JP5642566B2 - Toner binder and toner composition - Google Patents

Description

  The present invention relates to a toner binder and a toner composition used for electrophotography, electrostatic recording, electrostatic printing and the like.

The toner binder for electrophotography, which is commonly used as an image fixing method in copying machines, printers, etc., does not fuse the toner to the heat roll even at a high fixing temperature (hot offset resistance), fixing. Toners can be fixed even at low temperatures (low temperature fixability), and storage stability as fine particles (blocking resistance) is required.
In recent years, there is an increasing demand for color, high speed, high reliability, compactness, low cost, and energy savings in copiers and printers. In particular, in order to reduce the environmental load (energy saving), it is urgently necessary to cope with both low-temperature fixing property and blocking resistance of the toner.
For the purpose of improving the fixing performance of these toners, it has been conventionally known that incompatible resins specialized in low temperature range and high temperature range are used as a matrix phase and a domain phase. In addition, a method of adding a compatibilizing agent for compatibilizing the incompatible resin has been proposed for vinyl resins such as styrene polymers (Patent Document 1, etc.).

JP-A-8-328303

However, conventional toners composed of a matrix phase and a domain phase do not sufficiently satisfy all of the fixing property (balance between low temperature fixing property and hot offset resistance) and storage stability. When using an electronic copying machine, a wide range of fixing temperature is particularly required.
An object of the present invention is to provide a toner binder and a toner composition having a wide fixing temperature range and excellent blocking resistance.

As a result of intensive studies to solve these problems, the present inventors have reached the present invention.
That is, in the present invention, a linear polyester resin (A) and a non-linear polyester resin (B) having a peak top molecular weight of 2500 or more, which are incompatible with each other, are formed by polycondensation of a carboxylic acid component (x) and a polyol component (y). ), And a compatibilizer (C1) which is a polymer obtained by reacting or combining at least two incompatible polyester resins and / or a compatibilizer (C2) which is a linear polyester resin having a peak top molecular weight of less than 2500 ), A linear polyester resin (A) is a sea phase, and a non-linear polyester resin (B) is an island phase. The island phase diameter is 100 times that of a phase contrast microscope and / or a digital microscope. the electrophotographic toner binder is 5μm or less in the measurement of the above; as well as the toner binder, a colorant, list , The release agent if necessary, a charge control agent, magnetic powder, and a toner composition containing at least one additive selected from fluidizing agents; a.

  By using the toner binder and the toner composition of the present invention, it is possible to obtain a toner having excellent fixability and to provide a toner binder having excellent toner storage stability (blocking resistance). It became.

The present invention is described in detail below.
The linear polyester resin (A) used in the present invention is obtained by polycondensation of a carboxylic acid component (x) and a polyol component (y). The carboxylic acid component (x) is preferably composed of a polycarboxylic acid (x2) and, if necessary, an aromatic monocarboxylic acid (x1).

  As aromatic monocarboxylic acid (x1), benzoic acid having 7 to 14 carbon atoms and derivatives thereof (derivative means that one or more hydrogen atoms in the aromatic ring of benzoic acid are substituted with organic groups having 1 to 7 carbon atoms. For example, benzoic acid, 4-phenylbenzoic acid, para-tert-butylbenzoic acid, toluic acid, ortho-benzoylbenzoic acid, and naphthoic acid.), And C8-14 A derivative of acetic acid having an aromatic substituent of (the derivative means one having one or more hydrogen atoms other than those contained in the carboxyl group of acetic acid and substituted with an aromatic group having 6 to 12 carbon atoms. For example, diphenylacetic acid, phenoxyacetic acid, and α-phenoxypropionic acid.) May be used, and two or more may be used in combination. Of these, benzoic acid having 7 to 14 carbon atoms and derivatives thereof are preferable, and benzoic acid is more preferable.

  From the viewpoint of storage stability, the aromatic monocarboxylic acid (x1) is preferably 30 mol% or less, more preferably 1 to 25 mol%, particularly preferably 2 to 20 with respect to the total carboxylic acid component (x). Mol%.

  Examples of the polycarboxylic acid (x2) include a dicarboxylic acid (x21) and / or a polycarboxylic acid having 3 to 6 or more valences (x22).

  Examples of the dicarboxylic acid (x21) include alkane dicarboxylic acids having 4 to 36 carbon atoms (for example, succinic acid, adipine, and sebacic acid); alicyclic dicarboxylic acids having 6 to 40 carbon atoms [for example, dimer acid (dimerized linoleic acid)] An alkene dicarboxylic acid having 4 to 36 carbon atoms (for example, alkenyl succinic acid such as dodecenyl succinic acid, malee, fumar, citracone, and mesaconic acid); an aromatic dicarboxylic acid having 8 to 36 carbon atoms (phthal, isophthal, terephthal, and Naphthalenedicarboxylic acid and the like); and ester-forming derivatives thereof [lower alkyl (alkyl group having 1 to 4 carbon atoms: methyl, ethyl, n-propyl, etc.) ester, and acid anhydrides. The same applies below. ]; Etc. may be mentioned, and two or more of them may be used in combination. Among these, preferred are alkene dicarboxylic acids having 4 to 20 carbon atoms and aromatic dicarboxylic acids having 8 to 20 carbon atoms, and ester-forming derivatives thereof, and more preferred are terephthalic acid, isophthalic acid, and / or Alternatively, lower alkyl (alkyl group having 1 to 4 carbon atoms) ester (x211).

Examples of the tricarboxylic acid having a valence of 3 to 6 or more (x22) include aromatic polycarboxylic acids having 9 to 20 carbon atoms (such as trimellitic acid and pyromellitic acid), and aliphatic polycarboxylic acids having 6 to 36 carbon atoms. (Hexane tricarboxylic acid, etc.) and ester-forming derivatives thereof may be mentioned, and two or more of them may be used in combination.
Among these, trimellitic acid and pyromellitic acid, and ester-forming derivatives thereof are preferable.

The content of terephthalic acid, isophthalic acid and / or their lower alkyl (carbon number of alkyl group: 1 to 4) ester (x211) in the polycarboxylic acid (x2) is preferably from the viewpoint of storage stability. It is 85-100 mol%, More preferably, it is 90-100 mol%.
The molar ratio of terephthalic acid and / or its lower alkyl ester to (x211) and isophthalic acid and / or its lower alkyl ester is preferably 20:80 to 100: 0 from the viewpoint of the mechanical strength of the resin. More preferably, it is 25: 75-80: 20.

