JP7463210B2 - Toner Binder - Google Patents

Description

The present invention relates to a toner binder.

In recent years, with the development of electrophotographic systems, the demand for electrophotographic devices such as copying machines and laser printers has increased rapidly, and the requirements for toner to meet these performance requirements are also becoming more sophisticated. In addition, the requirements for toner binders, which are the main component of toner, are also becoming more sophisticated.

Conventionally, for full-color electrophotography, a method or device has been known in which a latent image based on color image information is formed on a latent image carrier such as an electrophotographic photoreceptor, the latent image is developed with a toner of the corresponding color, and then the toner image is transferred onto a transfer material. After repeating the image formation process, the toner image on the transfer material is heated and fixed to obtain a multicolor image. To pass through these processes without any problems, the toner must first maintain a stable charge, and then must have good fixability to paper.

Furthermore, in order to promote miniaturization, speedup, and image quality improvement of electrophotographic apparatuses, as well as to save energy by reducing the energy consumed in the fixing process, there is a strong demand for improving the low-temperature fixability of toner.
Recently, many kinds of paper are used as transfer materials, such as recycled paper with large surface irregularities and coated paper with smooth surfaces. To accommodate the surface properties of these transfer materials, a fixing device with a wide nip width, such as a soft roller or belt roller, is preferably used. However, when the nip width is widened, the contact area between the toner and the fixing roller increases, and the so-called high-temperature offset phenomenon, in which the molten toner adheres to the fixing roller, is easily generated, so hot offset resistance is required.

The toner binder has a significant impact on the toner characteristics described above. Known toner binders include polystyrene resin, styrene-acrylic resin, polyester resin, epoxy resin, polyurethane resin, and polyamide resin. Recently, however, polyester resin has been attracting particular attention because it is easy to balance charge retention and fixability.

As a method for further improving the balance between charge retention rate and fixability, a toner binder has been proposed in which a long-chain alkyl acrylate is polymerized to reduce the melt viscosity and a polyester resin containing an unsaturated carboxylic acid as a constituent component is combined (Patent Documents 1 and 2). However, with this method, the organic solvent generated during crosslinking of the unsaturated carboxylic acid remains, causing odors to adhere to the toner binder, resulting in odors during printing, and the charge retention rate is insufficient under high temperature and high humidity conditions.
Furthermore, when such a styrene-acrylic resin and a polyester resin are used in combination, a sea-island structure is formed in the toner binder, and if the dispersibility of the structure is poor, the toner performance such as fixability and durability is deteriorated.

As mentioned above, there has not been an excellent toner binder that satisfies all of the requirements for charge retention rate (especially charge retention rate under high temperature and high humidity conditions), dispersibility, and odor.

International Publication No. 2018/110593 International Publication No. 2019/073731

The present invention aims to provide a toner binder that has excellent charge retention (especially under high temperature and humidity conditions), dispersibility, and odor.

The present inventors conducted extensive research to solve these problems and arrived at the present invention.
That is, the present invention provides a toner binder containing a polyester resin (A) and a crystalline vinyl resin (B), the polyester resin (A) being a reaction product of a polyester resin (A1) and an epoxy compound (E), and further satisfying the following relational formula (1):
|SP _A1 -SP _B |≦1.0 (1)
[wherein SP _A1 represents the solubility parameter (SP value) of the polyester resin (A1), and SP _B represents the SP value of the crystalline vinyl resin (B).]

The present invention makes it possible to provide a toner binder that has excellent charge retention (particularly under high temperature and humidity conditions), dispersibility, and odor.

The toner binder of the present invention is a toner binder containing a polyester resin (A) and a crystalline vinyl resin (B), and the polyester resin (A) is a reaction product of a polyester resin (A1) and an epoxy compound (E).
In the present invention, "crystalline" refers to a state in which a differential scanning calorimetry (DSC) curve has a maximum and an endothermic peak during the temperature rise process of the differential scanning calorimetry curve obtained by DSC measurement, whereas "amorphous" refers to a state in which the DSC curve does not have an endothermic peak.

The polyester resin (A) of the present invention is a reaction product of a polyester resin (A1) and an epoxy compound (E). The polyester resin (A1) is a polyester resin obtained by polycondensation of a polyol component (x) and a polycarboxylic acid component (y), and the composition of the resin is not particularly limited as long as it satisfies the above-mentioned relational formula (1).
The polyester resin (A1) may be a single type alone or a combination of two or more types.

The polyester resin (A1) is a resin obtained by polycondensation of a polyol component (x) and a polycarboxylic acid component (y).

The polyol component (x) of the polyester resin (A1) includes a diol (x1) and a trihydric or higher polyol (x2). These may be used alone or in combination of two or more.

Diols (x1) include alkylene glycols having 2 to 36 carbon atoms (ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, neopentyl glycol, 3-methyl-1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, 1,12-dodecanediol, etc.), alkylene ether glycols having 4 to 36 carbon atoms (diethylene glycol, triethylene glycol, etc.), Examples of suitable alkyl ethers include glycol, dipropylene glycol, polyethylene glycol, polypropylene glycol, and polytetramethylene ether glycol), alicyclic diols having 6 to 36 carbon atoms (1,4-cyclohexanedimethanol and hydrogenated bisphenol A), (poly)alkylene oxide adducts of the above alicyclic diols (preferably 1 to 30 average molar additions), aromatic diols [monocyclic dihydric phenols (e.g., hydroquinone, etc.) and bisphenols, etc.], and alkylene oxide adducts of the above aromatic diols (2 to 30 average molar additions).

The alkylene oxide adducts of the above bisphenols are obtained by adding alkylene oxide (hereinafter, "alkylene oxide" may be abbreviated as AO) to bisphenols.

The bisphenols include those represented by the following general formula (1).
HO-Ar-P-Ar-OH (1)
[In the formula, P represents an alkylene group having 1 to 3 carbon atoms, -SO ₂ -, -O-, -S- or a direct bond, and Ar represents a phenylene group in which a hydrogen atom may be substituted with a halogen atom or an alkyl group having 1 to 30 carbon atoms.]

Specific examples of bisphenols include bisphenol A, bisphenol F, bisphenol B, bisphenol AD, bisphenol S, trichlorobisphenol A, tetrachlorobisphenol A, dibromobisphenol F, 2-methylbisphenol A, 2,6-dimethylbisphenol A, and 2,2'-diethylbisphenol F, and two or more of these can be used in combination.

Examples of alkylene oxides added to bisphenols include alkylene oxides having 2 to 30 carbon atoms, such as ethylene oxide (hereinafter, "ethylene oxide" may be abbreviated as EO), propylene oxide (hereinafter, "propylene oxide" may be abbreviated as PO), butylene oxide, tetrahydrofuran, and combinations of two or more of these.

Examples of trivalent or higher polyols (x2) include aliphatic polyhydric alcohols having 3 to 36 carbon atoms and a valence of 3 or higher, sugars and derivatives thereof, AO adducts of aliphatic polyhydric alcohols (average number of moles added: 1 to 30), AO adducts of trisphenols (trisphenol PA, etc.) (average number of moles added: 2 to 30), and AO adducts of novolak resins (including phenol novolak and cresol novolak, etc., with an average degree of polymerization of 3 to 60) (average number of moles added: 2 to 30).

Examples of the aliphatic polyhydric alcohol having 3 to 36 carbon atoms and a valence of three or more include alkane polyols and their intramolecular or intermolecular dehydration products, such as glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, sorbitol, sorbitan, polyglycerin, and dipentaerythritol.
Furthermore, examples of sugars and their derivatives include sucrose and methyl glucoside.

Of these polyol components (x), from the viewpoint of dispersibility, diol (x1) is preferred, alkylene oxide adducts of aromatic diols are more preferred, alkylene oxide adducts of bisphenols (average number of moles added is preferably 2 to 5) are even more preferred, alkylene oxide adducts of bisphenol A (average number of moles added is preferably 2 to 5) are particularly preferred, and PO adducts of bisphenol A (average number of moles added is preferably 2 to 3) are most preferred.

The diol (x1) in the polyol component (x) of the polyester resin (A1) is preferably 80 to 100 mol %. When the diol (x1) is used in combination with a trihydric or higher polyol (x2), the molar ratio of the diol (x1) to the trihydric or higher polyol (x2) [(x1)/(x2)] is preferably 80/20 to 99/1, more preferably 85/15 to 98/2, from the viewpoint of charge retention rate (particularly charge retention rate under high temperature and high humidity conditions).

In addition to the polyol component (x), the alcohol component of the polyester resin (A1) may contain a mono-ol component, if necessary. Examples of mono-ols include linear or branched alkyl alcohols having 1 to 30 carbon atoms (methanol, ethanol, isopropanol, 1-decanol, dodecyl alcohol, myristyl alcohol, cetyl alcohol, stearyl alcohol, arachidyl alcohol, behenyl alcohol, and lignoceryl alcohol).

The polycarboxylic acid component (y) of the polyester resin (A1) may be a dicarboxylic acid (y1) or a trivalent or higher polycarboxylic acid (y2). These may be used alone or in combination of two or more.

Examples of dicarboxylic acids (y1) include aromatic dicarboxylic acids having 8 to 36 carbon atoms (phthalic acid, isophthalic acid, terephthalic acid, naphthalenedicarboxylic acid, etc.), aliphatic dicarboxylic acids having 2 to 50 carbon atoms (oxalic acid, malonic acid, succinic acid, adipic acid, leuparic acid, sebacic acid, etc.), alicyclic dicarboxylic acids having 6 to 40 carbon atoms (dimer acid (dimerized linoleic acid), etc.), alkene dicarboxylic acids having 4 to 36 carbon atoms (alkenyl succinic acids such as dodecenyl succinic acid, maleic acid, fumaric acid, citraconic acid, mesaconic acid, etc.), and ester-forming derivatives thereof. Here, the ester-forming derivatives refer to carboxylic acid anhydrides, alkyl (methyl, ethyl, butyl, stearyl, etc. having 1 to 24 carbon atoms, preferably those having 1 to 4 carbon atoms) esters, and partial alkyl esters.

Examples of trivalent or higher polycarboxylic acids (y2) include trivalent or higher aromatic polycarboxylic acids having 9 to 20 carbon atoms (such as trimellitic acid and pyromellitic acid), aliphatic (including alicyclic) tricarboxylic acids having 6 to 36 carbon atoms (such as hexanetricarboxylic acid and decanetricarboxylic acid), and ester-forming derivatives thereof.

Of these polycarboxylic acid components (y), from the viewpoint of charge retention rate (particularly charge retention rate at high temperature and high humidity), aromatic dicarboxylic acids having 8 to 36 carbon atoms, aliphatic dicarboxylic acids having 2 to 50 carbon atoms, and aromatic polycarboxylic acids having 9 to 20 carbon atoms are preferred, with terephthalic acid, isophthalic acid, adipic acid, succinic acid, maleic acid, fumaric acid, trimellitic acid, and pyromellitic acid being more preferred, and terephthalic acid, isophthalic acid, adipic acid, and trimellitic acid being even more preferred. In addition, anhydrides or lower alkyl esters of these acids may also be used.

The dicarboxylic acid (y1) in the polycarboxylic acid component (y) of the polyester resin (A1) is preferably 80 to 100 mol %. When the dicarboxylic acid (y1) is used in combination with a trivalent or higher polycarboxylic acid (y2), the molar ratio [(y1)/(y2)] of the dicarboxylic acid (y1) to the trivalent or higher polycarboxylic acid (y2) is preferably 80/20 to 99/1, more preferably 85/15 to 98/2, from the viewpoint of charge retention rate (particularly charge retention rate under high temperature and high humidity conditions).

In addition to the polycarboxylic acid component (y), the carboxylic acid component of the polyester resin (A1) may contain a monocarboxylic acid component, if necessary. Examples of the monocarboxylic acid include aromatic monocarboxylic acids having 7 to 37 carbon atoms (benzoic acid, toluic acid, 4-ethylbenzoic acid, 4-propylbenzoic acid, etc.), and aliphatic (including alicyclic) monocarboxylic acids having 2 to 50 carbon atoms (acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, pelargonic acid, capric acid, lauric acid, myristic acid, palmitic acid, margaric acid, stearic acid, behenic acid, etc.).

