JP2023087095A - Production method of polymethylsilsesquioxane particles - Google Patents

Abstract

To provide polymethylsilsesquioxane particles with small CV values and a production method thereof.SOLUTION: A production method of polymethylsilsesquioxane particles comprises hydrolysis condensation of a compound represented by formula (1), CH3Si(OR1)3, in the presence of water, an anionic surfactant, and an amine having a boiling point of 50°C or more. (In the formula (1), each R1 represents a C1-4 alkyl group, where the multiple occurrences of R1 may be identical or different.)SELECTED DRAWING: None

Description

TECHNICAL FIELD The present invention relates to polymethylsilsesquioxane particles and a method for producing the same.

Polymethylsilsesquioxane particles are particles having an inorganic structure and an organic structure, and are attracting attention in various fields. As a method for obtaining polymethylsilsesquioxane particles, for example, Patent Document 1 discloses an aqueous dispersion of polysilsesquioxane fine particles by mixing a dispersion stabilizer, a basic catalyst and trialkoxysilanes in the presence of an aqueous solvent. is described, and specifically, aqueous ammonia is used as the basic catalyst.

WO2006/070846

However, as a result of investigation by the present inventors, as in Patent Document 1, when aqueous ammonia is used as a basic catalyst, the coefficient of variation of the particle size of the obtained polymethylsilsesquioxane particles (hereinafter referred to as " (also referred to as "CV value") increased.

Accordingly, an object of the present invention is to provide polymethylsilsesquioxane particles having a small CV value of particle diameter and a method for producing the same.

The present invention is as follows.
[1] A method for producing polymethylsilsesquioxane particles by hydrolyzing and condensing a compound represented by the following formula (1) in the presence of water, an anionic surfactant, and an amine having a boiling point of 50°C or higher.
_CH3Si ( ^OR1 ) ₃ (1)
(In formula (1) above, R ¹ represents an alkyl group having 1 to 4 carbon atoms, and multiple R ^1s may be the same or different.)
[2] The production method according to [1], wherein the amine having a boiling point of 50°C or higher includes at least one amine having a pKa of 6 or higher.

According to the present invention, an amine having a boiling point higher than a predetermined value is used in the hydrolytic condensation of methyltrialkoxysilane represented by the predetermined formula. Sun particles can be obtained.

In the production method of the present invention, a compound represented by the following formula (1), that is, methyltrialkoxysilane, is hydrolyzed and condensed in the presence of water, an anionic surfactant, and an amine having a boiling point of 50° C. or higher. A method for producing polymethylsilsesquioxane particles.

_CH3Si ( ^OR1 ) ₃ (1)
(In formula (1) above, R ¹ represents an alkyl group having 1 to 4 carbon atoms, and multiple R ^1s may be the same or different.)

R ¹ may be linear or branched, and may be a methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group or tert-butyl group. mentioned. In the above formula (1), the plurality of R ¹ are preferably the same, and more preferably a methyl group or an ethyl group.

By using an amine having a boiling point of 50° C. or higher, the dispersibility of particles during the hydrolytic condensation reaction of the compound represented by the above formula (1) (hereinafter sometimes referred to as a monomer) can be improved, and the particle diameter can be reduced. It is thought that the CV value can be reduced. In addition, as described above, the monomer is a compound in which R ¹ is an alkyl group having 1 to 4 carbon atoms and has a small molecular weight, and aggregation during the hydrolytic condensation reaction is easily suppressed compared to a monomer with a high molecular weight. However, since highly volatile ammonia is used as a basic catalyst in Patent Document 1, the reaction product of the volatilized monomer and volatilized ammonia is added to the obtained polymethylsilsesquioxane particles. It is considered that it is mixed as an aggregate. However, in the present invention, since an amine having a boiling point of 50° C. or higher is used, it is possible to suppress the volatilized monomer from reacting with the amine to form an aggregate, thereby suppressing an increase in the CV value. In addition, the production method of the present invention also has the advantage of being able to reduce fouling of the upper portion of the reaction vessel due to the reaction product of the volatilized monomer and the volatilized basic catalyst.

