JP2000345160A - Liquid crystalline composition and liquid crystal film using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a liquid crystalline composition capable of readily providing a high-quality cholesteric oriented liquid crystal film and useful in optical and optoelectronics fields, and the like, by including specific liquid crystal compounds, or the like, in a specified proportion. SOLUTION: This liquid crystalline composition comprises (A) a compound represented by formula I (R1 and R2 are each H or methyl; X is H, chlorine, bromine, iodine, a 1-4C alkyl, methoxy, cyano or nitro; (a) and (b) are each 2-12), (B) a compound represented by formula II (R3 is H or methyl; (c) is 2-12), (C) a low-molecular compound having an optically active site such as a compound represented by formula III or IV (R4 is H or methyl; (d) and (e) are each 2-12; Y is p,p'-biphenylene, 1,4-cyclohexylene, or the like) in a weight ratio of the components A:B within the range of (99/1) to (50/50) and the content of the component C is within the range of 0.01-60 pts.wt. based on 100 pts.wt. of the total amount of the components A and B. A film of the composition is preferably formed and molecules are subjected to cholestric orientation and immobilized. The resultant film is then preferably irradiated with light and cured to produce the objective liquid crystal film.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a liquid crystal composition and a liquid crystal film using the composition.

[0002]

2. Description of the Related Art Photocurable liquid crystal compounds are produced by active devices such as a light diffusion display using a polymer network liquid crystal, a polymer stabilized ferroelectric liquid crystal display, a photopolymerization-induced liquid crystal phase separation film, or photocuring. Applications to various optical compensation films with improved durability have been reported recently (JLFergason et.al., SID Dig.Tech.
Paper, 16, 68 (1985), PSDrzaic, J. Appl. Phys., 60,
2142 (1986), T. Fujisawa et.al., 1989 Japan Displa
y, 690 (1989)). At present, the demand for photocurable liquid crystal compounds is increasing, and their optical properties and physical properties are attracting attention.Photocurable liquid crystal compounds maintain appropriate fluidity at low temperatures around room temperature, After fixation by light irradiation or the like after orientation, there is a very high possibility that the film can be used in the field of optical compensation films and the like in that a relatively tough film is formed. However, conventional photocurable liquid crystal compounds are difficult to synthesize in a simple and inexpensive manner, which hinders mass production and market expansion of optical compensation films using photocurable liquid crystal compounds. Has become.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to provide two kinds of non-optically active compounds which can be easily synthesized at low cost, and a low molecular weight compound having an optically active site for forming a cholesteric phase in the molecular arrangement. A liquid crystalline mixture composed of
An object of the present invention is to provide a high-quality cholesteric alignment liquid crystal film obtained from a composition containing this mixture.

[0004]

That is, a liquid crystal composition according to the present invention is a compound represented by the following general formula (1):
(I) and a compound (II) represented by the following general formula (2)
And a low molecular weight compound having an optically active site, wherein the weight ratio of compound (I): compound (II) is 99: 1 to 5
0:50, and the content of the low-molecular compound is 100 parts by weight based on the total amount of the compound (I) and the compound (II).
It is in the range of 0.1 to 60 parts by weight.

Embedded image (In the general formulas (1) and (2), R ¹ , R ² and R ³
Each independently represents hydrogen or a methyl group, X represents hydrogen,
It represents one selected from the group consisting of chlorine, bromine, iodine, an alkyl group having 1 to 4 carbon atoms, a methoxy group, a cyano group and a nitro group, and a, b and c each represent an integer of 2 to 12. The compound (III) represented by the following general formula (3) or (4) can be used as the low-molecular compound having an optically active site, which is one component of the liquid crystalline mixture. .

Embedded image (In the general formulas (3) and (4), R ⁴ represents hydrogen or a methyl group, d and e each represent an integer of 2 to 12, and Y is selected from the following (i) to (xxiv). One of the divalent groups shown below.)

Embedded image Here, Z in the above (i) and (ii) represents one selected from the group consisting of hydrogen, chlorine, bromine, an alkyl group having 1 to 4 carbon atoms, a methoxy group, a cyano group and a nitro group.

Embedded image The liquid crystal film according to the present invention can be obtained by forming a film with the above liquid crystalline composition, fixing the molecules in the composition by cholesteric alignment and fixing the film, and then curing the film by light irradiation. .

