JP2004029634A - Liquid crystal substrate and liquid crystal display element - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a liquid crystal substrate permitting reduction in weight and film thickness, and delicate liquid crystal display without pixel deviation. <P>SOLUTION: The liquid crystal substrate contains a polymer resin containing an alicyclic structure, and a lamellar crystal compound, and a coefficient of linear expansion in the direction parallel to the substrate surface is made to 5 x 10<SP>-5</SP>/°C or smaller, and the whole light transmittance is made to 87% or higher with 0.5mm thickness. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a liquid crystal cell substrate used for a liquid crystal display device and the like and a liquid crystal display device using the same, and more particularly, to a liquid crystal substrate that can be reduced in weight and thickness and has no pixel shift.
[0002]
[Prior art]
A liquid crystal substrate is a component of a liquid crystal display element. In a liquid crystal display element, liquid crystal is sealed between two liquid crystal substrates.
Conventionally, glass has been mainly used as a liquid crystal substrate. However, there is a drawback that when the glass is thin, it is easily broken, when it is thick, it becomes heavy, and it is difficult to use it for a liquid crystal substrate for a liquid crystal display element having a curved surface due to lack of flexibility. Therefore, resins for optical materials having high transparency have been used.
[0003]
The present applicant has proposed a liquid crystal substrate made of a thermoplastic saturated norbornene resin (Japanese Patent Laid-Open No. 5-61026). According to this, since the transparency, heat resistance, moisture resistance, strength, and water resistance are excellent, a liquid crystal display element having a curved surface can also be manufactured.
However, in order to respond to recent demands for larger and higher-resolution liquid crystal display elements, even if the resin composition described in the above publication is molded and used as a liquid crystal substrate, problems such as pixel misalignment may occur. Remaining, further improvement was required.
[0004]
[Problems to be solved by the invention]
Accordingly, it is an object of the present invention to provide a liquid crystal substrate that can be reduced in weight and thickness and that can perform high-definition liquid crystal display without pixel shift.
[0005]
[Means for Solving the Problems]
The present inventors have conducted intensive studies to achieve the above object, and as a result, a liquid crystal substrate containing an alicyclic structure-containing polymer resin and a layered crystal compound, the total light transmittance of the substrate and the substrate By setting the coefficient of linear expansion in a direction parallel to the plane to a specific value, it was found that a high-definition liquid crystal display without pixel shift was possible, and further research based on this finding led to the present invention. It was completed.
[0006]
Thus, according to the present invention,
(1) A liquid crystal substrate comprising an alicyclic structure-containing polymer resin and a layered crystal compound, wherein the liquid crystal substrate satisfies the following requirements [1] and [2]:
[1] A coefficient of linear expansion in a direction parallel to the surface of the substrate is 5 × 10^-5/ ° C or lower,
[2] the total light transmittance at a thickness of 0.5 mm is 87% or more;
(2) The liquid crystal substrate according to (1), wherein the alicyclic structure-containing polymer resin contains a polar group.
(3) The liquid crystal substrate according to (2), wherein the content of the polar group in the alicyclic structure-containing polymer resin is 0.1 mmol / g or more.
(4) The liquid crystal substrate according to (1), wherein the layered crystal compound has been subjected to an organophilic treatment.
(5) A liquid crystal display device having the liquid crystal substrate according to any one of (1) to (4) is provided.
[0007]
BEST MODE FOR CARRYING OUT THE INVENTION
The liquid crystal substrate of the present invention comprises an alicyclic structure-containing polymer resin and a layered crystal compound, and satisfies the following requirements [1] and [2].
[1] The coefficient of linear expansion in the direction parallel to the plane is 5 × 10^-5/ ° C or lower.
[2] The total light transmittance at a thickness of 0.5 mm is 87% or more.
[0008]
The coefficient of linear expansion in the direction parallel to the plane of the liquid crystal substrate of the present invention is 5 × 10^-5/ ° C or lower, preferably 4.5 × 10^-5/ ° C or lower. By setting the linear expansion coefficient in the direction parallel to the surface of the liquid crystal substrate to the above range, when a liquid crystal is sealed in the substrate and a liquid crystal display device is produced, pixel shift due to environmental changes such as temperature and humidity can be reduced. Can be eliminated.
In the present invention, it is preferable that the coefficient of linear expansion in the thickness direction of the liquid crystal substrate is also in the same range as the direction parallel to the plane.
[0009]
The total light transmittance of the liquid crystal substrate of the present invention at a thickness of 0.5 mm is 87% or more, preferably 90% or more. By setting the total light transmittance of the liquid crystal substrate within the above range, a high-brightness liquid crystal display device can be provided.
