JP5859760B2 - Toner for electrophotography - Google Patents

Description

  The present invention relates to an electrophotographic toner and a method for producing the same.

In the field of electrophotographic toner, with development of an electrophotographic system, development of a toner corresponding to high image quality and high speed is required.
In order to achieve both high image quality and high speed, it is necessary to satisfy a plurality of conflicting performances. For this reason, development of a core-shell type toner that forms a layer structure inside the toner has been performed.

For example, Patent Document 1 discloses a hot-melt core material containing a thermoplastic resin and a colorant for the purpose of improving offset resistance, low-temperature fixability, charging stability under high temperature and high humidity, and image quality, and its Constructed to cover the surface of the core material, the main component is composed of the outer shell, which is a resin having a molecular structure in which the molecular chain generated by condensation polymerization and the molecular chain generated by addition polymerization are chemically bonded A capsule toner for heat pressure fixing is disclosed.
Patent Document 2 discloses that a toner inner layer containing a radical polymer resin, a colorant, and a release agent, and an outer edge thereof are unsaturated in the main chain for the purpose of improving fixing strength, offset resistance, and heat storage stability. There is disclosed a toner formed by agglomerating resin particles in a liquid medium, having a toner outer layer containing a grafted polyester resin formed by graft polymerization of a radically polymerizable monomer to a polyester having a bond.
Patent Document 3 includes a composite resin in which a styrene resin and a polyester resin are bonded for the purpose of improving the fixing latitude, heat storage property, and charging property, and includes a crystalline polyester resin, an amorphous polyester resin, and A toner for electrostatic charge image development having a core-shell structure in which a shell containing a copolymer resin of polystyrene and (meth) acryl is provided on the surface of core particles containing a colorant is disclosed.
Further, Patent Document 4 obtains an electrostatic charge developing toner containing at least a crystalline polyester resin and a colorant and having a specific dielectric loss ratio for the purpose of improving low-temperature fixability, high density image, and fog suppression. As a method for this, a resin particle dispersion in which binder resin particles containing a crystalline polyester resin are dispersed and a colorant dispersion in which a colorant is dispersed are mixed, and an aggregating agent is added thereto to form aggregated particles. A method for producing a toner is disclosed, which includes an aggregated particle forming step and a fusion / union step in which the aggregated particle is heated and fused and united while adding an acid and a surfactant.

JP-A-8-171231 JP 2006-215312 A JP 2007-93809 A JP 2009-75342 A

By using crystalline polyester and a release agent in the toner, the fixing temperature of the obtained toner can be lowered due to its melting characteristics. Thereby, the power consumption of the printing machine can be reduced, and a toner suitable for high-speed printing can be obtained. However, a toner containing crystalline polyester and a release agent also has problems such as low heat storage stability, which is stability at high temperature storage, and low chargeability.
An object of the present invention is to provide an electrophotographic toner that has both good low-temperature fixability and chargeability under high temperature and high humidity, and excellent heat-resistant storage stability, and a method for producing the same.

  The inventors of the present invention have considered that the factors affecting the fixing temperature, chargeability, and heat-resistant storage stability are the position and state of the resin and release agent constituting the toner. As a result, the particle structure of the toner has a core-shell structure in which a core containing a specific crystalline polyester and a release agent is included in a shell made of a specific graft polymer composed of a polyester resin segment and an addition polymerization resin segment. As a result, it was found that an electrophotographic toner having both good low-temperature fixability and chargeability under high temperature and high humidity and excellent heat-resistant storage stability can be obtained.

That is, the present invention provides the following [1] and [2].
[1] Crystalline polyester (a) obtained by polycondensation of an α, ω-alkanediol having 4 to 12 carbon atoms and an aliphatic dicarboxylic acid having 8 to 12 carbon atoms and a release agent having a melting point of 60 to 90 ° C. And a core-shell type electrophotographic toner comprising a core made of a graft polymer composed of a side chain segment (A1) made of a polyester resin and a main chain segment (A2) made of an addition polymerization resin. The toner for electrophotography, wherein the weight ratio [(A1) / (A2)] of the side chain segment (A1) to the main chain segment (A2) is 95/5 to 55/45.
[2] The method for producing a core-shell type electrophotographic toner according to [1], comprising the following steps (1) to (3):
Step (1): Resin particles (A) containing crystalline polyester (a) obtained by polycondensation of α, ω-alkanediol having 4 to 12 carbon atoms and aliphatic dicarboxylic acid having 8 to 12 carbon atoms And a step of agglomerating release agent particles having a melting point of 60 to 90 ° C. to obtain aggregated particles (1) Step (2): The aggregated particles (1) obtained in Step (1) are made of a polyester resin. Step of adding aggregated particles (2) by adding resin particles (B) containing a graft polymer composed of side chain segments (A1) and main chain segments (A2) made of addition polymerization resin Step (3) : A step of obtaining core-shell particles by maintaining the temperature of the system containing the agglomerated particles (2) at a temperature of 10 ° C. lower than the glass transition point of the graft polymer and fusing them.

  According to the present invention, it is possible to provide an electrophotographic toner that has both good low-temperature fixability and chargeability under high temperature and high humidity, and excellent heat resistant storage stability, and a method for producing the same.

  The electrophotographic toner of the present invention comprises a crystalline polyester (a) obtained by condensation polymerization of an α, ω-alkanediol having 4 to 12 carbon atoms and an aliphatic dicarboxylic acid having 8 to 12 carbon atoms, and a melting point of 60 to 60. A core containing a release agent at 90 ° C., a shell made of a graft polymer composed of a side chain segment (A1) made of a polyester resin and a main chain segment (A2) made of an addition polymerization resin, and a side chain The core-shell type toner has a weight ratio [(A1) / (A2)] of the segment (A1) to the main chain segment (A2) of 95/5 to 55/45.

The reason why the electrophotographic toner of the present invention has both good low-temperature fixability and high-temperature and high-humidity chargeability and excellent heat-resistant storage stability is not clear, but can be considered as follows.
The core of the toner of the present invention contains a crystalline polyester obtained from an alkanediol having a relatively long carbon number and an aliphatic dicarboxylic acid, and a release agent. Since these can be quickly melted and fixed at a low temperature, the toner of the present invention is considered to have excellent low-temperature fixability. On the other hand, since these are easily melted at low temperatures, these crystalline polyesters and mold release agents have a disadvantage in chargeability and heat-resistant storage stability under high temperature and high humidity. In the present invention, these core portions are covered with a shell portion made of a graft polymer composed of a side chain segment (A1) made of a polyester resin and a main chain segment (A2) made of an addition polymerization resin.
The graft polymer constituting this shell part has a segment made of an addition polymerization resin having a low affinity with crystalline polyester in the main chain part, so it is difficult to mix with the core part and forms a clear layer structure. It is thought that the exposure to the surface of the crystalline polyester and the mold release agent that are easily melted is suppressed. On the other hand, since this graft polymer has more segments made of polyester resin having high affinity with crystalline polyester in the side chain portion than segments made of addition polymerization resin, the side chain enters the core portion, and the core and shell It is considered that the core shell structure is strengthened by preventing separation and peeling.
Thus, the electrophotographic toner of the present invention is considered to be excellent in all of low-temperature fixability, chargeability under high temperature and high humidity, and heat-resistant storage stability.
Hereafter, each component etc. which are used for this invention are demonstrated.

[Crystalline Polyester (a)]
The crystalline polyester (a) in the present invention is a crystalline polyester obtained by condensation polymerization of an α, ω-alkanediol having 4 to 12 carbon atoms and an aliphatic dicarboxylic acid having 8 to 12 carbon atoms.
In the present invention, the crystallinity is defined as a ratio of a softening point to a maximum endothermic peak temperature by a differential scanning calorimeter (DSC), (softening point (° C)) / (maximum endothermic peak temperature (° C)). The crystallinity index is 0.6 to 1.4.
From the viewpoint of low-temperature fixability of the toner, the crystalline polyester (a) preferably has a crystallinity index of 0.8 to 1.3, more preferably 0.9 to 1.2, and 0.9. More preferred are those of -1.1.
The crystalline polyester (a) preferably has an acid group at the molecular end from the viewpoint of emulsification during production. Examples of the acid group include a carboxyl group, a sulfonic acid group, a phosphonic acid group, and a sulfinic acid. Among these, a carboxyl group is preferable from the viewpoint of achieving both the dispersibility of the resin and the storage stability of the obtained toner.

The melting point of the crystalline polyester (a) is preferably from 50 to 150 ° C., more preferably from 60 to 90 ° C., and still more preferably from 70 to 80 ° C., from the viewpoint of low-temperature fixability and storage stability of the toner.
From the same viewpoint, the softening point of the crystalline polyester (a) is preferably 50 to 140 ° C, more preferably 60 to 90 ° C, and still more preferably 70 to 80 ° C.
The acid value of the crystalline polyester (a) is preferably 5 to 40 mgKOH / g, more preferably 10 to 25 mgKOH / g, and more preferably 15 to 20 mgKOH / g from the viewpoint of improving the dispersibility of the resin particle dispersion (A) described later. Is more preferable.
The number average molecular weight of the crystalline polyester (a) is preferably 1,500 to 50,000, more preferably 2,000 to 10,000, and more preferably 3,000 to 5,000, from the viewpoint of low-temperature fixability and storage stability of the toner. 5,000 is more preferable.
In addition, crystalline polyester (a) can be used individually or in combination of 2 or more types.
In the present invention, the melting point, softening point and number average molecular weight of the crystalline polyester (a) are values determined by the methods described in the examples. When using 2 or more types together, it is the value which calculated | required the mixture by the method as described in an Example.

The crystalline polyester (a) in the present invention preferably contains an α, ω-alkanediol having 4 to 12 carbon atoms as an alcohol component and an aliphatic dicarboxylic acid having 8 to 12 carbon atoms as an acid component, preferably in the presence of a catalyst. It is preferable to manufacture by carrying out the condensation polymerization reaction at 180 to 250 ° C. below.
The α, ω-alkanediol having 4 to 12 carbon atoms used as an alcohol component increases affinity with the shell portion and the release agent of the obtained toner, strengthens the core-shell structure, and melts at a low temperature during fixing. From the viewpoint of improving the low-temperature fixability, α, ω-alkanediol having 6 to 9 carbon atoms is preferable, and from the viewpoint of storage stability and chargeability, α, ω-alkanediol having 8 to 9 carbon atoms is more preferable. . Specific examples of the α, ω-alkanediol having 4 to 12 carbon atoms include 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8- Examples include octanediol, 1,9-nonanediol, 1,10-decanediol, and 1,12-dodecanediol. Among them, 1,6-hexane is used from the viewpoint of low-temperature fixability, storage stability, and chargeability of the toner. Diol, 1,9-nonanediol, 1,10-decanediol and 1,12 dodecanediol are preferable, 1,6-hexanediol and 1,9-nonanediol are more preferable, from the viewpoint of storage stability and chargeability. 1,9-nonanediol is more preferable.
An alcohol component other than the α, ω-alkanediol having 4 to 12 carbon atoms can be used as long as the effects of the present invention are not impaired.
The α, ω-alkanediol having 4 to 12 carbon atoms can be used alone or in combination of two or more.

The aliphatic dicarboxylic acid having 8 to 12 carbon atoms used as an acid component increases the affinity with the shell portion and the release agent of the obtained toner, strengthens the core-shell structure, and melts at a low temperature during fixing. From the viewpoint of enhancing the low-temperature fixability, an aliphatic dicarboxylic acid having 10 to 12 carbon atoms is preferable, and from the viewpoint of storage stability and chargeability, an aliphatic dicarboxylic acid having 10 to 11 carbon atoms is more preferable. Specific examples of the aliphatic dicarboxylic acid having 8 to 12 carbon atoms include suberic acid, azelaic acid, sebacic acid, 1,11-undecanedioic acid, and 1,12-dodecanedioic acid. Sebacic acid and 1,12-dodecanedioic acid are preferable from the viewpoints of stability, storage stability and chargeability, and sebacic acid is more preferable from the viewpoints of storage stability and chargeability.
In the present invention, the aliphatic dicarboxylic acid having 8 to 12 carbon atoms includes anhydrides of these acids and alkyl esters having 1 to 3 carbon atoms.
An acid component other than the aliphatic dicarboxylic acid having 8 to 12 carbon atoms can be used as long as the effects of the present invention are not impaired.
The aliphatic dicarboxylic acid having 8 to 12 carbon atoms can be used alone or in combination of two or more.

As the catalyst, from the viewpoint of the efficiency of the condensation polymerization reaction, a tin compound, a titanium compound, and the like are preferable, a tin compound is more preferable, and di (2-ethylhexanoic acid) tin, dibutyltin oxide, and the like can be given. Ethylhexanoic acid) tin is preferred.
Examples of the titanium compound include titanium diisopropylate bistriethanolamate.
Although there is no restriction | limiting in the usage-amount of a catalyst, 0.01-1 weight part is preferable with respect to 100 weight part of total amounts of an acid component and an alcohol component, and 0.1-0.6 weight part is more preferable.
The polycondensation reaction is preferably performed by adding an acid component and an alcohol component to a reaction vessel and maintaining at 140 to 200 ° C. for 5 to 15 hours, and then adding a catalyst and maintaining at 140 to 200 ° C. for 1 to 5 hours. Then, the reaction is allowed to proceed, and the method of obtaining the crystalline polyester by reducing the pressure to 5.0 to 20 kPa and maintaining it for 1 to 10 hours is preferable.

[Amorphous polyester (b)]
The toner for electrophotography of the present invention is a core-shell type containing a crystalline polyester (a) and a releasing agent having a melting point of 60 to 90 ° C. in the core, but the storage stability is maintained while maintaining the low-temperature fixability of the toner. From the viewpoint of improving chargeability and preventing hot offset, the core preferably further contains an amorphous polyester (b).
In the present invention, the term “amorphous” means that the above-mentioned crystallinity index exceeds 1.4 or is less than 0.6.
The amorphous polyester (b) preferably has a crystallinity index of less than 0.6 or more than 1.4 and 4 or less, more preferably less than 0.6, from the viewpoint of low-temperature fixability of the toner. It is 1.5 or more and 4 or less, More preferably, it is less than 0.6 or 1.5 or more and 3 or less, More preferably, it is less than 0.6 or 1.5 or more and 2 or less. The crystallinity index can be appropriately determined depending on the type and ratio of the raw material monomers and the production conditions.
As the amorphous polyester (b), an amorphous polyester (b) having a carboxy group at the molecular end is preferable.
The amorphous polyester (b) can be produced by subjecting an alcohol component and an acid component to a polycondensation reaction in the same manner as the crystalline polyester (a), and preferred catalysts and reaction conditions are also the same. .

Examples of the alcohol component include aromatic diols, aliphatic diols, and trihydric or higher polyhydric alcohols. The affinity with the polyester resin in the shell portion is increased, the storage stability of the toner is kept good, and the chargeability of the toner is increased. From the viewpoint of improvement, an aromatic diol is preferable.
As the aromatic diol, from the above viewpoint, a diol having a 2,2-bis (4-hydroxyphenyl) propane structure is preferable, and an alkylene oxide adduct of 2,2-bis (4-hydroxyphenyl) propane is more preferable. .

