WO2011074580A1

WO2011074580A1 - Method for producing toner

Info

Publication number: WO2011074580A1
Application number: PCT/JP2010/072491
Authority: WO
Inventors: 浩司水畑
Original assignee: 花王株式会社
Priority date: 2009-12-14
Filing date: 2010-12-14
Publication date: 2011-06-23
Also published as: JP5552493B2; DE112010004799T5; JPWO2011074580A1; CN102652287B; CN102652287A

Abstract

Disclosed are: a toner for electrophotography, which has excellent storage stability and excellent fixability including fixability at low temperatures and hot offset resistance; and a method for producing the toner for electrophotography. Specifically disclosed is a method for producing a toner, which comprises: (1) a step in which release agent particles are obtained by emulsifying (A) a release agent and (B) a release agent having a melting point higher than that of the release agent (A) by 5°C or more in an aqueous medium in the presence of a polycarboxylic acid salt; and (2) a step in which the thus-obtained release agent particles and resin particles are agglomerated and coalesced together.

Description

Toner production method

The present invention relates to a toner manufacturing method and an electrophotographic toner obtained by the manufacturing method.

In the field of electrophotographic toner, with development of an electrophotographic system, development of a toner corresponding to high image quality and high speed is required. From the viewpoint of high image quality, it is necessary to reduce the particle size of the toner, and so-called chemical toners obtained by a chemical method such as a polymerization method or an emulsification dispersion method instead of the conventional melt-kneading method are disclosed. Furthermore, from the viewpoint of speeding up, a chemical toner containing a release agent has been reported to improve low-temperature fixability in fixability. However, unlike the melt kneading and pulverizing method, the chemical method does not have a kneading step. The dispersibility of the mold in the toner was not sufficient.
Patent Document 1 discloses a release agent dispersion having improved this point, that is, a release agent dispersion for toner containing a release agent and a dibasic acid having an alkyl group and / or an alkenyl group or a salt thereof. Has been. On the other hand, Patent Documents 2 and 3 disclose a technique in which two or more types of release agents are melt-mixed and used as a dispersion from the viewpoint of further improving hot offset resistance in fixability.

JP 2008-33139 A JP 2006-267280 A JP 2007-218961 A

However, when a chemical toner is obtained by agglomerating and coalescing resin particles and release agent particles, when two or more types of release agent particles are used in order to obtain a wide fixable temperature range, these are agglomerated together with the resin particles. In this case, the release agent particles have different stability, so that they cannot be aggregated with the resin particles, or the particle size distribution is very broad.
On the other hand, depending on the type of release agent, the affinity with resin particles is low, and even if aggregation is possible, there is a problem that the release agent particles are released from the aggregated particles during the coalescence process after the aggregation process. There are things to do.
That is, the present invention provides a small particle diameter at the time of toner production even when two or more types of release agents are used in the production of a chemical toner obtained by agglomerating and coalescing resin particles and release agent particles. It is an object of the present invention to provide a toner manufacturing method that can control the aggregation of the toner and does not release the release agent during the coalescence process.
Another object of the present invention is to provide an electrophotographic toner excellent in fixability and storage stability including low-temperature fixability and hot offset resistance.

The present invention
[1] (1) A release agent (A) and a release agent (B) having a melting point higher by 5 ° C. than the melting point of the release agent (A) in an aqueous medium in the presence of a polycarboxylic acid salt And (2) a toner production method comprising a step of agglomerating and coalescing the obtained release agent particles and resin particles, and [2] described in [1] above. An electrophotographic toner obtained by the production method of
About.

The present invention provides an agglomerated control with a small particle size at the time of toner production, that is, an agglomerated particle having a sharp particle size distribution, and a toner production method that does not release a release agent during the coalescence process. can do.
Further, according to the present invention, it is possible to provide an electrophotographic toner excellent in low-temperature fixability and hot offset resistance, that is, fixability and storage stability.

[Toner Production Method]
The toner production method of the present invention comprises (1) a release agent (A) and a release agent (B) having a melting point higher by 5 ° C. than the melting point of the release agent (A) in an aqueous medium. Emulsifying in the presence of a carboxylate to obtain release agent particles, and (2) a step of aggregating and coalescing the obtained release agent particles and resin particles.

That is, in a conventional chemical toner obtained by agglomerating and coalescing resin particles and release agent particles, when two or more types of release agent particles are used, the release agent particles are prepared and aggregated with the resin particles. Furthermore, since the stability of the respective release agent particles is different, it is difficult to properly aggregate the two or more types of release agent particles and the resin particles, that is, to generate aggregate particles having a sharp particle size distribution. In that case, release of the release agent was likely to occur at the time of aggregation or at the same time. That is, depending on the type of the release agent, even if aggregation is possible, the release agent particles are easily released from the aggregated particles during the coalescence process because of low affinity with the resin particles. The present invention solves the above-mentioned problems by providing a toner manufacturing method using release agent particles obtained by emulsifying at least the two specific types of release agents in the presence of a polycarboxylate. Can do.

(Process (1))
In step (1) in the method for producing a toner of the present invention, the release agent (A) and the release agent (B) having a melting point higher by 5 ° C. than the melting point of the release agent (A) are contained in an aqueous medium. In this step, the release agent particles are obtained by emulsification in the presence of a polycarboxylate.

Release agent (A) and release agent (B)
In the present invention, the release agent particles are usually obtained as a dispersion of release agent particles containing the release agent particles, that is, as a release agent dispersion, and the release agent (A) and release agent (B) used are as follows. From the viewpoint of low-temperature fixability of the toner, those having a melting point of 100 ° C. or less are preferably used, more preferably those having a melting point of 60 to 95 ° C., and still more preferably those having a melting point of 65 to 90 ° C. In particular, in the present invention, from the above viewpoint, the release agent (B) has a melting point of 100 ° C. or less, preferably 60 to 95 ° C., more preferably 65 to 90 ° C. Preferably, the melting point is 75 to 90 ° C., and more preferably the melting point is 80 to 85 ° C. In addition, the release agent (A) has a melting point of 100 ° C. or less, preferably 60 to 95 ° C., more preferably 65 to 90 ° C., and still more preferably 65 to 85 ° C. More preferably, the melting point is 70 to 80 ° C.

Specific examples of the release agent (A) and the release agent (B) include low molecular weight polyolefins such as polyethylene, polypropylene and polybutene; silicones having a softening point by heating; oleic acid amide, erucic acid amide, Fatty acid amides such as 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; montan wax, ozokerite, ceresin, paraffin Examples thereof include minerals such as wax, microcrystalline wax, and Fischer-Tropsch wax, and synthetic waxes such as petroleum wax and ester wax. As the release agent (A), mineral / petroleum wax and synthetic wax are preferable, and paraffin wax and ester wax are more preferable from the viewpoint of low-temperature fixability of the toner, and viewpoint of improving the storage stability of the toner. Therefore, paraffin wax is more preferable. As the mold release agent (B), a plant wax is preferable, and carnauba wax is more preferable.

In the present invention, for example, among these release agents, a release agent (A) and a release agent (B) having a melting point different by 5 ° C. or more may be selected and used. (A) and the release agent (B) may be of the same type or different types. In the present invention, the fixability of the obtained toner is improved by using at least two release agents having different melting points.

The release agent (B) is a release agent having a melting point higher by 5 ° C. or more than the melting point of the release agent (A). In view of excellent fixability of the obtained toner, it is preferable that the melting point is a release agent that is 6 ° C. or more higher than the release agent (A), and 8 ° C. or more higher than the release agent (A). More preferably, it is a mold release agent. The upper limit of the difference between the melting points of the release agent (A) and the release agent (B) is not particularly limited, but the upper limit is preferably 30 ° C. from the viewpoint of low-temperature fixability of the toner. 20 ° C. is more preferable. That is, from the viewpoint of toner fixability, the difference in melting point between the release agent (A) and the release agent (B) is preferably 6 to 30 ° C., more preferably 7 to 20 ° C., and more preferably 8 to 20 ° C. 8 to 9 ° C is more preferable.
By using a releasing agent having such a melting point, it is considered that even in fixing by low-temperature fixing, the releasing agent oozes out from the toner and the releasing effect is promoted to enable low-temperature fixing.
In the present invention, the melting point of the release agent can be measured using a differential scanning calorimeter, and specifically can be measured by the method described later.

