JP5111956B2 - Resin emulsion - Google Patents

Description

  The present invention relates to a resin emulsion used for electrophotography, electrostatic recording, electrostatic printing, and the like, an electrophotographic toner obtained from the resin emulsion, and a method for producing the same.

In the field of toner for electrophotography, development of a small particle size toner excellent in fixability is desired from the pursuit of high image quality. The toner production method includes a melt kneading pulverization method and a wet production method such as an emulsion aggregation method. In these methods, for example, toner particles are obtained using a binder resin mainly composed of polyester.
Conventionally, as a crosslinking component used in preparing a crosslinked polyester used as a binder resin, a trivalent or higher polyvalent carboxylic acid such as trimellitic acid may be used. For example, Patent Document 1 discloses an aromatic dicarboxylic acid component selected from isophthalic acid, terephthalic acid, and derivatives thereof, an aromatic tricarboxylic acid component selected from trimellitic acid and derivatives thereof, dodecenyl succinic acid, and octyl succinic acid. And a toner using a polyester formed from a monomer composition consisting of a dicarboxylic acid component selected from its anhydride and a propoxylated and / or ethoxylated etherified diphenol component.

JP-A-6-19204

However, in the crosslinked polyester using trimellitic acid which is a trivalent or higher polyvalent carboxylic acid as described above or a derivative thereof, it is difficult to prepare an emulsion by phase inversion emulsification. There was a problem in that the resin was hydrolyzed by alkali and a significant decrease in thermal properties was observed.
The present invention provides a resin emulsion that can be easily emulsified even when a crosslinked polyester is used, hardly causes hydrolysis of the resin, and can provide a toner having excellent heat-resistant storage stability, a method for producing the same, and the resin The present invention relates to an electrophotographic toner excellent in heat-resistant storage obtained using an emulsion and a method for producing the same.

The present invention
(1) A resin emulsion obtained by neutralizing a binder resin having an acid group with a basic compound in an aqueous medium, wherein the binder resin having an acid group is a trihydric or higher polyhydric alcohol A resin emulsion containing a polyester obtained from a raw material monomer containing 1 to 15 mol%,
(2) A method for producing a resin emulsion comprising a step of neutralizing a binder resin having an acid group with a basic compound in an aqueous medium, wherein the binder resin contains a trihydric or higher polyhydric alcohol. A method for producing a resin emulsion, comprising polyester obtained from raw material monomers containing ˜15 mol%,

(3) Toner for electrophotography obtained by aggregating and coalescing resin emulsion particles in the resin emulsion according to (1) above, and (4) (a) a polyhydric alcohol having a valence of 3 or more in an aqueous medium. And (b) a resin obtained by neutralizing a binder resin containing a polyester obtained from a raw material monomer containing 1 to 15 mol% and having an acid group with a basic compound to obtain a resin emulsion. A process for aggregating and coalescing resin emulsified particles in an emulsion, and a method for producing an electrophotographic toner,
About.

  According to the resin emulsion of the present invention, it is possible to obtain an electrophotographic toner that is easily emulsified even when a crosslinked polyester is used, hardly undergoes hydrolysis of the resin, and is excellent in heat-resistant storage stability.

Hereinafter, the resin emulsion of the present invention and the production method thereof will be described.
[Binder resin having acid groups]
The binder resin having an acid group (hereinafter sometimes simply referred to as “binder resin”) is a resin used as a binder resin in a toner, and is a known resin used in a toner, such as polyester, styrene- Acrylic copolymers, epoxy resins, polycarbonates, polyurethanes, etc. can be used. Among these, polyester or styrene-acrylic copolymer is preferable, and polyester is more preferable from the viewpoints of colorant dispersibility, fixability, and durability. The content of the polyester in the binder resin is preferably 60% by weight or more, more preferably 70% by weight or more, more preferably 80% by weight or more, and further preferably 90% by weight or more. In the present invention, the above resins may be used alone as a binder resin, but may be used in combination of two or more.
When the resin having an acid group contains polyester, it may be either crystalline polyester or amorphous polyester.

As a raw material monomer for polyester, a known divalent or higher valent alcohol component and a known carboxylic acid component such as a divalent or higher carboxylic acid, carboxylic acid anhydride, or carboxylic acid ester are used.
Specifically, the alcohol component includes ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1, Aliphatic diols such as 7-heptanediol, 1,8-octanediol, neopentyl glycol, 1,4-butenediol: Formula (1):

(In the formula, RO is an alkylene oxide, R is an alkylene group having 2 or 3 carbon atoms, x and y are positive numbers indicating the average number of added moles of alkylene oxide, and the sum of x and y is 1-16. , Preferably 1 to 8, and more preferably 1.5 to 5). An aromatic diol such as an alkylene oxide adduct of bisphenol A; trivalent or more such as glycerin, pentaerythritol, trimethylolpropane, sorbitol And polyhydric alcohols. These alcohol components may be used individually by 1 type, and may be used in combination of 2 or more type.

  Polyester is obtained by a condensation polymerization reaction from the above-mentioned alcohol component as a raw material monomer and a carboxylic acid component described later. In the present invention, from the viewpoint of fixability, storage stability, emulsification property, and hydrolysis resistance, all raw materials are used. The monomer component contains 1 to 15 mol% of a trihydric or higher polyhydric alcohol. In general, when a crosslinked polyester is prepared, if a trivalent or higher polyvalent carboxylic acid such as trimellitic acid or a derivative thereof is used, neutralization may not be sufficiently performed during resin emulsification. In some cases, the hydrolysis of the polyester may be caused by the presence of an acid group in the vicinity of the rigid crosslinking point of the polyester. On the other hand, when a polyhydric alcohol having a valence of 3 or more is used as a crosslinking component as in the present invention, acid groups are likely to be present at the ends of the main chain rather than near the center of the crosslinking, It is considered that the resin is neutralized efficiently by the basic compound, and as a result, the resin emulsion can be easily prepared. In this invention, since a basic compound is effectively used for neutralization in this way, it is estimated that hydrolysis by a basic compound is suppressed.

