JPH11142860A - Liquid crystal display element spacer and liquid crystal display element - Google Patents

Abstract

(57) Abstract: A liquid crystal display element spacer that does not adversely affect the liquid crystal, such as disturbing the alignment of the liquid crystal, and does not move in a liquid crystal cell, and has high-quality display performance. Provided is a liquid crystal display device. A plastic microsphere obtained by polymerizing a monomer having an ethylenically unsaturated group, wherein 5% by weight or more of the monomer having an ethylenically unsaturated group is 2 or more ethylene atoms. A compound having a functional group represented by the following general formula (I) or a compound having the following general formula (I) on the surface of a plastic microsphere, which is a monomer having an unsaturated group;
A spacer for a liquid crystal display device obtained by reacting or attaching a compound having a functional group represented by I).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a spacer for a liquid crystal display element capable of obtaining a liquid crystal display element having high quality display performance, and a liquid crystal display element using the same.

[0002]

2. Description of the Related Art In general, in a liquid crystal display device, a transparent electrode substrate on which an alignment layer is formed is disposed to face a predetermined gap via a spacer, the periphery is sealed, and liquid crystal is injected into the gap.
Manufactured by sealing the inlet. The spacer is used to keep the gap between the transparent electrode substrates constant, and in order to obtain a liquid crystal display element having uniform and high-quality display performance without display unevenness, in the liquid crystal, It is desirable that the compound exists without adversely affecting the liquid crystal and does not move in the liquid crystal cell.

In such a liquid crystal display device, "discretion" or "light" occurs between or near spacers due to the reason that the spacers move in the liquid crystal cell due to electric or physical impact or the like. Missing"
It is known that the liquid crystal display device has an abnormal alignment of the liquid crystal, which is referred to as the above. In particular, this phenomenon is likely to occur in a super twisted nematic (STN) type liquid crystal display device.

In this case, if the liquid crystal molecules are provided with sufficient vertical alignment at the interface between the liquid crystal molecules and the spacers and the movement of the spacers in the liquid crystal cell can be prevented, the above-mentioned alignment abnormality is prevented. As a result, it is possible to dramatically improve the display quality of the liquid crystal display device. At the interface between the liquid crystal molecules and the spacer,
Several methods have been proposed for imparting vertical alignment to liquid crystal molecules.

For example, JP-A-64-59212 and JP-A-2-297523 disclose that a liquid crystal molecule is vertically aligned by treating the surface of an inorganic spacer such as glass fiber, silica or alumina with an organic silane compound. A method has been proposed. JP-A-6-11719 proposes a method of vertically aligning liquid crystal molecules by forming an organic silane compound film on the surface of plastic microspheres.

However, in such a conventional technique, it is possible to prevent the alignment abnormality by giving the liquid crystal molecules vertical alignment, but it is not possible to eliminate the alignment abnormality caused by the movement of the spacer. However, a liquid crystal display device having high quality display performance could not be obtained.

[0007]

SUMMARY OF THE INVENTION In view of the above, the present invention provides a spacer for a liquid crystal display element which does not adversely affect the liquid crystal, such as disturbing the alignment of the liquid crystal, and which does not move in a liquid crystal cell. It is another object of the present invention to provide a liquid crystal display device having high quality display performance.

[0008]

SUMMARY OF THE INVENTION The present invention is a plastic microsphere obtained by polymerizing a monomer having an ethylenically unsaturated group. A compound having a functional group represented by the following general formula (I) on the surface of plastic microspheres, which is a monomer having two or more ethylenically unsaturated groups by weight or more;

[0009]

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(Wherein, R ¹ represents an alkyl group having 3 to 21 carbon atoms, and m and n each independently represent an integer of 1 to 30) or the following general formula (II) Compounds having the functional groups represented;

[0011]

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(Wherein, R ² represents an alkyl group having 4 to 22 carbon atoms, and p and q independently represent an integer of 1 to 30). This is a display element spacer. Hereinafter, the present invention will be described in detail.

The plastic microspheres used in the present invention are obtained by polymerizing a monomer having an ethylenically unsaturated group. 5% by weight or more of the monomers having an ethylenically unsaturated group is a monomer having two or more ethylenically unsaturated groups. When the amount of the monomer having two or more ethylenically unsaturated groups is less than 5% by weight, the strength for maintaining the gap is reduced, and the function as a spacer is not achieved.

