JP2023088255A - Toner for electrostatic charge image development - Google Patents

Abstract

To provide a toner for electrostatic charge image development which is excellent in durability, and a method for manufacturing the same.SOLUTION: There is provided a core-shell type toner for electrostatic charge image development, wherein the core contains a composite resin including a polyester resin segment Pc, a styrenic resin segment, and a bireactive monomer-derived structural unit for coupling the polyester resin segment Pc and the styrenic resin segment through a covalent bond; the shell contains a polyester-based resin containing a polyester resin segment Ps; and at least any one of the polyester resin segment Pc and the polyester resin segment Ps is a polycondensate of an alcohol component, a carboxylic acid component and recycled polyethylene terephthalate.SELECTED DRAWING: None

Description

The present invention relates to an electrostatic charge image developing toner used for developing a latent image formed by an electrophotography method, an electrostatic recording method, an electrostatic printing method, or the like, and a method for producing the same.

In the field of electrophotography, with the development of electrophotographic systems, there is a demand for developing toners for developing electrostatic images that are capable of achieving even higher image quality. For example, core-shell type toners are being studied.

On the other hand, the use of polyethylene terephthalate (PET) as a raw material for the binder resin is being studied because it is possible to control the compatibility between the core and the shell. From this point of view, the use of recycled PET is desired.

Patent Document 1 describes the following steps (1) to (4):
Step (1): Mix the crystalline resin (B) and the amorphous composite resin (A) in the presence of a basic compound to obtain a resin mixture Step (2): Add an aqueous medium to the obtained resin mixture is added to perform phase inversion emulsification to obtain an aqueous dispersion of resin particles (I). Obtaining Step (4): A method for producing a toner for developing an electrostatic charge image, comprising a step of fusing the aggregated particles in the aqueous dispersion of the aggregated particles to obtain an aqueous dispersion of the fused particles. The crystalline composite resin (A) contains a polyester resin segment (a1) and a vinyl resin segment (a2) containing a structural unit derived from a vinyl monomer having a hydrocarbon group having 6 or more and 22 or less carbon atoms. A method of making toner for image development is disclosed.

Patent Document 2 discloses a polyester resin which is a polycondensation product of a raw material containing a polyhydric carboxylic acid component and a polyhydric alcohol component, wherein the polyhydric alcohol component contains erucic acid dimer diol. an amorphous polyester resin, wherein the raw material comprises at least one compound selected from the group consisting of polyethylene terephthalate, polybutylene terephthalate, depolymerization of polyethylene terephthalate, and depolymerization of polybutylene terephthalate; disclosed.

Patent Document 3 discloses a method for producing a toner including the following steps 1 to 5, wherein the difference [AB] between the following B and the following A is 20 mol % or more. is disclosed.
Step 1: A step of reacting an alcohol component, a carboxylic acid component, and polyethylene terephthalate to obtain a core resin (a).
Step 2: A step of obtaining a shell resin (b) through reaction of an alcohol component, a carboxylic acid component, and optionally polyethylene terephthalate.
Step 3: A step of obtaining aggregated particles (I) from an aqueous dispersion containing a core resin (a) and a release agent.
Step 4: A step of adding shell resin (b) to aggregated particles (I) obtained in step 3 to obtain a dispersion of aggregated particles (II).
Step 5: A step of fusing the aggregated particles (II) obtained in Step 4 to obtain core-shell particles.
A: A (mol %) is the amount of polyethylene terephthalate blended in terms of the molar ratio of the ethylene glycol units of polyethylene terephthalate to the sum of the number of moles of the alcohol component in step 1 and the number of moles of the ethylene glycol units of polyethylene terephthalate. and
B: B (mol %) is the amount of polyethylene terephthalate blended in terms of the molar ratio of the ethylene glycol units of polyethylene terephthalate to the sum of the number of moles of the alcohol component in step 2 and the number of moles of the ethylene glycol units of polyethylene terephthalate. and

Patent Document 4 discloses a recycled polyester resin having an alkylene terephthalate structure as a structural unit, containing a depolymerization catalyst, and containing 1,1,1,3,3,3-hexafluoro-2-propanol ( HFIP) has disclosed a polyester resin for electrostatic charge image developing toners characterized by having an insoluble content of 1 to 30% by weight.

JP 2018-18069 A JP 2019-99699 A JP 2017-173507 A JP 2009-192856 A

However, when PET is used as a raw material for the binder resin, durability tends to decrease.

TECHNICAL FIELD The present invention relates to an electrostatic charge image developing toner excellent in durability and a method for producing the same.

The present invention
[1] A core-shell type electrostatic image developing toner, wherein the core comprises a polyester resin segment Pc, a styrene resin segment, and the polyester resin segment Pc and the styrene resin segment via covalent bonds. containing a composite resin containing a structural unit derived from a bi-reactive monomer to be bonded, the shell containing a polyester resin containing a polyester resin segment Ps, and at least one of the polyester resin segment Pc and the polyester resin segment Ps is a polycondensate of an alcohol component, a carboxylic acid component and a recycled polyethylene terephthalate, and [2] Step 1: Aggregate core resin particles containing core resin in an aqueous medium to obtain aggregated particles (I);
Step 2: a step of aggregating shell resin particles containing a shell resin on the surface of the aggregated particles (I) obtained in step 1 to obtain aggregated particles (II); A method for producing a toner for developing an electrostatic charge image, comprising a step of fusing aggregated particles (II) thus obtained to obtain core-shell particles, wherein the core resin comprises a polyester resin segment Pc and a styrene resin segment and a structural unit derived from a bi-reactive monomer that bonds the polyester resin segment Pc and the styrenic resin segment via a covalent bond, and the shell resin contains the polyester resin segment Ps. Production of a toner for electrostatic charge image development containing a polyester resin, wherein at least one of the polyester resin segment Pc and the polyester resin segment Ps is a polycondensate of an alcohol component, a carboxylic acid component, and recycled polyethylene terephthalate. Regarding the method.

The electrostatic charge image developing toner of the present invention exhibits an excellent effect in terms of durability.

The electrostatic charge image developing toner of the present invention is a core-shell type toner, and is significant in that the polyester resin segment contained in at least one of the core and the shell is obtained using recycled polyethylene terephthalate (recycled PET). Although the details are unknown, it is presumed that the effects of the present invention are achieved by the following mechanism.

In the polycondensation reaction of PET, an alcohol component, and a carboxylic acid component, PET is incorporated into the polyester resin chain by transesterification while undergoing depolymerization. considered to exist as a unit. When this PET component and other polyester segments form a heterogeneous interface, the toner tends to be broken from this interface. Therefore, it is presumed that the use of PET as a raw material generally reduces the durability of the toner.
On the other hand, PET contains a small amount of metal components derived from a catalyst or the like during production, and it is believed that local aggregation occurs in polyester segments with those metals serving as nuclei. The strength of this cohesive force varies depending on the type of metal, but in the present invention, by using recycled PET in which a large number of metals are mixed in during the recycling process, unlike the case of using new PET (Virgin PET), polyester The distribution of the aggregation state of the segments widens corresponding to the existence of various metal species, stress dispersion occurs efficiently, and the breakage of the heterogeneous interface is alleviated, and the durability of the toner is improved. guessed.

In the toner of the present invention, the core comprises a polyester resin segment Pc, a styrene resin segment, and a structural unit derived from a bi-reactive monomer that bonds the polyester resin segment Pc and the styrene resin segment via a covalent bond. Contains a composite resin containing Since the composite resin is more hydrophobic than the polyester resin, it has good dispersibility of a hydrophobic material such as a mold release agent, and is excellent in durability.

The polyester resin segment Pc is a polycondensate of an alcohol component and a carboxylic acid component or a polycondensate of an alcohol component, a carboxylic acid component and regenerated polyethylene terephthalate.

As the alcohol component, from the viewpoint of low-temperature fixability, formula (I):

(Wherein, OR and RO are oxyalkylene groups, R is an ethylene group and/or propylene group, x and y represent the average number of added moles of alkylene oxide, each being a positive number, and x and y is 1 or more, preferably 1.5 or more, and 16 or less, preferably 8 or less, more preferably 6 or less, and still more preferably 4 or less)
A compound represented by is preferred. Examples of the alkylene oxide adduct of bisphenol A represented by formula (I) include a polyoxypropylene adduct of 2,2-bis(4-hydroxyphenyl)propane and a polyoxypropylene adduct of 2,2-bis(4-hydroxyphenyl)propane. polyoxyethylene adducts, and the like. It is preferable to use one or more of these.

The content of the alkylene oxide adduct of bisphenol A represented by formula (I) is preferably 5 mol% or more, more preferably 10 mol% or more, still more preferably 20 mol% or more, in the alcohol component, and , preferably 95 mol % or less, more preferably 80 mol % or less, still more preferably 70 mol % or less. When recycled PET is used, the alcohol component also includes ethylene glycol units contained in recycled PET, which will be described later.
When recycled PET is not used, the content of the alkylene oxide adduct of bisphenol A represented by formula (I) is preferably 70 mol% or more, more preferably 80 mol% or more, and even more preferably 80 mol% or more, in the alcohol component. is 90 mol % or more, more preferably 95 mol % or more, more preferably 100 mol %.

Other alcohol components include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,4-butene Aliphatic diols such as diols, 1,3-butanediol and neopentyl glycol, trivalent or higher alcohols such as glycerin, and the like.

The carboxylic acid component is preferably at least one selected from the group consisting of aromatic dicarboxylic acid compounds, aliphatic dicarboxylic acid compounds, and trivalent or higher carboxylic acid compounds. It is more preferable to contain an acid-based compound.

Examples of aromatic dicarboxylic acid compounds include phthalic acid, isophthalic acid, terephthalic acid, anhydrides of these acids, and alkyl esters having alkyl groups of 1 to 3 carbon atoms. Among these, terephthalic acid or isophthalic acid is preferred, and terephthalic acid is more preferred, from the viewpoint of low-temperature fixability.

The content of the aromatic dicarboxylic acid compound in the carboxylic acid component is preferably 40 mol% or more, more preferably 50 mol% or more, still more preferably 60 mol% or more, from the viewpoint of low-temperature fixability, and It is 100 mol % or less, preferably 90 mol % or less. When recycled PET is used, the carboxylic acid component includes terephthalic acid units contained in recycled PET, which will be described later.

Aliphatic dicarboxylic acid compounds include oxalic acid, malonic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, succinic acid optionally substituted with a hydrocarbon group having 1 to 20 carbon atoms, and adipine. Acids, aliphatic dicarboxylic acids such as sebacic acid, anhydrides of these acids, and alkyl esters in which the alkyl group has from 1 to 3 carbon atoms are included.

Trivalent or higher carboxylic acid compounds include 1,2,4-benzenetricarboxylic acid (trimellitic acid), 2,5,7-naphthalenetricarboxylic acid, pyromellitic acid, anhydrides of these acids, and alkyl groups. Examples thereof include alkyl esters having 1 to 3 carbon atoms, among which trimellitic acid compounds are preferred.

In this specification, macromonomers and hydroxycarboxylic acids are not included in alcohol components and carboxylic acid components.

A monohydric alcohol may be contained in the alcohol component, and a monohydric carboxylic acid compound may be contained in the carboxylic acid component, as appropriate.

