JP2008107562A - Spacer particle dispersion liquid and liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a spacer particle dispersion liquid in which the deterioration in yield can be prevented by nonuniformity of the height of spacer particles and a liquid crystal display device having excellent display quality can be manufactured in a process of manufacturing the liquid crystal display device, and to provide a liquid crystal display device using the spacer dispersion liquid. <P>SOLUTION: The spacer particle dispersion liquid contains spacer particles, an adhesive and a solvent and is used in arranging the spacer particles in an arbitrary position where a resin film of the liquid crystal display device by using an ink jet device is formed, in which the cured matter of the adhesive is harder than the spacer particles. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention provides a spacer particle capable of preventing a decrease in yield due to non-uniform height of spacer particles in a manufacturing process of a liquid crystal display device and manufacturing a liquid crystal display device having excellent display quality. The present invention relates to a dispersion and a liquid crystal display device using the spacer dispersion.

Liquid crystal display devices are currently widely used in personal computers, portable electronic devices, and the like. FIG. 1 is a cross-sectional view illustrating an example of a liquid crystal display device. As shown in FIG. 1, in general, a liquid crystal display device has two transparent substrates in which a transparent electrode 3, an alignment film 8, a color filter 4, a black matrix 5 and the like are arranged on the inner side and a polarizing plate 2 is arranged on the outer side. 1 is arranged so as to face each other with a sealant 9 disposed around them, and the liquid crystal 6 is sealed in the formed gap. In this liquid crystal display device, the spacer particles 7 are used for the purpose of regulating the distance between the two transparent substrates 1 and maintaining an appropriate thickness (cell gap) of the liquid crystal layer.

As a method of disposing such spacer particles on a substrate having a resin film of a liquid crystal display device, for example, in Patent Document 1, a droplet of spacer particle dispersion liquid containing spacer particles is discharged using an ink jet device. A method is disclosed in which spacer particles are placed on a substrate by landing on a predetermined position on the substrate and then drying. According to this method, the spacer particles can be arranged at an arbitrary position on the substrate.

However, in the liquid crystal display device in which the spacer particles are arranged on the substrate by such a method, the spacer particles move due to an external pressure such as vibration applied after the spacer particles are arranged, and the liquid crystal display to be manufactured is not arranged at a predetermined position. There is a problem that unevenness occurs in the cell gap of the apparatus, resulting in uneven display and light leakage.

In order to solve such a problem, for example, Patent Documents 2 and 3 disclose methods for improving the adhesion of spacer particles to a substrate by blending an adhesive into the spacer particle dispersion. FIG. 10 schematically shows a state in which the spacer particles are fixed to the substrate with an adhesive by such a method. As shown in FIG. 10, a plurality of spacer particles 7 are formed on the substrate 1 (alignment film 8). The adhesive cured product 14 is formed so as to cover the lower half of the spacer particles 7.
However, when a liquid crystal display device is manufactured using a spacer particle dispersion containing such an adhesive, an external force is applied to the spacer particles after the spacer particles are fixed to the resin film on the substrate with the cured adhesive. In some cases, the height of the spacer particles becomes non-uniform, and the yield may be reduced. In addition, when a partial pressure is applied to the manufactured liquid crystal display device, the height of the spacer particles becomes uneven and the display quality is improved in a liquid crystal cell configured by arranging a pair of substrates to face each other with spacer particles interposed therebetween. There was a decline.
JP-A-57-58124 JP-A-9-105946 JP 2001-83524 A

In view of the above situation, the present invention manufactures a liquid crystal display device that can prevent a decrease in yield due to non-uniform height of spacer particles in the manufacturing process of the liquid crystal display device and that is excellent in display quality. Another object is to provide a spacer particle dispersion that can be used, and a liquid crystal display device using the spacer dispersion.

The present invention includes spacer particles, an adhesive, and a solvent, and spacer particle dispersion used when the spacer particles are arranged at an arbitrary position on a substrate on which a resin film of a liquid crystal display device is formed using an inkjet device. It is a liquid, and the cured product after curing of the adhesive is a spacer particle dispersion liquid that is harder than the spacer particles.
The present invention will be described in detail below.

As a result of intensive studies, the inventors of the present invention, in the liquid crystal display device in which the spacer particles are fixed on the substrate with a conventional adhesive, the cured product of the adhesive did not have sufficient hardness compared to the spacer particles, It has been found that, when an external force is partially applied to a liquid crystal cell in which a transparent substrate is disposed oppositely across a spacer particle of the liquid crystal display device under an operating temperature environment of the liquid crystal display device, only the spacer particle moves.
That is, FIG. 11 shows a schematic diagram showing a state when an external force is applied to a liquid crystal cell of a conventional liquid crystal display device. As shown in FIG. 11, a resin film 8 is usually formed on the substrate 1. The spacer particles 7 arranged on the resin film 8 are fixed by an adhesive cured product 14. However, the conventional cured adhesive 14 is softer than the spacer particles 7, and when an external force is applied to the spacer particles 7 in such a state, only the spacer particles 7 are pushed into the resin film 8. At this time, since the spacer particles 7 are in point contact with the resin film 8 at the bottom surface, the alignment film 8 deformed by the spacer particles 7 is plastically deformed without being able to disperse the stress. End up. As a result, even after the external force is removed, the once deformed resin film 8 is not restored to its original shape, and the position of the spacer particles 7 does not return to the state before the external force is applied, and the cell gap of the liquid crystal cell Is considered to be uneven.
Therefore, as a result of further intensive studies, the present inventors have determined that an adhesive that fixes the spacer particles to the resin film formed on the substrate surface is harder than the spacer particles in the use temperature environment of the liquid crystal display device. By making it hard, when external force is applied to the liquid crystal cell, the spacer particles and the cured product of the adhesive move together, and the resin film is in surface contact with the entire bottom surface of the cured adhesive product. Therefore, it has been found that plastic deformation can be prevented and unevenness in the cell gap of the liquid crystal cell can be prevented, and the present invention has been completed.
The resin film on which the spacer particles are disposed is a resin film disposed on the substrate of the liquid crystal display element, and is, for example, a black matrix, an RGB portion, an overcoat layer, an alignment film, or the like.

The spacer particle dispersion of the present invention contains spacer particles, an adhesive and a solvent.
Such a spacer particle dispersion of the present invention is used when the spacer particles are disposed at an arbitrary position on a substrate on which a resin film of a liquid crystal display device is formed using an ink jet device. In the agent, the cured product after curing is harder than the spacer particles.
In the present specification, the state that “the cured product after curing of the adhesive is harder than the spacer particles” may be satisfied at least under the normal use temperature condition of the liquid crystal display device.

According to such a spacer particle dispersion of the present invention, the spacer particles arranged on the substrate on which the resin film is formed are fixed with the cured product after curing of the adhesive, and another substrate is attached via the spacer particles. Even when an external force is applied to the liquid crystal cell formed together, the cell gap of the liquid crystal cell can be accurately maintained.
FIG. 9 is a schematic view showing a state when an external force is applied to the liquid crystal cell using the spacer particle dispersion of the present invention.
As shown in FIG. 9, a resin film 8 is usually formed on the substrate 1, and the spacer particles 7 arranged on the resin film 8 are fixed by an adhesive cured product 15. When an external force is applied to the spacer particles 7 in the liquid crystal cell in such a state, the cured adhesive 15 is harder than the spacer particles 7, so that an integrated product of the spacer particles 7 and the cured adhesive 15 is applied to the resin film 8. Pushed in. At this time, since the integrated product of the spacer particles 7 and the cured adhesive 15 is in surface contact with the resin film 8, the stress applied to the resin film 8 by the integrated product is dispersed and deformed resin. The film 8 is elastically recovered after the external force is removed and restored to the original shape, and the position of the spacer particles 7 also returns to the state before the external force is applied.

The spacer particle dispersion of the present invention contains an adhesive.
In the liquid crystal display device manufactured using the spacer particle dispersion liquid of the present invention, the adhesive serves to bond and fix the spacer particles arranged on the substrate on which the resin film is formed to the substrate. It is.
In the spacer particle dispersion of the present invention, the cured product is a cured product that is harder than the spacer particles. As a raw material for such an adhesive, for example, a material whose compressive elastic modulus (10% K value) when the cured product is displaced by 10% is larger than 10% K value of spacer particles described later. Select as appropriate.

Moreover, as said adhesive agent, it is preferable that the glass transition temperature (Tg) of the hardened | cured material after hardening is 80 degreeC or more. When the temperature is lower than 80 ° C., when an external force is applied when the liquid crystal display device using the spacer particle dispersion of the present invention is used, the cell gap of the liquid crystal cell may become non-uniform and the display quality may deteriorate. A spacer particle dispersion containing an adhesive having such a cured product having a glass transition temperature (Tg) of 80 ° C. or higher is also one aspect of the present invention.

Such an adhesive is not particularly limited. For example, (meth) acrylic acid, vinylpyrrolidone, methyl (meth) acrylate, styrene, 4-biphenyl (meth) acrylate, pentachlorophenyl (meth) acrylate, 2-cyanobutyl ( (Meth) acrylate, 2-cyanophenyl (meth) acrylate, cyanomethyl (meth) acrylate, 4-cyanophenyl (meth) acrylate, ferrocenylethyl (meth) acrylate, ferrocenylmethyl (meth) acrylate, 3,5- Dimethyladamantyl (meth) acrylate, naphthyl (meth) acrylate, N-sec-butyl (meth) acrylamide, N-tert-butyl (meth) acrylamide, N-isopropyl (meth) acrylamide, N, N-diisopropyl (me ) Acrylamide, N, N-dimethyl (meth) acrylamide, N- (1-methylbutyl) (meth) acrylamide, N-methyl-N-phenyl (meth) acrylamide, morpholyl (meth) acrylamide, piperidyl (meth) acrylamide, adamantyl (Meth) acrylate, tert-butyl (meth) acrylate, chloroethyl (meth) acrylate, cyanoethyl (meth) acrylate, cyanomethylphenyl (meth) acrylate, cyanophenyl (meth) acrylate, cyclohexyl (meth) acrylate, 4-tert- Butylcyclohexyl (meth) acrylate, hydroxyethyl (meth) acrylate, isobornyl (meth) acrylate, isopropyl (meth) acrylate, 4-methoxycarbonyl Nyl (meth) acrylate, 3,3-dimethyl-2-butyl (meth) acrylate, trimethylsilyl (meth) acrylate, phenyl (meth) acrylate, 4-tert-butylphenyl (meth) acrylate, 4-butoxycarbonylphenyl (meth) ) Acrylamide, 4-carboxyphenyl (meth) acrylamide, 4-ethoxycarbonylphenyl (meth) acrylamide, 4-methoxycarbonylphenyl (meth) acrylamide, butyl cyano (meth) acrylate, cyclohexyl chloro (meth) acrylate, ethyl chloro (meth) acrylate , Isobutylchloro (meth) acrylate, isopropylchloro (meth) acrylate, 1-methoxycarbonyl-1-methoxycarbonylmethyleneethylene, methylchloro (Meth) acrylate, methylfluoro (meth) acrylate, methylphenyl (meth) acrylate, maleic anhydride, maleic acid, monoalkyl and dialkyl esters of maleic acid; fumaric acid, monoalkyl and dialkyl esters of fumaric acid; maleimide , Maleimide derivatives such as methylmaleimide, ethylmaleimide, propylmaleimide, butylmaleimide, octylmaleimide, dodecylmaleimide, stearylmaleimide, phenylmaleimide, cyclohexylmaleimide; nitrile group-containing vinyl monomers such as (meth) acrylonitrile; ) Amide group-containing vinyl monomers such as acrylamide, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate (meth) acrylic acid alkyl esters such as n-octyl (meth) acrylate, dodecyl (meth) acrylate and stearyl (meth) acrylate; (meth) acrylic acid aryl esters such as benzyl (meth) acrylate; Contains (meth) acrylic acid substituents such as hydroxyethyl (meth) acrylic acid, hydroxypropyl (meth) acrylate, glycidyl (meth) acrylate, 2-aminoethyl (meth) acrylate, and γ- (methacryloyloxypropyl) trimethoxysilane Alkyl esters; (meth) acrylic acid derivatives such as adducts of methoxyethyl (meth) acrylate and ethylene oxide (meth) acrylate; trifluoromethylmethyl (meth) acrylate, 2-trifluoromethylethyl (meth) acrylate (Meth) acrylic acid perfluoroalkyl esters such as relate, 2-perfluoroethylethyl (meth) acrylate, 2-perfluoroethyl-2-perfluorobutylethyl (meth) acrylate, 2-perfluoroethyl (meth) acrylate (Meth) acrylic acid monomer; aromatic vinyl monomers such as vinyltoluene, α-methylstyrene, chlorostyrene, styrenesulfonic acid and its sodium salt; perfluoromethyl (meth) acrylate, diper Fluoromethylmethyl (meth) acrylate, 2-perfluoromethyl-2-perfluoroethylmethyl (meth) acrylate, triperfluoromethylmethyl (meth) acrylate, 2-perfluorohexylethyl (meth) acrylate, 2-perfluoro Decylethyl Fluorine-containing vinyl monomers such as (meth) acrylate, 2-perfluorohexadecylethyl (meth) acrylate, perfluoroethylene, perfluoropropylene, vinylidene fluoride; vinyltrimethoxysilane, vinyltriethoxysilane, γ- ( Silicon-containing vinyl monomers such as methacryloyloxypropyl) trimethoxysilane; vinyl esters such as vinyl acetate, vinyl propionate, vinyl pivalate, vinyl benzoate and vinyl cinnamate; alkenes such as ethylene and propylene; Examples include dienes such as butadiene and isoprene; polymers or copolymers of monomers such as vinyl chloride, vinylidene chloride, allyl chloride, and allyl alcohol. These monomers may be used independently and 2 or more types may be used together.

