JP5635379B2 - Method for producing toner for electrophotography - Google Patents

Description

  The present invention relates to a method for producing an electrophotographic toner and an electrophotographic toner obtained thereby.

In the field of electrophotographic toner, with the development of an electrophotographic system, a toner corresponding to high image quality and high speed is required.
In order to meet the demands for higher image quality and higher speed, the toner is also required to have various performances. As a method capable of arbitrarily adjusting the surface property, a toner production method by an emulsion aggregation method has been proposed.

For example, Patent Document 1 discloses an amorphous polyester having 2.0 to 12.0 mol% of a trivalent or higher carboxylic acid in one reaction vessel for the purpose of improving low temperature fixability and hot offset resistance. And a polyester particle dispersion obtained by a production method comprising a step of emulsifying a polyester containing a crystalline polyester in an aqueous medium, or a step of mixing the polyester with an organic solvent and then emulsifying by adding an aqueous medium. And an electrophotographic toner obtained by combining them.
In Patent Document 2, core particles containing at least a binder resin, a colorant, and a release agent are coated for the purpose of achieving both low-temperature fixability, image glossiness, and a long developer life. And 75% by mass or more of the binder resin contained in the core particle is the polyester resin A, and 75% by mass or more of the shell layer is the polyester resin B. In addition, there is disclosed an electrophotographic toner in which the amount of isophthalic acid or dodecenyl succinic acid in the polyester resin B satisfies a specific relationship, and the solubility parameters of the polyester resin A and the polyester resin B satisfy a specific relationship.
Patent Document 3 includes a crystalline polyester resin and a release agent that are present in a certain proportion in the structure in which the crystalline polyester resin and the release agent are in contact with each other for the purpose of improving fixing performance, heat storage property, and the like. A toner, a resin solution in which an amorphous polyester resin and a crystalline polyester resin are dissolved in an organic solvent, a neutralizer and an aqueous medium are added to cause phase inversion, and an alkaline substance is added, and then O / W Disclosed is a method for producing an electrostatic charge developing toner, in which a resin particle dispersion obtained by forming an organic resin emulsion particle and further removing an organic solvent from the O / W resin emulsion particle dispersion is aggregated and united. ing.

WO2010 / 027071 JP 2007-114398 A JP 2008-33057 A

In the emulsion aggregation method, various binder resins such as crystalline or amorphous may be combined by aggregating resin particles to simultaneously satisfy several properties required for the toner. However, since this method uses a very unstable reaction of agglomeration of resin particles in an aqueous solvent, there is a problem that the particle size varies and the particle size distribution becomes broad. When the particle size distribution is broad, the fluidity, which is the basic performance of the toner, is deteriorated, causing problems such as toner scattering and fogging. Furthermore, because of the presence of toners having greatly different particle size differences, the composition may also vary, resulting in problems such as storage stability, toner scattering, and low-temperature fixability.
An object of the present invention is to provide a method for producing an electrophotographic toner having a sharp particle size distribution, achieving both low-temperature fixability and storage stability, and improving toner scattering, and an electrophotographic toner obtained by the production method. It is to provide.

  The present inventors have found that the factors affecting the toner particle size distribution, low-temperature fixability, storage stability, and toner scattering are the state of the binder resin constituting the toner and the toner when the toner is produced by the emulsion aggregation method. The surface state in an aqueous medium was considered and examined. As a result, an emulsion aggregation method in which amorphous polyester obtained from crystalline polyester and a specific alcohol component is melt-mixed and aggregated into a core, and amorphous polyester obtained from a specific alcohol component different from the core is used as a shell. It has been found that by using the toner, an electrophotographic toner having a core-shell structure in which the toner particle size distribution is sharp, low-temperature fixability and storage stability are compatible, and toner scattering is improved can be obtained.

That is, the present invention provides the following [1] and [2].
[1] A method for producing a core-shell type electrophotographic toner comprising the following steps (1) to (4):
Step (1): A crystalline polyester (a) and an amorphous polyester (b) obtained by polycondensation of an alcohol component containing 80 mol% or more of a propylene oxide adduct of bisphenol A and a carboxylic acid component are melt mixed. Step of emulsifying in an aqueous medium to obtain resin particles (A) Step (2): Step of aggregating resin particles (A) to obtain aggregated particles Step (3): In the dispersion of aggregated particles Adding resin particles (C) containing amorphous polyester (c) obtained by polycondensation of an alcohol component containing 80 mol% or more of an ethylene oxide adduct of bisphenol A and a carboxylic acid component, Step (4): The temperature of the system containing the core-shell particles is maintained at a temperature of 5 ° C. lower than the glass transition point of the amorphous polyester (c), and united. The electrophotographic toner obtained by the process of the step of obtaining Asher particles [2] above [1].

  According to the present invention, it is possible to provide an electrophotographic toner having a sharp particle size distribution, having both low-temperature fixability and storage stability, and improved toner scattering, and a method for producing the same.

<Method for producing electrophotographic toner>
The method for producing an electrophotographic toner of the present invention includes the following steps (1) to (4).
Step (1): A crystalline polyester (a) and an amorphous polyester (b) obtained by polycondensation of an alcohol component containing 80 mol% or more of a propylene oxide adduct of bisphenol A and a carboxylic acid component are melt mixed. Step of emulsifying in an aqueous medium to obtain resin particles (A) Step (2): Step of aggregating resin particles (A) to obtain aggregated particles Step (3): In the dispersion of aggregated particles Adding resin particles (C) containing amorphous polyester (c) obtained by polycondensation of an alcohol component containing 80 mol% or more of an ethylene oxide adduct of bisphenol A and a carboxylic acid component, Step (4): The temperature of the system containing the core-shell particles is maintained at a temperature of 5 ° C. lower than the glass transition point of the amorphous polyester (c), and united. Obtaining a Asher particles

The reason why the toner for electrophotography obtained by the production method of the present invention has a sharp particle size distribution, achieves both low-temperature fixability and storage stability, and has low toner scattering is not clear, but is considered as follows. It is done.
According to the method of the present invention, first, an amorphous polyester (a) obtained by polycondensation of a crystalline polyester (a), an alcohol component containing 80 mol% or more of a propylene oxide adduct of bisphenol A and a carboxylic acid component ( b) is melt mixed and emulsified in an aqueous medium to obtain resin particles (A), which are agglomerated. In particular, a propylene oxide adduct of bisphenol A has a propylene oxide portion having moderate hydrophobicity. Therefore, when a colorant, a release agent, or the like is contained in the toner core portion, it is considered that a uniform and strong core portion can be formed.
Next, resin particles (C) containing an amorphous polyester (c) obtained by polycondensation of an alcohol component containing 80 mol% or more of an ethylene oxide adduct of bisphenol A and a carboxylic acid component are added. The core-shell aggregated particles having a shell portion as a shell portion are obtained. Since the ethylene oxide adduct of bisphenol A has an ethylene oxide portion having an appropriate hydrophilicity and an aromatic ring, the core portion is uniformly coated with an aqueous medium. It is considered that it can be stably dispersed therein. Therefore, it is considered that the toner obtained thereby has a sharp particle size distribution. Further, according to the production method of the present invention, since the particle size of the obtained toner is sharp, the composition such as the amount and distribution of the crystalline polyester, the thickness of the core and the shell, etc. are uniform, so that the printing It is considered that the melting behavior and chargeability are uniform, and the low-temperature fixability is excellent. Further, since the shape is uniform and the shell is uniformly coated, it is considered that an electrophotographic toner having excellent storage stability can be obtained. Further, since the obtained toner has a small amount of fine powder, it is considered that toner scattering can be suppressed.

First, each component used in the present invention will be described.
[Resin particles (A)]
The resin particles (A) used in the present invention (hereinafter, also simply referred to as “resin particles (A)”) include an alcohol component containing 80 mol% or more of crystalline polyester (a) and a propylene oxide adduct of bisphenol A. An amorphous polyester (b) obtained by polycondensation with a carboxylic acid component is melt-mixed and emulsified in an aqueous medium. The resin particle (A) may be a particle consisting of only a resin or a colorant-containing resin particle containing a colorant. From the viewpoint of suppressing the generation of coarse particles during aggregation, a colorant is used. The colorant-containing resin particles are preferably contained.
When the resin particles (A) are particles made of only a resin, in the step (2) described in detail later, it is obtained by subjecting the colorant to surface treatment or using a dispersant. It is preferable to further use colorant particles, or colorant-containing resin particles obtained by adding a colorant to resin particles.
When the resin particles (A) are colorant-containing resin particles, from the viewpoint of toner image density, the colorant content is 100 parts by weight of the resin constituting the colorant-containing resin particles. Preferably it is 1-20 weight part, More preferably, it is 5-10 weight part, More preferably, it is 6-8 weight part.

(Coloring agent)
As the colorant, pigments and dyes are used, and pigments are preferable from the viewpoint of toner image density.
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, indico series, phthalocyanine series, and aniline black series.
A coloring agent can be used individually or in combination of 2 or more types.

In the present invention, the resin constituting the resin particles (A) contains the crystalline polyester (a) from the viewpoint of low-temperature fixability of the toner.
The content of the crystalline polyester (a) in the resin particles (A) is preferably 1 with respect to the resin constituting the resin particles (A) from the viewpoint of improving the low-temperature fixability of the toner and preventing hot offset. -50 wt%, more preferably 5-40 wt%, still more preferably 7-30 wt%, particularly preferably 10-20 wt%.

The resin particle (A) is an alcohol component further containing 80 mol% or more of a propylene oxide adduct of bisphenol A from the viewpoint of improving storage stability and chargeability while maintaining low-temperature fixability of the toner and preventing hot offset. And an amorphous polyester (b) obtained by polycondensation of a carboxylic acid component (hereinafter also simply referred to as “amorphous polyester (b)”).
The total amount of the crystalline polyester (a) and the amorphous polyester (b) in the resin particles (A) is preferably relative to the resin constituting the resin particles (A) from the viewpoint of improving the low-temperature fixability of the toner. Is 50 to 100% by weight, more preferably 80 to 100% by weight, still more preferably 90 to 100% by weight. The weight ratio ((a) / (b)) between the crystalline polyester (a) and the amorphous polyester (b) in the resin particles (A) improves the low-temperature fixability, storage stability and chargeability of the toner. From the viewpoint of preventing hot offset, preferably 5/95 to 50/50, more preferably 5/95 to 40/60, more preferably 7/93 to 35/65, and still more preferably 7/93 to 30 /. 70, particularly preferably 10/90 to 20/80.

