JP2008256846A - Method for manufacturing yellow toner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a yellow toner by which a toner having a controlled particle diameter can be easily manufactured in a short manufacture time, red discoloration of a pigment can be suppressed and a process load can be significantly decreased. <P>SOLUTION: The method includes steps of: (1) mixing at least a binder resin containing a polyester having an acid group with a C.I.pigment yellow 93 (Color Index Pigment Yellow 93); and (2) producing emulsified particles of the binder resin containing the C.I.pigment yellow 93 in an aqueous medium. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for producing a yellow toner used in electrophotography, electrostatic recording method, electrostatic printing method and the like.

Emulsion polymerization methods and emulsion dispersion methods are known as methods for producing chemical toners. Among these methods, a method for producing a toner by an emulsification dispersion method is a method in which, for example, a mixture of a binder resin and a colorant is mixed with an aqueous medium and emulsified to obtain toner particles. In this method, for example, when polyester is used as the binder resin, the operation may be complicated, the production time may be long, and shape control may not be possible. In addition, an alkali is added to the emulsification step to make the polyester terminal a salt. When the reaction is included, there is also a problem that the yellow pigment turns red upon alkali addition.
As a technique for obtaining toner from a binder resin containing polyester and a colorant in an aqueous medium, for example, a binder resin containing 50 to 100% by weight of a polyester resin in an aqueous medium, and a colorant and a basic polymer copolymer A technique for improving dispersibility and the like by using an image forming toner (see Patent Document 1) generated from a coloring component containing a systemic dispersant and a pigment derivative is disclosed. In such a technique, a binder resin is disclosed. Since an organic solvent is used for dispersion, the types of resins that can be used are limited, and there are problems such as an increase in process load such as solvent recovery.

JP 2005-181835 A

  The present invention relates to a method capable of producing a toner having a controlled particle size easily and in a short production time even when a binder resin containing polyester is used. The present invention also relates to a method for producing a yellow toner capable of suppressing redness of a pigment and greatly reducing the process load.

The present invention
(A) (1) At least a binder resin containing a polyester having an acid group and C.I. I. Pigment Yellow 93 (Color Index Pigment Yellow 93) and (2) in an aqueous medium, C.I. I. A process for producing emulsified particles of the binder resin containing CI Pigment Yellow 93,
(B) The method further comprises the step of agglomerating the emulsified particles in an aqueous medium, and (c) the yellow toner production method according to (a), and (c) the production method according to (a) or (b) above. Yellow toner,
About.

  According to the method for producing a yellow toner of the present invention, even when a binder resin containing polyester is used, a toner having a controlled particle size can be produced easily and in a short production time, and the redness of the pigment can be changed. And the process load can be greatly reduced.

  The present invention relates to (1) a binder resin containing at least a polyester having an acid group and C.I. I. Yellow having a step of mixing Pigment Yellow 93 (hereinafter referred to as PY93), and (2) a step of producing emulsified particles of the binder resin containing PY93 in an aqueous medium. The present invention relates to a toner manufacturing method. Below, the said process (1) and process (2) are demonstrated.

Process (1)
Step (1) is to mix at least a binder resin containing a polyester having an acid group and PY93.
The binder resin used in the method for producing a yellow toner of the present invention contains a polyester having an acid group from the viewpoints of colorant dispersibility, fixability and durability. The content of the polyester having an acid group is preferably 60% by weight or more, more preferably 70% by weight or more, and still more preferably 80% by weight or more from the viewpoints of fixability and durability in the binder resin. Examples of the binder resin other than the polyester having an acid group include known resins used for toner, for example, styrene-acrylic resin, epoxy resin, polycarbonate, polyurethane and the like.

Although the raw material monomer of the polyester having an acid group is not particularly limited, a known alcohol component and a known carboxylic acid component such as a carboxylic acid, a carboxylic acid anhydride, or a 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 their alkylene (2-4 carbon atoms) oxide (average) Addition mole number 1-16) Additions etc. are mentioned. This alcohol component may be used individually by 1 type, and may be used in combination of 2 or more type.

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 having an acid group is produced, for example, by subjecting the alcohol component and the carboxylic acid component to polycondensation at a temperature of 180 to 250 ° C. using an esterification catalyst as necessary in an inert gas atmosphere. be able to.

  From the viewpoint of the storage stability of the toner, the softening point of the polyester having an acid group is preferably 80 to 165 ° C, and the glass transition temperature 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.

  The polyester having an acid group may be a polyester modified to such an extent that the characteristics are not substantially impaired. Examples of the modified polyester include grafting and blocking with phenol, urethane, epoxy and the like by the methods described in JP-A-11-133668, JP-A-10-239903, JP-A-8-20636, and the like. Polyester.

In the present invention, PY93 is used as a colorant and is represented by the following structural formula.

