White toner for developing electrostatic images

Abstract

To provide a white toner for electrostatic charge image development which is excellent in low temperature fixability and durability.SOLUTION: A white toner for electrostatic charge image development contains toner particles containing a coloring agent containing a white pigment, and a binder resin, wherein the toner particles have a core-shell structure; the core part contains a polyester-based resin A containing a polycondensation product of an alcohol component ana a carboxylic acid component, and contains 60 mol% or more of a propylene oxide adduct of bisphenol A with respect to 100 mol% of the total alcohol component of a resin A; the shell part contains a polyester-based resin B containing a polycondensation product of an alcohol component ana a carboxylic acid component, and contains 10 mol% or more of the propylene oxide adduct of bisphenol A with respect to 100 mol% of the total alcohol component of a resin B; a mass ratio (binder resin of the core part / binder resin of the shell part) of the binder resin of the core part to the binder resin of the shell part is 78 / 22 or more to 95 / 5 or less, and the coloring agent is a titanium oxide coated with a polymer.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a white toner for developing electrostatic images, which is used for developing latent images formed in electrophotography, electrostatic recording, electrostatic printing and the like. [Background technology]

[0002] The diversification of print media has led to a demand for electrophotographic printing on print media other than paper. One of the main media is polypropylene film (hereinafter also referred to as "PP film") and polyethylene film (hereinafter also referred to as "PE film"), which are used for PET bottle labels and various packages. The heat resistance temperature of these films is not sufficiently high compared to the fixing temperature of toner, so there is a demand for improved low-temperature fixing ability of toner. On the other hand, there is an increasing demand for printing on recording media that are not white, such as colored paper and the above-mentioned resin films such as PP film and PE film. When printing on recording media that are not white, white toner is used for the purpose of expressing whiteness or forming a white background to enhance visibility.

[0003] Patent Document 1 describes a white toner for developing electrostatic images, which has toner particles containing a binder resin containing at least a crystalline polyester resin and an amorphous polyester resin and a white pigment for the purpose of suppressing light transmission through a white image, and has a loss tangent tanδ of 0.2 or more and 1.0 or less at 30°C as measured by dynamic viscoelasticity measurement. Furthermore, Patent Document 2 describes a white toner for developing electrostatic images, which contains a white colorant and a binder resin including an amorphous resin and a crystalline polyester resin, and the crystalline polyester resin contains at least a dicarboxylic acid component and two diol components having different carbon numbers as polymerization components, and is contained in an amount of 20% by mass to 50% by mass with respect to the entire binder resin, for the purpose of providing a white toner for developing electrostatic images that can produce white toner images in which the occurrence of image cracks is suppressed. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2019-113686 A [Patent Document 2] JP 2011-150257 A Summary of the Invention [Problem to be solved by the invention]

[0005] In the white toners described in Patent Documents 1 and 2, the uniform incorporation and dispersibility of titanium oxide in the toner are insufficient, and low-temperature fixability and durability are insufficient. The present invention relates to a white toner for developing electrostatic images, which has excellent low-temperature fixing properties and durability. [Means for solving the problem]

[0006] The present inventors have found that, in a white toner for developing electrostatic images containing toner particles having a core-shell structure, by using a specific colorant, using a specific polyester resin in the core and shell, and adjusting the amount of binder resin in the core and shell within a specific range, a white toner for developing electrostatic images having excellent low-temperature fixing properties and durability can be obtained. The present invention relates to the following [1]. [1] A white toner for developing electrostatic images, comprising toner particles containing a colorant containing a white pigment and a binder resin, the toner particles having a core-shell structure, the core portion containing a polyester resin A containing a polycondensate of an alcohol component and a carboxylic acid component, and containing 60 mol % or more of a propylene oxide adduct of bisphenol A relative to 100 mol % of the total alcohol components of resin A, the shell portion containing a polyester resin B containing a polycondensate of an alcohol component and a carboxylic acid component, and containing 10 mol % or more of a propylene oxide adduct of bisphenol A relative to 100 mol % of the total alcohol components of resin B, the mass ratio of the binder resin in the core portion to the binder resin in the shell portion (binder resin in the core portion / binder resin in the shell portion) being 78 / 22 or more and 95 / 5 or less, and the colorant being titanium oxide coated with a polymer. Effect of the Invention

[0007] According to the present invention, there is provided a white toner for developing electrostatic images, which has excellent low-temperature fixing properties and durability. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] [White toner for developing electrostatic images] The white toner for developing electrostatic images of the present invention (hereinafter, also simply referred to as "toner") is a white toner for developing electrostatic images comprising toner particles containing a colorant containing a white pigment and a binder resin, the toner particles having a core-shell structure, the core portion comprises a polyester resin A containing a polycondensate of an alcohol component and a carboxylic acid component, and contains 60 mol % or more of a propylene oxide adduct of bisphenol A relative to 100 mol % of the total alcohol components of resin A, the shell portion comprises a polyester resin B containing a polycondensate of an alcohol component and a carboxylic acid component, and contains 10 mol % or more of a propylene oxide adduct of bisphenol A relative to 100 mol % of the total alcohol components of resin B, the mass ratio of the binder resin of the core portion to the binder resin of the shell portion (binder resin of the core portion / binder resin of the shell portion) is 78 / 22 or more and 95 / 5 or less, and the colorant is titanium oxide coated with a polymer. The toner for developing electrostatic images of the present invention is excellent in low-temperature fixing property and durability. Here, durability means that the toner has excellent mechanical strength and maintains its core-shell structure even when stirred for a long period of time in a developing machine.

[0009] In the present invention, the alcohol component of the binder resin of the core part is mainly a propylene oxide adduct of bisphenol A, and the alcohol component of the binder resin of the shell part is also made to contain a propylene oxide adduct of bisphenol A. The ratio of the binder resin of the core part to the binder resin of the shell part is set within a specific range, and further, a white colorant in which titanium oxide, a white pigment, is coated with a polymer is used, thereby improving low-temperature fixability to a film label and simultaneously achieving durability. The reason for this is unclear, but it is believed that by using the same hydrophobic propylene oxide adduct of bisphenol A as the alcohol component of the binder resin of the core part and the shell part, the melting property of the core part and the shell part during fixation is improved, and affinity to the label is improved, so that fixation can be performed quickly at low temperatures. And, by using a white colorant in which titanium oxide, a white pigment, is coated with a polymer, the white pigment is captured with good dispersibility inside the core-shell toner particles, and the detachment of the white pigment from the toner particles can be suppressed, so that durability can be achieved even with a small amount of shell structure that is more advantageous for low-temperature fixability. The above-mentioned mechanism regarding the effect of the present invention is merely a presumption, and the present invention is not limited thereto.

[0010] The definitions of various terms used in this specification are given below. Whether a resin is crystalline or amorphous is determined by the crystallinity index. The crystallinity index is defined as the ratio of the softening point of the resin to the temperature of the maximum endothermic peak (softening point (°C) / maximum endothermic peak temperature (°C)) in the measurement method described in the examples below. A crystalline resin is one with a crystallinity index of 0.6 or more and 1.4 or less. An amorphous resin is one in which no endothermic peak is observed, or, if observed, has a crystallinity index of less than 0.6 or more than 1.4. The crystallinity index can be appropriately adjusted by the types and ratios of raw material monomers, as well as production conditions such as reaction temperature, reaction time, and cooling rate. With respect to hydrocarbon groups, the references "(iso or tertiary)" and "(iso)" in parentheses refer to both the cases with and without the prefixes present; the absence of the prefixes indicates normal. "(Meth)acrylic acid" means at least one selected from acrylic acid and methacrylic acid. "(Meth)acrylate" means at least one selected from acrylate and methacrylate. The "(meth)acryloyl group" means at least one selected from an acryloyl group and a methacryloyl group. The term "toner particles" refers to toner base particles excluding external additives from the toner. The present invention will be described below by taking this embodiment as an example.

[0011] [Toner Particles] In the present embodiment, the toner particles contain a colorant containing a white pigment and a binder resin, and have a core-shell structure. The core portion contains a polyester-based resin A (hereinafter simply referred to as "resin A") containing a polycondensate of an alcohol component and a carboxylic acid component as a binder resin, and contains 60 mol % or more of a propylene oxide adduct of bisphenol A relative to 100 mol % of the total alcohol component of resin A. The shell portion contains, as a binder resin, a polyester-based resin B (hereinafter also referred to simply as "resin B") that includes a polycondensate of an alcohol component and a carboxylic acid component, and contains 10 mol % or more of a propylene oxide adduct of bisphenol A relative to 100 mol % of the total alcohol components of resin B. The core preferably contains, as a binder resin, a crystalline polyester resin C (hereinafter, simply referred to as "resin C") in addition to the above-mentioned resin A. The core preferably contains, in addition to the binder resin, a colorant containing a white pigment, and further contains a release agent. In addition, the core may contain additives such as a charge control agent, a magnetic powder, a flowability improver, a conductivity adjuster, a reinforcing filler such as a fibrous substance, an antioxidant, an antiaging agent, and a cleaning property improver.

[0012] <Amorphous polyester resin A (resin A)> The amorphous polyester resin A is, for example, an amorphous polyester resin containing a polycondensate of an alcohol component and a carboxylic acid component. Examples of the amorphous polyester resin include polyester resin and modified polyester resin. Examples of the modified polyester resin include urethane modified polyester resin, epoxy modified polyester resin, and composite resin containing polyester resin segment and addition polymerization resin segment. Among these, it is preferable to use amorphous composite resin A containing polyester resin segment which is a polycondensation product of alcohol component and carboxylic acid component, and addition polymerization resin segment which is an addition polymerization product of raw material monomer containing styrene compound.

[0013] From the viewpoint of achieving both improved low-temperature fixability and durability, the amorphous composite resin (hereinafter also simply referred to as "composite resin A") preferably contains a polyester resin segment, an addition polymerization resin segment which is an addition polymerization product of raw material monomers including a styrene-based compound, and a structural unit derived from a bireactive monomer bonded to the polyester resin segment and the addition polymerization resin segment via a covalent bond. From the viewpoint of achieving both improved low-temperature fixability and durability, the composite resin A preferably further contains a structural unit derived from a hydrocarbon wax having at least one of a carboxy group and a hydroxyl group (hereinafter also referred to as "hydrocarbon wax WA").

[0014] The polyester resin segment is composed of a polycondensate of an alcohol component and a carboxylic acid component. Examples of the alcohol component include aromatic diols, alkylene oxide adducts of aromatic diols, linear or branched aliphatic diols, alicyclic diols, and trihydric or higher polyhydric alcohols. Among these, alkylene oxide adducts of aromatic diols are preferred.

[0015] The alkylene oxide adduct of an aromatic diol is preferably an alkylene oxide adduct of bisphenol A, more preferably an alkylene oxide adduct of formula (I): [ka] (In the formula, OR 1 and R 2 O is an oxyalkylene group, and R 1 and R 2 each independently represents an ethylene group or a propylene group, x and y represent the average number of moles of alkylene oxide added and are each positive numbers, and the sum of x and y is 1 or more, preferably 1.5 or more, and 16 or less, preferably 8 or less, and more preferably 4 or less.

[0016] Examples of the alkylene oxide adduct of bisphenol A include a propylene oxide adduct of bisphenol A [2,2-bis(4-hydroxyphenyl)propane] and an ethylene oxide adduct of bisphenol A. These may be used alone or in combination. Among these, the propylene oxide adduct of bisphenol A is preferred. From the viewpoint of low-temperature fixing property and durability, Resin A and Composite Resin A contain 60 mol% or more of a propylene oxide adduct of bisphenol A relative to 100 mol% of the alcohol component, preferably 70 mol% or more, more preferably 90 mol% or more, even more preferably 95 mol% or more, and 100 mol% or less, even more preferably 100 mol%.

[0017] Examples of linear or branched aliphatic diols include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 2,2-dimethyl-1,3-propanediol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, and 1,12-dodecanediol. Examples of alicyclic diols include hydrogenated bisphenol A [2,2-bis(4-hydroxycyclohexyl)propane] and adducts of hydrogenated bisphenol A with alkylene oxides having 2 to 4 carbon atoms (average number of moles added: 2 to 12). Examples of trihydric or higher polyhydric alcohols include glycerin, pentaerythritol, trimethylolpropane, and sorbitol. These alcohol components may be used alone or in combination of two or more.

[0018] Examples of the carboxylic acid component include dicarboxylic acids and polycarboxylic acids having three or more carboxylic acids. Examples of dicarboxylic acids include aromatic dicarboxylic acids, linear or branched aliphatic dicarboxylic acids, and alicyclic dicarboxylic acids. Among these, at least one selected from aromatic dicarboxylic acids and linear or branched aliphatic dicarboxylic acids is preferred. Examples of aromatic dicarboxylic acids include phthalic acid, isophthalic acid, and terephthalic acid. Among these, isophthalic acid and terephthalic acid are preferred, and terephthalic acid is more preferred. The amount of aromatic dicarboxylic acid in the carboxylic acid component is preferably 20 mol% or more, more preferably 30 mol% or more, even more preferably 50 mol% or more, and is preferably 90 mol% or less, more preferably 80 mol% or less, even more preferably 70 mol% or less.

[0019] The linear or branched aliphatic dicarboxylic acid preferably has 2 or more, more preferably 3 or more, and preferably has 30 or less, more preferably 20 or less. Examples of linear or branched aliphatic dicarboxylic acids include oxalic acid, malonic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, succinic acid, adipic acid, sebacic acid, dodecanedioic acid, azelaic acid, and succinic acid substituted with a hydrocarbon group having 1 to 20 carbon atoms. Examples of succinic acid substituted with a hydrocarbon group having 1 to 20 carbon atoms include dodecylsuccinic acid, dodecenylsuccinic acid, and octenylsuccinic acid. Among these, fumaric acid and sebacic acid are preferred. The amount of linear or branched aliphatic dicarboxylic acid in the carboxylic acid component is preferably 1 mol % or more, more preferably 10 mol % or more, even more preferably 20 mol % or more, and is preferably 50 mol % or less, more preferably 40 mol % or less.

[0020] The trivalent or higher polyvalent carboxylic acid is preferably a trivalent carboxylic acid, such as trimellitic acid. When a trivalent or higher polycarboxylic acid is contained, the amount of the trivalent or higher polycarboxylic acid in the carboxylic acid component is preferably 3 mol% or more, more preferably 5 mol% or more, even more preferably 8 mol% or more, and is preferably 30 mol% or less, more preferably 20 mol% or less, even more preferably 15 mol% or less. These carboxylic acid components may be used alone or in combination of two or more.

[0021] The equivalent ratio of the carboxyl groups of the carboxylic acid component to the hydroxyl groups of the alcohol component [COOH groups / OH groups] is preferably 0.7 or more, more preferably 0.8 or more, and is preferably 1.3 or less, more preferably 1.2 or less.

[0022] The addition polymerized resin segment is an addition polymer of raw material monomers containing a styrene-based compound, from the viewpoint of obtaining a toner having excellent low-temperature fixing property and durability. The styrene-based compound may be unsubstituted or substituted styrene. Examples of the substituent on styrene include an alkyl group having 1 to 5 carbon atoms, a halogen atom, an alkoxy group having 1 to 5 carbon atoms, a sulfo group, or a salt thereof. Examples of styrene-based compounds include styrene, methylstyrene, α-methylstyrene, β-methylstyrene, tert-butylstyrene, chlorostyrene, chloromethylstyrene, methoxystyrene, styrenesulfonic acid, and salts thereof. Among these, styrene is preferred. The content of the styrene-based compound in the raw material monomers of the addition polymerization resin segment is preferably 50% by mass or more, more preferably 65% ​​by mass or more, even more preferably 70% by mass or more, and is 100% by mass or less, preferably 95% by mass or less, more preferably 90% by mass or less, even more preferably 85% by mass or less.

