Toner for development of electrostatic charge images

Abstract

This toner for development of electrostatic charge images contains a crystalline polyester resin C and an amorphous polyester resin A. The crystalline polyester resin C is a polycondensate of: an alcohol component containing 70 mol% or more of ethylene glycol; and a carboxylic acid component containing an aliphatic dicarboxylic acid-based compound. The alcohol component and / or the carboxylic acid component contains a monofunctional monomer. The amorphous polyester resin A is a polycondensate of: an alcohol component; a carboxylic acid component; and polyethylene terephthalate. A toner for development of electrostatic charge images according to the present invention is suitably used for development and the like of latent images formed through electrophotography, electrostatic recording, electrostatic printing, etc.

Description

Toner for developing electrostatic images

[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.

[0002] A toner for developing electrostatic images has been proposed that contains a binder resin that combines an amorphous polyester resin incorporating polyethylene terephthalate and a crystalline polyester resin that uses ethylene glycol as an alcohol component, both of which have high affinity with each other (see Patent Document 1).

[0003] On the other hand, a polyester resin using a monovalent long-chain aliphatic monomer as a raw material monomer effective in reducing moisture absorption has been proposed (see Patent Document 2).

[0004] JP 2019-66536 A JP 2021-189196 A

[0005] The present invention relates to a toner for developing electrostatic images, which contains a crystalline polyester resin C and an amorphous polyester resin A, in which the crystalline polyester resin C is a polycondensate of an alcohol component containing 70 mol % or more of ethylene glycol and a carboxylic acid component containing an aliphatic dicarboxylic acid compound, and the alcohol component and / or the carboxylic acid component contains a monofunctional monomer, and the amorphous polyester resin A is a polycondensate of the alcohol component, the carboxylic acid component, and polyethylene terephthalate. Detailed Description of the Invention

[0006] Crystalline polyester resins are used to improve the low-temperature fixability of toners, but if the dispersion state in the toner is not sufficiently controlled, the charging stability is likely to be affected. Furthermore, in recent years, in situations where stricter heat resistance is required, it is also required to ensure pressurized storage stability.

[0007] The present invention relates to a toner for developing electrostatic images, which has excellent charge stability and storage stability under pressure.

[0008] The toner for developing electrostatic images of the present invention exhibits excellent effects in terms of charge stability and storage stability under pressure.

[0009] The electrostatic image developing toner of the present invention is characterized in that it contains a crystalline polyester resin (crystalline polyester resin C) using ethylene glycol and a monofunctional monomer, and an amorphous polyester resin (amorphous polyester resin A) using polyethylene terephthalate (PET). The reason why the electrostatic image developing toner of the present invention has excellent charge stability and pressurized storage stability is not clear, but is presumed to be as follows.

[0010] In crystalline polyester resins containing ethylene glycol as the main alcohol component and a monofunctional monomer-derived component, the monofunctional monomer-derived component forms a terminal structure of the resin and is more hydrophobic than the terminals of carboxyl and hydroxyl groups. On the other hand, in amorphous polyester resins obtained using PET, during the polycondensation reaction of the alcohol component, carboxylic acid component, and PET, the PET undergoes depolymerization and is incorporated into the polyester resin chain through a transesterification reaction, but is not completely randomized and exists in the resin as units of a certain length that can be called PET segments. The high affinity between these PET segments and the crystalline polyester resin containing ethylene glycol as the main alcohol component improves the dispersibility of the crystalline polyester resin in the amorphous polyester resin and promotes crystallization. As a result, the toner exhibits good storage stability even when stored under pressure, and the hydrophobic terminals derived from the monofunctional monomer are oriented toward the outside from the domains of the crystalline polyester resin with improved dispersibility present near the surface of the toner particles, thereby reducing the hygroscopicity of the toner and improving its charging stability.

[0011] The crystalline polyester resin C is a polycondensate of an alcohol component containing ethylene glycol as a main component and a carboxylic acid component containing an aliphatic dicarboxylic acid compound.

[0012] The content of ethylene glycol in the alcohol component is 70 mol% or more, preferably 80 mol% or more, more preferably 90 mol% or more, and even more preferably 95 mol% or more, and is 100 mol% or less. When the alcohol component contains a monoalcohol, the content is preferably 98 mol% or less, more preferably 95 mol% or less.

[0013] Examples of other alcohol components 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; alkylene oxide adducts of bisphenol A; aromatic diols such as bisphenol A; hydrogenated bisphenol A; sorbitol, pentaerythritol, glycerin; and tri- or higher hydric alcohols such as trimethylolpropane.

[0014] Examples of aliphatic dicarboxylic acid compounds include succinic acid (number of carbon atoms: 4), fumaric acid (number of carbon atoms: 4), 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 acids having an alkyl group or an alkenyl group on the side chain, anhydrides of these acids, and alkyl esters of these acids having from 1 to 3 carbon atoms. Here, when the aliphatic dicarboxylic acid compound is an alkyl ester, the number of carbon atoms of the alkyl group is not included in the above carbon number.

[0015] From the viewpoint of hydrophobicity, the carbon number of the aliphatic dicarboxylic acid compound is preferably 4 or more, more preferably 8 or more, even more preferably 10 or more, and even more preferably 12 or more, and from the viewpoint of low-temperature fixability, the carbon number is preferably 16 or less, more preferably 14 or less.

[0016] The aliphatic dicarboxylic acid compound may be a saturated aliphatic dicarboxylic acid compound or an unsaturated aliphatic dicarboxylic acid compound, but from the viewpoint of storage stability under pressure, it is preferably a saturated aliphatic dicarboxylic acid compound.

[0017] From the viewpoint of pressurized storage stability, the content of the aliphatic dicarboxylic acid compound in the carboxylic acid component is preferably 80 mol% or more, more preferably 90 mol% or more, even more preferably 95 mol% or more, and 100 mol% or less. When the carboxylic acid component contains a monocarboxylic acid compound, the content is preferably 98 mol% or less, more preferably 95 mol% or less.

[0018] Examples of other carboxylic acid components include aromatic dicarboxylic acid compounds such as phthalic acid, isophthalic acid, and terephthalic acid, and trivalent or higher carboxylic acid compounds such as trimellitic acid and pyromellitic acid.

[0019] Furthermore, the alcohol component and / or the carboxylic acid component of the crystalline polyester resin C contains a monofunctional monomer.

[0020] Examples of monofunctional monomers contained in the alcohol component include aliphatic monoalcohols such as capryl alcohol, capric alcohol, lauryl alcohol, myristyl alcohol, palmityl alcohol, stearyl alcohol, and behenyl alcohol.

[0021] Examples of the monofunctional monomer contained in the carboxylic acid component include aliphatic monocarboxylic acids such as caproic acid, 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.

[0022] From the viewpoint of improving hydrophobicity, the monofunctional monomer preferably contains an aliphatic monocarboxylic acid compound and / or an aliphatic monoalcohol.

[0023] The number of carbon atoms of the aliphatic monoalcohol is preferably 6 or more, more preferably 9 or more, even more preferably 10 or more, and even more preferably 12 or more, from the viewpoint of hydrophobicity, and is preferably 24 or less, more preferably 23 or less, and even more preferably 22 or less, from the viewpoint of low-temperature fixability.

