JP2017171786A - Method for producing resin particle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing resin particles using an organic volatile material moving device which has a high reduction efficiency of an organic volatile substance and has little adhesion to a device.SOLUTION: There is provided a method for producing resin particles which includes a polymerization step of polymerizing a polymerizable monomer contained in particles of a polymerizable monomer composition, where the polymerization step has a first polymerization step of performing polymerization using a first polymerization initiator and a second polymerization step of performing polymerization using a second polymerization initiator, 10 hr half-line temperatures of the first and second polymerization initiators are represented by T1(°C) and T2(°C) and polymerization temperatures of the first and second polymerization steps are represented by t1(°C) and t2(°C), the following expressions of T1+5≤t1≤T1+20, T2-60≤t1≤T2, T2-30≤t2≤T2+80, T1<T2 and t1<t2 are satisfied, and the second polymerization step is a step of polymerizing the polymerizable monomer inside of an external circulation path 3 connected to a polymerization container 2.SELECTED DRAWING: Figure 1

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 a standard value for the amount of organic volatile substances in chemical products. In order to comply with such environmental standards, proposals regarding the removal of organic volatile substances in chemical products have been actively made.
In Patent Document 1, a processing liquid containing an organic volatile substance is circulated through a circulation system in which an evaporation vessel is incorporated, water vapor is introduced into the circulation path, and the organic volatile substance is removed by dispersing and discharging the processing liquid. A method is disclosed. Patent Document 2 discloses an organic volatile substance removing method in which a processing liquid extracted from an evaporation container is heated by a heating device provided in a circulation path, and the heated processing liquid is returned to the evaporation container.
Although these methods can remove organic volatile substances, their effects are limited. For example, 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 and heating device that circulates the processing liquid, reducing the efficiency of removing volatile substances and reducing the productivity, for example, the device must be stopped to remove the adhesion. There was a problem of letting it go.
Organic volatile substances are also used in wet toner particle manufacturing 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. There have been many proposals regarding the removal of odors. When a large amount of organic volatile substances such as a polymerizable monomer and a by-product are present in the toner particles, the fluidity of the toner may be lowered to worsen the working environment or generate an unpleasant odor. Particularly in recent years, interest in the environment has been increasing, and it is required to reduce the volatile components derived from toner particles generated in the heat and pressure fixing device.
In Patent Document 3, the evaporation container and the external circulation path are depressurized, the dispersion liquid of particles is extracted from the evaporation container to the external circulation path, heated in an external heat exchanger and returned to the evaporation container to remove organic volatile substances. A method of performing is disclosed. Although it is possible to reduce the organic volatile matter in the particles by this method, the effect is limited because the amount of heat given is small, and it is difficult to fully respond to the recent demand for removing organic volatile matter. is there. In addition, particles adhere to the pump and heating device that circulates the processing liquid, reducing the efficiency of removing organic volatile substances, and reducing the productivity, such as having to stop the device to remove the adhesion. In some cases, it may be allowed to.
In Patent Document 4, a dispersion of particles in an evaporation container 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 that remove organic volatile substances. A method is disclosed. In this method, although the removal efficiency of organic volatile substances is remarkably improved as compared with the conventional method, it is difficult to sufficiently cope with the recent demand for removing organic volatile substances. In addition, since the pump is used for circulating the processing liquid, the problem of adhesion of particles to the pump remains.
Although it is different from the removal of organic volatile substances from chemical products, there is Patent Document 5 as a method for distilling the cleaning liquid. In Patent Document 5, as a method of distilling and regenerating the cleaning liquid, a method is disclosed in which the cleaning liquid in the evaporation container is sent to an external circulation path and passed through an ejector incorporated in the external circulation path. In this method, after the gas is drawn into the ejector to bring it into a pressurized state, the pressure is released by returning the pressurized cleaning liquid to the evaporation vessel, and the organic volatile substances in the cleaning liquid are evaporated using this pressure change to distill. It is carried out.
This method can evaporate organic volatile substances in the liquid, but has a limited effect when removing organic volatile substances in chemical products. Moreover, since the pump is used for sending 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 clogged pump, use of an ejector without a mechanical operation unit can be considered. However, since the performance of the ejector is determined by the shape and the shape cannot be changed after manufacturing, it is necessary to design the shape appropriately for the processing solution.
The above is a technique for reducing organic volatile substances by a manufacturing method, but there is also a technique for reducing organic volatile substances by additives. In Patent Document 6, two types of polymerization initiators are added, and organic volatile substances in the binder resin for toner are reduced by passing through a two-step process having different reaction temperatures. In the second step, the entire 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, since the entire reaction system is pressurized in the second stage process, 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.

