Toner for electrostatic charge image development

Abstract

To provide a toner for electrostatic charge image development with which a print image superior in bending resistance and document offset resistance can be obtained.SOLUTION: The present invention relates to a toner for electrostatic charge image development that includes toner particles containing amorphous resin A, crystalline polyester resin C and polyurethane resin U, wherein the crystalline polyester resin C is a polycondensation product of an alcohol component and a carboxylic acid component, and meets at least one of conditions 1 and 2 and has an ester group concentration of 6.0 to 10.5 m mol / g. Here, the alcohol component contains 80 mol% or larger of ethylene glycol (condition 1), and the calboxylic acid component contains 80 mol% or larger of α,ω-aliphatic dicarboxylic acid with a carbon number of 4 (condition 2).SELECTED DRAWING: None

Description

[Technical Field]

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

[0002] In the field of electrophotography, with the development of electrophotographic systems, there is a demand for the development of electrophotographic toners that can accommodate higher image quality and higher speeds. Furthermore, in recent years, there has been an increasing demand for electrophotographic printing in the field of commercial printing, such as for catalogs and pamphlets, and from the viewpoint of the robustness of printed matter, there is a demand for the development of toners that are excellent in bending resistance.

[0003] Patent Document 1 discloses a toner containing a binder resin including a non-crystalline polyester resin (A), a crystalline polyester resin (B), and a polyurethane-type thermoplastic elastomer (C), with the aim of providing a toner or the like that maintains low-temperature fixability while exhibiting excellent bending resistance and scratch resistance. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2013-160801 Summary of the Invention [Problem to be solved by the invention]

[0005] Printed matter obtained by forming a printed image on a printing medium such as paper or plastic film using a toner containing a flexible and elastic polyurethane resin has excellent bending resistance, but when multiple printed matter are stored stacked together, they tend to be prone to document offset, in which color transfer occurs from the printed image to the opposing printing medium. Therefore, the present invention relates to a toner for developing electrostatic images that can produce printed matter that is excellent in bending resistance and document offset resistance. [Means for solving the problem]

[0006] The present inventors have discovered that by forming a printed image on a printing medium such as paper or plastic film using an electrostatic charge developing toner containing an amorphous resin, a crystalline polyester resin, and a polyurethane resin, wherein the crystalline polyester resin is a polycondensate of an alcohol component and a carboxylic acid component, the alcohol component contains a specific amount or more of ethylene glycol and / or the carboxylic acid component contains a specific amount or more of an α,ω-aliphatic dicarboxylic acid having four carbon atoms, and the ester group concentration of the crystalline polyester resin is within a specific range, it is possible to obtain a printed matter that is excellent in bending resistance and document offset resistance. The present invention relates to the following [1]. [1] A toner for developing electrostatic images, comprising toner particles containing an amorphous resin A, a crystalline polyester resin C, and a polyurethane resin U, A toner for developing electrostatic images, wherein the crystalline polyester resin C is a polycondensate of an alcohol component and a carboxylic acid component, satisfies at least one of the following conditions 1 and 2, and has an ester group concentration of 6.0 mmol / g or more and 10.5 mmol / g or less: (Condition 1) The alcohol component contains 80 mol% or more of ethylene glycol (Condition 2) The carboxylic acid component contains 80 mol% or more of α,ω-aliphatic dicarboxylic acids having 4 carbon atoms. [Effects of the Invention]

[0007] According to the present invention, there is provided a toner for developing electrostatic images that can produce printed matter that is excellent in bending resistance and document offset resistance. DETAILED DESCRIPTION OF THE INVENTION

[0008] [Electrostatic image developing toner] The toner for developing electrostatic images (hereinafter also simply referred to as "toner") of the present invention comprises toner particles containing an amorphous resin A, a crystalline polyester resin C, and a polyurethane resin U, wherein the crystalline polyester resin C is a polycondensate of an alcohol component and a carboxylic acid component, the alcohol component contains 80 mol % or more of ethylene glycol and / or the carboxylic acid component contains 80 mol % or more of an α,ω-aliphatic dicarboxylic acid having 4 carbon atoms, and the ester group concentration of the crystalline polyester resin C is 6.0 mmol / g or more and 10.5 mmol / g or less. It should be noted that toner particles containing amorphous resin A, crystalline polyester resin C, and polyurethane resin U (hereinafter simply referred to as "toner particles") can be used as they are as the toner of the present invention, but it is preferable to use the toner after adding a fluidizing agent or the like as an external additive to the surface of the toner particles.

[0009] The reason why the toner of the present invention can provide printed matter having excellent folding resistance and document offset resistance is not clear, but is thought to be as follows.

[0010] The reason for the decline in document offset resistance of printed materials obtained by forming a printed image on a printing medium using a toner containing polyurethane resin is thought to be that the polyurethane resin is exposed to the surface of the printing coating (printed image) during printing, and the cohesive properties derived from the urethane bonds in the polyurethane resin are exerted as adhesive properties, making it easier for the printed image to stick to the opposing printing medium when the printed materials are stored stacked on top of each other. In the present invention, amorphous resin A is combined with crystalline polyester resin C, which, relative to polyurethane resin U, contains 80 mol % or more of ethylene glycol as an alcohol component and / or 80 mol % or more of a C4 α,ω-aliphatic dicarboxylic acid as a carboxylic acid component, such as fumaric acid or succinic acid, and has an ester group concentration of 6.0 mmol / g to 10.5 mmol / g. In crystalline polyester resin C, strong hydrogen bonds form between adjacent ester groups derived from ethylene glycol or a C4 α,ω-aliphatic dicarboxylic acid and the urethane bonds present in polyurethane resin U. Furthermore, by setting the ester group concentration to 6.0 mmol / g to 10.5 mmol / g, the affinity between crystalline polyester resin C and amorphous resin A can be maintained. This improves the dispersibility of polyurethane resin U in toner. As a result, it is presumed that exposure of polyurethane resin U to the surface of the printed coating is suppressed, and the elasticity and cohesiveness of polyurethane resin U in the toner are significantly exhibited, resulting in printed matter that is excellent in both bending resistance and document offset resistance. The reason why the present invention is effective is only a presumption, and is not limited to the above description.

[0011] The definitions of various terms used in this specification are shown below. In the specification, the carboxylic acid component of the polyester resin includes not only the compound itself but also anhydrides that decompose during the reaction to produce carboxylic acids, and alkyl esters of each carboxylic acid (alkyl groups having 1 to 3 carbon atoms). Whether a resin is crystalline or amorphous is determined by its crystallinity index. The crystallinity index is defined as the ratio of the softening point of the resin to the endothermic maximum peak temperature (softening point (°C) / endothermic maximum peak temperature (°C)) measured by the 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 an endothermic peak is observed, one with a crystallinity index of less than 0.6 or more than 1.4. The crystallinity index can be adjusted appropriately by adjusting 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 parenthetical expressions "(iso or tertiary)" and "(iso)" refer to both the presence and absence of these prefixes; the absence of these prefixes indicates normal. "(Meth)acrylic acid" means at least one selected from acrylic acid and methacrylic acid. The term "styrenic compound" means unsubstituted or substituted styrene.

[0012] [Toner particles] The toner particles contain an amorphous resin A, a crystalline polyester resin C, and a polyurethane resin U. The toner particles may contain each of the components, such as the amorphous resin A, the crystalline polyester resin C, and the polyurethane resin U, either alone or in combination of two or more. Furthermore, the raw materials for each component contained in the toner particles, such as the alcohol component and the carboxylic acid component, may be used either alone or in combination of two or more.

[0013] <Amorphous resin A> In the present invention, the amorphous resin A preferably contains at least one selected from an amorphous polyester resin A and a styrene-acrylic resin. Hereinafter, the amorphous polyester resin A may be referred to as "resin A."

[0014] (Amorphous polyester resin A) Resin A contains a polyester resin segment that is a polycondensation product of an alcohol component and a carboxylic acid component. Examples of resin A include polyester resins and composite resins containing polyester resin segments and addition polymerization resin segments.

[0015] Examples of the alcohol component of Resin A include alkylene oxide adducts of aromatic diols, aliphatic diols, alicyclic diols, and trihydric or higher polyhydric alcohols. Among these, alkylene oxide adducts of aromatic diols are preferred.

[0016] 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):

[0017] [ka] (In the formula, OR 1 and R 2 O is an oxyalkylene group, and R 1 and R 2 are each independently an ethylene group or a propylene group, x and y are each a positive number that indicates the average number of moles of alkylene oxide added, 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.

[0018] Examples of the alkylene oxide adduct of bisphenol A represented by formula (I) include a propylene oxide adduct of bisphenol A and an ethylene oxide adduct of bisphenol A. In the alcohol component, the content of alkylene oxide adduct of bisphenol A is preferably 60 mol % or more, more preferably 80 mol % or more, even more preferably 90 mol % or more, and is 100 mol % or less, even more preferably 100 mol %.

[0019] Examples of 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 (neopentyl glycol), 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,12-dodecanediol, and 3-methyl-1,5-pentanediol.

[0020] 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 added moles: 2 to 12).

[0021] Examples of trihydric or higher polyhydric alcohols include glycerin, pentaerythritol, trimethylolpropane, and sorbitol.

[0022] Examples of the carboxylic acid component of Resin A include dicarboxylic acids and trivalent or higher polycarboxylic acids.

[0023] Examples of dicarboxylic acids include aromatic dicarboxylic acids, aliphatic dicarboxylic acids, and alicyclic dicarboxylic acids. Among these, at least one selected from aromatic dicarboxylic acids and aliphatic dicarboxylic acids is preferred.

[0024] 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 30 mol% or more, more preferably 40 mol% or more, even more preferably 50 mol% or more, and is 100 mol% or less, preferably 95 mol% or less, more preferably 90 mol% or less, even more preferably 85 mol% or less.