[0024] From the viewpoint of hydrophobicity, the carbon number of the aliphatic monocarboxylic acid compound is preferably 6 or more, more preferably 9 or more, and even more preferably 10 or more, and from the viewpoint of low-temperature fixability, it is preferably 24 or less, more preferably 23 or less, and even more preferably 22 or less. When the aliphatic monocarboxylic acid compound is an alkyl ester, the carbon number of the alkyl group is not included in the above carbon number.

[0025] The content of the monofunctional monomer is preferably 2 mol% or more, more preferably 3 mol% or more, and even more preferably 5 mol% or more, of the total amount of the alcohol component and the carboxylic acid component, and from the viewpoint of pressurized storage stability, it is preferably 30 mol% or less, more preferably 25 mol% or less, and even more preferably 20 mol% or less.

[0026] In this specification, macromonomers and hydroxycarboxylic acids are not included in the alcohol component and carboxylic acid component.

[0027] 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, from the viewpoint of pressurized storage stability, and is preferably 1.2 or less, more preferably 1.1 or less, from the viewpoint of low-temperature fixability.

[0028] The 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 a co-catalyst, a polymerization inhibitor, etc., at a temperature preferably of 120°C or higher and 230°C or lower.

[0029] Examples of the esterification catalyst include tin compounds such as dibutyltin oxide and tin(II) 2-ethylhexanoate, and titanium compounds such as titanium diisopropoxybis(triethanolaminate) and titanium dihydroxybis(triethanolaminate). 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 total of the alcohol component and the carboxylic acid component. Examples of the co-catalyst for the esterification catalyst include gallic acid. The amount of the co-catalyst 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 total of the alcohol component and the carboxylic acid component. 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, relative to 100 parts by mass of the total amount of the alcohol component and the carboxylic acid component.

[0030] 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 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.

[0031] 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 pressurized storage stability, and is preferably 120°C or lower, more preferably 110°C or lower, from the viewpoint of low-temperature fixability.

[0032] The crystallinity of a resin is expressed by the crystallinity index, defined as the ratio of the softening point to the maximum endothermic peak temperature measured by a differential scanning calorimeter, i.e., the value [softening point / maximum endothermic peak temperature]. Crystalline resins have a crystallinity index of 0.6 or higher, preferably 0.7 or higher, more preferably 0.9 or higher, and 1.4 or lower, preferably 1.2 or lower, more preferably 1.1 or lower. On the other hand, amorphous resins have no observed endothermic peak, or, if observed, have a crystallinity index of greater than 1.4, preferably greater than 1.5, more preferably 1.6 or higher, or less than 0.6, preferably 0.5 or lower. The crystallinity of a resin can be adjusted by the type and ratio of raw material monomers, 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.

[0033] 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 pressurized storage stability, and is preferably 130°C or lower, more preferably 120°C or lower, from the viewpoint of low-temperature fixability.

[0034] 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 charging stability, and is preferably 20 mgKOH / g or less, more preferably 15 mgKOH / g or less, from the viewpoint of pressurized storage stability.

[0035] The content of crystalline polyester resin C is preferably 3% by mass or more, more preferably 5% by mass or more, and even more preferably 8% by mass or more, of the total amount of crystalline polyester resin C and amorphous polyester resin A, from the viewpoints of low-temperature fixability and pressurized storage stability, and is preferably 30% by mass or less, more preferably 25% by mass or less, and even more preferably 20% by mass or less, from the viewpoint of pressurized storage stability.

[0036] The amorphous polyester resin A is a polycondensation product of an alcohol component, a carboxylic acid component, and PET.

[0037] From the viewpoint of pressurized storage stability and charging stability, the alcohol component preferably contains an aliphatic diol having 3 to 6 carbon atoms.

[0038] Examples of aliphatic diols having 3 to 6 carbon atoms include 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 2,3-butanediol, 1,5-pentanediol, neopentyl glycol, 1,6-hexanediol, etc. Among these, neopentyl glycol is preferred from the viewpoint of storage stability under pressure.

[0039] From the viewpoint of storage stability under pressure, the content of the aliphatic diol having 3 to 6 carbon atoms in the alcohol component is preferably 30 mol % or more, more preferably 40 mol % or more, and even more preferably 50 mol % or more, and 100 mol % or less, and when the alcohol component contains a trihydric or higher alcohol, it is preferably 98 mol % or less, more preferably 90 mol % or less, provided that the alcohol component here does not include the ethylene glycol unit of PET.

[0040] Examples of other alcohol components include aliphatic diols having 7 or more carbon atoms, alkylene oxide adducts of bisphenol A, aromatic diols such as bisphenol A, hydrogenated bisphenol A, trihydric or higher alcohols such as sorbitol, pentaerythritol, glycerin, and trimethylolpropane.

[0041] From the viewpoint of charging stability, the carboxylic acid component preferably contains an aromatic dicarboxylic acid compound.

[0042] 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.

[0043] The content of the aromatic dicarboxylic acid compound in the carboxylic acid component is preferably 70 mol% or more, more preferably 80 mol% or more, even more preferably 90 mol% or more, and still more preferably 95 mol% or more, and is 100 mol% or less, and when the carboxylic acid component contains a trivalent or higher carboxylic acid compound, it is preferably 98 mol% or less, more preferably 90 mol% or less, provided that the carboxylic acid component does not include the terephthalic acid unit contained in PET.

[0044] Examples of carboxylic acid components other than aromatic dicarboxylic acid compounds include fumaric acid, maleic acid, succinic acid, succinic acid derivatives substituted with a hydrocarbon group, aliphatic dicarboxylic acids such as glutaric acid, adipic acid, and sebacic acid, trivalent or higher carboxylic acids such as trimellitic acid and pyromellitic acid, anhydrides of these acids, and alkyl esters of these acids having 1 to 3 carbon atoms.

[0045] From the viewpoint of adjusting the softening point, trivalent or higher hydric raw material monomers may be used for the alcohol component and / or carboxylic acid component of the amorphous polyester resin A. In this case, from the viewpoint of charge stability, it is preferable to use a trivalent or higher hydric alcohol, preferably glycerin or trimethylolpropane, more preferably glycerin. The content of the trivalent or higher hydric raw material monomer is preferably 2 mol% or more, more preferably 4 mol% or more, and preferably 25 mol% or less, more preferably 20 mol% or less, of the total amount of the alcohol component, carboxylic acid component, and PET.

[0046] The alcohol component may appropriately contain a monohydric alcohol, and the carboxylic acid component may appropriately contain a monocarboxylic acid compound.

[0047] PET is produced by a polycondensation reaction between an alcohol component and a carboxylic acid component, and / or by depolymerization of a portion of PET. Ethylene glycol and terephthalic acid are produced as raw material monomers in the polycondensation reaction and then incorporated into a polyester resin. PET is an equimolar polycondensate of ethylene glycol and terephthalic acid, and the ethylene glycol and terephthalic acid that make up PET are considered to be the alcohol component and the carboxylic acid component, respectively.

[0048] The PET may be new virgin PET or recycled PET. Recycled PET is obtained by collecting used PET, washing it as necessary, separating it from other materials, and then pulverizing it, decomposing the pulverized material into monomer units, and using these as raw materials for resynthesis.

