JP2008015346A - Spacer particle dispersion liquid, method for manufacturing liquid crystal display device, and liquid crystal display device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a spacer particle dispersion liquid with which the spacer particles can be rapidly and accurately and selectively arranged in specific positions corresponding to the non-pixel region on a substrate by using an ink jet device, a method for manufacturing a liquid crystal display device, and a liquid crystal display device. <P>SOLUTION: The spacer particle dispersion liquid contains the spacer particles 1 and a solvent 5 and is used for arranging the spacer particles on the surface of a substrate using the ink jet device. In a step of drying the droplets discharged and formed on the surface of the substrate, the spacers aggregate each other within the droplets before the droplets completely dry up, and the boiling point of the solvent is 50 to 190°C. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention relates to a spacer particle dispersion liquid crystal device capable of quickly and selectively disposing spacer particles at a specific position corresponding to a non-pixel region on a substrate using an ink jet device, and a liquid crystal display device And a liquid crystal display device.

Currently, liquid crystal display devices are widely used in personal computers, portable electronic devices, and the like. As shown in FIG. 9, a general liquid crystal display device has a structure in which two transparent substrates 201 and 202 are stacked so as to face each other.

On the inner surface of the transparent substrate 201, a color filter 203 and a black matrix 204 that defines the color filter 203 are formed. An overcoat layer 205 is formed on the color filter 203 and the black matrix 204. A transparent electrode 206 is formed on the overcoat layer 205. Further, an alignment film 207 is formed so as to cover the transparent electrode 206. On the other hand, a transparent electrode 208 is formed on the inner surface of the transparent substrate 202 at a position facing the color filter 203. Further, an alignment film 209 is formed so as to cover the inner surface of the transparent substrate 202 and the transparent electrode 208. On the other hand, polarizing plates 210 and 211 are disposed on the outer surfaces of the transparent substrates 201 and 202, respectively. The transparent electrodes 206 and 208 include a pixel electrode disposed in the pixel region and an electrode disposed outside the pixel region.

The transparent substrate 201 and the transparent substrate 202 are bonded via a sealant 212 in the vicinity of the outer peripheral edge of each. Spacer particles 213 are arranged in the gap between the alignment film 207 and the alignment film 209, and liquid crystal 214 is sealed. In the liquid crystal display device having such a structure, the spacer particles 213 function to regulate the distance between the two transparent substrates 201 and 202 and maintain an appropriate thickness (cell gap) of the liquid crystal layer.

In the conventional method for manufacturing a liquid crystal display device, the spacers are uniformly and randomly distributed on the transparent substrate, and as shown in FIG. 9, on the pixel electrode, that is, the display portion (pixel region) of the liquid crystal display device. ) Was also easy to place a spacer. The spacer is generally made of synthetic resin, glass, or the like, and when the spacer is disposed on the pixel electrode, the spacer portion leaks light due to the biasing action. Further, if the alignment of the liquid crystal on the spacer surface is disturbed, light leakage occurs, the contrast and color tone are lowered, and the display quality is deteriorated. On the other hand, in a TFT liquid crystal display device, TFT elements are arranged on a substrate. When the spacer is disposed on the TFT element, the TFT element may be damaged when pressure is applied to the substrate.

In order to solve such problems associated with random dispersion of spacers, various attempts have been made to dispose the spacers under a light-shielding layer (a portion defining a pixel region, hereinafter also referred to as a non-pixel region).

As a method of arranging the spacers only at specific positions, for example, Patent Document 1 discloses a method of dispersing the spacers through the mask after matching the position where the mask having the opening is desired to be arranged. Patent Document 2 discloses a method of electrostatically attracting a spacer to a photosensitive member and then transferring the spacer to a transparent substrate. Further, Patent Document 3 discloses a method for manufacturing a liquid crystal display device in which a spacer is arranged at a specific position by electrostatic repulsion by applying a voltage to pixel electrodes on a substrate and dispersing charged spacers. Has been.

However, in the method described in Patent Document 1 or Patent Document 2, since the mask and the photoconductor are in direct contact with the substrate, the alignment film on the substrate is damaged, and the liquid crystal display image quality of the manufactured liquid crystal display device is low. There was a problem of lowering. Further, in the method described in Patent Document 3, an electrode according to the pattern to be arranged is required, so that it is impossible to arrange the spacer at an arbitrary position.

For example, Patent Document 4 discloses a method of arranging spacers using an ink jet apparatus to deal with such a problem. In this method, the mask and the photoconductor do not come into direct contact with the substrate itself, and the spacer can be arranged in an arbitrary pattern at an arbitrary position.

However, since the spacer particle dispersion to be discharged contains spacer particles having a particle size of about 1 to 10 μm, the nozzle diameter of the inkjet head must be increased in order to discharge linearly. It was. As a result, even if the droplets ejected onto the substrate become large and ejected aiming at a light-shielding region that is not a pixel region, the droplets protrude from the non-pixel region to the pixel region, and the spacer is disposed in the pixel region. There was a thing.

When the liquid droplets that protrude into the pixel area are dried and reduced around the center of landing, the spacer particles 41 in the liquid droplets 40 are moved by a force that reduces the outer periphery of the liquid droplets 40 as shown in FIG. However, as shown in FIG. 10B, the droplet 40 ′ is dried with the landing diameter, and the droplet 40 ′ is not reduced toward the landing center. In many cases, the spacer particles 41 ′ are not aggregated in the non-pixel region. For this reason, the droplets of the spacer particle dispersion discharged by the ink jet apparatus have to be devised so that the spacer particles are reduced to the center of landing and the spacer particles are collected in the non-pixel region. Without such a device, the spacers are arranged in the pixel region, and the contrast and color tone may be lowered, and the display quality may be deteriorated. FIGS. 10A and 10B are explanatory views schematically showing a state of drying the droplets of the spacer particle dispersion liquid landed on the conventional substrate surface.

For example, in Patent Documents 5 and 6, etc., the medium in which the spacer is dispersed is combined with a solvent having an appropriate boiling point and surface tension, and the receding contact angle resulting from the interaction between the substrate and these solvents is appropriately set. As shown in FIG. 10 (a), a method is disclosed in which spacer particles are aggregated and arranged in a specific region by shrinking the droplet diameter at the time of drying, as shown in FIG.
However, even with these methods, depending on the type of substrate, particularly an alignment film (particularly an alignment film having a high surface tension and a receding contact angle of 5 degrees or less), the liquid of the spacer particle dispersion liquid may be used. There was a problem that the droplet diameter was not reduced even during the drying process of the droplets, and the spacer particles did not collect as shown in FIG.
Furthermore, in general, when trying to increase the receding contact angle of the droplets of the spacer particle dispersion liquid, a solvent having a high surface tension is apt to be used, and such a high surface tension solvent has a high boiling point and is thus dried. There was a problem that it was difficult to do.
Japanese Patent Laid-Open No. 4-198919 JP-A-6-258647 JP-A-10-339878 JP-A-57-58124 JP 2003-279999 A JP 2005-189651 A

An object of the present invention is to arrange spacer particles quickly and accurately at a specific position corresponding to a non-pixel region on a substrate using an ink jet apparatus in view of the above-described state of the prior art. The object is to provide a spacer particle dispersion, a method for manufacturing a liquid crystal display device, and a liquid crystal display device.

The present invention relates to a spacer particle dispersion liquid that contains spacer particles and a solvent and is used when the spacer particles are arranged on the surface of the substrate using an ink jet apparatus, and is a liquid that is formed by discharging onto the surface of the substrate. In the step of drying the droplets, the spacer particles are dispersed in the droplets before the droplets are completely dried, and the solvent has a boiling point of 50 to 190 ° C.

The present invention is also a method for manufacturing a liquid crystal display device having a pixel region and a non-pixel region, and the spacer particle dispersion is discharged onto the surface of the first substrate or the second substrate using an ink jet device. Thereby, a step 1 of arranging droplets of the spacer particle dispersion at a specific position corresponding to the non-pixel region, a step 2 of aggregating spacer particles in the droplets of the spacer particle dispersion, and the first This is a method of manufacturing a liquid crystal display device, comprising the step 3 of superposing the second substrate and the second substrate so as to face each other through the liquid crystal and the agglomerated spacer particles.

Moreover, this invention is a liquid crystal display device which uses the manufacturing method of the spacer particle dispersion liquid of this invention or the liquid crystal display device of this invention.
Hereinafter, the present invention will be described in detail.

As a result of intensive studies, the present inventors have found that a spacer particle dispersion used when arranging spacer particles on the surface of a substrate using an inkjet device contains a solvent having a boiling point within a predetermined range, and If the state of the droplets discharged and formed on the surface of the substrate changes during the drying process, that is, if the dispersibility of the spacer particles in the solvent changes during the drying process, the spacer particles can be quickly and purposefully As a result, the present invention has been completed.

The spacer particle dispersion of the present invention contains spacer particles and a solvent, and is used when the spacer particles are arranged on the surface of a substrate using an ink jet apparatus.
In the step of drying the droplets discharged onto the surface of the substrate, the spacer particle dispersion of the present invention aggregates the spacer particles inside the droplets before the droplets are completely dried. That is, the spacer particle dispersion of the present invention causes the spacer particles to aggregate inside the droplet. When the droplet formed by discharging onto the substrate surface is dried, the conventional spacer described with reference to FIG. Unlike the particle dispersion, the spacer particles aggregate in the droplets regardless of the force with which the outer periphery of the droplets shrinks. In some cases, the outer periphery of the droplet contracts following aggregation of the spacer particles.

FIG. 1 is a cross-sectional view showing a drying process of droplets made of the spacer particle dispersion of the present invention discharged onto the substrate surface. FIG. 1 (a) shows the droplet diameter formed on the substrate surface when the droplets are dried. (B) shows the case where the landing diameter of the droplet formed on the substrate surface does not change as the droplet dries. In FIGS. 1A and 1B, the broken lines indicate the landing diameters of the droplets, and the “landing diameter” means that the spacer particle dispersion of the present invention is discharged onto the substrate surface using an ink jet apparatus. It means the diameter of a circle drawn on the outer periphery when the formed droplet is viewed from above. Further, in FIG. 1A, an arrow indicates a direction in which the droplet 5 is reduced.

As shown in FIG. 1A, when the landing diameter of the droplet made of the spacer particle dispersion of the present invention is reduced as it is dried, the spacer particles 1 in the droplet 5 immediately after landing are in the droplet 5. However, when the droplet 5 is dried, the droplet 5 is reduced. On the other hand, the spacer particle 1 in the droplet 5 does not depend on the force that the outer peripheral portion of the droplet 5 is reduced. It will be in the aggregated state in the vicinity. Thereafter, the droplets 5 continue to shrink as the drying progresses, and after the drying is completed, only the spacer particles 1 are arranged in an aggregated state on the substrate surface.
On the other hand, as shown in FIG. 1B, when the landing diameter of the droplet made of the spacer particle dispersion of the present invention does not change with drying, the spacer particles 1 ′ in the droplet 5 ′ immediately after landing are: Although not aggregated in the droplet 5 ', when the droplet 5' is dried, the landing diameter of the droplet 5 'does not change and its height decreases, while the spacer particles 1 in the droplet 5' are reduced. “Is agglomerated in the vicinity of the center of impact, regardless of the force by which the outer periphery of the droplet 5 ′ shrinks. Thereafter, the droplet 5 ′ continues to decrease in height as the drying progresses, and after the drying is completed, only the spacer particles 1 ′ are aggregated on the substrate surface.
In the spacer particle dispersion of the present invention, the spacer particles in the droplet before drying may be dispersed in the droplet as shown in FIG. It may be in a state where it spreads and settles down on the bottom part of.