The polyester resin (A1) of the present invention can be produced in the same manner as known polyester resin production methods. For example, it can be produced by polycondensation reaction of the polyol component (x) and the polycarboxylic acid component (y) in an inert gas (nitrogen gas, etc.) atmosphere at a reaction temperature of preferably 150 to 280°C, more preferably 160 to 250°C, and even more preferably 170 to 235°C. The reaction time is preferably 30 minutes or more, more preferably 2 to 40 hours, from the viewpoint of ensuring that the polycondensation reaction is carried out. It is also effective to reduce the pressure in order to improve the reaction rate at the end of the reaction.

In this case, an esterification catalyst can be used as necessary.
Examples of the esterification catalyst include tin-containing catalysts (e.g., dibutyltin oxide, etc.), antimony trioxide, titanium-containing catalysts [e.g., titanium alkoxide, potassium oxalate titanate, titanium terephthalate, titanium alkoxide terephthalate, catalysts described in JP-A-2006-243715 {titanium diisopropoxybis(triethanolaminate), titanium dihydroxybis(triethanolaminate), titanium monohydroxytris(triethanolaminate), titanyl bis(triethanolaminate) and intramolecular polycondensates thereof, etc.} and catalysts described in JP-A-2007-11307 (titanium tributoxyterephthalate, titanium triisopropoxyterephthalate, titanium diisopropoxyditerephthalate, etc.)], zirconium-containing catalysts (e.g., zirconyl acetate, etc.), and zinc acetate. Among these, titanium-containing catalysts are preferred.

A stabilizer may be added to facilitate stable polymerization of the polyester. Examples of stabilizers include hydroquinone, methylhydroquinone, 4-tert-butylcatechol, 4-methoxyphenol, 2-tert-butyl-4-methoxyphenol, 2,6-di-tert-butyl-4-methoxyphenol, and hindered phenol compounds.

The weight ratio of the polyol component (x) and the polycarboxylic acid component (y) used in the polycondensation reaction is preferably 1/2 to 2/1, more preferably 1/1.5 to 1.5/1, and even more preferably 1/1.3 to 1.3/1, in terms of the equivalent ratio of hydroxyl groups to carboxyl groups ([OH]/[COOH]). The above hydroxyl groups are hydroxyl groups derived from the polyol component (x), and the carboxyl groups are the sum of the carboxyl groups derived from the polycarboxylic acid component (y).

There is no particular restriction on whether the polyester resin (A1) is crystalline or not, but from the viewpoint of charge retention rate (particularly charge retention rate under high temperature and high humidity), it is preferable that the polyester resin is amorphous. The amorphous polyester resin can be obtained by increasing the content of branched monomers, for example, monomers such as alkylene oxide adducts of bisphenols, in the polyol component (x) and polycarboxylic acid component (y) used.

The polyester resin (A1) may be any of a linear polyester resin, a crosslinked polyester resin, or a mixture of a linear polyester resin and a crosslinked polyester resin, but from the viewpoint of charge retention, it is preferably a crosslinked polyester resin or a mixture of a linear polyester resin and a crosslinked polyester resin, and more preferably a crosslinked polyester resin. The crosslinked polyester resin can be produced by using a trivalent or higher polyol (x2) and/or a trivalent or higher polycarboxylic acid (y2) as the polyol component (x) and the polycarboxylic acid component (y) of the polyester resin (A1).

The glass transition temperature (Tg _A1 ) of the polyester resin (A1) is preferably −35 to 60° C., more preferably −15 to 58° C., particularly preferably 15 to 55° C., and most preferably 35 to 55° C., from the viewpoints of dispersibility and charge retention rate (particularly charge retention rate under high temperature and high humidity).
The Tg is measured by using a DSC according to the method (DSC method) specified in ASTM D3418-82.

The peak top molecular weight (hereinafter, may be abbreviated as Mp) of the polyester resin (A1) is preferably from 2,000 to 200,000, more preferably from 2,500 to 100,000, particularly preferably from 3,000 to 60,000, and most preferably from 5,000 to 30,000, from the viewpoints of dispersibility and charge retention rate (particularly charge retention rate under high temperature and high humidity conditions).
The Mp of (A1) is measured by GPC under the following conditions.

First, a calibration curve is prepared by gel permeation chromatography (GPC) using standard polystyrene samples.
Next, the sample is separated by GPC, and the count number of the separated sample at each retention time is measured.
Next, a molecular weight distribution chart of the sample is prepared from the logarithmic values of the calibration curve and the obtained counts. The maximum value of the peak in the molecular weight distribution chart is the peak top molecular weight Mp.
When there are multiple peaks in the molecular weight distribution chart, the maximum value among the peaks is taken as the peak top molecular weight (Mp). The measurement conditions for the GPC measurement are as follows:

In the present invention, the peak top molecular weight Mp, number average molecular weight (hereinafter sometimes abbreviated as Mn), and weight average molecular weight (hereinafter sometimes abbreviated as Mw) of the polyester resin (A1) can be measured using GPC under the following conditions.
Equipment (example): Tosoh Corporation HLC-8120
Column (example): 2 TSK GEL GMH6 columns [manufactured by Tosoh Corporation]
Measurement temperature: 40°C
Sample solution: 0.25 wt% THF solution Solution injection amount: 100 μL
Detector: Refractive index detector Reference material: 12 standard polystyrenes (TSKstandard POLYSTYRENE) manufactured by Tosoh Corporation (molecular weight: 500, 1,050, 2,800, 5,970, 9,100, 18,100, 37,900, 96,400, 190,000, 355,000, 1,090,000, 2,890,000)
For measuring the molecular weight, a sample is dissolved in tetrahydrofuran (THF) to a concentration of 0.25% by weight, and the insoluble matter is filtered off using a glass filter to obtain a sample solution.
It should be noted that for the crystalline vinyl resin (B) and the toner binder described below, Mp, Mn and Mw can be determined in the same manner as above.

The acid value of the polyester resin (A1) is preferably from 5 to 50 mgKOH/g, more preferably from 8 to 48 mgKOH/g, and particularly preferably from 14 to 48 mgKOH/g, from the viewpoints of dispersibility and charge retention rate (particularly charge retention rate under high temperature and high humidity conditions).
The acid value can be measured by the method specified in JIS K0070.

The polyester resin (A) of the present invention is a reaction product of a polyester resin (A1) and an epoxy compound (E).

The epoxy compound (E) is not particularly limited as long as it has an epoxy group in the molecule, but from the viewpoint of charge retention rate (particularly charge retention rate under high temperature and high humidity conditions), a polyfunctional epoxy compound having two or more epoxy groups in the molecule is preferred. Examples of polyfunctional epoxy compounds include aromatic polyepoxy compounds, heterocyclic polyepoxy compounds, alicyclic polyepoxy compounds, and aliphatic polyepoxy compounds. The epoxy compound (E) may be used alone or in combination of two or more types.

Aromatic polyepoxy compounds include glycidyl ethers of polyhydric phenols, glycidyl esters of polycarboxylic acids, glycidyl aromatic polyamines, and other aromatic polyepoxy compounds.

Glycidyl ethers of polyhydric phenols include bisphenol F diglycidyl ether, bisphenol A diglycidyl ether, bisphenol B diglycidyl ether, bisphenol AD diglycidyl ether, bisphenol S diglycidyl ether, halogenated bisphenol A diglycidyl ether, tetrachloro bisphenol A diglycidyl ether, catechin diglycidyl ether, resorcinol diglycidyl ether, hydroquinone diglycidyl ether, pyrogallol triglycidyl ether, 1,5-dihydroxynaphthalene diglycidyl ether, dihydroxybiphenyl diglycidyl ether, octachloro-4,4'-dihydroxybiphenyl diglycidyl ether, tetramethylbiphenyl diglycidyl ether, dihydroxynaphthyl cresol triglycidyl ether, tris(hydroxyphenyl)methane triglycidyl ether, dinaphthyltriol triglycidyl ether, tetrakis(4-hydroxyphenyl)ethane tetraglycidyl ether, ether, p-glycidylphenyldimethyltriyl bisphenol A glycidyl ether, trismethyl-t-butyl-butylhydroxymethane triglycidyl ether, 9,9'-bis(4-hydroxyphenyl)fluoroenyl glycidyl ether, 4,4'-oxybis(1,4-phenylethyl)tetracresol glycidyl ether, 4,4'-oxybis(1,4-phenylethyl)phenyl glycidyl ether, bis(dihydroxynaphthalene)tetraglycidyl ether, novolac type epoxy resins (phenol novolac type epoxy resins, cresol novolac type epoxy resins, bisphenol A novolac type epoxy resins, limonene phenol novolac type epoxy resins, etc.), bisphenol A type epoxy resins, polyglycidyl ethers of polyphenols obtained by the condensation reaction of phenol with glyoxal, glutaraldehyde or formaldehyde, and polyglycidyl ethers of polyphenols obtained by the condensation reaction of resorcinol with acetone, etc.

Examples of glycidyl esters of polycarboxylic acids include diglycidyl phthalate, diglycidyl isophthalate, and diglycidyl terephthalate.

Examples of glycidyl aromatic polyamines include N,N-diglycidyl aniline, N,N,N',N'-tetraglycidyl xylylenediamine, and N,N,N',N'-tetraglycidyl diphenylmethanediamine.

Other aromatic polyepoxy compounds include triglycidyl ethers of p-aminophenol, diglycidyl urethane compounds obtained by the addition reaction of tolylene diisocyanate or diphenylmethane diisocyanate with glycidol, glycidyl group-containing polyurethane (pre)polymers obtained by reacting the above two reactants with polyols, and diglycidyl ethers of AO adducts of bisphenol A.

An example of a heterocyclic polyepoxy compound is trisglycidylmelamine.

Examples of alicyclic polyepoxy compounds include vinylcyclohexene dioxide, limonene dioxide, dicyclopentadiene dioxide, bis(2,3-epoxycyclopentyl)ether, ethylene glycol bisepoxydicyclopentyl ether, 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexanecarboxylate, 3,4-epoxy-6-methylcyclohexylmethyl-3',4'-epoxy-6'-methylcyclohexanecarboxylate, bis(3,4-epoxy-6-methylcyclohexylmethyl)adipate, bis(3,4-epoxy-6-methylcyclohexylmethyl)butylamine, 1,2-epoxy-4-(2-oxiranyl)cyclohexane adduct of 2,2-bis(hydroxymethyl)-1-butanol, and dimer acid diglycidyl ester. Examples of alicyclic polyepoxy compounds include the nuclear hydrogenated products of the aromatic polyepoxy compounds.

Examples of aliphatic polyepoxy compounds include polyglycidyl ethers of aliphatic polyhydric alcohols, polyglycidyl esters of aliphatic polycarboxylic acids, and glycidyl aliphatic amines.

Examples of polyglycidyl ethers of aliphatic polyhydric alcohols include ethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, tetramethylene glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, polyethylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, polytetramethylene glycol diglycidyl ether, neopentyl glycol diglycidyl ether, trimethylolpropane polyglycidyl ether, glycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, sorbitol polyglycidyl ether, and polyglycerol polyglycidyl ether.

Examples of polyglycidyl esters of aliphatic polycarboxylic acids include diglycidyl oxalate, diglycidyl malate, diglycidyl succinate, diglycidyl glutarate, diglycidyl adipate, and diglycidyl pimelate.

Examples of glycidyl aliphatic amines include N,N,N',N'-tetraglycidylhexamethylenediamine.
The aliphatic polyepoxy compounds also include (co)polymers of diglycidyl ether and glycidyl (meth)acrylate.

Among these polyfunctional epoxy compounds, from the viewpoint of dispersibility and charge retention rate (particularly charge retention rate at high temperature and high humidity), aromatic polyepoxy compounds, alicyclic polyepoxy compounds, and aliphatic polyepoxy compounds are preferred, aromatic polyepoxy compounds are more preferred, and novolac type epoxy resins and bisphenol A type epoxy resins are even more preferred. The above-mentioned epoxy compounds (E) may be used alone or in combination.

