Binder resin composition for toner

Abstract

To provide a binder resin composition for a toner which is excellent in crushability and scratch resistance of a printed matter, and a toner for electrostatic charge image development containing the binder resin composition.SOLUTION: There are provided a binder resin composition for a toner which contains an amorphous polyester resin A that is a polycondensation product of an alcohol component and a carboxylic acid component, wherein a number average molecular weight of the amorphous polyester resin A is 3,000 or more, and a loss tangent at 50°C of 0.20 or less, and the carboxylic acid component contains 3 mol% or more and 25 mol% or less of an aliphatic dicarboxylic acid-based compound, and 2 mol% or more and 15 mol% or less of an aliphatic monocarboxylic acid-based compound; and a toner for electrostatic charge image development containing the binder resin composition.SELECTED DRAWING: None

Description

[Technical field]

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

[0002] In the field of electrophotography, with the development of electrophotographic systems, there is a demand for the development of toners for developing electrostatic images (hereinafter, simply referred to as "toners") that can meet the demands of higher image quality and higher speeds. For example, as the machine speed increases, the amount of heat applied to the toner applied to the recording paper during fixing decreases, and therefore toners are required to have better low-temperature fixing properties. In addition, by lowering the minimum fixing temperature and increasing the temperature at which high-temperature offset occurs, the fixing temperature range can be expanded, and the demands for higher image quality can be met by saving energy and suppressing the occurrence of high-temperature offset. Therefore, there is a high demand for binder resins for toners and toners that have a wide fixing temperature range.

[0003] On the other hand, polyester resins using monovalent aliphatic alcohols or aliphatic carboxylic acids having relatively long carbon chains as raw material monomers have been reported as binder resins with excellent fixing and electrostatic properties (see Patent Documents 1 to 3). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP2015-52103A [Patent Document 2] International Publication No. 2010 / 143385 [Patent Document 3] JP 2007-58135 A Summary of the Invention [Problem to be solved by the invention]

[0005] Generally, a toner binder resin having excellent low-temperature fixing property has excellent grindability and high toner productivity, but has low high-temperature offset resistance and insufficient abrasion resistance of printed matter. On the other hand, a toner binder resin having a high high-temperature offset occurrence temperature has excellent abrasion resistance of printed matter, but has poor grindability and low toner productivity.

[0006] It is known that high-temperature offset resistance can be improved by increasing the molecular weight of the binder resin. On the other hand, increasing the molecular weight of the binder resin is also effective in improving the abrasion resistance, but increasing the molecular weight of the binder resin deteriorates the grindability and reduces the productivity.

[0007] Therefore, there is a high demand for a binder resin for toner and a toner that are excellent in grindability and in abrasion resistance of printed matter.

[0008] However, it has been found that the binder resins for toners disclosed in Patent Documents 1 and 2 have excellent low-temperature fixing properties and pulverizability, but the abrasion resistance of printed matter is insufficient. Also, it has been found that the binder resin for toners disclosed in Patent Document 3 has excellent low-temperature fixing properties and high-temperature offset resistance, but the pulverizability is insufficient.

[0009] The present invention relates to a binder resin composition for toners, which has excellent grindability and excellent abrasion resistance of printed matter, and to a toner for developing electrostatic images, which contains the binder resin composition. [Means for solving the problem]

[0010] The present invention relates to [1] A binder resin composition for toners, which contains an amorphous polyester resin A that is a polycondensation product of an alcohol component and a carboxylic acid component, the amorphous polyester resin A having a number average molecular weight of 3,000 or more and a loss tangent at 50° C. of 0.20 or less, and the carboxylic acid component containing an aliphatic dicarboxylic acid compound in an amount of 3 mol % to 25 mol % and an aliphatic monocarboxylic acid compound in an amount of 2 mol % to 15 mol %, and [2] A toner for developing electrostatic images, comprising the binder resin composition for toners according to [1] above. Regarding. Effect of the Invention

[0011] The binder resin composition for toner of the present invention exhibits excellent effects in terms of pulverizability and abrasion resistance of printed matter. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] In the binder resin composition for toner of the present invention (hereinafter, also simply referred to as "binder resin"), the amorphous polyester resin A has a high molecular weight of 3,000 or more, but does not impair grindability and provides excellent abrasion resistance of printed matter. The reason why the effects of the present invention are achieved is not clear, but is presumed to be as follows.

[0013] Conventionally, when the number average molecular weight (Mn) of an amorphous polyester resin is 3,000 or more, the molecular chains are more entangled and the cohesive force is stronger, which results in high high-temperature offset resistance and improved abrasion resistance of printed matter. On the other hand, the grindability is lowered, which reduces the productivity of the toner. However, as a result of investigations conducted by the present inventors, it was found that even for amorphous polyester resins with high molecular weights (Mn≧3,000), the grindability tends to be improved by controlling the loss tangent (tan δ) at 50°C to 0.20 or less. Amorphous resins have low viscosity due to the high intermolecular forces between molecular chains below the glass transition temperature (Tg), and because this depends on the elasticity of the molecular chains, the loss tangent (tan δ) (≒viscosity contribution / elasticity contribution) becomes smaller as the elasticity contribution increases. Therefore, controlling tan δ to a low value improves crushability, meaning that the harder the molecular chains are, the easier they are to break. In the present invention, it was found that by using an aliphatic dicarboxylic acid compound as the carboxylic acid component of the amorphous polyester resin to increase the molecular weight, a hard molecular chain with a loss tangent (tan δ) of 0.20 or less was obtained, and further, by using an aliphatic monocarboxylic acid compound, the grindability was dramatically improved even in the case of a high molecular weight (Mn≧3,000). It is believed that the polarity difference between the molecular chains increases when a molecular chain with an aliphatic monocarboxylic acid compound introduced therein and a small amount of molecular chains without an aliphatic monocarboxylic acid compound introduced therein are mixed in the resin, and therefore the cohesive force between the molecular chains is locally reduced, and the grindability is dramatically improved.

