JP2005084278A - Retardation film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a retardation film which is advantageous in productivity and production cost and a manufacturing method therefor. <P>SOLUTION: The retardation film having at least two adjacent optical anisotropic layers containing a liquid-crystalline compound fixed in an alignment state is characterized in that at least one of the two optical anisotropic layers has a negative optical anisotropic layer and an alignment film is absent between the two adjacent optical anisotropic layers. In the manufacturing method for the retardation film, the negative optical anisotropic layer containing the liquid-crystalline compound fixed in the alignment state is formed, then the surface of the formed negative optical anisotropic layer is rubbed and coated with a composition containing a liquid-crystalline compound to form a 2nd optical anisotropic layer. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a retardation film used for various displays (OA devices, reflective and transflective liquid crystal display devices used for portable terminals, etc.), optical disk pickups, and the like.

A retardation plate made of an optically anisotropic material is an indispensable material for an LCD display device. Among these, the optically anisotropic layer having negative optical anisotropy is used for the purpose of correcting positive optical anisotropy and the like (Patent Document 1). Furthermore, when a desired optical performance cannot be achieved in a display device with one type of material, a plurality of optical materials may be used. In such a case, an optical film in which a plurality of optical functional layers are laminated has been proposed in order to reduce the number of members used in the display device and achieve weight reduction, thinning, cost reduction, and the like. For the purpose of performing advanced optical compensation, an optical film in which a liquid crystal layer is laminated has also been proposed (Patent Document 2). When laminating a layer formed of a liquid crystal compound in this way, the first liquid crystal layer (in this specification, “liquid crystal layer” refers to a layer formed using a liquid crystal compound as a raw material, (It does not mean that the layer itself has liquid crystallinity.) An alignment film is applied on the surface, rubbed, and a liquid crystal composition for forming a second liquid crystal layer is applied on the alignment layer, aligned, and laminated. ing. In such a highly functional optical film, it is necessary to separately apply an alignment film in order to form a layer made of a liquid crystalline composition, which is a problem in terms of productivity and cost. It is possible to form the negative optically anisotropic layer with a material other than liquid crystal, but in that case, the film thickness becomes thicker, and the optical performance derived from the weight of the optical member and the film thickness becoming thicker. Problems such as deterioration are likely to occur.
JP-A-11-352328 US Pat. No. 6,160,597

  An object of the present invention is to provide a retardation film having a negative optical anisotropic layer composed of a liquid crystalline compound, which is advantageous in terms of productivity and production cost, and a method for producing the film. An object of the present invention is to provide a retardation film having a negative optically anisotropic layer made of a liquid crystalline compound, which is advantageous in terms of thinning, weight reduction, productivity and production cost, and a method for producing the film. There is to do.

The object of the present invention has been achieved by the following means.
[1] A retardation film having at least two optically anisotropic layers containing a liquid crystalline compound fixed in an aligned state, wherein at least one of the two optically anisotropic layers is negative. A retardation film comprising: an optically anisotropic layer having no alignment film between the two adjacent optically anisotropic layers.
[2] The retardation film according to [1], wherein the negative optically anisotropic layer contains a compound represented by the following general formula (1) or (PX).
(1) {(Hb-L ^1- ) _m Cy ¹ -L ^2- } _n Cy ²
(In the formula, Hb is an aliphatic group having 6 to 40 carbon atoms or an aliphatic substituted oligosiloxanoxy group having 6 to 40 carbon atoms, and L ¹ is a single bond or a divalent linking group. , L ² is a divalent group selected from the group consisting of a single bond, an alkylene group, an alkenylene group, an alkynylene group, —O—, —S—, —CO—, —NR ³ —, —SO ₂ —, and combinations thereof. R ³ is a linking group, R ³ is a hydrogen atom or an alkyl group having 1 to 20 carbon atoms, Cy ¹ is an (m + 1) -valent cyclic group, Cy ² is an n-valent cyclic group, and n is (It is an integer of 2 to 12. In addition, the compound represented by the general formula (1) has at least one polymerizable group.)
(PX)-(VA1) _x- (HyD) _y- (VAc) _z-
(In the formula, VAl is a vinyl alcohol repeating unit, HyD is a repeating unit having a hydrocarbon group having 9 or less carbon atoms, VAc is a vinyl acetate repeating unit, and x is 20 to 95 mol%. y is 2 to 80 mol%, and z is 0 to 30 mol%.)

[3] After forming the negative optical anisotropic layer containing the liquid crystalline compound fixed in the alignment state, the surface is rubbed, and a composition containing the liquid crystalline compound is applied to align the liquid crystalline compound. The retardation film manufacturing method according to [1], wherein the second optically anisotropic layer is formed by fixing to the orientation state.
[4] including a step of applying a composition containing a liquid crystalline compound and a compound represented by the following general formula (1) or (PX) to form the negative optically anisotropic layer [3] The manufacturing method as described in.
(1) {(Hb-L ^1- ) _m Cy ¹ -L ^2- } _n Cy ²
(In the formula, Hb is an aliphatic group having 6 to 40 carbon atoms or an aliphatic substituted oligosiloxanoxy group having 6 to 40 carbon atoms, and L ¹ is a single bond or a divalent linking group. , L ² is a divalent group selected from the group consisting of a single bond, an alkylene group, an alkenylene group, an alkynylene group, —O—, —S—, —CO—, —NR ³ —, —SO ₂ —, and combinations thereof. R ³ is a linking group, R ³ is a hydrogen atom or an alkyl group having 1 to 20 carbon atoms, Cy ¹ is an (m + 1) -valent cyclic group, Cy ² is an n-valent cyclic group, and n is (It is an integer of 2 to 12. In addition, the compound represented by the general formula (1) has at least one polymerizable group.)
(PX)-(VA1) _x- (HyD) _y- (VAc) _z-
(In the formula, VAl is a vinyl alcohol repeating unit, HyD is a repeating unit having a hydrocarbon group having 9 or less carbon atoms, VAc is a vinyl acetate repeating unit, and x is 20 to 95 mol%. y is 2 to 80 mol%, and z is 0 to 30 mol%.)
In this specification, “substantially no alignment film” means that a film formed only for functioning as an alignment film is not included. Even if the surface of the lower layer (for example, a negative optical anisotropic layer) contributes to the alignment of the liquid crystalline compound of the upper layer, the lower layer is used as an alignment film. As long as it is not formed for use only.

  The present invention contributes to improving the productivity and reducing the production cost of a retardation film having a negative optically anisotropic layer made of a liquid crystalline compound. In addition, the present invention contributes to reducing the thickness, reducing the weight, improving the productivity, and reducing the production cost of the retardation film having a negative optically anisotropic layer made of a liquid crystalline compound.

BEST MODE FOR CARRYING OUT THE INVENTION

  The retardation film of the present invention has at least one negative optically anisotropic layer and an optically anisotropic layer adjacent thereto. The negative optically anisotropic layer and the optically anisotropic layer adjacent thereto are formed from a composition containing a liquid crystal compound, and liquid crystal molecules are fixed in an aligned state in the layer. There is substantially no alignment film between the negative optically anisotropic layer and the optically anisotropic layer adjacent thereto. For example, the negative optically anisotropic layer is subjected to a treatment that can also function as an alignment film, and a composition containing another liquid crystalline compound is applied directly to the negative optically anisotropic layer. Thus, a liquid crystal layer in which liquid crystals are aligned in a desired direction can be formed adjacent to the surface. As a result, the process of applying the alignment film can be omitted, and a process that is simple and excellent in productivity can be realized.

