JP2019200413A - Polarizing plate and display device - Google Patents

Abstract

To provide a circular polarizing plate which is equipped with a retardation film and has a small change in reflected hue even after being placed in a high temperature environment.SOLUTION: Disclosed is a circular polarizing plate which includes: a polarizing plate; a retardation film; and an adhesive layer. The polarizing plate includes a polarizer whose thickness is 15 μm or less. The retardation film includes a retardation layer having positive birefringence. The adhesive layer is copolymer of 80-96 wt.% of (meth)acrylic acid alkyl esters, 3-15 wt.% of ring (aromatic ring or aliphatic ring) containing monomer and 0.1-5 wt.% of polar functional group containing monomer, and is formed of adhesive composition where 0.01-5 pts.wt. of a crosslinking agent (B) is contained in 100 pts.wt. of acrylic resin (A) with a weight average molecular weight of 1,000,000-2,000,000 and molecular weight distribution of 3-7. Its gel fraction is 60-99 wt.%.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a polarizing plate and a display device.

  In recent years, image display devices typified by organic electroluminescence (hereinafter also referred to as organic EL) display devices have been rapidly spread. In the organic EL display device, a circularly polarizing plate including a polarizer and a retardation film (λ / 4 plate) is mounted. By arranging the circularly polarizing plate, reflection of external light can be prevented and the visibility of the screen can be improved.

  With the rise of organic EL display devices, there is an increasing demand for thinner image display devices. Along with this, thinner circular polarizers are also required. The circularly polarizing plate usually includes a polarizing plate (a polarizing plate including a linear polarizer) and a retardation film. Furthermore, this retardation film is made into a film by polymerizing and curing a polymerizable liquid crystal compound, for example, from a conventional resin film molded one to a one formed from a liquid crystal compound in that it can be thinned. It has been studied to change it to a new one (for example, see Patent Document 1).

JP 2017-54093 A

However, when the circularly polarizing plate is placed in a high temperature environment, the hue of the circularly polarizing plate may change from the initial state to blue or red. Such a problem may occur particularly in a circularly polarizing plate including a retardation film formed from a polymerizable liquid crystal compound. For example, when the circularly polarizing plate is rectangular, the four edges of the circularly polarizing plate are included. It was sometimes observed that the hue in the vicinity changed to blue or red, respectively.
An object of the present invention is to solve such problems, and in a circularly polarizing plate provided with a retardation film, even after being placed in a high temperature environment by using a polarizing plate having a specific configuration or a specific protective film. Another object of the present invention is to provide a circularly polarizing plate having a small in-plane change in hue.

The present invention provides a circularly polarizing plate shown in the following [1].
[1] A circularly polarizing plate having a protective film on one surface of a polarizer and a retardation film on the other surface through an adhesive layer,
The polarizer has a thickness of 15 μm or less,
The retardation film includes a retardation layer having positive birefringence,
The pressure-sensitive adhesive layer is
(A) (A-1) The following formula (I)

（式中、Ｒ₁は水素原子又はメチル基を表し、Ｒ₂は炭素数１〜１０のアルコキシ基で置換されていてもよい炭素数１〜１４のアルキル基を表す）
で示される（メタ）アクリル酸アルキルエステル８０〜９６重量％、
（Ａ−２）分子内に１個のオレフィン性二重結合と、少なくとも１個の芳香環または脂肪族環とを有する不飽和単量体３〜１５重量％、及び
（Ａ−３）極性官能基を有する不飽和単量体０.１〜５重量％
を含む単量体混合物の共重合体であって、重量平均分子量Ｍw が１００万〜２００万の範囲にあり、重量平均分子量Ｍｗと数平均分子量Ｍｎの比Ｍｗ／Ｍｎで表される分子量分布が３〜７の範囲にあるアクリル樹脂１００重量部に対し、
（Ｂ）架橋剤０.０１〜５重量部
を含有する粘着剤組成物から形成されており、６０〜９９重量％のゲル分率を有する円偏光板。

(Wherein R ₁ represents a hydrogen atom or a methyl group, and R ₂ represents an alkyl group having 1 to 14 carbon atoms which may be substituted with an alkoxy group having 1 to 10 carbon atoms)
(Meth) acrylic acid alkyl ester represented by 80 to 96% by weight,
(A-2) 3 to 15% by weight of an unsaturated monomer having one olefinic double bond and at least one aromatic ring or aliphatic ring in the molecule, and (A-3) polar functionality 0.1 to 5% by weight of unsaturated monomer having a group
A weight average molecular weight Mw in the range of 1,000,000 to 2,000,000, and a molecular weight distribution represented by a ratio Mw / Mn between the weight average molecular weight Mw and the number average molecular weight Mn. For 100 parts by weight of acrylic resin in the range of 3-7,
(B) A circularly polarizing plate formed from a pressure-sensitive adhesive composition containing 0.01 to 5 parts by weight of a crosslinking agent and having a gel fraction of 60 to 99% by weight.

Furthermore, the circularly polarizing plate of the present invention provides the following [2] to [6] as a preferred embodiment.
[2] The above (A-2) represents the following formula (II)

（式中、Ｒ₃は水素原子又はメチル基を表し、ｎは１〜８の整数であり、Ｒ₄は水素原子、アルキル基、アラルキル基又はアリール基を表す）
で示される芳香環含有（メタ）アクリル化合物の不飽和単量体である、［１］に記載の円偏光板。
［３］前記（Ａ−３）は、遊離カルボキシル基、水酸基、アミノ基及びエポキシ環からなる群より選ばれる１種以上の極性官能基を有する不飽和単量体である、［１］又は［２］に記載の円偏光板。
［４］前記（Ｂ）は、イソシアネート系化合物の架橋剤を含有する、［１］〜［３］のいずれかに記載の円偏光板。
［５］前記粘着剤組成物はさらに、前記アクリル樹脂１００重量部に対し、
（Ｃ）シラン系化合物０.０３〜１重量部
を含有する、［１］〜［４］のいずれかに記載の円偏光板。
［６］前記位相差層は、重合性液晶化合物が重合した層である［１］〜［４］のいずれかに記載の円偏光板。

(Wherein R ₃ represents a hydrogen atom or a methyl group, n is an integer of 1 to 8, and R ₄ represents a hydrogen atom, an alkyl group, an aralkyl group or an aryl group)
The circularly polarizing plate according to [1], which is an unsaturated monomer of an aromatic ring-containing (meth) acrylic compound represented by:
[3] The (A-3) is an unsaturated monomer having one or more polar functional groups selected from the group consisting of a free carboxyl group, a hydroxyl group, an amino group, and an epoxy ring, [1] or [1] 2].
[4] The circularly polarizing plate according to any one of [1] to [3], wherein (B) contains a crosslinking agent for an isocyanate compound.
[5] The pressure-sensitive adhesive composition is further based on 100 parts by weight of the acrylic resin.
(C) The circularly polarizing plate according to any one of [1] to [4], containing 0.03 to 1 part by weight of a silane compound.
[6] The circularly polarizing plate according to any one of [1] to [4], wherein the retardation layer is a layer in which a polymerizable liquid crystal compound is polymerized.

Furthermore, the present invention provides the following [7] as an application of any one of the above-mentioned circularly polarizing plates.
[7] A display device in which the circularly polarizing plate according to any one of [1] to [6] is laminated on a display element.

  According to the present invention, it is possible to provide a display device having a small in-plane change in hue, particularly reflected hue, even after being placed in a high temperature environment, and a circularly polarizing plate suitable as a member of the display device.

It is an example of the schematic sectional drawing which shows the layer structure of a circularly-polarizing plate. It is an example of the schematic sectional drawing which shows the layer structure of an organic electroluminescence display. It is a top view of the sample for evaluation.

<Definition of terms and symbols>
The definitions of terms and symbols 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 (that is, the slow axis direction),
“Ny” is a direction perpendicular to the slow axis direction in the plane, and “nz” is a refractive index in the thickness direction.
(2) In-plane retardation value An in-plane retardation value (Re [λ]) refers to an in-plane retardation value at 23 ° C. and a wavelength λ (nm). Re [λ] is Re [λ] = when the film thickness is d (nm)
It is calculated by (nx−ny) × d.
(3) Thickness direction retardation value Thickness direction retardation value (Rth [λ]) refers to a retardation value in the thickness direction of the film at 23 ° C. and wavelength λ (nm). Rth [λ] is determined by Rth [λ] = ((nx + ny) / 2−nz) × d, where d (nm) is the thickness of the film.

(4) Negative birefringence means that a slow axis appears in a direction perpendicular to the stretching direction of the resin film.
(5) Positive birefringence means that a slow axis appears in a direction parallel to the stretching direction of the resin (retardation) film.
(6) Non-oriented film The non-oriented film used in the present invention is a film satisfying an in-plane retardation value Re [590] of 10 nm or less at a wavelength of 590 nm. Furthermore, it is preferable that the retardation value Rth [590] in the thickness direction satisfy 15 nm or less because color change during the heat resistance test can be remarkably suppressed.

<Circularly polarizing plate>
The circularly polarizing plate of the present invention is a polarizing plate having a protective film on one surface of a polarizer and a retardation film on the other surface and a pressure-sensitive adhesive layer, and the thickness of the polarizer is 15 μm. The retardation film includes a retardation layer having positive birefringence, and the pressure-sensitive adhesive layer is formed from a specific pressure-sensitive adhesive composition. The polarizing plate and the retardation film can be laminated, for example, via an adhesive layer. Examples of the adhesive layer include a pressure-sensitive adhesive layer and an adhesive layer described later. Hereinafter, an example of the layer configuration of the circularly polarizing plate of the present invention will be described with reference to FIG. In addition, in FIG. 1, the adhesive bond layer for each bonding the polarizer 10 and a protective film is not illustrated. In addition, the retardation film includes a layer in which a polymerizable liquid crystal compound is polymerized (cured) (hereinafter, such a retardation film is referred to as a “liquid crystal cured film”). It is preferable because it can

  A circularly polarizing plate 100 shown in FIG. 1A has a configuration in which a protective film 11 is laminated on one surface of a polarizer 10 and a retardation film 20 is laminated on the other surface via an adhesive layer 13. Have. Although not shown, an adhesive layer may be provided between the polarizer 10 and the protective film 11. In the circularly polarizing plate of the present invention, the retardation film 20 has a layer configuration in which, for example, a liquid crystal cured film 21 and a liquid crystal cured film 22 are laminated via an adhesive layer 15 as shown in FIG. It may have a retardation film 20 (circular polarizing plate 101). One of the liquid crystal cured film 21 and the liquid crystal cured film 22 may be replaced with, for example, a retardation film formed by stretching a polycarbonate resin film. Further, the circularly polarizing plate 100 has an adhesive layer 14 on the surface of the retardation film 2 opposite to the polarizing plate 1, and the circularly polarizing plate 101 is attached to the surface of the retardation film 20 opposite to the polarizing plate 1. An agent layer 14 is provided. The pressure-sensitive adhesive layer 14 is for bonding to a display panel such as an organic EL display element.

  As shown in FIGS. 1A and 1B, in the circularly polarizing plate of the present invention, the retardation film may have one or two retardation layers. The retardation film may have three or more retardation layers as long as the circularly polarizing plate does not become extremely thick. Moreover, when there exists a liquid crystal cured film which comprises the phase difference film 20, the said liquid crystal cured film may have the orientation film for orientating a polymerizable liquid crystal compound in the manufacture stage.

  The circularly polarizing plate of the present invention can have layers other than those shown in FIGS. Examples of the layer that the circularly polarizing plate may further include a front plate and a light shielding pattern. The front plate may be arranged on the side opposite to the side on which the retardation film is laminated in the polarizing plate.

  The light shielding pattern can be formed on the surface of the front plate on the polarizing plate side. The light shielding pattern is formed on the frame (non-display area) of the image display device, and the wiring of the image display device can be prevented from being visually recognized by the user.

  The shape of the main surface of the circularly polarizing plate can be substantially rectangular. Here, the main surface means a surface having the widest area corresponding to the display surface. The term “substantially rectangular” refers to a shape that is cut or rounded so that at least one corner of the four corners (corners) is obtuse, or an end surface that is perpendicular to the main surface. A part with a recess (notch) that is partially recessed in the in-plane direction, or a part with a hole in the main surface that is hollowed into a shape such as a circle, ellipse, polygon, or a combination thereof. That you may have.

  The size of the circularly polarizing plate is not particularly limited. This size is selected according to the type and size of the display surface of a display device that uses a circularly polarizing plate. When the circularly polarizing plate is substantially rectangular, the length of the long side is preferably 6 cm or more and 35 cm or less, more preferably 10 cm or more and 30 cm or less, and the length of the short side is 5 cm or more and 30 cm or less. It is preferable that it is 6 cm or more and 25 cm or less.

<Polarizing plate>
In the circularly polarizing plate of the present invention, the polarizing plate refers to a laminate comprising a polarizer and a protective film bonded to one side of the polarizer. A circularly polarizing plate 100 and a circularly polarizing plate 101 shown in FIGS. 1A and 1B are provided with a protective film 11 on one side of a polarizer 10. The protective film provided in the polarizing plate has surface treatment layers (coating layers) such as a hard coat layer, an antiglare layer, a light diffusion layer, an antireflection layer, a low refractive index layer, an antistatic layer, and an antifouling layer, which will be described later. It may be. A polarizer and a protective film can be laminated | stacked through an adhesive bond layer or an adhesive layer, for example. The member with which a polarizing plate is provided is demonstrated below.

(1) Polarizer The polarizer provided in the polarizing plate absorbs linearly polarized light having a vibration surface parallel to the absorption axis and transmits linearly polarized light having a vibration surface orthogonal to the absorption axis (parallel to the transmission axis). It can be an absorptive polarizer having properties. As the polarizer, a polarizer in which a dichroic dye is adsorbed and oriented on a uniaxially stretched polyvinyl alcohol-based resin film can be suitably used. Such a polarizer is, for example, a step of uniaxially stretching a polyvinyl alcohol resin film (stretching treatment); a dichroic dye is adsorbed by dyeing the polyvinyl alcohol resin film with a dichroic dye (dyeing treatment). Process: It can be produced by a method including a step of treating a polyvinyl alcohol resin film adsorbed with a dichroic dye with a crosslinking agent solution such as an aqueous boric acid solution (crosslinking treatment); and a step of washing with water after the crosslinking treatment.

