JP4629569B2 - Method for producing yellow toner - Google Patents

Description

  The present invention relates to a method for producing toner used in electrophotography, electrostatic recording, electrostatic printing, and the like.

As a method for producing a chemical toner, a polymerization method and an emulsion dispersion method are known. Among these methods, a method for producing a toner by an emulsification dispersion method is a method in which, for example, a mixture of a binder resin and a colorant is mixed with an aqueous medium and emulsified to obtain toner particles. In this method, for example, when polyester is used as the binder resin, there are problems that the operation is complicated, the production time is long, and the shape cannot be controlled. In such a case, there is also a problem that the yellow pigment turns red upon alkali addition.
In addition, as a technique for obtaining a toner from a binder resin containing polyester and a colorant in an aqueous medium, for example, a toner produced from the binder resin and a coloring component in an aqueous medium, There is a technology for improving dispersibility and the like by an image forming toner (see Patent Document 1) in which 100% by weight is a polyester resin and the coloring component contains a colorant, a basic polymer copolymer dispersant, and a pigment derivative. Although disclosed, in such a technique, since an organic solvent is used for dispersing the binder resin, the types of resins that can be used are limited, and the process load such as solvent recovery is increased. There was a problem.

JP 2005-181835 A

  An object of the present invention is to provide a method capable of easily producing a toner having a narrow particle size distribution in a short production time while controlling the toner particle size even when a binder resin containing polyester is used. Another object of the present invention is to provide a method for producing a yellow toner capable of suppressing redness of a pigment and greatly reducing the process load.

The present invention
(I) (1) A step of dispersing Color Index Pigment Yellow 74 (Pigment Yellow 74) in a molten binder resin containing polyester, and (2) containing Pigment Yellow 74 in an aqueous medium in the presence of alkali. And (b) further comprising (3) agglomerating the binder resin emulsified particles containing pigment yellow 74 in an aqueous medium. The method for producing a yellow toner as described in (a) above.

  According to the method for producing a yellow toner of the present invention, even when a binder resin containing polyester is used, a toner having a narrow particle size distribution can be easily produced in a short production time while controlling the toner particle size. Moreover, redness of the pigment can be suppressed and the process load can be greatly reduced.

  The present invention includes (1) a step of dispersing Color Index Pigment Yellow 74 (hereinafter referred to as PY74) in a molten binder resin containing polyester, and (2) in an aqueous medium in the presence of an alkali. A process for producing emulsified particles of the binder resin containing PY74. Below, the said process (1) and (2) is demonstrated.

Process (1)
Step (1) is a step of dispersing PY74 in a molten binder resin containing polyester.
The binder resin used in the method for producing a yellow toner of the present invention contains polyester from the viewpoints of colorant dispersibility, fixability and durability. The content of the polyester is preferably 60% by weight or more, more preferably 70% by weight or more, and still more preferably 80% by weight or more from the viewpoint of fixing property and durability in the binder resin. Examples of binder resins other than polyester include known resins used in toners, such as styrene-acrylic resins, epoxy resins, polycarbonates, and polyurethanes.

Although the raw material monomer of polyester is not particularly limited, a known alcohol component and a known carboxylic acid component such as carboxylic acid, carboxylic acid anhydride, or carboxylic acid ester are used.
Examples of the alcohol component include polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane and polyoxyethylene (2.2) -2,2-bis (4-hydroxyphenyl) propane. Bisphenol A alkylene (2 to 3 carbon atoms) oxide (average number of added moles 1 to 16) adduct, ethylene glycol, propylene glycol, glycerin, pentaerythritol, trimethylolpropane, hydrogenated bisphenol A, sorbitol, or alkylene thereof (C2-C4) oxide (average addition mole number 1-16) adduct etc. are mentioned.

The carboxylic acid component includes dicarboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid, fumaric acid, maleic acid, adipic acid and succinic acid, alkyl groups having 1 to 20 carbon atoms such as dodecenyl succinic acid and octenyl succinic acid, or carbon. Trivalent or higher polyvalent carboxylic acids such as succinic acid, trimellitic acid and pyromellitic acid substituted with alkenyl groups of 2 to 20, anhydrides of these acids and alkyls of these acids (1 to 3 carbon atoms) ) Esters and the like.
The polyester can be produced, for example, by subjecting an alcohol component and a carboxylic acid component to condensation polymerization at a temperature of 180 to 250 ° C. in an inert gas atmosphere, if necessary, using an esterification catalyst.

