JPH0625309A - Resin particle having depressions and projections on their surfaces and toner for electronic photography - Google Patents

Abstract

PURPOSE:To provide the resin particles obtained by copolymerizing a monomer with a crosslinking monomer in the presence of a dispersion stabilizer under specific conditions and having depressions and projections on their surfaces, and to provide the toner produced by coloring the resin particles, improved in its cleaning property, and used for electronic photography. CONSTITUTION:When (B) a monomer (radically polymerizable vinylic unsaturated monomer) and (C) a crosslinking monomer (preferably divinyl benzene) are copolymerized in the presence of (A) a dispersion stabilizer (e.g. polyacrylic acid), B and C (suitably in a B:C=75:1 to 25:1, in which the ratio of C is larger than conventional ratios) are dissolved in a solvent dissolving B and C but not dissolving their copolymer, and A and a polymerization initiator are further added. Since projections are formed on the surfaces of the resin particles deposited at the time close to the finishing time of the polymerization when the ratio of C is large, A is further added before the formation of the depositions to produce the stable colloidal resin particles having depressions and projections on their surfaces. The toner used for electronic photography and improved in its cleaning property is obtained by coloring the resin particles on or after their polymerization.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to resin particles having surface irregularities and a toner for electrophotography.

[0002]

2. Description of the Related Art Conventional electrophotographic toners are generally manufactured by melt-kneading a thermoplastic resin, a colorant and other additives, and then pulverizing and classifying. Since such a pulverized toner has a wide particle size distribution, it is difficult to make the charging uniform, and it is difficult to obtain an image with high resolution because the particle size is large.

Therefore, the inventors of the present invention have previously proposed various methods for producing a toner using a dispersion polymerization method (Japanese Patent Laid-Open No. HEI 3).
-16863, and 3-140968).
In this method, the monomer is polymerized in a water-miscible solvent in which the monomer dissolves but the polymer does not dissolve, in the presence of a dispersion stabilizer and optionally a colorant (oil-soluble dye etc.). Is.

The electrophotographic toner obtained by such a dispersion polymerization method has the characteristics that the particle size distribution is narrow and the particle size can be reduced, and therefore, it is excellent in charging characteristics and can obtain a high quality image. There is.

[0005]

However, since the toner particles for electrophotography obtained by the dispersion polymerization method are almost spherical in shape, they have poor cleaning properties when the residual toner on the photoconductor is cleaned with a blade. There was a problem. Therefore, a main object of the present invention is to provide a resin particle which has improved cleaning property and has a small particle size and a narrow particle size distribution, which can be suitably used for an electrophotographic toner or the like.

Another object of the present invention is to provide an electrophotographic toner using the above resin particles.

[0007]

Means and Actions for Solving the Problems The resin particles of the present invention used for solving the above problems are in a solvent in which a monomer and a crosslinkable monomer are dissolved but a polymer thereof is not dissolved. In the presence of a dispersion stabilizer, it is formed by polymerizing the monomer and the crosslinkable monomer, increasing the ratio of the crosslinkable monomer, and the dispersion stabilizer By adding additional before the completion of polymerization, unevenness is formed on the surface.

As described above, according to the present invention, the unevenness is formed on the surface of the dispersed polymer particles. Therefore, when the resin particles are used for the toner, the cleaning property is greatly improved as compared with the conventional substantially spherical dispersed polymer particles. Improve to. The process of forming the resin particles of the present invention will be described with reference to FIG. First, a monomer and a crosslinkable monomer are dissolved in a predetermined solvent 1 and dispersion polymerization is performed in the presence of the dispersion stabilizer 2 ((1) in FIG. 1). The solvent dissolves the monomer and the crosslinkable monomer, but does not dissolve the polymer. Therefore, as the polymerization proceeds, the resin particles 3 start to precipitate. The resin particles 3 are dispersed in the solvent by the dispersion stabilizer 1 ((2) in FIG. 1). At this time, if the ratio of the crosslinkable monomer is large, the protrusions 4 are formed on the surface of the resin particles 5 near the end of the polymerization, but since the dispersion stabilizer 1 does not exist on the surface of the protrusions 4, it is high. Due to the cross-linking property, the resin particles 5 are aggregated with each other and precipitated, so that only resin lumps are obtained ((3) in FIG. 1).

