Toner binder resin composition

Abstract

The present invention relates to a binder resin composition for toner that exhibits excellent durability and gloss under high humidity conditions, and toner for electrostatic image development containing the binder resin composition. [Solution] A binder resin composition for toner containing amorphous polyester resin A and crystalline polyester resin C, wherein the amorphous polyester resin A is a polycondensate of an alcohol component and a carboxylic acid component containing polymerized rosin, and the polymerized rosin content is 2% by mass or more and 40% by mass or less of the carboxylic acid component, and a toner for electrostatic image development containing the binder resin composition.

Description

Technical Field

[0001] The present invention relates to a binder resin composition for toner used for developing a latent image formed in an electrophotographic method, an electrostatic recording method, an electrostatic printing method, etc., and an electrostatic charge image developing toner containing the binder resin composition.

Background Art

[0002] Patent Document 1 discloses an electrophotographic toner polyester resin composition characterized by containing, as a main component, a condensate (A) having a softening point of 90 to 150°C and a glass transition point of 45 to 75°C, which is obtained by reacting a polybasic carboxylic acid containing 25 to 60 mol% of a polymerized rosin and / or a lower ester of the polymerized rosin having a dimer content of 60% by weight or more with a total alcohol component containing 30 to 80 mol% of etherified diphenols.

[0003] Patent Document 2 discloses a binder resin for toner, which contains a polyester resin (A) satisfying the following requirements (i) to (iii) and has a tin content of 1 ppm or less. Requirement (i): It contains a structural unit (A1) derived from an alcohol and a structural unit (A2) derived from a carboxylic acid. Requirement (ii): The structural unit of the bisphenol A skeleton is contained in the structural unit (A1) derived from an alcohol at 1 mol% or less. Requirement (iii): It contains a structural unit derived from rosins as the structural unit (A2) derived from a carboxylic acid.

[0004] Patent Document 3 discloses a toner containing a polyester resin L obtained by polycondensing an alcohol component containing 70 mol% or more of a trivalent or higher aliphatic alcohol and a carboxylic acid component containing a total of 70 mol% or more of rosin and an aliphatic dicarboxylic acid compound having 4 to 10 carbon atoms, the polyester resin L having a softening point of 90 to 135°C and a binder resin having a content of 5 to 40% by weight.

Prior Art Documents

Patent Documents

[0005] [Patent Document 1] Japanese Patent Publication No. 2014-95762 [Patent Document 2] Japanese Patent Publication No. 2005-350597 [Patent Document 3] Japanese Patent Publication No. 2013-114045 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] To improve low-temperature fixation performance, the use of amorphous polyester resin in combination with crystalline polyester resin as a binder resin for toner is being considered. However, while crystalline polyester resin improves low-temperature fixation, its lower dispersibility compared to amorphous polyester resin leads to exposure of the toner surface, forming coarse domains and thus degrading the toner's durability. In particular, under high humidity conditions, the absorption of moisture by the amorphous polyester resin promotes exposure of the crystalline polyester resin to the surface, resulting in an even coarser domain size for the crystalline polyester resin and a significant decrease in durability. Therefore, increasing the molecular weight of the binder resin is useful to improve the durability of the toner. However, increasing the molecular weight results in a higher melt viscosity of the binder resin, which reduces the smoothness of the fixed image surface, making gloss a challenge.

[0007] The present invention relates to a binder resin composition for toner that exhibits excellent durability and gloss under high humidity conditions, and toner for electrostatic image development containing the binder resin composition. [Means for solving the problem]

[0008] The present invention [1] A binder resin composition for toner containing amorphous polyester resin A and crystalline polyester resin C, wherein the amorphous polyester resin A is a polycondensate of an alcohol component and a carboxylic acid component containing polymerized rosin, and the content of the polymerized rosin is 2% by mass or more and 40% by mass or less of the carboxylic acid component, and [2] A toner for developing electrostatic images containing the toner binder resin composition described in [1] above. Regarding. [Effects of the Invention]

[0009] The toner binder resin composition of the present invention exhibits excellent durability and gloss under high humidity conditions. [Modes for carrying out the invention]

[0010] The toner binder resin composition of the present invention contains amorphous polyester resin A and crystalline polyester resin C, and is characterized in that amorphous polyester resin A is a polycondensate obtained using a predetermined amount of polymer rosin. The reason why the electrostatic image developing toner containing the toner binder resin composition of the present invention has excellent durability and gloss under high humidity conditions is not clear, but it is presumed to be as follows. Note that the following mechanism is a hypothesis and is not limited thereto.

[0011] Because polymerized rosin is a low-polarity dicarboxylic acid, it has a high affinity for low-polarity crystalline polyester resins. Therefore, the dispersibility of crystalline polyester resin is high in amorphous polyester resin obtained using polymerized rosin, and the crystalline polyester resin is less likely to be exposed on the toner surface. Furthermore, because polymerized rosin is low-polarity, it has low hygroscopicity, which can suppress moisture absorption by amorphous polyester resin, making it possible to suppress the formation of coarse domains in crystalline polyester resin and improving durability under high humidity conditions. Furthermore, because polymerized rosin has a rigid structure, it is possible to control the molecular weight to a low level relative to the thermophysical properties required for toner. This makes it possible to improve the gloss of the toner without compromising durability. In addition, amorphous polyester resin, which has constituent units derived from polymerized rosin, has high compatibility with crystalline polyester resin. Therefore, it is thought that compatibility during fixing allows the toner to be sufficiently plasticized, improving image smoothness and contributing to improved gloss.

[0012] Amorphous polyester resin A is a polycondensate of an alcohol component and a carboxylic acid component containing polymerized rosin.

[0013] From the viewpoint of gloss, it is preferable that the alcohol component contains an aliphatic diol.

