JP3305734B2 - Method for producing polymer particles - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a narrow particle size distribution, relates to a method for producing a broad polymer particle child molecular weight distribution.

[0002]

2. Description of the Related Art As a means for developing an electrostatic latent image formed on an electrophotographic photoreceptor or an electrostatic recording medium, a method using a liquid developer (wet development method) and a method using a binder resin are used. dye,
A system using a toner in which a colorant such as a pigment and, if necessary, a charge controlling agent or the like is dispersed, or a one-component or two-component dry developer in which the toner is mixed with a solid carrier (dry development method) And are generally adopted. Each of these methods has advantages and disadvantages, but at present, dry development is often used.

In order to provide high image quality and high durability, the toner must have a small particle size and a narrow particle size distribution.
That the surface shape is smooth and the charge control agent is
It is required that they are uniformly dispersed. That is, grain
Diameter affects resolution, sharpness, halftone reproducibility, etc.
If the particle size distribution width is wide, a specific particle size selection phenomenon occurs,
The durability is impaired. Surface shape is not smooth
In the case, due to the stress during stirring of the developing
Crushing produces ultrafine powder, which forms a two-component developer.
Causes fusion to the carrier and deterioration of the charge.
In the case of component-type developers, fusion to toner thin film members
Cause white streaks. In addition, the charge control agent toner
The non-uniform dispersion in the soil causes soiling .

[0004] A conventional toner is produced by a general production method, that is, a method in which a resin, a dye / pigment, and a charge controlling agent are melt-kneaded, and pulverized and classified by a mechanical or air collision type pulverizer. In the toner, particularly when it is intended to obtain a particle having a small particle size and a narrow particle size distribution, the production capacity and the yield are remarkably reduced and the cost is increased. Of the toner charge characteristics due to uneven dispersion of the toner. In addition, the surface shape of the particles obtained by the pulverization has considerably many projections, and fusion to the carrier or the member for thinning the toner is likely to occur. Further, there is a disadvantage that an expensive charge control agent or the like which originally exhibits a function on the toner surface is also contained in the toner, resulting in a high cost.

[0005] Therefore, many proposals have been made regarding a toner that provides high image quality and high durability and a method for manufacturing the same. For example, core particles containing a color pigment and a charge control agent therein are formed by a suspension polymerization method (Japanese Patent Publication No. 51 (1988)).
No. -14895 and Japanese Patent Publication No. 47-51830), however, this method is difficult to remove the dispersion stabilizer, surfactant and the like adhering to the surface, and is liable to cause charge deterioration. In polymerization, small and narrow particle size distribution (10
μm or less) is difficult to stably produce.

Further, core particles containing a pigment and a charge controlling agent therein are formed by a spray granulation method (Japanese Patent Publication No. Sho.
7-494, and JP-B-56-13945), but this method is very difficult to control the particle size.
It has disadvantages such as the necessity of classification after granulation or the inability to use a polymer resin effective for preventing hot offset.

On the other hand, as a method for easily obtaining a toner having a small particle size and a narrow particle size distribution, Japanese Patent Application Laid-Open No.
4. Japanese Patent Application Laid-Open No. 61-275766 discloses a method in which polymer particles having a narrow particle size distribution are synthesized by a seed emulsion polymerization method, and a coloring substance, a toner property-imparting substance, a protective layer, or the like is adhered to the surface. Attempts have been made to produce so-called core-shell structured toners, but the electrical properties and durability were poor due to uneven distribution of colored substances and the like on the toner surface.

On the other hand, attempts have been made to synthesize similar polymer particles having a narrow particle size distribution by a dispersion polymerization method to form a toner. JP-A-61-18965, JP-A-61-1986
No. 228458 discloses an attempt to color particles obtained by dispersion polymerization and use them as toner. However, they did not have a cross-linking component having good hot offset properties and a wide molecular weight distribution.

The particles obtained by dispersion polymerization as disclosed by the present inventors in JP-A-61-19602 are further screened.
A method of absorbing a crosslinkable monomer by applying to a emulsion polymerization system was found in JP-A-64-26617, but a large number of steps such as shifting the dispersion polymerization system to a seed emulsion polymerization system and performing swelling were carried out. Was needed.

However, the present inventors have disclosed in Japanese Patent Application Laid-Open No. 63-294.
02 showed the possibility of modifying and growing the particles by adding a vinyl monomer while maintaining the dispersion polymerization system, but it was difficult to introduce a crosslinking component into the particles.

An object of the present invention is to provide a method for producing particles size distribution narrow and broad molecular weight distribution polymer particles child, also a fixing of the hot offset resistance is suppressed, digital latent Line reproducibility, halftone reproducibility,
An object of the present invention is to provide a toner that forms a high-quality image with excellent halftone reproducibility.

Another object of the present invention is to provide image forming particles which have a small variation in environment and a sharp distribution of the charge amount without fluctuation in the particle diameter during running.

[0013]

Means for Solving the Problems The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, have reached the present invention. That is, the present invention is dissolved in vinyl-monomers, or polymers produced swells in most undissolved hydrophilic organic liquid, dissolved in the hydrophilic organic liquid vinyl monomer and a crosslinking agent When the polymerization is carried out using a polymer dispersion stabilizer, the crosslinker for the vinyl monomer is performed at 3% by weight or less until the conversion rate reaches 10%, and then the crosslinker at 10% by weight or less is batch-divided or divided or continuously. A method for producing polymer particles by adding and polymerizing in an initial stage, or during polymerization,
Or a preparation how the polymer particles, characterized by adding a coloring agent after completion of polymerization.

