JP6800765B2 - Method of manufacturing resin particles - Google Patents

Description

The present invention relates to a method for producing resin particles that reduces organic volatile substances contained in the resin particles.

In recent years, various environmental standards have set standard values for the amount of organic volatile substances in chemical products. Proposals for the removal of organic volatile substances in chemical products have been actively made in order to comply with such environmental standards.
In Patent Document 1, a treatment liquid containing an organic volatile substance is circulated in a circulation system incorporating an evaporation container, water vapor is introduced into the circulation path, and the treatment liquid is dispersed and discharged to distill. The method is disclosed.
Patent Document 2 discloses a method for removing organic volatile substances, in which a treatment liquid extracted from an evaporation container is heated by a heating device provided in a circulation path and the heated treatment liquid is returned to the evaporation container.
Although these methods can remove organic volatile substances, their effects are limited because the amount of heat applied to the treatment liquid is limited, so that the treatment time is long and the organic volatile substances that can be removed are limited. In addition, resin particles adhere to the pump or heating device that circulates the treatment liquid, which lowers the efficiency of removing volatile substances and reduces productivity because the device must be stopped to remove the adhesion. There was a problem of letting them do it.
Organic volatile substances are also used in wet toner particle production methods such as suspension polymerization methods using polymerizable monomers, emulsion polymerization aggregation methods, and dissolution / suspension methods in which binder resins are granulated in a solvent. Proposals for the removal of the solvent are being actively made.
If a large amount of organic volatile substances such as polymerizable monomers and by-products are present in the toner particles, the fluidity of the toner may decrease, which may worsen the working environment or generate an unpleasant odor. In particular, in recent years, there has been increasing concern about the environment, and it is required to reduce the volatile components derived from toner particles generated in the heat-pressurized fuser.
In Patent Document 3, the pressure of the evaporation container and the external circulation path is reduced, the dispersion liquid of the particles is extracted from the evaporation container to the external circulation path, heated by an external heat exchanger and returned to the evaporation container to remove organic volatile substances. The method of doing so is disclosed.
Although it is possible to reduce the amount of organic volatile substances in the particles by this method, the effect is limited due to the small amount of heat given, and it is difficult to fully meet the recent demand for removal of organic volatile substances. is there. In addition, particles adhere to the pump or heating device that circulates the treatment liquid, which reduces the efficiency of removing organic volatile substances and reduces productivity because the device must be stopped to remove the adhesion. It may cause you to do so.
In Patent Document 4, a dispersion of particles in an evaporation vessel is extracted and sent to an external circulation path, and saturated water vapor of 100 ° C. or higher is blown into the external circulation path to produce toner particles for removing organic volatile substances. The method is disclosed.
Although this method significantly improves the removal efficiency of organic volatile substances as compared with the conventional method, it is difficult to sufficiently meet the recent demand for removal of organic volatile substances. In addition, since the pump is used to circulate the treatment liquid, the problem of particle adhesion to the pump remains.
Patent Document 5 is a method for distilling a cleaning liquid, which is different from the removal of organic volatile substances from chemical products. Patent Document 5 discloses, as a method for distilling and regenerating the cleaning liquid, a method of sending the cleaning liquid in the evaporation container to an external circulation path and passing it through an ejector incorporated in the external circulation path. In this method, gas is drawn into the ejector to put it in a pressurized state, and then the pressure is released by returning the pressurized cleaning liquid to the evaporation container, and this pressure change is used to evaporate and distill the organic volatile substances in the cleaning liquid. It is carried out.
This method can evaporate the organic volatiles in the liquid, but its effect is limited when removing the organic volatiles in the chemical product. In addition, since a pump is used to send the cleaning liquid to the external circulation path, there is a problem of adhesion to the pump. As a method of circulating the liquid instead of the pump that causes clogging, the use of an ejector without a mechanical moving part can be considered. However, the performance of the ejector is determined by the shape, and the shape cannot be changed after manufacturing, so it is necessary to design an appropriate shape according to the treatment liquid.
As a method of reducing the organic volatile substances contained in the resin particles, a method of additionally adding a polymerization initiator in the latter half of the step of polymerizing the resin particles can be considered. Further, a method is disclosed in which an effect other than the effect of reducing organic volatile components can be obtained by additionally adding a polymerization initiator. In Patent Document 6, a polymer having a sulfonic acid-based functional group is uniformly immobilized on the surface of the toner by adding a water-soluble initiator in the latter half of the polymerization of the toner. As a result, the environmental stability and cleanability of the toner are improved.
Further, in Patent Document 7, the core and shell of the toner are polymerized separately by adding a monomer and a water-soluble initiator in the latter half of the polymerization of the toner. As a result, fixability and storage stability are improved.
In Patent Document 8, the amount of organic volatile substances in the binder resin for toner is reduced by adding two kinds of polymerization initiators and undergoing a two-step process having different reaction temperatures. Further, in the second step, the whole reaction system is pressurized to react at a temperature of 110 ° C. or higher. In this method, organic volatile substances can be reduced by adding two kinds of polymerization initiators and reacting at a temperature of 110 ° C. or higher. However, in the second step, since the entire reaction system is pressurized, the organic volatile substances cannot be removed from the reaction system during the reaction, and there is a problem that the efficiency of reducing the organic volatile substances is poor. Further, since the toner is reacted at a high temperature of 110 ° C. or higher, there is a problem that the toner softens and coalescence with each other occurs.

Japanese Patent No. 4866378 Japanese Unexamined Patent Publication No. 5-194624 Japanese Patent No. 4092528 Japanese Patent No. 5376959 Japanese Unexamined Patent Publication No. 2004-105845 Japanese Patent No. 5137702 Japanese Patent No. 3195362 Japanese Unexamined Patent Publication No. 2000-172010

The present invention is to provide a method for producing resin particles that solves the above-mentioned problems.
That is, the present invention provides a method for producing resin particles using an organic volatile substance removing device, which has high reduction efficiency of organic volatile substances, less adhesion to the device, and less coalescence of resin particles.

As a result of diligent studies on the reduction of organic volatile substances and the suppression of adhesion of the processed material to the apparatus, the present inventors have found the following methods for producing resin particles and toner particles.
That is, a preparation step for preparing an aqueous medium containing poorly water-soluble inorganic fine particles, and
A granulation step of forming particles of a polymerizable monomer composition containing a polymerizable monomer in the aqueous medium, and
A polymerization step of polymerizing the polymerizable monomer contained in the particles of the polymerizable monomer composition to obtain resin particles,
A method for producing resin particles, which comprises an organic volatile substance removing step of removing an organic volatile substance from the resin particles.
In the polymerization step, a polymerization initiator is added when the conversion rate of the polymerizable monomer contained in the particles of the polymerizable monomer composition is 90.0% or more.
The polarity of the ionic residue derived from the polymerization initiator and the polarity of the poorly water-soluble inorganic fine particles are opposite, and in the organic volatile substance removal step, the evaporation container and the organic volatilization having an external circulation path connected to the evaporation container. A substance removal device is used, and an ejector is provided in the external circulation path.
The ejector is
(I) Casing and
(Ii) A blowing nozzle that blows gas into the casing,
(Iii) A suction port for sucking the liquid discharged from the evaporation container into the casing by the action of the gas blown into the casing.
(Iv) A discharge nozzle for discharging the liquid and the gas from the casing to the external circulation path, and
It is a method for producing resin particles, which is characterized by having.

