JP3207046B2 - Liquid crystal display spacer and liquid crystal display device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel liquid crystal display spacer and a liquid crystal display device, and more particularly, to preventing a liquid crystal alignment abnormality around a spacer or between spacers at the time of energization, thereby achieving a uniform display. The present invention relates to a liquid crystal display spacer and a liquid crystal display device that can be used.

[0002]

2. Description of the Related Art A liquid crystal display has a structure as shown in FIG. A transparent electrode 3 patterned in a predetermined shape and an alignment film 4 covering the transparent electrode 3 are provided on the upper and lower glass substrates 2, and a liquid crystal material 5 is injected between the two glass substrates 2. The periphery of the glass substrate is sealed with a sealant 6. To keep the distance between the liquid crystal cells constant, the liquid crystal display spacer 7 is used.
Are uniformly dispersed, and the distance between the liquid crystal cells is generally 1 to 30 μm. Finally, the polarizing plates 1 are provided on both outer sides of the glass substrate 2 to complete a liquid crystal display cell.

Meanwhile, in a TN (twisted nematic) or STN (super twisted nematic) liquid crystal panel, during the energization, an abnormal alignment of the liquid crystal around the spacers or between the spacers occurs, and the region expands with the energization time. Although the reason is not clear, it is presumed to be caused by the interaction between the liquid crystal molecules and the surface of the liquid crystal spacer. Furthermore, when the protective film is removed, static electricity is easily generated, which often causes a problem that abnormal alignment of liquid crystal molecules occurs around the spacer. To prevent these,
In the production of liquid crystal panels, a so-called aging operation (annealing step) of the liquid crystal panel is performed, but there are problems such as a decrease in production efficiency.

Further, the critical surface energy is 30 dyn / cm
A method using the following spacer (JP-A-2-297523),
A method of treating the spacer surface with a long-chain alkylsilane or the like (JP-A-4-177324, JP-A-5-232478) has been proposed. These methods attempt to vertically align liquid crystal molecules on the spacer surface by imparting an alignment forcing force to the spacer surface. However, according to these methods, the alignment force is too strong, so that even during light transmission, the alignment of the liquid crystal molecules tends to remain vertical to the spacer surface, that is, horizontal to the substrate. This often caused a decrease in contrast around the spacer. In addition, it has no effect on the alignment abnormality of the liquid crystal molecules around the spacer due to the charging of the spacer from static electricity.

[0005]

Means for Solving the Problems The present inventors have solved the above-mentioned drawbacks of the prior art, and have obtained a liquid crystal spacer and a liquid crystal display device in which no abnormal liquid crystal alignment occurs around and between the liquid crystal spacers. As a result of intensive studies, the present invention has been completed. That is, in the present invention, at least the surface is represented by the following general formula (1) RO- (1) (wherein, R represents a linear or branched alkyl group or acyl group having 1 to 18 carbon atoms). With a hydrophobic group, the following general formula (2)

[0006]

Embedded image

(Wherein, R ₁ represents a linear or branched alkylene group having 2 to 4 carbon atoms, and may be substituted with a hydroxy group. M represents an integer of 1 or more and 30 or less; R ₁ may be the same or different.) A liquid crystal display spacer comprising fine particles having a hydrophilic group represented by the following formula: and a liquid crystal comprising the liquid crystal display spacer. A display device is provided.

The fine particles according to the present invention having a hydrophobic group represented by the general formula (1) and a hydrophilic group represented by the general formula (2) on at least the surface thereof can be produced, for example, by the following production method 1. To 4 can be produced.

The general formula used in the following production method
Examples of the monomer having a hydrophobic group represented by (1) (hereinafter abbreviated as hydrophobic monomer (1)) include, for example, methyl vinyl ether, ethyl vinyl ether, n-butyl vinyl ether, isobutyl vinyl ether, 2-ethylhexyl 1 carbon atoms such as vinyl ether and stearyl vinyl ether
Alkyl vinyl ethers having a linear or branched alkyl group of -18, vinyl acetate, vinyl propionate, vinyl valerate, vinyl pivalate, vinyl caprylate, vinyl caprate, vinyl laurate, vinyl myristate, vinyl palmitate And vinyl esters of linear or branched carboxylic acids having 1 to 18 carbon atoms, such as ethyl (meth) acrylate, n-butyl (meth) acrylate, isobutyl (meth) acrylate, and 2-ethylhexyl (meth).
Examples thereof include linear or branched alkyl esters of (meth) acrylic acid having 1 to 18 carbon atoms, such as acrylate, lauryl (meth) acrylate, and stearyl (meth) acrylate. These hydrophobic monomers (1) can be used alone or in combination of two or more.

