JP3453381B2 - Adhesive spacer for liquid crystal display panel, its manufacturing method and liquid crystal display panel - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an adhesive spacer for a liquid crystal display panel in which impurities are unlikely to be mixed into liquid crystal, a method for manufacturing the same, and a liquid crystal display panel.

[0002]

2. Description of the Related Art A liquid crystal display (LCD) is widely used as an image display device for televisions, personal computers, word processors, PHSs (personal digital assistants), car navigation systems and the like. Among the liquid crystal display panels, the liquid crystal display panel called TFT-LCD is capable of responding to high-speed response and widening the viewing angle.
The development of a large-screen TFT-LCD with a size of 13 inches or more is being studied with the aim of replacing it with RT). Large screen T
When manufacturing an FT-LCD, in the manufacturing process of the liquid crystal panel, when the substrate is transported, the substrate is cut, or the liquid crystal panel is transported, vibration or shock is applied, and the spacer inside the liquid crystal panel moves, and as shown in and below. However, there is a problem of deterioration in display quality of the liquid crystal panel.

Disturbance of liquid crystal alignment and damage of the alignment film occur, light leakage increases, and contrast decreases. Gap unevenness and color unevenness occur. Therefore, for the purpose of preventing the spacer from moving or falling off,
An adhesive spacer in which an adhesive is coated on the surface of spacer particles has been developed. The adhesive spacer is adhered and fixed to the substrate by being dry-sprayed or wet-sprayed on the substrate and heated (usually at a temperature of 140 to 160 ° C. to melt the sealing resin). From the viewpoint that the adhesive spacer can be easily produced, a method of coating the surface of the raw material particles with a thermoplastic resin using an impact force has been performed (Japanese Patent Laid-Open No. 63-94224, Japanese Patent Laid-Open No. 94224/1988). -15
4028, JP-A-8-328022 and JP-A-9-235527). In the production of the adhesive spacer, a method of grafting the surface of the raw material particles with a polymer chain using a thermoplastic resin is also carried out (JP-A-5-188384, JP-A-5-232480 and JP-A-5-232480). 7-300866, JP-A-7-300
587, JP-A-7-301810, JP-A-7-333623, JP-A-8-43834, JP-A-8-48979, and JP-A-8-3280.
18, Japanese Unexamined Patent Publication No. 9-244034, Japanese Unexamined Patent Publication No.
-194842).

By the way, a liquid crystal display panel is required to have a high voltage holding ratio and excellent driving stability and liquid crystal alignment characteristics. These properties are often affected by the goodness of the spacer. However, conventional spacers are still unsatisfactory in these respects.

[0005]

Therefore, the problem to be solved by the present invention is to provide a liquid crystal display panel having a high voltage holding ratio and excellent driving stability and liquid crystal alignment characteristics, and an adhesive spacer for obtaining the same. And to provide a manufacturing method thereof.

[0006]

In order to solve the above-mentioned problems, the present inventor first investigated the cause of the deterioration of the electrical properties and alignment properties of liquid crystals in the conventional adhesive spacer, and the cause was the adhesive property. It was found that there is an impurity generated in manufacturing the spacer. Although the thermoplastic resin used for the adhesive spacer has a small amount, impurities such as low molecular weight polymers, oligomers, and monomers are present, and these are transferred to the adhesive spacer when the thermoplastic resin is attached to the raw material particles. Polymers that could not be attached to the surface of the raw material particles due to grafting or the like may also become impurities. Further, when the raw material particles are coated with the thermoplastic resin by using the impact force to form the adhesive layer, impurities such as low molecular weight polymers, oligomers and monomers are generated. Although impurities remain in the adhesive spacer due to such a cause, it is common to both the grafting method and the impact force utilizing method, but the impact method is used to attach the thermoplastic resin to the raw material particles. In this case, the impact energy may cause decomposition or depolymerization of the thermoplastic resin, and a large amount of the above impurities may be by-produced. These impurities remain even if the spacer is washed, and it is difficult to completely remove them. Therefore, impurities are easily eluted in the liquid crystal,
The eluted impurities cause deterioration of the electrical characteristics of the liquid crystal (such as a decrease in the voltage holding ratio) and deterioration of the alignment characteristics (a decrease of the pretilt angle), which deteriorates the reliability of the liquid crystal display panel.

Next, as a result of various studies on solutions to this problem, it was conceived that the electrostatic attraction of the particle body and the thermoplastic resin should be positively utilized. That is, it was thought that if the adhesive spacer exerts an electrostatic attractive force, the electrostatic attractive force may attract the impurities to the surface of the raw material particles and suppress the elution of impurities into the liquid crystal. Therefore, as a result of detailed examination of the physical properties and chemical properties of the particle body and the thermoplastic resin, as a means of imparting an electrostatic attractive force to the adhesive spacer, the absolute value of the blow-off charge amount of the particle body and the thermoplastic resin is different. The present invention has been completed by confirming by experiments that these solutions are effective, focusing on the fact that

Therefore, the adhesive spacer for a liquid crystal display panel according to the present invention is an adhesive spacer in which a thermoplastic resin is adhered to at least a part of the surface of the particle body, and the particle body is an organic inorganic material surface-treated. it is made of a composite particle, Bro of the surface-treated particle body and the thermoplastic resin - and wherein the absolute value of the difference between the off charge amount is 100 .mu.C / g or more. The method for producing an adhesive spacer according to the present invention is a method for producing an adhesive spacer in which a thermoplastic resin is attached to at least a part of the surface of raw material particles to be a particle body, in order to produce the adhesive spacer, The particle main body is composed of surface-treated organic-inorganic composite particles, wherein the surface treatment conditions of the raw material particles and the thermoplasticity are set.
Depending on the selection of resin, the raw material particles and
A combination of a thermoplastic resin, by, and performing the deposition of the thermoplastic resin and the raw material particles may grant an impact force to a mixture comprising a powder of the thermoplastic resin.

In the liquid crystal display panel according to the present invention, the adhesive spacer is used as a spacer interposed between the electrode substrates.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION <Adhesive Spacer for Liquid Crystal Display Board> The adhesive spacer according to the present invention is an adhesive spacer obtained by adhering a thermoplastic resin to at least a part of the surface of the particle body. The adhesion here may be that the thermoplastic resin simply coats at least a part of the surface of the particle body, and the thermoplastic resin is grafted on at least a part of the surface of the particle body to chemically bond with the surface of the particle body. It may be in the state of being bound by, or both the coating and the chemical bond may be present.

