Electrostatic image developing toner

Abstract

To provide an electrostatic image developing toner capable of producing printed matter with high image density using carbon black.SOLUTION: An electrostatic image developing toner containing a binder resin and a colorant is provided, the binder resin containing an amorphous polyester resin A, or a polycondensate of an alcohol component, a carboxylic acid component, and polyethylene naphthalate, and the colorant containing carbon black with a BET specific surface area of 150 m2 / g or greater.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 meet the demands of higher image quality and higher speeds. Carbon black is widely used as a colorant in black toners, and efforts are being made to improve the image density of printed matter.

[0003] Patent Document 1 discloses a method for producing a toner for developing electrostatic images, which has high coloring power and excellent environmental stability, and includes a step of mixing at least a binder resin, a colorant, and an organic solvent to prepare an oil phase, and a step of mixing the oil phase with an aqueous phase, wherein the colorant has a DBP oil absorption of 25 mL / 100 g or more and 45 mL / 100 g or less and a BET specific surface area of ​​65 m 2 / g or more 120m 2 / g or less carbon black, the binder resin contains an amorphous resin, and the amorphous resin contains at least one of an amorphous polyester resin having an aliphatic hydrocarbon group having 8 or more carbon atoms in the side chain, and an amorphous composite resin containing a polyester segment and an addition polymerization resin segment. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-154020 Summary of the Invention [Problem to be solved by the invention]

[0005] In order to increase the image density of printed matter, it is essential to uniformly disperse the colorant in the toner particles. Carbon black has small primary particles and strong particle cohesion, making it difficult to disperse in the toner particles. Even when printed with a toner obtained by the manufacturing method described in Patent Document 1, the image density of the printed matter was still not sufficient. The present invention relates to a toner for developing electrostatic images that uses carbon black to obtain printed matter having high image density. [Means for solving the problem]

[0006] The present inventors have discovered that by combining an amorphous polyester resin, which is a polycondensate of an alcohol component, a carboxylic acid component, and polyethylene terephthalate, with a colorant containing carbon black having a BET specific surface area equal to or greater than a specific value, and using the combined resin in a toner for developing electrostatic images, it is possible to suppress aggregation of the carbon black in the toner, and to obtain printed matter having high image density using the toner. The present invention relates to the following [1] and [2]. [1] A toner for developing electrostatic images, comprising a binder resin and a colorant, The binder resin contains an amorphous polyester resin A which is a polycondensation product of an alcohol component, a carboxylic acid component, and polyethylene terephthalate, The colorant has a BET specific surface area of ​​150m 2 / g or more of carbon black, Toner for developing electrostatic images. [2] A method for producing the toner for developing electrostatic images according to [1], comprising a step of aggregating resin particles and colorant particles and a step of fusing the resin particles and colorant particles, The resin particles contain an amorphous polyester resin A which is a polycondensation product of an alcohol component, a carboxylic acid component, and polyethylene terephthalate, The colorant particles have a BET specific surface area of ​​150m 2 / g or more of carbon black, A method for producing a toner for developing electrostatic images. [Effects of the Invention]

[0007] According to the present invention, there is provided a toner for developing electrostatic images that uses carbon black and can give printed matter having high image density. DETAILED DESCRIPTION OF THE INVENTION

[0008] [Electrostatic image developing toner] The toner for developing electrostatic images of the present invention (hereinafter also simply referred to as "toner") contains at least a binder resin and a colorant. The binder resin contains an amorphous polyester resin A (hereinafter simply referred to as "resin A") which is a polycondensation product of an alcohol component, a carboxylic acid component, and polyethylene terephthalate (PET). 2 / g or more of carbon black. Due to the above-mentioned characteristics, the toner of the present invention can be used to obtain printed matter having high image density. Examples of recording media for the toner of the present invention include paper and film. Although toner particles containing at least a binder resin and a colorant (hereinafter simply referred to as "toner particles") can be used as they are as the toner of the present invention, it is preferable to use toner particles in which a fluidizing agent or the like is added as an external additive to the surface of the toner particles.

[0009] The reason why a printed matter having a high image density can be obtained by using the toner of the present invention is not clear, but is thought to be as follows. Carbon black with a high BET specific surface area is useful because its small primary particles have high coloring power and can potentially produce printed materials with high image density. However, a high BET specific surface area also increases the number of functional groups (e.g., carboxyl and hydroxyl groups) present per mass unit on the particle surface. Therefore, carbon black with a high BET specific surface area is difficult to disperse in a binder resin and is prone to aggregation. When a toner is produced using a binder resin through kneading using a pulverization method or a fusion process using a chemical method, if the raw material mixture is heated above the glass transition temperature of the amorphous resin and maintained in a low viscosity state, carbon black with a high BET specific surface area will aggregate due to the effects of hydrogen bonding, etc. The toner of the present invention contains an amorphous polyester resin A obtained using polyethylene terephthalate (PET). In the production of resin A, a polycondensation reaction between an alcohol component, a carboxylic acid component, and PET occurs, during which the PET undergoes depolymerization and is incorporated into the polyester resin chain via a transesterification reaction. However, the PET is not incorporated in a completely randomized manner; rather, units known as PET segments exist in the resulting resin. Because these PET segments have a high concentration of ester groups, they readily interact with functional groups on the carbon black surface through hydrogen bonding and other processes. This interaction inhibits aggregation of carbon black with a high BET specific surface area (small primary particle size) in the raw material mixture, resulting in a toner in which the carbon black is uniformly dispersed throughout the toner particles. This results in a toner with excellent coloring power, which is believed to improve the image density of printed materials.

[0010] 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.

[0011] [Toner particles] In the present invention, the toner particles contain a binder resin and a colorant.

[0012] <Binder resin> (Amorphous polyester resin A) In the present invention, the binder resin contains an amorphous polyester resin A (hereinafter also simply referred to as "resin A") which is a polycondensation product of an alcohol component, a carboxylic acid component, and polyethylene terephthalate.

[0013] Examples of the alcohol component include aliphatic diols, alicyclic diols, alkylene oxide adducts of aromatic diols, and trihydric or higher polyhydric alcohols. Among these, from the viewpoint of obtaining printed matter with high image density, at least one selected from aliphatic diols and alkylene oxide adducts of aromatic diols is preferred, and aliphatic diols are more preferred.

[0014] The aliphatic diol preferably has 2 or more carbon atoms and preferably 16 or less, more preferably 12 or less, even more preferably 8 or less, and still more preferably 5 or less. 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, neopentyl glycol (2,2-dimethyl-1,3-propanediol), 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, and 1,12-dodecanediol. Ethylene glycol, 1,2-propanediol, 2,3-butanediol, and neopentyl glycol are preferred, and 1,2-propanediol and neopentyl glycol are more preferred.

