JP3840209B2 - Manufacturing method of laminated polarizing plate with liner - Google Patents

Description

The present invention relates to a method for producing a laminated polarizing plate including an optical compensation film.

  In a liquid crystal display device, generally, polarizers are arranged on both surfaces of a liquid crystal cell holding liquid crystal. A birefringence layer is further disposed as an optical compensation layer between the liquid crystal cell and the polarizer in order to visually compensate for the phase difference due to the birefringence of the liquid crystal cell in the front direction and the perspective direction.

  In particular, a twisted nematic (TN) type liquid crystal display device has a field of view in which, for example, when viewed from an oblique direction, the contrast is lowered, and the phenomenon that the brightness is reversed in gradation display occurs, so that the display characteristics are lowered. It has angular characteristics. In order to improve this characteristic, as the optical compensation layer, a refractive index (nx, ny, nz) composed of liquid crystal molecules that are cholesterically aligned on the alignment substrate is usually negative uniaxial “nx = ny> nz”. A filling negative birefringent layer is used. The index of refraction (nx, ny, nz) indicates the refractive index in the X-axis, Y-axis, and Z-axis directions of the birefringent layer, respectively, and the X-axis indicates the maximum refractive index in the plane. The Y axis is an axial direction perpendicular to the X axis in the plane, and the Z axis is a thickness direction perpendicular to the X axis and the Y axis. As such an optical compensation layer, for example, an optical compensation layer in which an alignment film is formed on a support and a discotic liquid crystal is tilted and aligned on the alignment film has been reported (for example, Patent Document 1, Patent Reference 2). It has also been reported that a liquid crystalline polymer is applied to an alignment substrate, the liquid crystalline polymer is aligned to form a cholesteric liquid crystal layer, and this is used as an optical compensation layer (for example, Patent Document 3).

  In addition, vertical alignment (VA mode) liquid crystal display devices have been put to practical use. By applying an optical compensator that optically compensates the vertical alignment liquid crystal for viewing angle, a wide viewing angle can be obtained. Methods for realizing the characteristics are known. Specifically, for example, a method of applying two retardation plates having positive birefringence anisotropy and retardation plates having negative birefringence anisotropy has been reported (for example, Patent Documents). 4 and Patent Document 5).

  A laminated polarizing plate in which an optical compensation layer formed of a cholesteric layer as described above and a polarizing plate are integrated is usually the outermost layer so that it can be easily attached to another member such as a liquid crystal cell. The pressure-sensitive adhesive layer is disposed on the surface. And when this laminated polarizing plate is put in the distribution process as a product, the surface of the pressure-sensitive adhesive layer is used for the purpose of preventing contamination of the exposed surface of the pressure-sensitive adhesive layer and maintaining the adhesive force until it is put into practical use. A liner is disposed on the surface.

However, such a laminated polarizing plate with a liner has a problem that, for example, curling occurs due to a dimensional change of the polarizing plate. And when the laminated polarizing plate with a liner in which such curling has occurred is used for various image display devices such as a liquid crystal display device by peeling the liner, the optical compensation layer is changed along with the dimensional change of the polarizing plate. There was a problem that optical distortion streaks due to deformation were observed.
Japanese Patent No. 2692035 Japanese Patent No. 2802719 Japanese Patent No. 2660601 JP-A-10-153802 JP-A-11-95208

Accordingly, an object of the present invention is to provide a method for producing a laminated polarizing plate with a liner having an optical compensation layer in which the occurrence of curling is suppressed even in the distribution process.

In order to achieve the above object, a method for producing a laminated polarizing plate with a liner according to the present invention comprises a laminated polarizing plate comprising an optical compensation layer laminated on at least one surface of a polarizing plate and a peelable liner. A method for producing a polarizing plate, comprising a step of laminating a liner on at least one surface of the laminated polarizing plate,
In the step, in a state where a constant tension is applied in the longitudinal direction or the width direction of the liner, the liner is laminated on the surface of the laminated polarizing plate via an adhesive layer,
When the shrinkage rate X of the liner in the laminated polarizing plate with liner is represented by the following formula (I), and the shrinkage rate Y of the laminated polarizing plate in the laminated polarizing plate with the liner is represented by the following formula (II), The shrinkage rate X and the shrinkage rate Y satisfy the condition of the following formula (III).

Shrinkage rate X (%) = [(Xa−Xb) / Xb] × 100 (I)
Shrinkage rate Y (%) = [(Ya−Yb) / Yb] × 100 (II)
−0.1 ≦ (Shrinkage rate X−Shrinkage rate Y) ≦ 0 (III)
In the formula (I), Xa represents the length of the liner peeled from the laminated polarizing plate with liner, Xb represents the length of the unpeeled liner in the laminated polarizing plate with liner, and in the formula (II) , Ya represents the length of the laminated polarizing plate after peeling the liner from the laminated polarizing plate with liner, and Yb represents the length of the laminated polarizing plate before peeling the liner from the laminated polarizing plate with liner.

Thus, in the manufacturing method of a laminated polarizing plate , by laminating | stacking in the state which applied the fixed tension | tensile_strength to the said nainer, the shrinkage rate of the said liner and the shrinkage rate of the laminated body except the said liner are the said Formula ( A laminated polarizing plate satisfying III) can be produced. In such a laminated polarizing plate, the occurrence of curling caused by the dimensional change of the polarizing plate during the distribution process is also suppressed. Therefore, even when such a laminated polarizing plate is used in various image display devices, the occurrence of so-called optical distortion streaks is suppressed and excellent display characteristics can be obtained. In the case of a conventional laminated polarizing plate with a liner, when the liner side is placed on a desk with a horizontal surface, the vicinity of the center of the laminated polarizing plate with the liner is raised, that is, the liner side is the inside. Therefore, for example, when pasting to a liquid crystal cell, there is a problem that the compatibility with an automatic laminating machine is poor and the pasting efficiency is poor . According to the manufacturing method , the occurrence of such reverse curl can be reduced, so that such a problem can be solved.

In addition, the laminated polarizing plate with a liner obtained by such a production method of the present invention (hereinafter also referred to as a laminated polarizing plate with a liner of the present invention ) is peeled off from the liner and exposed to various optical members by the exposed adhesive layer. For example, not only liquid crystal panels and liquid crystal display devices, but also self-luminous display devices such as electroluminescence (EL) displays, plasma displays (PD) and FEDs (Field Emission Displays) Useful.

The laminated polarizing plate with a liner of the present invention is a method for producing a laminated polarizing plate with a liner comprising a laminated polarizing plate in which an optical compensation layer is laminated on at least one surface of the polarizing plate and a peelable liner, Laminating a liner on at least one surface of the polarizing plate,
In the step, the liner is laminated on the surface of the laminated polarizing plate with an adhesive layer in a state where a constant tension is applied in the longitudinal direction or the width direction of the liner.

  As described above, the present invention is a method for producing a laminated polarizing plate with a liner. The method will be described below.

  First, the polarizing plate and the optical compensation layer are bonded via the pressure-sensitive adhesive or adhesive as described above, and then the pressure-sensitive adhesive layer is formed on the other surface of the optical compensation layer. In addition, the adhesion method of a polarizing plate and an optical compensation layer, and the formation method of the said adhesive layer can be performed by the method as mentioned later.

  Next, the liner is pulled in a longitudinal direction or a width direction, applied with a certain tension, and in a state where the tension is maintained, the liner is brought into contact with the pressure-sensitive adhesive layer on the optical compensation layer, and the optical compensation layer, the liner, By adhering, the laminated polarizing plate with a liner of the present invention is obtained.

  In the laminated polarizing plate with a liner of the present invention, the shrinkage rate X of the liner is represented by the following mathematical formula (I), and the shrinkage rate Y of the laminated polarizing plate is represented by the following mathematical formula (II). The following mathematical formula (III) is satisfied. In the following formula (I), Xa represents the length of the liner peeled from the laminated polarizing plate with liner, Xb represents the length of the unpeeled liner in the laminated polarizing plate with liner, and in the following formula (II) , Ya represents the length of the laminated polarizing plate after peeling the liner from the laminated polarizing plate with liner, and Yb represents the length of the laminated polarizing plate before peeling the liner from the laminated polarizing plate with liner. In the following mathematical formulas (I) and (II), “length” includes both “length in the longitudinal direction” and “length in the width direction perpendicular to the longitudinal direction”, and the length in the longitudinal direction. It is necessary to satisfy the following condition (III) when measuring and also satisfy the following formula (III) when measuring the length in the width direction.

