JP2001310904A - Aspherical polymer particle, electrophotographic toner using the same and method for producing these - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide aspherical polymer particles having functional properties such as triboelectric chargeability, fluidity and cleanability and excellent in stability and durability, to provide an electrographic toner using the same and to provide a simple production method for them. SOLUTION: Each of the aspherical polymer particles 1 has a recess 2 and a coating 4 comprising a reaction product of a di or more polybasic acid halide with at least one component selected from a di or more polyol, or di or more polyamine on the surface and is used for an electrophotographic toner. An oily phase containing a polymerizable monomer and the di or more polybasic acid halide, is dispersed in an aqueous medium containing at least one component selected from the di or more polyol or the di or more polyamine to form a suspension the dispersed phase. This suspension is held at <=50 deg.C to form the coating comprising the reation product on the surfaces of the suspended particles, and the monomer in the dispersed phase is polymerized by heating the suspension and then the particles are dried to produce the aspherical particles.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to non-spherical polymer particles obtained by suspension polymerization, an electrophotographic toner using the same, and a method for producing the same.

[0002]

2. Description of the Related Art In recent years, the importance of the particle industry utilizing the function of particles themselves has been increasing. As its application field,
Gap retaining agent, slipperiness imparting agent, carrier, standard particles, resin mechanical property improving material, resin film blocking inhibitor, paper running stabilizer, cosmetic additive, resin melting property control agent, resin Anti-shrinkage agent, toner, toner additive,
Powder coatings, optical property imparting particles and the like are known. As a method of obtaining particles having such a function, a dispersed phase composed of a polymerizable monomer composition and a continuous phase component composed of an aqueous medium are simultaneously passed through independent paths to an apparatus for applying a shearing force. The dispersion is continuously supplied, and a dispersion having droplets of a desired size is formed by applying a shearing force in the apparatus. Thereafter, the dispersion is introduced into a polymerization tank to complete the polymerization, and the polymerization is completed. A suspension polymerization method for obtaining coalesced particles is disclosed in
-43402 and Japanese Patent Application Laid-Open No. 3-56501.

[0003] By this polymerization method, a suspension polymerization technique capable of easily obtaining homogeneous particles having a desired particle size has been established. However, recently, further improvement in functionality is desired for particles obtained by the suspension polymerization method. For example, toner particles used in electronic copiers
Fluidity and triboelectricity vary depending on the shape of the particles. If the shape of the toner particles is simply spherical, it is difficult to triboelectrically charge with the carrier, it is difficult to scrape off the toner particles remaining on the photosensitive drum, and in the case of a one-component developer, it is difficult for the toner particles to adhere uniformly to the sleeve. There was a problem, and satisfactory performance was not always obtained.

[0004] Accordingly, the particles are characterized by shapes such as those having an irregular shape and those having voids therein, thereby improving the functions such as triboelectricity, fluidity and cleaning properties. There is a need for polymer particles. However, in the above-described ordinary suspension polymerization method, the shape of the obtained particles is spherical due to the influence of the surface tension of the droplet, and it has been difficult to selectively obtain non-spherical particles.

On the other hand, as a conventional method for producing particles having voids therein, there is a continuous dispersion phase composed of a polymerizable monomer composition and a liquid that is incompatible with the polymerizable monomer composition, and a continuous dispersion phase composed of an aqueous medium. The phase components are held in independent tanks,
The disperse phase and the continuous phase component are simultaneously and continuously supplied from these tanks through independent paths to a device for applying a shearing force, and have a droplet of a desired size by applying a shearing force in the device. JP-A-5-209005 proposes a method of forming a dispersion, thereafter introducing the dispersion into a polymerization tank to complete the polymerization, and drying the obtained particles.

However, when the particles having voids inside obtained by this method are used, for example, as toner for electrophotography, the durability and storage stability are not sufficient. There is a possibility that a problem that blocking occurs due to exposure to high temperature and high humidity that is crushed may occur. Further, since triboelectricity and fluidity were not sufficient, particles having more irregular shapes have been demanded. As a method of obtaining toner particles having excellent storage stability such as blocking resistance, a method of forming a film by an interfacial reaction using a polyvalent isocyanate is proposed in JP-A-8-166684.
However, since the shape of the particles produced by this method was spherical, triboelectricity and cleaning properties were not sufficient.

[0007]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide non-spherical polymer particles having functions such as triboelectrification, fluidity and cleaning properties, and having excellent storage stability and durability. An object of the present invention is to provide an electrophotographic toner having the following characteristics and a production method capable of easily producing them.