[0023] Examples of raw material monomers other than styrene-based compounds include (meth)acrylic acid esters such as alkyl (meth)acrylate, benzyl (meth)acrylate, and dimethylaminoethyl (meth)acrylate; olefins such as ethylene, propylene, and butadiene; halovinyls such as vinyl chloride; vinyl esters such as vinyl acetate and vinyl propionate; vinyl ethers such as vinyl methyl ether; vinylidene halides such as vinylidene chloride; and N-vinyl compounds such as N-vinylpyrrolidone. Among these, (meth)acrylic acid esters are preferred, and alkyl (meth)acrylates are more preferred. From the viewpoint of achieving both improved low-temperature fixability and durability, the number of carbon atoms in the alkyl group in the alkyl (meth)acrylate is preferably 1 or more, more preferably 4 or more, even more preferably 6 or more, and is preferably 24 or less, more preferably 22 or less, even more preferably 20 or less. Examples of the alkyl (meth)acrylate include methyl (meth)acrylate, ethyl (meth)acrylate, (iso)propyl (meth)acrylate, (iso or tertiary)butyl (meth)acrylate, (iso)amyl (meth)acrylate, cyclohexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, (iso)octyl (meth)acrylate, (iso)decyl (meth)acrylate, (iso)dodecyl (meth)acrylate, (iso)palmityl (meth)acrylate, (iso)stearyl (meth)acrylate, and (iso)behenyl (meth)acrylate. Among these, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, dodecyl (meth)acrylate, and stearyl (meth)acrylate are preferred, and stearyl (meth)acrylate is more preferred.

[0024] In the raw material monomers of the addition polymerization resin segment, the content of the (meth)acrylic acid ester is preferably 5 mass% or more, more preferably 10 mass% or more, even more preferably 15 mass% or more, and preferably 50 mass% or less, more preferably 40 mass% or less, even more preferably 30 mass% or less.

[0025] The total amount of the styrene-based compound and the (meth)acrylic acid ester in the raw material monomers of the addition polymerization resin segment is preferably 80 mass % or more, more preferably 90 mass % or more, even more preferably 95 mass % or more, and even more preferably 100 mass %.

[0026] The composite resin A has a constitutional unit derived from a bireactive monomer bonded to a polyester resin segment and an addition polymerization resin segment via a covalent bond. The term "structural unit derived from a bireactive monomer" refers to a unit formed by reaction of the functional group and the unsaturated bond site of a bireactive monomer. Examples of the bireactive monomer include addition polymerizable monomers having at least one functional group selected from a hydroxyl group, a carboxyl group, an epoxy group, a primary amino group, and a secondary amino group in the molecule. Among these, from the viewpoint of reactivity, addition polymerizable monomers having at least one functional group selected from a hydroxyl group and a carboxyl group are preferred, and addition polymerizable monomers having a carboxyl group are more preferred. Examples of the addition polymerizable monomer having a carboxy group include acrylic acid, methacrylic acid, fumaric acid, and maleic acid. Among these, from the viewpoint of reactivity in both the polycondensation reaction and the addition polymerization reaction, acrylic acid and methacrylic acid are preferred, and acrylic acid is more preferred. The amount of the constitutional units derived from the bireactive monomer is preferably 1 mol part or more, more preferably 5 mol parts or more, even more preferably 10 mol parts or more, and is preferably 30 mol parts or less, more preferably 25 mol parts or less, even more preferably 20 mol parts or less, relative to 100 mol parts of the alcohol component of the polyester resin segment of the composite resin A.

[0027] The component derived from the hydrocarbon wax WA is, for example, the hydrocarbon wax WA in which a hydroxyl group or a carboxyl group has reacted and is covalently bonded to a polyester resin segment. The hydrocarbon wax WA has at least one of a carboxyl group and a hydroxyl group. The hydrocarbon wax WA may have either a hydroxyl group or a carboxyl group, or both, but preferably has a hydroxyl group and a carboxyl group from the viewpoint of achieving both an improvement in low-temperature fixability and durability. The hydrocarbon wax WA can be obtained, for example, by modifying an unmodified hydrocarbon wax by a known method. Examples of raw materials for the hydrocarbon wax WA include paraffin wax, Fischer-Tropsch wax, microcrystalline wax, polyethylene wax, and polypropylene wax. Among these, paraffin wax and Fischer-Tropsch wax are preferred.

[0028] Commercially available examples of hydrocarbon waxes having hydroxyl groups include "Unilin 700," "Unilin 425," and "Unilin 550" (all manufactured by Baker Petrolite).

[0029] An example of a commercially available product of a hydrocarbon wax having a carboxy group is maleic anhydride modified ethylene-propylene copolymer "HIWAX 1105A" (manufactured by Mitsui Chemicals, Inc.).

[0030] Commercially available examples of hydrocarbon waxes having a hydroxyl group and a carboxyl group include "PARACOL 6420", "PARACOL 6470", and "PARACOL 6490" (all manufactured by Nippon Seiro Co., Ltd.).

[0031] The hydroxyl value of the hydrocarbon wax WA is preferably 35 mgKOH / g or more and preferably 180 mgKOH / g or less, from the viewpoint of achieving both improved low-temperature fixability and durability. The acid value of the hydrocarbon wax WA is preferably 1 mgKOH / g or more and preferably 30 mgKOH / g or less, from the viewpoint of achieving both improved low-temperature fixability and durability. The total of the hydroxyl value and the acid value of the hydrocarbon wax WA is preferably 35 mgKOH / g or more and 210 mgKOH / g or less, from the viewpoint of achieving both improved low-temperature fixability and durability.

[0032] The number average molecular weight of the hydrocarbon wax WA is preferably 500 or more and preferably 2000 or less, from the viewpoint of achieving both an improvement in low-temperature fixability and durability. The hydroxyl value and acid value of the hydrocarbon wax WA are measured by the method described in the Examples. The number average molecular weight of the hydrocarbon wax WA is measured by gel permeation chromatography using chloroform as a solvent and polystyrene as a standard substance.

[0033] The content of the polyester resin segment in the composite resin A is preferably 40% by mass or more, more preferably 45% by mass or more, and even more preferably 50% by mass or more, and is preferably 90% by mass or less, more preferably 85% by mass or less, even more preferably 75% by mass or less, and even more preferably 70% by mass or less, based on the total amount of the polyester resin segment and the addition polymerization resin segment. Note that the constitutional unit derived from the bireactive monomer is included in the calculation of the polyester resin segment.

[0034] The content of the addition polymerization resin segment in the composite resin A is preferably 10% by mass or more, more preferably 15% by mass or more, and even more preferably 25% by mass or more, and is preferably 60% by mass or less, more preferably 55% by mass or less, and even more preferably 45% by mass or less, based on the total amount of the polyester resin segment and the addition polymerization resin segment. Note that the constitutional unit derived from the bireactive monomer is calculated by including it in the polyester resin segment.

[0035] The amount of the constitutional units derived from the bireactive monomer in the composite resin A is preferably 0.1 mass% or more, more preferably 0.5 mass% or more, even more preferably 0.8 mass% or more, and is preferably 10 mass% or less, more preferably 5 mass% or less, even more preferably 3 mass% or less, based on the total amount of the polyester resin segment and the addition polymerization resin segment.

[0036] The amount of structural units derived from the hydrocarbon wax WA in the composite resin A is preferably 0.1 parts by mass or more, more preferably 0.5 parts by mass or more, even more preferably 1 part by mass or more, even more preferably 3 parts by mass or more, relative to 100 parts by mass of the total amount of the polyester resin segment and the addition polymerization resin segment, and is preferably 10 parts by mass or less, more preferably 8 parts by mass or less, even more preferably 6 parts by mass or less.

[0037] In the composite resin A, the total amount of the polyester resin segment, the addition polymerization resin segment, the constitutional units derived from the bireactive monomer, and the constitutional units derived from the hydrocarbon wax WA is preferably 80 mass% or more, more preferably 90 mass% or more, even more preferably 95 mass% or more, and is 100 mass% or less, more preferably 100 mass%.

[0038] The above amount is calculated based on the ratio of the amounts of the polyester resin segment, raw material monomer for the addition polymerization resin segment, bireactive monomer, structural unit derived from the hydrocarbon wax WA, and radical polymerization initiator, and does not include the amount of dehydration due to polycondensation in the polyester resin segment, etc. When a radical polymerization initiator is used, the mass of the radical polymerization initiator is included in the calculation of the addition polymerization resin segment.

[0039] The composite resin A may be produced, for example, by a method including a step A of carrying out a polycondensation reaction between an alcohol component and a carboxylic acid component, and a step B of carrying out an addition polymerization reaction between a raw material monomer of the addition polymerization resin segment and a bireactive monomer. When the composite resin A has a structural unit derived from a hydrocarbon wax WA, in the above-mentioned step A, for example, a polycondensation reaction of an alcohol component and a carboxylic acid component is carried out in the presence of a hydrocarbon wax WA having at least one of a hydroxyl group and a carboxyl group. Step B may be carried out after step A, step B may be carried out after step A, or step A and step B may be carried out simultaneously. In the step A, a part of the carboxylic acid component is subjected to a polycondensation reaction, and then the step B is carried out, and thereafter the remainder of the carboxylic acid component is added to the polymerization system, and the polycondensation reaction of the step A and the reaction with the bireactive monomer, if necessary, are further promoted.

[0040] In step A, if necessary, polycondensation may be performed using an esterification catalyst such as tin(II) di(2-ethylhexanoate), dibutyltin oxide, titanium diisopropylate bistriethanolamine, etc., in an amount of 0.01 part by mass or more and 5 parts by mass or less per 100 parts by mass of the total amount of the alcohol component and the carboxylic acid component; or an esterification promoter such as gallic acid (same as 3,4,5-trihydroxybenzoic acid), etc., in an amount of 0.001 part by mass or more and 0.5 part by mass or less per 100 parts by mass of the total amount of the alcohol component and the carboxylic acid component. In addition, when a monomer having an unsaturated bond such as fumaric acid is used in the polycondensation reaction, a radical polymerization inhibitor may be used, if necessary, in an amount of preferably 0.001 to 0.5 parts by mass per 100 parts by mass of the total amount of the alcohol component and the carboxylic acid component. An example of the radical polymerization inhibitor is 4-tert-butylcatechol. The temperature of the polycondensation reaction is preferably 120° C. or higher, more preferably 160° C. or higher, and even more preferably 180° C. or higher, and is preferably 250° C. or lower, more preferably 240° C. or lower. The polycondensation may be carried out in an inert gas atmosphere.

[0041] Examples of the polymerization initiator for the addition polymerization reaction include peroxides such as dibutyl peroxide, persulfates such as sodium persulfate, and azo compounds such as 2,2'-azobis(2,4-dimethylvaleronitrile). The amount of the radical polymerization initiator used is preferably 1 part by mass or more and 20 parts by mass or less based on 100 parts by mass of the raw material monomer of the addition polymerization resin segment. The temperature of the addition polymerization reaction is preferably 110° C. or higher, more preferably 130° C. or higher, even more preferably 150° C. or higher, and is preferably 220° C. or lower, more preferably 210° C. or lower.

[0042] (Physical properties of resin A) The softening point of Resin A is preferably 70° C. or higher, more preferably 80° C. or higher, and even more preferably 90° C. or higher, and is preferably 140° C. or lower, and more preferably 120° C. or lower. The glass transition temperature of resin A is preferably 30° C. or higher, more preferably 40° C. or higher, and preferably 80° C. or lower, more preferably 70° C. or lower.

[0043] The acid value of Resin A is preferably 5 mgKOH / g or more, more preferably 10 mgKOH / g or more, and is preferably 40 mgKOH / g or less, more preferably 35 mgKOH / g or less. The softening point, glass transition temperature, and acid value of Resin A can be appropriately adjusted by the type and amount of raw material monomer used, as well as production conditions such as reaction temperature, reaction time, and cooling rate, and these values ​​can be determined by the methods described in the examples. When two or more types of composite resin A are used in combination, it is preferable that the softening point, glass transition temperature and acid value of the mixture obtained are each within the above-mentioned ranges.

[0044] <Crystalline polyester resin C> In the present invention, from the viewpoint of obtaining a toner having excellent low-temperature fixing property, the core preferably contains the crystalline polyester resin C as a binder resin. The crystalline polyester resin C is, for example, a crystalline polyester resin which is a polycondensation product of an alcohol component and a carboxylic acid component. The alcohol component is preferably an α,ω-aliphatic diol. The α,ω-aliphatic diol has preferably 2 or more, more preferably 4 or more, even more preferably 6 or more, and preferably 16 or less, more preferably 14 or less, even more preferably 12 or less. Examples of α,ω-aliphatic diols include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, and 1,14-tetradecanediol. Among these, 1,4-butanediol, 1,6-hexanediol, 1,8-octanediol, 1,10-decanediol, and 1,12-dodecanediol are preferred, and 1,10-decanediol is more preferred.

[0045] The amount of the α,ω-aliphatic diol in the alcohol component is preferably 80 mol % or more, more preferably 90 mol % or more, even more preferably 95 mol % or more, and is 100 mol % or less, even more preferably 100 mol %.

[0046] The alcohol component may contain other alcohol components different from the α,ω-aliphatic diol. Examples of the other alcohol components include aliphatic diols other than α,ω-aliphatic diols, such as 1,2-propanediol and neopentyl glycol; aromatic diols, such as alkylene oxide adducts of bisphenol A; and trihydric or higher alcohols, such as glycerin, pentaerythritol, and trimethylolpropane. These alcohol components may be used alone or in combination.

[0047] The carboxylic acid component is preferably an aliphatic dicarboxylic acid, more preferably a straight-chain aliphatic dicarboxylic acid. The aliphatic dicarboxylic acid has preferably 4 or more, more preferably 8 or more, and even more preferably 10 or more carbon atoms, and preferably 14 or less, and more preferably 12 or less. Examples of the aliphatic dicarboxylic acid include fumaric acid, sebacic acid, dodecanedioic acid, and tetradecanedioic acid. Among these, sebacic acid and tetradecanedioic acid are preferred, and sebacic acid is more preferred. These carboxylic acid components may be used alone or in combination.

[0048] The amount of the aliphatic dicarboxylic acid in the carboxylic acid component is preferably 80 mol % or more, more preferably 90 mol % or more, even more preferably 95 mol % or more, and is 100 mol % or less, even more preferably 100 mol %.

[0049] The carboxylic acid component may contain other carboxylic acid components different from the aliphatic dicarboxylic acid. Examples of other carboxylic acid components include aromatic dicarboxylic acids such as terephthalic acid and isophthalic acid, and polyvalent carboxylic acids having three or more carboxylic acids. These carboxylic acid components may be used alone or in combination.

[0050] The equivalent ratio of the carboxyl groups of the carboxylic acid component to the hydroxyl groups of the alcohol component [COOH groups / OH groups] is preferably 0.7 or more, more preferably 0.8 or more, and is preferably 1.3 or less, more preferably 1.2 or less.

