JP7091193B2 - Polymethylsilsesquioxane particles and toner external additives - Google Patents

Description

The present invention relates to polymethylsilsesquioxane particles that can be used as a toner external additive or the like.

Toners used in developing agents used in electrocameras, copiers, printers, etc. include organic particles and inorganic particles in order to improve the fluidity, chargeability, and cleaning properties of photosensitive drums. Toner is added.
As the inorganic particles, those made of an inorganic material such as silica, titania or alumina are used (Patent Documents 1 and 2), and the use of polymethylsilsesquioxane powder is also proposed (Patent Document 3). ..

Japanese Unexamined Patent Publication No. 7-92722 Japanese Unexamined Patent Publication No. 11-65165 JP-A-2017-214503

Although the polymethylsilsesquioxane particles show an excellent fluidity improving effect as compared with conventional silica particles and the like, it is desirable to show a further excellent fluidity improving effect. The present invention has been made by paying attention to the above circumstances, and an object thereof is polymethylsilsesqui, which can exhibit a further excellent fluidity improving effect when used as an external additive for toner. The purpose is to provide oxane particles.

As a result of intensive studies to solve the above problems, the present inventors have found that increasing the degree of hydrophobicity of polymethylsilsesquioxane particles exhibits a further excellent fluidity improving effect, and the present invention has been made. Was completed.
That is, the present invention is as follows.
[1] Polymethylsilsesquioxane particles having a degree of hydrophobicity of 15% or more and an average number of primary particle diameters of 0.001 μm or more and 0.10 μm or less.
[2] The polymethylsilsesquioxane particles according to [1], which contain a quaternary ammonium salt.
[3] A toner external preparation composed of the polymethylsilsesquioxane particles according to [1] or [2].
[4] Water of polymethylsilsesquioxane particles is obtained by hydrolyzing and condensing a trifunctional organic silicon monomer represented by the formula (2) in the presence of water, a base catalyst, and an anionic surfactant. Prepare a dispersion and
A method for producing polymethylsilsesquioxane particles, in which the aqueous dispersion is membrane-separated and then dried.
CH ₃ Si (OR ² ) ₃ ... (2)
[In the formula (2), R ² represents an alkyl group having 1 to 6 carbon atoms, and a plurality of R ² may be different from each other. ]

According to the present invention, since the degree of hydrophobicity of the polymethylsilsesquioxane particles is increased, a further excellent fluidity improving effect is exhibited.

1. 1. Polymethylsilsesquioxane particles The polymethylsilsesquioxane particles of the present invention have a small primary particle diameter, and the average number thereof is 0.001 μm or more, preferably 0.005 μm or more, and more preferably 0. It is .007 μm or more, 0.10 μm or less, preferably 0.080 μm or less, more preferably 0.050 μm or less, and most preferably 0.04 μm or less. Polymethylsilsesquioxane particles having a primary particle size in this range can exhibit excellent properties when used as a toner externalizing agent, specifically because the primary particle size is not too small. The surface of each toner particle is covered with many polymethylsilsesquioxane particles because the cohesive force between them is not excessive and the coagulation is moderately eliminated when the toner powder is dry-mixed and the primary particle size is not too large. It is possible to increase the fluidity of the toner.

For the average number of primary particle diameters of dried polymethylsilsesquioxane particles, it is ideal to disperse the particles in an appropriate medium in the form of primary particles and measure the average number of the particles in this dispersion. However, electron micrographs of polymethylsilsesquioxane particles may be taken to measure the diameter of each particle and statistically processed. Further, as long as the particles are dispersed in the state of the primary particles and the size of the primary particles does not change thereafter, a dry powder of the polymethylsilsesquioxane particles (hereinafter, may be referred to as “polymethylsilsesquioxane powder”) is obtained. The number average particle size may be measured in the state of the previous dispersion, and the value may be adopted as the number average particle size of the polymethylsilsesquioxane particles (polymethylsilsesquioxane powder). In the present specification, when the polymethylsilsesquioxane is described by focusing on its properties as particles, it is referred to as "polymethylsilsesquioxane particles", and when it is described in consideration of its dry state, it is referred to as "polymethylsilsesquioxane particles". It is called "polymethylsilsesquioxane powder".

The coefficient of variation of the primary particle size of the polymethylsilsesquioxane particles is preferably 50% or less, more preferably 40% or less, further preferably 30% or less, and smaller is preferable, but the lower limit is, for example, 2. %, 10%, or 15% is also acceptable. When the coefficient of variation is within the above range, the adhesion of the polymethylsilsesquioxane particles forms convex portions of uniform height on the surface of the toner particles, so that the adhesion between the toner particles is suppressed. The fluidity of the toner is improved. The coefficient of variation of the primary particle size is a value represented by the following formula.
Coefficient of variation of primary particle size (%) = (standard deviation of primary particle size / average number of primary particle size) x 100

The degree of hydrophobization of the polymethylsilsesquioxane particles is 15% or more, preferably 20% or more, and more preferably 25% or more. Increasing the degree of hydrophobization can further improve the fluidity of the toner when the polymethylsilsesquioxane particles are dry-mixed with the toner powder. The upper limit of the degree of hydrophobicity is, for example, 50% or less, preferably 45% or less, and more preferably 40% or less. Good results can be obtained even if the degree of hydrophobization is 37% or less. As the degree of hydrophobicity increases, the amount of charge becomes excessive and it becomes difficult to stabilize the amount of charge.