  In order to make the negative optical anisotropic layer function as an alignment film of the optical anisotropic layer formed adjacent to the negative optical anisotropic layer, the composition used when forming the negative optical anisotropic layer A certain additive (hereinafter referred to as an alignment film precursor) is added. The alignment film precursor is a layer formed by applying the composition and then aligning the liquid crystalline compound contained in the composition and fixing the alignment state to form an optically anisotropic layer. To the air interface side, and a layer in which the alignment film precursor is unevenly distributed is formed on the surface. By rubbing the surface of the layer, the function as an alignment film of another optically anisotropic layer laminated thereon can be expressed.

The alignment film precursor will be described below. Any alignment film precursor may be used as long as it causes phase separation from the liquid crystalline compound, is unevenly distributed on the surface, and functions as an alignment film by rubbing. The compounds that exhibit such a function can be roughly classified into low molecular compounds and polymers. Here, the low molecular weight compound means a compound that is not a polymer polymer having a repeating unit.
<Low molecular compound alignment film precursor>
The low molecular compound type alignment film precursor is preferably represented by the following general formula (1).
(1) {(Hb-L ^1- ) _m Cy ¹ -L ^2- } _n Cy ²
In Formula (1), Hb is an aliphatic group having 6 to 40 carbon atoms or an aliphatic substituted oligosiloxanoxy group having 6 to 40 carbon atoms. Hb is preferably an aliphatic group having 6 to 40 carbon atoms, and is a fluorine-substituted aliphatic group having 6 to 40 carbon atoms or a branched aliphatic group having 6 to 40 carbon atoms. More preferably, it is a fluorine-substituted alkyl group having 6 to 40 carbon atoms or a branched alkyl group having 6 to 40 carbon atoms.

  The aliphatic group is preferably a chain aliphatic group rather than a cyclic aliphatic group. The chain aliphatic group may have a branch. The number of carbon atoms in the aliphatic group is preferably 7 to 35, more preferably 8 to 30, further preferably 9 to 25, and most preferably 10 to 20. Aliphatic groups include alkyl groups, substituted alkyl groups, alkenyl groups, substituted alkenyl groups, alkynyl groups and substituted alkynyl groups. An alkyl group, a substituted alkyl group, an alkenyl group and a substituted alkenyl group are preferred, and an alkyl group and a substituted alkyl group are more preferred. Examples of the substituent of the aliphatic group include a halogen atom, hydroxyl, cyano, nitro, alkoxy group, substituted alkoxy group (eg, oligoalkoxy group), alkenyloxy group (eg, vinyloxy), acyl group (eg, acryloyl). Methacryloyl), acyloxy groups (eg, acryloyloxy, benzoyloxy), sulfamoyl, aliphatic substituted sulfamoyl groups and epoxy groups (eg, epoxyethyl). As the substituent, a halogen atom is preferable, and a fluorine atom is more preferable. In the fluorine-substituted aliphatic group, the ratio of the fluorine atom replacing the hydrogen atom of the aliphatic group is preferably 50 to 100%, more preferably 60 to 100%, and 70 to 100%. More preferably, it is more preferably 80 to 100%, and most preferably 85 to 100%.

The number of carbon atoms of the aliphatic substituted oligosiloxanoxy group is preferably 7 to 35, more preferably 8 to 30, further preferably 9 to 25, and 10 to 20. Is most preferred. The aliphatic substituted oligosiloxanoxy group is represented by the following formula.
R ¹ − {Si (R ² ) ₂ —O} _q −
In the formula, R ¹ is a hydrogen atom, hydroxyl or an aliphatic group, R ² is a hydrogen atom, an aliphatic group or an alkoxy group, and q is an integer of 1 to 12. The aliphatic group has the same meaning as described above. The aliphatic group in the aliphatic substituted siloxanoxy group is preferably a chain aliphatic group rather than a cyclic aliphatic group. The chain aliphatic group may have a branch. The number of carbon atoms in the aliphatic group is preferably 1 to 12, more preferably 1 to 8, still more preferably 1 to 6, and still more preferably 1 to 4.

In the formula (1), preferred specific examples of Hb are shown below.
Hb1: n-C ₁₆ H ₃₃ −
_{Hb2: n-C 20 H 41} -
_{Hb3: n-C 6 H 13} -CH (n-C 4 H 9) -CH 2 -CH 2 -
_{Hb4: n-C 12 H 25} -
_{Hb5: n-C 18 H 37} -
_{Hb6: n-C 14 H 29} -
_{Hb7: n-C 15 H 31} -
_{Hb8: n-C 10 H 21} -
_{Hb9: n-C 10 H 21} -CH (n-C 4 H 9) -CH 2 -CH 2 -
_{Hb10: n-C 8 F 17} -

_{Hb11: n-C 8 H 17} -
_{Hb12: CH (CH 3) 2} - {C 3 H 6 -CH (CH 3)} 3 -C 2 H 4 -
_{Hb13: CH (CH 3) 2} - {C 3 H 6 -CH (CH 3)} 2 -C 3 H 6 -C (CH 3) = CH-CH 2 -
_{Hb14: n-C 8 H 17} -CH (n-C 6 H 13) -CH 2 -CH 2 -
_{Hb15: n-C 6 H 13} -CH (C 2 H 5) -CH 2 -CH 2 -
_{Hb16: n-C 8 F 17} -CH (n-C 4 F 9) -CH 2 -
_{Hb17: n-C 8 F 17} -CF (n-C 6 F 13) -CF 2 -CF 2 -
_{Hb18: n-C 3 F 7} -CF (CF 3) -CF 2 -
_{Hb19: (CH 3) 3 Si-} {O-Si (CH 3) 2} 6 -O-
_{Hb20: (C 3 H 7 O} ) Si (C 16 F 33) (C 2 H 4 -SO 2 -NH-C 8 F 17) -O-

In the formula (1), L ¹ is a single bond or a divalent linking group. The divalent linking group is preferably selected from the group consisting of an alkylene group, a fluorine-substituted alkylene group, —O—, —S—, —CO—, —NR ³ —, —SO ₂ —, and combinations thereof. . R ³ is a hydrogen atom or an alkyl group having 1 to 20 carbon atoms. L ¹ is more preferably a divalent linking group selected from the group consisting of an alkylene group, —O—, —S—, —CO—, —NR ³ —, —SO ₂ —, and combinations thereof. . R ³ is preferably a hydrogen atom or an alkyl group having 1 to 20 carbon atoms, more preferably a hydrogen atom or an alkyl group having 1 to 15 carbon atoms, and the hydrogen atom or the number of carbon atoms is Most preferably, it is a 1-12 alkyl group. The alkylene group or the fluorine-substituted alkylene group preferably has 1 to 40 carbon atoms, more preferably 1 to 30, more preferably 1 to 20, and more preferably 1 to 15. Furthermore, it is preferable and it is most preferable that it is 1-12.

Hereinafter, specific preferred examples of L ^1. In the following, the left side is bonded to Hb, and the right side is bonded to Cy ¹ .
L1-0: Single bond L1-1: -O-
L1-2: —O—CO—
L1-3: —O—C ₄ H ₈ —CO—
L1-4: —O—C ₂ H ₄ —O—C ₂ H ₄ —O—
L1-5: -S-
_{L1-6: -N (n-C 12} H 25) -
L1-7: —O—CH ₂ CH ₂ —N (n—C ₃ H ₇ ) —SO ₂ —
L1-8: —CF (CF ₃ ) — {O—CF ₂ —CF (CF ₃ )} ₃ —O—

  In Formula (1), m is an integer of 1-5. m is preferably an integer of 1 to 3, and more preferably 1 or 2.