The adhesive spacer of the present invention can be used by either a wet or dry spraying method. However, since the adhesive spacer can be uniformly sprayed without aggregation of the adhesive spacer, a dry spraying method can be used. Especially suitable for. [Raw Material Particles as Particle Main Body] The raw material particles as the particle main body keep the thickness of the liquid crystal layer uniform and constant when used in a liquid crystal display panel. The average particle size of the raw material particles is preferably 1 to 30 μm, more preferably 1 to 20 μm.
μm, most preferably 1 to 15 μm. If the average particle diameter is out of the above range, it may not be used as an adhesive spacer.

The coefficient of variation (CV) of the particle size of the raw material particles is
It is preferably 10% or less, more preferably 8% or less, still more preferably 6% or less. Coefficient of variation of particle size is 10
If it exceeds%, it becomes difficult to keep the thickness of the liquid crystal layer uniform and constant, and image unevenness is likely to occur. The shape of the raw material particles may be any particle shape such as spherical, needle-shaped, plate-shaped, scale-shaped, crushed, bale-shaped, cocoon-shaped, and sugar-shaped sugar, and is not particularly limited, but the gap distance of the liquid crystal display plate is uniform. A spherical shape is preferable for maintaining a constant value. This is because if the particles are spherical, they can have a constant or nearly constant particle size in all or almost all directions.

There are various kinds of raw material particles, and they are not particularly limited. For example, organic crosslinked polymer particles,
Examples include organic-inorganic composite particles. Among these, vinyl-based cross-linked polymer particles and organic-inorganic composite particles are preferable in terms of preventing damage to the electrode substrate, the alignment film or the color filter and making it easy to obtain a uniform gap distance between both electrode substrates. Body particles are most preferred.
The organic crosslinked polymer particles are not particularly limited, but for example, divinylbenzene crosslinked resin particles obtained by polymerizing divinylbenzene alone or copolymerizing with other vinyl monomers (JP-A-1-14429). See) and the like.

The organic-inorganic composite particles are composite particles composed of an organic part and an inorganic part. In the organic-inorganic composite particles, the ratio of the inorganic portion is
Although not particularly limited, for example, with respect to the weight of the organic-inorganic composite particles, in terms of inorganic oxide, preferably 10 to 90 wt%, more preferably 25 to 85 wt%.
%, More preferably 30 to 80 wt%. Inorganic oxide conversion indicating the proportion of the inorganic portion is expressed as a weight percentage obtained by measuring the weight before and after firing the organic-inorganic composite particles at a high temperature (for example, 1000 ° C.) in an oxidizing atmosphere such as air. Be done. If the proportion of the inorganic portion of the organic-inorganic composite particles is less than the above range in terms of inorganic oxide, the organic-inorganic composite particles become soft, and the number of particles dispersed on the electrode substrate may increase, and
If the amount exceeds the above range, the film may be too hard and the alignment film may be damaged or the TFT may be broken.

The organic / inorganic composite particles are not particularly limited, but include, for example, an organic polymer skeleton and an organic silicon in which a silicon atom is directly chemically bonded to at least one carbon atom in the organic polymer skeleton. Examples thereof include organic-inorganic composite particles containing a polysiloxane skeleton in the molecule and having an amount of SiO2 constituting the polysiloxane skeleton of 10 wt% or more. As the organic polymer skeleton, a vinyl-based polymer is preferable because it gives high resilience capable of controlling the gap control. The organic-inorganic composite particles may be colored by containing a dye and / or a pigment.

The method for producing the organic-inorganic composite particles is not particularly limited, and examples thereof include the following production methods including a condensation step, a polymerization step and a heat treatment step.
The condensation step is a step of hydrolyzing and condensing with a radically polymerizable group-containing silicon compound. The radically polymerizable group-containing silicon compound has the following general formula (1):

[0017]

[Chemical 1]

(Wherein Ra represents a hydrogen atom or a methyl group; Rb represents 1 to 1 carbon atoms which may have a substituent).
20 represents a divalent organic group; Rc represents at least one monovalent group selected from the group consisting of a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, and an acyl group having 2 to 5 carbon atoms. )
And the following general formula (2):

[0019]

[Chemical 2]

(Wherein Rd represents a hydrogen atom or a methyl group; Re is at least selected from the group consisting of a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, and an acyl group having 2 to 5 carbon atoms. One monovalent group) and the following general formula (3):

[0021]

[Chemical 3]

(Here, Rf represents a hydrogen atom or a methyl group; Rg represents a carbon atom which may have a substituent.
20 represents a divalent organic group; Rh represents at least one monovalent group selected from the group consisting of a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, and an acyl group having 2 to 5 carbon atoms. )
It is a compound represented by at least one general formula selected from the group consisting of or and a derivative thereof. The polymerization step is a step in which a radical-polymerizable group is subjected to a radical polymerization reaction during and / or after the condensation step to obtain particles.

The heat treatment step is a step of drying and firing the polymer particles produced in the polymerization step at a temperature of 800 ° C. or lower. The heat treatment step is performed, for example, in an atmosphere having an oxygen concentration of 10% by volume or less. A coloring step of coloring the produced particles may be further included during and / or after at least one step selected from the condensation step, the polymerization step and the heat treatment step. The raw material particles may be colored by including at least one selected from the group consisting of dyes and pigments. The color is preferably a color that does not allow light to easily pass through or a color that does not allow light to pass through because the adhesive spacer itself can prevent light leakage and the contrast of image quality can be improved. Colors that are difficult to transmit light or do not transmit are, for example, black, dark blue, navy blue, purple, blue, dark green,
Colors such as green, brown and red can be mentioned, but particularly preferably,
Black, dark blue, and dark blue.