From the viewpoint of storage stability of the toner, the softening point of the polyester is preferably 80 to 165 ° C, and the glass transition temperature is preferably 50 to 85 ° C. The acid value is preferably 6 to 35 mgKOH / g, more preferably 10 to 35 mgKOH / g, and still more preferably 15 to 35 mgKOH / g, from the viewpoint of manufacturability during emulsification. The desired softening point and acid value can be obtained by adjusting the condensation polymerization temperature and reaction time.
In addition, from the viewpoint of chargeability, as an acid component, aromatic carboxylic acids such as terephthalic acid, trimellitic acid, isophthalic acid, and anhydrides thereof, fumaric acid, adipic acid, succinic acid, and derivatives and anhydrides thereof It is preferable to use a polyester obtained by using an aliphatic carboxylic acid together.

  PY74 used as a colorant is represented by the following structural formula.

Conventionally, as a yellow pigment of toner, C.I. I. Although PY17 was often used, the use of a dichlorobenzidine-free yellow pigment is desired because of safety issues. As dichlorobenzidine-free yellow pigments, PY180, 185, 151, 154, 155, 167, 139, 74 and the like are known, and among them, coloring power, From the viewpoint of pigment dispersibility, PY180, 185, and 74 were widely used.
However, in the method for producing a polyester toner including a reaction in which an alkali is added to the emulsification step to make the polyester terminal a salt, when a yellow pigment is used, there is a problem that the yellow pigment turns red upon alkali addition. It was also necessary to consider the choice of pigment.
From the above points, the present invention has found that PY74 is particularly effective among the above yellow pigments from the viewpoints of alkali resistance, dispersibility of the pigment in the polyester, and the like.

In the step (1), the use ratio of the binder resin and PY74 is preferably 60:40 to 97: 3 by weight from the viewpoint of pigment dispersibility and toner productivity, and 70:30 to 97: 3 is more preferable.
In the step (1), PY74 is dispersed in the molten binder resin. From the viewpoint of uniformly dispersing the resin particles and PY74, the temperature is 85 ° C to 100 ° C, and further 85 ° C to 98 ° C. It is preferable to perform dispersion at the following temperature.

  As a specific method of the step (1), for example, (1) a dry powdery PY74, a binder resin, and, if necessary, a dispersion aid such as water are charged into a mixer or a kneader and mixed. And (2) a method in which the binder resin is moistened and heated at the above temperature under pressure or normal pressure to melt and knead the PY74 and the binder resin, and then the moisture is evaporated and dried under normal pressure or reduced pressure. After the dried PY74 and the binder resin are heated at the above temperature to melt the resin, water is added and the PY74 and the binder resin are melt-kneaded under pressure or normal pressure, and the moisture is reduced to normal pressure or reduced pressure. (3) A method in which PY74 press cake (including an aqueous paste) and a resin are melt-kneaded at the above temperature to transfer the aqueous phase PY74 to the resin phase to remove moisture. Etc.

Process (2)
Step (2) is a step of producing emulsified particles of the binder resin containing the PY74 in an aqueous medium in the presence of an alkali.
The aqueous medium used in the step (2) may contain a solvent such as an organic solvent, an inorganic salt such as an alkali metal salt, etc., but preferably contains 95% by weight or more, more preferably 99% by weight or more. In particular, in the present invention, the binder resin containing PY74 can be atomized by using only water without substantially using an organic solvent.
In the step (2), from the viewpoint of improving the emulsification stability of the binder resin containing PY74, it is preferably 5 parts by weight or less, more preferably 0.1-3. 5 parts by weight, more preferably 0.1 to 3 parts by weight of a surfactant is present.

  Examples of the surfactant include anionic surfactants such as sulfate ester type, sulfonate type, phosphate ester type, and soap type; cationic surfactants such as amine salt type and quaternary ammonium salt type; polyethylene Nonionic surfactants such as glycol-based, alkylphenol ethylene oxide adduct-based, polyhydric alcohol-based and the like can be mentioned. Among these, ionic surfactants such as anionic surfactants and cationic surfactants are preferably used. The nonionic surfactant is preferably used in combination with an anionic surfactant or a cationic surfactant.

  Specific examples of the anionic surfactant include sodium dodecyl benzene sulfonate, sodium dodecyl sulfate, sodium alkyl ether sulfate, sodium alkyl naphthalene sulfonate, sodium dialkyl sulfosuccinate and the like. Specific examples of the cationic surfactant include alkylbenzene dimethyl ammonium chloride, alkyl trimethyl ammonium chloride, distearyl ammonium chloride and the like. Specific examples of the nonionic surfactant include polyoxyethylene alkyl ether, polyoxyethylene alkylphenyl ether, sorbitan monostearate, polyoxyethylene alkylamine and the like. Each of the surfactants may be used alone or in combination of two or more.

In the step (2), it is preferable to add an alkaline aqueous solution equivalent to the acid group of the polyester in the binder resin to disperse the binder resin.
At this time, a charge adjusting agent, a release agent such as wax, and the like can also be used. In addition, it is not limited to the form of the binder resin, and the toner raw material such as a colorant previously melted and kneaded in the binder resin may be dispersed in the form of granules.

