JP2011107339A - Method for producing binder resin for toner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce variation of particle diameters with respect to changes in a neutralization degree upon preparing a crystalline polyester in an aqueous dispersion, to reduce a coefficient of variation (CV value) in the particle size distribution of the crystalline polyester particles, and to obtain an electrophotographic toner excellent in low temperature fixing property, glossiness and durability at normal temperature and high humidity. <P>SOLUTION: Provided is a method for producing the binder resin for toner, including the following step 1 to step 4. In a step 1, an alcohol component containing a 2-10C aliphatic diol and a carboxylic acid component containing at least one kind selected from aromatic dicarboxylic acid compounds and 2-6C aliphatic dicarboxylic acid compounds are subjected to a condensation polymerization reaction, then the product is cooled down to 50°C or lower and heated to a temperature over 50°C and in a range from (the highest endothermic peak temperature (°C)-60°C) to (the highest endothermic peak temperature (°C)-5°C) to obtain a crystalline polyester. In a step 2, an aqueous dispersion liquid containing the crystalline polyester obtained in the step 1 is obtained. In a step 3, the aqueous dispersion liquid containing the crystalline polyester obtained in the step 2 is mixed with an aqueous dispersion liquid containing an amorphous resin, and the mixture is subjected to an aggregation step to obtain an aqueous dispersion liquid of aggregated particles. In a step 4, the aqueous dispersion liquid of the aggregated particles obtained in the step 3 is subjected to a uniting step to obtain an aqueous dispersion liquid of coalesced particles. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a method for producing a binder resin for toner, an electrophotographic toner containing the binder resin obtained by the production method, a method for producing crystalline polyester for toner, and the crystallinity for toner obtained by the production method. Relates to polyester.

Crystalline polyester, unlike other crystalline resins such as polyethylene, is highly compatible with amorphous polyester, easy to disperse, and has a sharp melt property in which crystal parts are expressed. In recent years, it has attracted attention as a binder resin suitable for improving the low-temperature fixability of toner.
Patent Document 1 discloses a method of melt kneading a raw material containing two or more polyesters, with the object of providing a method capable of producing a toner having excellent low-temperature fixability and having good pulverizability and storage stability. A toner manufacturing method including a heat treatment step, a pulverization step, and a classification step, wherein the two or more kinds of polyesters contain at least one amorphous polyester, and the heat treatment step is represented by a specific formula. A method for producing a toner at a satisfactory temperature and time is disclosed.
Patent Document 2 discloses a toner that can be used at a lower fixing temperature, and has a problem of providing a low-melting toner having excellent document offset and heat aggregation properties. A method for producing a toner is disclosed which includes a step of annealing a toner containing a crystalline resin at a temperature within about 10 ° C. of the recrystallization temperature of the crystalline resin.

JP 2005-308995 A JP 2006-276855 A

In the method for producing a binder resin for toner in which an aqueous dispersion containing crystalline polyester is agglomerated and united, the crystalline polyester has a particle size with respect to fluctuations in neutralization degree when it is made into an aqueous dispersion compared to an amorphous resin. There was a problem that the variation was large.
Patent Documents 1 and 2 both disclose toner heat treatment, but do not disclose any of the above-mentioned problems in the so-called chemical method in which crystalline polyester is dissolved and used, and means for solving it.

  An object of the present invention is to solve the above problems, to reduce the variation in the particle size with respect to the variation in the degree of neutralization when the crystalline polyester is made into an aqueous dispersion, and the coefficient of variation (CV) of the particle size distribution of the crystalline polyester particles. And a toner for electrophotography excellent in low-temperature fixability, glossiness and durability at normal temperature and high humidity. Furthermore, a method for producing a binder resin for toner for obtaining an electrophotographic toner having these characteristics, an electrophotographic toner containing the binder resin obtained by the production method, and a method for producing a crystalline polyester for toner And a crystalline polyester for toner obtained by the production method.

The above phenomenon becomes remarkable when an aromatic dicarboxylic acid compound or a lower aliphatic dicarboxylic acid compound is used as the carboxylic acid component. The reason for this is that the dispersion of the size of the spherulites is large, and the binding strength of the polyester in the spherulites is strong, so that the crystalline polyester is finely divided in the aqueous dispersion. It was speculated that the crystallized and non-crystallized sites in the crystalline polyester, the size of the spherulites, etc. were affected, and it became easy to generate coarse particles of the crystalline polyester in the dispersion due to the change in the degree of neutralization. .
In order to stabilize the resin physical properties of the crystalline polyester, the present inventors heat-treat the crystalline polyester under specific conditions before producing an aqueous dispersion containing the crystalline polyester. It has been found that the variation in the particle size with respect to the variation in the degree of neutralization when an aqueous dispersion is used can be reduced, and at the same time, the coefficient of variation (CV value) in the particle size distribution of the crystalline polyester particles is reduced. This is thought to be because the giant spherulites could be reduced and the size of the spherulites became uniform. Further, it has been found that a toner containing a binder resin obtained by using an aqueous dispersion containing a crystalline polyester obtained by the method is excellent in low-temperature fixability, glossiness, and durability at room temperature and high humidity. . This is presumably because the coarse particles of the crystalline polyester were reduced by reducing the giant spherulites.

The present invention relates to the following [1] to [4].
[1] A method for producing a binder resin for toner, comprising the following steps 1 to 4.
Step 1: Polycondensation of an alcohol component containing an aliphatic diol having 2 to 10 carbon atoms and a carboxylic acid component containing one or more selected from an aromatic dicarboxylic acid compound and an aliphatic dicarboxylic acid compound having 2 to 6 carbon atoms After being subjected to the reaction, after cooling to 50 ° C. or lower, the temperature is higher than 50 ° C., and “maximum endothermic peak temperature (° C.)-60 ° C.” to “maximum endothermic peak temperature (° C.)-5 ° C. To obtain a crystalline polyester.
Step 2: A step of obtaining an aqueous dispersion containing the crystalline polyester obtained in Step 1.
Step 3: A step of obtaining an aqueous dispersion of aggregated particles by mixing the aqueous dispersion containing the crystalline polyester obtained in Step 2 with an aqueous dispersion containing an amorphous resin and then subjecting to an aggregation step.
Step 4: A step of obtaining an aqueous dispersion of coalesced particles by subjecting the aqueous dispersion of aggregated particles obtained in Step 3 to an coalescence step.
[2] An electrophotographic toner containing the binder resin for toner obtained by the production method according to [1] above.
[3] A method for producing a crystalline polyester for toner, comprising the following steps 1-1 to 1-3.
Step 1-1: An alcohol component containing an aliphatic diol having 2 to 10 carbon atoms, and a carboxylic acid component containing one or more selected from an aromatic dicarboxylic acid compound and an aliphatic dicarboxylic acid compound having 2 to 6 carbon atoms. A step of subjecting it to a condensation polymerization reaction.
Process 1-2: The process of cooling the polyester obtained at the process 1-1 until it becomes 50 degrees C or less.
Step 1-3: The temperature of the polyester cooled in Step 1-2 is higher than 50 ° C., and “endothermic maximum peak temperature (° C.)-60 ° C.” to “endothermic maximum peak temperature (° C.)-5 ° C. The process of heat-treating.
[4] A crystalline polyester for toner obtained by the production method described in [3] above.

  The crystalline polyester obtained by the production method of the present invention has a characteristic that variation in particle size is reduced with respect to variation in the degree of neutralization when it is made into an aqueous dispersion, so that the reaction can be easily controlled and the crystallinity. The coefficient of variation (CV value) in the particle size distribution of the polyester particles is small. For this reason, an electrophotographic toner containing a binder resin obtained using the crystalline polyester is excellent in low-temperature fixability, glossiness, and durability at room temperature and high humidity.

[Method for producing crystalline polyester]
The present invention is a method for producing a crystalline polyester for toner, comprising the following steps 1-1 to 1-3, preferably for toner obtained by agglomerating and coalescing an aqueous dispersion containing the crystalline polyester. It is a manufacturing method of crystalline polyester used for binder resin.
Step 1-1: An alcohol component containing an aliphatic diol having 2 to 10 carbon atoms, and a carboxylic acid component containing one or more selected from an aromatic dicarboxylic acid compound and an aliphatic dicarboxylic acid compound having 2 to 6 carbon atoms. A step of subjecting it to a condensation polymerization reaction.
Process 1-2: The process of cooling the polyester obtained at the process 1-1 until it becomes 50 degrees C or less.
Step 1-3: The temperature of the polyester cooled in Step 1-2 is higher than 50 ° C., and “endothermic maximum peak temperature (° C.)-60 ° C.” to “endothermic maximum peak temperature (° C.)-5 ° C. The process of heat-treating.

Here, the crystallinity of a resin such as polyester is expressed by the ratio between the softening point and the maximum endothermic peak temperature by the differential scanning calorimeter, that is, the crystallinity index defined by “softening point / maximum endothermic peak temperature”. In general, when the crystallinity index exceeds 1.4, the resin is amorphous, and when it is less than 0.6, the crystallinity is low and there are many amorphous portions. In the present invention, “crystalline polyester” refers to a polyester having a crystallinity index of 0.6 to 1.4, preferably 0.8 to 1.2, more preferably 0.9 to 1.1. “Amorphous resin” refers to a resin having a crystallinity index greater than 1.4 or less than 0.6.
The maximum peak temperature of the endotherm refers to the temperature of the peak on the highest temperature side among the endothermic peaks observed under the conditions of the measurement methods described in the examples. If the maximum peak temperature is within 20 ° C from the softening point, the melting point of the crystalline resin (crystalline polyester) is taken as the melting point, and the peak exceeding 20 ° C is due to the glass transition of the amorphous resin. And
The crystallinity of the resin can be adjusted by the type and ratio of the raw material monomers, production conditions (for example, reaction temperature, reaction time, cooling rate) and the like.
Hereinafter, step 1-1 to step 1-3 will be described in order.

<Step 1-1>
Step 1-1 is at least one selected from an alcohol component containing an aliphatic diol having 2 to 10 carbon atoms, an aromatic dicarboxylic acid compound, an aromatic tricarboxylic acid compound, and an aliphatic dicarboxylic acid compound having 2 to 6 carbon atoms. The carboxylic acid component is subjected to a condensation polymerization reaction.
-Alcohol component-
The alcohol component that is a raw material monomer of the crystalline polyester used in Step 1-1 contains an aliphatic diol having 2 to 10 carbon atoms from the viewpoint of enhancing the crystallinity of the polyester.
Examples of the aliphatic diol having 2 to 10 carbon atoms include ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, Examples include 1,7-heptanediol, 1,8-octanediol, 1,9-nonanediol, neopentyl glycol, and 1,4-butenediol. Among these, aliphatic diols having 4 to 8 carbon atoms are preferable, aliphatic diols having 4 to 6 carbon atoms are more preferable, and α, ω-linear chains having 2 to 10 carbon atoms from the viewpoint of crystallinity. Alkanediols are preferred, 1,4-butanediol and 1,6-hexanediol are more preferred, and 1,4-butanediol and 1,6-hexanediol are more preferably used in combination.
When 1,4-butanediol and 1,6-hexanediol are used in combination as the aliphatic diol having 2 to 10 carbon atoms, the use ratio thereof (1,4-butanediol / 1,6-hexanediol) is: The molar ratio is preferably 5/95 to 50/50, more preferably 10/90 to 50/50, and still more preferably 20/80 to 40/60.