[0014] Aliphatic diols include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 1,2-pentanediol, 1,3-pentanediol, 1,4-pentanediol, 1,5-pentanediol, 2,3-pentanediol, 2,4-pentanediol, 1,2-hexanediol, 1,3-hexanediol, and 1,4-hexanediol. Examples include ol, 1,5-hexanediol, 1,6-hexanediol, 2,3-hexanediol, 3,4-hexanediol, 2,4-hexanediol, 2,5-hexanediol, 1,4-butenediol, neopentyl glycol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,14-tetradecanediol, and the like.

[0015] From the viewpoint of durability, the carbon number of the aliphatic diol is preferably 2 or more, more preferably 3 or more, and from the viewpoint of gloss, it is preferably 6 or less, more preferably 5 or less, and even more preferably 3 or less.

[0016] Among aliphatic diols, aliphatic diols having a hydroxyl group bonded to a secondary carbon atom are preferred.

[0017] The number of carbon atoms of the aliphatic diol having a hydroxyl group bonded to a secondary carbon atom is preferably 3 or more, and preferably 6 or less, more preferably 4 or less.

[0018] Examples of the aliphatic diol having a hydroxyl group bonded to a secondary carbon atom with 3 to 6 carbon atoms include 1,2-propanediol, 1,2-butanediol, 1,3-butanediol, 2,3-butanediol, 1,2-pentanediol, 1,3-pentanediol, 1,4-pentanediol, 2,3-pentanediol, 2,4-pentanediol, and the like.

[0019] The content of the aliphatic diol is preferably 20 mol% or more, more preferably 40 mol% or more, still more preferably 60 mol% or more, and 100 mol% or less in the alcohol component.

[0020] Also, the content of the aliphatic diol having a hydroxyl group bonded to a secondary carbon atom is preferably 20 mol% or more, more preferably 40 mol% or more, still more preferably 60 mol% or more, and 100 mol% or less in the alcohol component.

[0021] Examples of the alcohol component other than the aliphatic diol include Formula (I):

[0022]

Chemical formula

[0023] (In the formula, OR and RO are oxyalkylene groups, R is an ethylene group and / or a propylene group, x and y represent the average number of moles of alkylene oxide added, and are positive numbers respectively. The sum of the values 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, still more preferably 4 or less) Examples include alkylene oxide adducts of bisphenol A represented by , aromatic diols such as bisphenol A, hydrogenated bisphenol A, alicyclic diols such as 1,4-cyclohexanedimethanol, trivalent or higher alcohols such as sorbitol, pentaerythritol, glycerin, and trimethylolpropane.

[0024] The carboxylic acid component contains polymerized rosin. In this specification, polymerized rosin is a reaction mixture obtained by polymerizing rosin of plant origin, and is usually sold as a mixture containing polymers such as rosin dimers and trimers, as well as unreacted rosin. Rosin is a natural resin extracted from pine trees and the like, and mainly contains a mixture of abietic acid and its isomers, which have three ring structures, conjugated double bonds, and carboxyl groups.

[0025] Commercially available polymerized rosin contains polymers of three or more trimers, in which three or more resin acids (rosinic acid) contained in rosin are bonded together; rosin dimers in which two rosinic acid molecules are bonded together and have two functional groups (hereinafter also referred to as "bifunctional rosin dimers"); rosin dimers in which decarboxylation of dicarboxylic acid rosin dimers occurs as a side reaction during the production of polymerized rosin, resulting in the removal of one carboxyl group (hereinafter referred to as "monofunctional rosin dimers"); and rosin dimers in which two carboxyl groups have been removed (hereinafter referred to as "rosin dimers without functional groups"). In addition to these components, rosin dimers in which two rosinic acid molecules are bonded together and have three functional groups (hereinafter referred to as "trifunctional rosin dimers"), unreacted rosinic acid and rosin esters (hereinafter referred to as "rosin monomers"), etc., may also be present.

[0026] On the other hand, in the present invention, polymerized rosin is incorporated into polyester resin, and in particular, bifunctional or more polymers in polymerized rosin participate in the polycondensation reaction, and the functional group is -COOR 1 (R 1 It is presumed that a carboxyl group or its ester group (represented by a hydrogen atom, an alkyl group having 1 to 5 carbon atoms, or a benzyl group) is involved in the polycondensation reaction.

[0027] Polymerized rosin contains polymers in which two or more abietic acid molecules are bonded together, making it useful for compatibility with hydrophobic components such as crystalline polyester resins and mold release agents.

[0028] As the polymer for rosin, commercially available polymerized rosin or polymerized rosin prepared by conventional methods can be used, but from the viewpoint of durability, those with a high proportion of dimers are preferred, and the dimer content in the polymerized rosin is preferably 40% by mass or more, more preferably 45% by mass or more, even more preferably 50% by mass or more, and 100% by mass or less.

[0029] From the above viewpoint, the content of the bifunctional rosin dimer in the polymerized rosin is preferably 25% by mass or more, more preferably 35% by mass or more, even more preferably 40% by mass or more, and preferably 90% by mass or less, more preferably 80% by mass or less, and even more preferably 70% by mass or less.

[0030] The polymerized rosin content is 2% by mass or more, preferably 5% by mass or more, more preferably 10% by mass or more, of the carboxylic acid components (excluding terephthalic acid, which constitutes PET, when PET is used), and from the viewpoint of durability, it is 40% by mass or less, preferably 36% by mass or less, more preferably 32% by mass or less.

[0031] From the viewpoint of durability, it is preferable that the carboxylic acid component further contains an aromatic dicarboxylic acid compound.

[0032] Examples of aromatic dicarboxylic acid compounds include phthalic acid, isophthalic acid, terephthalic acid, anhydrides of these acids, and alkyl esters of these acids with 1 to 3 carbon atoms. Among these, terephthalic acid is preferred.