Amines having a boiling point of 50° C. or higher may be used alone or in combination of two or more. The amine having a boiling point of 50°C or higher is preferably an amine having a boiling point of 80°C or higher, more preferably a boiling point of 100°C or higher, and still more preferably a boiling point of 150°C or higher. 400°C. Amines with a boiling point of 50° C. or higher can usually act as a basic catalyst. In the present invention, a basic catalyst other than an amine having a boiling point of 50°C or higher may be used together with an amine having a boiling point of 50°C or higher. The content of the amine having a boiling point of 50° C. or higher is more preferably 80% by mass or more, still more preferably 90% by mass or more, and may be 100% by mass. Moreover, the amine having a boiling point of 50° C. or higher preferably contains at least one amine having a pKa of 6 or higher. For amines having a boiling point of 50° C. or higher and a pKa of 6 or higher, the pKa is more preferably 6.5 or higher, still more preferably 7.0 or higher, particularly preferably 7.5 or higher, and the upper limit of the pKa is usually 12. A more preferred boiling point is 100°C or higher, and a more preferred boiling point is 150°C or higher, and the upper limit of the boiling point is usually 400°C.

Furthermore, among the basic catalysts, the basic catalyst having a pKa of more than 12 is preferably 10% by mass or less, more preferably 5% by mass or less, still more preferably 2% by mass or less, and 0% by mass. may be By doing so, polymethylsilsesquioxane particles having a number average particle size (1 nm or more and less than 100 nm) in the range described later can be produced at a high concentration.

Amines having a boiling point of 50° C. or higher include monobutylamine, monopentylamine, monohexylamine, monoheptylamine, monooctylamine, monononylamine, monodecylamine, monododecylamine, monotridecylamine, and monotetradecylamine. di-C _2-4 alkylamines such as diethylamine; tri-C _2-4 alkylamines such as triethylamine; NC _1-4 alkylalkanolamines such as N-methylethanolamine _. di-C _1-4 alkylalkanolamines such as dimethylaminoethanol; amino-C _2-4 alkylalkanolamines such as aminoethylethanolamine;
mono-C _2-4 alkanolamines such as monoethanolamine, monopropanolamine and monoisopropanolamine; di-C _2-4 alkanolamines such as diethanolamine and diisopropanolamine; tri-C 2-4 alkanolamines such as triethanolamine and triisopropanolamine
C _2-4 alkanolamine; (poly)ethyleneamines such as ethylenediamine, diethylenetriamine, triethylenetetramine and tetraethylenepentamine; ethyleneimine; polyethyleneimine; aminoethylpiperazine; aniline; Amines having a boiling point of 50° C. or higher include mono-C _4-14 alkylamines, di-C _2-4 alkylamines, tri-C _2-4 alkylamines, N--C _1-4 alkylalkanolamines and di-C ₁ Alkanolamines such as _-4 alkyl alkanolamine, amino C _2-4 alkyl alkanolamine, mono C _2-4 alkanolamine, di-C _2-4 alkanolamine, tri-C _2-4 alkanolamine are preferred, especially mono C 2-4 alkanolamine. _2-4 alkanolamines, di-C _2-4 alkanolamines or tri-C _2-4 alkanolamines are preferred.

Examples of the anionic surfactant include carboxylic acid type anionic surfactants such as aliphatic monocarboxylates, polyoxyethylene alkyl ether carboxylates, and fatty acid oils; dialkyl sulfosuccinates, polyoxyethylene alkyl sulfosuccinates sulfonic acid-type anionic surfactants such as acid salts, alkanesulfonates, straight-chain alkylbenzenesulfonates, branched-chain alkylbenzenesulfonates, naphthalenesulfonate-formaldehyde condensates, and alkylnaphthalenesulfonates; Sulfuric acid ester type anionic surfactants such as salts, polyoxyalkylene alkyl ether sulfates, oil sulfates, etc.; alkyl phosphates, alkyl phosphate ester salts, polyoxyethylene alkyl ether phosphates, polyoxyethylene alkyl aryl Phosphate ester type anionic surfactants such as ether phosphate; more preferred.