In the present invention, a narrow particle size distribution means a coater multisizer (manufactured by Coulter Electronics Co., Ltd.).
In the case of using an aperture tube of 100 μm, the setting of the aperture current and the like is performed by setting the ratio of the volume average particle diameter (dv) to the number average particle diameter (dn) when automatically measuring (30,000 or more count values). 1.00
It means a particle size distribution in the range of ≦ (dv / dn) ≦ 1.20. As a particle size distribution after completion of the polymerization, dv / dn is 1.1.
5 or less is desirable. In the case of the polymer particles used for the electrophotographic toner, the glass transition point is 40 to 90 ° C., the weight average molecular weight is 0.5 to 100,000, and the high molecular weight component or the crosslinking component of 1,000,000 or more is 5 to 50 in weight. % Is preferable from the viewpoint of securing the fixing property by the heat roller and the anti-offset property.

The amount of the crosslinking component is determined by extracting the particles on the filter by heating and refluxing in a solvent that dissolves the polymer component, or by dissolving, filtering or centrifuging the particles in the solvent using a filter aid. It can be performed using an operation such as sedimentation.

The resin particles are added with a polymer dispersant which dissolves in the hydrophilic organic liquid to the hydrophilic organic liquid, and the polymer which dissolves in the hydrophilic organic liquid but forms a polymer is formed by the hydrophilic organic liquid. It is produced by adding one or more vinyl monomers which swell or hardly dissolve and polymerize. A reaction in which a polymer smaller than the target particle diameter but narrow in particle size distribution is used as seed particles in advance and grown in the above-described system is also included. The monomer used for the growth reaction may be the same monomer as that used to produce the seed particles or another monomer, but the polymer must not be dissolved in the hydrophilic organic liquid.

It is important that the crosslinking component is introduced in an amount of 3% by weight or less based on the monomer from the start of the polymerization until the conversion of the monomer reaches 10%. The use of causes agglomeration of the system. However, when a further crosslinking component is required, it is possible to add an amount of 10% by weight or less of the monomer remaining in the system at a stage where the conversion of the vinyl monomer is 10% or more. Of course, in the case of the above-described reaction of growing using a polymer having a smaller particle size than the target particle size but having a narrow particle size distribution, a crosslinking agent of 10% by weight or less of the added monomer can be used.

In the present invention, the hydrophilic organic liquid used as a diluent for the monomer used during the formation of the particles and during the growth reaction of the particles includes, for example, methyl alcohol, ethyl alcohol, denatured ethyl alcohol, isopropyl alcohol, n-butyl alcohol. , Isobutyl alcohol, t
tert-butyl alcohol, sec-butyl alcohol, tert-amyl alcohol, 3-pentanol,
Alcohols such as octyl alcohol, benzyl alcohol, cyclohexanol, furfuryl alcohol, tetrahydrofurfuryl alcohol, ethylene glycol, glycerin, diethylene glycol, methyl cellosolve, cellosolve, isopropyl cellosolve, butyl cellosolve, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, Examples include ether alcohols such as diethylene glycol monomethyl ether and diethylene glycol monoethyl ether.

As these organic liquids, one kind or a mixture of two or more kinds can be used. In addition, alcohols,
By using together with the above-mentioned alcohols and ether alcohols in an organic liquid other than and ether alcohols,
Changes the various SP values under conditions that do not impart solubility to the polymer particles produced in the organic liquid, changes the polymerization conditions, suppresses the size of the generated particles, the coalescence of the particles, and the generation of new particles It is possible to As the organic liquid used in combination, hexane, octane, petroleum ether, cyclohexane, benzene, toluene, hydrocarbons such as xylene, carbon tetrachloride, trichloroethylene, halogenated hydrocarbons such as tetrabromoethane ethyl ether, dimethyl glycol, Trioxane, ethers such as tetrahydrofuran, methylal, acetal such as diethyl acetal, acetone, methyl ethyl ketone, methyl isobutyl ketone, ketones such as cyclohexane, butyl formate, butyl acetate, ethyl propionate, esters such as cellosolve acetate, formic acid, Acids such as acetic acid and propionic acid, sulfur and nitrogen containing nitropropene, nitrobenzene, dimethylamine, monoethanolamine, pyridine, dimethylsulfoxide and dimethylformamide Machine compounds, other water is also included.

The above-mentioned solvents mainly composed of a hydrophilic organic liquid include SO ₄ ² ~, NO ₂ ~, PO ₄ ³ ~, Cl ~, Na ⁺ , K ⁺ , Mg
^The polymerization may be carried out in the presence of ²⁺ , Ca ²⁺ and other inorganic ions.

For example, when a solvent or a mixed solvent having a relatively high Sp value from the vinyl monomer or a mixed solvent having a relatively high polarity is used in the initial stage of polymerization, that is, in the stage of generating core particles, the precipitated core particles become small particles, and other solvents are later used. The addition promotes coalescence of the particles and can adjust the particle size and the particle size distribution.

The average particle size, particle size distribution, drying conditions, etc. of the polymer particles produced can be adjusted by changing the type and composition of the mixed solvent at the start of polymerization, during the polymerization, and at the end of polymerization, respectively.