  The trihydric or higher polyhydric alcohol used in the present invention is preferably a 3-6 valent polyhydric aliphatic alcohol, more preferably from the viewpoint of effectively neutralizing and suppressing the hydrolysis of the polyester. Is glycerin, pentaerythritol, trimethylolpropane, or sorbitol, more preferably glycerin. These may be used individually by 1 type and may be used in combination of 2 or more type. In the present invention, the polyhydric aliphatic alcohol may include a polyalicyclic alcohol such as 1,4-sorbitan.

  The trihydric or higher polyhydric alcohol is contained in 1 to 15 mol% in all raw material monomers including an alcohol component and an acid component. If the content is 1 mol% or more, the polyhydric alcohol is added. The required softening point and high molecular weight part as a crosslinked resin can be obtained. Moreover, if it is 15 mol% or less, high-density crosslinking can be prevented, generation of hydrolysis of the resin in the neutralization step, and prevention of incomplete emulsification due to the progress of neutralization can be prevented. it can. From the above viewpoint, the trihydric or higher polyhydric alcohol is preferably 1.5 to 14 mol%, more preferably 1.5 to 13 mol%, still more preferably 1.5 to 10 mol% in all raw material monomers. is there.

  When the polyester is an amorphous polyester, the alcohol component of the amorphous polyester includes polyoxypropylene-2,2-bis (4-hydroxyphenyl) propane, polyoxyethylene together with the trihydric or higher polyhydric alcohol. It is represented by the above formula (I) such as alkylene (2 to 3 carbon) oxide (average added mole number 1 to 16) adduct of bisphenol A such as -2,2-bis (4-hydroxyphenyl) propane. It is preferable that an alkylene oxide adduct of bisphenol A is contained.

  As carboxylic acid components, oxalic acid, malonic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, n-dodecyl succinic acid, n-dodecenyl succinic acid, etc. Aliphatic dicarboxylic acids such as cyclohexanedicarboxylic acid; Aromatic dicarboxylic acids such as phthalic acid, isophthalic acid and terephthalic acid; Trimellitic acid; Trivalent or higher polyvalent carboxylic acids such as pyromellitic acid; And anhydrides of these acids, alkyl (carbon number 1 to 3) esters, and the like. These may be used individually by 1 type and may be used in combination of 2 or more type.

Polyester can be produced, for example, by polycondensing the alcohol component and the carboxylic acid component in an inert gas atmosphere at a temperature of 180 to 250 ° C. using a known esterification catalyst as necessary. it can.
The above polyesters can be used alone as a binder resin, but can also be used in combination of two or more.

Polyester has a softening point of preferably from 80 to 165 ° C, more preferably from 95 to 160 ° C, and a glass transition point of from 50 to 85 ° C, more preferably from 50 to 75 ° C, from the viewpoint of toner storage stability. The acid value is preferably 6 to 30 mgKOH / g, more preferably 6.5 to 29 mgKOH / g, and still more preferably, in order to stabilize the emulsified particles and to obtain a small particle size toner with a sharp particle size distribution. It is 7 to 28 mgKOH / g, and the hydroxyl value is preferably 3 to 60 mgKOH / g. In the present invention, polyester having at least one of the above properties is preferably used. The desired softening point and acid value can be obtained by adjusting the raw material monomer composition of the reaction conditions such as the condensation polymerization temperature and reaction time.
The weight average molecular weight of the polyester is preferably 5,000 to 150,000, more preferably 10,000 to 120,000, from the viewpoint of durability and fixability, and the number average molecular weight is 1,000 to 100,000 are preferred, 1,000 to 50,000 are more preferred, and 1,000 to 12,000 are even more preferred.

  The binder resin in the present invention has an acid group, and particularly preferably has an acid group at the molecular chain terminal. Examples of the acid group include a carboxyl group, a sulfonic acid group, a phosphonic acid group, a sulfinic acid group, and the like, and a carboxyl group is preferable from the viewpoint of achieving both the emulsifiability of the resin and the environmental resistance characteristics of the toner using the resin. The amount of the acid group at the molecular chain terminal of the binder resin having an acid group is one of important factors that determine the stability of the emulsified particles and the particle size distribution and particle size of the toner. In order to stabilize the emulsified particles and obtain a toner having a small particle size with a sharp particle size distribution, the acid value of the binder resin is preferably 6 to 30 mgKOH / g, more preferably 6.5 to 29 mgKOH / g, and 7 to More preferred is 28 mg KOH / g.

  Further, from the viewpoint of dispersing the resin particles quickly and uniformly, as the binder resin having an acid group, resin particles having a particle size through which a sieve having an opening diameter of 5.6 mm passes through 95% by weight or more and further 98% by weight or more are used. It is preferable. By using resin particles having such a particle size, they can be dispersed uniformly, and in the next neutralization step, uniform neutralization is possible, and homogeneous emulsified particles can be produced.

  From the same viewpoint as in the case of polyester, the softening point of the binder resin is preferably 80 to 165 ° C, and the glass transition point is preferably 50 to 85 ° C. The weight average molecular weight and number average molecular weight of the binder resin are preferably the same values as those of the polyester. When the binder resin contains a plurality of resins, the average molecular weight, softening point, glass transition point and acid value of the binder resin all mean values as a mixture of the binder resins.