In the present invention, recycled PET is obtained by collecting used PET and using it as a raw material. After removing, it is pulverized into flakes or the like. (1) The pulverized product can be used as it is, but after pulverization, for example, the following post-treatments may be applied.
(2) The pulverized material is kneaded and coarsely pulverized.
(3) Pulverized materials often contain foreign substances adhering to or mixed with them, and when ordinary washing cannot sufficiently remove chemical substances adsorbed on the surface of PET bottles, alkali washing is usually adopted. . When a portion of the pulverized product is hydrolyzed by alkali washing, it is preferable to melt the washed pulverized product, pelletize it, and then subject it to solid-phase polymerization in order to restore the degree of polymerization that has decreased. In the solid-state polymerization step, the washed flakes or the flakes melt-extruded and pelletized are continuously solid-phase polymerized in an inert gas such as nitrogen gas or rare gas at 180 to 245 ° C., preferably 200 to 240 ° C. It can be done by
(4) The washed pulverized material is depolymerized to decompose into monomer units and resynthesized.
Since the recycled PET in the present invention has a low IV value, it is preferably (1) (pulverized product) or (2) (kneaded and coarsely pulverized product).

Recycled PET contains a variety of metals. In other words, in the case of new PET, the number of metals contained is about three, including the metal components derived from the catalyst used at the time of manufacture. In addition to the metal species that are collected, at least metal species derived from water, cleaning agents, etc. used in the washing process after recovery are also mixed.

Therefore, from the viewpoint of contained metal species, a preferred embodiment of recycled PET is, for example,
Containing 5 or more metal species, preferably 5 or more and 20 or less,
In general, metal species that can be contained in catalysts used for PET production include, for example, antimony (Sb), cobalt (Co), manganese (Mn), and titanium (Ti). contains 3 or more, preferably 3 to 15 metal species,
Examples of metal species contained in water and detergents include sodium (Na), magnesium (Mg) and iron (Fe), so the total content of these metal species is 1 ppm or more, preferably 2 ppm or more and 300 ppm. Examples include the following.

The recycled PET reacts with the alcohol component and the carboxylic acid component in the polycondensation reaction and is incorporated into the structure of the resin. At this time, the recycled PET may be depolymerized.
Therefore, in the present invention, the recycled PET is preferably a recycled PET with a relatively low IV value, ie, a low molecular weight, compared to conventionally used PET. In the present invention, by introducing recycled PET having a low IV value (low molecular weight) into the polyester resin, depolymerization of the recycled PET proceeds more uniformly.

The IV value of the recycled PET is preferably 0.40 or more, more preferably 0.45 or more, still more preferably 0.50 or more, still more preferably 0.55 or more, and from the viewpoint of low-temperature fixability and uniform depolymerization, preferably 0.85. Below, it is more preferably 0.80 or less, still more preferably 0.75 or less, and still more preferably 0.70 or less. The IV value is an intrinsic viscosity and serves as an index of molecular weight. The IV value of the recycled PET can be adjusted by the polycondensation time or the like.

The content of the recycled PET having a low IV value is preferably 90% by mass or more, more preferably 95% by mass or more, still more preferably 98% by mass or more, and still more preferably 100% by mass in the total amount of the recycled PET subjected to polycondensation. % by mass.

The content of the recycled PET is preferably 5 mol% or more, more preferably 15 mol% or more, and still more preferably 30 mol% or more of the total amount of the alcohol component, the carboxylic acid component and the recycled PET, from the viewpoint of durability. Yes, and preferably 75 mol % or less, more preferably 60 mol % or less, still more preferably 50 mol % or less.
Since recycled PET is a polycondensation of ethylene glycol, terephthalic acid, dimethyl terephthalate, etc., the terephthalic acid-ethylene glycol unit (Mw: 192) is converted to 1 mol. Therefore, moles of PET=moles of ethylene glycol units=moles of terephthalic acid units.

The polycondensation reaction of the alcohol component and the carboxylic acid component, or the alcohol component, the carboxylic acid component and the recycled PET is carried out, for example, in an inert gas atmosphere, preferably in the presence of an esterification catalyst, and if necessary, an ester It can be carried out in the presence of a chemical promoter, a polymerization inhibitor, etc., preferably at a temperature of about 180° C. or higher and 250° C. or lower. Examples of the esterification catalyst include tin compounds such as dibutyltin oxide and tin(II) 2-ethylhexanoate, and titanium compounds such as titanium diisopropylate bistriethanolamine. Among these, tin compounds such as tin (II) 2-ethylhexanoate are preferred. The amount of the esterification catalyst used is preferably 0.01 parts by mass or more, more preferably 0.1 parts by mass or more, relative to 100 parts by mass of the raw material (the total amount of the alcohol component, the carboxylic acid component, and the recycled PET), and It is preferably 1.5 parts by mass or less, more preferably 1.0 parts by mass or less. Gallic acid etc. are mentioned as an esterification co-catalyst. The amount of the esterification promoter used is preferably 0.001 parts by mass or more, more preferably 0.01 parts by mass or more, and preferably 0.5 parts by mass or less, more preferably 0.1 parts by mass or less, relative to 100 parts by mass of the raw material. is. Polymerization inhibitors include tert-butyl catechol and the like. The amount of the polymerization inhibitor used is preferably 0.001 parts by mass or more, more preferably 0.01 parts by mass or more, and preferably 0.5 parts by mass or less, more preferably 0.1 parts by mass or less, relative to 100 parts by mass of the raw material. be.

In addition, in the present invention, the polyester resin may be a polyester resin that has been modified to such an extent that its properties are not substantially impaired. Modified polyester resins include, for example, grafting or blocking with phenol, urethane, epoxy, etc. by the methods described in JP-A-11-133668, JP-A-10-239903, JP-A-8-20636, etc. Among the modified polyester resins, urethane-modified polyester resins obtained by urethane-extending a polyester resin with a polyisocyanate compound are preferred.

The styrenic resin segment is an addition polymer of raw material monomers containing styrenic compounds.

Examples of the styrene-based compound include styrene derivatives such as α-methylstyrene and vinyltoluene, in addition to styrene, and styrene is preferred.

The content of the styrenic compound is preferably 50% by mass or more, more preferably 60% by mass or more, and still more preferably 70% by mass or more in the raw material monomer of the styrenic resin segment from the viewpoint of storage under high humidity. and is preferably 95% by mass or less, more preferably 93% by mass or less, and still more preferably 90% by mass or less.

In addition, the styrene-based resin may contain a (meth)acrylic acid alkyl ester having an alkyl group having 7 or more carbon atoms as a raw material monomer. Examples of (meth)acrylic acid alkyl esters include 2-ethylhexyl (meth)acrylate, (iso)octyl (meth)acrylate, (iso)decyl (meth)acrylate, and (iso)stearyl (meth)acrylate. mentioned. It is preferable to use one or more of these. In the present specification, "(iso)" means including both cases where this group exists and cases where it does not exist, and when these groups do not exist, normal indicates that Moreover, "(meth)acrylic acid" indicates acrylic acid, methacrylic acid, or both.

The number of carbon atoms in the alkyl group in the (meth)acrylic acid alkyl ester as the raw material monomer for the styrene resin is preferably 7 or more, more preferably 8 or more, from the viewpoint of improving the low-temperature fixability of the toner. is 22 or less, more preferably 20 or less. The number of carbon atoms in the alkyl ester refers to the number of carbon atoms derived from the alcohol component that constitutes the ester.

The content of the (meth)acrylic acid alkyl ester having an alkyl group of 7 or more carbon atoms is preferably 5% by mass or more, more preferably 7% by mass or more, and still more preferably 10% by mass in the raw material monomer of the styrene resin. and preferably 50% by mass or less, more preferably 40% by mass or less, and even more preferably 30% by mass or less.

Raw material monomers for styrene resins include raw material monomers other than styrene compounds and (meth)acrylic acid alkyl esters, such as ethylenically unsaturated monoolefins such as ethylene and propylene; diolefins such as butadiene; Halovinyls; vinyl esters such as vinyl acetate and vinyl propionate; ethylenic monocarboxylic acid esters such as dimethylaminoethyl (meth)acrylate; vinyl ethers such as methyl vinyl ether; vinylidene halides such as vinylidene chloride; N-vinyl compounds such as pyrrolidone may also be included.

The addition polymerization reaction of raw material monomers for the styrene resin segment is carried out in the presence of a polymerization initiator such as dibutyl peroxide or dicumyl peroxide, a polymerization inhibitor, a cross-linking agent, or the like, in the presence or absence of an organic solvent. However, the temperature conditions are preferably 110°C or higher, more preferably 140°C or higher, and preferably 200°C or lower, more preferably 170°C or lower.

When using an organic solvent for the addition polymerization reaction, xylene, toluene, methyl ethyl ketone, acetone, etc. can be used. The amount of the organic solvent used is preferably 10 parts by mass or more and 50 parts by mass or less with respect to 100 parts by mass of the raw material monomer for the styrene-based resin segment.

Both reactive monomers have, in the molecule, at least one functional group selected from the group consisting of a hydroxyl group, a carboxyl group, an epoxy group, a primary amino group and a secondary amino group, preferably a hydroxyl group and/or a carboxyl group. A compound having a group, more preferably a carboxy group, and an ethylenically unsaturated bond is preferred, and at least one selected from the group consisting of acrylic acid, methacrylic acid, fumaric acid, maleic acid and maleic anhydride is more preferred, At least one selected from the group consisting of acrylic acid, methacrylic acid and fumaric acid is more preferable from the viewpoint of reactivity in polycondensation reaction and addition polymerization reaction. However, when used together with a polymerization inhibitor, polyvalent carboxylic acid compounds having an ethylenically unsaturated bond such as fumaric acid function as raw material monomers for polyester resins. In this case, fumaric acid or the like is not a bireactive monomer but a starting monomer for the polyester resin.

The amount of the bi-reactive monomer used is preferably 1 mol or more per 100 mol in total of the alcohol component of the polyester resin, from the viewpoint of enhancing the dispersibility of the styrene resin and the polyester resin and improving the durability of the toner. , more preferably 2 mol or more, and from the viewpoint of low-temperature fixability, it is preferably 30 mol or less, more preferably 20 mol or less. Here, the alcohol component also includes ethylene glycol units contained in recycled PET.
In addition, the amount of the bi-reactive monomer used is preferable from the viewpoint of enhancing the dispersibility of the styrene resin and the polyester resin and improving the durability of the toner with respect to a total of 100 parts by mass of the raw material monomers of the styrene resin. is 1 part by mass or more, more preferably 2 parts by mass or more, and from the viewpoint of low-temperature fixability, preferably 30 parts by mass or less, more preferably 20 parts by mass or less, even more preferably 15 parts by mass or less, and even more preferably is 10 parts by mass or less. Here, the polymerization initiator is included in the sum of the raw material monomers for the styrene resin.

In addition to the polyester resin segment and the styrenic resin segment, from the viewpoint of durability, the composite resin further contains a structural unit derived from the hydrocarbon wax W having at least one of a hydroxyl group and a carboxyl group (a structural unit derived from the hydrocarbon wax W structural unit).

The hydrocarbon wax W has one or both of a hydroxyl group and a carboxy group, and preferably has a hydroxyl group and a carboxy group from the viewpoint of improving durability.

The hydrocarbon wax W is obtained, for example, by modifying an unmodified hydrocarbon wax by a known method. Raw materials for the hydrocarbon wax W include, for example, paraffin wax, Fischer-Tropsch wax, microcrystalline wax, polyethylene wax, polypropylene wax, etc. Among these, paraffin wax and Fischer-Tropsch wax are preferred.

Commercial products of hydrocarbon waxes having a hydroxyl group include "Uniline 700", "Uniline 425", and "Uniline 550" (manufactured by Baker Petrolite).

Examples of commercially available hydrocarbon waxes having a carboxyl group include maleic anhydride-modified ethylene-propylene copolymer "Hi-Wax 1105A" (manufactured by Mitsui Chemicals, Inc.).

Commercially available hydrocarbon waxes having a hydroxyl group and a carboxyl group include "Paracol 6420", "Paracol 6470" and "Paracol 6490" (manufactured by Nippon Seiro Co., Ltd.).