[0025] The aliphatic dicarboxylic acid preferably has 2 or more carbon atoms, more preferably 3 or more carbon atoms, and preferably has 30 or less carbon atoms, more preferably 20 or less carbon atoms. Examples of 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 acids substituted with an aliphatic hydrocarbon group having from 1 to 20 carbon atoms. Examples of succinic acids substituted with an aliphatic hydrocarbon group having from 1 to 20 carbon atoms include dodecylsuccinic acid, dodecenylsuccinic acid, and octenylsuccinic acid. Of these, fumaric acid, sebacic acid, and succinic acids substituted with an aliphatic hydrocarbon group having from 1 to 20 carbon atoms are preferred. The amount of aliphatic dicarboxylic acid in the carboxylic acid component is preferably 1 mol% or more, more preferably 4 mol% or more, even more preferably 7 mol% or more, and preferably 50 mol% or less, more preferably 45 mol% or less, even more preferably 40 mol% or less.

[0026] An example of the alicyclic dicarboxylic acid is cyclohexanedicarboxylic acid.

[0027] The trivalent or higher polyvalent carboxylic acid is preferably a trivalent carboxylic acid, such as trimellitic acid. The amount of trivalent or higher polycarboxylic acid in the carboxylic acid component is preferably 1 mol% or more, more preferably 4 mol% or more, even more preferably 7 mol% or more, and is preferably 25 mol% or less, more preferably 20 mol% or less, even more preferably 15 mol% or less.

[0028] 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.

[0029] When the resin A is a composite resin, an example of the addition polymerized resin segment is an addition polymer of raw material monomers containing a styrene-based compound. Examples of styrene compounds include unsubstituted or substituted styrene. Examples of the substituent substituted 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 sulfonic acid group, or a salt thereof. Examples of styrene 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 styrene-based compounds 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 75% 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.

[0030] 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; halovinyl compounds such as vinyl chloride; vinyl esters such as vinyl acetate and vinyl propionate; vinyl ethers such as methyl vinyl 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. 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 alkyl (meth)acrylates 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. Of these, 2-ethylhexyl (meth)acrylate or stearyl (meth)acrylate is preferred, stearyl (meth)acrylate is more preferred, and stearyl methacrylate is even more preferred.

[0031] When the addition polymerization resin segment contains a structural unit derived from a (meth)acrylic acid ester, the content of the (meth)acrylic acid ester in the raw material monomers of the addition polymerization resin segment is preferably 5% by mass or more, more preferably 10% by mass or more, even more preferably 15% by mass or more, and preferably 50% by mass or less, more preferably 35% by mass or less, even more preferably 25% by mass or less.

[0032] The total amount of the styrene compound and (meth)acrylic acid ester in the raw material monomers of the addition polymerization resin segment is preferably 80% by mass or more, more preferably 90% by mass or more, even more preferably 95% by mass or more, and still more preferably 100% by mass.

[0033] The composite resin preferably has a constitutional unit derived from a bireactive monomer bonded via a covalent bond to a polyester resin segment and an addition polymerized resin segment. The term "structural unit derived from a bireactive monomer" refers to a unit formed by reaction of a functional group and an addition polymerizable group of a bireactive monomer. An example of the addition polymerizable group is a carbon-carbon unsaturated bond (ethylenically unsaturated bond). 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 addition-polymerizable monomers having a carboxy group include acrylic acid, methacrylic acid, fumaric acid, and maleic acid. Among these, from the viewpoint of reactivity in both polycondensation reactions and addition polymerization reactions, acrylic acid and methacrylic acid are preferred, and acrylic acid is more preferred. When the bireactive monomer is an addition-polymerizable monomer having a carboxy group, the amount of the constitutional unit derived from the bireactive monomer is preferably 1 mol part or more, more preferably 5 mol parts or more, even more preferably 8 mol parts or more, and 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.

[0034] The content of the polyester resin segment in the composite resin is preferably 50% by mass or more, more preferably 60% by mass or more, even more preferably 70% by mass or more, and preferably 95% by mass or less, more preferably 90% by mass or less, even more preferably 85% by mass or less, based on 100% by mass of the total amount of the polyester resin segment and the addition polymerization resin segment. The constitutional unit derived from the bireactive monomer is referred to as the polyester resin segment.

[0035] The content of the addition polymerization resin segment in the composite resin 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 40% by mass or less, even more preferably 30% by mass or less, based on 100% by mass of the total amount of the polyester resin segment and the addition polymerization resin segment.

[0036] The amount of the bireactive monomer-derived structural units in the composite resin is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, even more preferably 0.8% by mass or more, and is preferably 8% by mass or less, more preferably 5% by mass or less, even more preferably 2% by mass or less, based on 100% by mass of the total amount of the polyester resin segment and the addition polymerization resin segment.

[0037] The total amount of polyester resin segments and addition polymerization resin segments in the composite resin is preferably 80% by mass or more, 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.

[0038] The above amounts are calculated based on the ratio of the amounts of the polyester resin segment, raw material monomer for the addition polymerization resin segment, bireactive monomer, and radical polymerization initiator, and the mass of the polyester resin segment, etc. is based on the mass excluding the mass of water produced by polycondensation. When a radical polymerization initiator is used, the mass of the radical polymerization initiator is calculated by including it in the mass of the addition polymerization resin segment.

[0039] (Method for producing amorphous polyester resin A) <Method for producing polyester resin> The polyester resin can be produced, for example, by polycondensing raw material monomers containing an alcohol component and a carboxylic acid component. The polycondensation of the alcohol component and the carboxylic acid component can be carried out, for example, in an inert gas atmosphere, in the presence of an esterification catalyst, an esterification promoter, a polymerization inhibitor, etc., as necessary, at a temperature of about 120°C or higher and 250°C or lower. Examples of the esterification catalyst include tin compounds such as dibutyltin oxide and tin(II) di(2-ethylhexanoate), and titanium compounds such as titanium diisopropoxybis(triethanolaminate). Examples of the esterification co-catalyst that can be used together with the esterification catalyst include gallic acid (3,4,5-trihydroxybenzoic acid). The amount of the esterification catalyst used is preferably 0.01 parts by mass or more and 10 parts by mass or less relative to 100 parts by mass of the total amount of the alcohol component and the carboxylic acid component, which are raw material monomers for the polyester resin. The amount of the esterification promoter used is preferably 0.001 part by mass or more and 1 part by mass or less relative to 100 parts by mass of the total amount of the alcohol component and the carboxylic acid component. Furthermore, examples of the polymerization inhibitor include radical polymerization inhibitors such as 4-tert-butylcatechol. When a polymerization inhibitor is used, the amount of the polymerization inhibitor used is preferably 0.001 part by mass or more and 1 part by mass or less per 100 parts by mass of the total amount of the alcohol component and the carboxylic acid component.

[0040] <Composite resin manufacturing method> The composite resin may be produced, for example, by a method including a step A of polycondensing an alcohol component and a carboxylic acid component, and a step B of addition-polymerizing raw material monomers of the addition-polymerized resin segment and a bireactive monomer. 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. A preferred method is to subject a portion of the carboxylic acid component to a polycondensation reaction in step A, then carry out step B, and then add the remainder of the carboxylic acid component to the polymerization system to further promote the polycondensation reaction of step A and the polycondensation reaction with, for example, a carboxy group possessed by the bireactive monomer or the constituent unit derived from the bireactive monomer.

[0041] In step A, if necessary, the esterification catalyst and esterification promoter described in the above method for producing a polyester resin may be used in the same amounts to carry out polycondensation. When a monomer having an unsaturated bond such as fumaric acid is used in polycondensation, the polymerization inhibitor described in the above method for producing the polyester resin may be used in the same amount as above, if necessary. The temperature of the polycondensation reaction is preferably 120° C. or higher, more preferably 150° 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.

[0042] Examples of the radical polymerization initiator for the addition polymerization in step B 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 with respect to 100 parts by mass of the raw material monomer of the addition polymerization resin segment. The temperature of the addition polymerization is preferably 110°C or higher, more preferably 130°C or higher, and preferably 240°C or lower, more preferably 230°C or lower, and even more preferably 220°C or lower.

[0043] (Physical properties of amorphous polyester resin A) The softening point of Resin A is preferably 70°C or higher, more preferably 85°C or higher, even more preferably 95°C or higher, and preferably 140°C or lower, more preferably 130°C or lower, even more preferably 120°C or lower. The glass transition temperature of Resin A is preferably 35°C or higher, more preferably 40°C or higher, even more preferably 45°C or higher, and preferably 75°C or lower, more preferably 70°C or lower, even more preferably 65°C or lower.

[0044] The acid value of Resin A is preferably 5 mgKOH / g or more, more preferably 10 mgKOH / g or more, even more preferably 15 mgKOH / g or more, and preferably 35 mgKOH / g or less, more preferably 30 mgKOH / g or less, even more preferably 25 mgKOH / g or less.

[0045] The softening point, glass transition temperature, and acid value of Resin A can be appropriately adjusted by the type and amount 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 A are used in combination, it is preferable that at least one of them has the above-mentioned ranges for each of the physical properties.Moreover, it is more preferable that the softening point, glass transition temperature, and acid value obtained as a mixture of these resins each have the above-mentioned ranges.

[0046] (styrene acrylic resin) Styrene-acrylic resin is an addition polymer of a styrene-based compound and alkyl (meth)acrylate. As the styrene-based compound, the styrene-based compounds in the addition polymerization resin segment described above can be used, with styrene being preferred.

[0047] The content of styrene-based compounds in the raw material monomers of the styrene-acrylic resin is preferably 65% ​​by mass or more, more preferably 70% by mass or more, even more preferably 75% by mass or more, and preferably 95% by mass or less, more preferably 90% by mass or less, even more preferably 85% by mass or less.

[0048] The number of carbon atoms in the alkyl group in the alkyl (meth)acrylate is preferably 1 or more, more preferably 3 or more, and preferably 24 or less, more preferably 22 or less, and even more preferably 20 or less. Examples of alkyl (meth)acrylates include methyl (meth)acrylate, ethyl (meth)acrylate, 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, preferably (iso- or tertiary)butyl (meth)acrylate, and more preferably n-butyl acrylate.