[Resin emulsion and method for producing the same]
The resin emulsion of the present invention is obtained by neutralizing the binder resin having an acid group with a basic compound in an aqueous medium.
The aqueous medium contains water as a main component, and from the viewpoint of environmental conservation, the water content is preferably 80% by weight or more, more preferably 90% by weight or more, and even more preferably 100% by weight in the aqueous medium. . In the present invention, the binder resin can be dispersed by using only water without substantially using an organic solvent. Examples of components other than water include organic solvents that dissolve in water, such as methanol, ethanol, isopropanol, butanol, acetone, methyl ethyl ketone, and tetrahydrofuran. Among these, alcohol-based organic solvents such as methanol, ethanol, isopropanol, butanol and the like, which are organic solvents that do not dissolve the resin, are preferable from the viewpoint of preventing mixing into the toner.

  As a basic compound, any of an inorganic basic compound and an organic basic compound may be sufficient. Examples of the inorganic basic compound include alkali metal hydroxides such as sodium hydroxide, potassium hydroxide and lithium hydroxide, weak acid salts such as carbonates and acetates thereof, partially neutralized salts, and ammonia. . Examples of the organic basic compound include alkylamines such as methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine and triethylamine, alkanolamines such as diethanolamine, and fatty acid salts such as sodium succinate and sodium stearate. These basic compounds may be used individually by 1 type, and may be used in combination of 2 or more type.

The basic compound can be used as a basic aqueous medium, and the content of the basic compound in the basic aqueous medium depends on the type of the basic compound to be used. From the point of suppression, it is 1-30 weight% normally, Preferably it is 3-20 weight%, More preferably, it is 5-10 weight%. As the aqueous medium for the basic aqueous medium, the same aqueous medium as that described above can be used.
The amount of the basic aqueous medium used is preferably 5 to 100 parts by weight with respect to 100 parts by weight of the binder resin having an acid group, from the viewpoint that a uniform resin emulsion can be effectively prepared. Part by weight is more preferable, and 20 to 80 parts by weight is further preferable.

The resin emulsion of the present invention is obtained by dispersing a resin having an acid group in an aqueous medium, neutralizing the obtained dispersion at a temperature below the softening point of the resin, and then adding an aqueous liquid. It can be obtained by emulsifying the resin in a medium.
In the present invention, a surfactant can be added during the dispersion treatment. The addition amount is preferably 5% by weight or less, more preferably 0.2% with respect to the resin for the purpose of suppressing foaming in the dispersion step and improving the emulsion stability of the finally obtained resin emulsion. -5% by weight, more preferably 0.5-4% by weight, still more preferably 1-3% by weight.

  Examples of the surfactant include anionic surfactants such as sodium dodecylbenzenesulfonate, sodium octadecyl sulfate, sodium oleate, sodium laurate, and potassium stearate; laurylamine acetate, stearylamine acetate, lauryltrimethylammonium chloride, and the like. Cationic surfactants such as: Amphoteric surfactants such as lauryl dimethylamine oxide; Nonionic surfactants such as polyoxyethylene alkyl ether, polyoxyethylene alkyl phenyl ether, sorbitan monostearate, and polyoxyethylene alkyl amine It is done. Among these, anionic surfactants and nonionic surfactants are preferable from the viewpoint of emulsion stability and the like, and anionic surfactants are more preferable. These surfactants may be used individually by 1 type, and may be used in combination of 2 or more type.

Moreover, a colorant can be added to the binder resin, and additives such as a release agent and a charge control agent can be added as necessary, and the mixture can be dispersed.
The colorant is not particularly limited, and any known colorant can be used and can be appropriately selected. Specifically, carbon black, inorganic composite oxide, chrome yellow, hansa yellow, benzidine yellow, selenium yellow, quinoline yellow, permanent orange GTR, pyrazolone orange, vulcan orange, watch young red, permanent red, brilliantamine 3B, Brilliantamine 6B, Dupont Oil Red, Pyrazolone Red, Resol Red, Rhodamine B Lake, Lake Red C, Bengal, Aniline Blue, Ultramarine Blue, Calco Oil Blue, Methylene Blue Chloride, Phthalocyanine Blue, Phthalocyanine Green, Malachite Green Oxalate, etc. Various pigments, acridine, xanthene, azo, benzoquinone, azine, anthraquinone, indico, thioi Zico system, phthalocyanine, aniline black, can be used alone or in combination of two or more kinds of various dyes of thiazole, and the like.

The use ratio of the binder resin and the colorant is preferably 70:30 to 97: 3, and more preferably 80:20 to 97: 3, in terms of weight ratio, from the viewpoints of toner chargeability, durability, print density, and the like. .
Specific examples of the release agent include low molecular weight polyolefins such as polyethylene, polypropylene and polybutene; silicones having a softening point by heating; fatty acid amides such as oleic acid amide, erucic acid amide, ricinoleic acid amide and stearic acid amide ; Plant waxes such as carnauba wax, rice wax, candelilla wax, tree wax, jojoba oil; animal waxes such as beeswax; minerals such as montan wax, ozokerite, ceresin, paraffin wax, microcrystalline wax, Fischer-Tropsch wax・ Petroleum-based wax.

The content of the release agent is usually about 1 to 20 parts by weight, preferably 2 to 100 parts by weight with respect to the total amount of the binder resin and the colorant in consideration of the addition effect and the adverse effect on the chargeability. 15 parts by weight.
Examples of charge control agents include benzoic acid metal salts, salicylic acid metal salts, alkyl salicylic acid metal salts, catechol metal salts, metal-containing bisazo dyes, tetraphenylborate derivatives, quaternary ammonium salts, alkylpyridinium salts, and the like. Can be mentioned. These may be used individually by 1 type and may be used in combination of 2 or more type.
The content of the charge control agent is usually 10 parts by weight or less, preferably 0.01 to 5 parts by weight with respect to 100 parts by weight of the total amount of the binder resin and the colorant.

