JP2007279328A - Method for manufacturing suspension polymerization toner particle and toner particle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide suspension polymerization toner particles excellent in storage stability and fluidity useful for electrophotography, electrostatic recording, electrostatic printing or the like. <P>SOLUTION: The method for manufacturing suspension polymerization toner particles comprises polymerizing polymerizable monomers for formation of toner particles in a dispersion medium includes polymerizing a mixture of the polymerizable monomer with resin fine particles or mixing and polymerizing the polymerizable monomer which is partially polymerized and resin fine particles. The toner particles are obtained by the above method. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for producing toner particles and toner particles. More specifically, the present invention relates to a method for producing suspension polymerized toner particles having excellent storage stability and fluidity useful for electrophotography, electrostatic recording, electrostatic printing and the like, and suspension polymerized toner particles obtained by the production method.

In recent years, in image forming technologies such as electrophotography and electrostatic recording, technologies for forming full-color images using four-color toners of black, yellow, magenta, and cyan have been rapidly developed. In addition, various full-color image forming apparatuses using such a technique have been widely used. With the widespread use of such devices, there is a need for further image quality improvement and print quality improvement.
Conventional toner used to form full-color images is manufactured by crushing and classifying a composition obtained by melt-mixing a colorant, charge control agent, release agent, etc. in a thermoplastic resin and uniformly dispersing it. Has been. Such a method is called a pulverization method, and has a feature that management of materials and processes is relatively easy. As another method, a method for producing toner by a suspension polymerization method has been proposed. This method requires a binder resin, a colorant such as a dye or pigment, and a substance to be included in the toner, such as a magnetic material, carbon black, a charge control agent, a release agent such as wax or silicone oil, and the like. Depending on the conditions, the polymer composition is dissolved or dispersed in a polymerizable monomer together with a polymerization initiator and a dispersant to obtain a polymerizable composition, which is dispersed in an aqueous phase containing a dispersion stabilizer by using a dispersing device. Then, the dispersion is polymerized and solidified to obtain polymer particles (toner particles) having a desired particle size and composition.
Since this method does not have a pulverization step as in the conventional pulverization method, the effects of energy saving, improvement in process yield, and cost reduction are expected.
In addition, there is a demand for a toner that can be fixed at a lower temperature from the viewpoint of increasing the image forming speed, saving energy, and reducing the size of a copying machine or the like. In particular, in full-color copying machines and full-color printers, the glossiness and color mixing properties of the image are required, so that the toner is required to have a lower melt viscosity. However, when the melt viscosity of the resin is lowered, the glass transition temperature (hereinafter also referred to as Tg) is lowered at the same time, so that the toner aggregates during storage and at the atmospheric temperature in an apparatus such as a copying machine, and the heat resistance stability. There was a problem of worsening the fluidity.

  On the other hand, in recent years, there has been a strong demand for reducing the toner particle size in order to improve the image quality and resolution of full-color images. However, since the toner by the conventional pulverization method has an irregular shape, the powder fluidity becomes insufficient when the particle size is reduced, and it becomes difficult to supply the toner to the developing device, and the transfer property is also low. The problem of getting worse arises. Furthermore, because of the irregular shape, a problem arises in that the fine particles generated by crushing some of the toner particles contaminate the surface of the carrier due to the shearing force generated by stirring in the developing box, which adversely affects the charging of the toner. It is known.

On the other hand, as pressure toners and low-temperature fixing toners, toners having a capsule structure (core-shell structure) have been proposed (Patent Documents 2, 4, 5, etc.). Since the toner having a capsule structure is generally manufactured by a wet method, the shape is spherical, and a release agent or the like can be included in the toner. It is desirable that the toner having this capsule structure has an irregular shape. Therefore, it is feasible and effective by encapsulating the spherical core with a capsule whose surface shape has irregularities. For this purpose, several methods have already been proposed (Patent Documents 1, 3, etc.). However, the performance cannot always be improved simply by using a core-shell structure for the toner.
JP 2005-274964 A Japanese Patent Laying-Open No. 2005-099079 Japanese Patent Laying-Open No. 2005-091436 JP 2002-229251 A JP 2002-229248 A

  The object of the present invention is to solve the above-mentioned problems of conventional toners, and to provide a suspension-polymerized toner capable of obtaining a toner having excellent low-temperature fixability and storage stability, as well as excellent powder flowability and durability. The object is to provide a method for producing particles.