Therefore, the dispersion stabilizer 21 is additionally added before the polymerization is completed and immediately before the protrusions 4 are formed (see FIG. 1).
(5)), the dispersion stabilizers 2 and 21 are also adsorbed on the surfaces of the protrusions 4, maintaining a stable colloidal state, and the protrusions 6
The resin particles 7 having are formed ((6) in FIG. 1). The additional addition of the dispersion stabilizer 21 is preferably performed by adding the dispersion stabilizer 21 to a predetermined solvent 11 in advance ((4) in FIG. 1).

The electrophotographic toner of the present invention contains a colorant in a solvent in which a monomer and a crosslinkable monomer are dissolved but the polymer is not dissolved in the presence of a dispersion stabilizer. Is a colored monodisperse polymer having irregularities on the surface, which is formed by polymerizing a monomer and a crosslinkable monomer as described above in a state of being dispersed or dissolved.

Another electrophotographic toner of the present invention is a spherical monodisperse polymer having irregularities on the surface, characterized in that the resin particles are colored. As described above, the electrophotographic toner of the present invention is a monodisperse type that has excellent cleaning properties and has a small particle size and a narrow particle size distribution, because the particle surface has irregularities formed thereon. Therefore, it is possible to obtain an image with high fluidity, excellent charge stability, and high resolution.

The monomer used together with the crosslinkable monomer in the present invention is a vinyl unsaturated monomer having radical polymerizability, such as monovinyl aromatic monomer, acrylic monomer and vinyl. Examples include ester-based monomers, vinyl ether-based monomers, diolefin-based monomers, mono-olefin-based monomers, halogenated olefin-based monomers and the like. As the monovinyl aromatic monomer, the following general formula (1):

[0013]

[Chemical 1] (In the formula, R ¹ is a hydrogen atom, a lower alkyl group or a halogen atom, R ² is a hydrogen atom, a lower alkyl group, a halogen atom, an alkoxy group, an amino group, a nitro group, a vinyl group, a sulfo group, a sodium sulfonate group, A monovinyl aromatic hydrocarbon represented by potassium sulfonate or a carboxyl group, for example, styrene, α-methylstyrene, vinyltoluene, α-chlorostyrene, o, m, p
-Chlorostyrene, p-ethylstyrene, sodium styrenesulfonate, divinylbenzene and the like can be mentioned.

The acrylic monomer has the following general formula
(2):

[0015]

[Chemical 2] (In the formula, R ³ represents a hydrogen atom or a lower alkyl group, R ⁴ represents a hydrogen atom, a hydrocarbon group having up to 12 carbon atoms, a hydroxyalkyl group, a vinyl ester group or an aminoalkyl group.) Monomers such as acrylic acid, methacrylic acid, methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, cyclohexyl acrylate, phenyl acrylate,
Methyl methacrylate, hexyl methacrylate, 2-ethylhexyl methacrylate, β-hydroxy acrylate, γ-hydroxy acrylate, δ-hydroxy butyl acrylate, β-hydroxy methacrylate, γ-amino acrylate, Examples include γ-N, N-diethylaminoacrylic acid propyl ester, ethylene glycol dimethacrylic acid ester, and tetraethylene glycol dimethacrylic acid ester.

The vinyl ester-based monomer is represented by the following general formula (3):

[0017]

[Chemical 3] (In the formula, R ⁵ represents a hydrogen atom or a lower alkyl group.)
Examples thereof include vinyl formate, vinyl acetate, vinyl propionate and the like. The vinyl ether-based monomer has the following general formula (4):

[0018]

[Chemical 4] (In the formula, R ⁶ represents a monovalent hydrocarbon group having up to 12 carbon atoms).
For example, vinyl methyl ether, vinyl ethyl ether,
Examples thereof include vinyl-n-butyl ether, vinyl phenyl ether and vinyl cyclohexyl ether.

