JP7015137B2 - Organic-inorganic composite particles - Google Patents

Description

The present invention relates to organic-inorganic composite particles.

Generally, a gap material (spacer) is used when controlling the distance between two parts such as a substrate in an electronic member to be constant. In particular, in liquid crystal displays (LCDs), liquid crystal display elements such as polymer-dispersed liquid crystal (PDLC) films, and organic EL displays (OLEDs), micron-order and high-precision spacers are required in terms of design. In such electronic members, inorganic particles such as silica particles or fine particles such as resin particles are used as spacers.

Inorganic particles are excellent in particle size accuracy and gap retention, but may not be used as a gap material when the hardness is high. Since the hard inorganic particles cannot be deformed by following the gap fluctuation caused by the load, they damage the wiring of the substrate and the peripheral members. The hard inorganic particles cannot be deformed by following the change in thickness due to the thermal expansion rate or thermal shrinkage of the liquid crystal display, and may foam at a low temperature.

On the other hand, since the resin particles have flexibility, there is little risk of damaging the wiring or the like, and the resin particles are easily deformed by following a change in thickness due to thermal expansion or heat shrinkage. However, when the resin particles are repeatedly loaded or have gap fluctuations due to tapping, vibration, thermal shock, etc., the particle size recovery is delayed due to the time lag during load-unloading. That is, the responsiveness to the load is poor.

Further, when the resin particles are repeatedly subjected to stress, sagging due to plastic deformation occurs and the gap holding property is impaired. The resin particles have insufficient medium- to long-term gap retention. In general, the particle size of the resin particles cannot change following repeated gap fluctuations. When the gap fluctuation is repeated, a gap is created between the substrate and the resin particles, and the resin particles move. Alternatively, the gap cannot be accurately maintained due to the fluctuation of the particle size of the resin particles.

In recent years, as electronic devices and the like have become thinner and smaller, the gap accuracy has become stricter in design. In addition, due to the expansion of the usage area such as portability and in-vehicle use, and the utilization of pressure sensing functions such as touch panels, the use of materials in an environment where slight vibrations and thermal shocks are repeatedly applied during movement and use is increasing. The thermal shock of micro-vibration causes gap fluctuation between the substrates. Therefore, spacer particles that immediately respond to load fluctuations and suppress plastic deformation (permanent strain) due to repeated compression as much as possible are desired.

Therefore, organic-inorganic hybrid particles typified by polyorganosiloxane are considered to be promising as spacers. The organic-inorganic hybrid particles have a particle size accuracy comparable to that of silica in addition to the flexibility of resin particles.

Organic-inorganic composite particles containing a specific polysiloxane as a main component and having hardness and mechanical resilience are disclosed as organic-inorganic hybrid particles for a spacer for a liquid crystal display board (for example, Patent Document 1). .. The polysiloxane here has organosilicon in which at least one carbon atom in the organic group is directly chemically bonded to the silicon atom. The organic-inorganic complex particles described in Patent Document 1 have a residual displacement of 5% or less after 10% deformation.

Japanese Unexamined Patent Publication No. 7-140472

However, the organic-inorganic complex particles described in Patent Document 1 do not have sufficient mechanical restoring force as a gap spacer to be subjected to repeated loading. In Patent Document 1, the definition of high recoverability is 0 to 5% of residual displacement after 10% deformation. This index represents the amount of residual displacement with respect to the particle size. According to the loaded displacement amount disclosed in the examples of Patent Document 1, the displacement does not return by about 1/2 at the maximum. From this, it can be seen that the particle size of the organic-inorganic complex particles described in Patent Document 1 does not recover to the original size after being loaded and then unloaded.

When the conventional spacer particles composed of organic-inorganic complex particles are used, a gap may be formed between the substrate and the particles when stress is repeatedly applied due to physical factors or thermal shock. Such spacer particles cannot precisely hold the gap due to the accumulation of deformation. That is, such spacer particles may have impaired gap retention.

Spacer particles that maintain excellent gap retention even in an environment where repeated micro-vibrations are applied, respond immediately to load fluctuations (high responsiveness), and have a particle size that does not leave strain against repeated compression. There is a demand for organic-inorganic composite particles suitable as spacer particles having a high recovery rate and more suppressed plastic deformation.

Therefore, an object of the present invention is to provide an organic-inorganic composite particle that can be deformed by following a fluctuation of a load and whose plastic deformation is further suppressed.

The organic-inorganic composite particles according to the present invention are organic-inorganic composite particles having a particle size Z made of a compound having a siloxane bond, and are loaded with a load F ₀ to obtain a displacement amount D ₀ , and then the displacement amount D _s is 0. Displacement of the particle size Z when the cycle of loading with a load F (F> F ₀ ) such that 08Z ≤ D _s ≤ 0.15Z, holding for 2 seconds, and then unloading to the load F ₀ is repeated 10 times. The quantity is characterized by satisfying the conditions of the following formulas (1) and (2).
{(DR- _DL ) / _DL ) _} × 100 <10% Equation (1)
{(D (10) -D (1)) / Z} x 100 <1% formula (2)
(Here, DL and DR are displacement amounts based on ( _Z - _{D 0} ) at the time of loading and unloading at the load F _m (F ₀ <F _m <F) in the first cycle, respectively. Yes, D (10) is the displacement amount at the time of the load F in the 10th cycle based on (Z-D ₀ ), and D (1) is the load in the 1st cycle based on (Z-D ₀ ). Displacement amount at F. The values of the loads F, F ₀ , F _m and the displacement amounts D _s , D ₀ , DL, _DR , _D (10), and D (1) are all minute compressions. It is a measured value obtained by using a testing machine.)

When the organic-inorganic composite particles of the present invention are removed by applying a predetermined load, the displacement amount of the particle size is within a predetermined range. The organic-inorganic composite particles of the present invention are excellent in responsiveness because they can immediately react to fluctuations in load. Further, the organic-inorganic composite particles of the present invention do not accumulate a displacement amount even if the load-unload cycle is repeated. The organic-inorganic composite particles of the present invention are highly elastic particles in which plastic deformation is further suppressed.

It is a schematic diagram explaining the displacement amount in the load-unloading cycle of the organic-inorganic composite particle of this embodiment. It is a schematic diagram explaining the displacement amount in the 1st load-unloading cycle of the organic-inorganic composite particle of this embodiment. It is a stress strain curve of a conventional composite particle. It is a stress strain curve at the time of the first load-unloading cycle of the organic-inorganic composite particle of this embodiment. It is a stress strain curve at the time of 10 load-unloading cycles of the organic-inorganic composite particle of this embodiment. It is a schematic diagram explaining the elasticity of the organic-inorganic composite particle of this embodiment. 6 is a stress-strain curve during the first load-unload cycle of the organic-inorganic composite particles of Example 1. 6 is a stress-strain curve of the organic-inorganic composite particles of Example 1 during 10 load-unload cycles. It is a stress strain curve at the time of the first load-unloading cycle of the organic-inorganic composite particle of Comparative Example 1. It is a stress-strain curve in the case of 10 load-unloading cycles of the organic-inorganic composite particles of Comparative Example 1.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

1. 1. Overall Structure The organic-inorganic composite particles of the present embodiment (hereinafter, also simply referred to as composite particles) are composed of a compound having a siloxane bond (Si—O—Si bond). In the composite particle of the present invention, the displacement amount of the particle size satisfies a predetermined condition when the load-unloading cycle is repeated.

Specifically, the composite particles of the present embodiment are loaded with a load F ₀ to obtain a displacement amount D ₀ , and then a load F (F>) in which the displacement amount D _s becomes 0.08Z ≤ D _s ≤ 0.15 Z. When the load-unloading cycle of loading with F ₀ ) and holding for 2 seconds and then unloading to the load F ₀ is repeated 10 times, the following equations (1) and (2) are satisfied. Z is the particle size when no load is applied. In the present specification, the particle size Z means the average particle size obtained by the Coulter counter method.

{(DR- _DL ) / _DL ) _} × 100 <10% Equation (1)
{(D (10) -D (1)) / Z} x 100 <1% formula (2)

DL and DR are displacement amounts based on (Z-D ₀ ) at the time of loading and _unloading at the load F _m (F ₀ <F _m <F) in the first cycle, respectively, and _D ( 10) is the displacement amount at the time of the load F in the 10th cycle based on (Z-D ₀ ), and D (1) is the displacement at the time of the load F in the 1st cycle based on (Z-D ₀ ). The quantity.

With reference to FIGS. 1 and 2, changes in particle size when the composite particles of the present invention are repeatedly loaded and unloaded will be described.

As shown in FIG. 1, the composite particle 10 has a particle size Z when no load is applied. The composite particles 10 are placed on a flat pressure plate, and a unloading load F ₀ having a displacement amount D ₀ (D ₀ is a value much smaller than 0.08 Z) using a circular flat plate indenter made of diamond having a diameter of 50 μm. Is applied. The unloading load in the first cycle is called the initial load. A load F having a displacement amount D _s (0.08Z ≦ D _s ≦ 0.15Z) is further applied to the composite particles 10.

The composite particle 10 is deformed by holding it for 2 seconds with the load F applied to the composite particle 10. The displacement amount at this time is determined by using the particle size (Z-D ₀ ) when the initial load is applied as the reference particle size, and is used as the displacement amount D (1) when the load is applied in the first cycle. Unloading load F ₀ is unloaded, the first cycle is completed, and the load-unloading in the second cycle is performed. While measuring the displacement amount of the composite particle 10, the same load-unloading cycle is repeated 10 times to obtain the displacement amount D (10) at the load load F in the 10th cycle.

The changes in load and particle size in the first load-unload cycle are shown in FIG. The load at the time of loading increases from the initial load F ₀ to the intermediate load F _m and then to the load load F. The load at the time of unloading decreases from the load load F through the intermediate load F _m to the unloading load F ₀ . Ideally, the particle size at the unloading load F ₀ o'clock is the same as the initial load F ₀ o'clock. _Let the displacement amount at the intermediate load F _m at the time of loading be DL, and let the displacement amount at the intermediate load F _m at the time of _unloading be DR. The intermediate load Fm at the time of loading and unloading is, for example, _0.5F . The displacement amounts _DL and _DR are obtained as the displacement amounts from the reference particle size in the same manner as described above.

As described above, the composite particle 10 of the present embodiment satisfies the condition of the following formula (1).
{(DR- _DL ) / _DL ) _} × 100 <10% Equation (1)
{(DR- _DL ) / _DL ) _} The value of × 100 is an index of followability to the load. {( _{DR-DL) / D L ) }} The larger the value of x100, that is, the larger the displacement amount at the time of unloading is larger than the displacement amount at the time of loading with the same load, the more the followability to the load becomes. Show bad things. If a large amount of strain due to elastic hysteresis loss remains, it takes time for the particle size to recover when the load is removed, resulting in poor responsiveness.

Since the value of {(DR- _DL ) / _DL ) _} × 100 of the composite particle 10 of the present embodiment is specified to be less than 10%, the particle size of the composite particle 10 is rapidly adjusted with respect to the load. Can follow and change. {( _{DR-DL) / D L ) }} The value of × 100 is preferably 5% or less, and more preferably less than 0% ( _DR < _DL ). It will be described later that ( _DR - _DL ) shows a negative value.