As the monomer having two or more ethylenically unsaturated groups, for example, the following monomers and the like can be used. Tetramethylolmethanetetra (meth) acrylate, tetramethylolmethanetri (meth) acrylate, tetramethylolmethanedi (meth) acrylate,
Y methylolalkyl Z (meth) acrylate such as trimethylolpropane tri (meth) acrylate, dipentaerythritol hexa (meth) acrylate, dipentaerythritol penta (meth) acrylate, glycerol tri (meth) acrylate, glycerol di (meth) acrylate (However, Y and Z represent an integer satisfying the condition of Y ≧ Z ≧ 2);

Polyoxyalkylene glycol di (meth) acrylates such as polypropylene glycol di (meth) acrylate and polypropylene glycol di (meth) acrylate; triallyl (iso) cyanurate, triallyl trimellitate; divinylbenzene, diallyl phthalate, diallyl acrylamide And the like. These may be used alone or in combination of two or more.

The plastic fine sphere contains the monomer having two or more ethylenically unsaturated groups as a constituent component in an amount of 5% by weight or more. Only a monomer may be used as a constituent.
When the monomer having an ethylenically unsaturated group contains a monomer having another ethylenically unsaturated group,
For example, styrene-based monomers such as styrene and α-methylstyrene; and (meth) acrylates such as methyl (meth) acrylate can be used. These may be used alone or in combination of two or more.

The plastic microspheres can be obtained by polymerizing the monomer having an ethylenically unsaturated group by a known method. As the polymerization method, for example,
Examples include a method of performing suspension polymerization in the presence of a radical polymerization initiator. The plastic microspheres preferably have an average particle size of 0.1 to 100 μm, more preferably 1 to 100 μm. The plastic microspheres may be colorless and transparent, or may be colored by an appropriate technique as needed.

The spacer for a liquid crystal display element according to the present invention, on the surface of the plastic microsphere, has the general formula (I)
Or a compound having a functional group represented by the general formula (I)
It is obtained by reacting or attaching a compound having a functional group represented by I) by adsorption or the like.

In the compound having a functional group represented by the general formula (I), R ¹ is an alkyl group having 3 to 21 carbon atoms. When the number of carbon atoms is less than 3, the liquid crystal molecules cannot have sufficient vertical alignment. When the number of carbon atoms is more than 21, the liquid crystal molecules are easily charged and the handling property as fine powder deteriorates. . Preferably, it is a straight-chain alkyl group having 7 to 17 carbon atoms.

In the compound having a functional group represented by the above general formula (I), m and n represent the number of moles of ethylene oxide chain added and are each independently an integer of 1 to 30.
When m or n exceeds 30, the vertical orientation as a whole decreases, so that the range is limited to the above range.

A typical example of the compound having a functional group represented by the above general formula (I) is diethanolamide stearic acid represented by the following formula (III).

[0022]

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The stearic acid diethanolamide represented by the above formula (III) can be easily synthesized from stearic acid chloride and diethanolamine. Generally, the following general formula (IV);

[0024]

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An acid chloride represented by the following general formula (V):

[0026]

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By reacting with a diolamine represented by the formula (1), a compound having a functional group represented by the above formula (I) can be easily obtained. The compounds having a functional group represented by the general formula (I) may be used alone or in combination of two or more.

In the compound having a functional group represented by the general formula (II), R ² is an alkyl group having 4 to 22 carbon atoms. If the number of carbon atoms is less than 4, the liquid crystal molecules cannot have sufficient vertical alignment. If the number of carbon atoms exceeds 22, the liquid crystal molecules are easily charged and the handling properties as fine powder deteriorate, so that the range is limited to the above range. . Preferably,
It is a straight-chain alkyl group having 8 to 18 carbon atoms.

In the compound having a functional group represented by the general formula (II), p and q represent the number of moles of ethylene oxide chain added, and are each independently an integer of 1 to 30. When p or q exceeds 30, the vertical orientation as a whole decreases, so that it is limited to the above range.

Typical examples of the compound having a functional group represented by the above general formula (II) include N-stearyldiethanolamine represented by the following formula (VI).