[0033] The content of aromatic dicarboxylic acid compounds is preferably 60 mol% or more, more preferably 70 mol% or more, even more preferably 80 mol% or more, and preferably 95 mol% or less, and more preferably 90 mol% or less, among the carboxylic acid components other than polymerized rosin.

[0034] The mass ratio of aromatic dicarboxylic acid compounds (excluding terephthalic acid, which constitutes PET, when PET is used) to polymerized rosin (aromatic dicarboxylic acid compound / polymerized rosin) is preferably 1.0 or higher, more preferably 1.5 or higher, even more preferably 2.0 or higher, and preferably 20 or lower, more preferably 15 or lower, and even more preferably 10 or lower.

[0035] Other carboxylic acid components besides polymerized rosin and aromatic dicarboxylic acid compounds include aliphatic dicarboxylic acid compounds and trivalent or higher carboxylic acid compounds.

[0036] Examples of aliphatic dicarboxylic acid compounds include fumaric acid, maleic acid, succinic acid, succinic acid derivatives substituted with hydrocarbon groups, glutaric acid, adipic acid, sebacic acid, anhydrides of these acids, and alkyl esters of these acids with 1 to 3 carbon atoms.

[0037] Examples of carboxylic acid compounds with a valency of 3 or higher include trimellitic acid, pyromellitic acid, anhydrides of these acids, and alkyl esters of these acids with 1 to 3 carbon atoms.

[0038] The alcohol component may contain a monohydric alcohol, and the carboxylic acid component may contain a monohydric carboxylic acid compound, as appropriate.

[0039] In this specification, macromonomers and hydroxycarboxylic acids are not included in the alcohol and carboxylic acid components.

[0040] In addition, polyethylene terephthalate (PET) may be used along with the alcohol and carboxylic acid components. Ethylene glycol and terephthalic acid produced by the depolymerization of PET, or a portion thereof, are used as raw material monomers in a polycondensation reaction and incorporated into the polyester resin. PET is an equimolar polycondensate of ethylene glycol and terephthalic acid, and in this specification, unless otherwise specified, ethylene glycol and terephthalic acid constituting PET are calculated as the alcohol and carboxylic acid components, respectively.

[0041] PET can be either new PET (virgin PET) or recycled PET. Recycled PET refers to material obtained by collecting used PET, washing it as needed, separating it from other materials, crushing it, depolymerizing the crushed material to monomer units, and then resynthesizing it using these monomers as raw materials.

[0042] In this invention, it is preferable that the PET has a relatively low IV value, i.e., a low molecular weight, compared to conventionally used PET. By introducing low IV value (low molecular weight) PET into the polyester resin, the depolymerization of PET proceeds more uniformly.

[0043] From the viewpoint of the above, the IV value of PET is preferably 0.40 or higher, more preferably 0.45 or higher, even more preferably 0.50 or higher, and even more preferably 0.55 or higher. From the viewpoint of low-temperature fixability and homogenization of depolymerization, it is preferably 0.85 or lower, more preferably 0.75 or lower, and even more preferably 0.70 or lower. The IV value is the intrinsic viscosity and serves as an indicator of molecular weight. The IV value of PET can be adjusted by the polycondensation time, etc.

[0044] Commercially available PET products with 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). Among these, UK-31 is preferred.

[0045] The content of 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 100% by mass or less, of the total amount of PET subjected to polycondensation.

[0046] If PET is included, the PET content is preferably 5 mol% or more, more preferably 15 mol% or more, even more preferably 25 mol% or more, and preferably 50 mol% or less, more preferably 40 mol% or less, and even more preferably 30 mol% or less, from the viewpoint of low-temperature fixability. Since PET is a polycondensate of ethylene glycol, terephthalic acid, dimethyl terephthalate, etc., the terephthalic acid-ethylene glycol unit (Mw: 192) is considered 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.

[0047] Amorphous polyester resin A 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 optionally in the presence of a co-catalyst, polymerization inhibitor, etc., at a temperature preferably 130°C or higher, more preferably 170°C or higher, and preferably 250°C or lower, more preferably 240°C or lower.

[0048] Examples of esterification catalysts include tin compounds such as dibutyltin oxide and tin(II) 2-ethylhexanoate, and titanium compounds such as titanium diisopropoxybis(triethanolamine) and titanium dihydroxybis(triethanolamine). The amount of 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, and more preferably 1 part by mass or less, per 100 parts by mass of the total amount of alcohol and carboxylic acid components. Examples of co-catalysts for the esterification catalyst include gallic acid. The amount of 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, and more preferably 0.1 parts by mass or less, per 100 parts by mass of the total amount of alcohol and carboxylic acid components. Examples of polymerization inhibitors include tert-butylcatechol. The amount of polymerization inhibitor 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, and more preferably 0.1 parts by mass or less, based on 100 parts by mass of the total amount of alcohol and carboxylic acid components.

[0049] In this invention, the polyester resin may be a polyester resin that has been modified to such an extent that its properties are not substantially impaired. Examples of modified polyester resins include polyester resins that have been grafted or blocked with phenol, urethane, epoxy, etc., by methods described in Japanese Patent Publication No. 11-133668, Japanese Patent Publication No. 10-239903, Japanese Patent Publication No. 8-20636, etc. Among modified polyester resins, urethane-modified polyester resins obtained by urethane elongation of polyester resin with a polyisocyanate compound are preferred.

[0050] The softening point of amorphous polyester resin A is preferably 90°C or higher, more preferably 100°C or higher, from the viewpoint of electrostatic stability, and preferably 150°C or lower, more preferably 140°C or lower, from the viewpoint of low-temperature fixability.

[0051] The crystallinity of a resin is expressed by a crystallinity index, which is defined by 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]. The amorphous resin is one in which no endothermic peak is observed, or, if observed, a resin with a crystallinity index 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. On the other hand, the crystalline resin is a resin having 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. The crystallinity of a resin can be adjusted by the type and ratio of raw material monomers, as well as the manufacturing conditions (e.g., reaction temperature, reaction time, cooling rate). The maximum endothermic peak temperature refers to the temperature of the peak with the largest peak area among the observed endothermic peaks. In crystalline resins, the maximum endothermic peak temperature is defined as the melting point.