As shown in FIGS. 1 (a) and 1 (b), the spacer particle dispersion of the present invention reduces the weight of the droplets formed on the substrate surface by 5% by weight or more (hereinafter, this state is referred to as a late drying stage). It is also preferable that the spacer particles in the droplets aggregate. That is, the spacer particle dispersion of the present invention is preferably such that the composition of the droplet changes when the droplet formed on the substrate surface is dried and its weight is reduced by 5% by weight or more.
When the spacer particles are aggregated when the weight of the droplets is reduced by less than 5% by weight, the spacer particle dispersion of the present invention is inferior in handleability and before being discharged onto the substrate surface using an ink jet device. In some cases, the spacer particles agglomerate, and the clogging of the nozzles and the arrangement accuracy of the droplets may decrease.

In the spacer particle dispersion of the present invention, among the solvents used in the spacer particle dispersion of the present invention, the solvent remaining in the late drying stage of the droplets formed on the surface of the substrate is poor in spacer particle dispersibility. By doing so, aggregation of the spacer particles can be realized in the late drying stage of the droplets. On the other hand, for example, among the solvents used in the spacer particle dispersion liquid, when the dispersibility of the spacer particles does not change relative to the solvent remaining in the late drying stage of the droplets, or when the dispersibility is improved, As the drying of the droplet proceeds, the spacer particle dispersion does not aggregate. In particular, when the receding contact angle of the spacer particle dispersion of the present invention is low (that is, when the droplet does not shrink with drying, see FIG. 10B), the spacer particles move with the progress of drying of the droplet. Since the droplets do not aggregate due to the reduction of the droplets, the spacer particles cannot be arranged in an aggregated state at the target position on the substrate surface.

In the spacer particle dispersion of the present invention in which the composition of the droplets changes as the drying of the droplets progresses, the solvent is a mixed solvent in which a plurality of solvents having different drying conditions such as boiling point are mixed, A mixed solvent having such a composition as to be excellent in the dispersibility of the spacer particles immediately after the formation of the droplets, while decreasing the dispersibility of the spacer particles in the later drying stage of the droplets is preferably used.

As a plurality of solvents having different drying conditions constituting the mixed solvent, for example, when a solvent having a different boiling point is selected, the difference in boiling point is 10 ° C. or more while considering dispersibility with respect to the spacer particles to be used. It is preferable to select one. When the temperature is lower than 10 ° C., the solvent composition of the spacer particle dispersion is less likely to change until the droplet is completely dried after the droplet made of the spacer particle dispersion of the present invention is formed on the surface of the substrate. Since the dispersibility of the particles does not change, the effect of the present invention that the spacer particles aggregate may not be obtained.
However, in the spacer particle dispersion of the present invention, the solvent has a lower limit of boiling point of 50 ° C. and an upper limit of 190 ° C. When the temperature is lower than 50 ° C., the solvent is likely to be volatilized too easily, and when the spacer particle dispersion of the present invention is discharged using an ink jet apparatus, the solvent volatilizes in the vicinity of the nozzle and the spacer particles agglomerate. When the temperature exceeds ℃, the droplets of the spacer particle dispersion of the present invention formed on the substrate surface are difficult to dry, and it takes a long time to arrange the spacer particles using the spacer particle dispersion of the present invention. Therefore, when solvents having different boiling points are mixed as the mixed solvent, a solvent having a lower limit of boiling point within the range of 50 ° C. and an upper limit within 190 ° C. is appropriately selected.
The minimum with the preferable boiling point of the said solvent is 70 degreeC, and a preferable upper limit is 150 degreeC. In the present specification, the boiling point of the solvent is a value under 1 atm.

Examples of the solvent having such a boiling point include water, methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, 2-methyl-1-propanol (isobutyl alcohol), 2- Methyl-2-propanol (tert-butyl alcohol), 1-pentanol, 2-pentanol, 3-pentanol, 2-methyl-1-butanol, 3-methyl-1-butanol (isopentyl alcohol), 2- Methyl-2-butanol (tert-pentyl alcohol), 3-methyl-2-butanol, 2,2-dimethyl-1-propanol (neopentyl alcohol), 1-hexanol, 1-methoxy-2-propanol, 2-methyl -1-pentanol, 4-methyl-2-pentanol (methyl isobutyl) Lucalbinol), 2-ethyl-1-butanol, furfuryl alcohol, tetrahydrofurfuryl alcohol, 1,2-propanediol (propylene glycol), ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monoisopropyl ether, ethylene glycol Monobutyl ether, ethylene glycol mono t-butyl ether, ethylene glycol dimethyl ether, ethylene glycol diethyl ether, ethylene glycol diacetate (ethylene acetate), ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monoformate ester, 1, 2-propanediol (propylene glycol), propylene Glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, propylene glycol monomethyl ether acetate, propylene glycol monoethyl ether acetate, propylene glycol monomethyl ether propionate, propylene glycol diacetate, 3-methoxy Butanol (1,3-butanediol monomethyl ether), 3-methoxy-3-methyl-1-butanol, diethylene glycol dimethyl ether, diethylene glycol diethyl ether, diethylene glycol methyl ethyl ether, diethylene glycol methyl isopropyl ether, dipropylene glycol monomethyl ether, dipropyl Lenglycol dimethyl ether, glycerin monoacetate (monoacetin), dioxane, trioxane, THF, acetone, MEK, ethyl acetate, n-propyl acetate, isopropyl acetate, butyl acetate, ethyl butyrate, methyl lactate, ethyl lactate, butyl lactate, malonic acid Dimethyl, ethyl-3-ethoxypropionate, 3-methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate, methyl acetoacetate, ethyl acetoacetate, phenol, hexane, heptane, octane, nonane, decane, toluene, ethylbenzene , DMF, DMSO, diisopropyl ether, dipropyl ether, N, N-dimethylformamide, N, N-diethylformamide, N, N-diethylethanolamine, diacetone alcohol and the like. That.

Further, the mixed solvent is appropriately determined from the above-mentioned solvents in consideration of the relationship with the spacer particles used in the spacer particle dispersion of the present invention. For example, (1) Late drying stage of the droplets The difference (A) between the solubility parameter (SP value) and the SP value on the surface of the spacer particles in the period up to (hereinafter also referred to as the first drying period) satisfies the following formula (1), and the solvent in the latter drying stage of the droplets The difference (B) between the solubility parameter (SP value) of the mixture and the solubility parameter (SP value) of the spacer particle surface satisfies the following formula (2), and (2) the spacer particles in the first drying stage of the droplets A mixed solvent in which the difference (θs2−θs1) between the contact angle (θs1) and the contact angle (θs2) with the spacer particles in the latter stage of drying of the droplet is 1 degree or more; (3) in the first drying stage of the droplet Spacer grain The zeta potential of a mixed solvent or the like to be higher than the zeta potential of the spacer particles in the dry later of the droplet and the like.
| A | ≦ 5 (1)
| B | ≧ | A | +0.2 (2)

The mixed solvent satisfying the above formulas (1) and (2) is appropriately determined depending on the SP value of the surface of the spacer particles, and is not particularly limited. For example, the spacer particles are strong as carboxylic acid groups on the surface. When using a surface having an SP value of 11 or more due to having a hydrophilic group, etc., a combination of the above-mentioned solvents having a high boiling point and a low SP value is combined with a solvent having a low boiling point and a high SP value. The SP value is about 9 to (the SP value of the spacer surface). Such a mixed solvent has a lower SP value as the drying of the droplet proceeds, and the dispersibility of the spacer particles is lowered.
As such a mixed solvent, a solvent satisfying the above conditions may be appropriately selected and used from the above-mentioned solvents. Specifically, as a solvent having a high boiling point and a low SP value, for example, monoalcohol (1 Grade alcohol), monoethers of diols such as glycols, or ethers of diols such as diethers, diols such as glycols having a lower boiling point, water, and the like may be selected.

Further, in the case of using the spacer particles having a surface SP value of about 9 to 11 due to mainly having a moderate hydrophilic group such as a hydroxyl group or an ether group on the surface, And a solvent having a high boiling point and a high SP value combined with a solvent having a low boiling point and a low SP value, and the mixed solvent has an SP value of about (spacer surface SP value) to about 15 or the like. Such a mixed solvent has a higher SP value as the drying of the droplet proceeds, and the dispersibility of the spacer particles is lowered.
As such a mixed solvent, for example, a solvent satisfying the above conditions may be appropriately selected from the above-mentioned solvents, and specifically, a solvent such as glycol having a high boiling point and a high SP value may be used. When water or water is selected, a monoalcohol (primary alcohol) having a lower boiling point than this, a monoether of diol such as glycol, or an ether of diol such as diether may be selected.

When the difference (A) between the SP value in the first drying stage of the droplet and the SP value on the surface of the spacer particles deviates from the above formula (1), the initial dispersibility deteriorates, for example, the spacer dispersion aggregates during storage. For this reason, it is not preferable, and if such a spacer particle dispersion is forcibly used, there is a problem that the apparatus becomes large, such as always requiring ultrasonic irradiation. Further, when the difference (B) between the SP value of the solvent mixture and the SP value of the spacer particle surface in the latter drying stage of the droplet deviates from the above formula (2), the spacer particles in the droplet are dried as the droplet is dried. Becomes difficult to aggregate.

In addition, SP value of the said solvent and mixed solvent, and SP value of the spacer particle | grain surface are the parameters (the said literature Table 3-3 by adhesion) Vol. 40 No. 8 (1996) p342-350 [polymer publication society]. In the case of a mixed solvent, it is a value calculated by calculation using the formulas (2 · 8) of the document, and in the case of the spacer particle surface, formulas (3 · 4) and (3 · 5).
Here, the SP value of the mixed solvent is determined from the blending ratio of the mixed solvent. The SP value of the spacer particle surface is analyzed by TOF-SIMS (time-of-flight secondary ion mass spectrometry), and the monomer surface copolymer is measured (polymer composition). The molar ratio of the monomer type as a component and its monomer unit (for example, “—CH ₂ —CHCOOR—” for an acrylic monomer is calculated by measurement), and is calculated from the measured value. That is, the SP value on the surface of the spacer particles is not calculated by the amount of monomer charged when the spacer is made or the surface of the spacer is modified. This is because even if the monomer mixing ratio and amount are the same, the chemical / physical state of the spacer surface varies depending on the initiator and the polymerization method.

In the mixed solvent of the above (2), the contact angle of the mixed solvent with respect to the spacer particles can be measured with a normal contact angle measuring device by applying the spacer particle dispersion of the present invention on a substrate and drying it. Measured after a certain period of time has elapsed after spacer particles are uniformly spread over an area larger than the area, and the mixed solvent or a solvent (or mixed solvent) having a composition remaining in the late drying stage of the droplet is dropped therein. It is the contact angle of these mixed solvent droplets with the spacer particle group surface. This contact angle can be measured with a general contact angle measuring device that measures the wettability of the surface, and shows the affinity of the solvent on the surface of the spacer particles. That is, it can be said that the lower the contact angle, the more the affinity for the solvent is exhibited. For example, if any of the solvents constituting the mixed solvent has a relatively high affinity with the spacer particle surface, the contact angle will be 0 degrees if left for a long time when the difference is observed. Since it cannot be seen, it is necessary to see the difference in contact angle after a relatively short time since the droplet contacted the spacer particles. In this case, it is preferable to use a contact angle measuring device having a high-speed video camera.
In addition, the contact angle of the liquid droplet photographed with this contact angle measurement device changes with time (from the video image of the droplet spreading wet on the surface of the spacer particles), and the time variation of this contact angle. The rate can also be measured and used as a measure of the wettability of the spacer particle surface. If the time change rate of the contact angle is large, it can be said that the surface of the spacer particles is easily wetted by the mixed solvent (the spacer particles are easily dispersed). When the time change rate of the contact angle is small or the value of the contact angle itself is large, it can be said that the spacer particles are hardly dispersed in those solvents.