The monomer having a hydrophilic group represented by the general formula (2) (hereinafter abbreviated as hydrophilic monomer (2)) includes, for example, hydroxyethyl (meth) acrylate,
Hydroxypropyl (meth) acrylate, polyethylene glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate, polytetramethylene glycol mono (meth) acrylate, polyethylene glycol polypropylene glycol mono (meth)
Examples include acrylate, polyethylene glycol polytetramethylene glycol mono (meth) acrylate, and polypropylene glycol polytetramethylene glycol mono (meth) acrylate. These hydrophilic monomers (2) can be used alone or in combination of two or more.

<Production Method 1> The present method comprises the steps of:
This is a method of polymerizing (1) and the hydrophilic monomer (2) with a radically polymerizable monomer other than these by suspension polymerization, seed polymerization or the like. Radical polymerizable polymerizable monomers other than the hydrophobic monomer (1) and the hydrophilic monomer (2) include crosslinkable monomers and non-crosslinkable monomers. The crosslinkable monomer is not particularly limited as long as it is a crosslinkable monomer having two or more radically polymerizable unsaturated double bonds. Examples thereof include divinylbenzene and 1,4-divinyloxy. Vinyl compounds such as butane and divinyl sulfone; allyl compounds such as diallyl phthalate, diallyl acrylamide, triallyl (iso) cyanurate and triallyl trimellitate; (poly) ethylene glycol di (meth) acrylate, (poly) propylene glycol di (meth) ) (Poly) alkylene glycol di (meth) acrylates such as acrylates; pentaerythritol tetra (meth) acrylate, pentaerythritol tri (meth) acrylate, pentaerythritol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, dipe And pentaerythritol hexa (meth) acrylate, dipentaerythritol penta (meth) acrylate, glycerol tri (meth) acrylate, and glycerol di (meth) acrylate. These crosslinkable monomers can be used alone or in combination of two or more.

As the non-crosslinkable monomer, all vinyl monomers other than the radically polymerizable crosslinkable monomer, the hydrophobic monomer (1) and the hydrophilic monomer (2) can be used. For example, styrene, p- (m-) methylstyrene,
p- (m-) ethylstyrene, p- (m-) chlorostyrene, p- (m-) chloromethylstyrene, styrenesulfonic acid, p- (m-) t-butoxystyrene, α-methyl-pt -Styrene monomers such as amyloxystyrene and pt-amyloxystyrene; (meth) acrylate monomers such as glycidyl (meth) acrylate, dimethylaminoethyl (meth) acrylate and diethylaminoethyl (meth) acrylate; ( Meta)
Unsaturated carboxylic acid monomers such as acrylic acid and maleic acid; N-alkyl-substituted (meth) such as N-methyl (meth) acrylamide and N-ethyl (meth) acrylamide
Acrylamide; and nitrile monomers such as (meth) acrylonitrile. These non-crosslinkable monomers can be used alone or in combination of two or more.

The mixing ratio of the crosslinkable monomer and the non-crosslinkable monomer in the present method can be appropriately selected according to the intended use and physical properties of the polymer fine particles. It is preferable that the crosslinkable monomer is used in an amount of 5% by weight or more, more preferably 30% by weight or more, and further preferably 50% by weight or more of all monomers. When the amount of the crosslinkable monomer is less than 5% by weight, the strength of the obtained polymer fine particles is not sufficient, which causes color unevenness when incorporated into a liquid crystal display panel. Also, hydrophobic monomer
The mixing ratio of (1) and the hydrophilic monomer (2) is 3% of all the monomers, respectively, in order to obtain a sufficient effect of preventing abnormal liquid crystal alignment.
It is preferable to use at least 5% by weight, preferably at least 5% by weight. The amounts of the hydrophobic monomer (1) and the hydrophilic monomer (2) need not be equivalent, and can be used in any ratio depending on the type of each monomer used.

As the radical polymerization initiator used in the polymerization of the present method, generally used oil-soluble polymerization initiators can be used. For example, benzoyl peroxide, lauroyl peroxide, o
Peroxide initiators such as chlorobenzoyl peroxide and o-methoxybenzoyl peroxide; azo compounds such as 2,2-azobisisobutyronitrile and 2,2-azobis (2,4-dimethylvaleronitrile) Initiators can be used.