The epoxy compound (E) in the present invention is preferably a polyfunctional epoxy compound having an epoxy equivalent of 150 to 500 (g/eq, the same applies below), more preferably 160 to 300, and even more preferably 170 to 250. If the epoxy equivalent is 150 or more, the dispersibility is good, and if it is 500 or less, the charge retention rate (particularly the charge retention rate under high temperature and high humidity) is good.

The polyester resin (A) in the present invention can be obtained by mixing and reacting the polyester resin (A1) obtained by the above-mentioned production method with the epoxy compound (E). From the viewpoint of charge retention rate (particularly charge retention rate under high temperature and high humidity conditions) and odor, the polyester resin (A) is preferably a resin in which the polyester resin (A1) is crosslinked with the epoxy compound (E), and can be obtained by using the above-mentioned polyfunctional epoxy compound having an epoxy equivalent of 150 to 500 as the epoxy compound (E). The reaction is preferably carried out in an inert gas (nitrogen gas, etc.) atmosphere. In addition, the reaction temperature is preferably 120 to 220°C, more preferably 130 to 210°C, and even more preferably 140 to 200°C from the viewpoint of ensuring the reaction. The reaction time is preferably 2 minutes or more, more preferably 4 minutes or more, and even more preferably 5 to 30 minutes from the viewpoint of ensuring the reaction.

A known epoxy reaction catalyst (such as tertiary amines, imidazoles, and quaternary ammonium salts) can be added to the reaction between the polyester resin (A1) and the epoxy compound (E). In addition, a typical batch reactor or horizontal reactor (such as a plastic mill, kneader, or extruder) can be used as the reactor.

In addition, a suitable method for producing the polyester resin (A) in the present invention is to react the polyester resin (A1) with an epoxy compound (E) in the presence of the crystalline vinyl resin (B) described later. By reacting the polyester resin (A1) with the epoxy compound (E) in the presence of the crystalline vinyl resin (B), a toner binder excellent in dispersibility and charge retention rate (particularly charge retention rate under high temperature and high humidity conditions) can be obtained. Therefore, the present invention includes a toner binder obtained by reacting the polyester resin (A1) with the epoxy compound (E) in the presence of the crystalline vinyl resin (B) and a method for producing the same. The details of this production method will be described later.

The weight ratio of the epoxy compound (E) to the weight of the polyester resin (A1) is preferably 1 to 35% by weight, and more preferably 4 to 34% by weight, from the viewpoints of dispersibility and charge retention rate (particularly charge retention rate under high temperature and high humidity conditions).

In the present invention, the polyester resin (A) is a reaction product of the polyester resin (A1) and the epoxy compound (E), but it is sufficient that the reaction product of the polyester resin (A1) and the epoxy compound (E) is present in the toner binder, and the toner binder may contain some unreacted polyester resin (A1).

The toner binder of the present invention contains a crystalline vinyl resin (B).

The crystalline vinyl resin (B) is not particularly limited as long as it is a vinyl resin having crystallinity, but is preferably a polymer containing monomer (a) as an essential constituent monomer, and the monomer (a) is a (meth)acrylate having 21 to 40 carbon atoms and a chain hydrocarbon group. If the carbon number of monomer (a) is 21 or more, the crystallinity and charge retention rate (particularly the charge retention rate under high temperature and high humidity conditions) will be good, and if the carbon number is 40 or less, the dispersibility may be good.

Examples of the monomer (a) include (meth)acrylates having a linear alkyl group (having 18 to 36 carbon atoms) [octadecyl (meth)acrylate, nonadecyl (meth)acrylate, eicosyl (meth)acrylate, heneicosanyl (meth)acrylate, behenyl (meth)acrylate, lignoceryl (meth)acrylate, seryl (meth)acrylate, montanyl (meth)acrylate, triaconta (meth)acrylate, dotriaconta (meth)acrylate, and the like] and (meth)acrylates having a branched alkyl group (having 18 to 36 carbon atoms) [2-decyltetradecyl (meth)acrylate, and the like].
Of these, from the viewpoint of crystallinity, preferred are (meth)acrylates having a linear alkyl group (having 18 to 36 carbon atoms), more preferred are (meth)acrylates having a linear alkyl group (having 18 to 30 carbon atoms), even more preferred are octadecyl (meth)acrylate (stearyl (meth)acrylate), eicosyl (meth)acrylate, behenyl (meth)acrylate, lignoceryl (meth)acrylate, seryl (meth)acrylate and triaconta (meth)acrylate, particularly preferred are octadecyl acrylate, eicosyl acrylate, behenyl acrylate and lignoceryl acrylate, and most preferred is behenyl acrylate.
The monomer (a) may be used alone or in combination of two or more kinds.

In terms of dispersibility and charge retention rate (particularly charge retention rate under high temperature and high humidity conditions), the crystalline vinyl resin (B) may contain, as a constituent monomer, a monomer (b) having a vinyl group and a carbon number of 6 or less, in addition to the above-mentioned monomer (a).

Examples of the monomer (b) include (meth)acrylic monomers having 6 or less carbon atoms [(meth)acrylic acid, methyl (meth)acrylate, ethyl (meth)acrylate, 2-hydroxypropyl acrylate, 2-hydroxyethyl (meth)acrylate, ethyl-2-(hydroxymethyl)acrylate, etc.], vinyl ester monomers having 6 or less carbon atoms [vinyl acetate, vinyl propionate, isopropenyl acetate, etc.], aliphatic hydrocarbon-based vinyl monomers having 6 or less carbon atoms [ethylene, propylene, butene, butadiene, isoprene, 1,5-hexadiene, etc.], and monomers having 6 or less carbon atoms and having a nitrile group [(meth)acrylonitrile, etc.].
Of these, (meth)acrylic acid, methyl (meth)acrylate, 2-hydroxyethyl (meth)acrylate, vinyl acetate, and (meth)acrylonitrile are preferred.
The monomer (b) may be used alone or in combination of two or more kinds.

From the viewpoint of dispersibility and charge retention rate (particularly charge retention rate under high temperature and high humidity conditions), the crystalline vinyl resin (B) may contain a monomer (d) other than the above monomers (a) and (b) as a constituent monomer. As the monomer (d), preferred are those having, as a constituent monomer, a styrene-based monomer (d1), a (meth)acrylic monomer (d2) excluding monomer (a) among (meth)acrylic monomers having a carbon number of more than 6, a vinyl ester monomer (d3) having a carbon number of more than 6, and a monomer (d4) having an ethylenically unsaturated bond and at least one functional group selected from the group consisting of a nitrile group, a urethane group, a urea group, an amide group, an imide group, an allophanate group, and a biuret group.
The monomer (d) may be used alone or in combination of two or more kinds.

Examples of styrene-based monomers (d1) include styrene and alkylstyrenes having an alkyl group with 1 to 3 carbon atoms (e.g., α-methylstyrene and p-methylstyrene, etc.).

Examples of (meth)acrylic monomers (d2) include alkyl (meth)acrylates with an alkyl group having 4 to 17 carbon atoms [butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, etc.], hydroxyalkyl (meth)acrylates with an alkyl group having 4 to 17 carbon atoms, aminoalkyl group-containing (meth)acrylates with an alkyl group having 4 to 17 carbon atoms [dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, etc.], and esters of unsaturated carboxylic acids with 8 to 20 carbon atoms and polyhydric alcohols [ethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, 1,6-hexanediol di(meth)acrylate, polyethylene glycol di(meth)acrylate, etc.].

Examples of vinyl ester monomers (d3) include aliphatic vinyl esters having 7 to 15 carbon atoms and aromatic vinyl esters having 9 to 15 carbon atoms (e.g., methyl-4-vinylbenzoate, etc.).

Examples of monomers (d4) having more than 6 carbon atoms and having at least one functional group selected from the group consisting of a nitrile group, a urethane group, a urea group, an amide group, an imide group, an allophanate group, and a biuret group, and an ethylenically unsaturated bond include monomers (d41) having a urethane group, monomers (d42) having a urea group, monomers (d43) having an amide group, monomers (d44) having an imide group, monomers (d45) having an allophanate group, and monomers (d46) having a biuret group.

Examples of the monomer (d41) having a urethane group include a monomer obtained by reacting an alcohol having 2 to 22 carbon atoms (e.g., 2-hydroxyethyl methacrylate, vinyl alcohol, etc.) having an ethylenically unsaturated bond with an isocyanate having 1 to 30 carbon atoms by a known method, and a monomer obtained by reacting an alcohol having 1 to 26 carbon atoms with an isocyanate having 2 to 30 carbon atoms by a known method. Note that in this specification, the number of carbon atoms in a compound and structure having an isocyanate group does not include the number of carbon atoms contained in the isocyanate (NCO).
Examples of isocyanates having 1 to 30 carbon atoms include monoisocyanate compounds (benzenesulfonyl isocyanate, tosyl isocyanate, phenyl isocyanate, p-chlorophenyl isocyanate, butyl isocyanate, hexyl isocyanate, t-butyl isocyanate, cyclohexyl isocyanate, octyl isocyanate, 2-ethylhexyl isocyanate, dodecyl isocyanate, adamantyl isocyanate, 2,6-dimethylphenyl isocyanate, 3,5-dimethylphenyl isocyanate, and 2,6-dipropylphenyl isocyanate, etc.), aliphatic diisocyanate compounds (trimethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, pentamethylene diisocyanate, 1,2-propylene diisocyanate, 1,3-butylene diisocyanate, dodecamethylene diisocyanate, and 2,4,4-trimethylethylene diisocyanate, etc.), and diisocyanate, alicyclic diisocyanate compounds (1,3-cyclopentene diisocyanate, 1,3-cyclohexane diisocyanate, 1,4-cyclohexane diisocyanate, isophorone diisocyanate, hydrogenated diphenylmethane diisocyanate, hydrogenated xylylene diisocyanate, hydrogenated tolylene diisocyanate, hydrogenated tetramethylxylylene diisocyanate, etc.) and aromatic diisocyanate compounds (phenylene diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, 2,2'-diphenylmethane diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4'-toluidine diisocyanate, 4,4'-diphenyl ether diisocyanate, 4,4'-diphenyl diisocyanate, 1,5-naphthalene diisocyanate, xylylene diisocyanate, etc.).
Examples of alcohols having 1 to 26 carbon atoms include methanol, ethanol, propanol, isopropyl alcohol, butanol, t-butyl alcohol, pentanol, heptanol, octanol, 2-ethylhexanol, nonanol, decanol, undecyl alcohol, lauryl alcohol, dodecyl alcohol, myristyl alcohol, pentadecyl alcohol, cetanol, heptadecanol, stearyl alcohol, isostearyl alcohol, elaidyl alcohol, oleyl alcohol, linoleyl alcohol, linolenyl alcohol, nonadecyl alcohol, heneicosanol, behenyl alcohol, and erucyl alcohol.
Examples of the isocyanate having 2 to 30 carbon atoms and an ethylenically unsaturated bond include 2-isocyanatoethyl (meth)acrylate, 2-[0-(1'-methylpropylideneamino)carboxyamino]ethyl (meth)acrylate, 2-[(3,5-dimethylpyrazolyl)carbonylamino]ethyl (meth)acrylate, and 1,1-(bis(meth)acryloyloxymethyl)ethyl isocyanate.

Examples of monomers (d42) having a urea group include monomers obtained by reacting an amine having 3 to 22 carbon atoms (monovalent amines include, for example, primary amines (normal butylamine, t-butylamine, propylamine, isopropylamine, etc.), secondary amines (diethylamine, dinormal propylamine, dinormal butylamine, etc.), aniline, cyclohexylamine, etc.) with an isocyanate having 2 to 30 carbon atoms and an ethylenically unsaturated bond by a known method.

