JP2005139375A - Block-type liquid crystal polymer, liquid crystal polymer composition, and liquid crystal film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a block-type liquid crystal polymer which can be improved in the surface hardness of a liquid crystal film as the liquid crystal polymer keeps the optical characteristics (the property of alignment), and to provide a liquid crystal polymer composition containing the above block-type liquid crystal polymer, and also to provide a liquid crystal film and an inclined alignment film which are obtained by film-forming the above block-type liquid crystal polymer or the above liquid crystal polymer composition, and moreover to provide an optical film and a picture-displaying device by using them. <P>SOLUTION: The block-type liquid crystal polymer comprises each unit of (a) a liquid crystal monomer, (b) a non-liquid crystal monomer having a long-chain alkyl group and (c) a crosslinkable monomer and has at least a unit of block structure formed with the units of (c) the above crosslinkable monomer. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a block type liquid crystal polymer and a liquid crystal polymer composition containing the block type liquid crystal polymer. The block type liquid crystal polymer of the present invention can be used as a material for forming a liquid crystal film or a tilted alignment film. The liquid crystal film and the tilted alignment film can be used for various optical film applications, for example, alone or in combination with other optical films, and can be used as an optical film such as a retardation plate, a viewing angle compensation film, and an optical compensation film. Furthermore, the present invention relates to an image display device such as a liquid crystal display device, an organic EL display device, and a PDP using the liquid crystal film, the tilt alignment film, and the optical film.

The demand for a wide viewing angle is increasing as the liquid crystal display becomes larger, and various methods for widening the viewing angle have been proposed. One of them is a method using an optical compensation film, which has already been put into practical use. As a method of obtaining an optical compensation film, there is a method of tilting and aligning liquid crystals. Examples of the tilt alignment method include oblique vapor deposition and photo-alignment. A method using alignment of liquid crystal has also been proposed (Patent Documents 1 to 3). However, a film in which liquid crystal is aligned has a problem that the surface hardness is insufficient. Specifically, Patent Document 3 proposes a method for producing a tilted alignment film by aligning a liquid crystal material on an alignment film, but the tilted alignment film obtained from this liquid crystal material has low hardness. There is a problem that the surface is easily scratched.
Japanese Patent Laid-Open No. 7-20434 JP-A-8-5838 JP 2002-214431 A

  An object of this invention is to provide the block-type liquid crystal polymer which can improve the surface hardness of a liquid crystal film, maintaining the optical characteristic (orientation) of a liquid crystal polymer. Another object of the present invention is to provide a liquid crystal polymer composition containing the block type liquid crystal polymer. Another object of the present invention is to provide a liquid crystal film and a tilted alignment film obtained by forming the block type liquid crystal polymer or liquid crystal polymer composition. Furthermore, it aims at providing the optical film and image display apparatus using them.

  As a result of intensive studies to solve the above problems, the present inventors have found that the above object can be achieved by the following block type liquid crystal polymer and liquid crystal polymer composition, and have completed the present invention. That is, the present invention is as follows.

  1. It has at least a liquid crystal monomer (a) unit, a non-liquid crystal monomer (b) unit having a long-chain alkyl group, and a crosslinkable monomer (c) unit, and at least a block structural unit composed of the crosslinkable monomer (c) unit. A block-type liquid crystal polymer.

  2. 2. The block-type liquid crystal polymer according to 1 above, wherein the proportion of the block structural unit composed of the crosslinkable monomer (c) unit in the polymer is 10 to 40% by weight.

  3. 3. The block type liquid crystal polymer according to 1 or 2 above, wherein the liquid crystal monomer (a) contains a nematic liquid crystal monomer (a1).

  4). The nematic liquid crystal monomer (a1) has the general formula (a1):

（式中、Ｒ¹ は水素原子またはメチル基を、ｍは１〜６の整数を、Ｘ¹ は−ＣＯ₂ −基、−ＯＣＯ−基、−ＣＯ−、−ＣＨ＝ＣＨ−または−Ｃ≡Ｃ−を、Ｒ² は炭素数１〜６のアルコキシ基、シアノ基、フルオロ基または炭素数１〜６のアルキル基を、ｐおよびｑは１または２を示す。）で表されるアクリル酸エステル誘導体である上記３記載のブロック型液晶ポリマー。

(Wherein R ¹ represents a hydrogen atom or a methyl group, m represents an integer of 1 to 6, X ¹ represents a —CO ₂ — group, —OCO— group, —CO—, —CH═CH— or —C≡) C-, R ² represents an alkoxy group having 1 to 6 carbon atoms, a cyano group, a fluoro group, or an alkyl group having 1 to 6 carbon atoms, and p and q represent 1 or 2.) 4. The block type liquid crystal polymer as described in 3 above, which is a derivative.

  5). 5. The block type liquid crystal polymer according to any one of the above 1 to 4, having a number average molecular weight of 2,000 to 100,000.

  6). 6. The block type liquid crystal polymer according to any one of 1 to 5 above, which is obtained by living radical polymerization of each monomer.

  7). 7. The block type liquid crystal polymer according to any one of 1 to 6, wherein the crosslinkable monomer (c) is a monomer having an epoxy group.

  8). 7. The block type liquid crystal polymer according to any one of 1 to 6 above, wherein the crosslinkable monomer (c) is a monomer having a hydroxyl group.

  9. 7. The block type liquid crystal polymer according to any one of 1 to 6, wherein the crosslinkable monomer (c) is an alkyl (meth) acrylate having an alkyl group having 1 to 11 carbon atoms.

  10. 9. A liquid crystal polymer composition comprising the block type liquid crystal polymer according to the above 7 or 8, and an ultraviolet cation initiator.

  11. 10. A liquid crystal polymer composition comprising the block type liquid crystal polymer according to 9 above and a radical generator.

  12 A liquid crystal film obtained by forming the block-type liquid crystal polymer according to any one of 1 to 9 or the liquid crystal polymer composition according to 10 or 11 above.

  13. 13. The liquid crystal film as described in 12 above, wherein the block type liquid crystal polymer forms a crosslinked structure.

  14 The block-type liquid crystal polymer according to any one of 1 to 9 above, or the liquid crystal polymer composition according to 10 or 11 above, which is obtained by aligning on a substrate having an alignment regulating force in the horizontal direction and forming a film. Alignment film.

  15. 15. The inclined alignment film according to 14 above, wherein the block type liquid crystal polymer forms a crosslinked structure.

  16. 14. An optical film in which at least one optical film is laminated on the liquid crystal film according to 12 or 13, or the inclined alignment film according to 14 or 15.

  17. 16. An image display device using the liquid crystal film according to 12 or 13, the inclined alignment film according to 14 or 15, or the optical film according to 16.

  The block type liquid crystal polymer of the present invention is a liquid crystal polymer obtained by copolymerizing at least a liquid crystal monomer (a), a non-liquid crystal monomer (b) having a long chain alkyl group, and a crosslinkable monomer (c), and at least The crosslinkable monomer (c) unit forms a block structural unit. The liquid crystal monomer (a) and the non-liquid crystal monomer (b) having a long-chain alkyl group form a unit having a liquid crystal function, and the crosslinkable monomer (c) forms a unit having a crosslinking function. The crosslinkable monomer (c) unit introduced into the block type liquid crystal polymer forms a block structural unit and can effectively crosslink the block type liquid crystal polymer by reaction between functional groups or radical reaction. Therefore, the surface hardness of the liquid crystal film or the like can be improved while maintaining the optical characteristics (orientation).

  Moreover, since the block type liquid crystal polymer of the present invention contains a non-liquid crystal monomer (b) unit having a long-chain alkyl group as a vertical alignment component, a vertical alignment film can be formed by film formation. Further, when the block-type liquid crystal polymer is formed on a substrate having an alignment regulating force in the horizontal direction, an inclined alignment film can be formed by inclining alignment from the regulating force in the vertical direction and the horizontal direction.

  The block type liquid crystal polymer of the present invention is a liquid crystal polymer obtained by copolymerizing at least a liquid crystal monomer (a), a non-liquid crystal monomer (b) having a long chain alkyl group, and a crosslinkable monomer (c), and at least the above-mentioned It has a block structural unit consisting of a crosslinkable monomer (c) unit. It is preferable that 80 mol% or more of the crosslinkable monomer (c) units form a block structural unit, and more preferably 90 mol% or more. Most preferably, all of the crosslinkable monomer (c) units form a block structural unit. By polymerizing the crosslinkable monomer (c) to form a block structure, the crosslinkability when irradiated with radiation is improved, and as a result, the surface hardness of the liquid crystal film and the like is increased. When two or more kinds of crosslinkable monomers (c) are used in combination, a block structure composed of each crosslinkable monomer (c) unit may be formed in the block structural unit, and random copolymerization may be performed. May be.

  The liquid crystal monomer (a) and the non-liquid crystal monomer (b) may be copolymerized randomly, and the liquid crystal monomer (a) unit and the non-liquid crystal monomer (b) unit may each form a block structural unit. That is, the block-type liquid crystal polymer of the present invention has a block structural unit (crosslinkable unit) composed of at least a crosslinkable monomer (c) unit, and a multi-block structure having more block structural units is also possible. . When not only the crosslinkable monomer (c) unit but also the liquid crystal monomer (a) unit and the non-liquid crystal monomer (b) unit are each formed into a block structure unit, the liquid crystal polymer is formed into a film and aligned to obtain a phase. A liquid crystal film or the like having a separation structure is obtained. Such a block-type liquid crystal polymer can be used as a material that expresses liquid crystals in units.

  Examples of the crosslinkable monomer (c) include a monomer having a crosslinkable functional group and an alkyl (meth) acrylate having an alkyl group having 1 to 11 carbon atoms. Examples of the crosslinkable functional group include a hydroxyl group, an epoxy group, a carboxyl group, an acid anhydride group, an amino group, an isocyanate group, and an aziridine group. Among these, a monomer having a hydroxyl group or an epoxy group is preferable. Such a crosslinkable monomer (c) may be used alone or in combination of two or more.