Japanese Patent No. 4866378 JP-A-5-194624 Japanese Patent No. 4092528 Japanese Patent No. 5376959 JP 2004-105845 A JP 2000-172010 A

  This invention is providing the manufacturing method of the resin particle which solved the above problems. That is, this invention is providing the manufacturing method of the resin particle using the organic volatile substance removal apparatus with high reduction efficiency of an organic volatile substance, and few adhesion to an apparatus.

The inventors of the present invention have made extensive studies on the reduction of organic volatile substances and the suppression of the adherence of processed materials to the apparatus, and as a result, have found the following resin particle production method.
That is, a granulation step of forming particles of a polymerizable monomer composition containing a polymerizable monomer in an aqueous medium, and a polymerization of the polymerizable monomer contained in the particles of the polymerizable monomer composition A polymerization step, wherein the polymerization step is performed after the first polymerization step using the first polymerization initiator, and the second polymerization initiator. A first polymerization step, wherein the first polymerization initiator has a 10-hour half-life temperature of T1 (° C.), and the second polymerization initiator has a 10-hour half-life temperature. Is a step in which polymerization is performed at a temperature t1 (° C.) satisfying the following relationship:
T1 + 5 ≦ t1 ≦ T1 + 20
T2-60 ≦ t1 ≦ T2
The second polymerization step is a step in which polymerization is performed at a temperature t2 (° C.) that satisfies the following relationship:
T2-30 ≦ t2 ≦ T2 + 80
The second polymerization step is a step of polymerizing inside the external circulation path connected to the polymerization vessel, the external circulation path is provided with an ejector, the ejector,
(I) a casing;
(Ii) a blowing nozzle for blowing gas into the casing;
(Iii) a suction port for sucking the liquid discharged from the polymerization container into the casing by the action of the gas blown into the casing;
(Iv) a discharge nozzle for discharging liquid and gas from the casing to the external circulation path;
It is a manufacturing method of the resin particle characterized by having.
Moreover, the polymerization temperature of a 2nd polymerization process is 100 to 150 degreeC, It is a manufacturing method of the resin particle characterized by the above-mentioned.

  ADVANTAGE OF THE INVENTION According to this invention, the reduction efficiency of an organic volatile substance is high, and the manufacturing method of the resin particle with few adhesion to an apparatus can be provided.

It is the schematic which shows an example of the organic volatile substance removal apparatus which can be applied to this invention. It is a schematic diagram of an ejector applicable to the present 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.

  As an example, the case where the present invention is used in a toner production method by a suspension polymerization method will be described below.

  The suspension polymerization method is a method in which particles of a polymerizable monomer composition containing a polymerizable monomer and a colorant are formed in an aqueous medium, and a polymerizable monomer contained in the particles of the polymerizable monomer composition is formed. In this method, toner particles are obtained by polymerizing a monomer.

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

(Polymerizable monomer composition preparation process)
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 another composition, or may be dispersed after mixing all the compositions.

(Granulation process)
The polymerizable monomer composition is put into an aqueous medium containing an inorganic dispersion stabilizer and dispersed to obtain granules, thereby obtaining a polymerizable monomer composition dispersion. The granulation step can be performed, for example, in a vertical stirring tank provided with a stirrer having a high shearing force. Although it does not specifically limit as a stirrer which has high shear force, For example, a high shear mixer (made by IKA), T.C. K. Homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.) K. Commercially available products such as Philmix (manufactured by Special Machine Engineering Co., Ltd.) and Claremix (manufactured by M Technique Co., Ltd.) can be used.

  Examples of the inorganic dispersion stabilizer include, for example, 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, sulfuric acid Examples thereof include sulfates such as calcium; metal hydroxides of calcium hydroxide, aluminum hydroxide, magnesium hydroxide, and ferric hydroxide; These can be used alone or in combination of two or more. These exhibit functions as a dispersion stabilizer by being present as fine particles in an aqueous medium.

(First polymerization step)
A polymerization initiator is added to the polymerizable monomer composition dispersion obtained as described above to polymerize the polymerizable monomer. In the polymerization step in the present invention, a general stirring tank capable of adjusting the temperature can be used. The polymerization temperature is 40 ° C. or higher, generally 50 to 90 ° C. Any stirring blade may be used as long as it can float the polymerizable monomer composition dispersion without stagnation and keep the temperature in the tank uniform. As stirring blades or stirring means, paddle blades, inclined paddle blades, three retreat blades, propeller blades, disk turbine blades, helical ribbon blades and anchor blades such as anchor blades, and “full zone” (Shinko Pantech) , “Twin Star” (manufactured by Shinko Pantech Co., Ltd.), “Max Blend” (manufactured by Sumitomo Heavy Industries, Ltd.), “Super Mix” (manufactured by Satake Chemical Machinery Co., Ltd.), and “Hi-F Mixer” (Soken Chemical Co., Ltd.) Manufactured).