  From the viewpoint of further improving the crystallinity of the crystalline polyester, the content of the aliphatic diol having 2 to 10 carbon atoms is preferably 70 mol% or more, more preferably 80 to 100 mol%, still more preferably, in the alcohol component. 90 to 100 mol%. The content of one kind of α, ω-linear alkanediol in the alcohol component is preferably 70 mol% or more, more preferably 70 to 100 mol%, still more preferably 90 to 100 mol%.

  Examples of the polyhydric alcohol component other than the aliphatic diol having 2 to 10 carbon atoms that can be used as the alcohol component include, for example, a polyoxypropylene adduct of 2,2-bis (4-hydroxyphenyl) propane, 2,2- Aromatic diols such as alkylene oxide adducts of bisphenol A represented by the following formula (I) including polyoxyethylene adducts of bis (4-hydroxyphenyl) propane; 3 such as glycerin, pentaerythritol, trimethylolpropane, etc. Alcohols having a value higher than that are listed.

（式中、Ｒは、炭素数２又は３のアルキレン基を示す。ｘ及びｙは、正の数を示し、ｘとｙの和は、１〜１６、好ましくは１．５〜５である。）

(In formula, R shows a C2-C3 alkylene group. X and y show a positive number, and the sum of x and y is 1-16, Preferably it is 1.5-5. )

-Carboxylic acid component-
The carboxylic acid component, which is a raw material monomer for crystalline polyester, used in Step 1-1 includes low-temperature fixability of toner, gloss of printed images (hereinafter sometimes simply referred to as gloss), and normal temperature and high humidity. From the viewpoint of the durability of the toner (hereinafter, sometimes simply referred to as durability), and the viewpoint that the effects of Step 1-2 and Step 1-3 are significant, at least the aromatic dicarboxylic acid compound and the carbon number of 2 One type selected from -6 aliphatic dicarboxylic acid compounds is used. As other carboxylic acid components, for example, trivalent or higher aromatic polyvalent carboxylic acid compounds can be used.
In the present invention, carboxylic acids, acid anhydrides thereof, derivatives thereof such as alkyl (carbon number 1 to 3) esters, and the like are collectively referred to as carboxylic acid compounds.
The aromatic dicarboxylic acid compound also includes an aromatic dicarboxylic acid derivative that can become the same structural unit as the structural unit derived from the aromatic dicarboxylic acid by a condensation reaction. Specific examples of the aromatic dicarboxylic acid compound preferably include aromatic dicarboxylic acids such as phthalic acid, isophthalic acid and terephthalic acid, anhydrides of these acids, and alkyl (C1 to C3) esters thereof. Examples of the alkyl group in the alkyl ester include a methyl group, an ethyl group, a propyl group, and an isopropyl group. Among these, terephthalic acid or its alkyl (C1-C3) ester is preferable from the viewpoint of low-temperature fixability, glossiness and durability of the toner.
The content of the aromatic dicarboxylic acid compound is preferably 60 to 99 mol%, more preferably 70 to 99 mol%, still more preferably in the carboxylic acid component from the viewpoint of low-temperature fixability, glossiness and durability of the toner. 90 to 99 mol%.

Examples of the aliphatic dicarboxylic acid compound having 2 to 6 carbon atoms include oxalic acid, malonic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, succinic acid, adipic acid, etc .; dodecyl succinic acid, dodecenyl succinic acid, octenyl succinic acid Succinic acid substituted with an alkyl group having 1 to 20 carbon atoms such as an acid or an alkenyl group having 2 to 20 carbon atoms; anhydrides of these acids and alkyl (1 to 3 carbon atoms) esters of these acids It is done. Among these, from the viewpoint of low-temperature fixability, glossiness and durability of the toner, aliphatic dicarboxylic acid compounds having 4 to 6 carbon atoms, anhydrides of these acids, and alkyls of those acids (1 to 3 carbon atoms). Esters are preferred, fumaric acid and anhydrides thereof and alkyl (C1-3) esters are more preferred.
When an aliphatic dicarboxylic acid compound having 2 to 6 carbon atoms is used as the carboxylic acid component, the amount used is 60 to 100 mol% in the carboxylic acid component from the viewpoint of low-temperature fixability, glossiness and durability of the toner. Is preferable, 80-100 mol% is more preferable, and 90-100 mol% is still more preferable.
Examples of the trivalent or higher polyvalent carboxylic acid compound include aromatic carboxylic acids such as 1,2,4-benzenetricarboxylic acid (trimellitic acid), 2,5,7-naphthalenetricarboxylic acid, pyromellitic acid, and the like. Derivatives such as acid anhydrides and alkyl (carbon number 1 to 3) esters. Of the trivalent or higher polyvalent carboxylic acid compounds, trimellitic acid and its acid anhydride are preferable from the viewpoint of being inexpensive and easy to control the reaction.
When a trivalent or higher polyvalent carboxylic acid compound is also used as the carboxylic acid component, the amount used is 0.1 to 30 mol% in the carboxylic acid component from the viewpoint of low-temperature fixability, glossiness and durability of the toner. Is preferable, 1-25 mol% is more preferable, and 5-25 mol% is still more preferable.

When an aromatic dicarboxylic acid compound is used as the carboxylic acid component, the aliphatic diol having 2 to 10 carbon atoms and the aromatic dicarboxylic acid compound in the total number of moles of the alcohol component and the carboxylic acid component, which are raw material monomers of the crystalline polyester Is preferably 75 to 100 mol%, more preferably 80 to 97 mol%, from the viewpoint of low-temperature fixability, glossiness and durability of the toner.
Further, when an aliphatic dicarboxylic acid compound having 2 to 6 carbon atoms is used as the carboxylic acid component, the fatty acid having 2 to 10 carbon atoms in the total number of moles of the alcohol component and the carboxylic acid component which are raw material monomers of the crystalline polyester The total number of moles of the group diol and the aliphatic dicarboxylic acid compound having 2 to 6 carbon atoms is preferably 75 to 100 mol%, more preferably 80 to 100 mol, from the viewpoint of low-temperature fixability, glossiness and durability of the toner. %, More preferably 90 to 100 mol%.
There is no particular limitation on the molar ratio of the carboxylic acid component to the alcohol component (carboxylic acid component / alcohol component). However, when the crystalline polyester is to have a high molecular weight, it is preferable that the alcohol component is larger than the carboxylic acid component. Preferably, in a vacuum reaction, 0.9 or more and less than 1 are preferable, and 0.95 or more and less than 1 are more preferable from the viewpoint that the molecular weight of the resin can be easily adjusted by distilling off the alcohol component.
Furthermore, in step 1-1, (i) a raw material monomer of a styrene resin, and (ii) an amphoteric monomer capable of reacting with both the raw material monomer of the styrene resin and the alcohol component is added to the reaction system. Thus, the crystalline polyester can be made into a composite resin by subjecting it to an addition polymerization reaction in addition to the condensation polymerization reaction.

(Condensation polymerization reaction)
In step 1-1, the alcohol component and the carboxylic acid component are subjected to a condensation polymerization reaction. The polycondensation reaction between the alcohol component and the carboxylic acid component is preferably performed in the presence of an esterification catalyst. From the viewpoint of obtaining a crystalline polyester having a high storage modulus, it is performed in the presence of an esterification catalyst and a pyrogallol compound. It is more preferable.
Examples of the esterification catalyst suitably used for the polycondensation include a titanium compound and a tin (II) compound having no Sn—C bond, and these can be used alone or in combination.
As a titanium compound, the titanium compound which has a Ti-O bond is preferable, and the compound which has a C1-28 total carbon number alkoxy group, an alkenyloxy group, or an acyloxy group is more preferable.

Specific examples of titanium compounds include titanium diisopropylate bistriethanolamate [Ti (C ₆ H ₁₄ O ₃ N) ₂ (C ₃ H ₇ O) ₂ ], titanium diisopropylate bisdiethanolamate [Ti (C ₄ H ₁₀ O ₂ N) ₂ (C ₃ H ₇ O) ₂ ], titanium dipentylate bistriethanolamate [Ti (C ₆ H ₁₄ O ₃ N) ₂ (C ₅ H ₁₁ O) ₂ ], titanium diety rate bis triethanolaminate _{[Ti (C 6 H 14 O 3} N) 2 (C 2 H 5 O) 2 ], titanium dihydroxy octylate bis triethanolaminate _{[Ti (C 6 H 14 O 3} N) 2 (OHC 8 H ₁₆ O) ₂ ], titanium distearate bistriethanolamate [Ti (C ₆ H ₁₄ O ₃ N) ₂ (C ₁₈ H ₃₇ O) ₂ ], titanium triisopropylate triethanolamate [Ti (C _{6 H 14 O 3 N) 1 (} C 3 ₇ O) _3], and titanium monopropylate tris (triethanolaminate) _{[Ti (C 6 H 14 O 3} N) 3 (C 3 H 7 O) 1 ], and the like. Among these, titanium diisopropylate bistriethanolaminate, titanium diisopropylate bisdiethanolamate, and titanium dipentylate bistriethanolamate are preferable, and these are also available as, for example, commercial products of Matsumoto Trading Co., Ltd. It is.

Specific examples of other preferable titanium compounds include tetra-n-butyl titanate [Ti (C ₄ H ₉ O) ₄ ], tetrapropyl titanate [Ti (C ₃ H ₇ O) ₄ ], tetrastearyl titanate [Ti ( C ₁₈ H ₃₇ O) ₄ ], tetramyristyl titanate [Ti (C ₁₄ H ₂₉ O) ₄ ], tetraoctyl titanate [Ti (C ₈ H ₁₇ O) ₄ ], dioctyl dihydroxyoctyl titanate [Ti (C ₈ H ₁₇ O) ₂ (OHC ₈ H ₁₆ O) ₂ ], dimyristyl dioctyl titanate [Ti (C ₁₄ H ₂₉ O) ₂ (C ₈ H ₁₇ O) ₂ ] and the like. Among these, tetrastearyl titanate, tetramyristyl titanate, tetraoctyl titanate, and dioctyl dihydroxyoctyl titanate are preferable, and these can be obtained by reacting, for example, titanium halide with a corresponding alcohol. It is also available as a commercial product such as

Examples of the tin (II) compound having no Sn—C bond include a tin (II) compound having a Sn—O bond, a tin (II) compound having a Sn—X (X represents a halogen atom) bond, and the like. Preferred examples include tin (II) compounds having a Sn-O bond.
Examples of tin (II) compounds having a Sn-O bond include tin (II) oxalate, tin (II) diacetate, tin (II) dioctanoate, tin (II) dilaurate, tin (II) distearate, and Tin (II) carboxylate having a carboxylic acid group having 2 to 28 carbon atoms such as tin (II) dioleate; dioctyloxytin (II), dilauroxytin (II), distearoxytin (II), and dioleoxytin (II) Dialkoxytin (II) having an alkoxy group having 2 to 28 carbon atoms, such as tin oxide (II) and tin sulfate (II).