In the present method, the suspension polymerization is preferably carried out in an aqueous system, and a solution prepared by dissolving an initiator in a monomer in advance in the presence of a dispersion stabilizer at a temperature of 25 to 10
The reaction is carried out at 0 ° C, more preferably at 50 to 95 ° C. Examples of the dispersion stabilizer include water-soluble polymers such as gelatin, starch, hydroxyethyl cellulose, carboxymethyl cellulose, polyvinyl pyrrolidone, polyvinyl alkyl ether, and polyvinyl alcohol; barium sulfate, calcium sulfate, barium carbonate, calcium carbonate, magnesium carbonate, and calcium phosphate. Poorly water-soluble inorganic salts such as
In order to further enhance the dispersion stability, various surfactants such as sodium lauryl sulfate, sodium laurylbenzenesulfonate, and sodium polyoxyethylene lauryl ether sulfate may be added. In addition to the above suspension polymerization method, for example, a seed polymerization method as disclosed in JP-A-1-81810 can be used. That is, the seed polymer particles dispersed in the aqueous dispersion medium absorb the hydrophobic monomer (1), the hydrophilic monomer (2), and a radically polymerizable polymerizable monomer other than these, and polymerize. The polymerization can be carried out in the presence of an initiator.

<Production method 2>
When suspension polymerizing a non-crosslinkable monomer and a crosslinkable monomer capable of radical polymerization other than (1) and the hydrophilic monomer (2), the polymerization rate is less than 90%, preferably 10%. % Or more and less than 90%, a method in which the hydrophobic monomer (1) and the hydrophilic monomer (2) are simultaneously or separately added together with the polymerization initiator and copolymerized.

The combination of a non-crosslinkable monomer and a crosslinkable monomer capable of radical polymerization other than the hydrophobic monomer (1) and the hydrophilic monomer (2) used in the present method is styrene / Styrene-based monomers such as divinylbenzene, styrene / ethylene glycol dimethacrylate, styrene / butadiene /
Crosslinkable monomers; (meth) acrylate monomers such as glycidyl (meth) acrylate / divinylbenzene, dimethylaminoethyl (meth) acrylate / ethylene glycol dimethacrylate, diethylaminoethyl (meth) acrylate / methylenebisacrylamide / crosslinking Water-soluble monomer: ethylene / butadiene, vinyl chloride /
Examples include a combination of an olefin-based monomer such as divinyloxybutane / a crosslinkable monomer.

In the present method, these hydrophobic monomers
When polymerizing a non-crosslinkable monomer and a crosslinkable monomer capable of radical polymerization other than (1) and the hydrophilic monomer (2), the polymerization rate is less than 90%, preferably 10% or more. If less than 90%, the hydrophobic monomer (1) and the hydrophilic monomer (2) are added simultaneously or separately together with a polymerization initiator to carry out copolymerization. At this time, as a crosslinkable monomer, ethylene glycol di (meth) acrylate, diethylene glycol di (meth) acrylate, trimethylolpropane tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, divinyloxybutane, etc. The copolymerization may be performed by adding a functional monomer. Further, as a method of adding a polymerization initiator mixture of the hydrophobic monomer (1) and the hydrophilic monomer (2), the hydrophobic monomer (1) and the hydrophilic monomer (2) are simultaneously added. A method of adding them or a method of adding them separately, for example, a method of mixing and polymerizing one of them with another polymerizable monomer in advance and adding the other during the polymerization may be used.

Hydrophobic monomer (1) and / or hydrophilic monomer
Even if (2) is added at a time when the polymerization rate of the polymer fine particles exceeds 90%, the effect of the present invention is hardly obtained, and irregular shaped particles may be generated depending on the addition amount, which is not preferable.
The conversion was determined by the following gravimetric method. That is,
A dispersion of a fixed weight is sampled from a polymerization tank during the synthesis of the crosslinked polymer fine particles, and dispersed in a large amount of methanol (containing 1000 ppm of hydroquinone monomethyl ether). The obtained precipitate was isolated by a method such as filtration or centrifugation and dried under reduced pressure, and the polymerization rate was determined by the following formula.

[0020]

(Equation 1)

The weight of the monomer in the polymerization dispersion (g) is the weight of the sampled dispersion (g) × the concentration of the charged monomer (%).

Hydrophobic monomer (1) and / or hydrophilic monomer
As a method for adding (2), these monomers may be added as they are, or may be added using an emulsion dispersed in a surfactant aqueous solution such as sodium lauryl sulfate using a homomixer or the like. The amount of the hydrophobic monomer (1) and the amount of the hydrophilic monomer (2) to be added in the present method are 3 to 10 parts per 100 parts by weight of the other polymerizable monomer mixture.
0 parts by weight, more preferably 5 to 50 parts by weight. If the amount is less than 3 parts by weight, polymer fine particles having a sufficient effect of preventing abnormal liquid crystal alignment cannot be obtained. If the amount is more than 100 parts by weight, problems such as aggregation of the polymerization system tend to occur, which is not preferable.