  As the polyvinyl alcohol resin, a saponified polyvinyl acetate resin can be used. Examples of the polyvinyl acetate resin include, in addition to polyvinyl acetate, which is a homopolymer of vinyl acetate, copolymers with other monomers copolymerizable with vinyl acetate. Specific examples of other monomers copolymerizable with vinyl acetate include unsaturated carboxylic acids, olefins, vinyl ethers, unsaturated sulfonic acids, (meth) acrylamides having ammonium groups, and the like.

  In the present specification, “(meth) acryl” means at least one selected from acryl and methacryl. The same applies to “(meth) acryloyl”, “(meth) acrylate”, and the like.

  The saponification degree of the polyvinyl alcohol resin is usually 85 to 100 mol%, preferably 98 mol% or more. The polyvinyl alcohol-based resin may be modified, and for example, polyvinyl formal or polyvinyl acetal modified with aldehydes may be used. The average degree of polymerization of the polyvinyl alcohol resin is usually 1000 to 10000, preferably 1500 to 5000. The average degree of polymerization of the polyvinyl alcohol resin can be determined according to JIS K 6726.

  A film obtained by forming such a polyvinyl alcohol resin (polyvinyl alcohol resin film) is used as a raw material (raw film) of a polarizer (polarizer). The method for forming the polyvinyl alcohol-based resin into a film is not particularly limited, and a known method is employed. The thickness of the polyvinyl alcohol resin film is not particularly limited, but in order to make the thickness of the polarizer 15 μm or less, the thickness of the polyvinyl alcohol resin film before uniaxial stretching is preferably 5 to 35 μm, more preferably. 20 μm or less. Since the circularly polarizing plate is desired to be thinner as described in the background art, it is preferable that the polarizing plate and the polarizer included in the circularly polarizing plate are also thinned.

  Uniaxial stretching of the polyvinyl alcohol-based resin film can be performed before the dichroic dye dyeing process, simultaneously with the dyeing process, or after the dyeing process. When uniaxial stretching is performed after the dyeing treatment, this uniaxial stretching may be performed before or during the crosslinking treatment. Moreover, you may uniaxially stretch in these several steps.

  In uniaxial stretching, it may be uniaxially stretched between rolls having different peripheral speeds, or may be uniaxially stretched using a hot roll. Further, the uniaxial stretching may be dry stretching in which stretching is performed in the air, or may be wet stretching in which stretching is performed in a state where a polyvinyl alcohol-based resin film is swollen using a solvent or water. The draw ratio is usually 3 to 8 times.

  As a method for dyeing a polyvinyl alcohol-based resin film with a dichroic dye (dyeing treatment), for example, a method of immersing the film in an aqueous solution containing the dichroic dye is employed. As the dichroic dye, iodine or a dichroic organic dye is used. In addition, it is preferable that the polyvinyl alcohol-type resin film performs the immersion process to water before a dyeing process.

  As the crosslinking treatment after the dyeing treatment with the dichroic dye, a method of immersing the dyed polyvinyl alcohol resin film in a boric acid-containing aqueous solution is usually employed. When iodine is used as the dichroic dye, the boric acid-containing aqueous solution preferably contains potassium iodide.

  In the circularly polarizing plate of the present invention, the thickness of the polarizer is 15 μm or less, more preferably 13 μm or less, still more preferably 10 μm or less, and even more preferably 8 μm or less. The thickness of the polarizer is usually 2 μm or more and preferably 3 μm or more. According to the study by the present inventors, it has been clarified that the change in the hue of the circularly polarizing plate is caused by the change in the retardation value of the retardation film. Furthermore, it has been clarified that the change in the retardation value of the retardation film is caused by stress when the polarizing plate undergoes dimensional shrinkage in a circularly polarizing plate placed in a high temperature environment. Therefore, from the viewpoint of reducing the influence due to the contraction of the polarizer, setting the thickness of the polarizer to 15 μm or less is effective in preventing the change in hue, particularly the reflected hue.

  As the polarizer, for example, as described in JP-A-2006-170368, a cured film obtained by polymerizing a liquid crystal compound and a dichroic dye aligned may be used. As the dichroic dye, those having absorption within a wavelength range of 380 to 800 nm can be used, and an organic dye is preferably used. Examples of the dichroic dye include azo compounds. The liquid crystal compound is a liquid crystal compound that can be polymerized while being aligned, and can have a polymerizable group in the molecule. Further, as described in WO2011 / 024891, a polarizer may be formed from a dichroic dye having liquid crystallinity. The same applies to a liquid crystal cured film that is a retardation film. However, when a polymerizable liquid crystal compound is polymerized and cured, the polymerizable liquid crystal compound is three-dimensionally polymerized and does not dissolve or dissolves in a solvent or the like. It means that it becomes difficult solid.

  The contraction force of the polarizer is preferably 2.0 N / 2 mm or less, more preferably 1.8 N / 2 mm or less, and further preferably 1.5 N / 2 mm or less. In addition, the measuring method of the contractile force of a polarizer is based on the method as described in the Example mentioned later.

(2) Protective film The circularly polarizing plate of the present invention has a polarizing plate, and this polarizing plate has a protective film on the surface of the polarizer.

  The protective film (protective film to be bonded to the polarizer) of the polarizing plate is a thermoplastic resin having translucency (preferably optically transparent), such as a chain polyolefin resin or a cyclic polyolefin resin. Polyolefin resins such as: Cellulose resins such as triacetyl cellulose and diacetyl cellulose; Polyester resins such as polyethylene terephthalate and polybutylene terephthalate; Polycarbonate resins; (Meth) acrylic resins such as methyl methacrylate resins Polystyrene resin, polyvinyl chloride resin, acrylonitrile butadiene styrene resin, acrylonitrile styrene resin, polyvinyl acetate resin, polyvinylidene chloride resin, polyamide resin, polyacetal resin, modified polyphenyle It may be a film made of maleimide resin; ether resins; polysulfone resins; poly (ether sulfone) resins; polyarylate resin; polyamideimide resin; polyimide resin.

  As the chain polyolefin-based resin, polyethylene resin (polyethylene resin which is a homopolymer of ethylene, a copolymer mainly composed of ethylene-derived polymer units), polypropylene resin (polypropylene resin which is a homopolymer of propylene, In addition to a homopolymer of a chain olefin such as a copolymer mainly composed of polymer units derived from propylene, a copolymer composed of two or more chain olefins can be exemplified.

  The cyclic polyolefin resin is a general term for resins that are polymerized using a cyclic olefin as a polymerization unit, and is described, for example, in JP-A-1-240517, JP-A-3-14882, JP-A-3-122137, and the like. Resin. Specific examples of cyclic polyolefin resins include ring-opening (co) polymers of cyclic olefins, addition polymers of cyclic olefins, copolymers of cyclic olefins and chain olefins such as ethylene and propylene (typically Are random copolymers), graft polymers obtained by modifying them with unsaturated carboxylic acids or their derivatives, and hydrides thereof. Among these, norbornene resins using norbornene monomers such as norbornene and polycyclic norbornene monomers as cyclic olefins are preferably used.

  The polyester resin is a resin having an ester bond in the main chain, and is generally a polycondensate of a polyvalent carboxylic acid or a derivative thereof and a polyhydric alcohol. As the polyvalent carboxylic acid or a derivative thereof, a divalent dicarboxylic acid or a derivative thereof can be used, and examples thereof include terephthalic acid, isophthalic acid, dimethyl terephthalate, and dimethyl naphthalenedicarboxylate. As the polyhydric alcohol, a divalent diol can be used, and examples thereof include ethylene glycol, propanediol, butanediol, neopentyl glycol, and cyclohexanedimethanol. A typical example of the polyester resin is polyethylene terephthalate which is a polycondensate of terephthalic acid and ethylene glycol.

The (meth) acrylic resin is a resin containing a compound having a (meth) acryloyl group as a main constituent monomer. Specific examples of (meth) acrylic resins include, for example, poly (meth) acrylic acid esters such as polymethyl methacrylate; methyl methacrylate- (meth) acrylic acid copolymer; methyl methacrylate- (meth) acrylic acid Ester copolymer; methyl methacrylate-acrylic ester- (meth) acrylic acid copolymer; (meth) methyl acrylate-styrene copolymer (MS resin etc.); methyl methacrylate and alicyclic hydrocarbon group And a copolymer (for example, methyl methacrylate-cyclohexyl methacrylate copolymer, methyl methacrylate- (meth) acrylate norbornyl copolymer). Preferably, a polymer based on a poly (meth) acrylic acid C _1-6 alkyl ester such as poly (meth) acrylic acid methyl is used, and more preferably methyl methacrylate is the main component (50-100). % Methyl methacrylate resin is used.

  The (meth) acrylic resin may be a (meth) acrylic resin having a lactone ring structure or a glutarimide structure. A (meth) acrylic resin having a lactone ring structure or a glutarimide structure is excellent in heat resistance. More preferred is a (meth) acrylic resin having a glutarimide structure. If a (meth) acrylic resin having a glutarimide structure is used, a (meth) acrylic resin film having low moisture permeability and a small retardation and ultraviolet transmittance can be obtained as described above. Examples of (meth) acrylic resins having a glutarimide structure (hereinafter also referred to as glutarimide resins) include, for example, JP-A-2006-309033, JP-A-2006-317560, JP-A-2006-328329, and JP-A-2006-328329. 2006-328334, JP-A 2006-337491, JP-A 2006-337492, JP-A 2006-337493, JP-A 2006-337469, JP-A 2007-009182, JP-A 2009- No. 161744. These descriptions are incorporated herein by reference.

  Preferably, the glutarimide resin includes a polymer unit represented by the following general formula (1) (hereinafter also referred to as a glutarimide unit) and a polymer unit represented by the following general formula (2) (hereinafter referred to as (meta)). Also referred to as an acrylate unit).

In Formula (1), R ¹⁰ and R ²⁰ are each independently a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, and R ³⁰ is a hydrogen atom, an alkyl group having 1 to 18 carbon atoms, or a carbon number. It is a group containing a 3-12 cycloalkyl group or a C5-C15 aromatic ring. In Formula (2), R ⁴⁰ and R ⁵⁰ are each independently a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, and R ⁶⁰ is a hydrogen atom, an alkyl group having 1 to 18 carbon atoms, or a carbon number. It is a group containing a 3-12 cycloalkyl group or a C5-C15 aromatic ring.

  The glutarimide resin may further contain a polymer unit represented by the following general formula (3) (hereinafter also referred to as an aromatic vinyl unit) as necessary.

In Formula (3), R ⁷ is a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, and R ⁸ is an aryl group having 6 to 10 carbon atoms.

In the general formula (1), preferably, R ¹ and R ² are each independently a hydrogen atom or a methyl group, and R ³ is a hydrogen atom, a methyl group, a butyl group, or a cyclohexyl group. In the general formula (1), more preferably, R ¹ is a methyl group, R ² is a hydrogen atom, and R ³ is a methyl group.

The glutarimide resin may include only a single type as a glutarimide unit, or may include a plurality of types in which R ¹ , R ² , and R ³ in the general formula (1) are different. Good.

  The glutarimide unit can be formed by imidizing the (meth) acrylic acid ester unit represented by the general formula (2). The glutarimide unit is an acid anhydride such as maleic anhydride, or a half ester of such an acid anhydride and a linear or branched alcohol having 1 to 20 carbon atoms; acrylic acid, methacrylic acid, maleic acid. It can also be formed by imidizing an α, β-ethylenically unsaturated carboxylic acid such as maleic anhydride, itaconic acid, itaconic anhydride, crotonic acid, fumaric acid and citraconic acid.

In the general formula (2), preferably, R ⁴ and R ⁵ are each independently a hydrogen atom or a methyl group, R ⁶ is a hydrogen atom or a methyl group, and more preferably R ⁴ is a hydrogen atom. An atom, R ⁵ is a methyl group, and R ⁶ is a methyl group.

The glutarimide resin may contain only a single type as a (meth) acrylic acid ester unit, or a plurality of types in which R ⁴ , R ⁵ and R ⁶ in the general formula (2) are different. May be included.

  The glutarimide resin preferably includes a polymer unit derived from styrene, α-methylstyrene, or the like as the aromatic vinyl unit represented by the general formula (3), and more preferably a polymer unit derived from styrene. May be included. By having such an aromatic vinyl unit, the positive birefringence of the glutarimide structure can be reduced, and a (meth) acrylic resin film having a lower retardation value can be obtained.

The glutarimide resin may include only a single type as an aromatic vinyl unit, or may include a plurality of types in which R ⁷ and R ⁸ are different.

The content of the glutarimide unit in the glutarimide resin is preferably changed depending on, for example, the structure of R ³ . The content of the glutarimide unit is preferably 1% by weight to 80% by weight, more preferably 1% by weight to 70% by weight, and still more preferably 1% by weight to 70% by weight based on the weight of the glutarimide resin. 60% by weight, particularly preferably 1% by weight to 50% by weight. When the content of the glutarimide unit is in such a range, a (meth) acrylic resin film having a low retardation excellent in heat resistance can be obtained.

  The content of the aromatic vinyl unit in the glutarimide resin can be appropriately set according to the purpose and desired characteristics. Depending on the application, the content of the aromatic vinyl unit may be zero. When an aromatic vinyl unit is contained, the content thereof is preferably 10% by weight to 80% by weight, more preferably 20% by weight to 80% by weight, based on the total weight of the glutarimide unit of the glutarimide resin. More preferably, it is 20 to 60% by weight, and particularly preferably 20 to 50% by weight. When the content of the aromatic vinyl unit is within such a range, a (meth) acrylic resin film having a low retardation, excellent heat resistance and mechanical strength can be obtained.