The composite particle 10 of the present embodiment satisfies the condition of the following formula (2) in addition to the condition of the above formula (1).
{(D (10) -D (1)) / Z} x 100 <1% formula (2)
The value of {(D (10) −D (1)) / Z} × 100 is an index of plastic deformability. The larger the value of {(D (10) -D (1)) / Z} × 100, that is, the displacement amount in the 10th cycle under load is larger than the displacement amount in the 1st cycle under load. The larger the value, the greater the plastic deformability.

In such composite particles, a delay (time lag) occurs before the particle size recovers after unloading, and strain is accumulated inside the particles. The amount of displacement increases with each load-unload cycle, resulting in greater particle crushing. When such particles are used as a gap material, they cannot accurately hold the gap.

In the composite particle 10 of the present embodiment, the value of {(D (10) −D (1)) / Z} × 100 is specified to be less than 1%, so that plastic deformation is sufficiently suppressed. Therefore, the composite particle 10 of the present embodiment has high elasticity. The value of {(D (10) −D (1)) / Z} × 100 is preferably 0.5% or less. In the composite particle 10 of the present embodiment, the displacement amount D (10) at the time of the load load in the 10th cycle may be smaller than the displacement amount D (1) at the time of the load load in the 1st cycle. The case of (D (10) <D (1)) will be described later.

The composite particles of the present invention preferably have a 10% compressive elastic modulus of 2 GPa or more and 20 GPa or less. Particles with a 10% compressive modulus too small are too soft and have a large displacement with respect to the load. Therefore, particles having a 10% compressive elastic modulus that is too small cannot fully exhibit the function as a spacer. On the other hand, particles having an excessively large 10% compressive elastic modulus are too hard as a spacer. Particles with an excessively large 10% compressive elastic modulus cause damage to peripheral members with which the particles are in contact.

If the 10% compressive elastic modulus of the composite particle made of a compound having a siloxane bond is 2 GPa or more, an appropriate substrate spacing can be maintained even if the load changes. Therefore, the composite particle having a 10% compressive elastic modulus of 2 GPa or more can be used. It can be used as a spacer. When the 10% compressive elastic modulus is 20 GPa or less, the elastic properties of the composite particles are more preferable.

The composite particles of the present invention preferably have an average particle size of 0.5 to 200 μm determined by the Coulter counter method. Composite particles having an average particle size within this range can be suitably used as a spacer in an electronic member or the like. The average particle size of the composite particles of the present invention is more preferably 1 to 100 μm. In particular, when used for liquid crystal panel applications, the average particle size of the composite particles is preferably 1 to 15 μm, more preferably 2 to 12 μm, and most preferably 3 to 7 μm.

Further, the coefficient of variation CV value of the particle size distribution of the composite particles of the present invention is preferably 5% or less. The CV value is obtained by the standard deviation of the particle size and the average particle size as shown by the mathematical formula (A1) described later. The method of calculating the CV value will be described later. Composite particles having a CV value of 5% or less can be suitably used as a spacer because the variation in particle size is small. The CV value of the composite particles is more preferably 2.5% or less. Further, the composite particles of the present embodiment are preferably spherical monodisperse particles.

The range of suitable average particle sizes for composite particles will vary depending on the application. Suitable average particle sizes are, for example, 6 to 16 μm for organic EL applications, 7 to 25 μm for PDLC applications, 25 to 50 μm for 3D shutter applications, and 40 to 120 μm for LED lighting applications.

2. 2. Manufacturing Method Next, a manufacturing method of the organic-inorganic composite particles of the present invention will be described.

The organic-inorganic composite particles of the present invention are derived from polysiloxane particles synthesized by the sol-gel method. Such polysiloxane particles can be produced by a method including a seed particle forming step, a particle growth step, and a firing step. Hereinafter, each step will be described.

<Seed particle formation process>
In the seed particle forming step, a silicon compound as a raw material is hydrolyzed and condensed in an aqueous solvent together with a catalyst to form droplet-shaped seed particles. As a result, a seed particle liquid in which the seed particles are dispersed in an aqueous solvent is obtained. The silicon compound used as a raw material is an alkoxide in which a non-hydrolyzable organic group and a hydrolyzable organic group are bonded to a silicon atom, and is represented by the following general formula (PS1).
R ¹ _n Si (OR ² ) _4-n general formula (PS1)

In the above general formula (PS1), R ¹ is selected from an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, and an aralkyl group having 7 to 20 carbon atoms. It is a non-hydrolytable organic group. At least one hydrogen atom in the alkyl group may be substituted with a methacryloyloxy group, an acryloyloxy group, or an epoxy group. ^R2 is an alkyl group having 1 to 6 carbon atoms, and n is an integer of 1 to 3. When n is 2 or more, the plurality of R ^1s may be the same or different from each other. When n is 2 or less, the plurality of hydrolyzable organic groups OR ² may be the same or different from each other.

The silicon compound represented by the general formula (PS1) is preferably trialkoxysilane (n = 1). The trialkoxysilane preferably occupies 60% or more (molar equivalent) of the entire raw material, and more preferably 80% or more (molar equivalent). Preferred trialkenylsilanes include, for example, methyltrimethoxysilane, methyltriethoxysilane, methyltripropoxysilane, methyltriisopropoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, propyltriethoxysilane, butyltrimethoxysilane, and the like. Phenyltrimethoxysilane, phenyltriethoxysilane, vinyltrimethoxysilane, vinyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-acryloyloxypropyltrimethoxysilane, γ-methacryloyloxypropyltrimethoxysilane, etc. Can be mentioned.

Among these, methyltrimethoxysilane and vinyltrimethoxysilane are suitable because they are excellent in the reactivity of hydrolysis condensation. Silicon compounds can be used alone or in combination of two or more.

Examples of the components that may be combined include compounds represented by the following general formula (PS2).
R ³ _m Si (OR ⁴ ) _4-m general formula (PS2)

In the above general formula (PS2), R ³ is selected from an alkyl group having 1 to 20 carbon atoms, an alkenyl group having 2 to 20 carbon atoms, an aryl group having 6 to 20 carbon atoms, and an aralkyl group having 7 to 20 carbon atoms. It is a non-hydrolytable organic group. At least one hydrogen atom in the alkyl group may be substituted with a methacryloyloxy group, an acryloyloxy group, or an epoxy group. R ⁴ is an alkyl group having 1 to 6 carbon atoms, and m is an integer of 0 to 3. When m is 2 or more, a plurality of R ^3s may be the same or different from each other. When m is 2 or less, the plurality of hydrolyzable organic groups OR ⁴ may be the same or different from each other.

In the above general formula (PS2), examples of the silicon compound (tetraalkoxysilane) having m = 0 include tetramethoxysilane, tetraethoxysilane, tetrapropoxysilane, and tetrabutoxysilane.

In the above general formula (PS2), examples of the silicon compound (dialkoxysilane) having m = 2 include dimethyldimethoxysilane, dimethyldiethoxysilane, and diphenyldimethoxysilane.

In the above general formula (PS2), examples of the silicon compound (monoalkoxysilane) having m = 3 include trimethylmethoxysilane, trimethylethoxysilane, triisobutylmethoxysilane, diisobutylmethylmethoxysilane, and triethylmethoxysilane.

When m = 1 in the general formula (PS2), the non-hydrolyzable organic group R ³ and the hydrolyzable organic group OR ⁴ are the non-hydrolyzable organic group R ¹ and water in the general formula (PS 1). A trialkoxysilane different from the degradable organic group OR ² is used.

The silicon compound is dissolved in an aqueous solvent together with a catalyst to prepare a raw material solution. The concentration of the silicon compound in the raw material solution is preferably 20% by mass or less. When the concentration of the silicon compound is in the range of 5 to 15% by mass, it is advantageous in terms of the particle size and volumetric efficiency of the seed particles produced.

As the aqueous solvent, a mixed solvent of water and a water-miscible organic solvent or water can be used. Examples of the water-miscible organic solvent include lower alcohols such as methanol, ethanol, propanol and butanol, ketones such as acetone, dimethyl ketone and methyl ethyl ketone, and ethers such as diethyl ether and dipropyl ether. .. The water-miscible organic solvent can be used alone by mixing with water. Two or more kinds of water-miscible organic solvents may be combined and used by mixing with water.

As the catalyst, a basic catalyst is preferable, and ammonia or amine can be used. The amine can be selected from, for example, monomethylamine, dimethylamine, monoethylamine, diethylamine and ethylenediamine. The catalyst may be used alone or in combination of two or more. Among the catalysts, ammonia is preferable from the viewpoint of low toxicity, easy removal from particles, and low cost.

The raw material solution may contain a stabilizer. The stabilizer enhances the solubility of the silicon compound and stabilizes the seed particles produced. Examples of the stabilizer include a surfactant and a polymer dispersant.

Since the silicon compound represented by the general formula (PS1) has a hydrolyzable organic group (OR ² ) bonded to a silicon atom, hydrolytic condensation occurs by stirring the raw material solution under predetermined conditions. The raw material solution can be stirred using a well-known stirrer. The pH at the start of the reaction is appropriately set according to the type of the silicon compound as a raw material. For example, in the case of methyltrimethoxysilane, the pH at the start of the reaction is preferably 9.7 to 11.7, more preferably 9.7 to 11.2. The reaction temperature is appropriately set according to the type of the silicon compound, but is preferably in the range of 0 to 50 ° C., for example.

Hydrolytic condensation of the silicon compound produces seed particles made of polyorganosiloxane having a Si—C bond. Polyorganosiloxane is, for example, soluble in alcohol, but insoluble in, for example, a mixture of water and alcohol. Therefore, a seed particle liquid in which droplet-shaped seed particles are dispersed in an aqueous solvent can be obtained.

The properties of the droplet-shaped seed particles are different from those of the conventionally known solid-shaped seed particles. The presence of the droplet-shaped seed particles is basically confirmed only in the liquid in which the seed particles are formed, not the particles that have undergone the washing step or the drying step. The droplet state can be determined, for example, by adding a large amount of alcohol to the seed particle solution and observing the dissolution of the particles. Alternatively, before observing with an optical microscope, the cover glass on the slide glass may be pressed with a finger, and then the crushed state of the particles may be observed with an optical microscope to determine the droplet state.

The accuracy of the particle size of the seed particles can be evaluated, for example, by the CV value. As described above, the CV value of the particles is determined by the standard deviation of the particle size and the average particle size. The average particle size of the seed particles is, for example, in the range of 1 to 50 μm. The CV value of the seed particles is preferably 10% or less, more preferably 5% or less.

In general, mixing a hydrophilic substance and a hydrophobic substance causes a phenomenon called phase separation. Alternatively, it is known that a substance having a hydrophilic group and a hydrophobic group in one molecule represented by a surfactant or the like forms micelles in which functional groups having the same properties face each other. The aggregate formed by such a difference in ease of mixing with water is flexible and exhibits elastic properties because no binding occurs in the aggregate.

On the other hand, the hydrolyzate of the silicon compound represented by the general formula (PS1) is a hydrophobic organic base (non-hydrolyzable organic group R ¹ ) and a hydrophilic silanol group obtained from the hydrolyzable organic group OR ² . And have. The organic base can form an aggregate and become a large elastic body that can be deformed in response to a load. When the silicon compound represented by the above general formula (PS1) is reacted in an environment having a relatively large amount of catalyst, the formation of Si—O—Si bonds between molecules by dehydration condensation of silanol groups is promoted. Since the degree of freedom in the formation of the aggregate is lost, it is not possible to obtain a large aggregate.