Specifically, the alkylene oxide adduct of 2,2-bis (4-hydroxyphenyl) propane is preferably a compound represented by the following general formula (I).

In the general formula (I), R ^a O and R ^b O are both alkyleneoxy groups, preferably each independently an alkyleneoxy group having 1 to 4 carbon atoms, more preferably an ethyleneoxy group or a propyleneoxy group. It is.
x and y correspond to the added mole number of alkylene oxide, and are positive numbers. Furthermore, from the viewpoint of reactivity with the carboxylic acid component, the average value of the sum of x and y is preferably 2 to 7, more preferably 2 to 5, and still more preferably 2 to 3.
Further, x R ^a O or y R ^b O may be the same or different from each other, but are preferably the same from the viewpoint of obtaining homogeneous emulsified particles, and are propyleneoxy groups. It is more preferable.
From the viewpoint of increasing the affinity with the shell portion, forming a core-shell structure more uniformly, and thus improving the chargeability of the toner, the content of the propyleneoxy group is preferably 50 to 100 mol in the alkyleneoxy group. %, More preferably 80 to 100 mol%, still more preferably substantially 100 mol%.
The alkylene oxide adduct of 2,2-bis (4-hydroxyphenyl) propane may be used alone or in combination of two or more, and a propylene oxide adduct of 2,2-bis (4-hydroxyphenyl) propane It is preferable to use a mixture of 2,2-bis (4-hydroxyphenyl) propane and an ethylene oxide adduct. The mixing molar ratio of the propylene oxide adduct of 2,2-bis (4-hydroxyphenyl) propane and the ethylene oxide adduct of 2,2-bis (4-hydroxyphenyl) propane is 50/50 to 99/1. Preferably, 60 / 40-80 / 20 is more preferable.

  From the viewpoint of chargeability and durability of the toner, the alkylene oxide adduct of 2,2-bis (4-hydroxyphenyl) propane is preferably 50 mol% or more, more preferably 70 mol% or more in the alcohol component. Preferably it is 80 mol% or more, More preferably, it contains substantially 100 mol%. In the present invention, the alkylene oxide adduct means the entire structure in which an alkyleneoxy group is added to 2,2-bis (4-hydroxyphenyl) propane.

Examples of the aliphatic diol include ethylene glycol, propylene glycol (1,2-propanediol), and hydrogenated bisphenol A.
Examples of the trihydric or higher polyhydric alcohol include glycerin, pentaerythritol, trimethylolpropane, and sorbitol. You may use the said alcohol component individually or in combination of 2 or more types.

  Examples of the acid component include aromatic dicarboxylic acid, aliphatic dicarboxylic acid, alicyclic dicarboxylic acid, and trivalent or higher polyvalent carboxylic acid. The affinity with the polyester resin in the shell portion is increased, and the storage stability of the toner is increased. From the viewpoint of keeping good and improving the chargeability of the toner, aromatic dicarboxylic acids and aliphatic dicarboxylic acids are preferred, aromatic dicarboxylic acids are more preferred, and aromatic dicarboxylic acids and aliphatic dicarboxylic acids are more preferably used in combination. .

Examples of the aromatic dicarboxylic acid include terephthalic acid, isophthalic acid, and phthalic acid, and terephthalic acid is preferable from the viewpoint of chargeability of the toner.
Examples of the aliphatic dicarboxylic acid include succinic acid, fumaric acid, maleic acid, adipic acid, and succinic acid having an alkyl group and / or an alkenyl group. From the viewpoint, a succinic acid having an alkyl group and / or an alkenyl group is preferable, and an alkyl succinic acid having a branched alkyl group having 9 to 14 carbon atoms and / or an alkenyl succinic acid having an alkenyl group having 9 to 14 carbon atoms. It is preferable. From the viewpoint of low-temperature fixability, an alkyl succinic acid having a branched alkyl group having 9 to 14 carbon atoms and / or an alkenyl succinic acid having an alkenyl group having 9 to 14 carbon atoms is an acid component of the amorphous polyester (b). It is preferable to contain 20-50 mol% in.
Examples of the alicyclic dicarboxylic acid include cyclohexane dicarboxylic acid, decalin dicarboxylic acid, and tetrahydrophthalic acid.
Examples of the trivalent or higher polyvalent carboxylic acid include trimellitic acid and pyromellitic acid, and trimellitic acid is preferable from the viewpoint of chargeability.
The said carboxylic acid component may be individual or 2 or more types may be contained. The carboxylic acid includes anhydrides of these acids and alkyl esters having 1 to 3 carbon atoms.

The softening point of the amorphous polyester (b) is preferably from 70 to 165 ° C, more preferably from 100 to 130 ° C, and even more preferably from 110 to 120 ° C, from the viewpoints of toner durability, low-temperature fixability and storage stability. .
The glass transition point of the amorphous polyester (b) is preferably 50 to 70 ° C., more preferably 50 to 65 ° C., and further preferably 55 to 60 ° C. from the viewpoints of toner durability, low-temperature fixability and storage stability. preferable.
The acid value of the amorphous polyester (b) is preferably 6 to 35 mgKOH / g, more preferably 10 to 25 mgKOH / g, and still more preferably 15 to 20 mgKOH / g, from the viewpoint of emulsification in an aqueous medium of the resin.
The number average molecular weight of the amorphous polyester (b) is preferably 1,000 to 50,000, more preferably 2,000 to 5,000, from the viewpoints of toner durability, low-temperature fixability and storage stability. 800 to 4,000 is more preferable.
In addition, these values in the case of using 2 or more types of amorphous polyester (b) in mixture are the values obtained by measuring the mixture according to the measurement method described in the examples.

  The total amount of the crystalline polyester (a) and the amorphous polyester (b) in the core is preferably 50 to 100% by weight in the resin constituting the core, more preferably 80 to 80% from the viewpoint of improving the low-temperature fixability of the toner. 100% by weight, more preferably 90-100% by weight. The weight ratio ((a) / (b)) between the crystalline polyester (a) and the amorphous polyester (b) in the core improves the low-temperature fixability, storage stability, and chargeability of the toner and reduces hot offset. From the viewpoint of prevention, it is preferably 5/95 to 50/50, more preferably 5/95 to 40/60, more preferably 10/90 to 30/70, and further preferably 13/87 to 25/75, 15/85 to 20/80 is even more preferable.

[Release agent]
The mold release agent used in the present invention is a mold release agent having a melting point of 60 to 90 ° C. Examples of the releasing agent having a melting point of 60 to 90 ° C. include low molecular weight polyolefins, silicones, fatty acid amides, plant waxes, animal waxes, and mineral / petroleum waxes.
The melting point of the release agent is 60 to 90 ° C., preferably 70 to 85 ° C., more preferably 75 to 83 ° C., from the viewpoint of low-temperature fixability, storage stability, and chargeability of the toner.
The release agents can be used alone or in combination of two or more, but it is preferable to use two types having different melting points of 5 ° C. or more, and the melting points of all the release agents are 60 to 90 ° C. preferable. When the two types are used in combination, the melting point of the release agent having a high melting point is preferably 75 to 90 ° C, more preferably 80 to 86 ° C, and the melting point of the release agent having a low melting point is preferably 60 to 80 ° C. Preferably it is 65-77 degreeC, More preferably, it is 70-76 degreeC.
In the present invention, the melting point of the release agent is determined by the method described in the examples.

As the release agent, mineral / petroleum wax, plant wax, animal wax, synthetic wax and the like can be used. Among these, from the viewpoint of improving the low-temperature fixability of the toner, mineral / petroleum waxes and vegetable waxes are preferable, and mineral / petroleum waxes are more preferable.
Examples of the mineral / petroleum wax include paraffin wax and montan wax. Among them, paraffin wax is preferable from the viewpoint of improving the low-temperature fixability of the toner and maintaining good storage stability.
Examples of plant-based waxes include carnauba wax, rice wax, and candelilla wax. Carnauba wax is preferred from the viewpoint of increasing affinity with a polyester resin and improving toner chargeability.
Specific examples of carnauba wax include “carnauba wax 1” (melting point 83 ° C.), “carnauba wax 2” (melting point 83 ° C.), “special carnauba wax 1” (melting point 83 ° C.), “ Special Carnauba Wax No. 2 ”(melting point: 83 ° C.) and the like (both are trade names, manufactured by Hiroyuki Kato).
Animal waxes include beeswax and the like. Examples of the synthetic wax include polyolefin wax, silicone wax, fatty acid amides, Fischer-Tropsch wax and the like. Specific examples of the polyolefin wax include low molecular weight polyethylene, low molecular weight polypropylene, and polybutene. Specific examples of the silicone wax include silicones having a softening point and solid at room temperature. Specific examples of fatty acid amides include oleic acid amide and stearic acid amide.
The structure of the release agent is preferably a hydrocarbon wax from the viewpoint of low-temperature fixability, and more preferably a hydrocarbon wax and an ester wax are used in combination.
Among the hydrocarbon waxes, paraffin wax is preferable, and among the ester waxes, carnauba wax is preferable.
The amount of the release agent used is 1 to 20 parts by weight with respect to 100 parts by weight of all the resins in the toner from the viewpoint of improving the low-temperature fixability by improving the releasability of the toner and from the viewpoint of chargeability. Preferably, 2 to 15 parts by weight is more preferable, and 5 to 13 parts by weight is still more preferable.

[Graft polymer composed of side chain segment (A1) made of polyester resin and main chain segment (A2) made of addition polymerization resin]
The graft polymer used in the present invention comprises a side chain segment (A1) composed of a polyester resin (hereinafter also simply referred to as “segment (A1)”) and a main chain segment (A2) composed of an addition polymerization resin (hereinafter simply referred to as “ Segment (A2) ”).

The softening point of the graft polymer is preferably from 80 to 150 ° C, more preferably from 100 to 140 ° C, and even more preferably from 110 to 135 ° C, from the viewpoint of heat resistant storage stability of the toner.
The acid value of the graft polymer is preferably 5 to 40 mgKOH / g, more preferably 10 to 30 mgKOH / g, from the viewpoints of dispersion stability of the resin particle dispersion (B), obtaining uniform toner particles, and toner chargeability. 20 to 25 mgKOH / g is more preferable.
The number average molecular weight of the graft polymer is preferably 1,500 to 50,000, more preferably 2,000 to 10,000, and still more preferably 2,000 to 3,000, from the viewpoint of low-temperature fixability of the toner.
In addition, a graft polymer can be used individually or in combination of 2 or more types. When using 2 or more types together, it is the value which calculated | required the mixture by the method as described in an Example.

(Side chain segment (A1) made of polyester resin)
The segment (A1) constituting the graft polymer used in the present invention is a segment made of a polyester resin.
Since the segment (A1) is composed of a polyester resin, it is preferably composed of a structural unit derived from an alcohol component and an acid component, and is preferably obtained as a polyester resin (a1) by condensation polymerization of the alcohol component and the acid component.

Examples of the alcohol component that becomes a constituent unit of the segment (A1) and is a raw material include aromatic diols, aliphatic diols, and trihydric or higher polyhydric alcohols. Aromatic diols are preferred from the viewpoints of enhancing copolymerizability with the resin, maintaining good toner storage stability, and improving toner chargeability.
As the aromatic diol, from the above viewpoint, a diol having a 2,2-bis (4-hydroxyphenyl) propane structure is preferable, and an alkylene oxide adduct of 2,2-bis (4-hydroxyphenyl) propane is more preferable. .

Specifically, the alkylene oxide adduct of 2,2-bis (4-hydroxyphenyl) propane is preferably a compound represented by the general formula (I).
As the alcohol component used as the raw material of the segment (A1), x R ^a O or y R ^b O in the general formula (I) may be the same or different. From the viewpoint of chargeability, they are preferably the same, and more preferably propyleneoxy groups.
From the viewpoint of uniformly forming a core-shell structure and thus improving the chargeability of the toner, the content of the propyleneoxy group is preferably 50 to 100 mol%, more preferably 80 to 100 mol% in the alkyleneoxy group. More preferably, it is substantially 100 mol%.
The alkylene oxide adduct of 2,2-bis (4-hydroxyphenyl) propane may be used alone or in combination of two or more, and a propylene oxide adduct of 2,2-bis (4-hydroxyphenyl) propane It is preferable to use a mixture of 2,2-bis (4-hydroxyphenyl) propane and an ethylene oxide adduct. The mixing molar ratio of the propylene oxide adduct of 2,2-bis (4-hydroxyphenyl) propane and the ethylene oxide adduct of 2,2-bis (4-hydroxyphenyl) propane is 50/50 to 99/1. Preferably, 60 / 40-80 / 20 is more preferable.

  From the viewpoint of chargeability and durability of the toner, the alkylene oxide adduct of 2,2-bis (4-hydroxyphenyl) propane is preferably 50 mol% or more, more preferably 70 mol% or more in the alcohol component. Preferably it is 80 mol% or more, More preferably, it contains substantially 100 mol%. In the present invention, the alkylene oxide adduct means the entire structure in which an alkyleneoxy group is added to 2,2-bis (4-hydroxyphenyl) propane.

Examples of the aliphatic diol include ethylene glycol, propylene glycol (1,2-propanediol), and hydrogenated bisphenol A.
Examples of the trihydric or higher polyhydric alcohol include glycerin, pentaerythritol, trimethylolpropane, and sorbitol. You may use the said alcohol component individually or in combination of 2 or more types.

Examples of the acid component that becomes a constituent unit of the segment (A1) and is a raw material include aromatic dicarboxylic acid, aliphatic dicarboxylic acid, alicyclic dicarboxylic acid, and trivalent or higher polyvalent carboxylic acid. From the viewpoint of enhancing the copolymerization with the addition polymerization resin constituting the main chain segment (A2) of the graft polymer, maintaining good storage stability of the toner, and improving the chargeability of the toner. An aromatic dicarboxylic acid and an aliphatic dicarboxylic acid are preferable, an aromatic carboxylic acid is more preferable, and an aromatic dicarboxylic acid and an aliphatic dicarboxylic acid are more preferably used in combination.
Examples of the aromatic dicarboxylic acid include terephthalic acid, isophthalic acid, and phthalic acid, and terephthalic acid is preferable from the viewpoint of chargeability.
Examples of the aliphatic dicarboxylic acid include fumaric acid, maleic acid, adipic acid, succinic acid, succinic acid having an alkyl group and / or alkenyl group, and fumaric acid is preferable from the viewpoint of low-temperature fixability.
Examples of the alicyclic dicarboxylic acid include cyclohexane dicarboxylic acid, decalin dicarboxylic acid, and tetrahydrophthalic acid.
Examples of the trivalent or higher polyvalent carboxylic acid include trimellitic acid and pyromellitic acid, and trimellitic acid is preferable.
The said carboxylic acid component may be individual or 2 or more types may be contained. The carboxylic acid includes anhydrides of these acids and alkyl esters having 1 to 3 carbon atoms.