As a result of intensive studies to achieve the above-mentioned object, the present inventors have conducted polymerization by mixing resin fine particles with a polymerizable monomer before the start of suspension polymerization, or the polymerizable monomer. By mixing and polymerizing a part of the polymer in a polymerized state, resin fine particles adhere to the toner particle surface, thereby improving fluidity and storage stability without impairing low-temperature fixability. And completed the present invention.
That is, the present invention provides the following (1) to (7).
(1) In producing a suspension polymerized toner particle by polymerizing a polymerizable monomer for toner particle formation in a dispersion medium, a mixture of the polymerizable monomer and resin fine particles is polymerized, or A method of producing suspension-polymerized toner particles, wherein polymerization is performed by mixing the polymerizable monomer and resin fine particles in a state in which a part is polymerized,
(2) The method for producing suspension-polymerized toner particles according to (1), wherein the resin fine particles have a glass transition temperature of 80 to 150 ° C. and a particle diameter of 50 to 500 nm.
(3) The method for producing suspension-polymerized toner particles according to (1) or (2), wherein the resin fine particles are resin fine particles dissolved in the polymerizable monomer,
(4) The suspension polymerized toner particles according to any one of (1) to (3), wherein the resin fine particles are mixed within a range where the polymerization rate of the polymerizable monomer is greater than 0 and 40% or less. Method,
(5) The method for producing suspension-polymerized toner particles according to any one of (1) to (4), wherein the resin fine particles are styrene resin, acrylic resin, or styrene-acrylic resin,
(6) The method for producing suspension-polymerized toner particles according to any one of (1) to (5) above, wherein the resin fine particles are a resin modified with a functional group-containing compound, and (7) (1) to (1) above. The suspension-polymerized toner particles obtained by the production method according to any one of (6) are provided.

  According to the present invention, toner particles having excellent storage stability and fluidity can be provided without impairing low-temperature fixability useful for electrophotography, electrostatic recording, electrostatic printing, and the like. By using the toner particles, it is possible to form a full-color toner image excellent in fixing characteristics without fogging and filming.

Hereinafter, the present invention will be described in detail.
In the present invention, the polymerizable monomers used in the method for producing toner particles are addition polymerization and condensation polymerization monomers. Preferably, it is an addition polymerization monomer.

Examples of addition polymerization monomers include styrene, α-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, 3,4- Dichlorostyrene, p-ethylstyrene, 2,4-dimethylstyrene, pn-butylstyrene, p-tert-butylstyrene, pn-hexylstyrene, pn-octylstyrene, pn-nonylstyrene Styrene derivatives such as ethylene, propylene, butylene, and isobutylene; unsaturated polyenes such as butadiene and isoprene; vinyl chloride, chloride Vinyl halides such as vinylidene, vinyl bromide, vinyl iodide; vinyl acetate, vinyl propionate, Vinyl esters such as vinyl benzoate; methyl methacrylate, ethyl methacrylate, propyl methacrylate, -n-octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, dimethyl methacrylate Methacrylic acid esters such as aminoethyl, diethylaminomethyl methacrylate; methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate, propyl acrylate, n-octyl acrylate, dodecyl acrylate, Acrylic esters such as 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, phenyl acrylate; vinyl methyl ether, vinyl ethyl ether, vinyl isobutyether Vinyl ethers such as; vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone, and methyl isopropenyl ketone; N-vinyl compounds such as N-vinyl pyrrole, N-vinyl carbazole, N-vinyl indole, and N-vinyl pyrrolidone; Vinyl naphthalenes; nitriles such as acrylonitrile and methacrylonitrile can be listed.

The said polymerizable monomer may be used independently and may use 2 or more types together.

When the polymerizable monomer is mixed with the resin fine particles described later, it is preferably dispersed or suspended in a dispersion medium. Water is used as the dispersion medium.

  Next, resin fine particles used in the method for producing suspension polymerization toner particles of the present invention will be described. The resin fine particles are preferably made of a styrene resin, an acrylic resin and / or a styrene-acrylic copolymer. Other resins are less likely to adhere to the surface of the toner particles even if added immediately after the start of polymerization, and the effect of improving the fluidity and storage stability of the toner particles cannot be expected.

  The particle diameter of the resin fine particles is preferably 50 to 500 nm, and more preferably 100 to 400 nm. When the thickness is 50 nm or more, the particles can be stably produced. When the thickness is 500 nm or less, the resin fine particles and the toner particles are easily attached, and the fluidity of the toner particles is prevented from being lowered. The characteristics can be prevented from being adversely affected.

  The glass transition temperature of the resin fine particles is preferably 80 to 150 ° C, and more preferably 100 to 130 ° C. By setting the temperature to 80 ° C. or higher, the effect of improving the storage stability of the toner particles is shown. By setting the temperature to 150 ° C. or lower, it is possible to prevent the toner fixing characteristics from being adversely affected.