[0031]

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The N-stearyldiethanolamine represented by the formula (VI) can be easily synthesized from ethylene oxide and stearylamine. Generally, the following general formula (VII):

[0033]

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By reacting the alkylamine represented by the formula with ethylene oxide, a compound having a functional group represented by the above general formula (II) can be easily obtained.

The compound having a functional group represented by the general formula (II) may be used alone or in combination of two or more. In the present invention, a compound having a functional group represented by the general formula (I) and a compound having a functional group represented by the general formula (II) can be used in combination.

The amount of the compound having the functional group represented by the general formula (I) or the compound having the functional group represented by the general formula (II) is determined based on the amount of the plastic microsphere surface. Is difficult to quantify, and there is no particular limitation as long as the effects of the present invention are exhibited.

The spacer for a liquid crystal display element of the present invention is obtained, for example, by the following method. In the following method, stearic acid diethanolamide represented by the above formula (III), which is a compound having a functional group represented by the above general formula (I), or a compound represented by the above general formula (II) The case where N-stearyldiethanolamine represented by the above formula (VI), which is a compound having a functional group, is used will be described.

As a first method, there is a method of reacting the above-mentioned plastic microspheres with a polyfunctional isocyanate compound interposed. Also, as a second method,
There is a method in which a monomer having at least one isocyanate group and an ethylenically unsaturated group is reacted in advance, and then the graft polymerization is performed on the surface of the plastic microspheres. The present invention is not limited to the above two methods.

In the first method, specifically, for example,
In a suitable dispersion medium, the plastic microspheres and an excess amount of a polyfunctional isocyanate compound such as toluene diisocyanate are reacted under an appropriate catalyst, and then a separately prepared stearin represented by the above formula (II) is prepared. The reaction can be carried out by adding a solution of acid diethanolamide or a solution of N-stearyldiethanolamine represented by the above formula (IV) and reacting at an appropriate temperature.

The dispersion medium preferably has no active hydrogen, and examples thereof include aromatic solvents such as toluene and xylene; hexane, heptane, octane, nonane, and the like.
Aliphatic solvents such as decane; ether solvents such as tetrahydrofuran;

Examples of the polyfunctional isocyanate compound include toluene diisocyanate, xylene diisocyanate, chlorophenylene diisocyanate, hexamethylene diisocyanate, isophorone diisocyanate, and tetraisocyanate silane.

The second method is, for example, specifically, for example,
First, the diethanolamide stearate represented by the above formula (II) is reacted in advance with a monomer having at least one isocyanate group such as methacryloyloxyethyl isocyanate and an ethylenically unsaturated group, and (VIII);

[0043]

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A monomer having a functional group according to the present invention represented by the following formula is synthesized, or at least one of N-stearyldiethanolamine represented by the above formula (IV) and methacryloyloxyethyl isocyanate Is reacted with a monomer having an ethylenically unsaturated group of the following formula (IX);

[0045]

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A monomer having a functional group according to the present invention represented by the following formula is synthesized, and then a monomer represented by the above formula (VIII) or a monomer represented by the above formula (IX) is prepared. It can be carried out by graft-polymerizing the body onto the surface of the plastic microspheres in a suitable dispersion medium under a suitable catalyst and at a suitable temperature.

The present invention 2 is a liquid crystal display device using the liquid crystal display device spacer of the present invention 1. Invention 2
Is manufactured by an ordinary method using the liquid crystal display element spacer of the first invention.

[0048]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

Example 1 Plastic microspheres obtained by polymerizing 30 parts by weight of tetramethylol methane triacrylate and 70 parts by weight of divinylbenzene (average particle size: 6.02 μm, standard deviation:
0.29 μm) 0.1 g of di-n-butyltin dilaurate was dissolved in a dispersion medium in which 10 g was dispersed in 50 mL of toluene with stirring. A solution prepared by dissolving 5 g of toluene diisocyanate in 30 mL of toluene was added dropwise to this dispersion with stirring, followed by stirring in a water bath at 80 ° C. for 30 minutes.

