JP2005037721A - Spacer dispersion liquid for manufacturing liquid crystal display - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a spacer dispersion liquid for manufacturing a liquid crystal display by which spacers can be disposed with high accuracy on a non-display part of a substrate of the liquid crystal display by an ink jet method and light leakage or the like caused by the spacers is eliminated and excellent display quality is developed by strongly sticking the spacers to the non-display part. <P>SOLUTION: In the spacer dispersion liquid for manufacturing the liquid crystal display wherein the spacers are disposed in optional positions on the substrate by the ink jet method, the spacer dispersed in the spacer dispersion liquid is a composite particle wherein resin fine particles exist on the surface of a mother particle. The resin fine particles are preferably hydrophilic resin fine particles. The composite particle is preferably formed by making the resin fine particles having ionic groups adhere onto the surface of the mother particle in a liquid phase. Further preferably, the surface of the mother particle has ionic groups. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a spacer dispersion liquid for manufacturing a liquid crystal display device in which spacers are arranged at arbitrary positions on a substrate by an inkjet method.

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

  In a conventional method for manufacturing a liquid crystal display device, spacers are arranged on the pixel electrode, that is, the display portion (pixel region) of the liquid crystal display device in order to distribute the spacers randomly and uniformly on the substrate on which the pixel electrodes are formed. End up. The spacer is generally made of synthetic resin or glass. When the spacer is arranged on the pixel electrode, the phenomenon that the polarization is disturbed and the polarization is lost, so-called depolarization phenomenon occurs, and the spacer portion is The problem of causing light leakage occurs. In addition, the alignment of the liquid crystal on the spacer surface is disturbed, thereby causing a problem that light is lost and the contrast and color tone are lowered to deteriorate the display quality. In a TFT liquid crystal display device, a TFT element is disposed on a substrate. However, if a spacer is disposed on the TFT element, the TFT element may be damaged when pressure is applied to the substrate. Problems occur.

In order to suppress the occurrence of such problems due to the random and uniform distribution of spacers, it has been studied to dispose the spacers only under the light shielding layer (the portion that defines the pixel region). As a method of arranging the spacer only at a specific position in this way, for example, a color liquid crystal panel in which the spacer is arranged only at the position corresponding to the opening after the opening of the mask having the opening is aligned with the position to be arranged Is disclosed (for example, see Patent Document 1). Further, a liquid crystal display device in which a spacer is electrostatically attracted to a photosensitive member and then transferred to a transparent substrate and a manufacturing method thereof are disclosed (for example, refer to Patent Document 2).
However, these methods have a problem in that the alignment film on the substrate is easily damaged because the mask and the photoconductor are in direct contact with the substrate, and the display quality is deteriorated.

In addition, a method for manufacturing a liquid crystal display device is disclosed in which spacers are arranged at specific positions by electrostatic repulsion by applying spacers charged by applying a voltage to pixel electrodes on a substrate (for example, (See Patent Document 3).
However, since this method requires an electrode according to the pattern to be arranged, it is impossible to completely arrange the spacer at any position, and the type of applicable liquid crystal display device is restricted. There is.

On the other hand, in a liquid crystal display element in which a spacer and a liquid crystal are interposed in a gap portion between translucent electrode substrates on which transparent electrodes are deposited on opposite surfaces, the spacers are dispersedly arranged on the electrode substrate using an inkjet device. That is, a manufacturing method of a liquid crystal display device in which spacers are arranged by an ink jet printing method is disclosed (for example, see Patent Document 4). This method can be said to be an effective method because it does not directly contact the substrate itself as in the above-described method, and the spacer can be arranged in an arbitrary pattern at an arbitrary position.
However, on the other hand, since the spacer dispersion liquid to be discharged contains a spacer having a size of about 1 to 10 μm, in order to discharge straightly, the nozzle diameter of the head of the ink jet apparatus must be increased, As a result, the spacer dispersion liquid droplets discharged onto the substrate become large, and even if the spacer dispersion liquid is discharged aiming at the light shielding area on the substrate, the spacer dispersion liquid droplets are transferred from the light shielding area to the pixel area. There is a problem of protruding.

  In this case, the spacers are arranged up to the pixel region unless the droplets of the spacer dispersion liquid are dried and reduced around the landing point on the light shielding region and the spacers are collected to the landing point accordingly. Therefore, the desired effect of improving the image quality such as contrast and tone, that is, the display quality cannot be obtained. However, since the spacer is easy to move in the droplet or with the droplet during drying, the spacer is poorly fixed after the droplet is dried and the spacer is fixed to the substrate by heat treatment. That happened. If the adhesion of the spacer is poor, there is a problem that the spacer moves when liquid crystal is injected.

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

  In view of the above situation, the present invention can accurately arrange a spacer on a non-display portion of a liquid crystal display device substrate by an ink jet method, and is firmly fixed, so that there is no light leakage due to the spacer, and is excellent. It is an object of the present invention to provide a spacer dispersion liquid for manufacturing a liquid crystal display device capable of obtaining a liquid crystal display device exhibiting display quality.

  In order to achieve the above object, the invention according to claim 1 is a spacer dispersion liquid for manufacturing a liquid crystal display device in which spacers are arranged at arbitrary positions on a substrate by an ink jet method, and dispersed in the spacer dispersion liquid. Provided is a spacer dispersion liquid for manufacturing a liquid crystal display device in which the spacers are composite particles in which resin fine particles are present on the surface of mother particles.

  According to a second aspect of the present invention, there is provided a spacer dispersion liquid for manufacturing a liquid crystal display device according to the first aspect, wherein the resin fine particles are a hydrophilic resin.

  The invention according to claim 3 is the liquid crystal display device according to claim 1, wherein the composite particles are composite particles obtained by adhering resin fine particles having an ionic group in the liquid phase to the surface of the mother particles. A spacer dispersion for manufacturing is provided.

  According to a fourth aspect of the present invention, there is provided a spacer dispersion liquid for manufacturing a liquid crystal display device according to the third aspect, wherein the surface of the mother particle has an ionic group.

  In the invention of claim 5, the resin fine particles having an ionic group have a functional group (a) that reacts with the mother particle, and the mother particle also has a functional group that reacts with the functional group (a). A spacer dispersion for producing a liquid crystal display device according to claim 3 or 4, which has a group (b).

  According to a sixth aspect of the invention, the resin fine particles having an ionic group are resin fine particles that are crosslinked or can be crosslinked later. Provide liquid.

Details of the present invention will be described below.
The spacer dispersion liquid for manufacturing a liquid crystal display device of the present invention is a spacer dispersion liquid for manufacturing a liquid crystal display device (hereinafter, also simply referred to as “spacer dispersion liquid”) in which spacers are arranged at arbitrary positions on a substrate by an inkjet method. ).

[Spacer]
The spacer dispersed in the spacer dispersion liquid of the present invention is a composite particle in which resin fine particles are present on the surface of the mother particle.
The base particles of the composite particles are not particularly limited, and may be organic particles such as inorganic particles or organic polymer particles such as silica particles, and the resin particles of the composite particles are not particularly limited, Any material made of a resin such as organic polymer particles may be used. Among them, it has a suitable hardness that does not damage the alignment film formed on the substrate of the liquid crystal display device, can easily follow the change in thickness due to thermal expansion and contraction, and the movement of the spacer within the cell is relatively Organic polymer particles are preferably used for both the mother particles and the resin fine particles because they have advantages such as few.

  It does not specifically limit as a material which comprises the said mother particle, A conventionally well-known organic material or an inorganic material can be used.

The organic material is not particularly limited, and usually a resin composed of a monofunctional monomer and a polyfunctional monomer is used in view of strength and the like. At this time, the blending amount of the polyfunctional monomer is preferably 80% by weight or less. When the compounding quantity of a polyfunctional monomer exceeds 80 weight%, the intensity | strength and hardness of resin obtained may become high too much.
For example, when organic polymer particles are used as the mother particles, the resin is used. Hereinafter, this resin is also referred to as “resin constituting the mother particle”.

  Examples of the monofunctional monomer include olefins such as ethylene, propylene, butylene, and methylpentene and derivatives thereof; styrene such as styrene, α-methylstyrene, p-methylstyrene, p-chlorostyrene, and chloromethylstyrene. Derivatives; vinyl esters such as vinyl fluoride, vinyl chloride, vinyl acetate and vinyl propionate; unsaturated nitriles such as acrylonitrile; methyl (meth) acrylate, ethyl (meth) acrylate, butyl (meth) acrylate, Examples include (meth) acrylic acid esters such as 2-ethylhexyl (meth) acrylate, stearyl (meth) acrylate, ethylene glycol (meth) acrylate, and cyclohexyl (meth) acrylate. These monofunctional monomers may be used alone or in combination of two or more. Here, for example, “(meth) acryl” means “acryl” or “methacryl”.

  Examples of the polyfunctional monomer include divinylbenzene, 1,6-hexanediol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, tetramethylolmethanetri (meth) acrylate, tetramethylolpropanetetra (meta ) Acrylate, diallyl phthalate and its isomer, triallyl isocyanurate and its derivative, trimethylolpropane tri (meth) acrylate and its derivative, pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol hexa (Meth) acrylate and derivatives thereof, polyethylene glycol di (meth) acrylate such as ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate Polypropylene glycol di (meth) acrylate such as relate, polytetramethylene glycol di (meth) acrylate, neopentyl glycol di (meth) acrylate, 1,3-butylene glycol di (meth) acrylate, 2,2-bis [4- (Methacryloxyethoxy) phenyl] propanedi (meth) acrylate, 2,2-hydrogenated bis [4- (acryloxypolyethoxy) phenyl] propanedi (meth) acrylate, 2,2-bis [4- (acryloxyethoxypoly) Propoxy) phenyl] propane di (meth) acrylate, diallyl phthalate and isomers thereof, triallyl isocyanurate and derivatives thereof, triallyl isocyanate, benzoguanamine and the like. These polyfunctional monomers may be used alone or in combination of two or more.

  Examples of the resin composed of the monofunctional monomer include, in addition to the polymer using the monofunctional monomer, polyolefins such as polyethylene and polybutadiene; polystyrene, poly (meth) acrylic acid, poly (meth) acrylic acid. Ester, polyvinyl alcohol, polyimide, polyamide, (un) saturated polyester, polyethylene terephthalate, polysulfone, polyphenylene oxide, polyacetal, polyimide resin, polyamide imide, polyether ketone, polyether sulfone, epoxy resin, phenol resin, melamine resin, benzoguanamine Resin, silicone resin, polyester, nylon, polyurethane, polytetrafluoroethylene, acrylonitrile / styrene resin, styrene / butadiene resin, ABS resin, polyamide resin, Polycarbonate, polyphenylene oxide, sugars, starches, cellulose, condensate mainly containing polypeptide such as, polymers and the like. These may be used alone or in combination of two or more.

