JP2007286240A - Release agent for toner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a release agent for toners capable of satisfying both of excellent low-temperature fixability and durability, and a toner containing the release agent, which excels in both of low-temperature fixability and durability. <P>SOLUTION: The release agent for toners comprises a ketone compound containing a compound represented by formula (1) and having a free fatty acid content of ≤0.5 wt.%. The toner for electrophotography contains the release agent for toner and a binder resin. In the formula (1), R<SP>1</SP>and R<SP>2</SP>are each an aliphatic hydrocarbon group or an aromatic hydrocarbon group, provided that the total number of carbon atoms in R<SP>1</SP>and R<SP>2</SP>is 20-50. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a toner used in an electrophotographic method, an electrostatic recording method, an electrostatic printing method, and the like, and a release agent used for the toner.

In recent years, demand for on-demand printing has increased, and there has been a demand for toners with higher image quality, higher speed, and higher reliability. From the above viewpoint, toners having both fixing ability and durability are required. Has been.
Conventionally, there has been disclosed a toner obtained by melt kneading and pulverizing a toner material containing a binder resin, a colorant and a release agent for improving the fixing property. It has been proposed to use a ketone compound as a mold agent (see Patent Document 1 and Patent Document 2).
On the other hand, a toner having a small particle diameter is demanded for improving the image quality, and from this viewpoint, a toner obtained by a wet manufacturing method containing a ketone compound is disclosed (Patent Document 3).

Japanese Patent Laid-Open No. 10-232505 JP 2000-267347 A JP 2001-134005 A

However, if a release agent is added in order to improve the low-temperature fixability, the durability of the toner is deteriorated due to poor dispersion of the release agent. In particular, when a toner is produced by a wet method, the release agent has a low solubility and tends to be poorly dispersed. In particular, in the emulsion aggregation method, unlike the melt-kneading method, a mechanical share is not added in the manufacturing process, so that it is generally more difficult to uniformly disperse the release agent. If the dispersibility of the release agent is not uniform, not only the low-temperature fixability is impaired, but also the durability is poor, and as a result, image deterioration is likely to occur.
On the other hand, if measures such as increasing the molecular weight of the binder resin are taken to improve the durability, the low-temperature fixability is impaired. As described above, no toner has been developed that can improve both low-temperature fixability and durability at the same time.
An object of the present invention is to provide a toner release agent capable of achieving both excellent low-temperature fixability and durability, and a toner having both low-temperature fixability and durability, containing the release agent. .

（式中、Ｒ¹及びＲ²はそれぞれ脂肪族炭化水素基または芳香族炭化水素基であり、Ｒ¹とＲ²の合計炭素数が２０〜５０である。）
（２）上記（１）のトナー用離型剤及び結着樹脂を含有する電子写真用トナー、
に関する。 The present invention
(1) A toner release agent comprising a ketone compound containing a compound represented by the following general formula (1) and having a free fatty acid content of 0.5% by weight or less.

(In the formula, R ¹ and R ² are each an aliphatic hydrocarbon group or an aromatic hydrocarbon group, and the total carbon number of R ¹ and R ² is 20 to 50.)
(2) An electrophotographic toner containing the toner release agent and the binder resin according to (1) above,
About.

  According to the present invention, it is possible to provide a toner release agent for toner capable of achieving both excellent low-temperature fixability and durability, and a toner excellent in low-temperature fixability and durability containing the release agent. .

The toner release agent of the present invention comprises a specific ketone compound, and the free fatty acid content in the ketone compound is 0.5% by weight or less. By using the toner release agent of the present invention, it is possible to achieve both contradictory physical properties of excellent low-temperature fixability and durability.
That is, it is generally known that the presence of free fatty acids has an advantageous effect on low-temperature fixability, but has an adverse effect on durability. However, in the present invention, it has been surprisingly found that, by reducing the amount of free fatty acid in a specific ketone compound, it is possible to improve both the low-temperature fixability and the contradictory physical properties at the same time. The toner release agent of the present invention will be described below.

The toner release agent of the present invention comprises a ketone compound containing the compound represented by the general formula (1) and having a free fatty acid content of 0.5% by weight or less. In the present invention, the ketone compound is a compound containing a target product such as a ketone and a compound such as a fatty acid derived from a raw material accompanying the production.
In the general formula (1), R ¹ and R ² are each an aliphatic hydrocarbon group or an aromatic hydrocarbon group, and are preferably an aliphatic hydrocarbon group from the viewpoint of fixability. The total number of carbon atoms of R ¹ and R ² is 20 to 50, preferably 22 to 50, more preferably 22 to 48, from the viewpoints of storage stability, low-temperature fixability, and compatibility with the binder resin.

  Examples of the aliphatic hydrocarbon group include an alkyl group having 1 to 49 carbon atoms and an alkenyl group having 1 to 49 carbon atoms. For example, methyl group, ethyl group, propyl group, butyl group, pentyl group, hexyl group, heptyl Group, octyl group, nonyl group, decyl group, dodecyl group, hexadecyl group, heptadecyl group, octadecyl group, docosyl group, octacosyl group, hexatriacontyl group, hexatetracontyl group, butenyl group, pentenyl group, hexenyl group, Examples include octenyl group, nonenyl group, dodecenyl group, octadecenyl group, dococenyl group, octacocenyl group and the like.

  Examples of the aromatic hydrocarbon group include a phenyl group and an alkylphenyl group having an alkyl group having 1 to 43 carbon atoms. For example, a methylphenyl group, an ethylphenyl group, a propylphenyl group, a pentylphenyl group, a hexylphenyl group, Examples include heptylphenyl group, octylphenyl group, nonylphenyl group, decylphenyl group, octadecylphenyl group and the like.

Specific examples of the ketone compound represented by the general formula (1) include methyltricosyl ketone, pentyl octadecyl ketone, hexadecyl heptadecyl ketone, didecyl ketone, diundecyl ketone, didodecyl ketone, ditridecyl ketone, and ditetradecyl. Ketones, dipentadecyl ketones, dihexadecyl ketones, diheptadecyl ketones, dioctadecyl ketones, dinonane decyl ketones, dieicodyl ketones, diheneicosyl ketones, didocosyl ketones, ditricosyl ketones, ditetracosyl ketones, etc. It is done.
From the standpoint of crystallinity, each of R ¹ and R ² is preferably a linear alkyl group, and the linear alkyl group is preferably those having 11 to 24 carbon atoms, more preferably those having 12 to 24 carbon atoms, 22 is more preferable.

  The ketone compound is obtained by subjecting the carboxylic acid having an aliphatic hydrocarbon or aromatic hydrocarbon group to dry distillation at a high temperature, preferably a temperature of 340 to 350 ° C., and decarboxylation in the presence of a metal oxide catalyst. be able to. Here, examples of the metal oxide catalyst include magnesium oxide, calcium oxide, and zinc oxide, and examples of the carboxylic acid include capric acid, lauric acid, myristic acid, stearic acid, and behenic acid. Dry distillation and decarboxylation can be performed by, for example, cooling after high-temperature reaction in a salt bath under nitrogen blowing, adding an appropriate amount of an adsorbent at 100 to 110 ° C., stirring for 1 hour, and filtering. .