In Formula (1), Cy ¹ is an (m + 1) -valent cyclic group. Cy ¹ is preferably a (m + 1) -valent aromatic group or a (m + 1) -valent heterocyclic group, and more preferably a (m + 1) -valent aromatic group. The (m + 1) -valent aromatic group means an arylene group or a substituted arylene group. Examples of arylene groups include phenylene, indenylene, naphthylene, fluorenylene, phenanthrenylene, anthracenylene and pyrenylene. Phenylene and naphthylene are preferred. Examples of the substituent of the substituted arylene group include aliphatic group, aromatic group, heterocyclic group, halogen atom, alkoxy group (eg, methoxy, ethoxy, methoxyethoxy), aryloxy group (eg, phenoxy), arylazo group (Eg, phenylazo), alkylthio group (eg, methylthio, ethylthio, propylthio), alkylamino group (eg, methylamino, propylamino), acyl group (eg, acetyl, propanoyl, octanoyl, benzoyl), acyloxy group (eg, Acetoxy, pivaloyloxy, benzoyloxy), hydroxyl, mercapto, amino, carboxyl, sulfo, carbamoyl, sulfamoyl and ureido.

  The (m + 1) -valent heterocyclic group preferably has a 5-membered, 6-membered or 7-membered heterocyclic ring. A 5-membered ring or a 6-membered ring is more preferable, and a 6-membered ring is most preferable. As the hetero atom constituting the heterocyclic ring, a nitrogen atom, an oxygen atom and a sulfur atom are preferable. The heterocycle is preferably an aromatic heterocycle. Examples of heterocyclic rings include furan ring, thiophene ring, pyrrole ring, pyrrolidine ring, oxazole ring, isoxazole ring, thiazole ring, isothiazole ring, imidazole ring, imidazoline ring, imidazolidine ring, pyrazole ring, pyrazoline ring, pyrazolidine Rings, triazole rings, furazane rings, tetrazole rings, pyran rings, pyridine rings, piperidine rings, oxazine rings, morpholine rings, thiazine rings, pyridazine rings, pyrimidine rings, pyrazine rings, piperazine rings and triazine rings are included.

  Another heterocyclic ring, an aliphatic ring or an aromatic ring may be condensed with the above heterocyclic ring. Examples of the condensed heterocyclic ring include benzofuran ring, isobenzofuran ring, benzothiophene ring, indole ring, indoline ring, isoindole ring, benzoxazole ring, benzothiazole ring, indazole ring, benzimidazole ring, chromene ring, chroman ring, Isochroman ring, quinoline ring, isoquinoline ring, cinnoline ring, phthalazine ring, quinazoline ring, quinoxaline ring, dibenzofuran ring, carbazole ring, xanthene ring, acridine ring, phenanthridine ring, phenanthroline ring, phenazine ring, phenoxazine ring, thianthrene ring , An indolizine ring, a quinolidine ring, a quinuclidine ring, a naphthyridine ring, a purine ring and a pteridine ring.

The (m + 1) -valent heterocyclic group may have a substituent. The example of a substituent is the same as the example of the substituent of a substituted arylene group. The (m + 1) -valent heterocyclic group may be a hetero atom (for example, a nitrogen atom of a piperidine ring) and may be bonded to L ² or a cyclic group Cy ^{2 at the} center of the molecule. In addition, the bonded hetero atom may form an onium salt (eg, oxonium salt, sulfonium salt, ammonium salt).

^{Hereinafter, (Hb-L 1 -)} - Specific examples of the group represented by _m Cy ¹ -L ^2.

In the formula (1), L ² is a group consisting of a single bond, an alkylene group, an alkenylene group, an alkynylene group, —O—, —S—, —CO—, —NR ⁴ —, —SO ₂ —, and combinations thereof. It is a divalent linking group selected from. R ⁴ is a hydrogen atom or an alkyl group having 1 to 30 carbon atoms. L ² is preferably a divalent linking group selected from the group consisting of —O—, —S—, —CO—, —NR ⁴ —, —SO ₂ —, and combinations thereof. R ⁴ is preferably a hydrogen atom or an alkyl group having 1 to 20 carbon atoms, more preferably a hydrogen atom or an alkyl group having 1 to 15 carbon atoms, and the hydrogen atom or the number of carbon atoms is Most preferably, it is a 1-12 alkyl group. The alkylene group preferably has 1 to 40 carbon atoms, more preferably 1 to 30, more preferably 1 to 20, still more preferably 1 to 15, and still more preferably 1 to 1. Most preferably, it is ~ 12. The number of carbon atoms of the alkenylene group or alkynylene group is preferably 2 to 40, more preferably 2 to 30, further preferably 2 to 20, and further preferably 2 to 15. Preferably, it is 2-12.

A specific example of L ² is shown below. In the following, the left side is bonded to Cy ¹ and the right side is bonded to Cy ² .
L2-0: Single bond L2-1: -S-
L2-2: —NH—
L2-3: —NH—SO ₂ —NH—
L2-4: —NH—CO—NH—
L2-5: —SO ₂ —
L2-6: —O—NH—
L2-7: -C≡C-
L2-8: —CH═CH—S—
L2-9: —CH ₂ —O—
L2-10: —N (CH ₃ ) —
L2-11: -CO-O-
L2-12: —CO—NH—

  In Formula (1), n is an integer of 2-12. n is preferably an integer of 2 to 9, more preferably an integer of 2 to 6, further preferably 2, 3 or 4, and most preferably 3 or 4.

In formula (1), Cy ² is an n-valent cyclic group. Cy ² is preferably an n-valent aromatic group or an n-valent heterocyclic group. Examples of the aromatic ring of the aromatic group include a benzene ring, an indene ring, a naphthalene ring, a fluorene ring, a phenanthrene ring, an anthracene ring and a pyrene ring. A benzene ring and a naphthalene ring are preferable, and a benzene ring is particularly preferable. The aromatic group may have a substituent. Examples of substituents include aliphatic groups, aromatic groups, heterocyclic groups, halogen atoms, alkoxy groups (eg, methoxy, ethoxy, methoxyethoxy), aryloxy groups (eg, phenoxy), arylazo groups (eg, phenylazo ), Alkylthio groups (eg, methylthio, ethylthio, propylthio), alkylamino groups (eg, methylamino, propylamino), arylamino groups (eg, phenylamino), acyl groups (eg, acetyl, propanoyl, octanoyl, benzoyl) , Acyloxy groups (eg, acetoxy, pivaloyloxy, benzoyloxy), hydroxyl, mercapto, amino, carboxyl, sulfo, carbamoyl, sulfamoyl and ureido.

The heterocyclic group preferably has a 5-membered, 6-membered or 7-membered heterocyclic ring. A 5-membered ring or a 6-membered ring is more preferable, and a 6-membered ring is most preferable. As the hetero atom constituting the heterocyclic ring, a nitrogen atom, an oxygen atom and a sulfur atom are preferable. The heterocycle is preferably an aromatic heterocycle. The aromatic heterocycle is generally an unsaturated heterocycle. An unsaturated heterocyclic ring having the most double bond is more preferable. Examples of heterocyclic rings include furan ring, thiophene ring, pyrrole ring, pyrrolidine ring, oxazole ring, isoxazole ring, thiazole ring, isothiazole ring, imidazole ring, imidazoline ring, imidazolidine ring, pyrazole ring, pyrazoline ring, pyrazolidine Rings, triazole rings, furazane rings, tetrazole rings, pyran rings, thiyne rings, pyridine rings, piperidine rings, oxazine rings, morpholine rings, thiazine rings, pyridazine rings, pyrimidine rings, pyrazine rings, piperazine rings and triazine rings are included. A triazine ring is preferred, and a 1,3,5-triazine ring is particularly preferred. The heterocycle may be condensed with another heterocycle, aliphatic ring or aromatic ring. However, monocyclic heterocycles are preferred.
A specific example of Cy ² is shown below.

