JPH0929092A - Production of microcapsule particles and production of toner for electrophotography - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance the physical strength of microcapsule particles by using a non-gel like org. solvent-soluble acidic group-containing binder resin having a partial crosslinking structure as a binder resin when the microcapsule particles are produced by inverting an org. solvent soln. of a binder resin in which a solid substance is dispersed in phase by an aq. medium to emulsify the same. SOLUTION: When microcapsule particles are produced by inverting an or. solvent soln. of a binder resin B in which a solid substance A is dispersed in phase by an aq. medium to emulsify the same, a nongel like org. solvent- soluble acidic group-containing binder resin having a partial crosslinking structure is used as the binder resin B. Or a non-gel like org solvent-soluble acidic group-containing binder resin having no crosslinking structure is used as the binder resin B and, in this case, an org. solvent soln. containing an amino coupling compd. and an emulsifier is used to perform phase inverting emulsification to obtain microcapsule particles. As the solid substance A, a coloring agent is used and a liquid medium is removed from the dispersion obtained by phase inverting emulsification to dry the dispersion to produce toner for electrophotography.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to paints, inks,
It relates to a method for producing fine particles that can be used as capsule particles containing solid substances, such as electrostatic toner, cosmetics, and fiber colorants. More specifically, it develops electrostatic latent images in electrophotography, electrostatic recording, electrostatic printing, etc. The present invention relates to a method for producing microcapsule particles containing a colorant such as a dye or a pigment, which can be suitably used for the dry toner.

[0002]

2. Description of the Related Art As one of the methods for producing capsule microparticles containing a colorant, a phase inversion emulsion granulation method, which is a physicochemical method, is known. In this phase inversion emulsification granulation method, a dispersion in which a colorant is dispersed in a solution of a polymer resin serving as a binder in an organic solvent is prepared, and water or an organic solvent or a dispersion stabilizer is added separately. A so-called aqueous medium such as water is prepared, and both are mixed with stirring to prepare capsule microparticles containing a colorant stably dispersed in the aqueous medium. The particle size of the capsule microparticles obtained by such a method can be controlled to an arbitrary average particle diameter in the range of 0.1 to 100 microns by appropriately selecting the granulation conditions, and This is a major factor that makes the field of use broad.

However, the fine particles obtained by this phase inversion emulsion granulation method have many characteristics,
There were problems that the physical strength of the particles was low and the thermal physical properties were not sufficient. For example, when the toner is used as an electrophotographic toner, it has some problems.

In the electrophotographic method, an electrostatic latent image is formed on a photoreceptor according to an analog signal or a digital signal of an original image, the electrostatic latent image is developed with toner particles, and then the image is formed on the photoreceptor. The formed toner particles are transferred to a transfer material such as paper or sheet, and the toner particles are fixed by using heat, pressure or the like to obtain a permanent image. At that time, in order to obtain a permanent image with sufficient image density and high resolution, it is necessary that toner particles of a predetermined weight adhere faithfully to the electrostatic latent image formed on the photoconductor. .

For this reason, practical toners are required to have the property of rapidly exhibiting a sufficient amount of charge in the particles by friction. Usually, this friction is performed by contact mixing with a carrier in the two-component developing system, and is utilized by utilizing contact friction with a blade in the one-component developing system. Here, in both of the one-component developing method and the two-component developing method, it is necessary to develop a sufficient charge amount in the toner particles, and therefore excessive mechanical stress is generated in the toner particles, and particle strength capable of withstanding the mechanical stress is required. ing. If the particle strength is insufficient, the toner particles will be destroyed, and the disadvantage that a uniform charge amount cannot be imparted will occur. The particles obtained by the phase inversion emulsification granulation method are particles in which polymer resins are entangled with each other, and do not necessarily have mechanically sufficient strength. In that case, there is a problem that particle destruction easily occurs.

Further, the fixing property is also an important design factor in obtaining a practical toner. In the heat roller fixing method which is generally widely used, the heat roller is pressed against the image-formed toner particles to heat-melt the toner particles, whereby the toner particles are fixed to a transfer material such as paper. At that time, if the viscoelasticity of the binder resin component of the toner particles is insufficient, a part of the resin is separated from the toner body and transferred onto the heating roller at the time of heat melting, which is a so-called offset phenomenon that induces image contamination. Will cause. Alternatively, even if hot offset can be prevented, if the viscoelasticity is insufficient, a large amount of heat at high temperature is required to melt the resin, and in practice it becomes difficult to fix it on paper and the toner cannot be fixed. Will end up. The particles obtained by the phase inversion emulsification method have a problem that this offset phenomenon easily occurs and it is difficult to impart sufficient viscoelasticity.