According to the present invention, it is possible to provide a method for producing resin particles using an organic volatile substance removing device, which has high reduction efficiency of organic volatile substances, less adhesion to the device, and less coalescence of resin particles.

It is the schematic which shows an example of the organic volatile substance removal apparatus applicable to this invention. It is the schematic of the ejector applicable to this invention. It is the schematic which shows an example of the conventional organic volatile substance removal apparatus. It is the schematic which shows an example of the conventional organic volatile substance removal apparatus.

Hereinafter, the present invention will be described in detail.

The method for producing resin particles of the present invention is suitably applied for the purpose of reducing organic volatile substances from resin particles used as raw materials for various chemical products. In particular, it can be suitably used for the purpose of reducing organic volatile substances contained in toner particles.

Hereinafter, as an example thereof, a case where the present invention is used in a method for producing a toner by a suspension polymerization method will be described.

In the suspension polymerization method, particles of a polymerizable monomer composition containing a polymerizable monomer and a colorant are formed in an aqueous medium, and the polymerizable simpler is contained in the particles of the polymerizable monomer composition. This is a production method for obtaining toner particles by polymerizing a monomer.

Hereinafter, a method for producing toner particles by the suspension polymerization method will be described for each step.

(Polymerizable monomer composition preparation step)
A polymerizable monomer composition containing a polymerizable monomer and a colorant is prepared. The colorant may be dispersed in the polymerizable monomer in advance with a medium stirring mill or the like and then mixed with other compositions, or all the compositions may be mixed and then dispersed.

(Granulation process)
The polymerizable monomer composition is put into an aqueous medium containing poorly water-soluble inorganic fine particles and dispersed to obtain granules to obtain a dispersion liquid in which the particles of the polymerizable monomer composition are dispersed. The granulation step can be performed, for example, in a vertical stirring tank equipped with a stirrer having a high shearing force. The stirrer having a high shearing force is not particularly limited, but for example, a high share mixer (manufactured by IKA), T.I. K. Homomixer (manufactured by Tokushu Kagaku Kogyo Co., Ltd.), T. K. Commercially available products such as Philmix (manufactured by Tokushu Kagaku Kogyo Co., Ltd.) and Claremix (manufactured by M Technique) can be used.

Examples of the poorly water-soluble inorganic fine particles include carbonates such as barium carbonate, calcium carbonate and magnesium carbonate; metal phosphates such as aluminum phosphate, magnesium phosphate, calcium phosphate, barium phosphate and zinc phosphate; barium sulfate, Sulfates such as calcium sulfate; calcium hydroxide, aluminum hydroxide, magnesium hydroxide, ferric hydroxide metal hydroxide; and the like can be mentioned. These can be used alone or in combination of two or more. These exhibit a function as a dispersion stabilizer by being present as fine particles in an aqueous medium.

(Polymerization process)
In the dispersion obtained as described above, the polymerizable monomer in the particles of the polymerizable monomer composition is polymerized. In the polymerization step in the present invention, a general stirring tank whose temperature can be adjusted can be used. The method of polymerization is not particularly limited, but it is preferable to add a polymerization initiator to the dispersion and polymerize at a polymerization temperature of 40 ° C. or higher, generally 50 to 90 ° C. The polymerization temperature may be constant from beginning to end, but may be gradually raised. The polymerization initiator may be added in advance to the polymerizable monomer composition. Any stirring blade used for stirring may be used as long as the polymerizable monomer composition dispersion can be suspended without staying and the temperature in the tank can be kept uniform. As the stirring blade or stirring means, general stirring blades such as paddle blades, inclined paddle blades, three swept blades, propeller blades, disc turbine blades, helical ribbon blades and anchor blades, and "full zone" (Shinko Pantech) "Twin Star" (manufactured by Shinko Pantech), "Max Blend" (manufactured by Sumitomo Heavy Industries), "Super Mix" (manufactured by Satake Chemical Machinery Co., Ltd.) and "Hi-F Mixer" (manufactured by Soken Kagaku Co., Ltd.) (Made) and so on.

When the conversion rate of the polymerizable monomer contained in the particles of the polymerizable monomer composition is 90.0% or more, the polarity of the ionic residue derived from the polymerization initiator and the electricity of the poorly water-soluble inorganic fine particles A polymerization initiator (hereinafter, also referred to as “polymerization initiator B”) having a reverse polarity is added. The polarity of the poorly water-soluble inorganic fine particles is specified from the zeta potential of the poorly water-soluble inorganic fine particles in an aqueous medium. A polymerization initiator that produces an ionic residue is a water-soluble initiator, but if a water-soluble polymerization initiator is added when the conversion rate is less than 90.0%, physical properties such as the molecular weight of the toner binder Will change. When the molecular weight changes, physical properties such as toner fixability, durability, and storage stability change.

Further, by using the above-mentioned polymerization initiator B, the ionic residue derived from the polymerization initiator B at the end of the polymer formed by polymerizing the polymerizable monomer is contained in the aqueous medium, that is, the particles. When a large amount is present on the surface, a large amount of water-insoluble inorganic fine particles having a polarity opposite to that of the ionic residue are adsorbed on the particle surface by the Coulomb force. As a result, coalescence of particles can be suppressed.

Further, it is preferable that the electrical polarity of the ionic residue derived from the polymerization initiator B is negative. Since the anion has a larger ionic radius and is stronger than the cation, more water-soluble inorganic fine particles having opposite polarities are adsorbed on the particle surface and the effect of suppressing the coalescence of the particles is high.

Further, it is preferable that the polymerization initiator B is a persulfate compound. Since the negative electrode property of the sulfate ion is stronger than that of other anions, more water-soluble inorganic fine particles having opposite polarities are adsorbed on the particle surface, and the effect of suppressing the coalescence of the particles is high. Furthermore, since the radicals generated from the persulfate compound are more potent, the effect of reducing organic volatile substances is also higher, which is preferable.

Furthermore, when the average value of the zeta potential values of the poorly water-soluble inorganic fine particles under the conditions of the actual toner manufacturing process is ζ,
0.0mV <ζ≤20.0mV
Is preferable. When the zeta potential value of the poorly water-soluble inorganic fine particles is 0.0 mV <ζ, that is, the positive electrode property, a large amount of the poorly water-soluble inorganic fine particles are adsorbed on the surface of the negative electrode particles, and coalescence of the particles can be suppressed, which is preferable. .. In addition, since the zeta potential value of the poorly water-soluble inorganic fine particles is ζ ≦ 20.0 mV, other particles are adsorbed by the Coulomb force to the particles on which many poorly water-soluble inorganic fine particles are adsorbed, and the particles are aggregated. It is preferable because it can prevent this.