[0049] In the present invention, the PET preferably has a relatively low IV value, i.e., a low molecular weight, compared to conventionally used PET. By introducing a PET with a low IV value (low molecular weight) into the polyester resin, depolymerization of the PET proceeds more uniformly.

[0050] From the above viewpoints, the IV value of PET is preferably 0.40 or more, more preferably 0.45 or more, even more preferably 0.50 or more, and even more preferably 0.55 or more. From the viewpoints of low-temperature fixability and uniform depolymerization, it is preferably 0.85 or less, more preferably 0.80 or less, even more preferably 0.75 or less, even more preferably 0.70 or less, and even more preferably 0.65 or less. The IV value is an intrinsic viscosity and serves as an index of molecular weight. The IV value of PET can be adjusted by the polycondensation time, etc.

[0051] Commercially available PET products having an IV value of 0.40 to 0.85 include RAMAPET L1 (manufactured by Indorama Ventures, IV value: 0.60), RAMAPET BF3067 (manufactured by Indorama Ventures, IV value: 0.65), RAMAPET N2G (manufactured by Indorama Ventures, IV value: 0.75), TRN-NTJ (manufactured by Teijin Limited, IV value: 0.53), TRN-RTJC (manufactured by Teijin Limited, IV value: 0.64), RAMAPET S1 (manufactured by Indorama Ventures, IV value: 0.84), and UK-31 (manufactured by Utsumi Recycle Systems Co., Ltd., IV value: 0.67).

[0052] The content of the low IV PET is preferably 90% by mass or more, more preferably 95% by mass or more, even more preferably 98% by mass or more, and still more preferably 100% by mass, of the total amount of PET used in polycondensation.

[0053] From the viewpoint of pressurized storage stability, the PET content is preferably 5 mol% or more, more preferably 10 mol% or more, even more preferably 15 mol% or more, and even more preferably 20 mol% or more, based on the total amount of the alcohol component, the carboxylic acid component, and the PET, and is preferably 75 mol% or less, more preferably 70 mol% or less, and even more preferably 65 mol% or less. When the amorphous polyester resin A is composed of two or more resins, the weighted average of the PET contents of each resin is taken as the PET content of the amorphous polyester resin A. Note that, since PET is a polycondensation product of ethylene glycol with terephthalic acid, dimethyl terephthalate, or the like, it is calculated by counting terephthalic acid-ethylene glycol units (Mw: 192) as 1 mole. Therefore, the number of moles of PET = the number of moles of ethylene glycol units = the number of moles of terephthalic acid units.

[0054] The equivalent ratio (COOH groups / OH groups) of the carboxylic acid component (including terephthalic acid units in PET) to the alcohol component (including ethylene glycol units in PET) is preferably 0.6 or more, more preferably 0.7 or more, even more preferably 0.8 or more, and is preferably 1.3 or less, more preferably 1.2 or less.

[0055] The polycondensation reaction conditions of the alcohol component, carboxylic acid component, and PET for the amorphous polyester resin are the same as those for 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.

[0056] The softening point of the amorphous polyester resin A is preferably 70°C or higher, more preferably 90°C or higher, and even more preferably 100°C or higher from the viewpoint of charging stability, and is preferably 170°C or lower, more preferably 160°C or lower, and even more preferably 150°C or lower from the viewpoint of low-temperature fixability.

[0057] From the viewpoint of low-temperature fixability and fixation width, the amorphous polyester resin A may be composed of resins having different softening points. The difference in softening point between the two resins is preferably 10° C. or more, more preferably 20° C. or more, and is preferably 60° C. or less, more preferably 40° C. or less.

[0058] The softening point of the amorphous resin having a higher softening point (resin AH) is preferably 100°C or higher, more preferably 110°C or higher, and even more preferably 120°C or higher, from the viewpoint of fixing width, and is preferably 170°C or lower, more preferably 160°C or lower, and even more preferably 150°C or lower, from the viewpoint of low-temperature fixability.

[0059] Furthermore, the softening point of the amorphous resin having a lower softening point (resin AL) is preferably 70°C or higher, more preferably 90°C or higher, and even more preferably 100°C or higher from the viewpoint of charging stability, and is preferably 130°C or lower, more preferably 125°C or lower, and even more preferably 120°C or lower from the viewpoint of low-temperature fixability.

[0060] The mass ratio of resin AH to resin AL (resin AH / resin AL) is preferably 10 / 90 or more, more preferably 20 / 80 or more, even more preferably 30 / 70 or more, and is preferably 90 / 10 or less, more preferably 80 / 20 or less, even more preferably 75 / 25 or less.

[0061] The glass transition temperature of the amorphous polyester resin A is preferably 40°C or higher, more preferably 50°C or higher, from the viewpoint of pressurized storage stability, and is preferably 80°C or lower, more preferably 70°C or lower, from the viewpoint of charging stability.

[0062] The acid value of the amorphous polyester resin A is preferably 1 mgKOH / g or more, more preferably 3 mgKOH / g or more, from the viewpoint of charging stability, and is preferably 20 mgKOH / g or less, more preferably 18 mgKOH / g or less, from the viewpoint of pressurized storage stability.

[0063] The content of amorphous polyester resin A in the total amount of crystalline polyester resin C and amorphous polyester resin A is preferably 70% by mass or more, more preferably 75% by mass or more, and even more preferably 80% by mass or more, from the viewpoints of charging stability and pressurized storage stability, and is preferably 97% by mass or less, more preferably 95% by mass or less, and even more preferably 92% by mass or less.

[0064] From the viewpoints of charging stability and pressurized storage stability, the mass ratio of crystalline polyester resin C to amorphous polyester resin A (crystalline polyester resin C / amorphous polyester resin A) is preferably 3 / 97 or more, more preferably 5 / 95 or more, even more preferably 8 / 92 or more, and is preferably 30 / 70 or less, more preferably 25 / 75 or less, even more preferably 20 / 80 or less.

[0065] In the toner, the crystalline polyester resin C and the amorphous polyester resin A are contained as binder resins.

[0066] 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.

[0067] The total content of the crystalline polyester resin C and the amorphous polyester resin A in the binder resin is preferably 70% by mass or more, more preferably 80% by mass or more, even more preferably 90% by mass or more, even more preferably 95% by mass or more, and still more preferably 100% by mass.

[0068] The content of the binder resin in the toner is preferably 60% by mass or more, more preferably 70% by mass or more, and even more preferably 80% by mass or more, and is preferably less than 100% by mass, more preferably 98% by mass or less, and even more preferably 95% by mass or less.

[0069] The toner for developing electrostatic images 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.

[0070] As the colorant, dyes, pigments, magnetic materials, etc. used as toner colorants can be used. Examples include 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, disazo yellow, etc. In the present invention, the toner may be either a black toner or a color toner.

[0071] 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 is 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.

[0072] Examples of the release agent include hydrocarbon waxes such as polypropylene wax, polyethylene wax, ethylene-propylene copolymer wax, microcrystalline wax, paraffin wax, and Fischer-Tropsch wax, 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.

[0073] The melting point of the release agent is preferably 60°C or higher, more preferably 70°C or higher, from the viewpoint of pressurized storage stability of the toner, 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.

[0074] 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 charge stability and pressurized storage stability 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.

[0075] 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.