Examples of the monomer (d43) having an amide group include monomers obtained by reacting an amine having 1 to 30 carbon atoms with a carboxylic acid having 3 to 30 carbon atoms (such as acrylic acid and methacrylic acid) having an ethylenically unsaturated bond by a known method.

Examples of monomers having an imide group (d44) include monomers obtained by reacting ammonia with an ethylenically unsaturated bond-containing carboxylic acid anhydride having 4 to 10 carbon atoms (maleic anhydride, diacrylic anhydride, etc.) by a known method, and monomers obtained by reacting a primary amine having 1 to 30 carbon atoms with an ethylenically unsaturated bond-containing carboxylic acid anhydride having 4 to 10 carbon atoms by a known method.

Examples of the monomer (d45) having an allophanate group include a monomer obtained by reacting a monomer (d41) having a urethane group with an isocyanate having 1 to 30 carbon atoms by a known method.

Examples of the monomer (d46) having a buret group include a monomer obtained by reacting a monomer (d42) having a urea group with an isocyanate having 1 to 30 carbon atoms by a known method.

By using the monomer (d4), at least one functional group selected from the group consisting of a nitrile group, a urethane group, a urea group, an amide group, an imide group, an allophanate group, and a biuret group, preferably at least one functional group selected from the group consisting of a urethane group, a urea group, an amide group, an imide group, an allophanate group, and a biuret group, can be introduced into the crystalline vinyl resin (B).
As a method for introducing at least one functional group selected from the group consisting of a urethane group, a urea group, an amide group, an imide group, an allophanate group, and a biuret group into the crystalline vinyl resin (B), in addition to the method using the above-mentioned monomers (d41) to (d46), the following method can also be used.
First, of the two compounds (a compound having an ethylenically unsaturated bond and the other compound) for obtaining the monomers (d41) to (d46), the compound having an ethylenically unsaturated bond is reacted with the monomer (a). Then, the other compound is reacted with the polymer of the compound having an ethylenically unsaturated bond and the monomer (a). Through the above procedure, the "polymer of the compound having an ethylenically unsaturated bond and the monomer (a)" and the "other compound" are bonded to obtain the crystalline vinyl resin (B). During this reaction, the "polymer of the compound having an ethylenically unsaturated bond and the monomer (a)" and the "other compound" are bonded by a urethane group, a urea group, an amide group, an imide group, an allophanate group, or a biuret group, so that at least one functional group selected from the group consisting of a urethane group, a urea group, an amide group, an imide group, an allophanate group, and a biuret group can be introduced into the crystalline vinyl resin (B).

Among these monomers (d), preferred from the viewpoint of charge retention are styrene-based monomers (d1), (meth)acrylic monomers (d2) having more than 6 carbon atoms, excluding monomer (a), and monomers (d4) having more than 6 carbon atoms and at least one functional group selected from the group consisting of a nitrile group, a urethane group, a urea group, an amide group, an imide group, an allophanate group, and a biuret group, and having an ethylenically unsaturated bond. More preferred are styrene, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, a reaction product of 2-isocyanatoethyl (meth)acrylate with methanol, and a reaction product of 2-isocyanatoethyl (meth)acrylate with di-n-butylamine, even more preferred are styrene and butyl (meth)acrylate, and particularly preferred is styrene.

The weight ratio of monomer (a) in the monomers constituting crystalline vinyl resin (B) is preferably 30% by weight or more, more preferably 40% by weight or more, based on the total weight of the monomers constituting (B). When the weight ratio of monomer (a) is 30% by weight or more, the crystallinity and charge retention rate (particularly the charge retention rate under high temperature and high humidity) become good. In addition, from the viewpoint of dispersibility, the upper limit of the weight ratio of monomer (a) is preferably 99% by weight or less, more preferably 95% by weight or less, and even more preferably 80% by weight or less, based on the total weight of the monomers constituting (B). In one embodiment, it is preferably 30 to 99% by weight, more preferably 40 to 95% by weight, and even more preferably 40 to 80% by weight, based on the total weight of the monomers constituting (B).

From the viewpoint of charge retention rate (particularly charge retention rate under high temperature and high humidity conditions), the monomers constituting the crystalline vinyl resin (B) preferably contain monomer (b), and more preferably contain monomer (b) and monomer (d). The total weight ratio of monomer (b) and monomer (d) in the monomers constituting the crystalline vinyl resin (B) is preferably 1 to 70% by weight, more preferably 5 to 60% by weight, and even more preferably 20 to 60% by weight, based on the total weight of the monomers constituting (B).

The crystalline vinyl resin (B) can be produced by polymerizing a monomer composition containing the monomer (a) and, if necessary, the monomer (b) and the monomer (d) by a known method (such as the method described in JP-A-5-117330). For example, the crystalline vinyl resin (B) can be synthesized by a solution polymerization method in which the monomers are reacted with a radical reaction initiator (such as azobisisobutyronitrile) in a solvent (such as toluene).
The radical reaction initiator may be a known radical reaction initiator (c). The radical reaction initiator (c) is not particularly limited, and examples thereof include inorganic peroxides (c1), organic peroxides (c2), and azo compounds (c3). These radical reaction initiators may also be used in combination.

Inorganic peroxides (c1) are not particularly limited, but examples include hydrogen peroxide, ammonium persulfate, potassium persulfate, and sodium persulfate.

The organic peroxide (c2) is not particularly limited, but examples thereof include benzoyl peroxide, di-t-butyl peroxide, t-butylcumyl peroxide, dicumyl peroxide, α,α-bis(t-butylperoxy)diisopropylbenzene, 2,5-dimethyl-2,5-bis(t-butylperoxy)hexane, di-t-hexyl peroxide, 2,5-dimethyl-2,5-di-t-butylperoxyhexyne-3, acetyl peroxide, isobutyryl peroxide, octanyl peroxide, decanolyl peroxide, Examples include lauroyl peroxide, 3,3,5-trimethylhexanoyl peroxide, m-toluyl peroxide, t-butyl peroxy isobutyrate, t-butyl peroxy neodecanoate, cumyl peroxy neodecanoate, t-butyl peroxy 2-ethylhexanoate, t-butyl peroxy 3,5,5-trimethylhexanoate, t-butyl peroxy laurate, t-butyl peroxy benzoate, t-butyl peroxy isopropyl monocarbonate, and t-butyl peroxy acetate.

The azo compound (c3) is not particularly limited, but examples thereof include 2,2'-azobis-(2,4-dimethylvaleronitrile), 2,2'-azobis(2-methylbutyronitrile), 2,2'-azobisisobutyronitrile, 1,1'-azobis(cyclohexane-1-carbonitrile), 2,2'-azobis-4-methoxy-2,4-dimethylvaleronitrile, 2,2'-azobis(2-methylbutyronitrile), and azobisisobutyronitrile.

Among these, organic peroxides (c2) are preferred because they have high initiator efficiency and do not produce by-products such as cyanide compounds.

From the viewpoints of dispersibility and charge retention rate (particularly charge retention rate under high temperature and high humidity conditions), the endothermic peak top temperature (Tm _B ) of the crystalline vinyl resin (B) is preferably 40 to 100° C., more preferably 45 to 90° C. When the endothermic peak top temperature is 40° C. or higher, the charge retention rate (particularly charge retention rate under high temperature and high humidity conditions) becomes good, and when it is 100° C. or lower, the dispersibility becomes good.
Here, the endothermic peak top temperature (Tm _B ) of the crystalline vinyl resin (B) refers to the peak top temperature of the endothermic peak of the crystalline vinyl resin (B) in a second heating process in which the crystalline vinyl resin (B) is heated for the first time from 20° C. to 150° C. at 10° C./min using a differential scanning calorimeter (DSC), then cooled from 150° C. to 0° C. at 10° C./min, and subsequently heated from 0° C. to 150° C. at 10° C./min.

The endothermic peak top temperature (Tm _B ) is a value measured using a differential scanning calorimeter under the following conditions: As the differential scanning calorimeter, for example, DSC Q20 manufactured by TA Instruments Co., Ltd. can be used.
<Measurement conditions>
(1) Heat from 20° C. to 150° C. at 10° C./min. (2) Cool to 0° C. at 10° C./min. (3) Heat to 150° C. at 10° C./min. (4) Analyze each endothermic peak of the differential scanning calorimetry curve measured during the process of (3).

The number average molecular weight (Mn) of the crystalline vinyl resin (B) is preferably 1,000 to 300,000 from the viewpoints of dispersibility and charge retention rate (particularly charge retention rate under high temperature and high humidity conditions).

The weight average molecular weight (Mw) of the crystalline vinyl resin (B) is preferably from 1,000 to 300,000, and more preferably from 17,000 to 60,000, from the viewpoints of dispersibility and charge retention rate (particularly charge retention rate under high temperature and high humidity conditions).
The Mn and Mw of the crystalline vinyl resin (B) can be measured by the method described above.

The acid value of the crystalline vinyl resin (B) is preferably 60 mgKOH/g or less from the viewpoint of charge retention rate (particularly charge retention rate under high temperature and high humidity conditions).
The acid value of the crystalline vinyl resin (B) can be measured by the method specified in JIS K0070.

The toner binder of the present invention contains the above-mentioned polyester resin (A) and crystalline vinyl resin (B).

In the toner binder of the present invention, from the viewpoint of dispersibility and charge retention rate (particularly charge retention rate under high temperature and high humidity conditions), the content of polyester resin (A) in the toner binder is preferably 20 to 80% by weight, more preferably 20 to 75% by weight, and even more preferably 20 to 68% by weight, based on the weight of the toner binder. Also, the content of crystalline vinyl resin (B) in the toner binder is preferably 20 to 80% by weight, more preferably 25 to 80% by weight, and even more preferably 32 to 80% by weight, based on the weight of the toner binder.

The method for producing the toner binder is not particularly limited as long as the polyester resin (A) and the crystalline vinyl resin (B) are mixed uniformly. Known mixing methods include, for example, powder mixing, melt mixing, and solvent mixing. In addition, the polyester resin (A) and the crystalline vinyl resin (B) may be mixed together with other necessary toner raw materials at the same time when the toner is produced.

Examples of a mixer for powder mixing include a Henschel mixer, a Nauta mixer, and a Banbury mixer, with a Henschel mixer being preferred.
Examples of mixing devices for melt mixing include batch mixing devices such as reaction tanks and continuous mixing devices. Continuous mixing devices are preferred for uniform mixing in a short time at an appropriate temperature. Examples of continuous mixing devices include static mixers, extruders, continuous kneaders, and three-roll machines.
Examples of the solvent mixing method include a method in which the polyester resin (A) and the crystalline vinyl resin (B) are dissolved in a solvent (ethyl acetate, THF, acetone, etc.), homogenized, then the solvent is removed and pulverized, and a method in which the polyester resin (A) and the crystalline vinyl resin (B) are dissolved in a solvent (ethyl acetate, THF, acetone, etc.), dispersed in water, then granulated and the solvent is removed.

Furthermore, a further preferred method for producing the toner binder of the present invention includes a method in which, in the presence of the crystalline vinyl resin (B), the polyester resin (A1) and the epoxy compound (E) are crosslinked after or while being mixed, to obtain a toner binder containing the polyester resin (A) and the crystalline vinyl (B).
Specifically, there is a method in which a mixture of polyester resin (A1) and vinyl resin (B) is injected into a twin-screw extruder at a constant speed, and simultaneously, epoxy compound (E) is also injected at a constant speed, and the reaction is carried out while kneading and conveying at a temperature of 100 to 200° C. In this case, the polyester resin (A1) and vinyl resin (B), which are reaction raw materials charged or injected into the twin-screw extruder, may be directly injected into the extruder as they are without cooling the respective reacted resins from a molten state, or resins that have been produced once may be cooled and pulverized and then fed to the twin-screw extruder.
In addition, the method of melt mixing is not limited to these specifically exemplified methods, and it is needless to say that the melt mixing can be carried out in any suitable manner, such as, for example, a method in which the raw materials are charged into a reaction vessel, heated to a temperature at which they become molten, and mixed.