[0051] The crystalline polyester resin C is produced, for example, by a method of polycondensing an alcohol component and a carboxylic acid component. During polycondensation, if necessary, an esterification catalyst such as tin(II) di(2-ethylhexanoate), dibutyltin oxide, or titanium diisopropoxybis(triethanolaminate) may be used in an amount of 0.01 part by mass or more and 5 parts by mass or less per 100 parts by mass of the total amount of the alcohol component and the carboxylic acid component; or an esterification promoter such as gallic acid (same as 3,4,5-trihydroxybenzoic acid) may be used in an amount of 0.001 part by mass or more and 0.5 part by mass or less per 100 parts by mass of the total amount of the alcohol component and the carboxylic acid component. When a monomer having an unsaturated bond such as fumaric acid is used in polycondensation, a radical polymerization inhibitor may be used, if necessary, in an amount of preferably 0.001 to 0.5 parts by mass per 100 parts by mass of the total amount of the alcohol component and the carboxylic acid component. An example of the radical polymerization inhibitor is 4-tert-butylcatechol. The temperature of the polycondensation reaction is preferably 120° C. or higher, more preferably 160° C. or higher, and even more preferably 180° C. or higher, and is preferably 250° C. or lower, more preferably 240° C. or lower. The polycondensation may be carried out in an inert gas atmosphere.

[0052] (Physical properties of crystalline polyester resin C) The softening point of the crystalline polyester resin C is preferably 60°C or higher, more preferably 70°C or higher, and even more preferably 80°C or higher from the viewpoint of the storage stability of the toner, and is preferably 150°C or lower, more preferably 120°C or lower, and even more preferably 100°C or lower from the viewpoint of further improving the low-temperature fixing ability. The melting point of the crystalline polyester resin C is preferably 50°C or higher, more preferably 60°C or higher, and even more preferably 70°C or higher from the viewpoint of the storage stability of the toner, and is preferably 100°C or lower, more preferably 90°C or lower, and even more preferably 85°C or lower from the viewpoint of further improving the low-temperature fixing ability.

[0053] The acid value of the crystalline polyester resin C is preferably 5 mgKOH / g or more, more preferably 10 mgKOH / g or more, and is preferably 35 mgKOH / g or less, more preferably 25 mgKOH / g or less.

[0054] The softening point, melting point and acid value of the crystalline polyester resin C can be appropriately adjusted by the type and amount of the raw material monomer, as well as production conditions such as reaction temperature, reaction time and cooling rate, and are determined by the method described in the Examples below. When two or more types of crystalline polyester resin C are used in combination, it is preferable that the softening point, melting point and acid value obtained as a mixture thereof are each within the above-mentioned ranges.

[0055] When crystalline polyester C is used for the core portion, the mass ratio of amorphous polyester resin A to crystalline polyester resin C [amorphous polyester resin A / crystalline polyester resin C] is preferably 40 / 60 or more, more preferably 60 / 40 or more, even more preferably 65 / 35 or more, and is preferably 95 / 5 or less, more preferably 90 / 10 or less, even more preferably 85 / 15 or less. In the binder resin of the core portion, the total amount of the amorphous polyester resin A and the crystalline polyester resin C is preferably 60% by mass or more, more preferably 80% by mass or more, even more preferably 90% by mass or more, even more preferably 95% by mass or more, and is 100% by mass or less, even more preferably 100% by mass.

[0056] <Amorphous polyester resin B (resin B)> The shell portion of the toner particle contains an amorphous polyester resin (resin B). The amorphous polyester resin (resin B) is, for example, an amorphous polyester resin containing a polycondensate of an alcohol component and a carboxylic acid component. Examples of the amorphous polyester resin include polyester resin and modified polyester resin. Examples of the modified polyester resin include urethane modified polyester resin, epoxy modified polyester resin, and composite resin containing polyester resin segment and addition polymerization resin segment. Among these, it is preferable to use a polyester resin which is a polycondensation product of an alcohol component and a carboxylic acid component, or a polyester resin segment which is a polycondensation product of an alcohol component and a carboxylic acid component, and an amorphous composite resin which is an addition polymerization product of a raw material monomer containing a styrene compound, and more preferable to use a polyester resin which is a polycondensation product of an alcohol component and a carboxylic acid component.

[0057] Examples of the alcohol component include alkylene oxide adducts of aromatic diols, linear or branched aliphatic diols, alicyclic diols, and trihydric or higher polyhydric alcohols. Among these, alkylene oxide adducts of aromatic diols are preferred from the viewpoint of both improving low-temperature fixability and durability. Examples of alkylene oxide adducts of aromatic diols include the same ones as those exemplified for resin A.

[0058] From the viewpoint of achieving both improved low-temperature fixability and durability, resin B contains 10 mol % or more of a propylene oxide adduct of bisphenol A relative to 100 mol % of the alcohol component. Examples of the alkylene oxide adduct of bisphenol A include a propylene oxide adduct of bisphenol A [2,2-bis(4-hydroxyphenyl)propane] and an ethylene oxide adduct of bisphenol A. These may be used alone or in combination. Among these, it is preferable to use a propylene oxide adduct of bisphenol A and an ethylene oxide adduct of bisphenol A in combination. From the viewpoint of obtaining a toner having excellent low-temperature fixing properties, the content of the propylene oxide adduct of bisphenol A is 10 mol % or more, preferably 15 mol % or more, more preferably 20 mol % or more, and even more preferably 25 mol % or more, relative to 100 mol % of the alcohol component, and from the viewpoint of obtaining a toner having excellent durability, the content is 100 mol % or less, preferably 90 mol % or less, more preferably 70 mol % or less, and even more preferably 60 mol % or less. The content of the ethylene oxide adduct of bisphenol A is, from the viewpoint of obtaining a toner having excellent durability, 0 mol % or more, preferably 10 mol % or more, more preferably 30 mol % or more, and even more preferably 40 mol % or more, relative to 100 mol % of the alcohol component, and from the viewpoint of obtaining a toner having excellent low-temperature fixing property, it is 90 mol % or less, preferably 85 mol % or less, more preferably 80 mol % or less, and even more preferably 75 mol % or less. The content of the alkylene oxide adduct of bisphenol A is 10 mol% or more, preferably 40 mol% or more, more preferably 90 mol% or more, even more preferably 95 mol% or more, and is 100 mol% or less, even more preferably 100 mol%, based on 100 mol% of the alcohol component.

[0059] As the linear or branched aliphatic diol, alicyclic diol, and trihydric or higher polyhydric alcohol, those exemplified for the resin A above can be mentioned. These alcohol components may be used alone or in combination of two or more.

[0060] Examples of the carboxylic acid component include dicarboxylic acids and polycarboxylic acids having three or more carboxylic acids. Examples of dicarboxylic acids include aromatic dicarboxylic acids, linear or branched aliphatic dicarboxylic acids, and alicyclic dicarboxylic acids. Among these, at least one selected from aromatic dicarboxylic acids and linear or branched aliphatic dicarboxylic acids is preferred. Examples of the aromatic dicarboxylic acid include those exemplified above for Resin A. Among these, isophthalic acid and terephthalic acid are preferred, and terephthalic acid is more preferred. The amount of aromatic dicarboxylic acid in the carboxylic acid component is preferably 20 mol% or more, more preferably 30 mol% or more, even more preferably 40 mol% or more, even more preferably 50 mol% or more, even more preferably 60 mol% or more, and is preferably 95 mol% or less, more preferably 90 mol% or less, even more preferably 85 mol% or less.

[0061] Examples of linear or branched aliphatic dicarboxylic acids include those exemplified above for resin A. Among these, fumaric acid, sebacic acid, adipic acid, and succinic acid substituted with an aliphatic hydrocarbon group having 1 to 20 carbon atoms are preferred, and adipic acid and succinic acid substituted with an aliphatic hydrocarbon group having 1 to 20 carbon atoms are more preferred. The amount of linear or branched aliphatic dicarboxylic acid in the carboxylic acid component is preferably 1 mol% or more, more preferably 3 mol% or more, even more preferably 5 mol% or more, and preferably 80 mol% or less, more preferably 60 mol% or less, even more preferably 50 mol% or less, even more preferably 40 mol% or less.

[0062] Examples of the trivalent or higher polyvalent carboxylic acid include those exemplified above for resin A. Trimellitic acid or its anhydride is preferred. When a trivalent or higher polycarboxylic acid is contained, the amount of the trivalent or higher polycarboxylic acid in the carboxylic acid component is preferably 3 mol% or more, more preferably 5 mol% or more, even more preferably 8 mol% or more, and is preferably 30 mol% or less, more preferably 20 mol% or less, even more preferably 15 mol% or less. These carboxylic acid components may be used alone or in combination of two or more.

[0063] The equivalent ratio of the carboxyl groups of the carboxylic acid component to the hydroxyl groups of the alcohol component [COOH groups / OH groups] is preferably 0.7 or more, more preferably 0.8 or more, and is preferably 1.3 or less, more preferably 1.2 or less.

[0064] Resin B may be produced, for example, by step A in which an alcohol component and a carboxylic acid component are polycondensed, or, when resin B is a composite resin, by a method including step A and step B in which raw material monomers of an addition polymerization resin segment and a bireactive monomer are addition polymerized. Steps A and B are the same as those exemplified for resin A, and the preferred ranges are also the same.

[0065] (Physical properties of resin B) From the viewpoint of storage stability, the softening point of Resin B is preferably 70°C or higher, more preferably 90°C or higher, and even more preferably 100°C or higher, and from the viewpoint of further improving low-temperature fixability, it is preferably 150°C or lower, more preferably 140°C or lower, and even more preferably 125°C or lower. From the viewpoint of storage stability, the glass transition temperature of Resin B is preferably 30° C. or higher, more preferably 40° C. or higher, and even more preferably 50° C. or higher, and from the viewpoint of further improving low-temperature fixability, it is preferably 80° C. or lower, more preferably 75° C. or lower, and even more preferably 70° C. or lower.

[0066] The acid value of Resin B is preferably 5 mgKOH / g or more, more preferably 10 mgKOH / g or more, even more preferably 15 mgKOH / g or more, and preferably 40 mgKOH / g or less, more preferably 35 mgKOH / g or less, even more preferably 30 mgKOH / g or less. The softening point, glass transition temperature, and acid value of Resin B can be appropriately adjusted by the types and amounts of raw material monomers used, as well as production conditions such as reaction temperature, reaction time, and cooling rate, and these values ​​can be determined by the methods described in the examples. When two or more resins B are used in combination, the softening point, glass transition temperature and acid value of the resulting mixture are preferably within the above-mentioned ranges.

[0067] The content of resin B is preferably 50% by mass or more, more preferably 70% by mass or more, even more preferably 90% by mass or more, and is 100% by mass or less, even more preferably 100% by mass, based on the total amount of the binder resin in the shell portion.

[0068] In the present invention, the mass ratio of the binder resin in the core portion to the binder resin in the shell portion (binder resin in the core portion / binder resin in the shell portion) is, from the viewpoint of achieving both improved low-temperature fixability and durability, 78 / 22 or more, preferably 80 / 20 or more, more preferably 82 / 18 or more, even more preferably 86 / 14 or more, even more preferably 88 / 12 or more, and is 95 / 5 or less, preferably 93 / 7 or less, more preferably 92 / 8 or less, and even more preferably 91 / 9 or less. In the present invention, the term "binder resin" refers to a resin component that functions as a binder resin for a toner, and does not include, for example, a polymer that coats titanium oxide, a resin component that functions as a dispersant for other components such as a release agent, or a resin component added as a charge control agent.

[0069] <Coloring agent> In the present invention, the colorant contains titanium oxide as a white pigment, and the colorant is titanium oxide coated with a polymer from the viewpoint of obtaining a toner excellent in low-temperature fixing property and durability. Here, "titanium oxide is coated with an addition polymer" refers to a state in which an addition polymer is adsorbed to titanium oxide. Although it is sufficient that at least a part of the surface of titanium oxide is coated with a polymer, it is preferable that the entire titanium oxide is coated with a polymer. Whether titanium oxide is coated with a polymer can be identified by analyzing a cut surface of the colorant. Specifically, it can be identified by analyzing the resin in contact with titanium oxide on the cut surface. The toner particles preferably contain a colorant in the core portion. From the viewpoint of obtaining a toner having excellent low-temperature fixing property and durability, it is preferable that the polymer coating titanium oxide as the colorant is an addition polymer E of raw material monomers including an addition polymerizable monomer having an anionic group and an addition polymerizable monomer having a polyalkylene oxide group.

[0070] (Titanium dioxide) The colorant contains titanium oxide, which is a white pigment. As the titanium oxide, rutile type titanium oxide or anatase type titanium oxide can be used, but from the viewpoints of stability and availability, rutile type titanium oxide is preferred. From the viewpoint of obtaining good dispersibility in the toner, titanium oxide is preferably surface-treated. The surface treatment of titanium oxide is not particularly limited, and may be either surface treatment with an organic substance or surface treatment with an inorganic substance. From the viewpoint of avoiding the influence of photocatalysis, titanium oxide surface-treated with an inorganic substance is preferable, titanium oxide surface-treated with at least one of silica and alumina is more preferable, and titanium oxide surface-treated with silica and alumina is even more preferable. By calcining the surface-treated titanium oxide powder at a temperature of 800° C. or higher and 1000° C. or lower, sintering between particles can be suppressed, and the fluidity and dispersibility of the titanium oxide can be improved. The particle shape of titanium oxide is not particularly limited and may be granular, needle-like, or the like.

[0071] The average primary particle size of titanium oxide is preferably 100 nm or more, more preferably 150 nm or more, and even more preferably 200 nm or more from the viewpoint of whiteness, and is preferably 500 nm or less, more preferably 400 nm or less, and even more preferably 300 nm or less, from the viewpoint of achieving both improved low-temperature fixability and durability. The average primary particle size of titanium oxide can be measured using a transmission electron microscope, specifically, 500 titanium oxide primary particles are extracted using image analysis using a transmission electron microscope, their particle sizes are measured, and the average is calculated to give the number average particle size. In addition, when titanium oxide has a major axis and a minor axis, the major axis is used for the calculation. Examples of commercially available titanium oxide for use in the present invention include trade names JR, JR-605, and JR-701 manufactured by Teika Corporation, and trade names Typeque CR-90 and CR-80 manufactured by Ishihara Sangyo Kaisha, Ltd.

[0072] The polymer that coats the titanium oxide, which is a white pigment, may be any polymer that can be used as a polymer dispersant for inorganic substances, and examples of such polymers include vinyl polymers, polyesters, and polyurethanes. A commercially available dispersion of polymer particles may also be used. Among these, a polymer having an anionic group and a nonionic group is preferred, as it has a good affinity with titanium oxide, captures titanium oxide inside the core-shell toner particles, and inhibits the white pigment from being detached from the toner particles. In particular, as a polymer that coats titanium oxide, which is a white pigment, from the viewpoints of excellent dispersibility of titanium oxide and achieving both improved low-temperature fixability and durability, an addition polymer of raw material monomers including an addition polymerizable monomer having an anionic group (hereinafter also referred to as an "anionic group-containing monomer") and an addition polymerizable monomer having a polyalkylene oxide group, which is a nonionic group (hereinafter also referred to as "addition polymer E").

[0073] (Addition polymer E) The addition polymer E is an addition polymer of raw material monomers including an addition polymerizable monomer having an anionic group (hereinafter also referred to as an "anionic group-containing monomer") and an addition polymerizable monomer having a polyalkylene oxide group. <Addition-polymerizable monomer having an anionic group> The addition polymer E has a constitutional unit derived from an addition polymerizable monomer having an anionic group (anionic group-containing monomer), whereby an anionic group is introduced.

