JP4733763B2 - Spacer particle dispersion - Google Patents

Description

The present invention relates to a method of manufacturing a liquid crystal display device including a step of arranging spacer particles on a substrate using an ink jet device, and more specifically, arranging spacer particles at a specific position on a substrate with high accuracy. The present invention relates to a method for manufacturing a liquid crystal display device that enables the liquid crystal display device, a liquid crystal display device obtained by the method for manufacturing the liquid crystal display device, and a spacer particle dispersion.

Liquid crystal display devices are currently widely used in personal computers, portable electronic devices, and the like. FIG. 11 is a front sectional view schematically showing an example of a conventional liquid crystal display device. In the liquid crystal display device 200 shown in FIG. 11, two transparent substrates 201 and 202 are disposed so as to face each other.

On the inner surface of the transparent substrate 201, a color filter 203 and a black matrix 204 that defines the color filter 203 are formed, and an overcoat layer 205 is formed on the color filter 203 and the black matrix 204. Further, an alignment film 207 is formed on the overcoat layer 205 so as to cover the transparent electrode 206 and the transparent electrode 206.

On the other hand, a transparent electrode 208 is formed on the inner surface of the transparent substrate 202 at a position facing the color filter 203, and an alignment film 209 is formed so as to cover the inner surface of the transparent substrate 202 and the transparent electrode 208. Is formed. The transparent electrodes 206 and 208 include a pixel electrode disposed in the pixel region and an electrode disposed outside the pixel region.
Further, the transparent substrates 201 and 202 are provided with polarizing plates 210 and 211 on their outer surfaces, respectively, and are bonded to each other in the vicinity of their outer peripheral edges via a sealing material 212.

Further, liquid crystal 214 is sealed in a space surrounded by the alignment films 207 and 209 and the sealant 202, and spacer particles 213 are disposed between the alignment film 207 and the alignment film 209. The spacer particles 213 function to regulate the distance between the two transparent substrates 201 and 202 and maintain an appropriate liquid crystal layer thickness, that is, a cell gap.

In the conventional method of manufacturing a liquid crystal display device, spacer particles are randomly and uniformly distributed on a substrate on which pixel electrodes are formed. Therefore, as shown in FIG. 11, on the pixel electrodes, that is, in the pixel region of the liquid crystal display device. Spacer particles were easily arranged. Since general spacer particles are made of synthetic resin, glass, or the like, when the spacer particles are arranged on the pixel electrode, a phenomenon in which the polarization is disturbed and the polarization property is lost, so-called depolarization phenomenon occurs. There was a problem that the part leaked light. Further, the alignment of the liquid crystal on the surface of the spacer particles may cause a problem that light is lost and the contrast and color tone are lowered to deteriorate the display quality.
Furthermore, in the TFT liquid crystal display device, the TFT element is disposed on the substrate. However, when spacer particles are disposed on the TFT element, the element may be damaged if pressure is applied to the substrate. .

In order to solve the problems associated with the random dispersion of the spacer particles, various attempts have been made to arrange the spacer particles in the non-pixel region.
As a method of disposing spacer particles only in a non-pixel region, that is, a specific position, for example, Patent Document 1 discloses a method in which a spacer opening is matched with a portion where a spacer is disposed and then the spacer is dispersed through the mask. It is shown. For example, Patent Document 2 discloses a method in which a spacer is electrostatically attracted to a photosensitive member and then transferred to a transparent substrate. Furthermore, Patent Document 3 discloses a method for manufacturing a liquid crystal display device in which a spacer is placed at a specific position by electrostatic repulsion by applying a voltage to pixel electrodes on a substrate and dispersing charged spacers. Has been.

However, in the methods described in Patent Documents 1 and 2, since the mask and the photoconductor are brought into direct contact with the substrate surface, the alignment film formed on the substrate surface may be damaged, and the image quality of the liquid crystal display device is deteriorated. There was something to do. On the other hand, in the method described in Patent Document 3, since it is necessary to configure the electrodes according to the spacer arrangement pattern, it is difficult to arrange the spacers at arbitrary positions.

On the other hand, Patent Document 4 discloses a method of arranging a spacer on a substrate using an ink jet apparatus. Since this method does not directly contact the mask or the photoconductor on the substrate, the alignment film formed on the substrate surface is not damaged, and the spacer can be arranged in a specific pattern at a specific position, which is effective. It can be said that it is a method.

However, in the method described in Patent Document 4, after a spacer having a particle diameter of about 1 to 10 μm is dispersed in a solvent or the like to form a spacer particle dispersion, the spacer particle dispersion is discharged from a nozzle of an inkjet device. Therefore, depending on the spacer particle dispersion, the spacer particle dispersion may not be discharged linearly from the nozzle. In addition, in order to discharge the spacer particle dispersion liquid linearly from the nozzle, it is necessary to increase the nozzle diameter. However, when the nozzle diameter is increased, the spacer particle dispersion liquid discharged onto the substrate Droplets also grow. When the droplet is large, for example, even when the droplet is ejected aiming at the non-pixel region, the droplet reaches the pixel region, and a spacer may be arranged in the pixel region. When the spacer is arranged in the pixel region, the contrast and color tone of the liquid crystal display device are lowered, and the display quality may be deteriorated.

Japanese Patent Laid-Open No. 4-198919 JP-A-6-258647 JP-A-10-339878 JP-A-57-58124

In view of the above-described situation, the present invention provides a method for manufacturing a liquid crystal display device, in which spacer particles can be arranged with high accuracy in a region corresponding to a non-pixel region on a substrate using an ink jet device, and the liquid crystal display device An object of the present invention is to provide a liquid crystal display device and a spacer particle dispersion obtained by the manufacturing method.

The present invention relates to a spacer particle dispersion that is discharged onto a substrate of a liquid crystal display element using an ink jet device and is used to dispose spacer particles on the substrate, and the spacer particle dispersion has a surface tension of 25 to 50 mN. In the spacer particle dispersion excluding the spacer particles, the solvent having a boiling point of 200 ° C. or more and a surface tension of 42 mN / m or more is 1% by weight or more, the boiling point is less than 150 ° C., and the surface This is a spacer particle dispersion containing 1.5 to 50% by weight of a solvent having a tension of less than 28 mN / m .
The present invention is described in detail below.

The present invention is a method of manufacturing a liquid crystal display device having a pixel region and a non-pixel region and having first and second substrates facing each other.
FIG. 1 is a partially cutaway front sectional view schematically showing a liquid crystal display device manufactured by the method for manufacturing a liquid crystal display device of the present invention.

In the liquid crystal display device 1 shown in FIG. 1, two second substrates 2 and a first substrate 3 are arranged so as to face each other.
Black matrices 4 are formed at equal intervals on the inner surface of the transparent substrate 2 </ b> A constituting the second substrate 2. On the black matrix 4 and on the inner surface of the transparent substrate 2 </ b> A between the black matrices 4, color filters 5 composed of three colors of red, green, and blue are formed to have a substantially constant thickness. An overcoat layer 6 is formed on the color filter 5 so as to have a flat surface. An ITO transparent electrode 7 having a substantially constant thickness is formed so as to cover the overcoat layer 6, and the alignment film 8 having a substantially constant thickness covers the ITO transparent electrode 7.

On the other hand, on the inner surface of the transparent substrate 3A constituting the first substrate 3, wirings 9 are formed at positions corresponding to the black matrix 3. An ITO transparent electrode 10 having a substantially constant thickness is formed on the inner surface of the transparent substrate 3A so that the wiring 9-9 is spaced apart from the wiring 9-9. An alignment film 11 having a substantially constant thickness is formed so as to cover the wiring 9 and the ITO transparent electrode 10. In the first substrate 3, the alignment film 11 has a raised portion 11 a in the portion where the wiring 9 is formed.

The 2nd board | substrate 2 and the 1st board | substrate 3 are joined via the sealing material which is not illustrated by each outer periphery vicinity. A liquid crystal 12 is sealed in a space surrounded by the second substrate 2 and the first substrate 3. A plurality of spacer particles 13 are arranged at a position corresponding to the black matrix 3, that is, a non-pixel region. Spaces between the first and second substrates 3 and 2 are regulated by the spacer particles 13 so that an appropriate liquid crystal layer thickness is maintained.

In the present invention, the substrate on which the spacer particles are arranged is referred to as a first substrate. When the spacer particles are arranged on the second substrate 2 described above, the second substrate is the first substrate. It becomes.

In the method for manufacturing a liquid crystal display device according to the present invention, a spacer particle dispersion liquid in which spacer particles are dispersed is discharged from a nozzle of an ink jet device onto the first substrate, and is applied to a non-pixel region on the first substrate. Disposing spacer particles in corresponding areas.

In this step, a spacer particle dispersion liquid in which spacer particles are dispersed is ejected from the nozzles of the ink jet apparatus onto the first substrate, and the spacer particles are applied to regions corresponding to non-pixel regions on the first substrate. The arrangement method will be described with reference to FIGS. FIGS. 2A to 2C show a process in which spacer particles are arranged in a stepwise front sectional view with partial cuts.

As shown in FIG. 2A, spacer particles including one or a plurality of spacer particles 13 so as to include a non-pixel region corresponding to the black matrix 4, that is, a raised portion 11 a of the alignment film 11 in the wiring 9 portion. Dispersion 13A is discharged. The discharged spacer particle dispersion 13A lands on a non-pixel area corresponding to the black matrix 4 as shown in FIG. Thereafter, the spacer particle dispersion 13A is dried, and as shown in FIG. 2 (c), the spacer particles 13 are formed in the non-pixel region corresponding to the black matrix 4, that is, in the protruding portion 11a of the alignment film 11 in the wiring 9 portion. It is arranged on the step surface. As shown in FIG. 2 (c), when a plurality of spacer particles 13 are included when the spacer particle dispersion 13A is dried, the spacer particles 13 are gathered toward the step surface of the raised portion 11a. It moves and is arranged so that the plurality of spacer particles 13 are in contact with each other.

As described above, the first substrate 3 is obtained in which one or a plurality of spacer particles 13 are respectively arranged in the non-pixel regions corresponding to the black matrix 4 as shown in the partially cutaway front sectional view of FIG. It is done. The first substrate 3 is superimposed on the second substrate 2 so as to face each other with the spacer particles 13 therebetween. Before the first and second substrates 3 and 2 are superimposed, the first substrate 3 or the second substrate 2 is injected between the superimposed first and second substrates 3 and 2. The liquid crystal 12 is disposed on the liquid crystal display device 1 shown in FIG.

(Spacer particles)
The material of the spacer particles used in the present invention is not particularly limited, and may be inorganic particles such as silica particles or organic particles such as organic polymers. Above all, it has an appropriate hardness that does not damage the alignment film formed on the substrate of the liquid crystal display device, easily follows changes in thickness due to thermal expansion and contraction, and spacer particles move inside the cell. Organic particles are preferably used because they are difficult to do.

Although it does not specifically limit as said organic type particle | grain, For example, since intensity | strength etc. are a moderate range, the copolymer of a monofunctional monomer and a polyfunctional monomer is used preferably.
The ratio of the monofunctional monomer and the polyfunctional monomer constituting the copolymer is not particularly limited, and can be appropriately adjusted depending on the strength and hardness required for the 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.

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 isomers, triallyl isocyanurate and its derivatives, trimethylolpropane tri (meth) acrylate and its derivatives, 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.

A monomer having a hydrophilic group may be used as the monofunctional monomer or polyfunctional monomer. 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.

Examples of the monomer having a hydrophilic group include 2-hydroxyethyl (meth) acrylate, 1,4-hydroxybutyl (meth) acrylate, (poly) caprolactone-modified hydroxyethyl (meth) acrylate, allyl alcohol, and glycerin monoallyl. Monomers having a hydroxyl group such as ether; acrylic acid such as (meth) acrylic acid, α-ethylacrylic acid, crotonic acid, and their α- or β-alkyl derivatives; fumaric acid, maleic acid, citraconic acid, Unsaturated dicarboxylic acids such as itaconic acid; monomers having a carboxyl group such as mono 2- (meth) acryloyloxyethyl ester derivatives of these unsaturated dicarboxylic acids; t-butylacrylamide sulfonic acid, styrenesulfonic acid, 2-acrylamide Sulfur such as 2-methylpropanesulfonic acid Monomers having a pyrrole 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 , (Poly) propylene glycol (meth) acrylate terminal alkyl ether, tetrahydrofurfuryl (meth) acrylate and other monomers having ether groups; (meth) acrylamide, methylol (meth) acrylami , And monomers having a amide group such as vinyl pyrrolidone.

The method for obtaining spacer particles by copolymerizing a monofunctional monomer and a polyfunctional monomer is not particularly limited, and examples thereof include various polymerization methods such as suspension polymerization method, seed polymerization method, and dispersion polymerization method. It is done.

In the suspension polymerization method, the obtained spacer particles have a wide particle size distribution, and polydisperse spacer particles can be obtained. By performing the classification operation of the spacer particles obtained by the suspension polymerization method, various spacer particles having a desired particle size and particle size distribution can be obtained. On the other hand, the seed polymerization method or the dispersion polymerization method is suitable for obtaining a large amount of spacer particles having a specific particle diameter because monodispersed spacer particles can be obtained without passing 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 in a poor solvent and polymerized so as to obtain a desired particle size. In the suspension polymerization method, a dispersion medium in which a dispersion stabilizer is added to water is usually used. Examples of the dispersion stabilizer include polymers that are soluble in the medium, and more specifically, for example, 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 in the range of 50 to 80 ° C., and the polymerization time is in the range of 3 to 24 hours.

The seed polymerization method is a polymerization method in which the monodispersed seed particles synthesized by soap-free polymerization or emulsion polymerization are further absorbed with a monomer to expand the seed particles to a desired particle diameter. It does not specifically limit as an organic monomer used for a seed particle, For example, the monomer mentioned above can be used. As the monomer adsorbed on the monodisperse seed particles, it is preferable to use a monomer having an affinity for the monodisperse seed particles in order to suppress phase separation during seed polymerization. As the monomer adsorbed on the monodisperse seed particles, styrene and its derivatives are more preferably used because the particle size distribution can be made more monodisperse.

Since the particle size distribution of the seed particles is reflected in the particle size distribution after seed polymerization, it is preferably monodispersed, and the Cv value is preferably 5% or less. As a monomer to be absorbed during seed polymerization, a monomer having a composition similar to that of seed particles is preferably used in order to prevent the phases from separating. When the seed particles are styrene-based particles, it is more preferable to use an aromatic divinyl monomer as a monomer to be absorbed during seed polymerization. When the seed particles are acrylic particles, it is more preferable to use an acrylic polyfunctional vinyl monomer as a monomer to be absorbed during seed polymerization.

