JP4297436B2 - Liquid crystalline di (meth) acrylate compound and retardation film, optical film, polarizing plate, liquid crystal panel and liquid crystal display device using the same - Google Patents

Description

  The present invention relates to a liquid crystalline di (meth) acrylate compound and a retardation film, an optical film, a polarizing plate, a liquid crystal panel, and a liquid crystal display device using the same.

  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. As the retardation film, a film obtained by stretching a polymer film such as polycarbonate or polystyrene has been conventionally used.

  However, since the polymer film usually has a thickness of about 40 to 100 μm, for example, when applied to a liquid crystal display device that is desired to be thin, a thinner retardation film is desired.

  Thus, as an alternative to the stretched polymer film, a retardation film using a liquid crystal monomer has attracted attention (see, for example, Non-Patent Document 1). Usually, the retardation value of the retardation film is determined by the product of the birefringence (Δn) and the thickness. However, since the liquid crystal monomer has a large Δn, it is necessary to obtain a predetermined retardation value. This has the advantage that the thickness of the retardation film can be reduced.

  As the retardation film as described above, for example, an optical film in which a mixed solution containing a liquid crystal monomer is coated on a substrate and uniformly oriented, and then cured by irradiation with ultraviolet rays has been proposed ( For example, see Patent Document 1). When such an optical film is used as a retardation film, the properties required for the liquid crystal monomer include not only excellent transparency of the cured film, but also good solubility in a solvent, and the liquid crystal monomer. Are uniformly oriented, the crosslinkability (curability) with ultraviolet rays is good, and the orientation state is uniformly fixed.

  However, since the conventional liquid crystal monomer has a Δn larger than 0.10, when it is intended to produce a retardation film having a small retardation value using the liquid crystal monomer, the design value of the film thickness is usually about 1 μm. The thickness was extremely small, and the thickness control was extremely difficult. In addition, a small variation in thickness appears as a large nonuniformity of the retardation value, which deteriorates the display uniformity of the liquid crystal display device.

In particular, in recent years, liquid crystal monitors, liquid crystal televisions, and the like have rapidly increased in size and functionality, and various optical films such as polarizing plates and retardation films used in these have further improved characteristics and quality. Improvement is desired. Under such circumstances, development of a retardation film using a liquid crystal monomer having a smaller Δn (for example, 0.10 or less) than the conventional liquid crystal monomer has been awaited.
JP-A-8-283718 Macromolecules, 1995, 28, 3313-3327

  The present invention has been made in view of such a conventional technique, and is excellent in transparency, is not required to have extremely high coating accuracy, is excellent in productivity, and has a good optical uniformity. It is an object of the present invention to provide a liquid crystalline di (meth) acrylate compound capable of obtaining a film and a retardation film using the same. Another object of the present invention is to provide an optical film, a polarizing plate, a liquid crystal panel, and a liquid crystal display device using the retardation film.

  The inventors of the present invention have intensively studied to solve the above problems, and as a result, find out that the above problems can be solved if a retardation film is produced using a specific polymerizable liquid crystal monomer, and the present invention is completed. It came.

ここで、前記式（Ｉ）において、Ｒ^１及びＲ^２はそれぞれ独立して水素原子又はメチル基を示し、Ｒ^３及びＲ^４はそれぞれ独立して炭素数２〜１２のアルキレン基を示し、Ｒ^５及びＲ^６はそれぞれ独立して−Ｏ−ＣＯ−又は−ＣＯ−Ｏ−を示し、Ａ^１及びＡ^２はそれぞれ独立して−Ｏ−又は−Ｏ−ＣＯ−Ｏ−を示し、Ｘは、無置換のフェニル基又はナフチル基、或いは、無置換のチオフェニル基、フラニル基又はピロリル基を示す。 That is, the present invention provides a liquid crystalline di (meth) acrylate compound represented by the following formula (I) and a composition containing the liquid crystalline di (meth) acrylate compound on a substrate. A retardation film obtained by fixing is provided.

Here, in Formula (I), R ¹ and R ² each independently represent a hydrogen atom or a methyl group, R ³ and R ⁴ each independently represent an alkylene group having 2 to 12 carbon atoms, R ⁵ and R ⁶ each independently represent —O—CO— or —CO—O—, A ¹ and A ² each independently represents —O— or —O—CO—O—, and X represents An unsubstituted phenyl group or naphthyl group, or an unsubstituted thiophenyl group, furanyl group or pyrrolyl group is shown.

X may be an unsubstituted phenyl group . R ³ and R ⁴ can be independently an alkylene group having 2 to 6 carbon atoms, and X can be a phenyl group.

  Moreover, it is preferable that the birefringence in the wavelength 589nm of the said liquid crystalline di (meth) acrylate compound is 0.01-0.10.

Preferably, the said composition is hardened | cured by irradiating an ultraviolet-ray, and the irradiation amount of the said ultraviolet-ray shall be 100-1500mJ / cm < ² >.

  The thickness of the composition after being oriented and fixed on the substrate is preferably 1 to 10 μm.

  Preferably, the light transmittance of the retardation film at a wavelength of 590 nm is 80% or more.

Further, it is preferable that the retardation value Re (590) in the retardation film plane at the wavelength of 590 nm satisfies the following formula (1).
80 nm ≦ Re (590) ≦ 800 nm (1)
Here, Re (590) = (nx−ny) × d, where nx is the refractive index in the slow axis direction of the retardation film (the direction in which the refractive index in the retardation film is maximized), and ny is The refractive index in the fast axis direction of the retardation film, and d [nm] means the thickness of the retardation film.

  Moreover, this invention is provided also as an optical film characterized by laminating | stacking the said retardation film.

  The present invention is also provided as a polarizing plate in which the retardation film or the optical film is disposed on at least one side of a polarizer.

  Moreover, this invention is provided also as a liquid crystal panel provided with the said retardation film, the said optical film, or the said polarizing plate, and a liquid crystal cell.

  Preferably, the liquid crystal cell is in a TN mode, a VA mode, an IPS mode, or an OCB mode.

  Furthermore, the present invention is also provided as a liquid crystal display device comprising the liquid crystal panel.

  According to the liquid crystalline di (meth) acrylate compound according to the present invention, it is excellent in transparency, can suppress unevenness in retardation value, and yet has excellent productivity without requiring extremely high coating accuracy. A film and an optical film, a polarizing plate, a liquid crystal panel, and a liquid crystal display device using the film can be obtained.

ここで、前記式（Ｉ）において、Ｒ^１及びＲ^２はそれぞれ独立して水素原子又はメチル基を示し、Ｒ^３及びＲ^４はそれぞれ独立して炭素数２〜１２のアルキレン基を示し、Ｒ^５及びＲ^６はそれぞれ独立して−Ｏ−ＣＯ−又は−ＣＯ−Ｏ−を示し、Ａ^１及びＡ^２はそれぞれ独立して−Ｏ−又は−Ｏ−ＣＯ−Ｏ−を示し、Ｘは芳香族置換基を示す。 The retardation film according to the present invention is a liquid crystal that is a polymerizable liquid crystal monomer having a specific structure represented by the following formula (I) in which the phenylene group at the center of the main chain is substituted with an acetylene group having an aromatic group. It is obtained by aligning and fixing a composition containing a functional di (meth) acrylate compound (hereinafter referred to as liquid crystal monomer (I)) on a substrate.

Here, in Formula (I), R ¹ and R ² each independently represent a hydrogen atom or a methyl group, R ³ and R ⁴ each independently represent an alkylene group having 2 to 12 carbon atoms, R ⁵ and R ⁶ each independently represent —O—CO— or —CO—O—, A ¹ and A ² each independently represents —O— or —O—CO—O—, and X represents a fragrance. Indicates a group substituent.

The liquid crystal monomer (I) has a structure in which the ortho position (lateral position) of the phenylene group at the center of the main chain is substituted with an acetylene group having an aromatic group.
Here, a structure in which two hydrogen atoms of acetylene represented by the following formula (II) are both substituted with a phenyl group is called a tolan skeleton.

The central part of the liquid crystal monomer (I) is represented by the following formula (III) (in the formula (III), X is the same as X in the formula (I) described above): The structure is almost the same as that of the above-mentioned tolane skeleton, which is “aromatic group bonded to phenylene group-acetylene-lateral position”.

When light is incident on a retardation film obtained by aligning and fixing a composition containing such a liquid crystal monomer (I) on a substrate, extraordinary rays are emitted in the direction of the main chain and ordinary rays in the direction of the lateral position. Propagate. Here, the lateral position of the liquid crystal monomer (I) is substituted with an acetylene group having an aromatic group, and has a structure (tolane skeleton form) almost the same as that of the tolan skeleton in combination with the phenylene group in the main chain. For this reason, for example, when compared with the case where the lateral position is unsubstituted and substituted with a methyl group, the tolan skeleton aspect is sterically bulky and the polarizability is large, so that the refractive index (n _e ) of extraordinary rays is small, ordinary refractive index of the opposite _{(n o)} increases result, it is considered that the birefringence Δn ₍₌ n e -n _o) becomes small. In other words, by Tran skeleton aspect, there is an electron cloud by conjugation to (there is a high partial electron density), thereby to rate delay of an ordinary ray is generated, the refractive index for the ordinary ray is changed (n _o is large Is considered).

