Electrostatic image developing toner

Abstract

To provide an electrostatic image developing toner which is superior in terms of low-temperature fixability and hot offset resistance.SOLUTION: An electrostatic image developing toner containing an amorphous polyester resin A and a polyurethane resin U is provided, the amorphous polyester resin A being a polycondensate of an alcohol component containing 50 mol% or more of aliphatic diol and a carboxylic acid component, and the urethane resin U containing at least one selected from the group consisting of a polyether-based polyurethane resin and a polycarbonate-based polyurethane resin.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 recent years, demand for electrophotographic printing has been increasing in the field of flexible packaging printing, such as food packaging, and from the perspective of stricter safety, development is underway for toners that use polyester resins with reduced content of structural units derived from bisphenol A-based components.

[0003] Patent Document 1 discloses a resin particle containing at least a binder resin, with the aim of providing a resin particle that contributes greatly to carbon neutrality and has excellent low-temperature fixing property and filming resistance, wherein the binder resin is composed of an amorphous polyester resin and a crystalline resin, the alcohol monomer of the amorphous polyester resin contains propylene glycol, the proportion of the crystalline resin in a region within 150 nm from the outermost surface of the resin particle is 4% or less with respect to the total amount of the resin particle, and a radioactive carbon isotope is used. 14 Disclosed are resin particles characterized by a C concentration of 5.4 pMC or more, resin particles for toner containing the resin particles, and toner containing the resin particles for toner. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2023-121119 Summary of the Invention [Problem to be solved by the invention]

[0005] Toners using polyester resins that do not contain structural units derived from bisphenol A-based components or that contain only a small amount of such structural units tend to have low elasticity due to the low content of aromatic rings, and are therefore prone to poor hot offset resistance during thermal fixing. While increasing the softening point of the polyester resin that constitutes the toner can be considered to improve hot offset resistance, this raises the problem of impaired low-temperature fixability. Therefore, the present invention relates to a toner for developing electrostatic images that is excellent in low-temperature fixability and hot offset resistance. [Means for solving the problem]

[0006] The present inventors have found that a toner for electrostatic development containing an amorphous polyester resin, which is a polycondensate of an alcohol component containing 50 mol % or more of an aliphatic diol and a carboxylic acid component, and a polyurethane resin containing a structural unit derived from a polyether polyol or a structural unit derived from a polycarbonate polyol, has excellent low-temperature fixing properties and hot offset resistance. The present invention relates to the following [1]. [1] A toner for developing electrostatic images containing an amorphous polyester resin A and a polyurethane resin U, the amorphous polyester resin A is a polycondensate of an alcohol component containing 50 mol% or more of an aliphatic diol and a carboxylic acid component, The toner for developing electrostatic images, wherein the polyurethane resin U comprises at least one selected from the group consisting of polyether-based polyurethane resins and polycarbonate-based polyurethane resins. [Effects of the Invention]

[0007] According to the present invention, there is provided a toner for developing electrostatic images which is excellent in low-temperature fixability and hot 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 contains an amorphous polyester resin A and a polyurethane resin U, wherein the amorphous polyester resin A is a polycondensate of an alcohol component containing 50 mol % or more of an aliphatic diol and a carboxylic acid component, and the polyurethane resin U contains at least one selected from a polyether-based polyurethane resin and a polycarbonate-based polyurethane resin. Although toner particles containing amorphous polyester resin A and polyurethane resin U (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 the toner after adding a fluidizing agent or the like as an external additive to the surface of the toner particles.

[0009] The mechanism by which the toner of the present invention provides excellent low-temperature fixing properties and hot offset resistance is not clear, but is thought to be as follows.

[0010] Adding a highly elastic component to a toner is effective in improving the toner's hot offset resistance, but the highly elastic component can impair the toner's low-temperature fixability. In the present invention, by using a polyurethane resin containing structural units derived from a polyether polyol and / or a polyurethane resin containing structural units derived from a polycarbonate polyol as the highly elastic component in an amorphous polyester resin, which is a polycondensate of an alcohol component containing 50 mol % or more of an aliphatic diol and a carboxylic acid component, not only the toner's hot offset resistance but also its low-temperature fixability is improved. This is presumably because, in the toner, the amorphous polyester resin containing a large amount of structural units derived from an aliphatic diol interacts with the structural units derived from the polyether polyol and / or the structural units derived from the polycarbonate polyol in the polyurethane resin due to their structural similarity, resulting in the polyurethane resin being finely dispersed in the toner, effectively utilizing the elasticity and adhesive properties of the polyurethane resin. The above-mentioned mechanism regarding the effects of the present invention is only a supposition, and the present invention is not limited to this.

[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.