[0074] From the viewpoints of achieving excellent dispersibility of titanium oxide and achieving both improved low-temperature fixability and durability, the anionic group-containing monomer preferably has an anionic group selected from the group consisting of a carboxy group, a sulfonic acid group, and a phosphate group. Examples of addition polymerizable monomers having a carboxy group (carboxy group-containing monomers) include acrylic acid, methacrylic acid, crotonic acid, itaconic acid, maleic acid, fumaric acid, citraconic acid, and 2-methacryloyloxyethylsuccinic acid. Examples of addition polymerizable monomers having a sulfonic acid group (sulfonic acid group-containing monomers) include styrenesulfonic acid, 2-acrylamido-2-methylpropanesulfonic acid, 3-sulfopropyl(meth)acrylate, and bis-(3-sulfopropyl)itaconic acid. Examples of addition polymerizable monomers having a phosphoric acid group (phosphate group-containing monomers) include vinylphosphonic acid, vinyl phosphate, bis(methacryloxyethyl)phosphate, diphenyl-2-acryloyloxyethyl phosphate, diphenyl-2-methacryloyloxyethyl phosphate, and dibutyl-2-acryloyloxyethyl phosphate.

[0075] As the anionic group-containing monomer, from the viewpoint of improving the dispersibility of titanium oxide in a dispersion liquid and in a toner, a carboxy group-containing monomer is preferably used, more preferably at least one selected from acrylic acid and methacrylic acid, and even more preferably methacrylic acid. The anionic group-containing monomer may form a salt, and examples of the salt include sodium salt and potassium salt.

[0076] From the viewpoints of achieving excellent dispersibility of titanium oxide and a balance between improved low-temperature fixability and durability, the content of the anionic group-containing monomer in the raw material monomers of the addition polymer E is preferably 5% by mass or more, more preferably 10% by mass or more, even more preferably 15% by mass or more, and is preferably 50% by mass or less, more preferably 35% by mass or less, even more preferably 20% by mass or less.

[0077] <Addition-polymerizable monomer having a polyalkylene oxide group> The raw material monomers for the addition polymer E used in the present invention contain, in addition to an anionic group-containing monomer, an addition polymerizable monomer having a polyalkylene oxide group (hereinafter, referred to as a polyalkylene oxide group-containing monomer). The polyalkylene oxide group-containing monomer is preferably a polyalkylene glycol (meth)acrylate, and the polyalkylene glycol (meth)acrylate is represented by the following formula (1).

[0078] [ka] (In formula (1), R 1 represents a hydrogen atom or a methyl group, R 2 represents a hydrogen atom or a monovalent hydrocarbon group having 1 to 20 carbon atoms, OA represents an oxyalkylene group having 2 to 4 carbon atoms, and n represents the average number of moles of alkylene oxide added, which is a number of 4 to 300.

[0079] R 1 represents a hydrogen atom or a methyl group, and is preferably a methyl group from the viewpoints of excellent dispersibility of titanium oxide and achieving both improved low-temperature fixability and durability. R 2 represents a hydrogen atom or a monovalent hydrocarbon group having from 1 to 20 carbon atoms, and is preferably a monovalent hydrocarbon group having from 1 to 20 carbon atoms. Examples of the hydrocarbon group include an alkyl group and an aryl group, and an alkyl group is preferable. The alkyl group preferably has 1 to 8 carbon atoms, more preferably has 1 to 3 carbon atoms, and further preferably is a methyl group. The aryl group is preferably one having 6 to 10 carbon atoms, more preferably a phenyl group or a naphthyl group, and even more preferably a phenyl group. OA represents an oxyalkylene group having from 2 to 4 carbon atoms, preferably an oxyethylene group or an oxypropylene group, more preferably an oxyethylene group. The average number of moles of oxyalkylene groups added, n, is 4 or more, preferably 8 or more, more preferably 12 or more, even more preferably 18 or more, and is preferably 300 or less, more preferably 150 or less, even more preferably 100 or less, even more preferably 30 or less.

[0080] The content of the polyalkylene oxide group-containing monomer in the raw material monomers of the addition polymer E is preferably 50% by mass or more, more preferably 65% ​​by mass or more, even more preferably 80% by mass or more, from the viewpoints of achieving excellent dispersibility of titanium oxide and a balance between improved low-temperature fixability and durability, and is preferably 95% by mass or less, more preferably 90% by mass or less, even more preferably 85% by mass or less.

[0081] The mass ratio of the anionic group-containing monomer to the polyalkylene oxide group-containing monomer (anionic group-containing monomer / alkylene oxide group-containing monomer) in the raw material monomers of the addition polymer E is, from the viewpoints of excellent dispersibility of titanium oxide and achieving both improved low-temperature fixability and durability, preferably 5 / 95 or more, more preferably 10 / 90 or more, even more preferably 15 / 85 or more, and is preferably 50 / 50 or less, more preferably 35 / 65 or less, even more preferably 20 / 80 or less.

[0082] <Hydrophobic monomer> In the present invention, the raw material monomers for the addition polymer may further contain a hydrophobic monomer in addition to the anionic group-containing monomer and the polyalkylene oxide group-containing monomer, as long as the effects of the present invention are not impaired. From the viewpoint of ease of production of the addition polymer E, examples of the hydrophobic monomer include alkyl (meth)acrylates and aromatic group-containing monomers. The alkyl (meth)acrylate is preferably a compound having an alkyl group having 1 to 22 carbon atoms, more preferably 6 to 18 carbon atoms, such as ethyl (meth)acrylate, (iso)propyl (meth)acrylate, (iso- or tertiary)butyl (meth)acrylate, and 2-ethylhexyl (meth)acrylate. Examples of aromatic group-containing monomers include styrene, α-methylstyrene, benzyl (meth)acrylate, and phenoxy (meth)acrylate. When the raw material monomer contains a hydrophobic monomer, the content of the hydrophobic monomer in the raw material monomer is preferably 0.1% by mass or more and preferably 5% by mass or less.

[0083] From the viewpoints of achieving excellent dispersibility of titanium oxide and a balance between improved low-temperature fixability and durability, the weight-average molecular weight of the addition polymer E is preferably 3,000 or more, more preferably 20,000 or more, even more preferably 40,000 or more, even more preferably 48,000 or more, and is preferably 200,000 or less, more preferably 80,000 or less, even more preferably 70,000 or less. The weight-average molecular weight can be measured by the method described in the Examples.

[0084] From the viewpoints of achieving excellent dispersibility of titanium oxide and a balance between improved low-temperature fixing ability and durability, the acid value of the addition polymer E is preferably 30 mgKOH / g or more, more preferably 80 mgKOH / g or more, even more preferably 100 mgKOH / g or more, and is preferably 500 mgKOH / g or less, more preferably 300 mgKOH / g or less, even more preferably 150 mgKOH / g or less. The acid value of the addition polymer E is measured by the method described in the Examples.

[0085] The addition polymer E can be produced, for example, by copolymerizing raw material monomers by a known polymerization method such as a solution polymerization method, a suspension polymerization method, an emulsion polymerization method, etc. Among these, the polymerization method is preferably a solution polymerization method in which raw material monomers are polymerized by heating in a solvent together with a polymerization initiator, a polymerization chain transfer agent, etc. The solvent used in the solution polymerization method is not particularly limited, but from the viewpoint of facilitating the preparation of the colorant dispersion liquid, it is preferable to use an aqueous medium. The aqueous medium means a medium mainly composed of water. In addition to water, an organic solvent may be added, and examples of the organic solvent other than water include aliphatic alcohols having 1 to 4 carbon atoms, ketones having 3 to 8 carbon atoms, ethers such as ethyl ether, propyl ether, and tetrahydrofuran, and esters such as methyl acetate and ethyl acetate. The content of water in the aqueous medium is preferably 60% by mass or more, more preferably 80% by mass or more, even more preferably 90% by mass or more, and even more preferably 100% by mass.

[0086] Examples of the polymerization initiator include peroxides such as dibutyl peroxide, persulfates such as ammonium persulfate and sodium persulfate, and azo compounds such as 2,2'-azobis(2,4-dimethylvaleronitrile). The amount of the polymerization initiator added is preferably 0.5 parts by mass or more and preferably 30 parts by mass or less based on 100 parts by mass of the raw material monomer. Examples of the polymerization chain transfer agent include mercaptans such as 2-mercaptoethanol and 3-mercaptopropionic acid. The amount of the polymerization chain transfer agent added is preferably 0.01 parts by mass or more and preferably 10 parts by mass or less based on 100 parts by mass of the raw material monomer. Preferred polymerization conditions vary depending on the type of polymerization initiator, raw material monomer, solvent, etc. used, but the polymerization temperature is preferably 30° C. or higher, more preferably 60° C. or higher, and preferably 95° C. or lower, more preferably 85° C. or lower. The polymerization time is preferably 1 hour or longer, more preferably 2 hours or longer, and preferably 20 hours or shorter, more preferably 10 hours or shorter. The polymerization atmosphere is preferably a nitrogen gas atmosphere, an inert gas atmosphere such as argon, etc.

[0087] In the colorant, the mass ratio of titanium oxide to the polymer (preferably addition polymer E) (titanium oxide / polymer) is, from the viewpoints of excellent dispersibility of titanium oxide and achieving both improved low-temperature fixability and durability, preferably 50 / 50 or more, more preferably 70 / 30 or more, even more preferably 85 / 15 or more, even more preferably 90 / 10 or more, even more preferably 95 / 5 or more, and is preferably 99.5 / 0.5 or less, more preferably 99.2 / 0.8 or less.

[0088] From the viewpoints of achieving excellent dispersibility of titanium oxide and achieving both improved low-temperature fixability and durability, the content of titanium oxide in the toner particles is preferably 10% by mass or more, more preferably 20% by mass or more, even more preferably 25% by mass or more, even more preferably 30% by mass or more, and is preferably 80% by mass or less, more preferably 60% by mass or less, even more preferably 50% by mass or less.

[0089] [Release Agent] The toner particles may preferably contain a release agent in the core portion. Examples of the release agent include hydrocarbon waxes such as polypropylene wax, polyethylene wax, polypropylene-polyethylene copolymer wax, microcrystalline wax, paraffin wax, and Fischer-Tropsch wax, or oxides thereof; ester waxes such as carnauba wax, montan wax, or deacidified waxes thereof, and fatty acid ester wax; fatty acid amides, fatty acids, higher alcohols, and fatty acid metal salts. These may be used alone or in combination of two or more. Of these, hydrocarbon waxes and ester waxes are preferred, and hydrocarbon waxes are more preferred. Among the hydrocarbon waxes, paraffin wax and Fischer-Tropsch wax are preferred.

[0090] The melting point of the release agent is preferably 60° C. or higher, more preferably 70° C. or higher, and is preferably 160° C. or lower, more preferably 140° C. or lower, and further preferably 120° C. or lower.

[0091] The amount of the release agent in the toner particles is preferably 0.1% by mass or more, more preferably 1% by mass or more, even more preferably 5% by mass or more, and preferably 30% by mass or less, more preferably 20% by mass or less, even more preferably 15% by mass or less.

[0092] <External additives> In the present invention, the toner for developing electrostatic images may be used as is in the form of toner particles, but it is preferable to use toner particles to which an external additive has been added. Examples of the external additive include inorganic fine particles such as hydrophobic silica, titanium oxide fine particles, alumina fine particles, cerium oxide fine particles, and carbon black, and polymer fine particles such as polycarbonate, polymethyl methacrylate, and silicone resin. Among these, hydrophobic silica is preferred. The external additives may be used alone or in combination of two or more kinds. Also, external additives of the same kind but different particle diameters may be used in combination. When the toner particles are surface-treated using an external additive, the amount of the external additive added is, relative to 100 parts by mass of the toner particles, preferably 1 part by mass or more, more preferably 2 parts by mass or more, even more preferably 3 parts by mass or more, and preferably 5 parts by mass or less, more preferably 4.5 parts by mass or less, even more preferably 4 parts by mass or less.

[0093] [Toner manufacturing method] The toner having the above-mentioned core-shell structure is preferably obtained by a method including the following steps 1 to 3. Step 1: A step of aggregating resin particles X, which contain an amorphous polyester resin A and preferably a crystalline polyester resin C in the same or different particles, in an aqueous medium to obtain core particles (aggregated particles 1); Step 2: A step of aggregating resin particles Y containing an amorphous polyester resin B to the core particles (aggregated particles 1) obtained in step 1 to obtain core-shell particles (aggregated particles 2); Step 3: A step of heating the aggregated particles 2 obtained in step 2 to fuse them and obtain fused particles. In step 1, resin particles X are aggregated in an aqueous medium to obtain core particles (aggregated particles 1). Here, it is preferable that the resin particles X contain an amorphous polyester resin A (resin A) and a crystalline polyester resin C (resin C). It is also preferable to aggregate a colorant and release agent particles in addition to the resin particles X, and it is more preferable to mix a resin particle dispersion containing the resin particles X, a colorant dispersion containing a colorant, and a release agent particle dispersion containing release agent particles to aggregate these particles. Each step will be described below.

[0094] [Process 1] Step 1 is a step of obtaining aggregated particles 1 by aggregating resin particles X, which contain resin A and preferably resin C in the same or different particles, in an aqueous medium. In step 1, the aggregated particles 1 are preferably obtained by aggregating a colorant together with the resin particles X. Furthermore, in step 1, it is preferable to aggregate release agent particles containing a release agent together with the resin particles X and the colorant. The resin particles X, the colorant, and the release agent particles used in step 1, and their production methods will be described in detail below.

[0095] <Resin particle X> The resin particle dispersion used in step 1 contains resin particles X. In order to obtain excellent low-temperature fixability and durability, the resin particles X preferably contain resin A and resin C in the same or different resin particles, and from the viewpoint of productivity, preferably contain resin A and resin C in the same resin particle.

[0096] (Preparation of Resin Particle Dispersion) The preparation of a resin particle dispersion containing resin particles X, preferably a resin particle dispersion containing resin A and resin C in the same or different resin particles, can be carried out using a known method, but is preferably carried out by a phase inversion emulsification method. An example of the phase inversion emulsification method is a method in which an aqueous medium is added to an organic solvent solution of a resin or a molten resin to carry out phase inversion emulsification.

[0097] The organic solvent used for phase inversion emulsification is not particularly limited as long as it dissolves the resin, but from the viewpoint of facilitating phase inversion, examples include alcohol-based solvents such as ethanol, isopropanol, isobutanol, etc.; ketone-based solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, diethyl ketone, etc.; ether-based solvents such as dibutyl ether, tetrahydrofuran, dioxane, etc.; and acetate-based solvents such as ethyl acetate, isopropyl acetate, etc. Among these, from the viewpoint of easy removal from the mixed solution after addition of the aqueous medium, ketone-based solvents and acetate-based solvents are preferred, and methyl ethyl ketone, ethyl acetate, and isopropyl acetate are more preferred. It is preferable to add a neutralizing agent to the organic solvent solution. Examples of the neutralizing agent include basic substances. Examples of the basic substance include alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, and nitrogen-containing basic substances such as ammonia, trimethylamine, and diethanolamine. The equivalent amount (mol %) of the neutralizing agent used relative to the acid groups of the resin contained in the resin particles X is, from the viewpoints of obtaining fine resin particles and improving dispersion stability, preferably 10 mol % or more, more preferably 30 mol % or more, even more preferably 40 mol % or more, and is preferably 90 mol % or less, more preferably 70 mol % or less. The equivalent amount (mol%) of the neutralizing agent used can be calculated by the following formula: When the equivalent amount of the neutralizing agent used is 100 mol% or less, it is synonymous with the degree of neutralization. Equivalent amount of neutralizing agent used (mol%) = [{weight of neutralizing agent added (g) / equivalent amount of neutralizing agent} / [{weighted average acid value of resin constituting resin particle X (mgKOH / g) × weight of resin constituting resin particle X (g)} / (56 × 1000)]] × 100

[0098] While stirring the organic solvent solution or the molten resin, the aqueous medium is gradually added to cause phase inversion. From the viewpoint of improving the dispersion stability of the resin particles X, the temperature of the organic solvent solution when the aqueous medium is added is preferably not less than the glass transition temperature of the resin constituting the resin particles X, more preferably not less than 50° C., even more preferably not less than 60° C., and is preferably not more than 85° C., more preferably not more than 80° C. The contents of resin A and resin C are as described above.