The alignment film precursor is a compound in which the hydrophobic group (Hb), the linking group (L ¹ ) and the unit (Cy ¹ -L ^2- ) _n Cy ² having the excluded volume effect described above are combined. There are no particular restrictions on these combinations.

  The alignment film precursor used in the present invention preferably has 3 or more aromatic rings (counts constituent components when condensed), more preferably 4 or more. A plurality of liquid crystal alignment accelerators may be used in combination. The molecular weight of the low molecular alignment film precursor is preferably 2500 or less, more preferably 2000 or less, and particularly preferably 1500 or less from the viewpoint of the phase separation rate.

The compound represented by the formula (1) has a polymerizable group in the molecule. The number of polymerizable groups is preferably 1 to 10, more preferably 2 to 6. The polymerizable group may be bonded to any position of Hb, L ¹ , Cy ¹ , L ² or Cy ^{2 in} the general formula (1), but is preferably bonded to Hb. As the polymerizable group, a polymerizable ethylenically unsaturated group or a ring-opening polymerizable group is preferable. Examples of the polymerizable ethylenically unsaturated group include the following (M-1) to (M-6).

  In the formula, R represents a hydrogen atom or a substituent, but is preferably a hydrogen atom or an alkyl group, particularly preferably a hydrogen atom or a methyl group. Among these, (M-1) or (M-2) is preferable, and (M-1) is most preferable. A cyclic ether group is preferable as the ring-opening polymerizable group, and an epoxy group or an oxetanyl group is more preferable, and an epoxy group is most preferable.

  Although the example of the low molecular type alignment film precursor of this invention is given to the following, this invention is not limited to these.

The compound of the present invention can be synthesized with reference to, for example, the method described in JP-A-2002-20363. A specific synthesis example of the alignment film precursor represented by the general formula (I) is shown below.
(Synthesis Example) Synthesis of Exemplified Compound (I)

(Ia, 22 mmol) was dissolved in methyl ethyl ketone (50 ml) and cooled with ice water. A solution of (Ib, 43 mmol) in methyl ethyl ketone (60 ml) and triethylamine (44 mmol) was added dropwise so as to maintain a temperature of 30 ° C. or lower, and then the reaction solution was refluxed for 3 hours. After cooling to room temperature, ethyl acetate (200 ml) was added and washed with water. The organic layer was concentrated and purified by silica gel column chromatography (eluent: ethyl acetate / hexane = 1/7, volume ratio) to obtain (Ic) in a yield of 62%.
A mixture of (Ic, 1 mmol) and (1-d, 1 mmol) was dissolved in methyl ethyl ketone (20 ml), triethylamine (1.5 mmol) was added thereto, and the mixture was refluxed for 4 hours. Thereafter, ethyl acetate (100 ml) was added, washed with water, concentrated, and purified by silica gel column chromatography (eluent: ethyl acetate / hexane = 1/1, volume ratio) to obtain (Ie) at a yield of 60%. Obtained at a rate.
(1-e, 0.3 mmol) was dissolved in N, N-dimethylacetamide (5 ml), and acrylic acid chloride (0.9 mmol) was added thereto, followed by stirring at room temperature overnight. Ethyl acetate (40 ml) was added, washed with water, concentrated, and purified by silica gel chromatography (eluent: ethyl acetate / hexane = 1/2, volume ratio) to obtain Exemplified Compound (I) in a yield of 36%. It was.

<Polymer type alignment film precursor>
Next, the polymer type alignment film precursor will be described. The polymer may be any polymer that can be dissolved in the liquid crystal layer coating solution. An example of a polymer is shown below.
Polypropylene oxide polytetramethylene oxide poly-ε-caprolactone poly-ε-caprolactone diol poly-ε-caprolactone triol polyvinyl acetate polymelamine poly (ethylene adipate)
Poly (1,4-butylene adipate)
Poly (1,4-butylene glutarate)
Poly (1,2-butylene glycol)
Poly (1,4-butylene succinate)
Poly (1,4-butylene terephthalate)
polyethylene terephthalate)
Poly (2-methyl-1,3-propylene adipate)
Poly (2-methyl-1,3-propylene glutarate)
Poly (neopentyl glycol adipate)
Poly (neopentyl glycol sebacate)
Poly (1,3-propylene adipate)
Poly (1,3-propylene glutarate)
Polyvinyl butyral polyvinyl formal polyvinyl acetal polyvinyl propanal polyvinyl hexanal polyvinyl pyrrolidone polyacrylic acid ester polymethacrylic acid ester poly (3-hydroxybutyric acid)

The polymer used as the alignment film precursor is preferably a modified polyvinyl alcohol having a hydrocarbon group having 9 or less carbon atoms. A preferable modified polyvinyl alcohol is represented by the following formula (PX).
(PX)-(VA1) _x- (HyD) _y- (VAc) _z-
In the formula, VAl is a vinyl alcohol repeating unit, HyD is a repeating unit having a hydrocarbon group having 9 or less carbon atoms, VAc is a vinyl acetate repeating unit, and x is 20 to 95 mol% (preferably Is 25 to 90 mol%), y is 2 to 80 mol% (preferably 3 to 70 mol%), and z is 0 to 30 mol% (preferably 2 to 20 mol%). The hydrocarbon group is an aliphatic group, an aromatic group, or a combination thereof. The aliphatic group may be cyclic, branched or linear. The aliphatic group is preferably an alkyl group (which may be a cycloalkyl group) or an alkenyl group (which may be a cycloalkenyl group). The hydrocarbon group may have a substituent. The hydrocarbon group has 1 to 9 carbon atoms, and preferably 1 to 8 carbon atoms. Preferred repeating units (HyD) having a hydrocarbon group having 9 or less carbon atoms are represented by the following formulas (HyD-I) and (HyD-II).

In the formula, L ¹¹ is a divalent linking group selected from —O—, —CO—, —SO ₂ —, —NH—, an alkylene group, an arylene group, and combinations thereof, and L ¹² is a single bond Or a divalent linking group selected from —O—, —CO—, —SO ₂ —, —NH—, an alkylene group, an arylene group, and combinations thereof, and R ¹¹ and R ¹² are each the number of carbon atoms Is a hydrocarbon group of 9 or less. Examples of the divalent linking group formed by the above combination are shown below.
L1: -O-CO-
L2: -O-CO-alkylene group -O-
L3: -O-CO-alkylene group -CO-NH-
L4: -O-CO- alkylene group -NH-SO ₂ - arylene group -O-
L5: -Arylene group -NH-CO-
L6: -Arylene group -CO-O-
L7: -Arylene group -CO-NH-
L8: -Arylene group -O-
L9: -O-CO-NH-arylene group -NH-CO-

  Specific examples of HyD are shown below.

  The polymerization degree of the polymer used for the alignment film precursor is preferably 200 to 5,000, and more preferably 300 to 3,000. The molecular weight of the polymer is preferably 9,000 to 200,000, and more preferably 13,000 to 130,000. Two or more kinds of polymers may be used in combination.

Specific examples of preferred polymer type alignment film precursors are shown below, but the present invention is not limited thereto.
_{PX-1 :-( VAl) 21 -} (HyD-13) 77 - (VAc) 2 -
_{PX-2 :-( VAl) 14 -} (HyD-13) 84 - (VAc) 2 -
_{PX-3 :-( VAl) 21 -} (HyD-16) 77 - (VAc) 2 -
_{PX-4 :-( VAl) 34 -} (HyD-15) 64 - (VAc) 2 -
_{PX-5 :-( VAl) 29 -} (HyD-12) 69 - (VAc) 2 -
_{PX-6 :-( VAl) 46 -} (HyD-14) 52 - (VAc) 2 -
_{PX-7 :-( VAl) 21 -} (HyD-2) 77 - (VAc) 2 -
_{PX-8 :-( VAl) 17 -} (HyD-8) 85 - (VAc) 2 -
_{PX-9 :-( VAl) 21 -} (HyD-13) 77 - (VAc) 2 -
_{PX-10 :-( VAl) 46 -} (HyD-9) 52 - (VAc) 2 -

  The addition amount of the alignment film precursor is preferably 0.05% by mass to 10% by mass with respect to the liquid crystal compound added to the coating composition. More preferably, it is 0.1 mass%-5 mass%.