  The segment (A1) in the present invention, that is, the polyester resin (a1) is a polycondensation reaction of an alcohol component and an acid component, preferably in the presence of a catalyst, preferably at 180 to 250 ° C., like the crystalline polyester (a). From the viewpoint of the efficiency of the polycondensation reaction, the catalyst is preferably a tin compound, a titanium compound, more preferably a tin compound, di (2-ethylhexanoic acid) tin, and dibutyl oxide. Tin is more preferable, and di (2-ethylhexanoic acid) tin is preferable from the viewpoint of heat-resistant storage stability of the obtained toner.

(Main chain segment (A2) made of addition polymerization resin)
The segment (A2) constituting the graft polymer of the present invention is a main chain segment made of an addition polymerization resin composed of a structural unit derived from an addition polymerizable monomer (a2) (hereinafter also referred to as monomer (a2)).
Examples of the addition polymerization resins include polystyrene, styrene derivative polymers, polyacrylic acid esters, styrene-acrylic copolymers, polyolefins, polyvinyl halides, polyvinyl esters, and the like. From the viewpoint of chargeability under humidity, polystyrene, a polymer of a styrene derivative, a polyacrylic acid ester, and a styrene-acrylic copolymer are preferable, and a polystyrene, a polymer of a styrene derivative, and a styrene-acrylic copolymer are more preferable. Polystyrene and styrene-acrylic copolymers are more preferred, and styrene-acrylic copolymers are more preferred.

Examples of the raw material addition polymerizable monomer (a2) which is a constituent unit of the addition polymerization resin include styrene, styrene derivatives, (meth) acrylic acid esters, olefins, halovinyls, vinyl esters, and the like. From the viewpoint of chargeability under high temperature and high humidity, styrene, styrene derivatives, and (meth) acrylic acid esters are preferable, and styrene and (meth) acrylic acid esters are more preferable. Among these, the raw material price of the monomer, the toner From the viewpoint of storage stability, styrene is more preferable, and it is more preferable to use styrene and (meth) acrylic acid ester in combination.
When styrene is used, the content of the structural unit derived from styrene is preferably 60 to 100 weight in the segment (A2) from the viewpoints of heat-resistant storage stability of toner, chargeability under high temperature and high humidity, and durability. %, More preferably 70 to 90% by weight, still more preferably 75 to 85% by weight.
Examples of the styrene derivative include methyl styrene, α-methyl styrene, β-methyl styrene, t-butyl styrene, chlorostyrene, chloromethyl styrene, methoxy styrene, styrene sulfonic acid or a salt thereof.
Examples of (meth) acrylic acid esters include alkyl (meth) acrylate (alkyl group having 1 to 18 carbon atoms), benzyl (meth) acrylate, and dimethylaminoethyl (meth) acrylate, and (meth) acrylic acid. Alkyl (alkyl group having 1 to 18 carbon atoms) is preferable, alkyl (meth) acrylate (alkyl group having 4 to 12 carbon atoms) is more preferable, alkyl (meth) acrylate (alkyl group having 8 to 12 carbon atoms) Is more preferable.
Examples of the olefin include ethylene, propylene, and butadiene.
Examples of halovinyl include vinyl chloride.
Examples of the vinyl ester include vinyl acetate and vinyl propionate.
The segment (A2) preferably contains a vinyl monomer having a carboxy group that becomes a bonding point with the polyester resin of the segment (A1). Among vinyl monomers having a carboxy group, acrylic acid and methacrylic acid are preferable.

The weight ratio [segment (A1) / segment (A2)] of the side chain segment (A1) and the main chain segment (A2) constituting the graft polymer achieves both low-temperature fixability, chargeability and heat-resistant storage stability of the toner. From the viewpoint of improving the low-temperature fixability, it is preferably 95/55 to 55/45, preferably 85/15 to 55/45, more preferably 80/20 to 60/40, and particularly preferably 75 / 25-65 / 35.
It is considered that a strong core-shell structure can be maintained when there are more segments (A1) than segments (A2).

(Method for producing graft polymer)
The graft polymer is obtained by subjecting a raw material monomer of the polyester resin (a1) to a polycondensation reaction in the presence of an addition polymerization resin having a carboxy group, and after obtaining an addition polymerization resin having a carboxy group and a polyester resin (a1), Any method such as a method for condensing the toner may be used, but the latter is preferable from the viewpoint of operation efficiency and heat-resistant storage stability of the obtained toner. Especially, it is preferable to obtain by the method which has the following process (a-1) and (a-2).
Step (a-1): Step of obtaining an addition polymerization resin having a carboxy group by addition polymerization reaction from the addition polymerizable monomer (a2) and a vinyl monomer having a carboxy group Step (a-2): The addition polymerization Mixing and condensing polyester resin and polyester resin (a1)

<Step (a-1)>
Step (a-1) is a step of obtaining an addition polymerization resin having a carboxy group from the addition polymerizable monomer (a2) and a vinyl monomer having a carboxy group by an addition polymerization reaction.
In this step, the polymerization initiator used is preferably one that dissolves in the addition polymerizable monomer (a2), and dibutyl peroxide is preferred. The reaction temperature may be adjusted depending on the kind of the polymerization initiator, and is preferably 100 to 180 ° C, more preferably 140 to 170 ° C, from the viewpoint of efficiently performing the addition polymerization reaction.

The vinyl monomer having a carboxy group is a compound having a carboxy group and an ethylenically unsaturated bond in the molecule, and is a bireactive monomer capable of both addition polymerization reaction and condensation polymerization reaction. Specifically, acrylic acid, methacrylic acid, crotonic acid, tiglic acid, 2-pentenoic acid, 4-pentenoic acid, 2-methyl-2-pentenoic acid, 4-methyl-2-pentenoic acid, 2-hexenoic acid, 5-hexenoic acid and the like can be mentioned, among which acrylic acid and methacrylic acid are preferable from the viewpoint of polymerizability.
The amount of the vinyl monomer having a carboxy group is selected from the viewpoint of the dispersibility of the addition polymerization resin in the polyester resin (a1) and the reaction control of the addition polymerization reaction and the condensation polymerization reaction. 1-40 mol% is preferable with respect to the carboxylic acid component whole quantity which is these, and 5-30 mol% is more preferable.
In addition, since this process is performed in the following process (2) in as uniform a state as possible, it is preferably performed in the presence of the raw material monomer of the polyester resin (a1) or the polyester resin (a1). The presence of the polyester resin (a1) It is preferable to carry out below.

<Process (a-2)>
Step (a-2) is a step of obtaining the graft polymer by mixing and condensing the addition polymerization resin and the polyester resin (a1).
The polyester resin (a1) is preferably reacted in the presence of a catalyst similar to that used in the condensation polymerization, and the reaction temperature is preferably 150 to 250 ° C, and preferably 170 to 240 ° C. More preferably, it is 175-220 degreeC.

In addition, in the range which does not inhibit the effect of this invention, although a process (a-1) and (a-2) may be performed simultaneously or in parallel, a process (a-2) is carried out after a process (a-1). ) Is preferable.
In addition, since the condensation reaction of the polyester resin (a1) also proceeds when the condensation of the addition polymerization resin and the polyester resin (a1) in the step (a-2) is performed, in the step (a-2), the polyester resin Of the raw material monomers of (a1), it is preferable to add a highly reactive monomer and further perform polycondensation.
Examples of the highly reactive monomer used here include fumaric acid and trimellitic acid.

[Method for producing toner for electrophotography]
The method for producing an electrophotographic toner of the present invention includes the following steps (1) to (3).
Step (1): Resin particles (A) containing crystalline polyester (a) obtained by polycondensation of α, ω-alkanediol having 4 to 12 carbon atoms and aliphatic dicarboxylic acid having 8 to 12 carbon atoms And a step of agglomerating release agent particles having a melting point of 60 to 90 ° C. to obtain aggregated particles (1) Step (2): The aggregated particles (1) obtained in Step (1) are made of a polyester resin. Step of adding aggregated particles (2) by adding resin particles (B) containing a graft polymer composed of side chain segments (A1) and main chain segments (A2) made of addition polymerization resin Step (3) : A step of maintaining the temperature of the system containing the agglomerated particles (2) at a temperature of 10 ° C. or lower than the glass transition point of the graft polymer and fusing them to obtain core-shell particles. Explanation of each component used Light up.

[Resin particles (A)]
In the present invention, the resin particles (A) contain the crystalline polyester (a), and the content of the crystalline polyester (a) in the resin particles (A) improves the low-temperature fixability of the toner, From the viewpoint of preventing hot offset, the resin constituting the resin particles (A) is preferably 1 to 50% by weight, preferably 10 to 50% by weight, more preferably 13 to 30% by weight, and particularly preferably 13 to 20% by weight. preferable.
Preferred crystalline polyester (a) is as described above.
The resin particles (A) preferably further contain an amorphous polyester (b) from the viewpoint of improving storage stability and chargeability while maintaining low-temperature fixability of the toner and preventing hot offset.
Preferred amorphous polyester (b) is as described above. From the viewpoint of increasing affinity with crystalline polyester and improving low-temperature fixability, alkyl succinic acid having a branched alkyl group having 9 to 14 carbon atoms and It is preferably obtained by condensation polymerization of an acid component containing 20 to 50 mol% of an alkenyl succinic acid having an alkenyl group having 9 to 14 carbon atoms and an alcohol component.

In addition, the resin particles (A) may be particles composed only of a resin or may be colorant-containing resin particles containing a colorant. From the viewpoint of sharpening the particle size distribution of the toner, the colorant It is preferable that it is a coloring agent containing resin particle containing a coloring agent.
When the resin particles (A) are colorant-containing resin particles, the content of the colorant is 1 to 20 weights with respect to 100 parts by weight of the resin constituting the resin particles (A) from the viewpoint of toner image density. Part is preferable, and 5 to 10 parts by weight is more preferable.

(Coloring agent)
The colorant used in the present invention may be used as a colorant particle in an aqueous medium by surface treatment or use of a dispersant, or may be used by being contained in resin particles such as resin particles (A). From the viewpoint of sharpening the particle size distribution of the toner, the resin particles (A) are preferably used.
As the colorant, pigments and dyes are used, and pigments are preferable from the viewpoint of image density of the toner.
Specific examples of the pigment include carbon black, inorganic composite oxide, chrome yellow, benzidine yellow, brilliantamine 3B, brilliantamine 6B, Bengal, aniline blue, ultramarine blue, copper phthalocyanine, phthalocyanine green, and the like. Phthalocyanine is preferred.
Specific examples of the dye include acridine series, azo series, benzoquinone series, azine series, anthraquinone series, indico series, phthalocyanine series, and aniline black series.
A coloring agent can be used individually by 1 type or in combination of 2 or more types.

(Production of resin particles (A))
The resin particles (A) are produced by a method in which the above-mentioned optional components such as the resin containing the crystalline polyester (a) and the colorant are dispersed in an aqueous medium to obtain a dispersion containing the resin particles (A). Is preferred.
Examples of a method for obtaining a dispersion include a method in which a resin or the like is added to an aqueous medium and a dispersion treatment is performed using a disperser or the like, and a method in which an aqueous medium is gradually added to a resin or the like to perform phase inversion emulsification. From the viewpoint of low-temperature fixability of the toner, a method using phase inversion emulsification is preferred. Hereinafter, a method by phase inversion emulsification will be described.

First, the resin containing the crystalline polyester (a), the alkaline aqueous solution, and the optional components such as the colorant are melted and mixed to obtain a resin mixture.
When the resin containing the crystalline polyester (a) is composed of a plurality of resins, a mixture of the crystalline polyester (a) and other resins may be used in advance, but the alkaline aqueous solution and the optional components may be used. It may be obtained by adding at the same time when adding, melting and mixing. For example, when the resin containing the crystalline polyester (a) contains the amorphous polyester (b), the crystalline polyester (a), the amorphous polyester (b), the alkaline aqueous solution, and the above optional components A method of melting and mixing the toner to obtain a resin mixture is preferable from the viewpoint of low-temperature fixability of the toner.
In mixing, it is preferable to add a surfactant from the viewpoint of the emulsion stability of the resin.

  Examples of the alkali in the alkaline aqueous solution include hydroxides of alkali metals such as potassium hydroxide and sodium hydroxide, and ammonia. From the viewpoint of improving the dispersibility of the resin, potassium hydroxide and sodium hydroxide are preferable. . Moreover, 1-30 weight% is preferable, as for the density | concentration of the alkali in aqueous alkali solution, 1-25 weight% is more preferable, and 1.5-20 weight% is still more preferable.

Examples of the surfactant include nonionic surfactants, anionic surfactants, cationic surfactants, etc. Among them, nonionic surfactants are preferable, and nonionic surfactants and anionic surfactants or It is more preferable to use a cationic surfactant in combination, and it is more preferable to use a nonionic surfactant and an anionic surfactant in combination from the viewpoint of sufficiently emulsifying the resin.
When a nonionic surfactant and an anionic surfactant are used in combination, the weight ratio of the nonionic surfactant to the anionic surfactant (nonionic surfactant / anionic surfactant) is sufficient for the resin. From the viewpoint of emulsifying, 0.3 to 10 is preferable, 0.5 to 5 is preferable, and 0.7 to 2 is more preferable.

Nonionic surfactants include polyoxyethylene nonylphenyl ether, polyoxyethylene oleyl ether, polyoxyethylene alkyl aryl ethers such as polyoxyethylene lauryl ether or polyoxyethylene alkyl ethers, polyethylene glycol monolaurate, Examples include polyoxyethylene fatty acid esters such as polyethylene glycol monostearate and polyethylene glycol monooleate, and oxyethylene / oxypropylene block copolymers. Among them, from the viewpoint of emulsion stability of the resin, polyoxyethylene alkyl ether Are preferred.
Specific examples of the anionic surfactant include sodium dodecyl benzene sulfonate, sodium dodecyl sulfate, sodium alkyl ether sulfate, etc. Among them, from the viewpoint of emulsion stability of the resin, sodium dodecyl benzene sulfonate, alkyl ether sulfate Sodium is preferred.
Specific examples of the cationic surfactant include alkyltrimethylammonium chloride.

  The content of the surfactant is preferably 20 parts by weight or less, more preferably 15 parts by weight or less, still more preferably 0.1 to 10 parts by weight, with respect to 100 parts by weight of the resin constituting the resin particles (A). 0.5-10 weight part is still more preferable.

  As a method for obtaining a resin mixture, a resin containing crystalline polyester (a), an aqueous alkali solution, and the above optional components, preferably a surfactant, are placed in a container, and the resin is melted uniformly while stirring with a stirrer. It is preferable to mix them.

  When the resin containing the crystalline polyester (a) contains the amorphous polyester (b), the temperature at which the resin is melted and mixed is preferably equal to or higher than the glass transition point, to obtain homogeneous resin particles. Therefore, the melting point of the crystalline polyester (a) is more preferable.