  The polymerization temperature in the second polymerization step is set higher than the polymerization temperature in the first polymerization step. Further, the 10-hour half-life temperature of the second polymerization initiator is set higher than the 10-hour half-life temperature of the first polymerization initiator. The first polymerization initiator having a low 10-hour half-life temperature is largely decomposed in the first polymerization step to form a toner binder. The second polymerization initiator having a high 10-hour half-life temperature remains almost undecomposed in the first polymerization step and is largely decomposed in the second polymerization step, so that the unreacted polymerizable monomer remaining in the dispersion liquid The body can be reduced. In addition, the polymerization temperature in the first polymerization step and the polymerization temperature in the second polymerization step may be constant from beginning to end, or may be gradually raised.

When the 10-hour half-life temperature of the first polymerization initiator is T1 (° C) and the 10-hour half-life temperature of the second polymerization initiator is T2 (° C), the polymerization temperature t1 (° C) of the first polymerization step is The following relationship: T1 + 5 ≦ t1 ≦ T1 + 20
T2-60 ≦ t1 ≦ T2
Meet. When t1 is smaller than T1 + 5, the molecular weight of the toner binder becomes too high, and the toner fixability may deteriorate. When t1 is larger than T1 + 20, the molecular weight of the toner binder becomes too low, and the durability and storage stability of the toner may be deteriorated. Moreover, when t1 is smaller than T2-60, the temperature difference between t1 and t2 becomes excessively large, and it takes a lot of time and energy to raise the temperature, so that productivity is lowered. When t1 is larger than T2, the second polymerization initiator is largely decomposed in the first polymerization step, and the effect of reducing the unreacted polymerizable monomer remaining in the dispersion liquid in the second polymerization step is reduced. Not enough.

(Second polymerization step)
The unreacted polymerizable monomer in the dispersion obtained through the first polymerization step is polymerized in the second polymerization step. The polymerization temperature t2 (° C.) in the second polymerization step has the following relationship: T2-30 ≦ t2 ≦ T2 + 80
Meet. When t2 is smaller than T2-30, the second polymerization initiator hardly decomposes in the second polymerization step, and the effect of reducing the unreacted polymerizable monomer remaining in the dispersion liquid in the second polymerization step Cannot be obtained. When t2 is larger than T2 + 80, the polymerization temperature in the second polymerization step becomes too high, so that a part of the dispersion is vaporized, and the pressure fluctuation increases in the ejector or in the external circulation path, and the dispersion circulation becomes unstable. . In some cases, circulation may not be possible. If the polymerization temperature in the second polymerization step is too high in a state where the circulation is not stable, heat is locally applied to cause the particles in the dispersion to coalesce or in the dispersion in part of the external circulation path. Particle adhesion will occur. When the coalesced particles and deposits are mixed in the toner, the electrophotographic characteristics are deteriorated.

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

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

  The dispersion and gas mixed in this way are discharged from the discharge nozzle 7 to the external circulation path in a mixed state, and polymerization by the second polymerization initiator proceeds inside the external circulation path. The shape of the discharge nozzle 7 is not particularly limited, but the cross-sectional area of the discharge nozzle is preferably increased toward the outside of the casing. By increasing the discharge nozzle from the small cross-sectional area toward the outside of the casing, it is possible to efficiently generate the effect of circulating the mixture of the dispersion liquid and the gas by the blown gas to the external circulation path. The blowing nozzle 6 and the discharge nozzle 7 are not particularly limited, but are preferably installed at opposing positions.

  In the ejector 4 having the above-described preferred form, the dispersion is sucked into the ejector and discharged from the discharge nozzle by the venturi effect generated by blowing the gas from the blow 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 are efficiently transferred to the gas side and the organic volatile substances are efficiently removed. Furthermore, a larger amount of gas is blown than in the conventional method in which the dispersion liquid is sent to the external circulation path by a pump as shown in FIG. 4 and the gas is blown from the gas blowing port 13 provided in the external circulation path. It is preferable because organic volatile substances can be efficiently removed.

  As in the organic volatile substance removing apparatus in FIG. 1, the dispersion liquid preferably returns to the polymerization vessel through the external circulation path 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 circulation device such as a pump, thereby reducing the circulation function.