  Before applying the upper liquid crystal compound coating solution, it is preferable to perform a rubbing treatment on the surface of the negative optically anisotropic layer. The rubbing treatment can be performed by rubbing the surface of the layer formed of the liquid crystal compound containing the alignment film precursor described above with paper or cloth in a certain direction several times.

The coating composition containing the alignment film precursor may contain a condensing agent. Thereby, the adhesiveness and film strength between the optically anisotropic layer and the adjacent layer can be improved. As the condensing agent, a compound having an isocyanate group or a formyl group at the terminal is preferable. Specific compounds are listed below, but are not limited thereto.
Poly (1,4-butanediol), isophorone diisocyanate terminated poly (1,4-butanediol), tolylene 2,4-diisocyanate terminated poly (ethylene adipate), tolylene 2,4-diisocyanate terminated poly (propylene glycol) ), Tolylene 2,4-diisocyanate terminated,
1,6-diisocyanatohexane 1,8-diisocyanate octane 1,12-diisocyanate dodecaneisophorone diisocyanate glyoxal

  The negative optically anisotropic layer can be formed from a composition containing a liquid crystal compound and optionally other additives such as the alignment film precursor and a polymerization initiator. The liquid crystalline compound is preferably a discotic liquid crystalline molecule or a cholesteric liquid crystalline molecule. A layer exhibiting negative optical anisotropy can be formed by aligning the discotic liquid crystalline molecules substantially horizontally with respect to the substrate. Substantially horizontal means that the average angle (average tilt angle) formed by the optical axis direction of the discotic liquid crystalline molecules and the substrate normal direction is within a range of 0 ± 40 °. The discotic liquid crystal molecule tilt angle may be an oblique orientation other than 0 °, or a hybrid orientation in which the tilt angle gradually changes. Even in the case of oblique orientation or hybrid orientation, the average inclination angle is preferably 0 to 40 °. In addition, a twisting deformation may be added to the orientation state by adding a chiral agent or applying a shear stress.

  Cholesteric liquid crystalline molecules exhibit negative optical anisotropy due to a helical twist arrangement. Therefore, desired optical characteristics can be obtained by arranging the cholesteric liquid crystalline molecules in a spiral and controlling the twist angle and retardation value of the arrangement.

  As rod-like liquid crystalline molecules, azomethines, azoxys, cyanobiphenyls, cyanophenyl esters, benzoic acid esters, cyclohexanecarboxylic acid phenyl esters, cyanophenylcyclohexanes, cyano-substituted phenylpyrimidines, alkoxy-substituted phenylpyrimidines , Phenyldioxanes, tolanes and alkenylcyclohexylbenzonitriles are preferably used. In addition to the above low-molecular liquid crystalline molecules, high-molecular liquid crystalline molecules can also be used. It is more preferable to fix the orientation of the rod-like liquid crystalline molecules by polymerization, and examples of the polymerizable rod-like liquid crystalline molecules include those described in Makromol. Chem. 190, 2255 (1989), Advanced Materials 5, 107 (1993), US Pat. Nos. 4,683,327, 5,622,648 and 5,770,107, World Patents (WO) 95/22586, 95/24455. No. 97/00600, No. 98/23580, No. 98/52905, JP-A-1-272551, No. 6-16616, No. 7-110469, No. 11-80081, and Japanese Patent Application No. 2001-2001. The compounds described in No. 64627 can be used. More preferably, it is a compound represented by the following general formula (2).

(2) Q ³¹ -L ³¹ -Cy ³¹ -L ^32- (Cy ³² -L ³³ ) _k -Cy ³³ -L ³⁴ -Q ³²
In the formula, Q ³¹ and Q ³² are each independently a polymerizable group, L ³¹ and L ³⁴ are each independently a divalent linking group, and L ³² and L ³³ are each independently a single bond or a divalent group. It is a linking group, Cy ³¹ , Cy ³² and Cy ³³ are divalent cyclic groups, and k is 0, 1 or 2. Examples of the polymerizable group include those described in the description of the general formula (1).

L ³¹ and L ³⁴ are each independently a divalent linking group. L ³¹ and L ³⁴ are each independently selected from the group consisting of —O—, —S—, —CO—, —NR ⁵ —, a divalent chain group, a divalent cyclic group, and combinations thereof. A valent linking group is preferred. R ⁵ is an alkyl group having 1 to 7 carbon atoms or a hydrogen atom.
Examples of divalent linking groups composed of these combinations are shown below. In the following, the left side is the Q ³¹ or Q ^32, the right side is attached to Cy ³¹ or Cy ^33.
L3-1: -CO-O-divalent chain group -O-
L3-2: —CO—O—divalent chain group —O—CO—
L3-3: -CO-O-divalent chain group -O-CO-O-
L3-4: -CO-O-divalent chain group -O-divalent cyclic group-
L3-5: -CO-O-divalent chain group -O-divalent cyclic group -CO-O-
L3-6: -CO-O-divalent chain group -O-divalent cyclic group -O-CO-
L3-7: -CO-O-divalent chain group-O-divalent cyclic group-divalent chain group-
L3-8: -CO-O-divalent chain group-O-divalent cyclic group-divalent chain group-CO-O-
L3-9: -CO-O-divalent chain group-O-divalent cyclic group-divalent chain group-O-CO-
L3-10: —CO—O—divalent chain group—O—CO—divalent cyclic group—
L3-11: -CO-O-divalent chain group -O-CO-divalent cyclic group -CO-O-
L3-12: -CO-O-divalent chain group -O-CO-divalent cyclic group -O-CO-
L3-13: —CO—O—Divalent Chain Group—O—CO—Divalent Cyclic Group—Divalent Chain Group—
L3-14: -CO-O-divalent chain group-O-CO-divalent cyclic group-divalent chain group-CO-O-
L3-15: -CO-O-divalent chain group-O-CO-divalent cyclic group-divalent chain group-O-CO-
L3-16: —CO—O—divalent chain group—O—CO—O—divalent cyclic group—
L3-17: -CO-O-divalent chain group -O-CO-O-divalent cyclic group -CO-O-
L3-18: -CO-O-divalent chain group -O-CO-O-divalent cyclic group -O-CO-
L3-19: —CO—O—divalent chain group—O—CO—O—divalent cyclic group—divalent chain group—
L3-20: -CO-O-divalent chain group-O-CO-O-divalent cyclic group-divalent chain group-CO-O-
L3-21: -CO-O-divalent chain group-O-CO-O-divalent cyclic group-divalent chain group-O-CO-

The divalent chain group means an alkylene group, a substituted alkylene group, an alkenylene group, a substituted alkenylene group, an alkynylene group, or a substituted alkynylene group. An alkylene group, a substituted alkylene group, an alkenylene group and a substituted alkenylene group are preferred, and an alkylene group and an alkenylene group are more preferred.
The alkylene group may have a branch. The alkylene group preferably has 1 to 12 carbon atoms, more preferably 2 to 10 carbon atoms, and most preferably 2 to 8 carbon atoms.
The alkylene part of the substituted alkylene group is the same as the above alkylene group. Examples of the substituent include a halogen atom.
The alkenylene group may have a branch. The alkenylene group preferably has 2 to 12 carbon atoms, more preferably 2 to 10 carbon atoms, and most preferably 2 to 8 carbon atoms.
The alkenylene part of the substituted alkenylene group is the same as the above alkenylene group. Examples of the substituent include a halogen atom.
The alkynylene group may have a branch. The alkynylene group preferably has 2 to 12 carbon atoms, more preferably 2 to 10 carbon atoms, and most preferably 2 to 8 carbon atoms.
The alkynylene part of the substituted alkynylene group is the same as the above alkynylene group. Examples of the substituent include a halogen atom.
Specific examples of the divalent chain group include ethylene, trimethylene, tetramethylene, 1-methyl-1,4-butylene, pentamethylene, hexamethylene, octamethylene, 2-butenylene, 2-butynylene and the like.