[0015] 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).

[0016] The amount of structural units derived from aliphatic diols in the structural units derived from the alcohol component of Resin A is preferably 40 mol% or more, more preferably 60 mol% or more, even more preferably 80 mol% or more, even more preferably 90 mol% or more, and is 100 mol% or less, preferably 100 mol%.

[0017] The amount of PET-derived ethylene glycol structural units in the aliphatic diol-derived structural units is preferably 10 mol% or more, more preferably 20 mol% or more, and even more preferably 25 mol% or more, and is 100 mol% or less, preferably 90 mol% or less, and more preferably 80 mol% or less.

[0018] Examples of alkylene oxide adducts of aromatic diols include those represented by formula (I): [ka] (wherein OR and RO are oxyalkylene groups, each R is independently an ethylene or propylene group, x and y are positive numbers indicating 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). Examples of the alkylene oxide adduct of bisphenol A represented by formula (I) include a propylene oxide adduct of 2,2-bis(4-hydroxyphenyl)propane, and an ethylene oxide adduct of 2,2-bis(4-hydroxyphenyl)propane. When the alcohol component contains an alkylene oxide adduct of bisphenol A, the amount of structural units derived from the alkylene oxide adduct of bisphenol A in the structural units derived from the alcohol component of resin A is preferably 20 mol% or more, more preferably 30 mol% or more, even more preferably 40 mol% or more, and is preferably 80 mol% or less, more preferably 70 mol% or less, even more preferably 60 mol% or less.

[0019] Examples of trihydric or higher polyhydric alcohols include glycerin, pentaerythritol, trimethylolpropane, and sorbitol. The alcohol component may be used alone or in combination of two or more.

[0020] Examples of the carboxylic acid component of Resin A include aromatic dicarboxylic acids, aliphatic dicarboxylic acids, alicyclic dicarboxylic acids, and trivalent or higher polycarboxylic acids.

[0021] Examples of aromatic dicarboxylic acids include terephthalic acid, phthalic acid, and isophthalic acid. Examples of the aliphatic dicarboxylic acid include oxalic acid, malonic acid, fumaric acid, maleic acid, citraconic acid, itaconic acid, glutaconic acid, succinic acid, adipic acid, sebacic acid, and azelaic acid. An example of the alicyclic dicarboxylic acid is cyclohexanedicarboxylic acid. Among these, it is preferable to contain an aromatic dicarboxylic acid, and it is more preferable to contain terephthalic acid. The amount of structural units derived from aromatic dicarboxylic acids in the structural units derived from the carboxylic acid component of Resin A is preferably 70 mol% or more, more preferably 80 mol% or more, even more preferably 90 mol% or more, and is 100 mol% or less, preferably 100 mol%.

[0022] The amount of terephthalic acid constituent units derived from PET is preferably 10 mol% or more, more preferably 15 mol% or more, and even more preferably 20 mol% or more, and is 100 mol% or less, preferably 90 mol% or less, and even more preferably 85 mol% or less, of the constituent units derived from aromatic dicarboxylic acids.

[0023] Examples of trivalent or higher polyvalent carboxylic acids include 1,2,4-benzenetricarboxylic acid (trimellitic acid), 2,5,7-naphthalenetricarboxylic acid, pyromellitic acid, etc. Among these, trimellitic acid is preferred.

[0024] PET is produced by the polycondensation reaction of an alcohol component and a carboxylic acid component, and / or by the depolymerization of a portion of PET. Ethylene glycol and terephthalic acid are then used as raw material monomers in the polycondensation reaction and incorporated into the polyester resin. PET is an equimolar polycondensation product of ethylene glycol and terephthalic acid, and the amounts of the alcohol component-derived structural units and carboxylic acid component-derived structural units mentioned above include the PET-derived ethylene glycol structural units and terephthalic acid structural units, respectively. PET can be produced by conventional methods through the polycondensation of ethylene glycol with terephthalic acid, dimethyl terephthalate, or the like. The PET can be new virgin PET or recycled PET. Recycled PET is obtained by collecting used PET, washing it as needed, separating it from other materials, and then pulverizing it. The pulverized material is then depolymerized to break it down into monomer units, which are then used as raw materials for resynthesis.

[0025] From the viewpoint of obtaining printed matter with high image density, the intrinsic viscosity (hereinafter also referred to as "IV value") of PET is preferably 0.40 or more, more preferably 0.50 or more, even more preferably 0.55 or more, and preferably 0.85 or less, more preferably 0.80 or less, even more preferably 0.75 or less, even more preferably 0.70 or less. The IV value is an index of molecular weight. The IV value of PET can be adjusted by the polycondensation time, etc. The IV value can be measured, for example, by dissolving a sample in a mixed solvent of phenol / tetrachloroethane = 60 / 40 (mass ratio) at a concentration of 0.4 g / dL, measuring with an Ubbelohde viscometer, and calculating according to the following formula.

[0026]

number

[0027] Commercially available PET products include, for example, "RAMAPET L1" (manufactured by Indorama Ventures, IV value: 0.60), "RAMAPET BF3067" (manufactured by Indorama Ventures, IV value: 0.65), "RAMAPET N2G" (manufactured by Indorama Ventures, IV value: 0.75), "TRN-NTJ" (manufactured by Teijin Limited, IV value: 0.53), "TRN-RTJC" (manufactured by Teijin Limited, IV value: 0.64), and "UK-31" (manufactured by Utsumi Recycle Systems Co., Ltd., IV value: 0.67).

[0028] In Resin A, the molar equivalent ratio (COOH groups / OH groups) of the carboxyl groups (COOH groups) of the carboxylic acid component to the hydroxyl groups (OH groups) of the alcohol component 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. The "molar equivalent ratio (COOH groups / OH groups)" is calculated assuming that the alcohol component contains the same mole of ethylene glycol as the PET-derived ethylene glycol constituent unit, and that the carboxylic acid component contains the same mole of terephthalic acid as the PET-derived terephthalic acid constituent unit.

[0029] The PET content is preferably 3 mol% or more, more preferably 7 mol% or more, even more preferably 15 mol% or more, and is preferably 85 mol% or less, more preferably 75 mol% or less, even more preferably 70 mol% or less, from the viewpoint of obtaining printed matter with high image density, out of a total of 100 mol% of the alcohol component, carboxylic acid component, and PET that are the raw materials of Resin A. Since PET is a polycondensation product of ethylene glycol, terephthalic acid, dimethyl terephthalate, etc., the terephthalic acid-ethylene glycol unit (Mw: 192) is considered to be 1 mol. Therefore, moles of PET = moles of ethylene glycol = moles of terephthalic acid.