  The glutarimide resin may further be copolymerized with other structural units other than the glutarimide unit, the (meth) acrylic acid ester unit, and the aromatic vinyl unit, if necessary. Examples of other structural units include nitrile monomers such as acrylonitrile and methacrylonitrile, and structures composed of maleimide monomers such as maleimide, N-methylmaleimide, N-phenylmaleimide, and N-cyclohexylmaleimide. Units are listed. These other structural units may be directly copolymerized or graft copolymerized in the glutarimide resin.

  The cellulose ester resin is an ester of cellulose and a fatty acid. Specific examples of the cellulose ester resin include cellulose triacetate, cellulose diacetate, cellulose tripropionate, and cellulose dipropionate. Moreover, the copolymer which has multiple types of the polymer units which comprise these cellulose-ester type resins, and what modified some hydroxyl groups with the other substituent are mentioned. Among these, cellulose triacetate (triacetyl cellulose) is particularly preferable.

  A polycarbonate resin is an engineering plastic made of a polymer in which monomer units are bonded via a carbonate group.

  The protective film may contain any appropriate additive depending on the purpose. Examples of additives include hindered phenol-based, phosphorus-based and sulfur-based antioxidants, light-resistant stabilizers, ultraviolet absorbers, weather-resistant stabilizers, heat stabilizers, and other stabilizers; glass fibers, carbon fibers, etc. Reinforcing materials; near infrared absorbers; flame retardants such as tris (dibromopropyl) phosphate, triallyl phosphate, antimony oxide; antistatic agents such as anionic, cationic and nonionic surfactants; inorganic pigments, organic pigments, Colorants such as dyes; organic fillers and inorganic fillers; resin modifiers; plasticizers; lubricants; retardation reducing agents and the like. The kind, combination, content, and the like of the additive to be contained can be appropriately set according to the purpose and desired characteristics.

  The manufacturing method of a protective film is not specifically limited. Here, taking a (meth) acrylic resin film as an example, the production of the protective film will be briefly described. For example, a (meth) acrylic resin, an ultraviolet absorber, and, if necessary, other polymers and additives are sufficiently mixed by any appropriate mixing method to obtain a thermoplastic resin composition in advance. This can be formed into a film. Alternatively, a (meth) acrylic resin, an ultraviolet absorber, and if necessary, other polymers and additives are mixed in separate solutions to form a uniform mixed solution, and then film forming May be.

  In order to produce the thermoplastic resin composition, the film raw material is pre-blended with any suitable mixer such as an omni mixer, and then the obtained mixture is extruded and kneaded. In this case, the mixer used for extrusion kneading is not particularly limited. For example, any appropriate mixer such as an extruder such as a single screw extruder or a twin screw extruder or a pressure kneader may be used. it can.

  Examples of the film forming method include any appropriate film forming method such as a solution casting method (solution casting method), a melt extrusion method, a calendar method, and a compression molding method. Among these, the melt extrusion method is preferable. Since the melt extrusion method does not use a solvent, it is possible to reduce the manufacturing cost and the burden on the global environment and work environment due to the solvent.

  Examples of the melt extrusion method include a T-die method and an inflation method. The molding temperature is preferably 150 to 350 ° C., more preferably 200 to 300 ° C., and the molding temperature depends on the type of resin (thermoplastic resin) used for film molding and the type of additive used together. An appropriate range can be selected.

  When film-forming by the T-die method, a roll-shaped film is obtained by attaching a T-die to the tip of a known single-screw extruder or twin-screw extruder and winding the film extruded into a film shape. Can do. At this time, it is possible to perform uniaxial stretching by appropriately adjusting the temperature of the winding roll and adding stretching in the extrusion direction. Further, simultaneous biaxial stretching, sequential biaxial stretching, and the like can be performed by stretching the film in a direction perpendicular to the extrusion direction.

  The (meth) acrylic resin film may be an unstretched film or a stretched film. In the case of a stretched film, either a uniaxially stretched film or a biaxially stretched film may be used. In the case of a biaxially stretched film, either a simultaneous biaxially stretched film or a sequential biaxially stretched film may be used.

  Hereinafter, the case where the said (meth) acrylic-type resin film is extended | stretched is demonstrated. The stretching temperature is preferably in the vicinity of the glass transition temperature of the thermoplastic resin composition that is a film raw material, and specifically, preferably (glass transition temperature-30 ° C.) to (glass transition temperature + 30 ° C.) Preferably, it is within the range of (glass transition temperature−20 ° C.) to (glass transition temperature + 20 ° C.). If the stretching temperature is lower than (glass transition temperature −30 ° C.), the haze of the resulting film may increase, or the film may be torn or cracked, resulting in failure to obtain a predetermined stretching ratio. On the other hand, when the stretching temperature exceeds (glass transition temperature + 30 ° C.), the thickness unevenness of the resulting film becomes large, and the mechanical properties such as elongation, tear propagation strength, and fatigue resistance cannot be sufficiently improved. There is a tendency to. Furthermore, there is a tendency that troubles such as the film sticking to the roll tend to occur.

  The draw ratio is preferably 1.1 to 3 times, more preferably 1.3 to 2.5 times. When the draw ratio is in such a range, the mechanical properties such as the film elongation, tear propagation strength, and fatigue resistance can be greatly improved. As a result, it is possible to produce a film with small thickness unevenness, substantially zero birefringence (and therefore a small retardation value), and a small haze.

  The (meth) acrylic resin film can be subjected to heat treatment (annealing) or the like after the stretching treatment in order to stabilize its optical isotropy and mechanical properties. Arbitrary appropriate conditions can be employ | adopted for the conditions of heat processing.

  It is also useful to control the retardation value of the protective film to a value suitable for an image display device such as an organic EL display device or a liquid crystal display device. For example, in an in-plane switching (IPS) mode liquid crystal display device, it is preferable to use a film having a substantially zero retardation value as the protective film. A phase difference value of substantially zero means that the in-plane retardation value Re (550) at a wavelength of 550 nm is 10 nm or less, and the absolute value of the thickness direction retardation value Rth at a wavelength of 550 nm is 10 nm or less. Say. The absolute value of the thickness direction retardation value Rth at a wavelength of 480 to 750 nm is preferably 15 nm or less. In order to improve the visibility of the screen when the user wears polarized sunglasses or the like, the in-plane retardation value Re (550) at a wavelength of 550 nm may be set to 70 to 140 nm.

  For example, depending on the mode of the liquid crystal display device, the protective film may be stretched and / or shrunk to give a suitable retardation. For example, for the purpose of viewing angle compensation, a protective film having a single layer or multilayer structure can be used.

  The thickness of the protective film is usually 1 to 100 μm, but is preferably 5 to 60 μm, more preferably 10 to 55 μm, and still more preferably 15 to 40 μm from the viewpoint of strength and handleability. .

  As described above, the protective film may include a surface treatment layer (coating layer) on the outer surface (the surface opposite to the polarizer). In addition, the thickness of a protective film includes the thickness of this surface treatment layer.

  Although not shown in FIG. 1 or the like as described above, the protective film can be bonded to the polarizer through an adhesive layer or a pressure-sensitive adhesive layer, for example. As the adhesive forming the adhesive layer, a water-based adhesive, an active energy ray-curable adhesive, or a thermosetting adhesive can be used, and a water-based adhesive and an active energy ray-curable adhesive are preferable. As the pressure-sensitive adhesive layer, those described below can be used.

  Examples of the water-based adhesive include an adhesive made of a polyvinyl alcohol-based resin aqueous solution and a water-based two-component urethane emulsion adhesive. Among these, a water-based adhesive composed of a polyvinyl alcohol-based resin aqueous solution is preferable. As a polyvinyl alcohol resin used for this adhesive, in addition to a vinyl alcohol homopolymer obtained by saponifying polyvinyl acetate, which is a homopolymer of vinyl acetate, other resins that can be copolymerized with vinyl acetate are available. A polyvinyl alcohol copolymer obtained by saponifying a copolymer with a monomer, or a modified polyvinyl alcohol polymer obtained by partially modifying a hydroxyl group thereof. The polyvinyl alcohol-based aqueous adhesive may contain a crosslinking agent such as an aldehyde compound (glyoxal, etc.), an epoxy compound, a melamine-based compound, a methylol compound, an isocyanate compound, an amine compound, or a polyvalent metal salt.

  When using a water-based adhesive, it is preferable to carry out a drying step for removing water contained in the water-based adhesive after pasting the polarizer and the protective film. After the drying process, for example, a curing process for curing at a temperature of 20 to 45 ° C. may be provided.

  The active energy ray-curable adhesive is an adhesive containing a curable compound that is cured by irradiation with active energy rays such as ultraviolet rays, visible light, electron beams, and X-rays, and preferably ultraviolet curable adhesives. It is.

  The curable compound may be a cationic polymerizable curable compound or a radical polymerizable curable compound. Examples of the cationic polymerizable curable compound include epoxy compounds (compounds having one or more epoxy groups in the molecule) and oxetane compounds (one or two or more oxetane rings in the molecule). And a combination thereof. Examples of the radical polymerizable curable compound include (meth) acrylic compounds (compounds having one or more (meth) acryloyloxy groups in the molecule) and radical polymerizable double bonds. Other vinyl compounds or combinations thereof can be mentioned. A cationic polymerizable curable compound and a radical polymerizable curable compound may be used in combination. The active energy ray-curable adhesive usually further includes a cationic polymerization initiator and / or a radical polymerization initiator for initiating a curing reaction of the curable compound.

  When bonding a polarizer and a protective film, in order to improve adhesiveness, at least any one of these bonding surfaces can be subjected to a surface activation treatment. Surface activation treatment includes dry treatment such as corona treatment, plasma treatment, discharge treatment (glow discharge treatment, etc.), flame treatment, ozone treatment, UV ozone treatment, ionizing active ray treatment (ultraviolet treatment, electron beam treatment, etc.). And wet treatment such as ultrasonic treatment using a solvent such as water and acetone, saponification treatment, and anchor coat treatment. These surface activation treatments may be performed alone or in combination of two or more.

<Phase difference film>
The circularly polarizing plate of the present invention has a retardation film, and the retardation film has a retardation layer having positive birefringence. As described above, this retardation layer preferably has a layer composed of a liquid crystal cured film. In this specification, the liquid crystal cured film that is a retardation layer includes a layer that gives a retardation of λ / 2, a layer that gives a retardation of λ / 4 (positive A layer), a positive C layer, and the like. Furthermore, as described above, the retardation film may include an alignment film. This alignment film will be described later.

  Next, the liquid crystal cured film will be described. The liquid crystal cured film has a layer in which a polymerizable liquid crystal compound is cured. For example, an alignment film is provided in advance on a base material and is formed on the alignment film. The base material may have a function of supporting the alignment film and may be a long base material. This base material functions as a releasable support and can support a retardation layer for transfer. Furthermore, what has the adhesive force of the grade which the surface can peel is preferable. Examples of the substrate include resin films exemplified as the material for the protective film.

  Although it does not specifically limit as thickness of a base material, For example, it is preferable to set it as the range of 20 micrometers or more and 200 micrometers or less. When the thickness of the substrate is 20 μm or more, strength is imparted. On the other hand, when the thickness is 200 μm or less, it is possible to suppress an increase in processing waste and wear of the cutting blade when the substrate is cut into a single-wafer substrate.

  The base material may be subjected to various anti-blocking treatments. Examples of the anti-blocking process include an easy adhesion process, a process of kneading a filler and the like, an embossing process (knurling process), and the like. By applying such an anti-blocking treatment to the base material, it is possible to effectively prevent sticking of the base materials when winding the base material, so-called blocking. Such a substrate blocking prevention treatment makes it possible to produce a liquid crystal cured film with high productivity.

  When the liquid crystal cured film has a layer in which the polymerizable liquid crystal compound is cured, the layer is formed on the substrate via the alignment film. That is, the alignment film is laminated on the substrate, and the layer in which the polymerizable liquid crystal compound is cured is laminated on the alignment film.

  The alignment film is for aligning the molecular axis of the polymerizable liquid crystal compound in a specific direction, and is not limited to the vertical alignment film, and may be an alignment film for horizontally aligning the molecular axis of the polymerizable liquid crystal compound. It may be an alignment film that tilts the molecular axes of the polymerizable liquid crystal compound. The alignment film has a solvent resistance that does not dissolve by application of a composition containing a polymerizable liquid crystal compound, which will be described later, and has heat resistance in heat treatment for removing the solvent or aligning the liquid crystal compound. preferable. Examples of the alignment film include an alignment film containing an alignment polymer, a photo-alignment film, and a groove alignment film that forms an uneven pattern or a plurality of grooves on the surface and aligns them. The thickness of the alignment film is usually in the range of 10 nm to 10000 nm, preferably in the range of 10 nm to 1000 nm, more preferably 500 nm or less, and further preferably in the range of 10 nm to 200 nm. When the retardation film has an alignment film, the puncture elastic modulus is easily increased by increasing the thickness of the alignment film. By setting the thickness of the alignment film in the above range, moderate rigidity and toughness can be imparted to the polymerizable liquid crystal compound, and high film strength can be imparted.

  The resin used for the alignment film is not particularly limited as long as it is a resin used as a material for a known alignment film. A conventionally known monofunctional or polyfunctional (meth) acrylate monomer is used under a polymerization initiator. A cured product can be used. Specifically, as the (meth) acrylate monomer, for example, 2-ethylhexyl acrylate, cyclohexyl acrylate, diethylene glycol mono 2-ethylhexyl ether acrylate, diethylene glycol monophenyl ether acrylate, tetraethylene glycol monophenyl ether acrylate, trimethylolpropane triacrylate , Lauryl acrylate, lauryl methacrylate, isobornyl acrylate, isobornyl methacrylate, 2-phenoxyethyl acrylate, tetrahydrofurfuryl acrylate, 2-hydroxypropyl acrylate, benzyl acrylate, tetrahydrofurfuryl methacrylate, 2-hydroxyethyl methacrylate, benzyl methacrylate , Cyclo Hexyl methacrylate, methacrylic acid, and the like can be exemplified urethane acrylate. In addition, as resin, one of these may be sufficient and a 2 or more types of mixture may be sufficient.