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail. The liquid crystalline composition of the present invention comprises a compound (I) represented by the general formula (1), a compound (II) represented by the general formula (2), and a low molecular compound having an optically active site. You. As the compound (I), two kinds of compounds included in the general formula (1) can be used in combination. Similarly, as the compound (II), a compound included in the general formula (2) can be used. Can be used as a mixture of two or more. Also, a low molecular compound having an optically active site can be used as a mixture of two or more.
In the general formula (1) representing the compound (I), R ¹ and R ² each represent hydrogen or a methyl group. However, both R ¹ and R ² may be hydrogen because of the wide temperature range in which a liquid crystal phase is exhibited. preferable. X is hydrogen, chlorine, bromine, iodine, carbon number 1
Any of alkyl groups, methoxy groups, cyano groups, and nitro groups may be used, but a chlorine or methyl group is preferable. Further, a and b representing the chain length of the (meth) acryloyloxy group at both ends of the molecular chain of the compound (I) and the alkylene group which is a spacer to the aromatic ring are each independently an arbitrary integer in the range of 2 to 12. Possible but 4
The range is preferably from 10 to 10, and more preferably from 6 to 9. The compound of the general formula (1) in which a = b = 0 has poor stability, is susceptible to hydrolysis, and has high crystallinity of the compound itself. A and b
Is 13 or more, the compound of the general formula (1) has a low isotropic transition temperature (TI). For this reason, these compounds are not preferable because the temperature range in which they exhibit liquid crystallinity is narrow. Compound (I) can be synthesized by any method. For example, compound (I) in which X is a methyl group is obtained by adding 1 equivalent of methylhydroquinone and 2 equivalents of 4-
It can be obtained by an esterification reaction with (m- (meth) acryloyloxyalkoxy) benzoic acid. In the esterification reaction, the above-mentioned benzoic acid is generally activated with an acid chloride, sulfonic anhydride or the like, and the benzoic acid is reacted with methylhydroquinone. Further, a carboxylic acid unit can be directly reacted with methylhydroquinone by using a condensing agent such as DCC (dicyclohexylcarbodiimide). As another method, an esterification reaction between 1 equivalent of methylhydroquinone and 2 equivalents of 4- (m-benzyloxyalkoxy) benzoic acid is first performed, and then the resulting ester is debenzylated by hydrogenation or the like. After that, by the method of acryloylation of the molecular end,
Compound (I) can be synthesized. In carrying out the esterification reaction between methylhydroquinone and 4- (m-benzyloxyalkoxy) benzoic acid, methylhydroquinone is introduced into diacetate, and then reacted with the above benzoic acid in a molten state to obtain an ester directly. It is also possible. Compound (I) in which X in formula (1) is not a methyl group can also be obtained by performing the same reaction as above using a hydroquinone having a corresponding substituent instead of methylhydroquinone.

In the general formula (2) representing the compound (II), R ³ represents hydrogen or a methyl group, but R ³ is preferably hydrogen in view of the wide temperature range showing the liquid crystal phase.
With respect to c indicating the chain length of the alkylene group, the compound (II) having this value of 2 to 12 does not exhibit liquid crystallinity. However, considering compatibility with the compound (I) having liquid crystallinity, c is preferably in the range of 4 to 10,
More preferably, it is in the range of 6 to 9. Compound (I
I) can also be synthesized by any method, for example, by subjecting compound (II) to an esterification reaction between 1 equivalent of 4-cyanophenol and 1 equivalent of 4- (n- (meth) acryloyloxyalkoxy) benzoic acid. Can be synthesized. In this esterification reaction, as in the case of synthesizing the compound (I), the benzoic acid is generally activated with an acid chloride, sulfonic anhydride or the like, and is reacted with 4-cyanophenol. In addition, the above benzoic acid is combined with 4% by using a condensing agent such as DCC (dicyclohexylcarbodiimide).
-A cyanophenol may be reacted.

[0007] The low molecular weight compound having an optically active site used in the present invention refers to a low molecular weight compound having an optically active site having a molecular weight of 1
A compound of 500 or less is meant. This low-molecular compound is used mainly for the purpose of inducing a twist in the positive uniaxial nematic liquid crystal property expressed by the compound (I) and the compound (II). As long as this object is achieved, the compound (I) and the compound (II) are compatible with each other in a solution state or a molten state, and a desired twist can be induced in the mixture without impairing the nematic liquid crystallinity of the mixture. The type of the low-molecular compound is not particularly limited as long as it is a compound. It is essential that the low-molecular compound used to induce twist in the liquid crystal has at least some chirality in the molecule. Accordingly, examples of the optically active low molecular weight compound usable in the present invention include compounds having one or more asymmetric carbon atoms, chiral amines, chiral sulfoxides, etc., having an asymmetric point on a hetero atom. Certain compounds or compounds having axial asymmetry such as cumulene and binaphthol can be exemplified. More specifically, a commercially available chiral nematic liquid crystal such as Merck S-8
11 and the like. Films having a large twist angle using the liquid crystal composition of the present invention, particularly, when obtaining a cholesteric film having a short pitch such that the selective reflection band is near the wavelength of visible light, it is necessary to induce a strong twist. In addition, the amount of the low-molecular compound having an optically active site to be contained in the liquid crystal composition must be increased as compared with a system having less twist. In particular, a compound having a small unit absolute film thickness and a small twist angle per unit addition amount (hereinafter referred to as a twisting force) defined below for a low molecular compound having an optically active site is contained in the liquid crystalline composition of the present invention. When a low molecular compound having an optically active site to be selected is selected, it is necessary to further increase the ratio of the low molecular weight compound having an optically active site in the liquid crystal composition. Twist angle (unit: degree) = (total angle at which the liquid crystal director rotates from one surface of the film to the other surface) Twist force (unit: degree / μm ·%) = (twist angle) / (film Absolute film thickness) / (weight percentage of compound having an optically active site to be formed into a liquid crystalline composition) However, depending on the properties of the selected low molecular compound having an optically active site, compound (I) and compound (II) )), The nematic liquid crystal formed may be destroyed, the orientation may be reduced, or if the compound is non-polymerizable, the curability of the liquid crystalline composition may be reduced, and the reliability of the cured film may be reduced. Furthermore, the use of a large amount of a compound having an optically active site leads to an increase in the cost of the composition. Therefore, when producing a cholesteric film of a short pitch, it is preferable to select a compound having a large twisting power as a low molecular compound having an optically active site to be contained in the liquid crystal composition of the present invention. It is preferable to use a low molecular weight compound (III) having axial asymmetry in the molecule as represented by the general formula (3) or (4).