The resin particle (A) is a resin other than the crystalline polyester (a) and the amorphous polyester (b), for example, a styrene acrylic copolymer, an epoxy resin, a polycarbonate, a polyurethane, etc., as long as the effects of the present invention are not impaired. The resin may be contained.
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. If necessary, reinforcing fillers such as fibrous substances, antioxidants, You may contain additives, such as anti-aging agent.

(Crystalline polyester (a))
In the present invention, the crystalline polyester (a) is a 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 0.6 to 1.4. This crystallinity index is preferably 0.8 to 1.3, more preferably 0.9 to 1.2, and still more preferably 0.9 to 1.1 from the viewpoint of low-temperature fixability of the toner.
The crystalline polyester (a) preferably has an acid group at the molecular end from the viewpoint of emulsifiability. Examples of the acid group include a carboxyl group, a sulfonic acid group, a phosphonic acid group, and a sulfinic acid. Among these, a carboxyl group is preferable from the viewpoints of resin dispersibility and toner storage stability.

The melting point of the crystalline polyester (a) is preferably 50 to 150 ° C., more preferably 55 to 130 ° C., still more preferably 60 to 120 ° C., and particularly preferably 60 from the viewpoint of low-temperature fixability and storage stability of the toner. It is -100 degreeC, Most preferably, it is 60-80 degreeC.
From the same viewpoint, the softening point of the crystalline polyester (a) is preferably 50 to 140 ° C, more preferably 55 to 130 ° C, more preferably 60 to 110 ° C, and still more preferably 60 to 85 ° C.
The number average molecular weight of the crystalline polyester (a) is preferably 1,500 to 50,000, more preferably 1,500 to 10,000, still more preferably 2,000 to 8, from the viewpoint of low-temperature fixability of the toner. , 000.
In addition, crystalline polyester (a) can be used individually or in combination of 2 or more types.
In the present invention, the melting point, softening point and number average molecular weight of the crystalline polyester (a) are determined by the methods described in the examples. When two or more crystalline polyesters (a) are used in combination, the melting point of the crystalline polyester (a) in the present invention is the crystal having the largest weight ratio among the crystalline polyesters (a) contained in the obtained toner. The melting point of the crystalline polyester (a) is the melting point of the crystalline polyester (a) having the lowest melting point when all the crystalline polyesters (a) have the same ratio. A softening point and a number average molecular weight are calculated | required by the method as described in an Example as a mixture of crystalline polyester (a).

The crystalline polyester (a) is preferably obtained by polycondensation reaction of a carboxylic acid component and an alcohol component. The polycondensation reaction is preferably performed at 140 to 200 ° C. in the presence of a catalyst.
Examples of the carboxylic acid component include aliphatic dicarboxylic acids, alicyclic dicarboxylic acids, aromatic dicarboxylic acids, trivalent or higher polyvalent carboxylic acids, anhydrides of these acids, and alkyl (C1 to C3) esters. Among these, aliphatic dicarboxylic acids are preferable from the viewpoint of low-temperature fixability, storage stability, and chargeability of the toner.
Aliphatic dicarboxylic acids include oxalic acid, malonic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, succinic acid, adipic acid, sebacic acid, 1,12-dodecanedioic acid, azelaic acid, n- Examples include dodecyl succinic acid and n-dodecenyl succinic acid. Among these, from the viewpoint of low-temperature fixability, storage stability and chargeability of the toner, sebacic acid and 1,12-dodecanedioic acid are preferable, and sebacic acid is more preferable. .
These can be used alone or in combination of two or more.

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, and trihydric or higher polyhydric alcohols. Among these, the crystallinity of polyester is promoted. From the viewpoint of improving the low-temperature fixability of the toner, an aliphatic diol having 2 to 12 main chain carbon atoms is preferred.
Among the aliphatic diols having 2 to 12 main chain carbon atoms, α, ω-linear alkanediols are preferable from the viewpoint of promoting the crystallinity of the polyester and improving the low-temperature fixability of the toner. Twelve α, ω-linear alkanediols are more preferred.
Examples of the α, ω-linear alkanediol include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1 , 7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,12-dodecanediol, etc. Among these, low-temperature fixability and storage stability of the toner From the viewpoint of chargeability, 1,6-hexanediol and 1,9-nonanediol are preferred.
Examples of other aliphatic diols having 2 to 12 carbon atoms in the main chain include neopentyl glycol and 1,4-butenediol.

  The alcohol component can be used alone or in combination of two or more. From the viewpoint of promoting the crystallinity of the polyester, the alcohol component contains 80 to 100 moles of an aliphatic diol having 2 to 12 carbon atoms in the main chain. %, And more preferably 90 to 100 mol%.

From the viewpoint of the efficiency of the condensation polymerization reaction, the catalyst is preferably a tin compound, a titanium compound or the like, and more preferably a tin compound. Examples of tin compounds include tin dioctylate and dibutyltin oxide. Examples of the titanium compound include titanium diisopropylate bistriethanolamate.
Although there is no restriction | limiting in the usage-amount of a catalyst, Preferably it is 0.01-1 weight part with respect to 100 weight part of total amounts of a carboxylic acid component and an alcohol component, More preferably, it is 0.1-0.6 weight part. .

  The polycondensation reaction is preferably carried out by adding a carboxylic acid component and an alcohol component to a reaction vessel and maintaining at 140 to 200 ° C. for 5 to 15 hours. It is more preferable to carry out the reaction by maintaining the reaction, reducing the pressure to 5.0 to 20 kPa, and maintaining for 1 to 10 hours.

(Amorphous polyester (b))
In the present invention, the amorphous polyester (b) contained in the resin particles (A) is a polyester obtained by polycondensation of an alcohol component containing 80 mol% or more of a propylene oxide adduct of bisphenol A and a carboxylic acid component. From the viewpoint of storage stability and chargeability of the toner, it is an amorphous polyester.
In the present invention, the amorphous polyester is a polyester having a crystallinity index of more than 1.4 or less than 0.6.
From the viewpoint of low-temperature fixability of the toner, the crystallinity index of the amorphous polyester (b) is preferably less than 0.6 or more than 1.4 and 4 or less, more preferably less than 0.6 or 1.5 or more and 4 Hereinafter, more preferably less than 0.6 or 1.5 or more and 3 or less, and further preferably 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 (b) is preferably an amorphous polyester having an acid group at the molecular end from the viewpoint of emulsifiability. Examples of the acid group include a carboxyl group, a sulfonic acid group, a phosphonic acid group, and a sulfinic acid. Among these, a carboxyl group is preferable from the viewpoint of promoting emulsification of the polyester.

The amorphous polyester (b) can be produced by a polycondensation reaction between a carboxylic acid component and an alcohol component in the same manner as the crystalline polyester (a).
Examples of the carboxylic acid component include dicarboxylic acid, succinic acid substituted with an alkyl group having 1 to 20 carbon atoms or an alkenyl group having 2 to 20 carbon atoms, trivalent or higher polyvalent carboxylic acid, and acid anhydrides thereof and the like Alkyl (1 to 3 carbon atoms) ester, and the like. Among these, dicarboxylic acid is preferable.
Examples of the dicarboxylic acid include phthalic acid, isophthalic acid, terephthalic acid, sebacic acid, fumaric acid, maleic acid, adipic acid, azelaic acid, succinic acid, and cyclohexanedicarboxylic acid. Among these, terephthalic acid and fumaric acid are preferable. .
Examples of the succinic acid substituted with an alkyl group having 1 to 20 carbon atoms or an alkenyl group having 2 to 20 carbon atoms include dodecyl succinic acid, dodecenyl succinic acid, and octenyl succinic acid.
Examples of the trivalent or higher polyvalent carboxylic acid include trimellitic acid, 2,5,7-naphthalenetricarboxylic acid, pyromellitic acid, and the like. Among these, trimellitic acid and acid anhydride thereof from the viewpoint of offset resistance. Things are preferred.
These carboxylic acid components can be used alone or in combination of two or more.
The amorphous polyester (b) is a carboxylic acid containing 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 offset resistance of the toner. It is preferable to use at least one amorphous polyester (b) obtained by using the components.

From the viewpoint of sharpening the toner particle size distribution and improving the low-temperature fixability, the amorphous polyester (b) is a propylene oxide adduct of bisphenol A, that is, polyoxypropylene-2,2- It contains 80 mol% or more of bis (4-hydroxyphenyl) propane.
Examples of the alcohol component other than the propylene oxide adduct of bisphenol A include an ethylene oxide adduct of bisphenol A, an aliphatic diol having 2 to 12 main chain carbon atoms, a hydrogenated product of bisphenol A, a trihydric or higher polyhydric alcohol, and the like. Among them, it is preferable to use an ethylene oxide adduct of bisphenol A from the viewpoint of sharpening the particle size distribution of the toner and improving the low-temperature fixability.
Examples of the aliphatic diol having 2 to 12 carbon atoms include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, and 1,6-hexane. Diol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,12-dodecanediol, neopentyl glycol, 1,4-butenediol, etc. It is done.
Examples of the trihydric or higher polyhydric alcohol include glycerin and pentaerythritol.
These alcohol components can be used alone or in combination of two or more.

The glass transition point of the amorphous polyester (b) is preferably 55 to 75 ° C., more preferably 55 to 70 ° C., and still more preferably 58 to 68, from the viewpoint of toner durability, low-temperature fixability and storage stability. ° C.
From the same viewpoint, the softening point of the amorphous polyester (b) is preferably 70 to 165 ° C, more preferably 70 to 140 ° C, still more preferably 90 to 140 ° C, still more preferably 100 to 130 ° C.
When two or more kinds of amorphous polyesters (b) are used in combination, the glass transition point and softening point thereof are each determined by the method described in the examples as a mixture of two or more kinds of amorphous polyesters (b). It refers to the glass transition point and softening point obtained.

