Binder resin composition for toner

Abstract

To provide a binder resin composition for a toner which is excellent in durability, a method for producing the same, 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 a crystalline polyester resin and an amorphous polyester resin, wherein the crystalline polyester resin contains a crystalline block copolymer (C) in which a crystalline polyester segment (c1) which is a polycondensation product of an alcohol component containing aliphatic diol and a carboxylic acid component containing an aliphatic dicarboxylic acid compound, and a crystalline polyester segment (c2) obtained by ring-opening polymerization of cyclic lactone are bonded to each other through an ester bond, and the amorphous polyester resin contains an amorphous polyester resin (A) having a softening point of 80°C or more and 120°C or less, a method for producing the same, 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, for example, an electrophotographic method, an electrostatic recording method, an electrostatic printing method, etc., a method for producing the same, and a toner for developing an electrostatic image containing the binder resin composition. [Background technology]

[0002] Patent Document 1 discloses a toner resin characterized in that a crystalline polyester unit (CU) is chemically bonded to an amorphous polymer unit (AU) having an ester bond density of 6 to 18 mmol / g.

[0003] Patent Document 2 discloses a method for producing a dispersion (Q) of organic fine particles (A) dispersed in carbon dioxide (X) in a liquid or supercritical state, by dispersing a solution (L) of a resin (B) in a solvent (S), a colorant dispersion (C), and, if necessary, a wax dispersion (D), to form resin particles (Z1) containing the resin (B), the colorant (k), the solvent (S), and, if necessary, the wax (w) to the surface of which the organic fine particles (A) are fixed, and then treating the resin particles (Z1) with the resin particles (Y1), which contain the resin (B), the colorant (k), the solvent (S), and, if necessary, the wax (w). The method also includes the steps of removing the resin particles (Z1) from the dispersion (Q) in which the obtained resin particles (Y1) are dispersed in a dispersion medium containing the resin particles (B), the colorant (k), the solvent (S), and the wax (w). The present invention discloses a method for producing resin particles (Z), in which resin (B) is a resin composed of a crystalline portion (a) and a non-crystalline portion (b) having lactone ring-opening polymer (p) as an essential component, and colorant dispersion (C) is a dispersion in which colorant (k), having a median diameter of 1 μm or less, is dispersed in (S), the dispersion being obtained by mixing colorant (k), dispersant (l) having an acid value and amine value total (mgKOH / g) of 20 to 250, solvent (S), and carbon dioxide (X) in a liquid or supercritical state at a pressure of 2 MPa or more, and then expanding the mixture under reduced pressure to vaporize and remove (X). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-185451 [Patent Document 2] Japanese Patent Application Laid-Open No. 2011-94137 Summary of the Invention [Problem to be solved by the invention]

[0005] In order to improve low-temperature fixability as a binder resin for toner, the use of an amorphous polyester resin in combination with a crystalline polyester resin has been investigated.

[0006] However, although the crystalline polyester resin improves low-temperature fixability, since the crystalline polyester resin, which is generally a polycondensation product of aliphatic monomers, is highly hydrophobic, it is difficult to disperse in the amorphous polyester resin, and domains of the crystalline polyester resin are exposed on the toner surface, which results in a deterioration in the durability of the toner.

[0007] The present invention relates to a binder resin composition for toners having excellent durability, a method for producing the same, and a toner for developing electrostatic images containing the binder resin composition. [Means for solving the problem]

[0008] The present invention provides [1] A binder resin composition for toners, comprising a crystalline polyester resin and an amorphous polyester resin, wherein the crystalline polyester resin comprises a crystalline block polymer (C) in which a crystalline polyester segment (c1), which is a polycondensate of an alcohol component containing an aliphatic diol and a carboxylic acid component containing an aliphatic dicarboxylic acid compound, and a crystalline polyester segment (c2), which is obtained by ring-opening polymerization of a cyclic lactone, are bonded via an ester bond, and the amorphous polyester resin comprises an amorphous polyester resin (A) having a softening point of 80°C or higher and 120°C or lower. [2] A method for producing a binder resin composition for toner according to [1] above, which comprises mixing a crystalline polyester resin and an amorphous polyester resin, wherein the crystalline polyester resin contains a crystalline block polymer (C) obtained by ring-opening polymerization of a cyclic lactone at 80°C or higher and 120°C or lower with a crystalline polyester segment (c1), which is a polycondensate of an alcohol component containing an aliphatic diol and a carboxylic acid component containing an aliphatic dicarboxylic acid compound; and [3] A toner for developing electrostatic images, comprising the binder resin composition for toners according to [1] above. Regarding. [Effects of the Invention]

[0009] The binder resin composition for toner of the present invention exhibits excellent effects in terms of durability. DETAILED DESCRIPTION OF THE INVENTION

[0010] The binder resin composition for toner of the present invention contains a crystalline block polymer (C) in which a crystalline polyester segment (c1) using an aliphatic monomer and a crystalline polyester segment (c2) obtained by ring-opening polymerization of a cyclic lactone are bonded via an ester bond, and an amorphous polyester resin having a specific softening point. The reason why the effects of the present invention are achieved is not clear in detail, but is presumed to be as follows.

