Toner for developing electrostatic images

Abstract

To provide a toner for electrostatic charge image development which suppresses curl of an image and is excellent in heat resistant storage property.SOLUTION: A toner for electrostatic charge image development is a toner for electrophotography containing a binder resin and inorganic fine particles, wherein the binder resin contains a crystalline polyester resin C that is a polycondensate of an alcohol component containing ethylene glycol and a carboxylic acid component containing a dicarboxylic acid-based compound having 6 or more and 16 or less carbon atoms, an addition polymerization-based resin segment that is an addition polymer of a raw material monomer containing a polyester resin segment and a styrene compound, and an amorphous composite resin A including a structural unit derived from an amphoteric monomer obtained by coupling the polyester resin segment and the addition polymerization-based resin segment through a covalent bond, and the content of the inorganic fine particles is 50 pts.mass or more and 150 pts.mass or less with respect to 100 pts.mass of the binder resin.SELECTED DRAWING: None

Description

[Technical Field]

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

[0002] Additives that are added internally to toner particles include titanium oxide as a colorant for white toner, and inorganic fine particles such as magnetic powder that imparts magnetism to the toner.

[0003] Patent Document 1 discloses a white toner for developing electrostatic images, which contains a colorant and a binder resin consisting of a crystalline resin and a non-crystalline resin, and is characterized in that the content of the crystalline resin in the toner is 5 to 25% by mass, and the content of the colorant in the toner is 15 to 40% by mass.

[0004] Patent Document 2 discloses an image forming method having a thermal fixing process step in which a white toner image made of a white toner containing a first binder resin and a first colorant and a color toner image made of a non-white color toner containing a second binder resin and a second colorant are layered in this order on a recording medium and thermally fixed, wherein the second binder resin contains a vinyl resin and a hybrid crystalline polyester resin, and the storage modulus G1' of the white toner at 90°C and the storage modulus G2' of the non-white color toner at 90°C satisfy a predetermined relational expression.

[0005] Patent Document 3 discloses a toner having toner particles containing a binder resin, a crystalline material A, and magnetic particles, characterized in that the magnetic particles satisfy all of the following requirements (i) to (iii): (i) It has an octahedral shape and has a convex portion on the flat surface of the octahedron. (ii) A magnetite core having a coating layer formed on the surface of the magnetite core. (iii) The coating layer contains, in addition to an oxide containing iron, an oxide containing silicon and aluminum. Contains at least one oxide selected from the group consisting of oxides containing [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2007-33719 [Patent Document 2] Japanese Patent Application Publication No. 2019-53219 [Patent Document 3] Japanese Patent Application Publication No. 2017-122874 Summary of the Invention [Problem to be solved by the invention]

[0007] However, toners containing a large amount of inorganic fine particles have the problem that the image tends to curl after printing. Furthermore, when a crystalline polyester resin having a high affinity with an amorphous polyester resin is used, curling can be suppressed, but there is a problem with heat-resistant storage stability.

[0008] The present invention relates to a toner for developing electrostatic images, which prevents image curling and has excellent heat resistance and storage stability. [Means for solving the problem]

[0009] The present invention provides an electrophotographic toner containing a binder resin and inorganic fine particles, wherein the binder resin comprises a crystalline polyester resin C which is a polycondensation product of an alcohol component containing ethylene glycol and a carboxylic acid component containing a dicarboxylic acid compound having 6 to 16 carbon atoms; a polyester resin segment; an addition polymerization resin segment which is an addition polymerization product of raw material monomers containing a styrene compound; and a polymerizable composition comprising the polyester resin segment and the addition polymerization resin segment. of Attached via covalent bonds LetThe toner for developing electrostatic images contains an amorphous composite resin A containing structural units derived from a bireactive monomer, and the content of the inorganic fine particles is 50 parts by mass or more and 150 parts by mass or less per 100 parts by mass of the binder resin. [Effects of the Invention]

[0010] The toner for developing electrostatic images of the present invention exhibits the effects of suppressing image curl and having excellent heat-resistant storage stability. DETAILED DESCRIPTION OF THE INVENTION

[0011] The toner for developing electrostatic images of the present invention contains a binder resin and a colorant, and has a major feature in that the binder resin contains a crystalline polyester resin C which is a polycondensate of raw material monomers including a specific monomer, and an amorphous composite resin A which has a polyester resin segment and an addition polymerization resin segment. Although the details are unknown, it is presumed that the effects of the present invention are achieved by the following mechanism.

[0012] The curl of a fixed image occurs when the toner layer shrinks as it changes from a molten state to a solid state after fixing. If the crystallization of the crystalline component (crystalline polyester resin) in the toner progresses slowly, the tension within the toner layer increases, causing the curl to become larger. In particular, toner containing a large amount of inorganic fine particles causes significant curling of the image after fixing. This is thought to be because the difference in cooling speed between the inorganic fine particles, which have a relatively high thermal conductivity, and the resin component, which has a low thermal conductivity, causes uneven cooling of the crystalline component in the toner, resulting in large tension when the toner layer changes from a molten state to a solid state after fixing. On the other hand, regarding the influence of crystalline polyester resin and amorphous resin, if the crystalline polyester resin crystallizes after the amorphous resin becomes solid, curling will increase. Therefore, if the crystalline polyester resin is crystallized before the amorphous resin becomes completely solid, curling can be suppressed. Furthermore, since the larger the crystal size of the crystalline polyester resin, curling will also increase. Therefore, finely dispersing the crystalline polyester resin and then crystallizing it can disperse tension and suppress curling. Thus, curling can be suppressed by finely dispersing the crystalline polyester resin using a crystalline polyester resin that has a high affinity with the amorphous polyester resin. However, finely dispersing the crystalline polyester resin slows down crystal recovery, making heat-resistant storage stability an issue. Therefore, in the present invention, by combining a crystalline polyester resin with an amorphous composite resin, which allows for both rapid crystallization of the crystalline polyester resin and fine dispersion of the crystalline polyester resin, it has become possible to suppress image curling without impairing heat-resistant storage stability.

[0013] In the present invention, crystalline polyester resin C is a polycondensate of an alcohol component containing ethylene glycol and a carboxylic acid component containing a dicarboxylic acid compound having 6 to 16 carbon atoms. Crystalline polyester resin C has low affinity with the addition polymerization resin segment of amorphous composite resin A, so it crystallizes quickly, and also has high affinity between the ethylene glycol-derived portion of crystalline polyester resin C and the polyester resin segment of amorphous composite resin A, so crystalline polyester resin C is finely dispersed in amorphous composite resin A.

[0014] The crystallinity of a resin is expressed by the crystallinity index, which is defined as the ratio of the softening point to the maximum endothermic peak temperature measured by a differential scanning calorimeter, i.e., the value of [softening point / maximum endothermic peak temperature]. A crystalline resin is a resin having a crystallinity index of 0.6 or more, preferably 0.7 or more, more preferably 0.9 or more, and 1.4 or less, preferably 1.2 or less, more preferably 1.1 or less. On the other hand, an amorphous resin is a resin in which no endothermic peak is observed, or if an endothermic peak is observed, the resin has a crystallinity index of more than 1.4, preferably more than 1.5, more preferably 1.6 or more, or less than 0.6, preferably 0.5 or less. The crystallinity of a resin can be adjusted by the types and ratios of raw material monomers, and production conditions (e.g., reaction temperature, reaction time, cooling rate), etc. The maximum endothermic peak temperature refers to the temperature of the peak with the largest peak area among the observed endothermic peaks. For crystalline resins, the maximum endothermic peak temperature is the melting point.