  When the resin fine particles are mixed with the polymerizable monomer, it is usually preferable to mix them in the state of a dispersion prepared by dispersing the resin fine particles in water. When the resin fine particles are dispersed in water, the mass ratio of the resin fine particles / water is preferably in the range of 1/100 to 1/5, more preferably 1/20 to 1/10. By mixing and dispersing both at such a mass ratio, the adhesion of the resin fine particles to the toner particle surface becomes good.

Further, the resin fine particles used may be subjected to a modification treatment with a functional group-containing compound. Specifically, it is modified by introducing a monomer unit having an amino group-containing ethylenically unsaturated bond into the resin particles using, for example, dimethylaminoethyl (meth) acrylate.
By modifying the resin fine particles with the functional group-containing compound, resin fine particles having the same function as the charge control agent described later can be obtained. In this case, the charging characteristics of the toner particles can be improved. .

  The mixing ratio of the resin fine particles and the polymerizable monomer is usually about 0.1 to 20 parts by mass, preferably 1 to 5 parts by mass with respect to 100 parts by mass of the polymerizable monomer. By setting it to 0.1 parts by mass or more, fluidity and storage stability are improved, and by setting it to 20 parts by mass or less, it is possible to prevent deterioration of the fixing characteristics of the toner particles.

The mixing of the polymerizable monomer and the resin fine particles is preferably performed when the polymerization rate of the polymerizable monomer is 0 to 40%. By mixing when the polymerization rate is 40% or less, the resin fine particles easily adhere to the surface of the toner particles, and the storage stability of the toner particles is improved. Further, it is possible to prevent unnecessary resin fine particles from being mixed in the toner particles and to prevent the image characteristics from being adversely affected.

When carrying out suspension polymerization of the polymerizable monomer, a polymerization initiator is used. Various known polymerization initiators can be used as long as they do not adversely affect the coloring degree of the toner particles. Examples of the polymerization initiator include 2,2'-azobisisobutyronitrile, 2,2'-azobis- (2,4-dimethylvaleronitrile), 2,2'-azobis- (2-methylbutyro). Nitrile), 1,1'-azobis- (cyclohexane-1-carbonitrile), dimethyl-2,2'-azobisisobutyrate, 4,4'-azobis-4-cyanovaleric acid, 2,2'-azobis -Azo compounds such as (4-methoxy-2,4-dimethylvaleronitrile), benzoyl peroxide, methyl ethyl ketone peroxide, diisopropyl peroxycarbonate, cumene hydroperoxide, t-butyl hydroperoxide, di-t- Butyl peroxide, dicumyl peroxide, 2,4-dichlorobenzoyl peroxide, lauroyl Peroxides such as oxides, 2,2-bis- (4,4-t-butylperoxycyclohexyl) propane, tris- (t-butylperoxy) triazine; alkali metals, metal hydroxides, Grignard reagents, etc. Examples include nucleophiles, protonic acids, metal halides, and stable carbonium compounds.
The addition amount of a polymerization initiator is 0.1-20 mass% normally with respect to a polymerizable monomer, Preferably, it is 0.1-10 mass%. The polymerization initiator is preferably added after mixing and immediately before the granulation step.

Examples of the pigment include general-purpose black pigments, yellow pigments, magenta pigments, and cyan pigments. Examples of the black pigment include carbon black, aniline black, and acetylene black. Examples of yellow pigments include condensed azo compounds, isoindolinone compounds, anthraquinone compounds, azo metal complexes, methylene compounds, allylamide compounds, and the like. I. Pigment Yellow 12, 13, 14, 15, 17, 62, 74, 83, 93, 94, 95, 97, 109, 110, 111, 120, 127, 128, 129, 147, 155, 168, 174, 176, Preferable examples include 180, 181, 191 and the like.
Examples of magenta pigments include condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinones, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds, and perylene compounds. Specifically, C.I. I. Pigment Red 2, 3, 5, 6, 7, 23, 48: 2, 48: 3
48: 4, 57: 1, 81: 1, 122, 144, 146, 166, 169, 177, 184, 185, 202, 206, 220, 221, 238, 254, and the like.
Further, examples of cyan pigments include copper phthalocyanine compounds and derivatives thereof, anthraquinone compounds, basic dye lake compounds, and the like. I. Pigment Blue 1, 7, 15, 15: 1, 15: 2, 15: 3, 15: 4, 60, 62, 66 and the like can be preferably exemplified.
These pigments may be used alone or in combination of two or more.

Moreover, a pigment dispersant can also be used with a pigment. Examples of the pigment dispersant include aliphatic polycarboxylic acid polyester amine salts, polyether phosphate esters and amine salts thereof, and high molecular weight polyester acid amide amine salts.