In the formula (I), R ¹ and R ² each independently represent a hydrogen atom or a methyl group. From the viewpoint of rapid crosslinking of the liquid crystal monomer (I), R ¹ and R ² R ² is preferably a hydrogen atom.

R ³ and R ⁴ each independently represent an alkylene group having 2 to 12 carbon atoms. From the viewpoint of obtaining a wide liquid crystal temperature range and good orientation, R ³ and R 4 ⁴ is preferably an alkylene group having 2 to 6 carbon atoms.

Furthermore, R ⁵ and R ⁶ each independently represent —O—CO— or —CO—O—. From the viewpoint of the stability and cost of the raw material, R ⁵ and R ⁶ are Is preferably -O-CO-.

  X represents an aromatic substituent. From the viewpoint of obtaining an effect of reducing Δn and obtaining good alignment of the liquid crystal monomer, X is unsubstituted or substituted (one of the substituents). Preferably a phenyl group or a naphthyl group having one or two carbon atoms substituted with a nitrogen atom), or an unsubstituted or substituted thiophenyl group, furanyl group or pyrrolyl group, Particularly preferred is a phenyl group.

  From the above points, in the present invention, among the liquid crystal monomers (I), X is unsubstituted or substituted (one or two carbon atoms of the substituent are substituted with nitrogen atoms) Or a thiophenyl group, furanyl group or pyrrolyl group (hereinafter referred to as a liquid crystal monomer (II)) that is unsubstituted or substituted, and X is phenyl. A monomer that is a group (hereinafter referred to as liquid crystal monomer (III)) can be particularly preferably used.

ここで、前記式（IV）における、Ｒ^１、Ｒ^２、Ｒ^３、Ｒ^４、Ｒ^５、Ｒ^６、Ａ^１及びＡ^２は、それぞれ前記式（Ｉ）に示すものと同じである。 There are no particular restrictions on the method for producing the liquid crystal monomer (I), but it can be obtained, for example, by a Sonogashira reaction between a monomer represented by the following formula (IV) (hereinafter referred to as liquid crystal monomer (IV)) and phenylacetylene. it can.

Here, R ¹ , R ² , R ³ , R ⁴ , R ⁵ , R ⁶ , A ¹ and A ² in the formula (IV) are the same as those shown in the formula (I).

ここで、前記式（Ｖ）における、Ｒ^１、Ｒ^３及びＡ^１は、それぞれ前記式（Ｉ）に示すものと同じである。 In addition, the liquid crystal monomer (IV) is obtained by, for example, an esterification reaction between 1 equivalent of bromoterephthalic acid and 2 equivalents of a phenolic compound represented by the following formula (V) (hereinafter referred to as phenol (V)). Obtainable.

Here, R ¹ , R ³ and A ¹ in the formula (V) are the same as those shown in the formula (I).

  In the esterification reaction, the target product can be easily synthesized by activating the bromoterephthalic acid with acid chloride or phosphorus pentachloride and reacting it with phenol (V). It is also possible to directly react bromoterephthalic acid with phenol (V) using a condensing agent such as DCC (dicyclohexylcarbodiimide).

The birefringence (Δn) at a wavelength of 589 nm of the polymerizable liquid crystal monomer (liquid crystal monomer (I), liquid crystal monomer (II) or liquid crystal monomer (III)) is preferably 0.01 to 0.10. More preferably, it is 0.03-0.09. Most preferably, it is 0.04-0.09. Most preferably, it is 0.04-0.09. Within the above range, even when a retardation film having a small retardation value is produced, a retardation film having good display uniformity can be produced. Incidentally, the birefringence index of the polymerizable liquid crystal monomer ([Delta] n), as described above, shows the difference between the refractive index of extraordinary ray (n _e) and the ordinary refractive index of the (n _o). It should be noted that the measurement of _{n e} and _{n o,} Shoichi al Industry Committee publication "Fundamentals and Applications of liquid crystal" Matsumoto (1991 edition) p. As described in No. 45, an Abbe refractometer (“DR-M4” manufactured by Atago Co., Ltd.) can be used.

The polymerizable liquid crystal monomer can have an average refractive index represented by the following formula (VI) of, for example, about 1.58 to 1.63.
_{(N e + 2n o) /} 3 ··· (VI)
Therefore, when compared with a retardation film using a conventional liquid crystal monomer, there is an advantage that Δn can be reduced (uneven retardation value can be suppressed) while maintaining an average refractive index equal to or higher than that.

  As described above, the retardation film according to the present invention is a composition containing a polymerizable liquid crystal monomer having a specific structure (liquid crystal monomer (I), preferably liquid crystal monomer (II), more preferably liquid crystal monomer (III)). Is obtained by orienting and fixing on the substrate. More specifically, the retardation film according to this embodiment is obtained by applying a mixed solution of a composition containing a polymerizable liquid crystal monomer and a polymerization initiator and a solvent on a substrate and curing the mixture. can get.

  The compounding amount of the polymerizable liquid crystal monomer is preferably 35 to 99 parts by weight with respect to 100 parts by weight of the total solid content of the mixed solution. More preferably, it is 40-99 weight part. More preferably, it is 45-99 weight part.

  The polymerization initiator is used to increase the crosslinking reaction rate and crosslinking reaction rate of the polymerizable liquid crystal monomer. The type of the polymerization initiator is not particularly limited, and is a photopolymerization initiator, a water-soluble azo polymerization initiator, an oil-soluble azo polymerization initiator, a polymer azo polymerization initiator, a photocationic initiator, or a radical photopolymerization initiator. The photopolymerization initiator is preferably used.

  There is no restriction | limiting in particular as a photoinitiator, The photoinitiator which consists of a single compound may be sufficient, and what mixed two or more types of different photoinitiators may be sufficient. Examples of the photopolymerization initiator include acetophenone compounds, benzoin compounds, benzophenone compounds, thioxanthone compounds, and the like. Also, for example, trade names “Irgacure 651”, “Irgacure 184”, “Darocur 1173”, “Irgacure 500”, “Irgacure 2959”, “Irgacure 907”, “Irgacure 369”, manufactured by Ciba Specialty Chemicals Co., Ltd. Photopolymerization initiators such as “Irgacure 819” and “Irgacure 784” may be used. Furthermore, the product names “Darocur 953” and “Darocur 1116” manufactured by Merck Co., Ltd., and the product names “Kayacure MBP”, “Kayacure CTX”, “Kayacure DITX”, “Kayacure DITX”, “Kayacure CTX” manufactured by Nippon Kayaku Co., Ltd. ”,“ Kayacure DETX ”,“ Kayacure RTX ”, and the like can also be used.

  In addition, an auxiliary agent may be added to the photopolymerization initiator in order to accelerate the polymerization reaction. Examples of the auxiliary agent include triethanolamine, methyldiethanolamine, triisopropanolamine, n-butylamine, N-methyldiethanolamine, diethylaminoethyl methacrylate, Michler's ketone, 4,4′-diethylaminophenone, ethyl 4-dimethylaminobenzoate, Examples thereof include amine compounds such as 4-dimethylaminobenzoic acid (nbutoxy) ethyl and 4-dimethylaminobenzoic acid isoamyl.

  The addition amount of the polymerization initiator is not particularly limited, but is preferably 0.5 to 20 parts by weight, more preferably 2 to 15 parts by weight with respect to 100 parts by weight of the polymerizable liquid crystal monomer. Is done. Moreover, it is preferable that the addition amount of an auxiliary agent is about 0.5 to 2 times the amount of the polymerization initiator (photopolymerization initiator).

  The solvent is used to uniformly disperse or dissolve the polymerizable liquid crystal monomer and the polymerization initiator. As such a solvent, the composition containing the polymerizable liquid crystal monomer and the polymerization initiator is excellent in solubility, and when the composition is applied to a substrate, the wettability of the substrate and the orientation of the composition If it does not cause the fall of this, there will be no restriction | limiting in particular.

  Specifically, as the solvent, for example, aromatic hydrocarbons such as benzene, toluene, xylene, methoxybenzene, 1,2-dimethoxybenzene, chloroform, dichloromethane, carbon tetrachloride, dichloroethane, tetrachloroethane, trichloroethylene, tetrachloroethylene Halogenated hydrocarbons such as chlorobenzene and orthodichlorobenzene, phenols such as phenol and parachlorophenol, ethers such as diethyl ether, dibutyl ether, tetrahydrofuran, anisole, dioxane, tetrahydrofuran, acetone, methyl isobutyl ketone, methyl ethyl ketone, cyclohexanone Cyclopentanone, 2-pentanone, 3-pentanone, 2-hexanone, 3-hexanone, 2-heptanone, 3-heptanone, Ketones such as heptanone, 2,6-dimethyl-4-heptanone, 2-pyrrolidone, N-methyl-2-pyrrolidone, n-butanol, 2-butanol, cyclohexanol, isopropyl alcohol, t-butyl alcohol, glycerin, Ethylene glycol, triethylene glycol, ethylene glycol monomethyl ether, diethylene glycol dimethyl ether, propylene glycol, dipropylene glycol, alcohols such as 2-methyl-2,4-pentanediol, amides such as dimethylformamide, dimethylacetamide, acetonitrile, butyronitrile Nitriles such as, cellosolves such as methyl cellosolve and methyl cellosolve, and esters such as ethyl acetate, butyl acetate and methyl lactate can be used. In addition, methylene chloride, carbon disulfide, ethyl cellosolve, butyl cellosolve, and the like can be given as examples of the solvent, but are not limited thereto.