(Organic volatile substance removal process)
Subsequently, the organic volatile substance in the particle dispersion obtained through the polymerization step is removed. As the organic volatile substance removing device used in the organic volatile substance removing step, for example, the removing device shown in FIG. 1 can be used. The organic volatile substance removing device 1 is provided with an evaporation container 2 and an external circulation path 3 connected to the evaporation container. The evaporation vessel may be provided with a stirring blade 10. The external circulation path 3 is provided with the ejector 4 shown in FIG. The ejector 4 has a casing 5, a blowing nozzle 6 for blowing gas into the casing, and an suction port 9 for sucking a liquid (dispersion liquid) discharged from an evaporation container.

The shape of the blowing nozzle 6 is not particularly limited, but it is preferable to reduce the cross-sectional area of a part of the blowing nozzle. By reducing the cross-sectional area, the flow velocity of the gas can be increased and the Venturi effect can be effectively generated. The portion for reducing the cross-sectional area is preferably inside the casing 5 and close to the tip of the blowing nozzle. By being close to the tip, the Venturi effect can be suitably applied. The gas blown from the blowing nozzle is in a negative pressure state near the outlet of the blowing nozzle, so that the dispersion liquid is sucked into the casing 5 from the suction port 9 and mixed with the gas.

The dispersion liquid and the gas thus mixed are discharged from the discharge nozzle 7 to the external circulation path in a mixed state. The shape of the discharge nozzle 7 is not particularly limited, but it is preferable that the cross-sectional area of the discharge nozzle increases toward the outside of the casing. By increasing the cross-sectional area of the discharge nozzle toward the outside of the casing from a small state, it is possible to efficiently generate the effect of circulating the dispersion liquid and the gas mixture by the blown gas in the external circulation path. The blowing nozzle 6 and the discharging nozzle 7 are not particularly limited, but are preferably installed at opposite positions.

In the ejector 4 having the above-mentioned preferable form, the dispersion liquid is sucked into the inside of the ejector and discharged from the discharge nozzle due to the Venturi effect generated by blowing the gas from the blowing nozzle 6. At this time, since the dispersion liquid and the gas are mixed inside the ejector, the gas-liquid interface between the dispersion liquid and the gas increases. This is preferable because the organic volatile substances in the dispersion liquid are efficiently transferred to the gas side and the organic volatile substances are efficiently removed. Further, as compared with the conventional method in which the dispersion liquid is sent to the external circulation path by the pump 8 as shown in FIG. 3 and the gas is blown from the gas blowing port 13 provided in the external circulation path, more gas is blown. It is preferable because it can efficiently remove organic volatile substances.

As in the organic volatile substance removing device in FIG. 1, it is preferable that the dispersion liquid passes through the external circulation path and returns to the evaporation container by the action of the blown gas. If it is circulated by a pump or other mechanical power, particles in the dispersion liquid may adhere to a circulatory device such as a pump and deteriorate the circulation function.

As the gas to be blown into the blowing nozzle 6, various gases such as helium, neon, argon, krypton, radon, nitrogen, carbon dioxide, water vapor, air, and ozone can be selected. As the gas, it can be used alone, or two or more can be used in combination at an arbitrary ratio. Among the gases, it is more preferable to use water vapor. Water vapor has a large low-pressure molar heat capacity among many gases, and is more preferable because it can efficiently remove organic volatile substances. Further, it is preferable to recover the gas immediately after the mixture of the dispersion liquid and the gas returns to the evaporation vessel from the external circulation path. If the amount of gas recovered is less than the amount of gas blown in, the pressure in the evaporation vessel may increase and the circulation of the dispersion liquid may be delayed. When the gas is water vapor, it is preferable because the water vapor can be recovered by various condensers. Further, when the dispersion medium of the dispersion liquid is an aqueous dispersion medium, by using water vapor, there is almost no influence such as a change in pH due to the dissolution of the gas in the dispersion medium, and the influence on the particles in the dispersion liquid is small. It can be preferably used.

In the organic volatile substance removal step, when the temperature at which the aqueous medium containing the resin particles circulates in the external circulation path is T.
100.0 ° C ≤ T ≤ 160.0 ° C
Is preferable. When the temperature at the time of circulation is 100.0 ° C. or higher, organic volatile substances can be efficiently removed, which is preferable. Further, when the temperature at the time of circulation is 160.0 ° C. or lower, pressure fluctuation in the inside of the ejector and the external circulation path is suppressed, and the circulation of the dispersion liquid is stable, which is preferable. When the circulation becomes unstable, heat is locally applied and particles in the dispersion liquid adhere to a part of the external circulation path, so that the circulation cannot be performed. When the temperature at the time of circulation exceeds 100 ° C., it is possible to raise the temperature to exceed 100 ° C. by narrowing the back pressure valve 14 and putting the inside of the external circulation path 3 in a pressurized state.

(Washing process, solid-liquid separation process and drying process)
The dispersion is treated with an acid or alkali for the purpose of removing the dispersion stabilizer adhering to the surface of the obtained particles. After this, the particles are separated from the liquid phase by a general solid-liquid separation method, but the particles are washed again with water in order to completely remove the acid or alkali and the dispersion stabilizer component dissolved therein. This washing step is repeated several times, and after sufficient washing is performed, solid-liquid separation is performed again. Then, it is dried by a known drying means.

(Classification process)
The particles thus obtained have a sufficiently sharp particle size as compared with the conventional pulverized toner, but when a sharper particle size is required, it is desired to classify the particles with a wind classifier or the like. Particles that deviate from the particle size distribution can also be separated and removed.

Hereinafter, various materials used in the production of toner particles by the suspension polymerization method will be described.

(Charge control agent)
A known charge control agent can be used in the toner obtained by the production method of the present invention. The content of the charge control agent is preferably 0.01 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the polymerizable monomer.

(Pigment)
The toner obtained by the production method of the present invention contains a pigment as a colorant. As the pigment used for the cyan-based colorant, a copper phthalocyanine compound and its derivative, an anthraquinone compound, and a basic dye lake compound can be used. Specifically, the following can be mentioned. C. I. Pigment Blue 15, C.I. I. Pigment Blue 15: 1, C.I. I. Pigment Blue 15: 2, C.I. I. Pigment Blue 15: 3 and C.I. I. Pigment Blue 15: 4.

As the pigment used for the magenta colorant, a condensed azo compound, a diketopyrrolopyrrole compound, anthraquinone, a quinacridone compound, a basic dye lake compound, a naphthol compound, a benzimidazolone compound, a thioindigo compound and a perylene compound can be used. Specifically, the following can be mentioned. C. I. Pigment Violet 19, C.I. I. Pigment Red 31, C.I. I. Pigment Red 57, C.I. I. Pigment Red 122, C.I. I. Pigment Red 150 and C.I. I. Pigment Red 269.

