JP2000273187A - Graded composite particle and its preparation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a graded composite particle and a graded composite particle which is prepared by calcining this particle and has an improved breaking strength without deteriorating the 10% compressive modulus and recovery, and to provide preparation process therefor. SOLUTION: A graded composite particle has two or more polyorganosiloxanes having different organic groups, wherein the composition gradually or continuously changes from the center towards the surface of the particle. A graded composite particle is prepared by calcining this particle and has desirable physical properties. In a preparation process of the graded composite particle having desirable physical properties, two or more organosilicon compounds having from 1 to 3 non-hydrolyzable groups and from 3 to 1 alkoxyl group are selected, hydrolyzed and condensed to form a graded composite particle, which is then dried and calcined at from 200 to 700 deg.C.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel gradient composite particle, a method for producing the same, and a spacer for a liquid crystal display comprising the gradient composite particle. More specifically, the present invention relates to a gradient silica composite particle whose composition changes from the center toward the surface, it is easy to control the 10% compression elastic modulus obtained by firing the same, TECHNICAL FIELD The present invention relates to monodisperse gradient composite particles having improved breaking strength without impairing the recovery rate and the recovery ratio, a method for efficiently producing the same, and a spacer for a liquid crystal display device comprising the fired gradient composite particles.

[0002]

2. Description of the Related Art Conventionally, monodispersed silica particles having a particle size distribution (hereinafter sometimes simply referred to as monodispersed silica particles)
It is known that it is useful as various kinds of fillers and ceramic raw materials, but in particular, recently, its use as a spacer of a liquid crystal display device has attracted attention and has begun to be used.

Conventionally, glass fiber chips or fine particles of synthetic resin have been used for spacers of liquid crystal display devices. However, glass fiber chips have excellent fiber diameter accuracy, but their lengths vary widely, and those that are too long can be visually observed and degrade the image quality. There is a possibility that the formed alignment film, protective film, color filter, electric element or the like may be damaged. In addition, fine particles of synthetic resin have poor particle size accuracy, and may not be able to satisfy the performance required as a spacer for a liquid crystal display device. Therefore, when a higher gap accuracy is required, an alignment film or a protective film, a color filter or an IT film formed on a substrate having a good particle size accuracy and a spherical shape.
A material that does not damage the electric element such as an O conductive film is required.

To satisfy these requirements, silica particles obtained by hydrolyzing and polycondensing alkoxysilane have been proposed. The silica particles are (1) high in purity, little affected by the eluted components on the liquid crystal, (2) have good particle size accuracy, and the following formula: CV (%) = [standard deviation of fine particle diameter (μm)] / [average Particle size (μm)] × 100 has an advantage that the CV value (coefficient of variation) obtained can be 10% or less.

However, silica particles are poorly deformable, and because of their hardness, they are sunk into a color filter, causing poor alignment of liquid crystals or having a large difference in thermal expansion coefficient from liquid crystals, resulting in low temperatures. Thus, the liquid crystal device cannot follow the contraction of the liquid crystal, causing air bubbles in the liquid crystal element, which has a problem of impairing the display function. Thus, recently, silica particles having an organic component and having an intermediate hardness between resin particles and silica particles and having a thermal expansion coefficient closer to that of a liquid crystal than silica particles have been developed.

Since silica particles having an organic component obtained by hydrolysis and polycondensation of an alkylalkoxysilane have the above-mentioned advantages, a number of production methods have been proposed. For example, a method of producing polymethylsilsesquisiloxane fine particles using methyltrimethoxysilane as a raw material has been proposed (Japanese Patent Publication No. 4-70335).
No.). However, in this method, it is difficult to obtain monodispersed particles having a controlled hardness and a good recovery rate from the technical contents. Further, an organosilicon compound represented by the general formula R _m Si (OR ') _4-m (wherein R and R' each represent a specific organic group, and m is an integer of 0 to 3). (Patent No. 2698541) discloses a method for producing a liquid crystal cell spacer composed of particles having a specific compression modulus by subjecting particles obtained by hydrolysis and condensation to heat treatment. In this technique, the compression elastic modulus of the spacer is controlled by decomposing a part of the organic groups present inside the particles in the heat treatment step and controlling the degree of decomposition. However, in this case, there is a problem that voids are generated in the organic group portion inside the thermally decomposed particles, and the breaking strength of the obtained liquid crystal cell spacer is inevitably reduced.

Therefore, a tetrafunctional alkoxide such as tetraethoxysilane is converted to a trifunctional alkoxide such as methyltrimethoxysilane.
Many studies have been made to improve the breaking strength by compounding with a functional alkoxide.However, in this case, it is difficult to obtain uniformly compounded particles within the particles due to different hydrolysis and condensation characteristics. An inflection point is often found in the compression curve, and there is a problem that having such a point where the elastic modulus changes suddenly is not preferable as a spacer for a liquid crystal cell.

Further, heat treatment is performed as a drying step.
A technique for producing particles having a compression elastic modulus in a specific range without decomposing organic groups has been disclosed (JP-A-8-81).
561, JP-A-9-59384). However, in this case, the compression modulus is determined by the particle component, and particles having a compression modulus in a specific range can be produced,
It is difficult to arbitrarily control the compression modulus within the range of the compression modulus. The reason that the compression modulus is arbitrarily controlled is that the hardness of the color filters and protective films, etc., existing in the liquid crystal substrate varies among liquid crystal display element manufacturers, and the required hardness is currently different. And to respond to it.