As the adhesive, it is preferable to appropriately polymerize the above-mentioned monomers so that the polymer is harder than the spacer particles, and those having a Tg of 80 ° C. or higher are suitably used.
The adhesive having a Tg of 80 ° C. or higher is not particularly limited. For example, (meth) acrylic acid, vinyl pyrrolidone, methyl (meth) acrylate, styrene, 4-biphenyl (meth) acrylate, pentachlorophenyl (meta ) Acrylate, 2-cyanobutyl (meth) acrylate, 2-cyanophenyl (meth) acrylate, cyanomethyl (meth) acrylate, 4-cyanophenyl (meth) acrylate, ferrocenylethyl (meth) acrylate, ferrocenylmethyl (meta) ) Acrylate, 3,5-dimethyladamantyl (meth) acrylate, naphthyl (meth) acrylate, N-sec-butyl (meth) acrylamide, N-tert-butyl (meth) acrylamide, N-isopropyl (meth) acrylamide, N, N Diisopropyl (meth) acrylamide, N, N-dimethyl (meth) acrylamide, N- (1-methylbutyl) (meth) acrylamide, N-methyl-N-phenyl (meth) acrylamide, morpholyl (meth) acrylamide, piperidyl (meth) Acrylamide, adamantyl (meth) acrylate, tert-butyl (meth) acrylate, chloroethyl (meth) acrylate, cyanoethyl (meth) acrylate, cyanomethylphenyl (meth) acrylate, cyanophenyl (meth) acrylate, cyclohexyl (meth) acrylate, 4 -Tert-butylcyclohexyl (meth) acrylate, hydroxyethyl (meth) acrylate, isobornyl (meth) acrylate, isopropyl (meth) acrylate, 4- Toxicarbonylphenyl (meth) acrylate, 3,3-dimethyl-2-butyl (meth) acrylate, trimethylsilyl (meth) acrylate, phenyl (meth) acrylate, 4-tert-butylphenyl (meth) acrylate, 4-butoxycarbonylphenyl (Meth) acrylamide, 4-carboxyphenyl (meth) acrylamide, 4-ethoxycarbonylphenyl (meth) acrylamide, 4-methoxycarbonylphenyl (meth) acrylamide, butyl cyano (meth) acrylate, cyclohexyl chloro (meth) acrylate, ethyl chloro (meta ) Acrylate, isobutylchloro (meth) acrylate, isopropylchloro (meth) acrylate, 1-methoxycarbonyl-1-methoxycarbonylmethylene Tylene, methylchloro (meth) acrylate, methylfluoro (meth) acrylate, methylphenyl (meth) acrylate, maleic anhydride, maleic acid, monoalkyl esters and dialkyl esters of maleic acid; fumaric acid, monoalkyl esters of fumaric acid and Dialkyl esters; maleimide derivatives such as maleimide, methylmaleimide, ethylmaleimide, propylmaleimide, butylmaleimide, octylmaleimide, dodecylmaleimide, stearylmaleimide, phenylmaleimide, cyclohexylmaleimide; nitrile group-containing vinyl monomers such as (meth) acrylonitrile Polymers or copolymers obtained by polymerizing monomers (hereinafter also referred to as main monomers) such as amide group-containing vinyl monomers such as (meth) acrylamide Preferably it contains the body. These main monomers may be used independently and 2 or more types may be used together.

When the Tg of the cured product of the adhesive is 80 ° C., the blending amount of the main monomer and the like in the raw material monomer in the polymer is not particularly limited as long as the Tg can be 80 ° C. or more. A preferred lower limit is 50% by weight. If it is less than 50% by weight, the Tg of the adhesive may not be 80 ° C. or higher. A more preferred lower limit is 60% by weight.

Furthermore, since the said copolymer can reduce the contamination with respect to a liquid crystal, it is preferable to have a crosslinked structure. Examples of a method for introducing a crosslinked structure into the copolymer include a method of containing a monomer that causes a crosslinking reaction as a raw material monomer.
Examples of the monomer that causes the crosslinking reaction include 2-hydroxyethyl (meth) acrylate, 1,4-hydroxybutyl (meth) acrylate, (poly) caprolactone-modified hydroxyethyl (meth) acrylate, allyl alcohol, and glycerin monoallyl ether. , Vinyl monomers having a hydroxyl group such as glycerol (meth) acrylate; acrylic acid such as (meth) acrylic acid, α-ethylacrylic acid, crotonic acid, itaconic acid, carboxyethyl acrylate, and α-alkyl derivatives thereof; β-alkyl derivatives, glycidyl (meth) acrylate, glycidyl α-ethyl (meth) acrylate, glycidyl α-n-butyl (meth) acrylate, (meth) acrylic acid-3,4-epoxybutyl, (meth) Acrylic acid-6,7-epoxy Examples thereof include monomers having an epoxy group such as glycidyl (meth) acrylate such as butyl and α-ethyl (meth) acrylic acid-6,7-epoxyheptyl. These may be used independently and 2 or more types may be used together.

The molecular weight of such a copolymer is not particularly limited, but the preferred lower limit is 2000 and the preferred upper limit is 400,000 in terms of weight average molecular weight measured by GPC (gel permeation chromatography). If it is less than 2000, it is difficult to increase Tg, and there are many molecules that are not crosslinked even after the crosslinking reaction, which contaminates the liquid crystal. If it exceeds 400,000, thixotropy appears in the solution, and the ink jet head cannot stably discharge. A more preferable lower limit is 5000, and a more preferable upper limit is 200,000.

The adhesive may contain other adhesive components other than the copolymer, and the other adhesive components are not particularly limited. For example, polyvinyl alcohol, modified products thereof, polyethyleneimine, cellulose modified products Hydrophilic polymers such as polysaccharides such as are preferably used.

Moreover, the said adhesive agent may contain the polyfunctional compound as a crosslinking agent which raise | generates a crosslinking reaction. Such polyfunctional compounds are not particularly limited, and examples thereof include polyvalent amino compounds, polyvalent aziridine compounds, polyvalent epoxy compounds, and polyvalent carboxylic acid (anhydride) compounds.

In the spacer particle dispersion of the present invention, the content of the adhesive is not particularly limited, but a preferable lower limit is 10 parts by weight and a preferable upper limit is 500 parts by weight with respect to 100 parts by weight of spacer particles described later. When the amount is less than 10 parts by weight, in the liquid crystal display device using the spacer particle dispersion of the present invention, the adhesion between the spacer particles and the substrate on which the alignment film is formed may be insufficient. If it exceeds, the adhesive may elute in the liquid crystal of the liquid crystal display device using the spacer particle dispersion of the present invention to cause liquid crystal contamination. A more preferred lower limit is 20 parts by weight, and a more preferred upper limit is 300 parts by weight.

The spacer particle dispersion of the present invention contains spacer particles.
The spacer particles are used for the purpose of regulating the distance between two substrates of a liquid crystal display device manufactured using the spacer particle dispersion of the present invention and maintaining an appropriate thickness (cell gap) of the liquid crystal layer. is there.

The spacer particles are not particularly limited, and may be inorganic particles such as silica particles or organic particles such as organic polymers. Among these, organic particles are preferable because they have an advantage of easily following a change in thickness due to thermal expansion and contraction.

Although it does not specifically limit as said organic type particle | grain, Usually, since intensity | strength etc. exist in the suitable range, the copolymer of a monofunctional monomer and a polyfunctional monomer is used preferably. In this case, the ratio of the monofunctional monomer to the polyfunctional monomer is not particularly limited, and is appropriately adjusted depending on the strength and hardness required for the obtained organic particles.

Examples of the monofunctional monomer include styrene derivatives such as styrene, α-methylstyrene, p-methylstyrene, p-chlorostyrene, and chloromethylstyrene; vinyl chlorides; vinyl esters such as vinyl acetate and vinyl propionate. Unsaturated nitriles such as acrylonitrile; methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, stearyl (meth) acrylate, ethylene glycol (meth) ) Acrylate, trifluoroethyl (meth) acrylate, pentafluoropropyl (meth) acrylate, (meth) acrylic acid ester derivatives such as cyclohexyl (meth) acrylate, and the like. These monofunctional monomers may be used alone or in combination of two or more. In the present specification, (meth) acryl means acryl and methacryl.

Examples of the polyfunctional monomer include divinylbenzene, 1,6-hexanediol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, tetramethylolmethanetri (meth) acrylate, tetramethylolpropanetetra (meta ) Acrylate, diallyl phthalate and its isomer, triallyl isocyanurate and its derivative, trimethylolpropane tri (meth) acrylate and its derivative, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (Meth) acrylate, polyethylene glycol di (meth) acrylate such as ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, etc. Ripropylene glycol di (meth) acrylate, polytetramethylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, 1,3-butylene glycol di (meth) acrylate, 2,2-bis [4- (methacrylic) 2,2-bis [4- (methacryloxypolyethoxy) phenyl] propane di (meth) acrylate such as loxyethoxy) phenyl] propanedi (meth) acrylate, 2,2-hydrogenated bis [4- (acryloxypolyethoxy) Phenyl] propane di (meth) acrylate, 2,2-bis [4- (acryloxyethoxypolypropoxy) phenyl] propane di (meth) acrylate, and the like. These polyfunctional monomers may be used independently and 2 or more types may be used together.

In addition, as the monofunctional or polyfunctional monomer, a monomer having a hydrophilic group may be used in order to improve dispersibility in a solvent described later. Examples of the hydrophilic group include a hydroxyl group, a carboxyl group, a sulfonyl group, a phosphonyl group, an amino group, an amide group, an ether group, a thiol group, and a thioether group.

As monomers having such a hydrophilic group, 2-hydroxyethyl (meth) acrylate, 1,4-hydroxybutyl (meth) acrylate, (poly) caprolactone-modified hydroxyethyl (meth) acrylate, allyl alcohol, glycerin Monomers having a hydroxyl group such as monoallyl ether; acrylic acids such as (meth) acrylic acid, α-ethylacrylic acid and crotonic acid, and α- or β-alkyl derivatives thereof; fumaric acid, maleic acid, citracone Unsaturated dicarboxylic acids such as acids and itaconic acids; monomers having a carboxyl group such as mono 2- (meth) acryloyloxyethyl ester derivatives of these unsaturated dicarboxylic acids; t-butylacrylamidesulfonic acid, styrenesulfonic acid, 2 -Acrylamide-2-methylpropanesulfonic acid, etc. Monomers having a sulfonyl group; Monomers having a phosphonyl group such as vinyl phosphate and 2- (meth) acryloyloxyethyl phosphate; Amino groups such as amines having an acryloyl group such as dimethylaminoethyl methacrylate and diethylaminoethyl methacrylate A compound having both a hydroxyl group and an ether group such as (poly) ethylene glycol (meth) acrylate and (poly) propylene glycol (meth) acrylate; a terminal alkyl ether of (poly) ethylene glycol (meth) acrylate , Monomers having an ether group such as (poly) propylene glycol (meth) acrylate terminal alkyl ether, tetrahydrofurfuryl (meth) acrylate, etc .; (meth) acrylamide, methylol (meth) acrylate Amides, monomer having a amide group such as vinyl pyrrolidone.