The melting point of the hydrocarbon wax is preferably 50°C or higher, more preferably 60°C or higher, and even more preferably 65°C or higher from the viewpoint of durability, and preferably 100°C or lower from the viewpoint of low-temperature fixability. It is more preferably 90°C or lower, and still more preferably 85°C or lower.

From the viewpoint of durability, the acid value of the hydrocarbon wax (W) is preferably 1 mgKOH/g or more, more preferably 5 mgKOH/g or more, still more preferably 10 mgKOH/g or more, and preferably 30 mgKOH/g or less. , more preferably 25 mgKOH/g or less, still more preferably 20 mgKOH/g or less.

From the viewpoint of durability, the hydroxyl value of the hydrocarbon wax W is preferably 35 mgKOH/g or more, more preferably 50 mgKOH/g or more, still more preferably 70 mgKOH/g or more, and preferably 180 mgKOH/g or less. It is preferably 150 mgKOH/g or less, more preferably 120 mgKOH/g or less.

From the viewpoint of durability, the number average molecular weight of the hydrocarbon wax W is preferably 500 or more, more preferably 600 or more, still more preferably 700 or more, and preferably 2000 or less, more preferably 1700 or less, still more preferably. is less than or equal to 1500.

The content of the structural unit derived from the hydrocarbon wax W is preferably 1 part by mass or more, more preferably 3 parts by mass or more, with respect to 100 parts by mass as the total amount of the polyester resin segment and the styrenic resin segment, and It is preferably 10 parts by mass or less, more preferably 8 parts by mass or less.

The composite resin can be produced, for example, by a method including a step (A) of polycondensation reaction using raw material monomers for the polyester resin segment and a step (B) of addition polymerization reaction using raw material monomers for the styrenic resin segment.
Step (B) may be performed after step (A), step (A) may be performed after step (B), or step (A) and step (B) may be performed simultaneously. In addition, step (A) and step (B) are preferably carried out in the same container.

Further, instead of the step (A) of conducting a polycondensation reaction, a prepolymerized polycondensation resin may be used. When the step (A) and the step (B) are carried out in parallel, the mixture containing the raw material monomers for the styrene resin segment may be added dropwise to the mixture containing the raw material monomers for the polyester resin segment to react. can also

When a hydrocarbon wax is used, it is preferable to carry out the polycondensation reaction of the raw material monomers of the polyester resin segment in the presence of the hydrocarbon wax. Also, the bi-reactive monomer is preferably used together with the raw material monomer for the styrenic resin segment.

The mass ratio of the polyester resin segment to the styrene resin segment (polyester resin segment/styrene resin segment) in the composite resin is preferably 50/50 or more, more preferably 55/45 or more, and still more preferably 55/45 or more, from the viewpoint of durability. 58/42 or more, and preferably 95/5 or less, more preferably 90/10 or less, even more preferably 80/20 or less, even more preferably 75/25 or less, and even more preferably 68/32 or less. In the above calculation, the mass of the polyester resin segment is the mass obtained by subtracting the amount of reaction water dehydrated by the polycondensation reaction from the mass of the raw material monomer of the polyester resin segment used, and the amount of both reactive monomers. is included in the raw material monomer amount of the polyester resin segment. Further, the amount of the styrene resin segment is the total amount of the raw material monomer of the styrene resin segment and the polymerization initiator.

In the present invention, the composite resin may be amorphous or crystalline, but an amorphous composite resin is preferred from the viewpoint of durability.
The crystallinity of the resin is represented by the ratio of the softening point to the maximum endothermic peak temperature measured by a differential scanning calorimeter, that is, the crystallinity index defined by the value of [softening point/maximum endothermic peak temperature]. The crystalline resin is a resin having a crystallinity index of 0.6 or more, preferably 0.7 or more, more preferably 0.9 or more, and 1.4 or less, preferably 1.2 or less, more preferably 1.1 or less.
On the other hand, the amorphous resin is a resin having a crystallinity index of greater than 1.4, preferably greater than 1.5, and more preferably greater than 1.6, or less than 0.6 when no endothermic peak is observed. , preferably 0.5 or less.
The crystallinity of the resin can be adjusted by the type and ratio of raw material monomers, production conditions (eg, reaction temperature, reaction time, cooling rate), and the like. The maximum endothermic peak temperature refers to the temperature of the peak with the maximum peak area among the observed endothermic peaks. In a crystalline resin, the maximum endothermic peak temperature is defined as the melting point.

The softening point of the composite resin is preferably 90°C or higher, more preferably 100°C or higher, from the viewpoint of durability, and preferably 160°C or lower, more preferably 150°C or lower, from the viewpoint of low-temperature fixability. More preferably, it is 140°C or less.

The glass transition temperature of the composite resin is preferably 40°C or higher, more preferably 45°C or higher, and even more preferably 50°C or higher from the viewpoint of durability, and preferably 80°C or lower from the viewpoint of low-temperature fixability. , more preferably 70°C or less.

The acid value of the composite resin is preferably 2 mgKOH/g or more, more preferably 5 mgKOH/g or more, still more preferably 7.5 mgKOH/g or more, still more preferably 10 mgKOH/g or more, from the viewpoint of low-temperature fixability, and From the viewpoint of hygroscopicity, it is preferably 40 mgKOH/g or less, more preferably 30 mgKOH/g or less.

The number average molecular weight of the composite resin is preferably 1,000 or more, more preferably 1,500 or more, and still more preferably 2,000 or more from the viewpoint of durability, and preferably 5,000 or less, more preferably 5,000 or less, from the viewpoint of low-temperature fixability. It is 4,500 or less, more preferably 4,000 or less.

The weight-average molecular weight of the composite resin is preferably 10,000 or more, more preferably 30,000 or more, and still more preferably 50,000 or more from the viewpoint of durability, and preferably 1,000,000 or less, more preferably 1,000,000 or less, from the viewpoint of low-temperature fixability. 500,000 or less, more preferably 300,000 or less.

From the viewpoint of low-temperature fixability, the core preferably further contains a crystalline polyester resin.

As the crystalline polyester resin, for example, a polycondensate of an alcohol component containing an aliphatic diol and a carboxylic acid component containing an aliphatic dicarboxylic acid compound is preferable.

Aliphatic diols include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol , 1,8-octanediol, neopentyl glycol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, and the like. , may be used in combination of two or more. Among these, 1,10-decanediol is preferred.

From the viewpoint of low-temperature fixability, the aliphatic diol is preferably an α,ω-aliphatic diol having a hydroxyl group at the end of the carbon chain, more preferably an α,ω-straight-chain alkanediol. .

The number of carbon atoms in the aliphatic diol is preferably 6 or more from the viewpoint of dispersibility of the colorant, and preferably 14 or less, more preferably 12 or less from the viewpoint of storage stability.

The content of the aliphatic diol in the alcohol component is preferably 70 mol% or more, more preferably 80 mol% or more, still more preferably 90 mol% or more, still more preferably 95 mol% or more.

Other alcohol components include aromatic diols such as alkylene oxide adducts of bisphenol A, trihydric or higher alcohols such as sorbitol, pentaerythritol, glycerin and trimethylolpropane.

Aliphatic dicarboxylic acid compounds include succinic acid (4 carbons), fumaric acid (4 carbons), adipic acid (6 carbons), suberic acid (8 carbons), azelaic acid (8 carbons), : 9), sebacic acid (carbon number: 10), dodecanedioic acid (carbon number: 12), tetradecanedioic acid (carbon number: 14), succinic acid having an alkyl group or alkenyl group in the side chain, these acids Examples thereof include anhydrides and alkyl esters of these acids having 1 to 3 carbon atoms.

The number of carbon atoms in the aliphatic dicarboxylic acid compound is preferably 4 or more from the viewpoint of low temperature fixability, and preferably 14 or less, more preferably 12 or less from the viewpoint of storage stability.

The content of the aliphatic dicarboxylic acid compound in the carboxylic acid component is preferably 70 mol% or more, more preferably 80 mol% or more, still more preferably 90 mol% or more, still more preferably 95 mol% or more.

Other carboxylic acid components include aromatic dicarboxylic acid-based compounds, aliphatic dicarboxylic acid-based compounds, and trivalent or higher carboxylic acid-based compounds.

The equivalent ratio of the carboxy group of the carboxylic acid component to the hydroxyl group of the alcohol component (COOH group/OH group) is preferably 0.8 or more, more preferably 0.9 or more, from the viewpoint of storage stability, and from the viewpoint of low temperature fixability. Therefore, it is preferably 1.2 or less, more preferably 1.1 or less.

The conditions for the polycondensation reaction between the alcohol component and the carboxylic acid component are the same as those for the amorphous polyester resin, except that the preferred reaction temperature is 120° C. or higher and 230° C. or lower.

The softening point of the crystalline polyester resin is preferably 60°C or higher, more preferably 70°C or higher, from the viewpoint of durability, and preferably 110°C or lower, more preferably 100°C or lower, from the viewpoint of low-temperature fixability. is.

The melting point of the crystalline polyester resin is preferably 50°C or higher, more preferably 60°C or higher, from the viewpoint of durability, and preferably 110°C or lower, more preferably 100°C or lower, from the viewpoint of low-temperature fixability. is.

The acid value of the crystalline polyester resin is preferably 3 mgKOH/g or more, more preferably 5 mgKOH/g or more, from the viewpoint of durability, and preferably 35 mgKOH/g or less, more preferably 35 mgKOH/g or less, from the viewpoint of low-temperature fixability. is less than 30mgKOH/g.

The mass ratio of the composite resin to the crystalline polyester resin (composite resin/crystalline polyester resin) is preferably 55/45 or more, more preferably 60/40 or more, and preferably 90/10 or less, more preferably is 85/15 or less, more preferably 80/20 or less.

The total content of the composite resin and the crystalline polyester resin is preferably 60% by mass or more, more preferably 80% by mass or more, still more preferably 90% by mass or more, in the resin constituting the core (core resin). It is preferably 95% by mass or more, more preferably 98% by mass or more, and still more preferably 100% by mass. Other resins include, for example, styrene-propylene copolymer, styrene-butadiene copolymer, styrene-vinyl chloride copolymer, styrene-vinyl acetate copolymer, styrene-maleic acid copolymer, styrene-acrylic acid. Styrene-based resins, epoxy-based resins, rosin-modified maleic acid resins, polyethylene-based resins, which are homopolymers or copolymers containing styrene or styrene substituents such as ester copolymers and styrene-methacrylate copolymers, One or more selected from resins such as polypropylene-based resins, polyurethane-based resins, silicone-based resins, phenol-based resins, and aliphatic or alicyclic hydrocarbon resins can be used.

The proportion of the core resin in the core is preferably 60% by mass or more, more preferably 70% by mass or more, still more preferably 75% by mass or more, and preferably 95% by mass or less, more preferably 93% by mass. It is below.

The shell contains a polyester resin containing polyester resin segments Ps. In the present invention, the polyester resin includes a composite resin in which a polyester resin segment Ps and a styrene resin segment are combined, but a polyester resin (which is the polyester resin segment Ps itself and is also referred to as a polyester resin Ps) is preferable.

The polyester resin segment Ps is a polycondensate of an alcohol component and a carboxylic acid component or a polycondensate of an alcohol component, a carboxylic acid component, and regenerated polyethylene terephthalate.

Examples of alcohol components include alkylene oxide adducts of aromatic diols, linear or branched aliphatic diols, alicyclic diols, and polyhydric alcohols having a valence of 3 or more, as in the polyester resin segment Pc of the core resin. Among these, the alkylene oxide adduct of bisphenol A represented by formula (I) is preferred, and the ethylene oxide adduct of bisphenol A is more preferred.