In the general formula (3) or (4) representing the low molecular compound (III), R ⁴ represents hydrogen or a methyl group. Y is any one of the expressions (i) to (xxiv) shown above, and among them, the expressions (i), (ii), and (ii)
Preferably, it is one of i), (v) and (vii). Also, d and e indicating the chain length of the alkylene group
Can individually take any integer in the range of 2 to 12, but is preferably in the range of 4 to 10, and 6 to 9
More preferably, it is within the range. The value of d or e is 0
Alternatively, the compound of general formula (3) or (4), which is 1, lacks stability, is susceptible to hydrolysis, and has high crystallinity. On the other hand, a compound having a value of d or e of 13 or more has a melting point (T
m) is low. These compounds have reduced compatibility with the compounds (I) and (II) exhibiting liquid crystallinity, and may cause phase separation or the like depending on the concentration. Low molecular compound (I
II) can be synthesized by any method. For example,
One equivalent of (R)-(+)-or (S)-(-)-1,1'-bi-2-naphthol and two equivalents of 4- (m- (meth) acryloyloxyalkoxy) group The low molecular weight compound (III) can be synthesized by an esterification reaction with a carboxylic acid having the compound or a carboxylic acid having a 4-alkoxy group. Incidentally, the low molecular weight compound (III) in which Y in the general formula (3) or (4) is the above formula (i) or (ii), and Z in the formula is hydrogen, in other words, the general formula (3)
Alternatively, the low molecular weight compound (III) in which Y in (4) is a phenylene group has one equivalent of (R)-(+)-or (S)-(-)-1,1′-
It can be produced by an esterification reaction between bi-2-naphthol and 2 equivalents of 4- (m- (meth) acryloyloxyalkoxy) benzoic acid or 4-alkoxybenzoic acid. In this esterification, as in the case of synthesizing the compound (I) or the compound (II), the carboxylic acid as a raw material is activated by introducing it into an acid chloride or a sulfonic anhydride, and this is reacted with 4-cyanophenol. However, in order to prevent racemization of the low molecular weight compound (III), a method of directly reacting the starting carboxylic acid with 4-cyanophenol using a condensing agent such as DCC (dicyclohexylcarbodiimide) can be used. Adoption is particularly preferred.

In the liquid crystal composition of the present invention, the relative amounts of the compound (I) and the compound (II) are optimal in consideration of the molecular length of each compound used and the properties of the liquid crystal film to be finally produced. Although the value is determined, generally, the weight ratio of the compound (I): the compound (II) is from 99: 1 to 50:
50, preferably 95: 5 to 60:40, more preferably 90:10 to 65:35, most preferably 85: 1.
It is selected in the range of 5 to 70:30. The amount of compound (I) contained in the liquid crystal composition is determined by comparing compound (I) with compound (I).
If it exceeds 99% by weight of the total amount of I), satisfactory crystallinity cannot be imparted to the film obtained from the liquid crystalline composition due to the relatively high crystallinity of compound (I). . On the other hand, if the above amount is less than 50% by weight, the isotropic transition temperature (TI) of the liquid crystal composition is lowered, so that the liquid crystal temperature range becomes extremely narrow, which is not preferable. The amount of the low-molecular compound or low-molecular compound (III) having an optically active site to be blended in the liquid crystal composition of the present invention, the twist-inducing ability inherent to the compound, and the cholesteric property of the finally obtained liquid crystal film are taken into consideration. The optimum value is determined by the above method. Generally, 0.01 to 60 parts by weight, preferably 100 parts by weight of the total amount of the compound (I) and the compound (II) constituting the liquid crystal composition of the present invention is preferable. Is 0.1 to 40 parts by weight, more preferably 0.5 to 3 parts by weight.
The amount of the low-molecular compound or low-molecular compound (III) having an optically active site is selected in an amount of 0 part by weight, most preferably 1 to 20 parts by weight. This compounding amount is 0.01
If the amount is too small, sufficient cholesteric properties may not be imparted to the liquid crystalline composition. If the amount is more than 60 parts by weight, the orientation of molecules may be impaired, which may adversely affect photocuring.

Compounds other than those described above can be added to the liquid crystalline composition of the present invention as long as the object of the present invention is not impaired. Examples of the compound that can be added include, for example, a polyester (meth) acrylate obtained by reacting (meth) acrylic acid with a polyester prepolymer obtained by condensing a polyhydric alcohol and a monobasic acid or a polybasic acid;
Polyurethane (meth) acrylate obtained by reacting a compound having a polyol group and two isocyanate groups with each other and then reacting the reaction product with (meth) acrylic acid; bisphenol A type epoxy resin, bisphenol F type epoxy Resin, novolak type epoxy resin, polycarboxylic acid polyglycidyl ester, polyol polyglycidyl ether, aliphatic or alicyclic epoxy resin,
Photopolymerizable compounds such as epoxy (meth) acrylates obtained by reacting (meth) acrylic acid with epoxy resins such as amine epoxy resins, triphenolmethane type epoxy resins, and dihydroxybenzene type epoxy resins; acrylic and methacrylic groups And the like. The amount of these compounds to be added to the liquid crystal composition of the present invention is selected within a range that does not impair the purpose of the present invention, and is generally 40% by weight or less, 20% by weight or less of the liquid crystal composition of the present invention. It is. The addition of these compounds improves the curability of the liquid crystal composition of the present invention, increases the mechanical strength of the cured film, and improves the stability of the liquid crystal.

