White toner for electrostatic image development

Abstract

This invention relates to a white toner for electrostatic image development that can form images with excellent fixation properties to resin films, and to a method for manufacturing the white toner for electrostatic image development. [Solution] A white toner for electrostatic image development, comprising a binder resin, polyurethane resin U, and toner particles containing titanium dioxide, wherein the elongation at break of the polyurethane resin U is 200% or more and 1500% or less.

Description

[Technical Field]

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

[0002] There is a growing demand for printing on colored paper and recording media such as resin films, in addition to the traditional printing on white paper. When printing on non-white recording media, white toner is used to represent white and to improve visibility. Titanium dioxide, a highly opaque inorganic pigment, is commonly used as a coloring agent in white toner.

[0003] Patent Document 1 describes a method for producing a white toner by grinding a molten mixture of a coloring agent containing a binder resin and a white pigment, with the aim of providing a method for producing a highly opaque white toner that does not expose the white pigment on the toner surface and has a stable charge amount and a sharp charge distribution even when the toner particles are made small or a large amount of white pigment is used. The method involves grinding a mixture containing a coloring agent and a binder resin (1) in a molten state, then cooling the mixture, and then grinding it, and is characterized in that the coloring agent is a white pigment dispersion produced by dispersing a white pigment in a binder resin (2), then emulsifying the white pigment dispersion in an aqueous medium, and then separating it from the aqueous medium to produce white resin particles. Furthermore, Patent Document 2 describes a white toner for electrostatic latent image development, which aims to provide a white toner in which a colored image with little color difference is formed between the leading and trailing ends in the transport direction of a transparent recording medium. The toner has toner particles containing an amorphous resin binder, a white pigment, and a release agent, and the temperature-viscosity curve measured by a capillary viscometer has a minimum value in the temperature range of 70°C to 95°C. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2003-255606 [Patent Document 2] Japanese Patent Publication No. 2019-113684 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] In resin film packaging materials used for labels and packages, it is necessary to firmly fix images to the printable resin film over a long period of time in order to suppress the peeling of designs and ingredient information. In particular, for white toner, stronger adhesive strength is required to accommodate surface printing applications where white is printed first on the printing medium and then process colors are printed on top. However, the technologies described in Patent Documents 1 and 2 have not adequately considered this aspect. The present invention relates to a white toner for electrostatic image development that can form an image with excellent fixability to a resin film, and to a method for manufacturing the white toner for electrostatic image development. [Means for solving the problem]

[0006] The inventors have found that images obtained using a white toner for electrostatic image development containing a binder resin, a polyurethane resin U having a specific break elongation, and toner particles containing titanium dioxide exhibit excellent fixation to resin films. The present invention relates to the following [1] and [2]. [1] Containing binder resin, polyurethane resin U, and toner particles containing titanium dioxide, A white toner for electrostatic image development, wherein the polyurethane resin U has a breaking elongation of 200% to 1500%. [2] The process includes a step of agglomerating and fusing binder resin particles, polyurethane resin U particles, and titanium oxide particles in an aqueous medium. A method for manufacturing a white toner for electrostatic charge image development, wherein the elongation at break of the polyurethane resin U is 200% or more and 1500% or less.

Effects of the Invention

[0007] According to the present invention, there are provided a white toner for electrostatic charge image development capable of forming an image excellent in fixing property to a resin film, and a method for manufacturing the white toner for electrostatic charge image development.

Modes for Carrying Out the Invention

[0008] [White Toner for Electrostatic Charge Image Development] The white toner for electrostatic charge image development of the present invention (hereinafter, also simply referred to as "toner" or "white toner") includes toner particles containing a binder resin, a polyurethane resin U, and titanium oxide, and the elongation at break of the polyurethane resin U is 200% or more and 1500% or less. In addition, the toner particles (hereinafter, also simply referred to as "toner particles") can be used as they are as the toner of the present invention, but it is preferable to use those obtained by adding a fluidizing agent or the like as an external additive to the surface of the toner particles as the toner.

[0009] The reason why an image excellent in fixing property to a resin film can be formed by the white toner of the present invention is not clear, but it is considered as follows. In the white toner, since titanium oxide used as a colorant is a metal particle, it forms a pseudo-crosslink between the binder resins in the binder resin, and the elasticity of the white toner becomes high. Therefore, internal stress is likely to occur in the printed coating film (image) output by the white toner, and this is considered to be the cause of the progress of image peeling with respect to the resin film over time. The polyurethane resin contained in the white toner of the present invention contains a relatively high-polarity urethane bond, and has an elongation at break of 200% or more and 1500% or less, that is, it has a high elongation and high flexibility. As a result, it exhibits high adhesiveness to the resin film, and while the relatively high-polarity urethane bond relaxes the action (pseudo-crosslinking between binder resins) between titanium oxide and the resin, due to its characteristics of high elongation and high flexibility, it can relax the stress generated in the printed coating film. Therefore, the printed coating film formed using the white toner of the present invention can exhibit high fixing property to the resin film for a long time, that is, it is considered to have excellent fixing property. Examples of the resin film include polyethylene terephthalate (PET) film, polyethylene film, polypropylene film, nylon film, and polyvinyl chloride film.

[0010] The definitions of various terms 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 generate carboxylic acids, and alkyl esters (alkyl groups having 1 to 3 carbon atoms) of each carboxylic acid. Whether the resin is crystalline or amorphous is determined by the crystallinity index. The crystallinity index is defined as the ratio of the softening point of the resin to the maximum peak temperature of endotherm in the measurement method described in the examples below (softening point (°C) / maximum peak temperature of endotherm (°C)). A crystalline resin is one having a crystallinity index of 0.6 or more and 1.4 or less. An amorphous resin is one in which no endothermic peak is observed, or if observed, the crystallinity index is less than 0.6 or more than 1.4. The crystallinity index can be appropriately adjusted according to the type and ratio of the raw material monomers, and production conditions such as reaction temperature, reaction time, and cooling rate. Regarding the hydrocarbon group, the description with “(iso or tertiary)” and “(iso)” in parentheses means both the case where these prefixes are present and the case where they are not present. When these prefixes are not present, it indicates normal. "(Meth)acrylic acid" means at least one selected from acrylic acid and methacrylic acid. "Styrene compounds" refers to unsubstituted or substituted styrene.

[0011] [Toner particles] The toner particles contain a binder resin, polyurethane resin U, and titanium dioxide. The toner particles may contain each component, such as the binder resin, polyurethane resin U, and titanium dioxide, individually or in combination of two or more. Furthermore, the raw materials for each component contained in the toner particles, such as alcohol components and carboxylic acid components, may be used individually or in combination of two or more.

[0012] <Binding resin> In the present invention, the binder resin preferably contains an amorphous resin from the viewpoint of image fixation to the resin film, more preferably contains at least one selected from amorphous polyester resin A and styrene acrylic resin, and more preferably contains amorphous polyester resin A. Furthermore, the binder resin preferably further contains crystalline polyester resin C from the viewpoint of toner fixation at low temperatures. Hereinafter, amorphous polyester resin A may be referred to as "resin A" and crystalline polyester resin C may be referred to as "resin C".

[0013] (Amorphous polyester resin A) Resin A contains a polyester resin segment which is a polycondensate of an alcohol component and a carboxylic acid component. Examples of resin A include polyester resin, and composite resins containing polyester resin segments and addition polymerization resin segments.

[0014] Examples of the alcohol component of resin A include alkylene oxide adducts of aromatic diols, aliphatic diols, alicyclic diols, and polyhydric alcohols of trihydric or higher hydric value. Among these, alkylene oxide adducts of aromatic diols and aliphatic diols are preferred, with alkylene oxide adducts of aromatic diols being more preferred.

[0015] The alkylene oxide adduct of an aromatic diol is preferably an alkylene oxide adduct of bisphenol A, and more preferably of formula (I):

[0016] [ka] (In the formula, OR 1 and R 2 O is an oxyalkylene group, R 1 and R 2 This is an alkylene oxide adduct of 2,2-bis(4-hydroxyphenyl)propane, where each is independently an ethylene group or a propylene group, x and y represent the average number of moles of alkylene oxide added, each being a positive number, and the sum of x and y is 1 or more, preferably 1.5 or more, 16 or less, preferably 8 or less, and more preferably 4 or less.

[0017] Examples of alkylene oxide adducts of bisphenol A represented by formula (I) include propylene oxide adducts of bisphenol A and ethylene oxide adducts of bisphenol A. When the alcohol component contains an alkylene oxide adduct of an aromatic diol, the content of the alkylene oxide adduct of the aromatic diol in the alcohol component is preferably 60 mol% or more, more preferably 80 mol% or more, even more preferably 90 mol% or more, and 100 mol% or less, and preferably 100 mol%.

[0018] Examples of aliphatic diols include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 2,2-dimethyl-1,3-propanediol (neopentyl glycol), 1,6-hexanediol, 1,8-octanediol, and 3-methyl-1,5-pentanediol. Among these, neopentyl glycol is preferred from the viewpoint of image fixation to resin films. When the alcohol component contains an aliphatic diol, the aliphatic diol content in the alcohol component is preferably 60 mol% or more, more preferably 80 mol% or more, even more preferably 90 mol% or more, and 100 mol% or less, and preferably 100 mol%.

[0019] Examples of alicyclic diols include hydrogenated bisphenol A [2,2-bis(4-hydroxycyclohexyl)propane] and alkylene oxide adducts of hydrogenated bisphenol A with 2 to 4 carbon atoms (average number of added moles: 2 to 12).

[0020] Examples of polyhydric alcohols with a valency of 3 or higher include glycerin, pentaerythritol, trimethylolpropane, and sorbitol.

[0021] Examples of carboxylic acid components in resin A include dicarboxylic acids and polycarboxylic acids with a valency of three or more.

[0022] Examples of dicarboxylic acids include aromatic dicarboxylic acids, aliphatic dicarboxylic acids, and alicyclic dicarboxylic acids. Among these, at least one selected from aromatic dicarboxylic acids and aliphatic dicarboxylic acids is preferred.

[0023] Examples of aromatic dicarboxylic acids include phthalic acid, isophthalic acid, and terephthalic acid. Among these, isophthalic acid and terephthalic acid are preferred. The amount of aromatic dicarboxylic acid is preferably 30 mol% or more, more preferably 40 mol% or more, even more preferably 50 mol% or more, and 100 mol% or less, in the carboxylic acid component.