  From the viewpoint of improving the fixing characteristics, it is preferable to use a release agent. Examples of the release agent include waxes such as paraffin wax, polyolefin wax, microcrystalline wax, Fischer-Tropsch wax, amide wax, higher fatty acids, A long chain alcohol or the like is used.

Moreover, it is preferable to add a crosslinking agent from a viewpoint of improving high temperature offset property. Cross-linking agents include hexanediol diacrylate, ethylene glycol diacrylate, ethylene glycol dimethacrylate, various poly (meth) acrylates of various polyols such as 1,3-butanediol dimethacrylate, aromatics such as divinylbenzene and divinylnaphthalene. Group divinyl compounds, divinyl compounds such as divinyl ether, and the like are used.
The addition amount of a crosslinking agent is about 0.001-10 mass parts normally with respect to 100 mass parts of polymerizable monomers.

Further, a dispersion stabilizer is preferably added. Examples of the dispersion stabilizer include tertiary calcium phosphate, sulfate such as barium sulfate and calcium sulfate; carbonate such as barium carbonate, calcium carbonate and magnesium carbonate; phosphoric acid such as calcium phosphate Salts: Metal oxides such as aluminum oxide and titanium oxide; Metal hydroxides such as aluminum hydroxide, magnesium hydroxide and ferric hydroxide; Water-soluble polymers such as polyvinyl alcohol, methylcellulose and gelatin; Anionic surface activity Agents, nonionic surfactants, amphoteric surfactants and the like.

Furthermore, a charge control agent can be added to improve the charging characteristics of the toner particles. Any charge control agent can be used without limitation as long as it is transparent and does not affect the degree of coloration of the toner particles and does not inhibit polymerization in the polymerization step. For example, various quaternary ammonium salts can be used. Compound, polymer compound having quaternary ammonium salt in side chain, guanidine compound, imidazole compound, metal salt of salicylic acid or alkylsalicylic acid with chromium, zinc, aluminum, etc., metal salt of higher fatty acid, metal complex, boron compound, Nigrosine dyes, amide group-containing compounds and the like are used.
Among them, a polymer compound having a quaternary ammonium salt in the side chain, more specifically, an acrylic resin having a quaternary ammonium salt-containing functional group having a mass molecular weight of 1000 to 18000 can be suitably used. Copolymer of aromatic hydrocarbon monomer, (meth) acrylate monomer and dimethylaminoethyl benzyl chloride chloride methacrylate (copolymerization molar ratio = 60: 5: 35 to 77: 20: 3; N% = 3 to 35) are preferable. Moreover, as long as it is comprised by the above polymerizable monomers, it is marketed as "Acrylic base FCA-201-PS", "No.271" [brand name made by Fujikura Kasei Co., Ltd.]. Can be used. The charge control agent may be determined by the charge amount desired for the toner particles, but is usually 0.1 to 10 parts by weight, preferably 0.5 to 5 parts by weight, more preferably 100 parts by weight of the toner particles. 0.5-3 mass parts is contained.

Next, an example of the procedure in the method for producing suspension polymerization toner particles of the present invention will be described.
First, the polymerizable monomer or a mixture thereof is mixed with a pigment, a pigment dispersant, and a release agent, and then sufficiently stirred to prepare a pigment dispersion.
Next, a charge control agent such as a quaternary ammonium salt compound, magnesium stearate and 2-phenylimidazole, and a crosslinking agent such as hexanediol diacrylate are added to this pigment dispersion and stirred sufficiently to form a polymerizable monomer. Etc. are prepared.
Next, a polymerization initiator such as 2,2'-azobis- (2,4-dimethylvaleronitrile) is added to this mixture, and then sufficiently stirred to prepare a polymerizable composition.
Separately, a dispersion stabilizer such as tricalcium phosphate is added to water to prepare an aqueous dispersant solution dissolved with hydrochloric acid or the like.
The aqueous dispersion solution is mixed with the polymerizable composition while stirring, an aqueous alkaline solution is added to precipitate the dispersion stabilizer, and then sufficiently stirred to prepare a suspension of the polymerizable composition. This suspension is stirred with a high-speed rotating stirrer to prepare a granulated liquid obtained by granulating the polymerizable composition.
Separately, resin fine particles are added to water and stirred with a high-speed rotating stirrer to prepare a dispersion of resin fine particles.
The polymerizable composition is mixed with a dispersion of resin fine particles and then heated to start suspension polymerization.
Suspension polymerization is performed at a temperature of about 50 to 100 ° C., preferably 60 to 80 ° C., with stirring, usually for about 6 to 12 hours.
Also, the polymerization composition is heated and polymerized without mixing with the resin fine particle dispersion, and the resin fine particle dispersion is added and mixed within a range where the polymerization rate is, for example, greater than 0 and 40% or less. You may do it. After the suspension polymerization is completed, the solid obtained by solid-liquid separation is washed with dilute hydrochloric acid or the like, then washed with ion exchange water or the like, and then sufficiently dried to obtain toner particles.

