JP4413117B2 - Retardation film, polarizing plate, liquid crystal panel, liquid crystal display device and method for producing retardation film - Google Patents

Description

  The present invention relates to a retardation film obtained by aligning and curing a liquid crystalline composition, a polarizing plate using the same, a liquid crystal panel, a liquid crystal display device, and a method for producing a retardation film.

  The retardation film is an optical film used for converting linearly polarized light into circularly polarized light or elliptically polarized light, or conversely converting circularly polarized light or elliptically polarized light into linearly polarized light. Conventionally, stretched films of polymer films such as polycarbonate and polystyrene have been used as the retardation film. However, since the stretched film usually has a thickness of about 40 to 100 μm, for example, when it is used in a liquid crystal display device in which a reduction in thickness is desired, a thinner retardation film is desired.

  Thus, as an alternative to the stretched film, a retardation film using a liquid crystal compound has been attracting attention (see Non-Patent Document 1). Usually, the retardation value of the retardation film is determined by the product of the birefringence and the thickness. However, since the liquid crystalline compound has a large birefringence, an attempt is made to obtain a predetermined retardation value. In some cases, the thickness of the retardation film can be reduced.

  As an example of a retardation film using a liquid crystalline compound, a retardation film is disclosed in which a liquid crystalline composition containing a liquid crystalline compound is applied onto a substrate together with a solvent and cured by irradiating ultraviolet rays. (Patent Document 1). Properties required for the liquid crystal compound include not only excellent transparency of the cured film, but also good solubility in a solvent, uniform alignment, good curability, and the like. Can be mentioned.

However, since the conventional liquid crystalline compound has a birefringence greater than 0.10, the thickness of the film is small when it is intended to produce a retardation film having a small retardation value using such a liquid crystalline compound. Therefore, it was extremely difficult to control the thickness. In addition, a slight variation in thickness is reflected as a large variation in retardation value, and when such a retardation film is used in a liquid crystal display device, display unevenness occurs due to the variation in retardation value. was there. In particular, in recent years, liquid crystal monitors, liquid crystal televisions, and the like have been rapidly increased in size and function, and various optical films used therefor are desired to have further improved characteristics and quality. Under such circumstances, as a retardation film using a liquid crystal compound, development of a retardation film having a small birefringence (for example, 0.10 or less) has been awaited.
JP-A-8-283718 Macromolecules, 28, 3313-3327 (1995).

  The present invention has been made to solve such problems, and its object is to provide a retardation film having a low in-plane birefringence compared to a retardation film using a conventional liquid crystal compound. That is.

As a result of intensive studies to solve the above problems, the present inventors have obtained a retardation film obtained by aligning and curing a liquid crystalline composition containing a polymerizable compound having a specific structure shown below and a liquid crystalline compound. The present invention is completed by finding that the above object can be achieved because the film has excellent transparency and the birefringence in the film surface is significantly lower than that of a conventional retardation film using a liquid crystal compound. It came to. That is, the present invention is as follows.
1. A retardation film obtained by aligning and curing a liquid crystalline composition containing a polymerizable compound represented by the following general formula (1) and a liquid crystalline compound.

（式中、Ｒ１は水素原子又はメチル基、ｎは１〜８の整数、Ｒ２は炭素数１〜８の直鎖状もしくは分岐鎖状のアルキル基、Ｒ３、Ｒ４、Ｒ５及びＲ６はそれぞれ独立して、水素原子、炭素数１〜４の直鎖状又は分岐鎖状のアルキル基、炭素数１〜４のアルコキシ基、ハロゲン原子、ハロゲン化アルキル基、アミノ基、ニトロ基、水酸基又はシアノ基から選ばれる１つの置換基を表す。）
２．前記重合性化合物が、下記式（２）で表される化合物であることを特徴とする上記１に記載の位相差フィルム。

(In the formula, R1 is a hydrogen atom or a methyl group, n is an integer of 1 to 8, R2 is a linear or branched alkyl group having 1 to 8 carbon atoms, and R3, R4, R5 and R6 are independent of each other. A hydrogen atom, a linear or branched alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a halogen atom, a halogenated alkyl group, an amino group, a nitro group, a hydroxyl group, or a cyano group. Represents one selected substituent.)
2. 2. The retardation film as described in 1 above, wherein the polymerizable compound is a compound represented by the following formula (2).

３．前記位相差フィルムの２３℃における波長５９０ｎｍの光で測定した光透過率が８０％以上であることを特徴とする上記１又は２に記載の位相差フィルム。
４．前記位相差フィルムの厚みが、１．１〜１５μｍであることを特徴とする上記１〜３のいずれか一項に記載の位相差フィルム。
５．前記位相差フィルムの２３℃における波長５８９ｎｍの光で測定したフィルム面内の複屈折率が０．０３０〜０．０９５であることを特徴とする上記１〜４のいずれか一項に記載の位相差フィルム。
６．前記位相差フィルムの２３℃における波長５９０ｎｍの光で測定したフィルム面内の位相差値が５０〜８００ｎｍであることを特徴とする上記１〜５のいずれか一項に記載の位相差フィルム。
７．上記１〜６のいずれか一項に記載の位相差フィルムを少なくとも偏光子の片側に配置した偏光板。
８．上記７に記載の偏光板と液晶セルとを含む液晶パネル。
９．前記液晶セルがＴＮモード、ＶＡモード、ＩＰＳモード又はＯＣＢモードである上記８に記載の液晶パネル。
１０．上記８又は上記９に記載の液晶パネルを含む液晶表示装置。
１１． 上記１〜６のいずれか一項に記載の位相差フィルムの製造方法であって、下記一般式（１）で表される重合性化合物と液晶性化合物とを含む液晶性組成物を溶剤と共に基材上に塗工し配向させる工程、および上記液晶性組成物が塗工された基材に放射線照射し上記液晶性組成物を硬化させる工程を含み、上記液晶性組成物１００に対し、上記重合性化合物が１０〜４５（重量比）含まれることを特徴とする位相差フィルムの製造方法。

3. 3. The retardation film as described in 1 or 2 above, wherein the retardation film has a light transmittance of 80% or more measured with light having a wavelength of 590 nm at 23 ° C.
4). The retardation film according to any one of the above 1 to 3, wherein the retardation film has a thickness of 1.1 to 15 µm.
5). The birefringence in the film plane measured with light having a wavelength of 589 nm at 23 ° C. of the retardation film is 0.030 to 0.095. Phase difference film.
6). The retardation film according to any one of 1 to 5 above, wherein an in-plane retardation value measured with light having a wavelength of 590 nm at 23 ° C. of the retardation film is 50 to 800 nm.
7). The polarizing plate which has arrange | positioned the retardation film as described in any one of said 1-6 at least on the one side of a polarizer.
8). 8. A liquid crystal panel comprising the polarizing plate according to 7 and a liquid crystal cell.
9. 9. The liquid crystal panel according to 8 above, wherein the liquid crystal cell is a TN mode, a VA mode, an IPS mode, or an OCB mode.
10. 10. A liquid crystal display device comprising the liquid crystal panel as described in 8 or 9 above.
11. The method for producing a retardation film according to any one of 1 to 6 above, wherein a liquid crystalline composition containing a polymerizable compound represented by the following general formula (1) and a liquid crystalline compound is used together with a solvent. A step of coating and aligning on the material, and a step of irradiating the substrate coated with the liquid crystalline composition with radiation to cure the liquid crystalline composition. 10 to 45 (weight ratio) of a functional compound is contained, A method for producing a retardation film.

（式中、Ｒ１は水素原子又はメチル基、ｎは１〜８の整数、Ｒ２は炭素数１〜８の直鎖状もしくは分岐鎖状のアルキル基、Ｒ３、Ｒ４、Ｒ５及びＲ６はそれぞれ独立して、水素原子、炭素数１〜４の直鎖状又は分岐鎖状のアルキル基、炭素数１〜４のアルコキシ基、ハロゲン原子、ハロゲン化アルキル基、アミノ基、ニトロ基、水酸基又はシアノ基から選ばれる１つの置換基を表す。）

(In the formula, R1 is a hydrogen atom or a methyl group, n is an integer of 1 to 8, R2 is a linear or branched alkyl group having 1 to 8 carbon atoms, and R3, R4, R5 and R6 are independent of each other. A hydrogen atom, a linear or branched alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a halogen atom, a halogenated alkyl group, an amino group, a nitro group, a hydroxyl group, or a cyano group. Represents one selected substituent.)

  The retardation film of the present invention reduces the birefringence in the film plane by using a polymerizable compound having a specific structure together with a liquid crystalline compound, as compared with a retardation film using only a conventionally known liquid crystalline compound. be able to. Moreover, even if it mixes and uses the polymeric compound of a specific structure with a commercially available liquid crystalline composition, it does not phase-separate or crystallize, and can obtain the retardation film which has high transparency. The production method of the present invention can adjust the birefringence index in the film plane depending on the composition ratio of the liquid crystal composition to be used. A thin retardation film with small variations in value can be produced.

  The retardation film of the present invention is obtained by aligning and curing a liquid crystalline composition containing a polymerizable compound represented by the following general formula (1) and a liquid crystalline compound.

本発明に用いられる重合性化合物は、前記一般式（１）で表される特定構造を有するものであり、これらのなかから適宜１種以上を選択して用いることができる。

The polymerizable compound used in the present invention has a specific structure represented by the general formula (1), and one or more of them can be appropriately selected from these.

  In the general formula (1), R1 is a hydrogen atom or a methyl group. R1 is preferably a hydrogen atom.

  N is an integer of 1-8. n is preferably 2 to 4, more preferably 2.

  R2 is a linear or branched alkyl group having 1 to 8 carbon atoms. As R2, those having 2 to 4 carbon atoms are preferably used, and more preferably 3.