[0024] The number of carbon atoms in the aliphatic dicarboxylic acid is preferably 2 or more, more preferably 3 or more, and preferably 30 or less, more preferably 20 or less. Examples of aliphatic dicarboxylic acids include oxalic acid, malonic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, dodecanediic acid, and succinic acid substituted with hydrocarbon groups. Examples of succinic acid substituted with hydrocarbon groups include dodecyl succinic acid, dodecenyl succinic acid, and octenyl succinic acid. Among these, fumaric acid, sebacic acid, and succinic acid substituted with hydrocarbon groups are preferred from the viewpoint of image fixation to resin films. When the carboxylic acid component includes an aliphatic dicarboxylic acid, the amount of aliphatic dicarboxylic acid in the carboxylic acid component is preferably 1 mol% or more, more preferably 4 mol% or more, even more preferably 7 mol% or more, and preferably 50 mol% or less, more preferably 45 mol% or less, and even more preferably 40 mol% or less.

[0025] Examples of alicyclic dicarboxylic acids include cyclohexanedicarboxylic acid.

[0026] Preferably, the polycarboxylic acid with a valency of 3 or higher is a trivalent carboxylic acid, such as trimellitic acid. When the carboxylic acid component contains a polycarboxylic acid of trivalent or higher, the amount of the polycarboxylic acid of trivalent or higher in the carboxylic acid component is preferably 1 mol% or more, more preferably 4 mol% or more, even more preferably 7 mol% or more, and preferably 25 mol% or less, more preferably 20 mol% or less, and even more preferably 15 mol% or less.

[0027] The equivalent ratio [COOH group / OH group] of the carboxyl group of the carboxylic acid component to the hydroxyl group of the alcohol component is preferably 0.7 or higher, more preferably 0.8 or higher, and preferably 1.3 or lower, more preferably 1.2 or lower.

[0028] When resin A is a composite resin, examples of addition polymerization resin segments include addition polymerization products of raw material monomers containing styrene compounds. Examples of styrene compounds include unsubstituted or substituted styrene. Examples of substituents that can be substituted for styrene include alkyl groups having 1 to 5 carbon atoms, halogen atoms, alkoxy groups having 1 to 5 carbon atoms, sulfonic acid groups, or salts thereof. Examples of styrene-based compounds include styrene, methylstyrene, α-methylstyrene, β-methylstyrene, tert-butylstyrene, chlorostyrene, chloromethylstyrene, methoxystyrene, styrene sulfonic acid, or salts thereof. Among these, styrene is preferred. The content of styrene compounds in the raw material monomers of the addition polymerization resin segment is preferably 50% by mass or more, more preferably 65% ​​by mass or more, even more preferably 75% by mass or more, and 100% by mass or less, preferably 95% by mass or less, more preferably 90% by mass or less, and even more preferably 85% by mass or less.

[0029] Other raw material monomers besides styrene compounds include, for example, (meth)acrylic acid esters such as alkyl (meth)acrylate, benzyl (meth)acrylate, and dimethylaminoethyl (meth)acrylate; olefins such as ethylene, propylene, and butadiene; halovinyls such as vinyl chloride; vinyl esters such as vinyl acetate and vinyl propionate; vinyl ethers such as methyl vinyl ether; vinylidene halides such as vinylidene chloride; and N-vinyl compounds such as N-vinylpyrrolidone. Among these, (meth)acrylic acid esters are preferred, and alkyl (meth)acrylate is more preferred. The number of carbon atoms in the alkyl group of (meth)acrylate is preferably 1 or more, more preferably 4 or more, even more preferably 6 or more, and preferably 24 or less, more preferably 22 or less, and even more preferably 20 or less. Examples of alkyl (meth)acrylates include methyl (meth)acrylate, ethyl (meth)acrylate, isopropyl (meth)acrylate, iso(or tertiary)butyl (meth)acrylate, isoamyl (meth)acrylate, cyclohexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, isooctyl (meth)acrylate, isodecyl (meth)acrylate, isododecyl (meth)acrylate, isopalmityl (meth)acrylate, isostearyl (meth)acrylate, isobehenyl (meth)acrylate, etc. From the viewpoint of image fixation to resin film, 2-ethylhexyl (meth)acrylate or stearyl (meth)acrylate is preferred, more preferably stearyl (meth)acrylate, and even more preferably stearyl methacrylate.

[0030] When the addition polymerization resin segment contains constituent units derived from (meth)acrylic acid ester, the content of (meth)acrylic acid ester in the raw material monomer of the addition polymerization resin segment is preferably 5% by mass or more, more preferably 10% by mass or more, even more preferably 15% by mass or more, and preferably 50% by mass or less, more preferably 35% by mass or less, and even more preferably 25% by mass or less.

[0031] The total amount of styrene compounds and (meth)acrylic acid esters in the raw material monomers of the addition polymerization resin segment is preferably 80% by mass or more, more preferably 90% by mass or more, even more preferably 95% by mass or more, and even more preferably 100% by mass.

[0032] The composite resin preferably has constituent units derived from both reactive monomers that are covalently bonded to a polyester resin segment and an addition polymerization resin segment. "Constituent units derived from both reactive monomers" refers to units formed by the reaction of the functional groups and addition polymerizable groups of both reactive monomers. Examples of addition polymerizable groups include carbon-carbon unsaturated bonds (ethylenically unsaturated bonds). Examples of both reactive monomers include addition polymerizable monomers having at least one functional group selected from hydroxyl groups, carboxyl groups, epoxy groups, primary amino groups, and secondary amino groups within the molecule. Among these, addition polymerizable monomers having at least one functional group selected from hydroxyl groups and carboxyl groups are preferred from the viewpoint of reactivity, and addition polymerizable monomers having carboxyl groups are more preferred. Examples of addition polymerizable monomers having a carboxyl group include acrylic acid, methacrylic acid, fumaric acid, and maleic acid. Among these, acrylic acid and methacrylic acid are preferred from the viewpoint of reactivity in both polycondensation and addition polymerization reactions, with acrylic acid being more preferred. When both reactive monomers are addition polymerizable monomers having a carboxyl group, the amount of constituent units derived from both reactive monomers is preferably 1 mol or more, more preferably 5 mol or more, even more preferably 8 mol or more, and preferably 30 mol or less, more preferably 25 mol or less, and even more preferably 20 mol or less, per 100 mol parts of the alcohol component of the polyester resin segment of the composite resin.

[0033] The polyester resin segment content in the composite resin is preferably 50% by mass or more, more preferably 60% by mass or more, even more preferably 70% by mass or more, and preferably 95% by mass or less, more preferably 90% by mass or less, and even more preferably 85% by mass or less, based on 100% by mass of the total amount of polyester resin segments and addition polymerization resin segments. The constituent units derived from both reactive monomers are polyester resin segments.

[0034] The content of addition polymerization resin segments in the composite resin is preferably 5% by mass or more, more preferably 10% by mass or more, even more preferably 15% by mass or more, and preferably 50% by mass or less, more preferably 40% by mass or less, and even more preferably 30% by mass or less, based on 100% by mass of the total amount of polyester resin segments and addition polymerization resin segments.

[0035] The amount of constituent units derived from both reactive monomers in the composite resin is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, even more preferably 0.8% by mass or more, and preferably 15% by mass or less, more preferably 10% by mass or less, and even more preferably 5% by mass or less, based on 100% by mass of the total amount of the polyester resin segment and the addition polymerization resin segment.

[0036] The total amount of polyester resin segments and addition polymerization resin segments in the composite resin is preferably 80% by mass or more, more preferably 90% by mass or more, even more preferably 95% by mass or more, and 100% by mass or less, and preferably 100% by mass.

[0037] The above amounts are calculated based on the ratio of the raw material monomers for the polyester resin segment, the addition polymerization resin segment, the two reactive monomers, and the radical polymerization initiator. The mass of the polyester resin segment, etc., is based on the mass excluding the mass of water produced by polycondensation. When a radical polymerization initiator is used, the mass of the radical polymerization initiator is included in the calculation of the addition polymerization resin segment.

[0038] (Method for producing amorphous polyester resin A) ≪Method for manufacturing polyester resin≫ Polyester resins can be produced, for example, by polycondensation of raw material monomers containing alcohol and carboxylic acid components. The polycondensation of the alcohol component and the carboxylic acid component can be carried out, for example, in an inert gas atmosphere, at a temperature of approximately 120°C to 250°C, in the presence of an esterification catalyst, esterification co-catalyst, polymerization inhibitor, etc., as needed. Examples of esterification catalysts include tin compounds such as dibutyltin oxide and di(2-ethylhexanoate)tin(II), and titanium compounds such as titanium diisopropoxybis(triethanolamine). Examples of esterification co-catalysts that can be used together with the esterification catalyst include gallic acid (3,4,5-trihydroxybenzoic acid). The amount of esterification catalyst used is preferably 0.01 parts by mass or more and 10 parts by mass or less, based on 100 parts by mass of the total amount of alcohol and carboxylic acid components, which are raw material monomers for the polyester resin. The amount of esterification co-catalyst used is preferably 0.001 parts by mass or more and 1 part by mass or less, per 100 parts by mass of the total amount of the alcohol component and the carboxylic acid component. Examples of polymerization inhibitors include radical polymerization inhibitors such as 4-tert-butylcatechol. When a polymerization inhibitor is used, the amount of polymerization inhibitor used is preferably 0.001 parts by mass or more and 1 part by mass or less per 100 parts by mass of the total amount of the alcohol component and the carboxylic acid component.

[0039] ≪Method for manufacturing composite resins≫ The composite resin may be produced, for example, by a method comprising step A, in which an alcohol component and a carboxylic acid component are polycondensed, and step B, in which raw material monomers and both reactive monomers of an addition polymerization resin segment are addition polymerized. Process A may be performed after process B, or process B may be performed after process A, or process A and process B may be performed simultaneously. In step A, a portion of the carboxylic acid component is subjected to a polycondensation reaction, and then step B is carried out. After that, the remaining carboxylic acid component is added to the polymerization system to further advance the polycondensation reaction in step A and the polycondensation reaction with the reactive groups, such as carboxyl groups, that are present in both reactive monomers or constituent units derived from both reactive monomers.

[0040] In step A, if necessary, the esterification catalyst and esterification co-catalyst described in the above-mentioned method for producing polyester resin may be used in the same amounts for polycondensation. Furthermore, when using monomers having unsaturated bonds, such as fumaric acid, in polycondensation, the polymerization inhibitor described in the above-mentioned method for producing polyester resin may be used in the same amount as necessary. The temperature of the polycondensation reaction is preferably 120°C or higher, more preferably 150°C or higher, even more preferably 180°C or higher, and preferably 250°C or lower, more preferably 240°C or lower. The polycondensation may be carried out in an inert gas atmosphere.

