Method for producing toner binder and method for producing toner

Abstract

To provide a method for manufacturing a toner binder that contains a crystalline polyester (A) and an amorphous polyester (B), wherein the toner binder excels in the dispersibility of the crystalline polyester in the amorphous polyester.SOLUTION: Provided is a method for manufacturing a toner binder that contains a crystalline polyester (A) and an amorphous polyester (B), in which the peak top temperature (Tm) of endothermic peak of the crystalline polyester (A) that is measured by a differential scanning calorimetric analyzer (DSC) is 100-150°C, the toner binder manufacturing method including a step (1) for kneading the crystalline polyester (A) and the amorphous polyester (B) at the peak top temperature (Tm) of endothermic peak of the crystalline polyester (A) or below.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for producing a toner binder and a method for producing a toner. [Background technology]

[0002] In recent years, along with the promotion of miniaturization, speedup, higher image quality and higher reliability of electrophotographic apparatuses, there has been a strong demand for improved low-temperature fixability of toners from the viewpoint of energy conservation, namely, reducing energy consumption in the fixing process. The toner binder has a significant effect on the above-mentioned toner characteristics, and known examples include polystyrene resin, styrene-acrylic resin, polyester resin, epoxy resin, polyurethane resin, and polyamide resin. Recently, polyester resin has been attracting particular attention because it is easy to achieve a balance between storage stability and fixability. For example, a toner has been proposed in which a crystalline polyester resin and an amorphous resin are kneaded at low temperatures with the aim of achieving low-temperature fixability (see Patent Document 1). However, when the particle size of the toner is reduced to meet the demand for higher image reliability such as higher fixing strength, the dispersibility of the crystalline polyester resin in the toner using the above-mentioned crystalline polyester resin is not sufficient, and improvement is desired. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-189871 Summary of the Invention [Problem to be solved by the invention]

[0004] The present invention aims to provide a method for producing a toner binder and a toner containing a crystalline polyester (A) and an amorphous polyester (B), which method has excellent dispersibility of the crystalline polyester in the amorphous polyester. [Means for solving the problem]

[0005] The present inventors have conducted extensive research and have arrived at the present invention. That is, the present invention provides a method for producing a toner binder containing a crystalline polyester (A) and an amorphous polyester (B), the method comprising the steps of: the crystalline polyester (A) is a crystalline polyester containing an aliphatic diol having 2 to 24 carbon atoms and terephthalic acid in a total amount of 60 to 100 mol % based on the total number of moles of the raw material monomers of (A), The peak top temperature (Tm) of the endothermic peak of the crystalline polyester (A) measured by a differential scanning calorimeter (DSC) is 120~130℃ and the method includes a step (1) of kneading the crystalline polyester (A) and the amorphous polyester (B) at a temperature equal to or lower than the peak top temperature (Tm) of the endothermic peak of the crystalline polyester (A). the difference (Tm-Tk) between the temperature (Tk) at which the crystalline polyester (A) and the amorphous polyester (B) are kneaded in the step (1) and the peak top temperature (Tm) of the endothermic peak of the crystalline polyester (A) is 10 to 50°C; A method for producing a toner binder. [Effects of the Invention]

[0006] The method for producing a toner binder and a toner of the present invention is a method for producing a toner binder and a toner containing a crystalline polyester (A) and an amorphous polyester (B), and has the effect of being able to obtain a toner binder and a toner in which the crystalline polyester has excellent dispersibility in the amorphous polyester. [Brief explanation of the drawings]

[0007] [Figure 1] 1 shows TEM images (magnifications of 1000 and 3000) of the toner binders obtained in Examples 1 and 2 and Comparative Examples 1 and 2. DETAILED DESCRIPTION OF THE INVENTION

[0008] The present invention provides a method for producing a toner binder containing a crystalline polyester (A) and an amorphous polyester (B), the method comprising: a step (1) of kneading the crystalline polyester (A) and the amorphous polyester (B) at a temperature equal to or lower than the peak top temperature (Tm) of the endothermic peak of the crystalline polyester (A), wherein the crystalline polyester (A) has a peak top temperature (Tm) of 100 to 150°C as measured by a differential scanning calorimeter (DSC).

[0009] In the present invention, the polyester resin is a polycondensate of a polyol and a polycarboxylic acid. The production method of the present invention is a method for producing a toner binder containing a crystalline polyester (A) and an amorphous polyester (B). In the present invention, "crystalline" means that in differential scanning calorimetry (also referred to as DSC measurement), the DSC curve has a peak top temperature (Tm) of an endothermic peak. The method for measuring the peak top temperature (Tm) of the endothermic peak is described below. Measurement is performed using a differential scanning calorimeter (e.g., DSC Q20, manufactured by TA Instruments, Inc.). The sample is first heated from 30°C to 180°C at 10°C / min, then cooled from 180°C to 0°C at 10°C / min, and then heated a second time from 0°C to 180°C at 10°C / min. The top temperature of the endothermic peak during the second heating process is taken as the peak top temperature (Tm) of the endothermic peak.

[0010] The crystalline polyester (A) in the present invention is a crystalline polyester resin obtained by polycondensation of a component containing an alcohol component and a carboxylic acid component. From the viewpoint of low-temperature fixability and heat-resistant storage stability, it is preferably a crystalline polyester obtained from two or more alcohol components and / or two or more carboxylic acid components. The alcohol component includes a diol and a polyol having three or more valences, and the carboxylic acid component includes a dicarboxylic acid and a polycarboxylic acid having three or more valences.

[0011] Examples of diols include linear aliphatic diols having 2 to 20 carbon atoms (ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, 1,9-nonanediol, 1,10-decanediol, 1,12-dodecanediol, 1,13-tridecanediol, 1,14-tetradecanediol, 1,15-pentadecanediol, 1,18-octadecanediol, 1,19-nonadecanediol, and 1,20-eicosanediol), and alicyclic diols having 6 to 36 carbon atoms (1,2-cyclohexanediol, 1,4-cyclohexanediol, 1,1-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, 5-norbornene-2,3- dimethanol, hydrogenated bisphenol A, spiroglycol, isosorbide, and alkylene oxide (hereinafter, "alkylene oxide" may be abbreviated as AO) adducts of the above-mentioned alicyclic diols, and aromatic diols (1,3-benzenedimethanol, 1,4-benzenedimethanol, bisphenol A, bisphenol F, bisphenol B, bisphenol AD, bisphenol S, trichlorobisphenol A, tetrachlorobisphenol A, dibromobisphenol F, 2-methylbisphenol A, 2,6-dimethylbisphenol A, 2,2'-diethylbisphenol F, and alkylene oxide adducts of the above-mentioned aromatic diols, and the like).