The method for producing particles by polymerizing the monomer is not particularly limited, and examples thereof include various polymerization methods such as a suspension polymerization method, a seed polymerization method, and a dispersion polymerization method.

In the suspension polymerization method, since the particle size distribution of the obtained particles is relatively wide and polydisperse particles are obtained, when used as spacer particles, classification operation is performed to obtain a desired particle size or particle size distribution. It is suitably used when obtaining various types of particles. On the other hand, seed polymerization and dispersion polymerization can be suitably used when producing a large amount of particles having a specific particle diameter because monodispersed particles can be obtained without going through a classification step.

The suspension polymerization method is a method in which a monomer composition comprising a monomer and a polymerization initiator is dispersed and polymerized in a poor solvent so as to have a target particle size. As the dispersion medium used for the suspension polymerization, a solution obtained by adding a dispersion stabilizer to water is usually used. Examples of the dispersion stabilizer include polymers soluble in the medium, such as polyvinyl alcohol, polyvinyl pyrrolidone, methyl cellulose, ethyl cellulose, polyacrylic acid, polyacrylamide, and polyethylene oxide. Nonionic or ionic surfactants are also used as appropriate. The polymerization conditions vary depending on the polymerization initiator and the type of monomer, but the polymerization temperature is usually 50 to 80 ° C. and the polymerization time is 3 to 24 hours.

The seed polymerization method is a polymerization method in which a monodispersed seed particle synthesized by soap-free polymerization or emulsion polymerization is further expanded to a target particle size by further absorbing a monomer. The organic monomer used for the seed particles is not particularly limited, and the above-mentioned monomers are used. The composition of the seed particles is a monomer for seed polymerization in order to suppress phase separation during seed polymerization. A monomer having an affinity for the component is preferred, and styrene and its derivatives are preferred from the viewpoint of monodispersity of the particle system distribution.

Since the particle size distribution of the seed particles is also reflected in the particle size distribution after seed polymerization, it is preferably monodispersed as much as possible, and the Cv value is preferably 5% or less. As described above, phase separation from the seed particles is likely to occur during seed polymerization. Therefore, the monomer absorbed during seed polymerization is preferably as close to the seed particle composition as possible. If the seed particles are styrene, aromatic divinyl is used. In the case of a monomer or acrylic, it is preferable to polymerize by absorbing an acrylic polyfunctional vinyl monomer.

In the seed polymerization method, a dispersion stabilizer can be used as necessary. The dispersion stabilizer is not particularly limited as long as it is a polymer soluble in the medium, and examples thereof include polyvinyl alcohol, polyvinyl pyrrolidone, methyl cellulose, ethyl cellulose, polyacrylic acid, polyacrylamide, and polyethylene oxide. Nonionic or ionic surfactants are also used as appropriate.

In the seed polymerization method, it is preferable to add 20 to 100 parts by weight of the monomer with respect to 1 part by weight of the seed particles.

The medium used for the seed polymerization is not particularly limited and should be appropriately determined depending on the monomer used. Generally, suitable organic solvents include alcohols, cellosolves, ketones or hydrocarbons. Furthermore, these can be used alone or as a mixed solvent with other organic solvents, water, etc. which are compatible with each other. Specifically, for example, acetonitrile, N, N-dimethylformamide, dimethyl sulfoxide, alcohols such as ethyl acetate, methanol, ethanol and propanol, cellosolves such as methyl cellosolve and ethyl cellosolve, acetone, methyl ethyl ketone and methyl butyl ketone And ketones such as 2-butanone.

The above dispersion polymerization method is a polymerization in a poor solvent system in which the monomer is dissolved but the generated polymer is not dissolved, and the resulting polymer is precipitated in a particle shape by adding a polymer dispersion stabilizer to this system. It is a method to make it.

In general, when the cross-linking component is polymerized by dispersion polymerization, the particles tend to aggregate and it is difficult to stably obtain monodisperse cross-linked particles. However, by selecting the conditions, the monomer containing the cross-linking component is polymerized. It becomes possible to do.

In the polymerization, a polymerization initiator is used and is not particularly limited. For example, benzoyl peroxide, lauroyl peroxide, orthochlorobenzoyl peroxide, orthomethoxybenzoyl peroxide, 3,5,5-trimethylhexanoyl peroxide, Organic peroxides such as t-butylperoxy-2-ethylhexanoate and di-t-butylperoxide, azobisisobutyronitrile, azobiscyclohexacarbonitrile, azobis (2,4-dimethylvaleronitrile) An azo compound such as) is preferably used. In general, the amount of the polymerization initiator used is preferably in the range of 0.1 to 10 parts by weight with respect to 100 parts by weight of the monomer used in the polymerization.

The spacer particles may be subjected to a surface treatment. By performing the surface treatment, it is possible to improve the monodispersibility of the spacer particles in a solvent, which will be described later, and to prevent the generation of aggregated particles. This is because it can be stably discharged onto the substrate on which the alignment film of the liquid crystal display device is formed using the device, and it becomes easy to accurately control the cell gap of the liquid crystal display device to be manufactured.

Examples of the surface treatment of the spacer particles include a method of modifying the surface of the spacer particles. Specifically, as disclosed in JP-A-1-247154, a resin is deposited on the surface of the spacer particles. And a method of modifying by acting a compound that reacts with a functional group on the surface of the spacer particles as disclosed in JP-A-9-1193915 and JP-A-7-300587, No. 223821, JP-A 2003-295198, a method of performing surface modification by graft polymerization on the surface of spacer particles, Japanese Patent Application No. 2005-354832, Japanese Patent Application No. 2005-354831, Japanese Patent Application No. 2005-239162. A method for surface modification by swelling and adsorbing monomers onto spacer particles as described in No. A method in which a monomer is absorbed in the shell portion of the core-shell particles as described in JP-A-05-34832 and a polymerization method, a method in which a monomer is absorbed into the particle surface by a supercritical method as described in Japanese Patent Application No. 2005-239162, and a polymerization method. As described in Japanese Patent Application No. 2005-354831, a method in which a monomer is adsorbed and polymerized on a compound adsorbed on the particle surface, and other methods described in Japanese Patent Application Nos. 2005-216065 and 2005-180312 are exemplified.

As a method for modifying the surface of the spacer particles, a method of forming a surface layer chemically bonded to the surface of the spacer particles is preferable because there are few problems such as peeling of the surface layer and elution into the liquid crystal in the cell of the liquid crystal display device. Among them, the method described in JP-A No. 11-223820 is a method in which an oxidizing agent is reacted with particles having a reducing group on the surface, radicals are generated on the particle surface, and graft polymerization is performed on the surface. This is preferable because a surface layer having a sufficient thickness can be formed.

In addition, the effect of improving the adhesion of the spacer particles to the substrate by applying such a surface treatment and the alignment of the liquid crystal in the liquid crystal display device are disturbed by appropriately selecting the monomer used for the surface treatment. The effect of disappearing can be imparted to the spacer particles.

The spacer particles may be subjected to a chargeable process. Since the spacer particles are subjected to a chargeable treatment, the surface potential of the spacer particles indicated by zeta potential or the like is reduced in the drying process when manufacturing the liquid crystal display device using the spacer particle dispersion of the present invention. Can be changed. When the zeta potential on the surface of the spacer particles is high, it can be said that the spacer particles are likely to repel each other in the spacer particle dispersion and are less likely to aggregate.
The chargeable treatment means that the spacer particles are treated so as to have some potential even in the spacer particle dispersion of the present invention, and this potential (charge) is determined by an existing method such as a zeta potential measuring device. It can be measured.

Examples of a method for performing chargeable treatment on the spacer particles include, for example, a method of containing a charge control agent in the spacer particles, a method of manufacturing spacer particles from a monomer containing a monomer that is easily charged, and the surface described above. For example, a method of performing a surface treatment capable of charging the spacer particles by using a method of performing the treatment may be used.

The spacer particles may be colored and used for improving the contrast of a liquid crystal display device produced using the spacer particle dispersion of the present invention. Colored spacer particles include, for example, spacer particles treated with carbon black, disperse dyes, acid dyes, basic dyes, metal oxides, etc., and an organic film is formed on the surface of the spacer particles and decomposes at a high temperature. Or the carbonized spacer particle | grains etc. are mentioned. In addition, when the material itself which forms spacer particle | grains has a color, you may use as it is, without coloring.

Although it does not specifically limit as content of such spacer particle | grains, A preferable minimum is 0.05 weight% and a preferable upper limit is 7 weight%. If it is less than 0.05% by weight, it may be difficult to maintain a uniform cell gap of the liquid crystal display device using the spacer particle dispersion of the present invention. When ejecting the spacer particle dispersion of the present invention, the nozzles of the ink jet apparatus are easily clogged, or the content of the spacer particles in the discharged droplets of the spacer particle dispersion of the present invention is excessive. Thus, it may be difficult to move the spacer particles during the drying process of the droplets. A more preferred lower limit is 0.1% by weight, and a more preferred upper limit is 3% by weight.

Further, the particle diameter of the spacer particles is not particularly limited because it can be appropriately selected depending on the type of liquid crystal display device to be produced, but the preferable lower limit is 1 μm and the preferable upper limit is 20 μm. If the thickness is less than 1 μm, the opposing substrates may come into contact with each other and may not function sufficiently as a spacer of a liquid crystal display device. If it exceeds 20 μm, when spacer particles are arranged in a specific position such as a non-pixel region on the substrate, it is easy to protrude from the non-pixel region and the distance between the opposing substrates becomes large. In some cases, the liquid crystal display device cannot sufficiently meet the demand for downsizing.

Since the spacer particles used in the present invention are used as a gap material for maintaining an appropriate thickness of the liquid crystal layer, a certain strength is required. Appropriateness of the liquid crystal display device manufactured using the spacer particle dispersion of the present invention when expressed as a compressive elastic modulus (10% K value) when the particle diameter is displaced by 10% as an index indicating the compressive strength of the particles In order to maintain the thickness of the liquid crystal layer, the preferable lower limit is 2000 MPa, and the preferable upper limit is 15000 MPa. When the pressure is less than 2000 MPa, the spacer particles are deformed by a press pressure when the liquid crystal display device is manufactured using the spacer particle dispersion of the present invention, and an appropriate gap is hardly generated. When the pressure is higher than 15000 MPa, display abnormality may occur in the liquid crystal display device manufactured by damaging the alignment film on the substrate when the liquid crystal display device is manufactured using the spacer particle dispersion of the present invention.

The compression elastic modulus (10% K value) of the spacer particles is a value determined in accordance with the method described in JP-T-6-503180. For example, using a micro compression tester (PCT-200, manufactured by Shimadzu Corporation), a smooth end surface of a diamond cylinder having a diameter of 50 μm is used to determine the weight for straining spacer particles by 10%.

The spacer particle dispersion of the present invention contains a solvent.
As the solvent for the spacer particle dispersion of the present invention, water or a hydrophilic solvent may be used, or a hydrophobic solvent may be used.

It does not specifically limit as said water, For example, ion-exchange water, pure water, ground water, tap water, industrial water etc. are mentioned. These may be used independently and 2 or more types may be used together.