In addition, in the toner binder obtained by reacting polyester resin (A1) with epoxy compound (E) in the presence of crystalline vinyl resin (B), the weight ratio of polyester resin (A1) to crystalline vinyl resin (B) [(A1):(B)] is preferably 8:92 to 80:20, more preferably 10:90 to 70:30, and even more preferably 20:80 to 70:30, from the viewpoints of dispersibility and charge retention rate.

The toner binder of the present invention satisfies the following relational expression (1) from the viewpoints of dispersibility and charge retention rate.
|SP _A1 -SP _B |≦1.0 (1)
SP _A1 represents the solubility parameter (sometimes abbreviated as SP value) of the polyester resin (A1), and SP _B represents the SP value of the crystalline vinyl resin (B). |SP _A1 -SP _B | means the absolute value of the difference between SP _A1 and SP _B.
In the present invention, the SP value (cal/cm ³ ) ^0.5 is a value calculated by the method described in Polymer Engineering and Science, Vol. 14, pp. 151-154, by Robert F Fedors et al.
The relational expression (1) indicates the compatibility of the polyester resin (A1) and the crystalline vinyl resin (B), which are components of the polyester resin (A). If |SP _A1 -SP _B | is greater than 1.0, the dispersibility of the polyester resin (A) in the crystalline vinyl resin (B) may deteriorate, or the proportion of the polyester resin (A) on the toner surface may increase, leading to deterioration in heat resistance and thus deterioration in charge retention rate under high temperature and high humidity. For example, the above range can be easily achieved by making the PO adduct of bisphenol A (average number of moles added is preferably 2 to 3) in the polyol component (x) of the polyester resin (A1) 50% by weight or more, imparting an acid value to the polyester resin (A1), making the weight ratio of the (meth)acrylate having a chain hydrocarbon group and having 21 to 40 carbon atoms in the monomer constituting the crystalline vinyl resin (B) 30% by weight or more, and imparting an acid value to the crystalline vinyl resin (B).
From the viewpoint of dispersibility, it is preferable that |SP _A1 -SP _B |≦0.5 is satisfied.

From the viewpoints of dispersibility and charge retention rate (particularly charge retention rate under high temperature and high humidity conditions), the endothermic peak top temperature (Tm _C ) of the toner binder of the present invention is preferably 40 to 100° C., more preferably 45 to 90° C. When the endothermic peak top temperature is 40° C. or higher, the charge retention rate (particularly charge retention rate under high temperature and high humidity conditions) becomes good, and when it is 100° C. or lower, the dispersibility becomes good.
Here, the endothermic peak top temperature (Tm _C ) of the toner binder refers to the endothermic peak top temperature of the toner binder in a second heating process in which the toner binder is heated using a differential scanning calorimeter (DSC) for the first time from 20° C. to 150° C. at a rate of 10° C./min, then cooled from 150° C. to 0° C. at a rate of 10° C./min, and then heated from 0° C. to 150° C. at a rate of 10° C./min. The endothermic peak top temperature (Tm _C ) of the toner binder can be measured in the same manner as the endothermic peak top temperature (Tm _B ) of the crystalline vinyl resin (B) described above.
The endothermic peak top temperature (Tm) of the toner binder can be adjusted to the above-mentioned preferred range by adjusting the carbon number of the monomer (a) constituting the crystalline vinyl resin (B) or adjusting the weight ratio of the monomer (a) constituting the crystalline vinyl resin (B). In general, the endothermic peak top temperature (Tm) tends to increase by increasing the carbon number of the monomer (a), increasing the weight ratio of the monomer (a), or increasing the weight average molecular weight of the crystalline vinyl resin (B). In addition, when the content of the crystalline vinyl resin (B) is low, the endothermic peak top temperature (Tm) is less likely to decrease by increasing the difference in SP value between the polyester resin (A) and the crystalline vinyl resin (B).

The glass transition temperature (Tg _C ) of the toner binder is preferably −35 to 60° C., more preferably −15 to 58° C., particularly preferably 15 to 55° C., and most preferably 35 to 55° C., from the viewpoints of dispersibility and charge retention rate (particularly charge retention rate under high temperature and high humidity conditions).
The Tg can be determined by using a DSC according to the method specified in ASTM D3418-82 (DSC method). For example, a DSC Q20 manufactured by TA Instruments Co., Ltd. can be used to measure the glass transition temperature (Tg _C ). The glass transition temperature (Tg _C ) can be measured under the following conditions.
<Measurement conditions>
(1) Heat from 30°C to 150°C at 20°C/min. (2) Hold at 150°C for 10 minutes. (3) Cool to -35°C at 20°C/min. (4) Hold at -35°C for 10 minutes. (5) Heat to 150°C at 20°C/min. (6) The differential scanning calorimetry curve measured during (5) is analyzed.

The content of organic solvent in the toner binder of the present invention is preferably 2000 ppm or less based on the weight of the toner binder. If the organic solvent content is 2000 ppm or less, the odor is good. The content of organic solvent in the toner binder is more preferably 1500 ppm or less, even more preferably 1000 ppm or less, and particularly preferably 500 ppm or less.

Methods for controlling the organic solvent content include, for example, (1) controlling the amount of organic solvent used when producing the polyester resin (A), the crystalline vinyl resin (B), and the toner binder, (2) controlling the amount of initiator (controlling initiator decomposition products), and (3) controlling the organic solvent used in (1) and (2) and by desolvating the initiator decomposition residue.

In (3), the method for removing the organic solvent and the method for removing the initiator decomposition residue are not particularly limited, but include a method in which the pulverized toner binder is fed to a twin-screw extruder and reduced pressure is applied from a vent port while melting and conveying the toner binder. In this case, the amount of organic solvent in the toner binder can be controlled by adjusting the melting temperature, the number of shaft rotations, the degree of reduced pressure, etc. In addition, the toner binder can be desolvated by reducing the pressure at a desired temperature. In addition, the pressure can be reduced while stirring using a stirrer. In this case, the amount of organic solvent in the toner binder can be controlled by adjusting the temperature, the degree of reduced pressure, the stirring speed, etc. The temperature during desolvation is preferably 20 to 200°C, more preferably 30 to 170°C, and even more preferably 40 to 160°C. The degree of reduced pressure during desolvation is preferably 0.01 to 100 kPa, more preferably 0.1 to 95 kPa, and even more preferably 1 to 90 kPa.
On the other hand, the raw materials can be reacted in the twin-screw extruder while simultaneously reducing the pressure through a vent. When the raw materials are charged into a reaction vessel and reacted, the solvent can also be removed by reducing the pressure directly after the reaction. In this case, the amount of organic solvent in the toner binder can be controlled by adjusting the same items as above.
Alternatively, the amount of organic solvent in the toner binder can be controlled by crushing the toner binder and placing it in a dryer in which the temperature and pressure (normal pressure or reduced pressure) are adjusted according to the type of organic solvent to be removed.
The method of removing the solvent in a short time is preferred because it is less likely to cause an ester exchange reaction between the polyester resin (A) and the crystalline vinyl resin (B) and provides a good charge retention rate (particularly under high temperature and high humidity conditions).
The content (ppm) of the organic solvent can be measured, for example, by gas chromatography analysis or gas chromatography mass spectrometry under the following conditions.
The content of the organic solvent in the toner binder according to the examples and comparative examples was measured under the following conditions.

[Gas chromatographic analysis measurement conditions]
Gas chromatograph: Agilent 6890N
Mass spectrometer: Agilent 5973 inert
Column: ZB-WAX (liquid phase: (14%-cyanopropyl-phenyl)methylpolysiloxane) 0.25 mm x 30 m df = 1.0 μm
Column temperature: 70°C → 300°C (10°C/min)
Injection temperature: 200°C
Split ratio: 50:1
Injection volume: 1 μL
Helium flow rate: 1 mL/min Detector: MSD

The organic solvent contained in the toner binder is not particularly limited, and examples thereof include ethanol, normal propyl alcohol, isopropyl alcohol, n-butanol, s-butanol, t-butanol, diacetone alcohol, 2-ethylhexanol, acetone, methyl ethyl ketone, methyl isobutyl ketone, methyl n-butyl ketone, acetonitrile, dimethylacetamide, dimethylformamide, N-methylpyrrolidone, ethylene glycol, diethyl ether, diisopropyl ether, tetrahydrofuran, 1,4-dioxane, 1,3-dioxane, 1,3-oxolane, methyl cellosolve, ethyl cellosolve, butyl cellosolve, ethyl carbitol, butyl carbitol, propylene glycol monopropyl ether, and propylene glycol monobutyl. Ether, 1,2-dichloroethane, 1,2-dichloroethylene, 1,1,2,2-tetrachloroethane, trichloroethylene, tetrachloroethylene, hexane, pentane, benzene, heptane, toluene, xylene, cresol, chlorobenzene, styrene, isobutyl acetate, isopropyl acetate, isopentyl acetate, ethyl acetate, n-propyl acetate, n-butyl acetate, n-pentyl acetate, methyl acetate, cyclohexanol, cyclohexanone, methylcyclohexanol, methylcyclohexanone, dichloromethane, orthodichlorobenzene, dimethyl sulfoxide, acetic anhydride, acetic acid, hexamethylphosphoric triamide, triethylamine, pyridine, acetophenone, t-hexyl alcohol, t-amyl alcohol, and t-butoxybenzene.
Among these, from the viewpoint of odor, preferred are compounds having 2 to 10 carbon atoms, more preferred are compounds having 3 to 8 carbon atoms, and even more preferred are acetone, isopropyl alcohol and t-butanol.

Conventionally, the method of desolvation according to (3) above has been common for controlling the organic solvent content, but the melt of the crosslinked polyester resin has low fluidity, and desolvation takes a long time, resulting in a deterioration in the resin properties due to scission of the crosslinked structure, etc. In the present invention, the polyester resin (A1) is crosslinked with the epoxy compound (E), so compared to the conventional crosslinking reaction using the radical reaction initiator (c), the organic solvents and the like generated by the decomposition of the radical reaction initiator (c), which cause a decrease in thermal stability and odor generation, can be suppressed, and desolvation after the crosslinking reaction, which causes a decrease in resin properties, is not necessary, so that a toner with good heat resistance storage stability, charge retention rate (especially charge retention rate under high temperature and high humidity conditions), blocking properties, and odor can be obtained.

The toner binder of the present invention is useful when applied to a toner. The toner contains the toner binder of the present invention.

In addition to the toner binder of the present invention, the toner may contain, as necessary, one or more known additives selected from colorants, release agents, charge control agents, and flow agents.

As the colorant, all of the dyes and pigments used as toner colorants can be used. For example, carbon black, iron black, Sudan Black SM, Fast Yellow G, Benzidine Yellow, Pigment Yellow, India Fast Orange, Irgasin Red, Paranitroaniline Red, Toluidine Red, Carmine FB, Pigment Orange R, Lake Red 2G, Rhodamine FB, Rhodamine B Lake, Methyl Violet B Lake, Phthalocyanine Blue, Pigment Blue, Brilliant Green, Phthalocyanine Green, Oil Yellow GG, Kayaset YG, Orazol Brown B, and Oil Pink OP can be mentioned. The colorant may be any one of these alone, or may be a mixture of two or more. In addition, if necessary, magnetic powder (powder of ferromagnetic metals such as iron, cobalt, and nickel, or compounds such as magnetite, hematite, and ferrite) can be contained to function as a colorant.
The content of the colorant is preferably 1 to 40 parts by weight, more preferably 3 to 10 parts by weight, based on 100 parts by weight of the toner binder. When a magnetic powder is used, the content is preferably 20 to 150 parts by weight, more preferably 40 to 120 parts by weight, based on 100 parts by weight of the toner binder.

The release agent preferably has a flow softening point (T1/2) of 50 to 170°C as measured by a flow tester, and examples of such agents include aliphatic hydrocarbon waxes such as polyolefin wax, microcrystalline wax, paraffin wax, and Fischer-Tropsch wax, as well as oxides thereof, carnauba wax, montan wax, and deacidified waxes thereof, ester wax, fatty acid amides, fatty acids, higher alcohols, and fatty acid metal salts.