Specific examples of the anionic surfactant include polyoxyethylene styrenated ammonium phenyl ether sulfate, sodium polyoxyalkylene branched decyl ether sulfate (preferably sodium polyoxyethylene branched decyl ether sulfate), polyoxyethylene isodecyl Polyoxyethylene alkyl ethers such as ammonium ether sulfate, sodium polyoxyethylene tridecyl ether sulfate, sodium polyoxyethylene lauryl ether sulfate, ammonium polyoxyethylene lauryl ether sulfate, ammonium polyoxyethylene oleyl cetyl ether sulfate, and sodium polyoxyethylene oleyl cetyl ether sulfate Sulfate; polyoxyethylene tridecyl ether phosphate, polyoxyethylene lauryl ether phosphate/monoethanolamine salt, polyoxyethylene alkyl (C8) ether phosphate, polyoxyethylene alkyl (C8) ether phosphate - Polyoxyethylene alkyl ether phosphates such as monoethanolamine salts, polyoxyethylene alkyl (C12,13) ether phosphates, polyoxyethylene alkyl (C10) ether phosphates; polyoxyethylene lauryl ether sodium acetate, etc. polyoxyethylene alkyl ether carboxylate; polyoxyethylene alkyl sulfosuccinate such as polyoxyethylene lauryl ether disodium sulfosuccinate, polyoxyethylene alkyl (C12-14) disodium sulfosuccinate; polyoxyethylene styrenated phenyl Polyoxyethylene alkylaryl ether phosphates such as ether phosphates; Fatty acid oils such as sodium oleate and castor oil potassium; Alkyl sulfate ester salts such as sodium lauryl sulfate and ammonium lauryl sulfate; Alkyl benzene sulfones such as sodium dodecylbenzene sulfonate acid salts; alkylnaphthalenesulfonates; alkanesulfonates; dialkylsulfosuccinates; alkylphosphoric acid ester salts; naphthalenesulfonic acid-formaldehyde condensates;

Further, as the anionic surfactant, an oxyalkylene unit (-R ¹ O
-unit (R ¹ represents an alkylene group having 2 to 3 carbon atoms, preferably an ethylene group))
is preferably included. It becomes easier to make the particle size of the polymethylsilsesquioxane particles more uniform, and it becomes easier to make the obtained polymethylsilsesquioxane particles more spherical. Specifically, anionic interfaces containing oxyethylene units such as polyoxyethylene alkyl ether sulfates, polyoxyethylene alkyl ether phosphates, polyoxyethylene alkyl sulfosuccinates, polyoxyethylene alkyl aryl ether phosphates, etc. Activators are preferred, more preferably polyoxyethylene alkyl ether sulfates, more preferably polyoxyethylene styrenated phenyl ether sulfate ammonium salts, sodium polyoxyethylene alkyl ether sulfates, and ammonium polyoxyethylene alkyl ether sulfates.

The ratio of the amine having a boiling point of 50° C. or higher to 100 parts by mass of the monomer is preferably 0.3 parts by mass or more, more preferably 0.5 parts by mass or more, and still more preferably 1.0 parts by mass or more. , and preferably 5.0 parts by mass or less, more preferably 4.5 parts by mass or less, and even more preferably 4.0 parts by mass or less.

The ratio of the anionic surfactant to 100 parts by mass of the monomer is preferably 1.0 parts by mass or more, more preferably 3.0 parts by mass or more, and still more preferably 5.0 parts by mass or more, Also, it is preferably 20 parts by mass or less, more preferably 15 parts by mass or less, and still more preferably 10 parts by mass or less. When the amount of the anionic surfactant used is increased, the resulting polymethylsilsesquioxane particles tend to have a uniform particle size, and aggregation of the particles tends to be suppressed. Further, when the amount of the anionic surfactant used is suppressed, it becomes easier to reduce the foaming of the reaction liquid, and it becomes easier to suppress the formation of coarse particles.