[0030] <Method for producing amorphous polyester resin A> Resin A can be produced by polycondensing raw materials containing an alcohol component, a carboxylic acid component, and PET. The polycondensation of the alcohol component, the carboxylic acid component, and the PET 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 to 10 parts by mass relative to 100 parts by mass of the total amount of the alcohol component, carboxylic acid component, and PET, which are the raw materials for Resin A. 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, carboxylic acid component, and PET, which are the raw materials for Resin A. 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 to 1 part by mass per 100 parts by mass of the total amount of the alcohol component, carboxylic acid component, and PET that are the raw materials of Resin A.

[0031] <Physical properties of 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.

[0032] The acid value of Resin A is preferably 1 mgKOH / g or more, more preferably 3 mgKOH / g or more, even more preferably 5 mgKOH / g or more, and preferably 30 mgKOH / g or less, more preferably 25 mgKOH / g or less, even more preferably 20 mgKOH / g or less.

[0033] The softening point, glass transition temperature, and acid value of Resin A can be appropriately adjusted 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, 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 the softening point, glass transition temperature and acid value of the resulting mixture are within the above ranges.

[0034] (Crystalline polyester resin C) From the viewpoint of obtaining a printed matter with high image density, the binder resin may contain crystalline polyester resin C (hereinafter also simply referred to as "resin C"), and preferably contains resin C.

[0035] The crystalline polyester resin C is a polycondensation product of an alcohol component and a carboxylic acid component. The alcohol component is preferably an α,ω-aliphatic diol. The α,ω-aliphatic diol preferably has 2 or more carbon atoms, and preferably 16 or less, more preferably 12 or less, and even more preferably 8 or less. Examples of α,ω-aliphatic diols include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, and 1,14-tetradecanediol. Among these, ethylene glycol, 1,6-hexanediol, 1,10-decanediol, and 1,12-dodecanediol are preferred, and ethylene glycol and 1,6-hexanediol are more preferred.

[0036] The amount of α,ω-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%.

[0037] The alcohol component may contain other alcohol components different from the α,ω-aliphatic diols, such as 1,2-propanediol, neopentyl glycol, and other aliphatic diols other than the α,ω-aliphatic diols; 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. The alcohol component may be used alone or in combination of two or more.

[0038] The carboxylic acid component is preferably an aliphatic dicarboxylic acid, more preferably a straight-chain aliphatic dicarboxylic acid. The aliphatic dicarboxylic acid preferably has 4 or more carbon atoms, more preferably 8 or more carbon atoms, and even more preferably 10 or more carbon atoms, and preferably has 14 or less carbon atoms, more preferably 12 or less carbon atoms. Examples of the aliphatic dicarboxylic acid include fumaric acid, sebacic acid, dodecanedioic acid, and tetradecanedioic acid. Among these, sebacic acid is preferred.

[0039] The amount of aliphatic dicarboxylic acid in the carboxylic acid component is preferably 70 mol% or more, more preferably 75 mol% or more, even more preferably 80 mol% or more, still more preferably 85 mol% or more, and is 100 mol% or less, preferably 95 mol% or less.

[0040] From the viewpoint of obtaining a printed matter with high image density, the carboxylic acid component preferably contains a monocarboxylic acid. From the same viewpoint, the number of carbon atoms in the monocarboxylic acid is preferably 6 or more, more preferably 8 or more, even more preferably 12 or more, even more preferably 16 or more, and is preferably 24 or less, more preferably 22 or less, even more preferably 20 or less. Examples of monocarboxylic acids include caprylic acid, pelargonic acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, and lignoceric acid. Among these, preferred are caprylic acid, lauric acid, stearic acid, and behenic acid, 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.

[0041] 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. One or more carboxylic acid components may be used.

[0042] 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.

[0043] The resin C can be produced by the same method as that for the resin A, for example.

[0044] <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 110°C or lower, and even more preferably 90°C or lower.

[0045] 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 130°C or lower, more preferably 110°C or lower, and even more preferably 90°C or lower.

[0046] The acid value of Resin C is preferably 3 mgKOH / g or more, more preferably 5 mgKOH / g or more, and preferably 20 mgKOH / g or less, more preferably 15 mgKOH / g or less, and even more preferably 10 mgKOH / g or less.

[0047] The softening point, melting point, and acid value of Resin C can be appropriately adjusted by adjusting the types and amounts of raw material monomers, as well as production conditions such as reaction temperature, reaction time, and cooling rate. The softening point, melting point, and acid value are determined by the methods described in the Examples. When two or more types of Resin C are used in combination, it is preferable that the softening point, melting point, and acid value of the mixture thereof are each within the above-mentioned ranges.

[0048] From the viewpoint of obtaining printed matter with high image density, the content of the binder resin in the toner particles is preferably 70% by mass or more, more preferably 75% by mass or more, and even more preferably 80% by mass or more, and is preferably less than 98% by mass, and more preferably 95% by mass or less.

[0049] From the viewpoint of obtaining a printed matter with high image density, the content of resin A in the binder resin is preferably 65% ​​by mass or more, more preferably 70% by mass or more, and even more preferably 75% by mass or more, and is 100% by mass or less, preferably 95% by mass or less.

[0050] When the binder resin contains resin C, the content of resin C in the binder resin is preferably 1% by mass or more, more preferably 5% by mass or more, even more preferably 7% by mass or more, from the viewpoint of obtaining a printed matter with high image density, and is preferably 45% by mass or less, more preferably 40% by mass or less, even more preferably 35% by mass or less.

[0051] When the binder resin contains resin C, the mass ratio of resin C to resin A in the toner particles [resin C / resin A] is, from the viewpoint of the thermal responsiveness of the toner, preferably 1 / 99 or more, more preferably 5 / 95 or more, even more preferably 7 / 93 or more, even more preferably 12 / 88 or more, and is preferably 45 / 55 or less, more preferably 35 / 65 or less, even more preferably 30 / 70 or less, even more preferably 25 / 75 or less.

[0052] <Coloring agent> In the present invention, the colorant has a BET specific surface area of ​​150 m 2 / g or more of carbon black (hereinafter, sometimes simply referred to as "carbon black" or "pigment").