Raw materials other than the alcohol component (carboxylic acid component and recycled PET) and physical properties are the same as those of the polyester resin segment Pc of the core resin.

The content of the polyester resin segment Ps in the resin constituting the shell (shell resin) is preferably 60% by mass or more, more preferably 80% by mass or more, still more preferably 90% by mass or more, and still more preferably 95% by mass. Above, more preferably 98% by mass or more, more preferably 100% by mass.

In the present invention, at least one of the polyester resin segment Pc and the polyester resin segment Ps is a polycondensate of an alcohol component, a carboxylic acid component, and recycled polyethylene terephthalate, and the polyester resin segment Pc is an alcohol component, a carboxylic acid component, and a recycled polycondensate. It is a polycondensate with polyethylene terephthalate, and the polyester resin segment Ps is preferably a polycondensate of an alcohol component and a carboxylic acid component. Moreover, from the viewpoint of transfer efficiency, the polyester resin segment Ps is preferably a polycondensate of an alcohol component, a carboxylic acid component, and regenerated polyethylene terephthalate.

In the toner of the present invention, the core and/or shell, preferably the core, contains a coloring agent, a release agent, a charge control agent, a magnetic powder, a fluidity improver, a conductivity control agent, a reinforcing filler such as a fibrous substance, Additives such as antioxidants and cleaning improvers may be contained.

As the coloring agent, dyes, pigments, magnetic substances, etc., which are used as coloring agents for toners, can be used. For example, Carbon Black, Phthalocyanine Blue, Permanent Brown FG, Brilliant First Scarlet, Pigment Red 122, Pigment Green B, Rhodamine-B Base, Solvent Red 49, Solvent Red 146, Solvent Blue 35, Quinacridone, Carmine 6B, Isoindoline, Disazo Yellow. etc. In the present invention, the toner may be either black toner or color toner.

The content of the colorant in the toner is preferably 1% by mass or more, more preferably 2% by mass or more, and preferably 40% by mass or less, from the viewpoint of improving the image density and low-temperature fixability of the toner. It is more preferably 20% by mass or less, still more preferably 10% by mass or less.

Release agents include hydrocarbon waxes such as polypropylene wax, polyethylene wax, polypropylene polyethylene copolymer wax, microcrystalline wax, paraffin wax, Fischer-Tropsch wax, Sasol wax, and oxides thereof; carnauba wax, montan Waxes and their deacidified waxes, ester waxes such as fatty acid ester waxes; fatty acid amides, fatty acids, higher alcohols, fatty acid metal salts and the like;

The melting point of the releasing agent is preferably 60° C. or higher, more preferably 70° C. or higher, from the viewpoint of toner durability, and preferably 160° C. or lower, more preferably 140° C., from the viewpoint of low-temperature fixability. 120° C. or lower, more preferably 110° C. or lower.

The content of the release agent in the toner is preferably 1% by mass or more, preferably 15% by mass or less, and more preferably 10% by mass, from the viewpoint of low-temperature fixability and offset resistance of the toner. 8% by mass or less, more preferably 8% by mass or less.

The core-shell type electrostatic image developing toner of the present invention comprises:
Step 1: a step of aggregating core resin particles containing a core resin in an aqueous medium to obtain aggregated particles (I);
Step 2: a step of aggregating shell resin particles containing a shell resin on the surface of the aggregated particles (I) obtained in step 1 to obtain aggregated particles (II); It is preferable to produce by a method including a step of fusing the obtained aggregated particles (II) to obtain core-shell particles.

In step 1, the core resin particles are composed of, for example, a resin component containing a core resin, and optionally optional components such as a colorant and a release agent (hereinafter, the resin component and optional components are collectively referred to as "resin component etc.) is dispersed in an aqueous medium to obtain an aqueous dispersion.

The aqueous medium preferably contains water as a main component, and from the viewpoint of improving the dispersion stability of the aqueous dispersion and from the viewpoint of environmental friendliness, the water content in the aqueous medium is preferably 80% by mass or more. , more preferably 90% by mass or more, still more preferably 95% by mass or more, still more preferably 98% by mass or more, and still more preferably 100% by mass. As water, deionized water or distilled water is preferred.

Components other than water that the aqueous medium may contain include alkyl alcohols with 1 to 5 carbon atoms; dialkyl ketones with 3 to 5 carbon atoms, such as acetone and methyl ethyl ketone; and organic solvents that dissolve in water, such as cyclic ethers such as tetrahydrofuran. is used. Among these, alkyl alcohols having 1 to 5 carbon atoms that do not dissolve the polyester resin are preferable, and methanol, ethanol, isopropanol, or butanol is more preferable, from the viewpoint of preventing contamination of the toner with the organic solvent.

Methods for obtaining an aqueous dispersion of the resin particles for the core include a method in which the resin component or the like is added to an aqueous medium and subjected to dispersion treatment using a dispersing machine or the like; and phase inversion emulsification (phase inversion emulsification). Among these, the method using phase inversion emulsification is preferable from the viewpoint of improving the low-temperature fixability and durability of the toner.

As the phase inversion emulsification method, a resin component or the like is dissolved in an organic solvent to obtain an organic solvent solution of the resin component or the like, and an aqueous medium is added to the obtained solution to perform phase inversion emulsification (A), or A method (B) of phase inversion emulsification by adding an aqueous medium to a resin mixture obtained by melting and mixing the components is exemplified. Method (A) is preferred from the viewpoint of obtaining a homogeneous aqueous dispersion of core resin particles.

As the organic solvent used in the phase inversion emulsification method, the solubility parameter (SP value: POLYMER HANDBOOK THIRD EDITION 1989 by John Wiley & Sons, Inc) is preferably 15.0 MPa ^1/2 or more, more preferably 16.0 MPa ^{1/ 2} or more, more preferably 17.0 MPa ^1/2 or more, and preferably 26.0 MPa ^1/2 or less, more preferably 24.0 MPa ^1/2 or less, still more preferably 22.0 MPa ^1/2 or less organic solvent preferable.

Organic solvents include alcoholic solvents such as ethanol (26.0), isopropanol (23.5), and isobutanol (21.5); Ketone solvents; ether solvents such as dibutyl ether (16.5), tetrahydrofuran (18.6) and dioxane (20.5); and acetate solvents such as ethyl acetate (18.6) and isopropyl acetate (17.4). The numerical value in parentheses after each solvent is its SP value (unit: MPa ^1/2 ). Among these, from the viewpoint of easy removal from the mixed solution after addition of the aqueous medium, one or more selected from ketone-based solvents and acetic acid ester-based solvents are preferable, and more preferably selected from methyl ethyl ketone, ethyl acetate and isopropyl acetate. more preferably methyl ethyl ketone.

In the phase inversion emulsification method, it is preferable to treat the resin with a neutralizing agent.

A basic substance etc. are mentioned as a neutralizing agent. Basic substances include alkali metal hydroxides such as lithium hydroxide, sodium hydroxide and potassium hydroxide; nitrogen-containing basic substances such as ammonia, trimethylamine, ethylamine, diethylamine, triethylamine, diethanolamine, triethanolamine and tributylamine Among them, from the viewpoint of improving the dispersion stability and cohesiveness of the core resin particles, preferably at least one selected from ammonia and alkali metal hydroxides, more preferably ammonia and At least one selected from sodium hydroxide, more preferably sodium hydroxide.

The use equivalent (mol%) of the neutralizing agent to the acid groups of the resin is preferably 10 mol% or more, more preferably 30 mol% or more, and preferably 150 mol% or less, more preferably 120 mol%. 100 mol % or less, more preferably 100 mol % or less.
The equivalent amount (mol%) of the neutralizing agent to be used can be determined by the following formula.
Equivalent amount of neutralizing agent used (mol%) = [{adding mass of neutralizing agent (g)/equivalent amount of neutralizing agent}/[{acid value of resin (mgKOH/g) x mass of resin (g)}/ (56 x 1000)]] x 100

The temperature at which the aqueous medium is added is preferably 20°C or higher, more preferably 40°C or higher, still more preferably 50°C or higher, from the viewpoint of improving the dispersion stability of the core resin particles. It is 90°C or lower, more preferably 80°C or lower, and still more preferably 70°C or lower.

From the viewpoint of obtaining small-diameter core resin particles, the addition rate of the aqueous medium is preferably 0.1 part by mass with respect to 100 parts by mass of the core resin constituting the core resin particles until the phase inversion is completed. / min or more, more preferably 0.5 mass parts / min or more, still more preferably 3 mass parts / min or more, and preferably 50 mass parts / min or less, more preferably 30 mass parts / min or less, still more preferably It is 20 parts by mass/minute or less, more preferably 10 parts by mass/minute or less. There is no limit to the rate of addition of the aqueous medium after phase inversion.

After phase inversion emulsification, the organic solvent may be removed from the resulting dispersion, if desired. As a method for removing the organic solvent, distillation is preferred because it dissolves in water. The residual amount of the organic solvent in the aqueous dispersion is preferably 1% by mass or less, more preferably 0.5% by mass or less, and still more preferably substantially 0% by mass.

The content of the core resin in the total resin components contained in the core resin particles is preferably 80% by mass or more, more preferably 90% by mass or more, still more preferably 95% by mass or more, and still more preferably 100% by mass. be.

From the viewpoint of improving the productivity of the toner and improving the dispersion stability of the aqueous dispersion of the core resin particles, the solid content concentration of the aqueous dispersion of the core resin particles is preferably 5 mass % or more. It is preferably 10% by mass or more, more preferably 15% by mass or more, and is preferably 50% by mass or less, more preferably 40% by mass or less, further preferably 30% by mass or less, further preferably 25% by mass or less. be. The solid content is the total amount of non-volatile components such as resins, colorants and surfactants.

The content of the core resin in the solid content of the aqueous dispersion of core resin particles is preferably 80% by mass or more, more preferably 85% by mass or more, and still more preferably 90% by mass or more. % by mass or less, preferably 98% by mass or less.

The volume median particle size ( _D50 ) of the core resin particles in the aqueous dispersion is preferably 0.05 μm or more, more preferably 0.10 μm or more, still more preferably 0.12 μm or more, and preferably 0.80 μm or less. , more preferably 0.40 μm or less, still more preferably 0.30 μm or less.
In addition, the CV value of the core resin particles is preferably 5% or more, more preferably 15% or more, and still more preferably 20% or more, from the viewpoint of improving the productivity of the aqueous dispersion of the core resin particles. From the viewpoint of obtaining a toner capable of obtaining high-quality images, the content is preferably 50% or less, more preferably 40% or less, and even more preferably 35% or less.
In addition, in the present invention, the CV value is calculated according to the following formula.
CV value (%) = (standard deviation of particle size distribution / volume average particle size) x 100

Optional components such as a colorant and a releasing agent can be dispersed in an aqueous medium even if they are mixed with the core resin when preparing the aqueous dispersion of the core resin particles as described above. Aggregated particles (I) may be obtained by separately preparing a liquid and mixing it with an aqueous dispersion of core resin particles.

For example, an aqueous dispersion of a release agent (release agent dispersion) is obtained by dispersing release agent particles in a release agent and an aqueous medium at a temperature equal to or higher than the melting point of the release agent using a disperser. is preferably obtained by

The dispersion of the release agent particles in the aqueous medium is preferably carried out in the presence of a surfactant from the viewpoint of improving the dispersion stability of the release agent particles and obtaining uniform aggregated particles.

Examples of surfactants include anionic surfactants such as sodium dodecylbenzenesulfonate, sodium dodecylsulfate, sodium lauryl ether sulfate and dipotassium alkenylsuccinate; cationic surfactants; nonionic surfactants and the like.