Shrinkage rate X (%) = [(Xa−Xb) / Xb] × 100 (I)
Shrinkage rate Y (%) = [(Ya−Yb) / Yb] × 100 (II)
−0.1 ≦ (Shrinkage rate X−Shrinkage rate Y) ≦ 0 (III)
The laminated polarizing plate with a liner of the present invention is presumed to prevent curling for the following reasons by satisfying the condition of the formula (III).

  In the formula (III), (Shrinkage rate X−Shrinkage rate Y) is −0.1 to 0%, preferably −0.05 to 0%, more preferably −0.03 to 0%. is there. When “shrinkage rate X−shrinkage rate Y” is greater than 0, for example, when the liner side of a laminated polarizing plate with a liner is placed on a desk whose surface is horizontal, the vicinity of the center is lifted, that is, the liner side is the inside. The curled state (also called “reverse curl”). When reverse curling occurs in this way, for example, when a laminated polarizing plate with a liner is pasted on a liquid crystal display device, the compatibility with an automatic laminating machine is poor, so the pasting efficiency is lowered, resulting in lower production efficiency. Problem arises. On the other hand, if it is less than −0.1%, it is not reverse curled but is in a state where both ends of the laminated polarizing plate with liner are lifted, that is, a state in which the polarizing plate side is curled (also referred to as “normal curl”). However, since it becomes a large positive curl exceeding the allowable range, similarly, there is a problem that the compatibility with the automatic laminating machine is poor and the production efficiency is lowered.

  In the present invention, the optical compensation layer is preferably a cholesteric layer in which constituent molecules have a cholesteric structure and are oriented.

  The cholesteric layer is a layer having a pseudo-layer structure called a so-called planar structure or Grandian structure in which the constituent molecules of the layer have a helical structure and the helical axis is oriented substantially perpendicular to the plane direction. it can. Further, in the present invention, “the constituent molecules have a cholesteric structure” is not limited to the case where the liquid crystal compound is in a cholesteric liquid crystal phase, and is not a liquid crystal phase, but a non-liquid crystal compound is Also included are those that are aligned in a twisted state, such as the cholesteric liquid crystal phase. Accordingly, examples of constituent molecules of the cholesteric layer include liquid crystalline polymers and non-liquid crystalline polymers as described later.

  The cholesteric layer preferably has a refractive index (nx, ny, nz) in the three axial directions as described above, for example, nx≈ny> nz. An optical compensation plate including an optical compensation layer having such optical characteristics can be used as a so-called negative C-Plate retardation plate.

  The cholesteric layer has a selective reflection wavelength band of, for example, a range of 100 nm to 320 nm, and an upper limit thereof is preferably 300 nm or less. On the other hand, the lower limit is preferably 150 nm or more. If the selective reflection wavelength is in such a range, for example, coloring of the cholesteric layer and light leakage in a crossed Nicol state can be sufficiently avoided. Therefore, when the optical compensator of the present invention is used for various image display devices. In addition, even more excellent display characteristics can be provided in both the front direction and the perspective direction.

  For example, when the cholesteric layer is formed using a liquid crystal monomer as described later, the center wavelength of the selective reflection wavelength band λ (nm) can be expressed by the following formula.

λ = n · P
In the above formula, n represents the average refractive index of the liquid crystal monomer, and P represents the helical pitch (μm) of the cholesteric layer. The average refractive index n is represented by “(no + ne) / 2” and is usually in the range of 1.45 to 1.65, no is normal light refraction of the liquid crystal monomer, and ne is the liquid crystal monomer. Shows the extraordinary refractive index.

  The cholesteric layer preferably contains a chiral agent. The chiral agent in the present invention is, for example, a compound having a function of orienting constituent molecules such as a liquid crystal monomer and a liquid crystalline polymer described later so as to have a cholesteric structure.

  The kind of the chiral agent is not particularly limited as long as the constituent molecules of the cholesteric layer can be oriented in the cholesteric structure as described above. For example, the chiral agent described later is preferable.

Among these chiral agents, the twisting force is preferably 1 × 10 ⁻⁶ nm ⁻¹ · (wt%) ⁻¹ or more, more preferably 1 × 10 ⁻⁵ nm ⁻¹ · (wt%). ⁻¹ or more, more preferably in the range of 1 × 10 ⁻⁵ to 1 × 10 ⁻² nm ⁻¹ · (wt%) ⁻¹ , particularly preferably 1 × 10 ⁻⁴ to 1 × 10 ⁻³ nm. ^-1 · (wt%) ^-1 . If such a chiral agent having a twisting force is used, for example, the helical pitch of the formed cholesteric layer can be controlled within the range described later, and thereby the selective reflection wavelength band can be sufficiently controlled within the range. Is possible.

  The torsional force generally indicates the ability to twist a liquid crystal material such as a liquid crystal monomer and a liquid crystalline polymer as will be described later and to align it in a spiral manner, and can be expressed by the following formula.

Torsional force = 1 / [Cholesteric pitch (nm) × Chiral agent weight ratio (wt%)]
In the above formula, the weight ratio of the chiral agent means, for example, a ratio (weight ratio) of the chiral agent in a mixture containing a liquid crystal monomer or a liquid crystalline polymer and a chiral agent, and is represented by the following formula.

Chiral agent weight ratio (wt%) = [X / (X + Y)] × 100
X: Chiral agent weight Y: Liquid crystal monomer weight or liquid crystal polymer weight The helical pitch in the cholesteric layer is, for example, 0.25 μm or less, preferably in the range of 0.01 to 0.25 μm, and more preferably. Is in the range of 0.03 to 0.20 μm, particularly preferably in the range of 0.05 to 0.15 μm. If the helical pitch is 0.01 μm or more, for example, sufficient orientation is obtained, and if it is 0.25 μm or less, for example, the optical rotation on the short wavelength side of visible light can be sufficiently suppressed. In the case of using in, light leakage etc. can be avoided sufficiently. If a chiral agent having a twisting force as described above is used, the helical pitch of the formed cholesteric layer can be controlled within the above range.

  The cholesteric layer preferably has a single hue b value of, for example, 1.2 or less, more preferably 1.1 or less, and particularly preferably 1.0 or less. A cholesteric layer in such a range, for example, has very little coloration and exhibits extremely excellent optical characteristics. The single hue b value in such a range can be achieved, for example, by controlling the selective reflection wavelength band in the above-described range.

  The single hue b value is determined by Hunter Lab color system (Hunter, RS: J. Opt. Soc. Amer., 38, 661 (A), 1094 (A) (1948); J. Opt. Soc. Amer. , 48, 985 (1958)). Specifically, for example, according to JIS K 7105 5.3, tristimulus values (X, Y, Z) of a sample are measured using a spectrophotometer or a photoelectric colorimeter, and these values are used as color differences in Lab space. A simple hue b value can be calculated by substituting it into the following Hunter formula as a formula. For this measurement, a C light source is usually used. For example, according to an integrating sphere type spectral transmittance measuring device (trade name DOT-3C; manufactured by Murakami Color Research Laboratory), the single hue b value can be measured together with the transmittance.

Single unit hue b = 7.0 × (Y−0.847Z) / Y1 / 2
Specific examples of the constituent molecules of the cholesteric layer include a non-liquid crystalline polymer. The non-liquid crystalline polymer is preferably a polymer obtained by polymerizing or crosslinking a liquid crystal monomer having a cholesteric structure. In such a configuration, as will be described later, since the monomer exhibits liquid crystallinity, the cholesteric structure can be aligned and the alignment can be fixed by polymerizing the monomers. is there. For this reason, although the liquid crystal monomer is used, the polymerized polymer becomes non-liquid crystalline due to the fixing. In order to make the liquid crystal monomer have a cholesteric structure, for example, when a chiral agent as described below is used, the liquid crystal monomer and the chiral agent are non-liquid crystalline polymers that are polymerized and crosslinked.