  The type of the polymerizable liquid crystal compound used in the present embodiment is not particularly limited, but from its shape, it is classified into a rod-shaped type (rod-shaped liquid crystal compound) and a disk-shaped type (disk-shaped liquid crystal compound, discotic liquid crystal compound). Can be classified. Furthermore, there are a low molecular type and a high molecular type, respectively. Polymer generally means a polymer having a degree of polymerization of 100 or more (Polymer Physics / Phase Transition Dynamics, Masao Doi, 2 pages, Iwanami Shoten, 1992).

  Any polymerizable liquid crystal compound can be used for forming the retardation layer of the retardation film in the circularly polarizing plate of the present invention. Further, two or more kinds of rod-like liquid crystal compounds, two or more kinds of disk-like liquid crystal compounds, or a mixture of a rod-like liquid crystal compound and a disk-like liquid crystal compound may be used.

  As the rod-like liquid crystal compound, for example, the one described in claim 1 of JP-T-11-53019 or paragraphs [0026] to [0098] of JP-A-2005-289980 is preferably used. Can do. As the discotic liquid crystal compound, for example, those described in paragraphs [0020] to [0067] of JP-A No. 2007-108732 or paragraphs [0013] to [0108] of JP-A No. 2010-244038 are suitable. Can be used.

  Two or more kinds of polymerizable liquid crystal compounds may be used in combination. In that case, at least one of the two or more polymerizable liquid crystal compounds has two or more polymerizable groups in the molecule. As described above, the cured liquid crystal film is formed by curing and fixing the polymerizable liquid crystal compound by three-dimensional crosslinking. In this case, after becoming a liquid crystal cured film, the polymerized product (cured product) of the polymerizable liquid crystal compound contained in the liquid crystal cured film no longer needs to exhibit liquid crystallinity.

  The polymerizable group possessed by the polymerizable liquid crystal compound is preferably a functional group capable of an addition polymerization reaction such as a polymerizable ethylenically unsaturated group or a ring polymerizable group. More specifically, examples of the polymerizable group include a (meth) acryloyl group, a vinyl group, a styryl group, and an allyl group. Among these, a (meth) acryloyl group is preferable. The (meth) acryloyl group is a concept including both a methacryloyl group and an acryloyl group as described above.

  As described later, the liquid crystal cured film can be formed by coating a composition containing a polymerizable liquid crystal compound on, for example, an alignment film and irradiating active energy rays. The composition may contain a component other than the polymerizable liquid crystal compound described above. For example, it is preferable that the composition contains a polymerization initiator. As the polymerization initiator to be used, for example, a thermal polymerization initiator or a photopolymerization initiator is selected according to the type of the polymerization reaction. In order to polymerize a polymerizable liquid crystal compound by active energy ray irradiation, particularly ultraviolet irradiation, a photopolymerization initiator is preferred. Examples of the photopolymerization initiator include α-carbonyl compounds, acyloin ethers, α-hydrocarbon-substituted aromatic acyloin compounds, polynuclear quinone compounds, combinations of triarylimidazole dimers and p-aminophenyl ketones. The amount of the polymerization initiator used is preferably 0.01 to 20% by mass, more preferably 0.5 to 5% by mass, based on the total weight of the total solid content in the composition.

  In addition, the composition may contain a polymerizable monomer from the viewpoint of the uniformity of the coating film and the strength of the film. Examples of the polymerizable monomer include radically polymerizable or cationically polymerizable compounds, and an appropriate one is selected according to the type of the polymerizable liquid crystal compound to be used. Among these, a polyfunctional radically polymerizable monomer is preferable.

  In addition, as a polymerizable monomer, what can be copolymerized with the polymeric liquid crystal compound mentioned above is preferable. The amount of the polymerizable monomer used is preferably 1 to 50% by weight, more preferably 2 to 30% by weight, based on the total weight of the polymerizable liquid crystal compound.

  The composition may contain a surfactant from the viewpoint of the uniformity of the coating film and the strength of the film. Examples of the surfactant include conventionally known compounds. Of these, fluorine compounds are particularly preferred.

  The composition may contain a solvent, and in this case, an organic solvent is preferably used. Examples of the organic solvent include amide solvents (for example, N, N-dimethylformamide), sulfoxide solvents (for example, dimethyl sulfoxide), heterocyclic compound solvents (for example, pyridine), hydrocarbon solvents (for example, benzene). Hexane), alkyl halide solvents (eg, chloroform, dichloromethane), ester solvents (eg, methyl acetate, ethyl acetate, butyl acetate), ketone solvents (eg, acetone, methyl ethyl ketone), ether solvents (eg, tetrahydrofuran) 1,2-dimethoxyethane). Of these, alkyl halide solvents and ketone solvents are preferred. Two or more organic solvents may be used in combination.

  Further, the composition includes a vertical alignment promoter such as a polarizer interface side vertical alignment agent and an air interface side vertical alignment agent, and a horizontal alignment promotion such as a polarizer interface side horizontal alignment agent and an air interface side horizontal alignment agent. Various alignment agents such as an agent may be contained. Furthermore, in addition to the above components, the composition may contain an adhesion improver, a plasticizer, a polymer, and the like.

  The active energy rays include ultraviolet rays, visible light, electron beams, and X-rays, preferably ultraviolet rays. Examples of the light source of the active energy ray include a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a xenon lamp, a halogen lamp, a carbon arc lamp, a tungsten lamp, a gallium lamp, an excimer laser, and a wavelength range. Examples include LED light sources that emit light of 380 to 440 nm, chemical lamps, black light lamps, microwave-excited mercury lamps, and metal halide lamps.

When ultraviolet rays are used as the active energy rays, the irradiation intensity is usually 10 to 3,000 mW / cm ² in the case of ultraviolet B waves (wavelength range 280 to 320 nm). The ultraviolet irradiation intensity is preferably an intensity in a wavelength region effective for activation of a cationic polymerization initiator or a radical polymerization initiator. The time for irradiation with ultraviolet rays is usually 0.1 seconds to 10 minutes, preferably 0.1 seconds to 5 minutes, more preferably 0.1 seconds to 3 minutes, and further preferably 0.1 seconds. ~ 1 minute.

Ultraviolet rays can be irradiated once or several times. Depending on the polymerization initiator used in the composition, the integrated amount of light at a wavelength of 365nm is preferably in a 700 mJ / cm ² or more, more preferably, to 1,100mJ / cm ² or more, 1,300MJ / More preferably, it is not less than cm ² . Setting the integrated light amount is advantageous in increasing the polymerization rate of the polymerizable liquid crystal compound constituting the retardation film and improving the heat resistance of the retardation film. Integrated light intensity at a wavelength of 365nm is preferably in a 2,000 mJ / cm ² or less, and more preferably to 1,800mJ / cm ² or less. If the integrated light quantity becomes too high, the retardation film may be colored.

  In the circularly polarizing plate of the present invention, the thickness of the retardation layer is preferably 0.5 μm or more. Further, the thickness of the retardation layer is preferably 10 μm or less, and more preferably 5 μm or less. Sufficient durability is acquired as the thickness of a phase difference layer is more than the said lower limit. When the thickness of the retardation layer is not more than the above upper limit value, it can contribute to the thinning of the circularly polarizing plate. As for the thickness of the retardation layer, a desired in-plane retardation value and a retardation value in the thickness direction of a layer that gives a retardation of λ / 4, a layer that gives a retardation of λ / 2, or a positive C layer are obtained. Can be adjusted.

  In the retardation film of the circularly polarizing plate of the present invention, the retardation layer preferably has a liquid crystal cured film, and the liquid crystal cured film may include one layer in which a polymerizable liquid crystal compound is cured. In addition, two or more layers in which the polymerizable liquid crystal compound is cured may be included. When the retardation layer includes two layers obtained by curing the polymerizable liquid crystal compound, these two layers are a combination of a layer giving a retardation of λ / 4 and a positive C layer, or a layer giving a retardation of λ / 4 and A combination of layers giving a phase difference of λ / 2 is preferable. When the retardation layer includes two layers in which the polymerizable liquid crystal compound is cured, the layers in which the polymerizable liquid crystal compound is cured are respectively formed on the alignment film, and both are laminated via the adhesive layer or the pressure-sensitive adhesive layer. Thus, the retardation film may be manufactured. After laminating both, the substrate and the alignment film can be peeled off. The thickness of the retardation film is preferably 3 to 30 μm, and more preferably 5 to 25 μm.

The photoelastic coefficient of the retardation film is preferably 3 to 100 × 10 ⁻¹³ Pa ⁻¹ , more preferably 5 to 70 × 10 ⁻¹³ Pa ⁻¹ , and still more preferably 15 to 60 × 10 ⁻¹³ Pa ^{−1. −1} , and more preferably 20 to 60 × 10 ⁻¹³ Pa ⁻¹ . In addition, a photoelastic coefficient is the value measured by the method as described in the Example mentioned later.

<Adhesive layer>
In the circularly-polarizing plate of this invention, an adhesive layer is provided for lamination | stacking with a polarizing plate and retardation film, and bonding of the said circularly-polarizing plate with display apparatuses, such as a display panel. Hereinafter, in this pressure-sensitive adhesive layer, first, the pressure-sensitive adhesive layer 13 for bonding the polarizing plate 1 and the retardation film 20 will be described.

  The pressure-sensitive adhesive layer contains a (meth) acrylic resin (base polymer) formed from a pressure-sensitive adhesive composition containing each of the following monomers. As for the thickness of the adhesive layer 13, 3-30 micrometers is preferable, More preferably, it is 3-25 micrometers.

  Furthermore, in this invention, the adhesive layer 13 of the circularly-polarizing plate 100 shown to Fig.1 (a) or the circularly-polarizing plate 101 shown to FIG.1 (b) is an above described specific copolymer, Comprising: A weight average It is formed from a pressure-sensitive adhesive composition in which a predetermined amount of a crosslinking agent is blended with an acrylic resin having a molecular weight Mw and a molecular weight distribution Mw / Mn determined by a ratio of the weight average molecular weight and the number average molecular weight Mn within a predetermined range, and a gel content. The rate is adjusted to 60 to 99% by weight. These weight average molecular weight Mw and molecular weight distribution Mw / Mn can be determined by gel permeation chromatography (GPC). The conditions of the GPC method may be appropriate conditions depending on the type of acrylic resin that is the measurement target. Hereinafter, the adhesive composition which forms a suitable adhesive layer is demonstrated.

  First, each component which comprises this adhesive composition is demonstrated. In accordance with the above notation, the acrylic resin here is referred to as “acrylic resin (A)”, and the cross-linking agent here is referred to as “cross-linking agent (B)”. Further, the (meth) acrylic acid alkyl ester represented by the above (A-1), which induces the acrylic resin (A), is converted into “(meth) acrylic acid alkyl ester (A-1)”, (A-2) and ( The unsaturated monomer shown in A-3) may be referred to as “unsaturated monomer (A-2)” and “unsaturated monomer (A-3)”, respectively.

(1) Acrylic resin (A)
The acrylic resin (A) used in the pressure-sensitive adhesive composition for forming the pressure-sensitive adhesive layer 13 of the circularly polarizing plate of the present invention mainly comprises polymerized units derived from the (meth) acrylic acid alkyl ester represented by the formula (I). In addition to polymerized units derived from such (meth) acrylic acid alkyl esters, polymerized units derived from aromatic ring-containing monomers, and polymerized units derived from polar functional group-containing monomers Is included.

In the formula (I), which is a main polymer unit of the acrylic resin (A), R ₁ is a hydrogen atom or a methyl group, and R ₂ is an alkyl group having 1 to 14 carbon atoms. In the alkyl group represented by R ₂ , a hydrogen atom in each group may be substituted with an alkoxy group having 1 to 10 carbon atoms.

Of the (meth) acrylic acid alkyl ester (A-1) represented by the formula (I), those wherein R ₂ is an unsubstituted alkyl group are exemplified. Examples of (meth) acrylic acid alkyl ester (A-1) include linear acrylates such as methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, n-octyl acrylate, and lauryl acrylate. Alkyl acrylates; branched alkyl acrylates such as isobutyl acrylate, 2-ethylhexyl acrylate, and isooctyl acrylate; methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, methacryl Illustrative examples include linear alkyl methacrylates such as n-octyl acid and lauryl methacrylate; branched alkyl esters such as isobutyl methacrylate, 2-ethylhexyl methacrylate, and isooctyl methacrylate. That.

  Among these, n-butyl acrylate is preferable. Specifically, among the (meth) acrylic acid alkyl esters (A-1) for deriving all polymerized units constituting the acrylic resin (A), n-butyl acrylate is used. Is preferably 50% by weight or more, and satisfies the above-mentioned regulations regarding the (meth) acrylic acid alkyl ester (A-1).

As the (meth) acrylic acid alkyl ester represented by the formula (I) when R ₂ is an alkyl group substituted with an alkoxy group, that is, an alkoxyalkyl group, specifically, 2-methoxyethyl acrylate, Examples include ethoxymethyl acrylate, 2-methoxyethyl methacrylate, ethoxymethyl methacrylate, and the like.

  These (meth) acrylic acid alkyl esters may be used alone or may be copolymerized using a plurality of different ones to produce the acrylic resin (A).