  R3, R4, R5 and R6 are each independently a hydrogen atom, a linear or branched alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a halogen atom, or an alkyl halide. One substituent selected from a group, an amino group, a nitro group, a hydroxyl group or a cyano group. R3, R4, R5 and R6 are preferably hydrogen atoms.

  That is, as the polymerizable compound, a compound represented by the following formula (2) is preferably used. If it is the said polymeric compound, since it is excellent in compatibility with a liquid crystalline composition, it is hard to produce phase separation and crystallization, and can obtain a highly transparent retardation film.

本発明に用いられる重合性化合物の製法としては、特に制限はないが、例えば、下記式（３）で表されるクロロアルカノールと、下記式（４）で表される化合物とを、Ｎ，Ｎ−ジメチルホルムアミド等の溶媒中において炭酸カリウム等の塩基の存在下で反応させて下記式（５）で表される化合物を得たのち、該化合物と下記式（６）で表される塩化（メタ）アクリロイルとを、テトラヒドロフラン等の溶媒中においてトリエチルアミン等の塩基の存在下で反応させるといった方法で得ることができる。

Although there is no restriction | limiting in particular as a manufacturing method of the polymeric compound used for this invention, For example, the chloroalkanol represented by following formula (3) and the compound represented by following formula (4) are made into N, N. -After reacting in the presence of a base such as potassium carbonate in a solvent such as dimethylformamide to obtain a compound represented by the following formula (5), the compound and the chloride (meta) represented by the following formula (6) And acryloyl can be obtained by reacting in a solvent such as tetrahydrofuran in the presence of a base such as triethylamine.

本発明において「液晶性組成物」とは液晶相を呈し液晶性を示すものをいう。上記の液晶相としては、ネマチック液晶相、スメクチック液晶相、コレステリック液晶相等が挙げられるが、これらに限定されない。上記液晶相は通常、環状単位等からなるメソゲン基を有する液晶性化合物によって発現される。

In the present invention, the “liquid crystalline composition” means a liquid crystal phase exhibiting liquid crystallinity. Examples of the liquid crystal phase include, but are not limited to, a nematic liquid crystal phase, a smectic liquid crystal phase, and a cholesteric liquid crystal phase. The liquid crystal phase is usually expressed by a liquid crystalline compound having a mesogenic group composed of a cyclic unit or the like.

  Examples of the mesogenic group composed of a cyclic unit of the liquid crystalline compound include, for example, a biphenyl group, a phenylbenzoate group, a phenylcyclohexane group, an azoxybenzene group, an azomethine group, an azobenzene group, a phenylpyrimidine group, a diphenylacetylene group, and a diphenylbenzoate group. , Bicyclohexane group, cyclohexylbenzene group, terphenyl group and the like. In addition, the terminal of these cyclic units may have substituents, such as a cyano group, an alkyl group, an alkoxy group, a halogen group, for example. Especially, as a mesogenic group which consists of a cyclic unit etc., what has a biphenyl group and a phenylbenzoate group is used preferably.

  Specific examples of the liquid crystalline compound include cyanobiphenyls, cyanophenyl esters, benzoic acid esters, azoxys, azomethines, cyclohexanecarboxylic acid phenyl esters, cyanophenylcyclohexanes, cyano-substituted phenylpyrimidines, Examples include alkoxy-substituted phenylpyrimidines, phenyldioxanes, tolanes, alkenylcyclohexylbenzonitriles and the like. As the liquid crystalline compound, benzoic acid esters are preferably used.

  As the liquid crystalline compound, those having at least one polymerizable functional group in a part of the molecule are preferably used. Examples of the polymerizable functional group include an acryloyl group, a methacryloyl group, an epoxy group, and a vinyl ether group. Of these, an acryloyl group and a methacryloyl group are preferably used. Moreover, since the thing which has two or more said polymerizable functional groups can improve durability with the crosslinked structure which arises by a polymerization reaction, it is used preferably. Specific examples of the liquid crystal compound include a product name “Pariocolor LC242” manufactured by BASF.

  The liquid crystalline composition used in the present invention contains the polymerizable compound and the liquid crystalline compound. The liquid crystalline composition may contain an additive. Examples of the additive include various additives such as a heat stabilizer, an ultraviolet degradation inhibitor, a flame retardant, a lubricant, a leveling agent, a lubricant, a plasticizer, and an antistatic agent. The liquid crystalline composition may contain an aligning agent, a chiral compound, or the like for aligning the liquid crystalline compound.

  Moreover, the liquid crystalline composition of the present invention may contain other polymerizable compounds. As the other polymerizable compound, a polyfunctional polymerizable compound having at least two polymerizable functional groups in a part of the molecule is preferably used. The polyfunctional polymerizable functional group is used for the purpose of further improving the heat resistance, solvent resistance, and mechanical strength of the retardation film of the present invention. Moreover, it has the effect of making the birefringence in the film plane of the retardation film of this invention still smaller.

  Examples of the polymerizable functional group of the polyfunctional polymerizable compound used in the present invention include an acryloyl group, a methacryloyl group, an epoxy group, and a vinyl ether group. Of these, an acryloyl group and a methacryloyl group are preferably used. Moreover, as said polyfunctional polymerizable compound, what has 2-4 polymerizable functional groups is preferably used since durability can be improved with the crosslinked structure which arises by a polymerization reaction. More preferably, a trifunctional polymerizable compound having three polymerizable functional groups is used.

  Specific examples of the polyfunctional polymerizable compound include trimethylolpropane triacrylate, pentaerythritol acrylate, trimethylolpropane EO adduct triacrylate, glycerin PO-added triacrylate, trisacryloyloxyethyl phosphate, pentaerythritol tetraacrylate, and the like. Can be mentioned. Among these, trisacryloyloxyethyl phosphate which is a trifunctional polymerizable compound is preferably used.

  The retardation film of the present invention preferably has a light transmittance of 80% or more measured with light having a wavelength of 590 nm at 23 ° C. More preferably, it is 85% or more, and particularly preferably 90% or more.

  In the present invention, “alignment” refers to the operation of arranging the liquid crystalline compounds used in the present invention in a certain state, and “aligned liquid crystalline composition” refers to a liquid crystalline compound contained in the liquid crystalline composition. It means a state in which it is arranged with a certain rule (also referred to as “liquid crystal molecular arrangement”). Although there is no restriction | limiting in particular as said liquid crystal molecular arrangement | sequence, A homogeneous molecular arrangement | sequence, a homeotropic molecular arrangement | sequence, a tilt molecular arrangement | sequence, a hybrid molecular arrangement | sequence, a twist molecular arrangement | sequence, a planar molecular arrangement | sequence, etc. are mentioned.

  The homogeneous molecular arrangement refers to a state in which liquid crystalline compounds are arranged in parallel and in the same direction with respect to the film plane. The homeotropic molecular arrangement refers to a state in which liquid crystalline compounds are arranged perpendicular to the film plane. The tilt molecular arrangement refers to a state in which liquid crystal compounds are inclined at a fixed angle with respect to the film plane and arranged in the same direction. The hybrid molecular arrangement refers to a state in which the liquid crystalline compound has a homogeneous molecular arrangement on the plane of the film and continuously changes to a homeotropic molecular arrangement in the thickness direction. The twist molecular arrangement means a state in which the liquid crystal compound is continuously twisted by 90 ° in parallel to the film plane and in the thickness direction. The planar molecular alignment refers to a state in which the liquid crystalline compound exhibits a cholesteric liquid crystal phase and the helical axis of the liquid crystalline compound is aligned perpendicular to the film plane.

  In the present invention, “curing” refers to an operation in which the liquid crystalline composition used in the present invention is crosslinked by irradiation to change it into a stable state of insoluble, infusible or hardly soluble, and “cured liquid crystalline composition”. The term “product” refers to a cured liquid crystal layer in which the liquid crystalline composition is in a stable state of infusible or insoluble.

  The thickness of the retardation film of the present invention is preferably 1.1 to 15 μm. More preferably. It is 1.2-10 micrometers, Most preferably, it is 1.5-5 micrometers. If it is said range, the thin retardation film with small dispersion | variation in retardation value within a film surface can be obtained. In the present invention, the thickness of the retardation film refers to the thickness of a liquid crystal cured layer obtained by aligning and curing a liquid crystalline composition containing a polymerizable compound.

  The in-plane birefringence of the retardation film of the present invention measured with light having a wavelength of 589 nm at 23 ° C. is preferably 0.030 to 0.095. More preferably, it is 0.050-0.090, Most preferably, it is 0.050-0.070. If it is said range, the thin retardation film with small dispersion | variation in retardation value within a film surface can be obtained.

  In the present invention, the in-plane birefringence of the retardation film is expressed by the formula: nx−ny, where nx and ny are the refractive indices in the slow axis direction and fast axis direction of the film at a wavelength of 589 nm, respectively. Can be sought. The slow axis refers to the direction in which the refractive index in the film plane becomes maximum.

  The in-plane retardation value Re [590] measured with light having a wavelength of 590 nm at 23 ° C. of the retardation film of the present invention is appropriately selected depending on the use of the retardation film, but is usually 50 to 800 nm. Is preferably used. More preferably, it is 50-350 nm. Most preferably, it is 100-300 nm. Re [590] is expressed by the formula: Re [590], where the refractive indexes in the slow axis direction and the fast axis direction of the film at a wavelength of 590 nm are nx and ny, respectively, and d (nm) is the thickness of the film. = (Nx−ny) × d. If it is said range, the thin retardation film with small dispersion | variation in retardation value within a film surface can be obtained.

  When the retardation film of the present invention is used for a λ / 4 plate, Re [590] is preferably from 100 to 170 nm. More preferably, it is 120-160 nm, Most preferably, it is 130-150 nm. When the retardation film of the present invention is used for a λ / 2 plate, Re [590] is preferably from 240 to 300 nm. More preferably, it is 250-290 nm, Most preferably, it is 260-280 nm.