In order to obtain an aggregate with a large organic base exhibiting elastic properties, it is necessary to appropriately suppress the formation of Si—O—Si bonds. Further, by forming an aggregate formed by a large organic base, the formation of a dense Si—O skeleton is inhibited, so that an increase in the crosslink density can be suppressed. The aggregates and Si—O—Si bonds form pseudo-elastomer structures as soft and hard segments, respectively, resulting in organic-inorganic composite particles with moderate hardness and less plastic deformation. It is thought that it was.

The dense Si—O skeleton within the seed particles is formed when the growth of the seed particles is complete. During the growth of seed particles, a dense Si—O skeleton does not occur. The time to complete the growth of seed particles is uniquely determined by the synthetic conditions. By synthesizing particles under the same conditions using the same raw material solution in advance and observing the state of the raw material solution and the change in particle size, it is possible to grasp the time when the growth of seed particles is completed. The time for completing the growth of the seed particles is the time from when the raw material solution becomes cloudy until the growth of the seed particles stops. This time is referred to as the growth stop time.

In the present embodiment, the synthesis time in the seed particle forming step is preferably 40 to 80% of the growth arrest time, but is not always limited. If the seed particle synthesis time is too long, a dense Si—O skeleton is formed. On the other hand, if the synthesis time of the seed particles is too short, it becomes difficult to obtain monodisperse seed particles. By synthesizing seed particles in a time of 40 to 80% of the growth arrest time, seed particles having a relatively sparse Si—O skeleton can be efficiently formed. Since the seed particles can be subjected to the particle growth step before the growth of the seed particles is completed, the formation of aggregates of organic bases in the growth particles is less likely to be inhibited.

In order to obtain particles that can be deformed according to the load, it is required to keep the amount of catalyst low. In principle, it is desirable to reduce the amount of catalyst even when seed particles are synthesized. However, if the amount of catalyst is small during the synthesis of seed particles, it takes a long time for particle growth, and in the worst case, nuclei may not be generated. In addition, the particle size of the obtained particles fluctuates greatly, and the particle size accuracy expressed by the CV value tends to be high.

In order to obtain seed particles having an appropriate particle size and CV value, the catalyst concentration in the seed particle forming step is preferably 0.001 mol / L or more when, for example, methyltrimethoxysilane is used alone. More preferably, it is about 0.005 to 0.020 mol / L.

<Particle growth process>
In the particle growth step, seed particles are grown to obtain grown particles, and then the grown particles are solidified to obtain solidified particles. First, the silicon compound represented by the above general formula (PS1) is dissolved in an aqueous solvent to prepare a particle growth solution. As described above, as the silicon compound, methyltrimethoxysilane or vinyltrimethoxysilane is suitable. For example, the same type of silicon compound as that used for forming the seed particles can be used, but different types of silicon compounds may be used.

As the aqueous solvent, a water-miscible organic solvent as described above or water can be used. As mentioned above, the water-miscible organic solvent can be mixed with water alone. The water-miscible organic solvent may be mixed with water in combination of two or more. The particle growth solution can be prepared using a well-known stirrer.

The particle growth solution may contain a stabilizer. The stabilizer has an action of increasing the solubility of the silicon compound. The stabilizer is not particularly limited, and examples thereof include a surfactant, for example, an anionic surfactant. As the anionic surfactant, an alkyl sulfate having an alkyl group having 6 to 30 carbon atoms is preferable.

The alkyl sulfate can be selected from, for example, potassium salt, sodium salt and ammonium salt, and sodium dodecyl sulfate and ammonium dodecyl sulfate are suitable. The stabilizer also functions as a surface protectant for seed particles in which the formation of Si—O skeleton is sparse when the particle growth solution is mixed with the seed particle solution.

The particle growth solution thus prepared and the seed particle solution are mixed and stirred to allow the seed particles to absorb the silicon compound. As a result, the seed particles grow to become growth particles, and a growth particle liquid is obtained.

In the particle growth step, in order to make the Si—O skeleton sparse, it is preferable to synthesize the particles in a low catalyst concentration. Since the seed particle liquid containing the catalyst and the particle growth solution are mixed, the catalyst concentration in the liquid becomes small. For example, in the case of methyltrimethoxysilane, it is desirable to add the seed particle solution to the particle growth solution so that the catalyst concentration in the entire solution is 0.005 mol / L or less. The final catalyst concentration in the particle growth step is preferably 0.005 mol / L or less.

When the particle size of the target growth particles is large, the particle growth step may be repeated a plurality of times. By repeating the particle growth step, the catalyst concentration in the solution may decrease. If the amount of catalyst is too small, it will be difficult to obtain growth particles of the desired size. Therefore, it is desirable to add an appropriate catalyst as necessary to maintain an appropriate catalyst concentration of 0.005 mol / L or less. Is done.

When the growth particles reach the desired particle size, a new catalyst is added to the growth particle solution to hydrolyze and condense the silicon compound contained in the growth particles. Examples of the catalyst include basic catalysts as described in the formation of seed particles. By advancing the hydrolysis condensation of the silicon compound, the growth particles mature and solidify, and solidified particles are obtained. The solidified particles consist of polyorganosiloxanes with Si—C bonds.

After separating the solidified particles and the aqueous solvent, the fine particles and the like contained in the solidified particles are appropriately removed by washing. By drying the solidified particles after washing, composite particles having a sparse Si—O skeleton and an aggregate with an organic base can be obtained.

<Baking process>
The solidified particles after drying are calcined under the condition that the Si—C bond is maintained. By maintaining the Si—C bond, aggregates due to the organic base remain in the obtained composite particles. By firing under appropriate conditions, composite particles having a compressive strength suitable for the intended use can be obtained. The firing is preferably carried out at 200 ° C. to 1000 ° C. under an inert atmosphere such as nitrogen or in a vacuum. By firing under these conditions, composite particles having appropriate compressive strength and hardness as a spacer can be obtained. The firing temperature is more preferably 400 to 800 ° C.

The firing temperature is selected according to the type of organic group contained in the particles. In the case of particles having an organic group that is easily pyrolyzed, it is desirable to treat them at a relatively low temperature within the above-mentioned firing temperature range. On the other hand, in the case of particles having an organic group that is difficult to be thermally decomposed, it is preferable to treat the particles at a higher temperature within the above-mentioned firing temperature range.

For example, in the case of particles derived from methyltrimethoxysilane, the appropriate firing temperature is 600 to 730 ° C., and in the case of particles derived from vinyltrimethoxysilane, the appropriate firing temperature is 250 to 350 ° C. In either case, appropriate conditions may be selected according to the fracture strength and elastic modulus required for the target particles. The firing device is not particularly limited, and an electric furnace, a rotary kiln, or the like can be used. When a rotary kiln is used, it is advantageous because the particles can be fired while stirring.

The calcination can also be performed in the presence of oxygen (for example, in the air). Firing in the presence of oxygen promotes oxidative decomposition of organic components and generation of combustion heat. Therefore, in the presence of oxygen, firing is performed in an inert atmosphere or at a lower temperature than firing in vacuum. The preferable temperature range is a temperature that is 100 ° C. lower than the decomposition temperature of the organic group contained in the solidified particles and is lower than the decomposition temperature of the organic group.

Immediately raising the temperature to a temperature equal to or higher than the decomposition temperature of the organic group and firing, the organic group is rapidly decomposed and desorbed, and the breaking strength of the obtained particles is lowered. In some cases, the particles cannot withstand the rapid shrinkage and cracks occur. Furthermore, the organic group is excessively lost, and particles having the required flexibility cannot be obtained. By firing at an appropriate temperature according to the type of organic group, such a problem can be avoided.

Specifically, the particles obtained from methyltrimethoxysilane are preferably calcined at a temperature in the range of 250 to 350 ° C. When the decomposed and desorbed organic components burn on the spot, excessive heat may be transferred. For example, by reducing the oxygen concentration to 10% by volume or less, it is possible to prevent the decomposed and desorbed organic components from burning on the spot. Immediately removing the decomposed and desorbed organic components to the outside of the system by blowing air is one of the effective measures.

The amount of decomposition of an organic group can be grasped by comparing the peak intensity and carbon content of the organic group before and after firing by using an elemental analyzer such as an infrared spectroscopic analysis (IR) or a carbon / sulfur analyzer. It is possible to do. The optimum ratio of the decomposition amount can be selected according to the required fracture strength and elastic modulus. The residual ratio of organic groups can be inferred by measuring the residual ratio of carbon. The residual ratio of carbon is preferably 20% or more, more preferably 30 to 95%.

3. 3. Actions and effects The composite particles produced as described above are made of polysiloxane having a Si—C bond, and when a predetermined load-unload cycle is repeated, the displacement amount of the particle size satisfies a predetermined condition. Specifically, the composite particle of the present embodiment is loaded with a load F having a displacement amount D _s of 0.08Z ≤ D _s ≤ 0.15Z, held for 2 seconds, and then unloaded. When the cycle is repeated 10 times, the conditions of the above equations (1) and (2) are satisfied.

Such properties are not found in conventional composite particles. An elastic hysteresis loss as shown in FIG. 3 is confirmed in the stress-strain curve when the same load-unloading cycle is performed 10 times on the conventional composite particle. At the time of loading, the amount of displacement increases with the load in the direction of arrow A, and the particles are compressed. At the time of unloading, the displacement amount decreases with the load in the direction of arrow B, but the displacement amount of the particles does not return to the state before the load even with the load F ₀ (unloading load). This phenomenon is repeated every load-unloading cycle, and the amount of displacement at the time of load F (load load) increases.

In FIG. 3, with F _{m =} 0.5 _F , the displacement amount DL during the loading and the displacement amount DR during the unloading in the first cycle are obtained. The displacement amount DR during _unloading is larger than the displacement amount _DL during loading. It has been shown that the conventional composite particles have a slower change in particle size at the time of unloading than at the time of loading, and have poor responsiveness. Since the conventional composite particles have such poor responsiveness, the value of {(DR- _DL ) / _DL ) _} × 100 is 10% or more.

As described above, in the conventional composite particle, the displacement amount at the time of loading is increased by repeating the load-unloading cycle. This is because the strain is accumulated in the conventional composite particles by repeating the load-unload cycle, and the particles are crushed and plastically deformed. Since conventional composite particles are easily plastically deformed in this way, the value of {(D (10) −D (1)) / Z} × 100 is 1% or more.

An example of the stress-strain curve of the composite particle of this embodiment is shown in FIG. FIG. 4 shows the displacement amount in the load and unloading in the first cycle. At the time of loading, the amount of displacement increases with the load in the direction of arrow A, and the particles are compressed. At the time of unloading, the displacement amount decreases with the load in the direction of arrow B. When the load becomes F ₀ (unloading load) due to unloading, the particles return to the state before loading.

In the case of FIG. 4, the displacement amount DL in the middle of loading and the displacement amount _DR in the middle of unloading at a load of _0.5F are almost equal. That is, the value of ₍ DR _−DL ) is substantially 0. It can be seen that the particle size of the particles of the present embodiment changes at the same speed as when loaded even when unloading, and the displacement followability to the load is excellent. Since the composite particles of the present embodiment have such good responsiveness, the value of {(DR- _DL ) / _DL ) _} × 100 is less than 10%.