Examples of the polyol component (y) include a diol (y1) and / or a polyol (y2) having 3 to 8 or more valences.
Examples of the diol (y1) include alkylene glycols having 2 to 36 carbon atoms (ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,6-hexanediol, etc.); C4-C36 alkylene ether glycol (diethylene glycol, triethylene glycol, dipropylene glycol, tripropylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, etc.); C6-C36 alicyclic diol ( 1,4-cyclohexanedimethanol and hydrogenated bisphenol A, etc.); (poly) oxyalkylene of the above alicyclic diol (alkylene having 2 to 4 carbon atoms, the same applies to the following polyoxyalkylene groups) ether [ Kishiarukiren units 1-30 (hereinafter AO unit hereinafter), ethylene oxide, obtained by adding an alkylene oxide having 2 to 4 carbon atoms such as propylene oxide. The same applies below. And polyoxyalkylene ethers (number of AO units 2-30) of dihydric phenols [monocyclic dihydric phenols (for example, hydroquinone) and bisphenols (bisphenol A, bisphenol F, bisphenol S, etc.)], and the like. Two or more kinds may be used in combination.

  Of these, alkylene glycols having 2 to 12 carbon atoms (y11), polyoxyalkylene ethers of bisphenols (number of AO units 2 to 30), and combinations thereof are preferable.

  Examples of the polyol (y2) having 3 to 8 or more valences include 3 to 8 or more aliphatic polyhydric alcohols having 3 to 36 carbon atoms (an alkane polyol and an intramolecular or intermolecular dehydrate thereof such as glycerin, Trimethylolethane, trimethylolpropane, pentaerythritol, sorbitol, sorbitan, polyglycerin, and dipentaerythritol; sugars and derivatives thereof such as sucrose and methylglucoside); (poly) oxyalkylene ethers of the above aliphatic polyhydric alcohols ( Number of AO units 1-30); polyoxyalkylene ether of trisphenols (trisphenol PA, etc.) (number of AO units 2-30); novolac resin (phenol novolac, cresol novolac, etc., average degree of polymerization 3-60) Polio Etc. (the number 2 to 30 of AO units) sialic sharp emission ether and the like, may be used in combination of two or more thereof.

  Among these, preferred are 3 to 8 or higher aliphatic polyhydric alcohols and polyoxyalkylene ethers of novolac resins (number of AO units 2 to 30), and more preferred are polyoxyalkylenes of novolac resins. Ether (number of AO units 2 to 30).

  In the polyol component (y) constituting the linear polyester resin (A), polyoxyalkylene ethers of bisphenols (number of AO units 2 to 30) and polyoxyalkylene ethers of novolak resins (number 2 of AO units 2 to 2) It is preferable to contain an aromatic polyol such as 30).

  A method for producing a linear polyester resin (A) by polycondensing a carboxylic acid component (x) composed of a polycarboxylic acid (x2) and optionally an aromatic monocarboxylic acid (x1) and a polyol component (y). Is not particularly limited, and (x2) and, if necessary, (x1) and (y) can be polycondensed together, but when (x1) and (x2) are used in combination, (x2) ) And (y) are polycondensed in an equivalent ratio such that the hydroxyl group of (y) is excessive, and then the hydroxyl group of the resulting polycondensate (A0) and the carboxyl group of (x1) And may be further polycondensed. If necessary, after polycondensation of (A0) and (x1), a polycarboxylic acid having 3 to 6 or more valences (x22) may be added and further polycondensed.

The polycondensation of the carboxylic acid component (x) and the polyol component (y) when producing the linear polyester resin (A) can be performed using a known esterification reaction method. As a general method, for example, in the presence of a polymerization catalyst in an inert gas (nitrogen gas or the like) atmosphere, the reaction temperature is preferably 150 to 280 ° C, more preferably 180 to 270 ° C, and particularly preferably 200 to 260. It can carry out by making it react at ° C. The reaction time is preferably 30 minutes or longer, particularly 2 to 40 hours from the viewpoint of reliably performing the polycondensation reaction.
It is also effective to reduce the pressure in order to improve the reaction rate at the end of the reaction.
The ratio of all polyol components (y) and all carboxylic acid components (x) used in the production of (A) is preferably 2/1 as an equivalent ratio [OH] / [COOH] of hydroxyl groups to carboxyl groups. ½, more preferably 1.5 / 1 to 1 / 1.3, particularly preferably 1.3 / 1 to 1 / 1.2.

As the polymerization catalyst for obtaining the linear polyester resin (A), a polymerization catalyst containing at least one metal selected from titanium, antimony, zirconium, nickel, and aluminum is used from the viewpoint of reactivity and environmental protection. Preferably, a titanium-containing catalyst is used.
Examples of the titanium-containing catalyst include titanium alkoxide, potassium oxalate titanate, titanium terephthalate, and catalysts described in JP-A-2006-243715 [titanium dihydroxybis (triethanolamate), titanium monohydroxytris (triethanolaminate). And their intramolecular polycondensates], and catalysts described in JP-A 2007-11307 (titanium tributoxy terephthalate, titanium triisopropoxy terephthalate, titanium diisopropoxy diterephthalate, etc.) and the like. .
Antimony trioxide etc. are mentioned as an antimony containing catalyst.
Zirconyl acetate etc. are mentioned as a zirconium containing catalyst.
Nickel acetylacetonate etc. are mentioned as a nickel containing catalyst.
Examples of the aluminum-containing catalyst include aluminum hydroxide and aluminum triisopropoxide.

The amount of the catalyst added is desirably determined as appropriate so as to maximize the reaction rate. The addition amount is preferably 10 ppm to 1.9%, more preferably 100 ppm to 1.7%, based on the total raw materials. The amount added is preferably 10 ppm or more, so that the reaction rate is increased.
In the above and the following, “%” means “% by weight” unless otherwise specified.

  The acid value (mgKOH / g, the same applies hereinafter) of the linear polyester resin (A) is preferably 0 to 60, more preferably 1 to 55, and particularly preferably 2 to 50. When the acid value is 60 or less, the charging characteristics at the time of toner formation do not deteriorate.

The hydroxyl value (mgKOH / g, the same applies hereinafter) of the linear polyester resin (A) is preferably 0 to 125, more preferably 1 to 100. When the hydroxyl value is 125 or less, the hot offset resistance at the time of toner formation becomes better.
The acid value and hydroxyl value in the present invention are measured by the method defined in JIS K0070.

  The peak top molecular weight (hereinafter referred to as Mp) of the linear polyester resin (A) is usually 2500 or more, preferably 2500 to 15000, more preferably 2550 to 13000, and particularly preferably 2600 to 12000. When the Mp is less than 2500, the resin strength necessary for fixing is insufficient, and when it is 15000 or less, the low-temperature fixability at the time of toner formation is good.