In the present invention, from the viewpoint of fixability of the obtained toner, each of the release agent (A) and the release agent (B) is any one selected from carnauba wax, paraffin wax, polyolefin, and Fischer-Tropsch. More preferably, any of them is carnauba wax, more preferably, the release agent (B) is carnauba wax, and the release agent (A) is paraffin wax, polyolefin and One selected from Fischer-Tropsch.
From the viewpoint of toner fixing properties, the release agent particles in the release agent dispersion have a weight ratio of release agent (A) and release agent (B) (release agent (A) / release agent ( B)), preferably 5/95 to 95/5, more preferably 10/90 to 90/10, even more preferably 15/85 to 85/15, and 40/60 to 50 It is more preferable to contain / 50.
The release agent particles exhibit the effects of the present invention by containing the two types of release agents having different melting points, but may contain other release agents as long as the effects of the present invention are not impaired. .
From the viewpoint of obtaining an electrophotographic toner excellent in fixing property and storage stability, the total amount of the release agent (A) and the release agent (B) in the present invention in all the release agents is preferably 90% by weight or more. 99% by weight or more is more preferable, and 100% by weight is more preferable.

Polycarboxylate The release agent dispersion containing the release agent particles is characterized by containing a polycarboxylate together with the release agent (A) and the release agent (B). By using the polycarboxylate, moderate aggregation and coalescence of the resin particles and the release agent particles can be achieved by the interaction between the release agent (A), the release agent (B) and the polycarboxylate. It is considered possible.
Preferable specific examples of the polycarboxylate used in the present invention include polyacrylate, salt of acrylic acid-maleic acid copolymer, polymaleate and the like from the viewpoint of cohesiveness and prevention of release during toner production. Preferred is a salt of an acrylic acid-maleic acid copolymer. As the salt, an alkali metal salt is preferable, and a sodium salt is preferable. Specific examples include sodium polyacrylate represented by the following formulas (I) to (III), sodium salt of acrylic acid-maleic acid copolymer, sodium polymaleate and the like. More preferably, it is a sodium salt of an acid-maleic acid copolymer.

The degree of neutralization of the polymer end groups of the polycarboxylate is preferably from 50 to 100%, more preferably from 70 to 100%, still more preferably from 90 to 100%, from the viewpoint of the effect as a dispersant. Here, the degree of neutralization means a value measured by potentiometric titration of a polycarboxylate aqueous solution.

The weight average molecular weight of the polycarboxylate is preferably 3,000 to 90,000, more preferably 10,000 to 50,000, from the viewpoint of obtaining fine release agent particles. . This weight average molecular weight can be measured by gel permeation chromatography (GPC).
The cation forming the polycarboxylate is not particularly limited, but ammonium ions and alkylammonium ions can be used in addition to alkali metal ions such as sodium and potassium, and alkaline earth metal ions such as magnesium and calcium. . Among these, from the viewpoint of dispersibility of the release agent, alkali metal ions are preferable, and sodium ions are more preferable.

In the release agent dispersion, a polycarboxylic acid salt is preferably added in an amount of 0.1 to 5 weights from the viewpoints of aggregation control during the aggregation process at the time of toner preparation and dispersibility of the release agent in the obtained toner. %, More preferably 0.5 to 2.5% by weight. Further, from the same viewpoint, the release agent dispersion preferably contains 0.2 to 15 parts by weight of polycarboxylate salt, more preferably 0 to 100 parts by weight of the total release agent. 4 to 10 parts by weight, more preferably 0.6 to 6 parts by weight.

Release agent particles The release agent particles are usually obtained as a dispersion of release agent particles containing the release agent particles, that is, as a release agent dispersion.
The solid content concentration of the release agent in the release agent dispersion is preferably 5 to 40% by weight, more preferably 10 to 35% by weight, and more preferably 15 to 35% by weight from the viewpoints of emulsification and storage stability of the dispersion. Is more preferable. Further, from the viewpoint of the storage stability of the release agent dispersion, the pH of the release agent dispersion is preferably 5 to 10, more preferably 6 to 9.5.

Further, in the release agent dispersion, the release agent (A) and the release agent (B) are used from the viewpoint of aggregation control during the aggregation process at the time of toner preparation and the dispersibility of the release agent in the obtained toner. ) In a total amount of 5 to 40% by weight, more preferably 10 to 35% by weight, still more preferably 15 to 30% by weight.
The content ratio of the release agent (A) and the release agent (B) constituting the release agent particles in the release agent dispersion is the same as described above.
In the mold release agent dispersion, together with the mold release agent (A), mold release agent (B), and polycarboxylate, a conventionally known emulsifier can be used within a range not inhibiting the effects of the present invention. Examples of such an emulsifier include monobasic acid salts such as sodium stearate, potassium oleate, sodium dodecylbenzenesulfonate, and polymer dispersants such as polyvinyl alcohol.

From the viewpoint of toner fixing properties and durability, the volume median particle size (D50) of the release agent particles is preferably 1 μm or less, more preferably 0.05 to 1 μm, and more preferably 0.1 to 0.85 μm. Further preferred. In the present specification, the volume-median particle size (D50) 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 release agent dispersion has excellent emulsification performance by having the above-described configuration. The release agent particles in the release agent dispersion liquid preferably have a narrow particle size distribution from the viewpoints of toner fixing properties, durability, and aggregation properties. Specifically, the CV value (particle size distribution The standard deviation / volume median particle size (50) × 100) is preferably 50% or less, more preferably 45% or less, and still more preferably 40% or less. Here, the particle size and particle size distribution of the release agent particles can be specifically measured by a method described later using a light scattering particle size distribution measuring machine.
The release agent dispersion thus obtained has good emulsification performance and emulsification stability and is stable for a long time. Further, since the aggregation control during the aggregation process at the time of toner preparation is improved, the toner particle shape can be controlled, and the toner can be suitably used for an electrophotographic toner. Further, as will be described later, the release agent particles are used in a toner obtained by agglomerating and coalescing resin particles and release agent particles, and thereby achieve the effects of the present invention.

In the aqueous medium, the release agent particles include a release agent (A) and a release agent (B) having a melting point higher by 5 ° C. than the melting point of the release agent (A). It is obtained by a method of emulsifying in the presence.
Specifically, the release agent (A) and the release agent (B) are dispersed in an aqueous medium in the presence of a polycarboxylic acid salt, and preferably have a melting point higher than that of the release agent (B). While being heated, for example, it can be dispersed in the form of fine particles by a homogenizer having a strong shearing force, a pressure discharge type homogenizer, an ultrasonic disperser, or the like to obtain a dispersion of release agent particles.

The aqueous medium is mainly composed of water. From the environmental viewpoint, the content of water in the aqueous medium is preferably 80% by weight or more, more preferably 90% by weight or more, and further preferably 100% by weight.
Examples of components other than water in the aqueous medium include alcohol-based organic solvents such as methanol, ethanol, isopropanol, and butanol, and organic solvents that dissolve in water such as acetone, methyl ethyl ketone, and tetrahydrofuran. Among these, from the viewpoint of preventing mixing into the toner, alcohol-based organic solvents such as methanol, ethanol, isopropanol, and butanol, which are organic solvents that do not dissolve the resin, can be used. In the present invention, it is preferable to atomize the resin using only water without substantially using an organic solvent.
The dispersion temperature is preferably 60 to 120 ° C., more preferably 80 to 110 ° C., and still more preferably 80 to 100 ° C. from the viewpoint of emulsifiability of the release agent.