FIG. 5 shows an example of the stress-strain curve obtained by repeating the load-unload cycle 10 times for the composite particle of the present embodiment. In this case, the value of {(D (10) −D (1)) / Z} × 100 is less than 1%. Since the composite particles of the present embodiment satisfy the condition of the above formula (2), the degree of crushing is small even if the load-unloading cycle is repeated, and the particles recover to the initial particle size. Therefore, the gap retention is not impaired.

Moreover, in the example shown in FIG. 5, the value of {(D (10) −D (1)) / Z} × 100 is negative. The displacement amount at the time of load loading in the 10th cycle is smaller than the displacement amount at the time of load loading in the 1st cycle. This is evidence that the composite particles of the present embodiment have strong elastic properties close to those of a completely elastic body. The reason will be explained below.

Generally, in the elastic region, stress and strain are statically uniquely determined, but not dynamically. It can be likened to a state in which a weight suspended from a spring (elastic body) vibrates up and down around the elongation obtained from the spring constant. The load unloading test in which the composite particles are provided in this embodiment corresponds to a dynamic test. It is considered that the composite particles swing back in a direction in which the strain is reduced while the load is applied and the particles are held for 2 seconds.

A negative value of {(D (10) −D (1)) / Z} × 100 indicates that the strain generated in the particle is an elastic deformation and the particle is an elastic body. Since the composite particle of the present embodiment is an elastic body, it has a strong force (repulsive force) to return to the original particle size against compression, and in addition to exhibiting excellent followability (responsiveness) to a load. , It is considered that it works more effectively from the viewpoint of medium- to long-term gap retention. For the same reason, the value of {(DR- _DL ) / _DL ) _} × 100 can also be negative.

FIG. 6 shows a state in which the value of {(D (10) −D (1)) / Z} × 100 becomes negative. After the load in the first cycle, the particle size when unloading to the unloading load F ₀ is (Z-D _{0 *} ). In the second cycle, the displacement amount D _{0 *} when the unloading load F ₀ is D _{0 *} <D ₀ , and the displacement amount D (2) ^* when the load load F is D (2) ^* <. It becomes D (1). After repeating the load-unload cycle, the displacement amount D (10) ^* at the load load F in the 10th cycle becomes D (10) ^* <D (1). The fact that the composite particles have a large repulsive force appears in such a change in particle size.

In the load unloading test of the present invention, the amount of displacement from the reference particle size (ZD ₀ ) is obtained for the convenience of the apparatus. D ₀ is the amount of displacement when the initial load F ₀ . Since the composite particles of the present embodiment have a large repulsive force, they may return to the particle size Z at the time of no load when the unloading load is _F0 . In this case, the displacement amount is a negative value, specifically −D ₀ .

The composite particles of the present embodiment are produced by forming seed particles in a limited synthesis time, growing the seed particles, and then firing them under predetermined conditions. The condition of 2) is satisfied.

Generally, in the synthesis of polyorganosiloxane particles, it is known that if the concentration of the catalyst (ammonia) is high, dense particles grow, and if the concentration of the catalyst is low, the particles grow in a sparse state. .. During the synthesis of seed particles, the amount of catalyst is relatively large, and a dense Si—O skeleton is formed in the seed particles. Therefore, the density of the Si—O skeleton in the seed particles and the density of the Si—O skeleton in the grown portion are different.

The difference in the density of the Si—O skeleton thus generated is not completely eliminated even through the manufacturing process, and remains in the manufactured composite particles. It is known that the difference in the density of the Si—O skeleton causes the difference in the refractive index in the composite particles. The boundary of the density of the Si—O skeleton is confirmed as the interface of the core-shell structure having the seed particles as the core and the grown portion as the shell.

When producing the composite particles of the present embodiment, the synthesis time of the seed particles is set short to be 40 to 80% of the growth stop time, so that the growth of the seed particles is not completed. Since such seed particles are grown, it is possible to produce composite particles in which the core-shell structure does not exist. The absence of a core-shell structure in the composite particles can be confirmed by general optical observation.

The absence of a core-shell structure in the composite particles is evidence that the formation of a dense Si—O skeleton within the seed particles was suppressed. As described above, the density difference of the Si—O skeleton exists in the composite particle as the refractive index difference of the interface. If no difference in the refractive index of the interface is confirmed in the composite particles, there is no difference in the density of the Si—O skeleton in the composite particles. That is, the skeleton in the composite particle is uniform.

In the composite particles having no core-shell structure, the organic base in the particles is uniformly present with a high degree of freedom due to the suppression of the formation of the dense Si—O skeleton of the seed particles. The composite particles are formed with aggregates of larger organic bases to increase their elastic properties. As a result, composite particles in which the occurrence of plastic deformation and elastic hysteresis loss due to the Si—O skeleton were suppressed were obtained.

When the composite particles of the present embodiment are used as a gap material for a liquid crystal panel or the like, even if the particles are compressed and deformed by an impact or an external force and the particle size changes, the recovery speed is fast, so that the particles follow the gap of the substrate. be able to. It becomes difficult to create a gap between the substrate and the gap material, and it is possible to prevent the gap material from moving. Further, as a result of the excellent followability, the distortion is reduced, and as a result, excellent gap retention can be exhibited even with a repeated load.

When the composite particles of the present embodiment and the adhesive resin are mixed and used as an adhesive for holding a gap, the influence of plastic deformation of the adhesive resin itself can be suppressed. In this case, it can be expected to be a highly reliable gap-retaining adhesive even during long-term use.

When a load is applied, the composite particle of the present embodiment immediately changes to a displacement amount corresponding to the load, so that the response speed is very fast. Moreover, since the composite particles of the present embodiment have such characteristics that the accuracy can be maintained for a long period of time, the composite particles of the present embodiment can be used as a gap holding material for a high-sensitivity pressure sensor or the like. Can also be suitably used.

When producing the composite particles of the present embodiment, the silicon compound as a raw material is stirred together with a catalyst in an aqueous solvent to form seed particles, so that the raw material permeates into the particles and is seeded in a swelling state. The particle size of the particles grows. The particles in the process of synthesis are not solid but droplets. For example, when alcohol is added to the particles during synthesis, the particle interface disappears and it is confirmed that the particles are eluted. From such a phenomenon, it can be confirmed that the particles in the process of synthesis are in the form of droplets.

Larger aggregates are formed in the droplet-shaped seed particles due to the presence of the organic base with a high degree of freedom. As a result, the elastic properties of the obtained composite particles are increased, so that plastic deformation is suppressed. Furthermore, since the presence of the organic base having a high degree of freedom interferes with the formation of the Si—O skeleton, it is possible to suppress the plastic deformation caused by the Si—O skeleton. As a result, particles having excellent elastic properties can be obtained.

In the conventional general method for synthesizing polyorganosiloxane particles, the amount of catalyst is relatively large, and the raw materials are gradually supplied. Such a method is called a two-layer method or a uniform method, and particles grow while forming a Si—O skeleton. In the conventional manufacturing method, the existence range of the organic base is limited, so that a large elastic body portion is not formed.

In the conventional manufacturing method, the elastic modulus of the obtained particles is lowered, but it is not sufficient in terms of elastic properties and suppression of plastic deformation. Further, in the conventional two-layer method, there is a limitation on the silicon compound as a raw material that the specific gravity must be lower than that of the solvent, and only a specific silicon compound can be used.

In the method for producing composite particles of the present embodiment, the reaction time can be remarkably shortened as compared with the conventional method such as the two-layer method, and the productivity is improved. Particles grow in a short time. This is also one of the reasons why the formation of the Si—O skeleton is sparse and an aggregate with a large organic base is obtained. Moreover, the method for producing composite particles of the present embodiment has an advantage that the silicon compound as a raw material is not limited and the range of selection of the silicon compound that can be used as a raw material is wide.

4. Modifications The present invention is not limited to the above embodiment, and can be appropriately modified within the scope of the gist of the present invention.

In the above embodiment, as the load F applied at the time of loading, a load that deforms 10% of the particle size Z of the composite particles 10 can be used, but the load F is not limited to this. Similar results can be obtained by holding for 2 seconds with a load F deforming 8 to 15% of the particle size Z of the composite particle 10 and unloading. The unloading load F ₀ can be any value, but it is preferably close to 0, and specifically, the value of the minimum load (origin load) in the microcompression tester is preferably used. F ₀ can be appropriately set in the range of 0 <F ₀ <0.1 F.

The diameter of the circular flat plate indenter that applies the load F to the composite particles 10 can be appropriately selected according to the particle size Z of the composite particles 10 to be measured. The diameter of the circular plate indenter can be changed to, for example, 200 μm or 500 μm.

The following functional particles can also be obtained by using the composite particles of the embodiment as mother particles and subjecting the surface to a coating treatment to provide a functional layer. Examples of the functional particles include conductive particles and fixed particles.

The conductive particles can be produced by providing a conductive layer as a functional layer on the surface of the composite particles as mother particles. The conductive particles can be used, for example, as gap-holding particles having electrical conductivity between the upper and lower substrates in a liquid crystal display element or a semiconductor element, or as an anisotropic conductive material containing the gap-holding particles.

Since such conductive particles do not fluctuate in gap even in an environment where a load is applied over the medium to long term, stable electrical connectivity can be maintained. The conductive particles containing the composite particles of the present embodiment are spacers having excellent long-term reliability.

The conductive layer can be formed by using any material that can obtain conductivity. Materials that can be used include, for example, metals, metal salts, conductive resins and the like. Preferred materials are gold, silver, or alloys (solder, etc.). The thickness of the conductive layer is not particularly limited, but if it has a thickness of 50 nm or more, stable conductivity can be exhibited. By forming a metal core on the surface of the composite particle and performing a pretreatment, or by performing a surface treatment with a silane coupling agent or the like, the adhesion between the composite particle and the conductive layer can be enhanced.

The conductive particles can secure an electrical connection if the electric resistance value is 30 Ω or less.

The fixed particles can be produced by providing a fixed layer made of a thermoplastic resin on the surface of the composite particles as the mother particles. When the fixed particles are used as an in-plane spacer for a liquid crystal display element, the fixed particles are fixed to the substrate by heating and melting the fixed layer. Even if the liquid crystal flows when the liquid crystal is injected, the spacer made of the fixed particles is fixed to the substrate, so that the movement is suppressed.

Such fixed particles have a potential repulsive force against compressive deformation when sandwiched between the upper and lower substrates, and thus become particles that are more difficult to move. The fixed layer of the fixed particles exerts an effect of preventing the flow of the liquid crystal when the liquid crystal is injected and the movement of the liquid crystal against impact and external force during actual use. Therefore, the fixed particles containing the composite particles of the present embodiment become spacers whose movement is further suppressed.

The reason why particles with a large repulsive force are more difficult to move will be explained as follows. The maximum static friction force F is expressed by F = μN using the static friction coefficient μ and the normal force N. The normal force N is that when an object is pushing a solid surface such as another object or the ground that the object is in contact with, the solid surface of the same magnitude and opposite to the component perpendicular to the surface of the force is the object. It is the force that pushes back. Here, when the fixed particles are sandwiched between the upper and lower substrates, when the repulsive force of the object (fixed particles) is large, the force pushing the surface of the solid (substrate) becomes large, so the normal force N becomes large and the maximum static friction. The force F also increases. Therefore, the fixed particles having both the fixing force and the repulsive force can be a spacer that is more difficult to move than the conventional fixing particles.