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

[0013] <Amorphous polyester resin A> The amorphous polyester resin A (hereinafter also simply referred to as "resin A") is a polycondensate of an alcohol component containing 50 mol % or more of an aliphatic diol and a carboxylic acid component. Resin A may be, for example, a composite resin containing a polyester resin segment and an addition polymerization resin segment.

[0014] The alcohol component contains 50 mol % or more of an aliphatic diol. The aliphatic diol preferably has 2 or more carbon atoms, more preferably 3 or more carbon atoms, and preferably 16 or less, more preferably 12 or less, even more preferably 8 or less, and even more preferably 5 or less carbon atoms. Examples of 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, 1,14-tetradecanediol, 1,2-propanediol, and neopentyl glycol. Among these, ethylene glycol, neopentyl glycol, and 1,2-propanediol are preferred, and neopentyl glycol is more preferred.

[0015] The amount of the aliphatic diol in the alcohol component is 50 mol % or more, preferably 70 mol % or more, more preferably 85 mol % or more, and even more preferably 95 mol % or more, and 100 mol % or less.

[0016] From the viewpoint of low temperature fixability and hot offset resistance of the toner, the amount of neopentyl glycol in the alcohol component is preferably 50 mol % or more, more preferably 60 mol % or more, and even more preferably 70 mol % or more, and 100 mol % or less.

[0017] The alcohol component may comprise an alkylene oxide adduct of an aromatic diol. The alkylene oxide adduct of an aromatic diol is preferably an alkylene oxide adduct of bisphenol A, more preferably an alkylene oxide adduct of formula (I): [ka] (In the formula, OR 1 and R 2 O is an oxyalkylene group, and R 1 and R 2are 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. When the alcohol component contains an alkylene oxide adduct of an aromatic diol, the content of the alkylene oxide adduct of an aromatic diol in the alcohol component is preferably 20 mol% or more, more preferably 30 mol% or more, and 50 mol% or less, preferably 45 mol% or less.

[0019] The alcohol component may contain other alcohol components other than the alkylene oxide adducts of aliphatic diols and aromatic diols, such as trihydric or higher alcohols such as glycerin, pentaerythritol, and trimethylolpropane.

[0020] Examples of the carboxylic acid component include dicarboxylic acids and trivalent or higher polycarboxylic acids.

[0021] Examples of dicarboxylic acids include aromatic dicarboxylic acids, aliphatic dicarboxylic acids, and alicyclic dicarboxylic acids. Among these, aromatic dicarboxylic acids are preferred.

[0022] Examples of aromatic dicarboxylic acids include phthalic acid, isophthalic acid, and terephthalic acid. Of these, isophthalic acid and terephthalic acid are preferred. The amount of aromatic dicarboxylic acid in the carboxylic acid component is preferably 70 mol% or more, more preferably 80 mol% or more, even more preferably 90 mol% or more, and is preferably 100 mol% or less, preferably 100 mol%.

[0023] 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.

[0024] An example of the alicyclic dicarboxylic acid is cyclohexanedicarboxylic acid.

[0025] The trivalent or higher polyvalent carboxylic acid is preferably a trivalent carboxylic acid, such as trimellitic acid.

[0026] 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.

[0027] (Method for producing amorphous polyester resin A) Resin A is produced by polycondensing an alcohol component containing 50 mol % or more of an aliphatic diol with a carboxylic acid component. In this reaction, if necessary, an esterification catalyst such as tin(II) di(2-ethylhexanoate), dibutyltin oxide, or titanium diisopropylate bistriethanolamine may be used in an amount of 0.01 to 5 parts by mass per 100 parts by mass of the total amount of the alcohol component and the carboxylic acid component; or an esterification promoter such as gallic acid (equivalent to 3,4,5-trihydroxybenzoic acid) may be used in an amount of 0.001 to 0.5 parts by mass per 100 parts by mass of the total amount of the alcohol component and the carboxylic acid component. When a monomer having an unsaturated bond such as fumaric acid is used in polycondensation, a radical polymerization inhibitor may be used, if necessary, in an amount of preferably 0.001 to 0.5 parts by mass per 100 parts by mass of the total amount of the alcohol component and the carboxylic acid component. Examples of the radical polymerization inhibitor include 4-tert-butylcatechol. The reaction temperature is preferably 120°C or higher, more preferably 150°C or higher, even more preferably 170°C or higher, and is preferably 250°C or lower, more preferably 240°C or lower. The reaction may be carried out in an inert gas atmosphere.

[0028] (Physical properties of amorphous polyester resin A) The softening point of Resin A is preferably 70°C or higher, more preferably 80°C or higher, and even more preferably 90°C or higher, from the viewpoint of the storage stability of the toner, and is preferably 140°C or lower, more preferably 130°C or lower, and even more preferably 120°C or lower, from the viewpoint of the low-temperature fixability of the toner.