[0099] After the phase inversion emulsification, if necessary, the organic solvent may be removed from the obtained dispersion by distillation, etc. In this case, the amount of the remaining organic solvent in the dispersion is preferably 1% by mass or less, more preferably 0.5% by mass or less, and even more preferably substantially 0% by mass.

[0100] The volume median particle size (D 50 From the viewpoint of obtaining uniform aggregated particles having a desired particle size, the average particle diameter is preferably 0.05 μm or more, more preferably 0.08 μm or more, even more preferably 0.1 μm or more, and is preferably 0.8 μm or less, more preferably 0.4 μm or less, even more preferably 0.3 μm or less, and even more preferably 0.2 μm or less. From the viewpoint of obtaining uniform aggregated particles having a desired particle size, the CV value of the resin particles X in the dispersion is preferably 10% or more, more preferably 20% or more, and is preferably 40% or less, more preferably 35% or less. The volume median particle size of resin particle X (D 50 ) and the CV value is determined by the method described in the Examples below.

[0101] When resin particles Xa containing resin A and resin particles Xc containing resin C are used in combination, resin particles Xa and Xc can be obtained by the same method as described above. The amount of resin particles Xa and resin particles Xc added is preferably an amount that corresponds to the content of resin A and resin C described above.

[0102] (aqueous medium) In the present invention, the aqueous medium is a medium containing water as a main component, and the water content in the aqueous medium is preferably 70% by mass or more, more preferably 80% by mass or more, and even more preferably 90% by mass or more, and 100% by mass or less. As the water, deionized water, ion-exchanged water, or distilled water is preferable. Examples of components other than water that can form an aqueous medium together with water include organic solvents that dissolve in water, such as alkyl alcohols having 1 to 5 carbon atoms, dialkyl ketones having 3 to 5 carbon atoms, such as acetone and methyl ethyl ketone, and cyclic ethers, such as tetrahydrofuran. Among these, alkyl alcohols having 1 to 5 carbon atoms are preferred, and methanol or ethanol are more preferred.

[0103] <Coloring agent> The colorant is preferably mixed with the resin particles as a dispersion of the colorant, and then aggregated, so that the colorant is contained in the aggregated particles. The colorant can be obtained, for example, by mixing titanium oxide with a polymer. There is no particular limitation on the method for producing the colorant dispersion liquid. 50 However, it is preferable to mix titanium oxide with a dispersion of a polymer (preferably addition polymer E) using a bead mill or homogenizer. The following description will be given taking the case where addition polymer E is used as the polymer as an example, but the present invention is not limited thereto.

[0104] (Method of manufacturing colorant) The colorant can be obtained, for example, by mixing titanium oxide and the addition polymer E. There is no particular limitation on the method for producing the colorant dispersion liquid. 50 It is sufficient if the coloring agent can be controlled so as to obtain the coloring agent having the above properties, but it is preferable to mix titanium oxide and a dispersion of the addition polymer E using a bead mill or a homogenizer.

[0105] The method for producing the colorant dispersion preferably comprises the steps of: Step a: obtaining an aqueous dispersion of a neutralized addition polymer E; and Step b: A step of dispersing the dispersion obtained in step a with titanium oxide to obtain a dispersion of a colorant. It is a method having the following structure. Moreover, the step b is preferably a step of dispersing the dispersion liquid obtained in the step a and titanium oxide with a bead mill or a homogenizer.

[0106] The neutralizing agent may, for example, be a basic substance, such as an alkali metal hydroxide, such as sodium hydroxide, potassium hydroxide, or a nitrogen-containing basic substance, such as ammonia, trimethylamine, or diethanolamine. From the viewpoint of dispersion stability of the colorant, the degree of neutralization of the addition polymer E is preferably 10 mol% or more, more preferably 20 mol% or more, even more preferably 30 mol% or more, and is preferably 100 mol% or less, more preferably 80 mol% or less, even more preferably 60 mol% or less, even more preferably 50 mol% or less. The degree of neutralization of the addition polymer E can be calculated by the following formula. Degree of neutralization (mol%)=[{weight (g) of neutralizing agent added / equivalent weight of neutralizing agent} / {weight ratio of addition polymerizable monomer having an acidic group constituting addition polymer E×weight (g) of addition polymer E / molecular weight of addition polymerizable monomer having an acidic group}]×100 When the calculated degree of neutralization exceeds 100, the degree of neutralization is taken to be 100 mol %.

[0107] In the step b, the mass ratio of titanium oxide to addition polymer E [titanium oxide / addition polymer E] is as described above.

[0108] Examples of the apparatus used in step b include kneaders such as roll mills and kneaders, homogenizers such as Microfluidizer (manufactured by Microfluidic Corp.) and Starburst (manufactured by Sugino Machine Corp.), and media-type dispersers such as paint shakers and bead mills. Two or more of these apparatuses may be combined. Among these, from the viewpoint of reducing the particle size of titanium oxide, it is preferable to use a media-type disperser such as a bead mill or a homogenizer, and it is more preferable to use a media-type disperser. When using a media-type dispersing machine, the material of the media is preferably ceramics such as zirconia and titania, polymeric materials such as polyethylene and polyamide, metals, etc., and zirconia is preferable from the viewpoint of wear, etc. The shape of the media is not particularly limited, but is preferably bead-like (spherical). The dispersion time is preferably 0.3 hours or more, more preferably 1 hour or more, from the viewpoint of sufficiently finely pulverizing the colorant, and is preferably 100 hours or less, more preferably 50 hours or less, and even more preferably 20 hours or less, from the viewpoint of production efficiency of the colorant dispersion.

[0109] The colorant dispersion is preferably filtered through a wire mesh or the like to remove coarse particles, etc. When titanium oxide is dispersed using a bead mill, the removal of the bead mill and the removal of the coarse particles may be carried out simultaneously. In addition, various additives such as organic solvents, preservatives, and antifungal agents may be added to the dispersion of the colorant.

[0110] The content of titanium oxide in the colorant dispersion is preferably 5% by mass or more, more preferably 10% by mass or more, even more preferably 20% by mass or more, and preferably 50% by mass or less, more preferably 40% by mass or less, even more preferably 30% by mass or less. The solids concentration of the colorant dispersion is preferably 5% by mass or more, more preferably 10% by mass or more, even more preferably 20% by mass or more, and is preferably 70% by mass or less, more preferably 50% by mass or less, even more preferably 35% by mass or less.

[0111] Volume median particle size D of colorant 50 From the viewpoint of achieving both improved low-temperature fixability and durability, the thickness is preferably 0.1 μm or more, more preferably 0.15 μm or more, even more preferably 0.2 μm or more, and is preferably 0.5 μm or less, more preferably 0.4 μm or less, even more preferably 0.35 μm or less. From the viewpoint of achieving both improved low-temperature fixability and durability, the CV value of the colorant is preferably 10% or more, more preferably 20% or more, even more preferably 25% or more, and is preferably 45% or less, more preferably 40% or less, even more preferably 35% or less. Volume median particle size D of colorant 50 and CV values ​​are measured by the methods in the Examples.

[0112] <Release agent particles> The release agent is preferably incorporated into the core particles (aggregated particles 1) by mixing the release agent in a dispersion of release agent particles with a resin particle dispersion and a colorant dispersion and aggregating the mixture. The dispersion of release agent particles can be obtained using a surfactant, but is preferably obtained by mixing the release agent with resin particles P described below. By preparing the release agent particles using the release agent and resin particles P, the release agent particles are stabilized by the resin particles P, and it becomes possible to disperse the release agent in an aqueous medium without using a surfactant. It is considered that the dispersion of release agent particles has a structure in which a large number of resin particles P are attached to the surface of the release agent particles.

[0113] The resin constituting the resin particles P in which the release agent is dispersed is preferably a polyester resin, and it is more preferable to use a composite resin D having a polyester resin segment and an addition polymerization resin segment.

[0114] The softening point of the composite resin D is preferably 70° C. or higher, more preferably 85° C. or higher, and is preferably 140° C. or lower, more preferably 100° C. or lower. The acid value of the composite resin D is preferably 5 mgKOH / g or more, more preferably 20 mgKOH / g or more, and is preferably 40 mgKOH / g or less, more preferably 30 mgKOH / g or less, from the viewpoint of obtaining fine resin particles and from the viewpoint of obtaining a fine release agent particle dispersion.

[0115] The suitable ranges of other resin properties of the composite resin D and suitable examples of the raw material monomers constituting the resin are the same as those shown for the amorphous polyester resin A. The dispersion of the resin particles P can be obtained, for example, by the above-mentioned phase inversion emulsification method. The volume median particle size of resin particles P (D 50 From the viewpoint of dispersion stability of the release agent particles, the average particle diameter is preferably 0.01 μm or more, more preferably 0.03 μm or more, and is preferably 0.3 μm or less, more preferably 0.2 μm or less. From the viewpoint of dispersion stability of the release agent particles, the CV value of the resin particles P is preferably 10% or more, more preferably 15% or more, and is preferably 40% or less, more preferably 30% or less. The volume median particle size of resin particles P (D 50 ) and CV value are measured by the method described in the Examples.

[0116] The release agent particle dispersion liquid can be obtained, for example, by dispersing a dispersion liquid of the release agent and the resin particles P, and optionally an aqueous medium, at a temperature equal to or higher than the melting point of the release agent, using a dispersing machine such as a homogenizer, a high-pressure dispersing machine, or an ultrasonic dispersing machine. The heating temperature during dispersion is preferably equal to or higher than the melting point of the release agent and 80°C or higher, and is preferably equal to or lower than a temperature 10°C higher than the softening point of the resin contained in the resin particles P and 100°C or lower.

[0117] The amount of the resin particles P is preferably 5 parts by mass or more, more preferably 30 parts by mass or more, and preferably 100 parts by mass or less, more preferably 50 parts by mass or less, based on 100 parts by mass of the release agent.

[0118] Volume median particle size of release agent particles (D 50From the viewpoint of obtaining uniform aggregated particles by aggregation, the average particle size is preferably 0.05 μm or more, more preferably 0.2 μm or more, even more preferably 0.4 μm or more, and is preferably 1 μm or less, more preferably 0.8 μm or less, even more preferably 0.6 μm or less. The CV value of the release agent particles is preferably 10% or more, more preferably 20% or more, and is preferably 40% or less, more preferably 30% or less. Volume median particle size of release agent particles (D 50 ) and CV value are measured by the method described in the Examples.

[0119] Aggregated particles 1 may also contain additives such as charge control agents, magnetic powders, flowability improvers, conductivity adjusters, reinforcing fillers such as fibrous substances, antioxidants, antiaging agents, and cleaning improvers.

[0120] <Mixing conditions> In step 1, it is preferable to mix the resin particles X and the colorant in an aqueous medium, and aggregate the resin particles X and the colorant to obtain aggregated particles. The mixing of the resin particles X and the colorant is preferably carried out by mixing a resin particle dispersion containing the resin particles X with a colorant dispersion containing the colorant. It is also preferable that the resin particle dispersion is an aqueous dispersion of resin particles, and the colorant dispersion is an aqueous dispersion of the colorant. In step 1, it is preferable to aggregate the release agent particles together with the resin particles X and the colorant.

[0121] (Surfactant) The mixed dispersion may be prepared in the presence of a surfactant in order to improve the dispersion stability of optional components such as the resin particles X, the colorant, and the release agent particles added as necessary. Examples of the surfactant include anionic surfactants such as alkylbenzene sulfonates and alkyl ether sulfates; and nonionic surfactants such as polyoxyethylene alkyl ethers and polyoxyethylene alkenyl ethers. When a surfactant is used, the amount of the surfactant used, as the total amount of the surfactant, is preferably 0.1 part by mass or more, more preferably 0.5 part by mass or more, and preferably 10 parts by mass or less, more preferably 5 parts by mass or less, per 100 parts by mass of the resin particles X.

[0122] The dispersion of the resin particles X, the colorant, and the optional components are mixed by a conventional method. From the viewpoint of efficiently performing aggregation, it is preferable to add an aggregating agent to the mixed dispersion obtained by the mixing.

[0123] (Flocculant) Examples of the flocculant include organic flocculants such as cationic surfactants of quaternary salts and polyethyleneimine; inorganic metal salts such as sodium sulfate, sodium nitrate, sodium chloride, calcium chloride, and calcium nitrate; inorganic ammonium salts such as ammonium sulfate, ammonium chloride, and ammonium nitrate; and inorganic flocculants such as divalent or higher metal complexes. From the viewpoint of improving the flocculation property and obtaining uniform flocculated particles, inorganic flocculants having a valence of 1 to 5 are preferred, inorganic metal salts having a valence of 1 to 2 and inorganic ammonium salts having a valence of 1 to 2 are more preferred, and ammonium sulfate is even more preferred. The flocculant may be added as it is, but is preferably dissolved in an aqueous medium and added as an aqueous solution. When the flocculant is added as an aqueous solution, the pH of the aqueous flocculant solution may be adjusted.

[0124] For example, a flocculant is added to a mixed dispersion containing resin particles X, a colorant, and optionally release agent particles at 0° C. or higher and 40° C. or lower, in an amount of preferably 5 parts by mass or higher and 60 parts by mass or lower relative to 100 parts by mass of resin particles X, and the resin particles X and the colorant are aggregated in an aqueous medium to obtain aggregated particles 1. Furthermore, from the viewpoint of promoting aggregation, it is preferable to increase the temperature of the dispersion after adding the flocculant.

[0125] The volume median particle size D of the aggregated particles 1 obtained in step 1 50 is preferably 3 μm or more, more preferably 4 μm or more, even more preferably 5 μm or more, and is preferably 10 μm or less, more preferably 8 μm or less, even more preferably 6.5 μm or less. It is preferred that the agglomeration process be continued until the desired volume median particle size is reached.

[0126] [Process 2] Step 2 is a step of aggregating resin particles Y containing an amorphous polyester-based resin B with the aggregated particles 1 obtained in step 1 to obtain aggregated particles 2. In step 2, it is preferable to add a dispersion of resin particles Y to the dispersion of aggregated particles 1 described above to further attach resin particles Y to aggregated particles 1, thereby obtaining a dispersion of aggregated particles 2.

[0127] <Resin particles Y> The resin particle dispersion used in step 2 contains resin particles Y. The resin particles Y contain resin B in order to obtain excellent low-temperature fixability and durability. (Preparation of Resin Particle Dispersion) The resin particles Y are preferably produced by a method in which a resin component containing the resin B and, if necessary, an optional component such as a surfactant are dispersed in an aqueous medium to obtain a resin particle Y dispersion. The method for obtaining the resin particle Y dispersion can be exemplified by the same methods as those for the resin particle dispersion of resin X. Preferred embodiments of the aqueous medium and organic solvent that can be used, the mass ratio of resin B to the organic solvent, the degree of neutralization of resin B, the amount of aqueous medium to be added, the mixing temperature, and other preferred ranges are the same as those for the production of resin particle X.

