Binder resin composition for positively chargeable toner

Abstract

To provide a binder resin composition for a positively chargeable toner which is excellent in positive charging property, and can improve image quality of a printed matter such as thin line reproducibility by being used in an electrophotographic toner.SOLUTION: A binder resin composition for a positively chargeable toner contains a composite resin (A) containing a polyester resin segment which is a polycondensate of an alcohol component and a carboxylic acid component, and a vinyl-based resin segment which is an addition polymerization product of a raw material monomer containing a styrenic compound, and a modified polyester resin (B) which is a condensate of an amorphous polyester resin having an acid group and an amine compound, wherein the amine compound is at least one or more selected from 2-diethyl aminoethanol and 2-dibutyl aminoethanol.SELECTED DRAWING: None

Description

[Technical field]

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

[0002] In the field of electrophotography, with the development of electrophotographic systems, there is a demand for the development of toners that can handle higher image quality and higher speeds. Further, there are negatively charged toners and positively charged toners. In recent years, electrophotographic devices using positively charged toners have been preferably used since they generate less ozone, are free of odors due to ozone generation, and provide good charging properties.

[0003] Patent Document 1 describes a toner for developing electrostatic images, which includes a colorant, a resin composition obtained by condensing an amorphous polyester resin having an acid group with an amine compound, and one or more ester compositions selected from an ester composition (CI) containing a condensate of a carboxylic acid component containing 20 mol % or more of an aliphatic monocarboxylic acid compound and an alcohol component containing 90 mol % or more of a divalent or higher aliphatic alcohol, and an ester composition (CII) containing a condensate of an alcohol component containing 20 mol % or more of an aliphatic monoalcohol and a carboxylic acid component containing 90 mol % or more of a divalent or higher aliphatic carboxylic acid compound. Patent Document 2 describes a dry toner obtained by dissolving or dispersing at least a polyester resin (I) having an amino group, a polyester resin (II) having an anionic functional group, and a colorant in an organic solvent, dispersing the oil phase obtained in an aqueous medium, removing the solvent, and drying the resulting toner. Patent Document 3 describes a dry toner using a polyester in which at least a part of the COOH is replaced by a functional group containing N, such as amine, ammonium, betaine, pyridinium salt, or azine. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2021-47403 [Patent Document 2] JP 2009-217183 A [Patent Document 3] Japanese Patent Application Publication No. 14644 / 1983 Summary of the Invention [Problem to be solved by the invention]

[0005] However, there is a demand for further improvement in image quality in response to higher image quality and higher speeds. The present invention relates to a binder resin composition for positively charged toners, which has excellent positive charging properties and can improve the image quality of printed matter, such as fine line reproducibility, when used in electrophotographic toners. [Means for solving the problem]

[0006] The present inventors have found that the above-mentioned problems can be solved by a binder resin composition for positively charged toner, which contains a composite resin (A) including a polyester resin segment and a vinyl resin segment, and a modified polyester resin (B) which is a condensate of an amorphous polyester resin having an acid group, and at least one amine compound selected from 2-diethylaminoethanol and 2-dibutylaminoethanol.

[0007] That is, the present invention relates to the following [1] and [2]. [1] A composite resin (A) including a polyester resin segment which is a polycondensation product of an alcohol component and a carboxylic acid component, and a vinyl resin segment which is an addition polymerization product of a raw material monomer including a styrene compound; A binder resin composition for a positively charged toner, comprising a modified polyester resin (B) which is a condensation product of an amorphous polyester resin having an acid group and an amine compound, The binder resin composition for positively charged toner, wherein the amine compound is at least one selected from the group consisting of 2-diethylaminoethanol and 2-dibutylaminoethanol. [2] An electrophotographic toner comprising the binder resin composition for positively charged toners according to [1]. Effect of the Invention

[0008] According to the present invention, it is possible to provide a binder resin composition for a positively charged toner, which has excellent positive charging properties and can improve the image quality of printed matter, such as fine line reproducibility, when used in a toner for electrophotography. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] [Binder resin composition for positively charged toner] The binder resin composition for positively charged toner of the present invention is a binder resin composition for positively charged toner, which contains a composite resin (A) including a polyester resin segment which is a polycondensate of an alcohol component and a carboxylic acid component, and a vinyl resin segment which is an addition polymerization product of a raw material monomer including a styrene compound, and a modified polyester resin (B) which is a condensate of a non-crystalline polyester resin having an acid group and an amine compound, wherein the amine compound is at least one selected from 2-diethylaminoethanol and 2-dibutylaminoethanol. By having the above-mentioned constitution, a binder resin composition for a positively charged toner is obtained which has excellent positive charging properties and can improve the image quality of printed matter, such as fine line reproducibility, when used in a toner for electrophotography. The reason for this is unclear, but is thought to be as follows.

[0010] The binder resin composition for a positively charged toner of the present invention contains a composite resin (A) including a polyester resin segment and a vinyl resin segment which is an addition polymer of a raw material monomer including a styrene-based compound, and a modified polyester resin (B) which is a condensation product of a non-crystalline polyester resin having an acid group and an amine compound. A composite resin in which a charge retention portion composed of a raw material monomer with a high aromatic ring concentration such as a styrene-based compound is combined with a positively charged portion such as an amine compound in the molecule is quickly positively charged by the positively charged portion and retains a positive charge for a long period of time by the charge retention portion, which is advantageous for forming a positively charged toner. However, when an amine compound is introduced into a composite resin containing a polyester resin segment and a vinyl resin segment which is an addition polymer of a raw material monomer containing a styrene-based compound, the amine compound may not be effectively introduced into the composite resin due to steric hindrance or the like. In addition, it is thought that the positive charging property of the composite resin can be further enhanced by making the amino group of the amine compound to be introduced a tertiary amino group substituted with an electron-donating alkyl group, but in this case too, the steric hindrance of the amine compound due to the tertiary amino group may increase, which may lead to a decrease in the reaction rate with the composite resin. In contrast, in the present invention, it has been found that the charge retention effect is improved by combining a modified polyester resin (B), which is a condensation product of at least one selected from 2-diethylaminoethanol and 2-dibutylaminoethanol, which can introduce a tertiary amino group as an amine compound, and an amorphous polyester resin having an acid group, with a composite resin (A) containing a polyester resin segment and a vinyl resin segment, and allowing them to coexist in a toner. Since the polyester resin segment of the composite resin (A) and the modified polyester resin (B) have high affinity, the resins in the toner particles are compatible with each other, and the charge retention site of the composite resin (A) and the positively charged site of the modified polyester resin (B) are located in extremely close proximity to each other, which is thought to improve the positive chargeability of the toner in the same way as when a resin having a charge retention site and a positively charged site in the molecule is used. As a result, the positive chargeability of the toner is improved, and the image quality of the printed matter, such as fine line reproducibility, is thought to be improved.