The dye and / or pigment may be simply contained in the raw material particles, or may have a structure in which the dye and / or pigment and the matrix constituting the particle main body are bound by a chemical bond. . The adhesive spacer has a difference in absolute value of blow-off charge amount between the particle body and the thermoplastic resin. The blow-off charge amount of the particle body can also be adjusted by subjecting the raw material particles to be the particle body to a surface treatment.
The method of such surface treatment is not particularly limited, and the surface treatment using an organic aluminum compound such as aluminum oxide or an aluminum chelate compound for the core particles serving as the core of the raw material particles; Amino group surface treatment using a contained silane coupling agent; phenyl group surface treatment using a phenyl group-containing silane coupling agent such as phenyltrimethoxysilane. As the surface treatment method, the surface treatment method described below for the raw material particles used for the second adhesive spacer can also be adopted. As the core particles, those mentioned above as the raw material particles are used as they are.

As the raw material particles of the adhesive spacer, those having an amino group on the surface can be used. Examples thereof include crosslinked polymer particles having an amino group on the surface and organic-inorganic composite particles having an amino group on the surface. Among these, cross-linked polymer particles having an amino group on the surface and organic-inorganic composite particles are preferable in terms of preventing damage to the electrode substrate, the alignment film or the color filter, and easily obtaining a uniform gap distance between both electrode substrates. . As the crosslinked polymer particles having an amino group on the surface, vinyl-based crosslinked polymer particles having an amino group on the surface are particularly preferable. The raw material particles having an amino group on the surface are, for example, a method of reacting core particles such as organic cross-linked polymer particles and organic-inorganic composite particles with an amino group-containing surface treatment agent (surface treatment method, which will be described later in detail); A method of granulating a raw material containing one kind of amino group-containing compound, for example, a copolymerization reaction using an amino group-containing monomer to give crosslinked polymer particles or organic / inorganic composite particles having an amino group on the surface thereof. It is manufactured by a manufacturing method (an amino group-containing monomer copolymerization method, which will be described later in detail) or the like.

The amount of blow-off charge of the above-mentioned raw material particles is generally about +2000 to -2000 µC / g, preferably about +1500 to -1800 µC / g, and most preferably about +50 to -1500 µC / g. Below, the above-mentioned surface treatment method and amino group-containing monomer copolymerization method for introducing an amino group into the surface of the raw material particles will be described in detail. <Surface treatment method> This is a method of introducing amino groups to the surface of raw material particles by reacting core particles such as crosslinked polymer particles and organic-inorganic composite particles with an amino group-containing surface treatment agent.

The amino group-containing surface treatment agent used in the surface treatment method is not particularly limited as long as it is an amino group-containing alkoxysilane compound. For example, N-β (aminoethyl) γ-aminopropyltrimethoxysilane. ,
N-β (aminoethyl) γ-aminopropylmethyldimethoxysilane, γ-aminopropyltrimethoxysilane, N-phenyl-γ-aminopropyltrimethoxysilane, N-benzyl-γ-aminopropyltrimethoxysilane, N-methyl -Γ-aminopropyltrimethoxysilane, N, N-dimethyl-γ-aminopropyltrimethoxysilane, and a triethoxysilane compound in which the methoxy group of these silane compounds is substituted with an ethoxy group,
An amino group-containing silane coupling agent such as a methyldiethoxysilane compound may be used, and one or more of these are used.

As a method for reacting the core particles and the amino group-containing surface treating agent, a conventionally known method is adopted, and there is no particular limitation, and the following method can be exemplified. After the core particles are immersed in the treatment liquid containing the amino group-containing surface treatment agent, they are dried as they are or after filtration. A treatment liquid containing an amino group-containing surface treatment agent is sprayed or applied on the core particles and dried. The amino group-containing surface treatment agent is vaporized and the gas is brought into contact with the core particles.

The amount of the amino group-containing surface treating agent used is not particularly limited, but is preferably 0.1 to 500% by weight, more preferably 0.5% by weight based on the weight of the core particles.
-100% by weight, most preferably 1-50% by weight. Within the range, the surface treatment effect is high, but outside the range, the surface treatment effect may be lowered. The drying temperature and the drying time are not particularly limited. The drying temperature is preferably 40 to 250 ° C, more preferably 60 to 200 ° C. The drying time is preferably 10 minutes to 12 hours, more preferably 30 minutes to 5 hours. If the drying temperature or the drying time deviates from the above range, the surface treatment effect may decrease.

<Amino group-containing monomer copolymerization method>
It is a method of copolymerizing using an amino group-containing monomer. As the amino group-containing monomer used for producing the crosslinked polymer particles having an amino group on the surface, for example,
Examples thereof include amino group-containing vinyl-based monomers such as N, N-dimethyl-aminoethyl (meth) acrylate and N, N-dimethyl-aminopropyl (meth) acrylate. These are used alone or in combination of two or more. It A crosslinked polymer particle having an amino group on the surface is produced by copolymerizing these amino group-containing monomers with, for example, a (meth) acrylic acid ester or a vinyl-based monomer such as styrene or divinylbenzene. .

The amino group-containing monomer used for producing the organic / inorganic composite particles having an amino group on the surface includes, for example, the amino group-containing surface treatment agent used in the above-mentioned surface treatment method. Yes, these are 1
One kind or two or more kinds are used. This amino group-containing surface treatment agent or the like can be prepared, for example, from the above general formulas (1), (2) or
By using the silicon compound represented by the formula (3) together with the method described above as a method for producing organic-inorganic composite particles, organic-inorganic composite particles having an amino group on the surface are produced. [Thermoplastic resin] The thermoplastic resin is
It adheres to at least a part of the surface of the raw material particles to be the particle main body, that is, a part or the whole of the surface to form an adhesive layer of a thermoplastic resin on the surface of the particle main body. This adhesive layer may simply cover the particle body, may be chemically bonded to the surface of the particle body, or both the coating and the chemical bond may be present. This adhesive layer acts as an adhesive between the raw material particles and the electrode substrate.

Examples of the thermoplastic resin include resins containing homopolymers or copolymers of ethylenically unsaturated monomers. Examples of the ethylenically unsaturated monomer include ethylene, propylene, vinyl chloride, vinyl acetate, styrene, vinyltoluene, α-methylstyrene, (meth) acrylic acid ester (for example, methyl (meth) acrylate, ethyl (meth)). Acrylate,
n-propyl (meth) acrylate, isopropyl (meth) acrylate, butyl (meth) acrylate, hexyl (meth) acrylate, lauryl (meth) acrylate, cyclohexyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, glycidyl (meth)
Acrylate, trifluoropropyl (meth) acrylate, etc.) and the like.