The hydrophilic organic solvent is not particularly limited, and examples thereof include ethanol, n-propanol, 2-propanol, 1-butanol, 2-butanol, 1-methoxy-2-propanol, furfuryl alcohol, and tetrahydrofurfuryl alcohol. Monoalcohols; ethylene glycol multimers such as ethylene glycol, diethylene glycol, triethylene glycol, tetraethylene glycol; propylene glycol multimers such as propylene glycol, dipropylene glycol, tripropylene glycol, tetrapropylene glycol; ethylene glycol multimers And lower polymers such as monomethyl ether, monoethyl ether, monoisopropyl ether, monopropyl ether, monobutyl ether Alkyl ethers; ethylene glycol multimers and propylene glycol multimers dimethyl ether, diethyl ether, diisopropyl ether, dipropyl ether and other lower dialkyl ethers; ethylene glycol multimers and propylene glycol multimers monoacetate, di Alkyl esters such as acetate; 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 3-methyl-1,5-pentanediol, 3-hexene- 2,5-diol, 1,5-pentanediol, 2,4-pentanediol, 2-methyl-2,4-pentanediol, 2,5-hexanediol, 1,6-hexanediol, neopentyl glycol, etc. Diols; ethers of diols Conductor; acetate derivatives of diols; glycerin, 1,2,4-butanetriol, 1,2,6-hexanetriol, 1,2,5-pentanetriol, trimethylolpropane, trimethylolethane, pentaerythritol, etc. Polyhydric alcohols; ether derivatives of polyhydric alcohols; acetate derivatives of polyhydric alcohols, dimethyl sulfoxide, thiodiglycol, N-methyl-2-pyrrolidone, N-vinyl-2-pyrrolidone, γ-butyrolactone, 1,3-dimethyl-2-imidazolidine, sulfolane, formamide, N, N-dimethylformamide, N, N-diethylformamide, N-methylformamide, acetamide, N-methylacetamide, α-terpineol, ethylene carbonate, propylene carbonate Chromatography, bis -β- hydroxyethyl sulfone, bis -β- hydroxyethyl urea, N, N-diethylethanolamine, Abiechinoru, diacetone alcohol, urea, 2-pyrrolidone, nitrobenzene, and the like. These hydrophilic organic solvents may be used independently and 2 or more types may be used together.
The water and the hydrophilic organic solvent may be used alone or in combination.

The hydrophobic solvent preferably has a surface tension at room temperature of 30 mN / m or more.

In the spacer particle dispersion of the present invention, as the solvent, for example, a low boiling point, low surface tension solvent and a high boiling point, high surface tension solvent are preferably mixed. By selecting such a combination, the surface tension increases as the droplets of the spacer particle dispersion liquid of the present invention landed on the substrate on which the resin film is formed by discharging using an ink jet device is dried. A force that reduces the diameter of the droplet as the droplet dries acts, thereby limiting the range in which the final spacer particles adhere.

Specific examples of the solvent having a low boiling point and a low surface strength include organic solvents having a boiling point of less than 150 ° C. and a surface tension at 20 ° C. of less than 28 mN / m. More preferably, the organic solvent has a boiling point of 70 ° C. or more and less than 100 ° C. and a surface tension at 20 ° C. of less than 28 mN / m. In addition, in this specification, a boiling point means the boiling point on 1 atmosphere conditions.

The organic solvent having a boiling point of less than 150 ° C. and a surface tension at 20 ° C. of less than 28 mN / m is not particularly limited. For example, ethanol, n-propanol, 2-propanol, 1-butanol, 2-butanol, tert-butanol And lower monoalcohols such as acetone and the like. These may be used independently and 2 or more types may be used together. Of these, 2-propanol is most preferable.

The organic solvent having a boiling point of less than 150 ° C. and a surface tension at 20 ° C. of less than 28 mN / m is relatively low when the spacer particle dispersion of the present invention is discharged onto a substrate on which a resin film is formed and then dried. Volatilizes at temperature. In particular, in the spacer particle dispersion of the present invention, if the solvent contacts the resin film at a high temperature, the resin film is contaminated and the display quality of the liquid crystal display device is impaired, so that the drying temperature cannot be made too high. However, if the organic solvent having a boiling point of less than 150 ° C. and a surface tension of less than 28 mN / m at 20 ° C. is likely to volatilize at room temperature, aggregated particles are likely to be generated during the production or storage of the spacer particle dispersion of the present invention. In addition, the spacer particle dispersion of the present invention in the vicinity of the nozzle of the ink jet apparatus is likely to be dried, and the discharge property of the ink jet apparatus is impaired. Therefore, a hydrophilic organic solvent that easily volatilizes at room temperature is not preferable.

In general, the ink jet apparatus exhibits good discharge accuracy when the surface tension of the spacer particle dispersion to be discharged at 20 ° C. is 30 to 50 mN / m. On the other hand, the higher the surface tension of the droplets of the spacer particle dispersion discharged onto the substrate on which the resin film is formed is suitable for moving the spacer particles in the drying process.
When the organic solvent having a low boiling point and a low surface tension has an upper limit of the surface tension at 20 ° C. of 28 mN / m, the surface tension of the spacer particle dispersion of the present invention is relatively low at the time of discharge. It becomes possible to obtain good discharge accuracy, and after being discharged onto the substrate on which the resin film is formed, it is volatilized before other solvent components in the spacer particle dispersion of the present invention, and the spacer of the present invention. Since the surface tension of the particle dispersion increases, the movement of the spacer particles during the drying process is facilitated.

Specific examples of the high boiling point and high surface tension solvent include organic solvents having a boiling point of 150 ° C. or higher and a surface tension at 20 ° C. of 30 mN / m or higher. More preferably, the organic solvent has a boiling point of 150 to 200 ° C. and a surface tension at 20 ° C. of 30 mN / m or more.

The organic solvent having a boiling point of 150 ° C. or higher and a surface tension at 20 ° C. of 30 mN / m or higher is not particularly limited, and examples thereof include ethylene glycol, propylene glycol, 1,3-propanediol, and 1,4-butanediol. Examples include various butanediols. These may be used alone or in combination of two or more. Of these, ethylene glycol is most preferred, followed by propylene glycol and 1,3-propanediol.

Hydrophobic solvents having a boiling point of 150 ° C. or higher and a surface tension at 20 ° C. of 30 mN / m or higher include acetophenone, anitol, anethole, ethyl benzoate, butyl benzoate, propyl benzoate, benzyl benzoate, and methyl benzoate. Dimethyl glutarate, ethyl cinnamate, butyl cinnamate, dimethyl cinnamate, ethyl salicylate, methyl salicylate, diethylene glycol, cyclohexanol, cyclohexanone, cycloheptanone, dimethyl sulfoxide, 1,2-dimethylnaphthalene, triacetin, triacetin Ethylene glycol, ethyl naphthoate, ethyl phenylacetate, phenetol, diethyl phthalate, butyl carbitol acetate, heptaethylene glycol, formamide, dimethyl maleate, dimethyl malonate, buty Carbitol include Texanol and malic acid diethyl.

When the organic solvent having a high boiling point and high surface tension has a boiling point of 150 ° C. or higher, it is possible to prevent the spacer particles from agglomerating by drying during the production or storage of the spacer particle dispersion of the present invention. When the spacer particle dispersion liquid of the present invention is discharged using an ink jet apparatus and the spacer particles are arranged, the spacer particle dispersion liquid of the present invention is excessively dried in the vicinity of the nozzle, and the discharge property and discharge accuracy are impaired. Can be suppressed.

The organic solvent having a high boiling point and a high surface tension has a boiling point from the spacer particle dispersion of the present invention discharged onto the substrate on which the alignment film is formed because the surface tension at 20 ° C. is 30 mN / m or more. Since the surface tension of the spacer particle dispersion of the present invention is kept high after the lower organic solvent is volatilized, the spacer particles can be easily moved during the drying process.

Further, when an organic solvent is used, the spacer particle dispersion of the present invention may contain the solvent X having a boiling point of 200 ° C. or higher and a surface tension at 20 ° C. of 42 mN / m or higher. . By containing such a solvent X, the spacer particle dispersion of the present invention is discharged onto the substrate surface on which the alignment film is formed, and the formed droplets are dried, so that the spacer particles are effective at specific positions. Can be gathered together. Therefore, for example, the spacer particles can be arranged with high accuracy in a region corresponding to the non-pixel region of the substrate on which the alignment film is formed, and the display image quality of the liquid crystal display device to be manufactured can be improved.

The solvent X is not particularly limited as long as it has the above-described boiling point and surface tension. For example, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6- Examples include hexanediol, diethylene glycol, triethylene glycol, glycerin, 2-pyrrolidone, nitrobenzene and the like. Among them, 1,3-propanediol, 1,4-butanediol, and glycerin are preferably used because the spacer particles can be effectively gathered in a short time during drying. Since the spacer particles can be collected more effectively in a short time during drying, glycerin is more preferably used. These solvent X may be used independently and 2 or more types may be used together.

In the spacer particle dispersion of the present invention, as a preferable combination of the above-mentioned solvents, for example, a wetted part such as an ink chamber in a head of an inkjet apparatus described later (a part where the spacer particle dispersion of the present invention is in direct contact) is hydrophilic. And / or before filling the spacer particle dispersion, it is filled with a solvent having a low surface tension such as 2-propanol, which wets the ink chamber well. When the bubbles and the inside of the flow path and the head can be replaced with the spacer particle dispersion without removing the bubbles after sufficiently removing the bubbles (hereinafter also referred to as a solvent replacement method), the boiling point described above is 150 ° C. or higher and 20 ° C. A preferable lower limit of the solvent having a surface tension of 30 mN / m or more is 30% by weight, and a preferable upper limit is 96% by weight (more preferable lower limit is 45% by weight, more The upper limit is 94 wt%) Masui, preferred lower limit of the water 4% by weight and the desirable upper limit is 70 wt% (more preferred lower limit is 6% by weight, and more preferable upper limit can be mentioned a combination of a 55% by weight). When the solvent is in such a combination, if the water content is less than 4% by weight, the viscosity of the spacer particle dispersion of the present invention is too high, making it difficult to eject from the head of the ink jet apparatus (the driving voltage becomes too high). If the amount exceeds 70% by weight, the viscosity of the spacer particle dispersion of the present invention becomes too low, resulting in a problem that the discharge stability, particularly the stability in a high frequency driving state is lowered. There are things to do.

When the ink jet apparatus does not use the head or the solvent replacement method as described above, a preferable combination of the solvents is, for example, a solvent having a boiling point of less than 150 ° C. and a surface tension at 20 ° C. of less than 28 mN / m. A solvent having a lower limit of 2% by weight, a preferred upper limit of 40% by weight (more preferred lower limit is 5% by weight, more preferred upper limit is 20% by weight), and a boiling point of 150 ° C. or higher and a surface tension at 20 ° C. of 30 mN / m or higher. The preferred lower limit is 30% by weight, the preferred upper limit is 96% by weight (the more preferred lower limit is 40% by weight, the more preferred upper limit is 90% by weight), the preferred lower limit for water is 0% by weight, and the preferred upper limit is 60% by weight (more A preferable lower limit is 5% by weight, and a more preferable upper limit is 40% by weight). When the solvent is such a combination, the ratio of the solvent having the boiling point of less than 150 ° C. and the surface tension of less than 28 mN / m at 20 ° C. and water is the boiling point of 150 ° C. or more and 20 ° C. The amount excluding the solvent having a surface tension of 30 mN / m or more, that is, a preferable lower limit is 4% by weight, and a preferable upper limit is 70% by weight (more preferable lower limit is 6% by weight, and more preferable upper limit is 55% by weight).
If the solvent having a boiling point of less than 150 ° C. and a surface tension of less than 28 mN / m at 20 ° C. is less than 2% by weight, the surface tension of the spacer particle dispersion of the present invention becomes too high, and the spacer particle dispersion of the present invention When the ink is introduced into the head of the ink jet apparatus, there is a high probability that bubbles remain in the ink chamber and problems such as nozzles that do not discharge occur. If it exceeds 40% by weight, the surface tension of the spacer particle dispersion of the present invention becomes too low, and when the spacer particle dispersion of the present invention is discharged onto the substrate on which the alignment film is formed, There is a possibility that the landing diameter of the landed droplets becomes large and the spacer particles are difficult to gather together.
Further, when the amount of water and the boiling point of less than 150 ° C. and the solvent having a surface tension at 20 ° C. of less than 28 mN / m is less than 4% by weight, the viscosity of the spacer particle dispersion of the present invention is too high. In some cases, it becomes difficult to discharge from the head (driving voltage becomes too high), and when it exceeds 70% by weight, the viscosity of the spacer particle dispersion of the present invention becomes too low, and the discharge stability, particularly There may be a problem that the stability of the high frequency driving state is lowered.