The number average molecular weight of the amorphous polyester (b) is preferably 1,000 to 50,000, more preferably 1,000 to 10,000, from the viewpoint of toner durability, low-temperature fixability and storage stability. More preferably, it is 2,000-8,000.
The acid value of the amorphous polyester (b) is preferably 6 to 35 mg KOH / g, more preferably 10 to 35 mg KOH / g, and still more preferably 15 to 35 mg KOH / g, from the viewpoint of emulsification in the aqueous medium of the resin. is there.

[Releasing agent particles]
In the present invention, it is preferable to use release agent particles from the viewpoint of improving the low-temperature fixability and releasability of the toner.
The release agent particles used in the present invention are preferably obtained by using a dispersant with respect to the release agent.
The release agent particles preferably contain a surfactant from the viewpoint of aggregation. In the case of using the surfactant, the content is preferably 0.01 to 10 parts by weight, more preferably 0.1 parts by weight with respect to 100 parts by weight of the release agent, from the viewpoints of aggregability and chargeability of the obtained toner. 1 to 5 parts by weight, more preferably 0.5 to 2 parts by weight.
The volume median particle size (D ₅₀ ) of the release agent particles is preferably 0.1 to 1 μm, more preferably 0.1 to 0.7 μm, and still more preferably, from the viewpoint of preventing chargeability and hot offset of the toner. 0.1 to 0.5 μm. 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.
The coefficient of variation (CV value) (%) of the particle size distribution of the release agent particles is preferably 15 to 50%, more preferably 15 to 40%, and still more preferably 15 to 35%, from the viewpoint of toner chargeability. is there.
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 median particle size (μm)] × 100

(Release agent)
As release agents, low molecular weight polyolefins such as polyethylene, polypropylene and polybutene; silicones having a softening point upon heating; fatty acid amides such as oleic acid amide and stearic acid amide; carnauba wax, rice wax and candelilla wax Plant waxes such as beeswax; animal waxes such as beeswax; mineral / petroleum waxes such as montan wax, paraffin wax, and Fischer-Tropsch wax. These release agents can be used alone or in combination of two or more.
The melting point of the release agent is preferably 65 to 100 ° C., more preferably 75 to 95 ° C., still more preferably 75 to 90 ° C., and still more preferably, from the viewpoint of low-temperature fixability and storage stability of the toner and chargeability. 80-90 ° C.
In this invention, melting | fusing point of a mold release agent is calculated | required by the method as described in an Example. When two or more release agents are used in combination, the melting point of the release agent in the present invention is the melting point of the release agent having the largest weight ratio among the release agents contained in the obtained toner. Are the same, the melting point of the release agent having the lowest melting point is used.
The amount of the release agent used is preferably 1 to 20 parts by weight, more preferably 2 to 15 parts by weight, based on 100 parts by weight of the resin in the toner, from the viewpoint of toner releasability and chargeability.

(Manufacture of release agent particles)
The release agent particles are preferably obtained as a dispersion of release agent particles by dispersing the release agent in an aqueous medium.
The dispersion of the release agent particles is preferably obtained by dispersing the release agent and the aqueous medium using a disperser in the presence of a surfactant at a temperature equal to or higher than the melting point of the release agent. The disperser used is preferably a homogenizer, an ultrasonic disperser or the like.
The aqueous medium and surfactant used in the production are preferably those used when obtaining a resin mixture of the crystalline polyester (a) and the amorphous polyester (b).

[Flocculant]
In the present invention, a flocculant is preferably used in order to efficiently obtain the core particle dispersion and the core-shell particle dispersion.
As the aggregating agent, a quaternary salt cationic surfactant, an organic aggregating agent such as polyethyleneimine; an inorganic aggregating agent such as an inorganic metal salt, an inorganic ammonium salt, or a bivalent or higher metal complex is 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.

[Resin particles (C)]
The resin particles (C) used in the present invention are obtained by polycondensation of an alcohol component containing 80 mol% or more of an ethylene oxide adduct of bisphenol A and a carboxylic acid component from the viewpoint of storage stability and chargeability of the toner. Amorphous polyester (c) (hereinafter also simply referred to as “amorphous polyester (c)”).
The glass transition point of the resin particle (C) is appropriately determined depending on the glass transition point of the resin such as the amorphous polyester (c) constituting the resin particle (C), the type and amount of the additive, etc. From the viewpoint of durability, low-temperature fixability, and storage stability, it is preferably 55 ° C. or higher, more preferably 55 to 75 ° C., more preferably 55 to 70 ° C., and further preferably 55 to 65 ° C.

The content of the amorphous polyester (c) in the resin particles (C) is preferably 70% by weight or more, more preferably 80% by weight or more, more preferably 90%, from the viewpoint of storage stability and chargeability of the toner. % By weight or more, more preferably substantially 95% by weight or more.
In addition to the amorphous polyester (c), the resin particles (C) are known resins that are usually used in toners, such as the above-mentioned crystalline polyester (a), styrene acrylic copolymer, epoxy resin, polycarbonate, polyurethane. A resin such as
The resin particles (C) are obtained by the same method as the method for producing the resin particles (A) described above, and the same alkaline aqueous solution, surfactant and aqueous medium can be suitably used.

(Amorphous polyester (c))
The amorphous polyester (c) contained in the resin particles (C) is a polyester obtained by polycondensation of an alcohol component containing 80 mol% or more of an ethylene oxide adduct of bisphenol A and a carboxylic acid component. From this point of view, it is an amorphous polyester.
From the viewpoint of low-temperature fixability of the toner, the crystallinity index of the amorphous polyester (c) is preferably less than 0.6 or more than 1.4 and less than 4, more preferably less than 0.6 or 1.5 or more and 4 Hereinafter, more preferably less than 0.6 or 1.5 or more and 3 or less, particularly preferably 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 (c) is preferably an amorphous polyester having an acid group at the molecular end. Examples of the acid group include a carboxyl group, a sulfonic acid group, a phosphonic acid group, and a sulfinic acid. Among these, a carboxyl group is preferable from the viewpoint of promoting emulsification of the polyester.

The amorphous polyester (c) can be produced by subjecting a carboxylic acid component and an alcohol component to a polycondensation reaction in the same manner as the crystalline polyester (a).
Examples of the carboxylic acid component include dicarboxylic acid, succinic acid substituted with an alkyl group having 1 to 20 carbon atoms or an alkenyl group having 2 to 20 carbon atoms, trivalent or higher polyvalent carboxylic acid, and acid anhydrides thereof and the like Alkyl (1 to 3 carbon atoms) ester, and the like. Among these, dicarboxylic acid is preferable.
Examples of the dicarboxylic acid include phthalic acid, isophthalic acid, terephthalic acid, sebacic acid, fumaric acid, maleic acid, adipic acid, azelaic acid, succinic acid, and cyclohexanedicarboxylic acid. Among these, terephthalic acid and fumaric acid are preferable. .
Examples of the succinic acid substituted with an alkyl group having 1 to 20 carbon atoms or an alkenyl group having 2 to 20 carbon atoms include dodecyl succinic acid, dodecenyl succinic acid, and octenyl succinic acid.
Examples of the trivalent or higher polyvalent carboxylic acid include trimellitic acid, 2,5,7-naphthalenetricarboxylic acid, pyromellitic acid, and the like. Among these, trimellitic acid and acid anhydride thereof from the viewpoint of offset resistance. Things are preferred.
These carboxylic acid components can be used alone or in combination of two or more.
The amorphous polyester (c) is a carboxylic acid containing 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 offset resistance of the toner. It is preferable to use at least one amorphous polyester (c) obtained using the components.

From the viewpoint of sharpening the particle size distribution and improving the storage stability, the amorphous polyester (c) is an ethylene oxide adduct of bisphenol A, that is, polyoxyethylene-2,2-bis (4) as an alcohol component. -Contains 80 mol% or more of hydroxyphenyl) propane.
Examples of alcohol components other than bisphenol A ethylene oxide adducts include bisphenol A propylene oxide adducts, aliphatic diols having 2 to 12 main chain carbon atoms, hydrogenated bisphenol A, and trihydric or higher polyhydric alcohols. Among them, it is preferable to use a propylene oxide adduct of bisphenol A from the viewpoint of sharpening the particle size distribution of the toner and improving the low-temperature fixability.
Examples of the aliphatic diol having 2 to 12 carbon atoms include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, and 1,6-hexane. Diol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,12-dodecanediol, neopentyl glycol, 1,4-butenediol, etc. It is done.
Examples of the trihydric or higher polyhydric alcohol include glycerin and pentaerythritol.
These alcohol components can be used alone or in combination of two or more.

The glass transition point of the amorphous polyester (c) is preferably 55 to 75 ° C., more preferably 55 to 70 ° C., and still more preferably 58 to 68, from the viewpoint of toner durability, low-temperature fixability and storage stability. ° C.
From the same viewpoint, the softening point of the amorphous polyester (c) is preferably 70 to 165 ° C, more preferably 70 to 140 ° C, still more preferably 90 to 140 ° C, and particularly preferably 100 to 130 ° C.
In addition, when using 2 or more types of amorphous polyesters (c) in combination, the glass transition point and the softening point are each determined by the method described in the examples as a mixture of 2 or more types of amorphous polyesters (c). It refers to the glass transition point and softening point obtained.

The number average molecular weight of the amorphous polyester (c) is preferably 1,000 to 50,000, more preferably 1,000 to 10,000, from the viewpoint of toner durability, low-temperature fixability and storage stability. More preferably, it is 2,000-8,000.
The acid value of the amorphous polyester (c) is preferably 6 to 35 mgKOH / g, more preferably 10 to 35 mgKOH / g, still more preferably 15 to 35 mgKOH / g, from the viewpoint of emulsification in the aqueous medium of the resin. is there.