In the dispersion of the binder resin containing PY74, the concentration of the aqueous alkali solution added is preferably 1 to 20% by weight, more preferably 1 to 10% by weight, and still more preferably 1.5 to 7.5% by weight. As for the alkali to be used, it is preferable to use an alkali that enhances the surface activity when the polyester becomes a salt. Examples thereof include monovalent alkali metal hydroxides such as potassium hydroxide and sodium hydroxide.
From the viewpoint of emulsion stability, the alkali is preferably present so that the pH value of the emulsion is 5.6 to 8.0, more preferably 5.8 to 7.0.

In the production method of the present invention, PY74 is dispersed in the binder resin in the step (1), neutralized at a temperature higher than the glass transition point of the binder resin, and then at a temperature higher than the glass transition point. Binder resin emulsified particles can be produced by phase inversion emulsification by adding water.
The water addition rate is preferably 0.5 to 50 g / min, more preferably 0.5 to 40 g / min, and even more preferably 0.5 to 30 g per 100 g of resin from the viewpoint of effectively emulsifying. / Min. This addition rate is generally maintained until an O / W type emulsion is substantially formed, and there is no particular limitation on the addition rate of water after the formation of the O / W type emulsion.

  Further, the temperature at this time is preferably in the range from the glass transition point of the binder resin to the softening point from the viewpoint of preparing a fine PY74-containing resin emulsion. By carrying out the emulsification at a temperature within the above range, the emulsification is carried out smoothly and no special apparatus is required for heating. From this point, the above temperature is preferably not less than the glass transition point of the binder resin + 10 ° C. (meaning a temperature 10 ° C. higher than the glass transition point, hereinafter the same), and is not more than −5 ° C. softening point. Is preferred. When a mixed resin is used as the binder resin, the softening point of the mixed resin mixed and melted at the mixing ratio is defined as the softening point of the binder resin. Moreover, when using a masterbatch, it is set as the softening point of mixed resin including the resin used for it.

The volume median particle size (D ₅₀ ) of the resin emulsified particles containing PY74 is preferably 0.05 to 3 μm, more preferably 0.05 to 1 μm, from the viewpoint of performing uniform aggregation in the subsequent aggregation process. 0.05 to 0.8 μm is more preferable.
The binder resin emulsion containing PY74 thus obtained is subjected to aggregation and coalescence by subjecting the emulsified particles therein (hereinafter sometimes referred to as primary particles) to the following step (3). It is preferable to use one.

Process (3)
Step (3) is a step of aggregating the emulsified particles of the binder resin containing PY74 in an aqueous medium.
In the present invention, the emulsified particles in the resin emulsion containing PY74 obtained in the above step (2) are aggregated (hereinafter referred to as the aggregation step) and further united (hereinafter referred to as the coalescence step). A yellow toner can be obtained.
In the aggregation step, the pH value in the system is preferably 2 to 10, more preferably 2 to 9, from the viewpoint of achieving both the dispersion stability of the mixed solution and the aggregation property of the fine particles of the binder resin containing PY74. 3 to 8 are more preferable.
From the same viewpoint, the temperature in the system in the aggregation process is preferably a softening point of the binder resin of −50 ° C. or higher and a softening point of −10 ° C. or lower, more preferably a softening point of −30 ° C. or higher and a softening point of −10 ° C. or lower. .
As the aqueous medium used in the aggregation step, the same media as those mentioned in the above step (2) can be used.

  In the aggregation step, it is preferable to add an aggregating agent in order to effectively perform aggregation. As the flocculant, an inorganic metal salt, a divalent or higher valent metal complex, an ammonium salt, and the like are used in addition to the surfactant. Examples of the inorganic metal salt include metal salts such as sodium sulfate, calcium chloride, calcium nitrate, barium chloride, magnesium chloride, zinc chloride, aluminum chloride, and aluminum sulfate, and inorganic metal salts such as polyaluminum chloride and polyaluminum hydroxide. Examples of ammonium salts include quaternary ammonium salts such as tetraalkylammonium halides, ammonium halides, ammonium sulfate, ammonium acetate, ammonium benzoate, and ammonium salicylate. Among these, aluminum salts and polymers thereof, metal salts such as sodium sulfate, and ammonium salts are preferably used. In particular, an ammonium salt is preferable from the viewpoint of controlling the toner particle shape, and a trivalent aluminum salt and a polymer thereof are preferable because they have a high aggregation ability with a small addition amount and can be easily produced. From the viewpoint of controlling charging characteristics, a cationic surfactant of a metal complex or a quaternary salt is preferable.