The dispersion treatment is performed at a temperature lower than the softening point of the resin particles from the viewpoint of uniformly dispersing the resin particles or a mixture of these and various additives. By performing a dispersion treatment at a temperature lower than the softening point of the resin particles, preferably 50 ° C. lower than the softening point (hereinafter referred to as “softening point−50 ° C.”), the fusion between the resin particles is suppressed, A uniform resin dispersion can be prepared. Further, the lower limit temperature of the dispersion treatment is preferably higher than 0 ° C., more preferably 10 ° C. or higher, from the viewpoint of fluidity of the medium and production energy of the resin emulsion. When using a mixed 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.
Specifically, in a basic aqueous medium containing a surfactant, resin particles having an acid group such as polyester, together with a colorant and the like, at a temperature below the softening point of the resin particles, for example, at a temperature of about 10 to 50 ° C. A uniform resin dispersion can be prepared by an ordinary method such as stirring for dispersion treatment.

In the present invention, the obtained resin dispersion is neutralized with the basic compound. Neutralization is preferably carried out with stirring for a certain period of time at a temperature below the softening point of the resin, more preferably below the softening point of the resin and above the glass transition point of the resin. From the viewpoint of uniformly neutralizing the resin, the stirring time is preferably 30 minutes or longer, more preferably 1 hour or longer.
By performing the neutralization at a temperature within the above range, the neutralization is sufficiently performed, the generation of large emulsified particles is suppressed by the emulsification treatment in the next step, and no special apparatus is required for heating. In this respect, the neutralization temperature is preferably a glass transition point of the resin + 10 ° C or higher, and is preferably a softening point of -5 ° C or lower.
Furthermore, from the viewpoint of inhibiting hydrolysis, neutralization is more preferably performed near normal pressure. Specifically, 80 to 300 kPa is preferable, and 100 to 200 kPa is more preferable.

  The degree of neutralization in this neutralization step may be such that hydrophilicity necessary for producing emulsified particles in the next step can be imparted to the resin, and it is not always necessary to neutralize 100%. For example, when a highly hydrophilic resin having many polar groups is used, the degree of neutralization may be low. Conversely, when a resin having low hydrophilicity is used, it is preferable to increase the degree of neutralization. In the present invention, the degree of neutralization is preferably 50% or more, more preferably 60 to 100%, and still more preferably 70 to 100%. The degree of neutralization can generally be represented by the ratio of the number of moles of acid groups before and after neutralization (number of moles of acid groups after neutralization / number of moles of acid groups before neutralization).

  Specifically, the resin dispersion is stirred at a temperature equal to or lower than the softening point of the resin, preferably above the glass transition point, for example, a carboxyl having a glass transition point of about 60 to 65 ° C. and a softening point of about 110 to 120 ° C. When the polyester having a group is used, the temperature is raised to a temperature of about 90 to 100 ° C., and neutralization is performed by maintaining the temperature for a suitable time until a predetermined degree of neutralization is reached.

The neutralized dispersion is emulsified in an aqueous medium by adding an aqueous liquid at a temperature not lower than the glass transition point and not higher than the softening point of the resin.
In this emulsification step, from the viewpoint of preparing a fine resin emulsion, the neutralized resin dispersion is maintained at a temperature not lower than the glass transition point and not higher than the softening point of the resin and stirred while being aqueous. It is preferable to add a liquid and emulsify in an aqueous medium.
In addition, by performing the emulsification at a temperature within the above range, the emulsification is performed smoothly and no special apparatus is required for heating. From this, the temperature at the time of emulsification is preferably a temperature of glass transition point + 10 ° C. or higher, and a temperature of softening point −5 ° C. or lower is preferable.

In this emulsification step, the resin content in the dispersion is preferably about 50 to 90% by weight, more preferably 50 to 80% by weight, from the viewpoint of easy phase inversion immediately before the start of emulsification. Here, “immediately before the start of emulsification” refers to a point in time when the viscosity of the system becomes the highest in all the steps. Therefore, by attaching a torque meter or the like to the stirrer, the point in time can be easily known.
The emulsification start time can be arbitrarily adjusted depending on the acid value and the degree of neutralization of the resin used. For example, when the acid value of the resin is increased or the degree of neutralization is increased, the hydrophilicity of the resin is increased, and emulsification can be started by contacting with a small amount of an aqueous medium.

Examples of the aqueous liquid used for emulsification include the same ones as the aqueous medium. The addition rate of the aqueous liquid is preferably 0.5 to 50 g / min, more preferably 0.5 to 30 g / min, and further preferably 1 to 20 g per 100 g of resin from the viewpoint that emulsification can be effectively carried out. / Min. In general, the addition rate may be maintained until the O / W type emulsion is substantially formed, and the addition rate of the aqueous liquid after the formation of the O / W type emulsion is not particularly limited.
The solid content concentration of the resin emulsion thus obtained is preferably 7 to 50% by weight from the viewpoint of the stability of the emulsion and the handleability of the resin emulsion in the subsequent aggregation step. -45 wt% is more preferable, and 10-40 wt% is more preferable.

Further, the volume median particle size (D ₅₀ ) of the emulsified particles after forming the O / W type emulsion is preferably 0.02 to 2 μm, more preferably in order to perform uniform aggregation in the aggregation step. Is 0.05-1 μm, more preferably 0.05-0.6 μm. From the same viewpoint, the particle size distribution is preferably 60 or less, more preferably 45 or less in terms of CV value (standard deviation of particle size distribution / volume average particle size (D ₅₀ ) × 100). In the present specification, the volume-median particle size (D ₅₀ ) means a particle size at which the cumulative volume frequency calculated by the volume fraction is 50% when calculated from the smaller particle size.
The weight average molecular weight of the resin in the resin emulsified particles is preferably 5,000 to 150,000 and preferably 10,000 to 120,000 from the viewpoints of hydrolysis resistance, durability and fixability. More preferred.