The content of the anionic surfactant in the polymethylsilsesquioxane particles is preferably 1.0% by mass or less, more preferably 0.75% by mass or less, still more preferably 0.5% by mass. % Or less. By reducing the content of the anionic surfactant, the degree of hydrophobicity of the particles can be set in an appropriate range. The lower limit of the content of the anionic surfactant is not particularly limited and may be 0% by mass, but may be 0.01% by mass or more. Specific examples of the anionic surfactant will be described later. When a plurality of anionic surfactants are contained, the total amount thereof is preferably in the above range. The anionic surfactant may be used in the process of producing polymethylsilsesquioxane particles, and its content can be reduced, for example, by removing it by membrane separation.

The polymethylsilsesquioxane particles preferably contain a quaternary ammonium salt. If the fluidity of the toner is increased, the amount of charge may increase excessively, but by including the quaternary ammonium salt in the polymethylsilsesquioxane particles, the fluidity of the toner is maintained. The amount of charge can be appropriately stabilized. Examples of the quaternary ammonium salt include tetraalkylammonium salt, trialkylarylammonium salt, dialkyldiarylammonium salt, alkyltriarylammonium salt, tetraarylammonium salt, cyclic ammonium salt, dicyclicammonium salt and the like. Ammonium salts are preferred.

Examples of the tetraalkylammonium salt include short chains such as tetramethylammonium salt, tetraethylammonium salt, tetrapropylammonium salt, dimethyldibutylammonium salt, tetrabutylammonium salt, tetrapentylammonium salt, and tetrahexylammonium salt (having 1 to 1 to carbon atoms). Those having four alkyl groups (about 6); short-chain alkyl groups such as lauryltrimethylammonium salt, stearyltrimethylammonium salt, cetyltrimethylammonium salt, distearyldimethylammonium salt and medium- or long-chain (7 to 30 carbon atoms). (Degree), those having an alkyl group, and those having four short-chain alkyl groups are preferable.

Examples of the anion-forming component of the quaternary ammonium salt include halogen ions such as ^{Cl- and} Br-; methanesulphonic acid anion (CH ₃ SO _3- ⁾ and toluene sulphonic acid anion (CH ₃ ^- Ph-SO _3-- ). ) And other organic sulfonic acid ions; SO _{4-, (1/2) SO 4 2-} ^and other sulfate ions, and the ^like , and halogen ions are preferable.

2. 2. Method for Producing Polymethylsilsesquioxane Particles 2.1 Particleification by Hydrolysis Condensation Reaction The polymethylsilsesquioxane particles are hydrolyzed and condensed with a trifunctional organic silicon monomer represented by the formula (2). Can be manufactured.
CH ₃ Si (OR ² ) ₃ ... (2)
[In the formula (2), R ² represents an alkyl group having 1 to 6 carbon atoms, and a plurality of R ^2s are preferably the same, but may be different from each other. ]

The alkyl group of R ² may be linear, branched or cyclic, and may be, for example, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, an isobutyl group or sec-. Examples thereof include a butyl group, a tert-butyl group, a pentyl group, a hexyl group, a cyclopentyl group, a cyclohexyl group and the like. The carbon number of R ² is preferably 1 to 3, more preferably 1 to 2.

Examples of the monomer of the formula (2) include methyltrimethoxysilane, methyltriethoxysilane, methyltripropoxysilane, methyltriisopropoxysilane, and the like, and these may be used alone or in combination of two or more. can.

The hydrolysis and condensation of the monomer of the formula (2) may be appropriately adopted by a known method, but it is preferably carried out in the presence of water, a base catalyst and an anionic surfactant (aspect 1), and the formula (aspect 1) is preferable. A hydrolyzed solution (a) containing a hydrolyzate of the monomer of 2), water and an anionic surfactant (s1), and a precipitate solution (b) containing water, a basic catalyst and an anionic surfactant (s2). (Aspect 2) is more preferable by condensing by a method including a step of mixing. In the first aspect, the condensation occurs in the presence of the anionic surfactant, and in the second aspect, both the hydrolysis liquid (a) and the precipitation liquid (b) contain the anionic surfactant, so that the hydrolysis is performed. When the liquid (a) and the precipitation liquid (b) are mixed, the reaction liquid can be easily mixed uniformly, and the condensation reaction of the hydrolyzate of the monomer of the formula (2) can easily proceed uniformly. As a result, the polymethylsilsesquioxane particles can be produced with a uniform particle size, the dispersion stability of the polymethylsilsesquioxane particles is improved, and aggregation can be prevented. Hereinafter, the second aspect of mixing the hydrolyzed solution (a) and the precipitate (b) will be described in more detail, but the description other than the addition procedure (for example, specific examples of the added components, the amount of the added component, etc.) will be described in the first aspect. Can be applied to the explanation of.