[0041] Examples of radical polymerization initiators for the addition polymerization in step B include peroxides such as dibutyl peroxide, persulfates such as sodium persulfate, and azo compounds such as 2,2'-azobis(2,4-dimethylvaleronitrile). The amount of radical polymerization initiator used is preferably 1 to 20 parts by mass per 100 parts by mass of raw material monomers of the addition polymerization resin segment. The addition polymerization temperature is preferably 110°C or higher, more preferably 130°C or higher, and preferably 240°C or lower, more preferably 230°C or lower, and even more preferably 220°C or lower.

[0042] (Physical properties of amorphous polyester resin A) The softening point of resin A is preferably 70°C or higher, more preferably 85°C or higher, and even more preferably 95°C or higher, from the viewpoint of the heat-resistant storage properties of the toner, and preferably 140°C or lower, more preferably 130°C or lower, and even more preferably 125°C or lower, from the viewpoint of the low-temperature fixing properties of the toner. The glass transition temperature of resin A is preferably 35°C or higher, more preferably 40°C or higher, and even more preferably 45°C or higher, from the viewpoint of the heat-resistant storage properties of the toner, and 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 fixing properties of the toner.

[0043] The acid value of resin A is preferably 5 mg KOH / g or more, more preferably 10 mg KOH / g or more, and more preferably 35 mg KOH / g or less, more preferably 30 mg KOH / g or less, and even more preferably 25 mg KOH / g or less.

[0044] The softening point, glass transition temperature, and acid value of resin A can be appropriately adjusted depending on the type and amount of raw material monomer used, as well as manufacturing conditions such as reaction temperature, reaction time, and cooling rate. These values ​​can be determined by the method described in the examples. Furthermore, when using two or more types of resin A in combination, it is preferable that at least one of them falls within the range of the above physical properties. Moreover, it is even more preferable that the softening point, glass transition temperature, and acid value obtained as a mixture thereof are each within the above range.

[0045] (Styrene acrylic resin) Styrene acrylic resin is an addition polymerization product of a styrene-based compound and alkyl (meth)acrylate. As the styrene-based compound, the styrene-based compound in the addition polymerization resin segment described above can be used, and styrene is preferred.

[0046] The content of styrene-based compounds in the raw material monomers of styrene-acrylic resin is preferably 65% ​​by mass or more, more preferably 70% by mass or more, even more preferably 75% by mass or more, and preferably 95% by mass or less, more preferably 90% by mass or less, and even more preferably 85% by mass or less.

[0047] The number of carbon atoms in the alkyl group of (meth)acrylate is preferably 1 or more, more preferably 3 or more, and preferably 24 or less, more preferably 22 or less, and even more preferably 20 or less. Examples of alkyl (meth)acrylates include methyl (meth)acrylate, ethyl (meth)acrylate, propyl (meth)acrylate, iso(or tertiary)butyl (meth)acrylate, iso(amyl) (meth)acrylate, cyclohexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, iso(octyl) (meth)acrylate, iso(decyl) (meth)acrylate, iso(dodecyl) (meth)acrylate, iso(palmityl) (meth)acrylate, iso(stearyl) (meth)acrylate, and iso(behenyl) (meth)acrylate, with iso(or tertiary)butyl (meth)acrylate being preferred, and n-butyl acrylate being preferred.

[0048] The alkyl (meth)acrylate content in the raw material monomer of the styrene-acrylic resin is preferably 5% by mass or more, more preferably 10% by mass or more, even more preferably 15% by mass or more, and preferably 35% by mass or less, more preferably 30% by mass or less, and even more preferably 25% by mass or less.

[0049] Styrene acrylic resin may contain constituent units derived from raw material monomers other than styrene compounds and alkyl (meth)acrylates. Examples of raw material monomers other than styrene compounds and alkyl (meth)acrylates include (meth)acrylic acid esters such as benzyl (meth)acrylate and dimethylaminoethyl (meth)acrylate; olefins such as ethylene, propylene, and butadiene; halovinyls such as vinyl chloride; vinyl esters such as vinyl acetate and vinyl propionate; vinyl ethers such as methyl vinyl ether; vinylidene halides such as vinylidene chloride; and N-vinyl compounds such as N-vinylpyrrolidone. The polymerization mode of the styrene-acrylic resin may be random, block, or graft.

[0050] (Method of manufacturing styrene acrylic resin) Styrene acrylic resin can be produced by addition polymerization of raw material monomers in the same manner as in step B described above.

[0051] (Physical properties of styrene-acrylic resin) The softening point of the styrene-acrylic resin is preferably 70°C or higher, more preferably 85°C or higher, and even more preferably 95°C or higher, from the viewpoint of the toner's heat resistance stability, and preferably 140°C or lower, more preferably 130°C or lower, and even more preferably 125°C or lower, from the viewpoint of the toner's low-temperature fixability.

[0052] The glass transition temperature of the styrene-acrylic resin is preferably 35°C or higher, more preferably 40°C or higher, and even more preferably 45°C or higher, from the viewpoint of the toner's heat resistance stability, and preferably 80°C or lower, more preferably 70°C or lower, and even more preferably 65°C or lower, from the viewpoint of the toner's low-temperature fixability.

[0053] The softening point and glass transition temperature of styrene-acrylic resin can be appropriately adjusted depending on the type and amount of raw material monomer used, as well as manufacturing conditions such as reaction temperature, reaction time, and cooling rate. These values ​​can be determined by the method described in the examples. Furthermore, when using two or more types of styrene-acrylic resin in combination, it is preferable that the softening point and glass transition temperature obtained from the mixture are within the above ranges.

[0054] (Crystalline polyester resin C) From the viewpoint of the toner's low-temperature fixation properties, it is preferable that the toner particles contain 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. As the alcohol component, α,ω-aliphatic diols are preferred. The number of carbon atoms in the α,ω-aliphatic diol is preferably 2 or more, preferably 16 or less, more preferably 12 or less, even more preferably 8 or less, and even more preferably 4 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 is preferred.

[0055] The amount of α,ω-aliphatic diol 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 100 mol% or less, preferably 100 mol%, in the alcohol component.

[0056] The alcohol component may contain other alcohol components other than α,ω-aliphatic diols. Examples of other alcohol components include aliphatic diols other than α,ω-aliphatic diols such as 1,2-propanediol and neopentyl glycol; aromatic diols such as alkylene oxide adducts of bisphenol A; and trivalent or higher alcohols such as glycerin, pentaerythritol, and trimethylolpropane.

[0057] As the carboxylic acid component, α,ω-aliphatic dicarboxylic acids are preferred. The number of carbon atoms in the α,ω-aliphatic dicarboxylic acid is preferably 4 or more, more preferably 8 or more, even more preferably 10 or more, and preferably 14 or less, more preferably 12 or less. Examples of α,ω-aliphatic dicarboxylic acids include fumaric acid, sebacic acid, dodecanediic acid, and tetradecanediic acid. Among these, sebacic acid is preferred.

[0058] The carboxylic acid component may include a monocarboxylic acid having a hydrocarbon group. 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 preferably 24 or less, more preferably 22 or less, and even more preferably 20 or less. Examples of hydrocarbon groups include aliphatic hydrocarbon groups such as alkyl groups, alkynyl groups, and alkenyl groups, with alkyl groups and alkenyl groups being preferred, and alkyl groups being more preferred. The hydrocarbon group may be branched or linear, with linear being preferred. Examples of monocarboxylic acids having a hydrocarbon group include capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, and lignoceric acid. Among these, lauric acid, stearic acid, and behenic acid are preferred, and stearic acid is more preferred.

[0059] The carboxylic acid component may contain other carboxylic acid components other than aliphatic dicarboxylic acids. Examples of other carboxylic acid components include aromatic dicarboxylic acids such as terephthalic acid and isophthalic acid; and polycarboxylic acids with a valency of three or more.

[0060] The amount of α,ω-aliphatic dicarboxylic acid is preferably 75 mol% or more, more preferably 80 mol% or more, even more preferably 85 mol% or more, and 100 mol% or less of the carboxylic acid component.

[0061] If a monocarboxylic acid having a hydrocarbon group is included, the amount 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, of the carboxylic acid component.

[0062] The equivalent ratio [COOH group / OH group] of the carboxyl group of the carboxylic acid component to the hydroxyl group of the alcohol component is preferably 0.7 or higher, more preferably 0.8 or higher, and preferably 1.3 or lower, more preferably 1.2 or lower.

[0063] A method for manufacturing resin C can be similar to that of resin A mentioned above.

[0064] (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 toner storage stability, and preferably 130°C or lower, more preferably 110°C or lower, and even more preferably 90°C or lower, from the viewpoint of toner low-temperature fixation. The melting 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 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 fixing properties of the toner.

[0065] The acid value of resin C is preferably 2 mg KOH / g or more, more preferably 5 mg KOH / g or more, and more preferably 25 mg KOH / g or less, more preferably 20 mg KOH / g or less, and even more preferably 15 mg KOH / g or less. The softening point, melting point, and acid value of resin C can be appropriately adjusted depending on the type and amount of raw material monomer used, as well as manufacturing conditions such as reaction temperature, reaction time, and cooling rate, and can be determined by the method described in the examples. When two or more types of crystalline polyester resin C are used in combination, it is preferable that the softening point, melting point, and acid value obtained as a mixture thereof are within the aforementioned ranges.

[0066] <Polyurethane resin U> Polyurethane resin U is a polyadduct of a polyol component and an isocyanate component containing polyisocyanate.

[0067] (Physical properties of polyurethane resin U) The elongation at break of the polyurethane resin U is 200% or more, preferably 350% or more, more preferably 500% or more, even more preferably 600% or more, even more preferably 700% or more, and 1500% or less, preferably 1350% or less, and even more preferably 1200% or less, from the viewpoint of image fixation to the resin film.

[0068] The glass transition temperature of the polyurethane resin U is preferably -60°C or higher, more preferably -50°C or higher, and even more preferably -35°C or higher, from the viewpoint of the heat-resistant storage properties of the toner, and preferably 95°C or lower, more preferably 75°C or lower, even more preferably 50°C or lower, and even more preferably 35°C or lower, from the viewpoint of the low-temperature fixing properties of the toner.

[0069] The elongation at break and glass transition temperature of polyurethane resin U can be appropriately adjusted depending on the type and amount of raw material monomer used, as well as manufacturing conditions such as reaction temperature, reaction time, and cooling rate. When two or more types of polyurethane resin U are used in combination, it is preferable that the elongation at break of the mixture is between 200% and 1500%, within the preferred range described above. It is even more preferable that the glass transition temperature of the mixture is within the preferred range described above. The mixture may also be a mixture of a polyurethane resin with an elongation at break of 200% or more and 1500%, and a polyurethane resin with an elongation at break outside the range of 200% or more and 1500%. The elongation at break and glass transition temperature of polyurethane resin U can be determined by the method described in the examples.