  The unsaturated monomer (A-2) having one olefinic double bond and at least one aromatic ring or aliphatic ring in the molecule is a (meth) acryloyl group as a group containing an olefinic double bond. Those having the following are preferred. As an aromatic ring, not only an aromatic ring composed of only carbon atoms but also any heteroaromatic ring containing a hetero element other than carbon, but an aromatic ring composed only of carbon atoms, The unsaturated monomer which can be easily obtained from the market is preferable because it can be used as the unsaturated monomer (A-2). In addition, by using such an unsaturated monomer (A-2) containing an aromatic ring, a phase difference appears in a direction orthogonal to the stress that the pressure-sensitive adhesive receives as the polarizer contracts in a high-temperature environment. On the other hand, the retardation film develops a retardation in a direction parallel to the stress applied to the retardation film as the polarizer contracts. For this reason, the phase difference change of the phase difference film generated with the contraction of the polarizer can be canceled by the pressure-sensitive adhesive layer. For this reason, even when placed in a high temperature environment, the in-plane change of the hue, particularly the reflected hue, can be reduced. Examples of unsaturated monomer (A-2) [aromatic ring-containing acrylic compound] having one olefinic double bond and at least one aromatic ring in the molecule include benzyl (meth) acrylate, neopentyl glycol A benzoate (meth) acrylate etc. can be mentioned, A preferable thing is an aromatic ring containing (meth) acrylic compound which has a (meth) acryloyl group and is shown by said Formula (II).

  Moreover, the same effect can be obtained by using the unsaturated monomer (A-2) in which an aromatic ring is replaced with an aliphatic ring. Examples of unsaturated monomers (aliphatic ring-containing (meth) acrylic compounds) having one olefinic double bond and at least one aliphatic ring in the molecule include cyclohexyl methacrylate and cyclohexyl acrylate. Can do.

  As the unsaturated monomer (A-2), an aromatic ring-containing monomer having an aromatic ring is preferable, and among these aromatic ring-containing monomers, an aromatic ring-containing (meth) represented by the following formula (II) Acrylic compounds are particularly preferred.

（式中、Ｒ₃は水素原子またはメチル基を表し、ｎは１〜８の整数であり、Ｒ₄は水素原子、アルキル基、アラルキル基またはアリール基を表す）

(Wherein R ₃ represents a hydrogen atom or a methyl group, n is an integer of 1 to 8, and R ₄ represents a hydrogen atom, an alkyl group, an aralkyl group or an aryl group)

In the formula (II) representing the aromatic ring-containing (meth) acrylic compound, when R ₄ is an alkyl group, the carbon number thereof can be about 1 to 9, and when it is an aralkyl group, the carbon number Is about 7-11, and when it is an aryl group, the carbon number can be about 6-10. Examples of the alkyl group having 1 to 9 carbon atoms include a methyl group, a butyl group, and a nonyl group. Examples of the aralkyl group having 7 to 11 carbon atoms include benzyl group, phenethyl group, and naphthylmethyl group. Examples of the aryl group having 6 to 10 carbon atoms include a phenyl group, a tolyl group, and a naphthyl group.

Specific examples of the aromatic ring-containing (meth) acrylic compound represented by the formula (II) include 2-phenoxyethyl (meth) acrylate, 2- (2-phenoxyethoxy) ethyl (meth) acrylate, and ethylene oxide-modified nonylphenol. (Meth) acrylic acid ester, (meth) acrylic acid 2- (o-phenylphenoxy) ethyl and the like can be mentioned. These aromatic ring-containing monomers may be used alone or in combination of a plurality of different ones. Among these, (meth) acrylic acid 2-phenoxyethyl [compound of the above formula (II), R ₄ = H, n = 1], or (meth) acrylic acid 2- (o-phenylphenoxy) ethyl [above In the formula (II), R ₄ = o-phenyl, n = 1 compound]. Such an aromatic ring-containing (meth) acrylic compound is preferably used as one of unsaturated monomers (A-2) for deriving the structural unit constituting the acrylic resin (A).

  The polar functional group of the unsaturated monomer (A-3) includes a free carboxyl group, a hydroxyl group, an amino group, a heterocyclic group including an epoxy ring, and the like. The unsaturated monomer (A-3) is preferably a (meth) acrylic acid compound having a polar functional group. Specific examples thereof include unsaturated monomers having a free carboxyl group such as acrylic acid, methacrylic acid, and β-carboxyethyl acrylate; 2-hydroxyethyl (meth) acrylate, 2-hydroxy (meth) acrylate Unsaturated monomers having a hydroxyl group, such as propyl, 2- or 3-chloro-2-hydroxypropyl (meth) acrylate, and diethylene glycol mono (meth) acrylate; acryloylmorpholine, vinylcaprolactam, N-vinyl-2- Has heterocyclic groups such as pyrrolidone, tetrahydrofurfuryl (meth) acrylate, caprolactone-modified tetrahydrofurfuryl acrylate, 3,4-epoxycyclohexylmethyl (meth) acrylate, glycidyl (meth) acrylate, and 2,5-dihydrofuran That unsaturated monomer; N, such as N- dimethylaminoethyl (meth) acrylate, and the like unsaturated monomer having a different amino group and heterocyclic. The polar functional group is preferably a free carboxyl group, a hydroxyl group, an amino group, or an epoxy ring. These unsaturated monomers (A-3), which are polar functional group-containing monomers, may be used alone or in combination with a plurality of different monomers in order to produce the acrylic resin (A). Also good.

  Among these, it is preferable to use an unsaturated monomer having a hydroxyl group as one of the polar functional group-containing monomers (A-3) constituting the acrylic resin (A). In addition to the unsaturated monomer having a hydroxyl group, it is also effective to use an unsaturated monomer having another polar functional group, for example, an unsaturated monomer having a free carboxyl group.

  In the acrylic resin (A), the structural unit derived from the (meth) acrylic acid alkyl ester (A-1) represented by the formula (I) is 80 to 96% by weight, preferably 82% by weight or more. And preferably 94% by weight or less. The structural unit derived from the aromatic ring-containing monomer (A-2) is 3 to 15% by weight, preferably 5% by weight or more, more preferably 7% by weight or more, especially 8% by weight or more, Preferably it is 13 weight% or less, Furthermore, 11 weight% or less, Especially 10 weight% or less. The structural unit derived from the polar functional group-containing monomer (A-3) is 0.1 to 5% by weight, preferably 0.5% by weight or more, and preferably 3% by weight or less. .

  The acrylic resin (A) used in the present invention is a (meth) acrylic acid alkyl ester (A-1) represented by the above formula (I), an unsaturated monomer (A-2) [containing an aromatic ring. Polymer units derived from monomers different from (meth) acrylic compounds and / or aliphatic ring-containing (meth) acrylic compounds] and unsaturated monomers (A-3) [polar functional group-containing monomers]. May be included. Examples of these include structural units derived from styrene monomers, structural units derived from vinyl monomers, structural units derived from monomers having a plurality of (meth) acryloyl groups in the molecule, and the like. Can be mentioned.

  Specific examples of the styrenic monomer include styrene, methyl styrene, dimethyl styrene, trimethyl styrene, ethyl styrene, diethyl styrene, triethyl styrene, propyl styrene, butyl styrene, hexyl styrene, heptyl styrene, and octyl styrene. Alkyl styrene; halogenated styrene such as fluorostyrene, chlorostyrene, bromostyrene, dibromostyrene, and iodostyrene; and nitrostyrene, acetylstyrene, methoxystyrene, divinylbenzene, and the like.

  Specific examples of the vinyl monomer include vinyl acetate, vinyl propionate, vinyl butyrate, vinyl 2-ethylhexanoate, and vinyl fatty acid esters such as vinyl laurate; vinyl halides such as vinyl chloride and vinyl bromide; Vinylidene halides such as vinylidene chloride; nitrogen-containing aromatic vinyls such as vinylpyridine, vinylpyrrolidone, and vinylcarbazole; conjugated diene monomers such as butadiene, isoprene, and chloroprene; and acrylonitrile, methacrylonitrile, etc. be able to.

  Specific examples of the monomer having a plurality of (meth) acryloyl groups in the molecule include 1,4-butanediol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, and 1,9-nonane. Two diols in the molecule, such as diol di (meth) acrylate, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, and tripropylene glycol di (meth) acrylate A monomer having a (meth) acryloyl group; a monomer having three (meth) acryloyl groups in the molecule, such as trimethylolpropane tri (meth) acrylate;

  Monomers different from the (meth) acrylic acid alkyl ester (A-1), unsaturated monomer (A-2) and unsaturated monomer (A-3) are each independently Or two or more types can be used in combination. The acrylic resin (A) used for the pressure-sensitive adhesive is different from the (meth) acrylic acid alkyl ester (A-1), the unsaturated monomer (A-2), and the unsaturated monomer (A-3). The polymer unit derived from the monomer is usually contained in a proportion of 0 to 20 parts by weight, preferably 0 to 10 parts by weight, based on the total weight of the acrylic resin (A).

  The resin component constituting the pressure-sensitive adhesive composition may contain the acrylic resin (A) alone as described above, or may contain a resin other than the acrylic resin (A). Resins other than the acrylic resin (A) are also preferably acrylic resins. An acrylic resin other than the acrylic resin (A), for example, an acrylic resin having a structural unit derived from the (meth) acrylic acid alkyl ester of the formula (I) and not containing a polar functional group may be used. . It contains polymer units derived from the (meth) acrylic acid alkyl ester (A-1), unsaturated monomer (A-2), and unsaturated monomer (A-3) represented by the formula (I). The acrylic resin (A) is preferably 80% by weight or more, more preferably 90% by weight or more based on the total weight of the resin components.

  As the acrylic resin (A), one having a weight average molecular weight Mw in the range of 1 to 2 million in terms of standard polystyrene by gel permeation chromatography (GPC) is employed. When the weight average molecular weight in terms of standard polystyrene is 1 million or more, the adhesiveness under high temperature and high humidity is improved, and the possibility of occurrence of floating or peeling between the liquid crystal cell and the pressure-sensitive adhesive layer tends to be low. And reworkability tends to be improved. Further, when the weight average molecular weight is 2 million or less, even if the size of the polarizing plate attached to the pressure-sensitive adhesive layer changes, the pressure-sensitive adhesive layer fluctuates following the dimensional change. This is preferable because there is no difference between the brightness of the peripheral portion and the brightness of the central portion, and white spots and color unevenness tend to be suppressed.

  The molecular weight distribution represented by the ratio Mw / Mn of the weight average molecular weight Mw and the number average molecular weight Mn is in the range of 3-7. When the molecular weight distribution Mw / Mn is in the range of 3 to 7, the heat resistance of the obtained pressure-sensitive adhesive layer is improved, and when the circularly polarizing plate of the present invention is applied to a liquid crystal panel or a liquid crystal display device, these are high temperatures. Even when exposed to, it is possible to prevent problems such as white spots from occurring.

  Moreover, it is preferable that the glass transition temperature of the said acrylic resin (A) exists in the range of -10-60 degreeC for adhesive expression. This glass transition temperature can generally be measured with a differential scanning calorimeter.

  The acrylic resin (A) can be produced by various known methods such as a solution polymerization method, an emulsion polymerization method, a bulk polymerization method, and a suspension polymerization method. In the production of the acrylic resin (A), a polymerization initiator is usually used. The polymerization initiator is used in an amount of about 0.001 to 5 parts by weight with respect to a total of 100 parts by weight of all monomers used in the production of the acrylic resin (A).

  As the polymerization initiator, a thermal polymerization initiator, a photopolymerization initiator, or the like is used. Examples of the photopolymerization initiator include 4- (2-hydroxyethoxy) phenyl (2-hydroxy-2-propyl) ketone. Examples of the thermal polymerization initiator include 2,2′-azobisisobutyronitrile, 2,2′-azobis (2-methylbutyronitrile), 1,1′-azobis (cyclohexane-1-carbonitrile), 2,2'-azobis (2,4-dimethylvaleronitrile), 2,2'-azobis (2,4-dimethyl-4-methoxyvaleronitrile), dimethyl-2,2'-azobis (2-methylpropio) And azo compounds such as 2,2'-azobis (2-hydroxymethylpropionitrile); lauryl peroxide, tert-butyl hydroperoxide, benzoyl peroxide, tert-butyl peroxybenzoate, cumene hydroper Oxide, diisopropylperoxydicarbonate, dipropylperoxydicarbonate, tert-butylperoxide Organic peroxides such as xineodecanoate, tert-butyl peroxypivalate, and (3,5,5-trimethylhexanoyl) peroxide; inorganic peroxides such as potassium persulfate, ammonium persulfate, and hydrogen peroxide An oxide etc. can be mentioned. A redox initiator using a peroxide and a reducing agent in combination can also be used as the polymerization initiator.

  As a manufacturing method of an acrylic resin (A), a solution polymerization method is preferable among the above methods. The solution polymerization method will be described with specific examples. A desired monomer and an organic solvent (polymerization solvent) are mixed, a thermal polymerization initiator is added in a nitrogen atmosphere, and about 40 to 90 ° C., preferably The method of stirring at about 60-80 degreeC for about 3 to 10 hours can be mentioned. In order to control the reaction, a monomer or a thermal polymerization initiator may be added continuously or intermittently during the polymerization, or may be added in a state dissolved in an organic solvent. Here, examples of the polymerization solvent include aromatic hydrocarbons such as toluene and xylene; esters such as ethyl acetate and butyl acetate; aliphatic alcohols such as propyl alcohol and isopropyl alcohol; acetone, methyl ethyl ketone, and methyl isobutyl. Ketones such as ketones can be used.

(2) Crosslinking agent (B)
A crosslinking agent (B) is mix | blended with the above acrylic resins (A), and it is set as an adhesive composition. The crosslinking agent (B) is a compound having in the molecule at least two functional groups capable of crosslinking with the polymer unit derived from the unsaturated monomer (A-3) in the acrylic resin (A). Examples include isocyanate compounds, epoxy compounds, metal chelate compounds, aziridine compounds and the like.

  Isocyanate compounds are compounds having at least two isocyanato groups (-NCO) in the molecule, such as tolylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, diphenylmethane diisocyanate, Examples thereof include hydrogenated diphenylmethane diisocyanate, naphthalene diisocyanate, and triphenylmethane triisocyanate. In addition, adducts obtained by reacting these isocyanate compounds with polyols such as glycerol and trimethylolpropane, and those obtained by converting isocyanate compounds into dimers, trimers, and the like can also be used as crosslinking agents for pressure-sensitive adhesives. Two or more isocyanate compounds can be mixed and used.