[0052] The glass transition temperature of amorphous polyester resin A is preferably 40°C or higher, more preferably 50°C or higher, from the viewpoint of storage properties, and preferably 80°C or lower, more preferably 75°C or lower, from the viewpoint of low-temperature fixation properties.

[0053] The acid value of amorphous polyester resin A is preferably 5 mg KOH / g or more, more preferably 10 mg KOH / g or more, from the viewpoint of electrostatic stability, and preferably 50 mg KOH / g or less, more preferably 40 mg KOH / g or less, from the viewpoint of low-temperature fixability.

[0054] The hydroxyl value of amorphous polyester resin A is preferably 10 mg KOH / g or more, more preferably 15 mg KOH / g or more, from the viewpoint of electrostatic stability, and preferably 40 mg KOH / g or less, more preferably 30 mg KOH / g or less, from the viewpoint of low-temperature fixability.

[0055] The content of amorphous polyester resin A in the binder resin composition is preferably 80% by mass or more, more preferably 85% by mass or more, and preferably 99% by mass or less, more preferably 95% by mass or less, and even more preferably 90% by mass or less.

[0056] The crystalline polyester resin C is preferably a polycondensate of an alcohol component containing an aliphatic diol and a carboxylic acid component containing an aliphatic dicarboxylic acid compound, more preferably a polycondensate of an alcohol component containing an aliphatic diol having 2 to 6 carbon atoms and a carboxylic acid component containing an aliphatic dicarboxylic acid compound having 10 to 14 carbon atoms, and even more preferably a polycondensate of an alcohol component containing ethylene glycol and a carboxylic acid component containing an aliphatic dicarboxylic acid compound having 10 to 14 carbon atoms.

[0057] Examples of aliphatic diols include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,4-butenediol, 1,7-heptanediol, 1,8-octanediol, neopentyl glycol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, and 1,12-dodecanediol.

[0058] The aliphatic diol has 2 or more carbon atoms, and from the viewpoint of low-temperature fixability, it is preferably 12 or less, more preferably 10 or less, even more preferably 6 or less, and even more preferably 4 or less.

[0059] From the viewpoint of improving the low-temperature fixability of the toner, aliphatic diols are preferably those having a hydroxyl group at the end of the carbon chain, and more preferably α,ω-linear alkanediols.

[0060] The content of aliphatic diols, preferably aliphatic diols having 2 to 6 carbon atoms, and more preferably ethylene glycol, is preferably 80 mol% or more, more preferably 90 mol% or more, even more preferably 95 mol% or more, and 100 mol% or less, in the alcohol component.

[0061] Examples of alcohol components other than aliphatic diols include alkylene oxide adducts of bisphenol A, aromatic diols such as bisphenol A, hydrogenated bisphenol A, alicyclic diols such as 1,4-cyclohexanedimethanol, and trivalent or higher alcohols such as sorbitol, pentaerythritol, glycerin, and trimethylolpropane.

[0062] Examples of aliphatic dicarboxylic acid compounds include succinic acid (4 carbon atoms), fumaric acid (4 carbon atoms), adipic acid (6 carbon atoms), suberic acid (8 carbon atoms), azelaic acid (9 carbon atoms), sebacic acid (10 carbon atoms), dodecanediic acid (12 carbon atoms), tetradecanediic acid (14 carbon atoms), anhydrides of these acids, and alkyl esters of these acids with 1 to 3 carbon atoms.

[0063] From the viewpoint of preservation, the carbon number of the aliphatic dicarboxylic acid compound is preferably 10 or more, and from the viewpoint of low-temperature fixability, it is preferably 14 or less, more preferably 12 or less. Here, the carbon number of the alkyl group when the aliphatic dicarboxylic acid compound is an alkyl ester is not included in the above carbon number.

[0064] The content of the aliphatic dicarboxylic acid compound is preferably 80 mol% or more, more preferably 90 mol% or more, even more preferably 95 mol% or more, and 100 mol% or less, of the carboxylic acid component.

[0065] 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.

[0066] The alcohol component may contain a monohydric alcohol, and the carboxylic acid component may contain a monohydric carboxylic acid compound, as appropriate.

[0067] The equivalent ratio of the carboxyl group of the carboxylic acid component to the hydroxyl group of the alcohol component (COOH group / OH group) is preferably 0.8 or higher, more preferably 0.9 or higher, from the viewpoint of electrostatic stability, and preferably 1.2 or lower, more preferably 1.1 or lower, from the viewpoint of low-temperature fixability.

[0068] The polycondensation reaction conditions between the alcohol component and the carboxylic acid component of crystalline polyester resin C are the same as those for amorphous polyester resin A, except that the preferred reaction temperature is 120°C or higher, more preferably 180°C or higher, and 230°C or lower, more preferably 220°C or lower.

[0069] 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 low-temperature fixability, and preferably 140°C or lower, more preferably 120°C or lower, and even more preferably 100°C or lower.

[0070] The melting point of the crystalline polyester resin C is preferably 45°C or higher, more preferably 60°C or higher, and even more preferably 65°C or higher, from the viewpoint of low-temperature fixability, and preferably 130°C or lower, more preferably 120°C or lower, and even more preferably 90°C or lower.

[0071] The acid value of the crystalline polyester resin C is preferably 2 mg KOH / g or more, more preferably 3 mg KOH / g or more, from the viewpoint of low-temperature fixability, and preferably 30 mg KOH / g or less, more preferably 20 mg KOH / g or less, from the viewpoint of durability.

