JPH11202341A - Adhesive spacer for liquid crystal display board, its production and liquid crystal display board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide adhesive spacers which have excellent adhesiveness, hardly allow contamination of impurities into liquid crystals and enhance the reliability of a liquid crystal display board, a process for producing the same and the liquid crystal display board. SOLUTION: The adhesive spacers for the liquid crystal display board are the spacers formed by coating at least part of the surfaces of polymer graft particles formed by grafting a polymer on the surfaces with a thermoplastic resin. This process for production of the adhesive spacer for the liquid crystal display board includes a grafting stage for producing the polymer graft particles by grafting the surfaces of raw material particles with the polymer and a coating stage for coating at least part of the surface of the polymer graft particles with the thermoplastic resin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an adhesive spacer for a liquid crystal display panel, a method for manufacturing the same, and a liquid crystal display panel.

[0002]

2. Description of the Related Art Liquid crystal display panels (LCDs) are widely used as image display elements for televisions, personal computers, word processors, PHSs (Personal Digital Assistants), car navigation systems and the like. Among the liquid crystal display panels, a liquid crystal display panel called a TFT-LCD is capable of responding to a high-speed response and an expansion of a viewing angle, and has a CRT (CRT).
(RT), development of a large-screen TFT-LCD of 13 inches or more is under study.

When manufacturing a large-screen TFT-LCD, in the process of manufacturing a liquid crystal panel, when transporting a substrate, cutting a substrate,
When the liquid crystal panel is transported, the spacers inside the liquid crystal panel move due to vibration or impact, and there is a problem that the display quality of the liquid crystal panel is deteriorated as described below. Disturbance in the alignment of the liquid crystal and damage to the alignment film occur, light leakage increases, and contrast decreases.

[0004] Gap unevenness and color unevenness occur. Adhesive spacers in which the surface of spacer particles is coated with an adhesive have been developed for the purpose of preventing the spacers from moving and falling off. The adhesive spacer is adhered and fixed to the substrate by dry or wet spraying on the substrate and heating (usually at a temperature of 140 to 160 ° C. at which the sealing resin is melted).

[0005] From the viewpoint that the production of the adhesive spacer can be easily carried out, a method of coating the particle surface with a thermoplastic resin by using an impact force has been carried out (JP-A-63-963).
No. 4224, Japanese Unexamined Patent Publication No. 1-154028, Japanese Unexamined Patent Publication No. 8-328022, and Japanese Unexamined Patent Publication No. 9-23552.
No. 7). For the production of the adhesive spacer, a method of grafting the particle surface with a polymer chain using a thermoplastic resin is also performed (JP-A-5-188384, JP-A-5-232480, JP-A-7-300586). JP, JP-A-7-300577, JP-A-7-301
810, JP-A-7-333623, JP-A-8-43834, JP-A-8-48979,
JP-A-8-328018, JP-A-9-24403
No. 4, JP-A-9-194842).

[0006] In the method of grafting the particle surface with a polymer chain, the adhesion between the particle surface and the polymer is strong,
Due to the small molecular weight of the polymer and its small amount, the adhesion between the polymer and the substrate is poor, and the polymer is simply adhered to the substrate. However, there is a problem that it moves easily. Therefore, the above-described method of coating the particle surface with a thermoplastic resin by using an impact force has been studied, but has the following problems (1) and (2).

(1) Although the adhesion between the thermoplastic resin and the substrate is excellent, the adhesion between the particle surface and the polymer is low.
When the CD receives strong vibration or impact, there is a problem that the spacer easily moves. (2) When producing an adhesive spacer, very strong impact (friction) energy is given to the particles and the thermoplastic resin, so that the thermoplastic resin is easily decomposed or depolymerized, and a polymer or oligomer having a low molecular weight is produced. Easy to generate. For this reason, the decomposed polymers and oligomers are likely to remain even when the spacer is washed, and are easily eluted into the liquid crystal as impurities. In a TFT-LCD which is particularly reluctant to mix impurities into the liquid crystal as compared with the STN-LCD. This causes a decrease in the electrical characteristics of the liquid crystal (a decrease in the voltage holding ratio, etc.) and a decrease in the alignment characteristics (a decrease in the pretilt angle), resulting in a decrease in the reliability of the liquid crystal display panel.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to provide an adhesive spacer which is excellent in adhesiveness, hardly mixes impurities into liquid crystal, and enhances the reliability of a liquid crystal display panel, a method of manufacturing the same, and a liquid crystal display. To provide a board.

[0009]

The adhesive spacer for a liquid crystal display panel according to the present invention is obtained by coating at least a part of the surface of a polymer graft particle having a polymer grafted on the surface with a thermoplastic resin. Spacer. The method for producing an adhesive spacer for a liquid crystal display panel according to the present invention includes a grafting step of producing polymer graft particles by grafting the surface of raw material particles with a polymer,
A coating step of coating at least a part of the surface of the polymer graft particles with a thermoplastic resin.