Conventionally, as a yellow pigment of toner, C.I. I. In many cases, CI Pigment Yellow 17 is used, but in recent years, use of a dichlorobenzidine-free yellow pigment is desired in consideration of the environment. Examples of the dichlorobenzidine-free yellow pigment include C.I. I. Pigment Yellow 180, 185, 151, 154, 155, 167, 139, 93, etc. are known, and among these, C.I. I. Pigment Yellow 180, 185, and 93 were widely used.
However, in the production of a polyester-based toner including a reaction in which an alkali is added in the emulsification step to make the polyester terminal a salt, when using a yellow pigment, there is a problem that the yellow pigment turns red upon alkali addition. It was also necessary to consider the choice of pigment.

From the above points, the present inventors have found that PY93 is particularly effective among the above yellow pigments from the viewpoints of alkali resistance, dispersibility of the pigment in the polyester, and the like.
In the present invention, if necessary, other yellow toners can be used together with PY93 as long as the yellow pigment does not impair the object of the present invention. Therefore, it is preferable that only PY93 is used.
In the step (1), the binder resin containing the polyester having an acid group and PY93 are mixed. From the viewpoint of uniformly dispersing the resin particles and PY93, the binder resin is less than the softening point. It is preferable to carry out the mixing at a temperature of By mixing at a temperature lower than the softening point of the binder resin, fusion between the resin particles can be suppressed, and a uniform resin dispersion can be prepared. Further, from the viewpoint of dispersibility of the pigment, it is also a preferred embodiment that the colorant is used as a master batch. The resin used for the master batch is preferably a polyester having an acid group, and is preferably a polyester used in the mixing step of step (1). Specifically, in a basic aqueous medium containing a surfactant, a binder resin containing a polyester having an acid group and a colorant masterbatched using the polyester having an acid group are combined with the binder. It is preferable to mix and stir at a temperature lower than the softening point of the resin.

  In the step (1), when the binder resin containing the polyester having an acid group and the colorant are mixed with the colorant in a master batch, for example, use of the resin used for the master batch and PY93 The ratio (resin / PY93 used in the masterbatch) is preferably 14/86 to 70/30 parts by weight, more preferably 28/72 to 57/43 parts by weight, and 35/65 to 50/50 parts by weight. Further preferred. In addition, the total amount of the binder resin containing the polyester having an acid group in step (1) (including the resin used in a masterbatch) and the use ratio of PY93 (the binder resin containing the polyester having an acid group) From the viewpoint of pigment dispersibility and toner productivity, the total amount / PY93) is preferably 90/10 to 97/3, more preferably 92/8 to 97/3 in terms of weight ratio.

Process (2)
Step (2) is a step of producing emulsified particles of a binder resin containing the PY93 in an aqueous medium.
The aqueous medium used in the step (2) preferably contains 95% by weight or more, more preferably 99% by weight or more of water, and contains a solvent such as an organic solvent, an inorganic salt such as an alkali metal salt, and the like. It may be. In the present invention, it is particularly preferable to atomize the binder resin containing PY93 by using only water without substantially using an organic solvent.
In the step (2), from the viewpoint of improving the emulsification stability of the binder resin containing PY93, it is preferably 5 parts by weight or less, more preferably 0.1-3. 5 parts by weight, more preferably 0.1 to 3 parts by weight of a surfactant is present.

  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 preferably used. The nonionic surfactant is preferably used in combination with an anionic surfactant or a cationic surfactant.

  Specific examples of the anionic surfactant include sodium dodecylbenzenesulfonate, sodium dodecylsulfate, sodium alkyl ether sulfate, sodium alkylnaphthalenesulfonate, sodium dialkylsulfosuccinate and the like. Specific examples of the cationic surfactant include alkylbenzene dimethyl ammonium chloride, alkyl trimethyl ammonium chloride, distearyl ammonium chloride and the like. Specific examples of the nonionic surfactant include polyoxyethylene alkyl ether, polyoxyethylene alkylphenyl ether, sorbitan monostearate, polyoxyethylene alkylamine and the like. Each of the surfactants may be used alone or in combination of two or more.

In the step (2), it is preferable to add an alkaline aqueous solution, and an alkaline aqueous solution equivalent to the acid group of the polyester having an acid group in the binder resin is added to emulsify the binder resin containing PY93. Is more preferable.
In the emulsification of the binder resin containing PY93, the concentration of the aqueous alkali solution added is preferably 1 to 20% by weight, more preferably 1 to 10% by weight, and even more preferably 1.5 to 7.5% by weight. Further, from the viewpoint of easily neutralizing the polyester having an acid group, a strongly basic alkali having a pH value of 13 to 15 at 25 ° C. is used. As the alkali to be used, it is preferable to use an alkali that enhances its surface activity when the polyester becomes a salt. Specific examples thereof include hydroxylation of monovalent alkali metals such as potassium hydroxide and sodium hydroxide. Such as things.
From the viewpoint of emulsion stability, the pH value of the emulsion is preferably 5.6 to 8, more preferably 5.8 to 7.