  The ketone compound containing the compound represented by the general formula (1) constituting the release agent for toner of the present invention contains a free fatty acid content of 0.5% by weight or less. From the viewpoint of chargeability and durability, the free fatty acid content is preferably 0.4% by weight or less, and more preferably 0.3% by weight or less. Further, the free fatty acid content is preferably as low as possible from the above viewpoint, but from the viewpoint of productivity and low-temperature fixability, the lower limit is preferably 0.05% by weight, more preferably 0.1% by weight. . In addition, in this invention, a free fatty acid means the unreacted fatty acid in the synthesis | combination of the said ketone compound, and the fatty acid used for the said reaction is mentioned.

The amount of the free fatty acid can be reduced by using an adsorbent that selectively adsorbs the free fatty acid during filtration. Examples of the adsorbent that selectively adsorbs free fatty acids include hydrotalcite, silicate, and other metal oxides and / or hydroxides. These may be used alone or in combination of two or more. Examples of the hydrotalcite include Mg ₆ Al ₂ (OH) ₁₆ CO ₃ .4H ₂ O and Mg _4.5 Al ₂ (OH) ₁₃ CO ₃ .3.5H ₂ O.
These are compounds obtained as a naturally occurring mineral or synthetically, and are known substances described in West German Patent Publication No. 1592126 and European Patent Publication No. 0207811. The ratio of Mg ²⁺ / Al ³⁺ in these natural or synthetic hydrotalcites is variable and is about 1 to 8, and the ratio of OH ⁻ / CO ₃ ²⁻ is also variable and is about 10 to 20. .

Examples of the silicate include 2MgO · 6SiO ₂ · xH ₂ O or Al ₂ O ₃ · 9SiO ₂ · xH ₂ O. As other oxides and / or hydroxides of one or more metals selected from the group consisting of aluminum, alkaline earth metals and alkali metals, for example, Al ₂ O ₃ .xH ₂ O, 2.5 MgO. _{Al 2 O 3 · xH 2 O} , Al 2 O 3 · Na 2 O · 2CO 3 · xH 2 O, or Mg _0.7 Al _0.3 O _1.15, and the like.
Of these, hydrotalcite and / or silicate are preferable, and more preferably, hydrotalcite is used as at least a part of the adsorbent, preferably 20% or more, more preferably 30 to 95%. Particularly preferably, Mg ₆ Al ₂ (OH) ₁₆ CO ₃ .4H ₂ O is used in the above amount.
As commercially available products suitably used as these adsorbents, for example, Kyowaad 100 (MgO), 500 (Mg 6 Al 2 (OH) 16 CO 3 · 4H 2 O), 600 (2MgO · 6SiO 2 · xH 2 O ), 600S include _{(2MgO · 6SiO 2 · xH 2} O), 1000 (Mg 4.5 Al 2 (OH) manufactured by _{13 CO 3 · 3.5H 2 O)} ( manufactured by Kyowa chemical industry Co., Ltd.).

The release agent for toner of the present invention preferably has an acid value of 1 mgKOH / mg or less, more preferably 0.9 mgKOH / mg or less, and further 0.8 mgKOH / mg or less from the viewpoint of chargeability and durability. preferable. In addition, in this invention, an acid value originates in the above-mentioned free fatty acid. The acid value of the release agent can be obtained by measuring the number of mg of potassium hydroxide required to neutralize the free fatty acid contained in the release agent.
In the toner release agent of the present invention, the hue is preferably 5 or less, more preferably 3 or less, in terms of Gardner color, from the viewpoint of a high-quality image and chargeability.
Further, the melting point of the release agent for toner of the present invention is preferably 60 to 140 ° C., more preferably 70 to 110 ° C., from the viewpoints of fixability and durability.

From the viewpoint of storage stability, low-temperature fixability and compatibility with the binder resin, the toner release agent of the present invention has a polar group concentration (carbon number excluding carbonyl group / number of carbonyl groups) of 20 to 50. Is preferable, and it is more preferable that it is 22-44.
The release agent for toner of the present invention can be used as a raw material for the binder resin during the production of the binder resin, or can be used as a toner raw material for the production of the toner.
When used as a toner raw material, in the melt-kneading and pulverizing method, the release agent for toner of the present invention and the raw material such as a binder resin are uniformly mixed with a mixer such as a Henschel mixer, and then a sealed kneader, a single screw or two It can be produced by melt-kneading with a shaft extruder, open roll type kneader or the like, cooling, pulverizing and classifying.

  In addition, as a wet manufacturing method, a mixed solution prepared by dissolving or dispersing a raw material containing a release agent for a toner of the present invention and a binder resin in an organic solvent is introduced into an aqueous medium and suspended. A method of forming fine particles by agglomeration and agglomerating the fine particles; emulsion polymerization of a radically polymerizable monomer solution in which a release agent for toner of the present invention and a binder resin are dissolved to obtain resin fine particles; A method of fusing in an aqueous medium (see Japanese Patent Application Laid-Open No. 2001-42568); a resin heating melt comprising a raw material containing a release agent for a toner of the present invention and a binder resin, Examples thereof include a method of dispersing in an aqueous medium not containing an organic solvent, followed by drying (see JP 2001-235904 A). Among these, (a) a step (1) of generating primary particles containing at least a release agent for toner of the present invention and a binder resin in an aqueous medium in the presence of a nonionic surfactant, and the primary And (b) a step (I), a step (I) of melt-kneading a toner raw material containing the binder resin and the toner release agent of the present invention. The method comprising the step (II) of emulsifying the melt-kneaded product obtained in step (II) in an aqueous medium and the step (III) of aggregating and coalescing the emulsified particles obtained in step (I) is preferred. From the viewpoint of dispersibility of the toner release agent, the method (b) is more preferable.

The toner for electrophotography of the present invention contains the above toner release agent and binder resin. Further, the electrophotographic toner of the present invention is preferably obtained by a method including a step of granulating in an aqueous medium or in a solution, and more preferably obtained by a method including a step of granulating in an aqueous medium. More preferably, a method obtained by a method including a step of granulating in an aqueous medium, preferably a step (I) of melt-kneading a polyester-containing binder resin and a toner raw material containing the toner release agent, And a step (II) of emulsifying the melt-kneaded product obtained in step (I) in an aqueous medium. The electrophotographic toner of the present invention will be described below.
The electrophotographic toner of the present invention is preferably obtained through a step (I) of melt-kneading a toner raw material containing a binder resin containing polyester and a release agent.

The binder resin used in the electrophotographic toner of the present invention contains polyester from the viewpoints of colorant dispersibility, fixability and durability. The content of the polyester is preferably 60% by weight or more, more preferably 70% by weight or more, still more preferably 80% by weight or more, and substantially 100% by weight from the viewpoint of fixing property and durability in the binder resin. Is more preferable.
Examples of binder resins other than polyester include known resins used in toners, such as styrene-acrylic resins, epoxy resins, polycarbonates, and polyurethanes.