  In addition, in this invention, what modified | denatured each of crystalline polyester (a), amorphous polyester (b), and (c) 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.

Next, each step in the method for producing an electrophotographic toner of the present invention will be described.
[Step (1)]
In step (1), crystalline polyester (a) and amorphous polyester (b) obtained by polycondensation of an alcohol component containing 80 mol% or more of a propylene oxide adduct of bisphenol A and a carboxylic acid component are melted. It is a step of mixing and emulsifying in an aqueous medium to obtain resin particles (A).

The method of melt mixing includes a method of melt-mixing polyester, a method of mixing by dissolving in an organic solvent, and a method of mixing while melting in an aqueous medium. From the viewpoint of easy dispersion and uniform melt-mixing, A method of mixing while melting in an aqueous medium is preferred.
Resin particles (A) melt amorphous polyester (b) obtained by polycondensation of a crystalline polyester (a) and an alcohol component containing 80 mol% or more of a propylene oxide adduct of bisphenol A and a carboxylic acid component. It is produced by a method of mixing and emulsifying in an aqueous medium, but the above-mentioned optional components such as a colorant can be simultaneously dispersed during melt mixing or emulsification, and the colorant is simultaneously mixed during melt mixing. It is preferable to mix.
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 (a), amorphous polyester (b), alkaline aqueous solution, and colorant are melted and mixed to obtain a resin mixture.
The crystalline polyester (a) and the amorphous polyester (b) may be premixed, but are obtained by adding at the same time when adding the alkaline aqueous solution and optional components, and melting and mixing them. From the viewpoint of low-temperature fixability of the toner, a method of obtaining a resin mixture by melting and mixing the crystalline polyester (a), the amorphous polyester (b), the alkaline aqueous solution, and the above optional components is preferable. .
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. . The concentration of alkali in the aqueous alkali solution is preferably 1 to 30% by weight, more preferably 1 to 25% by weight, and still more preferably 1.5 to 20% by weight.

Examples of the surfactant include nonionic surfactants, anionic surfactants, and cationic surfactants. Among them, nonionic surfactants are preferable, and nonionic surfactants and anionic surfactants are preferred. It is more preferable to use an active agent or 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.
When a nonionic surfactant and an anionic surfactant are used in combination, the weight ratio of the nonionic surfactant to the anionic surfactant (nonionic surfactant / anionic surfactant) is: From the viewpoint of sufficiently emulsifying the resin, it is preferably 0.3 to 10, more preferably 0.5 to 5.

Nonionic surfactants include polyoxyethylene nonyl phenyl ether, polyoxyethylene oleyl ether, polyoxyethylene alkyl aryl ethers such as polyoxyethylene lauryl ether, polyoxyethylene alkyl ethers, polyethylene glycol monolaurate , Polyoxyethylene fatty acid esters such as polyethylene glycol monostearate and polyethylene glycol monooleate, and oxyethylene / oxypropylene block copolymers. Among these, from the viewpoint of emulsion stability of the resin, polyoxyethylene Alkyl ethers are preferred.
Examples of the anionic surfactant include dodecyl benzene sulfonic acid, sodium dodecyl benzene sulfonate, sodium dodecyl sulfate, sodium alkyl ether sulfate, etc. Among these, from the viewpoint of emulsion stability of the resin, sodium dodecyl benzene sulfonate, Sodium alkyl ether sulfate is preferred.
Examples of the cationic surfactant include alkylbenzene dimethyl ammonium chloride, alkyl trimethyl ammonium chloride, distearyl ammonium chloride and the like.

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

As a method for obtaining the resin mixture, the crystalline polyester (a), the amorphous polyester (b), the alkaline aqueous solution, and the above optional components, more preferably, a surfactant is put in a container and stirred with a stirrer. A method of melting and uniformly mixing the resin is preferable.
The temperature at which the resin is melted and mixed is preferably equal to or higher than the glass transition point of the amorphous polyester (b), and more preferably equal to or higher than the melting point of the crystalline polyester (a) from the viewpoint of obtaining uniform 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. From the viewpoint of environmental properties, the content of water in the aqueous medium is preferably 80% by weight or more, more preferably 90% by weight or more, more preferably 95% by weight. % Or more, more preferably substantially 100% by weight. The water used is preferably deionized water or distilled water.
As components other than water, organic solvents that dissolve in water such as alkyl 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. Among these, from the viewpoint of preventing mixing into the toner, an alkyl alcohol having 1 to 5 carbon atoms that does not dissolve the polyester is preferable, and methanol, ethanol, isopropanol, and butanol are more preferable.

  The temperature in the system when adding the aqueous medium is preferably equal to or higher than the glass transition point of the amorphous polyester (b), and more preferably equal to or higher than the melting point of the crystalline polyester (a) from the viewpoint of obtaining homogeneous resin particles.

  The addition rate of the aqueous medium is preferably 0.1 to 50 weights with respect to 100 parts by weight 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. Part / minute, more preferably 0.1 to 30 parts by weight / minute, more preferably 0.5 to 10 parts by weight / minute, still more preferably 0.5 to 5 parts by weight / minute. In addition, there is no restriction | limiting in the addition rate of the aqueous medium after completion | finish of phase inversion.

  The amount of the aqueous medium used is preferably 100 to 2000 parts by weight, more preferably 100 to 100 parts by weight with respect to 100 parts by weight of the resin constituting the resin particles (A) from the viewpoint of obtaining uniform aggregated particles in the subsequent aggregation step. 1500 parts by weight, more preferably 150 to 500 parts by weight. The solid content concentration is preferably 7 to 50% by weight, more preferably 10 to 40% by weight, more preferably 20 to 40% by weight, from the viewpoint of the stability and ease of handling of the obtained resin particle dispersion. More preferably, it is 25 to 35% by weight. In addition, solid content is the total amount of non-volatile components, such as resin and surfactant.

The volume median particle size of the resin particles (A) in the dispersion containing the obtained resin particles (A) is preferably from 0.02 to 2 μm, more preferably from the viewpoint of obtaining a high-image toner. It is 02 to 1.5 μm, more preferably 0.05 to 1 μm, and particularly preferably 0.05 to 0.5 μm.
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, more preferably 30% or less, and still more preferably, from the viewpoint of obtaining a high-image toner. Is 28% or less.

In addition, before the next step (2), that is, the aggregation step, the aqueous dispersion containing the resin particles (A) obtained in this step (1) is melted below the melting point of the crystalline polyester (a). It is preferable to include a step of holding for 1 hour or more at a temperature of 25 ° C. or lower than the melting point of), and more preferable to include a step of holding for 3 hours or more.
By maintaining the temperature within this range, crystallization of the crystalline polyester (a) can be promoted, and the low-temperature fixability and storage stability of the finally obtained toner can be improved.

[Step (2)]
Step (2) is a step of aggregating the resin particles (A) to obtain aggregated particles.
In the present invention, it is preferable to use the above-mentioned flocculant in order to efficiently perform the aggregation.
The use amount of the flocculant is preferably 50 parts by weight or less, more preferably 40 parts by weight or less, and further preferably 30 parts by weight with respect to 100 parts by weight of the resin constituting the resin particles (A), from the viewpoint of toner charging properties. From the viewpoint of the cohesiveness of the resin particles, it is preferably 1 part by weight or more, more preferably 3 parts by weight or more, and further preferably 5 parts by weight or more. In consideration of the above points, the amount of the monovalent salt used is preferably 1 to 50 parts by weight, more preferably 3 to 40 parts by weight with respect to 100 parts by weight of the resin constituting the resin particles (A). More preferably, it is 5-35 weight part.

  As the aggregating method, it is preferable to add the aggregating agent as an aqueous solution dropwise to a container containing the 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 aggregation control and shortening of toner production time, the dropping time of the aggregating agent is preferably 1 to 120 minutes. Further, from the viewpoint of aggregation control, the dropping temperature is preferably 0 to 40 ° C.

Further, in the step (2), from the viewpoint of improving the low-temperature fixability and releasability of the toner, it is preferable to use the aforementioned release agent particles.
The release agent particles are preferably prepared in advance as a dispersion and mixed with an aqueous dispersion containing the resin particles (A) before adding the above-mentioned flocculant.

  The volume-median particle size of the obtained aggregated particles is preferably 1 to 10 μm, more preferably 2 to 9 μm, from the viewpoint of reducing the particle size and reducing the amount of scattering of the obtained toner in a printer such as a printer. More preferably, it is 3-6 micrometers. The CV value is preferably 30% or less, more preferably 28% or less, and still more preferably 25% or less.

[Step (3)]
Step (3) is an amorphous product obtained by polycondensing an alcohol component containing 80 mol% or more of an ethylene oxide adduct of bisphenol A and a carboxylic acid component to the dispersion of aggregated particles obtained in step (2). This is a step of adding core particles (C) containing resin particles (C) to obtain core-shell particles.
In this step, the agglomerated particles and the particles of the resin particles (C) containing the amorphous polyester (c) added as a shell part are agglomerated and adhered to the surface of the agglomerated particles to form core-shell particles.

In this step, first, a dispersion of resin particles (C) containing amorphous polyester (c) (hereinafter also referred to as “resin particle (C) dispersion”) is prepared, and then the resin particles (C It is preferable to add the dispersion liquid to the dispersion liquid of the aggregated particles obtained in the step (2) to adhere the resin particles (C) to the aggregated particles to obtain the core-shell particles.
From the viewpoint of more uniformly attaching the resin particles (C) to the aggregated particles, it is preferable to add an aqueous medium to the aggregated particle dispersion and dilute it before adding the resin particle (C) dispersion.
When the resin particle (C) dispersion is added, the aggregating agent may be used to efficiently attach the resin particles (C) to the aggregated particles.
The addition method when adding the resin particle (C) dispersion is a method of simultaneously adding the flocculant and the resin particle (C) dispersion, or a method of alternately adding the flocculant and the resin particle (C) dispersion. A method of adding the resin particle (B) dispersion while gradually raising the temperature of the aggregated particle dispersion is preferable. According to such a method, it is possible to prevent a decrease in cohesiveness of the core particles and the resin particles (C) due to a decrease in the coagulant concentration. Among these, it is preferable to add the resin particle (C) dispersion while gradually raising the temperature of the aggregated particle dispersion from the viewpoint of toner productivity and manufacturing simplicity.