Among the above ethylenically unsaturated monomers,
If the ethylenically unsaturated monomer contains an aromatic residue (for example, a phenyl group) or a hydrogen-bondable residue (such as an ester group), the intermolecular force with the alignment film increases, This is preferable because the adhesive force to the substrate also increases. It is particularly preferable that the ethylenically unsaturated monomer is (meth) acrylic acid ester or styrene, since the charge retention rate after 5 minutes of corona charging becomes higher. In this sense,
The thermoplastic resin is a (meth) acrylic resin having (meth) acrylate as an essential component as a monomer unit, a styrene resin having a styrene compound as an essential component as a monomer unit, and styrene as a monomer unit. It is preferably at least one selected from the group consisting of (meth) acryl-styrene resins containing a compound and (meth) acrylate as essential components.

As the (meth) acrylic resin, 45 wt% or more of (meth) acrylate having an alkyl group having 6 or more carbon atoms as a monomer unit (preferably, from the viewpoint of suppressing light leakage near the spacer) is preferable. A (meth) acrylic resin containing 50 wt% or more, more preferably 60 wt% or more) is preferable. When polymerizing a (meth) acrylic acid ester or styrene to produce a thermoplastic resin, soap-free polymerization is particularly preferable. Soap-free polymerization reduces the amount of conductive impurities such as surfactants, increases the molecular weight of the polymer, and reduces the elution of impurities into the liquid crystal, improving the reliability of the liquid crystal display panel and maintaining the voltage. This is because the rate tends to increase.

The thermoplastic resin is not limited to the above. For example, polyesters such as polyethylene terephthalate and polybutylene terephthalate; various polyamides; various polycarbonates; various epoxy resins can be used as the thermoplastic resin. As the thermoplastic resin, one kind or two or more kinds of those listed above are used. The glass transition temperature of the thermoplastic resin is preferably 130 ° C or lower, more preferably 120 ° C or lower. The melting temperature of the thermoplastic resin is preferably 180 ° C or lower, more preferably 150 ° C or lower. The thermoplastics mentioned above generally have
10 to -2000 μC / g or so, preferably -50 to-
1800 μC / g, most preferably -100 to -1
It has a blow-off charge amount of about 500 μC / g and a charge retention rate of 40% or more after 5 minutes of corona charging.

The thermoplastic resin may be colored by containing at least one selected from the group consisting of dyes and pigments. Examples of the preferable color include the colors described above as the preferable color of the raw material particles for the spacer. The dyes and pigments that can be used for coloring the thermoplastic resin are not particularly limited, and examples thereof include those described above as the dyes and pigments that can be used for coloring the raw material particles of the spacer. The weight ratio of the thermoplastic resin is
Although not particularly limited, it is preferably more than 0% and 30% or less, more preferably 0.1 to 25, relative to the particle body.
%, Most preferably 0.5 to 20%. When the weight ratio of the thermoplastic resin exceeds 30%, the image quality of the liquid crystal display panel may be deteriorated. On the other hand, if the weight ratio of the thermoplastic resin is low, the adhesiveness will decrease.

The thickness of the thermoplastic resin adhered to at least a part of the surface of the particle body is not particularly limited, but it is essential that it is smaller than the radius of the particle body, and preferably 1/2 or less of the radius of the particle body. Yes, preferably 0.001
1 μm range, more preferably 0.01 to 0.5 μm
Is the range. If the thickness is smaller than the above range, the adhesiveness may be deteriorated, and if the thickness is larger than the above range, the area covering the alignment film, the color filter or the like becomes large, and the display quality of the liquid crystal display plate is deteriorated. There is a fear. [Meaning of Physical and Chemical Properties in Spacer] As described above, in the adhesive spacer according to the present invention, the absolute value of the difference in blow-off charge amount between the particle body and the thermoplastic resin is 1
It is not less than 00 μC / g, and due to this electrostatic attraction, impurities derived from the thermoplastic resin (low molecular weight polymer, oligomer, monomer, etc.) are attracted to the surface of the particle main body, and elution into the liquid crystal is suppressed.

As described above, in the adhesive spacer according to the present invention, the raw material particles having the amino group on the surface are used as the raw material particles forming the main body of the particles, whereby the raw material particles are likely to be positively charged. . On the other hand, the thermoplastic resin tends to be negatively charged. Therefore, the impurities are attracted to the surface of the particle main body by electrostatic attraction, and the elution into the liquid crystal is suppressed. In the adhesive spacer according to the present invention, as described above, the electrostatic attraction works between the particle body and the thermoplastic resin, so that the adhesiveness between the particle body and the adhesive layer made of the thermoplastic resin adhered to the particle body The spacer will not move easily even when subjected to strong vibration or shock.

As described above, in the adhesive spacer, the absolute value of the difference in the blow-off charge amount between the particle body and the thermoplastic resin is important. That is, the absolute value of the difference between the blow-off charge amounts of the raw material particles to be the particle body and the thermoplastic resin is 100.
μC / g or more is necessary, preferably 15
It is 0 μC / g or more, more preferably 200 μC / g or more, and most preferably 300 μC / g or more. The larger the absolute value of the difference in the amount of blow-off charge, the better because the electrostatic attraction between the particle body and the thermoplastic resin increases in proportion to the magnitude of the absolute value.
When the absolute value of the difference in the amount of blow-off charge is less than 100 μC / g, the electrostatic attraction is weak, and therefore impurities derived from the thermoplastic resin may be eluted in the liquid crystal.

Regarding the blow-off charge amount of the particle body and the thermoplastic resin, the absolute value of the difference in charge amount between the two is 100 μC.
If the blow-off charge amount of the particle body and the thermoplastic resin are both negative values, or if the blow-off charge amount of the particle body is a positive value, the thermoplastic resin The case where the blow-off charge amount of the resin is a negative value is preferable, and the former case is more preferable. If the blow-off charge amount of the particle body and the thermoplastic resin are both positive values, the adsorption to the alignment film is too strong, the alignment film near the spacer is damaged, light leakage increases, and the contrast decreases. May occur. Regarding the blow-off charge amount, the surface treatment of the core particles and the composition of the thermoplastic resin can be selected with reference to, for example, the charging sequence. <Production Method of Adhesive Spacer> The production method of the adhesive spacer according to the present invention is not particularly limited, but the production method of the present invention described below can be mentioned as a preferred method.