The diolefin-based monomer is represented by the following general formula (5):

[0020]

[Chemical 5] (In the formula, R ⁷ , R ⁸ and R ⁹ are the same or different,
It represents a hydrogen atom, a lower alkyl group or a halogen atom. Examples of the diolefin-based monomer include butadiene, isoprene, and chloroprene.

As the mono-olefin type monomer, the following general formula (6):

[0022]

[Chemical 6] (In the formula, R ¹⁰ and R ¹¹ are the same or different and each represents a hydrogen atom or a lower alkyl group.) A monoolefin monomer represented by, for example, ethylene, propylene,
Butene-1, pentene-1, 4-methylpentene-1 and the like can be mentioned.

As the halogenated olefin-based monomer,
Examples thereof include vinyl chloride and vinylidene chloride.
Each of the above monomers can be used alone or in combination of two or more. Among the above monomers, the monomers preferably used in the present invention are styrene and (meth)
Examples thereof include acrylic acid esters and a combination system of styrene and (meth) acrylic acid ester.

Examples of the crosslinkable monomer in the present invention include polyvinyl monomers such as divinylbenzene, diallyl phthalate and tricyanurate. Among these, it is particularly preferable to use divinylbenzene. The weight ratio of the blended monomer to the crosslinkable monomer is preferably about 75: 1 to 25: 1 in order to form the protrusions 4 on the surface of the resin particles to be formed. When the ratio of the crosslinkable monomer is lower than the above range, resin particles having sufficient unevenness to improve the cleaning property cannot be obtained, and when the ratio of the crosslinkable monomer is higher than the above range. Is not preferable because resin particles are not formed and aggregates are formed. By the way, in the case of obtaining spherical resin particles having no protrusions 4, the ratio of the above monomer to the crosslinkable monomer is
Usually, it is about 200: 0 to 200: 1.

To prepare dispersion-polymerized particles using these monomers, the monomer and the crosslinkable monomer are dissolved in a solvent in which the monomer and the crosslinkable monomer are dissolved but the polymer is not dissolved. Body, further dissolve the dispersion stabilizer and the polymerizable initiator,
The polymerization reaction is carried out by heating under stirring. As the solvent, various solvents can be used depending on the types of monomers and crosslinkable monomers used, and examples thereof include water; lower alcohols such as methyl alcohol, ethyl alcohol and isopropyl alcohol; ethylene glycol. , Polypropylene alcohols such as propylene glycol, butanediol, diethylene glycol, and triethylene glycol; cellosolves such as methyl cellosolve and ethyl cellosolve; ketones such as acetone and methyl ethyl ketone; ethers such as tetrahydrofuran; esters such as ethyl acetate. can give.

These solvents can be used alone or in combination of two or more kinds. Solvents preferably used in the present invention, lower alcohols such as ethanol,
Examples thereof include water or a mixed solvent of water and a lower alcohol. In the above mixed solvent, the weight ratio of water to lower alcohol is 40:60 to 5:95, and particularly 30:70 to 1
It is preferably within the range of 0:90. The amount of the solvent used is 50 to 500 per 100 parts by weight of the first monomer.
It is preferably in the range of 0 parts by weight, particularly 500 to 2500 parts by weight.

