JP2016180892A - Production method of toner for electrostatic charge image development - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a production method of a toner for electrostatic charge image development, by which circularity of toner particles is promoted in an ageing step to improve solidification property, and thereby a toner excellent in environmental resistance can be obtained.SOLUTION: The production method of a toner for electrostatic charge image development includes: an emulsion polymerization step of polymerizing a monomer by an emulsion polymerization process to produce a dispersion containing polymer primary particles comprising a binder resin and wax; an aggregation step of aggregating the polymer primary particles and a colorant to produce a dispersion comprising particle aggregates; an ageing step of fusing the particle aggregates to produce a dispersion comprising toner base particles; and a cleaning and/or drying step of cleaning and/or drying the toner base particles. The ageing step includes a step of adding a solvent having a plasticizing effect on a resin component to the dispersion.SELECTED DRAWING: None

Description

  The present invention relates to a method for producing a toner for developing an electrostatic image used in an image forming apparatus such as an electrophotographic copying machine or printer.

  The electrostatic image developing toner is used in an image forming apparatus such as a printer, a copying machine, or a facsimile. The toner base particles of the electrostatic image developing toner are produced by a known method such as a pulverization method or a wet method. In particular, in order to satisfy demands such as high resolution and low-temperature fixing that have been demanded in recent years, it is produced by a wet method such as a suspension polymerization method, an emulsion polymerization aggregation method, or a dissolution suspension method.

In particular, in the emulsion polymerization aggregation method, the particle size, particle size distribution, and shape of the obtained toner can be controlled relatively easily.
As a method for producing a toner by the emulsion polymerization aggregation method, first, a raw material monomer, a polymerization initiator, an emulsifier and the like are mixed, and a wax or the like is added as a release agent and the particle size obtained by emulsion polymerization is 0.00. A dispersion containing polymer primary particles of about 05 μm to 0.5 μm is manufactured (emulsion polymerization step). Next, a colorant such as a pigment or a charge control agent is added to the dispersion to aggregate the polymer primary particles (aggregation step). Next, the aggregate obtained in the aggregation step is heated to fuse the respective components such as the polymer primary particles, the colorant, and the wax to obtain a dispersion containing toner mother particles (aging step). . Thereafter, the dispersion containing the toner base particles is cooled and solid-liquid separated to collect the toner base particles, washed as necessary, and dried to obtain toner base particles (solid-liquid separation, washing, Drying step). The toner base particles may be used as they are, but a known external additive may be added to the toner base particles in order to control fluidity and developability (addition step).

  For example, a low melting point wax is added as a raw material in order to satisfy, for example, a low-temperature fixing requirement required for the toner (Patent Document 1).

In the aging step, the distribution of the toner particles is sharp, and in order to obtain a high-quality toner, the temperature at which the polymer primary particles are fused is increased, the viscosity of the resin constituting the polymer primary particles is decreased, It is possible to promote circularization of the toner base particles.
However, if the viscosity of the resin constituting the polymer primary particles is lowered by increasing the heating temperature in the ripening step to promote circularization of the toner base particles, a low melting point such as wax on the toner base particle surface. Ingredients may ooze out, and toner base particles may aggregate in a twin shape, or may adhere more to the container, resulting in a decrease in yield.

JP 2004-251932 A

  The present invention has been made in view of the above circumstances, and promotes circularization in the ripening process and suppresses oozing of low melting point components such as wax on the surface of the toner base particles, thereby improving the caking property. It is an object of the present invention to provide a method for producing a toner for developing an electrostatic image capable of obtaining a toner having excellent environmental resistance.