<Production method 3>
(1) and a non-crosslinkable monomer other than the hydrophilic monomer (2) and a crosslinked polymer fine particle comprising a copolymer of a crosslinkable monomer, the hydrophobic monomer (1) and After impregnating the hydrophilic monomer (2) and the crosslinkable monomer and the polymerization initiator, or further polymerization,
Alternatively, one of the hydrophobic monomer (1) and the hydrophilic monomer (2) and a polymerizable monomer other than the hydrophobic monomer (1) and the hydrophilic monomer (2) may be used. A method of impregnating the crosslinked polymer fine particles comprising a polymer with the other of the hydrophobic monomer (1) and the hydrophilic monomer (2), the crosslinkable monomer and the polymerization initiator, and then further polymerizing the polymer. It is.

The copolymer of the non-crosslinkable monomer other than the hydrophobic monomer (1) and the hydrophilic monomer (2) and the crosslinkable monomer used in the present method includes styrene / divinyl benzene,
Styrene-based crosslinked copolymers such as styrene / ethylene glycol dimethacrylate and styrene / butadiene; glycidyl (meth) acrylate / divinylbenzene, dimethylaminoethyl (meth) acrylate / ethylene glycol dimethacrylate, diethylaminoethyl (meth)
(Meth) acrylic ester-based crosslinked copolymers such as acrylate / methylenebisacrylamide; and olefin-based crosslinked copolymers such as ethylene / butadiene and vinyl chloride / divinyloxybutane.

Hydrophobic monomer for crosslinked polymer fine particles
The addition amount of (1) and the hydrophilic monomer (2) is preferably 1 to 100 parts by weight, more preferably 3 to 50 parts by weight, based on 100 parts by weight of the crosslinked polymer fine particles. When the amount is less than 1 part by weight, polymer fine particles having a sufficient effect of preventing abnormal liquid crystal alignment cannot be obtained.

The solvent used for the impregnation may be a solvent in which these monomers are soluble and in which the crosslinked polymer fine particles are not dissolved. Among them, a solvent that swells the crosslinked polymer fine particles is more preferable. For example, tetrachloroethane, dichloroethane, toluene, DMF (dimethylformamide), DM
Solvents such as SO (dimethylsulfoxide) and THF (tetrahydrofuran) are more preferably used, and the impregnation is performed at a temperature of about room temperature to about 40 ° C. Further, in a solvent such as methanol or ethanol, dispersed / dissolved crosslinked polymer fine particles, a hydrophobic monomer (1) and / or a hydrophilic monomer (2), and a polymerization initiator,
The solvent may be distilled off under reduced pressure at a temperature of room temperature to about 40 ° C. to perform the impregnation.

In the above-mentioned method of mixing a polymerization initiator and a monomer and impregnating the crosslinked polymer fine particles, a known polymer soluble in these solvents, for example, polyvinyl alcohol, polytetrahydrofuran, polyethylene oxide, Propylene oxide, ethyleneimine, polyvinylpyrrolidone, poly (N-ethyleneimine) and the like may be added. The solvent used for the polymerization after the impregnation treatment is not particularly limited as long as the hydrophobic monomer (1), the hydrophilic monomer (2) and the crosslinkable monomer are insoluble. Water to which salts have been added, or an aliphatic hydrocarbon-based solvent such as hexane or cyclohexane is used. In the polymerization step, various surfactants or protective colloids may be used to improve the dispersion stability of the polymer particles.

As the polymerization initiator that can be used in the above-mentioned production methods 2 and 3, oil-soluble polymerization initiators generally used as in production method 1 can be used. For example, peroxide initiators such as benzoyl peroxide, lauroyl peroxide, o-chlorobenzoyl peroxide, o-methoxybenzoyl peroxide, 2,2-azobisisobutyronitrile, 2,2-azobis (2 Azo initiators such as 2,4-dimethylvaleronitrile) can be used. In addition, the said manufacturing method 1
Usually, the amount of the polymerization initiator used in (3) is preferably 0.1 to 10 parts by weight based on 100 parts by weight of the polymerizable monomer.

<Production Method 4> The present method furthermore reliably and easily provides a hydrophobic group represented by the general formula (1) and a hydrophilic group represented by the general formula (2) on the surface. This is a method for obtaining polymer fine particles having a group, and when the suspension-polymerizable radically polymerizable monomer other than the hydrophobic monomer (1) and the hydrophilic monomer (2) is subjected to suspension polymerization, the dispersion is stable. As the agent, a copolymer containing both the hydrophobic monomer (1) and the hydrophilic monomer (2) as a component, or a hydrophobic monomer (1) or a hydrophilic monomer ( 2) and, when suspension polymerizing a radically polymerizable polymerizable monomer other than the hydrophobic monomer (1) and the hydrophilic monomer (2), as a dispersion stabilizer, This is a method in which polymerization is performed using a copolymer containing the other of the hydrophobic monomer (1) or the hydrophilic monomer (2) as a constituent, and the dispersion stabilizer is grafted on the particle surface. Examples of the dispersion stabilizer used in the present method include a hydrophobic monomer (1) and / or a hydrophilic monomer (2) and a monomer constituting a water-soluble polymer, for example, hydroxyethyl (meth). (Meth) acrylic acid; (meth) acrylamide or a methylol compound thereof; copolymers such as vinylpyrrolidone and ethyleneimine having a nitrogen atom or a heterocycle thereof. No. These copolymers can be synthesized by a known method. For example, the method described in “Experimental method for polymer synthesis” published by Kagaku Doujin, p. Of methanol solution of ".