(Process (2))
Step (2) is a step of aggregating and coalescing the obtained release agent particles and resin particles. That is, the electrophotographic toner of the present invention is obtained by agglomerating and coalescing the aforementioned release agent particles and resin particles.
Resin Particles The resin particles in the present invention are obtained as a resin particle dispersion in which the resin particles are dispersed in an aqueous medium. The resin particles in the present invention preferably contain polyester from the viewpoint of low-temperature fixability and durability of the toner. From the same viewpoint, the polyester content is preferably 50% by weight or more, more preferably 60% by weight or more, more preferably 70% by weight or more, still more preferably 80% by weight or more, and substantially 100% by weight. Even more preferably. As the resin constituting the resin particles, in addition to polyester, known resins used for toners such as polyester, styrene acrylic copolymer, epoxy, polycarbonate, polyurethane and the like can be used.

When using polyester, although the raw material monomer is not specifically limited, Well-known alcohol components and well-known carboxylic acid components, such as carboxylic acid, carboxylic acid anhydride, and carboxylic acid ester, are used.
Examples of carboxylic acids include 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 2 to 2 carbon atoms. Divalent carboxylic acids such as succinic acid substituted with 20 alkenyl groups, trivalent or higher polyvalent carboxylic acids such as trimellitic acid and pyromellitic acid, anhydrides of these acids, and alkyls of these acids (carbon ## STR1 ## Examples include esters.
This carboxylic acid component may be used individually by 1 type, and may be used in combination of 2 or more type.

Examples of the alcohol component include bisphenol A such as polyoxypropylene-2,2-bis (4-hydroxyphenyl) propane and polyoxyethylene-2,2-bis (4-hydroxyphenyl) propane. Alkylene (2 to 3 carbon atoms) oxide (average added mole number 1 to 16) adduct, hydrogenated bisphenol A, ethylene glycol, propylene glycol, neopentyl glycol, 1,4-butanediol, 1,3-butanediol, Examples include 1,6-hexanediol, glycerin, pentaerythritol, trimethylolpropane, sorbitol, or an alkylene (2 to 4 carbon) oxide (average added mole number 1 to 16) adduct thereof. You may use the said alcohol in combination of 2 or more type.

The polyester can be produced, for example, by subjecting an alcohol component and a carboxylic acid component to condensation polymerization at a temperature of about 180 to 250 ° C. in an inert gas atmosphere, if necessary, using an esterification catalyst.
As the esterification catalyst, an esterification catalyst such as a tin compound such as dibutyltin oxide or tin dioctylate or a titanium compound such as titanium diisopropylate bistriethanolamate can be used. The amount of the esterification catalyst used is preferably 0.01 to 1 part by weight, more preferably 0.1 to 0.6 part by weight based on 100 parts by weight of the total amount of the alcohol component and the carboxylic acid component.

The polyester may be either a crystalline polyester or an amorphous polyester, but is preferably an amorphous polyester from the viewpoint of toner fixability and chargeability.
In the present invention, the “amorphous polyester” means that the crystallinity index defined by the ratio of the softening point to the endothermic maximum peak temperature (softening point / endothermic maximum peak temperature) is preferably larger than 1.3 and not larger than 4 More preferably, it is 1.5-3. From the viewpoint of toner fixing properties and storage stability, the softening point of the polyester is preferably 70 to 165 ° C, more preferably 90 to 165 ° C, and the glass transition point is preferably 50 to 85 ° C, and 55 to 85 ° C. It is more preferable that From the same viewpoint, the acid value is preferably 6 to 35 mgKOH / g, more preferably 10 to 35 mgKOH / g, and further preferably 15 to 35 mgKOH / g. The desired softening point and acid value can be obtained by adjusting the charging ratio of alcohol and carboxylic acid, the temperature of condensation polymerization, and the reaction time.

In the present invention, the polyester includes not only unmodified polyester but also polyester modified to such an extent that its properties are not substantially impaired. Examples of the modified polyester include grafting and blocking with phenol, urethane, epoxy and the like by the methods described in JP-A-11-133668, JP-A-10-239903, JP-A-8-20636, and the like. And a composite resin having two or more kinds of resin units including a polyester unit.

When the resin particles contain a plurality of resins, the softening point, glass transition point, and acid value of the resin constituting the resin particles are the softening point, glass transition point, acid value as a mixture of each resin. Each value is preferably the same value as that of the polyester.
Furthermore, when the polyester is contained, the resin constituting the resin particles can contain two kinds of polyesters having different softening points from the viewpoint of low-temperature fixability, hot offset resistance, and durability of the toner. The softening point of polyester (I) is preferably 70 ° C. or higher and lower than 115 ° C., and the softening point of the other polyester (II) is preferably 115 ° C. or higher and 165 ° C. or lower. The weight ratio (I / II) of polyester (I) to polyester (II) is preferably 10/90 to 90/10, more preferably 50/50 to 90/10.

In the present invention, the resin constituting the resin particles is preferably dispersed in an aqueous medium. The aqueous medium in which the resin is dispersed is mainly composed of water, and the same one as that used in the above-mentioned release agent dispersion can be used.
In the resin particle dispersion, additives such as a colorant and a charge control agent can be contained together with the resin as necessary.

The colorant is not particularly limited, and any known colorant can be used. Specifically, carbon black, inorganic complex oxide, chrome yellow, benzidine yellow, pyrazolone orange, vulcan orange, watch young red, brilliantamine 3B, brilliantamine 6B, lake red C, bengal, phthalocyanine blue, phthalocyanine green, etc. Various pigments and various dyes such as acridine series, azo series, benzoquinone series, azine series, anthraquinone series, indico series, phthalocyanine series, aniline black series, etc. are used alone or in combination of two or more. Can do.
The content of the colorant is preferably 20 parts by weight or less, more preferably 0.01 to 10 parts by weight with respect to 100 parts by weight of the resin.

Examples of the charge control agent include a metal salt of benzoic acid, a metal salt of salicylic acid, a metal salt of alkyl salicylic acid, a metal salt of catechol, a metal-containing bisazo dye, and a quaternary ammonium salt. 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 in the toner is preferably 10 parts by weight or less, and more preferably 0.01 to 5 parts by weight with respect to 100 parts by weight of the resin.

In the present invention, when the resin particles are produced as a dispersion, from the viewpoint of improving the dispersion stability of the resin, it is preferably 10 parts by weight or less, more preferably 5 parts by weight or less, with respect to 100 parts by weight of the resin. More preferably, 0.1 to 3 parts by weight, and still more preferably 0.5 to 2 parts by weight of a surfactant is present.
Examples of the surfactant include anionic surfactants such as sulfate ester, sulfonate, and soap; cationic surfactants such as amine salt type and quaternary ammonium salt type; polyethylene glycol type and alkylphenol ethylene Nonionic surfactants such as oxide adducts and polyhydric alcohols can be mentioned. Among these, ionic surfactants such as anionic surfactants and cationic surfactants are preferable. The nonionic surfactant is preferably used in combination with an anionic surfactant or a cationic surfactant. Although the said surfactant may be used individually by 1 type, you may use it in combination of 2 or more type.

Specific examples of the anionic surfactant include dodecyl benzene sulfonic acid, sodium dodecyl benzene sulfonate, sodium dodecyl sulfate, sodium alkyl ether sulfate, and the like. Among these, sodium dodecylbenzenesulfonate is preferable.
Specific examples of the cationic surfactant include alkylbenzene dimethyl ammonium chloride, alkyl trimethyl ammonium chloride, distearyl ammonium chloride and the like.

Nonionic surfactants include, for example, polyoxyethylene nonylphenyl ether, polyoxyethylene oleyl ether, polyoxyethylene alkyl aryl ethers such as polyoxyethylene lauryl ether, polyoxyethylene alkyl ethers, polyethylene glycol mono Examples thereof include polyoxyethylene fatty acid esters such as laurate, polyethylene glycol monostearate, and polyethylene glycol monooleate, and oxyethylene / oxypropylene block copolymers.