Next, an aqueous medium is added to the resin mixture and phase inversion is performed to obtain a dispersion containing resin particles (A).
The aqueous medium preferably contains water as a main component, and from the viewpoint of environmental properties, the water content in the aqueous medium is preferably 80% by weight or more, more preferably 90% by weight or more, and further 95% by weight or more. Preferably, substantially 100% by weight is more preferable. As water, deionized water or distilled water is preferably used.
As components other than water, organic solvents that dissolve in water such as alkyl alcohols having 1 to 5 carbon atoms; dialkyl (carbon numbers 1 to 3) ketones such as acetone and methyl ethyl ketone; and cyclic ethers such as tetrahydrofuran are used. Among these, from the viewpoint of preventing mixing into the toner, an alkyl alcohol having 1 to 5 carbon atoms that does not dissolve the polyester is preferable, and methanol, ethanol, isopropanol, and butanol are more preferable.

  The temperature at which the aqueous medium is added is preferably equal to or higher than the glass transition point of the amorphous polyester (b) when the resin containing the crystalline polyester (a) contains the amorphous polyester (b). From the viewpoint of obtaining resin particles, the melting point of the crystalline polyester (a) is more preferable.

  The addition rate of the aqueous medium is from 0.1 to 50 parts by weight / 100 parts by weight of the resin constituting the resin particles (A) until the phase inversion is completed from the viewpoint of making the resin particles have a small particle size. Preferably 0.1 to 30 parts by weight / minute, more preferably 0.5 to 10 parts by weight / minute, and 0.5 to 5 parts by weight / minute. Is more preferable. There is no restriction | limiting in the addition rate of the aqueous medium after phase inversion.

  The amount of the aqueous medium used is preferably 100 to 2000 parts by weight, and 150 to 1500 parts by weight with respect to 100 parts by weight of the resin constituting the resin particles (A) from the viewpoint of obtaining uniform aggregated particles in the subsequent aggregation step. More preferred is 150 to 500 parts by weight. From the viewpoint of the stability and ease of handling of the obtained resin particle dispersion, the solid content concentration is preferably 7 to 50% by weight, more preferably 10 to 40% by weight, still more preferably 20 to 40% by weight, More preferably, it is 25 to 35% by weight. In addition, solid content is the total amount of non-volatile components, such as resin and surfactant.

The volume median particle diameter (D ₅₀ ) of the resin particles (A) in the dispersion containing the obtained resin particles (A) is preferably 0.02 to 2 μm. From the viewpoint of obtaining a high-image toner, 0.02 to 1.5 μm is preferable, 0.05 to 1 μm is more preferable, 0.05 to 0.5 μm is still more preferable, and 0.1 to 0.3 μm is still more preferable. Here, “volume median particle size (D ₅₀ )” means a particle size at which the cumulative volume frequency calculated by the volume fraction is 50% when calculated from the smaller particle size. The measuring method is as shown in the examples.
Further, the coefficient of variation (CV value) (%) of the particle size distribution of the resin particles is preferably 40% or less, more preferably 35% or less, still more preferably 30% or less, from the viewpoint of obtaining a high-image toner. 28% or less is more preferable. The CV value is a value represented by the following formula, and is specifically obtained by the method described in the examples.
CV value (%) = [standard deviation of particle size distribution (μm) / volume average particle size (μm)] × 100

[Releasing agent particles]
The release agent particles preferably contain a surfactant from the viewpoint of aggregation. In the case of using the surfactant, the content is preferably 0.01 to 10 parts by weight with respect to 100 parts by weight of the release agent, from the viewpoint of aggregation properties and chargeability of the obtained toner, and preferably 0.1 to 5 parts by weight. Part by weight is more preferred.
As the surfactant, polycarboxylate is preferable, sodium polycarboxylate is preferable, and sodium acrylate-sodium maleate copolymer is preferable. These are preferably used as an aqueous solution.
The volume median particle size of the release agent particles is preferably from 0.1 to 1 μm, more preferably from 0.1 to 0.7 μm, more preferably from 0.1 to 0.7 μm from the viewpoint of preventing chargeability and hot offset of the obtained toner. 5 μm is more preferable.
The CV value of the release agent particles is preferably 15 to 50%, more preferably 15 to 40%, and still more preferably 15 to 35%, from the viewpoint of the chargeability of the obtained toner.

(Manufacture of release agent particles)
The release agent particles are preferably obtained as a dispersion of release agent particles by dispersing the release agent in an aqueous medium.
The dispersion of the release agent particles is preferably obtained by dispersing the release agent and the aqueous medium using a disperser in the presence of a surfactant at a temperature equal to or higher than the melting point of the release agent. As the disperser to be used, a homogenizer, an ultrasonic disperser or the like is preferable.
As the aqueous medium used in the present production, those used when obtaining a resin mixture are preferably used.

[Resin particles (B)]
In the present invention, the resin particles (B) are composed of a side chain segment (A1) made of a polyester resin and a main chain segment (A2) made of an addition polymerization resin from the viewpoint of storage stability and chargeability of the toner. It contains a graft polymer.
The preferred range of the graft polymer composed of the side chain segment (A1) made of a polyester resin and the main chain segment (A2) made of an addition polymerization resin is as described above.

(Production of resin particles (B))
The resin particles (B) are obtained by using the graft polymer in the same manner as the above-described method for producing the resin particles (A), that is, adding an aqueous medium to the graft polymer, phase-inversion, and resin particles (B). From the viewpoint of heat-resistant storage stability and chargeability of the obtained toner, the graft polymer is dissolved in an organic solvent, and water is added to perform phase inversion emulsification. It is preferable to obtain, and it is more preferable to obtain by the method including the following steps (B-1) and (B-2).
Step (B-1): A step of dissolving the graft polymer in an organic solvent and further adding a neutralizing agent to obtain a graft polymer solution.
Step (B-2): A step of obtaining an aqueous dispersion of resin particles (B) by adding water to the solution obtained in the step (B-1).

<Process (B-1)>
Step (B-1) is a step of dissolving the graft polymer in an organic solvent and further adding a neutralizing agent to obtain a graft polymer solution.
The organic solvent is preferably a ketone solvent or toluene, more preferably a ketone solvent, from the viewpoint of the solubility of the graft polymer and the volatility of the solvent during drying.
Examples of the ketone solvent include acetone, methyl ethyl ketone, diethyl ketone, dipropyl ketone, methyl isobutyl ketone, and methyl isopropyl ketone. Among these, methyl ethyl ketone is preferable from the viewpoint of the solubility of the graft polymer and the ease of distilling off the solvent.
Examples of the method for dissolving the graft polymer in an organic solvent include a method in which the graft polymer and the organic solvent are mixed and dissolved by stirring at room temperature or in a heated state.

The neutralizing agent is used to ionize the carboxyl group of the graft polymer, add water in the next step, and then invert to the aqueous system.
As a neutralizing agent, the same compound as what was used by manufacture of a resin particle (A) can be mentioned, Sodium hydroxide is preferable. These neutralizing agents may be used in an amount that can neutralize at least the acid value of the graft polymer.
The neutralizing agent is usually added at a temperature below the boiling point of the organic solvent at 1 atm.
In the step (B-1), a resin other than the graft polymer can be used in combination as long as the effects of the present invention are not impaired.

<Process (B-2)>
Step (B-2) is a step in which water is added to the solution obtained in step (B-1) to obtain an aqueous dispersion of resin particles (B).
Specifically, for example, a reactor equipped with a stirrer, a reflux condenser, a thermometer, a dropping funnel, and a nitrogen gas introduction pipe is prepared, and water is added to the solution obtained in the step (B-1). Invert to the aqueous phase. Preferably, after adding water, the organic solvent is distilled off and the phase is changed to an aqueous phase. Moreover, as water used here, deionized water etc. are mentioned, for example.

The aqueous dispersion obtained in this step may contain components other than water as long as the effects of the present invention are not impaired.
Examples of components other than water used include organic solvents that dissolve in water, such as methanol, ethanol, isopropanol, butanol, acetone, methyl ethyl ketone, and tetrahydrofuran.
As a dispersion medium for the aqueous dispersion, a medium containing water as a main component, that is, a medium containing 50% or more of water is preferable. From the viewpoint of environmental properties, the content of water in the medium is preferably 80% by weight or more, more preferably 90% by weight or more, and still more preferably 100% by weight.

From the viewpoint of obtaining homogeneous core-shell particles, the resin particles in the aqueous dispersion preferably have a volume-median particle size (D ₅₀ ) of 20 to 1000 nm, more preferably 50 to 500 nm, still more preferably 80 to 200 nm, more preferably 100 to 150 nm.

[Surfactant (A)]
In step (3) in the method for producing an electrophotographic toner of the present invention, it is preferable to use a surfactant (A).
Examples of the surfactant (A) used in the step (3) include nonionic surfactants, anionic surfactants, and cationic surfactants. Especially, the fusion of the aggregated particles is effectively prevented. From the viewpoint of obtaining a toner having a sharp particle size distribution, nonionic surfactants and anionic surfactants are preferred, and anionic surfactants are more preferred.

As the anionic surfactant, an anionic surfactant having a polyethylene glycol moiety having an average added mole number of ethylene oxide of 5 to 100 is preferable. The average added mole number of the ethylene oxide is preferably 5 to 100 moles from the viewpoint of improving the stability of the aggregated particles and the fusing property of the resin particles, and improving the chargeability and heat resistant storage stability of the obtained toner. 6-50 mol is more preferable, 9-30 mol is more preferable, 11-20 mol is still more preferable, and 12-15 mol is still more preferable.
Moreover, if the average added mole number of a polyethylene glycol part is the said range, the part derived from alkylene oxides other than ethylene oxide may be included in the polyethylene glycol part in a block or randomly. Preferable alkylene oxide other than ethylene oxide includes propylene oxide.
Preferable anionic surfactants include sulfate ester salts and sulfonate salts having an average addition mole number of ethylene oxide of 5 to 100, and sulfate ester salts are preferred.

  The sulfate ester salt is preferably a sulfate ester salt represented by the following general formula (1), polyoxyethylene alkyl ether sulfate, polyoxyethylene polyoxypropylene alkyl ether sulfate or the like, represented by the following general formula (1). Sulfuric acid ester salts and polyoxyethylene alkyl ether sulfates are more preferable, and sulfuric acid ester salts represented by the following general formula (1) are more preferable.

（式中、Ｒ¹は、水素原子又は炭素数１〜１２のアルキル基を表し、Ｒ²は、水素原子又はメチル基を表し、ｍ１は平均値が１〜４であり、Ａ¹Ｏはエチレンオキシ基及び／又はプロピレンオキシ基を表し、ｎ１は平均値が５〜１００であり、Ｍはアンモニウム、テトラアルキルアンモニウム、アルカリ金属を表す。）

(In the formula, R ¹ represents a hydrogen atom or an alkyl group having 1 to 12 carbon atoms, R ² represents a hydrogen atom or a methyl group, m1 has an average value of 1 to 4, and A ¹ O represents ethylene. Represents an oxy group and / or a propyleneoxy group, n1 has an average value of 5 to 100, and M represents ammonium, tetraalkylammonium, or an alkali metal.)

R ¹ represents a hydrogen atom or an alkyl group having 1 to 12 carbon atoms, and from the viewpoint of improving the chargeability and heat resistant storage stability of the toner, a hydrogen atom or an alkyl group having 1 to 3 carbon atoms is preferable. A group is more preferable, and a hydrogen atom is still more preferable.

R ² represents a hydrogen atom or a methyl group and is preferably a methyl group from the viewpoint of improving the stability of the aggregated particles and the fusing property of the resin particles and improving the chargeability and heat-resistant storage stability of the obtained toner. The plurality of R ² may be the same or different, but are preferably the same.
The sulfate ester salt represented by the general formula (1) may be a mixture of compounds in which m1 is any one of 1 to 4, and m1 has an average value of 1 to 4 and is charged with toner. And from a viewpoint of improving heat-resistant storage stability, 2-3 are preferable and 2 is more preferable.
M1 has an average value of preferably 2 to 3 when R ² is hydrogen atom, 3 is more preferable.
M1 is preferably an average value of 1 to 2 when R ² is methyl group, 2 is more preferable.

n1 represents the average added mole number of the alkyleneoxy group A ¹ O. n1 has an average value of 5 to 100 mol and 6 to 50 mol from the viewpoint of improving the stability of the aggregated particles and the fusing property of the resin particles and improving the chargeability and heat-resistant storage stability of the obtained toner. Is preferable, 9-30 mol is more preferable, 11-20 mol is still more preferable, and 12-15 mol is still more preferable.
A ¹ O represents an ethyleneoxy group and / or a propyleneoxy group, and A ¹ represents an ethylene group (—CH ₂ CH ₂ —) and / or a propylene group (—CH ₂ CH (CH ₃ ) — or —CH (CH ₃₎ CH ₂ -) represents a. A ¹ preferably contains an ethylene group or an ethylene group and a propylene group, and is preferably an ethylene group. When A ¹ O is a propyleneoxy group, the direction of the propylene group is not particularly limited.
When A ¹ is an ethylene group, n1 has an average value of 5 from the viewpoint of improving the stability of the aggregated particles and the fusing property of the resin particles and improving the chargeability and heat-resistant storage stability of the resulting toner. It is -100 mol, 6-50 mol is preferable, 9-30 mol is more preferable, 11-20 mol is still more preferable, 12-15 mol is still more preferable.

  M is ammonium, tetraalkylammonium, or alkali metal from the viewpoint of the particle size distribution of the obtained toner, preferably ammonium or alkali metal, and more preferably ammonium.

  Preferable sulfate ester salts include polyoxyethylene (5-100) distyrenated phenyl ether monosulfate ammonium salt, polyoxypropylene (5-95) polyoxyethylene (95-5) distyrenated phenyl ether monosulfate ammonium salt And polyoxyethylene (5-100) tribenzylated phenyl ether sulfate ammonium salt.

（式中、Ｒ³は、水素原子又は炭素数１〜１２のアルキル基を表し、Ｒ⁴は、水素原子又はメチル基を表し、ｍ２は平均値が１〜４であり、Ａ²Ｏはエチレンオキシ基及び／又はプロピレンオキシ基を表し、ｎ２は平均値が５〜１００である。） Examples of nonionic surfactants include polyoxyethylene alkylaryl ethers, polyoxyethylene alkyl ethers, polyoxyethylene fatty acid esters, and the like, and nonionic surfactants represented by the following general formula (2) Is preferred.

(In the formula, R ³ represents a hydrogen atom or an alkyl group having 1 to 12 carbon atoms, R ⁴ represents a hydrogen atom or a methyl group, m2 has an average value of 1 to 4, and A ² O represents ethylene. Represents an oxy group and / or a propyleneoxy group, and n2 has an average value of 5 to 100.)

R ³ represents a hydrogen atom or an alkyl group having 1 to 12 carbon atoms, and from the viewpoint of improving the chargeability and heat resistant storage stability of the toner, a hydrogen atom or an alkyl group having 1 to 3 carbon atoms is preferable. A group is more preferable, and a hydrogen atom is still more preferable.