[0072] The hydroxyl value of the crystalline polyester resin C is preferably 5 mg KOH / g or more, more preferably 10 mg KOH / g or more, from the viewpoint of low-temperature fixability, and preferably 30 mg KOH / g or less, more preferably 20 mg KOH / g or less, from the viewpoint of durability.

[0073] The content of crystalline polyester resin C in the binder resin composition is preferably 1% by mass or more, more preferably 5% by mass or more, and even more preferably 10% by mass or more, from the viewpoint of low-temperature fixation, and preferably 20% by mass or less, and more preferably 15% by mass or less, from the viewpoint of durability.

[0074] The mass ratio of crystalline polyester resin C to amorphous polyester resin A (crystalline polyester resin C / amorphous polyester resin A) is preferably 1 / 99 or more, more preferably 5 / 95 or more, even more preferably 10 / 90 or more, and preferably 20 / 80 or less, more preferably 15 / 85 or less, from the viewpoint of low-temperature fixability.

[0075] The mass ratio of polymerized rosin contained in the carboxylic acid component of amorphous polyester resin A to crystalline polyester resin C (polymerized rosin / crystalline polyester resin C) is preferably 0.3 or higher, more preferably 0.5 or higher, even more preferably 1.0 or higher, and preferably 5.0 or lower, more preferably 3.0 or lower, and even more preferably 2.0 or lower, from the viewpoint of durability under high humidity.

[0076] The total content of amorphous polyester resin A and crystalline polyester resin C in the binder resin composition is preferably 80% by mass or more, more preferably 90% by mass or more, even more preferably 95% by mass or more, and 100% by mass or less.

[0077] Other resins include vinyl resins such as styrene-acrylic resin, polyamide resin, epoxy resin, polycarbonate resin, polyurethane resin, and composite resins containing two or more of these resins.

[0078] Furthermore, the present invention provides a toner for electrostatic image development that contains the toner binder resin composition of the present invention as a binder resin (binding agent).

[0079] The content of the binder resin composition in the toner is preferably 60% by mass or more, more preferably 70% by mass or more, and preferably less than 100% by mass, more preferably 95% by mass or less, and even more preferably 93% by mass or less.

[0080] The toner of the present invention may contain additives other than the binder resin (binder resin composition), such as colorants, release agents, charge control agents, magnetic powders, flowability improvers, conductivity modifiers, reinforcing fillers such as fibrous materials, antioxidants, and cleaning properties improvers.

[0081] As colorants, dyes, pigments, magnetic materials, etc., used as colorants for toners can be used. Examples include carbon black, phthalocyanine blue, permanent brown FG, brilliant first 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 this invention, the toner may be either black toner or color toner.

[0082] From the viewpoint of improving the toner's image density and low-temperature fixability, the colorant content 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, per 100 parts by mass of the binder resin composition.

[0083] Examples of mold release agents include hydrocarbon waxes and their oxides, such as polypropylene wax, polyethylene wax, ethylene propylene copolymer wax, microcrystalline wax, paraffin wax, and Fischer-Tropsch wax; ester waxes such as carnauba wax, montane wax and their deoxidizing waxes, and fatty acid ester waxes; and fatty acid amides, fatty acids, higher alcohols, fatty acid metal salts, etc., which can be used individually or in combination of two or more.

[0084] 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 preferably 160°C or lower, more preferably 140°C or lower, and even more preferably 120°C or lower, from the viewpoint of low-temperature fixation.

[0085] The release agent content is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, even more preferably 1.5 parts by mass or more, and 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, from the viewpoint of low-temperature fixation and offset resistance of the toner and dispersibility in the binder resin composition, per 100 parts by mass of the binder resin composition.

[0086] The charge control agent is not particularly limited and may contain either a positively charged charge control agent or a negatively charged charge control agent.

[0087] Positively charged 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, Ltd.); triphenylmethane-based dyes containing tertiary amines as side chains; quaternary ammonium salt compounds, such as "Bontron P-51" (manufactured by Orient Chemical Industries, Ltd.), cetyltrimethylammonium bromide, and "COPY CHARGE PX." Examples include VP435 (manufactured by Clariant), polyamine resins such as AFP-B (manufactured by Orient Chemical Industries, Ltd.), imidazole derivatives such as PLZ-2001 and PLZ-8001 (both manufactured by Shikoku Chemicals, Ltd.), and styrene-acrylic resins such as FCA-701PT and FCA-201-PS (manufactured by Fujikura Chemicals, Ltd.).

[0088] Furthermore, as negative charge control agents, 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.), "Eisenspiron Black TRH," and "T-77" (manufactured by Hodogaya Chemical Co., Ltd.); metal compounds of benzyl acid compounds, such as "LR-147" and "LR-297" (both 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" Examples include VP434 (manufactured by Clariant), nitroimidazole derivatives, organometallic compounds, etc.

[0089] From the viewpoint of the charge control 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, per 100 parts by mass of the binder resin composition.

[0090] The toner of the present invention may be obtained by any of the conventionally known methods, such as the melt-kneading method, the emulsification-coagulation method, or the suspension polymerization method, and may also be a toner having a core-shell structure. However, from the viewpoint of the mixability of the toner raw materials, pulverized toner is preferred, and pulverized toner obtained by the melt-kneading method, that is, pulverized toner obtained by a method including the steps of melt-kneading the raw materials and pulverizing the resulting mixture, is more preferred. Specifically, for example, raw materials such as a binder resin composition, a colorant, a release agent, and a charge control agent can be uniformly mixed in a mixer such as a Henschel mixer, then melt-kneaded in a closed-type kneader, a single-screw or twin-screw extruder, an open-roll type kneader, etc., and then cooled, pulverized, and classified to produce the toner. In the production of the toner, a binder resin composition in which amorphous polyester resin A and crystalline polyester resin C are pre-mixed may be used, or these resins may be directly used in the mixing of raw materials when producing the toner.