  As a constituent molecule of the cholesteric layer, such a non-liquid crystalline polymer is preferable for the following reasons. A cholesteric layer formed from such a non-liquid crystalline polymer has a cholesteric structure like a cholesteric liquid crystal phase, but is not composed of liquid crystal molecules as described above. The liquid crystal phase, the glass phase, and the crystal phase are not changed due to. Therefore, since the cholesteric structure is an optical compensation layer that is not affected by temperature changes and has excellent stability, the optical compensation plate of the present invention can be said to be useful as a retardation film for optical compensation, for example.

  As the liquid crystal monomer, a monomer represented by the following chemical formula (1) is preferable. Such a liquid crystal monomer is generally a nematic liquid crystal monomer. However, in the present invention, for example, a twist is imparted by the chiral agent, and finally a cholesteric structure is obtained. Further, in the cholesteric layer, the monomers need to be polymerized or cross-linked in order to fix the orientation. Therefore, the monomer preferably contains at least one of a polymerizable monomer and a cross-linkable monomer.

  When the liquid crystal monomer is used, the cholesteric layer preferably further contains at least one of a polymerizing agent and a crosslinking agent. For example, substances such as an ultraviolet curing agent, a photocuring agent, and a thermosetting agent can be used. .

  The ratio of the liquid crystal monomer in the cholesteric layer is preferably, for example, in the range of 75 to 95% by weight, and more preferably in the range of 80 to 90% by weight. The ratio of the chiral agent to the liquid crystal monomer is preferably in the range of 5 to 23% by weight, and more preferably in the range of 10 to 20% by weight. The ratio of the crosslinking agent or the polymerization agent to the liquid crystal monomer is preferably in the range of 0.1 to 10% by weight, more preferably in the range of 0.5 to 8% by weight, and particularly preferably 1 to 1% by weight. It is in the range of 5% by weight.

  In addition to the non-liquid crystalline polymer, examples of the constituent molecules of the cholesteric layer include a liquid crystalline polymer, and the liquid crystalline polymer is a cholesteric layer having a configuration in which a cholesteric structure is aligned. May be. Examples of the liquid crystalline polymer include various liquid crystalline polymers disclosed in Japanese Patent No. 2660601.

  The thickness of the optical compensation layer is not particularly limited, but is, for example, in the range of 3 to 200 μm, preferably 10 to 180 μm, and particularly preferably 30 to 150 μm.

  The type of the optical compensation layer is not particularly limited, but a cholesteric layer having a non-liquid crystalline polymer as a constituent molecule as described above can be prepared, for example, as follows.

For example, a step of spreading a coating liquid containing a liquid crystal monomer, the chiral agent, and at least one of a polymerization agent and a crosslinking agent on an alignment substrate to form a spread layer,
In order to form the cholesteric layer of the non-liquid crystalline polymer by fixing the alignment of the liquid crystal monomer and heat-treating the spreading layer so that the liquid crystal monomer has an orientation having a cholesteric structure. It can be formed by a production method including a step of subjecting the spreading layer to at least one of a polymerization treatment and a crosslinking treatment.

  First, a coating liquid containing the liquid crystal monomer, the chiral agent, and at least one of the crosslinking agent and the polymerization agent is prepared.

  As the liquid crystal monomer, for example, a nematic liquid crystal monomer is preferable, and specific examples include a monomer represented by the following formula (1). One kind of these liquid crystal monomers may be used, or two or more kinds may be used in combination.

前記式（１）において、Ａ¹およびＡ²は、それぞれ重合性基を表し、同一でも異なっていてもよい。また、Ａ¹およびＡ²はいずれか一方が水素であってもよい。Ｘは、それぞれ単結合、−Ｏ−、−Ｓ−、−Ｃ＝Ｎ−、−Ｏ−ＣＯ−、−ＣＯ−Ｏ−、−Ｏ−ＣＯ−Ｏ−、−ＣＯ−ＮＲ−、−ＮＲ−ＣＯ−、−ＮＲ−、−Ｏ−ＣＯ−ＮＲ−、−ＮＲ−ＣＯ−Ｏ−、−ＣＨ₂−Ｏ−または−ＮＲ−ＣＯ−ＮＲを表し、前記ＸにおいてＲは、ＨまたはＣ₁〜Ｃ₄アルキル基を表し、Ｍはメソーゲン基を表す。

In the formula (1), A ¹ and A ² each represent a polymerizable group, and may be the same or different. One of A ¹ and A ² may be hydrogen. X represents a single bond, —O—, —S—, —C═N—, —O—CO—, —CO—O—, —O—CO—O—, —CO—NR—, —NR—, respectively. CO—, —NR—, —O—CO—NR—, —NR—CO—O—, —CH ₂ —O— or —NR—CO—NR, wherein R is H or C _1- C ₄ represents an alkyl group, and M represents a mesogen group.

  In the formula (1), Xs may be the same or different, but are preferably the same.

Among the monomers represented by the formula (1), each A ² is preferably located in the ortho position with respect to A ¹ .

A ¹ and A ² are each independently represented by the following formula Z-X- (Sp) n (2)
And A ¹ and A ² are preferably the same group.

In the above formula (2), Z represents a crosslinkable group, X is the same as in the above formula (1), and Sp is a linear or branched alkyl group having 1 to 30 C atoms. N represents 0 or 1. Carbon chain in the Sp, for example, oxygen in ether functional group, sulfur in a thioether functional group, may be interrupted by such alkylimino group nonadjacent imino or C ₁ -C _4.

  In the formula (2), Z is preferably any one of atomic groups represented by the following formula. In the following formula, examples of R include a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, an i-butyl group, and a t-butyl group.

また、前記式（２）において、Ｓｐは、下記式で表される原子団のいずれかであることが好ましく、下記式において、ｍは１〜３、ｐは１〜１２であることが好ましい。

In the formula (2), Sp is preferably any one of the atomic groups represented by the following formula. In the following formula, m is preferably 1 to 3, and p is preferably 1 to 12.

前記式（１）において、Ｍは、下記式（３）で表されることが好ましく、下記（３）において、Ｘは、前記式（１）におけるＸと同様である。Ｑは、例えば、置換または未置換のアルキレン基もしくは芳香族炭化水素原子団を表し、また、例えば、置換または未置換の直鎖もしくは分枝鎖Ｃ₁〜Ｃ₁₂アルキレン基等であってもよい。

In the formula (1), M is preferably represented by the following formula (3). In the following (3), X is the same as X in the formula (1). Q represents, for example, a substituted or unsubstituted alkylene group or an aromatic hydrocarbon group, and may be, for example, a substituted or unsubstituted linear or branched C ₁ -C ₁₂ alkylene group. .

前記Ｑが、前記芳香族炭化水素原子団の場合、例えば、下記式に表されるような原子団や、それらの置換類似体が好ましい。

When Q is the aromatic hydrocarbon atomic group, for example, an atomic group represented by the following formula or a substituted analog thereof is preferable.

前記式に表される芳香族炭化水素原子団の置換類似体としては、例えば、芳香族環１個につき１〜４個の置換基を有してもよく、また、芳香族環または基１個につき、１または２個の置換基を有してもよい。前記置換基は、それぞれ同一であっても異なっていてもよい。前記置換基としては、例えば、Ｃ₁〜Ｃ₄アルキル基、ニトロ基、Ｆ、Ｃｌ、Ｂｒ、Ｉ等のハロゲン、フェニル基、Ｃ₁〜Ｃ₄アルコキシ基等があげられる。

The substituted analog of the aromatic hydrocarbon group represented by the above formula may have, for example, 1 to 4 substituents per aromatic ring, and may include one aromatic ring or one group. Each may have 1 or 2 substituents. The substituents may be the same or different. Examples of the substituent include C ₁ -C ₄ alkyl groups, nitro groups, halogens such as F, Cl, Br, and I, phenyl groups, C ₁ -C ₄ alkoxy groups, and the like.