[0012] Examples of trihydric or higher polyols include polyhydric aliphatic alcohols (alkane polyols and their intramolecular or intermolecular dehydration products, such as glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, sorbitol, sorbitan, and polyglycerin; sugars and their esters, such as sucrose and methyl glucoside); AO adducts (number of moles added: 2 to 30) of trisphenols (trisphenol PA, etc.); AO adducts (number of moles added: 2 to 30) of novolak resins (phenol novolak, cresol novolak, etc.); and acrylic polyols [copolymers of hydroxyethyl (meth)acrylate and other vinyl monomers, etc.].

[0013] Of the above alcohol components, from the viewpoint of low-temperature fixability and heat-resistant storage stability, linear aliphatic diols having 2 to 20 carbon atoms are preferred, and linear aliphatic diols having 2 to 12 carbon atoms are more preferred.

[0014] Examples of dicarboxylic acids include linear aliphatic dicarboxylic acids having 2 to 50 carbon atoms (such as succinic acid, adipic acid, sebacic acid, azelaic acid, dodecanedioic acid, and 1,18-octadecanedicarboxylic acid), alicyclic dicarboxylic acids having 8 to 36 carbon atoms (such as 1,4-cyclohexanedicarboxylic acid), and aromatic dicarboxylic acids having 8 to 36 carbon atoms (such as phthalic acid, isophthalic acid, and terephthalic acid).

[0015] Examples of trivalent or higher polycarboxylic acids include aromatic polycarboxylic acids having 9 to 20 carbon atoms (such as trimellitic acid and pyromellitic acid).

[0016] Of the above carboxylic acid components, from the viewpoints of low-temperature fixability and heat-resistant storage stability, linear aliphatic dicarboxylic acids having 2 to 50 carbon atoms and aromatic dicarboxylic acids having 8 to 36 carbon atoms are preferred, and linear aliphatic dicarboxylic acids having 2 to 10 carbon atoms and aromatic dicarboxylic acids having 8 to 10 carbon atoms are more preferred.

[0017] In the present invention, it is preferable that 50 mol% or more of all alcohol components used in the crystalline polyester (A) are aromatic dicarboxylic acids having 8 to 10 carbon atoms, more preferably 75 mol% or more, and even more preferably 95 mol% or more.

[0018] In the present invention, terephthalic acid preferably accounts for 50 mol % or more, more preferably 75 mol % or more, and even more preferably 95 mol % or more of the total alcohol components used in the crystalline polyester (A).

[0019] The reaction ratio of the alcohol component to the carboxylic acid component, expressed as the molar ratio of hydroxyl groups to carboxyl groups {[OH] / [COOH]}, is preferably 1 / 2 to 2 / 1, more preferably 1 / 1.3 to 1.5 / 1, and even more preferably 1 / 1.2 to 1.4 / 1. The hydroxyl groups are those derived from the alcohol component.

[0020] In the present invention, the crystalline polyester (A) can be produced in the same manner as known polyester production methods. For example, it can be produced by reacting components containing an alcohol component and a carboxylic acid component 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. In order to ensure that the polycondensation reaction is carried out, the reaction time is preferably 30 minutes or more, more preferably 2 to 40 hours. It is also effective to reduce the pressure to improve the reaction rate at the end of the reaction.

[0021] In this case, an esterification catalyst can be used if necessary. Examples of the esterification catalyst include tin-containing catalysts (e.g., dibutyltin oxide), antimony trioxide, titanium-containing catalysts (e.g., titanium alkoxide, potassium oxalate titanate, titanium terephthalate, titanium terephthalate alkoxide, the catalysts described in JP-A-2006-243715 (titanium diisopropoxybistriethanolaminate, titanium dihydroxybistriethanolaminate, titanium monohydroxytristriethanolaminate, titanyl bistriethanolaminate, and intramolecular polycondensates thereof), and the catalysts described in JP-A-2007-11307 (titanium tributoxyterephthalate, titanium triisopropoxyterephthalate, titanium diisopropoxyditerephthalate), etc.), zirconium-containing catalysts (e.g., zirconyl acetate), and zinc acetate. Among the esterification catalysts, titanium-containing catalysts are preferred from the viewpoint of low-temperature fixability, and the catalysts described in JP-A Nos. 2006-243715 and 2007-11307 are more preferred.

[0022] The peak top temperature (Tm) of the endothermic peak of the crystalline polyester (A) in the present invention is 100 to 150°C, preferably 110 to 140°C, and more preferably 120 to 130°C. If the melting point is 100° C. or higher, the image strength is good, and if it is 150° C. or lower, the low-temperature fixability is good. For example, if the crystalline polyester (A) is a crystalline polyester containing 60 to 100 mol % in total of an aliphatic diol having 2 to 24 carbon atoms and terephthalic acid, based on the total molar number of the raw material monomers of (A), it becomes easy to achieve the peak top temperature (Tm) of the endothermic peak.

[0023] The viscosity of the crystalline polyester (A) in the present invention at 100° C. is preferably 10 to 10,000 mPa·s, more preferably 400 to 7,000 mPa·s. If the viscosity at 100° C. is 10 mPa·s or more, the heat-resistant storage stability is good, and if it is 10,000 mPa·s or less, the low-temperature fixability is good.

[0024] The ester group concentration of the crystalline polyester (A) in the present invention is preferably 40 to 60% by weight, more preferably 45 to 55% by weight, based on the weight of (A). When the ester group concentration is within the above range, compatibility with the amorphous polyester (B) is good, and low-temperature fixability is excellent. The ester group concentration of the crystalline polyester (A) based on the weight of (A) can be calculated from the number of ester groups [-C(=O)O-] in (A) and is defined as the weight percentage of the ester groups present in 1 g of (A). The actual ester group concentration can be calculated by determining the monomer composition and the number of ester groups constituting (A) using nuclear magnetic resonance spectroscopy (NMR) or the like, or by determining the number of ester groups from the ratio of the amounts of raw materials used in the production of (A).

[0025] The endothermic amount of the crystalline polyester (A) is preferably 5 to 70 J / g, more preferably 40 to 60 J / g. If the endothermic amount is 5 J / g or more, the low-temperature fixability is good, and if it is 70 J / g or less, the heat-resistant storage stability is good.

[0026] The acid value of the crystalline polyester (A) is preferably 0 to 75 mgKOH / g, more preferably 0 to 35 mgKOH / g.

[0027] The hydroxyl value of the crystalline polyester (A) is preferably 0 to 120 mgKOH / g, more preferably 5 to 20 mgKOH / g.

[0028] The number average molecular weight (hereinafter sometimes abbreviated as Mn) of the crystalline polyester (A) is preferably 1,000 to 1,000,000, more preferably 2,000 to 50,000.

[0029] The weight average molecular weight (hereinafter sometimes abbreviated as Mw) of the crystalline polyester (A) is preferably 8,000 to 10,000,000, and more preferably 10,000 to 20,000. If Mw is 10,000 or more, the fixing strength is good, and if it is 20,000 or less, the low-temperature fixing property is good.