Examples of the monomer having a hydroxyl group include a formula: CH ₂ = CR ¹ COOR ² (wherein R ¹ is a hydrogen atom or a methyl group, and R ² is an alkyl group having 2 to 6 carbon atoms having at least one hydroxyl group). ) Represented by hydroxyalkyl (meth) acrylate. For example, 2-hydroxyethyl (meth) acrylate, 3-hydroxypropyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 8-hydroxyoctyl (meth) acrylate, 10-hydroxy Examples include decyl (meth) acrylate, 12-hydroxylauryl (meth) acrylate, and (4-hydroxymethylcyclohexyl) methyl acrylate. Examples of the monomer having a hydroxyl group other than the above include N-methylol (meth) acrylamide, vinyl alcohol, allyl alcohol, 2-hydroxyethyl vinyl ether, 4-hydroxybutyl vinyl ether, and diethylene glycol monovinyl ether.

  Examples of the monomer having an epoxy group include glycidyl (meth) acrylate and 3,4-epoxycyclohexylmethyl (meth) acrylate.

  Moreover, (meth) acrylic acid etc. are mention | raise | lifted as a monomer which has a carboxyl group. However, in the living radical polymerization method, a monomer having a carboxyl group cannot be directly polymerized as a block unit. This is presumably because the carboxyl group deactivates the transition metal that is the activator. In the living radical polymerization method, a monomer having a carboxyl group precursor in the molecule is used to form a block polymer, and then converted to a carboxyl group, thereby converting the monomer unit having a carboxyl group into a block type liquid crystal. It can be introduced into the polymer.

  The monomer having a carboxyl group precursor in the molecule does not deactivate the transition metal as an activator during living radical polymerization, and is decomposed by an acid catalyst after polymerization to generate a free carboxyl group. Any precursor group may be used. Examples of such a monomer include t-butyl (meth) aclute and trimethylsilyl (meth) acrylate.

The method for converting the precursor group into a carboxyl group is not particularly limited, but usually, a method of heat-treating the block type liquid crystal polymer in the presence of an acid catalyst is preferably used. Examples of the acid catalyst include H ⁺ type ion exchange resins such as sulfonic acid type, organic acids such as p-toluenesulfonic acid and benzenesulfonic acid, and inorganic acids such as hydrochloric acid and sulfuric acid. Further, there is a method in which a photoacid generator is added to a block type liquid crystal polymer, and an ultraviolet ray is irradiated to generate an acid catalyst made of Bronsted acid, followed by heat treatment. In addition, as a photo-acid generator, the ultraviolet cation initiator etc. which are used as a reaction adjuvant mentioned later are mention | raise | lifted.

  Examples of the alkyl (meth) acrylate having an alkyl group having 1 to 11 carbon atoms include methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, and isooctyl (meth). Examples include acrylate, isononyl (meth) acrylate, and decyl (meth) acrylate. These may be used alone or in combination of two or more. Such an alkyl (meth) acrylate is capable of cross-linking the polymer by this radical active species by generating a radical in the polymer by extracting hydrogen from the side chain alkyl group by a radical generated from a radical generator described later. . When the side chain alkyl group has 12 or more carbon atoms, the crosslinkability is poor, which is not preferable. The carbon number of the side chain alkyl group is preferably 9 or less, more preferably 8 or less. On the other hand, the side chain alkyl group preferably has 4 or more carbon atoms.

  The proportion of the block structural unit of the crosslinkable monomer (c) in the polymer is preferably 10 to 40% by weight, more preferably 10 to 30% by weight. When the proportion of the block structural unit of the monomer (c) is less than 10% by weight, crosslinking does not occur sufficiently, and it tends to be difficult to increase the surface hardness of the liquid crystal film. On the other hand, when the proportion of the block structural unit of the monomer (c) exceeds 40% by weight, the optical properties as the liquid crystal polymer tend to be adversely affected. The block structural unit is most preferably composed of only a crosslinkable monomer (c) unit. However, the block structural unit is a monomer unit having no crosslinkability within a range that does not substantially hinder the crosslinkability. You may have. Thereby, mechanical characteristics and the like can be changed.

  Examples of the monomer having no crosslinkability include styrene monomers such as styrene and α-methylstyrene, alicyclic (meth) acrylates such as isobornyl (meth) acrylate and cyclohexyl (meth) acrylate, and (meth) acryloylmorpholine. , (Meth) acrylamide, nitrogen-containing (meth) acrylates such as acrylonitrile, vinyl acetate and the like. The content of the monomer unit having no crosslinkability in the block structural unit is preferably 20% by weight or less, and more preferably 10% by weight or less.

  The non-liquid crystal monomer (b) acts as a vertical alignment component. The carbon number of the long chain alkyl group of the non-liquid crystal monomer (b) is 12 or more, preferably 12 to 28. When the number of carbon atoms is less than 12, it is not preferable because the vertical alignment is poor. Further, by applying a vertically aligned liquid crystal polymer having a non-liquid crystal monomer (b) unit on a substrate having an alignment regulating force in the horizontal direction, an inclined alignment film (liquid crystal film) that is inclined and aligned can be obtained.

  Examples of the non-liquid crystal monomer (b) having a long-chain alkyl group include alkyl (meth) acrylates having an alkyl group having 12 to 28 carbon atoms in the side chain. Examples of the non-liquid crystal monomer (b) include octadecyl (meth) acrylate, lauryl (meth) acrylate, mistyryl (meth) acrylate, palmityl (meth) acrylate, stearyl (meth) acrylate, and the like. The non-liquid crystal monomer (b) may be used alone or in combination of two or more. The ratio of the non-liquid crystal monomer (b) unit in the liquid crystal polymer is not particularly limited, but is preferably 10 to 40% by weight, and more preferably 15 to 30% by weight. When the proportion of the non-liquid crystal monomer (b) unit is less than 10% by weight, the orientation tends to be inferior, whereas when it exceeds 40% by weight, the optical properties as the liquid crystal polymer tend to be adversely affected. In addition, the vertical orientation tends to be too high and it becomes difficult to obtain the tilt orientation.

  Various liquid crystal monomers (a) can be used, and can be appropriately selected and used depending on the application. Examples thereof include nematic liquid crystal monomers, smectic liquid crystal monomers, cholesteric liquid crystal monomers, and the like. The ratio of the liquid crystal monomer (a) unit in the liquid crystal polymer is not particularly limited, but is preferably 40 to 80% by weight, and more preferably 50 to 70% by weight. When the ratio of the liquid crystal monomer (a) unit is less than 40% by weight, the liquid crystallinity is poor, the orientation is lowered, and the tilted alignment is hardly formed. On the other hand, when it exceeds 80% by weight, it becomes easy to align in the horizontal direction according to the alignment film, and it becomes difficult to form an inclined alignment.

  As the liquid crystal monomer (a), a nematic liquid crystal monomer (a1) is preferably used. Examples of the nematic liquid crystal monomer (a1) include those having an acryloyl group or a methacryloyl group as a polymerizable functional group, and a mesogenic group composed of a cyclic unit or the like. Examples of the cyclic unit serving as a mesogenic group include biphenyl, phenylbenzoate, phenylcyclohexane, azoxybenzene, azomethine, azobenzene, phenylpyrimidine, diphenylacetylene, diphenylbenzoate, and bicyclohexane. Cyclohexylbenzene, terphenyl 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. The mesogenic group may be bonded via a spacer portion that imparts flexibility. Examples of the spacer portion include a polymethylene chain and a polyoxymethylene chain. The number of repeating structural units forming the spacer portion is appropriately determined depending on the chemical structure of the mesogenic portion, but the repeating unit of the polymethylene chain is 0 to 20, preferably 2 to 12, and the repeating unit of the polyoxymethylene chain is 0 to 0. 10, preferably 1-3.

  As the nematic liquid crystal monomer (a1), for example, the general formula (a1):

（式中、Ｒ¹ は水素原子またはメチル基を、ｍは１〜６の整数を、Ｘ¹ は−ＣＯ₂ −基、−ＯＣＯ−基、−ＣＯ−、−ＣＨ＝ＣＨ−または−Ｃ≡Ｃ−を、Ｒ² は炭素数１〜６のアルコキシ基、シアノ基、フルオロ基または炭素数１〜６のアルキル基を、ｐおよびｑは１または２を示す。）で表されるアクリル酸エステル誘導体があげられる。

(Wherein R ¹ represents a hydrogen atom or a methyl group, m represents an integer of 1 to 6, X ¹ represents a —CO ₂ — group, —OCO— group, —CO—, —CH═CH— or —C≡) C-, R ² represents an alkoxy group having 1 to 6 carbon atoms, a cyano group, a fluoro group, or an alkyl group having 1 to 6 carbon atoms, and p and q represent 1 or 2.) Derivatives.

In the acrylate derivative represented by the general formula (a1), p = 1 is preferable, q = 2 is preferable, R ¹ is preferably a hydrogen atom, R ² is preferably a cyano group, and X ¹ is − COO-groups are preferred. Specific examples of the acrylate derivative represented by the general formula (a) include 4- (4-cyanobiphenyloxycarbonyl) phenoxyethyl acrylate, 4- (4-cyanobiphenyloxycarbonyl) phenoxypropyl acrylate, 4 Examples include-(4-cyanobiphenyloxycarbonyl) phenoxybutyl acrylate, 4- (4-cyanobiphenyloxycarbonyl) phenoxypentyl acrylate, 4- (4-cyanobiphenyloxycarbonyl) phenoxyhexyl acrylate, and the like. These may be used alone or in combination.

  The block type liquid crystal polymer of the present invention can be prepared by a living radical polymerization method. The living radical polymerization method uses a transition metal and its ligand as an activator as shown in JP-T-10-509475 (Patent No. 3040172), and in the presence of these, In this method, a polymerization reaction is advanced using a polymerization initiator.

  Radical polymerization is the most widely used polymerization method in the industry, and it is widely used for the variety of polymerizable monomers, the ease of handling of the reaction system, and the reduction in production cost based on it. In order to obtain a polymer with a controlled molecular weight by radical polymerization, it is difficult to select the amount of initiator and control the polymerization heat. A polymerization method that solves the problem includes a so-called living radical polymerization method or ATRP method.