  Specific examples of the liquid crystal monomer include monomers represented by the following formulas (4) to (19).

前記液晶モノマーが液晶性を示す温度範囲は、その種類に応じて異なるが、例えば、４０〜１２０℃の範囲であることが好ましく、より好ましくは５０〜１００℃の範囲であり、特に好ましくは６０〜９０℃の範囲である。

The temperature range in which the liquid crystal monomer exhibits liquid crystallinity varies depending on the type, but is preferably in the range of 40 to 120 ° C., more preferably in the range of 50 to 100 ° C., and particularly preferably 60. It is the range of -90 degreeC.

  The chiral agent is not particularly limited, as described above, for example, as long as the liquid crystal monomer is twisted to be aligned so as to have a cholesteric structure, but is preferably a polymerizable chiral agent. The above can be used. One kind of these chiral agents may be used, or two or more kinds thereof may be used in combination.

  Specifically, as the polymerizable chiral agent, for example, chiral compounds represented by the following general formulas (20) to (23) can be used.

^{(Z-X 5) nCh (} 20)
^{(Z-X 2 -Sp-X} 5) n Ch (21)
(P ¹ −X ⁵ ) _n Ch (22)
^{(Z-X 2 -Sp-X} 3 -M-X 4) n Ch (23)
In each of the above formulas, Z is the same as in the above formula (2), Sp is the same as in the above formula (2), and X ² , X ³ and X ⁴ are each independently a chemical single bond , -O-, -S-, -O-CO-, -CO-O-, -O-CO-O-, -CO-NR-, -NR-CO-, -O-CO-NR-,- NR-CO-O -, - NR-CO-NR- the stands, the R represents H, a C ₁ -C ₄ alkyl group. X ⁵ represents a chemical single bond, —O—, —S—, —O—CO—, —CO—O—, —O—CO—O—, —CO—NR—, —NR—CO—. , —O—CO—NR—, —NR—CO—O—, —NR—CO—NR, —CH ₂ O—, —O—CH ₂ —, —CH═N—, —N═CH— or — N≡N— is represented. R is the same manner as described above represents H, C ₁ -C ₄ alkyl group. M represents a mesogen group as described above, and P ¹ represents hydrogen, a C _{1 to} C ₃₀ alkyl group substituted with _{1 to} 3 C _{1 to} C ₆ alkyl groups, a C ₁ to ₃₀ acyl group, or C 1 It represents ₃ -C ₈ cycloalkyl radical, n is an integer from 1 to 6. Ch represents an n-valent chiral group. In the formula (23), at least one of X ³ and X ⁴ is —O—CO—O—, —O—CO—NR—, —NR—CO—O—, or —NR—CO—NR—. It is preferable that In the formula (22), when P ¹ is an alkyl group, an acyl group or a cycloalkyl group, for example, the carbon chain is oxygen in the ether functional group, sulfur in the thioether functional group, non-adjacent imino group or it may be interrupted by C ₁ -C ₄ alkylimino groups.

  Examples of the chiral group of Ch include an atomic group represented by the following formula.

前記原子団において、Ｌは、Ｃ₁〜Ｃ₄アルキル基、Ｃ₁〜Ｃ₄アルコキシ基、ハロゲン、ＣＯＯＲ、ＯＣＯＲ、ＣＯＮＨＲまたはＮＨＣＯＲであって、前記ＲはＣ₁〜Ｃ₄アルキル基を表す。なお、前記式に表した原子団における末端は、隣接する基との結合手を示す。

In the atomic group, L is, C ₁ -C ₄ alkyl group, C ₁ -C ₄ alkoxy group, a halogen, COOR, OCOR, a CONHR or NHCOR, wherein R represents C ₁ -C ₄ alkyl group. In addition, the terminal in the atomic group represented by the above formula represents a bond with an adjacent group.

  Among the atomic groups, an atomic group represented by the following formula is particularly preferable.

また、前記（２１）または（２３）で表されるカイラル化合物は、例えば、ｎが２、ＺがＨ₂Ｃ＝ＣＨ−を表し、Ｃｈが下記式で表される原子団であることが好ましい。

In addition, the chiral compound represented by the above (21) or (23) is preferably an atomic group in which, for example, n is 2, Z represents H ₂ C═CH—, and Ch is represented by the following formula. .

前記カイラル化合物の具体例としては、例えば、下記式（２４）〜（４４）で表される化合物があげられる。なお、これらのカイラル化合物は、ねじり力が１×１０^-6ｎｍ^-1（ｗｔ％）^-1以上である。

Specific examples of the chiral compound include compounds represented by the following formulas (24) to (44). These chiral compounds have a twisting force of 1 × 10 ⁻⁶ nm ⁻¹ (wt%) ⁻¹ or more.

前述のようなカイラル化合物の他にも、例えば、ＲＥ−Ａ４３４２２８０号およびドイツ国特許出願１９５２０６６０．６号および１９５２０７０４．１号にあげられるカイラル化合物が好ましく使用できる。

In addition to the above-mentioned chiral compounds, for example, chiral compounds listed in RE-A 4342280 and German Patent Applications 19520660.6 and 195207041 can be preferably used.

  Although it does not restrict | limit especially as said polymerizer and a crosslinking agent, For example, the following can be used. Examples of the polymerization agent include benzoyl peroxide (BPO) and azobisisobutyronitrile (AIBN). Examples of the crosslinking agent include isocyanate crosslinking agents, epoxy crosslinking agents, and metal chelate crosslinking. An agent can be used. These may be either one of them, or two or more of them may be used in combination.

  The coating liquid can be prepared, for example, by dissolving and dispersing the liquid crystal monomer and the like in an appropriate solvent. Examples of the solvent include, but are not limited to, for example, halogenated hydrocarbons such as chloroform, dichloromethane, carbon tetrachloride, dichloroethane, tetrachloroethane, methylene chloride, trichloroethylene, tetrachloroethylene, chlorobenzene, and orthodichlorobenzene, phenol, p- Phenols such as chlorophenol, o-chlorophenol, m-cresol, o-cresol, p-cresol, aromatic hydrocarbons such as benzene, toluene, xylene, methoxybenzene, 1,2-dimethoxybenzene, acetone, methyl ethyl ketone (MEK), ketone solvents such as methyl isobutyl ketone, cyclohexanone, cyclopentanone, 2-pyrrolidone and N-methyl-2-pyrrolidone, and esters such as ethyl acetate and butyl acetate Solvent, alcohol solvent such as t-butyl alcohol, glycerin, ethylene glycol, triethylene glycol, ethylene glycol monomethyl ether, diethylene glycol dimethyl ether, propylene glycol, dipropylene glycol, 2-methyl-2,4-pentanediol, dimethylformamide Amide solvents such as dimethylacetamide, nitrile solvents such as acetonitrile and butyronitrile, ether solvents such as diethyl ether, dibutyl ether, tetrahydrofuran and dioxane, or carbon disulfide, ethyl cellosolve, butyl cellosolve, etc. Can be used. Among these, toluene, xylene, mesitylene, MEK, methyl isobutyl ketone, cyclohexanone, ethyl cellosolve, butyl cellosolve, ethyl acetate, butyl acetate, propyl acetate, and ethyl acetate cellosolve are preferable. These solvents may be, for example, one kind or a mixture of two or more kinds.

  The addition ratio of the chiral agent is appropriately determined according to, for example, a desired helical pitch and a desired selective reflection wavelength band, and the addition ratio to the liquid crystal monomer is, for example, in the range of 5 to 23% by weight, Preferably it is the range of 10-20 weight%. As described above, by controlling the addition ratio of the liquid crystal monomer and the chiral agent in this manner, the selected wavelength band of the optical film to be formed can be set within the above-described range. If the ratio of the chiral agent to the liquid crystal monomer is 5% by weight or more, for example, it becomes very easy to control the selective reflection wavelength band of the formed optical film to the low wavelength side. In addition, if the ratio is 23% by weight or less, the temperature range in which the liquid crystal monomer is cholesterically aligned, that is, the temperature range in which the liquid crystal monomer is in the liquid crystal phase is widened. Is no longer necessary, and manufacturing becomes extremely easy.