  The present invention is also a method for producing a resin emulsion comprising a step of neutralizing a binder resin having an acid group with a basic compound in an aqueous medium, wherein the binder resin is a trivalent or higher polyvalent. The present invention relates to a method for producing a resin emulsion containing polyester obtained from a raw material monomer containing 1 to 15 mol% of alcohol. The aqueous medium, the binder resin having an acid group, the neutralization step and the like in the production method are as described in the explanation of the resin emulsion.

Hereinafter, the toner for electrophotography and the manufacturing method thereof will be described.
[Electrophotographic toner and method for producing the same]
Next, the emulsified particles in the resin emulsion thus obtained are agglomerated (hereinafter referred to as aggregating step), and further united (hereinafter referred to as a coalescing step), whereby the electrophotographic toner of the present invention. Is obtained. The aggregation and coalescence can be performed in the presence of a colorant, and the colorant may be contained in the resin emulsion, or the dispersion of the colorant is mixed with the resin emulsion to aggregate and coalesce. May be.

In the coagulation 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 cohesiveness of fine particles such as the binder resin and the colorant. 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. .
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 salt weights 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, polymers thereof, 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. These flocculants may be used individually by 1 type, and may be used in combination of 2 or more type.

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).

In the present invention, it is preferable to add a surfactant after aggregating the resin emulsified particles, and at least one selected from the group consisting of alkyl ether sulfates, alkyl sulfates, and linear alkylbenzene sulfonates. More preferably, it is added.
As the alkyl ether sulfate, those represented by the following formula (1) are preferable.
R ¹ —O— (CH ₂ CH ₂ O) pSO ₃ M ¹ (1)
In the formula, R ¹ represents an alkyl group, and preferably an alkyl group having 6 to 20 carbon atoms, more preferably 8 to 15 carbon atoms, from the viewpoint of adsorptivity to aggregated particles and persistence to toner. p represents an average added mole number of 0 to 15, and is preferably 1 to 10, more preferably 1 to 5, from the viewpoint of particle size control. M ¹ represents a monovalent cation, and is preferably sodium, potassium, or ammonium, more preferably sodium or ammonium, from the viewpoint of particle size control.

The linear alkyl benzene sulfonate is not particularly limited, but is preferably a compound represented by the formula (2) from the viewpoint of adsorptivity to aggregated particles and persistence to toner.
R ² -Ph-SO ₃ M ² (2)
In the formula, R ² represents a linear alkyl group, and is the same as the linear ^one of R ^{1 in} the formula (1).
Ph is a phenyl group, and M ² is a monovalent cation. As the linear alkylbenzene sulfonate, sodium sulfate is preferably used.

The amount of the surfactant added is preferably from 0.1 to 15 parts by weight, more preferably from 0.1 to 15 parts by weight, based on 100 parts by weight of the resin constituting the aggregated particles, from the viewpoints of aggregation stopping properties and persistence to the toner. 1 to 10 parts by weight, more preferably 0.1 to 8 parts by weight.
In the present invention, from the viewpoint of improving the image quality, the volume median particle size (D ₅₀ ) of the aggregated particles is preferably 1 to 10 μm, more preferably 2 to 10 μm, and further preferably 2 to 9 μm.

In the present invention, from the viewpoint of preventing the release of a release agent and the like, improving the durability and heat-resistant storage stability, or making the charge amount between colors the same level in a color toner, the present invention Other resin particles are added to the resin particles contained in the resin emulsion (hereinafter sometimes referred to as “resin particles of the present invention”) at one time or divided into a plurality of times, or other resin particles. The resin particles of the present invention can be further aggregated by adding the resin particles of the present invention at one time or divided into a plurality of times to the aggregated particles obtained by adding the coagulant.
There is no restriction | limiting in particular in other resin particles, For example, it can prepare similarly to the resin particle of this invention.
In addition to the binder resin, the other resin particles can appropriately contain additives such as the colorant, the release agent, the charge control agent, and the surfactant and the fixability improver as necessary. .

In the present invention, the other resin particles may be the same as or different from the resin particles of the present invention. From the viewpoint of achieving both low temperature fixability and storage stability of the toner, the present resin particles are preferably used. The resin particles of the present invention are added to the aggregated particles obtained by adding an aggregating agent to the resin particles different from the resin particles of the invention at one time or divided into a plurality of times. Moreover, you may make it mix with the aggregated particle obtained by adding the coagulant | flocculant to the resin particle of this invention.
In the present invention, the addition timing of the resin particles of the present invention is not particularly limited, but from the viewpoint of productivity, it is from the end of addition of the flocculant to other resin particles until the coalescence step. Is preferred.
The blending ratio of the resin particles of the present invention to other resin particles (the resin particles of the present invention / other resin particles) is 0.1 to 2.0 by weight from the viewpoint of achieving both low-temperature fixability and heat-resistant storage stability. Preferably, it is 0.2 to 1.5, more preferably 0.3 to 1.0.

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.

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 appropriate.
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.

The electrophotographic toner of the present invention contains coalesced particles (toner base particles) obtained as described above, and the content of the coalesced particles in the toner is the property of toner chargeability and fixability. From the viewpoint, 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 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 has a CV value of preferably 25 or less, more preferably 20 or less, and still more preferably 18 or less.