To the toner particles obtained by the above procedure, an external additive such as a fluidity imparting agent, an abrasive, a lubricant, and charge control particles is usually added.
As the fluidity-imparting agent, fine powders of metal oxides such as silicon oxide, aluminum oxide, titanium oxide, magnesium oxide, chromium oxide, tin oxide, and zirconium oxide can be used. Such an external additive is subjected to a surface treatment to increase hydrophobicity, thereby preventing deterioration of the flow characteristics and charging characteristics of the toner particles even under high humidity. For example, silane coupling agents, silicone oils, modified silicones and the like are preferable surface treatment agents. As abrasives, metal oxides such as strontium titanate, cerium oxide, aluminum oxide, magnesium oxide and chromium oxide, nitrides such as silicon nitride, carbides such as silicon carbide, metals such as calcium sulfate, barium sulfate and calcium carbonate A salt is preferably used. As the lubricant, fluorine resin powders such as vinylidene fluoride and polytetrafluoroethylene, and metal salts of fatty acids such as zinc stearate and calcium stearate are preferably used.
As the charge control particles, metal oxides such as tin oxide, titanium oxide, zinc oxide, silicon oxide, and aluminum oxide, carbon black, and the like are preferably used.
In addition, fine powder made of an organic polymer can be used. Of these external additives, hydrophobic silica, titanium oxide, and metal salts of fatty acids are preferred.
The addition amount of the external additive is usually 0.01 to 10 parts by mass, preferably 0.1 to 5 parts by mass with respect to 100 parts by mass of the toner particles in order to obtain good thermal stability. These external additives may be used alone or in combination of two or more.

The suspension-polymerized toner particles obtained by the production method of the present invention can be used as a one-component developer, or metal such as surface oxidized or unoxidized iron, nickel copper, zinc, cobalt, manganese chromium, rare earth, etc. Alternatively, a developing magnetic particle called carrier particles such as an alloy thereof, an oxide thereof, ferrite, or a magnetic dispersion resin can be added and used as a two-component developer.

EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited at all by these examples. Each characteristic was evaluated as follows.
<Preservation test>
3 g of each toner particle obtained in each example was sprayed in a container having a bottom area of 3.1 cm ² so as to have a uniform thickness, and the container was not covered and was kept in a thermostatic bath controlled at 60 ° C. for 12 hours. I left it alone.
Next, toner particle aggregates are formed on a sieve having openings of 106 μm, 63 μm, and 45 μm, each of which is set by overlapping each toner particle in a container taken out from the thermostat on a vibrating table of a powder tester (manufactured by Hosokawa Micron Corporation). It was transferred with care so as not to be destroyed as much as possible. Next, the vibration table was adjusted to have an amplitude of 1 mm / second and oscillated for 30 seconds, and the mass of toner particle aggregates remaining on a sieve having an aperture of 106 μm was measured. The aggregation rate of the toner particles was calculated from the mass of the toner particle aggregates and 3 g of the toner particles used in the test by the following formula, and used as an index of storage stability. The larger the numerical value in 5 stages in Table 1, the better the storage stability.
Aggregation rate = 100 × [3- (106 μm sieve residue)] / 3
Aggregation rate 90-100: 5
Aggregation rate less than 80-90: 4
Aggregation rate less than 70-80: 3
Aggregation rate of less than 50 to 70: 2
Aggregation rate 0 to less than 50: 1
<Fluidity test>
A sieve of a powder tester (manufactured by Hosokawa Micron Co., Ltd.) was set with a sieve having openings of 250 μm, 150 μm, and 75 μm in order from the top, and then adjusted so that the amplitude of the vibration table was 1 mm / second. Next, 2 g of the toner particles obtained in each example were weighed and gently placed on a sieve having an opening of 250 μm located at the uppermost position, and vibration was applied for 15 seconds. Thereafter, the mass of the toner particles remaining on each sieve was measured, and the degree of aggregation was calculated according to the following formula to obtain a fluidity index. It shows that it is excellent in fluidity | liquidity, so that the numerical value of a cohesion degree is small. The larger the numerical value in 5 stages in Table 1, the better the fluidity.
Aggregation degree = 100 × [(remaining amount on 250 μm sieve) × 5/10 + (remaining amount on 150 μm sieve) × 3/10 + (remaining amount on 75 μm sieve) × 1/10]
Aggregation degree 0-5: 5
Aggregation degree> 5-10: 4
Aggregation degree> 10-20: 3
Aggregation degree> 20-30: 2
Aggregation degree> 30-100: 1