  Examples of the resin composed of the monofunctional monomer and the polyfunctional monomer include a polymer using the monofunctional monomer and the polyfunctional monomer.

  It does not specifically limit as said inorganic material, For example, a metal, a metal oxide, a silica etc. are mentioned. In addition, the mother particle may have a composite structure of the organic material and the inorganic material.

  As the resin constituting the resin fine particles in the present invention, the resins described for the resin constituting the mother particles can be used. The said resin may be used independently and may use 2 or more types together. Hereinafter, this resin is also referred to as “resin constituting resin fine particles”.

  Among the resins constituting the resin fine particles, a resin obtained by copolymerizing a monomer having a vinyl group is preferably used. The monomer having a vinyl group is appropriately selected from the monofunctional monomers described for the resin constituting the mother particle.

  The resin fine particles in the present invention are preferably hydrophilic resins in order to enhance the dispersibility of the composite particles. That is, as will be described later, a hydrophilic solvent is preferably used as a medium for dispersing the composite particles in the spacer dispersion liquid in which the composite particles are dispersed so that the composite particles can be easily discharged by an ink jet method. The fine particles are also preferably hydrophilic resins.

  In order to make the resin fine particles hydrophilic, the resin constituting the resin fine particles is made of a resin having a hydrophilic property such as polyvinyl alcohol or a crosslinked product thereof, or such a hydrophilic resin is used. Or a polymer obtained by polymerizing a monomer containing a hydroxyl group, a carboxyl group, an amino group or an ethylene glycol group as the polymerizable monomer, or an ionic group described later. What is necessary is just to give.

The surface of the mother particle in the present invention preferably has an ionic group such as an anionic group or a cationic group.
In order to impart an ionic group to the mother particle, a functional group is usually introduced. Examples of the method for introducing the functional group include a method in which an ionic surfactant is adsorbed on the surface of a mother particle made of resin, for example, or a method in which an ionic monomer is copolymerized when the mother particle is polymerized. Preferably used.

  In the case of adsorbing an ionic surfactant on the surface of the mother particle, examples of the anionic surfactant include alkyl sulfates such as sodium alkyl sulfate and ammonium alkyl sulfate; sodium alkyl sulfonate and ammonium alkyl sulfonate. And alkyl sulfonates.

  When an ionic monomer is copolymerized at the time of polymerization of the mother particles, examples of the anionic monomer include polymerization of acrylic acid, methacrylic acid, itaconic acid, fumaric acid, maleic acid, maleic anhydride, etc. Carboxylic acid having a polymerizable unsaturated bond; phosphate ester having a polymerizable unsaturated bond; sulfonic acid ester having a polymerizable unsaturated bond; sulfonium salt having a polymerizable unsaturated bond. These anionic monomers may be used independently and 2 or more types may be used together.

  Examples of the cationic surfactant for adsorbing the ionic surfactant on the surface of the mother particle include aliphatic amine salts, benzalkonium salts, pyridinium salts, and imidazolinium salts.

  Examples of the cationic monomer in the case of copolymerizing an ionic monomer at the time of polymerization of the mother particles include a polymerizable group such as dimethylaminoethyl methacrylate quaternary salt and diethylaminoethyl methacrylate quaternary salt. Examples include salts of amines; salts of nitrogen-containing aromatic compounds having a polymerizable group such as vinylpyridine; sulfonium salts having a polymerizable group such as phenyldimethylsulfonium methylsulfate methacrylate.

  Among these, a method of copolymerizing an ionic monomer at the time of polymerization of the mother particle is more preferable because it has an advantage that an ionic group is fixed to the mother particle and there is no elimination.

  The resin fine particles in the present invention also preferably have an anionic group or an ionic group of a cationic group. These can be the same as the ionic groups used when the ionic groups are introduced into the mother particles. The method of introducing is the same. The resin fine particles adhere to the mother particles through this ionic group.

In the present invention, resin fine particles having an ionic group have a functional group (a) that reacts with the mother particle, and the mother particle also has a functional group (b) that reacts with the functional group (a). It is preferable to have.
If the base particles have a functional group (b) that reacts with the functional group (a) present in the resin fine particles, the resin fine particles can be firmly bonded to the mother particles.

The functional group (a) and the functional group (b) are appropriately selected depending on the type of reaction, and are imparted to each particle.
Examples of the reaction include urethane reaction (isocyanate group and hydroxyl group, amino group or carboxyl group), ester reaction (carboxyl group or acid anhydride and hydroxyl group or amino group), epoxy reaction (epoxy group and amino group, or both Particles have epoxy groups and react with acid catalyst), oxetane reaction (oxetane group and amino group, or both particles have oxetane group and react with acid catalyst), imine reaction (imine (aziridine) group and carboxyl group) Oxazoline reaction (oxazoline group and carboxyl group or thiol group, etc.), condensation reaction of acrylol (both particles have an acrylol group and condensate upon heating), etc., and the functional group (a) and functional group (b Examples of the combination of) include the combinations shown in the above reactions.

  As a method for imparting these functional groups to the mother particles or resin fine particles, a method of copolymerizing monomers having these functional groups at the time of polymerization of the mother particles or resin fine particles, when preparing the mother particles or resin fine particles. And a method of mixing polymers having these functional groups and incorporating those functional groups into the particles.

  Examples of the monomer having a functional group include methacryloyloxyethyl isocyanate for isocyanate groups, 2-hydroxyethyl (meth) acrylate for hydroxyl groups, aminoethyl (meth) acrylate for carboxyl groups, carboxyl Group (meth) acrylic acid, acid anhydride maleic acid, epoxy group glycidyl (meth) acrylate, thiol group mercaptoethyl (meth) acrylate, acrylol group N- Examples of the butoxymethylacrylamide and oxazoline group include 2-isopropenyl-2-oxazoline.

  Examples of the polymer having the functional group include polyvinyl alcohol for a hydroxyl group, polyacrylic acid for a carboxyl group, and N, N′-hexamethylene-1,6-bis (1-aziridine for an imine group. Carboxamide) and the like.

The resin fine particles having an ionic group in the present invention are preferably resin fine particles that are crosslinked or can be crosslinked later in order to impart solvent resistance.
In order to make the resin fine particles cross-linkable or cross-linkable, for example, it is obtained by copolymerizing a monomer having cross-linkability. Examples of the crosslinkable monomer include those that crosslink at the time of copolymerization such as the polyfunctional monomer described in the resin constituting the mother particle, and polymerizable monomers having an epoxy group or an acrylol group. As described above, there may be mentioned those which are crosslinked after copolymerization.

  Specifically, in order to assume that the resin fine particles are cross-linked, for example, polyfunctional monomers such as divinylbenzene and polyethylene glycol di (meth) acrylate are used and cross-linked at the time of copolymerization. In order to make the resin fine particles capable of being crosslinked later, a polymerizable monomer such as glycidyl (meth) acrylate having an epoxy group or N-butoxymethylacrylamide having an acrylol group is used. When a polymerizable monomer having an epoxy group or an acrylol group is used, it is post-crosslinked by heat or the like after the resin fine particles are obtained. In consideration of stability and particle size variation when polymerizing the resin fine particles, it is preferable to copolymerize a post-crosslinkable monomer and post-crosslink.

  In order to impart adhesiveness to the resin fine particles, a monomer having a low glass transition point may be copolymerized. Examples of the monomer having a low glass transition point include butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, stearyl (meth) acrylate, and the like.

  The particle diameter of the mother particles may be appropriately determined depending on the use of the obtained composite particles, but when the obtained composite particles are used as a spacer of a display element, it is preferably 0.5 to 100 μm, Especially, when using as a spacer of a liquid crystal display device, it is more preferable that it is 1-10 micrometers.

The particle diameter of the resin fine particles may be appropriately determined depending on the particle diameter of the mother particles, the intended use of the obtained composite particles, and the coverage of the mother particles with the resin fine particles.
For example, when the obtained composite particles are used as adhesive particles, the particle diameter of the resin fine particles is preferably 1/10 or less of the particle diameter of the mother particles. If it exceeds 1/10, the particle diameter of the composite particles becomes too large, and the effect of using the mother particles cannot be expected. Moreover, when using the obtained composite particle | grain as an adhesive spacer for liquid crystal display devices, it is preferable that the particle diameter of the said resin fine particle is 5-1000 nm. If the thickness is less than 5 nm, the adhesiveness may be insufficient, and if it exceeds 1000 nm, the pressure required for pressure bonding may increase or the gap accuracy may decrease. More preferably, it is 10-500 nm.

  The particle diameters of the resin fine particles may not be equal, but the obtained composite particles can be used as spacers for liquid crystal display devices to strictly control the gap accuracy so as to eliminate display defects or to coat the mother particles with resin fine particles. When the ratio is made uniform, the variation coefficient of the particle diameter representing the particle diameter distribution (CV value: a value obtained by dividing the standard deviation of the particle diameter distribution by the average particle diameter as a percentage) may be 20% or less. preferable. More preferably, it is 1 to 10%.

  The method for producing the mother particles and the resin fine particles can be a conventionally known method and is not particularly limited. For example, suspension polymerization method, seed polymerization method, dispersion polymerization method, soap-free precipitation polymerization method, miniemulsion Examples thereof include a polymerization method, an emulsion polymerization method, a phase inversion emulsion polymerization method, and a micro suspension polymerization method. The suspension polymerization method has a relatively wide particle size distribution and can obtain polydisperse particles, and is therefore suitable for the purpose of producing particles of various types. However, when particles by suspension polymerization are used as spacers, it is preferable to classify and use those having a desired particle size or particle size distribution. In addition, the seed polymerization method, dispersion polymerization method, and soap-free precipitation polymerization method do not require classification operation and can obtain monodisperse particles, so that they are suitable for the purpose of producing a large amount of particles having a specific particle size. Yes.

In the polymerization, a dispersion medium and a polymerization initiator are used.
Examples of the polymerization initiator include benzoyl peroxide, lauroyl peroxide, orthochlorobenzoyl peroxide, orthomethoxybenzoyl peroxide, 3,5,5-trimethylhexanoyl peroxide, t-butylperoxy-2-ethylhexa Organic peroxides such as noate and di-t-butyl peroxide; azo compounds such as azobisisobutyronitrile, azobiscyclohexacarbonitrile, and azobis (2,4-dimethylvaleronitrile) . In addition, the usage-amount of the said polymerization initiator has a preferable 0.1-10 weight part with respect to 100 weight part of said monomers.