  The epoxy compound is a compound having at least two epoxy groups in the molecule, for example, bisphenol A type epoxy resin, ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, glycerin diglycidyl ether, glycerin triglycidyl ether. 1,6-hexanediol diglycidyl ether, trimethylolpropane triglycidyl ether, N, N-diglycidylaniline, N, N, N ′, N′-tetraglycidyl-m-xylenediamine, 1,3-bis ( N, N'-diglycidylaminomethyl) cyclohexane and the like. Two or more types of epoxy compounds can be mixed and used.

  Examples of metal chelate compounds include compounds in which acetylacetone or ethyl acetoacetate is coordinated to a polyvalent metal such as aluminum, iron, copper, zinc, tin, titanium, nickel, antimony, magnesium, vanadium, chromium, and zirconium. Is mentioned.

  An aziridine-based compound is a compound having at least two skeletons of a three-membered ring composed of one nitrogen atom and two carbon atoms, also called ethyleneimine, for example, diphenylmethane-4,4′-bis ( 1-aziridinecarboxamide), toluene-2,4-bis (1-aziridinecarboxamide), triethylenemelamine, isophthaloylbis-1- (2-methylaziridine), tris-1-aziridinylphosphine oxide, hexamethylene -1,6-bis (1-aziridinecarboxamide), trimethylolpropane tris-β-aziridinylpropionate, tetramethylolmethane tris-β-aziridinylpropionate, and the like.

  Among these crosslinking agents, isocyanate compounds, especially xylylene diisocyanate, tolylene diisocyanate or hexamethylene diisocyanate, or adducts obtained by reacting these isocyanate compounds with polyols such as glycerol and trimethylolpropane, and these A dimer or trimer of an isocyanate compound or a mixture of these isocyanate compounds is preferably used. In particular, when the unsaturated monomer (A-3) has a polar functional group selected from a free carboxyl group, a hydroxyl group, an amino group, and an epoxy ring, an isocyanate compound is used as at least one of the crosslinking agent (B). It is preferable to use it. Among the above-mentioned preferred isocyanate compounds, tolylene diisocyanate, an adduct obtained by reacting tolylene diisocyanate with a polyol, a dimer of tolylene diisocyanate, and a trimer of tolylene diisocyanate, hexamethylene diisocyanate, hexa Examples thereof include adducts obtained by reacting methylene diisocyanate with a polyol, hexamethylene diisocyanate dimer, and hexamethylene diisocyanate trimer.

  A crosslinking agent (B) is mix | blended in the ratio of 0.01-5 weight part with respect to 100 weight part of acrylic resins (A). The amount of the crosslinking agent (B) is preferably about 0.1 to 5 parts by weight, more preferably about 0.2 to 3 parts by weight with respect to 100 parts by weight of the acrylic resin (A). It is preferable that the amount of the crosslinking agent (B) with respect to 100 parts by weight of the acrylic resin (A) is 0.01 parts by weight or more, particularly 0.1 parts by weight or more because the durability of the pressure-sensitive adhesive layer tends to be improved. Moreover, it is preferable that it is 5 parts by weight or less because so-called white spots become inconspicuous.

(3) Other components constituting the pressure-sensitive adhesive composition The pressure-sensitive adhesive composition for forming the pressure-sensitive adhesive layer contains a silane compound (C) in order to improve the adhesion of the pressure-sensitive adhesive layer itself. In particular, it is preferable to contain the silane compound (C) in the acrylic resin (A) before blending the crosslinking agent.

  Examples of the silane compound (C) include vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (2-methoxyethoxy) silane, N- (2-aminoethyl) -3-aminopropylmethyldimethoxysilane, N- ( 2-aminoethyl) -3-aminopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropylmethyldimethoxysilane, 2- (3,4-epoxy (Cyclohexyl) ethyltrimethoxysilane, 3-chloropropylmethyldimethoxysilane, 3-chloropropyltrimethoxysilane, 3-methacryloyloxypropyltrimethoxysilane, 3-mercaptopropyltrimethoxysilane, 3-glycidoxypropyltrimeth Shishiran, 3-glycidoxypropyl triethoxysilane, 3-glycidoxypropyl dimethoxymethyl silane, such as 3-glycidoxypropyl ethoxy dimethyl silane. Two or more silane compounds (C) may be used.

  The silane compound (C) may be of a silicone oligomer type. When the silicone oligomer is shown in the form of (monomer)-(monomer) copolymer, for example, the following can be mentioned.

  3-mercaptopropyltrimethoxysilane-tetramethoxysilane copolymer, 3-mercaptopropyltrimethoxysilane-tetraethoxysilane copolymer, 3-mercaptopropyltriethoxysilane-tetramethoxysilane copolymer, and 3-mercaptopropyltriethoxysilane-tetraethoxy A copolymer containing a mercaptopropyl group, such as a silane copolymer;

  Mercaptomethyl groups such as mercaptomethyltrimethoxysilane-tetramethoxysilane copolymer, mercaptomethyltrimethoxysilane-tetraethoxysilane copolymer, mercaptomethyltriethoxysilane-tetramethoxysilane copolymer, and mercaptomethyltriethoxysilane-tetraethoxysilane copolymer. Containing copolymers;

  3-methacryloyloxypropyltrimethoxysilane-tetramethoxysilane copolymer, 3-methacryloyloxypropyltrimethoxysilane-tetraethoxysilane copolymer, 3-methacryloyloxypropyltriethoxysilane-tetramethoxysilane copolymer, 3-methacryloyloxypropyltriethoxysilane -Tetraethoxysilane copolymer, 3-methacryloyloxypropylmethyldimethoxysilane-tetramethoxysilane copolymer, 3-methacryloyloxypropylmethyldimethoxysilane-tetraethoxysilane copolymer, 3-methacryloyloxypropylmethyldiethoxysilane-tetramethoxysilane copolymer, and 3-Methacryloyloxypropylmethyldiethoxysilane-tetra Toki bell Ranco polymers such as, methacryloyloxypropyl group containing copolymers;

  3-acryloyloxypropyltrimethoxysilane-tetramethoxysilane copolymer, 3-acryloyloxypropyltrimethoxysilane-tetraethoxysilane copolymer, 3-acryloyloxypropyltriethoxysilane-tetramethoxysilane copolymer, 3-acryloyloxypropyltriethoxysilane -Tetraethoxysilane copolymer, 3-acryloyloxypropylmethyldimethoxysilane-tetramethoxysilane copolymer, 3-acryloyloxypropylmethyldimethoxysilane-tetraethoxysilane copolymer, 3-acryloyloxypropylmethyldiethoxysilane-tetramethoxysilane copolymer, and 3-acryloyloxypropylmethyldiethoxysilane-tetraethoxysilane Rimmer such as, acryloyloxypropyl group-containing copolymer;

  Vinyltrimethoxysilane-tetramethoxysilane copolymer, vinyltrimethoxysilane-tetraethoxysilane copolymer, vinyltriethoxysilane-tetramethoxysilane copolymer, vinyltriethoxysilane-tetraethoxysilane copolymer, vinylmethyldimethoxysilane-tetramethoxysilane copolymer, Vinyl group-containing copolymers such as vinylmethyldimethoxysilane-tetraethoxysilane copolymer, vinylmethyldiethoxysilane-tetramethoxysilane copolymer, and vinylmethyldiethoxysilane-tetraethoxysilane copolymer;

  3-aminopropyltrimethoxysilane-tetramethoxysilane copolymer, 3-aminopropyltrimethoxysilane-tetraethoxysilane copolymer, 3-aminopropyltriethoxysilane-tetramethoxysilane copolymer, 3-aminopropyltriethoxysilane-tetraethoxysilane Copolymer, 3-aminopropylmethyldimethoxysilane-tetramethoxysilane copolymer, 3-aminopropylmethyldimethoxysilane-tetraethoxysilane copolymer, 3-aminopropylmethyldiethoxysilane-tetramethoxysilane copolymer, and 3-aminopropylmethyldiethoxy Amino group-containing copolymers such as silane-tetraethoxysilane copolymers.

  These silane compounds (C) are often liquids. The compounding amount of the silane compound (C) in the pressure-sensitive adhesive composition is usually 100 parts by weight of the nonvolatile content of the acrylic resin (A) (the total amount when two or more acrylic resins (A) are used). The amount is about 0.01 to 10 parts by weight, preferably 0.03 to 1 part by weight. It is preferable that the amount of the silane compound relative to 100 parts by weight of the acrylic resin (A) is 0.01 parts by weight or more, particularly 0.03 parts by weight or more because adhesion is improved. Moreover, when the amount is 10 parts by weight or less, particularly 1 part by weight or less, it is preferable because bleeding out of the silane compound from the pressure-sensitive adhesive layer tends to be suppressed.

  The pressure-sensitive adhesive composition described above further includes a crosslinking catalyst, a weather resistance stabilizer, a tackifier, a plasticizer, a softening agent, a dye, a pigment, an inorganic filler, an antistatic agent, and a resin (for example, other than the acrylic resin (A)) Resin) or the like. It is also useful to form a harder pressure-sensitive adhesive layer by blending the pressure-sensitive adhesive composition with an ultraviolet curable compound and forming the pressure-sensitive adhesive layer by irradiating it with ultraviolet rays and curing it. Moreover, if a crosslinking catalyst is mix | blended with an adhesive composition with a crosslinking agent composition, an adhesive layer can be prepared by aging for a short time, In the circularly-polarizing plate of this invention, between a polarizing plate and an adhesive layer. Occurrence of floating or peeling or foaming in the pressure-sensitive adhesive layer can be suppressed, and reworkability can be further improved. Examples of the crosslinking catalyst include amine compounds such as hexamethylenediamine, ethylenediamine, polyethyleneimine, hexamethylenetetramine, diethylenetriamine, triethylenetetramine, isophoronediamine, trimethylenediamine, polyamino resin, and melamine resin. When an isocyanate compound is used as the crosslinking agent (B), an amine compound is suitable as a crosslinking catalyst.

  Each of these components constituting the pressure-sensitive adhesive composition is mixed with the essential components acrylic resin (A) and cross-linking agent (B) in a state dissolved in a solvent as necessary to form a pressure-sensitive adhesive composition. Can do. This can be applied on a suitable substrate and dried to form an adhesive layer.

<Gel fraction of adhesive layer>
In the present invention, as described above, the pressure-sensitive adhesive layer has a gel fraction of 60 to 99% by weight. It is preferable that the gel fraction of the pressure-sensitive adhesive layer is 60% by weight or more because durability of the pressure-sensitive adhesive layer is improved. Moreover, since it is easy to manufacture that a gel fraction is 99 weight% or less, it is preferable. Here, the gel fraction is a value measured according to the following (I) to (IV).

(I) An adhesive layer having an area of about 8 cm × about 8 cm and a metal mesh made of SUS304 (with a weight of Wm) of about 10 cm × about 10 cm are bonded together.
(II) Weigh the pasted material obtained in (I) above, weigh it Ws, then fold it 4 times so as to wrap the adhesive layer and weigh it with a stapler (stapler) The weight is Wb.
(III) The mesh stapled in (II) above is placed in a glass container, and 60 mL of ethyl acetate is added and immersed, and then the glass container is stored at room temperature for 3 days.
(IV) The mesh is taken out from the glass container, dried at 120 ° C. for 24 hours, weighed, the weight is taken as Wa, and the gel fraction is calculated based on the following formula.
Gel fraction (% by weight) = [{Wa− (Wb−Ws) −Wm} / (Ws−Wm)] × 100

  The gel fraction of the pressure-sensitive adhesive layer can be adjusted by, for example, the type of acrylic resin (A) and the type and amount of the crosslinking agent (B) contained in the pressure-sensitive adhesive composition. Specifically, if the amount of the polymerization unit derived from the unsaturated monomer (A-3) in the acrylic resin (A) is increased or the amount of the crosslinking agent (B) in the pressure-sensitive adhesive composition is increased, Since the gel fraction becomes high, the amount of the polymer unit having a polar functional group and / or the crosslinking agent (B) such as a polymer unit derived from the unsaturated monomer (A-3) constituting the acrylic resin (A). The gel fraction may be adjusted by The amount of the polymerization unit derived from the unsaturated monomer (A-3) in the acrylic resin (A) is from 0.1 to 5% by weight with other components constituting the acrylic resin (A). What is necessary is just to select and adjust so that a gel fraction may become the said range by the combination and combination with the kind and quantity of a crosslinking agent (B). On the other hand, about the quantity of a crosslinking agent (B), the mixing | blending of the crosslinking agent with respect to 100 weight part (the total amount when using two or more types of acrylic resins (A)) of the non volatile matter of the acrylic resin which comprises an adhesive layer The amount is preferably selected from the range of about 0.1 to 5 parts by weight according to the type of acrylic resin.

  As described above, the pressure-sensitive adhesive layer 13 for bonding the polarizing plate 1 and the retardation film 20 has been described. For forming the pressure-sensitive adhesive layer 14 for bonding the display panel and the circularly polarizing plate of the present invention, acrylic is used. An adhesive composition containing the resin (A) and the crosslinking agent (B) can also be used.

  For the formation of the pressure-sensitive adhesive layer 14, a material other than the pressure-sensitive adhesive composition containing the acrylic resin (A) and the crosslinking agent (B) can be used. Here, it will be briefly described that a conventionally known pressure-sensitive adhesive layer can be applied to the pressure-sensitive adhesive layer 14 including known ones.

  The pressure-sensitive adhesive layer 14 can be formed of a pressure-sensitive adhesive composition mainly composed of a resin such as (meth) acrylic, rubber-based, urethane-based, ester-based, silicone-based, or polyvinyl ether-based. Among these, from the viewpoint of obtaining a pressure-sensitive adhesive layer excellent in transparency, weather resistance, heat resistance and the like, a pressure-sensitive adhesive composition having a (meth) acrylic resin as a base polymer is preferable. The pressure-sensitive adhesive composition may be an active energy ray curable type or a thermosetting type. As with the pressure-sensitive adhesive layer 13, the thickness of the pressure-sensitive adhesive layer 14 is usually preferably 3 to 30 μm, and more preferably 3 to 25 μm.