In 100% by mass of the monomer hydrolysis-condensation reaction liquid containing water, an anionic surfactant, and a basic catalyst, the amount of the monomer charged is, for example, 5% by mass or more, preferably 10% by mass or more, It is more preferably 15% by mass or more, preferably 40% by mass or less, more preferably 35% by mass or less, and still more preferably 30% by mass or less.

The charge ratio of water to monomer (water/monomer) is preferably 5 or more, more preferably 7 or more, still more preferably 10 or more, and preferably 30 or less, more preferably 27 or less on a molar basis. , more preferably 25 or less.

In the production method of the present invention, the monomer, water, anionic surfactant and basic catalyst are all added to one reaction vessel, and the hydrolytic condensation reaction of the monomer may be performed, as long as the hydrolytic condensation reaction of the monomer can be performed. The order of addition is not particularly limited, but it is preferable to add the monomers to a liquid containing water, an anionic surfactant, and a basic catalyst.

The temperature of the hydrolysis-condensation reaction solution is preferably 30° C. or higher, more preferably 35° C. or higher. Methylsilsesquioxane particles are preferred because they can be produced at a high concentration. The temperature of the hydrolysis-condensation reaction solution is preferably less than 50°C, more preferably 45°C or less. Monomers are preferably added continuously (particularly by continuous dropwise addition) over a predetermined period of time. For example, it may be set to 60 minutes to 600 minutes, preferably 100 minutes to 480 minutes. After adding the total amount of the monomer, the temperature of the reaction solution may be raised to 50 to 70° C. (preferably 55 to 65° C.) and maintained for about 30 minutes to 5 hours. It can promote the hydrolytic condensation reaction of unreacted monomers.

The polymethylsilsesquioxane particles obtained by the production method of the present invention can have a number average particle diameter of 1 nm or more and less than 100 nm, and a coefficient of variation of the particle diameter of 40% or less. The number average particle diameter is preferably 5 nm or more, more preferably 10 nm or more, and preferably 90 nm or less, more preferably 70 nm or less, and still more preferably 50 nm or less. The coefficient of variation of the particle size is preferably 35% or less, more preferably 30% or less, particularly preferably 25% or less, and the lower limit is not particularly limited, but is usually about 3%. The number average particle diameter can be measured by light scattering particle size distribution of an aqueous dispersion of polymethylsilsesquioxane particles obtained by the production method of the present invention. In addition, the particle size of the polymethylsilsesquioxane particles can be measured by photographing the polymethylsilsesquioxane particles obtained by drying the aqueous dispersion using a scanning transmission electron microscope. The number average particle size of the primary particle size measured in this manner is, for example, 1 nm or more and less than 100 nm, preferably 5 nm or more, more preferably 10 nm or more, and preferably 90 nm or less, more preferably 70 nm. 50 nm or less, more preferably 50 nm or less. The coefficient of variation of the primary particle size is, for example, 3% or more and 40% or less, preferably 35% or less, more preferably 30% or less, and even more preferably 25% or less.

After obtaining an aqueous dispersion of polymethylsilsesquioxane particles by the production method of the present invention, it is preferable to replace with an organic solvent. Examples of the method of substituting with an organic solvent include a method of adding an organic solvent and distillation, a method of liquid separation, and a method of membrane separation. From the viewpoint of being able to remove the anionic surfactant, basic catalyst, etc. in the aqueous dispersion, a method by liquid separation treatment and a method by membrane separation are preferred. By substituting with an organic solvent to remove the anionic surfactant, basic catalyst, etc., the aggregation hardness of the dried polymethylsilsesquioxane particles can be lowered.