[0030] The resin composition of the amorphous polyester (B) in the present invention is not particularly limited as long as it is an amorphous polyester that is a polycondensation product of an alcohol component (x) and a carboxylic acid component (y). In the present invention, "amorphous" means that when the transition temperature of a sample is measured using a differential scanning calorimeter, there is no peak top temperature of the endothermic peak.

[0031] The alcohol component (x) of the amorphous polyester (B) includes a diol (g) and a trihydric or higher polyol (h). Examples of the carboxylic acid component (y) include dicarboxylic acids (i), trivalent or higher polycarboxylic acids (j), and acid anhydrides or lower alkyl esters thereof.

[0032] Examples of the diol (g) include alkylene glycols having 2 to 36 carbon atoms, alkylene ether glycols having 4 to 36 carbon atoms, alicyclic diols having 4 to 36 carbon atoms, alkylene oxide adducts of alkylene glycols or alicyclic diols, alkylene oxide adducts of bisphenols, polylactone diols, and polybutadiene diols. Specific examples of alkylene glycols having 2 to 36 carbon atoms include ethylene glycol, 1,2-propanediol (propylene glycol), 1,3-propanediol, 1,4-butanediol, 1,6-hexanediol, octanediol, decanediol, dodecanediol, tetradecanediol, neopentyl glycol, and 2,2-diethyl-1,3-propanediol. Specific examples of alkylene ether glycols having 4 to 36 carbon atoms include diethylene glycol, triethylene glycol, dipropylene glycol, polyethylene glycol, polypropylene glycol, and polytetramethylene ether glycol. Specific examples of the alicyclic diol having 4 to 36 carbon atoms include 1,4-cyclohexanedimethanol and hydrogenated bisphenol A. In the alkylene oxide adduct of an alkylene glycol or an alicyclic diol, examples of the alkylene glycol or alicyclic diol include those mentioned above, and examples of the alkylene oxide include an ethylene oxide (hereinafter abbreviated as EO) adduct, a propylene oxide (hereinafter abbreviated as PO) adduct, and a butylene oxide (hereinafter abbreviated as BO) adduct. Examples of alkylene oxide adducts of bisphenol include AO (EO, PO, BO, etc.) adducts of bisphenol A, bisphenol F, bisphenol S, etc. (number of moles added: 2 to 30). Examples of polylactone diols include poly-ε-caprolactone diol.

[0033] Examples of the trihydric or higher polyol (h) include trihydric or higher polyhydric aliphatic alcohols having 3 to 36 carbon atoms, AO adducts of polyhydric aliphatic alcohols (number of moles added: 2 to 120), AO adducts of trisphenols (trisphenol PA, etc.) (number of moles added: 2 to 30), AO adducts of novolak resins (phenol novolak, cresol novolak, etc.) (number of moles added: 2 to 30), and acrylic polyols [copolymers of hydroxyethyl (meth)acrylate and other vinyl monomers, etc.]. Examples of polyhydric aliphatic alcohols having 3 to 36 carbon atoms and at least three valences include alkane polyols and their intramolecular or intermolecular dehydration products, as well as sugars (such as sucrose) and compounds in which part of the alcohol in the sugar is alkyl etherified. Specific examples of alkane polyols and their intramolecular or intermolecular dehydration products include glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, sorbitol, sorbitan, and polyglycerin.

[0034] Of the alcohol components (x), alkylene glycols having 2 to 36 carbon atoms and alkylene oxide adducts of bisphenols are preferred, and AO adducts of bisphenol A are more preferred, from the viewpoints of low-temperature fixability and heat-resistant storage stability.

[0035] Examples of the dicarboxylic acid (i) include alkanedicarboxylic acids having 4 to 36 carbon atoms, alkenylsuccinic acids, alicyclic dicarboxylic acids having 6 to 40 carbon atoms, alkenedicarboxylic acids having 4 to 36 carbon atoms, and aromatic dicarboxylic acids having 8 to 36 carbon atoms. Examples of the alkanedicarboxylic acid having 4 to 36 carbon atoms include succinic acid, adipic acid, sebacic acid, azelaic acid, dodecanedicarboxylic acid, octadecanedicarboxylic acid, and decylsuccinic acid. Examples of alkenyl succinic acids include dodecenyl succinic acid, pentadecenyl succinic acid, and octadecenyl succinic acid. Examples of the alicyclic dicarboxylic acid having 6 to 40 carbon atoms include dimer acid (dimerized linoleic acid). Examples of the alkene dicarboxylic acid having 4 to 36 carbon atoms include maleic acid, fumaric acid, and citraconic acid. Examples of aromatic dicarboxylic acids having 8 to 36 carbon atoms include phthalic acid, isophthalic acid, terephthalic acid, and naphthalenedicarboxylic acid.

[0036] Examples of the trivalent or higher polycarboxylic acid (j) include aromatic polycarboxylic acids having 9 to 20 carbon atoms (trimellitic acid, pyromellitic acid, etc.) and aliphatic (including alicyclic) tricarboxylic acids having 6 to 36 carbon atoms (hexanetricarboxylic acid, decanetricarboxylic acid, etc.).

[0037] As the dicarboxylic acid (i) or trivalent or higher polycarboxylic acid (j), acid anhydrides or lower alkyl esters having 1 to 4 carbon atoms (methyl ester, ethyl ester, isopropyl ester, etc.) of the above-mentioned compounds may also be used.

[0038] Of the carboxylic acid components (y), from the viewpoints of low-temperature fixability and heat-resistant storage stability, preferred are alkanedicarboxylic acids having 4 to 36 carbon atoms, aromatic dicarboxylic acids having 8 to 36 carbon atoms, and aromatic polycarboxylic acids having 9 to 20 carbon atoms, and more preferred are alkanedicarboxylic acids having 4 to 20 carbon atoms, aromatic dicarboxylic acids having 8 to 20 carbon atoms, and trimellitic acid.

[0039] The reaction ratio of the alcohol component (x) to the carboxylic acid component (y), expressed as the molar ratio of hydroxyl groups to carboxyl groups {[OH] / [COOH]}, is preferably 1 / 2 to 2 / 1, more preferably 1 / 1.3 to 1.5 / 1, and even more preferably 1 / 1.2 to 1.4 / 1. The hydroxyl groups are those derived from the alcohol component.

[0040] In the present invention, the amorphous polyester (B) can be produced in the same manner as the crystalline polyester (A) by a known polyester production method.

[0041] The glass transition temperature (hereinafter abbreviated as Tg) of the amorphous polyester (B) is preferably 20 to 90° C., more preferably 40 to 80° C. If it is 20° C. or higher, the toner has excellent heat-resistant storage stability, and if it is 90° C. or lower, the toner has little inhibition of low-temperature fixability.

[0042] The acid value of the amorphous polyester (B) is preferably 0 to 75 mgKOH / g, more preferably 7 to 24 mgKOH / g.