R ⁴ represents a hydrogen atom or a methyl group and is preferably a methyl group from the viewpoint of improving the stability of the aggregated particles and the fusing property of the resin particles and improving the chargeability and heat-resistant storage stability of the resulting toner. The plurality of R ⁴ may be the same or different, but are preferably the same.
The nonionic surfactant represented by the general formula (2) may be a mixture of compounds in which m2 is any one of 1 to 4, and m2 has an average value of 1 to 4, From the viewpoint of improving the chargeability and heat-resistant storage stability, 2 to 3 is preferable and 2 is more preferable.
When R ⁴ is a hydrogen atom, the average value of m is preferably 2 to 3, and more preferably 3.
In the case where R ⁴ is a methyl group, the average value of m is preferably 1 to 2, and more preferably 2.

n2 represents the average added mole number of the alkyleneoxy group A ² O. n2 has an average value of 5 to 100 mol and 6 to 50 mol from the viewpoint of improving the stability of the aggregated particles and the fusing property of the resin particles, and improving the chargeability and heat-resistant storage stability of the obtained toner. Is preferable, 9-30 mol is more preferable, 11-20 mol is still more preferable, and 12-15 mol is still more preferable.
A ² O represents an ethyleneoxy group and / or a propyleneoxy group, and A ² represents an ethylene group (—CH ₂ CH ₂ —) and / or a propylene group (—CH ₂ CH (CH ₃ ) — or —CH (CH ₃₎ CH ₂ -) represents a. A ² preferably contains an ethylene group or an ethylene group and a propylene group, and preferably an ethylene group. Note that when A ² O is a propyleneoxy group, the orientation of the propylene group is not particularly limited.
When A ² is an ethylene group, n2 has an average value of 5 to 5 from the viewpoint of improving the stability of the aggregated particles and the fusing property of the resin particles, and improving the chargeability and heat-resistant storage stability of the obtained toner. It is 100 mol, 6-50 mol is preferable, 9-30 mol is more preferable, 11-20 mol is still more preferable, 12-15 mol is still more preferable.
The HLB of the nonionic surfactant represented by the general formula (2) is preferably 10-18, more preferably 12-15.

Preferred nonionic surfactants represented by the general formula (2) include polyoxyethylene (5-100) distyrenated phenyl ether, polyoxypropylene (5-95) polyoxyethylene (95-5) distyrenated phenyl. And ethers and polyoxyethylene (5-100) tribenzylated phenyl ethers.
However, the number in parenthesis shows the average added mole number of polyoxyalkylene.

Examples of commercially available nonionic surfactants represented by the general formula (2) include polyoxyethylene (13) distyrenated phenyl ether (trade name: Emulgen A-60, manufactured by Kao Corporation), polyoxyethylene. (18) Distyrenated phenyl ether (trade name: Emulgen A-90, manufactured by Kao Corporation), polyoxyethylene (15) tribenzylated phenyl ether (trade name: Emulgen B-66, manufactured by Kao Corporation) It is done.
Specific examples of the cationic surfactant include alkyltrimethylammonium chloride.
Next, each process of the manufacturing method of this invention is demonstrated.

[Step (1)]
In step (1), resin particles containing crystalline polyester (a) obtained by polycondensation of α, ω-alkanediol having 4 to 12 carbon atoms and aliphatic dicarboxylic acid having 8 to 12 carbon atoms (A) ) And release agent particles having a melting point of 60 to 90 ° C. to obtain aggregated particles (1).

In this step, first, the resin particles (A) and the release agent particles are mixed in an aqueous medium to obtain a mixed dispersion.
In addition, although it is preferable to mix a colorant as an arbitrary component, the colorant may be mixed as a separate particle by itself, or may be contained in the resin particles (A). Therefore, it is preferably contained in the resin particles (A).
In this step, resin particles other than the resin particles (A) may be mixed.
There is no restriction | limiting in order of mixing, You may add any in order and may add simultaneously.

In the mixed dispersion, the resin particles (A) are preferably 10 to 40 parts by weight, and more preferably 20 to 30 parts by weight. The aqueous medium is preferably 60 to 90 parts by weight, and more preferably 70 to 80 parts by weight.
Moreover, 1-20 weight part is preferable with respect to 100 weight part of resin which comprises a resin particle (A) from a viewpoint of image density, and, as for a coloring agent, 3-15 weight part is more preferable. The release agent particles are preferably 1 to 20 parts by weight, more preferably 2 to 15 parts by weight, based on 100 parts by weight of the total of the resin and the colorant, from the viewpoint of toner releasability and chargeability.
The mixing temperature is preferably 0 to 40 ° C. from the viewpoint of aggregation control.

Next, the particles in the mixed dispersion are aggregated to obtain a dispersion of aggregated particles (1). It is preferable to add a flocculant for efficient aggregation.
As the flocculant, a quaternary salt cationic surfactant, an organic flocculant such as polyethyleneimine; and an inorganic flocculant such as an inorganic metal salt, an inorganic ammonium salt, or a bivalent or higher metal complex are used.
Examples of the inorganic metal salt include metal salts such as sodium sulfate, sodium chloride, calcium chloride and calcium nitrate, and inorganic metal salt polymers such as polyaluminum chloride and polyaluminum hydroxide. Examples of the inorganic ammonium salt include ammonium sulfate, ammonium chloride, ammonium nitrate and the like, and ammonium sulfate is more preferable.
The use amount of the flocculant is preferably 50 parts by weight or less, more preferably 40 parts by weight or less, and further preferably 30 parts by weight with respect to 100 parts by weight of the resin constituting the resin particles (A), from the viewpoint of chargeability of the toner. Less than parts by weight. From the viewpoint of the cohesiveness of the resin particles, the amount is preferably 1 part by weight or more, more preferably 3 parts by weight or more, and still more preferably 5 parts by weight or more with respect to 100 parts by weight of the resin constituting the resin particles (A). is there. In consideration of the above points, the amount of the monovalent salt used is preferably 1 to 50 parts by weight, more preferably 3 to 40 parts by weight with respect to 100 parts by weight of the resin constituting the resin particles (A). More preferably, it is 5-30 weight part.

  As an aggregating method, an aggregating agent is preferably added dropwise as an aqueous solution to a container containing a mixed dispersion. The flocculant may be added at one time, or may be added intermittently or continuously. However, it is preferable to perform sufficient stirring at the time of addition and after completion of the addition. From the viewpoint of aggregation control and shortening of toner production time, the dropping time of the aggregating agent is preferably 1 to 120 minutes. Moreover, 0-50 degreeC is preferable from a viewpoint of aggregation control.

  The volume median particle size of the obtained agglomerated particles (1) is preferably 1 to 10 μm, more preferably 2 from the viewpoint of reducing the particle size and reducing the amount of scattering of the resulting toner in a printing machine such as a printer. It is -9 micrometers, More preferably, it is 3-6 micrometers. The CV value is preferably 30% or less, more preferably 28% or less, and still more preferably 25% or less.

[Step (2)]
In step (2), the aggregated particles (1) obtained in step (1) are composed of a side chain segment (A1) made of a polyester resin and a main chain segment (A2) made of an addition polymerization resin. This is a step of adding the resin particles (B) containing, to obtain aggregated particles (2).
In this step, the dispersion of resin particles (B) is added to the dispersion of aggregated particles (1) obtained in step (1), and the resin particles (B) are further adhered to the aggregated particles (1). It is preferable to obtain aggregated particles (2).

Before adding the dispersion containing the resin particles (B) (resin particle (B) dispersion) to the dispersion containing the aggregated particles (1) (aggregated particles (1) dispersion), the aggregated particles (1) An aqueous medium may be added to the dispersion for dilution, and it is preferable to add an aqueous medium. By adding the aqueous medium, the resin particles (B) can be more uniformly attached to the aggregated particles (1).
When the resin particle (B) dispersion is added to the aggregated particle (1) dispersion, the aggregating agent may be used in order to efficiently attach the resin particle (B) to the aggregated particle (1).
As a preferable addition method in the case of adding the resin particle (B) dispersion to the aggregated particle (1) dispersion, a method of simultaneously adding the coagulant and the resin particle (B) dispersion, the coagulant and the resin particle (B ) A method of alternately adding the dispersion liquid, and a method of adding the resin particle (B) dispersion liquid while gradually raising the temperature of the aggregated particle (1) dispersion liquid. By doing in this way, the cohesiveness fall of the aggregated particle (1) and the resin particle (B) by the coagulant | flocculant density | concentration fall can be prevented. From the viewpoint of toner productivity and manufacturing simplicity, it is preferable to add the resin particle (B) dispersion while gradually increasing the temperature of the aggregated particle (1) dispersion.

  The temperature in the system in this step is 5 ° C. or more lower than the melting point of the crystalline polyester (a) contained in the resin particles (A) from the viewpoint of low-temperature fixability of the toner, storage stability, and reduction in the amount of scattering. It is preferably 3 ° C. or more lower than the glass transition point of the graft polymer, more preferably 5 ° C. or more. When the aggregated particles (2) are produced in this temperature range, the low-temperature fixability and storage stability of the obtained toner are improved. The reason for this is not clear, but because the agglomeration of the aggregated particles (2) does not occur, the generation of coarse particles is suppressed, and the crystallinity of the crystalline polyester (a) can be maintained. Conceivable.

  The addition amount of the resin particles (B) is a weight ratio of the resin particles (B) to the resin particles (A) (resin particles (B) / The amount of the resin particles (A)) is preferably 0.3 to 1.5, more preferably 0.3 to 1.0, and still more preferably 0.35 to 0.75.

  The resin particle (B) dispersion may be added continuously over a certain period of time, may be added at a time, or may be added in a plurality of divided portions. It is preferable to add them continuously or in several divided portions. By adding as described above, the resin particles (B) are likely to selectively adhere to the aggregated particles (1). Among these, it is preferable to add continuously over a certain time from the viewpoint of promoting selective adhesion and the efficiency of production. The time for continuous addition is preferably 1 to 10 hours, more preferably 3 to 8 hours, from the viewpoint of obtaining uniform aggregated particles (2) and from the viewpoint of shortening the production time.

The volume median particle size of the aggregated particles (2) obtained in the step (2) is preferably 1 to 10 μm, more preferably 2 to 10 μm, and further preferably 3 to 9 μm from the viewpoint of improving the image quality of the toner. 4 to 6 μm is preferable.
In step (2), from the viewpoint of obtaining homogeneous core-shell particles, the pH of the aggregated particle (1) dispersion is preferably adjusted to 6.5 to 8.0, more preferably 6.5 to 7.5. It is preferable to add the resin particles (B).

[Step (3)]
Step (3) is a step of obtaining core-shell particles by maintaining the temperature of the system containing the agglomerated particles (2) at a temperature of 10 ° C. lower than the glass transition point of the graft polymer and fusing them.
In this step, the agglomerated particle (2) dispersion obtained in step (2) is kept as it is at a temperature of 10 ° C. or lower than the glass transition point of the graft polymer, and is fused. Although the pH at 25 ° C. of the aqueous mixture containing the aggregated particles (2) and the surfactant (A) is adjusted to 2.0 to 6.4 and / or while adjusting The core-shell particles may be obtained by maintaining the temperature of the system containing the agglomerated particles (2) at a temperature of 10 ° C. lower than the glass transition point of the graft polymer and fusing them.

In this step, it is preferable to add the surfactant (A) first, and it is preferable to add an acid in order to adjust the pH of the aqueous mixture at 25 ° C. to 2.0 to 6.4.
The acid used in this step is preferably an inorganic acid and more preferably a mineral acid from the viewpoint of efficiently adjusting the pH and efficiently fusing the aggregated particles.
Examples of the mineral acid include hydrochloric acid, sulfuric acid, nitric acid and the like, hydrochloric acid and sulfuric acid are preferable, and sulfuric acid is more preferable.
When using an acid, it is preferably used as an aqueous solution, and the concentration is preferably 0.1 to 5.0 N, and more preferably 0.5 to 3.0 N. Here, “N” represents the normality of the acid (the acid concentration mol / liter multiplied by the equivalent amount).
The addition amount of the surfactant is preferably 1 to 20 parts by weight with respect to 100 parts by weight of the total amount of the resin in the system from the viewpoint of suppressing the generation of coarse particles and reducing the remaining of the surfactant. Part by weight is more preferable, and 1.5 to 5 parts by weight is even more preferable.
Although there is no restriction | limiting in the temperature which adds surfactant and an acid, Preferably it is 10-60 degreeC, More preferably, it is 20-57 degreeC, More preferably, it is 25-57 degreeC, More preferably, it is 25-45 degreeC.
In this step, when an acid is added, the surfactant and the acid may be mixed and added, or may be added separately. When they are added separately, any of them may be added first, but from the viewpoint of suppressing the generation of coarse particles, it is preferable to add an acid after adding a surfactant.
In this step, when an acid is added, the pH of the resulting dispersion is lowered due to the addition of the acid, but the fusion property of the resin particles and the stability of the aggregated particles, that is, the fusion between the aggregated particles. From the viewpoint of preventing adhesion, it is preferable to add an acid such that the pH of the dispersion is 2.0 to 6.4, more preferably 4.0 to 6.0, and 4.5 to 5.5. More preferably, an acid is added.

Next, the temperature of the system containing the agglomerated particles (2) is maintained at a temperature of 10 ° C. or lower than the glass transition point of the graft polymer so that the agglomerated particles (2) mainly physically adhere to each other. The respective particles that were in a state of being fused are united to form core-shell particles.
If the pH of the dispersion is not 2.0 to 6.4 before adjusting the temperature of the system containing the agglomerated particles (2) to a temperature of 10 ° C. or lower than the glass transition point of the graft polymer, The pH may be 2.0 to 6.4 at temperature, and an acid may be added to bring the pH into this range.

From the viewpoint of fusing property and toner productivity, in this step, the temperature is at least 10 ° C. lower than the glass transition point of the graft polymer, preferably at least 8 ° C., more preferably at least 5 ° C. In this step, the temperature is 12 ° C. or higher, preferably 10 ° C. higher than the glass transition point of the graft polymer, from the viewpoint of improving chargeability and suppressing toner scattering. It is more preferable to hold at a temperature not higher than the temperature, more preferably not higher than 8 ° C.
Further, from the viewpoint of storage stability and chargeability of the toner, in this step, it is more preferable that the temperature be maintained at a temperature not higher than the melting point of the crystalline polyester (a), preferably not higher than 3 ° C.
Further, from the viewpoint of fusing property, toner storage stability, charging property, and toner productivity, in this step, the temperature is 5 ° C. lower than the glass transition point of the resin particles (B) and is higher than the glass transition point. It is preferable to hold at a temperature not higher than 10 ° C.
Further, from the viewpoint of the chargeability of the toner, in this step, it is more preferable to maintain the temperature at a temperature lower than the melting point of the release agent, preferably at a temperature 5 ° C. lower than the melting point.
In this step, from the viewpoint of particle fusibility, the temperature is preferably 55 to 75 ° C, more preferably 60 to 72 ° C, and still more preferably 64 to 70 ° C.
The pH of the dispersion in this step is preferably 2.0 to 6.4, preferably 4.0 to 6.4 from the viewpoint of preventing the fusion of the resin particles and the stability of the aggregated particles, that is, preventing the fusion of the aggregated particles. 0 is more preferable, and 4.5 to 5.5 is still more preferable.
In this step, when an acid is added, it is preferable to add the acid so that the pH of the dispersion after adding the acid is 2.0 to 6.4, and 4.0 to 6.0 is preferable. More preferably, it is more preferable to add acid so that it may become 4.5-5.5.