On the other hand, as can be said for all of these particles, when the tetrafunctional alkoxide is compounded in a uniform state in order to improve the breaking strength, the breaking strength is improved as compared with the non-composited particles. In general, the 10% compression modulus changes with the improvement of the breaking strength, and the 10% compression modulus also increases. In addition, the softness of the siloxane skeleton is reduced, so that the recovery rate is inevitably reduced.

[0010] As described above, the conventional silica-based particles have problems, respectively, and have a monodisperse property, and it is easy to control the 10% compression modulus. At the same time, silica particles having improved breaking strength without impairing the recovery rate have not been found yet.

[0011]

SUMMARY OF THE INVENTION Under such circumstances, the present invention makes it easy to control the 10% compression elastic modulus, and without impairing the 10% compression elastic modulus and the recovery rate.
An object of the present invention is to provide a monodisperse spherical silica-based particle having improved breaking strength, a method for efficiently producing the same, and a spacer for a liquid crystal display device comprising the particle.

[0012]

Means for Solving the Problems The present inventors have conducted intensive studies to achieve the above object, and as a result, (1) 10%
In order to arbitrarily control the compression modulus, although there is a problem that the fracture strength is reduced, it is advantageous to heat-treat the particles obtained by hydrolyzing and condensing the organosilicon compound, and to change the heat-treatment conditions at that time. (2) The initial compressive modulus for a load represented by 10% compressive modulus or the like is greatly affected by the physical properties near the surface of the particle, while the breaking strength is mainly determined from the center of the particle to the surface. It is considered to be the tensile strength towards the side, and therefore to increase the breaking strength, it is particularly advantageous to increase the particle center. Therefore, it is desirable that the central part of the particle has high strength and the surface part is a soft particle. (3) However, in the case of the particle having the above-mentioned property (2), there is a large difference in hardness between the particle central part and the surface part. In general, stress cannot be dispersed throughout the particles at the interface between the materials having the two different physical properties, and the stress concentrates to cause cracks, conversely causing a decrease in fracture strength, In the initial compression curve, which is a curve showing the compression displacement with respect to the load, an inflection point is observed near the interface, which may hinder maintaining the gap of the liquid crystal cell uniformly. In terms of resilience, attention was paid to the possibility that a problem might occur for the same reason.

The inventors of the present invention have further studied based on these attentions, and if the hardness is gradually changed from the center of the particles toward the surface, the above-mentioned problem (3) can be solved. In addition, such a gradient particle is selected from two or more kinds of organosilicon compounds having 1 to 3 non-hydrolyzable groups and 3 to 1 alkoxyl groups bonded to a silicon atom, After decomposing and condensing, to form spherical composite particles having two or more polyorganosiloxanes and having a composition that changes stepwise or continuously from the particle center toward the surface direction, It has been found that it can be obtained by firing at a temperature.

The present invention has been completed based on such findings. That is, the present invention is characterized in that (1) it has two or more kinds of polyorganosiloxanes having different organic groups, and the composition changes stepwise or continuously from the particle center toward the surface. (2) two or more kinds of polyorganosiloxanes having different organic groups,
Gradient composite particles (hereinafter, referred to as gradient composite particles II), which are obtained by firing spherical composite particles whose composition changes stepwise or continuously from the particle center toward the surface. And (3) a spacer for a liquid crystal display device comprising the inclined composite particles II.

According to the present invention, the gradient composite particles II are as follows:
1 to 3 non-hydrolysable groups bonded to a silicon atom and 3 to
By selecting two or more kinds from organosilicon compounds having one alkoxyl group, and hydrolyzing and condensing,
After forming spherical composite particles having two or more kinds of polyorganosiloxanes and having a composition that changes stepwise or continuously from the particle center toward the surface, drying treatment is performed,
Next, it can be manufactured by firing at a temperature of 200 to 700 ° C.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION The gradient composite particles I of the present invention are substantially spherical composite silica particles having two or more kinds of polyorganosiloxanes having different organic groups and having a surface extending from the center of the particle to the surface. A spherical composite particle whose composition changes stepwise or continuously toward the direction, and a gradient composite particle
II is obtained by firing these particles.

The properties of the gradient composite particles II are 10
% Compression modulus (X) is 19.6 GPa (2000 kgf
/ Mm ² ) or less, it is essential that the breaking strength (Y) satisfies the relationship of Y (GPa) ≧ 0.13X−0.196 and that the recovery rate is 90% or more. If any one of the 10% compression modulus, the breaking strength, and the recovery rate deviates from the above range, the performance as a spacer for a liquid crystal display device may not be sufficiently satisfied. From the viewpoint of the performance of the spacer for a liquid crystal device, in particular, the 10% compression elastic modulus is 3 to 15 GPa (300 to 15 GPa).
The range is preferably 1500 kgf / mm ² , more preferably 5 to 10 GPa (500 to 1000 kgf / m ² ).
m ² ) is preferred. On the other hand, the breaking strength is 500MP
a (50 kgf / mm ² ) or more is preferable.