[0053] Examples of carbon black include furnace black, thermal lamp black, acetylene black, and channel black. Among these, furnace black is preferred from the viewpoint of coloring power. From the viewpoint of obtaining printed matter with high image density, the pH value of the carbon black is preferably 5 or more, more preferably 6 or more, even more preferably 7 or more, and is preferably 10 or less, more preferably 9 or less, even more preferably 8.5 or less. Specifically, the pH value of carbon black can be measured by the following procedure. (1) 6 g of carbon black, 79 mL of distilled water with a pH of 7, and 1 g of ethanol are placed in a container and mixed. (2) Boil this for 15 minutes, then cool to room temperature for 30 minutes. (3) The supernatant is removed by decantation to obtain a slurry with a solid content of 30 to 35% by mass. (4) Insert a pH electrode into the slurry and measure the pH. The pH value of this slurry is the pH value of the carbon black. An example of a pH meter is the "Seven2Go S2" (manufactured by METTLER TOLEDO). From the viewpoint of toner charging properties, the dibutyl phthalate (DBP) oil absorption of the carbon black is preferably 30 ml / 100 g or more, more preferably 60 ml / 100 g or more, even more preferably 100 ml / 100 g or more, and is preferably 160 ml / 100 g or less, more preferably 140 ml / 100 g or less, even more preferably 125 ml / 100 g or less. The DBP oil absorption of carbon black is measured in accordance with "Determination of oil absorption" of ISO4656 (JIS K6217-4:2008). The BET specific surface area of ​​the carbon black is preferably 180 m from the viewpoint of obtaining a toner for developing electrostatic images that can produce printed matter with higher image density and has excellent environmental stability. 2 / g or more, more preferably 200m 2 / g or more, more preferably 205m 2 / g or more, more preferably 210m 2 / g or more, and preferably 290m 2 / g or less, more preferably 280m 2 / g or less, more preferably 270m 2 / g or less, more preferably 260m 2 / g or less. The BET specific surface area of ​​carbon black can be measured in accordance with JIS K 6217-2:2017 by the method described in the examples. Some carbon blacks are approved by the FDA (Food and Drug Administration) as food contact substances, and it is preferable to use such carbon blacks when applying the toner of the present invention to printed materials that may come into contact with food, such as packaging paper. That is, in accordance with FDA approval standards, the amount of polycyclic aromatic hydrocarbons (PAHs) contained in the carbon black is preferably 10 ppb or less by mass.

[0054] Commercially available carbon black includes, for example, "Printex F80" (manufactured by Orion Engineered Carbon Co., Ltd., pH 8.1, DBP oil absorption 105 ml / 100 g, BET specific surface area 225 m 2 / g), "Black Pearls 4750" (manufactured by Ciyabot Corporation, pH 7.9, DBP oil absorption 117 ml / 100 g, BET specific surface area 240 m 2 / g), "Monarch 4750" (manufactured by Cabot Corporation, pH 7.9, DBP oil absorption 122 ml / 100 g, BET specific surface area 258 m 2 / g), and "Monarch 880" (manufactured by Cabot Corporation, pH 7.4, DBP oil absorption 105 ml / 100 g, BET specific surface area 258 m 2 / g) is an example.

[0055] From the viewpoint of obtaining printed matter with high image density, the content of carbon black in the toner particles is preferably 2% by mass or more, more preferably 3% by mass or more, even more preferably 4% by mass or more, and is preferably 20% by mass or less, more preferably 15% by mass or less, even more preferably 10% by mass or less. Furthermore, the content of carbon black in the toner particles is preferably 1 part by mass or more, more preferably 3 parts by mass or more, and even more preferably 5 parts by mass or more, relative to 100 parts by mass of the binder resin, from the viewpoint of obtaining printed matter with high image density, and is preferably 20 parts by mass or less, more preferably 15 parts by mass or less, and even more preferably 10 parts by mass or less, from the viewpoint of environmental stability.

[0056] The toner particles may contain, as a colorant, in addition to the carbon black having the above-mentioned specific BET specific surface area, other colorants within a range that does not impair the effects of the present invention. However, the content of the other colorants is preferably 20% by mass or less of the total colorants, more preferably 10% by mass or less, even more preferably 5% by mass or less, even more preferably 3% by mass or less, and even more preferably no other colorants are contained.

[0057] <Release agent> The toner particles preferably contain a release agent. Examples of release agents include polypropylene wax, polyethylene wax, ethylene-propylene copolymer wax; hydrocarbon waxes such as microcrystalline wax, paraffin wax, and Fischer-Tropsch wax, or oxides thereof; ester waxes such as carnauba wax, montan wax, or deacidified waxes thereof, and fatty acid ester wax; fatty acid amides, fatty acids, higher alcohols, and fatty acid metal salts. These may be used alone or in combination.

[0058] 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, even more preferably 120°C or lower, and even more preferably 100°C or lower. The content of the release agent in the toner particles is preferably 0.1% by mass or more, more preferably 1% by mass or more, even more preferably 3% by mass or more, and preferably 25% by mass or less, more preferably 15% by mass or less, even more preferably 10% by mass or less.

[0059] 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.

[0060] <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.

[0061] 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 50% or less, more preferably 45% or less, and even more preferably 40% or less, from the viewpoint of obtaining good image quality.

[0062] 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 circularity can be measured by the method described in the Examples.

[0063] [Method for producing toner for developing electrostatic images] The method for producing the toner for developing electrostatic images of the present invention (hereinafter also simply referred to as "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, but the emulsion aggregation method and the melt-kneading method are preferred, and the emulsion aggregation method is more preferred.

[0064] <Emulsification aggregation method> The emulsion aggregation method includes a step of aggregating and fusing resin particles, which contain a resin in the same or different particles, and a colorant containing carbon black in an aqueous medium.

[0065] (Step of aggregating resin particles) In the step of aggregating the resin particles, resin particles containing the same or different resin particles and carbon black are aggregated in an aqueous medium to obtain aggregated particles 1. It is preferable to mix a resin particle dispersion containing resin particles with a colorant particle dispersion containing a colorant (carbon black) and aggregate these particles to obtain aggregated particles 1. It is preferable to further aggregate a release agent in addition to the resin particles and colorant. In addition, in the process of aggregating the resin particles, the aggregated particles 1 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. In the present invention, the aqueous medium is a medium containing water as a main component, and the water content in the aqueous medium is preferably 70% by mass or more, more preferably 80% by mass or more, and even more preferably 90% by mass or more, and 100% by mass or less. The water is preferably deionized water or distilled water. Examples of components other than water that can constitute an 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.