[0128] The solid content concentration of the obtained dispersion of resin particles Y is preferably 7% by mass or more, more preferably 10% by mass or more, even more preferably 15% by mass or more, and is preferably 50% by mass or less, more preferably 35% by mass or less, even more preferably 25% by mass or less, from the viewpoint of improving the productivity of the toner and the dispersion stability of the resin particles Y. The solid content is the total amount of non-volatile components such as the resin, surfactant, etc.

[0129] The volume median particle size (D 50From the viewpoint of obtaining a core-shell toner that achieves both improved low-temperature fixability and durability, the particle size is preferably 0.04 μm or more, more preferably 0.06 μm or more, and is preferably 0.5 μm or less, more preferably 0.2 μm or less.

[0130] In addition, from the viewpoint of improving the productivity of the resin particle Y dispersion, the coefficient of variation (CV value) (%) of the particle size distribution of the resin particles Y is preferably 5% or more, more preferably 15% or more, and is preferably 50% or less, more preferably 30% or less. Volume median particle size of resin particle Y (D 50 ) and the coefficient of variation (CV value) are measured by the method described in the Examples.

[0131] Before adding the dispersion of resin particles Y to the dispersion of aggregated particles 1, an aqueous medium may be added to the dispersion of aggregated particles 1 to dilute it. When the dispersion of resin particles Y is added to the dispersion of aggregated particles 1, the aggregating agent may be used in this step to efficiently attach the resin particles Y to the aggregated particles 1. The temperature when the resin particle Y dispersion is added is preferably 40° C. or higher and preferably 80° C. or lower, from the viewpoint of obtaining a toner excellent in low-temperature fixing property and durability.

[0132] The resin particle Y dispersion may be added continuously over a certain period of time, may be added all at once, or may be added in several divided portions, but from the viewpoint of promoting selective adhesion and improving the productivity of the toner, it is preferable to add it continuously over a certain period of time. The time for continuous addition depends on the scale of production, but from the viewpoint of obtaining uniform aggregated particles 2 and improving the productivity of the toner, it is preferably 1 hour or more, and preferably 10 hours or less, more preferably 3 hours or less.

[0133] From the viewpoint of obtaining a toner having excellent low-temperature fixing property and durability, the amount of resin particles Y added is an amount such that the mass ratio of resin particles Y to resin particles X (resin particles Y / resin particles X) is preferably 0.05 or more, more preferably 0.07 or more, even more preferably 0.08 or more, and is preferably 0.9 or less, more preferably 0.5 or less, even more preferably 0.3 or less, even more preferably 0.2 or less.

[0134] The volume median particle size (D 50 From the viewpoint of obtaining a core-shell toner that achieves both improved low-temperature fixability and durability, the particle size is preferably 2 μm or more, more preferably 3 μm or more, even more preferably 4 μm or more, and is preferably 10 μm or less, more preferably 8 μm or less, even more preferably 6.5 μm or less.

[0135] [Step 3] Step 3 is a step of increasing the temperature of the aggregated particles 2 obtained in step 2 to fuse them together, thereby obtaining fused particles. In step 3, the particles in the aggregated particles that were primarily physically attached to each other are fused together to form toner particles having a core-shell structure. In this step, the temperature is maintained at or above the glass transition temperature of resin B from the viewpoint of improving the fusion property of the aggregated particles and from the viewpoint of achieving both improved low-temperature fixability and durability of the toner. From the viewpoint of improving the fusion properties of the aggregated particles and improving the productivity of the toner, the holding temperature in the fusion step is preferably at least 2° C. higher than the glass transition temperature of resin A, more preferably at least 3° C. higher, and even more preferably at least 5° C. higher, and is preferably not higher than 30° C. higher, more preferably not higher than 25° C. higher, and even more preferably not higher than 20° C. higher than the glass transition temperature of resin A. In this case, the time for which the resin A is maintained at a temperature equal to or higher than the glass transition temperature is preferably 1 minute or more, more preferably 10 minutes or more, even more preferably 30 minutes or more, and is preferably 240 minutes or less, more preferably 120 minutes or less, even more preferably 90 minutes or less, from the viewpoint of obtaining a toner having excellent low-temperature fixing property and durability. It is preferable to maintain the temperature at the above temperature until the desired circularity is achieved.

[0136] The volume median particle size (D 50 From the viewpoint of achieving both low-temperature fixability and durability of the toner, the particle size is preferably 2 μm or more, more preferably 4 μm or more, even more preferably 5 μm or more, and is preferably 10 μm or less, more preferably 8 μm or less, even more preferably 7 μm or less. The volume median particle diameter of the core-shell particles obtained in step 3 is preferably equal to or smaller than the volume median particle diameter of the aggregated particles 2. That is, in step 3, it is preferable that aggregation and fusion of the aggregated particles 2 do not occur.

[0137] [Post-processing process] In the present invention, a post-treatment step may be carried out after step 3, and it is preferable to obtain toner particles by isolation. Since the core-shell particles obtained in step 3 are present in an aqueous medium, it is preferable to first carry out solid-liquid separation. For solid-liquid separation, a suction filtration method or the like is preferably used. It is preferable to wash after the solid-liquid separation. At this time, it is preferable to remove the added surfactant, etc., so that, in the case where the surfactant has a cloud point, washing with an aqueous medium at a temperature below the cloud point of the surfactant is preferable. It is preferable to wash multiple times.

[0138] Next, drying is preferably performed. The temperature during drying is preferably set so that the temperature of the core-shell particles themselves is lower than the glass transition temperature of resin B, and more preferably 10° C. or more lower. As the drying method, a vacuum low-temperature drying method, a vibration-type fluidized drying method, a spray drying method, a freeze drying method, a flash jet method, or the like is preferably used.

[0139] [Toner Particles] The toner particles obtained by drying or the like can be used as they are as a toner for developing electrostatic images, but it is preferable to use the toner particles after surface treatment as described later as a toner for developing electrostatic images. The volume median particle size of toner particles (D 50 From the viewpoint of improving the productivity of the toner and obtaining a toner excellent in low-temperature fixing property and durability, the particle size is preferably 2 μm or more, more preferably 4 μm or more, even more preferably 5 μm or more, and is preferably 10 μm or less, more preferably 8 μm or less, even more preferably 7 μm or less. The CV value of the toner particles is preferably 12% or more, more preferably 14% or more, and even more preferably 16% or more, from the viewpoint of improving the productivity of the toner, and is preferably 32% or less, more preferably 30% or less, and even more preferably 27% or less, from the viewpoint of obtaining high-quality images. From the viewpoint of obtaining a toner having excellent low-temperature fixing property and durability, the circularity of the toner particles is preferably 0.955 or more, more preferably 0.960 or more, even more preferably 0.965 or more, and is preferably 0.990 or less, more preferably 0.985 or less, even more preferably 0.980 or less.

[0140] <External additives> The toner particles can be used as they are as a toner for developing electrostatic images, but it is preferable to use the toner particles after adding a fluidizing agent or the like as an external additive to the surface of the toner particles.

[0141] <Toner for developing electrostatic images> The toner for developing electrostatic images obtained as described above can be used as a one-component developer, or mixed with a carrier to form a two-component developer. EXAMPLES

[0142] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. Each property value was measured and evaluated by the following methods. In the expression "alkylene oxide (X)", the number X in parentheses means the average number of moles of alkylene oxide added.

[0143] [Measurement method] [Polyester (based) resin, hydrocarbon wax acid value, hydroxyl value] Measurements were performed in accordance with JIS K0070:1992, except that the measurement solvent was chloroform.

[0144] [Resin softening point, maximum endothermic peak temperature, crystallinity index, glass transition temperature, melting point] (1) Softening point Using a flow tester "CFT-500D" (Shimadzu Corporation), 1 g of sample was heated at a temperature increase rate of 6°C / min, while applying a load of 1.96 MPa with the plunger, and extruding the sample from a nozzle with a diameter of 1 mm and a length of 1 mm. The plunger descent amount of the flow tester was plotted against the temperature, and the temperature at which half of the sample flowed out was taken as the softening point. (2) Crystallinity index Using a differential scanning calorimeter "Q100" (manufactured by TA Instruments Japan Co., Ltd.), 0.02 g of sample was weighed into an aluminum pan and cooled to 0°C at a rate of 10°C / min. The sample was then left to stand for 1 minute, after which it was heated to 180°C at a rate of 10°C / min and the calorific value was measured. The temperature of the peak with the largest peak area among the observed endothermic peaks was taken as the endothermic maximum peak temperature (1), and the crystallinity index was calculated by (softening point (°C)) / (endothermic maximum peak temperature (1) (°C)). (3) Melting point and glass transition temperature Using a differential scanning calorimeter "Q100" (manufactured by TA Instruments Japan Co., Ltd.), 0.02 g of the sample was weighed into an aluminum pan, heated to 200°C, and cooled from that temperature to 0°C at a rate of 10°C / min. The sample was then heated at a rate of 10°C / min, and the calorific value was measured. Among the endothermic peaks observed, the temperature of the peak with the largest peak area was taken as the maximum endothermic peak temperature (2). In the case of a crystalline resin, this peak temperature was taken as the melting point. In the case of an amorphous resin, when a peak was observed, the temperature of the peak was taken as the glass transition temperature. When no peak was observed but a step was observed, the temperature at the intersection of the tangent showing the maximum slope of the curve at the step and an extension of the baseline on the low temperature side of the step was taken as the glass transition temperature.

[0145] [Weight average molecular weight of addition polymer E] Using a solution of 0.2 M phosphate buffer / acetonitrile = 9 / 1 (volume ratio) as an eluent, the measurement was performed by gel permeation chromatography (GPC apparatus (HLC-8320GPC) manufactured by Tosoh Corporation, columns (PW+G4000PW+G2500PW) manufactured by Tosoh Corporation, flow rate: 1.0 mL / min, temperature: 40°C) using polyethylene glycol, the weight average molecular weight of which had been previously determined to be monodisperse, as a standard substance.

[0146] [Acid value of addition polymer E] The measurement was performed according to the potentiometric titration method of JIS K 0070.

[0147] [Solids Concentration of Aqueous Addition Polymer Solution and Colorant Dispersion] 10.0 g of sodium sulfate, which had been kept constant in a desiccator, was weighed out into a 30 mL polypropylene container (φ=40 mm, height=30 mm), and about 1.0 g of the sample was added thereto and mixed, then accurately weighed, and maintained at 105°C for 2 hours to remove volatile matter, and further left in the desiccator for 15 minutes, and the mass was measured. The mass of the sample after removing the volatile matter was taken as the solid content, and divided by the mass of the sample added to obtain the solid content concentration (%).

[0148] [Melting point of release agent] Using a differential scanning calorimeter "Q100" (manufactured by TA Instruments Japan Co., Ltd.), 0.02 g of the sample was weighed into an aluminum pan, heated to 200°C, and cooled to 0°C at a rate of 10°C / min. The sample was then heated at a rate of 10°C / min, the calorific value was measured, and the maximum endothermic peak temperature was taken as the melting point.

[0149] [Volume median particle size D of resin particles, release agent particles, and colorant50 and CV value] (1) Measuring device: Laser diffraction type particle size measuring device "LA-920" (manufactured by Horiba Ltd.) (2) Measurement conditions: Distilled water was added to the measurement cell, and the volume median particle size D50 and volume average particle size were measured at a concentration that brought the absorbance into the appropriate range. The CV value (coefficient of variation (particle size distribution)) was calculated according to the following formula. CV value (%) = (Standard deviation of particle size distribution / Volume average particle size) x 100

[0150] [Solid Content Concentration of Resin Particle Dispersion and Release Agent Particle Dispersion] Using an infrared moisture meter "FD-230" (Kett Electric Laboratory Co., Ltd.), the moisture content (mass%) of 5 g of the measurement sample was measured at a drying temperature of 150°C and measurement mode 96 (monitoring time 2.5 min / fluctuation range 0.05%). The solid content concentration was calculated according to the following formula. Solid concentration (mass%) = 100-moisture (mass%)

[0151] [Volume median particle diameter of agglomerated particles D 50 and CV value] Volume median particle size of agglomerated particles D 50 was measured as follows: Measuring instrument: "Coulter Multisizer (registered trademark) III" (manufactured by Beckman Coulter, Inc.) Aperture diameter: 50μm Analysis software: "Multisizer (registered trademark) III version 3.51" (Beckman Coulter, Inc.) Electrolyte: "Isoton (registered trademark) II" (manufactured by Beckman Coulter, Inc.) Measurement conditions: The sample dispersion is added to 100 mL of the electrolyte to adjust the concentration so that the particle size of 30,000 particles can be measured in 20 seconds. Then, 30,000 particles are measured and the volume median particle size D is calculated from the particle size distribution. 50 The volume average particle size was calculated. The CV value (coefficient of variation (particle size distribution)) was calculated according to the following formula. CV value (%) = (Standard deviation of particle size distribution / Volume average particle size) x 100

[0152] [Circularity of fused particles] The circularity of the fused particles was measured under the following conditions. Measurement equipment: Flow-type particle image analyzer "FPIA-3000" (Sysmex Corporation) Preparation of dispersion: A dispersion of fused particles was prepared by diluting with deionized water to a solids concentration of 0.001 to 0.05% by mass. Measurement mode: HPF measurement mode

[0153] [Volume median particle size of toner particles D 50 and CV value] Volume median particle size of toner particles D 50 was measured as follows: The measuring instrument, aperture diameter, analysis software, and electrolyte are the volume median particle diameter D 50 The same as above was used. Dispersion liquid: Polyoxyethylene lauryl ether "EMULGEN (registered trademark) 109P" (manufactured by Kao Corporation, HLB: 13.6) was dissolved in the electrolyte to obtain a dispersion liquid with a concentration of 5% by mass. Dispersion conditions: 10 mg of a toner measurement sample was added to 5 mL of the dispersion liquid, and dispersed for 1 minute using an ultrasonic disperser. Thereafter, 25 mL of electrolyte was added, and the mixture was further dispersed for 1 minute using an ultrasonic disperser to prepare a sample dispersion liquid. Measurement conditions: The sample dispersion is added to 100 mL of the electrolyte to adjust the concentration so that the particle size of 30,000 particles can be measured in 20 seconds. Then, 30,000 particles are measured and the volume median particle size D is calculated from the particle size distribution. 50 and the volume average particle size were determined. The CV value (%) was calculated according to the following formula. CV value (%) = (Standard deviation of particle size distribution / Volume average particle size) x 100

[0154] [Evaluation method] [Low Temperature Fixability of Toner] A colorless transparent PP label "KEP 70CA P2041 8KA" (manufactured by Lintec Corporation, thickness 70 μm) was printed with a commercially available printer "COREFIDO C712dnw" (manufactured by OKI Data Corporation) at a toner adhesion of 0.45 mg / cm 2The solid image was output without being fixed. Next, the same printer was prepared with a modified temperature-variable fixing unit, the temperature of the fixing unit was set to 90° C., and the toner was fixed on an A4 sheet in portrait orientation at a speed of 1.7 seconds per sheet to obtain a printout. In the same manner, the temperature of the fixing unit was increased by 5° C. each time, and the toner was fixed to obtain a printed matter. A piece of mending tape, Scotch (registered trademark) Mending Tape 810 (manufactured by Sumitomo 3M Limited, width 18 mm), was cut to a length of 50 mm and lightly applied to the top margin of the printed image from the top to the solid image. Then, a 500 g cylindrical weight (contact area: 1,963 mm 2 ) was placed on the print and pressed against it once at a speed of 10 mm / s. The applied tape was then peeled off from the bottom end at a peeling angle of 90° and a speed of 10 mm / s to obtain a print after the tape had been peeled off. 30 sheets of high-quality paper "Colored High-Quality Paper Blue Thick" (manufactured by Hokuetsu Corporation) were placed under the print before and after the tape had been applied, and the reflected image density of the fixed image portion of each print before and after the tape had been peeled off was measured using a colorimeter "SpectroEye" (manufactured by GretagMacbeth, light irradiation conditions: standard light source D50, observation field of view 2°, density standard DINNB, absolute white standard), and the fixing rate was calculated from each reflected image density according to the following formula. Fixation rate (%) = (reflection image density after tape peeling / reflection image density before tape application) x 100 The lowest temperature at which the fixing rate was 95% or more was determined as the minimum fixing temperature.