  References for the living radical polymerization method include, for example, a report by Patten et al., “Radical Polymerization Yielding Polymers with Mw / Mn to 1.05 by Homogenous Atom Transfer Radical Polymer 57”, 19). Alternatively, a report by Matyjawski et al., “Controlled / Living Radical Polymerization. Halogen Atom Transfer Radical Polymerization Promoted by a Cu (I) / Cu (II) Redox Process ", Macromolecules l995, 28, 7901-10 (October 15, 1995); WO 96/30421 (October 3, 1996); Sawamoto et al., "" Ruthium-mediated Living Radical Polymerization of Methyl Methacrylate Macromolecules, 1996, 29, 1070. Etc. are known.

  For example, a non-liquid crystal monomer (b) is added to a polymer obtained by living polymerizing a liquid crystal monomer (a) (block body a), and the non-liquid crystal monomer (b) is sequentially added to the polymer terminal of the block a. By doing so, the block body b which is the secondary block is introduced, and the diblock polymer AB in the ab form can be obtained. Thereafter, a crosslinkable monomer (c) is added to the diblock polymer AB, and the monomer (c) is sequentially added to the polymerization terminal of the diblock polymer AB. It can be introduced to obtain the abc type triblock polymer ABC. Similarly, a triblock polymer ACB in the acb form can also be obtained. The order of the block structure portions is not particularly limited, and block polymers having various structures can be formed.

  In addition, when plural types are used as the liquid crystal monomer (a), the non-liquid crystal monomer (b), and the monomer (c) as each constituent monomer, higher order blocks such as a tetrablock polymer, a pentablock polymer, a hexablock polymer, etc. It can also be a polymer.

  It is preferable that the monomer added to the living polymerized polymer from the middle is when the polymerization rate of the polymer being polymerized exceeds at least 80% by weight, more preferably when it exceeds 90% by weight. The polymerization rate is defined by (residual monomer / prepared monomer amount before polymerization) x 100 (%), measured by volatilization and removal of monomer components by heating, gel permeation chromatography, gas chromatography, or liquid chromatography can do.

  If the polymerization rate of the polymer block being polymerized is too high, the polymerization terminal is deactivated, the molecular weight distribution becomes wide, or the polymerization does not proceed. On the other hand, when the polymerization rate of the polymer block being polymerized is low, the addition of monomers of other blocks tends to increase the number of structural units for random copolymerization.

  During the living radical polymerization, it is necessary to remove dissolved oxygen in the monomer. Methods for lowering the dissolved oxygen concentration include stirring while blowing an inert gas such as nitrogen or argon, a method of bubbling an inert gas into the monomer, a method of degassing under reduced pressure, a method of degassing by heating, etc. There is. These methods may be used in combination.

  As the polymerization initiator, an ester having bromine or chlorine at the α-position or a styrene derivative is suitable. Preferred examples include 2-bromo (or chloro) propionic acid derivatives or chloro (or bromide) 1-phenyl derivatives. Among them, particularly preferred are methyl 2-bromo (or chloro) propionate, ethyl 2-bromo (or chloro) propionate, methyl 2-bromo (or chloro) -2-propionate, 2-bromo (or chloro) -2. -A halogen compound selected from ethyl propionate, 1-phenylethyl chloride (or bromide), and ethyl 2-bromoisobutyrate can be used. As the initiator having a hydroxyl group, for example, 2-hydroxy-2-methylpropionic acid-2-hydroxyethyl can be used. By using an initiator having a hydroxyl group, the hydroxyl group can be introduced into the liquid crystal polymer. Bifunctional initiators can also be used. Specific examples include ethylene bis (2-bromo-2-methylpropionate).

  In the polymerization, the number average molecular weight of the obtained block copolymer can be intentionally controlled. In such a polymerization method, a transition metal and a ligand are used as a catalyst other than the initiator.

  As the transition metal, Cu, Ru, Fe, Rh, V, Ni metal species, and metal salts or metal complexes thereof can be used. The ligand is not particularly limited, and for example, bipyridyl derivatives, amine derivatives, mercaptan derivatives, trifluorate derivatives, and the like can be used. Among these, it is particularly preferable to use Cu (I) and a 2,2′-bipyridyl complex in view of the stability and speed of polymerization.

  The polymerization initiator is usually 0.05 to 30 mol%, preferably 0.1 to 10 mol%, more preferably 0. It is used at a ratio of 1 to 5 mol%. Moreover, the usage-amount of a transition metal is 0.01-3 mol part normally with respect to 1 mol part of said polymerization initiators as forms, such as a halide, Preferably it is used in the ratio of 0.1-1 mol part. . Further, the ligand is used in a proportion of usually 0.5 to 5 mol parts, preferably 1 to 3 mol parts, relative to 1 mol part of the transition metal (form of halide, etc.). When the polymerization initiator and the activator are used in such proportions, good results can be obtained in the reactivity of living radical polymerization, the molecular weight of the produced polymer, and the like.

  In the polymerization method, the monomer component which is liquid at the polymerization temperature can be produced using a solvent or without a solvent. Since the liquid crystal monomer is not usually liquid, it is dissolved in a solvent and polymerized. Any solvent may be used as long as it dissolves the liquid crystal monomer. Solvents include tetrahydrofuran, anisole, dimethylacetamide, cyclohexanone. Cyclopentanone or the like can be used. Usually, the polymerization is carried out at a monomer concentration of about 10 to 30% by weight.

  Further, after the liquid crystal monomer (a) and the non-liquid crystal monomer (b) are copolymerized to form a random copolymer, the monomer (c) is added, and a crosslinking monomer (c) is added to the polymerization terminal of the random copolymer. ) In order, a liquid crystal polymer partially having a block structure portion can be obtained. Further, after the crosslinkable monomer (c) is polymerized to form the block body c, the liquid crystal monomer (a) and the non-liquid crystal monomer (b) are added, and the liquid crystal monomer (a) and the polymer terminal of the block body c are added. The non-liquid crystal monomer (b) may be randomly copolymerized. In the case of normal radical polymerization, examples of the polymerization initiator include azo initiators such as AIBN (azobisisobutyronitrile) and peroxide initiators such as BPO (benzoyl peroxide). The amount of the polymerization initiator is usually about 0.1 to 10 parts by weight with respect to 100 parts by weight of the monomer. The polymerization temperature varies depending on the type of polymerization initiator, but is usually about 40 to 80 ° C.

  The number average molecular weight of the block type liquid crystal polymer is preferably about 2,000 to 100,000. Preferably it is about 5,000 to 50,000. If the number average molecular weight is too high, it takes a long time to polymerize, and it is difficult to handle because it is difficult to dissolve in a solvent. Moreover, it becomes difficult to orient. The number average molecular weight is a value in terms of polystyrene by GPC (gel permeation chromatography).

  The polymerization temperature is preferably about 60 to 120 ° C. from the polymerization rate, the catalyst deactivation temperature, and the solubility of the monomer in the solvent. The polymerization time depends on the final number average molecular weight and polymerization temperature, but it is preferable to complete the polymerization in about 3 to 100 hours.

  The block type liquid crystal polymer of the present invention can be used as a liquid crystal polymer composition containing a reaction aid relating to the functional group of the crosslinkable monomer (c).

  The block liquid crystal polymer can be crosslinked by reacting the functional groups of the crosslinkable monomer (c) with each other in the presence of a reaction aid related to the functional group. For example, when the crosslinkable monomer (c) is a monomer having an epoxy group or a monomer having a hydroxyl group, an ultraviolet cation initiator is suitably used as a reaction aid. The ultraviolet cation initiator generates an acid and reacts an epoxy group and a hydroxyl group under irradiation of ultraviolet rays.

As the UV cationic initiator, ArN ₂ ⁺ Q ⁻ , Y ₃ S ⁺ Q ⁻ or Y ₂ I ⁺ Q ⁻ [wherein Ar is an aryl group such as a bis (dodecylphenyl) group, Y is an alkyl group or the same as above aryl group, Q ^- is ^{_{BF 4 -, PF 6 -,}} AsF 6 -, SbF 6 -, SbCl 6 -, HSO 4 -, represented by Cl is non-basic and nucleophilic anions such as] Diazonium salts, sulfonium salts, iodonium salts and the like are preferably used. Specifically, bis (dodecylphenyl) iodonium hexafluoroantimonate, bis (t-butylphenyl) iodonium hexafluorophosphate, bis (t-butylphenyl) iodonium trifluoromethanesulfonate, triphenylsulfate Examples thereof include onium / trifluoromethanesulfonate, biphenyliodonium / trifluoromethanesulfonate, phenyl- (3-hydroxy-pentadecylphenyl) iodonium / hexafluoroantimonate, and compounds containing these components. Various mixtures comprising the above components, for example, “UV-9380C” manufactured by Toshiba Silicone Co., Ltd., which is a chemical product containing 45% by weight of bis (dodecylphenyl) iodonium hexafluoroantimonate, etc. it can.

  These reaction aids such as ultraviolet cation initiators preferably contain 0.01 to 20 parts by weight with respect to 100 parts by weight of the block type liquid crystal polymer. Preferably it is 0.05-10 weight part, More preferably, it is 0.1-5 weight part. When the blending amount of the reaction aid is less than 0.01 parts by weight, crosslinking is insufficient. On the other hand, when it exceeds 20 parts by weight, there is a risk of excessive crosslinking.

  In addition to a reaction aid such as an ultraviolet cation initiator, a polyfunctional epoxy compound can be used in combination as a crosslinking aid. Examples of the epoxy compound include trifunctional epoxy compounds such as epoxidized 3-cyclohexene-1,2-dicarboxylate bis (3-cyclohexenylmethyl) modified ε-caprolactone, epoxidized butanetetracarboxylic acid tetrakis- (3-cyclo Hexenylmethyl) -modified ε-caprolactone and other tetrafunctional epoxy compounds. These crosslinking aids are preferably used in a proportion of 10 parts by weight or less with respect to 100 parts by weight of the block type liquid crystal polymer.

  The block type liquid crystal polymer of the present invention can be used for a liquid crystal polymer composition containing a crosslinking agent having at least two functional groups having reactivity with respect to the functional group of the monomer (c).