[0014] The amorphous polyester resin A is a polycondensation product of an alcohol component and a carboxylic acid component.

[0015] As the alcohol component, from the viewpoint of low temperature fixability, a compound represented by the formula (I):

[0016] [ka]

[0017] (In the formula, OR and RO are oxyalkylene groups, R is an ethylene group and / or a propylene group, x and y are the average number of moles of alkylene oxide added, each of which is a positive number, and the sum of x and y is 1 or more, preferably 1.5 or more, and 16 or less, preferably 8 or less, more preferably 6 or less, and even more preferably 4 or less.) The alkylene oxide adduct of bisphenol A represented by formula (I) is preferably a compound represented by the formula (I). Examples of the alkylene oxide adduct of bisphenol A represented by formula (I) include a polyoxypropylene adduct of 2,2-bis(4-hydroxyphenyl)propane, a polyoxyethylene adduct of 2,2-bis(4-hydroxyphenyl)propane, etc. It is preferable to use one or more of these.

[0018] The content of the alkylene oxide adduct of bisphenol A represented by formula (I) in the alcohol component is preferably 60 mol % or more, more preferably 70 mol % or more, and even more preferably 80 mol % or more.

[0019] Examples of other alcohol components include aliphatic diols such as ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,4-butenediol, 1,3-butanediol, and neopentyl glycol, and trihydric or higher alcohols such as bisphenol A, hydrogenated bisphenol A, sorbitol, pentaerythritol, glycerin, and trimethylolpropane. Among these, ethylene glycol is preferred from the viewpoint of grindability.

[0020] The carboxylic acid component contains an aliphatic dicarboxylic acid compound and an aliphatic monocarboxylic acid compound.

[0021] Examples of the aliphatic dicarboxylic acid compound include succinic acid (carbon number: 4), fumaric acid (carbon number: 4), adipic acid (carbon number: 6), suberic acid (carbon number: 8), azelaic acid (carbon number: 9), sebacic acid (carbon number: 10), dodecanedioic acid (carbon number: 12), tetradecanedioic acid (carbon number: 14), succinic acid derivatives having an alkyl group or an alkenyl group on the side chain, anhydrides of these acids, and alkyl esters of these acids having a carbon number of 1 to 3. Here, when the aliphatic dicarboxylic acid compound is an alkyl ester, the carbon number of the alkyl group is not included in the above carbon number.

[0022] The carbon number of the aliphatic dicarboxylic acid compound is preferably 4 or more and 6 or less, and more preferably 4, from the viewpoint of grindability.

[0023] The aliphatic dicarboxylic acid compound may be either a saturated aliphatic dicarboxylic acid compound or an unsaturated aliphatic dicarboxylic acid compound. In the present invention, however, from the viewpoint of grindability, an unsaturated aliphatic dicarboxylic acid compound is preferred.

[0024] The content of the aliphatic dicarboxylic acid compound in the carboxylic acid component is 3 mol % or more, and preferably 5 mol % or more, from the viewpoint of high molecular weight, and 25 mol % or less, preferably 20 mol % or less, and more preferably 15 mol % or less, from the viewpoint of grindability.

[0025] Examples of the aliphatic monocarboxylic acid compounds include aliphatic monocarboxylic acids such as capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, and behenic acid, and aliphatic monocarboxylic acid compounds such as alkyl esters of these acids in which the alkyl group has 1 to 3 carbon atoms.

[0026] From the viewpoint of grindability, the carbon number of the aliphatic monocarboxylic acid compound is preferably 12 or more, more preferably 14 or more, and from the viewpoint of grindability, preferably 22 or less, more preferably 20 or less, and even more preferably 18 or less. Here, 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.

[0027] The content of the aliphatic monocarboxylic acid compound in the carboxylic acid component is 2 mol % or more, preferably 5 mol % or more, from the viewpoint of grindability, and is 15 mol % or less, preferably 10 mol % or less, from the viewpoint of grindability.

[0028] Examples of carboxylic acid components other than aliphatic dicarboxylic acid compounds and aliphatic monocarboxylic acid compounds include aromatic dicarboxylic acid compounds and trivalent or higher carboxylic acid compounds, and from the viewpoints of abrasion resistance and crushability, aromatic dicarboxylic acid compounds are preferred.

[0029] Examples of the aromatic dicarboxylic acid compound include phthalic acid, isophthalic acid, terephthalic acid, anhydrides of these acids, and alkyl esters of these acids having 1 to 3 carbon atoms.

[0030] The content of the aromatic dicarboxylic acid compound in the carboxylic acid component is preferably 70 mol % or more, more preferably 75 mol % or more, and preferably 95 mol % or less, more preferably 90 mol % or less.

[0031] Examples of trivalent or higher carboxylic acid compounds include 1,2,4-benzenetricarboxylic acid (trimellitic acid), 2,5,7-naphthalenetricarboxylic acid, pyromellitic acid, anhydrides of these acids, and alkyl esters having an alkyl group with 1 to 3 carbon atoms.

[0032] From the viewpoint of abrasion resistance and crushability, the content of trivalent or higher carboxylic acid compounds in the carboxylic acid component is preferably 5 mol % or less, more preferably 3 mol % or less, and even more preferably 0 mol % (i.e., no trivalent or higher carboxylic acid compounds are included).