[0010]
The alicyclic structure-containing polymer resin used in the present invention contains an alicyclic structure in a repeating unit of the polymer, and the alicyclic structure may be in any of the main chain and the side chain. . Examples of the alicyclic structure include a cycloalkane structure and a cycloalkene structure, and a cycloalkane structure is preferable from the viewpoint of thermal stability and the like. The number of carbon atoms constituting the alicyclic structure is usually 4 to 30, preferably 5 to 20, and more preferably 5 to 15. When the number of carbon atoms constituting the alicyclic structure is within this range, a material having excellent heat resistance and flexibility can be obtained.
The proportion of the repeating unit having an alicyclic structure in the alicyclic structure-containing polymer resin may be appropriately selected depending on the purpose of use, but is usually 50% by weight or more, preferably 70% by weight or more, more preferably 90% by weight or more. If the proportion of the repeating unit having an alicyclic structure is too small, heat resistance is undesirably reduced. The repeating unit other than the repeating unit having an alicyclic structure in the alicyclic structure-containing polymer resin is appropriately selected according to the purpose of use.
[0011]
Specific examples of the alicyclic structure-containing polymer resin include (1) a norbornene-based polymer, (2) a polymer of a monocyclic olefin, (3) a polymer of a cyclic conjugated diene, and (4) a vinyl alicycle. Formula hydrocarbon polymers, hydrides of (1) to (4), and mixtures thereof, and the like. Among these, hydrides of norbornene-based polymers, vinyl alicyclic hydrocarbon polymers and hydrides thereof are preferred from the viewpoints of heat resistance, mechanical strength, and the like.
[0012]
(1) Norbornene-based polymer
Examples of the norbornene-based polymer used in the present invention include a ring-opened polymer of a norbornene-based monomer, a ring-opened copolymer of a norbornene-based monomer and another monomer capable of being subjected to ring-opening copolymerization, a hydrogenated product thereof, and a norbornene-based polymer. Examples include an addition polymer of a monomer, and an addition copolymer of a norbornene-based monomer and another monomer copolymerizable therewith. Among these, from the viewpoints of heat resistance, mechanical strength, and the like, a hydrogenated ring-opened polymer of a norbornene-based monomer is most preferred.
[0013]
Examples of the norbornene-based monomer include bicyclo [2.2.1] -hept-2-ene (common name: norbornene) and its derivative (having a substituent on the ring), tricyclo [4.3.1].^2,5. 0^1,6] -Deca-3,7-diene (commonly used dicyclopentadiene) and its derivatives, tetracyclo [7.4.1^10,13. 0^1,9. 0^2,7] -Trideca-2,4,6,11-tetraene (also referred to as 1,4-methano-1,4,4a, 9a-tetrahydrofluorene: common name methanotetrahydrofluorene) and its derivative, tetracyclo [4.4.1^2,5. 1^7,10. 0] -dodeca-3-ene (common name: tetracyclododecene) and its derivatives.
Examples of the substituent include an alkyl group, an alkylene group, a vinyl group, an alkoxycarbonyl group, and the like. The norbornene-based monomer may have two or more of these. Specifically, 8-methyl-tetracyclo [4.4.1]^2,5. 1^7,10. 0] -dodec-3-ene, 8-ethyl-tetracyclo [4.4.1^2,5. 1^7,10. 0] -dodec-3-ene, 8-methylidene-tetracyclo [4.4.1^2,5. 1^7,10. 0] -dodec-3-ene, 8-ethylidene-tetracyclo [4.4.1^2,5. 1^7,10. 0] -dodec-3-ene, 8-methoxycarbonyl-tetracyclo [4.4.1^2,5. 1^7,10. 0] -dodec-3-ene, 8-methyl-8-methoxycarbonyl-tetracyclo [4.4.1^2,5. 1^7,10. 0] -dodec-3-ene and the like.
These norbornene monomers may be used alone or in combination of two or more.
[0014]
These ring-opening polymers of norbornene-based monomers or ring-opening copolymers of norbornene-based monomers and other monomers capable of ring-opening copolymerization are prepared by polymerizing monomer components in the presence of a known ring-opening polymerization catalyst. Can be obtained. Examples of the ring-opening polymerization catalyst include a catalyst comprising a metal halide such as ruthenium and osmium and a nitrate or acetylacetone compound, and a reducing agent, or a metal halide such as titanium, zirconium, tungsten, and molybdenum or acetylacetone. A catalyst comprising a compound and an organoaluminum compound can be used.
Examples of other monomers capable of ring-opening copolymerization with the norbornene-based monomer include, for example, monocyclic cycloolefin-based monomers such as cyclohexene, cycloheptene, and cyclooctene.
[0015]
A ring-opening polymer hydride of a norbornene-based monomer is usually added to a polymerization solution of the above-mentioned ring-opening polymer by adding a known hydrogenation catalyst containing a transition metal such as nickel or palladium to form a carbon-carbon unsaturated bond into a hydrogen. Can be obtained.
[0016]
An addition polymer of a norbornene-based monomer or an addition (co) polymer of a norbornene-based monomer and another monomer copolymerizable therewith can be used to convert these monomers into a known addition polymerization catalyst, for example, titanium, zirconium or vanadium. It can be obtained by (co) polymerization using a catalyst comprising a compound and an organoaluminum compound.