The solvent used for polymerization and the solvent for additional addition are preferably the same, but different solvents may be used as long as they are compatible. Examples of the dispersion stabilizer for stabilizing the dispersibility of the polymer in the solvent include polyacrylic acid, polyacrylic acid salt, polymethacrylic acid, polymethacrylic acid salt, and (meth) acrylic acid- (meth) acrylic acid ester copolymer. Polymer, acrylic acid-vinyl ether copolymer, methacrylic acid-styrene copolymer, carboxymethyl cellulose, poly (hydroxystearic acid-
Examples thereof include g-methyl methacrylate-co-methacrylic acid) copolymer, polyethylene oxide, polyacrylamide, methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, polyvinyl alcohol and the like. Further, nonionic surfactants, anionic surfactants, cationic surfactants, amphoteric surfactants and the like can also be used. The amount of such dispersion stabilizer used is in the range of 0.1 to 30% by weight, preferably 1 to 10% by weight, based on the total amount of the monomer and the crosslinkable monomer.

The dispersion stabilizer used for the polymerization and the dispersion stabilizer for additional addition may be the same or different dispersion stabilizers may be used. As the polymerization initiator,
Those which are insoluble in water and compatible with both the monomer and the crosslinkable monomer are preferable, for example, azo compounds such as azobisisobutyronitrile; cumene hydroperoxide,
t-butyl hydroperoxide, dicumyl peroxide, di-t-butyl peroxide, benzoyl peroxide,
In addition to peroxides such as lauroyl peroxide, conventionally known photopolymerization initiators can be used when the polymerization is carried out by irradiation with ultraviolet rays or visible rays. The amount of the polymerization initiator used is 0.001 to 10% by weight, preferably 0.01 to 0.5, based on the total amount of the monomer and the crosslinkable monomer.
It is in the range of% by weight. It is also possible to initiate the polymerization using γ-rays, accelerated electron beams, etc. In this case, it is not necessary to use a polymerization initiator. Further, the polymerization may be initiated by combining ultraviolet rays and various photosensitizers.

If necessary, in addition to the above components, a charge control agent, an offset preventive agent (release agent), etc. may be added. The charge control agent is blended when the toner is used in a two-component developer, and is an oil-soluble dye such as nigrosine base (CI5045), oil black (CI26150) and spirone black; metal naphthenate, fat Examples include metal soap and resin acid soap.

Examples of the anti-offset agent include low molecular weight polyethylene, low molecular weight polypropylene, various waxes, and silicone oil. The reaction liquid containing each of the above components is polymerized at a temperature of -30 to 90 ° C, particularly 30 to 80 ° C with stirring for 0.1 to 50 hours. At this time, it is preferable to replace the inside of the reaction system with an inert gas in order to suppress the termination reaction of the polymerization due to oxygen.

Further, the time of additional addition of the dispersion stabilizer is before the completion of the polymerization and before the formation of the protrusions, and the time from the initiation of the polymerization to the aggregation of the polymerization system is previously investigated by a preliminary experiment. It is preferable to add a dispersion stabilizer just before aggregation starts. Specifically, it is usually preferable to additionally add the dispersion stabilizer about 2 to 8 hours after the initiation of the polymerization. If the time of additional addition is earlier than this, the protrusions will not grow sufficiently, and if it is later than this, protrusions on which the dispersion stabilizer is not adsorbed will grow and the resin particles will aggregate.

After the additional addition, the reaction is further continued to precipitate the produced resin particles. When the obtained resin particles are used as a toner, it is preferable that the volume average particle diameter thereof is usually 4 to 8 μm, particularly 5 to 8 μm in order to obtain a high resolution image. The resin particles having irregularities on the surface of the present invention can be used not only as the toner for electrophotography described above but also as a filler for paints, cosmetics, etc., as a spacer for liquid crystals, etc.