[0033] Polyethylene terephthalate (PET) may also be used together with the alcohol component and carboxylic acid component. PET, or ethylene glycol and terephthalic acid produced by depolymerization of a portion of it, are used as raw material monomers in a polycondensation reaction and are incorporated into polyester resin. PET is an equimolar polycondensation product of ethylene glycol and terephthalic acid, and the ethylene glycol and terephthalic acid that make up PET are regarded as the alcohol component and carboxylic acid component, respectively.

[0034] The PET may be new PET (virgin PET) or recycled PET. Recycled PET is made by collecting used PET, washing it as necessary, and separating it from other materials before crushing it. The crushed material is then depolymerized to break it down into monomer units, which are then used to resynthesize the material.

[0035] 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, and from the viewpoint 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, and even more preferably 0.70 or less. The IV value is an intrinsic viscosity and is an index of molecular weight.

[0036] In this specification, macromonomers and hydroxycarboxylic acids are not included in the alcohol component and the carboxylic acid component.

[0037] From the viewpoint of adjusting the softening point of the polyester resin, the equivalent ratio of the carboxy group of the carboxylic acid component to the hydroxyl group of the alcohol component (COOH group / OH group) 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.

[0038] In the present invention, the polyester resin may be modified to such an extent that its properties are not substantially impaired. Examples of modified polyester resins include polyester resins grafted or blocked with phenol, urethane, epoxy, or the like by the methods described in JP-A-11-133668, JP-A-10-239903, JP-A-8-20636, etc., and among the modified polyester resins, urethane-modified polyester resins in which polyester resins are urethane-extended with a polyisocyanate compound are preferred.

[0039] The 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 further, if necessary, in the presence of a cocatalyst, a polymerization inhibitor, etc., at a temperature of preferably 160°C or higher, more preferably 200°C or higher, and preferably 250°C or lower, more preferably 240°C or lower.

[0040] 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). 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, based on 100 parts by mass of the total amount of the alcohol component and the carboxylic acid component. Examples of the co-catalyst for the esterification catalyst include gallic acid and its hydrate. 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, based on 100 parts by mass of the total amount 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, per 100 parts by mass of the total amount of the alcohol component and the carboxylic acid component.

[0041] The number average molecular weight of the amorphous polyester resin A is, from the viewpoints of abrasion resistance and high-temperature offset resistance, 3,000 or more, preferably 3,200 or more, and preferably 5,000 or less, more preferably 4,500 or less, and further preferably 4,000 or less.

[0042] The loss tangent (tan δ) of the amorphous polyester resin A at 50°C is 0.20 or less, preferably 0.18 or less, more preferably 0.16 or less, further preferably 0.14 or less, and preferably 0.05 or more, more preferably 0.07 or more, from the viewpoint of grindability. Tan δ is an index of the hardness of the resin, and the larger the value, the softer it is, and the smaller the value, the harder it is. As described above, in the case of an amorphous resin, the viscosity is small below the glass transition temperature (Tg), so the contribution of elasticity is large, and the higher the elasticity, the smaller the tan δ becomes. Tan δ can be adjusted by the content of the aliphatic dicarboxylic acid compound, etc. The higher the molecular weight, the more entanglement between molecular chains increases and the higher the cohesive force, so the high temperature offset resistance increases and the abrasion resistance of the printed matter improves, but on the other hand, the grindability decreases. Therefore, for example, by polycondensing the aliphatic dicarboxylic acid compound in the above-mentioned amount to reduce tan δ, and by introducing an aliphatic monocarboxylic acid compound to partially alleviate the cohesive force between molecular chains, an amorphous polyester resin having good grindability can be obtained even if it has a high molecular weight of about 5,000 in number average molecular weight.

[0043] 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 high-temperature offset resistance, and is preferably 120°C or lower, more preferably 115°C or lower, and even more preferably 110°C or lower from the viewpoint of low-temperature fixability and grindability.

[0044] The crystallinity of a resin is represented by a crystallinity index defined as the ratio of the softening point to the maximum endothermic peak temperature measured by a differential scanning calorimeter, that is, the value of [softening point / maximum endothermic peak temperature]. An amorphous resin is a resin in which no endothermic peak is observed, or if an endothermic peak is observed, the resin has a crystallinity index of more than 1.4, preferably more than 1.5, more preferably 1.6 or more, or less than 0.6, preferably 0.5 or less. On the other hand, the crystalline resin is a resin having a crystallinity index of 0.6 or more, preferably 0.7 or more, more preferably 0.9 or more, and 1.4 or less, preferably 1.2 or less, more preferably 1.1 or less. The crystallinity of the resin can be adjusted by the type and ratio of the raw material monomers, and the 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. In the case of a crystalline resin, the maximum endothermic peak temperature is the melting point.

[0045] The glass transition temperature of the amorphous polyester resin A is preferably 50° C. or higher, more preferably 52° C. or higher, from the viewpoint of storage stability and crushability, and is preferably 65° C. or lower, more preferably 60° C. or lower, from the viewpoint of low-temperature fixability.

[0046] 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 low-temperature fixing property, and is preferably 20 mgKOH / g or less, more preferably 18 mgKOH / g or less, from the viewpoint of charging stability.

[0047] The hydroxyl value of the amorphous polyester resin A is preferably 5 mgKOH / g or more, more preferably 10 mgKOH / g or more, from the viewpoint of low-temperature fixing property, and is preferably 40 mgKOH / g or less, more preferably 30 mgKOH / g or less, from the viewpoint of charging stability.

[0048] The content of 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 even more preferably 100% by mass.