  Further, the softening point of the toner is preferably 60 to 140 ° C., more preferably 60 to 130 ° C., and further preferably 60 to 120 ° C. from the viewpoint of low-temperature fixability. Moreover, 30-80 degreeC is preferable from a durable viewpoint, and, as for a glass transition point, 40-70 degreeC is more preferable. From the same viewpoint, the maximum peak temperature of the endotherm by the differential scanning calorimeter is preferably 60 to 140 ° C, more preferably 60 to 130 ° C, and further preferably 60 to 120 ° C.

In the toner 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 electrophotographic toner of the present invention is applied include plain paper and OHP sheets used in electrophotographic copying machines and printers.
The toner for electrophotography obtained by the present invention can be used as a one-component developer or as a two-component developer by mixing with a carrier.

Each property value was measured and evaluated by the following method.
[Acid value of resin]
Measured according to JIS K0070. However, the measurement solvent was changed from a mixed solvent of ethanol and ether to a mixed solvent of acetone and toluene (acetone: toluene = 1: 1 (volume ratio)).
[Softening point and glass transition point of resin and toner]
(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, a load of 1.96 MPa was applied by a plunger, a diameter of 1 mm, Extrude from a 1 mm long nozzle. Plot the flow tester drop by the flow tester against the temperature, and let the softening point be the temperature at which half the sample flowed out.

(2) Glass transition point The temperature was raised 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.

[Weight average molecular weight of resin and resin emulsified particles]
The molecular weight distribution is measured by gel permeation chromatography and the weight average molecular weight Mw is calculated by the following method. The weight average molecular weight of the resin emulsified particles was measured after the resin emulsified particles were dried by lyophilization.
(1) Preparation of sample solution A binder resin or resin emulsion is dissolved in chloroform 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 [manufactured by Sumitomo Electric Industries, Ltd., “FP-200”] to remove insoluble components to obtain a sample solution.
(2) Molecular weight distribution measurement Using the following apparatus, chloroform is flowed 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. In this calibration curve, several types of monodisperse polystyrene (2.63 × 10 ³ , 2.06 × 10 ⁷ , 1.02 × 10 ⁵ , manufactured by Tosoh Corporation), 2.10 × manufactured by GL Sciences Inc. 10 ³ , 7.00 × 10 ³ , 5.04 × 10 ⁴ ) are used as standard samples.
Measuring device: CO-8010, CCPE, AS-800 (manufactured by Tosoh Corporation)
Analysis column: GMHLX + G3000HXL (manufactured by Tosoh Corporation)

[Particle size and particle size distribution of emulsified particles and coalesced particles]
(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. The CV value was calculated according to the following formula.
CV value = (standard deviation of particle size distribution / volume median particle size (D ₅₀ )) × 100

[Toner particle size]
Measuring machine: Coulter Multisizer II (Beckman Coulter, Inc.)
Aperture diameter: 50 μm
Analysis software: Coulter Multisizer AccuComp version 1.19 (Beckman Coulter)
Electrolyte: Isoton II (Beckman Coulter, Inc.)
Dispersion: Emulgen 109P (manufactured by Kao Corporation, polyoxyethylene lauryl ether, HLB: 13.6) is dissolved in the electrolyte so as to have a concentration of 5% by weight to obtain a dispersion.
Dispersion conditions: 10 mg of a measurement sample is added to 5 ml of the dispersion, and dispersed for 1 minute with an ultrasonic disperser, then 25 ml of an electrolyte is added, and further dispersed for 1 minute with an ultrasonic disperser. Prepare a dispersion.
Measurement conditions: By adding the sample dispersion to 100 ml of the electrolytic solution, the particle size of 30,000 particles is adjusted to a concentration that can be measured in 20 seconds, and then 30,000 particles are measured. Determine the volume median particle size (D ₅₀ ). The CV value was calculated according to the following formula.
CV value = (standard deviation of particle size distribution / volume median particle size (D ₅₀ )) × 100

Production Example 1 (Production of polyester A)
32 g of polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, 2896 g of polyoxyethylene (2.0) -2,2-bis (4-hydroxyphenyl) propane, 1524 g of terephthalic acid, 83 g of glycerin and 20 g of tin octylate (esterification catalyst) are placed in a four-necked flask equipped with a nitrogen introduction tube, a dehydration tube, a stirrer, and a thermocouple, and at 235 ° C. under a nitrogen atmosphere and normal pressure (101.3 kPa). For 3.5 hours to obtain polyester A.

Production Example 2 (Production of polyester B)
The same as in Production Example 1 except that 2437 g of polyoxyethylene (2.0) -2,2-bis (4-hydroxyphenyl) propane, 1552 g of terephthalic acid, 138 g of glycerin and 21 g of tin octylate (esterification catalyst) were used. Thus, polyester B was obtained.

Production Example 3 (Production of polyester C)
578 g of polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, 2145 g of polyoxyethylene (2.0) -2,2-bis (4-hydroxyphenyl) propane, 1826 g of terephthalic acid, Polyester C was obtained in the same manner as in Production Example 1 except that 253 g of glycerin and 20 g of tin octylate (esterification catalyst) were used.

Production Example 4 (Production of polyester D)
473 g of polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, 1755 g of polyoxyethylene (2.0) -2,2-bis (4-hydroxyphenyl) propane, 1419 g of terephthalic acid, Polyester D was obtained in the same manner as in Production Example 1 except that 164 g of sorbitol and 19 g of tin octylate (esterification catalyst) were used and the reaction time was 5.5 hours.

Production Example 5 (Production of polyester E)
8320 g of polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, 80 g of polyoxyethylene (2.0) -2,2-bis (4-hydroxyphenyl) propane, 1592 g of terephthalic acid and 32 g of dibutyltin oxide (esterification catalyst) was reacted at 230 ° C. under normal pressure for 5 hours under a nitrogen atmosphere, and further reacted under reduced pressure (8 kPa). 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 E.