For example, when a chiral agent having the same torsional force is used, the selective reflection wavelength band to be formed is on the lower wavelength side when the addition ratio of the chiral agent to the liquid crystal monomer is larger. For example, when the addition ratio of the chiral agent to the liquid crystal monomer is the same, for example, the selective reflection wavelength band of the formed optical film is on the lower wavelength side when the twisting force of the chiral agent is larger. As a specific example, when the selective reflection wavelength band of the optical film to be formed is set in the range of 200 to 220 nm, for example, a chiral with a twisting force of 5 × 10 ⁻⁴ nm ⁻¹ · (wt%) ⁻¹ . What is necessary is just to mix | blend an agent so that it may become 11 to 13 weight% with respect to a liquid crystal monomer, and when setting the said selective reflection wavelength range to the range of 290-310 nm, for example, twisting force is 5 * 10 < ^-4 >. What is necessary is just to mix | blend the chiral agent of nm <^-1> * (wt%) < ^-1 > so that it may become 7 to 9 weight% with respect to a liquid crystal monomer.

  Further, the combination of the liquid crystal monomer and the chiral agent is not particularly limited. Specifically, the combination of the monomer agent of the formula (10) and the chiral agent of the formula (38), the formula ( And a combination of the monomer agent of 11) and the chiral agent of the above formula (39).

  The addition ratio of the crosslinking agent or the polymerization agent to the liquid crystal monomer is, for example, in the range of 0.1 to 10% by weight, preferably in the range of 0.5 to 8% by weight, more preferably 1 to 5% by weight. Range. If the ratio of the crosslinking agent or the polymerization agent to the liquid crystal monomer is 0.1% by weight or more, for example, curing of the cholesteric layer is sufficiently easy, and if it is 10% by weight or less, for example, the liquid crystal monomer is Since the temperature range in which the cholesteric alignment is performed, that is, the temperature at which the liquid crystal monomer becomes a liquid crystal phase is in a sufficient range, temperature control in the alignment step described later is further facilitated.

  Moreover, you may mix | blend various additives with the said coating liquid suitably as needed, for example. Examples of the additive include an anti-aging agent, a modifier, a surfactant, a dye, a pigment, a discoloration inhibitor, and an ultraviolet absorber. Any one of these additives may be added, or two or more of them may be used in combination. Specifically, as the anti-aging agent, for example, phenol compounds, amine compounds, organic sulfur compounds, phosphine compounds, etc., and as the modifier, for example, glycols, silicones, alcohols, etc. A well-known thing can be used, respectively. The surfactant is added, for example, to smooth the surface of the optical compensation layer. For example, a silicone-based, acrylic-based, or fluorine-based surfactant can be used, and a silicone-based surfactant is particularly preferable.

  Thus, when a liquid crystal monomer is used, the prepared coating liquid shows the viscosity excellent in workability | operativity, such as coating and expansion | deployment, for example. The viscosity of the coating liquid usually varies depending on the concentration and temperature of the liquid crystal monomer, but when the monomer concentration in the coating liquid is in the range of 5 to 70% by weight, the viscosity is, for example, 0. The range is 2 to 20 mPa · s, preferably 0.5 to 15 mPa · s, and particularly preferably 1 to 10 mPa · s. Specifically, when the monomer concentration in the coating solution is 30% by weight, for example, the range is 2 to 5 mPa · s, and preferably 3 to 4 mPa · s. When the viscosity of the coating liquid is 0.2 mPa · s or more, for example, generation of a liquid flow due to running of the coating liquid can be further prevented, and when the viscosity is 20 mPa · s or less, for example, the surface Smoothness is further improved, thickness unevenness can be further prevented, and coating properties are also excellent. In addition, as said viscosity, although the range in the temperature of 20-30 degreeC was shown, it is not limited to this temperature.

  Next, the coating liquid is applied onto the alignment substrate to form a spread layer.

  The coating liquid may be flow-deployed by a conventionally known method such as a roll coating method, a spin coating method, a wire bar coating method, a dip coating method, an extrusion method, a curtain coating method, a spray coating method, Of these, spin coating and extrusion coating are preferred from the viewpoint of coating efficiency.

The alignment substrate is not particularly limited as long as the liquid crystal monomer can be aligned. For example, a substrate obtained by rubbing the surface of various plastic films or plastic sheets with a rayon cloth or the like can be used. The plastic is not particularly limited. For example, polyolefin such as triacetyl cellulose (TAC), polyethylene, polypropylene, poly (4-methylpentene-1), polyimide, polyimide amide, polyether imide, polyamide, polyether ether. Ketone, polyether ketone, polyketone sulfide, polyethersulfone, polysulfone, polyphenylene sulfide, polyphenylene oxide, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polyacetal, polycarbonate, polyarylate, acrylic resin, polyvinyl alcohol, polypropylene, cellulosic plastic , Epoxy resin, phenol resin, polynorbornene, polyester, Polystyrene, polyvinyl chloride, polyvinylidene chloride, a film or the like formed from the liquid crystalline polymer and the like. In addition, a plastic film or sheet as described above was disposed on the surface of a metal substrate such as aluminum, copper, or iron, a ceramic substrate, or a glass substrate, or a SiO ₂ oblique vapor deposition film was formed on the surface. Things can also be used. Moreover, the laminated body which laminated | stacked the above-mentioned plastic film and sheet | seat on the oriented film etc. which gave the birefringent property etc. which performed the extending | stretching processes, such as uniaxial stretching, can also be used as an oriented substrate. Further, when the substrate itself has birefringence, it is preferable because the rubbing treatment as described above or the lamination of a birefringent film on the surface is unnecessary. As a method for imparting birefringence to the substrate itself as described above, for example, in the formation of the substrate, there is a method of performing casting, extrusion molding, or the like in addition to the stretching treatment.

  Subsequently, the liquid crystal monomer is aligned in a liquid crystal state by subjecting the spread layer to a heat treatment. Since the spread layer contains a chiral agent together with the liquid crystal monomer, the liquid crystal monomer in a liquid crystal phase (liquid crystal state) is aligned in a state where a twist is imparted by the chiral agent. That is, the liquid crystal monomer exhibits a cholesteric structure (helical structure).

  The temperature condition of the heat treatment can be appropriately determined according to, for example, the type of the liquid crystal monomer, specifically the temperature at which the liquid crystal monomer exhibits liquid crystallinity, but is usually in the range of 40 to 120 ° C., preferably It is the range of 50-100 degreeC, More preferably, it is the range of 60-90 degreeC. If the temperature is 40 ° C. or higher, the liquid crystal monomer can usually be sufficiently aligned, and if the temperature is 120 ° C. or lower, for example, selection of various alignment substrates as described above in terms of heat resistance. The nature is also wide.

  Next, the liquid crystal monomer and the chiral agent are polymerized or crosslinked by performing a crosslinking treatment or a polymerization treatment on the spread layer in which the liquid crystal monomer is aligned. As a result, the liquid crystal monomer is polymerized / crosslinked with each other while being aligned with a cholesteric structure, or polymerized / crosslinked with a chiral agent, and the alignment state is fixed. The formed polymer becomes a non-liquid crystalline polymer by fixing the alignment state.

  The polymerization treatment and the crosslinking treatment can be appropriately determined depending on, for example, the kind of the polymerization agent and the crosslinking agent to be used. For example, when a photopolymerization agent or a photocrosslinking agent is used, light irradiation is performed, and when an ultraviolet polymerization agent or an ultraviolet crosslinking agent is used, ultraviolet irradiation is performed.

  As described above, an optical compensation layer formed from a non-liquid crystalline polymer having a cholesteric structure and aligned on the alignment substrate is obtained. This optical compensation layer is non-liquid crystalline because its orientation is fixed as described above. Therefore, the change in temperature does not change, for example, to a liquid crystal phase, a glass phase, or a crystal phase, and an orientation change due to temperature does not occur. Therefore, the optical compensator of the present invention can be used as a high-performance retardation film that is not affected by temperature. Further, if the selective reflection wavelength band is controlled within the above range, the above-described light leakage can be suppressed.