[0049] Examples of other binder resins include amorphous polyester resins other than the amorphous polyester resin A, crystalline polyester resins, vinyl resins such as styrene-acrylic resins, epoxy resins, polycarbonates, polyurethanes, and composite resins containing two or more of these resins.

[0050] Further, the present invention provides a toner for developing electrostatic images, which contains the binder resin for toners of the present invention.

[0051] The content of the binder resin 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 98% by mass or less, and even more preferably 95% by mass or less.

[0052] The toner of the present invention may contain additives such as a colorant, a release agent, a charge control agent, a magnetic powder, a flowability improver, a conductivity adjuster, a reinforcing filler such as a fibrous substance, an antioxidant, and a cleaning property improver, in addition to the binder resin.

[0053] As the colorant, dyes, pigments, magnetic materials, etc. used as colorants for toners can be used. For example, 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. can be mentioned. In the present invention, the toner may be either a black toner or a color toner.

[0054] From the viewpoint of improving the image density and low-temperature fixability of the toner, the content of the colorant is preferably 1 part by mass or more, more preferably 2 parts by mass or more, and preferably 40 parts by mass or less, more preferably 20 parts by mass or less, and even more preferably 10 parts by mass or less, relative to 100 parts by mass of the binder resin.

[0055] Examples of the release agent include hydrocarbon waxes such as polypropylene wax, polyethylene wax, polypropylene-polyethylene copolymer wax, microcrystalline wax, paraffin wax, and Fischer-Tropsch wax, and oxides thereof; ester waxes such as carnauba wax, montan wax, and deacidified waxes thereof, and fatty acid ester wax; fatty acid amides, fatty acids, higher alcohols, and fatty acid metal salts. These may be used alone or in combination of two or more.

[0056] The melting point of the release agent is preferably 60° C. or higher, more preferably 70° C. or higher, from the viewpoint of toner transferability, and is preferably 160° C. or lower, more preferably 140° C. or lower, even more preferably 120° C. or lower, and even more preferably 110° C. or lower, from the viewpoint of low-temperature fixability.

[0057] The content of the release agent is, from the viewpoint of the low-temperature fixing property and offset resistance of the toner and the viewpoint of dispersibility in the binder resin, 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 is preferably 10 parts by mass or less, more preferably 8 parts by mass or less, even more preferably 7 parts by mass or less, relative to 100 parts by mass of the binder resin.

[0058] 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.

[0059] Examples of the positively charged charge control agent include nigrosine dyes such as "Nigrosine Base EX", "Oil Black BS", "Oil Black SO", "Bontron N-01", "Bontron N-04", "Bontron N-07", "Bontron N-09", and "Bontron N-11" (all manufactured by Orient Chemical Industries Co., Ltd.); triphenylmethane dyes containing a tertiary amine as a side chain; quaternary ammonium salt compounds such as "Bontron P-51" (manufactured by Orient Chemical Industries Co., Ltd.), cetyltrimethylammonium bromide, and "COPY CHARGE PX Examples of such resins include "VP435" (manufactured by Clariant), etc.; polyamine resins, such as "AFP-B" (manufactured by Orient Chemical Industry Co., Ltd.); imidazole derivatives, such as "PLZ-2001" and "PLZ-8001" (both manufactured by Shikoku Kasei Corporation); and styrene-acrylic resins, such as "FCA-701PT" and "FCA-201-PS" (manufactured by Fujikura Kasei Co., Ltd.).

[0060] Examples of the negatively chargeable charge control agent include metal-containing azo dyes such as "Varifast Black 3804", "Bontron S-31", "Bontron S-32", "Bontron S-34", and "Bontron S-36" (all manufactured by Orient Chemical Industry Co., Ltd.), "Aizenspiron Black TRH", and "T-77" (manufactured by Hodogaya Chemical Industry Co., Ltd.); metal compounds of benzilic acid compounds such as "LR-147" and "LR-297" (all 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 Industry Co., Ltd.), and "TN-105" (manufactured by Hodogaya Chemical Industry Co., Ltd.); copper phthalocyanine dyes; and quaternary ammonium salts such as "COPY CHARGE NX VP434 (Clariant), nitroimidazole derivatives, and organometallic compounds.

[0061] From the viewpoint of the charging stability of the toner, the content of the charge control agent is preferably 0.01 parts by mass or more, more preferably 0.2 parts by mass or more, and preferably 10 parts by mass or less, more preferably 5 parts by mass or less, even more preferably 3 parts by mass or less, and even more preferably 2 parts by mass or less, relative to 100 parts by mass of the binder resin.

[0062] The toner of the present invention may be a toner obtained by any of the known methods such as a melt kneading method, an emulsion aggregation method, a polymerization method, etc., but from the viewpoint of productivity and dispersibility of the colorant, a pulverized toner by a melt kneading method is preferred. In the case of a pulverized toner by a melt kneading method, for example, raw materials such as a binder resin, a colorant, a release agent, a charge control agent, etc. are uniformly mixed in a mixer such as a Henschel mixer, and then melt kneaded in an internal kneader, a single-screw or twin-screw extruder, an open roll type kneader, etc., and cooled, pulverized, and classified to produce the toner.

[0063] In the toner of the present invention, it is preferable to use an external additive in order to improve transferability. 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 resin fine particles and polytetrafluoroethylene resin fine particles, and two or more of them may be used in combination. Among these, silica is preferable, and from the viewpoint of the transferability of the toner, hydrophobic silica that has been hydrophobized is more preferable.