Examples of the dispersion stabilizer for producing seed particles or growing particles include acrylic acid, methacrylic acid, α
An acid such as cyanoacrylic acid, α-cyanomethacrylic acid, itaconic acid, crotonic acid, fumaric acid, maleic acid or maleic anhydride, or an acrylic monomer containing a hydroxyl group, for example, β-hydroxyethyl acrylate Β-hydroxyethyl methacrylate, β-hydroxypropyl acrylate, β-hydroxypropyl methacrylate, γ-hydroxypropyl acrylate, γ-hydroxypropyl methacrylate, 3-chloro-2-acrylate
Hydroxypropyl, 3-chloro-2-hydroxypropyl methacrylate, diethylene glycol monoacrylate, diethylene glycol monomethacrylate, glycerin monomethacrylate, N-methylol acrylamide, N-methylol methacrylamide, etc., with vinyl alcohol or vinyl alcohol Ethers such as vinyl methyl ether, vinyl ethyl ether, vinyl propyl ether or the like, or esters of vinyl alcohol and a compound having a carboxyl group,
For example, vinyl acetate, vinyl propionate, vinyl butyrate, etc., acrylamide, methacrylamide, diacetone acrylamide or their methylol compounds or sulfonated acrylamides, acrylic chloride, acid chlorides such as methacrylic chloride, vinylpyridine, vinylpyrrolidone, Homopolymers or copolymers such as those having a nitrogen atom such as vinylimidazole and ethyleneimine or a heterocycle thereof, polyoxyethylene,
Polyoxypropylene, polyoxyethylene alkylamine, polyoxypropylene alkylamine, polyoxyethylene alkylamide, polyoxypropylene alkylamide, polyoxyethylene nonylphenyl ether, polyoxyethylene laurylphenyl ether, polyoxyethylene stearyl Phenyl esters, polyoxyethylenes such as polyoxyethylene nonylphenyl ester, celluloses such as methyl cellulose, hydroxyethyl cellulose, hydroxypropyl cellulose, or the above-mentioned hydrophilic monomers and styrene, α-methyl Copolymer with styrene, vinyltoluene, etc. having a benzene nucleus or derivatives thereof or acrylic acid or methacrylic acid derivatives such as acrylonitrile, methacrylonitrile, acrylamide Body, further, the crosslinking monomer such as ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, allyl methacrylate, a copolymer such as divinylbenzene can be used.

These polymeric compound dispersants may be appropriately selected depending on the hydrophilic organic liquid to be used, the seed of the target polymer particles, and whether the seed particles or the grown particles are to be produced.
In particular, in order to mainly prevent steric coalescence of the polymer particles, those having high affinity to the polymer particles and high adsorptivity, and high affinity and solubility to the hydrophilic organic liquid are selected. Further, in order to increase the repulsion of the particles three-dimensionally, those having a certain length of the molecular chain, preferably those having a molecular weight of 10,000 or more are selected. However, if the molecular weight is too high, the viscosity of the solution will increase significantly, and the operability and agitation will be poor, and the resulting polymer will have a variation in the probability of precipitation on the particle surface, so care must be taken.

It is also effective to stabilize the particles by allowing the monomers of the above-mentioned polymer compound dispersants to coexist with the monomers constituting the intended polymer particles.

In combination with these polymer compound dispersants, metals such as cobalt, iron, nickel, aluminum, copper, tin, lead and magnesium or alloys thereof (particularly 1 μm) are used.
The following is preferable) iron oxide, copper oxide, nickel oxide,
Inorganic compound fine powders of oxides such as zinc oxide, titanium oxide and silicon oxide, higher alcohol sulfates, alkylbenzene sulfonates, α-olefin sulfonates,
Anionic surfactants such as phosphate esters, alkylamine salts, amino alcohol fatty acid derivatives, polyamine fatty acid derivatives, amine salt types such as imidazoline, alkyl trimethyl ammonium salts, dialkyl dimethyl ammonium salts, alkyl dimethyl benzyl ammonium salts, Nonionic surfactants such as quaternary ammonium salt-type cationic surfactants such as viridium salts, alkylisoquinolinium salts, and benzethonium chloride, and fatty acid amide derivatives and polyvalent alcohol derivatives such as alanine-type (for example, dodecyldiamine) Even when amino acid-type or betaine-type amphoteric surfactants such as (aminoethyl) glycine and di (octylaminoethyl) glycine) are used in combination, the resulting polymer particles can be further stabilized and the particle size distribution can be further improved. it can.

In general, the amount of the polymer dispersant used depends on the type of the polymerizable monomer for forming the desired polymer particles, but it is 0.1% by weight to 10% by weight based on the hydrophilic organic liquid.
More preferably, it is 1% by weight to 5% by weight. When the concentration of the polymer dispersion stabilizer is low, the resulting polymer particles have a relatively large diameter, and when the concentration is high, small particles are obtained. The effect on reducing the diameter is small.

The above-mentioned polymer dispersion stabilizer and, if necessary, inorganic fine powder, pigment and surfactant are necessary for producing seed particles. The polymerization may be carried out in the presence of a vinyl monomer solution or a seed particle dispersion added for the purpose of preventing coalescence of the two.