[0076] Examples of 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" (manufactured by Orient Chemical Industries Co., Ltd.). VP435 (manufactured by Clariant), etc.; polyamine resins, for example, "AFP-B" (manufactured by Orient Chemical Industries, Ltd.), etc.; imidazole derivatives, for example, "PLZ-2001" and "PLZ-8001" (both manufactured by Shikoku Chemical Industries, Ltd.), etc.; styrene-acrylic resins, for example, "FCA-701PT" and "FCA-201-PS" (manufactured by Fujikura Chemical Industries, Ltd.), etc.

[0077] Examples of negatively chargeable charge control agents include metal-containing azo dyes, such as "Barifast Black 3804," "Bontron S-31," "Bontron S-32," "Bontron S-34," and "Bontron S-36" (all manufactured by Orient Chemical Industries, Ltd.), "Eizenspiron 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.

[0078] 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 is 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.

[0079] The toner may be a toner obtained by any conventionally known method such as a melt-kneading method, an emulsion aggregation method, or a suspension polymerization method, and may also be a toner having a core-shell structure, but from the viewpoint of charge stability, 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 containing a crystalline polyester resin C and an amorphous polyester resin A, and, if necessary, a colorant, a release agent, and a charge control agent are uniformly mixed in a mixer such as a Henschel mixer, and then the mixture is 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.

[0080] 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 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.

[0081] Examples of hydrophobic treatment agents for hydrophobizing the surfaces of silica particles include hexamethyldisilazane (HMDS), dimethyldichlorosilane (DMDS), cyclic silazanes, silicone oils, aminosilanes, octyltriethoxysilane (OTES), and methyltriethoxysilane.

[0082] From the viewpoint of the chargeability, fluidity, and transferability of the toner, the average particle size of the external additive is preferably 5 nm or more, more preferably 10 nm or more, and even 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.

[0083] The external addition treatment by mixing the toner particles with the external additives can be carried out in accordance with a conventional method, and a mixer such as a Henschel mixer can be used.

[0084] 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.

[0085] 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 a particle size at which the cumulative volume frequency calculated by volume fraction is 50% counted 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.

[0086] 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.

[0087] In relation to the above-described embodiment, the present invention further discloses the following toner for developing electrostatic images.

[0088] <1> A toner for developing electrostatic images, comprising a crystalline polyester resin C and an amorphous polyester resin A, wherein the crystalline polyester resin C is a polycondensate of an alcohol component containing 70 mol % or more of ethylene glycol and a carboxylic acid component containing an aliphatic dicarboxylic acid compound, the alcohol component and / or the carboxylic acid component containing a monofunctional monomer, and the amorphous polyester resin A is a polycondensate of the alcohol component, the carboxylic acid component, and polyethylene terephthalate.

[0089] <2> The electrostatic image developing toner according to <1> above, wherein the crystalline polyester resin C is a polycondensate of an alcohol component containing ethylene glycol and a carboxylic acid component containing an aliphatic dicarboxylic acid compound. <3> The electrostatic image developing toner according to <2> above, wherein the content of ethylene glycol in the alcohol component is preferably 80 mol% or more, more preferably 90 mol% or more, even more preferably 95 mol% or more and 100 mol% or less, and when the alcohol component contains a monoalcohol, the content is preferably 98 mol% or less, more preferably 95 mol% or less. <4> The electrostatic image developing toner according to any one of <1> to <3> above, wherein in the crystalline polyester resin C, the aliphatic dicarboxylic acid compound has 4 or more carbon atoms, preferably 8 or more, more preferably 10 or more, even more preferably 12 or more, and 16 or less, preferably 14 or less. <5> The electrostatic image developing toner according to any one of <1> to <4>, wherein in the crystalline polyester resin C, the content of the aliphatic dicarboxylic acid compound in the carboxylic acid component is 80 mol% or more, preferably 90 mol% or more, more preferably 95 mol% or more, and 100 mol% or less, and when the carboxylic acid component contains a monocarboxylic acid compound, the content is preferably 98 mol% or less, more preferably 95 mol% or less. <6> The electrostatic image developing toner according to any one of <1> to <5>, wherein in the crystalline polyester resin C, the monofunctional monomer contains an aliphatic monocarboxylic acid compound and / or an aliphatic monoalcohol. <7> The electrostatic image developing toner according to any one of <6>, wherein the aliphatic monoalcohol has 6 or more carbon atoms, preferably 9 or more, more preferably 10 or more, and even more preferably 12 or more, and 24 or less, preferably 23 or less, and more preferably 22 or less. <8> The toner for developing electrostatic images according to the above <6> or <7>, wherein the aliphatic monocarboxylic acid compound has 6 or more, preferably 9 or more, more preferably 10 or more, carbon atoms, and 24 or less, preferably 23 or less, more preferably 22 or less.<9> The electrostatic image developing toner according to any one of <1> to <5> above, wherein in the crystalline polyester resin C, the monofunctional monomer contains an aliphatic monocarboxylic acid compound having from 9 to 24 carbon atoms and / or an aliphatic monoalcohol having from 9 to 24 carbon atoms. <10> The electrostatic image developing toner according to any one of <1> to <9> above, wherein in the crystalline polyester resin C, the content of the monofunctional monomer is 2 mol % or more, preferably 3 mol % or more, more preferably 5 mol % or more, and 30 mol % or less, preferably 25 mol % or less, more preferably 20 mol % or less, based on the total amount of the alcohol component and the carboxylic acid component. <11> The electrostatic image developing toner according to any one of <1> to <10> above, wherein the softening point of the crystalline polyester resin C is 50°C or more, preferably 65°C or more, more preferably 70°C or more, and 120°C or less, preferably 110°C or less. <12> The electrostatic image developing toner according to any one of <1> to <11> above, wherein the crystalline polyester resin C has a melting point of 60° C. or higher, preferably 70° C. or higher, and 130° C. or lower, preferably 120° C. or lower. <13> The electrostatic image developing toner according to any one of <1> to <12> above, wherein the content of the crystalline polyester resin C is 3% by mass or higher, preferably 5% by mass or higher, more preferably 8% by mass or higher, and 30% by mass or lower, preferably 25% by mass or lower, more preferably 20% by mass or lower, based on the total amount of the crystalline polyester resin C and the amorphous polyester resin A. <14> The electrostatic image developing toner according to any one of <1> to <13> above, wherein the alcohol component in the amorphous polyester resin A contains an aliphatic diol having from 3 to 6 carbon atoms. <15> The toner for developing electrostatic images according to <14>, wherein the aliphatic diol having 3 to 6 carbon atoms contains at least one selected from the group consisting of 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 2,3-butanediol, 1,5-pentanediol, neopentyl glycol, and 1,6-hexanediol, and preferably contains neopentyl glycol.<16> The toner for developing electrostatic images according to <14> or <15>, wherein the content of the aliphatic diol having from 3 to 6 carbon atoms in the alcohol component is 30 mol % or more, preferably 40 mol % or more, more preferably 50 mol % or more and 100 mol % or less, and when the alcohol component contains a trihydric or higher alcohol, the content is preferably 98 mol % or less, more preferably 90 mol % or less. <17> The toner for developing electrostatic images according to any one of <1> to <16>, wherein the polyethylene terephthalate is a low IV polyethylene terephthalate, and the IV value of the polyethylene terephthalate is 0.40 or more, preferably 0.45 or more, more preferably 0.50 or more, even more preferably 0.55 or more, and 0.85 or less, preferably 0.80 or less, more preferably 0.75 or less, even more preferably 0.70 or less, and even more preferably 0.65 or less. <18> The toner for developing electrostatic images according to the above <17>, wherein the content of the low IV polyethylene terephthalate is 90% by mass or more, preferably 95% by mass or more, more preferably 98% by mass or more, and even more preferably 100% by mass, based on the total amount of polyethylene terephthalate to be subjected to polycondensation. <19> The toner for developing electrostatic images according to any one of the above <1> to <18>, wherein the content of polyethylene terephthalate in the amorphous polyester resin A is 5 mol % or more, preferably 10 mol % or more, more preferably 15 mol % or more, and even more preferably 20 mol % or more, and 75 mol % or less, preferably 70 mol % or less, and more preferably 65 mol % or less, based on the total amount of the alcohol component, the carboxylic acid component, and the polyethylene terephthalate, based on 1 mol of a terephthalic acid-ethylene glycol unit. <20> The toner for developing electrostatic images according to any one of <1> to <19>, wherein the softening point of the amorphous polyester resin A is 70°C or higher, preferably 90°C or higher, more preferably 100°C or higher, and 170°C or lower, preferably 160°C or lower, more preferably 150°C or lower.<21> The electrostatic image developing toner according to any one of <1> to <20> above, wherein the amorphous polyester resin A contains amorphous resins having different softening points, and the difference in softening points is 10° C. or more, preferably 20° C. or more, and 60° C. or less, and preferably 40° C. or less. <22> The electrostatic image developing toner according to <21> above, wherein the softening point of the amorphous resin having the higher softening point is 100° C. or more, preferably 110° C. or more, more preferably 120° C. or more, and 170° C. or less, preferably 160° C. or less, and more preferably 150° C. or less. <23> The electrostatic image developing toner according to <21> or <22> above, wherein the softening point of the amorphous resin having the lower softening point is 70° C. or more, preferably 90° C. or more, more preferably 100° C. or more, and 130° C. or less, and preferably 125° C. or less, and more preferably 120° C. or less. <24> The electrostatic image developing toner according to any one of the above <21> to <23>, wherein the mass ratio of the amorphous resin having a higher softening point (resin AH) to the amorphous resin having a lower softening point (resin AL) (resin AH / resin AL) is 10 / 90 or more, preferably 20 / 80 or more, more preferably 30 / 70 or more, and 90 / 10 or less, preferably 80 / 20 or less, more preferably 75 / 25 or less. <25> The electrostatic image developing toner according to any one of the above <1> to <24>, wherein the amorphous polyester resin A has a glass transition temperature of 40°C or more, preferably 50°C or more, and 80°C or less, preferably 70°C or less. <26> The electrostatic image developing toner according to any one of <1> to <25>, wherein the content of the amorphous polyester resin A is 70% by mass or more, preferably 75% by mass or more, more preferably 80% by mass or more, and 97% by mass or less, preferably 95% by mass or less, more preferably 92% by mass or less, of the total amount of the crystalline polyester resin C and the amorphous polyester resin A.<27> The electrostatic image developing toner according to any one of the above <1> to <26>, wherein the mass ratio of the crystalline polyester resin C to the amorphous polyester resin A (crystalline polyester resin C / amorphous polyester resin A) is 3 / 97 or more, preferably 5 / 95 or more, more preferably 8 / 92 or more, and 30 / 70 or less, preferably 25 / 75 or less, more preferably 20 / 80 or less. <28> The electrostatic image developing toner according to any one of the above <1> to <27>, wherein the crystalline polyester resin C and the amorphous polyester resin A are contained as binder resins, and the total content of the crystalline polyester resin C and the amorphous polyester resin A in the binder resin is 70% by mass or more, 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. <29> The toner for developing electrostatic images according to <28> above, wherein the content of the binder resin in the toner is 60% by mass or more, preferably 70% by mass or more, more preferably 80% by mass or more, and less than 100% by mass, preferably 98% by mass or less, more preferably 95% by mass or less. <30> The toner for developing electrostatic images according to any one of <1> to <29> above, wherein the toner is a pulverized toner.