[0029] The glass transition temperature of Resin A is preferably 30°C or higher, more preferably 40°C or higher, and even more preferably 50°C or higher, from the viewpoint of the storage stability of the toner, and is preferably 80°C or lower, more preferably 75°C or lower, and even more preferably 70°C or lower, from the viewpoint of the low-temperature fixability of the toner.

[0030] The acid value of Resin A is preferably 2 mgKOH / g or more, more preferably 5 mgKOH / g or more, even more preferably 10 mgKOH / g or more, and preferably 40 mgKOH / g or less, more preferably 35 mgKOH / g or less, even more preferably 30 mgKOH / g or less.

[0031] 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. The softening point, glass transition temperature, and acid value of Resin A 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 fall within the above-mentioned ranges.

[0032] (Crystalline polyester resin C) From the viewpoint of low-temperature fixability of the toner, the toner particles preferably contain a crystalline polyester resin C (hereinafter also simply referred to as "resin C"). Resin C is, for example, a polycondensate 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, more preferably 4 or more carbon atoms, and even more preferably 6 or more carbon atoms, and preferably has 16 or less carbon atoms, more preferably 14 or less carbon atoms, and even more preferably 12 or less carbon atoms. 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 is preferred.

[0033] The amount of the 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, even more preferably 95 mol% or more, and is 100 mol% or less, even more preferably 100 mol%.

[0034] 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; aromatic diols such as alkylene oxide adducts of bisphenol A; and trihydric or higher alcohols such as glycerin, pentaerythritol, and trimethylolpropane.

[0035] The carboxylic acid component is preferably an α,ω-aliphatic dicarboxylic acid. The α,ω-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 α,ω-aliphatic dicarboxylic acid include fumaric acid, sebacic acid, dodecanedioic acid, and tetradecanedioic acid. Among these, sebacic acid is preferred.

[0036] The carboxylic acid component may include a monocarboxylic acid having a hydrocarbon group. From the viewpoint of low-temperature fixability and hot offset resistance of the toner, the number of carbon atoms in the hydrocarbon group of the monocarboxylic acid is preferably 9 or more, more preferably 10 or more, even more preferably 13 or more, even more preferably 15 or more, and is preferably 24 or less, more preferably 23 or less, even more preferably 21 or less. Examples of the hydrocarbon group include aliphatic hydrocarbon groups such as alkyl groups, alkynyl groups, and alkenyl groups, preferably alkyl groups and alkenyl groups, and more preferably alkyl groups. The hydrocarbon group may be branched or linear. Examples of monocarboxylic acids having a hydrocarbon group include capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, lignoceric acid, etc. Among these, from the viewpoint of low-temperature fixability and hot offset resistance of the toner, preferred are lauric acid, stearic acid, and behenic acid, and more preferred are stearic acid.

[0037] The carboxylic acid component may contain other carboxylic acid components different from the aliphatic dicarboxylic acid. Examples of other carboxylic acid components include aromatic dicarboxylic acids such as terephthalic acid and isophthalic acid, and trivalent or higher polycarboxylic acids.

[0038] The amount of α,ω-aliphatic dicarboxylic acid in the carboxylic acid component is preferably 75 mol% or more, more preferably 80 mol% or more, even more preferably 85 mol% or more, and is preferably 99 mol% or less, more preferably 95 mol% or less.

[0039] The amount of monocarboxylic acid having a hydrocarbon group in the carboxylic acid component is preferably 1 mol % or more, more preferably 5 mol % or more, and preferably 25 mol % or less, more preferably 20 mol % or less, and even more preferably 15 mol % or less.

[0040] 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.

[0041] The resin C can be produced by the same method as that for the resin A described above, for example.

[0042] (Physical properties of crystalline polyester resin C) The softening point of Resin C is preferably 60°C or higher, more preferably 65°C or higher, and even more preferably 70°C or higher, from the viewpoint of the storage stability of the toner, and is preferably 130°C or lower, more preferably 110°C or lower, and even more preferably 90°C or lower, from the viewpoint of the low-temperature fixability of the toner. The melting point of resin C is preferably 50°C or higher, more preferably 60°C or higher, and even more preferably 70°C or higher, from the viewpoint of the storage stability of the toner, and is preferably 100°C or lower, more preferably 90°C or lower, and even more preferably 80°C or lower, from the viewpoint of the low-temperature fixability of the toner.