[0015] From the viewpoint of heat-resistant storage stability, the content of ethylene glycol in the alcohol component is preferably 70 mol% or more, more preferably 80 mol% or more, even more preferably 90 mol% or more, even more preferably 95 mol% or more, and even more preferably 100 mol%.

[0016] Examples of alcohol components other than ethylene glycol include aliphatic diols other than ethylene glycol such as 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, neopentyl glycol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, and 1,12-dodecanediol; aromatic diols such as alkylene oxide adducts of bisphenol A; bisphenol A, hydrogenated bisphenol A, sorbitol, pentaerythritol, glycerin, and trimethylolpropane; and trihydric or higher alcohols.

[0017] The carboxylic acid component contains a dicarboxylic acid compound having 6 to 16 carbon atoms from the viewpoint of achieving both low-temperature fixability and heat-resistant storage stability.

[0018] From the viewpoint of hydrophobicity, the carbon number of the dicarboxylic acid compound is 6 or more, preferably 10 or more, more preferably 12 or more, and from the viewpoint of low-temperature fixability, it is 16 or less, preferably 14 or less. In this specification, when the dicarboxylic acid compound is an alkyl ester, the carbon number of the alkyl group is not included in the above carbon number.

[0019] The dicarboxylic acid compound having 6 to 16 carbon atoms may be an aliphatic dicarboxylic acid compound or an aromatic dicarboxylic acid compound, but from the viewpoint of low-temperature fixability, an aliphatic dicarboxylic acid compound is preferred.

[0020] Examples of the aliphatic dicarboxylic acid compound having 6 to 16 carbon atoms include adipic acid (number of carbon atoms: 6), suberic acid (number of carbon atoms: 8), azelaic acid (number of carbon atoms: 9), sebacic acid (number of carbon atoms: 10), dodecanedioic acid (number of carbon atoms: 12), tetradecanedioic acid (number of carbon atoms: 14), succinic acid having an alkyl or alkenyl group in the side chain, anhydrides of these acids, and alkyl esters of these acids having 1 to 3 carbon atoms.

[0021] Examples of aromatic dicarboxylic acid compounds having 6 to 16 carbon atoms include phthalic acid, isophthalic acid, terephthalic acid, anhydrides of these acids, and alkyl esters of these acids having 1 to 3 carbon atoms.

[0022] From the viewpoint of hydrophobicity, the content of the dicarboxylic acid compound having 6 to 16 carbon atoms in the carboxylic acid component is preferably 50 mol% or more, more preferably 60 mol% or more, even more preferably 70 mol% or more, and even more preferably 80 mol% or more, and is 100 mol% or less, preferably 98 mol% or less, and more preferably 95 mol% or less.

[0023] Examples of other carboxylic acid components include aliphatic dicarboxylic acid compounds other than those mentioned above, aromatic dicarboxylic acid compounds, and trivalent or higher carboxylic acid compounds.

[0024] Furthermore, the alcohol component and / or carboxylic acid component of the crystalline polyester resin C preferably contain a monofunctional monomer. From the viewpoint of improving low-temperature fixability and the brightness of the toner powder, the monofunctional monomer is preferably an aliphatic monofunctional monomer having 10 or more carbon atoms. Furthermore, from the viewpoint of reactivity, a monofunctional alcohol or carboxylic acid is preferred, and a monofunctional carboxylic acid is more preferred.

[0025] Examples of monofunctional monomers contained in the alcohol component include aliphatic monoalcohols such as capric alcohol, lauryl alcohol, myristyl alcohol, palmityl alcohol, stearyl alcohol, and behenyl alcohol.

[0026] Examples of monofunctional monomers contained in the carboxylic acid component include aliphatic monocarboxylic acids such as capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, and behenic acid, and aliphatic monocarboxylic acid compounds such as alkyl esters of these acids in which the alkyl group has 1 to 3 carbon atoms.

[0027] From the viewpoint of hydrophobicity, the number of carbon atoms in the monofunctional monomer is preferably 10 or more, more preferably 12 or more, and even more preferably 14 or more, and from the viewpoint of low-temperature fixability, it is preferably 22 or less, more preferably 20 or less, and even more preferably 18 or less. When the monofunctional monomer is an alkyl ester of an aliphatic monocarboxylic acid compound, the number of carbon atoms in the alkyl group is not included in the above carbon number.

[0028] The content of the monofunctional monomer in the raw material monomers (the total amount of the alcohol component and the carboxylic acid component) is preferably 1 mol% or more, more preferably 3 mol% or more, and even more preferably 5 mol% or more, and from the viewpoint of low-temperature fixability, it is preferably 30 mol% or less, more preferably 20 mol% or less, and even more preferably 15 mol% or less.

[0029] In this specification, macromonomers and hydroxycarboxylic acids are not included in the alcohol component and carboxylic acid component.

[0030] The equivalent ratio of the carboxyl groups of the carboxylic acid component to the hydroxyl groups of the alcohol component (COOH groups / OH groups) is preferably 0.8 or more, more preferably 0.9 or more, and preferably 1.2 or less, more preferably 1.1 or less.

[0031] Crystalline polyester resin C can be produced, for example, by polycondensing an alcohol component and a carboxylic acid component in an inert gas atmosphere, preferably in the presence of an esterification catalyst, and if necessary, in the presence of an esterification promoter, a polymerization inhibitor, etc., at a temperature preferably of 120°C or higher and 230°C or lower.

[0032] Examples of the esterification catalyst include tin compounds such as dibutyltin oxide and tin(II) 2-ethylhexanoate, and titanium compounds such as titanium diisopropylate bistriethanolamine. The amount of the esterification catalyst used is preferably 0.01 parts by mass or more, more preferably 0.1 parts by mass or more, and preferably 1.5 parts by mass or less, more preferably 1 part by mass or less, per 100 parts by mass of the alcohol component and the carboxylic acid component combined. Examples of the esterification promoter include gallic acid. The amount of the esterification promoter used is preferably 0.001 parts by mass or more, more preferably 0.01 parts by mass or more, and preferably 0.5 parts by mass or less, more preferably 0.1 parts by mass or less, per 100 parts by mass of the alcohol component and the carboxylic acid component combined. Examples of the polymerization inhibitor include tert-butylcatechol. The amount of the polymerization inhibitor used is preferably 0.001 part by mass or more, more preferably 0.01 part by mass or more, and preferably 0.5 part by mass or less, more preferably 0.1 part by mass or less, per 100 parts by mass of the total amount of the alcohol component and the carboxylic acid component.

[0033] In the present invention, the polyester resin may be modified to such an extent that its properties are not substantially impaired. Examples of modified polyester resins include polyester resins grafted or blocked with phenol, urethane, epoxy, or the like, by the methods described in JP-A Nos. 11-133668, 10-239903, and 8-20636. Among the modified polyester resins, urethane-modified polyester resins in which polyester resins are urethane-extended with a polyisocyanate compound are preferred.

[0034] The softening point of the crystalline polyester resin C is preferably 50°C or higher, more preferably 65°C or higher, and even more preferably 70°C or higher from the viewpoint of heat-resistant storage stability, and is preferably 120°C or lower, more preferably 110°C or lower from the viewpoint of low-temperature fixability.

[0035] The melting point of the crystalline polyester resin C is preferably 60°C or higher, more preferably 70°C or higher, from the viewpoint of heat-resistant storage stability, and is preferably 130°C or lower, more preferably 120°C or lower, from the viewpoint of low-temperature fixability.