Examples of the compound having a Sn-X (X represents a halogen atom) bond include tin (II) halides such as tin (II) chloride and tin (II) bromide. Among them, fatty acid tin represented by (R ¹ COO) ₂ Sn (wherein R ¹ represents an alkyl group or alkenyl group having 5 to 19 carbon atoms) from the standpoint of charge rising effect and catalytic ability. (II), represented by (R ² O) ₂ Sn (wherein R ² represents an alkyl group or alkenyl group having 6 to 20 carbon atoms) and represented by SnO Tin (II) oxide is preferred, fatty acid tin (II) and tin (II) oxide represented by (R ¹ COO) ₂ Sn are more preferred, tin (II) dioctanoate, tin (II) distearate, and oxidation More preferred is tin (II).
The said titanium compound and a tin (II) compound can be used 1 type or in combination of 2 or more types.
The amount of the esterification catalyst is preferably 0.01 to 1 part by weight, more preferably 0.1 to 0.6 part by weight, based on 100 parts by weight of the total amount of the alcohol component and the carboxylic acid component.

The pyrogallol compound has a benzene ring in which three hydrogen atoms adjacent to each other are substituted with a hydroxyl group, and pyrogallol, gallic acid, gallic acid ester, 2,3,4-trihydroxybenzophenone, 2,2 Examples include benzophenone derivatives such as', 3,4-tetrahydroxybenzophenone, and catechin derivatives such as epigallocatechin and epigallocatechin gallate.
The abundance of the pyrogallol compound in the condensation polymerization reaction is preferably 0.001 to 1 part by weight with respect to 100 parts by weight of the total amount of the alcohol component and the carboxylic acid component subjected to the condensation polymerization reaction, and 0.005 to 0.4. Part by weight is more preferable, and 0.01 to 0.2 part by weight is still more preferable. Here, the abundance of the pyrogallol compound means the total amount of the pyrogallol compound subjected to the condensation polymerization reaction.
The weight ratio of the pyrogallol compound and the esterification catalyst (pyrogallol compound / esterification catalyst) is preferably 0.01 to 0.5, more preferably 0.03 to 0.3, from the viewpoint of the durability of the resin. More preferably, it is 05-0.2.

The polycondensation reaction between the alcohol component and the carboxylic acid component can be performed in an inert gas atmosphere in the presence of an esterification catalyst such as a tin compound or a titanium compound, a polymerization inhibitor, and the like. -250 degreeC is preferable, and 180-250 degreeC is preferable as final ultimate temperature, and 190-230 degreeC is more preferable.
Specifically, for example, all raw material monomers are charged at once in order to increase the strength of the resin, or divalent raw material monomers are first reacted to reduce low molecular weight components, and then trivalent or higher raw material monomers are added. And reacting them may be used. Further, the reaction may be accelerated by reducing the pressure of the reaction system in the latter half of the polymerization.
The end point of the polycondensation reaction is when the crystalline polyester is taken out from the reaction tank when it is finished in a reaction tank that does not use a stirrer, and when it is finished in the reaction tank that uses a stirrer, stirring is substantially performed. It ’s time to stop. In addition, the stirring speed during the condensation polymerization reaction is preferably about 50 to 1000 rpm, more preferably about 100 to 500 rpm.

<Step 1-2>
Step 1-2 is a step of cooling the polyester obtained in Step 1-1 until the temperature becomes 50 ° C. or lower. From the viewpoint of low-temperature fixability, glossiness and durability of the toner, it is preferably cooled to 45 ° C. or lower, more preferably 40 ° C. or lower. By this cooling operation, spherulites can be sufficiently precipitated. If the cooling is insufficient, the precipitation of spherulites becomes insufficient and the low-temperature fixability, glossiness and durability of the toner are reduced. For the cooling step, a cooling method such as air cooling or water cooling can be used. In the actual machine, a cooling device such as a steel belt cooler (manufactured by Nippon Belting Co., Ltd., Sandvik Co., Ltd.) or a drum cooler (manufactured by Ryoka Techno Co., Ltd., Mitsui Miike Kako Co., Ltd.) may be used.
In order to sufficiently precipitate the spherulites, it is preferable that the cooling time from the temperature at the end of the polycondensation reaction of the crystalline polyester to 50 ° C. is 1 to 24 hours as a guideline. From the viewpoint of property and durability, it is more preferably 3 to 18 hours, and further preferably 5 to 12 hours. If the cooling time taken to reach 50 ° C. is in the above range, crystallization (spheroidization) proceeds sufficiently, and the low-temperature fixability, glossiness and durability of the toner are improved. The cooling rate is preferably 5 to 100 ° C./hour, more preferably 10 to 85 ° C./hour, further preferably 15 to 60 ° C./hour, and still more preferably 15 to 45 ° C./hour. It is preferable to cool at a constant rate, and during the cooling operation, the slowness of the cooling rate is within ± 20 ° C / hour (preferably within ± 10 ° C / hour, more preferably within ± 5 ° C / hour). And more preferably within the range of ± 3 ° C./hour).
From the viewpoint of low-temperature fixability, glossiness and durability of the toner, after step 1-2, until heat treatment step 1-3 described later is performed (hereinafter referred to as “transition from step 1-2 to step 1-3). For a period of 12 hours or more, preferably 1 day or more, more preferably 1 to 30 days, still more preferably 1 to 7 days, and even more preferably 3 to 7 days. -2 is allowed to stand at the temperature after cooling (50 ° C. or less), preferably 0 to 45 ° C., more preferably 5 to 35 ° C., and still more preferably 5 to 30 ° C. Since the crystallization proceeds even after the crystalline polyester is cooled in the step 1-2, the time required for the transition from the step 1-2 to the step 1-3 is provided, and the heat treatment is performed after the crystallization has sufficiently progressed. Is preferable from the above viewpoint.

<Step 1-3>
Step 1-3 is a temperature exceeding 50 ° C. of the crystalline polyester cooled in Step 1-2, and is “endothermic maximum peak temperature (° C.) − 60 ° C.” to “endothermic maximum peak temperature (° C.)”. This is a process of heat treatment at -5 ° C. The heat treatment is performed with substantially crystalline polyester. Here, the maximum peak temperature of the endotherm is that the crystalline polyester cooled in the step 1-2 is cooled to room temperature (20 ° C.), and a differential scanning calorimeter (DSC) is used under the conditions described in the examples. It is a measured value. The maximum endothermic peak temperature (° C.) is a temperature measured at the time required for the transition from Step 1-2 to Step 1-3, and is essential due to a change in the time required for the transition from Step 1-2 to Step 1-3. Does not change.
The viewpoint of heating temperature is to uniformize the spherulites and reduce the variation in the particle size with respect to the variation in the degree of neutralization when the aqueous dispersion is made, and to reduce the variation coefficient (CV value) of the particle size distribution of the crystalline polyester particles, In addition, from the viewpoint of low-temperature fixability, glossiness, and durability of the toner, preferably, “maximum endothermic peak temperature (° C.) − 55 ° C.” to “maximum endothermic peak temperature (° C.) − 10 ° C.”, more preferably “ Endothermic maximum peak temperature (° C) -50 ° C "to" endothermic maximum peak temperature (° C) -13 ° C ", more preferably" endothermic maximum peak temperature (° C) -45 ° C "to" endothermic maximum peak temperature " (° C.) − 15 ° C. ”, more preferably“ maximum endothermic peak temperature (° C.) − 35 ° C. ”to“ maximum endothermic peak temperature (° C.) − 20 ° C. ”.

The heat treatment time is preferably from 0.5 to 48 hours, more preferably from 1 to 24 hours, further preferably from 3 to 18 hours, and from 5 to 15 hours from the viewpoint of low-temperature fixability, glossiness and durability of the toner. Even more preferred. If the heat treatment time is within this range, spherulites are considered to be uniform.
An oven or the like can be used for the heat treatment in Step 1-3. For example, when an oven is used, the polyester obtained in step 1-2 can be placed in the oven as it is and kept at the above temperature, whereby the heat treatment can be easily performed.
By performing step 1-3 in addition to step 1-2, coarse particles in the crystalline polyester are reduced, and spherulites having a uniform size can be obtained.

(Physical properties of crystalline polyester)
The crystalline polyester obtained as described above is useful as a crystalline polyester for toner. The physical properties of the crystalline polyester of the present invention are as follows.
The number average molecular weight of the crystalline polyester of the present invention is not particularly limited, but is usually preferably 1,000 or more, more preferably 1,500 or more. However, considering the productivity of the crystalline polyester, the number average molecular weight is preferably 6,000 or less, more preferably 5,000 or less, and further preferably 4,000 or less. From the above viewpoint, the number average molecular weight of the crystalline polyester of the present invention is preferably 1,000 to 6,000, more preferably 1,000 to 5,000, and still more preferably 1,500 to 4,000.
Further, the weight average molecular weight is preferably 3,000 or more, more preferably 5,000 or more, still more preferably 8,000 or more, preferably 100,000 or less, more preferably from the same viewpoint as the number average molecular weight. Is 50,000 or less, more preferably 30,000 or less, and still more preferably 20,000 or less. From the above viewpoint, the crystalline polyester of the present invention preferably has a weight average molecular weight of 3,000 to 100,000, more preferably 5,000 to 50,000, still more preferably 5,000 to 30,000, 000 to 20,000 is even more preferable.
In the present invention, the number average molecular weight and the weight average molecular weight of the crystalline polyester are both values obtained by measuring the chloroform-soluble content.

The softening point of the crystalline polyester obtained by the present invention is preferably 80 to 160 ° C., more preferably 80 to 140 ° C., and 90 to 130 ° C. from the viewpoints of low-temperature fixability, glossiness and durability of the toner. More preferably, 100-120 degreeC is still more preferable.
The melting point of the crystalline polyester obtained by the present invention is preferably 60 to 130 ° C., more preferably 75 to 120 ° C., still more preferably 90 to 110 ° C., from the viewpoints of low-temperature fixability, glossiness and durability of the toner. is there.
The acid value of the crystalline polyester is preferably 1 to 40 mgKOH / g, more preferably 2 to 35 mgKOH / g, and more preferably 3 to 30 mgKOH / g from the viewpoint of improving the dispersion of the crystalline polyester in the aqueous dispersion. Further preferred.
The number average molecular weight, softening point, melting point, and acid value can be easily adjusted by adjusting the raw material monomer composition, the polymerization initiator, the molecular weight, the catalyst amount, etc., or by selecting the reaction conditions.