  The retardation value Rth [590] in the thickness direction measured with light having a wavelength of 590 nm at 23 ° C. of the retardation film of the present invention is appropriately selected depending on the use of the retardation film, but is usually 50 to 800 nm. Preferably used. More preferably, it is 50-350 nm. Most preferably, it is 100-300 nm. Rth [590] is expressed by the formula: Rth [590] = (where the refractive index in the slow axis direction and the thickness direction of the film at a wavelength of 590 nm is nx and nz, respectively, and d (nm) is the thickness of the film. nx−nz) × d. If it is said range, the thin retardation film with small dispersion | variation in retardation value within a film surface can be obtained.

  When the retardation film of the present invention is used for a λ / 4 plate, Rth [590] is preferably from 100 to 170 nm. More preferably, it is 120-160 nm, Most preferably, it is 130-150 nm. Moreover, when using the retardation film of this invention for the use of (lambda) / 2 board, that whose Rth [590] is 240-300 nm is used preferably. More preferably, it is 250-290 nm, Most preferably, it is 260-280 nm.

Re [590] and Rth [590] can be obtained using a spectroscopic ellipsometer [manufactured by JASCO Corporation, product name “M-220”]. In-plane retardation value (Re) at a wavelength of 590 nm at 23 ° C., retardation value measured by tilting 40 degrees with the slow axis as the tilt axis (R40), retardation film thickness (d), and retardation film Nx, ny, and nz can be obtained by computer numerical calculation from the following formulas (A) to (D) using the average refractive index (n0), and then Rth can be calculated by formula (D). Here, φ and ny ′ are represented by the following equations (E) and (F), respectively.
Re = (nx−ny) × d (A)
R40 = (nx−ny ′) × d / cos (φ) (B)
(Nx + ny + nz) / 3 = n0 (C)
Rth = (nx−nz) × d (D)
φ = sin ⁻¹ [sin (40 °) / n0] (E)
ny ′ = ny × nz [ny ² × sin ² (φ) + nz ² × cos ² (φ)] ^1/2 (F)

  When the retardation film of the present invention is used for a λ / 4 plate, the Re [590] and Rth [590] variations are preferably those having an average retardation value of ± 4.0% or less. More preferably, it is ± 3.0% or less, and particularly preferably ± 1.5% or less. When the retardation film of the present invention is used for a λ / 2 plate, the Re [590] and Rth [590] variations are preferably those having an average retardation value of ± 2.0% or less. It is done. More preferably, it is ± 1.5% or less, and particularly preferably ± 1.0% or less.

  Next, the manufacturing method of the retardation film of this invention is demonstrated. The method for producing a retardation film of the present invention includes a step of coating and aligning a liquid crystalline composition containing the polymerizable compound and a liquid crystalline compound on a substrate together with a solvent, and the liquid crystalline composition is applied. Including a step of curing the liquid crystalline composition by irradiating the substrate, and the polymerizable compound is contained in an amount of 10 to 45 (weight ratio) with respect to the liquid crystalline composition 100. .

  As a compounding quantity of the said polymeric compound, it is 10-45 (weight ratio) with respect to the said liquid crystalline composition 100, More preferably, it is 20-42 (weight ratio). Especially preferably, it is 30-40 (weight ratio). If it is said range, phase-separation and crystallization will not produce easily in the said liquid crystalline composition, and the retardation film which has high transparency can be obtained.

  The solvent used in the present invention is used to disperse or dissolve the liquid crystalline composition and apply it uniformly on the substrate. In the present invention, the liquid crystal composition dispersed or dissolved in a solvent is also referred to as a “mixed solution”.

  Although there is no restriction | limiting in particular as said solvent, The liquid substance which melt | dissolves the said liquid crystalline composition uniformly and makes it a solution is used preferably. The solvent may be a nonpolar solvent such as benzene or hexane, or a polar solvent such as water or alcohol. The solvent may be an inorganic solvent such as water, alcohols, ketones, ethers, esters, aliphatic and aromatic hydrocarbons, halogenated hydrocarbons, amides, cellosolves. Organic solvents such as

  Specific examples of the solvent include alcohols such as n-butanol, 2-butanol, cyclohexanol, isopropyl alcohol, t-butyl alcohol, glycerin, ethylene glycol, 2-methyl-2,4-pentadiol, phenol, Parachlorophenol etc. are mentioned. Ketones include acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, cyclopentanone, 2-pentanone, 2-hexanone, 2-heptanone, and the like. Examples of ethers include diethyl ether, tetrahydrofuran, dioxane, anisole and the like. Esters include ethyl acetate, butyl acetate, methyl lactate and the like. Aliphatic and aromatic hydrocarbons include n-hexane, benzene, toluene, xylene and the like. Examples of halogenated hydrocarbons include chloroform, dichloromethane, carbon tetrachloride, dichloroethane, trichloroethane, trichloroethylene, tetrachloroethylene, chlorobenzene, and the like. Examples of amides include dimethylformamide and dimethylacetamide. Examples of cellosolves include methyl cellosolve, ethyl cellosolve, and methyl cellosolve. These solvents may be used alone or as a mixture of two or more kinds of solvents selected arbitrarily. In the present invention, the solvent is not limited to those exemplified above.

  In particular, cyclopentanone, cyclohexanone, methyl isobutyl ketone, methyl ethyl ketone, toluene, ethyl acetate, and tetrahydrofuran are preferably used as the solvent. These solvents are preferable because they do not cause erosion that has a practically adverse effect on the substrate and can sufficiently dissolve the above composition.

  The boiling point of the solvent used in the present invention is preferably higher than the liquid crystal phase-isotropic phase transition temperature (Ti) of the liquid crystal composition. As the boiling point of the solvent, those having Ti + 5 ° C. to Ti + 180 ° C. are preferably used. More preferably, it is Ti + 20 degreeC-Ti + 60 degreeC. As a boiling point of the said solvent, it is 55-230 degreeC normally, Preferably 70-150 degreeC is used. By setting the boiling point of the solvent in the above range, uniform coating can be performed. Examples of the solvent having a boiling point in the above range include ketone solvents such as cyclopentanone, cyclohexanone, and methyl isobutyl ketone.

  The total solid content concentration of the mixed solution used in the present invention varies depending on solubility, coating viscosity, wettability on the substrate, thickness after coating, etc., in order to obtain a highly smooth retardation film In the solvent 100, those having a solid content dissolved in 2 to 100 (weight ratio), further 10 to 50 (weight ratio), particularly 20 to 40 (weight ratio) are preferably used.

  Various leveling agents may be added to the mixed solution. The leveling agent is used to improve the wettability of the mixed solution with respect to the substrate. Examples of the leveling agent include various compounds such as silicone-based, fluorine-based, polyether-based, acrylic acid copolymer-based, and titanate-based compounds. Among them, an acrylic acid copolymer type leveling agent is preferably used. Specific examples of the acrylic acid copolymer-based leveling agent include “BYK361” manufactured by Big Chemie.

  The amount of the leveling agent is not particularly limited, but is 0.005 with respect to the liquid crystalline composition 100 in order to enhance smoothness and not disturb the alignment of the liquid crystalline composition used in the present invention. It is preferable to set it to -0.2 (weight ratio). More preferably, it is 0.01-0.1 (weight ratio).

  The substrate used in the present invention is used for uniformly coating the liquid crystalline composition together with a solvent. Although there is no restriction | limiting in particular as said base material, The thing excellent in the smoothness of a base-material surface and the wettability of the mixed solution used for this invention is preferable. Examples of the substrate include glass substrates such as glass plates and quartz substrates, polymer substrates such as films and plastics substrates, metal substrates such as aluminum and iron, inorganic substrates such as ceramic substrates, and silicon wafers. A semiconductor substrate such as is also used. As the substrate, a glass substrate and a polymer substrate are preferably used.

  Examples of the material forming the polymer substrate include thermosetting resins, ultraviolet curable resins, thermoplastic resins, thermoplastic elastomers, and biodegradable plastics. Of these, thermoplastic resins are preferably used. The thermoplastic resin may be an amorphous polymer or a crystalline polymer. Since the amorphous polymer is excellent in transparency, it has an advantage that the retardation film of the present invention can be used as it is for a liquid crystal panel or the like without peeling off from the substrate. On the other hand, since the crystalline polymer is excellent in rigidity, strength, and chemical resistance, it has an advantage that it is excellent in production stability when the retardation film of the present invention is produced.

  The thermoplastic resin used for the polymer substrate includes polyethylene, polypropylene, polynorbornene, polyvinyl chloride, cellulose acetate, polystyrene, ABS resin, AS resin, polymethyl methacrylate, polyvinyl acetate, polyvinylidene chloride, fiber General-purpose plastics such as base resins; general-purpose engineering plastics such as polyamide, polyacetal, polycarbonate, modified polyphenylene ether, polybutylene terephthalate, polyethylene terephthalate; polyphenylene sulfide, polysulfone, polyethersulfone, polyetheretherketone, polyarylate, liquid crystal polymer, Examples thereof include super engineering plastics such as polyamideimide and polytetrafluoroethylene. In addition, the thermoplastic resin can be used after a conventionally known polymer modification. Examples of the polymer modification include modifications such as copolymerization, branching, crosslinking, molecular terminals, and stereoregularity. In addition, in this invention, the thermoplastic resin used for a base material is not limited to what was illustrated above.

  As the base material used in the present invention, a stretched film of the thermoplastic resin is preferably used. In the present invention, the “stretched film” refers to a plastic film in which a tension is applied to an unstretched film at an appropriate temperature and the molecular orientation is increased along the tensile direction. As the base material, stretched polyethylene terephthalate is preferably used because it is not eroded from the solvent so as to have a practically adverse effect and a uniform orientation of the liquid crystalline composition can be obtained.