The definition and examples of the divalent cyclic group are the same as those of Cy ³¹ , Cy ³² and Cy ³³ described later.
R ⁵ is preferably an alkyl group having 1 to 4 carbon atoms or a hydrogen atom, more preferably a methyl group, an ethyl group or a hydrogen atom, and most preferably a hydrogen atom.

L ^{32 and} L ³³ are each independently a single bond or a divalent linking group. L ³² and L ³³ are each independently selected from the group consisting of —O—, —S—, —CO—, —NR ³² —, a divalent chain group, a divalent cyclic group, and combinations thereof. A valent linking group or a single bond is preferred. R ³² is an alkyl group having 1 to 7 carbon atoms or a hydrogen atom, preferably an alkyl group having 1 to 4 carbon atoms or a hydrogen atom, and preferably a methyl group, an ethyl group or a hydrogen atom. More preferably, it is a hydrogen atom. The divalent chain group and the divalent cyclic group have the same definitions as L ³¹ and L ³⁴ .

In the formula (2), k is 0, 1 or 2. When k is 2, two L ³³ may be the same or different, and two Cy ³² may be the same or different. k is preferably 1 or 2, and more preferably 1.

In formula (2), Cy ³¹ , Cy ³² and Cy ³³ are each independently a divalent cyclic group. The ring contained in the cyclic group is preferably a 5-membered ring, a 6-membered ring, or a 7-membered ring, more preferably a 5-membered ring or a 6-membered ring, and most preferably a 6-membered ring. The ring contained in the cyclic group may be a condensed ring. However, it is more preferably a monocycle than a condensed ring.
The ring contained in the cyclic group may be any of an aromatic ring, an aliphatic ring, and a heterocyclic ring. Examples of the aromatic ring include a benzene ring and a naphthalene ring. Examples of the aliphatic ring include a cyclohexane ring. Examples of the heterocyclic ring include a pyridine ring and a pyrimidine ring. As the cyclic group having a benzene ring, 1,4-phenylene is preferable. As the cyclic group having a naphthalene ring, naphthalene-1,5-diyl and naphthalene-2,6-diyl are preferable. The cyclic group having a cyclohexane ring is preferably 1,4-cyclohexylene. As the cyclic group having a pyridine ring, pyridine-2,5-diyl is preferable. The cyclic group having a pyrimidine ring is preferably pyrimidine-2,5-diyl.
The cyclic group may have a substituent. Examples of the substituent include a halogen atom, a cyano group, a nitro group, an alkyl group having 1 to 5 carbon atoms, a halogen-substituted alkyl group having 1 to 5 carbon atoms, and an alkoxy group having 1 to 5 carbon atoms. , An alkylthio group having 1 to 5 carbon atoms, an acyloxy group having 2 to 6 carbon atoms, an alkoxycarbonyl group having 2 to 6 carbon atoms, a carbamoyl group, and an alkyl-substituted carbamoyl group having 2 to 6 carbon atoms And an acylamino group having 2 to 6 carbon atoms.

  Examples of the polymerizable liquid crystal compound represented by the formula (2) are shown below. The present invention is not limited to these.

  Next, the discotic liquid crystalline molecules that can be used in the present invention will be further described. The discotic liquid crystalline molecules are preferably aligned substantially horizontally (average tilt angle in the range of 0 to 45 degrees) with respect to the polymer film surface. Discotic liquid crystalline molecules are disclosed in various documents (C. Destrade et al., Mol. Crysr. Liq. Cryst., Vol. 71, page 111 (1981); edited by The Chemical Society of Japan, Quarterly Chemical Review, No. 22, Liquid Crystal Chemistry, Chapter 5, Chapter 10 Section 2 (1994); B. Kohne et al., Angew. Chem. Soc. Chem. Comm., Page 1794 (1985); J. Zhang et al., J Am.Chem.Soc., Vol.116, page 2655 (1994)). The polymerization of discotic liquid crystalline molecules is described in JP-A-8-27284. In order to fix the discotic liquid crystalline molecules by polymerization, it is necessary to bond a polymerizable group as a substituent to the discotic core of the discotic liquid crystalline molecules. However, when the polymerizable group is directly connected to the disc-shaped core, it becomes difficult to maintain the orientation state in the polymerization reaction. Therefore, a linking group is introduced between the discotic core and the polymerizable group. Therefore, the discotic liquid crystalline molecule having a polymerizable group is preferably a compound represented by the following formula (3).

(3) D (-L ⁴ -P) _a
In the formula, D is a discotic core, L ⁴ is a divalent linking group, P is a polymerizable group, and a is an integer of 4 to 12. An example of the disk-shaped core (D) of the formula (3) is shown below. In each of the following examples, LP (or PL) means a combination of a divalent linking group (L ⁴ ) and a polymerizable group (P).

In the formula (3), the divalent linking group (L ⁴ ) is selected from the group consisting of an alkylene group, an alkenylene group, an arylene group, —CO—, —NH—, —O—, —S—, and combinations thereof. It is preferable that it is a bivalent coupling group. The divalent linking group (L ⁴ ) is a combination of at least two divalent groups selected from the group consisting of an alkylene group, an alkenylene group, an arylene group, —CO—, —NH—, —O—, and —S—. More preferably, The divalent linking group (L ⁴ ) is most preferably a group obtained by combining at least two divalent groups selected from the group consisting of an alkylene group, an alkenylene group, an arylene group, —CO— and —O—. . The alkylene group preferably has 1 to 12 carbon atoms. The alkenylene group preferably has 2 to 12 carbon atoms. The number of carbon atoms in the arylene group is preferably 6-10. The alkylene group, alkenylene group and arylene group may have a substituent (eg, alkyl group, halogen atom, cyano, alkoxy group, acyloxy group).

Examples of the divalent linking group (L ⁴ ) are shown below. The left side is bonded to the discotic core (D), and the right side is bonded to the polymerizable group (P). AL represents an alkylene group or an alkenylene group, and AR represents an arylene group.
L4-1: -AL-CO-O-AL-
L4-2: -AL-CO-O-AL-O-
L4-3: -AL-CO-O-AL-O-AL-
L4-4: -AL-CO-O-AL-O-CO-
L4-5: -CO-AR-O-AL-
L4-6: -CO-AR-O-AL-O-
L4-7: -CO-AR-O-AL-O-CO-
L4-8: -CO-NH-AL-
L4-9: -NH-AL-O-
L4-10: —NH—AL—O—CO—

L4-11: -O-AL-
L4-12: -O-AL-O-
L4-13: -O-AL-O-CO-
L4-14: -O-AL-O-CO-NH-AL-
L4-15: -O-AL-S-AL-
L4-16: -O-CO-AL-AR-O-AL-O-CO-
L4-17: -O-CO-AR-O-AL-CO-
L4-18: -O-CO-AR-O-AL-O-CO-
L4-19: -O-CO-AR-O-AL-O-AL-O-CO-
L4-20: -O-CO-AR-O-AL-O-AL-O-AL-O-CO-
L4-21: -S-AL-
L4-22: -S-AL-O-
L4-23: -S-AL-O-CO-
L4-24: -S-AL-S-AL-
L4-25: -S-AR-AL-

  The polymerizable group (P) of the formula (3) is determined according to the type of polymerization reaction. Examples of the polymerizable group (P) are shown below.