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

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Adhesive spacer for liquid crystal display panel
- : The adhesive spacer for a liquid crystal display panel of the present invention is an adhesive spacer obtained by coating at least a part of the surface of polymer graft particles having a polymer grafted on the surface with a thermoplastic resin. The polymer graft particles are obtained by grafting the surface of the raw material particles. [Raw Material Particles] Raw material particles are used to maintain the thickness of a liquid crystal layer uniform and constant when used in a liquid crystal display panel.

The average particle diameter of the raw material particles is preferably 1 to
It is 30 μm, more preferably 1 to 20 μm, and most preferably 1 to 15 μm. If the average particle diameter is out of the above range, the particles may not be used as an adhesive spacer for a liquid crystal display panel. Coefficient of variation (CV) of particle size of raw material particles
Is preferably 10% or less, more preferably 8% or less,
More preferably, it is at most 6%. Particle size variation coefficient is 1
If it exceeds 0%, it is difficult to keep the thickness of the liquid crystal layer uniform and constant when used for a liquid crystal display panel, and image unevenness is likely to occur.

The definition and measurement method of the average particle diameter and the coefficient of variation of the particle diameter in the present invention are those described in Examples below. The shape of the raw material particles is spherical, acicular,
Any particle shape such as plate-like, scale-like, crushed, bale-like, cocoon-like, confetti-like or the like may be used, and is not particularly limited. However, a spherical shape is preferable in order to make the gap distance of the liquid crystal display plate uniform.
This is because particles that are spherical have a constant or nearly constant particle size in all or almost all directions.

The raw material particles include various types and are not particularly limited. For example, organic cross-linked polymer particles,
Examples include inorganic particles and organic-inorganic composite particles.
Among these, organic cross-linked polymer particles such as vinyl-based cross-linked polymer particles, and organic-inorganic composite particles are used to prevent damage to the electrode substrate, alignment film or color filter, and to ensure uniformity of the gap distance between the two electrode substrates. It is preferable because it is easy to obtain.

The organic crosslinked polymer particles are not particularly limited. For example, at least one selected from the group consisting of benzoguanamine, melamine and urea
Cured particles of amino resin obtained by condensation reaction between various amino compounds and formaldehyde (JP-A-62-06)
No. 8811); divinylbenzene crosslinked resin particles obtained by polymerizing divinylbenzene alone or copolymerizing with other vinyl monomers (see JP-A-1-144429), and monofunctional monomers such as methyl methacrylate. And vinyl-based cross-linked polymer particles such as (meth) acryl-based cross-linked resin particles obtained by copolymerizing a polyfunctional monomer such as glycidyl methacrylate or γ- (meth) acryloxypropyltrimethoxysilane with a dispersion polymerization system. No.

The inorganic particles are not particularly restricted but include, for example, spherical fine particles such as glass, silica and alumina. The organic-inorganic composite particles are organic-inorganic composite particles comprising an organic portion and an inorganic portion. In the organic-inorganic composite particles, the ratio of the inorganic portion is not particularly limited,
For example, with respect to the weight of the organic-inorganic composite particles, preferably 10 to 90 wt% in terms of inorganic oxide,
More preferably 15 to 90 wt%, more preferably 25
８５85 wt%. The term “inorganic oxide equivalent” indicating the proportion of the inorganic portion refers to the percentage by weight determined 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. It is. When the ratio of the inorganic portion of the organic-inorganic composite particles falls below the above range in terms of inorganic oxide, the organic-inorganic composite particles become softer, and the number of particles dispersed on the electrode substrate may increase. In some cases, the alignment film is too hard, and the alignment film is damaged and the TFT is disconnected.

The organic-inorganic composite particles are not particularly limited, and include, for example, an organic polymer skeleton and an organic silicon in which a silicon atom is chemically bonded directly to at least one carbon atom in the organic polymer skeleton. And organic-inorganic composite particles A, which include a polysiloxane skeleton in the molecule, wherein the amount of SiO ₂ constituting the polysiloxane skeleton is 25 wt% or more. The organic-inorganic composite particles A have G ≧ 14 · Y
Preferably, the breaking strength satisfies ^1.75 (where G indicates breaking strength [kg]; Y indicates particle diameter [mm]), and the 10% compression modulus is 300 to 2000 kg / mm.
² , It is more preferable that the residual displacement after 10% deformation is 0 to 5%.

The method for producing the organic-inorganic composite particles A is not particularly limited, and examples thereof include a production method including the following condensation step, polymerization step and heat treatment step. The condensation step is a step of performing hydrolysis and condensation using the first silicon compound having a radical polymerizable group.

The first silicon compound has the following general formula (1):

[0020]

Embedded image

(Wherein, R ^a represents a hydrogen atom or a methyl group; R ^b has 1 to 1 carbon atoms which may have a substituent;
R ^c 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; Show)
And the following general formula (2):

[0022]

Embedded image

(Where R ^d represents a hydrogen atom or a methyl group; ^Re is 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) At least one monovalent group), and the following general formula (3):

[0024]

Embedded image

(Wherein, R ^f represents a hydrogen atom or a methyl group; R ^g represents an optionally substituted C 1 -C 1)
R ^h 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; Show)
And at least one selected from the group consisting of compounds represented by at least one general formula selected from the group consisting of: and derivatives thereof.