[0091] In the toner of the present invention, it is preferable to use an external additive to improve fluidity. Examples of external additives include inorganic fine particles such as silica, alumina, titania, zirconia, tin oxide, and zinc oxide, and organic fine particles such as melamine resin fine particles and polytetrafluoroethylene resin fine particles, and two or more may be used in combination. Among these, silica is preferred, and from the viewpoint of toner fluidity, hydrophobic silica that has been hydrophobicized is more preferred.

[0092] Examples of hydrophobic agents used to hydrophobize the surface of silica particles include hexamethyldisilazane (HMDS), dimethyldichlorosilane (DMDS), cyclic silazane, silicone oil, aminosilane, octyltriethoxysilane (OTES), and methyltriethoxysilane.

[0093] The average particle size of the external additive is preferably 10 nm or larger, more preferably 250 nm or smaller, more preferably 200 nm or smaller, and even more preferably 90 nm or smaller, from the viewpoint of the toner's chargeability, fluidity, and transferability.

[0094] External additive treatment, which involves mixing toner particles with external additives, can be carried out according to conventional methods, and a mixer such as a Henschel mixer can be used.

[0095] From the viewpoint of the toner's electrostatic properties, fluidity, and transferability, the content of the external additive is preferably 0.05 parts by mass or more, more preferably 0.1 parts by mass or more, even more preferably 0.3 parts by mass or more, and preferably 5 parts by mass or less, and more preferably 4 parts by mass or less, per 100 parts by mass of toner particles before treatment with the external additive.

[0096] The volume-intermediate particle size (D) of the toner of the present invention 50 The volume median particle size (D) is preferably 3 μm or more, more preferably 4 μm or more, and preferably 15 μm or less, more preferably 10 μm or less. 50 ) refers to the particle size at which the cumulative volume frequency, calculated using volume fractions, accounts for 50% of the total volume frequency, starting from the smallest particle size. Furthermore, if the toner is treated with an external additive, the volume median particle size of the toner particles before treatment with the external additive is considered the volume median particle size of the toner.

[0097] The toner of the present invention can be used as is as a one-component developing toner, or as a two-component developing toner mixed with a carrier, in image forming apparatuses using either a one-component developing method or a two-component developing method, respectively. [Examples]

[0098] The present invention will be specifically described below with reference to examples, but the present invention is not limited in any way by these examples. The physical properties of resins, etc., can be measured by the following methods.

[0099] [Composition of polymerized rosin] Polymerized rosin is analyzed by gel permeation chromatography (GPC). GPC is performed using "HLC-8220" (manufactured by Tosoh Corporation) with a "Tskgel column" (manufactured by Tosoh Corporation) as the column, tetrahydrofuran (THF) as the solvent, and a flow rate of 1.0 ml / min. The peak area ratio of each component obtained is defined as the composition ratio of polymers (rosin trimers or more), rosin dimers, rosin acids, and rosin esters (rosin monomers).

[0100] [Composition of rosin dimer] Rosin dimers contained in polymerized rosin are analyzed by gas chromatography-mass spectrometry (GC-MS). Agilent Technologies' Agilent 7890A (GC) and Agilent 5975 (MS) GC-MS systems are used, with an Agilent Technologies DB-5MS column. Polymerized rosin compounds are dissolved in a 1:1 (volume ratio) mixed solution of toluene and methanol, derivatized by methyl ester, and then measured. Bifunctional rosin dimers are identified as all peaks at m / z; 632 detected between retention times of 27 and 34 minutes. Monofunctional rosin dimers are identified as all peaks at m / z; 574 detected between retention times of 24 and 32 minutes. Rosin dimers without functional groups are identified as all peaks at m / z; 520 detected between retention times of 23 and 27 minutes.

[0101] [PET IV value] The phenol / tetrachloroethane is dissolved at a concentration of 4 g / L in a 60 / 40 (mass ratio) mixed solvent, and the concentration is measured using an Ubbelohde viscometer and calculated using the following formula. IV = (-1 + √(1 + 4kη)) / (2kC) [In the formula, k = 0.33, C = 0.004 g / mL, and η = (t1 / t0) - 1 (t0: number of seconds for the solvent to fall, t1: number of seconds for the sample solution to fall).]

[0102] [Softening point of resin] Using a flow tester "CFT-500D" (manufactured by Shimadzu Corporation), 1 g of sample is heated at a heating rate of 6°C / min while a load of 1.96 MPa is applied by a plunger, and the sample is extruded from a nozzle with a diameter of 1 mm and a length of 1 mm. The amount of plunger descent of the flow tester is plotted against temperature, and the temperature at which half of the sample has flowed out is defined as the softening point.

[0103] [Maximum peak temperature of endothermic resin] Using a differential scanning calorimeter "Q-100" (manufactured by T.A. Instruments Japan Co., Ltd.), 0.01 to 0.02 g of the sample is weighed into an aluminum pan and 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 taken at a rate of 10°C / min. Among the observed endothermic peaks, the temperature of the peak with the largest peak area is defined as the maximum endothermic peak temperature. For crystalline resins, the maximum endothermic peak temperature is defined as the melting point.

[0104] [Glass transition temperature of resins] Using a differential scanning calorimeter "Q-100" (manufactured by T.A. Instruments Japan Co., Ltd.), 0.01 to 0.02 g of the sample is weighed into an aluminum pan and heated from room temperature (20°C) to 200°C at a heating rate of 10°C / min, and then cooled to 0°C at a cooling rate of 10°C / min. Next, the sample is heated at a heating rate of 10°C / min and the endothermic peak is measured. The temperature at the intersection of the extension of the baseline below the maximum endothermic peak temperature and the tangent line showing the maximum slope from the rising part of the peak to the peak apex is defined as the glass transition temperature.