[0011] The definitions of various terms used in this specification are given below. Whether a resin is crystalline or amorphous is determined by the crystallinity index. The crystallinity index is defined as the ratio of the softening point of the resin to the endothermic maximum peak temperature (softening point (°C) / endothermic maximum peak temperature (°C)) in the measurement method described in the Examples below. A crystalline resin is a resin with a crystallinity index of 0.6 or more and 1.4 or less. An amorphous resin is a resin in which no endothermic peak is observed, or in which the crystallinity index is greater than 1.4 or less than 0.6 when an endothermic peak is observed. The crystallinity index can be appropriately adjusted depending on the type and ratio of raw material monomers, as well as production conditions such as reaction temperature, reaction time, and cooling rate. The endothermic maximum peak temperature refers to the temperature of the endothermic peak with the largest peak area among the endothermic peaks observed under the conditions of the measurement method described in the Examples. In the specification, the carboxylic acid component of the polyester resin includes not only the exemplified compounds, but also anhydrides that decompose during the reaction to produce an acid, and alkyl esters of each carboxylic acid (alkyl groups having 1 to 3 carbon atoms). In the present specification, the term "binder resin composition" refers to a resin component contained in a toner that contains a condensate.

[0012] <Composite resin (A)> The composite resin (A) contains a polyester resin segment which is a polycondensation product of an alcohol component and a carboxylic acid component, and a vinyl resin segment which is an addition polymerization product of a raw material monomer including a styrene compound. The composite resin (A) is preferably amorphous.

[0013] [Polyester resin segment] Examples of the alcohol component of the polyester resin segment include alkylene oxide adducts of aromatic diols, linear or branched aliphatic diols, alicyclic diols, and trihydric or higher polyhydric alcohols. Among these, alkylene oxide adducts of aromatic diols are preferred from the viewpoint of improving the positive chargeability of the binder resin composition for positively chargeable toners.

[0014] The alkylene oxide adduct of an aromatic diol is preferably an alkylene oxide adduct of bisphenol A, more preferably an alkylene oxide adduct of formula (I):

[0015] [ka] (In the formula, OR 1 and R 2 O is an oxyalkylene group, and R 1 and R 2 are each independently an ethylene group or a propylene group, x and y are each an 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 and 16 or less.

[0016] Examples of the alkylene oxide adduct of bisphenol A include a propylene oxide adduct of bisphenol A [2,2-bis(4-hydroxyphenyl)propane] and an ethylene oxide adduct of bisphenol A. These may be used alone or in combination of two or more. From the viewpoint of improving the positive chargeability of the binder resin composition for a positively chargeable toner, the content of the alkylene oxide adduct of bisphenol A in the alcohol component is preferably 70 mol % or more, more preferably 90 mol % or more, even more preferably 95 mol % or more, and is 100 mol % or less, even more preferably 100 mol %.

[0017] Examples of linear or branched aliphatic diols include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 2,3-butanediol, 2,2-dimethyl-1,3-propanediol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, and 1,12-dodecanediol. Examples of alicyclic diols include hydrogenated bisphenol A [2,2-bis(4-hydroxycyclohexyl)propane] and alkylene oxide adducts of hydrogenated bisphenol A having 2 to 4 carbon atoms (average number of moles added: 2 to 12). Examples of trihydric or higher polyhydric alcohols include glycerin, pentaerythritol, trimethylolpropane, and sorbitol. These alcohol components may be used alone or in combination of two or more.

[0018] Examples of the carboxylic acid component of the polyester resin segment include dicarboxylic acids and trivalent or higher polyvalent carboxylic acids.

[0019] Dicarboxylic acids include, for example, aromatic dicarboxylic acids, aliphatic dicarboxylic acids, and alicyclic dicarboxylic acids. Examples of aromatic dicarboxylic acids include phthalic acid, terephthalic acid, and isophthalic acid. Among these, terephthalic acid and isophthalic acid are preferred, and terephthalic acid is more preferred. Examples of aliphatic dicarboxylic acids include oxalic acid, malonic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, succinic acid, pentanedioic acid, adipic acid, sebacic acid, dodecanedioic acid, azelaic acid, and succinic acid substituted with an aliphatic hydrocarbon group having from 1 to 20 carbon atoms. An example of the alicyclic dicarboxylic acid is cyclohexanedicarboxylic acid.

[0020] Examples of trivalent or higher polyvalent carboxylic acids include 1,2,4-benzenetricarboxylic acid (trimellitic acid), 2,5,7-naphthalenetricarboxylic acid, and pyromellitic acid.

[0021] Of these, the carboxylic acid component preferably includes an aromatic dicarboxylic acid and a trivalent or higher polyvalent carboxylic acid, and more preferably includes terephthalic acid and trimellitic acid. From the viewpoint of improving the positive chargeability of the binder resin composition for a positively chargeable toner, the amount of the aromatic dicarboxylic acid in the carboxylic acid component is preferably 60 mol % or more, more preferably 65 mol % or more, even more preferably 70 mol % or more, and is preferably 95 mol % or less, more preferably 90 mol % or less, even more preferably 85 mol % or less. In addition, the amount of the trivalent or higher polyvalent carboxylic acid in the carboxylic acid component is, from the viewpoint of improving the positive chargeability of the binder resin composition for a positively chargeable toner, preferably 5 mol % or more, more preferably 10 mol % or more, even more preferably 15 mol % or more, and is preferably 40 mol % or less, more preferably 35 mol % or less, even more preferably 30 mol % or less.

[0022] 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, and is preferably 1.3 or less, more preferably 1.2 or less.

[0023] [Vinyl resin segment] The vinyl resin segment is an addition polymer of raw material monomers including a styrene compound. Examples of the styrene-based compound include unsubstituted or substituted styrene. Examples of the substituent substituted on styrene include an alkyl group having 1 to 5 carbon atoms, a halogen atom, an alkoxy group having 1 to 5 carbon atoms, a sulfonic acid group, or a salt thereof. Examples of styrene-based compounds include styrene, methylstyrene, α-methylstyrene, β-methylstyrene, tert-butylstyrene, chlorostyrene, chloromethylstyrene, methoxystyrene, styrenesulfonic acid, and salts thereof. Among these, styrene is preferred. In the raw material monomers of the vinyl resin segment, the content of the styrene-based compound is preferably 70% by mass or more, more preferably 80% by mass or more, even more preferably 90% by mass or more, and is 100% by mass or less, even more preferably 100% by mass, from the viewpoint of improving the positive chargeability of the binder resin composition for a positively chargeable toner.