[0008]

The non-spherical polymer particles of the present invention are composed of a particle body having a depression and a film covering the surface thereof, wherein the film is a dibasic or higher polybasic acid halide, It is characterized by being formed by an interfacial reaction with at least one of polyols having a valency of at least one or polyamines having a valency of at least two. Further, when the longest diameter of the non-spherical polymer particles is A, the longest diameter of the opening of the depression is B, and the depth of the deepest part of the depression is C, the conditions of A> B, B> C, and A / 2> C are satisfied. It is desirable to satisfy The volume average particle size is
It is desirable that the thickness be 0.5 to 20 μm. Further, the electrophotographic toner of the present invention comprises a particle main body having a depression and a film covering the surface thereof, and the film is formed of a dibasic or higher polybasic acid halide, a dibasic or higher polyol or
It is characterized by being formed by an interfacial reaction with at least one of polyamines having a valency or higher. Further, the electrophotographic toner of the present invention is characterized in that 20% by weight or more of the toner particles are the non-spherical polymer particles of the present invention.

The method for producing non-spherical polymer particles according to the present invention is characterized in that a dispersion phase containing at least a polymerizable monomer and a dibasic or higher polybasic acid halide is mixed with a divalent or higher polyol or a divalent or higher polyamine. A suspension having dispersed particles of a dispersed phase is prepared by dispersing the suspension in an aqueous medium containing at least one of the above. The suspension is kept at 50 ° C. or lower, and a divalent or higher polybasic acid halide is prepared. After forming a film on the surface of the suspended particles by an interfacial reaction with at least one of divalent or higher polyol or divalent or higher polyamine, the suspension is heated to polymerize the polymerizable monomer. And drying the obtained particles.

In the method for producing non-spherical polymer particles of the present invention, the polybasic acid halide having a valency of 2 or more is contained in an amount of 0.01 to 2 parts by weight based on 100 parts by weight of the polymerizable monomer.
At least one of the polyols having a valency of at least one and the polyamines having a valency of at least 0.
It is desirable to contain it in an amount of from 01 to 2 parts by weight. Furthermore, in the method for producing non-spherical polymer particles of the present invention, the time for which the suspension is kept at 50 ° C. or lower is preferably 30 minutes or more.
The method for producing an electrophotographic toner according to the present invention may further comprise dispersing at least a polymerizable monomer, a divalent or higher polybasic acid halide and a colorant into a divalent or higher polyvalent polyol or a divalent or higher polyamine. A suspension having dispersed particles of a dispersed phase is prepared by dispersing the suspension in an aqueous medium containing at least one of the above. The suspension is kept at 50 ° C. or lower, and a divalent or higher polybasic acid halide is prepared. Divalent or higher polyol or 2
After forming a film on the surface of the suspended particles by an interfacial reaction with at least one of the polyamines having a valency of at least one, the suspension is heated to polymerize the polymerizable monomer, and the obtained particles are dried. It is characterized by making it.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail.
FIG. 1 is a schematic sectional view showing an example of the non-spherical polymer particles of the present invention. The non-spherical polymer particles 1 are particles having depressions 2, a polymer particle body 3, a divalent or higher polybasic acid halide formed on the surface thereof, and a divalent or higher polyol or a divalent or higher polyvalent acid halide. At least one of the polyamines
And a coating 4 made of a different type of reactant. The number of the depressions may be one or more. Further, the coating may cover the entirety of the particle main body 3 or may cover a part thereof.