In step (3), the temperature in the system at the time of addition of resin particles (C) and / or after completion of the addition is used for the added release agent particles when the release agent particles are used in step (2). It is preferable to hold at a temperature lower than the melting point of the release agent and at least 10 ° C. lower than the glass transition point of the amorphous polyester (c). Although the temperature at the time of addition of the resin particles (C) may not belong to the above range, in that case, the temperature after the addition is preferably within the above range.
Low temperature fixing of the obtained toner by setting the temperature when the resin particles (C) are added to a temperature lower than the melting point of the release agent and 10 ° C. lower than the glass transition point of the amorphous polyester (c) Property and storage stability can be improved, and charging property can be improved. The reason for this is not clear, but it is also considered that since the core-shell particles are not fused, the generation of coarse particles is suppressed and the exposure of the release agent is suppressed.

  The addition amount of the resin particles (C) is the weight ratio of the resin particles (C) to the resin particles (A) (resin particles (C) / resin particles) from the viewpoint of low temperature fixability, chargeability and storage stability of the toner (A)) is preferably 0.3 to 1.5, more preferably 0.3 to 1.0, and still more preferably 0.35 to 0.75.

  The resin particle (C) dispersion may be added continuously over a certain period of time, may be added at once, or may be added in multiple portions, but the resin particles (C) From the viewpoint of facilitating selective aggregation to the core particles, it is preferable to add continuously over a certain period of time, or to add divided into multiple times, among them, the viewpoint of promoting selective aggregation and From the viewpoint of production efficiency, it is more preferable to add continuously over a certain period of time. The addition time in the case of continuous addition is preferably 1 to 10 hours, more preferably 3 to 8 hours from the viewpoint of obtaining uniform core-shell particles and shortening of the production time.

Aggregation is stopped when the addition of the entire amount of the resin particles (C) has been completed. From the viewpoint of preventing unnecessary aggregation, it is preferable to stop aggregation by adding an aggregation stopper.
As the aggregation terminator, a surfactant is preferable, and an anionic surfactant is more preferable. Anionic surfactants include alkyl ether sulfates, alkyl sulfates, and linear alkyl benzene sulfonates. The aggregation terminators can be used alone or in combination of two or more.
The addition amount of the aggregation stopper is preferably 0.1 to 15 parts by weight with respect to 100 parts by weight of the total resin in the system, from the viewpoint of reducing the aggregation stopping property and the residual of the aggregation stopper in the toner. Preferably it is 0.1-10 weight part, More preferably, it is 0.1-8 weight part. The aggregation terminator may be added in any form, but is preferably added as an aqueous solution from the viewpoint of productivity.

[Step (4)]
In the step (4), the temperature of the system containing the core-shell particles obtained in the step (3) is maintained at a temperature of 5 ° C. lower than the glass transition point of the amorphous polyester (c), and the united core-shell This is a step of obtaining particles.
In addition, process (4) can also be performed simultaneously with process (3). That is, when adding the resin particles (C), it is adjusted to the temperature range and united. In this case, it is not necessary to maintain the temperature range after the addition. However, when it is necessary to control the particle size and shape, it is preferable to perform the step (3) and the step (4) separately. That is, at the time of addition, the addition is preferably performed at a temperature lower than 5 ° C. below the glass transition point of the amorphous polyester (c), and after completion of the addition, the temperature is preferably maintained at a temperature of 5 ° C. lower than the glass transition point. .

Further, the holding temperature after addition is 5 ° C. lower than the glass transition point of the amorphous polyester (c), preferably 2 ° C. lower than the glass transition point and lower than the melting point of the crystalline polyester (a). More preferably, the melting point, the storage stability of the toner, the charging property, and the toner productivity can be improved by setting the glass transition point or higher and the melting point of the crystalline polyester (a) or lower.
By satisfying these conditions, the crystalline state of the crystalline polyester that exhibits low-temperature fixability is maintained, and the exposure of the crystalline polyester to the toner surface, which causes a decrease in storage stability and chargeability of the toner, is suppressed. Thus, it is considered that the shell portion can be uniformly fused, and as a result, toner scattering can be suppressed and a toner having both good low-temperature fixability and storage stability can be obtained.
Furthermore, from the viewpoints of fusing property, toner storage stability, chargeability, and toner productivity, in this step, it is preferable to hold at a temperature of 2 ° C. lower than the glass transition point of the resin particles (C), It is more preferable to hold at a temperature of 5 ° C. or higher than the glass transition point of the resin particles (C).
The holding time in this step is preferably 1 to 24 hours, more preferably 1 to 12 hours, and further preferably 1 to 6 hours, from the viewpoints of particle fusing property, storage stability, chargeability and toner productivity. .

  From the viewpoint of improving the storage stability and chargeability of the toner, the concentration of the flocculant in the combined core-shell particle dispersion obtained in the step (4) is preferably 0.05 to 0.40 mol / L. More preferably, it is 0.05-0.30 mol / L, More preferably, it is 0.10-0.30 mol / L.

  In this step, it is preferable to confirm the progress of fusion by monitoring the circularity of the generated core-shell particles. Circularity is monitored by the method described in the examples. From the viewpoint of improving the storage stability and chargeability of the toner, the circularity of the core-shell particles contained in the finally obtained core-shell particle dispersion is preferably 0.950 to 0.980, more preferably 0. .950 to 0.970, more preferably 0.955 to 0.965.

BET specific surface area by nitrogen adsorption method of the core-shell particles contained in the core-shell particle dispersion, from the viewpoint of improving the storage stability and chargeability of the toner, preferably 1.0 m ² / g or more 4.0m below ² / g More preferably, it is 1.0-3.0 m < ² > / g, More preferably, it is 1.5-3.0 m < ² > / g, More preferably, it is 1.5-2.5 m < ² > / g.
The volume median particle size of the core-shell particles in the core-shell particle dispersion is preferably 2 to 10 μm, more preferably 2 to 8 μm, more preferably 2 to 7 μm, and more preferably from the viewpoint of improving the image quality of the toner. It is 3-7 micrometers, More preferably, it is 4-6 micrometers.

[Post-processing process]
In the present invention, it is preferable to obtain toner particles by performing a post-treatment step after step (4) and isolating the core-shell particles.
Since the core-shell particles obtained in the step (4) are present in the aqueous medium, it is preferable to first perform solid-liquid separation. For solid-liquid separation, a suction filtration method or the like is preferably used.
It is preferable to perform washing after the solid-liquid separation. In order to ensure sufficient charging characteristics and reliability as a toner, it is preferable to perform washing with an acid in order to remove metal ions on the toner surface. Moreover, since it is preferable to remove the added nonionic surfactant, it is preferable to wash with an aqueous solution below the cloud point of the nonionic surfactant. The washing is preferably performed a plurality of times.
Next, it is preferable to perform drying. The drying method is preferably a vibration type fluidized drying method, a spray drying method, a freeze drying method, a flash jet method or the like. The water content after drying is preferably adjusted to 1.5% by weight or less, more preferably 1.0% by weight or less, from the viewpoint of reducing the amount of toner scattered and charging properties.

<Toner for electrophotography>
(toner)
The particles obtained by drying and the like can be used as they are as the toner of the present invention, but those surface-treated as described below are preferably used as electrophotographic toners.
The softening point of the obtained toner is preferably 60 to 140 ° C., more preferably 65 to 130 ° C., and still more preferably 70 to 120 ° C., from the viewpoint of low temperature fixability and hot offset resistance of the toner. The glass transition point is preferably 30 to 80 ° C., more preferably 40 to 70 ° C. from the viewpoints of low-temperature fixability, durability, and storage stability.
The circularity of the toner is preferably 0.955 to 0.980, more preferably 0.958 to 0.980, and still more preferably 0.960 to 0, from the viewpoints of storage stability, chargeability and cleaning properties of the toner. .975. The circularity of the toner particles can be measured by the method described later. The circularity of the toner is a value obtained by the ratio of the circumference of the circle equal to the projected area / the circumference of the projected image. The more circular the particles are, the closer the circularity is to 1.
The volume median particle size of the toner is preferably 1 to 10 μm, more preferably 2 to 8 μm, more preferably 3 to 7 μm, and still more preferably 4 to 6 μm, from the viewpoint of high image quality and productivity of the toner.
The CV value of the toner is preferably 30% or less, more preferably 27% or less, more preferably 25% or less, and still more preferably 22% or less, from the viewpoints of high image quality and productivity.