  In the step (2), a charge adjusting agent, a release agent and the like can be used together with the binder resin and PY93. In addition, it is not limited to the form of the binder resin, and the toner raw material such as a colorant previously melted and kneaded into the resin may be granulated and dispersed.

  As release agents, low molecular weight polyolefins such as polyethylene, polypropylene and polybutene; silicones having a softening point upon heating; fatty acid amides such as oleic acid amide, erucic acid amide, ricinoleic acid amide and stearic acid amide; carnauba Plant waxes such as wax, rice wax, candelilla wax, tree wax, jojoba oil; animal waxes such as beeswax; mineral and petroleum systems such as montan wax, ozokerite, ceresin, paraffin wax, microcrystalline wax, Fischer-Tropsch wax Wax etc. are mentioned. These release agents can be used as they are or dispersed in an aqueous medium. The content of the release agent is usually about 1 to 20 parts by weight, preferably 2 to 15 parts by weight with respect to 100 parts by weight of the binder resin in consideration of the addition effect and the adverse effect on the chargeability.

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. 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.
Specifically, after PY93 is dispersed in the binder resin in the step (1), in the step (2), after neutralization at a temperature equal to or higher than the glass transition point of the binder resin, the glass transition point or higher is reached. Resin-emulsified particles can be produced by phase inversion emulsification by adding water at a temperature of 5 ° C.
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 less than the softening point of the binder resin from the viewpoint of preparing a fine PY93-containing resin emulsion, and more preferably in the range of the glass transition point of the binder resin and less than the softening point. preferable. 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 not less than the glass transition point of the binder resin + 10 ° C. (meaning a temperature 10 ° C. higher than the glass transition point, the same shall apply hereinafter), and the softening point should be −5 ° C. or less. Is preferred. When the binder resin is a mixture of a plurality of binder resins, the softening point and glass transition point are calculated by multiplying the softening point of each binder resin and the mixing ratio of the glass transition points. When is used, the softening point of the mixed resin including the resin used therein is used.

The solid content concentration of the resin emulsion thus obtained is 5 to 50 from the viewpoint of causing stability of the emulsion and handling of the resin emulsion in the aggregation step to be performed later, and uniform aggregation. % By weight is preferred, 5 to 45% by weight is more preferred, and 10 to 40% by weight is even more preferred.
The volume median particle size (D ₅₀ ) of the resin emulsified particles containing PY93 is preferably 0.05 to 3 μm, more preferably 0.05 to 1 μm, from the viewpoint of performing uniform aggregation in the subsequent aggregation process. 0.05 to 0.8 μm is more preferable.
The obtained resin emulsion is preferably aggregated and united by subjecting the emulsified particles containing PY93 therein to the following step (3).

Step (3)
Step (3) is a step of aggregating the emulsified particles in an aqueous medium.
In the present invention, the emulsified particles in the resin emulsion containing PY93 obtained in the above step (2) are aggregated (hereinafter referred to as the aggregation step), more preferably combined (hereinafter referred to as the integration step). As a result, a yellow toner can be obtained.
In the aggregation step, the pH value in the system is preferably 2 to 10, more preferably 2 to 9, from the viewpoint of achieving both the dispersion stability of the mixed solution and the aggregation property of the fine particles of the binder resin containing PY93. 3-8 are more preferable.
From the same viewpoint, the temperature in the system in the aggregation step is preferably a softening point of the binder resin of −70 ° C. or higher and a softening point of −10 ° C. or lower, more preferably a softening point of −60 ° C. or higher and a softening point of −10 ° C. or lower. .
As the aqueous medium used in the aggregation step, the same media as those mentioned in the above step (2) can be used.

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. In the present invention, it is preferable to use a monovalent salt as the flocculant from the viewpoint of achieving highly accurate toner particle size control and a sharp particle size distribution. Here, the monovalent salt means that the valence of the metal ion or cation constituting the salt is 1. As the monovalent salt, organic flocculants such as quaternary salt cationic surfactants, inorganic flocculants such as inorganic metal salts and ammonium salts are used. From the viewpoint of achieving particle size control and a sharp particle size distribution, a water-soluble nitrogen-containing compound having a molecular weight of 350 or less is preferably used.