In the liquid separation method, it is preferable to use a water-immiscible organic solvent as the organic solvent. A water-immiscible organic solvent is added to the aqueous dispersion to extract the fine particles in the aqueous dispersion, and then allowed to stand still to extract the polymethylsilsesquioxane fine particles in the aqueous dispersion into the organic layer. At this time, the dispersion stabilizer exists in the water layer. Then, only the organic layer is separated to obtain a polymethylsilsesquioxane fine particle organic solvent dispersion.

The amount of the organic solvent to be added is usually 0.3 to 10 times, preferably 0.5 to 5 times the weight of water in the aqueous dispersion. The extraction time is not particularly limited as long as the fine particles in the aqueous layer are extracted into the organic layer.
Water-immiscible organic solvents include benzene, toluene, xylene, monochlorobenzene, dichlorobenzene, n-butanol, cyclohexanol, benzyl alcohol, phenol, cresol, anisole, acetal, ethyl acetate, propyl acetate, butyl acetate, methyl ethyl ketone, methyl Examples include isobutyl ketone, hexane, heptane, cyclohexane, chloroform, and dichloromethane, with ethyl acetate being particularly preferred. These solvents may be used alone or in combination of two or more.

In the method of membrane separation, the aqueous dispersion is subjected to a membrane with a pore size of about 0.001 to 0.01 μm (ultrafiltration membrane, etc.), a membrane with a pore size of 0.002 μm or less (nanofiltration membrane, reverse osmosis membrane, etc.), etc. is preferably used for purification, and ultrafiltration is preferred from the viewpoint of purification efficiency. Membrane separation (membrane filtration) can separate fine polymethylsilsesquioxane particles from the anionic surfactant, basic catalyst, etc. used in the hydrolytic condensation reaction. The shape of the separation membrane is not particularly limited, and includes flat membrane, hollow fiber, tubular, spiral and monolithic shapes, with hollow fiber, tubular and monolithic shapes being preferred.

As a dispersion medium for ultrafiltration, for example, water, an alcoholic solvent, or a mixed solvent of water and an alcoholic solvent is preferable. Examples of the alcohol include methanol, ethanol, propanol, 2-propanol, butanol, 2-butanol, isobutyl alcohol, pentanol, methylbutanol, neopentyl alcohol, isopentyl alcohol, hexanol, 2-hexanol, heptanol, 2- Heptanol, octanol, 2-octanol, cyclohexanol and methylcyclohexanol can be mentioned, and methanol is particularly preferred. These solvents may be used alone or in combination of two or more.

The polymethylsilsesquioxane particles can be isolated as powder by drying the organic solvent dispersion of the polymethylsilsesquioxane particles and, if necessary, pulverizing. The drying method is preferably spray drying from the viewpoint of reducing the aggregation hardness of the polymethylsilsesquioxane particles, but heat drying (stirring heat drying, stationary heat drying, etc.) is preferably performed in a mixer such as a conical ribbon mixer. Drying by stirring and heating in a furnace, and drum-type drying such as a drum dryer) are also possible. Since the polymethylsilsesquioxane particles are dispersed in an organic solvent, the bonding between the particles during drying is reduced. Don't overdo it. Examples of crushing methods include jet mills such as impact plate mills, rotary mechanical mills and the like, and mechanical pulverizers.

Moreover, the polymethylsilsesquioxane particles (dry powder) obtained by the production method of the present invention can be made highly hydrophobic. Specifically, the degree of hydrophobicity can be evaluated by the degree of hydrophobicity measured according to the method of Examples described later or the weight loss rate when TG-DTA is measured. The degree of hydrophobicity of the polymethylsilsesquioxane particles obtained by the production method of the present invention is preferably 35% or more, more preferably 36% or more, still more preferably 37% or more, and the upper limit is particularly Although not limited, it is usually about 50%. Thus, highly hydrophobic polymethylsilsesquioxane particles can be used as a toner external additive and are effective in improving fluidity. In addition, the heat weight loss change rate from room temperature to 400 ° C. measured according to the method of the examples described later is preferably 2.2% or less, more preferably 2.0% or less, and still more preferably 1 .8% or less.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to Examples. The present invention is not limited by the following examples, and it is of course possible to make appropriate modifications within the scope that can be adapted to the spirit of the above and the following. Included in scope.