The amount of the flocculant used is preferably 30 parts by weight or less, more preferably 0.01 to 20 parts by weight, and more preferably 0.1 to 100 parts by weight with respect to 100 parts by weight of the binder resin, from the viewpoint of the aggregation ability and the environmental resistance characteristics of the toner. More preferred is 10 parts by weight.
The flocculant is preferably added after being dissolved in an aqueous medium, and it is preferable to sufficiently stir at the time of adding the flocculant and after the addition. The obtained agglomerated particles are subjected to a step of coalescing the agglomerated particles (a coalescence step).
From the viewpoint of high image quality, the volume-median particle size of the aggregated particles is preferably 1 to 10 μm, more preferably 2 to 8 μm, and further preferably 3 to 7 μm.
In the step (3), the solid content concentration at the time when the volume-median particle size of the aggregated particles becomes 3 μm is 15 to 40% by weight, and more preferably 20 to 35% by weight from the viewpoint of particle size control. preferable.

In the coalescence process, the temperature in the system is preferably equal to or higher than the temperature in the system in the aggregation process, but the target toner particle size, particle size distribution, shape control, and particle fusing property In view of the above, the softening point of the binder resin is preferably −50 ° C. or higher and the softening point + 10 ° C. or lower, more preferably softening point −40 ° C. or higher and softening point + 10 ° C. or lower, softening point −30 ° C. or higher, softening point + 10 ° C. The following is more preferable. The stirring speed is preferably a speed at which the aggregated particles do not settle.
The coalescence process can be performed simultaneously with the aggregation process, for example, by continuously raising the temperature or by raising the temperature to a temperature at which aggregation and coalescence can be performed and then continuing stirring at that temperature.
From the viewpoint of high image quality, the volume-median particle size of the coalesced particles is preferably 1 to 10 μm, more preferably 2 to 8 μm, and further preferably 3 to 7 μm.

Toner mother particles can be obtained by subjecting the obtained coalesced particles to a solid-liquid separation process such as filtration, a washing process, and a drying process as necessary.
In the washing step, for the purpose of ensuring sufficient charging characteristics and reliability as a toner, it is preferable to use an acid to remove metal ions on the surface of the toner base particles, and washing is preferably performed a plurality of times.
In the drying step, any method such as a vibration type fluidized drying method, a spray drying method, a freeze drying method, a flash jet method, or the like can be employed. The water content after drying of the toner base particles is preferably adjusted to 1.5% by weight or less, more preferably 1.0% by weight or less, from the viewpoint of chargeability.

Yellow toner The yellow toner obtained by the production method of the present invention contains the coalesced particles (toner base particles) obtained as described above. The content of the coalesced particles in the toner is From the viewpoint of chargeability and fixability, it is preferably 95 to 100% by weight, and more preferably 96.5 to 99% by weight.

Further, from the viewpoints of high image quality and productivity, the volume median particle size (D ₅₀ ) of the yellow toner particles is preferably 1 to 10 μm, more preferably 2 to 8 μm, and further preferably 3 to 7 μm. From the same viewpoint, the particle size distribution is preferably 25% or less, more preferably 20% or less, and still more preferably 18% or less in terms of CV value (standard deviation of particle size distribution / volume average particle size (D ₅₀ ) × 100).
The softening point of the yellow toner is preferably 60 to 140 ° C., more preferably 60 to 130 ° C., and still more preferably 60 to 120 ° C., from the viewpoint of low-temperature fixability. Moreover, it is preferable that the maximum peak temperature of the endotherm by a differential scanning calorimeter is 60-140 degreeC from the same viewpoint, More preferably, it is 60-130 degreeC, More preferably, it is 0-120 degreeC.

In the yellow toner obtained by the production method of the present invention, an auxiliary agent such as a fluidizing agent can be added to the surface of the toner base particles as an external additive. External additives include known fine particles such as silica fine particles, titanium fine particles, alumina fine particles, cerium oxide fine particles, carbon black and other inorganic fine particles, and polymer fine particles such as polycarbonate, polymethyl methacrylate and silicone resin. Can be used.
The blending amount of the external additive is preferably 1 to 5 parts by weight, and more preferably 1.5 to 3.5 parts by weight with respect to 100 parts by weight of the toner base particles before processing with the external additive. However, when hydrophobic silica is used as an external additive, it is preferable to use 1 to 3 parts by weight of hydrophobic silica with respect to 100 parts by weight of toner base particles before treatment with the external additive.

  Examples of the transfer medium (recording material) to which the yellow toner of the present invention is applied include plain paper and OHP sheets used in electrophotographic copying machines and printers. The toner image transferred onto the surface of the transfer medium is heat-fixed by, for example, an overheating type fixing device, and a final toner image is formed. Examples of the heating type fixing device include a contact heating type fixing method using a heating roll and the like, and a non-contact heating type fixing method using oven heating, but a contact type fixing device should be used from the viewpoint of reliability, safety, and thermal efficiency. Is preferred.