Above and below, the peak top molecular weight (Mp) of the polyester resin is measured under the following conditions using gel permeation chromatography (GPC).
Device (example): Tosoh HLC-8120
Column (example): TSKgelGMHXL (2)
TSKgelMultiporeHXL-M (1 pc.)
Measurement temperature: 40 ° C
Measurement solution: 0.25% tetrahydrofuran (THF) solution Injection amount: 100 μl
Detector: Refractive index detector Reference material: TSK standard polystyrene (manufactured by Tosoh)
Molecular weight = 4480000, 2890000, 1090000, 355
000, 190000, 96400, 37900, 1810
A total of 12 points of 0, 9100, 2800, 1050, and 500. The molecular weight showing the maximum peak height on the obtained chromatogram is referred to as peak top molecular weight (Mp). The molecular weight of the polyester resin is measured by dissolving the polyester resin in a THF solvent and filtering the insoluble matter with a glass filter.

Further, the softening point [Tm] of the linear polyester resin (A) is preferably 70 to 120 ° C, more preferably 75 to 110 ° C, and particularly preferably 80 to 100 ° C. In this range, the balance between hot offset resistance and low-temperature fixability is good.
Tm is a value measured as follows.
Using a descending flow tester {for example, CFT-500D, manufactured by Shimadzu Corporation), a load of 1.96 MPa was applied by a plunger while heating a measurement sample of 1 g at a heating rate of 6 ° C./min. Extrude from a nozzle with a diameter of 1 mm and a length of 1 mm, draw a graph of “plunger descent amount (flow value)” and “temperature”, and graph the temperature corresponding to 1/2 of the maximum plunger descent amount This value (temperature when half of the measurement sample flows out) is taken as the softening point [Tm].

The glass transition temperature [Tg] of the linear polyester resin (A) used in the present invention is preferably 45 ° C. or higher from the viewpoint of storage stability. From the viewpoint of low-temperature fixability, the low-temperature fixability at the time of toner formation is good when it is 75 ° C. or lower.
In addition, in the above and below, Tg is measured by the method (DSC method) prescribed | regulated to ASTM D3418-82 using Seiko Denshi Kogyo Co., Ltd. DSC20, SSC / 580.

  The tetrahydrofuran (THF) insoluble content in the linear polyester resin (A) is preferably 5% or less from the viewpoint of low-temperature fixability during toner formation. More preferably, it is 4% or less, and particularly preferably 3% or less.

The THF-insoluble matter in the present invention is determined by the following method.
Add 50 ml of THF to 0.5 g of the sample and stir to reflux for 3 hours. After cooling, the insoluble content is filtered off with a glass filter, and the resin content on the glass filter is dried under reduced pressure at 80 ° C. for 3 hours. The insoluble matter is calculated from the weight of the dried resin content on the glass filter and the weight ratio of the sample.

  The toner binder for electrophotography of the present invention contains a non-linear polyester resin (B) together with a linear polyester resin (A) from the viewpoint of achieving both low-temperature fixability and offset resistance.

The nonlinear polyester resin (B) used in the present invention is obtained by polycondensation of a carboxylic acid component (x) and a polyol component (y). The carboxylic acid component (x) is preferably composed of a polycarboxylic acid (x2) and, if necessary, an aromatic monocarboxylic acid (x1).
(B) is usually the above tricarboxylic acid or higher polycarboxylic acid (x22) together with the dicarboxylic acid (x21) and optionally the aromatic monocarboxylic acid (x1) and the diol (y1). ) And / or a trivalent to octavalent or higher polyol (y2).

Polyol component (y) [In this section, it means a polyol component which is a constituent unit of the non-linear polyester resin (B) excluding those removed outside the system during the polycondensation reaction. The proportion of alkylene glycol having 2 to 12 carbon atoms (y11) is preferably 85 to 100 mol%, more preferably 90 to 100 mol%, from the viewpoint of mechanical strength.
In particular, the content of ethylene glycol in (y) is preferably 90 to 100 mol%, more preferably 95 to 100 mol%, and particularly preferably 100 mol% from the viewpoint of mechanical strength.

  The aromatic monocarboxylic acid (x1) is preferably 30 mol% or less, more preferably 1 to 25 mol%, particularly preferably 2 with respect to the total carboxylic acid component (x) from the viewpoint of storage stability. ~ 20 mol%.

  Moreover, the sum total of 3-8 valence or more polyol (y2) and 3-6 valence or more polycarboxylic acid (x22) in the sum total of a carboxylic acid component (x) and a polyol component (y). Is preferably 0.1 to 15 mol%, more preferably 0.2 to 12 mol%. When the amount is 0.1 mol% or more, the storage stability of the toner is good, and when the amount is 15 mol% or less, the charging characteristics of the toner are good.

  A method for producing a nonlinear polyester resin (B) by polycondensation of a carboxylic acid component (x) composed of a polycarboxylic acid (x2) and optionally an aromatic monocarboxylic acid (x1) and a polyol component (y) Is not particularly limited, and (x2) and, if necessary, (x1) and (y) can be polycondensed together, but when (x1) and (x2) are used in combination, (x2) ) And (y) are polycondensed in an equivalent ratio such that the hydroxyl group of (y) is excessive, and then the hydroxyl group of the obtained polycondensate (B0) and the carboxyl group of (x1) It is preferable to carry out polycondensation by reacting. If necessary, after the polycondensation of (B0) and (x1), a polycarboxylic acid having 3 to 6 or more valences (x22) may be added and further polycondensed.

The reaction conditions for the polycondensation of the carboxylic acid component (x) and the polyol component (y) and the polymerization catalyst used when producing the nonlinear polyester resin (B) are the same as those for the linear polyester resin (A). .
In the first stage, when the polycondensation of at least a part of the polycarboxylic acid (x2) and the polyol component (y), the reaction ratio between (y) and at least a part of (x2) is a hydroxyl group and a carboxyl. The group equivalent ratio [OH] / [COOH] is preferably 2/1 to 1/1, more preferably 1.5 / 1 to 1.01 / 1, and particularly preferably 1.3 / 1 to 1.02. / 1.
The ratio of all polyol components (y) and all carboxylic acid components (x) used in the production of (B) is preferably 2/1 as an equivalent ratio [OH] / [COOH] of hydroxyl groups to carboxyl groups. ½, more preferably 1.5 / 1 to 1 / 1.3, particularly preferably 1.3 / 1 to 1 / 1.2.