As the pigment used for the yellow colorant, a condensed azo compound, an isoindolinone compound, an anthraquinone compound, an azo metal complex, a methine compound and an allylamide compound can be used. Specifically, the following can be mentioned. C. I. Pigment Yellow 74, C.I. I. Pigment Yellow 93, C.I. I. Pigment Yellow 120, C.I. I. Pigment Yellow 151, C.I. I. Pigment Yellow 155, C.I. I. Pigment Yellow 180 and C.I. I. Pigment Yellow 185.

As the black colorant, carbon black, a magnetic material, and those colored black using the above-mentioned yellow, magenta, and cyan colorants can be used.

The amount of these pigments added is preferably 1 part by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the polymerizable monomer.

(wax)
The toner obtained by the production method of the present invention may contain wax. In that case, at least one of the waxes preferably has a melting point (temperature corresponding to the maximum endothermic peak of the DSC endothermic curve in the temperature range of 20 to 200 ° C.) of 30 ° C. or higher and 120 ° C. or lower, and 50 ° C. or higher and 100 ° C. The following is more preferable. Further, it is preferably a wax that is solid at room temperature, and a solid wax having a melting point of 50 ° C. or higher and 100 ° C. or lower is particularly preferable from the viewpoint of toner blocking resistance, multi-sheet durability, low temperature fixability, and offset resistance.

Examples of the wax include paramethylene wax, polyolefin wax, microcrystallin wax, polymethylene wax such as Fishertropsh wax, petroleum wax such as amide wax and petrolatum and its derivatives, Montan wax and its derivatives, carnauba wax and candelilla wax. Use known waxes such as natural waxes and their derivatives, hardened castor oil and its derivatives, vegetable waxes, animal waxes, higher fatty acids, long chain alcohols, ester waxes, ketone waxes and their graft compounds, block compounds and other derivatives. Is possible. These can be used alone or in combination.

(Polymerizable monomer)
Specific examples of the polymerizable monomers that can be used are as shown below. Styline; α-methylstyrene, β-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, 2,4-dimethylstyrene, pn-butylstyrene, p-tert-butylstyrene, p- Styrene derivatives such as n-hexylstyrene, pn-octylstyrene, pn-nonylstyrene, pn-decylstyrene, pn-dodecylstyrene, p-methoxystyrene, p-phenylstyrene; methylacrylate, Ethyl acrylate, n-propyl acrylate, iso-propyl acrylate, n-butyl acrylate, iso-butyl acrylate, tert-butyl acrylate, n-amyl acrylate, n-hexyl acrylate, 2-ethylhexyl acrylate, n-octyl acrylate, n- Acrylic polymerizable monomers such as nonyl acrylate, cyclohexyl acrylate, benzyl acrylate, dimethyl phosphate ethyl acrylate, diethyl phosphate ethyl acrylate, dibutyl phosphate ethyl acrylate, 2-benzoyloxyethyl acrylate; methyl methacrylate, ethyl methacrylate, n -Propyl methacrylate, iso-propyl methacrylate, n-butyl methacrylate, iso-buty methacrylate, tert-butyl methacrylate, n-amyl methacrylate, n-hexyl methacrylate, 2-ethylhexyl methacrylate, n-octyl methacrylate, n-nonyl methacrylate, diethyl Methacrylate-based polymerizable monomers such as phosphate ethyl methacrylate and dibutyl phosphate ethyl methacrylate.

(Polymer initiator)
Examples of the polymerization initiator (hereinafter, also referred to as “polymerization initiator A”) added first in the polymerization step in the present invention include organic peroxide-based initiators. Examples of the organic peroxide-based initiator include the following. Benzoyl peroxide, methyl ethyl ketone peroxide, diisopropyl peroxy carbonate, cumene hydroperoxide, 2,4-dichlorobenzoyl peroxide, lauroyl peroxide, tert-butyl-peroxypivarate, tert-hexyl-peroxypivalate, di-tert-butyl-per Oxide, tert-butyl-peroxy-2-ethylhexanoate, tert-butyl-hydroperoxide, tert-butyl-peroxyacetate, tert-hexyl-peroxy-isopropyl carbonate, tert-butyl-peroxy-2-ethylhexyl carbonate , Dibenzoyl-peroxide, tert-amyl-peroxy-2-ethylhexanoate, tert-butyl-peroxyisobutyrate, 1,1-di (tert-amylperoxy) -cyclohexane, tert-amyl-peroxy- Isononanoate, tert-amyl-peroxy-normal octoate, 1,1-di (tert-butylperoxy) -cyclohexane, tert-amyl-peroxy-isopropyl carbonate, tert-butyl-peroxy-isopropyl carbonate, tert-amyl -Peroxy-2-ethylhexyl carbonate, tert-amyl-peroxybenzoate, tert-amyl-peroxyacetate, tert-butyl-peroxyisononanoate, tert-butyl-peroxybenzoate, 2,2-di (tert-) Butyl peroxide) -butane, n-butyl-4,4-di (tert-butyl peroxide) -valerate, ethyl-3,3-di (tert-butyl peroxide) -butylate, 1,3-di (2) -Tert-Butylperoxyisopropyl) -benzene, dicumyl-peroxide, 2,5-dimethyl-2,5-di (tert-butylperoxy) -hexane, di-tert-amyl-peroxide, 1,1, 3,3,-Tetramethylbutyl-hydroperoxide, 2,5-dimethyl-2,5-di (tert-butylperoxy) -hexin-3.

The polymerization initiator A, which is present from the beginning in the polymerization step, is contained in the particles of the polymerizable monomer composition and increases the conversion rate of the polymerizable monomer to 90.0% or more, and is halved for 10 hours. It is selected by comprehensively considering the period temperature and the properties of decomposition products. Generally, the amount of the polymerization initiator added is 0.5 parts by mass or more and 20 parts by mass or less with respect to 100 parts by mass of the polymerizable monomer.

In the present invention, the polymerization initiator B added when the conversion rate of the polymerizable monomer contained in the particles of the polymerizable monomer composition is 90% or more includes, for example, the following water-soluble polymerization initiator. Can be mentioned. Persulfates such as potassium persulfate, sodium persulfate, ammonium persulfate (sulfates are produced as ionic residues), perphosphates such as potassium perphosphate (similarly, phosphate ions are produced). , Percarbonates such as potassium persulfate (similarly, carbonate ions are generated), hydrogen peroxide, water-soluble azo polymerization initiators such as 2,2'-azobis (2-methylpropionamidine) and dihydrochloride (similarly) In addition, organic ammonium ions are generated).