The polymer constituting the particle body 3 is formed by polymerizing the following polymerizable monomers. That is, as the polymerizable monomer, styrene, o
-Methylstyrene, m-methylstyrene, p-methylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, 3,4-dichlorostyrene,
p-ethylstyrene, 2,4-dimethylstyrene, p-
n-butylstyrene, p-tert-butylstyrene,
Styrene such as pn-hexylstyrene, pn-octylstyrene, pn-nonylstyrene, pn-decylstyrene and derivatives thereof; ethylene-unsaturated monoolefins such as ethylene, propylene, butylene and isobutylene; Vinyl halides such as vinyl, vinylidene chloride, vinyl bromide and vinyl fluoride; organic acid vinyl esters such as vinyl acetate, vinyl propionate and vinyl benzoate; methacrylic acid, methyl methacrylate, ethyl methacrylate, methacrylic acid Methacrylic acid such as propyl, n-butyl methacrylate, n-octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, dimethylaminoethyl methacrylate, and diethylaminoethyl methacrylate; Its derivatives, acrylic acid, methyl acrylate, ethyl acrylate, n- butyl acrylate,
Isobutyl acrylate, propyl acrylate, n-octyl acrylate, dodecyl acrylate, 2-acrylate
Ethylhexyl, stearyl acrylate, acrylic acid 2
-Acrylic acid and its derivatives such as chloroethyl and phenyl acrylate; vinyl ethers such as vinyl methyl ether, vinyl ethyl ether and vinyl isobutyl ether; vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone and vinyl isopropenyl ketone; N-vinyl N-vinyl compounds such as pyrrole, N-vinylcarbazole, N-vinylindole, N-vinylpyrrolidone;
Vinyl naphthallines; acrylonitrile, methacrylonitrile, acrylamide and the like. These polymerizable monomers can be used alone or in combination of two or more depending on the purpose. In particular, when styrene or a styrene derivative among polymerizable monomers is used alone or as a polymerizable monomer by mixing with other monomers, the obtained non-spherical polymer particles have relatively good charging characteristics and resin strength. This is preferable because the developing characteristics and durability when used as an electrophotographic toner can be improved.

The film 4 is formed by reacting a divalent or higher polybasic acid halide with a divalent or higher polyol or a divalent or higher polyamine. In this case, a polyester is formed by the reaction of the dibasic or higher polybasic acid halide with the dibasic or higher polyol, and a polyamide is formed by the reaction of the dibasic or higher polybasic acid halide with the dibasic or higher polyamine. You. When the non-spherical polymer particles of the present invention are used in an electrophotographic toner, the chargeability can be controlled by adding an additive such as a charge control agent, but the charge characteristics are controlled by the film 4 formed. You can also. If the formed film 4 is mainly made of polyester and the formed film 4 is mainly made of polyamide, and if the formed film 4 is mainly made of polyamide, the chargeability is controlled according to the use of the electrophotographic toner as the positively chargeable toner. can do.

Examples of the dibasic or higher polybasic acid halide include succinic dichloride, adipic dichloride, suberic dichloride, sebacic dichloride, decanoic dichloride, dodecane diacid dichloride, eicoic diacid dichloride, isophthalic dichloride, terephthalic acid. Acid dichloride, phthalic acid dichloride and the like.

Examples of the divalent or higher polyol include ethylene glycol, diethylene glycol, propylene glycol, isopropylene glycol, octanediol,
2,2-diethyl-1,3-propanediol, spiro glycol, neopentyl glycol, 1,3-butanediol, 1,4-butanediol, 2-butyl-2-
Ethyl-1,3-propanediol, 1,6-hexanediol, hexylene glycol, 1,5-pentanediol, bis (β-hydroxyethyl) terephthalate, bis (hydroxybutyl) terephthalate, polyoxyethylenated bisphenol A, Polyoxypropylene bisphenol A, polyoxyethylenated biphenol, 1,3-cyclohexanedimethanol, 1,4-
Cyclohexanedimethanol, dihydroxycyclohexane, 1,2,6-trihydroxycyclohexane, hexanetriol, glycerin, trimethylolethane, trimethylolpropane, pentaerythritol,
Sorbitol, glycerol, 1,3,5-trihydroxymethylbenzene, bisphenol A, resorcinol, hydroquinone, catechol, pyrogallol and the like.

Examples of the diamine or higher polyamine include ethylenediamine, trimethylenediamine, tetramethylenediamine, pentamethylenediamine, hexamethylenediamine, p-phenylenediamine, m-phenylenediamine, piperazine, 2-methylpiperazine, and 2,5- Dimethylpiperazine, 2-hydroxytrimethyleneamine,
Examples thereof include diethylenetriamine, triethylenetetramine, diethylaminopropylamine, tetraethylenepentamine, and amine adducts of epoxy compounds.

An electrophotographic toner can be obtained by adding a colorant to the dispersed phase of the present invention. In this case, a dye or a pigment can be added as a coloring agent.
Examples of such coloring agents such as dyes and pigments include carbon black, iron black, rose bengal, benzidine yellow, quinacridone, rhodamine B, phthalocyanine, and mixtures thereof. The electrophotographic toner may contain additives as necessary. Examples of the additives include a fixability improver such as polyethylene and polypropylene, and a fluidity improver such as silica. .