[0036] The acid value of the crystalline polyester resin C is preferably 1 mgKOH / g or more, more preferably 3 mgKOH / g or more, from the viewpoint of low-temperature fixability, and is preferably 20 mgKOH / g or less, more preferably 15 mgKOH / g or less, from the viewpoint of improving the brightness of the toner powder.

[0037] The content of the crystalline polyester resin C in the binder resin is preferably 2% by mass or more, more preferably 5% by mass or more, and even more preferably 8% by mass or more, from the viewpoint of low-temperature fixability, and is preferably 25% by mass or less, more preferably 20% by mass or less, and even more preferably 15% by mass or less, from the viewpoint of dispersibility in the toner.

[0038] The amorphous composite resin A includes a polyester resin segment, an addition polymerization resin segment which is an addition polymer of raw material monomers including a styrene compound, and a mixture of the polyester resin segment and the addition polymerization resin segment. of Attached via covalent bonds Let It is an amorphous composite resin containing structural units derived from a bireactive monomer.

[0039] The polyester resin segment is preferably a polycondensate of an alcohol component containing an alkylene oxide adduct of bisphenol A and a carboxylic acid component.

[0040] Examples of alkylene oxide adducts of bisphenol A include those represented by the formula (I):

[0041] [ka]

[0042] (wherein OR and RO are oxyalkylene groups, R is an ethylene group and / or a propylene group, x and y are the average number of moles of alkylene oxide added and are each a positive number, and the sum of x and y is 1 or more, preferably 1.5 or more, and 16 or less, preferably 8 or less, more preferably 6 or less, and even more preferably 4 or less.) A compound represented by the following formula is preferred.

[0043] From the viewpoint of low-temperature fixability, the content of the alkylene oxide adduct of bisphenol A in the alcohol component is preferably 70 mol% or more, more preferably 80 mol% or more, even more preferably 90 mol% or more, even more preferably 95 mol% or more, and even more preferably 100 mol%.

[0044] Examples of other alcohol components include aliphatic diols, bisphenol A, hydrogenated bisphenol A, sorbitol, pentaerythritol, glycerin, tri- or higher hydric alcohols such as trimethylolpropane, and the like.

[0045] The carboxylic acid component preferably contains an aromatic dicarboxylic acid compound and / or a succinic acid derivative substituted with a hydrocarbon group.

[0046] Examples of aromatic dicarboxylic acid compounds include phthalic acid, isophthalic acid, terephthalic acid, anhydrides of these acids, and alkyl esters of these acids having 1 to 3 carbon atoms.

[0047] From the viewpoint of the hydrophilic / hydrophobic balance with the crystalline polyester resin C, the content of the aromatic dicarboxylic acid compound in the carboxylic acid component is preferably 40 mol% or more, more preferably 50 mol% or more, and is preferably 80 mol% or less, more preferably 65 mol% or less.

[0048] The hydrocarbon group in the succinic acid derivative substituted with a hydrocarbon group is preferably an alkyl group or an alkenyl group.Therefore, specific examples of the succinic acid derivative substituted with a hydrocarbon group include dodecylsuccinic acid, dodecenylsuccinic acid, tetrapropenylsuccinic acid, decenylsuccinic acid, their acid anhydrides, and their alkyl esters having 1 to 3 carbon atoms.Among these, from the viewpoint of low-temperature fixability, dodecenylsuccinic acid, tetrapropenylsuccinic acid, or their acid anhydrides are preferred, and dodecenylsuccinic anhydride is more preferred.

[0049] From the viewpoint of hydrophobicity, the number of carbon atoms in the hydrocarbon group in the succinic acid derivative is preferably 8 or more, more preferably 10 or more, even more preferably 12 or more, and preferably 20 or less, more preferably 18 or less, even more preferably 16 or less.

[0050] From the viewpoint of hydrophobicity, the succinic acid derivative preferably contains at least one or two or more succinic acids selected from the group consisting of succinic acids substituted with alkyl groups having from 10 to 18 carbon atoms and succinic acids substituted with alkenyl groups having from 10 to 18 carbon atoms, and more preferably contains at least one or two or more succinic acids selected from the group consisting of succinic acids substituted with alkyl groups having from 12 to 16 carbon atoms and succinic acids substituted with alkenyl groups having from 12 to 16 carbon atoms.

[0051] The content of the succinic acid derivative in the carboxylic acid component is preferably 5 mol% or more, more preferably 10 mol% or more, and even more preferably 15 mol% or more, from the viewpoint of the hydrophilic / hydrophobic balance with the crystalline polyester resin C, and is preferably 40 mol% or less, more preferably 35 mol% or less, and even more preferably 30 mol% or less, from the viewpoint of the hydrophilic / hydrophobic balance with the crystalline polyester resin C.

[0052] Examples of carboxylic acid components other than aromatic dicarboxylic acid compounds and succinic acid derivatives include aliphatic dicarboxylic acid compounds and trivalent or higher carboxylic acid compounds.

[0053] Examples of the aliphatic dicarboxylic acid compounds include aliphatic dicarboxylic acids such as oxalic acid, malonic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, and adipic acid, anhydrides of these acids, and alkyl esters in which the alkyl group has 1 to 3 carbon atoms.

[0054] Examples of the trivalent or higher carboxylic acid compound include trimellitic acid, pyromellitic acid, anhydrides of these acids, and alkyl esters of these acids having 1 to 3 carbon atoms.

[0055] From the viewpoint of adjusting the softening point, the content of the trivalent or higher carboxylic acid compound in the carboxylic acid component is preferably 3 mol% or more, more preferably 10 mol% or more, and is preferably 40 mol% or less, more preferably 30 mol% or less.

[0056] The alcohol component may contain a monohydric alcohol, and the carboxylic acid component may contain a monocarboxylic acid compound, as appropriate.

[0057] The equivalent ratio of the carboxyl groups of the carboxylic acid component to the hydroxyl groups of the alcohol component (COOH groups / OH groups) is preferably 0.6 or more, more preferably 0.7 or more, even more preferably 0.75 or more, and is preferably 1.2 or less, more preferably 1.15 or less.

[0058] The polyester resin segment can be produced, for example, by polycondensing an alcohol component and a carboxylic acid component in an inert gas atmosphere, preferably in the presence of an esterification catalyst, and if necessary, in the presence of an esterification promoter, a polymerization inhibitor, etc., at a temperature of preferably 130°C or higher, more preferably 170°C or higher, and preferably 250°C or lower, more preferably 240°C or lower.

[0059] Examples of the esterification catalyst include tin compounds such as dibutyltin oxide and tin(II) 2-ethylhexanoate, and titanium compounds such as titanium diisopropylate bistriethanolamine. The amount of the esterification catalyst used is preferably 0.01 parts by mass or more, more preferably 0.1 parts by mass or more, and preferably 1.5 parts by mass or less, more preferably 1 part by mass or less, per 100 parts by mass of the alcohol component and the carboxylic acid component combined. Examples of the esterification promoter include gallic acid. The amount of the esterification promoter used is preferably 0.001 parts by mass or more, more preferably 0.01 parts by mass or more, and preferably 0.5 parts by mass or less, more preferably 0.1 parts by mass or less, per 100 parts by mass of the alcohol component and the carboxylic acid component combined. Examples of the polymerization inhibitor include tert-butylcatechol. The amount of the polymerization inhibitor used is preferably 0.001 part by mass or more, more preferably 0.01 part by mass or more, and preferably 0.5 part by mass or less, more preferably 0.1 part by mass or less, per 100 parts by mass of the total amount of the alcohol component and the carboxylic acid component.