In the seed polymerization method, a dispersion stabilizer is 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 and cause the adsorption.

The medium used for the seed polymerization is not particularly limited and may be appropriately changed depending on the monomer used. Generally, organic solvents that are preferably used include alcohols, cellosolves, ketones, and hydrocarbons. Can be mentioned. These media are used alone or mixed with other organic solvents compatible with them, water and the like. Specific examples of other organic solvents compatible with the medium include acetonitrile, N, N-dimethylformamide, dimethyl sulfoxide, ethyl acetate, methanol, ethanol, propanol and other alcohols, methyl cellosolve, ethyl Examples include cellosolves such as cellosolve, and ketones such as acetone, methyl ethyl ketone, methyl butyl ketone, and 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 a polymer dispersion stabilizer is added to this system to precipitate the particle-shaped generated polymer. Is the method.

In the dispersion polymerization method, when a crosslinking component is added, the particles are likely to aggregate and it is difficult to stably obtain monodispersed crosslinked particles. However, it is possible to obtain monodispersed crosslinked particles by adjusting the conditions. it can.

In the polymerization, a polymerization initiator is used. The polymerization initiator is not particularly limited. For example, benzoyl peroxide, lauroyl peroxide, benzoyl peroxide, benzoyl orthomethoxy peroxide, 3,5,5-trimethylhexanoyl peroxide, t-butylperoxy- Organic peroxides such as 2-ethylhexanoate and di-t-butyl peroxide, azo compounds such as azobisisobutyronitrile, azobiscyclohexacarbonitrile, azobis (2,4-dimethylvaleronitrile) Etc. are preferably used. The polymerization initiator is preferably added in the range of 0.1 to 10 parts by weight with respect to 100 parts by weight of the monomer used for the polymerization.

The particle diameter of the spacer particles is not particularly limited, and is appropriately changed depending on the type of the liquid crystal display element. The preferable lower limit of the particle diameter of the spacer particles is 1 μm, and the preferable upper limit is 20 μm. When the particle diameter is less than 1 μm, the spacer particles do not function sufficiently and the opposing substrates may come into contact with each other. When the particle diameter exceeds 20 μm, the spacer particles easily protrude from the non-pixel region or the like on the substrate. On the other hand, if the particle diameter is too large, the distance between the opposing substrates increases, and it is not possible to sufficiently meet the recent demands for downsizing liquid crystal display elements.

The spacer particles are used as a gap material for maintaining an appropriate liquid crystal layer thickness. Therefore, the spacer particles are required to have a certain strength. As an index indicating the compressive strength of the spacer particles, a compressive elastic modulus (10% K value) when the spacer particles are displaced by 10% is used. In order to maintain an appropriate thickness of the liquid crystal layer, the preferable lower limit of the compressive elastic modulus is 2000 MPa, and the preferable upper limit is 15000 MPa. If the compression modulus is less than 2000 MPa, the spacer particles may be deformed by the press pressure when assembling the liquid crystal display element, and it may be difficult to obtain a desired thickness of the liquid crystal layer. If the compression modulus is greater than 15000 MPa, the alignment film formed on the substrate surface may be damaged when spacer particles are arranged in the liquid crystal display element.

The compression elastic modulus (10% K value) of the spacer particles is determined according to the method described in JP-T-6-503180. For example, using a micro-compression tester (for example, “PCT-200” manufactured by Shimadzu Corporation), the particle is a smooth indenter end face made of a diamond cylinder having a diameter of 50 μm, a compression speed of 2.6 mN / sec, and a maximum test load of 10 g. The compression displacement (mm) when the substrate particles are compressed under the conditions can be measured and determined by the following formula.
K value (N / mm ² ) = (3/2 ^1/2 ) · F · S ⁻³ / ² · R ^−1/2
F: Load value (N) at 10% compression deformation of the base particle
S: Compression displacement (mm) in 10% compression deformation of substrate particles
R: radius of base particle (mm)

In order to obtain spacer particles having a 10% K value satisfying the above conditions, the spacer particles are preferably made of a resin obtained by polymerizing a monofunctional or polyfunctional monomer having an ethylenically unsaturated group. More preferably, the composition contains at least 20% by weight of a polyfunctional monomer.

The spacer particles preferably have a lower recovery rate of 20%. If it is less than 20%, even if the spacer particles are compressed, they do not return to their original shape even if they are deformed. A more preferred lower limit is 40%. In addition, the said recovery rate means the recovery rate after applying a load of 9.8 mN to the spacer particles.

In order to improve the contrast of the liquid crystal display element, the spacer particles may be colored and used. As the colored spacer particles, for example, spacer particles treated with carbon black, disperse dyes, acid dyes, basic dyes, metal oxides, or the like, or after an organic film is formed on the surface of the spacer particles, the temperature is increased. And spacer particles colored by being decomposed or carbonized in FIG. In addition, when the material itself which comprises spacer particle | grains is colored, you may use without coloring spacer particle | grains.

The spacer particles may be subjected to a chargeable process. The chargeable process is a process in which the spacer particles have some potential in the spacer particle dispersion. The potential (charge) of the spacer particles is measured by an existing measuring method using an existing measuring device such as a zeta potential measuring device.

Examples of a method for performing chargeable treatment include a method in which a charge control agent is contained in the spacer particles, a method in which spacer particles are produced using a monomer containing a monomer component that is easily charged, and the spacer particles are charged. Examples include a method of performing a possible surface treatment.

When the spacer particles can be charged, the dispersibility and dispersion stability of the spacer particles in the spacer particle dispersion can be improved. Therefore, when the spacer particles are dispersed, the spacer particles are likely to gather near the wiring portion (step) due to the electrophoretic effect.

As a method of containing the charge control agent, when obtaining spacer particles, a method of performing polymerization in the presence of a charge control agent, a charge control agent having a functional group copolymerizable with the monomer constituting the spacer particles, Copolymerization by coexisting with the monomer constituting the spacer particle, and the charge control agent having a functional group copolymerizable with the monomer used for the surface modification in the surface modification of the spacer particle described later. And a method in which charged particles having a functional group opposite to the surface functional group of the surface modification layer or spacer particle are reacted with the surface of the spacer particle.

Although it does not specifically limit as said charge control agent, For example, the charge control agent of Unexamined-Japanese-Patent No. 2002-148865 can be used. Although it does not specifically limit as a charge control agent, An organometallic compound, a chelate compound, a monoazo dye metal compound, an acetylacetone metal compound, an aromatic hydroxyl carboxylic acid, an aromatic mono- and polycarboxylic acid and its metal salt, an anhydride, ester And phenol derivatives such as bisphenol.

Specific examples of the charge control agent include urea derivatives, metal-containing salicylic acid compounds, quaternary ammonium salts, calixarene, silicon compounds, styrene-acrylic acid copolymers, styrene-methacrylic acid copolymers, and styrene. -Acrylic-sulfonic acid copolymer, non-metal carboxylic acid compound, modified product with nigrosine and fatty acid metal salt, 4 such as tributylbenzylammonium-1-hydroxy-4-naphthosulfonate, tetrabutylammonium tetrafluoroborate Quaternary ammonium salts and onium salts such as phosphonium salts and analogs thereof and lake pigments thereof, triphenylmethane dyes and lake pigments thereof, metal salts of higher fatty acids, dibutyltin oxide, dioctyltin oxide, dicyclohexyltin oxide Diorganotin oxide such as id, dibutyltin tin borate, dioctyl tin borate, diorgano tin borate, and the like, such as dicyclohexyl tin borate, and the like. Examples of the lake agent used in the lake pigment include phosphotungstic acid, phosphomolybdic acid, phosphotungstic molybdic acid, tannic acid, lauric acid, gallic acid, ferricyanide, ferrocyanide, and the like. These charge control agents may be used alone or in combination of two or more.

The polarity of the spacer particles containing the charge control agent can be set by appropriately selecting the charge control agent. That is, the spacer particles can be positively charged or negatively charged depending on the surrounding environment.

Examples of a method for producing spacer particles using a monomer containing a monomer component that is easily charged include a method in which a monomer having a hydrophilic functional group is used in combination among the monomers described above. It is done. Depending on the surrounding environment, spacer particles can be positively charged or negatively charged by appropriately selecting and using appropriate monomers from these monomers having hydrophilic functional groups. be able to.

As a method for performing a surface treatment capable of charging the spacer particles, for example, as described in JP-A-1-247154, a method of depositing a resin on the surface of spacer particles for modification, JP-A-9-113915 Alternatively, as described in JP-A-7-300587, a method in which a compound that reacts with a functional group on the surface of the spacer particle is allowed to act on the surface of the spacer particle, JP-A-11-223821 or JP-A-2003-295198 is used. As described in the publication, there are a method of modifying the surface by graft polymerization on the surface of the spacer particles, a method of forming a surface layer chemically bonded to the surface of the spacer particles, and the like. In performing these surface treatments, an appropriate method is selected so that the spacer particles are charged.

As a method of performing a surface treatment capable of charging the spacer particles, a surface layer chemically bonded to the surface of the spacer particles in order to prevent the surface layer from peeling off and eluting into the liquid crystal in the cell of the liquid crystal display device. The method of forming is preferred.

As described above, the adhesion of the spacer particles to the substrate can be enhanced by subjecting the spacer particles to a surface treatment. In addition, by appropriately selecting the monomers constituting the spacer particles, it is possible to suppress the disorder of the alignment of the liquid crystal in the liquid crystal display element.

(Spacer particle dispersion)
By dispersing the above-described spacer particles in a medium in which the spacer particles can be dispersed, a spacer particle dispersion can be obtained.

In the method for producing a liquid crystal display device of the present invention, the spacer particle dispersion contains at least a solvent X having a boiling point of 200 ° C. or higher and a surface tension at 20 ° C. of 42 mN / m or higher as a medium. In the present specification, “boiling point” refers to the boiling point under 1 atm.

The mixing ratio of the solvent X in the spacer particle dispersion is such that the lower limit of the amount of the solvent X contained in the spacer particle dispersion discharged at one time from one nozzle of the inkjet device described later is 0.5 ng, and the upper limit is It is adjusted to be 15 ng.

In the case where the amount of the solvent X discharged at one time is less than 0.5 ng, the spacer particles are dispersed when the spacer particle dispersion is dried after the spacer particle dispersion is discharged onto the substrate. The spacer particles are not easily gathered, and the spacer particles are easily arranged in the region corresponding to the non-pixel region. When the amount of the solvent X discharged at one time is blended so as to be more than 15 ng, after the spacer particle dispersion is discharged onto the substrate, when the spacer particle dispersion is dried, for example, 70 ° C. It is necessary to dry under the above high temperature, or to dry over a long time at the temperature below 70 degreeC. When drying at a high temperature of 70 ° C. or higher, the alignment film is easily damaged. When drying at a temperature lower than 70 ° C. for a long time, for example, the drying takes 10 minutes or more and the production efficiency is high. Deteriorate.

The solvent X is preferably contained in an amount of 1% by weight or more in the spacer particle dispersion excluding the spacer particles. If the solvent X is less than 1% by weight, the spacer particle dispersion may not be stably ejected from the nozzles of an ink jet apparatus described later, or the spacer particles may be difficult to gather. When drying under normal pressure, a more preferred lower limit is 5% by weight, a more preferred upper limit is 60% by weight, a still more preferred lower limit is 10% by weight, and a still more preferred upper limit is 40% by weight. When the area of the non-pixel region on the substrate is small and it is desired to reduce the discharge area of the spacer particle dispersion, the preferable lower limit of the amount of the solvent X is 70% by weight, and the preferable upper limit is 90% by weight. Further, when the spacer particles are likely to settle in the spacer dispersion, the lower limit of the content ratio of the solvent X is more preferably 80% by weight and the upper limit is preferably 100% by weight.
Here, a spacer particle dispersion containing 1% by weight or more of the solvent X, that is, spacer particles which are ejected onto a substrate of a liquid crystal display element using an ink jet apparatus and used to dispose the spacer particles on the substrate. A dispersion having at least a solvent having a boiling point of 200 ° C. or more and a surface tension of 42 mN / m or more, the solvent having a boiling point of 200 ° C. or more and a surface tension of 42 mN / m or more is 1 A spacer particle dispersion containing not less than wt% is also one aspect of the present invention.

When the boiling point of the solvent X is less than 200 ° C., the spacer particle dispersion is easily dried at the tip of the nozzle of the ink jet apparatus described later, and the nozzle is easily clogged. In the spacer particle dispersion containing only the solvent having a boiling point of less than 180 ° C., nozzle clogging is more likely to occur. Moreover, since the solvent whose boiling point is less than 200 degreeC has a low viscosity and specific gravity, when the solvent whose boiling point is 200 degreeC or more is not included, it is difficult to make the viscosity of a spacer particle dispersion into an appropriate range. Further, in the spacer particle dispersion containing only the solvent having a boiling point of less than 200 ° C., the spacer particles are likely to settle.

When the surface tension of the solvent X is less than 42 mN / m, after the spacer particle dispersion is discharged onto the substrate, the spacer particles do not gather when the spacer particle dispersion is dried, and the spacer particles do not gather in the non-pixel region. It becomes easy to arrange.

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. As the solvent X, the above-described solvents may be used alone, or two or more kinds may be used in combination.

In the spacer particle dispersion liquid, in addition to the solvent X, for example, various solvents that are liquid at a temperature discharged from a nozzle may be included. Of these, a water-soluble or hydrophilic solvent is preferable. A nozzle for an aqueous medium may be used in an ink jet apparatus. When a nozzle for an aqueous medium is used, if a highly hydrophobic solvent is used as the medium for the spacer particle dispersion liquid, the solvent penetrates into the member constituting the nozzle or the adhesive that adheres the member. Some may dissolve in the solvent. Therefore, when a nozzle for an aqueous medium is used, it is preferable that the spacer particle dispersion contains a water-soluble or hydrophilic solvent.

Examples of the water-soluble or hydrophilic solvent include water, ethanol, n-propanol, 2-propanol, 1-butanol, 2-butanol, 1-hexanol, 1-methoxy-2-propanol, furfuryl alcohol, tetrahydro Monoalcohols such as furfuryl alcohol, multimers of ethylene glycol such as ethylene glycol, diethylene glycol, triethylene glycol, and tetraethylene glycol; multimers of propylene glycol such as propylene glycol, dipropylene glycol, tripropylene glycol, and tetrapropylene glycol Lower monoalkyl ethers of glycols such as monomethyl ether, monoethyl ether, monoisopropyl ether, monopropyl ether, monobutyl ether; Lower dialkyl ethers such as ter, diethyl ether, diisopropyl ether and dipropyl ether; alkyl esters such as monoacetate and diacetate, 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- Diols such as pentanediol, 2,5-hexanediol, 1,6-hexanediol, neopentylglycol, ether derivatives of diols, acetate derivatives of diols, glycerin, 1,2,4-butanetriol, 1, 2,6-hexanetriol, 1,2,5-pentanetriol, tri Polyhydric alcohols such as tyrolpropane, trimethylolethane, pentaerythritol or ether derivatives thereof, acetate derivatives, 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 Bis-β-hydroxyethyl sulfone, bis-β-hydroxyethyl urea, N, N-diethylethanolamine, abiethinol, diacetone alcohol, urea and the like.