  The water-soluble nitrogen-containing compound having a molecular weight of 350 or less is preferably a compound exhibiting acidity from the viewpoint of rapidly agglomerating resin particles, and a 10% by weight aqueous solution having a pH value of 4 to 6 at 25 ° C. Are preferable, and 4.2 to 6 are more preferable. From the viewpoint of chargeability at high temperature and high humidity, the molecular weight is preferably 350 or less, more preferably 300 or less. Examples of such water-soluble nitrogen-containing compounds include ammonium salts such as ammonium halide, ammonium sulfate, ammonium acetate, ammonium benzoate and ammonium salicylate, and quaternary ammonium salts such as tetraalkylammonium halide. From the viewpoint of properties, ammonium sulfate (pH value of a 10% by weight aqueous solution at 25 ° C., hereinafter referred to as “pH value”: 5.4), ammonium chloride (pH value: 4.6), tetraethylammonium bromide (pH value: 5) .6) and tetrabutylammonium bromide (pH value: 5.8) are preferred.

The amount of the flocculant used varies depending on the valence of the charge of the flocculant used, but when a monovalent flocculant is used, 2 to 50 wt. Part is preferable, 3.5 to 40 parts by weight is more preferable, and 3.5 to 30 parts by weight is further preferable.
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. The obtained aggregated particles are preferably subjected to a step of coalescing the aggregated particles (unification step).
From the viewpoint of high image quality, the volume-median particle size of the aggregated particles is preferably 1 to 10 μm, more preferably 2 to 8 μm, and further preferably 3 to 7 μm.

In the present invention, the PY93 obtained in the step (2) is contained at the time of aggregation from the viewpoint of preventing the release of a release agent or the like, and making the charge amount between each color the same level in the color toner. Other resin emulsified particles can be added to the resin emulsified particles.
The resin emulsified particles to be added are not particularly limited, and for example, those prepared in the same manner as the resin emulsified particles in the step (2) can be used.
In addition to the binder resin, the other resin-emulsified particles can appropriately contain additives such as a colorant, a release agent, a charge control agent, and a surfactant and a fixability improver as necessary. .
In the present invention, the other resin emulsified particles may be the same as or different from the resin emulsified particles obtained in the step (2) of the present invention.
In this step, the other resin emulsified particles may be mixed with the aggregated particles obtained by adding an aggregating agent to the resin emulsion obtained in step (2).

In the present invention, the addition timing of the other resin-emulsified particles is not particularly limited, but is preferably between the end of addition of the flocculant and the coalescence step from the viewpoint of productivity.
The addition amount of the other resin emulsified particles to the aggregated particles is a resin constituting the resin emulsified particles to be added to 100 parts by weight of the resin in the aggregated particles from the viewpoint of uniformly coating the aggregated particles with the resin emulsified particles. However, the amount is preferably 5 to 100 parts by weight, more preferably 10 to 90 parts by weight, and still more preferably 20 to 80 parts by weight.
In the said process, said other resin emulsification particle | grains can be divided | segmented and added in 1 time or in multiple times. In the present invention, from the viewpoint of achieving a narrow particle size distribution of the obtained toner particles, it is preferable to add the toner particles in a plurality of divided portions.

  When adding other resin emulsified particles divided into one or more times, the resin constituting the added resin emulsified particles is added in an amount of less than 30 parts by weight from the viewpoint of controlling the particle size distribution of the formed aggregated particles. In this case, the addition of the flocculant is optional. In the case of adding 30 parts by weight or more, it is preferable to add an aggregating agent from the viewpoint of aggregating property and the particle size distribution of the aggregated particles to be formed, and the above-mentioned aggregating agents can be used similarly. In this case, it is more preferable to add the resin emulsified particles and the flocculant independently at the same time or alternately, and it is more preferable to add them independently and simultaneously.

In this step, when adding other resin emulsified particles divided into a plurality of times, the amount of each resin emulsified particle is preferably the same amount, and when adding the flocculant dividedly, Each flocculant is preferably the same amount.
As described above, when the other resin-emulsified particles are added in a plurality of divided portions, the number of times is not particularly limited, but 2-10 times from the viewpoint of the particle size distribution and productivity of the formed aggregated particles. Is preferable, and 2 to 8 times is more preferable.
In addition, from the viewpoint of cohesiveness and the particle size distribution of the formed aggregated particles, in the addition of the resin emulsified particles multiple times, 5 to 15 minutes after the addition, further 5 to 30 minutes, especially 5 minutes to 2 hours. It is preferable to make it age | cure | ripen, and it is more preferable to provide the said ageing | curing | ripening time in each addition of multiple times addition.

In the present invention, it is preferable to add a surfactant such as an alkyl ether sulfate, an alkyl sulfate, or a linear alkyl benzene sulfonate after the resin emulsified particles are aggregated.
As the alkyl ether sulfate, those represented by the following formula (1) are preferable.
R ¹ —O— (CH ₂ CH ₂ O) pSO ₃ M ¹ (1)
In the formula, R ¹ represents an alkyl group, and preferably an alkyl group having 6 to 20 carbon atoms, more preferably 8 to 15 carbon atoms, from the viewpoint of adsorptivity to aggregated particles and persistence to toner. p represents an average added mole number of 0 to 15, and is preferably 1 to 10, more preferably 1 to 5, from the viewpoint of particle size control. M ¹ represents a monovalent cation, and is preferably sodium, potassium, or ammonium, more preferably sodium or ammonium, from the viewpoint of particle size control.