Various physical properties were measured and evaluated by the following methods.

(1) Measurement of number average particle size and coefficient of variation (CV value) of polymethylsilsesquioxane particles (1-1) Measurement by light scattering particle size distribution Polymethylsilsesquioxane obtained in Examples and Comparative Examples An aqueous dispersion of particles (an aqueous dispersion after filtering the reaction solution with a 300-mesh and 3 μm membrane membrane in the examples described later) was fixed at a filter position of 280, and ion-exchanged water was added so that the scattering intensity was 300 kHz. and measured with a light scattering particle size distribution analyzer (manufactured by Particle Sizing Systems, "Nicomp MODEL380") to determine the number average particle size. Also, the standard deviation was calculated based on the number average particle size obtained by the above apparatus, and the coefficient of variation (CV value: %) was obtained from the following formula.
Variation coefficient (CV value: %) = 100 x (standard deviation / number average particle size)

(1-2) Measurement by Scanning Transmission Electron Microscope An aqueous dispersion of polymethylsilsesquioxane particles obtained in Example 1 described below was put on a collodion membrane and dried, and then a scanning transmission electron microscope was used. The polymethylsilsesquioxane particles were photographed at a magnification of 200,000. Randomly select 100 polymethylsilsesquioxane particles from the obtained image, measure the primary particle diameter of each using the vernier caliper calculation tool attached to the device, and take the average value of the measured values as the number average particle diameter. bottom.
The standard deviation was calculated based on the number average particle size of the primary particles obtained by the above method, and the coefficient of variation (CV value: %) was obtained from the following formula.
Variation coefficient (CV value: %) = 100 x (standard deviation / number average particle size of primary particles)

(2) Confirmation of Aggregates Aqueous dispersions of polymethylsilsesquioxane particles obtained in Examples and Comparative Examples (synonymous with the aqueous dispersion to be measured in (1) above) were subjected to 300 mesh (JIS mesh). After filtration using a wire mesh, the solution was filtered through a 3 μm membrane membrane and the degree of formation of aggregates was visually evaluated according to the following criteria.
Good: No aggregates on the membrane after filtration, or there are aggregates but no clogging.
x: Clogging occurred in the membrane after filtration.

(3) Measurement of Hydrophobicity of Dry Powder of Polymethylsilsesquioxane Particles Add 50 mL of water to a glass beaker with a capacity of 200 mL with a stirrer at the bottom, and add the water obtained in Examples 1 and 2 to the surface of the water. After gently placing 0.2 g of dry powder (1) or (2) of polymethylsilsesquioxane particles, the stirrer was gently rotated so that the water surface was not rippling. After that, the tip of the burette was inserted into the water in the beaker, and methanol was gradually introduced into the water through the burette. This introduction was continued until it was possible to visually confirm that all the particles on the surface of the water had sunk, and the hydrophobization degree was evaluated according to the following formula.
Degree of hydrophobicity (%) = introduced amount of methanol / (amount of water + introduced amount of methanol) x 100

(4) Simultaneous differential thermal thermogravimetric measurement (TG-DTA) of dry powder of polymethylsilsesquioxane particles
Using a differential thermal thermogravimetric analyzer (TG-DTA), dry powder (1) of polymethylsilsesquioxane particles of Example 1 was heated from room temperature to 500°C at a temperature elevation rate of 10°C/min under a nitrogen atmosphere. C., and the thermogravimetric loss rate up to 400.degree. C. was measured.