Such fixed particles can be used as an in-plane spacer that is difficult to move in a liquid crystal display element of a normal vacuum injection method or a drop injection (ODF) method. Especially in the ODF method, the fixed particles can be effectively used. Compared with the conventional vacuum injection method, the ODF method is attracting attention as it can reduce the amount of liquid crystal used, the number of processes, and the process time, and can reduce the manufacturing cost of the liquid crystal cell.

In this ODF method, a predetermined amount of liquid crystal calculated and estimated from the cell gap is dropped and held narrowly. For this reason, a pressure change occurs in the plane at the time of bonding, and the liquid crystal spreads and flows toward the surroundings. Since the fixed particles containing the composite particles of the present embodiment have high elastic recovery characteristics that can follow pressure changes and stickability that does not move due to liquid crystal flow, they can be suitably used as spacers to be placed on the substrate. can.

Any material containing a thermoplastic component can be used to form the anchoring layer. The thermoplastic component preferably has a glass transition temperature of 150 ° C. or lower. As the thermoplastic component, a polymer of a monofunctional vinyl-based monomer can be preferably used, and examples thereof include styrene resin and acrylic resin.

The monofunctional vinyl-based monomer is a monomer having one carbon-carbon unsaturated double bond. Specific examples include vinyl aromatic hydrocarbons (styrene, α-methylstyrene, vinyltoluene, α-chlorostyrene, o-chlorostyrene, m-chlorostyrene, p-chlorostyrene, p-ethylstyrene, etc.) and acrylic acids. , Acrylate esters (methyl acrylate, ethyl acrylate, propyl acrylate, butyl acrylate, hexyl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate, β-hydroxyethyl acrylate, β-aminoethyl acrylate, N, N-dimethylaminoethyl acrylate, γ-Hydroxypropyl acrylate, etc.), methacrylic acid, methacrylic acid ester (methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, hexyl methacrylate, 2-ethylhexyl methacrylate, cyclohexyl methacrylate, β-hydroxyethyl methacrylate, β-aminoethyl methacrylate, etc. N, N-dimethylaminoethyl methacrylate, γ-hydroxypropyl methacrylate, glycidyl methacrylate, etc.), and vinylsilane (vinyltrimethoxysilane, vinyltriethoxysilane, vinyltrimethylsilane, γ-acryloxypropyltrimethoxysilane, γ-methacryloxy). Propyltrimethoxysilane, etc.).

These monofunctional vinyl-based monomers may be used alone or in combination of two or more. Further, in order to impart a stronger bonding force, a curable component such as an epoxy resin or a curing agent may be mixed. By polymerizing the monofunctional vinyl-based monomer, a resin film made of a vinyl-based polymer such as a styrene-based resin, an acrylic-based resin, or a methacrylic-based resin is formed.

The thickness of the fixing layer is not particularly limited, but is preferably about 0.05% to 10% of the diameter of the composite particles. When the thickness of the fixing layer is within this range, a sufficient fixing force can be obtained without adversely affecting the gap width.

By surface-treating the surface of the composite particles with a silane coupling agent or the like before providing the fixing layer, the adhesion between the composite particles and the resin layer can be enhanced. As the silane coupling agent, a vinyl-based silane coupling agent is preferably used. A vinyl group having a silane group (for example, an alkoxysilane group, a halogenosilane group, an acetoxysilane group, etc.) having reactivity with a silanol group on the surface of the composite particle and having reactivity with a monomer for forming a thermoplastic resin layer. Any coupling agent having can be used.

The vinyl group is interpreted in the broadest sense and includes an acryloyl group, a methacryloyl group, an allyl group, etc. in addition to the vinyl group itself. Specific examples of the above vinyl-based silane coupling agent include, for example, vinyltrimethoxysilane, vinyltriethoxysilane, vinyltris (β-methoxyethoxy) silane, γ-acryloxypropyltrimethoxysilane, and γ-methacryloxypropyltrimethoxy. Silane, vinyltricrolsilane, vinyltris (β-methoxy) silane, N-β- (N-vinylbenzylaminoethyl) -γ-aminopropyltrimethoxysilane, vinyltriacetoxysilane, γ-methacryloxypropylmethyldimethoxysilane, etc. Can be mentioned.

The fixed particles can be heated under predetermined conditions and fixed on the substrate. If it is heated at 150 ° C. or lower for less than 1 hour, there is no problem in productivity.

It is preferable that the fixed particles have a fixing rate of 50% or more in the blow-off test. The fixed particles having a fixing rate of 50% or more can withstand the flow of the liquid crystal at the time of injecting the liquid crystal. Since the fixed particles are not washed away at the edge of the panel, the in-plane gap can be stably maintained.

5. Evaluation method In the examples described later, the following load unloading cycle test is performed on the organic-inorganic composite particles. Each physical property value of the organic-inorganic composite particle is evaluated by the following method.

<Load unloading cycle test>
As shown in FIG. 1, the composite particles 10 are arranged on a flat pressure plate, and an initial load _F0 is applied using a circular flat plate indenter made of diamond having a diameter of 50 μm. After that, the load is increased to a predetermined load load F at a speed of 0.14 mN / sec. The load load F is a load in which 8 to 15% of the particle size Z of the composite particle 10 is deformed. It is held for 2 seconds with this load load F, and the displacement amount D (1) at the time of the load load in the first load is obtained. After that, the load is unloaded up to the unloading load _F0 at the same speed.

As the load load F, the load applied when the 10% compressive elastic modulus was measured in advance was used. The displacement ratio deviates slightly from 10% because it is affected by the variation in the particle size of each composite particle applied in the microcompression test, but the displacement ratio is included in the range of 8 to 15%. I just need to be there. The initial load (unloading load) F ₀ that can be set on the device fluctuates according to the value of the load load F. In this embodiment, F ₀ = 0.01 mN when F <1.96 mN, F ₀ = 0.2 mN when F <196 mN ≤ F <196 mN, and F ₀ = 2 mN when F ≥ 196 mN.

Further, using the displacement amount DL at the time of loading at the time of load F _m (F _{m =} 0.5F) and the displacement amount DR at the time of unloading at the same time of load _{F m} , {( _DR ). _-DL ) / _DL )} × Calculate the value of 100.

The same load unloading cycle is repeated 10 times, and the displacement amount D (10) at the time of load loading at the 10th load is obtained. Using the particle size Z when no load is applied, the first displacement amount D (1), and the tenth displacement amount D (10), {(D (10) -D (1)) / Z} × 100. Calculate the value.

<particle size, CV value>
The average particle size Z and the standard deviation of the particle size of the composite particles are determined using a Coulter counter (Multisizer IVe, manufactured by Beckman Coulter Co., Ltd.). The coefficient of variation CV value of the particle size distribution can be calculated by the following mathematical formula (A1).
CV value (%) = (standard deviation of particle size / average particle size) X100 formula (A1)

<10% compressive modulus>
The 10% compressive elastic modulus of the composite particle can be determined based on the compressive behavior. The compression behavior is observed by applying a load to the composite particles using a microcompression tester (MCTM-200, manufactured by Shimadzu Corporation). The 10% compressive elastic modulus can be calculated by the following method.

The composite particles as a sample are sprayed on a flattened plate (material: SKS flat plate), and a load is applied at a constant speed to deform the particles until the compressive displacement amount becomes 10% of the particle size Z. A diamond circular flat plate indenter having a diameter of 50 μm is used to apply the load. The load F when the particles are deformed by 10% and the compressive displacement amount Dx are obtained, and the 10% compressive elastic modulus E is calculated using the following mathematical formula (A2). K is the Poisson's ratio of the particles (constant 0.38), and r is the radius of the particles.

<Carbon residual rate>
For the composite particles as a sample, the carbon content in the particles was measured. In the carbon content measurement, carbon was quantified by a high frequency induction heating combustion-infrared absorption method using a carbon / sulfur analyzer (manufactured by LECO, CS844 type). The operating conditions of the carbon / sulfur analyzer are as follows.
Analysis time: 40 seconds Cycle time: 90 seconds Carrier gas: Oxygen (purity 99.6%)
Driving gas: Nitrogen Carrier gas flow rate: 3 L / min In addition, gas dosing of the carbon / sulfur analyzer was not used, and a steel lens manufactured by LECO was used as a standard sample, and the quantification was performed with one inspection amount line. The ratio of the quantitative value obtained by the above measurement to the theoretical value of the carbon content in the solidified particles was calculated as the residual ratio of carbon. The carbon content in the solidified particles takes a different value depending on the composition of the silicon compound used as a raw material. The theoretical value of the carbon content in the solidified particles is, for example, 17.9% when methyltrimethoxysilane is used as a raw material and 30.4% when vinyltrimethoxysilane is used.

<Electrical resistance value>
The electrical connectivity of conductive particles is evaluated by measuring the electrical resistance value. Specifically, the electric resistance value is measured for each of the 20 composite particles using a microcompression tester (manufactured by Shimadzu Corporation), and the average value of the 20 measured values is taken as the electric resistance value.

<Fixing rate>
The fixing performance of the fixed particles is evaluated by a blow-off test. To perform the blow-off test, first, the fixed particles are sprayed on a slide glass and heated at 120 ° C. for 30 minutes. The number of particles on the slide glass is defined as the number N0 before the blow-off test.

Then, the slide glass is cooled to room temperature, and nitrogen gas is blown under predetermined conditions for 30 seconds. The spraying conditions are a nozzle pressure of 0.01 MPa, a nozzle-slide glass distance of 10 mm, and a spraying angle of 45 °. The fixation rate bp is calculated by the following mathematical formula (A3), where the number of particles existing on the slide glass after the blow-off test is N1.
bp = (N1 / N0) x100 formula (A3)

6. Examples Next, examples according to the present invention will be described.

<Example 1>
(Seed particle formation process)
360 g of methyltrimethoxysilane (hereinafter abbreviated as MTMS) and 48 g of ion-exchanged water as raw materials were housed in a 1 L plastic container and stirred at about 200 rpm. After 3 hours, a uniform solution was obtained.

1800 g of water and 18 g of a 1N aqueous ammonia solution were placed in a 2 L glass container, and the above-mentioned uniform solution was added to prepare a raw material solution. Seed particles were grown using this raw material solution, and the growth arrest time was determined. The raw material solution became cloudy several tens of seconds after the uniform solution was added, and nuclei of particles were generated in the solution. The particle size growth of the seed particles stopped 20 minutes after the raw material solution became cloudy. The growth arrest time is 20 minutes.

The particle synthesis time in the seed particle forming step in Example 1 is set to 50% of the growth arrest time, that is, 10 minutes.

Using the same raw material solution as described above, synthesis was carried out for 10 minutes to form seed particles, and a seed particle solution was obtained. The particle size of the seed particles obtained from the optical microscope image was about 6.3 μm.

(Particle growth process)
A solution for particle growth was prepared by stirring 14962 g of water, 3000 g of MTMS, and 38 g of a 1% aqueous solution of ammonium dodecyl sulfate in a 20 L reaction vessel. 1500 g of the seed particle solution was added to the particle growth solution, and the mixture was stirred at about 80 rpm while checking the particle size with an optical microscope at any time. As a result, the seed particles grew and the grown particles were obtained. The ammonia concentration in the particle growth step is 0.0006 mol / L.