[0064] Examples of hydrophobic treatment agents for hydrophobizing the surface of silica particles include hexamethyldisilazane (HMDS), dimethyldichlorosilane (DMDS), cyclic silazane, silicone oil, aminosilane, octyltriethoxysilane (OTES), and methyltriethoxysilane.

[0065] From the viewpoint of the chargeability, fluidity, and transferability of the toner, the average particle size of the external additive is preferably 10 nm or more, more preferably 15 nm or more, and is preferably 250 nm or less, more preferably 200 nm or less, and even more preferably 90 nm or less.

[0066] The external addition treatment by mixing the toner particles with the external additives can be carried out according to a conventional method, and a mixer such as a Henschel mixer can be used.

[0067] From the viewpoint of the electrostatic 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 being treated with the external additive, and is preferably 5 parts by mass or less, and more preferably 3 parts by mass or less.

[0068] 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 ) refers to the particle size at which the cumulative volume frequency calculated by volume fraction is 50% calculated 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 regarded as the volume median particle size of the toner.

[0069] The toner of the present invention can be used as it is as a toner for one-component development, 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. EXAMPLES

[0070] The present invention will be described in 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.

[0071] [Number average molecular weight of resin (Mn)] The molecular weight distribution is measured by gel permeation chromatography (GPC) according to the following method, and the number average molecular weight is determined. (1) Preparation of sample solution The sample is dissolved in tetrahydrofuran at 40° C. so that the concentration becomes 0.5 g / 100 mL. Next, this solution is filtered using a PTFE type membrane filter "DISMIC-25JP" (manufactured by Toyo Roshi Kaisha, Ltd.) with a pore size of 0.20 μm to remove undissolved components, and the sample solution is obtained. (2) Molecular weight measurement The following measuring device and analytical column are used, tetrahydrofuran is used as the eluent at a flow rate of 1 mL per minute, and the column is stabilized in a thermostatic bath at 40°C. 100 μL of the sample solution is injected into the column for measurement. The molecular weight of the sample is calculated based on a calibration curve that has been prepared in advance. The calibration curve used here is a series of monodisperse polystyrenes (A-500 (5.0×10 2 ), A-1000(1.01×10 3 ), A-2500(2.63×10 3 ), A-5000(5.97×10 3 ), F-1(1.02×10 4 ), F-2(1.81×10 4 ), F-4(3.97×10 4 ), F-10(9.64×10 4 ), F-20(1.90×10 5 ), F-40(4.27×10 5 ), F-80(7.06×10 5 ), F-128(1.09×10 6 )) was used as a standard sample. The numbers in parentheses indicate the molecular weight. Measuring device: HLC-8220GPC (Tosoh Corporation) Analytical column: TSKgel GMH XL +TSKgel G3000H XL (Manufactured by Tosoh Corporation)

[0072] [Resin loss tangent (tan δ)] A 2.0 g sample is pressed into a cylindrical tablet with a diameter of 2.5 cm and a thickness of 2 to 3 mm using a press, and the tablet is measured using a modular compact rheometer "MCR302" (manufactured by Anton Paar Japan Ltd.) under the measurement conditions for intervals 1 and 2 below, and the loss tangent (tan δ) at 50°C during interval 2 is measured. Interval 1 Number of points: 156 points, point interval: 10 seconds (constant), strain: 0.01% (constant), frequency: 1Hz (constant), temperature: 40℃ (constant) Interval 2 Number of points: 300 points, point interval: 0.2 min (constant), strain: 0.01 to 1% (logarithmic slope), frequency: 1 Hz (constant), temperature: 40°C to 195°C (linear slope), rate (heating rate): 5°C / min, normal force (FN): 0N

[0073] [Softening point of resin] Using a flow tester "CFT-500D" (Shimadzu Corporation), 1g of sample is heated at a temperature increase rate of 6℃ / min while applying a load of 1.96MPa with the plunger, and extruding the sample from a nozzle with a diameter of 1mm and a length of 1mm. The amount of plunger descent of the flow tester is plotted against the temperature, and the temperature at which half of the sample has flowed out is taken as the softening point.

[0074] [Maximum endothermic peak temperature of resin] Using a differential scanning calorimeter "Q-100" (manufactured by TA Instruments Japan, Inc.), weigh 0.01 to 0.02 g of sample into an aluminum pan, cool from room temperature (25°C) to 0°C at a rate of 10°C / min, and maintain at 0°C for 1 minute. Then, measure at a rate of 10°C / min. The temperature of the peak with the largest peak area among the observed endothermic peaks is regarded as the maximum endothermic peak temperature.

[0075] [Glass transition temperature of resin] Using a differential scanning calorimeter "Q-100" (manufactured by TA Instruments Japan), 0.01 to 0.02 g of sample is weighed into an aluminum pan, heated from room temperature (25°C) to 200°C at a heating rate of 10°C / min, and cooled from that temperature to 0°C at a heating 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 glass transition temperature is 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 top of the peak.

[0076] [Acid value and hydroxyl value of resin] Measure based on the method of JIS K 0070:1992, except that the measurement solvent is changed from the ethanol and ether mixture specified in JIS K 0070:1992 to a mixture of acetone and toluene (acetone:toluene = 1:1 (volume ratio)).

[0077] [PET IV value] The viscosity can be determined by dissolving the material in a mixed solvent of phenol / tetrachloroethane at a concentration of 60 / 40 (mass ratio) at 4 g / L, measuring with an Ubbelohde viscometer, and calculating according to 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 alone to fall, t1: number of seconds for the sample solution to fall).)

[0078] [Melting point of release agent] Using a differential scanning calorimeter "Q-100" (manufactured by TA Instruments Japan Co., Ltd.), 0.02 g of 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. The sample is then heated at a rate of 10°C / min, the amount of heat is measured, and the maximum endothermic peak temperature is taken as the melting point.