When preparing the resin particles as a dispersion, it is preferable to add an aqueous alkaline solution to the resin and disperse the resin and additives used as necessary.
The aqueous alkaline solution preferably has a concentration of 1 to 20% by weight, more preferably 1 to 10% by weight, and even more preferably 1.5 to 7.5% by weight. As the alkali to be used, it is preferable to use an alkali that enhances the surface activity when the resin becomes a salt. Specific examples thereof include monovalent alkali metal hydroxides such as potassium hydroxide and sodium hydroxide.
After the dispersion, preferably after neutralization at a temperature above the glass transition point of the resin, the resin particles can be produced by emulsification by adding an aqueous medium at a temperature above the glass transition point of the resin. .

The addition rate of the aqueous medium is preferably 0.1 to 50 g / min, more preferably 0.5 to 40 g / min, and further preferably 1 to 30 g / min per 100 g of resin from the viewpoint that emulsification can be effectively carried out. Minutes. 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 forming a dispersion of O / W type resin particles.
Examples of the aqueous medium used for producing the resin particles as a dispersion include the same aqueous medium used for dispersing the resin constituting the resin particles described above, preferably deionized water or distilled water. It is.
The amount of the aqueous medium is preferably from 100 to 2,000 parts by weight, more preferably from 150 to 1,500 parts by weight, based on 100 parts by weight of the resin, from the viewpoint of obtaining uniform aggregated particles in the subsequent aggregation treatment. From the viewpoint of the stability and handleability of the resulting resin particle dispersion, the solid content concentration of the resin particle dispersion is preferably 7 to 50% by weight, more preferably 7 to 40% by weight, and even more preferably 10%. The amount of aqueous medium is selected so that it is 35% by weight. The solid content includes non-volatile components such as resins, pigments, and nonionic surfactants.

Moreover, it is preferable that the temperature in the case of emulsification is the range more than the glass transition point of the resin which comprises a resin particle, and below a softening point from a viewpoint of preparing a fine resin particle. By carrying out at a temperature within the above range, emulsification is carried out smoothly and no special apparatus is required for heating. From this point, the temperature is equal to or higher than (the glass transition point of the resin constituting the resin particle + 10 ° C.) (meaning “temperature higher by 10 ° C. than the glass transition point”, hereinafter the same notation is similarly understood). It is also preferable that the temperature is not higher than (softening point of the resin −5 ° C.).
The volume median particle size (D50) of the resin particles thus obtained is preferably 0.02 to 2 μm, more preferably 0.05 to 1 μm in order to perform uniform aggregation in the subsequent aggregation process. More preferably, it is 0.05 to 0.6 μm.

Other methods for obtaining resin particles as a dispersion include, for example, a step of emulsifying and dispersing a polycondensable monomer as a target resin particle raw material in an aqueous medium by, for example, mechanical shearing or ultrasonic waves. A method is mentioned. At this time, if necessary, additives such as a polycondensation catalyst and a surfactant are also added to the water-soluble medium. And polycondensation is advanced by giving a heating etc. with respect to the obtained solution, for example. When the resin is polyester, the above-mentioned polyester polycondensable monomer and polycondensation catalyst can be used, and the above-mentioned surfactants can be used in the same manner.
Usually, polycondensation resins are accompanied by dehydration at the time of polymerization, and thus generally do not easily proceed in an aqueous medium. However, for example, when a polycondensable monomer is emulsified in an aqueous medium together with a surfactant that forms micelles in the aqueous medium, the monomer is placed in a micro hydrophobic field in the micelle. The dehydration reaction is facilitated, and the produced water can be discharged into an aqueous medium outside the micelles to allow the polymerization to proceed. In this way, a resin particle dispersion in which the resin particles of the polycondensation resin are dispersed in an aqueous medium with low energy is obtained.

Aggregation step In the toner production method of the present invention, the release agent particles and the resin particles obtained as described above are aggregated and united. Specifically, the release agent dispersion and the resin are combined. By mixing the particle dispersion, preferably adding an aggregating agent to obtain an aggregated particle dispersion, and then coalescing the aggregated particles in the obtained aggregated particle dispersion to obtain coalesced particles Can be manufactured.
The mixing ratio of the release agent particles and the resin particles when mixing the release agent dispersion and the resin particle dispersion, or the content ratio of the release agent and the resin particles in the obtained agglomerated particles depends on the low temperature fixability of the toner. From the viewpoint of ensuring storage stability, the weight ratio of the release agent to the resin (release agent / resin) is preferably 1/99 to 15/85, and preferably 2/98 to 12/88. Is more preferably 3/97 to 10/90.

Examples of the flocculant include organic salts and polyethyleneimine for organic flocculants, and inorganic metal salts, inorganic ammonium salts, metal complexes, and the like for inorganic flocculants. Examples of the organic salt include sodium acetate and ammonium acetate. Examples of the inorganic metal salt include sodium sulfate, sodium chloride, calcium chloride, magnesium chloride, zinc chloride, aluminum chloride, and aluminum sulfate. Examples thereof include inorganic metal salt polymers such as aluminum. Examples of the inorganic ammonium salt include ammonium sulfate, ammonium chloride, and ammonium nitrate.
In the present invention, from the viewpoint of achieving highly accurate toner particle size control and sharp particle size distribution, it is preferable to use a monovalent salt among the aggregating agents. Here, the monovalent salt means that the valence of the metal ion or cation constituting the salt is 1. As the monovalent salt, an inorganic flocculant such as the inorganic metal salt or ammonium salt is used. In the present invention, a water-soluble nitrogen-containing compound having a molecular weight of 350 or less is preferably used.

The water-soluble nitrogen-containing compound having a molecular weight of 350 or less is preferably an acidic compound from the viewpoint of rapidly agglomerating primary particles, and a 10% by weight aqueous solution having a pH value of 4 to 6 at 25 ° C. Of these, 4.2 to 6 are more preferable. Further, from the viewpoint of maintaining the chargeability of the toner at high temperature and high humidity, the molecular weight is preferably 350 or less, and more preferably 300 or less. Examples of such water-soluble nitrogen-containing compounds include ammonium salts such as ammonium halide, ammonium sulfate, ammonium acetate, and ammonium salicylate, and quaternary ammonium salts such as tetraalkylammonium halide. In view of the above, ammonium sulfate (pH value of a 10 wt% aqueous solution at 25 ° C., hereinafter simply referred to as pH value: 5.4), ammonium chloride (pH value: 4.6), tetraethylammonium bromide (pH value: 5. 6) and tetrabutylammonium bromide (pH value: 5.8) are preferred.

The amount of the flocculant used varies depending on the valency of the flocculant, but generally may be an amount that makes the concentration of the flocculant in the aggregated particle dispersion liquid 0.0001 to 10 mol / L. In general, from the viewpoint of toner charging properties, particularly charging characteristics in a high-temperature and high-humidity environment, 50 parts by weight or less is preferable, 40 parts by weight or less is more preferable, and 30 parts by weight or less is more preferable. Moreover, from a cohesive viewpoint, 1 weight part or more is preferable with respect to 100 weight part of resin, 3 weight part or more is more preferable, and 5 weight part or more is further more preferable. Considering the above points, the amount of the flocculant used is preferably 1 to 50 parts by weight, more preferably 3 to 40 parts by weight, and even more preferably 5 to 30 parts by weight with respect to 100 parts by weight of the resin.

At the time of agglomeration, from the viewpoint of controlling the agglomeration and the agglomerated particles to have a small particle size and a sharp particle size distribution, the temperature in the agglomerated system is (temperature of the glass transition point of the resin constituting the resin particles + 25) ° C. or less. From the viewpoint of suppressing coarse particles, more preferably, (glass transition point−30) ° C. to (glass transition point + 25 ° C.), more preferably 25 ° C. to (glass transition point + 15) ° C., even more Preferably, it is in the range of 35 ° C. to (glass transition point + 5) ° C.
When adding the flocculant, the flocculant can be added as an aqueous medium solution. The flocculant may be added at once, or may be added continuously or intermittently. Moreover, it can also be divided and added. It is preferable to sufficiently stir at the time of adding the flocculant and after completion of the addition.