The hydrolyzate of the monomer of the formula (2) is a compound containing -OH (silanol group) formed by hydrolysis of -OR ² , and is CH ₃ Si (OR ² ) ₂ (OH), CH ₃ Si. Examples thereof include (OR ² ) (OH) ₂ , CH ₃ Si (OH) ₃ , and the like, and it is preferable that CH ₃ Si (OH) ₃ is contained. Further, the hydrolyzate of the monomer of the formula (2) is a compound in which a part of —OH (silanol group) contained in the hydrolyzate is condensed to form a Si—O—Si bond (hereinafter, “”. It may be referred to as "partial condensate"). Even if a part of -OH (silanol group) contained in the hydrolyzate is condensed, the reaction is uniform because the hydrolyzed solution (a) and the precipitate solution (b) contain anionic surfactant. You can proceed to.

In the hydrolyzed solution (a), the molar concentration of silicon atoms contained in the hydrolyzate of the monomer of the formula (2) is preferably 0.1 mmol / g or more, more preferably 1 mmol / g or more, still more preferably. Is 2 mmol / g or more, preferably 10 mmol / g or less, more preferably 7 mmol / g or less, still more preferably 5 mmol / g or less.

Examples of the anionic surfactant (s1) include carboxylic acid-type anionic surfactants such as aliphatic monocarboxylates, polyoxyethylene alkyl ether carboxylates, and fatty acid oils; dialkyl sulfosulfates, polyoxyethylene. Sulfonic acid type anionic surfactants such as alkyl sulfosulfate, alkane sulfonate, linear alkyl benzene sulfonate, branched chain alkyl benzene sulfonate, naphthalene sulfonate-formaldehyde condensate, alkyl naphthalene sulfonate; Sulfonate-type anionic surfactants such as alkyl sulfates, polyoxyalkylene alkyl ether sulfates, oil and fat sulfates; alkyl phosphates, alkyl phosphates, polyoxyethylene alkyl ether phosphates, polyoxy Phosphate ester type anionic surfactants such as ethylene alkylaryl ether phosphate; and the like; sulfonic acid type anionic surfactants, sulfate ester type anionic surfactants are preferable, and sulfate ester type anionic interfaces are preferable. Activators are more preferred.

Specific examples of the anionic surfactant (s1) include polyoxyethylene styrenated phenyl ether ammonium sulfate, polyoxyalkylene branched decyl ether sulfate sodium (preferably polyoxyethylene branched decyl ether sulfate sodium), and polyoxyethylene. Polyoxyethylene such as isodecyl ether ammonium sulfate, polyoxyethylene tridecyl ether sodium sulfate, polyoxyethylene lauryl ether sulfate sodium, polyoxyethylene lauryl ether ammonium sulfate, polyoxyethylene oleylcetyl ether ammonium sulfate, polyoxyethylene oleylcetyl ether sulfate sodium Alkyl ether sulfate; polyoxyethylene tridecyl ether phosphate ester, polyoxyethylene lauryl ether phosphate ester / monoethanolamine salt, polyoxyethylene alkyl (C8) ether phosphate ester, polyoxyethylene alkyl (C8) ether phosphorus Polyoxyethylene alkyl ether phosphates such as acid ester monoethanolamine salts, polyoxyethylene alkyl (C12,13) ether phosphate esters, polyoxyethylene alkyl (C10) ether phosphate esters; polyoxyethylene lauryl ether acetate Polyoxyethylene alkyl ether carboxylate such as sodium; polyoxyethylene lauryl ether sulfosulfate disodium, polyoxyethylene alkyl (C12-14) sulfosulfate disodium or the like polyoxyethylene alkyl sulfosulfate; polyoxy Polyoxyethylene alkylaryl ether phosphates such as ethylene styrene pheniether phosphite; fatty acid oils such as sodium oleate and potash oil; alkyl sulfates such as sodium lauryl sulphate and ammonium lauryl sulphonate; sodium dodecylbenzene sulphonic acid Alkylbenzene sulfonates such as; alkylnaphthalene sulfonates; alkane sulfonates; dialkyl sulfosulfates; alkyl phosphate ester salts, naphthalene sulfonic acid-formaldehyde condensates, and the like.

Further, as the anionic surfactant (s1), an oxyalkylene unit (-R ³ O- unit (R ³ represents an alkylene group having 2 to 3 carbon atoms, preferably an ethylene group) in the molecule). ) 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 closer to a spherical shape. Specifically, an anionic interface containing oxyethylene units such as polyoxyethylene alkyl ether sulfate, polyoxyethylene alkyl ether phosphate, polyoxyethylene alkyl sulfosulfate, and polyoxyethylene alkyl aryl ether phosphate. The activator is preferable, the polyoxyethylene alkyl ether sulfate is more preferable, and the polyoxyethylene styrene phenyl ether sulfate ester ammonium salt, the polyoxyethylene alkyl ether sodium sulfate, and the polyoxyethylene alkyl ether sulfate ammonium are further preferable.