  The suspension polymerization method uses a monomer poor solvent as a medium, and a monomer composition comprising a monomer and a polymerization initiator in the medium so as to have a desired particle size and particle size distribution. In this method, the polymer is dispersed and polymerized. As the medium (poor solvent) in the suspension polymerization, a medium obtained by adding a dispersion stabilizer to water is usually used. Examples of the dispersion stabilizer include water-soluble polymers such as polyvinyl alcohol, polyvinyl pyrrolidone, methyl cellulose, ethyl cellulose, polyacrylic acid, polyacrylamide, and polyethylene oxide. Nonionic or ionic surfactants are also used as appropriate.

  The polymerization conditions for suspension polymerization may be appropriately determined depending on the type of polymerization initiator and monomer to be used, and are not particularly limited. Usually, the polymerization temperature is 50 to 80 ° C. The time is preferably 3 to 24 hours.

  The seed polymerization method is a polymerization method in which monodisperse seed particles produced by a soap-free polymerization method or an emulsion polymerization method are further expanded to a target particle diameter by absorbing a monomer. The monomer used for the seed particles is not particularly limited, but in order to suppress phase separation during seed polymerization, a monomer approximate to the monomer used during seed polymerization is preferably used. Among them, styrene and its derivatives are more preferably used because the monodispersity of the particle system distribution is good.

  Since the particle size distribution of the seed particles is reflected in the particle size distribution after seed polymerization, it is preferably monodispersed as much as possible, and is preferably 5% or less as the CV value. Since phase separation with seed particles is likely to occur during seed polymerization, it is preferable that the monomer absorbed by the seed particles during seed polymerization is as close as possible to the monomer used to prepare the seed particles. . For example, when the seed particles are made of a styrene resin, the monomer absorbed by the seed particles is preferably an aromatic divinyl monomer, and when the seed particles are made of an acrylic resin, the single particles absorbed by the seed particles are preferable. The monomer is preferably an acrylic multivinyl monomer.

  In the seed polymerization, a dispersion stabilizer may be used as necessary. Examples of the dispersion stabilizer include water-soluble polymers such as polyvinyl alcohol, polyvinyl pyrrolidone, methyl cellulose, ethyl cellulose, polyacrylic acid, polyacrylamide, and polyethylene oxide. Nonionic or ionic surfactants are also used as appropriate.

  In the seed polymerization, the amount of the monomer added to the seed particles is not particularly limited, but is preferably 20 to 100 parts by weight with respect to 1 part by weight of the seed particles. If the addition amount of the monomer with respect to 1 part by weight of the seed particles is less than 20 parts by weight, the breaking strength of the finally formed crosslinked particles may not be sufficient, and the addition amount of the monomer with respect to 1 part by weight of the seed particles is If the amount exceeds 100 parts by weight, coalescence of particles occurs during seed polymerization and the particle size distribution may be widened, which is not preferable.

  The dispersion polymerization method is a polymer produced by polymerizing with a poor solvent that dissolves the monomer but not the produced polymer as a medium, and adding a polymer dispersion stabilizer to this polymerization system. Is precipitated in the form of particles. In general, when a monomer containing a crosslinkable monomer is polymerized by a dispersion polymerization method, particle aggregation is likely to occur, and it is difficult to stably obtain monodispersed crosslinked particles, but by selecting polymerization conditions, It becomes possible to stably polymerize a monomer containing a crosslinkable monomer.

  The content of the crosslinkable monomer in the monomer containing the crosslinkable monomer is not particularly limited, but considers the aggregation of particles during dispersion polymerization and the strength of the resulting crosslinked particles. Then, it is preferable that it is 30 weight% or more. If the content of the crosslinkable monomer in the monomer containing the crosslinkable monomer is less than 30% by weight, the surface of the particles generated during the polymerization becomes soft in the medium. Adhesion may occur, and the particle size distribution of the resulting crosslinked particles may spread to an unfavorable level or may become an aggregate. Moreover, even if the monodispersibility is maintained, the crosslink density is lowered, and the fracture strength necessary for the spacer may not be sufficiently obtained.

  The medium in the dispersion polymerization is appropriately determined depending on the monomer used, and generally suitable organic solvents include, for example, alcohols, cellosolves, ketones, hydrocarbons, and the like. These can be used alone or as a mixed solvent with other organic solvents, water, or the like which are compatible with each other. Specifically, examples of suitable organic solvents include alcohols such as acetonitrile, N, N-dimethylformamide, dimethyl sulfoxide, ethyl acetate, methanol, ethanol, and propanol; cellosolves such as methyl cellosolve and ethyl cellosolve; acetone , Ketones such as methyl ethyl ketone, methyl butyl ketone and 2-butanone.

  In order to obtain the composite particles in the present invention, the resin fine particles are present on the surface of the base particles, for example, electrostatic interaction, a dry blend method using a high-speed stirrer or a hybridizer, a melt dispersion cooling method, a dissolution method, etc. Examples thereof include a dispersion drying method, a spray drying method, an interfacial polymerization method, and a heteroaggregation method.

The composite particles in the present invention are preferably particles obtained by adhering resin fine particles having an ionic group in the liquid phase to the surface of the mother particles.
Among these, composite particles obtained by the hetero-aggregation method in which resin particles are aggregated on the surface of the mother particles by electrostatic force in an aqueous medium or an organic solvent have the resin particles uniformly and rapidly attached to the surface of the mother particles. In addition, it is preferable because the load on the mother particles is reduced because an excessive pressure is not applied and the temperature of the entire system does not increase.

  Examples of the aqueous medium used in the heteroaggregation method include water or a mixed solvent of water and an organic solvent soluble in water. The organic solvent soluble in water is not particularly limited as long as it does not dissolve the resin fine particles, and a known organic solvent can be used.

  It is preferable that the surfactant is not contained in the aqueous medium. When a large amount of a surfactant is contained, heteroaggregation hardly occurs because the particles in the system are stably dispersed. The amount of the surfactant is preferably 0.1% by weight or less in the aqueous medium.

  The composite particles preferably have a surface coverage of 5% or more of the mother particles with resin fine particles. If it is less than 5%, the effect of the coating becomes weak. In the present invention in which the obtained composite particles are used as spacers, the coverage is preferably 10 to 100%. If the coverage is less than 10%, the coating may be insufficient, and the adhesion of the spacer to the substrate may not be exhibited sufficiently.

  The coverage can be controlled by the charge density on the surface of the resin fine particles, the pH and ionic strength of water and / or an organic solvent, and the like. In order to increase the coverage, for example, a method of adding a salt or an organic solvent to the aqueous medium can be used, and sodium chloride is preferably added.

  Since the composite particles used in the present invention are used as a spacer (gap material) of a liquid crystal display device, the composite particles preferably have a certain strength such as a compressive strength. When the compressive elastic modulus (10% K value) when the diameter of the composite particle is displaced by 10% is taken as an index indicating the compressive strength of the composite particle, the above-described compressive elastic modulus ( 10% K value) is preferably 2000 to 15000 MPa. If the compression elastic modulus (10% K value) of the composite particles is less than 2000 MPa, the spacer may be deformed by the press pressure when assembling the liquid crystal display device, making it difficult to produce an appropriate gap, exceeding 15000 MPa. When the spacer is incorporated in the liquid crystal display device, the alignment film on the substrate may be damaged to cause display abnormality.

The compression elastic modulus (10% K value) means a value measured by the following method in order to accurately grasp the hardness of the flexible composite particles.
[Measurement method of compression modulus (10% K value)]
For example, as described in JP-T-6-503180, a micro compression tester (model “PCT-200”, manufactured by Shimadzu Corporation) is used as a measuring device, and a cylindrical column made of diamond having a diameter of 50 μm is smooth. The composite particle is compressed at the end face, and the compression load when the diameter of the composite particle is displaced by 10% is obtained.

  The composite particles may be colored in order to improve contrast, which is one of the display qualities of the liquid crystal display device. The method for coloring the composite particles is not particularly limited. For example, a color treatment method using a colorant such as carbon black, a disperse dye, an acid dye, a basic dye, or a metal oxide, or on the surface of the composite particles. Examples thereof include a method of forming an organic film and then decomposing or carbonizing the organic film at a high temperature for coloring, and any coloring method may be employed. In addition, when the material itself which forms a composite particle is colored, you may use as it is, without performing a coloring process.

The composite particles may be further provided with an adhesive layer on the surface, or may be subjected to surface modification so as not to disturb the alignment of the liquid crystal around the composite particles when used in a liquid crystal display device.
The surface modification method is not particularly limited. For example, as disclosed in JP-A-1-247154, a method in which a resin is deposited on the spacer surface for modification, JP-A-9-113915. The method of modifying the surface by acting a compound that reacts with the functional group on the spacer surface as disclosed in Japanese Patent Application No. 11-223818, or the surface of the spacer as disclosed in Japanese Patent Application No. 2002-102848 In this method, the surface is modified by graft polymerization, and in particular, the surface modification layer is not peeled off or dissolved in the liquid crystal in the cell of the liquid crystal display device. The method of surface modification by forming a surface layer is preferable, and in particular, a high-density surface layer can be formed with a sufficient thickness. As disclosed in JP-A-9-113915, a method for surface modification by reacting an oxidant with a spacer having a reducing group on the surface, generating radicals on the spacer surface, and performing graft polymerization on the spacer surface Is more preferable.

[Spacer dispersion]
The spacer dispersion liquid of the present invention is obtained by dispersing the above-described spacer in a dispersion medium.
The dispersion medium is not particularly limited as long as it is a liquid at a temperature discharged from the nozzle of the head of the ink jet apparatus and can disperse the spacer. Of these, water and hydrophilic organic solvents are preferably used.

  Since some inkjet heads are suitable for aqueous dispersion media, when such a head is used, if the dispersion medium is a highly hydrophobic organic solvent, the members constituting the head are dispersed. Problems occur such as being eroded by the medium and part of the adhesive used for bonding the members eluting into the dispersion medium. Accordingly, the dispersion medium of the spacer dispersion liquid is preferably water or a hydrophilic organic solvent.

  Although it does not specifically limit as said water, For example, ion-exchange water, a pure water, ground water, a tap water, industrial water etc. are mentioned. These waters may be used alone or in combination of two or more.

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

  The dispersion medium in the present invention preferably contains a hydrophilic organic solvent having a boiling point of less than 100 ° C., and more preferably contains a hydrophilic organic solvent having a boiling point of 70 ° C. or more and less than 100 ° C. is there. In addition, the boiling point said by this invention means the boiling point on 1 atmosphere conditions.