The above 10% compression elastic modulus, breaking strength and recovery rate were measured using a micro compression tester (MCTE manufactured by Shimadzu Corporation).
-200) using the following method. (1) 10% compression elastic modulus (n = 10) Particles are scattered on a sample table by a micro compression tester (MCTE-200 manufactured by Shimadzu Corporation), and one sample particle among them is fixed in the center direction of the particle. A load was applied at a load speed of, and the load-compression displacement was measured, and the load at the time of 10% displacement of the particle diameter was determined. The load, the compression displacement of the particles, and the particle diameter were substituted into the following equation to calculate a 10% compression modulus. The load speed was 0.284 mN / sec (0.029 gf / sec)
I went in. E = [3 × P ₁₀ × (1-K ² )] / [2 ^0.5 × S ^1.5 × R
^1.5] [where, E is the compression modulus (MPa), P ₁₀ is the compressive load (N), Poisson's ratio and K particles (constant 0.38), S is the compression displacement (mm), R is the particle radius ( mm). ]

(2) Breaking strength (n = 10) Using the above measuring device, a compressive breaking load was similarly obtained for one sample particle, and the breaking strength was calculated by the following equation. The load speed was 2.65 mN / sec (0.27 gf / sec).
Seconds). St (MPa) = 2.8P / πd ² [where P is the compressive breaking strength (N) and d is the particle size (mm) of the sample. ]

(3) Recovery rate (n = 10) Particles 1 similarly dispersed on a sample stage using the above-mentioned measuring instrument
The reversal load value (1.96 m
N = 0.2 gf), and then the load was gradually reduced to the origin load value (0.098 mN = 0.01 gf).
During this time the load - compression displacement is measured, the displacement from the origin load value to the reversing load value and L _1, from the origin load value, the displacement to the origin for the load value after the reversal load Johnny and L _2, The recovery rate was determined by substituting into the following equation. The load speed at this time was 1.42 mN / sec (0.145 gf / sec). Recovery rate (%) = [(L ₁ −L ₂ ) / L ₁ ] × 100

The inclined composite particles II of the present invention preferably have no inflection point in the initial compression curve showing the compression displacement with respect to the load from the viewpoint of the performance of the spacer for a liquid crystal display device.

Further, the gradient composite particles I and II of the present invention are:
Average particle size is usually 0.5 to 15 μm, preferably 1 to 10
μm, and the coefficient of variation (CV value) of the particle size distribution is
Usually, it is 3.0% or less, and is a substantially spherical monodisperse particle.

The gradient composite particles II of the present invention are obtained by calcining particles having two or more kinds of polyorganosiloxanes having different organic groups, and the polyorganosiloxanes are thermally decomposed. It is preferable to use two types having different temperatures and a difference in thermal decomposition temperature of 50 ° C. or more. The polyorganosiloxane having a low thermal decomposition temperature of the organic component is present so as to increase toward the center, and the polyorganosiloxane having a high thermal decomposition temperature of the organic component is present so as to increase toward the surface side. Those obtained by firing spherical composite particles are particularly suitable.

The sintering of the spherical composite particles is generally carried out at 200 to
The reaction is performed at a temperature in the range of 700 ° C., but as described above, when only two kinds of polyorganosiloxanes are used, the organic component has a lower thermal decomposition temperature than the polyorganosiloxane and has a higher organic decomposition temperature. It is preferable to perform the reaction at a temperature lower than the thermal decomposition temperature of the polyorganosiloxane having a high thermal decomposition temperature.

Further, in the gradient composite particles II of the present invention, in particular, the polyorganosiloxane having a low thermal decomposition temperature of the organic component is a hydrolysis condensate of vinyltrimethoxysilane, and It is preferable that the polyorganosiloxane having a high molecular weight is a hydrolysis condensate of methyltrimethoxysilane. A single particle made of polyvinylsilsesquisiloxane (PVSO), which is a hydrolysis condensate of vinyltrimethoxysilane, and a single particle made of polymethylsilsesquisiloxane (PMSO), which is a hydrolysis condensate of methyltrimethoxysilane. When firing under the conditions, the conditions are such that the methyl group of PMSO is not decomposed and the vinyl group of PVSO is decomposed by a certain amount or more.
It is between 70 ° C and 640 ° C. ), PMSO
The particles have a low compression modulus, whereas the PVSO particles have a high compression modulus and high breaking strength, and the difference in temperature conditions is as large as 200 ° C. or more in a nitrogen atmosphere. Therefore, particles in which PMSO and PVSO are gradedly compounded inside the particles (particles in which PVSO is present so as to increase toward the center and PMSO is present so as to increase toward the surface side) Is calcined at a temperature in the above range, whereby the gradient composite particles II having desired physical properties can be easily obtained. Further, since the firing temperature range for obtaining particles having desired physical properties is large,
Within the temperature range, particles having an arbitrary 10% compression modulus can be obtained.

Furthermore, the raw materials vinyltrimethoxysilane and methyltrimethoxysilane are easily available,
In addition to being inexpensive and having relatively similar hydrolysis and condensation properties, it also has advantages such as easy synthesis of composite particles. The method for producing the gradient composite particles I and II of the present invention may be any method as long as the gradient composite particles I and II having the above properties can be obtained, and is not particularly limited, but according to the method of the present invention described below, Desired gradient composite particles I and II can be efficiently produced.