[0011] Because ring-opening polymers of cyclic lactones such as poly-ε-caprolactone have high compatibility with amorphous polyester resins, crystalline polyester resins containing polycyclic lactone segments disperse well in toners. Such crystalline polyester resins have a high affinity for amorphous polyester resins, and the polycyclic lactone segments form interfaces with the amorphous polyester resin, forming domains derived from the crystalline polyester segment (c1). In particular, when the crystalline polyester resin contains an amorphous polyester resin with a low softening point, the viscosity of the matrix (amorphous polyester resin) is low during the crystallization process of the crystalline polyester resin during cooling after toner processing, improving the mobility of the crystalline polyester resin. This allows the dispersing groups of the polycyclic lactone to be appropriately distributed at the interface, resulting in fine dispersion of the domains derived from the crystalline polyester segment (c1). The toner binder resin composition of the present invention has small crystalline polyester resin domains, reducing the exposed area of ​​the crystalline polyester resin on the toner surface, thereby improving durability. Furthermore, when a toner containing a crystalline polyester resin is stored for a long period of time, crystallization progresses, the crystalline polyester domains become coarse, and the durability of the toner decreases. However, in the present invention, the polycyclic lactone segment contained in the crystalline polyester resin, which has high affinity with the amorphous polyester resin, acts as a dispersing group, so that the dispersion diameter of the crystalline polyester resin does not increase even after long-term storage, and high durability can be maintained.

[0012] In the present invention, the crystalline polyester resin contains a crystalline block polymer (C) in which a crystalline polyester segment (c1), which is a polycondensate of an alcohol component containing an aliphatic diol and a carboxylic acid component containing an aliphatic dicarboxylic acid compound, and a crystalline polyester segment (c2), which is formed by ring-opening polymerization of a cyclic lactone, are bonded via an ester bond.

[0013] The crystalline polyester segment (c1) is formed by polycondensation of an alcohol component containing an aliphatic diol and a carboxylic acid component containing an aliphatic dicarboxylic acid compound.

[0014] Examples of the aliphatic diol include ethylene glycol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, and 1,12-dodecanediol.

[0015] The number of carbon atoms in the aliphatic diol is preferably 2 or more, more preferably 4 or more, and preferably 12 or less, more preferably 10 or less, from the viewpoint of improving the low-temperature fixability of the toner.

[0016] Furthermore, from the viewpoint of improving the low-temperature fixability of the toner, the aliphatic diol preferably has a hydroxyl group at the end of the carbon chain, and is more preferably an α,ω-straight-chain alkanediol.

[0017] The alcohol component may contain alcohols other than aliphatic diols, but the content of the aliphatic diols in the alcohol component is preferably 70 mol% or more, more preferably 90 mol% or more, and even more preferably 95 mol% or more, and 100 mol% or less.

[0018] Examples of other alcohol components include aromatic diols such as alkylene oxide adducts of bisphenol A, and trihydric or higher alcohols such as glycerin.

[0019] Examples of aliphatic dicarboxylic acid compounds include succinic acid (number of carbon atoms: 4), suberic acid (number of carbon atoms: 8), azelaic acid (number of carbon atoms: 9), sebacic acid (number of carbon atoms: 10), dodecanoic diacid (number of carbon atoms: 12), tetradecanoic diacid (number of carbon atoms: 14), anhydrides of these acids, and alkyl esters of these acids having 1 to 3 carbon atoms. In the present invention, the carboxylic acid compounds include not only free acids but also anhydrides that decompose during the reaction to produce acids, and alkyl esters having 1 to 3 carbon atoms.

[0020] The chain hydrocarbon group in the aliphatic dicarboxylic acid compound may be linear or branched, and the number of carbon atoms in the aliphatic dicarboxylic acid compound is preferably 4 or more, more preferably 6 or more, and even more preferably 10 or more, from the viewpoint of improving the low-temperature fixability of the toner, and is preferably 14 or less, and more preferably 13 or less. However, the number of carbon atoms in the alkyl group of the alkyl ester moiety is not included in the number of carbon atoms in the aliphatic dicarboxylic acid compound.

[0021] The carboxylic acid component may contain a carboxylic acid compound other than an aliphatic dicarboxylic acid compound, but the content of the aliphatic dicarboxylic acid compound in the carboxylic acid component is preferably 80 mol % or more, more preferably 90 mol % or more, and even more preferably 95 mol % or more, and 100 mol % or less.

[0022] Examples of other carboxylic acid components include aromatic dicarboxylic acid compounds such as terephthalic acid and isophthalic acid, and trivalent or higher carboxylic acid compounds such as trimellitic acid and pyromellitic acid.

[0023] The alcohol component may contain a monohydric alcohol, and the carboxylic acid component may contain a monocarboxylic acid compound, as appropriate.

[0024] In this specification, macromonomers and hydroxycarboxylic acids are not included in the alcohol component and carboxylic acid component.

[0025] The equivalent ratio of the carboxyl groups of the carboxylic acid component to the hydroxyl groups of the alcohol component (COOH groups / OH groups) is preferably 0.7 or more, more preferably 0.8 or more, from the viewpoint of charging stability, and is preferably 1.3 or less, more preferably 1.2 or less, from the viewpoint of low-temperature fixability.

[0026] The crystalline polyester segment (c1) can be formed, for example, by polycondensing the raw material monomers, 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, a polymerization inhibitor, etc., at a temperature of preferably 120°C or higher, more preferably 180°C or higher, and preferably 230°C or lower, more preferably 220°C or lower.

[0027] Examples of esterification catalysts include tin compounds such as dibutyltin oxide and tin(II) 2-ethylhexanoate, and titanium compounds such as titanium diisopropoxybis(triethanolaminate), with tin compounds being preferred. The amount of the esterification catalyst used is preferably 0.01 parts by mass or more, more preferably 0.1 parts by mass or more, and preferably 1.5 parts by mass or less, more preferably 1 part by mass or less, per 100 parts by mass of the raw material monomer. Examples of co-catalysts for the esterification catalyst include gallic acid. The amount of the co-catalyst used is preferably 0.001 parts by mass or more, more preferably 0.01 parts by mass or more, and preferably 0.5 parts by mass or less, more preferably 0.1 parts by mass or less, per 100 parts by mass of the raw material monomer. Examples of radical polymerization inhibitors include tert-butylcatechol. The amount of the radical 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, more preferably 0.1 parts by mass or less, per 100 parts by mass of the raw material monomer.