When a mixed solvent in which the difference (θs2−θs1) is less than 1 degree (including a negative value) is used, the spacer particles agglomerate in the droplets as the spacer particle dispersion droplets dry. Particles are less likely to aggregate.

Examples of the mixed solvent in which the difference (θs2−θs1) is 1 degree or more include, for example, a solvent having low wettability among the above-described solvents, that is, the solvent itself has high cohesive force (surface tension) It is preferable to select a combination of a solvent having a high boiling point and a lower boiling point and surface tension. Specifically, for example, when a diol such as glycol or water is selected as a solvent having a high boiling point and a high surface tension, for example, monoalcohol (primary alcohol) having a lower boiling point than this, glycol or the like A diol ether such as a diol monoether or a diether may be selected.

In addition, when mixing 3 or more types of solvents (this also applies to the mixed solvent (1) and the mixed solvent (3) described later), the surface tension of the solvent having the middle boiling point may be the highest. However, in such a case, if the surface tension, SP value, and contact angle θs2 in the drying process are larger than the surface tension of the first mixed solvent, the object of the present invention is met.

As the mixed solvent (3), a combination of solvents that increases the zeta potential of the spacer particles before being discharged onto the substrate surface (pre-drying period) is used. That is, even in the same spacer particles, the zeta potential increases when the polarizability or dielectric constant of the solvent is high. Therefore, the mixed solvent is a solvent having a low boiling point, for example, a high polarizability or dielectric constant such as water or glycol. A solvent is mixed, and a solvent having a higher boiling point and lower polarizability and dielectric constant may be added thereto.
Here, the high zeta potential means that the absolute value of the potential is large, and it means that the solvent mixture is set to 0 V and has a positive or negative potential.

In addition, as a method of providing a difference in zeta potential on the surface of the spacer particles in the droplet formed on the surface of the substrate immediately after the droplet is discharged and formed on the surface of the substrate and in the late drying stage of the droplet, In addition to a method of appropriately combining the above solvents, there is a method of performing a chargeable treatment on the spacer particles described later. The spacer particles of the present invention in which the zeta potential on the surface of the spacer particles in the droplet formed on the surface of the substrate has a difference between immediately after the droplet is discharged and formed on the surface of the substrate and the late drying stage of the droplet. In particular, as shown in FIG. 1B, the dispersion liquid does not have a high receding contact angle with respect to the substrate of the spacer particle dispersion liquid of the present invention, and does not reduce the landing diameter of the droplet formed on the surface of the substrate. It is suitable in such a case.

When the zeta potential of the spacer particles in the first drying stage of the droplet is lower than the zeta potential of the spacer particles in the second drying stage of the droplet, the spacer particles are less likely to aggregate in the droplet as the droplet dries.

The mixing ratio of the solvent constituting the mixed solvent is not particularly limited, and is appropriately determined so that the composition changes in the latter drying stage of the droplet.

Further, as the solvent used in the spacer particle dispersion of the present invention, a solvent that is liquid at a temperature discharged from the head of an ink jet apparatus described later is used. A hydrophilic solvent is preferably used. In addition, since the heads of some ink jet apparatuses are made for aqueous media, when these heads are used, a strong hydrophobic solvent may damage the members constituting the head or bond the members. Since a part of the agent may be dissolved, it is not preferable.

Examples of the water-soluble or hydrophilic solvent include, in addition to water, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, 1-hexanol, and 1-methoxy-2- Monoalcohols such as propanol, furfuryl alcohol, tetrahydrofurfuryl alcohol, etc., lower monoalkyl ethers such as propylene glycol, glycol monomethyl ether, monoethyl ether, monoisopropyl ether, monopropyl ether, monobutyl ether; Lower dialkyl ethers such as dipropyl ether; alkyl esters such as monoacetate and diacetate, ether derivatives of diols, acetate derivatives of diols, N, N-dimethylformamide, N, N Diethylformamide, N, N-diethylethanolamine, diacetone alcohol and the like.

In the spacer particle dispersion of the present invention, the solvent (mixed solvent) preferably has an initial contact angle of 5 degrees or more with respect to the substrate on which the spacer particle dispersion of the present invention is discharged using an ink jet apparatus. When the initial contact angle with respect to the substrate is less than 5 degrees, the spacer particle dispersion of the present invention is applied to the substrate in the initial stage of landing the spacer particle dispersion of the present invention on the surface of the substrate, that is, in the first stage of drying the droplets. The spacer particles are difficult to move in the droplets because the upper portion of the spacer particles is exposed from the droplets, and the spacer particles may not aggregate.

In addition, the spacer particle dispersion of the present invention needs to be able to be stably ejected by an ink jet apparatus. Therefore, the above-mentioned solvent (mixed solvent) has a surface tension within a predetermined range, and the ink can be discharged from the ink jet apparatus. The viscosity when discharging the spacer particle dispersion of the invention is preferably within a predetermined range.
Specifically, the preferable lower limit of the surface tension of the solvent (mixed solvent) is 25 mN / m, and the preferable upper limit is 50 mN / m. If the surface tension of the solvent (mixed solvent) at 20 ° C. is outside the above range, the dischargeability and discharge accuracy of the resulting spacer particle dispersion may be insufficient. In particular, when the surface tension is less than 25 mN / m, the nozzle surface of the head of the ink jet apparatus may get wet and the discharge state may become unstable, and the liquid droplets wet and spread on the substrate (landing liquid droplets). The diameter may increase), and the gathering property of the spacer particles may be adversely affected. If it exceeds 50 mN / m, when the head is filled with the spacer particle dispersion liquid, problems such as bubbles are likely to remain in the ink chamber in the head (the ink chamber immediately before the nozzle adjacent to the piezo) and cannot be discharged. There is. However, when the liquid contact part such as the ink chamber in the head of the ink jet apparatus is made of a highly hydrophilic material (for example, SUS, ceramic, glass, etc.) and / or before filling with the spacer particle dispersion liquid. -If the surface of the flow path and the head can be replaced with the spacer particle dispersion liquid after filling with a solvent that wets the ink chamber well, such as propanol, after sufficiently removing the bubbles and preventing the bubbles from getting involved. As described above, although it takes time and effort on facilities and processes, even a spacer particle dispersion liquid having a surface tension exceeding 50 mN / m can be discharged. The viscosity of the solvent (mixed solvent) will be described later.

The spacer particle dispersion of the present invention preferably contains a solvent having a lower limit of boiling point of 100 ° C. and an upper limit of 190 ° C. as the solvent. Furthermore, it is preferable to use only a solvent having a surface tension of 30 mN / m or more as a solvent having a boiling point of 100 ° C. and an upper limit of 190 ° C. By using only a solvent having a surface tension of 38 mN / m or more as a solvent having a boiling point of 100 ° C. and an upper limit of 190 ° C., the initial contact angle of the solvent with respect to the substrate can be 5 degrees or more. The receding contact angle (θr) with respect to the substrate of the spacer particle dispersion of the present invention to be described later can be increased. Furthermore, when the spacer particle dispersion liquid of the present invention is discharged onto the substrate surface, the landing droplet diameter does not increase, the landing droplet diameter is difficult to expand from the initial stage, and the spacer particles easily move toward the center of the landing point. . Therefore, it is possible to selectively and accurately arrange the spacer particles on the substrate. In addition, in this specification, a boiling point means the boiling point on 1 atmosphere conditions.

Examples of the solvent having a lower limit of the boiling point of 100 ° C. and an upper limit of 190 ° C. include, for example, water, 1-butanol, 2-butanol, 2-methyl-1-propanol (isobutyl alcohol), and 1-pentanol. 2-pentanol, 3-pentanol, 2-methyl-1-butanol, 3-methyl-1-butanol (isopentyl alcohol), 2-methyl-2-butanol (tert-pentyl alcohol), 3-methyl- 2-butanol, 2,2-dimethyl-1-propanol (neopentyl alcohol), 1-hexanol, 2-methyl-1-pentanol, 4-methyl-2-pentanol (methyl isobutyl carbinol), 2-ethyl -1-butanol, furfuryl alcohol, tetrahydrofurfuryl alcohol, 1,2-propane All (propylene glycol), ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monoisopropyl ether, ethylene glycol monobutyl ether, ethylene glycol mono t-butyl ether, ethylene glycol diethyl ether, ethylene glycol diacetate (ethylene diacetate), Ethylene glycol monomethyl ether acetate, ethylene glycol monoethyl ether acetate, ethylene glycol monoformate ester, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monobutyl ether, propylene glycol monomethyl ether acetate, prop Pyrene glycol monoethyl ether acetate, propylene glycol monomethyl ether propionate, propylene glycol diacetate, 3-methoxybutanol (1,3-butanediol monomethyl ether), 3-methoxy-3-methyl-1-butanol, diethylene glycol dimethyl ether, Diethylene glycol diethyl ether, diethylene glycol methyl ethyl ether, diethylene glycol methyl isopropyl ether, dipropylene glycol monomethyl ether, dipropylene glycol dimethyl ether, glycerin monoacetate (monoacetin), dioxane, trioxane, n-propyl acetate, butyl acetate, ethyl butyrate, methyl lactate , Ethyl lactate, butyl lactate, dimethyl malonate, ethyl-3 -Ethoxypropionate, 3-methoxybutyl acetate, 3-methyl-3-methoxybutyl acetate, methyl acetoacetate, ethyl acetoacetate, phenol, octane, nonane, decane, toluene, ethylbenzene, DMF, DMSO and the like.

In the spacer particle dispersion of the present invention, the solvent preferably contains a solvent having a boiling point of less than 100 ° C. and a solvent having a boiling point of 100 ° C. or more. By using such a solvent, the surface tension of the spacer particle dispersion of the present invention can be set to 30 mN / m or more. If the surface tension of the spacer particle dispersion of the present invention is lower than 30 mN / m, the droplet diameter of the spacer particle dispersion that has landed on the substrate may be too large. Furthermore, it is preferable to contain an organic solvent having a boiling point of 70 ° C. or more and less than 100 ° C. as the solvent having a boiling point of less than 100 ° C.

When manufacturing a liquid crystal display device using the spacer particle dispersion liquid of the present invention, when the droplets formed by discharging the spacer particle dispersion liquid of the present invention onto the surface of the substrate using an ink jet apparatus described later are dried, When the temperature of the solvent becomes high, the alignment film is contaminated and the display image quality of the liquid crystal display device is impaired, so that the drying temperature cannot be increased too much. For this reason, since the drying temperature can be lowered by using a solvent of less than 100 ° C. as described above, the alignment film is not contaminated.
As the solvent having a boiling point of less than 100 ° C., for example, lower monoalcohols such as ethanol, n-propanol and 2-propanol, acetone and the like are preferably used.

As the blending amount of the solvent having a boiling point of less than 100 ° C., a preferable lower limit is 1.5% by weight and a preferable upper limit is 80% by weight with respect to 100% by weight of the spacer particle dispersion of the present invention excluding the spacer particles. When the liquid crystal display device is produced using the spacer particle dispersion liquid of the present invention when the amount is less than 1.5% by weight, the drying speed is decreased when the droplets of the spacer particle dispersion liquid of the present invention are dried at a relatively low temperature. Slows production efficiency. If it exceeds 80% by weight, the spacer particle dispersion of the present invention in the vicinity of the nozzles of the ink jet apparatus tends to dry, and the ink jetting properties may be impaired. Further, the spacer particle dispersion of the present invention is easily dried in a tank or in a tank, and as a result, there is a high possibility that aggregated particles in which the spacer particles are aggregated are generated.