[0105] [Acid value of resins] Measurements will be performed according to the method of JIS K 0070:1992. However, the measurement solvent will be changed from the ethanol and ether mixed solvent specified in JIS K 0070 to an acetone and toluene mixed solvent (acetone:toluene = 1:1 (volume ratio)) for amorphous resins, and to tetrahydrofuran for crystalline resins.

[0106] [Hydroxyl value of resins] The measurement will be performed according to the method of JIS K 0070:1992. However, the measurement solvent will be changed from the mixed solvent of ethanol and ether specified in JIS K 0070 to tetrahydrofuran.

[0107] [Melting point of release agent] Using a differential scanning calorimeter "Q-100" (manufactured by T.A. Instruments Japan Co., Ltd.), 0.02 g of the sample is weighed into an aluminum pan, heated to 200°C, and then cooled from 200°C to 0°C at a rate of 10°C / min. Next, the sample is heated at a rate of 10°C / min and the heat quantity is measured, with the maximum endothermic peak temperature being defined as the melting point.

[0108] [Average particle size of external additives] The average particle diameter refers to the number-average particle diameter, which is calculated by measuring the particle size (average of the major and minor axes) of 500 particles from scanning electron microscope (SEM) images and using the number-average value of these measurements.

[0109] [Medium particle size in toner volume] • Measuring instrument: "Coulter Multisizer (Registered Trademark) III" (manufactured by Beckman Coulter, Inc.) • Aperture diameter: 100 μm • Analysis software: "Multisizer III (registered trademark) Version 3.51" (manufactured by Beckman Coulter, Inc.) • Electrolyte: "Isoton (registered trademark) II" (manufactured by Beckman Coulter, Inc.) • Dispersion: Prepared by dissolving polyoxyethylene lauryl ether "Emulgen (registered trademark) 109P" [manufactured by Kao Corporation, HLB (Griffin) = 13.6] in the electrolyte to adjust the concentration to 5% by mass. • Dispersion conditions: Add 10 mg of the sample to 5 mL of the dispersion and disperse for 1 minute using an ultrasonic disperser (machine name: US-1 manufactured by SND Corporation, output: 80W). Then, add 25 mL of electrolyte and disperse for another minute using the ultrasonic disperser to prepare the sample dispersion. • Measurement conditions: The sample dispersion is added to 100 mL of the electrolyte to adjust the concentration so that the particle size of 30,000 particles can be measured in 20 seconds. Then, the 30,000 particles are measured, and the volume median particle size (D) is determined from the particle size distribution. 50 )

[0110] Resin manufacturing example 1 The alcohol components, carboxylic acid components other than trimellitic anhydride, and esterification catalyst shown in Table 1 were placed in a 10-liter four-necked flask equipped with a thermometer, stainless steel stirring rod, a drop-flow condenser with a dehydration tube, and a nitrogen inlet tube. The mixture was heated in a mantle heater under a nitrogen atmosphere from 180°C to 230°C over 6 hours, and the reaction was carried out at 230°C for 3 hours. After that, trimellitic anhydride was added, and the reaction was carried out at 220°C at 8.0 kPa until the softening point shown in Table 1 was reached to obtain amorphous polyester resins (resins A1, A3, A4, A6, A7, A8).

[0111] Resin manufacturing example 2 The alcohol components, carboxylic acid components other than trimellitic anhydride, and esterification catalyst shown in Table 1 were placed in a 10-liter four-necked flask equipped with a thermometer, stainless steel stirring rod, a drop-flow condenser with a dehydration tube, and a nitrogen inlet tube. The mixture was reacted at 230°C for 5 hours in a mantle heater under a nitrogen atmosphere. Subsequently, trimellitic anhydride was added, and the reaction was carried out at 220°C and 8.0 kPa until the softening point shown in Table 1 was reached, yielding amorphous polyester resin (resin A2).

[0112] Resin manufacturing example 3 The alcohol components, carboxylic acid components other than trimellitic anhydride, PET, and esterification catalyst shown in Table 1 were placed in a 10-liter four-necked flask equipped with a thermometer, stainless steel stirring rod, a drop-flow condenser with a dehydration tube, and a nitrogen inlet tube. The mixture was heated in a mantle heater under a nitrogen atmosphere from 180°C to 230°C over 6 hours, and the reaction was carried out at 230°C for 3 hours. After that, trimellitic anhydride was added, and the reaction was carried out at 220°C at 8.0 kPa until the softening point shown in Table 1 was reached, yielding amorphous polyester resin (resin A5).

[0113] The polymerized rosin "CP-140" (manufactured by Arakawa Chemical Industries, Ltd.) used had a composition of 35% by mass of rosin monomer, 55% by mass of rosin dimer, and 7% by mass of rosin trimer. The composition of the rosin dimer was 79% by mass of bifunctional rosin dimer, 20% by mass of monofunctional rosin dimer, and 1% by mass of rosin dimer without functional groups. Therefore, the content of bifunctional rosin dimer in the polymerized rosin was 43% by mass. The rosin "Shiragiku Rosin" (manufactured by Arakawa Chemical Industries, Ltd.) is a purified rosin obtained by refining natural rosin and does not contain rosin polymers.

[0114] [Table 1]

[0115] Resin manufacturing example 4 The alcohol and carboxylic acid components shown in Table 2 were placed in a 10-liter four-necked flask equipped with a thermometer, stainless steel stirring rod, a fall-flow condenser, and a nitrogen inlet tube. The mixture was then heated to 200°C over 8 hours in a mantle heater under a nitrogen atmosphere. Subsequently, an esterification catalyst was added, and the reaction was carried out at 8 kPa until the softening point shown in Table 2 was reached, yielding crystalline polyester resins (resins C1 and C2).