[0028] From the viewpoint of durability, the SP value of the crystalline polyester segment (c1) is preferably 9.2 (cal / cm 3 ) 1 / 2 More preferably, 9.4 (cal / cm 3 ) 1 / 2 More preferably, 9.7 (cal / cm 3 ) 1 / 2 From the viewpoint of low temperature fixability, it is preferably 11.0 (cal / cm 3 ) 1 / 2 Less than or equal to 10.5 (cal / cm 3 ) 1 / 2or less, more preferably 10.1 (cal / cm 3 ) 1 / 2 The following is the result.

[0029] In the present invention, the SP value means the solubility parameter according to the Fedors method, which is a value δ calculated based on the following formula described in [Robert F. Fedors, Polymer Engineering and Science, 14, 147-154 (1974)]. Fedors' formula: δ = (ΣΔei / ΣΔvi) 1 / 2 [Unit: (cal / cm 3 ) 1 / 2 〕 [Where, Δei: evaporation energy of atoms and atomic groups (cal / mol), Δvi: molar volume (cm 3 / mol).

[0030] The crystalline polyester segment (c2) is formed by ring-opening polymerization of a cyclic lactone.

[0031] Examples of cyclic lactones include ε-caprolactone, β-propiolactone, γ-butyrolactone, and δ-valerolactone. Of these, ε-caprolactone is preferred from the viewpoint of durability.

[0032] The crystalline block polymer (C) can be obtained, for example, by mixing a crystalline polyester segment (c1) with a cyclic lactone and then subjecting the crystalline polyester segment (c1) to ring-opening polymerization with the cyclic lactone.

[0033] The temperature for the ring-opening polymerization of the cyclic lactone is preferably 80°C or higher, more preferably 85°C or higher, and even more preferably 90°C or higher, and preferably 120°C or lower, more preferably 110°C or lower, and even more preferably 100°C or lower. By carrying out the ring-opening polymerization of the cyclic lactone at a relatively low temperature, transesterification is less likely to occur, and a block polymer with a simple structure in which linear segments are linked can be obtained. Therefore, the length of each segment can be easily controlled by adjusting the charging ratio of the raw material monomers for the crystalline polyester segment (c1) and the cyclic lactone.

[0034] In the crystalline block polymer (C), the mass ratio of the crystalline polyester segment (c1) to the crystalline polyester segment (c2) (crystalline polyester segment (c1) / crystalline polyester segment (c2)) is preferably 10 / 90 or more, more preferably 20 / 80 or more, and even more preferably 30 / 70 or more from the viewpoint of heat-resistant storage stability, and is preferably 90 / 10 or less, more preferably 80 / 20 or less, and even more preferably 70 / 30 or less from the viewpoint of durability.

[0035] The softening point of the crystalline block polymer (C) is preferably 40°C or higher, more preferably 45°C or higher, and even more preferably 50°C or higher from the viewpoint of heat-resistant storage stability, and is preferably 100°C or lower, more preferably 90°C or lower from the viewpoint of low-temperature fixability.

[0036] The crystallinity of a resin is expressed 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]. The crystalline resin has a crystallinity index of 0.6 or more, preferably 0.7 or more, more preferably 0.9 or more, and 1.4 or less, preferably 1.2 or less, more preferably 1.1 or less. On the other hand, an amorphous resin is a resin in which no endothermic peak is observed, or if an endothermic peak is observed, the resin has a crystallinity index of more than 1.4, preferably more than 1.5, more preferably 1.6 or more, or less than 0.6, preferably 0.5 or less. The crystallinity of the resin can be adjusted by the types and ratios of raw material monomers, and production conditions (e.g., reaction temperature, reaction time, cooling rate), etc. The maximum endothermic peak temperature refers to the temperature of the peak with the largest peak area among the observed endothermic peaks. In the crystalline resin segment, the maximum endothermic peak temperature is taken as the melting point. As described below, the crystalline block polymer (C) in the present invention has endothermic peaks corresponding to the melting points of the crystalline polyester segment (c1) and the crystalline polyester segment (c2). In this case, the melting point of the endothermic peak with the larger peak area is used to calculate the crystallinity index.

[0037] The melting point of the crystalline block polymer (C) is preferably 40° C. or higher, more preferably 50° C. or higher, and even more preferably 60° C. or higher from the viewpoint of durability, and is preferably 100° C. or lower, more preferably 90° C. or lower from the viewpoint of low-temperature fixability. The crystalline block polymer (C) has melting points attributable to the crystalline polyester segment (c1) and the crystalline polyester segment (c2), and it is preferred that each melting point be within the above-mentioned range.

[0038] From the viewpoint of charge stability, the acid value of the crystalline block polymer (C) is preferably 5 mgKOH / g or more, more preferably 10 mgKOH / g or more, and preferably 40 mgKOH / g or less, more preferably 30 mgKOH / g or less, and even more preferably 25 mgKOH / g or less.

[0039] From the viewpoint of charging stability, the hydroxyl value of the crystalline block polymer (C) is preferably 5 mgKOH / g or more, more preferably 10 mgKOH / g or more, and is preferably 40 mgKOH / g or less, more preferably 25 mgKOH / g or less.

[0040] The content of the crystalline block polymer (C) in the crystalline polyester resin is preferably 80% by mass or more, more preferably 90% by mass or more, and even more preferably 95% by mass or more, but 100% by mass or less.