Each property value was measured and evaluated by the following method.
[Acid value of resin]
Measured according to JIS K0070.
[Softening point of resin and toner, maximum endothermic peak temperature, melting point and glass transition point]
(1) Softening point Using a flow tester (Shimadzu Corporation, CFT-500D), a 1 g sample was heated at a heating rate of 6 ° C./min. Extrude from a 1 mm nozzle. Plot the flow tester's Bwanger drop amount against temperature, and let the softening point be the temperature at which half of the sample flowed out.

(2) Maximum endothermic peak temperature and melting point A sample was heated to 200 ° C. using a differential scanning calorimeter (Seiko Denshi Kogyo Co., Ltd., DSC210), and cooled to 0 ° C. at a temperature decreasing rate of 10 ° C./min. Measurement is performed at a heating rate of 10 ° C./min. Among the observed endothermic peaks, the temperature of the peak on the highest temperature side is defined as the highest endothermic peak temperature. When the maximum peak temperature is within 20 ° C. from the softening point, the peak temperature is taken as the melting point, and when it is 20 ° C. or more lower than the softening point, the peak is caused by the glass transition.

(3) Glass transition point A sample was heated to 200 ° C. using a differential scanning calorimeter (Seiko Denshi Kogyo Co., Ltd., DSC210), and the sample was cooled from that temperature to 0 ° C. at a temperature lowering rate of 10 ° C./min. Measured in ° C / min. When a peak is observed at a temperature 20 ° C. or more lower than the softening point, the peak temperature is measured. When a peak is not observed at a temperature 20 ° C. or higher lower than the softening point, a step is observed. The temperature at the intersection of the tangent line indicating the maximum slope of the curve and the extension line of the base line on the high temperature side of the step is read as the glass transition point. The glass transition point is a physical property peculiar to the amorphous part of the resin, and is generally observed in amorphous polyester, but is observed when amorphous part exists even in crystalline polyester. There is.

[Number average molecular weight of resin]
The molecular weight distribution is measured by gel permeation chromatography and the number average molecular weight is calculated by the following method.
(1) Preparation of sample solution Dissolve in tetrahydrofuran so that the concentration is 0.5 g / 100 ml. Subsequently, this solution is filtered using a fluororesin filter having a pore size of 2 μm (FP-200, manufactured by Sumitomo Electric Industries, Ltd.) to remove insoluble components to obtain a sample solution.
(2) Molecular weight measurement Tetrahydrofuran is allowed to flow as a solution at a flow rate of 1 ml per minute, and the column is stabilized in a constant temperature bath at 40 ° C. 100 μl of the sample solution is injected therein and measurement is performed. The molecular weight of the sample is calculated based on a calibration curve prepared in advance. For the calibration curve at this time, a sample prepared using several types of monodisperse polystyrene as a standard sample is used.
Measuring device: CO-8010 (manufactured by Tosoh Corporation)
Analysis column: GMHLX + G3000HXL (manufactured by Tosoh Corporation)

[Dispersed particle size of resin]
(1) Measuring device: Laser diffraction type particle size measuring machine (LA-920, manufactured by HORIBA, Ltd.)
(2) Measurement conditions: Distilled water is added to the measurement cell, and the volume-median particle size (D ₅₀ ) is measured at a temperature at which the absorbance is in an appropriate range.

[Toner particle size]
(1) Preparation of dispersion: 10 mg of a measurement sample was added to 5 ml of a dispersion [Emulgen 109P (manufactured by Kao Corporation, polyoxyethylene lauryl ether, HLB: 13.6) 5 wt% aqueous solution], and an ultrasonic disperser was used. Disperse for 1 minute, and then add 25 ml of electrolyte [Isoton II (manufactured by Beckman Coulter)] and further disperse for 1 minute with an ultrasonic disperser to obtain a dispersion.
(2) Measuring device: Coulter Multisizer II (Beckman Coulter, Inc.)
Aperture diameter: 50 μm
Measurement particle size range: 1-20 μm
Analysis software: Coulter Multisizer AccuComp version 1.19 (Beckman Coulter)
(3) Measurement conditions: 100 ml of electrolyte solution and dispersion were added to a beaker, and the volume median particle size (D ₅₀ ) of 30,000 particles at a concentration at which the particle size of 30,000 particles could be measured in 20 seconds. Ask for.

Production Example 1 Production of Polyester Resin A Polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane 8320 g, polyoxyethylene (2.0) -2,2-bis (4-hydroxyphenyl) ) 80 g of propane, 1592 g of terephthalic acid and 32 g of dibutyltin oxide (esterification catalyst) were reacted at 230 ° C. under normal pressure for 5 hours under a nitrogen atmosphere, and further reacted under reduced pressure. After cooling to 210 ° C., 1672 g of fumaric acid and 8 g of hydroquinone were added and reacted for 5 hours, and further reacted under reduced pressure to obtain polyester resin A. Polyester resin A had a softening point of 110 ° C., a glass transition point of 66 ° C., an acid value of 24.4 mgKOH / g, and a number average molecular weight of 3760.