The raw material monomer of the polyester is not particularly limited, and a known alcohol component and a known carboxylic acid component such as carboxylic acid, carboxylic acid anhydride, or carboxylic acid ester are used.
Examples of the alcohol component include alkylenes of bisphenol A such as polyoxypropylene-2,2-bis (4-hydroxyphenyl) propane and polyoxyethylene-2,2-bis (4-hydroxyphenyl) propane (carbon number of 2 to 3). ) Oxide (average addition mole number 1-16) adduct, ethylene glycol, propylene glycol, glycerin, pentaerythritol, trimethylolpropane, hydrogenated bisphenol A, sorbitol, or alkylene (2-4 carbon atoms) oxide (average) Addition mole number 1-16) Additions etc. are mentioned.

The carboxylic acid component includes dicarboxylic acids such as phthalic acid, isophthalic acid, terephthalic acid, fumaric acid, maleic acid, adipic acid and succinic acid, alkyl groups having 1 to 20 carbon atoms such as dodecenyl succinic acid and octenyl succinic acid, or carbon. Trivalent or higher polyvalent carboxylic acids such as succinic acid, trimellitic acid and pyromellitic acid substituted with alkenyl groups of 2 to 20, anhydrides of these acids and alkyls of these acids (1 to 3 carbon atoms) ) Esters and the like.
The polyester can be produced, for example, by subjecting an alcohol component and a carboxylic acid component to condensation polymerization at a temperature of 180 to 250 ° C. in an inert gas atmosphere, if necessary, using an esterification catalyst.

From the viewpoint of storage stability of the toner, the softening point of the polyester is preferably 80 to 165 ° C, and the glass transition point is preferably 50 to 85 ° C. The acid value is preferably 6 to 35 mgKOH / g, more preferably 10 to 35 mgKOH / g, and still more preferably 15 to 35 mgKOH / g, from the viewpoint of manufacturability during emulsification. The desired softening point and acid value can be obtained by adjusting the condensation polymerization temperature and reaction time.
From the viewpoint of the durability of the toner, the number average molecular weight of the polyester is preferably 1,000 to 10,000, and more preferably 2,000 to 8,000.
In addition, from the viewpoint of chargeability, as an acid component, aromatic carboxylic acids such as terephthalic acid, trimellitic acid, isophthalic acid, and anhydrides thereof, fumaric acid, adipic acid, succinic acid, and derivatives and anhydrides thereof It is preferable to use a polyester obtained by using an aliphatic carboxylic acid together.

The softening point of the binder resin is preferably 80 to 165 ° C, the glass transition point is preferably 50 to 85 ° C, and the acid value is preferably 4 to 35 mgKOH / g, more preferably 10 to 35 mgKOH / g, and 15 to 35 mgKOH / g. g is more preferable. When the binder resin contains a plurality of binder resins, the softening point, glass transition point and acid value of the binder resin are the softening point, glass transition point and acid value as a mixture of the binder resins. Means value.
Furthermore, it is preferable that the binder resin for toner of the present invention contains two types of polyesters having different softening points from the viewpoint of fixability and durability, and the softening point of one polyester (a) is 70. The softening point of the polyester of the other polyester (b) is preferably 115 ° C to 165 ° C.
The weight ratio (a / b) between the polyester (a) and the polyester (b) is preferably 10/90 to 90/10, and more preferably 50/50 to 90/10.

  As the release agent used in the electrophotographic toner of the present invention, the toner release agent of the present invention is used. If necessary, for example, a solid paraffin wax is used together with the toner release agent of the present invention. , Micro wax, rice wax, fatty acid amide wax, fatty acid wax, aliphatic monoketone, fatty acid metal salt wax, fatty acid ester wax, partially saponified fatty acid ester wax, silicone varnish, higher alcohol, carnauba wax, etc. Furthermore, polyolefins such as low molecular weight polyethylene and polypropylene can also be used.

The content of the release agent for toner of the present invention is 0.5 to 20 parts by weight, preferably 1 to 18 parts with respect to 100 parts by weight of the binder resin, from the viewpoint of dispersibility in the binder resin and fixability. Part by weight, more preferably 1.5 to 15 parts by weight.
Step (I) is a step of melt-kneading the toner raw material containing the binder resin containing polyester and the release agent of the present invention. It is preferable to mix the raw materials mechanically and uniformly before the melt-kneading step of step (I). That is, the mixing step of mechanically mixing the toner component including the binder resin containing polyester and the release agent for toner of the present invention and, if necessary, the colorant, the charge control agent, etc. There are no particular restrictions on the means.

The colorant is not particularly limited, and any known colorant can be used. Specifically, carbon black, inorganic composite oxide, chrome yellow, hansa yellow, benzidine yellow, sren yellow, quinoline yellow, permanent orange GTR, pyrazolone orange, vulcan orange, watch young red, permanent red, brilliantamine 3B, Brilliantamine 6B, DuPont Oil Red, Pyrazolone Red, Resol Red, Rhodamine B Lake, Lake Red C, Bengal, Methylene Blue Chloride, Phthalocyanine Blue, Phthalocyanine Green, Malachite Green Oxalate, Acridine, Xanthene, Azo Benzoquinone, azine, anthraquinone, indico, thioindico, phthalocyanine, aniline black, thiazole One of the various dyes and the like, alone or in combination of two or more can be used.
The content of the colorant is preferably 20 parts by weight or less, more preferably 0.01 to 10 parts by weight with respect to 100 parts by weight of the binder resin.

Examples of charge control agents include benzoic acid metal salts, salicylic acid metal salts, alkyl salicylic acid metal salts, catechol metal salts, metal-containing bisazo dyes, tetraphenylborate derivatives, quaternary ammonium salts, alkylpyridinium salts, and the like. Can be mentioned. These may be used individually by 1 type and may be used in combination of 2 or more type.
The content of the charge control agent is preferably 10 parts by weight or less, and more preferably 0.01 to 5 parts by weight with respect to 100 parts by weight of the binder resin.

When the above mixing process is completed, the mixture is charged into a kneader and melt-kneaded. It is important that this melt-kneading is performed under appropriate conditions so as not to cause the molecular chains of the binder resin to be broken and the charge control agent and the release agent to be excessively dispersed. Specifically, the melt kneading temperature should be performed with reference to the softening point of the binder resin and the melting point of the release agent. If the temperature is too low from the softening point, the molecular chain is severely cut, and if it is too high, the charge control agent. And the release agent does not disperse. From this point, specifically, the heating temperature of the melt-kneading is preferably 70 to 170 ° C, more preferably 80 to 160 ° C.
As the melt kneader for performing the melt kneading, a uniaxial or biaxial continuous kneader, a batch kneader by a roll mill, or an open roll kneader can be used. For example, KTK type manufactured by Kobe Steel, Ltd. Twin screw extruder, Toshiba Machine's TEM type extruder, Kay Sea Kay's twin screw extruder, Buss's kneader, Ikegai Iron Works's PCM type twin screw extruder, Open roll type continuous kneader, etc. Are preferably used. Among these, from the viewpoint of dispersibility of the release agent, a twin screw extruder and an open roll type kneader are preferable, and an open roll type kneader is more preferable. The twin screw extruder is preferably a PCM type twin screw extruder manufactured by Ikegai Iron Works, and the open roll type kneader is preferably an open roll type kneader manufactured by Mitsui Mining.