In order to color the resin particles in order to obtain the toner, a colorant such as a dye is dissolved or dispersed in the reaction liquid for producing the dispersed polymer particles, and the monomer and the crosslinkable monomer are polymerized. Accordingly, there are a method of coloring by incorporating a dye into the resin particles and a method of coloring the resin particles after polymerization. As the colorant used in the former method, a dye that is better dissolved in the monomer than the solvent, particularly an oil-soluble dye, is preferably used. The oil-soluble dye mainly transfers to the polymer rather than to the solvent when the amount of the monomer decreases due to the progress of polymerization, so that efficient dyeing can be performed. Specific examples of oil-soluble dyes are shown below. Black dye Black FS-Special A, Black S, Black #
103, Black # 107, Black # 215, Black # 141 (all are trade names manufactured by Chuo Gosei Kagaku KK), OPLAS Black HZ, Oplas Black # 83
6, Oplas Black # 838 (all are trade names manufactured by Orient Chemical Industry Co., Ltd.). Red dye Macrolex (MACROLEX) Red 5B, Macrolex Red Violet R (all are trade names manufactured by Bayer), Sumiplast (AS), Sumiplast Red B-2, Samiplast Red HLG-Z
(All are trade names manufactured by Sumitomo Chemical Co., Ltd.), Oprah Red RR, Oprah Red # 330 (all are trade names manufactured by Orient Chemical Co., Ltd.), Red 6B, Red TR-71
(All are trade names of Chuo Gosei Kagaku). Orange dyes Macrolex Orange 3G, Macrolex Orange R (all are trade names manufactured by Bayer), Orange S, Orange R, orange # 826N (all are trade names manufactured by Chuo Gosei Kagaku), Oplus Orange PS, Oh Plus Orange RR (all are trade names manufactured by Orient Chemical Industry Co., Ltd.), Samiplast Orange HRP (trade name manufactured by Sumitomo Chemical Co., Ltd.). Yellow dyes Macrolex Yellow 6G, Macrolex Yellow R (all are trade names manufactured by Bayer), Yellow D, Yellow GE, Yellow # 189 (all are trade names manufactured by Chuo Synthetic Chemicals), Samiplast Yellow GC, Sami Plast Yellow R (all are trade names manufactured by Sumitomo Chemical Co., Ltd.), Oplus Yellow 3G, Oplus Yellow # 130 (all are trade names manufactured by Orient Chemical Co., Ltd.). Purple dye Macrolex Violet 3R, Macrolex Violet B (all are trade names manufactured by Bayer), Violet MVB (trade name by Chuo Gosei Kagaku), Samiplast Violet RR, Samiplast Violet B (all are Sumitomo Chemical Co., Ltd. Company name), Oplus Violet # 370, Oplus Violet # 732 (all are trade names of Orient Chemical Industry Co., Ltd.). Blue dye Macrolex Blue RR (Bayer brand name),
Blue BO, Blue # 8B (all are trade names manufactured by Chuo Gosei Kagaku), Samiplast Blue OR, Samiplast Blue GP, Samiplast Blue S (all are trade names manufactured by Sumitomo Chemical Co., Ltd.), Oplus Blue IIN , Oplas Blue # 630 (all are trade names manufactured by Orient Chemical Industry Co., Ltd.). Green dye Macrolex Green 5B, Macrolex Green G (all are trade names manufactured by Bayer), Green # 55
0, Green # 201 (all are trade names of Chuo Gosei Kagaku), Samiplast Green G (trade name of Sumitomo Chemical Co., Ltd.), Oplus Green # 502, Oplus Green # 503 (all are Orient Chemical Co., Ltd.) Product name made by the company). Brown dyes Brown PB, Brown SG (all are trade names manufactured by Chuo Synthetic Chemical Industry Co., Ltd.), Oplus Brown # 430, Oplas Brown # 431 (all trade names manufactured by Orient Chemical Industry Co., Ltd.).

The amount of the oil-soluble dye used varies depending on the desired degree of color density, but is usually 1 to 10 ^-9 times, especially 10 ^-6 times the weight of the reaction solution 1. It is preferable. On the other hand, the latter method of coloring resin particles with a dye is carried out, for example, by dispersing the resin particles together with a dye such as a dispersible dye in an aqueous medium, and stirring at a predetermined temperature for a predetermined time.

The temperature at the time of dyeing is not particularly limited, but it is preferably within the range of the glass transition temperature of the polymer constituting the resin particles or the glass transition temperature + 40 ° C. If the temperature is lower than the glass transition temperature of the polymer constituting the resin particles, it may not be dyeable to a desired coloring density, or it may take a long time to dye the glass transition temperature +4.
If the temperature is higher than 0 ° C, the resin particles may be fused to form a lump.

