JP2007332275A - Liquid crystal composition, color filter and liquid crystal display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal composition from which a phase difference layer excellent in mechanical strength such as hardness and adhesion to a base material can inexpensively and easily be produced; and to provide a color filter using the composition, and a liquid crystal display using the color filter. <P>SOLUTION: The liquid crystal composition contains one or more kinds of crosslinkable liquid crystal molecules, a silane coupling agent containing a sulfide group in the molecular structure, a polyfunctional (meth)acrylate having an alcoholic hydroxy group and a polyfunctional (meth)acryloyl group in the molecular structure, and an isocyanate compound. The color filter 1 has the phase difference layer 4 obtained by coating and immobilizing the composition on a transparent substrate 2. The liquid crystal display 11 uses the color filter 1 as a display-side substrate 12. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a liquid crystal composition, a color filter having a retardation layer made of the liquid crystal composition, and a liquid crystal display device using the color filter.

  In recent years, liquid crystal display devices have a great advantage of being thin and light and have low power consumption, and thus are actively used in display devices such as personal computers, mobile phones, and electronic notebooks. These liquid crystal display devices perform light switching by utilizing the birefringence of the driving liquid crystal material. Therefore, the liquid crystal display device has a viewing angle dependency derived from the birefringence of the driving liquid crystal material, and various retardation layer forming films have been developed to solve this problem. This retardation layer-forming film is usually prepared by stretching a film of polyacrylate, polycarbonate, triacetyl cellulose or the like, and is placed outside a liquid crystal cell in which a driving liquid crystal material is sandwiched between two substrates. Recently, a method has been proposed in which a retardation layer is provided inside a liquid crystal cell using a crosslinkable liquid crystal material or a polymer liquid crystal material (see Patent Document 1 below). By installing the phase difference layer, a film becomes unnecessary, so that high mechanical strength and heat resistance can be obtained, and further moisture absorption deformation can be suppressed.

Moreover, in order to further improve the heat resistance and chemical resistance of these retardation layers, there is a method in which polyfunctional (meth) acrylate (see Patent Documents 2 and 3 below) is added to the polymerizable liquid crystal and cured. Proposed.
JP 2000-221506 A JP 2002-265421 A JP 2002-308832 A

  However, as described in Patent Document 2 or 3, the method in which polyfunctional (meth) acrylate is simply added to the polymerizable liquid crystal has weak adhesion between the retardation layer and the substrate, and is peeled off due to external stress. There was a problem such as. The present invention has been made in view of the above problems, and a liquid crystal composition capable of forming a retardation layer excellent in mechanical strength such as hardness and substrate adhesion, inexpensively and easily, and its use. It is an object of the present invention to provide a color filter and a liquid crystal display device using the color filter.

  The liquid crystal composition according to the present invention is obtained by polymerizing and fixing a silane coupling agent containing a sulfide group and an alcoholic polyfunctional molecule together with a crosslinkable liquid crystal molecule. Improves the vertical orientation and hardness of the retardation layer, and further improves mechanical properties such as durability and substrate adhesion of the retardation layer synergistically with the additive by adding an isocyanate compound. Is.

That is, the liquid crystal composition according to the present invention is
(1) One or more crosslinkable liquid crystal molecules, a silane coupling agent containing a sulfide group in the molecular structure, a polyfunctional molecule having an alcoholic hydroxyl group and a polymerizable functional group in the molecular structure, An isocyanate compound, and a liquid crystal composition comprising:
(2) The liquid crystal composition according to the above (1), wherein at least one of the crosslinkable liquid crystal molecules has one or more (meth) acryloyl groups in one molecule;
(3) The liquid crystal composition according to the above (1) or (2), wherein the polyfunctional molecule is a polyfunctional (meth) acrylate;
(4) The polyfunctional (meth) acrylate is 2-hydroxy 1-3 dimethacryloxy propane, 2-hydroxy 1-3 dimethacryloxy propane, 2-hydroxy, 1-acryloxy, 3-methacryloxy propane, ethylene bis. [Oxy (2-hydroxypropane-1,3-diyl)] dimethacrylate, (1-methyl-1,2-ethanediyl) bis [oxy (2-hydroxy-3,1-propanediyl)] diacrylate, bisphenol A The liquid crystal composition according to (3), which is one or more selected from the group consisting of -glycidyl methacrylate, bisphenol A-glycidyl acrylate, and pentaerythritol diacrylate monostearate;
(5) The liquid crystal composition according to the above (3), wherein the polyfunctional (meth) acrylate is pentaerythritol triacrylate;
(6) The liquid crystal composition according to (3), wherein the polyfunctional (meth) acrylate is dipentaerythritol hydroxypentaacrylate;
(7) The liquid crystal composition according to any one of (1) to (6), wherein the isocyanate compound has two or more isocyanate groups in the molecular structure;
(8) The liquid crystal composition according to any one of (1) to (7), wherein the silane coupling agent is contained in an amount of 1 to 20% by weight in terms of a formulation.
(9) The liquid crystal composition according to any one of (1) to (8), wherein the polyfunctional molecule is contained in an amount of 5 to 20% by weight in terms of a formulation.
(10) The liquid crystal composition according to any one of (1) to (9), wherein the isocyanate compound is contained in an amount of 1 to 20% by weight in terms of a formulation.
Is a summary.

The color filter according to the present invention and a liquid crystal display device using the color filter are as follows:
(11) A color filter in which at least a colored layer and a retardation layer are laminated on a transparent substrate, and the retardation layer is cured by the liquid crystal composition according to any one of (1) to (10) above. A color filter characterized by being formed by:
(12) The retardation layer coats the liquid crystal composition according to any one of (1) to (10) above on the colored layer, and irradiates the surface with active radiation to cure the crosslinkable liquid crystal molecules. The color filter according to (11), wherein the color filter is formed by:
(13) The above-mentioned crosslinkable liquid crystal molecule in which the retardation layer contains at least 92.9 to 70% by weight of (meth) acryloyl group in terms of the formulation, and 0.1 to 10% by weight of the photopolymerization initiator. And the liquid crystal composition containing 1 to 20% by weight of the silane coupling agent, 5 to 20% by weight of the polyfunctional molecule, and 1 to 20% by weight of the isocyanate compound is photocured and baked. The color filter according to the above (11) or (12), wherein the pencil hardness of the retardation layer formed is 2H or more according to an evaluation standard of JISK5600-5-4;
(14) The cross-linkable liquid crystal molecule containing a (meth) acryloyl group of at least 92.9 to 70% by weight as a phase difference layer, and 0.1 to 10% by weight of a photopolymerization initiator. And the liquid crystal composition containing 1 to 20% by weight of the silane coupling agent, 5 to 20% by weight of the polyfunctional molecule, and 1 to 20% by weight of the isocyanate compound is photocured and baked. The color filter according to any one of (11) to (13), wherein the color filter is formed and the peel strength of the retardation layer is 1 or less in accordance with the evaluation standard of JISK5600-5-6;
(15) The color filter according to any one of (11) to (14), wherein the retardation layer is homeotropically oriented;
(16) The color filter according to any one of (11) to (15) described above and a driving circuit side substrate including a liquid crystal driving electrode are disposed to face each other, and the color filter and the driving circuit side substrate are disposed. A liquid crystal display device in which a liquid crystal material for driving is enclosed between;
Is a summary.

In addition, some terms used in this specification are defined as follows.
The term “(meth) acryloyl group” is used as a general term for two functional groups, “acryloyl group” and “methacryloyl group”. Examples of acryloyl groups include acryloyloxy groups (acrylate groups), and examples of methacryloyl groups include methacryloyloxy groups (methacrylate groups). Similarly, “(meth) acrylate” means “acrylate” and “methacrylate”.

  The “liquid crystal composition” includes at least a crosslinkable liquid crystal molecule, a silane coupling agent having a sulfide group, an alcoholic polyfunctional molecule, and an isocyanate compound, and is used for forming a retardation layer. It means both a composition that is a mixture containing other substances and a composition that is in a solution state prepared by dissolving or suspending the above mixture in a solvent. In the present specification, the liquid crystal composition of the present invention which is the above-described “composition in a solution state” is also referred to as a “liquid crystal composition solution” for convenience.