[0017]
Other monomers copolymerizable with the norbornene-based monomer include, for example, ethylene, propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 1-decene, 1-dodecene, 1-tetradecene, 1- Α-olefins having 2 to 20 carbon atoms such as hexadecene, 1-octadecene and 1-eicosene, and derivatives thereof; cyclobutene, cyclopentene, cyclohexene, cyclooctene, 3a, 5,6,7a-tetrahydro-4,7-methano Cycloolefins such as -1H-indene and derivatives thereof; non-conjugated dienes such as 1,4-hexadiene, 4-methyl-1,4-hexadiene, 5-methyl-1,4-hexadiene and 1,7-octadiene And the like are used. Of these, α-olefins, particularly ethylene, are preferred.
[0018]
These other monomers copolymerizable with the norbornene-based monomer can be used alone or in combination of two or more. When the addition copolymerization of a norbornene-based monomer and another monomer copolymerizable with the norbornene-based monomer, the ratio of the structural unit derived from the norbornene-based monomer to the structural unit derived from the other copolymerizable monomer in the addition copolymer is used. However, it is appropriately selected so that the weight ratio is usually in the range of 30:70 to 99: 1, preferably 50:50 to 97: 3, more preferably 70:30 to 95: 5.
[0019]
(2) Monocyclic cyclic olefin polymer
As the monocyclic cycloolefin polymer, for example, an addition polymer of a monocyclic cycloolefin monomer such as cyclohexene, cycloheptene, or cyclooctene can be used.
[0020]
(3) Cyclic conjugated diene polymer
As the cyclic conjugated diene-based polymer, for example, a polymer obtained by 1,2- or 1,4-addition polymerization of a cyclic conjugated diene-based monomer such as cyclopentadiene and cyclohexadiene, and a hydride thereof can be used. .
[0021]
(4) Vinyl alicyclic hydrocarbon polymer
Examples of the vinyl alicyclic hydrocarbon polymer include, for example, polymers of vinyl alicyclic hydrocarbon monomers such as vinyl cyclohexene and vinyl cyclohexane and hydrides thereof; and vinyl aromatic compounds such as styrene and α-methyl styrene. A hydride of an aromatic ring portion of a polymer of a monomer; and a vinyl alicyclic hydrocarbon polymer or a vinyl aromatic monomer, and another monomer copolymerizable with these monomers. Any of a random copolymer with a monomer, a copolymer such as a block copolymer, and a hydride thereof may be used. Examples of the block copolymer include diblocks, triblocks, and multi-blocks or gradient block copolymers, and are not particularly limited.
[0022]
In the present invention, when an alicyclic structure-containing polymer resin having a polar group is used as the alicyclic structure-containing polymer resin, the affinity with the layered crystal compound can be improved, and the obtained liquid crystal substrate This is preferable because the linear expansion coefficient can be reduced without impairing the total light transmittance.
[0023]
Examples of the type of the polar group include a hetero atom, an atomic group having a hetero atom, and the like. Examples of the hetero atom include an oxygen atom, a nitrogen atom, a sulfur atom, a silicon atom, and a halogen atom.From the viewpoint of dispersibility with the layered crystal compound and compatibility with other resins, oxygen atom and nitrogen Atoms are preferred. Specific examples of the polar group include a carboxyl group, a carbonyloxycarbonyl group, an epoxy group, a hydroxyl group, an oxy group, an ester group, a silanol group, a silyl group, an amino group, a nitrile group, and a sulfone group.
[0024]
Examples of a method for causing a polar group to be contained in the alicyclic structure-containing polymer resin include, for example, (1) an unmodified polymer obtained by polymerizing a monomer having no polar group in the norbornene-based monomer; A method of reacting (modifying) a compound having a polar group, (2) selecting a norbornene-based monomer having no polar group and a norbornene-based monomer having a polar group from among the norbornene-based monomers described above, and sharing them. A method of polymerizing, (3) a polymer obtained by polymerizing a norbornene-based monomer having no polar group among the above-mentioned norbornene-based monomers, a polymer obtained by polymerizing a norbornene-based monomer having a polar group, or A modification obtained by reacting a compound having a polar group with a non-modified polymer obtained by polymerizing a norbornene monomer having no polar group (modification reaction). And a method of mixing the polymer, but is not particularly limited.