The liquid crystalline composition of the present invention can be cured by irradiation with an electron beam in the absence of a photoreaction initiator. If necessary, one or more photoreaction initiators may be used. , 0.01 to 20% by weight, preferably 0.1 to
It can be added to the liquid crystalline composition of the present invention in an amount of 10% by weight, more preferably 0.5 to 5% by weight. Examples of usable photoreaction initiators include benzyl (also called bibenzoyl), benzoin isobutyl ether, benzoin isopropyl ether, benzophenone, benzoyl benzoic acid, methyl benzoyl benzoate, 4-benzoyl-4'-methyldiphenyl sulfide, and benzyl methyl. Ketal, dimethylaminomethylbenzoate, 2
-N-butoxyethyl-4-dimethylaminobenzoate, isoamyl p-dimethylaminobenzoate, 3,3 '
-Dimethyl-4-methoxybenzophenone, methylobenzoylformate, 2-methyl-1- (4- (methylthio) phenyl) -2-morpholinopropan-1-one, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) -butan-1-one, 1- (4-
Dodecylphenyl) -2-hydroxy-2-methylpropan-1-one, 1-hydroxycyclohexylphenylketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 1- (4-isopropylphenyl)- 2-hydroxy-2-methylpropan-1-one, 2-chlorothioxanthone, 2,4-diethylthioxanthone 2,4-diisopropylthioxanthone,
2,4-dimethylthioxanthone, isopropylthioxanthone, 1-chloro-4-propoxythioxanthone and the like can be mentioned. In addition, it is also possible to add a sensitizer other than the photoreaction initiator as long as the object of the present invention is not impaired.

When a liquid crystal film is obtained by using the liquid crystal composition of the present invention, any method can be adopted. For example, a method in which a liquid crystal composition in a molten state is cast on a support film, or A method such as lamination molding can be adopted. One suitable method for producing a liquid crystal film from the liquid crystal composition of the present invention is to dissolve the liquid crystal composition in a solvent, apply this solution on a support film or a substrate, and then form a coating layer. Is dried to evaporate the solvent,
Then, the dried film is heat-treated as necessary. Hereinafter, this method for producing a liquid crystal film will be described in detail. Solvent for preparing a solution Solvent for dissolving or dispersing the liquid crystal composition of the present invention,
For example, hydrocarbons such as benzene, toluene, xylene, n-butylbenzene, diethylbenzene, and tetralin, ethers such as methoxybenzene, 1,2-dimethoxybenzene, diethylene glycol dimethyl ether, acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclohexanone, , 4-pentanedione and other ketones, ethyl acetate, ethylene glycol monomethyl ether acetate, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, esters such as γ-butyrolactone, 2-pyrrolidone, N-methyl-2- Amide solvents such as pyrrolidone, dimethylformamide, dimethylacetamide, chloroform, dichloromethane, carbon tetrachloride, dichloroethane, tetrachloroethane , Tri-trichloroethylene, tetrachloroethylene, chlorobenzene, orthodichlorobenzene, etc., halogenated solvents, t-butyl alcohol, diacetone alcohol, glycerin, monoacetin, ethylene glycol, triethylene glycol, hexylene glycol, ethylene glycol monomethyl ether, ethyl cellosolve, butyl One or more of alcohols such as cellosolve and phenols such as phenol and parachlorophenol can be used. Even if only a single type of solvent is used, even if the solubility of the liquid crystalline composition is insufficient or the support film described below may be eroded, by mixing and using two or more types of solvents. This inconvenience can be avoided.
Among the above-mentioned solvents, preferred as a single solvent are a hydrocarbon-based solvent and a glycol monoether acetate-based solvent, and preferably as a mixed solvent medium,
It is a mixed system of ethers or ketones and glycols. The concentration of the solution cannot be specified unconditionally because it depends on the solubility of the liquid crystalline composition and the thickness of the liquid crystal film to be produced, but is usually 1 to 60% by weight, preferably 3 to 4% by weight.
It is adjusted in the range of 0% by weight. A surfactant or the like can be added to the solution of the liquid crystal composition to facilitate application. Examples of surfactants that can be added include cationic surfactants such as imidazoline, quaternary ammonium salts, alkylamine oxides and polyamine derivatives, polyoxyethylene-polyoxypropylene condensates, primary and secondary surfactants. Alcohol ethoxylate, alkylphenol ethoxylate, polyethylene glycol and its ester, sodium lauryl sulfate, ammonium lauryl sulfate, amine lauryl sulfate, alkyl-substituted aromatic sulfonate, alkyl phosphate, aliphatic or aromatic sulfonate formalin condensate, etc. Anionic surfactants, amphoteric surfactants such as laurylamidopropyl betaine and laurylaminoacetate betaine, and nonionic surfactants such as polyethylene glycol fatty acid esters and polyoxyethylene alkylamine Surface active agents include perfluoroalkyl sulfonates, perfluoroalkyl carboxylates, perfluoroalkyl ethylene oxide adducts,
Perfluoroalkyltrimethylammonium salts, perfluoroalkyl group / hydrophilic group-containing oligomers, perfluoroalkyl / lipophilic group-containing oligomers Perfluoroalkyl group-containing urethanes, and other fluorinated surfactants. The amount of the surfactant depends on the type of the surfactant, the type of the curable liquid crystal composition, the type of the solvent, and even the type of the support film to which the solution is applied. It is in the range from 10% to 10%, preferably from 100% to 5%, more preferably from 0.1 to 1% by weight of the composition.