The spacer particle dispersion preferably contains a solvent having a boiling point of 150 ° C. or higher. Furthermore, it is more preferable to include a solvent having a boiling point of 150 ° C. or higher and a surface tension of 30 mN / m or higher. When a solvent having a boiling point of 150 ° C. or higher and a surface tension of 30 mN / m or higher is included, the receding contact angle (θr) described later can be increased. In addition, if a solvent having a boiling point of 150 ° C. or higher and a surface tension of 30 mN / m or higher is included, the droplet diameter when the spacer particle dispersion is discharged and landed on the substrate is reduced, so that the droplet spreads. Is unlikely to occur. Furthermore, the spacer particles can easily move toward the landing center of the droplet. Therefore, the spacer particles can be arranged on the substrate with high accuracy.

A preferable lower limit of the surface tension of the spacer particle dispersion is 25 mN / m, and a preferable upper limit is 50 mN / m. When the surface tension of the spacer particle dispersion is lower than 25 mN / m, the droplet diameter may be too large when the spacer particle dispersion is discharged and landed on the substrate, and the nozzle surface of the head of the inkjet apparatus May become wet and the discharge state may become unstable. If it exceeds 50 mN / m, when the head is filled with the spacer dispersion liquid, there may be a problem that bubbles are likely to remain in the ink chamber in the head of the ink jet apparatus and cannot be discharged. However, 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 (for example, SUS, ceramic, glass, etc.) and / or before filling with the spacer dispersion liquid, 2- If the surface of the flow path and head can be replaced with a spacer dispersion liquid after filling the ink chamber with a solvent that has a low surface tension, such as propanol, and thoroughly removing the bubbles, and then avoiding the inclusion of bubbles. Although it takes time for equipment and processes, even a spacer dispersion liquid exceeding 50 mN / m can be discharged.
The surface tension of the spacer particle dispersion is adjusted by appropriately combining the solvents described above.

In order to set the surface tension of the spacer particle dispersion to 50 mN / m or less, it is more preferable that the solvent of the spacer particle dispersion further includes a solvent having a boiling point of less than 150 ° C. in addition to the solvent X and the like. More preferably, it contains a solvent having a boiling point of 70 ° C or higher and lower than 100 ° C.

Examples of the solvent having a boiling point of less than 150 ° C. include lower monoalcohols such as ethanol, n-propanol, 2-propanol, 1-butanol, 2-butanol, and tert-butanol, and acetone. These may be used alone or in combination of two or more. Of these, 2-propanol is most preferred.

The solvent having a boiling point of less than 150 ° C. volatilizes at a relatively low temperature when the spacer dispersion liquid is discharged onto the substrate and then dried. In particular, in the spacer dispersion liquid, when the solvent contacts the alignment film at a high temperature, the alignment film is contaminated and the display quality of the liquid crystal display device is impaired. Therefore, the drying temperature cannot be increased too much. Therefore, it is preferable to use a solvent having a boiling point of less than 150 ° C. However, if the solvent having a boiling point of less than 150 ° C. is likely to evaporate at room temperature, aggregated particles are likely to be generated during the production or storage of the spacer dispersion, and the spacer dispersion near the nozzles of the inkjet device is likely to be dried. Thus, since the inkjet dischargeability is impaired, a solvent that easily volatilizes at room temperature is not preferable.

If the temperature at which the spacer particle dispersion discharged on the substrate is dried is high, the alignment film may be damaged and the display image quality of the liquid crystal display device may be deteriorated. However, a solvent having a boiling point of less than 150 ° C. is used. By doing so, the drying temperature can be lowered and the alignment film can be prevented from being damaged.

The preferable lower limit of the content of the solvent having a boiling point of less than 150 ° C. is 1.5 parts by weight and the preferable upper limit is 50 parts by weight with respect to 100 parts by weight of the spacer particle dispersion excluding the spacer particles. If it is less than 1.5 parts by weight, the drying rate may be slow, and the production efficiency of the liquid crystal display device may be reduced. When the amount exceeds 50 parts by weight, the spacer particle dispersion is easily dried at the tip of the nozzle of the ink jet apparatus. Further, when the spacer particle dispersion is manufactured or the spacer particle dispersion is stored, the spacer particle dispersion is dispersed. The liquid may dry and the spacer particles may agglomerate.

The solvent having a boiling point of less than 150 ° C. preferably has a surface tension at 20 ° C. of less than 28 mN / m, more preferably 25 mN / m or less. When the surface tension of the solvent is 28 mN / m or more, the surface tension of the spacer particle dispersion increases, and depending on the surface tension of the liquid contact portion of the nozzle of the ink jet apparatus, the discharge performance may be deteriorated.

When the spacer particle dispersion liquid contains a solvent having a boiling point of less than 150 ° C. and a surface tension of less than 28 mN / m, the spacer particle dispersion liquid can be easily introduced into an ink jet apparatus described later, and the discharge property is improved when discharging. To do.

When the spacer particle dispersion is dried, the solvent having a low boiling point is volatilized first. When the solvent having a low boiling point volatilizes first, the ratio of the solvent X in the remaining spacer particle dispersion increases. When the ratio of the solvent X is increased, the surface tension of the remaining spacer particle dispersion is further increased, and the spacer particles are easily moved toward the landing point center.

The preferred lower limit of the viscosity at 20 ° C. of the spacer particle dispersion is greater than 5 mPa · s, and the preferred upper limit is preferably less than 20 mPa · s. When the viscosity is 5 mPa · s or less, the spacer particles dispersed in the spacer particle dispersion liquid are likely to settle over time. When the viscosity is 20 mPa · s or more, it may be difficult to control the discharge amount when the spacer particle dispersion is discharged from the nozzle. In order to control the discharge properties, it may be necessary to warm the spacer particle dispersion excessively.

The preferable lower limit of the specific gravity at 20 ° C. of the spacer particle dispersion is 1.00 g / cm ³ . If it is less than 1.00 g / cm ³ , the spacer particles dispersed in the spacer particle dispersion liquid easily settle out over time.

A preferable lower limit of the sedimentation rate of the spacer particle dispersion is 150 minutes or more. The above settling velocity means that when a spacer particle dispersion 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 standing, the deposition of spacer particles is visually confirmed on the bottom of the test tube. Of time.

When the settling speed of the spacer particle dispersion is 150 minutes or more, it is difficult for the spacer particles to settle after the spacer particle dispersion is introduced into the ink jet apparatus and before the spacer particle dispersion is discharged. Therefore, it is possible to stably discharge the spacer particle dispersion using the ink jet apparatus.

When discharged onto the substrate, the receding contact angle (θr) of the spacer particle dispersion with respect to the substrate is preferably 5 degrees or more. When the receding contact angle is 5 degrees or more, when the spacer particle dispersion discharged onto the substrate is dried, the droplets are easily reduced toward the landing center of the spacer particle dispersion. Further, even when a plurality of spacer particles are included in one droplet, the spacer particles tend to gather toward the landing center.

The receding contact angle is a process in which the spacer particle dispersion discharged on the substrate lands on the substrate and then dries, and when the landing diameter of the spacer particle dispersion that has landed on the substrate starts to decrease, That is, the contact angle when the droplet starts to shrink or the contact angle when 80 to 95% by weight of the volatile component of the droplet is volatilized.

Examples of the method of setting the receding contact angle to 5 degrees or more include a method of adjusting the solvent composition of the spacer particle dispersion described above, a method of surface-treating the substrate, and the like.

When adjusting the composition of the solvent of the spacer particle dispersion, a solvent having a receding contact angle of 5 degrees or more may be used alone, or two or more kinds of solvents may be used in combination. When two or more solvents are mixed and used, the dispersibility of the spacer particles, the workability when using the spacer particle dispersion, the drying speed of the spacer particle dispersion, and the like can be easily adjusted.

When the two or more solvents are mixed and used, the receding contact angle of the solvent having the highest boiling point among the mixed solvents is preferably 5 degrees or more. When the receding contact angle of the solvent having the highest boiling point is less than 5 degrees, the solvent having the highest boiling point remains in the drying process. In this case, the droplet diameter of the spacer particle dispersion becomes large, and on the substrate. Droplets are easy to spread. In addition, the spacer particles tend to gather toward the landing center.

The receding contact angle tends to be smaller than the initial contact angle immediately after the spacer particle dispersion has landed on the substrate. At the initial contact angle, the solvent constituting the spacer particle dispersion is not sufficiently in contact with the substrate surface, but at the receding contact angle, the solvent is sufficiently in contact with the substrate surface. When the receding contact angle is significantly lower than the initial contact angle, the alignment film may be damaged by the solvent.

The preferable lower limit of the initial contact angle of the spacer dispersion liquid with respect to the substrate is 10 degrees, and the preferable upper limit is 110 degrees. If it is less than 10 degrees, the spacer particle dispersion liquid discharged on the substrate spreads on the substrate, and the arrangement interval of the spacer particles may increase. If the initial contact angle is larger than 110 degrees, the droplets are likely to move on the substrate, and the placement accuracy may be lowered, or the adhesion between the spacer particles and the substrate may be deteriorated.

The preferable lower limit of the viscosity of the spacer particle dispersion when discharged from the nozzle of the ink jet apparatus is 0.5 mPa · s, and the preferable upper limit is 15 mPa · s. When the viscosity of the spacer particle dispersion when discharged is less than 0.5 mPa · s, it may be difficult to control the discharge amount, and when it exceeds 15 mPa · s, it may be difficult to discharge. . A more preferred lower limit is 5 mPa · s, and a more preferred upper limit is 10 mPa · s.
Further, when discharging the spacer particle dispersion, the temperature of the spacer particle dispersion at the time of discharge is reduced by cooling the nozzle of the ink jet apparatus using a Peltier element or a refrigerant, or by heating with a heater or the like. Is preferably adjusted in the range of −5 ° C. to 50 ° C.

The preferable lower limit of the solid content concentration of the spacer particles in the spacer particle dispersion is 0.01% by weight, and the preferable upper limit is 5% by weight. When the amount is less than 0.01% by weight, spacer particles may not be included in the discharged droplets. When the amount exceeds 5% by weight, the nozzles of the inkjet device are likely to be clogged, and the discharged liquid The number of spacer particles contained in the droplet is too large, making it difficult for the spacer particles to move during the drying process. A more preferred lower limit is 0.2% by weight, and a more preferred upper limit is 2% by weight.
The solid content concentration of the spacer particles in the spacer particle dispersion is appropriately set depending on the number of spacer particles arranged on the substrate.

The spacer particles are preferably dispersed in the form of single particles in the spacer particle dispersion. If aggregated spacer particles are present in the spacer particle dispersion, the discharge accuracy may be reduced and the nozzles of the ink jet apparatus may be clogged.

In the present invention, an adhesive component for imparting adhesiveness may be added to the spacer particle dispersion as long as the effects of the present invention are not impaired. Furthermore, in order to increase the dispersibility of the spacer particles, control the physical properties such as surface tension and viscosity to increase the discharge accuracy, and improve the movement performance of the spacer particles during drying, various surfactants, A viscosity modifier or the like may be added to the spacer particle dispersion.

Here, the spacer particle dispersion liquid contains the above-mentioned solvent, and the composition of the solvent can be adjusted by appropriately combining in accordance with the state of the ink chamber in the head of the inkjet device described later. preferable.

Further, the spacer particle dispersion contains the solvent X described above as a solvent as described above. When spacer particles are gathered even on a substrate having a high surface tension, a preferable combination of the solvents is, for example, A solvent having a boiling point of less than 150 ° C. and a surface tension of less than 28 mN / m has a preferred lower limit of 2% by weight, a preferred upper limit of 40% by weight (a further preferred lower limit is 5% by weight, and a more preferred upper limit is 20% by weight). A solvent having a surface tension of 30 mN / m or more is preferably 0% by weight, a preferred upper limit is 95% by weight (a further preferred lower limit is 40% by weight, a further preferred upper limit is 90% by weight), and the solvent X However, the preferred lower limit is 1% by weight, the preferred upper limit is 96% by weight (the more preferred lower limit is 3% by weight, the more preferred upper limit is 40% by weight), and water is preferred. The lower limit is 0% by weight and the desirable upper limit is 60 wt% (more preferred lower limit is 5% by weight, still more preferred upper limit 40% by weight), and the combination of. More preferably, the ratio of the solvent having the boiling point of 150 ° C. or more and the surface tension of 30 mN / m or more and the solvent X is 30 to 96% by weight (more preferably 40 to 90% by weight), and the boiling point is Is less than 150 ° C., and the ratio of the solvent having a surface tension of less than 28 mN / m and water is 4 to 70% by weight (more preferably 6 to 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 is less than 2% by weight, the surface tension of the spacer particle dispersion becomes too high, and the ink is introduced when the spacer particle dispersion is introduced into the head. There is a high probability that bubbles will remain in the chamber, causing a problem of nozzles that do not discharge. If it exceeds 40% by weight, the surface tension of the spacer particle dispersion becomes too low, and when the spacer particle dispersion is discharged onto the substrate, the landing diameter of the droplets that have landed on the substrate becomes large, and the spacer particles are on the substrate. There are problems that make it difficult to get together.
Further, if the amount of water and a solvent having a boiling point of less than 150 ° C. and a surface tension of less than 28 mN / m is less than 4% by weight, the spacer particle dispersion is too viscous to be ejected from the inkjet head. (When the driving voltage becomes too high), the viscosity of the spacer particle dispersion becomes too low, and the discharge stability, particularly the stability in the high frequency driving state is low. Problems may occur.
If the solvent X is less than 1% by weight, there is a problem that the spacer particles are difficult to gather on the substrate having a high surface tension. If the solvent X exceeds 96% by weight, the spacer particle dispersion liquid droplets landed on the substrate. There is a problem that it takes a long time to dry the film, resulting in a decrease in productivity, or a problem that the alignment film needs to be heated at a high temperature and the alignment film is likely to be damaged.