The initially formed particles are stabilized by a polymer dispersion stabilizer distributed in the hydrophilic organic liquid and on the surface of the polymer particles while maintaining an equilibrium. If present considerably, it will swell somewhat and become sticky and will agglomerate over the steric repulsion of the polymeric dispersion stabilizer.

Further, when the amount of the monomer is extremely large relative to the hydrophilic organic liquid, the produced polymer is completely dissolved, and does not precipitate unless polymerization proceeds to some extent. The state of precipitation in this case takes the form of forming a highly sticky mass.

Therefore, the amount of the monomer relative to the hydrophilic organic liquid at the time of producing the particles is naturally limited, and varies somewhat depending on the type of the hydrophilic organic liquid, but is about 100% by weight or less, preferably 50% by weight. % Or less is appropriate.

In the present invention, the vinyl monomer is a compound which can be dissolved in a hydrophilic organic liquid, for example, styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, α-methylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, p-n-butylstyrene, p-tert-butyltostyrene, p-n-hexylstyrene, p-n-octylstyrene, p-n-nonylstyrene, p- Styrenes such as n-decylstyrene, p-n-dodecylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, 3,4-dichlorostyrene, methyl acrylate, ethyl acrylate, n-acrylate -Butyl, isobutyl acrylate, propyl acrylate, n-octyl acrylate, dodecyl acrylate, acrylic Lauryl, 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl, phenyl acrylate, alpha-chloromethyl acrylate, methyl methacrylate, ethyl methacrylate,
Propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, lauryl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, dimethylaminoethyl methacrylate, methacrylic acid Α-methyl fatty acid monocarboxylic acid esters such as diethylaminoethyl, acrylic acid or methacrylic acid derivatives such as acrylonitrile, methacrylonitrile, and acrylamide; vinyl halides such as vinyl chloride, vinylidene chloride, vinyl bromide, and vinyl fluoride; Or a mixture thereof with each other and a mixture thereof with a monomer containing 50% by weight or more thereof and copolymerizable therewith.

Further, by copolymerizing a small amount of a monomer having a relatively high polarity, it is possible to control the polymerization stability of the particles and the triboelectric charging property when the particles are powdered. Examples of such anionic polymerizable monomers include carboxyl group-containing monomers: for example, acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid, fumaric acid, monobutyl itaconate, and monobutyl maleate.

Phosphoric acid group-containing monomers: For example, acid phosphooxyethyl methacrylate, acid phosphooxypropyl methacrylate, 3-chloro-2-acid phosphooxypropyl methacrylate and the like.

Sulfonic acid group-containing monomers: Examples thereof include 2-acrylamide, 2-methylpropanesulfonic acid, 2-sulfoethyl methacrylate, and styrenesulfonic acid.

The cationic polymerizable monomers include:
Nitrogen-containing alkyl acrylate or methacrylate:
For example, dimethylaminoethyl acrylate, diethylaminoethyl methacrylate or a quaternary salt thereof can be mentioned.

In order to introduce the crosslinking component into the polymer particles, a so-called crosslinking agent having two or more polymerizable double bonds is used. The amount of the cross-linking agent based on the monomer is preferably 3% by weight or less, and more preferably 1.5% by weight or less, from the start of the polymerization until the polymerization conversion rate reaches 10%.
If the conversion is 10% or more, if necessary, 10% by weight or less of a cross-linking agent may be added to the remaining vinyl monomer in a lump, dividedly or continuously. It is more preferable to continuously or separately add a metering pump or the like in accordance with the progress of the polymerization, or to mix and add the hydrophilic organic liquid or the vinyl monomer if the growth reaction is performed. .

The concentration of the cross-linking agent must be suppressed at the initial stage of polymerization because the cross-linking agent is present at a certain concentration or more at the time of the initial stabilization of the adsorption of the dispersion stabilizer, and the cross-linking structure between the core particles is formed. It is because the stability is extremely impaired, and once the core particles are stabilized, the subsequent growth reaction of the particles, that is, the process from the swelling of the core particles by the monomer to the polymerization is almost impossible. Done.

Preferred examples of the crosslinking agent include divinylbenzene, divinylnaphthalene and aromatic divinyl compounds which are derivatives thereof, ethylene glycol diacrylate, ethylene glycol dimethacrylate, triethylene glycol dimethacrylate, tetraethylene glycol dimethacrylate, , 3-butylene glycol dimethacrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, 1,4-butanediol diacrylate,
Neopentyl glycol diacrylate, 1,6-hexanediol diacrylate, pentaerythritol diacrylate, pentaerythritol triacrylate, pentaerythritol tetraacrylate, pentaerythritol dimethacrylate, pentaerythritol trimethacrylate, pentaerythritol tetramethacrylate, glycerol dimethacrylate, glycerol Diethylene carboxylate such as diacrylate, glycerol acroxydimethacrylate, 1,1,1-trishydroxymethylethane diacrylate, N, N-divinylaniline, divinyl ether, divinyl sulfide, all vinylidene compounds such as divinyl sulfone and Compounds with three or more vinyl groups used alone or in mixtures It is.

When the growth polymerization reaction is subsequently performed using the thus crosslinked particles, the inside of the resulting polymer particles becomes crosslinked. On the other hand, when the above-mentioned crosslinking agent is contained in the vinyl monomer solution used for the growth reaction, a polymer having a cured particle surface is obtained.