[0155] [Durability] The toner was loaded into the ID cartridge of a commercially available printer, "Microline (registered trademark) 5400" (manufactured by Oki Data Corporation), which was equipped with an ID cartridge modified so that the developing roller could be visually observed, and the printer was run at 70 rpm (equivalent to 36 sheets / min) at 25°C and 50% relative humidity. The occurrence of streaks on the surface of the developing roller was visually observed, and the time until streaks occurred was measured and used as an index of durability. The higher the value, the better the durability. Incidentally, streaky unevenness refers to a condition in which the amount of toner adhering to the developing roller varies due to blade filming or the like, causing streaks on the developing roller. The occurrence of streaky unevenness results in uneven shading, blurring, streaks, etc. in the image when printed.

[0156] [Manufacturing method] [Production of amorphous polyester resin] Production Example A1 (Production of Resin A-1) The inside of a 10 L four-neck flask equipped with a nitrogen inlet tube, a dehydration tube, a stirrer, and a thermocouple was replaced with nitrogen, and 4,054 g of a propylene oxide (2.2) adduct of bisphenol A, 1,058 g of terephthalic acid, 30 g of tin(II) di(2-ethylhexanoate), 3.0 g of 3,4,5-trihydroxybenzoic acid (gallic acid), and 514 g of hydrocarbon wax "Parakol 6490" (manufactured by Nippon Seiro Co., Ltd., acid value 18 mg KOH / g, hydroxyl value 97 mg KOH / g) were placed in the flask. The mixture was heated to 235°C with stirring under a nitrogen atmosphere and maintained at 235°C for 8 hours, and then the pressure in the flask was reduced and maintained at 8 kPa for 1 hour. After that, the pressure was returned to atmospheric pressure, and then the mixture was cooled to 160°C. While the mixture was kept at 160°C, a mixture of 2,937g of styrene, 734g of stearyl methacrylate, 133g of acrylic acid, and 441g of dibutyl peroxide was added dropwise over 3 hours. After that, the mixture was kept at 160°C for 30 minutes, and then heated to 200°C. The pressure in the flask was further reduced and kept at 8kPa for 1 hour. After that, the mixture was returned to atmospheric pressure, and then cooled to 190°C. 215g of fumaric acid, 351g of sebacic acid, 222g of trimellitic anhydride, and 3.0g of 4-tert-butylcatechol were added, and the temperature was raised to 210°C at 10°C / hr. Then, the mixture was reacted at 4kPa until the desired softening point was obtained, and resin A-1 was obtained. The physical properties are shown in Table 1.

[0157] Manufacturing Example B1 (Manufacturing of Resin B-1) The inside of a four-neck flask equipped with a nitrogen inlet tube, a dehydration tube, a stirrer, and a thermocouple was replaced with nitrogen, and 3,264g of ethylene oxide (2.2) adduct of bisphenol A, 1,334g of terephthalic acid, 25g of tin (II) di(2-ethylhexanoate), and 2.5g of 3,4,5-trihydroxybenzoic acid (gallic acid) were added, and the temperature was raised to 235°C while stirring under a nitrogen atmosphere, and after maintaining at 235°C for 6 hours, the pressure in the flask was further reduced and maintained at 8.3kPa for 1 hour. After that, the pressure was returned to atmospheric pressure, and the flask was cooled to 180°C, and 135g of adipic acid, 75g of dodecenylsuccinic anhydride, and 193g of trimellitic anhydride were added, and the temperature was raised to 220°C at 10°C / hr, and then the pressure in the flask was reduced and the reaction was carried out at 10kPa until the desired softening point, to obtain resin B-1. The physical properties are shown in Table 1.

[0158] Production Examples B2 to B4 (Production of Resins B-2 to B-4) Resins B-2 to B-4 were obtained in the same manner as in Production Example B1, except that the raw material compositions were changed as shown in Table 1. The physical properties are shown in Table 1.

[0159] Manufacturing Example D1 (Manufacturing of Resin D-1) The inside of a 10L four-neck flask equipped with a nitrogen inlet tube, a dehydration tube, a stirrer, and a thermocouple was replaced with nitrogen, and 4,313g of a propylene oxide (2.2) adduct of bisphenol A, 818g of terephthalic acid, 727g of succinic acid, 30g of tin (II) di(2-ethylhexanoate), and 3.0g of 3,4,5-trihydroxybenzoic acid (gallic acid) were added, and the temperature was raised to 235°C while stirring under a nitrogen atmosphere, and the flask was kept at 235°C for 5 hours, after which the pressure in the flask was reduced and kept at 8kPa for 1 hour. After that, the pressure was returned to atmospheric pressure, and the flask was cooled to 160°C, and a mixture of 2,756g of styrene, 689g of stearyl methacrylate, 142g of acrylic acid, and 413g of dibutyl peroxide was added dropwise over 1 hour while the temperature was kept at 160°C. After that, the temperature was kept at 160° C. for 30 minutes, and then the temperature was raised to 200° C., and the pressure inside the flask was further reduced, and the reaction was carried out at 8 kPa until the desired softening point was reached, thereby obtaining Resin D-1. The physical properties are shown in Table 1.

[0160] [Table 1]

[0161] [Production of crystalline polyester resin] Manufacturing Example C1 (Manufacturing of Resin C-1) The inside of a 10L four-neck flask equipped with a nitrogen inlet tube, a dehydration tube, a stirrer, and a thermocouple was replaced with nitrogen, 3,416g of 1,10-decanediol and 4,084g of sebacic acid were added, and the temperature was raised to 135°C while stirring, and after maintaining at 135°C for 3 hours, the temperature was raised from 135°C to 200°C over 10 hours. Then, 23g of tin(II) di(2-ethylhexanoate) was added, and the mixture was maintained at 200°C for another hour, after which the pressure in the flask was reduced and the mixture was maintained under a reduced pressure of 8.3kPa for 1 hour to obtain resin C-1. The physical properties are shown in Table 2.

[0162] [Table 2]

[0163] [Production of resin particle dispersion] Production Example X1 (Production of Resin Particle Dispersion X-1) 210 g of Resin A-1, 90 g of Resin C-1, and 360 g of methyl ethyl ketone were placed in a 3 L vessel equipped with a stirrer, a reflux condenser, a dropping funnel, a thermometer, and a nitrogen inlet tube, and the resins were dissolved over 2 hours at 73° C. A 5% by mass aqueous solution of sodium hydroxide was added to the resulting solution so that the degree of neutralization was 50 mol% relative to the acid value of the resin, and the mixture was stirred for 30 minutes. Next, while maintaining the temperature at 73°C, 600 g of deionized water was added over 60 minutes while stirring at 280 r / min (circumferential speed 88 m / min) to cause phase inversion emulsification. While continuing to maintain the temperature at 73°C, methyl ethyl ketone was distilled off under reduced pressure to obtain an aqueous dispersion. Thereafter, while continuing to stir at 280 r / min (circumferential speed 88 m / min), the aqueous dispersion was cooled to 30°C, and deionized water was added so that the solid concentration was 20 mass%, to obtain resin particle dispersion X-1. The volume median particle diameter D of the obtained resin particles was 50 and CV values ​​are shown in Table 3.

[0164] Production Example Y1 (Production of Resin Particle Dispersion Y-1) 300 g of Resin B-1 and 300 g of methyl ethyl ketone were placed in a 3 L vessel equipped with a stirrer, a reflux condenser, a dropping funnel, a thermometer, and a nitrogen inlet tube, and the resin was dissolved over 2 hours at 40° C. A 5% by mass aqueous solution of sodium hydroxide was added to the resulting solution so that the degree of neutralization with respect to the acid value of the resin was 60 mol%, and the mixture was stirred for 30 minutes. Next, while maintaining the temperature at 40°C, 600g of deionized water was added over 60 minutes while stirring at 280r / min (circumferential speed 88m / min) to cause phase inversion emulsification. The temperature was raised to 73°C, and methyl ethyl ketone was distilled off under reduced pressure to obtain an aqueous dispersion. Thereafter, the aqueous dispersion was cooled to 30°C while stirring at 280r / min (circumferential speed 88m / min), and deionized water was added so that the solid concentration was 20 mass%, to obtain resin particle dispersion Y-1. The volume median particle diameter D of the obtained resin particles was 50 and CV values ​​are shown in Table 3.

[0165] Production Examples Y2 to Y4 (Production of Resin Particle Dispersions Y-2 to Y-4) Resin particle dispersions Y-2 to Y-4 were obtained in the same manner as in Production Example Y1, except that the resins used were changed as shown in Table 3. The volume median particle diameter D 50 and CV values ​​are shown in Table 3.

[0166] Production Example P1 (Production of Resin Particle Dispersion P-1) 200g of resin D-1 and 200g of methyl ethyl ketone were placed in a 3L container equipped with a stirrer, reflux condenser, dropping funnel, thermometer and nitrogen inlet tube, and the resin was dissolved at 73°C for 2 hours. A 5% by mass aqueous solution of sodium hydroxide was added to the obtained solution so that the degree of neutralization was 60mol% with respect to the acid value of resin D-1, and the solution was stirred for 30 minutes. Next, while maintaining the temperature at 73°C, 700g of deionized water was added over 50 minutes while stirring at 280r / min (circumferential speed 88m / min), and phase inversion emulsification was performed. While continuing to maintain the temperature at 73°C, methyl ethyl ketone was distilled off under reduced pressure to obtain an aqueous dispersion liquid. Thereafter, the aqueous dispersion liquid was cooled to 30°C while stirring at 280r / min (circumferential speed 88m / min), and deionized water was added so that the solid content concentration was 20% by mass, thereby obtaining a resin particle dispersion liquid P-1. The volume median particle diameter D of the obtained resin particles was 50 and CV values ​​are shown in Table 3.

[0167] [Table 3]

[0168] [Production of release agent particle dispersion] Production Example W1 (Production of Release Agent Particle Dispersion W-1) Into a 1 L beaker were added 120 g of deionized water, 86 g of resin particle dispersion P-1, and 40 g of paraffin wax "HNP-9" (manufactured by Nippon Seiro Co., Ltd., melting point 75°C), and the mixture was melted by maintaining the temperature at 90 to 95°C and stirred to obtain a molten mixture. The obtained molten mixture was dispersed for 20 minutes using an ultrasonic homogenizer "US-600T" (manufactured by Nippon Seiki Seisakusho Co., Ltd.) while maintaining the temperature at 90 to 95°C, and then cooled to room temperature (20°C). Deionized water was added to adjust the solid content to 20% by mass, and a release agent particle dispersion W-1 was obtained. The volume median particle diameter D of the release agent particles in the dispersion was 50 The diameter was 0.47 μm and the CV value was 27%.

[0169] Production Example W2 (Production of Release Agent Particle Dispersion W-2) A release agent particle dispersion W-2 was obtained in the same manner as in Production Example W1, except that the type of release agent used was changed to Fischer-Tropsch wax "FNP-0090" (manufactured by Nippon Seiro Co., Ltd., melting point 90°C). 50 The diameter was 0.45 μm and the CV value was 28%.

[0170] [Production of Addition Polymer E] Production Example E1 (Production of Addition Polymer E-1) 233g of water was charged into a 2L glass reaction vessel equipped with a dropping funnel, and the temperature was raised to 80°C under a nitrogen atmosphere. Next, under a nitrogen gas atmosphere, a monomer solution of 166g of methoxypolyethylene glycol monomethacrylate (average number of moles of ethylene oxide (EO) added n = 23, manufactured by Shin-Nakamura Chemical Co., Ltd., product name "NK Ester M-230G") and 34g of methacrylic acid as a dropping solution 1, 27g of a 7% concentration 2-mercaptoethanol aqueous solution as a dropping solution 2, and 32g of a 6% concentration ammonium persulfate aqueous solution as a dropping solution 3 were each gradually dropped into the reaction vessel over 90 minutes at the same time. Next, 11g of a 6% concentration ammonium persulfate aqueous solution was gradually dropped into the reaction vessel over 30 minutes, and after the drop was completed, the mixture was aged at 80°C for 1 hour. Thereafter, the mixture was cooled to 40°C, neutralized by adding 13g of a 48% concentration sodium hydroxide aqueous solution, and water was added so that the solid content concentration became 40%, to obtain an aqueous solution of addition polymer E-1.

[0171] Production Examples E2 and E3 (Production of Addition Polymers E-2 and E-3) Aqueous solutions of addition polymers E-2 and E-3 were obtained in the same manner as in Production Example E1, except that the monomers and amounts thereof shown in Table 4 were changed. The details of the monomers in Table 4 are as follows. MPEGMA (n=23): Methoxypolyethyleneglycol methacrylate (average number of EO moles added = 23, manufactured by Shin-Nakamura Chemical Co., Ltd., product name "NK Ester M-230G") MPEGMA (n=9): Methoxypolyethyleneglycol methacrylate (average number of EO moles added = 9, manufactured by Shin-Nakamura Chemical Co., Ltd., product name "NK Ester M-90G") MPEGMA (n=120): methoxypolyethylene glycol methacrylate (average number of moles of EO added=120, used was that produced in Production Example I below.) Manufacturing example I (Production of methoxypolyethylene glycol methacrylate (n=120)) Using polyethylene glycol monomethyl ether (weight average molecular weight 5,300) having an average EO addition mole number of 120 melted at 80°C, the target product, methoxypolyethylene glycol methacrylate (average EO addition mole number = 120), was obtained by the method described in Example 1 of JP-A-11-228636.

[0172] [Table 4]

[0173] (Production of Colorant Dispersion) Production Example Z1 (Production of Colorant Dispersion Z-1) In a 250 mL polyethylene bottle, 0.765 g (effective content 0.306 g) of the aqueous solution of the addition polymer E-1 obtained in Production Example E1 (solid content concentration 40%), 15 g of titanium oxide (CR-80 manufactured by Ishihara Sangyo Kaisha, Ltd., rutile type, alumina, silica treatment, average particle size 0.25 μm), 15.3 g of water were added, and 369 g of zirconia beads (diameter 2 mm) were added, and dispersion was performed for 8 hours at 25 ° C. using a benchtop pot mill stand (manufactured by AS ONE Corporation). The zirconia beads were removed using a mesh, and the solid content concentration was adjusted with water to obtain colorant dispersion liquid Z-1 (solid content concentration 30 mass %).

[0174] Production Examples Z2 and Z3 (Production of Colorant Dispersions Z-2 and Z-3) Colorant dispersions Z-2 and Z-3 (solid concentration 30% by mass) were obtained in the same manner as in Production Example Z1, except that the addition polymer E-1 in Production Example Z1 was changed to the addition polymer shown in Table 5.