The linear alkyl benzene sulfonate is not particularly limited, but is preferably a compound represented by the formula (2) from the viewpoint of adsorptivity to aggregated particles and persistence to toner.
R ² -Ph-SO ₃ M ² (2)
In the formula, R ² represents a linear alkyl group, and is the same as the linear ^one of R ^{1 in} the formula (1). Ph is a phenyl group, and M ² is a monovalent cation. As the linear alkylbenzene sulfonate, sodium sulfate is preferably used.
The amount of the surfactant added is preferably from 0.1 to 15 parts by weight, more preferably from 0.1 to 15 parts by weight, based on 100 parts by weight of the resin constituting the aggregated particles, from the viewpoints of aggregation stopping properties and persistence to the toner. 1 to 10 parts by weight, more preferably 0.1 to 8 parts by weight.

In the coalescence process, the temperature in the system is preferably equal to or higher than the temperature in the system in the aggregation process, but the target toner particle size, particle size distribution, shape control, and particle fusing property In view of the above, the softening point of the binder resin is preferably −50 ° C. or higher and the softening point + 10 ° C. or lower, more preferably softening point −40 ° C. or higher and softening point + 10 ° C. or lower, softening point −30 ° C. or higher, The following is more preferable. The stirring speed is preferably a speed at which the aggregated particles do not settle.
The coalescence process can be performed simultaneously with the aggregation process, for example, by continuously raising the temperature or by raising the temperature to a temperature at which aggregation and coalescence can be performed and then continuing stirring at that temperature.
From the viewpoint of high image quality, the volume-median particle size of the coalesced particles is preferably 1 to 10 μm, more preferably 2 to 8 μm, and further preferably 3 to 7 μm.

Toner mother particles can be obtained by subjecting the obtained coalesced particles to a solid-liquid separation process such as filtration, a washing process, and a drying process as necessary.
In the washing step, for the purpose of ensuring sufficient charging characteristics and reliability as a toner, it is preferable to use an acid to remove metal ions on the surface of the toner base particles, and 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 base particles is preferably adjusted to 1.5% by weight or less, more preferably 1.0% by weight or less, from the viewpoint of chargeability.

Yellow toner The yellow toner obtained by the production method of the present invention contains the coalesced particles (toner base particles) obtained as described above. The content of the coalesced particles in the toner is From the viewpoint of chargeability and fixability, it is preferably 95 to 100% by weight, and more preferably 96.5 to 99% by weight.
Further, from the viewpoints of high image quality and productivity, the volume median particle size (D ₅₀ ) of the yellow toner particles is preferably 1 to 10 μm, more preferably 2 to 8 μm, and further preferably 3 to 7 μm.
The softening point of the yellow 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. Moreover, it is preferable that the maximum peak temperature of the endotherm by a differential scanning calorimeter is 60-140 degreeC from the same viewpoint, More preferably, it is 60-130 degreeC, More preferably, it is 0-120 degreeC.

In the yellow toner obtained by the production method of the present invention, an auxiliary agent such as a fluidizing agent can be added to the surface of the toner base particles as an external additive. 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 blending 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 base particles before processing with the external additive. However, when hydrophobic silica is used as an external additive, it is preferable to use 1 to 3 parts by weight of hydrophobic silica with respect to 100 parts by weight of toner base particles before processing with the external additive.

Examples of the transfer medium (recording material) to which the yellow toner of the present invention is applied include plain paper and OHP sheets used in electrophotographic copying machines and printers.
The toner for electrophotography obtained by the present invention can be used as a one-component developer or a two-component developer mixed with a carrier.

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

[Softening point and glass transition point of resin and toner]
(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. 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 The temperature was raised to 200 ° C. using a differential scanning calorimeter (Seiko Denshi Kogyo Co., Ltd., DSC210), and the sample cooled to 0 ° C. at a temperature lowering rate of 10 ° C./min from that temperature Measured in ° C / min. When a peak is observed at a temperature 20 ° C. or more lower than the softening point, the peak temperature is measured. When a peak is not observed at a temperature 20 ° C. or higher lower than the softening point, a step is observed. The temperature at the intersection of the tangent line indicating the maximum slope of the curve and the extension line of the base line on the high temperature side of the step is read as the glass transition point. The glass transition point is a physical property peculiar to the amorphous part of the resin, and is generally observed in amorphous polyester, but is observed when amorphous part exists even in crystalline polyester. There is.