  The hydrophilic organic solvent having a boiling point of less than 100 ° C. is not particularly limited, and examples thereof include lower monoalcohols such as ethanol, n-propanol, and 2-propanol, acetone, and the like. These hydrophilic organic solvents having a boiling point of less than 100 ° C. may be used alone or in combination of two or more.

  The hydrophilic organic solvent having a boiling point of less than 100 ° C. volatilizes at a relatively low temperature when the spacer dispersion liquid is discharged onto the substrate and dried. If the dispersion medium comes into contact with the alignment film at a high temperature, the alignment film may be contaminated and the display quality of the liquid crystal display device may be impaired. Therefore, the drying temperature cannot be increased too much. Therefore, it is preferable to use a hydrophilic organic solvent having a boiling point of less than 100 ° C. However, if the hydrophilic organic solvent having a boiling point of less than 100 ° C. is easily volatilized at room temperature, aggregated particles are likely to be generated during the production or storage of the spacer dispersion, or the spacer dispersion located near the nozzle of the inkjet device Since it becomes easy to dry and the discharge property by an inkjet apparatus is impaired, the hydrophilic organic solvent which tends to volatilize at room temperature is not preferable.

  The content of the hydrophilic organic solvent having a boiling point of less than 100 ° C. in the dispersion medium is not particularly limited, but is preferably 10 to 80% by weight.

  When the content of the hydrophilic organic solvent having a boiling point of less than 100 ° C. in the dispersion medium is less than 10% by weight, the above-mentioned effect due to the inclusion of the hydrophilic organic solvent having a boiling point of less than 100 ° C. cannot be obtained sufficiently. Conversely, if the content of the hydrophilic organic solvent having a boiling point in the dispersion medium of less than 100 ° C. exceeds 80% by weight, it becomes easy to dry during the production or storage of the spacer dispersion liquid, and aggregated particles are generated. In addition, the spacer dispersion near the nozzles of the ink jet apparatus may be excessively dried, and the discharge performance and discharge accuracy may be impaired.

  Moreover, it is preferable that the dispersion medium in the present invention contains a hydrophilic organic solvent having a boiling point of 150 ° C. or higher, more preferably a hydrophilic organic solvent having a boiling point of 150 to 200 ° C. is there.

  The hydrophilic organic solvent having a boiling point of 150 ° C. or higher is not particularly limited, and examples thereof include lower alcohol ethers such as ethylene glycol, ethylene glycol monomethyl ether, and ethylene glycol dimethyl ether. These hydrophilic organic solvents having a boiling point of 150 ° C. or higher may be used alone or in combination of two or more.

  The above-mentioned hydrophilic organic solvent having a boiling point of 150 ° C. or higher suppresses the generation of aggregated particles by drying during the production or storage of the spacer dispersion, or the spacer dispersion is excessively dried in the vicinity of the nozzle of the inkjet device. Thus, the discharge property and the discharge accuracy are suppressed from being impaired.

  The content of the hydrophilic organic solvent having a boiling point of 150 ° C. or higher in the dispersion medium is not particularly limited, but is preferably 0.1 to 80% by weight, more preferably 0.2 to 40% by weight. %.

  When the content of the hydrophilic organic solvent having a boiling point of 150 ° C. or higher in the dispersion medium is less than 0.1% by weight, the above-described effect due to the inclusion of the hydrophilic organic solvent having a boiling point of 150 ° C. or higher can be sufficiently obtained. On the contrary, when the content of the hydrophilic organic solvent having a boiling point in the dispersion medium of 150 ° C. or higher exceeds 80% by weight, the drying time of the spacer dispersion liquid becomes remarkably long, and the productivity is lowered. The alignment film may be contaminated and the display quality of the liquid crystal display device may be impaired.

  The hydrophilic organic solvent having a boiling point of less than 100 ° C. is not particularly limited, but the surface tension at 20 ° C. is preferably 25 mN / m or less. The hydrophilic organic solvent having a boiling point of 150 ° C. or higher is not particularly limited, but the surface tension at 20 ° C. is preferably 30 mN / m or higher.

  In general, an ink jet apparatus exhibits good ejection accuracy when the surface tension of a spacer dispersion liquid to be ejected is 20 to 50 mN / m at 20 ° C. On the other hand, a higher surface tension of the spacer dispersion liquid droplets discharged onto the substrate is suitable for moving the spacer during the drying process.

  When the surface tension at 20 ° C. of the hydrophilic organic solvent having a boiling point of less than 100 ° C. is 25 mN / m or less, the surface tension of the spacer dispersion liquid is relatively low at the time of discharge, so that good discharge accuracy is obtained. After landing on the substrate, it volatilizes prior to the other dispersion medium components in the spacer dispersion liquid, and the surface tension of the spacer dispersion liquid becomes high, so that the spacer can be easily moved during the drying process.

  In addition, when the surface tension of a hydrophilic organic solvent having a boiling point of 150 ° C. or higher at 20 ° C. is 30 mN / m or higher, water or a hydrophilic organic solvent having a lower boiling point after the spacer dispersion liquid droplets land on the substrate. Since the surface tension of the spacer dispersion liquid is kept high after evaporating, the movement of the spacer in the drying process is facilitated.

  The spacer dispersion liquid of the present invention is not particularly limited, but one or more of the above-mentioned various organic solvents are mixed so that the surface tension at 20 ° C. becomes [surface energy of substrate −5] to 50 mN / m. It is preferable to adjust to.

  When the surface tension of the spacer dispersion at 20 ° C. is less than [surface energy of the substrate −5] mN / m, the substrate is discharged onto the substrate even in the case of a substrate using an alignment film having strong hydrophobicity, that is, low surface energy. The contact angle of the spacer dispersion liquid droplets to the substrate cannot be increased, and the spacer dispersion liquid droplets wet and spread on the substrate, making it impossible to reduce the spacer spacing. On the other hand, if the surface tension of the spacer dispersion at 20 ° C. exceeds 50 mN / m, bubbles may remain in the nozzles of the ink jet apparatus, and the discharge may not be performed smoothly.

  Moreover, the spacer dispersion liquid of the present invention is not particularly limited, but the contact angle with the substrate surface is preferably 30 to 90 degrees.

  If the contact angle of the spacer dispersion liquid with the substrate surface is less than 30 degrees, the spacer dispersion liquid droplets discharged onto the substrate become wet and spread on the substrate, thereby reducing the spacing between the spacers. Conversely, if the contact angle of the spacer dispersion liquid with the substrate surface exceeds 90 degrees, the spacer dispersion liquid droplets move around the substrate with a slight vibration, and the spacer placement accuracy deteriorates. Or the adhesion of the spacer to the substrate surface may deteriorate.

  Furthermore, the spacer dispersion liquid of the present invention is not particularly limited, but the viscosity at the time of ejection is preferably 0.5 to 15 mPa · s, more preferably 5 to 10 mPa · s.

  If the viscosity at the time of discharging the spacer dispersion liquid is less than 0.5 mPa · s, it may be difficult to control the discharge amount, and stable discharge may not be possible. When the viscosity of the ink exceeds 15 mPa · s, it may be difficult to discharge with an ink jet apparatus. In order to make the viscosity at the time of discharging the spacer dispersion liquid within the above-mentioned preferable range, the temperature of the head of the ink jet apparatus is preferably cooled in a temperature range of −5 ° C. to 50 ° C. The liquid temperature at the time of discharging the spacer dispersion liquid may be adjusted.

  The solid content concentration of the spacer in the spacer dispersion of the present invention is not particularly limited, but is preferably 0.01 to 5% by weight, more preferably 0.1 to 2% by weight. .

  When the solid content concentration of the spacer in the spacer dispersion liquid is less than 0.01% by weight, an effective amount of spacer may not be contained in the discharged spacer dispersion liquid droplets, and conversely in the spacer dispersion liquid. If the solid content concentration of the spacer exceeds 5% by weight, the nozzle of the ink jet device is likely to be clogged, or the spacer content in the droplets of the discharged spacer dispersion becomes excessive, and the spacer in the drying process May be difficult to move.

  Moreover, in the spacer dispersion liquid of this invention, it is preferable that the said spacer is disperse | distributing to the said dispersion medium in the shape of a single particle. If the spacers are not dispersed in a single particle form in the dispersion medium and there are aggregates, the discharge properties and the discharge accuracy may be reduced, or the nozzles of the ink jet apparatus may be blocked.

  In the spacer dispersion liquid of the present invention, if necessary, for example, an adhesive imparting agent for improving the adhesive property, the dispersibility of the spacer is improved, the surface tension, the contact angle with the substrate surface , Surfactants (emulsifiers), viscosity modifiers, pH adjusters, antifoaming agents, antioxidants, thermal stability to improve physical properties such as viscosity to improve ejection accuracy and spacer mobility One kind or two or more kinds of various additives such as an agent, a light stabilizer, an ultraviolet absorber and a colorant may be added.

[Inkjet device]
Next, an ink jet apparatus that discharges the above-described spacer dispersion onto the substrate will be described.
The ink jet device according to the present invention is not particularly limited. For example, a piezo method in which a liquid is ejected from a nozzle by vibration of a piezo element, or a liquid is ejected from a nozzle by utilizing expansion of the liquid by rapid heating. Examples include a thermal method and a bubble jet (registered trademark) method in which a liquid is ejected from a nozzle by rapid heating of a heating element, and any type of ink jet apparatus may be used.

  The nozzle diameter of the inkjet apparatus is not particularly limited, but is 7 times or more the particle diameter of the composite particles (spacer), and preferably 150 μm or less. When the nozzle diameter of the inkjet device is less than 7 times the particle diameter of the composite particles, the nozzle diameter is usually smaller than the particle diameter of the spacer when a spacer dispersion containing a spacer having a particle diameter of about 1 to 10 μm is discharged. If the nozzle diameter of the inkjet device exceeds 150 μm, the droplet diameter of the discharged spacer dispersion liquid may be reduced. Since the diameter of the droplets that have landed on the substrate (landing diameter) increases, the spacer placement accuracy may become rough.

  The reason why the discharge accuracy of the spacer dispersion liquid decreases is explained as follows. 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 the ink is ejected from the ink chamber through the nozzle tip. The droplet discharge method includes a pulling method in which the meniscus (interface between ink and gas) at the tip of the nozzle is pulled in immediately before discharge, and the liquid is pushed out. Although there is a hitting method, in the general ink jet apparatus, the former hitting method is the mainstream because smaller droplets can be ejected.