  The glass transition temperature [Tg] of the non-linear polyester resin (B) is preferably 45 ° C to 80 ° C, and more preferably 50 ° C to 70 ° C. When Tg is 80 ° C. or lower, the low-temperature fixability is improved. Moreover, blocking resistance is favorable in Tg being 45 degreeC or more.

  The softening point [Tm] of (B) is not particularly limited, but is preferably 90 ° C to 170 ° C, and more preferably 120 ° C to 160 ° C. When Tm is 90 ° C. or higher, the hot offset resistance is good, and when Tm is 170 ° C. or lower, the fixability is good.

  The Mp of the tetrahydrofuran (THF) soluble part of the nonlinear polyester resin (B) is preferably 2000 to 12000, and more preferably 3000 to 10,000.

  The THF insoluble content in the nonlinear polyester resin (B) is preferably 3 to 50% from the viewpoint of low temperature fixability. More preferably, it is 5 to 40%, and particularly preferably 10 to 35%. When the THF-insoluble content is 50% or less, the glossiness (gloss) of the image is good.

The acid value of the non-linear polyester resin (B) is preferably 3 to 40, more preferably 10 to 38, and the hydroxyl value is preferably 0 to 30, and more preferably 0 to 10.
The sum of the acid value and the hydroxyl value of the nonlinear polyester resin (B) is preferably 3 to 40, more preferably 10 to 40, and particularly preferably 20 to 39. When the sum of the acid value and the hydroxyl value is 3 or more, the storage stability is good, and when it is 40 or less, the charging stability is improved.

  The weight ratio [(A) / (B)] of the linear polyester resin (A) and the non-linear polyester resin (B) is preferably 90/10 in terms of both low-temperature fixability, hot offset resistance and grindability. -20/80, more preferably 80 / 20-25 / 75.

The toner binder for electrophotography of the present invention may contain a resin other than (A) and (B) as long as the effects of the present invention are not impaired. Other resins include polyester resins other than (A) and (B), vinyl resins [copolymers of styrene and alkyl (meth) acrylate, copolymers of styrene and diene monomers, etc.], epoxy resins ( Bisphenol A diglycidyl ether ring-opening polymer), urethane resin (polyaddition product of the polyol component and diisocyanate, etc.) and the like.
Among these, polyester resins other than (A) and (B) are preferable. The Mp of other resins is preferably 300 to 100,000.

The toner binder for electrophotography of the present invention further contains a compatibilizing agent (C1) and / or a compatibilizing agent (C2).
The compatibilizing agent (C1) is a polymer obtained by reacting or combining at least two incompatible polyester resins, and is any of a random copolymer, a block copolymer, a graft copolymer, and the like. May be.
As (C1), the linear polyester resin (A) and the nonlinear polyester resin (B) forming the sea-island structure are at least partly a random copolymer containing the same structural unit, or the sea-island structure is configured. A block copolymer or graft copolymer having a structural unit that is compatible with all of the phases or any of the phases is preferred.

Here, incompatible means a case where the difference (ΔSP value) in solubility parameter value (SP value) between polyester resins is 1.0 or more.
The value of the solubility parameter (SP value [(cal / cm ³ ) ^1/2 ]) in the present invention is calculated by the calculation formula [Polymer Engineering and Science, Vol. 14, no. 2, pp. 147 to 154 (Feb. 1974)].

  The reason for using the compatibilizing agent (C1) made of a polymer obtained by reacting or combining the above two types of incompatible polyester resins is to reduce the interfacial free energy between the phases, and further to the diameter of the continuous phase having a sea-island structure. This is because the effect of drastically improving the interaction at the interface of the continuous phase by stabilizing the particle size is greatly improved, so that the low-temperature fixability, the offset resistance and the like can be drastically improved.

  The glass transition temperature [Tg] of (C1) is preferably 45 ° C to 70 ° C, more preferably 50 ° C to 65 ° C. When Tg is 70 ° C. or lower, the low-temperature fixability is improved. Moreover, blocking resistance is favorable in Tg being 45 degreeC or more.

  Mp of (C1) is preferably 2000 to 15000, more preferably 2500 to 12000, and particularly preferably 3000 to 10,000. When the Mp is 2000 or more, the resin strength necessary for fixing is expressed, and when it is 15000 or less, the low-temperature fixability at the time of toner formation is good.

  The acid value of (C1) is preferably 1 to 100, more preferably 2 to 80, particularly preferably 5 to 60. When the acid value is 1 or more, the low-temperature fixability at the time of toner formation is good, and when it is 100 or less, the charging characteristics at the time of toner formation do not deteriorate.

  The hydroxyl value of (C1) is preferably 10 to 125, more preferably 20 to 100. When the hydroxyl value is 125 or less, the hot offset resistance at the time of toner formation becomes better.

  The softening point [Tm] of (C1) is preferably 70 to 120 ° C, more preferably 75 to 110 ° C, and particularly preferably 80 to 100 ° C. In this range, the balance between hot offset resistance and low-temperature fixability is good.

The compatibilizing agent (C1) can be obtained, for example, by reacting an incompatible polyester resin having an acid value and a polyester resin having a hydroxyl value.
Specifically, for example, (A) and (B) forming a sea-island structure, or a linear polyester resin containing a composition constituting (A) and a linear polyester resin containing a composition constituting (B), It can be produced by melt kneading using a roll mill, kneader or extruder, lab plast mill, etc., or using a known esterification or transesterification reaction in a polymerization tank or glass tube oven.
As a general method, for example, in an inert gas (nitrogen gas or the like) atmosphere, in the presence of the polymerization catalyst, the reaction temperature is preferably 150 to 280 ° C, more preferably 180 to 270 ° C, and particularly preferably 200 to 200 ° C. The reaction can be carried out at 260 ° C. The reaction time is preferably 30 minutes or more, particularly 2 to 40 hours from the viewpoint of reliably performing the reaction. It is also effective to reduce the pressure in order to improve the reaction rate.

Further, two or more kinds of polyesters are prepared by reacting a hydroxyl group of one kind of polyester resin with a variety of known diisocyanate compounds and at least one other kind of polyester resin in a solvent or in a non-solvent. It can also be obtained by a method of synthesizing a block or graft copolymer in which a resin is bonded with a diisocyanate.
As the reaction conditions at this time, the reaction is carried out in an inert gas (nitrogen gas or the like) atmosphere at a reaction temperature of preferably 40 to 120 ° C., more preferably 60 to 115 ° C., particularly preferably 80 to 110 ° C. be able to. The reaction time is preferably 30 minutes or more, particularly 2 to 40 hours from the viewpoint of reliably performing the reaction.