The content of the surfactant in the release agent dispersion is determined from the viewpoint of improving the dispersion stability of the release agent particles and from the viewpoint of improving the cohesiveness of the release agent particles during toner production and preventing release. , preferably 0.1% by mass or more, more preferably 0.3% by mass or more, still more preferably 0.5% by mass or more, and preferably 5.0% by mass or less, more preferably 3.0% by mass or less.

Dispersers used include homogenizers, ultrasonic dispersers, high-pressure dispersers, and the like.

Moreover, before using the dispersing machine, it is preferable to pre-disperse the optional components, the surfactant and the aqueous medium in advance with a mixer such as a homomixer or a ball mill.
The aqueous medium used for the optional component is the same as the aqueous medium used for obtaining the aqueous dispersion of the core resin particles.

The solid content concentration of the release agent dispersion is preferably 5% by mass or more, more preferably 10% by mass or more, from the viewpoint of improving the productivity of the toner and the viewpoint of improving the dispersion stability of the release agent particles. It is more preferably 15% by mass or more, and preferably 50% by mass or less, more preferably 30% by mass or less, and even more preferably 25% by mass or less.

The volume median particle diameter (D ₅₀ ) of the release agent particles is preferably 0.10 μm or more, more preferably 0.20 μm or more, still more preferably 0.30 μm or more, from the viewpoint of obtaining uniform aggregated particles. is 1.0 μm or less, more preferably 0.80 μm or less, still more preferably 0.60 μm or less.

An aqueous dispersion of a colorant (colorant dispersion) is also preferably obtained by dispersing colorant particles using a disperser, preferably in the presence of a surfactant, similarly to the release agent dispersion. .

Examples of surfactants used for preparing the colorant dispersion include nonionic surfactants, anionic surfactants, cationic surfactants, and the like. From the viewpoint of improving the cohesiveness of the colorant particles and the resin particles for the core and the resin particles for the shell, an anionic surfactant is preferred. Specific examples include sodium dodecylbenzenesulfonate, sodium dodecylsulfate, sodium lauryl ether sulfate, dipotassium alkenylsuccinate and the like, preferably sodium dodecylbenzenesulfonate.

The content of the surfactant in the colorant dispersion is preferably from the viewpoint of improving the dispersion stability of the colorant particles and from the viewpoint of improving the cohesiveness of the colorant particles during toner production and preventing the separation. It is 0.1% by mass or more, more preferably 0.5% by mass or more, still more preferably 1.0% by mass or more, and preferably 5.0% by mass or less, more preferably 4.5% by mass or less.

The solid content concentration of the colorant dispersion is preferably 5% by mass or more, more preferably 10% by mass, from the viewpoint of improving the productivity of the toner and improving the dispersion stability of the aqueous dispersion of the colorant particles. Above, more preferably 15% by mass or more, preferably 50% by mass or less, more preferably 40% by mass or less, and even more preferably 30% by mass or less.

The volume-median particle size (D ₅₀ ) of the colorant particles is preferably 0.05 μm or more, more preferably 0.08 μm or more, still more preferably 0.10 μm or more, from the viewpoint of obtaining a toner capable of obtaining high-quality images, And it is preferably 0.50 μm or less, more preferably 0.30 μm or less, and still more preferably 0.15 μm or less.

When obtaining a dispersion of aggregated particles (I) in step 1, it is preferable to add an aggregating agent from the viewpoint of efficient aggregation.
The aggregating agent is preferably an electrolyte, more preferably a salt, from the viewpoint of obtaining a toner having a desired particle size while preventing excessive aggregation. Examples of the flocculant include organic flocculants such as quaternary salt cationic surfactants and polyethyleneimine; inorganic flocculants such as inorganic metal salts, inorganic ammonium salts, and divalent or higher metal complexes; Among these, from the viewpoint of improving cohesiveness and obtaining uniform aggregated particles, inorganic flocculants are preferred, inorganic metal salts or inorganic ammonium salts are more preferred, and inorganic ammonium salts are even more preferred.

The valence of the cation of the inorganic flocculant is preferably pentavalent or less, more preferably divalent or less, still more preferably monovalent, from the viewpoint of obtaining a toner having a desired particle size while preventing excessive aggregation.
The monovalent cation of the inorganic flocculant includes sodium ion, potassium ion, ammonium ion and the like, among which ammonium ion is preferred.

Examples of inorganic metal salts include metal salts such as sodium sulfate, sodium nitrate, sodium chloride, calcium chloride and calcium nitrate, and inorganic metal salt polymers such as polyaluminum chloride and polyaluminum hydroxide.
Examples of inorganic ammonium salts include ammonium sulfate, ammonium chloride, and ammonium nitrate.

Ammonium sulfate is preferred as the flocculant.

The amount of the flocculant used is preferably 5 parts by mass or more, more preferably 10 parts by mass or more, still more preferably 20 parts by mass, with respect to 100 parts by mass of the core resin, from the viewpoint of controlling aggregation to obtain a desired particle size. It is not less than 10 parts by mass, and preferably 50 parts by mass or less, more preferably 45 parts by mass or less.

The flocculant is preferably added dropwise to the mixed dispersion. The flocculant may be added all at once, intermittently or continuously. Sufficient stirring is preferably performed during and after the addition.

The flocculant is preferably added dropwise as an aqueous solution from the viewpoint of controlling flocculation to obtain agglomerated particles with a desired particle size, and the concentration of the flocculant aqueous solution is preferably 2% by mass or more, more preferably 4% by mass. It is the above and is preferably 40% by mass or less, more preferably 30% by mass or less, still more preferably 20% by mass or less, and even more preferably 10% by mass or less.

From the viewpoint of controlling aggregation to obtain aggregated particles having a desired particle size and particle size distribution, it is preferable to adjust the pH of the aqueous solution of the aggregating agent to 7.0 or more and 9.0 or less.

The dropping time of the aggregating agent is preferably 1 minute or longer, more preferably 3 minutes or longer, from the viewpoint of controlling aggregation to obtain aggregated particles having a desired particle size, and from the viewpoint of improving toner productivity. , preferably 120 minutes or less, more preferably 60 minutes or less, still more preferably 40 minutes or less.

The aggregation temperature of the resin particles for the core when the aggregating agent is added in step 1 is preferably 0° C. or higher, more preferably 10° C. or higher, from the viewpoint of controlling aggregation to obtain aggregated particles (I) having a desired particle size. , more preferably 15°C or higher, and preferably 40°C or lower, more preferably 30°C or lower.

Furthermore, from the viewpoint of promoting aggregation and obtaining aggregated particles having a desired particle size and particle size distribution, it is preferable to raise the temperature of the dispersion after adding the aggregating agent. The holding temperature is preferably 45° C. or higher, more preferably 50° C. or higher, and preferably 80° C. or lower, more preferably 70° C. or lower, and still more preferably 65° C. or lower.

The volume-median particle diameter (D ₅₀ ) of the aggregated particles (I) obtained is preferably 2 μm or more, more preferably 3 μm or more, still more preferably 4 μm or more, and preferably 10 μm or less, more preferably 8 μm or less. , more preferably 7 μm or less.

Next, in step 2, shell resin particles containing a shell resin are aggregated on the surface of aggregated particles (I) obtained in step 1 to obtain aggregated particles (II).

In step 2, an aqueous dispersion of shell resin particles containing a shell resin is added to the aggregated particles (I) obtained in step 1 to aggregate the shell resin particles on the surfaces of the aggregated particles (I). , to obtain agglomerated particles (II).

The shell resin particles are produced by dispersing a resin component containing the shell resin in an aqueous medium to obtain an aqueous dispersion of the shell resin particles. The resin particles for shells may be obtained as an aqueous dispersion of resin particles for shells by dispersing a resin component containing a resin for shells and, if necessary, the above optional components in an aqueous medium.
The method for obtaining the aqueous dispersion is the same as in the case of the core resin particles.

From the viewpoint of improving the dispersion stability of the shell resin particles, it is preferable to add a neutralizing agent to the solution. Preferred aspects of the neutralizing agent are the same as in the production of the core resin particles.
The use equivalent (mol%) of the neutralizing agent to the acid groups of the resin is preferably 10 mol% or more, more preferably 30 mol% or more, and preferably 150 mol% or less, more preferably 120 mol%. 100 mol % or less, more preferably 100 mol % or less.

The preferred range of the temperature and rate of addition of the aqueous medium, and the solid content concentration of the resulting aqueous dispersion of the resin particles for shell are the same as the preferred ranges exemplified above for the resin particles for core.

The content of the shell resin in the solid content of the aqueous dispersion of the shell resin particles is preferably 80% by mass or more, more preferably 85% by mass or more, and still more preferably 90% by mass or more. % by mass or less, preferably 98% by mass or less.

The volume-median particle size (D ₅₀ ) of the shell resin particles in the aqueous dispersion is preferably 0.05 μm or more, more preferably 0.08 μm or more, and still more preferably 0.08 μm or more, from the viewpoint of obtaining a toner capable of obtaining high-quality images. It is 0.10 μm or more, and preferably 0.50 μm or less, more preferably 0.40 μm or less, further preferably 0.30 μm or less.

The CV value of the shell resin particles is preferably 5% or more, more preferably 10% or more, and still more preferably 15% or more, from the viewpoint of improving the productivity of the aqueous dispersion of the shell resin particles. From the viewpoint of obtaining a toner capable of obtaining high-quality images, the content is preferably 50% or less, more preferably 40% or less, and even more preferably 30% or less.

The content of the shell resin in the total resin components contained in the shell resin particles is preferably 80% by mass or more, more preferably 90% by mass or more, and still more preferably 90% by mass or more, from the viewpoint of improving the low-temperature fixability and durability of the toner. is 95% by mass or more, more preferably 100% by mass.

Optional components such as a colorant and a release agent can be dispersed in an aqueous medium even if they are mixed with the shell resin when preparing the aqueous dispersion of the shell resin particles in the same manner as in step 1. Aggregated particles (II) may be obtained by separately preparing a dispersion and mixing it with an aqueous dispersion of the shell resin.

An aqueous medium may be added to dilute the dispersion of aggregated particles (I) before the dispersion of aggregated particles (I) and the aqueous dispersion of resin particles for shell are mixed. Further, when the aqueous dispersion of the shell resin particles is added to the dispersion liquid of the aggregated particles (I), in order to efficiently adhere the shell resin particles to the aggregated particles (I), the steps described in step 1 are carried out. A flocculating agent may also be used.

The temperature at which the aqueous dispersion of the shell resin particles is added is preferably 40° C. or higher, more preferably 45° C. or higher, and still more preferably 47° C. or higher, from the viewpoint of improving the low-temperature fixability and durability of the toner. , and preferably 80° C. or lower, more preferably 70° C. or lower, and even more preferably 65° C. or lower.

The aqueous dispersion of resin particles for shells may be added continuously over a certain period of time, may be added at once, or may be added dividedly into multiple times. It is preferable to add it continuously or divide it into multiple additions. By adding in this manner, the shell resin particles are more likely to selectively adhere to the surface of the aggregated particles (I). Above all, from the viewpoint of promoting selective adhesion and improving productivity of the toner, it is preferable to add continuously over a certain period of time.

In the case of continuously adding the aqueous dispersion of the resin particles for the shell, the addition rate is set to 100 parts by mass of the aggregated particles (I) from the viewpoint of obtaining uniform aggregated particles (II) and from the viewpoint of improving toner productivity. is preferably 0.03 parts/minute or more, more preferably 0.1 parts/minute or more, still more preferably 0.3 parts/minute or more, and preferably 2.0 parts by weight or more. The speed is 1.0 parts/minute or less, more preferably 1.5 parts/minute or less, more preferably 1.0 parts/minute or less.