[0007]

In view of the above circumstances, the present invention provides a method for producing microcapsule particles which are excellent in physical strength and thermal physical properties by phase inversion emulsification granulation, and more specifically, An object of the present invention is to provide a manufacturing method by phase inversion emulsification granulation of a toner for electrophotography which has viscoelasticity which is excellent in mechanical particle strength capable of withstanding triboelectric charging as toner and excellent in fixing property.

[0008]

As a result of intensive studies, the inventors of the present invention have solved the above problems. That is, the present invention provides the following inventions in order to solve the above problems.

In the method for producing fine capsule particles obtained by phase inversion emulsification of an organic solvent (C) solution of a binder resin (B) in which a solid substance (A) is dispersed, the binder resin As (B), a non-gelled organic solvent-soluble acidic group-containing binder resin having a partially crosslinked structure is used,
And phase inversion emulsification using an organic solvent solution containing an emulsifier and / or a dispersion stabilizer, or as the binder resin (B),
A non-gelling organic solvent-soluble acidic group-containing binder resin having no crosslinking structure is used, and an amino coupling compound, an emulsifier and / or a dispersion stabilizer sufficient to form the partial crosslinking structure are used. A method for producing microcapsule particles, which comprises performing phase inversion emulsification using an organic solvent solution containing the same (referred to as a first invention).

In the method for producing fine capsule particles obtained by phase inversion emulsification of an organic solvent (C) solution of a binder resin (B) in which a solid substance (A) is dispersed, in the aqueous medium, the binder resin As (B), phase-inversion emulsification is performed using an acidic group-containing binder resin that has a partially crosslinked structure and is soluble in a non-gelled organic solvent that can become self-water dispersible by neutralization, or As the agent resin (B), an acidic group-containing binder resin having no crosslinked structure, soluble in a non-gelled organic solvent and capable of becoming self-water dispersible by neutralization, and the partial crosslinked structure A method for producing microcapsule particles, which comprises performing phase inversion emulsification using an organic solvent solution containing an amino coupling compound sufficient to form (a second invention).

Toner particles composed of binder resin particles containing a colorant by subjecting a solution of the binder resin (B) in which the colorant (a) is dispersed in an organic solvent (C) to phase inversion emulsification in an aqueous medium. In the method for producing an electrophotographic toner to obtain a dry toner by removing the aqueous medium from the aqueous dispersion, the binder resin (B) is a non-gelled non-gelled structure having a partially crosslinked structure. Phase-inversion emulsification is performed using an organic solvent-soluble binder resin containing an acidic group and an organic solvent solution containing an emulsifier and / or a dispersion stabilizer, or a crosslinked structure is formed as the binder resin (B). An organic solvent solution containing an amino coupling compound, an emulsifier and / or a dispersion stabilizer, which does not have a non-gelled organic solvent-soluble acidic group-containing binder resin and is sufficient to form the partially crosslinked structure Phase inversion emulsification using Method of manufacturing electrophotographic toner as symptoms (. Referred to as a third invention).

Toner particles composed of binder resin particles containing a colorant by subjecting a solution of the binder resin (B) in which the colorant (a) is dispersed in an organic solvent (C) to phase inversion emulsification in an aqueous medium. In the method for producing an electrophotographic toner to obtain a dry toner by removing the aqueous medium from the aqueous dispersion, the binder resin (B) is a non-gelled non-gelled structure having a partially crosslinked structure. Phase-inversion emulsification is performed using an acidic group-containing binder resin that is soluble in an organic solvent and may become self-dispersible by neutralization, or the binder resin (B) does not have a crosslinked structure, A gel-like organic solvent-soluble, which may be self-dispersible in water by neutralization, using an acidic group-containing binder resin, and the organic solvent solution containing an amino coupling compound sufficient to form the partially crosslinked structure, Characterized by using phase inversion emulsification Method of manufacturing electrophotographic toner (. Referred to as a fourth invention).

The above-mentioned first to fourth inventions are all related to a method for obtaining particles having an appropriate strength which can withstand mechanical stress by a phase inversion emulsification method.

The binder resin used in the present invention is required to contain an acidic group, for example, a functional group having anion forming ability such as a carboxyl group, a phosphoric acid group and a sulfonic acid group in its molecular chain.

