JP6001936B2 - Method for producing toner for electrophotography - Google Patents

Description

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

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, it has been proposed to internally add a release agent to the toner in order to improve low-temperature fixability.
For example, Patent Document 1 discloses that for the purpose of providing an electrophotographic toner that prevents release of release agent particles from a toner composition at the time of toner preparation and is excellent in low-temperature fixability and high-temperature offset resistance. Release agent dispersion for toner containing release agent particles, which comprises a step of mixing a dispersion of a release agent having an acid value of 0.5 to 20 mg KOH / g and a polymer having an oxazoline group A method for producing the liquid is disclosed. Patent Document 2 discloses melting a toner material containing a polyester-containing binder resin and a release agent for the purpose of providing an electrophotographic toner having excellent heat-resistant storage stability and a wide fixing temperature range. A method for producing an electrophotographic toner is disclosed which comprises a step of kneading and emulsifying the obtained melt-kneaded product in an aqueous medium and then adding a polymer having an oxazoline group in an aggregation step or a coalescence step.

JP 2009-133946 A JP 2009-192699 A

  However, in the method described in Patent Document 1, when hydrocarbon wax is used as the release agent, the release agent is sufficiently released from the coalesced particles into the aqueous medium when the toner is manufactured. It cannot be suppressed. Further, even the method described in Patent Document 2 cannot suppress the release of the release agent, and the toner fixability and high-temperature offset resistance are insufficient.

  Even when a wax mixture containing a hydrocarbon wax and an ester wax is used as a release agent, the present invention suppresses the release of the release agent from the coalesced particles, thereby reducing the low-temperature fixability and resistance. The present invention relates to a method for producing an electrophotographic toner excellent in high temperature offset property.

The present invention provides a method for producing an electrophotographic toner having the following steps 1 to 3.
Step 1: A wax mixture containing a hydrocarbon wax and an ester wax having a carboxy group and an acid value of 0.5 mgKOH / g or more is mixed with a polymer having an oxazoline group, and then dispersed in an aqueous medium. Step 2: Obtaining an aqueous dispersion of release agent particles Step 2: Mixing an aqueous dispersion of release agent particles obtained in Step 1 with an aqueous dispersion of resin particles containing a resin having a carboxy group. Step of aggregating to obtain aggregated particles Step 3: Step of coalescing the aggregated particles obtained in step 2 to obtain coalesced particles

  According to the production method of the present invention, it is possible to prevent release of the release agent particles from the toner composition at the time of toner preparation, and to provide an electrophotographic toner that is excellent in low-temperature fixability and high-temperature offset resistance. .

The production method of the present invention includes the following steps 1 to 3.
Step 1: A wax mixture containing a hydrocarbon wax and an ester wax having a carboxy group and an acid value of 0.5 mg KOH / g or more (hereinafter also simply referred to as “ester wax”) is mixed with a heavy oil having an oxazoline group. After mixing with a coalescence (hereinafter also referred to as “oxazoline group-containing polymer”), it is dispersed in an aqueous medium to obtain an aqueous dispersion of release agent particles. Step 2: The release agent obtained in Step 1 The aqueous dispersion of particles and the aqueous dispersion of resin particles containing a resin having a carboxy group are mixed and aggregated to obtain aggregated particles. Step 3: Combine the aggregated particles obtained in Step 2 together. , The step of obtaining coalesced particles

The production method of the present invention suppresses release of the release agent from the resin by reacting the carboxy group of the release agent with the oxazoline group of the oxazoline group-containing polymer and then dispersing the release agent. To do. In the step 1, the carboxy group and the oxazoline group contained in the release agent are mixed by mixing a wax mixture having a carboxy group and a polymer having an oxazoline group, reacting the oxazoline group and the carboxy group, and then emulsifying. It is thought that the reactivity with can be increased.
On the other hand, in Patent Document 1, since the release agent is first emulsified with an emulsifier, the release agent interface is covered with an emulsifier or the like, and the carboxyl group in the release agent and the oxazoline group of the oxazoline-containing polymer It is considered that the reaction is inhibited and a sufficient effect cannot be obtained.

<Step 1>
In Step 1, a wax mixture containing a hydrocarbon wax and an ester wax having a carboxy group and an acid value of 0.5 mgKOH / g or more is mixed with a polymer having an oxazoline group, and then mixed in an aqueous medium. This is a step of dispersing to obtain an aqueous dispersion of release agent particles.

  In the present invention, when producing the toner, from the viewpoint of suppressing the release of the release agent from the toner composition, specifically the coalesced particles, and from the viewpoint of improving the low temperature fixability and the high temperature offset resistance, A wax mixture comprising hydrocarbon wax and ester wax is used.

(Hydrocarbon wax)
Hydrocarbon wax is preferably used as a mold release agent when using crystalline polyester.
As the hydrocarbon wax, at least one selected from low molecular weight polypropylene, low molecular weight polyethylene, low molecular weight polypropylene polyethylene copolymer, microcrystalline wax, paraffin wax, Fischer-Tropsch wax, ceresin and the like can be used. Among these, hydrocarbon wax having 16 to 40 carbon atoms is preferable, and paraffin wax is more preferable from the viewpoint of good releasability when using the toner.
The melting point of the hydrocarbon wax is preferably 50 ° C. or higher, more preferably 60 ° C. from the viewpoint of suppressing the release of the release agent from the toner composition during the production of the toner and improving the high temperature offset resistance. From the viewpoint of improving the low-temperature fixability of the toner, it is preferably 100 ° C. or lower, more preferably 95 ° C. or lower, and still more preferably 90 ° C. or lower. Melting | fusing point can be measured using a differential scanning calorimeter, and can be specifically measured by the method as described in an Example.

(Ester wax)
The ester wax used in the present invention has a carboxy group. By reacting the carboxy group of the ester wax with the oxazoline group of the oxazoline group-containing polymer, release of the release agent from the toner composition, specifically, the coalesced particles can be suppressed.
The acid value of the ester wax used in the present invention is 0.5 mgKOH / g or more, preferably 0.7 mgKOH / g or more, more preferably 1.0 mgKOH / g or more, from the viewpoint of reactivity with the oxazoline group-containing polymer. From the viewpoint of securing the chargeability of the toner, it is preferably 50 mgKOH / g or less, more preferably 20 mgKOH / g or less, still more preferably 17 mgKOH / g or less, more preferably 15 mgKOH / g or less.
The ester wax used in the present invention is selected from plant waxes, ester waxes having natural or synthetic long-chain aliphatic groups, esterified products of acid-modified polyolefin waxes obtained by modifying polyolefins with carboxylic acids, and the like. At least one can be used. As the plant wax, at least one selected from carnauba wax, rice wax, candelilla wax and the like can be used. Among these, carnauba wax is preferable from the viewpoint of suppressing the release of the release agent from the toner composition during the production of the toner and improving the low-temperature fixability and the high-temperature offset resistance.
The melting point of the ester wax is preferably 50 ° C. or more, more preferably 60 ° C. from the viewpoint of suppressing the release agent from being released from the toner composition during the production of the toner and improving the high temperature offset resistance. From the viewpoint of improving the low-temperature fixability, it is preferably 100 ° C. or lower, more preferably 95 ° C. or lower, and still more preferably 90 ° C. or lower. Melting | fusing point can be measured using a differential scanning calorimeter, and can be specifically measured by the method as described in an Example.

  The mass ratio of the hydrocarbon wax to the ester wax in the wax mixture is the mass ratio of the ester wax / hydrocarbon wax, in view of suppressing the release agent from being released from the toner composition when the toner is produced, and at a low temperature. From the viewpoint of improving fixability, it is preferably 5/95 or more, more preferably 10/90 or more, still more preferably 20/80 or more, and from the viewpoint of improving high-temperature offset resistance, preferably 70/30 or less, More preferably, it is 50/50 or less, More preferably, it is 40/60 or less, More preferably, it is 30/70 or less, Preferably it is 5 / 95-70 / 30, More preferably, it is 10 / 90-50 / 50, Furthermore Preferably it is 10 / 90-40 / 60, More preferably, it is 20 / 80-30 / 70.

Although the mixing method of said hydrocarbon wax and ester wax is not specifically limited, For example, the method of mixing after fuse | melting both is preferable.
The amount of the release agent is preferably 0.5 parts by weight or more, more preferably 1 part by weight or more, and more preferably 1.5 parts by weight with respect to 100 parts by weight of the resin having a carboxy group from the viewpoint of low-temperature fixability of the toner. From the viewpoint of suppressing release of the release agent, it is preferably 20 parts by weight or less, more preferably 20 parts by weight or less, more preferably 18 parts by weight or less, and even more preferably 15 parts by weight or less.
The total amount of the above hydrocarbon wax and ester wax in the wax mixture improves the viewpoint of suppressing the release of the release agent from the toner composition during the production of the toner, as well as the low temperature fixability and the high temperature offset resistance. From the viewpoint, when the wax mixture is 100% by mass, it is preferably 80% by mass or more, more preferably 90% by mass or more, and further preferably substantially 100% by mass.

(Oxazoline group-containing polymer)
The oxazoline group-containing polymer can be obtained by polymerizing a polymerizable monomer having an oxazoline group, and if necessary, a polymerizable monomer having an oxazoline group and a polymerizable monomer having the oxazoline group. It can also be obtained by copolymerization of a monomer and a polymerizable monomer copolymerizable. Here, the polymerizable monomer copolymerizable with the polymerizable monomer having an oxazoline group includes both a polymerizable monomer having an oxazoline group and a polymerizable monomer having no oxazoline group. be able to.

  The polymerizable monomer having an oxazoline group is not particularly limited, but 2-vinyl-2-oxazoline, 2-vinyl-4-methyl-2-oxazoline, 2-vinyl-5-methyl-2-oxazoline, Selected from 2-isopropenyl-2-oxazoline, 2-isopropenyl-4-methyl-2-oxazoline, 2-isopropenyl-5-methyl-2-oxazoline, 2-isopropenyl-5-ethyl-2-oxazoline, etc. At least one of the above can be used. Among these, 2-isopropenyl-2-oxazoline is preferable from the viewpoint of availability.

  Among the polymerizable monomers copolymerizable with the polymerizable monomer having an oxazoline group, the polymerizable monomer having no oxazoline group is not particularly limited, but (meth) acrylic acid ester, (meta ) At least selected from acrylate, unsaturated nitrile, unsaturated amide, vinyl ester, vinyl ether, α-olefin, halogen-containing α, β-unsaturated aliphatic hydrocarbon, α, β-unsaturated aromatic hydrocarbon, etc. One can be used.

  The content of the oxazoline group in the oxazoline group-containing polymer is preferably 0.1 mmol / g or more, more preferably from the viewpoint of suppressing the release of the release agent from the resin having a carboxy group when the toner is produced. Is 0.5 mmol / g or more, and preferably 0.05 mol / g or less, more preferably 0.01 mol / g or less, from the viewpoint of suppressing release of the release agent (reaction density).