  Various gases such as helium, neon, argon, krypton, radon, nitrogen, carbon dioxide, water vapor, air, and ozone can be selected as the gas blown into the blowing nozzle 6. The gas can be used alone or in combination of two or more in any ratio. Among gases, it is more preferable to use water vapor. Since water vapor has a large low-pressure molar heat capacity among many gases, it is more preferable because it can efficiently remove organic volatile substances. In addition, it is preferable to recover the gas immediately after the mixture of the dispersion and the gas returns from the external circulation path to the polymerization vessel. When the amount of recovered gas is less than the amount of gas blown, the pressure in the polymerization vessel increases, and the circulation of the dispersion may be delayed. When the gas is water vapor, it is preferable because water vapor can be recovered by various condensers. In addition, when the dispersion medium of the dispersion liquid is an aqueous dispersion medium, the use of water vapor hardly affects the change in pH due to the gas being dissolved in the dispersion medium, and has little influence on the particles in the dispersion liquid. It can be used suitably.

  The polymerization temperature in the second polymerization step is preferably 100 ° C. or higher and 160 ° C. or lower, and more preferably 100 ° C. or higher and 150 ° C. or lower. A polymerization temperature in the second polymerization step of 100 ° C. or higher and 160 ° C. or lower is preferable because organic volatile substances can be efficiently reduced. Moreover, it is preferable if the polymerization temperature in the second polymerization step is 150 ° C. or lower because pressure fluctuations in the ejector and in the external circulation path can be suppressed, and the circulation of the dispersion liquid becomes stable. When the circulation becomes unstable, heat is locally applied, and particles in the dispersion liquid adhere to a part of the external circulation path and cannot be circulated. When the polymerization temperature in the second polymerization step exceeds 100 ° C., the temperature exceeding 100 ° C. can be achieved by reducing the back pressure valve 14 to bring the inside of the external circulation path 3 into a pressurized state.

  As a conventional method for removing organic volatile substances at a temperature exceeding 100 ° C., there is a method using the apparatus shown in FIG. In this method, the entire polymerization vessel can be pressurized by blowing air, nitrogen, or other gas into the polymerization vessel 2 from the gas blowing line 16 for pressurization. However, in the method of pressurizing the entire polymerization container, the polymerization container must be sealed, and the volatile organic volatile substances cannot be removed outside the polymerization container, so the reduction effect of organic volatile substances may be insufficient. .

(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 particles obtained through the polymerization step. Thereafter, the particles are separated from the liquid phase by a general solid-liquid separation method. In order to completely remove the acid or alkali and the dispersion stabilizer component dissolved therein, the particles are washed again with water. This washing process is repeated several times, and after sufficient washing is performed, solid-liquid separation is performed again. Thereafter, it is dried by a known drying means.

(Classification process)
The particles obtained in this way have a sufficiently sharp particle size compared to conventional pulverized toner, but when a sharper particle size is required, the desired particle size can be obtained by classifying with an air classifier or the like. Particles deviating from the particle size distribution can 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 used in the present invention)
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 used in the present invention)
The toner obtained by the production method of the present invention contains a pigment as a colorant. As a pigment used for a cyan colorant, a copper phthalocyanine compound and a derivative thereof, an anthraquinone compound, and a basic dye lake compound can be used. Specific examples include the following. C. I. Pigment Blue 15, 15: 1, 15: 2, 15: 3 and 15: 4.

  As the pigment used for the magenta colorant, condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinones, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds and perylene compounds can be used. Specific examples include the following. C. I. Pigment violet 19, C.I. I. Pigment Red 31, 57, 122, 150 and 269.

  As the pigment used for the yellow colorant, condensed azo compounds, isoindolinone compounds, anthraquinone compounds, azo metal complexes, methine compounds, and allylamide compounds can be used. Specific examples include the following. C. I. Pigment Yellow 74, 93, 120, 151, 155, 180 and 185.

  As the black colorant, carbon black, a magnetic material, and a color tone adjusted to black using the yellow, magenta, and cyan colorants can be used.

  The addition amount of these pigments 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 used in the present invention)
The toner obtained by the production method of the present invention may contain a wax. In that case, at least one of the waxes preferably has a melting point (a 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 more and 120 ° C. or less, and 50 ° C. or more and 100 ° C. The following is more preferable. Further, it is preferably a wax that is solid at room temperature, and in particular, a solid wax having a melting point of 50 ° C. or higher and 100 ° C. or lower is preferable from the viewpoint of toner blocking resistance, durability of a large number of sheets, low-temperature fixability, and offset resistance.

  Examples of the wax include paraffin wax, polyolefin wax, polymethylene wax such as microcrystalline wax and Fischer-Tropsch wax, petroleum wax such as amide wax and petrolatum and derivatives thereof, montan wax and derivatives thereof, carnauba wax and candelilla wax. Use of known waxes such as natural waxes and derivatives thereof, hydrogenated castor oil and derivatives thereof, vegetable waxes, animal waxes, higher fatty acids, long chain alcohols, ester waxes, ketone waxes and derivatives thereof such as graft compounds and block compounds Is possible. These can be used alone or in combination.