The polymerizable group (P) is preferably an unsaturated polymerizable group (P1, P2, P3, P7, P8, P15, P16, P17) or an epoxy group (P6, P18). More preferably, it is most preferably an ethylenically unsaturated polymerizable group (P1, P7, P8, P15, P16, P17). In Formula (IV), a is an integer of 4-12. A specific number is determined according to the type of discotic core (D). Incidentally, a combination of a plurality of L ⁴ and P may be different, but are preferably the same. Two or more kinds of discotic liquid crystalline molecules (for example, a molecule having an asymmetric carbon atom in a divalent linking group and a molecule not having it) may be used in combination.

  The negative optically anisotropic layer is formed by applying a coating solution containing the above-mentioned alignment film precursor, rod-like liquid crystal molecules or discotic liquid crystal molecules and the following polymerizable initiators and other additives onto the alignment film. By doing so, it can be formed. As a solvent used for preparing the coating solution, an organic solvent is preferably used. Examples of organic solvents include amides (eg, N, N-dimethylformamide), sulfoxides (eg, dimethyl sulfoxide), heterocyclic compounds (eg, pyridine), hydrocarbons (eg, benzene, hexane), alkyl halides (eg, , Chloroform, dichloromethane), esters (eg, methyl acetate, butyl acetate), ketones (eg, acetone, methyl ethyl ketone), ethers (eg, tetrahydrofuran, 1,2-dimethoxyethane). Alkyl halides and ketones are preferred. Two or more organic solvents may be used in combination. The coating liquid can be applied by a known method (eg, extrusion coating method, direct gravure coating method, reverse gravure coating method, die coating method).

  The aligned liquid crystal molecules are fixed while maintaining the alignment state. The immobilization is preferably performed by a polymerization reaction of the polymerizable group (P) introduced into the liquid crystal molecule. The polymerization reaction includes a thermal polymerization reaction using a thermal polymerization initiator and a photopolymerization reaction using a photopolymerization initiator. A photopolymerization reaction is preferred. Examples of the photopolymerization initiator include α-carbonyl compounds (described in US Pat. Nos. 2,367,661 and 2,367,670), acyloin ether (described in US Pat. No. 2,448,828), α-hydrocarbon substituted aromatic acyloin. Compound (described in US Pat. No. 2,722,512), polynuclear quinone compound (described in US Pat. Nos. 3,046,127 and 2,951,758), a combination of triarylimidazole dimer and p-aminophenyl ketone (US Pat. No. 3,549,367) Acridine and phenazine compounds (JP-A-60-105667, U.S. Pat. No. 4,239,850) and oxadiazole compounds (U.S. Pat. No. 4,212,970).

The amount of the photopolymerization initiator used is preferably 0.01 to 20% by mass, more preferably 0.5 to 5% by mass, based on the solid content of the coating solution. It is preferable to use ultraviolet rays for light irradiation for polymerization of liquid crystalline molecules. The irradiation energy is preferably ^{20mJ / cm 2 ~50J / cm 2} , further preferably 100 to 800 mJ / cm ^2. In order to accelerate the photopolymerization reaction, light irradiation may be performed under heating conditions. The thickness of the optically anisotropic layer is preferably 0.1 to 10 μm, and more preferably 0.5 to 5 μm.

  In forming the negative optically anisotropic layer, it is preferable to use an alignment film in order to align the liquid crystalline compound. The alignment film may be an organic compound (for example, ω-triconic acid) formed by rubbing treatment of an organic compound (preferably polymer), oblique deposition of an inorganic compound, formation of a layer having a microgroup, or Langmuir-Blodgett method (LB film). , Dioctadecyldimethylammonium chloride, methyl stearylate, etc.). Furthermore, an alignment film in which an alignment function is generated by application of an electric field, application of a magnetic field, or light irradiation is also known. An alignment film formed by a polymer rubbing treatment is particularly preferred. The rubbing process is carried out by rubbing the surface of the polymer layer several times in a certain direction with paper or cloth. The type of polymer used for the alignment film is determined according to the alignment (particularly the average tilt angle) of the liquid crystal compound. In order to align the liquid crystal compound horizontally, a polymer that does not decrease the surface energy of the alignment film (ordinary alignment polymer) is used. Specific types of polymers are described in various documents about liquid crystal cells or optical compensation sheets. Any of the alignment films preferably has a polymerizable group for the purpose of improving the adhesion between the liquid crystal compound and the transparent support. The polymerizable group can be introduced by introducing a repeating unit having a polymerizable group in the side chain or as a substituent of a cyclic group. It is more preferable to use an alignment film that forms a chemical bond with the liquid crystal compound at the interface. Such an alignment film is described in JP-A-9-152509.

  In the case of using an alignment film in which the optical axes of rod-like liquid crystalline molecules are aligned in a direction orthogonal to the rubbing direction (hereinafter referred to as an orthogonal alignment film), JP-A-2002-62427, 2002-268068, etc. The alignment film described in each of the above publications is preferred. The thickness of the alignment film is preferably 0.01 to 5 μm, and more preferably 0.05 to 1 μm.

  Next, the second optically anisotropic layer formed adjacently on the negative optically anisotropic layer will be described. The second optically anisotropic layer is a layer formed from a composition containing a liquid crystal compound. Examples of the liquid crystalline compound used for forming the second optically anisotropic layer include the rod-like liquid crystal and the discotic liquid crystal described in the negative optically anisotropic layer. Since the negative optically anisotropic layer itself has an alignment film function, a second optically anisotropic layer is formed by applying a composition containing a liquid crystalline compound on the surface and orienting the liquid crystalline compound. In doing so, it is not necessary to prepare an alignment film for aligning the liquid crystalline compound. On the other hand, when a composition containing a liquid crystal compound is further applied thereon to form the third optically anisotropic layer, a coating for forming an alignment film is formed on the surface of the second optically anisotropic layer. The composition for forming the third optical anisotropic layer may be applied after the liquid is applied and rubbed, or the surface of the second optical anisotropic layer itself is provided with an alignment film function. The third coating solution for forming an optically anisotropic layer may be applied directly. In the latter case, specifically, a composition in which an alignment film precursor is mixed is used as the second optically anisotropic layer forming composition, and phase separation is performed in the same manner as the negative optically anisotropic layer. A surface layer having an alignment film function is formed on the surface of the second optical anisotropic layer, and the alignment film function is expressed by rubbing. The alignment film used in the former mode, that is, the mode in which a new alignment film is formed on the surface of the second optical anisotropic layer, is the alignment film used when forming the negative optical anisotropic layer. Similar to the example.