As said diisocyanate, C6-C20 aromatic diisocyanate, C2-C18 aliphatic diisocyanate, C4-C15 alicyclic diisocyanate, C-carbon (excluding carbon in NCO group, the same applies hereinafter) 8-15 araliphatic diisocyanates and mixtures of two or more thereof.
Specific examples of the aromatic diisocyanate include 1,3- and / or 1,4-phenylene diisocyanate, 2,4- and / or 2,6-tolylene diisocyanate (TDI), 2,4'- and / or 4,4'-diphenylmethane diisocyanate (MDI), 1,5-naphthylene diisocyanate and the like can be mentioned.
Specific examples of the aliphatic polyisocyanate include ethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate (HDI), and lysine diisocyanate.
Specific examples of the alicyclic diisocyanate include isophorone diisocyanate (IPDI), dicyclohexylmethane-4,4′-diisocyanate (hydrogenated MDI), cyclohexylene diisocyanate, and methylcyclohexylene diisocyanate (hydrogenated TDI).
Specific examples of the araliphatic diisocyanate include m- and / or p-xylylene diisocyanate (XDI), α, α, α ′, α′-tetramethylxylylene diisocyanate (TMXDI), and the like.
Of these, preferred are TDI, MDI, HDI, hydrogenated MDI, and IPDI.

The compatibilizing agent (C2) is a linear polyester resin having an Mp of less than 2500. (C2) is obtained by polycondensing the carboxylic acid component (x) composed of the polycarboxylic acid (x2) and, if necessary, the aromatic monocarboxylic acid (x1) and the polyol component (y). A polyester resin is preferred.
Examples of the polyol component (y) include bisphenol A, acetylated product of bisphenol A, bisphenol S, acetylated product of bisphenol S, polyoxyalkylene ether of bisphenol S (2 to 4 oxyalkylene units), and hydrogenated bisphenol A. One or more types selected from the group consisting of (y *), the diol (y1) other than (y *), and 3 to 8 or more polyols (y2).

  Bisphenol A in the polyol component (y), acetylated product of bisphenol A, bisphenol S, acetylated product of bisphenol S, polyoxyalkylene ether of bisphenol S (number of oxyalkylene units 2 to 4), and hydrogenated bisphenol A The content of one or more diols (y *) selected from the group is preferably at least 30 mol%, more preferably at least 45 mol%, particularly preferably at least 60 mol%, from the viewpoint of storage stability.

  The compatibilizing agent (C2) in the present invention can be produced in the same manner as the production method of the linear polyester resin (A).

  The compatibilizing agent (C2) used in the present invention has the effect of a fixing aid because it has a low molecular weight in addition to the compatibility and has a low melt viscosity and excellent low-temperature fixability.

As for the acid value of (C2) used for this invention, 0-20 are preferable, More preferably, it is 0-15. When the acid value is 20 or less, the charging characteristics are good.
The hydroxyl value of (C2) is preferably 0 to 130, more preferably 0 to 110, and particularly preferably 0 to 50. When the hydroxyl value is 130 or less, the hot offset resistance becomes better.

  The glass transition temperature [Tg] of (C2) is preferably 45 ° C to 80 ° C, more preferably 50 ° C to 70 ° C. When the Tg is 80 ° C. or lower, the low-temperature fixability is better, and when the Tg is 45 ° C. or higher, the blocking resistance is good.

  The softening point [Tm] of (C2) is not particularly limited, but is preferably 60 ° C to 110 ° C, more preferably 70 ° C to 100 ° C. When Tm is 60 ° C. or higher, the hot offset resistance is good, and when Tm is 110 ° C. or lower, the fixability is good.

  (C2) preferably has a difference (Tm−Tg) between the softening point [Tm] (° C.) and the glass transition temperature [Tg] (° C.) of 35 ° C. or less. (Tm−Tg) is more preferably 34 ° C. or lower. When (Tm−Tg) is 35 ° C. or lower, the low-temperature fixability is better.

  Mp of the tetrahydrofuran (THF) soluble part of (C2) is less than 2500, preferably 2480 or less, more preferably 1000 to 2400. When Mp is 2500 or more, the low-temperature fixability is lowered.

  Weight ratio of linear polyester resin (A), nonlinear polyester resin (B) and compatibilizer (C1) and / or (C2) [(A) :( B) :( C1) and / or (C2), total 100. ] Is preferably (9-79) :( 15-90) :( 0.1-8), more preferably (20), from the viewpoint of achieving both low-temperature fixability, hot offset resistance and grindability. -75) :( 20-70) :( 1-5).

In the toner binder for electrophotography of the present invention, the linear polyester resin (A) and the nonlinear polyester resin (B) are incompatible with each other. The toner binder of the present invention preferably has a sea-island structure in which (A) and (B) are evenly mixed, (A) is a sea phase, and (B) is an island phase. It can be observed with a phase contrast microscope or a digital microscope (high resolution optical microscope) that (A) and (B) are incompatible and have a sea-island structure.
Evaluation of the mixing property of the linear polyester resin (A) and the non-linear polyester resin (B) is based on the phase difference between the diameter of the island phase of the sea-island structure in which (A) in the toner binder is the sea phase and (B) is the island phase. Evaluation can be performed by observing at a magnification of 100 times or more (preferably 100 to 5000 times) of a microscope and / or a digital microscope (high resolution optical microscope). Since the toner particle size is usually about 5 to 10 μm, if it is 5 μm or less, it is judged that the mixing property is good. The diameter of the island phase is more preferably 4 μm or less, particularly preferably 0.1 to 3 μm. When the dispersed particle diameter is 5 μm or less, the low-temperature fixability and the hot offset resistance are good.
In the above and the following, the evaluation of the mixing property is measured using an IX71 phase contrast microscope (an inverted research microscope) manufactured by OLYMPUS and / or a digital microscope manufactured by Keyence (high resolution zoom lens VH-Z500R / Z500W). .

  The toner composition of the present invention contains the electrophotographic toner binder of the present invention and a colorant, and if necessary, one or more additives such as a release agent, a charge control agent, a magnetic powder, and a fluidizing agent.

As the colorant, all of dyes and pigments used as toner colorants can be used. Specifically, carbon black, iron black, Sudan Black SM, First Yellow G, Benzidine Yellow, Pigment Yellow, Indian First 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, etc. Or 2 or more types can be mixed and used.
Further, if necessary, magnetic powder (a powder of a ferromagnetic metal such as iron, cobalt, nickel, or a compound such as magnetite, hematite, ferrite) can also be included as a colorant.