[0041] The content of the crystalline block polymer (C) in the binder resin composition for toner is preferably 2% by mass or more, and preferably 30% by mass or less, more preferably 25% by mass or less, and even more preferably 15% by mass or less.

[0042] The content of the crystalline polyester resin in the binder resin composition for toner is preferably 2% by mass or more, and preferably 30% by mass or less, more preferably 25% by mass or less, and even more preferably 15% by mass or less.

[0043] The amorphous polyester resin contains an amorphous polyester resin (A) having a softening point of 80°C or higher and 120°C or lower.

[0044] The amorphous polyester resin (A) is preferably a polycondensate of an alcohol component and a carboxylic acid component containing an aromatic dicarboxylic acid compound.

[0045] The alcohol component has the formula (I):

[0046] [ka]

[0047] (wherein OR and RO are oxyalkylene groups, R is an ethylene group and / or a propylene group, x and y are the average number of moles of alkylene oxide added and are each a positive number, and the sum of x and y is 1 or more, preferably 1.5 or more, and 16 or less, preferably 8 or less, more preferably 6 or less, and even more preferably 4 or less.) It is preferable that the alkylene oxide adduct of bisphenol A represented by the following formula is contained.

[0048] 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.

[0049] The content of the alkylene oxide adduct of bisphenol A represented by formula (I) in the alcohol component is preferably 70 mol% or more, more preferably 80 mol% or more, even more preferably 90 mol% or more, and even more preferably 95 mol% or more, but 100 mol% or less.

[0050] 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, and glycerin.

[0051] Examples of aromatic dicarboxylic acid compounds include phthalic acid, isophthalic acid, terephthalic acid, etc. Among these, terephthalic acid is preferred.

[0052] The content of the aromatic dicarboxylic acid compound in the carboxylic acid component is preferably 30 mol% or more, more preferably 35 mol% or more, and even more preferably 40 mol% or more, and is 100 mol% or less, preferably 90 mol% or less, and more preferably 85 mol% or less.

[0053] Examples of the carboxylic acid component other than the aromatic dicarboxylic acid compound include an aliphatic dicarboxylic acid compound and a trivalent or higher carboxylic acid compound.

[0054] Examples of the aliphatic dicarboxylic acid compound include oxalic acid, malonic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, succinic acid which may be substituted with a hydrocarbon group, and adipic acid.

[0055] The content of the aliphatic dicarboxylic acid compound in the carboxylic acid component is 0 mol% or more, preferably 5 mol% or more, more preferably 10 mol% or more, even more preferably 15 mol% or more, and preferably 40 mol% or less, more preferably 30 mol% or less, even more preferably 25 mol% or less.

[0056] Examples of the trivalent or higher carboxylic acid compound include trimellitic acid, pyromellitic acid, anhydrides of these acids, and alkyl esters of these acids having 1 to 3 carbon atoms.

[0057] From the viewpoint of durability, the content of the trivalent or higher carboxylic acid compound in the carboxylic acid component is 0 mol% or more, preferably 1 mol% or more, more preferably 2 mol% or more, and is preferably 10 mol% or less, more preferably 8 mol% or less.

[0058] The alcohol component may contain a monohydric alcohol, and the carboxylic acid component may contain a monocarboxylic acid compound, as appropriate.

[0059] From the viewpoint of adjusting the softening point of the polyester resin, the equivalent ratio of the carboxyl groups of the carboxylic acid component to the hydroxyl groups of the alcohol component (COOH groups / OH groups) is preferably 0.6 or more, more preferably 0.7 or more, even more preferably 0.8 or more, and is preferably 1.3 or less, more preferably 1.2 or less.

[0060] The amorphous polyester resin (A) can be produced by polycondensing an alcohol and a carboxylic acid compound in the same manner as the crystalline polyester segment (c1). The polycondensation reaction temperature is preferably 160°C or higher, more preferably 200°C or higher, and preferably 250°C or lower, more preferably 240°C or lower.

[0061] In the present invention, the polyester resin may be modified to such an extent that its properties are not substantially impaired. Examples of modified polyester resins include polyester resins grafted or blocked with phenol, urethane, epoxy, or the like, by the methods described in JP-A Nos. 11-133668, 10-239903, and 8-20636.

[0062] The softening point of the amorphous polyester resin (A) is 80°C or higher, preferably 85°C or higher, more preferably 90°C or higher, from the viewpoint of storage stability, and 120°C or lower, preferably 115°C or lower, more preferably 110°C or lower, from the viewpoint of low-temperature fixability.

[0063] The glass transition temperature of the amorphous polyester resin (A) is preferably 45°C or higher, more preferably 50°C or higher, and even more preferably 53°C or higher from the viewpoint of heat-resistant storage stability, and is preferably 80°C or lower, more preferably 70°C or lower from the viewpoint of low-temperature fixability.

[0064] From the viewpoint of charging stability, the acid value of the amorphous polyester resin (A) is preferably 5 mgKOH / g or more, more preferably 10 mgKOH / g or more, and is preferably 40 mgKOH / g or less, more preferably 30 mgKOH / g or less.

[0065] From the viewpoint of charging stability, the hydroxyl value of the amorphous polyester resin (A) is preferably 20 mgKOH / g or more, more preferably 30 mgKOH / g or more, and preferably 80 mgKOH / g or less, more preferably 65 mgKOH / g or less.

[0066] The content of the amorphous polyester resin (A) in the amorphous polyester resin is preferably 50% by mass or more, more preferably 60% by mass or more, even more preferably 70% by mass or more, even more preferably 80% by mass or more, even more preferably 90% by mass or more, and even more preferably 95% by mass or more, but 100% by mass or less.