In the present invention, the amount of the polymerization initiator B added when the conversion rate of the polymerizable monomer contained in the particles of the polymerizable monomer composition is 90.0% or more is generally polymerizable. 0.05 parts by mass or more and 10 parts by mass or less are used with respect to 100 parts by mass of the monomer.

(External agent)
An external additive can be added to the toner particles obtained by the production method of the present invention for the purpose of improving various powder properties. Examples of the external additive include the following. Metal oxides such as aluminum oxide, titanium oxide, strontium titanate, cerium oxide, magnesium oxide, tin oxide, zinc oxide; nitrides such as silicon nitride; carbides such as silicon carbide; oxides such as silicon oxide; calcium sulfate, Inorganic metal salts such as barium sulfate and calcium carbonate; fatty acid metal salts such as zinc stearate and calcium stearate; carbon black, silica.

As these external additives, 0.01 parts by mass or more and 10 parts by mass or less are used with respect to 100 parts by mass of the toner particles, and preferably 0.05 parts by mass or more and 5 parts by mass or less are used. These external additives may be used alone or in combination.

Further, these external additives are more preferably hydrophobized.

Various measuring methods of toner particles obtained by the suspension polymerization method will be described below.

<Aspect ratio measurement method>
The aspect ratio of the toner particles was measured by a flow-type particle image analyzer "FPIA-3000" (manufactured by Sysmex) under the measurement and analysis conditions during the calibration work.

The specific measurement method is as follows. First, about 20 ml of ion-exchanged water from which impure solids and the like have been removed in advance is placed in a glass container. Among them, as a dispersant, "Contaminone N" (a 10% by mass aqueous solution of a neutral detergent for cleaning a precision measuring instrument with a pH of 7 consisting of a nonionic surfactant, an anionic surfactant, and an organic builder, manufactured by Wako Pure Chemical Industries, Ltd. ) Is diluted about 3 times by mass with ion-exchanged water, and about 0.2 ml of the diluted solution is added. Further, about 0.02 g of the measurement sample is added, and the dispersion treatment is performed for 2 minutes using an ultrasonic disperser to prepare a dispersion liquid for measurement. At that time, the dispersion is appropriately cooled so that the temperature of the dispersion is 10 ° C. or higher and 40 ° C. or lower. As the ultrasonic disperser, a desktop ultrasonic cleaner disperser (for example, "VS-150" (manufactured by Vervocrea)) having an oscillation frequency of 50 kHz and an electrical output of 150 W is used, and a predetermined amount is contained in the water tank. Ion-exchanged water is added, and about 2 ml of the contaminanton N is added into the water tank.

For the measurement, the flow type particle image analyzer equipped with "LUCPLFLN" (magnification 20 times, numerical aperture 0.40) was used as the objective lens, and the particle sheath "PSE-900A" (manufactured by Sysmex) was used as the sheath liquid. It was used. The dispersion prepared according to the above procedure is introduced into the flow type particle image analyzer, and 2000 toner particles are measured in the total count mode in the HPF measurement mode. The aspect ratio was calculated by limiting the diameter of the analyzed particle to the equivalent circle diameter (number) and limiting it to 4.044 μm or more and less than 100.0 μm.

In the measurement, automatic focus adjustment is performed using standard latex particles (for example, "RESAARCH AND TEST PARTICLES Latex Microsphere Suspensions 5100A" manufactured by Duke Scientific Co., Ltd. diluted with ion-exchanged water) before the start of the measurement. After that, it is preferable to perform focus adjustment every 2 hours from the start of measurement.

In the embodiment of the present application, a flow-type particle image analyzer for which a calibration work was performed by Sysmex Corporation and a calibration certificate issued by Sysmex Corporation was issued was used. The measurement was performed under the measurement and analysis conditions at the time of receiving the calibration certificate, except that the diameter of the analysis particle was limited to the equivalent circle diameter (number) of 4.044 μm or more and less than 100.0 μm.

<Measuring method of volume-based median diameter (Dv50) and number-based median diameter (Dn50)>
The volume-based median diameter (Dv50) and the number-based median diameter (Dn50) of the toner particles are calculated as follows. As the measuring device, a precision particle size distribution measuring device "Coulter Counter Multisizer 3" (registered trademark, manufactured by Beckman Coulter) equipped with a 100 μm aperture tube by the pore electrical resistance method is used. For the setting of measurement conditions and the analysis of measurement data, the attached dedicated software "Beckman Coulter Multisizer 3 Version 3.51" (manufactured by Beckman Coulter) is used. The measurement is performed with 25,000 effective measurement channels.

As the electrolytic aqueous solution used for the measurement, a special grade sodium chloride dissolved in ion-exchanged water so as to have a concentration of about 1% by mass, for example, "ISOTON II" (manufactured by Beckman Coulter) can be used.

Before performing the measurement and analysis, the dedicated software was set as follows.

On the "Change standard measurement method (SOMME)" screen of the dedicated software, set the total count number in the control mode to 50,000 particles, measure once, and set the Kd value to "standard particles 10.0 μm" (Beckman Coulter). Set the value obtained using (manufactured by the company). By pressing the "threshold / noise level measurement button", the threshold and noise level are automatically set. Also, set the current to 1600 μA, the gain to 2, and the electrolyte to ISOTON II, and check “Flash of aperture tube after measurement”.

On the "Pulse to particle size conversion setting" screen of the dedicated software, the bin spacing is set to logarithmic particle size, the particle size bin is set to 256 particle size bins, and the particle size range is set from 2 μm to 60 μm.

The specific measurement method is as follows.
(1) Approximately 200 ml of the electrolytic aqueous solution is placed in a glass 250 ml round bottom beaker dedicated to Multisizer 3 and set on a sample stand, and the stirrer rod is stirred counterclockwise at 24 rpm. Then, the dirt and air bubbles in the aperture tube are removed by the "aperture flash" function of the dedicated software.
(2) Put about 30 ml of the electrolytic aqueous solution in a 100 ml flat bottom beaker made of glass. Among them, as a dispersant, "Contaminone N" (a 10% by mass aqueous solution of a neutral detergent for cleaning a precision measuring instrument with a pH of 7 consisting of a nonionic surfactant, an anionic surfactant, and an organic builder, manufactured by Wako Pure Chemical Industries, Ltd. ) Is diluted about 3 times by mass with ion-exchanged water, and about 0.3 ml of the diluted solution is added.
(3) Two oscillators with an oscillation frequency of 50 kHz are built in with their phases shifted by 180 degrees, and an ultrasonic disperser "Ultrasonic Dispersion System Tera150" (manufactured by Nikkaki Bios) with an electrical output of 120 W is prepared. Approximately 3.3 liters of ion-exchanged water is placed in the water tank of the ultrasonic disperser, and about 2 ml of contaminantinon N is added into the water tank.
(4) The beaker of (2) is set in the beaker fixing hole of the ultrasonic disperser, and the ultrasonic disperser is operated. Then, the height position of the beaker is adjusted so that the resonance state of the liquid level of the electrolytic aqueous solution in the beaker is maximized.
(5) With the electrolytic aqueous solution in the beaker of (4) irradiated with ultrasonic waves, about 10 mg of toner is added little by little to the electrolytic aqueous solution and dispersed. Then, the ultrasonic dispersion processing is continued for another 60 seconds. In ultrasonic dispersion, the water temperature in the water tank is appropriately adjusted to be 10 ° C. or higher and 40 ° C. or lower.
(6) Using a pipette, the aqueous electrolyte solution of (5) in which toner is dispersed is dropped onto the round-bottom beaker of (1) installed in the sample stand, and the measured concentration is adjusted to about 5%. .. Then, the measurement is performed until the number of measurement particles reaches 50,000.
(7) The measurement data is analyzed by the dedicated software attached to the device, and the volume-based median diameter (Dv50) and the number-based median diameter (Dn50) are calculated. The closer the ratio of Dv50 to Dn50 (Dv50 / Dn50) is, the sharper the particle size distribution.