The open roll type kneader means a machine having at least two rolls and having an open type melt kneading unit. In the present invention, the kneader having at least two rolls of a heating roll and a cooling roll. Is preferably used. Such an open roll type kneader can easily dissipate kneading heat generated during melt kneading. The open roll kneader is preferably a continuous type from the viewpoint of production efficiency.
Further, in the open roll type kneader, the two rolls are arranged close to each other in parallel, and the gap between the rolls is preferably 0.01 to 5 mm, more preferably 0.05 to 2 mm. Further, the structure, size, material, and the like of the roll are not particularly limited, and the roll surface may be any of smooth, corrugated, uneven and the like.

The rotation speed of the roll, that is, the peripheral speed is preferably 2 to 100 m / min. The peripheral speed of the cooling roll is preferably 2 to 100 m / min, more preferably 10 to 60 m / min, and particularly preferably 15 to 50 m / min. The two rolls preferably have different peripheral speeds, and the ratio of the peripheral speeds of the two rolls (cooling roll / heating roll) is preferably 1/10 to 9/10. ˜8 / 10 is more preferable.
In order to make the kneaded material easily stick to the heating roll, the temperature of the heating roll is higher than both the softening point of the binder resin and the melting point of the release agent, and the temperature of the cooling roll is higher than the softening point of the binder resin. It is preferable that the temperature is adjusted to be lower than any temperature of the melting point of the mold. Specifically, the temperature of the heating roll is preferably 80 to 200 ° C, and the temperature of the cooling roll is preferably 20 to 140 ° C.

60-150 degreeC is preferable and the difference of the temperature of a heating roll and a cooling roll has more preferable 80-120 degreeC.
Note that the temperature of the roll can be adjusted by, for example, the temperature of the heat medium that passes through the inside of the roll.
The temperature of the heating roll, particularly the raw material charging side, is preferably higher than any of the softening point of the binder resin and the melting point of the release agent, and 0 to 80 ° C. higher than the higher one of them. Is more preferable, and it is still more preferable that it is 5-50 degreeC high. Further, the temperature of the cooling roll is preferably lower than any of the softening point of the binder resin and the melting point of the release agent, and is preferably 0 to 80 ° C. lower than the lower one of them. It is preferably 40 to 80 ° C. and particularly preferably. In addition, when a mold release agent contains a some mold release agent, melting | fusing point of the said mold release agent means melting | fusing point as a mixture of each mold release agent.

Step (II) is a step of emulsifying the melt-kneaded product obtained in step (I) in an aqueous medium.
The aqueous medium used in this step may contain a solvent such as an organic solvent, an inorganic salt such as an alkali metal salt, etc., but preferably contains 95% by weight or more, more preferably 99% by weight or more. In particular, in the present invention, it is preferable to use only water without substantially using an organic solvent from the viewpoint of atomizing the binder resin.
In the emulsification step, from the viewpoint of improving the emulsification stability of the binder resin, the amount is preferably 5 parts by weight or less, more preferably 0.1 to 3.5 parts by weight, and still more preferably with respect to 100 parts by weight of the binder resin. Preferably contains 0.1 to 3 parts by weight of a surfactant.

Examples of the surfactant include anionic surfactants such as sulfate ester type, sulfonate type, phosphate ester type, and soap type; cationic surfactants such as amine salt type and quaternary ammonium salt type; polyethylene Nonionic surfactants such as glycol-based, alkylphenol ethylene oxide adduct-based, polyhydric alcohol-based and the like can be mentioned. Among these, ionic surfactants such as anionic surfactants and cationic surfactants are preferable. The nonionic surfactant is preferably used in combination with an anionic surfactant or a cationic surfactant. Although the said surfactant may be used individually by 1 type, you may use it in combination of 2 or more type. Specific examples of the anionic surfactant include sodium dodecyl benzene sulfonate, sodium dodecyl sulfate, sodium alkyl ether sulfate, sodium alkyl naphthalene sulfonate, sodium dialkyl sulfosuccinate and the like.
Specific examples of the cationic surfactant include alkylbenzene dimethyl ammonium chloride, alkyl trimethyl ammonium chloride, distearyl ammonium chloride and the like.

In step (II), it is preferable to add an alkaline aqueous solution equivalent to the acid group of the polyester in the binder resin to disperse the melt-kneaded product obtained in step (I).
In the dispersion of the melt-kneaded product obtained in the step (I), the alkaline aqueous solution preferably has a concentration of 1 to 20% by weight, more preferably 1 to 10% by weight, and 1.5 to 7. More preferred is a concentration of 5% by weight. As for the alkali to be used, it is preferable to use an alkali that enhances the surface activity when the polyester becomes a salt. Examples thereof include monovalent alkali metal hydroxides such as potassium hydroxide and sodium hydroxide.
After dispersion, neutralize at a temperature above the glass transition point of the binder resin, and then add water at a temperature above the glass transition point to produce a binder resin emulsion by phase inversion emulsification. Can do.

The water addition rate is preferably 0.5 to 50 g / min, more preferably 0.5 to 40 g / min, and even more preferably 0.5 to 30 g per 100 g of resin from the viewpoint of effectively emulsifying. / Min. This addition rate is generally maintained until an O / W type emulsion is substantially formed, and there is no particular limitation on the addition rate of water after the formation of the O / W type emulsion.
Further, the temperature at this time is preferably in the range of not less than the glass transition point and not more than the softening point of the binder resin from the viewpoint of preparing a fine resin emulsion. By carrying out the emulsification at a temperature within the above range, the emulsification is carried out smoothly and no special apparatus is required for heating. From this point, the temperature is preferably a glass transition point of the binder resin + 10 ° C. or more, and preferably a softening point of −5 ° C. or less.

It is preferable that the emulsion of the melt-kneaded product thus obtained is subjected to the following step (III) of aggregating and coalescing the emulsified particles therein.
The volume-median particle size (D ₅₀ ) of the emulsified particles is preferably 0.02 to 2 μm, more preferably 0.05 to 1 μm, and still more preferably 0.05 to 0.05 in order to perform uniform aggregation in the aggregation process. 0.6 μm. In the present specification, the 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.

  In the aggregation step of step (III), it is preferable to perform a step of aggregating the binder resin in the presence of a surfactant in order to control the aggregation speed and the shape of the toner. When a surfactant is added in the step (II), it is not necessary to add it further, but it can be added if necessary. In the aggregation process, the amount of the surfactant present in the system is preferably 5 parts by weight or less, more preferably 4.5 parts by weight or less, more preferably 3 parts by weight or less with respect to 100 parts by weight of the binder resin, from the viewpoint of toner chargeability. More preferable is 5 parts by weight or less. Moreover, from a viewpoint of productivity and shape control, 0.5 weight part or more is preferable and 1 weight part or more is more preferable. That is, the amount of the surfactant present in the aggregation step is preferably 5 parts by weight or less, more preferably 0.5 to 4.5 parts by weight, and more preferably 0.5 to 3.5 parts by weight with respect to 100 parts by weight of the binder resin. Part by weight is more preferred.