The polymerization step is a step in which a radical polymerizable group undergoes a radical polymerization reaction during and / or after the condensation step. The heat treatment step is a step of drying and firing the polymer particles generated in the polymerization step at a temperature of 800 ° C. or less. The heat treatment step is performed, for example, in an atmosphere having an oxygen concentration of 10% by volume or less.

The raw material particles may be colored by containing at least one selected from the group consisting of dyes and pigments. The color is preferably a color through which light is hardly transmitted or a color through which light is not transmitted, since light leakage of the adhesive spacer itself can be prevented and the contrast of image quality can be improved. The color that is difficult to transmit light or does not transmit, for example, black, dark blue, dark blue, purple, blue, dark green, green, brown, red, and the like, 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 raw material particles are linked by a chemical bond. . [Polymer Graft Particles] The polymer graft particles are particles obtained by grafting a polymer on the surface. This polymer enhances the affinity between the raw material particles and the thermoplastic resin described later, improves the adhesiveness of the adhesive spacer, and exerts an action of suppressing the movement of the adhesive spacer when subjected to vibration or impact. . The polymer is, for example, a siloxane bond, an ether bond, a urethane bond, a C—N bond, a Si bond.
It is grafted to the raw material particles via a chemical bond such as a -C bond.

Examples of the polymer include a (meth) acrylic polymer, a (meth) acrylic-styrene-based polymer, a styrene-based polymer and the like. They can coexist. Among these polymers, a polymer composed of the same structural unit as a monomer constituting the thermoplastic resin described later is preferable because the adhesiveness of the spacer is improved. [Thermoplastic resin] The thermoplastic resin coats at least a part of the surface of the polymer graft particles, that is, a part or the whole of the surface, to form an adhesive layer of the thermoplastic resin on the surface of the polymer graft particles. This adhesive layer functions as an adhesive for the electrode substrate and the like.

Examples of the thermoplastic resin include a resin containing a homopolymer or a copolymer of an ethylenically unsaturated monomer. Thermoplastic resin is a resin containing a (meth) acrylic polymer containing (meth) acrylate as an essential component as a monomer unit ((meth) acrylic resin), and a styrene compound as a monomer unit. A resin containing a styrene-based polymer (styrene-based resin),
And a (meth) acryl-containing styrene compound and (meth) acrylate as monomer units as essential components.
At least one selected from the group consisting of a resin containing a styrene-based polymer ((meth) acryl-styrene-based resin)
If it is a seed, it has a large adhesive force to the substrate. As the thermoplastic resin, a (meth) acrylic resin and / or a (meth) acryl-styrene resin are more preferable.

As the thermoplastic resin, a resin containing a polymer containing, as an essential unit, a monomer having a glass transition temperature (Tg) of a homopolymer of 60 ° C. or more is firmly adhered to both upper and lower substrates. It is preferable because it can be easily performed. The Tg of the homopolymer is preferably 70 ° C. or higher, more preferably 8 ° C.
0 ° C. or higher. As the thermoplastic resin, (meth) acrylate or styrene having an alkyl group having 6 or more carbon atoms as a monomer unit is preferably 45% by weight or more (preferably, in terms of improving adhesiveness and suppressing light leakage around the spacer). 50 wt% or more, more preferably 60 wt%
A (meth) acryl-styrene resin containing a (meth) acryl-styrene polymer is preferred.

The ethylenically unsaturated monomer is not particularly restricted but includes, for example, ethylene, propylene, vinyl chloride, vinyl acetate, styrene, vinyltoluene, α-methylstyrene, (meth) acrylate (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, and the like. Among these, when the ethylenically unsaturated monomer contains an aromatic residue (for example, a phenyl group) or a residue capable of hydrogen bonding (an ester group or the like), the intermolecularity with the alignment film is reduced. This is preferred because the force increases and the adhesive strength to the substrate increases, and at least one or more selected from (meth) acrylate and styrene is more preferable.

In particular, when a thermoplastic resin is produced by polymerizing (meth) acrylic acid ester or styrene, one obtained by soap-free polymerization is preferable. The reason for this is that in the soap-free polymerization, no conductive impurities such as a free surfactant are used, so that the reliability of the liquid crystal display panel is easily improved. 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 and the like can also be used as the thermoplastic resin. As the thermoplastic resin, only one of the above-described thermoplastic resins may be present, or two or more may be present together.

The thermoplastic resin is non-reactive with the polymer graft particles, that is, the thermoplastic resin does not have a substituent which reacts with the polymer graft particles, and the thermoplastic resin and the polymer graft particles are not bonded by a chemical bond. It may be. In this case, even if impurities such as low-molecular-weight oligomers and polymers contained in the thermoplastic resin are eluted into the liquid crystal, they have no substituent that reacts with the polymer graft particles. Holding ratio) and a decrease in alignment characteristics may be avoided.

The ratio of the number average molecular weight of the thermoplastic resin and the polymer (thermoplastic resin / polymer) is not particularly limited, but is preferably 1.1 or more, more preferably 1.2 or more, and further preferably It is at least 1.5, most preferably at least 2. When the ratio of the number average molecular weight is 1.
If it is less than 1, the adhesiveness may be reduced. The thermoplastic resin may be colored by including at least one selected from the group consisting of dyes and pigments. Preferred colors include the colors described above as preferred colors of the raw material particles of the spacer. [Adhesive Spacer for Liquid Crystal Display Panel] The average particle size of the adhesive spacer for a liquid crystal display panel of the present invention is not particularly limited, but is preferably more than 1 μm and 32 μm or less, more preferably more than 1 μm and 22 μm or less. More preferably, it is more than 1 μm and 17 μm or less.

The weight ratio of the adhesive layer obtained from the thermoplastic resin is not particularly limited, but is preferably 0.1 to 30%, more preferably 1 to 30% based on the polymer graft particles.
２５25%, most preferably 2-20%. If the weight ratio of the adhesive layer exceeds 30%, the area covering the electrode substrate, the alignment film, and the color filter becomes large when the adhesive layer is melted, and the image quality of the liquid crystal display panel may be deteriorated. On the other hand, when the weight ratio of the adhesive layer is small, the adhesiveness decreases.

The thickness of the adhesive layer is not particularly limited,
Usually, in the range of 0.01 to 2 μm, preferably 0.05 to
The range is 1 μm. If the thickness is smaller than the above range, there is a possibility that the adhesiveness is reduced, and if the thickness is larger than the above range, the area covering the alignment film, the color filter and the like is increased, and the display quality of the liquid crystal display panel is reduced. There is a risk.

The adhesive spacer for a liquid crystal display panel of the present invention can be used in any of wet and dry spraying methods. The adhesive spacer of the present invention has a high chemical affinity between the surface of the polymer graft particles and the thermoplastic resin, so that the adhesiveness is high, and even if a liquid crystal display panel using this adhesive spacer receives a strong impact, The movement of the spacer is prevented. Further, in the adhesive spacer, elution of impurities such as low molecular weight polymers and oligomers derived from the thermoplastic resin into the liquid crystal is suppressed, so that the reliability is high.

The method for producing the adhesive spacer for a liquid crystal display panel of the present invention is not particularly limited, but preferred examples include the production method described in detail below. Method for producing adhesive spacer : The method for producing an adhesive spacer for a liquid crystal display panel according to the present invention includes a grafting step and a coating step. [Grafting Step] The grafting step is a step of producing polymer graft particles by grafting the surface of the raw material particles with a polymer.

The raw material particles used in the grafting step have the constitution of the raw material particles described above, and further have an epoxy group, a hydroxyl group, a carboxyl group, a mercapto group, an amino group, a haloalkyl group, a silanol group, an alkoxysilyl group on the surface. Particles having a functional group such as a group.
Only one type of functional group may be present on the surface of the raw material particles used in the grafting step, and two or more types may be present together.

The raw material particles used in the grafting step are as follows:
The surface may be surface-treated. The method of the surface treatment is not particularly limited, and examples thereof include a method of mixing and heating the core particles serving as nuclei of the raw material particles using, for example, a surface treatment agent described below. As the core particles, those described above as the raw material particles can be used as they are.

Surface treatment agent for introducing an epoxy group:
Epoxy group-containing silane coupling agents such as 3-glycidoxypropyltrimethoxysilane and 3-glycidoxypropylmethyldiethoxysilane. Surface treatment agent for introducing a hydroxyl group: a hydroxyl group-containing silane coupling agent such as hydroxypropyltrimethoxysilane. After the treatment with the epoxy group-containing silane coupling agent, the epoxy group may be opened with an acid or an alkali.

A surface treatment agent for introducing a mercapto group: a silane coupling agent containing a mercapto group such as 3-mercaptopropyltrimethoxysilane. Surface treatment agent for introducing an amino group: a silane coupling agent having a primary or secondary amino group such as 3-aminopropyltrimethoxysilane or 3-aminopropyltriethoxysilane.

Examples of the polymer used in the grafting step include those having the structure of the above-mentioned polymer and further having a reactive group which reacts with the above functional group. The reactive group contained in the polymer used in the grafting step includes, for example, an epoxy group, a hydroxyl group, a carboxy group, a mercapto group, an amino group, a haloalkyl group,
Examples thereof include a silanol group and an alkoxysilyl group. Only one kind may be present, or two or more kinds may be present together.

The specific method for grafting the raw material particles with the polymer is not particularly limited.
A method in which the raw material particles and the polymer are mixed while heating in the presence of a solvent in which the polymer is dissolved, and the functional group of the raw material particles are reacted with the reactive group in the polymer can be used. The grafting step is preferably performed in the liquid phase as described above, and has an advantage that aggregation of the raw material particles can be suppressed. [Coating Step] The coating step is a step of coating at least a part of the surface of the polymer graft particles obtained in the grafting step with a thermoplastic resin.

As the polymer graft particles and the thermoplastic resin used in the coating step, those described above are used. The specific method for forming the adhesive layer by coating the surface of the polymer graft particles with a thermoplastic resin is not particularly limited. For example, the polymer graft particles are dispersed in a solution of the thermoplastic resin and sufficiently stirred. After mixing
A method of removing the solvent by evaporation and pulverizing the obtained lump,
There is a method in which polymer graft particles are dispersed in a molten thermoplastic resin, kneaded and sufficiently dispersed, and after cooling, a lump is crushed.

In addition to the above-mentioned methods, “surface modification”
(Chemical Review No.44, edited by The Chemical Society of Japan, pp. 45-52, published in 1987) and “Powder Surface Modification and Highly Functional Technology” (“Surface”
Ins, which is described in detail in Vol. 25, No. 1, pp. 1 to 19 and a cover photograph, published in 1987), in which a monomer or a polymerization catalyst is localized at a core material interface to form a polymer wall and encapsulate.
Itu polymerization method; Coacervation method for generating concentrated phase dispersed droplets (coacervate); Monomer for polycondensation is separately added to the continuous phase and the dispersed phase of the liquid-liquid dispersion system, and the polymer film is homogeneous at the interface Interfacial polymerization method for forming a liquid; curing method in liquid; drying method in liquid; high-speed bombardment method in a high-speed air stream mixing at high speed in a dry state; air suspension coating method; Can be coated.

In particular, in the high-velocity air impact method, a polymer graft particle and a thermoplastic resin powder are mixed, and this mixture is dispersed in a gas phase. This is a method in which the surface of the polymer graft particles is coated with a thermoplastic resin by applying the particles to the particles and the powder of the thermoplastic resin, and can be easily coated.

The average particle size of the thermoplastic resin powder used when performing the high-speed airflow impact method is not particularly limited, but is preferably 2 μm or less, more preferably 1 μm or less, and most preferably 0.5 μm or less. is there. If the average particle diameter of the thermoplastic resin powder exceeds 2 μm, the surface of the polymer graft particles may not be coated uniformly.

The ratio of the thermoplastic resin powder to the polymer graft particles at the time of performing the high-speed airflow impact method is preferably 0.1 to 30% by weight, more preferably 1 to 25% by weight.
%, Most preferably 2 to 20 wt%. When the proportion of the thermoplastic resin powder exceeds 30 wt%, the thickness of the adhesive layer becomes large, and when melted, the area covering the electrode substrate, the alignment film, the color filter, and the like becomes large, and the image quality of the liquid crystal display panel deteriorates. There is a risk. On the other hand, if the proportion of the thermoplastic resin powder is less than 0.1 wt%, the adhesiveness may be reduced.

The apparatus utilizing the high-speed airflow impact method is not particularly limited. For example, a hybridization system manufactured by Nara Machinery Co., Ltd., a mechanofusion system manufactured by Hosokawa Micron Corporation, and Kawasaki Heavy Industries, Ltd. Kryptron system. In the high-velocity air impact method, a spacer with high adhesiveness is easily obtained, but the impact energy for decomposing and depolymerizing the thermoplastic resin is applied, so low-molecular-weight products, oligomers and monomers of the thermoplastic resin are produced as by-products. Cheap. These by-products are used in a liquid crystal display panel obtained using an adhesive spacer,
It is easily eluted as impurities in the liquid crystal, and the reliability of the liquid crystal display panel is reduced. However, in the adhesive spacer of the present invention, particles having a polymer grafted on the surface are used, thereby reducing impurities derived from the thermoplastic resin and suppressing bleeding to the liquid crystal. And a highly reliable spacer for a liquid crystal display panel.

Next, the liquid crystal display panel of the present invention will be described. Liquid crystal display panel : The liquid crystal display panel of the present invention is the same as the conventional liquid crystal display panel, except that the conventional spacer is replaced with the adhesive spacer for the liquid crystal display panel of the present invention and / or the liquid crystal obtained by the manufacturing method of the present invention. The adhesive spacer for the display panel is interposed between the electrode substrates to maintain the interval between the electrode substrates, and has the same or substantially the same gap distance as the particle diameter of the spacer.

The liquid crystal display panel of the present invention includes, for example, a first electrode substrate, a second electrode substrate, a spacer, a sealing material, and a liquid crystal. The first electrode substrate has a first substrate and a first electrode formed on a surface of the first substrate.
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 serves to maintain a space between the first and second electrode substrates by interposing the first and second electrode substrates. The sealant adheres the first electrode substrate and the second electrode substrate at a peripheral portion. The liquid crystal is sealed between the first electrode substrate and the second electrode substrate, and is filled in a space surrounded by the first electrode substrate, the second electrode substrate, and a sealing material.

For the liquid crystal display panel of the present invention, those other than the spacers, such as an electrode substrate, a sealing material, and a liquid crystal, can be used in the same manner as the conventional one in the same manner. The electrode substrate has a substrate such as a glass substrate and a film substrate, and an electrode formed on the surface of the substrate.If necessary, an alignment film formed on the surface of the electrode substrate so as to cover the electrode is formed. Have more. As the sealing material, an epoxy resin adhesive sealing material or the like is used. As the liquid crystal, those conventionally used may be used, for example, biphenyl, phenylcyclohexane, Schiff base, azo, azoxy, benzoate, terphenyl, cyclohexylcarboxylate, biphenylcyclohexane , Pyrimidine, dioxane, cyclohexylcyclohexane ester, cyclohexylethane, cyclohexene, and fluorine liquid crystals can be used.