[0043] The acid value of Resin C is preferably 2 mgKOH / g or more, more preferably 5 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. The softening point, melting point, and acid value of resin C can be appropriately adjusted by the type and amount of raw material monomers, as well as production conditions such as reaction temperature, reaction time, and cooling rate, and are determined by the method described in the Examples below. When two or more crystalline polyester resins C are used in combination, it is preferable that the softening point, melting point, and acid value of the mixture thereof each fall within the above-mentioned ranges.

[0044] <Polyurethane Resin U> The polyurethane resin U is a polyaddition product of a polyol component and an isocyanate component including a polyisocyanate.

[0045] (Physical properties of polyurethane resin U) From the viewpoint of low-temperature fixability and hot offset resistance of the toner, the breaking elongation of the polyurethane resin U is preferably 400% or more, more preferably 450% 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.

[0046] From the viewpoint of low-temperature fixability and hot offset resistance of the toner, the glass transition temperature of the polyurethane resin U is preferably −30° C. or higher, more preferably −15° 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.

[0047] 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.

[0048] (Polyurethane resin structure) From the viewpoint of low temperature fixability and hot offset resistance of the toner, the polyurethane resin U contains at least one selected from polyether-based polyurethane resins and polycarbonate-based polyurethane resins, and more preferably contains a polyether-based polyurethane resin.

[0049] (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.

[0050] [ka] 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.

[0051] Examples of the polyether polyol represented by general formula (P1) include polyethylene glycol, polypropylene glycol, polybutylene glycol, and polytetramethylene glycol.

[0052] 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.

[0053] <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.

[0054] [ka]

[0055] In general formula (P2), L 2 and L 3 Each independently represents an alkylene group. n2 is the number of repetitions. The alkylene group may be either linear or branched.

[0056] 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.

[0057] (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.

[0058] Either a synthetic product or a commercially available product can be used as the polyurethane resin U. The synthetic product can be obtained by polyaddition of the above-mentioned polyol and a polyisocyanate compound by a conventional method. Examples of commercially available products include 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., NeoRez R600 (polyether-based polyurethane resin, elongation at break 970%, glass transition temperature 10°C) manufactured by Covestro AG, Bontitor HUX-564 (polycarbonate-based polyurethane resin, elongation at break 700%, glass transition temperature 36°C) manufactured by ADEKA Corporation, and Superflex 460 (polycarbonate-based polyurethane resin, elongation at break 750%, glass transition temperature -21°C) manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.

[0059] <Resin and Polyurethane Resin U Content> The content of Resin A in the toner particles is preferably 30% by mass or more, more preferably 40% by mass or more, even more preferably 50% 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, from the viewpoint of the low-temperature fixability and hot offset resistance of the toner.

[0060] When the toner particles contain resin C, the content of resin C in the toner particles is preferably 1% by mass or more, more preferably 4% by mass or more, even more preferably 7% by mass or more, from the viewpoint of the low-temperature fixability and hot offset resistance of the toner, and is preferably 30% by mass or less, more preferably 25% by mass or less, even more preferably 20% by mass or less.

[0061] When the toner particles contain 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 low-temperature fixability and hot offset resistance of the toner, preferably 2 / 98 or more, more preferably 5 / 95 or more, even more preferably 10 / 90 or more, and is preferably 40 / 60 or less, more preferably 30 / 70 or less, even more preferably 20 / 80 or less.

[0062] The total content of the polyether-based polyurethane resin and polycarbonate-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.

[0063] In the toner particles, the mass ratio of polyurethane resin U to resin A (polyurethane resin U / resin A) is preferably 2 / 98 or more, more preferably 5 / 95 or more, even more preferably 10 / 90 or more, from the viewpoint of the low-temperature fixability and hot offset resistance of the toner, and is preferably 40 / 60 or less, more preferably 30 / 70 or less, even more preferably 20 / 80 or less.

[0064] From the viewpoint of low-temperature fixability and hot offset resistance of the toner, the content of the polyurethane resin 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.

[0065] <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.

[0066] <Release agent> The toner particles preferably contain a release agent. Examples of the release agent 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.

[0067] 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 20% by mass or less, and more preferably 15% by mass or less.

[0068] 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.

[0069] <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.

[0070] 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 40% or less, more preferably 40% or less, and even more preferably 35% or less, from the viewpoint of obtaining good image quality.

[0071] 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 and circularity can be measured by the method described in the Examples.

[0072] [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.

[0073] [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.

[0074] <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.

[0075] 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.

[0076] (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.

[0077] 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. A neutralizing agent may be added to the organic solvent solution of the resin. Examples of the neutralizing agent 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 resin constituting 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 90 mol% or less, even more preferably 85 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

[0078] 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.

[0079] 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.

[0080] A known method can also be used to produce a resin particle dispersion of polyurethane resin U. For example, a commercially available resin particle dispersion of polyurethane resin U can be diluted with an aqueous medium as needed to obtain a resin particle dispersion of a desired solid content concentration.