In order to manufacture the adhesive spacer, a thermoplastic resin whose absolute value of the difference in blow-off charge amount from the raw material particles is 100 μC / g or more is used. The method for producing the adhesive spacer according to the present invention includes
There are the following two methods which differ in the means of attaching the thermoplastic resin. [Impact Force Utilization Method] This method is characterized by applying an impact force to a mixture containing raw material particles and a powder of a thermoplastic resin to adhere the thermoplastic resin to at least a part of the surface of the raw material particles.

The adhesive spacer according to the present invention can be easily obtained by this method. The raw material particles and the thermoplastic resin used in this method have been described above. The surface of the raw material particles may be surface-treated. The method of surface treatment has also been described above. When coating the particle body surface with the thermoplastic resin powder, the average particle diameter of the thermoplastic resin powder is required to be smaller than the radius of the particle body,
It is 1/2 or less of the radius of the particle body. In particular, if the average particle size exceeds 2 μm, the coating efficiency of the raw material particles may decrease. Therefore, the average particle diameter of the thermoplastic resin powder is preferably 2 μm or less, more preferably 1 μm.
m or less, and most preferably 0.5 μm or less.

The ratio of the thermoplastic resin powder to the raw material particles [(thermoplastic resin powder / particles) × 100] is not particularly limited and is preferably 0.1 to 30 wt%.
More preferably 1 to 25 wt%, most preferably 2 to 2
It is 0 wt%. 30 wt% of thermoplastic resin powder
If it exceeds%, the thickness of the thermoplastic resin coating layer becomes large, and when melted, the area covering the electrode substrate, the alignment film, the color filter, etc. becomes large, and the image quality of the liquid crystal display panel may deteriorate. On the other hand, if the proportion of the thermoplastic resin powder is less than 0.1 wt%, the adhesiveness may be reduced. The method of applying an impact force to the mixture containing the raw material particles and the thermoplastic resin powder is not particularly limited, and examples thereof include a high-speed air current impact method and a ball mill method.

In the high-speed air impact method, for example, raw material particles and a thermoplastic resin powder are mixed, the mixture is dispersed in a gas phase, and mechanical thermal energy mainly having an impact force is applied to the mixture. This is a method in which at least a part of the thermoplastic resin powder is melted and the thermoplastic resin is attached to the surfaces of the raw material particles, and the coating can be performed easily and efficiently. As a device using the high-speed air impact method,
Although not particularly limited, for example, a hybridization system manufactured by Nara Machinery Co., Ltd., a mechanofusion system manufactured by Hosokawa Micron Co., Ltd., a Kryptron system manufactured by Kawasaki Heavy Industries Ltd., and the like can be mentioned. [Grafting Method] This method is characterized in that the surface of the raw material particles is grafted with a thermoplastic resin and the thermoplastic resin is attached to at least a part of the surface of the raw material particles.

The adhesive spacer according to the present invention can be easily obtained by this method. The raw material particles used in this method have functional groups such as epoxy groups, hydroxyl groups, carboxyl groups, mercapto groups, amino groups, haloalkyl groups, silanol groups, alkoxysilyl groups, and isocyanate groups on the surface of the above-described raw material particles. It is a thing.
Only one type of functional group exists on the surface of the raw material particles, and 2
More than one species can coexist. The functional group can be easily introduced by surface-treating the raw material particles. The thermoplastic resin has a reactive group that reacts with the functional group. Examples of the reactive group include an epoxy group, an oxazoline group, an aziridine group, a carboxyl group, an amino group, an isocyanate group, an alkoxysilyl group, a silanol group, a hydroxyl group, and the like. Can coexist.

The ratio of the thermoplastic resin to the raw material particles is the same as in the impact force method. The specific method of grafting the raw material particles with the thermoplastic resin is not particularly limited, but for example, the raw material particles and the thermoplastic resin are mixed without a solvent or in the presence of a solvent, and a functional group on the surface of the raw material particles It is carried out by heating to a temperature at which the reactive groups in the thermoplastic resin react. Separately from this, a monomer having a polymerizable group or a polymerization initiating group to be a thermoplastic resin may be polymerized on the surface of the raw material particles to graft the thermoplastic resin. <Liquid Crystal Display Plate> The liquid crystal display plate according to the present invention includes, for example, a first electrode substrate, a second electrode substrate, a spacer, a sealant, and a liquid crystal, as in the conventional case. The first electrode substrate includes a first substrate and a first electrode formed on the surface of the first substrate.
And an electrode. The second electrode substrate has a second substrate and a second electrode formed on the surface of the second substrate, and faces the first electrode substrate. The spacer is an adhesive spacer for a liquid crystal display panel, and is interposed between the first electrode substrate and the second electrode substrate to maintain a space between the two electrode substrates. This interval is almost the same as the particle size of the spacer. The sealing material bonds the first electrode substrate and the second electrode substrate at the peripheral portion. The liquid crystal is sealed between the first electrode substrate and the second electrode substrate, and is filled in the space surrounded by the first electrode substrate, the second electrode substrate and the sealing material.

The liquid crystal display panel of the present invention is the same as the conventional liquid crystal display panel, but the conventional spacers are replaced by the above-mentioned adhesive spacers of the present invention interposed between the electrode substrates to maintain the distance between the electrode substrates. Is. The LCD panel has
Except for the spacer, such as the electrode substrate, the sealant, and the liquid crystal, the same ones as the conventional one can be used in the same manner. The electrode substrate has a substrate such as a glass substrate or a film substrate, and an electrode formed on the surface of the substrate, and if necessary, an alignment film formed so as to cover the electrode on the surface of the electrode substrate. Have more. An epoxy resin adhesive sealing material or the like is used as the sealing material. As a liquid crystal,
It may be a conventionally used one, for example, biphenyl-based, phenylcyclohexane-based, Schiff base-based, azo-based, azoxy-based, benzoic acid ester-based, terphenyl-based, cyclohexylcarboxylic acid ester-based, biphenylcyclohexane-based, pyrimidine-based Liquid crystals such as dioxane, cyclohexylcyclohexane ester, cyclohexylethane, cyclohexene, and fluorine can be used.