<Measurement method for organic volatile substances>
(1) The materials used for the measurement were adjusted according to the following procedure.

Hydrochloric acid is added to a dispersion of about 100 ml of toner particles to bring the pH to 1.4 or less, and the treatment solution is placed in a pressure filter to perform filtration. After filtration, 200 ml of water was added to the pressure filter, and the mixture was filtered again and washed. After performing the washing operation twice, the pressure inside the pressure filter is set to 0.2 MPa and pressed for 10 minutes to obtain a cake of toner particles. The cake of toner particles after filtration is crushed and dried at room temperature for 18 hours to obtain toner particles.

The amount of organic volatile substances in toluene equivalent to toner can be quantified by the headspace method as follows.

300 mg of toner particles are precisely weighed in a headspace vial (volume 22 ml), and sealed with a crimp cap and a special septum coated with fluororesin using a crimper. This vial is set in a headspace sampler and gas chromatogram (GC) analysis is performed under the following conditions. Then, the total area value of the peaks of the obtained GC chart is calculated by data processing. At this time, an empty vial not filled with toner particles is also measured as a blank at the same time, and the measured value in the blank measurement is subtracted from the toner measurement data.

On the other hand, prepare several points (for example, 0.1 μl, 0.5 μl, 1.0 μl) in which only toluene is precisely weighed in the vial, and measure each of them under the following analysis conditions before measuring the toner particle sample. After that, a calibration curve is prepared from the amount of toluene charged and the toluene area value.

The amount of organic volatile substance in terms of toluene can be obtained by converting the area value of the organic volatile substance of the toner into the mass of toluene based on this calibration curve, and further converting it into the amount based on the mass of the toner.

(2) Measuring device and measuring conditions Headspace sampler: HEWLETT PACKARD 7649
Oven temperature: 150 ° C
Sample heating time: 60 minutes Sample loop (Ni): 1 ml
Loop temperature: 170 ° C
Transfer line temperature: 190 ° C
Pressurization time: 0.50 minutes LOOP FILL TIME: 0.01 minutes LOOP EQ TIME: 0.06 minutes INJECT TIME: 1.00 minutes GC cycle time: 80 minutes Carrier gas: He
GC: HEWLETT PACKARD 6890GC (detector: FID)
Column: HP-1 (inner diameter 0.25 μm x 30 m)
Oven: (1) 35 ° C: 20 minutes hold, (2) 20 ° C / min temperature rise to 300 ° C 20 minutes hold INJ: 300 ° C, splitless, constant pressure (20psi) mode DET: 320 ° C

<Measurement method of adsorption amount of poorly water-soluble inorganic fine particles>
The measurement of fluorescent X-rays of each element conforms to JIS K 0119-1969, but the specifics are as follows.

As the measuring device, the wavelength dispersive fluorescent X-ray analyzer "Axios" (manufactured by PANalytical) and the attached dedicated software "SuperQ ver. 4.0F" (manufactured by PANalytical) for setting the measurement conditions and analyzing the measurement data. ) Is used. Rh is used as the anode of the X-ray tube, the measurement atmosphere is vacuum, the measurement diameter (collimator mask diameter) is 27 mm, and the measurement time is 10 seconds. Further, when measuring a light element, it is detected by a proportional counter (PC), and when measuring a heavy element, it is detected by a scintillation counter (SC).

As a measurement sample, put about 4 g of toner in a dedicated press aluminum ring, flatten it, and use a tablet molding compressor "BRE-32" (manufactured by Maekawa Testing Machine Mfg. Co., Ltd.) at 20 MPa for 60. Pressurize for seconds and use pellets molded to a thickness of about 2 mm and a diameter of about 39 mm.

Measurement is performed under the above conditions, an element is identified based on the obtained peak position of X-rays, and the concentration is calculated from the counting rate (unit: cps) which is the number of X-ray photons per unit time.

First, poorly water-soluble inorganic fine particles are added to 100 parts by mass of toner particles so as to be 0.10 parts by mass, and the mixture is sufficiently mixed using a coffee mill. Similarly, the poorly water-soluble inorganic fine particles are mixed with the toner particles so as to be 0.20 parts by mass and 0.50 parts by mass, respectively, and these are used as a sample for the calibration curve.

For each sample, pellets of the sample for the calibration curve are prepared as described above using a tablet molding compressor, and the counting rate (unit: cps) of the element derived from the poorly water-soluble inorganic fine particles is measured. A calibration curve having a linear function is obtained with the obtained X-ray count rate on the vertical axis and the amount of poorly water-soluble inorganic fine particles added to each calibration curve sample on the horizontal axis.

Next, the toner to be analyzed is pelletized as described above using a tablet molding compressor, and the counting rate is measured in the same manner. Then, the amount of poorly water-soluble inorganic fine particles adsorbed by the toner is determined from the above calibration curve.

<Measurement method of zeta potential value of poorly water-soluble inorganic fine particles>
For the measurement of the zeta potential value (ζ) of the poorly water-soluble inorganic fine particles in the present invention, Zetasizer Nano ZS (manufactured by MALVERN) and the attached dedicated software “Dispersion Technology software 4.” for setting measurement conditions and analyzing measurement data. 20 ”(manufactured by MALVERN) was used for calculation. The specific measurement method is as follows.

(1) After the preparation of the aqueous medium containing the poorly water-soluble inorganic fine particles was completed, a part of the aqueous medium was withdrawn from the container and transferred to a syringe having a volume of 10 ml. Next, insert the tip of the syringe into one sample port of the zeta potential measurement capillary cell (DTS1060-Clear disposable zeta cell) that was co-washed with ion-exchanged water twice, and slowly pour the aqueous medium so that no bubbles are generated. It is. After confirming that the liquid was injected into the capillary part without any gaps, the two sample ports were plugged.