Furthermore, when the spacer particle dispersion liquid of the present invention contains the solvent X described above as a solvent and spacer particles are gathered even on a substrate on which an alignment film having a high surface tension is formed, a preferable combination of the solvents is as follows: For example, the preferred lower limit of the solvent having a boiling point of less than 150 ° C. and a surface tension at 20 ° C. of less than 28 mN / m is 2% by weight, and a preferred upper limit is 40% by weight (more preferred lower limit is 5% by weight, more preferred upper limit is 20% by weight). %) And a preferable lower limit of the solvent having a boiling point of 150 ° C. or higher and a surface tension at 20 ° C. of 30 mN / m or higher is 0% by weight, a preferable upper limit is 95% by weight (more preferable lower limit is 40% by weight, and more preferable upper limit is 90% by weight) and the preferred lower limit of the solvent X is 1% by weight, and the preferred upper limit is 96% by weight (more preferred lower limit is 3% by weight, more preferred). Limit is 40 wt%), lower limit of water 0% by weight and the desirable upper limit is 60 wt% (more preferred lower limit is 5 wt%, and more preferable upper limit can be mentioned a combination of a 40 wt%). When the solvent containing the solvent X is such a combination, the preferred lower limit of the ratio of the solvent having the boiling point of less than 150 ° C. and the surface tension at 20 ° C. of less than 28 mN / m and water is 4 Solvent and solvent X having a weight percentage of 70% by weight and a preferred upper limit of 6% by weight (more preferred lower limit of 55% by weight), a boiling point of 150 ° C. or higher and a surface tension at 20 ° C. of 30 mN / m or higher. The preferable lower limit of the ratio of the above is 30% by weight, and the preferable upper limit is 96% by weight (the more preferable lower limit is 40% by weight, and the more preferable upper limit is 90% by weight).

If the solvent having a boiling point of less than 150 ° C. and a surface tension of less than 28 mN / m at 20 ° C. is less than 2% by weight, the surface tension of the spacer particle dispersion of the present invention becomes too high, and the spacer particle dispersion of the present invention When the ink is introduced into the head of the ink jet apparatus, there is a high probability that bubbles remain in the ink chamber and a problem that a nozzle that does not discharge occurs occurs. If it exceeds 40% by weight, the surface tension of the spacer particle dispersion of the present invention becomes too low, and when the spacer particle dispersion of the present invention is discharged onto the substrate on which the alignment film is formed, There may be a problem that the landing diameter of the landed droplets becomes large and the spacer particles are difficult to gather together.
Further, when the amount of water and the solvent having a boiling point of less than 150 ° C. and a solvent having a surface tension at 20 ° C. of less than 28 mN / m is less than 4% by weight, the viscosity of the spacer particle dispersion of the present invention is too high, There is a problem that it is difficult to eject from the head of the ink jet apparatus (driving voltage becomes too high), and when it exceeds 70% by weight, the viscosity of the spacer particle dispersion of the present invention becomes too low, and the ejection stability, In particular, there may be a problem that the stability in the high frequency driving state is lowered.
Furthermore, if the solvent X is less than 1% by weight, there may be a problem that spacer particles are difficult to gather on the substrate on which an alignment film having a high surface tension is formed. It takes a long time to dry the droplets of the spacer particle dispersion liquid of the present invention that has landed on the substrate on which the film is formed, resulting in a problem that productivity is lowered, or it is necessary to heat at a high temperature, and the alignment film is damaged. Problems such as high possibility occur.

For example, when the liquid contact part such as the ink chamber in the head of the ink jet apparatus is made of a highly hydrophilic material (SUS, ceramic, glass, etc.) and / or filled with the spacer particle dispersion of the present invention. Before filling with a solvent having a low surface tension such as 2-propanol which wets the ink chamber well, after sufficiently removing the bubbles, the spacer particle dispersion of the present invention prevents the bubbles from being involved. Can be substituted, a preferable combination of the above solvents does not require the addition of a solvent having a boiling point of less than 150 ° C. and a surface tension of less than 28 mN / m at 20 ° C., and other solvent combinations such as the above boiling point The preferred lower limit of the solvent having a surface tension at 20 ° C. of not less than 150 ° C. and not less than 30 mN / m is 0% by weight, and the preferred upper limit is 95% by weight (more preferred lower limit 40 wt%, more preferred upper limit is 90 wt%), the preferred lower limit of the solvent X is 1 wt%, the preferred upper limit is 96 wt% (more preferred lower limit is 3 wt%, more preferred upper limit is 40 wt%), A preferable lower limit of water is 4% by weight, and a preferable upper limit is 70% by weight (a more preferable lower limit is 6% by weight, and a more preferable upper limit is 55% by weight). When the solvent containing the solvent X is such a combination, a preferable lower limit of the ratio of the solvent having the boiling point of 150 ° C. or higher and the surface tension at 20 ° C. of 30 mN / m or more and the solvent X is 30. The preferred upper limit is 96% by weight (more preferred lower limit is 40% by weight, and more preferred upper limit is 90% by weight).
In the case where the solvent is such a combination, if the water is less than 4% by weight, the spacer particle dispersion of the present invention is too high in viscosity and difficult to eject from the head of the ink jet apparatus (the drive voltage becomes high). When the amount exceeds 70% by weight, the viscosity of the spacer particle dispersion of the present invention becomes too low, and the discharge stability, particularly the stability in a high frequency driving state, is lowered. Sometimes.
When the amount of the solvent X is less than 1% by weight, a problem that spacer particles hardly gather on the substrate on which an alignment film having a high surface tension is formed may occur. It takes a long time to dry the droplets of the spacer particle dispersion liquid of the present invention that has landed on the film, which may cause a problem of lowering productivity and may cause damage to the alignment film due to the necessity of heating at a high temperature. The problem of becoming high occurs.

The spacer particle dispersion of the present invention preferably has a viscosity during storage (20 ° C.) of greater than 3 mPa · s and less than 20 mPa · s. If it is 3 mPa · s or less, the spacer particles dispersed in the spacer particle dispersion of the present invention are likely to settle over time, and if the head of the inkjet device is a low viscosity and difficult to discharge, the cooling mechanism is However, even if it is attempted to increase the viscosity, there may be a problem that the viscosity cannot be discharged. When it is 20 mPa · s or more, when discharging using an inkjet apparatus, the head may be heated, and it may not be possible to discharge with a type of head that cannot lower the viscosity, or the discharge amount may be difficult to control. Occasionally, the spacer particle dispersion may need to be overheated to further improve ejection properties.
In addition, when using the head which can be heated, the preferable upper limit of the said viscosity is 100 mPa * s. This is because, even if the temperature can be increased, if the temperature is too high so as to lower the viscosity, the spacer particle dispersion and the head deteriorate, so that the temperature can only be increased up to about 60 ° C. More preferably, it is less than 20 mPa · s when heated to about 60 ° C.

Moreover, the preferable minimum of the viscosity at the time of discharge of the spacer particle dispersion liquid of this invention is 0.5 mPa * s, and a preferable upper limit is 20 mPa * s. If it is less than 0.5 mPa · s, even if it can be discharged, it may be difficult to control the discharge amount, and it may become impossible to discharge stably, and if it exceeds 20 mPa · s, it may not be able to be discharged by the ink jet device. . A more preferred lower limit is 5 mPa · s, and a more preferred upper limit is 15 mPa · s.
Here, the viscosity at the time of discharge means that when discharging the spacer particle dispersion of the present invention, the head temperature of the ink jet device is cooled by a Peltier element or a refrigerant, or heated by a heater or the like, It is the viscosity which adjusted the liquid temperature at the time of discharge of a spacer particle dispersion liquid between -5 degreeC and 50 degreeC. Of course, this is the ambient temperature for a head without a cooling and heating mechanism.

That is, the viscosity at the time of storage of the spacer particle dispersion of the present invention is within the range of viscosity that can be discharged by the head in any case of not controlling the viscosity at the time of discharge by heating and cooling, etc. It is preferable from the viewpoint.
These viscosities were measured at respective temperatures (measurement temperature and use temperature) with ordinary viscometers such as E-type viscometers and B-type viscometers.

The spacer particle dispersion of the present invention preferably has a settling rate of spacer particles of 30 minutes or more. The settling speed of the spacer particles can be adjusted by appropriately setting the kind and blending amount of the solvent contained in the spacer particle dispersion of the present invention, and the settling speed is 30 minutes or more. The spacer particles are less likely to settle during the period from the introduction of the spacer particle dispersion liquid into the ink jet apparatus until the discharge. Therefore, the spacer particle dispersion liquid of the present invention can be stably discharged using an ink jet device, and the spacer particles can be selectively and accurately arranged on the substrate. In this specification, “sedimentation velocity” means that the spacer particle dispersion of the present invention is introduced into a test tube having an inner diameter of 5 mm so as to have a height of 10 cm and then left to stand visually. The time until the deposition of spacer particles is confirmed at the bottom.

In addition, the spacer particle dispersion of the present invention preferably has a receding contact angle (θr) of 5 degrees or more with respect to the substrate on which the alignment film to be discharged is formed. If the receding contact angle is 5 degrees or more, the droplets of the spacer particle dispersion that have landed on the substrate on which the alignment film is formed are dried, shrink toward the center, and one in the droplets. The spacer particles contained above can be gathered near the center of the droplet. In addition, if charged ink due to electrostatically acting force is landed at the center in advance, or if there is a step within the diameter of the landed droplet, the movement of the spacer particles is more likely to occur. The accuracy is further improved.
The “receding contact angle” refers to drying after the droplets of the spacer particle dispersion liquid of the present invention placed on the substrate on which the alignment film is formed are placed on the substrate on which the alignment film is formed. In the process up to, the contact angle shown when the impact diameter starts to be smaller than when it is first placed on the substrate on which the alignment film is formed (when the droplet starts to shrink), or the volatile component of the droplet The contact angle indicated when 80 to 95% by weight of the solvent volatilizes.

Examples of the method of setting the receding contact angle to 5 degrees or more include a method of adjusting the composition of the mixed solvent of the spacer particle dispersion liquid of the present invention, a method of adjusting the surface of the substrate, and the like.

In order to set the receding contact angle (θr) of the spacer particle dispersion of the present invention to 5 ° or more, the receding contact angle (θr) of the solvent having the highest boiling point among the mixed solvents is 5 ° or more. Mix so that When the receding contact angle (θr) of the solvent having the highest boiling point is 5 ° or more, the weight of the droplet formed on the substrate on which the alignment film is formed is reduced by 5% by weight or more (hereinafter, this state is dried) The droplet diameter becomes smaller (also referred to as the later stage) (the droplet shrinks on the substrate), and the spacer particles are more likely to gather near the landing center on the substrate on which the alignment film is formed.

In the process of reaching the present invention, the receding contact angle tends to be smaller than the so-called contact angle (the initial contact angle when the droplet is placed on the substrate, which is usually called the contact angle in most cases). I found out that This is because the initial contact angle is the contact angle of the droplet with respect to the substrate on the surface of the substrate not in contact with the solvent constituting the spacer particle dispersion, whereas the receding contact angle constitutes the spacer particle dispersion. This is considered to be due to the contact angle of the droplet with respect to the substrate on the surface of the substrate after contacting with the solvent. That is, when the receding contact angle is significantly lower than the initial contact angle, it indicates that the alignment film is damaged by those solvents, and using these solvents can prevent the alignment film from being contaminated. It was also found that it was not preferable.

The spacer particle dispersion of the present invention preferably has an initial contact angle θ of 5 ° or more with the substrate on which the alignment film is formed. If the angle is less than 5 degrees, the droplets of the spacer particle dispersion liquid of the present invention discharged onto the substrate on which the alignment film is formed may be wet spread on the substrate and the spacing between the spacer particles may not be reduced. . The initial contact angle with the substrate on which the alignment film of the spacer particle dispersion of the present invention is formed is more preferably adjusted so that the lower limit is 10 degrees and the upper limit is 110 degrees. If it is greater than 110 degrees, the liquid droplets can easily move around on the substrate on which the alignment film is formed with a slight vibration, resulting in poor placement accuracy and poor adhesion between the spacer particles and the substrate on which the alignment film is formed. Sometimes it becomes.