(Polymerizable monomer)
Specific examples of the polymerizable monomer that can be used are as follows. Styrene; α-methylstyrene, β-methylstyrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, 2,4-dimethylstyrene, pn-butylstyrene, p-tert-butylstyrene, p- styrene derivatives such as n-hexyl styrene, pn-octyl styrene, pn-nonyl styrene, pn-decyl styrene, pn-dodecyl styrene, p-methoxy styrene, p-phenyl styrene; methyl acrylate, 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 phosphate ethyl methacrylate, dibutyl phosphate Such methacrylic polymerizable monomers of methacrylate.

(First polymerization initiator and second polymerization initiator)
Examples of the first polymerization initiator and the second polymerization initiator used in the present invention include organic peroxide initiators.

  The following are mentioned as an organic peroxide type | system | group initiator. Benzoyl peroxide, methyl ethyl ketone peroxide, diisopropyl peroxide, cumene hydroperoxide, 2,4-dichlorobenzoyl peroxide, lauroyl peroxide, tert-butyl-peroxypivalate, di-tert-butyl-peroxide, 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 (ter -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-butylperoxy) -butane, n-butyl-4,4-di (tert-butylperoxy) -valerate, ethyl- , 3-Di (tert-butylperoxy) -butyrate, 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-butylperoxide) Oxy) -hexyne-3.

  The first polymerization initiator and the second polymerization initiator used in the present invention are selected by comprehensively considering the 10-hour half-life temperature, the properties of decomposition byproducts, and the like. The addition amount of the polymerization initiator is generally 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.

(External additive)
External additives can be added to the toner particles obtained by the production method of the present invention for the purpose of improving various powder characteristics. Examples of the external additive include the following. Metal oxides such as aluminum oxide, titanium oxide, strontium titanate, cerium oxide, magnesium oxide, tin oxide and 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 and silica.

  These external additives are used in an amount of 0.01 to 10 parts by weight, preferably 0.05 to 5 parts by weight, based on 100 parts by weight of toner particles. These external additives may be used alone or in combination.

  These external additives are more preferably hydrophobized.

  Hereinafter, various methods for measuring toner particles obtained by the suspension polymerization method will be described.

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

  A specific measurement method is as follows. First, about 20 ml of ion-exchanged water from which impure solids are removed in advance is put in a glass container. In this, "Contaminone N" (nonionic surfactant, anionic surfactant, 10% by weight aqueous solution of neutral detergent for pH7 precision measuring instrument cleaning, made by organic builder, manufactured by Wako Pure Chemical Industries, Ltd. About 0.2 ml of a diluted solution obtained by diluting the solution with ion exchange water about 3 times by mass. Further, about 0.02 g of a measurement sample is added, and dispersion treatment is performed for 2 minutes using an ultrasonic disperser to obtain a dispersion for measurement. In that case, it cools suitably so that the temperature of a dispersion liquid may become 10 to 40 degreeC. As the ultrasonic disperser, a desktop type ultrasonic cleaner disperser (for example, “VS-150” (manufactured by VervoCrea)) having an oscillation frequency of 50 kHz and an electric output of 150 W is used. Ion exchange water is added, and about 2 ml of the above-mentioned Contaminone N is added to this water tank.

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

  In the measurement, automatic focus adjustment is performed using standard latex particles (eg, “RESEARCH AND TEST PARTICLES Latex Microsphere Suspensions 5100A” manufactured by Duke Scientific) diluted with ion-exchanged water before starting the measurement. Thereafter, it is preferable to perform focus adjustment every two hours from the start of measurement.

  In the examples of the present application, a flow-type particle image analyzer that has been issued a calibration certificate issued by Sysmex Corporation, which has been calibrated by Sysmex Corporation, was used. The measurement was performed under the measurement and analysis conditions when the calibration certificate was received, except that the analysis particle diameter was limited to the equivalent circle diameter (number) of 4.044 μm or more and less than 100.0 μm.

<Measurement method of volume-based median diameter (Dv50), 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 a measuring device, a precise particle size distribution measuring device “Coulter Counter Multisizer 3” (registered trademark, manufactured by Beckman Coulter, Inc.) using a pore electrical resistance method equipped with a 100 μm aperture tube is used. For setting the measurement conditions and analyzing the measurement data, the attached dedicated software “Beckman Coulter Multisizer 3 Version 3.51” (manufactured by Beckman Coulter, Inc.) is used. Note that the measurement is performed with 25,000 effective measurement channels.

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

  Prior to 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 in the control mode to 50,000 particles, set the number of measurements once, and set the Kd value to “standard particles 10.0 μm” (Beckman Coulter) Set the value obtained using By pressing the “Threshold / Noise Level Measurement Button”, the threshold and noise level are automatically set. In addition, the current is set to 1600 μA, the gain is set to 2, the electrolyte is set to ISOTON II, and the “aperture tube flush after measurement” is checked.