  The number average molecular weight of the oxazoline group-containing polymer is not particularly limited, but is preferably 500 or more, more preferably 1,000 or more from the viewpoint of reaction efficiency of the oxazoline group, and preferably 2, from the viewpoint of handleability. It is 1,000,000 or less, more preferably 1,000,000 or less. If the number average molecular weight is 500 or more, a sufficient crosslinking reaction with the release agent particles or the resin particles is performed. If the number average molecular weight is 2,000,000 or less, the viscosity of the polymer becomes an appropriate value and handling is possible. It becomes easy.

  As a commercially available product generally used as an oxazoline group-containing polymer, EPOCROSS WS series (water-soluble type), K series (emulsion type) manufactured by Nippon Shokubai Co., Ltd. can be used.

(Mixing of wax mixture and oxazoline group-containing polymer)
The oxazoline group-containing polymer is mixed with the wax mixture after preparing the above wax mixture.
A means for mixing the wax mixture and the oxazoline group-containing polymer is not particularly limited, and a homogenizer having a strong shearing force, a pressure discharge type homogenizer, an ultrasonic disperser, or the like can be used. Homomixer, Disper (trade name, manufactured by Primix Co., Ltd.), Claremix (trade name, manufactured by M Technique Co., Ltd.), Cavitron (trade name, manufactured by Taihei Kiko Co., Ltd.), etc. it can. In addition, when using a disper, it is preferable to perform stirring for 5 minutes or more in the state in which the whole is mixed uniformly.

  The temperature at which the wax mixture and the oxazoline group-containing polymer are mixed is preferably 50 ° C. or more, more preferably 55 ° C., from the viewpoint of efficiently reacting the oxazoline group of the oxazoline group-containing polymer and the carboxy group of the ester wax. From the viewpoint of operability, it is preferably 99 ° C. or lower, more preferably 98 ° C. or lower, and still more preferably 96 ° C. or lower.

The mixing ratio of the wax mixture and the oxazoline group-containing polymer is the number of moles of oxazoline groups of the oxazoline group-containing polymer from the viewpoint of suppressing the release of the release agent from the toner composition when the toner is produced. The ratio of the number of moles of the carboxy group of the ester wax to that of the ester wax (carboxy group / oxazoline group) is preferably 1/20 or more, more preferably 1/10 or more, and even more preferably 1/5 or more. From the viewpoint of avoidance, it is preferably 10/1 or less, more preferably 8/1 or less, and further preferably 5/1 or less.

(Emulsification of release agent)
The wax mixture is mixed with the oxazoline group-containing polymer and then dispersed in an aqueous medium to obtain an aqueous dispersion of release agent particles. Preferably, after the wax mixture is mixed with the oxazoline group-containing polymer, it is dispersed in an aqueous medium in the presence of an emulsifier to obtain a preliminary emulsion, and the preliminary emulsion is further heated to a temperature equal to or higher than the melting point of the wax. While finely dispersing using a high-pressure emulsifying disperser. Thereby, an aqueous dispersion of release agent particles having a volume median particle diameter (D ₅₀ ) of preferably 1 μm or less can be obtained.

  As the aqueous medium used for the dispersion of the wax, an aqueous medium used for emulsification of the resin described later can be used. However, from the viewpoint of environmental properties and ease of addition at the time of toner preparation, deionized water or distilled water is used. Water is preferred.

  Although it does not specifically limit as an emulsifier, At least 1 sort (s) of surfactant chosen from anionic surfactant, a cationic surfactant, a nonionic surfactant, and a polymer dispersing agent can be used.

  As the anionic surfactant, at least one selected from alkyl sulfate ester salts, polyoxyethylene alkyl ether sulfate ester salts, dipotassium alkenyl succinate, sodium fatty acid having 8 to 22 carbon atoms and the like can be used.

  As the cationic surfactant, at least one selected from alkyltrimethylammonium chloride, dialkyldimethylammonium chloride and the like can be used.

  Nonionic surfactants include polyoxyethylene alkyl ethers having 8 to 22 carbon atoms, polyoxyethylene alkylphenyl ethers, polyoxyethylene polyoxypropylene glycols, sorbitan fatty acid esters (sorbitan monostearate, sorbitan monopalmitate, etc.) At least one selected from sucrose fatty acid esters (sugar esters) and the like can be used.

  Polymeric dispersants include polyvinyl alcohol, cellulose compounds (methyl cellulose, ethyl cellulose, hydroxy cellulose, carboxymethyl cellulose, hydroxyethyl cellulose, carboxyethyl cellulose, etc.), polyacrylates, polymethacrylates, polyacrylic acid-styrene copolymer salts At least one selected from among them can be used.

  From the viewpoint of low reactivity with the oxazoline group of the oxazoline group-containing polymer, an anionic surfactant or a nonionic surfactant is preferable, and a nonionic surfactant is more preferable. As the nonionic surfactant, sucrose fatty acid ester is preferable, and sucrose stearate is more preferable. As a commercial product of sucrose fatty acid ester, Ryoto Sugar Ester (trade name) manufactured by Mitsubishi Chemical Foods Co., Ltd. can be used.

  The addition amount of the emulsifier (surfactant) is preferably 0.1 parts by mass or more, more preferably 0.3 parts by mass or more, and more preferably 0.3 parts by mass or more with respect to 100 parts by mass of the wax mixture, from the viewpoint of improving the emulsion stability. The amount is preferably 0.5 parts by mass or more, and preferably 10 parts by mass or less, more preferably 7 parts by mass or less, and still more preferably 5 parts by mass or less from the viewpoint of reducing the load of cleaning the toner.

  The stirring means used for the preparation of the preliminary emulsion is not particularly limited, and a homogenizer having a strong shearing force, a pressure discharge type homogenizer, an ultrasonic disperser, or the like can be used. Homomixer, Disper (trade name, manufactured by Primix Co., Ltd.), Claremix (trade name, manufactured by M Technique Co., Ltd.), Cavitron (trade name, manufactured by Taihei Kiko Co., Ltd.), etc. it can. In addition, when using a disper, it is preferable to perform stirring for 5 minutes or more in the state in which the whole is mixed uniformly.

Further, the obtained preliminary emulsion is finely dispersed using a high-pressure emulsifying disperser while being heated to a temperature equal to or higher than the melting point of the wax to obtain an aqueous dispersion of release agent particles.
The method for bringing the preliminary emulsion to a temperature equal to or higher than the melting point of the wax is not particularly limited, but after obtaining the preliminary emulsion, at least a part of the flow path leading to the high-pressure dispersion part of the high-pressure emulsion disperser, A method in which the temperature is at least the melting point of the wax is preferred. Specific examples include a method of heating the flow path from the inside and outside with a jacket or a heating medium, a method of adding warm water or the like to the preliminary emulsion, a method of raising the temperature by infrared rays, microwaves, induction heating, or the like. Among these, a method of immersing the flow path of the high-pressure emulsification disperser in a heat medium such as heated oil or hot water is particularly preferable. In this case, the temperature of the heat medium is preferably set higher by 5 to 30 ° C., preferably 10 to 25 ° C., and more preferably 15 to 20 ° C. higher than the melting point of the wax. Moreover, it is preferable to heat a flow path just before the high pressure dispersion part which performs a high pressure dispersion process.

  The high-pressure emulsifying disperser that can be used is not particularly limited, but from the viewpoint of obtaining particles having a particle size of 1 μm or less and the ease of handling operation, Microfluidizer (manufactured by Mizuho Industry Co., Ltd.), Ultimateizer (Co., Ltd.) Sugino Machine), Nanomizer (Yoshida Kikai Kogyo Co., Ltd.), etc. can be used. As the high-pressure dispersion unit of the disperser, any type such as a counter collision type and a penetration type can be used, but is not particularly limited.

The pressure during high-pressure emulsification of the preliminary emulsion is preferably 5 MPa or more, more preferably 10 MPa or more, still more preferably 20 MPa or more, from the viewpoint of the particle size and dispersibility of the obtained release agent particles. From the viewpoint, it is preferably 200 MPa or less, more preferably 180 MPa or less, and still more preferably 150 MPa or less.
About the frequency | count of a process, although it can select suitably according to the said process pressure, the particle size of the mold release agent particle | grains, etc. which are obtained, Preferably it is 1-10 times, More preferably, it is 2-5 times.

It is preferable to cool the aqueous dispersion of release agent particles to room temperature (20 ° C.) after fine dispersion using a high-pressure emulsifying disperser.
The cooling method is not particularly limited, and any of a method of cooling from the inside and outside of the tube and a method of adding cold water directly to the dispersion is possible. In addition, since a dispersion having a particle size of 1 μm or less is usually stable, a method in which the dispersion is once received in a container and then cooled with a jacket or the like under stirring is also possible.

From the viewpoints of emulsification and productivity, the solid content concentration of the release agent at the time of dispersing the release agent particles in the aqueous dispersion is preferably 5% by mass or more, more preferably 10% by mass or more, and further preferably 15% by mass. % Or more, preferably 40% by mass or less, more preferably 35% by mass or less.
From the viewpoint of dispersibility in the toner, the volume median particle size (D ₅₀ ) of the release agent particles in the obtained aqueous dispersion is preferably 1 μm or less, more preferably 0.01 to 0. .9 μm, more preferably 0.05 to 0.8 μm. The volume median particle size of the release agent particles can be measured using a particle size distribution measuring device, and specifically can be measured by the method described in the examples.

<Step 2>
Step 2 is a step in which the aqueous dispersion of release agent particles obtained in Step 1 and the aqueous dispersion of resin particles containing a resin having a carboxy group are mixed and aggregated to obtain aggregated particles.
Step 2 preferably includes step 2-1 below, and more preferably includes step 2-1 and step 2-2 from the viewpoint of suppressing release of the release agent. By including the steps 2-1 and 2-2, the obtained toner particles become core-shell particles including the resin particles (A) in the core portion and the resin particles (B) in the shell portion.
In the present invention, the resin having a carboxy group is a resin used in Step 2-1, and includes both the crystalline polyester (a1) and the amorphous polyester (a2).
Step 2-1: An aqueous dispersion of release agent particles obtained in Step 1, an aqueous dispersion of resin particles (A) containing a resin having a carboxy group, and an aggregating agent are mixed in an aqueous medium. Step 2-2 for agglomerating and obtaining aggregated particles (1): water dispersion of resin particles (B) containing amorphous polyester (b) in aggregated particles (1) obtained in step 2-1 Adding liquid to obtain aggregated particles (2)

[Resin particles (A)]
(Resin having carboxyl group)
As the resin having a carboxyl group, a known resin used for toner, for example, polyester, styrene-acrylic copolymer, epoxy resin, polycarbonate, polyurethane and the like can be used. From the viewpoint of toner fixing property and durability. Therefore, it is preferable that polyester is included. The content of the polyester in the resin having a carboxyl group is preferably 60% by mass or more, more preferably 70% by mass or more, and still more preferably 80% in the resin having a carboxyl group, from the viewpoint of toner fixability and durability. It is at least 100% by weight, more preferably 100% by weight.
The resin particles (A) containing a resin having a carboxy group contain both the crystalline polyester (a1) and the amorphous polyester (a2) from the viewpoint of improving the low-temperature fixability and high-temperature offset resistance of the toner. It is preferable.

(Crystalline polyester (a1))
In the present invention, the resin particles (A) preferably contain the crystalline polyester (a1) from the viewpoint of low-temperature fixability of the toner.