(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 external additives include hydrophobic silica, titanium oxide fine particles, alumina fine particles, cerium oxide fine particles, inorganic fine particles such as carbon black, acrylic resin such as polycarbonate and polymethyl methacrylate, and polymer fine particles such as silicone resin. Among these, polymer fine particles and hydrophobic silica are preferable, and hydrophobic silica is more preferable.
When the surface treatment of toner particles is performed using an external additive, the amount of the external additive added is preferably 1 to 10 parts by weight, more preferably 100 parts by weight of the toner particles before the treatment with the external additive. 2 to 8 parts by weight, more preferably 3 to 6 parts by weight.
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, endothermic maximum peak temperature, melting point and glass transition point, crystallinity index]
(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 having a diameter of 1 mm and a length of 1 mm. The amount of flow tester drop by the flow tester was plotted against the temperature, and the temperature at which half the sample flowed out was taken as the softening point.
(2) Maximum peak temperature of endotherm, melting point and glass transition point The temperature was raised to 200 ° C. using a differential scanning calorimeter (manufactured by Parkin Elmer, trade name: Pyris 6 DSC), and the temperature lowering rate was 50 ° C./min. The sample cooled to 0 ° C. was 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 peak temperature. 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, and when a step is observed without a peak being observed, the tangent indicating the maximum slope of the curve of the step and the step The glass transition point was defined as the temperature at the intersection with the base line extension line on the high temperature side.
(3) Crystallinity index The crystallinity index was calculated from the softening point measured in (1) and the endothermic maximum peak temperature determined in (2).
Crystallinity index = (softening point (° C)) / (maximum endothermic peak temperature (° C))

[Glass transition point of resin particles]
First, the solvent was removed from the resin particle dispersion by freeze-drying to obtain a solid.
The lyophilization of the resin particle dispersion was carried out using a freeze dryer (manufactured by Tokyo Rika Kikai Co., Ltd., trade names: FDU-2100 and DRC-1000) with 30 g of the resin particle dispersion at −25 ° C. for 1 hour, Vacuum drying was performed at 10 ° C. for 10 hours and at 25 ° C. for 4 hours, and the moisture content was dried to 1% by weight or less. The moisture content was determined by using an infrared moisture meter (trade name: FD-230, manufactured by Kett Scientific Laboratory), drying sample 5 g, drying temperature 150 ° C. and measurement mode 96 (monitoring time 2.5 minutes / The fluctuation range was 0.05%).
About the solid substance obtained after solvent removal, the glass transition point of the resin particle was measured by the method similar to the measuring method of the glass transition point of the above-mentioned polyester.

[Number average molecular weight of polyester]
The molecular weight distribution was measured by gel permeation chromatography and the number average molecular weight was calculated by the following method.
(1) Preparation of sample solution Polyester was dissolved in chloroform so that the concentration was 0.5 g / 100 ml. Subsequently, this solution was filtered using a fluororesin filter having a pore size of 2 μm (manufactured by Sumitomo Electric Industries, Ltd., trade name: FP-200) to remove insoluble components to obtain a sample solution.
(2) Molecular weight distribution measurement Chloroform was allowed to flow as a lysis solution at a flow rate of 1 ml / min, and the column was stabilized in a constant temperature bath at 40 ° C. 200 μl of the sample solution was injected there for measurement. The molecular weight of the sample was calculated based on a calibration curve prepared in advance. The calibration curve at this time includes several types of monodisperse polystyrene (monodisperse polystyrene manufactured by Tosoh Corporation; molecular weights 1.11 × 10 ⁶ , 3.97 × 10 ⁵ , 1.89 × 10 ⁵ , 9.89 × 10 ⁴ , 1.71 × 10 ⁴ , 9.49 × 10 ³ , 5.87 × 10 ³ , 1.01 × 10 ³ , 5.00 × 10 ² ) were used as standard samples.
Measuring apparatus: HPLC LC-9130NEXT (manufactured by Nippon Analytical Industrial Co., Ltd., trade name)
Analytical column: JAIGEL-2.5-HA + JAIGEL-MH-A (manufactured by Nippon Analytical Industrial Co., Ltd., both trade names)

[Volume Median Particle Size (D ₅₀ ) and Particle Size Distribution of Colored Particles, Resin Particles, and 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 temperature at which the absorbance falls within an appropriate range. The CV value was calculated according to the following formula.
CV value (%) = (standard deviation of particle size distribution / volume median particle size (D ₅₀ )) × 100

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

[Volume Median Particle Size (D ₅₀ ) and Particle Size Distribution of Toner (Particle), Core Particle, Core Shell Particle]
The volume median particle size of the toner (particles) was measured as follows.
-Measuring machine: Coulter Multisizer III (Beckman Coulter, trade name)
・ Aperture diameter: 50μm
・ Analysis software: Multisizer III version 3.51 (Beckman Coulter, product name)
Electrolyte: Isoton II (Beckman Coulter, product name)
-Dispersion: Polyoxyethylene lauryl ether (trade name: Emulgen 109P, HLB: 13.6) manufactured by Kao Corporation was dissolved in the electrolytic solution to obtain a dispersion having a concentration of 5% by weight.
-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, and then 25 mL of electrolyte is added, and further dispersed for 1 minute with an ultrasonic disperser. A sample dispersion was prepared.
Measurement conditions: The sample dispersion is added to 100 mL of the electrolytic solution to adjust the particle size of 30,000 particles to a concentration that can be measured in 20 seconds, and then 30,000 particles are measured and the particle size distribution thereof. From this, the volume median particle size (D ₅₀ ) was determined.
The CV value (%) was calculated according to the following formula.
CV value (%) = (standard deviation of particle size distribution / volume median particle size (D ₅₀ )) × 100
The volume-median particle size of the core particles and the core-shell particles was measured in the same manner by using the core particle dispersion and the core-shell particle dispersion as the sample dispersion in the measurement of the volume-median particle size of the toner (particles).

[Core shell particle, toner circularity]
-Preparation of dispersion: The dispersion of the core-shell particles was diluted with deionized water so that the solid content concentration of the core-shell particles was 0.001 to 0.05% by weight as the sample dispersion. The toner dispersion was prepared by adding 50 mg of toner to 5 ml of 5 wt% polyoxyethylene lauryl ether (Emulgen 109P) aqueous solution, dispersing for 1 minute with an ultrasonic disperser, adding 20 ml of distilled water, A toner dispersion was obtained by dispersing for 1 minute using an ultrasonic disperser.
Measurement device: Flow-type particle image analyzer (manufactured by Sysmex Corporation, trade name: FPIA-3000)
・ Measurement mode: HPF measurement mode

[BET specific surface area of toner particles]
The BET specific surface area was measured under the following conditions using Micromeritics FlowSorbIII (manufactured by Shimadzu Corporation, trade name).
Toner sample amount: 0.09 to 0.11 g
・ Deaeration condition: 40 ° C., 10 minutes ・ Adsorption gas: Nitrogen gas

[Evaluation of low-temperature fixability of toner]
Using high-quality paper (Fuji Xerox Co., Ltd., J paper A4 size) with a commercially available printer (Oki Data Co., Ltd., trade name: ML5400), the toner adhesion amount on the paper is 0.42 to 0.48 mg / cm. ^A solid image of 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 temperature of the fixing device was set to 100 ° C., and fixing was performed at a speed of 1.5 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. Thirty sheets of high-quality paper (Oki Data Co., Ltd., Excellent White Paper A4 size) are laid under the printed material before and after the tape is applied, and the reflection image density of the fixed image portion before and after the tape is applied to each printed material. Measurement was carried out using a colorimeter (Gretag-Macbeth, trade name: SpectroEye, light emission condition: standard light source D ₅₀ , observation field of view 2 °, density reference DINNB, absolute white reference), and the fixing ratio was calculated from the following formula. Was calculated.
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.

[Evaluation of storage stability of toner]
10 g of toner was placed in a 20 ml internal volume plastic bottle and allowed to stand for 8 hours in an open state in an environment of a temperature of 53 ° C. and a relative humidity of 40 RH%. After standing, place three sieves in the order of 250 μm for the upper stage, 150 μm for the middle stage, and 75 μm for the lower stage on the shaking table of a powder tester (made by Hosokawa Micron Corporation), and put 2 g of toner on it. Vibrating for 60 seconds, the weight of toner remaining on each sieve was measured. The measured toner weight was applied to the following equation to calculate the degree of aggregation [%].
Aggregation degree [%] = a + b + c
a = (weight of residual toner on upper stage) / 2 [g] × 100
b = (middle stage residual toner weight) / 2 [g] × 100 × (3/5)
c = (lower stage residual toner weight) / 2 [g] × 100 × (1/5)
The storage stability of the toner was evaluated according to the following criteria. The smaller the degree of aggregation, the better the storage stability of the toner.

[Toner scattering]
A 20 ml cylindrical polypropylene bottle containing 0.7 g of toner and 9.3 g of a silicone ferrite carrier (trade name, average particle size: 40 μm, manufactured by Kanto Denka Kogyo Co., Ltd.) in an environment with a room temperature of 25 ° C. and a relative humidity of 50%. (Nikko Co., Ltd.) and shaken 10 times vertically and horizontally. Then, it stirred for 10 minutes with the ball mill. A developing roller (diameter 42 mm) mounted on a commercially available printer was taken out and modified to be variable in rotation (external developing roller device). The current roller of the external developing roller device was rotated at a speed of 10 revolutions / minute, and the developer was deposited on the developing roller so as to have a width of 3 to 8 cm. After uniformly attaching, the rotation was once stopped. The rotation number of the developing roller was changed to 45 rotations / minute, and the number of scattered toner particles when rotated for 1 minute was measured with DIGITAL DUST INDICATOR MODEL P-5 (manufactured by SIBATA SCIENTIFIC TECHNOLOGY LTD, trade name).
The toner scattering property was evaluated from the number of scattered toner particles. The scattering property indicates that the smaller the toner scattering particle number, the better.

Production Example 1
(Production of crystalline polyester a)
The inside of a four-necked flask equipped with a nitrogen introduction tube, a dehydration tube, a stirrer, and a thermocouple was purged with nitrogen, and 3936 g of 1,9-nonanediol and 4848 g of sebacic acid were added. While stirring, the temperature was raised to 140 ° C., maintained at 140 ° C. for 3 hours, and then heated from 140 ° C. to 200 ° C. over 10 hours. Thereafter, 50 g of tin dioctylate was added, and the mixture was further maintained at 200 ° C. for 1 hour, and then the pressure in the flask was lowered and maintained at 8.0 kPa for 4 hours to obtain crystalline polyester a. Table 1 shows the softening point, melting point, crystallinity index, number average molecular weight and acid value of the obtained crystalline polyester a.

Production Example 2
(Production of crystalline polyester b)
The inside of a four-necked flask equipped with a nitrogen introduction tube, a dehydration tube, a stirrer, and a thermocouple was purged with nitrogen, and 2419 g of 1,6-hexanediol and 4957 g of 1,12-dodecanedioic acid were added. While stirring, the temperature was raised to 140 ° C., maintained at 140 ° C. for 3 hours, and then heated from 140 ° C. to 200 ° C. over 10 hours. Thereafter, 30 g of tin dioctylate was added and the mixture was further maintained at 200 ° C. for 1 hour, and then the pressure in the flask was lowered and maintained at 8.0 kPa for 4 hours to obtain crystalline polyester b. Table 1 shows the softening point, melting point, crystallinity index, number average molecular weight and acid value of the obtained crystalline polyester b.