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 before filling with the spacer particle dispersion liquid. When the surface of the flow path and the head can be replaced with the spacer particle dispersion liquid after the bubbles are sufficiently removed after filling with a solvent having a low surface tension, such as 2-propanol, which sufficiently wets the ink chamber. As a preferable combination of the above solvents, for example, a solvent having a boiling point of less than 150 ° C. and a surface tension of less than 28 mN / m is preferably blended at less than 2% by weight, and the boiling point of 150 ° C. or more and the surface tension is preferably A lower limit of a solvent of 30 mN / m or more is preferably 0% by weight, and a preferable upper limit is 95% by weight (a more preferable lower limit is 40% by weight, and a more preferable upper limit is 90% by weight. The lower limit of the solvent X is preferably 1% by weight, the preferable upper limit is 96% by weight (the more preferable lower limit is 3% by weight, and the more preferable upper limit is 40% by weight), A combination with 70% by weight (more preferable lower limit is 6% by weight, and further preferable upper limit is 55% by weight).
More preferably, the ratio of the solvent X and the solvent having a boiling point of 150 ° C. or higher and a surface tension of 30 mN / m or higher is 30 to 96% (more preferably 40 to 90% by weight), and the boiling point is The ratio of a solvent having a surface tension of less than 150 ° C. and a surface tension of less than 28 mN / m and water is 4 to 70% by weight (more preferably 6 to 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 is too high, making it difficult to eject from the inkjet head (driving voltage becomes too high). In some cases, if it exceeds 70% by weight, the viscosity of the spacer particle dispersion becomes too low, which may cause a problem that the discharge stability, particularly the stability in a high frequency driving state, is lowered.
If the solvent X is less than 1% by weight, there is a problem that the spacer particles are difficult to gather on the substrate having a high surface tension. If the solvent X exceeds 96% by weight, the spacer particle dispersion liquid droplets landed on the substrate. There is a problem that it takes a long time to dry the film, resulting in a decrease in productivity, or a problem that the alignment film needs to be heated at a high temperature and the alignment film is likely to be damaged.

Moreover, it is preferable that the said spacer particle dispersion liquid contains an adhesive agent.
The adhesive exhibits a bonding force in the process of drying the spacer particle dispersion liquid landed on the substrate, and has a role of firmly fixing the spacer particles to the substrate. When the spacer dispersion liquid contains the adhesive, in addition to the above-described effect of collecting the spacer particles effectively in a short time during drying, the arranged spacer particles can be firmly fixed to the substrate.
The adhesive may be dissolved or dispersed in the spacer particle dispersion. When the adhesive is dispersed, the dispersion diameter is preferably 10% or less of the particle diameter of the spacer particles.

The adhesive is preferably very flexible, that is, has a lower elastic modulus (after curing) than the spacer particles so as not to impair the gap retention capability of the spacer particles.
Examples of the adhesive include thermoplastic resins having a glass transition point of 150 ° C. or lower; resins that are solidified by the diffusion of solvent; curable resins such as thermosetting resins, photocurable resins, and photothermosetting resins. It is done. Of these adhesives, those having a low molecular weight are preferably used.

The thermoplastic resin having a glass transition point of 150 ° C. or lower can be melted or softened by heat at the time of thermocompression bonding of the substrate to exert an adhesive force and firmly fix the spacer particles to the substrate.
The thermoplastic resin having a glass transition point of 150 ° C. or lower is preferably one that does not dissolve in the alignment film solvent, and preferably one that does not dissolve the alignment film. When a thermoplastic resin that dissolves in the alignment film solvent or dissolves the alignment film is used, it may cause liquid crystal contamination.

The glass transition point is 150 ° C. or lower, and is not particularly limited as a thermoplastic resin that does not dissolve in the alignment film solvent or does not dissolve the alignment film. For example, poly (meth) acrylic resin, polyurethane resin, Polyester resins, epoxy resins, polyamide resins, polyimide resins, cellulose resins; polyolefin resins such as polybutadiene and polybutylene; polyvinyl resins such as polyvinyl chloride, polyvinyl acetate, and polystyrene; polyacrylic resins, polycarbonate resins, and polyacetal resins. . Moreover, in a copolymer such as styrene-butadiene-styrene resin, one having a glass transition point of 150 ° C. or lower by adjusting a monomer component can be used.

The resin that cures by volatilization of the solvent in the spacer particle dispersion is in an uncured state while blended in the spacer particle dispersion, and the solvent volatilizes after the spacer particle dispersion is discharged onto the substrate. It can harden | cure and can fix a spacer particle | grain firmly to a board | substrate.
Examples of such a resin include an acrylic adhesive using a blocked isocyanate when the solvent is aqueous. Of these, those which are water-soluble and can be crosslinked are preferred.

The curable resin such as the thermosetting resin, the photocurable resin, and the photothermosetting resin is not cured while being mixed in the spacer particle dispersion, and after discharging the spacer particle dispersion to the substrate, It is hardened by heating and / or light irradiation, and the spacer particles can be firmly fixed to the substrate.
The thermosetting resin is not particularly limited, and examples thereof include a phenol resin, a melamine resin, an unsaturated polyester resin, an epoxy resin, and a maleimide resin. In addition, alkoxymethylacrylamide or the like that starts the reaction by heating; a resin having a reactive functional group that causes a crosslinking reaction (urethane reaction, epoxy crosslinking reaction, etc.) to occur by mixing a crosslinking agent in advance and heating; heating It is also possible to use a monomer mixture (for example, a mixture of an oligomer having an epoxy group in the side chain and an initiator) that reacts with the above to form a crosslinkable polymer.
The photo-curing resin is not particularly limited. For example, a mixture of an initiator that initiates reaction by light and various monomers (for example, a photo radical initiator and an acrylic monomer-binder mixture; photo acid generation) Initiator and epoxy oligomer mixture, etc.); polymers having reactive groups that are cross-linked by light (such as citrate compounds); azide compounds and the like.

In the spacer particle dispersion, the adhesive has a structural unit represented by the following general formula (1) and a structural unit represented by the following general formula (2), and the following general formula (1 A copolymer (A) in which the content of the structural unit represented by 5) to 90 mol% and the content of the structural unit represented by the following general formula (2) is 10 to 95 mol%; A mixture with at least one polyvalent compound (B) selected from the group consisting of carboxylic acid anhydrides, polyvalent carboxylic acids, aromatic polyvalent phenols and aromatic polyvalent amines is preferred. Hereinafter, the adhesive component which is a mixture of the copolymer (A) and the polyvalent compound (B) is also referred to as “adhesive composed of a mixture”.

In the formula, R ¹ and R ³ each represent a hydrogen atom or a methyl group, R ² represents an alkyl group having 1 to 8 carbon atoms, and R ⁴ represents an alkyl group having 1 to 12 carbon atoms or 5 carbon atoms. Represents a cycloalkyl group of 12 or an aromatic group. The cycloalkyl group and aromatic group may have a substituent.

When the adhesive is an adhesive made of the mixture, the spacer particle dispersion does not cause gelation due to the progress of a crosslinking reaction as seen in a normal acid-epoxy copolymer, and is an adhesive made of the mixture. It becomes possible to increase the epoxy group content of the agent. Further, since the spacer particle dispersion liquid containing the adhesive composed of the above mixture can achieve a high concentration and low viscosity, it is possible to disperse the spacer particles by an ink jet apparatus, and on the substrate together with the spacer particles. The adhesive composed of the above mixture dispersed on the surface has a high ability to fix the spacer particles on the substrate, and further, after curing, a high crosslink density is obtained, thus forming a gap retaining material excellent in various resistances. Can do. Moreover, heat resistance can also be improved. That is, by containing an adhesive composed of the above mixture as an adhesive, a spacer dispersion liquid droplet is ejected by using an ink jet device to land on a predetermined position on a substrate, and then dried to form spacer particles. Can be accurately and firmly disposed at a predetermined position on the substrate.

The copolymer (A) contained in the adhesive composed of the mixture is represented by the structural unit represented by the general formula (1) (hereinafter also referred to as the structural unit (a1)) and the general formula (2). Structural unit (hereinafter also referred to as structural unit (a2)).

As a monomer used as the said structural unit (a1), the radically polymerizable compound which has an epoxy group is mentioned, for example.
The radical polymerizable compound having an epoxy group is not particularly limited. For example, glycidyl acrylate, glycidyl methacrylate, glycidyl α-ethyl acrylate, glycidyl α-n-propyl acrylate, glycidyl α-n-butyl acrylate , Acrylic acid-3,4-epoxybutyl, methacrylic acid-3,4-epoxybutyl, acrylic acid-6,7-epoxyheptyl, methacrylic acid-6,7-epoxyheptyl, α-ethylacrylic acid-6,7 -Epoxy heptyl etc. are mentioned. Of these, glycidyl acrylate and glycidyl methacrylate are preferably used. These may be used independently and 2 or more types may be used together.

In the copolymer (A), the lower limit of the content of the structural unit (a1) is 5 mol%, and the upper limit is 90 mol%. If it is less than 5 mol%, the heat resistance and chemical resistance of the adhesive composed of the above mixture will decrease, and if it exceeds 90 mol%, the spacer particle dispersion containing the adhesive composed of the above mixture will gel. End up. A preferred lower limit is 10 mol%, and a preferred upper limit is 70 mol%.

As a monomer used as the said structural unit (a2), a monoolefin type unsaturated compound is mentioned, for example.
The monoolefin unsaturated compound is not particularly limited. For example, alkyl methacrylate such as methyl methacrylate, ethyl methacrylate, n-butyl methacrylate, sec-butyl methacrylate, t-butyl methacrylate; methyl acrylate, n-butyl acrylate Acrylic acid alkyl esters such as isopropyl acrylate; cyclic alkyl esters of methacrylic acid such as cyclohexyl methacrylate, 2-methylcyclohexyl methacrylate, dicyclopentanyloxyethyl methacrylate, isobornyl methacrylate; cyclohexyl acrylate, 2-methylcyclohexyl acrylate, dicyclo Pentanyl acrylate, dicyclopentaoxyethyl acrylate, isobornyl acrylate, etc. Acrylic acid cyclic alkyl ester; aryl methacrylate such as phenyl methacrylate and benzyl methacrylate; aryl aryl ester such as phenyl acrylate and benzyl acrylate; dicarboxylic acid diester such as diethyl maleate, diethyl fumarate and diethyl itaconate; 2-hydroxy Hydroxyalkyl esters such as ethyl methacrylate and 2-hydroxypropyl methacrylate; styrene, α-methylstyrene, m-methylstyrene, p-methylstyrene, vinyltoluene, p-methoxystyrene, acrylonitrile, methacrylonitrile, vinyl chloride, vinylidene chloride Acrylamide, methacrylamide, vinyl acetate and the like. Among these, methacrylic acid alkyl esters, acrylic acid alkyl esters, styrene, dicyclopentanyl methacrylate, and p-methoxystyrene are preferably used. These may be used independently and may use 2 or more types together.

In the copolymer (A), the lower limit of the content of the structural unit (a2) is 10 mol%, and the upper limit is 95 mol%. If it is less than 10 mol%, the spacer particle dispersion containing the adhesive composed of the above mixture gels, and if it exceeds 95 mol%, the heat resistance and chemical resistance of the adhesive composed of the above mixture decrease. End up. A preferred lower limit is 30 mol%, and a preferred upper limit is 90 mol%.

Here, when producing a copolymer only from the monomer which becomes said structural unit (a1), and the monomer which becomes said structural unit (a2), an epoxy group and a carboxylic acid group react, and it bridge | crosslinks. The polymerization system may be gelled.
However, since the spacer particle dispersion containing the adhesive composed of the mixture contains the polyvalent compound (B) as the adhesive composed of the mixture, the cross-linking as seen in a normal acid-epoxy copolymer is used. Gelation due to the progress of the reaction does not occur, and the epoxy group content of the adhesive made of the mixture can be increased. Further, since the spacer particle dispersion liquid containing the adhesive composed of the above mixture can achieve a high concentration and low viscosity, it is possible to disperse the spacer particles by an ink jet apparatus, and on the substrate together with the spacer particles. The adhesive component consisting of the above-mentioned mixture dispersed on the surface has a high ability to fix the spacer particles on the substrate, and further, after curing, a high cross-linking density is obtained, thus forming a gap retaining material excellent in various resistances. Can do. Moreover, heat resistance can also be improved.

The method for producing the copolymer (A) having such a structural unit (a1) and the structural unit (a2) is not particularly limited. For example, the monomer to be the structural unit (a1) and the structural unit described above are used. A known method may be mentioned in which the monomer to be (a2) is copolymerized in a known solvent so as to have the above-mentioned blending ratio.

The polyvalent compound (B) functions as a curing agent for the copolymer (A). Examples of the polyvalent compound (B) include polyvalent carboxylic acid anhydrides and polyvalent carboxylic acids. , At least one selected from the group consisting of aromatic polyphenols and aromatic polyamines.

Examples of the polyvalent carboxylic acid anhydride include itaconic anhydride, succinic anhydride, citraconic anhydride, dodecenyl succinic anhydride, tricarbanilic anhydride, maleic anhydride, hexahydrophthalic anhydride, methyltetrahydrophthalic anhydride, and hymic anhydride. Aliphatic dicarboxylic anhydrides such as acids; alicyclic polycarboxylic dianhydrides such as 1,2,3,4-butanetetracarboxylic dianhydride and cyclopentanetetracarboxylic dianhydride; phthalic anhydride And aromatic polyvalent carboxylic acid anhydrides such as pyromellitic anhydride, trimellitic anhydride, and benzophenone tetracarboxylic anhydride; and ester group-containing acid anhydrides such as ethylene glycol bistrimellitic anhydride and glycerin tris anhydrous trimellitate. Of these, aromatic polycarboxylic anhydrides are preferred from the viewpoint of heat resistance.

Moreover, the epoxy resin hardening | curing agent which consists of a colorless acid anhydride marketed can also be used conveniently. Examples of commercially available epoxy resin curing agents made of unemployed acid anhydrides include Adeka Hardener EH-700 (manufactured by Asahi Denka Kogyo Co., Ltd.), Ricacid HH, Ricacid MH-700 (manufactured by Shin Nippon Chemical Co., Ltd.), EpiCure 126, EpiCure YH-306, EpiCure DX-126 (manufactured by Yuka Shell Epoxy Co., Ltd.), Epicron B-4400 (manufactured by Dainippon Ink & Chemicals, Inc.) and the like can be mentioned.