  “Comparison value of compound” means that when the liquid crystal composition of the present invention is the above mixture, each compound when the total weight of each compound formulated as a substance constituting the mixture is 100 In the case where the liquid crystal composition of the present invention is a solution obtained by dissolving or mixing the above-mentioned composition with a solvent, the weight obtained by subtracting the weight of the solvent from the weight of the solution (that is, dissolved or suspended in the solvent). It means the weight ratio of each compound when the total weight of each compound before turbidity is taken as 100. In addition, in the present invention, the expression “% by weight” unless otherwise specified means a value in terms of a compound.

  The “retardation layer” means a layer having a retardation control function capable of optically compensating for a change in retardation of light.

  “Homeotropic alignment” refers to an alignment state in which the optical axes of liquid crystal molecules constituting the retardation layer rise perpendicularly or substantially perpendicularly to the substrate surface. Further, “the retardation layer is homeotropically aligned” means that liquid crystal molecules constituting the retardation layer are homeotropically aligned. In the present invention, the ideal homeotropic alignment of the liquid crystal molecules means that the xyz orthogonal coordinate is assumed in the x-axis direction when the xyz orthogonal coordinate is assumed with the thickness direction of the retardation layer as the z-axis. The case where the refractive index ny is substantially the same and the phase difference value when the measurement angle is 0 ° is 4 nm or less, preferably 3.5 nm or less, more preferably 3 nm or less.

The liquid crystal composition of the present invention is coated on a substrate such as a glass substrate, and the liquid crystal molecules are aligned and then cured, whereby the coating film has excellent hardness and substrate adhesion. Therefore, a color filter in which a retardation layer is formed from the liquid crystal composition of the present invention and a liquid crystal display device using this color filter as a display side substrate are inexpensive and have an excellent viewing angle improvement effect over a long period of time, hardness and There is an effect of exhibiting adhesion to the substrate.
In addition, the liquid crystal composition of the present invention improves the vertical alignment by adding a silane coupling agent containing a sulfide group to the crosslinkable liquid crystal molecules, and without using a vertical alignment film and a substrate (under The layer can be homeotropically (vertically) oriented regardless of the surface properties.
Furthermore, according to this invention, there exists an effect that compatibility with a crosslinkable liquid crystal molecule improves by using the polyfunctional molecule which has a hydroxyl group and a polymerizable functional group.

  From the viewpoint of improving the adhesion between the retardation layer having the liquid crystal composition fixed thereon and the substrate, for example, a method of separately forming an adhesive layer between the two can be employed. In this case, it is necessary to go through a process of coating and fixing the adhesive layer prior to the formation of the retardation layer, and the thickness of the entire color filter and the liquid crystal display device is increased. May occur and the optical characteristics of the color filter and the like may be deteriorated. On the other hand, by integrally mixing the silane coupling agent having the predetermined functional group in the liquid crystal composition as in the present invention, any of an increase in the number of steps, an increase in the layer thickness, and a decrease in the optical characteristics can be achieved. The effect of the present invention can be obtained without the above problem.

  The liquid crystal composition of the present invention comprises (1) a crosslinkable liquid crystal molecule, (2) a silane coupling agent containing a sulfide group in the molecular structure, and (3) an alcoholic hydroxyl group and a polymerizable functional group in the molecular structure. And (4) an isocyanate compound is added to (5) a solvent. Each of the above components will be specifically described below.

<About crosslinkable liquid crystal molecules>
As the crosslinkable liquid crystal molecule used in the liquid crystal composition of the present invention, a crosslinkable nematic liquid crystal can be used. As the crosslinkable nematic liquid crystal, for example, (meth) acryloyl group, epoxy group, octacene group, Monomers, oligomers, polymers and the like having at least one polymerizable group such as an isocyanate group can be mentioned. Examples of such a crosslinkable liquid crystal include one compound of compounds (I) represented by the following general formula (1) or a mixture of two or more compounds, and compounds (II) represented by chemical formulas 2 and 3. One kind of compound or a mixture of two or more kinds, or a combination thereof can be used. In particular, it is preferable that at least one kind of the crosslinkable nematic liquid crystal molecules constituting the crosslinkable liquid crystal molecules in the present invention has one or more (meth) acryloyl groups in one molecule.

In the general formula (1), R ¹ and R ² each represent hydrogen or a methyl group, but at least one of R ^{1 and} R ² is preferably hydrogen because of the wide temperature range showing the liquid crystal phase. More preferably, ¹ and R ² are both hydrogen. X may be any of hydrogen, chlorine, bromine, iodine, an alkyl group having 1 to 4 carbon atoms, a methoxy group, a cyano group, or a nitro group, but is preferably a chlorine or methyl group. Moreover, a and b which show the chain length of the alkylene group which is a spacer between the (meth) acryloyloxy group of both ends of the molecular chain of compound (I) and an aromatic ring are arbitrary integers in the range of 2-12 respectively. However, it is preferably in the range of 4-10, more preferably in the range of 6-9. The compound of the general formula (1) in which a = b = 0 is poor in stability, is susceptible to hydrolysis, and has high crystallinity. Further, the compound of the general formula (1) in which a and b are each 13 or more has a low isotropic phase transition temperature (TI). For this reason, both of these compounds are not preferable because the temperature range showing liquid crystallinity becomes narrow. In the above Chemical Formula 1, Chemical Formula 2, and Chemical Formula 3, monomers for the crosslinkable liquid crystal are exemplified, but oligomers and polymers of the crosslinkable liquid crystal can be appropriately selected from those conventionally used.

  In general, the retardation amount and orientation characteristics of the retardation layer are determined by the birefringence Δn of the crosslinkable liquid crystal molecules and the film thickness of the retardation layer, and the Δn of the crosslinkable liquid crystal molecules is about 0.03 to 0.20. Preferably, about 0.05 to 0.15 is more preferable. By achieving such a birefringence, a desired phase difference such as λ / 4 or λ / 2 is obtained when visible light having a wavelength λ is transmitted by applying a liquid crystal composition using a general coating apparatus. A retardation layer is formed.

  In the liquid crystal composition of the present invention, it is preferable that the crosslinkable liquid crystal molecules are blended so as to be 70% by weight or more, preferably 75% by weight or more in terms of a compound. By setting the content to 70% by weight or more, liquid crystallinity is improved, and occurrence of alignment failure in the retardation layer can be satisfactorily suppressed. However, when it is necessary to add a specific additive to the crosslinkable liquid crystal molecule or to add a further additive for imparting a specific function to the retardation layer formed using the liquid crystal composition of the present invention. The amount of crosslinkable liquid crystal molecules added is not limited to the above. In such a case, the addition amount of the crosslinkable liquid crystal molecules may be appropriately determined in consideration of the addition amount of other additives. For example, in the case of obtaining a so-called negative C plate that is generally formed by adding a chiral agent to be described later, it is not excluded that the addition amount of the crosslinkable liquid crystal molecules is less than 70% by weight.

<About positive C plate>
By fixing the crosslinkable liquid crystal molecules by vertical alignment (homeotropic alignment), the optical axis of the liquid crystal molecules faces the normal direction of the retardation layer and an extraordinary ray refractive index larger than the ordinary ray refractive index is obtained. A so-called positive C plate having the normal direction of the phase difference layer can be formed. In this case, a vertical alignment film may be formed in advance on the application surface of the liquid crystal composition, or a vertical alignment aid may be mixed with the liquid crystal composition.

  Examples of vertical alignment aids include surface coupling agents having vertically aligned alkyl or fluorocarbon chains such as lecithin and quaternary ammonium surfactants, HTAB (hexadecyl-trimethylammonium bromide), DMOAP (N, N-dimethyl-N-octadecyl-3-aminopropyltrimethoxysilyl chloride), N-perfluorooctylsulfonyl-3-aminopropyltrimethylammonium iodide, long-chain alkyl alcohol, silane polymer, and the like.