In the method of the present invention, as a raw material, 1 to 3 non-hydrolyzable groups bonded to a silicon atom and 3 to 1
Two or more organic silicon compounds having two alkoxyl groups are selected and used. As the organosilicon compound, a compound represented by the general formula (I) R ¹ nSi (OR ² ) _4-n (I) (n is an integer of 1 to 3) can be used.

In the general formula (I), R ¹ is an alkyl group having 1 to 20 carbon atoms, an alkyl group having 1 to 20 carbon atoms having a (meth) acryloyloxy group or an epoxy group, and an alkenyl having 2 to 20 carbon atoms. Group, an aryl group having 6 to 20 carbon atoms or an aralkyl group having 7 to 20 carbon atoms.
Here, the alkyl group having 1 to 20 carbon atoms is preferably an alkyl group having 1 to 10 carbon atoms, and the alkyl group may be any of linear, branched and cyclic. Examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group,
Examples include an ec-butyl group, a tert-butyl group, a pentyl group, a hexyl group, an octyl group, a cyclopentyl group, a cyclohexyl group, and the like. As the alkyl group having 1 to 20 carbon atoms having a (meth) acryloyloxy group or an epoxy group, an alkyl group having 1 to 10 carbon atoms having the above substituent is preferable, and the alkyl group is linear, branched, Any of a ring shape may be sufficient. Examples of the alkyl group having this substituent include a γ-acryloyloxypropyl group, a γ-methacryloyloxypropyl group,
Examples include a glycidoxypropyl group and a 3,4-epoxycyclohexyl group. The alkenyl group having 2 to 20 carbon atoms is preferably an alkenyl group having 2 to 10 carbon atoms, and the alkenyl group may be linear, branched, or cyclic. Examples of this alkenyl group include vinyl, allyl, butenyl, hexenyl,
An octenyl group and the like. The aryl group having 6 to 20 carbon atoms is preferably an aryl group having 6 to 10 carbon atoms, and examples thereof include a phenyl group, a tolyl group, a xylyl group, and a naphthyl group. The aralkyl group having 7 to 20 carbon atoms is preferably an aralkyl group having 7 to 10 carbon atoms, and examples thereof include a benzyl group, a phenethyl group, a phenylpropyl group, and a naphthylmethyl group.

On the other hand, R ² is an alkyl group having 1 to 6 carbon atoms, which may be linear, branched or cyclic, such as methyl, ethyl and n-propyl. Group, isopropyl group, n-butyl group, isobutyl group,
sec-butyl group, tert-butyl group, pentyl group,
Examples include a hexyl group, a cyclopentyl group, and a cyclohexyl group. n is an integer from 1 to 3, when R ¹ are a plurality, each R ¹ may be mutually identical or different and, where OR ² there are a plurality, each OR ² is another May be the same or different.

Examples of the silicon compound represented by the general formula (I) include methyltrimethoxysilane, methyltriethoxysilane, methyltripropoxysilane, methyltriisopropoxysilane, ethyltrimethoxysilane, and ethyltriethoxysilane. , Propyltriethoxysilane, butyltrimethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-acryloyloxypropyltrimethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, dimethyldimethoxysilane, methylphenyldimethoxysilane, and the like.

In the method of the present invention, two or more kinds of these organosilicon compounds are first selected, hydrolyzed and condensed to have two or more kinds of polyorganosiloxanes. A spherical composite particle (gradient composite particle I) whose composition changes stepwise or continuously is formed. At this time, as the two or more kinds of organosilicon compounds, for the gradient composite particles II, the polyorganosiloxane as a hydrolysis condensate has a thermal decomposition temperature of 50%.
It is preferable to select and use two types of organosilicon compounds which differ by at least ° C. Particularly, for the above-mentioned reasons, it is preferable to use vinyltrimethoxysilane and methyltrimethoxysilane.

The spherical composite particles (gradient composite particles I)
For example, (1) contains one or more selected from organosilicon compounds having 1 to 3 non-hydrolyzable groups and 3 to 1 alkoxyl groups bonded to a silicon atom, and each has a composition of Different sets of organosilicon compounds,
Hydrolysis or condensation reaction in two or more steps, or (2) selected from organosilicon compounds having from 1 to 3 non-hydrolyzable groups and from 3 to 1 alkoxyl groups bonded to silicon atoms Using two or more kinds of organosilicon compounds,
The aqueous solution containing the organosilicon compound can be produced by a method of performing a hydrolysis and condensation reaction in one step while continuously changing the composition. According to the above method (1), spherical composite particles having two or more kinds of polyorganosiloxanes and having a composition that changes substantially stepwise from the particle center toward the surface can be obtained. On the other hand, according to the method (2), spherical composite particles having two or more kinds of polyorganosiloxanes and having a composition that changes substantially continuously from the particle center toward the surface can be obtained.

At this time, for the gradient composite particles II, polyorganosiloxane having a low thermal decomposition temperature of the organic component is present so as to increase toward the center, and polyorganosiloxane having a high thermal decomposition temperature of the organic component is present. Is preferably present so as to increase toward the surface side. For example, when vinyltrimethoxysilane and methyltrimethoxysilane are used as raw materials, polyvinylsilsesquisiloxane (PVSO) is present so as to increase toward the center, and polymethylsilsesquisiloxane (PMSO) toward the surface. It is better to make it exist.