[0067] The amorphous polyester resin may contain an amorphous polyester resin (B) having a softening point exceeding 120° C., provided that the effects of the present invention are not impaired. The softening point of the amorphous polyester resin (B) is preferably 125° C. or higher, and preferably 160° C. or lower, more preferably 150° C. or lower, and even more preferably 140° C. or lower.

[0068] The amorphous polyester resin (B) can be obtained using the same raw material monomers (alcohol component and carboxylic acid component) as those for the amorphous polyester resin (A), except that the softening point is different.

[0069] The preferred glass transition temperature, acid value, and hydroxyl value of the amorphous polyester resin (B) are the same as those of the amorphous polyester resin (A).

[0070] The content of the amorphous polyester resin (A) in the binder resin composition for toner is preferably 40% by mass or more, more preferably 60% by mass or more, even more preferably 80% by mass or more, and preferably 98% by mass or less.

[0071] The content of the amorphous polyester resin in the binder resin composition for toner is preferably 70% by mass or more, more preferably 75% by mass or more, even more preferably 85% by mass or more, and preferably 98% by mass or less.

[0072] The mass ratio of the amorphous polyester resin (A) to the crystalline block polymer (C) (amorphous polyester resin (A) / crystalline block polymer (C)) is preferably 70 / 30 or more, more preferably 75 / 25 or more, and even more preferably 85 / 15 or more from the viewpoint of heat-resistant storage stability, and is preferably 98 / 2 or less from the viewpoint of low-temperature fixability.

[0073] Furthermore, the mass ratio of the amorphous polyester resin to the crystalline polyester resin (amorphous polyester resin / crystalline polyester resin) is preferably 70 / 30 or more, more preferably 75 / 25 or more, and even more preferably 85 / 15 or more from the viewpoint of heat-resistant storage stability, and is preferably 98 / 2 or less from the viewpoint of low-temperature fixability.

[0074] The binder resin composition for toner may contain a resin other than the amorphous polyester resin and the crystalline polyester resin as long as the effects of the present invention are not impaired. Examples of the other resin include vinyl resins such as styrene-acrylic resins, epoxy resins, polycarbonates, polyurethanes, and composite resins containing two or more of these resins.

[0075] The total content of the amorphous polyester resin (A) and the crystalline block polymer (C) in the binder resin composition for toner is preferably 60% 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 98% by mass or more, but is 100% by mass or less.

[0076] Furthermore, the total content of the crystalline polyester resin and the amorphous polyester resin in the binder resin composition for toner is preferably 80% by mass or more, more preferably 90% by mass or more, even more preferably 95% by mass or more, and still more preferably 98% by mass or more, and is 100% by mass or less.

[0077] Furthermore, the present invention provides a toner for developing electrostatic images, which contains the binder resin composition for toners of the present invention as a binder resin.

[0078] The content of the binder resin composition for toner in the toner is preferably 50% by mass or more, more preferably 60% by mass or more, even more preferably 70% by mass or more, and even more preferably 80% by mass or more, and is preferably less than 100% by mass, more preferably 99% by mass or less, even more preferably 98% by mass or less, and even more preferably 95% by mass or less.

[0079] The toner for developing electrostatic images of the present invention may contain additives such as a colorant, a release agent, a charge control agent, a magnetic powder, a flowability improver, a conductivity adjuster, a reinforcing filler such as a fibrous substance, an antioxidant, and a cleaning property improver in addition to the binder resin (binder resin composition for toner).

[0080] As the colorant, dyes, pigments, magnetic materials, etc. used as toner colorants can be used. Examples include carbon black, phthalocyanine blue, permanent brown FG, brilliant fast scarlet, pigment red 122, pigment green B, rhodamine-B base, solvent red 49, solvent red 146, solvent blue 35, quinacridone, carmine 6B, isoindoline, disazo yellow, etc. In the present invention, the toner may be either a black toner or a color toner.

[0081] 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.

[0082] Examples of the release agent include hydrocarbon waxes such as polypropylene wax, polyethylene wax, ethylene-propylene copolymer wax, microcrystalline wax, paraffin wax, and Fischer-Tropsch wax, and oxides thereof; ester waxes such as carnauba wax, montan wax, and deacidified waxes thereof, and fatty acid ester wax; fatty acid amides, fatty acids, higher alcohols, and fatty acid metal salts, and these may be used alone or in combination of two or more.

[0083] 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.

[0084] The content of the release agent is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, and even more preferably 1.5 parts by mass or more, relative to 100 parts by mass of the binder resin, from the viewpoints of the low-temperature fixability and offset resistance of the toner and the dispersibility in the binder resin, and is preferably 10 parts by mass or less, more preferably 8 parts by mass or less, and even more preferably 7 parts by mass or less.

[0085] 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.

[0086] Positively chargeable charge control agents include nigrosine dyes such as "Nigrosine Base EX," "Oil Black BS," "Oil Black SO," "Bontron N-01," "Bontron N-04," "Bontron N-07," "Bontron N-09," and "Bontron N-11" (all manufactured by Orient Chemical Industries Co., Ltd.); triphenylmethane dyes containing a tertiary amine as a side chain; quaternary ammonium salt compounds such as "Bontron P-51" (manufactured by Orient Chemical Industries Co., Ltd.), cetyltrimethylammonium bromide, and "COPY CHARGE PX Examples of suitable resins include polyamine resins such as "AFP-B" (manufactured by Orient Chemical Industries Co., Ltd.); imidazole derivatives such as "PLZ-2001" and "PLZ-8001" (both manufactured by Shikoku Chemical Industry Co., Ltd.); and styrene-acrylic resins such as "FCA-701PT" and "FCA-201-PS" (manufactured by Fujikura Chemical Industries Co., Ltd.).