Examples of the polyvalent carboxylic acid include aliphatic polyvalent carboxylic acids such as succinic acid, glutaric acid, adipic acid, butanetetracarboxylic acid, maleic acid, and itaconic acid; hexahydrophthalic acid and 1,2-cyclohexanecarboxylic acid. 1,2,4-cyclohexanetricarboxylic acid, cyclopentanetetracarboxylic acid and other alicyclic polycarboxylic acids; phthalic acid, isophthalic acid, terephthalic acid, trimellitic acid, pyromellitic acid, 1,2,5,8 -Aromatic polyvalent carboxylic acids such as naphthalenetetracarboxylic acid. Of these, aromatic polycarboxylic acids are preferred from the standpoints of reactivity and heat resistance.
These hardening | curing agents may be used independently and 2 or more types may be used together.

In the adhesive comprising the above mixture, the compounding ratio of the copolymer (A) and the polyvalent compound (B) is not particularly limited, but the polyvalent compound is based on 100 parts by weight of the copolymer (A). A preferred lower limit of (B) is 1 part by weight, and a preferred upper limit is 100 parts by weight. If it is less than 1 part by weight, the heat resistance and chemical resistance of the cured product may be lowered. If it exceeds 100 parts by weight, a large amount of unreacted curing agent remains, and the heat resistance of the cured product and the liquid crystal Non-contaminating property may be reduced. A more preferred lower limit is 3 parts by weight, and a more preferred upper limit is 50 parts by weight.

In the spacer particle dispersion containing the adhesive composed of the mixture, the adhesive composed of the mixture may contain components other than the copolymer (A) and the polyvalent compound (B). Compounding agents such as curing accelerators and adhesion assistants may be blended as necessary.

The curing accelerator is generally used for accelerating the reaction between the epoxy group of the copolymer (A) and the polyvalent compound (B) and increasing the crosslinking density. For example, a secondary nitrogen atom Alternatively, a compound having a heterocyclic structure containing a tertiary nitrogen atom is suitable, and examples thereof include pyrrole, imidazole, pyrazole, pyridine, pyrazine, pyrimidine, indole, indal, benzimidazole, isocyanuric acid and the like. Specifically, 2-methylimidazole, 2-ethyl-4-methylimidazole, 2-heptadecylimidazole, 4-methyl-2-phenylimidazole, 1-benzyl-2-methylimidazole, 2-ethyl-4-methyl Examples include imidazole derivatives such as -1- (2′-cyanoethyl) imidazole, 2-ethyl-4-methyl-1- [2 ′-(3 ″, 5 ″ -diaminotriazinyl) ethyl] imidazole, and benzimidazole. Of these, 2-ethyl-4-methylimidazole, 4-methyl-2-phenylimidazole, and 1-benzyl-2-methylimidazole are preferably used.
These hardening accelerators may be used independently and 2 or more types may be used together.

When the curing accelerator is contained, the blending amount is not particularly limited, but a preferable lower limit is 0.01 part by weight and a preferable upper limit is 2 parts by weight with respect to 100 parts by weight of the copolymer (A). It is. If it is less than 0.01 part by weight, the effect of blending the curing accelerator can hardly be obtained, and if it exceeds 2 parts by weight, unreacted curing accelerator remains, and the heat resistance of the cured product and the liquid crystal Non-contamination may be reduced.

Further, in the spacer particle dispersion, the adhesive comprises a structural unit represented by the following general formula (1) and a structural unit represented by the following general formula (2), an unsaturated carboxylic acid and / or an unsaturated compound. A copolymer having a structural unit derived from a carboxylic acid anhydride, wherein the copolymer has a content of a structural unit represented by the following general formula (1) of 1 to 70 mol%, and the following general formula (2 The content of the structural unit represented by 10) to 98 mol% and the content of the structural unit derived from the unsaturated carboxylic acid and / or unsaturated carboxylic anhydride is 1 to 70 mol%. preferable. In addition, hereinafter, a structural unit represented by the following general formula (1) and a structural unit represented by the following general formula (2), and a structural unit derived from an unsaturated carboxylic acid and / or an unsaturated carboxylic anhydride. The adhesive which is a copolymer having is also referred to as “adhesive made of a copolymer”.

In the formula, R ¹ and R ³ each represent a hydrogen atom or a methyl group, R ² represents an alkyl group having 1 to 8 carbon atoms, and R ⁴ represents an alkyl group having 1 to 12 carbon atoms or 5 carbon atoms. Represents a cycloalkyl group of 12 or an aromatic group. Moreover, the said cycloalkyl group and aromatic group may have a substituent.

When the adhesive is an adhesive made of the copolymer, the spacer dispersion has a constituent unit derived from an unsaturated carboxylic acid and / or an unsaturated carboxylic acid anhydride. For this reason, the epoxy group and the carboxylic acid group contained in the adhesive made of the copolymer react with each other to make the polymerization system difficult to gel, and the storage stability is excellent. Furthermore, since the adhesive made of the copolymer is easily cured only by heating, it is not necessary to use a specific curing agent, and the gap maintaining material for the liquid crystal display device with extremely little contaminants on the alignment film and the liquid crystal on the substrate. Can be obtained. That is, by containing an adhesive made of the above copolymer as an adhesive, the spacer particles can be accurately and firmly arranged at predetermined positions on the substrate using an ink jet device, and the liquid crystal display device When used in the production, the contamination with respect to the alignment film and the liquid crystal is low.

The adhesive comprising the copolymer is composed of a structural unit represented by the general formula (1) (hereinafter also referred to as the structural unit (a)) and a structural unit represented by the general formula (2) (hereinafter referred to as the structural). A unit (b)) and a structural unit derived from an unsaturated carboxylic acid and / or an unsaturated carboxylic acid anhydride (hereinafter also referred to as a structural unit (c)).

The monomer to be the structural unit (a) is not particularly limited, and examples thereof include a radical polymerizable compound having the same epoxy group as the structural unit (a1) in the adhesive composed of the above-described mixture.

In the copolymer, the lower limit of the content of the structural unit (a) is 1 mol%, and the upper limit is 70 mol%. If it is less than 1 mol%, the heat resistance and chemical resistance of the adhesive comprising the copolymer will be reduced, and if it exceeds 70 mol%, a spacer dispersion containing the adhesive comprising the copolymer Will gel. A preferred lower limit is 5 mol%, and a preferred upper limit is 40 mol%. A more preferred upper limit is 20 mol%.

The monomer to be the structural unit (b) is not particularly limited, and examples thereof include the same monoolefin unsaturated compounds as the structural unit (a2) of the adhesive composed of the above-described mixture.

In the copolymer, the lower limit of the content of the structural unit (b) is 10 mol%, and the upper limit is 98 mol%. When the amount is less than 10 mol%, the spacer particle dispersion containing the adhesive made of the copolymer is gelled. When the amount exceeds 98 mol%, the heat resistance and chemical resistance of the adhesive made of the copolymer are increased. The nature will decline. A preferable lower limit is 20 mol%, and a preferable upper limit is 90 mol%.

Examples of the monomer serving as the structural unit (c) include monocarboxylic acids such as acrylic acid, methacrylic acid, and crotonic acid, and dicarboxylic acids such as maleic acid, fumaric acid, citraconic acid, mesaconic acid, and itaconic acid, and These anhydrides etc. are mentioned. Of these, acrylic acid, methacrylic acid, and maleic anhydride are preferably used. These may be used independently and may use 2 or more types together.

In the copolymer, the lower limit of the content of the structural unit (c) is 1 mol%, and the upper limit is 70 mol%. When the amount is less than 1 mol%, the heat resistance and chemical resistance of the adhesive made of the copolymer are lowered. When the amount is more than 70 mol%, the spacer particle dispersion containing the adhesive made of the copolymer is dispersed. The liquid will gel. A preferred lower limit is 5 mol% and a preferred upper limit is 40 mol%. A more preferred upper limit is 20 mol%.

Here, when producing a copolymer only from the monomer which becomes the said structural unit (a), and the monomer which becomes the said structural unit (b), an epoxy group and a carboxylic acid group react, and it bridge | crosslinks. The polymerization system may be gelled.
However, in the adhesive made of the copolymer, the monomer that becomes the structural unit (c) is copolymerized with the monomer that becomes the structural unit (a) and the monomer that becomes the structural unit (b) in the above-described range. Therefore, the epoxy group and the carboxylic acid group react with each other, so that the polymerization system is hardly gelled, and the storage stability is excellent.
In addition, the spacer particle dispersion containing the adhesive made of the copolymer can be easily cured only by heating, so that it is not necessary to use a specific curing agent, and the spacer particle dispersion It is possible to obtain a gap maintaining material for a liquid crystal display device in which the alignment film on the substrate from the liquid and the contaminants for the liquid crystal are extremely small.

The amount of the adhesive added to the spacer particle dispersion is not particularly limited, but the preferable lower limit is 0.001% by weight, and the preferable upper limit is 10% by weight. If the amount is less than 0.001% by weight, the effect of adding the adhesive, that is, the effect of fixing the spacer particles may not be obtained. If the amount exceeds 10% by weight, the spacer particles are covered with the adhesive after drying. As a result, the gap accuracy may deteriorate, or the viscosity of the spacer particle dispersion may increase and the discharge accuracy may deteriorate. A more preferred lower limit is 0.01% by weight, and a more preferred upper limit is 5% by weight.

In the present invention, as the solvent for the spacer particle dispersion liquid, a solvent having high hydrophilicity is preferably used as it is preferable for narrowing the gathering range of the spacer particles by gathering the spacers together. Therefore, an adhesive having a high hydrophilic solvent solubility is suitable so that the “adhesive made of a mixture” and the “adhesive made of a copolymer” can be easily dissolved or dispersed in the solvent of the spacer dispersion liquid. is there.
In addition, as the above-mentioned adhesive having high solubility in a hydrophilic solvent, as in the above-mentioned “adhesive composed of a mixture” and “adhesive composed of a copolymer”, polyvinyl alcohol or a modified product thereof, cellulose such as carboxymethylcellulose, etc. Such polysaccharide polymers and modified products thereof can also be used.
When such an adhesive is used in a spacer particle dispersion containing a solvent having a boiling point of 200 ° C. or higher and a surface tension of 42 mN / m or higher, the droplet diameter decreases and dissolves as the droplets dry. The existing adhesive shrinks along with it, so that the existing range of the adhesive after drying can be reduced.

From the viewpoint of solubility of the spacer particle dispersion in a solvent, the weight average molecular weight of the adhesive and the copolymer constituting the adhesive is preferably 400,000 or less, and more preferably 200,000 or less. If it exceeds 400,000, not only the solubility of the spacer dispersion liquid in the solvent is deteriorated, but also the viscosity of the spacer particle dispersion liquid is increased and thixotropy is generated, which has a problem of adversely affecting the discharge performance in the inkjet discharge. May occur. In addition, if it exceeds 400,000, the adhesive itself has a function as a surfactant such as a polymer dispersant, and the droplets of the spacer particle dispersion after landing on the substrate may not easily shrink. Conceivable.

In order to obtain an adhesive having high hydrophilic solvent solubility, in the adhesive made of a mixture and the adhesive made of a copolymer, the copolymer contains at least 20% by weight or more of monomer units having a hydrophilic functional group. It is preferable to contain, and it is more preferable to contain 40% by weight or more.
Examples of the monomer having a hydrophilic functional group include, in addition to the monomer that becomes the above-described structural unit (c: a structural unit derived from an unsaturated carboxylic acid and / or an unsaturated carboxylic acid anhydride), for example, a hydroxyl group, a sulfonyl group, and phosphonyl. And vinyl monomers having a hydrophilic functional group such as a group, amino group, amide group, ether group, thiol group, and thioether group. Among these, vinyl monomers having a hydroxyl group, a carboxyl group (carboxylic acid group), and an ether group are preferable because of little interaction with the liquid crystal.

The vinyl monomer having a hydrophilic functional group is not particularly limited. For example, 2-hydroxyethyl (meth) acrylate, 1,4-hydroxybutyl (meth) acrylate, (poly) caprolactone-modified hydroxyethyl (meth) ) Vinyl monomers having a hydroxyl group such as acrylate, allyl alcohol, glycerol monoallyl ether; Vinyl monomers having a sulfonyl group such as t-butylacrylamidesulfonic acid, styrenesulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid Monomer; Vinyl monomer having a phosphonyl group such as vinyl phosphate and 2- (meth) acryloyloxyethyl phosphate; Vinyl monomer having an amino group such as dimethylaminoethyl methacrylate and diethylaminoethyl methacrylate; ) Vinyl-based monomer having an ether group such as terminal alkyl ether of ethylene glycol (meth) acrylate, terminal alkyl ether of (poly) propylene glycol (meth) acrylate, tetrahydrofurfuryl (meth) acrylate; Vinyl monomers having a hydroxyl group and an ether group such as (meth) acrylate and (poly) propylene glycol (meth) acrylate; vinyl monomers having an amide group such as (meth) acrylamide, methylol (meth) acrylamide and vinylpyrrolidone Examples include a polymer. These vinyl monomers having a hydrophilic functional group may be used alone or in combination of two or more.

(Inkjet device)
Next, an ink jet apparatus used when the spacer particle dispersion is discharged onto a substrate in the present invention will be described.

The inkjet apparatus used in the present invention is not particularly limited, and an inkjet apparatus using a general ejection method is used. Examples of the ejection method include a piezo system that ejects liquid by vibration of a piezo element, and a thermal system that ejects liquid by utilizing expansion of the liquid due to rapid heating. Among them, the piezo method is preferable because the thermal influence on the spacer particle dispersion is small.

In the method for producing a liquid crystal display device of the present invention, the preferable lower limit of the amount of the spacer particle dispersion discharged from one nozzle at a time is 5 ng, and the preferable upper limit is 35 ng. If it is less than 5 ng, it may be difficult to discharge the spacer particle dispersion liquid. If it exceeds 35 ng, the amount of spacer particle dispersion liquid discharged on the substrate is too large, and it takes time to dry. In some cases, the spacer particles cannot be gathered effectively in a short time.

As a method for controlling the amount of the spacer particle dispersion discharged from one nozzle at a time, there are a method for optimizing the nozzle diameter and a method for optimizing the electric signal for controlling the ink jet head. The latter is particularly effective when a piezo ink jet apparatus is used.

It is preferable that the liquid contact part of the ink chamber containing the spacer particle dispersion of the ink jet apparatus is made of a hydrophilic material having a surface tension of 31 mN / m or more. As the material for the wetted part, hydrophilic organic materials such as hydrophilic polyimide can be used, but in view of durability, inorganic materials, that is, ceramics, glass, and metal materials such as stainless steel with low corrosiveness are preferable. Used.