  In the “Pulse to particle size conversion setting” screen of the dedicated software, the bin interval is set to logarithmic particle size, the particle size bin is set to 256 particle size bin, and the particle size range is set to 2 μm to 60 μm.

The specific measurement method is as follows.
(1) About 200 ml of the electrolytic aqueous solution is put in a glass 250 ml round bottom beaker exclusively for Multisizer 3, set on a sample stand, and the stirrer rod is stirred counterclockwise at 24 rotations / second. Then, the dirt and bubbles in the aperture tube are removed by the “aperture flush” function of the dedicated software.
(2) About 30 ml of the electrolytic aqueous solution is put into a glass 100 ml flat bottom beaker. In this, "Contaminone N" (nonionic surfactant, anionic surfactant, 10% by weight aqueous solution of neutral detergent for pH7 precision measuring instrument cleaning, made by organic builder, manufactured by Wako Pure Chemical Industries, Ltd. About 0.3 ml of a diluted solution obtained by diluting 3) with ion-exchanged water is added.
(3) Two oscillators with an oscillation frequency of 50 kHz are incorporated with the phase shifted by 180 degrees, and an ultrasonic disperser “Ultrasonic Dissipation System Tetra 150” (manufactured by Nikkaki Bios Co., Ltd.) having an electrical output of 120 W is prepared. About 3.3 l of ion-exchanged water is placed in the water tank of the ultrasonic disperser, and about 2 ml of Contaminone N is added to 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. And the height position of a beaker is adjusted so that the resonance state of the liquid level of the electrolyte solution in a beaker may become the maximum.
(5) In a state where the electrolytic aqueous solution in the beaker of (4) is irradiated with ultrasonic waves, about 10 mg of toner is added to the electrolytic aqueous solution little by little and dispersed. Then, the ultrasonic dispersion process is continued for another 60 seconds. In the ultrasonic dispersion, the temperature of the water tank is appropriately adjusted so as to be 10 ° C. or higher and 40 ° C. or lower.
(6) To the round bottom beaker of (1) installed in the sample stand, the electrolyte solution of (5) in which the toner is dispersed is dropped using a pipette, and the measurement concentration is adjusted to about 5%. . The measurement is performed until the number of measured particles reaches 50,000.
(7) The measurement data is analyzed with the dedicated software attached to the apparatus, 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 to 1, the sharper the particle size distribution.

<Measurement method of organic volatile substances>
(1) The sample used for measurement was prepared by the following procedure.

  About 100 ml of the toner particle dispersion is added with a treatment solution having a pH of 1.4 or less by adding hydrochloric acid to a pressure filter to perform filtration. After filtration, 200 ml of water was added to the pressure filter and filtered again for washing. After performing the washing operation twice, the pressure inside the pressure filter is set to 0.2 MPa, and the pressure is applied for 10 minutes to obtain a cake of toner particles. The filtered toner particle cake is crushed and dried at room temperature for 18 hours to obtain toner particles.

  The amount of the organic volatile substance in terms of toluene of the toner by the headspace method can be measured as follows.

  In a headspace vial (volume: 22 ml), 300 mg of toner particles are precisely weighed and sealed with a crimper 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. And the total area value of the peak of the obtained GC chart is calculated by data processing. At this time, an empty vial not containing toner particles is also measured as a blank at the same time, and a measurement value in the blank measurement is subtracted from the toner measurement data.

  On the other hand, several vials (for example, 0.1 μl, 0.5 μl, 1.0 μl) prepared by precisely weighing toluene are prepared in the vial, and each measurement is performed under the following analysis conditions before measuring the toner particle sample. After this, a calibration curve is created 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 an amount based on the toner mass.

(2) Measuring apparatus and measuring conditions Headspace sampler: HEWLETT PACKARD 7694
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 × 30 m)
Oven: (1) 35 ° C .: Hold for 20 minutes, (2) Hold 20 minutes at 20 ° C./minute, hold for 20 minutes INJ: 300 ° C., splitless, constant pressure (20 psi) mode DET: 320 ° C.