[0060] The addition polymerization resin segment is an addition polymer of raw material monomers containing a styrene compound, such as styrene, α-methylstyrene, vinyltoluene, and other styrene derivatives.

[0061] The content of the styrene compound, preferably styrene, in the raw material monomers of the addition polymerization resin segment is preferably 50% by mass or more, more preferably 70% by mass or more, and even more preferably 80% by mass or more, from the viewpoint of storage stability, and is preferably 95% by mass or less, more preferably 93% by mass or less, and even more preferably 90% by mass or less, from the viewpoint of low-temperature fixability.

[0062] The addition polymerization resin segment may also contain, as a raw material monomer, a (meth)acrylic acid alkyl ester having an alkyl group with 7 or more carbon atoms. Examples of (meth)acrylic acid alkyl esters include 2-ethylhexyl (meth)acrylate, (iso)octyl (meth)acrylate, (iso)decyl (meth)acrylate, and (iso)stearyl (meth)acrylate. It is preferable to use one or more of these. In this specification, "(iso)" refers to both the presence and absence of this group, and indicates normal when this group is not present. Furthermore, "(meth)acrylic acid" refers to acrylic acid, methacrylic acid, or both.

[0063] From the viewpoint of improving the low-temperature fixability of the toner, the number of carbon atoms in the alkyl group of the (meth)acrylic acid alkyl ester used as a raw material monomer for the addition polymerization resin segment is preferably 7 or more, more preferably 8 or more, and preferably 12 or less, more preferably 10 or less. The number of carbon atoms in the alkyl ester refers to the number of carbon atoms derived from the alcohol component constituting the ester.

[0064] The raw material monomers for the addition polymerization resin segment may include raw material monomers other than styrene compounds and (meth)acrylic acid alkyl esters, for example, ethylenically unsaturated monoolefins such as ethylene and propylene; diolefins such as butadiene; halovinyls such as vinyl chloride; vinyl esters such as vinyl acetate and vinyl propionate; ethylenic monocarboxylic acid esters such as dimethylaminoethyl (meth)acrylate; vinyl ethers such as methyl vinyl ether; vinylidene halides such as vinylidene chloride; and N-vinyl compounds such as N-vinylpyrrolidone.

[0065] The addition polymerization reaction of raw material monomers for the addition polymerization resin segment can be carried out by a conventional method in the presence of a polymerization initiator such as dibutyl peroxide or dicumyl peroxide, a chain transfer agent, a crosslinking agent, or the like, in the presence of an organic solvent or without a solvent. The temperature conditions are preferably 110°C or higher, more preferably 140°C or higher, and preferably 200°C or lower, more preferably 170°C or lower.

[0066] When an organic solvent is used in the addition polymerization reaction, xylene, toluene, methyl ethyl ketone, acetone, etc. can be used. The amount of the organic solvent used is preferably 10 parts by mass or more and 50 parts by mass or less per 100 parts by mass of the raw material monomer of the addition polymerization resin segment.

[0067] The bireactive monomer is preferably a compound having at least one functional group selected from the group consisting of hydroxyl, carboxyl, epoxy, primary amino, and secondary amino groups, preferably a hydroxyl and / or carboxyl group, more preferably a carboxyl group, and an ethylenically unsaturated bond in the molecule, more preferably at least one selected from the group consisting of acrylic acid, methacrylic acid, fumaric acid, maleic acid, and maleic anhydride, and even more preferably at least one selected from the group consisting of acrylic acid, methacrylic acid, and fumaric acid from the viewpoint of the reactivity of polycondensation reactions and addition polymerization reactions. However, when used together with a polymerization inhibitor, a polycarboxylic acid compound having an ethylenically unsaturated bond, such as fumaric acid, functions as a raw material monomer for the polyester resin segment. In this case, fumaric acid, etc., is not a bireactive monomer but a raw material monomer for the polyester resin segment.

[0068] The amount of the bireactive monomer used is preferably 1 mol or more, more preferably 2 mol or more, relative to 100 mol of the total alcohol components of the polyester resin segment, from the viewpoint of increasing the dispersibility of the addition polymerization resin segment and the polyester resin segment and improving the durability of the toner, and from the viewpoint of low-temperature fixability, it is preferably 30 mol or less, more preferably 20 mol or less, and even more preferably 10 mol or less. The amount of the bireactive monomer used is preferably 1 part by mass or more, more preferably 2 parts by mass or more, relative to 100 parts by mass of the total raw material monomers for the addition polymerization resin segment, from the viewpoint of improving the dispersibility of the addition polymerization resin segment and the polyester resin segment and improving the durability of the toner, and is preferably 30 parts by mass or less, more preferably 20 parts by mass or less, and even more preferably 10 parts by mass or less, from the viewpoint of low-temperature fixability. Here, the polymerization initiator is included in the total raw material monomers for the addition polymerization resin segment.

[0069] Specifically, the composite resin is preferably produced by the following method: From the viewpoint of improving the charge stability and low-temperature fixability of the toner, the bireactive monomer is preferably subjected to an addition polymerization reaction together with the raw material monomer of the addition polymerization resin segment.

[0070] The composite resin can be produced, for example, by a method including step (X) of polycondensation reaction of raw material monomers for the polyester resin segment and step (Y) of addition polymerization reaction of raw material monomers for the addition polymerization resin segment. (i) Step (Y) may be performed after step (X), (ii) Step (X) may be performed after step (Y), or (iii) Step (X) and Step (Y) may be performed simultaneously.

[0071] In the method (i), after the step (Y), the reaction temperature may be increased again, and if necessary, a raw material monomer of a trivalent or higher polyester resin segment that serves as a crosslinking agent may be added to the reaction system, thereby further promoting the polycondensation reaction of the step (X) or the reaction with the bireactive monomer. Alternatively, a prepolymerized polyester resin may be used instead of the polycondensation reaction in step (X). When steps (X) and (Y) are carried out in parallel, a mixture containing raw material monomers for the addition polymerization resin segment may be added dropwise to a mixture containing raw material monomers for the polyester resin segment to cause the reaction.

[0072] The above methods (i) to (iii) are preferably carried out in the same container.

[0073] The mass ratio of the polyester resin segment to the addition polymerization resin segment in the composite resin is preferably 98 / 2 or less, more preferably 95 / 5 or less, and even more preferably 90 / 10 or less, from the viewpoint of charging stability, and is preferably 60 / 40 or more, more preferably 70 / 30 or more, and even more preferably 75 / 25 or more, from the viewpoint of low-temperature fixability. Here, the mass of the polyester resin segment is the amount of raw material monomers used for the polyester resin segment minus the amount of reaction water (calculated value) dehydrated by the polycondensation reaction, and the amount of the bireactive monomer is included in the amount of raw material monomers for the polyester resin segment. Furthermore, the mass of the addition polymerization resin segment is the total amount of raw material monomers for the addition polymerization resin segment and polymerization initiator.

[0074] The softening point of the amorphous composite resin A is preferably 80°C or higher, more preferably 100°C or higher, from the viewpoint of heat-resistant storage stability, and is preferably 140°C or lower, more preferably 120°C or lower, from the viewpoint of low-temperature fixability.

[0075] The glass transition temperature of the amorphous composite resin A is preferably 40°C or higher, more preferably 50°C or higher, from the viewpoint of heat-resistant storage stability, and is preferably 80°C or lower, more preferably 75°C or lower, and even more preferably 70°C or lower, from the viewpoint of low-temperature fixability.

[0076] The acid value of the amorphous composite resin A is preferably 10 mgKOH / g or more, more preferably 20 mgKOH / g or more, from the viewpoint of low-temperature fixability, and is preferably 40 mgKOH / g or less, more preferably 37 mgKOH / g or less, from the viewpoint of heat-resistant storage stability.