[0049] The content of alkyl (meth)acrylate in the raw material monomers of the styrene-acrylic resin is preferably 5% by mass or more, more preferably 10% by mass or more, even more preferably 15% by mass or more, and preferably 35% by mass or less, more preferably 30% by mass or less, even more preferably 25% by mass or less.

[0050] The styrene-acrylic resin may contain structural units derived from raw material monomers other than styrene-based compounds and alkyl (meth)acrylates. Examples of raw material monomers other than styrene-based compounds and alkyl (meth)acrylates include (meth)acrylic acid esters such as 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 methyl vinyl ether; vinylidene halides such as vinylidene chloride; and N-vinyl compounds such as N-vinylpyrrolidone. The polymerization form of the styrene-acrylic resin may be either a random or block polymerization form.

[0051] (Method of manufacturing styrene acrylic resin) The styrene-acrylic resin can be produced by addition polymerization of raw material monomers in the same manner as in step B above.

[0052] (Physical properties of styrene acrylic resin) The softening point of the styrene acrylic resin is preferably 70°C or higher, more preferably 85°C or higher, and even more preferably 95°C or higher, and is preferably 140°C or lower, more preferably 130°C or lower, and even more preferably 120°C or lower. The glass transition temperature of the styrene-acrylic resin is preferably 35°C or higher, more preferably 40°C or higher, even more preferably 45°C or higher, and preferably 75°C or lower, more preferably 70°C or lower, even more preferably 65°C or lower.

[0053] The softening point and glass transition temperature of the styrene-acrylic resin can be appropriately adjusted by the type and amount 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 method described in the examples. When two or more styrene-acrylic resins are used in combination, it is preferable that the softening point and glass transition temperature of the resulting mixture are within the above ranges.

[0054] (Crystalline polyester resin C) The crystalline polyester resin C is a polycondensate of an alcohol component and a carboxylic acid component, and satisfies at least one of the following conditions 1 and 2, and the ester group concentration of the crystalline polyester resin C is 6.0 mmol / g or more and 10.5 mmol / g or less. (Condition 1) The alcohol component contains 80 mol% or more of ethylene glycol. (Condition 2) The carboxylic acid component contains 80 mol % or more of α,ω-aliphatic dicarboxylic acids having 4 carbon atoms. The crystalline polyester resin C preferably satisfies condition 1 from the viewpoint of obtaining a printed matter that is excellent in bending resistance and document offset resistance. Hereinafter, the crystalline polyester resin C may be referred to as "resin C."

[0055] The alcohol component and the carboxylic acid component will be described below. The alcohol component contains an aliphatic diol from the viewpoint of crystallinity. The carbon number of the aliphatic diol is preferably 2 or more and preferably 16 or less. As the aliphatic diol, a linear aliphatic diol is preferred, such as 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, ethylene glycol is preferred. Condition 1 is satisfied when the alcohol component contains 80 mol % or more of ethylene glycol.

[0056] The amount of the aliphatic diol in the alcohol component is preferably 80 mol% or more, more preferably 85 mol% or more, even more preferably 90 mol% or more, still more preferably 95 mol% or more, and is 100 mol% or less, preferably 100 mol%.

[0057] When resin C satisfies condition 1, the amount of ethylene glycol in the alcohol component is 80 mol% or more, preferably 85 mol% or more, more preferably 90 mol% or more, even more preferably 95 mol% or more, and is 100 mol% or less, preferably 100 mol%.

[0058] The alcohol component may contain an alcohol component other than the aliphatic diol. Examples of other alcohol components include monoalcohols such as lauryl alcohol and stearyl alcohol; alkylene oxide adducts of aromatic diols such as alkylene oxide adducts of bisphenol A; and trihydric or higher alcohols such as glycerin, pentaerythritol, and trimethylolpropane.

[0059] The carboxylic acid component contains an aliphatic dicarboxylic acid from the viewpoint of crystallinity, and the aliphatic dicarboxylic acid is preferably an α,ω-aliphatic dicarboxylic acid. The number of carbon atoms in the aliphatic dicarboxylic acid is preferably 4 or more and preferably 16 or less. Specific examples of the aliphatic dicarboxylic acid include succinic acid, fumaric acid, maleic acid, adipic acid, sebacic acid, 1,11-undecanedioic acid, 1,12-dodecanedioic acid, 1,14-tetradecanedioic acid, and 1,16-hexadecanedioic acid. Among these, α,ω-aliphatic dicarboxylic acids having 4 carbon atoms are preferred. Condition 2 is satisfied when the carboxylic acid component contains 80 mol % or more of α,ω-aliphatic dicarboxylic acids having 4 carbon atoms.

[0060] The amount of the aliphatic dicarboxylic acid in the carboxylic acid component is preferably 80 mol % or more, more preferably 85 mol % or more, even more preferably 90 mol % or more, still more preferably 95 mol % or more, and 100 mol % or less.

[0061] When Resin C satisfies Condition 2, the amount of the α,ω-aliphatic dicarboxylic acid having 4 carbon atoms in the carboxylic acid component is 80 mol% or more, preferably 85 mol% or more, and 100 mol% or less, preferably 95 mol% or less.

[0062] The carboxylic acid component may include a monocarboxylic acid, which preferably has 6 or more carbon atoms, more preferably 8 or more carbon atoms, even more preferably 12 or more carbon atoms, and preferably has 24 or less carbon atoms, more preferably 22 or less carbon atoms, and even more preferably 20 or less carbon atoms. Examples of monocarboxylic acids include caprylic acid, pelargonic acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, lignoceric acid, etc. Among these, preferred are caprylic acid, lauric acid, stearic acid, and behenic acid, and from the viewpoint of obtaining printed matter that is excellent in folding resistance and document offset resistance, more preferred are stearic acid and behenic acid, and even more preferred is stearic acid. When the carboxylic acid component contains a monocarboxylic acid, the amount of the monocarboxylic 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 25 mol% or less, more preferably 20 mol% or less, even more preferably 15 mol% or less. The carboxylic acid component may contain other carboxylic acid components different from aliphatic dicarboxylic acids and monocarboxylic acids, such as aromatic dicarboxylic acids such as terephthalic acid and isophthalic acid, and trivalent or higher polycarboxylic acids such as trimellitic acid.

[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] From the viewpoint of obtaining printed matter having excellent folding resistance and document offset resistance, Resin C has an ester group concentration of 6.0 mmol / g or more, preferably 6.3 mmol / g or more, more preferably 6.6 mmol / g or more, and 10.5 mmol / g or less, preferably 9.0 mmol / g or less, more preferably 8.5 mmol / g or less, and even more preferably 8.2 mmol / g or less. The ester group concentration of Resin C is calculated by the following formula.

[0065]

number

[0066] (Method for producing crystalline polyester resin C) Resin C can be produced, for example, in the same manner as the "method for producing polyester resin" in the "method for producing amorphous polyester resin A" described above.

[0067] (Physical properties of crystalline polyester resin C) The softening point of Resin C is preferably 50°C or higher, more preferably 55°C or higher, and even more preferably 60°C or higher, and from the viewpoint of further improving low-temperature fixability, it is preferably 130°C or lower, more preferably 120°C or lower, and even more preferably 100°C or lower. The melting point of Resin C is preferably 50°C or higher, more preferably 55°C or higher, and even more preferably 60°C or higher, and from the viewpoint of further improving low-temperature fixability, it is preferably 110°C or lower, more preferably 100°C or lower, and even more preferably 95°C or lower.

[0068] The acid value of Resin C is preferably 2 mgKOH / g or more, more preferably 4 mgKOH / g or more, and preferably 25 mgKOH / g or less, more preferably 20 mgKOH / g or less, and even more preferably 15 mgKOH / g or less.

[0069] The ester group concentration, softening point, melting point, and acid value of Resin C 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 the softening point, melting point, and acid value are determined by the methods described in the Examples below. When two or more types of Resin C are used in combination, it is preferable that the ester group concentration, softening point, melting point, and acid value obtained as a mixture thereof each fall within the above-mentioned ranges.

[0070] <Polyurethane Resin U> The polyurethane resin U is a polyaddition product of a polyol component and an isocyanate component including a polyisocyanate.

[0071] (Physical properties of polyurethane resin U) From the viewpoint of obtaining printed matter that is excellent in bending resistance and document offset resistance, the breaking elongation of polyurethane resin U is preferably 3% or more, more preferably 100% or more, even more preferably 250% or more, even more preferably 500% or more, and is preferably 1500% or less, more preferably 1350% or less, even more preferably 1200% or less.

[0072] From the viewpoint of obtaining printed matter having excellent bending resistance and document offset resistance, the glass transition temperature of polyurethane resin U is preferably −30° C. or higher, more preferably −25° C. or higher, even more preferably 0° C. or higher, and is preferably 95° C. or lower, more preferably 85° C. or lower, even more preferably 80° C. or lower.

[0073] The breaking elongation and glass transition temperature of the polyurethane resin U can be adjusted appropriately by adjusting the types and amounts of raw material monomers used, as well as production conditions such as reaction temperature, reaction time, and cooling rate. When two or more polyurethane resins U are used in combination, the resulting mixture preferably has a breaking elongation within the above-mentioned preferred ranges, and a glass transition temperature within the above-mentioned preferred ranges. The mixture may be a mixture of a polyurethane resin having a breaking elongation and a glass transition temperature within the above-mentioned preferred ranges, and a polyurethane resin having a breaking elongation outside the above-mentioned preferred ranges and / or a glass transition temperature outside the above-mentioned preferred ranges. The breaking elongation and glass transition temperature of the polyurethane resin U can be determined by the method described in the examples.

[0074] (Structure of Polyurethane Resin U) From the viewpoint of obtaining printed matter that has excellent resistance to folding and document offset, polyurethane resin U preferably contains at least one selected from polyether-based polyurethane resins, polycarbonate-based polyurethane resins, and polyester-based polyurethane resins, more preferably contains at least one selected from polyether-based polyurethane resins and polycarbonate-based polyurethane resins, and even more preferably contains a polyether-based polyurethane resin.