[0043] The hydroxyl value of the amorphous polyester (B) is preferably 0 to 120 mgKOH / g, more preferably 1 to 70 mgKOH / g.

[0044] The number average molecular weight (hereinafter sometimes abbreviated as Mn) of the amorphous polyester (B) is preferably 1,000 to 1,000,000, and more preferably 2,000 to 8,000.

[0045] The weight average molecular weight (hereinafter sometimes abbreviated as Mw) of the amorphous polyester (B) is preferably 2,000 to 200,000, more preferably 4,000 to 150,000.

[0046] The 1 / 2 drop temperature of the amorphous polyester (B) is preferably 80 to 170°C, more preferably 95 to 150°C. Two or more types of amorphous polyester (B) having different 1 / 2 temperature drop may be used in combination. A combination of one having a 1 / 2 temperature drop of 80°C or more and less than 115°C and one having a 1 / 2 temperature drop of 115°C or more and 170°C or less is preferred, and a combination of one having a 1 / 2 temperature drop of 85°C or more and 115°C or less and one having a 1 / 2 temperature drop of 120°C or more and 160°C or less is more preferred.

[0047] In the present invention, the weight ratio of the amorphous polyester (B) having a half drop temperature of 80° C. or more and less than 115° C. to the amorphous polyester (B) having a half drop temperature of 115° C. or more and 170° C. or less is preferably 50:50 to 80:20.

[0048] In the method for producing a toner binder of the present invention, other binder resins may be contained in addition to the crystalline polyester (A) and the amorphous polyester (B). Examples of such other resins include polyurethane resins, styrene resins, and epoxy resins. From the viewpoint of heat-resistant storage stability, polyurethane resins are preferred.

[0049] Examples of polyurethane resins include polyaddition products of diol (g) and polyisocyanate, and polyaddition products of the above-mentioned amorphous polyester and polyisocyanate.

[0050] Examples of polyisocyanates include aromatic polyisocyanates having 6 to 20 carbon atoms (excluding carbon atoms in NCO groups, the same applies below), aliphatic polyisocyanates having 2 to 18 carbon atoms, alicyclic polyisocyanates having 4 to 15 carbon atoms, aromatic aliphatic polyisocyanates having 8 to 15 carbon atoms, modified products of these polyisocyanates (such as modified products containing a urethane group, a carbodiimide group, an allophanate group, a urea group, a biuret group, a uretdione group, a uretoimine group, an isocyanurate group, or an oxazolidone group), and mixtures of two or more of these.

[0051] Specific examples of aromatic polyisocyanates having 6 to 20 carbon atoms include 1,3- or 1,4-phenylene diisocyanate, 2,4- or 2,6-tolylene diisocyanate (TDI), crude TDI, 2,4'- or 4,4'-diphenylmethane diisocyanate (MDI), crude MDI, 1,5-naphthylene diisocyanate, 4,4',4"-triphenylmethane triisocyanate, and m- or p-isocyanatophenylsulfonyl isocyanate.

[0052] Specific examples of aliphatic polyisocyanates having 2 to 18 carbon atoms include ethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate (HDI), dodecamethylene diisocyanate, 1,6,11-undecane triisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, lysine diisocyanate, 2,6-diisocyanatomethyl caproate, bis(2-isocyanatoethyl)fumarate, bis(2-isocyanatoethyl)carbonate, and 2-isocyanatoethyl-2,6-diisocyanatohexanoate.

[0053] Specific examples of the alicyclic polyisocyanate having 4 to 15 carbon atoms include isophorone diisocyanate (IPDI), dicyclohexylmethane-4,4'-diisocyanate (hydrogenated MDI), cyclohexylene diisocyanate, methylcyclohexylene diisocyanate (hydrogenated TDI), bis(2-isocyanatoethyl)-4-cyclohexene-1,2-dicarboxylate, and 2,5- and / or 2,6-norbornane diisocyanate.

[0054] Specific examples of the aromatic aliphatic polyisocyanate having 8 to 15 carbon atoms include m- and / or p-xylylene diisocyanate (XDI) and α,α,α',α'-tetramethylxylylene diisocyanate (TMXDI). Furthermore, examples of the modified polyisocyanate include modified products containing a urethane group, a carbodiimide group, an allophanate group, a urea group, a biuret group, a uretdione group, a uretoimine group, an isocyanurate group, and an oxazolidone group. Specifically, these include modified MDI (urethane-modified MDI, carbodiimide-modified MDI, trihydrocarbyl phosphate-modified MDI, etc.), modified polyisocyanates such as urethane-modified TDI, and mixtures of two or more of these (for example, a combination of modified MDI and urethane-modified TDI (isocyanate-containing prepolymer)).

[0055] Of these polyisocyanates, preferred are aromatic polyisocyanates having 6 to 20 carbon atoms, aliphatic polyisocyanates having 2 to 18 carbon atoms, and alicyclic polyisocyanates having 4 to 15 carbon atoms, more preferred are aromatic polyisocyanates having 6 to 15 carbon atoms, aliphatic polyisocyanates having 4 to 12 carbon atoms, and alicyclic polyisocyanates having 6 to 15 carbon atoms, and particularly preferred are TDI, MDI, HDI, hydrogenated MDI, and IPDI.

[0056] The method for producing a toner binder of the present invention is a method for producing a toner binder containing the crystalline polyester (A) and the amorphous polyester (B), and includes a step (1) of kneading the crystalline polyester (A) and the amorphous polyester (B) at a temperature equal to or lower than the peak top temperature (Tm) of the endothermic peak of the crystalline polyester (A). By kneading a crystalline polyester (A) having a high endothermic peak top temperature (Tm) of 100 to 150°C with an amorphous polyester (B) at a temperature equal to or lower than the endothermic peak top temperature (Tm), a toner binder with excellent dispersibility of the crystalline polyester in the amorphous polyester can be obtained. Crystalline polyester (A) with a high endothermic peak top temperature (Tm) of 100 to 150°C will first melt and then crystallize when kneaded at a temperature higher than the endothermic peak top temperature (Tm). It is believed that the high melting point causes rapid crystal growth after kneading, resulting in large crystals and poor dispersibility. On the other hand, when kneaded at a temperature lower than the endothermic peak top temperature (Tm), the crystalline polyester (A) does not melt and remains crystalline, dispersing finely due to shear during kneading, resulting in superior dispersibility.

[0057] The difference (Tm-Tk) between the temperature (Tk) at which the crystalline polyester (A) and the amorphous polyester (B) are kneaded in the step (1) and the peak top temperature (Tm) of the endothermic peak of the crystalline polyester (A) is preferably 10 to 50°C, more preferably 20 to 30°C, from the viewpoint of dispersibility of the crystalline polyester.