  In the ejection of the spacer dispersion liquid of the present invention, the nozzle diameter of the ink jet apparatus is somewhat large and the ejection of small droplets is required, so this striking method is effective. On the other hand, in the case of the pulling method, the meniscus is drawn immediately before ejection, so when the nozzle diameter of the inkjet device is smaller than 7 times the particle size of the composite particles, if there is a spacer near the drawn meniscus, the meniscus becomes axisymmetric Since the liquid is not drawn, when the spacer dispersion liquid is pushed out after the meniscus is drawn in, the liquid droplets do not move straight but are bent, which is not preferable. Conversely, when the nozzle diameter of the ink jet device is as large as more than 150 μm, the droplets to be ejected become large and the landing diameter also becomes large, which is not preferable because the spacer placement accuracy may become coarse.

  The amount of droplets of the spacer dispersion liquid ejected from the nozzles of the inkjet device is not particularly limited, but is preferably 10 to 80 pL. The method for controlling the droplet amount is not particularly limited, and examples thereof include a method for optimizing the nozzle diameter of the ink jet apparatus and a method for optimizing an electric signal for controlling the head of the ink jet apparatus. Any method may be adopted. In particular, when using a piezo-type ink jet apparatus, the latter method is preferably employed.

  A head in an ink jet apparatus is provided with a plurality of nozzles as described above in a fixed arrangement (for example, a plurality of 64 or 128, for example, at equal intervals in a direction orthogonal to the moving direction of the head). ing. In some cases, these are arranged in a plurality of rows such as two rows. Since the interval between the nozzles is restricted by the structure of the piezo element and the nozzle diameter, it is difficult to prepare a head for each of the discharge intervals when the spacer dispersion liquid is discharged onto the substrate other than this interval. Therefore, when the distance between the heads is smaller than the distance between the heads, a method of inclining (rotating) the head, which is usually arranged at a right angle to the scanning (moving) direction of the head, in a plane parallel to the substrate is maintained. It is preferable to adopt a method in which, when the interval is larger than the interval between the heads, it is preferable to adopt a method in which the ejection is performed only by a fixed nozzle, or the head is inclined, instead of ejecting by all nozzles.

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

[Spacer Dispersion Discharge Method and Droplet Landing Method]
The substrate to which the spacer dispersion liquid is discharged may be one that is generally used as a panel substrate of a liquid crystal display device, and is not particularly limited, but examples thereof include a glass substrate and a resin substrate. Any substrate may be used.

  These substrates are composed of a set of two, one of which is a pixel region (display portion) arranged according to a certain pattern and a light-shielding region (non-display portion) that defines the pixel region. Consists of. Specifically, the substrate is a color filter substrate, and pixel areas arranged according to a certain pattern are color filters, and these pixel areas are substantially light-transmissive metals such as chromium, carbon black, etc. The image is defined by a light-shielding region (black matrix) made of resin or the like dispersed.

  The method for manufacturing a liquid crystal display device according to the present invention uses an ink jet device at a portion having a low energy surface formed in advance in a light shielding region or a region corresponding to the light shielding region of at least one substrate constituting the liquid crystal display device. It is preferable that droplets of the spacer dispersion liquid are landed and the droplets of the spacer dispersion liquid are dried, so that the spacer is kept in the light shielding region or a region corresponding to the light shielding region.

  The region corresponding to the light-shielding region here means, for example, a black matrix if the substrate is a color filter substrate, and the other substrate (a TFT liquid crystal panel) in a set of two substrates. For example, when the TFT array substrate is overlapped with the substrate having the light shielding region, it also means a region on the other substrate corresponding to the light shielding region (a wiring portion or the like in the case of the TFT array substrate).

  The portion having the low energy surface may be formed in a light-blocking region of only one substrate or a region corresponding to the light-blocking region, or formed in a region corresponding to the light-blocking region or the light-blocking region of both substrates. May be. Further, the liquid droplets of the spacer dispersion liquid may be landed only on a light-shielding region of one substrate or a portion having a low energy surface formed in a region corresponding to the light-shielding region, You may make it land in the location which has the low energy surface formed in the area | region corresponded to a light-shielding area | region.

  The part having the low energy surface preferably has a surface energy (SE) of 45 mN / m or less, more preferably 40 mN / m or less.

  When the surface energy of the portion having the low energy surface exceeds 45 mN / m, as long as the spacer dispersion liquid having a surface tension that can be discharged by the ink jet apparatus is used, the droplet of the spacer dispersion liquid has the low energy surface. The liquid droplets do not easily shrink into the light-shielding region or the region corresponding to the light-shielding region, or the spacer in the droplet does not easily move to the light-shielding region or the region corresponding to the light-shielding region. Thus, the spacer may protrude from the light shielding region of the substrate or the region corresponding to the light shielding region.

  A method for forming such a portion having a low energy surface is not particularly limited. For example, a low energy such as a fluorine resin film or a silicone resin film made of a fluorine resin or a silicone resin is used. A method of applying a resin film having a surface, or an alignment film (usually a resin thin film having a thickness of 0.1 μm or less) itself provided on a substrate for regulating the alignment of liquid crystal molecules as a location having a low energy surface Among them, the manufacturing method of the liquid crystal display device is simplified, and the workability is also good. Therefore, it is preferable to adopt a method of using the alignment film itself as a portion having a low energy surface. . The method for forming the portion having the low energy surface may be used alone or a plurality of methods may be used in combination.

  A polyimide resin film is generally used for the alignment film. The polyimide resin film can be obtained by a method such as thermal polymerization after coating a polyamic acid soluble in an organic solvent, or drying after coating a soluble polyimide resin. Among these polyimide resin films, a polyimide resin film having a long main chain or side chain is particularly preferably used as a portion having a low energy surface.

  In order to control the alignment of the liquid crystal, the alignment film is rubbed on the surface after coating. As the dispersion medium of the spacer dispersion liquid, it is preferable to select and use a medium that does not contaminate the alignment film, such as permeating into the alignment film or dissolving the alignment film.

  The portion having a low energy surface made of the alignment film or the like may be partially formed in a light shielding region or a region corresponding to the light shielding region of at least one substrate, or a region corresponding to the light shielding region or the light shielding region. In consideration of a process such as patterning, it may be formed on the entire surface of the substrate.

  In the method for manufacturing a liquid crystal display device according to the present invention, a portion having the low energy surface is formed in a light shielding region or a region corresponding to the light shielding region of at least one substrate constituting the liquid crystal display device. It is preferable to discharge the spacer dispersion liquid aiming at the part having the surface and land the droplet of the spacer dispersion liquid on the part having the low energy surface. A step portion having a difference may be formed.

  By forming the stepped portion in the portion having the low energy surface, the droplet of the spacer dispersion liquid that has landed in the portion having the low energy surface is landed so as to include the stepped portion. Since the drying center of the droplet is artificially fixed to the step portion at the final stage of drying the droplet, after the droplet of the spacer dispersion liquid is dried, the spacer is removed from the step portion existing in the portion having the low energy surface. As a result, the spacers can be efficiently collected in a very limited position around the periphery, and as a result, the spacers can be more efficiently and more easily collected in the light shielding region of the substrate or the region corresponding to the light shielding region.

  The stepped portion is not particularly limited, and may be, for example, an unintentional uneven portion generated by wiring or the like provided on the substrate. It may be an uneven part intentionally provided to collect in the area corresponding to. That is, the step portion referred to in the present invention means a step portion between a concave portion or a convex portion and a flat portion (reference surface) in the surface uneven shape. The structure and shape of the stepped portion (uneven portion) may be any structure or shape, and is not particularly limited. Further, the structure below the surface is not particularly limited. Further, the stepped portion may be present in a portion having a low energy surface as a whole, or may be present in a state where a portion protrudes from a portion having a low energy surface.

  Specific examples of the stepped portion are not particularly limited. For example, a stepped portion by a gate electrode or a source electrode in a TFT array substrate in a TFT liquid crystal panel, a stepped portion by an array in the TFT array substrate, a color filter Examples include a step difference between image color filters on the black matrix on the substrate.

  In the method of manufacturing a liquid crystal display device according to the present invention, when the particle diameter of the spacer is D (μm) and the height difference of the stepped portion is B (μm), the height difference of the stepped portion is 0.01 <| B It is preferable to be within the range of | <0.95D. In addition, the height difference here means the height of the convex portion with respect to the flat portion (reference surface) when the step portion is a convex portion, and with respect to the flat portion (reference surface) when the step portion is a concave portion. It means the depth (lowness) of the recess.

  When the above | B | is less than 0.01 μm, a step portion is included in the droplet of the spacer dispersion liquid, and the dried spacers are more efficiently and more easily collected in the light shielding region or the region corresponding to the light shielding region. On the other hand, if | B | exceeds 0.95 Dμm, the effect of adjusting the gap of the substrate by the spacer may not be sufficiently obtained.

  If there is no stepped portion, even if the spacer dispersion liquid is ejected at a constant interval (S1 = S2) into a portion having a low energy surface, any part of the droplet end portion is somehow in the drying process. Even if the spacers after drying gather at one place in each place, the interval is not constant (L1 ≠ L2), and the spacers protrude into the pixel region. On the other hand, if there is a stepped part, even if any part of the liquid droplet edge is fixed for some reason during the drying process, the liquid is now removed at the stepped part as drying proceeds further. The drop end is fixed. Since the fixing force at this step portion is strong, the fixing of the liquid droplet end is released and finally dried so as to include the step portion, so the spacer after drying is at one place at each location. The intervals are almost constant (L1≈L2) and do not protrude into the pixel area.

  The position where the spacer after the drying finally remains is often the corner of the convex portion if the step portion is a convex portion, and often in the concave portion if the step portion is a concave portion.

  In addition, when a stepped portion is formed by wiring or the like, or when a stepped portion is formed by sandwiching a thin film such as an alignment film in the vicinity of the wiring or the like, since the metal exists, the spacer is surface-modified. In some cases or when a charge control agent is contained, it is considered that the spacer moves and is adsorbed to the portion of the droplet by electrostatic interaction, so-called electrostatic electrophoresis effect. In this case, change the metal species such as wiring, change the functional group of the compound used for surface modification, such as using an ionic functional group, adjust the type of the charge control agent, or For example, the spacers can be gathered electrostatically by applying a positive or negative voltage that does not damage the circuit to the wiring such as the source wiring or the gate wiring or the entire surface of the substrate.