Production Example 3
(Production of amorphous polyester a)
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, 4931 g of polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, 808 g of polyoxyethylene (2.0) -2,2-bis (4-hydroxyphenyl) propane, 1279 g of terephthalic acid and 40 g of tin dioctylate were added, and the temperature was raised to 235 ° C. with stirring in a nitrogen atmosphere. After maintaining the time, the pressure in the flask was further lowered and maintained at 8.0 kPa for 1 hour. After returning to atmospheric pressure, the mixture was cooled to 190 ° C., 711 g of fumaric acid and 1.5 g of tert-butylcatechol were added, maintained at 190 ° C. for 1 hour, and then heated to 210 ° C. over 4 hours. Further, the pressure in the flask was lowered and maintained at 8.0 kPa for 1 hour. After returning to atmospheric pressure, 271 g of trimellitic anhydride was added and maintained at 210 ° C. for 1 hour, then the pressure in the flask was further reduced and maintained at 8.0 kPa for 2 hours to obtain amorphous polyester a. It was. Table 1 shows the softening point, glass transition point, crystallinity index, number average molecular weight and acid value of the obtained amorphous polyester a.

Production Example 4
(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 5900 g of polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, 1301 g of terephthalic acid and 41 g of tin dioctylate were added, and the temperature was raised to 235 ° C. with stirring in a nitrogen atmosphere and maintained for 8 hours. Then, the pressure in the flask was further lowered and maintained at 8.0 kPa for 1 hour. After returning to atmospheric pressure, the mixture was cooled to 190 ° C., 724 g of fumaric acid and 1.5 g of tert-butylcatechol were added, maintained at 190 ° C. for 1 hour, and then heated to 210 ° C. over 4 hours. Further, the pressure in the flask was lowered and maintained at 8.0 kPa for 1 hour. After returning to atmospheric pressure, 275 g of trimellitic anhydride was added and maintained at 210 ° C. for 1 hour, then the pressure in the flask was further reduced and maintained at 8.0 kPa for 2 hours to obtain amorphous polyester b. It was. Table 1 shows the softening point, glass transition point, crystallinity index, number average molecular weight, and acid value of the obtained amorphous polyester b.

Production Example 5
(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 4246 g of polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, 1690 g of polyoxyethylene (2.0) -2,2-bis (4-hydroxyphenyl) propane, 1338 g of terephthalic acid and 42 g of tin dioctylate were added, and the temperature was raised to 235 ° C. with stirring in a nitrogen atmosphere. After maintaining the time, the pressure in the flask was further lowered and maintained at 8.0 kPa for 1 hour. After returning to atmospheric pressure, the mixture was cooled to 190 ° C., 744 g of fumaric acid and 1.5 g of tert-butylcatechol were added, maintained at 190 ° C. for 1 hour, and then heated to 210 ° C. over 4 hours. Further, the pressure in the flask was lowered and maintained at 8.0 kPa for 1 hour. After returning to atmospheric pressure, 283 g of trimellitic anhydride was added and maintained at 210 ° C. for 1 hour, then the pressure in the flask was further lowered and maintained at 8.0 kPa for 2 hours to obtain amorphous polyester c. It was. Table 1 shows the softening point, glass transition point, crystallinity index, number average molecular weight, and acid value of the obtained amorphous polyester c.

Production Example 6
(Production of amorphous polyester d)
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 3322 g of polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, Polyoxyethylene (2.0) -2,2-bis (4-hydroxyphenyl) propane (31 g), terephthalic acid (662 g) and dibutyltin oxide (10 g) were added and the temperature was raised to 230 ° C. with stirring in a nitrogen atmosphere for 5 hours. After the maintenance, the pressure in the flask was further lowered and maintained at 8.0 kPa for 1 hour. After returning to atmospheric pressure, the mixture was cooled to 190 ° C., 685 g of fumaric acid and 0.49 g of tert-butylcatechol were added, maintained at 190 ° C. for 1 hour, and then heated to 210 ° C. over 2 hours. Further, the pressure in the flask was lowered and maintained at 8.0 kPa for 4 hours to obtain amorphous polyester d. Table 1 shows the softening point, glass transition point, crystallinity index, number average molecular weight and acid value of the obtained amorphous polyester d.

Production Example 7
(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 903 g of polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, Put 4751 g of polyoxyethylene (2.0) -2,2-bis (4-hydroxyphenyl) propane, 1328 g of terephthalic acid and 40 g of tin dioctylate, and raise the temperature to 235 ° C. with stirring in a nitrogen atmosphere. After maintaining the time, the pressure in the flask was further lowered and maintained at 8.0 kPa for 1 hour. After returning to atmospheric pressure, the mixture was cooled to 190 ° C., 738 g of fumaric acid and 1.5 g of tert-butylcatechol were added, maintained at 190 ° C. for 1 hour, and then heated to 210 ° C. over 4 hours. Further, the pressure in the flask was lowered and maintained at 8.0 kPa for 1 hour. After returning to atmospheric pressure, 281 g of trimellitic anhydride was added and maintained at 210 ° C. for 1 hour, then the pressure in the flask was further reduced and maintained at 8.0 kPa for 2 hours to obtain amorphous polyester e. It was. Table 1 shows the softening point, glass transition point, crystallinity index, number average molecular weight and acid value of the obtained amorphous polyester e.

Production Example 8
(Production of amorphous polyester f)
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 5635 g of polyoxyethylene (2.0) -2,2-bis (4-hydroxyphenyl) propane, 1338 g of terephthalic acid and 40 g of tin dioctylate were added, and the temperature was raised to 235 ° C. with stirring in a nitrogen atmosphere and maintained for 5 hours. Then, the pressure in the flask was further lowered and maintained at 8.0 kPa for 1 hour. After returning to atmospheric pressure, the mixture was cooled to 190 ° C., 744 g of fumaric acid and 1.5 g of tert-butylcatechol were added, maintained at 190 ° C. for 1 hour, and then heated to 210 ° C. over 4 hours. Further, the pressure in the flask was lowered and maintained at 8.0 kPa for 1 hour. After returning to atmospheric pressure, 283 g of trimellitic anhydride was added and maintained at 210 ° C. for 1 hour, and then the pressure in the flask was further reduced and maintained at 8.0 kPa for 2 hours to obtain amorphous polyester f. It was. Table 1 shows the softening point, glass transition point, crystallinity index, number average molecular weight, and acid value of the obtained amorphous polyester f.

Production Example 9
(Production of amorphous polyester g)
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 1791 g of polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, Put 3881 g of polyoxyethylene (2.0) -2,2-bis (4-hydroxyphenyl) propane, 1317 g of terephthalic acid, and 40 g of tin dioctylate, and raise the temperature to 235 ° C. with stirring in a nitrogen atmosphere. After maintaining the time, the pressure in the flask was further lowered and maintained at 8.0 kPa for 1 hour. After returning to atmospheric pressure, the mixture was cooled to 190 ° C., 732 g of fumaric acid and 1.5 g of tert-butylcatechol were added, maintained at 190 ° C. for 1 hour, and then heated to 210 ° C. over 4 hours. Further, the pressure in the flask was lowered and maintained at 8.0 kPa for 1 hour. After returning to atmospheric pressure, 278 g of trimellitic anhydride was added and maintained at 210 ° C. for 1 hour, then the pressure in the flask was further lowered and maintained at 8.0 kPa for 2 hours to obtain amorphous polyester g. It was. Table 1 shows the softening point, glass transition point, crystallinity index, number average molecular weight and acid value of the obtained amorphous polyester g.

Production Example 10
(Preparation of resin particle (A) dispersion 1 (step (1)))
In a flask equipped with a stirrer, crystalline polyester a 90 g, amorphous polyester a 510 g, copper phthalocyanine pigment (manufactured by Dainichi Seika Kogyo Co., Ltd., trade name: ECB301), polyoxyethylene alkyl ether (manufactured by Kao Corporation) Nonionic surfactant, trade name: Emulgen 150) 8.5 g, 15% by weight sodium dodecylbenzenesulfonate aqueous solution (manufactured by Kao Corporation, anionic surfactant, trade name: Neoperex G-15) 80 g, While stirring, 250 g of 5 wt% aqueous potassium hydroxide solution was added, the mixture was heated to 98 ° C. and melted, and mixed at 98 ° C. for 2 hours to obtain a resin mixture.
Next, 1032 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.
The obtained resin particle dispersion was heated to 55 ° C. at a heating rate of 0.5 ° C./min and then held at 55 ° C. for 5 hours. Thereafter, the mixture was cooled to room temperature (25 ° C.) at an average rate of 10 ° C./min to obtain resin particle (A) dispersion 1. Table 2 shows the solid content concentration, volume median particle size, and CV value of the obtained dispersion.

Production Example 11
(Preparation of resin particle (A) dispersion 2 (step (1)))
In Production Example 10, except that amorphous polyester a was changed to amorphous polyester b, the amount of 5 wt% potassium hydroxide aqueous solution was changed to 230 g, and the amount of deionized water added was changed to 1051 g, respectively. In the same manner, a resin particle (A) dispersion 2 was obtained. Table 2 shows the solid content concentration, volume median particle size, and CV value of the obtained dispersion.

Production Example 12
(Preparation of resin particle (A) dispersion 3 (step (1)))
In Production Example 10, 590 g of amorphous polyester a was changed to 210 g of amorphous polyester b and 300 g of amorphous polyester d, the amount of 5% by weight potassium hydroxide aqueous solution was changed to 262 g, and the amount of deionized water added was Resin particle dispersion 3 was obtained in the same manner as in Production Example 10, except that the amount was changed to 1022 g. Table 2 shows the solid content concentration, volume median particle size, and CV value of the obtained dispersion.