[0075] (Polyol component) <Polyether polyol> The polyether polyol that is the polyol component of the polyether polyurethane resin may have hydroxy groups at both ends of the main chain, and for example, a compound represented by the following general formula (P1) may be used.

[0076] [ka]

[0077] In general formula (P1), L 1 represents an alkylene group, and n1 is the number of repeats. 1 The alkylene groups represented by may be the same or different. The alkylene group may be either linear or branched, and has preferably 2 or more, more preferably 3 or more, and even more preferably 4 or more carbon atoms, and preferably 8 or less, more preferably 7 or less, and even more preferably 6 or less.

[0078] Examples of the polyether polyol represented by general formula (P1) include polyethylene glycol, polypropylene glycol, polybutylene glycol, and polytetramethylene glycol.

[0079] The polyether polyol may be either a synthetic product or a commercially available product. Synthetic products are obtained, for example, by ring-opening polymerization of a cyclic ether compound using a compound having an active hydrogen atom as a catalyst.

[0080] <Polycarbonate polyol> The polycarbonate polyol that is the polyol component of the polycarbonate-based polyurethane resin may have hydroxy groups at both ends of the main chain, and for example, a compound represented by the following general formula (P2) may be used.

[0081] [ka]

[0082] In general formula (P2), L 2 and L 3 Each independently represents an alkylene group. n2 is the number of repeats. 2 The alkylene groups represented by may be the same or different. The alkylene groups may be linear or branched.

[0083] The polycarbonate polyol may be either a synthetic product or a commercially available product. Synthetic products are obtained by reacting diols with dialkyl carbonates or cyclic carbonates.

[0084] <Polyester polyol> The polyester polyol that is the polyol component of the polyester polyurethane resin may have, for example, hydroxy groups at both ends of the main chain.

[0085] (Isocyanate component) Examples of polyisocyanates include aliphatic diisocyanates, aromatic diisocyanates, and prepolymer, isocyanurate, urea, and carbodiimide modified products of these diisocyanates. Examples of the aliphatic diisocyanate include alicyclic diisocyanates and chain aliphatic diisocyanates. Examples of alicyclic diisocyanates include isophorone diisocyanate, cyclohexane-1,4-diisocyanate, 4-methyl-1,3-cyclohexylene diisocyanate, 1,2-bis(isocyanatomethyl)cyclohexane, and 4,4'-dicyclohexylmethane diisocyanate. Examples of the chain aliphatic diisocyanate include linear aliphatic diisocyanates and branched aliphatic diisocyanates, and more specific examples include tetramethylene diisocyanate, hexamethylene diisocyanate, dodecamethylene diisocyanate, and 2,4,4-trimethylhexamethylene diisocyanate. Examples of aromatic diisocyanates include m-phenylene diisocyanate, p-phenylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 1,3-xylylene diisocyanate, 1,4-xylylene diisocyanate, tetramethylxylylene diisocyanate, 1,5-naphthylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4'-dibenzyl isocyanate, tetraalkyldiphenylmethane diisocyanate, and 3,3'-dimethyl-4,4'-biphenylene diisocyanate. The isocyanate component may contain a monoisocyanate.

[0086] The polyurethane resin U can be either a synthetic product or a commercially available product. Synthetic products can be obtained by polyaddition of the above-mentioned polyol component and isocyanate component by a conventional method. Commercially available products include, for example, Takelac W6061 (polyether-based polyurethane resin, elongation at break 1000%, glass transition temperature 25°C) and Takelac W5661 (polyether-based polyurethane resin, elongation at break 600%, glass transition temperature 70°C) manufactured by Mitsui Chemicals, Inc., WBR-016U (polyether-based polyurethane resin, elongation at break 760%, glass transition temperature 15°C) manufactured by Taisei Fine Chemical Co., Ltd., and NeoRez manufactured by Covestró AG. Examples of such resins include R600 (polyether-based polyurethane resin, elongation at break 970%, glass transition temperature 10°C), ADEKA Corporation's Bontitor HUX-564 (polycarbonate-based polyurethane resin, elongation at break 700%, glass transition temperature 36°C), Dai-ichi Kogyo Seiyaku Co., Ltd.'s Superflex 460 (polycarbonate-based polyurethane resin, elongation at break 750%, glass transition temperature -21°C), DIC Corporation's Hydran AP-10 (polyester-based polyurethane resin, elongation at break 300%, glass transition temperature 27°C), and Dai-ichi Kogyo Seiyaku Co., Ltd.'s Superflex 210 (polyester-based polyurethane resin, elongation at break 5%, glass transition temperature 41°C).

[0087] <Resin content> From the viewpoint of obtaining printed matter that is excellent in bending resistance and document offset resistance, the content of amorphous resin A in the toner particles is preferably 40% by mass or more, more preferably 50% by mass or more, even more preferably 55% by mass or more, and is preferably 80% by mass or less, more preferably 75% by mass or less, even more preferably 70% by mass or less.

[0088] The total content of the amorphous polyester resin A and the styrene acrylic resin in the amorphous resin A is preferably 90% by mass or more, more preferably 95% by mass or more, and even more preferably 98% by mass or more, from the viewpoint of obtaining printed matter that is excellent in bending resistance and document offset resistance, and is 100% by mass or less, and preferably 100% by mass.

[0089] From the viewpoint of obtaining printed matter that is excellent in bending resistance and document offset resistance, the content of resin C in the toner particles is preferably 2% by mass or more, more preferably 5% by mass or more, even more preferably 8% by mass or more, and is preferably 30% by mass or less, more preferably 25% by mass or less, even more preferably 20% by mass or less.

[0090] In the toner particles, the mass ratio of resin C to amorphous resin A [resin C / amorphous resin A] is preferably 5 / 95 or more, more preferably 8 / 92 or more, even more preferably 12 / 88 or more, and is preferably 40 / 60 or less, more preferably 30 / 70 or less, even more preferably 25 / 75 or less.

[0091] The total content of the polyether-based polyurethane resin, polycarbonate-based polyurethane resin, and polyester-based polyurethane resin in the polyurethane resin U is preferably 80% by mass or more, more preferably 90% by mass or more, even more preferably 95% by mass or more, and is 100% by mass or less, preferably 100% by mass.

[0092] In the toner particles, the proportion of polyurethane resin U in the total content of amorphous resin A, resin C, and polyurethane resin U (100 x mass of polyurethane resin U / total mass of amorphous resin A, resin C, and polyurethane resin U) is preferably 3% by mass or more, more preferably 7% by mass or more, even more preferably 10% by mass or more, from the viewpoint of obtaining printed matter that is excellent in bending resistance and document offset resistance, and is preferably 50% by mass or less, more preferably 40% by mass or less, even more preferably 30% by mass or less, even more preferably 20% by mass or less.

[0093] From the viewpoint of obtaining printed matter that is excellent in bending resistance and document offset resistance, the content of polyurethane resin U in the toner particles is preferably 2% by mass or more, more preferably 5% by mass or more, even more preferably 7% by mass or more, and is preferably 40% by mass or less, more preferably 30% by mass or less, even more preferably 20% by mass or less, even more preferably 15% by mass or less.

[0094] <Coloring agent> The toner particles preferably contain a colorant, and as the colorant, any of dyes, pigments, etc. that are used as colorants for toners can be used. Examples of colorants include carbon black, phthalocyanine blue, permanent brown FG, brilliant fast scarlet, pigment green B, rhodamine-B base, solvent red 49, solvent red 146, solvent blue 35, quinacridone, carmine 6B, disazo yellow, and pigment red 269. The toner may be either black toner or a color toner other than black. From the viewpoint of image density, the content of the colorant in the toner particles is preferably 1% by mass or more, more preferably 2% by mass or more, even more preferably 3% by mass or more, and is preferably 15% by mass or less, more preferably 10% by mass or less, even more preferably 8% by mass or less.

[0095] <Release agent> The toner particles preferably contain a release agent. Examples of the release agent include hydrocarbon waxes such as polypropylene wax, polyethylene wax, ethylene-propylene 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.

[0096] The melting point of the release agent is preferably 60°C or higher, more preferably 70°C or higher, and preferably 160°C or lower, more preferably 140°C or lower, and even more preferably 120°C or lower. The content of the release agent in the toner particles is preferably 1% by mass or more, more preferably 2% by mass or more, and even more preferably 5% by mass or more, and is preferably 15% by mass or less, and more preferably 10% by mass or less.

[0097] In addition, the toner particles 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.

[0098] [Physical Properties of Toner Particles] Volume median particle size D of toner particles 50 From the viewpoint of obtaining a printed coating film with good image quality and further improving the cleaning properties of the toner, the thickness 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 7 μm or less.

[0099] The CV value of the toner particles is preferably 10% or more, more preferably 12% or more, and even more preferably 14% or more, from the viewpoint of improving toner productivity, and is preferably 45% or less, more preferably 40% or less, and even more preferably 35% or less, from the viewpoint of obtaining good image quality.

[0100] The circularity of the toner particles is preferably 0.955 or more, more preferably 0.960 or more, from the viewpoint of obtaining a printed coating film (image) with good image quality, and is preferably 0.990 or less, more preferably 0.985 or less, and even more preferably 0.980 or less, from the viewpoint of cleanability. Volume median particle size D of toner particles 50 The CV value can be measured by the method described in the Examples. The circularity of the toner particles can be measured in the same manner as the circularity of the fused particles.

[0101] [Method of manufacturing electrostatic image developing toner] The method for producing the toner for developing electrostatic images of the present invention (hereinafter also referred to as the "toner production method") may be any known method such as a melt-kneading method, an emulsion phase inversion method, a suspension polymerization method, or an emulsion aggregation method, and the emulsion aggregation method is preferred.