As a method for producing a liquid crystal display panel, for example, an adhesive spacer is used as an in-plane spacer and is uniformly dispersed on one of the two electrode substrates. After being dispersed in an adhesive sealing material such as epoxy resin as a seal spacer,
Place the one coated by means of screen printing or the like on the adhesive seal part of the other electrode substrate, apply an appropriate pressure, and heat the adhesive seal material by heating at a temperature of 140 to 160 ° C. for 1 to 60 minutes. Then, inject the liquid crystal,
A method of sealing the injection portion to obtain a liquid crystal display plate can be mentioned, but the present invention is not limited by the method of manufacturing the liquid crystal display plate. As the in-plane spacer, among the adhesive spacers, the one colored as described above is preferable because the spacer itself hardly causes light leakage.

In producing the liquid crystal display panel, the method of spraying the adhesive spacer may be either a wet method or a dry method. However, in the case of dry spraying, the adhesive spacers are unlikely to aggregate, and the adhesive spacers are uniformly sprayed. It's easy to do. Since the liquid crystal display panel according to the present invention uses the above-mentioned adhesive spacer, the adhesive force to the substrate is strong, the movement of the spacer is reduced, the thickness of the liquid crystal layer is made uniform, and color unevenness occurs. Without it, the display quality is improved. In addition, the elution of impurities (low molecular weight polymer, oligomer, monomer) derived from the thermoplastic resin into the liquid crystal is suppressed, so that the liquid crystal display panel has high reliability. Especially, TFT-L that dislikes invasion of impurities
In a CD, the reliability such as driving stability is enhanced, which is useful. Further, since the adhesiveness is high, the movement of the spacer is prevented, and the display quality such as liquid crystal alignment characteristics is improved. Therefore, it is suitable for use in applications where vibration and impact are likely to occur, such as in-vehicle liquid crystal display panels for car navigation systems and large-sized liquid crystal display panels for monitors of 12 inches or more that require vibration resistance and shock resistance. However, it may be used for the same purpose as that of a conventional liquid crystal display panel, for example, as an image display device for a television, a personal computer, a word processor, a PHS (personal digital assistant), or the like.

[0050]

EXAMPLES Examples and comparative examples of the present invention will be shown below, but the present invention is not limited to the following examples. In the example below,
The average particle diameter and particle diameter variation coefficient of the raw material particles, the blow-off charge amount of the particle body and the thermoplastic resin, the driving stability of the liquid crystal display panel, the voltage holding ratio, and the liquid crystal alignment property are measured by the following methods. <Average particle size and coefficient of variation of particle size> The sample is observed with an electron microscope, the particle size of 200 arbitrary samples of the photographed image is measured, and the average particle size, the standard deviation of the particle size, and The coefficient of variation of particle size was determined.

[0051]

[Equation 1]

[0052]

[Equation 2]

[0053]

[Equation 3]

<Blow-off charge> Iron powder (trade name: DS
P-128, manufactured by Dowa Iron Powder Co., Ltd.) was weighed at 19 (g),
Weigh 1 (g) samples, put them in a glass container,
After mixing lightly, the mixture was vigorously shaken for 10 minutes on a paint shaker to be triboelectrically charged. 0.2 (g) of this mixture
Weigh it, put it in a Faraday cage stretched with stainless steel net (twill weave, 400 mesh), and after 5 minutes, use a blow-off powder charge amount measuring device (MODEL TB-200, manufactured by Toshiba Chemical Co.) to set the nitrogen gas pressure to 1 kg / cm ²
To start blowing off the mixture. The charge amount per 1 g of the sample was calculated from the following formula from the charge amount F (C) of the iron powder remaining on the stainless steel mesh 1 minute after the start of blowing (or after the value reached saturation). , Blow-off charge Q
(C / g).

Q = -F / (0.2 × 1/19) As for the sign (plus or minus) of the value of the blow-off charge amount, the sign opposite to the charge remaining on the stainless steel net is the sign of the sample. . <Driving stability> The liquid crystal display panel is operated at 50 ° C and 100
After driving for 0 hours, the display quality was evaluated. <Voltage holding ratio> A polyimide alignment film was formed on a pair of patterned glass substrates with ITO electrodes, and after rubbing treatment, a liquid crystal cell was produced by bonding so as to have TN alignment. Next, using a liquid crystal voltage holding ratio measuring system, the initial voltage holding ratio was measured at 25 ° C.,
After confirming that the voltage holding ratio is 90% or more, 50 ℃, 50
The voltage holding ratio (measurement temperature: 25 ° C.) after 0 hour was measured. <Liquid Crystal Alignment Characteristic> The light leakage and the feeling of roughness when the liquid crystal display plate was driven were visually observed and evaluated. <Example 1-1> γ-methacryloxypropyltrimethoxysilane and vinyltrimethoxysilane (45/5
(5 weight ratio) was used to perform co-hydrolysis / polycondensation of alkoxysilyl groups and radical polymerization of double bonds to obtain white organic-inorganic composite particles (1-1).

The composite particles (1-1) had an average particle diameter of 5.0 μm, a particle diameter variation coefficient of 3.2%, and a polysiloxane skeleton ratio relative to the weight of the composite particles (1-1). ,
It was 55 wt% as calculated as SiO2 (when fired at 1000 ° C. in air). Next, for the composite particle dispersion (1-1) prepared by dispersing the composite particles (1-1) in toluene-methanol, 2 for the composite particles (1-1).
0% by weight of aluminum acetylacetonate was added and mixed by heating at 65 ° C. After cooling this mixture, toluene and methanol contained in the mixture were distilled off while heating with an evaporator. The obtained residue was vacuum dried at 150 ° C. for 2 hours, washed with toluene and methanol several times, and the residue was filtered, dried and crushed to obtain surface-treated particles (1-1). (Average particle diameter 5.0 μm, coefficient of variation 3.5%).