Examples of the binder resin containing a functional group capable of forming anions include epoxy resins, urethane resins, polyamide resins, acrylic resins, alkyd resins and polyester resins. These may be used alone or in combination of two or more. Among them, an acrylic resin, in particular styrene /
Acrylate copolymer resins are preferred.

The binder resin has a molecular weight at a level required to exhibit sufficient mechanical strength, usually has a weight average molecular weight of 3,000 to 200,000, and an acrylic resin has a molecular weight of 5,000 to 150,000. And,
In the DSC measurement, the glass transition temperature (Tg) is 50 to
It is preferably 100 ° C., and for heat roll fixing, it is preferably about 60 to 80 ° C.

Taking an acrylic resin binder as an example, a polymer resin obtained by polymerizing a monomer such as (meth) acrylic acid ester can be given as a representative example. Specifically, for example, styrene, Styrenes such as α-methylstyrene, chlorostyrene and vinylstyrene,
Monoolefins such as ethylene, propylene, butylene, isobutylene, diolefins such as butadiene and isoprene, vinyl acetate, propion vinyl, vinyl butyrate,
Vinyl esters such as vinyl benzoate, methyl acrylate, ethyl acrylate, butyl acrylate, octyl acrylate, phenyl dodecyl acrylate, methyl methacrylate, ethyl methacrylic acid butyl methacrylate, α-, such as dodecyl methacrylate. Acrylic monomers such as vinyl ethers such as methylene aliphatic monocarboxylic acid esters, vinyl methyl ether, vinyl ethyl ether, vinyl butyl ether, vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone, vinyl propenyl ketone, acrylic acid, methacrylic acid , Crotonic acid, itaconic acid, maleic acid, fumaric acid, itaconic acid monobutyl, maleic acid monobutyl, acid phosphooxyethyl methacrylate, acid phosphooxypropyl methacrylate By copolymerizing at least one monomer selected from acid group-containing monomers such as 3-chloro-2-acrylamido-2-methylpropanesulfonic acid and 2-sulfoethylmethacrylate, a functional group having anion-forming ability is obtained. The binder resin may be contained.

Further, when the acrylic binder resin is described in detail, a polymer unsaturated group-containing oligomer having an acid group can also be used as a copolymerization component, such as maleic anhydride, fumaric acid and tetrahydrophthalic anhydride. Acid, endomethylenetetrahydromaleic anhydride, α-terpinene maleic anhydride adduct and the like and monoallyl ether of triol, polycondensation of pentaerythrite diallyl ether or allyl glycidyl ether or vinyl-modified polyesters obtained by addition condensation, Dimethylolpropionic acid, glycerin monoallyl ether, 1,
2 Vinyl modified urethanes obtained by addition polymerization of butadiene polyol and diisocyanate, vinyl modified epoxies obtained by adding a glycidyl group-containing monomer to a carboxyl group-containing vinyl copolymer, and the like.

As the polymerization initiator used to obtain such a polymer resin, of course, usual ones can be used, but for example, benzoyl peroxide, di-t-butyl peroxide, cumene hydroperoxide, t-butyl. Mention may be made of various peroxides such as peroxide or 2-ethylhexanoate; or various azo compounds such as azobisisobutyronitrile or azobisisovaleronitrile.

The polymer resin may be obtained by solution polymerization in an organic solvent, suspension polymerization, emulsion polymerization, or bulk polymerization.

As the polyester-based resin binder, in the condensation of a polyol and a polybasic acid, an acid group can be easily introduced into an ordinary polyester resin by using an excessive amount of a dibasic acid such as phthalic acid. You can

In the method for producing microcapsule particles of the present invention, an amino coupling agent compound is used as an essential component. Examples of the amino coupling agent compound include aminosilane coupling agents, aminotitanium coupling agents, aminoaluminum coupling agents, and the like. Among them, N- (β-aminoethyl) -γ-aminopropyl (dimethoxy) methylsilane, N -(Β-aminoethyl) -γ-aminopropyltrimethoxysilane, γ-
An aminosilane coupling agent such as aminopropyltriethoxysilane can be preferably used.

When such an amino coupling agent compound is combined with a binder resin containing a functional group having anion-forming ability such as the above-mentioned acidic group to carry out phase inversion emulsification granulation, surprisingly, inter-particle Without causing agglomeration of
It was found to act as a crosslinking agent for the binder resin in the particles.