[0102] [Emulsification aggregation method] The emulsion aggregation method includes a step of aggregating and fusing resin particles containing the same or different resins in an aqueous medium. The aggregated particles obtained in the step of aggregating resin particles include aggregated particles 1 obtained by aggregating resin particles in an aqueous medium, and aggregated particles 2 obtained by using aggregated particles 1 as cores and attaching shell resin particles to these cores in an aqueous medium to cause aggregation. The term "aggregated particles" simply refers to aggregated particles 1 or 2.

[0103] <Step of aggregating resin particles> In the step of aggregating the resin particles, resin particles containing the same or different particles of resin are aggregated in an aqueous medium to obtain aggregated particles 1. In addition to the resin particles, it is preferable to further aggregate a colorant and a release agent, and it is preferable to mix an aqueous dispersion of resin particles (resin particle dispersion), an aqueous dispersion of colorant particles (colorant particle dispersion), and an aqueous dispersion of release agent particles (release agent particle dispersion) and aggregate these particles to obtain aggregated particles 1.

[0104] In the present invention, the aqueous medium used in the aqueous dispersion is a medium containing water as the 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. The water is preferably deionized water or distilled water. Examples of components other than water that can constitute the aqueous medium together with water include water-soluble organic solvents 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.

[0105] (Method of manufacturing resin particle dispersion) The resin particles may be prepared as a resin particle dispersion containing the resin in the same or different particles.

[0106] Dispersion can be carried out using known methods, but when the resin is a polyester resin, it is preferable to disperse it by a phase inversion emulsification method. Examples of the phase inversion emulsification method include a method in which an aqueous medium is added to an organic solvent solution of the resin or a molten resin to perform phase inversion emulsification. A method in which an aqueous medium is added to an organic solvent solution of the resin to perform phase inversion emulsification is preferred. The organic solvent used for phase inversion emulsification is not particularly limited as long as it dissolves the resin and is water-soluble, and examples thereof include methyl ethyl ketone and ethyl acetate. A neutralizing agent may be added to the organic solvent solution of amorphous resin A and / or resin C. Examples of neutralizing agents include basic substances. Examples of basic substances include alkali metal hydroxides such as sodium hydroxide and potassium hydroxide; and nitrogen-containing basic substances such as ammonia, trimethylamine, and diethanolamine. Among these, alkali metal hydroxides such as sodium hydroxide and potassium hydroxide are preferred. The degree of neutralization of the amorphous resin A and / or resin C that constitute the resin particles is preferably 40 mol% or more, more preferably 45 mol% or more, even more preferably 50 mol% or more, and preferably 100 mol% or less, more preferably 80 mol% or less, even more preferably 70 mol% or less. The degree of neutralization of the amorphous resin A and / or resin C constituting the resin particles can be calculated by the following formula. Degree of neutralization (mol%) = [{weight of neutralizing agent added (g) / equivalent weight of neutralizing agent} / [{weighted average acid value of resin constituting resin particles (mg KOH / g) × weight of resin constituting resin particles (g)} / (56 × 1000)]] × 100

[0107] 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 resin particles containing a resin, the temperature of the organic solvent solution when adding an aqueous medium is preferably equal to or higher than the glass transition temperature of the resin, more preferably equal to or higher than 60°C, even more preferably equal to or higher than 65°C, and is preferably equal to or lower than 100°C, more preferably equal to or lower than 95°C, even more preferably equal to or lower than 90°C.

[0108] After the phase inversion emulsification, the organic solvent may be removed from the resulting dispersion by distillation or the like, if necessary. Alternatively, the resin particles may be isolated by filtration or the like. It is preferable to use an aqueous dispersion of resin particles obtained by removing the organic solvent from the dispersion obtained after the phase inversion emulsification. 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.

[0109] Volume median particle size D of polyester resin particles 50 is preferably 0.03 μm or more, more preferably 0.06 μm or more, even more preferably 0.09 μm or more, and is preferably 1 μm or less, more preferably 0.5 μm or less, even more preferably 0.2 μm or less. The volume median particle diameter D50 of the polyurethane resin particles is preferably 0.01 μm or more, more preferably 0.03 μm or more, and preferably 1 μm or less, more preferably 0.5 μm or less, and even more preferably 0.2 μm or less. The CV value of the resin particles is preferably 10% or more, more preferably 20% or more, and is preferably 40% or less, more preferably 35% or less. Resin particle volume median diameter D 50 The CV value is measured by the method described in the Examples.

[0110] From the viewpoint of improving toner productivity and dispersion stability of the resin particle dispersion, the solid content concentration of the resin particle dispersion 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 40% by mass or less, even more preferably 35% by mass or less. The solid content is the total amount of non-volatile components.

[0111] (Method of manufacturing colorant particle dispersion) The colorant particles are preferably obtained as a dispersion of colorant particles by dispersing a colorant and an aqueous medium using a disperser such as a homogenizer, an ultrasonic disperser, etc. From the viewpoint of improving the dispersion stability of the colorant, the dispersion is preferably carried out in the presence of a surfactant or an addition polymer (hereinafter, the addition polymer used to disperse the colorant is also referred to as "addition polymer E"). Examples of the surfactant include a nonionic surfactant, an anionic surfactant, and a cationic surfactant. The addition polymer E preferably has a constituent unit derived from an addition polymerizable monomer a having an aromatic group, and preferably further contains at least one selected from the group consisting of an addition polymerizable monomer b having an ionic group, an addition polymerizable monomer c having a polyalkylene oxide group, and a macromonomer d. For details of a colorant particle dispersion using the addition polymer E, see JP 2021-26129 A.

[0112] From the viewpoint of image density of printed matter, the content of the colorant in the colorant particle dispersion is preferably 1% by mass or more, more preferably 3% by mass or more, even more preferably 5% by mass or more, and is preferably 40% by mass or less, more preferably 30% by mass or less, even more preferably 20% by mass or less. The solid content of the colorant particle dispersion is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 15% by mass or more, and is preferably 40% by mass or less, and more preferably 30% by mass or less.

[0113] Volume median particle size D of colorant particles 50 From the viewpoint of improving the dispersibility of the colorant in the toner, the particle size is preferably 0.05 μm or more, more preferably 0.08 μm or more, and is preferably 0.4 μm or less, more preferably 0.3 μm or less, and even more preferably 0.25 μm or less. From the viewpoint of improving the dispersibility of the colorant in the toner, the CV value of the colorant particles is preferably 10% or more, more preferably 15% or more, and is preferably 40% or less, more preferably 35% or less, and even more preferably 30% or less. Volume median particle size D of colorant particles 50 and CV values ​​are measured by the methods in the Examples.

[0114] (Method of producing release agent particle dispersion) The release agent particle dispersion can be obtained using a surfactant, but is preferably obtained by mixing the release agent and resin particles. By preparing the release agent particles using the release agent and resin particles, the release agent particles are stabilized by the resin that constitutes the resin particles, and it becomes possible to disperse the release agent in an aqueous medium without using a surfactant. It is believed that the release agent particle dispersion has a structure in which a large number of resin particles adhere to the surfaces of the release agent particles. The resin constituting the resin particles 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. For details about the release agent particle dispersion and the composite resin D, see JP 2021-182045 A. The aforementioned amorphous polyester resin A may also be used.

[0115] Volume median particle size D of release agent particles 50 From the viewpoint of obtaining uniform aggregated particles 1 by aggregation, the average particle size is preferably 0.05 μm or more, more preferably 0.1 μm or more, even more preferably 0.2 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 15% or more, and is preferably 40% or less, more preferably 35% or less, and even more preferably 30% or less. Volume median particle size D of release agent particles 50 The CV value is measured by the method described in the Examples.

[0116] <Surfactants> In the step of aggregating the resin particles, dispersions of the respective particles are mixed to prepare a mixed dispersion, and the process may be carried out in the presence of a surfactant in order to improve the dispersion stability of the resin particles, release agent particles, colorant particles, etc. 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 total amount used is preferably 0.1 parts by mass or more, more preferably 0.3 parts by mass or more, and even more preferably 0.5 parts by mass or more, per 100 parts by mass of the total amount of resin particles, and is preferably 10 parts by mass or less, more preferably 5 parts by mass or less.

[0117] <Flocculant> In the step of aggregating the resin particles, it is preferable to add an aggregating agent from the viewpoint of efficient aggregation. Examples of the flocculant include cationic surfactants such as quaternary salts, organic flocculants such as polyethyleneimine, and inorganic flocculants. Examples of the inorganic flocculant include 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 divalent or higher metal complexes. From the viewpoint of improving the aggregating property and obtaining uniform aggregated particles 1, inorganic aggregating agents having a valence of 1 to 5 are preferred, inorganic metal salts having a valence of 1 to 2 and inorganic ammonium salts are more preferred, inorganic ammonium salts are even more preferred, and ammonium sulfate is even more preferred.

[0118] For example, 10 to 50 parts by mass of the aggregating agent is added to a mixed dispersion of resin particles, release agent particles, and colorant particles at a temperature of 0° C. to 40° C., relative to a total of 100 parts by mass of the resin particles, and the resin particles, release agent particles, and colorant particles are aggregated in an aqueous medium to obtain aggregated particles 1. From the viewpoint of promoting aggregation, it is preferable to increase the temperature of the dispersion after adding the aggregating agent.

[0119] Methods for stopping aggregation include cooling the dispersion, adding an aggregation terminator, and diluting the dispersion. From the viewpoint of reliably preventing unnecessary aggregation, a method of stopping aggregation by adding an aggregation terminator is preferred. Furthermore, when a step of aggregating shell resin particles is included for the purpose of producing a toner having a core-shell structure, the step of aggregating shell resin particles may be performed when aggregated particles 1 have grown to an appropriate particle size without terminating the aggregation. Volume median particle size D of aggregated particles 1 50 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 7 μm or less. In the present invention, it is preferable to have a step of adhering and aggregating shell resin particles to the obtained aggregated particles 1 as cores to obtain aggregated particles 2. By having a step of aggregating shell resin particles, it is possible to obtain toner particles having a core-shell structure. The shell resin particles are preferably made of an amorphous resin, more preferably an amorphous polyester resin, and even more preferably the resin A described above. The shell resin particle dispersion liquid can be obtained by the same method as the above-mentioned method for producing the resin particle dispersion liquid. From the viewpoint of low-temperature fixability of the toner, the mass ratio of the shell resin particles to the mass of the aggregated particles 1 [shell resin particles / aggregated particles 1] is preferably 1 / 99 or more, more preferably 3 / 97 or more, even more preferably 5 / 95 or more, and is preferably 20 / 80 or less, more preferably 15 / 85 or less, even more preferably 10 / 90 or less. When the toner manufacturing method includes a step of aggregating shell resin particles, it is preferable to stop the aggregation in the step when the aggregated particles 2 have grown to a particle size appropriate for toner particles, and a method of stopping the aggregation by adding an aggregation terminator is preferred.