The crystalline polyester (a1) used in the present invention is obtained by condensing an alcohol component containing an α, ω-alkanediol having 10 to 12 carbon atoms and an acid component containing an aliphatic dicarboxylic acid from the viewpoint of low-temperature fixability of the toner. It is preferably obtained by polymerization.
In the present invention, “crystalline polyester” means the ratio between the softening point and the maximum endothermic peak temperature measured by a differential scanning calorimeter (DSC), (softening point (° C.)) / (Maximum endothermic peak temperature (° C.)). The crystallinity index defined by is from 0.6 to 1.4, preferably from 0.8 to 1.3 from the viewpoint of low-temperature fixability of the toner, and from 0.9 to 1.2 Is more preferable, and 0.9 to 1.1 is still more preferable.
The crystalline polyester (a1) preferably has a carboxy group at the molecular end from the viewpoint of facilitating emulsification of the resin particle dispersion and improving dispersion stability.

From the viewpoint of improving the storage stability of the toner, the melting point of the crystalline polyester (a1) is preferably 50 ° C. or higher, more preferably 55 ° C. or higher, further preferably 60 ° C. or higher, further preferably 65 ° C. or higher. From the viewpoint of improving the low temperature fixability, 100 ° C. or lower is preferable, 97 ° C. or lower is more preferable, 95 ° C. or lower is further preferable, and 90 ° C. or lower is further preferable.
From the viewpoint of improving the storage stability of the toner, the softening point of the crystalline polyester (a1) is preferably 50 ° C. or higher, more preferably 60 ° C. or higher, still more preferably 65 ° C. or higher, and further preferably 70 ° C. or higher. From the viewpoint of improving the low temperature fixability, 140 ° C. or lower is preferable, 120 ° C. or lower is more preferable, 110 ° C. or lower is further preferable, and 100 ° C. or lower is further preferable.
The acid value of the crystalline polyester (a1) is preferably 3 mgKOH / g or more, more preferably 4 mgKOH / g or more, from the viewpoint of improving the dispersion stability of the resin particle dispersion and the reactivity with the oxazoline group-containing polymer. 5 mgKOH / g or more is more preferable, 6 mgKOH / g or more is more preferable, and from the viewpoint of securing the chargeability of the toner, 30 mgKOH / g or less is preferable, 25 mgKOH / g or less is more preferable, 23 mgKOH / g or less is further preferable, and 20 mgKOH / g or less. More preferably, it is g or less.
In addition, crystalline polyester (a1) can be used individually or in combination of 2 or more types.
In this invention, melting | fusing point and softening point of crystalline polyester (a1) are calculated | required by the method of an Example description. When using 2 or more types together, melting | fusing point, a softening point, and a number average molecular weight are calculated | required by the method as described in an Example using the mixture mixed by the ratio which uses all the crystalline polyester (a1).

The crystalline polyester (a1) can be produced by subjecting an alcohol component containing an α, ω-alkanediol having 10 to 12 carbon atoms and an acid component containing an aliphatic dicarboxylic acid to a condensation polymerization reaction. A catalyst can be preferably used in the polycondensation reaction.
From the viewpoint of the low-temperature fixability of the toner and the image density of the printed matter, the aliphatic dicarboxylic acid is preferably succinic acid, and the acid component preferably contains 70 to 100 mol%, preferably 90 to 100 mol%. Is more preferable, and it is still more preferable that it is 100 mol%.
Examples of the acid component other than succinic acid include aliphatic dicarboxylic acids other than succinic acid, alicyclic dicarboxylic acids, aromatic dicarboxylic acids, and trivalent or higher polyvalent carboxylic acids. From the viewpoint of improving the quality, aliphatic dicarboxylic acids other than succinic acid are preferred.
The acid component includes not only a free acid but also an anhydride that decomposes during the reaction to produce an acid, and an alkyl ester having 1 to 3 carbon atoms.
These can be used alone or in combination of two or more.

From the viewpoint of further improving the low-temperature fixability of the toner, the alcohol component preferably contains 70 to 100 mol%, more preferably 90 to 100 mol% of α, ω-alkanediol having 10 to 12 carbon atoms. More preferably, it is 100 mol%.
Examples of the α, ω-alkanediol having 10 to 12 carbon atoms include 1,10-decanediol and 1,12-dodecanediol. Among these, from the viewpoint of improving the low-temperature fixability of the toner, 12-dodecanediol is preferred.
The α, ω-alkanediol having 10 to 12 carbon atoms can be used alone or in combination of two or more.
Examples of the alcohol component other than the α, ω-alkanediol having 10 to 12 carbon atoms include aliphatic diols other than the α, ω-alkanediol having 10 to 12 carbon atoms, aromatic diols, hydrogenated products of bisphenol A, and trivalent compounds. The above polyhydric alcohols and the like can be mentioned. Among them, aliphatic diols are preferable from the viewpoint of promoting crystallization of polyester and improving low-temperature fixability of the toner. The average carbon number of the alcohol component is preferably 6 to 14, more preferably 8 to 12, and still more preferably 10 to 12, from the viewpoint of low-temperature fixability of the toner.

  As a combination of an acid component and an alcohol component, from the viewpoint of low-temperature fixability of the toner, an acid component containing 70 to 100 mol% of succinic acid and an α, ω-alkanediol having 10 to 12 carbon atoms are contained in an amount of 70 to 100 mol%. A combination with an alcohol component is preferable, and a combination of succinic acid and an α, ω-alkanediol having 10 to 12 carbon atoms is more preferable.

From the viewpoint of improving the efficiency of the condensation polymerization reaction, the catalyst is preferably a tin compound or a titanium compound, more preferably a tin compound, and further preferably di (2-ethylhexanoic acid) tin or dibutyltin oxide.
Examples of the titanium compound include titanium diisopropylate bistriethanolamate.
0.01-1 mass part is preferable with respect to 100 mass parts of total amounts of an acid component and an alcohol component, and, as for the usage-amount of a catalyst, 0.1-0.6 mass part is more preferable.

  The polycondensation reaction is preferably carried out by putting an acid component and an alcohol component in a reaction vessel and maintaining the reaction at 140 to 200 ° C. for 5 to 15 hours. Further, after that, the catalyst is added and the reaction is allowed to proceed at 140 to 200 ° C. for 1 to 5 hours, and the reaction is preferably carried out under the condition that the pressure is reduced to 5.0 to 20 kPa and maintained for 1 to 10 hours.

(Amorphous polyester (a2))
The resin particles (A) preferably further contain an amorphous polyester (a2) from the viewpoint of improving the heat-resistant storage stability and chargeability while maintaining the low-temperature fixability of the toner and preventing high-temperature offset.
In the present invention, the “amorphous polyester” is a resin having a crystallinity index of more than 1.4 or less than 0.6. The amorphous polyester (a2) preferably has a crystallinity index of less than 0.6 or more than 1.4 and 4 or less, more preferably less than 0.6, from the viewpoint of low-temperature fixability of the toner. It is 1.5 or more and 4 or less, More preferably, it is less than 0.6 or 1.5 or more and 3 or less, More preferably, it is less than 0.6 or 1.5 or more and 2 or less. The crystallinity index can be appropriately determined depending on the type and ratio of raw material monomers, production conditions (eg, reaction temperature, reaction time, cooling rate), and the like.
The amorphous polyester (a2) preferably has a carboxy group at the molecular end from the viewpoint of facilitating emulsification of the resin particle dispersion and enhancing dispersion stability.

  The amorphous polyester (a2) can be produced by subjecting an acid component and an alcohol component to a polycondensation reaction in the same manner as the crystalline polyester (a1).

Examples of the acid component include dicarboxylic acids and trivalent or higher polyvalent carboxylic acids, and among them, dicarboxylic acids are preferable.
Specific examples of the dicarboxylic acid include succinic acid, phthalic acid, isophthalic acid, terephthalic acid substituted with an alkyl group having 1 to 20 carbon atoms or an alkenyl group having 2 to 20 carbon atoms such as dodecyl succinic acid, dodecenyl succinic acid, and octenyl succinic acid. Acid, sebacic acid, fumaric acid, maleic acid, adipic acid, azelaic acid, succinic acid, cyclohexanedicarboxylic acid and the like can be mentioned, among which fumaric acid, dodecenyl succinic acid and terephthalic acid are preferable, and dodecenyl succinic acid and terephthalic acid are more preferable.
Specific examples of the trivalent or higher polyvalent carboxylic acid include trimellitic acid, 2,5,7-naphthalenetricarboxylic acid, pyromellitic acid, and the like. Among these, from the viewpoint of offset resistance, trimellitic acid and its Acid anhydrides are preferred.
An acid component can be used individually or in combination of 2 or more types. The acid component includes not only a free acid but also an anhydride that decomposes during the reaction to produce an acid, and an alkyl ester having 1 to 3 carbon atoms.
The amorphous polyester (a2) contains a trivalent or higher polyvalent carboxylic acid and an acid anhydride or an alkyl ester thereof, preferably trimellitic acid or an anhydride thereof from the viewpoint of high temperature offset resistance of the toner. It is preferable to use at least one amorphous polyester obtained by using an acid component.

Examples of the alcohol component include aliphatic diols having 2 to 12 carbon atoms in the main chain, aromatic diols, hydrogenated products of bisphenol A, trihydric or higher polyhydric alcohols, and the like. Specific examples of the trihydric or higher polyhydric alcohol include glycerin and pentaerythritol.
Among these, it is preferable to use an aromatic diol from the viewpoint of obtaining amorphous polyester, and polyoxypropylene-2,2-bis (4-hydroxyphenyl) propane, polyoxyethylene-2,2-bis ( It is more preferable to use an alkylene (2 to 3 carbon) oxide adduct (average number of added moles of 1 to 16) of bisphenol A such as 4-hydroxyphenyl) propane.
An alcohol component can be used individually or in combination of 2 or more types.

The glass transition point of the amorphous polyester (a2) is preferably 50 ° C. or higher, more preferably 55 ° C. or higher from the viewpoint of high-temperature offset resistance and storage stability, and 70 ° C. or lower from the viewpoint of low-temperature fixability of the toner. Is preferable, 68 ° C. or lower is more preferable, and 66 ° C. or lower is further preferable.
The softening point of the amorphous polyester (a2) is preferably 70 ° C. or higher, more preferably 90 ° C. or higher, particularly preferably 100 ° C. or higher, from the viewpoint of high temperature offset resistance and storage stability, and the low temperature fixability of the toner. From the viewpoint, 165 ° C. or lower is preferable, 140 ° C. or lower is more preferable, and 130 ° C. or lower is particularly preferable.
In addition, when using 2 or more types of amorphous polyesters (a2) in mixture, the glass transition point and the softening point are described in the examples as a mixture of 2 or more types of amorphous polyesters (a2). The value obtained by the method.

The number average molecular weight of the amorphous polyester (a2) is preferably from 1,000 to 50,000, more preferably from 1,500 to 10,000, from the viewpoint of low-temperature fixability and high-temperature offset resistance of the toner, 000 to 8,000 is more preferable, and 2,000 to 4,000 is more preferable.
The acid value of the amorphous polyester (a2) is preferably 6 mgKOH / g or more, more preferably 10 mgKOH / g or more, from the viewpoint of improving the dispersion stability of the resin particle dispersion and the reactivity with the oxazoline group-containing polymer. 15 mgKOH / g or more is more preferable, and from the viewpoint of securing the chargeability of the toner, 35 mgKOH / g or less is preferable, and 30 mgKOH / g or less is more preferable.