The content of the anionic surfactant (s1) is preferably 0.1 part by mass or more, more preferably 0.1 part by mass with respect to 100 parts by mass of the monomer of the formula (2) used in the hydrolysis liquid (a). It may be 1 part by mass or more, more preferably 3 parts by mass or more, particularly preferably 5 parts by mass or more, further 10 parts by mass or more, preferably 50 parts by mass or less, and more preferably 30 parts by mass. Parts or less, more preferably 20 parts by mass or less.
When the amount of the anionic surfactant used is increased, the particle size of the polymethylsilsesquioxane particles tends to be uniform, and the aggregation of the polymethylsilsesquioxane particles tends to be suppressed. Further, when the amount of the anionic surfactant used is suppressed, it becomes easy to reduce the foaming of the reaction solution, and it becomes easy to suppress the formation of coarse particles.

The hydrolysis solution (a) preferably further contains an acid catalyst. When the hydrolyzed solution (a) contains an acid catalyst, it becomes easy to control the hydrolysis reaction of the monomer of the formula (2) and its hydrolyzate. As the acid catalyst contained in the hydrolysis liquid (a), either an organic acid or an inorganic acid can be used, and an aqueous solution thereof is preferably used. Specifically, examples of organic acids include formic acid, acetic acid, propionic acid, oxalic acid, and citric acid, and examples of inorganic acids include hydrochloric acid, sulfuric acid, nitrate, and phosphoric acid, which are easily available and easy to handle. Organic acids are preferable, and acetic acid is particularly preferable.
When the hydrolyzed solution (a) contains an acid catalyst, the content thereof is preferably 0.001 mol or more with respect to 100 mol of silicon atoms contained in the hydrolyzate of the monomer of the formula (2). , More preferably 0.01 mol or more, preferably 0.5 mol or less, more preferably 0.3 mol or less, still more preferably 0.1 mol or less.

The pH of the hydrolyzed solution (a) is preferably 2.0 or more, more preferably 2.5 or more, still more preferably 3.0 or more, and preferably 5.5 or less, more preferably. Is 4.5 or less, more preferably 4.0 or less.

The charging ratio of water used in the hydrolyzed solution (a) to the monomer of the formula (2) (water / monomer of the formula (2)) is preferably 2 or more, more preferably 4 or more on a molar basis. It is more preferably 6 or more, preferably 20 or less, more preferably 15 or less, still more preferably 10 or less.

The hydrolyzed solution (a) may contain alcohol (R ² OH). Examples of the alcohol include a group in which -OH is bonded to the group exemplified as R ² .
The alcohol content is preferably 10% by mass or more, more preferably 20% by mass or more, still more preferably 30% by mass or more, and 50% by mass or less in 100% by mass of the hydrolyzed liquid (a). It is preferably 40% by mass or less, still more preferably 37% by mass or less.

The total content of the hydrolyzate of the monomer of the formula (2), water, the acid catalyst used as needed, the anionic surfactant (s1), and the alcohol contained as needed is water. The decomposition liquid (a) is preferably 80% by mass or more, more preferably 90% by mass or more, still more preferably 95% by mass or more, and particularly preferably 99% by mass or more in 100% by mass.

The hydrolyzed solution (a) can be produced by mixing the monomer of the formula (2), water, the anionic surfactant (s1), and an acid catalyst used as needed. By hydrolyzing the monomer of the formula (2) using an acid catalyst, the hydrolysis reaction can easily proceed uniformly.

The temperature at which the monomer of the formula (2), water, the anionic surfactant, and the acid catalyst used as needed are mixed is preferably 0 ° C. or higher, more preferably 10 ° C. or higher, still more preferable. Is 15 ° C. or higher, preferably 80 ° C. or lower, more preferably 50 ° C. or lower, still more preferably 40 ° C. or lower.
The time for mixing the monomer of the formula (2), water, the anionic surfactant (s1), and the acid catalyst used as needed is preferably 10 minutes or more, more preferably 20 minutes. As mentioned above, it is more preferably 30 minutes or more, preferably 200 minutes or less, more preferably 120 minutes or less, still more preferably 90 minutes or less.

The precipitate (b) contains water, a base catalyst and an anionic surfactant (s2). By using a base catalyst for the precipitate (b), the rate of the condensation reaction can be increased.
Examples of the base catalyst include metal hydroxides (preferably alkali metal hydroxides) such as lithium hydroxide, sodium hydroxide and potassium hydroxide; amines such as ammonia, monomethylamine and dimethylamine; Among them, amines are preferable, and ammonia is particularly preferable, because impurities that limit the use of the produced polymethylsilsesquioxane particles can be reduced and removal from the particles is easy.

The content of the base catalyst contained in the precipitate (b) is 0.01 mol or more with respect to 100 mol of silicon atoms contained in the hydrolyzate of the monomer of the formula (2) in the hydrolysis solution (a). It is preferably 0.05 mol or more, further preferably 0.1 mol or more, particularly preferably 1 mol or more, preferably 20 mol or less, and more preferably 15 mol. It is mol or less, more preferably 10 mol or less.

The pH of the precipitate (b) is preferably 8.0 or more, more preferably 8.5 or more, still more preferably 9.0 or more, and preferably 13.0 or less. It is more preferably 12.5 or less, still more preferably 12.0 or less.

The anionic surfactant (s2) may be the same as or different from the anionic surfactant (s1), and examples thereof include compounds similar to those exemplified as the anionic surfactant (s1). Of these, sulfonic acid-type anionic surfactants and sulfate ester-type anionic surfactants are preferable, and sulfate ester-type anionic surfactants are more preferable.