The solvent having a boiling point of less than 100 ° C. preferably has a surface tension at 20 ° C. of less than 30 mN / m. When the surface tension is 30 mN / m or more, the surface tension of the spacer particle dispersion of the present invention becomes too high, and depending on the surface tension of the liquid contact portion of the ink chamber of the inkjet head, the ejection of the spacer particle dispersion of the present invention by the inkjet device is performed. May be worse. When the spacer particle dispersion liquid of the present invention contains a solvent having a boiling point of less than 100 ° C. and a surface tension of less than 30 mN / m, the spacer particle dispersion liquid of the present invention can be easily introduced into an ink jet apparatus to be described later. In this case, the discharge property can be improved. More preferably, it is 25 mN / m or less.
In addition, it is preferable that the surface tension in 20 degreeC of the solvent whose boiling point is 100 degreeC or more is 30 mN / m or more.

The spacer particle dispersion of the present invention preferably contains a solvent having a boiling point of 100 ° C. or more and 190 ° C. or less together with a solvent having a boiling point of less than 100 ° C. and a surface tension of less than 30 mN / m. The solvent having a temperature of 100 ° C. or more and 190 ° C. or less preferably has a surface tension of 30 mN / m or more. By mixing a solvent having a lower limit of boiling point of 100 ° C., an upper limit of 190 ° C. and a surface tension of 30 mN / m or more, the receding contact angle of the spacer particle dispersion of the present invention described later is further increased. That is, after the droplet made of the spacer particle dispersion liquid of the present invention lands on the substrate, the solvent having a boiling point of less than 100 ° C. having a low surface tension is volatilized first, and the remaining liquid droplets of the spacer particle dispersion liquid of the present invention are left. The surface tension of the spacer increases, and the spacer particles tend to aggregate toward the center of the landing point.

When the surface tension of the solvent having a lower limit of boiling point of 100 ° C. and an upper limit of 190 ° C. is less than 30 mN / m, after the droplet made of the spacer particle dispersion liquid of the present invention has landed on the substrate, the boiling point is less than 100 ° C. Since the solvent having a low surface tension volatilizes first, the surface tension of the spacer particle dispersion of the present invention of the remaining droplets is lower than the initial. Therefore, the diameter of the landing droplet is not reduced, the diameter of the landing droplet is likely to expand from the initial stage, and the spacer particles are less likely to aggregate toward the center of the landing point.

As the material of the spacer particles contained in the spacer particle dispersion of the present invention, a liquid having a gap control characteristic in a liquid crystal display device and, as will be described later, a liquid landed on the surface of a substrate using an ink jet device. When the droplets are dried, there is no particular limitation as long as the spacer particles contained in the droplets are aggregated together. For example, even inorganic particles such as silica particles, organic polymers, etc. Organic particles may be used. Among them, the organic particles have an appropriate hardness that does not damage the alignment film formed on the substrate of the liquid crystal display device, can easily follow a change in thickness due to thermal expansion and contraction, and further, the inside of the cell. This is preferable because it has the advantage that the movement of the spacer particles is relatively small.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

The particle diameter of the spacer particles used in the present invention is not particularly limited because it can be appropriately selected depending on the type of liquid crystal display element to be produced, but the preferred lower limit of the particle diameter of the spacer particles is 1 μm and the preferred upper limit is 20 μm. If it is less than 1 μm, the opposing substrates may come into contact with each other and may not function sufficiently as a spacer of the liquid crystal display element. If it exceeds 20 μm, it will be easy to protrude from the non-pixel region etc. on the substrate on which the spacer particles are to be arranged, and the distance between the opposing substrates will become large enough to meet the recent demand for miniaturization of liquid crystal display elements. It may not be possible.

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

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

The spacer particles preferably have a lower limit of the surface solubility parameter (SP value) δ of 9.50. If it is less than 9.50, it can be dispersed only in a solvent mixture having a relatively low solubility parameter. When a spacer particle dispersion liquid dispersed in such a solvent mixture is discharged onto the substrate, the initial contact angle on the substrate is reduced. Becomes smaller (i.e., the droplet diameter becomes larger), and the spacers do not gather well.

In the spacer particle dispersion of the present invention, the spacer particles are preferably subjected to a surface treatment. By appropriately selecting the composition of the solvent described above in accordance with the surface treatment applied to the spacer particles, the spacer particles are dispersed in the droplets formed by discharging the spacer particle dispersion of the present invention onto the surface of the substrate with an ink jet device. It can be suitably aggregated.
For example, the surface modification of the spacer particles causes the difference between the SP value of the mixed solvent and the SP value of the spacer particle surface to be within 5. When the above mixed solvent is a hydrophilic mixed solvent mainly composed of glycol or water (surface tension is 30 mN / m or more), the surface treatment may be performed so that the spacer surface has a hydrophilic group as a functional group. In the case of a mixed solvent with high hydrophobicity (surface tension of less than 30 mN / m), the spacer surface may be mainly provided with hydrophobicity as a functional group.
In addition, in obtaining the spacer particle surface, the organic fine particles are manufactured as described above, and then the surface is modified, and the compounding and synthesizing method is performed so that such a surface can be formed when forming the organic fine particles. You may devise.

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

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

In addition, by performing the surface treatment in this way, there is an effect that the adhesion of the spacer particles to the substrate is increased, or if the monomer to be used is appropriately selected, the alignment of the liquid crystal in the liquid crystal display body is not disturbed. .

The spacer particles are preferably surface-modified by grafting. Specifically, a vinyl thermoplastic resin obtained by radical polymerization of a vinyl monomer having a hydrophilic functional group and / or an alkyl group having 1 to 22 carbon atoms is bonded to the surface of the spacer particle by graft polymerization. It is preferable.

The hydrophilic functional group is not particularly limited, and examples thereof include a hydroxyl group, a carboxyl group, a sulfonyl group, a phosphonyl group, an amino group, an amide group, an ether group, a thiol group, and a thioether group. Therefore, a hydroxyl group, a carboxyl group, and an ether group are preferably used. These hydrophilic functional groups may be used independently and 2 or more types may be used together. In particular, the spacer particles are preferably surface-modified so that a carboxyl group is present on the surface. In this case, the preferable lower limit of the abundance ratio of the surface of the monomer containing a carboxyl group is 10 mol%. If it is less than 10 mol%, the dispersibility in the spacer particle dispersion liquid becomes low, or the liquid droplets are less likely to aggregate inside the liquid droplets as it dries.

The vinyl monomer having a hydrophilic functional group is not particularly limited. For example, 2-hydroxyethyl (meth) acrylate, 1,4-hydroxybutyl (meth) acrylate, (poly) caprolactone-modified hydroxyethyl (meth) ) Vinyl monomers having a hydroxyl group such as acrylate, allyl alcohol, glycerin monoallyl ether; acrylic acid such as (meth) acrylic acid, α-ethylacrylic acid, crotonic acid, and their α-alkyl derivatives or β-alkyl Derivatives; Unsaturated dicarboxylic acids such as fumaric acid, maleic acid, citraconic acid and itaconic acid; vinyl monomers having a carboxyl group such as mono 2- (meth) acryloyloxyethyl ester derivatives of the above unsaturated dicarboxylic acids; t -Butylacrylamide sulfonic acid, styrene sulfonic acid, A vinyl monomer having a sulfonyl group such as acrylamido-2-methylpropanesulfonic acid; a vinyl monomer having a phosphonyl group such as vinyl phosphate and 2- (meth) acryloyloxyethyl phosphate; dimethylaminoethyl methacrylate; Vinyl monomers having amino groups such as diethylaminoethyl methacrylate; terminal alkyl ether of (poly) ethylene glycol (meth) acrylate, terminal alkyl ether of (poly) propylene glycol (meth) acrylate, tetrahydrofurfuryl (meth) acrylate Vinyl monomers having an ether group such as: (poly) ethylene glycol (meth) acrylate, (poly) propylene glycol (meth) acrylate, etc., a vinyl monomer having a hydroxyl group and an ether group ; (Meth) acrylamide, methylol (meth) acrylamide, vinyl monomers having a amide group such as vinyl pyrrolidone. These vinyl monomers having a hydrophilic functional group may be used alone or in combination of two or more.

It does not specifically limit as said C1-C22 alkyl group, For example, a methyl group, an ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, t-butyl group, n -Pentyl group, n-hexyl group, cyclohexyl group, 2-ethylhexyl group, n-heptyl group, n-octyl group, n-nonyl group, decyl group, undecyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group, Nonadecyl group, eicodecyl group, henicosyl group, docosyl group, isobornyl group and the like can be mentioned. These C3-C22 alkyl groups may be used independently and 2 or more types may be used together.

The vinyl monomer having an alkyl group having 1 to 22 carbon atoms is not particularly limited. For example, an ester compound composed of (meth) acrylic acid and the alkyl group having 1 to 22 carbon atoms; vinyl alcohol and the above Examples thereof include ester compounds composed of an alkyl group having 1 to 22 carbon atoms; vinyl ether compounds composed of a vinyl group and the above alkyl group having 1 to 22 carbon atoms. These vinyl monomers having an alkyl group having 1 to 22 carbon atoms may be used alone or in combination of two or more.
The vinyl monomer having a hydrophilic functional group and the vinyl monomer having an alkyl group having 1 to 22 carbon atoms may be used alone, or both may be used in combination.

The vinyl thermoplastic resin contains 15 to 80 mol% of a vinyl monomer having a hydrophilic functional group as a constituent vinyl monomer, and has an alkyl group having 1 to 22 carbon atoms. It is preferable to contain 5 to 60 mol% of a vinyl monomer. In addition, the mol% here is not the mol% of the charge at the time of polymerization when performing surface treatment using these monomers, but the monomer unit of the copolymer present on the surface measured by a method such as TOF-SIMS. Mol% of (monomer fragment).

When the content of the vinyl monomer having a hydrophilic functional group in the vinyl monomer is less than 15 mol%, the obtained spacer particles are sufficiently single particles in the spacer particle dispersion of the present invention. The liquid crystal display device manufactured using the spacer particle dispersion liquid of the present invention is difficult to disperse in a converted state, and agglomerated particles are likely to be generated, making it difficult to stably discharge the ink jet device. The cell gap may not be formed accurately. When the content of the vinyl monomer having a hydrophilic functional group in the vinyl monomer exceeds 80 mol%, a cell of a liquid crystal display device is formed using the spacer particle dispersion of the present invention. The surface of the spacer particles that protrude into the display pixel is liable to cause abnormal alignment of the liquid crystal, leading to deterioration in display quality of the liquid crystal display device to be manufactured.

Further, when the content of the vinyl monomer having an alkyl group having 1 to 22 carbon atoms in the vinyl monomer is less than 5 mol%, the liquid crystal display device using the spacer particle dispersion of the present invention is used. When the cell is formed, the liquid crystal display device is likely to be abnormally aligned on the surface of the spacer that protrudes into the display pixel, leading to deterioration of the display quality of the liquid crystal display device to be manufactured. If the content of the vinyl monomer having an alkyl group having 1 to 22 carbon atoms exceeds 60 mol%, the dispersion stability of the resulting spacer particles in the solvent may be lowered.