The glass transition point of the aggregated particles in the aggregated particle dispersion is preferably 50 to 80 ° C., more preferably 52 to 75 ° C., and further preferably 55 to 70 ° C. from the viewpoint of storage stability of the toner. It is.
The aggregated particles contained in the aggregated particle dispersion have a volume median particle size (D50) of 1 to 10 μm, more preferably 2 to 9 μm, and still more preferably 2 to 2 μm, from the viewpoint of reducing the particle size of the obtained toner. It is preferably in the range of 5 μm. The variation coefficient (CV value) of the particle size distribution is preferably 30% or less, more preferably 28% or less, and further preferably 25% or less.
The solid content concentration in the dispersion of the aggregated particles is preferably 5 to 50% by weight, more preferably 5 to 40% by weight from the viewpoint of controlling the aggregation of the aggregated particle dispersion.

In the present invention, from the viewpoint of preventing the release of the release agent or the like from the toner particles, or in the color toner, the charge amount between the respective colors is set to the same level, the aggregated particle dispersion is added to the resin fine particle dispersion. It is preferable to manufacture the toner through a step of adding the resin at once or divided into a plurality of times to obtain resin fine particle-attached aggregated particles.
In the present invention, resin fine particles adhered to the aggregated particles with respect to the resin particles constituting the aggregated particles (hereinafter sometimes referred to as “resin particles in the present invention”) are hereinafter simply referred to as “resin fine particles”.

When the resin fine particles are added in a plurality of times, the amount of each resin fine particle is preferably the same amount, and when the resin fine particles are added in a divided manner, the amount of each resin fine particle is the same. An amount is preferred. In addition, when the resin fine particles are added in a plurality of times, the number of times is not particularly limited, but is preferably 2 to 10 times and more preferably 2 to 8 times from the viewpoint of the particle size distribution of the formed aggregated particles. preferable.
In the present invention, the resin fine particles added to the aggregated particles are not particularly limited, and for example, those prepared in the same manner as the resin particles in the present invention can be used.
In the present invention, the resin fine particles may be the same as or different from the resin particles in the present invention. From the viewpoint of low-temperature fixability and storage stability of the toner, the resin fine particles are preferably in the present invention. The resin particles are resin fine particles having different physical properties such as a glass transition point, a softening point, and a molecular weight.
The addition timing of the resin fine particles is not particularly limited as long as it can be adhered to the aggregated particles, but from the viewpoint of controlling the particle diameter of the resin fine particle-adhered aggregated particles, after the first addition of the coagulant, the process of producing the coalesced particles Is preferably between.

The mixing ratio of the aggregated particles to the resin fine particles (aggregated particles / resin fine particles) in the aggregated particle dispersion is preferably 0.1 to 3.0 by weight from the viewpoint of low-temperature fixability and storage stability of the toner. More preferably, it is 0.2 to 2.5, and still more preferably 0.3 to 2.0.
From the viewpoint of high image quality, the volume median particle size (D50) of the resin fine particle-attached aggregated particles is preferably 1 to 10 μm, more preferably 2 to 10 μm, and further preferably 3 to 9 μm.

In the present invention, it is preferable to add an aggregation terminator before coalescence from the viewpoint of preventing further unnecessary aggregation after aggregation or after the addition of resin fine particles. A surfactant is preferably used as the aggregation terminator, but an anionic surfactant is more preferably used. Of the anionic surfactants, it is more preferable to add at least one selected from the group consisting of alkyl ether sulfates, alkyl sulfates, and linear alkylbenzene sulfonates.
The aggregation terminator may be used singly or in combination of two or more.

The addition amount of the aggregation terminator is selected from the viewpoints of aggregation termination properties and persistence to the toner, the resin constituting the aggregated particles or the resin constituting the resin particle-attached aggregated particles (that is, the resin and resin fine particles constituting the aggregated particles) The total amount of the resin constituting the resin is preferably 0.1 to 15 parts by weight, more preferably 0.1 to 10 parts by weight, and still more preferably 0.1 to 8 parts by weight with respect to 100 parts by weight. The aggregation terminator may be added in any form as long as it is the above addition amount, but it is preferably added in an aqueous solution from the viewpoint of productivity. Each said salt may be added at once, and may be added intermittently or continuously.

Combined Step In the present invention, it is preferable that after the aggregated particles or resin fine particle-attached aggregated particles are produced, they are fused and combined to obtain combined particles.
The resin fine particle adhering aggregated particles, when coalesced, the resin particles and release agent particles in the aggregated particles, the resin particles and release agent particles in the resin fine particle adhering aggregate particles, the resin fine particles, and the resin fine particle adhering In the aggregated particles, the aggregated particles and the resin fine particles are mainly physically attached, and the aggregated particles are united together and the resin fine particles are combined with each other, and the aggregated particles and the resin fine particles are combined. It is presumed that the particles are fused together to form a unified particle.

It is preferable that the heating temperature at the time of combination is a temperature that is not less than the glass transition point of aggregated particles and not more than 100 ° C., more preferably a temperature that is not less than the glass transition point of aggregated particles and not more than 90 ° C., The temperature is preferably such that it is not less than the glass transition point of the aggregated particles and not more than 85 ° C. At temperatures lower than this, fusion may not proceed. If the temperature is higher than this, the release agent may be released from the aggregated particles.
In the case of the dispersion of resin fine particle-adhered aggregated particles, the heating temperature is not less than the glass transition point of the resin constituting the resin fine particles and the softening point of the resin +20 from the viewpoint of target shape control and fusing property of the toner. ° C) or less, more preferably (glass transition point of the resin + 5 ° C.) or more and (softening point of the resin + 15 ° C.) or less, more preferably (glass transition point of the resin + 10 ° C.) or more and ( The softening point of the resin + 10 ° C. or lower.

The obtained coalesced particles become toner particles through a solid-liquid separation process such as filtration, a washing process, and a drying process.
The drying step is a step of obtaining toner particles by drying the coalesced particles obtained in the coalescing step through a solid-liquid separation step such as filtration and a washing step as necessary. As a drying method, 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 adopted. The water content after drying of the toner particles is preferably adjusted to 1.5% by weight or less, more preferably 1.0% by weight or less, from the viewpoint of chargeability of the toner.

From the viewpoint of improving the image quality of the toner, the volume median particle size (D50) of the coalesced particles and toner particles is preferably 1 to 10 μm, more preferably 2 to 8 μm, and even more preferably 3 to 8 μm. Further, the CV value of the coalesced particles and toner particles described above is preferably 30% or less, and more preferably 25% or less. The particle size and particle size distribution of the toner (particles) can be measured by the method described below.

[Electrophotographic toner]
The electrophotographic toner of the present invention is obtained by the toner production method.
The softening point of the electrophotographic toner of the present invention is preferably from 60 to 140 ° C., more preferably from 65 to 130 ° C., still more preferably from 70 to 120 ° C., from the viewpoint of low-temperature fixability. The glass transition point is preferably from 30 to 80 ° C., more preferably from 40 to 70 ° C., from the viewpoint of toner durability. In addition, the measuring method of a softening point and a glass transition point is based on these measuring methods in resin.
The content of the release agent in the electrophotographic toner of the present invention is preferably 0.5 to 20 parts by weight from the viewpoint of toner fixability with respect to 100 parts by weight of the binder resin in the toner. The amount is preferably 1 to 18 parts by weight, more preferably 1.5 to 15 parts by weight. When the colorant and the charge control agent are contained, the content of the colorant is preferably 20 parts by weight or less, more preferably 0.01 to 10 parts by weight with respect to 100 parts by weight of the binder resin in the toner. The charge control agent is preferably 10 parts by weight or less, more preferably 0.01 to 5 parts by weight with respect to 100 parts by weight of the binder resin in the toner.