[0090] 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.

[0091] [IV Value of PET] A PET is dissolved in a 60 / 40 (mass ratio) mixed solvent of phenol / tetrachloroethane at a concentration of 4 g / L, and the IV value is measured using an Ubbelohde viscometer. The IV value is calculated using the following formula: IV = (-1 + √(1 + 4kη)) / (2kC) (where k = 0.33, C = 0.004 g / mL, and η = (t １ / t ０ ) −1(t ０ : Time in seconds for the solvent to fall, t １ : the number of seconds it takes for the sample solution to fall.)

[0092] [Softening Point of Resin] Using a flow tester "CFT-500D" (manufactured by Shimadzu Corporation), 1 g of a sample is heated at a temperature increase rate of 6°C / min, while a load of 1.96 MPa is applied by the plunger, and the sample is extruded from a nozzle with a diameter of 1 mm and a length of 1 mm. 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.

[0093] [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 temperature decrease rate of 10°C / min, and maintained at 0°C for 1 minute. Thereafter, measurements are made at a temperature increase rate of 10°C / min. Of the endothermic peaks observed, the temperature of the peak with the largest peak area is taken as the maximum endothermic peak temperature. For crystalline resins, the maximum endothermic peak temperature is taken as the melting point.

[0094] [Glass Transition Temperature of Resin] Using a differential scanning calorimeter "Q-100" (manufactured by TA Instruments Japan Co., Ltd.), 0.01 to 0.02 g of a sample is weighed into an aluminum pan, heated to 200°C, and cooled from that temperature 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.

[0095] [Acid value of resin] Measured based on the method of JIS K 0070: 1992. However, only the measurement solvent is changed from the mixed solvent of ethanol and ether specified in JIS K 0070 to a mixed solvent of acetone and toluene (acetone:toluene=1:1 (volume ratio)) for amorphous resins, and to a mixed solvent of chloroform and dimethylformamide (chloroform:dimethylformamide=7:3 (volume ratio)) for crystalline resins.

[0096] [Melting Point of Mold Release Agent] Using a differential scanning calorimeter "Q-100" (manufactured by TA Instruments Japan Co., Ltd.), 0.02 g of a sample is weighed into an aluminum pan, heated to 200°C, and then cooled from 200°C to 0°C at a temperature decrease rate of 10°C / min. Next, the sample is heated at a temperature increase rate of 10°C / min, the amount of heat is measured, and the maximum endothermic peak temperature is taken as the melting point.