[0058] The time (resin residence time) for kneading the crystalline polyester (A) and the amorphous polyester (B) in the step (1) is preferably 30 to 300 seconds, more preferably 30 to 60 seconds, from the viewpoint of dispersibility of the crystalline polyester.

[0059] In the step (1), the kneading equipment can be a general equipment capable of kneading a resin while adjusting the temperature, such as a twin-screw kneader.

[0060] In the method for producing a toner binder of the present invention, the weight ratio (A / B) of the crystalline polyester (A) to the amorphous polyester (B) is preferably 5 / 95 to 20 / 80 from the viewpoint of image strength.

[0061] The toner binder obtained by the production method of the present invention may be used to obtain resin particles for toner. The content of the toner binder in the resin particles is preferably 30 to 97% by weight, more preferably 42 to 96% by weight, and even more preferably 50 to 95% by weight, based on the weight of the resin particles.

[0062] The resin particles may be mixed with various known additives such as colorants, release agents, charge control agents, and fluidizing agents, if necessary.

[0063] The colorant preferably contains one or more selected from the group consisting of black colorants, blue colorants, red colorants, and yellow colorants. As the colorant, any dye, pigment, etc. used as a colorant for toner can be used. Specific examples include carbon black, iron black, Sudan Black SM, Fast Yellow G, Benzidine Yellow, Solvent Yellow (e.g., 21, 77, and 114), Pigment Yellow (e.g., 12, 14, 17, and 83), India First Orange, Irgasin Red, Paranitoaniline Red, Toluidine Red, Solvent Red (e.g., 17, 49, 128, 5, 13, 22, and 48·2), Disperse Red, Carmine FB, Pigment Orange R, Lake Red 2G, Rhodamine FB, Rhodamine B Lake, Methyl Violet B Lake, Phthalocyanine Blue, Solvent Blue (e.g., 25, 94, 60, and 15·3), Pigment Blue, Brilliant Green, Phthalocyanine Green, Oil Yellow GG, Kayaset YG, Orasol Brown B, and Oil Pink OP. If necessary, magnetic powder (powder of ferromagnetic metals such as iron, cobalt and nickel, and compounds such as magnetite, hematite and ferrite) may be contained to also function as a colorant. The content of the colorant is preferably 1 to 40 parts by weight, more preferably 2 to 15 parts by weight, based on 100 parts by weight of the total binder resin for the toner of the present invention. When a magnetic powder is used, the content of the magnetic powder is preferably 20 to 150 parts by weight, more preferably 30 to 120 parts by weight, based on 100 parts by weight of the total binder resin for the toner.

[0064] Examples of the release agent include natural waxes (beeswax, carnauba wax, montan wax, etc.), petroleum waxes (paraffin wax, microcrystalline wax, petrolatum, etc.), synthetic waxes (Fischer-Tropsch wax, polyethylene wax, polypropylene wax, oxidized polyethylene wax, oxidized polypropylene wax, etc.), and synthetic ester waxes (fatty acid esters synthesized from fatty acids having 10 to 30 carbon atoms and alcohols having 10 to 30 carbon atoms), and it is preferable to contain one or more types selected from the group consisting of these release agents. The content of the release agent is preferably 0 to 30% by weight, more preferably 0.5 to 20% by weight, and even more preferably 1 to 10% by weight, based on 100 parts by weight of the total of the toner binder resin of the present invention.

[0065] When using the above-mentioned release agent, a modified wax may be used in combination, if necessary. The modified wax is a release agent to which a vinyl polymer chain has been grafted. The release agents used in the modified wax include those similar to those used in the above-mentioned release agents, and the preferred ones are also similar. Examples of vinyl monomers constituting the vinyl polymer chain of the modified wax include styrene and methacrylic acid esters. The vinyl polymer chain may be a homopolymer or copolymer of a vinyl monomer. The content of the modified wax is preferably 0 to 15% by weight, more preferably 0.5 to 10% by weight, and even more preferably 1 to 5% by weight, based on 100 parts by weight of the total of the binder resin for the toner of the present invention.

[0066] The charge control agent may be either a positively charged charge control agent or a negatively charged charge control agent, and examples thereof include nigrosine dyes, triphenylmethane dyes containing tertiary amines as side chains, quaternary ammonium salts, polyamine resins, imidazole derivatives, and quaternary ammonium salts. Examples of the charge control agent include ammonium base-containing polymers, metal-containing azo dyes, copper phthalocyanine dyes, metal salicylate salts, boron complexes of benzilic acid, sulfonic acid group-containing polymers, fluorine-containing polymers, and halogen-substituted aromatic ring-containing polymers. The content of the charge control agent may be 0 to 20% by weight, preferably 0.1 to 10% by weight, and more preferably 0.5 to 7.5% by weight, based on 100 parts by weight of the total of the binder resin for the toner of the present invention.

[0067] Examples of fluidizing agents include silica, titania, alumina, fatty acid metal salts, silicone resin particles, and fluororesin particles, and two or more of these may be used in combination. From the viewpoint of toner chargeability, silica is preferred. From the viewpoint of toner transferability, the silica is preferably hydrophobic. The content of the fluidizing agent may be 0 to 10% by weight, preferably 0 to 5% by weight, and more preferably 0.1 to 4% by weight, based on 100 parts by weight of the total of the toner binder resin of the present invention.

[0068] The total weight of additives such as colorants, release agents, charge control agents, and fluidizing agents may be 3 to 70% by weight, preferably 4 to 58% by weight, and more preferably 5 to 50% by weight, based on the weight of the resin particles.

[0069] The volume average particle diameter (D50) of the resin particles is preferably 1 to 15 μm, more preferably 2 to 10 μm, and particularly preferably 3 to 7 μm. By keeping it within the above range, low-temperature fixability is improved.

[0070] The method for producing the resin particles is not particularly limited, and may be a known kneading and grinding method, a suspension polymerization method described in JP-B No. 10231 / 1961, JP-A No. 53856 / 1984, or JP-A No. 61842 / 1984, an emulsion polymerization method typified by a soap-free polymerization method in which a toner is produced by directly polymerizing a monomer in the presence of a water-soluble polymerization initiator that is soluble in the monomer, an interfacial polymerization method such as a microcapsule production method, an in-situ polymerization method, a coacervation method, an emulsion aggregation method in which at least one type of fine particles are aggregated to obtain particles of a desired particle size as disclosed in JP-A Nos. 106473 / 1987 and 186253 / 1988, a dispersion polymerization method characterized by monodispersity, a dissolution suspension method in which necessary resins are dissolved in a water-insoluble organic solvent and then converted into resin particles in water, or an ester elongation polymerization method, or a method in which resin particles are dispersed in carbon dioxide in a supercritical state. Among the above manufacturing methods, the emulsion aggregation method in which at least one type of fine particles are aggregated to obtain particles of the desired particle size is preferred from the viewpoint of particle size control and storage stability of resin particles.