After about 2 hours, the growth of the particle size stopped. Here, 200 g of 25% by mass aqueous ammonia was added to mature the particles. The particles solidified to give solidified particles. Then, it was separated into solid and liquid by decantation and washed with methanol three times. Then, it was air-dried for 2 days, and further heated at 110 ° C. to dry. The dried solidified particles had an average particle size of 16.34 μm and a CV value of 1.37%.

(Baking process)
The dried solidified particles were fired at 640 ° C. for 6 hours in a nitrogen atmosphere while stirring with a tilted rotary kiln (manufactured by Nagato Electric Works Co., Ltd.) to obtain composite particles of Example 1.

The load-bearing property of the composite particle of Example 1 {( _{DR-DL) / D L ) }} x 100 and the plastic deformability {(D (10) -D (1)) / Z} x 100, and others. It is summarized in Table 1 below together with the physical property values of. FIG. 7 shows the stress-strain curve during the first load-unloading cycle, and FIG. 8 shows the stress-strain curve during the 10-load-unloading cycle.

As shown in FIG. 7, the composite particles of Example 1 have an excellent displacement followability with respect to the load because the particle size changes at the time of unloading as well as at the time of loading. Further, as shown in FIG. 8, the composite particle of Example 1 has a large repulsive force because the displacement amount at the time of loading in the 10th cycle is smaller than that in the 1st cycle.

<Example 2>
The composite particles of Example 2 were obtained by the same method as in Example 1 except that the firing temperature of the solidified particles in the rotary kiln was changed to 680 ° C.

The load-bearing property of the composite particle of Example 2 {( _{DR-DL) / D L ) }} x 100 and the plastic deformability {(D (10) -D (1)) / Z} x 100, and others. It is summarized in Table 1 below together with the physical property values of.

<Example 3>
In the firing step, the same method as in Example 1 was used except that the solidified particles were fired at 300 ° C. for 6 hours in an air atmosphere using a forced hot air circulation type dryer (SPHH-202 manufactured by ESPEC CO., LTD.). The composite particles of Example 3 were obtained.

The load-bearing property of the composite particle of Example 3 {( _{DR-DL) / D L ) }} x 100 and the plastic deformability {(D (10) -D (1)) / Z} x 100, and others. It is summarized in Table 1 below together with the physical property values of.

<Example 4>
(Seed particle formation process)
180 g of MTMS as a raw material and 1800 g of ion-exchanged water were housed in a 2 L glass container and stirred at about 200 rpm. After 3 hours, a uniform solution was obtained. 18 g of 1N ammonia water was added to the uniform solution to prepare a raw material solution. Seed particles were grown using this raw material solution, and the growth arrest time was determined. The raw material solution became cloudy several tens of seconds after the addition of aqueous ammonia, and nuclei of particles were generated in the solution. The particle size growth of the seed particles stopped 20 minutes after the raw material solution became cloudy. The growth arrest time is 20 minutes.

The particle synthesis time in the seed particle forming step in Example 4 is set to 50% of the growth arrest time, that is, 10 minutes.

Using the same raw material solution as described above, synthesis was carried out for 10 minutes to form seed particles, and a seed particle solution was obtained. The particle size of the seed particles obtained from the optical microscope image was about 2.1 μm.

(Particle growth process)
A solution for particle growth was prepared by stirring 17955 g of water, 1800 g of MTMS, and 45 g of a 1% aqueous solution of ammonium dodecyl sulfate in a 20 L reaction vessel. The whole amount of the seed particle solution was added to the particle growth solution, and the mixture was stirred at about 80 rpm while checking the particle size with an optical microscope at any time. As a result, the seed particles grew and the grown particles were obtained. The ammonia concentration in the particle growth step is 0.0008 mol / L.

After about 1 hour, the growth of the particle size stopped. Here, 50 g of 25% by mass aqueous ammonia was added to mature the particles. The particles solidified to give solidified particles. Then, the particles were separated, washed, and dried by the same method as in Example 1 to obtain dried solidified particles. The dried solidified particles had an average particle size of 4.53 μm and a CV value of 1.68%.

(Baking process)
The dried solidified particles were calcined under the same conditions as in Example 1 to obtain composite particles of Example 4. The load-bearing property of the composite particle of Example 4 {( _{DR-DL) / D L ) }} x 100 and the plastic deformability {(D (10) -D (1)) / Z} x 100, and others. It is summarized in Table 1 below together with the physical property values of.

<Example 5>
(Seed particle formation process)
180 g of MTMS, 1800 g of ion-exchanged water, and 0.1 g of sodium dodecyl sulfate as raw materials were placed in a 2 L glass container and stirred at about 200 rpm. After 3 hours, a uniform solution was obtained. 18 g of 1N ammonia water was added to the uniform solution to prepare a raw material solution. Seed particles were grown using this raw material solution, and the growth arrest time was determined. The raw material solution became cloudy several tens of seconds after the addition of aqueous ammonia, and nuclei of particles were generated in the solution. The particle size growth of the seed particles stopped 20 minutes after the raw material solution became cloudy. The growth arrest time is 20 minutes.

The particle synthesis time in the seed particle forming step in Example 5 is set to 50% of the growth arrest time, that is, 10 minutes.

Using the same raw material solution as described above, synthesis was carried out for 10 minutes to form seed particles, and a seed particle solution was obtained. The particle size of the seed particles obtained from the optical microscope image was about 1.1 μm.

(Particle growth process)
A solution for particle growth was prepared by stirring 17955 g of water, 1800 g of MTMS, and 45 g of a 1% aqueous solution of ammonium dodecyl sulfate in a 20 L reaction vessel. The whole amount of the seed particle solution was added to the particle growth solution, and the mixture was stirred at about 80 rpm while checking the particle size with an optical microscope at any time. As a result, the seed particles grew and the grown particles were obtained. The ammonia concentration in the particle growth step is 0.0008 mol / L.

After about 1 hour, the growth of the particle size stopped. Here, 50 g of 25% by mass aqueous ammonia was added to mature the particles. The particles solidified to give solidified particles. Then, the particles were separated, washed, and dried by the same method as in Example 1 to obtain dried solidified particles. The dried solidified particles had an average particle size of 2.15 μm and a CV value of 1.98%.

(Baking process)
The dried solidified particles were calcined under the same conditions as in Example 1 to obtain composite particles of Example 5. The load-following holdability of the composite particles of Example 5 {( _{DR-DL) / D L ) }} x 100 and the plastic deformability {(D (10) -D (1)) / Z} x 100. It is summarized in Table 1 below together with other physical property values.

<Example 6>
(Seed particle formation process)
240 g of MTMS as a raw material and 24 g of ion-exchanged water were housed in a 1 L plastic container and stirred at 30 ° C. and about 200 rpm. After 3 hours, a uniform solution was obtained,

A raw material solution was prepared by accommodating 1200 g of water and 12 g of 1N ammonia water in a 2 L glass container and adding all of the above-mentioned uniform solution while stirring at 20 ° C. and 80 rmp. Seed particles were grown using this raw material solution, and the growth arrest time was determined. The raw material solution became cloudy several tens of seconds after the uniform solution was added, and nuclei of particles were generated in the solution. The particle size growth of the seed particles stopped 20 minutes after the raw material solution became cloudy. The growth arrest time is 20 minutes.

The particle synthesis time in the seed particle forming step in Example 6 is set to 50% of the growth arrest time, that is, 10 minutes.

Using the same raw material solution as described above, synthesis was carried out for 10 minutes to form seed particles, and a seed particle solution was obtained. The particle size of the seed particles obtained from the optical microscope image was about 14.8 μm.

(Particle growth process)
In this embodiment, the particle growth step is repeated three times to obtain solidified particles having a large particle size.

A solution for particle growth was prepared by stirring 936 g of initial water, 192 g of MTMS, and 24 g of a 1% aqueous solution of ammonium dodecyl sulfate in a 2 L reaction vessel. 500 g of the seed particle solution was added to the particle growth solution, and the mixture was stirred at 25 ° C. and 50 rpm. At this time, the ammonia concentration is 0.0025 mol / L. After 35 minutes after the seed particles grew, particles having a particle size of 23.7 μm were confirmed.

・ From the second time onward, the same operation as the first time was performed twice more. The ammonia concentration at the second time was 0.00075mol / L, and the particle size obtained at the end of the second time was 36.4 μm. The ammonia concentration in the third final synthesis step was 0.00047 mol / L.

Then, the same aging, separation, washing and drying as in Example 1 were carried out to obtain dried solidified particles. The dried solidified particles had an average particle size of 53.84 μm and a CV value of 2.04%.

(Baking process)
The dried solidified particles were calcined under the same conditions as in Example 1 to obtain composite particles of Example 6. The load-bearing property of the composite particle of Example 6 {(DR-DL) / _DL )} x 100 and the plastic deformability {( _D (10) _-D (1)) / Z} x 100, and others. It is summarized in Table 1 below together with the physical property values of.

<Example 7>
(Seed particle formation process)
240 g of MTMS as a raw material and 16 g of ion-exchanged water were housed in a 1 L plastic container and stirred at 30 ° C. and about 200 rpm. After 3 hours, a uniform solution was obtained.

A raw material solution was prepared by accommodating 1200 g of water and 12 g of 1N ammonia water in a 2 L glass container and adding all the above-mentioned uniform solution while stirring at 20 ° C. and 80 rpm. Seed particles were grown using this raw material solution, and the growth arrest time was determined. The raw material solution became cloudy several tens of seconds after the uniform solution was added, and nuclei of particles were generated in the solution. The particle size growth of the seed particles stopped 20 minutes after the raw material solution became cloudy. The growth arrest time is 20 minutes.

The particle synthesis time in the seed particle forming step in Example 7 is set to 50% of the growth arrest time, that is, 10 minutes.

Using the same raw material solution as described above, synthesis was carried out for 10 minutes to form seed particles, and a seed particle solution was obtained. The particle size of the seed particles obtained from the optical microscope image was about 10.0 μm.

(Particle growth process)
In this embodiment, the particle growth step is repeated four times to obtain solidified particles having a large particle size.

A solution for particle growth was prepared by stirring 936 g of initial water, 192 g of MTMS, and 24 g of a 1% aqueous solution of ammonium dodecyl sulfate in a 2 L reaction vessel. 400 g of the seed particle solution was added to the particle growth solution, and the mixture was stirred at 25 ° C. and 50 rpm. At this time, the ammonia concentration is 0.0021 mol / L. Seed particles grew, and 40 minutes later, particles having a particle size of 15.8 μm were confirmed.

・ Addition (2nd, 3rd, 4th)
The same operation as the first time was performed three more times. In the second time, the ammonia concentration was 0.00050 mol / L, and the particle size at the end was 27.7 μm. At the third time, the ammonia concentration was 0.00037 mol / L, and the particle size at the end was 49.5 μm. In the fourth final synthesis step, the ammonia concentration was 0.00016 mol / L.

Then, the same aging, separation, washing and drying as in Example 1 were carried out to obtain dried solidified particles. The dried solidified particles had an average particle size of 106.0 μm and a CV value of 1.15%.

(Baking process)
The dried solidified particles were calcined under the same conditions as in Example 1 to obtain composite particles of Example 7. The load-bearing property of the composite particle of Example 7 {( _{DR-DL) / D L ) }} x 100 and the plastic deformability {(D (10) -D (1)) / Z} x 100, and others. It is summarized in Table 1 below together with the physical property values of.