[0024] When the raw material monomer constituting the vinyl resin segment contains a raw material monomer other than a styrene compound, the raw material monomer may be, for example, (meth)acrylic acid esters such as alkyl (meth)acrylate, benzyl (meth)acrylate, and dimethylaminoethyl (meth)acrylate; olefins such as ethylene, propylene, and butadiene; halovinyls such as vinyl chloride; vinyl esters such as vinyl acetate and vinyl propionate; vinyl ethers such as methyl vinyl ether; vinylidene halides such as vinylidene chloride; and N-vinyl compounds such as N-vinylpyrrolidone. Among these, (meth)acrylic acid esters are preferred, and alkyl (meth)acrylates are more preferred. The number of carbon atoms in the alkyl group in the alkyl (meth)acrylate is preferably 1 or more, more preferably 4 or more, even more preferably 6 or more, and is preferably 24 or less, more preferably 22 or less, even more preferably 20 or less. Examples of the alkyl (meth)acrylate include methyl (meth)acrylate, ethyl (meth)acrylate, (iso)propyl (meth)acrylate, (iso or tertiary)butyl (meth)acrylate, (iso)amyl (meth)acrylate, cyclohexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, (iso)octyl (meth)acrylate, (iso)decyl (meth)acrylate, (iso)dodecyl (meth)acrylate, (iso)palmityl (meth)acrylate, (iso)stearyl (meth)acrylate, and (iso)behenyl (meth)acrylate. Of these, 2-ethylhexyl (meth)acrylate or stearyl (meth)acrylate is preferred, 2-ethylhexyl acrylate and stearyl (meth)acrylate are more preferred, and 2-ethylhexyl acrylate is even more preferred. In addition, "(iso or tertiary)" and "(iso)" refer to both the presence and absence of these prefixes, and the absence of these prefixes indicates normal. In addition, "(meth)acrylic acid" refers to acrylic acid or methacrylic acid.

[0025] [Constituent units derived from bireactive monomers] The composite resin (A) preferably has a structural unit derived from a bireactive monomer bonded to a polyester resin segment and a vinyl resin segment via a covalent bond. The term "structural unit derived from a bireactive monomer" refers to a unit formed by reaction of a functional group and an addition polymerizable group of a bireactive monomer. An example of the addition polymerizable group is a carbon-carbon unsaturated bond (ethylenically unsaturated bond). Examples of the bireactive monomer include addition polymerizable monomers having at least one functional group selected from a hydroxyl group, a carboxyl group, an epoxy group, a primary amino group, and a secondary amino group in the molecule. Among these, from the viewpoint of reactivity, addition polymerizable monomers having at least one functional group selected from a hydroxyl group and a carboxyl group are preferred, and addition polymerizable monomers having a carboxyl group are more preferred. Examples of the addition polymerizable monomer having a carboxy group include acrylic acid, methacrylic acid, fumaric acid, and maleic acid. Among these, from the viewpoint of reactivity in both the polycondensation reaction and the addition polymerization reaction, acrylic acid and methacrylic acid are preferred, and acrylic acid is more preferred. When the bireactive monomer is an addition polymerizable monomer having a carboxy group, the amount of the constitutional units derived from the bireactive monomer is preferably 1 mol part or more, more preferably 2 mol parts or more, even more preferably 4 mol parts or more, and preferably 15 mol parts or less, more preferably 12 mol parts or less, even more preferably 10 mol parts or less, relative to 100 mol parts of the alcohol component of the polyester resin segment of the composite resin (A).

[0026] The content of the vinyl resin segment in the composite resin (A) is preferably 5 mass% or more, more preferably 10 mass% or more, even more preferably 15 mass% or more, and preferably 45 mass% or less, more preferably 35 mass% or less, even more preferably 25 mass% or less, based on the total amount of the polyester resin segment and the vinyl resin segment. The content of the polyester resin segment in the composite resin (A) is preferably 55% by mass or more, more preferably 65% ​​by mass or more, even more preferably 75% by mass or more, and preferably 95% by mass or less, more preferably 90% by mass or less, even more preferably 85% by mass or less, based on the total amount of the polyester resin segment and the vinyl resin segment. Note that the constitutional unit derived from the bireactive monomer is included in the polyester resin segment in the calculation.

[0027] The content of the structural units derived from the bireactive monomer in the composite resin (A) is preferably 0.1 mass% or more, more preferably 0.2 mass% or more, and even more preferably 0.3 mass% or more, relative to the total amount of the polyester resin segment and the vinyl resin segment, and is preferably 10 mass% or less, more preferably 7 mass% or less, and even more preferably 4 mass% or less.

[0028] The above amount is calculated based on the ratio of the amounts of the polyester resin segment, the raw material monomer for the vinyl resin segment, the bireactive monomer, and the radical polymerization initiator, and the mass of the polyester resin segment, etc. is based on the mass excluding the mass of water generated by polycondensation. When a radical polymerization initiator is used, the mass of the radical polymerization initiator is calculated by including it in the vinyl resin segment.

[0029] [Method for producing composite resin (A)] The composite resin (A) may be produced, for example, by a method including a step A of polycondensing an alcohol component and a carboxylic acid component, and a step B of addition polymerizing raw material monomers for a vinyl resin segment and a bireactive monomer. Step B may be carried out after step A, step B may be carried out after step A, or step A and step B may be carried out simultaneously. A method is preferred in which a part of the carboxylic acid component is subjected to a polycondensation reaction in step A, and then step B is carried out, and thereafter the remainder of the carboxylic acid component is added to the polymerization system to further proceed with the polycondensation reaction in step A and the polycondensation reaction with the carboxy group of the bireactive monomer or the constituent moiety derived from the bireactive monomer.

[0030] In step A, if necessary, polycondensation may be performed using an esterification catalyst such as tin(II) di(2-ethylhexanoate), dibutyltin oxide, titanium diisopropoxybis(triethanolaminate) in an amount of 0.01 part by mass or more and 5 parts by mass or less per 100 parts by mass of the total amount of the alcohol component and the carboxylic acid component, and an esterification promoter such as gallic acid (same as 3,4,5-trihydroxybenzoic acid) in an amount of 0.001 part by mass or more and 0.5 part by mass or less per 100 parts by mass of the total amount of the alcohol component and the carboxylic acid component. When a monomer having an unsaturated bond such as fumaric acid is used in polycondensation, a radical polymerization inhibitor may be used, if necessary, in an amount of preferably 0.001 to 0.5 parts by mass per 100 parts by mass of the total amount of the alcohol component and the carboxylic acid component. An example of the radical polymerization inhibitor is 4-tert-butylcatechol. The temperature of the polycondensation reaction is preferably 120° C. or higher, more preferably 130° C. or higher, and even more preferably 140° C. or higher, and is preferably 250° C. or lower, and more preferably 240° C. or lower. The polycondensation may be carried out in an inert gas atmosphere.

[0031] Examples of the radical polymerization initiator for the addition polymerization in step B include peroxides such as dibutyl peroxide, persulfates such as sodium persulfate, and azo compounds such as 2,2'-azobis(2,4-dimethylvaleronitrile). The amount of the radical polymerization initiator used is preferably 1 part by mass or more and 20 parts by mass or less based on 100 parts by mass of the raw material monomer of the vinyl resin segment. The temperature of the addition polymerization is preferably 110° C. or higher, more preferably 130° C. or higher, and preferably 230° C. or lower, more preferably 220° C. or lower, and further preferably 210° C. or lower.

[0032] [Physical properties of composite resin (A)] The glass transition temperature of the composite resin (A) is preferably 40° C. or higher, more preferably 45° C. or higher, and even more preferably 50° C. or higher, and from the viewpoint of further improving low-temperature fixability, is preferably 80° C. or lower, more preferably 75° C. or lower, and even more preferably 70° C. or lower. The softening point of the composite resin (A) is preferably 120°C or higher, more preferably 125°C or higher, and even more preferably 130°C or higher, and from the viewpoint of further improving low-temperature fixability, is preferably 170°C or lower, more preferably 160°C or lower, and even more preferably 150°C or lower.