[0097] [Volume median particle diameter and CV value of resin particles, colorant particles, and release agent particles] (1) Measuring device: Laser diffraction particle size measuring instrument "LA-920" (manufactured by Horiba, Ltd.) (2) Measuring conditions: A sample dispersion was placed in a measuring cell, distilled water was added, and the volume median particle diameter (D ５０ The CV value is calculated according to the following formula: CV value (%) = (standard deviation of particle size distribution / volume average particle size) x 100

[0098] [Solid content concentration of resin dispersion, colorant dispersion, and release agent dispersion] Using an infrared moisture meter "FD-230" (manufactured by Kett Electric Laboratory Co., Ltd.), 5 g of a measurement sample is dried at a drying temperature of 150°C and measurement mode 96 (monitoring time 2.5 minutes, fluctuation range 0.05%), and the moisture content (mass %) of the dispersion is measured. The solid content concentration is calculated according to the following formula: Solid content concentration (mass %) = 100 - moisture (mass %)

[0099] [Volume Median Particle Size of Aggregated Particles] Measuring instrument: "Coulter Multisizer (registered trademark) III" (Beckman Coulter, Inc.) Aperture diameter: 50 μm Analysis software: "Multisizer (registered trademark) III Version 3.51" (Beckman Coulter, Inc.) Electrolyte: "Isoton (registered trademark) II" (Beckman Coulter, Inc.) Measurement conditions: A sample dispersion was added to 100 mL of the electrolyte to adjust the concentration so that the particle sizes of 30,000 particles could be measured in 20 seconds, and then 30,000 particles were measured, and the volume median particle size (D ５０ ) is required.

[0100] [Average Particle Diameter of External Additive] The average particle diameter refers to the number-average particle diameter, and is determined by measuring the particle diameters (average values ​​of major and minor axes) of 500 particles in a scanning electron microscope (SEM) photograph and averaging these values ​​by number.

[0101] [Volume median particle size of toner (D ５０ ) Measuring instrument: "Coulter Multisizer (registered trademark) III" (Beckman Coulter, Inc.) Aperture diameter: 50 μm Analysis software: "Multisizer (registered trademark) III Version 3.51" (Beckman Coulter, Inc.) Electrolyte: "Isoton (registered trademark) II" (Beckman Coulter, Inc.) Dispersion: Polyoxyethylene lauryl ether "Emulgen (registered trademark) 109P" (Kao Corporation, HLB (Griffin) = 13.6) was dissolved in electrolyte to adjust the concentration to 5% by mass Dispersion conditions: 10 mg of a 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), and then 25 mL of electrolyte was 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 diameter of 30,000 particles could be measured in 20 seconds. Then, 30,000 particles were measured, and the volume median particle diameter (D ５０ ) is required.

[0102] [Toner Circularity] The circularity of toner particles is measured under the following conditions: Measuring device: Flow type particle image analyzer "FPIA-3000" (manufactured by Sysmex Corporation) Preparation of dispersion: The dispersion of toner particles is diluted with deionized water to prepare a solid content concentration of 0.001 to 0.05% by mass. Measurement mode: HPF measurement mode

[0103] Resin Production Example 1: The alcohol component, carboxylic acid component, PET, esterification catalyst, and cocatalyst shown in Tables 1 to 6 were placed in a 10-liter four-neck flask equipped with a nitrogen inlet tube, a stirrer, and a thermocouple. Under a nitrogen atmosphere, the mixture was maintained at 180°C for 1 hour, then heated from 180°C to 235°C at a rate of 10°C / h, and polycondensed at 235°C for 5 hours. The mixture was then cooled to 210°C and reacted under a reduced pressure of 10 kPa until the softening point shown in Tables 1 to 6 was reached, yielding amorphous polyester resins (resins AH1 to AH7, AH12, AH13, and resins AL1 to AL6, AL11, and AL12). The physical properties are shown in Tables 1 to 6.

[0104] Resin Production Example 2: The alcohol component, carboxylic acid component other than trimellitic anhydride, PET, esterification catalyst, and cocatalyst shown in Tables 2 and 3 were placed in a 10-liter four-neck flask equipped with a nitrogen inlet tube, stirrer, and thermocouple. The mixture was heated to 235°C under a nitrogen atmosphere and then polycondensed at 235°C for 6 hours. The temperature was then lowered to 210°C, and trimellitic anhydride shown in Tables 2 and 3 was added. The mixture was reacted at 210°C for 1 hour, and then further reacted at 210°C under a reduced pressure of 10 kPa until the softening point shown in Tables 2 and 3 was reached, yielding amorphous polyester resins (Resins AH8, AH11, and AH14). The physical properties are shown in Tables 2 and 3.

[0105] Resin Production Example 3: The alcohol component, carboxylic acid component, esterification catalyst, and cocatalyst shown in Tables 2 and 5 were placed in a 5-liter four-neck flask equipped with a nitrogen inlet tube, a dehydration tube fitted with a fractionating column through which hot water at 98°C had passed, a stirrer, and a thermocouple. The mixture was maintained at 180°C for 1 hour under a nitrogen atmosphere, then heated from 180°C to 235°C at a rate of 10°C / h, and polycondensed at 235°C for 5 hours. The temperature was then lowered to 210°C, and the reaction was continued at 210°C under a reduced pressure of 10 kPa until the softening point shown in Tables 2 and 5 was reached, yielding amorphous polyester resins (Resins AH9 to AH10, AL8 to AL9). The physical properties are shown in Tables 2 and 5.

[0106] Resin Production Example 4: The alcohol component, carboxylic acid component, PET, esterification catalyst, and cocatalyst shown in Tables 5 and 6 were placed in a 10-liter four-neck flask equipped with a nitrogen inlet tube, stirrer, and thermocouple, and the temperature was raised to 235°C under a nitrogen atmosphere, followed by polycondensation at 235°C for 6 hours. The temperature was then lowered to 210°C, and the reaction was continued under a reduced pressure of 10 kPa until the softening points shown in Tables 5 and 6 were reached, yielding amorphous polyester resins (resins AL7, AL10, and AL13). The physical properties are shown in Tables 5 and 6.

[0107]

[0108]

[0109]

[0110]

[0111]

[0112]

[0113] Resin Production Example 5: The alcohol components and carboxylic acid components shown in Tables 7 and 8 were placed in a 10-liter four-neck flask equipped with a thermometer, a stainless steel stirring rod, a downflow condenser, and a nitrogen inlet tube, and the temperature was raised to 200°C over 8 hours in a nitrogen atmosphere in a mantle heater. Subsequently, an esterification catalyst shown in Tables 7 and 8 was added, and the reaction was carried out at 8.0 kPa until the softening points shown in Tables 7 and 8 were reached, yielding crystalline polyester resins (resins C1 to C11). Their physical properties are shown in Tables 7 and 8.

[0114]

[0115]

[0116] Examples 1 to 17, 20 to 25, Comparative Examples 1 to 4 (Melt-Kneading Method) 100 parts by mass of a binder resin shown in Table 9, 5 parts by mass of a colorant "ECB-301" (manufactured by Dainichiseika Color & Chemicals Mfg. Co., Ltd., phthalocyanine blue (P.B.15:3)), 3 parts by mass of a release agent "Carnauba Wax C1" (manufactured by Kato Yoko Co., Ltd., melting point: 83°C), and 0.5 parts by mass of a negatively chargeable charge control agent "Bontron E-304" (manufactured by Orient Chemical Industries Co., Ltd.) were mixed in a Henschel mixer.

[0117] The resulting mixture was melt-kneaded using a co-rotating twin-screw extruder having a kneading section with a total length of 1560 mm, a screw diameter of 42 mm, and a barrel inner diameter of 43 mm at a screw rotation speed of 200 r / min and a barrel temperature setting of 100° C. to obtain a melt-kneaded product. The feed rate of the mixture was 20 kg / h, and the average residence time was about 18 seconds.