According to the liquid crystal composition according to the present invention, the sulfide group-containing silane coupling agent described later is added to the crosslinkable liquid crystal molecules, whereby the surface of the substrate or the like on which the colored layer is formed on the glass substrate. When the liquid crystal composition of the invention is applied, aligned, and cured, the crosslinkable liquid crystal molecules in the liquid crystal composition are stably homeotropically aligned without using the alignment film, regardless of the surface properties of the substrate. Can do. In particular, even when the substrate surface is washed and the properties of the substrate surface change, the liquid crystal composition of the present invention is directly applied to the substrate surface, and the crosslinkable liquid crystal contained in the composition The retardation layer can be formed without disturbing the molecular orientation.
Furthermore, it is clear from the knowledge of the present inventors that the effect of stabilizing the homeotropic alignment is synergistically enhanced by adding the vertical alignment aid. The specific mechanism of the synergistic effect is not necessarily clear, but at least a part of the sulfide-based silane coupling agent added to the liquid crystal composition is coupled with the vertical alignment aid, so that the group in the retardation layer is It is presumed that the regulating force for vertically aligning the crosslinkable liquid crystal molecules is exhibited not only for the liquid crystal molecules facing the material interface and the air interface but also for the whole including the intermediate portion of the retardation layer.

<About negative C plate>
On the other hand, in the case of forming a so-called negative C plate in which the optical axis of the liquid crystal molecules is parallel to the retardation layer and has an extraordinary ray refractive index smaller than the ordinary ray refractive index in the normal direction of the retardation layer, a crosslinkable nematic As the liquid crystal, a chiral nematic liquid crystal having a cholesteric regularity to which a chiral agent is added can be suitably used.

  The chiral agent is a low molecular weight compound having an optically active site, and a compound having a molecular weight of 1500 or less is preferable. The chiral agent is used for the purpose of inducing a helical pitch in the positive uniaxial nematic regularity expressed by the compound (I) shown in Chemical Formula 1 or the compounds (II) shown in Chemical Formula 2 and Chemical Formula 3. Examples of the chiral agent include the compounds shown in Chemical Formula 4 below, but the liquid crystallinity of the crosslinkable nematic liquid crystal having compatibility with the above compound (I) or compound (II) in a solution state or a molten state. As long as the helical pitch can be induced without impairing the structure, the compound is not limited to the compound shown in Chemical formula 4. However, those having a crosslinkable functional group at both ends of the molecule are preferred for obtaining an optical element having good heat resistance. A chiral agent is a compound having an optically active site in the molecule.

  Examples of the chiral agent that can be used in the present invention include a compound having one or more asymmetric carbons, a compound having an asymmetric point on a heteroatom such as a chiral amine, a chiral sulfoxide, or the like. And compounds having axial asymmetry such as binaphthol. For example, commercially available chiral nematic liquid crystal, more specifically, S-811 manufactured by Merck Co., etc. can be used. Depending on the nature of the selected chiral agent, nematic regularity may be destroyed and the orientation may be lowered.In the case of a non-polymerizable chiral agent, the curability of the crosslinkable liquid crystal is lowered, and the electrical reliability of the cured film is deteriorated. There is a risk of lowering the cost, and the use of a large amount of a chiral agent having an optically active site causes an increase in cost. Therefore, as the chiral agent used in the present invention, it is preferable to select a chiral agent having a large effect of inducing a helical pitch in the alignment of the liquid crystalline polymer. Specifically, the chiral agent is represented by the following general formulas (2) to (4). It is preferable to use a low molecular weight compound having an axial asymmetry in the molecule.

In the general formulas (2) to (4), R ⁴ represents hydrogen or a methyl group, and Y is any one of (i) to (xxiv) shown in the following chemical formulas 5 and 6. In particular, any one of formulas (i), (ii), (iii), (v) and (vii) is preferable. Further, it is more preferable that c and d, which indicate the repetition of the alkylene group, are each in the range of 2 to 12 individually. A compound in which the value of either or both of c and d is 0 or 1 lacks stability, is susceptible to hydrolysis, and has high crystallinity. On the other hand, a compound having a value of c or d of 13 or more has a low melting point (Tm). In other words, the use of a chiral agent in which both the values of c and d are in the above preferred range has the advantage that sufficient compatibility with the crosslinkable liquid crystal monomer exemplified by the compound (I) and the compound (II) can be obtained. is there.

  The optimum range of the amount of the chiral agent is appropriately determined in consideration of the ability to induce helical pitch and the degree of cholesteric regularity of the crosslinkable liquid crystal molecules contained in the finally obtained retardation layer. It varies greatly depending on the type of liquid crystal molecules. Specifically, the chiral agent is generally 0.01 to 30% by weight, preferably 0.1 to 20% by weight, and more preferably 0.5 to 15% by weight in terms of the compound. Is blended into A particularly preferable amount of the chiral agent is 1 to 15% by weight in terms of the compound. When the content of the chiral agent in the composition component is less than 0.01% by weight, the cholesteric regularity may not be sufficiently imparted to the crosslinkable liquid crystal molecules contained in the liquid crystal composition. In the case of exceeding, the alignment performance of the crosslinkable liquid crystal molecules in the liquid crystal composition is hindered, and when the liquid crystal composition is cured by crosslinking polymerization of the crosslinkable liquid crystal molecules, the curing rate is lowered or the crosslinking density is lowered. May cause problems. When the blending amount of the chiral agent is within the above preferable numerical range, both the orientation of the negative C plate and the crosslinking curability can be sufficiently enhanced, and good optical properties of the retardation layer can be obtained.

  The chiral agent used in the present invention is not particularly required to have crosslinkability. However, in consideration of the thermal stability of the obtained retardation layer, the chiral agent is polymerized with the above-described crosslinkable liquid crystal, and the cholesteric rule. It is preferable to use a crosslinkable chiral agent capable of fixing the property. In particular, it is preferable to have a crosslinkable functional group at both ends of the molecule in order to obtain an optical element having good heat resistance.

<About positive A plate>
When forming a so-called positive A plate in which the optical axis of the liquid crystal molecules is parallel to the retardation layer and has an extraordinary ray refractive index larger than the ordinary ray refractive index in the in-plane direction of the retardation layer, a rubbing treatment or the like is performed. Applying the alignment regulating force by the applied horizontal alignment film to the crosslinkable liquid crystal molecules or adding the leveling agent to suppress the surface free energy of the crosslinkable liquid crystal molecules against the air interface to horizontally align the molecules Can do.

<Silane coupling agent>
A silane coupling agent is blended in the liquid crystal composition of the present invention. As the silane coupling agent, those containing a sulfide group as a functional group in the molecular structure (that is, a sulfide-based silane coupling agent) are preferable. Used. By blending a silane coupling agent having a sulfide group into the liquid crystal composition, the effect of improving the hardness and substrate adhesion of the retardation layer synergistically with the alcoholic polyfunctional molecule described above is exhibited.

  Furthermore, in the present invention, the effect of improving the orientation of the crosslinkable liquid crystal molecules can also be enjoyed as an effect of the sulfide-based silane coupling agent. Examples of this type of silane coupling agent include bis [3- (triethoxysilyl) propyl] tetrasulfide (KBE-846 manufactured by Shin-Etsu Chemical Co., Ltd.), bis [3- (triethoxysilyl) propyl] disulfide (Gelest). SIB1824.6), bis [m- (2-triethoxysilylethyl) tolyl] polysulfide (SIB1820.5 manufactured by Gelest), and the like. Two or more different silane coupling agents can be used in combination.

Two or more different silane coupling agents can be used in combination. The amount of the silane coupling agent is 1 to 20% by weight, preferably 1 to 10% by weight, and more preferably 1 to 5% by weight in terms of the amount of the liquid crystal composition. By adding 1% by weight or more, good vertical alignment of the crosslinkable liquid crystal molecules and sufficient substrate adhesion of the retardation layer can be obtained. Further, by adjusting the content to 20% by weight or less, it is possible to suppress the occurrence of liquid crystal orientation failure in the retardation layer and the decrease in electrical reliability of the retardation layer, which is favorable.
The compounding ratio of the crosslinkable liquid crystal molecules and the silane coupling agent used in the liquid crystal composition of the present invention is preferably 100: 1 to 9.5, more preferably 100: 1 to 5.5, and particularly preferably. 100: 1 to 2.0.