Production Example 2 Production of Polyester Resin B 17500 g of polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, polyoxyethylene (2.0) -2,2-bis (4-hydroxyphenyl) ) 16250 g of propane, 11454 g of terephthalic acid, 1608 g of dodecenyl succinic anhydride, 4800 g of trimellitic anhydride and 15 g of dibutyltin oxide are placed in a four-necked flask equipped with a nitrogen introducing tube, a dehydrating tube, a stirrer and a thermocouple, and a nitrogen atmosphere Below, it stirred at 220 degreeC and made it react until the softening point measured based on ASTM D36-86 reached 120 degreeC, and the polyester resin B was obtained. Polyester resin B had a softening point of 123 ° C., a glass transition temperature of 65 ° C., an acid value of 21.0 mgKOH / g, and a number average molecular weight of 2230.

Production Example 3 Production of Polyester Resin C Polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane (34090 g), fumaric acid (5800 g) and dibutyltin oxide (15 g) were introduced into a nitrogen inlet tube, dehydration tube, stirrer and It was put into a four-necked flask equipped with a thermocouple, stirred at 230 ° C. in a nitrogen atmosphere, and reacted until the softening point measured according to ASTM D36-86 reached 100 ° C. to obtain polyester resin C. . Polyester resin Resin C had a softening point of 98 ° C., a glass transition point of 56 ° C., an acid value of 22.4 mgKOH / g, and a number average molecular weight of 2930.

Production Example 4 Production of Masterbatch A 70 parts by weight of fine powder of polyester resin C of Production Example 3 and Pigment Yellow 74 slurry pigment (solid content 47.5%) manufactured by Dainichi Seika Kogyo Co., Ltd. are 30 parts by weight of pigment. In the same manner, it was charged in a hensil mixer and mixed for 5 minutes to wet. Next, this mixture was charged into a kneader mixer and gradually heated. The resin melted at approximately 90 to 110 ° C. and kneaded in a state where water was mixed, and kneading was continued at 90 to 110 ° C. for 20 minutes while water was evaporated.
Further, the kneading was continued at 120 ° C. to evaporate the remaining water, followed by dehydration drying. Further, kneading was continued at 120 to 130 ° C. for 10 minutes. After cooling, the mixture was further kneaded with a heated three roll, cooled and coarsely crushed to obtain a crushed product (master batch A) of a highly concentrated colored composition containing a yellow pigment at a concentration of 30% by weight. When this was placed on a slide glass, heated and melted, and observed with a microscope, all pigment particles were finely dispersed, and no coarse particles were observed.

Production Example 5 Production of Masterbatch B Production was carried out in the same manner as in Production Example 4 except that Pigment Yellow 74 slurry pigment manufactured by Dainichi Seika Kogyo Co., Ltd. was replaced with BASF Pigment Yellow 185 slurry pigment (solid content 41.4%). Thus, a coarsely pulverized product (masterbatch B) of a highly concentrated colored composition containing a yellow pigment at a concentration of 30% by weight was obtained.

Production Example 6 Manufacture of Masterbatch C Manufactured in the same manner as in Production Example 4 except that Pigment Yellow 74 slurry pigment manufactured by Dainichi Seika Kogyo Co., Ltd. was changed to Pigment Yellow 180 slurry pigment (solid content 46.9%) manufactured by Client Corporation. Then, a coarsely pulverized product (masterbatch C) of a highly concentrated colored composition containing a yellow pigment at a concentration of 30% by weight was obtained.

Production Example 7 Production of Master Batch D Same as Production Example 4 except that Pigment Yellow 74 slurry pigment manufactured by Dainichi Seika Kogyo Co., Ltd. was changed to Pigment Yellow 151 slurry pigment (solid content 46.7%) manufactured by Dainichi Seika Kogyo Co., Ltd. Thus, a coarsely pulverized product (masterbatch D) of a highly concentrated colored composition containing a yellow pigment at a concentration of 30% by weight was obtained.

Production Example 8 Production of Master Batch E Same as Production Example 4 except that Pigment Yellow 74 slurry pigment manufactured by Dainichi Seika Kogyo Co., Ltd. was changed to Pigment Yellow 17 slurry pigment (solid content 46.9%) manufactured by Dainichi Seika Kogyo Co., Ltd. Thus, a coarsely pulverized product (masterbatch E) of a highly concentrated colored composition containing a yellow pigment at a concentration of 30% by weight was obtained.