A hydrophobic monomer (1) and / or a hydrophilic monomer (2) in the copolymer used as a dispersion stabilizer,
The ratio of the monomers constituting the water-soluble polymer depends on the type of the monomers used and the water solubility, but both the hydrophobic monomer (1) and the hydrophilic monomer (2) are copolymerized. When used as a constituent component of the copolymer, the hydrophobic monomer (1) is 5 to 70 mol%, preferably 5 to 60 mol%, more preferably 10 to 10 mol%, based on all monomers constituting the copolymer. -50 mol%, hydrophilic monomer (2) is 5-95 mol%, preferably 10-95 mol%, more preferably 20-90 mol%, and other hydrophilic monomers are 0-90 mol%.
It is desirable that When the amount of the hydrophobic monomer (1) and the amount of the hydrophilic monomer (2) are less than 5 mol%, polymer fine particles having a sufficient effect of preventing abnormal liquid crystal alignment cannot be obtained. When the amount of the monomer (1) is more than 70 mol%, the water solubility of the obtained copolymer is remarkably reduced, which is not preferable. When the copolymer used as the dispersion stabilizer contains either the hydrophobic monomer (1) or the hydrophilic monomer (2) as a component, the upper limit of each ratio is limited to the obtained copolymer. From the viewpoint of the water solubility of the copolymer, 70 mol% of the hydrophobic monomer (1) was added to all the monomers constituting the copolymer,
It is preferably 60 mol%, more preferably 50 mol%, and desirably 100 mol% for the hydrophilic monomer (2).

As the above-mentioned copolymer used as a dispersion stabilizer, a copolymer having high affinity and adsorptivity to oil droplets and the surface of growing particles before polymerization and high water solubility can be appropriately selected. The molecular weight of the dispersion stabilizer is preferably 10,000 or more and 1,000,000 or less, more preferably 700,000 or less. When the molecular weight is too low, a sufficient polymerization stabilizing effect cannot be obtained, and when the molecular weight is too high, the water solubility is lowered, which is not preferable. The use amount of the dispersion stabilizer is usually 0.1 to 5% by weight based on a dispersion medium such as water, but in the present method, it may be used up to 10% by weight for the purpose of increasing the graft amount on the particle surface. Usually, the monomer concentration in this case is 5 to 20% by weight, preferably 7 to 15% by weight, based on water. When the amount of the dispersion stabilizer is less than 0.1% by weight, sufficient dispersion stability and the effect of preventing abnormal liquid crystal alignment cannot be obtained. When the amount is more than 10% by weight, the graft amount does not increase. It is not preferable because the operability and the like are deteriorated due to the increase in the viscosity.

The radically polymerizable polymerizable monomer other than the hydrophobic monomer (1) and the hydrophilic monomer (2) used in the present method includes the crosslinkable monomer exemplified in the production method 1. Alternatively, a non-crosslinkable monomer can be used. Further, in the present method, a peroxide-based polymerization initiator can be suitably used as the polymerization initiator in that the surface graft amount of the dispersion stabilizer is larger than that of the azo-based polymerization initiator. The graft amount of the dispersion stabilizer onto the surface of the polymer fine particles is determined, for example, in the case of a copolymer with a compound having a nitrogen atom such as vinylpyrrolidone, by quantifying the amount of nitrogen per unit weight of the polymer particles with a nitrogen analyzer. Can be approximated.

Further, a copolymer of a hydrophobic monomer (1) and / or a hydrophilic monomer (2) and a monomer constituting a water-soluble polymer is used as a dispersion stabilizer to perform surface grafting. A method in which both the hydrophobic monomer (1) and the hydrophilic monomer (2) are used as constituent units of the dispersion stabilizer, and a method in which the hydrophobic monomer (1)
Alternatively, the method may be carried out using either one of the hydrophilic monomers (2) as a constituent unit of the dispersion stabilizer and the other as a polymerizable monomer for suspension polymerization. In the latter case, preferably, the hydrophobic group hardly appears on the particle surface in the aqueous suspension polymerization, so the hydrophobic monomer (1) is used as a structural unit of the dispersion stabilizer, and the hydrophilic monomer (2) is used. Is used as a polymerizable monomer for suspension polymerization.