The solid content concentration in the system in the coagulation step can be adjusted by adding water to the emulsion of the binder resin. In order to cause uniform aggregation and sharpen the particle size distribution, it is 10 to 50% by weight. Is preferable, 15 to 50% by weight is more preferable, and 15 to 40% by weight is further preferable.
The temperature in the system in the aggregation process is preferably a softening point of the binder resin of −50 ° C. or higher and a softening point of −10 ° C. or lower, more preferably a softening point of −30 ° C. or higher and a softening point of −10 ° C. or lower.

  In the aggregation step, it is preferable to add an aggregating agent in order to effectively perform aggregation. As the aggregating agent, a quaternary salt cationic surfactant, an organic aggregating agent such as polyethyleneimine, an inorganic aggregating agent such as an inorganic metal salt, an ammonium salt or a divalent or higher metal complex is used. Examples of inorganic metal salts include metal salts such as sodium sulfate, sodium chloride, calcium chloride, calcium nitrate, barium chloride, magnesium chloride, zinc chloride, aluminum chloride, aluminum sulfate, polyaluminum chloride, polyaluminum hydroxide, Examples thereof include inorganic metal salt polymers such as calcium sulfide. Examples of ammonium salts include ammonium halide, ammonium sulfate, ammonium acetate, ammonium benzoate, and ammonium salicylate. Examples of quaternary ammonium salts include tetraalkylammonium halides.

The amount of the flocculant used is preferably 30 parts by weight or less, more preferably 0.01 to 20 parts by weight, and more preferably 0.1 to 100 parts by weight with respect to 100 parts by weight of the binder resin, from the viewpoint of the aggregation ability and the environmental resistance characteristics of the toner. More preferred is 10 parts by weight.
The flocculant is preferably added after being dissolved in an aqueous medium, and it is preferable to sufficiently stir at the time of adding the flocculant and after the addition.

In the present invention, the agglomerated particles containing at least the polyester-containing binder resin and the release agent obtained in the aggregating step are heated and united (a uniting step).
The heating temperature for coalescing the aggregated particles is as follows: from the viewpoint of the target toner particle size, particle size distribution, shape control, and particle fusing property, the softening point of the binder resin is −55 ° C. or higher, and the softening point is +10. The softening point is preferably −50 ° C. or higher, the softening point + 10 ° C. or lower, more preferably the softening point −40 ° C. or higher, and the softening point + 10 ° C. or lower. Further, the stirring is preferably performed at a speed at which the aggregated particles do not settle.
In the present invention, the toner shape is changed from aggregated particles to coalesced particles by holding at the above temperature for a certain period of time.

A toner can be obtained by subjecting the coalesced particles obtained by the aggregation and coalescence process to a solid-liquid separation process such as filtration, a washing process, and a drying process as appropriate.
In the washing step, it is preferable to use an acid in order to remove metal ions on the toner surface in order to ensure sufficient charging characteristics and reliability as the toner. Moreover, it is preferable to completely remove the added surfactant by washing. The washing is preferably performed a plurality of times.
In the drying step, any method such as a vibration type fluidized drying method, a spray drying method, a freeze drying method, a flash jet method, or the like can be employed. The water content after drying of the toner is preferably adjusted to 1.5% by weight or less, more preferably 1.0% by weight or less, from the viewpoint of chargeability.

According to the present invention, a toner having a small particle size and a narrow particle size distribution suitable for high definition and high image quality can be obtained.
From the viewpoint of high image quality and productivity, the volume median particle size (D ₅₀ ) of the toner is preferably 1 to 7 μm, more preferably 2 to 7 μm, and even more preferably 3 to 7 μm.
Further, the softening point of the toner is preferably 60 to 140 ° C., more preferably 60 to 130 ° C., and further preferably 60 to 120 ° C. from the viewpoint of low-temperature fixability. Moreover, 30-80 degreeC is preferable from a durable viewpoint, and, as for a glass transition point, 40-70 degreeC is more preferable.

An auxiliary agent such as a fluidizing agent may be added to the toner particle surface as an external additive to the toner obtained by the present invention. External additives include known fine particles such as silica fine particles, titanium fine particles, alumina fine particles, cerium oxide fine particles, carbon black and other inorganic fine particles, and polymer fine particles such as polycarbonate, polymethyl methacrylate and silicone resin. Can be used.
The number average particle diameter of the external additive is preferably 4 to 200 nm, more preferably 8 to 100 nm, and still more preferably 8 to 50 nm. The number average particle diameter of the external additive is determined using a scanning electron microscope or a transmission electron microscope.

The amount of the external additive is preferably 1 to 5 parts by weight and more preferably 1.5 to 3.5 parts by weight with respect to 100 parts by weight of the toner before processing with the external additive. However, when hydrophobic silica is used as the external additive, the desired effect can be obtained by using 1 to 3 parts by weight of hydrophobic silica with respect to 100 parts by weight of the toner before processing with the external additive.
The toner for electrophotography obtained by the present invention can be used as a one-component developer or as a two-component developer by mixing with a carrier.

Each property value was measured and evaluated by the following method.
[Acid value of resin]
Measured according to the method of JIS K0070. However, only the measurement solvent was changed from a mixed solvent of ethanol and ether specified in JIS K0070 to a mixed solvent of acetone and toluene (acetone: toluene = 1: 1 (volume ratio)).

[Softening point of resin and toner, glass transition point and melting point of release agent]
(1) Softening point Using a flow tester (Shimadzu Corporation, CFT-500D), a 1 g sample was heated at a heating rate of 6 ° C./min, a load of 1.96 MPa was applied by a plunger, a diameter of 1 mm, a length Extrude from a 1 mm nozzle. Plot the flow tester's Bwanger drop amount against temperature, and let the softening point be the temperature at which half of the sample flowed out.
(2) Glass transition point of resin The temperature was raised from 20 ° C. to 200 ° C. using a differential scanning calorimeter (Seiko Denshi Kogyo Co., Ltd., DSC210), and the temperature was cooled to −10 ° C. at a temperature drop rate of 10 ° C./min. The sample is measured at a heating rate of 10 ° C./min, and the glass transition point is the temperature at the intersection of the base line extension below the maximum peak temperature and the tangential line showing the maximum slope from the peak rising portion to the peak apex. .
(3) Melting | fusing point of mold release agent It measures at a temperature increase rate of 5 degree-C / min from 20 degreeC using a differential scanning calorimeter (the Seiko Denshi Kogyo make, DSC210), and makes maximum peak temperature melting | fusing point.