  In the method for manufacturing a liquid crystal display device according to the present invention, it is preferable to discharge the spacer dispersion liquid onto the substrate at intervals equal to or greater than the following formula (1). The interval is the minimum interval between the droplets when the next droplet is ejected while the landed spacer dispersion droplet is not dried.

ここで、Ｄはスペーサの粒子径（μｍ）であり、θはスペーサ分散液と基板面との接触角である。

Here, D is the particle diameter (μm) of the spacer, and θ is the contact angle between the spacer dispersion and the substrate surface.

  If the nozzle diameter of the ink jet apparatus is not reduced when trying to eject at intervals less than the formula (1), the ejected droplet diameter (droplet amount) remains large, so the landing diameter also increases, and the droplets The coalescence occurs. When coalescence of droplets occurs, the aggregating direction of the spacers does not occur toward one place during the drying process, and as a result, the arrangement accuracy of the spacers after drying may deteriorate. In addition, if the nozzle diameter of the ink jet apparatus is reduced in order to reduce the discharged droplet diameter (droplet amount), the particle diameter of the spacer is relatively larger than the nozzle diameter, so the nozzle of the ink jet apparatus It becomes difficult to discharge the spacer dispersion liquid stably (always linearly in the same direction), and the landing position accuracy of the liquid droplets of the spacer dispersion liquid decreases due to bending of the flight. May happen.

As a result of discharging at intervals equal to or greater than the formula (1), the number of spacers arranged (spacer density) is usually preferably 50 to 350 / mm ² . Any pattern may be arranged in any part of the light-blocking area or the area corresponding to the light-blocking area by the black matrix or wiring as long as the spacer density is satisfied. In order to prevent the protrusion more effectively, for a color filter composed of a lattice-shaped light shielding region or a region corresponding to the light shielding region, it corresponds to a lattice-shaped light shielding region or light shielding region on one substrate. It is preferable to arrange with aiming at the lattice points of the region.

  Further, in this way, in order to eject the spacer dispersion liquid and land the droplets on the target position on the substrate, the head of the ink jet apparatus may be scanned (moved) once, or a plurality of times. It may be divided into two. In particular, when the interval at which the spacers are to be arranged is less than the formula (1), discharge is performed at an integral multiple of the interval, and after drying, the position is shifted by that amount and then discharged again. Or the like. Further, the scanning direction of the head of the ink jet apparatus may be changed alternately every time (reciprocal discharge), or may be discharged only when moving in one direction (unidirectional discharge).

  Further, as such an arrangement method, for example, the head of the ink jet apparatus is tilted so as to have an angle with a perpendicular to the substrate surface, and the discharge direction of the droplet of the spacer dispersion liquid is changed (usually parallel to the perpendicular to the substrate surface). Furthermore, by controlling the relative speed between the head and the substrate, the diameter of the droplets that land can be reduced, and the spacer can be more easily contained in the light shielding region or the region corresponding to the light shielding region.

[Drying method]
Next, a process of drying the dispersion medium in the spacer dispersion liquid droplets landed on the substrate will be described. The method for drying the dispersion medium in the droplets is not particularly limited, and may be performed, for example, as follows.

  In the drying, after the spacer dispersion liquid droplets discharged onto the substrate from the nozzles of the ink jet apparatus are dried, the spacer has a diameter smaller than the diameter of the spacer dispersion liquid droplets immediately after being discharged onto the substrate. It is preferable to dry so that it exists in a circle.

  Thus, in the drying process, the boiling point of the dispersion medium, the drying temperature, the drying time, the surface tension of the dispersion medium, the dispersion medium, in order to gather near the center of the spacer dispersion liquid droplets immediately after the spacers are discharged. It is important to set the contact angle with respect to the alignment film, the concentration of the spacer, and the like to appropriate conditions, but the drying conditions are particularly important.

  That is, it is preferable to dry with a certain time width so that the dispersion medium is not lost while the spacer moves on the substrate. For this reason, drying conditions that cause the dispersion medium to dry rapidly are not preferable. In addition, when the dispersion medium is in contact with the alignment film for a long time at a high temperature, the alignment film may be contaminated and the display quality of the liquid crystal display device may be impaired. In addition, if the dispersion medium easily evaporates at room temperature, the spacer dispersion near the nozzles of the ink jet device is likely to dry, resulting in a loss of ejection performance, or due to drying during manufacture of the spacer dispersion or storage in a storage tank. Since agglomeration of the spacer may occur, a dispersion medium that easily volatilizes at room temperature is not preferable. Further, even under conditions where the surface temperature of the substrate is relatively low, the productivity of the liquid crystal display device decreases when the drying time is remarkably prolonged, so that low temperature and long time drying conditions are also not preferable.

  In consideration of such constraints, the surface temperature of the substrate at the time when the spacer dispersion liquid droplets land on the substrate is not particularly limited, but it is most contained in the dispersion medium of the spacer dispersion liquid. The temperature is preferably 20 ° C. or more lower than the boiling point of the low boiling point dispersion medium component.

  When the surface temperature of the substrate is lower than the boiling point of the lowest-boiling point dispersion medium component contained in the dispersion medium of the spacer dispersion liquid by less than 20 ° C., the lowest-boiling point dispersion medium component abruptly evaporates and the drying process In the case where the spacer cannot move or is severe, the spacer moves around the substrate together with the droplets due to the sudden boiling of the dispersion medium component having the lowest boiling point, and the spacer placement accuracy may be significantly reduced.

  Further, in the drying method in which the dispersion medium is volatilized while the surface temperature of the substrate is gradually increased after the spacer dispersion liquid droplets have landed on the substrate, the spacer dispersion liquid droplets have landed on the substrate. The surface temperature of the substrate is not particularly limited, but is 20 ° C. or more lower than the boiling point of the lowest boiling point dispersion medium component contained in the dispersion medium of the spacer dispersion liquid, and drying is completed. It is preferable that the surface temperature of the board | substrate until it is 90 degrees C or less, More preferably, it is 70 degrees C or less.

  If the surface temperature of the substrate at the time when the spacer dispersion liquid droplets land on the substrate is lower than the boiling point of the lowest boiling dispersion medium component by less than 20 ° C., the lowest boiling dispersion medium component volatilizes rapidly. If the spacer cannot move or is severe in the drying process, the spacer moves around the substrate together with the droplets due to the sudden boiling of the dispersion medium component having the lowest boiling point, and the spacer placement accuracy may be significantly reduced. is there. Further, when the surface temperature of the substrate until the drying is completed exceeds 90 ° C., the alignment film may be contaminated, and the display quality of the liquid crystal display device may be impaired. Here, the completion of drying means the time when the droplets of the spacer dispersion liquid discharged on the substrate disappear.

  After drying, to increase the adhesion of the spacer to the substrate, to increase the bonding force between the mother particles and the resin particles, or to crosslink the resin particles to increase the solvent resistance (liquid crystal stain resistance) of the resin particles. Furthermore, it is more preferable to heat at a temperature between 100 and 260 ° C.

[Assembly of liquid crystal display device]
A desired liquid crystal display device is obtained by heat-pressing a substrate on which a spacer is selectively arranged by the above-described method and an opposing substrate through a peripheral sealing material and filling a liquid crystal in a gap formed between the substrates. be able to.

(Function)
The spacer dispersion liquid for manufacturing the liquid crystal display device of the present invention uses composite particles in which resin fine particles are present on the surface of the mother particles as spacers dispersed in the dispersion liquid. It is possible to obtain a liquid crystal display device with excellent display quality, which can be firmly fixed after being accurately arranged on a non-display portion (light-shielding region) of the substrate of the liquid crystal display device and there is no light leakage due to spacers.
When composite particles in which resin fine particles are present on the surface of the mother particles are used, they can be firmly fixed to the substrate of the liquid crystal display device because the surface is finer than normal particles without resin fine particles on the surface. This is probably because there are many irregularities and the contact area becomes large.

  Since the present invention has the above-described configuration, the spacer can be accurately arranged on the non-display portion of the liquid crystal display substrate by an ink jet method, and by firmly fixing, there is no light leakage due to the spacer, It became possible to obtain a spacer dispersion liquid for manufacturing a liquid crystal display device capable of obtaining a liquid crystal display device exhibiting excellent display quality.

  Hereinafter, the present invention will be described in more detail with reference to examples. In addition, this invention is not limited to a following example.

[Preparation of resin fine particles]
・ Production of resin fine particles (A) (ionic)
A 500 mL separable flask equipped with a four-neck separable cover, stirring blade, three-way cock, condenser, and temperature probe was charged with 320 mmol of styrene, 3.2 mmol of phenyldimethylsulfonium methylsulfate methacrylate, and 160 g of ion-exchanged water for 45 minutes. After nitrogen substitution, 3.2 mmol of 2,2′-azobis (2-amidinopropane) dihydrochloride was added as an initiator, and polymerization was carried out at 60 ° C. for 6 hours under a nitrogen atmosphere with a stirring speed of 200 rpm. After the reaction, the aggregate was filtered off with a 100 mesh sieve. The synthesized resin fine particles were centrifuged, the supernatant was discarded, and then redispersed with ion-exchanged water. This operation was repeated three times to purify the latex, and then the aqueous dispersion of resin fine particles was lyophilized to obtain resin fine powder having an average particle size of 216 nm and a CV value of 3.3%. This was designated as resin fine particles (A).

・ Production of resin fine particles (B) (ionic)
A 100 mL separable flask equipped with a four-neck separable cover, stirring blade, three-way cock, condenser, temperature probe, 64 mmol of styrene, 15 mmol of butyl acrylate, 0.64 mmol of phenyldimethylsulfonium methyl sulfate, 36 g of ion-exchanged water After replacing with nitrogen for 45 minutes, 0.64 mmol of 2,2′-azobis (2-amidinopropane) dihydrochloride was added as an initiator, and polymerization was performed at a stirring speed of 200 rpm and 60 ° C. for 6 hours in a nitrogen atmosphere. It was. After the reaction, the aggregate was filtered off with a 100 mesh sieve. The synthesized resin fine particles were centrifuged, the supernatant was discarded, and then redispersed with ion-exchanged water. This operation was repeated three times to purify the latex, and then the aqueous dispersion of resin fine particles was lyophilized to obtain resin fine powder having an average particle size of 155 nm and a CV value of 4.5%. This was designated as resin fine particles (B).