[0077] The content of the amorphous composite resin A in the binder resin is preferably 25% by mass or more, more preferably 30% by mass or more, and even more preferably 35% by mass or more, from the viewpoint of improving the dispersibility of the crystalline polyester resin, and is preferably 98% by mass or less, more preferably 95% by mass or less, and even more preferably 90% by mass or less, from the viewpoint of the crystal recovery of the crystalline polyester resin.

[0078] From the viewpoint of heat-resistant storage stability, the binder resin preferably further contains an amorphous resin B having a softening point higher than that of the amorphous composite resin A.

[0079] Examples of the amorphous resin B include amorphous polyester resin, composite resin having polyester resin and styrene resin, polyamide resin, vinyl resin, epoxy resin, polycarbonate resin, polyurethane resin, etc., with amorphous polyester resin being preferred.

[0080] As with the amorphous composite resin A, the alcohol component of the amorphous polyester resin is preferably an alkylene oxide adduct of bisphenol A represented by formula (I).

[0081] From the viewpoint of low-temperature fixability, the content of the alkylene oxide adduct of bisphenol A in the alcohol component is preferably 70 mol% or more, more preferably 80 mol% or more, even more preferably 90 mol% or more, even more preferably 95 mol% or more, and even more preferably 100 mol%.

[0082] The carboxylic acid component preferably contains an aliphatic dicarboxylic acid compound.

[0083] Examples of the aliphatic dicarboxylic acid compound include aliphatic dicarboxylic acids such as oxalic acid, malonic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, succinic acid which may be substituted with a hydrocarbon group having 1 to 20 carbon atoms, adipic acid, and the like; anhydrides of these acids; and alkyl esters in which the alkyl group has 1 to 3 carbon atoms.

[0084] From the viewpoint of the hydrophilic / hydrophobic balance with the crystalline polyester resin C, the content of the aliphatic dicarboxylic acid compound in the carboxylic acid component is preferably 40 mol % or more, more preferably 45 mol % or more, and 100 mol % or less.

[0085] Examples of the carboxylic acid component other than the aliphatic dicarboxylic acid compound include aromatic dicarboxylic acid compounds and trivalent or higher carboxylic acid compounds.

[0086] Examples of aromatic dicarboxylic acid compounds include phthalic acid, isophthalic acid, terephthalic acid, anhydrides of these acids, and alkyl esters of these acids having 1 to 3 carbon atoms.

[0087] Examples of the trivalent or higher carboxylic acid compound include trimellitic acid, pyromellitic acid, anhydrides of these acids, and alkyl esters of these acids having 1 to 3 carbon atoms.

[0088] From the viewpoint of adjusting the softening point, the content of the trivalent or higher carboxylic acid compound in the carboxylic acid component is preferably 3 mol % or more, more preferably 10 mol % or more, and preferably 40 mol % or less.

[0089] The alcohol component may contain a monohydric alcohol, and the carboxylic acid component may contain a monocarboxylic acid compound, as appropriate.

[0090] The equivalent ratio of the carboxyl groups of the carboxylic acid component to the hydroxyl groups of the alcohol component (COOH groups / OH groups) is preferably 0.6 or more, more preferably 0.7 or more, even more preferably 0.75 or more, and is preferably 1.2 or less, more preferably 1.15 or less.

[0091] The polycondensation reaction conditions of the alcohol component and the carboxylic acid component of the amorphous polyester resin are the same as those of the crystalline polyester resin, except that the suitable reaction temperature is preferably 130°C or higher, more preferably 170°C or higher, and preferably 250°C or lower, more preferably 240°C or lower.

[0092] The softening point of the amorphous resin B is higher than that of the amorphous composite resin A, and the difference in the softening points of the two resins is preferably 10°C or more, more preferably 20°C or more, and preferably 50°C or less, more preferably 30°C or less.

[0093] The softening point of the amorphous resin B is preferably 100°C or higher, more preferably 115°C or higher, and even more preferably 125°C or higher, from the viewpoint of heat-resistant storage stability, and is preferably 150°C or lower, more preferably 145°C or lower, and even more preferably 140°C or lower, from the viewpoint of low-temperature fixability.

[0094] The glass transition temperature of the amorphous resin B is preferably 40°C or higher, more preferably 50°C or higher, from the viewpoint of heat-resistant storage stability, and is preferably 80°C or lower, more preferably 70°C or lower, from the viewpoint of low-temperature fixability.

[0095] The acid value of the amorphous resin B is preferably 10 mgKOH / g or more, more preferably 20 mgKOH / g or more, from the viewpoint of low-temperature fixability, and is preferably 50 mgKOH / g or less, more preferably 40 mgKOH / g or less, from the viewpoint of heat-resistant storage stability.

[0096] The content of the amorphous resin B in the binder resin is preferably 20% by mass or more, more preferably 40% by mass or more, from the viewpoint of heat-resistant storage stability, and is preferably 80% by mass or less, more preferably 70% by mass or less, from the viewpoint of low-temperature fixability.

[0097] When amorphous resin B is contained, the mass ratio of amorphous composite resin A to amorphous resin B is preferably 20 / 80 or more, more preferably 30 / 70 or more, and preferably 60 / 40 or less, more preferably 50 / 50 or less.

[0098] Furthermore, the mass ratio of crystalline polyester resin C to amorphous composite resin A, or, if amorphous resin B is contained, the mass ratio of crystalline polyester resin C to the total amount of amorphous composite resin A and amorphous resin B, is preferably 1 / 99 or more, more preferably 3 / 97 or more, and even more preferably 5 / 95 or more from the viewpoint of low-temperature fixability, and is preferably 40 / 60 or less, more preferably 35 / 65 or less, and even more preferably 30 / 70 or less from the viewpoint of heat-resistant storage stability.

[0099] The total content of crystalline polyester resin C and amorphous composite resin A, or, when amorphous resin B is contained, the total content of crystalline polyester resin C, amorphous composite resin A, and amorphous resin B in the binder resin is preferably 70 mass% or more, more preferably 80 mass% or more, even more preferably 90 mass% or more, even more preferably 95 mass% or more, and even more preferably 100 mass%.

[0100] Other binder resins include vinyl resins such as styrene acrylic resin, epoxy resin, polycarbonate, polyurethane, and composite resins containing two or more of these resins.

[0101] The content of the binder resin in the toner is preferably 30% by mass or more, more preferably 40% by mass or more, even more preferably 45% by mass or more, and is preferably 80% by mass or less, more preferably 70% by mass or less, even more preferably 65% ​​by mass or less.

[0102] Examples of inorganic fine particles include titanium oxide, magnetic powder, silicon dioxide, etc., and among these, titanium oxide, which is widely used as a white colorant, or magnetic powder used in magnetic toner is preferred.

[0103] The titanium oxide particles may be of any of the following crystal types: anatase, rutile, and brookite.

[0104] Commercially available titanium oxide particles include "CR-50-2" and "CR-58" (both manufactured by Ishihara Sangyo Kaisha).

[0105] Examples of magnetic powders include magnetic iron oxides such as magnetite, maghemite, and ferrite, compounds of divalent metals and iron oxides, powders of metals such as iron, cobalt, and nickel, alloys of these metals with metals such as aluminum, cobalt, copper, lead, magnesium, tin, zinc, antimony, beryllium, bismuth, cadmium, calcium, manganese, selenium, titanium, tungsten, and vanadium, and mixtures of these powders.