  Examples of suitable (meth) acrylic resin (base polymer) used in the pressure-sensitive adhesive composition include butyl (meth) acrylate, ethyl (meth) acrylate, isooctyl (meth) acrylate, and (meth) acrylic. A polymer or copolymer having one or more (meth) acrylic acid esters such as 2-ethylhexyl acid as a monomer is preferably used. The base polymer is preferably copolymerized with a polar monomer. Examples of polar monomers include (meth) acrylic acid, 2-hydroxypropyl (meth) acrylate, hydroxyethyl (meth) acrylate, (meth) acrylamide, N, N-dimethylaminoethyl (meth) acrylate, glycidyl ( Mention may be made of monomers having a carboxyl group, a hydroxyl group, an amide group, an amino group, an epoxy group and the like, such as (meth) acrylate.

  The pressure-sensitive adhesive composition may contain only the base polymer, but usually further contains a crosslinking agent. As a crosslinking agent, a metal ion having a valence of 2 or more, which forms a carboxylic acid metal salt with a carboxyl group; a polyamine compound, which forms an amide bond with a carboxyl group; Examples thereof include epoxy compounds and polyols that form ester bonds with carboxyl groups; polyisocyanate compounds that form amide bonds with carboxyl groups. Of these, polyisocyanate compounds are preferred.

  In the above, the suitable layer structure and the structure of each layer were demonstrated about the circularly-polarizing plate of this invention. Then, the display apparatus provided with the circularly-polarizing plate of this invention is demonstrated.

<Front plate>
The front plate is disposed on the viewing side of the display device. The front plate can be laminated on the polarizing plate via an adhesive layer. Examples of the adhesive layer include the aforementioned pressure-sensitive adhesive layer and adhesive layer. 2A and 2B show a cross-sectional structure of a display device including the circularly polarizing plate shown in FIGS. 1A and 1B. The front plate 4 can be laminated on the protective film 11 in the polarizing plate 1 via the pressure-sensitive adhesive layer 16. 2C and 2D show the cross-sectional structure of the display device including the circularly polarizing plate of FIGS. 1C and 1D, as in FIG.

  As the front plate, either a glass plate or a resin film may be used, and at least one surface thereof may include a hard coat layer. As a glass plate, what consists of highly transmissive glass and tempered glass can be used, for example. In particular, when a thin transparent surface material is used, a glass plate subjected to chemical strengthening is preferable. The glass plate can have a thickness of, for example, 100 μm to 5 mm.

  When the front plate is a resin film, it is not stiff like a glass plate and can have flexible characteristics. When using a resin film as a front plate, the resin film preferably has a hard coat layer, and the thickness of the hard coat layer is not particularly limited, and may be, for example, 5 to 100 μm.

  Resin films include cycloolefin derivatives having units of monomers containing cycloolefin, such as norbornene or polycyclic norbornene monomers, cellulose (diacetyl cellulose, triacetyl cellulose, acetyl cellulose butyrate, isobutyl ester cellulose) , Propionyl cellulose, butyryl cellulose, acetyl propionyl cellulose) ethylene-vinyl acetate copolymer, polycycloolefin, polyester, polystyrene, polyamide, polyetherimide, polyacryl, polyimide, polyamideimide, polyethersulfone, polysulfone, polyethylene, Polypropylene, polymethylpentene, polyvinyl chloride, polyvinylidene chloride, polyvinyl alcohol, polyvinyl acetal, polyether Ketones, polyether ether ketone, polyether sulfone, polymethyl methacrylate, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polycarbonate, polyurethane, or a film formed of a polymer such as epoxy. As the resin film, an unstretched, uniaxial or biaxially stretched film can be used. These polymers can be used alone or in admixture of two or more. As the resin film, a polyamide-imide film or polyimide film excellent in transparency and heat resistance, a uniaxial or biaxially stretched polyester film, a cycloolefin-based derivative film that is excellent in transparency and heat resistance and can cope with an increase in size of the film Polymethyl methacrylate films and triacetyl cellulose and isobutyl ester cellulose films having no transparency and optical anisotropy are preferred. The thickness of the resin film may be 5 to 200 μm, preferably 20 to 100 μm.

  In the resin film having a hard coat layer, the hard coat layer can be formed by curing a hard coat composition containing a reactive material that forms a cross-linked structure by irradiation with light or heat energy. The hard coat layer can be formed by curing a hard coat composition containing a photocurable (meth) acrylate monomer, or an oligomer and a photocurable epoxy monomer, or an oligomer at the same time. The photocurable (meth) acrylate monomer may include one or more selected from the group consisting of epoxy (meth) acrylate, urethane (meth) acrylate, and polyester (meth) acrylate. The epoxy (meth) acrylate can be obtained by reacting an epoxy compound with a carboxylic acid having a (meth) acryloyl group.

  The hard coat composition may further include one or more selected from the group consisting of a solvent, a photoinitiator, and an additive. The additive may include one or more selected from the group consisting of inorganic nanoparticles, leveling agents, and stabilizers. In addition, as each component generally used in this technical field, for example, an antioxidant, a UV absorber, a surfactant, a lubricant, an antifouling agent and the like can be further included.

  Thus, the circularly polarizing plate of the present invention in which the front plate 4 is bonded via the pressure-sensitive adhesive layer 16 is further bonded to the display panel 3 via the pressure-sensitive adhesive layer 14 and a member constituting the display device. Become. Such a display panel is a liquid crystal panel when the display device is a liquid crystal display device, and an organic EL display panel including an organic EL light emitting element when the display device is an organic EL display device. The pressure-sensitive adhesive layer 16 may be the same as the pressure-sensitive adhesive layer 14.

<Shading pattern>
The light shielding pattern can be provided as at least part of a bezel or a housing of a display device to which the front plate or the front plate is applied. The light shielding pattern can be formed on the display element side of the front plate. The light shielding pattern can hide each wiring of the display device so that it is not visually recognized by the user. The color and / or material of the light shielding pattern is not particularly limited, and can be formed from resin materials having various colors such as black, white, and gold. In one embodiment, the thickness of the light shielding pattern may be 2 μm to 50 μm, preferably 4 μm to 30 μm, and more preferably 6 μm to 15 μm. Further, a shape can be imparted to the light shielding pattern in order to suppress bubble mixing due to a step between the light shielding pattern and the display portion and visual recognition of the boundary portion.

<Method for producing circularly polarizing plate>
Taking the circularly polarizing plate 100 shown in FIG. 1A as an example, a method of manufacturing a circularly polarizing plate will be described. The circularly polarizing plate 100 can be manufactured by laminating the polarizing plate 1 and the retardation film 2 via the pressure-sensitive adhesive layer 13.

  The polarizing plate 1 can be manufactured by laminating the polarizer 10 and the protective film 11 via adhesive layers. The polarizing plate may be manufactured by preparing long members and bonding the respective members with roll-to-roll, and then cutting them into a predetermined shape, or cutting each member into a predetermined shape. You may paste together later. After bonding the protective film 11 to the polarizer 10, a heating process or a humidity control process may be provided. An appropriate sacrificial film can be bonded to the surface opposite to the surface on which the protective film 11 of the polarizer 10 is bonded.

  As described above, the retardation film 20 preferably has a retardation layer composed of a liquid crystal cured film obtained by polymerizing and curing a polymerizable liquid crystal compound. Here, the production of a retardation film having a layer made of a liquid crystal cured film will be simply described. The retardation film 20 can be manufactured as follows, for example. An alignment film is formed on the substrate, and a coating liquid containing a polymerizable liquid crystal compound is applied on the alignment film. In the state in which the polymerizable liquid crystal compound is aligned, the active energy ray is irradiated to cure the polymerizable liquid crystal compound. The pressure-sensitive adhesive layer 14 formed on the release film is laminated on the layer where the polymerizable liquid crystal compound is cured. Next, the substrate and / or the alignment film are peeled off. Next, the pressure-sensitive adhesive layer 13 formed on the release film is laminated on the protective film 12. The retardation film 20 may be manufactured by preparing long members and bonding the respective members together in a roll-to-roll manner, and then cutting them into a predetermined shape. After cutting, they may be bonded together.

  And the circularly-polarizing plate 100 can be produced by peeling the peeling film laminated | stacked on the adhesive layer 13, and bonding the retardation film 20 and the polarizing plate 1 through the adhesive layer 13. FIG. .

<Application>
The circularly polarizing plate can be used for various display devices. A display device is a device having a display element and includes a light-emitting element or a light-emitting device as a light-emitting source. Examples of the display device include a liquid crystal display device, an organic EL display device, an inorganic electroluminescence (hereinafter also referred to as inorganic EL) display device, an electron emission display device (for example, a field emission display device (also referred to as FED), and a surface field emission display. Device (also referred to as SED)), electronic paper (display device using electronic ink or electrophoretic elements, plasma display device, projection display device (eg, grating light valve (also referred to as GLV) display device), digital micromirror device (DMD) Display device), piezoelectric ceramic display, etc. The liquid crystal display device includes any of a transmissive liquid crystal display device, a transflective liquid crystal display device, etc. These display devices are two-dimensional images. May be a display device that displays a 3D display device that displays a three-dimensional image What it may be. Yen polarizing plate can be particularly used particularly effectively in the organic EL display device or an inorganic EL display device.

  2A and 2B, in the organic EL display devices 104 and 105, a circularly polarizing plate is laminated on the organic EL display element 3 through an adhesive layer 14 laminated on the retardation film 20. It has a layer structure. Hereinafter, this organic EL may be referred to as “OLED”.

  EXAMPLES Hereinafter, although an Example is shown and this invention is demonstrated further more concretely, this invention is not limited by these examples. In the examples, the parts and% representing the content or amount used are based on weight unless otherwise specified. In addition, each physical property in the following examples was measured by the following method.

(1) Measuring method of film thickness It measured using MH-15M which is a digital micrometer made from Nikon Corporation.

(2) Measuring method of phase difference value It measured using phase difference measuring device KOBRA-WPR (made by Oji Scientific Instruments).

(3) Method of measuring reflected hue The reflected hue (a *, b *) was measured using a spectrocolorimeter (Konica Minolta Japan, Inc., trade name: CM-2600d). The reflected hue is a value when the light source is D65, and was measured by the SCI method (including regular reflected light).

(4) Measuring method of photoelastic coefficient Using a phase difference measuring device KOBRA-WPR (manufactured by Oji Scientific Instruments), both ends of a sample (size 1.5 cm × 6 cm) are sandwiched and stress (0.5 N to 8 N) ), The retardation value (23 ° C./wavelength 550 nm) at the center of the sample was measured and calculated from the slope of the function of stress and retardation value. In this specification, a sample having positive birefringence is described as a positive value, and a sample having negative birefringence is described as a negative value. In addition, the measurement sample of the photoelastic coefficient of a retardation film produced the laminated body which consists of retardation film / adhesive A mentioned later / protective film C mentioned later, the slow axis of this laminated body, and the above-mentioned measurement sample. The sample for measurement was cut out so that the long sides of the were parallel. As the photoelastic coefficient of the retardation film, a value obtained by measuring while applying stress while sandwiching both short sides of the measurement sample was used. In stacking samples, corona treatment was performed on the stacking surface before stacking.

(5) Measuring method of contraction force of polarizer A piece of 2 mm wide by 50 mm long was cut with a super cutter manufactured by Sugano Seiki Co., Ltd. so that the absorption axis direction of the polarizer would be the long axis. The obtained strip-shaped polarizing film was used as a shrinkage force measurement sample. Set the sample for contraction force measurement to a thermomechanical analyzer ("TMA / 6100" manufactured by Hitachi High-Tech Science Co., Ltd.) with a distance between chucks of 10 mm, and place the test piece in a room with a temperature of 20 ° C and a relative humidity of 55%. After standing, the temperature in the sample chamber was raised from 20 ° C. to 80 ° C. over 1 minute, and the temperature in the sample chamber was set to be maintained at 80 ° C. after the temperature rise. After allowing the temperature to rise for 4 hours, the contraction force in the long side direction of the measurement sample was measured in an environment at 80 ° C. In this measurement, the static load was 0 mN, and a SUS probe was used as the jig.

[Production Example 1] Production of polarizing film A polyvinyl alcohol film having a thickness of 20 µm (average polymerization degree of about 2400, saponification degree of 99.9 mol% or more) is uniaxially stretched by about 4 times by dry stretching, and further maintained in a tension state. The sample was immersed in pure water at 40 ° C. for 40 seconds, and then immersed in an aqueous solution having a weight ratio of iodine / potassium iodide / water of 0.052 / 5.7 / 100 at 28 ° C. for 30 seconds for dyeing treatment. went. Thereafter, it was immersed in an aqueous solution having a weight ratio of potassium iodide / boric acid / water of 11.0 / 6.2 / 100 at 70 ° C. for 120 seconds. Subsequently, after washing with pure water at 8 ° C. for 15 seconds, the film is dried at 60 ° C. for 50 seconds and then at 75 ° C. for 20 seconds while being held at a tension of 300 N, and iodine is adsorbed and oriented on the polyvinyl alcohol film. An absorption polarizer having a thickness of 8 μm was obtained. The contraction force of the obtained polarizer was 1.5 N / 2 mm.

[Production Example 2] Production of retardation film 5 parts (weight average molecular weight: 30000) of photo-alignment material having the following structure (Me: represents a methyl group) and 95 parts of cyclopentanone (solvent) are obtained. The resulting mixture was stirred at 80 ° C. for 1 hour to obtain an alignment film forming composition.

1.0 part of a leveling agent (model number F-556; manufactured by DIC) and polymerization are performed on a mixture obtained by mixing the polymerizable liquid crystal compound A and the polymerizable liquid crystal compound B shown below at a mass ratio of 90:10. 6 parts of 2-dimethylamino-2-benzyl-1- (4-morpholinophenyl) butan-1-one (trade name Irgacure 369 (Irg369), manufactured by BASF Japan Ltd.) as an initiator was added.
Further, N-methyl-2-pyrrolidone (NMP) was added so that the solid content concentration was 13%, and the mixture was stirred at 80 ° C. for 1 hour to obtain a composition for forming a liquid crystal cured film.
The polymerizable liquid crystal compound A was produced by the method described in JP 2010-31223 A. The polymerizable liquid crystal compound B was produced according to the method described in JP2009-173893A. Each molecular structure is shown below.