[0081] 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. Volume median particle diameter D of polyurethane resin particles 50 is preferably 0.01 μm or more, more preferably 0.03 μm or more, and is 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 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.

[0082] 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.

[0083] (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.

[0084] 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.

[0085] 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.

[0086] (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. Examples of resins constituting the resin particles in which the release agent is dispersed include polyester resins. The above-mentioned resin A may be used, or a composite resin D having a polyester resin segment and an addition polymerization resin segment may be used. For details about the release agent particle dispersion and composite resin D, see JP 2021-182045 A.

[0087] 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 0.8 μm or less, more preferably 0.6 μm or less, even more preferably 0.4 μm or less. The CV value of the release agent particles is preferably 10% or more, more preferably 15% or more, and is preferably 55% or less, more preferably 50% or less, and even more preferably 45% or less. Volume median particle size D of release agent particles 50 The CV value is measured by the method described in the Examples.

[0088] <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 resin particles, and is preferably 10 parts by mass or less, and more preferably 5 parts by mass or less.

[0089] <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.

[0090] For example, 10 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 and having 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.

[0091] 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.

[0092] 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.

[0093] 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.

[0094] 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.

[0095] 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.

[0096] <Aggregation stopper> The aggregation terminator is preferably a surfactant, more preferably an anionic surfactant. Examples of anionic surfactants include alkylbenzene sulfonates, alkyl sulfates, alkyl ether sulfates, polyoxyalkylene alkyl ether sulfates, aryl sulfonates, and aryl sulfonic 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, from the viewpoint of reducing residue in the toner.

[0097] <Fusion process> In the fusion step, for example, the aggregated particles 1 or 2 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 1°C higher, more preferably at least 2°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 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.

[0098] 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.

[0099] 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.

[0100] <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.

[0101] [Melt-kneading method] In the present invention, the melt-kneading method involves, for example, uniformly mixing resin A, polyurethane resin U, and, if necessary, additives such as resin C, 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 obtain toner particles.

[0102] <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.

[0103] 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]

[0104] 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.

[0105] [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.

[0106] [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)).

[0107] [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.

[0108] [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

[0109] [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%)

[0110] [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.

[0111] [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

[0112] [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

[0113] [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.

[0114] [Glass transition temperature of polyurethane resin] 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 as a sample, 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. When a peak was observed, the temperature of the peak was recorded; when no peak was observed but a step was, the temperature at the intersection of the tangent showing the maximum slope of the curve at the step and an extension of the baseline on the low-temperature side of the step was recorded as the glass transition temperature.

[0115] [Resin manufacturing] [Production of amorphous polyester resin] Production Example A1 (Production of Resin A-1) The raw material monomers for polyester resins other than isophthalic acid and the esterification catalyst shown in Table 1 were placed in a 10-L four-neck flask equipped with a nitrogen inlet, a dehydration tube fitted with a fractionating column through which hot water at 98°C was passed, a stirrer, and a thermocouple. Under a nitrogen atmosphere, the reaction system was maintained at 180°C for 1 hour, then heated from 180°C to 230°C at a rate of 10°C / h, and then maintained at 230°C for 5 hours to allow polycondensation. After cooling to 180°C, isophthalic acid was added to the reaction system, and the temperature was increased from 180°C to 230°C at a rate of 10°C / h. The reaction was continued for 1 hour at 230°C, and then further continued at 230°C and 10 kPa until the softening point shown in Table 1 was reached, yielding Resin A-1. Physical properties are shown in Table 1.

[0116] Production Examples A2 and A3 (Production of Resins A-2 and A-3) Resins A-2 and A-3 were obtained in the same manner as in Production Example A1, except that the raw material monomers for the polyester resins shown in Table 1 were used in the amounts shown in Table 1. Table 1 shows the physical property values.

[0117] Manufacturing Example A4 (Manufacturing of Resin A-4) The raw material monomers, esterification catalyst, and esterification promoter for the polyester resin shown in Table 1 were placed in a 10-L 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 230°C at a rate of 10°C / h, and polycondensed at 230°C for 5 hours. The reaction was further continued at 230°C under a reduced pressure of 10 kPa until the softening point shown in Table 1 was reached, yielding Resin A-4. The physical properties of Resin A-4 are shown in Table 1.