Examples of dispersible dyes used for dyeing include azo dyes, anthraquinone dyes, indigoid dyes, sulfur dyes and phthalocyanine dyes. The dispersible dye preferably has a high affinity for the polymer forming the resin particles and can dye the resin particles firmly. The amount of the dispersible dye used varies depending on the degree of the desired coloring density, but usually, for resin particles,
It is preferably at least 2% by weight, particularly preferably at least 4% by weight. Water is usually used as the aqueous medium, but when the dispersibility of the resin particles and the dye is poor, a small amount of a suitable organic solvent may be added. The amount of the aqueous medium used is preferably 500 parts by weight or more based on 100 parts by weight of the resin particles.

[0037]

EXAMPLES Next, the resin particles and the electrophotographic toner of the present invention will be described in more detail with reference to examples. Example 1 (1) Synthesis of resin particles having irregularities on the surface In a 1-liter separable flask, 400 g of isopropyl alcohol, 100 g of water, 180 g of styrene, 2-
Charge 20 g of ethylhexyl methacrylate, 0.1 g of sodium styrenesulfonate, 2 g of polymethacrylic acid, 2.5 g of divinylbenzene and 5 g of 2,2'-azobisisobutyronitrile, and stir speed 40 under nitrogen stream.
Polymerization was initiated at 70 ° C. with stirring at rpm. After 6 hours, 200 g of a 1.25% by weight polyacrylic acid solution in isopropyl alcohol was added. Further, polymerization was carried out at the same stirring speed and temperature for 10 hours, filtered, washed and dried to obtain a white powder.

When the particles were observed with an electron microscope,
Resin particles having irregularities on the surface and having a uniform particle size were generated. An electron micrograph of the particles is shown in FIG. The particle size distribution of these particles is shown in FIG. (2) Dyeing of resin particles 100 g of resin particles obtained in (1) above, 10 g of disperse dye
And 0.2 g of sodium dodecyl sulfate were dispersed in 1 liter of water, charged into an autoclave, and heated at 120 ° C. Stained for hours. After dyeing, it was filtered and dried to obtain a black toner. No change was observed in the unevenness of the particle surface after dyeing. (3) Evaluation of Cleaning Property The cleaning property of the black toner obtained in (2) above was evaluated by the following method.

(Evaluation method) Electrophotographic copying machine DC-120
5 (A4 machine manufactured by Mita Industry Co., Ltd.) was used as an evaluation machine. When a 30 mm Munsell N2.0 strip is pasted on an A4 size blank sheet as shown in FIG. 4 to make an original and a paperless copy is performed, the toner is developed in a strip shape in the center of the photosensitive drum in the longitudinal direction. DC-1 before the cleaning process is completed
When the power switch of 205 is turned off and the photoconductor drum is taken out, if it is completely cleaned, there is no toner in the portion where the cleaning process is completed. If the toner is not completely cleaned, the toner remains on the developed portion. Adhere the cellophane adhesive tape sufficiently to the remaining portion, peel it off, attach the tape to the paper as it is, and use the image densitometer to measure the image density (I.
D) was measured.

Generally, according to this method, the image density is 0.10 to 0.14 when there is no toner on the drum, whereas when the toner remains, it depends on the toner amount. It is 0.2 to 1.4. (Evaluation Results) The black toner obtained in (2) above was mixed with a ferrite carrier so that the toner concentration was 3% by weight to prepare a developer. When the cleaning property of this developer was evaluated according to the above-mentioned evaluation method, the measured value was 0.122, which was almost the same as the value when no toner remained on the drum. By the way, this developer was added to the DC
When the Munsell N2.0 original was mounted on a -1205 and copied, the density of the copied image was about 0.8. Example 2 (1) Synthesis of resin particles having irregularities on the surface Heptane 200 was placed in a 1 liter separable flask.
g, methyl methacrylate 45 g, butyl acrylate 15
g, 2-ethylene glycol dimethacrylate 5 g, sodium styrenesulfonate 0.02 g, polybutadiene 0.6 g, and azobisisobutyronitrile 0.0
2 g was charged, and polymerization was started at 70 ° C. under a nitrogen stream while stirring at a stirring speed of 40 rpm. After 6 hours, 200 g of a 1.25 wt% polybutadiene heptane solution was added. Further, polymerization was carried out at the same stirring speed and temperature for 10 hours, filtered, washed and dried to obtain a white powder.