  In addition, cyclopentanone, cyclohexanone, methyl isobutyl ketone, methyl ethyl ketone, tetrahydrofuran, toluene, or ethyl acetate is used as the solvent in that the composition can be sufficiently dissolved without substantially eroding the substrate. It is preferable to use it.

  The solvent may be used alone or in combination of two or more arbitrary solvents in order to improve the smoothness of the retardation film. The total solid content concentration of the mixed solution varies depending on solubility, coating viscosity, wettability on the substrate, thickness after coating, etc., but in order to obtain a highly smooth retardation film, the solvent is 100 weight. The solid content is preferably dissolved in an amount of 2 to 100 parts by weight, more preferably 20 to 80 parts by weight, particularly preferably 30 to 60 parts by weight.

  In addition, when the wettability of the mixed solution with respect to the substrate is poor or when the surface uniformity of the retardation film is poor, various leveling agents may be added to the mixed solution in order to improve these. Is possible. As the type of the leveling agent, various compounds such as silicone, fluorine, polyether, acrylic acid copolymer and titanate can be used. The amount of these leveling agents to be added is not particularly limited. However, in order to improve the smoothness and not disturb the orientation of the composition containing the polymerizable liquid crystal monomer and the polymerization initiator, The added amount is 0.005 to 0.20 parts by weight, more preferably 0.010 to 0.10 parts by weight, per 100 parts by weight.

  In addition to the polymerizable liquid crystal monomer, the polymerization initiator, and the solvent, a polymerizable chiral agent and a vertical alignment treatment agent can be added to the mixed solution. Such a polymerizable chiral agent and a vertical alignment treatment agent are used to change the alignment state of the polymerizable liquid crystal monomer.

  The polymerizable chiral agent can develop a cholesteric liquid crystal phase. The cholesteric liquid crystal phase refers to a liquid crystal phase in which a uniform helical structure of the polymerizable liquid crystal monomer is formed. Normally, the cholesteric liquid crystal phase can be regarded as a pseudo layer structure, and the orientation vector of the liquid crystal molecules changes periodically with the helical pitch as a repeating unit, so the helical axis (helical axis) is the normal to the substrate. When parallel to the direction, the refractive index in the thickness direction is smaller than the refractive index in the film plane.

  In addition to the polymerizable liquid crystal monomer, the polymerization initiator and the solvent, the retardation film prepared from the mixed solution containing the polymerizable chiral agent has a refractive index in the thickness direction that is smaller than the refractive index in the film plane. Therefore, when the two main refractive indexes in the film plane are nx and ny, and the refractive index in the thickness direction is nz, it is used as a retardation film (so-called negative C plate) having a characteristic of nx≈ny> nz. it can. Such a negative C plate is disposed between the liquid crystal cell and the polarizing plate, and can be suitably used to improve the viewing angle characteristics from an oblique direction.

  The polymerizable chiral agent has at least one polymerizable functional group and a functional group (optically active group) having an asymmetric carbon atom in the molecular structure, and the orientation of the polymerizable nematic liquid crystalline compound There is no particular limitation as long as it does not disturb. Examples of the polymerizable functional group include an acryloyl group, a methacryloyl group, an epoxy group, and a vinyl ether group. Among these, an acryloyl group or a methacryloyl group is preferable. The polymerizable chiral agent may be liquid crystalline or not, but preferably exhibits a cholesteric liquid crystal phase.

  The addition amount of the polymerizable chiral agent is preferably 4.5 to 25 parts by weight with respect to 100 parts by weight of the total solid content in the mixed solution. More preferably, 4.5 to 20 parts by weight, still more preferably 4.5 to 15 parts by weight is added.

  Examples of the vertical alignment treatment agent include homeotropic alignment side chain type liquid crystal polymers described in JP-A No. 2003-149441. Such homeotropic alignment side chain type liquid crystal polymer is used for vertically aligning the polymerizable liquid crystal monomer in the normal direction of the film (also referred to as homeotropic alignment).

  In addition to the polymerizable liquid crystal monomer, the polymerization initiator and the solvent, the retardation film produced from the mixed solution containing the vertical alignment treatment agent has a refractive index in the thickness direction larger than the refractive index in the film plane. Therefore, when the two main refractive indexes in the film plane are nx and ny, and the refractive index in the thickness direction is nz, it is used as a retardation film (so-called positive C plate) having a characteristic of nz> nx≈ny. it can. Such a positive C plate is disposed between the liquid crystal cell and the polarizing plate, and can be suitably used to improve the viewing angle characteristics from an oblique direction.

  The addition amount of the vertical alignment treatment agent is preferably 1 to 25 parts by weight with respect to 100 parts by weight of the total solid content in the mixed solution. More preferably 2 to 20 parts by weight, still more preferably 3 to 15 parts by weight are added.

  The base material is used for uniformly developing a polymerizable liquid crystal monomer and a polymerization initiator and then obtaining a uniform alignment state. Examples of the material for forming such a base material include polyester resins such as polyethylene terephthalate and polyethylene naphthalate, cellulose resins such as diacetyl cellulose and triacetyl cellulose, acrylic resins such as polymethyl methacrylate, polystyrene, acrylonitrile, Styrene copolymer, styrene resin, acrylonitrile / styrene resin, acrylonitrile / butadiene / styrene resin, acrylonitrile / ethylene / styrene resin, styrene / maleimide copolymer, styrene resin such as styrene / maleic anhydride copolymer, polycarbonate Examples thereof include resins. In addition, cycloolefin resin, norbornene resin, polyolefin resin such as polyethylene, polypropylene, ethylene / propylene copolymer, vinyl chloride resin, amide resin such as nylon and aromatic polyamide, aromatic polyimide, polyimide amide, etc. Imide resins, sulfone resins, polyether sulfone resins, polyether ether ketone resins, polyphenylene sulfide resins, vinyl alcohol resins, vinylidene chloride resins, vinyl butyral resins, arylate resins, polyoxymethylene resins Examples thereof include resins and epoxy resins. Moreover, the polymer film base material etc. which consist of the said resin blend etc. can also be mentioned. Furthermore, metal substrates such as aluminum, iron and copper, glass substrates such as blue plate glass, alkali glass, alkali-free glass, borosilicate glass, flint glass and quartz glass, various substrates such as ceramic substrates, silicon wafers Various semiconductor substrates such as can also be mentioned.

  In addition, it is particularly preferable to use polyethylene terephthalate as the base material in that it is not eroded by the solvent and can induce uniform orientation of the composition.

  Moreover, as said base material, a commercially available polymer film and a conventionally well-known 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 Zeon Corporation, the product name “Arton” manufactured by JSR Corporation, and the like can be mentioned. Further, a polymer film containing an alternating copolymer composed of isobutylene and N-methylmaleimide and an acrylonitrile / styrene copolymer as described in JP-A No. 2001-343529 can also be used. The base material may be provided with another film on the surface, for example, an organic film (also referred to as an alignment film) such as a polyimide film, a polyamide film, or a polyvinyl alcohol film, or an obliquely deposited film of silicon oxide. . Further, when the substrate is a polymer film, it may be subjected to stretching treatment or shrinkage treatment to give anisotropy in the film plane.

  Examples of the method for orienting the composition on the substrate include a rubbing method, oblique vapor deposition method, microgroove method, stretched polymer film method, LB (Langmuir-Blodget) film method, transfer method, and light irradiation. The method (photoisomerization, photopolymerization, photolysis, etc.), the peeling method, etc. can be mentioned. Alternatively, an orientation treatment method using a magnetic field, an electric field, shear stress, or the like may be used. In terms of the ease of the manufacturing process, it is preferable to use a rubbing method or a photo-alignment method as the alignment treatment method.

  The alignment film used in the rubbing method is not particularly limited, but the wettability of the mixed solution is excellent, and a composition containing a polymerizable liquid crystal monomer, a polymerizable chiral agent and a polymerization initiator is aligned in a specific direction. Those that can be used are preferred. As such an alignment film, specifically, for example, polyamide, polyimide, lecithin, silica, polyvinyl alcohol, ester-modified polyvinyl alcohol, a polymer in which the degree of saponification of polyvinyl acetate is adjusted, a silane coupling agent, or the like is applied. An alignment film formed by the above can be mentioned. Further, the surface of the base material may be subjected to orientation treatment by a rubbing method as it is.