The non-spherical polymer particles preferably have a depression satisfying the following conditions. Conditions: As shown in FIG. 1, when the longest diameter of the non-spherical polymer particles 1 is A, the longest diameter of the opening of the depression 2 is B, and the depth of the deepest part of the depression 2 is C, A> B, B > C, A / 2> C. Here, when A ≦ B, B ≦ C, or A / 2 ≦ C, when used as an electrophotographic toner, there is a possibility that a problem may occur in triboelectricity, fluidity, or cleaning properties. The longest diameter A of the non-spherical polymer particles, the longest diameter B of the opening of the dent, and the depth C of the deepest part of the dent are determined by analyzing an image of the non-spherical polymer particles by a scanning electron microscope (SEM). You can ask.

The non-spherical polymer particles preferably have a volume average particle diameter of 0.5 to 20 μm. If the volume average particle diameter is less than 0.5 μm, the cohesive force between the particles becomes large, and it becomes difficult to impart functionalities such as triboelectrification, fluidity, and cleaning properties due to the change in the shape of the dents, and 20 μm
If the particle diameter exceeds the above range, the effect of imparting functionalities such as triboelectricity, fluidity, and cleaning property may also be difficult due to a change in the shape of the depressions due to the large particle size.

Since the non-spherical polymer particles of the present invention have the above-mentioned depressions, they have functions such as triboelectrification, fluidity and cleaning properties, and prevent blocking of electrophotographic toners, slip imparting agents and films. And an optical property imparting agent. Further, a polyester, which is a reaction product of a divalent or higher polybasic acid halide and a divalent or higher polyhydric polyol, or a polyamide, which is a reaction product of a divalent or higher polybasic acid halide with a divalent or higher polyamine, on the surface of the particles Since the coating 4 is made of, there is little blocking, the strength of the particles themselves is high, and storage stability and durability are excellent.

When the non-spherical polymer particles are used as an electrophotographic toner, the content of the non-spherical polymer particles in the whole toner particles is 20% by weight or more, preferably 5% by weight.
0% by weight or more. When the content of the non-spherical polymer particles is less than 20% by weight, the effect of improving various properties such as triboelectricity, fluidity, storage stability and durability becomes insufficient.

When the non-spherical polymer particles are used as an electrophotographic toner, the non-spherical polymer particles include well-known hardly water-soluble inorganic fine particles as a dispersant, a surfactant as a dispersion stabilizing aid, and a polar monomer as a charge control agent. Alternatively, a colorant such as a polar polymer, a crosslinking agent, a wax, a magnetic powder, a fluidizing agent, and an additive may be added. By using these additives, various properties such as fluidity and chargeability of the toner for electrophotography can be further improved.

Next, the method for producing the non-spherical polymer particles of the present invention will be described. First, a dispersed phase containing at least a polymerizable monomer and a divalent or higher polybasic acid halide,
The suspension is dispersed in an aqueous medium containing at least one of a divalent or higher valent polyol or a divalent or higher polyamine to obtain a suspension having suspended particles of a dispersed phase. Next, the suspension is maintained at 50 ° C. or lower, and at least the divalent or higher polybasic acid halide and the divalent or higher polyol or divalent or higher polyamine at the interface between the suspended particles of the dispersed phase and the aqueous medium. One type is reacted to form a film of the reactant on the surface of the suspended particles. Then, after forming a film,
The suspension is heated to polymerize the polymerizable monomer in the suspended particles, thereby obtaining particles having depressions. Separating the resulting particles,
By drying, the non-spherical polymer particles of the present invention are obtained.
As means for drying, it may be dried naturally,
It may be forcibly dried with a vacuum dryer or the like.

The following are conceivable reasons why the depression is formed in the non-spherical polymer particles. Since the specific gravity of the polymerizable monomer increases during the polymerization process, the volume of the obtained polymer is smaller than the volume of the original polymerizable monomer. If a film is formed on the dispersed phase before the polymerization process, the surface area of the film does not decrease in the subsequent polymerization process, but only the volume of the polymerizable monomer inside the film decreases. The phase cannot be uniformly shrunk, and has a shape in which a part of the surface is crushed, and a depression is formed. As a method of forming a film, a method by interfacial polymerization described in JP-A-8-166684 is known. However, in the method described in JP-A-8-166684, the formation of the film and the polymerization of the polymerizable monomer are simultaneously performed, so that the dispersed phase uniformly shrinks during the polymerization process and no pit is formed. Therefore, in order to efficiently form depressions in the particles, it is necessary to maintain the suspension at 50 ° C. or lower and sufficiently form a film before the polymerization process.