The spacer particles are bonded by graft polymerization with a vinyl thermoplastic resin obtained by radical polymerization of the vinyl monomer having the hydrophilic functional group and / or the alkyl group having 1 to 22 carbon atoms on the surface of the spacer particles. When laminating a plurality of vinyl thermoplastic resin layers having different compositions for the purpose of increasing the thickness of the particle surface coating layer, the vinyl monomer having the hydrophilic functional group is added in an amount of 15 to 80 mol%. The use of a preferable vinyl monomer containing 5 to 60 mol% of the above-mentioned vinyl monomer having an alkyl group having 1 to 22 carbon atoms is a vinyl heat that becomes the outermost layer of the surface coating layer. Only the plastic resin need be considered. This is because the functions such as the dispersibility of the spacer particle dispersion and the medium used in the ink-jet ink and the suppression of abnormal liquid crystal orientation are manifested by the state near the surface of the spacer.
By performing such a surface treatment, spacer movement is eliminated in an impact test or the like after the panel is manufactured.

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

Examples of a method for performing chargeable treatment on the spacer particles include, for example, a method of containing a charge control agent in the spacer particles, a method of manufacturing spacer particles from a monomer containing a monomer that is easily charged, and the surface described above. For example, a method of performing a surface treatment capable of charging the spacer particles by using a method of performing the treatment may be used.
In addition, when the spacer particles can be charged in this way, not only the dispersibility and dispersion stability of the spacer particles in the spacer particle dispersion liquid of the present invention are improved, but also the wiring portion (step difference) due to the electrophoretic effect at the time of spraying. There is also an effect that the spacer particles are likely to gather near the portion.

As a method of containing the charge control agent, there are a method in which the charge control agent is allowed to coexist when polymerizing the spacer particles and the polymerization is performed in the spacer particles, and a monomer constituting the spacer particles when the spacer particles are polymerized. A charge control agent having a functional group copolymerizable with a monomer constituting a spacer particle and containing the charge controlling agent in the spacer particle, a monomer used for surface modification in the above-described surface modification of the spacer particle A method of copolymerizing a charge control agent having a functional group copolymerizable with a surface modification layer into a surface modification layer, reacting charged particles having a functional group that reacts with the surface modification layer or the surface functional group of spacer particles on the surface The method of making it contain etc. are mentioned.

It does not specifically limit as said charge control agent, For example, the compound as described in Unexamined-Japanese-Patent No. 2002-148865 can be used. Specifically, for example, organometallic compounds, chelate compounds, monoazo dye metal compounds, acetylacetone metal compounds, aromatic hydroxyl carboxylic acids, aromatic mono and polycarboxylic acids and their metal salts, anhydrides, esters, bisphenols, etc. Phenol derivatives and the like.

Further, the charge control agent is not particularly limited, but urea derivatives, metal-containing salicylic acid compounds, quaternary ammonium salts, calixarene, silicon compounds, styrene-acrylic acid copolymers, styrene-methacrylic acid copolymers, styrene -Acrylic-sulfonic acid copolymer, non-metal carboxylic acid compound, modified product with nigrosine and fatty acid metal salt, 4 such as tributylbenzylammonium-1-hydroxy-4-naphthosulfonate, tetrabutylammonium tetrafluoroborate Onium salts such as quaternary ammonium salts and their analogs such as phosphonium salts and lake pigments thereof, triphenylmethane dyes and lake lake pigments (as rake agents, phosphotungstic acid, phosphomolybdic acid, phosphotungsten) Molybdic acid, Ninnic acid, lauric acid, gallic acid, ferricyanide, ferrocyanide, etc.), metal salts of higher fatty acids, diorganotin oxides such as dibutyltin oxide, dioctyltin oxide, dicyclohexyltin oxide, dibutyltin borate, dioctyltin Diorganotin borates such as borate and dicyclohexyl tin borate are preferably used.
These charge control agents may be used independently and 2 or more types may be used together.

The polarity of the spacer particles containing the charge control agent can be set by appropriately selecting an appropriate one from the charge control agents. That is, the spacer particles can be charged positively or negatively with respect to the surrounding environment.

When producing the spacer particles, as a method for selecting a monomer appropriately from monomers including monomers that are easily charged, the monomer for producing the spacer particles described above has a hydrophilic functional group. The method of using these in combination. By appropriately selecting an appropriate monomer from these monomers having a hydrophilic functional group, the spacer particles can be charged positively or negatively with respect to the surrounding environment. .

In addition to these, the spacer particles are easily moved on the substrate when the droplet ends of the spacer particle dispersion liquid of the present invention discharged on the substrate surface or in the droplet are shrunk. Because of the demand to firmly fix after drying, not only the surface treatment of the spacer particles as described above, but also the surface state of the spacer particles, or when performing the surface treatment It is necessary to pay attention to the thickness and the shape of the surface obtained.
That is, if the surface of the spacer particles is too uneven, or if the surface treatment layer is swollen in the droplets, the spacer particles are difficult to move in the droplets. There are chemical interactions such as the surface composition of the spacer particles in the inside being close to the surface composition of the substrate, and there is a strong electrostatic interaction between the spacer particles and the substrate in the droplets. Then, similarly, the spacer particles are difficult to move, and as a result, the aggregation of the spacer particles in the droplet described later is difficult to occur.

The spacer particle dispersion of the present invention is obtained by dispersing the spacer particles in the above-described solvent (mixed solvent). Among them, the spacer particles have a carboxyl group on the surface, and are formed on the substrate surface. When the weight of the droplets formed by discharge is reduced by 5% by weight or more (late drying stage), the solvent preferably contains 10% by weight or more of water and a solvent having a boiling point of 190 ° C. or lower. Since the spacer particles have a carboxyl group on the surface, they have excellent dispersibility in a mixed solvent of the above water and a solvent having a boiling point of 190 ° C. or less, and are excellent in cohesiveness in the late drying stage of the droplets. And a solvent having a boiling point of 190 ° C. or lower can prevent the droplets from spreading out immediately after the formation. Further, if the mixed solvent of water and a solvent having a boiling point of 190 ° C. or lower in the latter stage of drying is less than 10% by weight, the mixed solvent decreases before the spacer particles are sufficiently aggregated, and the spacer particles May not be able to aggregate at the location.

The spacer particle dispersion of the present invention comprising such a solvent and the spacer particles, the impact diameter D ₁ of the droplets of the liquid just discharged to the surface of the substrate, the weight of the liquid droplets ejected on the surface of the substrate 5 and aggregate diameter D ₂ of the spacer particles upon reduction wt% or more, it is preferable, wherein the following formula (1).

D ₂ <(D ₁ × 0.5) (1)

Note that the aggregate diameter D ₂ of the spacer particles, when the spacer particles aggregate in the droplets of the spacer particle dispersion of the present invention in plan view, means the diameter of a circle inscribed in aggregated spacer particles.

The formula (1) is agglomerated diameter D ₂ of the spacer particles, meaning that less than half of the landing diameter D ₁ of the said droplet. If no relationship of the above formula (1), i.e., agglomerated diameter D ₂ of the spacer particles, if it is 1/2 or more landing diameter D ₁ of the said droplet, the spacer particle dispersion of the present invention When the amount of the spacer particles contained is too large, or the spacer particles are not sufficiently aggregated in the late drying stage of the droplets, and the liquid crystal display device is manufactured using the spacer particle dispersion of the present invention. The spacer particles may be disposed in the non-pixel region on the substrate, and the display image quality of the obtained liquid crystal display device may be inferior.

The spacer particle dispersion of the present invention preferably has a viscosity during storage (20 ° C.) of greater than 3 mPa · s and less than 20 mPa · s. When the pressure is 3 mPa · s or less, the spacer particles dispersed in the spacer particle dispersion of the present invention are likely to settle over time, and a low-viscosity and difficult-to-discharge head is provided with a cooling mechanism to increase the viscosity. However, there arises a problem that the viscosity cannot be discharged. When it is 20 mPa · s or more, when discharging using an inkjet apparatus, the head may be heated, and it may not be possible to discharge with a type of head that cannot lower the viscosity, or the discharge amount may be difficult to control. Occasionally, the spacer particle dispersion may need to be overheated to further improve ejection properties.
In addition, when using the head which can be heated, the preferable upper limit of the said viscosity is 100 mPa * s. This is because, even if the temperature can be increased, if the temperature is too high so as to lower the viscosity, the spacer particle dispersion and the head deteriorate, so that the temperature can only be increased up to about 60 ° C. More preferably, it is less than 20 mPa · s when heated to about 60 ° C.
Moreover, the preferable minimum of the viscosity at the time of discharge of the spacer particle dispersion liquid of this invention is 0.5 mPa * s, and a preferable upper limit is 20 mPa * s. If it is less than 0.5 mPa · s, even if it can be discharged, it may be difficult to control the discharge amount, and it may become impossible to discharge stably, and if it exceeds 20 mPa · s, it may not be able to be discharged by the ink jet device. . A more preferred lower limit is 5 mPa · s, and a more preferred upper limit is 15 mPa · s.
Here, the viscosity at the time of discharge means that when discharging the spacer particle dispersion of the present invention, the head temperature of the ink jet device is cooled by a Peltier element or a refrigerant, or heated by a heater or the like, It is the viscosity which adjusted the liquid temperature at the time of discharge of a spacer particle dispersion liquid between -5 degreeC and 50 degreeC. Of course, this is the ambient temperature for a head without a cooling and heating mechanism.
That is, the viscosity during storage of the spacer particle dispersion is preferably as high as possible within the range of the viscosity that can be discharged by the head in any case of not controlling the viscosity at the time of discharge by heating and cooling, etc. from the viewpoint of preventing sedimentation. .
These viscosities were measured at respective temperatures (measurement temperature and use temperature) with ordinary viscometers such as E-type viscometers and B-type viscometers.

In the spacer particle dispersion of the present invention, the specific gravity at 20 ° C. of the solvent mixture constituting the spacer particle dispersion is preferably 1.00 g / cm ³ or more. If it is less than 1.00 g / cm ³ , the spacer particles dispersed in the spacer particle dispersion of the present invention are likely to settle over time.

The spacer particle dispersion of the present invention preferably has a settling rate of spacer particles of 30 minutes or more. The settling speed of the spacer particles can be adjusted by appropriately setting the type and blending amount of the solvent contained in the spacer particle dispersion of the present invention, and the settling speed is 150 minutes or more. The spacer particles are less likely to settle during the period from the introduction of the spacer particle dispersion liquid into the ink jet apparatus until the discharge. Therefore, the spacer particle dispersion liquid of the present invention can be stably discharged using an ink jet device, and the spacer particles can be selectively and accurately arranged on the substrate. In this specification, “sedimentation velocity” means that the spacer particle dispersion of the present invention is introduced into a test tube having an inner diameter of 5 mm so as to have a height of 10 cm and then left to stand visually. The time until the deposition of spacer particles is confirmed at the bottom.

In addition, the spacer particle dispersion of the present invention preferably has a receding contact angle (θr) of 5 degrees or more with respect to the substrate to be discharged. If the receding contact angle is 5 degrees or more, the droplets of the spacer particle dispersion that have landed on the substrate dries and shrinks toward the center, and at least one spacer particle contained in the droplets. It is possible to gather near the center of the droplet (see FIG. 1A). In addition, if charged ink due to electrostatically acting force is landed at the center in advance, or if there is a step within the diameter of the landed droplet, the movement of the spacer particles is more likely to occur. The accuracy is further improved.
The “retreat contact angle” is the first time the droplet of the spacer particle dispersion liquid of the present invention placed on the substrate is placed on the substrate until it is dried. This is the contact angle indicated when the impact diameter starts to be smaller (when the droplet begins to shrink) or the contact angle indicated when 80 to 95% by weight of the volatile component of the droplet has volatilized.

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

In order to set the receding contact angle (θr) of the spacer particle dispersion of the present invention to 5 ° or more, the receding contact angle (θr) of the solvent having the highest boiling point among the mixed solvents is 5 ° or more. Mix so that When the receding contact angle (θr) of the solvent having the highest boiling point is 5 degrees or more, the droplet diameter becomes small in the latter stage of drying (the droplet shrinks on the substrate), and the spacer particles are further on the landing center on the substrate. It becomes easy to gather together.