(2) The cell was inserted into the cell holder of the measuring device, and the lid of the detection unit was closed. The measurement was performed under the following measurement conditions.
F (ka) selection Model: Smoluchowski
Dispersant: Water
Temperature: Temperature during granulation (usually 50 ° C to 70 ° C)
Result Calculation: General Purpose

(3) After the measurement was completed, the value of "Zeta Potential" was set as the average value of the zeta potential values on the displayed measurement result report screen.

The present invention will be specifically described with reference to the following examples.

[Example 1]
Toner was manufactured by the following procedure.

25.0 parts by mass of sodium phosphate and 10.0 parts by mass of 10% hydrochloric acid were added to 1000 parts by mass of ion-exchanged water in the reaction vessel, and the mixture was kept warm at 60 ° C. for 60 minutes while purging N ₂ . T. K. Using a homomixer (manufactured by Tokushu Kagaku Kogyo), while stirring at 12000 rpm, a calcium chloride aqueous solution in which 16.0 parts by mass of calcium chloride is dissolved is added to 10 parts by mass of ion-exchanged water, and an aqueous system containing a dispersion stabilizer is added. The medium was prepared. The zeta potential value of the obtained aqueous medium at 60 ° C. was measured.
-Styrene 48 parts by mass-Colorant (CI Pigment Red 122 / CI Pigment Red 57 = 1/1)
7 parts by mass, charge control agent (Orient: Bontron E-88) 0.40 parts by mass Next, the above material was put into an attritor disperser (Mitsui Miike Machinery Co., Ltd.), and zirconia particles with a diameter of 1.7 mm were used. The mixture was dispersed at 220 rpm for 5 hours.

To this dispersion: 16 parts by mass of styrene, 20 parts by mass of n-butyl acrylate, amorphous polyester resin (Mw = 10000, acid value = 10.0 mgKOH / g)
2.5 parts by mass, wax (manufactured by Nippon Seiro Co., Ltd., product name = "paraffin wax 135", melting point = 58 ° C)
12 parts by mass was added.

The above material was kept at 63 ° C. in a separate container, and T.I. K. Using a homomixer (manufactured by Tokushu Kagaku Kogyo), it was uniformly dissolved and dispersed at 500 rpm. To this, tert-butyl-peroxypivalate (manufactured by Nippon Oil & Fats Co., Ltd., trade name "perbutyl PV", 10-hour half-life temperature: 55 ° C.): 2.0 parts by mass, which is an organic peroxide-based initiator, is dissolved. Then, a polymerizable monomer composition was prepared.

The polymerizable monomer composition was charged into the aqueous medium, 60 ° C., the N ₂ purge under, T. K. Granulation was performed by stirring with a homomixer at 10000 rpm for 5 minutes. Then, the temperature is raised to 67 ° C. while stirring with a paddle stirring blade, and the water-soluble polymerization initiator is obtained when the conversion rate of the polymerizable monomer contained in the particles of the polymerizable monomer composition is 98.1%. An aqueous solution prepared by dissolving 0.5 parts by mass of potassium persulfate in 19.5 parts by mass of distilled water was added dropwise. At the same time as potassium persulfate, an aqueous solution prepared by dissolving 0.15 parts by mass of sodium carbonate in 3.0 parts by mass of distilled water as a pH adjuster was added dropwise and maintained at 67 ° C. The reaction at 67 ° C. was carried out for a total of 5 hours. Next, the temperature of the dispersion was raised to 85 ° C., and the reaction was carried out for 10 minutes.

Then, this dispersion was polymerized using the organic volatile substance removing apparatus shown in FIG. The specific procedure is as follows.

The dispersion was transferred to the evaporation vessel 2, and the temperature was raised to 95 ° C. while stirring with the stirring blade 10. After that, the bottom valve 11 of the evaporation vessel was opened, gas was sent from the gas blowing line 12, and gas was blown from the blowing nozzle (6 in FIG. 2) of the ejector 4. The gas blown at this time was water vapor, and the gas having a water vapor pressure of 0.42 MPa and a temperature of 100 ° C. was used. The back pressure valve 14 was throttled so that the temperature of the dispersion liquid when circulating in the external circulation path became 116.0 ° C., and the organic volatile substance removal step was performed for 5 hours. The blowing flow rate was 80 kg / hr. The circulating flow rate of the dispersion liquid at this time was 7 l / min.

After cooling the dispersion liquid that had undergone the organic volatile substance removing step, hydrochloric acid was added to adjust the pH to 1.4, and the mixture was stirred for 2 hours. Then, after filtering and washing with water, it was dried at a temperature of 40 ° C. for 48 hours to obtain toner 1.

With respect to the toner 1 thus obtained, the concentration of organic volatile substances was measured. Further, in order to evaluate the degree of contamination of the deposits and the degree of coalescence of the toners, the median diameter (Dv50), Dv50 / Dn50 and the aspect ratio based on the volume of the toner 1 were measured.

[Example 2]
Toner 2 was added under the same conditions and methods as in Example 1 except that the conversion rate of the polymerizable monomer contained in the particles of the polymerizable monomer composition when potassium persulfate was added was 91.7%. Obtained.

[Example 3]
Toner 3 was added under the same conditions and methods as in Example 1 except that the conversion rate of the polymerizable monomer contained in the particles of the polymerizable monomer composition when potassium persulfate was added was 99.8%. Obtained.

[Example 4]
Toner 4 was obtained under the same conditions and methods as in Example 1 except that potassium persulfate was replaced with sodium persulfate.

[Example 5]
Toner 5 was obtained under the same conditions and methods as in Example 1 except that potassium persulfate was replaced with ammonium persulfate.

[Example 6]
Toner 6 was obtained under the same conditions and methods as in Example 1 except that the amount of sodium phosphate added when preparing the aqueous medium containing the dispersion stabilizer was changed to 28.5 parts by mass.

[Example 7]
Toner 7 was obtained under the same conditions and methods as in Example 1 except that the amount of sodium phosphate added when preparing the aqueous medium containing the dispersion stabilizer was changed to 21.0 parts by mass.

[Example 8]
Same as Example 1 except that tert-butyl-peroxypivalate was replaced with tert-hexyl-peroxypivalate (manufactured by NOF CORPORATION, trade name "perhexyl PV", 10-hour half-life temperature: 53 ° C.). Toner 8 was obtained according to the conditions and methods.

[Example 9]
tert-Butyl-peroxypivalate 1,1,3,3-tetramethylbutyl-peroxy-2-ethylhexanoate (manufactured by NOF CORPORATION, trade name "Perocta O", 10-hour half-life temperature: 65 ° C. ) Was used to obtain the toner 9 under the same conditions and methods as in Example 1.

[Example 10]
In the organic volatile substance removing step, the toner 10 was obtained under the same conditions and methods as in Example 1 except that the temperature of the dispersion liquid when circulating in the external circulation path was set to 103.4 ° C.