  The amorphous polyester (a2) preferably contains two kinds of polyesters having different softening points from the viewpoint of low-temperature fixability and high-temperature offset resistance of the toner. When two types of polyesters having different softening points are designated as polyesters (a2-1) and (b-2), the softening point of one polyester (a2-1) is preferably 70 ° C. or higher and lower than 115 ° C., and the other polyester The softening point of (a2-2) is preferably 115 ° C. or higher and 165 ° C. or lower. The mass ratio ((a2-1) / (a2-2)) between the polyester (a2-1) and the polyester (a2-2) is preferably 10/90 to 90/10, and preferably 50/50 to 90/10. More preferred.

  In addition, in this invention, what modified | denatured each of crystalline polyester and amorphous polyester can be used in the range which does not impair the effect. Examples of methods for modifying the polyester include grafting with phenol, urethane, epoxy, etc. by the methods described in JP-A-11-133668, JP-A-10-239903, JP-A-8-20636, and the like. Examples thereof include a method of forming a block and a method of forming a composite resin having two or more resin units including a polyester unit.

The total amount of the crystalline polyester (a1) and the amorphous polyester (a2) in the resin particles (A) is preferably in the resin constituting the resin particles (A) from the viewpoint of low temperature fixability and high temperature offset resistance of the toner. 50-100 mass%, More preferably, it is 80-100 mass%, More preferably, it is 90-100 mass%, Most preferably, it is substantially 100 mass%.
The mass ratio ((a1) / (a2)) between the crystalline polyester (a1) and the amorphous polyester (a2) in the resin particles (A) is 5/95 or more from the viewpoint of low-temperature fixability of the toner. It is preferably 10/90 or more, more preferably 13/87 or more, still more preferably 15/85 or more, and preferably 50/50 or less from the viewpoint of storage stability of the toner, 60 or less is more preferable, 30/70 or less is more preferable, 25/75 or less is further preferable, and 20/80 or less is still more preferable.

  The resin particles (A) may contain a release agent and a charge control agent as long as the effects of the present invention are not impaired. Moreover, you may contain additives, such as reinforcement fillers, such as a fibrous material, antioxidant, and anti-aging agent, as needed.

In addition, the resin particles (A) may be particles composed only of a resin or may be colorant-containing resin particles containing a colorant. From the viewpoint of sharpening the particle size distribution of the toner, the colorant It is preferable that it is a coloring agent containing resin particle containing a coloring agent.
When the resin particles (A) are colorant-containing resin particles, the content of the colorant is 1 to 20 masses with respect to 100 mass parts of the resin constituting the resin particles (A) from the viewpoint of the image density of the toner. Part is preferable, and 5 to 10 parts by mass is more preferable.

(Coloring agent)
The colorant used in the present invention may be used as a colorant particle in an aqueous medium by surface treatment or use of a dispersant, or may be used by being contained in resin particles such as resin particles (A). From the viewpoint of sharpening the particle size distribution of the toner, the resin particles (A) are preferably used.
As the colorant, pigments and dyes are used, and pigments are preferable from the viewpoint of image density of the toner.
Specific examples of the pigment include carbon black, inorganic composite oxide, chrome yellow, benzidine yellow, brilliantamine 3B, brilliantamine 6B, Bengal, aniline blue, ultramarine blue, copper phthalocyanine, phthalocyanine green, and the like. Phthalocyanine is preferred.
Specific examples of the dye include acridine series, azo series, benzoquinone series, azine series, anthraquinone series, indigo series, phthalocyanine series, and aniline black series.
A coloring agent can be used individually by 1 type or in combination of 2 or more types.

(Production of dispersion of resin particles (A))
The dispersion of the resin particles (A) contains the resin particles (A) by dispersing the above-mentioned optional components such as the crystalline polyester (a1), the amorphous polyester (a2), and the colorant in an aqueous medium. It is preferable to produce by a method obtained as a dispersion.
Examples of a method for obtaining a dispersion include a method in which a resin or the like is added to an aqueous medium and a dispersion treatment is performed using a disperser or the like, and a method in which an aqueous medium is gradually added to a resin or the like to perform phase inversion emulsification. From the viewpoint of low-temperature fixability of the toner, a method using phase inversion emulsification is preferred. Hereinafter, a method by phase inversion emulsification will be described.

First, the above-mentioned optional components such as crystalline polyester (a1), amorphous polyester (a2), alkaline aqueous solution, and colorant are melted and mixed to obtain a resin mixture.
In mixing, it is preferable to add a surfactant from the viewpoint of the emulsion stability of the resin.

  Examples of the alkali in the alkaline aqueous solution include hydroxides of alkali metals such as potassium hydroxide and sodium hydroxide, and ammonia. From the viewpoint of improving the dispersibility of the resin, potassium hydroxide and sodium hydroxide are preferable. . Moreover, 1-30 mass% is preferable, as for the density | concentration of the alkali in alkaline aqueous solution, 1-25 mass% is more preferable, and 1.5-20 mass% is still more preferable.

  Examples of the surfactant include nonionic surfactants, anionic surfactants, cationic surfactants, etc. Among them, nonionic surfactants are preferable, and nonionic surfactants and anionic surfactants or It is more preferable to use a cationic surfactant in combination, and it is more preferable to use a nonionic surfactant and an anionic surfactant in combination from the viewpoint of sufficiently emulsifying the resin.

  The content of the surfactant is preferably 20 parts by mass or less, more preferably 15 parts by mass or less, still more preferably 0.1 to 10 parts by mass with respect to 100 parts by mass of the resin constituting the resin particles (A). 0.5-10 mass parts is still more preferable.

  As a method for obtaining the resin mixture, the crystalline polyester (a1), the amorphous polyester (a2), the alkaline aqueous solution, and the above optional components, preferably a surfactant, are placed in a container and stirred with a stirrer while the resin is mixed. A method of melting and uniformly mixing is preferable.

  The temperature at which the resin is melted and mixed is preferably at least the glass transition point of the amorphous polyester (a2), and more preferably at least the melting point of the crystalline polyester (a1) from the viewpoint of obtaining homogeneous resin particles. .

Next, an aqueous medium is added to the resin mixture and phase inversion is performed to obtain a dispersion containing resin particles (A).
The aqueous medium is preferably composed mainly of water, and the water content in the aqueous medium is preferably 80% by mass or more, more preferably 90% by mass or more, still more preferably 95% by mass or more, and substantially 100% by mass. Is more preferable. As water, deionized water or distilled water is preferably used.
As components other than water, organic solvents that dissolve in water such as aliphatic alcohols having 1 to 5 carbon atoms; dialkyl (carbon numbers 1 to 3) ketones such as acetone and methyl ethyl ketone; and cyclic ethers such as tetrahydrofuran are used.

  The temperature at which the aqueous medium is added is preferably at least the glass transition point of the amorphous polyester (a2), and more preferably at least the melting point of the crystalline polyester (a1) from the viewpoint of obtaining homogeneous resin particles.

  The addition rate of the aqueous medium is from 0.1 to 50 parts by mass / 100 parts by mass of the resin constituting the resin particles (A) until the phase inversion is completed from the viewpoint of making the resin particles have a small particle size. Preferably, it is 0.1 to 30 parts by weight / minute, more preferably 0.5 to 10 parts by weight / minute, and 0.5 to 5 parts by weight / minute. Is more preferable. There is no restriction | limiting in the addition rate of the aqueous medium after phase inversion.

The use amount of the aqueous medium is preferably 100 to 2000 parts by mass, and 150 to 1500 parts by mass with respect to 100 parts by mass of the resin constituting the resin particles (A) from the viewpoint of obtaining uniform aggregated particles in the subsequent aggregation step. More preferred is 150 to 500 parts by mass. From the viewpoints of stability and ease of handling of the obtained resin particle dispersion, the solid content concentration is preferably 7 to 50% by mass, more preferably 10 to 40% by mass, and still more preferably 20 to 40% by mass, More preferably, it is 25-35 mass%. In addition, solid content is the total amount of non-volatile components, such as resin and surfactant.
The dispersion of the obtained resin particles (A) is mixed with the oxazoline group-containing polymer from the viewpoint of suppressing the release agent from being released into the aqueous medium from the resin having a carboxy group in Step 3 described later. It is preferable.

The volume median particle size of the resin particles (A) in the dispersion containing the obtained resin particles (A) is preferably 0.02 to 2 μm. From the viewpoint of obtaining a toner capable of obtaining a high quality image, 0.02 to 1.5 μm is preferable, 0.05 to 1 μm is more preferable, and 0.05 to 0.5 μm is still more preferable. Here, the volume-median particle size is a particle size at which the cumulative volume frequency calculated by the volume fraction is 50% calculated from the smaller particle size.
Further, the coefficient of variation (CV value) (%) of the particle size distribution of the resin particles is preferably 40% or less, more preferably 35% or less, and more preferably 30% from the viewpoint of obtaining a toner capable of obtaining a high-quality image. The following is more preferable. The CV value is a value represented by the following formula, and is specifically obtained by the method described in the examples.
CV value (%) = [standard deviation of particle size distribution (μm) / volume average particle size (μm)] × 100

[Resin particles (B)]
In the present invention, the resin particles (B) preferably contain the amorphous polyester (b) from the viewpoints of low-temperature fixability and high-temperature offset resistance of the toner, and particles consisting essentially of the amorphous polyester (b). It is preferable that
The preferable monomer composition and physical properties of the amorphous polyester (b) are the same as those of the amorphous polyester (a2). The amorphous polyester (b) may be the same as or different from the amorphous polyester (a2).
The dispersion of the resin particles (B) is preferably not mixed with the oxazoline group-containing polymer from the viewpoint of chargeability of the toner.

  The amorphous polyester (b) may be used alone or in combination of two or more, and contains two types of polyesters having different softening points from the viewpoint of low-temperature fixability and high-temperature offset resistance of the toner. Is preferred.

<Step 2-1>
Step 2-1 mixes an aqueous dispersion of release agent particles obtained in Step 1, an aqueous dispersion of resin particles (A) containing a resin having a carboxy group, and an aggregating agent in an aqueous medium. And agglomerating to obtain aggregated particles (1).
In this step, first, the resin particles (A) and the release agent particles are mixed in an aqueous medium to obtain a mixed dispersion.
In addition, although it is preferable to mix a colorant as an arbitrary component, the colorant may be mixed as a separate particle by itself, or may be contained in the resin particles (A). Therefore, it is preferably contained in the resin particles (A).
In this step, resin particles other than the resin particles (A) may be mixed.
There is no restriction | limiting in order of mixing, You may add any in order and may add simultaneously.