The flow softening point (T1/2) of the release agent is a value measured under the following conditions.
<Method for measuring flow softening point (T1/2)>
Using a constant test force extrusion type capillary rheometer flow tester [for example, CFT-500D, manufactured by Shimadzu Corporation], 1 g of a measurement sample is heated at a temperature increase rate of 6° C./min while applying a load of 1.96 MPa with a plunger and extruding the sample from a nozzle having a diameter of 1 mm and a length of 1 mm. A graph of "plunger depression amount (flow value)" versus "temperature" is then drawn, and the temperature corresponding to 1/2 of the maximum value of the plunger depression amount is read from the graph, and this value (the temperature at which half of the measurement sample has flowed out) is taken as the flow softening point (T1/2).

Examples of polyolefin waxes include (co)polymers of olefins (e.g., ethylene, propylene, 1-butene, isobutylene, 1-hexene, 1-dodecene, 1-octadecene, and mixtures thereof) (including those obtained by (co)polymerization and those obtained by further thermal degradation) (e.g., low molecular weight polypropylene, low molecular weight polyethylene, low molecular weight polypropylene-polyethylene copolymers), oxides of olefin (co)polymers with oxygen and/or ozone, maleic acid modified products of olefin (co)polymers (e.g., maleic acid and its derivatives (maleic anhydride, monomethyl maleate, monobutyl maleate, dimethyl maleate, etc.) modified products), copolymers of olefins and unsaturated carboxylic acids ((meth)acrylic acid, itaconic acid, maleic anhydride, etc.) and/or unsaturated carboxylic acid alkyl esters ((meth)acrylic acid alkyl esters (alkyl having 1 to 18 carbon atoms) and maleic acid alkyl esters (alkyl having 1 to 18 carbon atoms), etc.).

Examples of microcrystalline waxes include Hi-Mic-2095, Hi-Mic-1090, Hi-Mic-1080, Hi-Mic-1070, Hi-Mic-2065, Hi-Mic-1045, and Hi-Mic-2045 manufactured by Nippon Seiro Co., Ltd.

Examples of paraffin waxes include Paraffin WAX-155, Paraffin WAX-150, Paraffin WAX-145, Paraffin WAX-140, Paraffin WAX-135, HNP-3, HNP-5, HNP-9, HNP-10, HNP-11, HNP-12, and HNP-51 manufactured by Nippon Seiro Co., Ltd.

Examples of Fischer-Tropsch wax include Sasolwax C80 manufactured by Sasol.

Examples of carnauba wax include Refined Carnauba Wax Special No. 1 manufactured by Kato Yoko Co., Ltd.

Examples of ester waxes include fatty acid ester waxes (e.g., Nissan Electol WEP-2, WEP-3, WEP-4, WEP-5, and WEP-8 manufactured by NOF Corp.).

Examples of higher alcohols include aliphatic alcohols having 30 to 50 carbon atoms, such as triacontanol. Examples of fatty acids include fatty acids having 30 to 50 carbon atoms, such as triacontanol.

Examples of fatty acid amides include Diamid Y and Diamid 200 manufactured by Mitsubishi Chemical Corporation.

The charge control agent may be either a positively charged charge control agent or a negatively charged charge control agent, and examples of the charge control agent include nigrosine dyes, triphenylmethane dyes containing a tertiary amine as a side chain, quaternary ammonium salts, polyamine resins, imidazole derivatives, polymers containing quaternary ammonium bases, metal-containing azo dyes, copper phthalocyanine dyes, metal salts of salicylic acid, boron complexes of benzilic acid, polymers containing sulfonic acid groups, fluorine-containing polymers, and polymers containing halogen-substituted aromatic rings.

Examples of fluidizing agents include silica, titania, alumina, calcium carbonate, fatty acid metal salts, silicone resin particles, and fluororesin particles, and two or more of them may be used in combination. From the viewpoint of the chargeability of the toner, silica is preferred. From the viewpoint of the transferability of the toner, the silica is preferably hydrophobic.

The content of the toner binder in the toner is preferably from 30 to 97% by weight, more preferably from 40 to 95% by weight, and even more preferably from 45 to 92% by weight, based on the weight of the toner.
The content of the colorant is preferably 0.05 to 60% by weight, more preferably 0.1 to 55% by weight, and even more preferably 0.5 to 50% by weight, based on the weight of the toner.
The content of the releasing agent is preferably 0 to 30% by weight, more preferably 0.5 to 20% by weight, and further preferably 1 to 10% by weight, based on the weight of the toner.
The content of the charge control agent is preferably 0 to 20% by weight, more preferably 0.1 to 10% by weight, and even more preferably 0.5 to 7.5% by weight, based on the weight of the toner.
The content of the fluidizing agent is preferably 0 to 10% by weight, more preferably 0 to 5% by weight, and further preferably 0.1 to 4% by weight, based on the weight of the toner.
The total content of the additives is preferably 3 to 70% by weight, more preferably 4 to 58% by weight, and even more preferably 5 to 50% by weight, based on the weight of the toner.
By setting the composition ratio of the toner in the above range, it is possible to easily obtain a toner having good charge retention rate (particularly charge retention rate under high temperature and high humidity conditions) and dispersibility.

The toner may be obtained by any of the known methods such as a kneading and pulverizing method, an emulsion phase inversion method, and a polymerization method.
For example, when a toner is obtained by a kneading and pulverizing method, the components constituting the toner except for the fluidizing agent are dry-blended, melt-kneaded, coarsely pulverized, and finally, finely divided using a jet mill pulverizer or the like, and further classified to obtain fine particles having a volume average particle size (D50) of preferably 5 to 20 μm, and then the fluidizing agent is mixed therein to produce the toner.
The volume average particle size (D50) is measured using a Coulter counter (for example, trade name: Multisizer III [manufactured by Beckman Coulter, Inc.]).

When obtaining toner by the emulsion phase inversion method, the components constituting the toner, excluding the fluidizing agent, are dissolved or dispersed in an organic solvent, and then emulsified by adding water, etc., and then separated and classified to produce the toner. The volume average particle size of the toner is preferably 3 to 15 μm.

The toner is mixed with carrier particles such as iron powder, glass beads, nickel powder, ferrite, magnetite, and ferrite coated with resin (acrylic resin, silicone resin, etc.) as necessary, and used as a developer for an electric latent image. When carrier particles are used, the weight ratio of the toner to the carrier particles is preferably 1/99 to 99/1. Alternatively, the toner can be rubbed against a member such as a charging blade instead of the carrier particles to form an electric latent image.
The toner does not necessarily need to contain carrier particles.

The toner is fixed to a support (paper, polyester film, etc.) by a copier, printer, etc. to form a recording material. The method of fixing to the support can be a known hot roll fixing method or flash fixing method, etc.

The toner and toner binder of the present invention are used for developing electrostatic images or magnetic latent images in electrophotography, electrostatic recording, electrostatic printing, etc. More specifically, they are used for developing electrostatic images or magnetic latent images that are particularly suitable for full color.

The present invention will be further explained below with reference to examples and comparative examples, but the present invention is not limited to these. In the following, "parts" refers to parts by weight unless otherwise specified.

<Production Example 1> [Production of Polyester Resin (A1-1)]
In a reaction vessel equipped with a cooling tube, a stirrer and a nitrogen inlet tube, 700 parts of bisphenol A.PO 2 mole adduct, 101 parts of terephthalic acid, 53 parts of trimellitic anhydride, and 2.5 parts of titanium diisopropoxy bistriethanolamine as a condensation catalyst were placed, and the mixture was reacted for 2 hours under a nitrogen stream at 230 ° C. while distilling off the water produced. Next, the mixture was reacted for 5 hours under a reduced pressure of 0.5 to 2.5 kPa, and after confirming that the acid value was less than 1 mgKOH / g, the temperature was lowered to 180 ° C. 205 parts of adipic acid was added and reacted for 2 hours, and then reacted for 3 hours under a reduced pressure of 0.5 to 2.5 kPa, and after confirming that the acid value was 48 mgKOH / g, the mixture was taken out to obtain a polyester resin (A1-1).

<Production Example 2> [Production of Polyester Resin (A1-2)]
In a reaction vessel equipped with a cooling tube, a stirrer and a nitrogen inlet tube, 389 parts of bisphenol A PO 2 mole adduct, 174 parts of bisphenol A PO 3 mole adduct, 161 parts of bisphenol A EO 2 mole adduct, 154 parts of terephthalic acid, 34 parts of trimellitic anhydride, and 2.5 parts of titanium diisopropoxy bistriethanol aminate as a condensation catalyst were placed and reacted for 2 hours under a nitrogen stream at 230 ° C. while distilling off the water produced. Next, the mixture was reacted for 5 hours under a reduced pressure of 0.5 to 2.5 kPa, and after confirming that the acid value was less than 1 mg KOH / g, the temperature was lowered to 180 ° C. 165 parts of adipic acid was added and reacted for 2 hours, and then the mixture was reacted for 3 hours under a reduced pressure of 0.5 to 2.5 kPa, and after confirming that the acid value was 30 mg KOH / g, the mixture was taken out to obtain a polyester resin (A1-2).

<Production Example 3> [Production of Polyester Resin (A1-3)]
In a reaction vessel equipped with a cooling tube, a stirrer and a nitrogen inlet tube, 741 parts of bisphenol A-PO 3 mole adduct, 209 parts of terephthalic acid, 15 parts of trimellitic anhydride, and 2.5 parts of titanium diisopropoxy bistriethanolamine as a condensation catalyst were placed, and the mixture was reacted for 2 hours under a nitrogen stream at 230 ° C. while distilling off the water produced. Next, the mixture was reacted for 5 hours under a reduced pressure of 0.5 to 2.5 kPa, and after confirming that the acid value was less than 1 mg KOH / g, the temperature was lowered to 180 ° C. 38 parts of isophthalic acid and 67 parts of adipic acid were added and reacted for 2 hours, and then the mixture was reacted for 3 hours under a reduced pressure of 0.5 to 2.5 kPa, and after confirming that the acid value was 14 mg KOH / g, the mixture was taken out to obtain a polyester resin (A1-3).

<Production Example 4> [Production of Polyester Resin (A1-4)]
In a reaction vessel equipped with a cooling tube, a stirrer and a nitrogen inlet tube, 741 parts of bisphenol A·EO 2 mole adduct, 118 parts of terephthalic acid, 120 parts of adipic acid, 13 parts of trimethylolpropane, and 2.5 parts of titanium diisopropoxy bistriethanolamine as a condensation catalyst were placed, and reacted for 2 hours under a nitrogen stream at 230°C while distilling off the water produced. Next, the reaction was carried out for 5 hours under a reduced pressure of 0.5 to 2.5 kPa, and then the temperature was lowered to 180°C. 1 part of 2,6-di-tert-butyl-4-methylphenol was placed as a polymerization inhibitor, and 86 parts of fumaric acid were placed, and the reaction was carried out for 8 hours under a reduced pressure of 0.5 to 2.5 kPa, followed by removal to obtain polyester resin (A1-4).

The compositions and physical properties of polyester resins (A1-1) to (A1-4) are shown in Table 1.

<Production Example 5> [Production of Crystalline Vinyl Resin (B-1)]
138 parts of xylene was charged into the autoclave, and after replacing with nitrogen, the temperature was raised to 165°C in a sealed state with stirring. A mixed solution of 450 parts of behenyl acrylate [manufactured by NOF Corp., the same applies below], 150 parts of styrene [manufactured by Idemitsu Kosan Co., Ltd., the same applies below], 150 parts of acrylonitrile [manufactured by Nacalai Tesque Co., Ltd., the same applies below], 1.0 part of di-t-butyl peroxide [Perbutyl D, manufactured by NOF Corp., the same applies below], and 100 parts of xylene was adjusted to 60°C, and while controlling the temperature inside the autoclave to 165°C, it was dropped over 3 hours to carry out polymerization. After dropping, the dropping line was washed with 12 parts of xylene. The temperature was further maintained for 0.5 hours, and the reaction rate of monomer (a) was confirmed. Since the reaction rate of monomer (a) was less than 95%, 0.4 parts of di-t-butyl peroxide was further added and reacted until the reaction rate was 95% or more. The solvent was removed at 165° C. for 5 hours under a reduced pressure of 0.5 to 2.5 kPa to obtain a crystalline vinyl resin (B-1).