The present invention pays attention to the emulsion polymerization aggregation method, and has found that the above-mentioned problems can be solved by adding a plasticizer in the aging step, and has completed the present invention.
[1] An emulsion polymerization step of producing a dispersion containing polymer primary particles containing a binder resin and a wax by polymerizing monomers by an emulsion polymerization method;
An aggregating step of aggregating the polymer primary particles and the colorant to produce a dispersion containing the particle aggregates;
An aging step of fusing the particle aggregate to produce a dispersion containing toner base particles;
A method for producing a toner for developing an electrostatic image comprising a washing and / or drying step for washing and / or drying the toner base particles,
The present invention relates to a method for producing a toner for developing an electrostatic charge image, wherein the aging step includes a step of adding a solvent having a plasticizing effect to a resin component to a dispersion.
[2] The present invention relates to a method for producing a toner for developing an electrostatic charge image, wherein 0.01 to 0.10 parts by mass of a solvent having a plasticizing effect on a resin component is added to 100 parts by mass of the binder resin.
[3] The present invention relates to a method for producing a toner for developing an electrostatic charge image, wherein the solvent having a plasticizing effect on the resin component has a boiling point of 60 to 100 ° C and an azeotropic point with water of 60 to 95 ° C.
[4] The present invention relates to a method for producing a toner for developing an electrostatic image, wherein an absolute value of a difference between a solubility parameter of a solvent having a plasticizing effect in the resin component and a solubility parameter of a binder resin is 3 or less.
[5] A solvent having a plasticizing effect on the resin component is selected from tetrahydrofuran, 1,4-dioxane, methyl ethyl ketone, a saturated aliphatic alcohol having 3 to 4 carbon atoms, 1,2-dimethoxyethane, acetonitrile, and pyridine. The present invention relates to a method for producing an electrostatic image developing toner, which is at least one selected from the group consisting of:
[6] The present invention relates to an electrostatic charge image developing toner obtained by any one of the production methods described above.

  According to the production method of the present invention, in the aging step of the emulsion polymerization aggregation method, by adding a solvent having a plasticizing effect to the resin component to the dispersion liquid, the heating temperature is compared without increasing the temperature. It is possible to obtain a toner base particle having a sharp particle distribution by promoting rounding in a short time, and to prevent the low-melting-point component such as wax from oozing into the toner base particle, thereby improving the caking property, It is possible to provide a method for producing a toner for developing an electrostatic image capable of obtaining a toner having excellent environmental resistance.

Hereinafter, embodiments of the present invention will be described. The method for producing a toner for developing an electrostatic charge image according to the present invention includes each step of producing toner base particles by an emulsion polymerization aggregation method, and a plasticizer is added in the aging step. The emulsion polymerization aggregation method includes the following steps.
<Emulsion polymerization process> The process of mixing the raw material containing a monomer and manufacturing the dispersion liquid containing a polymer primary particle by emulsion polymerization.
<Aggregating step> A step of adding a colorant to the dispersion obtained by the emulsion polymerization step to agglomerate the polymer primary particles to produce a dispersion containing the particle aggregate.
<Aging step> A step of producing toner base particles by fusing each component by heating the aggregate obtained in the aggregation step. In the embodiment of the present invention, the aging step includes a step of adding a solvent having a plasticizing effect to the resin component to the dispersion.
<Washing step> A step of washing the toner base particles.
<Drying step> A step of drying the washed toner base particles to produce toner particle powder.

<Emulsion polymerization process>
This is a step of mixing raw materials containing monomers and producing a dispersion containing polymer primary particles by emulsion polymerization.
In the emulsion polymerization step, a binder resin monomer (hereinafter sometimes referred to as a monomer) and a polymerization initiator are added to the “aqueous medium containing an emulsifier” in the reaction vessel, and the emulsion is simply put in an emulsified state. The polymer is polymerized to produce a polymer primary particle dispersion, which is subjected to an aggregation step. More specifically, in the emulsion polymerization method, at least one monomer, or an emulsion of the monomer, is supplied to an “aqueous medium containing an emulsifier” in a batch or continuous reaction vessel. The polymer is polymerized to produce polymer primary particles.

As the binder resin contained in the toner, resins conventionally used as the binder resin for toner can be used as appropriate.
The monomers constituting the binder resin may be added as the monomer, or the monomer may be added in the form of an emulsion. In order to obtain polymer primary particles having a narrow particle size distribution, it is preferable to add them to the polymerization apparatus in the form of a monomer emulsion. The emulsification of the monomers may be performed in a batch, or may be continuously emulsified and added to the polymerization apparatus.

  The conditions for the emulsion polymerization step are appropriately selected according to the monomers used, but the polymerization temperature is preferably 50 ° C. or higher, more preferably 70 ° C. or higher, and preferably 100 ° C. Below, it is 95 degrees C or less more preferably.

