The polarizing plate of the present invention may contain a hard coat layer. The hard coat layer may be included as the outermost layer, and is preferably included in the outermost layer on the optical film side as viewed from the polarizer. As the hard coat layer, reference can be made to the description in JP-A No. 2012-103689.

In this specification, the hard coat layer refers to a layer in which the pencil hardness of the transparent support is increased by forming the layer. Practically, the pencil hardness (JIS K5400) after laminating the hard coat layer is preferably H or higher, more preferably 2H or higher, and most preferably 3H or higher. The thickness of the hard coat layer is preferably 0.4 to 35 μm, more preferably 1 to 30 μm, and most preferably 1.5 to 20 μm.
For the specific composition, reference can be made to the description in JP 2012-103689 A.

  The present invention will be described more specifically with reference to the following examples. The materials, reagents, amounts and ratios of substances, operations, and the like shown in the following examples can be appropriately changed without departing from the gist of the present invention. Therefore, the scope of the present invention is not limited to the following examples.

<Formation of Peelable Optical Film L-1>
After applying the coating liquid prepared to the formulation of the coating liquid (A) shown in Table 1 below to rubbing-treated Fujifilm PET (thickness 75 μm) using a wire bar, and drying at room temperature for 30 seconds The mixture was heated in an atmosphere of 90 ° C. for 2 minutes, and then irradiated with UV at a power of 60% for 6 to 12 seconds using a fusion D bulb (lamp 90 mW / cm) to produce an optically anisotropic layer. The average inclination angle with respect to the film surface of the rod-like liquid crystal compound was 0 °, and it was confirmed that the rod-like liquid crystal was aligned horizontally with respect to the film surface. The film thickness obtained was 1.5 μm.

<Acrylic polymer layer formation>
On the surface of the obtained optically anisotropic layer, the coating liquid prepared according to the formulation of the coating liquid (B) shown in Table 2 below was applied using a wire bar, dried at 60 ° C. for 150 seconds, and then further nitrogen. Using an air-cooled metal halide lamp (manufactured by Eye Graphics Co., Ltd.) with an oxygen concentration of about 0.1% under a purge, the coating layer was irradiated with ultraviolet rays having an illuminance of 400 mW / cm ² and an irradiation amount of 300 mJ / cm ^2. Was cured to form an acrylic polymer layer having a thickness of 5.0 μm to obtain an optical film material.

(Peeling from temporary support)
The optically anisotropic layer obtained above was peeled off from the temporary support to obtain an optical film.
When the optical film is bonded to the polarizer, it is bonded using an acrylic adhesive. When the optical film is bonded to the protective sheet, the protective sheet is subjected to corona treatment and bonded using an acrylic adhesive. .

(Formation of optical film L-2 with support)
A commercially available cellulose acylate film (Fujitack ZRD40, manufactured by FUJIFILM Corporation) was passed through a dielectric heating roll having a temperature of 60 ° C., and the film surface temperature was raised to 40 ° C. An alkaline solution having the composition shown was applied at a coating amount of 14 ml / m ² using a bar coater and transported for 10 seconds under a steam far-infrared heater manufactured by Noritake Company Limited, heated to 110 ° C. Subsequently, 3 ml / m ^{2 of} pure water was applied using the same bar coater. Next, washing with a fountain coater and draining with an air knife were repeated three times, and then transported to a drying zone at 70 ° C. for 10 seconds and dried to prepare an alkali saponified cellulose acylate film.

(Alkaline solution composition)
───────────────────────────────────
Alkaline solution composition (parts by mass)
───────────────────────────────────
Potassium hydroxide 4.7 parts by weight Water 15.8 parts by weight Isopropanol 63.7 parts by weight Surfactant SF-1: C ₁₄ H ₂₉ O (CH ₂ CH ₂ O) ₂ OH 1.0 part by weight Propylene glycol 14. 8 parts by mass ───────────────────────────────────

(Formation of alignment film)
To the long cellulose acylate film saponified as described above, an alignment film coating solution having the following composition was continuously applied with a # 14 wire bar. The film was dried with warm air of 60 ° C. for 60 seconds and further with warm air of 100 ° C. for 120 seconds to produce an alignment film.

───────────────────────────────────
Coating liquid composition for alignment layer (%)
───────────────────────────────────
Polyvinyl alcohol (PVA205, manufactured by Kuraray Co., Ltd.) 3.23
Polyvinylpyrrolidone (Luvitec K30, manufactured by BASF) 1.50
Distilled water 57.11
Methanol 38.16
───────────────────────────────────

An optically anisotropic layer was formed in the same manner as in the above example except that the base material before formation of the optically anisotropic layer (the one in which the alignment film was formed) was used to obtain an optical film L-2 with a support. . When the optical film was bonded to the protective sheet, the optical sheet was bonded to the surface of the optically anisotropic layer using an acrylic adhesive after corona treatment was performed on the protective sheet surface.

(Preparation of cyclic olefin resin sheet T-1)
A commercially available cycloolefin polymer film “ZEONOR ZF14” (manufactured by Nippon Zeon Co., Ltd.) is stretched at the stretching temperature (Tg is the glass transition temperature of the cyclic olefin resin) and the stretching ratio shown in Table 4 below, and the cyclic olefin resin Sheet T-1 was obtained.
When pasting together with a polarizer, corona treatment was performed on one surface, and the corona-treated surface was pasted using a PVA adhesive.

(Preparation of acrylic resin sheet T-2)
The acrylic resin described below was used. This acrylic resin is commercially available.
-Dianal BR88 (trade name), manufactured by Mitsubishi Rayon Co., Ltd., mass average molecular weight 1500,000 (hereinafter referred to as acrylic resin AC-1).
(UV absorber)
The ultraviolet absorber described below was used.
UV agent 1: Tinuvin 328 (Ciba Specialty Chemicals Co., Ltd.)