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

The spacer particle dispersion of the present invention preferably has an initial contact angle θ with the substrate surface of 5 degrees or more. If it is less than 5 degrees, the droplets of the spacer particle dispersion liquid of the present invention discharged onto the substrate may be in a state of being wet spread on the substrate, and the arrangement interval of the spacer particles may not be reduced. More preferably, the initial contact angle with the substrate surface of the spacer particle dispersion of the present invention is adjusted to be 10 to 110 degrees. If it is larger than 110 degrees, the liquid droplets are likely to move around on the substrate with a slight vibration, and as a result, the placement accuracy may deteriorate and the adhesion between the spacer particles and the substrate may deteriorate.

The preferable lower limit of the solid content concentration of the spacer particles in the spacer particle dispersion of the present invention is 0.01% by weight, and the preferable upper limit is 10% by weight. If it is less than 0.01% by weight, there is a high probability that the ejected droplets do not contain spacer particles. If it exceeds 10% by weight, the nozzles of the ink jet apparatus may be easily blocked, and landing The number of spacer particles contained in the dispersed droplets becomes too large, and the spacer particles are less likely to move during the drying process. A more preferred lower limit is 0.1% by weight, and a more preferred upper limit is 3% by weight.
Further, the spacer in the spacer particle dispersion may be used by mixing two or more kinds of particles having different particle diameters when necessary for the gap stability of the substrate.

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

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

The ink jet apparatus for discharging the spacer particle dispersion liquid of the present invention to the surface of the substrate is not particularly limited. For example, a piezo system that discharges liquid by vibration of a piezo element, and liquid expansion by rapid expansion of liquid. An ink jet apparatus using a normal discharge method such as a thermal method for discharging is used. Among them, a piezo method with little thermal influence on the spacer particle dispersion of the present invention is preferably used.

It is preferable that the liquid contact portion of the ink chamber containing the spacer particle dispersion of the present invention of the ink jet apparatus is made of a hydrophilic material having a surface tension of 31 mN / m or more. As the material, a hydrophilic organic material such as hydrophilic polyimide is used, or a head made of a material of a liquid contact part of a normal ink chamber is treated with a hydrophilizing agent (oxidized by the material of the liquid contact part). In addition, an inorganic material is used from the viewpoint of durability.

In a normal head, a resin or the like is used in this portion for insulation from a voltage application component. However, in a material having a surface tension lower than 31 mN / m, the spacer particle dispersion of the present invention is used for the head. At the time of introduction, since the familiarity with the spacer particle dispersion is poor, bubbles are likely to remain. If bubbles remain, the nozzle in which the bubbles remain may not be ejected, which is not preferable.

The nozzle diameter of the ink jet apparatus is preferably 5 times or more the spacer particle diameter. If it is less than 5 times, the nozzle diameter is too small compared to the particle diameter and the discharge accuracy is lowered, and if it is remarkable, the nozzle is blocked and discharge is not preferable. More preferably, it is 7 times or more. The reason why the discharge accuracy is lowered is considered as follows.

That is, in the piezo method, ink is sucked into the ink chamber adjacent to the piezo element due to the vibration of the piezo element, or the ink is ejected from the ink chamber through the tip of the nozzle. As a droplet discharge method, a meniscus (interface between ink and gas) at the tip of the nozzle is pulled in immediately before discharge, and then the liquid is pushed out and the liquid is pushed out directly from the position where the meniscus is on standby Although there is a method, in the general ink jet apparatus, the former striking method is the mainstream, and as a feature thereof, small droplets can be ejected. In the discharge of the spacer particle dispersion liquid of the present invention, the diameter of the nozzle is somewhat large and the discharge of small droplets is required, so this striking method is effective.
However, in the case of the pulling method, the meniscus is pulled in immediately before discharge, so that, for example, when the nozzle diameter is small, such as less than five times the spacer particle diameter, the drawing is performed as shown in FIG. If the spacer particles 1 are present in the vicinity of the meniscus 2, the meniscus 2 is not drawn in an axisymmetric manner. Therefore, it is considered that the liquid droplets of the spacer particle dispersion liquid 3 are not straight but bent during the extrusion after the drawing, and the discharge accuracy is lowered. For example, when the nozzle diameter is large such that the nozzle diameter is 7 times or more of the spacer particle diameter, even if the spacer particle 1 exists in the vicinity of the drawn meniscus 2 as shown in FIG. Not receive. Therefore, it is considered that the meniscus 2 is drawn in an axisymmetric manner, and the liquid droplets of the spacer particle dispersion liquid 3 go straight in the push-out after the pull-in to improve the discharge accuracy. However, if the nozzle diameter is unnecessarily increased in order to eliminate the bending of the droplets during ejection, the ejected droplets become larger and the landing diameter becomes larger. Therefore, the accuracy with which the charged ink and spacer particles 1 are arranged is improved. It becomes rough and is not preferable.

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

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

The interval between the nozzles is restricted by the structure of the piezoelectric element and the nozzle diameter. Accordingly, when the spacer particle dispersion of the present invention is discharged onto the substrate at intervals other than the intervals at which the nozzles are arranged, it is difficult to prepare a head at each discharge interval. Accordingly, when the distance is smaller than the distance between the heads, the head, which is normally arranged at right angles to the scanning direction of the head, is discharged while being tilted or rotated in a plane parallel to the substrate while being parallel to the substrate. When the interval is larger than the interval between the heads, the discharge is not performed by all the nozzles, but is performed by discharging only a certain nozzle, or by additionally tilting the head.
In order to increase productivity, a plurality of such heads can be attached to the ink jet apparatus. However, if the number of attachments is increased, the control becomes complicated, so care must be taken.

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

In the head 100, since the temperature control means 105 is provided, when the viscosity of the spacer particle dispersion of the present invention is too high, the spacer particle dispersion of the present invention can be heated to reduce the viscosity. Is too low, the spacer particle dispersion of the present invention can be cooled by Peltier to increase the viscosity.

The substrate for discharging the spacer particle dispersion of the present invention using the inkjet device is not particularly limited, and for example, a substrate such as glass or a resin plate that is usually used as a panel substrate of a liquid crystal display device can be used.
In the case of manufacturing a liquid crystal display device using the spacer particle dispersion of the present invention, two substrates are used. As one substrate, a substrate provided with a color filter in a pixel region can be used. In this case, the pixel region is defined by a black matrix such as a resin in which a metal such as chrome or carbon black that hardly transmits light is dispersed. This black matrix constitutes a non-pixel region.

The spacer particle dispersion of the present invention preferably reduces the weight of the droplets by 5% by weight or more before the droplets are completely dried in the step of drying the droplets formed by discharging onto the surface of the substrate. When this is done, the spacer particles in the droplets aggregate. Therefore, the spacer particles can be selectively and accurately placed at a target position on the substrate using an ink jet apparatus.
Such a spacer particle dispersion of the present invention can be suitably used in the method for producing a liquid crystal display device of the present invention.

The method for manufacturing a liquid crystal display device of the present invention is a method for manufacturing a liquid crystal display device having a pixel region and a non-pixel region, and spacer particles are formed on the surface of the first substrate or the second substrate using an ink jet device. Disposing the spacer particle dispersion liquid droplets at a specific position corresponding to the non-pixel region by discharging the dispersion liquid, Step 1 aggregating the spacer particles in the spacer particle dispersion liquid droplets 2 And a step 3 of superimposing the first substrate and the second substrate so as to face each other through the liquid crystal and the agglomerated spacer particles.

The method for manufacturing a liquid crystal display device of the present invention is to manufacture a liquid crystal display device having a pixel region and a non-pixel region.
Examples of the liquid crystal display device having the pixel region and the non-pixel region include the liquid crystal display device having the structure described with reference to FIG. 9, and examples of the pixel region include a region where a color filter is formed. Examples of the non-pixel region include a region where a black matrix is formed.

In the method for manufacturing a liquid crystal display device of the present invention, the spacer particle dispersion is discharged onto the surface of the first substrate or the second substrate using an ink jet device, so that the liquid crystal display device is placed at a specific position corresponding to the non-pixel region. A step 1 of disposing droplets of the spacer particle dispersion;

The first substrate or the second substrate is not particularly limited, and examples thereof include conventionally known color filter substrates and TFT array substrates that constitute liquid crystal display devices.

In step 1, the spacer particle dispersion is discharged onto the surface of the first substrate or the second substrate using an ink jet apparatus. At this time, it is more preferable that the location where the droplets of the spacer particle dispersion are discharged and landed on the substrate is adjusted so that the initial contact angle of the spacer particle dispersion is 5 degrees or more.

Examples of the method for increasing the initial contact angle on the substrate include a method in which the surface of the substrate is a low energy surface.
As a method for making the surface of the substrate a low energy surface, a method of coating a resin having a low energy surface such as a fluorine film or a silicone film may be used. Since it is necessary to regulate, a method of providing a resin thin film (usually 0.1 μm or less) called an alignment film is generally performed.

A polyimide resin film is usually used for the alignment film, and the polyimide resin film is obtained by applying a polyamic acid soluble in a solvent and then thermally polymerizing it, or applying a soluble polyimide resin and then drying it. .
As these polyimide resins, those having a long side chain and a main chain are more preferable for obtaining a low energy surface.
The alignment film may be rubbed on the surface after coating in order to control the alignment of the liquid crystal. In addition, it is necessary to select the medium of the above-described spacer particle dispersion liquid that does not contaminate the alignment film by permeating or dissolving in the alignment film.

In the present invention, the first substrate or the second substrate to which the spacer particle dispersion is discharged has a portion having a low energy surface in the region corresponding to the non-pixel region, and the liquid after landing The droplets of the spacer particle dispersion are landed so that the droplets are present at locations having a low energy surface. Here, the region corresponding to the non-pixel region is the non-pixel region (the above-described black matrix for a color filter substrate) or the other substrate (a TFT array substrate for a TFT liquid crystal panel). When the substrate is overlapped with a substrate having a non-pixel region, it indicates one of regions corresponding to the region having the non-pixel region (such as a wiring portion in the case of a TFT array substrate).

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

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

In the present invention, the first substrate or the second substrate to which the spacer particle dispersion is discharged has a portion having a low energy surface in the region corresponding to the non-pixel region, and the droplet after landing However, although the droplets of the spacer particle dispersion liquid are landed so as to be present at a portion having a low energy surface, a portion having a step with the periphery may be included therein. In addition, it is more preferable that the charged ink is discharged and dried only at a portion having a step.

Here, the step is an unintentional unevenness (level difference from the surroundings) caused by wiring provided on the substrate, or intentionally provided to collect spacer particles as in the present invention. The structure below the uneven surface is not important. Therefore, the step here refers to a step between a concave portion or a convex portion and a flat portion (reference surface) in the surface uneven shape.

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

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

As for the action of the step, if there is a step, the droplet drying center is artificially fixed to the step portion at the final stage of drying, so the spacer particle dispersion liquid droplets are dried and then the spacer particles are dried. Can be collected at a very limited position around the step in the region corresponding to the non-pixel region.
In this case, as shown in FIG. 4, the position where the spacer particles 11 finally remain after drying is often a corner if it is a convex part, or in a recess if it is a concave part.

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

In Step 1, the spacer particle dispersion is discharged to a specific position corresponding to the non-pixel region of the substrate described above using an inkjet device. Specifically, the spacer particle dispersion is discharged to a position including a non-pixel region on the surface of the substrate.