  The binder resin (including the monomer constituting the binder resin), water, and other components (polymerization initiator, chain transfer agent, crosslinking agent, wax) used in the emulsion polymerization step will be described below. .

[Binder resin]
As the binder resin contained in the toner, resins conventionally used as the binder resin for toner can be used as appropriate. For example, as a monomer, a polymerizable monomer having an acidic group (hereinafter sometimes simply referred to as an acidic monomer), a polymerizable monomer having a basic group (hereinafter simply referred to as a basic monomer) A polymerizable monomer having no acidic group or basic group (hereinafter, also referred to as other monomer) may be used. it can. Among these, it is preferable to use these monomers in combination.
The glass transition temperature of the binder resin is preferably 40 ° C. or higher, more preferably 45 ° C. or higher. Moreover, it is preferable that it is 80 degrees C or less, More preferably, it is 75 degrees C or less.

  Examples of the monomer having an acidic group include monomers having a carboxyl group such as acrylic acid, methacrylic acid, maleic acid, fumaric acid and cinnamic acid, monomers having a sulfonic acid group such as sulfonated styrene, and vinyl. Examples thereof include monomers having a sulfonamide group such as benzenesulfonamide, among which monomers having a carboxyl group are preferable, and acrylic acid or methacrylic acid is particularly preferable.

  Examples of the monomer having a basic group include aromatic vinyl compounds having an amino group such as aminostyrene, nitrogen-containing heterocycle-containing monomers such as vinylpyridine and vinylpyrrolidone, dimethylaminoethyl acrylate, and diethylaminoethyl methacrylate. Examples include (meth) acrylic acid esters having an amino group. The monomer having an acidic group and the monomer having a basic group may each exist as a salt with a counter ion.

The total amount of the monomer having an acidic group and the monomer having a basic group is preferably 0.01% by mass or more, more preferably 0.5% by mass or more, based on the total amount of monomers to be subjected to emulsion polymerization. In addition, the content is preferably 5% by mass or less, more preferably 3% by mass or less. Setting the total amount of the monomer having an acidic group and the monomer having a basic group in the above range is preferable because the particle size can be easily controlled. Furthermore, the content of the monomer having an acidic group in all monomers constituting the polymer primary particles is preferably 3% by mass or less, more preferably 2% by mass or less. Setting the content of the monomer having an acidic group within the above range is preferable because the particle size can be easily controlled.
Usually, when the amount of the monomer having an acidic group is large, the dispersion stability in water is good and the particle size controllability in the aggregation process is excellent, but conversely, the amount of the monomer having an acidic group is small. If it is too large, particle size control may be difficult.

  Other monomers include styrene such as styrene, methylstyrene, chlorostyrene, dichlorostyrene, pt-butylstyrene, pn-butylstyrene, pn-nonylstyrene; methyl acrylate, Ethyl acrylate, propyl acrylate, n-butyl acrylate, isobutyl acrylate, hydroxyethyl acrylate, ethyl hexyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, methacryl (Meth) acrylic acid esters such as hydroxyethyl acid and ethylhexyl methacrylate; acrylamide, N-propylacrylamide, N, N-dimethylacrylamide, N, N-dipropylacrylamide, N, N-dibutylacrylic And acrylic acid amides such as de like. Of these, styrene, butyl acrylate and the like are particularly preferable.

  Styrene is preferably used as the monomer used in the emulsion polymerization step. Further, it is preferable to use at least one selected from acrylic acid or alkyl ester of methacrylic acid as a copolymerization component in order to obtain a toner having a balanced performance.

〔water〕
The water is preferably pure water, and examples thereof include ion exchange water, distilled water, RO water passed through a reverse osmosis membrane, ultrapure water, and the like. Although the density | concentration of the water in a dispersion liquid is not specifically limited, 10 mass% or more is preferable with respect to the total mass of the dispersion liquid containing a polymer primary particle, and 40 mass% or less is preferable.