First, the hydrolysis and condensation reactions in the method (1) will be described. The organosilicon compound alone or a mixture of two or more thereof is mixed with ammonia and / or ammonia.
Or an aqueous solution containing an amine or a mixed solvent solution of water and an organic solvent (hereinafter, this aqueous solution and the mixed solvent solution may be referred to as an aqueous solution), preferably in a two-layer state without being substantially mixed. While maintaining the reaction at the interface.

The above-mentioned ammonia and amine are catalysts for the hydrolysis and condensation reaction of the organosilicon compound. Here, as the amine, for example, monomethylamine, dimethylamine, monoethylamine, diethylamine, ethylenediamine and the like can be preferably mentioned. This ammonia or amine may be used alone or in combination of two or more kinds, but is less toxic, easy to remove,
Ammonia is preferred because it is inexpensive.

This ammonia or amine is used as an aqueous solution or a mixed solvent solution of water and an organic solvent. Here, the organic solvent is preferably a water-miscible solvent, for example, lower alcohols such as methanol, ethanol, propanol and butanol, acetone, dimethyl ketone, ketones such as methyl ethyl ketone, ethers such as diethyl ether and dipropyl ether. And the like.

The amount of ammonia or amine to be used is not particularly limited, but the pH of the lower aqueous layer before the start of the reaction is adjusted to 7.
It is preferable to select a value in the range of 5 to 11.0. The reaction temperature depends on the kind of the organosilicon compound as the raw material and the like, but is generally selected in the range of 0 to 60 ° C.

Next, after the upper layer substantially disappears, a second stage hydrolysis and condensation reaction is carried out in the same manner as described above using an organosilicon compound having a composition different from that described above or a mixture of two or more thereof. Further, if necessary, the same operation as described above is repeated a desired number of times using an organosilicon compound having a different composition alone or a mixture of two or more kinds.

After the upper layer has disappeared in the last hydrolysis and condensation reaction, ammonia and / or amine are added to the reaction system to ripen it. This aging may be performed at the same temperature as the reaction, or may be performed at a slightly elevated temperature. After the aging, the produced particles are sufficiently washed according to a conventional method, and if necessary, a classification treatment is performed to remove the maximum or minimum particles, followed by a drying treatment. The classification method is not particularly limited, but a wet classification method in which classification is performed by utilizing the fact that the sedimentation speed varies depending on the particle size is preferable. The drying treatment is usually performed at a temperature in a range from normal temperature to 150 ° C.

Next, one example of the hydrolysis and condensation reactions in the above method (2) will be described. First, two or more aqueous solutions containing the above-mentioned organosilicon compound alone or two or more and having different compositions are used. Prepare. These aqueous solutions are then continuously added to the other aqueous solution at the same rate, one after the other, while the last aqueous solution is continuously added to the aforementioned aqueous solution containing ammonia and / or amine at the same rate as above. And dripping. Specifically, it is assumed that, for example, organic silicon compound-containing aqueous solutions having different compositions of (A), (B), (C) and (D) are prepared. In this case, (D) is continuously added to (C) at the same rate, (C) is added to (B), and (B) is added to (A) while (A) is added to ammonia and And / or dropwise into the aqueous solution containing the amine at the same rate as above. After completion of the dropwise addition, the mixture is aged for about 1 to 4 hours to undergo hydrolysis and condensation reactions. The reaction temperature is usually selected in the range of 0 to 60 ° C. Next, ammonia and / or an amine are added to the reaction system, and the mixture is sufficiently aged. This aging may be performed at the same temperature as the reaction, or may be performed at a slightly elevated temperature.

Thereafter, by performing the same operation as in the above (1), desired spherical composite particles (gradient composite particles I) are obtained. According to this method, the composition of the aqueous solution containing the organosilicon compound dropped into the reaction field changes continuously, so that the one obtained by the method (1) has a substantially stepwise gradient structure. In contrast, particles having a substantially continuous gradient structure are obtained. Further, since each organosilicon compound is dissolved in water and used as an aqueous solution, the particle formation is not affected by the difference in dissolution rate with respect to the solvent in the reaction field. Easy to make than.

After obtaining the monodisperse spherical composite particles (gradient composite particles I) in this way, by performing a calcination treatment, the gradient composite particles II are obtained. The firing temperature is
Usually, the temperature is selected in the range of 200 to 700 ° C., but when only two types of polyorganosiloxane are contained in the spherical composite particles, the organic component has a higher thermal decomposition temperature than the polyorganosiloxane having a lower thermal decomposition temperature, and It is preferable to select a temperature within a range lower than the thermal decomposition temperature of the polyorganosiloxane having a high thermal decomposition temperature of the organic component. This firing treatment can be performed in an atmosphere of an inert gas such as nitrogen gas. The firing time depends on the type of the spherical composite particles and the firing temperature, and cannot be unconditionally determined,
Generally, it is about 0.5 to 10 hours.

After the completion of the baking process, a classification process may be performed, if necessary, to remove the coalesced particles by the baking. In this way, monodisperse substantially spherical inclined composite particles II having a 10% compression modulus, a breaking strength and a recovery within a desired range are obtained. Graded composite particles of the present invention II
Is particularly suitable as a spacer for a liquid crystal display device because it has the above properties.