In the mixed dispersion, the resin particles (A) (solid content) are preferably 10 to 40% by mass, and more preferably 20 to 30% by mass. The aqueous medium is preferably 60 to 90% by mass, and more preferably 70 to 80% by mass.
Moreover, 1-20 mass parts is preferable with respect to 100 mass parts of resin which comprises a resin particle (A) from a viewpoint of image density, and, as for a coloring agent, 3-15 mass parts is more preferable.
The release agent particles (solid content) are preferably 1 to 20 parts by mass, and 2 to 15 parts by mass with respect to 100 parts by mass in total of the resin and the colorant, from the viewpoints of toner releasability and chargeability. More preferred.
The mixing temperature is preferably 0 to 40 ° C. from the viewpoint of aggregation control.

Next, the particles in the mixed dispersion are aggregated to obtain a dispersion of aggregated particles (1). It is preferable to add a flocculant for efficient aggregation.
As the flocculant, a quaternary salt cationic surfactant, an organic flocculant such as polyethyleneimine; and an inorganic flocculant such as an inorganic metal salt, an inorganic ammonium salt, or a bivalent or higher metal complex are used.
Examples of the inorganic metal salt include metal salts such as sodium sulfate, sodium chloride, calcium chloride and calcium nitrate, and inorganic metal salt polymers such as polyaluminum chloride and polyaluminum hydroxide. Examples of the inorganic ammonium salt include ammonium sulfate, ammonium chloride, ammonium nitrate and the like, and ammonium sulfate is more preferable. The valence of the salt is not particularly limited, and may be monovalent or divalent or higher.
The use amount of the flocculant is preferably 50 parts by mass or less, more preferably 40 parts by mass or less, and still more preferably 30 with respect to 100 parts by mass of the resin constituting the resin particles (A), from the viewpoint of chargeability of the toner. It is below mass parts. Further, from the viewpoint of the cohesiveness of the resin particles, it is preferably 1 part by mass or more, more preferably 3 parts by mass or more, and further preferably 5 parts by mass or more with respect to 100 parts by mass of the resin constituting the resin particles (A). is there. Considering the above points, the amount of monovalent salt used is preferably 1 to 50 parts by mass, more preferably 3 to 40 parts by mass, with respect to 100 parts by mass of the resin constituting the resin particles (A). More preferably, it is 5-30 mass parts.

  As an aggregating method, an aggregating agent is preferably added dropwise as an aqueous solution to a container containing a mixed dispersion. The flocculant may be added at one time, or may be added intermittently or continuously. However, it is preferable to perform sufficient stirring at the time of addition and after completion of the addition. From the viewpoint of controlling aggregation and shortening the toner production time, the dropping time of the aggregating agent is preferably 1 to 120 minutes. Moreover, 0-50 degreeC is preferable from a viewpoint of aggregation control.

  The volume median particle size of the obtained agglomerated particles (1) is preferably 1 to 10 μm, more preferably 2 from the viewpoint of reducing the particle size and reducing the amount of scattering of the resulting toner in a printing machine such as a printer. It is -9 micrometers, More preferably, it is 3-6 micrometers. Further, the CV value is preferably 30% or less, more preferably 28% or less, still more preferably 25% or less, and 5% or more is preferable from the viewpoint of productivity.

<Step 2-2>
Step 2-2 is a step of obtaining aggregated particles (2) by adding resin particles (B) containing amorphous polyester (b) to the aggregated particles (1) obtained in Step 2-1. is there.
In this step, a dispersion of resin particles (B) containing amorphous polyester (b) is added to the dispersion of aggregated particles (1) obtained in step 2-1, and aggregated particles (1 It is preferable that the resin particles (B) are further adhered to the particles to obtain aggregated particles (2).

Before adding the dispersion of resin particles (B) to the dispersion of aggregated particles (1), an aqueous medium may be added to the dispersion of aggregated particles (1) to dilute, or the aqueous medium should be added. Is preferred. By adding the aqueous medium, the resin particles (B) can be more uniformly attached to the aggregated particles (1).
When the resin particle (B) dispersion is added to the dispersion of aggregated particles (1), the aggregating agent may be used to efficiently attach the resin particles (B) to the aggregated particles (1).
As a preferable addition method when the resin particle (B) dispersion is added to the dispersion of the aggregated particles (1), a method of simultaneously adding the aggregating agent and the resin particle (B) dispersion, a flocculant and the resin particles ( B) A method of alternately adding the dispersion liquid and a method of adding the resin particle (B) dispersion liquid while gradually raising the temperature of the dispersion liquid of the aggregated particles (1). By doing in this way, the cohesiveness fall of the aggregated particle (1) and the resin particle (B) by the coagulant | flocculant density | concentration fall can be prevented. From the viewpoint of toner productivity and manufacturing simplicity, it is preferable to add the resin particle (B) dispersion while gradually increasing the temperature of the dispersion of the aggregated particles (1).

  The temperature in the system in this step is 5 ° C. or more lower than the melting point of the crystalline polyester (a1) contained in the resin particles (A) from the viewpoint of low-temperature fixability and high-temperature offset resistance of the toner. It is preferably 3 ° C. or more lower than the glass transition point of b), more preferably 5 ° C. or more. When the aggregated particles (2) are produced within the temperature range, the resulting toner has good low-temperature fixability and high-temperature offset resistance. The reason for this is not clear, but because the agglomerated particles (2) are not fused together, the generation of coarse particles is suppressed, and the crystallinity of the crystalline polyester (a1) can be maintained. Conceivable.

  The addition amount of the resin particles (B) is such that the mass ratio between the resin particles (B) and the resin particles (A) (resin particles (B) / resin particles (A )) Is preferably 0.2 to 1.5, more preferably 0.2 to 1.0, and still more preferably 0.25 to 0.75.

  The resin particle (B) dispersion may be added continuously over a certain period of time, may be added at a time, or may be added in a plurality of divided portions. It is preferable to add them continuously or in several divided portions. By adding as described above, the resin particles (B) are likely to selectively adhere to the aggregated particles (1). Among these, it is preferable to add continuously over a certain time from the viewpoint of promoting selective adhesion and the efficiency of production. The time for continuous addition is preferably 1 to 10 hours, and more preferably 3 to 8 hours, from the viewpoint of obtaining uniform aggregated particles (2) and from the viewpoint of shortening the production time.

The volume median particle size of the aggregated particles (2) obtained in step 2-2 is preferably 1 to 10 μm, more preferably 2 to 10 μm, from the viewpoint of obtaining a toner capable of obtaining a high-quality image. -9 μm is more preferable, and 4-6 μm is more preferable.
The pH of the aggregated particles (2) obtained in step 2-2 is preferably 5.5 to 7.5, more preferably 6.0 to 7.0, and even more preferably 6.0 to 6.5. .

<Step 3>
Step 3 is a step of coalescing the aggregated particles obtained in step 2 to obtain coalesced particles. When step 2 includes steps 2-1 and 2-2, core-shell particles are formed by uniting the aggregated particles (2) obtained in step 2-2.

In the case where Step 2 includes Steps 2-1 and 2-2, from the viewpoint of promoting fusion and improving toner productivity, in this step, preferably the glass transition point of the amorphous polyester (b) or higher. More preferably, it is held at a temperature of 5 ° C. higher than the glass transition point, and more preferably at a temperature of 10 ° C. higher than the glass transition point. From the viewpoint of maintaining the core-shell state of the toner and preventing the release agent from being released, in this step, the temperature is preferably 30 ° C. or higher, more preferably 25 ° C. higher than the glass transition point of the amorphous polyester (b). Hereinafter, it is more preferably maintained at a temperature not higher than 20 ° C.
In this step, from the viewpoint of promoting the fusion of particles, the temperature is preferably 65 to 90 ° C, more preferably 70 to 90 ° C, and still more preferably 70 to 85 ° C.
The holding time in this step is preferably 30 seconds to 24 hours, more preferably 1 minute to 10 hours, and still more preferably from the viewpoint of improving particle fusing property, heat resistant storage stability of toner, chargeability and toner productivity. Is 6 minutes to 1 hour.

From the viewpoint of obtaining a high-quality image, the volume-median particle size of the coalesced particles obtained in this step is preferably 2 to 10 μm, more preferably 2 to 8 μm, more preferably 2 to 7 μm, and still more preferably 3 to 3 μm. It is 8 μm, more preferably 4 to 6 μm.
In addition, it is preferable that the average particle diameter of the fused coalesced particles obtained in this step is equal to or less than the average particle diameter of the aggregated particles. That is, in this step, it is preferable that the coalesced particles are not aggregated or fused.
The mass ratio (core / shell ratio) of the resin in the core and the resin in the shell of the core-shell particles obtained in this step is preferably 90/10 to 55/45, more preferably 90/10 to 10. The amount is preferably 60/40, more preferably 80/20 to 65/35.

[Post-processing process]
In the present invention, a post-treatment step may be performed after step 3, and it is preferable to obtain toner particles by isolating coalesced particles.
Since the coalesced particles obtained in step 3 are present in the aqueous medium, it is preferable to first perform solid-liquid separation.
It is preferable to perform washing after the solid-liquid separation.
Next, it is preferable to perform drying. The water content after drying is preferably adjusted to 1.5% by mass or less, more preferably 1.0% by mass or less, from the viewpoint of suppressing toner scattering and improving the chargeability.

[Electrophotographic toner]
(toner)
The toner particles obtained by drying or the like can be used as they are as the toner of the present invention, but it is preferable to use toner particles whose surface has been treated as described below as the toner for electrophotography.
The softening point of the obtained toner is preferably 60 to 140 ° C., more preferably 60 to 130 ° C., and still more preferably 60 to 120 ° C. from the viewpoint of improving the low-temperature fixability of the toner. The glass transition point is preferably 20 to 70 ° C., more preferably 25 to 60 ° C., from the viewpoint of improving low-temperature fixability, durability and heat-resistant storage stability.
The volume-median particle size of the toner is preferably 1 to 10 μm, more preferably 2 to 8 μm, still more preferably 3 to 7 μm, and still more preferably 4 from the viewpoint of obtaining a high-quality printed matter with the toner and improving productivity. ~ 6 μm.
The CV value of the toner is preferably 30% or less, more preferably 27% or less, and even more preferably 25% or less from the viewpoint of improving the productivity by obtaining a high-quality printed matter. % Or more is preferable.
The degree of circularity of the toner is preferably 0.950 to 0.995, more preferably 0.955 to 0.990, and more preferably 0.960 to 0.985 from the viewpoint of suppressing toner scattering and improving cleaning properties. Further preferred.
The BET specific surface area of the toner is preferably 1.0 to 2.5, more preferably 1.1 to 1.8, and more preferably 1.2 to 1.5 from the viewpoint of suppressing toner scattering and improving heat-resistant storage stability. Is more preferable.

(External additive)
In the electrophotographic toner of the present invention, the toner particles can be used as the toner as they are, but it is preferable to use a toner obtained by adding a fluidizing agent or the like to the toner particle surface as an external additive.
Examples of the external additive include hydrophobic silica, titanium oxide fine particles, alumina fine particles, cerium oxide fine particles, inorganic fine particles such as carbon black, and polymer fine particles such as polycarbonate, polymethyl methacrylate, and silicone resin. Among these, hydrophobic Silica is preferred.
When the surface treatment of toner particles is performed using an external additive, the amount of the external additive added is preferably 1 to 5 parts by mass, more preferably 2 to 4 parts by mass with respect to 100 parts by mass of the toner particles. .

  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 of polyester, resin particles, toner, etc. was measured and evaluated by the following method.