In the toner of the present invention, the obtained toner particles may be used as they are, or a toner obtained by adding an additive such as a fluidizing agent to the toner particle surface as an external additive may be used as the toner. it can. As the external additive, known fine particles such as inorganic fine particles such as silica fine particles, titanium oxide fine particles, and alumina fine particles whose surface is hydrophobized, and polymer fine particles such as polymethyl methacrylate and silicone resin can be used.
The amount of the external additive is preferably 1 to 5 parts by weight, more preferably 1.5 to 3.5 parts by weight, based on 100 parts by weight of the toner particles before processing with the external additive.
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.

In the following examples and the like, 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 a mixed solvent of acetone and toluene (acetone: toluene = 1: 1 (volume ratio)).

[Softening point and glass transition point of resin]
(1) Softening point Using a flow tester (manufactured by Shimadzu Corporation, “CFT-500D”), a 1 g sample was heated at a heating rate of 6 ° C./min, and a load of 1.96 MPa was applied by a plunger. Extrude from a nozzle of 1 mm length 1 mm. 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 Using a differential scanning calorimeter (Parkin Elmer, Pyris6 DSC), the temperature was raised to 200 ° C., and the sample was cooled to −10 ° C. at a temperature reduction rate of 10 ° C./min from that temperature. Measure at 10 ° 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.

[Melting point of release agent]
Using a differential scanning calorimeter (DSC210, manufactured by Seiko Denshi Kogyo Co., Ltd.), the temperature is measured from 20 ° C. at a heating rate of 10 ° C./min, and the maximum peak temperature is taken as the melting point.

[Molecular weight of polyacrylate]
GPC (gel permeation chromatography)
Measurement is carried out under the following conditions using a measuring apparatus: CO-8010 (manufactured by Tosoh Corporation). The molecular weight of the sample is calculated based on a calibration curve prepared in advance using polyethylene glycol as the standard substance.
Column: TSK PWXL + G4000PWXL + G2500PWXL (both manufactured by Tosoh Corporation)
Column temperature: 40 ° C
Eluent: 0.2 mol / L phosphate buffer / acetonitrile (9/1)
Flow rate: 1.0 mL / min
Injection volume: 0.1 mL

[Particle size of resin particles, resin particles and release agent particles]
(1) Measuring device: Laser scattering type particle size measuring machine (Horiba, LA-920)
(2) Measurement conditions: Distilled water is added to the measurement cell, and the volume-median particle size (D50) is measured at a temperature where the absorbance falls within an appropriate range. The particle size distribution is represented by a CV value (standard deviation of particle size distribution / volume median particle size (D50) × 100).

[Solid concentration of dispersion]
Using an infrared moisture meter (Kett Science Laboratory Co., Ltd .: FD-230), 5 g of the dispersion was dried at a drying temperature of 150 ° C. in a measurement mode 96 (monitoring time 2.5 minutes / variation width 0.05%). % Is measured. The solid content was calculated according to the following formula.
Solid content (%) = 100-M
M: Moisture (%) = [(W−W0) / W] × 100
W: Sample weight before measurement (initial sample weight)
W0: Sample weight after measurement (absolute dry weight)

[Agglomerated particles, aggregated particles of resin fine particles, and particle size of coalesced particles]
・ Measuring machine: Coulter Multisizer III (Beckman Coulter)
・ Aperture diameter: 50μm
-Analysis software: Multisizer III version 3.51 (manufactured by Beckman Coulter)
・ Electrolyte: Isoton II (Beckman Coulter)
Measurement conditions: After adjusting the particle size of 30,000 particles to a concentration that can be measured in 20 seconds by adding the aggregated particle dispersion, the resin particle adhesion aggregated particle dispersion, or the coalesced particle dispersion to 100 mL of the electrolytic solution. 30,000 particles are measured, and the volume median particle size (D50) is determined from the particle size distribution. The particle size distribution is represented by a CV value (standard deviation of particle size distribution / volume median particle size (D50) × 100). The fine powder amount is represented by the content ratio (number%) of components having a particle size of 2 μm or less in the number average particle size.

[Toner particle size]
-Measuring machine: Coulter Multisizer III (Beckman Coulter, Inc.)
・ Aperture diameter: 50μm
・ Analysis software: Multisizer III version 3.51 (Beckman Coulter, Inc.)
・ Electrolyte: Isoton II (Beckman Coulter)
-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 condition: 10 mg of a measurement sample is added to 5 mL of the dispersion, and dispersed for 1 minute with an ultrasonic disperser, and then 25 mL of an electrolyte is added, and further dispersed for 1 minute with an ultrasonic disperser. A sample dispersion is prepared.
Measurement conditions: The sample dispersion is added to 100 mL of the electrolytic solution to adjust the particle size of 30,000 particles to a concentration that can be measured in 20 seconds, and then 30,000 particles are measured and the particle size distribution thereof. To determine the volume-median particle size (D50).
The particle size distribution is indicated by a CV value (standard deviation of particle size distribution / volume median particle size (D50) × 100) (%).

Polyester production example 1 (Production of polyester A)
Polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane 8,320 g, Polyoxyethylene (2.0) -2,2-bis (4-hydroxyphenyl) propane 80 g, terephthalic acid 1,592 g and 32 g of dibutyltin oxide (esterification catalyst) were reacted at 230 ° C. under normal pressure (101.3 kPa) for 5 hours under a nitrogen atmosphere, and further reacted under reduced pressure (8.3 kPa). After cooling to 210 ° C., 1,672 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 A. Polyester A had a softening point of 110 ° C., a glass transition point of 66 ° C., and an acid value of 24.4 mgKOH / g.

Polyester production example 2 (Production of polyester B)
Polyoxypropylene (2.2) -2, 2-bis (4-hydroxyphenyl) propane 4,176 g, polyoxyethylene (2.0) -2, 2-bis (4-hydroxyphenyl) propane 3,881 g, 2,253 g of terephthalic acid, 322 g of dodecenyl succinic anhydride, 945 g of trimellitic anhydride and 15 g of dibutyltin oxide were placed in a four-necked flask equipped with a nitrogen introducing tube, a dehydrating tube, a stirrer, and a thermocouple. The mixture was stirred at 220 ° C. and reacted until the softening point measured according to ASTM D36-86 reached 120 ° C. to obtain polyester B. Polyester B had a softening point of 121 ° C, a glass transition point of 65 ° C, and an acid value of 21.0 mgKOH / g.

Resin particle dispersion production example 1 (Production of resin particle dispersion A)
In a 2 liter stainless steel kettle, 390.0 g of polyester A, 210.0 g of polyester B, 45 g of copper phthalocyanine pigment (ECB-301: manufactured by Dainichi Seika Kogyo Co., Ltd.), and an anionic surfactant (“Neo” manufactured by Kao Corporation) Perex G-15 “Sodium dodecylbenzenesulfonate 15 wt% aqueous solution) 20.0 g, nonionic surfactant“ Emulgen 430 (manufactured by Kao) ”polyoxyethylene (26 mol) oleyl ether (HLB: 16.2) 6 0.08 g and 58.5% by weight potassium hydroxide aqueous solution 278.5 g were dispersed at 95 ° C. with stirring at 200 r / min using a chi-type stirrer. The mixture was held for 2 hours under stirring at 200 r / min with a Kai-type stirrer. Subsequently, 1222 g of deionized water was added dropwise at 6 g / min while stirring at 200 r / min with a Kai-type stirrer. The system temperature was maintained at 95 ° C. After cooling to 25 ° C., 28 g of a polymer containing water-soluble oxazoline group “Epocross WS-700 manufactured by Nippon Shokubai Co., Ltd.” is added with a chi-type stirrer at 200 r / min, and the temperature is raised to 95 ° C. The temperature was maintained at 95 ° C. for 1 hour.
After cooling, the resin particle dispersion A was atomized through a 200 mesh (mesh: 105 μm) wire mesh. The resin particles in the obtained resin particle dispersion A had a volume median particle size (D50) of 180 nm, a CV value of 28%, and a solid content concentration of 31% by weight.