[0025]
The method for introducing a polar group by a modification reaction is not particularly limited, and examples thereof include a method in which an ordinary modification reaction is performed. Specifically, chlorinated products of alicyclic structure-containing polymer resins, chlorosulfonated products, graft-modified products of a polar group-containing unsaturated compound, and the like, and preferably graft-modified products of a polar group-containing unsaturated compound are preferable. . Examples of the unsaturated compound containing a polar group include unsaturated epoxy compounds such as glycidyl acrylate, glycidyl methacrylate, glycidyl p-styrylcarboxylate, allyl glycidyl ether, and glycidyl ether of 2-methylallyl glycidyl ether; acrylic acid, methacrylic acid Unsaturated carboxylic acid compounds such as, α-ethylacrylic acid, maleic acid, fumaric acid, itaconic acid; unsaturated carboxylic anhydride compounds such as maleic anhydride, chloromaleic anhydride, butenylsuccinic anhydride; monomethyl maleate and maleic acid Unsaturated ester compounds such as dimethyl acid and glycidyl maleate; unsaturated alcohol compounds such as allyl alcohol, 2-allyl-6-methoxyphenol and 4-allyloxy-2-hydroxybenzophenone; Rushiran, trimethylsilylacetylene, 5-trimethylsilyl-1,3-cyclopentadiene, 3-trimethylsilylallyl alcohol, unsaturated silane compounds, such as trimethylsilyl methacrylate; and the like. Among these, unsaturated epoxy compounds and unsaturated carboxylic anhydride compounds are preferable in terms of reactivity with a curing agent described below. In order to efficiently graft copolymerize a polar group-containing unsaturated compound, it is usually preferable to carry out the reaction in the presence of a radical initiator. As the radical initiator, for example, organic peroxides, organic peresters and the like are preferably used.
[0026]
In the present invention, the content of the polar group in the alicyclic structure-containing polymer resin is preferably 0.01 mmol / g or more, more preferably 0.01 mmol / g to 0.8 mmol / g, and particularly preferably 0.1 mmol / g to 0.8 mmol / g. The range is from 01 mmol / g to 0.5 mmol / g. By setting the content of the polar group in the above range, the affinity with the layered crystal compound can be improved. In addition, the resulting liquid crystal substrate can be prevented from being colored or deteriorated due to a change in the use environment, and has excellent dimensional stability due to a change in the use environment. In the case of the modification reaction (1) described above, the content of the polar group depends on the introduction ratio of the polar group-containing unsaturated compound due to the modification. In the case of (3), it can be appropriately controlled by the mixing ratio between the alicyclic structure-containing polymer resin containing no polar group and the alicyclic structure-containing polymer resin containing the polar group. it can.
[0027]
The molecular weight of the alicyclic structure-containing polymer resin used in the present invention is appropriately selected depending on the purpose of use, but the gel permeation chromatography of a cyclohexane solution (a toluene solution when the polymer resin does not dissolve) is used. When the weight average molecular weight in terms of polyisoprene or polystyrene measured by a graph method is in the range of usually 5,000 to 500,000, preferably 8,000 to 200,000, more preferably 10,000 to 100,000. Furthermore, the mechanical strength and the moldability of the resin are highly balanced, which is preferable.
[0028]
The glass transition temperature (Tg) of the alicyclic structure-containing polymer resin used in the present invention may be appropriately selected depending on the purpose of use, but is preferably 80 ° C or higher, more preferably 130 ° C to 250 ° C. Range. Within this range, there is no deformation or stress even when used at high temperatures, and the durability is excellent.
[0029]
The layered crystal compound used in the present invention refers to a compound having a multilayer structure composed of a layered crystal (or a crystal layer). (1) The crystal layers are bonded by van der Waals force or hydrogen bonding force. And (2) a cation exists between the crystal layers, and the crystal layers charged to a negative charge are coupled to each other with a weak electrostatic force via the cations. it can.
[0030]
Specific examples of the layered crystal compound include graphite, TiS₂, NbSe₂, MoS₂Transition metal dichalcogenides such as CrPS₄Divalent metal phosphorus chalcogenides, such as MoO₃, V₂O₅Oxides of transition metals such as; oxyhalides such as FeOCl, VOCl, and CrOCl; Zn (OH)₂, Cu (OH)₂Hydroxide; Zr (HPO₄)₂・ NH₂O, Ti (HPO₄)₃・ NH₂O, Na (UO₂PO₄) · NH₂Phosphates such as O; Na₂Ti₃O₇, KTiNbO₅, Rb_xMn_xTi₂-XO₄Titanates such as; Na₂U₂O₇, K₂U₂O₇Uranate such as; KV₃O₈, K₃V₅O₁₄, CaV₆O₁₆・ NH₂O, Na (UO₂V₃O₉) · NH₂Vanadates such as O; KNb₃O₃, K₄Nb₆O₁₇Niobate such as; Na₂W₄O₁₃, Ag₄W₁₀O₃₃Tungstates such as; Mg₂Mo₂O₇, Cs₂Mo₅O₁₆, Cs₂Mo₇O₂₂, Ag₄Mo₁₀O₃₃Molybdates such as montmorillonite, saponite, hyderite, hectorite, nontronite, stevensite, trioctahedral vermiculite, dioctahedral vermiculite, muscobite, phylogobite, biotite, lepidolite, balagonite, Tetrasilicic mica, kaolinite, halloysite, dickite, H₂SiO₅, H₂Si₁₄O₂₉・ 5H₂Examples include silicates such as O and minerals composed of silicates, and from the viewpoint of heat resistance, mechanical strength, dispersibility, and the like, silicates, phosphates, molybdates, and the like are preferable, Silicates are most preferred.