[0013] Support film, support substrate and arrangement on them
The solution of the liquid crystal composition for imparting function is applied on a support film or a substrate. As the support film, for example, polyimide, polyamide imide, polyamide, polyether imide, polyether ether ketone, polyether ketone, polyketone sulfide, polyether sulfone, polysulfone, polyphenylene sulfide, polyphenylene oxide, polyethylene terephthalate, polybutylene terephthalate, Plastic films such as polyethylene naphthalate, polyacetal, polycarbonate, polyarylate, acrylic resin, polyvinyl alcohol, polypropylene, cellulose, triacetyl cellulose and partially saponified products thereof, epoxy resin and phenol resin can be used. These plastic films may be laminated films obtained by laminating two or more kinds of films, or may be uniaxially stretched or biaxially stretched films. Further, the support film can be subjected to a surface treatment such as a hydrophilic treatment or a hydrophobic treatment in advance. Depending on the composition of the liquid crystal composition contained in the solution, it is not necessary to separately impart an alignment ability to the support film, but it is preferable to impart an alignment ability to the support film before applying the solution. The orientation ability is imparted by laminating an orientation film on the support film or by rubbing the support film or the orientation film laminated on the support film. Alternatively, silicon oxide may be obliquely vapor-deposited on the support film to impart orientation ability. The alignment film is usually made of polyimide, polyamide, polyvinyl alcohol, etc., and the rubbing treatment is performed by winding a rubbing cloth selected from materials such as rayon, cotton, polyamide, etc. on a metal roll and rotating it in contact with the film. Alternatively, a method of rubbing the film surface with a rubbing cloth by transporting the film while fixing the roll is usually adopted. Instead of the above-described support film, a metal substrate such as aluminum, iron, or copper having a slit-shaped groove on the surface, or a glass substrate such as an alkali glass, a borosilicate glass, or a flint glass, whose surface is etched into a slit shape. It can also be used.

For applying the solution and applying the solution to the dried supporting film or supporting substrate, a spin coating method, a roll coating method, a printing method, an immersion pulling method, a curtain coating method (die coating method) and the like can be arbitrarily adopted. is there. The coating layer is then dried to evaporate the solvent in the coating layer. Air drying at room temperature, drying on a hot plate, drying in a drying oven, blowing hot or hot air, etc. are used to dry the coating film layer. It does not matter. Depending on the composition of the liquid crystal composition contained in the coating layer, the thermotropic liquid crystal or lyotropic liquid crystal is often formed in the process of drying the coating layer. In other words, the nematic orientation of the molecular arrangement is often completed at the time when the drying step is completed. However, in order to make the orientation of the liquid crystal more perfect, it is preferable to subject the dried coating layer to heat treatment after the drying step. A method of heating a liquid crystalline composition forming a coating layer to a liquid crystal state by heating the liquid crystal composition to a temperature higher than a liquid crystal transition point and maintaining this state for a predetermined time. For example, a method of lowering the temperature to a liquid crystal state after maintaining the liquid state and maintaining the state for a predetermined time can be used for the heat treatment of the dried coating film layer. The heat treatment of the dried coating film layer is usually performed in a temperature range of 40 ° C. to 220 ° C.
C. to 180.degree. C., more preferably 60.degree.
The range of ° C. is preferred. The treatment time depends on the composition of the liquid crystalline composition contained in the coating layer, but is usually in the range of 5 seconds to 2 hours, preferably 10 seconds to 40 minutes, particularly preferably 20 seconds to 20 minutes. If the heat treatment time is less than 5 seconds, molecules may not be sufficiently oriented, and heat treatment for more than 2 hours is unnecessary for molecular orientation.