<Fixability test>
With respect to the developer prepared from the toner particles obtained in each example, an unfixed image was prepared using a plain paper printer (manufactured by Kyocera Mita Co., Ltd., modified LS-C8008N).
The unfixed image was fixed by a fixing jig modified so that the temperature of the fixing roll portion could be adjusted, and the test was performed.
By changing the temperature of the fixing jig from 140 to 210 ° C. in increments of 10 ° C., observing the fixing state of the developer at each temperature, and then visually observing the peeling state by the tape peeling operation, the following five levels of criteria Was evaluated. The larger the numerical value in 5 steps in Table 1, the better the fixing property. When the temperature was changed, it was left for 5 minutes or more in order to stabilize the temperature of the fixing roll.
No peeling: 5
Partial peeling (no problem): 4
Partial peeling (problems): 3
Nearly half peeled: 2
More than half peeled: 1
<Image characteristics>
For the developer prepared from the toner particles obtained in each example, an image was obtained using a plain paper printer (manufactured by Kyocera Mita Co., Ltd., LS-C8008N) under normal pressure of 20 ° C. and 40% RH. The film was visually observed for fogging, filming and followability, and the presence or absence of fogging, filming and followability was evaluated according to the following five criteria.
None. No problem: 5
Almost none. Almost no problem: 4
There are some: 3
There is significantly. Bad: 2
It is all over. Extremely bad: 1
<Measurement of polymerization rate>
1 g each of the mixed solution before the start of heating polymerization and the toner particle suspension after the start of heating were collected and dissolved in 4 ml of THF. It was measured by gas chromatography with an internal standard.
Gas chromatography measurement conditions are as follows.
Measuring device: N ₂ , 2 kg / cm ² , 50 ml / min
Split ratio: 1/60
Linear velocity: 30mm / sec Column: ULBON HR-1 50m x 0.25

Example 1
In 75 parts by mass of styrene, 25 parts by mass of butyl acrylate, 5 parts by mass of wax (paraflint HIT) manufactured by SASOL as a release agent, and magenta pigment (C.I.
Pigment Red 238) 7 parts by weight, 1.4 parts by weight of a high molecular weight polyester acid amide amine (mass average molecular weight thousands to tens of thousands, acid value 15, amine value 40) as a pigment dispersant are weighed and stirred with a ball mill for 20 hours. Thus, a pigment dispersion of a polymerizable monomer was obtained. In this pigment dispersion, 1 part by mass of a charge control agent having a quaternary ammonium salt-containing functional group [manufactured by Orient Chemical Co., Ltd., Bontron P-51], 0.4 parts by mass of magnesium stearate, 2-phenylimidazole, 0. 2 parts by mass and 0.2 part by mass of hexanediol diacrylate as a crosslinking agent were added and mixed well to obtain a dispersion.
Next, 3 parts by mass of 2,2′-azobis- (2,4-dimethylvaleronitrile) is added to the dispersion as a polymerization initiator and mixed thoroughly to obtain an oil phase (polymerizable monomer). Composition) was obtained.
Separately, 10 parts by mass of tertiary calcium phosphate as a dispersion stabilizer was added to 380 parts by mass of distilled water, and the aqueous phase was obtained by dissolving the calcium phosphate with 90 parts by mass of 2 mol / liter hydrochloric acid. Next, the oil phase was added to this aqueous phase with stirring, and 60 parts by mass of a 4 mol / liter sodium hydroxide aqueous solution was added to precipitate calcium phosphate, followed by thorough mixing to obtain a suspension. .
This suspension was stirred for 15 minutes at 9,000 rotations per minute using a high-speed stirrer “CLEAMIX CLM-5S” manufactured by M Technique Co., Ltd. to prepare a granulated liquid.
Separately, an acrylic resin [isobonyl methacrylate / t-butyl methacrylate / methyl methacrylate (copolymerization molar ratio: 60/35/5) copolymer prepared by a known emulsion polymerization method, gel permeation chromatography ( 2 parts by mass of fine particles (average particle diameter: 400 nm, glass transition temperature: 128 ° C.) measured by GPC) method were added to 40 parts by mass of distilled water, and then “CLEARMIX CLM-5S ”Was stirred at a rotational speed of 6,000 times per minute for 5 minutes to prepare a dispersion of acrylic resin fine particles.
This dispersion of acrylic resin fine particles was put into the granulation liquid and sufficiently mixed with a stirrer.
This mixed solution was heated at 60 ° C. for 6 hours, and then further heated at 80 ° C. for 3 hours to perform suspension polymerization to obtain a suspension of toner particles. Subsequently, the suspension was solid-liquid separated, washed with dilute hydrochloric acid and water with ion-exchanged water, and sufficiently dried to obtain toner particles. The polymerization rate of the polymerizable monomer in the granulation liquid before mixing with the dispersion of acrylic resin fine particles is 0%.
The toner particles obtained above had an average particle size of 7.1 μm. Next, 2.0 parts by mass of hydrophobic silica was externally added to 100 parts by mass of the obtained toner particles. Further, 97 parts by mass of a ferrite carrier (particle diameter: 50 μm) surface-treated with a hydrophobic resin was added to 3 parts by mass of the externally added toner particles and mixed well to obtain a developer.
The obtained toner particles were measured for storage stability and fluidity, and image characteristics of the developer were evaluated. The results are shown in Table 1.