[0118] The resulting melt-kneaded product was cooled and coarsely crushed, then crushed in a jet mill, and classified using an air classifier (manufactured by Nippon Pneumatic Mfg. Co., Ltd.) to obtain a volume median particle size (D ５０ ) toner particles of 7.0 μm were obtained.

[0119] 100 parts by mass of the obtained toner particles and, as external additives, 1.0 part by mass of hydrophobic silica "R972" (manufactured by Nippon Aerosil Co., Ltd., hydrophobic treatment agent: DMDS, average particle size: 16 nm) and 1.0 part by mass of hydrophobic silica "RY-50" (manufactured by Nippon Aerosil Co., Ltd., hydrophobic treatment agent: silicone oil, average particle size: 40 nm) were mixed in a Henschel mixer (manufactured by Nippon Coke and Engineering Co., Ltd.) at a rotation speed of 3000 r / min (circumferential speed: 32 m / sec) for 3 minutes to obtain a toner.

[0120] Example 18 A toner was obtained in the same manner as in Example 1, except that a continuous open-roll twin-screw kneader "Kneedex" (manufactured by Nippon Coke and Engineering Co., Ltd.) was used for melt-kneading instead of the co-rotating twin-screw extruder. The continuous open-roll twin-screw kneader had a roll outer diameter of 0.14 m and an effective roll length of 0.8 m. The operating conditions were a rotation speed of the high-speed roll (front roll) of 75 r / min (circumferential speed of 33 m / min), a rotation speed of the low-speed roll (rear roll) of 50 r / min (circumferential speed of 22 m / min), and a roll gap of 0.1 mm. The heating and cooling medium temperatures within the rolls were set as follows: the temperature on the raw material inlet side of the high-speed roll was 140°C, and the temperature on the kneaded material outlet side was 110°C; and the temperature on the raw material inlet side of the low-speed roll was 65°C, and the temperature on the kneaded material outlet side was 30°C. The raw material mixture was supplied at a rate of 10 kg / h, and the average residence time was approximately 5 minutes.

[0121] Example 19 [Emulsion Aggregation Method] <Preparation of Core Resin Dispersion> 600 g of methyl ethyl ketone was placed in a 5-liter vessel equipped with a stirrer, reflux condenser, dropping funnel, thermometer, and nitrogen inlet tube, and 129 g of Resin AH1 and 21 g of Resin C1 were added at 60°C and dissolved. A 5% by mass aqueous solution of sodium hydroxide was added to the resulting solution so that the degree of neutralization relative to the acid value of the resin was 60 mol%, and the mixture was stirred for 30 minutes to obtain a mixture. Subsequently, 675 g of deionized water was added over 77 minutes. Next, while stirring at 250 r / min, the methyl ethyl ketone was distilled off under reduced pressure at a temperature of 50°C or less, and the solids concentration of the aqueous dispersion was measured. The solids concentration of the aqueous dispersion was adjusted to 20% by mass with deionized water to obtain a core resin dispersion. The volume median particle diameter (D ５０ ) was 200 nm and the CV value was 24%.

[0122] <Preparation of Shell Resin Dispersion> 600 g of methyl ethyl ketone was placed in a 5-liter container equipped with a stirrer, reflux condenser, dropping funnel, thermometer, and nitrogen inlet tube, and 150 g of resin AL1 was added at 60 ° C. and dissolved. A 5% by mass aqueous solution of sodium hydroxide was added to the resulting solution so that the degree of neutralization was 60 mol% relative to the acid value of the resin, and the mixture was stirred for 30 minutes to obtain a mixture. Subsequently, 675 g of deionized water was added over 77 minutes. Next, while stirring at 250 r / min, methyl ethyl ketone and a portion of the water were distilled off under reduced pressure at a temperature of 50 ° C. or less, and the solids concentration of the aqueous dispersion was measured, and the solids concentration of the aqueous dispersion was adjusted to 20% by mass with deionized water to obtain a shell resin dispersion. The volume median particle size (D ５０ ) was 110 nm and the CV value was 20%.

[0123] <Preparation of Colorant Dispersion> Into a 1-liter beaker, 116.2 g of colorant "ECB-301" (manufactured by Dainichiseika Color & Chemicals Mfg. Co., Ltd., phthalocyanine blue (P.B.15:3)), 154.9 g of anionic surfactant "Neopelex (registered trademark) G-15" (manufactured by Kao Corporation, 15% by mass aqueous solution of sodium dodecylbenzenesulfonate), and 260 g of deionized water were mixed and dispersed using a homogenizer at room temperature for 3 hours, and then deionized water was added so that the solids concentration became 24% by mass, thereby obtaining a colorant dispersion. The volume median particle diameter (D ５０ ) was 118 nm and the CV value was 27%.

[0124] <Preparation of Release Agent Dispersion> 50 g of Fischer-Tropsch wax (manufactured by Nippon Seiro Co., Ltd., trade name: FNP0090, melting point: 90°C), 5 g of a cationic surfactant (manufactured by Kao Corporation, trade name: Sanisol B50) and 200 g of deionized water were heated to 95°C, and the wax was dispersed using a homogenizer. The mixture was then subjected to a dispersion treatment using a pressure discharge homogenizer, thereby obtaining a release agent dispersion having a solids concentration of 20% by mass. The volume median particle diameter (D ５０ ) was 550 nm and the CV value was 26%.

[0125] <Preparation of Toner Particles> 500 g of the core resin dispersion, 36 g of the colorant dispersion, 33 g of the release agent dispersion, and 3.3 g of a 15% by mass aqueous solution of sodium dodecylbenzenesulfonate "Neopelex G-15" (manufactured by Kao Corporation, an anionic surfactant) were mixed at a temperature of 25°C in a 3-liter four-neck flask equipped with a dehydration tube, a stirrer, and a thermocouple. Next, while stirring the resulting mixture, a solution prepared by dissolving 40 g of ammonium sulfate in 570 g of deionized water and adding a 4.8% by mass aqueous solution of potassium hydroxide to adjust the pH to 8.2 was added dropwise over 10 minutes at 25°C, and the temperature was then raised to 62°C over 2 hours to measure the volume median particle diameter (D ５０ The temperature was maintained at 62° C. until the particle size reached 6.9 μm, thereby obtaining a dispersion of aggregated particles (I).

[0126] While maintaining the temperature of the obtained dispersion of aggregated particles (I) at 62° C., 215 g of the shell resin dispersion was added dropwise at a rate of 0.6 mL / min (0.6 g / min) to obtain a dispersion of aggregated particles (II). ５０ ) was 7.0 μm.

[0127] To the resulting dispersion of aggregated particles (II), an aqueous solution prepared by mixing 20 g of polyoxyethylene lauryl ether sodium sulfate "EMAL E-27C" (manufactured by Kao Corporation, anionic surfactant, effective concentration 27% by mass), 280 g of deionized water, and 40 g of a 0.1 mol / L aqueous sulfuric acid solution was added. The mixture was then heated to 80°C over 1 hour and maintained at 80°C for 30 minutes. Thereafter, 10 g of a 0.1 mol / L aqueous sulfuric acid solution was added, and the mixture was further maintained at 80°C for 15 minutes. Thereafter, 15 g of a 0.1 mol / L aqueous sulfuric acid solution was added again, and the mixture was maintained at 80°C until the circularity reached 0.970, thereby obtaining a dispersion of fused particles (core-shell particles) in which the aggregated particles were fused together.