[0031]
In the present invention, in order to improve dispersibility, it is preferable that these layered crystal compounds are previously subjected to an organophilic treatment with a cationic surfactant or the like. Examples of the cationic surfactant include R¹R²R³R⁴N⁺X⁻There is a quaternary ammonium salt represented by Where R¹, R², R³And R⁴May be the same or different and each represents a saturated or unsaturated hydrocarbon group having 1 to 30 carbon atoms. Specifically, methyl, ethyl, propyl, butyl, pentyl, hexyl, 2-ethylhexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, hexadecyl, saturated aliphatic hydrocarbon groups such as octadecyl, lauryl, oleyl and the like There are unsaturated aliphatic hydrocarbon groups, aromatic hydrocarbon groups such as phenyl and benzyl, and the like. X⁻Is, for example, Cl⁻, Br⁻, NO₃ ⁻, OH⁻, CH₃COO⁻Etc. There are anions.
[0032]
The weight ratio of the alicyclic structure-containing polymer resin to the layered crystal compound is usually in the range of 99.99 / 0.01 to 50/50, preferably in the range of 99.5 / 0.5 to 70/30. , More preferably in the range of 99/1 to $ 80/20. The average value of the major axis of the layered crystal compound is usually 0.01 to 10 μm, preferably 0.02 to 5 μm, more preferably 0.02 to 3 μm. When the weight ratio and the average value of the major axis fall within the above ranges, the resulting liquid crystal substrate is excellent in heat resistance, mechanical strength, and the like.
[0033]
To the alicyclic structure-containing polymer resin used in the present invention, if necessary, various additives such as a phenol-based or phosphorus-based antioxidant, an antistatic agent, and an ultraviolet absorber may be added. Since the liquid crystal is deteriorated by ultraviolet rays, it is preferable to add an ultraviolet absorber. As the ultraviolet absorber, a benzophenone-based ultraviolet absorber, a benzotriazole-based ultraviolet absorber, an acrylonitrile-based ultraviolet absorber, or the like can be used. The amount of these additives is usually 10 to 10,000 ppm, preferably 100 to 5,000 ppm. When the substrate is formed by the solution casting method, it is preferable to add a leveling agent to reduce the surface roughness. As the leveling agent, for example, a fluorine-based nonionic surfactant, a special acrylic resin-based leveling agent, a coating-based leveling agent such as a silicone-based leveling agent can be used, and among them, those having good compatibility with a solvent are preferable. The amount is usually 5 to 10,000 ppm, preferably 10 to 5,000 ppm.
[0034]
The method of compounding the alicyclic structure-containing polymer resin, the layered crystal compound, and the various additives is not particularly limited as long as it can be uniformly mixed into the alicyclic structure-containing polymer resin. 1) a method of melt-mixing an alicyclic structure-containing polymer resin, a layered crystal compound, and various additives using a Brabender, an extruder, a roll, or the like; (2) an alicyclic structure-containing polymer resin, layered A method of blending each of the crystalline compound and various additives with a solution, removing the solvent, and then melt-mixing the layered crystalline compound using an extruder, a roll, or the like is used.
[0035]
The liquid crystal substrate of the present invention is obtained by blending an alicyclic structure-containing polymer resin, a layered crystal compound, and various additives, followed by molding. As the molding method, for example, any of a heat-melt molding method and a solution casting method can be used, but it is preferable to use a heat-melt molding method from the viewpoint of reducing volatile components in the liquid crystal substrate. The heat-melt molding method can be further classified into an extrusion molding method, a press molding method, an inflation molding method, an injection molding method, a blow molding method and the like. Among these methods, in order to obtain a liquid crystal substrate excellent in mechanical strength, surface accuracy, and the like, it is preferable to use melt extrusion, particularly melt extrusion using a T-die. The molding conditions are appropriately selected depending on the purpose of use and the molding method. In the case of melt extrusion molding, the cylinder temperature is appropriately set within a range of preferably 100 to 400 ° C, more preferably 170 to 300 ° C.
[0036]
The liquid crystal substrate of the present invention is basically composed of an alicyclic structure-containing polymer resin and a layered crystal compound. In actual use, a transparent electrode layer, a liquid crystal alignment layer , A gas barrier film, a deflector, a retardation film and the like are laminated. Further, a spacer for providing a space for enclosing the liquid crystal between the two liquid crystal substrates may be laminated. In order to reduce the deterioration due to the permeation of oxygen and increase the durability, an adhesive layer or the like is provided between the liquid crystal substrate and the transparent electrode layer or on the side opposite to the bonding surface between the substrate and the transparent electrode layer. It is desirable to laminate a gas barrier material such as polyvinylidene chloride and polyvinyl alcohol via the above. What laminated | stacked these may also be called a liquid crystal substrate.