[0106] The number average primary particle diameter of the inorganic fine particles is preferably 200 nm or more, and preferably 400 nm or less, more preferably 300 nm or less.

[0107] The content of the inorganic fine particles is 50 parts by mass or more, preferably 75 parts by mass or more, more preferably 100 parts by mass or more, relative to 100 parts by mass of the binder resin, and from the viewpoint of pigment dispersibility, is 150 parts by mass or less, preferably 135 parts by mass or less.

[0108] The toner of the present invention may contain additives such as a colorant, a release agent, a charge control agent, a magnetic powder, a flowability improver, a conductivity adjuster, a reinforcing filler such as a fibrous substance, an antioxidant, and a cleaning property improver, in addition to the binder resin and inorganic fine particles.

[0109] The toner of the present invention may contain inorganic fine particles as a colorant, or may contain a colorant other than inorganic fine particles depending on the desired color tone of the toner.

[0110] As the colorant, dyes, pigments, etc. used as toner colorants can be used, such as carbon black, phthalocyanine blue, permanent brown FG, brilliant fast scarlet, pigment red 122, pigment green B, rhodamine-B base, solvent red 49, solvent red 146, solvent blue 35, quinacridone, carmine 6B, isoindoline, and disazo yellow.

[0111] From the viewpoint of improving the image density and low-temperature fixability of the toner, the content of the colorant is preferably 1 part by mass or more, more preferably 2 parts by mass or more, and preferably 40 parts by mass or less, more preferably 20 parts by mass or less, and even more preferably 10 parts by mass or less, relative to 100 parts by mass of the binder resin.

[0112] Examples of the release agent include hydrocarbon waxes such as polypropylene wax, polyethylene wax, polypropylene-polyethylene copolymer wax, microcrystalline wax, paraffin wax, and Fischer-Tropsch wax, and oxides thereof; ester waxes such as carnauba wax, montan wax, and deacidified waxes thereof, and fatty acid ester wax; fatty acid amides, fatty acids, higher alcohols, and fatty acid metal salts, and these may be used alone or in combination of two or more.

[0113] The melting point of the release agent is preferably 60°C or higher, more preferably 70°C or higher, from the viewpoint of toner transferability, and is preferably 160°C or lower, more preferably 140°C or lower, even more preferably 120°C or lower, and even more preferably 110°C or lower, from the viewpoint of low-temperature fixability.

[0114] The content of the release agent is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, and even more preferably 1.5 parts by mass or more, relative to 100 parts by mass of the binder resin, from the viewpoints of the low-temperature fixability and offset resistance of the toner and the dispersibility in the binder resin, and is preferably 10 parts by mass or less, more preferably 8 parts by mass or less, and even more preferably 7 parts by mass or less.

[0115] The charge control agent is not particularly limited, and may contain either a positively chargeable charge control agent or a negatively chargeable charge control agent.

[0116] Positively chargeable charge control agents include nigrosine dyes such as "Nigrosine Base EX," "Oil Black BS," "Oil Black SO," "Bontron N-01," "Bontron N-04," "Bontron N-07," "Bontron N-09," and "Bontron N-11" (all manufactured by Orient Chemical Industries Co., Ltd.); triphenylmethane dyes containing a tertiary amine as a side chain; quaternary ammonium salt compounds such as "Bontron P-51" (manufactured by Orient Chemical Industries Co., Ltd.), cetyltrimethylammonium bromide, and "COPY CHARGE PX Examples of suitable resins include "VP435" (manufactured by Clariant), etc.; polyamine resins, such as "AFP-B" (manufactured by Orient Chemical Industries Co., Ltd.); imidazole derivatives, such as "PLZ-2001" and "PLZ-8001" (both manufactured by Shikoku Chemical Industry Co., Ltd.); and styrene-acrylic resins, such as "FCA-2521N," "FCA-701PT," and "FCA-201-PS" (manufactured by Fujikura Chemical Co., Ltd.).

[0117] Examples of negatively chargeable charge control agents include metal-containing azo dyes such as "Balifast Black 3804," "Bontron S-31," "Bontron S-32," "Bontron S-34," and "Bontron S-36" (all manufactured by Orient Chemical Industries, Ltd.), "Eisenspiron Black TRH," and "T-77" (manufactured by Hodogaya Chemical Co., Ltd.); metal compounds of benzilic acid compounds such as "LR-147" and "LR-297" (manufactured by Nippon Carlit Co., Ltd.); metal compounds of salicylic acid compounds such as "Bontron E-81," "Bontron E-84," "Bontron E-88," and "Bontron E-304" (all manufactured by Orient Chemical Industries, Ltd.), and "TN-105" (manufactured by Hodogaya Chemical Co., Ltd.); copper phthalocyanine dyes; and quaternary ammonium salts such as "COPY CHARGE NX VP434 (manufactured by Clariant), nitroimidazole derivatives, etc.; organometallic compounds, etc.

[0118] From the viewpoint of the charging stability of the toner, the content of the charge control agent is preferably 0.01 parts by mass or more, more preferably 0.2 parts by mass or more, and preferably 10 parts by mass or less, more preferably 5 parts by mass or less, even more preferably 3 parts by mass or less, and even more preferably 2 parts by mass or less, relative to 100 parts by mass of the binder resin.

[0119] The toner of the present invention may be obtained by any conventionally known method such as a melt-kneading method, an emulsion phase inversion method, or a polymerization method, but from the viewpoint of productivity and colorant dispersibility, a pulverized toner obtained by a melt-kneading method is preferred. In the case of a pulverized toner obtained by a melt-kneading method, for example, raw materials such as a binder resin and inorganic fine particles, and optionally a colorant, a release agent, and a charge control agent, are uniformly mixed in a mixer such as a Henschel mixer, and then melt-kneaded in an internal kneader, a single-screw or twin-screw extruder, an open-roll kneader, or the like, followed by cooling, pulverization, and classification to produce the toner. The inorganic fine particles are not added externally to the toner particles, but are added internally together with the binder resin, etc.

[0120] In order to improve the transferability of the toner of the present invention, it is preferable to use an external additive. Examples of the external additive include inorganic fine particles such as silica, alumina, titania, zirconia, tin oxide, and zinc oxide, and organic fine particles such as resin particles such as melamine-based resin fine particles and polytetrafluoroethylene resin fine particles, and two or more of these may be used in combination. Among these, silica is preferred, and from the viewpoint of the transferability of the toner, hydrophobic silica that has been subjected to a hydrophobic treatment is more preferred.

[0121] Examples of hydrophobic treatment agents for hydrophobizing the surfaces of silica particles include hexamethyldisilazane (HMDS), dimethyldichlorosilane (DMDS), silicone oil, octyltriethoxysilane (OTES), and methyltriethoxysilane.

[0122] From the viewpoint of the chargeability, fluidity, and transferability of the toner, the average particle diameter of the external additive is preferably 10 nm or more, more preferably 15 nm or more, and is preferably 250 nm or less, more preferably 200 nm or less, and even more preferably 90 nm or less.

[0123] From the viewpoint of the chargeability, fluidity, and transferability of the toner, the content of the external additive is preferably 0.05 parts by mass or more, more preferably 0.1 parts by mass or more, and even more preferably 0.3 parts by mass or more, relative to 100 parts by mass of the toner particles before treatment with the external additive, and is preferably 5 parts by mass or less, and more preferably 3 parts by mass or less.

[0124] The volume median particle size (D 50 ) is preferably 3 μm or more, more preferably 4 μm or more, and is preferably 15 μm or less, more preferably 10 μm or less. 50 ) means the particle size at which the cumulative volume frequency calculated by volume fraction is 50% starting from the smallest particle size. In addition, when the toner is treated with an external additive, the volume median particle size of the toner particles before treatment with the external additive is taken as the volume median particle size of the toner.