・ Production of resin fine particles (C) (ionic)
A 100 mL separable flask equipped with a four-neck separable cover, stirring blade, three-way cock, condenser, temperature probe, 64 mmol of styrene, 32 mmol of butyl acrylate, 0.64 mmol of phenyldimethylsulfonium methyl sulfate, 36 g of ion-exchanged water After replacing with nitrogen for 45 minutes, 0.64 mmol of 2,2′-azobis (2-amidinopropane) dihydrochloride was added as an initiator, and polymerization was performed at a stirring speed of 200 rpm and 60 ° C. for 6 hours in a nitrogen atmosphere. It was. After the reaction, the aggregate was filtered off with a 100 mesh sieve. The synthesized resin fine particles were centrifuged, the supernatant was discarded, and then redispersed with ion-exchanged water. This operation was repeated three times to purify the latex, and the aqueous dispersion of resin fine particles was lyophilized to obtain resin fine particle powder having an average particle size of 242 nm and a CV value of 5.6%. This was designated as resin fine particles (C).

-Preparation of resin fine particles (D) (hydrophilic)
A 100 mL separable flask equipped with a 4-neck separable cover, stirring blade, three-way cock, condenser, and temperature probe was charged with 64 mmol of styrene, 32 mmol of butyl acrylate, 14 mmol of tetraethylene glycol acrylate, and 36 g of ion-exchanged water, and purged with nitrogen for 45 minutes. Then, 2,4′-azobis (2-amidinopropane) dihydrochloride (0.64 mmol) was added as an initiator, and polymerization was performed at a stirring speed of 200 rpm and 60 ° C. for 6 hours in a nitrogen atmosphere. After the reaction, the aggregate was filtered off with a 100 mesh sieve. The synthesized resin fine particles were centrifuged, the supernatant was discarded, and then redispersed with ion-exchanged water. This operation was repeated three times to purify the latex, and then the aqueous dispersion of resin fine particles was lyophilized to obtain resin fine particle powder having an average particle size of 322 nm and a CV value of 5.0%. This was designated as resin fine particles (D).

・ Production of resin fine particles (E) (reactive functional groups)
A 100 mL separable flask equipped with a four-neck separable cover, stirring blade, three-way cock, condenser, and temperature probe was charged with 64 mmol of styrene, 32 mmol of butyl acrylate, 4 mmol of glycidyl methacrylate, and 36 g of ion-exchanged water, and purged with nitrogen for 45 minutes. Thereafter, 0.64 mmol of 2,2′-azobis (2-amidinopropane) dihydrochloride as an initiator was added, and polymerization was performed at a stirring speed of 200 rpm and 60 ° C. for 6 hours in a nitrogen atmosphere while maintaining the pH at 8-9. went. After the reaction, the aggregate was filtered off with a 100 mesh sieve. The synthesized resin fine particles were centrifuged, the supernatant was discarded, and then redispersed with ion-exchanged water. This operation was repeated three times to purify the latex, and then the aqueous dispersion of resin fine particles was freeze-dried to obtain a resin fine particle powder having an average particle size of 185 nm and a CV value of 4.8%. This was designated as resin fine particles (E).

・ Production of resin fine particles (F) (crosslinking)
A 100 mL separable flask equipped with a four-neck separable cover, stirring blade, three-way cock, condenser, and temperature probe was charged with 64 mmol of styrene, 32 mmol of butyl acrylate, 0.01 mmol of 1,6-hexanediol diacrylate, and 36 g of ion-exchanged water. Then, after nitrogen substitution for 45 minutes, 0.64 mmol of 2,2′-azobis (2-amidinopropane) dihydrochloride was added as an initiator, and polymerization was performed at a stirring speed of 200 rpm and 60 ° C. for 6 hours in a nitrogen atmosphere. . After the reaction, the aggregate was filtered off with a 100 mesh sieve. The synthesized resin fine particles were centrifuged, the supernatant was discarded, and then redispersed with ion-exchanged water. This operation was repeated three times to purify the latex, and then the aqueous dispersion of resin fine particles was lyophilized to obtain resin fine powder having an average particle size of 355 nm and a CV value of 5.5%. This was designated as resin fine particles (F).

・ Production of resin fine particles (G) (post-crosslinking)
A 100 mL separable flask equipped with a four-neck separable cover, stirring blade, three-way cock, condenser, and temperature probe was charged with 64 mmol of styrene, 16 mmol of butyl acrylate, 20 mmol of N-butoxymethylacrylamide, and 36 g of ion-exchanged water, and nitrogen was added for 45 minutes. After the substitution, 0.64 mmol of 2,2′-azobis (2-amidinopropane) dihydrochloride was added as an initiator, and polymerization was performed at a stirring speed of 200 rpm and 60 ° C. for 6 hours in a nitrogen atmosphere. After the reaction, the aggregate was filtered off with a 100 mesh sieve. The synthesized resin fine particles were centrifuged, the supernatant was discarded, and then redispersed with ion-exchanged water. This operation was repeated three times to purify the latex, and the aqueous dispersion of resin fine particles was lyophilized to obtain a resin fine particle powder having an average particle size of 258 nm and a CV value of 5.1%. This was designated as resin fine particles (G).

-Production of resin fine particles (H) 100 mL separable flask equipped with a four-neck separable cover, stirring blade, three-way cock, condenser, temperature probe, hydroxyethyl methacrylate 40 mmol, isobutyl methacrylate 30 mmol, methacrylic acid 5 mmol, ion 36 g of exchange water was added and the atmosphere was purged with nitrogen for 45 minutes. Then, 0.64 mmol of 2,2′-azobis (2-amidinopropane) dihydrochloride was added as an initiator, and the stirring rate was 200 rpm at 60 ° C. for 6 hours in a nitrogen atmosphere. Polymerization was performed. After the reaction, the aggregate was filtered off with a 100 mesh sieve. The synthesized resin fine particles were centrifuged, the supernatant was discarded, and then redispersed with ion-exchanged water. This operation was repeated three times to purify the latex, and then the aqueous dispersion of resin fine particles was lyophilized to obtain resin fine powder having an average particle size of 322 nm and a CV value of 4.3%. This was designated as resin fine particles (H).

[Preparation of mother particles]
-Preparation of mother particles (M1) (having an ionic group on the surface)
A separable flask was charged with 15 parts by weight of divinylbenzene, 4.5 parts by weight of isooctyl acrylate, 0.5 parts by weight of methacrylic acid, and 1.3 parts by weight of benzoyl peroxide as a polymerization initiator, and stirred and mixed uniformly. Next, 20 parts by weight of a 3% by weight aqueous solution of polyvinyl alcohol (trade name “Kuraray Poval GL-03”, manufactured by Kuraray Co., Ltd.) and 0.5 parts by weight of sodium dodecyl sulfate were added, and the mixture was uniformly stirred and mixed. 140 parts by weight of water was added. Next, under a nitrogen stream, the mixed solution was stirred for 15 hours at 80 ° C. to obtain particles. The obtained particles were sufficiently washed with hot water and acetone, and thereafter classified, and acetone was volatilized to obtain particles having an average particle diameter of 4.5 μm and a CV value of 3.0%. This was designated as mother particles (M1).

-Preparation of mother particle (M2) Commercially available crosslinked resin particles having a particle diameter of 4.5 µm (trade name "Micropearl SP", manufactured by Sekisui Chemical Co., Ltd.) were prepared as mother particles (M2).

[Production of composite particles]
Preparation of composite particles (CA1) using resin fine particles (A) 0.015 g of resin fine particles (A) are dispersed in 5 mL of distilled water, 0.1 g of mother particles (M2) are added, and the mixture is stirred at a stirring speed of 40 rpm for 24 hours. did. The obtained composite particles were centrifuged at 3000 rpm for 5 minutes, and the supernatant was discarded and redispersed with ion-exchanged water. This centrifugation operation was repeated three times to purify the composite particles. This was designated as composite particles (CA1).
The coverage of the obtained composite particles (CA1) was 32%.

The coverage of the composite particles, that is, the coverage of the base particles with the resin fine particles was calculated by the following equation by obtaining the number of coatings by observation with an electron microscope.
Covering rate (%) = {number of coatings / maximum number of coatings (theoretical value)} × 100

Preparation of composite particles (CA2) using resin fine particles (A) in an aqueous electrolyte solution 0.015 g of resin fine particles (A) are dispersed in 5 mL of an aqueous electrolyte solution in which 100 mmol of sodium chloride is dissolved as an electrolyte, and mother particles (M2 ) 0.1 g was added, and composite particles were obtained by the same operation as composite particles (CA1). This was designated as composite particles (CA2).
The coverage of the obtained composite particles (CA2) was 64%.

-Preparation of composite particles (CB1) using resin fine particles (B) 0.015 g of resin fine particles (B) are dispersed in 5 mL of distilled water, 0.1 g of mother particles (M2) are added, and the same as composite particles (CA1) Composite particles were obtained by the operation of This was designated as composite particles (CB1).
The coverage of the obtained composite particles (CB1) was 28%.

Preparation of composite particles (CB2) using resin fine particles (B) in an aqueous electrolyte solution 0.015 g of resin fine particles (B) are dispersed in 5 mL of an aqueous electrolyte solution in which 300 mmol of sodium chloride is dissolved as an electrolyte, and mother particles (M2 ) 0.1 g was added, and composite particles were obtained by the same operation as composite particles (CA1). This was designated as composite particles (CB2).
The coverage of the obtained composite particles (CB2) was 55%.

Preparation of composite particles (CB3) using resin fine particles (B) in aqueous electrolyte solution 0.015 g of resin fine particles (B) are dispersed in 5 mL of an aqueous electrolyte solution in which 300 mmol of sodium chloride is dissolved as an electrolyte, and mother particles (M1 ) 0.1 g was added, and composite particles were obtained by the same operation as composite particles (CA1). This was designated as composite particles (CB3).
The coverage of the obtained composite particles (CB3) was 75%.

-Preparation of composite particles (CC1) using resin fine particles (C) 0.015 g of resin fine particles (C) are dispersed in 5 mL of distilled water, 0.1 g of mother particles (M2) are added, and the same as composite particles (CA1) Composite particles were obtained by the operation of This was designated as composite particles (CC1).
The coverage of the obtained composite particles (CC1) was 21%.

Preparation of composite particles (CC2) using resin fine particles (C) in an aqueous electrolyte solution 0.015 g of resin fine particles (C) are dispersed in 5 mL of an aqueous electrolyte solution in which 300 mmol of sodium chloride is dissolved as an electrolyte, and mother particles (M2 ) 0.1 g was added, and composite particles were obtained by the same operation as composite particles (CA1). This was designated as composite particles (CC2).
The coverage of the obtained composite particles (CC2) was 52%.