  As the mold release agent, those having a softening point [Tm] of 50 to 170 ° C. are preferable, such as polyolefin wax, natural wax, aliphatic alcohol having 30 to 50 carbon atoms, fatty acid having 30 to 50 carbon atoms and a mixture thereof. Can be mentioned. Polyolefin waxes include (co) polymers [obtained by (co) polymerization] of olefins (for example, ethylene, propylene, 1-butene, isobutylene, 1-hexene, 1-dodecene, 1-octadecene, and mixtures thereof). And olefin (co) polymer oxides with oxygen and / or ozone, maleic acid modifications of olefin (co) polymers [eg maleic acid and its derivatives (maleic anhydride, Modified products such as monomethyl maleate, monobutyl maleate and dimethyl maleate), olefins and unsaturated carboxylic acids [such as (meth) acrylic acid, itaconic acid and maleic anhydride] and / or unsaturated carboxylic acid alkyl esters [(meta ) Alkyl acrylate (alkyl 1 to 1 carbon atoms) 8) esters and maleic acid alkyl (C1-18 alkyl) copolymers of an ester, etc.] or the like, and Sasol wax.

  Examples of natural waxes include carnauba wax, montan wax, paraffin wax, and rice wax. Examples of the aliphatic alcohol having 30 to 50 carbon atoms include triacontanol. Examples of the fatty acid having 30 to 50 carbon atoms include triacontane carboxylic acid.

  As charge control agents, nigrosine dyes, triphenylmethane dyes containing tertiary amines as side chains, quaternary ammonium salts, polyamine resins, imidazole derivatives, quaternary ammonium base-containing polymers, metal-containing azo dyes, copper phthalocyanine dyes , Salicylic acid metal salts, boron complexes of benzylic acid, sulfonic acid group-containing polymers, fluorine-containing polymers, halogen-substituted aromatic ring-containing polymers, and the like.

  Examples of the fluidizing agent include colloidal silica, alumina powder, titanium oxide powder, and calcium carbonate powder.

  The composition ratio of the toner composition of the present invention is preferably 30 to 97%, more preferably 40 to 95%, particularly preferably 45 to 92% of the electrophotographic toner binder of the present invention based on the toner weight; The agent is preferably 0.05 to 60%, more preferably 0.1 to 55%, particularly preferably 0.5 to 50%; among the additives, the release agent is preferably 0 to 30%, and further Preferably 0.5 to 20%, particularly preferably 1 to 10%; the charge control agent is preferably 0 to 20%, more preferably 0.1 to 10%, particularly preferably 0.5 to 7.5%. The fluidizing agent is preferably 0 to 10%, more preferably 0 to 5%, and particularly preferably 0.1 to 4%. The total content of additives is preferably 3 to 70%, more preferably 4 to 58%, and particularly preferably 5 to 50%. When the composition ratio of the toner is in the above range, a toner having good chargeability can be easily obtained.

The toner composition of the present invention may be obtained by any conventionally known method such as a kneading and pulverizing method, an emulsion phase inversion method, or a polymerization method. For example, when a toner is obtained by a kneading and pulverizing method, the components constituting the toner excluding the fluidizing agent are dry blended, and then melt-kneaded, then coarsely pulverized, and finally atomized using a jet mill pulverizer or the like. By further classifying, the particle size (D50) can be preferably made into fine particles having a particle size of 5 to 20 μm, and then mixed with a fluidizing agent. The average particle size (D50) (D50 is the particle size when the number larger than a certain particle size in the volume particle size distribution of powder represents 50% of the total number of powders) is Coulter counter [ For example, it is measured using a product name: Multisizer III (manufactured by Coulter).
When the toner is obtained 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. it can. The volume average particle diameter of the toner is preferably 3 to 15 μm.

  The toner composition of the present invention is mixed with carrier particles such as iron powder, glass beads, nickel powder, ferrite, magnetite, and ferrite whose surface is coated with a resin (acrylic resin, silicone resin, etc.) as necessary. Used as a developer for a latent image. The weight ratio of toner to carrier particles is preferably 1/99 to 100/0. Further, instead of the carrier particles, it can be rubbed with a member such as a charging blade to form an electric latent image.

The toner composition of the present invention is fixed on a support (paper, polyester film, etc.) by a copying machine, a printer, or the like to form a recording material. As a method for fixing to the support, a known hot roll fixing method, flash fixing method, or the like can be applied.
A fixing method, a flash fixing method, or the like can be applied.

  EXAMPLES The present invention will be further described below with reference to examples, but the present invention is not limited thereto. Hereinafter, a part shows a weight part.

Production Example 1
[Synthesis of Linear Polyester Resin (A-1)]
In a reaction vessel equipped with a cooling pipe, a stirrer and a nitrogen introduction pipe, 235 parts of terephthalic acid, propylene oxide adduct of bisphenol A: Newpol BP-2P (manufactured by Sanyo Chemical Industries: 2 mol adduct of propylene oxide) Then, 140 parts of benzoic acid and 3 parts of titanium diisopropoxybistriethanolamate as a polymerization catalyst were added and reacted at 210 ° C. for 5 hours while distilling off the water generated under a nitrogen stream, and then under reduced pressure of 5 to 20 mmHg. The reaction was continued until the acid value was 2 or less. Subsequently, 35 parts of trimellitic anhydride was added, and the mixture was reacted for 1 hour under normal pressure. The obtained resin was cooled to room temperature and then pulverized into particles. This is designated as linear polyester resin (A-1).
Mp of (A-1) was 5000, Tg was 62 ° C., Tm was 95 ° C., acid value was 25, and hydroxyl value was 1.

Production Example 2
[Synthesis of Linear Polyester Resin (A-2)]
In a reaction vessel equipped with a cooling tube, a stirrer and a nitrogen introduction tube, 260 parts of terephthalic acid, propylene oxide adduct of bisphenol A: Newpol BP-2P · 795 parts, 30 parts of benzoic acid, titanium diisosodium as a polymerization catalyst Add 3 parts of propoxybistriethanolamate, react for 5 hours while distilling off the water generated at 210 ° C under a nitrogen stream, and then react under reduced pressure of 5 to 20 mmHg until the acid value is 2 or less. Reacted and removed. The obtained resin was cooled to room temperature and then pulverized into particles. This is designated as linear polyester resin (A-2).
Mp of (A-2) was 2600, Tg was 50 ° C., Tm was 87 ° C., acid value was 2, and hydroxyl value was 40.