[Acid value of polyester]
It measured according to JIS K0070. However, the measurement solvent was chloroform.

[Polyester softening point, crystallinity index, melting point and glass transition point]
(1) Softening point Using a flow tester (manufactured by Shimadzu Corporation, trade name: CFT-500D), a load of 1.96 MPa was applied by a plunger while heating a 1 g sample at a heating rate of 6 ° C / min. And extruded from a nozzle with a diameter of 1 mm and a length of 1 mm. A flow tester drop amount of the flow tester was plotted against the temperature, and the temperature at which half of the sample flowed out was defined as the softening point.

(2) Crystallinity index Using a differential scanning calorimeter (trade name: Q100, manufactured by TA Instruments Japan Co., Ltd.), it was cooled from room temperature (20 ° C.) to 0 ° C. at a cooling rate of 10 ° C./min. The sample was allowed to stand still for 1 minute, and then heated to 180 ° C. at a heating rate of 10 ° C./min. Of the observed peaks, the peak temperature with the maximum peak area is defined as the endothermic maximum peak temperature (1), and the crystallinity by (softening point (° C)) / (maximum endothermic peak temperature (1) (° C)). The index was determined.

(3) Melting point and glass transition point The temperature was raised to 200 ° C. using a differential scanning calorimeter (trade name: Q100, manufactured by TA Instruments Japan Co., Ltd.), and the temperature was lowered at a rate of 10 ° C./min. The sample cooled to 0 ° C. was subsequently measured at a heating rate of 10 ° C./min. Among the observed endothermic peaks, the temperature of the peak having the maximum peak area was defined as the maximum endothermic temperature (2). In the case of crystalline polyester, the peak temperature was taken as the melting point. In the case of an amorphous polyester, when an endothermic peak is observed, the temperature of the peak is measured. The glass transition point was defined as the temperature at the intersection with the base line extension line on the high temperature side.

[Volume Median Particle Size (D ₅₀ ) and Particle Size Distribution of Aggregated Particles]
The volume median particle size of the aggregated particles was measured as follows.
Measuring instrument: Coulter Multisizer III (trade name, manufactured by Beckman Coulter)
・ Aperture diameter: 50μm
・ Analysis software: Multisizer III version 3.51 (trade name, manufactured by Beckman Coulter)
Electrolyte: Isoton II (trade name, manufactured by Beckman Coulter)
Measurement conditions: 30,000 particles are measured after adjusting the particle size of 30,000 particles to a concentration that can be measured in 20 seconds by adding a sample dispersion containing aggregated particles to 100 mL of the electrolyte. The volume-median particle size (D ₅₀ ) was determined from the particle size distribution.
Further, the CV value (%) as a particle size distribution was calculated according to the following formula.
CV value (%) = (standard deviation of particle size distribution / volume median particle size (D ₅₀ )) × 100

[Volume Median Particle Size (D ₅₀ ) of Toner (Particles)]
The volume median particle size of the toner (particles) was measured as follows.
The measuring instrument, aperture diameter, analysis software, and electrolyte solution were the same as the volume median particle diameter of the aggregated particles.
Dispersion: Polyoxyethylene lauryl ether (manufactured by Kao Corporation, trade name: Emulgen 109P, HLB: 13.6) was dissolved in the electrolytic solution to obtain a dispersion having a concentration of 5% by mass.
Dispersion condition: 10 mg of a toner measurement sample is added to 5 mL of the dispersion, and dispersed for 1 minute with an ultrasonic disperser. Then, 25 mL of electrolyte is added, and further dispersed for 1 minute with an ultrasonic disperser. A sample dispersion was prepared.
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 and the particle size distribution is determined. The volume median particle size (D ₅₀ ) was determined.

[Volume Median Particle Size (D ₅₀ ) and Particle Size Distribution of Resin Particles, Release Agent Particles]
(1) Measuring device: Laser diffraction particle size measuring machine (Horiba, Ltd., trade name: LA-920)
(2) Measurement conditions: Distilled water was added to the measurement cell, and the volume-median particle size (D ₅₀ ) was measured at a concentration at which the absorbance was 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) × 100

[Solid content concentration of resin particle dispersion and release agent particle dispersion]
Using an infrared moisture meter (trade name: FD-230, manufactured by Ketto Scientific Laboratory Co., Ltd.), a measurement sample 5 g was dried at a temperature of 150 ° C. and a measurement mode 96 (monitoring time 2.5 minutes / variation width 0.05%). ) To measure the moisture percentage. The solid content concentration was calculated according to the following formula.
Solid content concentration (% by mass) = 100-M
M: moisture (%) = [(W−W ₀ ) / W] × 100
W: Sample mass before measurement (initial sample mass)
W ₀ : Mass of sample after measurement (absolute dry mass)

[Toner circularity]
As a toner dispersion, 50 mg of toner is added to 5 ml of a 5% by weight polyoxyethylene lauryl ether (Emulgen 109P) aqueous solution, dispersed for 1 minute with an ultrasonic disperser, 20 ml of distilled water is added, and ultrasonic waves are further added. Prepared by dispersing for 1 minute in a disperser.
Measuring device: Flow type particle image analyzer (manufactured by Sysmex Corporation, trade name: FPIA-3000)
Measurement mode: HPF measurement mode

[Toner fixing area: low temperature fixing temperature to high temperature offset temperature]
Using a commercially available printer (trade name: Microline 5400, manufactured by Fuji Xerox Co., Ltd., J paper A4 size), the toner adhesion amount on the paper is 0.42 to 0.48 mg. A solid image of / cm ² was output without being fixed at a length of 50 mm, leaving a margin of 5 mm from the top edge of the A4 paper.
Next, the same printer with a variable temperature fixing device was prepared, the fixing device temperature was set to 90 ° C., and fixing was performed at a speed of 1.2 seconds per sheet in the A4 longitudinal direction to obtain a printed matter.
In the same manner, the temperature of the fixing device was increased by 5 ° C., and the fixing was performed to obtain a printed matter.
A 500 g weight is applied to the margin at the top of the printed image, after lightly pasting a piece of mending tape (product name: Scotch mending tape 810, width 18 mm) cut to a length of 50 mm. It was loaded and pressed once and again at a speed of 10 mm / sec. Thereafter, the affixed tape was peeled off from the lower end side at a peeling angle of 180 degrees and a speed of 10 mm / second to obtain a printed matter after the tape was peeled off. 30 sheets of high quality paper (Oki Data Co., Ltd., Excellent White Paper A4 size) is placed under the printed material before and after the tape is applied, and the reflected image density of the fixed image portion before and after the tape is applied to each printed material. , Using a colorimeter (GretagMacbeth, trade name: SpectroEye, light condition; standard light source D ₅₀ , observation field of view 2 °, density standard DINNB, absolute white standard), and calculating the fixing rate using the following formula did.
Fixing rate = (reflected image density after peeling tape / reflected image density before applying tape) × 100
The temperature at which the fixing rate was 90% or more was defined as the minimum fixing temperature. The lower the minimum fixing temperature, the better the low-temperature fixing property.
Further, the fixing temperature was raised, and the fixing region at a high temperature was determined in the same manner as described above. The temperature at which the fixing rate was less than 90% was defined as the high temperature offset temperature. The higher the high temperature offset temperature, the higher the fixing region at a high temperature.

[Residual rate of release agent in toner]
It is converted from the endothermic peak endothermic peak (measured value) derived from the release agent obtained by measuring the obtained electrophotographic toner with a differential scanning calorimeter and the endothermic amount obtained by measuring the release agent alone. The ratio of the endothermic peak to the endothermic amount (converted value) was determined by the following formula.
Residual rate of release agent (%) = [(Endothermic amount derived from release agent in toner (actual value) / (Release agent in toner converted from endothermic amount obtained by measuring release agent alone) Derived endothermic amount (converted value)]] × 100
(Endothermic amount derived from the release agent in the toner (unit weight) converted from the endotherm obtained by measuring the release agent alone)
Using a differential scanning calorimeter (trade name: Q-100, manufactured by TA Instruments Japan Co., Ltd.), the release agent used for the toner was heated up to 150 ° C. at 5 ° C./min, and released. The endothermic amount of the agent was measured.
The value obtained by multiplying the amount of heat absorbed by the release agent by the theoretical weight ratio of the release agent in the core-shell particles (excluding surfactants and external additives) was measured by the release agent alone. The heat absorption amount (converted value) derived from the release agent in the toner converted from the heat amount was used.
(Endothermic amount derived from release agent in toner (unit weight) (actual value))
The obtained toner was heated to 200 ° C. at 5 ° C./min using the above differential scanning calorimeter, then rapidly cooled to 100 ° C./min to 0 ° C., and then from 0 ° C. to 150 ° C. at 5 ° C. / The temperature was increased in minutes, and the endothermic amount of the release agent was measured. This value was taken as an actual measurement value.

[Filterability of coalesced particles]
Weighed so that the coalesced particles in the coalesced particle dispersion was 5.2 g, spread a qualitative filter paper (Advantech, type No. 2) on Nutsche with a diameter of 70 cm, filtered the coalesced particle dispersion, The time required for filtering 240 mL of ion exchange water is measured. The short time indicates that the process of cleaning the coalesced particles can be shortened. When the release agent is leaking from the coalesced particles, the filter paper is clogged and the filtration time becomes long.

[Release status of release agent in the coalescence process]
Collect 5 g of the combined particle dispersion in a centrifuge tube, and precipitate the combined particles by centrifuging at 4000 rpm for 1 minute using a centrifuge (manufactured by HSIANGTAI, trade name: CN-2060). The state of the supernatant was visually observed.
When the supernatant is colorless and transparent, it indicates that the release agent is not liberated. When the supernatant is cloudy, it indicates that the release agent is liberated, and the higher the degree of cloudiness, the greater the release agent release.

[Production of polyester]
Production example CP1
(Production of crystalline polyester (A))
The inside of a four-necked flask equipped with a nitrogen introducing tube, a dehydrating tube, a stirrer, and a thermocouple was purged with nitrogen, and 5050 g of 1,12-dodecanediol as an alcohol component and 2950 g of succinic acid as an acid component were added. While stirring, the temperature was raised to 135 ° C., maintained at 135 ° C. for 3 hours, and then heated from 135 ° C. to 200 ° C. over 10 hours. Thereafter, 16 g of di (2-ethylhexanoic acid) tin was added, and the mixture was further maintained at 200 ° C. for 1 hour. Then, the pressure in the flask was lowered and maintained at 8.3 kPa for 1 hour. Obtained. The softening point was 87 ° C, the melting point was 79 ° C, and the crystallinity index was 1.1. The acid value was 8.2 mgKOH / g.

Production example AP1
(Production of amorphous polyester (B))
The inside of a four-necked flask equipped with a nitrogen introduction tube, a dehydration tube, a stirrer, and a thermocouple was replaced with nitrogen, and 1750 g of polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, A nitrogen atmosphere containing 1625 g of polyoxyethylene (2.0) -2,2-bis (4-hydroxyphenyl) propane, 1145 g of terephthalic acid, 161 g of dodecenyl succinic anhydride, 480 g of trimellitic anhydride, and 10 g of dibutyltin oxide Under stirring, the temperature was raised to 220 ° C. and maintained at 220 ° C. for 5 hours. After confirming that the softening point measured according to ASTM D36-86 reached 120 ° C., the temperature was lowered to stop the reaction. Amorphous polyester (B) was obtained. The glass transition point was 64 ° C., the softening point was 122 ° C., and the crystallinity index was 1.6. The acid value was 21.0 mgKOH / g.