[0118] Manufacturing Example B1 (Manufacturing of Resin B-1) The raw material monomers for polyester resin (excluding fumaric acid) and the esterification catalyst shown in Table 1 were placed in a 10-L four-neck flask equipped with a nitrogen inlet, a dehydration tube fitted with a fractionating column through which hot water at 98°C was passed, a stirrer, and a thermocouple. Under a nitrogen atmosphere, the reaction system was maintained at 180°C for 1 hour, then heated from 180°C to 230°C at a rate of 10°C / h. The system was then maintained at 230°C for 5 hours to allow polycondensation. After cooling to 180°C, 5 g of fumaric acid and a radical polymerization inhibitor were added to the reaction system, which was then heated from 180°C to 210°C at a rate of 10°C / h. The reaction was continued for 1 hour at 210°C, and then further continued at 210°C and 10 kPa until the softening point shown in Table 1 was reached, yielding Resin B-1. Physical properties are shown in Table 1. Although resin B-1 is amorphous polyester resin A, it is a resin for forming a shell, and is therefore referred to as resin "B-1" for convenience.

[0119] [Table 1]

[0120] [Production of crystalline polyester resin] Manufacturing Example C1 (Manufacturing of Resin C-1) The inside of a 10-L four-neck flask equipped with a nitrogen inlet tube, dehydration tube, stirrer, and thermocouple was replaced with nitrogen, and the raw material monomers for the polyester resin shown in Table 2 were added. 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. Then, 10 g of an esterification catalyst was 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 point shown in Table 2 was reached, yielding Resin C-1. The physical properties are shown in Table 2.

[0121] [Table 2]

[0122] [Production of Resin Particle Dispersion] Production Example X1 (Production of Resin Particle Dispersion X-1) 400 g of Resin A-1, 100 g of Resin C-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 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 80 mol %, and the mixture was stirred for 30 minutes. Next, while maintaining the temperature at 73°C, 1500 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 3.

[0123] Production Examples X2 to X4 (Production of Resin Particle Dispersions X-2 to X-4) Resin particle dispersions X-2 to X-4 were obtained in the same manner as in Production Example X1, except that Resin A-1 in Production Example X1 was changed to Resins A-2 to A-4 shown in Table 3. Physical property values ​​are shown in Table 3.

[0124] Production Example Y1 (Production of Resin Particle Dispersion Y-1) 500 g of Resin B-1 and 500 g of tetrahydrofuran were placed in a 3 L vessel equipped with a stirrer, a reflux condenser, a dropping funnel, a thermometer, and a nitrogen inlet tube, and dissolved over 2 hours at 40° C. A 5% by mass aqueous solution of sodium hydroxide was added to the resulting solution so that the degree of neutralization relative to the acid value of Resin B-1 was 60 mol %, and the mixture was stirred for 30 minutes. Next, while maintaining the temperature at 40°C, 1500 g of deionized water was added over 60 minutes while stirring at 200 r / min (peripheral speed 63 m / min) to cause phase inversion emulsification. The resulting emulsion was heated to 65°C, and the tetrahydrofuran was distilled off under reduced pressure to obtain a resin dispersion. The dispersion was then cooled to 30°C while continuing to stir, and deionized water was added to adjust the solids concentration to 25% by mass, yielding resin particle dispersion Y-1. Physical properties are shown in Table 3.

[0125] Production Example V1 (Production of Resin Particle Dispersion V-1) 100 g of Resin A-1 and 100 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. Resin A-1 was dissolved at 80°C for 1 hour. A 5% by weight aqueous solution of sodium hydroxide was added to the resulting solution to achieve a neutralization degree of 75 mol% relative to the acid value of Resin A-1, and the mixture was stirred for 30 minutes. Next, while maintaining the temperature at 80°C, 350 g of deionized water was added over 60 minutes while stirring at 280 r / min (circumferential speed 88 m / min) to induce phase inversion emulsification. While continuing to maintain the temperature at 80°C, the methyl ethyl ketone was distilled off under reduced pressure to obtain a dispersion. The dispersion was then cooled to 30°C while stirring at 280 r / min (circumferential speed 88 m / min), and deionized water was added to obtain a solids concentration of 20% by weight, yielding Resin Particle Dispersion V-1. Physical properties are shown in Table 3.

[0126] [Table 3]

[0127] Production Examples U1 to U6, U11 to U12 (Production of Polyurethane Resin Particle Dispersions U-1 to U-6, U-11 to U-12) Deionized water was added to the commercially available polyurethane resin particle dispersions shown in Table 4 so that the solid content concentration was 25% by mass, thereby obtaining polyurethane resin particle dispersions U-1 to U-6 and U-11 to U-12.

[0128] [Table 4]

[0129] [Production of release agent particle dispersion] Production Example W1 (Production of Release Agent Particle Dispersion W-1) 25 g of deionized water, 100 g of resin particle dispersion V-1, and 50 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). The solid content was adjusted to 40% by mass with deionized water to obtain release agent particle dispersion W-1. The volume median particle diameter D of the release agent particles was 50 The particle size was 0.29 μm and the CV value was 37%.