Curing of the Coating Layer by Light Irradiation The light used for curing the coating layer can be selected arbitrarily.
For example, electron beams, ultraviolet rays, visible light rays, and infrared rays (heat rays) can be used depending on the situation. Usually, ultraviolet light or visible light is used, and the wavelength is 150 to 500 nm, preferably 250 to 450, more preferably 300 to 40.
Irradiation light of 0 nm is used. Light sources for this irradiation light include low-pressure mercury lamps (germicidal lamps, fluorescent chemical lamps, black lights), high-pressure discharge lamps (high-pressure mercury lamps, metal halide lamps), and short arc discharge lamps (ultra-high-pressure mercury lamps, xenon lamps, mercury xenon lamps) Lamp). Of these, the use of metal halide lamps, xenon lamps, high-pressure mercury lamps, etc. is recommended. At the time of light irradiation, a filter can be provided between the light source and the irradiation target, and the irradiation target can be exposed to light in a specific wavelength region. The irradiation light amount is adjusted depending on the composition of the liquid crystal composition forming the coating layer and the presence or absence of the initiator, but is generally from 2 to 5000 mJ /.
cm ^2, more preferably 10~3000mJ / cm ^2, more preferably in the range of 100 to 2000 mJ / cm ^2. The ambient temperature at the time of light irradiation is appropriately selected depending on the physical and chemical properties of the coating layer, but is usually 0 to
It is in the range of 200C, preferably 20-180C, more preferably 25-160C. However, for example, a liquid crystalline composition having a higher-order phase such as a smectic phase or a crystal phase in a low-temperature region near room temperature, and having a chiral nematic phase in a higher temperature region, by photocuring in a chiral nematic phase state. In the case of immobilization, it may be necessary to perform light irradiation at a temperature equal to or higher than the phase transition point between the higher-order phase and the chiral nematic phase. In the heat treatment step prior to photocuring, if the nematic phase was already fixed by supercooling, the curing rate of the liquid crystal phase was low, so the coating layer was reheated to have fluidity. Light irradiation is preferably performed later. Light irradiation may be repeated several times. For example,
The reaction rate of the photoreaction can be further improved by irradiating light once under heating to cure the coating layer to some extent, and then irradiating light again after cooling. Further, after light irradiation, heat treatment may be performed again, and so-called aging may be performed to further react unreacted sites. The atmosphere in which the light irradiation is performed is not particularly limited. However, if the coating layer is susceptible to curing inhibition by oxygen or ozone in the atmosphere, the coating layer and / or its supporting film may be colored by the influence of oxygen or ozone in the atmosphere,
The irradiation atmosphere is preferably an inert gas atmosphere such as a nitrogen gas. As long as the orientation of liquid crystal molecules in the coating layer is not hindered, instead of using an inert gas atmosphere, it is possible to cover the coating layer surface with a film having oxygen or ozone blocking ability and perform light irradiation. is there. In this case, as the blocking film, for example, a polyethylene terephthalate film, a polyethylene naphthalate film, a polyphenylene sulfide film, a polyarylate film, a polycarbonate film, a polyvinyl alcohol film, a polyvinyl acetate film, a polyethylene film, a polypropylene film, a polyvinyl chloride film, Polyvinylidene chloride film, polyamide film, polyimide film, polyethylene-vinyl acetate co-extruded film and the like can be used.

The liquid crystal film of the present invention has the compound (I) and the compound (II) molecules cholesterically oriented and has a positive birefringence. When using a support film or a support substrate to which an alignment ability has been imparted by a rubbing treatment or the like, and a liquid crystal film is prepared from the liquid crystal composition of the present invention, at the interface between the support film or the support substrate and the liquid crystal film, nematic alignment was performed. The axis of projection of the liquid crystal molecule director into the liquid crystal film plane (hereinafter, referred to as the alignment axis) basically matches the rubbing direction of the support film or the support substrate (hereinafter, referred to as the rubbing axis). And the rotation angle takes a value specific to the liquid crystal film. Various optical parameters such as the wavelength bandwidth of the cholesteric liquid crystal film according to the present invention, the film thickness and the number of twist turns can be adjusted depending on the application of the liquid crystal film, but the wavelength bandwidth of the selective reflection is usually in the range of 15 to 120 nm. The actual thickness of the liquid crystal layer is usually desirably 0.6 μm or more. Here, the wavelength bandwidth of the selective reflection refers to a wavelength range in which the reflectance due to the selective reflection becomes 70% or more when circularly polarized light in the same direction as the twist direction of the liquid crystal molecules forming the cholesteric alignment is incident on the liquid crystal film. Means that. If the wavelength bandwidth deviates from the above range, the liquid crystal layer itself may be bright but the reflected light may be dark, or vice versa, and the visibility may be degraded depending on the application. When the actual thickness of the liquid crystal layer is less than 0.6 μm, the selective reflection effect by cholesteric alignment may be reduced. Further, the number of twisted turns of the liquid crystal layer in the cholesteric liquid crystalline film is usually desirably 2 or more. If it is less than two turns, there is a possibility that the selective reflection effect by the cholesteric orientation cannot be sufficiently obtained.

[0017]

The compounds (I) and (II) of the present invention
And an optically active low-molecular compound, typically a compound (II
The cholesteric liquid crystal film obtained from I) is not only applied to the fields of optics and optoelectronics, but also exhibits a very beautiful color when its selective reflection wavelength is in the visible light range. It is also useful. Further, it can be used as a pigment, a color polarizing plate, a brightness enhancement film and a forgery prevention film, and exhibit excellent performance.

[0018]