In the polymerization system of the present invention, the average molecular weight can be adjusted by using a so-called chain transfer agent having a large chain transfer constant.

For example, halogenated hydrocarbons such as carbon tetrachloride, carbon tetrabromide, ethyl dibromide acetate, ethyl tribromide acetate, ethyl dibromide, ethane dibromide, ethane dichloride, diazothioether, benzene And tert-dodecyl mercaptan; mercaptans such as n-dodecyl mercaptan; and disulfides such as diisopropylzantogen disulfide.

Those usually used as polymerization initiators for the monomers include, for example, azo-based polymerization initiators such as 2,2'-azobisisobutyronitrile and 2,2'-azobis (2,4-dimethylvaleronitrile). Initiators, peroxide polymerization initiators such as lauryl peroxide, benzoyl peroxide, tert-butyl peroctoate, etc .; persulfide initiators such as potassium persulfate; and sodium thiosulfate, amine and the like. A system used in combination is used.

The concentration of the polymerization initiator is preferably 0.1 to 10 parts by weight based on 100 parts by weight of the vinyl monomer.

The concentration of the polymer dispersant and the vinyl monomer in the hydrophilic organic liquid and the compounding ratio are determined in accordance with the polymerization conditions of the seed particles in accordance with the target, average particle size, and target particle size distribution of the polymer particles. You.

Generally, if the average particle diameter of the seed particles is to be reduced, the concentration of the polymer dispersant is set high, and if the average particle diameter is increased, the concentration of the polymer dispersant is set low. .

On the other hand, if the particle size distribution is to be made very sharp, the vinyl monomer concentration is set low, and if a relatively wide distribution is acceptable, the vinyl monomer concentration is set high.

For the production of the particles, a polymer dispersion stabilizer is completely dissolved in a hydrophilic organic liquid, and then one or more kinds of vinyl monomers, a polymerization initiator and, if necessary, an inorganic fine powder,
Add surfactant, dye, pigment, etc., 30 ~ 300rpm
Decomposition of the initiator used while stirring at a speed as low as possible with normal stirring of m, and at a speed such that the flow in the tank becomes uniform using a turbine type stirring blade rather than a paddle type. The polymerization is carried out by heating at a temperature corresponding to the speed.
In addition, since the temperature at the initial stage of polymerization has a great influence on the particle size to be produced, it is preferable to raise the temperature to the polymerization temperature after adding the monomer, and to dissolve the initiator in a small amount of solvent before adding.

At the time of polymerization, it is necessary to sufficiently purge oxygen in the air in the reaction vessel with an inert gas such as nitrogen gas or argon gas. If the oxygen purge is insufficient, fine particles are likely to be generated.

In order to carry out the polymerization in the high polymerization rate region, a polymerization time of 5 to 40 hours is required. However, the polymerization is stopped at a desired particle size and particle size distribution, and a polymerization initiator is added sequentially. The polymerization rate can be increased by performing the reaction under high pressure.

After completion of the polymerization, unnecessary fine particles, residual monomers, polymer dispersion stabilizers, and the like are removed by operations such as sedimentation, centrifugation, and decantation, and then collected as a polymer slurry. -It can be dried and powdered by a fluidized bed dryer or the like.

When the polymer particles thus obtained are used as an electrophotographic toner, they need to be colored. Coloring includes a method of applying and coating a colorant on the surface and a method of coloring the inside, but considering the color characteristics as a toner and the electrical characteristics for electrophotography, it is more preferable that the inside is colored. .

As a method of uniformly coloring the particles from the surface to the inside, a dye, a reactive dye,
Pigments, lipophilic pigments, etc. can be added to incorporate toner colorants into the particles. However, considering the stability of polymerization, it is more likely that the colorant will diffuse into the particles after polymerization is complete. preferable. For example, a state in which a dye is added to a dispersion liquid after polymerization is completed or a slurry from which residual monomers, a dispersion stabilizer, and the like are removed, and the obtained polymer particles are heated to Tg or more, or are slightly swollen with a dispersion medium. Can be used to dye the particles. When the dye is dyed in an organic solvent, the resin particles used do not dissolve or slightly swell, specifically, the solubility parameter [SP
And the difference between the [SP value] of the resin particles to be used is 1.0 or more, preferably 2.0 or more. For example, for a styrene-acrylic resin, [SP value]
Of alcohols such as methanol, ethanol, n-propanol or the like, or n-hexane, n-heptane or the like having a low [SP value]. Of course, if the difference in the [SP value] is large, the wetting to the resin particles becomes worse, and a good dispersion of the resin particles cannot be obtained.
The difference is preferably 2-5.

The dye used for dyeing has a ratio [D1] / [D2] of the solubility [D1] in the organic solvent used and the solubility [D2] in the organic solvent capable of dissolving the resin of 0.5.
Any dye may be used as long as it is below, but in order to maintain a high powder resistance of the toner after dyeing, as a disperse dye, an oil-soluble dye and a method of dyeing, an organic solvent is used. The dye is dispersed and dissolved, and then the resin particles are dispersed.
The weight ratio of the dye to the resin particles may be determined according to the degree of coloring, but usually 1 to 50 parts by weight per 100 parts by weight of the resin particles. After dispersing the dye and the resin particles in the organic solvent, it is desirable to keep the liquid temperature at or below the glass transition temperature of the resin particles and at or above 20 ° C. lower than the glass transition temperature, and to stir for about 30 minutes to 1 hour. . The method of stirring is a commercially available stirrer, such as a homomixer,
What is necessary is just to stir using a magnetic stirrer etc.