When the particles were observed with an electron microscope,
Resin particles having irregularities on the surface and having a uniform particle size were generated. An electron micrograph of the particles is shown in FIG. (2) Coloring of resin particles The resin particles obtained in (1) above were dyed in the same manner as in Example 1 to obtain a black toner. (3) Evaluation of Cleaning Property The cleaning property of the toner obtained in (2) above was evaluated in the same manner as in Example 1. As a result, the measured value was 0.123, which was almost the same as the value when there was no toner on the drum. On the other hand, when this developer was mounted on DC-1205 and a document of Munsell N2.0 was copied, the density of the copied image was about 1.3. Comparative Example 1 (1) Synthesis of resin particles In a 1 liter separable flask, 400 g of isopropyl alcohol, 100 g of water, 180 g of styrene, 2-
Charge 20 g of ethylhexyl methacrylate, 0.1 g of sodium styrenesulfonate, 2 g of polymethacrylic acid, 2.0 g of divinylbenzene and 5 g of 2,2'-azobisisobutyronitrile, and stir speed 40 under nitrogen stream.
Polymerization was carried out at 70 ° C. for 8 hours while stirring at rpm.
When the obtained resin particles were observed with an electron microscope, they were spherical and had uniform particle diameters. An electron micrograph of the particles is shown in FIG. (2) Coloring of resin particles The resin particles obtained in (1) above were dyed in the same manner as in Example 1 to obtain a black toner. (3) Evaluation of Cleaning Property The cleaning property of the toner obtained in (2) above was evaluated in the same manner as in Example 1. As a result, the measured value was 0.586, and the cleaning property was very poor. Comparative Example 2 (1) Synthesis of Resin Particles Resin particles were prepared in the same manner as in Example 1 except that the polymerization was started under the same conditions as in Example 1 and the isopropyl alcohol solution of polyacrylic acid was added 4 hours after the start of polymerization. Got When the resin particles were observed with an electron microscope, they remained almost spherical. An electron micrograph of these particles is shown in FIG.
Shown in. This is because the isopropyl alcohol solution of polyacrylic acid was introduced earlier than in Example 1, so that the dispersion stabilizer was adsorbed to the protrusions before the protrusions on the particle surface were sufficiently grown, and It is presumed that the intensive monomer absorption of was blocked. . (2) Coloring of resin particles The resin particles obtained in (1) above were dyed in the same manner as in Example 1 to obtain a black toner. (3) Evaluation of Cleaning Property The cleaning property of the toner obtained in (2) above was evaluated in the same manner as in Example 1. As a result, the measured value was 0.620, and the cleaning property was very poor. Comparative Example 3 (1) Synthesis of Resin Particles Polymerization was started under the same conditions as in Example 1, and a solution of polyacrylic acid in isopropyl alcohol was added 7 hours after the start of polymerization. Began to agglomerate, and almost all particles agglomerated in 8 hours. Polymerization was continued in the agglomerated state, and filtration, washing and drying were performed, but resin particles having a particle size usable as a toner were not obtained. An electron micrograph of this aggregate is shown in FIG. Comparative Example 4 (1) Synthesis of Resin Particles In Example 1, 200 g of a 1.25 wt% isopropyl alcohol solution of polyacrylic acid was charged in advance in the polymerization initiator, and the same stirring speed as in Example 1 was used.
Polymerization was carried out at 70 ° C. for 16 hours while stirring at rpm.
When the resin particles were observed with an electron microscope, they remained almost spherical. An electron micrograph of the particles is shown in FIG. Examples 3 to 5 The compounds shown in Table 1 and Table 2 were used as the monomer, the crosslinkable monomer, the dispersion stabilizer at the initial stage of polymerization, and the dispersion stabilizer for additional addition, respectively, under the conditions shown in the same table. Resin particles were obtained in the same manner as in Example 1 except that the polymerization was performed. Irregularities were formed on all the obtained resin particles. Each resin particle was treated in the same manner as in Example 1 to obtain a black toner, and its cleaning property was evaluated. The results are also shown in Table 2.