Example 1
In a 5 liter stainless steel kettle, 319.8 g of resin A, 210.0 g of resin B, 100.20 g of masterbatch A, and nonionic surfactant “Emulgen 430 (manufactured by Kao)” polyoxyethylene oleyl ether (HLB: 16.2) ) 6.0 g, anionic surfactant “Neopelex G-25 (manufactured by Kao)” 24.0 g of sodium dodecylbenzenesulfonate and 252.0 g of potassium hydroxide aqueous solution (concentration: 5% by weight) as a neutralizing agent In addition, the pH was adjusted to 6.2 and dispersed at 95 ° C. with stirring at 250 r / min with a chi-type stirrer. The contents were stirred for 2 hours after reaching 95 ° C., and then 1120 g of deionized water was added dropwise over 150 minutes with stirring at 200 r / min with a chi-type stirrer, and 200 mesh (opening: 105 μm). A fine colorant-containing resin dispersion A was obtained through a wire mesh. The volume median particle size of the resin particles in the obtained resin dispersion was 0.142 μm, the solid content concentration was 35.8% by weight, and no resin component remained on the wire mesh.

  Under a stirring of 100 r / min with a Kai-type stirrer, 400 g of the colorant-containing resin dispersion A charged in a 2 liter container was added to the dispersion with 6.1 g of ammonium sulfate (molecular weight: 132.14) as a flocculant. Dissolved in ionic water, the aqueous solution was added dropwise at room temperature over 15 minutes. Thereafter, the mixed dispersion was heated at 1 ° C./5 min to form aggregated particles. When the temperature reached 85 ° C., the mixture was fixed at 85 ° C. and stirred for 2 hours, and then the heating was stopped. In these 2 hours, the toner shape changed from aggregated particles to coalesced particles. The solid content concentration when the volume median particle size of the aggregated particles reached 3 μm was 24% by weight. The solid content was measured with an infrared moisture meter (FD-230, manufactured by Kett Science Laboratory).

The solution was gradually cooled to room temperature, and colored resin fine particle powder was obtained through a suction filtration step, a washing step and a drying step. The volume median particle size (D50) of the colored resin fine particle powder was 3.9 μm and had a single peak particle size distribution.
To 100 parts by weight of the colored fine resin particle powder, 1.0 part by weight of hydrophobic silica (manufactured by Wacker Chemie, TS530, number average primary particle size: 8 nm) was externally added using a Henschel mixer to obtain a yellow toner. With the obtained yellow toner, a good image was obtained with a commercially available full color printer.

Reference Example Coloring is performed in the same manner as in Example 1 of the colorant-containing resin dispersion except that it is changed to 390.0 g of resin A, 210.0 g of resin B, and 30 g of Pigment Yellow 74 manufactured by Dainichi Seika Kogyo Co., Ltd. An agent-containing resin dispersion F was prepared. The resin particles in the obtained resin dispersion had a volume median particle size of 0.284 μm, a solid concentration of 30.4% by weight, and 1.2 g of the resin component remained on the wire mesh.
Combined particles were produced in the same manner as in Example 1 except that the colorant-containing resin dispersion A was changed to the colorant-containing resin dispersion F. The solid content concentration when the volume-median particle diameter of the aggregated particles reached 3 μm was 23% by weight.
The solution was gradually cooled to room temperature, and colored resin fine particle powder was obtained through a suction filtration step, a washing step and a drying step. The volume median particle size (D50) of the colored resin fine particle powder was 3.7 μm, which was a single peak particle size distribution.
1.0 part by weight of hydrophobic silica (TS530 manufactured by Wacker Chemie, primary number average particle diameter: 8 nm) is externally added to 100 parts by weight of the colored resin fine particle powder using a Henschel mixer to obtain a yellow toner. With the obtained yellow toner, a good image was obtained with a commercially available full color printer.

Comparative Example 1
A colorant-containing resin dispersion B was prepared in the same manner as in Example 1 except that the master batch A was changed to the master batch B. The resin particles in the obtained resin dispersion had a volume-median particle size of 0.312 μm, a solid content concentration of 30.8% by weight, and 15.8 g of the resin component remained on the wire mesh.
Toner particles were produced in the same manner as in Example 1, except that the colorant-containing resin dispersion A in Example 1 was changed to the colorant-containing resin dispersion B. The volume median particle size (D50) of the colored resin fine particle powder was 9.2 μm, and the particle size distribution was bimodal. The solid content concentration when the volume median particle size of the aggregated particles reached 3 μm was 22% by weight. In addition, yellow pigments were preferentially agglomerated in toner particles aggregated preferentially and toner particles that were mostly polyester, and the color was also orange.

Comparative Example 2
The production of the colorant-containing resin dispersion C was attempted in the same manner as in Example 1 except that the masterbatch A was changed to the masterbatch C. However, most of the pigment and resin remained on the wire mesh, and the colorant-containing resin. Dispersion C could not be prepared.

Comparative Example 3
Except for changing the master batch A to the master batch D, an attempt was made to prepare the colorant-containing resin dispersion D in the same manner as in Example 1. However, most of the pigments and resins remained on the wire mesh and the colorant-containing resin was used. Dispersion D could not be prepared.