[Polymerizable liquid crystal compound A]

［重合性液晶化合物Ｂ］

[Polymerizable liquid crystal compound B]

[Manufacture of a laminate comprising a base material, an alignment film, and a layer obtained by curing a liquid crystal compound]
After carrying out corona treatment on a 50 μm-thick cycloolefin film (trade name “ZF-14-50” manufactured by Nippon Zeon Co., Ltd.) as a substrate, the alignment film forming composition was applied with a bar coater, Drying at 80 ° C. for 1 minute and using a polarized UV irradiation device (trade name “SPOT CURE SP-9” of USHIO INC.), Integrated light quantity at a wavelength of 313 nm: 100 mJ / cm ² and an axial angle of 45 ° Polarized UV exposure was performed. Subsequently, the alignment liquid crystal cured film forming composition was applied to the alignment film using a bar coater, dried at 120 ° C. for 1 minute, and then a high-pressure mercury lamp [trade name of Ushio Electric Co., Ltd .: “Unicure VB”. -15201BY-A "] is used to form a layer in which the liquid crystal compound is cured by irradiating ultraviolet rays (in a nitrogen atmosphere, integrated light quantity at a wavelength of 365 nm: 500 mJ / cm ² ). A laminate comprising a layer in which the compound was cured was obtained.

The in-plane retardation value Re (λ) of the cured layer of the liquid crystal compound produced by the above method is measured after being bonded to glass via an adhesive and then peeling off the cycloolefin-based film as the substrate. did. The measurement results of the phase difference value Re (λ) at each wavelength are Re (450) = 121 nm, Re (550) = 142 nm, Re (650) = 146 nm, Re (450) / Re (550) = 0.85, Re (650) / Re (550) = 1.03. Moreover, the photoelastic coefficient of the obtained retardation film was 53.9 * 10 <^-13> Pa < ^-1 >.

[Preparation of protective film]
Protective film A:
A film in which a hard coat layer having a thickness of 3 μm is formed on a stretched film made of a norbornene-based resin having a thickness of 25 μm [trade name “COP25ST-HC” manufactured by Nippon Paper Industries Co., Ltd.
Protective film B:
A triacetyl cellulose film having a thickness of 20 μm and a positive birefringence (trade name “ZRG20SL” manufactured by FUJIFILM Corporation). The in-plane retardation value Re of the protective film B at a wavelength of 590 nm was 1.1 nm, and the thickness direction retardation value Rth was 1.3 nm. The photoelastic coefficient was 94 × 10 ⁻¹³ Pa ⁻¹ .

[Preparation of Adhesive A]
3 parts by weight of a carboxyl group-modified polyvinyl alcohol [trade name “KL-318” obtained from Kuraray Co., Ltd.] is dissolved in 100 parts by weight of water, and a polyamide epoxy additive [Taoka] which is a water-soluble epoxy resin is dissolved in the aqueous solution. An adhesive A was prepared by adding 1.5 parts by weight of a trade name “Smileze Resin (registered trademark) 650 (30)”, an aqueous solution having a solid content of 30% by weight obtained from Chemical Industries, Ltd.

[Preparation of adhesive B]
After mixing the cation curable components a1 to a3 and the cation polymerization initiator shown below, the cation polymerization initiator and the sensitizer shown below are further mixed, and then defoamed to obtain a photocurable adhesive B. Prepared. In addition, the following compounding quantity is based on solid content.
Cationic curable component a1 (70 parts):
3 ′, 4′-epoxycyclohexylmethyl 3 ′, 4′-epoxycyclohexanecarboxylate (trade name: CEL2021P, manufactured by Daicel Corporation)
Cationic curable component a2 (20 parts):
Neopentyl glycol diglycidyl ether (trade name: EX-211, manufactured by Nagase ChemteX Corporation)
Cationic curable component a3 (10 parts):
2-ethylhexyl glycidyl ether (trade name: EX-121, manufactured by Nagase ChemteX Corporation)
Cationic polymerization initiator (2.25 parts (solid content)):
Product name: 50% propylene carbonate solution / sensitizer (2 parts) of CPI-100 (manufactured by San Apro Co., Ltd.):
1,4-diethoxynaphthalene

[Preparation of adhesive layer A]
Adhesive layer A:
5 μm thick sheet adhesive (“NCF # L2” manufactured by Lintec Corporation)

[Preparation of adhesive layer B]
In the following examples, the weight average molecular weight is 4 columns of “TSKgel XL” manufactured by Tosoh Corporation as a column in the GPC device, and “Shodex GPC KF sold by Showa Denko K.K. -802 ”, 5 in total, connected in series, tetrahydrofuran as eluent, sample concentration 5 mg / mL, sample introduction amount 100 μL, temperature 40 ° C., flow rate 1 mL / min, standard It is the value measured by polystyrene conversion.

[Polymerization Example 1] Production Example of Acrylic Resin (A) as Main Component of Adhesive Composition In a reaction vessel equipped with a cooling pipe, a nitrogen introduction pipe, a thermometer and a stirrer, 81.8 parts of ethyl acetate, (meth) 93.4 parts of n-butyl acrylate as alkyl acrylate (A-1), 5.0 parts of 2-phenoxyethyl acrylate as unsaturated monomer (A-2), unsaturated monomer (A- As 3), 1.0 part of 2-hydroxyethyl acrylate and 0.6 part of acrylic acid were charged, and the internal temperature was raised to 55 ° C. while substituting the air in the reaction vessel with nitrogen gas to eliminate oxygen. Thereafter, a total amount of a solution obtained by dissolving 0.14 part of azobisisobutyronitrile as a polymerization initiator in 10 parts of ethyl acetate was added. One hour after the addition of the polymerization initiator (polymerization initiator solution), ethyl acetate was continuously added into the reaction vessel at an addition rate of 17.3 parts / hour so that the concentration of the acrylic resin product was 35%. While maintaining at an internal temperature of 54 to 56 ° C. for 12 hours, ethyl acetate was finally added to adjust the concentration of the acrylic resin to 20%. The obtained acrylic resin (A) had a polystyrene equivalent weight average molecular weight Mw of 1,650,000 and Mw / Mn of 4.3 by GPC. This is designated as acrylic resin A. The structural unit derived from 2-phenoxyethyl acrylate which is an aromatic ring-containing monomer in acrylic resin A is 5%, and the structural unit derived from 2-hydroxyethyl acrylate which is a hydroxyl group-containing monomer is The structural unit derived from acrylic acid which is 1% and carboxyl group-containing monomer is 0.6%.

<Crosslinking agent>
Coronate L: Obtained from an ethyl acetate solution of trimethylolpropane adduct of tolylene diisocyanate (solid content concentration 75%), Nippon Polyurethane Co., Ltd.
<Silane compounds>
KBM-403: Glycidoxypropyltrimethoxysilane (liquid), obtained from Shin-Etsu Chemical Co., Ltd.

  With respect to 100 parts of the solid content of the acrylic resin A (20% ethyl acetate solution) obtained in Polymerization Example 1, 0.5 part of the silane compound (KBM-403) and 0.5 part of the crosslinking agent (Coronate L) are used. 5 parts were mixed and ethyl acetate was added so that solid content concentration might be 13%, and the adhesive composition was prepared. The obtained pressure-sensitive adhesive composition was dried using an applicator on the release treatment surface of a release-treated polyethylene terephthalate film (trade name “PET 3811”, obtained from Lintec Corporation, called a separator). The film was applied to a thickness of 20 μm and dried at 90 ° C. for 1 minute to prepare a sheet-like pressure-sensitive adhesive B. The gel fraction of the obtained sheet-like pressure-sensitive adhesive B was 83%.

[Preparation of reflector]
A non-lighting panel of an OLED device (Samsung Electronics Co., Ltd., trade name: Galaxy-Tab S8.4) was prepared as a reflector.

[Production Example 2] Production of polarizing plate with single-sided protective film Adhesive A was applied to one surface of the polarizing film obtained in Production Example 1, and protective film A was bonded. At this time, the protective film A was bonded so that the stretching direction was 45 degrees with respect to the absorption axis of the polarizer. Then, it was made to dry and the polarizing plate with a single-sided protective film was obtained.

[Example 1]
A retardation film was bonded to the polarizing plate side with a single-side protective film obtained in Production Example 2 via an adhesive A. Here, the retardation film was laminated so that the slow axis of the retardation film was 45 ° counterclockwise with respect to the absorption axis of the polarizing film. Furthermore, the adhesive B was stuck on the surface opposite to the adhesive layer A side of the retardation film to obtain a circularly polarizing plate with an adhesive. In addition, when bonding these materials, the corona treatment was implemented to the bonding surface of each material.

  The obtained circularly polarizing plate was cut into 140 mm × 70 mm so that the absorption axis of the polarizing film was 45 ° counterclockwise with respect to the long side. The circularly polarizing plate was bonded to non-alkali glass (Corning Corp., Eagle XG) via the acrylic adhesive exposed by peeling the release film.

[Hue evaluation before and after heat test]
The obtained evaluation sample is put into an oven at 80 ° C. for 168 hours, and the evaluation sample is placed on the reflector, and the reflection hue is measured. The measurement points are the points shown in FIG. Nine points shown in FIG. 3 are points in a region 5 mm inside from the end of the circularly polarizing plate, and the short side direction is located at intervals of about 30 mm, and the long side direction is located at intervals of about 65 mm.

As an evaluation of in-plane uniformity, when a * and b * of each measurement point are plotted on color coordinates, the evaluation is performed by the distance between two points that are the farthest away. That is, a value having the largest value of the following formula between two points is taken as an evaluation result.
Δa * b * = [(Δa *) ² + (Δb *) ² ] ^1/2

Δa * and Δb * represent the difference between a * and b * between any two points.

The visibility evaluation was evaluated based on the following four levels A to D. The evaluation results are shown in Table 1.
A: Δa * b * ≦ 0.8 Thermal unevenness is not visible at all.
B: 0.8 <Δa * b * ≦ 1.0 Very slight thermal unevenness is visible.
C: 1.0 <Δa * b * ≦ 1.8 Thermal unevenness is slightly visible.
D: 1.8 <Δa * b * Thermal unevenness is clearly visible.

INDUSTRIAL APPLICABILITY According to the present invention, a circularly polarizing plate having a retardation film, which is useful because it can provide a circularly polarizing plate having a small hue change before and after being placed in a high temperature environment, is useful. In particular, when a circularly polarizing plate having a retardation film containing a layer in which a polymerizable liquid crystal compound is cured is placed in a high temperature environment, in-plane changes in the hue of the circularly polarizing plate, particularly the reflected hue, are likely to occur. Even if it is a circularly polarizing plate having a retardation film including a layer in which a polymerizable liquid crystal compound is cured, a change in hue can be sufficiently suppressed even when placed in a high temperature environment.
Therefore, the circularly polarizing plate of the present invention can be effectively used for display devices, particularly organic EL display devices and inorganic EL display devices.

DESCRIPTION OF SYMBOLS 1 Polarizing plate 20 Retardation film 3 Display panel (display element)
4 Front plate 5 Point 10 Polarizer (polarizing film)
11 Protective films 13, 14, 16 Adhesive layer 15 Adhesive layers 21, 22 Liquid crystal cured film (layer in which polymerizable liquid crystal compound is cured)
100, 101 Circularly polarizing plates 104, 105 Display device

Claims (7)

A circularly polarizing plate having a protective film on one surface of a polarizer and a retardation film on the other surface through an adhesive layer,
The polarizer has a thickness of 15 μm or less,
The retardation film includes a retardation layer having positive birefringence,
The pressure-sensitive adhesive layer is
(A) (A-1) The following formula (I)

(Wherein R ₁ represents a hydrogen atom or a methyl group, and R ₂ represents an alkyl group having 1 to 14 carbon atoms which may be substituted with an alkoxy group having 1 to 10 carbon atoms)
(Meth) acrylic acid alkyl ester represented by 80 to 96% by weight,
(A-2) 3 to 15% by weight of an unsaturated monomer having one olefinic double bond and at least one aromatic ring or aliphatic ring in the molecule, and (A-3) polar functionality 0.1 to 5% by weight of unsaturated monomer having a group
A weight average molecular weight Mw in the range of 1,000,000 to 2,000,000, and a molecular weight distribution represented by a ratio Mw / Mn between the weight average molecular weight Mw and the number average molecular weight Mn. For 100 parts by weight of acrylic resin in the range of 3-7,
(B) A circularly polarizing plate formed from a pressure-sensitive adhesive composition containing 0.01 to 5 parts by weight of a crosslinking agent and having a gel fraction of 60 to 99% by weight. Said (A-2) is the following formula (II)

(Wherein R ₃ represents a hydrogen atom or a methyl group, n is an integer of 1 to 8, and R ₄ represents a hydrogen atom, an alkyl group, an aralkyl group or an aryl group)
The circularly-polarizing plate of Claim 1 which is an aromatic ring containing (meth) acryl compound shown by these.   The (A-3) is an unsaturated monomer having at least one polar functional group selected from the group consisting of a free carboxyl group, a hydroxyl group, an amino group, and an epoxy ring. Circular polarizing plate.   Said (B) is a circularly-polarizing plate in any one of Claims 1-3 containing the crosslinking agent of an isocyanate type compound. The pressure-sensitive adhesive composition is further based on 100 parts by weight of the acrylic resin.
(C) The circularly-polarizing plate in any one of Claims 1-4 containing 0.01 to 1 weight part of silane type compounds.   The circularly polarizing plate according to claim 1, wherein the retardation layer is a layer in which a polymerizable liquid crystal compound is polymerized.   A display device in which the circularly polarizing plate according to claim 1 is laminated on a display element.

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