The amount of the amino coupling agent compound used in the present invention is 0.01 to 7% by weight based on the binder resin.
It is preferably 0.1 to 3% by weight. Within this range, when the microcapsule particles are used in a toner application, heat at a high temperature and a large capacity for melting the resin is unnecessary, and viscoelasticity characteristics preferable for fixing can be obtained. Is easily obtained.

In the production of the microcapsule particles of the present invention, as the solid substance (A), known and conventional substances such as pharmaceuticals, cosmetics, perfumes, foods, coloring agents and the like can be used. In producing the electrophotographic toner, the colorant (a) is used as the solid substance (A).

As the colorant in this case, a known and commonly used colorant can be used. Specifically, for example, carbon black, magnetic powder, nigrosine dye, aniline blue, calcoil blue, chrome yellow, ultramarine blue. , DuPont Oil Red, Quinoline Yellow, Methylene Blue Chloride, Phthalocyanine Blue, Malachite Green Oxalate, Lamp Black, Rose Bengal, C.I. I. Pigment Red 122, C.I. I. Pigment Yellow 97, C.I. I. Pigment Blue 15, ferrosoferric oxide, ferric oxide, iron powder, zinc oxide, selenium, etc. can be used, and they can be used alone or in combination of two or more.

In the present invention, the toner obtained may be magnetic toner particles in which magnetic fine particles are dispersed in a binder resin. As the magnetic substance fine particles, any ferromagnetic substance that is normally used can be used.

Specific examples of the magnetic material include magnetic metals such as iron, cobalt and nickel, alloys of these, metal oxides such as cobalt-added iron oxide and chromium oxide, Mn / Zn ferrite, Ni / Zn ferrite and the like. Various kinds of ferrite,
In addition to magnetite, hematite, etc., the surface of these, silane coupling agent, aluminum coupling agent,
Powders such as those treated with a surface treatment agent such as a titanium coupling agent or those coated with a polymer can be used.

The weight ratio of the solid substance (A) and the binder resin (B) is not particularly limited, but in the case of toner and other cases, when the total weight thereof is 100, It is preferable that the colorant is 3 to 30% by weight.

The phase inversion emulsification method in the method for producing the microcapsule particles of the present invention is not particularly limited,
For example, the following method can be given as a step-by-step description.

In carrying out phase inversion emulsification, there are a method of using an emulsifier and a dispersion stabilizer as essential components and a method of using a binder having an emulsifying and dispersing function as a binder without using them.

Further, if the resin component is finally partially crosslinked, particle strength capable of withstanding mechanical stress can be obtained. Therefore, partial crosslinking of the resin component may be carried out at any stage where the microcapsule particles are obtained. Therefore, even if the binder resin partially crosslinked in advance is used, the uncrosslinked binder resin may be used so as to be partially crosslinked in any step of forming the microcapsule particles.

Hereinafter, an example of a method for producing the microcapsule particles adopting the latter partial crosslinking method by phase inversion emulsification will be described in more detail.

First, an organic solvent solution of the binder resin in which the solid substance (A) is dispersed, which may optionally contain an emulsifier and / or a dispersion stabilizer, is prepared, and amino coupling is carried out. The drug compound is dissolved and dispersed.

Examples of the organic solvent that can be used in preparing the organic solvent solution include various aromatic hydrocarbons such as toluene, xylene or benzene; various alcohols such as methanol, ethanol, propanol or butanol; cellosolve. Or various ether alcohols such as carbitol; various ketones such as acetone, methyl ethyl ketone or methyl isobutyl ketone; various esters such as ethyl acetate or butyl acetate; or various ether esters such as butyl cellosolve acetate And the like.

As the organic solvent, it is preferable to use a hydrophobic organic solvent among the above-mentioned ones as an essential component,
Above all, it is more preferable to use a hydrophobic organic solvent as a main component and a hydrophilic organic solvent together, because phase inversion emulsification can be carried out smoothly.

At this time, the non-volatile content of the organic solvent solution is not particularly limited, but is usually 10 to 70% by weight.

Then, an organic solvent solution of the binder resin, which may contain a dispersion stabilizer, in which the solid substance (A) obtained above and the amino coupling agent compound are dispersed, is subjected to phase inversion emulsification in an aqueous medium. By doing so, granulation of fine particles in an aqueous medium is performed. In this case, of course, an aqueous medium may be added to the organic solvent solution for phase inversion emulsification, or the organic solvent solution may be added to the aqueous medium for phase inversion emulsification.