[0070] (Structure of polyurethane resin U) From the viewpoint of image fixation to the resin film, the polyurethane resin U preferably contains at least one selected from polyether-based polyurethane resin, polycarbonate-based polyurethane resin, and polyester-based polyurethane resin, more preferably contains at least one selected from polyether-based polyurethane resin and polycarbonate-based polyurethane resin, and even more preferably contains polyether-based polyurethane resin.

[0071] (Polyol component) ≪Polyether Polyol≫ The polyether polyol, which is the polyol component of polyether-based polyurethane resin, can be one which has hydroxyl groups at both ends of the main chain. For example, a compound represented by the following general formula (P1) can be used.

[0072] [ka]

[0073] In general formula (P1), L 1 The symbol indicates an alkylene group, and n1 is the number of repeats. 1 The alkylene groups shown may be the same or different from each other. The alkylene group may be linear or branched, and the number of carbon atoms is preferably 2 or more, more preferably 3 or more, even more preferably 4 or more, and preferably 8 or less, more preferably 7 or less, and even more preferably 6 or less.

[0074] Examples of polyether polyols represented by general formula (P1) include polyethylene glycol, polypropylene glycol, polybutylene glycol, and polytetramethylene glycol.

[0075] Polyether polyols may be either synthetic or commercially available. Synthetic polyols can be obtained, for example, by ring-opening polymerization of cyclic ether compounds using a compound having an active hydrogen atom as a catalyst.

[0076] ≪Polycarbonate Polyol≫ Polycarbonate polyols, which are the polyol components of polycarbonate-based polyurethane resins, can be those having hydroxyl groups at both ends of the main chain. For example, compounds represented by the following general formula (P2) can be used.

[0077] [ka]

[0078] In general formula (P2), L 2 and L 3 Each of these independently represents an alkylene group. n2 is the number of repeats. The alkylene group can be either linear or branched.

[0079] Polycarbonate polyols may be either synthetic or commercially available. Synthetic polyols are obtained by reacting diols with dialkyl carbonates or cyclic carbonates.

[0080] Polyester polyol The polyester polyol, which is the polyol component of the polyester-based polyurethane resin, can be, for example, one that has hydroxyl groups at both ends of the main chain.

[0081] (Isocyanate component) Examples of polyisocyanates include aliphatic diisocyanates, aromatic diisocyanates, and prepolymerized, isocyanurate, urea, and carbodiimide modified forms of these diisocyanates. Examples of aliphatic diisocyanates include alicyclic diisocyanates and linear 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 linear aliphatic diisocyanates include straight-chain aliphatic diisocyanates and branched-chain aliphatic diisocyanates, and more specifically, tetramethylene diisocyanate, hexamethylene diisocyanate, dodecamethylene diisocyanate, and 2,4,4-trimethylhexamethylene diisocyanate. Examples of aromatic diisocyanates include m-phenylenediisocyanate, p-phenylenediisocyanate, 2,4-tollylenediisocyanate, 2,6-tollylenediisocyanate, 1,3-xylylenediisocyanate, 1,4-xylylenediisocyanate, tetramethylxylylenediisocyanate, 1,5-naphthylenediisocyanate, 4,4'-diphenylmethanediisocyanate, 4,4'-dibenzyliisocyanate, tetraalkyldiphenylmethanediisocyanate, and 3,3'-dimethyl-4,4'-biphenylenediisocyanate. Furthermore, the isocyanate component may also include monoisocyanate.

[0082] Polyurethane resin U can be either a synthetic or commercially available product. Synthetic products can be obtained by polyadding the above-mentioned polyol component and isocyanate component by conventional methods. Commercial products include, for example, Takelac W6061 (polyether-based polyurethane resin, elongation at break 1000%, glass transition temperature 25℃) and Takelac W5661 (polyether-based polyurethane resin, elongation at break 600%, glass transition temperature 70℃) from Mitsui Chemicals, Inc., WBR-016U (polyether-based polyurethane resin, elongation at break 760%, glass transition temperature 15℃) from Taisei Fine Chemical Co., Ltd., and NeoRez from Covestró. R600 (polyether polyurethane resin, elongation at break 970%, glass transition temperature 10℃), BASF Elastoran ET370 (polyether polyurethane resin, elongation at break 800%, glass transition temperature -50℃), ADEKA Corporation Bontiter HUX-564 (polycarbonate polyurethane resin, elongation at break 700%, glass transition temperature 36℃), DIC Corporation Hydran WLS-210 (polycarbonate polyurethane resin, elongation at break 480%, glass transition temperature -32℃), DIC Corporation High Examples include Doran GP-300 (polycarbonate-based polyurethane resin, elongation at break 340%, glass transition temperature -33℃), Superflex 460 (polycarbonate-based polyurethane resin, elongation at break 750%, glass transition temperature -21℃) manufactured by Daiichi Kogyo Seiyaku Co., Ltd., Hydran AP-201 (polyester-based polyurethane resin, elongation at break 570%, glass transition temperature 7℃) manufactured by DIC Corporation, and Hydran AP-10 (polyester-based polyurethane resin, elongation at break 300%, glass transition temperature 27℃) manufactured by DIC Corporation.

[0083] <Contents of binding resin and polyurethane resin> The content of the binder resin in the toner particles is preferably 35% by mass or more, more preferably 40% by mass or more, and even more preferably 45% by mass or more, from the viewpoint of image fixation to the resin film, and preferably 95% by mass or less, and more preferably 90% by mass or less, from the viewpoint of image density.

[0084] When the binder resin contains resin A, the content of resin A in the binder resin is preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 75% by mass or more, and 100% by mass or less, from the viewpoint of image fixation to the resin film, and preferably 95% by mass or less, more preferably 90% by mass or less, and even more preferably 85% by mass or less, from the viewpoint of toner low-temperature fixation.

[0085] When the binder resin contains styrene-acrylic resin, the styrene-acrylic resin content in the binder resin is preferably 60% by mass or more, more preferably 70% by mass or more, even more preferably 75% by mass or more, and 100% by mass or less, from the viewpoint of the storage stability of the toner, and preferably 95% by mass or less, more preferably 90% by mass or less, and even more preferably 85% by mass or less, from the viewpoint of the low-temperature fixability of the toner.

[0086] When the binder resin contains resin C, the content of resin C in the binder resin is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 15% by mass or more, from the viewpoint of the toner's low-temperature fixability, and preferably 35% by mass or less, more preferably 30% by mass or less, and even more preferably 25% by mass or less, from the viewpoint of the toner's storage stability.

[0087] When the binder resin contains resin A and resin C, the mass ratio of resin C to resin A in the toner particles [resin C / resin A] is preferably 5 / 95 or more, more preferably 10 / 90 or more, and even more preferably 15 / 85 or more, from the viewpoint of the toner's low-temperature fixability, and from the viewpoint of the toner's storage stability, it is preferably 40 / 60 or less, more preferably 30 / 70 or less, and even more preferably 25 / 75 or less.

[0088] When the binder resin contains styrene-acrylic resin and resin C, the mass ratio of resin C to styrene-acrylic resin in the toner particles [resin C / styrene-acrylic resin] is preferably 5 / 95 or more, more preferably 10 / 90 or more, and even more preferably 15 / 85 or more, from the viewpoint of the toner's low-temperature fixability, and from the viewpoint of the toner's storage stability, it is preferably 40 / 60 or less, more preferably 30 / 70 or less, and even more preferably 25 / 75 or less.

[0089] The total content of polyether-based polyurethane resin, polycarbonate-based polyurethane resin, and polyester-based polyurethane resin in 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 100% by mass or less, and preferably 100% by mass, from the viewpoint of image fixation to the resin film.

[0090] In toner particles, the content of polyurethane resin U relative to 100 parts by mass of binder resin is preferably 3 parts by mass or more, more preferably 7 parts by mass or more, even more preferably 10 parts by mass or more, and preferably 50 parts by mass or less, more preferably 40 parts by mass or less, even more preferably 30 parts by mass or less, and even more preferably 20 parts by mass or less.

[0091] The content of polyurethane resin U in the toner particles is preferably 2% by mass or more, more preferably 5% by mass or more, and preferably 40% by mass or less, more preferably 30% by mass or less, even more preferably 20% by mass or less, and even more preferably 10% by mass or less, from the viewpoint of image fixation to the resin film.

[0092] <Titanium Oxide> As titanium dioxide, rutile-type titanium dioxide or anatase-type titanium dioxide can be used, but from the viewpoint of stability and availability, rutile-type titanium dioxide is preferred. From the viewpoint of obtaining good dispersibility in toner particles, titanium dioxide that has been surface-treated is preferred. The surface treatment of titanium dioxide is not particularly limited, and it may be treated with either organic or inorganic materials. From the viewpoint of avoiding the influence of photocatalysis, titanium dioxide surface-treated with inorganic materials is preferred, titanium dioxide surface-treated with at least one of silica and alumina is more preferred, and titanium dioxide surface-treated with both silica and alumina is even more preferred. Surface-treated titanium dioxide powder can also be fired at a temperature between 800°C and 1,000°C to suppress interparticle sintering and improve the fluidity and dispersibility of the titanium dioxide. The particle shape of titanium dioxide can be granular, needle-shaped, etc., but is not particularly limited.

[0093] The average primary particle size (number-average particle size) of titanium dioxide is preferably 100 nm or more, more preferably 150 nm or more, even more preferably 200 nm or more, and even more preferably 220 nm or more, from the viewpoint of obtaining the desired particle size of the colorant particles and obtaining high whiteness, and from the viewpoint of dispersibility, it is preferably 500 nm or less, more preferably 400 nm or less, even more preferably 350 nm or less, even more preferably 300 nm or less, and even more preferably 280 nm or less. The average primary particle size of titanium dioxide is measured by the method described in the examples. Examples of commercially available titanium dioxide products used in this invention include the following products manufactured by Teika Co., Ltd.: product names JR, JR-300, JR-605, JR-701, and the following products manufactured by Ishihara Sangyo Co., Ltd.: product names Typeque CR-93, CR-90, CR-80, etc.

[0094] The titanium dioxide content in the toner particles is preferably 10% by mass or more, more preferably 20% by mass or more, even more preferably 25% by mass or more, and preferably 60% by mass or less, more preferably 50% by mass or less, and even more preferably 40% by mass or less, from the viewpoint of further improving dispersibility in the toner particles and from the viewpoint of image density of the printed coating film (image). The toner of the present invention may contain a colorant other than titanium oxide within a range that does not impair the effects of the present invention. The content of the colorant other than titanium oxide in the toner particles is preferably 1% by mass or less, more preferably 0.5% by mass or less, and 0% by mass or more, and preferably 0% by mass.