<Example 8>
(Seed particle formation process)
240 g of MTMS as a raw material and 16 g of ion-exchanged water were housed in a 1 L plastic container and stirred at 33 ° C. and about 200 rpm. After 3 hours, a uniform solution was obtained.

A raw material solution was prepared by accommodating 1200 g of water and 12 g of 1N ammonia water in a 2 L glass container and adding all the above-mentioned uniform solution while stirring at 20 ° C. and 80 rpm. Seed particles were grown using this raw material solution, and the growth arrest time was determined. The raw material solution became cloudy several tens of seconds after the uniform solution was added, and nuclei of particles were generated in the solution. The particle size growth of the seed particles stopped 20 minutes after the raw material solution became cloudy. The growth arrest time is 20 minutes.

The particle synthesis time in the seed particle forming step in Example 8 is set to 50% of the growth arrest time, that is, 10 minutes.

Using the same raw material solution as described above, synthesis was carried out for 10 minutes to form seed particles, and a seed particle solution was obtained. The particle size of the seed particles obtained from the optical microscope image was about 13.5 μm.

(Particle growth process)
In this embodiment, the particle growth step is repeated 5 times to obtain solidified particles having a large particle size.

A solution for particle growth was prepared by stirring 936 g of initial water, 192 g of MTMS, and 24 g of a 1% aqueous solution of ammonium dodecyl sulfate in a 2 L reaction vessel. 400 g of the seed particle solution was added to the particle growth solution, and the mixture was stirred at 25 ° C. and 50 rpm. At this time, the ammonia concentration is 0.0021 mol / L. Seed particles grew, and 40 minutes later, particles having a particle size of 23.2 μm were confirmed.

・ Addition (2nd, 3rd, 4th, 5th)
The same operation as the first time was performed four more times. In the second time, the ammonia concentration was 0.00050 mol / L, and the particle size at the end was 38.6 μm. At the third time, the ammonia concentration was 0.00037 mol / L, and the particle size at the end was 56.9 μm. At the fourth time, the ammonia concentration was 0.00035mol / L, and the particle size at the end was 77.7 μm. In the fifth final synthesis step, the ammonia concentration was 0.00015 mol / L.

Then, the same aging, separation, washing and drying as in Example 1 were carried out to obtain dried solidified particles. The dried solidified particles had an average particle size of 156.3 μm and a CV value of 1.79%.

(Baking process)
The dried solidified particles were calcined under the same conditions as in Example 1 to obtain composite particles of Example 8. The load-bearing property of the composite particle of Example 8 {( _{DR-DL) / D L ) }} x 100 and the plastic deformability {(D (10) -D (1)) / Z} x 100, and others. It is summarized in Table 1 below together with the physical property values of.

<Example 9>
Using the composite particles obtained in Example 4 as mother particles, a conductive layer was provided on the surface by the following procedure to prepare conductive particles.

First, a metal core was formed on the surface of a predetermined amount of composite particles. To form the metal nuclei, 10 g of the composite particles were immersed in 130 mL of a mixed solvent of isopropyl alcohol and methanol, and 0.2 g of chloroauric acid (HAuCl · 4H ₂ O) and 2.6 ml of 3-aminopropyltrimethoxysilane were added. In addition, it was reduced with 0.084 g of sodium tetrahydroborate (NaBH ₄ ).

10 g of particles having metal nuclei formed on the surface were dispersed in 475 mL of water, and 28 g of polyvinylpyrrolidone, 28.65 g of silver nitrate, and 375 mL of a 25 mass% ammonia aqueous solution were added. A silver film was formed on the surface of the composite particles by adding 250 mL of a 3.57 mol / L formalin aqueous solution to reduce the silver ions in the liquid. In this way, the composite particles of this example having a silver film as a conductive layer were obtained. The metal thickness of the silver film was 0.14 μm.

The load-bearing property of the composite particle of Example 9 {( _{DR-DL) / D L ) }} x 100 and the plastic deformability {(D (10) -D (1)) / Z} x 100, and others. It is summarized in Table 2 below together with the physical property values of.

<Example 10>
Using the composite particles obtained in Example 4 as mother particles, a fixed resin layer was provided on the surface by the following procedure to prepare fixed particles.

(Silane coupling agent surface treatment)
To 100 g of the composite particles obtained in Example 4, 1200 g of methanol and 500 g of 25% by mass aqueous ammonia were added to prepare a particle dispersion. 40 g of 3-methacryloxypropyltrimethoxysilane was added dropwise at 5 g / min while stirring the obtained particle dispersion at 100 rpm at 30 ° C. The particle dispersion was stirred at 70 ° C. for 3 hours.

The particles after stirring were separated from the liquid by a centrifuge and dispersed in methanol for decantation. After repeating this operation several times, methanol was removed and the particles were air-dried. The air-dried particles were heated to 150 ° C. and dried to obtain composite particles surface-treated with a silane coupling agent.

(Fixed layer coating)
50 g of the surface-treated composite particles were dispersed in a mixed solution of 1000 g of methanol and 2500 g of ethylene glycol. 150 g of polyvinylpyrrolidone (PVP) was added to the obtained particle dispersion while stirring at 30 ° C. at 100 rpm. After 30 minutes from the addition, it was confirmed that PVP was sufficiently dissolved, and 120 g of styrene, 25 g of 2,2'-azobisisobutyronitrile, and 3 g of mercaptoacetic acid were added. The mixture was stirred at 65 ° C. at 60 rpm for 8 hours.

The particles were separated from the liquid by a centrifuge and then dispersed in water for decantation. After repeating this operation several times, the aqueous dispersion of the particles was frozen in liquid nitrogen and dried using a freeze-dryer. In this way, the composite particles of Example 10 in which a polystyrene (PSt) layer as a fixing layer was formed on the surface were obtained.

The load-bearing property of the composite particle of Example 10 {( _{DR-DL) / D L ) }} x 100 and the plastic deformability {(D (10) -D (1)) / Z} x 100, and others. It is summarized in Table 2 below together with the physical property values of.

<Example 11>
Composite particles different from those of Example 10 were used as mother particles, and a fixed resin layer was provided on the surface in the same procedure as in Example 10 to prepare fixed particles.

(Seed particle formation process)
500 g of MTMS as a raw material and 5000 g of ion-exchanged water were housed in a 6 L glass container and stirred at about 100 rpm. After 3 hours, a uniform solution was obtained. A raw material solution was prepared by adding 50 g of 1N ammonia water to the uniform solution. Seed particles were grown using this raw material solution, and the growth arrest time was determined.

The raw material solution became cloudy several tens of seconds after the addition of aqueous ammonia, and nuclei of particles were generated in the solution. The particle size growth of the seed particles stopped 20 minutes after the raw material solution became cloudy. The growth arrest time is 20 minutes.

The particle synthesis time in the seed particle forming step in Example 11 is set to 50% of the growth arrest time, that is, 10 minutes.

Using the same raw material solution as described above, synthesis was carried out for 10 minutes to form seed particles, and a seed particle solution was obtained. The particle size of the seed particles obtained from the optical microscope image was about 1.8 μm.

(Particle growth process)
A solution for particle growth was prepared by stirring 33000 g of water, 4950 g of MTMS, and 16.5 g of a 1% aqueous solution of ammonium dodecyl sulfate in a 50 L reaction vessel. 5500 g of a seed particle solution was added to the particle growth solution, and the mixture was stirred at about 20 rpm while checking the particle size with an optical microscope at any time. As a result, the seed particles grew and the grown particles were obtained. The ammonia concentration in the particle growth step is 0.0011 mol / L.

After about 3 hours, the growth of the particle size stopped. Here, 500 g of 25% by mass aqueous ammonia was added to mature the particles. The particles solidified to give solidified particles. Then, it was separated into solid and liquid by decantation and washed with methanol three times. Then, it was air-dried for 2 days, and further heated at 150 ° C. to dry. The dried solidified particles had an average particle size of 3.65 μm and a CV value of 2.56%.

(Baking process)
The dried solidified particles were fired at 300 ° C. for 5 hours in an atmospheric atmosphere while stirring with a tilted rotary kiln (manufactured by Nagato Electric Works Co., Ltd.) to obtain composite particles used in Example 11.

(Silane coupling agent surface treatment)
The obtained composite particles (100 g) were surface-treated with a silane coupling agent by the same method as in Example 10.

(Fixed layer coating)
50 g of the surface-treated composite particles were dispersed in a mixed solution of 1000 g of methanol and 2500 g of ethylene glycol. The same treatment as in Example 10 was performed except that 120 g of styrene was changed to 120 g of ethyl methacrylate. In this way, the composite particles of Example 11 in which the polyethyl methacrylate (PEMA) layer as a fixing layer was formed on the surface were obtained.

The load-bearing property of the composite particle of Example 11 {( _{DR-DL) / D L ) }} x 100 and the plastic deformability {(D (10) -D (1)) / Z} x 100, and others. It is summarized in Table 2 below together with the physical property values of.

<Example 12>
(Seed particle formation process)
300 g of vinyltrimethoxysilane (hereinafter abbreviated as VTMS) and 1500 g of ion-exchanged water as raw materials were housed in a 2 L glass container and stirred at about 200 rpm. After 1 hour, a uniform solution was obtained. A raw material solution was prepared by adding 0.5 g of 1N ammonia water to the uniform solution. Seed particles were grown using this raw material solution, and the growth arrest time was determined.

The raw material solution became cloudy 17 minutes after the addition of aqueous ammonia, and nuclei of particles were generated in the solution. The particle size growth of the seed particles stopped 60 minutes after the raw material solution became cloudy. The growth arrest time is 60 minutes.

The particle synthesis time in the seed particle forming step in Example 12 is set to 50% of the growth arrest time, that is, 30 minutes.

Using the same raw material solution as described above, synthesis was carried out for 30 minutes to form seed particles, and a seed particle solution was obtained. The particle size of the seed particles obtained from the optical microscope image was about 6.5 μm.

(Particle growth process)
A solution for particle growth was prepared by stirring 1350 g of water, 500 g of VTMS, and 150 g of a 1% aqueous solution of ammonium dodecyl sulfate in a 5 L reaction vessel. To the particle growth solution, 1050 g of the sheet particle solution and 0.1 g of 1N ammonia water were added, and the mixture was stirred at about 80 rpm while checking the particle size with an optical microscope at any time. The seed particles grew and the grown particles were obtained. The ammonia concentration in the particle growth step is 0.00013 mol / L.

After about 3 hours, the growth of the particle size stopped. Here, 10 g of 25% by mass aqueous ammonia was added to mature the particles. The particles solidified to give solidified particles. Then, it was separated into solid and liquid by decantation and washed with methanol three times. Then, it was naturally dried over 2 days and further heated at 80 ° C. to obtain dried solidified particles. The dried solidified particles had an average particle size of 11.12 μm and a CV value of 1.85%.

(Baking process)
The dried solidified particles were calcined at 200 ° C. for 6 hours in a nitrogen atmosphere while stirring with a rotary kiln similar to the above to obtain composite particles of Example 12.

The load-bearing property of the composite particle of Example 12 {( _{DR-DL) / D L ) }} x 100 and the plastic deformability {(D (10) -D (1)) / Z} x 100, and others. It is summarized in Table 1 below together with the physical property values of.