In order to smoothly carry out this phase inversion emulsification granulation, an emulsifier and / or a dispersion stabilizer can be contained in the organic solvent solution and / or the aqueous medium.

As the dispersion stabilizer, a water-soluble polymer compound is generally used, and examples thereof include polyvinyl alcohol, polyvinylpyrrolidone, hydroxyethyl cellulose, carboxymethyl cellulose and cellulose gum. Examples of the emulsifier include anionic surfactants such as sodium dodecylbenzenesulfonate, sodium lauryl sulfate, sodium dodecyldiphenyloxide disulfonate, nonionic surfactants such as polyoxyethylene lauryl ether, polyoxyethylene ninyphenol ether, and the like. And these emulsifiers and dispersion stabilizers can be used in combination.

The aqueous dispersion of the microcapsule particles thus obtained is spherical particles of the binder resin in which the solid substance (A) is encapsulated, and the inside of the particles is partially crosslinked with the amino coupling agent. It is an aqueous dispersion of fine particles stably dispersed in the prepared aqueous medium.

If a self-water-dispersible resin is used as the binder resin, phase inversion emulsion granulation can be carried out without using a dispersion stabilizer or an emulsifier.

The self-water-dispersible resin is a resin containing in its molecule a functional group capable of becoming a hydrophilic group by neutralization, and some or all of the functional groups capable of becoming hydrophilic are neutralized by a neutralizing agent. In this case, the resin has the ability to form a stable aqueous dispersion without using an emulsifier or a dispersion stabilizer.

Examples of the functional group capable of becoming a hydrophilic group by neutralization in this resin include a so-called acidic group such as a carboxyl group, a phosphoric acid group and a sulfonic acid group. Taking a carboxy group-containing anionic resin as an example, The content of the carboxyl group of the resin, which can become an anionic hydrophilic group by neutralization, is not particularly limited,
An acid value of about 40 or more is preferable because particle formation by the phase inversion emulsification method is easy. Particularly preferably, the acid value is 50 to 1.
50.

The neutralizing agent used in the above self-water-dispersible resin is not limited to its kind as long as the resin exhibits hydrophilicity to the extent that it can be self-water-dispersed in an aqueous medium. In carrying out the present invention using an anion type resin, a compound which easily forms a cation ion in water can be used.

Since an amino coupling agent is used in the present invention, it can be used as a neutralizing agent.
It is preferable to use not only the amino coupling agent but also a usual neutralizing agent having no coupling function.

Specific examples of effective neutralizing agents include, for example, sodium silicate, potassium silicate, sodium hydroxide, potassium hydroxide, lithium hydroxide, dibasic sodium phosphate, tribasic sodium phosphate and dibasic sodium phosphate. Ammonium phosphate, tribasic ammonium phosphate, sodium metasilicate,
Metal basic compounds such as sodium carbonate, ammonia, or mono, di, or trimethylamine, mono, di, or triethylamine, mono, or diisopropylamine,
Mention may be made of organic amine compounds such as n-butylamine, mono-, di- or triethanolamine, mono-, di- or triisopropanolamine, ethyleneimine, ethylenediimine.

As the neutralizing agent used for neutralizing the anionic resin, for example, a metal basic compound has an advantage that it can narrow the particle size distribution of the microcapsule particles obtained during phase inversion emulsification. On the other hand, the organic amine compound has an advantage that the environment resistance property can be improved.

The phase-inversion emulsification granulation using the self-water-dispersible resin as a binder resin is usually carried out by adding a neutralizing agent in a solution of the self-water-dispersible resin in an organic solvent in which the solid substance (A) is dispersed. A self-water-dispersible resin organic solvent in which the amino coupling agent compound is added and dispersed, and then mixed with an aqueous medium for phase inversion emulsification, or the solid substance (A) and the amino coupling agent compound are dispersed. The solid substance (A) is obtained by mixing the solution and an aqueous medium containing a neutralizing agent and subjecting the mixture to phase inversion emulsification.
It can be an aqueous dispersion of spherical capsule particles in which the binder resin encapsulating is partially crosslinked. In the case of an electrophotographic toner, the colorant (a) is used as the solid substance (A), and when it is used as powder fine particles like a dry toner, the aqueous medium is removed from the aqueous dispersion of the capsule particles. It can be easily made into powder particles by drying.

From the aqueous dispersion, it is preferable to remove only the organic solvent and then the water so that the fusion of toner particles can be further reduced. If necessary, after removing the organic solvent, a neutralizing agent of the opposite polarity to that used to make the binder resin self-dispersible in water is added to the aqueous dispersion to perform reverse neutralization, and then filtered. It can also be dried. Further, the acidic groups in the binder resin can be neutralized again with a neutralizing agent having the same polarity as that used to obtain the dispersion liquid.