[0066] <Method for producing resin particle dispersion> The resin particles are preferably produced as an aqueous dispersion using an aqueous medium. Dispersion can be carried out using known methods, but is preferably carried out 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 a resin or a molten resin to perform phase inversion emulsification. A preferred method is a method in which an aqueous medium is added to an organic solvent solution of a resin to perform phase inversion emulsification. The organic solvent used for phase inversion emulsification is not particularly limited as long as it dissolves the resin and is water-soluble. For example, methyl ethyl ketone is used for resins C and A. A neutralizing agent may be added to the organic solvent solution. Examples of the neutralizing agent include basic substances. Examples of the basic substance include alkali metal hydroxides such as sodium hydroxide and potassium hydroxide; and nitrogen-containing basic substances such as ammonia, trimethylamine, and diethanolamine. Among these, alkali metal hydroxides such as sodium hydroxide and potassium hydroxide are preferred. The degree of neutralization of the resin constituting the resin particles is preferably 40 mol% or more, more preferably 50 mol% or more, even more preferably 55 mol% or more, and preferably 100 mol% or less, more preferably 95 mol% or less, even more preferably 90 mol% or less. The degree of neutralization of the resin constituting the resin particles can be determined 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

[0067] While stirring the organic solvent solution of the resin or the molten resin, the aqueous medium is gradually added to cause phase inversion. From the viewpoint of improving the dispersion stability of the resin particles, the temperature of the organic solvent solution when the aqueous medium is added is preferably equal to or higher than the glass transition temperature of the resin constituting the resin particles, more preferably equal to or higher than 70°C, and is preferably equal to or lower than 100°C, more preferably equal to or lower than 95°C, and even more preferably equal to or lower than 90°C.

[0068] 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.

[0069] Resin particle volume median diameter D 50 is preferably 0.08 μm or more, more preferably 0.12 μm or more, and is preferably 1 μm or less, more preferably 0.6 μm or less, and even more preferably 0.4 μm or less. The CV value of the resin particles is preferably 10% or more, more preferably 15% 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.

[0070] From the viewpoint of improving toner productivity and the dispersion stability of the aqueous dispersion of resin particles, the solids 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.

[0071] <<Method for producing colorant particle dispersion>> The colorant particle dispersion is preferably obtained by dispersing a colorant containing carbon black and an aqueous medium using a disperser such as a homomixer, a homogenizer, an ultrasonic disperser, etc. From the viewpoint of improving the dispersion stability of the pigment, 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 may also be 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.

[0072] In the colorant particle dispersion, the mass ratio (colorant / dispersant) of the colorant (carbon black) to the dispersant (surfactant or addition polymer) is preferably 50 / 50 or more, more preferably 60 / 40 or more, and even more preferably 65 / 35 or more, from the viewpoints of the chargeability of the toner and the image density of the printed matter, and is preferably 95 / 5 or less, more preferably 90 / 10 or less.

[0073] The content of the colorant in the colorant particle dispersion is preferably 5% by mass or more, more preferably 10% 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, and even more preferably 25% by mass or less. The solid content concentration of the colorant 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 30% by mass or less.

[0074] Volume median particle size D of colorant particles 50 From the viewpoint of improving dispersibility in toner particles, the average particle size is preferably 0.02 μm or more, more preferably 0.04 μm or more, even more preferably 0.06 μm or more, and is preferably 0.25 μm or less, more preferably 0.20 μm or less, even more preferably 0.15 μm or less. From the viewpoint of improving dispersibility in toner particles, the CV value of the colorant particles is preferably 10% or more, more preferably 20% 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.

[0075] <Method for producing release agent particle dispersion> The release agent particle dispersion liquid can be obtained, for example, by dispersing a dispersion liquid of the release agent and resin particles, and optionally an aqueous medium, at a temperature equal to or higher than the melting point of the release agent using a disperser such as a homogenizer, a high-pressure disperser, or an ultrasonic disperser. The heating temperature during dispersion is preferably the melting point of the release agent or higher and 80°C or higher, more preferably 85°C or higher, even more preferably 90°C or higher, and is preferably 100°C or lower, more preferably 98°C or lower, even more preferably 96°C or lower.

[0076] 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 having a polyester resin segment and an addition polymerization resin segment. For details about the release agent particle dispersion and the composite resin, see JP 2021-182045 A. The aforementioned resin A may also be used. The dispersion of resin particles in which the release agent is dispersed is obtained by the aforementioned method for producing a resin particle dispersion.

[0077] Volume median particle size D of release agent particles 50From the viewpoint of obtaining uniform aggregated particles 1 by aggregation, the average particle size is preferably 0.05 μm or more, more preferably 0.2 μm or more, even more preferably 0.3 μm or more, and is preferably 1 μm or less, more preferably 0.8 μm or less, even more preferably 0.6 μm or less. The CV value of the release agent particles is preferably 10% or more, more preferably 20% or more, and is preferably 40% or less, more preferably 35% or less. Volume median particle size D of release agent particles 50 The CV value is measured by the method described in the Examples.

[0078] -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 0.03 parts by mass or more, more preferably 0.06 parts by mass or more, even more preferably 0.1 parts by mass or more, and preferably 10 parts by mass or less, more preferably 5 parts by mass or less, even more preferably 3 parts by mass or less, per 100 parts by mass of resin particles.

[0079] -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.

[0080] For example, 25 to 50 parts by mass of the aggregating agent is added to 100 parts by mass of the resin particles in a mixed dispersion liquid containing resin particles, release agent particles, and colorant particles at a temperature of 0 to 40°C, and the resin particles, release agent particles, and colorant particles are aggregated in an aqueous medium to obtain aggregated particles 1. Furthermore, from the viewpoint of promoting aggregation, it is preferable to increase the temperature of the dispersion liquid after adding the aggregating agent.

[0081] 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. Note that, when the toner manufacturing method includes a step of aggregating shell resin particles (described later), the step of aggregating shell resin particles may be carried out when aggregated particles 1 have grown to an appropriate particle size, without stopping the aggregation.

[0082] -Aggregation stopper- The aggregation terminator is preferably a surfactant, more preferably an anionic surfactant, such as alkylbenzenesulfonate, alkyl sulfate, alkyl ether sulfate, polyoxyalkylene alkyl ether sulfate, arylsulfonate, or arylsulfonic acid formalin condensate. The amount of the aggregation terminator added is preferably 0.5 parts by mass or more, more preferably 1 part 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, and even more preferably 5 parts by mass or less, from the viewpoint of reducing residue in the toner.