[0037]
The liquid crystal display device of the present invention has the liquid crystal substrate of the present invention. In general, a liquid crystal display element is configured by appropriately assembling components such as a polarizing plate, a liquid crystal cell, and a retardation compensating plate such as a reflecting plate and a retardation plate as necessary, and incorporating a driving circuit. FIG. 1 shows a layer configuration example of the liquid crystal display element of the present invention. FIG. 1 shows a schematic view of a reflection type liquid crystal display element provided with a reflection plate. However, the present invention is not limited to the reflection type, but can be applied to a transmission type liquid crystal display element. Has a structure in which there is no reflector.
[0038]
The liquid crystal display element 1 includes a liquid crystal cell 2 and a polarizing plate. The liquid crystal cell 2 has two liquid crystal substrates 21 on which a transparent conductive film 22 made of an ITO (indium oxide / tin) film or the like and an alignment film 23 are formed facing each other. A liquid crystal 24 is sealed in a space sealed by a seal material 26 formed on both end surfaces of the liquid crystal 21 together with spacers 25 such as plastic beads dispersed in an appropriate number. An upper polarizer 31 and a lower polarizer 32 are attached to the two liquid crystal substrates 21, respectively, and the lower polarizer 32 is further laminated with the reflection plate 17.
[0039]
In the liquid crystal display element of the present invention, in the case of a reflection type liquid crystal display element, although it has two upper and lower polarizing plates 31 and 32 in FIG. 1, it may be constituted by only one upper polarizing plate 31. . The material of the polarizer film is roughly classified into a polyhalogen polarizing film, a dye polarizing film, a metal polarizing film, and the like, and any of these materials can be used as the polarizer layers for the polarizing plates 31 and 32.
[0040]
The spacer 25 is for keeping the gap between the alignment films 23, that is, the gap between cells constant, and is usually made of plastic beads or silica spheres.
As the transparent conductive film 22, usually, an ITO (indium oxide / tin) film is used.
The alignment film 23 determines the display performance of the liquid crystal display device, and a polyimide-based material is generally used as the material of the alignment film.
[0041]
【Example】
The present invention will be described in more detail with reference to Reference Examples, Examples and Comparative Examples, but the present invention is not limited to the following Examples. Parts and percentages are by weight unless otherwise specified.
The evaluation in this example is performed by the following method.
(1) Molecular weight
It is measured by gel permeation chromatography (GPC) using tetrahydrofuran (THF) as a solvent, and the weight average molecular weight (Mw) in terms of standard polystyrene is determined.
(2) Glass transition temperature (Tg)
It is measured using differential scanning calorimetry (DSC) based on JIS K7121.
(3) Linear expansion coefficient
The temperature is measured in the range of 20 ° C to 70 ° C according to JIS K7197.
(4) Total light transmittance of liquid crystal substrate
It is measured using Nippon Denshoku Industries turbidity meter NDH-300A based on ASTM D1003.
(5) Pixel shift
The temperature of the manufactured liquid crystal substrate is raised from 20 ° C. to 150 ° C. in 10 minutes, and maintained at 150 ° C. for 30 minutes. Then, after that, it is moved to a place of 20 ° C. and cooled for 30 minutes. After this operation was repeated three times, a liquid crystal cell was formed using the substrate, a liquid crystal display element was formed, and the display state of the liquid crystal of the obtained liquid crystal display element was visually checked. To see.
[0042]
(Reference Example 1) Production of an alicyclic structure-containing polymer containing no polar group
Under a nitrogen atmosphere, in 500 parts of dehydrated cyclohexane, 0.82 part of 1-hexene, 0.15 part of dibutyl ether and 0.30 part of triisobutylaluminum were put in a reactor at room temperature and mixed. Tetracyclo [4.4.1^2,5. 1^7,10. 0] -dodec-3-ene (tetracyclododecene, hereinafter abbreviated as “TCD”) 80 parts and tetracyclo [7.4.1^10,13. 0^1,9. 0^2,7120 parts of -trideca-2,4,6,11-tetraene (methanotetrahydrofluorene, hereinafter abbreviated as "MTF") and 80 parts of tungsten hexachloride (0.7% toluene solution) were taken for 2 hours. And added continuously for polymerization. 1.06 parts of butyl glycidyl ether and 0.52 parts of isopropyl alcohol were added to the polymerization solution to inactivate the polymerization catalyst and terminate the polymerization reaction.