[0087] Examples of negatively chargeable charge control agents include metal-containing azo dyes such as "Balifast Black 3804," "Bontron S-31," "Bontron S-32," "Bontron S-34," and "Bontron S-36" (all manufactured by Orient Chemical Industries, Ltd.), "Eisenspiron Black TRH," and "T-77" (manufactured by Hodogaya Chemical Co., Ltd.); metal compounds of benzilic acid compounds such as "LR-147" and "LR-297" (manufactured by Nippon Carlit Co., Ltd.); metal compounds of salicylic acid compounds such as "Bontron E-81," "Bontron E-84," "Bontron E-88," and "Bontron E-304" (all manufactured by Orient Chemical Industries, Ltd.), and "TN-105" (manufactured by Hodogaya Chemical Co., Ltd.); copper phthalocyanine dyes; and quaternary ammonium salts such as "COPY CHARGE NX VP434 (manufactured by Clariant), nitroimidazole derivatives, etc.; organometallic compounds, etc.

[0088] 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.

[0089] The toner of the present invention may be a toner obtained by any known method such as a melt-kneading method, an emulsion aggregation method, or a polymerization method, but from the viewpoint of dispersibility of the crystalline polyester resin, a pulverized toner obtained by a melt-kneading method is preferred. In the case of a pulverized toner obtained by a melt-kneading method, for example, raw materials such as a binder resin composition for a toner, a colorant, a release agent, and a charge control agent are uniformly mixed in a mixer such as a Henschel mixer, and then the mixture is melt-kneaded, cooled, pulverized, and classified to produce the toner.

[0090] The mixture to be melt-kneaded may be kneaded all at once or in portions, but it is preferable to mix the mixture in advance in a mixer such as a Henschel mixer or a ball mill and then supply it to the kneader. The amorphous polyester resin and the crystalline polyester resin may be mixed in advance, or each resin may be used directly or mixed with other raw materials.

[0091] The melt-kneading can be carried out using a known kneader such as an internal kneader, a single-screw or twin-screw extruder, or an open-roll kneader.

[0092] The melt-kneading temperature is not particularly limited as long as it is a temperature at which the resin melts and the raw materials are mixed together.

[0093] After the melt-kneading step, it is preferable to appropriately cool the kneaded product until it reaches a pulverizable hardness, and then, if necessary, perform a pulverization step and a classification step to obtain toner particles. Here, "cooling" means cooling the kneaded product to a temperature of 0°C or higher and 50°C or lower, or to a temperature below the glass transition temperature of the binder resin in the kneaded product.

[0094] In order to improve the transferability of the toner of the present invention, it is preferable to use an external additive. Examples of the external additive include inorganic fine particles such as silica, alumina, titania, zirconia, tin oxide, and zinc oxide, and organic fine particles such as melamine-based resin fine particles and polytetrafluoroethylene resin fine particles, and two or more of these may be used in combination. Among these, silica is preferred, and from the viewpoint of the transferability of the toner, hydrophobic silica that has been subjected to a hydrophobic treatment is more preferred.

[0095] Examples of hydrophobic treatment agents for hydrophobizing the surfaces of silica particles include hexamethyldisilazane (HMDS), dimethyldichlorosilane (DMDS), cyclic silazanes, silicone oils, aminosilanes, octyltriethoxysilane (OTES), and methyltriethoxysilane.

[0096] From the viewpoint of the chargeability, fluidity, and transferability of the toner, the average particle diameter of the external additive is preferably 10 nm or more, more preferably 15 nm or more, and is preferably 250 nm or less, more preferably 200 nm or less, and even more preferably 90 nm or less.

[0097] The external addition treatment by mixing the toner particles with the external additives can be carried out in accordance with a conventional method, and a mixer such as a Henschel mixer can be used.

[0098] From the viewpoint of the chargeability, fluidity, and transferability of the toner, the content of the external additive is preferably 0.05 parts by mass or more, more preferably 0.1 parts by mass or more, and even more preferably 0.3 parts by mass or more, relative to 100 parts by mass of the toner particles before treatment with the external additive, and is preferably 5 parts by mass or less, and more preferably 3 parts by mass or less.

[0099] The volume median particle size (D 50 ) is preferably 3 μm or more, more preferably 4 μm or more, and is preferably 15 μm or less, more preferably 10 μm or less. 50) means the particle size at which the cumulative volume frequency calculated by volume fraction is 50% counting from the smallest particle size. In addition, when the toner is treated with an external additive, the volume median particle size of the toner particles before treatment with the external additive is taken as the volume median particle size of the toner.

[0100] The toner of the present invention can be used as a toner for one-component development as it is, or as a toner for two-component development mixed with a carrier, in an image forming apparatus of a one-component development system or a two-component development system, respectively. [Example]

[0101] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. Physical properties of resins and the like can be measured by the following methods.

[0102] [Softening point of resin] Using a flow tester "CFT-500D" (Shimadzu Corporation), 1 g of sample is heated at a temperature increase rate of 6°C / min while applying a load of 1.96 MPa with the plunger, and extruding it from a nozzle 1 mm in diameter and 1 mm in length. The plunger depression distance of the flow tester is plotted against the temperature, and the temperature at which half of the sample flows out is taken as the softening point.

[0103] [Maximum endothermic peak temperature of resin] Using a differential scanning calorimeter "Q-100" (manufactured by TA Instruments Japan Co., Ltd.), 0.01 to 0.02 g of sample is weighed into an aluminum pan, cooled from room temperature (25°C) to 0°C at a rate of 10°C / min, and maintained at 0°C for 1 minute. Then, measurements are performed at a rate of 10°C / min. The temperature of the peak with the largest peak area among the observed endothermic peaks is taken as the maximum endothermic peak temperature.