In step 2, the aggregation may be stopped when the aggregated particles have grown to a suitable particle size for the toner.
Methods for stopping aggregation include a method of cooling the dispersion, a method of adding an aggregation inhibitor, and a method of diluting the dispersion. From the viewpoint of reliably preventing unnecessary aggregation, a method of stopping aggregation by adding an aggregation terminator is preferred.

As the aggregation terminator, a surfactant is preferred, and an anionic surfactant is more preferred. Examples of anionic surfactants include alkylbenzene sulfonates, alkyl sulfates, alkyl ether sulfates, polyoxyalkylene alkyl ether sulfates, etc., preferably polyoxyalkylene alkyl ether sulfates, more preferably polyoxyethylene. Lauryl ether sulfate, more preferably sodium polyoxyethylene lauryl ether sulfate. An aggregation terminator can be used individually by 1 type or in combination of 2 or more types.

From the viewpoint of reliably preventing unnecessary aggregation, the addition amount of the aggregation terminator is preferably 0.1 part by mass or more, more preferably 1 part by mass, with respect to 100 parts by mass of the total amount of the core resin particles and the shell resin particles. parts by mass or more, more preferably 2 parts by mass or more, and preferably 15 parts by mass or less, more preferably 10 parts by mass or less, and even more preferably 7 parts by mass or less from the viewpoint of reducing residue in the toner. The aggregation terminator is preferably added in the form of an aqueous solution from the viewpoint of improving toner productivity.

The temperature at which the aggregation terminator is added is preferably the same as the temperature at which the dispersion liquid of the aggregated particles (II) is maintained, preferably 40° C. or higher, more preferably 45° C. or higher, from the viewpoint of improving toner productivity. , more preferably 47°C or higher, and preferably 80°C or lower, more preferably 70°C or lower, and even more preferably 65°C or lower.

In step 2, the volume-median particle size (D ₅₀ ) of the aggregated particles (II) in the resulting dispersion is preferably 2 μm or more, more preferably 3 μm or more, from the viewpoint of improving the low-temperature fixability and durability of the toner. It is more preferably 4 μm or more, and preferably 10 μm or less, more preferably 8 μm or less, and even more preferably 7 μm or less.

Step 3 is a step of fusing the aggregated particles (II) obtained in step 2 to obtain core-shell particles. Particles in the aggregated particles (II), which were mainly physically adhering to each other, are fused together to form core-shell particles (fused particles).

In step 3, from the viewpoint of improving the fusibility of the aggregated particles (II) and improving the low-temperature fixability and durability of the toner, the temperature is higher than the maximum value of the glass transition temperature of the core resin or shell resin. preferably retained.

The holding temperature is preferably 2° C. or higher than the maximum value of the glass transition temperature of the core resin or shell resin, from the viewpoint of improving the fusing properties of the aggregated particles and improving the productivity of the toner. The temperature is more preferably 4°C or higher, more preferably 6°C or higher, and preferably 30°C or lower, more preferably 20°C, higher than the maximum value of the glass transition temperature of the core resin or shell resin. below high temperature.

In this case, the time for holding at a temperature equal to or higher than the maximum value of the glass transition temperature of the core resin or shell resin is preferably 1 minute or more, more preferably 1 minute or more, from the viewpoint of improving the low-temperature fixability and durability of the obtained toner. is 10 minutes or more, more preferably 30 minutes or more, and preferably 240 minutes or less, more preferably 180 minutes or less, and even more preferably 120 minutes or less.

In the core-shell particles, the mass ratio of the shell resin contained in the shell to the core resin contained in the core (shell resin/core resin) is preferably 5/100 or more, more preferably 10/100 or more. , and preferably 60/100 or less, more preferably 50/100 or less, and even more preferably 40/100 or less.

The volume-median particle diameter (D ₅₀ ) of the core-shell particles in the dispersion liquid obtained in step 3 is preferably 2 μm or more, more preferably 3 μm or more, and still more preferably 3 μm or more, from the viewpoint of improving the low-temperature fixability and durability of the toner. is 4 μm or more, and preferably 10 μm or less, more preferably 8 μm or less, and even more preferably 7 μm or less.

The circularity of the core-shell particles in the dispersion obtained in step 3 is preferably 0.955 or more, more preferably 0.960 or more, still more preferably 0.965 or more, from the viewpoint of improving the low-temperature fixability and durability of the toner, and , preferably 0.990 or less, more preferably 0.985 or less, still more preferably 0.980 or less.

The core-shell particles obtained in step 3 are preferably isolated by appropriately performing post-treatment steps.
For example, since the core-shell particles in the dispersion liquid obtained in step 3 are present in the aqueous medium, it is preferable to perform solid-liquid separation first. A suction filtration method or the like is preferably used for the solid-liquid separation.
Washing is preferably performed after solid-liquid separation. At this time, since it is preferable to remove the added surfactant as well, it is preferable to wash with an aqueous medium at a temperature not higher than the cloud point of the surfactant. Washing is preferably performed multiple times.

Drying is then preferably carried out. The temperature during drying is preferably such that the temperature of the core-shell particles themselves is lower than the minimum value of the glass transition temperature of the core resin or shell resin. As a drying method, it is preferable to use a vacuum low-temperature drying method, a vibrating fluidized bed drying method, a spray drying method, a freeze drying method, a flash jet method, or the like. The moisture content after drying is adjusted to preferably 1.5% by mass or less, more preferably 1.0% by mass or less, from the viewpoint of improving the charging characteristics of the toner.

In the toner of the present invention, core-shell particles may be surface-treated with an external additive in order to improve transferability. Examples of external additives include inorganic fine particles such as silica, alumina, titania, zirconia, tin oxide and zinc oxide, and organic fine particles such as melamine resin fine particles and polytetrafluoroethylene resin fine particles. may be

The average particle size of the external additive is preferably 10 nm or more, more preferably 250 nm or less, more preferably 200 nm or less, and still more preferably 90 nm or less, from the viewpoints of toner chargeability, fluidity, and transferability. .

The content of the external additive is preferably 0.05 parts by mass or more, more preferably 0.1 part by mass, with respect to 100 parts by mass of the toner before being treated with the external additive, from the viewpoint of charging property, fluidity, and transferability of the toner. parts or more, more preferably 0.5 parts by mass or more, and preferably 5 parts by mass or less, more preferably 4 parts by mass or less.

The toner of the present invention can be used as a one-component developing toner as it is or as a two-component developing toner mixed with a carrier in an image forming apparatus of a one-component developing system or a two-component developing system.

EXAMPLES The present invention will be specifically described below with reference to Examples, but the present invention is not limited to these Examples. Physical properties of resins and the like can be measured by the following methods.

[Analysis of metal species contained in PET]
Measured under the following conditions using a fluorescent X-ray spectrometer "ZSX100e" (manufactured by Rigaku Corporation).
1) Put about 1.5 g of PET in a sample ring (diameter: 32 mm, length: 5 mm) and press-form with a 10-ton press.
2) Excitation conditions Target: Rh
Tube current: 50mA
Tube voltage: 50mV
Primary filter: OUT
3) Optical system conditions Attenuator: 1/1
Slit: COARSE
Analysis crystal: LiF
Detector: SC
Sample mask diameter: 30mmφ
4) Scanning conditions Spectrum: Cu-Kα
Peak (deg): 45.0
Start (deg): 43
End (deg): 47
Step (deg): 0.02
Scanning speed (deg/min): 30

[IV value of PET]
It can be obtained by dissolving in a mixed solvent of phenol/tetrachloroethane (mass ratio) of 60/40 at a concentration of 4 g/L, measuring with an Ubbelohde viscometer, and calculating according to the following formula.
IV = (-1+√(1+4kη))/(2kC)
[In the formula, k = 0.33, C = 0.004 g/mL, and η = (t1/t0) -1 (t0: the number of seconds in which only the solvent falls, t1: the number of seconds in which the sample solution falls). ]

[Resin softening point]
Using a flow tester "CFT-500D" (manufactured by Shimadzu Corporation), while heating a 1 g sample at a temperature increase rate of 6 ° C / min, a load of 1.96 MPa was applied with a plunger, and the diameter was 1 mm and the length was 1 mm. extruded from the nozzle of Plot the amount of plunger descent of the flow tester against the temperature, and let the softening point be the temperature at which half of the sample flows out.

[Maximum peak temperature of resin absorption]
Using a differential scanning calorimeter "Q-100" (manufactured by TA Instruments Japan Co., Ltd.), weigh 0.01 to 0.02 g of the sample in an aluminum pan and cool it from room temperature (25 ° C) to a cooling rate of 10 ° C. /min to 0°C and hold at 0°C for 1 minute. After that, measure at a heating rate of 10°C/min. Among the observed endothermic peaks, the temperature of the peak having the maximum peak area is defined as the maximum endothermic peak temperature.

[Glass transition temperature of resin]
Using a differential scanning calorimeter "Q-100" (manufactured by TA Instruments Japan), weigh 0.01 to 0.02 g of the sample in an aluminum pan, raise the temperature to 200 ° C, and then decrease the cooling rate from that temperature. Cool to 0°C at 10°C/min. Next, the sample is heated at a heating rate of 10°C/min, and the endothermic peak is measured. The glass transition temperature is defined as the temperature at the intersection of the extended line of the baseline below the maximum endothermic peak temperature and the tangent line showing the maximum slope from the rising portion of the peak to the apex of the peak.

[Acid value of resin]
Measured based on the method of JIS K 0070:1992. However, JIS K 0070 specified mixed solvent of ethanol and ether for the measurement solvent, mixed solvent of acetone and toluene (acetone:toluene = 1:1 (volume ratio)) for amorphous resin, and chloroform for crystalline resin. and dimethylformamide (chloroform:dimethylformamide = 7:3 (volume ratio)).

[Number average molecular weight and weight average molecular weight of resin]
The number average molecular weight and weight average molecular weight are obtained by gel permeation chromatography (GPC) by the following method.
(1) Preparation of sample solution Dissolve the sample in tetrahydrofuran at 40°C so that the concentration becomes 0.5g/100mL. Next, this solution is filtered using a fluororesin filter with 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 measurement Using the following apparatus, tetrahydrofuran is passed as an eluent at a flow rate of 1 mL per minute, and the column is stabilized in a constant temperature bath at 40°C. 100 μL of the sample solution is injected into it and the measurement is performed. The molecular weight of the sample is calculated based on a previously prepared calibration curve. The calibration curve at this time includes several types of monodisperse polystyrene with known molecular weights (manufactured by Tosoh Corporation; ^2.63 × 10 ³ , 2.06 × 10 ⁴ , 1.02 × 10 ⁵ ; , 7.00×10 ³ , 5.04×10 ⁴ ) as standard samples.
Measuring device: CO-8010 (trade name, manufactured by Tosoh Corporation)
Analysis column: GMH _XL + G3000H _XL (both trade names, manufactured by Tosoh Corporation)

[Melting point of wax (release agent)]
Using a differential scanning calorimeter "DSC Q20" (manufactured by TA Instruments Japan Co., Ltd.), weigh 0.01 to 0.02 g of the sample in an aluminum pan and heat it up to 200 ° C at a heating rate of 10 ° C / min. The temperature is raised and then cooled to -10°C at a cooling rate of 5°C/min. Next, the sample is heated up to 180°C at a heating rate of 10°C/min and measured. The maximum endothermic peak temperature observed from the melting endothermic curve thus obtained is taken as the melting point of the release agent.

[Acid value and hydroxyl value of wax]
Measure according to JIS K 0070. However, change the measurement solvent to a mixed solvent of xylene and ethanol (xylene:ethanol = 3:5 (mass ratio)).