  Moreover, as a base material used for this invention, a commercially available polymer film can also be used. For example, the product name “Fujitac” manufactured by Fuji Photo Film Co., Ltd., the product name “Zeonor” manufactured by Nippon Zeon Co., Ltd., and the product name “Arton” manufactured by JSR Co., Ltd. may be used. Further, a polymer film described in JP-A-2001-343529 (WO01 / 37007), for example, a resin composition containing an alternating copolymer composed of isobutylene and N-methylmaleimide and an acrylonitrile / styrene copolymer. Examples include polymer films.

  The substrate used in the present invention is not limited to a single layer, and may be a multilayer. For example, another film such as an organic film (also referred to as an alignment film) such as a polyimide film, a polyamide film, or a polyvinyl alcohol film may be provided on the substrate surface.

  The substrate used in the present invention is preferably used after being subjected to an alignment treatment in order to uniformly align the liquid crystalline composition. Examples of the alignment treatment include a parallel alignment treatment, a vertical alignment treatment, and a tilt alignment treatment as methods for obtaining the homogeneous molecular arrangement, homeotropic molecular arrangement, and tilt molecular arrangement of the liquid crystal compound used in the present invention. It is done. Moreover, a hybrid molecular arrangement | sequence and a twist molecular arrangement | sequence can be obtained combining the said orientation process using two base materials.

  The planar molecular arrangement of the liquid crystalline compound used in the present invention is that when a chiral compound (optically active substance) is added to the liquid crystalline compound, the twisted structure of the liquid crystalline compound having a helical axis perpendicular to the film plane (cholesteric liquid crystal Phase) can be induced. In addition, when the liquid crystal compound has optical activity in the molecular structure, the planar molecular arrangement can be obtained without adding a chiral compound. Typical structures for forming the chiral compound include a helicene type, an asymmetric carbon type, a spiro type, an atropisomeric type, an allene type, a bidentate octahedral complex type, and the like. Moreover, as a specific example of the above chiral compound, trade name “Pariocolor LC756” manufactured by BASF is listed.

  Specific methods of the alignment treatment include a direct alignment treatment method and a substrate surface deformation alignment treatment method. The direct alignment treatment method refers to a method in which the substrate surface is directly treated with an aligning agent, and specific examples include a solution coating method, a plasma polymerization method, and a sputtering method. Examples of the aligning agent include lecithin, stearic acid, carbon, polyimide, polyvinyl alcohol, organic silane, mono- or dibasic carboxylic acid chromium complex, perfluorodimethylcyclohexane, acetylene, polytetrafluoroethylene, and the like.

  The substrate surface deformation orientation treatment method is to form a non-smooth surface by deforming the surface of the substrate in a shape, and utilizing the interaction between the non-smooth surface and the elasticity of the liquid crystal compound, It refers to a method of orientation, and specifically includes a rubbing method, an oblique deposition method, an ion beam method, a plasma method, a pulling method, and the like.

  Other alignment treatment methods include photo-alignment treatment methods in which a substrate coated with a liquid crystalline composition is irradiated with polarized or non-polarized electron beams, visible light or ultraviolet rays to align liquid crystalline compounds, Examples thereof include a polymer stretching treatment method in which a liquid crystalline composition is coated on a stretched film of a plastic resin together with a solvent and oriented. In the present invention, as the alignment treatment method, the same method may be used twice or more, or two or more methods may be used in combination.

  Among the above alignment treatment methods, as the parallel alignment treatment, a rubbing method or a polymer stretching treatment method is preferably used. As the vertical alignment treatment, a solution coating method such as lecithin and stearic acid is preferably used. As the inclined alignment treatment, an oblique vapor deposition method or a photo-alignment treatment method is preferably used.

  The preferred thickness range of the substrate used in the present invention is usually 10 to 300 μm, more preferably 10 to 200 μm, and particularly preferably 10 to 100 μm.

  The method for applying the mixed solution to the substrate used in the present invention is not particularly limited, and a conventionally known coater coating method can be used. The types of coaters used in the above coating methods include reverse roll coaters, forward rotating roll coaters, gravure coaters, knife coaters, rod coaters, slot orifice coaters, curtain coaters, fountain coaters, air doctor coaters, kiss coaters, dip coaters, and bead coaters. , Blade coater, cast coater, spray coater, spin coater, extrusion coater, hot melt coater and the like. Among these, a reverse roll coater, a normal rotation roll coater, a gravure coater, a rod coater, a slot orifice coater, a curtain coater, a fountain coater, and a spin coater are preferably used. If it is the coating system using said coater, the mixed solution used for this invention can be uniformly developed in a thin layer on a base material.

  The coating thickness of the mixed solution is selected depending on the total solid content concentration and viscosity of the mixed solution and the type of coater, but it is usually preferably 2 to 30 μm. More preferably, it is 4-20 micrometers. Especially preferably, it is 7-15 micrometers. If it is said range, the thing excellent in the optical uniformity can be produced.

  In the present invention, the base material coated with the mixed solution is preferably subjected to a drying treatment before radiation irradiation. Although there is no restriction | limiting in particular as temperature in the said drying process (drying temperature), It is preferable to carry out in the temperature range which shows the liquid crystal phase of the said liquid crystalline composition. Moreover, it is preferable that it is below the glass transition temperature (Tg) of a base material. A preferable range of the drying temperature is 50 to 130 ° C. More preferably, it is 80-100 degreeC. If it is said temperature range, a highly uniform retardation film can be produced.

  The time for the drying treatment (drying time) is not particularly limited, but is, for example, 1 to 20 minutes, preferably 1 to 15 minutes, in order to obtain a retardation film having good optical uniformity. More preferably, it is 2 to 10 minutes.

  In the present invention, irradiation with radiation is used to crosslink and cure the liquid crystalline composition used in the present invention by a polymerization reaction.

  The type of radiation is not particularly limited, and examples include gamma rays, X-rays, electron beams, visible rays, infrared rays, and ultraviolet rays. The types of light sources used for radiation irradiation are ultra-high pressure mercury lamp, flash UV lamp, high pressure mercury lamp, low pressure mercury lamp, deep UV lamp, xenon lamp, xenon flash lamp, metal halide lamp, krypton arc lamp, halogen lamp, rare lamp Examples thereof include a gas fluorescent lamp, an infrared lamp, an electrodeless lamp, a dielectric barrier discharge excimer lamp, and the like.

  In the present invention, ultraviolet rays are preferably used as the type of radiation. Examples of light sources suitable for ultraviolet irradiation include ultra high pressure mercury lamps, flash UV lamps, high pressure mercury lamps, low pressure mercury lamps, deep UV lamps, xenon lamps, xenon flash lamps and metal halide lamps. The ultraviolet light emitted from the light source may be non-polarized light or polarized light.

  Although the wavelength of the light source used for the ultraviolet irradiation can be determined according to the wavelength region in which the polymerizable compound used in the present invention has optical absorption, those having a wavelength of 210 nm to 380 nm are usually used. More preferably, it is 250 nm to 380 nm. Usually, the light source is preferably used after cutting a vacuum ultraviolet region of 100 to 200 nm. If it is said range, the liquid crystalline composition used for this invention fully hardens | cures by a polymerization reaction, and can fix the orientation of the said liquid crystalline composition obtained on the base material.

  The position of the light source in the radiation irradiation is not particularly limited, and may be arranged on the side where the mixed solution used in the present invention is applied, or may be arranged on the non-coated substrate side on the other side. Also good. Moreover, the atmosphere in the air in the radiation irradiation is not particularly limited, and examples thereof include an air atmosphere, a nitrogen atmosphere, and an argon atmosphere.

The irradiation amount of the ultraviolet light is preferably 100 to 1500 mJ / cm ² . More preferably, it is 100-800 mJ / cm < ² >. If it is the irradiation light quantity of the said range, the liquid crystalline composition used for this invention will fully harden | cure by a polymerization reaction, and can fix the orientation of the said liquid crystalline composition obtained on the base material.

  The temperature of the atmosphere at the time of radiation irradiation (also referred to as irradiation temperature) is not particularly limited, but while maintaining the liquid crystal composition-isotropic phase transition temperature (Ti) below the liquid crystalline composition used in the present invention, radiation Irradiation is preferably performed. The range of the irradiation temperature is preferably within a range of Ti-5 ° C or less, and more preferably within a range of Ti-10 ° C or less. As said irradiation temperature, the range of 15-90 degreeC is preferable, More preferably, it is 15-60 degreeC. If it is said temperature range, a highly uniform retardation film can be produced.

  The liquid crystal phase-isotropic phase transition temperature (Ti) is obtained by sandwiching the liquid crystalline composition used in the present invention between two glass slides and a temperature controller (for example, product name “LK-600PM” manufactured by Japan High-Tech Co., Ltd.). )) By measuring the temperature when a dark field is obtained from a bright field when observed with a polarizing microscope in which two polarizers are arranged in a crossed Nicols configuration while raising the temperature. Can be sought.

  The specific method of keeping the drying temperature and irradiation temperature constant is not particularly limited, but is an air circulation type constant temperature oven in which hot air or cold air circulates, a heater using microwaves or far infrared rays, temperature control, and the like. For example, a known heating method or temperature control method using a heated roll, a heat pipe roll, or a metal belt can be used.

  In the production method of the present invention, if the drying temperature and the irradiation temperature vary greatly, the thickness unevenness of the coated surface becomes large, resulting in variations in the retardation value of the finally obtained retardation film. Accordingly, it is preferable that the temperature variation in the in-plane direction is as small as possible, and it is more preferable that the temperature variation in the in-plane direction is within a range of ± 1 ° C.

  Next, another retardation film used in combination with the retardation film of the present invention will be described. The retardation film of the present invention can be used by being peeled off from a substrate and laminated on another retardation film via an adhesive layer, an adhesive layer or the like. In addition, the retardation film of the present invention can be used by laminating it with another retardation film through a pressure-sensitive adhesive layer or an adhesive layer together with the base material.