(Amorphous resin)
In the production of the electrophotographic toner of the present invention described later, it is preferable to use an amorphous resin together with the crystalline polyester from the viewpoints of low-temperature fixability, glossiness and durability of the toner.
The amorphous resin is preferably a condensation polymerization resin obtained by condensation polymerization of an alcohol component and a carboxylic acid component. In the present invention, the amorphous resin comprises an alcohol component containing 70 mol% or more of an alkylene oxide adduct of bisphenol A represented by the above formula (I) and / or an aliphatic diol having 2 to 10 carbon atoms and a carboxylic acid. A polyester resin obtained by polycondensation with an acid component is preferred.

-Alcohol component-
The total content of the alkylene oxide adduct of bisphenol A and / or the aliphatic diol having 2 to 10 carbon atoms is preferably 70 mol% or more, more preferably 80 to 100 mol%, still more preferably 90% in the alcohol component. ˜100 mol%. As the aliphatic diol having 2 to 10 carbon atoms, an aliphatic diol having 2 to 5 carbon atoms is preferable, and 1,2-propanediol is more preferable. The use of an alkylene oxide adduct of bisphenol A improves environmental stability.
Examples of the alcohol other than the alkylene oxide adduct of bisphenol A that can be contained in the alcohol component include trivalent or higher alcohols similar to those used for the crystalline polyester.

-Carboxylic acid component-
The carboxylic acid component of the amorphous resin has the same fragrance as that described as the carboxylic acid component used in the crystalline polyester from the viewpoint of enhancing the compatibility between the amorphous resin and the crystalline polyester and the gloss. It is preferable to contain a group dicarboxylic acid compound, and it is more preferable to contain a terephthalic acid compound. Note that an amorphous resin obtained using a terephthalic acid compound as a carboxylic acid component and an amorphous resin obtained without using a terephthalic acid compound may be prepared and used in combination.
When the aromatic dicarboxylic acid compound is contained, the content thereof is preferably 30 to 95 mol%, more preferably 40 to 90 mol%, still more preferably 50 to 85 mol% in the carboxylic acid component. In the case where an amorphous resin obtained using a terephthalic acid compound as a carboxylic acid component and an amorphous resin obtained without using a terephthalic acid compound are prepared and used in combination, terephthalic acid is used. The ratio of the amorphous resin obtained using the compound as the carboxylic acid component to the amorphous resin obtained without using the terephthalic acid compound (the former / the latter) is 1/3 to 3 / 1 is preferable, 1/2 to 3/1 is more preferable, and 1/1 to 2/1 is still more preferable.

Examples of the divalent carboxylic acid that can be used other than the aromatic dicarboxylic acid compound include oxalic acid, malonic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, succinic acid, adipic acid, etc. An aliphatic dicarboxylic acid having 10 (preferably 4 to 10 carbon atoms, more preferably 4 to 8 carbon atoms); an alkyl group having 1 to 20 carbon atoms such as dodecyl succinic acid, dodecenyl succinic acid, octenyl succinic acid, or 2 to 20 carbon atoms And succinic acid substituted with an alkenyl group of the above; anhydrides of these acids and alkyl (carbon number 1 to 3) esters of these acids.
When the aliphatic dicarboxylic acid having 2 to 10 carbon atoms is contained, the content thereof is preferably 30 to 90 mol%, more preferably 40 to 85 mol%, still more preferably 50 to 75 mol in the carboxylic acid component. %. When the succinic acid substituted with the alkyl group having 1 to 20 carbon atoms or the alkenyl group having 2 to 20 carbon atoms is contained, the content thereof is preferably 3 to 30 mol%, more preferably in the carboxylic acid component. It is 5-20 mol%, More preferably, it is 5-15 mol%.
Examples of trivalent or higher polyvalent carboxylic acid compounds other than aromatic dicarboxylic acid compounds that can be used include the same compounds as those used for the crystalline polyester.
When the trivalent or higher polyvalent carboxylic acid compound is contained, the content thereof is preferably 3 to 40 mol%, more preferably 5 to 35 mol%, still more preferably 5 to 30 mol% in the carboxylic acid component. is there.

(Physical properties of amorphous resin)
The number average molecular weight of the amorphous resin is preferably 1,000 to 6,000, and more preferably 2,000 to 5,000. The weight average molecular weight is preferably 10,000 or more, more preferably 30,000 or more, and preferably 1,000,000 or less. The number average molecular weight and the weight average molecular weight of the amorphous resin are both values obtained by measuring the tetrahydrofuran soluble content.
The softening point of the amorphous resin is preferably 70 to 180 ° C, more preferably 90 to 150 ° C, from the viewpoint of low-temperature fixability. The amorphous resin used in the present invention is obtained by using a resin having a high softening point (hereinafter referred to as a high softening point resin) and a resin having a low softening point (hereinafter referred to as a low softening point resin) in combination. It is more excellent in terms of low-temperature fixability, glossiness and durability. When the high softening point resin and the low softening point resin are used in combination, one or both of them may be used.
Specifically, the softening point of the high softening point resin is preferably 110 to 150 ° C, and the softening point of the low softening point resin is preferably 90 ° C or higher and lower than 110 ° C. The softening point of the high softening point resin used in combination and the softening point of the low softening point resin are preferably different by 10 ° C. or more, more preferably 15 to 40 ° C.
When the high softening point resin and the low softening point resin are used in combination, the weight ratio of the high softening point resin to the low softening point resin (high softening point resin / low softening point resin) is preferably 1/3 to 3/1. / 3 to 2/1 is more preferable, and 1/2 to 1/1 is still more preferable.

The Tg of the amorphous resin is preferably 45 to 80 ° C., more preferably 55 to 75 ° C. from the viewpoint of low-temperature fixability.
The acid value of the amorphous resin is preferably 1 to 40 mgKOH / g, more preferably 2 to 35 mgKOH / g, and more preferably 3 to 30 mgKOH / g from the viewpoint of improving the dispersion of the amorphous resin in the aqueous dispersion. g is more preferable.
The number average molecular weight, softening point, Tg, and acid value can be easily adjusted by adjusting the raw material monomer composition, the polymerization initiator, the molecular weight, the catalyst amount, etc., or by selecting the reaction conditions.

(Modified amorphous resin)
The amorphous resin used in the present invention includes a modified amorphous resin.
Examples of the modified amorphous resin include a urethane-modified polyester in which the resin is modified with a urethane bond, an epoxy-modified polyester in which the polyester is modified with an epoxy bond, and a hybrid resin having two or more resins including a polyester component. Can be mentioned.
As the amorphous resin, either one of the polyester resin and the modified amorphous resin may be used in combination. Specifically, the polyester and / or a hybrid having a polyester and a styrene resin may be used. Resin may be used.

[Method for producing binder resin for toner]
There is no particular limitation on the method for producing the binder resin for toner of the present invention (hereinafter sometimes simply referred to as a binder resin), but an aqueous dispersion containing crystalline polyester and an aqueous dispersion containing an amorphous resin; Is obtained by subjecting to an aggregation step and a coalescence step. Specifically, it can be obtained by a production method including the following steps 1 to 4.

Step 1: (Step 1-1) An alcohol component containing an aliphatic diol having 2 to 10 carbon atoms, a carboxyl containing at least one selected from an aromatic dicarboxylic acid compound and an aliphatic dicarboxylic acid compound having 2 to 6 carbon atoms After subjecting the acid component to a polycondensation reaction, (step 1-2), after cooling to 50 ° C. or lower, (step 1-3) a temperature exceeding 50 ° C., “the maximum peak temperature of endotherm (° C. ) −60 ° C. ”to“ Maximum endothermic peak temperature (° C.) −5 ° C. ”to obtain crystalline polyester.
Step 2: A step of obtaining an aqueous dispersion containing the crystalline polyester obtained in Step 1.
Step 3: A step of obtaining an aqueous dispersion of aggregated particles by mixing the aqueous dispersion containing the crystalline polyester obtained in Step 2 with an aqueous dispersion containing an amorphous resin and then subjecting to an aggregation step.
Step 4: A step of obtaining an aqueous dispersion of coalesced particles by subjecting the aqueous dispersion of aggregated particles obtained in Step 3 to an coalescence step.

The weight ratio of the crystalline polyester to the amorphous resin (crystalline polyester / amorphous resin) in the binder resin is 5/95 to 50 / from the viewpoint of low-temperature fixability, glossiness and durability of the toner. 50 is preferable, 10/90 to 40/60 is more preferable, and 15/85 to 35/65 is still more preferable.
Furthermore, the crystalline polyester, the amorphous resin, and the binder resin containing these are preferably excellent in solubility in an organic solvent.
The acid value of the binder resin obtained by the above production method is preferably 1 to 40 mgKOH / g, more preferably 2 to 35 mgKOH / g, and more preferably 3 to 30 mgKOH / g from the viewpoints of chargeability and hydrolysis resistance of the toner. Further preferred.

The electrophotographic toner of the present invention containing the binder resin is a known toner binder resin different from the binder resin, for example, polyester, styrene-acrylic resin, etc., as long as the effects of the present invention are not impaired. The resin may contain a styrene resin, epoxy resin, polycarbonate, polyurethane, or the like.
In the electrophotographic toner of the present invention, the content of the binder resin obtained by the method for producing the binder resin for toner of the present invention is preferably 50% by weight or more, more preferably 70% by weight or more in the total binder resin. It is preferably 80% by weight or more, more preferably 90% by weight or more, and still more preferably 100% by weight.
Hereafter, the said process 1-the process 4 regarding the manufacturing method of the binder resin for toners of this invention are demonstrated in order.

[Step 1]
Step 1 is a step having Step 1-1, Step 1-2, and Step 1-3, and these steps are the same as described above. The crystalline polyester obtained in Step 1 is used in Step 2 described later.
[Step 2]
Step 2 is a step of obtaining an aqueous dispersion containing the crystalline polyester obtained in Step 1. In the description of Step 2, a method for obtaining an aqueous dispersion containing the amorphous resin used in Step 3 will also be described.
In the present specification, “aqueous” may contain a solvent such as an organic solvent, but water is preferably 50% by weight or more, preferably 70% by weight or more, more preferably 90% by weight or more. Preferably it contains 99% by weight or more. Further, hereinafter, when simply described as “resin”, it refers to both crystalline polyester and amorphous resin.
The aqueous dispersion containing the crystalline polyester or the aqueous dispersion containing the amorphous resin is mixed with the crystalline polyester or the amorphous resin, the organic solvent and water, and further, if necessary, a neutralizing agent or a surfactant. After stirring, the organic solvent is removed by distillation or the like. Preferably, the crystalline polyester or amorphous resin and, if necessary, the surfactant are dissolved in an organic solvent, and then water and, if necessary, a neutralizing agent are mixed. In addition, when stirring a mixture, generally used mixing stirring apparatuses, such as an anchor wing | blade, can be used.
When an aqueous dispersion is produced using the crystalline polyester obtained in the present invention, the volume-median particle size of the obtained crystalline polyester particles (spherulites) varies with respect to fluctuations in the degree of neutralization by the neutralizing agent. It is small and has a small coefficient of variation (CV value) in the particle size distribution of the crystalline polyester particles. As a result, the electrophotographic toner of the present invention containing a binder resin obtained by using the crystalline polyester is excellent in low-temperature fixability, glossiness and durability.

Examples of the organic solvent include alcohol solvents such as ethanol, isopropanol, and isobutanol; ketone solvents such as acetone, 2-butanone, methyl ethyl ketone, methyl isobutyl ketone, and diethyl ketone; ether solvents such as dibutyl ether, tetrahydrofuran, and dioxane. Solvent; ethyl acetate is mentioned. Among these, ethyl acetate and 2-butanone are preferable from the viewpoints of dispersibility, gloss and durability of the crystalline polyester.
Examples of the neutralizing agent include alkali metals such as lithium hydroxide, sodium hydroxide, and potassium hydroxide; organic bases such as ammonia, trimethylamine, ethylamine, diethylamine, triethylamine, triethanolamine, and tributylamine.
Examples of the surfactant include anionic surfactants such as sulfate ester, sulfonate, phosphate ester, and soap (such as alkyl ether carboxylate); amine salt type, quaternary ammonium salt Examples include cationic surfactants such as molds; nonionic surfactants described later. When using a surfactant, the amount used is preferably 0.1 to 20 parts by weight, more preferably 0.5 to 10 parts by weight, based on 100 parts by weight of the crystalline polyester or amorphous resin. .

The amount of the organic solvent used when mixing with the crystalline polyester or amorphous resin is preferably 100 to 1,000 parts by weight with respect to 100 parts by weight of the crystalline polyester or amorphous resin. The amount of water used when mixing with the crystalline polyester or amorphous resin is preferably 100 to 1,000 parts by weight with respect to 100 parts by weight of the organic solvent.
30-90 degreeC is preferable and, as for the temperature at the time of mixing (dissolving) crystalline polyester or an amorphous resin with an organic solvent, 40-80 degreeC is more preferable. The temperature at which the crystalline polyester is mixed (dissolved) with the organic solvent is higher than the temperature at which the amorphous resin is mixed (dissolved) with the organic solvent from the viewpoint of solubility and gloss (preferably 10 ° C. Higher).
The solid content concentration of the aqueous dispersion containing the crystalline polyester and the aqueous dispersion containing the amorphous resin is preferably 3 to 50% by weight, more preferably 5 to 30% by weight, by adding water as appropriate. Preferably, it is adjusted to 7 to 15% by weight.

Moreover, it can also be set as a dispersion liquid, without using the said organic solvent. This is because when the resin is mixed with a nonionic surfactant, the viscosity of the resulting mixture decreases, and the decrease in the viscosity of the mixture is compatible with the nonionic surfactant, This is because the softening point of the resin apparently decreases. By utilizing this phenomenon, the apparent softening point of a resin compatible with a nonionic surfactant can be lowered to the boiling point of water or less, and even a resin having a melting point or softening point of 100 ° C. or higher by itself. By dropping water at normal pressure, a dispersion in which the resin is dispersed in water can be obtained.
This method requires at least water and a nonionic surfactant, so it can be applied to resins that are insoluble in organic solvents, and does not require the burden of equipment for recovering organic solvents and maintaining the work environment. Since a special device required when using mechanical means is not required, there is an advantage that a resin particle dispersion can be produced economically.

  Examples of the nonionic surfactant include polyoxyethylene alkylaryl ethers such as polyoxyethylene nonylphenyl ether; polyoxyethylene alkyl ethers such as polyoxyethylene oleyl ether and polyoxyethylene lauryl ether; polyoxy Polyoxyethylene sorbitan esters such as ethylene sorbitan monolaurate and polyoxyethylene sorbitan monostearate; polyoxyethylene fatty acids such as polyethylene glycol monolaurate, polyethylene glycol monostearate, and polyethylene glycol monooleate Examples of esters include oxyethylene / oxypropylene block copolymers. In addition, an anionic surfactant or a cationic surfactant may be used in combination with the nonionic surfactant.

  As the nonionic surfactant, it is preferable to select a nonionic surfactant having good compatibility with the resin. In order to obtain a stable resin dispersion, the HLB of the nonionic surfactant is preferably 12 to 18, and two or more different HLB nonionic surfactants are used depending on the type of resin. It is more preferable. For example, in the case of a highly hydrophilic resin, at least one nonionic surfactant having an HLB of 12 to 18 may be used. In the case of a highly hydrophobic resin, a low HLB, for example, 7 to 10 is used. It is preferable to adjust the weighted average of both HLBs to 12 to 18 by using those having the same level and those having a high HLB, for example, 14 to 20 in combination. In this case, it is presumed that those having an HLB of about 7 to 10 can compatibilize the resin, and those having a high HLB can stabilize the dispersion of the resin in water.

The clouding point of the nonionic surfactant is preferably 70 to 105 ° C, more preferably 80 to 105 ° C when the resin is atomized under normal pressure and water.
The amount of the nonionic surfactant used is preferably 5 parts by weight or more based on 100 parts by weight of the crystalline polyester or amorphous resin from the viewpoint of lowering the melting point of the resin, and the nonionic surfactant remaining in the toner. From the viewpoint of controlling the agent, 80 parts by weight or less is preferable. Therefore, from the viewpoint of making these compatible, the amount of the nonionic surfactant used is preferably 5 to 80 parts by weight and more preferably 10 to 70 parts by weight with respect to 100 parts by weight of the crystalline polyester or amorphous resin. 20 to 60 parts by weight is preferable.

Volume median particle size of crystalline polyester particles in an aqueous dispersion containing crystalline polyester, and volume median particle size of amorphous resin particles in an aqueous dispersion containing amorphous resin (both neutralization degrees) 95%) is preferably 50 to 1,000 nm, more preferably 50 to 500 nm, still more preferably 50 to 300 nm, and even more preferably 80 to 200 nm, from the viewpoint of uniformly agglomerating in Step 3. The volume median particle size of each particle can be measured with a laser diffraction type particle size measuring machine or the like, and so on.
Further, the coefficient of variation (CV value) of the particle size distribution of the crystalline polyester particles in the aqueous dispersion is preferably 50% or less, more preferably 37% or less, from the viewpoint of low-temperature fixability, gloss and durability of the toner. More preferably, it is 30% or less, more preferably 28% or less, and still more preferably 25% or less. From the same viewpoint as described above, the CV value of the amorphous resin particles in the aqueous dispersion is preferably 50% or less, more preferably 37% or less, more preferably 30% or less, still more preferably 28% or less, and still more. Preferably it is 25% or less. The lower limit of the CV value is preferably 5% from the viewpoint of ease of production.

[Step 3]
Step 3 is a step of obtaining an aqueous dispersion of aggregated particles by mixing the aqueous dispersion containing the crystalline polyester obtained in Step 2 with an aqueous dispersion containing an amorphous resin and then subjecting to an aggregation step. It is.
In step 3, additives such as colorants, charge control agents, mold release agents, conductivity modifiers, extender pigments, reinforcing fillers such as fibrous substances, antioxidants, and antioxidants are further added. Then, it may be subjected to an aggregation step. The additive can also be used as an aqueous dispersion.

  There is no restriction | limiting in particular as a coloring agent, A well-known coloring agent is mentioned, According to the objective, it can select suitably. Specifically, carbon black, inorganic composite oxide, chrome yellow, hansa yellow, benzidine yellow, selenium yellow, quinoline yellow, permanent orange GTR, pyrazolone orange, vulcan orange, watch young red, permanent red, brilliantamine 3B, Brilliantamine 6B, Dupont Oil Red, Pyrazolone Red, Resol Red, Rhodamine B Lake, Lake Red C, Bengal, Aniline Blue, Ultramarine Blue, Calco Oil Blue, Methylene Blue Chloride, Phthalocyanine Blue, Phthalocyanine Green, Malachite Green Oxalate, etc. Various pigments: acridine, xanthene, azo, benzoquinone, azine, anthraquinone, indico, Indigo dyes, phthalocyanine, aniline black, polymethine, triphenylmethane dyes, diphenylmethane dyes, thiazine, and include various dyes of thiazole, and the like. These can be used alone or in combination of two or more. When adding a coloring agent, the addition amount is preferably 0.1 to 20 parts by weight and more preferably 1 to 10 parts by weight with respect to 100 parts by weight of the total amount of the crystalline polyester and the amorphous resin.

  Examples of charge control agents include chromium azo dyes, iron azo dyes, aluminum azo dyes, and salicylic acid metal complexes. Various charge control agents may be used alone or in combination of two or more. When the charge control agent is added, the addition amount is preferably 0.1 to 8 parts by weight, more preferably 0.3 to 7 parts by weight with respect to 100 parts by weight of the total amount of the crystalline polyester and the amorphous resin. .

Release agents include fatty acid amides such as oleic acid amide, erucic acid amide, ricinoleic acid amide, and stearic acid amide; plant waxes such as carnauba wax, rice wax, candelilla wax, wood wax, and jojoba oil; Animal waxes such as beeswax; waxes such as mineral and petroleum waxes such as montan wax, ozokerite, ceresin, microcrystalline wax, and Fischer-Tropsch wax; polyolefin waxes, paraffin waxes and silicones. You may use a mold release agent individually by 1 type or in combination of 2 or more types. The melting point of the release agent is preferably from 60 to 140 ° C., more preferably from 60 to 100 ° C., from the viewpoint of low-temperature fixability and offset resistance of the toner.
In the case of adding a release agent, the addition amount is preferably 0.5 to 10 parts by weight from the viewpoint of dispersibility in the resin with respect to 100 parts by weight of the total amount of the crystalline polyester and the amorphous resin. 1-8 weight part is more preferable, and 1-7 weight part is still more preferable.
A preferable mixing weight ratio between the crystalline polyester and the amorphous resin is the same as the weight ratio shown in the above description regarding the binder resin for toner.
In the aggregation process, the solid content concentration in the system is preferably 5 to 50% by weight, more preferably 5 to 30% by weight, and still more preferably 5 to 20% by weight in order to cause uniform aggregation.

The pH in the system in the aggregation step is preferably 2 to 10, more preferably 2 to 9, and still more preferably 3 to 8, from the viewpoint of achieving both the dispersion stability of the mixed solution and the aggregation property of the resin particles.
From the same point of view, the temperature in the system in the aggregation process is not less than “softening point of binder resin−60 ° C.” (temperature lower by 60 ° C. than the softening point, the same shall apply hereinafter) and not more than the softening point of binder resin. Is preferred. In the present invention, since crystalline polyester and amorphous resin are used as the binder resin, the weighted average of the softening point of the crystalline polyester and the softening point of the amorphous resin is used as the softening point of the binder resin. (When two or more kinds of amorphous resins are used, the weighted average is similarly applied. The same applies hereinafter). Moreover, when using a masterbatch, the weighted average temperature including the resin used for it is made into the softening point of mixed resin.

In addition, additives such as a colorant and a charge control agent may be mixed in advance with crystalline polyester or amorphous resin when preparing resin particles, and each additive is separately dispersed in a dispersion medium such as water. A dispersion liquid prepared may be prepared, mixed with resin particles, and subjected to an aggregation step. When the additive is added to the crystalline polyester or amorphous resin in advance when preparing the resin particles, it is preferable to melt and knead the crystalline polyester or amorphous resin and the additive in advance.
For melt kneading, it is preferable to use an open roll type biaxial kneader. The open roll type twin-screw kneader is a kneader in which two rolls are arranged close to each other in parallel, and a heating function or a cooling function can be imparted by passing a heat medium through each roll. Therefore, the open roll type twin screw kneader is an open type part to be melt kneaded, and is provided with a heating roll and a cooling roll. The heat of kneading generated can be easily dissipated.

In the aggregation process, an aggregating agent can be added in order to effectively perform aggregation. As the flocculant, a quaternary salt cationic surfactant, polyethyleneimine, and the like are used in the organic system, and an inorganic metal salt, an inorganic ammonium salt, a divalent or higher metal complex, and the like are used in the inorganic system.
Examples of the inorganic metal salt include metal salts such as sodium sulfate, sodium chloride, calcium chloride, calcium nitrate, barium chloride, magnesium chloride, zinc chloride, aluminum chloride, and aluminum sulfate; polyaluminum chloride, polyaluminum hydroxide, and Examples thereof include inorganic metal salt polymers such as calcium polysulfide. Examples of the inorganic ammonium salt include ammonium sulfate, ammonium chloride, and ammonium nitrate.
When the flocculant is added, the addition amount is preferably 60 parts by weight or less, more preferably 55 parts by weight or less, and more preferably 50 parts by weight or less with respect to 100 parts by weight of the binder resin from the viewpoint of environmental resistance characteristics of the toner. Is more preferable.
The flocculant is preferably added after being dissolved in an aqueous medium, and is preferably sufficiently stirred at the time of addition of the flocculant and after completion of the addition.

In step 3, from the viewpoint of uniformly dispersing a mixture of an aqueous dispersion containing a crystalline polyester and an aqueous dispersion containing an amorphous resin and various additives used as necessary, it is preferably a binder. The dispersion treatment is performed at a temperature lower than the softening point of the resin, more preferably at a temperature not higher than “the softening point−30 ° C.”. Specifically, the temperature is preferably 65 ° C. or less, more preferably 55 ° C. or less, and the dispersion treatment should be performed at a temperature higher than 0 ° C. from the viewpoint of fluidity of the medium and production energy of the aqueous dispersion of the resin. Is preferable, and it is more preferable to carry out at 10 degreeC or more.
From these viewpoints, a uniform resin dispersion can be prepared by a usual method such as stirring at a temperature of preferably about 0 to 65 ° C., more preferably about 10 to 55 ° C.

  As a method of dispersion treatment, high-speed stirring such as Ultra Disper (trade name, manufactured by Asada Tekko Co., Ltd.), Ebara Milder (trade name, manufactured by Ebara Corporation), and TK Homomixer (trade name, manufactured by Primix Co., Ltd.) High pressure homogenizer (product name) manufactured by Izumi Food Machinery Co., Ltd., homovalve type high pressure homogenizer represented by Minilab 8.3H type (product name manufactured by Rannie); Microfluidizer (product name manufactured by Microfluidics) ) And Nanomizer (trade name, manufactured by Nanomizer Co., Ltd.) and the like.

  The volume median particle size of the agglomerated particles obtained in step 3 is preferably 1 to 10 μm, more preferably 2 to 8 μm, and more preferably 3 to 7 μm from the viewpoint of uniformly coalescing in subsequent step 4 to produce toner particles. Further preferred.

[Step 4]
In Step 4, after adding an aggregation terminator to the aqueous dispersion of aggregated particles obtained in Step 3 as necessary, the aggregated particles in the aqueous dispersion are coalesced by being subjected to a coalescence step, This is a step of obtaining an aqueous dispersion of coalesced particles.
In step 4, the aggregated particles obtained in step 3 can be united by heating.
The temperature in the system in the step 4 is not less than “softening point of binder resin−30 ° C.” or more and “the softening point + 10” from the viewpoint of the target particle size, particle size distribution, shape control and particle fusing property. "Softening point-25 ° C" or higher, "softening point + 10 ° C" or lower, more preferably "softening point-20 ° C" or higher, and "softening point + 10 ° C" or lower. The stirring speed is preferably a speed at which the aggregated particles do not settle. Specifically, it is preferably 70 to 100 ° C, more preferably 70 to 90 ° C.
In addition, when using an aggregation terminator, it is preferable to use a surfactant as the aggregation terminator, and it is more preferable to use an anionic surfactant. Of the anionic surfactants, it is more preferable to use at least one selected from the group consisting of alkyl ether sulfates, alkyl sulfates, and linear alkylbenzene sulfonates.

In the present invention, in the toner for electrophotography, the core portion includes the crystalline polyester and the amorphous resin, and the shell portion is the amorphous resin, and includes “core shell particles” as a binder resin. There may be. The core part is a resin obtained by subjecting an aqueous dispersion containing an aqueous dispersion containing the crystalline resin and an aqueous dispersion containing the amorphous resin to an agglomeration step, as in Step 3. Is preferred.
In the electrophotographic toner containing the core-shell particles, the step of mixing the aqueous dispersion of the aggregated particles obtained in Step 3 with the aqueous dispersion containing the amorphous resin before the above-mentioned Step 4 is agglomerated. Can be obtained.

[Electrophotographic toner]
The coalesced particles obtained in the step 4 are appropriately subjected to a solid-liquid separation step such as filtration, a washing step, and a drying step to obtain the electrophotographic toner of the present invention (sometimes simply referred to as a toner). be able to.
In the washing step, it is preferable to use an acid in order to remove metal ions on the surface of the toner in order to ensure sufficient charging characteristics and reliability as the toner. Further, it is preferable to completely remove the added nonionic surfactant by washing, and washing with an aqueous solution below the cloud point of the nonionic surfactant is preferred. The washing is preferably performed a plurality of times.
In the drying step, any method such as a vibration type fluidized drying method, a spray drying method, a freeze drying method, a flash jet method, or the like can be employed. The water content after drying of the toner is preferably adjusted to 1.5% by weight or less, more preferably 1.0% by weight or less, from the viewpoint of chargeability.

To the toner obtained as described above, an auxiliary agent such as a fluidizing agent may be added to the toner particle surface as an external additive. Examples of the external additive include silica fine particles whose surface is hydrophobized, titanium oxide fine particles, alumina fine particles, cerium oxide fine particles, and inorganic fine particles such as carbon black; polymer fine particles such as polycarbonate, polymethyl methacrylate, and silicone resin, and the like. Fine particles can be used.
The number average particle diameter of the external additive is preferably 4 to 200 nm, more preferably 8 to 30 nm. The number average particle diameter of the external additive is determined using a scanning electron microscope or a transmission electron microscope.

  When the external additive is added, the addition amount is 0.8 to 5 parts by weight with respect to 100 parts by weight of the toner before the processing with the external additive from the viewpoint of low-temperature fixability, glossiness and durability of the toner. 1 to 5 parts by weight is more preferable, and 1.5 to 3.5 parts by weight is still more preferable. However, when hydrophobic silica is used as the external additive, 0.8 to 3.5 parts by weight, preferably 1 to 3 parts by weight of hydrophobic silica is used with respect to 100 parts by weight of the toner before processing with the external additive. By using this, the desired effect can be obtained.

(Physical properties of electrophotographic toner)
The volume median particle size of the electrophotographic toner of the present invention is preferably from 1 to 10 μm, more preferably from 2 to 8 μm, and even more preferably from 3 to 7 μm, from the viewpoints of high image quality and productivity of the toner.
Further, the softening point of the toner is preferably 80 to 160 ° C., more preferably 80 to 150 ° C., and still more preferably 90 to 140 ° C. from the viewpoint of low-temperature fixability. Further, the glass transition temperature of the toner is preferably 45 to 80 ° C., more preferably 50 to 70 ° C. from the same viewpoint as described above.
The electrophotographic toner of the present invention can be used as a one-component developer or a two-component developer mixed with a carrier.

[Measurement of resin properties]
Measurement of softening point, endothermic maximum peak temperature, melting point, crystallinity index, glass transition temperature and acid value, number average molecular weight, volume median particle size (D ₅₀ ) of each particle obtained in each example The CV value was calculated as follows.
(Softening point of resin)
Using a flow tester (manufactured by Shimadzu Corporation, “CFT-500D”), a 1 g sample was heated at a rate of temperature increase of 6 ° C./min. Extruded from a 1 mm nozzle. The amount of plunger drop of the flow tester was plotted against the temperature, and the temperature at which half of the sample flowed out was taken as the softening point.
(Maximum peak temperature of the endotherm of resin, melting point, crystallinity index)
Using a differential scanning calorimeter (manufactured by TI Instruments Japan, "Q-100"), a sample cooled from room temperature (20 ° C) to 0 ° C at a rate of temperature decrease of 10 ° C / min for 1 minute. The measurement was performed while the temperature was raised to 150 ° C. at a temperature raising rate of 10 ° C./min. Among the observed endothermic peaks, the temperature of the peak on the highest temperature side was taken as the maximum peak temperature of the endotherm, and if the maximum peak temperature was within 20 ° C. from the softening point, the crystalline resin was taken as its melting point.
The crystallinity index was calculated by dividing the softening point by the maximum endothermic peak temperature.
(Resin acid value)
It measured based on the method of JISK0070. However, only the measurement solvent was changed from the mixed solvent of ethanol and ether specified in JIS K 0070 to a mixed solvent of acetone and toluene (acetone: toluene = 1: 1 (volume ratio)).

(Number average molecular weight of crystalline polyester)
The molecular weight distribution was measured by the gel permeation chromatography (GPC) method according to the following method to determine the number average molecular weight of the resin.
(1) Preparation of sample solution Polyester is dissolved in chloroform so that the concentration is 0.04 g / 10 ml. Next, this solution was filtered using a fluororesin filter having a mesh of 0.45 μm (manufactured by Advantech Co., Ltd., “DISMIC-25JP”) to remove insoluble components to obtain a sample solution.
(2) Molecular weight measurement Using the following apparatus, chloroform was allowed to flow at a flow rate of 1 ml / min, and the column was stabilized in a constant temperature bath at 40 ° C. Measurement was performed by injecting 100 μl of the sample solution. The molecular weight of the sample was calculated based on a calibration curve prepared in advance. For the calibration curve at this time, several types of monodisperse polystyrene prepared as standard samples were used.
Measuring device: HLC-8220 GPC (manufactured by Tosoh Corporation)
Analytical column: GMH _XL + G3000H _XL (manufactured by Tosoh Corporation)

(Glass transition temperature of amorphous resin)
Using a differential scanning calorimeter (manufactured by TA Instruments Japan, "Q-100"), 0.01 to 0.02 g of the sample was weighed into an aluminum pan, and the temperature was raised to 200 ° C. The sample cooled from the temperature to 0 ° C. at a rate of temperature decrease of 10 ° C./min is heated at a rate of temperature increase of 10 ° C./min, and the peak line extends from the baseline extension line below the maximum endothermic peak temperature and the peak rising portion. The temperature at the point of intersection with the tangent indicating the maximum slope until was taken as the glass transition temperature.
(Number average molecular weight of amorphous resin)
The measurement was performed in the same manner as the crystalline polyester except that the solvent was changed from chloroform to tetrahydrofuran (THF).

(Degree of neutralization of resin)
The degree of neutralization (%) when the resin is an anion can be determined by the following formula.
Degree of neutralization = {[weight of neutralizer (g) / equivalent of neutralizer] / [[acid value of resin (mgKOH / g) × resin weight (g)] / (56 × 1000)]} × 100
The degree of neutralization (%) when the resin is a cation can be determined by the following formula.
Degree of neutralization = {[weight of neutralizing agent (g) / equivalent of neutralizing agent] / [amine value of resin (mgHCl / g) × weight of resin (g) / (36.5 × 1000)]} × 100
The amine value is measured according to the acid value measurement method described above.

(Volume-median particle size (D ₅₀ ) of resin particles, colorant fine particles, release agent fine particles and charge control agent fine particles)
Laser diffraction-type particle size measuring instrument (Horiba Ltd., Ltd., "LA-920") using a distilled water was added to the measuring cell, a volume-median particle size in a concentration at which the absorbance is within a proper range (D ₅₀₎ Was measured.
The CV value was calculated according to the following formula. A lower CV value of the resin particles in the aqueous dispersion indicates that the particle diameters are uniform.
CV value (%) = (standard deviation of particle size distribution / volume median particle size (D ₅₀ )) × 100

In addition, as follows, the variation in the particle size with respect to the change in the degree of neutralization when the crystalline polyester obtained in each example was made into an aqueous dispersion was investigated.
(Investigation method for particle size variation)
In a 5 L container equipped with a stirrer, a reflux condenser, a dropping funnel, a thermometer, and a nitrogen introduction tube, 600 g of methyl ethyl ketone and 200 g of crystalline polyester were placed at 70 ° C. to dissolve the crystalline polyester.
A 5% aqueous potassium hydroxide solution was added to the resulting solution so as to achieve the neutralization degree shown in Table 1, followed by addition of 2500 g of ion-exchanged water, followed by depressurization at a stirring speed of 250 r / min. Then, methyl ethyl ketone was distilled off at 70 ° C. to 30 ppm or less. The solid concentration of the aqueous dispersion of the self-dispersing crystalline polyester was measured, and ion-exchanged water was added so that the solid concentration was 10% by weight to obtain a dispersion.
By measuring the volume median particle size (D ₅₀ ) of the crystalline polyester particles in the dispersion at each degree of neutralization and comparing the amount of variation in the volume median particle size, the degree of variation in the volume median particle size It was confirmed. It is preferable that the variation (variation) in the volume-median particle size of the crystalline polyester particles is smaller with respect to the variation in the degree of neutralization.

Examples 1 to 9 (Production of crystalline polyesters A-1 to A-9)
(Step 1-1)
In a 10 L four-necked flask equipped with a nitrogen introduction tube, a dehydration tube, a stirrer, and a thermocouple, at room temperature, a predetermined amount of raw material monomers other than trimellitic acid shown in Table 1, tin octylate 40 g, and gallic acid 2 g of acid monohydrate was added. The temperature was raised quickly to 180 ° C., and the reaction was carried out while raising the temperature from 180 ° C. to 210 ° C. over 10 hours, and the reaction was further carried out for 1 hour with the pressure reduced to 8 kPa and 210 ° C. Thereafter, trimellitic acid was added, the reaction was performed at 210 ° C. for 1 hour, stirring was stopped, and a crystalline polyester was obtained. The stirring speed during the reaction was 300 rpm.
(Step 1-2)
The polyester obtained in Step 1-1 was cooled under the conditions shown in Table 1. The maximum endothermic peak temperature (melting point) of the polyester obtained in Step 1-2 is shown.
As shown in Table 1, in Examples 1 and 3-9, after cooling in Step 1-2, the sample was allowed to stand at the same temperature for 5 days before performing Step 1-3 described later. In Example 2, Step 1 Step 1-3 described later was performed immediately after cooling at -2.
(Step 1-3)
The polyester obtained in the above step 1-2 was heated under the conditions shown in Table 1, and held for the time shown in Table 1 after the temperature rising to obtain crystalline polyesters A-1 to A-9. Table 1 shows the softening point, acid value, number average molecular weight and crystallinity index of the obtained crystalline polyester, and the volume-median particle size and CV value at each neutralization degree when an aqueous dispersion is used.

Comparative Example 1 (Production of crystalline polyester B-1)
In Example 1, operation was performed in the same manner except that Step 1-3 was not performed, and Crystalline Polyester B-1 was obtained. Table 1 shows the softening point, acid value, number average molecular weight and crystallinity index of the obtained crystalline polyester, and the volume-median particle size and CV value at each neutralization degree when an aqueous dispersion is used.

Comparative Example 2 (Production of crystalline polyester B-2)
In Example 2, the same operation was performed except that the cooling in Step 1-2 was changed to 80 ° C., to obtain crystalline polyester B-2. Table 1 shows the softening point, acid value, number average molecular weight and crystallinity index of the obtained crystalline polyester, and the volume-median particle size and CV value at each neutralization degree when an aqueous dispersion is used.

Example 10 (Production of crystalline polyester A-10)
(Step 1-1)
In a 10 L four-necked flask equipped with a nitrogen inlet tube, a dehydrating tube, a stirrer, and a thermocouple, at room temperature, a predetermined amount of raw material monomers shown in Table 1, tin octylate, 40 g of gallic acid monohydrate 2 g and 4 g of tertiary butyl catechol were added. The temperature was quickly raised to 130 ° C., the reaction was carried out while raising the temperature from 130 ° C. to 200 ° C. over 12 hours, and the reaction was further carried out at 200 ° C. until the acid value shown in Table 1 was reached by reducing the pressure to 20 kPa. Table 1 shows the measurement results of the endothermic maximum peak temperature of the obtained crystalline polyester.
(Steps 1-2 and 1-3)
The same operation as in Example 9 was carried out to obtain crystalline polyester A-10. Table 1 shows the softening point, acid value, number average molecular weight and crystallinity index of the obtained crystalline polyester, and the volume-median particle size and CV value at each neutralization degree when an aqueous dispersion is used.

From Table 1, the crystalline polyester obtained by the production method of the present invention has a small variation in the volume-median particle size with respect to the variation in the degree of neutralization when making an aqueous dispersion, and the control of the reaction is easier. I understand. In addition, the coefficient of variation (CV value) in the particle size distribution of the crystalline polyester particles is all 30% or less, which indicates that polyester particles having a narrow particle size distribution are formed.
Crystalline polyesters B-1 and B-2 have small particles obtained when the degree of neutralization is adjusted to 95%, but contain a large amount of resin that is dissolved in a solvent and is not formed into particles. It is considered that coarse particles are formed when the toner is formed.

Production Example 1 (Production of Amorphous Resin AA)
A 10 L four-necked flask equipped with a nitrogen inlet tube, a dehydrating tube, a stirrer, and a thermocouple is charged with a predetermined amount of raw material monomers other than trimellitic anhydride shown in Table 2 and 5 g of tertiary butyl catechol, The temperature was raised rapidly to 180 ° C., and the reaction was performed while raising the temperature from 180 ° C. to 210 ° C. over 10 hours. The reaction was further reduced to 8.3 kPa at 210 ° C. for 1 hour. Thereafter, trimellitic anhydride was added at 210 ° C. and reacted until reaching the softening point shown in Table 2 at 210 ° C. and 8 kPa to produce amorphous resin AA.

Production Example 2 (Production of amorphous resin AB)
In a 10 L four-necked flask equipped with a nitrogen inlet tube, a dehydrating tube, a stirrer and a thermocouple, a predetermined amount of raw material monomers other than trimellitic anhydride shown in Table 2, 40 g of tin octylate and 1 water of gallic acid 2 g of Japanese product was added and reacted at 230 ° C. for 8 hours, and then the pressure was reduced to 8.3 kPa and reacted at 230 ° C. for 1 hour. Furthermore, trimellitic anhydride was added at 210 ° C. and reacted until the softening point shown in Table 2 was reached to produce amorphous resin AB.

[Preparation of aqueous dispersion of crystalline polyester (step 2)]
In a 5 L container equipped with a stirrer, a reflux condenser, a dropping funnel, a thermometer and a nitrogen introduction tube, 600 g of methyl ethyl ketone and 200 g of crystalline polyester A-1 to A-10 or B-1 to B-2 were added at 70 ° C. And the crystalline polyester was dissolved.
A 5% aqueous potassium hydroxide solution was added to the resulting solution so that the degree of neutralization was 95%, and then 2500 g of ion-exchanged water was added, followed by a stirring speed of 250 r / min under reduced pressure. At 70 ° C., methyl ethyl ketone was distilled off to 30 ppm or less. The solid content concentration of the aqueous dispersion of the self-dispersing crystalline polyester was measured, and ion-exchanged water was added so that the solid content concentration was 10% by weight. To A-10 and dispersions B-1 to B-2) were obtained.
[Preparation of Aqueous Dispersion of Amorphous Resin (Step 2)]
In a 5 L vessel equipped with a stirrer, reflux condenser, dropping funnel, thermometer and nitrogen inlet tube, 600 g of methyl ethyl ketone and “Kao Akypo RLM-100” as an anionic surfactant (component: polyoxyethylene lauryl ether acetic acid) 2 g of Kao Corporation) was added, and 200 g of amorphous resin AA or AB was added at 50 ° C. to dissolve the amorphous resin.
To the obtained solution, potassium hydroxide was added so that the degree of neutralization was 90%, followed by addition of 2000 g of ion-exchanged water, and then at a temperature of 50 ° C. or lower under reduced pressure at a stirring speed of 250 r / min. Methyl ethyl ketone was distilled off to 30 ppm or less. The solid content concentration of the aqueous dispersion of the self-dispersing amorphous resin is measured, and ion-exchanged water is added so that the solid content concentration is 10% by weight. A dispersion of Resin AB was obtained.

(Preparation of colorant dispersion)
50 g of copper phthalocyanine (manufactured by Dainichi Seika Kogyo Co., Ltd., model number: ECB-301), 5 g of a nonionic surfactant (“Emulgen (registered trademark) 150”, manufactured by Kao Corporation) and 200 g of ion-exchanged water are mixed. Phthalocyanine was dissolved and dispersed for 10 minutes using a homogenizer to obtain a colorant dispersion containing colorant fine particles. The volume median particle size of the colorant fine particles was 120 nm.
(Preparation of release agent dispersion)
Paraffin wax (“HNP9”, manufactured by Nippon Seiwa Co., Ltd., melting point: 85 ° C.) 50 g, cationic surfactant (“Sanisol (registered trademark) B50”, manufactured by Kao Corp.) 5 g and ion-exchanged water 200 g were added at 95 ° C. Then, the homogenizer was used to disperse the paraffin wax, followed by dispersion treatment with a pressure discharge homogenizer to obtain a release agent dispersion containing release agent fine particles. The volume median particle size of the release agent fine particles was 550 nm.
(Preparation of charge control agent dispersion)
50 g of charge control agent (“Bontron E-84”, manufactured by Orient Chemical Co., Ltd.), 5 g of nonionic surfactant (“Emulgen (registered trademark) 150”, manufactured by Kao Corporation) and 200 g of ion-exchanged water are mixed. Glass beads were used and dispersed for 10 minutes using a sand grinder to obtain a charge control agent dispersion liquid containing charge control agent fine particles. The volume median particle size of the charge control agent fine particles was 500 nm.

Examples 11 to 20 and Comparative Examples 3 to 5 (Toner Production Method)
(Process 3)
300 g of resin dispersion, 8 g of colorant dispersion, 6 g of release agent dispersion, 6 g of charge control agent dispersion in which the dispersions are mixed so that the content of the crystalline polyester and the amorphous resin are in the ratio shown in Table 3. 2 g of liquid and 52 g of deionized water were placed in a 2 L container.
Next, 146 g of a 6.2 wt% aqueous ammonium sulfate solution was added dropwise at room temperature with stirring at 100 r / min with a Kai-type stirrer over 30 minutes. Then, it heated up, stirring, when it became 50 degreeC, it fixed to 50 degreeC and hold | maintained for 3 hours. After forming aggregated particles by this, a dilute solution obtained by diluting 4.2 g of a polyoxyethylene dodecyl ether sodium sulfate aqueous solution (solid content 28 wt%) with 37 g of deionized water was added as an aggregation terminator.
(Process 4)
Next, the temperature was raised to 80 ° C. at 0.16 ° C./min. After the temperature reached 80 ° C., the temperature was maintained at 80 ° C. for 1 hour, and then the heating was terminated. As a result, coalesced particles were formed, and then gradually cooled to room temperature, and toner particles were obtained through a suction filtration process, a washing process, and a drying process.
(surface treatment)
Further, 1.0 part by weight of hydrophobic silica “NAX-50” (number average particle size 40 nm, manufactured by Nippon Aerosil Co., Ltd.) and 0.6 part by weight of hydrophobic silica “R972” with respect to 100 parts by weight of toner base particles. (Nippon Aerosil Co., Ltd., number average particle size 16 nm) and 0.5 parts by weight of titanium oxide “JMT-150IB” (Taika Co., Ltd., average particle size 15 nm) were added to a 10 L Henschel mixer (Mitsui Mining Co., Ltd.). ) Were equipped with ST (upper blade) -A0 (lower blade) type stirring blades, and stirred at 3000 rpm for 2 minutes to perform external addition processing, whereby toners T-1 to T-13 were obtained.

The obtained toner was evaluated for low-temperature fixability, glossiness, and durability at room temperature and high humidity as follows. The results are shown in Table 3.
(Fixability)
A toner was mounted on a copying machine “AR-505” (manufactured by Sharp Corporation), and an image was printed without fixing (printing area: 2 cm × 12 cm, adhesion amount: 0.5 mg / cm ² ). The fixing machine of the copying machine was fixed on paper at 400 mm / sec while increasing the fixing temperature from 90.degree. C. to 240.degree. For the fixing paper, “CopyBond SF-70NA” (manufactured by Sharp Corporation, 75 g / m ² ) was used.
“UNICEF cellophane” (manufactured by Mitsubishi Pencil Co., Ltd., width: 18 mm, JIS Z-1522) was attached to the fixed image, passed through a fixing roller set at 30 ° C., and then the tape was peeled off. The optical reflection density before and after the tape was peeled was measured using a reflection densitometer “RD-915” (manufactured by Gretag Macbeth), and the ratio between the two (after peeling / before sticking) first exceeded 90%. The fixing roller temperature was set to the minimum fixing temperature, and the low-temperature fixing property was evaluated according to the following evaluation criteria. The lower the minimum fixing temperature, the better the low temperature fixing property. In addition, the crystalline polyester is finely dispersed and the smaller the coarse particles, the better the low-temperature fixability.
A: The minimum fixing temperature is less than 120 ° C.
B: The minimum fixing temperature is 120 or more and less than 130 ° C.
C: The minimum fixing temperature is 130 or more and less than 145 ° C.
D: The minimum fixing temperature is 145 ° C. or higher.

(Glossy)
A toner was mounted on a copying machine “AR-505” (manufactured by Sharp Corporation), and an image was printed without fixing (printing area: 2 cm × 12 cm, adhesion amount: 0.5 mg / cm ² ). J paper (manufactured by Fuji Xerox) was used as the printing medium. The fixing machine of the copying machine was fixed on paper at 160 ° C. and 400 mm / sec offline.
A white cardboard is laid under the image, and the glossiness of the printed image is measured at an incident angle of 60 degrees using a gloss meter (“IG-330” manufactured by Horiba, Ltd.). The gloss was evaluated according to the criteria. The higher the obtained value, the higher the glossiness of the printed image and the better the glossiness. When there are coarse particles, the gloss tends to decrease.
A: 20 or more B: 15 or more and less than 20 C: 10 or more and less than 15 D: 10 or less

(Durability under normal temperature and high humidity)
After mounting toner on a non-magnetic one-component developing device “MicroLine 9300PS” (manufactured by Oki Data Co., Ltd.), printing 20 images at a printing rate of 5% in an environment of 25 ° C. and a relative humidity of 90%, the optical reflection density Was measured using a reflection densitometer “RD-915” (manufactured by Gretag Macbeth).
Furthermore, after printing 1000 sheets, the optical reflection density was measured again using a reflection densitometer “RD-915” (manufactured by Gretag Macbeth). The difference between the two image densities was calculated, and the durability was evaluated according to the following evaluation criteria. It shows that it is excellent in durability, so that an image density difference is small. Note that if there is a non-crystallized portion, the toner will come out on the toner surface and absorb moisture, so that the durability tends to deteriorate.
A: Image density difference is less than 0.15 B: Image density difference is 0.15 or more and less than 0.3 C: Image density difference is 0.3 or more and less than 0.45 D: Image density difference is 0.45 or more

From Table 3, toners T-1 to T-10 obtained by the production method of the present invention are toners containing crystalline polyester obtained without performing Step 1-2 or 1-3 in the production method of the present invention. It has higher low-temperature fixability than T-11 and T-12, and is also excellent in glossiness and durability. Further, the toner T-13 not containing the crystalline polyester of the present invention also has lower low-temperature fixability, glossiness and durability than the toners T-1 to T-10.
In addition, from Examples 11 and 12 in Table 3, the low temperature fixing property, glossiness and durability were further improved by providing the time required for the transition from Step 1-2 to Step 1-3 for 5 days. From Example 11 and Examples 13-15, by extending the time required to reach the predetermined cooling temperature (50 ° C.) in Step 1-2 from 0.5 hours to 2 hours, 4 hours or 8 hours, Fixability, gloss and durability were further improved. From Example 11 and Examples 16 and 17, the low temperature fixability, glossiness and durability were further improved by extending the heat treatment time in Step 1-3 from 0.5 hours to 2 hours or 10 hours. .

  The toner containing the crystalline polyester and the binder resin obtained by the present invention is excellent in low-temperature fixability, glossiness and durability at room temperature and high humidity, so that it can be electrophotographic, electrostatic recording, electrostatic printing, etc. It can be suitably used as an electrophotographic toner used in the above.

Claims (7)

A method for producing a binder resin for toner, comprising the following steps 1 to 4.
Step 1: Polycondensation of an alcohol component containing an aliphatic diol having 2 to 10 carbon atoms and a carboxylic acid component containing one or more selected from an aromatic dicarboxylic acid compound and an aliphatic dicarboxylic acid compound having 2 to 6 carbon atoms After being subjected to the reaction, after cooling to 50 ° C. or lower, the temperature is higher than 50 ° C., and “maximum endothermic peak temperature (° C.)-60 ° C.” to “maximum endothermic peak temperature (° C.)-5 ° C. To obtain a crystalline polyester.
Step 2: A step of obtaining an aqueous dispersion containing the crystalline polyester obtained in Step 1.
Step 3: A step of obtaining an aqueous dispersion of aggregated particles by mixing the aqueous dispersion containing the crystalline polyester obtained in Step 2 with an aqueous dispersion containing an amorphous resin and then subjecting to an aggregation step.
Step 4: A step of obtaining an aqueous dispersion of coalesced particles by subjecting the aqueous dispersion of aggregated particles obtained in Step 3 to an coalescence step.   An electrophotographic toner containing the binder resin for toner obtained by the production method according to claim 1. A method for producing a crystalline polyester for toner, comprising the following steps 1-1 to 1-3.
Step 1-1: An alcohol component containing an aliphatic diol having 2 to 10 carbon atoms, and a carboxylic acid component containing one or more selected from an aromatic dicarboxylic acid compound and an aliphatic dicarboxylic acid compound having 2 to 6 carbon atoms. A step of subjecting it to a condensation polymerization reaction.
Process 1-2: The process of cooling the polyester obtained at the process 1-1 until it becomes 50 degrees C or less.
Step 1-3: The temperature of the polyester cooled in Step 1-2 is higher than 50 ° C., and “endothermic maximum peak temperature (° C.)-60 ° C.” to “endothermic maximum peak temperature (° C.)-5 ° C. The process of heat-treating.   The method for producing a crystalline polyester for toner according to claim 3, wherein in step 1-2, the cooling time from the temperature at the end of the condensation polymerization reaction in step 1-1 to 50 ° C is 1 to 24 hours.   The method for producing a crystalline polyester for toner according to claim 3 or 4, wherein the heat treatment time in Step 1-3 is 0.5 to 48 hours.   The method for producing a crystalline polyester for toner according to any one of claims 3 to 5, wherein Step 1-3 is carried out after one or more days have passed after Step 1-2.   A crystalline polyester for toner obtained by the production method according to claim 3.