<About polyfunctional molecules>
The polyfunctional molecule used in the liquid crystal composition of the present invention is a molecule containing two or more polymerizable functional groups in the molecular structure. As the polyfunctional molecule, a polyfunctional molecule having an alcoholic hydroxyl group in the molecular structure is preferable. Can be used. The number of alcoholic hydroxyl groups contained in this polyfunctional molecule is usually 1 to 3, but 1 or 2 is preferable because it effectively prevents the orientation of the crosslinkable liquid crystal molecules from being disturbed.

  In addition, examples of the polymerizable functional group in the polyfunctional molecule include a (meth) acrylate group, an epoxy group, and an oxetane group. For reasons of high reactivity, (meth) acrylate is used as the polymerizable functional group. The polyfunctional (meth) acrylate to contain is preferable.

  Examples of the polyfunctional (meth) acrylate having an alcoholic hydroxyl group include monomers, oligomers and polymers having at least one alcoholic hydroxyl group in one molecule. As such an alcoholic polyfunctional (meth) acrylate, one compound or a mixture of two or more of the compounds (III) shown in the following chemical formula 7 can be used.

In the general formula shown in Chemical formula 7, m is 1 to 3, n is an integer of 2 or more, R ¹ is an organic hydrocarbon structure having 1 or more carbon atoms, and R ² is hydrogen or methyl group, respectively. . As the compound (III) shown in Chemical formula 7, a compound having any molecular weight can be used. Specifically, 2-hydroxy 1-3 dimethacryloxy propane, 2-hydroxy 1-3 dimethacryloxy propane, 2-hydroxy, 1-acryloxy, 3-methacryloxypropane, ethylenebis [oxy (2-hydroxypropane-1,3-diyl)] dimethacrylate, (1-methyl-1,2-ethanediyl) bis [oxy (2 -Hydroxy-3,1-propanediyl)] diacrylate, bisphenol A-glycidyl methacrylate, bisphenol A-glycidyl acrylate, pentaerythritol diacrylate monostearate, pentaerythritol triacrylate, dipentaerythritol hydroxypentaacrylate and the like. I can make it. From the viewpoint of compatibility with the crosslinkable liquid crystal, the molecular weight is preferably 1000 or less.

  The polyfunctional molecule needs to be added within a range that does not significantly impair the alignment of the liquid crystal, and is 5.0 to 20% by weight, preferably 10 to 15% by weight, in terms of the formulation of the liquid crystal composition. Add to. By setting the addition amount to 5.0% by weight or more, the hardness of the retardation layer can be sufficiently improved, and by setting this to 20% by weight or less, disorder occurs when aligning the crosslinkable liquid crystal. The fear is suppressed.

<About isocyanate compounds>
For the isocyanate compound blended in the liquid crystal composition of the present invention, both a linear isocyanate compound and an alicyclic isocyanate compound can be suitably used. In the liquid crystal composition of the present invention, those having two or more isocyanate groups in the molecular structure are preferably used.

  Specifically, for example, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, xylylene diisocyanate, hydrogenated xylylene diisocyanate, isophorone diisocyanate, 4,4′-diphenylmethane diisocyanate, toluidine diisocyanate, lysine diisocyanate, Examples include methylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, trimethylhexamethylene diisocyanate, triphenylmethane triisocyanate, and polymethylene polyphenyl polyisocyanate. An isocyanate compound can also be used in combination of 2 or more different types.

  Moreover, the preferable compounding quantity of an isocyanate compound is 1 to 20 weight% in the conversion value with respect to a compound in a liquid crystal composition, Preferably it is 5 to 10 weight%. By adding 1% by weight or more, it is possible to impart substrate adhesion to the retardation layer, and by adding 5% by weight or more, sufficient substrate adhesion exceeding the peel strength between other laminates is achieved. Obtainable.

  Other solute components optionally added to the liquid crystal composition of the present invention will be described below.

<About photopolymerization initiator>
When the liquid crystal composition of the present invention is polymerized and cured by irradiation with ultraviolet rays, a photopolymerization initiator may be added. As the photopolymerization initiator, a radical polymerization initiator can be used. Radical polymerization initiators are compounds that generate free radicals by the energy of ultraviolet rays, for example, benzophenone derivatives such as benzoin and benzophenone or derivatives thereof; xanthone and thioxanthone derivatives; chlorosulfonyl, chloromethyl polynuclear aromatic compounds, Halogen-containing compounds such as chloromethyl heterocyclic compounds and chloromethylbenzophenones; triazines; fluorenones; haloalkanes; redox couples of photoreductive dyes and reducing agents; organic sulfur compounds; peroxides . As photopolymerization initiators, Irgacure 184, Irgacure 369, Irgacure 651, Irgacure 907 (all manufactured by Ciba Specialty Chemicals), Darocur (Merck), Adeka 1717 (Asahi Denka Kogyo Co., Ltd.) ), 2,2′-bis (o-chlorophenyl) -4,5,4′-tetraphenyl-1,2′-biimidazole (manufactured by Kurokin Kasei Co., Ltd.), etc. Is preferred. These polymerization initiators can be used alone or in combination of two or more. When using 2 or more types together, it is preferable to combine initiators having different absorption wavelengths so as not to inhibit the absorption spectral characteristics.

  The photopolymerization initiator needs to be added within a range that does not greatly impair the alignment of the liquid crystal, and is 0.01 to 15% by weight, preferably 0.1 to 12% by weight, in terms of the formulation of the liquid crystal composition. More preferably, it is added so as to be 0.1 to 10% by weight, particularly 0.5 to 10% by weight. In addition to the photopolymerization initiator, a polymerization inhibitor, a sensitizer, and / or a surfactant can be added as long as the object of the present invention is not impaired.

  In the present invention, the content of the (meth) acryloyl group-containing crosslinkable liquid crystal molecule, sulfide group-containing silane coupling agent, alcoholic polyfunctional (meth) acrylate, isocyanate compound, and further the photopolymerization initiator is the preferred content described above. Can be adjusted as appropriate depending on the combination and the type of other compounds used. For example, the amount contained in the liquid crystal composition is 92.9 to 70% by weight of a crosslinkable liquid crystal containing a (meth) acryloyl group, and 1 to 20 sulfide containing silane coupling agents. It is preferable that they are 5 weight% of alcoholic polyfunctional (meth) acrylates, 1-20 weight% of isocyanate compounds, and 0.1-10 weight% of photoinitiators.

<About solvent>
The liquid crystal composition of the present invention can be used as a solution in which the solute component is dissolved in a solvent in order to improve applicability. The solvent is not particularly limited as long as it can dissolve the above-described solute components such as the crosslinkable liquid crystal molecules and the silane coupling agent and does not impair the performance of the counterpart material to be applied.

  Specifically, hydrocarbons such as benzene, toluene, xylene, n-butylbenzene, diethylbenzene, tetralin, ethers such as methoxybenzene, 1,2-dimethoxybenzene, diethylene glycol dimethyl ether, acetone, methyl ethyl ketone, methyl isobutyl ketone, Ketones such as cyclohexanone and 2,4-pentanedione, 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 Amide solvents such as 2-pyrrolidone, dimethylformamide, dimethylacetamide, chloroform, dichloromethane, carbon tetrachloride, dichloroethane Halogen solvents such as tetrachloroethane, trichloroethylene, tetrachloroethylene, chlorobenzene, orthodichlorobenzene, t-butyl alcohol, diacetone alcohol, glycerin, monoacetin, ethylene glycol, triethylene glycol, hexylene glycol, ethylene glycol monomethyl ether, ethyl cellosolve, One type or two or more types of alcohols such as butyl cellosolve and phenols such as phenol and parachlorophenol can be used.

  If only one type of solvent is used and the solubility of solute components such as crosslinkable liquid crystal molecules is insufficient, or if the material of the counterpart to be coated may be affected, two or more types of solvents are used. These disadvantages can be avoided by mixing and using. Among the above-mentioned solvents, preferred as a single solvent are a hydrocarbon solvent and a glycol monoether acetate solvent, and preferred as a mixed solvent is a mixed system of ethers or ketones and glycols. It is. The concentration of the compound component of the liquid crystal composition solution varies depending on the solubility of the compound component used in the liquid crystal composition in the solvent and the layer thickness desired for the retardation layer, but is usually 1 to 60% by weight, preferably It is in the range of 3 to 40% by weight. The concentration can be obtained by multiplying the weight obtained by subtracting the weight of the solvent from the weight of the liquid crystal composition solution by the total weight of the liquid crystal composition solution and multiplying by 100.