[0120] <Aggregation stopper> The aggregation terminator is preferably a surfactant, more preferably an anionic surfactant. Examples of anionic surfactants include alkylbenzenesulfonates, alkyl sulfates, alkyl ether sulfates, polyoxyalkylene alkyl ether sulfates, arylsulfonates, and arylsulfonic acid-formalin condensates, and are preferably alkali metal salts of arylsulfonic acid-formalin condensates, and more preferably sodium salts of naphthalenesulfonic acid-formalin condensates. These may be used alone or in combination. The aggregation terminator may be added in the form of an aqueous solution. The amount of the aggregation terminator added is preferably 1 part by mass or more, more preferably 3 parts by mass or more, relative to 100 parts by mass of aggregated particles immediately before the addition of the aggregation terminator, from the viewpoint of reliably preventing unnecessary aggregation, and is preferably 15 parts by mass or less, more preferably 10 parts by mass or less, from the viewpoint of reducing residue in the toner.

[0121] <Fusion process> In the fusion step, for example, the aggregated particles are fused in an aqueous medium. By fusion, the particles contained in the aggregated particles are fused together to obtain fused particles. In the fusion step, from the viewpoint of improving the fusion properties of the aggregated particles and improving the low-temperature fixability of the toner, the aggregated particles are maintained at a temperature equal to or higher than the glass transition temperature of the resin having the highest glass transition temperature among the amorphous resins contained in the aggregated particles. From the viewpoint of improving the fusion properties of the aggregated particles and improving the productivity of the toner, the holding temperature when fusing the aggregated particles is preferably at least 2°C higher, more preferably at least 3°C ​​higher, and even more preferably at least 5°C higher than the glass transition temperature of the resin having the highest glass transition temperature among the amorphous resins, 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 the resin having the highest glass transition temperature among the amorphous polyester resins. In this case, the time for maintaining the temperature at or above the glass transition temperature of the amorphous resin is preferably 1 minute or more, more preferably 10 minutes or more, even more preferably 30 minutes or more, from the viewpoint of improving the low-temperature fixability of the toner, and is preferably 240 minutes or less, more preferably 180 minutes or less, even more preferably 120 minutes or less, even more preferably 90 minutes or less. It is preferable to maintain the temperature at the above temperature until the desired circularity is achieved.

[0122] The volume median particle size D of the fused particles obtained by fusion 50 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 7 μm or less.

[0123] The circularity of the fused particles obtained by fusion is preferably 0.955 or more, more preferably 0.960 or more, and is preferably 0.990 or less, more preferably 0.985 or less, and even more preferably 0.980 or less. The fusion is preferably terminated after the desired circularity is reached. The circularity is measured by the method described in the Examples.

[0124] <Post-processing process> A post-treatment step may be carried out after the fusion step, and the fused particles are isolated to obtain toner particles. Since the fused particles obtained in the fusion step 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 the solid-liquid separation product. At this time, it is preferable to remove the added surfactant, so washing with an aqueous medium at a temperature below the cloud point of the surfactant is preferable. Washing is preferably performed multiple times. Next, it is preferable to carry out drying. Examples of the drying method include vacuum constant temperature drying, vibration fluidized bed drying, spray drying, freeze drying, and flash jet drying.

[0125] [Melt-kneading method] In the present invention, the melt-kneading method involves, for example, uniformly mixing an amorphous resin A, a crystalline polyester resin C, a polyurethane resin U, and, if necessary, additives such as a colorant and a release agent in a mixer such as a Henschel mixer, and then melt-kneading the mixture in an internal kneader, a single-screw or twin-screw extruder, an open-roll kneader, etc. The mixture is then cooled, pulverized, and classified to produce toner particles.

[0126] <External additives> As described above, it is preferable to use the toner of the present invention in which an external additive has been added to the surface of the toner particles. Examples of external additives include fine particles of inorganic materials such as hydrophobic silica, titanium oxide, alumina, cerium oxide, and carbon black, and fine particles of polymers such as polycarbonate, polymethyl methacrylate, and silicone resin. Among these, hydrophobic silica is preferred. One type of external additive may be used alone, or two or more types may be used. Two or more types of hydrophobic silica having different particle sizes may also be used. When the surface treatment of the toner particles is performed using an external additive, the amount of the external additive added is 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, relative to 100 parts by mass of the toner particles.

[0127] Toners are used to develop electrostatic images in electrophotographic printing. Toners can be used, for example, as a one-component developer or as a two-component developer mixed with a carrier. [Example]

[0128] 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 notation "alkylene oxide (X)" and the like, the number X in parentheses means the average number of moles of alkylene oxide added.

[0129] [Measurement method] [Softening point, crystallinity index, melting point and glass transition temperature of resin] (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 a load of 1.96 MPa was applied by the plunger, and the sample was extruded from a nozzle 1 mm in diameter and 1 mm in length. The plunger depression distance 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" (TA Instruments Japan), 0.02 g of sample was weighed into an aluminum pan and cooled to 0°C at a rate of 10°C / min. The temperature was then held for 1 minute, after which the temperature was raised to 180°C at a rate of 10°C / min and the calorific value was measured. The temperature of the endothermic peak with the largest area was defined 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 sample was weighed into an aluminum pan, heated to 200°C, and cooled from 200°C 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. The temperature of the peak with the largest peak area among the observed endothermic peaks was taken as the maximum endothermic peak temperature (2). For crystalline resins, this peak temperature was taken as the melting point. In the case of an amorphous resin, when a peak is observed, the temperature of the peak is taken as the glass transition temperature. When a step is observed instead of a peak, the temperature at the intersection of the tangent line showing the maximum slope of the curve at the step and an extension of the baseline on the low-temperature side of the step is taken as the glass transition temperature.

[0130] [Acid value of resin] The acid value of the resin was measured according to the neutralization titration method described in JIS K 0070: 1992. The measurement solvent was a mixed solvent of acetone and toluene (acetone:toluene=1:1 (volume ratio)).

[0131] [Ester group concentration] The ester group concentration (mmol / g) of the resin was calculated using the above formula.

[0132] [Melting point of release agent] Using a differential scanning calorimeter "Q100" (TA Instruments Japan Co., Ltd.), 0.02 g of sample was weighed into an aluminum pan, heated to 200°C, and then cooled from 200°C 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.

[0133] [Volume median particle diameter D of resin particles, colorant particles, and release agent particles 50 and CV value) (1) Measuring device: Laser diffraction particle size measuring instrument "LA-920" (manufactured by Horiba Ltd.) (2) Measurement conditions: Put the sample dispersion in a measurement cell, add distilled water, and measure the volume median particle size D at a concentration where the absorbance is in the appropriate range. 50 The volume average particle diameter Dv was measured, and the CV value was calculated according to the following formula. CV value (%) = (standard deviation of particle size distribution / volume average particle size Dv) x 100

[0134] [Solid Content Concentration of Resin Particle Dispersion, Colorant 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 minutes, moisture content fluctuation range 0.05%). The solid content concentration was calculated according to the following formula. Solid concentration (mass%) = 100-moisture (mass%)

[0135] [Volume median particle size of agglomerated particles D 50 〕 Measuring instrument: "Coulter Multisizer (registered trademark) III" (manufactured by Beckman Coulter, Inc.) Aperture diameter: 50 μm 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 again, and the volume median particle size D is calculated from the particle size distribution. 50 asked for.

[0136] [Circularity of fused particles] Measurement equipment: Flow particle image analyzer "FPIA-3000" (Sysmex Corporation) Preparation of dispersion: The dispersion of fused particles was diluted with deionized water to a solids concentration of 0.001 to 0.05% by mass. Measurement mode: HPF measurement mode

[0137] [Volume median particle size D of toner particles 50 and CV value) The measurement device, aperture diameter, analysis software, and electrolyte were determined based on the volume median particle diameter D 50 The same material as that used in the measurement was used. Dispersion: Polyoxyethylene lauryl ether "EMULGEN (registered trademark) 109P" (manufactured by Kao Corporation, HLB (Hydrophile-Lipophile Balance) = 13.6) was dissolved in the electrolyte solution to obtain a dispersion with a concentration of 5 mass %. Dispersion conditions: 10 mg of a measurement sample of dried toner particles was added to 5 mL of the dispersion liquid, and the mixture was dispersed for 1 minute using an ultrasonic disperser. Thereafter, 25 mL of the electrolyte solution was added, and the mixture was further dispersed for 1 minute using the 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 volume average particle size D V asked for. The CV value (%) was calculated according to the following formula: CV value (%) = (standard deviation of particle size distribution) / volume average particle size D V ) x 100

[0138] [Breaking elongation of polyurethane resin] A polyurethane resin particle dispersion adjusted to a solids concentration of 25% by mass was placed in a polypropylene tray (300 mm long, 200 mm wide, 40 mm deep) so that the dry film thickness was 15 μm. A polyurethane resin film was then formed by drying at room temperature. The film was then dried at 110°C for 1 hour to remove moisture, and five strips (10 mm x 70 mm) were cut from the film for measurement. The breaking elongation of each sample was measured using a tensile tester "TENSILON UTM Model III" (manufactured by A&D Co., Ltd.). Measurements were performed at 20°C, with a measurement length of 40 mm and a pulling speed of 4 mm / min. The average breaking elongation of the five samples was taken as the breaking elongation of the polyurethane resin.