[Number average molecular weight of resin]
The molecular weight distribution is measured by gel permeation chromatography and the number average molecular weight is calculated by the following method.
(1) Preparation of sample solution Dissolve in tetrahydrofuran so that the concentration is 0.5 g / 100 ml. Subsequently, this solution is filtered using a fluororesin filter having a pore size of 2 μm (FP-200, manufactured by Sumitomo Electric Industries, Ltd.) to remove insoluble components to obtain a sample solution.
(2) Molecular weight measurement Tetrahydrofuran is allowed to flow as a solution at a flow rate of 1 ml per minute, and the column is stabilized in a constant temperature bath at 40 ° C. 100 μl of the sample solution is injected therein and measurement is performed. The molecular weight of the sample is calculated based on a calibration curve prepared in advance. In this calibration curve, several types of monodisperse polystyrene (2.63 × 10 ³ , 2.06 × 10 ⁴ , 1.02 × 10 ⁵ manufactured by Tosoh Corporation), 2.10 × manufactured by GL Sciences Inc. 10 ³ , 7.00 × 10 ³ , 5.04 × 10 ⁴ ) are prepared as standard samples.
Measuring device: CO-8010 (manufactured by Tosoh Corporation)
Analysis column: GMHLX + G3000HXL (manufactured by Tosoh Corporation)

[Particle size of resin dispersed particles]
(1) Measuring apparatus: Laser scattering type particle size measuring machine (LA-920, manufactured by HORIBA, Ltd.)
(2) Measurement conditions: Distilled water is added to the measurement cell, and the volume-median particle size (D ₅₀ ) is measured at a temperature at which the absorbance is in an appropriate range.

[Toner particle size]
(1) Preparation of dispersion: 10 mg of a measurement sample was added to 5 ml of dispersion [“Emulgen 109P” (Kao, polyoxyethylene lauryl ether, HLB: 13.6) 5 wt% aqueous solution] Then, 25 ml of electrolyte [“Iston II” (manufactured by Beckman Coulter, Inc.)] is added and further dispersed for 1 minute with an ultrasonic disperser to obtain a dispersion.
(2) Measuring device: “Coulter Multisizer II” (Beckman Coulter, Inc.)
Aperture diameter: 50 μm
Analysis software: “Coulter Multisizer AccuComp version 1.19” (Beckman Coulter, Inc.)
(3) Measurement conditions: 100 ml of electrolyte solution and dispersion were added to a beaker, and the volume median particle size (D ₅₀ ) of 30,000 particles at a concentration at which the particle size of 30,000 particles could be measured in 20 seconds. Ask for.

[Method for measuring hue of release agent]
A colorimetric tube with an inner diameter of 10.65 ± 0.025 mm, a length of about 200 mm, and a measuring line that uses the reflected light of the filter paper with natural light from the north side as a light source and a light source with a marked line about 100 m from the bottom with a stopper. Insert up to the mark of the colorimetric tube. Next, the colorimetric tubes containing the sample and the standard solution are arranged in parallel, the color is compared by visually observing from the side with the light source on the back, and the number of the standard color solution that is closest to the sample color is determined. The number of Gardner colors. As the standard solution, a 1 L dilute hydrochloric acid solution of potassium chloroplatinate is used, a solution of 0.550 g of potassium chloroplatinate is designated as standard color number 1, and a solution of 0.865 g is sequentially added as a solution of standard color number 2; 1.330 g. Standard color number 3; 2.080 g of solution was standard color number 4; 3.035 g was standard color number 5.

[Method for measuring acid value of release agent]
Weigh 20 g of sample correctly in an Erlenmeyer flask, add 1% phenolphthalein indicator solution to toluene-ethanol mixture (2: 1), dissolve the mixed solvent neutralized in slight red just before use, and dissolve. Titrate with 0.1 mol / L alcoholic potassium hydroxide standard solution. The end point is a point where a slight red color lasts for 30 seconds.
The acid value (AV) is obtained from the following formula.
Acid value = (A × f × K) / sampled amount (g)
A: Amount of alcoholic potassium hydroxide standard solution required for titration (mL)
f: Factor of alcoholic potassium hydroxide standard solution
K: 5.611

[Method for measuring free fatty acid content]
When the acid value x (mg KOH / g), potassium hydroxide (molecular weight: 56.1) with respect to the release agent 1g because it will have been xmg (x × 10 ^-3 g) reaction,
Number of moles of free fatty acid contained in 1 g of mold release agent (mol) = x ÷ 56100
It becomes. Therefore, the ratio (% by weight) of the free fatty acid in the release agent is expressed by using z (g / mol) as the molecular weight of the acid of the release agent raw material.
Ratio of free fatty acid in mold release agent (% by weight) = (100 * z * x) / 56100
= (Z * x) / 561
Can be calculated.

Production example 1 of polyester
8320 g of polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, 80 g of polyoxyethylene (2.0) -2,2-bis (4-hydroxyphenyl) propane, 1592 g of terephthalic acid and 32 g of dibutyltin oxide (esterification catalyst) was reacted at normal pressure (101.3 kPa) and 230 ° C. for 5 hours under a nitrogen atmosphere, and further reacted under reduced pressure. After cooling to 210 ° C., 1672 g of fumaric acid and 8 g of hydroquinone were added and reacted for 5 hours, and further reacted under reduced pressure to obtain polyester resin A. Polyester resin A had a softening point of 110 ° C., a glass transition point of 66 ° C., an acid value of 24.4 mgKOH / g, and a number average molecular weight of 3760.

Production example 2 of polyester
17500 g of polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, 16250 g of polyoxyethylene (2.0) -2, 2-bis (4-hydroxyphenyl) propane, 11454 g of terephthalic acid, 1608 g of dodecenyl succinic anhydride, 4800 g of trimellitic anhydride and 15 g of dibutyltin oxide are placed in a four-necked flask equipped with a nitrogen introduction tube, a dehydration tube, a stirrer and a thermocouple, and stirred at 220 ° C. in a nitrogen atmosphere. The polyester resin B was obtained by reacting until the softening point measured according to ASTM D36-86 reached 120 ° C. Polyester resin B had a softening point of 121 ° C., a glass transition point of 65 ° C., an acid value of 18.5 mgKOH / g, and a number average molecular weight of 3394.

Production Example 1 of Ketone Compound
In a 1-liter SUS separable flask, 681 g (2.0 mol) of Lunac BA (behenic acid manufactured by Kao Corporation) and 44.3 g (1.1 mol) of magnesium oxide were weighed and heated to 250 ° C. by blowing nitrogen. The reaction was carried out for 5 hours to obtain magnesium behenate. At this time, water was distilled out of the system.
Thereafter, the temperature was further raised to 340 to 350 ° C., the reaction was continued for 8 hours, and then cooled to 100 ° C. to obtain a crude ketone compound 1. Adsorbent KYOWARD 600S (silicate manufactured by Kyowa Chemical Industry Co., Ltd .: 2MgO · 6SiO ₂ · xH ₂ O) and filter aid (Radiolite # 700, manufactured by Kyowa Chemical Industry Co., Ltd.) at 100 ° C. under nitrogen blowing Treatment was performed for 1 hour using diatomaceous earth). Thereafter, filtration was performed to remove excess magnesium oxide. The resulting ketone compound 1 (diheneicosyl ketone; R ¹ + R ² = 42) had an acid value (AV) of 0.32 mg KOH / g and a melting point of 99.3 ° C. Hue was Gardner 2.