  Although there is no restriction | limiting in particular as an alignment film used for the said photo-alignment method, For example, an isomerization polymer, a photodimerization polymer, and a photodecomposition polymer can be used. These polymers can induce orientation of a composition containing a polymerizable liquid crystal monomer, a polymerizable chiral agent, and a polymerization initiator by irradiation with radiation. The radiation used may be any of ultraviolet rays, visible rays, and infrared rays. These radiations may be polarized or non-polarized. Preferable photoalignable materials include cinnamic acid derivatives as described in US Pat. No. 6,160,597. Such photo-alignable materials can be aligned and cross-linked by linearly polarized ultraviolet light.

  There is no limitation in particular about the coating method to the base material of the said mixed solution, A conventionally well-known coating method can be used. For example, the mixed solution may be developed into a thin layer by a spin coating method, a roll coating method, a flow coating method, a printing method, a dip coating method, a casting film forming method, a bar coating method, a gravure printing method, or the like. The coating thickness of the mixed solution is usually 2 to 300 μm, more preferably 2 to 200 μm, and particularly preferably 2 to 50 μm. If the thickness is within the above range, a product excellent in optical uniformity can be produced.

  The substrate coated with the mixed solution may be subjected to a drying treatment as necessary before fixing the composition on the substrate. Although there is no restriction | limiting in particular as temperature in drying processing (it is also called drying temperature), The preferable drying temperature (Tt) is a crystal phase (or glass phase) -liquid crystal phase of the composition containing a polymerizable liquid crystal monomer and a polymerization initiator. It is not lower than the transition temperature (referred to as Tg) and lower than the liquid crystal phase-isotropic phase transition temperature (referred to as Ti). Moreover, it is preferable to set it as the glass transition temperature or less of a base material. More preferably, Tg + 2 ° C. ≦ Tt <Ti, and most preferably Tg + 3 ° C. ≦ Tt <Ti. If it is said temperature range, a highly uniform retardation film can be produced. The drying time is not particularly limited, but in order to obtain a retardation film having good optical uniformity, it is, for example, 30 seconds to 20 minutes, preferably 1 to 15 minutes, more preferably 1 -10 minutes.

  The specific method for keeping the drying temperature constant is not particularly limited, but heaters using hot air, microwaves, far infrared rays, etc., rolls heated for temperature adjustment, heat pipe rolls, metal belts, etc. The well-known heating method and temperature control method using can be mentioned.

  When the variation in the drying temperature is large, the unevenness of the thickness of the coated surface becomes large, resulting in variation in the retardation value of the finally obtained retardation film. Accordingly, it is preferable that the temperature variation in the in-plane direction of the retardation film is as small as possible, and it is desirable that the temperature variation in the in-plane direction is within a range of ± 1 ° C.

  Examples of the fixing method of the composition include a method by heating and a method by irradiation with radiation. However, in the case of adopting a method by heating, it is preferable to adopt a method by irradiation of radiation, since the polymerizable liquid crystal monomer may cause an isotropic phase transition to cause alignment failure. Radiation irradiation is used to fix the alignment state of the polymerizable liquid crystal monomer by causing the polymerizable liquid crystal monomer to crosslink and cure.

  Although there is no restriction | limiting in particular as a kind of the said radiation, A gamma ray, an electron beam, visible light, an ultraviolet-ray etc. can be mentioned. Preferably, ultraviolet irradiation is used because it is easy to manufacture. The wavelength of the light source in ultraviolet irradiation is determined according to the wavelength region in which the photochemically reactive compound used has optical absorption. In general, the thickness is preferably 190 nm to 400 nm. More preferably, it is 250 nm to 380 nm. As the light source having such wavelength characteristics, an ultrahigh pressure mercury lamp, a flash mercury lamp, a high pressure mercury lamp, a low pressure mercury lamp, a deep UV lamp, a xenon lamp, a xenon flash lamp or a metal halide lamp is preferably used. The ultraviolet light emitted from the light source may be non-polarized light or polarized light.

  There is no restriction | limiting in particular as a position of the light source in the said radiation irradiation, You may arrange | position to the side by which the said mixed solution is coated, and may arrange | position to the opposite base material side. Moreover, there is no restriction | limiting in particular as atmosphere in air | atmosphere in the said radiation irradiation, Air atmosphere, nitrogen atmosphere, argon atmosphere, etc. can be used.

Although there is no restriction | limiting in particular as irradiation amount of an ultraviolet-ray, Preferably, it is 100-1500 mJ / cm < ² >. More preferably, it is set to 100 to 800 mJ / cm ² . If it is the irradiation amount of the said range, a polymeric liquid crystal monomer will fully harden | cure and it can fix on a base material.

  The temperature of the atmosphere at the time of radiation irradiation (also referred to as irradiation temperature) is not particularly limited, but it is preferable to perform radiation irradiation while maintaining the temperature within a range of 30 to 100 ° C. in order to fix a uniform alignment state.

  The range of the thickness of the composition after being oriented and fixed on the base material in the retardation film produced as described above (hereinafter referred to as an optical thin film as appropriate) is the birefringence of the polymerizable liquid crystal monomer. Although it can be selected according to (Δn) and the phase difference value to be designed, it is usually 1 to 10 μm, more preferably 1.2 to 8 μm, and particularly preferably 1.3 to 6 μm. Most preferably, it is 1.5-5 micrometers. If thickness is 1-10 micrometers, it will become a phase difference film excellent in optical uniformity.

  The light transmittance of the retardation film according to the present invention is preferably 80% or more at a wavelength of 590 nm, more preferably 85% or more, and further preferably 90% or more.

In the retardation film according to the present invention, the in-plane retardation value Re (590) measured with light having a wavelength of 590 nm satisfies the following formula (1) in order to improve the display characteristics of the liquid crystal panel. It is preferable to configure as described above.
80 nm ≦ Re (590) ≦ 800 nm (1)
Here, Re (590) = (nx−ny) × d, where nx is the refractive index in the slow axis direction of the retardation film (the direction in which the refractive index in the retardation film is maximized), and ny is The refractive index in the fast axis direction of the retardation film, and d [nm] means the thickness of the retardation film.

  In particular, when the retardation film according to the present invention is used as a λ / 2 plate (half-wave plate), it is preferable that 200 nm <Re (590) ≦ 350 nm. More preferably, 240 nm <Re (590) ≦ 300 nm, particularly preferably 260 nm <Re (590) ≦ 280 nm, and most preferably 265 nm <Re (590) ≦ 275 nm. When the retardation film according to the present invention is used as a λ / 4 plate (¼ wavelength plate), it is preferable that 80 nm <Re (590) ≦ 200 nm. More preferably, 120 nm <Re (590) ≦ 160 nm, particularly preferably 130 nm <Re (590) ≦ 150 nm, and most preferably 135 nm <Re (590) ≦ 145 nm.

  The variation of the phase difference value Re (590) is preferably within ± 5.0 nm, more preferably within ± 4.0 nm, and particularly preferably within ± 3.0 nm.

As the wavelength dispersion characteristic of the retardation film, D ₁ (Re) value and D ₂ (Re) value calculated by the following formulas (2) and (3) are 0.818 ≦ D ₁ (Re) ≦ It is preferable that 1.080, 0.961 ≦ D ₂ (Re) ≦ 1.182. The range of D ₁ (Re) and D ₂ (Re) values is more preferably 1.000 ≦ D ₁ (Re) ≦ 1.080, 0.965 ≦ D ₂ (Re) ≦ 1.000, particularly preferably 1.010 ≦ D ₁ (Re) ≦ 1.070, 0.968 ≦ D ₂ (Re) ≦ 0.990. Most preferably, 1.030 ≦ D ₁ (Re) ≦ 1.040 and 0.970 ≦ D ₂ (Re) ≦ 0.985. The wavelength dispersion characteristic of such a retardation film is such that the smaller the value in the above range, the smaller the wavelength dependency of the retardation value when used in applications such as a λ / 4 plate and a λ / 2 plate. The display characteristics of the panel can be further improved.
D ₁ (Re) = Re (450) / Re (550) (2)
D ₂ (Re) = Re (650) / Re (550) (3)
Here, Re (450), Re (550), and Re (650) are retardation values in the film plane for light having wavelengths of 450 nm, 550 nm, and 650 nm, respectively.

  The present invention is also provided as an optical film in which the retardation film described above is laminated. Hereinafter, an optical film obtained by laminating a retardation film according to the present invention and another retardation film will be mainly described as an example.