[0079] [Average particle size of external additives] The average particle size refers to the number-average particle size, and is calculated by measuring the particle sizes (average of major and minor diameters) of 500 particles in a scanning electron microscope (SEM) photograph and averaging these by number.

[0080] [Volume median particle size of toner (D 50 )〕 Measuring instrument: "Coulter Multisizer (registered trademark) III" (manufactured by Beckman Coulter, Inc.) Aperture diameter: 50μm Analysis software: "Multisizer (registered trademark) III version 3.51" (Beckman Coulter, Inc.) Electrolyte: "Isoton (registered trademark) II" (manufactured by Beckman Coulter, Inc.) Dispersion liquid: Polyoxyethylene lauryl ether "Emulgen (registered trademark) 109P" (manufactured by Kao Corporation, HLB (Griffin) = 13.6) was dissolved in the electrolyte to adjust the concentration to 5% by mass. Dispersion conditions: 10 mg of the measurement sample is added to 5 mL of the dispersion liquid, and dispersed for 1 minute using an ultrasonic disperser (machine name: US-1, manufactured by SND Co., Ltd., output: 80 W). Then, 25 mL of electrolyte is added, and the mixture is further dispersed for 1 minute using the ultrasonic disperser to prepare a sample dispersion liquid. Measurement conditions: The sample dispersion was added to 100 mL of the electrolyte to adjust the concentration so that the particle size of 30,000 particles could be measured in 20 seconds. Then, 30,000 particles were measured, and the volume median particle size (D 50 ) is required.

[0081] Examples A1 and A7 The alcohol component, carboxylic acid component other than fumaric acid, esterification catalyst, and cocatalyst shown in Tables 1 and 2 were placed in a 10-liter four-neck flask equipped with a thermometer, a stainless steel stirring rod, a fractionation column, a dehydration tube, a cooling tube, and a nitrogen inlet tube, and the temperature was raised to 235°C in a mantle heater in a nitrogen atmosphere, and the reaction was carried out at normal pressure for 6 hours, and then at reduced pressure of 8 kPa for 1 hour. After that, the mixture was cooled to 180°C at normal pressure, and fumaric acid and a radical polymerization inhibitor were added, and the temperature was raised to 220°C at a rate of 10°C / h. The reaction was further carried out at 220°C and 8 kPa until the desired softening point, and an amorphous polyester resin was obtained. Various physical properties are shown in Tables 1 and 2.

[0082] Examples A2 and A5 The alcohol component, carboxylic acid component other than fumaric acid, PET, esterification catalyst, and cocatalyst shown in Table 1 were placed in a 10-liter four-neck flask equipped with a thermometer, a stainless steel stirring rod, a fractionation column, a dehydration tube, a cooling tube, and a nitrogen inlet tube, and the temperature was raised to 235°C in a mantle heater in a nitrogen atmosphere, and the reaction was carried out at normal pressure for 4 hours, then cooled to 200°C and reacted at reduced pressure of 20kPa for 1.0 hour. After that, the mixture was cooled to 180°C at normal pressure, and fumaric acid and a radical polymerization inhibitor were added, and the temperature was raised to 210°C at a rate of 10°C / h. Furthermore, the reaction was carried out at 210°C and 8kPa until the desired softening point, and an amorphous polyester resin was obtained. Various physical properties are shown in Table 1.

[0083] Example A3 The alcohol component, carboxylic acid component other than fumaric acid, esterification catalyst, and cocatalyst shown in Table 1 were placed in a 10-liter four-neck flask equipped with a thermometer, a stainless steel stirring rod, a fractionation column, a dehydration tube, a cooling tube, and a nitrogen inlet tube, and the temperature was raised to 235°C in a mantle heater in a nitrogen atmosphere, and the reaction was carried out at normal pressure for 3 hours, and then at reduced pressure of 8 kPa for 1 hour. After that, the mixture was cooled to 180°C at normal pressure, and fumaric acid and a radical polymerization inhibitor were added, and the temperature was raised to 220°C at a rate of 10°C / h. Furthermore, the reaction was carried out at 220°C and 8 kPa until the desired softening point, and an amorphous polyester resin was obtained. Various physical properties are shown in Table 1.

[0084] Examples A4 and A6 The alcohol component, carboxylic acid component other than fumaric acid, PET, esterification catalyst, and cocatalyst shown in Tables 1 and 2 were placed in a 10-liter four-neck flask equipped with a thermometer, a stainless steel stirring rod, a fractionation column, a dehydration tube, a cooling tube, and a nitrogen inlet tube, and the temperature was raised to 235°C in a mantle heater in a nitrogen atmosphere, and the reaction was carried out at normal pressure for 5.5 hours, then cooled to 200°C, and the reaction was carried out at reduced pressure of 20kPa for 1 hour. After that, the reaction was cooled to 180°C at normal pressure, and fumaric acid and a radical polymerization inhibitor were added, and the temperature was raised to 220°C at a rate of 10°C / h. Furthermore, the reaction was carried out at 220°C and 8kPa until the desired softening point, and an amorphous polyester resin was obtained. Various physical properties are shown in Tables 1 and 2.

[0085] Example A8 An amorphous polyester resin was obtained in the same manner as in Example A1, except that adipic acid was used instead of fumaric acid and no radical polymerization inhibitor was used. Various physical properties are shown in Table 2.

[0086] Example A9 An amorphous polyester resin was obtained in the same manner as in Example A5, except that succinic acid was used instead of fumaric acid and no radical polymerization inhibitor was used. Various physical properties are shown in Table 2.