Production Example 2 of Ketone Compound
In a 1-liter SUS separable flask, 572 g (2.0 mol) of Lunac S-98 (Kao Co., Ltd. stearic acid) and 44.3 g (1.1 mol) of magnesium oxide were weighed, and blown with nitrogen at 250 ° C. The mixture was heated up to react for 5 hours to obtain magnesium stearate. At this time, water was distilled out of the system. Thereafter, the temperature was further raised to 340 to 350 ° C., the reaction was continued for 8 hours, and then cooled to 100 ° C. to obtain a crude ketone compound 1. At 100 ° C. under nitrogen blowing, Kyward 600S (Kyowa Chemical Industry Co., Ltd. silicate: 2MgO.6SiO ₂ .xH ₂ O) as an adsorbent and Radiolite # 700 (Kyowa Kagaku Co., Ltd. diatomaceous earth) were added. The treatment was performed for 1 hour. Thereafter, filtration was performed to obtain ketone compound 2 (diheptadecyl ketone; R ¹ + R ² = 34) having an acid value (AV) of 0.67 mg KOH / g and a melting point of 96.8 ° C. Hue was Gardner 1-2.

Production Example 3 of Ketone Compound
In a 1-liter SUS separable flask, 546 g (2.0 mol) of lunac S-40 (a mixture of stearic acid / paltimic acid manufactured by Kao Corporation) and 44.3 g (1.1 mol) of magnesium oxide were weighed. The mixture was heated to 250 ° C. by nitrogen blowing and reacted for 5 hours to obtain a mixture of magnesium stearate and magnesium palmitate. At this time, water was distilled out of the system. Thereafter, the temperature was further raised to 340 to 350 ° C., the reaction was continued for 8 hours, and then cooled to 100 ° C. to obtain a crude ketone compound 3. The ketone in the molten state was filtered using a filter aid (Radiolite # 700, diatomaceous earth manufactured by Kyowa Chemical Industry Co., Ltd.) to remove excess magnesium oxide. The acid value (AV) of the obtained ketone compound 3 (mixture of diheptadecyl ketone / dipentadecyl ketone; R ¹ + R ² = 30 to 34) was 5.0 mgKOH / g, and the melting point was 86.1 ° C. . Hue was Gardner 4-5.

Production Example 4 of Ketone Compound
The crude ketone compound 3 was synthesized under the same conditions as the ketone compound 3, and the adsorbent KYOWARD 600S (silicate manufactured by Kyowa Chemical Industry Co., Ltd .: 2MgO · 6SiO ₂ · xH ₂ O) and Radiolite # 700 (Kyowa Chemical) Industrial diatomaceous earth) was added, and treatment was performed at 100 ° C. for 1 hour under nitrogen blowing. Thereafter, the mixture was filtered, and ketone compound 4 (mixture of diheptadecyl ketone / dipentadecyl ketone; R ¹ + R ² = 30 to 34) having an acid value (AV) of 0.37 mg KOH / g and a melting point of 84.5 ° C. Obtained. Hue was Gardner 2.

Production Example 5 of Ketone Compound
In a 1-liter SUS separable flask, 513 g (2.0 mol) of Lunac P-95 (palmic acid manufactured by Kao Corporation) and 44.3 g (1.1 mol) of magnesium oxide were weighed and blown with nitrogen at 250 ° C. The mixture was heated up to react for 5 hours to obtain magnesium palmitate. At this time, water was distilled out of the system. Thereafter, the temperature was further raised to 340 to 350 ° C., the reaction was continued for 8 hours, and then cooled to 100 ° C. to obtain crude dimyristyl ketone. The adsorbent KYOWARD 600S (Kyowa Chemical Industry Silicate: 2MgO 6SiO ₂ xH ₂ O) 3.9 g and filter aid (Radiolite # 700 Kyowa Chemical Industry diatomaceous earth at 100 ° C. under nitrogen blowing )) For 1 hour. Thereafter, filtration was performed to remove excess magnesium oxide. The resulting ketone compound 5 (mixture of dipentadecyl ketone; R ¹ + R ² = 30) had an acid value (AV) of 0.46 mg KOH / g and a melting point of 90.6 ° C. Hue was Gardner 2.

Toner kneaded product production example 1
After mixing the raw materials comprising the following components for 3 minutes at a stirring speed of 1500 r / m using a 20 L Henschel mixer, it is melt-kneaded using an open roll type continuous kneader “NIDEX” (Mitsui Mining Co., Ltd.) The obtained toner kneaded product was cooled with a cooling belt and then roughly crushed with a mill having a 2 mmφ screen to obtain a toner kneaded product a. The softening point of the binder resin composed of polyester resins A and B was 114 ° C., the glass transition point was 65 ° C., and the acid value was 22.3.
(material)
・ Polyester resin A 2600g
・ Polyester resin B 1400g
・ Ketone compound 1 200g
ECB-301 (copper phthalocyanine pigment: manufactured by Dainichi Seika Kogyo Co., Ltd.) 200 g

  The used open roll type continuous kneader “NEDEX” has a roll outer diameter of 0.14 m and an effective roll length of 0.8 m. The rotation speed of the cooling roll (rear roll) was 22 m / min, and the roll gap was 0.1 mm. The heating and cooling medium temperatures in the roll are 150 ° C. on the raw material input side of the heating roll, 130 ° C. on the kneaded material discharge side, 35 ° C. on the raw material input side of the cooling roll, and the kneaded material discharge side. Was set to 30 ° C. The feed rate of the raw material mixture was 5 kg / hour, and the average residence time was about 5 minutes.

Toner kneaded product production example 2
A toner kneaded product b was produced in the same manner as in the toner kneaded product production example 1 except that the ketone compound 1 was changed to the ketone compound 2.

Toner kneaded product production example 3
A toner kneaded product c was produced in the same manner as in the toner kneaded product production example 1 except that the ketone compound 1 was changed to the ketone compound 4.

Toner kneaded product production example 4
A toner kneaded product d was produced in the same manner as in the toner kneaded product production example 1 except that the ketone compound 1 was changed to the ketone compound 5.

Toner kneaded product production example 5
A toner kneaded product e was produced in the same manner as in the toner kneaded product production example 1 except that the ketone compound 1 was changed to the ketone compound 3.

Example 1
In a 5-liter stainless steel kettle, 660 g of toner kneaded material a, 6.0 g of nonionic surfactant “Emulgen 430 (manufactured by Kao)” 6.0 g of polyoxyethylene oleyl ether (HLB: 16.2), anionic surfactant “ Neoperex G-15 (manufactured by Kao) "40.0 g of sodium dodecylbenzenesulfonate aqueous solution (concentration: 15 wt%) and 252 g of potassium hydroxide aqueous solution (concentration: 5 wt%) as a neutralizing agent were added. The mixture was dispersed at 95 ° C. with stirring at 200 r / min. The contents were stirred for 2 hours after reaching 95 ° C., and then 986.31 g of deionized water was added dropwise at a rate of 6 g / min with stirring at 150 r / min with a chi-type stirrer, and 200 mesh (opening: A finely divided toner dispersion was obtained through a wire mesh of 105 μm). The volume-average particle size of the particles in the obtained toner dispersion was 0.171 μm, the solid concentration was 35.03 wt%, and no resin component remained on the wire mesh.