[0095] <Release agent> The toner particles preferably contain a release agent. Examples of the release agent include hydrocarbon waxes such as polypropylene wax, polyethylene wax, ethylene-propylene copolymer wax, microcrystalline wax, paraffin wax, Fischer-Tropsch wax, or their oxides; ester waxes such as carnauba wax, montan wax, or their deacidified waxes, fatty acid ester waxes; fatty acid amides, fatty acids, higher alcohols, and fatty acid metal salts.

[0096] The melting point of the release agent is preferably 60°C or higher, more preferably 70°C or higher, and preferably 160°C or lower, more preferably 140°C or lower, still more preferably 120°C or lower, still more preferably 100°C or lower, and still more preferably 80°C or lower. The content of the release agent in the toner particles is preferably 1% by mass or more, more preferably 3% by mass or more, and preferably 15% by mass or less, more preferably 10% by mass or less.

[0097] In addition, the toner particles may contain additives such as charge control agents, magnetic powders, fluidity improvers, conductivity adjusters, reinforcing fillers such as fibrous substances, antioxidants, anti-aging agents, and cleaning property improvers.

[0098] 〔Physical properties of toner particles〕 The volume median particle diameter D of the toner particles 50 is preferably 2 μm or more, more preferably 3 μm or more, still more preferably 4 μm or more, and preferably 10 μm or less, more preferably 8 μm or less, still more preferably 7 μm or less from the viewpoint of obtaining a printed coating film (image) with good image quality.

[0099] The circularity of the toner particles is preferably 0.945 or higher from the viewpoint of improving image quality, and preferably 0.990 or lower, more preferably 0.985 or lower, and even more preferably 0.980 or lower from the viewpoint of toner cleanability. Volume-intermediate particle size D of toner particles 50 The roundness can be measured by the method described in the examples.

[0100] [Manufacturing method for white toner for electrostatic image development] The method for producing the white toner for electrostatic image development of the present invention (hereinafter also referred to as the "toner production method") may be any known method such as the melt-kneading method, the emulsion-phase inversion method, the suspension polymerization method, or the emulsion-coagulation method, with the emulsion-coagulation method and the melt-kneading method being preferred, and the emulsion-coagulation method being more preferred.

[0101] [Emulsification aggregation method] The emulsification and coagulation method includes steps of coagulating resin particles and titanium dioxide particles in an aqueous medium and fusing them together. In the description of the emulsification and coagulation method, when simply referred to as "resin particles," it means binding resin particles and / or polyurethane resin particles.

[0102] <Process for agglomerating resin particles> In the process of agglomerating resin particles, resin particles and titanium dioxide particles are agglomerated in an aqueous medium to obtain agglomerated particles 1. It is preferable to further agglomerate a release agent in addition to the resin particles, and it is preferable to mix the resin particle dispersion, the coloring agent particle dispersion (titanium dioxide particle dispersion), and the release agent particle dispersion, and agglomerate these particles to obtain agglomerated particles 1. Here, the term "resin" in "resin particles" is used to include resin A, styrene-acrylic resin, resin C, and polyurethane resin U. Furthermore, the resin particles may contain the resin in the same particle or in different particles. Examples of resin particles containing the resin in the same particle include resin particles containing resin A and resin C, and resin particles containing styrene-acrylic resin and resin C. Examples of resin particles containing the resin in different particles include resin particles containing resin A, resin particles containing styrene-acrylic resin, resin particles containing resin C, and resin particles containing polyurethane resin U.

[0103] In the present invention, the aqueous medium used in the aqueous dispersion is a medium mainly composed of water, and the water content in the aqueous medium is preferably 70% by mass or more, more preferably 80% by mass or more, even more preferably 90% by mass or more, and 100% by mass or less. Deionized water or distilled water is preferred as the water. Other components that can form an aqueous medium together with water include alkyl alcohols having 1 to 5 carbon atoms; dialkyl ketones having 3 to 5 carbon atoms such as acetone and methyl ethyl ketone; and organic solvents that dissolve in water, such as cyclic ethers such as tetrahydrofuran.

[0104] (Method for producing resin particle dispersion) The resin particles may also be manufactured as a resin particle dispersion. The dispersion of resin particles in an aqueous medium can be carried out using known methods, but when the resin is a polyester resin, dispersion by phase inversion emulsification is preferred. Examples of phase inversion emulsification methods include adding an aqueous medium to an organic solvent solution of the resin or to a molten resin and then emulsifying it. The method of adding an aqueous medium to an organic solvent solution of the resin and then emulsifying it 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, but examples include methyl ethyl ketone and ethyl acetate. A neutralizing agent may be added to the organic solvent solution of resin A and / or resin C. Examples of neutralizing agents include basic substances. Examples of basic substances include alkali metal hydroxides such as sodium hydroxide and potassium hydroxide; and nitrogen-containing basic substances such as ammonia, trimethylamine, and diethanolamine. Among these, alkali metal hydroxides such as sodium hydroxide and potassium hydroxide are preferred. The degree of neutralization of resin A and / or resin C 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 80 mol% or less, and even more preferably 70 mol% or less. The degree of neutralization of resin A and / or resin C, which constitute the resin particles, can be determined by the following formula. Degree of neutralization (mol%) = [{Mass of neutralizing agent added (g) / Equivalent amount of neutralizing agent} / [{Weighted average acid value of the resin constituting the resin particles (mgKOH / g) × Mass of the resin constituting the resin particles (g)} / (56 × 1000)]] × 100

[0105] While stirring the organic solvent solution or molten resin, gradually add an aqueous medium to induce phase inversion. The temperature of the organic solvent solution when adding the aqueous medium is preferably above the glass transition temperature of the resin, more preferably above 65°C, even more preferably above 68°C, and preferably below 100°C, more preferably below 95°C, and even more preferably below 90°C.

[0106] After phase inversion emulsification, the organic solvent may be removed from the resulting dispersion by distillation or other means, if necessary. Alternatively, the resin particles may be isolated by filtration or other means. It is preferable to use an aqueous dispersion of resin particles from which the organic solvent has been removed after phase inversion emulsification. In this case, the amount of residual 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.

[0107] Volume-median particle size D of resin particles including amorphous and crystalline resins 50The particle size is preferably 0.03 μm or more, more preferably 0.06 μm or more, even more preferably 0.09 μm or more, and preferably 1 μm or less, more preferably 0.5 μm or less, and even more preferably 0.2 μm or less. Volume-intermediate particle size D of polyurethane resin particles 50 The particle size is preferably 0.01 μm or more, more preferably 0.03 μm or more, and preferably 1 μm or less, more preferably 0.5 μm or less, and even more preferably 0.2 μm or less. The CV value of the resin particles is preferably 15% or more, more preferably 20% or more, and preferably 40% or less, more preferably 35% or less. Volume-intermediate particle size D of resin particles 50 The CV value is measured by the method described in the examples.

[0108] 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 preferably 50% by mass or less, more preferably 40% by mass or less, and even more preferably 35% by mass or less. Note that the solid content represents the total amount of non-volatile components.

[0109] (Method for producing a dispersion of coloring agent particles) The colorant particles are preferably obtained by dispersing titanium dioxide and an aqueous medium using a disperser such as a homogenizer or an ultrasonic disperser as a dispersion of colorant particles. From the viewpoint of improving the dispersion stability of titanium dioxide, this dispersion is preferably carried out in the presence of a surfactant or an addition polymer (hereinafter, the addition polymer used for dispersing the colorant is also referred to as "addition polymer E"). Examples of surfactants include nonionic surfactants, anionic surfactants, and cationic surfactants. For a dispersion of colorant particles using addition polymer E, please refer to Japanese Patent Publication No. 2024-25642.

[0110] The titanium dioxide content in the colorant particle dispersion is preferably 10% by mass or more, more preferably 15% by mass or more, even more preferably 20% by mass or more, and preferably 50% by mass or less, more preferably 45% by mass or less, and even more preferably 35% by mass or less. The solid content concentration of the coloring agent particle dispersion is preferably 10% by mass or more, more preferably 15% by mass or more, even more preferably 20% by mass or more, and preferably 40% by mass or less, more preferably 35% by mass or less.

[0111] Volume-intermediate particle size D of colorant particles 50 The particle size is preferably 0.1 μm or more, more preferably 0.2 μm or more, and preferably 0.45 μm or less, more preferably 0.4 μm or less, and even more preferably 0.35 μm or less. The CV value of the coloring agent particles is preferably 10% or more, more preferably 20% or more, and preferably 45% or less, more preferably 40% or less, and even more preferably 35% or less. Volume-intermediate particle size D of colorant particles 50 The CV value is measured by the method of the example.

[0112] (Method for manufacturing a release agent particle dispersion) Release agent particle dispersions can be obtained using surfactants, but they may also be obtained by mixing the release agent with resin particles. By preparing release agent particles using the release agent and resin particles, the release agent particles are stabilized by the resin constituting the resin particles, making it possible to disperse the release agent in an aqueous medium without using surfactants. Examples of surfactants include nonionic surfactants, anionic surfactants, and cationic surfactants. The resin constituting the resin particles that disperse the mold release agent is preferably a polyester resin, and more preferably an amorphous composite resin D having polyester resin segments and addition polymerization resin segments. For details on the mold release agent particle dispersion and composite resin D, please refer to Japanese Patent Application Publication No. 2024-25642. Alternatively, the aforementioned amorphous polyester resin A may be used.

[0113] Release agent particle volume median particle size D 50 The 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 preferably 1 μm or less, more preferably 0.8 μm or less, and even more preferably 0.6 μm or less. The CV value of the release agent particles is preferably 20% or more, more preferably 30% or more, and preferably 55% or less, more preferably 50% or less, and even more preferably 45% or less. Release agent particle volume median particle size D 50 The CV value is measured by the method described in the examples.

[0114] <<Surfactants>> In the process of agglomerating resin particles, when mixing the dispersions of each particle to prepare a mixed dispersion, the process may be carried out in the presence of a surfactant from the viewpoint of improving the dispersion stability of each particle. Examples of surfactants 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, even more preferably 0.5 parts by mass or more, and preferably 10 parts by mass or less, and more preferably 5 parts by mass or less, per 100 parts by mass of resin particles.

[0115] <<Agglomerants>> In the process of agglomerating resin particles, it is preferable to add a flocculant from the viewpoint of efficiently carrying out the agglomeration. Examples of flocculants include cationic surfactants such as quaternary salts, organic flocculants such as polyethyleneimine, and inorganic flocculants. Examples of inorganic flocculants 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 metal complexes with a valency of 2 or higher. The flocculant is preferably an inorganic metal salt or inorganic ammonium salt with a valency of 1 to 5, more preferably an inorganic metal salt or inorganic ammonium salt with a valency of 1 to 2, even more preferably an inorganic ammonium salt, and even more preferably ammonium sulfate.