[Surfactant]
A surfactant may be used in the emulsion polymerization step. In the case of using a monomer having a self-emulsifying ability (for example, LATEMUL manufactured by Kao Corporation, rear soap manufactured by ADEKA Corporation, etc.), a surfactant is not essential.
The surfactant (emulsifier) is not particularly limited, and examples thereof include known surfactants such as cationic surfactants, anionic surfactants, and nonionic surfactants. Two or more of these surfactants may be used in combination. The amount of surfactant used in the continuous monomer emulsification may be constant, but may vary depending on the progress of polymerization.

Specific examples of the cationic surfactant used as a surfactant (emulsifier) in the emulsion polymerization step include dodecyl ammonium chloride, dodecyl ammonium bromide, dodecyl trimethyl ammonium bromide, dodecyl pyridinium chloride, dodecyl pyridinium bromide, hexadecyl trimethyl ammonium bromide, etc. Is mentioned.
Specific examples of the anionic surfactant include fatty acid soaps such as sodium stearate and sodium dodecanoate, sodium dodecyl sulfate, sodium dodecylbenzenesulfonate, and sodium lauryl sulfate.
Furthermore, specific examples of nonionic surfactants include polyoxyethylene dodecyl ether, polyoxyethylene hexadecyl ether, polyoxyethylene nonyl phenyl ether, polyoxyethylene lauryl ether, polyoxyethylene sorbitan monooleate ether, monodecanoyl sucrose, etc. Is mentioned.

  The amount of the surfactant used is appropriately selected according to the properties of the target toner, and is preferably 0.1 parts by weight or more with respect to 100 parts by weight of the monomer. 5 mass parts or less are preferable and 3 mass parts or less are more preferable. If it is in the said range, since it is excellent in stability of a polymer primary particle and it is easy to aggregate, it is preferable since it is easy to aggregate. When the amount used is larger than the above range, the latex is stable, but is not preferred because it is difficult to aggregate. On the other hand, when the amount used is less than the above range, there is a problem in the stability of the polymer primary particles, the cohesive force becomes too strong, and coarse powder is generated, which is not preferable.

(Polymerization initiator)
In the emulsion polymerization step, a polymerization initiator may be used as necessary. As the polymerization initiator, a known polymerization initiator (for example, a water-soluble polymerization initiator) can be used, and one or a combination of two or more polymerization initiators can be used. For example, hydrogen peroxide; persulfates such as potassium persulfate; organic peroxides such as benzoyl peroxide and lauroyl peroxide; 2,2′-azobisisobutyronitrile, 2,2′-azobis (2 , 4-dimethylvaleronitrile) and the like.
These polymerization initiators are combined with reducing agents such as reducing organic compounds such as ascorbic acid, tartaric acid and citric acid, and reducing inorganic compounds such as sodium thiosulfate, sodium bisulfite and sodium metabisulfite. It can also be a redox initiator. Of these, hydrogen peroxide, organic peroxides, and azo compounds are preferable as the initiator.

  The amount of the polymerization initiator used is appropriately selected according to the properties of the target toner. The polymerization initiator may be directly supplied to the batch reactor. It may be supplied together with a monomer and a surfactant, contained in the emulsion, and supplied to the reactor.

[Chain transfer agent]
In the emulsion polymerization step, a known chain transfer agent may be used as necessary. By using a chain transfer agent, it is possible to more precisely control the molecular weight and molecular weight distribution of the resin constituting the polymer primary particles, and a desired toner can be easily produced.
Specific examples of the chain transfer agent include t-dodecyl mercaptan, 2-mercaptoethanol, diisopropyl xanthogen, carbon tetrachloride, trichlorobromomethane and the like. The chain transfer agent may be used alone or in combination of two or more, and is preferably 5 parts by mass or less, more preferably 3 parts by mass or less with respect to 100 parts by mass of the monomer. Moreover, 0.01 mass part or more is preferable.

[Crosslinking agent]
In the emulsion polymerization step, a monomer having at least two functional groups (polyfunctional monomer) that acts as a cross-linking agent can be used as necessary.
Although it does not restrict | limit especially as a polyfunctional monomer, Usually, what has radical polymerizability is used. Examples include divinylbenzene, hexanediol diacrylate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, neopentyl glycol dimethacrylate, neopentyl glycol diacrylate, diallyl phthalate, and the like. It is also possible to use monomers having a reactive group as a pendant group, such as glycidyl methacrylate, methylol acrylamide, acrolein, and the like.