Production example AP2
(Production of amorphous polyester (C))
The inside of a four-necked flask equipped with a nitrogen introduction tube, a dehydration tube, a stirrer, and a thermocouple was replaced with nitrogen, and 3374 g of polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, Polyoxyethylene (2.0) -2,2-bis (4-hydroxyphenyl) propane (33 g), terephthalic acid (672 g) and dibutyltin oxide (10 g) were added, and the temperature was raised to 230 ° C. with stirring in a nitrogen atmosphere. After maintaining the time, the pressure in the flask was further reduced and maintained at 8.3 kPa for 1 hour. Then, after cooling to 210 ° C. and returning to atmospheric pressure, 696 g of fumaric acid and 0.49 g of tert-butylcatechol were added and maintained at a temperature of 210 ° C. for 5 hours. The amorphous polyester (C) was obtained by maintaining at 3 kPa for 4 hours. The glass transition point was 65 ° C., the softening point was 107 ° C., and the crystallinity index was 1.5. The acid value was 24.4 mgKOH / g.

Production example AP3
(Production of amorphous polyester (D))
The inside of the four-necked flask equipped with a nitrogen introduction tube, a dehydration tube, a stirrer, and a thermocouple was replaced with nitrogen, and 3004 g of polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, 996 g of fumaric acid, 2 g of tert-butylcatechol and 8 g of dibutyltin oxide were added, heated to 210 ° C. over 5 hours with stirring in a nitrogen atmosphere, held at 210 ° C. for 2 hours, and then at 8.3 KPa. The reaction was continued until the following softening point was reached to obtain amorphous polyester (D). The glass transition point was 57 ° C., the softening point was 101 ° C., and the crystallinity index was 1.5. The acid value was 22.4 mgKOH / g.

Production example AP4
(Production of amorphous polyester (E))
The inside of a four-necked flask equipped with a nitrogen introduction tube, a dehydration tube, a stirrer, and a thermocouple was replaced with nitrogen, and 3528 g of polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, Polyoxyethylene (2.0) -2,2-bis (4-hydroxyphenyl) propane (1404 g), terephthalic acid (1248 g), dodecenyl succinic anhydride (1541 g), and dibutyltin oxide (20 g) were added. After raising the temperature to ℃ and maintaining at 230 ℃ for 6 hours, the pressure in the flask was further reduced and maintained at 8.3 kPa for 1 hour. Then, after cooling to 215 ° C. and returning to atmospheric pressure, 300 g of trimellitic anhydride was added and maintained at 215 ° C. for 1 hour, then the pressure in the flask was further lowered and maintained at 8.3 kPa for 3 hours. Thus, an amorphous polyester (E) was obtained. The glass transition point was 57 ° C. and the softening point was 118 ° C. The acid value was 19.1 mgKOH / g.

Production example MB1
(Manufacture of master batch (F) containing copper phthalocyanine pigment)
70 parts by mass of fine powder of amorphous polyester (D) obtained in Production Example AP3 and a slurry pigment of copper phthalocyanine (manufactured by Dainichi Seika Kogyo Co., Ltd., trade name: ECB-301, solid content 46.2% by mass) Was placed in a Henschel mixer so that the pigment content was 30 parts by mass, mixed for 5 minutes and wetted. Next, this mixture was charged into a kneader mixer and gradually heated. The resin was melted at approximately 90 to 110 ° C. and kneaded in a state where water was mixed, and kneading was continued at 90 to 110 ° C. for 20 minutes while water was evaporated.
Further, the kneading was continued at 120 ° C. to evaporate the remaining water, followed by dehydration drying. Further, kneading was continued at 120 to 130 ° C. for 10 minutes. After cooling, the mixture was further kneaded with a heated three roll, cooled and coarsely crushed to obtain a crushed product (master batch (F)) of a high-concentration colored composition containing a blue pigment at a concentration of 30% by mass. When this was placed on a slide glass, heated and melted, and observed with a microscope, all pigment particles were finely dispersed, and no coarse particles were observed.

[Production of dispersion of resin particles]
Production Example A1
(Production of dispersion of resin particles (A-1))
In a flask equipped with a stirrer, 90 g of crystalline polyester (A), 285 g of amorphous polyester (C), 120 g of amorphous polyester (E), 150 g of master batch (F) containing copper phthalocyanine pigment, polyoxyethylene alkyl 8.5 g of ether (nonionic surfactant, trade name: Emulgen 150, manufactured by Kao Corporation), 15% by weight aqueous sodium dodecylbenzenesulfonate (anionic surfactant, trade name: Neoperex G-15, Kao) 80 g of 5% by mass potassium hydroxide aqueous solution was added, and the mixture was heated to 95 ° C. and melted while stirring, and mixed at 95 ° C. for 2 hours to obtain a resin mixture.
Next, 1113 g of deionized water was added dropwise at a rate of 6 g / min while stirring to obtain an emulsion. Next, the obtained emulsion was cooled to 25 ° C., and a resin particle dispersion was obtained through a 200-mesh (mesh 105 μm) wire mesh.
Furthermore, the obtained resin particle dispersion and an oxazoline group-containing acrylic polymer aqueous solution (manufactured by Nippon Shokubai Co., Ltd., trade name: Epocross WS-700, nonvolatile content 25% by mass, acrylic main chain, oxazoline in oxazoline group-containing polymer Group content: 4.55 mmol / g, number average molecular weight: 20,000) and 22.7 g were mixed and kept at 95 ° C. for 1 hour with stirring. Next, the obtained emulsion is cooled to 25 ° C., passed through a 200-mesh wire mesh, deionized water is added to adjust the solid content to 30% by mass, and a dispersion of resin particles (A-1) Got. The volume median particle size of the resin particles (A-1) was 0.143 μm, and the CV value was 29.8%.

Production Example A2
(Production of dispersion of resin particles (A-2))
In a flask having an internal volume of 5 liters, 210 g of amorphous polyester (B), 390 g of amorphous polyester (C), polyoxyethylene alkyl ether (nonionic surfactant, trade name: Emulgen 430, manufactured by Kao Corporation) 6 g, 40 g of 15% by mass aqueous sodium dodecylbenzenesulfonate (Neopelex G-15) and 278 g of 5% by mass potassium hydroxide are added, and the mixture is heated to 95 ° C. with stirring and melted, and mixed at 95 ° C. for 2 hours. Thus, a resin mixture was obtained.
Next, 1135 g of deionized water was added dropwise at a rate of 6 g / min while stirring to obtain an emulsion. Next, the obtained emulsion was cooled to 25 ° C., passed through a 200-mesh wire mesh, deionized water was added to adjust the solid content to 16.5% by mass, and the resin particles (A-2) A dispersion was obtained. The volume median particle size of the resin particles (A-2) was 0.158 μm, the CV value was 24.0%, and the glass transition point was 60 ° C.

Production Example A3
(Production of dispersion of resin particles (A-3))
In a flask having an internal volume of 5 liters, amorphous polyester (B) 210 g, amorphous polyester (C) 285 g, copper phthalocyanine pigment-containing masterbatch (F) 150 g, polyoxyethylene alkyl ether (nonionic surfactant, Product name: Emulgen 430, manufactured by Kao Corporation) 6g, 15% by weight sodium dodecylbenzenesulfonate aqueous solution (Neopelex G-15) 40g, and 5% by weight potassium hydroxide 274g were added and heated to 95 ° C while stirring. The mixture was warmed and melted and mixed at 95 ° C. for 2 hours to obtain a resin mixture.
Next, 1143 g of deionized water was added dropwise at a rate of 6 g / min while stirring to obtain an emulsion. Next, the obtained emulsion was cooled to 25 ° C. and passed through a 200-mesh wire mesh to obtain a resin particle dispersion.
Further, the obtained resin particle dispersion was mixed with 22.6 g of the above oxazoline group-containing acrylic polymer aqueous solution (trade name: Epocross WS-700, manufactured by Nippon Shokubai Co., Ltd.) and held at 95 ° C. for 1 hour with stirring. did. Next, the obtained emulsion is cooled to 25 ° C., passed through a 200-mesh wire mesh, deionized water is added to adjust the solid content to 30% by mass, and a dispersion of resin particles (A-3) Got. The volume median particle size of the resin particles (A-3) was 0.157 μm, and the CV value was 26.3%.

[Production of dispersion of release agent particles]
Production Example W1
(Manufacture of dispersion liquid of release agent particles (W-1))
In a 500 ml beaker, 250 g of deionized water, 27 g of carnauba wax (manufactured by Hiroyuki Kato, trade name: carnauba wax No. 1, melting point 83 ° C., acid value 5 mg KOH / g) and paraffin wax (Nippon Seiki) Product name: HNP-9, melting point 75 ° C. (63 g) was added, and the wax was melt mixed while maintaining the temperature at 95 ° C. Then, while maintaining the temperature at 95 ° C., 3.04 g of the above oxazoline group-containing acrylic polymer aqueous solution (product name: Epocross WS-700, manufactured by Nippon Shokubai Co., Ltd.) was added, stirred for 15 minutes with a homomixer, 1.8 g sugar stearate ester (Mitsubishi Chemical Foods Co., Ltd., trade name: Ryoto Sugar Ester S1170) and sucrose stearate ester (Mitsubishi Chemical Foods Co., Ltd., trade name: Ryoto Sugar Ester S570) 1 0.8 g was added, and the mixture was further stirred for 15 minutes with a homomixer to obtain a preliminary emulsion. While maintaining this preliminary emulsified liquid at 80 to 95 ° C., it was treated three times with a nanomizer (manufactured by Yoshida Kikai Kogyo Co., Ltd., trade name: NM2-L200-D08) at a pressure of 100 MPa, and then cooled to room temperature. Exchange water was added to adjust the release agent solid content to 20% by mass to obtain a dispersion of release agent particles (W-1). The volume median particle size (D ₅₀ ) of the release agent particles (W-1) in the dispersion was 241 nm, and the CV value was 28.3%.

Production Example W2
(Manufacture of dispersion liquid of release agent particles (W-2))
Dispersion liquid of release agent particles (W-2) in the same manner as in Production Example W1, except that the amount of carnauba wax and paraffin wax used in Production Example W1 was changed to 9 g of Carnauba wax and 81 g of paraffin wax. Got. The volume median particle size (D ₅₀ ) of the release agent particles (W-2) in the dispersion was 240 nm, and the CV value was 28.2%.