[0043]
Next, 270 parts of cyclohexane was added to 100 parts of the reaction solution containing the obtained ring-opening polymer, and 5 parts of a nickel-alumina catalyst (manufactured by Nikki Chemical Co., Ltd.) was further added as a hydrogenation catalyst. The mixture was heated to a temperature of 200 ° C. while being pressurized and stirred, and reacted for 4 hours to obtain a reaction solution containing 20% of a hydrogenated TCD / MTF ring-opening copolymer containing no polar group. After removing the hydrogenation catalyst by filtration, an antioxidant (manufactured by Ciba Specialty Chemicals; Irganox 1010) was added to the resulting solution and dissolved (0.1 part per 100 parts of polymer). Then, using a cylindrical concentrating dryer (manufactured by Hitachi, Ltd.), the hydride was melted from the extruder at a temperature of 270 ° C. and a pressure of 1 kPa or less while removing cyclohexane and other volatile components as a solvent from the solution. The mixture was extruded into a strand, cooled, and pelletized to collect a pellet. The weight average molecular weight (Mw) of the hydrogenated ring-opening copolymer containing no polar group was 35,000, the degree of hydrogenation was 99.9%, and the glass transition temperature (Tg) was 161 ° C.
[0044]
(Reference Example 2) Production of polymer containing modified alicyclic structure
Under a nitrogen atmosphere, 500 parts of dehydrated cyclohexane, 0.82 parts of 1-hexene, 0.15 parts of dibutyl ether, and 0.30 parts of triisobutylaluminum were mixed in a reactor at room temperature, and then kept at 45 ° C. 8-ethylidene-tetracyclo [4.4.0.1^2,5. 1^7,10] -Dodeca-3-ene (hereinafter abbreviated as ETCD) (100 parts) and tungsten hexachloride (0.7% toluene solution) (40 parts) were continuously added over 2 hours to carry out polymerization. 1.06 parts of butyl glycidyl ether and 0.52 parts of isopropyl alcohol were added to the polymerization solution to inactivate the polymerization catalyst and terminate the polymerization reaction.
[0045]
Next, 270 parts of cyclohexane was added to 100 parts of the reaction solution containing the obtained ring-opening polymer, and 5 parts of a nickel-alumina catalyst (manufactured by Nikki Chemical Co., Ltd.) was further added as a hydrogenation catalyst. After heating to a temperature of 200 ° C. while stirring under pressure, the reaction was carried out for 4 hours to obtain a reaction solution containing 20% of a hydrogenated ETCD ring-opening polymer. After removing the hydrogenation catalyst by filtration, an antioxidant (manufactured by Ciba Specialty Chemicals; Irganox 1010) was added to the resulting solution and dissolved (0.1 part per 100 parts of polymer). Then, using a cylindrical concentrating dryer (manufactured by Hitachi, Ltd.), the hydride was melted from the extruder at a temperature of 270 ° C. and a pressure of 1 kPa or less while removing cyclohexane and other volatile components as a solvent from the solution. The mixture was extruded into a strand, cooled, and pelletized to collect a pellet. The hydrogenated ring-opened polymer had a weight average molecular weight (Mw) of 40,000, a hydrogenation rate of 99.9%, and a Tg of 138 ° C.
[0046]
Then, 10 parts of maleic anhydride, 3 parts of dicumyl peroxide, and 230 parts of tert-butylbenzene were mixed with 100 parts of the hydrogenated ETCD ring-opening polymer obtained above, and were mixed at 135 ° C. in an autoclave. After performing the reaction for 6 hours, the mixture was poured into a large amount of isopropyl alcohol to cause precipitation, and was collected by filtration. The recovered resin was dried at 100 ° C. and 1 Torr or less for 48 hours to obtain 105 parts by weight of a maleic anhydride-modified polymer. The physical properties of the modified polymer obtained were as follows: a weight average molecular weight (Mw) of 75,600, a glass transition temperature (Tg) of 135 ° C., and a modification ratio of maleic anhydride in the modified polymer.¹It was 0.5 mmol / g as measured by 1 H-NMR.
[0047]
(Reference Example 3) Organophilic treatment of layered crystal compound
A montmorillonite dispersion was obtained by uniformly dispersing 100 parts of layered silicate montmorillonite (major axis: 0.5 μm) in 1000 parts of distilled water at 60 ° C. Next, a solution in which distearyl dimethyl ammonium chloride (20 parts) was dissolved in distilled water (300 parts) was slowly added to the montmorillonite dispersion while stirring the dispersion, followed by stirring at 60 ° C. for 3 hours. The solid was removed by filtration. The obtained solid was added to 500 parts of distilled water at 60 ° C. and redispersed, and then the solid was taken out again by filtration. After repeating the operations of redispersion and filtration three times, water was removed by a freeze-drying method to obtain organophilic montmorillonite.
[0048]
(Example 1)
70 parts of the alicyclic structure-containing polymer containing no polar group obtained in Reference Example 1, 25 parts of the alicyclic structure-containing polymer containing a polar group obtained in Reference Example 2, and obtained in Reference Example 3. Using a twin screw extruder (trade name “TEM-35B”, manufactured by Toshiba Machine Co., Ltd.), melt-knead 5 parts of the obtained organophilic montmorillonite under a nitrogen stream at a barrel temperature of 280 ° C. and pellet again. It has become.