  Further, the optical compensation layer may be used after being peeled off from the alignment substrate, or may be used in a state where it is laminated on the alignment substrate.

  When used as a laminate of the optical compensation layer and the alignment substrate, the alignment substrate is preferably a translucent plastic film. Examples of the plastic film include celluloses such as TAC, polyolefins such as polyethylene, polypropylene, poly (4-methylpentene-1), polyimide, polyamideimide, polyamide, polyetherimide, polyetheretherketone, polyketone sulfide, Polyether sulfone, polysulfone, polyphenylene sulfide, polyphenylene oxide, polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, polyacetal, polycarbonate, polyarylate, acrylic resin, polyvinyl alcohol, polypropylene, cellulose plastic, epoxy resin, phenol resin, polynorbornene , Polyester, polystyrene, polyvinyl chloride, polyvinyl chloride Down, the film may be mentioned that is formed from a liquid crystalline polymer. These films can be optically isotropic or anisotropic. Among these plastic films, from the viewpoint of solvent resistance and heat resistance, for example, each film formed from polypropylene, polyethylene terephthalate, or polyethylene naphthalate is preferable. In addition to this, for example, polymer films described in JP-A-2001-343529 (WO01 / 37007) can be mentioned. Examples of the polymer material include a resin composition containing a thermoplastic resin having a substituted or unsubstituted imide group in the side chain and a thermoplastic resin having a substituted or unsubstituted phenyl group and a nitrile group in the side chain. For example, a resin composition having an alternating copolymer composed of isobutene and N-methylenemaleimide and an acrylonitrile / styrene copolymer can be used. The polymer film may be, for example, an extruded product of the resin composition.

  The translucent alignment substrate as described above may be, for example, a single layer, but may be, for example, a laminate in which different types of polymers are laminated from the viewpoint of improving strength, heat resistance, and adhesion between polymers and liquid crystal monomers. Good.

  The phase difference due to birefringence may not be generated, or for example, the phase difference due to birefringence may be generated for the purpose of eliminating the polarization state of the light reflected by the polarization separation layer. Such elimination of the polarization state is friendly to the suppression of visual color layer change by improving the light utilization efficiency and making it the same as the light source light. As the transparent substrate that generates the phase difference due to the birefringence, for example, stretched films made of various polymers can be used, and the refractive index in the thickness direction may be controlled. The control can be performed, for example, by adhering a polymer film to a heat-shrink film and heating and stretching.

  The thickness of the plastic film is usually 5 μm to 500 μm, preferably 10 to 200 μm, and preferably 15 to 150 μm. If the thickness is 5 μm or more, it has sufficient strength as a substrate, and therefore, for example, it is possible to prevent problems such as breakage during manufacturing.

  As the optical compensation layer, not only such a non-liquid crystalline polymer but also a liquid crystalline polymer may be used as a constituent molecule. In this case, for example, a step of spreading a coating liquid containing the liquid crystalline polymer as described above and the chiral agent on an alignment substrate to form a spread layer, the liquid crystalline polymer has a cholesteric structure. A cholesteric layer having a liquid crystalline polymer as a constituent molecule can be formed by a manufacturing method including a step of subjecting the spread layer to a heat treatment so as to achieve the taken alignment.

  In the laminated polarizing plate with a liner of the present invention, the polarizing plate may be, for example, only a polarizer or may further have a transparent protective layer. The said transparent protective layer may be laminated | stacked only on either one surface of the said polarizer, and may be laminated | stacked on both surfaces. When laminating on both surfaces, for example, the same type of transparent protective layer may be used, or different types of transparent protective layers may be used.

  The polarizer is not particularly limited, and a conventionally known polarizing film can be used. Specifically, for example, a film prepared by adsorbing a dichroic substance such as iodine or a dichroic dye to various films by using a conventionally known method, crosslinking, stretching, and drying are used. it can. Among these, a film that transmits linearly polarized light when natural light is incident is preferable, and a film that is excellent in light transmittance and degree of polarization is preferable. Examples of the various films for adsorbing the dichroic substance include hydrophilic polymer films such as PVA films, partially formalized PVA films, ethylene / vinyl acetate copolymer partially saponified films, and cellulose films. In addition to these, polyene oriented films such as PVA dehydrated products and polyvinyl chloride dehydrochlorinated products can also be used. Among these, PVA film is preferable. Moreover, although the thickness of the said polarizing film is the range of 1-80 micrometers normally, it is not limited to this.

  The transparent protective layer is not particularly limited, and a conventionally known transparent film can be used. For example, a layer having excellent transparency, mechanical strength, thermal stability, moisture barrier property, isotropy, and the like is preferable. Specific examples of the material for such a transparent protective layer include cellulose resins such as triacetyl cellulose, polyester, polycarbonate, polyamide, polyimide, polyethersulfone, polysulfone, polystyrene, and polynorbornene. Transparent resins such as polyethylene, polyolefin, acrylic, and acetate. Further, examples thereof include thermosetting resins such as acrylic, urethane, acrylic urethane, epoxy, and silicone, or ultraviolet curable resins. Among these, a TAC film whose surface is saponified with alkali or the like is preferable from the viewpoint of polarization characteristics and durability.

  Moreover, the polymer film as described in Unexamined-Japanese-Patent No. 2001-343529 (WO01 / 37007) is mention | raise | lifted. Examples of the polymer material include a resin composition containing a thermoplastic resin having a substituted or unsubstituted imide group in the side chain and a thermoplastic resin having a substituted or unsubstituted phenyl group and a nitrile group in the side chain. For example, a resin composition having an alternating copolymer composed of isobutene and N-methylenemaleimide and an acrylonitrile / styrene copolymer can be used. The polymer film may be, for example, an extruded product of the resin composition.

  Moreover, it is preferable that the said transparent protective layer does not have coloring, for example. Specifically, the retardation value (Rth) in the film thickness direction represented by the following formula is preferably in the range of −90 nm to +75 nm, more preferably −80 nm to +60 nm, and particularly preferably −70 nm. It is in the range of ˜ + 45 nm. When the retardation value is in the range of −90 nm to +75 nm, the coloring (optical coloring) of the polarizing plate due to the protective film can be sufficiently eliminated. In the following formula, nx, ny, and nz respectively indicate the refractive indexes in the X-axis, Y-axis, and Z-axis directions of the transparent protective layer, and the X-axis indicates the maximum refractive index in the plane. The Y axis is an axial direction perpendicular to the X axis in the plane, and the Z axis is a thickness direction perpendicular to the X axis and the Y axis. D represents the thickness of the transparent protective layer.

Rth = [[[(nx + ny) / 2] −nz] · d
The transparent protective layer may further have an optical compensation function. As described above, the transparent protective layer having an optical compensation function is intended to prevent coloring or increase the viewing angle for good viewing caused by a change in viewing angle based on a phase difference in a liquid crystal cell, for example. A well-known thing can be used. Specifically, for example, various stretched films obtained by uniaxially or biaxially stretching the above-described transparent resin, alignment films such as liquid crystalline polymers, laminates in which alignment layers such as liquid crystalline polymers are arranged on a transparent substrate, etc. Can be given. Among these, since it is possible to achieve a wide viewing angle with good visibility, the alignment film of the liquid crystalline polymer is preferable, and in particular, an optical compensation layer composed of a tilted alignment layer of a discotic or nematic liquid crystalline polymer, An optically compensated retardation plate supported by the aforementioned triacetylcellulose film or the like is preferable. Examples of such an optical compensation retardation plate include commercially available products such as “WV film” manufactured by Fuji Photo Film Co., Ltd. The optical compensation retardation plate may be one in which optical properties such as retardation are controlled by laminating two or more film supports such as the retardation film and triacetyl cellulose film.