Further, the anionic surfactant (s2) may contain -R ³ O-units (R ³ represents an alkylene group having 2 to 3 carbon atoms, preferably an ethylene group) in the molecule. preferable. It becomes easier to make the particle size of the polymethylsilsesquioxane particles more uniform.

The content of the anionic surfactant (s2) is preferably 0.001% by mass or more, more preferably 0.005% by mass or more, and further preferably 0. It may be 01% by mass or more, particularly preferably 0.1% by mass or more, further may be 0.2% by mass or more, preferably 5% by mass or less, more preferably 1% by mass or less, and further. It is preferably 0.5% by mass or less.

By mixing the hydrolyzed solution (a) and the precipitate solution (b), the condensation reaction of the —OH group (silanol group) contained in the hydrolyzate of the monomer of the formula (2) proceeds, and Si— O-Si bonds are formed and polymethylsilsesquioxane particles are formed. Since both the hydrolyzed liquid (a) and the precipitate liquid (b) contain anionic surfactant, it is easy to mix uniformly from the beginning of mixing, and the condensation reaction proceeds evenly, probably because the particles. It is possible to obtain polymethylsilsesquioxane particles having a uniform diameter. The obtained polymethylsilsesquioxane particles are usually in a dispersed state in the reaction solution.

In the mixing of the hydrolysis liquid (a) and the precipitate liquid (b), a procedure is adopted in which the particle size of the produced polymethylsilsesquioxane particles can be uniformly controlled and the particles can be prevented from agglomerating with each other. A method of continuously dropping the decomposition liquid (a) onto the precipitate liquid (b) is preferable. When the hydrolyzed solution (a) is continuously dropped, the dropping time is preferably 10 minutes to 300 minutes, more preferably 30 minutes to 200 minutes.

The hydrolyzed liquid (a) is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, still more preferably 12 parts by mass or more, and 60 parts by mass with respect to 100 parts by mass of the precipitate liquid (b). It is preferably less than or equal to, more preferably 50 parts by mass or less, still more preferably 45 parts by mass or less.

The temperature of the precipitate (b) when the hydrolysis solution (a) is added to the precipitate (b) (that is, the precipitation temperature of the polymethylsilsesquioxane particles) is preferably 10 ° C. or higher, more preferably. Is 15 ° C. or higher, preferably 40 ° C. or lower, and more preferably 35 ° C. or lower.

In the mixed liquid (c) obtained by mixing the hydrolyzed liquid (a) and the precipitate liquid (b), the molar ratio of silicon atoms contained in the hydrolyzate of the monomer of the formula (2) (water / Si). Is preferably 20 or more, more preferably 30 or more, further preferably 40 or more, preferably 120 or less, still more preferably 100 or less, still more preferably 90 or less.

The pH of the precipitate (b) during the addition of the hydrolyzed solution (a) and the pH of the mixed solution (c) after the addition of the hydrolyzed solution (a) are preferably 8.0 or more, more preferably. Is 8.5 or more, more preferably 9.0 or more, preferably 13.0 or less, more preferably 12.5 or less, still more preferably 12.0 or less.

Further, from the viewpoint of promoting dehydration and condensation of the hydrolyzate of the monomer of the formula (2), it is preferable to perform aging after adding the entire amount of the hydrolyzed solution (a). The aging temperature is preferably 25 ° C. or higher, more preferably 40 ° C. or higher, still more preferably 45 ° C. or higher, preferably 70 ° C. or lower, and even more preferably 65 ° C. or lower.

2.2 Post-treatment By mixing the hydrolyzed liquid (a) and the precipitate liquid (b) as described above (aspect 2), or the components used in the hydrolyzed liquid (a) and the precipitate liquid (b). By preparing a mixed solution containing the components used in (Aspect 1), an aqueous dispersion of polymethylsilsesquioxane particles can be obtained. This aqueous dispersion should be purified using a membrane with a pore size of about 0.001 to 0.01 μm (ultrafiltration membrane, etc.) and a membrane with a pore size of 0.002 μm or less (nanofiltration membrane, reverse osmosis membrane, etc.). Is preferable, and ultrafiltration is preferable from the viewpoint of purification efficiency. According to membrane separation (membrane filtration), fine polymethylsilsesquioxane particles can be separated from the anionic surfactant, acid catalyst, base catalyst, etc. used in the hydrolysis condensation reaction, and the degree of hydrophobicity is appropriate. Can be adjusted to a wide range. The shape of the separation membrane is not particularly limited, and examples thereof include a flat membrane shape, a hollow thread shape, a tubular shape, a spiral shape, and a monolith shape, and a hollow thread shape, a tubular shape, and a monolith shape are preferable.

The aqueous dispersion of polymethylsilsesquioxane particles concentrated by membrane separation is preferably replaced with an organic solvent. By substituting with an organic solvent, the aggregation hardness of the polymethylsilsesquioxane particles after drying can be lowered, and the dispersion adhesion to the surface of the toner powder after being mixed with the toner powder can be enhanced. It is possible to increase the fluidity of.