The holding time in this step is preferably 1 to 24 hours, more preferably 1 to 18 hours, and further preferably 1 to 5 hours, from the viewpoints of particle fusing property, storage stability, chargeability and toner productivity. .
In this step, when an acid is added, it is preferably added within 3 hours after reaching the holding temperature, more preferably within 2 hours, and further within 1 hour. preferable.

In this step, it is preferable to confirm the progress of fusion by monitoring the circularity of the generated core-shell particles. Circularity is monitored by the method described in the examples. When the circularity reaches 0.955 or more, the cooling is performed and the fusion is stopped. The roundness of the finally obtained core-shell particles is 0.955 to 0.995, preferably 0.958 to 0.985, and preferably 0.960 to 0.85 from the viewpoints of scattering properties and cleaning properties of the obtained toner. 985 is more preferable, and 0.965 to 0.980 is even more preferable.
The degree of circularity of the fused core-shell particles is preferably 0.01 or more larger than the degree of circularity of the agglomerated particles (2) from the viewpoint of improving the heat-resistant storage stability of the toner and suppressing scattering. More preferably, it is more preferably 0.015 or more.
In this step, it is considered that by increasing the circularity by 0.01 or more, the encapsulation by the shell is improved, the heat resistant storage stability is improved, and the scattering is suppressed.
BET specific surface area by nitrogen adsorption method of fusing the core-shell particles, 1.0~5.0m ² / g from the viewpoints of charging property and storage stability of the toner obtained is preferably, 1.0~4.0m ² / g, more preferably, 1.0～3.5M more preferably ² / g, more preferably 1.5~2.5m ² / g.

From the viewpoint of improving the image quality of the toner, the volume-median particle size of the core-shell particles obtained in this step is preferably 2 to 10 μm, more preferably 2 to 8 μm, more preferably 2 to 7 μm, still more preferably 3 to 8 μm. More preferably, it is 4-6 micrometers.
The average particle size of the fused core-shell particles obtained in this step is preferably equal to or less than the average particle size of the aggregated particles (2). That is, in this step, it is preferable that the core shell particles do not aggregate and fuse.

[Post-processing process]
In the present invention, a post-treatment step may be performed after step (3), and it is preferable to obtain toner particles by isolating the core-shell particles.
Since the core-shell particles obtained in the step (3) are present in the aqueous medium, it is preferable to first perform solid-liquid separation. For solid-liquid separation, a suction filtration method or the like is preferably used.
Before the solid-liquid separation, the pH of the dispersion at 25 ° C. is preferably adjusted to 5.5 to 7.5, and a base is preferably added. The base is preferably an alkali metal hydroxide from the viewpoint of heat-resistant storage stability of the toner.
As the alkali metal hydroxide, potassium hydroxide and sodium hydroxide are preferable.
It is preferable to perform washing after the solid-liquid separation. When a nonionic surfactant is used in the production of the resin particles (A) and (B), it is preferable to remove the added nonionic surfactant, so that it is aqueous below the cloud point of the nonionic surfactant. Washing with a solution is preferred. The washing is preferably performed a plurality of times.
Next, although it is preferable to dry, the temperature at the time of drying is preferably set so that the temperature of the core-shell particle itself is 5 ° C. or more lower than the melting point of the crystalline polyester, and is set so as to be 10 ° C. or more lower. It is more preferable. As a drying method, it is preferable to use a vibration type fluidized drying method, a spray drying method, a freeze drying method, a flash jet method, or the like. The water content after drying is preferably adjusted to 1.5% by weight or less, more preferably 1.0% by weight or less, from the viewpoint of reducing the amount of toner scattered and charging properties.

[Electrophotographic toner]
(toner)
The toner particles obtained by drying or the like can be used as they are as the toner of the present invention, but it is preferable to use toner particles whose surface has been treated as described below as the toner for electrophotography.
The softening point of the obtained toner is preferably 60 to 140 ° C., more preferably 60 to 130 ° C., and still more preferably 60 to 120 ° C. from the viewpoint of low-temperature fixability of the toner. The glass transition point is preferably 30 to 80 ° C., more preferably 40 to 70 ° C. from the viewpoints of low-temperature fixability, durability, and storage stability.
The circularity of the toner is preferably 0.955 to 0.985, more preferably 0.955 to 0.980, and still more preferably 0.965 to 0, from the viewpoints of storage stability, scattering properties, and cleaning properties of the toner. .980. The circularity of the toner particles can be measured by the method described later. The circularity of the toner particles is a value obtained by a ratio of the circumference of the circle equal to the projected area / the circumference of the projected image. The more circular the particles are, the closer the circularity is to 1. .
The toner obtained by the method of the present invention has a core-shell structure, and amorphous polyester (b) is preferably contained in the shell part in an amount of 50 to 100% by weight, more preferably 70 to 100% by weight, and still more preferably 90 to 90%. Contains 100% by weight.
The volume median particle size of the toner is preferably 1 to 10 μm, more preferably 2 to 8 μm, still more preferably 3 to 7 μm, and still more preferably 4 to 6 μm, from the viewpoint of high image quality and productivity of the toner.
The CV value of the toner is preferably 30% or less, more preferably 27% or less, still more preferably 25% or less, and further preferably 22% or less, from the viewpoint of high image quality and productivity.

(External additive)
In the electrophotographic toner of the present invention, the toner particles can be used as the toner as they are, but it is preferable to use a toner obtained by adding a fluidizing agent or the like to the toner particle surface as an external additive.
Examples of the external additive include inorganic fine particles such as hydrophobic silica, titanium oxide fine particles, alumina fine particles, cerium oxide fine particles, and carbon black, and arbitrary fine particles such as polymer fine particles such as polycarbonate, polymethyl methacrylate, and silicone resin. Of these, hydrophobic silica is preferred.
When the surface treatment of the toner particles is performed using the external additive, the amount of the external additive added is preferably 1 to 5 parts by weight, more preferably 100 parts by weight of the toner particles before the treatment with the external additive. 1 to 3.5 parts by weight, more preferably 1 to 3 parts by weight.

  The electrophotographic toner of the present invention can be used as a one-component developer or a two-component developer mixed with a carrier.

  Each property value of polyester, resin particles, toner, etc. was measured and evaluated by the following method.

[Acid value of polyester]
It measured according to JIS K0070. However, the measurement solvent was chloroform.

[Resin softening point, endothermic maximum peak temperature, melting point and glass transition point]
(1) Softening point Using a flow tester (manufactured by Shimadzu Corporation, trade name: CFT-500D), a load of 1.96 MPa was applied by a plunger while heating a 1 g sample at a heating rate of 6 ° C / min. And extruded from a nozzle with a diameter of 1 mm and a length of 1 mm. The amount of flow tester drop by the flow tester was plotted against the temperature, and the temperature at which half the sample flowed out was taken as the softening point.
(2) Endothermic maximum peak temperature, melting point and glass transition point Using a differential scanning calorimeter (manufactured by PerkinElmer, trade name: Pyris 6 DSC), the temperature is raised to 200 ° C., and the temperature lowering rate is 50 ° C./min. The sample cooled to 0 ° C. was measured at a heating rate of 10 ° C./min. Of the endothermic peaks observed, the peak temperature having the maximum peak area was defined as the maximum endothermic peak temperature. In the case of crystalline polyester, the peak temperature was taken as the melting point. In the case of an amorphous polyester, when an endothermic peak is observed, the temperature of the peak is measured, and when a step is observed without a peak being observed, the tangent indicating the maximum slope of the curve of the step and the step The glass transition point was defined as the temperature at the intersection with the base line extension line on the high temperature side.

[Glass Transition Point of Resin Particle (B) Containing Graft Polymer]
When measuring the glass transition point of the resin particles (B), the solvent was removed from the dispersion of resin particles (B) by lyophilization, and the obtained solid was measured by the above method.
The lyophilization of the resin particle (B) dispersion is performed using a freeze dryer (manufactured by Tokyo Rika Kikai Co., Ltd., trade names: FDU-2100 and DRC-1000), and 30 g of the resin particle (B) dispersion is -25. Vacuum drying was performed at 1 ° C. for 1 hour, −10 ° C. for 10 hours, and 25 ° C. for 4 hours, and the water content was dried to 1% by weight or less. The moisture content was determined by using an infrared moisture meter (trade name: FD-230, manufactured by Kett Scientific Laboratory), drying 5 g of the sample at a drying temperature of 150 ° C. and a measurement mode 96 (monitoring time 2.5 minutes). / Fluctuation range 0.05%).
The method for measuring the glass transition point was the same as the method for measuring the glass transition point of the resin.

[Number average molecular weight of resin and graft polymer]
The molecular weight distribution was measured by gel permeation chromatography and the number average molecular weight was calculated by the following method.
(1) Preparation of sample solution Polyester was dissolved in chloroform so that the concentration was 0.5 g / 100 ml. Subsequently, this solution was filtered using a fluororesin filter having a pore size of 2 μm (manufactured by Sumitomo Electric Industries, Ltd., trade name: FP-200) to remove insoluble components to obtain a sample solution.
(2) Molecular weight distribution measurement Chloroform was allowed to flow as a lysis solution at a flow rate of 1 ml / min, and the column was stabilized in a constant temperature bath at 40 ° C. 200 μl of the sample solution was injected there for measurement. The molecular weight of the sample was calculated based on a calibration curve prepared in advance. In the calibration curve at this time, several types of monodisperse polystyrene (monodisperse polystyrene manufactured by Tosoh Corporation); molecular weights 1.11 × 10 ⁶ , 3.97 × 10 ⁵ , 1.89 × 10 ⁵ , 9.89 × 10 ⁴ , 1.71 × 10 ⁴ , 9.49 × 10 ³ , 5.87 × 10 ³ , 1.01 × 10 ³ , 5.00 × 10 ² ) were used as standard samples.
Measuring apparatus: HPLC LC-9130NEXT (trade name, manufactured by Nippon Analytical Industries, Ltd.)
Analytical column: JAIGEL-2.5-HA + JAIGEL-MH-A (both trade names, manufactured by Nippon Analytical Industries, Ltd.)

[Volume Median Particle Size (D ₅₀ ) and Particle Size Distribution of Resin Particles, Release Agent Particles]
(1) Measuring device: Laser diffraction particle size measuring machine (Horiba, Ltd., trade name: LA-920)
(2) Measurement conditions: Distilled water was added to the measurement cell, and the volume-median particle size (D ₅₀ ) was measured at a temperature at which the absorbance falls within an appropriate range. The CV value was calculated according to the following formula.
CV value (%) = (standard deviation of particle size distribution / volume average particle size) × 100

[Solid content concentration of resin particle dispersion]
Using an infrared moisture meter (FD-230), 5 g of the resin particle dispersion was measured at a drying temperature of 150 ° C. in a measurement mode 96 (monitoring time 2.5 minutes / variation width 0.05%). The solid content concentration was calculated according to the following formula.
Solid content concentration (% by weight) = 100-M
M: moisture (%) = [(W−W ₀ ) / W] × 100
W: Sample weight before measurement (initial sample weight)
W ₀ : Sample weight after measurement (absolute dry weight)

[Volume Median Particle Size (D ₅₀ ) and Particle Size Distribution of Toner (Particles) and Aggregated Particles]
The volume median particle size of the toner (particles) was measured as follows.
-Measuring machine: Coulter Multisizer III (trade name, manufactured by Beckman Coulter)
・ Aperture diameter: 50μm
-Analysis software: Multisizer III version 3.51 (trade name, manufactured by Beckman Coulter)
・ Electrolyte: Isoton II (trade name, manufactured by Beckman Coulter)
Dispersion: Polyoxyethylene lauryl ether (trade name, Emulgen 109P, HLB: 13.6, manufactured by Kao Corporation) was dissolved in the electrolytic solution to obtain a dispersion having a concentration of 5% by weight.
-Dispersion condition: 10 mg of a toner measurement sample is added to 5 mL of the dispersion, and dispersed for 1 minute with an ultrasonic disperser, and then 25 mL of electrolyte is added, and further dispersed for 1 minute with an ultrasonic disperser. A sample dispersion was prepared.
Measurement conditions: The sample dispersion is added to 100 mL of the electrolytic solution to adjust the particle size of 30,000 particles to a concentration that can be measured in 20 seconds, and then 30,000 particles are measured and the particle size distribution thereof. From this, the volume median particle size (D ₅₀ ) was determined.
The CV value (%) was calculated according to the following formula.
CV value (%) = (standard deviation of particle size distribution / volume average particle size) × 100
The volume-median particle size of the agglomerated particles and the agglomerated particles (2) are the same when the agglomerated particle dispersion and the agglomerated particles (2) are used as the sample dispersion in the measurement of the volume-median particle size of the toner (particles). Measured.

[Core shell particle, toner circularity]
-Preparation of dispersion: The dispersion of core-shell particles was prepared by diluting with deionized water so that the solid content concentration of the core-shell particles was 0.001 to 0.05%. The toner dispersion was prepared by adding 50 mg of toner to 5 ml of 5% by weight polyoxyethylene lauryl ether (Emulgen 109P) aqueous solution, dispersing for 1 minute with an ultrasonic disperser, adding 20 ml of distilled water, It was prepared by dispersing for 1 minute with a sonic disperser.
Measurement device: Flow-type particle image analyzer (manufactured by Sysmex Corporation, trade name: FPIA-3000)
・ Measurement mode: HPF measurement mode

[BET specific surface area of toner particles]
A BET specific surface area was measured under the following conditions using Micromeritics FlowSorbIII (trade name, manufactured by Shimadzu Corporation).
Toner sample amount: 0.09 to 0.11 g
・ Deaeration condition: 40 ° C., 10 minutes ・ Adsorption gas: Nitrogen gas

[Evaluation of low-temperature fixability of toner]
Using a commercially available printer (trade name: Microline 5400, manufactured by Fuji Xerox Co., Ltd., J paper A4 size), the toner adhesion amount on the paper is 0.42 to 0.48 mg. A solid image of / cm ² was output without being fixed at a length of 50 mm, leaving a margin of 5 mm from the top edge of the A4 paper.
Next, the same printer with a variable temperature fixing device was prepared. The temperature of the fixing device was set to 100 ° C., and fixing was performed at a speed of 1.5 seconds per sheet in the A4 longitudinal direction to obtain a printed matter.
In the same manner, the temperature of the fixing device was increased by 5 ° C., and the fixing was performed to obtain a printed matter.
A 500 g weight is applied to the margin at the top of the printed image, after lightly pasting a piece of mending tape (product name: Scotch mending tape 810, width 18 mm) cut to a length of 50 mm. It was loaded and pressed once and again at a speed of 10 mm / sec. Thereafter, the affixed tape was peeled off from the lower end side at a peeling angle of 180 degrees and a speed of 10 mm / second to obtain a printed matter after the tape was peeled off. 30 sheets of high quality paper (Oki Data Co., Ltd., Excellent White Paper A4 size) is placed under the printed material before and after the tape is applied, and the reflected image density of the fixed image portion before and after the tape is applied to each printed material. , Measured using a colorimeter (GretagMacbeth, trade name: SpectroEye, light emission condition: standard light source D ₅₀ , observation field of view 2 °, density standard DINNB, absolute white standard) Calculated.
Fixing rate = (reflected image density after peeling tape / reflected image density before applying tape) × 100
The temperature at which the fixing rate was 90% or more was defined as the minimum fixing temperature. The lower the minimum fixing temperature, the better the low-temperature fixing property.