[0130] Production Example W2 (Production of Release Agent Particle Dispersion W-2) A release agent particle dispersion W-2 was obtained in the same manner as in Production Example W1, except that the type of release agent used was changed to Fischer-Tropsch wax "FNP-0090" (manufactured by Nippon Seiro Co., Ltd., melting point 90°C). 50 The particle size was 0.26 μm and the CV value was 39%.

[0131] [Production of colorant particle dispersion] Production Example Z1 (Production of Colorant Particle Dispersion Z-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. After that, the mixture was subjected to 15 passes at a pressure of 150 MPa using a "Microfluidizer M-110EH" (manufactured by Microfluidics), and then filtered through a 200 mesh filter. Deionized water was added to achieve a solids concentration of 20% by mass, yielding colorant particle dispersion Z-1. The volume median particle diameter D of the colorant particles was 1.0 μm. 50 The particle size was 0.12 μm and the CV value was 21%.

[0132] [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, 60 g of polyurethane resin particle dispersion U-1, 25 g of release agent particle dispersion W-1, 25 g of release agent particle dispersion W-2, 40 g of colorant particle dispersion Z-1, and 100 g of deionized water, and mixed at a temperature of 25° C. Next, while stirring the resulting mixture, a solution prepared by dissolving 29 g of ammonium sulfate in 780 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 30 minutes at 25° C., and the temperature was then raised to 55° C. over 1 hour, and the volume median particle diameter D of the aggregated particles was measured. 50 The temperature was maintained at 55°C until the particle size reached 6.3 µm, thereby obtaining a dispersion of aggregated particles 1. The obtained dispersion of aggregated particles 1 was cooled to 50°C, and while maintaining the temperature at 50°C, 60 g of resin particle dispersion Y-1 was added over 90 minutes, thereby obtaining a dispersion of aggregated particles 2 in which the resin particles in resin particle dispersion Y-1 adhered to and aggregated the aggregated particles 1. To the resulting dispersion of aggregated particles 2, 68 g of a 20 mass % aqueous solution of Demol N (sodium salt of β-naphthalenesulfonic acid formalin condensate, manufactured by Kao Corporation), 670 g of deionized water, and 380 g of a 4.8 mass % aqueous solution of potassium hydroxide were added. The mixture was then heated to 70°C over 1 hour and maintained at 70°C until the circularity reached 0.970, thereby obtaining a dispersion of fused particles in which aggregated particles 2 were fused. The obtained fused particle dispersion liquid was cooled to 30°C, and the solid content was separated by suction filtration, washed with deionized water at 25°C, and then suction filtered 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 1. 100 parts by mass of toner particles 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, stirred, and passed through a 150 mesh sieve to obtain toner 1. The obtained toner 1 was evaluated as follows. The physical property values ​​of toner particles 1 and the evaluation results of toner 1 are shown in Table 5.

[0133] [Toner Evaluation] The obtained toner 1 was evaluated as follows.

[0134] [Low-Temperature Fixability of Toner] 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 0.60±0.01 mg / cm. 2 The solid image was printed without fixing, leaving a 5mm margin from the top edge of an A4 sheet of paper, and a length of 50mm. Next, the same printer was prepared with a modified temperature-variable fixing unit, and the temperature of the fixing unit was set to 80°C. The toner was fixed onto an A4 sheet in portrait orientation at a speed of 1.5 seconds per sheet, resulting in a printed product. In the same manner, the temperature of the fixing device was increased by 5° C. each time, and the toner was fixed to obtain a printed matter. A 50 mm length of Scotch (registered trademark) Mending Tape 810 (manufactured by Sumitomo 3M Limited, width 18 mm) was lightly applied from the top margin of the printed image to the solid image, and then a 500 g weight (contact area 1963 mm) was applied. 2 ) was placed on the print and pressed back and forth at a speed of 10 mm / s. The applied tape was then peeled off from the bottom edge at a peel angle of 180° and a speed of 10 mm / s to obtain a print after tape removal. Thirty sheets of high-quality paper "Excellent White Paper A4 size" (manufactured by Oki Electric Industry Co., Ltd.) were placed under the print before and after tape removal. The reflection image density of the fixed image portion of each print before and after tape removal was measured using a "SpectroEye" colorimeter (manufactured by GretagMacbeth, lighting conditions: standard light source D50, observation field of view 2°, density standard DINNB, absolute white standard). The fixation rate was calculated from each reflection image density according to the following formula: Fixation rate (%) = (reflected image density after tape peeling / reflected image density before tape application) x 100 The lowest temperature at which the fixing rate is 90% or more is defined as the minimum fixing temperature T1. The lower the minimum fixing temperature, the better the low-temperature fixing ability.