[0071] When resin particles are used as toner, they are 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 needed to be used as a developer for electric latent images. When carrier particles are used, the weight ratio of toner to carrier particles is preferably 1 / 99 to 99 / 1. Alternatively, an electric latent image can be formed by friction with a member such as a charging blade instead of carrier particles. The toner does not necessarily contain carrier particles.

[0072] The toner production method of the present invention is a method for producing a toner containing a crystalline polyester (A) and an amorphous polyester (B), the method comprising: kneading the crystalline polyester (A) with the amorphous polyester (B) at a temperature below the endothermic peak top temperature (Tm) of the crystalline polyester (A), as measured by a differential scanning calorimeter (DSC), of 100 to 150°C; and kneading the crystalline polyester (A) with the amorphous polyester (B) at a temperature below the endothermic peak top temperature (Tm) of the crystalline polyester (A). The other steps in the method, other than step (1) of kneading the crystalline polyester (A) with the amorphous polyester (B) at a temperature below the endothermic peak top temperature (Tm), can be carried out using known methods. In the present invention, a crystalline polyester (A) having a high endothermic peak top temperature (Tm) of 100 to 150°C and an amorphous polyester (B) are kneaded at a temperature equal to or lower than the endothermic peak top temperature (Tm), thereby making it possible to obtain a toner in which the crystalline polyester has excellent dispersibility in the amorphous polyester.

[0073] The toner production method of the present invention may include a step (1) of kneading the crystalline polyester (A) and the amorphous polyester (B) at a temperature equal to or lower than the peak top temperature (Tm) of the endothermic peak of the crystalline polyester (A). For example, the method includes the following production methods (i) to (ii): (i) A method of producing a toner by carrying out the above-mentioned method for producing a toner binder, and then mixing various additives such as a colorant, a release agent, a charge control agent, a fluidizing agent, etc. by a known method (preferably at a temperature equal to or lower than the peak top temperature (Tm) of the endothermic peak of (A)). (ii) A method for producing a toner by kneading a crystalline polyester (A), the amorphous polyester (B), and various additives (colorants, release agents, charge control agents, fluidizing agents, etc.) at a temperature equal to or lower than the peak top temperature (Tm) of the endothermic peak of the crystalline polyester (A).

[0074] The toner is fixed to a support (paper, polyester film, etc.) by a copier, printer, etc. to form a recording material. As a method for fixing to a support, known methods such as a heat roll fixing method and a flash fixing method can be used.

[0075] The toner is used for developing electrostatic images or magnetic latent images in electrophotography, electrostatic recording, electrostatic printing, etc. More specifically, it is used for developing electrostatic images or magnetic latent images that are particularly suitable for full color applications. [Example]

[0076] The present invention will be further explained below with reference to examples and comparative examples, but the present invention is not limited thereto. Unless otherwise specified, "parts" below refer to parts by weight.

[0077] The physical properties of the crystalline polyester, amorphous polyester, toner, etc. were measured by the following methods.

[0078] <Peak top temperature (Tm) of the endothermic peak of crystalline polyester> Measurement was performed using a differential scanning calorimeter (e.g., "DSCQ20" [manufactured by TA Instruments, Inc.]). The crystalline polyester was first heated from 30°C to 180°C at 10°C / min, then cooled from 180°C to 0°C at 10°C / min, and then heated a second time from 0°C to 180°C at 10°C / min. The temperature showing the top of the endothermic peak during the second heating process was recorded as the peak top temperature (Tm) of the endothermic peak of the crystalline polyester.

[0079] <Amount of heat absorbed at the endothermic peak of crystalline polyester> In the DSC curve during the second heating process observed under the same measurement conditions as in the measurement of the peak top temperature of the endothermic peak, a straight line was drawn connecting the point closest to the peak on the baseline below the endothermic onset temperature (T0) of the endothermic peak and the point closest to the peak on the baseline above the endothermic peak end point temperature, thereby calculating the endothermic amount at the endothermic peak having the peak top temperature of the endothermic peak.

[0080] <Number average molecular weight (Mn) and weight average molecular weight (Mw)> The number average molecular weight (Mn) and weight average molecular weight (Mw) were measured under the following conditions using a sample solution obtained by dissolving a polyester resin in tetrahydrofuran (THF) and filtering off the insoluble matter with a glass filter. Equipment: Tosoh Corporation HLC-8120 Column: TSK GEL GMH6 (2 columns) (Tosoh Corporation) Measurement temperature: 40℃ Sample solution: 0.25 wt% THF solution Solution injection volume: 100μl Detector: Refractive index detector Standard substance: 12 standard polystyrenes (TSK standard 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)

[0081] <Acid value and hydroxyl value> Measurement was performed according to the method specified in JIS K0070, except that the solvent used for measuring the acid value was a mixed solvent of acetone, methanol, and toluene (acetone:methanol:toluene=12.5:12.5:75), and the solvent used for measuring the hydroxyl value was THF.

[0082] <1 / 2 temperature drop> Using a constant test force extrusion-type capillary rheometer flow tester (Shimadzu Corporation, CFT-500D), 1 g of a test sample was heated at a heating rate of 6°C / min while applying a load of 1.96 MPa with the plunger, and the sample was extruded from a nozzle 1 mm in diameter and 1 mm in length. A graph of "plunger depression (flow value)" versus "temperature" was plotted, and the temperature corresponding to half the maximum plunger depression was read from the graph. This value (the temperature at which half of the test sample had flowed out) was taken as the half-depression temperature.

[0083] <Method for measuring glass transition temperature (Tg)> Measurement was carried out using a differential scanning calorimeter (DSC Q20, manufactured by TA Instruments) according to the method (DSC method) specified in ASTM D3418-82 under the following 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) Keep at -35°C for 10 minutes (5) Heat up to 150°C at 20°C / min (6) The differential scanning calorimetric curve measured in the process of (5) was analyzed to determine the glass transition temperature.

[0084] <Volume average particle size (D50) (μm), number average particle size (μm), particle size distribution (volume average particle size / number average particle size) of toner> Measurement was carried out using a Coulter counter [trade name: Multisizer III (manufactured by Beckman Coulter, Inc.)]. First, 0.1 to 5 mL of a surfactant (alkylbenzene sulfonate) was added as a dispersant to 100 to 150 mL of ISOTON-II (Beckman Coulter) electrolyte solution. 2 to 20 mg of the sample was then added, and the suspended electrolyte was dispersed in an ultrasonic disperser for approximately 1 to 3 minutes. The toner volume and particle count were measured using a 50 μm aperture on the measuring device, and the volume and number distributions were calculated. From the resulting distributions, the toner's volume average particle diameter (D50) (μm), number average particle diameter (μm), and particle size distribution (volume average particle diameter / number average particle diameter) were determined.