In order to produce toner particles, in the phase inversion emulsification granulation method, a separate step such as a water washing step for separately removing the dispersion stabilizer is not required, and the productivity is excellent. A phase inversion emulsification method using a self-water-dispersible resin as a binder, which does not substantially use an emulsifier or a dispersion stabilizer, is preferable.

The phase inversion emulsification method utilizing a self-water-dispersible resin without using an emulsifier or a dispersion stabilizer is compared with other toners of the phase inversion emulsification method, and the emulsifier or the dispersion stabilizer is added to the final toner powder. Therefore, the dry toner having more stable charging characteristics can be obtained.

In obtaining the aqueous dispersion of toner particles used in the present invention, an auxiliary agent such as wax or a charge control agent may be added, if necessary, in any step of its production.

Examples of the auxiliaries include waxes such as polyethylene wax, polypropylene wax and paraffin wax, metal soaps, lubricants such as zinc stearate,
Alternatively, an abrasive such as cerium oxide or silicon carbide, a copper phthalocyanine, perylene, quinacridone, an azo pigment, an azo metal-containing dye, a charge control agent such as an azochrome complex, etc. may be mentioned.

As the particle size of the toner powder of the present invention, any size can be selected within a practical level as a toner. The volume average particle diameter is 3 to 30 μm, preferably 4 to 12 in view of the matching property with the current machine.
The range of μm is preferable.

The electrophotographic toner of the present invention can be used as a non-magnetic one-component toner or a magnetic one-component toner, or as a two-component developer when combined with a carrier, and is particularly excellent as a two-component developer. The characteristics can be obtained.

Any known carrier may be used as the carrier. Examples of the carrier include iron, nickel, copper, zinc,
Powders of metals such as cobalt, manganese, chromium, rare earths and alloys or oxides thereof, surface-treated glass, silica and the like can be used. Of course, resin-coated carriers such as acrylic resin-coated carriers, fluororesin-coated carriers, and silicone resin-coated carriers can also be used. As the carrier, for example, a carrier of about 20 to 200 microns is used.

When a two-component electrostatic image developer is obtained from the toner obtained in the present invention and a carrier, for example, the toner is mixed in a ratio of 1 to 15 parts by weight of toner per 100 parts by weight of carrier. You can use it.

[0059]

BEST MODE FOR CARRYING OUT THE INVENTION A preferred embodiment of the present invention will be described below by taking an electrophotographic toner as an example.

First, styrene, which has an acid value of 50 to 150, a weight average molecular weight of 20,000 to 60,000, and a glass transition temperature (Tg) of 50 to 100 ° C., can be self-dispersible in water by neutralization.
A hydrophobic organic solvent solution of a (meth) acrylic acid ester- (meth) acrylic acid copolymer is obtained.

Next, a hydrophilic organic solvent and a pigment as a colorant are added to the solution and mixed, and then an aqueous metal basic compound solution and an aminosilane coupling agent are further added. At this time, the amount of the coupling agent added is in the range of 0.1 to 3% by weight with respect to the resin nonvolatile content so that the binder resin remains partially crosslinked. The metal basic compound is used in combination with the coupling agent so that the resin can be self-dispersed in water. Mill base is prepared in this way,
While stirring it, water was added dropwise thereto to obtain an aqueous dispersion of partially crosslinked toner particles.

Further, the organic solvent is removed from this dispersion by performing vacuum distillation so that the temperature becomes lower than the softening temperature of the toner particles, an aqueous acid solution is added thereto, and filtration washing is carried out.
The toner particles are redispersed in water, the organic amine compound is added thereto, and the mixture is thoroughly stirred, then filtered and dried, and the pigment is included in the partially crosslinked binder resin having a volume average particle diameter of 4 to 12 μm. To obtain a dry toner powder composed of toner particles.

The dry toner powder of 1 to 10 parts by weight is added to 100 parts by weight of carrier particles to obtain a two-component type electrophotographic developer.

[0064]

The present invention will be described more specifically below with reference to examples of the present invention. However, the invention is not limited to these examples.

Example 1 200 g of methyl ethyl ketone
Was placed in a reactor and heated to 80 ° C. Then, the mixture in the proportions shown below was added dropwise over about 2 hours. Meanwhile, the reaction was carried out in a nitrogen stream.