After the pellets obtained above were dried at 70 ° C. for 2 hours using a hot-air dryer through which air was passed, the pellets were extruded into a single-screw extruder having a screw (manufactured by Nippon Steel Works; cylinder inner diameter was 50 mm, Using a screw hoop L / D = 28), a substrate (200 μm thick) was melt-extruded from a coat hanger type T die having a width of 650 mm at a molten resin temperature of 280 ° C. On one surface of the obtained substrate, an ITO (indium tin oxide) film having a thickness of 0.16 μm was formed at 40 ° C. by an ion plating method to prepare a liquid crystal substrate. The thickness of the obtained liquid crystal substrate is 200 μm, and the coefficient of linear expansion in the direction parallel to the surface of the substrate is 4.2 × 10^-5/ ° C, the total light transmittance was 90%.
[0049]
Next, a transparent electrode was patterned on the liquid crystal substrate by photolithography to form a transparent electrode pattern. Then, after forming an alignment film on the transparent electrode pattern by printing, an alignment process was performed by rotary rubbing using a rayon cloth so as to realize a 250 ° twist STN mode liquid crystal. A counter substrate was prepared in the same manner.
[0050]
An ultraviolet-curable sealing resin containing glass fiber mixed at 1.0% by weight was prepared, and this ultraviolet-curable sealing resin was printed on the periphery of one substrate. On the other substrate, resin beads having a predetermined diameter were 200 / mm.²Sprayed at the rate of Then, both substrates were attached to each other, and the sealing resin was cured by ultraviolet irradiation. Thereafter, a mixed liquid crystal obtained by mixing a predetermined amount of a chiral agent into an ester nematic liquid crystal with n = 0.14 is vacuum-injected, sealed with an ultraviolet curable resin, cured by ultraviolet irradiation, and then heat-treated to form a liquid crystal cell. I let it. Next, a liquid crystal display device as shown in FIG. 1 was prototyped, and it was visually confirmed whether or not there was a pixel shift in the liquid crystal display. When the liquid crystal display was confirmed, no pixel shift was observed, and the display state of the liquid crystal was good.
[0051]
(Comparative Example 1)
A pellet was prepared in the same manner as in Example 1 except that the organized montmorillonite obtained in Reference Example 3 was not added, and a liquid crystal substrate was prepared using the pellet. The thickness of this liquid crystal substrate is 0.2 mm, and the coefficient of linear expansion in a direction parallel to the surface of the substrate is 6 × 10^-5/ ° C, the total light transmittance was 92%. Then, a liquid crystal substrate and a liquid crystal display element were formed using this substrate, and the liquid crystal display state was confirmed. As a result, many pixel shifts were observed.
[0052]
The following can be seen from the above Examples and Comparative Examples. According to the present invention, as shown in the examples, a liquid crystal substrate containing an alicyclic structure-containing polymer resin and a layered crystal compound has a linear expansion coefficient of 5 × 10^-5By using a liquid crystal substrate having a total light transmittance of 87% or more at a temperature of / ° C. or less and a thickness of 0.5 mm, it is possible to eliminate pixel shift of a liquid crystal display element using this liquid crystal substrate. On the other hand, in the comparative example, since the coefficient of linear expansion in the direction parallel to the surface of the liquid crystal substrate is large, when this liquid crystal substrate is used, a pixel shift occurs.
[0053]
【The invention's effect】
The liquid crystal substrate of the present invention has a small coefficient of linear expansion in a direction parallel to its surface and a large total light transmittance, so that it is possible to reduce the weight and thickness, and to realize a high-definition liquid crystal display without pixel shift. A liquid crystal display element can be provided.
[Brief description of the drawings]
FIG. 1 is a schematic diagram illustrating an example of a layer configuration of a liquid crystal display element of the present invention.
[Explanation of symbols]
1: Liquid crystal display element
2: Liquid crystal cell
21: Liquid crystal substrate
22: transparent conductive film
23: Alignment film
24: liquid crystal
25: Spacer
26: Sealing material
17: Reflector
31: Upper polarizing plate
32: Lower polarizing plate

Claims (5)

A liquid crystal substrate comprising an alicyclic structure-containing polymer resin and a layered crystal compound, wherein the liquid crystal substrate satisfies the following requirements [1] and [2].
[1] The coefficient of linear expansion in a direction parallel to the surface of the substrate is 5 × 10 ⁻⁵ / ° C. or less.
[2] The total light transmittance at a thickness of 0.5 mm is 87% or more. 2. The liquid crystal substrate according to claim 1, wherein the alicyclic structure-containing polymer resin contains a polar group. The liquid crystal substrate according to claim 2, wherein the content of the polar group in the alicyclic structure-containing polymer resin is 0.01 mmol / g or more. 2. The liquid crystal substrate according to claim 1, wherein the layered crystal compound has been subjected to an organophilic treatment. A liquid crystal display device comprising the liquid crystal substrate according to claim 1.

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