  The block liquid crystal polymer can be cross-linked by reacting the functional group of the monomer (c) with a cross-linking agent. The combination of these functional groups is not particularly limited as long as it has reactivity. For example, when the functional group of the monomer (c) is a hydroxyl group, examples of the functional group of the crosslinking agent include an isocyanate group, a carboxyl group, and an epoxy group. Further, when the functional group of the monomer (c) is an epoxy group, examples of the functional group of the crosslinking agent include a carboxyl group, a hydroxyl group, and an amino group. Further, when the functional group of the monomer (c) is a carboxyl group, examples of the functional group of the crosslinking agent include a hydroxyl group, an amino group, an isocyanate group, an epoxy group, and an aziridine group. Among these combinations, it is preferable that the functional group of the monomer (c) is a hydroxyl group and the functional group of the crosslinking agent is an isocyanate group.

  These crosslinking agents preferably contain 0.01 to 20 parts by weight with respect to 100 parts by weight of the block type liquid crystal polymer. Preferably it is 0.05-10 weight part, More preferably, it is 0.1-5 weight part. When the blending amount of the crosslinking agent is less than 0.01 parts by weight, crosslinking is insufficient. On the other hand, when it exceeds 20 parts by weight, there is a risk of excessive crosslinking.

  A polyfunctional monomer can be used in combination with the liquid crystal polymer composition. Examples of the polyfunctional monomer include tripropylene glycol diacrylate, ethylene glycol diacrylate, trimethylolpropane triacrylate, pentaerythritol triacrylate, dipentaerythritol pentaacrylate, dipentaerythritol hexaacrylate, dimethylolpropane tetraacrylate, and the like. It is done. The blending amount of these polyfunctional monomers is usually preferably 10 parts by weight or less per 100 parts by weight of the block type liquid crystal polymer.

  When an alkyl (meth) acrylate having an alkyl group having 1 to 11 carbon atoms is used as the crosslinkable monomer (c), it is preferable to add a radical generator to the liquid crystal polymer composition. A polyfunctional radical generator is used as the radical generator. Examples of the polyfunctional radical generator include 2- (p-methoxyphenyl) -4,6-bis (trichloromethyl) -s-triazine, 2-phenyl-4,6-bis (trichloromethyl) -s-triazine. 2- (4′-methoxy-1′-naphthyl) -4,6-bis (trichloromethyl) -s-triazine, 2,4-trichloromethyl- (4′-methoxyphenyl) -6-triazine, 2, Trichloro such as 4-trichloromethyl (4'-methoxynaphthyl) -6-triazine, 2,4-trichloromethyl (piperonyl) -6-triazine, 2,4-trichloromethyl (4'-methoxystyryl) -6-triazine And methyl group-containing triazine derivatives. In addition, an oligomer type polyfunctional radical generator such as oligo [2-hydroxy-2-methyl-1- [4- (1-methylvinyl) phenyl] propane] can be used.

  The blending amount of the radical generator is usually preferably 5 parts by weight or less per 100 parts by weight of the block type liquid crystal polymer. More preferably, it is 0.1-5 weight part, More preferably, it is 0.4-1 weight part. When the blending amount of the radical generator is less than 0.1 parts by weight, the crosslinkability becomes poor. On the other hand, if it exceeds 5 parts by weight, there is a risk of excessive crosslinking.

  Along with the radical generator, a benzophenone derivative (benzophenone or a derivative thereof) can be mixed as a crosslinking aid. When this cross-linking aid is mixed, the surface layer can be cross-linked and cured more quickly, whereby the phenomenon of inhibiting the cross-linking and curing reaction due to oxygen in the surface layer is suppressed, and the cross-linking and curing can be performed uniformly in the thickness direction. The amount of the benzophenone derivative used is 3 parts by weight or less, usually 0.1 to 3 parts by weight, and preferably 0.5 to 1 part by weight per 100 parts by weight of the block type liquid crystal polymer.

  Moreover, various additives can be mix | blended with the block type liquid crystal polymer and liquid crystal polymer composition of this invention in the range which does not affect a characteristic.

  By applying the block type liquid crystal polymer or the liquid crystal polymer composition on a substrate and forming a film, a vertically aligned liquid crystal film is obtained. In addition, an inclined alignment film can be obtained by applying the block type liquid crystal polymer or liquid crystal polymer composition on a substrate having an alignment regulating force in the horizontal direction and aligning it to form a film.

  The coating method on the substrate is not particularly limited, and either a melting method or a solution method may be adopted, but a solution method is preferable. Coating on the substrate can be performed with an appropriate coating machine such as a bar coater, a spinner, or a roll coater, but the casting method is preferable from the viewpoint of the quality of the film formation surface.

  Examples of the solvent for dissolving the block type liquid crystal polymer in the solution coating include halogenated hydrocarbons such as chloroform, dichloromethane, dichloroethane, tetrachloroethane, trichloroethylene, tetrachloroethylene, and chlorobenzene, and phenols such as phenol and parachlorophenol. , Aromatic hydrocarbons such as benzene, toluene, xylene, methoxybenzene, 1,2-dimethoxybenzene, etc., acetone, ethyl acetate, tert-butyl alcohol, glycerin, ethylene glycol, triethylene glycol, ethylene bricol monomethyl Ether, diethylene glycol dimethyl ether, ethyl cellosolve, butyl cellosolve, 2-pyrrolidone, N-methyl-2-pyrrolidone, pyridine, triethyl alcohol Emissions, tetrahydrofuran, dimethylformamide, dimethylacetamide, dimethyl sulfoxide, acetonitrile, butyronitrile, carbon disulfide, methyl ethyl ketone, cyclohexanone, cyclopentanone and the like are preferable. The concentration of the solution is usually about 3 to 50% by weight.

  A conventionally known substrate can be used as the alignment substrate. For example, a thin film made of polyimide, polyvinyl alcohol or the like is formed on a substrate, and a rubbing film obtained by rubbing it with a rayon cloth, a polymer having a photocrosslinking group such as cinnamate or azobenzene, or photo-alignment by irradiating polarized ultraviolet rays on polyimide A film, a stretched film, or the like is used. As the stretched film, a substrate having orientation such as stretched polyethylene terephthalate can be used as it is as an oriented substrate. In addition, it can also be oriented by magnetic field, electric field orientation, and shear stress manipulation.

  As the substrate, polyethylene terephthalate, triacetyl cellulose, norbornene resin, polyvinyl alcohol, polyimide, polyarylate, polycarbonate, a film made of plastic such as polysulfone or polyethersulfone, a glass plate, and a quartz sheet are used.

  The alignment is performed at a temperature higher than the liquid crystal transition temperature of the liquid crystal polymer. The alignment temperature and time are appropriately determined according to the type of liquid crystal polymer.

  The solution of the liquid crystal polymer or the like is formed into a dry film while maintaining the liquid crystal state by alignment. The drying temperature may be a temperature not lower than the boiling point of the solvent. Dry film formation can be performed together with the alignment step. When performing dry film formation together with the alignment step, the temperature is set according to the type of the solvent and the liquid crystal polymer. In the case of a liquid crystal polymer composition, a film is formed by performing a crosslinking treatment after alignment. The crosslinking treatment can be performed by heat treatment, ultraviolet irradiation, electron beam irradiation or the like depending on the type of the liquid crystal polymer composition. Crosslinking treatments can also be combined.

  The alignment temperature varies depending on the type of the liquid crystal polymer and the base material, and thus cannot be generally specified, but is usually 60 to 300 ° C., preferably 70 to 200 ° C. The alignment treatment time varies depending on the temperature and the type of the liquid crystal polymer and the substrate, and cannot be generally specified, but is usually selected in the range of 10 seconds to 2 hours, preferably 20 seconds to 30 minutes.

  After the alignment treatment, a cooling operation is performed. The cooling operation can be performed by taking out the film formed on the alignment substrate after the heat treatment from room temperature in the heat treatment operation to room temperature. Moreover, you may perform forced cooling, such as air cooling and water cooling. The alignment of the liquid crystal layer or tilted alignment layer formed of the liquid crystal polymer or liquid crystal polymer composition is fixed by cooling to a temperature lower than the glass transition temperature of the liquid crystal polymer.

  Next, the liquid crystal layer and the tilted alignment layer are irradiated with radiation, and the liquid crystal polymer is fixed by crosslinking and curing to obtain a liquid crystal film or a tilted alignment film having a high surface hardness. Irradiation is performed by, for example, ultraviolet irradiation. An electron beam can also be used as the radiation. At the time of radiation irradiation, crosslinking can be promoted by heating and radioactive irradiation.

The ultraviolet irradiation conditions are preferably in an inert gas atmosphere in order to sufficiently promote the reaction. Usually, a high-pressure mercury ultraviolet lamp having an illuminance of about 0.1 to 10 J / cm ² is typically used. Different types of lamps such as metahalide UV lamps and incandescent tubes can also be used. It should be noted that the surface temperature of the liquid crystal layer or the like at the time of ultraviolet irradiation is appropriately adjusted by, for example, a cold mirror, water cooling or other cooling treatment, or increasing the line speed.

  In this way, a liquid crystal film and a tilted alignment film are obtained. The thickness of the liquid crystal film is not particularly limited, but is preferably 200 μm or less. The thickness of the tilted alignment film is not particularly limited, but is usually about 1 to 100 μm, preferably 1 to 10 μm.

  The liquid crystal film and the tilted alignment film may be used without being peeled from the substrate, or may be peeled from the substrate. A liquid crystal film or a tilted alignment film can be used alone as a retardation plate, a viewing angle compensation film, an optical compensation film, or in combination with other optical films.

  An example of the optical film is a polarizing plate. A polarizing plate having a transparent protective film on one or both sides of a polarizer is generally used.