[0128] The obtained core-shell particle dispersion was cooled to 30°C, and the dispersion was suction filtered to separate the solids. The solids were then washed with deionized water at 25°C and suction filtered at 25°C for 2 hours. The solids were then vacuum dried at 33°C for 24 hours using a vacuum constant temperature dryer "DRV622DA" (manufactured by ADVANTEC) to obtain toner particles. The particle size of the obtained toner particles was 7.0 μm and the circularity was 0.970. The composition ratio (mass ratio) of the binder resins in the obtained toner particles was Resin AH1 / Resin AL1 / Resin C1 = 60 / 30 / 10.

[0129] 100 parts by mass of the obtained toner particles and, as external additives, 1.0 part by mass of hydrophobic silica "R972" (manufactured by Nippon Aerosil Co., Ltd., hydrophobic treatment agent: DMDS, average particle size: 16 nm) and 1.0 part by mass of hydrophobic silica "RY-50" (manufactured by Nippon Aerosil Co., Ltd., hydrophobic treatment agent: silicone oil, average particle size: 40 nm) were mixed in a Henschel mixer (manufactured by Nippon Coke and Engineering Co., Ltd.) at a rotation speed of 3000 r / min (circumferential speed: 32 m / sec) for 3 minutes to obtain a toner.

[0130] Test Example 1 [Charge Stability of Toner] Under conditions of a temperature of 25°C and a relative humidity of 50%, 0.6 g of toner and 19.4 g of silicone ferrite carrier (manufactured by Kanto Denka Kogyo Co., Ltd., average particle size 90 μm) were placed in a 50 mL polyethylene container and mixed using a ball mill at 250 r / min, and the charge amount of the toner was measured using a Q / M meter (manufactured by EPPING Co., Ltd.) using the following method.

[0131] After 60 or 600 seconds of mixing, a specified amount of toner and carrier mixture was placed in a cell attached to a Q / M meter, and the toner alone was sucked through a 32 μm mesh sieve (stainless steel, twill weave, wire diameter: 0.0035 mm) for 90 seconds. The voltage change on the carrier was monitored, and the value [total charge (μC) after 90 seconds / sucked toner amount (g)] was taken as the charge amount (μC / g). The ratio of the charge amount after 60 seconds of mixing to the charge amount after 600 seconds of mixing (charge amount after 60 seconds of mixing / charge amount after 600 seconds of mixing) was calculated to evaluate charge stability. The results are shown in Table 9. A higher value indicates better charge stability.

[0132] Test Example 2 (Pressurized Storage Stability of Toner) 10 g of toner was placed in a cylindrical container with a radius of 12 mm, a 100 g weight was placed on top, and the container was stored under pressure at 50°C and a relative humidity of 60% for 24 hours. Three sieves, namely, sieve A (mesh size: 250 μm), sieve B (mesh size: 150 μm), and sieve C (mesh size: 75 μm), were placed one on top of the other in a powder tester (manufactured by Hosokawa Micron Corporation). 10 g of the toner stored under pressure was placed on sieve A and vibrated for 60 seconds. The weights of the toner remaining on sieve A (WA, g), sieve B (WB, g), and sieve C (WC, g) were measured, and the weights of the toner remaining on sieve A (WA, g), sieve B (WB, g), and sieve C (WC, g) were evaluated for pressurized storage stability based on the value (α) calculated according to the following formula and the following evaluation criteria. The results are shown in Table 9. The closer the value (α) is to 100, the better the storage stability under pressure. α=100-(WA+WB×0.6+WC×0.2) / 10×100

[0133]

[0134] From the above results, it can be seen that Examples 1 to 25 have both good charge stability and pressure storage stability. In contrast, the toners of Comparative Examples 1 and 2, which contain amorphous polyester resins without PET, are insufficient in both charge stability and pressure storage stability. In particular, Comparative Example 2 shows that using ethylene glycol and terephthalic acid, which are monomer components of PET, is ineffective, and that using PET is important. Furthermore, with regard to the crystalline polyester resin, Comparative Example 3, which does not use ethylene glycol, shows a significant decrease in pressure storage stability, and Comparative Example 4, which does not use a monofunctional monomer, shows a significant decrease in charge stability.

[0135] 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. A toner for developing electrostatic images comprising crystalline polyester resin C and amorphous polyester resin A, wherein the crystalline polyester resin C is a polycondensation product of an alcohol component containing 70 mol% or more of ethylene glycol and a carboxylic acid component containing an aliphatic dicarboxylic acid compound, the alcohol component and / or the carboxylic acid component containing a monofunctional monomer, and the amorphous polyester resin A is a polycondensation product of an alcohol component, a carboxylic acid component and polyethylene terephthalate.

2. The toner for developing electrostatic images according to claim 1, wherein the content of polyethylene terephthalate in the amorphous polyester resin A is 5 mol % or more and 75 mol % or less of the total amount of the alcohol component, the carboxylic acid component and the polyethylene terephthalate, assuming that a terephthalic acid-ethylene glycol unit is 1 mol.

3. The toner for developing electrostatic images according to claim 1, wherein the content of polyethylene terephthalate in the amorphous polyester resin A is 15 mol % or more and 65 mol % or less of the total amount of the alcohol component, the carboxylic acid component and the polyethylene terephthalate, assuming that a terephthalic acid-ethylene glycol unit is 1 mol.

4. The toner for developing electrostatic images according to any one of claims 1 to 3, wherein the IV value of the polyethylene terephthalate is 0.40 or more and 0.80 or less.

5. The toner for developing electrostatic images according to any one of claims 1 to 4, wherein the content of the crystalline polyester resin C is from 3% by mass to 30% by mass in the total amount of the crystalline polyester resin C and the amorphous polyester resin A.

6. The toner for developing electrostatic images according to any one of claims 1 to 5, wherein in the crystalline polyester resin C, the monofunctional monomer contains an aliphatic monocarboxylic acid compound having 9 to 24 carbon atoms and / or an aliphatic monoalcohol having 9 to 24 carbon atoms.

7. The toner for developing electrostatic images according to any one of claims 1 to 6, wherein in the crystalline polyester resin C, the content of the monofunctional monomer is from 2 mol % to 30 mol % in the total amount of the alcohol component and the carboxylic acid component.

8. The toner for developing electrostatic images according to any one of claims 1 to 7, wherein in the amorphous polyester resin A, the alcohol component contains an aliphatic diol having 3 to 6 carbon atoms.

9. The toner for developing electrostatic images according to claim 8, wherein the content of the aliphatic diol having 3 to 6 carbon atoms is 30 mol % to 100 mol % in the alcohol component.

10. The toner for developing electrostatic images according to any one of claims 1 to 9, wherein in the crystalline polyester resin C, the aliphatic dicarboxylic acid compound has 10 or more and 16 or less carbon atoms.

11. The toner for developing electrostatic images according to any one of claims 1 to 10, wherein the amorphous polyester resin A contains an amorphous resin having a softening point different by 10°C or more.

Images