[Number average molecular weight (Mn) of wax]
The number average molecular weight (Mn) is determined by the Gel Permeation Chromatography (GPC) method described below.
(1) Dissolve the sample in chloroform at 25°C so that the sample solution has a concentration of 0.5g/100mL, then filter this solution through a fluororesin filter with a pore size of 0.2μm (product name: “DISMIC”, model “ 25JP”, manufactured by ADVANTEC) to remove undissolved components to obtain a sample solution.
(2) Measurement Using the following measurement equipment and analysis column, chloroform as an eluent is flowed at a flow rate of 1 mL/min, the column is stabilized in a constant temperature bath at 40°C, and 100 μL of the sample solution is injected. Molecular weight was determined. The molecular weight (number-average molecular weight Mn) of the sample was obtained from several types of monodisperse polystyrene (product name: “standard polystyrene”; type name (Mw): “A-500 (5.0×10 ² )”, “A1000 (1.01×10 ³ )”, “A2500 (2.63×10 ³ )”, “A-5000 (5.97×10 ³ )”, “F-1 (1.02×10 ⁴ )”, “F-2 (1.81×10 ⁴ )”, “ F-4 (3.97×10 ⁴ )”, “F-10 (9.64×10 ⁴ )”, “F-20 (1.90×10 ⁵ )”, “F-40 (4.27×10 ⁵ )”, “F- 80 (7.06×10 ⁵ )” and “F-128 (1.09×10 ⁶ )”; both are calculated based on a previously prepared calibration curve using Tosoh Corporation) as a standard sample.
・ Measuring device: “HLC-8220GPC” (manufactured by Tosoh Corporation)
・ Analysis column: "GMHXL" and "G3000HXL" (manufactured by Tosoh Corporation)

[Volume Median Particle Diameter (D ₅₀ ) of Colorant Particles and Release Agent Particles]
Measuring device: Laser diffraction particle size measuring machine “LA-920” (manufactured by Horiba, Ltd.)
Measurement conditions: Distilled water is added to the measurement cell, and the volume-median particle size ( _D50 ) is measured at a concentration at which the absorbance is within the appropriate range.

[Solid content concentration of aqueous dispersion]
Using an infrared moisture meter "FD-230" (manufactured by Ketto Kagaku Kenkyusho Co., Ltd.), dry 5 g of the sample under the conditions of drying temperature 150 ° C and measurement mode 96 (monitoring time 2.5 minutes / fluctuation width 0.05%). , to measure the water content (% by mass) of the sample. The solid content is calculated according to the following formula.
Solid content concentration (mass%) = 100 - water content of sample (mass%)

[Circularity of fused particles]
The circularity of the fused particles is measured under the following conditions.
・Measurement device: Flow type particle image analyzer “FPIA-3000” (manufactured by Sysmex Corporation)
- Preparation of dispersion liquid: A dispersion liquid of fusion-bonded particles is diluted with deionized water so that the solid content concentration is 0.001 to 0.05% by mass.
・Measurement mode: HPF measurement mode

[Average particle size of external additive]
The average particle size refers to the number average particle size, and the particle size (average value of major and minor axes) of 500 particles is measured from a scanning electron microscope (SEM) photograph, and the number average value thereof is taken.

[Volume Median Particle Diameter of Core Resin Particles, Shell Resin Particles, Aggregated Particles (I), Aggregated Particles (II), and Toner Particles]
Measuring machine: Coulter Multisizer II (manufactured by Beckman Coulter, Inc.)
Aperture diameter: 50 μm
Analysis software: Coulter Multisizer AccuComp version 1.19 (manufactured by Beckman Coulter, Inc.)
Electrolyte: Isoton II (manufactured by Beckman Coulter, Inc.)
Dispersion liquid: EMULGEN 109P (manufactured by Kao Corporation, polyoxyethylene lauryl ether, HLB (griffin): 13.6) dissolved in an electrolytic solution and adjusted to 5% by mass (core resin particles, shell resin particles, For aggregated particles (I) and aggregated particles (II), the dispersion liquid is used as it is)
Dispersion conditions: Add 10 mg of the measurement sample to 5 mL of the dispersion liquid, disperse for 1 minute with an ultrasonic disperser (machine name: US-1 manufactured by SND Co., Ltd., output: 80 W), and then 25 mL of the electrolytic solution. and dispersed for 1 minute with an ultrasonic disperser to prepare a sample dispersion.
Measurement conditions: Add the sample dispersion to 100 mL of the electrolytic solution so that the particle size of 30,000 particles can be measured in 20 seconds, measure 30,000 particles, and determine the volume from the particle size distribution. Determine the median particle size ( _D50 ).

[CV Values of Core Resin Particles and Shell Resin Particles]
When the volume median particle size is measured, the volume average particle size and the standard deviation of the particle size distribution are obtained, and calculated according to the following formula.
CV value (%) = (standard deviation of particle size distribution/volume average particle size) x 100

Production Example of Alkylene Compound Using propylene tetramer (manufactured by Nippon Oil Co., Ltd., trade name: “Light Tetramer”), fractional distillation was performed under heating conditions of 183 to 208° C. to obtain an alkylene compound (a). The obtained alkylene compound (a) had 40 peaks in gas chromatography mass spectrometry, which will be described later. The distribution of the alkylene compounds was measured according to the analysis by mass spectrometry gas chromatography of alkylene compound A in JP-A-2014-013384, and C ₉ H ₁₈ : 0.5% by mass, C ₁₀ H ₂₀ : 4% by mass, C ₁₁ H ₂₂ : 20% by mass, _C12H24 : 66% _{by mass} , _C13H26 : 9% by mass, _C14H28 : _0.5 % by mass (6 peaks corresponding to alkylene compounds having 9 to 14 carbon atoms). rice field.

Production example of alkenyl succinic anhydride 542.4 g of alkylene compound (a), 157.2 g of maleic anhydride, and antioxidant "Chelex-O" (manufactured by SC Organic Chemical Co., Ltd.) were placed in a 1 L autoclave manufactured by Nitto Kouatsu Co., Ltd. , Triisooctyl phosphite) and 0.1 g of butyl hydroquinone as a polymerization inhibitor were charged, and pressurized nitrogen substitution (0.2 MPaG) was repeated three times. After stirring was started at 60°C, the temperature was raised to 230°C over 1 hour and the reaction was carried out for 6 hours. The pressure when reaching the reaction temperature was 0.3 MPaG. After completion of the reaction, the reaction mixture was cooled to 80°C, returned to normal pressure (101.3 kPa), and transferred to a 1 L four-necked flask. The temperature was raised to 180° C. with stirring, and the residual alkylene compound was distilled off at 1.3 kPa in 1 hour. Subsequently, after cooling to room temperature (25° C.), the pressure was returned to normal pressure (101.3 kPa) to obtain 406.1 g of the target alkenyl succinic anhydride A. The average molecular weight of alkenyl succinic anhydride A determined from the acid value was 268.

Core resin production example 1
Raw material monomers for polyester resin segments other than trimellitic anhydride shown in Tables 1 and 2, hydrocarbon wax (Paracol 6490: manufactured by Nippon Seiro Co., Ltd., Mn 800, melting point 76 ° C., acid value 18 mg KOH / g, hydroxyl value 97 mg KOH /g), the esterification catalyst and the esterification co-catalyst were placed in a 10-liter four-necked flask equipped with a dehydration tube equipped with a nitrogen inlet, a stirrer and a thermocouple, and heated to 235 ° C. under a nitrogen atmosphere. It was warmed and then polycondensed at 235° C. for 6 hours. After that, the temperature was lowered to 160° C., and a mixture of both reactive monomers, raw material monomers for the styrenic resin segment, and a polymerization initiator was added dropwise from a dropping funnel over 1 hour. After the dropwise addition, the addition polymerization reaction was aged for 1 hour while the temperature was maintained at 160°C, then the temperature was raised to 200°C and the pressure was reduced at 10 kPa for 1 hour. After that, the pressure was released, the temperature was lowered to 180°C, trimellitic anhydride shown in Tables 1 and 2 was added, the temperature was raised from 180°C to 210°C at a rate of 10°C/h, and then the reaction was carried out at 210°C for 1 hour. Furthermore, the reaction was carried out at 210° C. under a reduced pressure of 10 kPa to the softening points shown in Tables 1 and 2 to obtain amorphous composite resins (resins A1 to A6, A8 and A9). Physical properties are shown in Tables 1 and 2.

Core resin production example 2
Raw material monomers for the polyester resin segment other than trimellitic anhydride and fumaric acid shown in Table 2, hydrocarbon wax (Paracol 6490), esterification catalyst and esterification The mixture was placed in a 10-liter four-necked flask equipped with a thermocouple, heated to 235°C under a nitrogen atmosphere, and then polycondensed at 235°C for 6 hours. After that, the temperature was lowered to 180°C, trimellitic anhydride, fumaric acid, and a polymerization inhibitor shown in Table 2 were added, the temperature was raised from 180°C to 210°C at a rate of 10°C/h, and then the mixture was reacted at 210°C for 1 hour. let me Further, reaction was carried out at 210° C. under a reduced pressure of 10 kPa to the softening point shown in Table 2 to obtain an amorphous polyester resin (resin A7). Physical properties are shown in Table 2.

Core resin production example 3
Raw material monomers for the polyester resin segment other than trimellitic anhydride and fumaric acid shown in Table 2, hydrocarbon wax (Paracol 6490), esterification catalyst and esterification The mixture was placed in a 10-liter four-necked flask equipped with a thermocouple, heated to 235°C under a nitrogen atmosphere, and then polycondensed at 235°C for 6 hours. Thereafter, the temperature was lowered to 160° C., and a mixture of both reactive monomers, raw material monomers for the styrenic resin segment, and a polymerization initiator was added dropwise from a dropping funnel over 1 hour. After the dropwise addition, the addition polymerization reaction was aged for 1 hour while the temperature was maintained at 160°C, then the temperature was raised to 200°C and the pressure was reduced at 10 kPa for 1 hour. After that, the pressure was released, the temperature was lowered to 180°C, trimellitic anhydride, fumaric acid, and a polymerization inhibitor shown in Table 2 were added, and the temperature was raised from 180°C to 210°C at a rate of 10°C/h, and then at 210°C for 1 hour. reacted over time. Further, reaction was carried out at 210° C. under a reduced pressure of 10 kPa to the softening point shown in Table 2 to obtain an amorphous polyester resin (resin A10). Physical properties are shown in the table.

Core resin production example 4
Raw material monomers for the polyester resin segment other than trimellitic anhydride, fumaric acid and sebacic acid shown in Table 2, hydrocarbon wax (Paracol 6490), esterification catalyst, and esterification co-catalyst were added to a dehydration pipe equipped with a nitrogen inlet pipe. , was placed in a 10-liter four-necked flask equipped with a stirrer and a thermocouple, heated to 235°C under a nitrogen atmosphere, and then polycondensed at 235°C for 6 hours. Thereafter, the temperature was lowered to 160° C., and a mixture of both reactive monomers, raw material monomers for the styrenic resin segment, and a polymerization initiator was added dropwise from a dropping funnel over 1 hour. After the dropwise addition, the addition polymerization reaction was aged for 1 hour while the temperature was maintained at 160°C, then the temperature was raised to 200°C and the pressure was reduced at 10 kPa for 1 hour. After that, the pressure was released, the temperature was lowered to 180°C, trimellitic anhydride, fumaric acid, sebacic acid, and a polymerization inhibitor shown in Table 2 were added, the temperature was raised from 180°C to 210°C at a rate of 10°C/h, and then 210°C. °C for 1 hour. Furthermore, reaction was carried out at 210° C. under a reduced pressure of 10 kPa to the softening point shown in Table 2 to obtain an amorphous polyester resin (resin A11). Physical properties are shown in Table 2.