EXAMPLES Examples will be described below, but the present invention is not limited to these examples. Example 1 Preparation of Compound (I) -a 4- (6 ) was added to 180 g of distilled and purified tetrahydrofuran.
-Acryloyloxyhexyloxy) benzoic acid 151.
3 g (518 mmol) and 1.5 g of 2,6-ditert-butyl-4-methylphenol were dissolved, and 70.1 g of diisopropylethylamine (543 mmo) was added thereto.
Prepare a solution to which l) has been added. While cooling a solution of 62.1 g (543 mmol) of methanesulfonyl chloride in tetrahydrofuran to −10 ° C. and stirring, the above solution was added dropwise over 30 minutes. After completion of the dropwise addition, the temperature of the reaction solution was raised to 0 ° C., and the mixture was further stirred for 15 minutes. Then, a solution of 29.87 g (246 mmol) of methylhydroquinone in tetrahydrofuran was added dropwise to the reaction solution. Thereafter, the reaction solution was stirred for 15 minutes, and then 3.0 g of 4-dimethylaminopyridine (2
5mmol) with 62.4 g (617m) of triethylamine.
mol) was added dropwise over 15 minutes. After the dropwise addition, the reaction solution was stirred at 0 ° C. for 1 hour, further heated to room temperature, and reacted under stirring for 5 hours. After completion of the reaction,
The mixture was diluted with 00 ml of ethyl acetate, transferred to a separating funnel and then separated with 1N hydrochloric acid, and the organic layer was washed with 1N hydrochloric acid, a saturated aqueous solution of sodium hydrogen carbonate and a saturated aqueous solution of magnesium sulfate. The organic layer was dehydrated and dried by adding 100 g of anhydrous magnesium sulfate and stirring at room temperature for 1 hour. The magnesium sulfate was separated by filtration, and concentrated by a rotary evaporator to obtain methylhydroquinone bis (4-
(6-Acryloyloxy hexyloxy) benzoic acid)
The ester was obtained as a crude product. The crude product was recrystallized from ethyl acetate / methanol to give methylhydroquinone bis (4- (6-acryloyloxyoxyhexyloxy) benzoic acid) ester (compound (I) -a).
146.9 g were obtained as white crystals (yield 85.2).
%). The purity by GPC of this compound was 98.7%. GPC uses tetrahydrofuran as an elution solvent, and is a packed column for high-speed GPC (TSKgelG-100).
0HXL) equipped with Tosoh GPC analyzer CCP &
8000 (CP-8000, CO-8000, UV-8
000). When this compound was observed on a Mettler hot stage under a polarizing microscope, it turned into a crystalline phase at room temperature and a nematic phase at around 85 ° C., and became an isotropic phase at around 115 ° C. when further heated. Preparation of Compound (II) -a Using the same method as in the synthesis of Compound (I) -a, 4- (6
-Acryloyloxyhexyloxy) benzoic acid
5 g (111 mmol), 4-cyanophenol
From 6 g (106 mmol) to 34.8 g of 4-cyanophenol 4- (6-acryloyloxyohexyloxy) benzoate (compound (II) -a, yield 84)
%). The purity of this compound by GPC was 99.3.
%Met. Preparation of Liquid Crystal Film 7.0 g of the above compound (I) -a, compound (II)-
a, 1.07 g, chiral dopant liquid crystal S-811
1.93 g (produced by Roddick) was weighed and dissolved in 90 g of N-methyl-2-pyrrolidone. 1.5 mg of a fluorine-based surfactant S-383 (produced by Asahi Glass) was added to this solution. The above solution was applied using a bar coater on a polyethylene naphthalate film (manufactured by Mitsubishi Diafoil) whose surface was rubbed with rayon cloth. After the application, the film is put into a clean oven set at 60 ° C., dried for 15 minutes, and then heat-treated in an oven set at 80 ° C. for 5 minutes, and from that temperature to 50 ° C. at about 1 ° C./min. The cholesteric alignment of the liquid crystal layer was completed by cooling. After the heat treatment, the film was taken out of the oven, cooled to room temperature, and irradiated with an electron beam (EB) at room temperature to obtain a liquid crystal film A. The EB irradiation was performed using an EB irradiation apparatus manufactured by Eye Electron Beam, at room temperature, in an atmosphere having an oxygen concentration of 0.20% and an acceleration voltage of 30 kV. The liquid crystal layer after the irradiation was hardened, and the surface hardness was about H to 2H in terms of pencil hardness. The liquid crystal film A has selective reflection light peculiar to cholesteric alignment when viewed obliquely, and the spectroscope V-5.
When the transmission spectrum was evaluated by 00 (manufactured by JASCO Corporation), a reduced area of transmitted light due to selective reflection was observed around 780 nm in the infrared region. Example 2 Preparation of Compound (III) -a 5.00 g (17.5 mmol) of (S)-(−)-1,1′-bi-2-naphthol (manufactured by Tokyo Chemical Industry, 99% ee of chiral purity), 4 −
8.96 g of n-octyloxybenzoic acid (35.8 mm
ol), a dichloromethane solution of dicyclohexylcarbodiimide (DCC, manufactured by Tokyo Chemical Industry) was added dropwise at 0 ° C., and the mixture was reacted at 0 ° C. for 1 hour, and then heated to room temperature for further 6 hours. The insoluble portion of the obtained reaction solution was separated by filtration, and the filtrate was washed with a saturated aqueous solution of ammonium chloride, dried over magnesium sulfate, and concentrated to obtain a crude esterified product. This was recrystallized with an acetone / methanol mixed system to obtain 11.2 g (yield 84%) of an ester as pale yellow crystals (compound (III) -a). Preparation of liquid crystal film 7.0 g of compound (I) -a obtained in Example 1, 7.0 g of compound (II) -a, and the above compound (III) -a
0.5 g of N-methyl-2-pyrrolidone 90
g. To this solution was added a fluorinated surfactant S-38.
3 (manufactured by Asahi Glass) was added in an amount of 0.05 mg. The above solution was applied using a spin coater on a polyethylene naphthalate film whose surface was rubbed with rayon cloth. After coating, the film was put into a clean oven set at 60 ° C. and dried for 15 minutes.
The cholesteric alignment of the liquid crystal layer was completed by cooling at a temperature of about 1 ° C./min to 50 ° C. in an oven set at 5 ° C. for 5 minutes. Thereafter, in exactly the same manner as in Example 1, the film was taken out of the oven, cooled to room temperature, and irradiated with an electron beam (EB) at room temperature to obtain a liquid crystal film B. The EB irradiation was performed using an EB irradiation apparatus manufactured by Eye Electron Beam, at room temperature, in an atmosphere having an oxygen concentration of 0.20% and an acceleration voltage of 30 kV. The liquid crystal layer after the irradiation was hardened, and the surface hardness was about H to 2H in terms of pencil hardness. The thickness of the liquid crystal layer of the liquid crystal film B was measured by a stylus type thickness gauge and found to be 1.2 μm. The liquid crystal film B has selective reflection light peculiar to the cholesteric orientation of orange color even from the front, and its transmission spectrum is evaluated by a spectroscope V-500 (manufactured by JASCO Corporation).
In the vicinity of m, a reduced area of transmitted light due to selective reflection was observed. Example 3 Methylhydroquinone bis (4- (9-acryloyloxynonyloxy) synthesized by the same method as in Example 1.
Benzoic acid) ester (compound (I) -b) 7.8 g,
4-cyanophenol 4- (3-acryloyloxypropyloxy) benzoate (compound (II)-
b) 2.2 g, the binaphthol derivative (compound (III) -a) 0.5 g prepared in Example 2, and the photoreaction initiator Irgacure 907 (manufactured by Ciba Geigy) 0.3 g
And 0.1 g of a sensitizer diethylthioxanthone was dissolved in 40 g of tetrachloroethane to prepare a solution. After applying the above solution using a die coater on a polyphenylene sulfide film (manufactured by Toray) whose surface has been rubbed with a nylon-6 cloth, the back surface of the film is attached to a blue plate glass substrate, and a glass substrate-film integrated product is applied. Was placed on a hot plate set at 80 ° C. and dried for 20 minutes. The cholesteric alignment of the liquid crystal layer had already been completed. After that, 5
Put into an oven set at 0 ° C., cool the atmosphere to the oven set temperature for 2 to 3 minutes while replacing the atmosphere with nitrogen until the oxygen concentration becomes 250 ppm or less, and then UV at that temperature.
Irradiation was performed to obtain a liquid crystal film C. A high-pressure mercury lamp was used as the UV light source, and the irradiation intensity was 120 W / cm ² .
The integrated irradiation amount during the irradiation time of 15 seconds was 1,260 mJ. The liquid crystal layer after irradiation was cured, and its surface hardness was about 2H in terms of pencil hardness. The liquid crystal film C exhibited almost the same optical characteristics as the liquid crystal film B prepared in Example 2, and was a cholesteric liquid crystal film having a center of selective reflection at 585 nm. The thickness of the liquid crystal layer of the liquid crystal film C was measured with a stylus-type thickness gauge, and was 1.7.
μm. Comparative Example 1 In the preparation of the liquid crystal film described in Example 1, except that Compound (II) -a was not used, a solution similar to that of Example 1 was prepared, and this solution was applied on a polyethylene naphthate film. When dried, microcrystals were formed on the entire surface of the film to make it cloudy, and even after heat treatment, the liquid crystal layer did not become smooth due to the crystals, and a uniform cholesteric film could not be obtained. Comparative Example 2 In the preparation of the liquid crystal film described in Example 1, except that the chiral dopant liquid crystal S-811 (manufactured by Roddick) was not used, a solution similar to that in Example 1 was prepared, and this solution was polyethylene naphthate. When applied on a film and dried, the resulting film takes a nematic hybrid orientation in which the directors of the liquid crystal molecules are nearly parallel to the film surface at the interface with the support film and gradually tilt in the film thickness direction. And no cholesteric film was obtained.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Toru Nakamura 8 Chidori-cho, Naka-ku, Yokohama-shi, Kanagawa Prefecture Inside the Central Research Laboratory, Nisseki Mitsui Co., Ltd. (72) Inventor Ryo Nishimura 8 Chidori-cho, Naka-ku, Yokohama-shi, Kanagawa Prefecture Address F-term (reference) in Nishiishi Mitsui Co., Ltd. Central Research Laboratory 4H027 BA02 BE05 BE06 CC04 CE03 CE05 DK03 DK05