The temperature of the suspension when forming the film is as follows:
It is necessary to maintain the temperature at or below the temperature at which the polymerizable monomer is polymerized, that is, at or below 50 ° C, preferably from 0 to 30 ° C.
If the temperature of the suspension exceeds 50 ° C., the polymerizable monomer is polymerized before the film is sufficiently formed, and there is a possibility that no depression is formed in the particles. While the suspension is kept at 50 ° C. or lower, the suspension may or may not be stirred. The time for holding the suspension is 30 minutes or more, preferably 60 minutes or more.
If the time to hold the suspension at 50 ° C. is less than 30 minutes,
There is a possibility that the formation of the film becomes insufficient and no dents are formed in the particles.

The addition amount of the divalent or higher polybasic acid halide in the dispersed phase is preferably 0.01 to 2 parts by weight based on 100 parts by weight of the polymerizable monomer. The amount of at least one of dihydric or higher polyol or divalent or higher polyamine in the aqueous medium may be:
It is preferably 0.01 to 2 parts by weight based on 100 parts by weight of the aqueous medium. When the addition amount of at least one of the divalent or higher polybasic acid halide, the divalent or higher polyol, or the divalent or higher polyamine is less than 0.01 part by weight,
There is a risk that the film to be formed will be thin or that no dents will be formed in the particles because some of the film is not formed. on the other hand,
If the addition amount of at least one of the divalent or higher polybasic acid halide, the divalent or higher polyol, or the divalent or higher polyamine exceeds 2 parts by weight, the production cost becomes high and the formed film is When the obtained non-spherical polymer particles are too thick and used as an electrophotographic toner, there is a possibility that a problem may occur in fixability. Further, the ratio of addition of at least one of the divalent or higher polybasic acid halide and the divalent or higher polyol or the divalent or higher polyamine may be an equimolar reaction ratio so as not to leave unreacted substances. preferable.

A polymerization initiator, the above-mentioned additives, and a diluent can be added to the dispersed phase as needed. The polymerization initiator is preferably soluble in the polymerizable monomer.
Examples of such polymerization initiators include N, N-azobisisobutyronitrile, 2,2'-azobisisobutyronitrile, 2,2'-azobis- (2,4-dimethylvaleronitrile), , 2'-Azobis-4-methoxy-2,4
-Dimethylvaleronitrile, other azo-based or diazo-based polymerization initiators; benzoyl peroxide, methyl ethyl ketone peroxide, isopropyl peroxycarbonate, and other peroxide-based polymerization initiators. When many polymerization initiators cannot be added to the dispersed phase, ammonium persulfate, potassium persulfate, or the like, or an azo-based or diazo-based water-soluble initiator may be used in combination, if necessary. It is preferable to use two or more polymerization initiators in various combinations for the purpose of controlling the molecular weight and molecular weight distribution of the finally obtained non-spherical polymer particles, or for controlling the reaction time.

The polymerization initiator is used in an amount of 0.05 to 20 parts by weight, preferably 1 to 10 parts by weight, based on 100 parts by weight of the polymerizable monomer.
It is added in parts by weight. If the amount of the polymerization initiator is less than 0.05 part by weight, the polymerization time becomes long and the molecular weight of the polymer becomes too high, which is not preferable. On the other hand, if the polymerization initiator exceeds 20 parts by weight, the molecular weight of the polymer becomes too low, which is not preferable. In order to impart blocking resistance and durability to the non-spherical polymer particles, a crosslinking agent may be further added to the dispersed phase in addition to the polymerization initiator. As the cross-linking agent, a known substance such as divinylbenzene can be exemplified.

The dispersion phase is prepared by adding a dibasic or higher polybasic acid halide, a polymerization initiator, an additive, etc. to the polymerizable monomer,
This is performed by dissolving or uniformly dispersing by stirring. If uniform dispersion is difficult, a disperser such as an ultrasonic disperser or a media disperser may be used at an appropriate stage in the process of preparing the dispersed phase.

The aqueous medium is mainly composed of water. Further, if necessary, methanol, ethanol, 2-methoxyethanol, propanol, butanol, t-butanol, benzene, toluene, xylene,
An organic solvent such as tetrahydrofuran, 2-butanone, and acetone may be added.

Further, a dispersion stabilizer, a surfactant, an emulsifier, a thickener and the like may be added to the aqueous medium. Examples of the dispersion stabilizer include organic compounds such as carboxymethyl cellulose and polyvinyl alcohol, and poorly water-soluble inorganic fine particles such as calcium sulfate and tricalcium phosphate. The addition amount of the dispersion stabilizer is preferably from 0.2 to 20% by weight, more preferably from 0.5 to 5% by weight, based on the aqueous medium. When the amount of the dispersion stabilizer added is 0.2
If the amount is less than 20% by weight, it is difficult to obtain sufficient dispersion stability of the dispersed phase, and if the amount is more than 20% by weight, it becomes difficult to remove the dispersion stabilizer from the suspended polymer particles obtained from the polymerization reaction.