Moreover, it is preferable that the spacer particle | grain dispersion liquid of this invention is disperse | distributing the spacer particle | grains to single particle form. When aggregates of spacer particles are present, not only the discharge accuracy of the spacer particle dispersion of the present invention using an ink jet apparatus is lowered, but also in some cases, the nozzles of the ink jet apparatus may be clogged.

In addition, the spacer particle dispersion of the present invention improves the dispersion of spacer particles within the range that does not impair the effects of the present invention, controls the physical properties such as surface tension and viscosity, improves the discharge accuracy, Various surfactants, viscosity modifiers, and the like may be added for the purpose of improving particle mobility.

Next, an inkjet apparatus that discharges the spacer particle dispersion of the present invention onto the substrate on which the alignment film is formed will be described.
The ink jet apparatus used in the present invention is not particularly limited. For example, a normal ejection such as a piezo system that ejects a liquid by vibration of a piezo element or a thermal system that ejects a liquid by utilizing the expansion of the liquid by rapid heating. An ink jet device according to the method is used. Among them, a piezo method having a small thermal influence on the discharged material such as the spacer particle dispersion of the present invention is preferably used.

It is preferable that the liquid contact portion of the ink chamber containing the spacer particle dispersion of the present invention of the ink jet apparatus is made of a hydrophilic material having a surface tension of 31 mN / m or more. Note that the wetted part may be subjected to a hydrophilic treatment with a chemical solution or the like to obtain a hydrophilic material having a surface tension of 31 mN / m or more.
As such a material, a hydrophilic organic material such as hydrophilic polyimide is used, or a head made of a material of a liquid contact part of a normal ink chamber is treated with a hydrophilizing agent (material of the liquid contact part). In addition, an inorganic material, that is, a metal material such as ceramic, glass, and stainless steel with low corrosiveness is preferably used in terms of durability.

In the head of a normal ink jet apparatus, resin or the like is used in this portion for insulation from voltage application components. However, in the case of such a material having a surface tension lower than 31 mN / m, the spacer particle dispersion liquid of the present invention is used. When the liquid is introduced into the head, the compatibility with the spacer particle dispersion liquid is poor, and bubbles tend to remain. If bubbles remain, the nozzle in which the bubbles remain may not be ejected, which is not preferable.

Moreover, it is preferable that the nozzle diameter of the said inkjet apparatus is 5 times or more with respect to a spacer particle diameter. If it is less than 5 times, the nozzle diameter may be too small compared to the spacer particle diameter and the discharge accuracy may be lowered, or if not, the nozzle may be blocked and discharge may not be possible. More preferably, it is 7 times or more.

The reason why the discharge accuracy is lowered is considered as follows. In the piezo method, ink is sucked into an ink chamber adjacent to the piezo element by vibration of the piezo element, or ink is ejected from the ink chamber through the tip of a nozzle. As a droplet discharge method, a meniscus (interface between ink and gas) at the tip of the nozzle is pulled in immediately before discharge, and then the liquid is pushed out and the liquid is pushed out directly from the position where the meniscus is on standby Although there is a method, in the general ink jet apparatus, the former striking method is the mainstream, and as a feature thereof, small droplets can be ejected. In the ejection of the spacer particle dispersion liquid of the present invention, the diameter of the nozzle is large to some extent and the ejection of small droplets is required, so this striking method is effective.

However, in the case of the pulling method, the meniscus is drawn immediately before the discharge, so that, for example, when the nozzle diameter is small such that the nozzle diameter is less than five times the particle diameter, the drawn meniscus 12 is shown in FIG. If there are spacer particles 11 in the vicinity, the meniscus 12 is not drawn in an axisymmetric manner. Therefore, it is considered that the liquid droplets of the spacer particle dispersion liquid 13 are not straight but bent during the extrusion after the drawing, and the discharge accuracy is lowered. For example, when the nozzle diameter is large such that the nozzle diameter is 7 times or more of the particle diameter, as shown in FIG. 2B, even if the spacer particles 11 are in the vicinity of the drawn meniscus 12, the spacer particles 11 Not affected. Therefore, it is considered that the meniscus 12 is drawn in an axisymmetric manner, and the liquid droplets of the spacer particle dispersion 13 advance straightly during the extrusion after the drawing and the discharge accuracy is improved. However, if the nozzle diameter is increased unnecessarily in order to eliminate the bending of the droplets during ejection, the ejected droplets become larger and the landing diameter becomes larger, so that the accuracy with which the charged ink and spacer particles 11 are arranged is improved. It becomes rough and is not preferable.

The amount of droplets ejected from the nozzle is preferably in the range of 10 to 80 pL in the case of a spacer particle dispersion. As a method for controlling the droplet amount, there are a method for optimizing the nozzle diameter and a method for optimizing an electric signal for controlling the ink jet head. The latter is particularly important when a piezo ink jet apparatus is used.

In the ink jet apparatus, the ink jet head is provided with a plurality of nozzles as described above in a fixed arrangement. For example, 64 or 128 are provided at equal intervals in a direction orthogonal to the moving direction of the head. In some cases, these are provided in a plurality of rows such as two rows.

The interval between the nozzles is restricted by the structure of the piezoelectric element and the nozzle diameter. Therefore, when the spacer particle dispersion of the present invention is discharged onto the substrate at intervals other than the intervals at which the nozzles are arranged, it is difficult to prepare a head at each discharge interval. Accordingly, when the distance is smaller than the distance between the heads, the head, which is normally arranged at right angles to the scanning direction of the head, is discharged while being tilted or rotated in a plane parallel to the substrate while being parallel to the substrate. When the interval is larger than the interval between the heads, the discharge is not performed by all the nozzles, but is performed by discharging only a certain nozzle, or by additionally tilting the head.

In order to increase productivity, a plurality of such heads can be attached to the ink jet apparatus. However, if the number of attachments is increased, the control becomes complicated, so care must be taken.

FIGS. 8A and 8B schematically show an example of a head of an ink jet apparatus used in the present invention. FIG. 8A is a partially cutaway perspective view schematically showing the structure of an example of an ink jet head, and FIG. 8B is a partially cutaway perspective view showing a cross section of the nozzle hole portion.
As shown in FIGS. 8A and 8B, the head 100 includes an ink chamber 101 in which the spacer particle dispersion of the present invention is filled in advance by suction or the like, and the spacer of the present invention from the ink chamber 101. An ink chamber 102 into which the particle dispersion is fed is provided. A nozzle hole 104 extending from the ink chamber 102 to the ejection surface 103 is formed in the head 100. The discharge surface 103 is previously subjected to water repellent treatment in order to prevent contamination by the spacer particle dispersion of the present invention. The head 100 is provided with temperature control means 105 for adjusting the viscosity of the spacer particle dispersion of the present invention. The head 100 includes a piezo element 106 that functions to send the spacer particle dispersion of the present invention from the ink chamber 101 to the ink chamber 102 and further functions to discharge the spacer particle dispersion of the present invention from the nozzle hole 104. ing.

Since the temperature control means 105 is provided in the head 100, when the viscosity of the spacer particle dispersion of the present invention is too high, the spacer particle dispersion of the present invention is heated by a heater to reduce the viscosity. When the viscosity of the spacer particle dispersion of the present invention is too low, the spacer particle dispersion of the present invention can be cooled by Peltier to increase the viscosity.

The substrate for discharging the spacer particle dispersion of the present invention using such an ink jet device may be any of two substrates constituting a liquid crystal display device having a conventionally known structure. Of these two substrates, one substrate is, for example, one that is used as a panel substrate of a normal liquid crystal display device such as glass or resin. An example of the substrate is a substrate in which a color filter is provided in a pixel region. In this case, the pixel region of the liquid crystal display device is defined by a black matrix such as a resin in which a metal such as chrome or carbon black that substantially does not transmit light is dispersed. This black matrix constitutes a non-pixel region.

As the alignment film formed on the substrate, a polyimide resin film is usually used. The polyimide resin film can be obtained by discharging a solvent-soluble polyamic acid onto a substrate and then thermally polymerizing it, or discharging a soluble polyimide resin onto a substrate and then drying it. As these polyimide resins, those having a long side chain and a main chain are more preferable for obtaining a low energy surface. In order to control the alignment of the liquid crystal, the alignment film may be rubbed on the surface after coating. In addition, it is necessary to select the solvent of the above-mentioned spacer particle dispersion liquid that does not contaminate the alignment film by permeating or dissolving in the alignment film.
Further, by forming an alignment film on the substrate, the surface of the substrate can be a low energy surface, and the receding contact angle of the droplet formed by discharging the spacer particle dispersion of the present invention described above is 5 degrees. This is possible.

As described above, the spacer particle dispersion of the present invention contains an adhesive that fixes spacer particles arranged on the alignment film formed on the substrate to the alignment film, and is a cured product of the adhesive. Is harder than the spacer particles, and therefore, in the manufacturing process of the liquid crystal display device, it is possible to prevent the yield from being lowered due to the non-uniform height of the spacer particles, and to have excellent display quality. Can be manufactured.

A method for producing a liquid crystal display device using the spacer particle dispersion of the present invention is not particularly limited. For example, the liquid of the spacer particle dispersion of the present invention using an inkjet device on the substrate on which the alignment film is formed. Examples of the method include a step of ejecting a droplet to place the droplet, a step of drying the droplet to aggregate the spacer particles, and a step of superimposing the other substrate through the spacer particles.

In the step of ejecting the droplets of the spacer particle dispersion liquid of the present invention on the substrate on which the alignment film is formed in the method for manufacturing the liquid crystal display device by using the ink jet device to place the droplets, the spacer particles of the present invention As a location for discharging the dispersion liquid, for example, the dispersion liquid may be randomly arranged on the substrate on which the alignment film is formed, or may be arranged in a pattern at a specific position. Among these, it is preferable to arrange the liquid crystal display device in a pattern at a specific position for the purpose of suppressing deterioration in display image quality caused by spacer particles such as light leakage in a liquid crystal display device to be manufactured. Specifically, it is preferable to discharge the spacer particles so as to be arranged in the non-display area of the liquid crystal display device.
In the following description, a case where the spacer particle dispersion of the present invention is arranged in a pattern at a specific position will be described.

Examples of the non-display region of the liquid crystal display device include a region where a black matrix of the liquid crystal display device having the structure described with reference to FIG. 1 is formed. Note that such a liquid crystal display device has a pixel region other than the non-pixel region, and examples of the pixel region include a region where a color filter in the liquid crystal display device shown in FIG. 1 is formed.

In this step, the spacer particle dispersion of the present invention is discharged onto the surface of the substrate on which the alignment film has been formed, using an inkjet apparatus. At this time, it is more preferable that the location where the droplets of the spacer particle dispersion are discharged and landed on the substrate is adjusted so that the initial contact angle of the spacer particle dispersion of the present invention is 5 degrees or more.

Examples of the method for increasing the initial contact angle on the substrate include a method in which the surface of the substrate is a low energy surface.
As a method for making the surface of the substrate a low energy surface, a method of coating a resin having a low energy surface such as a fluorine film or a silicone film may be used. Since the above-mentioned alignment film for regulation is provided, the substrate surface can be made a low energy surface by appropriately adjusting a resin such as a polyimide resin constituting the alignment film.

Note that the substrate on which the alignment film on which the spacer particle dispersion of the present invention is discharged is formed has a portion having a low energy surface in the region corresponding to the non-pixel region, and the droplet after landing is low. It is preferable that the droplets of the spacer particle dispersion liquid of the present invention be landed so as to exist in a portion having an energy surface.
Here, the region corresponding to the non-pixel region is the non-pixel region (the above-described black matrix for a color filter substrate) or the other substrate (a TFT array substrate for a TFT liquid crystal panel). When the substrate is overlapped with a substrate having a non-pixel region, it indicates one of regions corresponding to the region having the non-pixel region (such as a wiring portion in the case of a TFT array substrate).

The surface energy of the portion having the low energy surface is preferably 45 mN / m or less, more preferably 40 mN / m or less. If it exceeds 45 mN / m, as long as the spacer particle dispersion liquid of the present invention having a surface tension that can be discharged by an ink jet apparatus is used, the droplets wet and spread on the substrate, and the spacer particles protrude from the non-pixel region. .