[0116] Using a flocculant, for example, 10 to 50 parts by mass of a flocculant per 100 parts by mass of resin particles is added to a mixed dispersion containing resin particles, colorant particles, and release agent particles at a temperature of 0°C to 40°C, and the resin particles, colorant particles, and release agent particles are flocculated in an aqueous medium to obtain flocculated particles 1. From the viewpoint of promoting flocculation, it is preferable to raise the temperature of the dispersion after adding the flocculant.

[0117] Methods for stopping aggregation include cooling the dispersion, adding an aggregation inhibitor, and diluting the dispersion. From the viewpoint of reliably preventing unnecessary aggregation, adding an aggregation inhibitor to stop aggregation is preferred. Furthermore, if the process involves agglomerating shell resin particles for the purpose of manufacturing toner having a core-shell structure, the aggregation process may be carried out without stopping the aggregation, once the aggregated particles 1 have grown to an appropriate particle size. Volume-intermediate particle size D of aggregated particle 1 50 The particle size is preferably 2 μm or more, more preferably 3 μm or more, even more preferably 4 μm or more, and preferably 10 μm or less, more preferably 8 μm or less, and even more preferably 7 μm or less. In the present invention, the process may include a step of using the obtained aggregated particle 1 as a core, attaching and agglomerating shell resin particles to it, and obtaining aggregated particle 2. By including a step of agglomerating the shell resin particles, toner particles having a core-shell structure can be obtained. The resin particles for the shell are preferably amorphous resins, and more preferably amorphous polyester resin A as described above. The resin particle dispersion for the shell is obtained by the same method as the method for producing the resin particle dispersion described above. The mass ratio of shell resin particles to the mass of 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 preferably 20 / 80 or less, more preferably 15 / 85 or less, and even more preferably 10 / 90 or less, from the viewpoint of toner's low-temperature fixation. If the toner manufacturing method includes a step of agglomerating resin particles for the shell, it is preferable to stop the agglomeration in this step when the agglomerated particles 2 have grown to a suitable particle size for toner, and it is preferable to stop the agglomeration by adding an agglomeration inhibitor.

[0118] <<Agglomerating Agent>> As a flocculation inhibitor, surfactants are preferred, and anionic surfactants are more preferred. Examples of anionic surfactants include alkyl sulfates, alkyl ether sulfates, polyoxyalkylene alkyl ether sulfates, alkylbenzene sulfonates, aryl sulfonates, and aryl sulfonic acid formalin condensates, with alkali metal salts of aryl sulfonic acid formalin condensates being preferred, and sodium salts of naphthalene sulfonic acid formalin condensates being more preferred. One or more of these may be used. The flocculation inhibitor may be added in aqueous solution. The amount of flocculation inhibitor added is preferably 1 part by mass or more, more preferably 3 parts by mass or more, and preferably 20 parts by mass or less, and more preferably 15 parts by mass or less, per 100 parts by mass of flocculated particles immediately before adding the flocculation inhibitor.

[0119] <Fusing process> In the fusion process, for example, aggregated particles are fused together in an aqueous medium. Fusion bonding fuses the individual particles contained within the aggregated particles, resulting in fused particles. In the fusion process, from the viewpoint of improving the fusion properties of the aggregated particles, the particles are held at a temperature above the glass transition temperature of the amorphous resin with the highest glass transition temperature among those contained in the aggregated particles. The holding temperature for fusing aggregated particles is preferably 2°C or higher, more preferably 3°C or higher, and even more preferably 5°C or higher than the glass transition temperature of the resin having the highest glass transition temperature among amorphous resins, and preferably 30°C or lower, more preferably 25°C or lower, and even more preferably 20°C or lower than the glass transition temperature of the resin having the highest glass transition temperature among amorphous resins, from the viewpoint of improving the fusion properties of aggregated particles and improving the productivity of toner. In this case, the time for holding the amorphous resin at a temperature above its glass transition temperature is preferably 1 minute or more, more preferably 10 minutes or more, even more preferably 30 minutes or more, and preferably 240 minutes or less, more preferably 180 minutes or less, even more preferably 120 minutes or less, and even more preferably 90 minutes or less. Furthermore, it is preferable to maintain the temperature mentioned above until the desired degree of circularity is achieved.

[0120] Volume median particle size D of fused particles obtained by fusion 50 The particle size is preferably 2 μm or more, more preferably 3 μm or more, even more preferably 4 μm or more, and preferably 10 μm or less, more preferably 8 μm or less, and even more preferably 7 μm or less.

[0121] The circularity of the fused particles obtained by fusion is preferably 0.955 or higher, more preferably 0.960 or higher, and more preferably 0.990 or lower, more preferably 0.985 or lower, and even more preferably 0.980 or lower. It is preferable to terminate the fusion process after achieving the desired degree of circularity described above. The roundness is measured by the method described in the examples.

[0122] <Post-processing steps> A post-processing step may be performed after the fusion step, and toner particles can be obtained by isolating the fused particles. Since the fused particles obtained in the fusion step are present in an aqueous medium, it is preferable to first perform solid-liquid separation. Suction filtration or the like is preferably used for solid-liquid separation. It is preferable to perform washing after solid-liquid separation. At this time, it is also preferable to remove the added surfactant, so it is preferable to wash with an aqueous medium at a temperature below the cloud point of the surfactant. It is preferable to perform washing multiple times. Next, drying is preferable. Examples of drying methods include vacuum constant temperature drying, vibratory fluidized bed drying, spray drying, freeze drying, and flash jet drying.

[0123] [Melting and mixing method] In the present invention, the melt-kneading method involves uniformly mixing, for example, a binder resin, polyurethane resin, titanium dioxide, and optionally an additive such as a mold release agent in a mixer such as a Henschel mixer, and then melt-kneading in a closed-type kneader, a single-screw or twin-screw extruder, an open-roll type kneader, etc. Subsequently, toner particles can be obtained by cooling, pulverizing, and classifying the mixture.

[0124] <External additives> As described above, it is preferable to use toner particles treated with an external additive as the toner of the present invention. Examples of external additives include fine particles of inorganic materials such as hydrophobic silica, titanium dioxide, alumina, cerium oxide, and carbon black, as well as polymer fine particles such as polycarbonate, polymethyl methacrylate, and silicone resin. Among these, hydrophobic silica is preferred. External additives may be used individually or in combination of two or more. In addition, two or more types of hydrophobic silica with different particle sizes may be used. When surface treatment of toner particles is performed using an external additive, the amount of 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, and even more preferably 4 parts by mass or less, per 100 parts by mass of toner particles.

[0125] Toner is used in electrophotographic printing for electrostatic image development. Toner can be used, for example, as a one-component developer, or mixed with a carrier to form a two-component developer. [Examples]

[0126] The present invention will be specifically described below with reference to examples, but the present invention is not limited in any way by these examples. Each property value was measured and evaluated by the following method. In notations such as "alkylene oxide (X)," the number X in parentheses represents the average number of moles of alkylene oxide added.

[0127] [Measurement method] [Softening point, crystallinity index, melting point, and glass transition temperature of resins] (1) Softening point Using a flow tester "CFT-500D" (manufactured by Shimadzu Corporation), 1 g of sample was heated at a heating rate of 6°C / min while a load of 1.96 MPa was applied by a plunger, and the sample was extruded from a nozzle with a diameter of 1 mm and a length of 1 mm. The amount of plunger descent of the flow tester was plotted against temperature, and the temperature at which half of the sample flowed out was defined as the softening point. (2) Crystallinity index Using a differential scanning calorimeter "Q100" (manufactured by T.A. Instruments Japan Co., Ltd.), 0.02 g of the sample was weighed into an aluminum pan and cooled to 0°C at a cooling rate of 10°C / min. The sample was then held for 1 minute, and subsequently heated to 180°C at a heating rate of 10°C / min, and the amount of heat was measured. Among the observed endothermic peaks, the temperature of the peak with the largest peak area was defined as the maximum endothermic peak temperature (1), and the crystallinity index was determined by (softening point (°C)) / (maximum endothermic peak temperature (1) (°C)). (3) Melting point and glass transition temperature Using a differential scanning calorimeter "Q100" (manufactured by T.A. Instruments Japan Co., Ltd.), 0.02 g of the 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 again at a rate of 10°C / min, and the amount of heat was measured. Among the observed endothermic peaks, the temperature of the peak with the largest peak area was defined as the maximum endothermic peak temperature (2). In the case of crystalline resins, this peak temperature was defined as the melting point. Furthermore, in the case of amorphous resins, if a peak was observed, the temperature of that peak was defined as the glass transition temperature. If no peak was observed but a step was observed, the temperature at the intersection of the tangent line showing the maximum slope of the curve in the step portion and the extension of the baseline on the low-temperature side of the step was defined as the glass transition temperature.

[0128] [Acid value of resins] The acid value of the resins was measured according to the neutralization titration method described in JIS K 0070:1992. However, the measurement solvent was tetrahydrofuran for crystalline polyester resins, and a mixed solvent of acetone and toluene (acetone:toluene = 1:1 (volume ratio)) for amorphous polyester resins and styrene-acrylic resins.

[0129] [Melting point of release agent] Using a differential scanning calorimeter "Q100" (manufactured by T.A. Instruments Japan Co., Ltd.), 0.02 g of the 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. Next, the sample was heated again at a rate of 10°C / min, the amount of heat was measured, and the maximum peak temperature of endothermic reaction was defined as the melting point.

[0130] [Average primary particle size of titanium oxide] The average primary particle size of titanium dioxide was calculated by embedding toner particles in acrylic resin, then preparing ultrathin sections of toner approximately 100 μm x 100 μm and 100 nm thick using an ultramicrotome (LEICA ULTRACUT R). Using a transmission electron microscope "JEM-2100" (JEOL Ltd.), 500 primary titanium dioxide particles were extracted by image analysis, their particle sizes were measured, and the average was calculated to determine the number-average particle size. If titanium dioxide particles had both a major and minor axis, the major axis was used for calculation. If 500 primary titanium dioxide particles could not be extracted from a single ultrathin section, image analysis was performed on multiple ultrathin sections.