The surfactant is used as an auxiliary of a dispersion stabilizer. Examples of such a surfactant include sodium dodecyl sulfonate, sodium dodecyl benzene sulfonate, and the like. As the emulsifier, for example, sodium chloride, sodium sulfate,
And neutral salts such as sodium dodecyl sulfate. The thickener prevents coalescence of the non-spherical polymer particles obtained by the polymerization reaction. Such thickeners include, for example, glycerin, ethylene glycol and the like.

Further, when water-insoluble inorganic fine particles such as tricalcium phosphate are used as the dispersion stabilizer, after the polymerization of the polymerizable monomer is completed, concentrated nitric acid, hydrochloric acid or the like is added to the aqueous medium. It is preferable to dissolve and remove poorly water-soluble inorganic fine particles adhering to the surface of the non-spherical polymer particles. When the poorly water-soluble inorganic fine particles remain on the surface of the non-spherical polymer particles,
It causes deterioration of fluidity and environmental resistance.

[0034]

Hereinafter, the present invention will be described in more detail with reference to examples. Example 1 1.0 part by weight (0.0042 mol) of sebacic acid dichloride and 4 parts by weight of N, N'-azobisisobutyronitrile were dissolved in 75 parts by weight of styrene and 25 parts by weight of 2-ethylhexyl. A dispersed phase was prepared. Next, a tricalcium phosphate slurry (trade name: TCP-10, manufactured by Taihei Chemical Industry Co., Ltd.) was added to 200 parts by weight of distilled water.
00 parts by weight was added and stirred well. Further, 0.08 part by weight of sodium dodecyl sulfate and 0.46 part by weight (0.0042 mol) of hydroquinone were dissolved to prepare an aqueous medium.

The dispersion phase is added to the aqueous medium, and HOMOMIX is added.
Using an ER (granulator manufactured by Tokushu Kika Co., Ltd.), stirring was performed for 5 minutes at a rotation speed of the turbine blades of 10,000 rpm to disperse the dispersed phase in an aqueous medium, and a suspension having suspended particles of the dispersed phase was obtained. Obtained. Next, the rotational speed of the HOMOMIXER turbine blade was reduced to 50 rpm, and the suspension was left in a constant temperature bath at 40 ° C. for 1 hour to form a film on the surface of the dispersed phase. Thereafter, the suspension was stirred at a rotation speed of 50 rpm at 60 ° C.
For 4 hours and at 90 ° C. for 4 hours to polymerize the polymerizable monomer in the dispersed phase.

After the completion of the polymerization, the mixture was cooled to room temperature, 10 parts by weight of concentrated nitric acid was added to 100 parts by weight of the aqueous medium, and the mixture was stirred at 50 rpm for 30 minutes. The product was centrifuged to remove most of the water, and then dried by a vacuum drier until the water content became 0.1% by weight or less, to obtain non-spherical polymer particles having a depression according to the present invention. FIG. 2 shows an SEM image of the obtained particles. The volume average particle diameter of the non-spherical polymer particles in this example is 7.2 μm,
The longest diameter A, the longest diameter B of the opening of the dent, and the depth C of the deepest part of the dent in the non-spherical polymer particles of FIG. 2 were as follows. A: 8.4 μm, B: 4.6 μm, C: 1.8 μm

(Example 2) Sebacic acid dichloride added to the dispersed phase was changed to 0.5 parts by weight (0.0025 mol) of terephthalic acid dichloride, and hydroquinone added to the aqueous medium was added to 1,4-butanediol 0.1%. Except having changed to 225 parts by weight (0.0025 mol), non-spherical polymer particles having depressions of the present invention were obtained in the same manner as in Example 1. FIG. 3 shows an SEM image of the obtained particles. The volume average particle diameter of the non-spherical polymer particles in this example is 7.5 μm, the longest diameter A of the non-spherical polymer particles of FIG. 3, the longest diameter B of the opening of the depression, and the depth of the deepest part of the depression. C was as follows. A: 10.2 μm, B: 5.
1 μm, C: 3.1 μm