<Example 13>
The composite particles of Example 13 were obtained by the same method as in Example 1 except that the particle synthesis time in the seed particle forming step was set to 80% of the growth arrest time.

The load-bearing property of the composite particle of Example 13 {( _{DR-DL) / D L ) }} x 100 and the plastic deformability {(D (10) -D (1)) / Z} x 100, and others. It is summarized in Table 1 below together with the physical property values of.

<Comparative Example 1>
In the firing step, composite particles of Comparative Example 1 were obtained by the same method as in Example 1 except that the muffle furnace (KBF728N manufactured by Koyo Thermo System Co., Ltd.) was used and fired in air at 360 ° C. for 6 hours.

The load-following property of the composite particle of Comparative Example 1 {(DR-DL) / _DL )} × 100 and the plastic deformability {( _D (10) _-D (1)) / Z} × 100, and others. It is summarized in Table 3 below together with the physical property values of. FIG. 9 shows the stress-strain curve during the first load-unloading cycle, and FIG. 10 shows the stress-strain curve during the 10-load-unloading cycle.

It is shown in FIG. 9 that the composite particles of Comparative Example 1 have a slower change in particle size at the time of unloading than at the time of loading and are inferior in load followability. Further, as shown in FIG. 10, the composite particles of Comparative Example 1 are easily plastically deformed because the displacement amount at the time of loading is increased by repeating the load-unloading cycle.

<Comparative Example 2>
The composite particles of Comparative Example 2 are produced by the conventional two-layer method.

1600 g of ion-exchanged water and 1 g of 25 mass% ammonia water were placed in a 2 L glass container and stirred at about 20 rpm. Here, 160 g of MTMS was gradually added to form an MTMS phase on an aqueous phase containing ammonia. Ammonia in this synthesis is 0.008 mol / L.

After about 5 hours, the MTMS phase disappeared and became uniform. To this, 10 g of 25 mass% ammonia water was added to mature the particles. Then, the particles were separated, washed, and dried by the same method as in Example 1 to obtain dried solidified particles. The dried solidified particles had an average particle size of 4.58 μm and a CV value of 1.83%.

The dried solidified particles were calcined under the same conditions as in Example 1 to obtain composite particles of Comparative Example 2. The load-bearing property of the composite particle of Comparative Example 2 {( _{DR-DL) / D L ) }} x 100 and the plastic deformability {(D (10) -D (1)) / Z} x 100, and others. It is summarized in Table 3 below together with the physical property values of.

<Comparative Example 3>
The composite particles of Comparative Example 3 are produced by a conventional uniform method.

360 g of MTMS and 48 g of ion-exchanged water were placed in a 1 L plastic container and stirred at about 200 rpm. After 3 hours, a uniform MTMS aqueous solution was obtained.

1800 g of water and 18 g of 1N ammonia water were placed in a 2 L glass container, and the entire amount of MTMS aqueous solution was added. The ammonia concentration in the obtained mixture is 0.008 mol / L.

After about 1 hour, the growth of the particle size stopped. Here, 10 g of 25% by mass aqueous ammonia was added to mature the particles. Then, the particles were separated, washed, and dried by the same method as in Example 1 to obtain dried solidified particles. The dried solidified particles had an average particle size of 6.05 μm and a CV value of 1.47%.

The dried solidified particles were calcined under the same conditions as in Example 1 to obtain composite particles of Comparative Example 3. The load-bearing property of the composite particle of Comparative Example 3 {( _{DR-DL) / D L ) }} x 100 and the plastic deformability {(D (10) -D (1)) / Z} x 100, and others. It is summarized in Table 3 below together with the physical property values of.

<Comparative Example 4>
A fixing layer is formed on the surface using silica particles as mother particles.

(Seed particle formation process)
180 g of MTMS as a raw material, 1800 g of ion-exchanged water, and 0.1 g of sodium dodecyl sulfate were housed in a 2 L glass container and stirred at about 200 rpm. After 3 hours, a uniform solution was obtained. 18 g of 1N ammonia water was added to the uniform solution to prepare a raw material solution. Seed particles were grown using this raw material solution, and the growth arrest time was determined.

The raw material solution became cloudy several tens of seconds after the addition of aqueous ammonia, and nuclei of particles were generated in the solution. The particle size growth of the seed particles stopped 20 minutes after the raw material solution became cloudy. The growth arrest time is 20 minutes.

The particle synthesis time in the seed particle forming step in Comparative Example 4 is set to 50% of the growth arrest time, that is, 10 minutes.

Using the same raw material solution as described above, synthesis was carried out for 10 minutes to form seed particles, and a seed particle solution was obtained. The particle size of the seed particles obtained from the optical microscope image was about 2.78 μm.

(Particle growth process)
18,000 g of water and 2700 g of MTMS were stirred in a 20 L reaction vessel to prepare a particle growth solution. The entire amount of the seed particle solution was added to the particle growth solution, and the mixture was stirred at about 80 rpm while checking the particle size with an optical microscope at any time. As a result, the seed particles grew and the grown particles were obtained. The ammonia concentration in the particle growth step is 0.0008 mol / L.

After about 1 hour, the growth of the particle size stopped. Here, 50 g of 25% by mass aqueous ammonia was added to mature the particles. The particles solidified to give solidified particles. Then, it was separated into solid and liquid by decantation and washed with methanol three times. Then, it was air-dried for 2 days, and further heated at 110 ° C. to dry. The dried solidified particles had an average particle size of 6.10 μm and a CV value of 1.41%.

(Baking process)
The dried solidified particles were calcined in air at 460 ° C. for 13 hours while stirring with a tilted rotary kiln (manufactured by Nagato Electric Works Co., Ltd.). Since the firing is performed for 13 hours, the Si—C bond in the raw material of the solidified particles is not maintained. In this way, the silica particles used in Comparative Example 4 were obtained.

(Silane coupling agent surface treatment)
The obtained silica particles were surface-treated with a silane coupling agent by the same method as in Example 10.
(Fixed layer coating)
The fixing layer was coated in the same manner as in Example 10 to obtain silica particles of Comparative Example 4 in which a polystyrene (PSt) layer as a fixing layer was formed on the surface.

The load-bearing property of the silica particles of Comparative Example 4 {( _{DR-DL) / D L ) }} x 100 and the plastic deformability {(D (10) -D (1)) / Z} x 100, and others. It is summarized in Table 2 below together with the physical property values of.

As shown in Table 1 above, when the composite particles of Examples 1 to 8, 12, and 13 were repeatedly loaded and unloaded by applying a predetermined load, {(DR- _DL ) / _DL ) _} . It has the conditions of × 100 <10% and {(D (10) −D (1)) / Z} × 100 <1%. These composite particles can quickly follow the load and deform. Moreover, these composite particles have high elasticity because they have low plastic deformability.

In Examples 1 to 8, 12, and 13, seed particles were formed in a synthesis time limited to 40 to 80% of the growth arrest time, and the seed particles were grown to cause the organic base to meet in the growth particles. A coalescence was formed. In each case, the final catalyst concentration in the particle growth step is relatively small, 0.0008 mol / L or less. Moreover, in Examples 1 to 8, 12, and 13, the firing was performed under the condition that the Si—C bond was maintained, so that sufficient elasticity could be ensured.

As shown in Table 2 above, even when the functional layer is provided using the composite particles of Example 4 as the mother particles (Examples 9, 10 and 11), {(DR- _DL ) / _DL ) _} x 100. It has the conditions of <10% and {(D (10) -D (1)) / Z} × 100 <1%. It has been shown that the composite particles of Example 9 provided with the conductive layer have appropriate conductivity, and the composite particles of Examples 10 and 11 provided with the fixing layer have excellent fixing properties.

As shown in Table 3 above, when the composite particles of Comparative Examples 1 to 3 were repeatedly loaded and unloaded by applying a predetermined load, {( _{DR −DL} ) / _DL )} × 100 <10. % And {(D (10) -D (1)) / Z} × 100 <1% does not have the condition. It is presumed that the composite particles of Comparative Example 1 were fired at 360 ° C. in the air, so that the organic groups in the raw material (MTMS) were excessively lost, the load followability was impaired, and the plastic deformability was increased.

The composite particles of Comparative Example 2 were produced by a conventional two-layer method, and the composite particles of Comparative Example 3 were produced by a conventional uniform method. In Comparative Examples 2 and 3, the seed particle synthesis time was set independently of the growth arrest time. Moreover, the final amount of catalyst in the particle growth step is as high as 0.008 mol / L. Therefore, in Comparative Examples 2 and 3, it is presumed that the growth of the seed particles was completed and a dense Si—O skeleton was formed in the seed particles. In this case, even if the particles are fired under conditions where the Si—C bond can be maintained (640 ° C. in a nitrogen atmosphere), the Si—O skeleton such as the composite particles of the example cannot be made into sparse and highly elastic particles. It is presumed that it could not be done and the plastic deformability increased.

Since the silica particles of Comparative Example 4 provided with the fixing layer have a long firing time of 13 hours, the organic groups in the raw material are lost and the mother particles are hard and have no elasticity. It is presumed that such fixed particles are affected by the plastic deformability of the fixed layer (resin layer), and the plastic deformability of the particles as a whole is increased.

The composite particles of the present embodiment can be applied to any application for maintaining a gap between the upper and lower substrates at a constant distance. For example, it can be widely used as a liquid crystal display element including a polymer dispersed liquid crystal or a 3D shutter, a semiconductor element such as an organic EL or LED, an adhesive, an anisotropic conductive film, and a gap holding material such as a pressure sensor.

The composite particles of the present embodiment are particularly effective in members used in medium- to long-term load-bearing environments such as touch panels, portables, flexible particles, and wearables (watches, etc.).

Claims (5)

It is an organic-inorganic composite particle having a particle size Z, which is formed from a compound containing trialkoxysilane as a raw material and is composed of a compound having a siloxane bond.
After loading with a load F ₀ to obtain a displacement amount D ₀ , and then loading with a load F (F> F ₀ ) at which the displacement amount D _s becomes 0.08Z ≤ D _s ≤ 0.15Z and holding for 2 seconds, An organic-inorganic composite particle characterized in that the displacement amount of the particle size Z satisfies the conditions of the following formulas (1) and (2) when the cycle of unloading to a load F ₀ is repeated 10 times.
{(DR- _DL ) / _DL ) _} × 100 <10% Equation (1)
{(D (10) -D (1)) / Z} x 100 <1% formula (2)
(Here, DL and DR are displacement amounts based on ( _Z - _{D 0} ) at the time of loading and unloading at the load F _m (F ₀ <F _m <F) in the first cycle, respectively. Yes, D (10) is the displacement amount at the time of the load F in the 10th cycle based on (Z-D ₀ ), and D (1) is the load in the 1st cycle based on (Z-D ₀ ). Displacement amount at F.) The organic-inorganic composite particle according to claim 1, wherein the 10% compressive elastic modulus is 2 to 20 GPa. The organic-inorganic composite particle according to claim 1 or 2, wherein the particle size Z is 0.5 to 200 μm, and the coefficient of variation CV value of the particle size distribution is 5% or less. The organic-inorganic composite particle according to any one of claims 1 to 3, wherein the surface is covered with a conductive layer. The organic-inorganic composite particle according to any one of claims 1 to 3, wherein the surface is covered with a fixing layer.

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