<About color filters using liquid crystal compositions>
The liquid crystal composition of the present invention can be used for forming a retardation layer for adjusting a viewing angle in a liquid crystal display device. The retardation layer is used for an optical element typified by a color filter of a liquid crystal display device, for example. Can be provided. Hereinafter, a color filter provided with a retardation layer will be exemplarily described based on the drawings.

  FIG. 1 shows an embodiment of a color filter 1 according to the present invention, 2 is a transparent substrate, 3 is a colored layer, and 4 is a retardation layer formed of the liquid crystal composition of the present invention. The color filter 1 includes a black matrix 5 (BM), a red (R) sub-pixel 6, a green (G) sub-pixel 7, and a blue (B) sub-pixel 8 on a transparent substrate 2. 3 and the retardation layer 4 formed using the liquid crystal composition of the present invention on the surface of the colored layer 3 is laminated.

  The transparent substrate 2 has optical transparency and is preferably optically isotropic, but a region having optical anisotropy or light shielding properties can be locally provided as necessary. The light transmittance can be appropriately selected according to the use of the color filter.

  Specifically, the transparent substrate 2 is made of an inorganic base material such as glass, silicon, or quartz, or an organic base material as listed below. Examples of organic base materials include acrylics such as polymethyl methacrylate, polyamide, polyacetal, polybutylene terephthalate, polyethylene terephthalate, polyethylene naphthalate, triacetyl cellulose, or syndiotactic polystyrene, polyphenylene sulfide, polyether ketone, polyether ether Ketone, fluororesin, polyether nitrile, etc., polycarbonate, modified polyphenylene ether, polycyclohexene, polynorbornene resin, etc., or polysulfone, polyethersulfone, polypropylene, polyarylate, polyamideimide, polyetherimide, polyether Examples of such materials include ketones and thermoplastic polyimide. Made of a tick can also be used. Also about the thickness of the transparent substrate 2, the thing of about 5 micrometers-3 mm is used according to a use, for example.

  On the transparent substrate 2, a black matrix (BM) 5 having a light-shielding property or light-absorbing property is provided in advance in a stripe shape, a mosaic shape, or the like in order to partition and form a predetermined arrangement position of RGB sub-pixels.

  On the transparent substrate 2, a color resist of each color of RGB is applied by a photolithography method, an ink jet method or the like, and further heated and baked, whereby a red (R) sub-pixel 6 and a green (G) sub-pixel 7. , Blue (B) sub-pixels 8 are sequentially provided to form the colored layer 3. The colored resist can be obtained by dispersing coloring materials of various colors such as pigments in a solvent.

The colored layer 3 is generally subjected to surface modification treatment such as UV cleaning treatment or corona treatment in order to remove impurities on the surface and improve wettability with respect to the liquid crystal composition. By performing such a treatment, the wettability of the liquid crystal composition applied to the colored layer surface, particularly the crosslinkable liquid crystal molecules contained therein, can be improved.
However, when such surface modification treatment is performed, the wettability of the colored layer surface is preferably improved, but the properties of the upper surface of the colored layer are greatly changed by the influence of ultraviolet irradiation. As a result, the cross-linkable liquid crystal contained in the liquid crystal composition is homeotropically (vertically) aligned without using an alignment film on the upper surface of the colored layer washed with an ultraviolet irradiation amount of 900 mJ / cm ² or more using a conventional liquid crystal composition. When it tried to do so, orientation was disordered and the phase difference layer which carries out a homeotropic orientation stably could not be obtained. On the other hand, in the case of the liquid crystal composition of the present invention, the crosslinkable liquid crystal in the liquid crystal composition can be obtained without the presence of the alignment film even on the upper surface of the colored layer washed with the ultraviolet irradiation amount of 900 mJ / cm ² or more. The molecules can be well aligned vertically, thereby providing a stable homeotropically aligned retardation layer, that is, a high-quality positive C plate.

  On the surface of the colored layer 3, the liquid crystal composition of the present invention is applied to form a liquid crystal coating film. For application of liquid crystal composition, gravure printing method, offset printing method, relief printing method, screen printing method, transfer printing method, electrostatic printing method, plateless printing method, gravure coating method, roll coating method A method such as a knife coating method, an air knife coating method, a bar coating method, a dip coating method, a kiss coating method, a spray coating method, a die coating method, a comma coating method, an ink jet method, a spin coating method, or a slit coating method can be used as appropriate. . After a liquid crystal coating film is formed on the colored layer 3, a predetermined orientation is imparted to the crosslinkable liquid crystal molecules contained in the liquid crystal coating film to crosslink the crosslinkable liquid crystal molecules.

  For example, when the liquid crystal coating film is used as the retardation layer 4 having a function as a positive C plate, the crosslinkable liquid crystal molecules are polymerized by homeotropic alignment of the crosslinkable liquid crystal molecules in the liquid crystal coating film. Giving homeotropic alignment to the crosslinkable liquid crystal molecules means that the liquid crystal coating film is heated by means of heating with infrared rays, etc., and the temperature of the liquid crystal coating film is changed so that the crosslinkable liquid crystal contained therein has a liquid crystal phase. The temperature (liquid crystal phase transition temperature) is equal to or higher than the temperature at which the crosslinkable liquid crystal becomes isotropic (liquid phase) (isotropic phase transition temperature).

In particular, according to the knowledge of the present inventors, it has been clarified that the vertical alignment can be improved by blending a sulfide-based silane coupling agent into the crosslinkable liquid crystal molecules. In particular, when UV cleaning treatment or surface modification treatment is performed on the surface of the colored layer 3 with an ultraviolet ray irradiation amount of 900 mJ / cm ² or more, the surface of the colored layer 3 is chemically uneven with physical irregularities or a liquid crystal composition. When the irregularity of the affinity is inevitably generated and the property changes greatly, even when the liquid crystal composition of the present invention is applied to the surface of the colored layer 3, it has excellent optical characteristics due to its sufficient vertical alignment. A positive C plate can be obtained. In other words, according to the liquid crystal composition of the present invention, a positive C plate having high optical properties due to high cleanliness and delamination strength of the colored layer 3 by UV cleaning treatment and surface modification treatment and good orientation. It is possible to obtain a color filter 1 having both functions and having such a positive C plate inside the transparent substrate 2 by a so-called in-cell type.

  Moreover, the polymerization (crosslinking polymerization) between the crosslinkable liquid crystal molecules imparted with alignment in the liquid crystal coating film is performed by applying light having a photosensitive wavelength such as a cross-linked liquid crystal molecule or a photopolymerization initiator contained in the liquid crystal composition to the liquid crystal coating film. It can be advanced by irradiation. At this time, the wavelength of light applied to the liquid crystal coating film is appropriately selected according to the absorption wavelength of the liquid crystal composition, but is generally about 200 to 500 nm. The light applied to the liquid crystal coating film is not limited to monochromatic light, and may be light having a certain wavelength range including the photosensitive wavelength of the liquid crystal composition.

  Thus, when the crosslinkable liquid crystal molecules contained in the liquid crystal coating film are polymerized, the liquid crystal coating film forms the retardation layer 4 and the color filter 1 is manufactured.

  In order to make the liquid crystal coating film into the retardation layer 4, the liquid crystal coating film is irradiated with light to advance the crosslinking polymerization reaction of the crosslinkable liquid crystal molecules, and further, the liquid crystal coating film is baked using an oven or the like. It may be done. By performing such firing, the retardation layer 4 can be further cured, and the color filter 1 in which the surface of the retardation layer 4 is cured can be obtained.

  Like the color filter 1 of the present embodiment, a so-called in-cell type retardation layer 4 is formed by applying a liquid crystal composition on the transparent substrate 2 and aligning and fixing the liquid crystal composition to form the retardation layer 4. Can be obtained. Thereby, compared to the conventional method of attaching a retardation film externally formed into a sheet shape to a transparent substrate with an adhesive or the like, the entire color filter 1 can be made thinner, and light scattering by the adhesive can be prevented. Since the retardation layer 4 is protected by the transparent substrate 2, effects such as improvement of heat resistance and suppression of moisture absorption deformation can be obtained.