[0131] [Volume median particle size D of resin particles, colorant particles, polyurethane resin particles, and mold release agent particles] 50 [and CV value] (1) Measuring device: Laser diffraction particle size analyzer "LA-920" (manufactured by Horiba, Ltd.) (2) Measurement conditions: Take the sample dispersion into a measuring cell, add distilled water, and adjust the concentration to the appropriate range for absorbance, using a volume-average particle size D. 50 The volume-average particle size Dv was also measured. Furthermore, the CV value was calculated according to the following formula. CV value (%) = (Standard deviation of particle size distribution / Volume-average particle size Dv) × 100

[0132] [Solid content concentration of resin particle dispersion, colorant particle dispersion, polyurethane resin particle, and mold release agent particle dispersion] Using an infrared moisture meter "FD-230" (manufactured by Kett Scientific Research Institute Co., Ltd.), the moisture content (mass%) of a 5g 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%)

[0133] [Volume-intermediate particle size D of aggregated particles] 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" (manufactured by Beckman Coulter, Inc.) • Electrolyte: "Isoton (registered trademark) II" (manufactured by Beckman Coulter, Inc.) • Measurement conditions: The sample dispersion was added to 100 mL of the electrolyte solution to adjust the concentration so that the particle size of 30,000 particles could be measured in 20 seconds. Then, 30,000 particles were measured again, and the volume median particle size D was determined from the particle size distribution. 50 They sought it.

[0134] [Circularity of fused particles and toner particles] • Measurement device: Flow-type particle image analyzer "FPIA-3000" (manufactured by Sysmex Corporation) • Preparation of dispersion: The dispersion of fused particles was prepared by diluting it with deionized water to a solid content concentration of 0.001 to 0.05% by mass. • Measurement mode: The circularity of the particles was determined using the HPF measurement mode.

[0135] [Toner particle volume medium particle size D] 50 ] The measuring device, aperture diameter, analysis software, and electrolyte are the volume median particle size D of the aggregated particles as described above. 50 The same equipment used in the measurement was employed. • Dispersion: Polyoxyethylene lauryl ether "Emulgen® 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 the measurement sample of dried toner particles was added to 5 mL of the dispersion and dispersed for 1 minute using an ultrasonic disperser. Then, 25 mL of the electrolyte was added and dispersed for another minute using an ultrasonic disperser to prepare the sample dispersion. • Measurement conditions: The sample dispersion is added to 100 mL of the electrolyte to adjust the concentration to a level that allows for the measurement of 30,000 particle sizes in 20 seconds. Then, 30,000 particles are measured, and the volume median particle size D is determined from the particle size distribution. 50 They sought it.

[0136] [Elongation at break of polyurethane resin] A polyurethane resin particle dispersion, adjusted to a solid content concentration of 25% by mass, was placed in a polypropylene tray (300 mm long, 200 mm wide, 40 mm deep) to achieve a dry film thickness of 15 μm. A polyurethane resin film was then created by drying at room temperature. After drying the film at 110°C for 1 hour to remove moisture, five strip-shaped samples (10 mm x 70 mm) were prepared from the film for measurement. The elongation at break of each sample was measured using a tensile testing machine "TENSILON UTM III" (manufactured by A&D Co., Ltd.). The measurement was performed at a temperature of 20°C, a measurement length of 40 mm, and a tensile speed of 4 mm / min. The average value of the elongation at break of the five samples was taken as the elongation at break of the polyurethane.

[0137] [Glass transition temperature of polyurethane resin] For the measurement of the glass transition temperature of polyurethane resin, the film from which moisture had been removed for the fracture elongation measurement described above was used as the sample. Using a differential scanning calorimeter "Q100" (manufactured by T.A. Instruments Japan Co., Ltd.), 0.02 g of the sample was weighed into an aluminum pan, heated to 150°C, and then cooled from 150°C to -70°C at a rate of 10°C / min. The sample was then heated at a rate of 5°C / min, and the amount of heat was measured. When a peak was observed, the temperature of that peak was taken as the glass transition temperature. When no peak was observed but a step was observed, the temperature at the intersection of the tangent line showing the maximum slope of the curve at the step and the extension of the baseline on the low-temperature side of the step was taken as the glass transition temperature.

[0138] [Resin manufacturing] Manufacturing Example A1 (Manufacturing of Resin A-1) A 10L four-necked flask equipped with a nitrogen inlet tube, dehydration tube, stirrer, and thermocouple was purged with nitrogen. 4367g of bisphenol A propylene oxide (2,2) adduct, 1098g of terephthalic acid, 32g of tin(II) di(2-ethylhexanoate), and 3.2g of gallic acid (3,4,5-trihydroxybenzoic acid) were added. Under a nitrogen atmosphere, the reaction system was stirred and heated to 235°C, where it was maintained for 5 hours. After that, the pressure inside the flask was reduced and maintained at 8kPa for 1 hour. After returning to atmospheric pressure, it was cooled to 160°C and maintained at 160°C. A mixture of 1070g of styrene, 267g of stearyl methacrylate, 144g of acrylic acid, and 160g of dibutyl peroxide was added dropwise to the reaction system over 3 hours. The reaction system was then maintained at 160°C for 30 minutes, then the temperature was raised to 200°C, and the pressure in the flask was further reduced to 8 kPa and maintained for 1 hour. After returning to atmospheric pressure, it was cooled to 190°C, and 174 g of fumaric acid, 378 g of sebacic acid, 240 g of trimellitic anhydride, and 3.2 g of 4-tert-butylcatechol were added. The temperature was raised to 210°C at 10°C / hr, and then the reaction was carried out at 4 kPa until the softening point shown in Table 1 was reached to obtain resin A-1 (composite resin). The physical properties are shown in Table 1.

[0139] Manufacturing example A2 (Manufacturing of resin A-2) A 10L stainless steel kettle equipped with a nitrogen inlet tube, a dewatering tube, a stirrer, and a thermocouple contained the polyester resin raw material monomers (excluding trimellitic anhydride) shown in Table 1, an esterification catalyst, and an esterification co-catalyst. The reaction was carried out at 230°C for 8 hours under a nitrogen atmosphere, followed by a reaction under reduced pressure of 1.3kPa to 2.0kPa for 4 hours. After adding trimellitic anhydride, the reaction was carried out at 180°C until the softening point shown in Table 1 was reached to obtain resin A-2 (polyester resin). The physical properties are shown in Table 1.

[0140] Manufacturing example A3 (Manufacturing of resin A-3) The raw material monomers for polyester resins other than isophthalic acid, and the esterification catalyst, as shown in Table 1, were placed in a 10 L four-necked flask equipped with a nitrogen inlet tube, a dehydration tube fitted with a fractionation tube through which 98°C hot water was passed, a stirrer, and a thermocouple. Under a nitrogen atmosphere, the reaction system was held at 180°C for 1 hour, then the temperature was increased from 180°C to 230°C at 10°C / h, and then held at 230°C for 5 hours to allow polycondensation. After cooling to 180°C, isophthalic acid was added to the reaction system, the temperature was increased from 180°C to 230°C at 10°C / h, and the reaction was carried out at 230°C for 1 hour. The reaction was then carried out at 230°C and 10 kPa until the softening point shown in Table 1 was reached to obtain resin A-3 (polyester resin). The physical properties are shown in Table 1.

[0141] [Table 1]

[0142] Manufacturing example A4 (Manufacturing of resin A-4) A 5L four-necked flask equipped with a thermometer, stainless steel stirring rod, fall-flow condenser, dropping funnel, and nitrogen inlet tube contained 2L of xylene. 880g of styrene, 220g of n-butyl acrylate, and 100g of dibutyl peroxide were placed in the dropping funnel. Under a nitrogen atmosphere, the xylene was heated to 135°C while stirring, and the mixture in the dropping funnel was added dropwise over 1 hour. The temperature was then raised to 200°C and maintained at 200°C for 2 hours. Afterward, the pressure inside the flask was reduced and maintained at 8kPa for 1 hour to remove the xylene and obtain resin A-4 (styrene-acrylic resin). The physical properties are shown in Table 2.

[0143] [Table 2]

[0144] [Manufacturing of crystalline polyester resin] Manufacturing example C1 (Manufacturing of resin C-1) A 10L four-necked flask equipped with a nitrogen inlet tube, dehydration tube, stirrer, and thermocouple was purged with nitrogen, and the raw material monomers for the polyester resin shown in Table 3 were added. The reaction system was stirred and heated to 135°C, held at 135°C for 3 hours, and then heated from 135°C to 200°C over 10 hours. Subsequently, 10g of esterification catalyst was added to the reaction system, and after holding at 200°C for another hour, the pressure inside the flask was reduced to 8kPa, and the reaction was carried out under reduced pressure to the softening point shown in Table 3 to obtain resin C-1. The physical properties are shown in Table 3.

[0145] [Table 3]

[0146] [Manufacturing of resin particle dispersions] Manufacturing Example X1 (Manufacturing of Resin Particle Dispersion X-1) In a 3L container equipped with a stirrer, reflux condenser, dropping funnel, thermometer, and nitrogen inlet tube, 400g of resin A-1, 100g of resin C-1, and 500g of methyl ethyl ketone were placed, and the resins were dissolved at 73°C for 2 hours. To the resulting solution, a 5% by mass aqueous sodium hydroxide solution was added to achieve a degree of neutralization of 60 mol% relative to the acid value of the resin, and the mixture was stirred for 30 minutes. Next, while maintaining the temperature at 73°C, 1000 g of deionized water was added over 60 minutes while stirring at 200 r / min (peripheral speed 64 m / min) to induce phase inversion emulsification. While continuing to maintain the temperature at 73°C, methyl ethyl ketone was removed under reduced pressure to obtain a resin dispersion. Afterward, the dispersion was cooled to 30°C while continuing to stir, and then deionized water was added to achieve a solid content concentration of 25% by mass to obtain resin particle dispersion X-1. The physical properties are shown in Table 4.

[0147] Manufacturing examples X2 and X3 (Manufacturing of resin particle dispersions X-2 and X-3) Resin particle dispersions X-2 and X-3 were obtained in the same manner as in manufacturing example X1, except that the type of resin was changed as shown in Table 4. The physical properties are shown in Table 4.

[0148] Manufacturing Example X4 (Manufacturing of Resin Particle Dispersion X-4) In a 3L container equipped with a stirrer, reflux condenser, dropping funnel, thermometer, and nitrogen inlet tube, 400g of resin A-4, 100g of resin C-1, 500g of ethyl acetate, and 100g of 16% by mass sodium dodecylbenzenesulfonate aqueous solution "Neoperex G-15" (manufactured by Kao Corporation, anionic surfactant) were added and dissolved at 70°C for 2 hours. To the obtained solution, 1400g of deionized water at 70°C was added, and dispersion treatment was performed using an ultrasonic homogenizer "UP-400S" (manufactured by Hielscher) at an output of 350W for 30 minutes. After that, while maintaining the temperature at 70°C, the ethyl acetate was removed by vacuum distillation, and deionized water was added to adjust the solid content concentration to 25% by mass to obtain resin particle dispersion X-4. The physical properties are shown in Table 4.

[0149] [Table 4]

[0150] Manufacturing Examples U1~U7, U'11 (Manufacturing of polyurethane resin particle dispersions U-1~U-7, U'-11) Polyurethane resin particle dispersions U-1 to U-7 and U'-11 were obtained by adding deionized water to commercially available polyurethane resin particle dispersions listed in Table 5 to a solid content concentration of 25% by mass.