Next, stearic acid diethanolamide 1
A solution of 0.5 g dissolved in 50 mL of toluene was added dropwise with stirring, and then stirring was continued for 3 hours in a water bath at 80 ° C. After 3 hours, the plastic microspheres after the reaction were thoroughly washed with toluene and collected by filtration. The collected plastic fine spheres were dried in a dryer at 140 ° C. for 1 hour to obtain a liquid crystal display element spacer. Using the obtained spacer for a liquid crystal display element, evaluation was performed by the following method, and the results are shown in Table 1.

(1) Spacer movement A commercially available polyimide alignment film was arranged and rubbed.
After the obtained spacers were sprayed on a glass substrate of cm × 15 cm at a rate of about 200 / mm ² , the other glass substrate treated in the same manner as above was rubbed in a rubbing direction (twist angle) of 240 °. Were arranged so as to face each other. The periphery of the glass substrate was sealed using a commercially available sealant, and heated and pressed to form an empty cell. A commercially available STN type liquid crystal was injected into this empty cell to produce a liquid crystal cell. An optical microscope was used to observe the presence or absence of the spacer movement after hitting the approximate center of the liquid crystal cell 30 times with a “Katsunuma percussion device”.

(2) Abnormal liquid crystal alignment An STN-type liquid crystal display element was manufactured using the obtained spacer by a conventional method, and the alignment state of the liquid crystal after annealing at 90 ° C. for 1 hour was observed. Also, using this liquid crystal display element, the presence or absence of spacer movement after applying an AC voltage of 80 V for 10 seconds was evaluated.

Example 2 The same operation as in Example 1 was carried out except that 8.1 g of lauric acid diethanolamide was used instead of 10.5 g of stearic acid diethanolamide to obtain a spacer for a liquid crystal display device. Evaluation was performed in the same manner as in Example 1 using the obtained liquid crystal display element spacer, and the results are shown in Table 1.

Example 3 6.6 g of diethanolamide stearate and 0.05 g of di-n-butyltin dilaurate in 30 mL of toluene
Was separately added dropwise with stirring to a solution of 5.0 g of methacryloyloxyethyl isocyanate in 30 mL of toluene. While stirring this solution,
After reacting in a water bath at 80 ° C. for 3 hours, toluene was distilled off to obtain a monomer having a functional group according to the present invention.

Next, the plastic microspheres obtained in Example 1 (average particle size: 6.02 μm, standard deviation: 0.29 μm)
m) 10 g of distilled water / ethanol (100 mL / 100
mL) 0.6 g of potassium persulfate was dissolved in the dispersion dispersed in the mixture. To this dispersion, with stirring at room temperature,
The obtained monomer was dispersed, and stirring was further continued in a water bath at 60 ° C. for 5 hours.

The dispersion after the reaction was allowed to stand, and the plastic microspheres were allowed to settle. The supernatant was removed by decantation, washed well with ethanol, and collected by filtration. The collected plastic fine spheres were dried in a dryer at 140 ° C. for 1 hour to obtain a liquid crystal display element spacer. Evaluation was performed in the same manner as in Example 1 using the obtained liquid crystal display element spacer, and the results are shown in Table 1.

Comparative Example 1 The same operation as in Example 1 was carried out except that 4.6 g of propionic acid diethanolamide having two carbon atoms in the alkyl group R was used instead of 10.5 g of stearic acid diethanolamide. A display element spacer was obtained. Evaluation was performed in the same manner as in Example 1 using the obtained liquid crystal display element spacer, and the results are shown in Table 1.

[0058]

[Table 1]

Example 4 The plastic fine spheres obtained in Example 1 (average particle size: 6.
0.1 g of di-n-butyltin dilaurate was dissolved with stirring in a dispersion medium in which 10 g of (02 μm, standard deviation: 0.29 μm) was dispersed in 50 mL of toluene. A solution prepared by dissolving 5 g of toluene diisocyanate in 30 mL of toluene was added dropwise to this dispersion with stirring, followed by stirring in a water bath at 80 ° C. for 30 minutes.

Next, a solution prepared by dissolving 10.3 g of N-stearyldiethanolamine in 50 mL of toluene was added dropwise with stirring, and stirring was continued in a water bath at 80 ° C. for 3 hours. After 3 hours, the plastic microspheres after the reaction were thoroughly washed with toluene and collected by filtration. The collected plastic fine spheres were dried in a dryer at 140 ° C. for 1 hour to obtain a liquid crystal display element spacer. Using the obtained spacer for a liquid crystal display element, evaluation was performed in the same manner as in Example 1, and the results are shown in Table 2.