[0042]

[Table 1]

[0043]

[Table 2]

[0044]

INDUSTRIAL APPLICABILITY The resin particles of the present invention are dispersed on the surface of the dispersion-polymerized particles by increasing the ratio of the crosslinkable monomer in the dispersion polymerization method and additionally adding the dispersion stabilizer before the completion of the polymerization. Since the protrusions are formed, there is an effect that it can be suitably used as a toner having unevenness on the surface. The resin particles of the present invention can also be used as a filler for paints, cosmetics and the like.

Since the electrophotographic toner of the present invention obtained by coloring the above resin particles has irregularities on the surface,
As compared with the conventional dispersion-polymerized toner having a substantially spherical shape, the cleaning property by the blade is improved.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a concavo-convex forming process in the present invention.

FIG. 2 is a scanning electron micrograph showing the particle structure of resin particles having irregularities on the surface obtained in Example 1 of the present invention.

FIG. 3 is a graph showing a particle size distribution of resin particles obtained in Example 1 of the present invention.

FIG. 4 is a diagram for evaluating cleaning properties in Examples.
It is a top view which shows the original which stuck the strip of 30 mm Munsell N2.0 on the white paper of A4 size.

FIG. 5 is a scanning electron micrograph showing the particle structure of resin particles having irregularities on the surface obtained in Example 2 of the present invention.

6 is a scanning electron micrograph showing the particle structure of resin particles obtained in Comparative Example 1. FIG.

7 is a scanning electron micrograph showing the particle structure of resin particles obtained in Comparative Example 2. FIG.

FIG. 8 is a scanning electron micrograph showing the particle structure of the aggregated resin obtained in Comparative Example 3.

9 is a scanning electron micrograph showing the particle structure of resin particles obtained in Comparative Example 4. FIG.

[Drawing reference number]

 DESCRIPTION OF SYMBOLS 1 Solvent 2 Dispersion stabilizer 3 Resin particle 4 Protrusion 5 Resin particle 6 Protrusion 7 Resin particle 11 Solvent 21 Dispersion stabilizer

Claims (4)

[Claims] 1. A monomer and a crosslinkable monomer are dissolved,
The polymer is a resin particle formed by polymerizing the monomer and the crosslinkable monomer in the presence of a dispersion stabilizer in a solvent that does not dissolve, the ratio of the crosslinkable monomer being Resin particles characterized in that unevenness is formed on the surface by increasing the amount and additionally adding the dispersion stabilizer before the completion of polymerization. 2. The resin particles according to claim 1, wherein the crosslinkable monomer is divinylbenzene. 3. The monomer and the crosslinkable monomer dissolve,
The polymer is formed by polymerizing the monomer and the crosslinkable monomer in a solvent that does not dissolve, in the presence of a dispersion stabilizer, and in a state in which the colorant is dispersed or dissolved in the solvent. An electrophotographic toner, characterized in that unevenness is formed on the surface by increasing the ratio of the crosslinkable monomer, and by additionally adding the dispersion stabilizer before the completion of polymerization, Electrophotographic toner which is a prepared monodisperse polymer. 4. A toner for electrophotography, which is obtained by coloring the resin particles according to claim 1 and which is a monodisperse polymer having irregularities on the surface.