(5) Toner Fluidity 50 parts of a toner having an average particle size of 10 μm in which carbon black is dispersed as a coloring agent in a binder resin made of a styrene-n-butyl acrylate copolymer, and a dry powder of polymethylsilsesquioxane particles. 0.5 part of the toner was uniformly mixed at room temperature with a mixer (“Labo Milser LM-PLUS” manufactured by Iwatani Corporation) at a peripheral speed of 20 m/s (rotational speed of 6,000 rpm) for 90 seconds to obtain a toner composition. got stuff
Using a powder tester (registered trademark) (PT-E type, manufactured by Hosokawa Micron Corporation), sieves with openings of 150 μm, 100 μm, and 45 μm (plain weave wire mesh, standard JIS Z8801-1) were vibrated for 10 seconds at an intensity of 4.0. After the toner composition was sieved, the remaining amount of the toner composition on each sieve was measured, and the fluidity index was calculated using the following formula. A smaller fluidity index indicates that a toner composition with better fluidity can be obtained.
Fluidity index (%) = [(A + 0.6 x B + 0.2 x C) / weight of measurement sample] x 100
A: Remaining amount (g) of toner composition on a sieve with an opening of 150 μm
B: Remaining amount of toner composition on a 100 μm sieve (g)
C: Remaining amount (g) of toner composition on a sieve with an opening of 45 μm

Example 1-1
622.5 parts by weight of deionized water and 1.40 parts by weight of monoethanolamine (MEA, boiling point: 170°C, pKa = 9.5) were added to a glass reaction vessel equipped with a stirrer, thermometer, dropping port, and cooler. part, triethanolamine (TEA, boiling point: 335 ° C., pKa = 7.8) 3.42 parts by mass, polyoxyethylene alkyl ether sulfate salt as an aqueous solution of anionic surfactant (Nippon Nyukazai Co., Ltd., New Cole 1305 -SN) was added, and the mixture was stirred at room temperature until uniform. Then, 201.2 parts by mass of methyltrimethoxysilane (hereinafter referred to as “MTMS”) was added dropwise from the dropping port over 120 minutes while stirring at 40° C., and polymethylsilsesquioxane particles precipitated. After the entire amount of MTMS was added dropwise, the reaction solution was heated to 60° C. and aged at 60° C. for 1 hour. After that, the reaction solution was cooled and filtered through a 300-mesh filter, and dispersion stability was evaluated by filtering with a 3 μm membrane membrane, and an aqueous dispersion in which polymethylsilsesquioxane particles were dispersed was obtained. Table 1 shows the number-average particle size, coefficient of variation, and agglomerate measured by light scattering particle size distribution of the obtained polymethylsilsesquioxane particles.
In addition, the number of primary particles of the polymethylsilsesquioxane particles obtained in Example 1 measured by scanning transmission electron microscopy as described in "(1-2) Scanning transmission electron microscopy" above. The average particle size was 18.0 nm and the CV value was 19.5%.

This aqueous dispersion of polymethylsilsesquioxane particles was concentrated with an ultrafiltration module (manufactured by Asahi Kasei Chemicals Corp., Microza UF), and the solvent was replaced while adding methanol as appropriate. % polymethylsilsesquioxane particle methanol dispersion was obtained. After that, it was dried by heating at 40° C. for 2 hours and pulverized for 90 seconds with a labo miller (LM-PLUS) to obtain dry powder (1-1) of polymethylsilsesquioxane particles.

Example 1-2
After obtaining an aqueous dispersion of polymethylsilsesquioxane particles in the same manner as in Example 1-1, liquid separation treatment was performed instead of ultrafiltration. That is, 100.0 parts by mass of the aqueous dispersion of polymethylsilsesquioxane particles obtained in Example 1-1 was added to a glass beaker, and then 50.0 parts by mass of ethyl acetate was added, followed by stirring and rotating with a stirrer. The mixture was stirred for 2 hours at room temperature at several 200 rpm. The resulting milky white suspension was transferred to a separating funnel and allowed to stand at room temperature for 24 hours to separate the aqueous layer into the upper layer and the ethyl acetate into the lower layer, and the polymethylsilsesquioxane particles migrated to the lower layer. I confirmed that The ethyl acetate dispersion of polymethylsilsesquioxane particles in the lower layer was separated, dried by heating at 60° C. for 2 hours, and pulverized for 90 seconds with a laboratory miller (LM-PLUS) to obtain a dry powder of polymethylsilsesquioxane particles. (1-2) was obtained.