[0033] The glass transition temperature and softening point of the composite resin (A) can be appropriately adjusted by the type and amount of raw material monomer used, as well as production conditions such as reaction temperature, reaction time, and cooling rate, and these values ​​can be determined by the method described in the examples. When two or more types of composite resins (A) are used in combination, the glass transition temperature and softening point of the mixture obtained preferably fall within the above-mentioned ranges.

[0034] In the binder resin composition for positively charged toner, the content of the composite resin (A) is, from the viewpoint of increasing the positive chargeability and improving the fine line reproducibility, preferably 30% by mass or more, more preferably 35% by mass or more, even more preferably 40% by mass or more, and is preferably 70% by mass or less, more preferably 65% ​​by mass or less, even more preferably 60% by mass or less.

[0035] <Modified polyester resin (B)> The modified polyester resin (B) is a condensation product of an amorphous polyester resin having an acid group and an amine compound. From the viewpoint of improving the positive chargeability of the binder resin composition for a positively chargeable toner, the modified polyester resin (B) is preferably a resin having a softening point different from that of the composite resin (A), and more preferably a resin having a softening point lower than that of the composite resin (A). The difference in softening point between the composite resin (A) and the modified polyester resin (B) is preferably 5° C. or more, more preferably 15° C. or more, and even more preferably 25° C. or more from the viewpoint of improving the positive chargeability of the binder resin composition for a positively chargeable toner, and is preferably 50° C. or less, more preferably 45° C. or less, and even more preferably 40° C. or less from the viewpoint of the low-temperature fixing property of the toner.

[0036] [Amorphous polyester resin having an acid group] The amorphous polyester resin having an acid group is a polycondensation product of raw material monomers containing an alcohol component and a carboxylic acid component.

[0037] The alcohol component of the amorphous polyester resin having an acid group may be an alkylene oxide adduct of an aromatic diol, a linear or branched aliphatic diol, an alicyclic diol, or a trihydric or higher polyhydric alcohol, similar to the alcohol component of the polyester resin segment of the composite resin (A) described above, and among these, from the viewpoint of obtaining a toner having excellent low-temperature fixing properties, an alkylene oxide adduct of an aromatic diol is preferred, an alkylene oxide adduct of bisphenol A is more preferred, and a propylene oxide adduct of bisphenol A [2,2-bis(4-hydroxyphenyl)propane] and an ethylene oxide adduct of bisphenol A are even more preferred. These may be used alone or in combination of two or more.

[0038] Examples of the carboxylic acid component of the amorphous polyester resin having an acid group include dicarboxylic acids and trivalent or higher polyvalent carboxylic acids similar to the carboxylic acid components of the polyester resin segments described above. Among these, aromatic dicarboxylic acids are preferred, and it is more preferred to use an aromatic dicarboxylic acid in combination with a trivalent or higher polyvalent carboxylic acid. From the viewpoint of improving the positive chargeability of the binder resin composition for a positively chargeable toner, the amount of the aromatic dicarboxylic acid in the carboxylic acid component is preferably 70 mol % or more, more preferably 75 mol % or more, even more preferably 80 mol % or more, and is 100 mol % or less, preferably 95 mol % or less. In addition, the amount of the trivalent or higher polyvalent carboxylic acid in the carboxylic acid component is preferably 5 mol % or more, and is preferably 30 mol % or less, more preferably 25 mol % or less, and even more preferably 20 mol % or less, from the viewpoint of improving the positive chargeability of the binder resin composition for a positively chargeable toner. These carboxylic acid components may be used alone or in combination of two or more.

[0039] 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, and is preferably 1.3 or less, more preferably 1.2 or less. By setting the equivalent ratio of the carboxyl group of the carboxylic acid component to the hydroxyl group of the alcohol component within the above range, an amorphous polyester resin having an acid group can be obtained when raw material monomers containing an alcohol component and a carboxylic acid component are polycondensed.

[0040] [Amine Compound] The amine compound is at least one selected from 2-diethylaminoethanol and 2-dibutylaminoethanol, and is preferably 2-diethylaminoethanol or 2-dibutylaminoethanol. 2-Diethylaminoethanol and 2-dibutylaminoethanol have high reactivity with amorphous polyester resins having acid groups, and can efficiently produce modified polyester resin (B). In addition, since 2-diethylaminoethanol and 2-dibutylaminoethanol have an alkyl group that is an electron-donating group, the modified polyester resin (B) of the present invention can further improve the positive chargeability of the toner compared with polyester resins modified with amine compounds that do not have an alkyl group.

[0041] The content of the amine compound-derived structural unit in the modified polyester resin (B) is preferably 0.5% by mass or more, more preferably 1% by mass or more, even more preferably 1.5% by mass or more, and is preferably 10% by mass or less, more preferably 8% by mass or less, even more preferably 5% by mass or less, from the viewpoint of improving the positive chargeability of the binder resin composition for positively chargeable toner. The mass of the modified polyester resin (B) is based on the mass excluding the mass of water generated by the reaction.

[0042] [Method for producing modified polyester resin (B)] The modified polyester resin (B) can be produced, for example, by a method including a step of polycondensing an alcohol component and a carboxylic acid component to obtain an amorphous polyester resin having an acid group, and a step of condensing the acid group of the amorphous polyester resin with a hydroxyl group of an amine compound. The step of obtaining an amorphous polyester resin having an acid group by polycondensing an alcohol component and a carboxylic acid component is the same as step A described in the production method of composite resin (A), and the preferred ranges are also the same.

[0043] The condensation of the acid group-containing amorphous polyester resin and the amine compound can be carried out by heating them and removing water produced by the dehydration reaction from the system under reduced pressure or the like. The temperature of the condensation reaction is preferably 120° C. or higher, more preferably 130° C. or higher, and even more preferably 140° C. or higher, and is preferably 250° C. or lower, more preferably 230° C. or lower, and even more preferably 210° C. or lower. The condensation may be carried out in an inert gas atmosphere.

[0044] In the production of the modified polyester resin (B), the amount of the amine compound to be added is, from the viewpoint of improving the positive chargeability of the binder resin composition for a positively chargeable toner, 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, relative to 100 parts by mass of the total of the alcohol component and the carboxylic acid component, and is preferably 10 parts by mass or less, more preferably 8 parts by mass or less, even more preferably 5 parts by mass or less.

[0045] The method may include a step of steaming a reaction mixture containing the modified polyester resin (B) after obtaining the modified polyester resin (B). By steaming the reaction mixture, the unreacted amine compound contained in the condensate can be efficiently removed. The steaming may be carried out by introducing water vapor into the reaction system, or by generating water vapor in the reaction system by dripping ion-exchanged water into the reaction system. From the viewpoint of ease of operation, it is preferable to generate water vapor in the reaction system by dripping ion-exchanged water into the reaction system. In order to efficiently separate the amine compound from the reaction mixture, the supply amount of water vapor or ion-exchanged water is preferably 1 part by mass or more and 10 parts by mass or less with respect to 100 parts by mass of the total amount of the modified polyester resin (B).