  The retardation film of the present invention preferably has a support. The support used in the present invention is preferably transparent, and specifically, the light transmittance is preferably 80% or more. Further, it is preferable to use a polymer film having a small wavelength dispersion as the support, and specifically, the ratio of Re400 / Re700 is preferably less than 1.2. The transparent support also preferably has a small optical anisotropy. Specifically, the in-plane retardation (Re) is preferably 20 nm or less, and more preferably 10 nm or less. The long transparent support has a roll-like or rectangular sheet-like shape. It is preferable to laminate the optically anisotropic layer using a roll-shaped transparent support and then cut it into a required size. Examples of the polymer include cellulose ester, polycarbonate, polysulfone, polyethersulfone, polyacrylate and polymethacrylate. Cellulose esters are preferred, acetyl cellulose is more preferred, and triacetyl cellulose is most preferred. The polymer film is preferably formed by a solvent cast method. The thickness of the transparent support is preferably 20 to 500 μm, and more preferably 50 to 200 μm. In order to improve adhesion between the transparent support and the layer (adhesive layer, vertical alignment film or optically anisotropic layer) provided on the transparent support, surface treatment (eg, glow discharge treatment, corona discharge treatment, ultraviolet ray) is applied to the transparent support. (UV) treatment, flame treatment) may be performed. An adhesive layer (undercoat layer) may be provided on the transparent support. In addition, the retardation film of the present invention is obtained by laminating an optically anisotropic layer on a peeling support, and then bonding the surface opposite to the peeling support to another substrate or the like. You may peel and form a support body.

[Example 1]
A glass plate (5 cm × 10 cm) having a thickness of 0.85 mm was used as a transparent support. On the transparent support, an aqueous solution of modified polyvinyl alcohol modified with methacryloyloxyisocyanate (Polymer No. 1 of JP-A-8-48197) was applied with a bar coater and dried, and the surface was rubbed to form an alignment film. . The thickness of the alignment film was 0.54 μm. On the alignment film, a coating liquid having the following composition is continuously applied using a bar coater, dried and heated (alignment aging), and further irradiated with ultraviolet rays to give a negative optical anisotropy of 1 μm in thickness. Layer A was formed.
──────────────────────────────────
Optically anisotropic layer coating composition ──────────────────────────────────
The following discotic liquid crystalline molecule (1) 13.0 parts by mass The following sensitizer (1) 1.0 part by mass The following photopolymerization initiator (1) 3.0 parts by mass Alignment film precursor Compound, addition amount Is listed in the table below Methyl ethyl ketone 82.0 parts by mass ──────────────────────────────────

The layer is continuously rubbed in various directions (described in Table 1) with respect to the long side direction of the transparent support, and a coating solution having the following composition is continuously applied thereon using a bar coater. Then, drying and heating (orientation aging) were carried out, followed by ultraviolet irradiation to form an optically anisotropic layer B having a thickness of 0.8 μm.
─────────────────────────────────
Optically anisotropic layer coating composition ─────────────────────────────────
14.5 parts by mass of the following rod-like liquid crystalline molecules (1) 1.0 part by mass of the photopolymerization initiator (1) 3.0 parts by mass of the following horizontal alignment accelerator (1) 1.0 part by weight Methyl ethyl ketone 80.5 parts by weight ─────────────────────────────────

  The sample thus prepared was observed with a polarizing microscope, and the orientation of the rod-like liquid crystal was examined. As a result, it was observed that in all samples using the alignment film precursor of the present invention, the rod-like liquid crystals were uniformly aligned in a desired direction. On the other hand, when the alignment film precursor was not used, the rod-like liquid crystal was not aligned. In the conventional process, a step of applying an alignment film after applying a negative optically anisotropic layer is required. However, by using the alignment film precursor of the present invention, another coating liquid for forming an optically anisotropic layer is directly applied on the negative optically anisotropic layer without newly applying an alignment film. Can be uniformly oriented in a desired direction. As a result, the process of laminating an optically anisotropic layer made of a liquid crystalline compound can be performed very simply.

───────────────────────────────────
Specimen Alignment film precursor Amount added Rubbing direction Alignment of rod-shaped liquid crystal ───────────────────────────────────
1 Exemplified compound (1) 2 parts by mass Right hand 30 ° ○
2 Exemplified compound (5) 2 parts by mass Right hand 30 ° ○
3 Exemplified compound (7) 2 parts by mass Right hand 30 ° ○
4 Exemplified compound (PX-9) 0.5 part by mass Right hand 30 ° ○
5 Exemplified compound (1) 2 parts by mass Left hand 30 ° ○
6 Exemplified compound (1) 2 parts by mass Right hand 45 ° ○
7 Exemplified compound (PX-9) 0.5 part by mass Left hand 30 ° ○
8 None 0 Right hand 30 ° ×
9 Comparative Compound (1) 2 parts by mass Right hand 30 ° Δ- ×
───────────────────────────────────
In the table, the rubbing direction represents the direction with respect to the long side direction of the support.
The orientation of the rod-like liquid crystal was evaluated as “◯” when the liquid crystal was uniformly aligned along the rubbing direction, “X” when the alignment was disordered and hardly aligned, and “Δ” as the middle.

[Example 2]
The optically anisotropic layer A having a thickness of 1 μm prepared on a glass plate (5 cm × 10 cm) having a thickness of 0.85 mm in Example 1 was rubbed in the direction of 30 ° to the right hand with respect to the long side direction of the support. A coating solution having the following composition is continuously applied, dried and heated (alignment aging) using a bar coater, and further irradiated with ultraviolet rays to form an optically anisotropic layer B having a thickness of 0.8 μm. did.

────────────────────────────────
Optically anisotropic layer coating composition ────────────────────────────────
14.5 parts by mass of the above-described rod-like liquid crystalline molecule (1) 1.0 part by mass of the above-described sensitizer (1) 3.0 parts by mass of the above-mentioned photopolymerization initiator (1) 2.0 parts by mass Methyl ethyl ketone 80.5 parts by mass ────────────────────────────────

  Next, the optically anisotropic layer B was rubbed in the left hand direction of 30 ° with respect to the longitudinal direction of the support. A coating liquid having the following composition is continuously applied, dried, and heated (orientation aging) using a bar coater, and further irradiated with ultraviolet rays to form an optically anisotropic layer C having a thickness of 1.6 μm. did.

────────────────────────────────
Optically anisotropic layer coating composition ────────────────────────────────
14.5 parts by mass of the above-mentioned rod-like liquid crystalline molecule (1) 1.0 part by mass of the above-mentioned photopolymerization initiator (1) 3.0 parts by mass of the above-mentioned horizontal alignment accelerator (1) 1.0 part by weight Methyl ethyl ketone 80.5 parts by weight ────────────────────────────────

A circularly polarizing plate was produced by bonding the thus produced retardation plate to a 45 ° polarizing plate produced by the method described in Example 2 of JP-A-2002-86554. At this time, the lamination was performed so that the long side direction of the retardation film and the longitudinal direction of the 45 ° polarizing plate coincided.
(Performance evaluation)
The polarizing plate and retardation plate of a commercially available reflective liquid crystal display device (Color Zaurus MI-310, manufactured by Sharp Corporation) were peeled off, and the circularly polarizing plate produced here was attached instead. When the produced reflective liquid crystal display device was visually evaluated, it was found that neutral gray was displayed without any color in any of white display, black display and halftone. Thus, in the conventional process, it is necessary to apply an alignment film between the negative optical anisotropic layer A and the optical anisotropic layer B and between the optical anisotropic layer B and the optical anisotropic layer C. However, by using the technique of the present invention, the process of applying the alignment film can be omitted, and the process can be greatly simplified. In addition, an optical film with good performance can be produced, and the usefulness of the present invention is clear.

Claims (2)

A retardation film having at least two adjacent optically anisotropic layers containing a liquid crystalline compound fixed in an aligned state, wherein at least one of the two optically anisotropic layers is a negative optically different layer. A retardation film having an isotropic layer and having substantially no alignment film between the two adjacent optically anisotropic layers. After forming the negative optical anisotropic layer containing the liquid crystalline compound fixed in the alignment state, the surface is rubbed, and the composition containing the liquid crystalline compound is applied to form the second optical anisotropic layer The manufacturing method of the retardation film of Claim 1 which forms.