Methacrylic acid 45 g Styrene 207 g 2-Ethylhexyl acrylate 33 g Methyl methacrylate 15 g Perbutyl O [manufactured by Nippon Shokubai Co., Ltd.] 3 g Methyl ethyl ketone 12 g

One hour after the completion of the dropping of the above mixture, 0.25 g of perbutyl O was additionally added, and then 0.25 g was added within 2 hours and the reaction was continued for 24 hours. After completion of the reaction, a styrene-acrylic copolymer resin solution having a nonvolatile content of 54% by weight and capable of becoming self-dispersible in water was obtained. This resin had an acid value of 100 and a weight average molecular weight of 40,000.

200 g of this copolymer solution, 35 g of isopropyl alcohol, and 12.0 g of "MA-100" (carbon black manufactured by Mitsubishi Kasei Co., Ltd.) were kneaded with "Eiger M-250VSE-EXJ" (manufactured by Eiger, USA). After mixing for 1 hour in a kneading machine), 11.5 g of a 1N caustic soda aqueous solution and N- (β-aminoethyl) -γ-aminopropyltrimethoxysilane as an amino coupling agent compound [Toray Dow Corning Silicone Co., Ltd. SH6020] 0.5 g, and using a three-one motor, water was added dropwise while stirring at 350 rpm to carry out phase inversion emulsification, and a toner particle aqueous solution containing a self-water dispersible resin containing a colorant was prepared. A dispersion was obtained. When the toner particles were measured with a Coulter counter, they were toner particles having an average particle diameter of 8 microns. Further, the above-mentioned toner particle aqueous dispersion was sampled on a slide glass, a cover glass was placed on the slide glass, the particles were strongly pressed with a finger to spread the particle dispersion, and the particles were observed with an electron microscope. It was confirmed to be spherical toner particles.

Next, the organic solvent was removed by vacuum distillation so that the temperature became lower than the softening point of the toner particles, and the pH was adjusted to 6
A 0.01N aqueous hydrochloric acid solution was added to the mixture until filtration and filtered and washed, and then the toner particles were returned to water to obtain an aqueous dispersion of toner particles. To this aqueous dispersion of toner particles, 0.31 g of triethylamine was added and sufficiently stirred. Then, it was filtered and treated with a freeze dryer for 3 days to obtain a dry toner. This toner had excellent fluidity, and no aggregation of particles was observed.

The melt viscosity of this toner was measured by a flow tester (manufactured by Shimadzu Corporation) and found to be 1000.
It showed 222 ° C. at 00 poise.

The dry toner thus obtained has an average particle size of 80 μm.
When a developer was prepared by mixing and agitating 5 parts by weight with 100 parts by weight of a ferrite carrier of m, and a copying test was carried out by a commercially available electronic copying machine, hot offset did not occur and a uniform image density was obtained. A clear image faithful to 20,000 or more originals having the above was obtained.

Comparative Example 1 An aqueous dispersion of toner particles was prepared without adding the amino coupling agent compound used in Example 1. That is, toner particles in which the inside of the toner particles were not crosslinked were prepared. When measured with a Coulter Counter, the average particle size was 8 micron toner particles. As in Example 1, the toner particle aqueous dispersion was sampled on a slide glass, the cover glass was placed on the slide glass, and the particles were strongly pressed with a finger to spread the particle dispersion, and the particles were observed with an electron microscope. Particles were observed and confirmed to be mechanically weak particles.

Further, when the melt viscosity of the dry toner was measured with a flow tester (manufactured by Shimadzu Corporation), it was 143 ° C. at 100000 poise.

The obtained dry toner was treated with an average particle size of 80 μm.
When 5 parts by weight of 100 parts by weight of the ferrite carrier of m were mixed and stirred to adjust the developer, and a copying test was conducted using a commercially available electronic copying machine, hot offset occurred from the initial stage, Only an image with severe dirt was obtained.

[0075]

According to the invention of claim 1, since the solid substance is used to produce the microcapsule particles dispersed or encapsulated in the partially cross-linked binder resin by phase inversion emulsification granulation, it is possible to prevent mechanical stress. A particularly remarkable effect is obtained in that particles with appropriate strength that can withstand are easily obtained.

In the invention of claim 2, since the self-water-dispersible resin is used, the emulsifier or dispersion stabilizer is used.
Compared with the method of 1, the step of removing it is unnecessary, and the effect of being more excellent in productivity is further achieved.