The low energy surface obtained by applying the alignment film or the like may be only the location where the spacer particles land, or the entire surface of the substrate. Considering processes such as patterning, the entire surface is usually a low energy surface.

Moreover, the location where the droplet of the spacer particle dispersion liquid of the present invention is landed may include a location having a step and a periphery. In addition, it is more preferable that the charged ink is discharged and dried only at a portion having a step.

In addition, the level | step difference here means the unintentional unevenness (level difference with the circumference | surroundings) produced by the wiring etc. which were provided on the board | substrate, or the unevenness provided intentionally in order to collect spacer particles, The structure under the uneven surface is not limited. Therefore, the step here refers to a step between a concave portion or a convex portion and a flat portion (reference surface) in the surface uneven shape.

Specifically, for example, in an array substrate in a TFT liquid crystal panel, a step (about 0.2 μm) due to a gate electrode or a source electrode as shown in FIGS. 3A to 3C, FIG. ), A step (about 1.0 μm) due to the array as shown in FIG. Furthermore, with color filter substrates. Examples thereof include a concave step (about 1.0 μm) between the image color filters on the black matrix as shown in FIGS. 3D to 3F and 3H.

In this case, when the spacer particle diameter is D (μm) and the step is B (μm), the step is preferably a step having a relationship of 0.01 μm <| B | <0.95D. If it is smaller than 0.01 μm, it may be difficult to collect spacer particles around the step, and if it exceeds 0.95 D, it may be difficult to obtain a substrate gap adjusting effect by the spacer particles.

As for the effect of the step, if there is a step, the droplet drying center is pseudo-fixed to the step portion at the final stage of drying, so that after the landing droplet of the spacer particle dispersion liquid of the present invention has dried It is explained that the spacer particles can be collected at a very limited position around the step in the region corresponding to the non-pixel region.
In this case, as shown in FIG. 4, the position where the spacer particles 11 finally remain after drying is often a corner if it is a convex part, or in a recess if it is a concave part.

Regarding the effect of the step, if there is a metal in the vicinity of a step portion such as a wiring or a thin film such as an alignment film and the spacer particles are surface-modified or contain a charge control agent, Electrical interaction It is also considered that particles are moved and adsorbed by the so-called electrostatic “electrophoresis” effect. In this case, the metal species and, for example, the functional group of the compound used for the surface treatment such as wiring is changed by using an ionic functional group, or the charge control agent is added while adjusting the type, Alternatively, a positive or negative voltage is applied to the wiring such as the source wiring and the gate wiring and the entire surface of the substrate so as not to damage the circuit. In this way, the crowding of the spacer particles can be controlled.

In this step, the spacer particle dispersion of the present invention is discharged to a specific position corresponding to the non-pixel region of the substrate described above using an ink jet device. Specifically, the spacer particle dispersion of the present invention is discharged to a position including a non-pixel region on the surface of the substrate on which the alignment film is formed.

In this step, it is preferable that the spacer particle dispersion liquid of the present invention is discharged onto the substrate on which the alignment film is formed with an interval of the following formula (1) or more. This interval is the minimum interval between the droplets when the next droplet is ejected while the landed droplets of the spacer particle dispersion of the present invention are not dried.

In the above formula (1), D represents the particle diameter (μm) of the spacer particles, and θ represents the initial contact angle between the spacer particle dispersion of the present invention and the substrate surface.

If the droplets are ejected at an interval smaller than the above formula (1), the droplet diameter remains large, the landing diameter also increases and droplet coalescence occurs, and the aggregation direction of the spacer particles occurs toward one place during the drying process. Disappear. As a result, there arises a problem that the arrangement accuracy of the spacer particles after drying is deteriorated. Further, when the nozzle diameter is reduced to reduce the discharge droplet amount, the spacer particle diameter becomes relatively larger than the nozzle diameter, so that it is more stable than the inkjet head nozzle as described in the spacer particle dispersion of the present invention. Thus, for example, the spacer particles cannot always be ejected linearly in the same direction, and the landing position accuracy decreases due to the flight bend. Further, the nozzle may be blocked by the spacer particles.

The arrangement number (dispersion density) of the spacer particles arranged on the substrate on which the alignment film is formed by discharging as in the above formula (1) is usually preferably 50 to 500 / mm ² . The spray density is appropriately adjusted depending on the substrate to be arranged, the gap to be obtained, the difference in the particle diameter of the spacer particles to be used, and the like. In general, when it is desired to reduce the deformation amount of the spacer particles (difference between the gap to be obtained and the particle size of the spacer particles to be used) as much as possible, the appropriate value of the spraying density is 150 to 1000 particles / mm ² . If not, it is 50 to 350 / mm ² . Any pattern may be arranged in any part of the region corresponding to the non-pixel region such as black matrix and the non-pixel region such as wiring as long as the particle density is satisfied. However, in order to prevent protrusion to the display portion (pixel region), for a color filter composed of a lattice-shaped light-shielding region (non-pixel region), the lattice point of the lattice-shaped light-shielding region on one substrate It is more preferable to arrange for the corresponding part.
The number of spacer particles at one arrangement position varies depending on the arrangement position, but is generally about 0 to 100, and the average number is about 2 to 50. The average number is adjusted by the particle diameter of the spacer particles and the concentration of the spacer particle dispersion of the present invention.

In addition, in this way, in order to discharge the spacer particle dispersion of the present invention and land the droplets on the substrate on which the alignment film is formed, the scanning of the ink jet head can be performed once or divided into a plurality of times. It can also be done. In particular, when the interval at which the spacer particles are to be arranged is narrower than the above formula (1), the particles are discharged at an integer multiple of the interval, dried once, shifted by the interval, and then discharged again. May be. With respect to the moving (scanning) direction as well, it can be alternately changed (reciprocating discharge) for each discharge and discharged only when moving in one direction (unidirectional discharge).

Further, as such an arrangement method, as disclosed in Japanese Patent Application No. 2000-194556, the head is tilted so as to have an angle with a perpendicular to the substrate surface, and the droplet discharge direction is changed (usually parallel to the perpendicular to the substrate surface). ) Further, the relative speed between the head and the substrate is controlled. By doing so, it is also possible to reduce the diameter of the droplets that land and make it easier to arrange the spacer particles in the non-pixel region or the region corresponding thereto.

In this step, the substrate surface temperature when the spacer particle dispersion liquid of the present invention is landed on the substrate is 20 ° C. or more lower than the boiling point of the lowest boiling solvent contained in the spacer particle dispersion liquid of the present invention. Preferably there is. When the temperature is higher by 20 ° C. than the boiling point of the lowest boiling point solvent, the lowest boiling point solvent volatilizes rapidly, and not only the spacer particles cannot move. And the spacer particle placement accuracy may be significantly reduced. More preferably, it is around room temperature (15 to 35 ° C.).

The manufacturing method includes the step of aggregating the spacer particles in the droplets of the spacer particle dispersion of the present invention.
In this step, the spacer particles are aggregated in the droplets of the spacer particle dispersion liquid of the present invention arranged at a specific position corresponding to the non-pixel region on the substrate in the above-described step. Specifically, the solvent in the droplet is dried.

The method of drying the droplets is not particularly limited, and examples thereof include a method of heating the substrate, blowing hot air or cold air, or drying under reduced pressure. However, in order to gather the spacer particles near the droplet landing center in this step, the boiling point of the solvent, the drying temperature, the drying time, the surface tension of the solvent, the contact angle of the solvent with respect to the alignment film, the concentration of the spacer particles, etc. It is preferable to set an appropriate condition.

In order to agglomerate the spacer particles in the droplets in this step, the spacer particles are dried with a certain time width so that the solvent does not disappear while the spacer particles move on the substrate. For this reason, the conditions for the solvent to dry rapidly are not preferred.
In addition, the solvent is not preferable if it contacts the alignment film at a high temperature because the alignment film may be contaminated and the display image quality of the liquid crystal display device may be impaired. Accordingly, the substrate surface temperature until the drying is completed is preferably 90 ° C. or less, more preferably 60 ° C. or less. If the substrate temperature until the drying is completed exceeds 90 ° C., the alignment film may be damaged and the display image quality of the liquid crystal display device may be impaired.

It is not preferable to use a solvent that is remarkably volatile at room temperature or a solvent that violently evaporates, because the spacer particle dispersion near the nozzles of the ink jet device is easily dried and impairs the ink jetting properties. In addition, spacer particles may be aggregated during the production of the dispersion or by drying in a tank, which is not preferable.

Even if the substrate temperature is relatively low, if the drying time is remarkably long, not only the production efficiency of the liquid crystal display device is reduced, but also the solvent of the spacer particle dispersion liquid is in contact with the alignment film for a long time. This causes undesirable contamination and damage of the alignment film.

In this step, when the droplet is dried while gradually raising the substrate temperature, the substrate surface temperature until the drying is completed is preferably 90 ° C. or less, more preferably 60 ° C. or less. If the substrate temperature until the drying is completed exceeds 90 ° C., it is not preferable because the alignment film is damaged and the display image quality of the liquid crystal display device is impaired.

As described above, as a drying method for preventing the alignment film from being damaged, it is preferable to complete the drying in a short time at as low a temperature as possible. Specifically, it is preferable that the surface temperature of the substrate is set to 60 ° C. or less, and the droplets are dried within 5 seconds to 4 minutes (more preferably within 5 seconds to 2 minutes) after the droplets contact. . If the drying is performed in an excessively short time, the aggregation of the spacer particles is deteriorated as described above, and if it takes a long time, the alignment film may be damaged.
As a means for achieving this, there is a method of quickly removing the solvent vapor in the vicinity of the droplets, that is, applying a wind or drying under reduced pressure. However, if the air flow is too strong, the spacer particles move around in the droplets, and as a result, the aggregation of the spacer particles is inhibited. Therefore, the air flow needs to be adjusted as appropriate.
Further, depending on the type of the alignment film, in order to improve the aggregation of the spacer particles, the alignment film may be dried at a high temperature exceeding 90 ° C. in a short time. Specifically, it is preferable to perform drying at 100 to 150 ° C. for about 5 to 20 seconds.
In the present invention, the completion of drying means the time when the solvent of the droplets on the substrate disappears.

Here, the spacer particle dispersion of the present invention contains an adhesive, and the adhesive is gathered near the spacer particles aggregated in this step. Therefore, in this step, after the drying of the droplets is completed, the adhesive is used to increase the adhesion of the spacer particles to the substrate (alignment film) and to remove the residual solvent, so that a higher temperature (about 120 to 230 ° C.) It is preferable to heat the substrate.

The manufacturing method of the liquid crystal display device includes a step of superposing the substrate on which the alignment film is formed and another substrate so as to face each other through the liquid crystal and the agglomerated spacer particles.

Specifically, in this step, the substrate on which the spacer particles are arranged in the above step is thermocompression-bonded using a substrate on which the spacer particles are not arranged and a peripheral sealing agent, and a liquid crystal is formed in the gap between the formed substrates. Filled to produce a liquid crystal display (vacuum injection method). Alternatively, a peripheral sealing agent is applied to one substrate, a liquid crystal is dropped within a range surrounded by the substrate, and the liquid crystal display device is manufactured by bonding the other substrate and curing the sealing agent (liquid crystal dropping method) ). In this case, spacer particles may be disposed on any substrate.

According to the manufacturing method of the liquid crystal display device, the spacer particle dispersion liquid of the present invention can be continuously and stably discharged onto the substrate surface using an ink jet device, and the manufactured liquid crystal display device has spacer particles arranged in the pixel region. Thus, the display quality is excellent.
A liquid crystal device using such a spacer particle dispersion of the present invention is also one aspect of the present invention.

According to the present invention, in the manufacturing process of the liquid crystal display device, the spacer can prevent the yield from being lowered due to the non-uniform height of the spacer particles and can manufacture the liquid crystal display device having excellent display quality. A particle dispersion and a liquid crystal display device using the spacer dispersion can be provided.

Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples.