Example 2
Acrylic resin prepared by a known emulsion polymerization method [copolymer of isobornyl methacrylate / t-butyl methacrylate / methyl methacrylate (copolymerization molar ratio: 60/35/5), gel permeation chromatography (GPC) The toner particles were obtained in the same manner as in Example 1 except that the fine particles (average particle size: 100 nm, glass transition temperature: 128 ° C.) having a mass average molecular weight of 200,000] measured by the method were used. The obtained toner particles had an average particle size of 7.3 μm. Next, the obtained toner particles were externally added and surface-treated with a hydrophobic resin in the same manner as in Example 1 to obtain a developer.
Each characteristic was evaluated in the same manner as in Example 1 using the obtained toner particles and developer. The results are shown in Table 1.

Example 3
Acrylic / styrene resin produced by a known emulsion polymerization method [copolymer of isobornyl methacrylate / styrene (copolymerization molar ratio: 45/55), mass average molecular weight measured by gel permeation chromatography (GPC) method : 150,000] fine particles (average particle size: 400 nm, glass transition temperature: 105 ° C.), toner particles were obtained in the same manner as in Example 1. The obtained toner particles had an average particle diameter of 7.2 μm. Next, the obtained toner particles were externally added and surface-treated with a hydrophobic resin in the same manner as in Example 1 to obtain a developer. Each characteristic was evaluated in the same manner as in Example 1 using the obtained toner particles and developer. The results are shown in Table 1.

Example 4
About 120 minutes after heating the granulation liquid to 60 ° C., the same procedure as in Example 1 was conducted except that the dispersion of acrylic resin fine particles was slowly added when the polymerization rate of the polymerizable monomer reached 30%. To obtain toner particles. The obtained toner particles had an average particle diameter of 7.1 μm. Next, the obtained toner particles were externally added and surface-treated with a hydrophobic resin in the same manner as in Example 1 to obtain a developer. Each characteristic was evaluated in the same manner as in Example 1 using the obtained toner particles and developer. The results are shown in Table 1.

Example 5
Toner particles were obtained in the same manner as in Example 4 except that the acrylic resin fine particles used in Example 2 were used. The obtained toner particles had an average particle diameter of 7.1 μm. Next, the obtained toner particles were externally added and surface-treated with a hydrophobic resin in the same manner as in Example 1 to obtain a developer.
Each characteristic was evaluated in the same manner as in Example 1 using the obtained toner particles and developer. The results are shown in Table 1.

Comparative Example 1
Toner particles (average particle size 6.8 μm) and developer are obtained in the same manner as in Example 1 without adding the acrylic resin fine particle dispersion. Each characteristic was evaluated in the same manner as in Example 1 using the obtained toner particles and developer. The results are shown in Table 1.

Comparative Example 2
About 6 hours after heating the granulation liquid to 60 ° C., when the polymerization rate of the polymerizable monomer reached 97%, except that the dispersion of acrylic resin fine particles was slowly added, and Example 1 In the same manner, toner particles were obtained. The obtained toner particles had an average particle size of 6.9 μm. Next, the obtained toner particles were processed in the same manner as in Example 1 to obtain a developer.
Each characteristic was evaluated in the same manner as in Example 1 using the obtained toner and developer. The results are shown in Table 1.

Comparative Example 3
Acrylic resin prepared by a known emulsion polymerization method [copolymer of isobornyl methacrylate / t-butyl methacrylate / methyl methacrylate (copolymerization molar ratio: 60/35/5), gel permeation chromatography (GPC) Toner particles (average particle size 7.2 μm), except that the average particle size was 160,000] (average particle size: 800 nm, glass transition temperature: 128 ° C.). ) And a developer were obtained. Each characteristic was evaluated in the same manner as in Example 1 using the obtained toner particles and developer. The results are shown in Table 1.