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

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

If the droplets are ejected at an interval smaller than the above formula (1), the droplet diameter remains large, the landing diameter also increases and droplet coalescence occurs, and the aggregation direction of the spacer particles occurs toward one place during the drying process. Disappear. As a result, there arises a problem that the arrangement accuracy of the spacer particles after drying is deteriorated. In addition, when the nozzle diameter is reduced in order to reduce the discharge droplet amount, the spacer particle diameter is relatively larger than the nozzle diameter. Therefore, as described in the spacer particle of the present invention, it is more stable than the inkjet head nozzle. For example, the spacer particles cannot always be ejected linearly in the same direction, and the landing position accuracy decreases due to the flight bend. Further, the nozzle may be blocked by the spacer particles. FIG. 11 is a schematic view showing a state in which the spacer particle dispersion is discharged onto the substrate by the above-described method and disposed after drying described later.
However, it is possible to arrange the droplets so as to overlap only in one direction, depending on the surface condition. That is, preferably on the substrate surface where the contact angle and receding contact angle are not so high, the droplets do not coalesce on a circle, but only in that direction, and adhere in a rod shape. After drying, the spacers can be arranged in a linear or broken line only in that direction. FIG. 12 is a schematic view showing a state in which a spacer particle dispersion is discharged onto a substrate by such a method and disposed through drying described later.

It is preferable that the arrangement number (dispersion density) of the spacer particles discharged and arranged on the substrate as in the above formula (2) is usually 50 to 1000 / mm ² . More preferably from 50 to 350 pieces / mm ^2. The spray density is appropriately adjusted depending on the substrate to be arranged, the gap to be obtained and the difference in the particle diameter of the spacer used. Generally, when it is desired to reduce the deformation amount of the spacer (the difference between the gap to be obtained and the particle diameter of the spacer to be used) as much as possible, the appropriate value of the spraying density is preferably 150 to 1000 / mm ^2. . Any pattern may be arranged in any part of the region corresponding to the non-pixel region such as black matrix and the non-pixel region such as wiring as long as the particle density is satisfied. However, in order to prevent protrusion to the display portion (pixel region), for a color filter composed of a lattice-shaped light-shielding region (non-pixel region), the lattice point of the lattice-shaped light-shielding region on one substrate It is more preferable to arrange for the corresponding part.
The number of spacer particles at one arrangement position varies depending on the arrangement position, but is generally about 0 to 20, and the average number is about 2 to 6. The average number is adjusted by the particle diameter of the spacer particles and the concentration of the spacer particle dispersion.

Further, in this way, in order to discharge the spacer particle dispersion and land the droplets on the substrate, the inkjet head can be scanned once or divided into a plurality of times. In particular, when the interval at which the spacer particles are to be arranged is narrower than the above formula (2), the particles are discharged at an integral multiple of the interval, dried once, shifted by the interval, and then discharged again. May be. With respect to the moving (scanning) direction as well, it can be alternately changed (reciprocating discharge) for each discharge and discharged only when moving in one direction (unidirectional discharge).

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

In this step 1, the substrate surface temperature when the spacer particle dispersion is landed on the substrate is preferably 20 ° C. or more lower than the boiling point of the lowest boiling solvent contained in the spacer particle dispersion. When the temperature is higher by 20 ° C. than the boiling point of the lowest boiling point solvent, the lowest boiling point solvent volatilizes rapidly, and not only the spacer particles cannot move. And the spacer particle placement accuracy may be significantly reduced. More preferably, it is around room temperature (15 to 35 ° C.).

The manufacturing method of the liquid crystal display device of the present invention includes the step 2 of aggregating the spacer particles in the droplets of the spacer particle dispersion.
In this step 2, the spacer particles are aggregated in the droplets of the spacer particle dispersion liquid arranged in a specific position corresponding to the non-pixel region on the substrate in the step 1. Specifically, the solvent in the droplet is dried. By using the above-described spacer particle dispersion of the present invention as the spacer particle dispersion, the spacer particles can be aggregated by drying such droplets.

The method of drying the droplets is not particularly limited, and examples thereof include a method of heating the substrate, blowing hot air or cold air, or drying under reduced pressure. However, in order to gather the spacer particles in the vicinity of the droplet landing center in Step 2, the boiling point of the solvent, the drying temperature, the drying time, the surface tension of the solvent, the contact angle of the solvent with respect to the alignment film, the concentration of the spacer particles, etc. Is preferably set to an appropriate condition.

In order to agglomerate the spacer particles in the droplets in this step 2, the spacer particles are dried with a certain time width so that the solvent does not run out while the spacer particles move on the substrate. For this reason, the conditions for the solvent to dry rapidly are not preferred.
In addition, the solvent is not preferable if it contacts the alignment film at a high temperature because the alignment film may be contaminated and the display image quality of the liquid crystal display device may be impaired. Accordingly, the substrate surface temperature until the drying is completed is preferably 90 ° C. or less, more preferably 60 ° C. or less. If the substrate temperature until the drying is completed exceeds 90 ° C., the alignment film may be damaged and the display image quality of the liquid crystal display device may be impaired.

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

Further, even when the substrate temperature is relatively low, not only the production efficiency of the liquid crystal display device is lowered when the drying time is remarkably increased, but also the solvent of the spacer particle dispersion liquid is in contact with the alignment film for a long time. This is not preferable because the alignment film is contaminated or damaged by the above.

In addition, when the droplets are dried while gradually increasing the substrate temperature in this step 2, the substrate surface temperature until the drying is completed is preferably 90 ° C. or less, more preferably 60 ° C. or less. . If the substrate temperature until the drying is completed exceeds 90 ° C., it is not preferable because the alignment film is damaged and the display image quality of the liquid crystal display device is impaired.

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

In Step 2, after the drying of the droplets is completed, the spacer particles can be fixed to the substrate or the residual solvent can be removed. Therefore, even if the substrate is heated to a higher temperature (about 120 to 230 ° C.). Good.

The manufacturing method of the liquid crystal display device of the present invention includes the step 3 of superimposing the first substrate and the second substrate so as to face each other through the liquid crystal and the agglomerated spacer particles.

Specifically, in this step 3, the substrate on which the spacer particles are arranged in the above step 2 is thermocompression-bonded using a substrate on which the spacer particles are not arranged and a peripheral sealing agent, and is formed in the gap between the formed substrates. A liquid crystal display device is manufactured by filling the liquid crystal (vacuum injection method). Alternatively, a peripheral sealing agent is applied to one substrate, a liquid crystal is dropped within a range surrounded by the substrate, and the liquid crystal display device is manufactured by bonding the other substrate and curing the sealing agent (liquid crystal dropping method) ). In this case, spacer particles may be disposed on any substrate.

According to the method for manufacturing a liquid crystal display device of the present invention, a non-pixel of a liquid crystal display device intended for spacer particles is obtained by aggregating spacer particles in droplets formed by discharging a spacer particle dispersion onto the surface of a substrate. It can arrange suitably in a field. In particular, by using the spacer particle dispersion liquid of the present invention as the spacer particle dispersion liquid, the manufactured liquid crystal display device is excellent in display quality without spacer particles being arranged in the pixel region.
A liquid crystal device using the spacer particle dispersion of the present invention or the method for producing a liquid crystal display device of the present invention is also one aspect of the present invention.

The spacer particle dispersion of the present invention is preferably used in the step of drying the droplets formed by discharging onto the surface of the substrate before the droplets are completely dried, preferably when the weight of the droplets is reduced by 5% by weight or more. In addition, since the spacer particles in the droplets are aggregated, the spacer particles can be selectively and accurately placed at a target position on the substrate using an ink jet apparatus.
Moreover, since the lower limit of the boiling point of the solvent is 50 ° C. and the upper limit is 190 ° C., the droplets formed on the substrate surface can be quickly dried.
In addition, according to the method for manufacturing a liquid crystal display device of the present invention, the liquid droplets are disposed at positions corresponding to the non-pixel regions by discharging the spacer particle dispersion liquid onto the surface of the first substrate or the second substrate using an ink jet device. The spacer particles can be disposed in a non-pixel region on the substrate because the spacer particles are dried and the spacer particles in the droplets are aggregated. In particular, by using the spacer particle dispersion liquid of the present invention as the spacer particle dispersion liquid, the spacer particles can be suitably arranged in the non-pixel region on the substrate, and the liquid crystal display device to be manufactured has spacer particles in the pixel region. It is not arranged and the display quality is excellent.
According to the present invention, a spacer particle dispersion, a liquid crystal display capable of quickly and selectively arranging spacer particles at a specific position corresponding to a non-pixel region on a substrate using an inkjet device. A device manufacturing method and a liquid crystal display device can be provided.

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

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

(Surface modification of spacer particles)
5 parts by weight of the obtained spacer particles having an average particle diameter of 4.0 μm and a CV value of 3.0% are put into a total of 20 parts by weight of monomers having the blending ratio shown in Table 1 below, and are uniformly mixed by a sonicator. Dispersed. Thereafter, nitrogen gas was introduced into the reaction system and stirring was continued at 30 ° C. for 2 hours.
Next, 10 parts by weight of a 0.1 mol / L ceric ammonium nitrate solution prepared with a 1N nitric acid aqueous solution was added, and the reaction was continued for 5 hours. After completion of the reaction, the particles and the reaction solution were separated by filtration with a 2 μm membrane filter. The particles were sufficiently washed with ethanol and acetone and dried under reduced pressure in a vacuum drier to obtain surface-modified spacer particles S1, S2, S3, S4 and RS1.

Dispersibility of the mixed solvent used in the spacer particle dispersion liquid of the spacer particles thus obtained and the mixed solvent remaining in the late drying stage, and mixing used in the spacer particle dispersion liquid with respect to the spacer particles The contact angle between the solvent and the mixed solvent remaining in the late stage of drying was evaluated as follows. The results are shown in Tables 2 and 3.

(Preparation of solvent mixture remaining in late drying stage)
5 g of the solvent mixture having the composition described in Table 4 below is dried at a temperature (45 ° C.) at which the spacer particle dispersion is discharged by an inkjet apparatus using a vacuum dryer and dried to 4 g, thereby remaining in the latter stage of drying. A solvent mixture corresponding to the solvent mixture was obtained.

(Evaluation of dispersibility)
The spacer particles are added to the solvent mixture used in the spacer particle dispersion or the solvent mixture remaining in the latter stage of drying so as to be 0.1 wt%, and stirred for 5 minutes or more while being irradiated with ultrasonic waves. Thereafter, the degree of dispersion of the spacer particles was visually observed with a microscope at a magnification of 400 and classified according to the following criteria.
◎: Less than 1 aggregate of 2 balls or more in 1 field of view ○: 2 to 5 aggregates of 2 or more balls in 1 field of view △: Mostly 1 ball in 1 field of view, but 3 or more balls Aggregation of 5 or more x: Mostly 2 balls or more in the field of view

(Evaluation of contact angle)
The obtained spacer particles were stirred and dispersed for 5 minutes or more while irradiating methyl ethyl ketone with ultrasonic waves so that the concentration was 5 wt%, and the obtained spacer particles were dispersed in an aluminum cup with a basis weight of 100 after drying in an aluminum cup. An amount of about (g / m ² ) was added and dried. After drying, the peripheral part of the aluminum cup is removed, and the solvent mixture used in the spacer particle dispersion or the solvent mixture remaining in the latter stage of drying is dropped on the surface on which the spacer particles are spread all over, and the contact angle meter The contact angle was measured. For the contact angle measurement, a contact angle after 0.2 seconds from dropping was measured using a dynamic contact angle measuring device FTA125 manufactured by FTA.

(Preparation of spacer particle dispersion)
The spacer particles obtained by the above-mentioned method are taken in a necessary amount so as to have a predetermined particle concentration, slowly added to a solvent having the composition described in Table 4 below, and dispersed by sufficiently stirring while irradiating ultrasonic waves. It was. Thereafter, the mixture was filtered through a stainless mesh having an opening of 10 μm to remove aggregates, and spacer particle dispersions according to Examples 1 to 10 and Comparative Examples 1 to 8 were obtained.