The liquid crystal display device of the present invention uses the fine particles obtained as described above as a liquid crystal spacer. The average particle diameter of the fine particles used as the spacer varies depending on the purpose and the type of the liquid crystal display panel, but is usually about 2 to 10 μm. When a fine particle having a wide particle size distribution is incorporated in a liquid crystal display panel, the distance between two transparent electrodes in the panel cannot be kept constant, which causes color unevenness during display. The standard deviation of the particle size distribution is
It is preferably at most 20%, more preferably at most 10%. Therefore, when the particle size distribution of the obtained crosslinked polymer fine particles is wide, it is preferable to classify by the elutriation method or the wind method.

[0035]

EXAMPLES Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited to these examples. In addition, in an Example, a part shows a weight part.

Example 1 "Experimental method for polymer synthesis" published by Kagaku Dojin, p.139, Experimental Example 50
7 According to “Methanol solution polymerization of vinyl acetate”, a vinyl butyrate / vinyl pyrrolidone copolymer (molar ratio 1: 1, molecular weight 220,000) was obtained. 65 parts of divinylbenzene (purity 81%, DVB-810 manufactured by Nippon Steel Chemical Co., Ltd.), 10 parts of ethylene glycol dimethacrylate (NK-ester 1G manufactured by Shin-Nakamura Chemical Co., Ltd.), polyethylene glycol monomethacrylate (Nippon Yushi) As a dispersion stabilizer, a 5% aqueous solution of the above-mentioned vinyl butyrate / vinylpyrrolidone copolymer 800 was added to a mixture of 25 parts of Blenmer PE350, average molar number of added EO m = 8) and 800 parts of benzoyl peroxide. Part, finely disperse the mixture, carry out suspension polymerization at 80 ° C. for 15 hours under a nitrogen stream with stirring, perform classification operation, average particle diameter 6.3 μm, standard deviation 0.5
Thus, crosslinked polymer fine particles having a particle size of μm were obtained. The obtained crosslinked polymer fine particles were washed with ion-exchanged water and a solvent, then isolated and dried to obtain a liquid crystal display spacer. Using the spacer obtained by the above method, a super twist type liquid crystal display device having a cell size of about 10 inches, a number of dots of 640 × 480, and a cell gap of 6.0 μm was prepared. When a scanning voltage was applied to this display device and its display characteristics were observed, a high-quality display with no display unevenness was obtained over the entire surface. I was not able to admit.

Example 2 In the same manner as in Example 1, a stearyl vinyl ether / hydroxyethyl methacrylate copolymer (molar ratio 1:
9, molecular weight 350,000). Suspension polymerization was carried out in the same manner as in Example 1 except that 100 parts of divinylbenzene was used as a monomer, and the above stearyl vinyl ether / hydroxyethyl methacrylate copolymer was used as a dispersion stabilizer. The average particle diameter was 6.5 μm, and the standard deviation was Was 0.5 μm. For a liquid crystal display device using the obtained spacer, a liquid crystal display device was prepared in the same manner as in Example 1. When a scanning voltage was applied to the obtained display device and its display characteristics were observed, a high-quality display without display unevenness was obtained over the entire surface, and the alignment of the liquid crystal around the spacers and between the spacers was obtained. No abnormalities were observed.

Example 3 Divinylbenzene (purity 81%, DVB manufactured by Nippon Steel Chemical Co., Ltd.)
-810) 80 parts, vinyl valerate 10 parts, polyethylene glycol polypropylene glycol monomethacrylate (manufactured by NOF CORPORATION, Blemmer 70PEP-350B, average EO addition mole number 7, average PO addition mole number 3) 10 parts, 2, To a mixture of 1.0 part of 2-azobisisobutyronitrile was added polyvinyl alcohol (GH-17, manufactured by Nippon Synthetic Chemical Industry Co., Ltd .;
(89 mol%) 3% aqueous solution (800 parts) was added and finely dispersed, suspension polymerization was carried out at 80 ° C for 15 hours under a nitrogen stream, and classification was performed. The combined fine particles were obtained. For a liquid crystal display device using the obtained spacer, a liquid crystal display device was prepared in the same manner as in Example 1. When a scanning voltage was applied to the obtained display device and its display characteristics were observed, a high-quality display without display unevenness was obtained over the entire surface, and the alignment of the liquid crystal around the spacers and between the spacers was obtained. No abnormalities were observed.