Production Example 6 (Production of polyester F)
17500 g of polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, 16250 g of polyoxyethylene (2.0) -2,2-bis (4-hydroxyphenyl) 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 inlet tube, a dehydrating tube, a stirrer and a thermocouple, and stirred at 220 ° C. in a nitrogen atmosphere. Polyester F was obtained by reacting until the softening point measured in accordance with ASTM D36-86 reached 120 ° C.

Production Example 7 (Production of polyester G)
2205 g of polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, 878 g of polyoxyethylene (2.0) -2,2-bis (4-hydroxyphenyl) propane, 762 g of terephthalic acid, 941 g of dodecenyl succinic anhydride and 25 g of dibutyltin oxide (esterification catalyst) are placed in a four-necked flask equipped with a nitrogen introduction tube, a dehydration tube, a stirrer, and a thermocouple, and at 235 ° C. under atmospheric pressure for 6 hours. After making it react, it was made to react under reduced pressure for 3 hours. Thereafter, 173 g of trimellitic anhydride was added and reacted at 215 ° C. under normal pressure for 1 hour, followed by reaction under reduced pressure until the softening point measured according to ASTM D36-86 reached 112 ° C. Polyester G was obtained.

  For each of the polyesters A to G obtained above, each property, that is, a sieve when 1 kg of resin is sieved with a JIS Z 8801 sieve having a weight average molecular weight, a softening point, a glass transition point, an acid value, and an opening diameter of 5.6 mm. The above remaining states are summarized in Table 1 below.

Example 1
In a 5 liter stainless steel kettle, polyester A 600 g, copper phthalocyanine pigment (ECB-301: manufactured by Dainichi Seika Kogyo Co., Ltd.), nonionic surfactant [“Emulgen 430 (manufactured by Kao)”, polyoxy 6 g of ethylene oleyl ether (HLB: 16.2)], 20 g of an anionic surfactant [“Neoperex G-15 (manufactured by Kao)”, sodium dodecylbenzenesulfonate (concentration: 15% by weight)], and medium 252 g of a potassium hydroxide aqueous solution (concentration: 5% by weight) was added as a compatibilizer, and the mixture was dispersed with a chi-type stirrer at 95 ° C. and normal pressure (101.3 kPa) with stirring at 250 r / min. The contents were stirred for 2 hours after reaching 95 ° C., and then 1118 g of deionized water was added dropwise at a rate of 6 g / min with stirring at 200 r / min with a chi-type stirrer to form a 200 mesh (mesh opening: 105 μm) wire mesh. Through the process, a finely divided resin emulsion 1 was obtained.

Examples 2 to 4 and Comparative Examples 1 and 2
Except having replaced polyester A with polyester shown in Table 2, it carried out similarly to Example 1, and performed Examples 2-4 and Comparative Examples 1 and 2, and obtained resin emulsions 2-6. In Comparative Example 1, deionized water was added dropwise, but phase inversion did not occur and emulsification could not be performed.

Reference production example 1
In a 5 liter stainless steel kettle, 105 g of polyester F, 195 g of polyester E, and nonionic surfactant “Emulgen 430 (manufactured by Kao)” (polyoxyethylene lauryl ether (EO = 30 mol addition)), cloud point: 100 ° C. As described above, 3 g of HLB: 16.2), 40 g of anionic surfactant “Neopelex G-15 (manufactured by Kao Corporation)” (sodium dodecylbenzenesulfonate (solid content 15 wt%, moisture 85 wt%)), copper phthalocyanine 15 g of pigment (ECB-301, manufactured by Dainichi Seika Kogyo Co., Ltd.), 138 g of potassium hydroxide aqueous solution (concentration: 5% by weight) as a neutralizing agent (amount necessary to neutralize 100% of polyester A) are The mixture was dispersed at 95 ° C. with stirring at 200 r / min. The contents are stirred for 2 hours after reaching 95 ° C. Thereafter, 568 g of deionized water was added dropwise at 3 g / min with stirring at 200 r / min with a Kai-type stirrer, and a resin emulsion 7 was obtained through a 200 mesh (mesh size: 105 μm) wire mesh. No resin component remained on the wire mesh. The particle size of the resin emulsion 7 was 0.15 μm and CV26.

Polyesters used and properties of each of the obtained resin emulsions (volume median particle size D ₅₀ of resin emulsion particles, CV value, weight average molecular weight of resin and resin emulsion particles, solid content concentration, remaining state on wire mesh) Is shown in Table 2.
Each of the resin emulsions was evaluated for hydrolyzability as follows. The results are shown in Table 2.

[Hydrolysis resistance]
The weight average molecular weights of the resin and resin emulsified particles were measured, and the hydrolyzability by alkali at the time of preparing the resin emulsion was confirmed. That is, the weight average molecular weights Mw ₁ and Mw ₂ of the used resin and resin emulsified particles were measured by the above-described methods, respectively, and the change rate of the weight average molecule was calculated as the hydrolysis change rate from the following formula. Since the solid content in the resin emulsified particles is composed of 90% by weight or more of the binder resin, the weight average molecular weight Mw ₂ of the resin emulsified particles is substantially regarded as the weight average molecular weight of the binder resin in the resin emulsified particles. sell. The results are shown in Table 2 according to the following criteria.
Hydrolysis change rate (%) = (weight average molecular weight Mw _{2 of} resin emulsified particles / weight average molecular weight Mw _{1 of} resin used) × 100

Evaluation criteria A: Almost no hydrolysis is observed when the hydrolysis change rate is 90% or more. B: Although some hydrolysis is observed when the hydrolysis change rate is 80% or more and less than 90%, there is no practical problem.
C: Hydrolysis is observed when the rate of hydrolysis change is 70% or more and less than 80%.
D: Hydrolysis change rate is less than 70% Hydrolysis is remarkable, and there is a problem in practical use.