[0083] Volume median particle size D of aggregated particles 1 50is 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. Volume median particle size D of aggregated particles 1 50 is measured by the method described in the Examples.

[0084] In the present invention, after the step of aggregating the resin particles and before the step of fusing, a step of adhering shell resin particles containing an amorphous resin to the obtained aggregated particles 1 and aggregating them to obtain aggregated particles 2 may be included. By including the step of aggregating the shell resin particles, toner particles having a core-shell structure can be obtained. The shell resin particles are preferably made of an amorphous resin, more preferably an amorphous polyester resin, and the above-mentioned resin A may be used. The shell resin particle dispersion liquid can be obtained by the above-mentioned method for producing a resin particle dispersion liquid. Furthermore, 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 the above-mentioned aggregation terminator is preferred. 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 25 / 75 or less, more preferably 20 / 80 or less, even more preferably 15 / 85 or less.

[0085] (Fusing 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 polyester resins contained in the aggregated particles. From the viewpoint of improving toner productivity, the holding (heating) temperature when fusing the aggregated particles is preferably equal to or higher than the glass transition temperature of the resin having the highest glass transition temperature among the amorphous polyester resins, more preferably at least 2°C higher, and even more preferably at least 5°C higher, and is preferably not higher than 30°C higher, more preferably not higher than 25°C higher, and even more preferably not higher than 20°C higher than the glass transition temperature of the resin having the highest glass transition temperature among the amorphous polyester resins. In this case, it is preferable to maintain the temperature at the above temperature until the desired circularity is achieved.

[0086] 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.

[0087] 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.

[0088] (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 drying methods include vacuum constant temperature drying, vibration fluidized bed drying, spray drying, freeze drying, and flash jet drying.

[0089] <Melt kneading method> In the present invention, the melt-kneading method involves, for example, uniformly mixing a binder resin, a colorant, and, if necessary, additives such as 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 obtain toner particles.

[0090] <External additives> As described above, it is preferable to use toner particles whose surfaces have been treated with an external additive added thereto as the toner of the present invention. 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.

[0091] 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]

[0092] 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.

[0093] [Measurement method] [Acid value of resin] The acid value of the resin was measured according to the neutralization titration method described in JIS K 0070:1992, except that the measurement solvent was chloroform.

[0094] [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 then cooled 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 endothermic peak with the largest peak area was taken as the maximum endothermic peak temperature (2). For crystalline resins, this peak temperature was taken as the melting point. For amorphous resins, if a peak was observed, the peak temperature was used; if no peak was observed but a step was observed, the glass transition temperature was taken 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.

[0095] [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 cooled to 0°C at a rate of 10°C / min. The sample was then heated at a rate of 10°C / min, the calorific value was measured, and the maximum endothermic peak temperature was taken as the melting point.

[0096] [Volume median particle diameter D of resin particles, release agent particles, and colorant 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 into the 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 and volume average particle size D V The CV value (particle size distribution) was calculated according to the following formula. CV value (%) = (standard deviation of particle size distribution) / volume average particle size D V ) x 100

[0097] [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 min / fluctuation range 0.05%). The solid content concentration was calculated according to the following formula. Solid content concentration (mass%) = 100-moisture (mass%)

[0098] [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, and the volume median particle size D is calculated from the particle size distribution. 50 asked for.

[0099] [Circularity of Fused Particles and Toner 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

[0100] [Volume median particle size D of toner particles 50 〕 The measuring instrument, aperture diameter, analysis software, and electrolyte are all set to 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 to obtain a dispersion with a concentration of 5% by mass. Dispersion conditions: 10 mg of a measurement sample of 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 asked for.

[0101] [BET specific surface area] The BET specific surface area of ​​carbon black was measured in accordance with JIS K6217-2:2017 "Determination of specific surface area." The measurement device used was a multi-sample high-performance specific surface area / pore distribution analyzer "3FLEX" (Shimadzu Corporation), and 1.0 g of sample was measured using the volumetric method for detection and the multipoint method for measurement.

[0102] [Production of amorphous polyester resin] Production Example A1 (Production of Amorphous Polyester Resin A-1) The alcohol component, carboxylic acid component, PET, esterification catalyst, and esterification co-catalyst shown in Table 1 were placed in a 10-liter four-neck flask equipped with a nitrogen inlet tube, a stirrer, a dehydration tube equipped with a condenser, and a thermocouple, and the temperature was raised to 235°C under a nitrogen atmosphere, followed by polycondensation at 235°C for 6 hours. The temperature was then lowered to 210°C, and the reaction was continued under a reduced pressure of 10 kPa until the softening point shown in Table 1 was reached, yielding amorphous polyester resin A-1. The physical properties are shown in Table 1.

[0103] Production Examples A2 to A7 (Production of Amorphous Polyester Resins A-2 to A-7) The alcohol component, carboxylic acid component, PET, esterification catalyst, and esterification promoter shown in Table 1 were placed in a 10-liter four-neck flask equipped with a nitrogen inlet tube, a stirrer, a dehydration tube equipped with a fractionating column through which hot water at 98°C was passed, and a thermocouple. After holding at 180°C for 1 hour under a nitrogen atmosphere, the mixture was heated from 180°C to 235°C at a rate of 10°C / h and polycondensed at 235°C for 5 hours. The mixture was then cooled to 210°C and reacted under a reduced pressure of 10 kPa until the softening point shown in Table 1 was reached, yielding amorphous polyester resins A-2 to A-7. Physical properties are shown in Table 1.

[0104] Manufacturing Example A51 (Amorphous Polyester Resin A-51) The alcohol component, carboxylic acid component, esterification catalyst, and cocatalyst shown in Table 1 were placed in a 10-liter four-neck flask equipped with a nitrogen inlet tube, a stirrer, a dehydration tube equipped with a condenser, and a thermocouple, and the temperature was raised to 235°C under a nitrogen atmosphere, followed by polycondensation at 235°C for 6 hours. The temperature was then lowered to 210°C, and the reaction was continued under a reduced pressure of 10 kPa until the softening point shown in Table 1 was reached, yielding amorphous polyester resin A-51. The physical properties are shown in Table 1.

[0105] Production Example A52 (Production of amorphous polyester resin A-52) The alcohol component, carboxylic acid component, esterification catalyst, and esterification co-catalyst shown in Table 1 were placed in a 10-liter four-neck flask equipped with a nitrogen inlet tube, a dehydration tube fitted with a fractionating column through which hot water at 98°C was passed, a stirrer, and a thermocouple. The mixture was maintained at 180°C for 1 hour under a nitrogen atmosphere, then heated from 180°C to 235°C at a rate of 10°C / h, and polycondensed at 235°C for 5 hours. The temperature was then lowered to 210°C, and the reaction was continued under a reduced pressure of 10 kPa until the softening point shown in Table 1 was reached, yielding amorphous polyester resin A-52. The physical properties are shown in Table 1.