[Example 11]
In the organic volatile substance removing step, the toner 11 was obtained under the same conditions and methods as in Example 1 except that the temperature of the dispersion liquid when circulating in the external circulation path was set to 156.5 ° C.

[Example 12]
Toner 12 was obtained under the same conditions and methods as in Example 1 except that potassium persulfate was replaced with potassium perphosphate.

[Example 13]
Toner 13 was obtained under the same conditions and methods as in Example 1 except that potassium persulfate was replaced with potassium percarbonate.

[Example 14]
The amount of sodium phosphate added when preparing an aqueous medium containing a dispersion stabilizer was changed to 30.0 parts by mass, and potassium persulfate was changed to 2,2'-azobis (2-methylpropionamidine) and dihydrochloric acid (sum). Toner 14 was obtained under the same conditions and methods as in Example 1 except that the toner was replaced with "V-50" manufactured by Kojun Yakuhin Kogyo Co., Ltd., with a 10-hour half-life temperature: 56 ° C.

[Example 15]
Toner 15 was obtained under the same conditions and methods as in Example 1 except that the amount of sodium phosphate added when preparing the aqueous medium containing the dispersion stabilizer was changed to 19.5 parts by mass.

[Example 16]
In the organic volatile substance removing step, the toner 16 was obtained under the same conditions and methods as in Example 1 except that the temperature of the dispersion liquid when circulating in the external circulation path was set to 97.8 ° C.

[Example 17]
In the organic volatile substance removing step, the toner 17 was obtained under the same conditions and methods as in Example 1 except that the liquid temperature of the dispersion liquid when circulating in the external circulation path was 163.7 ° C.

[Comparative Example 1]
The experiment was carried out under the same conditions and methods as in Example 1 except that the organic volatile substance removing device shown in FIG. 3 was used for circulation by a pump instead of the organic volatile substance removing device shown in FIG. However, the experiment was stopped because no circulation was performed in the organic volatile substance removal step. When the external circulation path was confirmed, deposits were confirmed near the pump.

[Comparative Example 2]
The same conditions and methods as in Example 1 except that the organic volatile substance removing device shown in FIG. 4 was used instead of the organic volatile substance removing device shown in FIG. 1 to perform the organic volatile substance removing step at 99.7 ° C. Toner 18 was obtained.

[Comparative Example 3]
Toner 19 was added under the same conditions and methods as in Comparative Example 2 except that the conversion rate of the polymerizable monomer contained in the particles of the polymerizable monomer composition when potassium persulfate was added was 88.2%. Obtained.

[Comparative Example 4]
Toner 20 was obtained under the same conditions and methods as in Comparative Example 2 except that the amount of sodium phosphate added when preparing the aqueous medium containing the dispersion stabilizer was changed to 35.0 parts by mass.

[Comparative Example 5]
Toner 21 was obtained under the same conditions and methods as in Comparative Example 2 except that potassium persulfate was replaced with V-50.

Table 1 shows the toner production conditions and the like in the above Examples and Comparative Examples. Table 2 shows the measurement results of the volume-based median diameter (Dv50), Dv50 / Dn50, aspect ratio, and organic volatile substance concentration of the obtained toner particles.

The evaluation of the concentration of organic volatile substances was based on the following criteria.
A: Less than 8.0 ppm B: 8.0 ppm or more and less than 16.0 ppm C: 16.0 ppm or more and less than 24.0 ppm D: 24.0 ppm or more

The evaluation of Dv50 / Dn50 was based on the following criteria.
A: less than 1.20 B: 1.20 or more and less than 1.30 C: 1.30 or more

The aspect ratio was evaluated based on the following criteria.
A: 0.960 or more B: 0.900 or more and less than 0.960 C: less than 0.900

Further, in each Example and Comparative Example, the fluorescent X-ray measurement of the toner obtained by filtering and drying the dispersion liquid after the organic volatile substance removal step was performed, and the amount of the poorly water-soluble inorganic fine particles adsorbed on the toner was calculated. .. As a result, the toner 15 adsorbed the most poorly water-soluble inorganic fine particles. In addition, the toner 1 to the toner 11 and the toner 16 to the toner 19 adsorbed the least water-soluble inorganic fine particles. Further, the toner 12 to the toner 14 adsorbed the poorly water-soluble inorganic fine particles in the second largest amount. The toner 20 and the toner 21 adsorbed the least amount of the poorly water-soluble inorganic fine particles. It is presumed that the mechanism that resulted in such a result is as described above.

1: Organic volatile substance remover, 2: Evaporation vessel, 3: External circulation path, 4: Ejector, 5: Casing, 6: Blow nozzle, 7: Discharge nozzle, 8: Pump, 9: Suction port, 10: Stirring blade , 11: Evaporation vessel bottom valve, 12: Gas blowing line, 13: Gas blowing port, 14: Back pressure valve, 15: Return port

Claims (7)

Preparation process for preparing an aqueous medium containing poorly water-soluble inorganic fine particles,
A granulation step of forming particles of a polymerizable monomer composition containing a polymerizable monomer in the aqueous medium, and
A polymerization step of polymerizing the polymerizable monomer contained in the particles of the polymerizable monomer composition to obtain resin particles,
A method for producing resin particles, which comprises an organic volatile substance removing step of removing an organic volatile substance from the resin particles.
In the polymerization step, a polymerization initiator is added when the conversion rate of the polymerizable monomer contained in the particles of the polymerizable monomer composition is 90.0% or more.
The polarity of the ionic residue derived from the polymerization initiator and the polarity of the poorly water-soluble inorganic fine particles are opposite.
In the organic volatile substance removal step, an evaporation container and an organic volatile substance removal device having an external circulation path connected to the evaporation container are used.
An ejector is provided in the external circulation path.
The ejector is
(I) Casing and
(Ii) A blowing nozzle that blows gas into the casing,
(Iii) A suction port for sucking the liquid discharged from the evaporation container into the casing by the action of the gas blown into the casing.
(Iv) A discharge nozzle for discharging the liquid and the gas from the casing to the external circulation path, and
A method for producing resin particles, which comprises the above. The method for producing resin particles according to claim 1, wherein the polarity of the ionic residue derived from the polymerization initiator is negative. The method for producing resin particles according to claim 1 or 2, wherein the polymerization initiator is a persulfate compound. When the average value of the zeta potential values of the poorly water-soluble inorganic fine particles is ζ,
0.0mV <ζ≤20.0mV
The method for producing resin particles according to any one of claims 1 to 3. Any of claims 1 to 4 which increases the conversion rate of the polymerizable monomer contained in the particles of the polymerizable monomer composition by 90.0% or more by polymerizing with a polymerization initiator. The method for producing resin particles according to item 1. When the temperature at which the aqueous medium containing the resin particles circulates in the external circulation path is T.
100.0 ° C ≤ T ≤ 160.0 ° C
The method for producing resin particles according to any one of claims 1 to 5. The method for producing resin particles according to any one of claims 1 to 6, wherein the resin particles are toner particles.

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