The surface tension at 20 ° C. of the obtained spacer particle dispersion was measured by the Wilhelmy method using a platinum plate.
In addition, after introducing the spacer particle dispersion liquid to a height of 10 cm into a test tube having an inner diameter of 5 mm, when standing, the time until the spacer particle deposition is visually confirmed on the bottom of the test tube is measured. The sedimentation rate of the particle dispersion was evaluated. The measurement results of surface tension, viscosity, specific gravity, and sedimentation speed are shown in Tables 2 and 3 below.

In addition, the zeta potential of the spacer particles in the spacer particle dispersion and the zeta potential in the latter stage of drying (when reduced by 20% by weight) in the process of drying the spacer particle dispersion are measured as follows, and the measurement results are The results are shown in Tables 2 and 3 below.
The zeta electrometer was measured by diluting to about 0.1 wt% using a zeta electrometer manufactured by Nippon Luft. Regarding the zeta potential in the late drying stage in the process of drying the spacer particle dispersion, 5 g of the spacer particle dispersion having a concentration of about 0.05 wt% is discharged by a vacuum dryer and the spacer particle dispersion is discharged by an inkjet device. The temperature was measured after drying to 4 g at a drying temperature (45 ° C.). In addition, regarding the measurement result, the potential value obtained as the zeta potential is described, but it could not be measured because it could not be measured when there were many aggregates.

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

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

As shown in FIGS. 5A and 5B, a black matrix 23 (width 25 μm, vertical interval 150 μm, horizontal interval 75 μm) made of metallic chromium on a 300 mm × 360 mm glass substrate 22 by a normal method. , Thickness 0.2 μm). On and between the black matrix 23, color filter 24 pixels (thickness 1.5 μm) composed of three colors of red, green and blue were formed so as to have a flat surface. An overcoat layer 25 and an ITO transparent electrode 26 having a substantially constant thickness were provided thereon.
Further thereon, a polyimide resin solution was applied by spin coating. After coating, the film was dried at 150 ° C., then baked at 230 ° C. for 1 hour, and cured to form an alignment film 27 having a substantially constant thickness. At this time, in order to form any of the alignment films of PI1, PI2, and PI3, any one of the following three different polyimide resin solutions was used. The surface tension (γ) of the formed alignment film was as follows.

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

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

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

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

(Spacer particle arrangement by inkjet method)
In this example and comparative example, spacer particles were arranged by the following method using the spacer particle dispersion shown in Table 4, the color filter substrate 21, and the TFT array model substrate 31. When arranging the spacer particles, the arrangement is started after discarding 0.5 mL of the initial spacer particle dispersion discharged from the nozzle of the ink jet device, and in Tables 2 and 3, when the color filter substrate is used Indicated as “21” and expressed as “31” when a TFT array model substrate is used.

First, the color filter substrate 21 having the steps shown in FIG. 5 was placed on the stage. On this color filter substrate 21, using the above-described ink jet device, aiming at the black matrix 23 portion, the spacer particles shown in Table 4 are arranged at intervals of 300 μm on every other vertical line on the vertical line. The droplets of the dispersion were ejected at a pitch of 300 μm in length and 150 μm in width, arranged, and then dried on a hot plate heated to 45 ° C. The distance between the nozzle (head surface) and the substrate during ejection was 0.5 mm, and a double pulse method was used.

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

A TFT array model substrate 31 having a step 33 shown in FIG. 6 was placed on the stage. On this substrate, using the above-described ink jet device, aiming at the step 33 corresponding to the black matrix 23, the spacers shown in Table 4 are arranged at intervals of 300 μm on every other vertical line and on the vertical line. The droplets of the particle dispersion were discharged at a pitch of 300 μm in length and 150 μm in width, arranged, and then dried on a hot plate heated to 45 ° C. The distance between the nozzle (head surface) and the substrate during ejection was 0.5 mm, and a double pulse method was used.

After ejection, the initial contact angle (θ) and receding contact angle (θr) of the droplets of the spacer particle dispersion with respect to the substrate were measured with a contact angle meter. The results are shown in Tables 2 and 3.
In order to investigate the initial contact angle (θ) and receding contact angle (θr) of the droplets of the spacer particle dispersion after discharge to the substrate, the same substrate was separately used. After dropping the liquid droplets, the contact angles were measured with a general contact angle meter of a system that obtains the contact angle by observing with a magnifier camera from the side. Here, the receding contact angle is smaller than the initial landing diameter when the spacer particle dispersion droplet placed on the substrate is placed on the substrate and dried. It is a measurement of the contact angle when it starts to form (when the droplet starts to shrink).
In Tables 2 and 3, “<5” means that the droplet did not spread out but was below the measurement limit of the contact angle meter, and “0.0” It means that wetting and spreading and contact angle could not be measured.

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

(Evaluation)
The following items were evaluated. The results are shown in Tables 2 and 3.

(Drying time)
The time t (minutes) required for the solvent of the droplets formed by discharging the spacer particle dispersion on the surface of the substrate to be discharged shown in Table 4 was measured visually (microscope).

(State of spacer particles when drying droplets)
The droplets formed by discharging the spacer particle dispersion liquid onto the surface of the substrate to be discharged shown in Table 4 were dried, the state of the spacer particles accompanying the weight reduction was observed, and the determination was made according to the following criteria.
○: Almost all spacer particles were aggregated.
Δ: Some spacer particles were not aggregated.
X: Many spacer particles were dispersed.

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

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

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

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

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

In addition, Tables 2 and 3 below show boiling points, viscosities, and surface tensions of the solvents used in Examples and Comparative Examples.

As shown in Table 2, the dispersion of the spacer particles according to the example all deteriorated in the dispersibility of the spacer particles with respect to the solvent, and the drying time was 1.5 minutes or less. Moreover, the difference with respect to SP value of the spacer particle | grain surface of the spacer particle | grain dispersion liquid which concerns on Examples 1-6, 9 and 10 becomes large as it dries, and spacer particle | grain dispersion | distribution which concerns on Examples 6-8 is further increased. The solution had a lower zeta potential as it dried. In addition, although the spacer particle dispersions according to Examples 7 and 8 have a small contact angle difference with respect to the substrate surface before and after drying, the difference in SP value with respect to the SP value of the spacer particle surface increases as it dries. The potential also decreased as it dried. The spacer particle dispersions according to Examples 3 to 5 can obtain the same effect even when the substrate to be discharged is changed from the TFT model substrate to the color filter model substrate or when the alignment film is changed. It was.
On the other hand, as shown in Table 3, the spacer particle dispersion according to Comparative Example 1 has a larger initial SP value difference than the spacer particle dispersions according to Examples 7 to 10 (in Examples 1 to 6). The spacer particle dispersion is also large, but the zeta potential was higher and more stable than the spacer particle dispersion according to Comparative Example 1), and since the zeta potential is also low, the initial dispersibility is not good and drying is possible. It took a long time. Although the spacer particle dispersion according to Comparative Example 2 had a short drying time, the SP value difference (A) with respect to the SP value on the surface of the spacer particles was small, and the SP value with respect to the SP value on the surface of the spacer particles as it dried ( B) and the contact angle difference were small and the dispersibility was good. Further, since the receding contact angle is not high, the spacer particles do not gather in the droplets and the droplets do not shrink, and therefore the spacer particles do not gather at all. Since the spacer particle dispersions according to Comparative Examples 3 to 7 used a high boiling point solvent, drying took a long time. Although the spacer particle dispersion liquid according to Comparative Example 8 has a short drying time, the initial contact angle with respect to the substrate to be ejected was less than 5 degrees. Therefore, immediately after being ejected, before the spacer particles gathered together, The droplets spread and most of the spacer particles were exposed and did not gather together.

According to the present invention, a spacer particle dispersion liquid crystal capable of quickly and selectively disposing spacer particles at a specific position corresponding to a non-pixel region on a substrate using an ink jet device, a liquid crystal A method for manufacturing a display device and a liquid crystal display device can be provided.

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

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 1 '... Spacer particle 2 ... Meniscus 3 ... Spacer particle dispersion 5, 5' ... Droplet 11 ... Spacer particle 21 ... Color filter substrate 22 ... Crow substrate 23 ... Black matrix 24 ... Color filter 25 ... Overcoat layer 26 ... Transparent electrode 27 ... Alignment film 31 ... TFT array model substrate 32 ... Glass substrate 33 ... Step 34 ... Transparent electrode 35 ... Transparent electrodes 40 and 40 '... Droplets 41 and 41' ... Spacer particles 100 ... Head 101 ... Ink chamber 1 (Common ink chamber)
102: Ink chamber 2 (pressure ink chamber)
103 ... discharge surface (nozzle surface)
104 ... Nozzle hole 105 ... Temperature control means 106 ... Piezo element

Claims (9)

A spacer particle dispersion containing spacer particles and a solvent, and used when arranging the spacer particles on the surface of the substrate using an inkjet device,
In the step of drying the droplet formed by discharging on the surface of the substrate, the spacer particles aggregate inside the droplet before the droplet is completely dried,
A spacer particle dispersion, wherein the solvent has a boiling point of 50 to 190 ° C. The spacer particle dispersion according to claim 1, wherein an initial contact angle (θ) of the droplet formed by discharging on the surface of the substrate with respect to the substrate is 5 degrees or more. 2. In the step of drying droplets formed by discharging onto the surface of a substrate, spacer particles inside the droplets aggregate when the weight of the droplets is reduced by 5% by weight or more. Alternatively, the spacer particle dispersion according to 2. The difference (A) between the solubility parameter (SP value) of the solvent and the solubility parameter (SP value) of the spacer particle surface satisfies the following formula (1), and
The difference (B) between the solubility parameter (SP value) of the solvent and the solubility parameter (SP value) of the spacer particle surface when the weight of the droplet formed by discharging on the surface of the substrate is reduced by 5% by weight or more is expressed by the following formula: The spacer particle dispersion according to claim 1, 2 or 3, wherein (2) is satisfied.
| A | ≦ 5 (1)
| B | ≧ | A | +0.2 (2) 5. The spacer particle dispersion according to claim 1, wherein the spacer particle surface has a solubility parameter (SP value) δ of 9.50 or more. The contact angle (θs1) of the solvent with respect to the spacer particles in the droplet immediately after being discharged and formed on the surface of the substrate, and the contact angle (θs2) of the solvent with respect to the spacer particles when the weight of the droplet is reduced by 5% by weight or more 6) The spacer particle dispersion according to claim 1, wherein the difference (θs2−θs1) with respect to (1) is 1 degree or more. When the spacer particles have a carboxyl group on the surface and the weight of the droplets formed by discharging onto the substrate surface is reduced by 5% by weight or more, 10% by weight of water and a solvent having a boiling point of 190 ° C. or less are used as the solvent. The spacer particle dispersion according to claim 1, 2, 3, 4, 5 or 6. A method of manufacturing a liquid crystal display device having a pixel region and a non-pixel region,
By ejecting the spacer particle dispersion liquid onto the surface of the first substrate or the second substrate using an ink jet device, the droplets of the spacer particle dispersion liquid are arranged at specific positions corresponding to the non-pixel regions. Step 1,
Aggregating spacer particles in the droplets of the spacer particle dispersion, and
A method of manufacturing a liquid crystal display device, comprising: a step 3 of overlapping the first substrate and the second substrate so as to face each other through liquid crystal and the agglomerated spacer particles. A liquid crystal display device comprising the spacer particle dispersion according to claim 1, or the method for producing a liquid crystal display device according to claim 8.

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