  The content in the case of using a polyfunctional monomer is preferably 0.005% by mass or more, more preferably 0.01% by mass or more, and still more preferably 100% by mass of all monomers constituting the polymer primary particles. Is 0.05% by mass or more, preferably 5% by mass or less, more preferably 3% by mass or less, and still more preferably 1% by mass or less.

〔wax〕
Wax can also be used in the emulsion polymerization step. When the wax is contained in the toner, the wax may be added in the emulsion polymerization step or may be added in the aggregation step described later. In order to contain the wax in the polymer primary particles, the wax is preferably added in the emulsion polymerization step.
When wax is used in the emulsion polymerization step, a method of performing polymerization in the presence of the wax can be mentioned. More specifically, wax fine particles obtained by emulsification in the presence of an emulsifier are added in the emulsion polymerization step, and the monomer is emulsion polymerized using the wax fine particles as a seed, or the wax is dissolved in the monomer. Examples thereof include a method of emulsion polymerization. Among these methods, a method of adding wax fine particles obtained by emulsifying wax together with a long-chain polymerizable monomer such as stearyl acrylate in the presence of an emulsifier in the emulsion polymerization step is particularly preferable. By adding the wax in the emulsion polymerization step by such a method, the dispersion of the wax in the toner becomes good, and a large amount can be added. As a result, the release property and filming resistance of the obtained toner may be improved.

  The wax is particularly large in size when used as a seed so as to be included in the polymer primary particles in the emulsion polymerization step, or when used as a co-aggregation when the polymer primary particles are aggregated in the aggregation step described later. Not limited. The wax preferably has a volume average diameter of 0.01 μm or more, more preferably 0.1 μm or more, preferably 3 μm or less, more preferably 2 μm or less, and particularly preferably 1.5 μm or less. The volume average diameter can be measured using a laser diffraction particle size distribution measuring device (for example, LA-500 manufactured by Horiba). When the volume average diameter of the wax is within the above range, it is easy to prepare a dispersion containing the polymer primary particles by adding it to the polymer primary particles in the emulsion polymerization step, and in the aggregation step. Particle size control becomes easy. When the volume average diameter of the wax is larger than 3 μm, it may be difficult to control the particle diameter during aggregation. Further, when the volume average diameter of the wax is smaller than 0.01 μm, it may be difficult to prepare a dispersion.

  As the wax, known waxes used for toner can be used. Specifically, olefin waxes such as low molecular weight polyethylene, low molecular weight polypropylene, and copolymer polyethylene; paraffin wax; ester waxes having a long-chain aliphatic group such as behenyl behenate, montanate ester, stearyl stearate; water Plant waxes such as soy castor oil and carnauba wax; ketones having long chain alkyl groups such as distearyl ketone; silicone waxes having alkyl groups; higher fatty acids such as stearic acid; long chain fatty alcohols such as eicosanol; glycerin, Examples include polyhydric alcohol carboxylic acid esters or partial esters obtained from polyhydric alcohols such as pentaerythritol and long chain fatty acids; higher fatty acid amides such as oleic acid amide and stearic acid amide; low molecular weight polyesters.

  The melting point of the wax is preferably 30 ° C. or higher, more preferably 40 ° C. or higher, and particularly preferably 50 ° C. or higher in order to further improve the toner fixability. Moreover, 100 degrees C or less is preferable and 90 degrees C or less is still more preferable. If the melting point is too low, the wax is exposed on the surface after fixing, and stickiness tends to occur. If the melting point is too high, the fixing property at low temperatures may be inferior.

  One type of wax may be used alone, or two or more types may be used in combination. The amount of wax used in the toner is not particularly limited, but is preferably 0.1% by mass or more, more preferably 1% by mass or more, particularly preferably 5% by mass or more, and most preferably 7%, based on the total mass of the toner. It is at least mass%, preferably at most 40 mass%, more preferably at most 35 mass%, particularly preferably at most 30 mass%.