  In the optical film according to the present invention, the above-described retardation film according to the present invention and another retardation film are laminated with an adhesive, an adhesive, or the like. Examples of the other retardation film include polyester resins such as polyethylene terephthalate and polyethylene naphthalate, cellulose resins such as diacetyl cellulose and triacetyl cellulose, acrylic resins such as polymethyl methacrylate, polystyrene, acrylonitrile and styrene. Polymers, styrene resins, acrylonitrile / styrene resins, acrylonitrile / butadiene / styrene resins, acrylonitrile / ethylene / styrene resins, styrene / maleimide copolymers, styrene resins such as styrene / maleic anhydride copolymers, polycarbonate resins, etc. Can be mentioned. In addition, cycloolefin resin, norbornene resin, polyolefin resin such as polyethylene, polypropylene, ethylene / propylene copolymer, vinyl chloride resin, amide resin such as nylon and aromatic polyamide, aromatic polyimide, polyimide amide, etc. Imide resins, sulfone resins, polyether sulfone resins, polyether ether ketone resins, polyphenylene sulfide resins, vinyl alcohol resins, vinylidene chloride resins, vinyl butyral resins, arylate resins, polyoxymethylene resins Examples include a film in which birefringence characteristics are imparted to a polymer film made of a resin, an epoxy resin or a blend of the above resins, or a film obtained by applying a mixed solution containing a liquid crystalline compound on a substrate and then drying and curing the film. You can also. The birefringence characteristic may spontaneously occur when the polymer film is formed, or can be imparted by stretching the polymer film uniaxially or biaxially.

  The birefringence characteristics of the other retardation film are not particularly limited. For example, when used in a liquid crystal display device of IPS mode, VA mode, and OCB mode, Re (590) = 80 to 140 nm (Rth ( 590) / Re (590) = 0.9 to 1.3) uniaxial retardation film, Re (590) = 0-5 nm and Rth (590) = 90-400 nm negative uniaxial retardation film In addition to a uniaxial inclined alignment retardation film whose optical axis is inclined at 10 to 80 ° from the normal line of the film and the substrate, Re (590) = 30 to 60 nm (Rth (590) / Re (590) = 2.0 -6.0) biaxial retardation film, Re (590) = 100-300 nm (Rth (590) / Re (590) = 0.2-0.8) biaxial retardation film, disco Tic liquid crystal molecules Hybrid orientation phase difference film rod-like liquid crystal molecules are gradually tilted to the normal of the substrate is preferably used. The Rth (590) means a retardation value in the film thickness direction with respect to light having a wavelength of 590 nm.

  When the uniaxial retardation film or the biaxial retardation film is used (laminated) together with the retardation film according to the present invention, further improvement in viewing angle characteristics of the liquid crystal display device can be expected. As the optical film according to the present invention, two or more retardation films according to the present invention may be laminated at an arbitrary angle, or two or more retardation films according to the present invention may be laminated. A combination of these retardation films may also be used.

  Moreover, this invention is provided also as a polarizing plate which has arrange | positioned the retardation film or optical film which concerns on this invention mentioned above at least on the single side | surface side of a polarizer.

  The polarizing plate which concerns on this invention can be obtained by laminating | stacking the said retardation film or optical film with a polarizer (or polarizing plate) using an adhesive agent or an adhesive. The polarizing plates are usually arranged on both sides of the liquid crystal cell so that the absorption axes of the polarizing plates are substantially orthogonal to each other. The polarizing plate is usually provided with a transparent protective film on one side or both sides of the polarizer. When providing a transparent protective film on both surfaces of a polarizer, each transparent protective film may be formed from the same material, and may be formed from a different material.

  The polarizer is not particularly limited, and various types can be used. For example, as a polarizer, a dichroic substance such as iodine or a dichroic dye as a hydrophilic polymer film such as a polyvinyl alcohol film, a partially formalized polyvinyl alcohol film or an ethylene / vinyl acetate copolymer partially saponified film. And a polyene-based oriented film such as a uniaxially stretched film and a dehydrated product of polyvinyl alcohol or a dehydrochlorinated product of polyvinyl chloride. Among these, a polarizer made of a dichroic substance such as a polyvinyl alcohol film and iodine is preferably used because it has a high polarization dichroic ratio. The thickness of the polarizer is not particularly limited, but is generally about 5 to 80 μm.

  A uniaxially stretched polarizer by adsorbing iodine to a polyvinyl alcohol film is produced by, for example, dyeing a polyvinyl alcohol film by immersing it in an aqueous solution of iodine and stretching it 3 to 7 times the original length. can do. If necessary, it can be immersed in an aqueous solution of potassium iodide containing 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.

  By washing the polyvinyl alcohol film with water, it is possible to clean the surface of the polyvinyl alcohol film and the anti-blocking agent, and also to prevent the dyeing from becoming uneven by swelling the polyvinyl alcohol film. is there. Stretching may be performed after dyeing with iodine, or may be performed while dyeing. It is also possible to dye 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 provided on one side or both sides of the polarizer, those having excellent transparency, mechanical strength, thermal stability, moisture shielding property, retardation value stability and the like are preferable. Examples of the material for forming such a transparent protective film include polyester resins such as polyethylene terephthalate and polyethylene naphthalate, cellulose resins such as diacetyl cellulose and triacetyl cellulose, acrylic resins such as polymethyl methacrylate, polystyrene, and the like. Acrylonitrile / styrene copolymer, styrene resin, acrylonitrile / styrene resin, acrylonitrile / butadiene / styrene resin, acrylonitrile / ethylene / styrene resin, styrene / maleimide copolymer, styrene resin such as styrene / maleic anhydride copolymer, A polycarbonate-type resin etc. can be mentioned. In addition, cycloolefin resin, norbornene resin, polyolefin resin such as polyethylene, polypropylene, ethylene / propylene copolymer, vinyl chloride resin, amide resin such as nylon and aromatic polyamide, aromatic polyimide, polyimide amide, etc. Imide resins, sulfone resins, polyether sulfone resins, polyether ether ketone resins, polyphenylene sulfide resins, vinyl alcohol resins, vinylidene chloride resins, vinyl butyral resins, arylate resins, polyoxymethylene resins Resins, epoxy resins and the like can also be used. Moreover, the polymer film etc. which consist of the said resin blend etc. can be mentioned as an example of resin which forms the said transparent protective film. The transparent protective film can also be formed as a cured layer of thermosetting or ultraviolet curable resin such as acrylic, urethane, acrylurethane, epoxy, or silicone.

  Further, (A) a thermoplastic resin having a substituted and / or unsubstituted imide group in the side chain as described in JP-A-2001-343529, and (B) a substituted and / or unsubstituted phenyl in the side chain. In addition, a resin composition containing a thermoplastic resin having a nitrile group can also be used. Specific examples include a polymer film containing an alternating copolymer composed of isobutylene and N-methylmaleimide and an acrylonitrile / styrene copolymer.

  From the viewpoint of polarization characteristics and durability, it is preferable to use a cellulose resin such as triacetyl cellulose or a norbornene resin as the transparent protective film. Specifically, the product name “Fujitac” manufactured by Fuji Photo Film Co., Ltd., the product name “ZEONOR” manufactured by ZEON CORPORATION, the product name “ARTON” manufactured by JSR Corporation, and the like can be mentioned. .

  The thickness of the transparent protective film can be determined as appropriate, but generally it is preferably 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, Most preferably, it is 10-150 micrometers. If it is said range, a polarizer can 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 transparent protective film, since the retardation value in the film plane and the retardation value in the thickness direction may affect the viewing angle characteristics of the liquid crystal display device, the one having an optimized retardation value may be used. preferable. However, the transparent protective film for which optimization of the retardation value is desired is a transparent protective film laminated on the surface of the polarizer close to the liquid crystal cell, and is transparent on the surface of the polarizer far from the liquid crystal cell. The protective film is not limited to this because it does not change the optical characteristics of the liquid crystal display device.

  The retardation value of the transparent protective film is preferably such that the in-plane retardation value Re (590) is 0 to 10 nm. More preferably, it is 0-5 nm, More preferably, it is 0-1 nm. The retardation value Rth (590) in the film thickness direction is preferably 0 nm to 200 nm. More preferably, it is 0-60 nm, More preferably, it is 0 nm-30 nm.

  The method for laminating the transparent protective film with the polarizer is not particularly limited. For example, an adhesive made of an acrylic polymer or a vinyl alcohol polymer, boric acid or borax, glutaraldehyde melamine or oxalic acid. It can be laminated via an adhesive or the like comprising at least a water-soluble crosslinking agent of a vinyl alcohol polymer. As a result, it is difficult to peel off due to the influence of humidity and heat, and the light transmittance and the degree of polarization can be improved. As the adhesive, a polyvinyl alcohol-based adhesive is preferably used from the viewpoint of excellent adhesiveness with polyvir alcohol, which is a raw material of a polarizer.

  As a pressure-sensitive adhesive when laminating a polymer film containing the norbornene-based resin as a transparent protective film with a polarizer, it is excellent in transparency, has small birefringence, etc., and can sufficiently exhibit adhesive force even when used as a thin layer. Those are preferred. As such an adhesive, for example, an adhesive for dry lamination in which a polyurethane resin solution and a polyisocyanate resin solution are mixed, a styrene butadiene rubber adhesive, an epoxy two-component curable adhesive (an epoxy resin and a polythiol adhesive) For example, a two-part liquid or an epoxy resin / polyamide two-part liquid) can be used. In particular, a solvent-type adhesive or an epoxy two-component curable adhesive is preferably transparent. Some adhesives can improve the adhesive force by using an appropriate adhesive primer. When such an adhesive is used, it is preferable to use an adhesive primer.