[0085] <Production Example 1> [Synthesis of Crystalline Polyester (A-1)] A reactor equipped with a condenser, heating / cooling device, thermometer, stirrer, and nitrogen inlet tube was charged with 591 parts (50.0 mol%) of 1,10-decanediol, 520 parts (50.0 mol%) of terephthalic acid, and 1.5 parts of titanium dihydroxybis(triethanolamine) as a condensation catalyst. The mixture was reacted at 170°C under a nitrogen stream for 8 hours while distilling off the water produced. The temperature was then gradually increased to 220°C, and the mixture was reacted under a nitrogen stream for 4 hours while distilling off the water produced. The mixture was then further reacted under a reduced pressure of 0.5 to 2.5 kPa, and the mixture was removed when the acid value reached 0.3 mg KOH / g. The removed resin was cooled to room temperature and pulverized to obtain crystalline polyester (A-1). The crystalline polyester (A-1) had a number average molecular weight (Mn) of 4,000, a weight average molecular weight (Mw) of 11,000, a peak top temperature (Tm) of the endothermic peak of 128°C, an endothermic amount at the endothermic peak of 40 J / g, an acid value of 0.3 mg KOH / g, and a hydroxyl value of 8.2 mg KOH / g.

[0086] <Production Example 2> [Synthesis of Crystalline Polyester (A-2)] Crystalline polyester (A-2) was obtained in the same manner as in Production Example 1, except that the raw materials listed in Table 1 were used. Table 1 shows the number average molecular weight (Mn), weight average molecular weight (Mw), peak top temperature (Tm) of the endothermic peak, endothermic amount at the endothermic peak, acid value, and hydroxyl value of the obtained crystalline polyester.

[0087] The compositions and resin properties of the crystalline polyesters (A) obtained in Production Examples 1 and 2 are shown in Table 1.

[0088] [Table 1]

[0089] <Production Example 3> [Synthesis of amorphous polyester (B-1)] A reactor equipped with a condenser, stirrer, and nitrogen inlet was charged with 193 parts (14.6 mol%) of bisphenol A·PO 2-mol adduct (Sanyo Chemical Industries, Ltd., "Hymer BP-2P"), 539 parts (35.4 mol%) of bisphenol A·PO 3-mol adduct (Sanyo Chemical Industries, Ltd., "Hymer BP-3P"), 173 parts (26.7 mol%) of terephthalic acid, 67 parts (11.8 mol%) of adipic acid, 86 parts (11.5 mol%) of trimellitic anhydride, and 3.6 parts of titanium dihydroxybis(triethanolamine) as a condensation catalyst. The mixture was reacted at 220 °C for 20 hours while distilling off the resulting water. The reaction was continued under reduced pressure of 0.5 to 2.5 kPa until the temperature reached 150 °C, at which point the mixture was removed using a steel belt cooler. The removed resin was pulverized into particles to obtain amorphous polyester (B-1). The amorphous polyester (B-1) had a 1 / 2 drop temperature of 150°C, a glass transition temperature Tg of 60°C, an acid value of 23 mgKOH / g, a hydroxyl value of 1 mgKOH / g, and a weight average molecular weight Mw of 130,000.

[0090] <Production Example 4> [Synthesis of amorphous polyester (B-2)] In a separate reaction vessel equipped with a condenser, stirrer, and nitrogen inlet, 324 parts (20.0 mol%) of bisphenol A·PO 2-mol adduct (Sanyo Chemical Industries, Ltd., "Hymer BP-2P"), 443 parts (30.0 mol%) of bisphenol A·EO 2-mol adduct (Sanyo Chemical Industries, Ltd., "Hymer BPE-20"), 280 parts (47.7 mol%) of terephthalic acid, and 3.0 parts of titanium dihydroxybis(triethanolamine) as a condensation catalyst were added. The mixture was heated to 230 °C under reduced pressure of 0.5 to 2.5 kPa while distilling off the water produced, and the reaction was continued until the acid value reached less than 2 mg KOH / g. The mixture was then cooled to 180 °C, and 14 parts (2.3 mol%) of trimellitic anhydride was added. The mixture was allowed to react under normal pressure for 1 hour and then discharged. The discharged resin was cooled to room temperature and pulverized to obtain amorphous polyester (B-2). The amorphous polyester (B-2) had a half drop temperature of 97°C, a glass transition temperature (Tg) of 58°C, an acid value of 8 mgKOH / g, a hydroxyl value of 55 mgKOH / g, and a weight average molecular weight (Mw) of 5,000.

[0091] <Examples 1 and 2 and Comparative Examples 1 and 2> <Evaluation of dispersibility of crystalline polyester (A) in amorphous polyester (B)> (1) Toner binder manufacturing 10 parts of each of the crystalline polyesters (A-1) to (A-2) were premixed with 27 parts of the amorphous polyester (B-1) and 63 parts of the amorphous polyester (B-2) using a Henschel mixer [FM10B manufactured by Mitsui Miike Chemical Engineering Co., Ltd.], and then kneaded in a twin-screw kneader [IMC-9B20 manufactured by Imoto Machinery Co., Ltd.] at the temperature and for the residence time shown in Table 2 to obtain a toner binder. (2) Creation and evaluation of evaluation samples The resulting toner binder was embedded in a visible-light-curable embedding resin (D-800, Nissin EM Co., Ltd.), cut into 60-nm-thick sections using an ultrasonic ultramicrotome (EM5, Leica), and then stained with ruthenium using a vacuum staining device (Filgen). The dispersion state of the crystalline polyester in the amorphous polyester was then observed from a cross-section of the resulting mixture using a transmission electron microscope (H7500, Hitachi High-Technologies Corporation) at an accelerating voltage of 120 kV (Figures 1 to 8). The longest diameter of the crystalline polyester in the entire observed image was taken as the maximum particle size. Randomly selected enlarged images (×1000) were processed using the free software "Image J" using the following procedure, and the calculated "mean particle size" was used as the average particle size of the crystalline polyester. 1.Image type → 8bit 2.line → analyze → set scale → known distance 5.0 3.process → binary → median filter 10 4.image → adjust → threshold 5.process → binary → fill holl 6.Analyze particles (set mesearements → feret diameter)

[0092] <Evaluation of low-temperature fixability, chargeability, heat-resistant storage stability and fixation strength of toner> (3) Toner manufacturing To 10 parts of each of the crystalline polyesters (A-1) to (A-2), 27 parts of the amorphous polyester (B-1), and 63 parts of the amorphous polyester (B-2), 8 parts of the pigment carbon black "MA-100" [manufactured by Mitsubishi Chemical Corporation] as a colorant, 4 parts of the paraffin wax "HNP-9" [manufactured by Nippon Seiro Co., Ltd.] as a mold release agent, and 1 part by weight of the charge control agent "T-77" [manufactured by Hodogaya Chemical Co., Ltd.] were added, and the mixture was premixed using a Henschel mixer [manufactured by Mitsui Miike Chemical Engineering Co., Ltd., FM10B], and then kneaded in a twin-screw kneader [manufactured by Imoto Machinery Co., Ltd., IMC-9B20] at the temperature and residence time shown in Table 2. The resin particles were then finely pulverized using a supersonic jet mill, Labojet (manufactured by Nippon Pneumatic Mfg. Co., Ltd.), and classified using an air classifier (MDS-I, manufactured by Nippon Pneumatic Mfg. Co., Ltd.) to obtain resin particles with a volume average particle size of 5 μm and a particle size distribution of 1.2. The resulting resin particles (99 parts) were mixed with 1 part of a flow agent, hydrophobic silica "Aerosil R972" (manufactured by Nippon Aerosil) in a sample mill to obtain a toner.