[Polymer primary particles]
The volume average particle size of the polymer primary particles obtained in the emulsion polymerization step is appropriately selected according to the properties of the target toner, but is preferably 0.02 μm or more, more preferably 0.05 μm or more. More preferably, it is 0.1 μm or more. Moreover, 3 micrometers or less are preferable, 2 micrometers or less are more preferable, and 1 micrometer or less are further more preferable. The volume average diameter of the polymer primary particles can be controlled by the concentration of raw materials such as an emulsifier, a monomer and an initiator, polymerization conditions, and the like.

  The volume average diameter of the polymer primary particles can be measured by the method described in the examples described later. When the volume average diameter of the polymer primary particles is smaller than the above range, it may be difficult to control the aggregation rate. On the other hand, if it is larger than the above range, the particle size of the toner base particles obtained by agglomeration becomes too large, which may be inappropriate for applications requiring high resolution as a toner.

<Aggregation process>
In the aggregation step, the polymer primary particles obtained in the emulsion polymerization step, the colorant, and the charge control agent, wax, and other components used as necessary are aggregated to obtain a dispersion containing the particle aggregate. It is a manufacturing process. In the aggregating step, the agglomeration is performed up to almost the size of the toner particles prior to the aging step described later.
In the aggregation step, the polymer primary particles, the colorant, the charge control agent added as necessary, the wax, and other compounding components can be mixed simultaneously or sequentially. In addition, from the viewpoints of compositional uniformity and particle size uniformity, a dispersion of each component, that is, a polymer primary particle dispersion, a colorant dispersion, a charge control agent dispersion, and a wax fine particle dispersion is prepared in advance. It is preferable that these are mixed to form a mixed dispersion and then aggregated.
First, materials used in the aggregation process will be described in detail below.

[Colorant]
The colorant may be an inorganic pigment, an organic pigment, an organic dye, or a combination thereof. The colorant may be chromatic or achromatic.

  Specific examples of the colorant include carbon black as an achromatic colorant. Examples of the chromatic colorant include a cyan colorant, a yellow colorant, and a magenta colorant. Specifically, aniline blue, phthalocyanine blue, phthalocyanine green, Hansa yellow, rhodamine dyes, chrome yellow, quinacridone, benzidine yellow, rose bengal, triallylmethane dyes, monoazo dyes, disazo dyes, condensed azo dyes Any known dyes and pigments can be used alone or in combination.

In the case of a full color toner, yellow colorants include benzidine yellow, monoazo, and condensed azo dyes, magenta colorants include quinacridone, monoazo dyes, and cyan colorants include phthalocyanine blue. Are preferably used respectively.
Specifically, as the cyan colorant, C.I. I. Pigment Blue 15: 3, and yellow colorants include C.I. I. Pigment yellow 74, C.I. I. Pigment Yellow 93 and magenta colorants include C.I. I. Pigment red 238, C.I. I. Pigment red 269, C.I. I. Pigment red 57: 1, C.I. I. Pigment red 48: 2, C.I. I. Pigment Red 122 is particularly preferably used.

The colorant is preferably used in a state of being emulsified in water by a mechanical means such as a sand mill or a bead mill in the presence of an emulsifier, and more specifically, an organic pigment that is substantially insoluble in water is used as a surfactant. Finely dispersed in water in the presence of Under the present circumstances, it is good to add 10-15 mass parts of colorants and 1-15 mass parts of emulsifiers with respect to 100 mass parts of water. The volume average diameter of the colorant in the dispersant is preferably 0.01 μm or more, more preferably 0.05 μm or more, and preferably 3 μm or less, more preferably 1 μm.
Although the usage-amount of a coloring agent is not restrict | limited in particular, It is preferable to use it so that it may become 3 to 20 mass parts with respect to 100 mass parts of polymer primary particles.

(Charge control agent)
A charge control agent may be added to the toner in order to impart charge amount and charge stability. As the charge control agent, any known one can be used alone or in combination. For example, positively chargeable charge control agents include quaternary ammonium salts and basic / electron donating metal materials, and negatively chargeable charge control agents include metal chelates, metal salts of organic acids, and metal-containing metals. Examples thereof include dyes, nigrosine dyes, amide group-containing compounds, phenol compounds, naphthol compounds and their metal salts, urethane bond-containing compounds, and acidic or electron-withdrawing organic substances.