  As said other retardation film, what is excellent in transparency, mechanical strength, thermal stability, moisture shielding property, stability of retardation value, etc. is preferable. Usually, a stretched film of an amorphous polymer of a thermoplastic resin is preferably used.

  Examples of the thermoplastic polymer amorphous polymer used for the other retardation film include cellulose resins such as diacetyl cellulose and triacetyl cellulose, polycarbonate resins, norbornene resins, ethylene / propylene copolymers, and the like. Examples thereof include, but are not limited to, polyolefin resins, amide resins such as nylon and aromatic polyamide, and imide resins such as polyimide and polyimideamide. Further, the above amorphous polymer can also be used after conventionally known polymer modification. Examples of the polymer modification include modifications such as copolymerization, branching, crosslinking, molecular terminals, and stereoregularity. In the present invention, the thermoplastic resin used for the other retardation film is not limited to those exemplified above.

  Further, two or more retardation films of the present invention can be laminated and used at an arbitrary angle. Furthermore, what laminated | stacked 2 or more of retardation films of this invention, and another retardation film can also be used in combination.

  Next, a polarizing plate using the retardation film of the present invention will be described. The retardation film of the present invention can be disposed on at least one side of a polarizer and used as a polarizing plate. In addition, the retardation film of this invention may be laminated | stacked with the polarizer through the adhesive layer, the adhesive bond layer, another retardation film, etc. For example, the retardation film of the present invention can be disposed on at least one side of a polarizer via a substrate and used as a polarizing plate.

  Usually, a polarizing plate having a transparent protective film on one side or both sides of a polarizer is used. When laminating the retardation film of the present invention on at least one surface of a polarizer via an adhesive layer or an adhesive layer, the retardation film may also serve as a transparent protective film. Moreover, when laminating the retardation film of the present invention together with a base material on the surface of a polarizer via an adhesive layer or an adhesive layer, the laminate of the retardation film and the base material serves as a transparent protective film. You may also serve. In this invention, when providing a transparent protective film on both surfaces of a polarizer, the same material may be sufficient as the transparent protective film of front and back, and a different material may be sufficient as it.

  Usually, the polarizer is disposed on one side or both sides of the liquid crystal cell. The retardation film of the present invention is preferably disposed between the polarizer and the liquid crystal cell. Therefore, when the polarizing plate of this invention is laminated | stacked on a liquid crystal cell, it is preferable that the retardation film of this invention is arrange | positioned so as to oppose a liquid crystal cell. At this time, since the transparent protective film on the side facing the liquid crystal cell (near side) has a retardation value in the film plane and a retardation value in the thickness direction may affect the display characteristics of the liquid crystal display device. As the transparent protective film, one having an optimized retardation value is preferably used. Note that the transparent protective film on the side not facing the liquid crystal cell (the far side) does not change the optical characteristics of the liquid crystal display device, and thus is not limited thereto.

  For example, when the transparent protective film on the side (near side) facing the liquid crystal cell laminated on the polarizer has a retardation value in the film plane, the slow axis of the retardation film of the present invention and the absorption of the polarizer When the axes are parallel to each other, the retardation value in the effective film plane of the retardation film of the present invention is designed to be small in advance by the retardation value in the film plane of the transparent protective film. Is preferred.

  As the polarizing plate of the present invention, one in which the slow axis of the retardation film of the present invention is parallel or orthogonal to the absorption axis of the polarizer is preferably used. The angle formed between the slow axis of the polarizing plate and the absorption axis of the polarizer is 0 ° ± 2.0 ° when the slow axis of the polarizing plate is arranged in parallel with the absorption axis of the polarizer. It is preferable. More preferably, it is 0 ° ± 1.0 °. More preferably, it is 0 ° ± 0.5 °. Further, when the slow axis of the polarizing plate is arranged perpendicular to the absorption axis of the polarizer, it is preferably 90 ° ± 2.0 °. More preferably, it is 90 ° ± 1.0 °. More preferably, it is 90 ° ± 0.5 °. As the degree of deviation from these angular ranges increases, the degree of polarization of the polarizing plate decreases, and the contrast decreases when used in a liquid crystal display device.

  The polarizer used in the present invention is not particularly limited, and various types can be used. For example, dichroic substances such as iodine and dichroic dyes are adsorbed on hydrophilic polymer films such as polyvinyl alcohol films, partially formalized polyvinyl alcohol films, and ethylene / vinyl acetate copolymer partially saponified films. And polyene-based oriented films such as a uniaxially stretched product, a polyvinyl alcohol dehydrated product and a polyvinyl chloride dehydrochlorinated product. Among these, a polarizer comprising a polyvinyl alcohol film and a dichroic substance such as iodine is particularly preferable because of its high polarization dichroic ratio. The thickness of these polarizers is not particularly limited, but is generally about 5 to 80 μm.

  A polarizer obtained by dyeing a polyvinyl alcohol film with iodine and uniaxially stretching it can be produced, for example, by dyeing polyvinyl alcohol in an aqueous solution of iodine and stretching it 3 to 7 times the original length. If necessary, it can be immersed in an aqueous solution such as potassium iodide which may contain boric acid, zinc sulfate, zinc chloride and the like. Further, if necessary, the polyvinyl alcohol film may be immersed in water and washed before dyeing.

  In addition to washing the polyvinyl alcohol film surface and anti-blocking agent by washing the polyvinyl alcohol film with water, it also has the effect of preventing unevenness such as uneven dyeing by swelling the polyvinyl alcohol film. is there. Stretching may be performed after dyeing with iodine, may be performed while dyeing, or may be dyed with iodine after stretching. The film can be stretched in an aqueous solution of boric acid or potassium iodide or in a water bath.

  As the transparent protective film used in the present invention, a film excellent in transparency, mechanical strength, thermal stability, moisture shielding property, retardation value stability and the like is preferable. Examples of the material for forming the transparent protective film include thermosetting resins, ultraviolet curable resins, thermoplastic resins, thermoplastic elastomers, and biodegradable plastics. Of these, thermoplastic resins are preferably used. The thermoplastic resin may be an amorphous polymer or a crystalline polymer. From the viewpoint of excellent transparency, an amorphous polymer is preferably used.

  Examples of the amorphous polymer of the thermoplastic resin used for the transparent protective film include cellulose resins such as diacetylcellulose and triacetylcellulose, polyolefin resins such as polycarbonate resins, norbornene resins, and ethylene / propylene copolymers. Examples thereof include resins, amide resins such as nylon and aromatic polyamide, and imide resins such as polyimide and polyimide amide. Further, the above amorphous polymer can also be used after conventionally known polymer modification. Examples of the polymer modification include modifications such as copolymerization, branching, crosslinking, molecular terminals, and stereoregularity. In the present invention, the thermoplastic resin used for the transparent protective film is not limited to those exemplified above.

  Moreover, as a transparent protective film used for this invention, a commercially available polymer film can also be used. For example, the product name “Fujitac” manufactured by Fuji Photo Film Co., Ltd., the product name “Zeonor” manufactured by Nippon Zeon Co., Ltd., and the product name “Arton” manufactured by JSR Co., Ltd. may be used. Further, a polymer film described in JP-A-2001-343529 (WO01 / 37007), for example, a resin composition containing an alternating copolymer composed of isobutylene and N-methylmaleimide and an acrylonitrile / styrene copolymer. Examples include polymer films.

  The thickness of the transparent protective film can be appropriately determined, but is generally about 1 to 500 μm from the viewpoints of workability such as strength and handleability, and thin layer properties. More preferably, it is 5-200 micrometers. Especially preferably, it is 10-150 micrometers. If it is said range, a polarizer will be protected mechanically, and even if it exposes to high temperature and high humidity, a polarizer will not shrink | contract and it can maintain the stable optical characteristic.

  As the retardation value of the transparent protective film, those having Re [590] of 0 to 10 nm are preferably used. More preferably, it is 0-5 nm, Most preferably, it is 0-1 nm. Further, those having Rth [590] of 0 to 200 nm are preferably used. More preferably, it is 0-60 nm, Most preferably, it is 0-30 nm.

  The method for laminating various optical films such as the retardation film, the substrate, and the transparent protective film of the present invention on the polarizer is not particularly limited, and for example, laminating using a conventionally known adhesive or pressure-sensitive adhesive. Can do. An adhesive is preferably used in order to produce a polarizing plate that does not easily peel off due to the influence of humidity or heat. Examples of the adhesive include a solvent volatilization type, a chemical reaction type, and a hot melt type (also referred to as a hot melt type). Among these, as the adhesive used in the present invention, a solvent evaporation type or a chemical reaction type adhesive is preferable.

  In the present invention, the solvent volatilization type adhesive contains a volatile component such as an organic solvent or water, and the volatile component is evaporated in the air or absorbed by an adherend, so that the adhesive strength is increased. It means something that expresses

  In the present invention, the chemical reaction type adhesive refers to an adhesive of a type in which monomer, oligomer and polymer liquid substances are polymerized and cured by a chemical reaction. As means for curing the chemical reaction type adhesive, one that uses moisture in the air, one by adding a curing agent or a catalyst (two-component or more chemical reaction type adhesive), one by heating, and blocking air And those that irradiate ultraviolet rays or electron beams. Among these, a means by which a curing agent or a catalyst is added (a two-component or more chemically reactive adhesive) is preferably used as a curing means.

  As an adhesive used when laminating the various optical films to the polarizer, a polyvinyl alcohol resin is used as a main raw material from the viewpoint of excellent adhesion to the polarizer. A chemical reaction type adhesive to which at least one selected from acids, borax, glutaraldehyde, melamine and oxalic acid is added is particularly preferably used. If it is said thing, the polarizing plate which was hard to peel off by the influence of humidity and a heat | fever, and was excellent in the light transmittance and the polarization degree can be obtained. Specific examples of the polyvinyl alcohol-based resin include, for example, “GOHSEIMER Z” manufactured by Nippon Synthetic Chemical Co., Ltd.