[0106] [Table 1]

[0107] Production Example C1 (Production of Crystalline Polyester Resin C-1) The alcohol component and carboxylic acid component shown in Table 2 were placed in a 10-liter four-neck flask equipped with a thermometer, a stainless steel stirring rod, a dehydration tube equipped with a downflow condenser, and a nitrogen inlet tube, and the temperature was raised to 200°C over 8 hours in a nitrogen atmosphere in a mantle heater. Then, an esterification catalyst shown in Table 2 was added, and the reaction was carried out at 8 kPa until the softening point shown in Table 2 was reached, yielding crystalline polyester resin C-1. The physical properties are shown in Table 2.

[0108] Production Examples C2 and C3 (Production of Crystalline Polyester Resins C-2 and C-3) Crystalline polyester resins C-2 and C-3 were obtained in the same manner as in Production Example C1, except that the alcohol component, carboxylic acid component, and esterification catalyst shown in Table 2 were used in the amounts shown in Table 2. Physical property values ​​are shown in Table 2.

[0109] [Table 2]

[0110] 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 in the flask was further reduced 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 increased to 210°C at 10°C / hr. The reaction was then continued at 4 kPa until the desired softening point was reached, yielding Resin D-1. Resin D-1 had a softening point of 91°C, a glass transition temperature of 42°C, a crystallinity index of 1.8, and an acid value of 24.

[0111] [Production of Resin Particle Dispersion] Production Example X1 (Production of Resin Particle Dispersion X-1) 160 g of Resin A-1, 40 g of Resin C-1, and 200 g of methyl ethyl ketone were placed in a 3-liter vessel equipped with a stirrer, reflux condenser, dropping funnel, thermometer, and nitrogen inlet tube, and the resins were dissolved over 2 hours at 73° C. A 5% by mass aqueous solution of sodium hydroxide was added to the resulting solution so that the degree of neutralization 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, 700 g of deionized water was added over 50 minutes while stirring at 200 r / min, resulting in 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 obtain a solids concentration of 20 mass%, thereby obtaining resin particle dispersion X-1. The volume median particle diameter D of the resulting resin particles was 50 and CV values ​​are shown in Table 3.

[0112] Production examples X2~X12, X51, X52 (manufacture of resin particle dispersions X-2~X-12, X-51, X-52) Resin particle dispersions X-2 to X-12, X-51, and X-52 were obtained in the same manner as in Production Example X1, except that the type and amount of resin used were changed as shown in Table 3. The volume median particle diameter D 50 and CV values ​​are shown in Table 3.

[0113] [Table 3]

[0114] Production Example Y1 (Production of Resin Particle Dispersion Y-1) 200 g of Resin D-1 and 200 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 Resin D-1 was 60 mol%, and the mixture was stirred for 30 minutes. Next, while maintaining the temperature at 73°C, 700 g of deionized water was added over 50 minutes while stirring at 280 r / min to induce phase inversion emulsification. While continuing to maintain the temperature at 73°C, methyl ethyl ketone was distilled off under reduced pressure to obtain an aqueous resin dispersion. The aqueous dispersion was then cooled to 30°C while stirring at 280 r / min, and deionized water was added to obtain a solids concentration of 20% by mass to obtain Resin Particle Dispersion Y-1. The volume median particle diameter of the resin particles was 0.09 μm, and the CV value was 23%.

[0115] [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 Y-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 content 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%.

[0116] [Preparation of Colorant Particle Dispersion] Production Example E1 (Production of Colorant Particle Dispersion E-1) Carbon black "Printex F80" (BET specific surface area 225 m) in a 2L container 2 160 g of 15% by mass sodium dodecylbenzenesulfonate aqueous solution (manufactured by Orion Engineered Carbon), 267 g of 15% by mass sodium dodecylbenzenesulfonate aqueous solution "Neopelex G-15" (manufactured by Kao Corporation, anionic surfactant), and 523 g of deionized water were added, and the mixture was stirred at 6400 rpm at 20°C for 1 hour using a mixer "Labo-Lution" (manufactured by Primix Corporation) equipped with a dispersing blade. The mixture was then passed through a 200-mesh filter and subjected to 15 passes at 150 MPa using a homogenizer "Microfluidizer M-110EH" (manufactured by Microfluidics). The mixture was then passed through a 200-mesh filter, and deionized water was added to adjust the solids concentration to 20% by mass, yielding colorant particle dispersion E-1. The volume median particle diameter D of the resulting colorant particles was 1.0 g. 50 and CV values ​​are shown in Table 4.

[0117] Production Examples E2, E3, and E51 (Production of Colorant Particle Dispersions E-2, E-3, and E-51) A colorant particle dispersion was obtained in the same manner as in Production Example E1, except that the colorant used was changed. 50 and CV values ​​are shown in Table 4.

[0118] [Table 4]

[0119] Example 1 (Production of Toner 1) 500 g of resin particle dispersion X-1, 40 g of release agent particle dispersion W-1, 47 g of colorant particle dispersion E-1, and 1.1 g of a 15% by mass aqueous solution of sodium dodecylbenzenesulfonate "Neopelex G-15" (Kao Corporation, anionic surfactant) were placed in a 3 L four-neck flask equipped with a reflux condenser, a stirrer, and a thermocouple, and mixed at 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% by mass aqueous solution of potassium hydroxide to adjust the pH to 8.4 was added dropwise over 10 minutes at 25° C., and the mixture was then heated to 61° C. over 2 hours to obtain the volume median particle diameter D of the aggregated particles. 50 The temperature was maintained at 61°C until the particle size reached 6.3 µm, thereby obtaining a dispersion of aggregated particles 1. To the obtained dispersion of aggregated particles 1, an aqueous solution prepared by mixing 10 g of sodium polyoxyethylene lauryl ether sulfate "EMAL E-27C" (manufactured by Kao Corporation, anionic surfactant, effective concentration 27% by mass), 280 g of deionized water, and 35 g of a 0.1 mol / L aqueous sulfuric acid solution was added. The temperature was then raised to 74°C over 1 hour, and the mixture was maintained at 74°C for 30 minutes. After that, 15 g of a 0.1 mol / L aqueous sulfuric acid solution was added, and the mixture was further maintained at 75°C for 15 minutes. Thereafter, 10 g of a 0.1 mol / L aqueous sulfuric acid solution was added again, and the mixture was maintained at 75°C until the circularity reached 0.970, thereby obtaining a dispersion of fused particles in which aggregated particles 1 were fused. The obtained dispersion of fused particles was cooled to 30° C., and the dispersion was subjected to suction filtration to separate the solid content, which was then washed with deionized water at 25° C. and suction filtration for 2 hours at 25° C. Thereafter, the solid content was vacuum dried at 33° C. for 24 hours using a vacuum constant temperature dryer "DRV622DA" (manufactured by ADVANTEC), to obtain toner particles. 100 parts by mass of toner particles, 2.5 parts by mass of hydrophobic silica "RY50" (manufactured by Nippon Aerosil Co., Ltd., number average particle diameter: 0.04 μm), and 1.0 part by mass of hydrophobic silica "Cabosil (registered trademark) TS720" (manufactured by Cabot Corporation, number average particle diameter: 0.012 μm) were placed in a Henschel mixer, stirred, and passed through a 150 mesh sieve to obtain Toner 1. The volume median particle diameter D of the obtained toner particles was50 The particle diameter was 6.0 μm and the circularity was 0.970. The obtained toner 1 was evaluated as follows. The evaluation results of toner 1 are shown in Table 5.