[0125] The toner of the present invention can be used as a toner for one-component development as it is, or as a toner for two-component development mixed with a carrier, in an image forming apparatus of a one-component development system or a two-component development system, respectively. [Example]

[0126] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. Physical properties of resins and the like can be measured by the following methods.

[0127] [Softening point of resin] Using a flow tester "CFT-500D" (Shimadzu Corporation), 1 g of sample is heated at a temperature increase rate of 6°C / min while applying a load of 1.96 MPa with the plunger, and extruding it from a nozzle 1 mm in diameter and 1 mm in length. The plunger depression distance of the flow tester is plotted against the temperature, and the temperature at which half of the sample flows out is taken as the softening point.

[0128] [Maximum endothermic peak temperature of resin] Using a differential scanning calorimeter "Q-100" (manufactured by TA Instruments Japan Co., Ltd.), 0.01 to 0.02 g of sample is weighed into an aluminum pan, cooled from room temperature (25°C) to 0°C at a rate of 10°C / min, and maintained at 0°C for 1 minute. Then, measurements are performed at a rate of 10°C / min. The temperature of the peak with the largest peak area among the observed endothermic peaks is taken as the maximum endothermic peak temperature.

[0129] [Glass transition temperature of resin] Using a differential scanning calorimeter "Q-100" (TA Instruments Japan), 0.01-0.02 g of sample is weighed into an aluminum pan, heated to 200°C, and cooled to 0°C at a rate of 10°C / min. The sample is then heated at a rate of 10°C / min, and the endothermic peak is measured. The glass transition temperature is the temperature at the intersection of an extension of the baseline below the maximum endothermic peak temperature and a tangent line showing the maximum slope from the rising part of the peak to the peak apex.

[0130] [Acid value of resin] Measurements are made based on the method of JIS K 0070:1992, except that the measurement solvent is changed from the ethanol and ether mixture specified in JIS K 0070 to a mixture of acetone and toluene (acetone:toluene = 1:1 (volume ratio)) for amorphous resins, and to a mixture of chloroform and dimethylformamide (chloroform:dimethylformamide = 7:3 (volume ratio)) for crystalline resins.

[0131] [Number average primary particle diameter of inorganic fine particles] The particle sizes (average values ​​of major and minor diameters) of 500 particles are measured from a scanning electron microscope (SEM) photograph, and the number average value is calculated.

[0132] [Melting point of release agent] Using a differential scanning calorimeter "DSC Q20" (TA Instruments Japan), 0.01-0.02 g of sample is weighed into an aluminum pan, heated to 200°C at a rate of 10°C / min, and cooled to -10°C at a rate of 5°C / min. The sample is then heated to 180°C at a rate of 10°C / min and measured, with the maximum endothermic peak temperature being the melting point.

[0133] [Average particle size of external additives] The average particle size refers to the number-average particle size, and is calculated by measuring the particle sizes (average values ​​of major and minor axes) of 500 particles in a scanning electron microscope (SEM) photograph and averaging these values ​​by number.

[0134] [Volume median particle size of toner (D 50 ) Measuring instrument: Coulter Multisizer III (manufactured by Beckman Coulter, Inc.) Aperture diameter: 100 μm Analysis software: Multisizer III version 3.51 (Beckman Coulter, Inc.) Electrolyte: "Isoton (registered trademark) II" (manufactured by Beckman Coulter, Inc.) Dispersion: Polyoxyethylene lauryl ether "Emulgen (registered trademark) 109P" (manufactured by Kao Corporation, HLB (Griffin) = 13.6) dissolved in the electrolyte to adjust the concentration to 5% by mass Dispersion conditions: 10 mg of the measurement sample was added to 5 mL of the dispersion, and the mixture was dispersed for 1 minute using an ultrasonic disperser (machine name: US-1 manufactured by SND Corporation, output: 80 W). 25 mL of electrolyte was then added, and the mixture was further dispersed for 1 minute using the ultrasonic disperser to prepare a sample dispersion. Measurement conditions: The sample dispersion was added to 100 mL of the electrolyte 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, and the volume median particle size (D50 ) is found.

[0135] Preparation Example 1 of Alkenyl Succinic Anhydride (1) Propylene tetramer (manufactured by Nippon Oil Corporation, trade name: "Light Tetramer") was fractionally distilled at a heating condition of 183 to 208°C to obtain an alkylene compound (a). The obtained alkylene compound (a) had 40 peaks in gas chromatography mass spectrometry, which will be described later. The distribution of the alkylene compound was measured according to the analysis of alkylene compound A by mass spectrometry gas chromatography in JP 2014-013384 A, and the C9H 18 :0.5% by mass, C 10 H 20 :4% by mass, C 11 H 22 :20% by mass, C 12 H 24 :66% by mass, C 13 H 26 :9% by mass, C 14 H 28 : 0.5% by mass (6 peaks corresponding to alkylene compounds having 9 to 14 carbon atoms).

[0136] (2) A 1-liter autoclave manufactured by Nitto Koatsu Co., Ltd. was charged with 542.4 g of alkylene compound (a), 157.2 g of maleic anhydride, 0.4 g of the antioxidant "Cherex-O" (triisooctyl phosphite manufactured by SC Organic Chemical Co., Ltd.), and 0.1 g of butylhydroquinone as a polymerization inhibitor. Pressure and nitrogen substitution (0.2 MPaG) were repeated three times. After stirring was initiated at 60°C, the mixture was heated to 230°C over one hour and reacted for six hours. The pressure at the time the reaction temperature was reached was 0.3 MPaG. After the reaction was completed, the mixture was cooled to 80°C, returned to atmospheric pressure (101.3 kPa), and transferred to a 1-liter four-neck flask. The mixture was heated to 180°C with stirring, and the remaining alkylene compound was distilled off at 1.3 kPa over one hour. Subsequently, the mixture was cooled to room temperature (25°C) and then returned to normal pressure (101.3 kPa) to obtain 406.1 g of the target product, alkenyl succinic anhydride A. The average molecular weight of alkenyl succinic anhydride A calculated from the acid value was 268.

[0137] Resin manufacturing example 1 The raw material monomers and esterification catalyst for the polyester resin segment shown in Table 1 were placed in a 10-liter four-neck flask equipped with a dehydration tube with a nitrogen inlet, a stirrer, and a thermocouple. The flask was heated to 160°C in a mantle heater under a nitrogen atmosphere. A mixture of the raw material monomers for the addition polymerization resin segment, the bireactive monomer, and a polymerization initiator was then added dropwise over one hour to allow polymerization. The temperature was then raised to 200°C and the reaction was allowed to mature for one hour, producing the addition polymerization resin segment in the reaction system. The temperature was then raised every hour to 230°C, and after confirming that all solid monomers had melted and reacted, the pressure was reduced to 8.0 KPa and dehydration condensation was allowed to proceed for one hour. The reaction was then continued at 210°C and 10 kPa until the softening point shown in Table 1 was reached, yielding an amorphous composite resin (Resin A).

[0138] [Table 1]

[0139] Resin manufacturing example 2 The alcohol components shown in Table 2, carboxylic acid components other than trimellitic anhydride, an esterification catalyst, and a polymerization inhibitor were placed in a 10-liter four-neck flask equipped with a dehydration tube with a nitrogen inlet tube, a stirrer, and a thermocouple, and the temperature was raised to 230°C in a mantle heater in a nitrogen atmosphere, followed by polycondensation for 7 hours. The temperature was then lowered to 200°C, trimellitic anhydride was added, and the temperature was then raised to 210°C to carry out the polycondensation reaction until the softening point reached the temperature shown in Table 2, yielding an amorphous polyester resin (Resin B).