<About color filter hardness and substrate adhesion>
In the color filter 1 of the present invention capable of improving the hardness of the retardation layer 4, the pencil hardness of the retardation layer 4 is preferably 2H or more based on the evaluation standard of JISK5600-5-4. Specifically, the pencil hardness of the retardation layer 4 is measured by the following test method.

  In this pencil hardness test method, a pencil consisting of an elongated cylindrical core and a wooden part surrounding the core is used, and a pencil sharpener removes the wooden part in the longitudinal direction from the end of the pencil. Expose the core about 6mm. At this time, care should be taken so that the pencil core is not damaged and a large chip is not formed, so that it becomes a substantially smooth cylindrical shape. Then, the tip of the pencil lead is brought into contact with the abrasive paper perpendicularly, and the pencil is moved back and forth with respect to the abrasive paper while maintaining an angle of about 90 °, thereby keeping the tip of the lead flat. Next, a substrate (sample substrate) serving as a sample whose hardness is to be measured is prepared in advance, and the sample substrate is placed in a pencil hardness tester provided with a pencil whose tip is flattened. The pencil hardness tester is set so that the load is 0 g when the tip of the pencil contacts the sample substrate at an angle of 1 °. Then, a load of 750 ± 10 g is applied to the pencil. After the tip of the pencil is placed on the sample substrate, the sample substrate is moved 7 mm at a speed of 0.5 to 1 mm / sec in a direction in which the pencil is inclined at 45 ± 1 °. After the tip of the pencil moves on the surface of the sample substrate, move the pencil on the sample substrate and inspect the condition of the surface (painted surface) part (test part) that was tested with the naked eye to determine the type of pencil indentation. Investigate. Pencil indentation may or may not cause an indentation. When an indentation occurs, it is classified and defined as follows (a) to (c) depending on the situation.

(A) Plastic deformation: Permanent indentation occurs in the coating film on the surface of the sample substrate, but there is no cohesive failure.
(B) Cohesive failure: The coating material used for forming the coating film is peeled off, scratched or broken by the naked eye on the surface of the sample substrate.
(C) Combination of the above: In the final stage, all defects may occur simultaneously.

  If none of the above indentations occur, the test is repeated with the pencil hardness scale raised, and if indentations occur, the test is repeated with the pencil hardness scale lowered. However, in such a repeated test, the position where the pencil tip and the sample substrate are brought into contact with each other is set to a different position so as not to overlap each other in each test.

  This pencil hardness test specifies the hardness of the pencil at which a scar having a length of at least 3 mm or more as the above-mentioned indentation is generated at the test site. The pencil hardness test is performed twice, and when the result of the two times differs by one unit or more, it is discarded and the test is performed again. That is, in the first pencil hardness test, when the pencil hardness is 2H, the scar length is 3 mm or more. In the second pencil hardness test, when the pencil hardness is 5H, the results of the two tests are discarded. Test again.

  Further, the color filter 1 of the present invention capable of improving the adhesion strength with the transparent substrate 2 and the colored layer 3 has a peel strength of the retardation layer 4 after the accelerated life test of 1 according to the evaluation standard of JISK5600-5-6. The following is preferable. The heating life test is performed for 1 hour at 100 ° C. and 100% RH using an accelerated life tester EHS-411M manufactured by Tabai. A specific peel test was performed in a grid pattern in each direction on a sample substrate on which the retardation layer 4 was formed in an environment of a temperature of 23 ± 2 ° C. and a humidity of about 50 ± 5% after the accelerated life test. Cut 6 times at 1 mm intervals to provide 5 × 5 grids. Next, a tape having an adhesive force of 10 ± 1 N per width of 25 mm and a width of about 25 mm is used, and the tape is pasted on the lattice so that the longitudinal direction of the tape is parallel to any side of the lattice, and is rubbed with a finger. . Furthermore, the edge of the tape is picked up, and the state of the lattice after being peeled off for 0.5 to 1 second at an angle of about 60 ° with respect to the non-adhesive surface of the tape is evaluated in the following six stages.

Evaluation criteria 0: A state in which the edge of the cut is completely smooth and there is no peeling of any lattice.
Evaluation criteria 1: Although there is a small peeling of the coating film at the intersection of cuts, it is less than 5% that is affected by the crosscut part.
Evaluation criteria 2: The coating film is peeled along the edge of the cut and / or at the intersection. The cross cut part is clearly affected by more than 5%, but not more than 15%.
Evaluation criteria 3: The coating film is partially or completely peeled along the edge of the cut, and / or various parts of the eyes are partially or completely peeled off. The cross-cut part is clearly affected by more than 15% but not more than 35%.
Evaluation criteria 4: The coating film is partially or completely peeled along the edge of the cut, and / or some eyes are partially or completely peeled off. The cross-cut portion is clearly affected by more than 35% but not more than 65%.
Evaluation criteria 5: When the degree of peeling exceeds Category 4 (including the state where the entire surface of the lattice is peeled).

<About other layers>
As shown in FIG. 1, a protective layer 9 and a spacer 10 may be sequentially provided on the surface of the retardation layer 4 as necessary. The protective layer 9 is made of a transparent resin material made of a material such as an acrylic, amide or ester polymer containing a polyfunctional acrylate, or a material such as an acrylic, amide or ester polymer containing a polyfunctional epoxy. It can be formed by applying a transparent resin paint to the surface of the retardation layer 4 and further drying and curing it. For the curing of the protective layer 9, for example, a method of irradiating UV light can be employed according to the properties of the transparent resin material.

  For the spacer 10, a photocurable photosensitive paint made of a material such as an acrylic, amide or ester polymer containing a polyfunctional acrylate is applied on the retardation layer 4, the protective layer 9, or the transparent substrate 2. Then, this is dried, and further, the paint is exposed and cured through a mask pattern corresponding to the position where the spacer 10 is to be formed, and then the uncured portion is removed by etching and the whole is baked.

  In addition, for the color filter 1, for example, a liquid crystal material formed between the transparent substrate 2 and the retardation layer 4 or on the retardation layer 4 so that the optical axis is parallel to the surface of the transparent substrate 2 is aligned. In addition, another phase difference control layer such as a positive A plate that is fixed may be provided.

  On the other hand, in the color filter 1, another functional layer 20 may be provided on the opposite side of the retardation layer 4 across the transparent substrate 2. Examples of the functional layer 20 include a transparent conductive film that forms an electric field with a driving electrode described later, a retardation control layer such as the positive or negative C plate or positive A plate, or a polarizing plate. can do. By selecting one or more of these and laminating them on the transparent substrate 2, a desired function is exhibited when the color filter 1 of the present invention is used as a liquid crystal display device described later.

<About liquid crystal display devices>
As shown in FIG. 2, the color filter 1 of the present invention encloses a driving liquid crystal material 14 between the driving circuit side substrate 13 to form a liquid crystal cell 15, thereby forming a liquid crystal cell 15. It can be used as the display-side substrate 12 installed (corresponding to the upper part in the figure). The retardation layer 4 of the color filter 1 constitutes a positive C plate in which the crosslinkable liquid crystal molecules are fixed in a state of being vertically aligned with respect to the transparent substrate 2 as described above. Here, the retardation layer 4 is disposed so as to be sandwiched between the transparent substrate 2 of the color filter 1 and the transparent substrate 31 constituting the driving circuit side substrate 13, and forms a so-called in-cell type.

  When the liquid crystal display device 11 is in the IPS mode, the linearly polarizing plate 23 of the display side substrate 12 and the linearly polarizing plate 32 of the driving circuit side substrate 13 are arranged so that their transmission axes are orthogonal to each other. .

  The driving circuit side substrate 13 includes a driving circuit 33 on the in-cell side of the transparent substrate 31 (side on which the driving liquid crystal material 14 is sealed) and a liquid crystal driving electrode 34 that controls the voltage load. Is provided. On the other hand, the display side substrate 12 includes a transparent conductive film 21, a positive A plate 22, and a linear polarizing plate 23 on the observer side of the transparent substrate 2 as the functional layer 20.