[Evaluation of heat-resistant storage stability of toner]
20 g of toner was put in a wide-mouthed polybin with an internal volume of 100 ml, sealed, and allowed to stand for 24 hours at an environment of 50 ° C. Thereafter, it was allowed to stand for 12 hours or more while being sealed at a temperature of 25 ° C. and cooled. Next, a sieve having a mesh size of 250 μm is set on a powder tester (trade name, manufactured by Hosokawa Micron Co., Ltd.), and 20 g of the toner is placed on the shaker for 30 seconds. The remaining toner weight on the sieve is measured. It was measured. The smaller the value, the better the heat resistant storage stability of the toner.

[Evaluation of chargeability of toner at normal temperature and normal humidity (under NN environment)]
At 50 ° C. and 50% relative humidity, 2.1 g of toner and 27.9 g of a silicone ferrite carrier (manufactured by Kanto Denka Kogyo Co., Ltd., average particle size: 40 μm) and a 50 cc cylindrical polypropylene bottle (Nikko Corporation) ) And shaken 10 times vertically and horizontally, and then mixed for 1 hour at a speed of 90 r / min using a tumbler mixer. The charge amount at that time was measured using a q / m meter (manufactured by EPPING). The higher the absolute value of the charge amount, the better the chargeability.
Measurement equipment, settings, etc. are as follows.
Measuring instrument: q / m-meter manufactured by EPPING
Setting: Mesh size: 635 mesh (aperture: 24 μm, made of stainless steel)
Soft blow, blow pressure (1000V)
Suction time: 90 seconds Charge amount (μC / g) = Total amount of electricity after 90 seconds (μC) / Amount of toner sucked (g)

[Evaluation of chargeability of toner at high temperature and high humidity (HH environment)]
The toner after chargeability evaluation at room temperature and normal humidity was placed at an air temperature of 30 ° C. and a relative humidity of 85% (high temperature and high humidity environment) and held for 12 hours. Thereafter, the mixture was placed in a high temperature and high humidity environment at an air temperature of 25 ° C. and a relative humidity of 50%, stirred for 1 minute with a ball mill, and then charged in the same manner as the chargeability evaluation at room temperature and normal humidity. The higher the absolute value of the charge amount, the better the chargeability.

[Production of polyester]
Production Example 1
(Production of crystalline polyester X1)
The inside of a four-necked flask equipped with a nitrogen introduction tube, a dehydration tube, a stirrer, and a thermocouple was purged with nitrogen, and 3936 g of 1,9-nonanediol and 4848 g of sebacic acid were added. While stirring, the temperature was raised to 140 ° C., maintained at 140 ° C. for 3 hours, and then heated from 140 ° C. to 200 ° C. over 10 hours. Thereafter, 50 g of di (2-ethylhexanoic acid) tin was added, and the mixture was further maintained at 200 ° C. for 1 hour. Then, the pressure in the flask was lowered and maintained at 8.3 kPa for 4 hours to obtain crystalline polyester X1. . Table 1 shows the softening point, melting point, crystallinity index, number average molecular weight, and acid value of the obtained crystalline polyester X1.

Production Example 2
(Production of crystalline polyester X2)
The inside of a four-necked flask equipped with a nitrogen introduction tube, a dehydration tube, a stirrer, and a thermocouple was purged with nitrogen, and 2419 g of 1,6-hexanediol and 4957 g of 1,12-dodecanedioic acid were added. While stirring, the temperature was raised to 140 ° C., maintained at 140 ° C. for 3 hours, and then heated from 140 ° C. to 200 ° C. over 10 hours. Thereafter, 30 g of di (2-ethylhexanoic acid) tin was added, and the mixture was further maintained at 200 ° C. for 1 hour. Then, the pressure in the flask was lowered and maintained at 8.3 kPa for 3 hours to obtain crystalline polyester X2. . Table 1 shows the softening point, melting point, crystallinity index, number average molecular weight, and acid value of the obtained crystalline polyester X2.

Production Example 3
(Production of amorphous polyester Y1)
The inside of a four-necked flask equipped with a nitrogen introduction tube, a dehydration tube, a stirrer, and a thermocouple was replaced with nitrogen, and 3528 g of polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, Put 1404 g of polyoxyethylene (2.0) -2,2-bis (4-hydroxyphenyl) propane, 1248 g of terephthalic acid, 1541 g of dodecenyl succinic anhydride, and 40 g of di (2-ethylhexanoic acid) tin under a nitrogen atmosphere. While stirring, the temperature was raised to 230 ° C. and maintained at 230 ° C. for 6 hours, and then the pressure in the flask was further lowered and maintained at 8.3 kPa for 1 hour. Then, after cooling to 215 ° C. and returning to atmospheric pressure, 300 g of trimellitic anhydride was added and maintained at 215 ° C. for 1 hour, then the pressure in the flask was further lowered and maintained at 8.3 kPa for 3 hours. As a result, amorphous polyester Y1 was obtained. Table 1 shows the softening point, glass transition point, crystallinity index, number average molecular weight, and acid value of the obtained amorphous polyester Y1.

Production Example 4
(Production of amorphous polyester Y2)
The inside of a four-necked flask equipped with a nitrogen introduction tube, a dehydration tube, a stirrer, and a thermocouple was replaced with nitrogen, and 3322 g of polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, Polyoxyethylene (2.0) -2,2-bis (4-hydroxyphenyl) propane (31 g), terephthalic acid (662 g) and di (2-ethylhexanoic acid) tin (25 g) were added and stirred at 230 ° C. in a nitrogen atmosphere. Then, the pressure in the flask was further lowered and maintained at 8.0 kPa for 1 hour. After returning to atmospheric pressure, the mixture was cooled to 190 ° C., 685 g of fumaric acid and 2.4 g of tert-butylcatechol (polymerization inhibitor) were added, and maintained at a temperature of 190 ° C. for 1 hour, followed by 210 ° C. over 2 hours. The temperature was raised to. Further, the pressure in the flask was lowered and maintained at 8.0 kPa for 4 hours to obtain amorphous polyester Y2. Table 1 shows the softening point, glass transition point, crystallinity index, number average molecular weight, and acid value of the obtained amorphous polyester Y2.

Production Example 5
(Production of amorphous polyester Y3)
The inside of a four-necked flask equipped with a nitrogen introduction tube, a dehydration tube, a stirrer, and a thermocouple was replaced with nitrogen, and 1750 g of polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, Put 1625 g of polyoxyethylene (2.0) -2,2-bis (4-hydroxyphenyl) propane, 1145 g of terephthalic acid, 161 g of dodecenyl succinic anhydride, and 25 g of di (2-ethylhexanoic acid) tin under a nitrogen atmosphere. While stirring, the temperature was raised to 230 ° C. and maintained at 230 ° C. for 5 hours, and then the pressure in the flask was further lowered and maintained at 8.0 kPa for 1 hour. After returning to atmospheric pressure, it was cooled to 220 ° C. and 480 g of trimellitic anhydride was added. Then, after confirming that the softening point measured according to ASTM D36-86 reached 120 ° C., the reaction was stopped by lowering the temperature to obtain amorphous polyester Y3. Table 1 shows the softening point, glass transition point, crystallinity index, number average molecular weight, and acid value of the obtained amorphous polyester Y3.

[Production of graft polymer]
Production Examples 6 to 11 and 14
(Production of graft polymers A to F and I)
A polyester raw material monomer and catalyst other than fumaric acid described in Table 2 were put into a four-necked flask equipped with a nitrogen introduction tube, a dehydration tube, a stirrer, and a thermocouple, and maintained at 235 ° C. for 10 hours in a nitrogen atmosphere. Thereafter, the temperature was further maintained at 235 ° C. and 8.0 kPa for 1 hour. After cooling to 160 ° C., a mixture of acrylic acid, addition polymerization monomer and dibutyl peroxide (polymerization initiator) described in Table 2 was added dropwise over 1 hour using a dropping funnel. After dripping, it hold | maintained at 160 degreeC for 1 hour. Thereafter, the temperature was raised to 180 ° C., fumaric acid and tert-butylcatechol (polymerization inhibitor) were added, the temperature was raised from 180 ° C. to 210 ° C. at 10 ° C./hour, and held at 210 ° C. for 1 hour. The reaction was stopped by lowering the temperature after confirming that the softening point measured according to ASTM D36-86 reached the desired temperature shown in Table 2 while maintaining at 10 kPa at 10 ° C. to obtain graft polymers A to F and I It was. Table 2 shows the softening point, glass transition point, number average molecular weight, and acid value of the obtained graft polymers A to F and I.

Production Example 12
(Production of graft polymer G)
Polyester raw material monomers and catalysts other than fumaric acid and trimellitic anhydride described in Table 2 were placed in a four-necked flask equipped with a nitrogen introduction tube, a dehydration tube, a stirrer, and a thermocouple, and 235 ° C. under a nitrogen atmosphere. At 235 ° C. and 8.0 kPa for 1 hour. After cooling to 160 ° C., a mixture of acrylic acid, addition polymerization monomer and dibutyl peroxide (polymerization initiator) described in Table 2 was added dropwise over 1 hour using a dropping funnel. After dripping, it hold | maintained at 160 degreeC for 1 hour. Thereafter, the temperature was raised to 180 ° C., fumaric acid, trimellitic anhydride and tert-butylcatechol (polymerization inhibitor) were added, and the temperature was raised from 180 ° C. to 210 ° C. at 10 ° C./hour. Holding for 210 hours, holding at 210 ° C. and 10 kPa, and confirming that the softening point measured according to ASTM D36-86 reached 135 ° C., the reaction was stopped by lowering the temperature to obtain graft polymer G. Table 2 shows the softening point, glass transition point, number average molecular weight, and acid value of the obtained graft polymer G.

Production Example 13
(Production of graft polymer H)
After putting the polyester raw material monomer and catalyst other than fumaric acid described in Table 2 into a four-necked flask equipped with a nitrogen introduction tube, a dehydration tube, a stirrer, and a thermocouple, the temperature was raised to 160 ° C. in a nitrogen atmosphere. The mixture of acrylic acid, addition polymerization monomer and dibutyl peroxide (polymerization initiator) described in Table 2 was added dropwise with a dropping funnel over 1 hour. After dripping, it hold | maintained at 160 degreeC for 1 hour. Then, it maintained at 235 degreeC for 10 hours, and also maintained at 235 degreeC and 8.0 kPa for 1 hour. Cool to 180 ° C., add fumaric acid and tert-butylcatechol (polymerization inhibitor), heat from 180 ° C. to 210 ° C. at 10 ° C./hour, hold at 210 ° C. for 1 hour, 210 ° C., 10 kPa Then, after confirming that the softening point measured according to ASTM D36-86 reached 110 ° C., the reaction was stopped by lowering the temperature to obtain graft polymer H. Table 2 shows the softening point, glass transition point, number average molecular weight, and acid value of the obtained graft polymer H.

[Production of resin particles and release agent particles]
Production Example 15
(Preparation of resin particle dispersion (A-1))
In a flask equipped with a stirrer, 90 g of crystalline polyester X1, 510 g of amorphous polyester Y1, copper phthalocyanine pigment (trade name: ECB301, manufactured by Dainichi Seika Kogyo Co., Ltd.), polyoxyethylene alkyl ether (nonionic) Surfactant, trade name: Emulgen 150, manufactured by Kao Corporation) 8.5 g, 15 wt% sodium dodecylbenzenesulfonate aqueous solution (anionic surfactant, trade name: Neoperex G-15, manufactured by Kao Corporation) ) 80 g, 225 g of a 5 wt% potassium hydroxide aqueous solution was added, and the mixture was heated to 98 ° C. with melting and melted, and mixed at 98 ° C. for 2 hours to obtain a resin mixture.
Next, 1118 g of deionized water was added dropwise at a rate of 6 g / min while stirring at 98 ° C. to obtain an emulsion. Next, the obtained emulsion was cooled to 25 ° C., and a resin particle dispersion (A-1) was obtained through a 200-mesh (mesh 105 μm) wire mesh. Table 3 shows the solid content concentration, volume median particle size, and CV value of the obtained resin particle dispersion.

Production Example 16
(Preparation of resin particle dispersion (A-2))
In a flask equipped with a stirrer, 90 g of crystalline polyester X2, 510 g of amorphous polyester Y1, 45 g of copper phthalocyanine pigment (ECB301), 8.5 g of polyoxyethylene alkyl ether (Emulgen 150), 15% by weight sodium dodecylbenzenesulfonate An aqueous solution (Neopelex G-15) 80 g, a 5 wt% potassium hydroxide aqueous solution 232 g were added, and the mixture was heated to 98 ° C. with stirring and melted, and mixed at 98 ° C. for 2 hours to obtain a resin mixture.
Next, 1111 g of deionized water was added dropwise at a rate of 6 g / min while stirring to obtain an emulsion. Next, the obtained emulsion was cooled to 25 ° C., and a resin particle dispersion (A-2) was obtained through a 200-mesh (mesh 105 μm) wire mesh. Table 3 shows the solid content concentration, volume median particle size, and CV value of the obtained resin particle dispersion.

Production Example 17
(Preparation of resin particle dispersion (A-3))
In Production Example 15, resin particle dispersion (A-3) was prepared in the same manner as in Production Example 15 except that 90 g of crystalline polyester X1 and 510 g of amorphous polyester Y1 were changed to 180 g of crystalline polyester X and 420 g of amorphous polyester Y1. ) Table 3 shows the solid content concentration, volume median particle size, and CV value of the obtained resin particle dispersion.

Production Example 18
(Preparation of resin particle dispersion (A-4))
Resin in the same manner as in Production Example 15, except that 90 g of crystalline polyester X1 and 510 g of amorphous polyester Y1 were changed to 90 g of crystalline polyester X1, 300 g of amorphous polyester Y2 and 210 g of amorphous polyester Y3 in Production Example 15. A particle dispersion (A-4) was obtained. Table 3 shows the solid content concentration, volume median particle size, and CV value of the obtained resin particle dispersion.