[0044]

EXAMPLES Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples. Example 1 In a 300 ml plastic container, 1 mol /
250 ml of an aqueous solution containing 0.2 ml / liter of aqueous ammonia having a concentration of 1 liter was placed therein, and stirred with a magnetic stirrer at about 60 rpm.
5 g of vinyltrimethoxysilane (VTMS) was slowly added to form a VTMS layer on the upper layer. Then, the mixture was stirred at room temperature until the upper layer completely disappeared.
3.3 g of TMS and methyltrimethoxysilane (MTM
S) A homogeneous mixture with 1.7 g was slowly added, and a mixed solution layer of VTMS and MTMS was formed in the upper layer, and the mixture was stirred until the upper layer completely disappeared. Next, VTMS
A homogeneous mixture of 2.5 g and 2.5 g MTMS, VTMS
A homogeneous mixture of 1.7 g and 3.3 g of MTMS and MTM
S5g is sequentially added in the same manner as described above, and the composition of the silicon compound is gradually changed to form polymethylsilsesquioxane (PMSO) / polyvinylsilsesquioxane (PVSO) particles. Was.

After the last addition of the MTMS layer, stirring was continued for about 2 hours, and then 2 ml of 25% by weight ammonia water was added to solidify the formed particles. Furthermore, after aging overnight, the particles obtained by centrifugation are put into methanol and decanted, and then fine particles formed at the time of solidification of the particles by addition of ammonia water are removed and dried at about 50 ° C. Thus, a dry powder was obtained.

As a result of measuring the particle size distribution and the particle size of the obtained powder with a coal counter, only one large particle size peak was observed, the average particle size was 3.232 μm, and the
It was confirmed that monodisperse particles having a V value of 1.55% were obtained. The measurement of the infrared absorption spectrum of the particles confirmed that the particles were composite particles of PVSO and PMSO. Next, the particles thus obtained were calcined under a nitrogen atmosphere at 280 to 400 ° C. for 2 hours to obtain particles 1-1 to 1-5 having properties shown in Table 1. The 10% compression modulus, breaking strength, and recovery rate were measured using a micro compression tester (MCTE-200 manufactured by Shimadzu Corporation).

[0047]

[Table 1]

For these particles, the relationship between the load and the compression displacement (initial compression curve) was determined. FIG. 1 is a graph showing an example of the particles 1-4. As can be seen from this figure, there was no inflection point and the curve was very smooth. The same was true for the other particles.

Example 2 In a 300 ml plastic container, 1 mol / mol
250 ml of an aqueous solution containing 0.12 ml / liter of aqueous ammonia having a concentration of 1 liter was added thereto, and 12.5 g of VTMS was slowly added thereto while stirring the mixture at about 60 rpm with a magnetic stirrer.
An MS layer was formed. Next, the mixture was stirred at room temperature until the upper layer completely disappeared, and then 12.5 g of MTMS was slowly added to form an MTMS layer on the upper layer. Similarly, the mixture was stirred until the upper layer completely disappeared. Then, Example 1
A dry powder was obtained in the same manner as described above.

As a result of measuring the particle size distribution and the particle size of the obtained powder with a coal counter, only one large particle size peak was observed, the average particle size was 3.852 μm, and the
It was confirmed that monodispersed particles having a V value of 2.07% were obtained. The measurement of the infrared absorption spectrum of the particles confirmed that the particles were composite particles of PVSO and PMSO. Next, the particles thus obtained were baked for 2 hours at each temperature of 330 to 400 ° C. in a nitrogen atmosphere to obtain particles 2-1 to 2-3 having properties shown in Table 2.

[0051]

[Table 2] Also, the initial compression curves for these particles are shown in Example 1.
It was a smooth curve with no inflection point as in the case of.

Example 3 In a 300 ml plastic container, 1 mol / mol
250 ml of an aqueous solution containing 0.1 ml / liter of aqueous ammonia having a concentration of 1 liter was added thereto, and stirred with a magnetic stirrer at about 60 rpm.
4 g of VTMS was slowly added to form a VTMS layer on the upper layer. Next, this was stirred at room temperature until the upper layer completely disappeared, and then 20 g of MTMS was slowly added to form an MTMS layer on the upper layer. Similarly, the mixture was stirred until the upper layer completely disappeared. Thereafter, the same operation as in Example 1 was performed to obtain a dry powder.

As a result of measuring the particle size distribution and the particle size of the obtained powder with a coal counter, only one large particle size peak was observed, the average particle size was 3.485 μm, and the C
It was confirmed that monodispersed particles having a V value of 1.93% were obtained. The measurement of the infrared absorption spectrum of the particles confirmed that the particles were composite particles of PVSO and PMSO. Next, the particles thus obtained were calcined at a temperature of 340 to 500 ° C. for 2 hours in a nitrogen atmosphere to obtain particles 3-1 to 3-5 having properties shown in Table 3.

[0054]

[Table 3] Also, the compression curves of these particles were smooth curves without inflection points as in Example 1.

Example 4 A plastic container having a capacity of 1500 ml was charged with 1000 ml of an aqueous solution containing 0.1 ml / l of 1 mol / l ammonia water.
While stirring this at about 60 rpm with a magnetic stirrer, 25 g of VTMS was slowly added, and the VTMS was added to the upper layer.
Was formed. Next, the mixture was stirred at room temperature until the upper layer completely disappeared, and then 75 g of MTMS was slowly added to form an MTMS layer on the upper layer. Similarly, the mixture was stirred until the upper layer completely disappeared. Thereafter, the same operation as in Example 1 was performed to obtain a dry powder.