Comparative Example 4
A colorant-containing resin dispersion E was prepared in the same manner as in Example 1 except that the master batch A was changed to the master batch E. The resin particles in the obtained resin dispersion had a volume median particle size of 0.222 μm and a solid concentration of 32.0% by weight, and 1.8 g of the resin component remained on the wire mesh.

Toner particles were produced in the same manner as in Example 1, except that the colorant-containing resin dispersion A in Example 1 was changed to the colorant-containing resin dispersion E. When the temperature reached 85 ° C., the mixture was fixed at 85 ° C. and stirred for 2 hours, and then the heating was stopped. In these 2 hours, the toner shape changed from aggregated particles to coalesced particles. When the volume median particle size of the aggregated particles became 3 μm, the solid content concentration was 25% by weight.
The solution was gradually cooled to room temperature, and colored resin fine particle powder was obtained through a suction filtration step, a washing step and a drying step. The volume median particle size (D50) of the colored resin fine particle powder was 7.9 μm, and the particle size distribution became bimodal. In addition, yellow pigments were preferentially distributed in toner particles preferentially aggregated and toner particles that were mostly polyester.
1.0 part by weight of hydrophobic silica (manufactured by Wacker Chemie, TS530, primary number average particle diameter: 8 nm) per 100 parts by weight of the colored resin fine particle powder was externally added using a Henschel mixer to obtain a yellow toner. . The obtained yellow toner was found to be unsuitable as a toner because of a lot of image fogging in a commercially available full color printer.

  The results of the above examples and comparative examples are shown in Table 1 below. Moreover, each evaluation of alkali resistance, emulsification property, and aggregability was performed on the following reference | standard.

<Alkali resistance evaluation>
A: When an alkali is added, a yellow hue change cannot be confirmed by visual evaluation.
○: When an alkali is added, a slight yellow hue change is visually observed, but it is recognized as yellow.
X: When an alkali is added, a yellow hue change can be confirmed by visual evaluation (red change), and is recognized as orange.

<Emulsification>
A: After emulsification, when passing through a 200 mesh (mesh: 105 μm) wire mesh, no coarse particles remain on the wire mesh.
○: After emulsification, when passing through a 200 mesh (mesh: 105 μm) wire mesh, less than 2 g of coarse particles remain.
X: After emulsification, when passing through a 200 mesh (mesh: 105 μm) wire mesh, 2 g or more of coarse particles remain or cannot be emulsified.

<Cohesiveness>
A: Agglomerated particles having a single peak in particle size distribution and no coloring unevenness are formed.
Δ: The particle size distribution has a single peak, but uneven coloring is observed in the aggregated particles.
X: The particle size distribution does not have a single peak, and marked coloring unevenness is confirmed in the aggregated particles.
-: Since the emulsification was not possible, the aggregation process was not reached.

  The method for producing a yellow toner of the present invention can control the toner particle size easily and in a short production time without substantially using an organic solvent, and also suppresses reddening. Can be suitably used for the production of yellow toners such as a method, an electrostatic recording method, and an electrostatic printing method.

Claims (9)

  (1) a step of dispersing Color Index Pigment Yellow 74 (Pigment Yellow 74) in a molten binder resin containing polyester, and (2) the above-mentioned bond containing Pigment Yellow 74 in an aqueous medium in the presence of alkali. A process for producing emulsified particles of a resin.   The method for producing a yellow toner according to claim 1, wherein the ratio of the binder resin and pigment yellow 74 used in step (1) is 60:40 to 97: 3 by weight.   The method for producing a yellow toner according to claim 1 or 2, wherein the emulsification in the step (2) is performed at a temperature equal to or higher than a glass transition point of the polyester in the binder resin.   The method for producing a yellow toner according to any one of claims 1 to 3, wherein an alkali is present in the step (2) so that the pH value of the emulsion of the dispersion is 5.6 to 8.0.   The method for producing a yellow toner according to claim 1, wherein the emulsified particles have a volume-median particle size of 0.05 to 0.8 μm.   The method for producing a yellow toner according to claim 1, further comprising: (3) a step of aggregating the emulsified particles of the binder resin containing Pigment Yellow 74 in an aqueous medium.   The method for producing a yellow toner according to claim 6, wherein the solid content concentration in the step (3) is 15 to 40% by weight when the volume-median particle size of the aggregated particles becomes 3 µm.   The method for producing a yellow toner according to claim 1, wherein the polyester has an acid value of 6 to 35 mg KOH / g.   Step (1) is a process of melting and kneading a pigment yellow 74 press cake or aqueous paste and a resin to transfer the aqueous phase pigment yellow 74 to the resin phase and removing moisture, thereby removing the melted polyester-containing molten bond. The method for producing a yellow toner according to any one of claims 1 to 8, which is a step of dispersing Pigment Yellow 74 in a resin.