[0151] [Table 5]

[0152] [Manufacturing of colorant particle dispersion] Manufacturing Example E1 (Manufacturing of Colorant Particle Dispersion E-1) In a 2L polyethylene bottle, 16.32g (2.61g active ingredient) of 16% by mass sodium dodecylbenzenesulfonate aqueous solution "Neoperex G-15" (manufactured by Kao Corporation, anionic surfactant), 120g of titanium dioxide (CR-80, manufactured by Ishihara Sangyo Co., Ltd., rutile type, Al, Si treated, average primary particle size 0.25μm), and 122.4g of water were added. 2952g of zirconia beads were then added, and the mixture was dispersed at 25°C for 8 hours using a tabletop pot mill stand (manufactured by AS ONE Corporation). The zirconia beads were removed using a mesh, deionized water was added, and the solid content concentration was adjusted to 30% by mass to obtain colorant particle dispersion E-1. The volume-median particle size D of the colorant particles was determined. 50 The particle size was 0.28 μm, and the CV value was 30%.

[0153] [Manufacturing of mold release agent particle dispersion] Manufacturing Example W1 (Manufacturing of Release Agent Particle Dispersion W-1) In a 1 L beaker, 200 g of deionized water and 5.36 g of the anionic surfactant "Latemul® ASK" (manufactured by Kao Corporation, aqueous solution of dipotassium alkenylsuccinate, effective concentration 28% by mass) were mixed. 50 g of paraffin wax "HNP-9" (manufactured by Nippon Seiro Co., Ltd., melting point 75°C) was added to the mixture, and the mixture was dispersed for 20 minutes using an ultrasonic homogenizer "US-600T" (manufactured by Nippon Seiki Seisakusho Co., Ltd.) while maintaining the temperature at 95-98°C, after which it was cooled to 25°C. Deionized water was added to adjust the solid content concentration to 20% by mass to obtain the release agent particle dispersion W-1. The median particle size D of the release agent particles 50 The particle size was 0.42 μm, and the CV value was 39%.

[0154] [Toner manufacturing] Example 1 (Manufacturing of Toner 1) In a 3L four-necked flask equipped with a reflux condenser, stirrer, and thermocouple, 300g of resin particle dispersion X-1, 45g of polyurethane resin particle dispersion U-1, 176g of coloring agent particle dispersion E-1, 32g of mold release agent particle dispersion W-1, and 159g of deionized water were added and mixed at 25°C to obtain a mixture. Separately, a solution was prepared by dissolving 40g of ammonium sulfate in 1102g of deionized water and adding a 4.8% by mass potassium hydroxide aqueous solution to adjust the pH to 8.2. This solution was added dropwise to the mixture over 10 minutes at 25°C while stirring. After addition, the temperature was raised to 58°C over 2 hours to determine the volume median particle size D of the aggregated particles. 50 The mixture was maintained at 58°C until it reached a size of 6.0 μm, and a dispersion of aggregated particles 1 was obtained. To the dispersion of the obtained aggregated particles 1, 72 g of a 20% by mass aqueous solution of "Demol MS" (manufactured by Kao Corporation), the sodium salt of naphthalene sulfonic acid formalin condensate, and 792 g of deionized water were added. Then, the temperature was raised to 75°C over 1 hour and held at 75°C until the circularity reached 0.970, thereby obtaining a dispersion of fused particles in which the aggregated particles 1 had fused together. The resulting dispersion of fused particles was cooled to 30°C, and the solid components were separated by suction filtration. After washing with deionized water at 25°C, the dispersion was filtered by suction filtration at 25°C for 2 hours. Subsequently, vacuum drying was performed at 33°C for 24 hours using a vacuum constant-temperature dryer "DRV622DA" (manufactured by ADVANTEC) to obtain toner particles 1. The physical properties of toner particles 1 are shown in Table 6. To 100 parts by mass of toner particles 1, 2.5 parts by mass of hydrophobic silica "RY50" (manufactured by Nippon Aerosil Co., Ltd., average particle size: 0.04 μm) and 1 part by mass of hydrophobic silica "Cabosil® TS720" (manufactured by Cabot, average particle size: 0.012 μm) were mixed in a Henschel mixer and stirred, and then passed through a 150-mesh sieve to obtain toner 1.

[0155] [Toner Evaluation] The obtained toner 1 was evaluated as follows.

[0156] [Evaluation of the adhesion of printed coatings to film] Using a commercially available printer, "COREFIDO C712dnw" (manufactured by OKI Electric Industry Co., Ltd.), the toner adhesion amount was measured on the corona-treated surface of a polyethylene terephthalate (PET) film "FE-2001#25" (manufactured by Futamura Chemical Co., Ltd.) cut to A4 size, with a toner adhesion amount of 0.98 to 1.02 mg / cm². 2 The resulting solid image was output without being fixed. Next, a modified version of the printer with a variable-temperature fuser was prepared. The fuser temperature was set to 150°C, and toner was fixed at a rate of 1.7 seconds per sheet in A4 portrait orientation to obtain printed materials, which were then left to stand at 25°C for 7 days. Cellophane tape "Cellotape CT12" (product name, manufactured by Nichiban Co., Ltd.) was applied to the solid image area, and the tape was peeled off at a speed of 10 cm / sec at an angle of 90°. A sheet of black high-quality paper, "Extra Thick Black" (manufactured by Hokuetsu Corporation), was placed under the printed material. The reflected image density of the solid image area and the non-image area of ​​the printed material were measured using a colorimeter, "SpectroEye" (manufactured by X-Rite, lighting conditions: standard light source D50, observation field of view 2°, density standard DINNB, absolute white standard). The value calculated as "100 × (1 - reflected image density of solid image area / reflected image density of non-image area)" was defined as the opacity rate (%). The opacity rate (%) of the solid image area of ​​the printed material before and after applying the tape was calculated using the method described above. The value calculated as "100 × opacity rate after tape removal / opacity rate before tape removal" was defined as the fixation rate (%). A higher value indicates better image fixation to the resin film.

[0157] Examples 2-10, Comparative Example 1 (Manufacturing of Toners 2-10 and C1) In Example 1, toner particles 2-10, C1 and toner 2-10, C1 were obtained in the same manner as in Example 1, except that the resin particle dispersion or polyurethane resin particle dispersion was changed as shown in Table 6. The physical properties of toner particles 2-10, C1 and the evaluation results of toner 2-10, C1 are shown in Table 6.

[0158] Examples 11 and 12 (Manufacturing of toners 11 and 12) In Example 1, toner particles 11, 12 and toner 11, 12 were obtained in the same manner except that the fusion temperature was changed as shown in Table 6. The physical properties of toner particles 11, 12 and the evaluation results of toner 11, 12 are shown in Table 6.

[0159] Example 13 (Production of toner 13 by melt-mixing method) 100 parts by mass of binder resin (amorphous polyester resin A-1 / crystalline polyester resin C-1 = 80 / 20 (mass ratio)), 15 parts by mass of thermoplastic polyurethane elastomer "Elastoran ET370 (manufactured by BASF, elongation at break 800%, glass transition temperature -50℃)", 60 parts by mass of titanium dioxide (CR-80, rutile type, Al, Si treated, average primary particle size "0.25 μm" manufactured by Ishihara Sangyo Co., Ltd.), and 7 parts by mass of paraffin wax "HNP-9" as a release agent were thoroughly mixed in a Henschel mixer, and then 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. The screw rotation speed was 200 r / min, the heating setting temperature inside the screw was 90℃, the temperature of the kneaded material was 140℃, the supply rate of the kneaded material was 10 kg / h, and the average residence time was approximately 18 seconds. The resulting mixture was cooled from 140°C to 50°C in 1.5 hours, then rolled and cooled at 50°C using cooling rollers. After standing at 45°C for 4 hours, it was crushed and classified using a jet mill to obtain toner particles 13. The physical properties of the toner particles 13 are shown in Table 7. To 100 parts by mass of toner particles 13, 2.5 parts by mass of hydrophobic silica "RY50" (manufactured by Nippon Aerosil Co., Ltd., average particle size: 0.04 μm) and 1 part by mass of hydrophobic silica "Cabosil® TS720" (manufactured by Cabot Japan Co., Ltd., average particle size: 0.012 μm) were mixed in a Henschel mixer and stirred, and the mixture was passed through a 150-mesh sieve to obtain toner 13. The physical properties of the toner particles 13 and the evaluation results of the toner 13 are shown in Table 7.

[0160] Comparative Example 2 (Manufacturing of Toner C2) In Example 1, the polyurethane resin particle dispersion was replaced with a vinyl ester copolymer acrylic resin particle dispersion DXV.4051 (manufactured by VANORA, with a break elongation of 500%, a glass transition temperature of 10°C, and a medium volume particle size D). 50 Toner particles C2 and toner C2 were obtained in the same manner, except that the particle size was changed to 0.10 μm and the CV value was 27%). The elongation at break of the acrylic resin was determined in the same manner as the elongation at break of the polyurethane resin. Table 6 shows the physical properties of toner particles C2 and the evaluation results of toner C2.

[0161] [Table 6]

[0162] [Table 7]

[0163] Tables 6 and 7 show that the toner of the present invention exhibits excellent adhesion to resin films regardless of whether it is manufactured by the emulsification agglutination method or the melt kneading method (Examples 1-13). In contrast, images obtained using a toner containing polyurethane resin with a breaking elongation of less than 200% (5%) (Comparative Example 1) and images obtained using a toner containing acrylic resin (Comparative Example 2) both showed poor adhesion to resin films.

Claims

1. The toner contains a binder resin, polyurethane resin U, and titanium dioxide. A white toner for electrostatic image development, wherein the polyurethane resin U has a breaking elongation of 200% to 1500%.

2. The white toner for electrostatic image development according to claim 1, wherein the glass transition temperature of the polyurethane resin U is -60°C or higher and 95°C or lower.

3. The white toner for electrostatic image development according to claim 1 or 2, wherein the binder resin contains a crystalline polyester resin C.

4. The white toner for electrostatic image development according to claim 1 or 2, wherein the content of polyurethane resin U in the toner particles is 3 parts by mass or more and 50 parts by mass or less per 100 parts by mass of binder resin.

5. The electrostatic image developing white toner according to claim 1 or 2, wherein the polyurethane resin U comprises at least one selected from polyether-based polyurethane resins and polycarbonate-based polyurethane resins.

6. The process includes steps of aggregating and fusing binder resin particles, polyurethane resin U particles, and titanium oxide particles in an aqueous medium. A method for manufacturing a white toner for electrostatic image development, wherein the elongation at break of the polyurethane resin U is 200% or more and 1500% or less.

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