As a result of measuring the particle size distribution and the particle size of the obtained powder with a coal counter, only one large particle size peak was observed, and the average particle size was 3.823 μm.
It was confirmed that monodisperse particles having a CV value of 1.67% were obtained. The measurement of the infrared absorption spectrum of the particles confirmed that the particles were composite particles of PVSO and PMSO. Next, the particles thus obtained were calcined at 340 to 500 ° C. for 2 hours in a nitrogen atmosphere to obtain particles 4-1 to 4-5 having properties shown in Table 4.

[0057]

[Table 4] Also, the initial compression curves for these particles are shown in Example 1.
It was a smooth curve with no inflection point as in the case of.

Example 5 The procedure of Example 1 was repeated, except that the addition order of each alkoxysilane was completely reversed, and the content of 1 mol / liter aqueous ammonia solution in the 1 mol / liter aqueous ammonia water solution was changed to 0.4 ml. A dry powder was obtained in the same manner as in Example 1, except that the dry powder was changed to / liter.

As a result of measuring the particle size distribution and the particle size of the obtained powder with a coal counter, only one large particle size peak was observed, the average particle size was 4.609 μm, and the
It was confirmed that monodispersed particles having a V value of 1.49% were obtained. The measurement of the infrared absorption spectrum of the particles confirmed that the particles were composite particles of PVSO and PMSO. Next, the particles thus obtained were calcined under a nitrogen atmosphere at each temperature of 330 to 550 ° C. for 2 hours to obtain particles 5-1 to 5-4 having properties shown in Table 5.

[0060]

[Table 5] Also, the compression curves of these particles were smooth curves without inflection points as in Example 1.

Example 6 A plastic container having a capacity of 300 ml was charged with 225 ml of ion-exchanged water and 25 g of VTMS.
The mixture was stirred until it became uniform to obtain a partially hydrolyzed liquid A. Similarly, 225 ml of ion-exchanged water and 25 g of MTMS were placed in a 300 ml plastic container and stirred until the mixture became uniform to obtain a partially hydrolyzed liquid B.

On the other hand, 500 ml of ion-exchanged water and 1
0.2 ml of aqueous ammonia having a mol / liter concentration was added, and the mixture was stirred until the mixture became uniform to obtain a liquid C. Next, while continuously dropping the above solution B onto the stirring solution A, the solution A is dropped onto the stirring solution C at the same speed. I went over time. After completion of the dropwise addition, the mixture was stirred for about 2.5 hours, and 2 ml of 25% by weight aqueous ammonia was added to solidify the formed particles. Thereafter, the same operation as in Example 1 was performed to obtain a dry powder.

As a result of measuring the particle size distribution and the particle size of the obtained powder with a Coulter counter, only one large particle size peak was observed, and the average particle size was 2.20 μm.
It was confirmed that monodisperse particles having m and CV values of 2.01% were obtained. In addition, according to the infrared absorption spectrum, P
It was found to be composite particles of MSO and PVSO. Next, the particles thus obtained were subjected to a nitrogen atmosphere under nitrogen atmosphere.
Baking was performed at each temperature between 80 to 400 ° C. for 2 hours to obtain particles 6-1 to 6-3 having properties shown in Table 6.

[0064]

[Table 6]

Comparative Example 1 In Example 1, 25 g of only MTMS was used as the alkoxysilane, and the content of the 1 mol / liter aqueous ammonia solution in the 1 mol / liter aqueous ammonia water solution was changed to 1.0 ml / liter. , And a dry powder was obtained in the same manner as in Example 1 except that the particles were formed in one step.

As a result of measuring the particle size distribution and the particle size of the obtained powder with a coal counter, only one large particle size peak was observed, the average particle size was 3.262 μm, and the
It was confirmed that monodispersed particles having a V value of 1.56% were obtained. Next, the particles thus obtained were calcined at 640 to 660 ° C. for several hours in a nitrogen atmosphere to obtain particles 7-1 to 7-4 having properties shown in Table 7.

[0067]

[Table 7] In addition, initial compression curves for these particles were determined.
As an example, an initial compression curve of 7-3 particles is shown in FIG. As can be seen from this figure, all the particles were smooth curves without inflection points.

Comparative Example 2 In Comparative Example 1, 25 VTMS was used instead of MTMS.
g and dried in the same manner as in Comparative Example 1 except that the content of 1 mol / liter ammonia water in the 1 mol / liter aqueous ammonia water solution was changed to 0.1 ml / liter. A powder was obtained.

As a result of measuring the particle size distribution and the particle size of the obtained powder with a coal counter, only one large particle size peak was observed, the average particle size was 4.005 μm, and the C
It was confirmed that monodisperse particles having a V value of 1.60% were obtained. Next, the particles thus obtained were calcined at 270 to 400 ° C. for 2 hours in a nitrogen atmosphere to obtain particles 8-1 to 8-6 having properties shown in Table 8.

[0070]

[Table 8] Also, the compression curves of these particles were smooth curves without inflection points as in Example 1.