As a method of manufacturing the liquid crystal display panel of the present invention, for example, a method in which an adhesive spacer is used as an in-plane spacer and uniformly dispersed on one of the two electrode substrates is used in the present invention. The raw material particles to be dispersed in an adhesive sealing material such as an epoxy resin as a sealing spacer are placed on the adhesive sealing portion of the other electrode substrate by means of screen printing or the like, and an appropriate pressure is applied thereto. After heating and curing the adhesive sealant by heating at a temperature of 160 ° C. for 1 to 60 minutes, a method of injecting liquid crystal, sealing the injected portion, and obtaining a liquid crystal display panel can be mentioned. The present invention is not limited by the method for manufacturing the liquid crystal display panel. As the in-plane spacer, among the adhesive spacers, a colored spacer is preferable because light leakage of the spacer itself does not easily occur.

Since the liquid crystal display panel of the present invention uses the above-mentioned adhesive spacer, the adhesive strength to both the upper and lower substrates is strong, the movement of the spacer is reduced, and the thickness of the liquid crystal layer is made uniform. In addition, color unevenness does not occur, and furthermore, impurities derived from the thermoplastic resin are reduced, and impurities are prevented from being mixed into the liquid crystal, so that display quality and reliability are improved. Therefore, it is suitably used for applications that are susceptible to vibration or shock, for example, for use in vehicles such as car navigation systems, but is used for the same applications as conventional liquid crystal display panels, for example, televisions, personal computers, word processors, PHSs (Personal Digital Assistants). It may be used as an image display device such as.

[0057]

EXAMPLES Examples of the present invention and comparative examples will be shown below, but the present invention is not limited to the following examples. In the following example,
The average particle diameter of the raw material particles and the like, the coefficient of variation of the particle diameter, and the voltage holding ratio (after 50 hours at 500C) were measured by the following methods. Average particle diameter and coefficient of variation of particle diameter : Observing the sample with an electron microscope, actually measuring the particle diameter of 200 samples of the photographed image, and calculating the average particle diameter, the standard deviation of the particle diameter, and the particle according to the following formula. The coefficient of variation of the diameter was determined.

[0058]

(Equation 1)

[0059]

(Equation 2)

[0060]

(Equation 3)

Voltage holding ratio : a pair of patterned IT
Form a polyimide alignment film on a glass substrate with an O electrode,
After performing the rubbing treatment, the liquid crystal cells were bonded to each other so as to have a TN orientation, thereby producing a liquid crystal cell. Next, the initial voltage holding ratio was measured at 25 ° C. using a liquid crystal voltage holding ratio measurement system, and after confirming that the voltage holding ratio was 90% or more, 5
Voltage holding ratio after 500 hours at 0 ° C (measuring temperature: 25 ° C)
Was measured.

Prior to Examples and Comparative Examples, raw material particles were synthesized according to Synthesis Examples 1 to 3, and polymers were synthesized according to Synthesis Examples 4 and 5. Using the obtained raw material particles and the polymer, polymer graft particles were synthesized according to Synthesis Examples 6 to 8. <Synthesis Example 1> Co-hydrolysis of alkoxysilyl group using γ-methacryloxypropyltrimethoxysilane and vinyltrimethoxysilane (45/55 weight ratio)
By performing polycondensation and radical polymerization of double bonds,
White organic-inorganic composite particles (1) having a silanol group on the surface were obtained.

The composite particles (1) have an average particle size of 5.
0 μm, the coefficient of variation of the particle diameter is 3.2%, and the ratio of the polysiloxane skeleton is based on the weight of the composite particles (1).
_It was 55 wt% (when calcined in air at 1000 ° C.) in terms of ₂ equivalents. <Synthesis Example 2> The composite particles (1) obtained in Synthesis Example 1 were dispersed in methanol, 3-aminopropyltriethoxysilane was added and mixed, and the mixture was heated and stirred at a reflux temperature. . After cooling the mixture, methanol contained in the mixture was distilled off while heating using an evaporator. The obtained residue is vacuum-dried at 150 ° C. for 2 hours, washed with methanol several times, filtered, dried and crushed to obtain a white organic-inorganic composite having an amino group on its surface. Particles (2) were obtained. Organic-inorganic composite particles (2) had an average particle diameter of 5.0 μm and a coefficient of variation in particle diameter of 3.5%.

<Synthesis Example 3> Styrene, divinylbenzene and methacrylic acid (60/30) were added to a methanol solution of hydroxypropyl cellulose dissolved in methanol.
/ 10 weight ratio) and 2,2 as a radical polymerization initiator.
And 2'-azobisisobutyronitrile. This mixture was refluxed under a nitrogen atmosphere for 8 hours to carry out precipitation polymerization, thereby obtaining vinyl-based crosslinked polymer particles (3) having a carboxyl group on the surface. Vinyl-based crosslinked polymer particles (3)
Is an average particle diameter of 5.5 μm and a coefficient of variation of the particle diameter is 3.6%.
Met.