Further, a dye is directly added to a slurry obtained at the end of polymerization by dispersion polymerization or the like, that is, a solution in which polymer resin particles are dispersed in an organic solvent, and the mixture is heated and stirred under the above conditions. good.

The particles are stabilized by a dispersion stabilizer. Even if the dyeing temperature is raised to a temperature higher than the glass transition temperature of the resin, the particles do not agglomerate or fuse with each other. The rate of being taken in) increases.

As the dye used for dyeing, the ratio [D1] / [D2] of the solubility [D1] in a solvent used in dyeing and the solubility [D2] in an organic solvent capable of dissolving the resin particles is used.
Is required to be 0.5 or less, but [D1] / [D
2] is particularly preferably 0.2 or less. As for the solubility [D2] in an organic solvent capable of dissolving the resin particles, it is desirable to determine the solvent [D2] by experimentally or by determining the solvent that best dissolves the resin particles from the SP value.
The high solubility of the dye in a solvent that dissolves the resin well (preferably having an SP value of the resin ± 2) means that the affinity between the resin and the dye is high.
When [D1] / [D2] is 0.5 or more, no dyeing occurs or coloring is insufficient. No particular limitation is imposed on the dye as long as it satisfies the above-mentioned solubility characteristics.However, water-soluble dyes such as cationic dyes and anionic dyes may have large environmental fluctuations, and also have low toner resistance and low transfer rate. There is a risk of deterioration. Accordingly, vat dyes, disperse dyes, and oil-soluble dyes are preferred, and oil-soluble dyes are particularly preferred.

Further, several kinds of dyes can be used in combination depending on the coloring. The ratio (weight) between the dye to be dyed and the resin particles is arbitrarily selected according to the degree of coloring, but usually 1 to 50 parts by weight of the dye is preferred per 100 parts by weight of the resin particles.

The dye in the present invention can be appropriately selected depending on the resin particles and the solvent used for dyeing.
For example, when an alcohol such as methanol or ethanol having a high SP value is used as a dyeing solvent and a styrene-acrylic resin having an SP value of about 9 is used, the resin does not dissolve in the dyeing solvent. However, it is well dissolved in organic solvents such as acetone, toluene and benzene having an SP value of about 9.

In this case, examples of the dye that can be used include CI SOLVENT YELLOW (6, 9, 17, 31, 35, 100, 102, 1).
03, 105) CI SOLVENT Orange (2, 7, 13, 14,66) CI SOLVENT RED (5, 16, 17, 18, 19, 22, 23, 14
3, 145, 146, 149,150, 151, 157, 158) CI SOLVENT Violet (31, 32, 33, 37) CI SOLVENT BLUE (22, 63, 78, 83-86, 191, 19)
4, 195, 104) CI SOLVENT Green (24, 25) CI SOLVENT Brown (3, 9) and the like are preferable. Commercially available dyes include, for example, Aizen SOT dye Yellow-1,
3, 4, Orange-1, 2, 3, Scarlet-1, Red-1, 2, 3, Bro
wn-2, Blue-1, 2, Violet-1, Green-1, 2, 3, Black-
1,4,6,8 and BASF sudan dye Yellow-146,150, Orange
-220, Red-290, 380, 460, Blue-670 and Mitsubishi Kasei's Diaresin Yellow-3G, F, H2G, HG, HC,
HL, Orange-HS, G, Red-GG, S, HS, A, K, H5B, Viole
tD, Blue-J, G, N, K, P, H3G, 4G, Green-C, Brown
A and Orient Chemical's oil color Yellow-3G, GG-S,
# 105, Orange-PS, PR, # 201, Scarlet- # 308, R
ed-5B, Brown-GR, # 416, Green-BG, # 502, Blue-BO
S, IIN, Black-HBB, # 803, EB, EX Sumitomo Chemical Sumiplast Blue GP, OR, Red
FB, 3B, Yellow FL7G, GC, Nippon Kayaku Kayaron
Polyester black EX-SF300, Kaya set Red B
, Blue A-2R etc. can be used.

Of course, the dye is not limited to the above examples since it is appropriately selected by the combination of the resin particles and the solvent used for dyeing.

After completion of the dyeing step, it is necessary to remove the dispersion stabilizer, residual monomers, ultrafine particles and undyed dye. Filtration by a filter, centrifugal sedimentation, separation by a liquid cyclone or the like may be performed. The dispersion stabilizer is substantially removed by this treatment and has little effect on triboelectric charging.

If the obtained product is in the form of a wet cake, it is dried with a rotary kiln or a vibrating fluidized drier, and if it is in the form of a slurry, a spray drier or a fluidized bed drier can be used.

By mixing a charge controlling agent, a release improver, and a flow improver with the slurry or cake during drying,
It can be uniformly attached to the particle surface.

The dry dyeing resin particles obtained as described above may then be mechanically driven with a charge controlling agent on the surface thereof.