Production Example 3
[Synthesis of Nonlinear Polyester Resin (B-1)]
In a reaction vessel equipped with a condenser, a stirrer and a nitrogen introduction tube, 388 parts of terephthalic acid, 388 parts of isophthalic acid, 21 parts of adipic acid, 600 parts of ethylene glycol, titanium diisopropoxybistriethanolamate as a polymerization catalyst 5 parts was added and reacted for 5 hours while distilling off the water generated at 210 ° C. under a nitrogen stream, and then reacted for 1 hour under reduced pressure of 5 to 20 mmHg. Subsequently, 17 parts of benzoic acid was added and reacted for 3 hours under normal pressure [linear polyester resin (B-1a)]. Further, 57 parts of trimellitic anhydride was added and reacted under normal pressure for 1 hour, and then reacted under reduced pressure of 20 to 40 mmHg and taken out at a predetermined softening point. The recovered ethylene glycol was 280 parts. The obtained resin was cooled to room temperature and then pulverized into particles. This is designated as polyester resin (B-1).
Mp of (B-1) was 8000, Tg was 60 ° C., Tm was 145 ° C., the acid value was 26, and the hydroxyl value was 1. In addition, Mp of (B-1a) was 4,500, the acid value was 1, and the hydroxyl value was 50.

Production Example 4
[Synthesis of Non-Linear Polyester Resin (B-2)]
In a reaction vessel equipped with a cooling tube, a stirrer and a nitrogen introduction tube, 530 parts of terephthalic acid, 130 parts of isophthalic acid, 5 parts of adipic acid, 650 parts of ethylene glycol, titanium diisopropoxybistriethanolamate as a polymerization catalyst 5 parts was added and reacted for 5 hours while distilling off the water generated at 210 ° C. under a nitrogen stream, and then reacted for 1 hour under reduced pressure of 5 to 20 mmHg. Subsequently, 55 parts of benzoic acid was added and reacted under normal pressure for 3 hours [linear polyester resin (B-2a)]. Further, 85 parts of trimellitic anhydride was added and reacted under normal pressure for 1 hour, and then reacted under reduced pressure of 20 to 40 mmHg and taken out at a predetermined softening point. The recovered ethylene glycol was 280 parts. The obtained resin was cooled to room temperature and then pulverized into particles. This is designated as polyester resin (B-2).
Mp of (B-2) was 4500, Tg was 58 ° C., Tm was 143 ° C., acid value was 25, and hydroxyl value was 10. In addition, Mp of (B-2a) was 2200, the acid value was 1, and the hydroxyl value was 85.

Production Example 5
[Synthesis of Compatibilizer (C1-1)]
In a reaction vessel equipped with a cooling pipe, a stirrer and a nitrogen introduction pipe, 250 parts of linear polyester resin (A-1) and 250 parts of the above linear polyester resin (B-1a), titanium diisopropoxybistriethanol as a polymerization catalyst 0.5 parts of aminate was added, and the reaction was allowed to proceed for 5 hours at 180 ° C. while distilling off the water produced under a nitrogen stream. This is designated as compatibilizing agent (C1-1).
Mp of (C1-1) was 7000, Tg was 60 ° C., Tm was 90 ° C., the acid value was 20, and the hydroxyl value was 40.

Production Example 6
[Synthesis of Compatibilizer (C1-2)]
In a reaction vessel equipped with a cooling tube, a stirrer, and a nitrogen introduction tube, 250 parts of linear polyester resin (A-2) and 500 parts of the linear polyester resin (B-2a), and titanium diisopropoxybistriethanol as a polymerization catalyst 0.5 parts of aminate was added, and the reaction was allowed to proceed for 5 hours at 180 ° C. while distilling off the water produced under a nitrogen stream. This is designated as compatibilizing agent (C1-2).
Mp of (C1-2) was 3,500, Tg was 55 ° C., Tm was 85 ° C., the acid value was 20, and the hydroxyl value was 40.

Production Example 7
[Synthesis of Compatibilizer (C1-3)]
In a reaction vessel equipped with a cooling tube, a stirrer, and a nitrogen introduction tube, 200 parts of linear polyester resin (A-2) was added and dissolved at 100 ° C., and then 20 parts of isophorone diisocyanate was added and reacted for 4 hours. Next, 200 parts of the linear polyester resin (B-1a) was added and reacted for 4 hours. This is designated as compatibilizing agent (C1-3).
Mp of (C1-3) was 6000, Tg was 60 ° C., Tm was 90 ° C., the acid value was 1, and the hydroxyl value was 20.

Production Example 8
[Synthesis of Compatibilizer (C2-1)]
Place 110 parts of succinic acid, 430 parts of hydrogenated bisphenol A, 100 parts of benzoic acid, and 2.5 parts of titanium diisopropoxybistriethanolamate as a polymerization catalyst in a reaction vessel equipped with a cooling tube, a stirrer and a nitrogen introduction tube. The reaction was carried out for 3 hours while distilling off the water produced under a nitrogen stream at 210 ° C., followed by reaction under reduced pressure of 5 to 20 mmHg until the acid value was 2 or less. Further, 15 parts of trimellitic anhydride was added and reacted for 1 hour under normal pressure. The obtained resin was cooled to room temperature and then pulverized into particles. This is designated as compatibilizer and fixing aid (C2-1).
Tg of (C2-1) was 59 ° C., Tm was 90 ° C. (Tm-Tg: 31 ° C.), Mp was 1800, acid value was 14, and hydroxyl value was 18.

Production Example 9
[Synthesis of Compatibilizer (C2-2)]
In a reaction vessel equipped with a cooling pipe, a stirrer and a nitrogen introduction pipe, 110 parts of phthalic anhydride, 400 parts of bisphenol S / ethylene oxide 2-mole adduct, 85 parts of benzoic acid, titanium diisopropoxybistriethanolamine as a polymerization catalyst After adding 2.5 parts of the nate and reacting for 3 hours while distilling off the water generated at 210 ° C. under a nitrogen stream, the reaction is performed under reduced pressure of 5 to 20 mmHg, and the reaction is continued until the acid value becomes 2 or less. It was. The obtained resin was cooled to room temperature and then pulverized into particles. This is designated as compatibilizing agent (C2-2).
Tg of (C2-2) was 58 ° C., Tm was 91 ° C. (Tm-Tg: 33 ° C.), Mp was 2,400, the acid value was 1, and the hydroxyl value was 30.

Production Example 10
[Synthesis of Compatibilizer (C2-3)]
In a reaction vessel equipped with a cooling tube, a stirrer and a nitrogen introduction tube, 170 parts of phthalic anhydride, 470 parts of bisphenol S / ethylene oxide 2 mol adduct, 2.5 parts of titanium diisopropoxybistriethanolamate as a polymerization catalyst The reaction was carried out for 3 hours while distilling off the water produced under a nitrogen stream at 210 ° C., followed by reaction under reduced pressure of 5 to 20 mmHg until the acid value was 2 or less. The obtained resin was cooled to room temperature and then pulverized into particles. This is designated as compatibilizer (C2-3).
Tg of (C2-3) was 58 ° C., Tm was 92 ° C. (Tm-Tg: 34 ° C.), Mp was 2450, acid value was 1, and hydroxyl value was 110.