As organic solvents, aromatic hydrocarbons such as toluene, xylene and ethylbenzene; ketones such as acetone, methylethylketone, methylisobutylketone and cyclohexanone; ethers such as tetrahydrofuran, dioxane, ethylene glycol dimethyl ether and diethylene glycol dimethyl ether; ethyl acetate and butyl acetate, Esters such as propylene glycol monomethyl ether acetate, 3-methoxybutyl acetate; methanol, ethanol, isopropanol, n-butanol, 2-methylpropyl alcohol, 2-methyl-2-propanol, ethylene glycol monomethyl ether, propylene glycol monomethyl ether, etc. Alcohol; nitriles such as acetonitrile, propionitrile, butyronitrile, benzonitrile; chloroform; dimethyl sulfoxide and the like, preferably methanol, ethanol, isopropanol, n-butanol, 2-methylpropyl alcohol, 2-methyl-2-propanol and the like. , A water-soluble organic solvent such as acetone, methyl ethyl ketone, ethyl acetate, dioxane, diethyl ether, tetrahydrofuran, acetonitrile, dimethyl sulfoxide, and more preferably methanol, ethanol, isopropanol and the like. Only one of these solvents may be used, or two or more of these solvents may be used in combination.

By drying the organic solvent dispersion of the polymethylsilsesquioxane particles, the polymethylsilsesquioxane particles can be isolated as a powder. The drying method is preferably spray drying from the viewpoint of reducing the aggregation hardness of the polymethylsilsesquioxane particles, but heat drying (stirring heating drying, static heating drying, etc., preferably in a mixer such as a conical ribbon mixer). It is also possible to stir, heat and dry in. Since the polymethylsilsesquioxane particles are used as an organic solvent dispersion, the bonds between the particles during drying are reduced, so that the aggregation hardness of the polymethylsilsesquioxane particles is excessive even after heating and drying. It does not become too much, and when it is dry-mixed with toner powder, it can be loosened and dispersed.

The polymethylsilsesquioxane particles obtained as described above have a hydrophobic agent (for example, hexamethyldisilazane, dimethyldimethoxysilane, diethyldiethoxysilane, rimethylmethoxysilane, butyl rimethoxysilane, dimethyldiku mouth). It shows a predetermined degree of hydrophobicity even if it is not surface-treated with mouth silane, mouth silane, silicone oil, silicone varnish, etc.).

3. 3. Toner composition (toner)
The polymethylsilsesquioxane particles (powder) can be used as a toner external additive for use by mixing with the toner powder. In particular, since the polymethylsilsesquioxane particles of the present invention have a high degree of hydrophobicity, they can exhibit a further excellent effect of improving fluidity.

The content of the polymethylsilsesquioxane particles in the toner composition (toner) containing the toner powder and the toner additive is based on 100 parts by mass of the toner powder from the viewpoint of suppressing aggregation of the toner powders. It is preferably 0.1 part by mass or more, more preferably 0.2 part by mass or more, and further preferably 0.5 part by mass or more. Further, from the viewpoint of facilitating the preparation of the toner while maintaining the characteristics such as fixability and transferability, it is preferably 5 parts by mass or less, more preferably 3 parts by mass or less, and further preferably 2 parts by mass. It is as follows.

As the toner powder, for example, a binder resin containing a colorant can be used. Examples of the binder resin include polyester resin, styrene-acrylic resin, and polyolefin resin. Examples of the colorant include carbon black, phthalocyanine pigment, azo pigment, azo dye, niglocin dye, extender pigment and the like. The content of these colorants is preferably 1 part by mass to 50 parts by mass, and more preferably 1 part by mass to 40 parts by mass with respect to 100 parts by mass of the binder resin.

The toner powder may contain other toner external additives such as a charge control agent and a mold release agent. Examples of the charge control agent include niglosin dyes, azine dyes, metal complex salts, nitrogen-containing compounds, and the like, and examples of the nitrogen-containing compounds include benzoguanamine resin, melamine resin, and quaternary ammonium salt. The content of the charge control agent is preferably 0 parts by mass to 20 parts by mass, and more preferably 0.1 parts by mass to 10 parts by mass with respect to 100 parts by mass of the binder resin.

The release agent includes small particle size silica having a particle size of about several tens of nm (for example, about 5 to 100 nm), large particle size silica having a maximum particle size of about 300 nm (for example, about 100 to 300 nm), and the like. The content of the release agent is, for example, 0.1 part by mass or more, preferably 0.2 part by mass or more, more preferably 0.5 part by mass or more, and for example, 5 parts by mass with respect to 100 parts by mass of the toner powder. It is not less than parts by mass, preferably 3 parts by mass or less, and more preferably 2 parts by mass or less.

The number average particle size of the toner powder is, for example, 1 μm or more, preferably 3 μm or more, more preferably 5 μm or more, and for example, 25 μm or less, preferably 20 μm or less, more preferably 15 μm or less, and particularly preferably 10 μm or less. be. The number average particle size of the toner powder can be measured by a precision particle size distribution measuring device using the Coulter principle.

The fluidity index of the toner composition is, for example, 95% or less, preferably 80% or less, more preferably 70% or less, and particularly preferably 50% or less. The smaller the liquidity index, the better the liquidity, and the measuring method will be shown in the column of Examples described later. The lower limit of the liquidity index is not particularly limited, but may be, for example, 10%, 20%, or 30%.