Example 5
400 g of resin emulsion 1 was mixed in a 2 liter container at room temperature. Next, under stirring at 100 r / min with a Kai-type stirrer, 6.30 g of ammonium sulfate (molecular weight: 132.14) as a flocculant was dissolved in 104 g of deionized water and dissolved in an aqueous solution (pH: 6.1, 0). .25 mmol / L) 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 1.5 hours, and then heating was stopped.
After cooling to room temperature, colored resin fine particles (toner mother particles) were obtained through a suction filtration step, a washing step and a drying step. The volume median particle size (D ₅₀ ) of the toner base particles was 4.5 μm.
To 100 parts by weight of the toner base particles, 1.0 part by weight of hydrophobic silica (manufactured by Wacker Chemie, “TS530”, primary number average particle diameter: 8 nm) is externally added using a Henschel mixer, and cyan toner is added. It was. With the obtained cyan toner, a good image was obtained with a commercially available full-color printer. The obtained toner had a softening point of 102.5 ° C. and a glass transition point of 57.1 ° C.

Examples 6 to 8 and Comparative Example 3
Except that the resin emulsion 1 was changed as shown in Table 3, Examples 6 to 8 and Comparative Example 3 were performed in the same manner as in Example 5 to obtain toner.
Table 3 shows the properties of the toner thus obtained (volume median particle size (D ₅₀ ) of toner base particles, softening point of toner, glass transition point).

Example 9
200 g of resin emulsion 7 and 52 g of deionized water were placed in a 2 liter container, and then 253 g of an aqueous 0.45 mol / L ammonium sulfate solution was added dropwise over 30 minutes at room temperature while stirring at 100 r / min with a chi-type stirrer. did. Thereafter, while stirring, the temperature was increased at a temperature increase rate of 0.16 ° C./min to form aggregated particles. When the temperature reached 57 ° C., the temperature was fixed at 57 ° C. and held for 3 hours. Thereby, aggregated particles were obtained.
While maintaining the obtained agglomerated particles at 57 ° C., a liquid mixture of 208 g of resin emulsion 1 and 54 g of deionized water was added dropwise at a rate of 1 g / min. 30 minutes after the completion of dropping, a dilute solution obtained by diluting 4.2 g of a polyoxyethylene dodecyl ether sodium sulfate aqueous solution (solid content 28 wt%) with 37 g of deionized water was added.
30 minutes after the addition of the diluent, the temperature was raised to 80 ° C. at 0.16 ° C./min. After the temperature reached 80 ° C. and maintained at 80 ° C. for 1 hour, heating was terminated.
The mixture was gradually cooled to room temperature, and toner mother particles were obtained through a suction filtration step, a washing step, and a drying step.
To 100 parts by weight of the toner base particles, 1.0 part by weight of hydrophobic silica (manufactured by Wacker Chemie, “TS530”, primary number average particle diameter: 8 nm) is externally added using a Henschel mixer, and cyan toner is added. It was. The obtained toner had a volume-median particle size D ₅₀ of 5.0 μm.

For each of the obtained toners, the toner storage stability was evaluated as follows. The results are shown in Table 3.
[Toner storage stability test]
10 g of toner was put into a 20 ml unsealed polybin and left in an environment at a temperature of 50 ° C. for 48 hours. After standing, the degree of aggregation was measured with a powder tester (manufactured by Hosokawa Micron), and the toner storage stability was evaluated according to the following criteria. The results are shown in Table 3. In addition, the aggregation degree using a powder tester was specifically determined as follows.
Set three different mesh sieves in the order of 250μm on the upper stage, 149μm on the middle stage, and 74μm on the lower stage on the powder tester's shaking table, place 2g of toner on it and vibrate, and measure the weight of toner remaining on each sieve To do.

The measured toner weight is applied to the following equation and calculated to obtain the degree of aggregation [%].
Aggregation degree [%] = a + b + c
a = (weight of residual toner on upper stage) / 2 [g] × 100
b = (middle stage residual toner weight) / 2 [g] × 100 × (3/5)
c = (lower stage residual toner weight) / 2 [g] × 100 × (1/5)
Evaluation criteria A: The degree of aggregation was less than 10 and the storage stability was very good.
B: The degree of aggregation was 10 or more and less than 20, and the storage stability was good.
C: The degree of aggregation was 20 or more and the storage stability was poor.

  The resin emulsion of the present invention can be suitably used for a high-quality electrophotographic toner used in a one-component developer or a two-component developer mixed with a carrier.

Claims (4)

(A) A step of neutralizing a binder resin having an acid group with a basic compound containing a polyester obtained from a raw material monomer containing 1 to 15 mol% of glycerin in an aqueous medium to obtain a resin emulsion, And (b) a step of aggregating and coalescing the resin emulsified particles in the obtained resin emulsion, and a method for producing an electrophotographic toner. An acid value of 6~30mgKOH / g of the binder resin having an acid group, according to claim 1 for electrophotography method for producing a toner according. In step (I), neutralization is performed at a temperature not lower than the glass transition point of the binder resin and not higher than the softening point, and then the neutralized resin emulsion is not lower than the glass transition point of the binder resin and not higher than the softening point. adding an aqueous medium at a temperature, according to claim 1 or 2 method for producing a toner for electrophotography according to. An electrophotographic toner obtained by aggregating and coalescing resin emulsion particles in a resin emulsion obtained by neutralizing a binder resin having an acid group with a basic compound in an aqueous medium, A toner for electrophotography , wherein the binder resin having a group contains a polyester obtained from a raw material monomer containing 1 to 15 mol% of glycerin .