  The polarizing plate of the present invention is preferably provided with a pressure-sensitive adhesive layer or an adhesive layer on both sides or one side in order to facilitate lamination to the liquid crystal cell. The material for forming the pressure-sensitive adhesive layer is not particularly limited. For example, a solvent-type pressure-sensitive adhesive, a non-aqueous emulsion-type pressure-sensitive adhesive, a water-based pressure-sensitive adhesive, a hot-melt pressure-sensitive adhesive, a liquid curable pressure-sensitive adhesive, and a curable type Examples thereof include an adhesive and an adhesive by a calendar method. The material for forming the adhesive layer is not particularly limited. For example, a thermoplastic adhesive, a hot melt adhesive, a rubber adhesive, a thermosetting adhesive, a monomer-reactive adhesive, and an inorganic adhesive. Examples thereof include an adhesive and a natural product adhesive. Among these, a solvent-type pressure-sensitive adhesive is preferably used in the present invention.

  The solvent-type pressure-sensitive adhesive is obtained by dispersing or dissolving one kind of base polymer selected from rubber polymers, acrylic polymers, vinyl polymers, silicone polymers, etc. in an organic solvent such as toluene or ethyl acetate. Say. The solvent-based pressure-sensitive adhesive is based on an acrylic polymer in that it is excellent in transparency, exhibits moderate wettability, cohesiveness, and adhesive properties, and is excellent in weather resistance and heat resistance. An acrylic adhesive is preferably used. The acrylic polymer preferably has a weight average molecular weight (Mw) calculated by the GPC method using tetrahydrofuran as a developing solvent of 30,000 to 2,500,000 in terms of polystyrene.

  As a monomer used for the acrylic polymer, various alkyl (meth) acrylates can be used. For example, (meth) acrylic acid alkyl ester (for example, methyl ester, ethyl ester, propyl ester, butyl ester, 2-ethylhexyl ester, isooctyl ester, isononyl ester, isodecyl ester, dodecyl ester, lauryl ester, tridecyl ester , Pentadecyl ester, hexadecyl ester, heptadecyl ester, octadecyl ester, nonadecyl ester, eicosyl ester, etc., having 1 to 20 carbon atoms). These can be used alone or in combination of two or more. Of these, isononyl ester is preferably used as the monomer used in the acrylic polymer.

  In addition, in order to impart polarity to the acrylic polymer, it is preferable to use a monomer containing a crosslinkable functional group together with the (meth) acrylic acid alkyl ester monomer. Examples of the crosslinkable functional group include a carboxyl group, a hydroxyl group, an amide group, a cyano group, and an epoxy group. The monomer containing the crosslinkable functional group is usually preferably used after being copolymerized with the monomer used in the acrylic polymer.

  Examples of the monomer containing a crosslinkable functional group include (meth) acrylic acid, itaconic acid and the like as the carboxyl group. Examples of the hydroxyl group include hydroxyethyl methacrylate and hydroxypropyl (meth) acrylate. Examples of the amide group include N-methylolacrylamide. Examples of the cyano group include (meth) acrylonitrile. Epoxy groups include glycidyl (meth) acrylate. Of these, (meth) acrylic acid having a carboxyl group is preferably used in that the resulting acrylic pressure-sensitive adhesive has good cohesiveness and adhesiveness.

  The polymerization method for the acrylic polymer is not particularly limited, and a known polymerization method such as solution polymerization, emulsion polymerization, suspension polymerization, or UV polymerization can be employed.

  The acrylic pressure-sensitive adhesive is preferably used by blending a crosslinking agent in order to balance holding power, pressure-sensitive adhesive force, tack and the like. The cross-linking agent is preferably selected depending on the cross-linkable functional group introduced into the acrylic polymer. Examples of the crosslinking agent include polyisocyanate compounds, diisocyanates, polyamines, acids, acid anhydrides, dialdehydes, melamine resins, urea resins, and epoxy resins. Furthermore, a catalyst, a tackifier, a plasticizer, a filler, an antioxidant, an ultraviolet absorber, a silane coupling agent, and the like can be appropriately used for the acrylic pressure-sensitive adhesive as necessary.

  The method for forming the pressure-sensitive adhesive layer and the adhesive layer used in the present invention is not particularly limited, and is a method in which a pressure-sensitive adhesive is applied to a release film, dried and then transferred to the retardation film and polarizing plate of the present invention ( Transfer method), a method of directly applying and drying an adhesive on the retardation film and the polarizing plate (direct copying method), and the like.

  Although there is no restriction | limiting in particular as the range of the preferable thickness of the adhesive layer and adhesive layer used for this invention, It determines suitably according to the adhesive force and the surface state of the said retardation film. For example, 5-100 micrometers is preferable, More preferably, it is 10-50 micrometers. If it is said range, sufficient adhesive force can be obtained.

  The exposed surfaces of the pressure-sensitive adhesive layer and the adhesive layer are covered with a release paper or a release film (also referred to as a separator) for the purpose of preventing the contamination until practical use. Thereby, it can prevent contacting an adhesive layer and an adhesive bond layer in a usual handling state. As the separator, for example, an appropriate thin leaf body such as a plastic film, rubber sheet, paper, cloth, non-woven fabric, net, foamed sheet, metal foil, laminate thereof, or the like, silicone-based, long mirror alkyl-based, fluorine An appropriate one according to the prior art, such as a system or a coating treatment with an appropriate release agent such as molybdenum sulfide, can be used.

  The surface of the transparent protective film to which the polarizer is not adhered can be subjected to a hard coat treatment, an antireflection treatment, an antisticking treatment, or a diffusion treatment (also referred to as an antiglare treatment). The hard coat treatment is performed for the purpose of preventing scratches on the surface of the polarizing plate. For example, a cured film having excellent hardness and slipping properties due to UV-curable resin such as acrylic and silicone is applied to the transparent protective film. Can be formed on the surface. The antireflection treatment is performed for the purpose of preventing reflection of external light on the surface of the polarizing plate. The sticking prevention treatment is performed for the purpose of preventing adhesion with an adjacent layer. The anti-glare treatment is performed for the purpose of preventing the outside light from being reflected on the surface of the polarizing plate and obstructing the visual recognition of the light transmitted through the polarizing plate. For example, the surface is roughened by a sandblasting method or an embossing method. It can be formed by imparting a fine concavo-convex structure to the surface of the transparent protective film by an appropriate method such as a blending method of transparent fine particles. The antiglare layer may also serve as a diffusion layer (viewing angle expanding function or the like) for diffusing the light transmitted through the polarizing plate to expand the viewing angle.

  Next, another optical member used in combination with the retardation film or polarizing plate of the present invention will be described. Although there is no limitation in particular as said other optical member, For example, what used the said hard-coat process, the antireflection process, the sticking prevention process, and the diffusion process as the optical film separately is mentioned. When the retardation film or polarizing plate of the present invention is used for a transmissive or transflective liquid crystal display device, a commercially available brightness enhancement film (a polarized light separation film having a polarization selective layer, for example, manufactured by Sumitomo 3M Co., Ltd.). In combination with D-BEF, etc., a display device with higher display characteristics can be obtained.

  The retardation film, polarizing plate, and other optical members can be formed by sequentially laminating them separately in the manufacturing process of the liquid crystal display device. It is preferable because the manufacturing efficiency of a liquid crystal display device and the like can be improved with excellent properties.

  The retardation film and polarizing plate of the present invention are preferably laminated on at least one side of a liquid crystal cell and used as a liquid crystal panel.

  In addition, the retardation film and polarizing plate of the present invention include a liquid crystal display device such as a personal computer, a liquid crystal television, a mobile phone, and a personal digital assistant (PDA), an organic electroluminescence display (organic EL), a projector, a projection television, and a plasma television. It can be used for an image display device. Especially, it is preferable that the retardation film, polarizing plate, and liquid crystal panel of this invention are used for a liquid crystal display device.

  The type of the liquid crystal display device is not particularly limited, and any of a transmissive type, a reflective type, and a reflective transflective type can be used. Examples of liquid crystal cells used in the liquid crystal display device include twisted nematic (TN) mode, super twisted nematic (STN) mode, horizontal alignment (ECB) mode, vertical alignment (VA) mode, and in-plane switching (IPS) mode. And various liquid crystal cells such as a liquid crystal cell of a bend nematic (OCB) mode, a ferroelectric liquid crystal (SSFLC) mode, and an antiferroelectric liquid crystal (AFLC) mode. Among these, the retardation film and the polarizing plate of the present invention are particularly preferably used for TN mode, VA mode, IPS mode, and OCB mode liquid crystal display devices.

  The twisted nematic (TN) mode liquid crystal cell is a liquid crystal cell in which a nematic liquid crystal having positive dielectric anisotropy is sandwiched between two substrates, and the liquid crystal molecular alignment is 90 by surface alignment treatment of the glass substrate. The one that is twisted. Specific examples include the liquid crystal cell described in “Liquid Crystal Dictionary” on page 158 (1989) and the liquid crystal cell described in JP-A-63-279229.

  The vertical alignment (VA) mode liquid crystal cell uses a voltage-controlled birefringence (ECB) effect, and nematic liquid crystal having a negative dielectric anisotropy between transparent electrodes when no voltage is applied. Means a vertically aligned liquid crystal cell. Specific examples include liquid crystal cells described in JP-A-62-210423 and JP-A-4-153621. In addition, as described in JP-A No. 11-258605, the VA mode liquid crystal cell includes a substrate provided with a slit in a pixel or a substrate on which a protrusion is formed in order to enlarge a viewing angle. By using it, it may be a multi-domain MVA mode liquid crystal cell. Further, as described in JP-A-10-123576, a VATN mode liquid crystal in which a chiral agent is added to a liquid crystal, the liquid crystal is substantially vertically aligned when no nematic liquid crystal voltage is applied, and twisted multi-domain alignment is applied when a voltage is applied. It may be a cell.