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

[0105] [Acid value of resin] Measurements are made based on the method of JIS K 0070:1992, except that the measurement solvent is changed from the ethanol and ether mixture specified in JIS K 0070 to a mixture of acetone and toluene (acetone:toluene = 1:1 (volume ratio)) for amorphous resins, and to a mixture of chloroform and dimethylformamide (chloroform:dimethylformamide = 7:3 (volume ratio)) for crystalline resins.

[0106] [Hydroxyl value of resin] Measurement is performed based on the method of JIS K 0070:1992, except that the measurement solvent is changed from the ethanol and ether mixed solvent specified in JIS K 0070 to tetrahydrofuran.

[0107] [Melting point of release agent] Using a differential scanning calorimeter "DSC 210" (TA Instruments Japan Co., Ltd.), 0.01 to 0.02 g of sample is weighed into an aluminum pan, heated to 200°C at a heating rate of 10°C / min, and cooled from that temperature to -10°C at a cooling rate of 5°C / min. Next, the sample is heated to 180°C at a heating rate of 10°C / min and measured. The maximum endothermic peak temperature observed in the resulting melting endothermic curve is taken as the melting point of the release agent.

[0108] [Average particle size of external additives] The average particle size refers to the number-average particle size, and is calculated by measuring the particle sizes (average values ​​of major and minor axes) of 500 particles in a scanning electron microscope (SEM) photograph and averaging these values ​​by number.

[0109] [Volume Median Particle Size of Toner] Measuring instrument: Coulter Multisizer III (manufactured by Beckman Coulter, Inc.) Aperture diameter: 50 μm Analysis software: Multisizer III version 3.51 (Beckman Coulter, Inc.) Electrolyte: "Isoton (registered trademark) II" (manufactured by Beckman Coulter, Inc.) Dispersion: Polyoxyethylene lauryl ether "Emulgen (registered trademark) 109P" (manufactured by Kao Corporation, HLB (Griffin) = 13.6) dissolved in the electrolyte to adjust the concentration to 5% by mass Dispersion conditions: 10 mg of the measurement sample was added to 5 mL of the dispersion, and the mixture was dispersed for 1 minute using an ultrasonic disperser (machine name: US-1 manufactured by SND Corporation, output: 80 W). 25 mL of electrolyte was then added, and the mixture was further dispersed for 1 minute using the ultrasonic disperser to prepare a sample dispersion. Measurement conditions: The sample dispersion was added to 100 mL of the electrolyte to adjust the concentration so that the particle size of 30,000 particles could be measured in 20 seconds. Then, 30,000 particles were measured, and the volume median particle size (D 50 ) is found.

[0110] Resin manufacturing example 1 The alcohol components shown in Table 1, carboxylic acid components other than trimellitic anhydride, and an esterification catalyst were placed in a 10-liter four-neck flask equipped with a thermometer, a stainless steel stirring rod, a downflow condenser equipped with a dehydration tube, and a nitrogen inlet tube, and the mixture was heated to 230°C in a mantle heater under a nitrogen atmosphere and reacted for 8 hours. Then, trimellitic anhydride was added and the reaction was continued at 220°C for 2 hours, and the reaction was continued at 8 kPa until the softening point shown in Table 1 was reached, yielding amorphous resins (Resins A1, A5, and B1).

[0111] Resin manufacturing example 2 The alcohol components shown in Table 1, carboxylic acid components other than trimellitic anhydride, and an esterification catalyst were placed in a 10-liter four-neck flask equipped with a thermometer, a stainless steel stirring rod, a downflow condenser equipped with a dehydration tube, and a nitrogen inlet tube, and the temperature was raised from 180°C to 230°C over 6 hours in a nitrogen atmosphere in a mantle heater, and the reaction was carried out at 230°C for 4 hours. Thereafter, trimellitic anhydride was added and the reaction was carried out at 220°C for 2 hours, and the reaction was continued at 8 kPa until the softening point shown in Table 1 was reached, yielding amorphous resins (Resins A2 and A3).

[0112] Resin manufacturing example 3 The alcohol component, carboxylic acid component, and esterification catalyst shown in Table 1 were placed in a 10-liter four-neck flask equipped with a thermometer, a stainless steel stirring rod, a downflow condenser equipped with a dehydration tube, and a nitrogen inlet tube, and the mixture was heated to 230°C in a nitrogen atmosphere in a mantle heater and reacted for 8 hours. The reaction was then continued at 8 kPa until the softening point shown in the table was reached, yielding an amorphous resin (Resin A4).

[0113] [Table 1]

[0114] Resin manufacturing example 4 The alcohol and carboxylic acid components shown in Table 2 were placed in a 10-liter four-neck flask equipped with a thermometer, a stainless steel stirring rod, a downflow condenser, and a nitrogen inlet tube, and the mixture was heated to 200°C over 8 hours in a nitrogen atmosphere in a mantle heater. The esterification catalyst shown in Table 2 was then added, and the reaction was carried out at 8 kPa for 1 hour to obtain a crystalline polyester segment. ε-Caprolactone was then added at 100°C and the reaction was carried out at the same temperature for 2 hours, and then the reaction was continued at 8 kPa until the softening point shown in Table 2 was reached, obtaining crystalline block polymers (resins C1 to C5, C7).

[0115] Resin manufacturing example 5 The alcohol component and carboxylic acid component shown in Table 2 were placed in a 10-liter four-neck flask equipped with a thermometer, a stainless steel stirring rod, a downflow condenser, and a nitrogen inlet tube, and the temperature was raised to 200°C over 8 hours in a nitrogen atmosphere in a mantle heater. Then, an esterification catalyst shown in Table 2 was added, and the reaction was carried out at 8 kPa until the softening point shown in Table 2 was reached, yielding a crystalline polyester resin (resin C6).