According to the sixth aspect of the present invention, the microcapsule particles dispersed or encapsulated in the partially crosslinked binder resin using the colorant are produced by phase inversion emulsification granulation and dried to obtain a toner. The toner particles having the strength capable of withstanding the mechanical stress due to friction during mixing with the carrier or contact with the blade and the good offset resistance during fixing can be easily obtained, which is a remarkable effect.

In a seventh aspect of the present invention, the toner is obtained by producing fine capsule particles dispersed or encapsulated in a partially cross-linked self-water-dispersible binder resin using a colorant by phase inversion emulsification granulation and drying. Therefore, as compared with the method of claim 6 in which an emulsifier or dispersion stabilizer is used, there is no need for a step of removing the emulsifier and the effect of being more excellent in productivity is further exhibited.

Claims (8)

[Claims] 1. A method for producing microcapsule particles obtained by phase inversion emulsification of an organic solvent (C) solution of a binder resin (B) in which a solid substance (A) is dispersed in an aqueous medium. As the binder resin (B), a non-gel organic solvent-soluble acidic group-containing binder resin having a partially crosslinked structure is used,
And phase inversion emulsification using an organic solvent solution containing an emulsifier and / or a dispersion stabilizer, or as the binder resin (B),
A non-gelling organic solvent-soluble acidic group-containing binder resin having no crosslinking structure is used, and an amino coupling compound, an emulsifier and / or a dispersion stabilizer sufficient to form the partial crosslinking structure are used. A method for producing microcapsule particles, which comprises phase inversion emulsification using an organic solvent solution containing the same. 2. A method for producing microcapsule particles obtained by phase inversion emulsification of an organic solvent (C) solution of a binder resin (B) in which a solid substance (A) is dispersed in an aqueous medium. As the agent resin (B), phase-inversion emulsification is performed using an acidic group-containing binder resin having a partially crosslinked structure, soluble in a non-gelled organic solvent and capable of becoming self-water dispersible by neutralization, or As the binder resin (B), an acidic group-containing binder resin having no crosslinked structure, soluble in a non-gelled organic solvent and capable of becoming self-dispersible in water by neutralization is used, and the partial bridge is used. A method for producing microcapsule particles, which comprises phase inversion emulsification using an organic solvent solution containing an amino coupling compound sufficient to form a crosslinked structure. 3. The method according to claim 1 or 2, wherein the amino coupling compound is an aminosilane coupling agent. 4. The method according to claim 2, which further comprises a basic compound. 5. A binder resin particle containing a colorant, which is obtained by subjecting a solution of the binder resin (B) in which the colorant (a) is dispersed to an organic solvent (C) to phase inversion emulsification in an aqueous medium. A non-gel having a partially crosslinked structure as the binder resin (B) in a method for producing an electrophotographic toner, which is a dry toner by obtaining an aqueous dispersion of toner particles, removing the aqueous medium from the aqueous dispersion, and drying the toner. Phase-inversion emulsification using an organic solvent-soluble binder resin containing an acidic group and using an organic solvent solution containing an emulsifier and / or a dispersion stabilizer, or crosslinking as the binder resin (B). Organic using a non-gelling organic solvent-soluble acidic group-containing binder resin having no structure, and containing an amino coupling compound, an emulsifier and / or a dispersion stabilizer sufficient to form the partially crosslinked structure Invert emulsification using a solvent solution Method of manufacturing electrophotographic toner and butterflies. 6. A binder resin particle containing a colorant obtained by subjecting a solution of the binder resin (B) in which the colorant (a) is dispersed in an organic solvent (C) to phase inversion emulsification in an aqueous medium. A non-gel having a partially crosslinked structure as the binder resin (B) in a method for producing an electrophotographic toner, which is a dry toner by obtaining an aqueous dispersion of toner particles, removing the aqueous medium from the aqueous dispersion, and drying the toner. Phase-inversion emulsification using an acidic group-containing binder resin that is soluble in organic solvent and can be self-dispersible by neutralization, or does not have a crosslinked structure as the binder resin (B). , A non-gelled organic solvent-soluble, which can be self-dispersible in water by neutralization, using an acidic group-containing binder resin, and the organic solvent containing an amino coupling compound sufficient to form the partially crosslinked structure Characterized in that phase inversion emulsification is performed using a solution Method for producing a toner for electrophotography. 7. The method according to claim 6, wherein the amino coupling compound is an aminosilane coupling agent. 8. The production method according to claim 7, which further comprises a basic compound.