[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 The resin is dissolved in chloroform 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 [manufactured by Sumitomo Electric Industries, Ltd., “FP-200”] to remove insoluble components to obtain a sample solution.
(2) Molecular weight distribution measurement Using the following apparatus, chloroform is flowed 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 used as standard samples.
Measuring device: CO-8010 (manufactured by Tosoh Corporation)
Analysis column: GMHLX + G3000HXL (manufactured by Tosoh Corporation)

[Particle size of resin emulsified particles and release agent emulsified particles]
Using a laser diffraction type particle size measuring instrument (HORIBA, “LA-920”), distilled water is added to the measurement cell, and the volume average particle size (D ₄ ) is measured at a concentration at which the absorbance is in an appropriate range.

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

[Agglomerated particles, coalesced particles and toner particle size]
Measuring machine: Coulter Multisizer II (Beckman Coulter, Inc.)
Aperture diameter: 50 μm
Analysis software: Coulter Multisizer AccuComp version 1.19
Cuckman Coulter)
Electrolyte: Isoton II (Beckman Coulter, Inc.)
Dispersion: Emulgen 109P (manufactured by Kao Corporation, polyoxyethylene lauryl ether, HLB: 13.6) is dissolved in the electrolytic solution to a concentration of 5% by weight to obtain a dispersion.
Dispersion condition: 10 mg of a measurement sample is added to 5 ml of the dispersion, and dispersed for 1 minute with an ultrasonic disperser, then 25 ml of an electrolyte is added, and further dispersed for 1 minute with an ultrasonic disperser. Prepare a dispersion.
Measurement conditions: By adding the sample dispersion to 100 ml of the electrolyte solution, the particle size of 30,000 particles is adjusted to a concentration that can be measured in 20 seconds, and then 30,000 particles are measured and the particle size distribution thereof. To determine the volume-median particle size (D ₅₀ ).
The particle size distribution is indicated by a CV value (standard deviation of particle size distribution / volume median particle size (D ₅₀ ) × 100).

Production Example 1 Production of polyester resin having acid group (polyester resin A) 8320 g of polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, polyoxyethylene (2.0) -2, 80 g of 2-bis (4-hydroxyphenyl) propane, 1592 g of terephthalic acid and 32 g of dibutyltin oxide (esterification catalyst) were reacted at 230 ° C. under normal pressure (101.3 kPa) for 5 hours under a nitrogen atmosphere, and further reacted under reduced pressure. I let you. 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 Production of polyester resin having acid group (polyester resin B) 17500 g of polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane, polyoxyethylene (2.0) -2, 16250 g of 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 were provided with a nitrogen introducing tube, a dehydrating tube, a stirrer and a thermocouple. It put into the one neck flask, it stirred at 220 degreeC under nitrogen atmosphere, and it was made to react until the softening point measured according to ASTM D36-86 reached 120 degreeC, and the polyester resin B was obtained. Polyester resin B had a softening point of 123 ° C., a glass transition temperature of 65 ° C., an acid value of 21.0 mgKOH / g, and a number average molecular weight of 2230.

Production Example 3 Production of Polyester Resin Having Acid Group (Polyester Resin C) Polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane (34090 g), fumaric acid (5800 g) and dibutyltin oxide (15 g) were nitrogenated. Place in a four-necked flask equipped with an introduction tube, dehydration tube, stirrer and thermocouple, stir at 230 ° C. under a nitrogen atmosphere, and react until the softening point measured according to ASTM D36-86 reaches 100 ° C. A polyester resin C was obtained. Polyester resin Resin C had a softening point of 98 ° C., a glass transition point of 56 ° C., an acid value of 22.4 mgKOH / g, and a number average molecular weight of 2930.

Production Example 4 Production of Masterbatch A 70 parts by weight of fine powder of polyester resin C of Production Example 3 and Pigment Yellow 93 slurry pigment (solid content: 47.5%) manufactured by Ciba Specialty Chemicals, so that the pigment content is 40 parts by weight The hensil mixer was charged and mixed for 5 minutes to wet. Next, this mixture was charged into a kneader mixer and gradually heated. The resin melted at approximately 90 to 110 ° C. and kneaded in a state where water was mixed, and kneading was continued at 90 to 110 ° C. for 20 minutes while water was evaporated.
Further, the kneading was continued at 120 ° C. to evaporate the remaining water, followed by dehydration drying. Further, kneading was continued at 120 to 130 ° C. for 10 minutes. After cooling, the mixture was kneaded with a heated three roll, cooled and coarsely crushed to obtain a crushed product (master batch A) of a highly concentrated colored composition containing a yellow pigment at a concentration of 40% by weight. When this was placed on a slide glass, heated and melted, and observed with a microscope, all pigment particles were finely dispersed, and no coarse particles were observed.