  The in-plane switching (IPS) mode liquid crystal cell is a so-called sandwich cell in which a liquid crystal is sealed between two parallel substrates using a voltage controlled birefringence (ECB) effect. A liquid crystal which responds to a nematic liquid crystal that is homogeneously aligned in the absence of an electric field (also referred to as a transverse electric field) parallel to the substrate. Specifically, Techno Times Publishing “Monthly Display July” p. 83-p. 88 (1997 edition) and “Liquid Crystal vol.2 No. 4” published by the Japanese Liquid Crystal Society. 303-p. 316 (1998 edition), when the upper and lower polarizing plates are arranged orthogonally so that the major axis of the liquid crystal molecules and the polarizing axis of the incident side polarizing plate coincide with each other, the display is completely black without an electric field. When there is an electric field, the liquid crystal molecules are those that can obtain transmittance according to the rotation angle by rotating while keeping parallel to the substrate.

  The liquid crystal cell of the bend nematic (OCB: Optically Compensated Bend or Optically Compensated Birefringence) mode is a voltage-controlled birefringence (ECB: Electrically Controlled Birefringence Effect). The liquid crystal is a bend-aligned liquid crystal cell in which twisted alignment exists in the center when no voltage is applied. The OCB mode liquid crystal cell is also referred to as a “π cell”. Specific examples include those described in Kyoritsu Publishing Co., Ltd. “Next Generation Liquid Crystal Display” (2000), pages 11 to 27, and those described in JP-A-7-084254.

  By using the retardation film and polarizing plate of the present invention in such various liquid crystal cells, contrast, hue, and viewing angle characteristics can be improved, and the functions can be maintained for a long period of time.

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. The analysis methods used in the examples are as follows.
(1) Measuring method of birefringence index (Δn) in film plane Refractive index measured with light of wavelength 589 nm at 23 ° C. using Abbe refractometer [product name “DR-M4” manufactured by Atago Co., Ltd.] I asked more.
(2) Measuring method of phase difference value (Re [590]) Using a spectroscopic ellipsometer [manufactured by JASCO Corporation, product name “M-220”], it was measured with light having a wavelength of 590 nm at 23 ° C.
(3) Measuring method of light transmittance Using a UV-visible spectrophotometer [manufactured by JASCO Corporation, product name “V-560”], the light transmittance was measured with light having a wavelength of 590 nm at 23 ° C.
(4) Thickness measurement method of retardation film It measured using the spectrophotometer for thin films [Otsuka Electronics Co., Ltd. product name "instant multiphotometry system MCPD-2000"].
(5) Ultraviolet irradiation method The ultraviolet irradiation apparatus which uses the metal halide lamp whose light intensity of wavelength 365nm is 120 mW / cm < ² > as a light source was used.

[Production example]
4- (4-propylcyclohexyl) phenol (53.60 g, 0.25 mol), 2-chloroethanol (59.30 g, 0.74 mol), potassium carbonate (101.70 g, 0.74 mol), potassium iodide (12 .20 g, 73.6 mmol) and N, N-dimethylformamide (250 mL) were mixed in an eggplant flask and kept at 90 ° C. and stirred for 8 hours. After adding ethyl acetate (400 mL) to the above reaction solution, the organic phase mainly composed of ethyl acetate was washed 3 times with water (300 mL × 3 times), once with saturated brine (50 mL), and then with magnesium sulfate. Dehydrated. Ethyl acetate was removed from the organic phase under reduced pressure to obtain a light brown crude product. The crude product was recrystallized from hexane and dried to obtain 42.6 g (yield: 66% by weight) of 2- [4- (4-propylcyclohexyl) phenoxy] ethanol as white crystals.

  2- [4- (4-propylcyclohexyl) phenoxy] ethanol (30.20 g, 0.12 mol), dehydrated tetrahydrofuran (120 mL) containing BHT in a trace amount as a polymerization inhibitor, triethylamine (32.1 mL, 0.23 mol). The mixture was mixed in a 500 mL three-necked flask and cooled with ice water while stirring. Distilled acrylic acid chloride (14.6 ml, 0.18 mol) was added in small portions and stirred for 8 hours while maintaining the temperature at room temperature. The reaction solution was poured into 500 mL of saturated brine, and 1N hydrochloric acid was added thereto until the reaction solution became acidic (pH 1 to 4). The reaction solution was extracted with ethyl acetate (400 mL × twice), and an organic phase mainly composed of ethyl acetate was collected. The organic phase was washed 3 times with water (300 mL × 3 times), once with saturated brine (50 mL), and dehydrated with magnesium sulfate. Ethyl acetate was removed from the organic phase under reduced pressure to obtain a crude product. Thereafter, the crude product is purified by silica gel column chromatography using dichloromethane as a developing solvent, and the dichloromethane is removed under reduced pressure to obtain a polymerizable compound (A) represented by the following formula (2) as a white crystal. 30.6 g (yield: 84% by weight) was obtained.

前記式（２）で表される化合物の核磁気共鳴スペクトルデータ（¹Ｈ−ＮＭＲ）を以下に示す。ここで、¹Ｈ−ＮＭＲの測定は、日本電子（株）製（ＬＡ４００）を用い、少量の試料を、観測核：１Ｈ、周波数：４００ＭＨｚ、パルス幅：４５度、パルスの繰り返し時間：１０秒、ケミカルシフトの基準：７．２５ｐｐｍ、測定溶媒：重クロロホルム、測定温度：室温の条件で測定したものである。
¹Ｈ−ＮＭＲ（４００Ｈｚ、ＣＤＣｌ₂）：δ ０．８９（ｔ、３Ｈ、Ｊ＝７．２Ｈｚ）、０．９７−１．０８（ｍ、２Ｈ）、１．１７−１．４５（ｍ、７Ｈ）、１．８１−１．８８（ｍ、４Ｈ）、２．４０（ｔｔ、１Ｈ、Ｊ＝３．２、１２．２Ｈｚ）、４．１８（ｔ、２Ｈ、Ｊ＝４．８Ｈｚ）、４．４９（ｔ、２Ｈ、Ｊ＝４．８Ｈｚ）、５．８４（ｄｄ、１Ｈ、Ｊ＝１．２、１０．３Ｈｚ）、６．１５（ｄｄ、１Ｈ、Ｊ＝１０．３、１７．４Ｈｚ）、６．４３（ｄｄ、１Ｈ、Ｊ＝１．２、１７．４Ｈｚ）、６．８２−６．８６（ｍ、２Ｈ）、７．０９−７．１４（ｍ、２Ｈ）

The nuclear magnetic resonance spectrum data ( ¹ H-NMR) of the compound represented by the formula (2) is shown below. Here, measurement of ¹ H-NMR uses JEOL Co., Ltd. (LA400), a small amount of sample: observation nucleus: 1H, frequency: 400 MHz, pulse width: 45 degrees, pulse repetition time: 10 seconds Chemical shift standard: 7.25 ppm, measurement solvent: deuterated chloroform, measurement temperature: measured at room temperature.
¹ H-NMR (400 Hz, CDCl ₂ ): δ 0.89 (t, 3H, J = 7.2 Hz), 0.97-1.08 (m, 2H), 1.17-1.45 (m, 7H), 1.81-1.88 (m, 4H), 2.40 (tt, 1H, J = 3.2, 12.2 Hz), 4.18 (t, 2H, J = 4.8 Hz), 4.49 (t, 2H, J = 4.8 Hz), 5.84 (dd, 1H, J = 1.2, 10.3 Hz), 6.15 (dd, 1H, J = 10.3, 17. 4 Hz), 6.43 (dd, 1H, J = 1.2, 17.4 Hz), 6.82-6.86 (m, 2H), 7.09-7.14 (m, 2H)

[Example 1]
A 5% by weight polyvinyl alcohol aqueous solution is applied onto a glass plate using a spin coater (coating conditions: rotation speed 2000 ± 1 rpm, 10 seconds), dried at 150 ± 1 ° C. for 1 hour, and then applied onto the glass plate. A polyvinyl alcohol film was formed. Next, the surface of the polyvinyl alcohol film on the glass plate was rubbed in one direction with a rubbing cloth made of a felt material to be rubbed.

Next, 40 parts by weight of the polymerizable compound (A) obtained in the production example, a liquid crystalline compound having a phenylbenzoate group as a mesogenic group and two acryloyl groups at the molecular terminals [trade name “PalicolorLC242” manufactured by BASF Corporation] ] 60 parts by weight, 3 parts by weight of a photopolymerization initiator [trade name “Irgacure 907” manufactured by Ciba Specialty Chemicals Co., Ltd.], and an acrylic acid copolymer-based leveling agent [trade name “BYK361” manufactured by BYK Chemie Co., Ltd.] ] Is mixed with a liquid crystalline composition (containing 38.8 (weight ratio) of the polymerizable compound (A) with respect to the liquid crystalline composition 100), cyclopentanone (boiling point 131 ° C.). ) A mixed solution having a total solid content of 34% by weight was dissolved in 200 parts by weight. The above mixed solution is applied to the surface of the rubbed polyvinyl alcohol film on the glass plate with a spin coater (coating conditions: rotation speed 1500 ± 1 rpm, 10 seconds) to form a homogeneous molecular arrangement of the liquid crystalline compound. did.

Then, after drying the base material coated with the above mixed solution in a 90 ± 1 ° C. air circulation type thermostatic oven for 3 minutes, it is cooled to room temperature, and the mixed solution is applied in an air atmosphere at 30 ° C. The liquid crystal composition was cured by a polymerization reaction by irradiating ultraviolet rays with an irradiation light amount of 600 mJ / cm ² from the side, and the homogeneous molecular arrangement of the liquid crystal compound was fixed. The thickness of the retardation film obtained on the glass plate is 2.0 μm, the light transmittance is 92%, and the birefringence in the film plane: (nx−ny) is 0.089 (nx = 1.624, ny = 1.535, nz = 1.535), and Re [590] was 178.0 nm.