Production Example W3
(Production of dispersion of release agent particles (W-3))
In a 500 ml beaker, 250 g of deionized water, 27 g of Carnauba wax (manufactured by Hiroyuki Kato, product name: Carnauba wax 1, melting point 83 ° C.) and paraffin wax (manufactured by Nippon Seiki Co., Ltd., product) Name: HNP-9, melting point 75 ° C.) 63 g was added, and the wax was melt mixed while maintaining the temperature at 95 ° C. Thereafter, while maintaining the temperature at 95 ° C., 1.8 g of sucrose stearate (manufactured by Mitsubishi Chemical Foods Co., Ltd., trade name: Ryoto Sugar Ester S1170) and sucrose stearate (Mitsubishi Chemical Foods Co., Ltd.) (Product name: Ryoto Sugar Ester S570) 1.8 g was added and stirred with a homomixer for 15 minutes to obtain a preliminary emulsion. While maintaining this preliminary emulsified liquid at 80 to 95 ° C., it was treated three times with a nanomizer (manufactured by Yoshida Kikai Kogyo Co., Ltd., trade name: NM2-L200-D08) at a pressure of 100 MPa, and then cooled to room temperature. Exchange water was added to adjust the release agent solid content to 20% by mass to obtain a dispersion of release agent particles (W-3). The volume median particle size (D ₅₀ ) of the release agent particles (W-3) in the dispersion was 223 nm, and the CV value was 30.0%.

Production Example W4
(Production of dispersion liquid of release agent particles (W-4))
In a 500 ml beaker, 250 g of deionized water, 27 g of Carnauba wax (manufactured by Hiroyuki Kato, product name: Carnauba wax 1, melting point 83 ° C.) and paraffin wax (manufactured by Nippon Seiki Co., Ltd., product) Name: HNP-9, melting point 75 ° C.) 63 g was added, and the wax was melt mixed while maintaining the temperature at 95 ° C. Thereafter, while maintaining the temperature at 95 ° C., 1.8 g of sucrose stearate (manufactured by Mitsubishi Chemical Foods Co., Ltd., trade name: Ryoto Sugar Ester S1170) and sucrose stearate (Mitsubishi Chemical Foods Co., Ltd.) Product, product name: Ryoto Sugar Ester S570) was added, and after stirring for 15 minutes with a homomixer, the oxazoline group-containing acrylic polymer aqueous solution (manufactured by Nippon Shokubai Co., Ltd., product name: Epocross WS-700) 3. 04 g was added, and further stirred with a homomixer for 15 minutes to obtain a preliminary emulsion. While maintaining this preliminary emulsified liquid at 80 to 95 ° C., it was treated three times with a nanomizer (manufactured by Yoshida Kikai Kogyo Co., Ltd., trade name: NM2-L200-D08) at a pressure of 100 MPa, and then cooled to room temperature. Exchange water was added to adjust the release agent solid content to 20% by mass to obtain a dispersion of release agent particles (W-4). The volume median particle size (D ₅₀ ) of the release agent particles (W-4) in the dispersion was 177 nm, and the CV value was 34.0%.

Production Example W5
(Manufacture of dispersion liquid of release agent particles (W-5))
In a 500 ml beaker, 90 g of Carnauba wax (trade name: Carnauba Wax No. 1, melting point 83 ° C.) was added to 250 g of deionized water, and the wax was maintained while maintaining the temperature at 95 ° C. Were melt mixed. Thereafter, while maintaining the temperature at 95 ° C., 1.8 g of sucrose stearate (manufactured by Mitsubishi Chemical Foods Co., Ltd., trade name: Ryoto Sugar Ester S1170) and sucrose stearate (Mitsubishi Chemical Foods Co., Ltd.) Product, product name: Ryoto Sugar Ester S570) was added, and after stirring for 15 minutes with a homomixer, the oxazoline group-containing acrylic polymer aqueous solution (manufactured by Nippon Shokubai Co., Ltd., product name: Epocross WS-700) 3. 04 g was added, and further stirred with a homomixer for 15 minutes to obtain a preliminary emulsion. While maintaining this preliminary emulsified liquid at 80 to 95 ° C., it was treated three times with a nanomizer (manufactured by Yoshida Kikai Kogyo Co., Ltd., trade name: NM2-L200-D08) at a pressure of 100 MPa, and then cooled to room temperature. Exchange water was added to adjust the release agent solid content to 20% by mass to obtain a dispersion of release agent particles (W-5). The volume median particle size (D ₅₀ ) of the release agent particles (W-5) in the dispersion was 210 nm, and the CV value was 29.0%.

[Production of toner]
Example 1
(Manufacture of toner 1)
In a four-necked flask with an internal volume of 2 liters equipped with a dehydrating tube, a stirrer, and a thermocouple, 250 g of a dispersion of resin particles (A-1), 41 g of deionized water, and release agent particles (W-1) 35 g of the dispersion was mixed at a temperature of 25 ° C. Next, while stirring the mixture, an aqueous solution in which 21 g of ammonium sulfate was dissolved in 216 g of deionized water was added dropwise at 25 ° C. over 10 minutes, and then the temperature was raised to 60 ° C. so that the volume median particle size of the aggregated particles was 4 It was kept at 60 ° C. until it became 6 μm to obtain a dispersion of aggregated particles (1).
While increasing the temperature of the dispersion liquid of the aggregated particles (1) at a rate of 0.8 ° C./hour, 126 g of the dispersion liquid of the resin particles (A-2) was dropped at a rate of 0.7 ml / min. A dispersion of 2) was obtained. Moreover, the temperature of the dispersion liquid after completion | finish of dripping was 58 degreeC.
An aqueous solution obtained by mixing 15 g of an anionic surfactant (trade name: EMAL (registered trademark) E27C, effective concentration: 27% by mass), 1183 g of deionized water is added to the dispersion of the agglomerated particles (2). did. The temperature was raised to 80 ° C. and held at 80 ° C. for 5 minutes to fuse the particles to obtain core-shell particles.
The obtained core-shell particle dispersion was cooled to 30 ° C., the solid content of the dispersion was separated by suction filtration, washed with deionized water, and dried at 33 ° C. to obtain toner particles. 100 parts by mass of the toner particles, 2.5 parts by mass of hydrophobic silica (manufactured by Nippon Aerosil Co., Ltd., trade name: RY50, average particle size; 0.04 μm), and hydrophobic silica (manufactured by Cabot Corporation, trade name: Cabo Seal) TS720, average particle size: 0.012 μm) 1.0 part by mass was put in a Henschel mixer, stirred, and passed through a 150 mesh sieve to obtain toner 1. Table 4 shows the physical properties and evaluation of the toner.

Example 2
(Manufacture of toner 2)
Toner in the same manner as in Example 1 except that the dispersion of release agent particles (W-1) in Example 1 was changed to the dispersion of release agent particles (W-2) shown in Table 4. 2 was obtained. Table 4 shows the physical properties and evaluation of the toner.

Comparative Examples 1, 2, and 4
(Production of toners 3, 4 and 6)
In the same manner as in Example 1 except that the dispersion of the release agent particles (W-1) in Example 1 was changed to the dispersion of release agent particles shown in Table 4 , toners 3, 4 and 6 Got. Table 4 shows the physical properties and evaluation of the toner.

Comparative Example 3
(Manufacture of toner 5)
In Example 1, 35 g of the release agent particle (W-1) dispersion 35 g, 35 g of the release agent particle (W-3) dispersion and the oxazoline group-containing acrylic polymer aqueous solution (product of Nippon Shokubai Co., Ltd., product) Name: Epocross WS-700) Toner 5 was obtained in the same manner as in Example 1 except that it was changed to 0.25 g. Table 4 shows the physical properties and evaluation of the toner.

Comparative Example 5
(Manufacture of toner 7)
In Example 1, the dispersion of resin particles (A-1) was changed to a dispersion of resin particles (A-3), and the dispersion of release agent particles (W-1) was changed to release agent particles (W- Toner 7 was obtained in the same manner as in Example 1 except that the dispersion was changed to 5). Table 4 shows the physical properties and evaluation of the toner.

From Table 4, when producing the release agent dispersion, the release agent particles (W-1) or (W-) in which the oxazoline-containing polymer was added to the wax mixture and then the release agent particles were dispersed in water with an emulsifier. In Examples 1 and 2 using the dispersion liquid 2), release of the release agent during the production of the toner can be suppressed, and an electrophotographic toner excellent in low-temperature fixability and high-temperature offset resistance could be produced. .
On the other hand, after emulsifying the wax mixture, in Comparative Example 1 using the dispersion of the release agent particles (W-4) to which the oxazoline-containing polymer was added, the release agent is liberated and the filterability is lowered. At the same time, the survival rate was low.
In Comparative Examples 2 and 5 using the release agent particles (W-5) containing no hydrocarbon wax, release of the release agent at the time of toner production can be suppressed. The releasability could not be exhibited (Comparative Example 2), while the toner containing no crystalline polyester was inferior in low-temperature fixability (Comparative Example 5).
In Comparative Example 3 in which a dispersion of release agent particles (W-3) to which no oxazoline-containing polymer was added during the production of the release agent was used, and the oxazoline-containing polymer was used when the resin particles (A-1) were aggregated, Release of the release agent during production could not be prevented. Similarly, in Comparative Example 4 using a dispersion of release agent particles (W-3) to which no oxazoline-containing polymer was added during the production of the release agent, release of the release agent during toner production could not be prevented. It was.

  As a result, when a hydrocarbon wax (paraffin wax) is used as a release agent, it is possible to use a release agent dispersion in which an oxazoline-containing polymer is added to the release agent and then dispersed with an emulsifier. It was found to be effective in suppressing release of the release agent from the coalesced particles during the treatment.

  The electrophotographic toner obtained by the production method of the present invention can suppress release of the release agent from the coalesced particles at the time of toner production, and has excellent properties such as low-temperature fixability and high-temperature offset resistance. It can be suitably used as an electrophotographic toner used in electrophotographic methods, electrostatic recording methods, electrostatic printing methods and the like. According to the method of the present invention, a toner having such characteristics can be produced efficiently.

Claims (6)

A method for producing an electrophotographic toner comprising the following steps 1 to 3.
Step 1: A wax mixture containing a hydrocarbon wax and an ester wax having a carboxy group and an acid value of 0.5 mgKOH / g or more is mixed with a polymer having an oxazoline group, and then dispersed in an aqueous medium. Step 2: Obtaining an aqueous dispersion of release agent particles Step 2: Mixing an aqueous dispersion of release agent particles obtained in Step 1 with an aqueous dispersion of resin particles containing a resin having a carboxy group. Step of aggregating to obtain aggregated particles Step 3: Step of coalescing the aggregated particles obtained in step 2 to obtain coalesced particles   The method for producing an electrophotographic toner according to claim 1, wherein the ester wax is carnauba wax.   The method for producing an electrophotographic toner according to claim 1, wherein the resin particles containing a resin having a carboxy group include resin particles of crystalline polyester and resin particles of amorphous polyester.   The method for producing an electrophotographic toner according to claim 1, wherein the wax mixture and the polymer having an oxazoline group are mixed at 50 ° C. or higher and 99 ° C. or lower.   The electrophotography according to claim 3 or 4, wherein the crystalline polyester is obtained by polycondensing an alcohol component containing an α, ω-alkanediol having 10 to 12 carbon atoms and an acid component containing an aliphatic dicarboxylic acid. Of manufacturing toner. The mixing ratio of the wax mixture and the polymer having an oxazoline group is 1/20 or more and 5/1 or less as a ratio of the number of carboxy groups of the ester wax to the number of moles of oxazoline groups (carboxy group / oxazoline group). A method for producing an electrophotographic toner according to claim 1.