  Next, the retardation layer using the liquid crystal composition of the present invention will be described in detail by taking as an example the case where the liquid crystal molecules contained in the liquid crystal composition are homeotropically aligned to form the retardation layer as a positive C plate. .

Example 1
A mixture of compounds (a) to (d) shown in the following chemical formula 8 is used as a crosslinkable liquid crystal molecule, BHT (2,6-di-tert-butyl-4-hydroxytoluene) as a polymerization inhibitor, and Irga as a polymerization initiator. Cure 907 and other additives such as dodecanol were mixed to prepare a crosslinkable liquid crystal composition (composition A) having the following composition. The crosslinkable liquid crystal composition was prepared according to the description in JP-T-2004-524385. In addition, the weight ratio of each substance in the composition A shown below is the weight ratio of each substance to the total weight of the composition A.

Crosslinkable liquid crystal composition compound (a) 32.67% by weight
Compound (b) 18.67% by weight
Compound (c) 21.00% by weight
Compound (d) 21.00% by weight
Dodecanol 1.02% by weight
BHT 0.04% by weight
Irgacure 907 5.60% by weight

  For the above liquid crystal composition, bis [3- (triethoxysilyl) propyl] tetrasulfide (KBE-846 manufactured by Shin-Etsu Chemical Co., Ltd.) as a sulfide-based silane coupling agent is 1% by weight in terms of the amount of the compound, alcohol 5% by weight of pentaerythritol diacrylate monostearate (M-233 manufactured by Toagosei Co., Ltd.) as a functional polyfunctional molecule and 1% by weight of tolylene diisocyanate (Mitsui Chemicals Co., Ltd .: TDI) as an isocyanate compound were added. Thereafter, it was dissolved in propylene glycol monomethyl ether acetate (PGMEA) to obtain a liquid crystal composition having a concentration of 20%.

Next, a glass substrate (Corning Corp., 1737 glass) having a size of 100 × 100 mm and a thickness of 0.7 mm as a cleaned transparent substrate was applied to a spin coater (Mikasa Corp., 1H-360S). After setting, the liquid crystal composition was spin-coated on a glass substrate, and then dried under reduced pressure. Next, ultraviolet light having a wavelength of 365 nm is irradiated at 20 mW / cm ² for 10 seconds with an ultraviolet irradiation device having an ultrahigh pressure mercury lamp (manufactured by Harrison Toshiba Lighting Co., Ltd., “trade name TOSCURE 751”) to crosslink the crosslinkable liquid crystal. Were baked for 30 minutes using an oven to form a retardation layer having a thickness of 1.5 μm.

  With respect to the obtained retardation layer, the alignment state, hardness, and substrate adhesion of the crosslinkable liquid crystal molecules were measured as follows.

<Alignment state of crosslinkable liquid crystal molecules>
The alignment state of the crosslinkable liquid crystal molecules constituting the retardation layer was evaluated by measuring the retardation generated when light having a wavelength of 589 nm was transmitted through the retardation layer as follows. For measurement of the phase difference, RETS-1250AV manufactured by Otsuka Electronics Co., Ltd. was used.

  As shown in FIG. 3, the phase difference is assumed to have an x axis and a y axis orthogonal to each other on the surface of the phase difference layer, and a z axis perpendicular to the x axis and the y axis. And the phase difference of the optical element was measured about the z-axis direction and the direction inclined in the x-axis direction and the y-axis direction with respect to the z-axis. Whether the phase difference generated in the optical element shows symmetry with respect to the z axis when measured in the direction tilted in the x-axis direction or in the direction tilted in the y-axis direction. No was measured. Based on these measurement results, the quality of the orientation as to whether or not the crosslinkable liquid crystal molecules are homeotropically oriented was evaluated as follows. The results are shown in Table 1.

The phase difference shows symmetry in both the x-axis direction and the y-axis direction, and the value of the phase difference in the z-axis direction is 4 nm or less.
The phase difference exhibits symmetry in both the x-axis direction and the y-axis direction, or the phase difference value in the z-axis direction satisfies 4 nm or less.
The phase difference is disturbed in symmetry in both the x-axis direction and the y-axis direction, and the value of the phase difference in the z-axis direction is larger than 4 nm.

  In addition, regarding the above reference of 4 nm phase difference, when a phase difference is generated between two polarizing plates arranged in crossed Nicols and light is transmitted through the two polarizing plates, visually, The reference value of the phase difference that falls within such a range that light transmission cannot be confirmed is 4 nm.

<Hardness of retardation layer and substrate adhesion>
The measurement of the hardness of the retardation layer formed in the optical element was carried out by measuring the pencil hardness according to JIS K5600-5-4. The hardness of the retardation layer formed on the obtained optical element was evaluated as follows. The results are shown in Table 1.

Pencil hardness is equivalent to or harder than 2H (pencil hardness is 2H or more)
Pencil hardness is softer than 2H and harder than or equivalent to B ...
Pencil hardness is softer than that of B ...

  Further, the adhesion of the substrate after subjecting the obtained retardation layer to an accelerated life test for 1 hour at a temperature of 100 ° C. and a humidity of 100% was evaluated as follows according to JISK5600-5-6. The results are shown in Table 1.

Evaluation criteria based on measurement of peel strength is 0 or 1 (that is, 1 or less).
The evaluation standard based on the measurement of peel strength is 2.
Evaluation criteria based on measurement of peel strength is 3 to 5 (that is, 3 or more).

(Example 2)
A retardation layer was prepared and evaluated in the same manner as in Example 1 except that the equivalent value of the alcoholic polyfunctional molecule was changed to 10% by weight. The evaluation results are shown in Table 1.

(Example 3)
A retardation layer was produced and evaluated in the same manner as in Example 1 except that bisphenol A-glycidyl methacrylate (epoxy ester 3000M manufactured by Kyoeisha Chemical Co., Ltd.) was used as the alcoholic polyfunctional molecule. The evaluation results are shown in Table 1.

Example 4
A retardation layer was prepared and evaluated in the same manner as in Example 1, except that pentaerythritol triacrylate (M-305 manufactured by Toagosei Co., Ltd.) was used as the alcoholic polyfunctional molecule. The evaluation results are shown in Table 1.

(Example 5)
A retardation layer was prepared and evaluated in the same manner as in Example 1 except that 5% by weight of hexamethylene diisocyanate (Mitsui Chemicals: Takenate 700) was used as the isocyanate compound. The evaluation results are shown in Table 1.

(Example 6)
A retardation layer was produced in the same manner as in Example 1 except that 1% by weight of bis [3- (triethoxysilyl) propyl] disulfide (SIB1824.6 manufactured by Gelest) was used as a sulfide-based silane coupling agent. The evaluation results are shown in Table 1.

(Example 7)
A retardation layer was prepared and evaluated in the same manner as in Example 1 except that a colored layer was formed between the glass substrate and the retardation layer using the following colored resist. The evaluation results are shown in Table 1.

<Photoresist composition for red (R) colored pixel>
・ Red pigment: 5.0 parts by weight (CIPR254 (Ciba Specialty Chemicals, Chromophthal DPP Red BP))
・ Yellow pigment: 1.0 part by weight (CI PY139 (manufactured by BASF, Paliotor Yellow D1819))
・ Dispersant: 3.0 parts by weight (manufactured by Zeneca Corporation, Solsperse 24000)
・ Polyfunctional acrylate monomer: 4.0 parts by weight (Sartomer Co., Ltd., SR399)
-Polymer: 5.0 parts by weight (VR60 manufactured by Showa Polymer Co., Ltd.)
Photopolymerization initiator 1 1.4 parts by weight (Ciba Geigy, Irgacure 907)
Photopolymerization initiator 2 0.6 parts by weight (2,2′-bis (o-chlorophenyl) -4,5,4 ′, 5′-tetraphenyl-1,2′-biimidazole)
・ Solvent: 80.0 parts by weight Propylene glycol monomethyl ether acetate

The colored resist is applied onto the transparent substrate by spin coating, pre-baked at 90 ° C. for 3 minutes, alignment exposed (100 mJ / cm ² ), post-baked at 230 ° C. for 30 minutes, and film thickness 2 A red monochromatic colored layer having a thickness of 0.0 μm was formed. Subsequently, using a product name OC-2506 manufactured by Iwasaki Electric Co., Ltd. as an ultraviolet cleaning device, the colored layer was subjected to ultraviolet cleaning with an energy of 900 mJ / cm ² by ultraviolet rays having a wavelength of 254 nm.