In a normal head, a resin or the like is used for the liquid contact portion in order to ensure insulation or the like for the voltage application component. The resin used for the wetted part is often made of a material having a surface tension lower than 31 mN / m. In this case, when the spacer particle dispersion is introduced into the head, the familiarity of the spacer particle dispersion is poor and bubbles tend to remain. The nozzle in which bubbles remain may not be able to discharge the spacer particle dispersion.

The nozzle diameter of the ink jet apparatus is preferably 7 times or more the particle diameter of the spacer particles. When the nozzle diameter is less than 7 times, the nozzle diameter is too small with respect to the particle diameter of the spacer particles, and the discharge accuracy is lowered.

The reason why the discharge accuracy is lowered is considered as follows. For example, in a piezo-type ink jet apparatus, ink is sucked into an ink chamber adjacent to the piezo element by vibration of the piezo element, and then the ink is sent out from the ink chamber and ejected from the tip of the nozzle. The droplet discharge method includes a meniscus at the tip of the nozzle immediately before discharge, that is, a pulling method in which the interface between the ink and gas is drawn, and a push-out method in which the liquid is directly pushed out from the position where the meniscus is on standby. There is a batting method. In a general ink jet apparatus, since the ejected droplets are small, the former striking method is mainstream. In the present invention, since the nozzle diameter is required to be large to some extent and the ejected droplets are small, the striking method is effective.

However, in the pulling method, the meniscus is drawn immediately before discharge. For this reason, when the nozzle diameter is small, for example, when the nozzle diameter is less than seven times the particle diameter of the spacer particles, as shown in FIG. The drawn meniscus 21 may not be axially symmetric. Therefore, when the meniscus 21 is pushed out after the meniscus 21 is drawn, it is considered that the droplets of the spacer particle dispersion liquid 23 bend without going straight. In this case, the discharge accuracy decreases. If the nozzle diameter is too large in order to eliminate the bending of the droplets during ejection, the ejected droplets become larger and the landing diameter of the droplets also becomes larger. Therefore, the arrangement accuracy of charged ink and spacer particles 22 is lowered.

When the nozzle diameter is large, for example, when the nozzle diameter is 7 times or more the particle diameter of the spacer particles, as shown in FIG. 4B, even if the spacer particles 22 exist in the vicinity of the drawn meniscus 21, The meniscus 21 is not affected by the spacer particles 22. Therefore, the meniscus 21 is drawn in axial symmetry. Therefore, it is considered that when the meniscus 21 is pushed out after the meniscus 21 is drawn, the droplets of the spacer particle dispersion liquid 23 advance straight. In this case, the discharge accuracy is good.

Although it does not specifically limit as a nozzle diameter of the said inkjet apparatus, A preferable minimum is 20 micrometers and a preferable upper limit is 100 micrometers. If it is less than 20 μm, when spacer particles having a particle diameter of 2 to 10 μm are discharged, the difference from the particle diameter is too small and the discharge accuracy may be reduced, or the nozzle may be blocked and the discharge may be disabled. is there. If it exceeds 100 μm, the diameter of the ejected droplets increases, and the diameter of the droplets ejected on the substrate also increases, so that the arrangement accuracy of the spacer particles may be rough.

The diameter of the droplets ejected from the nozzle is not particularly limited, but a preferred lower limit is 10 μm and a preferred upper limit is 80 μm.
The method for controlling the diameter of the droplets ejected from the nozzle within the above preferable range is not particularly limited, and examples thereof include a method for optimizing the nozzle diameter and a method for optimizing the electric signal for controlling the ink jet apparatus. Any method may be adopted. In particular, when using a piezo ink jet apparatus, the latter method is preferably employed.

Further, the diameter of the droplets ejected on the substrate is not particularly limited, but a preferable lower limit is 30 μm and a preferable upper limit is 150 μm. In order to make it less than 30 μm, it is necessary to make the nozzle diameter very small, and there is a possibility that the possibility of nozzle clogging by spacer particles increases, or the accuracy of nozzle processing must be improved. When it exceeds 150 μm, the arrangement accuracy of the spacer particles may become rough.

The head of the ink jet apparatus is provided with a plurality of nozzles as described above according to a certain arrangement method. For example, 64 or 128 nozzles are provided at equal intervals in a direction orthogonal to the moving direction of the head. The nozzles may be provided in a plurality of rows.

The interval between the nozzles in the ink jet apparatus is restricted by the structure of the piezo element and the nozzle diameter. Therefore, in the case where the spacer particle dispersion is discharged to the substrate at intervals different from the nozzle intervals, as described above, various heads are prepared for the discharge intervals. Must. However, it is difficult to prepare various heads. Therefore, if the discharge interval is smaller than the head interval, the head, which is normally arranged at right angles to the head scanning direction, is kept parallel to the substrate, and the head is tilted or rotated in a plane parallel to the substrate. To discharge. On the other hand, when the discharge interval is larger than the nozzle interval, the spacer particle dispersion liquid is not discharged using all the nozzles, and only a part of the nozzles are discharged, or the head is further inclined.

In order to increase production efficiency and the like, a plurality of heads can be attached to the ink jet apparatus. However, when the number of attached heads is increased, the control becomes even more difficult.

FIGS. 10A and 10B schematically show an example of a head of an ink jet apparatus used in the present invention. FIG. 10A is a partially cutaway perspective view schematically showing the structure of an example of an inkjet head. FIG. 10B is a partially cutaway perspective view showing a cross-sectional structure in the nozzle hole portion.

As shown in FIGS. 10A and 10B, the head 100 includes an ink chamber 101 in which ink is filled in advance by suction or the like, and an ink chamber 102 into which ink is sent from the ink chamber 101. A nozzle hole 104 extending from the ink chamber 102 to the ejection surface 103 is formed in the head 100. The ejection surface 103 is previously subjected to water repellent treatment in order to prevent contamination with ink. The head 100 is provided with temperature control means 105 for adjusting the viscosity of the ink. The head 100 has a function of sending ink from the ink chamber 101 to the ink chamber 102. The head 100 includes a piezo element 106 that functions to eject ink fed into the ink chamber 102 from the nozzle hole 104.

In the head 100, temperature control means 105 is provided. Therefore, when the viscosity of the ink is too high, the ink can be heated by the heater to reduce the viscosity of the ink. On the other hand, when the ink viscosity is too low, the ink can be cooled by Peltier to increase the ink viscosity.

(Substrate for liquid crystal display)
Examples of the first and second substrates for the liquid crystal display device used in the present invention include glass and resin plates that are usually used as panel substrates for liquid crystal display devices. Further, as the first substrate or the second substrate, a substrate in which a color filter is provided in the pixel region can be used. In this case, the pixel area is defined by a black matrix, and the black matrix constitutes a non-pixel area. The black matrix is made of a metal such as chrome that hardly transmits light or a resin in which carbon black or the like is dispersed.

In the method for manufacturing a liquid crystal display device of the present invention, a spacer particle dispersion liquid in which spacer particles are dispersed is ejected from a nozzle of an ink jet device onto the first substrate, and is applied to a non-pixel region on the first substrate. In the step of arranging the spacer particles in the corresponding region, the region corresponding to the non-pixel region on the first substrate as described with reference to FIG. 2 by using the ink jet apparatus and the spacer particle dispersion described above. Spacer particles can be disposed on the substrate.

As described above, when the spacer particle dispersion is discharged and landed on the substrate, the receding contact angle of the spacer particle dispersion is preferably 5 degrees or more. As a method of increasing the receding contact angle, for example, a method of setting the surface of the substrate to a low energy surface can be mentioned.

As a method of making the surface of the substrate a low energy surface, a method of providing a resin having a low energy surface such as a fluorine film or a silicone film on the surface of the substrate, an alignment film for regulating the alignment of liquid crystal molecules, usually 0 The method of providing the resin thin film which is 0.1 micrometer or less on a substrate surface is mentioned. Generally, a method of providing a resin thin film on the substrate surface is performed. As a material constituting the resin thin film, a polyimide resin is usually used. The polyimide resin film is formed by applying a polyamic acid soluble in a solvent to a substrate and then thermally polymerizing it, or applying a soluble polyimide resin to a substrate and drying it. As the polyimide resin, a resin having a long side chain and a main chain is more preferably used so that the surface of the substrate can be a low energy surface. The coated alignment film is preferably rubbed on the surface for the purpose of controlling the alignment of the liquid crystal. As a solvent for the spacer particle dispersion liquid, it is preferable to select a solvent that does not contaminate the alignment film by penetrating or dissolving in the alignment film.

The first substrate from which the spacer particle dispersion is discharged preferably has a portion having a low energy surface in a region corresponding to the non-pixel region. That is, it is preferable that the droplets of the spacer particle dispersion are disposed at a location having a low energy surface. Here, the region corresponding to the non-pixel region refers to the non-pixel region of the substrate having the non-pixel region, that is, the above-described black matrix forming portion in the case of a color filter substrate, for example. Alternatively, when a substrate having a non-pixel area is overlapped with the other substrate, an area facing the non-pixel area of the substrate having the non-pixel area is an area corresponding to the non-pixel area. is there. For example, in the case of a TFT liquid crystal panel, the other substrate is a TFT array substrate. When the TFT array substrate and a substrate having a non-pixel region are overlapped, the wiring portion of the TFT array substrate corresponds to the non-pixel region. It is an area to do.

The upper limit with the preferable surface energy of the location which has the low energy surface of the said substrate surface is 50 mN / m. If it exceeds 50 mN / m, as long as a spacer particle dispersion having a surface tension that can be discharged using an ink jet device is used, the discharged droplets wet and spread on the substrate, and the spacer particles may protrude from the non-pixel region. is there. A more preferred upper limit is 40 mN / m.

The low-energy surface configured by providing an alignment film or the like on the substrate surface may be only a portion where the spacer particle dispersion is landed or the entire substrate surface. Considering the complexity of processes such as patterning, the entire substrate surface is usually a low energy surface.

In the substrate, it is preferable that a step is provided in the landing center portion of the droplet of the spacer particle dispersion. In this case, since the spacer particles are effectively moved to a predetermined position, the arrangement accuracy of the spacer particles can be increased. Further, it is preferable that electrostatically charged charged ink is ejected to the landing center portion of the spacer particle dispersion liquid droplets, and the charged ink is dried.

The step provided on the surface of the substrate refers to an unintentional unevenness in which a difference in height from the surroundings is formed by wiring provided on the substrate, or an unevenness intentionally provided to collect spacer particles. The uneven structure is not limited. Therefore, the level difference refers to a level difference between the concave or convex part in the concavo-convex shape and the flat part of the substrate, that is, the reference surface.

Specifically, as the step, for example, in a TFT array substrate, a step of about 0.2 μm due to a gate electrode or a source electrode as shown in FIGS. 5A to 5C, as shown in FIG. And a step of about 1.0 μm due to the array.

Further, for example, in the color filter substrate, as shown in FIGS. 5D to 5F and FIG. 5H, a concave step of about 1.0 μm between the color filters on the black matrix can be mentioned.

When the particle diameter of the spacer particles is D (μm) and the step height difference is B (μm), the step height difference preferably satisfies the relationship of 0.01 μm <| B | <0.95D. If the level difference of the step is smaller than 0.01 μm, the spacer particles may hardly gather around the step, and if it exceeds 0.95D, the substrate gap adjustment effect by the spacer particles may not be sufficient.

When there is a step on the surface of the substrate, since a part of the droplet is fixed to the step portion at the stage where the spacer particle dispersion is discharged onto the substrate and dried, the spacer particles are located at a limited position around the step. Can be arranged. Therefore, by providing a step in the region corresponding to the non-pixel region, the spacer particles can be collected in the region corresponding to the non-pixel region.

As shown in FIGS. 6A to 6C, after the spacer particle dispersion is dried, the positions where the spacer particles 31 are arranged are generally corners in the case of the protrusions 33, and may be the recesses 33. It will be in that dent. When the size of the recess 33 is larger than the particle diameter of the spacer particles or the landing diameter of the droplets of the discharged spacer particle dispersion liquid, the spacer particles are not only in the recess 33 but also in the periphery of the recess 33. Is placed.

If there is a metal species in the vicinity of a stepped part formed by wiring or the like, or an alignment film, etc., or if the wiring part contains a charge control agent, electrostatic interaction, that is, The spacer particles in the droplet move to a specific position by the electrostatic electrophoresis effect. Therefore, in order to control the gathering of the spacer particles, it is preferable to adjust the metal type and the type of the charge control agent. Even when the surface treatment is applied to the wiring, the spacer particles in the droplet move to a specific position due to the electrostatic electrophoresis effect. In this case, it is preferable to change the functional group of the compound using, for example, an ionic functional group with respect to the compound used for the surface treatment such as wiring. It is possible to control the gathering of the spacer particles by applying a positive or negative voltage to the wiring such as the source wiring and the gate wiring and the entire substrate surface so as not to damage the circuit. The number of spacer particles arranged on the substrate (dispersion density) is preferably in the range of 50 to 350 particles / mm ² .

The spacer particle dispersion liquid is preferably discharged onto the substrate at intervals equal to or greater than the value represented by the following formula (1). The discharge interval refers to the shortest distance between two droplets of the spacer particle dispersion that has landed on the substrate.

3 5 × [D / (2-3 cos θ + cos ³ θ)] ^1/3 (μm) (1)
In the above formula (1), D represents the particle diameter (μm) of the spacer particles, and θ represents the above-mentioned initial contact angle.

When ejected at an interval smaller than the value represented by the above-described formula (1), the spacer particle dispersion droplets that have landed on the substrate coalesce, and the spacer particles do not gather toward one place during the drying process. Sometimes. In this case, the arrangement accuracy of the spacer particles after drying is lowered. In addition, if the nozzle diameter is reduced to reduce the amount of spacer particle dispersion discharged from one nozzle, the particle diameter of the spacer particles becomes relatively larger than the nozzle diameter. The spacer particles cannot always be ejected linearly in the direction, causing flight bending, and the arrangement accuracy of the spacer particles decreases. In addition, the nozzle may be blocked by the spacer particles.

As long as the spacer particles are arranged in a region corresponding to a non-pixel region such as black matrix or a region corresponding to a non-pixel region such as a wiring, the portion and arrangement pattern are not particularly limited. However, in order to prevent the spacer particles from protruding into the pixel region, for example, when the region corresponding to the non-pixel region of the substrate is formed in a lattice shape, the region corresponding to the lattice-shaped non-pixel region More preferably, the spacer particle dispersion is discharged aiming at lattice points that intersect vertically and horizontally.

The arrangement number of the spacer particles in one place can be appropriately set depending on the arrangement place, but generally it is preferably about 1 to 12 pieces. The average number of arrangement is preferably about 2 to 6. The arrangement number can be appropriately adjusted according to the particle diameter of the spacer particles and the concentration of the spacer particle dispersion.