[0135] [Toner high-temperature fixability (hot offset resistance)] Using a commercially available printer "Microline (registered trademark) 5400" (Oki Electric Industry Co., Ltd.) on high-quality paper "J paper A4 size" (Fujifilm Business Innovation Co., Ltd.), the amount of toner adhered to the paper was 0.30±0.01 mg / cm. 2 The solid image was printed without fixing, leaving a 5mm margin from the top edge of an A4 sheet of paper, and a length of 50mm. Next, the same printer was prepared with a temperature-adjustable fuser, and the fuser temperature was set to 130°C. The toner was fixed at a speed of 4 seconds per sheet in portrait A4 size, to obtain a print. It was visually confirmed that no cold offset or hot offset occurred at a fuser temperature of 130°C. In the same manner, the temperature of the fixing unit was raised in increments of 5°C from 130°C, the toner was fixed, a print was obtained, and the occurrence of hot offset was visually confirmed. This test was carried out up to the temperature at which hot offset occurred. Cold offset refers to the phenomenon in which toner adheres to the fixing roller when the fixing temperature is low because the toner on the unfixed image does not melt sufficiently or the release properties are poor. On the other hand, hot offset refers to the phenomenon in which toner adheres to the fixing roller when the fixing temperature is high because the viscoelasticity of the toner on the unfixed image decreases or the release properties become poor at high temperatures. The occurrence of cold offset or hot offset can be determined by whether or not toner adheres to the paper again when the fixing roller makes one revolution. In this test, this was determined by whether or not toner adhered to the area 87 mm from the top edge of the solid image. The hot offset occurrence temperature refers to the temperature at which hot offset begins to occur. Here, the maximum temperature T2 at which hot offset does not occur is set to a temperature 5°C lower than the hot offset occurrence temperature. In addition, in the evaluation of the hot offset occurrence temperature, a difference of 5° C. in the evaluation temperature clearly affects the fixability of the toner.

[0136] Examples 2 to 9 (Production of Toners 2 to 9) Toner particles 2 to 9 and toners 2 to 9 were obtained in the same manner as in Example 1, except that the resin particle dispersion and polyurethane resin particle dispersion were changed as shown in Table 5. The physical property values ​​of toner particles 2 to 9 and the evaluation results of toners 2 to 9 are shown in Table 5.

[0137] Comparative Example 1 (Production of Toner c1) Toner particles c1 and toner c1 were obtained in the same manner as in Example 1, except that 400 g of resin particle dispersion X-1 was used and no polyurethane resin particle dispersion was added. The physical property values ​​of toner particles c1 and the evaluation results of toner c1 are shown in Table 5.

[0138] Comparative Examples 2 to 3 (Production of c2 to c3) Toner particles c2 to c3 and toners c2 to c3 were obtained in the same manner as in Example 1, except that the polyurethane resin particle dispersion was changed as shown in Table 5. Table 5 shows the physical property values ​​of toner particles c2 to c3 and the evaluation results of toners c2 to c3.

[0139] [Table 5]

[0140] Table 5 shows that the toner of the present invention is excellent in low-temperature fixing property and hot offset resistance (Examples 1 to 9). In contrast, when polyurethane resin U is not used (Comparative Example 1) or when a polyester polyurethane resin is used instead of polyurethane resin U (Comparative Examples 2 and 3), the hot offset resistance is poor.

Claims

1. A toner for developing electrostatic images, comprising an amorphous polyester resin A and a polyurethane resin U, the amorphous polyester resin A is a polycondensate of an alcohol component containing 50 mol% or more of an aliphatic diol and a carboxylic acid component, The toner for developing electrostatic images, wherein the polyurethane resin U comprises at least one selected from the group consisting of polyether-based polyurethane resins and polycarbonate-based polyurethane resins.

2. 2. The toner for developing electrostatic images according to claim 1, wherein the mass ratio of the polyurethane resin U to the amorphous polyester resin A (polyurethane resin U / amorphous polyester resin A) is 2 / 98 or more and 40 / 60 or less.

3. 3. The toner for developing electrostatic images according to claim 1, wherein the aliphatic diol has 2 or more and 5 or less carbon atoms.

4. 3. The toner for developing electrostatic images according to claim 1, wherein the polyurethane resin U comprises a polyether-based polyurethane resin.

5. 3. The toner for developing electrostatic images according to claim 1, wherein the polyurethane resin U has a breaking elongation of 400% or more and 1500% or less and a glass transition temperature of -30°C or more and 95°C or less.

6. The toner for developing electrostatic images according to claim 1 or 2, further comprising a crystalline polyester resin C.

Images