Since the toner composition contains polymethylsilsesquioxane particles, the effect on the amount of charge is small and the charge does not increase. The method for measuring the amount of charge is shown in the column of Examples described later. The charge amount of the toner composition is, for example, −50 μC / g or more, preferably −40 μC / g or more, more preferably −35 μC / g or more, and particularly preferably −20 μC / g or more. The charge amount is, for example, 30 μC / g or less, preferably 0 μC / g or less, and may be −5 μC / g or less.

Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited by the following examples as well as the present invention, and appropriate modifications are made to the extent that it can meet the purposes of the preceding and the following. Of course, it is possible to carry out, and all of them are included in the technical scope of the present invention.

The polymethylsilsesquioxane particles obtained in the following examples were evaluated as follows.
1. 1. Arithmetic mean value of primary particle size and its coefficient of variation (CV value)
The obtained polymethylsilsesquioxane particle aqueous dispersion was diluted with ion-exchanged water and measured with a light scattering particle size distribution measuring machine (“NicompMODEL380” manufactured by Particle Sigmaning Systems), and the number average particle diameter (μm) was measured. Is obtained, and this value is taken as the average number of primary particles of the polymethylsilsesquioxane particles. Further, the standard deviation is calculated based on the particle size obtained by the above apparatus, and the coefficient of variation (CV value:%) is obtained from the following equation.
Coefficient of variation (CV value:%) = 100 x (standard deviation / number average particle size)

2. 2. Degree of hydrophobicity Add 50 mL of water to a glass beaker with a capacity of 200 mL with a stirrer on the bottom, and gently place 0.2 g of dry powder of polymethylsilsesquioxane particles on the water surface so that the water surface does not undulate. Gently rotate the stirrer. Then, the tip of the burette is inserted into the water in the beaker, and methanol is gradually introduced into the water from the burette. This introduction is carried out until it can be visually confirmed that all the particles on the water surface have sunk. Then, the degree of hydrophobicity is evaluated by the following formula.
Hydrophobicity (%) = Methanol introduction capacity / (Water capacity + Methanol introduction capacity) x 100

3. 3. Amount of Surfactant The obtained polymethylsilsesquioxane particles are diluted with ion-exchanged water, and a counter derived from the surfactant is used with an inductively coupled plasma emission spectrophotometer (ICP, manufactured by Shimadzu Corporation: "ICPE-9000"). The ion content was measured. The measured value of the counterion component multiplied by the dilution ratio was referred to the calibration curve of the counterion content vs. the surfactant amount prepared in advance, and the surfactant amount of the polymethylsilsesquioxane particles was calculated.

4. Toner fluidity 50 parts of toner with an average particle diameter of 10 μm in which carbon black is dispersed as a colorant in a binder resin made of a styrene-n-butyl acrylate copolymer, and 0.5 polymethylsilsesquioxane particle dry powder. The parts are uniformly mixed at a peripheral speed of 20 m / s (rotation speed of 6,000 rpm) for 90 seconds with a mixer (“Labo Miller LM-PLUS” manufactured by Iwatani Sangyo Co., Ltd.) at room temperature to obtain a toner composition.
Using a powder tester (registered trademark) (PT-E type, manufactured by Hosokawa Micron Co., Ltd.), shake a sieve (plain weave wire mesh, standard JIS Z8801-1) with a mesh size of 150 μm, 100 μm, and 45 μm for 10 seconds under the condition of strength 4.0. After sieving the toner composition, the remaining amount of the toner composition on each sieve is measured, and the fluidity index is calculated using the formula shown below. The smaller the fluidity index, the better the fluidity of the toner composition.
Liquidity index (%) = [(A + 0.6 × B + 0.2 × C) / measured sample weight] × 100
A: Remaining amount of toner composition (g) on a sieve with an opening of 150 μm
B: Remaining amount of toner composition (g) on a sieve having an opening of 100 μm.
C: Remaining amount of toner composition (g) on a sieve having an opening of 45 μm

5. Toner chargeability In an environment of temperature 23 ° C. and humidity 50%, 0.25 g of the toner composition obtained in the above "4. Toner fluidity" test and 4.75 g of a ferrite carrier (F96-150, manufactured by Powdertech). After carefully evaluating each of these, put them in a polyethylene container with a capacity of 20 mL, mix them at a rotation speed of 70 rpm for 30 minutes, and then set them in a blow-off type charge measuring instrument (TB-200, manufactured by Kyocera Chemical Co., Ltd.), and blow pressure 0. Flow with nitrogen gas for 20 seconds under the condition of 1 MPa · s and measure the charge. The charge amount (μC / g) is calculated by dividing the measured charge by the mass of the flying toner.

Example 1
To a glass reaction vessel equipped with a stirrer, a thermometer, a dropping port and a cooler, 94.2 parts by mass of deionized water and 0.21 parts by mass of a 10% acetic acid aqueous solution were added, and methyltrimethoxysilane was stirred at room temperature. 100.6 parts by mass (hereinafter referred to as "MTMS") was added from the dropping port to hydrolyze MTMS. 50 minutes after the completion of MTMS dropping, add 9.54 parts by mass of a 20% aqueous solution of polyoxyethylene alkyl ether sulfate ester salt (Neucol 1305-SN, manufactured by Nippon Emulsifying Co., Ltd.) as an aqueous solution of anionic surfactant to add a hydrolyzed solution. Obtained.