-Preparation of composite particles (CC3) using resin fine particles (C) in alcohol mixed solvent 0.015 g of resin fine particles (C) were dispersed in 10 mL of a 1: 1 (weight ratio) water / methanol mixed solvent, 0.1 g of particles (M2) was added, and composite particles were obtained in the same manner as composite particles (CA1). This was designated as composite particles (CC3).
The coverage of the obtained composite particles (CC3) was 74%.

Preparation of composite particles (CD1) using resin fine particles (D) in an aqueous electrolyte solution 0.015 g of resin fine particles (D) are dispersed in 5 mL of an aqueous electrolyte solution in which 300 mmol of sodium chloride is dissolved as an electrolyte, and mother particles (M2 ) 0.1 g was added, and composite particles were obtained by the same operation as composite particles (CA1). This was designated as composite particles (CD1).
The coverage of the obtained composite particles (CD1) was 55%.

-Preparation of composite particles (CE1) using resin fine particles (E) in an aqueous electrolyte solution 0.015 g of resin fine particles (E) was dissolved in 300 mmol of sodium chloride as an electrolyte, and the pH was adjusted by adding a small amount of acetic acid. Disperse in 5 mL of an aqueous electrolyte solution adjusted to 3 to 4, add 0.1 g of mother particles (M2), and stir at a stirring speed of 40 rpm for 24 hours while keeping the temperature at 40 ° C. ) And allowed to react. The obtained composite particles were centrifuged at 3000 rpm for 5 minutes, and the supernatant was discarded and redispersed with ion-exchanged water. This centrifugation operation was repeated three times to purify the composite particles. This was designated as composite particles (CE1).
The coverage of the obtained composite particles (CE1) was 58%.

Preparation of composite particles (CF1) using resin fine particles (F) in an electrolyte aqueous solution 0.015 g of resin fine particles (F) are dispersed in 5 mL of an aqueous electrolyte solution in which 300 mmol of sodium chloride is dissolved as an electrolyte, and mother particles (M2 ) 0.1 g was added, and composite particles were obtained by the same operation as composite particles (CA1). This was designated as composite particles (CF1).
The coverage of the obtained composite particles (CF1) was 51%.

Preparation of composite particles (CG1) using resin fine particles (G) in an aqueous electrolyte solution 0.015 g of resin fine particles (G) are dispersed in 5 mL of an aqueous electrolyte solution in which 300 mmol of sodium chloride is dissolved as an electrolyte, and mother particles (M2 ) 0.1 g was added, and composite particles were obtained by the same operation as composite particles (CA1). This was designated as composite particles (CG1).
The coverage of the obtained composite particles (CG1) was 62%.

-Production of composite particles (CH1) by impact method in high-speed air current After mixing using 1.0 g of resin fine particles (H) and 3.0 g of mother particles (M2), Example 1 of JP 2000-347191 A Using a hybridization system (model “NHS-0”, manufactured by Nara Machinery Co., Ltd.) as disclosed, resin fine particles were adhered to the surface of the mother particles by a high-speed air current impact method to obtain composite particles. . This was designated as composite particles (CH1).
The coverage of the obtained composite particles (CH1) was 42%.

(Example 1)
[Preparation of spacer dispersion]
Slowly add 0.15 g of the spacer (composite particle (CA1)) obtained above to a solvent having a composition consisting of 15.0 g of isopropyl alcohol, 40.0 g of ethylene glycol, and 45.0 g of water, and thoroughly stir and mix with a sonicator. Then, the mixture was uniformly dispersed, and then filtered through a stainless mesh having an aperture of 10 μm to prepare a spacer dispersion.

[Evaluation of dispersibility]
Regarding the dispersibility of the spacer in the solvent, the spacer dispersion was filtered through a stainless steel mesh having an opening of 10 μm when the spacer dispersion was adjusted, and evaluated according to the following criteria.
[Criteria]
A: The stainless steel mesh was hardly clogged, and the dispersion could be filtered smoothly.
○ The dispersion passed through the stainless mesh, but some clogging was observed in the mesh after filtration. Also, the spacer that settled over time could be easily redispersed by shaking the container.
Δ: The stainless mesh was clogged and could not be filtered smoothly, but could be filtered over time. However, the spacer that settled with time did not re-disperse even when the container was shaken.
X: The stainless mesh was clogged and could not be filtered.
The results are shown in Table 1.

[Preparation of substrate]
As a substrate for a liquid crystal display cell, a TFT array model substrate imitating a step existing in a color filter substrate and a TFT array substrate was prepared. The color filter substrate is provided with a black matrix (width: 25 μm, length: 150 μm interval, width: 75 μm interval, thickness: 0.2 μm) on a glass substrate by a conventionally known method, red, green A color filter pixel (thickness: 1.5 μm) composed of three colors of blue was formed therebetween. Furthermore, an overcoat layer and an ITO transparent electrode were provided thereon, and a polyimide resin solution (trade name “Sunever SE1211”, manufactured by Nissan Chemical Industries, Ltd.) was uniformly applied thereon by spin coating, and dried at 150 ° C. Later, it was baked and cured at 230 ° C. for 1 hour to form an alignment film.
In the TFT array model substrate, a step portion (width: 8 μm, thickness: 0.2 μm) made of copper foil was provided on a glass substrate at a position opposite to the black matrix of the color filter substrate. And the ITO transparent electrode was provided on copper foil, and the alignment film was further formed by the said method.

[Spacer placement by inkjet device]
A TFT array model substrate having the above steps is mounted on a stage heated to 45 ° C. by an attached heater, and an ink jet apparatus in which a nozzle having a diameter of 50 μm is mounted at the tip of a piezo head, Aiming at a step corresponding to the black matrix, droplets of the spacer dispersion liquid were ejected at intervals of 110 μm on every other vertical line, and spacers were arranged at a pitch of 110 μm × 150 μm. . The distance between the nozzle (head surface) and the substrate during ejection was 0.5 mm, and a double pulse method was used. The dispersion density of the spacers thus arranged was 180 pieces / mm ² . After confirming that the spacer dispersion liquid discharged onto the substrate on the stage was completely dried visually, a hot plate heated to 150 ° C. to remove the remaining dispersion medium and fix the spacer to the substrate Moved up and heated and left for 15 minutes.

[Production of liquid crystal display cell]
The TFT array model substrate in which the spacers are arranged as described above and the peripheral portion of the color filter substrate which is the counter substrate are bonded together via a sealing material, and the sealing material is cured by heating at 150 ° C. for 1 hour, After producing an empty cell in which the cell gap becomes the particle diameter of the spacer, this empty cell is filled with liquid crystal (trade name “ZLI-4720-000”, manufactured by Merck & Co., Inc.) by a vacuum method and filled with a sealing agent. Was sealed to prepare a liquid crystal display cell.

[Performance evaluation]
The performance (1. stickiness, 2. liquid crystal purity, 3. display image quality) of the liquid crystal display cell obtained above was evaluated by the following method. The results are shown in Table 1.

1. Adhesiveness Adhesiveness was measured by measuring the number of particles in a range of 1.0 mm ² before and after applying air with an air gun to a substrate on which the spacers were dispersed and heat-treated before bonding. The ratio of the number of particles was calculated and obtained as a percentage. In this case, as the air blowing conditions, an air blowing pressure of 4.0 kg / cm ² , a nozzle diameter of 2 mm, a vertical distance of 5 mm, and a time of 15 seconds were used.

2. Liquid crystal purity The liquid crystal purity (liquid crystal stain resistance) is determined by dispersing 0.1 g of the spacer in 2 mL of the liquid crystal and leaving it at 85 ° C. for 300 hours, collecting the liquid crystal, and measuring the purity of the liquid crystal by gas chromatography. I asked for it.

3. Display image quality A predetermined voltage was applied to the liquid crystal display cell, and the presence or absence of display defects such as light leakage caused by the spacer was observed with an electron microscope, and the display image quality was evaluated according to the following criteria.
[Criteria]
○: There was almost no spacer in the display area, and there was no light leakage due to the spacer, and the image quality was good.
Δ: Some spacers were observed in the display area, and light leakage due to the spacers was observed.
×: Many spacers were observed in the display area, and light leakage due to the spacers occurred.

(Examples 2 to 13) and (Comparative Example 1)
Except for changing the spacer type (composite particle type) as shown in Table 1, in the same manner as in Example 1, the preparation of the spacer dispersion, the evaluation of the dispersibility, the preparation of the substrate, the arrangement of the spacer by the ink jet device, the liquid crystal display Cell fabrication and performance evaluation were performed. The results are shown in Table 1.

From Table 1, Examples 1 to 9, and 12 in which the resin fine particles are hydrophilic by including an ionic group are particularly excellent in dispersibility. In addition, Examples 10 to 12 in which the resin fine particles are cross-linked or bonded to the mother particles by a reactive functional group were particularly excellent in liquid crystal purity (liquid crystal stain resistance).
As a result, in the embodiment, the spacers are arranged almost accurately in the non-display area, and the sticking property is good so that the spacers do not move and the display image quality is excellent. However, in Comparative Example 1, the arrangement accuracy of the spacers was poor and the spacers were arranged up to the display area, and the display image quality was inferior. This is presumably because the spacers moved during liquid crystal injection because of poor adhesion.

It is sectional drawing which shows an example of a liquid crystal display device.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Transparent substrate 2 Polarizing plate 3 Transparent electrode 4 Color filter 5 Black matrix 6 Liquid crystal 7 Spacer 8 Alignment film 9 Sealing material

Claims (6)

A spacer dispersion liquid for manufacturing a liquid crystal display device in which spacers are arranged at arbitrary positions on a substrate by an inkjet method, and the spacers dispersed in the spacer dispersion liquid have resin fine particles on the surface of the mother particles A spacer dispersion liquid for manufacturing a liquid crystal display device, wherein the dispersion liquid is a composite particle. The spacer dispersion liquid for manufacturing a liquid crystal display device according to claim 1, wherein the resin fine particles are a hydrophilic resin. 2. The spacer dispersion for manufacturing a liquid crystal display device according to claim 1, wherein the composite particles are composite particles obtained by adhering resin fine particles having an ionic group to the surface of the base particles in a liquid phase. liquid. 4. The spacer dispersion liquid for producing a liquid crystal display device according to claim 3, wherein the surface of the mother particle has an ionic group. The resin fine particles having an ionic group have a functional group (a) that reacts with the mother particle, and the mother particle also has a functional group (b) that reacts with the functional group (a). The spacer dispersion liquid for manufacturing the liquid crystal display device according to claim 3 or 4. 6. The spacer dispersion liquid for producing a liquid crystal display device according to claim 3, wherein the resin fine particles having an ionic group are resin fine particles which are crosslinked or can be crosslinked later.

Images