  The adhesive primer is not particularly limited as long as it can improve adhesiveness.For example, in the same molecule, a reactive functional group such as amino group, vinyl group, epoxy group, mercapto group, chloro group and the like. Silane coupling agent having hydrolyzable alkoxysilyl group, titanate coupling agent having hydrolyzable hydrophilic group and organic functional group containing titanium in the same molecule, aluminum in the same molecule Organic reactivity of so-called coupling agents such as aluminate coupling agents having hydrolyzable hydrophilic groups and organic functional groups, epoxy resins, isocyanate resins, urethane resins, ester urethane resins, etc. A resin having a group can be used. Among these, it is preferable that a silane coupling agent is contained from the viewpoint of easy industrial handling.

  The polarizing plate according to the present invention is preferably provided with a layer of an adhesive or a pressure-sensitive adhesive on both sides or one side in order to facilitate lamination to the liquid crystal cell.

  The adhesive or pressure-sensitive adhesive is not particularly limited, but for example, acrylic polymer, silicone polymer, polyester, polyurethane, polyamide, polyvinyl ether, vinyl acetate / vinyl chloride copolymer, modified polyolefin, epoxy-based, fluorine-based, natural A polymer having a base polymer such as rubber or synthetic rubber such as synthetic rubber can be appropriately selected and used. In particular, an acrylic pressure-sensitive adhesive is preferably used because it is excellent in optical transparency, exhibits appropriate wettability, cohesiveness, and adhesive pressure-sensitive adhesive properties, and is excellent in weather resistance and heat resistance.

  The adhesive or pressure-sensitive adhesive can contain a crosslinking agent according to the base polymer. In addition, for the adhesive, if necessary, for example, natural and synthetic resins, glass fibers and glass beads, fillers made of metal powder and other inorganic powders, pigments, colorants, antioxidants, etc. These appropriate additives can also be blended. Moreover, it can also be set as the adhesive layer which contains a transparent fine particle and shows light diffusibility.

  The transparent fine particles may have conductivity such as silica, calcium oxide, alumina, titania, zirconia, tin oxide, indium oxide, cadmium oxide, and antimony oxide having an average particle size of 0.5 to 20 μm. One kind or two or more kinds of appropriate fine particles such as certain inorganic fine particles and crosslinked or uncrosslinked organic fine particles made of a suitable polymer such as polymethyl methacrylate and polyureta can be used.

  The adhesive or pressure-sensitive adhesive is usually used as an adhesive solution having a solid content concentration of about 10 to 50% by weight in which a base polymer or a composition thereof is dissolved or dispersed in a solvent. As the solvent, an organic solvent such as toluene or ethyl acetate or a solvent such as water can be appropriately selected and used.

  The adhesive or pressure-sensitive adhesive can be provided on one or both sides of the polarizing plate as a laminate of different compositions or types. The thickness of the adhesive or pressure-sensitive adhesive can be appropriately determined according to the purpose of use and adhesive force, and is generally 1 to 500 μm, preferably 5 to 200 μm, and particularly preferably 10 to 100 μm.

  The exposed surface of the adhesive layer or pressure-sensitive adhesive layer is protected by temporarily attaching a release paper or a release film (also referred to as a separator) for the purpose of preventing contamination until it is put to practical use. Is preferred. Thereby, in a usual handling state, it can prevent contacting an adhesive bond layer or an adhesive layer. Examples of the separator include, for example, plastic films, rubber sheets, paper, cloth, non-woven fabrics, nets, foam sheets, metal foils, and appropriate thin leaves such as laminates thereof, if necessary, silicone-based, long mirror alkyl-based An appropriate material according to the prior art, such as those coated with an appropriate release agent such as fluorine-based or 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 excellent in hardness, sliding properties, etc. by an appropriate ultraviolet curable resin such as acrylic or silicone. It is formed on the surface of the transparent protective film. 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 hindering the viewing of the light transmitted through the polarizing plate. For example, the surface is roughened by sandblasting or embossing. A fine concavo-convex structure (antiglare layer) is imparted to the surface of the transparent protective film by an appropriate method such as a compounding method of transparent fine particles. The anti-glare 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, other optical members that can be used in combination with the retardation film, optical film, or polarizing plate according to 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 anti-sticking process, and the spreading | diffusion process (it is also called an anti-glare process) as a separate optical film is mentioned. Moreover, a reflective polarizing plate or a semi-transmissive polarizing plate in which a reflecting plate or a semi-transmissive reflecting plate is further laminated on an elliptical polarizing plate or a circular polarizing plate can be given. Moreover, the reflection type polarizing plate, the reflection type elliptical polarizing plate which combined the said transflective type polarizing plate, and retardation film, a semi-transmission type elliptical polarizing plate, etc. may be sufficient. Further, when the retardation film, optical film or polarizing plate according to the present invention is used in 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, a liquid crystal display device with high display characteristics can be obtained by using together with D-BEF manufactured by Sumitomo 3M Co., Ltd.

  The optical film and polarizing plate according to the present invention can be formed by sequentially laminating, for example, in the manufacturing process of the liquid crystal display device. However, it is better to previously laminate the quality and the laminating workability. It is preferable because the manufacturing efficiency of a liquid crystal display device and the like can be improved.

  The retardation film, optical film and polarizing plate according to the present invention described above, and a liquid crystal panel including these and a liquid crystal cell are suitably used for a liquid crystal display device, an organic electroluminescence (organic EL) display, and the like. be able to.

  The type of the liquid crystal display device is not particularly limited, and can be used for any type of transmissive type, reflective type, and reflective transflective type. Examples of the liquid crystal cell 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). Examples include various liquid crystal cells such as mode, bend nematic (OCB) mode, ferroelectric liquid crystal (SSFLC) mode, and antiferroelectric liquid crystal (AFLC) mode. Among these, the retardation film, the optical film and the polarizing plate according to the present invention are particularly preferably used for a liquid crystal cell of a TN mode, a VA mode, an IPS mode or an OCB mode.

  The twisted nematic (TN) mode liquid crystal cell is one in which a nematic liquid crystal having positive dielectric anisotropy is sandwiched between two substrates, and the liquid crystal molecules are aligned by surface alignment treatment of the glass substrate. The one that has been twisted. Specific examples thereof 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 is vertical when no voltage is applied. An aligned liquid crystal cell. Specific examples include liquid crystal cells described in JP-A-62-210423 and JP-A-4-153621. Further, as described in JP-A-11-258605, the VA mode liquid crystal cell has a structure in which a slit is provided in a pixel or a projection is formed on the surface in order to enlarge a viewing angle. A multi-domain MVA mode liquid crystal cell may be used by using a material. Further, as described in Japanese Patent Application Laid-Open No. 10-123576, a VATN mode 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. A liquid crystal cell may be used.

  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 an ECB (Electrically Controlled Birefringence) effect. A liquid crystal which responds to a nematic liquid crystal that is homogeneously aligned in the absence of an electric field (also called a transverse electric field) parallel to the substrate. Specifically, Techno Times publication “Monthly Display July issue”, pages 83-88 (1997 version) and Japanese Liquid Crystal Society publication “Liquid Crystal vol.2 No.4”, pages 303-316 (1998 version). As described, when the major axis of the liquid crystal molecules and the polarization axis of the incident-side polarizing plate are aligned and the upper and lower polarizing plates are arranged perpendicularly, the display becomes completely black without an electric field, In a certain state, the liquid crystal molecules can obtain transmittance according to the rotation angle by rotating while maintaining a state parallel to the substrate.

  The liquid crystal cell of the above-mentioned bend nematic (OCB: Optically Compensated Bend or Optically Compensated Birefringnence) mode uses a voltage controlled birefringence (ECB) effect, and nematic with positive dielectric anisotropy between transparent electrodes. This means 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, optical film or polarizing plate according to the present invention for such various liquid crystal cells, the contrast, hue and viewing angle characteristics can be improved, and the function can be maintained for a long time. Can do.

  Hereinafter, although an example and a comparative example are shown and the present invention is explained still in detail, the present invention is not limited only to these examples.

The measurement conditions for each characteristic are as shown below.
(1) Liquid crystal temperature range The liquid crystal temperature range was measured by using a polarizing microscope (OLYMPUS BX50) equipped with a hot stage (METTLER TOLEDO FP82HT) and observing at a heating / cooling rate of 10 ° C / min. More specifically, the lower limit of the liquid crystal temperature range is determined by the crystal phase-liquid crystal phase transition temperature (Tm), and the upper limit is determined by the liquid crystal phase-isotropic phase transition temperature (Ti). It measured by observing with the said polarizing microscope (Two polarizers are arrange | positioning crossed Nicols), arrange | positioning the liquid crystal compound pinched | interposed with glass on the said hot stage, and raising / lowering temperature. The crystal phase-liquid crystal phase transition temperature (Tm) is a temperature at which a liquid crystal crystal dissolves (becomes fluid) under a polarizing microscope, and the liquid crystal phase-isotropic phase transition temperature (Ti) is a bright field. It is the temperature when turning from dark to dark.
(2) The refractive index difference Δn and the average refractive index Δn and the average refractive index were calculated based on the refractive index measured at room temperature with a wavelength of 589 nm using an Abbe refractometer.
(3) In-plane retardation value and wavelength dispersion characteristic The in-plane retardation value was measured at room temperature at a wavelength of 590 nm using a spectroscopic ellipsometer (M-220, manufactured by JASCO Corporation). The wavelength dispersion characteristic was calculated by measuring the in-plane retardation values at wavelengths of 450 nm, 550 nm, and 650 nm at room temperature using the above spectroscopic ellipsometer.
(4) Light transmittance The light transmittance was measured using an ultraviolet-visible spectrophotometer (V-560, manufactured by JASCO Corporation).