  In addition, when the toner for developing an electrostatic image obtained by the production method of the present invention is used as a toner other than a black toner in a color toner or a full color toner, a colorless or light-color charge control agent that does not impair the color tone of the toner is used. It is preferable to use it. For example, a quaternary ammonium salt compound is used as the positively chargeable charge control agent, and a metal salt of salicylic acid or alkylsalicylic acid with chromium, zinc, aluminum or the like, a metal complex, or a metal salt of benzylic acid as the negatively chargeable charge control agent. , Metal complexes, amide compounds, phenol compounds, naphthol compounds, phenolamide compounds, and hydroxynaphthalene compounds such as 4,4′-methylenebis [2- [N- (4-chlorophenyl) amido] -3-hydroxynaphthalene] are preferred.

In the present invention, when a charge control agent is contained in the toner by the emulsion polymerization aggregation method, the charge control agent is added together with a polymerizable monomer or the like at the time of emulsion polymerization, or the aggregation step is performed together with the polymer primary particles and the colorant. Or by adding the polymer primary particles and the colorant after agglomeration of the polymer primary particles and the colorant to a target particle size. Of these, it is preferable to disperse the charge control agent in water using a surfactant and add it to the aggregation step as a dispersion having a volume average diameter of 0.01 μm or more and 3 μm or less.
The amount of charge control agent used may be determined by the desired charge amount for the toner, but is usually preferably 0.01 parts by weight or more, more preferably 0.1 parts by weight with respect to 100 parts by weight of the polymer primary particles. It is above, Preferably it is 10 mass parts or less.

〔wax〕
Wax can be used for the toner to improve fixability. As the wax to be used, the wax described in the emulsion polymerization step can be used.

<Aggregation method>
Examples of the coagulation method include a method of heating in a stirring tank, a method of adding an electrolyte, or a method of combining them. When polymer primary particles are agglomerated under stirring, the particle size of the particle aggregate is controlled by the balance between the agglomeration force between the particles and the shearing force by agitation, but the aggregation force is adjusted by heating or adding an electrolyte. And it can be set as the target particle size.

As an electrolyte when aggregation is performed by adding an electrolyte, either an organic salt or an inorganic salt may be used. Specifically, inorganic salt having a monovalent metal cation such as NaCl, KCl, LiCl, Na ₂ SO ₄ , K ₂ SO ₄ , Li ₂ SO ₄ , CH ₃ COONa, C ₆ H ₅ SO ₃ Na; MgCl ₂ , inorganic salts having a divalent metal cation such as CaCl ₂ , MgSO ₄ , CaSO ₄ , ZnSO ₄ ; inorganic having a trivalent metal cation such as Al ₂ (SO ₄ ) ₃ , Fe ₂ (SO ₄ ) ₃ Examples include salts. By using the electrolyte, it becomes easy to control the average particle size and particle size distribution of the aggregated particles, the charge amount distribution of the obtained toner becomes sharp, and an image free from fogging can be obtained.

The amount of electrolyte added varies depending on the type of electrolyte, target particle size, etc., but is usually 0.05 parts by mass or more, preferably 0.1 parts by mass with respect to 100 parts by mass of the solid component of the mixed dispersion. In addition, it is usually 25 parts by mass or less, preferably 15 parts by mass or less, and more preferably 10 parts by mass or less. When the amount added is less than the above range, the progress of aggregation is delayed, and fine powder of 1 μm or less remains after the aggregation treatment, or the average particle diameter of the obtained particle aggregate does not reach the target particle diameter. May occur. In addition, when the addition amount is larger than the above range, aggregation is likely to proceed rapidly, making it difficult to control the particle size, and problems such as coarse particles and irregular shapes are included in the obtained particle aggregate. May occur.
The aggregation temperature in the case of performing aggregation by adding an electrolyte is preferably 20 ° C. or higher, more preferably 30 ° C. or higher, and preferably 70 ° C. or lower, more preferably 60 ° C. or lower.