<Synthesis Example 4> 12.4 g of γ-methacryloxypropyltrimethoxysilane, 144.4 g of tetramethoxysilane, 100 g of methanol, 18 g of water and Amberlyst 15 as a solid catalyst (manufactured by Rohm and Haas Japan) 5g of ion exchange resin)
The mixture was stirred at 65 ° C. for 2 hours to carry out cohydrolysis and polycondensation of the alkoxysilyl group. After cooling the reaction mixture, methanol was distilled off with an evaporator while heating under reduced pressure, and Amberlyst 15 was separated by filtration to obtain a polymerizable siloxane having a number average molecular weight of 1,800.

Next, the polymerizable siloxane obtained above, styrene and lauryl methacrylate (10/45/4
5% by weight) and 2,2′- as a radical polymerization initiator.
Azobisisobutyronitrile and ethyl cellosolve as a solvent were mixed. This mixture is placed under a nitrogen atmosphere.
Solution polymerization is carried out by heating and stirring at 80 ° C. for 3 hours, and a polymer having a polyalkoxysiloxane group in a side chain (4)
Was obtained (solid content concentration: 50 wt%). The number average molecular weight of this polymer (4) was 8,200.

<Synthesis Example 5> Methyl methacrylate, 2-
Ethylhexyl acrylate, styrene and glycidyl methacrylate (4/16/75/5 weight ratio), 2,2'-azobisisobutyronitrile as a radical polymerization initiator, and toluene as a solvent were mixed. This mixture was heated and stirred at 60 ° C. for 5 hours under a nitrogen atmosphere to perform solution polymerization, and a toluene solution of a polymer (5) having an epoxy group in a side chain (solid content concentration: 50 wt%)
I got The number average molecular weight of this polymer (5) is 2500
It was 0.

<Synthesis Example 6> 40 g of the composite particles (1) having a silanol group on the surface obtained in Synthesis Example 1 were used as raw material particles and dispersed in 500 g of ethyl cellosolve. 16 g of ethyl cellosolve solution (solid content: 16 g) of the polymer (4) having a polyalkoxysiloxane group in the side chain obtained in Synthesis Example 4 was mixed as a polymer with the dispersion obtained above. Ethyl cellosolve was distilled off with an evaporator while heating the obtained mixture, and the obtained residue was vacuum-dried at 120 ° C. for 2 hours and washed several times with ethyl cellosolve to obtain composite particles (1). A polymer graft particle (6) was obtained in which the polymer (4) was grafted on the surface of the polymer.

<Synthesis Example 7> In Synthesis Example 6, the composite particles (2) having an amino group on the surface obtained in Synthesis Example 2 were used as raw material particles, and the side chain obtained in Synthesis Example 5 was used as a polymer. Polymer graft particles (7) obtained by grafting polymer (5) on the surface of composite particles (2) in the same manner as in Synthesis Example 6 except that polymer (5) having an epoxy group was used and toluene was used as a solvent. ) Got.

<Synthesis Example 8> In Synthesis Example 6, the crosslinked polymer particles (3) having a carboxyl group on the surface obtained in Synthesis Example 3 were used as raw material particles, and the side chain obtained in Synthesis Example 5 was used as a polymer. Having an epoxy group on the surface (5)
Synthesis Example 6 except for using toluene and using toluene as a solvent.
In the same manner as in the above, polymer graft particles (8) in which the polymer (5) was grafted on the surface of the crosslinked polymer particles (3) were obtained.

Example 1 35 g of the polymer graft particles (6) obtained in Synthesis Example 6 and methyl methacrylate obtained by soap-free polymerization as a thermoplastic resin powder
Styrene-2-ethylhexyl acrylate copolymer (15/65/20 weight ratio, number average molecular weight 85,000
And 0 g of the powder of 0). After mixing, the surface of the polymer graft particles (6) was treated with methyl methacrylate-styrene-2 by a high-speed airflow impact method (16000 rpm, 5 minutes) using a hybridization system NHS-0 manufactured by Nara Machinery Co., Ltd. -An adhesive spacer (1) coated with a copolymer of ethylhexyl acrylate was obtained.

A liquid crystal cell was prepared using the adhesive spacer (1), and its voltage holding ratio (after 50 hours at 50 ° C.) was measured. As a result, it was 98%, and there was almost no change in the voltage holding ratio. . Next, the adhesive spacer (1)
A 13-inch TFT liquid crystal liquid crystal display panel (1) was prepared using the method described above, and a predetermined voltage was applied. Was.

The liquid crystal display panel (1) is moved along the X axis, the Y axis and the Z axis.
Vibration was performed in the axial direction while applying an acceleration of 2 G for 1 hour each. The in-plane gap uniformity after vibration is good, and no increase in light leakage due to damage to the alignment film due to the movement of the spacer or increase in light leakage around the spacer is observed. , And both were equivalent to those before the vibration. These results are also shown in Table 2.