<Production Example 6> [Production of Crystalline Vinyl Resin (B-2)]
335 parts of behenyl acrylate and 363 parts of ethyl acetate [manufactured by Sankyo Chemical Co., Ltd., the same applies below] were charged into an autoclave, and after replacing with nitrogen, the temperature was raised to 78°C in a sealed state with stirring. A mixed solution of 50 parts of acrylonitrile, 79 parts of styrene, 15 parts of methyl acrylate [manufactured by Mitsubishi Chemical Co., Ltd., the same applies below], 21 parts of methacrylic acid [manufactured by Mitsubishi Chemical Co., Ltd., the same applies below], 10.0 parts of 2,2'-azobis(2-methylbutyronitrile) [manufactured by Fujifilm Wako Pure Chemical Co., Ltd., the same applies below], and 112 parts of ethyl acetate was dropped over 2 hours while controlling the temperature inside the autoclave to 78°C, to carry out polymerization. After dropping, the dropping line was washed with 25 parts of ethyl acetate. After maintaining the temperature at the same temperature for 5 hours, the temperature inside the autoclave was raised to 92°C over 1 hour. After maintaining the temperature at the same temperature for another 2 hours, the temperature was lowered to 60°C, and the reaction rate of monomer (a) was confirmed. Since the reaction rate of the monomer (a) was less than 95%, the temperature was raised to 80°C, and a mixed solution of 2.0 parts of 2,2'-azobis(2,4-dimethylvaleronitrile) [manufactured by Fujifilm Wako Pure Chemical Industries, Ltd., the same applies below] and 38 parts of ethyl acetate was added dropwise over 1 hour. After the dropwise addition, the mixture was kept at 80°C for 2 hours, and reacted until the reaction rate reached 95% or more. The solvent was removed at 110°C for 6 hours under reduced pressure of 0.5 to 2.5 kPa, to obtain a crystalline vinyl resin (B-2).

<Production Example 7> [Production of Crystalline Vinyl Resin (B-3)]
138 parts of xylene was charged into the autoclave, and after replacing with nitrogen, the temperature was raised to 165°C in a sealed state under stirring. A mixed solution of 600 parts of stearyl acrylate [manufactured by NOF Corp., the same applies below], 50 parts of styrene, 100 parts of acrylonitrile, 0.2 parts of di-t-butyl peroxide, and 100 parts of xylene was adjusted to 60°C, and while controlling the temperature inside the autoclave to 165°C, it was dropped over 3 hours to polymerize. After dropping, the dropping line was washed with 12 parts of xylene. The same temperature was maintained for another 0.5 hours to confirm the reaction rate of monomer (a). Since the reaction rate of monomer (a) was less than 95%, 0.1 parts of di-t-butyl peroxide was further added and reacted until the reaction rate was 95% or more. The solvent was removed at 165°C for 5 hours under reduced pressure of 0.5 to 2.5 kPa to obtain a crystalline vinyl resin (B-3).

<Production Example 8> [Production of Crystalline Vinyl Resin (B-4)]
200 parts of behenyl acrylate and 363 parts of ethyl acetate were charged into an autoclave, and the autoclave was replaced with nitrogen, and then heated to 78°C in a sealed state under stirring. A mixed solution of 67 parts of styrene, 35 parts of methyl acrylate, 150 parts of methacrylonitrile [manufactured by Asahi Kasei Corporation, the same applies below], 48 parts of methacrylic acid, 6.0 parts of 2,2'-azobis(2-methylbutyronitrile), and 112 parts of ethyl acetate was dropped over 2 hours while controlling the temperature inside the autoclave at 78°C to carry out polymerization. After dropping, the dropping line was washed with 25 parts of ethyl acetate. After maintaining the temperature at the same temperature for 5 hours, the temperature inside the autoclave was raised to 92°C over 1 hour. After maintaining the temperature at the same temperature for another 2 hours, the temperature was lowered to 60°C, and the reaction rate of monomer (a) was confirmed. Since the reaction rate of the monomer (a) was less than 95%, the temperature was raised to 80°C, and a mixed solution of 2.0 parts of 2,2'-azobis(2,4-dimethylvaleronitrile) and 38 parts of ethyl acetate was added dropwise over 1 hour. After the dropwise addition, the mixture was kept at 80°C for 2 hours, and reacted until the reaction rate reached 95% or more. The solvent was removed at 110°C for 6 hours under reduced pressure of 0.5 to 2.5 kPa, to obtain a crystalline vinyl resin (B-4).

<Production Example 9> [Production of Crystalline Vinyl Resin (B-5)]
250 parts of behenyl acrylate and 363 parts of ethyl acetate were charged into an autoclave, and the autoclave was replaced with nitrogen, and then heated to 78°C in a sealed state under stirring. A mixed solution of 100 parts of styrene, 50 parts of methyl acrylate, 70 parts of methacrylonitrile, 30 parts of acrylic acid [manufactured by Mitsubishi Chemical Corporation, the same applies below], 3.0 parts of 2,2'-azobis(2-methylbutyronitrile), and 112 parts of ethyl acetate was dropped over 2 hours while controlling the temperature inside the autoclave at 78°C to carry out polymerization. After dropping, the dropping line was washed with 25 parts of ethyl acetate. After maintaining the temperature at the same temperature for 5 hours, the temperature inside the autoclave was raised to 92°C over 1 hour. After maintaining the temperature at the same temperature for another 2 hours, the temperature was lowered to 60°C, and the reaction rate of monomer (a) was confirmed. Since the reaction rate of the monomer (a) was less than 95%, the temperature was raised to 80°C, and a mixed solution of 0.5 parts of 2,2'-azobis(2,4-dimethylvaleronitrile) and 38 parts of ethyl acetate was added dropwise over 1 hour. After the dropwise addition, the mixture was kept at 80°C for 2 hours, and reacted until the reaction rate reached 95% or more. The solvent was removed at 120°C for 6 hours under reduced pressure of 0.5 to 2.5 kPa, to obtain a crystalline vinyl resin (B-5).

<Production Example 10> [Production of Crystalline Vinyl Resin (B-6)]
138 parts of xylene was charged into the autoclave, and after replacing with nitrogen, the temperature was raised to 165°C in a sealed state with stirring. A mixed solution of 300 parts of behenyl acrylate, 150 parts of stearyl acrylate, 125 parts of acrylonitrile, 75 parts of butyl acrylate [manufactured by Mitsubishi Chemical Co., Ltd., the same applies below], 100 parts of methyl methacrylate [manufactured by Sumitomo Chemical Co., Ltd., the same applies below], 0.5 parts of di-t-butyl peroxide, and 100 parts of xylene was adjusted to 60°C, and while controlling the temperature inside the autoclave to 165°C, the mixture was dropped over 3 hours to carry out polymerization. After dropping, the dropping line was washed with 12 parts of xylene. The temperature was further maintained for 0.5 hours, and the reaction rate of monomer (a) was confirmed. Since the reaction rate of monomer (a) was less than 95%, 0.2 parts of di-t-butyl peroxide was further added and reacted until the reaction rate was 95% or more. The solvent was removed at 165° C. for 5 hours under a reduced pressure of 0.5 to 2.5 kPa to obtain a crystalline vinyl resin (B-6).

<Production Example 11> [Synthesis of triacontyl acrylate]
A reaction vessel equipped with a stirring device, a heating/cooling device, a thermometer, an air inlet tube, a pressure reducing device, and a water reducing device was charged with 50 parts of 1-triacontanol, 50 parts of toluene, 12 parts of acrylic acid, and 0.05 parts of hydroquinone, and stirred to homogenize. Then, 2 parts of paratoluenesulfonic acid was added, and after stirring for 30 minutes, the mixture was reacted for 5 hours while removing water generated at 100 ° C. while blowing air at a flow rate of 30 mL / min. Thereafter, the pressure in the reaction vessel was adjusted to 300 mmHg, and the reaction was continued for another 3 hours while removing water generated. After cooling the reaction solution to room temperature, 30 parts of a 10 wt% aqueous sodium hydroxide solution was added, and the mixture was stirred for 1 hour, and then allowed to stand to separate the organic phase and the aqueous phase. The organic phase was collected by liquid separation and centrifugation, and 0.01 parts of hydroquinone was added, and the solvent was removed under reduced pressure while blowing air, to obtain triacontyl acrylate.

<Production Example 12> [Production of Crystalline Vinyl Resin (B-7)]
138 parts of xylene was charged into the autoclave, and after replacing with nitrogen, the temperature was raised to 165°C in a sealed state under stirring. A mixed solution of 525 parts of triacontyl acrylate obtained in Production Example 11, 75 parts of styrene, 150 parts of acrylonitrile, 1.5 parts of di-t-butyl peroxide, and 100 parts of xylene was adjusted to 60°C, and while controlling the temperature inside the autoclave to 165°C, it was dropped over 3 hours to polymerize. After dropping, the dropping line was washed with 12 parts of xylene. The temperature was further maintained at the same temperature for 0.5 hours, and the reaction rate of monomer (a) was confirmed. Since the reaction rate of monomer (a) was less than 95%, 0.5 parts of di-t-butyl peroxide was further added and reacted until the reaction rate was 95% or more. The solvent was removed at 170°C for 5 hours under a reduced pressure of 0.5 to 2.5 kPa to obtain a crystalline vinyl resin (B-7).

The compositions and physical properties of crystalline vinyl resins (B-1) to (B-7) are shown in Table 2.

Example 1: Production of toner binder (C-1)
50 parts of polyester resin (A1-1), 50 parts of crystalline vinyl resin (B-1), 3.6 parts of jER157S70 [bisphenol A novolac type epoxy resin, manufactured by Mitsubishi Chemical Corporation, the same below, epoxy equivalent 209] (E-1) and 0.1 parts of imidazole [manufactured by Fujifilm Wako Pure Chemical Industries, the same below] as an epoxidation catalyst were mixed, fed to a twin-screw kneader [Kurimoto Iron Works, Ltd., S5KRC kneader] at 80 kg/hour, and kneaded and extruded at 180 ° C. and 90 rpm for 5 minutes to carry out a crosslinking reaction. The mixture obtained by mixing was cooled to obtain a toner binder (C-1) containing polyester resin (A), which is a reaction product of polyester resin (A1-1) and an epoxy compound.

Example 2: Production of toner binder (C-2)
40 parts of polyester resin (A1-2), 60 parts of crystalline vinyl resin (B-2), 6.3 parts of jER157S70 (E-1), and 0.1 parts of imidazole as an epoxidation catalyst were mixed and fed to a twin-screw kneader at 80 kg/hr, and kneaded and extruded at 180° C. and 90 rpm for 5 minutes to carry out a crosslinking reaction. The mixture was cooled to obtain a toner binder (C-2) containing polyester resin (A), which is a reaction product of polyester resin (A1-2) and an epoxy compound.

Example 3: Production of toner binder (C-3)
70 parts of polyester resin (A1-2), 30 parts of crystalline vinyl resin (B-3), 3.9 parts of EHPE3150 [1,2-epoxy-4-(2-oxiranyl)cyclohexane adduct of 2,2-bis(hydroxymethyl)-1-butanol, manufactured by Daicel Corporation, the same below, epoxy equivalent 175] (E-2) and 0.1 parts of imidazole as an epoxidation catalyst were mixed, fed to a twin-screw kneader at 80 kg/hour, and kneaded and extruded at 180° C. and 90 rpm for 5 minutes to carry out a crosslinking reaction. The mixture obtained by mixing was cooled to obtain a toner binder (C-3) containing polyester resin (A), which is a reaction product of polyester resin (A1-2) and an epoxy compound.