Production Example 5 Production of Master Batch B The pigment yellow 93 slurry pigment made by Ciba Specialty Chemicals was changed to the pigment pigment 185 slurry pigment (solid content 41.4%) made by BASF and produced in the same manner as in Production Example 4. A coarsely pulverized product (masterbatch B) of a highly concentrated colored composition containing a yellow pigment at a concentration of 30% by weight was obtained.

Production Example 6 Manufacture of Master Batch C Ciba Specialty Chemicals Pigment Yellow 93 slurry pigment was changed to Clariant Pigment Yellow 180 slurry pigment (solid content 46.9%). A coarsely pulverized product (master batch C) of a highly concentrated colored composition containing a yellow pigment at a concentration of 30% by weight was obtained.

Production Example 7 Production of Master Batch D The pigment pigment of Pigment Yellow 93 manufactured by Ciba Specialty Chemicals was changed to the pigment pigment of Pigment Yellow 151 (solid content: 46.7%) manufactured by Dainichi Seika Kogyo Co., Ltd. Thus, a coarsely pulverized product (masterbatch D) of a highly concentrated colored composition containing a yellow pigment at a concentration of 30% by weight was obtained.

Production Example 8 Production of Masterbatch E The pigment yellow 93 slurry pigment manufactured by Ciba Specialty Chemicals was changed to Pigment Yellow 17 slurry pigment (solid content: 46.9%) manufactured by Dainichi Seika Kogyo Co., Ltd. A coarsely pulverized product (masterbatch E) of a highly concentrated colored composition containing a yellow pigment at a concentration of 30% by weight was obtained.

Production Example 9 Production of Release Agent Emulsion A
In a 1 liter beaker, after dissolving 3.6 g of dipotassium alkenyl succinate aqueous solution “Latemul ASK (manufactured by Kao Corporation), effective concentration 28%” in 400 g of deionized water, carnauba wax (manufactured by Kato Yoko Co., Ltd.) , Melting point 85 ° C.) 100 g was dispersed. While maintaining the temperature at 90 to 95 ° C., the dispersion was subjected to a dispersion treatment with an Ultrasonic Homogenizer 600W (manufactured by Nippon Seiki Co., Ltd.) for 30 minutes to obtain a release agent emulsion A. The volume median particle size (D ₅₀ ) of the release agent particles in the obtained emulsion was 0.47 μm, the CV value was 26, and the solid content concentration was 22.7% by weight.

Example 1
(Preparation of resin emulsion A containing colorant (PY93))
In a 5 liter stainless steel kettle, 451 g of polyester resin A, 281 g of polyester resin B, 100 g of masterbatch A, and nonionic surfactant “Emulgen 430 (manufactured by Kao)” polyoxyethylene oleyl ether (HLB: 16.2) 8 g, anionic surfactant “Neopelex G-15 (manufactured by Kao)” 53 g of sodium dodecylbenzenesulfonate (solid content: 15% by weight), and potassium hydroxide aqueous solution (concentration: 5% by weight, pH) as a neutralizing agent 367 g of the value 14.1) was added and mixed at 95 ° C. with stirring at 250 r / min with a chi-type stirrer. The contents were stirred for 2 hours after reaching 95 ° C., and then 1520 g of deionized water was added at a dropping rate of 8 g / min with stirring at 200 r / min with a chi-type stirrer, and 200 mesh (aperture) was added. : 105 μm) through a wire mesh, a finely divided colorant-containing resin emulsion A was obtained. The pH value of the resin particles in the obtained resin emulsion is 6.4, the volume median particle size is 0.158 μm, the solid content concentration is 31.7% by weight, and what is the resin component on the wire mesh? Also did not remain.

(Preparation of yellow toner)
500 g of resin emulsion A, 37.5 g of release agent emulsion A, and 4.7 g of deionized water were placed in a 2 liter four-necked flask equipped with a dehydrating tube, a stirrer, and a thermocouple, and mixed at room temperature. Next, an aqueous solution prepared by dissolving 34.5 g of ammonium sulfate (special grade made by Sigma-Aldrich Japan) in 283.7 g of deionized water was added dropwise to the mixture over 10 minutes while stirring with a Kai-type stirrer. Thereafter, the mixed dispersion was heated to 55 ° C. over 3 hours to form aggregated particles. Thereafter, the mixture was kept at 55 ° C., and when the volume median particle size of the aggregated particles became 3.9 μm, a mixture of 50.5 g of resin emulsion A and 14.0 g of deionized water was added at 1.6 mL / Added dropwise in minutes and held at 55 ° C. for 20 minutes. Thereafter, a solution obtained by mixing 50.5 g of resin emulsion A and 14.0 g of deionized water and an aqueous solution obtained by dissolving 3.5 g of ammonium sulfate in 46.3 g of deionized water are separately dropped simultaneously at 1.6 mL / min. And then held at 55 ° C. for 20 minutes. After repeating this operation three more times, an aqueous solution obtained by diluting 42.3 g of an aqueous solution of polyoxyethylene (2 mol) sodium dodecyl ether sulfate (solid content: 28% by weight) with 381 g of deionized water was added to the Aggregated particles having a diameter (D ₅₀ ) of 4.9 μm were formed, and the temperature was raised to 80 ° C. After holding at 80 ° C. for 2 hours, it was cooled to room temperature. During this time, the toner shape changed from aggregated particles to coalesced particles. The volume-median particle size (D ₅₀ ) of the coalesced particles was 4.9 μm.