[0087] Comparative Example A1 The alcohol component, terephthalic acid, esterification catalyst, and cocatalyst shown in Table 3 were placed in a 10-liter four-neck flask equipped with a thermometer, a stainless steel stirring rod, a fractionation column, a dehydration tube, a cooling tube, and a nitrogen inlet tube, and the temperature was raised to 235°C in a mantle heater in a nitrogen atmosphere, and the reaction was carried out at normal pressure for 5 hours, and then at reduced pressure of 8 kPa for 1 hour. After that, the mixture was cooled to 180°C at normal pressure, and adipic acid was added, and the temperature was raised to 220°C at a rate of 10°C / h. The reaction was further carried out at 220°C and 8 kPa until the desired softening point, and an amorphous polyester resin was obtained. Various physical properties are shown in Table 3.

[0088] Comparative example A2 The alcohol component, terephthalic acid, esterification catalyst, and cocatalyst shown in Table 3 were placed in a 10-liter four-neck flask equipped with a thermometer, a stainless steel stirring rod, a fractionation column, a dehydration tube, a cooling tube, and a nitrogen inlet tube, and the temperature was raised to 235°C in a mantle heater in a nitrogen atmosphere, and the reaction was carried out at normal pressure for 3 hours, and then at reduced pressure of 8 kPa for 1 hour. After that, the mixture was cooled to 180°C at normal pressure, and fumaric acid and a radical polymerization inhibitor were added, and the temperature was raised to 210°C at a rate of 10°C / h. Furthermore, the reaction was carried out at 210°C and 8 kPa until the desired softening point, and an amorphous polyester resin was obtained. Various physical properties are shown in Table 3.

[0089] Comparative example A3 The alcohol component, terephthalic acid, PET, esterification catalyst, and cocatalyst shown in Table 3 were placed in a 10-liter four-neck flask equipped with a thermometer, a stainless steel stirring rod, a fractionation column, a dehydration tube, a cooling tube, and a nitrogen inlet tube, and the temperature was raised to 235°C in a mantle heater in a nitrogen atmosphere, and the reaction was carried out at normal pressure for 4.0 hours, then cooled to 200°C, and the reaction was carried out at reduced pressure of 20kPa for 1 hour. After that, the reaction was cooled to 180°C at normal pressure, and fumaric acid and a radical polymerization inhibitor were added, and the temperature was raised to 210°C at a rate of 10°C / h. Furthermore, the reaction was carried out at 210°C and 8kPa until the desired softening point, and an amorphous polyester resin was obtained. Various physical properties are shown in Table 3.

[0090] Comparative example A4 The alcohol component, carboxylic acid component, esterification catalyst, and cocatalyst shown in Table 3 were placed in a 10-liter four-neck flask equipped with a thermometer, a stainless steel stirring rod, a fractionation column, a dehydration tube, a cooling tube, and a nitrogen inlet tube, and the temperature was raised to 235°C in a mantle heater in a nitrogen atmosphere, and the reaction was carried out at normal pressure for 5 hours, and then at 8 kPa until the desired softening point was reached, yielding an amorphous polyester resin. Various physical properties are shown in Table 3.

[0091] Comparative Example A5 The alcohol component, carboxylic acid component other than fumaric acid, PET, esterification catalyst, and cocatalyst shown in Table 3 were placed in a 10-liter four-neck flask equipped with a thermometer, a stainless steel stirring rod, a fractionation column, a dehydration tube, a cooling tube, and a nitrogen inlet tube, and the temperature was raised to 235°C in a mantle heater in a nitrogen atmosphere, and the reaction was carried out at normal pressure for 1 hour, then cooled to 200°C and reacted at reduced pressure of 20kPa for 1.0 hour. After that, the mixture was cooled to 180°C at normal pressure, and fumaric acid and a radical polymerization inhibitor were added, and the temperature was raised to 210°C at a rate of 10°C / h. Furthermore, the reaction was carried out at 210°C and 8kPa until the desired softening point, and an amorphous polyester resin was obtained. Various physical properties are shown in Table 3.

[0092] Comparative example A6 The alcohol component, carboxylic acid component other than fumaric acid, esterification catalyst, and cocatalyst shown in Table 3 were placed in a 10-liter four-neck flask equipped with a thermometer, a stainless steel stirring rod, a fractionation column, a dehydration tube, a cooling tube, and a nitrogen inlet tube, and the temperature was raised to 235°C in a mantle heater in a nitrogen atmosphere, and the reaction was carried out at normal pressure for 7.5 hours, and then at reduced pressure of 8 kPa for 1 hour. After that, the mixture was cooled to 180°C at normal pressure, and fumaric acid and a radical polymerization inhibitor were added, and the temperature was raised to 220°C at a rate of 10°C / h. Then, the reaction was carried out at 220°C and 8 kPa until the desired softening point, and an amorphous polyester resin was obtained. Various physical properties are shown in Table 3.