[0139] [Glass transition temperature of polyurethane resin] The glass transition temperature of the polyurethane resin was measured using a differential scanning calorimeter "Q100" (manufactured by TA Instruments Japan Co., Ltd.). 0.02 g of the film from which moisture had been removed for the above-mentioned breaking elongation measurement was weighed into an aluminum pan, heated to 150°C, and cooled from 150°C to -20°C at a rate of 10°C / min. The sample was then heated at a rate of 5°C / min, and the calorific value was measured. If a peak was observed, the peak temperature was recorded; if no peak was observed but a step was, the glass transition temperature was recorded as the temperature at the intersection of the tangent line showing the maximum slope of the curve at the step and an extension of the baseline on the low-temperature side of the step.

[0140] [Resin manufacturing] [Production of amorphous resin] Production Example A1 (Production of Resin A-1) A 10 L four-neck flask equipped with a nitrogen inlet tube, a dehydration tube, a stirrer, and a thermocouple was purged with nitrogen, and 4,367 g of propylene oxide (2.2) adduct of bisphenol A, 1,098 g of terephthalic acid, 32 g of tin(II) di(2-ethylhexanoate), and 3.2 g of gallic acid (3,4,5-trihydroxybenzoic acid) were added. The reaction system was heated to 235°C under a nitrogen atmosphere while stirring, and then maintained at 235°C for 5 hours. The pressure in the flask was then reduced and maintained at 8 kPa for 1 hour. The pressure was then returned to atmospheric pressure, cooled to 160°C, and a mixture of 1,070 g of styrene, 267 g of stearyl methacrylate, 144 g of acrylic acid, and 160 g of dibutyl peroxide was added dropwise to the reaction system over 3 hours while maintaining the temperature at 160°C. The reaction system was then maintained at 160°C for 30 minutes, then heated to 200°C. The pressure in the flask was then reduced to 8 kPa and maintained at this temperature for 1 hour. The pressure was then returned to atmospheric pressure, cooled to 190°C, and 174 g of fumaric acid, 378 g of sebacic acid, 240 g of trimellitic anhydride, and 3.2 g of 4-tert-butylcatechol were added. The temperature was then raised to 210°C at a rate of 10°C / hr, and the reaction was continued at 4 kPa until the softening point shown in Table 1 was reached, yielding Resin A-1 (composite resin). The physical properties are shown in Table 1.

[0141] Production Example A2 (Production of Resin A-2) The raw material monomers for polyester resin, excluding trimellitic anhydride, shown in Table 1 were placed in a 10 L stainless steel kettle equipped with a nitrogen inlet tube, a dehydration tube, a stirrer, and a thermocouple. The mixture was reacted at 230°C for 8 hours under a nitrogen atmosphere, and then under reduced pressure of 1.3 to 2.0 kPa for 4 hours. After adding trimellitic anhydride, the mixture was reacted at 180°C until the softening point shown in Table 1 was reached, yielding Resin A-2 (polyester resin). The physical properties are shown in Table 1.

[0142] Manufacturing Example B1 (Manufacturing of Resin B-1) Resin B-1 (polyester resin) was obtained in the same manner as in Production Example A2, except that the raw material monomers for the polyester resin shown in Table 1 were used. Table 1 shows the physical property values. Although Resin B-1 is amorphous Resin A, it is referred to as "Resin B-1" for convenience because it is used to form the shell of the toner particles.

[0143] Manufacturing Example D1 (Manufacturing of Resin D-1) A 10 L four-neck flask equipped with a nitrogen inlet tube, a dehydration tube, a stirrer, and a thermocouple was purged with nitrogen, and 3450 g of a propylene oxide (2.2) adduct of bisphenol A, 655 g of terephthalic acid, 24 g of tin(II) di(2-ethylhexanoate), and 2.4 g of gallic acid (3,4,5-trihydroxybenzoic acid) were added. Under a nitrogen atmosphere, the reaction system was heated to 235°C while stirring and maintained at 235°C for 5 hours. The pressure inside the flask was then reduced and maintained at 8 kPa for 1 hour. After returning to atmospheric pressure, the flask was cooled to 160°C, and a mixture of 2133 g of styrene, 533 g of stearyl methacrylate, 114 g of acrylic acid, and 320 g of dibutyl peroxide was added dropwise over 3 hours while maintaining the temperature at 160°C. The reaction system was then maintained at 160°C for 30 minutes, then heated to 200°C, and the pressure inside the flask was further reduced to 8 kPa and maintained at 8 kPa for 1 hour. After returning to atmospheric pressure, the system was cooled to 190°C, 582 g of succinic acid was added, and the temperature was raised to 210°C at a rate of 10°C / hr. The reaction was then continued at 4 kPa until the softening point shown in Table 1 was reached, yielding Resin D-1 (composite resin). The physical properties are shown in Table 1. Although Resin D-1 is the amorphous resin A, it is referred to as "Resin D-1" for convenience because it is used to produce a release agent particle dispersion liquid.

[0144] [Table 1]

[0145] Manufacturing Example A3 (Manufacturing of Resin A-3) A 5 L four-neck flask equipped with a thermometer, stainless steel stirrer, flow condenser, dropping funnel, and nitrogen inlet tube was charged with 2 L of xylene. 880 g of styrene, 220 g of n-butyl acrylate, and 100 g of dibutyl peroxide were added to the dropping funnel. Under a nitrogen atmosphere, the xylene was heated to 135°C with stirring, and the mixture in the dropping funnel was added dropwise over 1 hour. The temperature was then raised to 200°C and held at 200°C for 2 hours. The pressure in the flask was then reduced to 8 kPa and held for 1 hour. Resin A-3 (styrene-acrylic resin) was obtained by removing the xylene. Its physical properties are shown in Table 2.

[0146] [Table 2]

[0147] [Production of crystalline polyester resin] Production Examples C1 to C7, C'11 to C'14 (Production of Resins C-1 to C-7, C'-11 to C'-14) A 10-L four-neck flask equipped with a nitrogen inlet tube, dehydration tube, stirrer, and thermocouple was purged with nitrogen and charged with the raw material monomers for the polyester resins shown in Table 3-1 or Table 3-2. The reaction system was heated to 135°C while stirring, held at 135°C for 3 hours, and then heated from 135°C to 200°C over 10 hours. 10 g of tin(II) di(2-ethylhexanoate) was then added to the reaction system, and the system was held at 200°C for another 1 hour. The pressure inside the flask was then reduced, and the reaction was continued under a reduced pressure of 8 kPa until the softening points shown in Table 3-1 or Table 3-2 were reached, yielding Resins C-1 to C-7 and C'-11 to C'-14. Physical properties are shown in Table 3-1 or Table 3-2.

[0148] [Table 3-1]

[0149] [Table 3-2]

[0150] [Production of resin particle dispersion] Production Example X1 (Production of Resin Particle Dispersion X-1) 500 g of Resin A-1 and 500 g of methyl ethyl ketone were placed in a 3 L vessel equipped with a stirrer, reflux condenser, dropping funnel, thermometer, and nitrogen inlet tube, and the resin was 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 relative to the acid value of the resin was 60 mol%, and the mixture was stirred for 30 minutes. Next, while maintaining the temperature at 73°C, 1000 g of deionized water was added over 60 minutes while stirring at 200 r / 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 a resin dispersion. Thereafter, while continuing to stir, the dispersion was cooled to 30°C, and deionized water was added to adjust the solids concentration to 25% by mass, thereby obtaining Resin Particle Dispersion X-1. Physical properties are shown in Table 4.

[0151] Production Examples X2, Y1 to Y7, Y'11 to Y'14, Z1, and S1 (Production of Resin Particle Dispersions X-2, Y-1 to Y-7, Y'-11 to Y'-14, Z-1, and S-1) Resin particle dispersions X-2, Y-1 to Y-7, Y'-11 to Y'-14, Z-1, and S-1 were obtained in the same manner as in Production Example X1, except that the resin was changed to the resin shown in Table 4. The physical property values ​​are shown in Table 4.

[0152] Production Example X3 (Production of Resin Particle Dispersion X-3) A 3-L vessel equipped with a stirrer, reflux condenser, dropping funnel, thermometer, and nitrogen inlet tube was charged with 400 g of Resin A-3, 100 g of Resin C-1, 500 g of ethyl acetate, and 100 g of 15% by weight sodium dodecylbenzenesulfonate aqueous solution "Neopelex G-15" (Kao Corporation, anionic surfactant), and dissolved at 70°C for 2 hours. The resulting solution was added with 1400 g of deionized water at 70°C and dispersed for 30 minutes using an ultrasonic homogenizer "UP-400S" (Hielscher GmbH) at 350 W. The ethyl acetate was then removed under reduced pressure while maintaining the temperature at 70°C. Deionized water was added to adjust the solids concentration to 25% by weight, yielding Resin Particle Dispersion X-3. Physical properties are shown in Table 4.

[0153] [Table 4]

[0154] Production Examples U1 to U8 (Production of Polyurethane Resin Particle Dispersions U-1 to U-8) Deionized water was added to the commercially available polyurethane resin particle dispersions shown in Table 5 so that the solid content concentration was 25% by mass, thereby obtaining polyurethane resin particle dispersions U-1 to U-8.

[0155] [Table 5]

[0156] [Production of Release Agent Particle Dispersion] Production Example W1 (Production of Release Agent Particle Dispersion W-1) 120 g of deionized water, 86 g of resin particle dispersion S-1, and 40 g of paraffin wax "HNP-9" (manufactured by Nippon Seiro Co., Ltd., melting point 75°C) were added to a 1 L beaker, 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 further 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 the obtained dispersion to adjust the solid concentration to 20% by mass, thereby obtaining release agent particle dispersion W-1. The volume median particle diameter D of the release agent particles 50 The particle size was 0.47 μm and the CV value was 27%.