[0140] [Table 2]

[0141] Resin manufacturing example 3 The alcohol component, carboxylic acid component, and esterification catalyst shown in Table 3 were placed in a 10-liter four-neck flask equipped with a dehydration tube equipped with a nitrogen inlet tube, a stirrer, and a thermocouple, and the temperature was raised to 200°C over 8 hours in a mantle heater under a nitrogen atmosphere. Thereafter, the reaction was continued at 8.0 kPa until the softening point shown in Table 3 was reached, yielding crystalline polyester resins (resins C1 to C7).

[0142] [Table 3]

[0143] Examples 1 to 6 and Comparative Examples 1 to 5 100 parts by mass of the binder resin shown in Table 4, inorganic fine particles (titanium oxide: "CR-50-2" (Ishihara Sangyo Kaisha, Ltd., number average primary particle diameter: 250 nm)), 5 parts by mass of charge control agent "FCA-2521NJ" (Fujikura Kasei Co., Ltd.), and 1.5 parts by mass of release agent "HNP-9" (Nippon Seiro Co., Ltd., paraffin wax, melting point: 79°C) were premixed using a Henschel mixer for 1 minute, and then melt-kneaded using a twin-screw extruder "PCM-30" (Ikegai Iron Works Co., Ltd.). The operating conditions of the twin-screw extruder were a barrel setting temperature of 100°C, a shaft rotation speed of 200 r / min (circumferential speed of shaft rotation: 0.30 m / sec), and a mixture feed rate of 10 kg / h. The resulting resin kneaded product was cooled and the volume median particle diameter (D ) was measured using an IDS pulverizer / classifier (Nippon Pneumatic Co., Ltd.). 50 The particles were pulverized and classified so that the particle size became 7.0 μm, thereby obtaining toner particles.

[0144] To 100 parts by mass of the obtained toner particles, 1 part by mass of external additive "Aerosil R-972" (hydrophobic silica, manufactured by Nippon Aerosil Co., Ltd., hydrophobic treatment agent: DMDS, average particle diameter: 16 nm) and 2 parts by mass of "RY-50" (manufactured by Nippon Aerosil Co., Ltd., hydrophobic treatment agent: silicone oil, average particle diameter: 40 nm) were added, and the mixture was mixed in a Henschel mixer at 2300 r / min for 3 minutes to perform external additive treatment and obtain a toner.

[0145] Examples 7 to 9 and Comparative Example 6 Toner particles were obtained in the same manner as in Example 1 using 100 parts by mass of the binder resin shown in Table 4 and inorganic fine particles (magnetic powder (magnetite): EPT-1002 (manufactured by Toda Kogyo Co., Ltd., number average primary particle diameter: 230 nm)), 2 parts by mass of carbon black "Mogul-L" (manufactured by Cabot Corporation), 1 part by mass of charge control agent "T-77" (manufactured by Hodogaya Chemical Co., Ltd.), and 1.5 parts by mass of release agent "HNP-9" (manufactured by Nippon Seiro Co., Ltd., paraffin wax, melting point: 79°C), and the obtained toner was obtained by mixing the toner with external additives.

[0146] Test Example 1 [Image curl suppression] The toner was installed in a non-magnetic single-component developing device "Monochrome LED Printer B432dnw" (manufactured by Oki Electric Co., Ltd.), and the toner adhesion amount was 0.70±0.05mg / cm 2 The sheet was adjusted to the desired thickness and a 190 mm x 2.0 cm solid image was printed on "J Paper" (manufactured by Fuji Xerox Co., Ltd.). Ten sheets of the solid image were printed on one side and placed on a flat surface with the printed side facing down. After leaving the sheet to stand for 24 hours in an environment of 23°C and 50% relative humidity, the maximum height from the flat surface to the paper was measured as the amount of curl. The results are shown in Table 4.

[0147] Test Example 2 [Heat-resistant storage stability] 5 g of toner was placed in a 20 mL polypropylene container. The container containing the toner was placed in a thermo-hygrostat chamber at 50°C and a relative humidity of 60%, and left for 48 hours with the lid of the container open. The degree of aggregation of the toner after leaving it was measured using the following method and used as an index of heat-resistant storage stability. The results are shown in Table 4. The smaller this value, the better the heat-resistant storage stability. The degree of aggregation is preferably 40% or less, and more preferably 20% or less.

[0148] <Cohesion degree> The degree of cohesion is measured using a powder tester (manufactured by Hosokawa Micron Corporation). Stack sieves with openings of 150μm, 75μm, and 45μm, place 5g of toner on top, and vibrate at a vibration amplitude of 1mm for 60 seconds. After vibration, measure the amount of toner remaining on the sieve and calculate the degree of cohesion using the following formula.

[0149]

number

[0150] [Table 4]

[0151] From the above results, it can be seen that, in comparison with Comparative Examples 1 to 6, Examples 1 to 9 suppressed image curling and also had good heat-resistant storage stability. In particular, in Comparative Examples 1 and 6, which have a low content of inorganic fine particles, image curling hardly occurs, and it is clear that the occurrence of curling is a problem specific to toners with a high content of inorganic fine particles. [Industrial Applicability]

[0152] The toner for developing electrostatic images of the present invention is suitably used for developing latent images formed in electrophotography, electrostatic recording, electrostatic printing and the like.

Claims

1. 1. An electrophotographic toner containing a binder resin and inorganic fine particles, wherein the binder resin contains a crystalline polyester resin C which is a polycondensation product of an alcohol component containing ethylene glycol and a carboxylic acid component which contains a dicarboxylic acid compound having 6 to 16 carbon atoms; and an amorphous composite resin A which contains a polyester resin segment, an addition polymerization resin segment which is an addition polymerization product of a raw material monomer containing a styrene compound, and a structural unit derived from a bireactive monomer in which the polyester resin segment and the addition polymerization resin segment are bonded via a covalent bond, and the inorganic fine particles are titanium oxide, and the content of the inorganic fine particles is 50 to 150 parts by mass per 100 parts by mass of the binder resin.

2. An electrophotographic toner containing a binder resin and inorganic fine particles, wherein the binder resin contains a crystalline polyester resin C which is a polycondensation product of an alcohol component containing ethylene glycol and a carboxylic acid component containing a dicarboxylic acid compound having 6 to 16 carbon atoms, a polyester resin segment, an addition polymerization resin segment which is an addition polymerization product of raw material monomers containing a styrene compound, and an amorphous composite resin A which contains a structural unit derived from a bireactive monomer in which the polyester resin segment and the addition polymerization resin segment are bonded via a covalent bond, wherein the bireactive monomer is a compound having a carboxy group and an ethylenically unsaturated bond in the molecule, the inorganic fine particles are magnetite, and the content of the inorganic fine particles is 50 to 150 parts by mass per 100 parts by mass of the binder resin.

3. 3. The toner for developing electrostatic images according to claim 1, wherein the content of the amorphous composite resin A in the binder resin is 25% by mass or more and 98% by mass or less.

4. 3. The toner for developing electrostatic images according to claim 1, wherein the content of the crystalline polyester resin C in the binder resin is 25% by mass or less.

5. 3. The toner for developing electrostatic images according to claim 1, wherein the number average primary particle diameter of the inorganic fine particles is 200 nm or more and 400 nm or less.

Images