  The polarizer is not particularly limited, and various types can be used. Examples of the polarizer include hydrophilic polymer films such as polyvinyl alcohol film, partially formalized polyvinyl alcohol film, and ethylene / vinyl acetate copolymer partially saponified film, and two colors such as iodine and dichroic dye. Examples thereof include polyene-based oriented films such as those obtained by adsorbing volatile substances and uniaxially stretched, polyvinyl alcohol dehydrated products and polyvinyl chloride dehydrochlorinated products. Among these, a polarizer composed of a polyvinyl alcohol film and a dichroic material such as iodine is preferable. 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 with dirt and anti-blocking agents by washing the polyvinyl alcohol film with water, it also has the effect of preventing unevenness such as uneven coloring by swelling the polyvinyl alcohol film. is there. Stretching may be performed after dyeing with iodine, or may be performed while dyeing, or may be performed with dyeing after iodine. The film can be stretched in an aqueous solution of boric acid or potassium iodide or in a water bath.

  As a material for forming the transparent protective film provided on one side or both sides of the polarizer, a material excellent in transparency, mechanical strength, thermal stability, moisture shielding property, isotropy and the like is preferable. For example, polyester polymers such as polyethylene terephthalate and polyethylene naphthalate, cellulose polymers such as diacetyl cellulose and triacetyl cellulose, acrylic polymers such as polymethyl methacrylate, styrene such as polystyrene and acrylonitrile / styrene copolymer (AS resin) -Based polymer, polycarbonate-based polymer and the like. In addition, polyethylene, polypropylene, polyolefins having a cyclo or norbornene structure, polyolefin polymers such as ethylene / propylene copolymers, vinyl chloride polymers, amide polymers such as nylon and aromatic polyamide, imide polymers, sulfone polymers , Polyether sulfone polymer, polyether ether ketone polymer, polyphenylene sulfide polymer, vinyl alcohol polymer, vinylidene chloride polymer, vinyl butyral polymer, arylate polymer, polyoxymethylene polymer, epoxy polymer, or the above Polymer blends and the like are also examples of polymers that form the 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, and silicone.

  Moreover, the polymer film described in JP-A-2001-343529 (WO01 / 37007), for example, (A) a thermoplastic resin having a substituted and / or unsubstituted imide group in the side chain, and (B) a substitution in the side chain And / or a resin composition containing an unsubstituted phenyl and a thermoplastic resin having a nitrile group. A specific example is a film of a resin composition containing an alternating copolymer composed of isobutylene and N-methylmaleimide and an acrylonitrile / styrene copolymer. As the film, a film made of a mixed extruded product of the resin composition or the like can be used.

  Although the thickness of a protective film can be determined suitably, generally it is about 1-500 micrometers from points, such as workability | operativity, such as intensity | strength and handleability, and thin layer property. 1-300 micrometers is especially preferable, and 5-200 micrometers is more preferable.

  Moreover, it is preferable that a protective film has as little color as possible. Therefore, Rth = [(nx + ny) / 2−nz] · d (where nx and ny are the main refractive index in the plane of the film, nz is the refractive index in the film thickness direction, and d is the film thickness). A protective film having a retardation value in the film thickness direction of −90 nm to +75 nm is preferably used. By using a film having a thickness direction retardation value (Rth) of −90 nm to +75 nm, the coloring (optical coloring) of the polarizing plate caused by the protective film can be almost eliminated. The thickness direction retardation value (Rth) is more preferably −80 nm to +60 nm, and particularly preferably −70 nm to +45 nm.

  As the protective film, a cellulose polymer such as triacetyl cellulose is preferable from the viewpoints of polarization characteristics and durability. A triacetyl cellulose film is particularly preferable. In addition, when providing a protective film in the both sides of a polarizer, the protective film which consists of the same polymer material may be used by the front and back, and the protective film which consists of a different polymer material etc. may be used. The polarizer and the protective film are usually in close contact with each other through an aqueous adhesive or the like. Examples of the water-based adhesive include an isocyanate-based adhesive, a polyvinyl alcohol-based adhesive, a gelatin-based adhesive, a vinyl-based latex, a water-based polyurethane, and a water-based polyester.

  The surface of the transparent protective film to which the polarizer is not adhered may be subjected to a hard coat layer, an antireflection treatment, an antisticking treatment, or a treatment for diffusion or antiglare.

  The hard coat treatment is applied for the purpose of preventing scratches on the surface of the polarizing plate. For example, a transparent protective film with a cured film excellent in hardness, sliding properties, etc. by an appropriate ultraviolet curable resin such as acrylic or silicone is used. It can be formed by a method of adding to the surface of the film. The antireflection treatment is performed for the purpose of preventing reflection of external light on the surface of the polarizing plate, and can be achieved by forming an antireflection film or the like according to the conventional art. Further, the anti-sticking treatment is performed for the purpose of preventing adhesion with an adjacent layer.

  The anti-glare treatment is applied for the purpose of preventing the outside light from being reflected on the surface of the polarizing plate and obstructing the visibility 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 particles. The fine particles to be included in the formation of the surface fine concavo-convex structure are, for example, conductive materials made of silica, alumina, titania, zirconia, tin oxide, indium oxide, cadmium oxide, antimony oxide or the like having an average particle diameter of 0.5 to 50 μm. In some cases, transparent fine particles such as inorganic fine particles, organic fine particles made of a crosslinked or uncrosslinked polymer, etc. are used. When forming a surface fine uneven structure, the amount of fine particles used is generally about 2 to 50 parts by weight, preferably 5 to 25 parts by weight, based on 100 parts by weight of the transparent resin forming the surface fine uneven structure. 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.

  The antireflection layer, antisticking layer, diffusion layer, antiglare layer, and the like can be provided on the transparent protective film itself, or can be provided separately from the transparent protective film as an optical layer.

  As other optical films, for example, formation of liquid crystal display devices such as reflectors, transflectors, retardation plates (including wavelength plates such as 1/2 and 1/4), viewing angle compensation films, brightness enhancement films, etc. And an optical layer that may be used in the above. These may be laminated on the polarizing plate or the like for practical use, and one layer or two or more layers may be used.

  In particular, a reflective polarizing plate or a semi-transmissive polarizing plate in which a polarizing plate is further laminated with a reflecting plate or a semi-transmissive reflecting plate, an elliptical polarizing plate or a circular polarizing plate in which a retardation plate is further laminated on a polarizing plate, a polarizing plate A wide viewing angle polarizing plate in which a viewing angle compensation film is further laminated on a plate, or a polarizing plate in which a brightness enhancement film is further laminated on a polarizing plate is preferable.

  A reflective polarizing plate is a polarizing plate provided with a reflective layer, and is used to form a liquid crystal display device or the like that reflects incident light from the viewing side (display side). Such a light source can be omitted, and the liquid crystal display device can be easily thinned. The reflective polarizing plate can be formed by an appropriate method such as a method in which a reflective layer made of metal or the like is attached to one surface of the polarizing plate via a transparent protective layer or the like as necessary.

  Specific examples of the reflective polarizing plate include those in which a reflective layer is formed by attaching a foil or a vapor deposition film made of a reflective metal such as aluminum on one side of a transparent protective film matted as necessary. Moreover, the transparent protective film contains fine particles so as to have a surface fine concavo-convex structure and a reflective layer having a fine concavo-convex structure thereon. The reflective layer having the fine concavo-convex structure has an advantage that incident light is diffused by irregular reflection to prevent directivity and glaring appearance and to suppress unevenness in brightness and darkness. The transparent protective film containing fine particles also has an advantage that incident light and its reflected light are diffused when passing through it, and light and dark unevenness can be further suppressed. The reflective layer of the fine concavo-convex structure reflecting the surface fine concavo-convex structure of the transparent protective film is formed by transparent the metal by an appropriate method such as a vapor deposition method such as a vacuum vapor deposition method, an ion plating method, a sputtering method, or a plating method. It can be performed by a method of directly attaching to the surface of the protective layer.

  Instead of the method of directly applying the reflecting plate to the transparent protective film of the polarizing plate, the reflecting plate can be used as a reflecting sheet provided with a reflecting layer on an appropriate film according to the transparent film. Since the reflective layer is usually made of metal, the usage form in which the reflective surface is covered with a transparent protective film, a polarizing plate or the like is used to prevent the reflectance from being lowered due to oxidation, and thus to maintain the initial reflectance for a long time. In addition, it is more preferable to avoid a separate attachment of the protective layer.

  The semi-transmissive polarizing plate can be obtained by using a semi-transmissive reflective layer such as a half mirror that reflects and transmits light with the reflective layer. A transflective polarizing plate is usually provided on the back side of a liquid crystal cell, and displays an image by reflecting incident light from the viewing side (display side) when a liquid crystal display device is used in a relatively bright atmosphere. In a relatively dark atmosphere, a liquid crystal display device or the like that displays an image using a built-in light source such as a backlight built in the back side of the transflective polarizing plate can be formed. In other words, the transflective polarizing plate is useful for forming a liquid crystal display device of a type that can save energy of using a light source such as a backlight in a bright atmosphere and can be used with a built-in light source even in a relatively dark atmosphere. It is.

  An elliptically polarizing plate or a circularly polarizing plate in which a retardation plate is further laminated on a polarizing plate will be described. A phase difference plate or the like is used when changing linearly polarized light to elliptically polarized light or circularly polarized light, changing elliptically polarized light or circularly polarized light to linearly polarized light, or changing the polarization direction of linearly polarized light. In particular, a so-called quarter-wave plate (also referred to as a λ / 4 plate) is used as a retardation plate that changes linearly polarized light into circularly polarized light or changes circularly polarized light into linearly polarized light. A half-wave plate (also referred to as a λ / 2 plate) is usually used when changing the polarization direction of linearly polarized light.

  The elliptically polarizing plate is effectively used for black and white display without the above color by compensating (preventing) the coloration (blue or yellow) generated by the birefringence of the liquid crystal layer of the super twist nematic (STN) type liquid crystal display device. It is done. Further, the one in which the three-dimensional refractive index is controlled is preferable because it can compensate (prevent) coloring that occurs when the screen of the liquid crystal display device is viewed from an oblique direction. The circularly polarizing plate is effectively used, for example, when adjusting the color tone of an image of a reflective liquid crystal display device in which an image is displayed in color, and also has an antireflection function.

  Examples of the retardation plate include a birefringent film obtained by uniaxially or biaxially stretching a polymer material, a liquid crystal polymer alignment film (liquid crystal film), and a liquid crystal polymer alignment layer supported by a film. . The thickness of the retardation film is not particularly limited, but is generally about 20 to 150 μm.