Comparative Example 3 Into a 2 liter separable flask, 1600 ml of an aqueous solution containing 0.25 ml / l of 1 mol / l aqueous ammonia was added, and 140 g of MTMS was added while stirring the mixture at 30 rpm with stirring blades. Then, an MTMS layer was formed on the upper layer. This was stirred at room temperature until the upper layer completely disappeared. Then, the stirring speed was increased to 75 rpm, and tetraethoxysilane (TEOS) was used.
A solution obtained by dissolving 75 g in 75 g of methanol was added. After further stirring for about 1 hour, 10 ml of 25% by weight ammonia water was added, and the mixture was heated at 50 ° C. for 3 hours in a thermostat.
Aged for hours. Thereafter, the same operation as in Example 1 was performed to obtain a dry powder.

As a result of measuring the particle size distribution and the particle size of the obtained powder with a coal counter, only one large particle size peak was observed, the average particle size was 4.21 μm, and the CV
It was confirmed that monodispersed particles having a value of 2.03% were obtained. Next, the particles thus obtained were baked at 550 ° C. for 9 hours in a nitrogen atmosphere. An initial compression curve was determined for the particles. The results are shown in the graph of FIG. As can be seen from this figure, an inflection point was confirmed.

[0073]

According to the present invention, it is easy to control the 10% compression modulus, and the monodisperse gradient composite particles having improved breaking strength without impairing the 10% compression modulus and the recovery rate. Can be easily obtained. The inclined composite particles are particularly preferably used as a spacer for a liquid crystal display device.

[Brief description of the drawings]

FIG. 1 is a graph showing initial compression curves of the gradient composite particles (1-4) obtained in Example 1 and the particles (7-3) obtained in Comparative Example 1.

FIG. 2 is a graph showing an initial compression curve of the composite particles obtained in Comparative Example 3.

Claims (13)

[Claims] 1. A gradient composite comprising two or more kinds of polyorganosiloxanes having different organic groups, wherein the composition changes stepwise or continuously from the particle center toward the surface. particle. 2. Sintering spherical composite particles having two or more types of polyorganosiloxanes having different organic groups and having a composition that changes stepwise or continuously from the particle center toward the surface. A gradient composite particle characterized by comprising: 3. A 10% compression modulus (X) of 19.6 GP
a (2000 kgf / mm ² ) or less, the breaking strength (Y) satisfies the relationship of Y (GPa) ≧ 0.13X−0.196, and the recovery rate is 90% or more. Graded composite particles. 4. The method according to claim 1, wherein two or more kinds of polyorganosiloxanes having different organic groups have different thermal decomposition temperatures of organic components.
The gradient composite particles according to claim 2 or 3, comprising a seed, and having a thermal decomposition temperature difference of 50 ° C or more. 5. A polyorganosiloxane having a low thermal decomposition temperature of an organic component is present so as to increase toward the center,
5. The gradient composite particles according to claim 4, wherein spherical particles present so as to increase the amount of polyorganosiloxane having a high thermal decomposition temperature of the organic component toward the surface side are fired. 6. The calcination is carried out at a temperature higher than the thermal decomposition temperature of the polyorganosiloxane having a low thermal decomposition temperature of the organic component and lower than the thermal decomposition temperature of the polyorganosiloxane having a high thermal decomposition temperature of the organic component. Or the gradient composite particle of 5. 7. The gradient composite particles according to claim 2, wherein the firing temperature is 200 to 700 ° C. 8. A polyorganosiloxane having a low thermal decomposition temperature of an organic component is a hydrolytic condensate of vinyltrimethoxysilane, and a polyorganosiloxane having a high thermal decomposition temperature of an organic component is hydrolytic condensation of methyltrimethoxysilane. The gradient composite particle according to any one of claims 4 to 7, which is a product. 9. The gradient composite particles according to claim 2, having an average particle size of 0.5 to 15 μm and a coefficient of variation (CV value) of the particle size distribution of 3.0% or less. 10. An organic silicon compound having 1 to 3 non-hydrolyzable groups and 3 to 1 alkoxyl group bonded to a silicon atom, at least two kinds of which are selected, hydrolyzed and condensed, After forming spherical composite particles having two or more kinds of polyorganosiloxanes and having a composition changing stepwise or continuously from the center of the particles toward the surface, the particles are dried, and then dried at 200 to 700 ° C. Sintering at a temperature of 1. The method for producing gradient composite particles. 11. An organosilicon compound having one to three non-hydrolyzable groups and three to one alkoxyl group bonded to a silicon atom, and one or two or more thereof selected from the group consisting of: A plurality of different organosilicon compounds are hydrolyzed and condensed in two or more stages, and have two or more polyorganosiloxanes, and the composition changes stepwise substantially from the particle center toward the surface. 11. The method of claim 10, wherein forming spherical composite particles. 12. Using two or more kinds of organosilicon compounds selected from organosilicon compounds having 1 to 3 non-hydrolyzable groups and 3 to 1 alkoxyl groups bonded to a silicon atom, An aqueous solution containing an organosilicon compound is hydrolyzed and condensed in one step while continuously changing the composition, and has two or more types of polyorganosiloxanes. The method according to claim 10, wherein a spherical composite particle which changes continuously above is formed. 13. A spacer for a liquid crystal display device, comprising the inclined composite particles according to claim 2. Description: