JP7227828B2 - Toner for electrostatic charge image development - Google Patents

Description

The present invention relates to a toner for electrostatic charge image development.

In the field of electrophotography, with the development of electrophotographic systems, there is a demand for the development of electrophotographic toners capable of achieving higher image quality and higher speed. As a method of obtaining a toner with a narrow particle size distribution and a small particle size corresponding to high image quality, the aggregation fusion method (emulsification So-called chemical toner is produced by agglomeration method, aggregation coalescence method).
Recently, copiers, multi-function machines, and printers using electrophotographic systems have been remarkably increased in speed, and therefore toners are required to have hot offset resistance in addition to low-temperature fixability. In order to cope with this, a toner using a polyester excellent in low-temperature fixability as a toner binder has been proposed.

Patent Document 1 describes a liquid developer having toner particles containing a polymer having an active hydrogen group and a polymer having a blocked isocyanate group, and a carrier liquid, and has low-temperature fixability and high fixing strength. It is shown that high toner images can be obtained.
In Patent Document 2, it is produced from at least a binder resin and a colorant in an aqueous medium, 50% by weight or more and less than 100% by weight of the binder resin is a polyester resin, and the binder resin contains a blocked isocyanate compound. It is disclosed that the toner for developing an electrostatic charge image is characterized by having excellent low-temperature fixability and that it is possible to suppress toner elution from the cleaning roller.

JP 2017-67861 A JP-A-2006-47898

However, although toners using polyester are excellent in low-temperature fixability, they have problems such as insufficient hot offset resistance and low image fastness after fixing. On the other hand, when the elasticity of the polyester is increased in advance by adding a crosslinking agent or the like, the low-temperature fixability deteriorates. Therefore, it has been required to have excellent low-temperature fixability, excellent hot-offset resistance, and improved fastness of the image after fixing.
TECHNICAL FIELD The present invention relates to a toner excellent in low-temperature fixability, excellent in hot offset resistance, and excellent in image fastness after fixing, and a method for producing the same.

The present inventors paid attention to a method for improving the elasticity of toner in the fixing process. As a result, the inventors have found that adding a specific blocked isocyanate compound in which the isocyanate group is blocked to the toner is effective.
The present invention relates to the following [1] and [2].
[1] Containing a polyester resin and a blocked isocyanate compound, the polyester resin having a structural unit derived from a polyol and a structural unit derived from a polycarboxylic acid, and a structure derived from the polycarboxylic acid The unit contains a structural unit derived from a trivalent or higher carboxylic acid, the hydroxyl value of the polyester resin is 5 mgKOH/g or more, and the blocked isocyanate compound is an adduct-type blocked isocyanate compound. Toner for electrostatic charge image development.
[2] A step of aggregating resin particles containing a polyester resin and a blocked isocyanate compound to obtain aggregated particles, and a step of fusing the aggregated particles, wherein the polyester resin is derived from a polyol. and a structural unit derived from a polycarboxylic acid, wherein the structural unit derived from the polycarboxylic acid contains a structural unit derived from a trivalent or higher carboxylic acid, and the hydroxyl value of the polyester resin is 5 mg KOH/g or more, the blocked isocyanate compound is an adduct-type blocked isocyanate compound, and in all steps after the addition of the blocked isocyanate compound, at a dissociation temperature of the blocking agent of the blocked isocyanate compound or less. A method for producing a toner for developing an electrostatic charge image.

According to the present invention, it is possible to provide a toner having excellent low-temperature fixability, excellent hot offset resistance, and excellent image fastness after fixing, and a method for producing the same.

[Electrostatic Image Developing Toner and Production Method Thereof]
The toner for developing an electrostatic charge image of the present invention (hereinafter also simply referred to as "toner") contains a polyester resin and a blocked isocyanate compound, and the polyester resin comprises structural units derived from a polyol and a polycarboxylic acid The structural unit derived from the polycarboxylic acid contains a structural unit derived from a trivalent or higher carboxylic acid, and the hydroxyl value of the polyester resin is 5 mgKOH / g or more. , the blocked isocyanate compound is an adduct-type blocked isocyanate compound.
According to the present invention, it is possible to obtain a toner having excellent low-temperature fixability, excellent hot offset resistance, and excellent image fastness after fixing.

As described above, toners using polyester-based resins have excellent low-temperature fixability, but have problems of insufficient hot offset resistance and image fastness after fixing. In order to obtain image fastness after fixing, it is effective to add a crosslinking agent or the like to increase the crosslinking strength of the binder resin and increase the elasticity of the toner. However, when the elasticity of the toner is increased in advance, although the image fastness after fixing is obtained, there is a problem that the low-temperature fixability is deteriorated.
The present inventors have found that by using a toner in which the polyester resin has a high molecular weight due to the heat received by the toner in the fixing process, it has excellent low-temperature fixability, excellent hot offset resistance, and the durability of the obtained image. It has been found that the property can be enhanced.
Although the detailed mechanism by which the addition of a specific blocked isocyanate compound provides excellent low-temperature fixability, excellent hot-offset resistance, and improved image fastness after fixing is not completely clear, the following points are possible. can be considered. A blocked isocyanate compound is a compound in which the blocking agent is dissociated at a certain temperature or higher, and the isocyanate group reacts. By producing the toner at a temperature at which the blocking agent for the blocked isocyanate compound does not dissociate, the toner containing the blocked isocyanate can be obtained. When this blocked isocyanate compound is present in the toner, when the toner is melted by heating during fixing, the polyester-based resin that is the toner binder melts, and furthermore, the blocking agent of the blocked isocyanate compound is dissociated, and the isocyanate group is dissolved. expose. Then, the hydroxyl groups (OH groups) and isocyanate groups of the polyester resin, which is the melted toner binder, react with each other to crosslink the polyester resin and increase the molecular weight of the polyester resin. It is considered that the toner has excellent low-temperature fixability, excellent anti-offset property, and high fastness image can be obtained.
Furthermore, as this blocked isocyanate compound, an adduct-type blocked isocyanate compound is particularly useful. Since the heat received when the toner is fixed is smaller for toners with excellent low-temperature fixability, a polyisocyanate with a structure similar to a simple diisocyanate will not sufficiently react with hydroxyl groups due to the heat received during fixing. It is considered that sufficient high elasticity does not progress. In addition to the adduct type, the isocyanurate type and the biuret type are also known as blocked isocyanate trimers. It is considered that the reason why it is useful is that the bond-forming reaction with the polyester-based resin is likely to occur even with the short-time heat received during heating.
Furthermore, when the polyester-based resin has a structural unit derived from a trivalent or higher carboxylic acid, a branched structure is introduced into the polyester-based resin, and when a crosslinked structure is formed, a structure with more excellent elasticity is obtained. Conceivable.

Definitions of various terms used in this specification are shown below.
In the specification, the carboxylic acid component of the polyester resin includes not only the compound but also an anhydride that decomposes during the reaction to generate a carboxylic acid, and an alkyl ester of each carboxylic acid (an alkyl group having 1 to 3 carbon atoms below) are also included.
"Volume-median particle size ( _D50 )" is a particle size at which the cumulative volume frequency calculated as a volume fraction is 50%, calculated from the smaller particle size.
The coefficient of variation of particle size distribution (hereinafter also simply referred to as “CV value”) is a value represented by the following formula. The volume average particle size in the following formula is the particle size obtained by multiplying the particle size measured on a volume basis by the ratio of particles having that particle size value, and dividing the resulting value by the number of particles. be.
CV value (%) = [standard deviation of particle size distribution (μm)/volume average particle size (μm)] × 100

A method for producing a toner according to an embodiment of the present invention includes, for example, a step of aggregating resin particles containing a polyester resin and a blocked isocyanate compound to obtain aggregated particles (hereinafter also referred to as “step 1”); It has a step of fusing aggregated particles (hereinafter also referred to as “step 2”) in this order.
The polyester-based resin has a structural unit derived from a polyol and a structural unit derived from a polycarboxylic acid, and the structural unit derived from the polycarboxylic acid contains a structural unit derived from a trivalent or higher carboxylic acid. do. Moreover, the hydroxyl value of the polyester resin is 5 mgKOH/g or more.
Furthermore, the blocked isocyanate is an adduct-type blocked isocyanate, and is produced at a temperature not higher than the dissociation temperature of the blocking agent of the blocked isocyanate in all steps after the addition of the blocked isocyanate.
That is, the electrostatic charge image developing toner of the present invention is preferably produced by the above method, and each component such as the polyester resin and the blocked isocyanate compound is common.
The present invention will be described below by taking the embodiment as an example.

<Step 1>
[Resin particle dispersion]
The resin particles used in step 1 (hereinafter also referred to as "resin particles X") contain a polyester resin and a blocked isocyanate compound.
The polyester-based resin contains a structural unit derived from a carboxylic acid having a valence of 3 or more. Moreover, the hydroxyl value of the polyester resin is 5 mgKOH/g or more. Hereinafter, the polyester resin used in the toner of the present invention, which contains a structural unit derived from a trivalent or higher carboxylic acid and has a hydroxyl value of 5 mgKOH/g or more, is also referred to as "polyester resin A."
The polyester-based resin A is, for example, a polyester resin that is a polycondensate of an alcohol component and a carboxylic acid component.
Examples of the polyester-based resin A include polyester resins and modified polyester resins. Modified polyester resins include, for example, urethane-modified polyester resins, epoxy-modified polyester resins, and composite resins containing polyester resin segments and addition polymerized resin segments. Among these, polyester resins, which are polycondensates of alcohol components and carboxylic acid components, are preferred.

Examples of the alcohol component include alkylene oxide adducts of aromatic diols, linear or branched aliphatic diols, alicyclic diols, and trihydric or higher polyhydric alcohols. Among these, alkylene oxide adducts of aromatic diols are preferable from the viewpoint of obtaining a toner excellent in low-temperature fixability.
The alkylene oxide adduct of an aromatic diol is preferably an alkylene oxide adduct of bisphenol A, more preferably of formula (I):

（式中、ＯＲ^１及びＲ^２Ｏはオキシアルキレン基であり、Ｒ^１及びＲ^２はそれぞれ独立にエチレン基又はプロピレン基であり、ｘ及びｙはアルキレンオキシドの平均付加モル数を示し、それぞれ正の数であり、ｘとｙの和の値は、１以上、好ましくは１．５以上であり、１６以下、好ましくは８以下、より好ましくは４以下である）で表されるビスフェノールＡのアルキレンオキシド付加物である。

(Wherein, OR ¹ and R ² O are oxyalkylene groups, R ¹ and R ² are each independently an ethylene group or a propylene group, x and y represent the average number of moles of alkylene oxide added, each positive and the sum of x and y is 1 or more, preferably 1.5 or more, and 16 or less, preferably 8 or less, more preferably 4 or less). It is an oxide adduct.

Alkylene oxide adducts of bisphenol A include, for example, propylene oxide adducts of bisphenol A (2,2-bis(4-hydroxyphenyl)propane) and ethylene oxide adducts of bisphenol A. These may use 1 type(s) or 2 or more types.
In the present invention, the ratio of the structural units derived from the ethylene oxide adduct of bisphenol A to the total of the structural units derived from the propylene oxide adduct of bisphenol A and the structural units derived from the ethylene oxide adduct of bisphenol A is the isocyanate group. From the viewpoint of reactivity with, it is preferably 50 mol% or more, more preferably 70 mol% or more, still more preferably 90 mol% or more, and 100 mol% or less, still more preferably 100 mol%.
The content of the alkylene oxide adduct of bisphenol A in the alcohol component is preferably 70 mol% or more, more preferably 90 mol% or more, still more preferably 95 mol% or more, and 100 mol% or less, Even more preferably, it is 100 mol %.

Examples of linear or branched aliphatic diols include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol and 1,4-butanediol. , 2,3-butanediol, 2,2-dimethyl-1,3-propanediol (alias: neopentyl glycol), 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, 1 ,10-decanediol, 1,12-dodecanediol, 1,13-tridecanediol, and 1,14-tetradecanediol.
Examples of alicyclic diols include hydrogenated bisphenol A (2,2-bis(4-hydroxycyclohexyl)propane), alkylene oxide adducts having 2 to 4 carbon atoms of hydrogenated bisphenol A (average number of moles added: 2 above and below 12).
Other diol components include, for example, 1,2-propylene glycol.
Examples of trihydric or higher polyhydric alcohols include glycerin, pentaerythritol, trimethylolpropane, and sorbitol.
One or more of these alcohol components may be used.

Examples of the carboxylic acid component include dicarboxylic acids and polycarboxylic acids having a valence of 3 or more.
Dicarboxylic acids include, for example, aromatic dicarboxylic acids, linear or branched aliphatic dicarboxylic acids, and alicyclic dicarboxylic acids. Among these, at least one selected from aromatic dicarboxylic acids and linear or branched aliphatic dicarboxylic acids is preferred.
Examples of aromatic dicarboxylic acids include phthalic acid, isophthalic acid, and terephthalic acid. Among these, isophthalic acid and terephthalic acid are preferred, and terephthalic acid is more preferred.
The amount of the aromatic dicarboxylic acid in the carboxylic acid component is preferably 20 mol% or more, more preferably 30 mol% or more, still more preferably 40 mol% or more, still more preferably 50 mol% or more, and preferably It is 90 mol % or less, more preferably 85 mol % or less, still more preferably 80 mol % or less.

The number of carbon atoms in the linear or branched aliphatic dicarboxylic acid is preferably 2 or more, more preferably 3 or more, and preferably 30 or less, more preferably 20 or less.
Linear or branched aliphatic dicarboxylic acids include, for example, oxalic acid, malonic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, succinic acid, adipic acid, sebacic acid, dodecanedioic acid, tetradecanedioic acid, acid, azelaic acid, and succinic acid substituted with an aliphatic hydrocarbon group having 1 to 20 carbon atoms. Examples of the succinic acid substituted with an aliphatic hydrocarbon group having 1 to 20 carbon atoms include dodecylsuccinic acid, dodecenylsuccinic acid, and octenylsuccinic acid. Among these, fumaric acid, sebacic acid, and succinic acid substituted with an aliphatic hydrocarbon group having 1 to 20 carbon atoms are preferred.
The amount of linear or branched aliphatic dicarboxylic acid in the carboxylic acid component is preferably 1 mol% or more, more preferably 3 mol% or more, still more preferably 5 mol% or more, and preferably 80 mol%. Below, more preferably 50 mol % or less, still more preferably 30 mol % or less.

The trivalent or higher polyvalent carboxylic acid is preferably a trivalent carboxylic acid, such as trimellitic acid. Preferred is trimellitic acid or its anhydride.
In the present invention, structural units derived from carboxylic acids have structural units derived from trivalent or higher carboxylic acids. By having a structural unit derived from a trivalent or higher carboxylic acid, it is possible to introduce a branched chain into the polyester resin, and when a crosslinked structure is formed by the reaction with the blocked isocyanate compound, the elasticity is more excellent. A structure is obtained, and an image having excellent fastness is obtained.
The amount of trivalent or higher polycarboxylic acid is preferably 3 mol% or more, more preferably 5 mol% or more, still more preferably 8 mol% or more, and preferably 30 mol% or less in the carboxylic acid component. , more preferably 25 mol % or less, still more preferably 20 mol % or less, and even more preferably 15 mol % or less.
One or more of these carboxylic acid components may be used.

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

Polyester-based resin A may be produced, for example, by a method including step A of polycondensing an alcohol component and a carboxylic acid component.
In step A, an esterification catalyst such as di(2-ethylhexanoic acid)tin (II), dibutyltin oxide, titanium diisopropylate bistriethanolamine, etc. is added to the alcohol component and the carboxylic acid component in a total amount of 100, if necessary. 0.01 parts by mass or more and 5 parts by mass or less per part by mass; Esterification promoter such as gallic acid (same as 3,4,5-trihydroxybenzoic acid), total amount of alcohol component and carboxylic acid component is 100 mass 0.001 parts by mass or more and 0.5 parts by mass or less may be used for polycondensation.
Further, when a monomer having an unsaturated bond such as fumaric acid is used for polycondensation, it is preferably 0.001 part by mass or more with respect to 100 parts by mass as the total amount of the alcohol component and the carboxylic acid component, if necessary. A radical polymerization inhibitor of 0.5 parts by mass or less may be used. Examples of radical polymerization inhibitors include 4-tert-butylcatechol.
The temperature of the polycondensation reaction is preferably 120° C. or higher, more preferably 160° C. or higher, still more preferably 180° C. or higher, and preferably 250° C. or lower, more preferably 240° C. or lower. In addition, you may perform polycondensation in an inert gas atmosphere.

<<Physical properties of polyester resin A>>
The softening point of the polyester resin A is preferably 70° C. or higher, more preferably 90° C. or higher, and still more preferably 100° C. or higher. It is preferably 140° C. or lower, more preferably 125° C. or lower.
The glass transition temperature of polyester resin A is preferably 30° C. or higher, more preferably 35° C. or higher, and still more preferably 40° C. or higher. It is more preferably 70° C. or lower, still more preferably 65° C. or lower.

The hydroxyl value of the polyester resin A is preferably 5 mgKOH/g or more, more preferably 10 mgKOH/g or more, still more preferably 15 mgKOH, from the viewpoint of reactivity with the blocked isocyanate compound in which the blocking agent is dissociated (deprotected). /g, and preferably 50 mgKOH/g, more preferably 45 mgKOH/g or less, even more preferably 40 mgKOH/g or less, and even more preferably 35 mgKOH/g or less.
The acid value of polyester resin A is preferably 5 mgKOH/g or more, more preferably 10 mgKOH/g or more, still more preferably 15 mgKOH/g or more, and preferably 40 mgKOH/g or less, more preferably 35 mgKOH/g or less. and more preferably 30 mgKOH/g or less.
The softening point, glass transition temperature, hydroxyl value, and acid value of the polyester resin A can be appropriately adjusted depending on the type and amount of raw material monomer used, and the production conditions such as the reaction temperature, reaction time, and cooling rate. Moreover, those values are determined by the method described in Examples.
When two or more polyester resins A are used in combination, the softening point, glass transition temperature, hydroxyl value, and acid value of the mixture are preferably within the ranges described above.

In the present invention, as the polyester resin, two or more polyester resins may be used in combination, and in addition to the polyester resin A, for example, it has a structural unit derived from a trivalent or higher carboxylic acid. It is not particularly limited and may be used in combination with a polyester resin that does not contain any. Further, as the binder resin, in addition to the polyester-based resin, other resin such as an addition polymerization resin may be contained.
The content of the polyester-based resin A is preferably 40% by mass or more, more preferably 50% by mass or more, still more preferably 60% by mass or more, and even more preferably, based on the total amount of the resin components of the resin particles X. is 70% by mass or more, more preferably 90% by mass or more, and is 100% by mass or less, and may be 100% by mass.

(Blocked isocyanate compound)
A blocked isocyanate compound is a polyisocyanate compound such as a diisocyanate compound in which the isocyanate groups are protected with a thermally dissociable blocking agent. In the present invention, an adduct-type blocked isocyanate compound is used as the blocked isocyanate compound. As blocked isocyanates, there are various types of blocked isocyanates such as biuret type, isocyanurate type, adduct type, and bifunctional type. A toner having excellent hot offset property and excellent image fastness can be obtained.

An adduct-type polyisocyanate compound can be obtained, for example, by reacting a diisocyanate compound with a polyhydric alcohol having three or more hydroxyl groups.
The diisocyanate compound is not particularly limited as long as it is a compound having two isocyanate groups (also referred to as isocyanato groups). For example, the carboxyl groups of ethylene diisocyanate, tetramethylene diisocyanate, hexamethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, lysine diisocyanate, and dimer acid were converted to isocyanate groups. aliphatic diisocyanates such as dimer diisocyanate; and alicyclic diisocyanates such as 1,3-bis(isocyanatomethyl)cyclohexane; xylylene diisocyanate, 4,4'-diphenyl diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, m-phenylene Diisocyanate, p-phenylene diisocyanate, 4,4'-diphenylmethane diisocyanate, 4,4'-diphenyldimethylmethane diisocyanate, 4,4'-dibenzyl diisocyanate, dialkyldiphenylmethane diisocyanate, tetraalkyldiphenylmethane diisocyanate, 1,5-naphthylene diisocyanate , 3,3′-dimethyl-4,4′-biphenylene diisocyanate, polymethylene polyphenylene polyisocyanate, phenylene diisocyanate, and m-tetramethylxylylene diisocyanate; aliphatic diisocyanates, alicyclic diisocyanates , and a diisocyanate compound that is a dimer of at least one diisocyanate selected from the group consisting of aromatic diisocyanates and has a uretdione structure; aliphatic diisocyanates, alicyclic diisocyanates, and aromatic diisocyanates A diisocyanate compound having an allophanate structure using at least one diisocyanate selected from the group; and at least one diisocyanate selected from the group consisting of aliphatic diisocyanates, alicyclic diisocyanates, and aromatic diisocyanates and a diisocyanate compound having a urea structure.
Among these, hexamethylene diisocyanate, isophorone diisocyanate, xylylene diisocyanate, diphenylmethane diisocyanate, and tolylene diisocyanate are preferred from the viewpoint of reactivity and availability, and hexamethylene diisocyanate is more preferred.

Examples of polyhydric alcohols include glycerin, trimethylolpropane, pentaerythritol, diglycerin, dipentaerythritol, D-threitol, L-arabinitol, ribitol, xylitol, sorbitol, mannitol, galactitol, rhamnitol, arabinose, ribose, xylose, glucose, mannose, galactose, fructose, sorbose, rhamnose, fucose, ribodesose, trehalose, sucrose, maltose, cellobiose, gentiobiose, lactose, melibiose, raffinose, gentianose, melezitose, stachyose and the like. These may be used alone or in combination of two or more.
Among these, trimethylolpropane is preferable from the viewpoint of availability and reactivity.
As the polyisocyanate compound having an adduct structure, a reaction product of trimethylolpropane and hexamethylene diisocyanate is particularly preferred.

The blocking agent is not particularly limited as long as it is thermally dissociable and generally used. Alcohol types such as ethanol, 2-propanol, n-butanol, sec-butanol, 2-ethyl-1-hexanol, 2-methoxyethanol, 2-ethoxyethanol, 2-butoxyethanol; acetanilide, acetic acid amide, ε-caprolactam, Acid amide type such as δ-valerolactam and γ-butyrolactam; Acid imide type such as succinimide and maleic acid imide; Phenol, cresol, ethylphenol, butylphenol, nonylphenol, dinonylphenol, styrenated phenol, hydroxybenzoic acid ester phenol type of; amine type such as diphenylamine, aniline, carbazole, di-n-propylamine, diisopropylamine, isopropylethylamine; active methylene type such as dimethyl malonate, diethyl malonate, methyl acetoacetate, ethyl acetoacetate, acetylacetone; imidazole type such as imidazole and 2-methylimidazole; pyrazole type such as pyrazole, 3-methylpyrazole and 3,5-dimethylpyrazole; These may be used alone or in combination of two or more.
Among these, in consideration of application to toners, low-temperature dissociating blocking agents are preferred, pyrazole-type and oxime-type blocking agents are more preferred, and 3,5-dimethylpyrazole (also simply referred to as dimethylpyrazole) and methyl ethyl ketone oxime are more preferred. .

The dissociation temperature of the blocking agent in the blocked isocyanate compound is selected from the viewpoint of suppressing the dissociation of the blocking agent during toner production, and promoting the dissociation of the blocking agent during fixing of the toner and reacting with the hydroxyl groups of the polyester resin to cause cross-linking. From the viewpoint of formation, the temperature is preferably 100° C. or higher, more preferably 105° C. or higher, still more preferably 110° C. or higher, and is preferably 160° C. or lower, more preferably 150° C. or lower, and still more preferably 140° C. or lower. .

As the blocked isocyanate compound, commercially available products may be used, specifically, Tosoh Co., Ltd., Coronate series; Showa Denko K.K., Karenz series; Asahi Kasei Corporation, Duranate series; Trixenxe series manufactured by Baxenden; Meikanate series manufactured by Meisei Chemical Industry; Vestagon series manufactured by Evonik; Elastron series manufactured by Daiichi Kogyo Seiyaku Co., Ltd.;

Regarding the amount of the blocked isocyanate compound in the resin particles, the ratio NCO/OH of the isocyanate group (NCO group) in the blocked isocyanate compound to the hydroxyl group (OH group) of the polyester resin is preferably 0.4 or more, and more. It is preferably 0.7 or more, more preferably 0.9 or more, and preferably 2.0 or less, more preferably 1.5 or less, and still more preferably 1.2 or less.

(Method for producing resin particle dispersion)
Resin particles X containing a polyester resin and a blocked isocyanate compound can be obtained by a known method such as a suspension method, a solvent phase inversion emulsification method, or a forced emulsification method. From the viewpoint of stably obtaining fine emulsified particles, it is preferably obtained by a solvent phase inversion emulsification method.
In the step of obtaining the resin particles X, the temperature is preferably lower than the temperature at which the blocking agent of the blocked isocyanate dissociates, preferably 95°C or lower, more preferably 80°C or lower, and even more preferably 75°C or lower. .
Examples of the phase inversion emulsification method include a method in which an aqueous medium is added to a resin solution in an organic solvent to perform phase inversion emulsification.

The organic solvent used for phase inversion emulsification is not particularly limited as long as it dissolves the resin, but from the viewpoint of facilitating phase inversion, for example, alcoholic solvents such as ethanol, isopropanol, and isobutanol; acetone, methyl ethyl ketone, and methyl isobutyl ketone. , diethyl ketone and the like; ether solvents such as dibutyl ether, tetrahydrofuran and dioxane; and acetate solvents such as ethyl acetate and isopropyl acetate. Among these, ketone-based solvents and acetic acid ester-based solvents are preferred, and methyl ethyl ketone, ethyl acetate, and isopropyl acetate are more preferred, from the viewpoint of ease of removal from the mixed solution after addition of the aqueous medium.
A neutralizing agent is preferably added to the organic solvent solution. Neutralizing agents include, for example, basic substances. Basic substances include, for example, alkali metal hydroxides such as sodium hydroxide and potassium hydroxide; and nitrogen-containing basic substances such as ammonia, trimethylamine and diethanolamine.
The use equivalent (mol%) of the neutralizing agent to the acid group of the polyester resin contained in the resin particles X is preferably 10 mol% or more from the viewpoint of obtaining fine resin particles and improving the dispersion stability. , more preferably 30 mol % or more, still more preferably 40 mol % or more, and preferably 90 mol % or less, more preferably 70 mol % or less.
The equivalent amount (mol%) of the neutralizing agent to be used can be determined by the following formula. The use equivalent of the neutralizing agent is synonymous with the degree of neutralization when it is 100 mol % or less.
Equivalent amount of neutralizing agent used (mol%) = [{added mass of neutralizing agent (g)/equivalent amount of neutralizing agent}/[{weighted average acid value of resin constituting resin particles X (mgKOH/g) x Mass (g) of resin constituting resin particles X}/(56×1000)]]×100

In the present invention, it is preferable to add the blocked isocyanate compound after dissolving the polyester resin in an organic solvent and, if necessary, neutralizing the solution.
From the viewpoint of suppressing the dissociation of the blocking agent from the blocked isocyanate compound, it is preferable to add the blocked isocyanate compound after neutralizing the polyester resin.
After adding the blocked isocyanate compound, it is preferable to sufficiently stir the mixture so that the blocked isocyanate is dissolved in the organic solvent.
In addition, in the present invention, in all the steps after adding the blocked isocyanate, the production is carried out at the dissociation temperature of the blocking agent of the blocked isocyanate compound or lower. As a result, the isocyanate group protected by the blocking agent is present in the toner, and the blocking agent dissociates when the toner is fixed, and functions as a cross-linking agent for the polyester resin contained in the toner, resulting in an image with superior fastness. is obtained.

Next, while stirring the organic solvent solution, an aqueous medium is gradually added to cause phase inversion.
From the viewpoint of improving the dispersion stability and suppressing the dissociation of the blocking agent from the blocked isocyanate compound, the temperature of the organic solvent solution during stirring and mixing when adding the aqueous medium and the temperature in the system after the addition of the aqueous medium are It is preferably 10°C or higher, more preferably 15°C, still more preferably 20°C or higher, and is preferably 90°C or lower, more preferably 85°C or lower, still more preferably 80°C or lower, and even more preferably 75°C or lower. is.

After the phase inversion emulsification, if necessary, the organic solvent may be removed from the resulting dispersion by distillation or the like.
The temperature in the system during distillation is preferably 30° C. or higher, more preferably 50° C. or higher, still more preferably 60° C. or higher, from the viewpoint of efficient removal of the organic solvent and suppression of dissociation of the blocking agent. More preferably 65° C. or higher, even more preferably 70° C. or higher, and preferably 90° C. or lower, more preferably 85° C. or lower, still more preferably 80° C. or lower, still more preferably 75° C. or lower.
In this case, the residual amount of the organic solvent in the dispersion is preferably 1% by mass or less, more preferably 0.5% by mass or less, and even more preferably substantially 0% by mass.

The volume-median particle size (D ₅₀ ) of the resin particles X in the dispersion is preferably 0.05 μm or more, more preferably 0.08 μm or more, from the viewpoint of obtaining a toner capable of obtaining high-quality images, and , preferably 0.8 μm or less, more preferably 0.4 μm or less, and still more preferably 0.3 μm or less.
The CV value of the resin particles X in the dispersion liquid is preferably 10% or more, more preferably 20% or more, and more preferably 40% or less, more preferably from the viewpoint of obtaining a toner capable of obtaining high-quality images. is 35% or less, more preferably 30% or less.
The volume-median particle size ( _D50 ) and CV value of the resin particles are obtained by the methods described in Examples below.

In step 1, together with the resin particles X, the colorant particles Z and the release agent particles W can be aggregated, if necessary.

[Colorant particle dispersion]
In step 1, together with resin particles X, colorant particles Z containing a colorant may be aggregated.
As the colorant, all dyes, pigments, etc. used as colorants for toners can be used.
Examples of colorants include carbon black, phthalocyanine blue, permanent brown FG, brilliant first scarlet, pigment green B, rhodamine-B base, solvent red 49, solvent red 146, solvent blue 35, quinacridone, carmine 6B, and disazo yellow. be done. The toner may be black toner or color toner other than black.

From the viewpoint of improving the image density of the toner, the content of the colorant is preferably 1 part by mass or more, more preferably 2 parts by mass or more, and still more preferably 5 parts by mass or more with respect to 100 parts by mass of the polyester resin. and preferably 40 parts by mass or less, more preferably 30 parts by mass or less, even more preferably 20 parts by mass or less, and even more preferably 10 parts by mass or less.

(Production of Dispersion of Colorant Particles)
The colorant is preferably mixed with the resin particles X as a dispersion liquid of the colorant particles Z and aggregated to be contained in the aggregated particles 1 .
The dispersion liquid of the colorant particles Z is preferably obtained by dispersing the colorant and the aqueous medium using a dispersing machine such as a homogenizer or an ultrasonic dispersing machine. From the viewpoint of improving the dispersion stability of the colorant, the dispersion is preferably carried out in the presence of a surfactant. Examples of the surfactant include nonionic surfactants, anionic surfactants, and cationic surfactants. From the viewpoint of improving the dispersion stability of the colorant particles Z, anionic surfactants are preferred. is an active agent. Anionic surfactants include, for example, dodecyl benzene sulfonate, dodecyl sulfate, lauryl ether sulfate, and alkenyl succinate. Among these, dodecylbenzenesulfonate is preferred.

From the viewpoint of improving the dispersion stability of the colorant, the content of the surfactant in the dispersion of the colorant particles Z is preferably 1 part by mass or more, more preferably 5 parts by mass with respect to 100 parts by mass of the colorant. parts or more, more preferably 10 parts by mass or more, and preferably 40 parts by mass or less, more preferably 30 parts by mass or less.

The volume median particle diameter (D ₅₀ ) of the colorant particles Z is preferably 0.05 μm or more, more preferably 0.08 μm or more, still more preferably 0.1 μm or more, and preferably 0.3 μm or less. More preferably, it is 0.2 μm or less.
The method for measuring the volume median particle size (D ₅₀ ) of the colorant particles Z is according to the method described in Examples.

[Releasing agent particle dispersion]
In step 1, together with resin particles X, release agent particles W containing a release agent may be aggregated.
Release agents include, for example, polypropylene wax, polyethylene wax, polypropylene polyethylene copolymer wax; hydrocarbon waxes such as microcrystalline wax, paraffin wax, Fischer-Tropsch wax, and Sasol wax; and oxides thereof; carnauba wax. , montan waxes or their deoxidized waxes, ester waxes such as fatty acid ester waxes; fatty acid amides, fatty acids, higher alcohols, and fatty acid metal salts. These may use 1 type(s) or 2 or more types.

The melting point of the releasing agent is preferably 60° C. or higher, more preferably 70° C. or higher, and preferably 160° C. or lower, more preferably 150° C. or lower, and still more preferably 140° C. or lower.
The content of the release agent in the toner is preferably 0.1% by mass or more, more preferably 1% by mass or more, still more preferably 3% by mass or more, and preferably 20% by mass or less, more preferably It is 15% by mass or less.

(Method for producing release agent particle dispersion)
It is preferable that the releasing agent is contained in the aggregated particles by mixing the releasing agent particles W as a dispersion with the resin particle dispersion and causing aggregation.
The dispersion of release agent particles W can be obtained using a surfactant, but is preferably obtained by mixing the release agent and resin particles P described later. By preparing the release agent particles W using the release agent and the resin particles P, the release agent particles W are stabilized by the resin particles P, and the release agent is added to the aqueous medium without using a surfactant. It can be dispersed in It is considered that the dispersion liquid of the release agent particles W has a structure in which a large number of resin particles P adhere to the surface of the release agent particles W.
The type and amount of release agent to be added are the same as those of the release agent described above.

The resin constituting the resin particles P in which the release agent is dispersed is preferably a polyester resin, and from the viewpoint of improving the dispersibility of the release agent in an aqueous medium, it has a polyester resin segment and an addition polymerized resin segment. Composite resin D is more preferably used.
As the alcohol component and the carboxylic acid component used in the polyester resin segment of the composite resin D, the alcohol component and the carboxylic acid component exemplified for the polyester resin A are exemplified.
Further, the addition polymerized resin segment of the composite resin D is, for example, an addition polymer of a raw material monomer containing a styrene compound.
Styrenic compounds include, for example, unsubstituted or substituted styrene. Examples of the substituent with which styrene is substituted include an alkyl group having 1 to 5 carbon atoms, a halogen atom, an alkoxy group having 1 to 5 carbon atoms, a sulfonic acid group, or a salt thereof.
Styrenic compounds include, for example, styrene, methylstyrene, α-methylstyrene, β-methylstyrene, tert-butylstyrene, chlorostyrene, chloromethylstyrene, methoxystyrene, styrenesulfonic acid and salts thereof. Among these, styrene is preferred.
The content of the styrenic compound in the raw material monomers of the addition polymerized resin segment is preferably 50% by mass or more, more preferably 65% by mass or more, still more preferably 75% by mass or more, and 100% by mass or less. , preferably 95% by mass or less, more preferably 90% by mass or less, and even more preferably 85% by mass or less.

Examples of raw material monomers other than styrene compounds include (meth)acrylic acid esters such as alkyl (meth)acrylate, benzyl (meth)acrylate, and dimethylaminoethyl (meth)acrylate; olefins; halovinyls such as vinyl chloride; vinyl esters such as vinyl acetate and vinyl propionate; vinyl ethers such as methyl vinyl ether; vinylidene halides such as vinylidene chloride; . Among these, (meth)acrylic acid esters are preferred, and alkyl (meth)acrylates are more preferred.
The number of carbon atoms in the alkyl group in the alkyl (meth)acrylate is preferably 1 or more, more preferably 6 or more, still more preferably 10 or more, and is preferably 24 or less, more preferably 22 or less, and still more preferably 20. It is below.
Examples of alkyl (meth)acrylates include methyl (meth)acrylate, ethyl (meth)acrylate, (iso)propyl (meth)acrylate, (iso- or tertiary) butyl (meth)acrylate, (meth)acrylate, ) (iso)amyl acrylate, cyclohexyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, (iso)octyl (meth)acrylate, (iso)decyl (meth)acrylate, (meth)acrylic acid ( iso) dodecyl, (iso) palmityl (meth) acrylate, (iso) stearyl (meth) acrylate, (iso) behenyl (meth) acrylate, and 2-ethylhexyl (meth) acrylate or (meth) Stearyl acrylate is preferred, and stearyl (meth)acrylate is more preferred.
In addition, "(iso or tertiary)" and "(iso)" mean both when these prefixes exist and when they do not exist, and when these prefixes do not exist, normal is indicated. Moreover, "(meth)acrylic acid" indicates acrylic acid or methacrylic acid.

The (meth)acrylic acid ester content in the raw material monomers of the addition polymerized resin segment is preferably 5% by mass or more, more preferably 10% by mass or more, still more preferably 15% by mass or more, and preferably 50% by mass or more. % by mass or less, more preferably 35% by mass or less, and even more preferably 25% by mass or less.
The total amount of the styrenic compound and the (meth)acrylic acid ester in the raw material monomers of the addition polymerization resin segment is preferably 80% by mass or more, more preferably 90% by mass or more, still more preferably 95% by mass or more, and still more. Preferably it is 100% by mass.

Composite resin D preferably has structural units derived from bi-reactive monomers that are covalently bonded to polyester resin segments and addition polymerized resin segments.
The “structural unit derived from a bireactive monomer” means a unit obtained by reacting a functional group and an addition polymerizable group of a bireactive monomer.
Examples of addition polymerizable groups include carbon-carbon unsaturated bonds (ethylenically unsaturated bonds).
The bi-reactive monomers include, for example, addition polymerizable monomers having at least one functional group selected from a hydroxyl group, a carboxyl group, an epoxy group, a primary amino group and a secondary amino group in the molecule. . Among these, addition polymerizable monomers having at least one functional group selected from a hydroxyl group and a carboxy group are preferred, and addition polymerizable monomers having a carboxy group are more preferred, from the viewpoint of reactivity.
Addition-polymerizable monomers having a carboxy group include, for example, acrylic acid, methacrylic acid, fumaric acid, and maleic acid. Among these, acrylic acid and methacrylic acid are preferred, and acrylic acid is more preferred, from the viewpoint of reactivity in both polycondensation reaction and addition polymerization reaction.
When the bireactive monomer is an addition-polymerizable monomer having a carboxy group, the amount of the structural unit derived from the bireactive monomer is preferably 1 mol per 100 mol parts of the alcohol component of the polyester resin segment of composite resin D. mol parts or more, more preferably 5 mol parts or more, still more preferably 8 mol parts or more, and preferably 30 mol parts or less, more preferably 25 mol parts or less, still more preferably 20 mol parts or less.

The content of the polyester resin segment in composite resin D is preferably 35% by mass or more, more preferably 45% by mass or more, still more preferably 50% by mass or more, and preferably 90% by mass or less, more preferably It is 85% by mass or less, more preferably 75% by mass or less.

The content of the addition polymerized resin segment in composite resin D is preferably 5% by mass or more, more preferably 15% by mass or more, still more preferably 25% by mass or more, and preferably 60% by mass or less, more preferably is 55% by mass or less, more preferably 45% by mass or less.

The amount of structural units derived from the bi-reactive monomer in composite resin D is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and still more preferably 0.8% by mass or more, and It is preferably 10% by mass or less, more preferably 5% by mass or less, and even more preferably 3% by mass or less.

The total amount of the polyester resin segment, the addition polymerization resin segment, and the structural units derived from the bi-reactive monomer in the composite resin D is preferably 80% by mass or more, more preferably 90% by mass or more, and still more preferably 95% by mass or more. Yes, and not more than 100% by mass, and even more preferably 100% by mass.

The composite resin D may be produced by a method including a step A of polycondensing an alcohol component and a carboxylic acid component and a step B of addition polymerizing a raw material monomer of an addition polymerized resin segment and a bi-reactive monomer.
In the production of composite resin D, step B may be performed after step A, step A may be performed after step B, or step A and step B may be performed simultaneously.
In step A, a part of the carboxylic acid component is subjected to a polycondensation reaction, and then step B is performed, and then the remainder of the carboxylic acid component is added to the polymerization system to perform the polycondensation reaction of step A and, if necessary, both reactions. A method of further advancing the reaction with the organic monomer is preferred.

The softening point of composite resin D is preferably 70° C. or higher, more preferably 80° C. or higher, and preferably 140° C. or lower, more preferably 120° C. or lower, and still more preferably 100° C. or lower.
Other suitable ranges of resin properties of Composite Resin D are the same as the examples shown in Polyester Resin A above. A dispersion of the resin particles P can be obtained, for example, by the above-described phase inversion emulsification method.
The volume-median particle size _D50 of the resin particles P is preferably 0.01 μm or more, more preferably 0.03 μm or more, and preferably 0.3 μm or less, from the viewpoint of the dispersion stability of the release agent particles. , and more preferably 0.2 μm or less.
From the viewpoint of the dispersion stability of the release agent particles W, the CV value of the resin particles P is preferably 10% or more, more preferably 20% or more, and preferably 40% or less, more preferably 35% or less. , more preferably 30% or less.

The release agent particle dispersion is obtained, for example, by dispersing a release agent, a dispersion of resin particles P, and optionally an aqueous medium at a temperature equal to or higher than the melting point of the release agent in a homogenizer, a high-pressure disperser, or an ultrasonic disperser. It is obtained by dispersing using a dispersing machine having a strong shearing force such as.
The heating temperature during dispersion is preferably the melting point of the release agent or higher and 80°C or higher, more preferably 85°C or higher, and still more preferably 90°C or higher, and preferably softens the resin contained in the resin particles P. It is less than 10°C higher than the point and 100°C or less, more preferably 98°C or less, still more preferably 95°C or less.

The amount of resin particles P is preferably 5 parts by mass or more, more preferably 8 parts by mass or more, still more preferably 10 parts by mass or more, and preferably 70 parts by mass or less with respect to 100 parts by mass of the release agent. , more preferably 60 parts by mass or less, and still more preferably 50 parts by mass or less.

The volume-median particle size _D50 of the release agent particles W is preferably 0.05 μm or more, more preferably 0.2 μm or more, still more preferably 0.3 μm or more, from the viewpoint of obtaining uniform aggregated particles, and , preferably 1 μm or less, more preferably 0.8 μm or less, and still more preferably 0.6 μm or less.
The CV value of the release agent particles is preferably 10% or more, more preferably 20% or more, and preferably 40% or less, more preferably 35% or less, still more preferably 30% or less.
The method for measuring the volume-median particle diameter _D50 and the CV value of the release agent particles W is according to the method described in Examples.

Aggregation of the resin particles X may be performed in the presence of other additives in addition to the colorant particles Z and release agent particles W.
Other additives include, for example, charge control agents, magnetic powders, fluidity improvers, conductivity modifiers, reinforcing fillers such as fibrous substances, antioxidants, anti-aging agents, and cleanability improvers. .

[Surfactant]
In step 1, the dispersion liquid of each particle is mixed to prepare a mixed dispersion liquid, and the resin particles X and optionally added colorant particles Z, release agent particles W, and other optional components are stabilized in dispersion. From the viewpoint of improving the properties, the reaction may be carried out in the presence of a surfactant. Examples of surfactants include anionic surfactants such as alkylbenzenesulfonates and alkylether sulfates; nonionic surfactants such as polyoxyethylene alkyl ethers and polyoxyethylene alkenyl ethers.
When a surfactant is used, the amount used is preferably 0.1 parts by mass or more, more preferably 0.5 parts by mass or more, and preferably 10 parts by mass with respect to 100 parts by mass of the resin particles X. parts or less, more preferably 5 parts by mass or less, and even more preferably 3 parts by mass or less.

The dispersion of the resin particles X, the dispersion of the colorant particles Z, the dispersion of the release agent particles W, and the optional components are mixed by a conventional method. From the viewpoint of efficient aggregation, it is preferable to add a flocculant to the mixed dispersion obtained by the mixing.

[Flocculant]
Examples of flocculants include cationic surfactants such as quaternary salts, organic flocculants such as polyethyleneimine, and inorganic flocculants. Examples of inorganic flocculants include inorganic metal salts such as sodium sulfate, sodium nitrate, sodium chloride, calcium chloride and calcium nitrate; inorganic ammonium salts such as ammonium sulfate, ammonium chloride and ammonium nitrate; and divalent or higher metal complexes. .
From the viewpoint of improving cohesiveness and obtaining uniform aggregated particles, an inorganic flocculant having a valence of 1 to 5 is preferable, an inorganic metal salt having a valence of 1 to 2 and an inorganic ammonium salt are more preferable, and an inorganic ammonium salt is preferable. More preferred is ammonium sulfate.

Using an aggregating agent, for example, 5 parts by mass or more and 50 parts by mass or less of an aggregating agent is added to a mixed dispersion containing resin particles X and colorant particles Z at a temperature of 0° C. or higher and 40° C. or lower with respect to a total amount of 100 parts by mass of the resin. Then, the resin particles X and the colorant particles Z are aggregated in the aqueous medium to obtain aggregated particles. Furthermore, from the viewpoint of promoting aggregation, it is preferable to raise the temperature of the dispersion after adding the aggregating agent.

The aggregation may be stopped when the aggregated particles have grown to a particle size suitable for toner particles.
Methods for stopping aggregation include a method of cooling the dispersion, a method of adding an aggregation inhibitor, and a method of diluting the dispersion. From the viewpoint of reliably preventing unnecessary aggregation, a method of stopping aggregation by adding an aggregation terminator is preferred.

[Aggregation terminating agent]
As the aggregation terminator, a surfactant is preferred, and an anionic surfactant is more preferred. Examples of anionic surfactants include alkylbenzene sulfonates, alkyl sulfates, alkyl ether sulfates, polyoxyalkylene alkyl ether sulfates, and the like. These may be used alone or in combination of two or more. The aggregation terminator may be added in the form of an aqueous solution.
The addition amount of the aggregation terminator is preferably 1 part by mass or more, more preferably 5 parts by mass or more with respect to 100 parts by mass of the resin in the resin particles, from the viewpoint of reliably preventing unnecessary aggregation, and , preferably 60 parts by mass or less, more preferably 30 parts by mass or less, and even more preferably 20 parts by mass or less, from the viewpoint of reducing the residual amount in the toner.

The volume-median particle diameter _D50 of the aggregated particles is preferably 2 μm or more, more preferably 3 μm or more, still more preferably 4 μm or more, and preferably 10 μm or less, more preferably 8 μm or less, further preferably 6 μm or less. be. The volume-median particle diameter _D50 of the aggregated particles is determined by the method described in Examples below.

<Step 2>
In step 2, for example, aggregated particles are fused in an aqueous medium.
By fusion, each particle contained in the aggregated particles is fused to obtain fused particles. Fusing is usually performed in an aqueous medium.
The fusion temperature is preferably at least the glass transition temperature of the polyester resin A, more preferably at least 5°C higher than the glass transition temperature of the polyester resin A, and still more preferably at least from the viewpoint of efficiently promoting the fusion of the aggregated particles. is at least 10°C higher than the glass transition temperature of polyester resin A, preferably at most 30°C higher than the glass transition temperature of polyester resin A, and more preferably at a temperature higher than 25°C higher than the glass transition temperature of polyester resin A. It is below. However, from the viewpoint of suppressing the dissociation of the blocked isocyanate compound as described later, the fusion temperature is preferably lower than the dissociation temperature of the blocked isocyanate.
The volume-median particle diameter _D50 of the fused particles obtained by fusion is preferably 2 μm or more, more preferably 3 μm or more, still more preferably 4 μm or more, and preferably 10 μm or less, more preferably 8 μm or less. , and more preferably 6 μm or less.

The degree of circularity of the fused particles obtained by fusion bonding is preferably 0.955 or more, more preferably 0.960 or more, and is preferably 0.990 or less, more preferably 0.985 or less, and still more preferably 0.980 or less.
It is preferable that the fusion-bonding is completed after reaching the above-mentioned preferable degree of circularity.

<Post-treatment process>
A post-treatment step may be performed after step 2 to obtain toner particles by isolating the fusing particles. Since the fused particles obtained in step 2 are present in the aqueous medium, it is preferable to perform solid-liquid separation first. A suction filtration method or the like is preferably used for the solid-liquid separation.
Washing is preferably performed after solid-liquid separation. At this time, since it is preferable to remove the added surfactant as well, it is preferable to wash with an aqueous medium at a temperature not higher than the cloud point of the surfactant. Washing is preferably performed multiple times.
Drying is then preferably carried out. Drying methods include, for example, vacuum low temperature drying, vibratory fluidized drying, spray drying, freeze drying, and flash jet.

In the present invention, it is preferable to carry out production at a temperature below the dissociation temperature of the blocked isocyanate in all steps after the addition of the blocked isocyanate compound. , more preferably 80° C. or lower, still more preferably 75° C. or lower.
By adding the blocked isocyanate compound and setting the subsequent production temperature within the above range, the dissociation of the blocked isocyanate compound during production can be suppressed, and the blocking agent is dissociated for the first time during fixing, and the isocyanate compound is released. can cause a cross-linking reaction between the isocyanate group of and the hydroxyl group of the polyester resin. As a result, a toner having excellent low-temperature fixability, excellent hot offset resistance, and high image fastness can be obtained.

[Toner particles]
The volume-median particle diameter _D50 of the toner particles is preferably 2 μm or more, more preferably 3 μm or more, and still more preferably 4 μm or more, from the viewpoint of obtaining high-quality images and further improving the cleanability of the toner. And it is preferably 10 μm or less, more preferably 8 μm or less, still more preferably 6 μm or less.
The circularity of the toner particles is preferably 0.955 or more, more preferably 0.960 or more, and preferably 0.990 or less, more preferably 0.985 or less, from the viewpoint of obtaining high-quality images. More preferably, it is 0.980 or less.
The volume-median particle diameter _D50 and circularity of the toner particles can be measured by the methods described in the Examples.

[toner]
The toner includes toner particles. The toner particles contain a polyester-based resin and a blocked isocyanate, the polyester-based resin has a structural unit derived from a polyol and a structural unit derived from a polycarboxylic acid, and has a structure derived from the polycarboxylic acid. The unit contains a structural unit derived from a carboxylic acid having a valence of 3 or more, the hydroxyl value of the polyester resin is 5 mgKOH/g or more, and the blocked isocyanate is an adduct-type blocked isocyanate.
Preferred aspects of the polyester resin, blocked isocyanate compound, etc. are as described above.

[External additive]
Although the toner particles can be used as the toner as it is, it is preferable to use the toner after adding a fluidizing agent or the like as an external additive to the surface of the toner particles.
Examples of external additives include fine particles of inorganic materials such as hydrophobic silica, titanium oxide, alumina, cerium oxide, and carbon black, and fine particles of polymers such as polycarbonate, polymethyl methacrylate, and silicone resin. Among these, hydrophobic silica is preferred.
When the toner particles are surface-treated using an external additive, the amount of the external additive added is preferably 1 part by mass or more, more preferably 2 parts by mass or more, and still more preferably 100 parts by mass of the toner particles. It is 3 parts by mass or more, and preferably 5 parts by mass or less, more preferably 4.5 parts by mass or less, and even more preferably 4 parts by mass or less.

The fact that the electrostatic charge image developing toner of the present invention contains a blocked isocyanate can also be evaluated by the fact that the elasticity of the toner is improved by heating. That is, at least part of the blocked isocyanate exists in the toner in a state in which the blocking agent is not dissociated, and the blocking agent dissociates for the first time during fixing to generate isocyanate groups, which react with the hydroxyl groups of the polyester-based resin, resulting in cross-linking. is formed, the elasticity is improved.
If the blocked isocyanate is dissociated before fixing and the reaction between the isocyanate group and the hydroxyl group of the polyester resin proceeds, such improvement in toner elasticity is not observed by heating.
Specifically, it can be confirmed by DSC that the isocyanate group is present in the toner in a state in which the blocking agent is bound. When the blocked isocyanate compound is subjected to DSC measurement, an exothermic peak associated with dissociation of the blocking agent can be observed. By comparing the amount of heat of the exothermic peak of the dissociation of the blocking agent with the amount of heat of the exothermic peak when the toner containing the blocked isocyanate compound is measured, the amount of the isocyanate compound present in the state in which the blocking agent is bound in the toner is determined. can be asked for.
Furthermore, by measuring and comparing the molecular weight of the resin before and after making the toner, it was confirmed that there was no difference in the molecular weight before and after making the toner. It is also possible to confirm that cross-linking caused by dissociation does not occur.

Toners are used for electrostatic image development in electrophotographic printing. The toner can be used, for example, as a one-component developer or mixed with a carrier as a two-component developer.

EXAMPLES The present invention will be described in more detail with reference to Examples and the like below. In the following examples etc., each physical property was measured by the following method.

[Measuring method]
[Acid value and hydroxyl value of resin]
The acid value and hydroxyl value of the resin were measured according to JIS K0070:1992. However, a mixed solvent of acetone and toluene [acetone:toluene=1:1 (volume ratio)] was used as the measurement solvent.

[Resin softening point, crystallinity index, melting point and glass transition temperature]
(1) Softening point Using a flow tester "CFT-500D" (manufactured by Shimadzu Corporation), while heating a 1 g sample at a temperature increase rate of 6 ° C./min, a load of 1.96 MPa is applied with a plunger, and the diameter It was extruded through a 1 mm, 1 mm long nozzle. The amount of plunger depression of the flow tester was plotted against the temperature, and the softening point was defined as the temperature at which half of the sample flowed out.

(2) Glass transition temperature Using a differential scanning calorimeter "Q-100" (manufactured by TA Instruments Japan Co., Ltd.), 0.01 g of the sample was weighed into an aluminum pan, heated to 200 ° C., and the temperature It was cooled to 0°C at a cooling rate of 10°C/min. After that, the temperature was raised at a rate of temperature rise of 10° C./min, and the calorie was measured. Among the observed endothermic peaks, the peak temperature with the maximum peak area was taken as the maximum endothermic peak temperature. The glass transition temperature was defined as the temperature at the intersection of the extended line of the baseline below the maximum endothermic peak temperature and the tangent line showing the maximum slope from the rising portion of the peak to the apex of the peak.

[Melting point of release agent]
Using a differential scanning calorimeter "Q-100" (manufactured by TA Instruments Japan Co., Ltd.), 0.01 g of the sample was weighed into an aluminum pan, heated to 200 ° C., and then cooled at a rate of 10 ° C. from 200 ° C. /min to 0°C. Next, the temperature of the sample was increased at a temperature increase rate of 10° C./min, the calorie was measured, and the maximum endothermic peak temperature was defined as the melting point.

[Volume Median Particle Diameter (D ₅₀ ) and CV Value of Resin Particles, Release Agent Particles, and Colorant Particles]
(1) Measuring device: Laser diffraction particle size measuring machine “LA-920” (manufactured by HORIBA, Ltd.)
(2) Measurement conditions: A sample dispersion was placed in a measurement cell, distilled water was added, and the volume-median particle size (D ₅₀ ) and volume-average particle size were measured at a concentration that brought the absorbance to an appropriate range. Also, the CV value was calculated according to the following formula.
CV value (%) = (standard deviation of particle size distribution/volume average particle size) x 100

[Solid Content Concentration of Resin Particle Dispersion, Release Agent Particle Dispersion, and Colorant Particle Dispersion]
Using an infrared moisture meter "FD-230" (manufactured by Ketsuto Kagaku Kenkyusho Co., Ltd.), 5 g of the measurement sample is dried at a temperature of 150 ° C., under the conditions of measurement mode 96 (monitoring time 2.5 minutes, fluctuation width 0.05%). , and the water content (% by mass) of the dispersion was measured. The solid content concentration was calculated according to the following formula.
Solid content concentration (mass%) = 100 - moisture (mass%)

[Volume-median particle diameter (D ₅₀ ) of aggregated particles]
The volume-median particle size ( _D50 ) of aggregated particles was measured as follows.
・Measuring machine: “Coulter Multisizer (registered trademark) III” (manufactured by Beckman Coulter, Inc.)
・Aperture diameter: 50 μm
・ Analysis software: “Multisizer (registered trademark) III version 3.51” (manufactured by Beckman Coulter, Inc.)
・ Electrolyte: “Isoton (registered trademark) II” (manufactured by Beckman Coulter, Inc.)
Measurement conditions: By adding the sample dispersion to 100 mL of the electrolytic solution, the particle size of 30,000 particles is adjusted to a concentration that can be measured in 20 seconds, and then 30,000 particles are measured again, and the particle size The volume median particle size ( _D50 ) was determined from the distribution.

[Circularity of Toner Particles]
The circularity of toner particles was measured under the following conditions.
・ Measuring device: Flow type particle image analyzer “FPIA-3000” (manufactured by Sysmex Corporation)
Preparation of dispersion liquid: A dispersion liquid of toner particles was diluted with deionized water so as to have a solid content concentration of 0.001 to 0.05% by mass.
・Measurement mode: HPF measurement mode

[Volume Median Particle Diameter of Toner Particles ( _D50 )]
The volume median particle size ( _D50 ) of the toner particles was measured as follows.
The measuring device, aperture diameter, analysis software, and electrolytic solution used were the same as those used in the measurement of the volume-median particle diameter (D ₅₀ ) of the aggregated particles described above.
- Dispersion: Polyoxyethylene lauryl ether "Emulgen (registered trademark) 109P" (manufactured by Kao Corporation, HLB (Hydrophile-Lipophile Balance) = 13.6) is dissolved in the electrolytic solution to obtain a dispersion with a concentration of 5% by mass. got
Dispersion conditions: 10 mg of a measurement sample of dried toner particles is added to 5 mL of the dispersion liquid, dispersed for 1 minute with an ultrasonic disperser, and then 25 mL of an electrolytic solution is added, followed by an ultrasonic disperser. Disperse for 1 minute to prepare a sample dispersion.
Measurement conditions: By adding the sample dispersion to 100 mL of the electrolytic solution, the particle size of 30,000 particles is adjusted to a concentration that can be measured in 20 seconds, and then 30,000 particles are measured. The volume-median particle size ( _D50 ) and volume-average particle size were obtained from the distribution.

[Evaluation method]
[Toner fixability (low temperature fixability) and hot offset resistance]
Using a commercially available printer "Microline (registered trademark) 5400" (manufactured by Oki Data Co., Ltd.) on high-quality paper "J paper A4 size" (manufactured by Fuji Xerox Co., Ltd.), the toner adhesion amount on the paper is 1.49 to 1. A solid image of 0.51 mg/cm ² was output on A4 paper with a length of 50 mm, leaving a margin of 5 mm from the top edge, without being fixed. Next, the printer was prepared by modifying the fixing device to be variable in temperature and speed, and the temperature of the fixing device was set to 180° C., and the toner was fixed at a printing speed of 15 ppm in the vertical direction of A4 to obtain prints.
A piece of mending tape "Scotch (registered trademark) Mending Tape 810" (manufactured by Sumitomo 3M Co., Ltd., width 18 mm) cut into a length of 50 mm is lightly pasted from the top margin of the printed image to the solid image. After that, a weight of 500 g (contact area: 1963 mm ² ) was placed and pressed once at a speed of 10 mm/s. After that, the attached tape was peeled off from the lower end side at a peeling angle of 180° and a speed of 10 mm/s to obtain a print after tape peeling. Thirty sheets of high-quality paper "Excellent White Paper A4 size" (manufactured by Oki Data Co., Ltd.) were placed under the printed matter before and after the tape was applied, and the reflected image density of the fixed image portion of each printed matter was measured before and after the tape was applied. , SpectroEye colorimeter (manufactured by GretagMacbeth, light irradiation conditions; standard light source D50, observation field of view 2°, density standard DINNB, absolute white standard). was calculated.
Fixing rate (%) = (reflected image density after tape removal/reflected image density before tape application) x 100
When the fixing rate was 90% or more, it was determined that the toner had been fixed.
In addition, the image of the printed matter was visually checked, and the occurrence of offset (hot offset) at 180° C. was also checked.

[Bending resistance]
A printed matter prepared in the same manner as above was folded so that the image was on the outside, and a weight of 500 g was placed on the folded portion and pressed for one reciprocation. After that, with the folded image unfolded, a mending tape “Scotch (registered trademark) Mending Tape 810” (manufactured by Sumitomo 3M Co., Ltd., width 18 mm) was cut to a length of 50 mm on the folded portion. After lightly sticking the object, a weight of 500 g (contact area: 1963 mm ² ) was placed and pressed once at a speed of 10 mm/s. After that, the attached tape was peeled off from the lower end side at a peeling angle of 180° and a speed of 10 mm/s to obtain a print after tape peeling.
After the tape was peeled off, the bent portion was visually observed and evaluated according to the following five grades. The higher the score, the better the bending resistance.
<Evaluation Criteria>
5 points: No peeling is observed at the bent portion.
4 points Slight peeling is observed on the bending line.
3 points Delamination with a width of less than 2 mm is observed along the folding line.
2 points Peeling with a width of 2 mm or more and less than 4 mm is observed along the bending line.
1 point Peeling with a width of 4 mm or more is observed along the bending line.

[Resin production]
Production example A1 (production of amorphous resin A1)
The inside of a four-necked flask with an internal volume of 10 L equipped with a nitrogen inlet tube, a dehydration tube, a stirrer, and a thermocouple was replaced with nitrogen, and 5525 g of ethylene oxide (2.2) adduct of bisphenol A, 1976 g of terephthalic acid, di( 2-Ethylhexanoic acid) tin (II) 40 g and gallic acid 4 g were added, and the temperature was raised to 235°C while stirring under a nitrogen atmosphere. It was held at 8 kPa for 1 hour. After returning to atmospheric pressure, the mixture was cooled to 180°C, 296 g of fumaric acid, 392 g of trimellitic anhydride, and 2.9 g of 4-tert-butylcatechol were added, and the temperature was raised to 220°C at a rate of 10°C/hr. After that, the pressure in the flask was lowered, and the reaction was carried out to the desired softening point at 10 kPa to obtain an amorphous resin A1.

Production example A2 (production of amorphous resin A2)
The inside of a four-necked flask with an internal volume of 10 L equipped with a nitrogen inlet tube, a dehydration tube, a stirrer, and a thermocouple was replaced with nitrogen, and 3486 g of ethylene oxide (2.2) adduct of bisphenol A and propylene oxide of bisphenol A ( 2.2) Add 2021 g of the adduct, 1917 g of terephthalic acid, 40 g of di(2-ethylhexanoic acid)tin(II) and 4 g of gallic acid, and heat to 235°C under a nitrogen atmosphere while stirring. After holding the pressure at 8 kPa for 8 hours, the pressure in the flask was lowered and the pressure was held at 8 kPa for 1 hour. After returning to atmospheric pressure, the mixture was cooled to 180°C, 287 g of fumaric acid, 317 g of trimellitic anhydride, and 2.9 g of 4-tert-butylcatechol were added, and the temperature was raised to 220°C at a rate of 10°C/hr. After that, the pressure in the flask was lowered, and the reaction was carried out to the desired softening point at 10 kPa to obtain an amorphous resin A2.

Production Example A3 (Production of Amorphous Resin A3)
The inside of a four-necked flask with an internal volume of 10 L equipped with a nitrogen inlet tube, a dehydration tube, a stirrer, and a thermocouple was replaced with nitrogen, and 2034 g of propylene oxide (2.2) adduct of bisphenol A and ethylene oxide of bisphenol A ( 2.2) Add 3507 g of the adduct, 1929 g of terephthalic acid, 40 g of di(2-ethylhexanoic acid)tin(II) and 4 g of gallic acid, and heat to 235°C under a nitrogen atmosphere while stirring. After holding the pressure at 8 kPa for 8 hours, the pressure in the flask was lowered and the pressure was held at 8 kPa for 1 hour. Then, after returning to atmospheric pressure, cool to 180° C., add 578 g of fumaric acid and 5.8 g of 4-tert-butylcatechol, raise the temperature to 220° C. at a rate of 10° C./hr, and then pressurize in the flask. was lowered and the reaction was carried out at 10 kPa to the desired softening point to obtain an amorphous resin A3.

Production Example D1 (Production of Amorphous Resin D1)
The inside of a 10 L four-neck flask equipped with a nitrogen inlet tube, a dehydration tube, a stirrer, and a thermocouple was purged with nitrogen, and 4313 g of propylene oxide (2.2) adduct of bisphenol A, 818 g of terephthalic acid, and succinic acid were added. 727 g of acid, 30 g of di(2-ethylhexanoic acid) tin (II), and 3 g of gallic acid were added, heated to 235° C. with stirring under a nitrogen atmosphere, and maintained at 235° C. for 5 hours. was lowered and held at 8 kPa for 1 hour. After returning to atmospheric pressure, the system was cooled to 160°C, and a mixture of 2755 g of styrene, 689 g of stearyl methacrylate, 142 g of acrylic acid, and 413 g of dibutyl peroxide was added dropwise over 1 hour while the temperature was maintained at 160°C. Then, after holding at 160° C. for 30 minutes, the temperature was raised to 200° C., the pressure in the flask was further lowered, and reaction was carried out to a desired softening point at 8 kPa to obtain amorphous resin D1. Various physical properties of the resin were measured and shown in Table 1.

[Production of resin particle dispersion]
Production Example X1 (Production of Resin Particle Dispersion X-1)
300 g of amorphous resin A1 and 300 g of methyl ethyl ketone were placed in a container with an internal volume of 3 L equipped with a stirrer "Three One Motor BL300" (manufactured by Shinto Scientific Co., Ltd.), a reflux condenser, a dropping funnel, a thermometer and a nitrogen inlet tube. was added, and the resin was dissolved at 30° C. for 2 hours. A 5% by mass sodium hydroxide aqueous solution was added to the resulting solution so that the degree of neutralization would be 65 mol% with respect to the acid value of the resin, and the mixture was stirred for 30 minutes.
Next, while maintaining the temperature at 30 ° C., a blocked isocyanate compound (Duranate SBF-70E: manufactured by Asahi Kasei Corporation, solid content 70%, effective NCO = 6.2 wt%, adduct mold) was added and stirred for 30 minutes. Then, 600 g of deionized water was added over 60 minutes while stirring at 200 r/min (peripheral speed of 63 m/min) while maintaining the temperature at 30° C. for phase inversion emulsification.
Thereafter, the temperature was raised to 73°C over 20 minutes, and after reaching 73°C, methyl ethyl ketone was distilled off under reduced pressure while the temperature was maintained at 73°C to obtain an aqueous dispersion. After that, the aqueous dispersion was cooled to 30° C. while stirring, and then deionized water was added to adjust the solid content concentration to 30% by mass. X1 was obtained. Table 2 shows the volume-median particle diameter _D50 and CV value of the obtained resin particles.

Production Examples X2, X3, Y1 to Y5, P1 (Production of Resin Particle Dispersions X-2, X-3, Y-1 to Y-5, P-1)
A resin particle dispersion was obtained in the same manner as in Production Example X1, except that the combinations of the amorphous resin and blocked isocyanate used were as shown in Table 2. Table 2 shows the volume-median particle diameter _D50 and CV value of the obtained resin particles.

[Production of Release Agent Particle Dispersion]
Production Example W1 (Production of Release Agent Particle Dispersion W-1)
120 g of deionized water, 53 g of resin particle dispersion liquid P-1, and 40 g of paraffin wax "HNP-9" (manufactured by Nippon Seiro Co., Ltd., melting point 75 ° C.) were added to a beaker with an internal volume of 1 L, and the temperature was increased to 90 to 95 ° C. The temperature was maintained to melt and stir to obtain a molten mixture. While maintaining the temperature at 90 to 95° C., dispersion treatment was performed for 20 minutes using an ultrasonic homogenizer “US-600T” (manufactured by Nippon Seiki Seisakusho Co., Ltd.), and then cooled to room temperature. Deionized water was added to the resulting dispersion to adjust the solid content concentration to 20% by mass to obtain release agent particle dispersion W-1. The volume median particle size ( _D50 ) was 0.45 μm and the CV value was 26%.

[Production of colorant particle dispersion]
Production Example Z1 (Production of Colorant Particle Dispersion Z-1)
In a beaker with an internal volume of 1 L, copper phthalocyanine pigment "ECB-301" (manufactured by Dainichiseika Kogyo Co., Ltd.) 136.0 g, anionic surfactant "Neoperex (registered trademark) G-15" (manufactured by Kao Corporation, 181.3 g of a 15% by mass sodium dodecylbenzenesulfonate aqueous solution) and 340 g of deionized water were mixed and dispersed at room temperature for 3 hours using a homogenizer. was added to obtain a colorant particle dispersion Z-1. The volume median particle size ( _D50 ) of the colorant particles in the dispersion was 0.12 μm.

[Toner production]
Example 1 (Preparation of Toner 1)
300 g of resin particle aqueous dispersion X1, 31.5 g of release agent particle dispersion W-1, and a colorant particle dispersion were placed in a four-necked flask with an internal volume of 3 L equipped with a dehydration tube, a stirrer, and a thermocouple. 26.6 g of Z-1, nonionic surfactant "Emulgen (registered trademark) 150" (manufactured by Kao Corporation, polyoxyethylene (average number of moles added: 50) lauryl ether) 10% by weight aqueous solution 9 g, anionic 6 g of surfactant "Neopelex G15" (manufactured by Kao Corporation, sodium dodecylbenzenesulfonate, effective concentration: 15%) and 137.0 g of deionized water were mixed at a temperature of 25°C. Next, while stirring the mixture, an aqueous solution of 25.9 g of ammonium sulfate dissolved in 407 g of deionized water was added with 12.7 g of a 4.8% by mass potassium hydroxide aqueous solution to adjust the pH to 8.1. C. over 15 minutes. After that, the temperature was raised to 60° C. over 2 hours and maintained at 60° C. until the volume median particle diameter (D ₅₀ ) of the aggregated particles reached 6.8 μm to obtain an aggregated particle dispersion.
To the aggregated particle dispersion, 32.1 g of an anionic surfactant "Emal (registered trademark) E-27C" (manufactured by Kao Corporation, sodium polyoxyethylene lauryl ether sulfate, effective concentration: 27% by mass), 1896 g of deionized water. , was added. After that, the temperature was raised to 75° C. over 1 hour. After reaching 75° C., 41 g of 0.1 mol/L sulfuric acid aqueous solution was added. By maintaining the temperature at 75° C. for 30 minutes, a dispersion liquid of fused particles in which aggregated particles are fused was obtained.
The obtained dispersion of fused particles is cooled to 30° C., suction filtered to separate solids, washed with deionized water at 25° C., and vacuum-dried at 35° C. for 48 hours to obtain toner particles. got 100 parts by mass of the toner particles, 2.5 parts by mass of hydrophobic silica “RY50” (manufactured by Nippon Aerosil Co., Ltd., number average particle diameter: 0.04 μm), and hydrophobic silica “Cabosil (registered trademark) TS720” (Cabot Japan) Co., Ltd., number average particle size; The viscoelasticity of the obtained toner 1 was measured under constant temperature conditions, and the elasticity increased with the lapse of time. Therefore, it was confirmed that the added blocked isocyanate compound was contained in the toner in an unreacted state.

Examples 2-3, Comparative Examples 1-5
A toner was obtained in the same manner as in Example 1 except that the resin particle dispersion liquid shown in Table 3 was used.

From the results of Examples and Comparative Examples, it can be seen that the present invention can provide a toner having excellent low-temperature fixability, excellent hot offset resistance, and high fastness images.
Comparing Example 1 with Comparative Example 1, the toner of Comparative Example 1, which does not contain a blocked isocyanate compound, causes hot offset at 180° C., and the image fastness is not sufficient. Further, when comparing Example 1 and Comparative Example 2, in Comparative Example 2 in which the polyester-based resin does not contain a polyvalent carboxylic acid component having a valence of 3 or higher, compared with Comparative Example 1, the fastness of the image is slightly lower. An increase was observed, but compared with Example 1, the image fastness cannot be said to be sufficient.
Further, when comparing Example 1 with Comparative Examples 3, 4 and 5, Comparative Examples 3 and 4 using an isocyanurate-type blocked isocyanate compound and a biuret-type blocked isocyanate compound were used as the blocked isocyanate. Even in Comparative Example 5, a slight improvement in image fastness was observed as compared with Comparative Example 1, but compared with Example 1, it was not sufficient and hot offset occurred.

Claims (5)

Contains polyester resin and blocked isocyanate,
The polyester resin has a structural unit derived from a polyol and a structural unit derived from a polycarboxylic acid,
The structural unit derived from the polycarboxylic acid contains a structural unit derived from a trivalent or higher carboxylic acid,
The hydroxyl value of the polyester resin is 5 mgKOH/g or more,
The blocked isocyanate is an adduct-type blocked isocyanate,
Toner for electrostatic charge image development. 2. The toner for electrostatic charge image development according to claim 1, wherein the dissociation temperature of the blocking agent for the blocked isocyanate is 150[deg.] C. or lower. 3. The toner for electrostatic charge image development according to claim 1, wherein said blocked isocyanate blocking agent is selected from oxime-type and pyrazole-type blocking agents. A step of aggregating resin particles containing a polyester resin and a blocked isocyanate to obtain aggregated particles, and a step of fusing the aggregated particles,
The polyester resin has a structural unit derived from a polyol and a structural unit derived from a polycarboxylic acid,
The structural unit derived from the polycarboxylic acid contains a structural unit derived from a trivalent or higher carboxylic acid,
The hydroxyl value of the polyester resin is 5 mgKOH/g or more,
The blocked isocyanate is an adduct-type blocked isocyanate,
In all steps after adding the blocked isocyanate, production is performed at a temperature below the dissociation temperature of the blocking agent of the blocked isocyanate.
A method for producing a toner for electrostatic charge image development. 5. The method for producing a toner for electrostatic charge image development according to claim 4, wherein the production is carried out at 90[deg.] C. or less in all steps after adding the blocked isocyanate.