Example 4 30 parts of styrene, 70 parts of divinylbenzene (81% purity), 2,2
In a mixture of 1.0 part of 2-azobisisobutyronitrile, add polyvinyl alcohol (GH-17, Nippon Synthetic Chemical Industry Co., Ltd.).
800 parts of a 3% aqueous solution having a saponification degree of 86.5 to 89 mol%) was added and finely dispersed, and polymerization was carried out at 80 ° C. for 1 hour in a nitrogen stream while stirring. The polymerization rate at this time was determined by a gravimetric method, and was 36.3%. To this polymerization system, 1.0 part of 2,2-azobisisobutyronitrile, 10 parts of ethylene glycol dimethacrylate (NK-ester 1G manufactured by Shin-Nakamura Chemical Co., Ltd.)
Part, 2-ethylhexyl methacrylate 20 parts, polyethylene glycol monomethacrylate (Nippon Oil & Fats Co., Ltd. Blenmer PE200, average EO addition mole number m = 4-5) 20
Parts, sodium lauryl sulfate 1.5 parts, ion-exchanged water 200
An emulsion obtained by sonicating the mixture consisting of parts was added, and polymerization was carried out at 80 ° C. for 12 hours under a nitrogen stream while stirring. After washing the obtained fine particles with ion-exchanged water and a solvent,
Perform a classification operation, further isolate and dry, average particle size 6.1μm
Thus, a liquid crystal display spacer having a standard deviation of 0.4 μm was obtained. For a liquid crystal display device using the obtained spacer, a liquid crystal display device was prepared in the same manner as in Example 1. When a scanning voltage was applied to the obtained display device and its display characteristics were observed, a high-quality display without display unevenness was obtained over the entire surface, and the alignment of the liquid crystal around the spacers and between the spacers was obtained. No abnormalities were observed.

Example 5 As a monomer, 20 parts of styrene, 40 parts of divinylbenzene (purity: 81%, DVB-810 manufactured by Nippon Steel Chemical Co., Ltd.), ethylene glycol dimethacrylate (manufactured by Shin-Nakamura Chemical Co., Ltd.)
NK-Ester 1G) In the same manner as in Example 3 except for using 40 parts, the average particle diameter was 6.2 μm, and the standard deviation was 0.5 μm.
Was obtained. 10 parts of the obtained crosslinked polymer fine particles were dispersed in 30 parts of DMF, and 0.2 parts of 2,2-azobisisobutyronitrile, 0.5 parts of ethylene glycol dimethacrylate, 2 parts of lauryl methacrylate, polyethylene glycol polytetramethylene glycol monomethacrylate were used. (Nippon Yushi Co., Ltd., Blemmer 55PET-800,
Average EO addition mole number 10, average BO addition mole number 5) Add 2 parts
After stirring at 35 ° C. for 15 hours, the crosslinked polymer fine particles were impregnated with a polymerization initiator, a hydrophobic monomer (1), a hydrophilic monomer (2) and a crosslinkable monomer. This solution was filtered, and the obtained polymer was redispersed in 200 parts of cyclohexane, and Rheodol SP-
0.2 parts of S10 (a nonionic surfactant manufactured by Kao Corporation) was added, and the polymerizable monomer was polymerized at 62 ° C. for 15 hours. The obtained fine particles were washed with ion-exchanged water and a solvent, and then isolated and dried to obtain a liquid crystal display spacer. For a liquid crystal display device using the obtained spacer, a liquid crystal display device was prepared in the same manner as in Example 1. When a scanning voltage was applied to the obtained display device and its display characteristics were observed, a high-quality display without display unevenness was obtained over the entire surface, and the alignment of the liquid crystal around the spacers and between the spacers was obtained. No abnormalities were observed.

Comparative Example 1 20 parts of styrene and divinylbenzene (purity as monomers)
Suspension polymerization was carried out in the same manner as in Example 3 by using 80 parts of 80 parts), and a classification operation was performed. The average particle diameter was 6.2 μm, and the standard deviation was
Crosslinked polymer fine particles having a size of 0.5 μm were obtained. The obtained crosslinked polymer fine particles were washed with ion-exchanged water and a solvent, then isolated and dried to obtain a liquid crystal display spacer. In the case of the liquid crystal display device using the obtained spacer, a liquid crystal display device was manufactured in the same manner as in Example 1, and the display characteristics were observed. Grade decline was observed.

Comparative Example 2 A liquid crystal display having an average particle diameter of 6.1 μm and a standard deviation of 0.4 μm in the same manner as in Comparative Example 1 except that the vinyl butyrate / vinylpyrrolidone copolymer of Example 1 was used as the dispersion stabilizer. Spacers were obtained. In the case of the liquid crystal display device using the obtained spacer, a liquid crystal display device was manufactured in the same manner as in Example 1, and the display characteristics were observed. As a result, the alignment abnormality between the spacers was almost improved. The display quality was reduced around the spacer.