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

The manufacturer, trade name, and 10 hour half-life temperature of each polymerization initiator used in the following Examples and Comparative Examples are as shown below.
Tert-Butyl-peroxypivalate (manufactured by NOF Corporation, trade name “Perbutyl PV”, 10 hour half-life temperature: 55 ° C.)
・ Di-tert-butyl-peroxide (manufactured by NOF Corporation, trade name “Perbutyl D”, 10 hour half-life temperature: 124 ° C.)
Tert-butyl-peroxy-2-ethylhexanoate (manufactured by NOF Corporation, trade name “Perbutyl O”, 10 hour half-life temperature: 72 ° C.)
Tert-butyl-peroxy-isopropyl-monocarbonate (manufactured by NOF Corporation, trade name “Perbutyl I”, 10 hour half-life temperature: 99 ° C.)
Tert-butyl-hydroperoxide (manufactured by NOF Corporation, trade name “Perbutyl H”, 10 hour half-life temperature: 133 ° C.)
Tert-butyl-peroxy-2-ethylhexyl-monocarbonate (manufactured by NOF Corporation, trade name “Perbutyl E”, 10 hour half-life temperature: 99 ° C.)
1,1,3,3-tetramethylbutyl-peroxy-2-ethylhexanoate (manufactured by NOF Corporation, trade name “Perocta O”, 10 hour half-life temperature: 65 ° C.)

[Example 1]
A toner was manufactured according to the following procedure.

To 1000 parts by mass of ion-exchanged water in the reaction vessel, 15.3 parts by mass of sodium phosphate and 4.9 parts by mass of 10% hydrochloric acid were added, and kept at 60 ° C. for 60 minutes while purging with N ₂ . T.A. K. Using a homomixer (manufactured by Koki Kogyo Kogyo Co., Ltd.), while stirring at 12,000 rpm, an aqueous solution of calcium chloride in which 8.5 parts by mass of calcium chloride is dissolved is added to 10 parts by mass of ion-exchanged water, and a dispersion stabilizer is included. An aqueous medium was prepared.

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 The above materials were put into an attritor (Mitsui Miike Chemical Co., Ltd.) and further dispersed at 220 rpm for 5 hours using zirconia particles having a diameter of 1.7 mm.

In this dispersion,
Styrene 16 parts by mass n-butyl acrylate 20 parts by mass Amorphous polyester resin (Mw = 10000, acid value = 10.0 mgKOH / g)
2.5 parts by mass of wax (Nippon Seiki Co., Ltd., trade name = “paraffin wax 135”, melting point = 58 ° C.)
12 parts by weight were added.

  In a separate container, keep the material at 63 ° C. K. Using a homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.), the solution was uniformly dissolved and dispersed at 500 rpm. In this, 2.0 parts by mass of perbutyl PV as a first polymerization initiator and 0.5 parts by mass of perbutyl D as a second polymerization initiator were dissolved to prepare a polymerizable monomer composition.

The polymerizable monomer composition was charged into the aqueous medium, 60 ° C., the N ₂ purge under, T. K. The mixture was stirred with a homomixer at 10,000 rpm for 5 minutes, and granulated at pH 5.5. Then, it superposed | polymerized over 5 hours at 67 degreeC, stirring with a paddle stirring blade (1st polymerization process).

  Thereafter, this dispersion was polymerized using the organic volatile substance removing apparatus shown in FIG. 1 (second polymerization step). The specific procedure is as follows.

  The dispersion was transferred to the polymerization vessel 2 and heated to 95 ° C. while stirring with the stirring blade 10. Then, the polymerization container bottom valve 11 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 is water vapor, and the second polymerization step is performed for 5 hours by using a water vapor pressure of 0.42 MPa and a temperature of 100 ° C. so that the liquid temperature of the dispersion becomes 100 ° C. It was. The blowing flow rate was 80 kg / hr. At this time, the circulation flow rate of the dispersion was 7 l / min.

  After cooling the dispersion after the second polymerization step, hydrochloric acid was added to adjust the pH to 1.4, and the mixture was stirred for 2 hours. Then, after filtration and washing with water, the toner 1 was obtained by drying at a temperature of 40 ° C. for 48 hours.

  For the toner 1 thus obtained, the organic volatile substance concentration was measured. Further, in order to evaluate the degree of adhering contamination, the volume-based median diameter (Dv50), Dv50 / Dn50, and aspect ratio of toner 1 were measured.

[Example 2]
Toner 2 was obtained by the same conditions and method as in Example 1 except that the second polymerization initiator was replaced with perbutyl O.

Example 3
Toner 3 was obtained by the same conditions and method as in Example 1 except that the polymerization temperature in the second polymerization step was 150 ° C.

Example 4
Toner 4 was obtained by the same conditions and method as in Example 2 except that the polymerization temperature in the second polymerization step was 150 ° C.

Example 5
Toner 5 was obtained by the same conditions and method as in Example 1 except that the second polymerization initiator was replaced with perbutyl I and the polymerization temperature in the second polymerization step was 125 ° C.

Example 6
Toner 6 was obtained by the same conditions and method as in Example 5 except that the polymerization temperature in the first polymerization step was 62 ° C.