(Preparation of spacer particles)
In a separable flask, 15 parts by weight of divinylbenzene, 5 parts by weight of isooctyl acrylate, and 1.3 parts by weight of benzoyl peroxide as a polymerization initiator were uniformly mixed. Next, 20 parts by weight of a 3% aqueous solution of polyvinyl alcohol (trade name “Kuraray Poval GL-03”, manufactured by Kuraray Co., Ltd.) and 0.5 parts by weight of sodium dodecyl sulfate were added and stirred well. Thereafter, 140 parts by weight of ion-exchanged water was added. The solution was reacted at 80 ° C. for 15 hours under a nitrogen stream while stirring. The obtained particles were washed with hot water and acetone and then classified to obtain spacer particles having an average particle size of 4.0 μm and a CV value of 3.0%.

(Preparation of adhesive)
Into a 1 L separable flask, the acrylic monomer and solvent shown in Table 1 were added and mixed well. After dissolved oxygen was purged by nitrogen bubbling and heated to 60 ° C., the initiator (V-65, 2,2′-azobis) (2,4-dimethylvaleronitrile)) was added in an amount of 1 part by weight based on the total amount of monomers, and a polymerization reaction was carried out for 8 hours. When the molecular weight of the resulting polymer was measured by GPC, it was as shown in Table 1.

(Preparation of spacer particle dispersion)
The spacer particles obtained by the above-mentioned method take a necessary amount so as to have a predetermined particle concentration, slowly add to the solvent having the composition described in Table 2 below, and disperse by thoroughly stirring while irradiating with ultrasonic waves. It was. Thereafter, the mixture was filtered with a stainless mesh having an opening of 10 μm to remove aggregates, and spacer particle dispersions according to Examples 1 to 6 and Comparative Examples 1 and 2 were obtained.

(Production of substrate)
A color filter substrate was used as the substrate for the liquid crystal test panel, and a TFT array model substrate imitating a step in the TFT array substrate was used as the other substrate.

(Color filter substrate)
FIG. 5A is an enlarged partial cutaway plan view showing a part of a state in which a black matrix is provided on a glass substrate used for a color filter substrate. FIG. 5B is an enlarged partial cutaway front sectional view showing a part of the color filter substrate.
The color filter substrate 21 having a smooth surface used in Examples and Comparative Examples was produced as follows.

As shown in FIGS. 5A and 5B, a black matrix 23 (width 25 μm, vertical interval 150 μm, horizontal interval 75 μm) made of metallic chromium on a 300 mm × 360 mm glass substrate 22 by a normal method. , Thickness 0.2 μm). On and between the black matrix 23, color filter 24 pixels (thickness 1.5 μm) composed of three colors of red, green and blue were formed so as to have a flat surface. An overcoat layer 25 having a substantially constant thickness was provided thereon.
Further thereon, a polyimide resin solution was applied by spin coating. After coating, the film was dried at 150 ° C., then baked at 230 ° C. for 1 hour, and cured to form an alignment film 27 having a substantially constant thickness. At this time, in order to form any of the alignment films of PI1, PI2, and PI3, any one of the following three different polyimide resin solutions was used. The surface tension (γ) of the formed alignment film was as follows.

PI1: Trade name “Sunever SE130”, manufactured by Nissan Chemical Co., Ltd., surface tension (γ): 46 mN / m)
PI2: Trade name “Sunever SE150”, manufactured by Nissan Chemical Co., Ltd., surface tension (γ): 39 mN / m)
PI3: trade name “Sunever SE1211”, manufactured by Nissan Chemical Co., Ltd., surface tension (γ): 26 mN / m)

(TFT array model substrate)
FIG. 6A is a partially cutaway plan view showing a part of a state in which a step is provided on a glass substrate used for a TFT array model substrate. FIG. 6B is a partially cutaway front view showing an enlarged part of the TFT array model substrate.
The TFT array model substrate 31 provided with the steps was manufactured as follows.

As shown in FIGS. 6A and 6B, the TFT array model substrate 31 is placed on a 300 mm × 360 mm glass substrate 32 at a position facing the black matrix 23 of the color filter substrate 21. A step 33 (width 8 μm, height difference 5 nm) made of copper was provided by a known method. An ITO transparent electrode 34 having a substantially constant thickness was provided thereon, and an alignment film 35 having a substantially constant thickness was formed by the method described above. In the TFT array model substrate 31, the alignment film 35 was formed using the same polyimide resin solution as that of the counter substrate.

(Inkjet device)
An inkjet apparatus equipped with a piezo-type head having an aperture of 50 μm (optimum discharge viscosity range of 10 to 20 mPa · s can be heated) was prepared. The liquid contact part of the ink chamber of this head was made of a glass ceramic material, and the nozzle surface used was subjected to a fluorine-based water repellent finish.

(Spacer particle arrangement by inkjet method)
In this example and comparative example, spacer particles were arranged by the following method using the spacer particle dispersion shown in Table 2, the color filter substrate 21, and the TFT array model substrate 31. When arranging the spacer particles, the arrangement is started after discarding 0.5 mL of the initial spacer particle dispersion liquid discharged from the nozzle of the ink jet apparatus. In Table 2, when the color filter substrate is used, “21” ”And“ 31 ”when a TFT array model substrate is used. In addition, the spacer is arranged on the overcoat layer or the alignment film layer, the substrate in which the spacer is arranged on the overcoat is denoted as “O”, and the substrate in which the spacer is arranged on the alignment film is denoted as “P”. Indicated.

First, the color filter substrate 21 having the steps shown in FIG. 5 was placed on the stage. On this color filter substrate 21, using the above-described ink jet device, aiming at the black matrix 23 portion, the spacer particles shown in Table 2 at intervals of 390 μm on every other vertical line and on the vertical line. The droplets of the dispersion liquid were ejected at a pitch of 390 μm in length and 130 μm in width, arranged, and then dried on a hot plate heated to 45 ° C. The distance between the nozzle (head surface) and the substrate during ejection was 0.5 mm, and a double pulse method was used.

After confirming that the spacer particle dispersion liquid discharged on the color filter substrate 21 on the stage was completely dried by visual observation, the remaining solvent was further removed and transferred to a hot plate heated to 150 ° C. The mixture was heated and left for 15 minutes to fix the spacer particles to the substrate with an adhesive. In addition, when discharged as it is, the spacer particle dispersion having a viscosity of more than 15 mPa · s was discharged while being heated so that the viscosity was in the range of 3 to 15 mPa · s.

A TFT array model substrate 31 having a step 33 shown in FIG. 6 was placed on the stage. On this substrate, using the ink jet device described above, aiming at the step 33 corresponding to the black matrix 23, every other vertical line, on the vertical line, the spacers shown in Table 2 at intervals of 390 μm The droplets of the particle dispersion were discharged and arranged at a pitch of 390 μm in length and 130 μm in width, and then dried on a hot plate heated to 45 ° C. The distance between the nozzle (head surface) and the substrate during ejection was 0.5 mm, and a double pulse method was used.

(Production of liquid crystal display device for evaluation)
As described above, the color filter substrate 21 in which the spacer particles are arranged on either side and the TFT array model substrate 31 as the counter substrate were bonded together using a peripheral sealant. After bonding, the sealing agent is heated and cured at 150 ° C. for 1 hour to produce an empty cell in which the cell gap becomes the particle size of the spacer particles, and then filled with liquid crystal by a vacuum method, A liquid crystal display device was manufactured by sealing the inlet.

(Evaluation)
The following items were evaluated. The results are shown in Table 2.
(Glass transition temperature of cured adhesive)
The glass transition temperature of the cured adhesive was measured by a commonly used method using DSC.

(Integrity between cured adhesive and spacer particles)
A load was applied to the completed cell up to 78 N with a hard rubber having a diameter of 10 mm, and color unevenness in the weighted portion was observed after 1 minute of load release.
○: No color unevenness.
Δ: Slight color unevenness is observed.
X: Color unevenness is clearly observed.

(Spacer particle dispersion density)
After the spacer particles were fixed to the substrate, the number of spacer particles dispersed per 1 mm ² was observed to obtain the distribution density.

(Average number of spacer particles)
An average value of the number of spacer particles aggregated per one arrangement position was measured within the range of 1 mm ² .

(Spacer particle placement accuracy)
The arrangement state of the spacer particles after the droplets were dried was determined according to the following criteria.
○: Almost all the spacer particles were in a specific position (light shielding region) corresponding to the non-pixel region.
(Triangle | delta): Some spacer particle | grains existed in the position protruded from the specific position (light-shielding area | region) corresponding to a non-pixel area | region.
X: Many spacer particles were in a position protruding from a specific position (light shielding area) corresponding to the non-pixel area.

(Spacer particle dispersion density)
After the spacer particles were fixed to the substrate, the number of spacer particles dispersed per 1 mm ² was observed to obtain the distribution density.

(Spacer particle existence range)
As shown in FIG. 7, parallel lines are drawn at equal intervals on both sides from the center of the black matrix or the corresponding portion, and 95% or more spacer particles are present between the two parallel lines. The distance between the existing parallel lines was defined as the spacer particle existence range.

According to the present invention, in the manufacturing process of a liquid crystal display device, it is possible to prevent a decrease in yield due to uneven height of spacer particles, and to manufacture a liquid crystal display device excellent in display quality. A spacer particle dispersion and a liquid crystal display device using the spacer dispersion can be provided.

Front sectional drawing which shows the conventional liquid crystal display device typically. It is a schematic diagram showing the droplet discharge state from an inkjet nozzle, (a) shows the case where a meniscus is not an axis object, and (b) shows the case where a meniscus is an axis object. (A)-(h) is a cut-part end view which follows the cross-sectional direction of the level | step-difference part provided in the surface of the board | substrate. (A)-(c) is a schematic diagram showing the position where spacer particle | grains remain. (A) is a partial notch top view which expands and shows a part of state in which the black matrix was provided in the glass substrate used for the color filter board | substrate used by an Example and a comparative example. (B) is a partial notch front sectional view which expands and shows a part of color filter board | substrate used by an Example and a comparative example. (A) is a partial notch top view which expands and shows a part of state in which the level | step difference was provided in the glass substrate used for the TFT array model board | substrate used by an Example and a comparative example. (B) is a partial notch front view which expands and shows a part of TFT array model board | substrate used by an Example and a comparative example. The schematic diagram which shows the evaluation method of the existence range of spacer particle | grains. (A), (b) is the partial notch perspective view which shows typically the structure of an example of an inkjet head, and the partial notch perspective view which shows the cross section in a nozzle hole part. It is a schematic diagram which shows typically a mode when external force is added to the liquid crystal cell using the spacer particle dispersion liquid of this invention. It is a schematic diagram which shows the state which adhered the spacer particle | grain to the board | substrate with the adhesive agent. It is a schematic diagram which shows typically a mode when external force is added to the liquid crystal cell formed using the conventional spacer particle dispersion.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Transparent substrate 2 Polarizing plate 3 Transparent electrode 4 Color filter 5 Black matrix 6 Liquid crystal 7 Spacer particle 8 Resin film 9 Sealing material 11 Spacer particle 12 Meniscus 13 Spacer particle dispersion 14, 15 Adhesive hardened material 21 Color filter substrate 22 Glass substrate 23 Black matrix 24 Color filter 25 Overcoat layer 26 Transparent electrode 27 Alignment film 31 TFT array model substrate 32 Glass substrate 33 Step 34 Transparent electrode 35 Transparent electrode 100 Head 101 Ink chamber 1 (common ink chamber)
102 Ink chamber 2 (pressure ink chamber)
103 Discharge surface (nozzle surface)
104 Nozzle hole 105 Temperature control means 106 Piezo element

Claims (3)

A spacer particle dispersion containing spacer particles, an adhesive, and a solvent, and used when arranging the spacer particles at an arbitrary position on a substrate on which a resin film of a liquid crystal display device is formed using an inkjet device. A spacer particle dispersion, wherein the cured product of the adhesive is equal to or harder than the spacer particles. A spacer particle dispersion containing spacer particles, an adhesive, and a solvent, and used when arranging the spacer particles at an arbitrary position on a substrate on which a resin film of a liquid crystal display device is formed using an inkjet device. The spacer particle dispersion is characterized in that the adhesive has a cured product having a glass transition temperature of 80 ° C. or higher. A liquid crystal display device comprising the spacer particle dispersion according to claim 1.

Images