前記化学構造式１で示されるモノマー（５．００ｇ，６．５２ｍｍｏｌ）、フェニルアセチレン（０．８０ｇ，７．８３ｍｍｏｌ）、ＰｄＣｌ_２（ＰＰｈ_３）_２（０．２３ｇ，０．３３ｍｍｏｌ）、トリフェニルホスフィン（０．３４ｇ，１．３１ｍｍｏｌ）、ヨウ化銅（Ｉ）（０．２５ｇ、１．３１ｍｍｏｌ）、重合禁止剤としてＢＨＴを微量に含むＴＨＦ溶液（１０ｍｌ）にトリエチルアミン（１．８２ｍｌ）を加え、８０℃で１２時間攪拌した。反応終了後に１Ｎ塩酸を加え、ジクロロメタンで抽出した。有機層は、飽和食塩水で洗浄した後、硫酸マグネシウムで乾燥させた。和光純薬製「フロリジール７５〜１５０μｍ（１００〜２００ｍｅｓｈ）」のショートカラムを通した後、エバポレーションで溶媒を除き、イソプロピルアルコールから再結晶させることにより、前記化学構造式２で示される化合物が３．３２ｇ（６４％）得られた。 (Production Example 1)

Monomer (5.00 g, 6.52 mmol) represented by the chemical structural formula 1, phenylacetylene (0.80 g, 7.83 mmol), PdCl ₂ (PPh ₃ ) ₂ (0.23 g, 0.33 mmol), triphenyl Add triethylamine (1.82 ml) to a THF solution (10 ml) containing phosphine (0.34 g, 1.31 mmol), copper (I) iodide (0.25 g, 1.31 mmol) and BHT in a trace amount as a polymerization inhibitor. , And stirred at 80 ° C. for 12 hours. 1N hydrochloric acid was added after completion | finish of reaction, and the dichloromethane extracted. The organic layer was washed with saturated brine and dried over magnesium sulfate. After passing through a short column of “Florisil 75-150 μm (100-200 mesh)” manufactured by Wako Pure Chemical Industries, the solvent is removed by evaporation and recrystallized from isopropyl alcohol. .32 g (64%) was obtained.

The liquid crystal temperature range was as follows.
Liquid crystal temperature range (at elevated temperature): melting point 95 ° C
Liquid crystal temperature range (when temperature falls): 51-35 ° C

In addition, spectrum data of the compound represented by the chemical structural formula 2 are shown below.
Here, the measurement of ¹ H-NMR uses JEOL 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. ^The measurement of 13 C-NMR, the observation nucleus: @ 13 C, Frequency: except that the 100 ^MHz, measured under the same conditions as the measurement of 1 H-NMR. Furthermore, the KBr method was used for IR measurement. More specifically, a small amount of sample and dry KBr were ground and mixed in an agate mortar, and then compression molded to form a thin film. Using the thin film sample, the absorption in the infrared region of 600 to 4000 cm ⁻¹ was measured at room temperature.

<About ¹ H-NMR>
¹ H-NMR (400 MHz, CDCl ₃ ): δ 1.77-1.89 (m, 8H), 4.20 (t, 4H, J = 6.0 Hz), 4.26-4.32 (m, 4H), 5.81 (dd, 2H, J = 1.5, 10.3 Hz), 6.10 (dd, 2H, J = 10.3, 17.3 Hz), 6.39 (dd, 2H, J = 1.5, 17.3 Hz), 7.20-7.45 (m, 11H), 7.48-7.51 (m, 2H), 8.17 (dd, 1H, J = 1.5, 8.3 Hz), 8.23 (d, 1 H, J = 8.3 Hz), 8.49 (d, 1 H, J = 1.5 Hz)

<About ¹³ C-NMR>
¹³ C-NMR (100 MHz, CDCl ₃ ): δ 25.1, 25.4, 63.9, 68.4, 87.0, 96.6, 122.17, 122.19, 122.5, 122. 6, 125.1, 128.4, 128.5, 129.1, 130.9, 131.3, 131.9, 132.8, 135.0, 135.7, 148.1, 148.2, 148.8, 148.9, 153.5, 163.5, 163.8, 166.2

<About IR>
IR (KBr, cm ⁻¹ ): 2961, 2142, 1765, 1726, 1507, 1184

Example 1
A PVA alignment film was formed on the highly bent glass plate by spin coating a 5 wt.% Polyvinyl alcohol aqueous solution at 2000 rpm for 10 seconds on the highly bent glass plate and heating at 150 ° C. for 1 hour. By rubbing the surface of such an alignment film, 100 parts by weight of the compound of the chemical structural formula 2 obtained in Production Example 1 above, 3 parts by weight of a photopolymerization initiator Irgacure 907 (manufactured by Ciba Specialty Chemicals) and A thin film was formed by applying a liquid crystal composition solution prepared by dissolving 0.05 parts by weight of an acrylic acid copolymer-based leveling agent (“BYK361” manufactured by Big Chemie) in 200 parts by weight of cyclopentanone by spin coating. This thin film was dried for 1 minute in an air circulating thermostat kept at 90 ° C. ± 1 ° C., and then allowed to cool to room temperature to form a horizontally oriented nematic monodomain phase. Furthermore, using an ultraviolet irradiation device using a metal halide lamp as a light source, 600 mJ / cm ² of ultraviolet light was irradiated from the side coated with the liquid crystal composition solution in an air atmosphere to perform photopolymerization, and the alignment state was fixed. Abbe refracted the refractive index of the optical thin film thus prepared (the liquid crystal composition after being aligned and fixed. In this embodiment, the portion excluding the highly bent glass plate and the PVA alignment film corresponds to this). It was measured by a total _{of, n e = 1.631, n o} = 1.585, was Δn = 0.046. Further, when the wavelength dispersion characteristic was measured using a spectroscopic ellipsometer, D ₁ (Re) = Re (450) / Re (550) = 1.035, D ₂ (Re) = Re (650) / Re (550) = 0.979.

前記化学構造式３で示されるモノマー（１．０ｇ，１．３６ｍｍｏｌ）、フェニルアセチレン（１．１７ｇ，１．６３ｍｍｏｌ）、ＰｄＣｌ_２（ＰＰｈ_３）_２（４７．６ｍｇ，６７．８μｍｏｌ）、トリフェニルホスフィン（７１．１ｍｇ，０．２７ｍｍｏｌ）、ヨウ化銅（Ｉ）（５１．６ｍｇ、０．２７ｍｍｏｌ）、重合禁止剤としてＢＨＴを微量に含むＴＨＦ溶液（５ｍｌ）にトリエチルアミン（０．５ｍｌ）を加え、８０℃で１２時間攪拌した。反応終了後に１Ｎ塩酸を加え、ジクロロメタンで抽出した。有機層は、飽和食塩水で洗浄した後、硫酸マグネシウムで乾燥させた。和光純薬製「フロリジール７５〜１５０μｍ（１００〜２００ｍｅｓｈ）」のショートカラムを通した後、エバポレーションで溶媒を除き、イソプロピルアルコールから再結晶させることにより、前記化学構造式４で示される化合物が０．８６ｇ（８３％）得られた。 (Production Example 2)

Monomer (1.0 g, 1.36 mmol) represented by the chemical structural formula 3, phenylacetylene (1.17 g, 1.63 mmol), PdCl ₂ (PPh ₃ ) ₂ (47.6 mg, 67.8 μmol), triphenyl Add triethylamine (0.5 ml) to a THF solution (5 ml) containing phosphine (71.1 mg, 0.27 mmol), copper (I) iodide (51.6 mg, 0.27 mmol), and BHT in a trace amount as a polymerization inhibitor. , And stirred at 80 ° C. for 12 hours. 1N hydrochloric acid was added after completion | finish of reaction, and the dichloromethane extracted. The organic layer was washed with saturated brine and dried over magnesium sulfate. After passing through a short column of “Florisil 75-150 μm (100-200 mesh)” manufactured by Wako Pure Chemical Industries, the solvent is removed by evaporation and recrystallized from isopropyl alcohol, whereby the compound represented by the chemical structural formula 4 is 0. Obtained .86 g (83%).

The liquid crystal temperature range was as follows.
Liquid crystal temperature range (at elevated temperature): Melting point 79 ° C
Liquid crystal temperature range (when the temperature falls): 38-22 ° C

The spectral data of the compound represented by the chemical structural formula 4 are shown below. In addition, the measuring method of < ¹ > H-NMR, < ¹³ > C-NMR, and IR is the same as that mentioned above.