[0175] Production Examples Z4 and Z5 (Production of Colorant Dispersions Z-4 and Z-5) Colorant dispersions Z-4 and Z-5 (solid concentration 30% by mass) were obtained in the same manner as in Production Example Z1, except that the mass ratio of the colorant and the addition polymer shown in Table 5 was changed in Production Example Z1.

[0176] Production Example Z6 (Production of Colorant Dispersion Z-6) Into a 250 mL polyethylene bottle, 2.04 g (active content 0.31 g) of 15 mass% sodium dodecylbenzenesulfonate aqueous solution "Neopelex G-15" (Kao Corporation, anionic surfactant, LAS), 15 g of titanium oxide, 15.3 g of water were added, and 369 g of zirconia beads were added, and dispersion was carried out for 8 hours at 25°C using a benchtop pot mill stand (AS ONE Corporation). The zirconia beads were removed using a mesh, and the solid concentration was adjusted with water to obtain titanium oxide dispersion Z-6 (solid concentration 30 mass%).

[0177] Production Example Z7 (Production of Colorant Dispersion Z-7) In a 250 mL polyethylene bottle, 0.31 g of polyoxyethylene distyrenated phenyl ether "EMULGEN A-60" (Kao Corporation, nonionic surfactant), 15 g of titanium oxide (Ishihara Sangyo Kaisha, Ltd. CR-93, rutile type, Al, Si treatment, average particle size 0.28 μm), 15.3 g of water were added, and 369 g of zirconia beads were added, and dispersion was performed for 8 hours at 25 ° C. using a benchtop pot mill stand (AS ONE Corporation). The zirconia beads were removed using a mesh, and the solid concentration was adjusted with water to obtain titanium oxide dispersion liquid Z-7 (solid concentration 30 mass %).

[0178] [Table 5]

[0179] Example 1 (Preparation of Toner 1) In a 3 L four-neck flask equipped with a dehydration tube, a stirrer, and a thermocouple, 400 g of resin particle dispersion X-1, 36 g of release agent particle dispersion W-1, 36 g of release agent particle dispersion W-2, 177 g of colorant dispersion Z-1, 8 g of a 10 mass% aqueous solution of polyoxyethylene (50) lauryl ether "EMULGEN 150" (manufactured by Kao Corporation, nonionic surfactant), and 5 g of a 15 mass% aqueous solution of sodium dodecylbenzenesulfonate "NEOPELEX G-15" (manufactured by Kao Corporation, anionic surfactant) were mixed at a temperature of 25° C. Next, an aqueous solution obtained by dissolving 37 g of ammonium sulfate in 550 g of deionized water and adding 43 g of a 4.8 mass% aqueous solution of potassium hydroxide was added dropwise at 25° C. over 10 minutes while stirring the mixture, and then the temperature was raised to 62° C. over 2 hours to obtain the volume median particle diameter D of the aggregated particles. 50 The temperature was maintained at 62° C. until the particle size reached 5.6 μm, thereby obtaining a dispersion of aggregated particles 1. The aggregated particle 1 dispersion was cooled to 57° C., and while maintaining the temperature at 57° C., 48 g of resin particle dispersion Y-2 was added over 90 minutes to obtain aggregated particle 2 dispersion in which resin particles were aggregated to aggregated particles 1. To the obtained dispersion liquid of aggregated particles 2, 226 g of sodium polyoxyethylene lauryl ether sulfate "EMAL E-27C" (manufactured by Kao Corporation, anionic surfactant, effective concentration 27% by mass) and 1,358 g of deionized water were added. Thereafter, the temperature was raised to 75°C over one hour, and the temperature was maintained at 75°C until the circularity reached 0.970, thereby obtaining a dispersion liquid of fused particles in which the aggregated particles were fused. The obtained dispersion of fused particles was cooled to 30° C., and the solid matter was separated by suction filtration, washed with deionized water at 25° C., and then vacuum dried at 30° C. for 48 hours to obtain toner particles. The physical properties of the obtained toner particles are shown in Table 6. 100 parts by mass of the toner particles, 2.5 parts by mass of hydrophobic silica "RY50" (manufactured by Nippon Aerosil Co., Ltd., number average particle size: 0.04 μm), and 1.0 part by mass of hydrophobic silica "Cabosil (registered trademark) TS720" (manufactured by Cabot Japan Co., Ltd., number average particle size: 0.012 μm) were placed in a Henschel mixer, stirred, and passed through a 150 mesh sieve to obtain toner 1. The obtained toner was evaluated, and the results are shown in Table 6.

[0180] Examples 2 to 7, Comparative Examples 1, 4, and 5 (Production of toners 2-7, 13, 16, and 17) A toner was prepared in the same manner as in Example 1, except that the types of resin particle dispersion liquid and colorant dispersion liquid used were changed as shown in Table 6. The physical properties of the obtained toner particles and the evaluation results of the toner are shown in Table 6. In Example 6, the amount of colorant dispersion used was changed to 175 g, and in Example 7, the amount of colorant dispersion used was changed to 191 g.

[0181] Example 8 (Preparation of Toner 8) In the same manner as in Example 1, a dispersion of aggregated particles 1 was obtained. The aggregated particle 1 dispersion was cooled to 57° C., and while maintaining the temperature at 57° C., 36 g of resin particle dispersion Y-3 was added over 90 minutes to obtain aggregated particle 2 dispersion in which resin particles were aggregated to aggregated particles 1. To the obtained dispersion liquid of aggregated particles 2, 223 g of sodium polyoxyethylene lauryl ether sulfate "EMAL E-27C" (manufactured by Kao Corporation, anionic surfactant, effective concentration 27% by mass) and 1,337 g of deionized water were added. Thereafter, the temperature was raised to 75°C over one hour, and the temperature was maintained at 75°C until the circularity reached 0.970, thereby obtaining a dispersion liquid of fused particles in which the aggregated particles were fused. The obtained dispersion of fused particles was cooled to 30° C., and the solid matter was separated by suction filtration, washed with deionized water at 25° C., and then vacuum dried at 30° C. for 48 hours to obtain toner particles. The physical properties of the obtained toner particles are shown in Table 6. Toner particles were added external additives in the same manner as in Example 1 to obtain toner 8. The toner thus obtained was evaluated, and the results are shown in Table 6.

[0182] Example 9 (Preparation of Toner 9) In the same manner as in Example 1, a dispersion of aggregated particles 1 was obtained. The aggregated particle 1 dispersion was cooled to 57° C., and while maintaining the temperature at 57° C., 60 g of resin particle dispersion Y-3 was added over 90 minutes to obtain aggregated particle 2 dispersion in which resin particles were aggregated to aggregated particles 1. To the obtained dispersion liquid of aggregated particles 2, 230 g of sodium polyoxyethylene lauryl ether sulfate "EMAL E-27C" (manufactured by Kao Corporation, anionic surfactant, effective concentration 27% by mass) and 1,380 g of deionized water were added. Thereafter, the temperature was raised to 75°C over one hour, and the temperature was maintained at 75°C until the circularity reached 0.970, thereby obtaining a dispersion liquid of fused particles in which the aggregated particles were fused. The obtained dispersion of fused particles was cooled to 30° C., and the solid matter was separated by suction filtration, washed with deionized water at 25° C., and then vacuum dried at 30° C. for 48 hours to obtain toner particles. The physical properties of the obtained toner particles are shown in Table 6. Toner particles were added external additives in the same manner as in Example 1 to obtain toner 9. The toner thus obtained was evaluated.

[0183] Example 10 (Preparation of Toner 10) In the same manner as in Example 1, a dispersion of aggregated particles 1 was obtained. The aggregated particle 1 dispersion was cooled to 57° C., and while maintaining the temperature at 57° C., 24 g of resin particle dispersion Y-2 was added over 90 minutes to obtain aggregated particle 2 dispersion in which resin particles were aggregated to aggregated particles 1. To the obtained dispersion liquid of aggregated particles 2, 219 g of sodium polyoxyethylene lauryl ether sulfate "EMAL E-27C" (manufactured by Kao Corporation, anionic surfactant, effective concentration 27% by mass) and 1,316 g of deionized water were added. Thereafter, the temperature was raised to 75°C over one hour, and the temperature was maintained at 75°C until the circularity reached 0.970, thereby obtaining a dispersion liquid of fused particles in which the aggregated particles were fused. The obtained dispersion of fused particles was cooled to 30° C., and the solid matter was separated by suction filtration, washed with deionized water at 25° C., and then vacuum dried at 30° C. for 48 hours to obtain toner particles. The physical properties of the obtained toner particles are shown in Table 6. Toner particles were added external additives in the same manner as in Example 1 to obtain toner 10. The toner thus obtained was evaluated, and the results are shown in Table 6.

[0184] Example 11 (Preparation of Toner 11) In the same manner as in Example 1, a dispersion of aggregated particles 1 was obtained. The aggregated particle 1 dispersion was cooled to 57° C., and while maintaining the temperature at 57° C., 80 g of resin particle dispersion Y-2 was added over 90 minutes to obtain aggregated particle 2 dispersion in which resin particles were aggregated to aggregated particles 1. To the obtained dispersion liquid of aggregated particles 2, 236 g of sodium polyoxyethylene lauryl ether sulfate "EMAL E-27C" (manufactured by Kao Corporation, anionic surfactant, effective concentration 27% by mass) and 1,415 g of deionized water were added. Thereafter, the temperature was raised to 75°C over one hour, and the temperature was maintained at 75°C until the circularity reached 0.970, thereby obtaining a dispersion liquid of fused particles in which the aggregated particles were fused. The obtained dispersion of fused particles was cooled to 30° C., and the solid matter was separated by suction filtration, washed with deionized water at 25° C., and then vacuum dried at 30° C. for 48 hours to obtain toner particles. The physical properties of the obtained toner particles are shown in Table 6. To the toner particles, external additives were added in the same manner as in Example 1 to obtain toner 11. The toner thus obtained was evaluated, and the results are shown in Table 6.

[0185] Example 12 (Preparation of Toner 12) In the same manner as in Example 1, a dispersion of aggregated particles 1 was obtained. The aggregated particle 1 dispersion was cooled to 57° C., and while maintaining the temperature at 57° C., 100 g of resin particle dispersion Y-4 was added over 90 minutes to obtain aggregated particle 2 dispersion in which resin particles were aggregated to aggregated particles 1. To the obtained dispersion liquid of aggregated particles 2, 242 g of sodium polyoxyethylene lauryl ether sulfate "EMAL E-27C" (manufactured by Kao Corporation, anionic surfactant, effective concentration 27% by mass) and 1,451 g of deionized water were added. Thereafter, the temperature was raised to 75°C over one hour, and the temperature was maintained at 75°C until the circularity reached 0.970, thereby obtaining a dispersion liquid of fused particles in which the aggregated particles were fused. The obtained dispersion of fused particles was cooled to 30° C., and the solid matter was separated by suction filtration, washed with deionized water at 25° C., and then vacuum dried at 30° C. for 48 hours to obtain toner particles. The physical properties of the obtained toner particles are shown in Table 6. Toner 12 was obtained by adding external additives to the toner particles in the same manner as in Example 1. The toner thus obtained was evaluated. The results are shown in Table 6.

[0186] Comparative Example 2 (Preparation of Toner 14) In the same manner as in Example 1, a dispersion of aggregated particles 1 was obtained. The aggregated particle 1 dispersion was cooled to 57° C., and while maintaining the temperature at 57° C., 16 g of resin particle dispersion Y-2 was added over 90 minutes to obtain aggregated particle 2 dispersion in which resin particles were aggregated to aggregated particles 1. To the obtained dispersion liquid of aggregated particles 2, 217 g of sodium polyoxyethylene lauryl ether sulfate "EMAL E-27C" (manufactured by Kao Corporation, anionic surfactant, effective concentration 27% by mass) and 1,301 g of deionized water were added. Thereafter, the temperature was raised to 75°C over one hour, and the temperature was maintained at 75°C until the circularity reached 0.970, thereby obtaining a dispersion liquid of fused particles in which the aggregated particles were fused. The obtained dispersion of fused particles was cooled to 30° C., and the solid matter was separated by suction filtration, washed with deionized water at 25° C., and then vacuum dried at 30° C. for 48 hours to obtain toner particles. The physical properties of the obtained toner particles are shown in Table 6. Toner particles were added external additives in the same manner as in Example 1 to obtain toner 14. The toner thus obtained was evaluated, and the results are shown in Table 6.

[0187] Comparative Example 3 (Preparation of Toner 15) In the same manner as in Example 1, a dispersion of aggregated particles 1 was obtained. The aggregated particle 1 dispersion was cooled to 57° C., and while maintaining the temperature at 57° C., 120 g of resin particle dispersion Y-2 was added over 90 minutes to obtain aggregated particle 2 dispersion in which resin particles were aggregated to aggregated particles 1. To the obtained dispersion liquid of aggregated particles 2, 248 g of sodium polyoxyethylene lauryl ether sulfate "EMAL E-27C" (manufactured by Kao Corporation, anionic surfactant, effective concentration 27% by mass) and 1,486 g of deionized water were added. Thereafter, the temperature was raised to 75°C over one hour, and the temperature was maintained at 75°C until the circularity reached 0.970, thereby obtaining a dispersion liquid of fused particles in which the aggregated particles were fused. The obtained dispersion of fused particles was cooled to 30° C., and the solid matter was separated by suction filtration, washed with deionized water at 25° C., and then vacuum dried at 30° C. for 48 hours to obtain toner particles. The physical properties of the obtained toner particles are shown in Table 6. Toner particles were added external additives in the same manner as in Example 1 to obtain toner 15. The toner thus obtained was evaluated, and the results are shown in Table 6.

[0188] [Table 6]

[0189] From the results of the Examples and Comparative Examples described above, it is apparent that the present invention provides a toner having excellent low-temperature fixing properties and durability.

Claims

1. A white toner for developing an electrostatic image, the white toner comprising toner particles containing a colorant containing a white pigment and a binder resin, The toner particles have a core-shell structure, the core portion contains an amorphous polyester resin A including a polycondensate of an alcohol component and a carboxylic acid component, and contains 60 mol % or more of a propylene oxide adduct of bisphenol A relative to 100 mol % of the total alcohol components of the amorphous polyester resin A; the shell portion contains an amorphous polyester resin B containing a polycondensate of an alcohol component and a carboxylic acid component, and the amorphous polyester resin B contains 10 mol % or more of a propylene oxide adduct of bisphenol A relative to 100 mol % of the total alcohol components; a mass ratio of the binder resin of the core portion to the binder resin of the shell portion (binder resin of the core portion / binder resin of the shell portion) is 78 / 22 or more and 95 / 5 or less; the colorant is titanium dioxide coated with a polymer, the polymer is an addition polymer of raw material monomers including an addition polymerizable monomer having an anionic group and an addition polymerizable monomer having a polyalkylene oxide group; White toner for developing electrostatic images.

2. 2. The white toner for developing electrostatic images according to claim 1, wherein a mass ratio of titanium oxide to the polymer in the colorant (titanium oxide / polymer) is 50 / 50 or more and 99.5 / 0.5 or less.

3. 3. The white toner for developing electrostatic images according to claim 1, wherein the core part further contains a crystalline polyester resin C.

4. The white toner for developing electrostatic images according to any one of claims 1 to 3, wherein the amorphous polyester resin A is an amorphous composite resin A including a polyester resin segment which is a polycondensate of an alcohol component and a carboxylic acid component, and an addition polymerization resin segment which is an addition polymerization product of a raw material monomer including a styrene compound.

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