On the other hand, 686.6 parts by mass of deionized water and 3.18 parts by mass of 25% ammonia water were added to a glass reaction kettle equipped with a stirrer, thermometer, dropping port and cooler different from the above reaction kettle at room temperature. After stirring with, add 10.32 parts by mass of a 20% aqueous solution of polyoxyethylene alkyl ether sulfate ester salt (Neucol 1305-SN, manufactured by Nippon Emulsifier Co., Ltd.) as an aqueous solution of the anionic surfactant, and further make it uniform at room temperature. The mixture was stirred so as to be a precipitate.
Next, while stirring the precipitate at room temperature, the hydrolyzate was added dropwise to the precipitate over 60 minutes from the dropping port, and polymethylsilsesquioxane particles were precipitated, and the entire amount of the hydrolyzate was further added dropwise. After that, the reaction solution was heated to 60 ° C. and aged at 60 ° C. for 1 hour, and then the reaction solution was cooled and filtered with a 300 mesh to evaluate the dispersion stability and the polymethylsilsesquioxane particles. Obtained an aqueous dispersion in which The number average particle size of the obtained polymethylsilsesquioxane particles was 0.018 μm, and the coefficient of variation was 22.6%.

This polymethylsilsesquioxane particle dispersion was concentrated with an ultrafiltration module (Microza UF manufactured by Asahi Kasei Chemicals Co., Ltd.) and replaced with a methanol solvent to obtain a polymethylsilsesquioxane particle methanol dispersion having a concentration of 10%. Obtained. Further, 0.1 part by mass of tetrabutylammonium bromide (1% by mass with respect to the polymethylsilsesquioxane particles) was added and dissolved in 100 parts by mass of the obtained polymethylsilsesquioxane particle methanol dispersion. .. Then, it was dried by heating at 40 ° C. for 2 hours, and pulverized with a lab miller (LM-PLUS) for 90 seconds to obtain a dry powder (1) of polymethylsilsesquioxane particles. Table 1 shows the degree of hydrophobicity of the obtained powder. Table 1 shows the fluidity and chargeability of the toner composition prepared by using the obtained powder.

Example 2
A dry powder (2) of polymethylsilsesquioxane particles was obtained in the same manner as in Example 1 except that tetrabutylammonium bromide was not added. Table 1 shows the degree of hydrophobicity of the obtained powder. Table 1 shows the fluidity and chargeability of the toner composition prepared by using the obtained powder.

Example 3
A polymethylsilsesquioxane particle methanol dispersion was obtained in the same manner as in Example 1. The obtained dispersion was spray-dried with a spray dryer equipped with a four-fluid nozzle (internal inlet temperature 150 ° C., outlet temperature 70 ° C.) without adding tetrabutylammonium bromide, and polymethylsilsesquioxane particles were obtained. The dry powder (3) of the above was obtained. Table 1 shows the degree of hydrophobicity of the obtained powder. Table 1 shows the fluidity and chargeability of the toner composition prepared by using the obtained powder.

Comparative Example 1
In the same manner as in Example 1, an aqueous dispersion of polymethylsilsesquioxane particles was obtained.
Unlike Example 1, concentration by ultrafiltration and substitution with methanol solvent were not performed, and the obtained polymethylsilsesquioxane particle aqueous dispersion was used as it was in a spray dryer equipped with a four-fluid nozzle (internal inlet temperature 150 ° C., It was spray-dried at an outlet temperature of 70 ° C.) to obtain a dry powder (4) of polymethylsilsesquioxane particles. Table 1 shows the degree of hydrophobicity of the obtained powder. Table 1 shows the fluidity and chargeability of the toner composition prepared by using the obtained powder.

Claims (6)

Polymethylsilsesquioxane particles having a degree of hydrophobicity of 15% or more and 50% or less , and an average number of primary particle diameters of 0.001 μm or more and 0.10 μm or less. The polymethylsilsesquioxane particles according to claim 1, which contain a quaternary ammonium salt. A toner external preparation composed of the polymethylsilsesquioxane particles according to claim 1 or 2. An aqueous dispersion of polymethylsilsesquioxane particles is obtained by hydrolyzing and condensing a trifunctional organic silicon monomer represented by the formula (2) in the presence of water, a base catalyst, and an anionic surfactant. Prepare and
A method for producing polymethylsilsesquioxane particles, in which the aqueous dispersion is membrane-separated and then dried.
CH ₃ Si (OR ² ) ₃ ... (2)
[In the formula (2), R ² represents an alkyl group having 1 to 6 carbon atoms, and a plurality of R ² may be different from each other. ] The method for producing polymethylsilsesquioxane particles according to claim 4, wherein the aqueous dispersion of the polymethylsilsesquioxane particles is membrane-separated, further replaced with an organic solvent, and then dried. The method for producing polymethylsilsesquioxane particles according to claim 4 or 5, wherein the content of the anionic surfactant in the dried polymethylsilsesquioxane particles is 1.0% by mass or less.