[0046] [Physical properties of modified polyester resin (B)] The glass transition temperature of the modified polyester resin (B) is preferably 40° C. or higher, more preferably 45° C. or higher, and even more preferably 50° C. or higher, and from the viewpoint of further improving low-temperature fixability, is preferably 80° C. or lower, more preferably 75° C. or lower, and even more preferably 70° C. or lower. The softening point of the modified polyester resin (B) is preferably 90°C or higher, more preferably 95°C or higher, and even more preferably 100°C or higher, and from the viewpoint of further improving low-temperature fixability, it is preferably 140°C or lower, more preferably 130°C or lower, and even more preferably 120°C or lower.

[0047] The glass transition temperature and softening point of the modified polyester resin (B) can be appropriately adjusted by the type and amount of raw material monomers used, as well as production conditions such as reaction temperature, reaction time, and cooling rate, and these values ​​can be determined by the method described in the examples. When two or more modified polyester resins (B) are used in combination, the glass transition temperature and softening point of the mixture are preferably within the above-mentioned ranges.

[0048] In the binder resin composition for positively charged toner, the content of the modified polyester resin (B) is, from the viewpoint of increasing the positive chargeability and improving the fine line reproducibility, preferably 20% by mass or more, more preferably 25% by mass or more, even more preferably 30% by mass or more, and is preferably 60% by mass or less, more preferably 55% by mass or less, even more preferably 50% by mass or less.

[0049] In the binder resin composition for positively charged toner, the mass ratio of the modified polyester resin (B) to the composite resin (A) (modified polyester resin (B) / composite resin (A)) is, from the viewpoint of improving the positive chargeability of the binder resin composition for positively charged toner, preferably 0.3 or more, more preferably 0.5 or more, even more preferably 0.7 or more, and is preferably 2 or less, more preferably 1.5 or less, even more preferably 1 or less.

[0050] The binder resin composition for positively charged toner of the present invention may contain a resin other than the composite resin (A) and the modified polyester resin (B). Examples of such resins include amorphous polyester resins and crystalline polyester resins. From the viewpoint of improving the low-temperature fixing property of the toner, the binder resin composition for positively charged toner of the present invention preferably contains a crystalline polyester resin (C).

[0051] <Crystalline polyester resin (C)> The crystalline polyester resin (C) is, for example, a crystalline polyester resin which is a polycondensation product of an alcohol component and a carboxylic acid component. The alcohol component is preferably an α,ω-aliphatic diol. The α,ω-aliphatic diol has preferably 2 or more, more preferably 4 or more, even more preferably 6 or more, and preferably 16 or less, more preferably 14 or less, even more preferably 12 or less. Examples of α,ω-aliphatic diols include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, 1,13-tridecanediol, and 1,14-tetradecanediol. Among these, 1,4-butanediol, 1,6-hexanediol, 1,8-octanediol, 1,10-decanediol, and 1,12-dodecanediol are preferred, and 1,6-hexanediol is more preferred.

[0052] The amount of the α,ω-aliphatic diol in the alcohol component is preferably 80 mol % or more, more preferably 90 mol % or more, even more preferably 95 mol % or more, and is 100 mol % or less, even more preferably 100 mol %.

[0053] The alcohol component may contain other alcohol components different from the α,ω-aliphatic diol. Examples of the other alcohol components include aliphatic diols other than α,ω-aliphatic diols, such as 1,2-propanediol and neopentyl glycol; aromatic diols, such as alkylene oxide adducts of bisphenol A; and trihydric or higher alcohols, such as glycerin, pentaerythritol, and trimethylolpropane. These alcohol components may be used alone or in combination.

[0054] The carboxylic acid component is preferably an aliphatic dicarboxylic acid, more preferably a straight-chain aliphatic dicarboxylic acid. The aliphatic dicarboxylic acid preferably has 4 or more carbon atoms and preferably has 14 or less, more preferably 12 or less carbon atoms. Examples of the aliphatic dicarboxylic acid include fumaric acid, sebacic acid, dodecanedioic acid, and tetradecanedioic acid. Among these, fumaric acid, sebacic acid, and tetradecanedioic acid are preferred, and fumaric acid is more preferred. These carboxylic acid components may be used alone or in combination.

[0055] The amount of the aliphatic dicarboxylic acid in the carboxylic acid component is preferably 80 mol % or more, more preferably 90 mol % or more, even more preferably 95 mol % or more, and is 100 mol % or less, even more preferably 100 mol %.

[0056] The carboxylic acid component may contain other carboxylic acid components different from the aliphatic dicarboxylic acid. Examples of other carboxylic acid components include aromatic dicarboxylic acids such as terephthalic acid and isophthalic acid, and polyvalent carboxylic acids having three or more carboxylic acids. These carboxylic acid components may be used alone or in combination.

[0057] The equivalent ratio of the carboxyl groups of the carboxylic acid component to the hydroxyl groups of the alcohol component [COOH groups / OH groups] is preferably 0.7 or more, more preferably 0.8 or more, and is preferably 1.3 or less, more preferably 1.2 or less.

[0058] The crystalline polyester resin (C) may be produced, for example, by a process of polycondensing an alcohol component and a carboxylic acid component. The step of polycondensing the alcohol component and the carboxylic acid component is the same as step A described in the production method of the composite resin (A), and the preferred ranges are also the same.

[0059] [Physical properties of crystalline polyester resin (C)] The softening point of the crystalline polyester resin (C) is preferably 80°C or higher, more preferably 90°C or higher, and even more preferably 100°C or higher from the viewpoint of the storage stability of the toner, and is preferably 140°C or lower, more preferably 130°C or lower, and even more preferably 120°C or lower from the viewpoint of further improving the low-temperature fixing ability. The melting point of the crystalline polyester resin (C) is preferably 85°C or higher, more preferably 95°C or higher, and even more preferably 105°C or higher from the viewpoint of the storage stability of the toner, and is preferably 145°C or lower, more preferably 135°C or lower, and even more preferably 125°C or lower from the viewpoint of further improving the low-temperature fixing ability.

[0060] The softening point and melting point of the crystalline polyester resin (C) can be appropriately adjusted by the type and amount of raw material monomers, as well as production conditions such as reaction temperature, reaction time, cooling rate, etc., and are determined by the method described in the Examples below. When two or more crystalline polyester resins (C) are used in combination, it is preferable that the softening point and melting point values ​​obtained as a mixture of them are each within the above ranges.

[0061] The content of the crystalline polyester resin (C) in the binder resin composition is preferably 3 mass% or more, more preferably 5 mass% or more, even more preferably 8 mass% or more, and preferably 20 mass% or less, more preferably 18 mass% or less, even more preferably 15 mass% or less.

[0062] [Electrophotographic toner] The toner for electrophotography of the present invention (hereinafter also referred to as "the toner of the present invention") contains the binder resin composition for a positively charged toner, and preferably contains a colorant and the binder resin composition for a positively charged toner. The toner of the present invention contains, for example, toner base particles and an external additive. From the viewpoint of increasing the positive chargeability of the toner and improving fine line reproducibility, the content of the binder resin composition for positively charged toner in the toner base particles is preferably 60% by mass or more, more preferably 65% ​​by mass or more, even more preferably 70% by mass or more, and is preferably 97% by mass or less, more preferably 90% by mass or less, even more preferably 85% by mass or less.