Core resin production example 5
The raw material monomers shown in Table 3 were placed in a 10 L four-necked flask equipped with a thermometer, stainless steel stirring rod, flow-down condenser and nitrogen inlet tube, and heated to 200°C in a nitrogen atmosphere in a mantle heater for 8 hours. The temperature was raised over a period of time. Thereafter, an esterification catalyst was added and the reaction was carried out at 8.0 kPa until the softening point shown in Table 3 was reached to obtain a crystalline polyester resin (resin C1). Physical properties are shown in Table 3.

Shell resin production example Raw material monomers other than trimellitic anhydride shown in Table 4, an esterification catalyst, and an esterification catalyst were added to four 10-liter containers equipped with a dehydration tube equipped with a nitrogen inlet tube, a stirrer, and a thermocouple. It was placed in a necked flask, heated to 235°C under a nitrogen atmosphere, and then polycondensed at 235°C for 6 hours. Thereafter, the temperature was lowered to 180°C, trimellitic anhydride shown in Table 4 was added, the temperature was raised from 180°C to 210°C at a rate of 10°C/h, and then the reaction was carried out at 210°C for 1 hour. Furthermore, the reaction was carried out at 210° C. under a reduced pressure of 10 kPa to the softening point shown in Table 4 to obtain amorphous polyester resins (resins B1 to B4). Physical properties are shown in Table 4.

Table 5 shows the analytical values of the metal species contained in the PET used in the production of the core resin and shell resin.

[Preparation of aqueous dispersion of resin particles containing core resin]
600 g of methyl ethyl ketone was charged into a 5 L container equipped with a stirrer, a reflux condenser, a dropping funnel, a thermometer and a nitrogen inlet tube, and 105 g (70 parts by mass) of Resin A and 45 g (30 parts by mass) of Resin C shown in Table 6 were mixed. ) was added at 60° C. and allowed to dissolve. A 5% by mass sodium hydroxide aqueous solution was added to the resulting solution so that the degree of neutralization would be 60 mol% relative to the acid value of the resin, and the mixture was stirred for 30 minutes to obtain a mixture. Subsequently 675 g of deionized water was added over 77 minutes. Next, while stirring at 250 r/min, methyl ethyl ketone is distilled off at a temperature of 50 ° C. or less under reduced pressure, and then the solid content concentration of the aqueous dispersion is measured. was adjusted to 20% by mass to obtain core resin particle dispersions X1 to X11.

[Preparation of Aqueous Dispersion of Resin Particles Containing Shell Resin]
Shell resin particle dispersions Z1 to Z4 were obtained in the same manner as in the preparation of core resin particle dispersion X1 except that 150 g of resin B shown in Table 7 was used in place of resin A1 and resin C1.

[Preparation of Release Agent Dispersion]
50 g of paraffin wax (manufactured by Nippon Seiro Co., Ltd., trade name: HNP0190, melting point: 85°C), 5 g of cationic surfactant (manufactured by Kao Corporation, trade name: Sansol B50), and 200 g of deionized water at 95°C , and the paraffin wax was dispersed using a homogenizer, followed by dispersion treatment using a pressure ejection homogenizer to obtain a release agent dispersion W1 containing release agent particles having a solid content concentration of 20% by mass. . The volume median particle size ( _D50 ) of the release agent particles was 550 nm.

[Preparation of colorant dispersion]
In a 1-liter beaker, add 116.2 g of copper phthalocyanine pigment "ECB-301" (manufactured by Dainichiseika Kogyo Co., Ltd.) and anionic surfactant "Neoperex (registered trademark) G-15" (manufactured by Kao Corporation). , 15 wt% sodium dodecylbenzenesulfonate aqueous solution) and 340 g of deionized water were mixed and dispersed for 3 hours at room temperature using a homogenizer. was added to obtain a colorant dispersion containing colorant particles. The volume median particle size ( _D50 ) of the colorant particles in the dispersion was 118 nm.

Examples 1-14 and Comparative Examples 1-4
500 g of the core resin particle dispersion shown in Tables 8 and 9, 49 g of the release agent dispersion, and the colorant dispersion were placed in a 3-liter four-necked flask equipped with a dehydration tube, a stirrer, and a thermocouple. was mixed with 3.3 g of 15% by mass sodium dodecylbenzenesulfonate aqueous solution "Neopelex G-15" (manufactured by Kao Corporation, anionic surfactant) at a temperature of 25°C. Next, while stirring the mixture, a solution prepared by adding 4.8% by mass aqueous potassium hydroxide solution to an aqueous solution of 40 g of ammonium sulfate dissolved in 570 g of deionized water to adjust the pH to 8.2 was added dropwise over 10 minutes. After that, the temperature was raised to 62° C. over 2 hours and maintained at 62° C. until the volume median particle diameter (D ₅₀ ) of the aggregated particles reached 5.9 μm to obtain a dispersion liquid of aggregated particles (I).
While maintaining the temperature of the dispersion of aggregated particles (I) obtained at 62° C., 60 g of the shell resin particle dispersion shown in Tables 8 and 9 was added dropwise at a rate of 0.6 mL/min (0.6 g/min). to obtain a dispersion of aggregated particles (II). The volume-median particle diameter ( _D50 ) of the aggregated particles (II) was 6.0 µm.
20 g of polyoxyethylene lauryl ether sodium polyoxyethylene lauryl ether sulfate "Emal E-27C" (manufactured by Kao Corporation, anionic surfactant, effective concentration: 27% by mass), deionized water were added to the resulting dispersion of aggregated particles (II). An aqueous solution obtained by mixing 280 g and 40 g of a 0.1 mol/L sulfuric acid aqueous solution was added. After that, the temperature was raised to 80° C. over 1 hour and maintained at 80° C. for 30 minutes, then 10 g of 0.1 mol/L sulfuric acid aqueous solution was added and further maintained at 80° C. for 15 minutes. Then, 15 g of a 0.1 mol/L sulfuric acid aqueous solution was added again, and the temperature was maintained at 80° C. until the circularity reached 0.970, thereby obtaining a dispersion of core-shell particles in which aggregated particles were fused.
The obtained core-shell particle dispersion was cooled to 30°C, and the dispersion was suction-filtered to separate solids, washed with deionized water at 25°C, and suction-filtered at 25°C for 2 hours. Thereafter, vacuum drying was performed at 33° C. for 24 hours using a vacuum constant temperature dryer “DRV622DA” (manufactured by ADVANTEC) to obtain toner particles (core-shell particles). The resulting toner particles had a particle size of 6.0 μm and a circularity of 0.970.
100 parts by mass of toner particles, 2.5 parts by mass of hydrophobic silica "RY50" (manufactured by Nippon Aerosil Co., Ltd., number average particle diameter: 40 nm), and hydrophobic silica "Cabosil (registered trademark) TS720" (manufactured by Cabot Japan Co., Ltd.) , number average particle diameter: 12 nm) was put in a Henschel mixer, stirred, and passed through a 150-mesh sieve to obtain a toner.

Test Example 1 [Durability of Toner]
Toner was mounted on a printing machine "Page Presto N-4" (manufactured by Casio Computer Co., Ltd., fixing: contact fixing method, development: non-magnetic one-component development method, development roll diameter: 2.3 cm), temperature 32°C, humidity A diagonal stripe pattern with a blackening rate of 5.5% was continuously printed under an environment of 85%. On the way, a solid black image was printed every 500 sheets, and the presence or absence of streaks on the image was checked. Printing was stopped when streaks appeared on the image, and printing was carried out up to 9000 sheets.
For the printing paper, high-quality paper "J paper A4 size" (manufactured by Fuji Xerox Co., Ltd.) was used for the toner of Examples and Comparative Examples other than Examples 7, 12, and 14. , 12, and 14, recycled PET-containing paper "Crisper" (manufactured by Toyobo Co., Ltd.) was used.
The number of printed sheets until streaks were visually observed on the image was defined as the number of sheets on which streaks were generated due to the fusion and adhesion of the toner to the developing roll, and the durability was evaluated. The results are shown in Tables 8 and 9. It can be determined that the greater the number of sheets without streaks, the higher the durability of the toner.

Test Example 2 [Toner Transfer Efficiency]
A solid image was printed by mounting the toner on a color printer "MICROLINE 5400" (trade name, manufactured by Oki Data Co., Ltd.).
For the printing paper, fine paper "J paper A4 size" (manufactured by Fuji Xerox Co., Ltd.) was used for the toner of Examples and Comparative Examples other than Examples 7, 12, and 14. , and 14, recycled PET-containing paper "Crisper" (manufactured by Toyobo Co., Ltd.) was used.
At this time, the amount of toner on the photoreceptor for the solid image was adjusted to 0.40 to 0.50 mg/cm ² , the machine was stopped halfway through the printing of the solid image, and mending tape was applied to the photoreceptor after passing through the section. Then, the untransferred toner remaining on the photoreceptor was transferred to a mending tape, and the mending tape was peeled off from the photoreceptor. The color difference between the peeled mending tape and the unused mending tape was measured with a color difference meter "X-Rite" (trade name, manufactured by X-Rite), and the transfer efficiency was evaluated based on the color difference density ΔE. . It should be noted that the smaller the numerical value, the better the transfer efficiency. The results are shown in Tables 8 and 9.

From the above results, it is clear that the toners of Examples 1-14 are all superior in durability as compared with Comparative Examples 1-4.
From the comparison between Example 1 and Example 8, it can be seen that the durability is further improved by using recycled PET for the core resin rather than for the shell resin. On the other hand, it can be seen that the transfer efficiency is improved by using the recycled PET as the shell resin.
From the comparison between Example 1 and Comparative Example 1, it can be seen that the use of recycled PET significantly improves durability compared to new PET.
From the comparison of Comparative Examples 1 and 2, even if a composite resin containing a large number of metal species is used instead of using recycled PET, the improvement in durability is slight. I understand.
From the comparison between Example 1 and Comparative Example 4, it can be seen that by using a composite resin as the core resin, the durability is improved more than that of the polyester resin.

The electrostatic charge image developing toner of the present invention is used for developing latent images formed by electrophotography, electrostatic recording, electrostatic printing and the like.

Claims (3)

A core-shell type toner for developing an electrostatic image, wherein the core comprises a polyester resin segment Pc, a styrene resin segment, and both polyester resin segments Pc and the styrene resin segment that bind together via covalent bonds. The shell contains a polyester-based resin containing a polyester resin segment Ps, and at least one of the polyester resin segment Pc and the polyester resin segment Ps is an alcohol A toner for electrostatic charge image development, which is a polycondensate of a component, a carboxylic acid component and recycled polyethylene terephthalate. Claim 1, wherein the content of recycled polyethylene terephthalate is 5 mol% or more and 75 mol% or less of the total amount of the alcohol component, the carboxylic acid component and the recycled polyethylene terephthalate, per 1 mol of the terephthalic acid-ethylene glycol unit. toner for developing electrostatic charge images. Step 1: a step of aggregating core resin particles containing a core resin in an aqueous medium to obtain aggregated particles (I);
Step 2: a step of aggregating shell resin particles containing a shell resin on the surface of the aggregated particles (I) obtained in step 1 to obtain aggregated particles (II); A method for producing a toner for developing an electrostatic charge image, comprising a step of fusing aggregated particles (II) thus obtained to obtain core-shell particles, wherein the core resin comprises a polyester resin segment Pc and a styrene resin segment and a structural unit derived from a bi-reactive monomer that bonds the polyester resin segment Pc and the styrenic resin segment via a covalent bond, and the shell resin contains the polyester resin segment Ps. Production of a toner for electrostatic charge image development containing a polyester resin, wherein at least one of the polyester resin segment Pc and the polyester resin segment Ps is a polycondensate of an alcohol component, a carboxylic acid component, and recycled polyethylene terephthalate. Method.