[0093] (4) Toner evaluation <Low temperature fixability (MFT)> Toner is applied to the paper at 0.6 mg / cm 2 The powder was evenly applied to the paper surface using a printer with the heat fixing unit removed. Other methods may be used as long as the powder can be evenly applied at the above weight density. The paper was then placed on a pressure roller at a fixing speed (heat roller peripheral speed) of 213 mm / sec and a fixing pressure (pressure roller pressure) of 10 kg / cm. 2 Under these conditions, the heating roller temperature was changed in 5°C increments over a range from 90 to 230°C, and fixed images were created at each temperature. Next, the presence or absence of cold offset in each fixed image was visually confirmed in ascending order of heating roller temperature, and the temperature at which cold offset no longer occurred is shown in Table 2 as MFT (°C). The lower the temperature at which cold offset does not occur, the better the low-temperature fixability. Under these evaluation conditions, the MFT is generally preferably 125° C. or less.

[0094] <Chargeability> (charge amount) 0.5g of toner and 10g of ferrite carrier (F-150, manufactured by Powder Tech Co., Ltd.) were placed in a 50ml glass bottle, which was then conditioned for 8 hours at 23°C and 50% relative humidity. The glass bottle containing the conditioned toner was sealed and placed in a Turbula shaker mixer for 2 minutes of friction stirring at 90 rpm. After stirring, 0.2g of the mixed powder was loaded into a blow-off powder charge measurement device equipped with a 20µm stainless steel mesh. The charge of the remaining ferrite carrier was measured under conditions of a blow pressure of 10KPa and a suction pressure of 5KPa, and the charge of the toner (µC / g) was calculated using a standard method. For toner, the higher the negative charge amount, the better the charging characteristics, and it is preferable that the negative charge amount is -15 μC / g or less. The charge amount was measured using a blow-off charge amount measuring device (manufactured by Toshiba Chemical Co., Ltd.).

[0095] <Heat-resistant storage stability> (degree of agglomeration) 1 g of toner and 0.013 g of Aerosil R8200 (manufactured by Evonik Japan Co., Ltd.) were mixed in a shaker for 1 hour, the mixture was placed in an airtight container, and left to stand for 48 hours in an atmosphere of 45°C and 80% humidity. The degree of cohesion was measured using a powder tester, and the heat-resistant storage stability was evaluated. The lower the value in the cohesion test determined by the following method, the better the heat-resistant storage stability. Under these evaluation conditions, a value of 3% or less is preferred. Equipment: Powder Tester model PT-X (manufactured by Hosokawa Micron) Sieve openings: 355μm, 250μm, 150μm Vibration width: 1mm Vibration duration: 30 seconds Operation method: Place sieves on the vibration table of the powder tester in the following order: top 355μm, middle 250μm, bottom 150μm. Place 1g of toner on the top sieve and vibrate at a vibration amplitude of 1mm for 30 seconds, then measure the weight of toner remaining on each sieve. Cohesion: Calculated from the weight of the toner used for measurement and the weight of the toner remaining after sieving. Cohesion degree (%)=(U / N+M / N×3 / 5+L / N×1 / 5)×100 U: Weight of the top row, M: Weight of the middle row, L: Weight of the bottom row, N: Weight of the sample (1g)

[0096] <Fixing strength> (Tape peeling) The fixing strength of the fixed image in the MFT prepared for the evaluation of low-temperature adhesion was evaluated by a tape peeling test. Tape (3M's "Scotch Mending Tape") was applied to the fixed image, and then the tape was peeled off. The image density (ID) of the image attached to the tape was measured using a reflection densitometer (trade name "X-Rite Model 404", manufactured by X-Rite). The smaller the image density (numerical value) of the attached image, the higher the fixing strength. Under these evaluation conditions, a value of 0.2 or less is preferred.

[0097] <Fixing strength> (pencil hardness) The MFT-fixed image prepared in the evaluation of low-temperature adhesion was subjected to a scratch hardness test in accordance with JIS K5600-5-4 (1999) by manually scratching the image with a pencil fixed at a 45-degree angle, applying a load of 10 g from directly above. The image strength was evaluated based on the pencil hardness at which the image was not scratched. The higher the pencil hardness, the better the image strength. Generally, a pencil hardness of HB or higher is preferable.

[0098] [Table 2]

[0099] As is clear from the results in Table 2 and Figures 1 to 8, the toner binders of Examples 1 and 2 have smaller maximum particle diameters of the crystalline polyester in the amorphous polyester, smaller average particle diameters, and better dispersibility than those of Comparative Examples 1 and 2, and further have higher charge amounts, heat-resistant storage stability, and fixing strength. [Industrial Applicability]

[0100] The toner binder of the present invention can be suitably used as a toner binder for electrophotographic toners used for developing latent images formed in electrophotography, electrostatic recording, electrostatic printing, and the like. Furthermore, it is suitable for use as an additive for paints, an additive for adhesives, particles for electronic paper, and the like.

Claims

1. A method for producing a toner binder containing a crystalline polyester (A) and an amorphous polyester (B), wherein the crystalline polyester (A) is a crystalline polyester containing 60 to 100 mol % in total of an aliphatic diol having 2 to 24 carbon atoms and terephthalic acid, based on the total molar number of raw material monomers of (A), the crystalline polyester (A) has an endothermic peak-top temperature (Tm) of 120 to 130°C as measured by a differential scanning calorimeter (DSC), and the method includes a step (1) of kneading the crystalline polyester (A) and the amorphous polyester (B) at a temperature equal to or lower than the endothermic peak-top temperature (Tm) of the crystalline polyester (A), and the difference (Tm - Tk) between the temperature (Tk) at which the crystalline polyester (A) and the amorphous polyester (B) are kneaded in the step (1) and the endothermic peak-top temperature (Tm) of the crystalline polyester (A) is 10 to 50°C.

2. 2. The method for producing a toner binder according to claim 1, wherein the weight ratio (A / B) of the crystalline polyester (A) to the amorphous polyester (B) is 5 / 95 to 20 / 80.

3. 2. The method for producing a toner binder according to claim 1, wherein the weight average molecular weight of the amorphous polyester (B) is 2,000 to 20,000.

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