[0116] [Table 2]

[0117] Examples 1-8 and Comparative Examples 1-4 The following mixtures were thoroughly mixed in a Henschel mixer: 100 parts by mass of the binder resin shown in Table 3, 5 parts by mass of the coloring agent "ECB-301" (manufactured by Dainichi Seika Kogyo Co., Ltd., phthalocyanine blue), 1 part by mass of the charge control agent "LR-147" (manufactured by Nippon Carlit Co., Ltd.), 2 parts by mass of the release agent "Carnauba Wax C1" (manufactured by Kato Yoko Co., Ltd., melting point: 80°C), and 2 parts by mass of the release agent "Paraflint H105" (manufactured by Sazol Co., Ltd., Fischer-Tropsch wax, melting point: 110°C). The mixtures were then melt-kneaded using a co-rotating twin-screw extruder with a total mixing section length of 1560 mm, a screw diameter of 42 mm, and a barrel inner diameter of 43 mm. The screw rotation speed was 200 r / min, the heating setting temperature in the rolls was 100°C, the temperature of the kneaded material was 160°C, the feed rate of the kneaded material was 10 kg / h, and the average residence time was approximately 18 seconds.

[0118] The resulting mixture was cooled and then coarsely ground to a size of 2 mm or less using a Rotoplex pulverizer (manufactured by Hosokawa Micron Corporation) with a sieve with a mesh size of 2 mm.

[0119] The obtained coarse pulverized material was finely pulverized using an IDS2 type pulverizer manufactured by Nippon Pneumatic Mfg. Co., Ltd. The pulverizer conditions were as follows: the impact member was replaced with a semi-cylindrical impact member obtained by cutting a cylinder with a radius of 10 mm as its base perpendicular to the base and then halving it; the pulverizing air pressure was adjusted to 0.5 MPa; and the distance between the impact plate and the nozzle was adjusted to 20 mm. The resulting toner particle size (D) was the median particle size (D) by volume. 50 The raw material feed amount was adjusted and the material was ground so that the particle size was 6 μm and the CV value was 22.

[0120] Toner was obtained by adding 1 part by mass of hydrophobic silica "AEROSIL NAX 50" (manufactured by Nippon Aerosil Co., Ltd., hydrophobic treatment agent: HMDS, average particle size: approximately 30 nm) as an external additive to 100 parts by mass of the obtained toner particles and mixing them in a Henschel mixer.

[0121] Test Example 1 [Gross] The fuser unit of the "AR-505" copier (manufactured by Sharp Corporation) has been modified to allow for external fixing, and toner has been installed in this modified unit. 2 An unfixed image of solid color, 4cm x 4cm, was obtained on the above. Using a modified external fixing device, the "DL-2300" (manufactured by Konica Minolta, Inc.), an oil-less fixing method external fixing device was used. The fixing process was performed with the fixing roll rotation speed set to 265 mm / sec and the fixing roll temperature in the fixing device set to 160°C, and a fixed image was obtained. The glossiness of the fixed image was measured. The glossiness was measured using a gloss meter "PG-1" (manufactured by Nippon Denshoku Industries, Ltd.), with the light source set to 60°, and the gloss was evaluated. The results are shown in Table 3. A higher glossiness indicates better gloss.

[0122] Test Example 2 [Durability under high humidity conditions] Toner was installed in a "PagePresto N-4" laser printer (manufactured by Casio Computer Co., Ltd., fixing method: contact fixing method, developing method: non-magnetic one-component developing method, developing roll diameter: 2.3 cm), and a diagonal stripe pattern with a blackening rate of 5.5% was continuously printed under conditions of 40°C and 80% relative humidity. Every 500 sheets, a solid black image was printed, and streaks were checked on the image. The number of printed sheets up to the point where streaks were visually observed on the image was considered the number of sheets where streaks occurred due to toner fusion and adhesion to the developing roll, and durability was evaluated according to the following evaluation criteria. The results are shown in Table 3. A higher number of sheets with streaks indicates better toner durability.

[0123] [Table 3]

[0124] From these results, it can be seen that the toners of Examples 1 to 8 have high gloss and good durability under high humidity conditions. In contrast, the toners of Comparative Examples 1 and 2, which contain amorphous polyester resin without polymerized rosin, have low gloss and poor durability. Furthermore, the toner of Comparative Example 3, which does not contain crystalline polyester resin, has good durability but low gloss, and the toner of Comparative Example 4, which contains amorphous polyester resin with excessive polymerized rosin, has high gloss but poor durability. [Industrial applicability]

[0125] The toner for electrostatic image development containing the toner binder resin composition of the present invention is suitably used for developing latent images formed in electrostatic image development methods, electrostatic recording methods, electrostatic printing methods, and the like.

Claims

1. A binder resin composition for toner containing amorphous polyester resin A and crystalline polyester resin C, wherein the amorphous polyester resin A is a polycondensate of an alcohol component and a carboxylic acid component containing polymerized rosin, and the content of the polymerized rosin is 2% by mass or more and 40% by mass or less of the carboxylic acid component.

2. The binder resin composition for toner according to claim 1, wherein the crystalline polyester resin C is a polycondensate of an alcohol component containing an aliphatic diol having 2 to 6 carbon atoms and a carboxylic acid component containing an aliphatic dicarboxylic acid compound having 10 to 14 carbon atoms.

3. The toner binder resin composition according to claim 1, 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 having 10 to 14 carbon atoms.

4. A binder resin composition for toner according to any one of claims 1 to 3, wherein the mass ratio of crystalline polyester resin C to amorphous polyester resin A is 1 / 99 or more and 20 / 80 or less.

5. A binder resin composition for toner according to any one of claims 1 to 3, wherein the carboxylic acid component of amorphous polyester resin A further contains an aromatic dicarboxylic acid compound.

6. The toner binder resin composition according to claim 5, wherein the mass ratio of the aromatic dicarboxylic acid compound to the polymerized rosin is 1.0 or more and 20 or less.

7. A toner for developing electrostatic images, comprising the toner binder resin composition according to any one of claims 1 to 3.

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