[0063] [Coloring Agent] In the present invention, the toner base particles preferably contain a colorant. As the colorant, any of the dyes, pigments, etc. used as toner colorants can be used. Examples of colorants include carbon black, phthalocyanine blue (e.g., pigment blue 15:3), permanent brown FG, brilliant fast scarlet, pigment green B, rhodamine-B base, solvent red 49, solvent red 146, solvent blue 35, quinacridone, carmine 6B, and disazo yellow. The toner may be either a black toner or a color toner other than black. The content of the colorant in the toner base particles is preferably 1% by mass or more, more preferably 3% by mass or more, and preferably 10% by mass or less, more preferably 8% by mass or less.

[0064] [Release Agent] In the present invention, the toner base particles preferably contain a release agent. Examples of the release agent include polypropylene wax, polyethylene wax, polypropylene-polyethylene copolymer wax, hydrocarbon waxes such as microcrystalline wax, paraffin wax, 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.

[0065] The melting point of the release agent is preferably 60° C. or higher, more preferably 70° C. or higher, and preferably 160° C. or lower, more preferably 140° C. or lower, even more preferably 120° C. or lower, and even more preferably 100° C. or lower. The content of the release agent in the toner base particles is preferably 1% by mass or more, more preferably 2% by mass or more, even more preferably 3% by mass or more, and preferably 10% by mass or less, more preferably 7% by mass or less, even more preferably 5% by mass or less.

[0066] [Charge control agent] The toner of the present invention may contain a charge control agent. The charge control agent may be either a positively chargeable charge control agent or a negatively chargeable charge control agent. Among these, a positively chargeable charge control agent is preferred. Examples of the positively charged charge control agent include nigrosine dyes such as "Nigrosine Base EX", "Oil Black BS", "Oil Black SO", "Bontron (registered trademark) N-01", "Bontron (registered trademark) N-04", "Bontron (registered trademark) N-07", "Bontron (registered trademark) N-09", and "Bontron (registered trademark) N-11" (all manufactured by Orient Chemical Industry Co., Ltd.); triphenylmethane dyes containing a tertiary amine as a side chain, quaternary ammonium salt compounds such as "Bontron (registered trademark) P-51" (manufactured by Orient Chemical Industry 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 Chemical Industry Co., Ltd.); and styrene-acrylic resins, such as "FCA-701PT" and "FCA-201-PS" (manufactured by Fujikura Chemical Industry Co., Ltd.).

[0067] Examples of the negatively chargeable charge control agent include metal-containing azo dyes such as "Varifast (registered trademark) Black 3804", "Bontron (registered trademark) S-31", "Bontron (registered trademark) S-32", "Bontron (registered trademark) S-34", "Bontron (registered trademark) S-36" (all manufactured by Orient Chemical Industry Co., Ltd.), "Aizen Spiron Black TRH", "T-77" (manufactured by Hodogaya Chemical Industry Co., Ltd.), etc.; 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 (registered trademark) E-81", "Bontron (registered trademark) E-84", "Bontron (registered trademark) E-88", "Bontron (registered trademark) E-304" (all manufactured by Orient Chemical Industry Co., Ltd.), "TN-105" (manufactured by Hodogaya Chemical Industry Co., Ltd.), etc.; copper phthalocyanine dyes; and quaternary ammonium salts such as "COPY CHARGE PX VP434" (Clariant), nitroimidazole derivatives, etc.; organometallic compounds, etc. These charge control agents may be used alone or in combination of two or more kinds.

[0068] The content of the charge control agent in the toner base particles is preferably 1% by mass or more, more preferably 5% by mass or more, even more preferably 8% by mass or more, and preferably 25% by mass or less, more preferably 20% by mass or less, even more preferably 15% by mass or less.

[0069] [Other additives] The toner base particles may further contain, as other additives, additives such as magnetic powder, a flowability improver, a conductivity adjuster, a reinforcing filler such as a fibrous substance, an antioxidant, an antiaging agent, and a cleaning property improver, as appropriate.

[0070] In the toner of the present invention, the content of the toner base particles is preferably 80% by mass or more, more preferably 90% by mass or more, even more preferably 95% by mass or more, and is 100% by mass or less, preferably 99% by mass or less.

[0071] The volume median particle size of the toner particles (D 50) is preferably 2 μm or more, more preferably 3 μm or more, even 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% calculated from the smallest particle size.

[0072] [External additives] The toner of the present invention may further contain an external additive in order to improve fluidity. Examples of the external additive include inorganic material particles such as silica, alumina, titania, zirconia, tin oxide, and zinc oxide, and organic particles such as resin particles such as melamine resin particles and polytetrafluoroethylene resin particles. These may be used alone or in combination. Among these external additives, silica is preferred, and hydrophobic silica treated with a hydrophobic treatment agent is more preferred.

[0073] Examples of hydrophobic treatment agents include hexamethyldisilazane (HMDS), dimethyldichlorosilane (DMDS), silicone oil, octyltriethoxysilane (OTES), and methyltriethoxysilane. Among these, hexamethyldisilazane is preferred.

[0074] When the toner base particles are surface-treated using an external additive, the content of the external additive in the toner of the present invention is, from the viewpoint of the chargeability and flowability of the toner, preferably 0.5 parts by mass or more, more preferably 0.8 parts by mass or more, even more preferably 1 part by mass or more, and preferably 10 parts by mass or less, more preferably 5 parts by mass or less, even more preferably 4 parts by mass or less, relative to 100 parts by mass of the toner base particles.

[0075] [Toner manufacturing method] 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 phase inversion method, a suspension polymerization method, an emulsion aggregation method, etc., but from the viewpoints of productivity and dispersibility of the colorant, a pulverized toner obtained by a melt kneading method is preferred. In the melt-kneading method, the binder resin composition for positively charged toner and, if necessary, a colorant, a release agent, and other property improvers are uniformly dispersed, and then the mixture is melt-kneaded, cooled, pulverized, and classified by a known method to obtain a volume median particle size (D 50 ) Toner having a particle size of 2 μm or more and 15 μm or less can be obtained.

[0076] The toner of the present invention is used for developing latent images formed in electrophotography, electrostatic recording, electrostatic printing, etc. The toner can be used as a one-component developer, or mixed with a carrier to form a two-component developer. EXAMPLES

[0077] 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 were measured by the following methods.

[0078] [measurement] [Resin softening point, crystallinity index, melting point, glass transition temperature] (1) Softening point Using a flow tester "CFT-500D" (Shimadzu Corporation), 1 g of sample was heated at a temperature increase rate of 6°C / min, while applying a load of 1.96 MPa with the plunger, and extruding the sample from a nozzle with a diameter of 1 mm and a length of 1 mm. The plunger descent amount of the flow tester was plotted against the temperature, and the temperature at which half of the sample flowed out was taken as the softening point.