(Dope B preparation)
The composition described below was put into a mixing tank and stirred while heating to dissolve each component to prepare Dope B.
(Dope B composition)
Acrylic resin AC-1 100 parts by mass UV absorber UV agent 1 2 parts by mass Dichloromethane 300 parts by mass Ethanol 40 parts by mass

Using the band casting apparatus, the prepared dope was uniformly cast from a casting die to a stainless steel endless band (casting support) having a width of 2000 mm. When the residual solvent amount in the dope reached 40% by mass, the polymer film was peeled off from the casting support, transported without stretching, and dried at 130 ° C. in a drying zone. The film thickness of the obtained acrylic resin sheet T-2 was 40 μm.
When pasting together with a polarizer, corona treatment was performed on one surface, and the corona-treated surface was pasted using a PVA adhesive.

(Cellulose acylate film)
The surface of a commercially available cellulose acylate film (Fujitac 40 μm or 80 μm, manufactured by FUJIFILM Corporation) (TAC) was subjected to alkali saponification treatment. It was immersed in a 1.5 N aqueous sodium hydroxide solution at 55 ° C. for 2 minutes, washed in a water bath at room temperature, and neutralized with 0.1 N sulfuric acid at 30 ° C. Again, it was washed in a water bath at room temperature and further dried with hot air at 100 ° C. When pasting together with the polarizer, the obtained saponified surface was set to the polarizer side. A PVA adhesive was used as the adhesive.

(Production of polarizer)
A roll-like polyvinyl alcohol film having a thickness of 80 μm was continuously stretched 5 times in an aqueous iodine solution and dried to obtain a polarizing film (polarizer) having a thickness of 20 μm.

Using the obtained optical film, polarizer, and the above cyclic olefin resin sheet, acrylic resin sheet or cellulose acylate film, an optical film, a one-side polarizing plate protective sheet (including examples not used), a polarizer, the other It laminated | stacked in order of the polarizing plate protective sheet, and the polarizing plate of Examples 1-12 of the structure shown to a table | surface and Comparative Examples 1-5 was obtained.

(Curl evaluation of polarizing plate)
The obtained polarizing plate was cut out to 150 mm × 150 mm, allowed to stand still on a horizontal and smooth table with the optically anisotropic layer side up, and the following evaluation was performed. The results are shown in the table.

A: Curled strongly toward the optically anisotropic layer.
B: Curled weakly toward the optically anisotropic layer.
C: Slightly curled or hardly curled.

なお、実施例1〜１２、比較例１〜５の偏光板の膜厚は以下の表に示す通りであった。

In addition, the film thickness of the polarizing plate of Examples 1-12 and Comparative Examples 1-5 was as showing in the following tables.

DESCRIPTION OF SYMBOLS 1 Polarizer 2 Optically anisotropic layer 3 Acrylic polymer layer 4 Protective film 1
5 Hard coat layer 6 Protective film 2

Claims (11)

An optical film including an optically anisotropic layer and an optically isotropic acrylic polymer layer, and a polarizing plate including a polarizer,
The optically anisotropic layer is a layer formed by light-irradiating a polymerizable composition containing a liquid crystal compound to polymerize the liquid crystal compound,
The acrylic polymer layer is a layer formed by curing a polymerizable composition containing (meth) acrylate applied directly to the surface of the layer formed from the polymerizable composition containing the liquid crystal compound,
The polarizing plate in which the film thickness of the acrylic polymer layer is larger than the film thickness of the optically anisotropic layer. The polarizing plate of Claim 1 whose film thickness of the said optically anisotropic layer is 0.5 micrometer-5 micrometers. The polarizing plate of Claim 1 whose film thickness of the said optically anisotropic layer is 0.5 micrometer-3 micrometers. The polarizing plate according to claim 1, wherein the optically anisotropic layer and the polarizer are in direct contact. The polarizing plate according to claim 1, wherein the acrylic polymer layer and the polarizer are in direct contact. Including cellulose acylate film,
The polarizing plate as described in any one of Claims 1-5 which contains the said optical film, the said polarizer, and the said cellulose acylate film in this order. The polarizing plate according to claim 1, wherein the liquid crystal compound is a compound having two or more (meth) acryl groups. The polarizing plate as described in any one of Claims 1-7 which contains a hard-coat layer in the outermost layer by the side of the said optical film seeing from the said polarizer. It is a manufacturing method of the polarizing plate as described in any one of Claims 1-8,
(1) Prepare the following optical film materials:
A layer comprising a stretched film, an optically anisotropic layer and an optically isotropic acrylic polymer layer,
The layer made of the stretched film has a rubbed surface,
The optically anisotropic layer is a layer formed by light-irradiating a polymerizable composition containing a liquid crystal compound directly applied to the surface to polymerize the liquid crystal compound,
The acrylic polymer layer is a layer formed by curing a polymerizable composition containing (meth) acrylate applied directly to the surface of the layer formed from the polymerizable composition containing the liquid crystal compound, And,
The film thickness of the acrylic polymer layer is larger than the thickness of the optically anisotropic layer, an optical film material,
(2) peeling a layer made of a stretched film of the optical film material;
(3) The manufacturing method including laminating | stacking the optical film after peeling of the layer which consists of the said optical film material or the said stretched film on the film containing a polarizer. The optical film material is laminated on a film containing the polarizer on a surface on the acrylic polymer layer side as viewed from the optical anisotropic layer, and then a layer made of a stretched film of the optical film material is peeled off. The manufacturing method as described in. The manufacturing method according to claim 9, wherein a layer made of the stretched film of the optical film material is peeled, and then the optical film after peeling of the layer made of the stretched film is laminated on the film containing the polarizer.

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