<Examples 2 to 3> The procedure of Example 1 was repeated except that the type of the polymer graft particles and the type of the thermoplastic resin powder (both were synthesized by soap-free polymerization) were changed to those shown in Table 1. In the same manner as in Example 1, adhesive spacers (2) to (3) were obtained. Using the obtained adhesive spacers (2) and (3), the voltage holding ratio (at 50 ° C., after 500 hours) was measured in the same manner as in Example 1. Further, liquid crystal display panels (2) to (3), which are 13-inch TFT liquid crystal display panels, were prepared in the same manner as in Example 1, and the driving stability and the liquid crystal alignment characteristics, and the in-plane gap after vibration was applied. The uniformity, light leakage due to damage to the alignment film, and light leakage around the spacer were evaluated. These results are shown in Table 2. Table 2 also shows the results of Example 1.

[0075]

[Table 1]

[0076]

[Table 2]

<Comparative Example 1> In Example 3, a crosslinked polymer particle (3) was used instead of the polymer graft particle (8).
A comparative adhesive spacer (1) was obtained in the same manner as in Example 3 except for using. Using the obtained comparative adhesive spacer (1), the voltage holding ratio (50
C., after 500 hours). Further, a comparative liquid crystal display panel (1), which is a 13-inch TFT liquid crystal display panel, was prepared in the same manner as in Example 1, and the driving stability and the alignment characteristics of the liquid crystal, the in-plane gap uniformity after vibration was applied, and the like. Light leakage due to damage to the alignment film and light leakage around the spacer were evaluated. These results are shown in Table 3.

Comparative Example 2 The polymer graft particles (8) obtained in Synthetic Example 8 were directly used as comparative adhesive spacers (2). The obtained comparative adhesive spacer (2)
And a voltage holding ratio (50 ° C., 5
00 hours). Further, a comparative liquid crystal display panel (2), which is a 13-inch TFT liquid crystal display panel, was manufactured in the same manner as in Example 1, and the driving stability, the alignment characteristics of the liquid crystal,
The in-plane gap uniformity after vibration was applied, light leakage due to damage to the alignment film, and light leakage around the spacer were evaluated. These results are shown in Table 3.

<Comparative Example 3> In Example 3, a crosslinked polymer particle (3) was used instead of the polymer graft particle (8).
As a thermoplastic resin powder, a copolymer of methyl methacrylate-styrene-2-ethylhexyl acrylate-glycidyl methacrylate obtained by emulsion polymerization (10/65/20/5 weight ratio, number average molecular weight 10
Comparative adhesive spacer (3) was obtained in the same manner as in Example 3 except that the powder (0000) was used.

Using the obtained comparative adhesive spacer (3), a voltage holding ratio (50 ° C., 500
After hours) was measured. Further, in the same manner as in the first embodiment, 13
Comparative liquid crystal display panel (3 inch) TFT liquid crystal display panel (3)
Were prepared, and the driving stability and the alignment characteristics of the liquid crystal, the uniformity of the in-plane gap after vibration was applied, the light leakage due to the damage of the alignment film, and the light leakage around the spacer were evaluated. These results are shown in Table 3.

[0081]

[Table 3]

[0082]

The adhesive spacer for a liquid crystal display panel according to the present invention has excellent adhesiveness, hardly mixes impurities into the liquid crystal, and can enhance the reliability of the liquid crystal display panel. ADVANTAGE OF THE INVENTION The manufacturing method of the adhesive spacer for liquid crystal display panels which concerns on this invention is excellent in adhesiveness, an impurity hardly mixes in a liquid crystal, and can easily obtain the adhesive spacer which improves the reliability of a liquid crystal display panel.

Since the adhesive spacer is interposed between the electrode substrates, the liquid crystal display panel according to the present invention has excellent adhesiveness, hardly mixes impurities into the liquid crystal, and has high reliability.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Nobuhiko Fujisawa 5-8, Nishiobari-cho, Suita-shi, Osaka Nippon Shokubai Co., Ltd. (72) Inventor Yoshie Omichi 5-8, Nishiobari-cho, Suita-shi, Osaka Company Nippon Shokubai

Claims (6)

[Claims] An adhesive spacer for a liquid crystal display panel, wherein at least a part of the surface of a polymer graft particle having a surface grafted with a polymer is coated with a thermoplastic resin. 2. The adhesive spacer for a liquid crystal display panel according to claim 1, wherein said thermoplastic resin is non-reactive with said polymer graft particles. 3. A liquid crystal comprising: a grafting step of grafting a surface of raw material particles with a polymer to produce polymer graft particles; and a coating step of coating at least a part of the surface of the polymer graft particles with a thermoplastic resin. A method for producing an adhesive spacer for a display panel. 4. The method for producing an adhesive spacer for a liquid crystal display panel according to claim 3, wherein the grafting step is performed in a liquid phase, and the coating step is performed by a high-speed impact in a gas stream. 5. The method for producing an adhesive spacer for a liquid crystal display panel according to claim 3, wherein said thermoplastic resin is non-reactive with said polymer graft particles. 6. A liquid crystal display panel using the adhesive spacer for a liquid crystal display panel according to claim 1 or 2 as a spacer interposed between the electrode substrates.