Example 7
Toner 7 was obtained by the same conditions and method as in Example 5 except that the polymerization temperature in the first polymerization step was 72 ° C.

Example 8
The toner 8 was replaced under the same conditions and method as in Example 1 except that the second polymerization initiator was replaced with perbutyl H, the polymerization temperature in the first polymerization step was 74 ° C., and the polymerization temperature in the second polymerization step was 105 ° C. Obtained.

Example 9
Toner 9 was obtained by the same conditions and method as in Example 1 except that the second polymerization initiator was replaced with perbutyl E, the polymerization temperature in the first polymerization step was 70 ° C., and the polymerization temperature in the second polymerization step was 115 ° C. It was.

Example 10
Example 1 except that the first polymerization initiator is replaced with perocta O, the second polymerization initiator is replaced with perbutyl E, the polymerization temperature in the first polymerization step is 72 ° C., and the polymerization temperature in the second polymerization step is 115 ° C. A toner 10 was obtained according to the above conditions and method.

Example 11
Toner 11 was obtained by the same conditions and method as in Example 1 except that the second polymerization initiator was replaced with perbutyl O and the polymerization temperature in the second polymerization step was 95 ° C.

Example 12
Toner 12 was obtained by the same conditions and method as in Example 1 except that the second polymerization initiator was replaced with perbutyl I and the polymerization temperature in the second polymerization step was 155 ° C.

[Comparative Example 1]
In place of the organic volatile substance removing apparatus shown in FIG. 1, the same conditions as in Example 5 except that the entire polymerization vessel was pressurized using the organic volatile substance removing apparatus shown in FIG. The toner 13 was obtained by the method.

[Comparative Example 2]
In place of the organic volatile substance removing apparatus shown in FIG. 1, the toner 14 was prepared under the same conditions and method as in Example 5 except that the second polymerization step was carried out at 100 ° C. using the organic volatile substance removing apparatus shown in FIG. Got.

[Comparative Example 3]
Experiments were performed under the same conditions and method as in Example 5 except that the second polymerization step was performed using the organic volatile substance removing apparatus shown in FIG. 4 instead of the organic volatile substance removing apparatus shown in FIG. However, the experiment was stopped because no circulation was performed in the second polymerization step. When the external circulation path was checked, deposits were found near the pump.

  Table 1 shows the 10-hour half-life temperature of the polymerization initiator added in the above Examples and Comparative Examples, the polymerization temperature in the first polymerization step, the polymerization temperature in the second polymerization step, and the apparatus configuration used.

  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 ppm B: 8 ppm or more and less than 16 ppm C: 16 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: 0.96 or more B: 0.90 or more and less than 0.96 C: Less than 0.90

  1: organic volatile substance removal device, 2: polymerization vessel, 3: external circulation path, 4: ejector, 5: casing, 6: blowing nozzle, 7: discharge nozzle, 8: pump, 9: suction port, 10: stirring blade 11: polymerization vessel bottom valve, 12: gas blowing line, 13: gas blowing port, 14: back pressure valve, 15: return port, 16: gas blowing line for pressurization

Claims (3)

A granulating step of forming particles of a polymerizable monomer composition containing a polymerizable monomer in an aqueous medium, and the polymerizable monomer contained in the particles of the polymerizable monomer composition. A method for producing resin particles having a polymerization step for polymerization,
The polymerization step includes a first polymerization step in which polymerization is performed using a first polymerization initiator and a second polymerization step that is performed after the first polymerization step and performs polymerization using a second polymerization initiator. And
The first polymerization step satisfies the following relationship when the 10-hour half-life temperature of the first polymerization initiator is T1 (° C) and the 10-hour half-life temperature of the second polymerization initiator is T2 (° C). A step in which polymerization is carried out at a temperature t1 (° C.),
T1 + 5 ≦ t1 ≦ T1 + 20
T2-60 ≦ t1 ≦ T2
The second polymerization step is a step in which polymerization is performed at a temperature t2 (° C.) that satisfies the following relationship:
T2-30 ≦ t2 ≦ T2 + 80
T1, T2, t1 and t2 satisfy the following relationship:
T1 <T2
t1 <t2
The second polymerization step is a step of polymerizing inside the external circulation path connected to the polymerization vessel,
The external circulation path is provided with an ejector, and the ejector is
(I) a casing;
(Ii) a blowing nozzle for blowing gas into the casing;
(Iii) a suction port for sucking the liquid discharged from the polymerization 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;
The manufacturing method of the resin particle characterized by having.   The method for producing resin particles according to claim 1, wherein a polymerization temperature t2 in the second polymerization step is 100 ° C or higher and 150 ° C or lower.   The method for producing resin particles according to claim 1, wherein the resin particles are toner particles.

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