[Example 2]
35 parts by weight of the polymerizable compound (A) obtained in the production example, 60 parts by weight of a liquid crystal compound [trade name “Paliocolor LC242” manufactured by BASF Co., Ltd.], trisacryloyloxyethyl phosphate [Osaka Organic as a trifunctional polymerizable compound Chemical Industry Co., Ltd. trade name “Biscoat 3PA” 5 parts by weight, photopolymerization initiator [Ciba Specialty Chemicals Co., Ltd. trade name “Irgacure 907”] 3 parts by weight, and leveling agent [Bikchemy Co., Ltd. A liquid crystalline composition mixed with 0.05 part by weight of the trade name “BYK361” (containing 34.0 (weight ratio) of the polymerizable compound (A) with respect to the liquid crystalline composition 100) is added to cyclopenta Dissolved in 200 parts by weight of non (boiling point 131 ° C.), a mixed solution having a total solid concentration of 34% by weight was prepared. Using the mixed solution, the homogeneous molecular arrangement of the liquid crystal compound was fixed in the same manner as in Example 1. The thickness of the retardation film obtained on the glass plate is 1.9 μm, the light transmittance is 92%, the birefringence in the film plane: (nx−ny) is 0.057 (nx = 1.598, ny = 1.541, nz = 1.541), and Re [590] was 108.3 nm.

[Comparative Example 1]
100 parts by weight of a liquid crystal compound [trade name “Paliocolor LC242” manufactured by BASF Corporation], 3 parts by weight of a photopolymerization initiator [trade name “Irgacure 907” manufactured by Ciba Specialty Chemicals Co., Ltd.], and a leveling agent [manufactured by Big Chemie] A liquid crystalline composition (containing no polymerizable compound (A)) mixed with 0.05 part by weight of the trade name “BYK361”] is dissolved in 200 parts by weight of cyclopentanone (boiling point 131 ° C.) to obtain a total solid content. A mixed solution having a concentration of 34% by weight was prepared. Using the mixed solution, the homogeneous molecular arrangement of the liquid crystal compound was fixed in the same manner as in Example 1. The thickness of the retardation film obtained on the glass plate is 2.1 μm, the light transmittance is 92%, and the birefringence in the film plane: (nx−ny) is 0.131 (nx = 1.654, ny = 1.523, nz = 1.523) and Re [590] was 275.1 nm.

[Comparative Example 2]
50 parts by weight of the polymerizable compound (A) obtained in the production example, 50 parts by weight of a liquid crystal compound [trade name “Paliocolor LC242” manufactured by BASF Corporation], and a photopolymerization initiator [manufactured by Ciba Specialty Chemicals Co., Ltd. 3 parts by weight of “Irgacure 907”] and 0.05 parts by weight of a leveling agent [trade name “BYK361” manufactured by Big Chemie Co., Ltd.] were mixed (the polymerizable compound (with respect to the liquid crystalline composition 100) A) 48.5 (weight ratio)
In the mixture) was dissolved in 200 parts by weight of cyclopentanone (boiling point 131 ° C.) to prepare a mixed solution having a total solid content of 34% by weight. An experiment was attempted using the above mixed solution in the same manner as in Example 1, but a homogeneous molecular arrangement of the above liquid crystalline compound was not obtained. Moreover, since the film obtained on the glass plate became cloudy and wasotropic, it was not preferable as a retardation film.

[Example 3]
The mixed solution used in Example 1 was coated on a stretched polyethylene terephthalate film [trade name “Lumirror S27-E” manufactured by Toray Industries, Inc.] having a thickness of 75 μm using a rod coater (coating thickness: 4.6 μm), a homogeneous molecular arrangement of the liquid crystalline compound was formed. Then, after drying the base material coated with the above mixed solution in a 90 ± 1 ° C. air circulation type thermostatic oven for 3 minutes, it is cooled to room temperature, and the mixed solution is applied in an air atmosphere at 30 ° C. The liquid crystal composition was cured by a polymerization reaction by irradiating ultraviolet rays with an irradiation light amount of 600 mJ / cm ² from the side, and the homogeneous molecular arrangement of the liquid crystal compound was fixed. The thickness of the retardation film obtained on the polyethylene terephthalate film is 1.58 μm, the birefringence in the film plane: (nx−ny) is 0.089 (nx = 1.624, ny = 1.535, nz = 1.535). The retardation film was peeled off from the polyethylene terephthalate film and adhered onto a glass plate via an adhesive to prepare a 10 cm × 10 cm sample. As shown in FIG. 1, when Re [590] was measured at nine locations in the plane at equal intervals, the average value of Re [590] was 140.8 nm and the variation of Re [590] was ± 3.5 nm.

[Example 4]
Using the mixed solution used in Example 2, the homogeneous molecular arrangement of the liquid crystal compound was fixed in the same manner as in Example 3 (coating thickness: 13.9 μm). The thickness of the retardation film obtained on the polyethylene terephthalate film is 4.74 μm, and the birefringence in the film plane: (nx−ny) is 0.057 (nx = 1.598, ny = 1.541, nz = 1.541). A 10 cm × 10 cm sample was produced in the same manner as in Example 3. The average value of Re [590] was 270.1 nm, and the variation of Re [590] was ± 2.7 nm.

[Comparative Example 3]
Using the mixed solution used in Comparative Example 1, the homogeneous molecular arrangement of the liquid crystal compound was fixed by the same method as in Example 3 (coating thickness: 3.2 μm). Further, the thickness of the retardation film obtained on the polyethylene terephthalate film is 1.08 μm, and the birefringence in the film plane: (nx−ny) is 0.131 (nx = 1.654, ny = 1.523, nz = 1.523). A 10 cm × 10 cm sample was produced in the same manner as in Example 3. The average value of Re [590] was 141.2 nm, and the variation of Re [590] was ± 6.8 nm.

[Comparative Example 4]
Using the mixed solution used in Comparative Example 1, the homogeneous molecular arrangement of the liquid crystal compound was fixed in the same manner as in Example 3 (coating thickness: 6.1 μm). Further, the thickness of the retardation film obtained on the polyethylene terephthalate film is 2.06 μm, and the birefringence in the film plane: (nx−ny) is 0.131 (nx = 1.654, ny = 1.523, nz = 1.523). A 10 cm × 10 cm sample was produced in the same manner as in Example 3. The average value of Re [590] was 270.5 nm, and the variation of Re [590] was ± 6.0 nm.

[Evaluation]
As described above, the retardation film obtained by aligning and curing the liquid crystalline composition containing the polymerizable compound of the present invention obtained in Examples 1 and 2 has a birefringence in the film plane of 0. 0.089 and 0.057, which are smaller than those of a conventional retardation film using a commercially available liquid crystalline compound (birefringence index in the film plane: 0.131). Further, the light transmittance was 92% and excellent in transparency. On the other hand, since the film obtained in Comparative Example 2 used the liquid crystalline composition containing 48.5 (weight ratio) of the polymerizable compound of the present invention with respect to the liquid crystalline composition 100, A homogeneous molecular arrangement was not obtained, and the film was cloudy and isotropic, which was not preferable as a retardation film. In the retardation films obtained in Examples 3 and 4, the dispersion of retardation values in the film plane (± 3.5 nm and ± 2.7 nm, respectively) is relative to the average value of retardation values in the film plane. , Each of which is in the range of ± 2.5% and ± 1.0%, and the in-plane retardation value variation of the conventional retardation films obtained in Comparative Examples 3 and 4 (± 4.8% respectively) , ± 2.2%), the uniformity was excellent. Therefore, an extremely high coating accuracy was not required, and a thin retardation film could be produced with high productivity.

  The retardation film of the present invention has high transparency and can reduce variations in retardation values within the film plane. In addition, the production method of the present invention is extremely useful industrially because it can produce a thin retardation film with small variation in retardation value in the film plane even when coating with conventional coating accuracy. It can be said that there is.

It is the schematic of the sample for measuring the retardation value in the film plane of the retardation film of this invention.

Explanation of symbols

1 Measurement point of retardation value in the film surface

Claims (10)

A retardation film obtained by aligning and curing a liquid crystalline composition containing a polymerizable compound represented by the following formula (2) and a liquid crystalline compound.

2. The retardation film according to claim 1, wherein the retardation film has a light transmittance of 80% or more as measured with light having a wavelength of 590 nm at 23 ° C. 3 . The thickness of the said retardation film is 1.1-15 micrometers, The retardation film as described in any one of Claim 1 or 2 characterized by the above-mentioned. According to any one of claims 1 to 3 birefringence in the film plane measured with light having a wavelength of 589nm is characterized in that it is a 0.030 to 0.095 at 23 ° C. of the phase difference film Retardation film. 5. The retardation film according to claim 1 , wherein a retardation value in the film plane measured with light having a wavelength of 590 nm at 23 ° C. of the retardation film is 50 to 800 nm. The polarizing plate which has arrange | positioned the retardation film as described in any one of Claims 1-5 at least on the one side of the polarizer. A liquid crystal panel in which the polarizing plate according to claim 6 is disposed on at least one side of a liquid crystal cell. The liquid crystal panel according to claim 7, wherein the liquid crystal cell is in any one of a TN mode, a VA mode, an IPS mode, and an OCB mode. A liquid crystal display device comprising the liquid crystal panel according to claim 7 . A method for producing a retardation film according to any one of claims 1 to 5 , wherein a liquid crystalline composition containing a polymerizable compound represented by the following formula (2) and a liquid crystalline compound is used together with a solvent. A step of coating and aligning on the material, and a step of irradiating the substrate coated with the liquid crystalline composition with radiation to cure the liquid crystalline composition. 10 to 45 (weight ratio) of a functional compound is contained, A method for producing a retardation film.

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