350 g of the obtained dispersion was mixed at room temperature in a 2 liter container. Next, under stirring at 100 r / min with a Kai-type stirrer, 10.83 g of ammonium sulfate (special grade made by Sigma-Aldrich Japan) as a flocculant and cation-modified polyvinyl alcohol (K-210 (Japan) as a hydrophilic polymer were added to this mixture. A solution prepared by dissolving 8.21 g of a 5% by weight aqueous solution of Synthetic Chemical Industry Co., Ltd.) in 59.16 g of deionized water was added dropwise at room temperature over 60 minutes. Thereafter, the mixed dispersion was heated at 1 ° C./min to form aggregated particles, and when the temperature reached 80 ° C., the temperature was raised to 90 ° C. at 0.17 ° C./min. Then, after fixing at 90 degreeC and stirring for 4 hours, the heating was stopped. During this time, the toner shape changed from aggregated particles to coalesced particles.
The solution was gradually cooled to room temperature, and colored resin fine particle powder was obtained through a suction filtration step, a washing step and a drying step. The volume median particle size (D ₅₀ ) of the colored resin fine particle powder was 3.1 μm, and the water content was 0.3% by weight.
To 100 parts by weight of the colored resin fine particle powder, 1.0 part by weight of hydrophobic silica (manufactured by Wacker Chemie, TS530, primary number average particle diameter: 8 nm) was externally added using a Henschel mixer to obtain a cyan toner. . With the obtained cyan toner, a good image was obtained with a commercially available full color printer. The glass transition point was 55.0 ° C.

Example 2
A toner was prepared in the same manner as in Example 1 except that the toner kneaded product a was changed to the toner kneaded product b. The volume median particle size (D ₅₀ ) of the resin particles in the obtained resin dispersion was 0.140 μm, and the solid concentration was 35.61% by weight. The volume-average particle size (D ₅₀ ) of the colored resin fine particles after aggregation and coalescence was 8.0 μm, and the water content was 0.2% by weight.
1.0 part by weight of hydrophobic silica (manufactured by Wacker Chemie, TS530, primary number average particle diameter: 8 nm) is added externally using a Henschel mixer to 100 parts by weight of the colored resin fine particle powder to obtain a cyan toner. . With the obtained cyan toner, a good image was obtained with a commercially available full color printer. The glass transition point was 49.7 ° C.

Example 3
A toner was prepared in the same manner as in Example 1 except that the toner kneaded product a was changed to the toner kneaded product c. The resin particles in the obtained resin dispersion had a volume median particle size (D ₅₀ ) of 0.154 μm and a solid concentration of 35.83% by weight. The volume-average particle size (D ₅₀ ) of the colored resin fine particles after aggregation and coalescence was 4.5 μm, and the water content was 0.2% by weight.
1.0 part by weight of hydrophobic silica (manufactured by Wakker Chemie, TS530, primary number average particle size: 8 nm) is added externally using a Henschel mixer to 100 parts by weight of the colored resin fine particle powder to obtain a cyan toner. With the obtained cyan toner, a good image was obtained with a commercially available full color printer. The glass transition point was 46.9 ° C.

Example 4
A toner was prepared in the same manner as in Example 1 except that the toner kneaded product a was changed to the toner kneaded product d. The volume median particle size (D ₅₀ ) of the resin particles in the obtained resin dispersion was 0.141 μm, and the solid concentration was 35.55% by weight. The volume-median particle size (D ₅₀ ) of the colored resin fine particles after aggregation and coalescence was 4.7 μm, and the water content was 0.3% by weight.
1.0 part by weight of hydrophobic silica (manufactured by Wacker Chemie, TS530, primary number average particle diameter: 8 nm) is added externally using a Henschel mixer to 100 parts by weight of the colored resin fine particle powder to obtain a cyan toner. . With the obtained cyan toner, a good image was obtained with a commercially available full color printer. The glass transition point was 44.8 ° C.

Comparative Example 1
A toner was prepared in the same manner as in Example 1 except that the toner kneaded material a was changed to the toner kneaded material e. The resin particles in the obtained resin dispersion had a volume-median particle size (D ₅₀ ) of 0.152 μm and a solid concentration of 35.57% by weight. The volume-median particle size (D ₅₀ ) of the colored resin fine particles after aggregation and coalescence was 4.8 μm, and the water content was 0.2% by weight.
To 100 parts by weight of the colored resin fine particle powder, 1.0 part by weight of hydrophobic silica (manufactured by Wacker Chemie, TS530, primary number average particle diameter: 8 nm) was externally added using a Henschel mixer to obtain a cyan toner. . With the obtained cyan toner, a good image was obtained with a commercially available full color printer. The glass transition point was 47.8 ° C.

Each of the toners of Examples 1 to 4 and Comparative Example 1 was evaluated for low-temperature fixability and durability by the following method. The results are shown in Table 1.
<Minimum fixing temperature>
With respect to the obtained toner, the minimum fixing temperature was examined using an oilless fixing unit of a non-magnetic one-component electrophotographic printer capable of 23 A4 portrait printing per minute. For the minimum fixing temperature, a solid image is pasted on a mending tape, and when it is peeled off, the change in the image density is checked, and the image density after peeling is fixed at 90% or more of the original image density. It was judged that
A: Fixing is possible even at a temperature of 140.degree. C. or lower. A temperature of 141.degree. C. or higher and 150.degree. C. or lower was the lowest fixing temperature. X: A temperature of 151.degree. C. or higher was the lowest fixing temperature.

<Durability>
With respect to the obtained toner, 80 g of toner is attached to the developing unit of a non-magnetic one-component electrophotographic printer, and a jig is prepared so that the developing unit can be stirred and rotated in the same manner as the actual speed, and stirred for 30 minutes. When this was done, the appearance of streaks on the developing roll was observed.
A: No more than 2 streaks and no problem with durability.
○: There are 3 to 5 streaks, and there is no problem in durability.
(Triangle | delta): There is no problem in durability in actual use at 6-10 lines.
X: There are 11 streaks or more in actual use.

以上より、実施例のトナーは、比較例のものと対比して、良好な低温定着性及び耐久性という相反する特性を両立して改善することが分かる。

From the above, it can be seen that the toners of the examples improve both contradictory properties such as good low-temperature fixability and durability as compared with the comparative examples.

  The present invention relates to a toner release agent capable of achieving both excellent low-temperature fixability and durability, and an electrophotographic toner containing the release agent and excellent in both low-temperature fixability and durability. The toner of the present invention can be suitably used as a one-component developer for electrophotography or a two-component developer mixed with a carrier.

Claims (5)

A toner release agent comprising a ketone compound containing a compound represented by the following general formula (1) and having a free fatty acid content of 0.5% by weight or less.

(In the formula, R ¹ and R ² are each an aliphatic hydrocarbon group or an aromatic hydrocarbon group, and the total carbon number of R ¹ and R ² is 20 to 50.)   The toner release agent according to claim 1, which has an acid value of 1 mg KOH / mg or less.   An electrophotographic toner comprising the toner release agent according to claim 1 or 2 and a binder resin.   4. The toner for electrophotography according to claim 3, obtained by a method comprising a step of granulating in an aqueous medium or in a solution.   Step (I) of melt-kneading a toner raw material containing a binder resin containing polyester and a release agent according to claim 1 or 2, and the melt-kneaded product obtained in step (I) in an aqueous medium An electrophotographic toner obtained by a method comprising an emulsifying step (II).