When the spacer particle dispersion is discharged onto the substrate, the head of the ink jet apparatus may be scanned once or may be divided into a plurality of times. In particular, when the interval at which the spacer particles are arranged is smaller than the value represented by the above formula (1), the spacer particle dispersion is discharged at an interval that is an integer multiple of the value represented by the above formula (1). Then, after drying the spacer particle dispersion, it is preferable to move the head by the interval and discharge the spacer particle dispersion again. When discharging the spacer particle dispersion liquid, for example, the head moving direction may be alternately changed every time, and the head particle may be discharged while reciprocating. Alternatively, the head particle may be discharged while moving only in a certain direction.

As a method of arranging the spacer particles on the substrate, as described in JP-A-2002-015493, when a perpendicular is drawn on the surface of the substrate, the head is tilted so as to have a predetermined angle with respect to the perpendicular. The liquid droplets are discharged, and the relative moving speed between the head and the substrate is controlled. By doing so, the landing diameter of the droplets of the spacer particle dispersion liquid can be reduced, and the spacer particles can be arranged with high accuracy in a region corresponding to the non-pixel region.

Moreover, when the convex part is formed in the non-pixel area | region of the substrate surface which discharges the said spacer particle dispersion liquid with an inkjet apparatus, it is preferable to discharge the said spacer particle dispersion liquid on this convex part. Spacer particles can be arranged on the convex portions. For example, even when minute spacer particles having a particle size of about 5 μm or less are used, the thickness of the liquid crystal layer of the liquid crystal display device to be manufactured is in an appropriate range. It can be. In this case, the spacer particle dispersion has a spacer particle diameter of 5 μm or less, a surface tension at 20 ° C. of 33 mN / m or more, and a spacer particle concentration of 0.01 to 5% by weight. In this step of arranging the spacer particles, it is preferable that the weight of the spacer particle dispersion discharged from one nozzle at a time is 5 to 20 ng. Since the weight of the spacer dispersion liquid ejected from one nozzle at a time is 5 to 20 ng, the landing diameter of the droplets of the spacer particle dispersion liquid ejected on the convex portions can be reduced. The spacer particles can be arranged with high accuracy on the convex portions formed in the region corresponding to the non-pixel region on the surface.

The convex portion may have a lattice shape or a shape having a length direction and a width direction. The shape having the length direction and the width direction includes a rectangle, an ellipse, and the like.

When the spacer particle dispersion is discharged onto the protrusion, the protrusion has a lattice shape, and the width of the protrusion at the portion where the spacer particle dispersion is discharged has a lower limit of 15 μm and an upper limit of 15 μm. It is preferable that it is 40 micrometers. When the width of the convex portion is in the above range, the spacer particle dispersion discharged onto the convex portion can be reliably prevented from protruding from the convex portion, and the spacer particles can be arranged with higher accuracy. it can. Therefore, the display image quality of the liquid crystal display device to be manufactured can be improved.

(Method for drying spacer particle dispersion)
A method of discharging the spacer particle dispersion liquid onto the substrate and drying the spacer particle dispersion liquid after the discharged spacer particle dispersion liquid has landed on the substrate surface will be described.

The method for drying the spacer particle dispersion after the spacer particle dispersion has landed on the substrate surface is not particularly limited, and includes a method for heating the stage on which the substrate is placed, a method for blowing hot air on the substrate, a far infrared ray, and the like. The method of heating a board | substrate by this, the method of drying the spacer particle dispersion liquid discharged on the board | substrate by reduced pressure drying, etc. are mentioned. In the drying process, in order to gather the spacer particles near the landing center of the droplet, the drying temperature, the drying time, the boiling point of the dispersion, the surface tension of the dispersion, the contact angle of the dispersion with the alignment film, the spacer in the dispersion It is preferable to set the particle concentration and the like to appropriate conditions.

The method of drying the substrate under reduced pressure as a method for drying the spacer particle dispersion discharged onto the substrate does not require heating the substrate, and the substrate, the alignment film on the substrate, and the spacer particles are damaged by heating. It is preferable because it is not present.

When the spacer particle dispersion liquid discharged on the substrate is dried by drying under reduced pressure, the spacer particle dispersion liquid may be dried by putting the substrate on which the spacer particle dispersion liquid is discharged into a pressure reducing apparatus, or a spacer particle arrangement apparatus. The spacer particle dispersion may be dried by placing itself in a vacuum dryer. By doing so, the drying speed of the spacer particle dispersion on the substrate can be adjusted. Examples of the decompression device include a decompression chamber in which a substrate is placed, and a decompression chamber having a larger capacity than that of the decompression chamber, for example, a decompression tank that has been decompressed in advance, is connected to the decompression device. This is preferable because the pressure can be reduced.

In order to gather the spacer particles in the vicinity of the droplet landing center point in the drying process, it is preferable that the spacer particles are dried for some time so that the liquid does not disappear while the spacer particles move on the substrate surface. That is, it is preferable to dry at a temperature at which the solvent does not dry rapidly. When a high-temperature solvent is in contact with the alignment film for a long time, the alignment film may be contaminated and the display image quality of the liquid crystal display device may be impaired. Therefore, drying at a low temperature is preferable.

If a spacer particle dispersion is used under conditions where the solvent tends to volatilize at room temperature or the solvent volatilizes abruptly, the spacer particle dispersion near the nozzles of the ink jet device can easily be dried, resulting in poor ejection properties. . Further, when the spacer particle dispersion is produced or the spacer particle dispersion is stored, the spacer particle dispersion may be dried and the spacer particles may be aggregated.

The surface temperature of the substrate when the spacer particle dispersion reaches the substrate surface is preferably 20 ° C. or more lower than the boiling point of the lowest boiling solvent contained in the spacer particle dispersion. When the surface temperature of the substrate is higher than the boiling point of the lowest boiling point solvent −20 ° C., the lowest boiling point solvent evaporates rapidly, making it difficult for the spacer particles to move. The droplets containing the spacer particles move around the substrate surface, and the arrangement accuracy of the spacer particles may be significantly reduced.

After the spacer particle dispersion has landed on the substrate surface, the solvent is dried while gradually raising the surface temperature of the substrate. At this time, the surface temperature of the substrate until the drying is completed is preferably 90 ° C. or less, and more preferably 70 ° C. or less. If the surface temperature of the substrate until the drying is completed exceeds 90 ° C., the alignment film may be contaminated and the display image quality of the liquid crystal display device may be deteriorated. Note that the time when the droplets on the substrate surface disappear is the time when drying is completed.

After drying of the spacer particle dispersion liquid is completed, the substrate may be further heated to a temperature of about 120 to 230 ° C., for example, in order to enhance the adhesion of the spacer particles to the substrate or remove the residual solvent.

The method for manufacturing a liquid crystal display device according to the present invention includes a step of overlapping the first substrate on which the spacer particles are arranged on the second substrate so as to face each other through the spacer particles, And a step of injecting liquid crystal between the second substrates or arranging the liquid crystal on the first substrate or the second substrate before the step of superimposing the first and second substrates.

That is, the first substrate on which the spacer particles are arranged by the above-described process is overlapped with the second substrate on which the spacer particles are not arranged so as to face each other through the spacer particles. The first and second substrates are, for example, heat-pressed using a peripheral sealing agent in the vicinity of the outer peripheral edge, and then a liquid crystal is filled in the gap between the first and second substrates to produce a liquid crystal display device. (Vacuum injection method).

Alternatively, for example, a peripheral sealing agent is applied in the vicinity of the outer peripheral edge of either the first substrate or the second substrate, and the liquid crystal is dropped in a range surrounded by the peripheral sealing agent. Thereafter, it is bonded to the other substrate, the sealing agent is cured, and a liquid crystal display device is manufactured (liquid crystal dropping method).

According to the manufacturing method of the liquid crystal display device of the present invention, the spacer particles can be arranged with high accuracy in the region corresponding to the non-pixel region on the substrate using the ink jet device. For example, as shown in FIG. The liquid crystal display device having the structure can be preferably manufactured.
The liquid crystal display device obtained by the method for producing a liquid crystal display device of the present invention is also one aspect of the present invention.

In the present invention, the spacer particle dispersion liquid contains at least a solvent having a boiling point of 200 ° C. or more and a surface tension of 42 mN / m or more, and is ejected from one nozzle at a time in the step of arranging the spacer particles. Since the lower limit of the amount of the solvent having a boiling point of 200 ° C. or higher and a surface tension of 42 mN / m or higher is 15 ng and the upper limit is 15 ng, the spacer particles are discharged onto the substrate. After that, when dried, the spacer particles can be effectively gathered to specific locations. Therefore, the spacer particles can be arranged with high accuracy in a region corresponding to the non-pixel region of the substrate. In addition, since the spacer particle dispersion can be dried at a low temperature in a short time, a liquid crystal display device can be produced efficiently. In the obtained liquid crystal display device, since the spacer particles are arranged with high accuracy in the region corresponding to the non-pixel region, there is no light leakage and the display image quality is excellent.

After the step of disposing spacer particles in a region corresponding to the non-pixel region on the first substrate, the second substrate is arranged so that the first substrate on which the spacer particles are disposed is opposed to the spacer substrate through the spacer particles. In the case of further comprising a step of drying the spacer particle dispersion discharged on the substrate by drying under reduced pressure before the step of superimposing on the substrate, there is no need to apply heat to the substrate, and the substrate and the alignment film on the substrate Since the spacer particles are not damaged by heating, a liquid crystal display device having excellent display image quality can be obtained.

In the step of arranging the spacer particles, when the lower limit of the amount of the spacer particle dispersion discharged from one nozzle at a time is 5 ng and the upper limit is 35 ng, when the spacer particle dispersion is dried, the non-pixel The spacer particles can be collected more effectively in a short time in the region corresponding to the region. Therefore, the display image quality of the obtained liquid crystal display device can be improved.

The liquid crystal display device obtained by the method for manufacturing a liquid crystal display device of the present invention is excellent in display image quality without light leakage because the spacer particles are arranged with high accuracy in the region corresponding to the non-pixel region.

The spacer particle dispersion of the present invention contains at least a solvent having a boiling point of 200 ° C. or higher and a surface tension of 42 mN / m or higher, a boiling point of 200 ° C. or higher and a surface tension of 42 mN / m or higher. Is contained in an amount of 1% by weight or more, the spacer particles can be effectively gathered to a specific position when the spacer particles are discharged onto the substrate and then dried. Therefore, the spacer particles can be arranged with high accuracy in a region corresponding to the non-pixel region of the substrate. The display image quality of the obtained liquid crystal display device can be improved.

When the solvent having a boiling point of 200 ° C. or higher and a surface tension of 42 mN / m or higher is at least one selected from the group consisting of 1,3-propanediol, 1,4-butanediol and glycerin The spacer particles can be arranged with higher accuracy in the region corresponding to the non-pixel region of the substrate. Therefore, the display image quality of the obtained liquid crystal display device can be improved.

1 is a partially cutaway front sectional view schematically showing a liquid crystal display device obtained by a method for manufacturing a liquid crystal display device according to an embodiment of the present invention. (A)-(c) is a partial notch front sectional drawing which shows the process in which a spacer particle | grain is arrange | positioned in steps. The partial notch front sectional drawing which shows the 1st board | substrate with which spacer particle | grains are arrange | positioned. It is a figure which shows typically a state when discharging a droplet from the nozzle of an inkjet apparatus, (a) shows the case where a meniscus is not an axis | shaft object, (b) shows the case where a meniscus is an axis | shaft 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 figure which shows typically the position where a spacer particle | grain remains. (A) is a partial notch top view which expands and shows the state by which the black matrix was provided in the inner surface of a glass substrate, when comprising the color filter substrate used by an Example and a comparative example. (B) is a partial notch front sectional drawing which expands and shows the color filter board | substrate used by an Example and a comparative example. (A) is a partial notch top view which expands and shows the state in which the level | step difference was provided in the inner surface of a glass substrate, when comprising 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 the 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) is a partial notch perspective view which shows typically the structure of an example of the head of an inkjet apparatus, (b) is the partial notch perspective view which shows typically the cross-sectional structure in a nozzle hole part. Front sectional drawing which shows typically an example of the conventional liquid crystal display device.

Hereinafter, embodiments of 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)
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 in a separable flask.
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 charged into a separable flask and sufficiently stirred. . Thereafter, 140 parts by weight of ion-exchanged water was further added. The solution was allowed to react 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 three types of spacer particles having an average particle size of 3, 4 or 5 μm and a CV value of 3.0%.

(Surface modification of spacer particles)
(Spacer particles SA)
In a mixture of 20 parts by weight of dimethyl sulfoxide (DMSO), 2 parts by weight of hydroxymethyl methacrylate, and 18 parts by weight of N-ethylacrylamide, the average particle size obtained was 3, 4 or 5 μm, and the CV value was 3.0. % Of spacer particles of 5% was added and dispersed uniformly using a sonicator. Thereafter, nitrogen gas was introduced into the reaction system, and stirring was continued at 30 ° C. for 2 hours. Next, 10 parts by weight of a 0.1 mol / L ceric ammonium nitrate solution prepared with a 1N nitric acid aqueous solution was added and reacted for 5 hours. After completion of the reaction, the spacer particles and the reaction solution were separated by filtration using a 2 μm membrane filter. The spacer particles were sufficiently washed with ethanol and acetone, and dried under reduced pressure in a vacuum drier to obtain three types of spacer particles SA having an average particle diameter of 3, 4 or 5 μm.

(Spacer particles SB)
5 parts by weight of spacer particles having an average particle diameter of 4 μm and a CV value of 3.0% obtained by the preparation of the spacer particles, 20 parts by weight of dimethyl sulfoxide (DMSO), 2 parts by weight of hydroxymethyl methacrylate, and methacrylic acid 16 The mixture was put into a mixture of parts by weight and 2 parts by weight of lauryl acrylate, and uniformly dispersed using an ultrasonic machine. Thereafter, similarly to the spacer particles SA, spacer particles SB having an average particle diameter of 4 μm were obtained.

(Spacer particles SC)
5 parts by weight of spacer particles having an average particle diameter of 4 μm and a CV value of 3.0% obtained by the preparation of spacer particles, 20 parts by weight of dimethyl sulfoxide (DMSO), 2 parts by weight of hydroxymethyl methacrylate, and polyethylene glycol methacrylate (Molecular weight 800) The mixture was mixed with 18 parts by weight and uniformly dispersed using an ultrasonic machine. Thereafter, similarly to the spacer particles SA, spacer particles SC having an average particle diameter of 4 μm were obtained.