[0079] (2) Crystallinity index Using a differential scanning calorimeter "Q100" (manufactured by TA Instruments Japan Co., Ltd.), 0.02 g of sample was weighed into an aluminum pan and cooled to 0°C at a rate of 10°C / min. The sample was then left to stand for 1 minute, after which it was heated to 180°C at a rate of 10°C / min and the calorific value was measured. The temperature of the peak with the largest peak area among the observed endothermic peaks was taken as the endothermic maximum peak temperature (1), and the crystallinity index was calculated by (softening point (°C)) / (endothermic maximum peak temperature (1) (°C)).

[0080] (3) Melting point and glass transition temperature Using a differential scanning calorimeter "Q100" (manufactured by TA Instruments Japan Co., Ltd.), 0.02 g of the sample was weighed into an aluminum pan, heated to 200°C, and cooled from that temperature to 0°C at a rate of 10°C / min. The sample was then heated at a rate of 10°C / min, and the calorific value was measured. Among the endothermic peaks observed, the temperature of the peak with the largest peak area was taken as the maximum endothermic peak temperature (2). In the case of a crystalline resin, this peak temperature was taken as the melting point. In the case of an amorphous resin, when a peak was observed, the temperature of the peak was taken as the glass transition temperature. When no peak was observed but a step was observed, the temperature at the intersection of the tangent showing the maximum slope of the curve at the step and an extension of the baseline on the low temperature side of the step was taken as the glass transition temperature.

[0081] [Volume median particle diameter of toner base particles D 50 〕 Volume median particle size D of toner base particles 50 was measured as follows: 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: 13.6) was dissolved in the electrolyte to obtain a dispersion liquid with a concentration of 5% by mass. Dispersion conditions: 10 mg of a toner measurement sample was added to 5 mL of the dispersion liquid, and dispersed for 1 minute using an ultrasonic disperser. Thereafter, 25 mL of electrolyte was added, and the mixture was further dispersed for 1 minute using an ultrasonic disperser to prepare a sample dispersion liquid. Measurement conditions: The sample dispersion is added to 100 mL of the electrolyte to adjust the concentration so that the particle size of 30,000 particles can be measured in 20 seconds. Then, 30,000 particles are measured and the volume median particle size D is calculated from the particle size distribution. 50 asked for.

[0082] [Resin manufacturing] Production example A1 (resin A-1) 3603.1g of polyoxypropylene (2.2) adduct of bisphenol A and 1433.9g of polyoxyethylene (2.2) adduct of bisphenol A were placed in a 10-liter four-neck flask equipped with a dehydration tube equipped with a nitrogen inlet tube, a stirrer, and a thermocouple, and the temperature was raised to 100°C, after which 1660.1g of terephthalic acid was added and the temperature was raised to 160°C. While maintaining the temperature at 160°C, a mixture of 1512.8g of styrene, 70.9g of acrylic acid, and 181.5g of dibutyl peroxide was added dropwise over 1 hour and reacted for 60 minutes. Then, 36.0g of di(2-ethylhexanoate)tin (II) was added, the temperature was raised to 235°C, and the reaction was carried out for 5 hours. Then, the pressure in the flask was reduced, and the reaction was carried out under reduced pressure at 8 kPa until the desired softening point was reached. Then, the mixture was cooled to 210°C, and 432.0g of trimellitic anhydride was added and the reaction was carried out for 1 hour. Thereafter, the pressure in the flask was reduced, and the reaction was continued under reduced pressure at 8 kPa until the desired softening point was reached, yielding Resin A-1 as a composite resin. The physical properties are shown in Table 1.

[0083] [Table 1]

[0084] Manufacturing example B1 (resin B-1) 3417.4 g of polyoxypropylene (2.2) adduct of bisphenol A and 1360.0 g of polyoxyethylene (2.2) adduct of bisphenol A were placed in a 10-liter four-neck flask equipped with a dehydration tube equipped with a nitrogen inlet tube, a stirrer, and a thermocouple, and the mixture was heated to 100°C, after which 1921.9 g of terephthalic acid and 34.3 g of tin (II) di(2-ethylhexanoate) were added, the mixture was heated to 235°C, and reacted at 235°C for 7 hours. Thereafter, the pressure in the flask was reduced, and the reaction was carried out under reduced pressure at 8 kPa until the desired softening point was reached. Thereafter, the mixture was cooled to 160°C, 131.6 g of 2-diethylaminoethanol (manufactured by Nippon Nyukazai Co., Ltd., trade name: Amino Alcohol 2A) was added, the mixture was heated to 160°C, and reacted for 1 hour. Thereafter, the mixture was heated stepwise to 210°C at 10°C / hr, and 160.7 g of trimellitic anhydride was added and reacted for 1 hour. Thereafter, the pressure in the flask was reduced, and the reaction was continued under reduced pressure at 8 kPa until the desired softening point was reached, thereby obtaining Resin B-1 as a modified polyester resin. The physical properties are shown in Table 2.

[0085] Production Example B2 and Comparative Production Example B1 (Resins B-2 and B-11) Resins B-2 and B-11 were obtained as modified polyester resins in the same manner as in Production Example B1, except that 2-diethylaminoethanol was changed to 2-dibutylaminoethanol (manufactured by Nippon Nyukazai Co., Ltd., product name: Amino Alcohol 2B) or 2-dimethylaminoethanol (manufactured by Nippon Nyukazai Co., Ltd., product name: Amino Alcohol 2Mabs) as shown in Table 2. The physical properties are shown in Table 2.

[0086] Manufacturing Example B3 (Resin B-3) Resin B-3 was obtained as a modified polyester resin in the same manner as in Production Example B1, except that the amounts of each component were changed as shown in Table 2. The physical properties are shown in Table 2.

[0087] [Table 2]

[0088] Production example C1 (resin C-1) 4538.5g of 1,6-hexanediol was placed in a 10-liter four-neck flask equipped with a dehydration tube equipped with a nitrogen inlet tube, a stirrer and a thermocouple, and the temperature was raised to 100°C. After that, 4461.5g of fumaric acid, 18.0g of di(2-ethylhexanoate)tin(II) and 4.5g of 4-tert-butylcatechol were added and the temperature was raised to 140°C. After reacting for 1 hour, the temperature was raised to 150°C and reacted for 1 hour. Then, the temperature was raised stepwise to 200°C at 10°C / hr, and the reaction was carried out under reduced pressure at 8.0kPa until the desired softening point was reached, to obtain Resin C-1 as a crystalline polyester resin. The physical properties are shown in Table 3.

[0089] [Table 3]

[0090] Manufacturing example D1 (resin D-1) 3417.4g of polyoxypropylene (2.2) adduct of bisphenol A and 1360.0g of polyoxyethylene (2.2) adduct of bisphenol A were placed in a 10-liter four-neck flask equipped with a dehydration tube equipped with a nitrogen inlet tube, a stirrer and a thermocouple, and the temperature was raised to 100°C, after which 1921.9g of terephthalic acid and 34.3g of di(2-ethylhexanoate)tin (II) were added, the temperature was raised to 235°C, and the reaction was carried out at 235°C for 7 hours. Thereafter, the pressure in the flask was reduced, and the reaction was carried out at reduced pressure until the desired softening point was reached at 8kPa. Thereafter, the mixture was cooled to 210°C, and 160.7g of trimellitic anhydride was added and the reaction was carried out for 1 hour. Thereafter, the pressure in the flask was reduced, and the reaction was carried out at reduced pressure until the desired softening point was reached at 8kPa, to obtain resin D-1 as an amorphous polyester resin. The physical properties are shown in Table 4.