[0120] [Image density of printed matter] The toner was printed on high-quality paper "J paper A4 size" (manufactured by Fujifilm Business Innovation Co., Ltd.) using a commercially available printer "Microline (registered trademark) 5400" (manufactured by Oki Electric Industry Co., Ltd.) with a toner adhesion amount of 0.30 mg / cm 2 The solid image was output without being fixed. Next, the same printer was prepared with a modified temperature-variable fixing unit, and the temperature of the fixing unit was set to 120°C. The toner was fixed at a speed of 1.7 seconds per sheet of A4 paper in portrait orientation to obtain a printed matter. Thirty sheets of high-quality paper "Excellent White Paper A4 size" (manufactured by Oki Electric Industry Co., Ltd.) were placed under the print, and the reflected image density of the solid image portion of the output print was measured using a colorimeter "SpectroEye" (manufactured by GretagMacbeth, lighting conditions: standard light source D50, observation field of view 2°, density standard DINNB, absolute white standard), and the values ​​measured at 10 arbitrary points on the image were averaged to obtain the image density. The higher the value, the better the image density.

[0121] Examples 2 to 14 and Comparative Examples 1 to 4 (Production of Toners 2 to 14 and 81 to 84) Toners 2 to 14 and 81 to 84 were prepared in the same manner as in Example 1, except that the types of resin particle dispersion and colorant particle dispersion used were changed as shown in Table 5. The evaluation results of toners 2 to 14 and 81 to 84 are shown in Table 5.

[0122] [Table 5]

[0123] Example 15 (Production of Toner 15) 80 parts by weight of Resin A-1, 20 parts by weight of Resin C-1, 7 parts by weight of Carbon Black CB1 (Printex F80, Orion Engineered Carbon), and 5 parts by weight of paraffin wax "HNP-9" (Nippon Seiro Co., Ltd., melting point 75°C) as a release agent were mixed in a Henschel mixer. The resulting mixture was melt-kneaded using a co-rotating twin-screw extruder with a total length of 1560 mm, a screw diameter of 42 mm, and a barrel inner diameter of 43 mm at a screw rotation speed of 200 r / min and a barrel temperature setting of 100°C to obtain a molten kneaded product. The feed rate of the mixture was 20 kg / h, and the average residence time was approximately 18 seconds. The resulting molten kneaded product was cooled, coarsely crushed, crushed in a jet mill, and classified using an airflow classifier (Nippon Pneumatic Mfg. Co., Ltd.) to obtain a volume median particle size D 50 Powder (toner particles) with a particle size of 6.0 μm was obtained. 100 parts by mass of toner particles, 2.5 parts by mass of hydrophobic silica "RY50" (manufactured by Nippon Aerosil Co., Ltd., number average particle size: 0.04 μm), and 1.0 part by mass of hydrophobic silica "Cabosil (registered trademark) TS720" (manufactured by Cabot Corporation, number average particle size: 0.012 μm) were placed in a Henschel mixer, stirred, and passed through a 150-mesh sieve to obtain Toner 15. The evaluation results of Toner 15 are shown in Table 6.

[0124] Example 16 (Production of Toner 16) Toner 16 was produced in the same manner as in Example 15, except that the resin used was changed as shown in Table 6. The evaluation results of Toner 16 are shown in Table 6.

[0125] [Table 6]

[0126] As shown in Tables 5 and 6, amorphous polyester resin A, which is a polycondensation product of an alcohol component, a carboxylic acid component, and polyethylene terephthalate, and a polyester resin having a BET specific surface area of ​​150 m 2 Printed matter produced using the toner of the present invention containing carbon black with a carbon black content of 1 / g or more has excellent image density (Examples 1 to 16). In contrast, the image density of the printed matter produced using the toner containing the amorphous polyester resin that does not contain polyethylene terephthalate as a raw material monomer was inferior (Comparative Examples 1 and 2). 2 / g (138m 2 / g), the prints produced using the toner containing carbon black had poor image density (Comparative Examples 3 and 4).

Claims

1. A toner for developing electrostatic images, comprising a binder resin and a colorant, the binder resin contains an amorphous polyester resin A which is a polycondensation product of an alcohol component, a carboxylic acid component, and polyethylene terephthalate; The colorant has a BET specific surface area of ​​150 m ２ / g or more of carbon black, Toner for developing electrostatic images.

2. 2. The toner for developing electrostatic images according to claim 1, wherein the content of polyethylene terephthalate in the amorphous polyester resin A is 3 mol % or more and 85 mol % or less of the total amount of the alcohol component, the carboxylic acid component, and the polyethylene terephthalate, where terephthalic acid-ethylene glycol units are 1 mol.

3. The colorant has a BET specific surface area of ​​200 m ２ / g or more 260m ２ 3. The toner for developing electrostatic images according to claim 1, which contains carbon black in an amount of 0.1g or less.

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

5. 3. A method for producing the toner for developing electrostatic images according to claim 1, comprising the steps of aggregating and fusing resin particles and colorant particles, the resin particles contain an amorphous polyester resin A which is a polycondensation product of an alcohol component, a carboxylic acid component, and polyethylene terephthalate; The colorant particles have a BET specific surface area of ​​150 m ２ / g or more of carbon black, A method for producing a toner for developing electrostatic images.

Images