Subsequently, 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 5.2 μm, the CV value was 41.4, and the particle size distribution had a single peak.
1.0 part by weight of hydrophobic silica (manufactured by Wacker Chemie, TS530, number average primary particle size: 8 nm) is externally added to 100 parts by weight of the colored resin fine particle powder using a Henschel mixer to obtain a yellow toner. With the obtained yellow toner, a good image was obtained with a commercially available full color printer.

Comparative Example 1
The amount of the polyester resin, each surfactant, and the alkali is set as shown in Table 1, and the colorant-containing resin emulsion B is prepared in the same manner as in Example 1 except that the master batch A is changed to the master batch B. A yellow toner was prepared. The resin particles in the obtained resin emulsion had a volume median particle size of 0.312 μm, a solid content concentration of 30.8% by weight, and 15.8 g of the resin component remained on the wire mesh. Further, after the alkali was added, the hue changed and the color turned orange.

Comparative Example 2
Except for changing the master batch B to the master batch C, an attempt was made to produce the colorant-containing resin emulsion C and the yellow toner in the same manner as in Comparative Example 1, but most of the pigment and resin remained on the wire mesh. A colorant-containing resin emulsion could not be prepared.

Comparative Example 3
Except for changing the master batch B to the master batch D, an attempt was made to prepare the colorant-containing resin emulsion D and the yellow toner in the same manner as in Comparative Example 1, but most of the pigment and resin remained on the wire mesh. A colorant-containing resin emulsion could not be prepared.

Comparative Example 4
A colorant-containing resin emulsion E and a yellow toner were prepared in the same manner as in Comparative Example 1, except that the master batch B was changed to the master batch E. The resin particles in the obtained resin emulsion had a volume median particle size of 0.222 μm and a solid concentration of 32.0% by weight, and 1.8 g of the resin component remained on the wire mesh. Further, after the alkali was added, the hue changed and the color turned orange.

The results of the above examples and comparative examples are shown in Table 1 below. Moreover, each evaluation of alkali resistance, emulsification property, and aggregability was performed on the following reference | standard.

<Alkali resistance evaluation>
3: When the alkali is added, yellow hue change cannot be confirmed by visual evaluation.
2: At the time of alkali addition, although yellow hue change is slightly seen by visual evaluation, it is recognized as yellow.
1: At the time of alkali addition, yellow hue change can be confirmed by visual evaluation (red change), and it is recognized as orange.

<Emulsification>
3: After emulsification, when passing through a 200 mesh (mesh: 105 μm) wire mesh, no coarse particles remain on the wire mesh.
2: After emulsification, when passing through a 200 mesh (mesh: 105 μm) wire mesh, less than 2 g of coarse particles remain.
1: After emulsification, when passing through a 200 mesh (mesh: 105 μm) wire mesh, 2 g or more of coarse particles remain or cannot be emulsified.

<Cohesiveness>
2: Agglomerated particles having a single peak in particle size distribution and no coloring unevenness are formed.
1: The emulsification was not possible or the emulsified liquid turned red and the aggregation process was not reached.

  The method for producing a yellow toner of the present invention can control the toner particle size easily and in a short production time without substantially using an organic solvent, and also suppresses reddening. Can be suitably used for the production of yellow toners such as a method, an electrostatic recording method, and an electrostatic printing method.

Claims (6)

  (1) a binder resin containing at least a polyester having an acid group and C.I. I. Pigment Yellow 93 (Color Index Pigment Yellow 93) and (2) in an aqueous medium, C.I. I. A process for producing emulsified particles of the binder resin containing CI Pigment Yellow 93.   B. Resin in step (1) and C.I. I. The method for producing a yellow toner according to claim 1, wherein the use ratio of the pigment yellow 93 (binder resin / CI pigment yellow 93) is 90/10 to 97/3 by weight.   The method for producing a yellow toner according to claim 1 or 2, wherein the step (2) is performed at a temperature lower than the softening point of the binder resin.   The method for producing a yellow toner according to any one of claims 1 to 3, wherein in step (2), the pH value of the emulsion containing emulsified particles is 5.6 to 8.   The method for producing a yellow toner according to claim 1, further comprising a step of aggregating the emulsified particles in an aqueous medium.   A yellow toner obtained by the production method according to claim 1.