As a driving method, the colored resin particles and the charge control agent are mixed in advance, and then mechanical energy is applied. The mixing method may be any method such as a ball mill, a V blender, and Henschel. Examples of the method of applying mechanical energy include a method of applying an impact force to the mixture by a blade rotating at a high speed, a method of charging the mixture into a high-speed air stream to accelerate the particles, and causing the particles to collide with each other or a suitable collision plate. There is. Specific devices include Mechanofusion (Hosokawa Micron Corporation),
Examples include an apparatus in which the grinding air pressure is reduced, a hybridization system (Nara Machinery Co., Ltd.), an automatic mortar, and the like as compared with the case of ordinary pulverization using a mill (Nippon Pneumatic Industries).

As described above, a fluidizing agent may be further added to the toner into which the charge control agent has been injected in this step, and mixed. As a mixing method, a general mixing apparatus such as a V blender and a ball mill may be used.

It is preferable that the charge control agent turns into primary particles of 1 μm or less after the above-mentioned treatment. In addition, if the surface is partially fused with resin due to heat, the charge control agent separates from the toner surface during running, preventing the drum or the carrier of the two-component developer from moving to the sleeve in the one-component development process. It is possible to expect a long-life, high-durability toner. The ratio between the charge control agent and the colored resin particles should ideally cover the surface in a monomolecular manner, but is usually 0.01 to 1
0 parts by weight, preferably 0.1 to 5 parts by weight (colored resin particles 1
00 parts).

In the present invention, “mechanical driving” means giving mechanical energy to the colored resin particles and the charge control agent,
This means that the charge control agent is immobilized on the surface of the colored resin particles. Also, in addition to mechanical energy, auxiliary heating,
Heat energy can be applied to fix the charge control agent.

The following are examples of the charge control agent in the present invention.

Nigrosine, an azine dye containing an alkyl group having 2 to 16 carbon atoms (JP-B-42-1627);
Basic dyes (e.g., CIBasic Yellow 2 (CI41000)
, CIBasic Yellow 3, CIBasic Red 1 (CI4516
0), CIBasic Red 9 (CI42500), CIBasic Violet 1
(CI42535), CIBasic Violet 3 (CI42555), CI
Basic Violet 10 (CI45170), CIBasic Violet14 (C.
I.42510), CIBasic Blue1 (CI42025), CIBasic B
lue 3 (CI51005), CIBasic Blue 5 (CI42140),
CIBasic Blue 7 (CI42595), CIBasic Blue 9 (C.
I.52015), CIBasic Blue 24 (CI52030), CIBasic
Blue 25 (CI52025), CIBasic Blue 26 (CI4404
5), CIBasic Green 1 (CI42040), CIBasic Green
4 (CI42000), etc., lake pigments of these basic dyes (as the lacking agent, phosphotungstic acid, phosphomolybdic acid, phosphotungsten molybdic acid, tannic acid, lauric acid, gallic acid, ferricyanide, ferrocyanide) ), CISoventBlack 3 (CI26150), Hansa Yellow G (CI11680), CIMODlant Black 11, CI
Pigment Black 1, benzolmethyl-hexadecyl ammonium chloride, decyl-trimethylammonium chloride, or dialkyltin compounds such as dibutyl or dioctyl, dialkyltin borate compounds,
Polyamine resins such as guanidine derivatives, amino group-containing vinyl polymers and amino group-containing condensation polymers, JP-B-41-20153 and JP-B-43-27596.
And metal complexes of monoazo dyes described in JP-A-44-6397 and JP-A-45-26478. Tokiko 55-42
No. 752, JP-B-58-41508, JP-B-58-7
No. 384, JP-B-59-7385, metal complexes of salicylic acid, dialkylsalicylic acid, naphthoic acid, dicarboxylic acids such as Zn, Al, Co, Cr and Fe, and sulfonated copper phthalocyanine pigments.

In the present invention, a fluidizing agent may be mixed with the toner into which the charge controlling agent has been injected. As the fluidizing agent in this case, known materials such as titanium oxide, hydrophobic silica, zinc stearate, and magnesium stearate are used.

In addition, if necessary, a protective film for preventing a phenomenon that the toners are aggregated and solidified during storage is provided.
Fine resin particles with high g, for example, PMMA (polymethyl methacrylate), PTFE (polytetrafluoroethylene), submicron fine particles of PVDF (polyvinylidene fluoride), polyolefins, fatty acid esters, fatty acid metal salts, higher alcohols, paraffin wax It is possible to apply a release agent of the same type to the surface in the same manner as the charge control agent, but in this case, it is important to atomize by means of recrystallization, pulverization, emulsification and the like.

As a result, a highly durable, high-quality electrophotographic toner having excellent fluidity, uniform chargeability of the developer, generation of ultrafine particles due to pulverization in the developing section, and excellent offset resistance is provided. .

[0075]

【Example】

Example 1 A polyacrylic acid (average molecular weight: 20) was placed in a cylindrical separable flask equipped with an inert gas inlet tube, a stirring blade (using an angled fan turbine), a condenser, and a dropping funnel.
10) 3 parts by weight, 100 parts by weight of methanol and 30 parts by weight of isopropyl alcohol were added and dissolved with stirring. Then, nitrogen gas was blown into the solution to reduce the residual oxygen concentration in the system to 0.1% or less.

While blowing in nitrogen gas, 30 parts by weight of styrene monomer, 10 parts by weight of n-butyl methacrylate,
0.2 parts by weight of 1,3-butanediol dimethacrylate and 0.01 parts by weight of carbon tetrachloride were introduced from a dropping funnel to obtain a uniform transparent solution.