Production Examples 19 to 27 and 32
(Preparation of resin particle dispersions (B-1) to (B-9) and (B-14))
Into a 5 L flask equipped with a stirrer, reflux condenser, dropping funnel, thermometer and nitrogen introduction tube was charged 400 g of methyl ethyl ketone, and 200 g of the graft polymer shown in Table 4 (resin particle dispersion (B-9 of Production Example 27)) ) Was added and dissolved in 100 g each of two types of graft polymers at room temperature. The resulting solution was neutralized by adding 45 g of 5% by weight aqueous sodium hydroxide, followed by addition of 750 g of deionized water, and then the pressure was reduced and maintained at 40 kPa with stirring, at a temperature of 60 ° C. The methyl ethyl ketone was distilled off to obtain an emulsion. The obtained emulsion was cooled to 25 ° C., passed through a 200-mesh wire mesh, deionized water was added to prepare a solid content of 23.5% by weight, and resin particle dispersions (B-1) to (B- 9) and (B-14) were obtained. Table 4 shows the volume-median particle size, CV value, and glass transition point of each of the obtained resin particle dispersions (B-1) to (B-9) and (B-14).

Production Example 28
(Preparation of resin particle dispersion (B-10))
In a flask equipped with a stirrer, 600 g of graft polymer C, polyoxyethylene alkyl ether (nonionic surfactant, trade name: Emulgen 430, manufactured by Kao Corp.), 6.0 g, 15% by weight sodium dodecylbenzenesulfonate 80 g of an aqueous solution (anionic surfactant, trade name: Neoperex G-15, manufactured by Kao Corporation), 228 g of a 5 wt% aqueous potassium hydroxide solution was added, and the mixture was heated to 98 ° C. with stirring and melted. The mixture was mixed at 98 ° C. for 2 hours to obtain a resin mixture.
Next, 1115 g of deionized water was added dropwise at a rate of 6 g / min while stirring to obtain an emulsion. Next, the obtained emulsion is cooled to 25 ° C., and deionized water is added through a 200 mesh (mesh 105 μm) wire mesh to prepare a solid content of 23.5% by weight. -10) was obtained. Table 4 shows the volume-median particle size, CV value, and glass transition point of the obtained resin particle dispersion.

Production Examples 29-31
(Preparation of resin particle dispersions (B-11) to (B-13))
In Production Example 19, except that 200 g of the graft polymer was changed to 200 g of amorphous polyester shown in Table 4 (the resin particle dispersion (B-13) of Production Example 31 was 100 g of two types of amorphous polyester), Resin particle dispersions (B-11) to (B-13) were obtained in the same manner as in Production Example 19. Table 4 shows the volume-median particle size, CV value, and glass transition point of the obtained resin particle dispersion.

Production Example 33
(Production of release agent particle dispersion)
2. In a 1 liter beaker, sodium acrylate-sodium maleate copolymer aqueous solution (trade name: Poise 521, effective concentration 40% by weight, manufactured by Kao Corporation) as a sodium polycarboxylate aqueous solution in 200 g of deionized water After 8 g was dissolved, 5 g of carnauba wax (manufactured by Hiroyuki Kato, product name: carnauba wax No. 1, melting point 83 ° C.) and paraffin wax (manufactured by Nippon Seiki Co., Ltd., product name: HNP) −9, melting point 75 ° C.) 45 g was added, and the mixture was melted while maintaining the temperature at 90 to 95 ° C. to obtain a molten mixture in which carnauba wax and paraffin wax were melted together.
The aqueous solution containing the obtained molten mixture was further subjected to a dispersion treatment for 30 minutes with an ultrasonic homogenizer (manufactured by Nippon Seiki Co., Ltd., trade name: US-600T) while maintaining the temperature at 90 to 95 ° C. Then, ion-exchanged water was added thereto to adjust the release agent solid content to 20% by weight to obtain a release agent particle dispersion. The volume median particle size (D ₅₀ ) of the release agent particles in the release agent particle dispersion was 450 nm, and the CV value was 30%.

[Production of surfactant]
Production Example 34
(Synthesis of Surfactant 1 (Polyoxyethylene (13) Distyrenated Phenyl Ether Monosulfate Ammonium Salt))
608 g (2 mol) of distyrenated phenol (manufactured by Kawaguchi Chemical Industry Co., Ltd.) and 0.56 g (0.01 mol) of potassium hydroxide were charged into an autoclave equipped with a stirrer, a temperature controller and an ethylene oxide introduction device. Water was removed at 30 ° C. and 1.3 kPa for 30 minutes. Thereafter, nitrogen substitution was carried out, and after raising the temperature to 145 ° C., 1144 g (26 mol) of ethylene oxide was charged. The addition reaction was carried out at 145 ° C. until the pressure became constant, and aging was carried out at 145 ° C. for 1 hour, followed by cooling to 80 ° C. Next, an inorganic alkali adsorbent was added, and potassium hydroxide was removed by filtration to obtain polyoxyethylene (13) distyrenated phenol having an average addition mole number of ethylene oxide of 13 moles (however, The numbers in parentheses indicate the average number of moles of ethylene oxide added, and so on.
438.0 g (0.5 mol) of this polyoxyethylene (13) distyrenated phenol was charged into a reactor equipped with a stirrer and a temperature controller, and water was removed at 110 ° C. and 1.3 kPa for 30 minutes. . After cooling to 80 ° C., 46.1 g (0.475 mol) of sulfamic acid was charged, the temperature was raised to 110 ° C., the mixture was reacted for 3 hours, and polyoxyethylene (13) distyrenated phenyl ether monosulfate ammonium salt (surface activity Agent 1) was obtained.

[Production of toner]
Example 1
(Preparation of Toner A)
<Step (1): Production of Aggregated Particle (1)>
250 g of resin particle dispersion (A-1), 64.8 g of deionized water, and 42 g of release agent particle dispersion are placed in a four-necked flask with an internal volume of 5 liters equipped with a dehydrating tube, a stirrer, and a thermocouple. Mixed at 25 ° C. Next, while stirring the mixture, an aqueous solution in which 23 g of ammonium sulfate was dissolved in 194 g of deionized water was added dropwise at 25 ° C. over 5 minutes, and then the temperature was raised to 60 ° C. so that the volume-median particle size of the aggregated particles was 4 It was kept at 60 ° C. until it became 5 μm to obtain agglomerated particles (1).
<Step (2): Production of Aggregated Particle (2)>
33 g of deionized water was added to the dispersion (total amount) of the aggregated particles (1) obtained in step (1), and the temperature of the dispersion of aggregated particles (1) was cooled to 55 ° C. The pH at this time was 5.7. A 20% by weight aqueous potassium hydroxide solution was added thereto to adjust the pH to 7.1. Next, while the temperature of the 55 ° C. dispersion was raised at a rate of 0.8 ° C./hour, 157.1 g of the resin particle dispersion (B-1) was added dropwise at a rate of 0.5 ml / minute to obtain the aggregated particles (2). A dispersion was obtained. Table 5 shows the volume-median particle size, circularity, and pH of the dispersion of the obtained aggregated particles (2). Moreover, the temperature of the dispersion liquid after completion | finish of dripping was 59 degreeC.
<Process (3): Fusion process of aggregated particles (2)>
To the dispersion (total amount) of the aggregated particles (2) obtained in the step (2), 3.4 g of polyoxyethylene (13) distyrenated phenyl ether monosulfate ammonium salt (surfactant 1) and 3782 g of deionized water. A mixed aqueous solution was added. Thereafter, 2.0 N sulfuric acid was added so that the pH at 25 ° C. was 5.2.
The dispersion liquid of the aggregated particles (2) adjusted in pH was heated to 68 ° C. and held at 68 ° C. for 2 hours, and the particles were fused to obtain core-shell particles.
<Washing / Drying / External Addition Process>
The core-shell particle dispersion obtained in step (3) was cooled to 55 ° C., and a 5.0 wt% aqueous potassium hydroxide solution was added so that the pH at 25 ° C. was 6.0. Thereafter, the dispersion of core-shell particles was held at 55 ° C. with stirring for 1 hour.
Next, the dispersion was cooled to 25 ° C., and the solid content was separated by suction filtration while being kept at 25 ° C., washed with deionized water, and dried at 33 ° C. to obtain toner particles. Table 5 shows the circularity, BET specific surface area, and volume-median particle size of the obtained toner. 100 parts by weight of the toner particles, 2.5 parts by weight of hydrophobic silica (trade name: RY50, manufactured by Nippon Aerosil Co., Ltd., average particle size: 0.04 μm), and hydrophobic silica (trade name: Cabo Seal TS720, Cabot Corporation) Manufactured, average particle size; 0.012 μm) was put in a Henschel mixer, stirred, and passed through a 150-mesh sieve to obtain toner A. Table 5 shows the evaluation of the obtained toner.

Examples 2, 12 and 13
(Production of toners B, L, and M)
As shown in Table 5, the resin particle dispersion (A-1) in step (1) was changed to resin particle dispersions (A-2) to (A-4) in the same manner as in Example 1. A toner was prepared. Table 5 shows the evaluation of the obtained toner.

Examples 3 to 10 and Comparative Examples 1 to 3
(Production of toners C to J and N to P)
As shown in Table 5, resin particle dispersions (B-2) to (B-9) and (B-11) to (B-13) of the resin particle dispersion (B-1) in the step (2) are shown in Table 5. A toner was prepared in the same manner as in Example 1 except that the above was changed. Table 5 shows the evaluation of the obtained toner.

Example 11
(Preparation of toner K)
A toner was prepared in the same manner as in Example 1 except that the step (2) was changed as follows. Table 5 shows the evaluation of the obtained toner.
<Step (2): Production of Aggregated Particle (2)>
33 g of deionized water was added to the dispersion (total amount) of the aggregated particles (1) obtained in step (1), and the temperature of the aggregated particles (1) dispersion was cooled to 55 ° C. The pH at this time was 5.7. Next, while the temperature of the 55 ° C. dispersion was raised at a rate of 0.8 ° C. per hour, 157.1 g of the resin particle dispersion (B-10) was added dropwise at a rate of 0.5 ml per minute to obtain aggregated particles (2). A dispersion was obtained. Table 5 shows the volume-median particle size, circularity, and pH of the dispersion of the obtained aggregated particles (2). Moreover, the temperature of the dispersion liquid after completion | finish of dripping was 59 degreeC.

Comparative Example 4
(Production of Toner Q)
A toner was prepared in the same manner as in Example 1 except that the resin particle dispersion (B-1) in the step (2) was changed to a resin particle dispersion (B-14) as shown in Table 5. Table 5 shows the evaluation of the obtained toner. Of the toner evaluations, regarding the low-temperature fixability, filming on the developing blade occurred at the time of evaluation, and a printed matter that could be evaluated was not obtained.

  From Table 5, it can be seen that the electrophotographic toners of the examples are all excellent in low-temperature fixability, chargeability under high temperature and high humidity, and heat-resistant storage stability as compared with the electrophotographic toners of the comparative examples.

  The toner for electrophotography of the present invention is suitable for use as an electrophotographic toner used in electrophotography because it has both good low-temperature fixability and chargeability under high temperature and high humidity and excellent heat-resistant storage stability. it can. According to the method of the present invention, a toner having such characteristics can be produced efficiently.

Claims (14)

A core containing a crystalline polyester (a) which is a polycondensation product of an α, ω-alkanediol having 4 to 12 carbon atoms and an aliphatic dicarboxylic acid having 8 to 12 carbon atoms, and a release agent having a melting point of 60 to 90 ° C. And a core-shell type electrophotographic toner comprising a shell made of a graft polymer composed of a side chain segment (A1) made of a polyester resin and a main chain segment (A2) made of an addition polymerization resin. The weight ratio [(A1) / (A2)] of the segment (A1) and the main chain segment (A2) is 95/5 to 55/45, and the addition polymerization resin of the main chain segment (A2) is polystyrene or An electrophotographic toner which is a styrene-acrylic copolymer.   The electrophotographic toner according to claim 1, wherein the content of the structural unit derived from styrene in the main chain segment (A2) is 60 to 100% by weight. The toner for electrophotography according to claim 1 or 2 , wherein the crystalline polyester (a) has a melting point of 60 to 90 ° C. The toner for electrophotography according to any one of claims 1 to 3 , further comprising an amorphous polyester (b) in the core. An acid component in which the amorphous polyester (b) contains 20 to 50 mol% of an alkyl succinic acid having a branched alkyl group having 9 to 14 carbon atoms and / or an alkenyl succinic acid having an alkenyl group having 9 to 14 carbon atoms; The toner for electrophotography according to claim 4 , which is an amorphous polyester that is a polycondensation product with an alcohol component. The electrophotography according to claim 4 or 5 , wherein the weight ratio [(a) / (b)] of the crystalline polyester (a) and the amorphous polyester (b) in the core is 5/95 to 40/60. Toner. The toner for electrophotography according to any one of claims 1 to 6 , wherein the release agent comprises two or more release agents, and all of the release agents have a melting point of 60 to 90 ° C. The method for producing a core-shell type electrophotographic toner according to any one of claims 1 to 7 , comprising the following steps (1) to (3).
Step (1): Resin particles (A) containing crystalline polyester (a) obtained by polycondensation of α, ω-alkanediol having 4 to 12 carbon atoms and aliphatic dicarboxylic acid having 8 to 12 carbon atoms And a step of agglomerating release agent particles having a melting point of 60 to 90 ° C. to obtain aggregated particles (1) Step (2): The aggregated particles (1) obtained in Step (1) are made of a polyester resin. Step of adding aggregated particles (2) by adding resin particles (B) containing a graft polymer composed of side chain segments (A1) and main chain segments (A2) made of addition polymerization resin Step (3) : A step of obtaining core-shell particles by maintaining the temperature of the system containing the agglomerated particles (2) at a temperature of 10 ° C. lower than the glass transition point of the graft polymer and fusing them. The method for producing an electrophotographic toner according to claim 8, wherein the graft polymer is obtained by a method having the following steps (a-1) and (a-2).
Step (a-1): As addition polymerization monomer (a2), addition polymerization system having carboxy group by addition polymerization reaction from styrene or styrene and (meth) acrylic acid ester and vinyl monomer having carboxy group Obtaining resin
Step (a-2): Step of mixing and condensing the addition polymerization resin and the polyester resin (a1) The method for producing an electrophotographic toner according to claim 8 or 9, wherein the resin particles (A) contain a colorant. The method for producing a toner for electrophotography according to any one of claims 8 to 10, wherein the resin particles (B) are obtained by dissolving the graft polymer in an organic solvent and adding water to perform phase inversion emulsification. . After adjusting and / or adjusting the pH at 25 ° C. of the aqueous mixture containing the aggregated particles (2) and the surfactant (A) to 2.0 to 6.4, step (3) Maintaining the temperature system containing aggregated particles (2) to a temperature of 10 ° C. or higher temperature lower than the glass transition point of the graft polymer, by fusing, to give compound core-shell particles, according to claim 8-11 The method for producing an electrophotographic toner according to any one of the above. The electron according to any one of claims 8 to 12, wherein in step (2), the resin particles (B) are added after adjusting the pH of the system containing the aggregated particles (1) to 6.5 to 8.0. A method for producing a photographic toner. An acid component in which the resin particles (A) contain 20 to 50 mol% of an alkyl succinic acid having a branched alkyl group having 9 to 14 carbon atoms and / or an alkenyl succinic acid having an alkenyl group having 9 to 14 carbon atoms, and an alcohol The method for producing an electrophotographic toner according to any one of claims 8 to 13, comprising an amorphous polyester (b) obtained by condensation polymerization with a component.