Next, surface treated particles (1
-1) 35 g and methyl methacrylate / 2-ethylhexyl acrylate (35/65 as a thermoplastic resin
5 g of copolymer (1-1) (weight ratio) was prepared. The blow-off charge amount of the surface-treated particles (1-1) is a negative value, and the blow-off charge amount of the copolymer (1-1) is also a negative value. The absolute value of the difference between these blow-off charge amounts is 329 μm.
It was C / g. After mixing the surface-treated particles (1-1) and the copolymer (1-1), a hybridization system NHS-0 type manufactured by Nara Machinery Co., Ltd. was used,
An adhesive spacer (1-1) was obtained by coating the surface of the surface-treated particles (1-1) with the copolymer (1-1) by an impact method in a high-speed air stream.

A liquid crystal cell (1-1) was prepared by using this adhesive spacer (1-1) as a spacer, and its voltage holding ratio (50 ° C., after 500 hours) was measured and found to be 98%. There was almost no change in the voltage holding ratio. Next, a liquid crystal display plate (1-1), which is a 13-inch TFT liquid crystal display plate, was prepared using the adhesive spacer (1-1), and a predetermined voltage was applied to the liquid crystal display plate (1-
The driving stability of 1) was stable for a long period of time, and the alignment characteristics of the liquid crystal were at a good level. <Examples 1-2 to 1-4> In Example 1-1, the surface-treated particles shown in Table 1 were used in place of aluminum acetylacetonate, and treated in the same manner as in Example 1-1 ( 1-2) to (1-4) were produced. Using the obtained surface-treated particles (1-2) to (1-4) and the thermoplastic resin shown in Table 1, a high-speed air impact method was performed in the same manner as in Example 1-1 to obtain an adhesive spacer ( 1-2) ~
(1-4) was obtained. In Example 1-4, instead of the composite particles (1-1), dark blue particles obtained by dyeing the composite particles (1-1) with methylene blue which is a basic dye were used. In Table 1, the sign of the value of the blow-off charge amount of the surface-treated particles and the thermoplastic resin (plus + or −), and the absolute value of the difference between these blow-off charge amounts are shown.

Obtained adhesive spacers (1-2) to
Using (1-4), in the same manner as in Example 1-1, liquid crystal cells (1-2) to (1-4) and a 13-inch TFT.
Liquid crystal display plates (1-2) to (1-4) which are liquid crystal display plates were produced. In the same manner as in Example 1-1, the voltage holding ratio (5
(0 ° C., after 500 hours) was measured to evaluate the driving stability of the liquid crystal display panel and the alignment characteristics of the liquid crystal. The results are shown in Table 2. Table 2 also shows the results of Example 1-1.

[0060]

[Table 1]

[0061]

[Table 2]

<Examples 1-5 and 1-6> These Examples 1-5 and 1-6 are reference techniques outside the technical scope of the present invention. In Example 1-1, vinyl-based crosslinked polymer particles of divinylbenzene-dipentaerythritol hexaacrylate-N, N-dimethyl-2-aminoethyl methacrylate (60/20/20 weight ratio) were used as raw material particles, Adhesive spacers (1-5) to (1-6) were produced in the same manner as in Example 1-1, except that the plastic resin shown in Table 3 was used. Table 3
Is the sign of the blow-off charge amount of the surface-treated particles and the thermoplastic resin used (plus + or minus-),
The absolute value of the difference between these blow-off charge amounts is shown.

Obtained adhesive spacers (1-5) to
Using (1-6), in the same manner as in Example 1-1, liquid crystal cells (1-5) to (1-6) and 13-inch TFTs.
Liquid crystal display plates (1-5) to (1-6), which are liquid crystal display plates, were produced. In the same manner as in Example 1-1, the voltage holding ratio (5
(0 ° C., after 500 hours) was measured to evaluate the driving stability of the liquid crystal display panel and the alignment characteristics of the liquid crystal. The results are shown in Table 4.

[0064]

[Table 3]

[0065]

[Table 4]

<Example 1-7> A surface-treated particle dispersion liquid was prepared by dispersing the surface-treated particles (1-3) obtained in Example 1-3 in toluene. Next, methyl methacrylate-styrene-2-ethylhexyl acrylate-glycidyl methacrylate (25/3 as a thermoplastic resin)
(0/35/10 weight ratio) of the copolymer (1-7) was prepared in an amount of 1/2 part by weight of the surface-treated particles (1-3), and a copolymer solution was prepared by dissolving the copolymer solution in toluene. The blow-off charge amount of the surface-treated particles (1-3) is a negative value, and the blow-off charge amount of the copolymer (1-7) is also a negative value. The absolute value of the difference between these blow-off charge amounts is 306 μC / It was g. The surface-treated particle dispersion liquid obtained above and the copolymer solution were mixed and stirred at room temperature for 2 hours. After toluene contained in the mixed solution was distilled off by heating using an evaporator, the surface-treated particles (1
Particles obtained by grafting a thermoplastic resin on -3) were obtained. The obtained particles are washed with Soxhlet using toluene,
After filtering, drying and crushing, the adhesive spacer (1-
7) was obtained.

Using the adhesive spacer (1-7) thus obtained, a liquid crystal cell (1-7) was prepared in the same manner as in Example 1-1.
A liquid crystal display plate (1-7) which is a 13-inch TFT liquid crystal display plate was manufactured. The voltage holding ratio (50 ° C., after 500 hours) was measured in the same manner as in Example 1-1 to evaluate the driving stability of the liquid crystal display plate and the alignment characteristics of the liquid crystal. The voltage holding ratio (after 50 hours at 500C) was 95%, which was almost unchanged. When a predetermined voltage was applied to the liquid crystal display plate (1-7), the driving stability of the liquid crystal display plate was stable for a long period of time, and the alignment characteristics of the liquid crystal were at a good level. <Comparative Example 1-1> A comparative surface was prepared in the same manner as in Example 1-1, except that 1% by weight of aluminum acetylacetonate was used with respect to the composite particles (1-1). Treated particles (1-1) were produced.