Example 2
In the same manner as in Example 1-1, except that 6.84 parts by mass of triethanolamine (TEA) was added without adding monoethanolamine (MEA), and the dropping time of MTMS was set to 360 minutes. An aqueous dispersion of methylsilsesquioxane particles and a dry powder (2) were obtained.

Example 3
An aqueous dispersion of polymethylsilsesquioxane particles was prepared in the same manner as in Example 1-1, except that 6.84 parts by mass of triethanolamine (TEA) was added without adding monoethanolamine (MEA). and dry powder (3) was obtained.

Comparative example 1
Polymethylsilsesquioxane was prepared in the same manner as in Example 1-1, except that monoethanolamine (MEA) and triethanolamine (TEA) were not added and 3.22 parts by mass of 25% aqueous ammonia was added. An aqueous dispersion of particles was obtained. The boiling point of ammonia is about -33°C.

Table 1 shows the results of Examples and Comparative Examples.

From Table 1, in Examples 1-1, 2, and 3 using an amine having a boiling point of 50° C. or higher, the particle diameter C
While it was possible to obtain polymethylsilsesquioxane particles with a reduced V value, in Comparative Example 1 using ammonia having a boiling point of less than 50 ° C., the CV value of the particle diameter exceeded 40%. It can be seen that In addition, in Examples 1-1, 2 and 3, the degree of aggregate formation was also evaluated as ◯.

In addition, the dry powder (1-1) obtained in Example 1-1 had a hydrophobicity of 41.3%, and a heat weight loss rate up to 400 ° C. was 1.8%. The degree of hydrophobicity of the dry powder (2) obtained in 2 was 38.8%, indicating that the polymethylsilsesquioxane particles of Examples 1-1 and 1-2 are highly hydrophobic. The fluidity index of the toner composition prepared using the dry powder (1-1) of Example 1-1 was 55.0%, and the dry powder (1-1) obtained in Example 1-2 had a flow index of 55.0%. The fluidity index of the toner composition prepared using 2) was 56.0%, and all of them exhibited a good fluidity index of 60% or less.

The polymethylsilsesquioxane particles obtained by the production method of the present invention have a small particle size and a reduced CV value. For this reason, for example, anti-blocking agents and slipperiness imparting agents for various films such as polyolefin films, polyester films, polyimide films and fluororesin films; coating agents for polymeric materials such as various films and molded bodies, or additives for coating agents Agents; Modifiers for viscosity, thixotropy, viscoelasticity, strength, etc. of various resins; In-plane spacers for liquid crystal display elements, seal part spacers for liquid crystal display elements, spacers for EL display elements, spacers for touch panels, ceramics and plastics spacers such as gap holding agents between various substrates; sealing materials for semiconductors, sealing materials for liquid crystals, sealing materials for various electronic parts such as sealing materials for LED light emitting elements; light diffusing agents such as light plates and antiglare films; cosmetic additives such as white extender pigments; dental materials; It is possible to apply to the usage.

Claims (2)

A method for producing polymethylsilsesquioxane particles by hydrolyzing and condensing a compound represented by the following formula (1) in the presence of water, an anionic surfactant, and an amine having a boiling point of 50° C. or higher.
_CH3Si ( ^OR1 ) ₃ (1)
(In formula (1) above, R ¹ represents an alkyl group having 1 to 4 carbon atoms, and multiple R ^1s may be the same or different.) The production method according to claim 1, wherein the amine having a boiling point of 50°C or higher includes at least one amine having a pKa of 6 or higher.