The thickness of the transparent protective layer is not particularly limited, and can be appropriately determined according to, for example, a phase difference or a protective strength, but is usually 5 mm or less, preferably 1 mm or less, more preferably 1 μm to 500 μm, particularly The transparent protective layer is preferably in a range of 5 μm to 150 μm, for example, a method of applying the various transparent resins to the polarizing film, and laminating the transparent resin film, the optical compensation phase difference plate, etc. on the polarizing film. It can form suitably by conventionally well-known methods, such as a method, and can also use a commercial item.

The transparent protective layer may be further subjected to, for example, a hard coat treatment, an antireflection treatment, a treatment for preventing sticking or diffusion, antiglare, and the like. The hard coat treatment is for the purpose of preventing scratches on the surface of the polarizing plate, for example, a treatment for forming a cured film having excellent hardness and slipperiness composed of a curable resin on the surface of the transparent protective layer. It is. As the curable resin, for example, a silicone-based, urethane-based, acrylic-based, or epoxy-based ultraviolet curable resin can be used, and the treatment can be performed by a conventionally known method. The purpose of preventing sticking is to prevent adhesion between adjacent layers. The antireflection treatment is intended to prevent reflection of external light on the surface of the polarizing plate, and can be performed by forming a conventionally known antireflection layer or the like.

  The anti-glare treatment is intended to prevent visual interference of the light transmitted through the polarizing plate due to reflection of external light on the surface of the polarizing plate, for example, on the surface of the transparent protective layer by a conventionally known method, This can be done by forming a fine uneven structure. Examples of a method for forming such a concavo-convex structure include a roughening method by sandblasting or embossing, a method of forming the transparent protective layer by blending transparent fine particles in the transparent resin as described above, and the like. It is done.

  Examples of the transparent fine particles include silica, alumina, titania, zirconia, tin oxide, indium oxide, cadmium oxide, antimony oxide, and the like. In addition, conductive inorganic fine particles, crosslinked or uncrosslinked Organic fine particles composed of polymer particles and the like can also be used. The average particle size of the transparent fine particles is not particularly limited, but is, for example, in the range of 0.5 to 20 μm. The blending ratio of the transparent fine particles is not particularly limited, but is generally preferably in the range of 2 to 70 parts by mass and more preferably in the range of 5 to 50 parts by mass per 100 parts by mass of the transparent resin as described above.

  The antiglare layer containing the transparent fine particles can be used as, for example, the transparent protective layer itself, or may be formed as a coating layer on the surface of the transparent protective layer. Furthermore, the anti-glare layer may also serve as a diffusion layer (visual compensation function or the like) for diffusing the light transmitted through the polarizing plate to expand the viewing angle.

  The antireflection layer, anti-sticking layer, diffusion layer, anti-glare layer, etc. are laminated on the polarizing plate as an optical layer composed of, for example, a sheet provided with these layers, separately from the transparent protective layer. May be.

  In the present invention, the material for forming the liner is not particularly limited, and examples thereof include polyethylene terephthalate (PET).

  The thickness of the liner is, for example, in the range of 10 to 250 μm, preferably 10 to 100 μm, and particularly preferably 20 to 80 μm.

  The material of the pressure-sensitive adhesive layer that bonds the liner and the laminated polarizing plate is not particularly limited, for example, as long as the liner can be bonded and peeled off, but an acrylic resin-based pressure-sensitive adhesive, a rubber-based pressure-sensitive adhesive, Conventionally known adhesives such as vinyl adhesives can be used. The thickness of the pressure-sensitive adhesive layer can be appropriately determined according to, for example, the configuration of the laminated polarizing plate, and is generally 1 to 500 μm, preferably 5 to 50 μm, more preferably 10 to 40 μm. It is particularly preferably 15 to 35 μm.

  Control of the adhesive property of the pressure-sensitive adhesive layer is, for example, the degree of cross-linking depending on the composition and molecular weight of the base polymer forming the pressure-sensitive adhesive layer, the crosslinking method, the content ratio of the crosslinkable functional group, the blending ratio of the crosslinking agent, and the like. It can be suitably carried out by a conventionally known method such as adjusting the molecular weight.

  Further, the method of laminating the polarizing plate and the optical compensation layer, the laminating of the polarizer and the transparent protective layer, etc. is not particularly limited and can be performed by a conventionally known method. In addition to the pressure-sensitive adhesive, an adhesive or the like can also be used. These types can be appropriately determined depending on the material of the polarizing plate, the optical compensation layer, the polarizer, and the transparent protective layer. Although it does not restrict | limit especially as said adhesive agent, For example, polymer adhesives, such as an acrylic type, a vinyl alcohol type, a silicone type, a polyester type, a polyurethane type, a polyether type, a rubber-type adhesive agent etc. can be used. Among these, for example, a material excellent in hygroscopicity and heat resistance is preferable. With such a property, for example, when the laminated polarizing plate with a liner of the present invention is used in a liquid crystal display device or the like, the optical characteristics deteriorate due to foaming or peeling due to moisture absorption, a difference in thermal expansion, or the warp of the liquid crystal cell. It becomes a display device which can prevent such as high quality and excellent durability.

  The pressure-sensitive adhesives and adhesives as described above are hardly peeled off due to, for example, the influence of humidity and heat, and are excellent in light transmittance and degree of polarization. Specifically, when the polarizer is a polyvinyl alcohol-based film, for example, a polyvinyl alcohol-based adhesive is preferable from the viewpoint of stability of the adhesion treatment. For example, these adhesives and pressure-sensitive adhesives may be directly applied to the surface of the polarizer or the transparent protective layer, or the pressure-sensitive adhesive tape or the like may be disposed on the surface. For example, when prepared as an aqueous solution, other additives and catalysts such as acids may be blended as necessary.

  In the present invention, the tension applied to the liner is appropriately determined according to conditions such as the liner material and thickness. For example, it can be set as follows.

Specifically, when the liner is a PET film having a thickness of 10 μm to 250 μm and the long side or the short side is 0.9 m to 1.1 m, the tension is preferably in the range of 150 N to 350 N, more preferably 150 N. It is -250N, Most preferably, it is 180N-220N.

  The laminated polarizing plate with a liner of the present invention comprises a laminated polarizing plate comprising a polarizing plate and an optical compensation layer, and a peelable liner, and the adhesive layer is applied to the optical compensation layer laminated on the polarizing plate. The configuration is not particularly limited as long as the liner is disposed and the mathematical formula (III) is satisfied. Therefore, the laminated polarizing plate may further include other optical members such as a retardation film, a liquid crystal film, a light diffusion film, and a diffraction film. Further, as described above, the polarizing plate may be a polarizer, or a laminate in which a transparent protective layer is laminated on one side or both sides of the polarizer.

  In addition, the laminated polarizing plate with a liner of the present invention and its components (for example, an optical compensation layer) are, for example, salicylic acid ester compounds, benzophenone compounds, benzotriazole compounds, cyanoacrylate compounds, nickel complex compounds, and the like. Those having an ultraviolet absorbing ability by treatment with an ultraviolet absorber or the like may be used.

Next, the present invention will be further described using the following examples and comparative examples. In addition, this invention is not limited only to these Examples.

Example 1
A 1 wt% aqueous solution of polyvinyl alcohol (PVA) (manufactured by Nippon Gosei Kagaku; trade name NH-18) is applied onto a 50 μm thick triacetylcellulose (TAC) film (Fuji Photo Film; trade name T-50SH). And dried at 90 ° C. to form a PVA film having a thickness of about 0.01 μm or less. The surface of this film was rubbed to form an alignment film. On the other hand, the liquid crystal monomer of formula (6) (polymerizable rod-like nematic liquid crystal) and the chiral agent of formula (44) are mixed at a weight ratio of 7: 3, and this mixture becomes 40% by weight. In this manner, a photopolymerization initiator (trade name Irgacure: manufactured by Ciba Specialty Chemicals) was added to the toluene solution so as to be 3% by weight to prepare a coating solution. The coating liquid was applied to the alignment film, and the liquid crystal monomer was aligned by heat treatment at 90 ° C. for 1 minute, and then the liquid crystal monomer was polymerized by UV irradiation to fix the alignment. Then, by removing the TAC film and the PVA film, an optical compensation layer having a thickness of 5 μm was obtained. This optical compensation layer had an in-plane retardation of 1 nm and a thickness direction retardation of 200 nm.