Claims (3)

[Claims] 1. A compound represented by the following general formula (1)
(I) and a compound (II) represented by the following general formula (2)
And a low molecular weight compound having an optically active site, wherein the weight ratio of compound (I): compound (II) is 99: 1 to 5
0:50, and the content of the low-molecular compound is 100 parts by weight based on the total amount of the compound (I) and the compound (II).
A liquid crystalline composition in the range of 0.01 to 60 parts by weight. Embedded image (In the general formulas (1) and (2), R ¹ , R ² and R ³
Each independently represents hydrogen or a methyl group, X represents hydrogen,
It represents one selected from the group consisting of chlorine, bromine, iodine, an alkyl group having 1 to 4 carbon atoms, a methoxy group, a cyano group and a nitro group, and a, b and c each represent an integer of 2 to 12. ) 2. The liquid crystalline composition according to claim 1, wherein the low molecular compound is a compound (III) represented by the following general formula (3) or (4). Embedded image (In the general formulas (3) and (4), R ⁴ represents hydrogen or a methyl group, d and e each represent an integer of 2 to 12, and Y is selected from the following (i) to (xxiv). One of the divalent groups shown below.) Here, Z in the above (i) and (ii) represents one selected from the group consisting of hydrogen, chlorine, bromine, an alkyl group having 1 to 4 carbon atoms, a methoxy group, a cyano group and a nitro group. Embedded image 3. A liquid crystal film formed by forming a film of the liquid crystalline composition according to claim 1 or 2, by cholesteric aligning the molecules to fix the alignment, and thereafter hardening the film by light irradiation.