[0093] [Table 1]

[0094] [Table 2]

[0095] [Table 3]

[0096] Test Example 1 [Resin Grindability] A roughly pulverized amorphous polyester resin was prepared in a volume of about 1000 mL. Using a sieve shaker (Verder Scientific), the sample was sieved through 16 mesh and 22 mesh, and 20 g of the sample remaining between the 16 mesh and 22 mesh was precisely weighed. Next, the precisely weighed 20 g sample was pulverized for 10 seconds using a benchtop grinder (LAB MILL OML-1: Osaka Chemical Co., Ltd.), and further sieved through 30 mesh until the sample no longer fell off, and the sample remaining on the 30 mesh was precisely weighed. The grindability index was calculated from the following formula, and the average value of three measurements was calculated. The results are shown in Table 4. The higher the grindability index, the better the resin grindability, and the more the productivity of the toner can be improved. The grindability index is preferably 92.0% or more, and more preferably 95.0% or more. Grindability index (%) = [[20(g) - mass (g) of sample remaining on 30 mesh] / 20(g)] × 100

[0097] Examples B1 to B9 and Comparative Examples B1 to B6 100 parts by mass of the binder resin shown in Table 4, 4 parts by mass of the colorant "MOGUL (registered trademark)-L" (manufactured by Cabot Corporation, carbon black), 1 part by mass of the charge control agent "T-77" (manufactured by Hodogaya Chemical Industry Co., Ltd.), and 3 parts by mass of the release agent "Carnauba Wax C1" (manufactured by Kato Yoko Co., Ltd., melting point: 83 ° C.) as a release agent were thoroughly stirred with a Henschel mixer, and then melt-kneaded using a co-rotating twin-screw extruder with a total length of 1560 mm, a screw diameter of 42 mm, and a barrel inner diameter of 43 mm. The screw rotation speed was 200 r / min, the heating setting temperature in the screw was 90 ° C., the temperature of the kneaded product was 140 ° C., the supply rate of the kneaded product was 10 kg / h, and the average residence time was about 18 seconds. The obtained kneaded product was cooled from 140 ° C. to 50 ° C. in 1.5 hours, rolled and cooled with a cooling roller set at 50 ° C., and then left to stand at 45 ° C. for 4 hours. After that, it is coarsely crushed, then finely crushed in a jet mill, classified, and the volume median particle size (D 50 ) Toner particles of 5.5 μm were obtained.

[0098] To 100 parts by mass of the obtained toner particles, 1.2 parts by mass of external additive "R972" (manufactured by Nippon Aerosil Co., Ltd., hydrophobic silica, hydrophobic treatment agent: DMDS, average particle size: 16 nm) and 1.4 parts by mass of external additive "RY50" (manufactured by Nippon Aerosil Co., Ltd., hydrophobic silica, hydrophobic treatment agent: silicone oil, average particle size: 40 nm) were added, and the mixture was mixed in a Henschel mixer at 3,600 r / min for 5 minutes to perform external additive treatment and obtain a toner.

[0099] Test Example 2 [Toner Abrasion Resistance] A4 size coated paper "OK ​​Topcoat+" (Oji Paper Co., Ltd., basis weight: 104.7 g / m 2Using a commercially available printer "OKI-712" (manufactured by OKI Data Corporation), each toner shown in Table 4 was printed on a plain paper (paper thickness: approximately 82 μm) leaving a margin of 1 cm from the top edge of the paper, leaving a solid image of 15.8 cm length and 2 cm width (print density: black and white 25%) without fixing, in plain paper mode. Next, a thermostatic chamber set to 125°C was used to melt and dry for 5 minutes to fix the solid image, resulting in a printout with an image density (OD) of 0.20±0.01. The obtained print was subjected to a Gakushin RT300 abrasion fastness tester (Fukuda Kikai Kogyo Co., Ltd.) with two layers of cloth (BEMCOT, Asahi Kasei Corporation) attached to the abrader, and rubbed with a load of 2N back and forth multiple times, and the number of times the density of the image on the cloth after rubbing reached 0.20 was counted. The image density was measured using a SpectroEye colorimeter (GretagMacbeth Co., Ltd.) and the cloth before rubbing was set as 0, and the average value of three points was calculated. The results are shown in Table 4. The more the number of rubs, the less the image is transferred to the cloth and the better the abrasion resistance.

[0100] [Table 4]

[0101] From the above results, it is found that the binder resins of the examples have excellent grindability, even though they have a high molecular weight (Mn≧3,000), and the toners containing these binder resins also have excellent abrasion resistance. In contrast, the results of the comparative examples show that grindability and abrasion resistance are greatly affected by the molecular weight, and that when the molecular weight is small, the abrasion resistance is poor regardless of the amount of the aliphatic dicarboxylic acid compound and the aliphatic monocarboxylic acid compound and the adjustment of tan δ, and when the molecular weight is large, the abrasion resistance is excellent but the grindability is low. Therefore, it is clear that the effect of adjusting these is specific to amorphous polyester resins with high molecular weights (Mn≧3,000). [Industrial Applicability]

[0102] The toner for developing electrostatic images containing the binder resin composition for toners of the present invention is suitably used for developing latent images formed in electrostatic image developing methods, electrostatic recording methods, electrostatic printing methods and the like.

Claims

1. A binder resin composition for toner containing an amorphous polyester resin A which is a polycondensate of an alcohol component and a carboxylic acid component, wherein the number average molecular weight of the amorphous polyester resin A is 3,000 or more, the loss tangent at 50°C is 0.20 or less, and the carboxylic acid component contains 3 mol% to 25 mol% of an aliphatic dicarboxylic acid compound and 2 mol% to 15 mol% of an aliphatic monocarboxylic acid compound.

2. The toner binder resin composition according to claim 1, wherein the aliphatic monocarboxylic acid compound has 12 or more carbon atoms and 22 or less carbon atoms.

3. The toner binder resin composition according to claim 1, wherein the aliphatic dicarboxylic acid compound has 4 to 6 carbon atoms.

4. The binder resin composition for toner according to claim 1, wherein the aliphatic dicarboxylic acid compound is an unsaturated aliphatic dicarboxylic acid compound.

5. A toner for developing electrostatic images, comprising the toner binder resin composition according to any one of claims 1 to 4.