  Examples of the polymer material include polyvinyl alcohol, polyvinyl butyral, polymethyl vinyl ether, polyhydroxyethyl acrylate, hydroxyethyl cellulose, hydroxypropyl cellulose, methyl cellulose, polycarbonate, polyarylate, polysulfone, polyethylene terephthalate, polyethylene naphthalate, polyether sulfone, Polyphenylene sulfide, polyphenylene oxide, polyallylsulfone, polyvinyl alcohol, polyamide, polyimide, polyolefin, polyvinyl chloride, cellulose polymer, norbornene resin, or binary, ternary various copolymers, graft copolymers Examples thereof include polymers and blends. These polymer materials become oriented products (stretched films) by stretching or the like.

  Examples of the liquid crystalline polymer include various main chain types and side chain types in which a conjugated linear atomic group (mesogen) imparting liquid crystal alignment is introduced into the main chain or side chain of the polymer. It is done. Specific examples of the main chain type liquid crystalline polymer include, for example, a nematic orientation polyester-based liquid crystalline polymer, a discotic polymer, and a cholesteric polymer having a structure in which a mesogenic group is bonded to a spacer portion that imparts flexibility. . Specific examples of the side chain type liquid crystalline polymer include polysiloxane, polyacrylate, polymethacrylate, or polymalonate as a main chain skeleton, and a nematic alignment imparting paraffin through a spacer portion composed of a conjugated atomic group as a side chain. Examples thereof include those having a mesogen moiety composed of a substituted cyclic compound unit. These liquid crystalline polymers are prepared by, for example, applying a solution of a liquid crystalline polymer on an alignment surface such as those obtained by rubbing the surface of a thin film such as polyimide or polyvinyl alcohol formed on a glass plate, or by obliquely depositing silicon oxide. This is done by developing and heat treatment.

  The retardation plate may have an appropriate retardation according to the purpose of use, such as those for the purpose of compensating for various wavelength plates or birefringence of the liquid crystal layer, viewing angle, and the like. What laminated | stacked the phase difference plate and controlled optical characteristics, such as phase difference, etc. may be used.

  The elliptical polarizing plate and the reflective elliptical polarizing plate are obtained by laminating a polarizing plate or a reflective polarizing plate and a retardation plate in an appropriate combination. Such an elliptically polarizing plate or the like can also be formed by sequentially laminating them separately in the manufacturing process of the liquid crystal display device so as to be a combination of a (reflection type) polarizing plate and a retardation plate. As described above, an optical film such as an elliptically polarizing plate has an advantage that it can improve the production efficiency of a liquid crystal display device and the like because of its excellent quality stability and lamination workability.

  The viewing angle compensation film is a film for widening the viewing angle so that an image can be seen relatively clearly even when the screen of the liquid crystal display device is viewed from a slightly oblique direction rather than perpendicular to the screen. As such a viewing angle compensation phase difference plate, for example, a phase difference plate, an alignment film such as a liquid crystal polymer, or an alignment layer such as a liquid crystal polymer supported on a transparent substrate is used. A normal retardation plate uses a birefringent polymer film uniaxially stretched in the plane direction, whereas a retardation plate used as a viewing angle compensation film stretches biaxially in the plane direction. Birefringent polymer film, biaxially stretched film such as polymer with birefringence with a controlled refractive index in the thickness direction that is uniaxially stretched in the plane direction and stretched in the thickness direction, etc. Used. Examples of the inclined alignment film include a film obtained by bonding a heat shrink film to a polymer film and stretching or / and shrinking the polymer film under the action of the contraction force by heating, and a film obtained by obliquely aligning a liquid crystal polymer. Can be mentioned. The raw material polymer for the phase difference plate is the same as the polymer described in the previous phase difference plate, preventing coloration due to a change in the viewing angle based on the phase difference by the liquid crystal cell and expanding the viewing angle for good visual recognition. An appropriate one for the purpose can be used.

  Also, from the viewpoint of achieving a wide viewing angle with good visibility, an optically compensated phase difference in which a liquid crystal polymer alignment layer, in particular an optically anisotropic layer composed of a discotic liquid crystal polymer gradient alignment layer, is supported by a triacetylcellulose film. A plate can be preferably used.

  A polarizing plate obtained by bonding a polarizing plate and a brightness enhancement film is usually provided on the back side of a liquid crystal cell. The brightness enhancement film reflects a linearly polarized light with a predetermined polarization axis or a circularly polarized light in a predetermined direction when natural light is incident due to a backlight such as a liquid crystal display device or reflection from the back side, and transmits other light. In addition, a polarizing plate in which a brightness enhancement film is laminated with a polarizing plate allows light from a light source such as a backlight to enter to obtain transmitted light in a predetermined polarization state, and reflects light without transmitting the light other than the predetermined polarization state. The The light reflected on the surface of the brightness enhancement film is further inverted through a reflective layer or the like provided behind the brightness enhancement film and re-incident on the brightness enhancement film, and part or all of the light is transmitted as light having a predetermined polarization state. Luminance can be improved by increasing the amount of light transmitted through the enhancement film and increasing the amount of light that can be used for liquid crystal display image display or the like by supplying polarized light that is difficult to be absorbed by the polarizer. That is, when light is incident through the polarizer from the back side of the liquid crystal cell without using a brightness enhancement film, light having a polarization direction that does not coincide with the polarization axis of the polarizer is almost polarized. It is absorbed by the polarizer and does not pass through the polarizer. That is, although depending on the characteristics of the polarizer used, approximately 50% of the light is absorbed by the polarizer, and the amount of light that can be used for liquid crystal image display or the like is reduced accordingly, resulting in a dark image. The brightness enhancement film allows light having a polarization direction that is absorbed by the polarizer to be reflected once by the brightness enhancement film without being incident on the polarizer, and further inverted through a reflective layer provided on the rear side thereof. Repeatedly re-enter the brightness enhancement film, and the brightness enhancement film transmits only polarized light whose polarization direction is such that the polarization direction of light reflected and inverted between the two can pass through the polarizer. Therefore, light such as a backlight can be efficiently used for displaying an image on the liquid crystal display device, and the screen can be brightened.

  A diffusion plate may be provided between the brightness enhancement film and the reflective layer. The polarized light reflected by the brightness enhancement film is directed to the reflective layer or the like, but the installed diffuser plate uniformly diffuses the light passing therethrough and simultaneously cancels the polarized state and becomes a non-polarized state. That is, the diffuser plate returns the polarized light to the original natural light state. The light in the non-polarized state, that is, the natural light state is directed toward the reflection layer and the like, reflected through the reflection layer and the like, and again passes through the diffusion plate and reenters the brightness enhancement film. Thus, while maintaining the brightness of the display screen by providing a diffuser plate that returns polarized light to the original natural light state between the brightness enhancement film and the reflective layer, etc., the brightness unevenness of the display screen is reduced at the same time, A uniform and bright screen can be provided. By providing such a diffuser plate, it is considered that the first incident light has a moderate increase in the number of repetitions of reflection, and in combination with the diffusion function of the diffuser plate, a uniform bright display screen can be provided.

  The brightness enhancement film has a characteristic of transmitting linearly polarized light having a predetermined polarization axis and reflecting other light, such as a multilayer thin film of dielectric material or a multilayer laminate of thin film films having different refractive index anisotropies. Such as an alignment film of a cholesteric liquid crystal polymer or an alignment liquid crystal layer supported on a film substrate, which reflects either left-handed or right-handed circularly polarized light and transmits other light. Appropriate things such as a thing can be used.

  Therefore, in the brightness enhancement film of the type that transmits linearly polarized light having the predetermined polarization axis as described above, the transmitted light is incident on the polarizing plate with the polarization axis aligned as it is, thereby efficiently transmitting while suppressing absorption loss due to the polarizing plate. Can be made. On the other hand, in a brightness enhancement film of a type that emits circularly polarized light such as a cholesteric liquid crystal layer, it can be directly incident on a polarizer. However, from the viewpoint of suppressing absorption loss, the circularly polarized light is linearly polarized through a retardation plate. It is preferable to make it enter into a polarizing plate. Note that circularly polarized light can be converted to linearly polarized light by using a quarter wave plate as the retardation plate.

  A retardation plate that functions as a quarter-wave plate in a wide wavelength range such as a visible light region exhibits, for example, a retardation layer that functions as a quarter-wave plate for light-color light having a wavelength of 550 nm and other retardation characteristics. It can be obtained by a method of superposing a retardation layer, for example, a retardation layer functioning as a half-wave plate. Therefore, the retardation plate disposed between the polarizing plate and the brightness enhancement film may be composed of one or more retardation layers.

  In addition, the cholesteric liquid crystal layer can also be obtained by reflecting circularly polarized light in a wide wavelength range such as a visible light region by combining two or more layers having different reflection wavelengths and having an overlapping structure. Based on this, transmitted circularly polarized light in a wide wavelength range can be obtained.

  Further, the polarizing plate may be formed by laminating a polarizing plate and two or three or more optical layers like the above-described polarization separation type polarizing plate. Therefore, a reflective elliptical polarizing plate or a semi-transmissive elliptical polarizing plate in which the above-mentioned reflective polarizing plate or transflective polarizing plate and a retardation plate are combined may be used.

  An optical film in which the optical layer is laminated on a polarizing plate can be formed by a method of sequentially laminating separately in the manufacturing process of a liquid crystal display device or the like. There is an advantage that the manufacturing process of the liquid crystal display device and the like can be improved. For the lamination, an appropriate adhesive means such as an adhesive layer can be used. When adhering the polarizing plate and the other optical layer, their optical axes can be set at an appropriate arrangement angle in accordance with the target phase difference characteristic.

  In addition, each layer such as the optical film or the pressure-sensitive adhesive layer of the present invention is treated with an ultraviolet absorber such as a salicylic acid ester compound, a benzophenol compound, a benzotriazole compound, a cyanoacrylate compound, or a nickel complex compound. It may be one having an ultraviolet absorbing ability by a method such as a method.