Resin particle dispersion production example 2 (Production of resin particle dispersion B)
In a 2 liter stainless steel kettle, 390.0 g of polyester A, 210.0 g of polyester B, and an anionic surfactant (“Neoperex G-15” sodium dodecylbenzenesulfonate 15 wt% aqueous solution manufactured by Kao Corporation) 20. 0 g, nonionic surfactant “Emulgen 430 (manufactured by Kao)” polyoxyethylene (26 mol) oleyl ether (HLB: 16.2) 6.0 g, and 58.5% by weight potassium hydroxide aqueous solution 278.5 g The mixture was dispersed at 95 ° C. with stirring of 200 r / min. The mixture was held for 2 hours under stirring at 200 r / min with a Kai-type stirrer. Subsequently, deionized water was added dropwise at a rate of 6 g / min while stirring at 200 r / min with a Kai-type stirrer. The system temperature was maintained at 95 ° C. After cooling, the resin particle dispersion B was atomized through a 200 mesh (mesh: 105 μm) wire mesh. The resin particles in the obtained resin particle dispersion B had a volume median particle size (D50) of 141 nm, a CV value of 24%, and a solid content concentration of 31% by weight.

Release Agent Dispersion Production Example 1 (Production of Release Agent Dispersion A) In a 1 liter beaker, 400 g of deionized water, an aqueous solution of sodium salt of acrylic acid-maleic acid copolymer as an aqueous solution of sodium polycarboxylate, chemical formula (II), 7.5 g of “Poise 521” manufactured by Kao Corporation, weight average molecular weight: 2.0 × 10 ⁴ , effective concentration 40% by weight) was dissolved, and then carnauba wax (manufactured by Kato Yoko Co., melting point 83) was dissolved therein. 58 g) and paraffin wax HNP-9 (Nihon Seiki Co., Ltd., melting point 75 ° C.) 42 g was added and dispersed. While maintaining the temperature at 90 to 95 ° C., the dispersion was subjected to a dispersion treatment with “Ultrasonic Homogenizer 600W” (manufactured by Nippon Seiki Co., Ltd.) for 30 minutes and then cooled to room temperature (25 ° C.). In addition, the release agent solid content was adjusted to 20% by weight to obtain a release agent dispersion A.

Release agent dispersion production example 2 (Production of release agent dispersion B)
In the release agent dispersion production example 1, instead of paraffin wax HNP-9, paraffin wax HNP-51 (manufactured by Nippon Seiki Co., Ltd., melting point 77 ° C.) was used, and an aqueous sodium salt solution of acrylic acid-maleic acid copolymer In the same manner, except that a sodium polyacrylate aqueous solution (chemical formula (I), “Poise 530” manufactured by Kao Corporation, weight average molecular weight 3.8 × 10 ⁴ , effective concentration 40% by weight) was used instead of An agent dispersion B was obtained.

Release agent dispersion production example 3 (Production of release agent dispersion C)
In Release Agent Dispersion Production Example 1, release agent dispersion C was prepared in the same manner except that ester wax WEP-3 (manufactured by NOF Corporation, melting point 73 ° C.) was used instead of paraffin wax HNP-9. Obtained.

Comparative production example 1
In the release agent dispersion production example 1, 100 g of carnauba wax (manufactured by Kato Yoko Co., Ltd., melting point 83 ° C.) is used as a release agent without using paraffin wax HNP-9, and an acrylic acid-maleic acid copolymer. In the same manner, an aqueous sodium polyacrylate solution (compound of the above formula (I), “Poise 530” manufactured by Kao Corporation, weight average molecular weight 3.8 × 10 ⁴ , effective concentration 40% by weight) was used instead of Although the dispersion treatment was performed, the viscosity increased and a dispersion liquid could not be obtained.

Comparative production example 2
In the release agent dispersion production example 1, dispersion treatment was performed in the same manner using 100 g of paraffin wax HNP-9 (manufactured by Nippon Seiki Co., Ltd., melting point 75 ° C.) without using carnauba wax as the release agent. The release agent and water were separated, and a dispersion was not obtained.

Comparative Production Example 3 (Production of release agent dispersion D)
In the release agent dispersion production example 1, instead of the sodium salt aqueous solution “Poise 521” (manufactured by Kao Corporation) of acrylic acid-maleic acid copolymer, Neoperex G15 (sodium dodecylbenzenesulfonate active ingredient concentration 15%) A release agent dispersion D was obtained in the same manner except that 6.7 g of Kao Corporation was used.

Comparative Production Example 4 (Production of release agent dispersion E)
In the release agent dispersion production example 1, 100 g of carnauba wax (manufactured by Kato Yoko Co., Ltd., melting point 83 ° C.) is used as a release agent without using paraffin wax HNP-9, and an acrylic acid-maleic acid copolymer. The release agent dispersion E was used in the same manner except that 3.6 g latemul ASK (dipotassium alkenyl succinate active ingredient concentration 28%, manufactured by Kao) was used instead of the sodium salt aqueous solution “Poise 521” (manufactured by Kao). Got.

Comparative Production Example 5 (Production of release agent dispersion F)
In the release agent dispersion production example 1, 100 g of paraffin wax HNP-9 (manufactured by Nippon Seiki Co., Ltd., melting point 75 ° C.) is used as a releasing agent without using carnauba wax (manufactured by Kato Yoko Co., Ltd., melting point 83 ° C.). Was replaced with an aqueous sodium salt solution of an acrylic acid-maleic acid copolymer “Poise 521” (manufactured by Kao Corporation), and 3.6 g of latem ASK (active potassium dialkenyl succinate, 28% active ingredient concentration, manufactured by Kao Corporation) was used. Except for the above, release agent dispersion F was obtained in the same manner.

Comparative Production Example 6
In Release Agent Dispersion Production Example 1, the same dispersion treatment was performed using 100 g of carnauba wax (manufactured by Kato Yoko Co., Ltd., melting point 83 ° C.) without using paraffin wax HNP-9 as the release agent. The viscosity increased and a dispersion could not be obtained.

Table 1 shows the compositions and properties of the release agent dispersions A to F obtained in the release agent dispersion production examples 1 to 3 and the comparative production examples 1 to 6, respectively.

Example 1
250 g of resin particle dispersion A, 58 g of deionized water, and 41 g of release agent dispersion A were placed in a 2-liter four-necked flask equipped with a dehydrating tube, a stirrer, and a thermocouple, and mixed at room temperature (25 ° C.). Next, an aqueous solution in which 18.2 g of ammonium sulfate was dissolved in 162 g of deionized water was dropped into this mixture over 30 minutes while stirring with a Kai-type stirrer. Next, the obtained mixed solution was heated up to 55 ° C. and held at 55 ° C. to form aggregated particles having a volume median particle size of 4.0 μm.
Subsequently, a mixed liquid in which 23 g of resin particle dispersion B and 7.5 g of deionized water were mixed as a resin fine particle dispersion was dropped over 60 minutes. This operation was repeated a total of 3 times. Next, a mixture of 28 g of resin particle dispersion A and 9.0 g of deionized water, and an aqueous solution in which 1.5 g of ammonium sulfate is dissolved in 15 g of deionized water are simultaneously added dropwise over 60 minutes. did. This operation was repeated twice in total to obtain a resin fine particle-attached aggregated particle dispersion having a volume median particle size of 5.0 μm.