Example 5 A liquid crystal display element spacer was obtained in the same manner as in Example 4 except that 6.3 g of N-octyldiethanolamine was used instead of 10.3 g of N-stearyldiethanolamine. Using the obtained spacer for a liquid crystal display element, evaluation was performed in the same manner as in Example 1, and the results are shown in Table 2.

Example 6 A liquid crystal display was performed in the same manner as in Example 4 except that 2.7 g of N-hexyldiethanolamine and 3.9 g of N-dodecyldiethanolamine were used instead of 10.3 g of N-stearyldiethanolamine. An element spacer was obtained. Using the obtained spacer for a liquid crystal display element, evaluation was performed in the same manner as in Example 1, and the results are shown in Table 2.

Example 7 3.7 g of N-octyldiethanolamine and 0.05 g of di-n-butyltin dilaurate in 30 mL of toluene
Was separately added dropwise with stirring to a solution of 5.0 g of methacryloyloxyethyl isocyanate in 30 mL of toluene. While stirring this solution,
After reacting in a water bath at 80 ° C. for 3 hours, toluene was distilled off to obtain a monomer having a functional group according to the present invention.

Next, the plastic microspheres obtained in Example 1 (average particle size: 6.02 μm, standard deviation: 0.29 μm)
m) 10 g of distilled water / ethanol (100 mL / 100
mL) 0.6 g of potassium persulfate was dissolved in the dispersion dispersed in the mixture. To this dispersion, with stirring at room temperature,
The obtained monomer was dispersed, and stirring was further continued in a water bath at 60 ° C. for 5 hours.

The dispersion after the reaction was allowed to stand to settle the plastic microspheres, the supernatant was removed by decantation, and the collected plastic microspheres were dried in a dryer at 140 ° C. for 1 hour. A spacer for a liquid crystal display element was obtained. Using the obtained spacer for a liquid crystal display element, evaluation was performed in the same manner as in Example 1, and the results are shown in Table 2.

Comparative Example 2 The same operation as in Example 4 was carried out, except that instead of 10.3 g of N-stearyldiethanolamine, 4.2 g of N-propyldiethanolamine having 3 carbon atoms in the alkyl group R was used. A display element spacer was obtained. Using the obtained spacer for a liquid crystal display element, evaluation was performed in the same manner as in Example 1, and the results are shown in Table 2.

[0067]

[Table 2]

[0068]

Since the spacer for a liquid crystal display element of the present invention is as described above, it does not adversely affect the liquid crystal such as disturbing the alignment of the liquid crystal and does not move in the liquid crystal cell. Thus, a liquid crystal display device having high quality display performance can be obtained.

Claims (3)

[Claims] 1. Plastic microspheres obtained by polymerizing a monomer having an ethylenically unsaturated group, wherein at least 5% by weight of the monomer having an ethylenically unsaturated group is at least 2 A compound having a functional group represented by the following general formula (I) on the surface of plastic microspheres, which is a monomer having an ethylenically unsaturated group; (Wherein, R ¹ represents an alkyl group having 3 to 21 carbon atoms;
m and n each independently represent an integer of 1 to 30. Or a compound having a functional group represented by the following general formula (II): (Wherein, R ² represents an alkyl group having 4 to 22 carbon atoms;
p and q independently represent an integer of 1 to 30. A spacer for a liquid crystal display element obtained by reacting or adhering a). 2. A monomer having two or more ethylenically unsaturated groups is Y methylolalkyl Z (meth) acrylate (where Y and Z represent integers satisfying a condition of Y ≧ Z ≧ 2). , Polyoxyalkylene glycol di (meth) acrylate, triallyl (iso) cyanurate,
The spacer for a liquid crystal display device according to claim 1, wherein the spacer is at least one selected from the group consisting of triallyl trimellitate, divinylbenzene, diallyl phthalate, and diallyl acrylamide. 3. A liquid crystal display device, wherein the liquid crystal display device spacer according to claim 1 or 2 is used.