  The optical film of the present invention can be preferably used for forming various image display devices such as a liquid crystal display device. The liquid crystal display device can be formed according to the conventional method. In other words, a liquid crystal display device is generally formed by appropriately assembling components such as a liquid crystal cell, an optical film, and an illumination system as necessary, and incorporating a drive circuit. There is no limitation in particular except the point which uses a film, and it can apply according to the former. As the liquid crystal cell, any type such as a TN type, an STN type, or a π type can be used.

  An appropriate liquid crystal display device such as a liquid crystal display device in which an adhesive optical film is disposed on one side or both sides of a liquid crystal cell, or a backlight or a reflector used in an illumination system can be formed. In that case, the optical film according to the present invention can be installed on one side or both sides of the liquid crystal cell. When providing an optical film on both sides, they may be the same or different. Further, when forming a liquid crystal display device, for example, a single layer or a suitable part such as a diffusing plate, an antiglare layer, an antireflection film, a protective plate, a prism array, a lens array sheet, a light diffusing plate, a backlight, etc. Two or more layers can be arranged.

  Next, an organic electroluminescence device (organic EL display device) will be described. Generally, in an organic EL display device, a transparent electrode, an organic light emitting layer, and a metal electrode are sequentially laminated on a transparent substrate to form a light emitter (organic electroluminescent light emitter). Here, the organic light emitting layer is a laminate of various organic thin films, for example, a laminate of a hole injection layer made of a triphenylamine derivative and the like and a light emitting layer made of a fluorescent organic solid such as anthracene, Alternatively, a structure having various combinations such as a laminate of such a light emitting layer and an electron injection layer composed of a perylene derivative or the like, or a laminate of these hole injection layer, light emitting layer, and electron injection layer is known. It has been.

  In organic EL display devices, holes and electrons are injected into the organic light-emitting layer by applying a voltage to the transparent electrode and the metal electrode, and the energy generated by recombination of these holes and electrons excites the phosphor material. Then, light is emitted on the principle that the excited fluorescent material emits light when returning to the ground state. The mechanism of recombination in the middle is the same as that of a general diode, and as can be predicted from this, the current and the emission intensity show strong nonlinearity with rectification with respect to the applied voltage.

  In an organic EL display device, in order to extract light emitted from the organic light emitting layer, at least one of the electrodes must be transparent, and a transparent electrode usually formed of a transparent conductor such as indium tin oxide (ITO) is used as an anode. It is used as On the other hand, in order to facilitate electron injection and increase luminous efficiency, it is important to use a material having a small work function for the cathode, and usually metal electrodes such as Mg—Ag and Al—Li are used.

  In the organic EL display device having such a configuration, the organic light emitting layer is formed of a very thin film having a thickness of about 10 nm. For this reason, the organic light emitting layer transmits light almost completely like the transparent electrode. As a result, light that is incident from the surface of the transparent substrate at the time of non-light emission, passes through the transparent electrode and the organic light emitting layer, and is reflected by the metal electrode is again emitted to the surface side of the transparent substrate. The display surface of the organic EL display device looks like a mirror surface.

  In an organic EL display device comprising an organic electroluminescent light emitting device comprising a transparent electrode on the surface side of an organic light emitting layer that emits light upon application of a voltage and a metal electrode on the back side of the organic light emitting layer, the surface of the transparent electrode While providing a polarizing plate on the side, a retardation plate can be provided between the transparent electrode and the polarizing plate.

  Since the retardation plate and the polarizing plate have a function of polarizing light incident from the outside and reflected by the metal electrode, there is an effect that the mirror surface of the metal electrode is not visually recognized by the polarization action. In particular, the mirror surface of the metal electrode can be completely shielded by configuring the retardation plate with a quarter-wave plate and adjusting the angle formed by the polarization direction of the polarizing plate and the retardation plate to π / 4. .

  That is, only the linearly polarized light component of the external light incident on the organic EL display device is transmitted by the polarizing plate. This linearly polarized light becomes generally elliptically polarized light by the phase difference plate, but becomes circularly polarized light especially when the phase difference plate is a quarter wave plate and the angle between the polarization direction of the polarizing plate and the phase difference plate is π / 4. .

  This circularly polarized light is transmitted through the transparent substrate, the transparent electrode, and the organic thin film, is reflected by the metal electrode, is again transmitted through the organic thin film, the transparent electrode, and the transparent substrate, and becomes linearly polarized light again on the retardation plate. And since this linearly polarized light is orthogonal to the polarization direction of a polarizing plate, it cannot permeate | transmit a polarizing plate. As a result, the mirror surface of the metal electrode can be completely shielded.

Examples of the present invention will be described below in more detail, but the present invention is not limited thereto. The number average molecular weight of the liquid crystal polymer was measured by the following method.
(Measurement of number average molecular weight)
The prepared liquid crystal polymer was dissolved in THF at 0.1 wt%, and the number average molecular weight was measured by polystyrene conversion using GPC (gel permeation chromatography). Detailed measurement conditions are as follows.
GPC device: Tosoh HLC-8120GPC
Column: manufactured by Tosoh Corporation, (GMH _HR −H) + (GMH _HR −H) + (G2000H _HR )
Flow rate: 0.8ml / min
Concentration: 0.1 wt%
Injection volume: 100 μl
Column temperature: 40 ° C
Eluent: THF

Example 1
2-ethylhexyl acrylate (10 g), 2,2'-bipyridine (2.34 g), and dimethylacetamide (23.3 g) were added to a four-necked flask equipped with a mechanical stirrer, nitrogen introduction tube, cooling tube, and rubber septum. In addition, the system was purged with nitrogen for 2 hours. Under a nitrogen stream, copper bromide (0.72 g) and ethyl 2-bromo-isobutyrate (0.98 g) were added thereto, and a polymerization reaction was performed at 80 ° C. for 2 hours. And it confirmed that the polymerization rate became 80% or more. Then, a solution in which octadecyl acrylate (10 g) and nematic liquid crystal monomer (30 g) of the following general formula (a1-1) were dissolved in dimethylacetamide (93.3 g) by heating and substituted with nitrogen was added, and polymerized at 80 ° C. for 40 hours. Reacted.

その後、反応物をメタノール中に加えて再沈、洗浄を行って精製したブロック型液晶ポリマーを得た。得られたブロック型液晶ポリマーの数平均分子量は９８００であった。

Thereafter, the reaction product was added to methanol for reprecipitation and washing to obtain a purified block liquid crystal polymer. The number average molecular weight of the obtained block type liquid crystal polymer was 9,800.

  The resulting block-type liquid crystal polymer (100 parts by weight) and 2- (p-methoxyphenyl) -4,6-bis (trichloromethyl) -s-triazine (2 parts by weight) as a polyfunctional radical generator A liquid crystal polymer composition was obtained by dissolving in non-900 parts by weight.

A 5% aqueous solution of polyvinyl alcohol (PVA) was applied to a glass plate and dried at 170 ° C., and the PVA surface was rubbed in a certain direction with a rayon cloth to obtain a PVA rubbing film. The liquid crystal polymer composition was applied onto the PVA rubbing film with a spin coater so that the thickness after drying was 1 μm, and the film was oriented by heating and drying at 90 ° C. for 2 minutes. Thereafter, while heating at 110 ° C., irradiation with 5 J / cm ² of ultraviolet rays was performed for crosslinking to obtain a tilted liquid crystal film (tilted alignment film).

Example 2
Add butyl methacrylate (10 g), 2,2'-bipyridine (2.34 g), and dimethylacetamide (23.3 g) to a four-necked flask equipped with a mechanical stirrer, nitrogen inlet tube, condenser tube, and rubber septum. The system was purged with nitrogen for 2 hours. Under a nitrogen stream, copper bromide (0.72 g) and ethyl 2-bromo-isobutyrate (0.98 g) were added thereto, and a polymerization reaction was performed at 80 ° C. for 2 hours. And it confirmed that the polymerization rate became 80% or more. Thereafter, a solution obtained by dissolving octadecyl acrylate (10 g) in dimethylacetamide (23.3 g) by heating and replacing with nitrogen was added, and a polymerization reaction was performed at 80 ° C. for 4 hours. After confirming that the polymerization rate reached 80% or more, a solution in which the nematic liquid crystal monomer (30 g) of the general formula (a1-1) was dissolved in dimethylacetamide (70 g) by heating and replaced with nitrogen was added. The polymerization reaction was conducted at 80 ° C. for 40 hours. Thereafter, the reaction product was added to methanol for reprecipitation and washing to obtain a purified block liquid crystal polymer. The number average molecular weight of the obtained block type liquid crystal polymer was 9,900. Thereafter, a liquid crystal polymer composition was prepared in the same manner as in Example 1 to prepare a liquid crystal film.

Example 3
A four-necked flask equipped with a mechanical stirrer, nitrogen introducing tube, cooling tube, and rubber septum was mixed with octadecyl acrylate (10 g), nematic liquid crystal monomer (30 g) of the above general formula (a1-1), 2,2′-bipyridine ( 2.34 g) and dimethylacetamide (93.3 g) were added, and the system was purged with nitrogen for 2 hours. Under a nitrogen stream, copper bromide (0.72 g) and ethylene bis (2-bromo-2-methylpropionate) (1.8 g) were added thereto, and a polymerization reaction was carried out at 80 ° C. for 24 hours. And after confirming that the polymerization rate became 80% or more, butyl acrylate (10 g) was added, and a polymerization reaction was carried out at 80 ° C. for 5 hours. Thereafter, the reaction product was added to methanol for reprecipitation and washing to obtain a purified block liquid crystal polymer. The number average molecular weight of the obtained block type liquid crystal polymer was 9,800. Thereafter, a liquid crystal polymer composition was prepared in the same manner as in Example 1 to prepare a liquid crystal film.