[0116] [Table 2]

[0117] Examples 1 to 12 and Comparative Examples 1 to 3 100 parts by mass of the binder resin composition shown in Table 3, 5 parts by mass of colorant "ECB-301" (Dainichiseika Color & Chemicals Co., Ltd., Phthalocyanine Blue), 1 part by mass of charge control agent "LR-147" (Nippon Carlit Co., Ltd.), and 3 parts by mass of release agent "Carnauba Wax C1" (Kato Yoko Co., Ltd., melting point: 80°C) were thoroughly stirred in a Henschel mixer and then melt-kneaded using a co-rotating twin-screw extruder with a kneading section having a total length of 1560 mm, a screw diameter of 42 mm, and a barrel inner diameter of 43 mm. The roll rotation speed was 200 r / min, the heating temperature inside the roll was set to 90°C, the temperature of the kneaded material was 140°C, the kneaded material was fed at a rate of 10 kg / h, and the average residence time was approximately 18 seconds. The obtained kneaded product was cooled from 140°C to 50°C in 1.5 hours, rolled and cooled at 50°C with a cooling roller, and then left to stand at 45°C for 4 hours. Thereafter, it was pulverized in a jet mill, classified, and the volume median particle size (D 50 ) Toner particles of 5.5 μm were obtained.

[0118] To 100 parts by mass of the obtained toner particles, 1.5 parts by mass of hydrophobic silica "Aerosil R-972" (manufactured by Nippon Aerosil Co., Ltd., hydrophobic treatment agent: DMDS, average particle size: 16 nm) and 1 part by mass of hydrophobic silica "RY-50" (manufactured by Nippon Aerosil Co., Ltd., hydrophobic treatment agent: silicone oil, average particle size: 40 nm) were added as external additives, and the mixture was mixed in a Henschel mixer at 3600 r / min for 5 minutes to perform external additive treatment and obtain a toner.

[0119] Test example [Durability] (1) Immediately after production Toner 24 hours after manufacture was loaded onto a laser printer "PagePresto N-4" (manufactured by Casio Computer Co., Ltd., fixing: contact fixing method, development: non-magnetic single-component development 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 a temperature of 25°C and a relative humidity of 40%. During the printing, a black solid image was printed every 500 sheets, and the image was checked for streaks. The number of sheets printed until streaks were visually observed on the image was taken as the number of sheets on which streaks appeared due to the toner fusing and adhering to the developing roll, and durability was evaluated. The results are shown in Table 3. The more sheets printed until streaks were first visually observed on the image, the better the durability of the toner.

[0120] (2) After long-term storage The produced toner was filled into a cartridge and stored in a constant temperature and humidity chamber at a temperature of 25°C and a relative humidity of 40% for 30 days. Thereafter, durability was evaluated in the same manner as in (1). The results are shown in Table 3.

[0121] [Table 3]

[0122] The above results show that, compared to Comparative Example 1, which used a crystalline polyester resin that was not a block polymer, Comparative Example 2, in which the softening point of the amorphous polyester resin was too high, and Comparative Example 3, in which a crystalline block polymer was used in which the carboxylic acid component of the crystalline polyester segment did not contain an aliphatic dicarboxylic acid compound, all of Examples 1 to 12 were able to maintain good durability even after long-term storage. [Industrial Applicability]

[0123] The toner for developing electrostatic images containing the binder resin composition for toner 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 toners, comprising a crystalline polyester resin and an amorphous polyester resin, wherein the crystalline polyester resin comprises a crystalline block polymer (C) in which a crystalline polyester segment (c1), which is a polycondensate of an alcohol component containing an aliphatic diol and a carboxylic acid component containing an aliphatic dicarboxylic acid compound, and a crystalline polyester segment (c2), which is obtained by ring-opening polymerization of a cyclic lactone, are bonded via an ester bond, and the amorphous polyester resin comprises an amorphous polyester resin (A) having a softening point of 80°C or higher and 120°C or lower.

2. 2. The binder resin composition for toner according to claim 1, wherein the total content of the crystalline polyester resin and the amorphous polyester resin is 80% by mass or more and 100% by mass or less.

3. The SP value of the crystalline polyester segment (c1) is 9.2 (cal / cm ３ ) １／２ More than 11.0 (cal / cm ３ ) １／２ 3. The binder resin composition for toner according to claim 1, wherein:

4. 3. The binder resin composition for toner according to claim 1, wherein the cyclic lactone is ε-caprolactone.

5. 3. The binder resin composition for toner according to claim 1, wherein in the crystalline block polymer (C), a mass ratio of the crystalline polyester segment (c1) to the crystalline polyester segment (c2) (crystalline polyester segment (c1) / crystalline polyester segment (c2)) is 10 / 90 or more and 90 / 10 or less.

6. 3. The binder resin composition for toner according to claim 1, wherein the content of the crystalline block polymer (C) is 2% by mass or more and 30% by mass or less.

7. 3. A method for producing a binder resin composition for toner according to claim 1, wherein a crystalline polyester resin and an amorphous polyester resin are mixed together, and the crystalline polyester resin contains a crystalline block polymer (C) obtained by ring-opening polymerization of a cyclic lactone at a temperature of 80°C or higher and 120°C or lower with a crystalline polyester segment (c1), which is a polycondensate of an alcohol component containing an aliphatic diol and a carboxylic acid component containing an aliphatic dicarboxylic acid compound.

8. 3. A toner for developing electrostatic images, comprising the binder resin composition for toner according to claim 1.

Images