Example 4: Production of toner binder (C-4)
50 parts of polyester resin (A1-3), 50 parts of crystalline vinyl resin (B-4), 17.1 parts of jER1001 [bisphenol A type epoxy resin, manufactured by Mitsubishi Chemical Corporation, the same applies below, epoxy equivalent 470] (E-3) and 0.1 parts of imidazole as an epoxidation catalyst were mixed, fed to a twin-screw kneader at 80 kg/hour, and kneaded and extruded at 180° C. and 90 rpm for 5 minutes to carry out a crosslinking reaction. The mixture obtained by mixing was cooled to obtain a toner binder (C-4) containing polyester resin (A), which is a reaction product of polyester resin (A1-3) and an epoxy compound.

Example 5: Production of toner binder (C-5)
60 parts of polyester resin (A1-3), 40 parts of crystalline vinyl resin (B-5), 8.0 parts of pentaerythritol polyglycidyl ether (manufactured by Nagase ChemteX Corporation, the same applies below, epoxy equivalent 229) (E-4) and 0.1 parts of imidazole as an epoxidation catalyst were mixed, fed to a twin-screw kneader at 80 kg/hour, and kneaded and extruded at 180° C. and 90 rpm for 5 minutes to carry out a crosslinking reaction. The mixture obtained by mixing was cooled to obtain a toner binder (C-5) containing polyester resin (A), which is a reaction product of polyester resin (A1-3) and an epoxy compound.

Example 6: Production of toner binder (C-6)
20 parts of polyester resin (A1-1), 80 parts of crystalline vinyl resin (B-2), 4.7 parts of jER157S70 (E-1) and 0.1 parts of imidazole as an epoxidation catalyst were mixed and fed to a twin-screw kneader at 80 kg/hr, and kneaded and extruded at 160° C. and 90 rpm for 5 minutes to carry out a crosslinking reaction. The mixture obtained was cooled to obtain a toner binder (C-6) containing polyester resin (A) which is a reaction product of polyester resin (A1-1) and an epoxy compound.

Example 7: Production of toner binder (C-7)
30 parts of polyester resin (A1-2), 70 parts of crystalline vinyl resin (B-6), 3.0 parts of jER157S70 (E-1) and 0.1 parts of imidazole as an epoxidation catalyst were mixed and fed to a twin-screw kneader at 80 kg/hr, and kneaded and extruded at 160° C. and 90 rpm for 5 minutes to carry out a crosslinking reaction. The mixture was cooled to obtain a toner binder (C-7) containing polyester resin (A) which is a reaction product of polyester resin (A1-2) and an epoxy compound.

Example 8: Production of toner binder (C-8)
40 parts of polyester resin (A1-3), 60 parts of crystalline vinyl resin (B-7), 1.5 parts of jER828 [bisphenol A type epoxy resin, manufactured by Mitsubishi Chemical Corporation, the same applies below, epoxy equivalent 190] (E-5) and 0.1 parts of imidazole as an epoxidation catalyst were mixed, fed to a twin-screw kneader at 50 kg/hour, and kneaded and extruded at 150° C. and 90 rpm for 7 minutes to carry out a crosslinking reaction. The mixture obtained by mixing was cooled to obtain a toner binder (C-8) containing polyester resin (A), which is a reaction product of polyester resin (A1-3) and an epoxy compound.

Example 9: Production of toner binder (C-9)
70 parts of polyester resin (A1-2), 3.9 parts of EHPE3150 (E-2), and 0.1 parts of imidazole as an epoxidation catalyst were mixed and fed to a twin-screw kneader at 80 kg/hr, and kneaded and extruded at 180° C. and 90 rpm for 5 minutes to carry out a crosslinking reaction. The resulting resin and 30 parts of crystalline vinyl resin (B-3) were fed to a twin-screw kneader at 80 kg/hr, and kneaded and extruded at 180° C. and 90 rpm for 5 minutes, and the resulting mixture was cooled to obtain a toner binder (C-9) containing polyester resin (A), which is a reaction product of polyester resin (A1-2) and an epoxy compound.

Comparative Example 1 [Production of Toner Binder (C'-1)]
50 parts of polyester resin (A1-4), 50 parts of crystalline vinyl resin (B-3), 0.4 parts of jER157S70 (E-1), and 0.1 parts of imidazole as an epoxidation catalyst were mixed and fed to a twin-screw kneader at 80 kg/hr, and kneaded and extruded at 160° C. and 90 rpm for 5 minutes to carry out a crosslinking reaction. The mixture was cooled to obtain a toner binder (C'-1) containing polyester resin (A), which is a reaction product of polyester resin (A1-4) and an epoxy compound.

Comparative Example 2 [Production of Toner Binder (C'-2)]
40 parts of polyester resin (A1-4) and 60 parts of crystalline vinyl resin (B-1) were mixed and fed to a twin-screw kneader at 52 kg/hr, and simultaneously 1.0 part of t-butylperoxyisopropyl monocarbonate was fed as a radical reaction initiator (c) at 0.52 kg/hr, and the mixture was kneaded and extruded at 160° C. and 90 rpm for 7 minutes to carry out a crosslinking reaction, and further mixed while removing the organic solvent by reducing the pressure to 50 kPa from a vent port. The mixture obtained by mixing was cooled to obtain a toner binder (C'-2) containing a polyester resin in which polyester resin (A1-4) was crosslinked by a carbon-carbon bond.

The composition and physical properties of toner binders (C-1) to (C-9) and (C'-1) to (C'-2) are shown in Table 3.

<Toner Production>
To 88 parts of the toner binder [the toner binder obtained in each of the Examples and Comparative Examples], 7 parts of a pigment carbon black [MA-100, manufactured by Mitsubishi Chemical Corporation], 3 parts of a release agent carnauba wax, and 1 part of a charge control agent [T-77, manufactured by Hodogaya Chemical Co., Ltd.] were added, and a toner was prepared by the following method.
First, the mixture was premixed using a Henschel mixer [FM10B, manufactured by Nippon Coke & Engineering Co., Ltd.], and then kneaded using a twin-screw kneader [PCM-30, manufactured by Ikegai Corp.]. Then, the mixture was finely pulverized using a supersonic jet pulverizer, Labojet [KJ-25, manufactured by Kurimoto Iron Works Ltd.], and then classified using an elbow jet classifier [EJ-L-3 (LABO) type, manufactured by Matsubo Corp.] to obtain toner particles having a volume average particle size D50 of 7 μm.
Next, 100 parts of the toner particles were mixed with 1 part of colloidal silica (Aerosil R972, manufactured by Nippon Aerosil Co., Ltd.) as a fluidizing agent in a sample mill to obtain a toner.

Toners were produced using the toner binders obtained in each Example and Comparative Example with the blending amounts of raw materials shown in Table 4. In addition, in Table 4, the toners obtained using the toner binders (C-1) to (C-9) of Examples 1 to 9 are shown as (T-1) to (T-9), and the toners obtained using the toner binders (C'-1) and (C'-2) of Comparative Examples 1 and 2 are shown as (T'-1) and (T'-2), respectively.

[Toner Performance Evaluation]
The methods for evaluating the charge retention rate (under low temperature and low humidity conditions and high temperature and high humidity conditions), dispersibility and odor of the obtained toners (T-1) to (T-9), (T'-1) and (T'-2) will be described below, including the criteria for evaluation.

<Charge retention rate (low temperature and low humidity conditions and high temperature and high humidity conditions)>
(1) 1 g of toner and 0.01 g of Aerosil R8200 (manufactured by Evonik Japan Co., Ltd.) were mixed for 1 hour using a shaker. 0.5 g of this mixture and 20 g of ferrite carrier (F-150, manufactured by Powder Tech Co., Ltd.) were placed in a 50 mL glass bottle, and the bottle was conditioned at 23°C and a relative humidity of 50% for 8 hours (referred to as low-temperature, low-humidity conditions). Similarly, the bottle was conditioned at 50°C and a relative humidity of 95% for 24 hours (referred to as high-temperature, high-humidity conditions).
(2) The mixture was subjected to friction stirring at 50 rpm for 10 minutes and 60 minutes using a Turbulent shaker mixer, and the charge amount after each time was measured using a blow-off charge amount measuring device (manufactured by Kyocera Chemical Corporation).
Using the obtained values, "charge amount after 60 minutes of friction/charge amount after 10 minutes of friction" was calculated, and this was taken as the charge stability index.
A larger charge stability index indicates a more excellent charge retention rate. Under these evaluation conditions, a charge stability index of 0.8 or more is preferable.

<Dispersibility>
The toners obtained in the examples and comparative examples were cut into ultrathin slices of about 100 μm, stained with ruthenium tetroxide, and then observed under a transmission electron microscope (TEM) at a magnification of 3,000 times. The number-average dispersed diameter of the polyester resin (A) in the toner (toner binder) was calculated by image analysis (the diameters of any 10 particles were measured and the average value was calculated) using an image processing device (Keyence Corporation, VHX-700F), and evaluated according to the following criteria.
[Judgment criteria]
◎: Less than 2.0 μm ○: 2.0 μm or more and less than 3.0 μm △: 3.0 μm or more and less than 5.0 μm ×: 5.0 μm or more

<Odor>
1.0 g of the toner was placed in a glass test tube with a lid (φ15 mm×150 mm), sealed, and heated for 5 minutes at 210° C. Thereafter, the lid was removed, and 10 monitors checked the odor and evaluated it according to the following criteria.
[Judgment criteria]
○: 0-1 person answered that it smells bad △: 2-6 people answered that it smells bad ×: 7 or more people answered that it smells bad

As is clear from the evaluation results in Table 4, the toners (T-1) to (T-9) using the toner binders produced in the respective Examples all achieved excellent results in all performance evaluations. On the other hand, the toners (T'-1) and (T'-2) using the toner binders produced in the respective Comparative Examples were poor in some performance items. Specifically, Comparative Example 1 did not satisfy the relational expression |SP _A -SP _B |≦1.0, so the dispersibility of the polyester resin (A) in the crystalline vinyl resin (B) was poor, and furthermore, the charge retention rate at high temperature and high humidity was reduced. Comparative Example 2 contained a polyester resin crosslinked by carbon-carbon bonds, but the content of organic solvent was high because the crosslinking reaction was carried out using the radical polymerization initiator (c), so that the thermal stability was reduced, the charge retention rate at high temperature and high humidity was reduced, and furthermore, the odor was worse.

The toner binder of the present invention is excellent in charge retention rate (particularly charge retention rate under high temperature and high humidity conditions), dispersibility and odor, and can be suitably used as a toner for developing electrostatic images used in electrophotography, electrostatic recording, electrostatic printing and the like.
Further, it is suitable for use as an additive for paints, an additive for adhesives, particles for electronic paper, and the like.

Claims (6)

A toner binder comprising a polyester resin (A) and a crystalline vinyl resin (B), the polyester resin (A) being a reaction product of a polyester resin (A1) and an epoxy compound (E), and further satisfying the following relational formula (1):
|SP _A1 -SP _B |≦1.0 (1)
[wherein SP _A1 represents the solubility parameter (SP value) of the polyester resin (A1), and SP _B represents the SP value of the crystalline vinyl resin (B).] The toner binder according to claim 1, wherein the polyester resin (A) is a resin in which the polyester resin (A1) is crosslinked with an epoxy compound (E). The toner binder according to claim 1 or 2, wherein the crystalline vinyl resin (B) is a polymer containing monomer (a) as an essential constituent monomer, the monomer (a) is a (meth)acrylate having a chain-like hydrocarbon group and having 21 to 40 carbon atoms, and the weight ratio of (a) among the monomers constituting (B) is 30% by weight or more based on the total weight of the monomers constituting (B). The toner binder according to any one of claims 1 to 3, wherein the epoxy compound (E) is a multifunctional epoxy compound having an epoxy equivalent of 150 to 500. The toner binder according to any one of claims 1 to 4, wherein the weight ratio of the epoxy compound (E) to the weight of the polyester resin (A1) is 1 to 35% by weight. 6. The toner binder according to claim 1, wherein the polyester resin (A1) has an acid value of 5 to 50 mgKOH/g.