Example 4
In a four-necked flask equipped with a mechanical stirrer, nitrogen inlet tube, condenser tube, and rubber septum, 3,4-epoxycyclohexylmethyl acrylate (10 g), 2,2′-bipyridine (2.34 g), and dimethylacetamide (23 .3 g) was added and the system was purged with nitrogen for 2 hours. Under a nitrogen stream, copper bromide (0.72 g) and ethyl 2-bromo-isobutyrate (0.98 g) were added thereto, and a polymerization reaction was performed at 80 ° C. for 2 hours. And it confirmed that the polymerization rate became 80% or more. Thereafter, octadecyl acrylate (10 g) and a nematic liquid crystal monomer of the above general formula (a1-1) (30 g) were dissolved in dimethylacetamide (93.3 g) with heating and purged with nitrogen, and polymerized at 80 ° C. for 40 hours. Reacted. Thereafter, the reaction product was added to methanol for reprecipitation and washing to obtain a purified block liquid crystal polymer. The number average molecular weight of the obtained block type liquid crystal polymer was 9700.

  The resulting block type liquid crystal polymer (100 parts by weight) and UV9380C (3 parts by weight) manufactured by Asahi Denka as an ultraviolet cation initiator were dissolved in 900 parts by weight of cyclopentanone to obtain a liquid crystal polymer composition.

On the PVA rubbing film, the liquid crystal polymer composition was applied with a spin coater so that the thickness after drying was 1 μm, and dried by heating at 90 ° C. for 2 minutes to align the film. Thereafter, while heating at 110 ° C., irradiation with 5 J / cm ² of ultraviolet rays was performed for crosslinking to obtain a tilted liquid crystal film.

Example 5
In a four-necked flask equipped with a mechanical stirrer, nitrogen introduction tube, cooling tube, and rubber septum, 6-hydroxyhexyl acrylate (10 g), 2,2'-bipyridine (2.34 g), and dimethylacetamide (23.3 g) Then, the system was purged with nitrogen for 2 hours. Under a nitrogen stream, copper bromide (0.72 g) and ethyl 2-bromo-isobutyrate (0.98 g) were added thereto, and a polymerization reaction was performed at 80 ° C. for 2 hours. And it confirmed that the polymerization rate became 80% or more. Thereafter, octadecyl acrylate (10 g) and a nematic liquid crystal monomer of the above general formula (a1-1) (30 g) were dissolved in dimethylacetamide (93.3 g) with heating and purged with nitrogen, and polymerized at 80 ° C. for 40 hours. Reacted. Thereafter, the reaction product was added to methanol for reprecipitation and washing to obtain a purified block liquid crystal polymer. The number average molecular weight of the obtained block type liquid crystal polymer was 9,800.

  The resulting block type liquid crystal polymer (100 parts by weight) and UV9380C (3 parts by weight) manufactured by Asahi Denka as an ultraviolet cation initiator were dissolved in 900 parts by weight of cyclopentanone to obtain a liquid crystal polymer composition.

On the PVA rubbing film, the liquid crystal polymer composition was applied with a spin coater so that the thickness after drying was 1 μm, and dried by heating at 90 ° C. for 2 minutes to align the film. Thereafter, while heating at 110 ° C., irradiation with 5 J / cm ² of ultraviolet rays was performed for crosslinking to obtain a tilted liquid crystal film.

Comparative Example 1
A four-necked flask equipped with a mechanical stirrer, a nitrogen introduction tube, a cooling tube, and a rubber septum is mixed with octadecyl methacrylate (12.5 g), nematic liquid crystal monomer of the general formula (a1-1) (37.5 g), 2, 2 '-Bipyridine (2.93 g) and dimethylacetamide (167 g) were added and dissolved by heating, and the system was purged with nitrogen for 2 hours. Under a nitrogen stream, copper bromide (0.72 g) and ethyl 2-bromo-isobutyrate (1.22 g) were added thereto, and a polymerization reaction was performed at 80 ° C. for 40 hours. Thereafter, the reaction product was added to methanol for reprecipitation and washing to obtain a purified liquid crystal polymer. The number average molecular weight of the obtained liquid crystal polymer was 7900. Thereafter, a liquid crystal polymer composition was prepared in the same manner as in Example 1 to prepare a liquid crystal film.

Comparative Example 2
Octadecyl methacrylate (12.5 g), 2,2'-bipyridine (2.34 g), and dimethylacetamide (23.3 g) were added to a four-necked flask equipped with a mechanical stirrer, nitrogen introduction tube, cooling tube, and rubber septum. In addition, the system was purged with nitrogen for 2 hours. Under a nitrogen stream, copper bromide (0.9 g) and ethyl 2-bromo-isobutyrate (1.22 g) were added thereto, and a polymerization reaction was performed at 80 ° C. for 2 hours. Then, after confirming that the polymerization rate became 80% or more, the nematic liquid crystal monomer (37.5 g) of the general formula (a1-1) was heated and dissolved in dimethylacetamide (87.5 g) and replaced with nitrogen. The solution was added and a polymerization reaction was carried out at 80 ° C. for 40 hours. Thereafter, the reaction product was added to methanol for reprecipitation and washing to obtain a purified block liquid crystal polymer. The number average molecular weight of the obtained block type liquid crystal polymer was 7,800. Thereafter, a liquid crystal polymer composition was prepared in the same manner as in Example 1 to prepare a liquid crystal film.

Comparative Example 3
A four-necked flask equipped with a mechanical stirrer, a nitrogen introduction tube, a cooling tube, and a rubber septum is mixed with octadecyl methacrylate (10 g), nematic liquid crystal monomer of the general formula (a1-1) (30 g), and 2-ethylhexyl acrylate (10 g). 2,2'-bipyridine (2.34 g) and dimethylacetamide (167 g) were added and dissolved by heating, and the system was purged with nitrogen for 2 hours. Under a nitrogen stream, copper bromide (0.72 g) and ethyl 2-bromo-isobutyrate (0.98 g) were added thereto, and a polymerization reaction was performed at 80 ° C. for 40 hours. Thereafter, the reaction product was added to methanol for reprecipitation and washing to obtain a purified liquid crystal polymer. The number average molecular weight of the obtained liquid crystal polymer was 9900. Thereafter, a liquid crystal polymer composition was prepared in the same manner as in Example 1 to prepare a liquid crystal film.

〔Evaluation methods〕
The following evaluation was performed about the obtained liquid crystal film. The results are shown in Table 1.
(Membrane strength)
The surface of the liquid crystal film was rubbed 3 times with a cloth (Bencot) applied with a load of 10 g / cm ² , and whether or not the surface was scratched was visually confirmed and evaluated under the following conditions.
○: There is almost no scar.
×: Many scars are attached.
(Inclined orientation)
Two polarizing plates were placed in a crossed Nicol state, a liquid crystal film was sandwiched between the two polarizing plates so that the rubbing direction and the absorption axis of one polarizing plate were 45 °, and the front phase difference was observed. . Further, the phase difference was observed by tilting the liquid crystal film left and right about the direction perpendicular to the rubbing direction. Those having a phase difference larger than the front phase difference when tilted to the left or right were judged to be tilted.

表１に示すように、架橋性モノマー（ｃ）単位からなるブロック構造単位を有する液晶ポリマーを液晶フィルム材料として用いることにより、傾斜配向性を維持したまま液晶フィルムの表面硬度を高くすることができる。

As shown in Table 1, by using a liquid crystal polymer having a block structural unit composed of a crosslinkable monomer (c) unit as a liquid crystal film material, the surface hardness of the liquid crystal film can be increased while maintaining the tilt alignment. .

Claims (17)

It has at least a liquid crystal monomer (a) unit, a non-liquid crystal monomer (b) unit having a long-chain alkyl group, and a crosslinkable monomer (c) unit, and at least a block structural unit composed of the crosslinkable monomer (c) unit. A block-type liquid crystal polymer. 2. The block type liquid crystal polymer according to claim 1, wherein a proportion of the block structural unit composed of the crosslinkable monomer (c) unit in the polymer is 10 to 40% by weight. The block type liquid crystal polymer according to claim 1 or 2, wherein the liquid crystal monomer (a) contains a nematic liquid crystal monomer (a1). The nematic liquid crystal monomer (a1) has the general formula (a1):

(Wherein R ¹ represents a hydrogen atom or a methyl group, m represents an integer of 1 to 6, X ¹ represents a —CO ₂ — group, —OCO— group, —CO—, —CH═CH— or —C≡) C-, R ² represents an alkoxy group having 1 to 6 carbon atoms, a cyano group, a fluoro group, or an alkyl group having 1 to 6 carbon atoms, and p and q represent 1 or 2.) 4. The block type liquid crystal polymer according to claim 3, which is a derivative. The block type liquid crystal polymer according to any one of claims 1 to 4, which has a number average molecular weight of 2,000 to 100,000. The block type liquid crystal polymer according to any one of claims 1 to 5, which is obtained by living radical polymerization of each monomer. The block type liquid crystal polymer according to claim 1, wherein the crosslinkable monomer (c) is a monomer having an epoxy group. The block type liquid crystal polymer according to claim 1, wherein the crosslinkable monomer (c) is a monomer having a hydroxyl group. The block type liquid crystal polymer according to any one of claims 1 to 6, wherein the crosslinkable monomer (c) is an alkyl (meth) acrylate having an alkyl group having 1 to 11 carbon atoms. A liquid crystal polymer composition comprising the block type liquid crystal polymer according to claim 7 or 8, and an ultraviolet cation initiator. A liquid crystal polymer composition comprising the block type liquid crystal polymer according to claim 9 and a radical generator. The liquid crystal film obtained by forming into a film the block type liquid crystal polymer in any one of Claims 1-9, or the liquid crystal polymer composition of Claim 10 or 11. The liquid crystal film according to claim 12, wherein the block type liquid crystal polymer forms a crosslinked structure. The block type liquid crystal polymer according to any one of claims 1 to 9, or the liquid crystal polymer composition according to claim 10 or 11, is obtained by aligning on a substrate having an alignment regulating force in a horizontal direction and forming a film. An inclined alignment film. 15. The inclined alignment film according to claim 14, wherein the block type liquid crystal polymer forms a crosslinked structure. An optical film in which at least one optical film is laminated on the liquid crystal film according to claim 12 or 13, or the inclined alignment film according to claim 14 or 15. An image display device using the liquid crystal film according to claim 12 or 13, the inclined alignment film according to claim 14 or 15, or the optical film according to claim 16.