Comparative production example 1
[Compatibilizer for comparison (RC-1)]
Ethylene oxide adduct of bisphenol A: Newpol BPE-20 (manufactured by Sanyo Chemical Industries, Mp = 327) was used as a compatibilizing agent (RC-1) for comparison.

Examples 1-14, Comparative Examples 1-3
Linear polyester resin (A), nonlinear polyester resin (B), comparative linear polyester resin (RA), comparative nonlinear polyester resin (RB), compatibilizer obtained in Production Examples 1 to 10 and Comparative Production Example 1 (C1), the compatibilizing agent (C2), and the compatibilizing agent (RC) for comparison are put in a plastmill at the ratio (parts) shown in Table 1, stirred at 140 ° C. for 10 minutes, and melt-mixed. Binders (TB-1) to (TB-14) and comparative toner binders (TB′-1) to (TB′-3) were obtained. To 100 parts of each toner binder, 8 parts of cyanine blue KRO (manufactured by Sanyo Dye) and 5 parts of carnauba wax are added. The toner was made by the following method.
First, after pre-mixing using a Henschel mixer [FM10B manufactured by Mitsui Miike Chemical Co., Ltd.], the mixture was kneaded using a twin-screw kneader [PCM-30 manufactured by Ikegai Co., Ltd.]. Next, the mixture was finely pulverized using a supersonic jet crusher lab jet [manufactured by Nippon Pneumatic Industry Co., Ltd.] and then classified by an airflow classifier [MDS-I made by Nippon Pneumatic Industry Co., Ltd.] Toner particles having (D50) of 8 μm were obtained. Next, 100 parts of the toner particles are mixed with 0.5 part of colloidal silica (Aerosil R972: manufactured by Nippon Aerosil Co., Ltd.) using a sample mill, and the toner compositions (T1) to (T14) of the present invention and a comparative toner composition are mixed. (T′-1) to (T′-3) were obtained.

[Evaluation method]
[1] Minimum fixing temperature (MFT)
An unfixed image developed using a commercial copying machine (AR5030; manufactured by Sharp) was evaluated using a fixing machine of a commercial copying machine (AR5030; manufactured by Sharp). The fixing roll temperature at which the residual ratio of the image density after rubbing the fixed image with a pad becomes 70% or more was set as the minimum fixing temperature.
[2] Hot offset generation temperature (HOT)
The fixing was evaluated in the same manner as the MFT, and the presence or absence of hot offset on the fixed image was visually evaluated. The fixing roll temperature at which hot offset occurred was defined as the hot offset occurrence temperature.
Regarding the minimum fixing temperature (MFT) and hot offset occurrence temperature (HOT), it is important that the fixing temperature range (difference between HOT and MFT) is wide. [3] Storage stability (blocking resistance)
Each toner composition is put in a polyethylene bottle, kept in a constant temperature water bath at 45 ° C. for 8 hours, transferred to a 42 mesh sieve, and shaken for 10 seconds at a vibration strength of 5 using a powder tester manufactured by Hosokawa Micron Corporation. Then, the weight percentage of the toner remaining on the sieve was measured and judged according to the following criteria to evaluate the storage stability.
Residual toner weight%
◎: 0% or more and less than 15% ○: 15% or more and less than 25% Δ: 25% or more and less than 30% ×: 30% or more [4] Mixability evaluation According to the above method.

  Since the toner composition of the present invention using the toner binder for electrophotography of the present invention is excellent in fixing temperature range and storage stability, it is useful as a toner used for electrophotography, electrostatic recording, electrostatic printing and the like. .

Claims (9)

A linear polyester resin (A) and a non-linear polyester resin (B) having a peak top molecular weight of 2500 or more, which are incompatible with each other, formed by polycondensation of the carboxylic acid component (x) and the polyol component (y), and at least two incompatible polyester resin is formed by reacting or binding polymers in which the compatibilizer (C1) and / or peak top molecular weight of 2500 less than the linear polyester resin in which the compatibilizer (C2) containing the In addition, the linear polyester resin (A) has a sea-island structure where the non-linear polyester resin (B) is an island phase, and the diameter of the island phase is 5 μm in a measurement with a magnification of 100 times or more with a phase contrast microscope and / or a digital microscope. The toner binder for electrophotography which is the following .   The carboxylic acid component (x) constituting the linear polyester resin (A) and / or the nonlinear polyester resin (B) is a polycarboxylic acid (x2) and optionally an aromatic monocarboxylic acid (x1). Toner bander.   The polyol component (y) constituting the linear polyester resin (A) contains an aromatic polyol, and 85 to 100 mol% of the polyol component (y) constituting the nonlinear polyester resin (B) is alkylene having 2 to 12 carbon atoms. The toner bander according to claim 1, which is glycol (y11).   The toner bander according to any one of claims 1 to 3, wherein the compatibilizing agent (C1) has a glass transition temperature of 45 to 70 ° C and a softening point of 70 to 120 ° C.   The glass transition temperature [Tg] of the compatibilizer (C2) is 45 to 80 ° C., the relationship between [Tg] and the softening point [Tm] is Tm−Tg ≦ 35 (° C.), and the acid value is 0 to The toner bander according to claim 1, wherein the toner bander is 20 (mg KOH / g) or less.   Polyester obtained by polycondensing a carboxylic acid component (x) composed of a polycarboxylic acid (x2) and optionally an aromatic monocarboxylic acid (x1) and a polyol component (y) as a compatibilizing agent (C2) Resin, wherein bisphenol A, acetylated product of bisphenol A, bisphenol S, acetylated product of bisphenol S, polyoxyalkylene ether of bisphenol S (number of oxyalkylene units 2 to 4), and hydrogen in polyol component (y) The toner bander according to any one of claims 1 to 5, comprising 30 mol% or more of one or more types (y *) selected from the group consisting of bisphenol A.   The toner bander according to any one of claims 1 to 6, wherein the nonlinear polyester resin (B) has a glass transition temperature of 45C to 80C and a softening point of 90C to 170C.   The weight ratio of (A), (B), (C1) and / or (C2) is (9-79) :( 15-90) :( 0.1-8) Or a toner bander as described. A toner composition comprising the toner binder according to any one of claims 1 to 8 , a colorant, and, if necessary, one or more additives selected from a release agent, a charge control agent, a magnetic powder, and a fluidizing agent. .