After adding an aqueous solution obtained by diluting 11.6 g of sodium polyoxyethylene lauryl ether sulfate (Emar E27C, solid content: 28% by weight) with 450 g of deionized water to the obtained resin fine particle adhering aggregated particle dispersion, up to 80 ° C. After raising the temperature over 2 hours and holding for 2 hours, coalescent particles having a volume median particle size of 5.0 μm were obtained. Then, it cooled to room temperature (25 degreeC). During this time, the resin fine particle adhesion aggregated particles changed to coalesced particles.
The obtained coalesced particles were subjected to a filtration step for solid-liquid separation, a drying step, and a washing step to obtain toner particles. With respect to 100 parts by weight of the toner particles, 2.5 parts of hydrophobic silica (manufactured by Nippon Aerosil Co., Ltd .; RY50, number average particle size; 0.04 μm), hydrophobic silica (manufactured by Cabot; Cabo Seal TS720, number average particle size) 0.012 μm) and 0.8 part of organic fine particles (manufactured by Nippon Paint Co., Ltd .; Finesphere P2000, number average particle size; 0.5 μm) were externally added with a Henschel mixer, and a 150 mesh sieve was obtained. The fine particles that passed through were used as cyan toner.

Example 2
A toner was obtained in the same manner as in Example 1 except that 41 g of the release agent dispersion B was used instead of 41 g of the release agent dispersion A.

Example 3
A toner was obtained in the same manner as in Example 1 except that 41 g of the release agent dispersion C was used instead of 41 g of the release agent dispersion A.

Comparative Example 1
A toner was obtained in the same manner as in Example 1 except that 41 g of the release agent dispersion D was used instead of 41 g of the release agent dispersion A.

Comparative Example 2
A toner was obtained in the same manner as in Example 1, except that 24 g of the release agent dispersion E and 17 g of the release agent dispersion F were used instead of 41 g of the release agent dispersion A.

With respect to the toners obtained in Examples 1 to 3 and Comparative Examples 1 and 2, the following methods were used to evaluate the aggregation and temporary fine powder, the state of the supernatant, the fixability and the storage stability in the toner production process. . The results are shown in Table 2.

[The state of fine powder and supernatant during aggregation]
Regarding the agglomeration between the release agent particles and the resin particles during aggregation in the toner manufacturing process, measurement of the particle size distribution of the aggregated particles in the collected aggregated particle dispersion and confirmation of the turbidity of the collected supernatant of the aggregated particle dispersion did. The larger the amount of fine particles (ratio (number%) of particles having a particle diameter of 2 μm or less)) in the particle size distribution of the agglomerated particles, the more the release agent particles are less agglomerated with the resin particles, and the supernatant liquid becomes cloudy Indicates that the release agent is released.
A: The supernatant liquid is transparent. B: The supernatant liquid is slightly cloudy. C: The supernatant liquid is cloudy.

[State of fine powder and supernatant at the same time]
Measurement of the particle size distribution of the coalesced particle dispersion in the collected coalesced particle dispersion and the turbidity of the supernatant of the collected coalesced particle dispersion in the toner production process It confirmed in the same manner as the evaluation method of the state of the supernatant. In the particle size distribution of coalesced particles, the larger the amount of fine powder (ratio (number%) of particles having a particle size of 2 μm or less)), the more release agent particles are released from the agglomerated particles, or they are released at the time of coalescence. When the supernatant liquid becomes cloudy, it indicates that the release agent is liberated.

[Toner fixability evaluation]
An image is output on a high-quality paper (Fuji Xerox Co., Ltd., J paper A4 size) using a commercially available printer (Oki Data Co., Ltd., “ML5400”), and the toner adhesion amount on the paper is 0.45 ± 0.03 mg / A solid image of cm ² was output as an unfixed image with a length of 50 mm, leaving a margin of 5 mm from the top of A4 paper. The fixing device mounted on the printer was modified to have a variable temperature, and fixed at a temperature fixing speed of 34 sheets / minute (A4 vertical direction). The fixability of the obtained fixed image was evaluated by the following tape peeling method.
(Tape peeling method) Cut the mending tape (3M Scotch mending tape 810 width 18mm) into a length of 50mm, lightly affix it to the margin at the top of the fixed image, put a 500g weight and speed One reciprocal pressing was performed at 10 mm / sec. Thereafter, the applied tape was peeled off from the lower end side at a peeling angle of 180 degrees and a speed of 10 mm / sec, the reflection image density before and after tape application was measured according to the measurement method, and the fixing rate was calculated from the following formula.
Fixing rate = (image density after tape peeling / image density before tape application) × 100 tape

When the image density after peeling becomes the same value as the image density before sticking the tape, the fixing rate is 100, and the lower the value, the lower the fixability. When the fixing rate is 90 or more, the fixing property is good.
The test is performed at each fixing temperature in increments of 5 ° C., and the test is performed from a temperature at which a cold offset occurs or a temperature at which the fixing rate is less than 90 to a temperature at which a hot offset occurs. The cold offset refers to a phenomenon in which the toner on the unfixed image does not melt sufficiently when the fixing temperature is low, and the toner adheres to the fixing roller. On the other hand, the hot offset refers to a high fixing temperature. In this case, the phenomenon is that the toner adheres to the fixing roller due to a decrease in the viscoelasticity of the toner on the unfixed image. The occurrence of cold offset or hot offset can be judged again by whether toner adheres to the paper when the fixing roller makes one round. In this test, whether toner adheres to the area 87 mm from the top of the solid image. Judged by no. Here, the hot offset occurrence temperature is a temperature at which hot offset starts to occur, and the maximum fixing temperature is hot offset −5 ° C. The minimum fixing temperature is the minimum temperature among those at which a cold offset does not occur or the fixing rate is 90 or more. In this test, the minimum fixing temperature and the temperature range within which the toner can be fixed (maximum fixing temperature). Temperature-minimum fixing temperature).

[Evaluation of storage stability of toner]
10 g of toner was placed in a 20 ml polybin and left in an open state for 48 hours in an environment of a temperature of 50 ° C. and a relative humidity of 40 Rh%. After standing, the degree of aggregation was measured with a powder tester (manufactured by Hosokawa Micron), and the storage stability was evaluated according to the following criteria according to the following criteria.
The smaller the degree of aggregation, the better the storage stability.
A: The degree of aggregation is less than 10%.
B: The degree of aggregation is 10% or more and less than 20%.
C: The degree of aggregation is 20% or more.
In addition, the aggregation degree using a powder tester was specifically determined as follows.
Three different sieve openings are set in the order of 250 μm in the upper stage, 150 μm in the middle stage, and 75 μm in the lower stage on the powder tester's shaking table, and 2 g of toner is placed on the shaker for 60 seconds, and the remaining toner weight on each sieve. Measure.
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)

According to the production method of the present invention, since aggregation can be controlled with a small particle size at the time of toner production, the toner for electrophotography suitably used for electrophotography, electrostatic recording method, electrostatic printing method, etc. Can be obtained.

Claims

(1) The release agent (A) and the release agent (B) having a melting point 5 ° C. higher than the melting point of the release agent (A) are emulsified in an aqueous medium in the presence of a polycarboxylate. And a step of agglomerating and coalescing the obtained release agent particles and the resin particles.
The method for producing a toner according to claim 1, wherein the release agent (B) has a melting point of 100 ° C. or less.
The method for producing a toner according to claim 1 or 2, wherein the release agent (B) is carnauba wax.
4. The method for producing a toner according to claim 1, wherein the polycarboxylate is a salt of an acrylic acid-maleic acid copolymer.
5. The method for producing a toner according to claim 1, wherein the polycarboxylate is a sodium salt of an acrylic acid-maleic acid copolymer.
6. The method for producing a toner according to claim 1, wherein the polycarboxylate is present in an amount of 0.2 to 15 parts by weight with respect to 100 parts by weight of the total amount of the release agent.
The method for producing a toner according to claim 1, wherein the resin particles contain polyester.
The method for producing a toner according to claim 7, wherein the polyester includes an amorphous polyester.
The method for producing a toner according to claim 1, wherein the releasing agent (A) has a melting point of 60 to 95 ° C.
10. The method for producing a toner according to claim 1, wherein the release agent (A) is an ester wax.
The method for producing a toner according to any one of claims 1 to 9, wherein the release agent (A) is paraffin wax.
An electrophotographic toner obtained by the production method according to any one of claims 1 to 11.