<About ¹ H-NMR>
¹ H-NMR (400 MHz, CDCl ₃ ): δ 1.41-1.56 (m, 8H), 1.71 (quint, 4H, J = 6.4 Hz), 1.81 (quint, 4H, J = 6.6 Hz), 3.96 (t, 2H, J = 6, 4 Hz), 3.97 (t, 2H, J = 6.4 Hz), 4.17 (t, 4H, J = 6.6 Hz), 5.81 (dd, 2H, J = 1.5, 10.3 Hz), 6.12 (dd, 2H, J = 10.3, 17.3 Hz), 6.39 (dd, 2H, J = 1. 5, 17.3 Hz), 6.91-6.96 (m, 4H), 7.11-7.21 (m, 4H), 7.29-7.36 (m, 3H), 7.51- 7.53 (m, 2H)

<About ¹³ C-NMR>
¹³ C-NMR (100 MHz, CDCl ₃ ): δ 25.8, 28.6, 29.2, 64.5, 68.3, 87.2, 96.2, 115.2, 122.3, 122. 4, 122.8, 124.8, 128.4, 128.6, 129.0, 129.1, 130.5, 131.2, 132.0, 133.0, 135.2, 135.6, 144.1, 144.2, 157.06, 157.12, 164.1, 164.5, 166.4

<About IR>
IR (KBr, cm ⁻¹ ): 2942, 2211, 1727, 1511, 1192

(Example 2)
75 parts by weight of the compound of the chemical structural formula 4 obtained in Production Example 2, 25 parts by weight of a liquid crystal mixture of a polymerizable rod-like nematic liquid crystal compound LC242 (manufactured by BASF), Irgacure 819 (Ciba Specialty) A liquid crystal composition solution was prepared by dissolving 3 parts by weight of Chemicals) and 0.05 part by weight of an acrylic acid copolymer leveling agent (“BYK361” manufactured by Big Chemie) in 200 parts by weight of cyclopentanone. This liquid crystal composition solution was applied by spin coating on a highly bent glass plate prepared in the same manner as in Example 1 and subjected to rubbing treatment to form a thin film. This thin film was dried for 1 minute in an air circulating thermostat kept at 90 ° C. ± 1 ° C., and then allowed to cool to room temperature to form a horizontally oriented nematic monodomain phase. Furthermore, using an ultraviolet irradiation device using a metal halide lamp as a light source, 600 mJ / cm ² of ultraviolet light was irradiated from the side coated with the liquid crystal composition solution in an air atmosphere to perform photopolymerization, and the alignment state was fixed. Thus, Δn of the optical thin film produced by changing the mixing ratio of the compound of the chemical structural formula 4 and LC242 was measured with an Abbe refractometer, and Δn = 0.060. Further, when the wavelength dispersion characteristic was measured using a spectroscopic ellipsometer, D ₁ (Re) = Re (450) / Re (550) = 1.047, D ₂ (Re) = Re (650) / Re (550) = 0.973.

(Example 3)
In the same manner as in Example 2, when Δn of an optical thin film obtained using 50 parts by weight of the compound of the chemical structural formula 4 and the liquid crystal composition of LC242 (50 parts by weight) was measured, Δn = 0.080. there were. Further, when the wavelength dispersion characteristic was measured using a spectroscopic ellipsometer, D ₁ (Re) = Re (450) / Re (550) = 1.063, D ₂ (Re) = Re (650) / Re (550) = 0.969.

(Comparative Example 1)
LC242 was measured [Delta] n of the optical thin film obtained by using the liquid crystal composition (100 parts by _{weight) Δn = 0.131 (n e =} 1.654, n o = 1.523) was. Further, when the wavelength dispersion characteristic was measured using a spectroscopic ellipsometer, D ₁ (Re) = Re (450) / Re (550) = 1.082, D ₂ (Re) = Re (650) / Re (550) = 0.960.

(Example 4)
The liquid crystal composition solution used in Example 1 was applied on a stretched PET film fixed on a glass plate by a bar coating method to form a thin film. This thin film was dried for 1 minute in an air circulating thermostat kept at 90 ° C. ± 1 ° C., and then allowed to cool to room temperature to form a horizontally oriented nematic monodomain phase. Furthermore, using an ultraviolet irradiation device using a metal halide lamp as a light source, 600 mJ / cm ² of ultraviolet light was irradiated from the side coated with the liquid crystal composition solution in an air atmosphere to perform photopolymerization, and the alignment state was fixed. This optical thin film (which is a liquid crystal composition after being aligned and fixed, corresponds to the portion excluding the glass plate and the stretched PET film in this example, and the average thickness thereof was 2.31 μm). The sample was transferred to a plate to prepare a sample of 10 cm × 10 cm. As shown in FIG. 1, when the phase difference value Re (590) at nine locations in the plane (see reference numeral 1 in the figure) was measured with a spectroscopic ellipsometer, the average phase difference value was 138.5 nm. The variation in the phase difference value was ± 2.4 nm. Moreover, the light transmittance in wavelength 590nm measured with the ultraviolet visible spectrophotometer was 92%.

(Comparative Example 2)
Using the same method as in Example 4, an LC242 optical thin film was produced. The obtained optical thin film (average thickness: 1.07 μm) was transferred to a glass plate to prepare a 10 cm × 10 cm sample, and a spectroscopic ellipsometer was used to obtain nine phase differences at equal intervals in the plane as shown in FIG. When the value Re (590) was measured, the average phase difference value was 141.2 nm and the phase difference value variation was ± 6.8 nm.

  Thus, in the liquid crystal monomers of Examples 1 to 3, Δn was 0.046 to 0.080, which was smaller than the conventional LC242 (Δn = 0.131). Moreover, in the retardation film of Example 4 produced using the liquid crystal monomer of Example 1, the light transmittance is 92% and the transparency is excellent, and the thickness of the retardation film (thickness of the optical thin film) is 2 Even if it is as small as .31 μm, since the liquid crystal monomer having Δn of 0.046, which is smaller than the conventional one, is used, the unevenness of the retardation value (= Δn × thickness) of the retardation film is also reduced. Therefore, an extremely high coating accuracy is not required, and a retardation film that can be easily applied with a desired small thickness and has excellent productivity can be obtained.

FIG. 1 is a plan view showing measurement points of a phase difference plate using a spectroscopic ellipsometer.

Explanation of symbols

  1. Phase difference measurement point

Claims (14)

A liquid crystalline di (meth) acrylate compound represented by the following formula (I):

Here, in Formula (I), R ¹ and R ² each independently represent a hydrogen atom or a methyl group, R ³ and R ⁴ each independently represent an alkylene group having 2 to 12 carbon atoms, R ⁵ and R ⁶ each independently represent —O—CO— or —CO—O—, A ¹ and A ² each independently represents —O— or —O—CO—O—, and X represents An unsubstituted phenyl group or naphthyl group, or an unsubstituted thiophenyl group, furanyl group or pyrrolyl group is shown. 2. The liquid crystalline di (meth) acrylate compound according to claim 1, wherein X is an unsubstituted phenyl group . Wherein R ³ and R ⁴ are each independently an alkylene group having 2 to 6 carbon atoms, wherein X is liquid crystalline di (meth) acrylate compound according to claim 1, wherein the phenyl group der Turkey .   A retardation film obtained by aligning and fixing a composition containing the liquid crystalline di (meth) acrylate compound according to claim 1 on a substrate.   The retardation film according to claim 4, wherein the liquid crystalline di (meth) acrylate compound has a birefringence of 0.01 to 0.10 at a wavelength of 589 nm. The composition is cured by irradiating with ultraviolet light,
Irradiation amount of the ultraviolet rays, a retardation film according to claim 4 or 5, characterized in that a 100~1500mJ / cm ^2.   The retardation film according to claim 4, wherein the composition has a thickness of 1 to 10 μm after being oriented and fixed on the base material.   The retardation film according to any one of claims 4 to 7, wherein the light transmittance at a wavelength of 590 nm is 80% or more. The retardation film in any one of Claim 4 to 8 with which retardation value Re (590) in retardation film surface in wavelength 590nm satisfies following formula (1).
80 nm ≦ Re (590) ≦ 800 nm (1)
Here, Re (590) = (nx−ny) × d, where nx is the refractive index in the slow axis direction of the retardation film (the direction in which the refractive index in the retardation film is maximized), and ny is The refractive index in the fast axis direction of the retardation film, and d [nm] means the thickness of the retardation film.   An optical film comprising the retardation film according to claim 4 laminated thereon.   A polarizing plate comprising the retardation film according to claim 4 or the optical film according to claim 10 disposed on at least one side of a polarizer. A retardation film according to any one of claims 4 to 9, an optical film according to claim 10, or a polarizing plate according to claim 11,
A liquid crystal panel comprising a liquid crystal cell.   The liquid crystal panel according to claim 12, wherein the liquid crystal cell is a TN mode, a VA mode, an IPS mode, or an OCB mode.   A liquid crystal display device comprising the liquid crystal panel according to claim 12.

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