(Reference Example 1)
A retardation layer was prepared and evaluated in the same manner as in Example 1 except that the equivalent value of the alcoholic polyfunctional molecule was changed to 3.0% by weight. The evaluation results are shown in Table 1.

(Reference Example 2)
A retardation layer was prepared and evaluated in the same manner as in Example 1 except that the equivalent value of the alcoholic polyfunctional molecule was changed to 25% by weight. The evaluation results are shown in Table 1.

(Reference Example 3)
A retardation layer was prepared and evaluated in the same manner as in Example 1 except that the conversion value of the isocyanate compound relative to the compound was 0.05% by weight. The evaluation results are shown in Table 1.

(Reference Example 4)
A retardation layer was prepared and evaluated in the same manner as in Example 1 except that the equivalent value of the isocyanate compound relative to the compound was 25% by weight. The evaluation results are shown in Table 1.

(Comparative Example 1)
A retardation layer was prepared and evaluated in the same manner as in Example 1 except that the alcoholic polyfunctional molecule was not used. The evaluation results are shown in Table 1.

(Comparative Example 2)
A retardation layer was prepared and evaluated in the same manner as in Example 1 except that the isocyanate compound was not used. The evaluation results are shown in Table 1.

(Comparative Example 3)
A colored layer and a retardation layer were prepared and evaluated in the same manner as in Example 7 except that the sulfide-based silane coupling agent was not used. The evaluation results are shown in Table 1.

(Comparative Example 4)
A retardation layer was prepared and evaluated in the same manner as in Example 1 except that 20% by weight of trimethylolpropane triacrylate (M-309 manufactured by Toagosei Co., Ltd.) was used in place of the alcoholic polyfunctional molecule. The evaluation results are shown in Table 1.

(Comparative Example 5)
A retardation layer was prepared and evaluated in the same manner as in Example 1 except that pentaerythritol tetraacrylate (Kyoeisha Chemical Co., Ltd., light acrylate PE-4A) was used instead of the alcoholic polyfunctional molecule. The evaluation results are shown in Table 1.

(Comparative Example 6)
A retardation layer in the same manner as in Example 1, except that 20% by weight of 2- (3,4 epoxycyclohexyl) ethyltrimethoxysilane (KBM-303 manufactured by Shin-Etsu Chemical Co., Ltd.) was used in place of the sulfide-based silane coupling agent. Were prepared and evaluated. The evaluation results are shown in Table 1.

(Comparative Example 7)
In the same manner as in Example 7 except that 20% by weight of 2- (3,4 epoxy cyclohexyl) ethyltrimethoxysilane (KBM-303 manufactured by Shin-Etsu Chemical Co., Ltd.) was used instead of the sulfide-based silane coupling agent, A retardation layer was prepared and evaluated. The evaluation results are shown in Table 1.

(Table 1)

  According to the liquid crystal composition of the present invention according to the above examples, reference examples and comparative examples, the retardation of the cross-linked liquid crystal molecules contained in the retardation layer is good for the retardation layer formed using the liquid crystal composition. It is understood that both the hardness of the retardation layer and the adhesion to the substrate can be improved while maintaining the same. In particular, the homeotropic orientation of the liquid crystal composition of the present invention when coated on a surface-modified substrate by adding a sulfide group-containing silane coupling agent is improved, and alcoholic polyfunctional molecules and It will be understood that the addition of the isocyanate compound synergistically improves the hardness of the retardation layer and the substrate adhesion.

It is a longitudinal cross-sectional view which shows one Example of the color filter of this invention. It is a longitudinal cross-sectional view which shows an example of the liquid crystal display device using the color filter of this invention. It is the figure which showed the phase difference measurement direction of the sample.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Color filter 2 Transparent substrate 3 Colored layer 4 Phase difference layer 11 Liquid crystal display device 12 Display side substrate 13 Driving circuit side substrate 14 Driving liquid crystal material 15 Liquid crystal cell

Claims (16)

  One or more crosslinkable liquid crystal molecules, a silane coupling agent having a sulfide group in the molecular structure, a polyfunctional molecule having an alcoholic hydroxyl group and a polymerizable functional group in the molecular structure, an isocyanate compound, A liquid crystal composition comprising:   The liquid crystal composition according to claim 1, wherein at least one of the crosslinkable liquid crystal molecules has one or more (meth) acryloyl groups in one molecule.   The liquid crystal composition according to claim 1, wherein the polyfunctional molecule is a polyfunctional (meth) acrylate.   The polyfunctional (meth) acrylate is selected from 2-hydroxy 1-3 dimethacryloxy propane, 2-hydroxy 1-3 dimethacryloxy propane, 2-hydroxy, 1-acryloxy, 3-methacryloxy propane, ethylene bis [oxy ( 2-hydroxypropane-1,3-diyl)] dimethacrylate, (1-methyl-1,2-ethanediyl) bis [oxy (2-hydroxy-3,1-propanediyl)] diacrylate, bisphenol A-glycidyl methacrylate The liquid crystal composition according to claim 3, wherein the liquid crystal composition is one or more selected from the group consisting of bisphenol A-glycidyl acrylate and pentaerythritol diacrylate monostearate.   The liquid crystal composition according to claim 3, wherein the polyfunctional (meth) acrylate is pentaerythritol triacrylate.   The liquid crystal composition according to claim 3, wherein the polyfunctional (meth) acrylate is dipentaerythritol hydroxypentaacrylate.   The liquid crystal composition according to claim 1, wherein the isocyanate compound has two or more isocyanate groups in the molecular structure.   The liquid crystal composition according to any one of claims 1 to 7, wherein the silane coupling agent is contained in an amount of 1 to 20% by weight in terms of a formulation.   The liquid crystal composition according to any one of claims 1 to 8, wherein the polyfunctional molecule is contained in an amount of 5 to 20% by weight in terms of a compound.   The liquid crystal composition according to any one of claims 1 to 9, wherein the isocyanate compound is contained in an amount of 1 to 20% by weight in terms of a compound.   A color filter in which at least a colored layer and a retardation layer are laminated on a transparent substrate, wherein the retardation layer is formed by curing the liquid crystal composition according to claim 1. A color filter characterized by being.   A retardation layer formed by coating the liquid crystal composition according to claim 1 on a colored layer, irradiating the surface with active radiation, and polymerizing the crosslinkable liquid crystal molecules. The color filter according to claim 11.   The retardation layer comprises at least 92.9 to 70% by weight of the crosslinkable liquid crystal molecules, 0.1 to 10% by weight of the photopolymerization initiator, and 1 to 20% by weight of the silane cup in terms of the compound equivalent. The liquid crystal composition containing a ring agent, 5 to 20% by weight of the polyfunctional molecule, and 1 to 20% by weight of the isocyanate compound is formed by photocuring and baking, and the pencil hardness of the retardation layer Is a color filter according to claim 11 or 12, which is 2H or more according to an evaluation standard of JISK5600-5-4.   The retardation layer comprises at least 92.9 to 70% by weight of the crosslinkable liquid crystal molecules, 0.1 to 10% by weight of the photopolymerization initiator, and 1 to 20% by weight of the silane cup in terms of the compound equivalent. The liquid crystal composition containing a ring agent, 5 to 20% by weight of the polyfunctional molecule, and 1 to 20% by weight of the isocyanate compound is formed by photocuring and baking, and the peel strength of the retardation layer Is a color filter according to any one of claims 11 to 13, which is 1 or less based on an evaluation standard of JISK5600-5-6.   The color filter according to claim 11, wherein the retardation layer is homeotropically oriented.   The color filter according to claim 11 and a driving circuit side substrate including a liquid crystal driving electrode are arranged to face each other, and the driving is performed between the color filter and the driving circuit side substrate. A liquid crystal display device encapsulating a liquid crystal material.

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