  The obtained optical compensation layer and a commercially available polarizing plate (manufactured by Nitto Denko Corporation; trade name HEG5425DU) are bonded by roll pressure bonding via an acrylic adhesive having a thickness of 10 μm, and the optical compensation layer and the polarizing plate A laminate was prepared (width 1 m).

  The acrylic pressure-sensitive adhesive (thickness 20 μm) was further applied to the surface of the optical compensation layer of the laminate. Then, a liner having a width of 1 m (thickness: 38 μm, trade name: MRA38: manufactured by Mitsubishi Polyester Co., Ltd.) is pulled in the longitudinal direction, a constant tension (200 N) is applied, and the acrylic adhesive is used to maintain the tension. The laminate was bonded to the optical compensation layer side. In this way, a laminated polarizing plate with a liner was produced.

  As a comparative example, a laminated polarizing plate with a liner was prepared in the same manner as in Example 1 except that the liner was adhered to the laminate without applying tension. The following evaluation was performed for the laminated polarizing plate with liner of Example 1 and Comparative Example 1. These results are shown in Table 1 below.

(Observation of curl)
The occurrence of curling in the laminated polarizing plate with a liner immediately after bonding the liner was confirmed. When the liner side of the laminated polarizing plate with the liner is placed on a desk with a horizontal surface, when the vicinity of the center of the laminated polarizing plate with the liner is raised, that is, the curled state so that the liner side is inward. “Reverse curl”, when the both ends of the laminated polarizing plate with a liner were lifted, that is, the state of curling so that the polarizing plate side was inside was evaluated as “normal curl”.

(Shrinkage factor)
About the produced laminated polarizing plate with a liner, the length in the longitudinal direction (Xb ₁ ) and the length in the width direction (Xb ₂ ) of the unpeeled liner in the laminated polarizing plate with a liner, the liner from the laminated polarizing plate with a liner The length (Yb ₁ ) in the longitudinal direction and the length (Yb ₂ ) in the width direction of the laminated polarizing plate before peeling were measured. Next, the liner is peeled from the laminated polarizing plate with the liner, the length (Xa ₁ ) in the longitudinal direction and the length (Xa ₂ ) in the width direction of the peeled liner, and the laminate obtained by peeling the liner. The length of the polarizing plate in the longitudinal direction (Ya ₁ ) and the length in the width direction (Ya ₂ ) were measured. By substituting these measured values into the formula (I) and formula (II), the shrinkage rate X1 in the longitudinal direction of the liner and the shrinkage rate X2 in the width direction, the shrinkage rate Y1 in the longitudinal direction of the laminated polarizing plate, and The shrinkage rate Y2 in the width direction was determined, and the difference between the two shrinkage rates in the longitudinal direction (X ₁ −Y ₁ ) and the difference between the both shrinkage rates in the width direction (X ₂ −Y ₂ ) were calculated.

(Thermal shock test)
The liner was peeled from the produced laminated polarizing plate with liner, and the obtained laminated polarizing plate was adhered to the glass plate with the exposed pressure-sensitive adhesive layer. This laminate was treated at −40 ° C. for 1 hour, and further treated at 80 ° C. for 1 hour. And generation | occurrence | production of the optical distortion streak (linear irregularity) in the said laminated body was confirmed. The results are shown in Table 2 below. In Table 2 below, occurrence of optical distortion streaks is indicated by “x”, and occurrence of non-occurrence is indicated by “◯”.

(Heating test)
The liner was peeled from the produced laminated polarizing plate with liner, and the obtained laminated polarizing plate was adhered to the glass plate with the exposed pressure-sensitive adhesive layer. This laminate was treated at 40 ° C. for a predetermined time (0, 12, 24, 72, 120, 168 hours), and the occurrence of optical distortion streaks was confirmed. The results are shown in Table 2 below. In Table 2 below, occurrence of optical distortion streaks is indicated by “x”, and occurrence of non-occurrence is indicated by “◯”.

As described above, in the case of a laminated polarizing plate with a liner produced by the production method of the present invention, it is possible to prevent the occurrence of curling due to, for example, dimensional change of the polarizing plate during shipment or distribution. Furthermore, when the laminated polarizing plate with a liner of the comparative example that has been reversely curled is peeled off and used as a laminated polarizing plate in a liquid crystal display device, optical distortion streaks are generated by the subsequent heat treatment, and the quality can be maintained. There wasn't. On the other hand, in the case of the laminated polarizing plate with a liner of the present invention that becomes a positive curl, when the liner is peeled and used as a laminated polarizing plate in a liquid crystal display device, optical distortion streaks are also generated by the subsequent heat treatment. Without being able to maintain excellent quality. According to the laminated polarizing plate with a liner of the present invention, it can be said that an excellent quality image display device or the like can be provided.

Claims (12)

A method for producing a laminated polarizing plate with a liner comprising a laminated polarizing plate in which an optical compensation layer is laminated on at least one surface of the polarizing plate and a peelable liner, wherein the liner is provided on at least one surface of the laminated polarizing plate. Laminating steps,
In the step, in a state where a constant tension is applied in the longitudinal direction or the width direction of the liner, the liner is laminated on the surface of the laminated polarizing plate via an adhesive layer,
When the shrinkage rate X of the liner in the laminated polarizing plate with liner is represented by the following formula (I), and the shrinkage rate Y of the laminated polarizing plate in the laminated polarizing plate with the liner is represented by the following formula (II), The manufacturing method, wherein the shrinkage rate X and the shrinkage rate Y satisfy the condition of the following formula (III) .
Shrinkage rate X (%) = [(Xa−Xb) / Xb] × 100 (I)
Shrinkage rate Y (%) = [(Ya−Yb) / Yb] × 100 (II)
−0.1 ≦ (Shrinkage rate X−Shrinkage rate Y) ≦ 0 (III)
In the formula (I), Xa represents the length of the liner peeled from the laminated polarizing plate with liner, Xb represents the length of the unpeeled liner in the laminated polarizing plate with liner, and in the formula (II) , Ya represents the length of the laminated polarizing plate after peeling the liner from the laminated polarizing plate with liner, and Yb represents the length of the laminated polarizing plate before peeling the liner from the laminated polarizing plate with liner. The manufacturing method according to claim 1, wherein the optical compensation layer is a cholesteric layer whose constituent molecules are oriented with a cholesteric structure. The method according to claim 2, wherein the thickness of the cholesteric layer is in the range of 0.5 to 10 µm. 4. The production method according to claim 2, wherein the constituent molecule of the cholesteric layer is a polymer obtained by polymerizing or crosslinking a liquid crystal monomer. The method according to claim 4, wherein the helical pitch of the cholesteric orientation is in the range of 0.01 to 0.25 µm. The manufacturing method according to claim 2 or 3, wherein a constituent molecule of the cholesteric layer is a liquid crystalline polymer, and the liquid crystalline polymer has a cholesteric structure and is aligned. The manufacturing method according to claim 1, wherein the polarizing plate includes a polarizer and a transparent protective layer, and the transparent protective layer is disposed on at least one surface of the polarizer. The manufacturing method according to any one of claims 1 to 7, wherein a material for forming the pressure-sensitive adhesive layer is at least one resin-based pressure-sensitive adhesive selected from the group consisting of an acrylic resin, a rubber-based resin, and a vinyl-based resin. . The manufacturing method as described in any one of Claims 1-8 with which the said optical compensation layer and the polarizing plate are laminated | stacked through the adhesive bond layer or the adhesive layer. The manufacturing method according to claim 9, wherein the material for forming the adhesive layer is at least one curable resin adhesive selected from the group consisting of an epoxy resin, an isocyanate resin, and a polyimide resin. The manufacturing method according to any one of claims 1 to 10, wherein a forming material of the liner is polyethylene terephthalate. 2. The production according to claim 1, wherein when the liner is a PET film having a thickness of 10 μm to 250 μm and the long side or the short side is 0.9 m to 1.1 m, the constant tension is in the range of 150 to 350 N. 3. Method.