Production Example 13
(Preparation of resin particle (A) dispersion 4 (step (1)))
In Production Example 10, crystalline polyester a is crystalline polyester b, amorphous polyester a is amorphous polyester b, the amount of 5 wt% potassium hydroxide aqueous solution is 238 g, and the amount of deionized water added is A resin particle dispersion 4 was obtained in the same manner as in Production Example 10, except that the amount was changed to 1044 g. Table 2 shows the solid content concentration, volume median particle size, and CV value of the obtained dispersion.

Production Example 14
(Preparation of resin particle (A) dispersion 5 (step (1)))
In Production Example 10, Production Example 10 was changed except that amorphous polyester a was changed to amorphous polyester e, the amount of 5 wt% potassium hydroxide aqueous solution was changed to 275 g, and the amount of deionized water added was changed to 1009 g. In the same manner as above, a resin particle dispersion 5 was obtained. Table 2 shows the solid content concentration, volume median particle size, and CV value of the obtained dispersion.

Production Example 15
(Preparation of Resin Particle (A) Dispersion 6 (Step (1)))
In Production Example 10, except that amorphous polyester a was changed to amorphous polyester f, the amount of 5 wt% aqueous potassium hydroxide solution was changed to 251 g, and the amount of deionized water added was changed to 1031 g, respectively. In the same manner as above, a resin particle dispersion 6 was obtained. Table 2 shows the solid content concentration, volume median particle size, and CV value of the obtained dispersion.

Production Example 16
(Preparation of resin particle (A) dispersion 7 (step (1)))
In Production Example 10, Production Example 10 was changed except that amorphous polyester a was changed to amorphous polyester c, the amount of 5 wt% potassium hydroxide aqueous solution was changed to 247 g, and the amount of deionized water added was changed to 1035 g. In the same manner as above, a resin particle dispersion 7 was obtained. Table 2 shows the solid content concentration, volume median particle size, and CV value of the obtained dispersion.

Production Example 17
(Preparation of resin particle (C) dispersion 8)
In a flask having an internal volume of 5 liters, 600 g of amorphous polyester e, 6 g of polyoxyethylene alkyl ether (manufactured by Kao Corporation, nonionic surfactant, trade name: Emulgen 430), 15% by weight sodium dodecylbenzenesulfonate aqueous solution (Kao Co., Ltd., trade name: Neoperex G-15) 40 g and 5 wt% aqueous potassium hydroxide solution 281 g were added, heated to 95 ° C. with stirring, melted, and mixed at 95 ° C. for 2 hours. A resin mixture was obtained.
Next, 1003 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 25% by weight, and a resin particle dispersion 8 was obtained. Table 3 shows the volume-median particle size and CV value of the obtained dispersion.

Production Example 18
(Preparation of resin particle (C) dispersion 9)
In Production Example 17, Production Example 17 except that amorphous polyester e was changed to amorphous polyester f, the amount of 5 wt% potassium hydroxide aqueous solution was changed to 253 g, and the amount of deionized water dropped was changed to 1029 g. In the same manner, a resin particle dispersion 9 was obtained. Table 3 shows the volume-median particle size and CV value of the obtained dispersion.

Production Example 19
(Preparation of resin particle (C) dispersion 10)
In Production Example 17, Production Example 17 was changed except that amorphous polyester e was changed to amorphous polyester b, the amount of 5 wt% potassium hydroxide aqueous solution was changed to 228 g, and the amount of deionized water dropped was changed to 1053 g. In the same manner, a resin particle dispersion 10 was obtained. Table 3 shows the volume-median particle size and CV value of the obtained dispersion.

Production Example 20
(Preparation of resin particle (C) dispersion 11)
In Production Example 17, Production Example 17 except that amorphous polyester e was changed to amorphous polyester g, the amount of 5 wt% potassium hydroxide aqueous solution was changed to 244 g, and the amount of deionized water dropped was changed to 1038 g. In the same manner as above, a resin particle dispersion 11 was obtained. Table 3 shows the volume-median particle size and CV value of the obtained dispersion.

Production Example 21
(Production of release agent particle dispersion)
In a beaker with an internal volume of 1 liter, 480 g of deionized water, alkenyl (mixture of hexadecenyl group and octadecenyl group) dipotassium succinate aqueous solution (trade name: Latemul ASK, effective concentration 28 wt%) 4.29 g, carnauba wax 120 g of wax (manufactured by Hiroyuki Kato, trade name, melting point 85 ° C., acid value 5 mg KOH / g) was added and stirred. While maintaining the mixed liquid at 90 to 95 ° C., using an ultrasonic disperser (trade name: Ultrasonic Homogenizer 600W, manufactured by Nippon Seiki Seisakusho Co., Ltd.), the mixture was subjected to a dispersion treatment for 30 minutes and then cooled to 25 ° C. Then, deionized water was added to adjust the solid content to 20% by weight to obtain a release agent particle dispersion. The volume median particle size of the release agent particles was 0.494 μm, and the CV value was 34%.

Example 1
(Preparation of Toner A)
<Step (2): Production of aggregated particles>
500 g of resin particle dispersion, 140 g of deionized water, and 84 g of release agent particle dispersion were placed in a 5-liter four-necked flask equipped with a dehydration tube, a stirrer, and a thermocouple, and mixed at 25 ° C. . Next, while stirring the mixture, an aqueous flocculant solution in which 42 g of ammonium sulfate was dissolved in 475 g of deionized water was added dropwise at 25 ° C. over 10 minutes, and then the temperature was raised to 55 ° C. Until the diameter reached 4.3 μm, the temperature was maintained at 55 ° C. to obtain aggregated particles.
<Step (3): Preparation of core-shell particles>
61 g of deionized water was added to the core aggregated particle dispersion obtained in step (2), and the temperature of the core aggregated particle dispersion was cooled to 49 ° C. Next, while the temperature of the 49 ° C. dispersion was raised at a rate of 1.6 ° C./hr, 315 g of the resin particle dispersion 8 was dropped at a rate of 1.0 ml / min to obtain a core-shell aggregated particle dispersion.
<Step (4): Production of united core-shell particles>
37 g of an anionic surfactant (trade name: EMAL (registered trademark) E27C, effective concentration 27 wt%) manufactured by Kao Corporation, and 3,000 g of deionized water were added to the core-shell aggregated particle dispersion obtained in step (3). The mixed aqueous solution was added, and the temperature was raised to 67 ° C., and then kept for 1 hour.
<Post-processing step: preparation of toner>
Next, the dispersion was cooled to 25 ° C., and the solid content was separated by suction filtration while being kept at 25 ° C., then washed with deionized water, and dried at 33 ° C. to obtain toner particles. 100 parts by weight of the toner particles, 2.5 parts by weight 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 diameter: 0.012 μm) 1.0 part by weight was put in a Henschel mixer, stirred, and passed through a 150-mesh sieve to obtain toner A. Table 4 shows the volume-median particle size, CV value, and toner performance evaluation results of the obtained toner A.

Examples 2 to 4 and Comparative Examples 1 to 4 (Production of Toners B to H)
Except for using the dispersion shown in Tables 4 and 5 as the resin particle dispersion used in the step (2) and using the dispersion shown in Tables 4 and 5 as the resin particle dispersion dropped in the step (3). In the same manner as in Example 1, toners B to H were prepared. Tables 4 and 5 show the volume-median particle diameters, CV values, and toner performance evaluation results of the obtained toners B to H.

  From Tables 4 and 5, the electrophotographic toners of the examples obtained by the method for producing the electrophotographic toner of the present invention have a sharp particle size distribution, low temperature fixability and storage stability as compared with the comparative toners. It can be seen that both of the above can be achieved and toner scattering can be suppressed.

Claims (9)

A method for producing a core-shell type electrophotographic toner, comprising the following steps (1) to (4).
Step (1): Amorphous polyester (b) obtained by polycondensation of crystalline polyester (a) and an alcohol component containing 80 mol% or more of a propylene oxide adduct of bisphenol A and a carboxylic acid component , content by mixing while melting in 80% or more by weight of an aqueous medium, phase inversion emulsified in the aqueous medium, the process to obtain resin particles (a) (2): aggregated resin particles (a) Step (3): Amorphous particles obtained by polycondensing an alcohol component containing 80 mol% or more of an ethylene oxide adduct of bisphenol A and a carboxylic acid component into the dispersion of the aggregated particles. The step of adding the resin particles (C) containing the modified polyester (c) to obtain the core-shell particles Step (4): The temperature of the system containing the core-shell particles is changed to that of the amorphous polyester (c). Holding than glass transition point 5 ° C. lower temperature or higher, to obtain a combined core-shell particles   The method for producing an electrophotographic toner according to claim 1, wherein in step (4), the temperature of the system containing the core-shell particles is maintained at a temperature not higher than the melting point of the crystalline polyester (a).   In the step (1), before the step (2), the aqueous dispersion containing the resin particles (A) obtained in the step (1) is converted to a temperature below the melting point of the crystalline polyester (a) and the crystalline polyester (a). The method for producing an electrophotographic toner according to claim 1, further comprising a step of holding at a temperature of 25 ° C. or more lower than the melting point of the toner for 1 hour or more.   The manufacturing method of the toner for electrophotography in any one of Claims 1-3 whose melting | fusing point of crystalline polyester (a) is 60-100 degreeC.   The method for producing an electrophotographic toner according to claim 1, wherein the resin particles (A) contain a colorant.   The method for producing an electrophotographic toner according to claim 1, wherein the carboxylic acid component of the amorphous polyester (b) and the amorphous polyester (c) contains fumaric acid.   The method for producing an electrophotographic toner according to any one of claims 1 to 6, wherein the amorphous polyester (c) is an amorphous polyester having a glass transition point of 55 to 75 ° C.   The alcohol component of the amorphous polyester (b) contains an ethylene oxide adduct of bisphenol A, and the alcohol component of the amorphous polyester (c) contains a propylene oxide adduct of bisphenol A. The method for producing an electrophotographic toner according to any one of the above.   An electrophotographic toner obtained by the production method according to claim 1.