Comparative Example 4
After the granulation liquid was heated to 60 ° C. and after 180 minutes, when the polymerization rate of the polymerizable monomer reached 50%, it was the same as in Example 1 except that the dispersion of acrylic resin fine particles was slowly added. To obtain toner particles. The obtained toner particles had an average particle size of 7.3 μm. Next, the obtained toner particles were externally added and surface-treated with a hydrophobic resin in the same manner as in Example 1 to obtain a developer. Each characteristic was evaluated in the same manner as in Example 1 using the obtained toner and developer. The results are shown in Table 1.

Comparative Example 5
Acrylic resin prepared by a known emulsion polymerization method [copolymer of isobornyl methacrylate / t-butyl methacrylate / methyl methacrylate (copolymerization molar ratio: 60/35/5), gel permeation chromatography (GPC) The toner particles were obtained in the same manner as in Example 1 except that the particles were changed to fine particles (average particle diameter: 600 nm, glass transition temperature: 128 ° C.) having a mass average molecular weight of 150,000] measured by the method. The obtained toner particles had an average particle size of 7.3 μm. Next, the obtained toner particles were externally added and surface-treated with a hydrophobic resin in the same manner as in Example 1 to obtain a developer. Each characteristic was evaluated in the same manner as in Example 1 using the obtained toner particles and developer. The results are shown in Table 1.

Comparative Example 6
Acrylic / styrene resin [butyl acrylate / styrene (copolymerization molar ratio: 10/90) copolymer prepared by a known emulsion polymerization method, mass average molecular weight measured by gel permeation chromatography (GPC) method: 180,000] fine particles (average particle size: 400 nm, glass transition temperature: 75 ° C.), except that toner particles were obtained in the same manner as in Example 1. The obtained toner particles had an average particle size of 6.9 μm. Next, the obtained toner particles were externally added and surface-treated with a hydrophobic resin in the same manner as in Example 1 to obtain a developer. Each characteristic was evaluated in the same manner as in Example 1 using the obtained toner particles and developer. The results are shown in Table 1.

Comparative Example 7
Acrylic / styrene resin prepared by a known emulsion polymerization method [Methyl methacrylate / styrene (copolymerization molar ratio: 85/15) copolymer, mass average molecular weight measured by gel permeation chromatography (GPC) method: 180,000] fine particles (average particle size: 400 nm, glass transition temperature: 170 ° C.), except that toner particles were obtained in the same manner as in Example 1. The obtained toner particles had an average particle size of 7.0 μm. Next, the obtained toner particles were externally added and surface-treated with a hydrophobic resin in the same manner as in Example 1 to obtain a developer. Each characteristic was evaluated in the same manner as in Example 1 using the obtained toner particles and developer. The results are shown in Table 1.

  In Table 1, the indication of A / S of the resin fine particle type indicates acrylic / styrene resin. As is clear from the results in Table 1, it can be seen that the toner particles and the developer of each example have no problem with respect to most of the characteristics, and only a few characteristics have practically no problem. On the other hand, it can be seen that in the comparative example, there is a problem in most characteristics, or it is defective or remarkably defective and cannot be put to practical use.

The toner particles obtained by the production method of the present invention are excellent in storage stability and fluidity, and have high image quality and excellent print quality when used for electrophotography, electrostatic recording, electrostatic printing and the like. Printed materials can be provided.

Claims (7)

In producing a suspension polymerization toner particle by polymerizing a polymerizable monomer for toner particle formation in a dispersion medium, the mixture of the polymerizable monomer and resin fine particles is polymerized, or a part thereof is polymerized. A method for producing suspension-polymerized toner particles, comprising polymerizing the polymerizable monomer and resin fine particles in a state of being mixed. 2. The method for producing suspension-polymerized toner particles according to claim 1, wherein the resin fine particles have a glass transition temperature of 80 to 150 ° C. and a particle diameter of 50 to 500 nm. The method for producing suspension-polymerized toner particles according to claim 1, wherein the resin fine particles are resin fine particles dissolved in the polymerizable monomer.   The method for producing suspension polymerized toner particles according to any one of claims 1 to 3, wherein the resin fine particles are mixed within a range in which the polymerization rate of the polymerizable monomer is greater than 0 and 40% or less.   The method for producing suspension-polymerized toner particles according to claim 1, wherein the resin fine particles are styrene resin or styrene-acrylic resin.   The method for producing suspension-polymerized toner particles according to claim 1, wherein the resin fine particles are a resin modified with a functional group-containing compound. Suspension polymerization toner particles obtained by the production method according to claim 1.