[0157] Production Example W2 (Production of Release Agent Particle Dispersion W-2) Release agent particle dispersion W-2 was obtained in the same manner as in Production Example W1, except that the type of release agent was changed to Fischer-Tropsch wax "FNP-00 90" (manufactured by Nippon Seiro Co., Ltd., melting point 90°C). 50 The particle size was 0.45 μm and the CV value was 28%.

[0158] [Preparation of Colorant Particle Dispersion] Production Example E1 (Production of Colorant Particle Dispersion E-1) In a 1 L beaker, 100 g of copper phthalocyanine pigment "ECB-301" (manufactured by Dainichiseika Color & Chemicals Mfg. Co., Ltd.), 35 g of polyoxyethylene (13) distyrenated phenyl ether "EMULGEN A-60" (manufactured by Kao Corporation, nonionic surfactant), and 300 g of deionized water were mixed and dispersed using a homomixer "TKAGI HOMOMIXER 2M-03" (manufactured by Tokushu Kika Kogyo Co., Ltd.) at room temperature (20°C) with a stirring blade rotation speed of 8000 rpm for 1 hour. The mixture was then subjected to 15 passes at a pressure of 150 MPa using a "Microfluidizer M-110EH" (manufactured by Microfluidics), and the mixture was passed through a 200 mesh filter. Deionized water was added to achieve a solids concentration of 20% by mass, yielding colorant particle dispersion E-1. The volume median particle diameter D of the resulting colorant particles was 0.015 μm. 50 The particle size was 0.12 μm and the CV value was 21%.

[0159] [Toner manufacturing] Example 1 (Production of Toner 1) A 3-L four-neck flask equipped with a reflux condenser, a stirrer, and a thermocouple was charged with 340 g of resin particle dispersion X-1, 85 g of resin particle dispersion Y-1, 75 g of polyurethane resin particle dispersion U-1, 49 g of release agent particle dispersion W-1, 49 g of release agent particle dispersion W-2, and 63 g of colorant particle dispersion E-1, and mixed at a temperature of 25° C. Next, while stirring the resulting mixture, a solution prepared by dissolving 40 g of ammonium sulfate in 570 g of deionized water and adding a 4.8 mass % potassium hydroxide aqueous solution to adjust the pH to 8.2 was added dropwise over 10 minutes at 25° C., and the temperature was then raised to 58° C. over 2 hours to measure the volume median particle diameter D of the aggregated particles. 50The temperature was maintained at 58°C until the circularity reached 6.5 μm, thereby obtaining a dispersion of aggregated particles 1. The obtained dispersion of aggregated particles 1 was cooled to 55°C, and while maintaining the temperature at 55°C, 48 g of resin particle dispersion Z-1 was added over 90 minutes to obtain a dispersion of aggregated particles 2 in which resin particles were aggregated to aggregated particles 1. 50 g of a 20 mass% aqueous solution of sodium salt of naphthalenesulfonic acid formalin condensate "Demol MS" (manufactured by Kao Corporation) and 1500 g of deionized water were added to the obtained dispersion of aggregated particles 2. The temperature was then raised to 75°C over 1 hour and maintained at 75°C until the circularity reached 0.970, thereby obtaining a dispersion of fused particles in which aggregated particles 2 were fused. The resulting dispersion of fused particles was cooled to 30°C and filtered under suction to separate the solids, which were then washed with deionized water at 25°C and filtered under suction for 2 hours at 25°C. The solids were then vacuum dried at 33°C for 24 hours using a vacuum constant temperature dryer "DRV622DA" (manufactured by ADVANTEC), yielding toner particles 1 having a core-shell structure. The physical properties of toner particles 1 are shown in Table 6-1. 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 with 100 parts by mass of toner particles 1, stirred, and passed through a 150 mesh sieve to obtain toner 1.

[0160] [Toner Evaluation] The obtained toner 1 was evaluated as follows.

[0161] [Bending resistance of printed matter] Using a commercially available printer "Microline (registered trademark) 5400" (manufactured by Oki Electric Industry Co., Ltd.) on high-quality paper "J paper A4 size" (manufactured by Fujifilm Business Innovation Co., Ltd.), the amount of toner adhered to the paper was 1.49 to 1.51 mg / cm. 2A solid image of the above was printed on an A4 sheet of paper, leaving a 5mm margin from the top, at a length of 50mm, without being fixed. Next, the same printer was prepared with a temperature- and speed-variable fixing unit modified, and the temperature of the fixing unit was set to 140°C, and the toner was fixed at a printing speed of 15 ppm in the portrait direction on A4 paper, to obtain a printout. The prepared print was folded so that the image was on the outside, and a 500 g weight was placed on the folded part and pressed back and forth once. After that, with the folded image unfolded and stretched, a mending tape "Scotch (registered trademark) Mending Tape 810" (manufactured by 3M Japan Ltd., width 18 mm) cut to a length of 50 mm was lightly attached to the folded part, and then a 500 g weight (contact area 1963 mm 2 ) was placed on the sample and pressed back and forth at a speed of 10 mm / s. The tape was then peeled off from the bottom edge at a peel angle of 180° and a speed of 10 mm / s. The bent portion after the tape was peeled off was visually inspected and rated on the following 5-point scale. The higher the score, the better the bending resistance. <Evaluation criteria> 5 points: No peeling at all observed in the folded area. 4 points: Peeling less than 1 mm wide is observed along the bent line. 3 points: Peeling of 1 mm or more but less than 2 mm in width is observed along the fold line. 2 points: Peeling is observed along the fold line, measuring 2 mm or more but less than 4 mm in width. 1 point: Peeling of 4 mm or more in width is observed along the fold line.

[0162] [Document offset resistance of printed matter] The printed matter prepared in the same manner as above was placed on top of a sheet of unprinted high-quality paper, "J paper A4 size," and the result was 80 g / cm 2 The sheet was left to stand for 5 days under a load of 1000 kJ / cm2 at a temperature of 60°C and a relative humidity of 50%, and after 5 days, the sheet was peeled off and visually inspected for the presence or absence of document offset. The obtained results were used to evaluate document offset resistance according to the following criteria. (Evaluation criteria) 5 points: No white spots are visible on the printed surface, and no transfer to the unprinted high-quality paper is visible. 4 points: No white spots are visible on the printed surface, but some transfer to the unprinted high-quality paper is visible. 3 points: A small amount of white space can be seen on the printed matter, but it is still usable. 2 points: White spots are clearly visible on the printed surface. 1 point: A considerable amount of white space can be seen on the printed surface.

[0163] Examples 2 to 15 (Preparation of Toners 2 to 15) Toner particles 2 to 15 and toners 2 to 15 were obtained in the same manner as in Example 1, except that resin particle dispersion X, resin particle dispersion Y, and urethane resin particle dispersion U were changed as shown in Tables 6-1 and 6-2. The physical property values ​​and evaluation results are shown in Tables 6-1 and 6-2.

[0164] Example 16 (Preparation of Toner 16) In Example 1, toner particles 16 and toner 16 were obtained in the same manner as in Example 1, except that the amounts of "resin particle dispersion X-1: 340 g, resin particle dispersion Y-1: 85 g" were changed to "resin particle dispersion X-3: 425 g" and resin particle dispersion Y-1 was not added. The physical property values ​​and evaluation results are shown in Table 6-2.

[0165] Comparative Example 1 (Preparation of Toner c1) Toner particles c1 and toner c1 were obtained in the same manner as in Example 1, except that the amounts of "340 g of resin particle dispersion X-1 and 85 g of resin particle dispersion Y-1" were changed to "400 g of resin particle dispersion X-1 and 100 g of resin particle dispersion Y-1" and no polyurethane resin particle dispersion was added. The physical properties and evaluation results are shown in Table 6-2.

[0166] Comparative Examples 2 to 5 (Preparation of Toners c2 to c5) Toner particles c2 to c5 and toners c2 to c5 were obtained in the same manner as in Example 1, except that resin particle dispersion Y-1 was changed as shown in Table 6-2. Physical property values ​​and evaluation results are shown in Table 6-2.

[0167] [Table 6-1]

[0168] [Table 6-2]

[0169] It can be seen from Tables 6-1 and 6-2 that the printed matter produced using the toner of the present invention is excellent in bending resistance and document offset resistance (Examples 1 to 16). In contrast, the printed matter produced using a toner (Comparative Example 1) that does not contain polyurethane resin U has poor folding resistance. Also, the printed matter produced using a toner (Comparative Examples 2 and 3) that contains a crystalline polyester resin produced without using either ethylene glycol or an α,ω-aliphatic dicarboxylic acid having four carbon atoms, and the printed matter produced using a toner (Comparative Examples 4 and 5) that contains a crystalline polyester resin with an ester group concentration of more than 10.5 mmol / g or less than 6.0 mmol / g have poor document offset resistance.

Claims

1. A toner for developing electrostatic images, comprising toner particles containing an amorphous resin A, a crystalline polyester resin C, and a polyurethane resin U, A toner for developing electrostatic images, wherein the crystalline polyester resin C is a polycondensate of an alcohol component and a carboxylic acid component, satisfies at least one of the following conditions 1 and 2, and has an ester group concentration of 6.0 mmol / g or more and 10.5 mmol / g or less: (Condition 1) The alcohol component contains 80 mol % or more of ethylene glycol (Condition 2) The carboxylic acid component contains 80 mol % or more of an α,ω-aliphatic dicarboxylic acid having 4 carbon atoms.

2. 2. The toner for developing electrostatic images according to claim 1, wherein the polyurethane resin U comprises at least one selected from the group consisting of polyether-based polyurethane resins and polycarbonate-based polyurethane resins.

3. 3. The toner for developing electrostatic images according to claim 1, wherein the crystalline polyester resin C satisfies condition 1.

4. 3. The toner for developing electrostatic images according to claim 1, wherein the proportion of the polyurethane resin U in the toner particles is 10% by mass or more and 50% by mass or less of the total content of the amorphous resin A, the crystalline polyester resin C, and the polyurethane resin U.

5. 3. The toner for developing electrostatic images according to claim 1, wherein the toner particles have a core-shell structure.

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