Comparative Example 3 Instead of vinyl butyrate / vinyl pyrrolidone copolymer, vinylpyrrolidone (BASF, Rubiscol) was used as a dispersion stabilizer.
A liquid crystal display spacer having an average particle size of 6.2 μm and a standard deviation of 0.4 μm was obtained in the same manner as in Example 1 except that K17) was used. In the case of a liquid crystal display device using the obtained spacers, a liquid crystal display device was manufactured in the same manner as in Example 1, and the display characteristics were observed. Grade decline was observed.

[0044]

As is clear from the results of the above embodiments, the liquid crystal display spacer obtained by the present invention is excellent in the effect of preventing abnormal liquid crystal alignment around the spacer and between the spacers. It is suitable as a spacer.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating an example of a liquid crystal display device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Polarizer 2 Glass substrate 3 Transparent electrode 4 Alignment film 5 Liquid crystal material 6 Sealant 7 Spacer

Claims (6)

(57) [Claims] At least on the surface, hydrophobic represented by the following general formula (1) RO- (1) (wherein R represents a linear or branched alkyl group or acyl group having 1 to 18 carbon atoms). And the following general formula (2): (Wherein, R ₁ represents a linear or branched alkylene group having 2 to 4 carbon atoms, and may be substituted with a hydroxy group. M is 1
It represents an integer of 30 or more, and m R _{1 s} may be the same or different. A liquid crystal display spacer comprising fine particles having a hydrophilic group represented by the formula (1). 2. A liquid crystal display spacer comprising, on at least a surface thereof, a hydrophobic group represented by the following general formula (1) RO- (1) (wherein R is as defined above); (2) (Wherein, R ₁ and m have the same meanings as above.) A fine particle having a hydrophilic group represented by the formula: 3. Fine particles having a hydrophobic group represented by the general formula (1) and a hydrophilic group represented by the general formula (2) on at least the surface thereof are represented by the general formula (1). A monomer having a hydrophobic group (hereinafter abbreviated as hydrophobic monomer (1)) and a monomer having a hydrophilic group represented by the general formula (2) (hereinafter referred to as hydrophilic monomer (2) The spacer for liquid crystal display according to claim 1, wherein the spacer is obtained by suspension polymerization of a) and a polymerizable monomer other than these. 4. Fine particles having a hydrophobic group represented by the general formula (1) and a hydrophilic group represented by the general formula (2) on at least the surface thereof are formed of a hydrophobic monomer (1) and a hydrophobic monomer (1). Hydrophilic monomer
When a non-crosslinkable non-crosslinkable monomer other than (2) and a crosslinkable monomer are subjected to suspension polymerization, when the polymerization rate is less than 90%, the hydrophobic monomer (1) and the hydrophilic monomer The liquid crystal display spacer according to claim 1, which is obtained by adding and copolymerizing the monomer (2) simultaneously or separately together with a polymerization initiator. 5. Fine particles having at least a hydrophobic group represented by the general formula (1) and a hydrophilic group represented by the general formula (2) on at least the surface thereof are converted into hydrophobic monomers (1) and (2). Hydrophilic monomer
When the radical-polymerizable polymerizable monomer other than (2) is subjected to suspension polymerization, both a hydrophobic monomer (1) and a hydrophilic monomer (2) are used as a dispersion stabilizer as a component. Or a hydrophobic monomer (1) and a hydrophilic monomer (2)
With either one of the hydrophobic monomer (1) and the hydrophilic monomer
In suspension polymerization of a radically polymerizable polymerizable monomer other than (2), the other of the hydrophobic monomer (1) and the hydrophilic monomer (2) is used as a dispersion stabilizer as a component. The liquid crystal display spacer according to claim 1, which is obtained by using a copolymer represented by the following formula: 6. A fine particle having a hydrophobic group represented by the general formula (1) and a hydrophilic group represented by the general formula (2) on at least the surface thereof, comprising: a hydrophobic monomer (1); Hydrophilic monomer
(2) Non-crosslinkable monomer other than the crosslinked polymer fine particles comprising a copolymer of a crosslinkable monomer, a hydrophobic monomer (1)
And after impregnating the hydrophilic monomer (2) and the crosslinkable monomer and the polymerization initiator, further polymerize, or
Crosslinking comprising a copolymer of either (1) or the hydrophilic monomer (2) with a polymerizable monomer other than the hydrophobic monomer (1) and the hydrophilic monomer (2) The polymer fine particles are obtained by impregnating the other of the hydrophobic monomer (1) and the hydrophilic monomer (2), the crosslinkable monomer and the polymerization initiator, and then further polymerizing. The liquid crystal display spacer according to claim 1.