(Preparation of spacer particle dispersion)
A necessary amount of the obtained spacer particles was taken so as to have a predetermined particle concentration, and it was slowly added into a solvent having a composition shown in Tables 1 to 4 below, and was sufficiently stirred and dispersed using an ultrasonic machine. Thereafter, the mixture was filtered using a stainless mesh having an opening of 10 μm to remove aggregates, thereby obtaining a spacer particle dispersion.

The surface tension at 20 ° C. of the obtained spacer particle dispersion was measured by the Wilhelmy method using a platinum plate. In addition, after introducing the spacer particle dispersion liquid to a height of 10 cm into a test tube having an inner diameter of 5 mm, when standing, the time until the spacer particle deposition is visually confirmed on the bottom of the test tube is measured. The sedimentation rate of the particle dispersion was evaluated. The measurement results are shown in Tables 1 to 4 below.

(Production of substrate)
A color filter substrate 51, which is a substrate for a liquid crystal test panel, and TFT array model substrates 61A, 61B provided with a step which is a counter substrate of the color filter substrate 51 were prepared.

(Color filter substrate)
FIG. 7A is an enlarged partial cutaway plan view of a glass substrate provided with a black matrix used for the color filter substrate 51. FIG. 7B is an enlarged partial cutaway front sectional view of a part of the color filter substrate 51.

The color filter substrate 51 having a smooth surface used in Examples and Comparative Examples was produced as follows.

As shown in FIGS. 7A and 7B, a black matrix 53 (width 25 μm, vertical interval 150 μm, horizontal interval 75 μm, thickness 0) made of metallic chromium on a 300 mm × 360 mm glass substrate 52 by a normal method. .2 μm). On and between the black matrix 53, 54 pixels (thickness 1.5 μm) of color filters composed of three colors of RGB were formed so as to have a flat surface. An overcoat layer 55 and an ITO transparent electrode 56 having a substantially constant thickness were provided thereon.

Further, a solution containing polyimide was uniformly applied on the ITO transparent electrode 56 by spin coating. After coating, the film was dried at 80 ° C., then baked at 190 ° C. for 1 hour, and cured to form an alignment film 57 having a substantially constant thickness.

The alignment film 57 is made of any of the following three types of alignment films PI1, PI2 and PI3. The following polyimide resin solution was used to form an alignment film of PI1, PI2 or PI3. 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: Product 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. 8A is an enlarged partial cutaway plan view of a glass substrate provided with a step used for a TFT array model substrate. FIG. 8B is an enlarged partial cutaway front view of a part of the TFT array model substrate.

The TFT array model substrate 61A provided with the steps used in the examples and comparative examples was manufactured as follows.

As shown in FIGS. 8A and 8B, a step 63 (made of copper is formed on a 300 mm × 360 mm glass substrate 62 at a position facing the black matrix 53 of the color filter substrate 51 by a conventionally known method. Width 8 μm, thickness 5 nm). An ITO transparent electrode 64 having a substantially constant thickness was provided thereon, and an alignment film 65 having a substantially constant thickness was formed by the method described above. In the TFT array model substrate 61A, in the portion where the step 63 is formed, the alignment film 65 is raised to form a convex portion, and the height of the convex portion, that is, the step on the substrate surface is 5 nm. .

In forming the alignment film 65, the same polyimide resin solution as that of the alignment film 57 of the color filter substrate 51 as the counter substrate was used.

Separately, a TFT array model substrate 61B provided with a step was produced. The TFT array model substrate 61B is different from the TFT array model substrate 61A described above only in the height of the step. That is, in the TFT array model substrate 61B, the height of the step 63 is set to 200 nm, and a step of 200 nm is provided on the substrate surface. In the TFT array model substrate 61B, an alignment film 65 made of PI3 is formed.

(Inkjet device)
A piezo-type ink jet apparatus equipped with a head having a nozzle diameter of 40 μm was prepared. The liquid contact part of the ink chamber of this head was made of a glass ceramic material. As the nozzle, a nozzle surface having a fluorine-based water-repellent finish was used.

(Spacer particle arrangement)
The spacer particle dispersions shown in Tables 1 to 4 were transferred to a step of arranging spacer particles on the color filter substrate 51 or one of the TFT array model substrates 61A and 61B. In addition, arrangement | positioning of the spacer particle | grains was started after throwing away 0.5 mL of the initial spacer particle dispersion liquid discharged from the nozzle of an inkjet apparatus.

The color filter substrate 51 or the TFT array model substrates 61A and 61B were placed on a stage heated to 45 ° C. with a heater. Thereafter, using the above-described ink jet device, the spacer particle dispersion is discharged on the black matrix 53 portion on the color filter substrate 51 or on the step portion corresponding to the black matrix 53 of the TFT array model substrates 61A and 61B. did.

After introducing the spacer particle dispersion into the ink chamber of the inkjet apparatus, the time until ejection was changed. That is, the case where the spacer particle dispersion was discharged immediately after the introduction (initial) and the case where the spacer particle dispersion was left to discharge after introduction for 1 hour (after 1 hour) were evaluated.

The distance between the nozzle tip surface and the substrate surface during ejection was 0.5 mm. The ink jet apparatus was a double pulse system. 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. After discharge, the initial contact angle (θ) of the spacer particle dispersion liquid droplet to the substrate was measured with a contact angle meter. The results are shown in Tables 1-4.

After discharging the spacer particle dispersion, the spacer particle dispersion that landed on the color filter substrate 51 or the TFT array model substrates 61A and 61B was dried.

In Examples 1 to 24 and Comparative Examples 1 to 5, the spacer particle dispersion discharged on the substrate was dried on the stage heated to 45 ° C. with a heater, and it was visually confirmed that the spacer particle dispersion was completely dried. Confirmed with. Thereafter, the remaining solvent was removed, the substrate was placed on a hot plate heated to 150 ° C., and heated for 15 minutes to fix the spacer particles to the substrate.

In Examples 25 and 26, the substrate on which the spacer particle dispersion was discharged was placed in a decompression device, and the spacer particle dispersion was dried. The temperature during vacuum drying was 45 ° C., and the degree of vacuum was 10 mmHg.

(Production of liquid crystal display device for evaluation)
The color filter substrate 51 in which spacer particles are arranged on either one of the substrates and the TFT array model substrate 61A or the TFT array model substrate 61B were bonded together using a peripheral sealant. After bonding, the sealing agent was heated at 150 ° C. for 1 hour and cured to produce an empty cell so that the cell gap was the particle diameter of the spacer particles. Thereafter, the liquid crystal was filled between the two bonded substrates by a vacuum injection method, and the injection port was sealed with a sealing agent to produce a liquid crystal display device.

(Evaluation of Examples and Comparative Examples)
The following items were evaluated. The results are shown in Tables 1 to 4 below.

(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 in the portion where the spacer particles were arranged, and the result was taken as the distribution density.

(Average number of spacer particles)
An average value of the number of spacer particles aggregated per one place was measured within a range of 1 mm ² and used as an average number of spacer particles. In Tables 1 to 4, the “−” mark indicates that measurement is not possible because the spacer particles are not aggregated.

(Discharge state after 1 hour)
The discharge state when the spacer particle dispersion was introduced into the ink chamber of the ink jet apparatus and then left to discharge for 1 hour was determined according to the following criteria.
○: Ejected from all nozzles.
Δ: Undischarged nozzle was less than 3%.
X: Undischarged nozzle was 3% or more.

(Spacer particle placement accuracy)
The arrangement state of the spacer particles after the droplets were dried was determined according to the following criteria.
A: Most of the spacer particles were in the region corresponding to the non-pixel region.
(Triangle | delta): Some spacer particles protruded from the area | region corresponding to a non-pixel area | region.
X: Many spacer particles protruded from the region corresponding to the non-pixel region.

(Spacer particle existence range)
As shown in FIG. 9, parallel lines are drawn at equal intervals on both sides from the center of the black matrix or the corresponding part, and between the parallel lines where the number of spacer particles of 95% or more exists between the two parallel lines. Was defined as the spacer particle existence range.

(Display quality)
The display image quality of the liquid crystal display device was observed and judged according to the following criteria.
A: Almost no spacer particles were observed in the display area, and no light omission was caused by the spacer particles.
Δ: Spacer particles were slightly observed in the display area, and light leakage due to the spacer particles was observed.
X: Spacer particles were observed, and there was light leakage due to the spacer particles.

Tables 5 and 6 below show the boiling point, surface tension, viscosity, specific gravity, and receding contact angle of each solvent with respect to the alignment film, in the examples and comparative examples.

As shown in Tables 1 to 3, in the liquid crystal display device of the example, the spacer particles were accurately arranged in the non-pixel region, and the display image quality was excellent. On the other hand, as shown in Table 4, in the liquid crystal display device of the comparative example, the spacer particle dispersion liquid may not be discharged stably. Further, the spacer particles are arranged even in the non-pixel region, and the display image quality is inferior.

(Example 27)
300 parts by weight of ethanol is mixed with 100 parts by weight of a mixed monomer consisting of 10 parts by weight of methyl methacrylate, 60 parts by weight of hydroxyethyl methacrylate, 10 parts by weight of polyethylene glycol methacrylate (molecular weight 400), 10 parts by weight of glycidyl methacrylate and 10 parts by weight of methacrylic acid. Into a separable flask, and purged with nitrogen, 10 parts by weight of a 10% by weight ethanol solution of an oil-soluble azo polymerization initiator (trade name “V-65”, manufactured by Wako Pure Chemical Industries, Ltd.) The polymerization reaction was performed at 65 ° C. while dropping over 1 hour. Thereafter, 200 parts by weight of ethylene glycol was added, the pressure was reduced at 40 ° C., ethanol was removed, and an adhesive component solution A in which the solvent was replaced with ethylene glycol was obtained.
A spacer particle dispersion was obtained in the same manner as in Example 1 except that the adhesive component A was added to the solvent so as to be 0.1% by weight.

(Comparative Example 6)
A spacer particle dispersion was obtained in the same manner as in Comparative Example 1 except that the adhesive component solution A obtained in Example 27 was added to the solvent so as to be 0.1% by weight.

(Evaluation)
After removing the agglomerates by filtering the spacer particle dispersion prepared in Example 27 for comparison with Example 27 and the spacer particle dispersion obtained in Comparative Example 6 through a stainless mesh (aperture 10 μm). In an inkjet device with a nozzle of 50 μm in diameter at the tip of a piezo head, aiming at the position corresponding to the black matrix of the color filter substrate of the TFT array substrate, every other vertical line above the vertical line The droplets of the spacer particle dispersion were discharged at intervals of 110 μm, and liquid crystal spacers were arranged at a pitch of 110 μm in length × 150 μm in width. The distance between the nozzle (head surface) and the substrate during ejection was 0.5 mm, and a double pulse method was used. The scattering density of the spacer particles thus arranged was 180 particles / mm ² .
After confirming that the spacer dispersion discharged on the substrate on the stage was completely dried by visual observation, the dispersion was further heated to 150 ° C. in order to remove the remaining dispersion medium and fix the spacer particles to the substrate. It was transferred to a hot plate, heated, allowed to stand for 15 minutes, and then naturally cooled to room temperature.

The number of spacer particles in the range of 1.0 mm ² before and after applying air with an air gun was measured on the TFT array substrate on which the spacer particles were arranged, and the ratio of the remaining spacer particles was determined.
In addition, as air blowing conditions at this time, air blowing pressures of 5 kg / cm ² and 10 kg / cm ² , a nozzle diameter of 2 mm, a vertical distance of 5 mm, and a time of 15 seconds were used.
The results are shown in Table 7.

Moreover, the presence range of the adhesive after the spacer particle dispersion liquid discharged to the substrate on the stage was dried was measured by visual observation using a microscope. In the case of an irregular shape, the maximum diameter (major diameter) was used.
Further, in the same manner as in Example 1, a liquid crystal display device was prepared using the spacer particle dispersion prepared in Example 27 and Comparative Example 6, and the display quality was evaluated. The results are shown in Table 7. In Table 7, “◯” indicates that the display quality was sufficient, and “X” indicates that the display quality was insufficient.

As shown in Table 7, by adding the adhesive component A containing a hydrophilic adhesive to the spacer particle dispersion prepared in Example 1, the fixing force of the spacer particles after placement is dramatically improved. Can do.
Further, the spacer particle dispersion prepared in Comparative Example 6 has a high adhering force, but the adhesive spread, and thus unevenness due to the adhesive occurred and the display quality deteriorated.

Method for manufacturing liquid crystal display device capable of arranging spacer particles with high accuracy in region corresponding to non-pixel region on substrate using ink jet device, and liquid crystal display obtained by method for manufacturing liquid crystal display device Apparatus and spacer particle dispersion can be provided.

DESCRIPTION OF SYMBOLS 1 ... Liquid crystal display device 2 ... 1st board | substrate 2A ... Transparent substrate 3 ... 2nd board | substrate 3A ... Transparent substrate 4 ... Black matrix 5 ... Color filter 6 ... Overcoat layer 7 ... ITO transparent electrode 8 ... Alignment film 9 ... Wiring DESCRIPTION OF SYMBOLS 10 ... ITO transparent electrode 11 ... Orientation film 11a ... Raised part 21 ... Meniscus 22 ... Spacer particle 23 ... Spacer particle dispersion 31 ... Spacer particle 32 ... Convex part 33 ... Concave part 51 ... Color filter substrate 52 ... Transparent substrate 53 ... Black matrix 54 ... Color filter 55 ... Overcoat layer 56 ... ITO transparent electrode 57 ... Alignment film 61 ... TFT array model substrate 62 ... Transparent substrate 63 ... Step 64 ... ITO transparent electrode 65 ... Alignment film 100 ... Head 101 ... Ink chamber 102 ... Ink Chamber 103 ... Discharge surface 104 ... Nozzle hole 105 ... Temperature control means 106 ... Ezo element

Claims (2)

A spacer particle dispersion that is discharged onto a substrate of a liquid crystal display element using an inkjet device and is used to dispose spacer particles on the substrate,
The spacer particle dispersion has a surface tension at 20 ° C. of 25 to 50 mN / m,
In the dispersion of spacer particles excluding the spacer particles, a solvent having a boiling point of 200 ° C. or higher and a surface tension of 20 m ° C. or higher is 1% by weight or higher, a boiling point of less than 150 ° C. and 20 ° C. A spacer particle dispersion comprising 1.5 to 50% by weight of a solvent having a surface tension of less than 28 mN / m . The solvent having a boiling point of 200 ° C. or more and a surface tension at 20 ° C. of 42 mN / m or more is at least one selected from the group consisting of 1,3-propanediol, 1,4-butanediol and glycerin. The spacer particle dispersion according to claim 1.

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