The system was immersed in constant temperature water at 40 ± 0.1 ° C., and the temperature was further increased while stirring at 100 rpm for 1 hour.

A solution in which 0.5 parts by weight of benzoyl peroxide was dissolved in 5 parts by weight of styrene monomer was added dropwise over about 30 minutes to prepare a thinly cloudy dispersion.
The mixture was kept at 40 ° C. for another 2 hours, and the clouding became more intense.

Then, the temperature of the hot water tank was gradually raised to 60 ° C. over 1 hour, and after 30 minutes, the liquid obtained by dispersing 0.5 part by weight of hydrophobic colloidal silica in 5 parts by weight of methanol was added. It was dropped. At this time, the polymerization rate was measured by gas chromatography using ethylbenzene as an internal standard.
Confirmed that it has reached. The temperature of the system was further raised to 85 ° C., and the reaction was continued for 1 hour.
0.8 parts by weight of rudimethacrylate was added all at once using a syringe. Thereafter, the reaction was continued for 20 hours to produce a polymer particle dispersion.

The particles obtained were dv = 6.31 μm, dn
= 6.06 µm, dv / dn = 1.041, and the weight-average molecular weight Mv3 of the THF-soluble component
520,000, number average molecular weight Mn 25,000, Mv / Mn =
Was 14.1.

The unextracted THF was 35% and the Tg was 65%.
° C softening temperature 72 ° C Outflow starting temperature was 140 ° C.

On the other hand, after heating and dissolving Solvent Black 3 in 1.0 part by weight and 20 parts by weight of methanol, the mixture was cooled to 1 μm.
Was added to 135 parts by weight of the polymer dispersion liquid.

After stirring at 50 ° C. for 1 hour, the dispersion was cooled to room temperature, centrifuged and the supernatant was removed to remove methanol.
3 re-dispersion in a mixed solvent of 50 parts by weight of water and 3 parts by weight of water
Times. After filtration, the resultant was air-dried and dried under reduced pressure at 40 ° C. for 6 hours to obtain resin particles colored black.

To 100 parts by weight of the colored resin particles, 0.5 part by weight of Spiron Black TRH (manufactured by Hodogaya Chemical) is used.
After stirring for 5 minutes with a Star Blender, the mixture was treated with Hybridization NHS-1 (manufactured by Nara Machinery Co., Ltd.) at 7000 rpm for 5 minutes to obtain a toner of the present invention.

Analysis by a coater multisizer revealed that the volume average particle diameter dv was 6.50 μm, the individual average particle diameter was 5.91 μm, and dv / dn = 1.10.

About the present toner Rico-copier FT-55
As a result of evaluating the image by using the number 10, the resolution was 7.1 lines /
mm, and the image did not deteriorate even after running 30,000 sheets, and a clear black image was kept as it was at the initial stage.

Comparative Example 1 A polymer dispersion was prepared in the same manner as in Example. However, the crosslinking agent 1,3-butanediol dimethacrylate was not used, and no post-addition was performed when the temperature of the system was raised to 65 ° C.

The particles obtained had dv = 7.93 μm, dn
= 7.28, dv / dn = 1.09, and the weight average molecular weight Mw = 3.2 of the THF dissolved component.
Mn = 12,000, Mw / Mn = 2.7.
The unextracted THF was 0%, and the Tg was determined by DSC.
59.3 ° C., softening temperature 63 ° C., outflow starting temperature 101
° C.

This resin dispersion was subjected to a dyeing treatment and a surface treatment step in the same manner as in the example, and dv = 8.12 μm and dn =
A toner which was uniformly colored from the particle surface to the inside with a particle diameter of 7.06 μm and dv / dn = 1.15 was obtained. As a result of the evaluation of the image by the Rico-copier FT-5510 using this toner, the hot offset was severe, and the image evaluation was stopped at the initial 20 sheets due to contamination of the fixing roller.

Comparative Example 2 A polymer dispersion was produced in the same manner as in Example. However, polymerization was carried out by adding 2.0 parts by weight of the crosslinking agent to the initial monomer composition. After the system was heated to 65 ° C., no post-addition was performed.

One hour after the temperature of the polymerization system was raised to 65 ° C., aggregation of the system was observed, and after 3 hours, stirring became impossible, and polymer particles were not obtained.

[0092]

As described above, the polymer particles of the present invention have a narrow particle size distribution and a wide molecular weight distribution, and the toner for electrophotography using this has a short charge amount distribution. A sharp image can be formed with the image forming apparatus, and the initial high image quality can be maintained even after repeated use.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-64-26617 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08F 2/00-246/00 G03G 9 / 08

Claims (1)

(57) [Claims] 1. A method in which a vinyl monomer dissolves, but a polymer formed swells or hardly dissolves in a hydrophilic organic liquid, and a vinyl monomer and a crosslinking agent are dissolved in the hydrophilic organic liquid. When polymerizing using a polymer dispersion stabilizer,
Up to 10% conversion, use a crosslinking agent for the vinyl monomer.
This is a method for producing polymer particles by adding a crosslinking agent of 10% by weight or less at a time, then dividingly or continuously adding the crosslinking agent, and then producing polymer particles. A method for producing polymer particles, comprising adding an agent.