(Example 3) The same procedure as in Example 1 was repeated except that the hydroquinone added to the aqueous medium was changed to 0.487 parts by weight (0.0042 mol) of hexamethylenediamine. Spherical polymer particles were obtained. FIG. 4 shows an SEM image of the obtained particles. The volume average particle diameter of the non-spherical polymer particles in this example is 7.1 μm, the longest diameter A of the non-spherical polymer particles in FIG. 4, the longest diameter B of the opening of the depression, and the depth of the deepest part of the depression. C was as follows. A: 8.6 μm, B: 5.6
μm, C: 1.4 μm

Example 4 0.75 parts by weight (0.005 mol) of succinic acid dichloride and 0.7% of isophthalic acid dichloride were added to the disperse phase.
The hydroquinone added to the aqueous medium was changed to 5 parts by weight (0.00375 mol), and m-phenylenediamine was added to 0.1 part by weight.
Except having changed to 94 parts by weight (0.0087 mol), non-spherical polymer particles having depressions of the present invention were obtained in the same manner as in Example 1. FIG. 5 shows an SEM image of the obtained particles.
The volume average particle diameter of the non-spherical polymer particles in this example is 8.2 μm, the longest diameter A of the non-spherical polymer particles in FIG. 5, the longest diameter B of the opening of the depression, and the depth of the deepest part of the depression. C was as follows. A: 9.3 μm, B:
7.0 μm, C: 3.5 μm

Example 5 Hydroquinone added to an aqueous medium was resorcinol 0.27 parts by weight (0.0025)
Mol), 0.15 parts by weight of tetramethylenediamine (0.
0017 mol) in the same manner as in Example 1 to obtain non-spherical polymer particles having depressions of the present invention. FIG. 6 shows an SEM image of the obtained particles. The volume average particle diameter of the non-spherical polymer particles in this example was 7.2 μm.
6, the longest diameter A of the non-spherical polymer particles, the longest diameter B of the opening of the dent, and the depth C of the deepest part of the dent were as follows. A: 9.2 μm, B: 5.1 μm, C:
1.1 μm

Comparative Example 1 Particles were obtained in the same manner as in Example 1 except that sebacic acid dichloride in the dispersed phase was not added. FIG. 7 shows an SEM image of the obtained particles. The volume average particle diameter of the particles in this comparative example is 7.3.
Spherical particles having a size of μm and having no depression were obtained.

Comparative Example 2 Particles were obtained in the same manner as in Example 1, except that hydroquinone was not added to the aqueous medium. FIG. 8 shows an SEM image of the obtained particles. The volume average particle diameter of the particles in this comparative example was 7.1 μm, and spherical particles without depressions were obtained.

Comparative Example 3 Particles were obtained in the same manner as in Example 1 except that sebacic acid dichloride in the dispersed phase and hydroquinone in the aqueous medium were not added. FIG. 9 shows an SEM image of the obtained particles. The volume average particle diameter of the particles in this comparative example was 8.2 μm, and spherical particles without depressions were obtained.

Next, each of the particles obtained in Examples 1 to 5 and Comparative Examples 1 to 3 was evaluated as follows. (1) Storage stability After leaving 10 g of the particles in an environment of 50 ° C. for 16 hours,
Table 1 shows the results of measuring the amount (% by weight) remaining on the mesh after passing through meshes of 0 mesh, 100 mesh, and 200 mesh without passing. (2) Amount of triboelectric charge The amount of triboelectric charge when particles were used as toner was measured by the following method. That is, a non-coated ferrite carrier (manufactured by Dowa Kogyo Co., Ltd., trade name: DFC-200 (type)
S)) With respect to 100 parts by weight, 5 parts by weight of each particle was mixed and stirred, and the amount of triboelectric charge was measured using a blow-off triboelectric charge measuring device manufactured by Toshiba Chemical Company. It was shown to. (3) Evaluation by Copying Machine In addition, a solid image original was copied on transfer paper using a commercially available copying machine using an agitated product (developer) of the particles and carrier used in the above-described evaluation of the triboelectric charge amount. It has been confirmed that the non-spherical polymer particles of the present invention can be copied without problems in fluidity and cleaning property to the photoreceptor.