[0091] Manufacturing example D2 (resin D-2) Resin D-2 was obtained as an amorphous polyester resin in the same manner as in Production Example D1, except that the blending amounts of each component were changed as shown in Table 4. The physical properties are shown in Table 4.

[0092] [Table 4]

[0093] [Toner manufacturing] Examples 1 to 3 and Comparative Examples 1 to 3 50 parts by mass of composite resin A-1 or amorphous polyester resin D-2 shown in Table 5, 40 parts by mass of modified polyester resins B-1 to B-3 or B-11, or amorphous polyester resin D-1, 10 parts by mass of resin C-1 as a crystalline polyester resin, 8 parts by mass of colorant "Regal 330R" (carbon black manufactured by CABOT Co., Ltd.), 5 parts by mass of release agent "HNP-9" (paraffin wax (melting point 75 ° C.) manufactured by Nippon Seiro Co., Ltd.), and 15 parts by mass of positively charged charge control agent "FCA-201-PS" (manufactured by Fujikura Kasei Co., Ltd.) were stirred for 3 minutes at a rotation speed of 1500 r / min (circumferential speed 21.6 m / sec) using a Henschel mixer, and then the mixture was mixed with a co-rotating twin-screw extruder (manufactured by Ikegai Co., Ltd., product name: PCM-30, shaft diameter 2.9 cm, shaft cross-sectional area 7.06 cm 2 The roll rotation speed was 200 r / min (circumferential speed 0.30 m / sec), the barrel temperature was set to 100° C., and the feed rate of the kneaded material was 10 kg / h.

[0094] The kneaded product thus obtained was rolled and cooled with a cooling roll, and then coarsely pulverized to about 1 mm using a hammer mill. The coarsely pulverized product thus obtained was finely pulverized and classified using an air jet mill (manufactured by Nippon Pneumatic Co., Ltd., product name: IDS) to obtain a volume median particle size (D 50 ) toner base particles of 7.0 μm were obtained. 100 parts by mass of the obtained toner base particles and 0.5 parts by mass of hydrophobic silica "TG-820F" (manufactured by Cabot Specialty Chemicals, Inc., number average particle size: 8 nm) as external additives, 2.0 parts by mass of hydrophobic silica "NA-50Y" (manufactured by Nippon Aerosil Co., Ltd., number average particle size: 30 nm), and 0.4 parts by mass of polytetrafluoroethylene fine particles "KTL-500F" (manufactured by Kitamura Co., Ltd., number average particle size: 500 nm) were mixed in a Henschel mixer (manufactured by Mitsui Mining Co., Ltd.) at 2100 r / min (circumferential speed: 29 m / sec) for 3 minutes to obtain a toner.

[0095] [Toner Evaluation] [Electrostatic property] Under high temperature and humidity conditions of 32°C and 85%, 0.6g of the toner obtained above and 19.4g of silicone ferrite carrier (Kanto Denka Kogyo Co., Ltd., average particle size 90μm) were placed in a 50ml polyethylene container and mixed using a ball mill at 250r / min. The charge amount of the toner was measured using a Q / M meter (EPPING Co., Ltd.) by the following method. After a predetermined mixing time, a specified amount of the toner and carrier mixture was placed in a cell attached to the Q / M meter, and only the toner was sucked through a sieve (stainless steel, twill weave, wire diameter: 0.0035mm) with a mesh size of 32μm for 90 seconds. The voltage change on the carrier that occurred at that time was monitored, and the value of [total amount of electricity after 90 seconds (μC) / amount of sucked toner (g)] was taken as the charge amount (μC / g). The results are shown in Table 5.

[0096] [Fine line reproducibility] The toner obtained above was mounted on a non-magnetic one-component developing device (Brother Industries, Ltd., product name: HL-2040), and a horizontal line (line width 122 μm) pattern was printed in an environment of 25°C and relative humidity 50%. The reproducibility of the 1-dot line was confirmed with a digital microscope (Olympus Corporation, product name: DSX510, using a 50x lens, observation conditions: 693x), and the fine line reproducibility was evaluated according to the following criteria A to D. Image quality is excellent if it is criterion B or higher. The results are shown in Table 5. A: There are 5 or fewer breaks in horizontal lines (1 line / cm). B: There are 6 to 12 discontinuities in the horizontal line (1 line / cm). C: There are 13 to 20 discontinuities in the horizontal line (1 line / cm). D: There are 21 or more discontinuities in the horizontal line (1 line / cm).

[0097] [Table 5]

[0098] From the results of the Examples and Comparative Examples, it was found that the toner using the binder resin composition for a positively chargeable toner of the present invention has excellent positive chargeability and excellent fine line reproducibility. On the other hand, the toner of Comparative Example 1 using modified polyester resin B-11 had low positive chargeability and poor fine line reproducibility because the introduced amine compound had a lower electron donating alkyl group than the amine compound introduced into the resin used in the Examples. Also, the toner of Comparative Example 2 using amorphous polyester resin D-2 instead of composite resin (A) and the toner of Comparative Example 3 using amorphous polyester resin D-1 instead of modified polyester resin (B) both had low positive chargeability and poor fine line reproducibility. From these findings, it can be seen that by combining the modified polyester resin (B) in which a specific amine compound has been introduced at the end of an amorphous polyester resin having an acid group with the composite resin (A), the positive chargeability of the binder resin composition for a positively chargeable toner can be increased, and the fine line reproducibility of the toner using the same can be improved.

Claims

1. a composite resin (A) including a polyester resin segment which is a polycondensate of an alcohol component and a carboxylic acid component, and a vinyl resin segment which is an addition polymerization product of a raw material monomer including a styrene compound; A binder resin composition for a positively charged toner, comprising a modified polyester resin (B) which is a condensate of an amorphous polyester resin having an acid group and an amine compound, The binder resin composition for positively charged toners, wherein the amine compound is at least one selected from the group consisting of 2-diethylaminoethanol and 2-dibutylaminoethanol.

2. 2. The binder resin composition for a positively charged toner according to claim 1, wherein the modified polyester resin (B) contains 0.5% by mass or more and 10% by mass or less of a structural unit derived from an amine compound.

3. 3. The binder resin composition for a positively charged toner according to claim 1, wherein the composite resin (A) contains the vinyl resin segment in an amount of 5% by mass or more and 45% by mass or less.

4. The binder resin composition for a positively chargeable toner according to claim 1 or 2, further comprising a crystalline polyester resin.

5. 3. The binder resin composition for a positively charged toner according to claim 1, wherein a mass ratio of the modified polyester resin (B) to the composite resin (A) (modified polyester resin (B) / composite resin (A)) is 0.3 or more and 2 or less.

6. 3. An electrophotographic toner comprising the binder resin composition for a positively chargeable toner according to claim 1.