Next, comparative surface-treated particles (1-1) were used as raw material particles, and methyl methacrylate-2-ethylhexyl acrylate (60/40) was used as a thermoplastic resin.
(Comparative weight ratio) Comparative adhesive spacer (1-) was prepared in the same manner as in Example 1-1, except that the comparative copolymer (1-1) was used.
1) was obtained. The blow-off charge amount of the comparative surface-treated particles (1-1) is a negative value, and the blow-off charge amount of the comparative copolymer (1-1) is also a negative value. The absolute value of the difference between the blow-off charge amounts is It was 78 μC / g. Using the obtained comparative adhesive spacer (1-1), in the same manner as in Example 1-1, the comparative liquid crystal cell (1-1) and the comparative liquid crystal display plate (1) which is a 13-inch TFT liquid crystal display plate (1) were used. -1) was produced. In the same manner as in Example 1-1, the voltage holding ratio (50
(° C, after 500 hours) was measured to evaluate the driving stability of the liquid crystal display panel and the alignment characteristics of the liquid crystal. Voltage holding ratio (50
C., after 500 hours) decreased to 80%. No display was observed even when a predetermined voltage was applied to the comparative liquid crystal display plate (1-1), and a decrease in the alignment characteristics (pretilt angle) of the liquid crystal was observed.

<Comparative Example 1-2> In Example 1-5,
The same crosslinked polymer particles (1-2) of divinylbenzene-dipentaerythritol hexaacrylate-N, N-dimethyl-2-aminoethylmethacrylate as those used in Example 1-5 were used as the raw material particles, Styrene-butyl acrylate-N, N-dimethyl-2-aminoethyl methacrylate (30/40 as a plastic resin
Comparative adhesive spacer (1-2) was obtained in the same manner as in Example 1-5 except that the comparative copolymer (1-2) (/ 30 weight ratio) was used. The comparative crosslinked polymer particles (1-
The blow-off charge amount of 2) is a positive value, and the comparative copolymer (1-
The blow-off charge amount of 2) was also a positive value, and the absolute value of the difference between these blow-off charge amounts was 41 μC / g.

Obtained Comparative Adhesive Spacer (1-2)
In the same manner as in Example 1-1, a comparative liquid crystal cell (1-2) and a comparative liquid crystal display plate (1-2) which is a 13-inch TFT liquid crystal display plate were produced. The voltage holding ratio (50 ° C., after 500 hours) was measured in the same manner as in Example 1-1 to evaluate the driving stability of the liquid crystal display plate and the alignment characteristics of the liquid crystal. Voltage holding ratio (50 ° C, after 500 hours) is 5
It fell to 9%. No display was made even when a predetermined voltage was applied to the comparative liquid crystal display plate (1-2), and deterioration of the alignment characteristics (pretilt angle) of the liquid crystal was observed. <Comparative Example 1-3> In Example 1-3, except that the amount of 3-aminopropyltrimethoxysilane used as the surface treatment agent was changed to 1% by weight based on the composite particles (1-1). Comparative surface-treated particles (1-3), which are raw material particles, were obtained in the same manner as in Example 1-3.

Then, in Example 1-7, the comparative surface-treated particles (1-3) were used instead of the surface-treated particles (1-3).
And methyl methacrylate as a thermoplastic resin
Example 1-7 except that the comparative copolymer (1-3) of styrene-2-ethylhexyl acrylate-glycidyl methacrylate (10/30/50/10 weight ratio) was used.
Comparative adhesive spacer (1-3) was obtained in the same manner as described above. The blow-off charge amount of the comparative surface-treated particles (1-3) is a negative value, and the blow-off charge amount of the comparative copolymer (1-3) is also a negative value. The absolute value of the difference between these blow-off charge amounts is It was 65 μC / g.

The obtained comparative adhesive spacer (1-3)
In the same manner as in Example 1-1, a comparative liquid crystal cell (1-3) and a comparative liquid crystal display plate (1-3) which is a 13-inch TFT liquid crystal display plate were produced. The voltage holding ratio (50 ° C., after 500 hours) was measured in the same manner as in Example 1-1 to evaluate the driving stability of the liquid crystal display plate and the alignment characteristics of the liquid crystal. The voltage holding ratio (50 ° C, after 500 hours) is 7
It fell to 5%. No display was made even when a predetermined voltage was applied to the comparative liquid crystal display plate (1-3), and a decrease in the alignment characteristics (pretilt angle) of the liquid crystal was observed.

[0073]

The adhesive spacer for a liquid crystal display panel according to the present invention can suppress the elution of impurities derived from a thermoplastic resin into the liquid crystal, increase the voltage holding ratio of the liquid crystal display panel, and Improves drive stability and liquid crystal alignment characteristics.
The method for producing an adhesive spacer for a liquid crystal display panel according to the present invention can easily and efficiently obtain the above-mentioned adhesive spacer. In the liquid crystal display panel according to the present invention, since the adhesive spacer is interposed between the electrode substrates,
It has a high voltage holding ratio and is excellent in driving stability and liquid crystal alignment characteristics.

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hironobu Toribuchi 5-8 Nishimitabicho, Suita City, Osaka Prefecture Nihon Shatai Co., Ltd. (72) Inventor Shigefumi Kuramoto 5-8 Nishimitabimachi, Suita City, Osaka Prefecture Nihon Shokubai Co., Ltd. (56) Reference JP-A-9-244032 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G02F 1/1339

Claims (3)

(57) [Claims] 1. A bonding spacer comprising depositing a thermoplastic resin to at least a portion of the particle body surface, said particle body is consisted of an organic and inorganic composite particles treated surface is the surface-treated was Bro the particle body and the thermoplastic resin - the absolute value of the difference between the off charge amount 100μ
An adhesive spacer for a liquid crystal display panel, which is C / g or more. 2. A method for producing an adhesive spacer in which a thermoplastic resin is adhered to at least a part of the surface of raw material particles to be a particle main body, wherein the particle main body comprises surface-treated organic-inorganic composite particles. The raw material grain
For setting the surface treatment conditions of the child and selecting the thermoplastic resin
Therefore, the absolute value of the difference in the amount of blow-off charge is 100 μC /
the raw material particles and the thermoplastic resin so that the amount is g or more.
A method of producing an adhesive spacer for a liquid crystal display panel, characterized in that the thermoplastic resin is adhered by applying an impact force to a mixture containing the raw material particles and the thermoplastic resin powder in combination. . 3. A liquid crystal display panel using the adhesive spacer according to claim 1 as a spacer interposed between electrode substrates.