[0045]

[Table 1]

[0046]

As described above, since the non-spherical polymer particles of the present invention have a film made of a specific reactant, they have functions such as triboelectrification, fluidity, cleaning properties, and storage stability. Excellent in properties and durability. Further, when the depression satisfies the above-mentioned conditions, it is possible to achieve both triboelectric charging, fluidity and cleaning properties. Further, when the volume average particle diameter is 0.1.
When the thickness is 5 to 20 μm, the effect of controlling the particle shape can be obtained even more. Further, the electrophotographic toner of the present invention is a toner excellent in triboelectrification, fluidity, storage stability, durability and the like, since 20% by weight or more of the toner particles are the non-spherical polymer particles of the present invention. . Further, the method for producing non-spherical polymer particles of the present invention can easily produce non-spherical polymer particles having functions such as triboelectricity, fluidity and cleaning properties at low cost, and having excellent storage stability and durability. Obtainable.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing an example of the non-spherical polymer particles of the present invention.

FIG. 2 is an SEM image of the non-spherical polymer particles of Example 1.

FIG. 3 is an SEM image of the non-spherical polymer particles of Example 2.

FIG. 4 is a SEM image of the non-spherical polymer particles of Example 3.

FIG. 5 is an SEM image of the non-spherical polymer particles of Example 4.

FIG. 6 is an SEM image of non-spherical polymer particles of Example 5.

FIG. 7 is an SEM image of a spherical particle of Comparative Example 1.

FIG. 8 is an SEM image of a spherical particle of Comparative Example 2.

FIG. 9 is an SEM image of a spherical particle of Comparative Example 3.

[Explanation of symbols]

1: non-spherical polymer particles, 2: hollow, 3: particle body, 4: coating

Continued on the front page F-term (reference) 2H005 AA01 AA13 AA15 AB06 AB07 CA04 CA08 CA09 DA05 DA07 EA10 4J011 JB08 JB18 JB21 JB26 PA88 PA96 PB08 PB40 PC07

Claims (9)

[Claims] 1. A particle body having a depression, and a coating covering the surface thereof, wherein the coating comprises at least one of a divalent or higher polybasic acid halide, a divalent or higher polyol or a divalent or higher polyamine. Non-spherical polymer particles formed by an interfacial reaction with one kind. 2. When the longest diameter of the non-spherical polymer particles is A, the longest diameter of the opening of the depression is B, and the depth of the deepest part of the depression is C, A> B, B> C, A / 2>. The non-spherical polymer particles according to claim 1, satisfying the condition of C. 3. The non-spherical polymer particles according to claim 1, wherein the volume average particle diameter is 0.5 to 20 μm. 4. A particle body having a depression, and a coating covering the surface thereof, wherein the coating is at least one of a divalent or higher polybasic acid halide, a divalent or higher polyhydric polyol, and a divalent or higher polyamine. An electrophotographic toner formed by an interfacial reaction with one type. 5. A toner for electrophotography, wherein 20% by weight or more of the toner particles are the non-spherical polymer particles according to any one of claims 1 to 3. 6. A dispersion phase containing at least a polymerizable monomer and a divalent or higher polybasic acid halide is dispersed in an aqueous medium containing at least one of a divalent or higher polyol and a divalent or higher polyamine. To prepare a suspension having suspended particles of the dispersed phase, and keeping the suspension at 50 ° C. or lower to prepare a divalent or higher polybasic acid halide and a divalent or higher polyol or a divalent or higher polyamine. After forming a film on the surface of the suspended particles by an interfacial reaction with at least one of them, the suspension is heated to polymerize the polymerizable monomer,
A method for producing non-spherical polymer particles, comprising drying the obtained particles. 7. A polybasic acid halide having a valency of 2 or more is contained in an amount of 0.01 to 2 parts by weight based on 100 parts by weight of the polymerizable monomer.
7. The composition according to claim 6, wherein at least one of the divalent or higher polyol and the divalent or higher polyamine is contained in an amount of 0.01 to 2 parts by weight per 100 parts by weight of the aqueous medium.
3. The method for producing non-spherical polymer particles according to 1.). 8. The time for keeping the suspension below 50 ° C.
The method for producing non-spherical polymer particles according to claim 6 or 7, wherein the treatment time is 30 minutes or more. 9. A dispersion phase containing at least a polymerizable monomer, a divalent or higher polybasic acid halide and a colorant, and an aqueous phase containing at least one of a divalent or higher polyhydric polyol and a divalent or higher polyamine. A suspension having suspended particles of the dispersed phase is prepared by dispersing in a medium, and the suspension is heated to 50 ° C.
After forming a film on the surface of the suspended particles by an interfacial reaction between a divalent or higher polybasic acid halide and at least one of a divalent or higher polyol or a divalent or higher polyamine, the suspension is maintained. A method for producing an electrophotographic toner, comprising heating a liquid to polymerize the polymerizable monomer and drying the obtained particles.