  The aggregation temperature in the case of performing aggregation only by heating without using an electrolyte is preferably (Tg−20 ° C.) or more, more preferably, when the glass transition temperature of the binder resin contained in the polymer primary particles is “Tg”. Is (Tg-10 ° C) or more, preferably Tg or less, more preferably (Tg-5 ° C) or less. When the temperature is less than the range, the target particle size may not be reached, and when the temperature is over the range, it may be larger than the target particle size.

The time required for agglomeration is optimized by the shape of the apparatus and the processing scale, but in order to reach the target volume average diameter (Dv50), it is usually held at the above-mentioned predetermined temperature for at least 30 minutes or more. desirable. The temperature rise until reaching the predetermined temperature may be raised at a constant rate, or may be raised stepwise.
The volume average diameter (Dv50) of the particle aggregate obtained in this step is not particularly limited, but is preferably 3 μm or more, more preferably 4 μm or more, and preferably 9 μm or less, more preferably 8 μm or less.

<Aging process>
In the ripening step, the particle aggregate obtained in the aggregation step is heated to fuse the polymer primary particles and the colorant, the wax added if necessary, the charge control agent, and other components to each other. This is a step of forming a single particle (toner base particle).

The present invention is characterized in that in the aging step, a solvent having a plasticizing effect on the resin component is added to the dispersion. The solvent having a plasticizing effect on the resin component is preferably added at the same time as the start of the ripening step or within + 5 ° C. from the start of the ripening step (start of temperature increase). In the aging step, the resin component specifically refers to a resin component derived from the binder resin in the emulsion polymerization step.
In the aging step, by adding a solvent having a plasticizing effect to the resin component to the dispersion, the binder resin in the particle aggregate is easily melted, and the circularization is promoted. Toner mother particles having a circularity and a sharp particle distribution can be obtained. In addition, since toner base particles having a desired circularity can be obtained in a relatively short time, bleeding of the low melting point component such as wax to the toner base particle surface is suppressed, and the caking property is improved. A toner having excellent environmental resistance can be obtained.

The solvent having a plasticizing effect on the resin component is preferably 0.01 to 0.10 parts by mass, more preferably 0 with respect to 100 parts by mass in total of the monomers used when the polymer primary particles are produced. 0.02 to 0.06 parts by mass. When the addition amount of the plasticizer is within the above range, the binder resin in the particle aggregate is appropriately melted in the ripening step to promote circularization, and the time of the ripening step can be made shorter than before. In addition, it is possible to suppress the bleeding of low melting point components such as wax to the surface of the toner base particles, improve the caking property, and obtain a toner having excellent environmental resistance.
In addition, when the amount of the plasticizer is within the above range, the effect of promoting the rounding and suppressing the bleeding of the low melting point component, improving the caking property, and being excellent in environmental resistance is sufficiently exhibited. However, a toner that does not cause odor or volatile organic matter (VOC) problems can be manufactured by removing the plasticizer in the subsequent washing and drying steps.

The solvent having a plasticizing effect on the resin component preferably has a boiling point of 60 to 100 ° C and an azeotropic point with water of 60 to 95 ° C. More preferably, the solvent having a plasticizing effect on the resin component has a boiling point of 65 to 90 ° C and an azeotropic point with water of 60 to 85 ° C.
The solvent agent having a plasticizing effect on the resin component has a boiling point of 60 to 100 ° C. and an azeotropic point with water of 60 to 95 ° C., and the resin contained in the particle aggregate in the aging step Components, specifically the resin components derived from the binder resin, are melted to promote circularization and the aging process is shortened to prevent the low melting point component from oozing out on the surface of the toner base particles. It is possible to obtain a toner having improved caking properties and excellent environmental resistance, and it becomes easy to remove the plasticizer by a subsequent washing step and drying step.

The difference between the solubility parameter of the binder resin and the solubility parameter of the solvent having a plasticizing effect on the resin component preferably satisfies the following formula (1).
| (Solubility parameter of binder resin) − (Solubility parameter of solvent having plasticizing effect on resin component) | ≦ 3 (1)
If the difference between the solubility parameter of the binder resin and the solubility parameter of the solvent having a plasticizing effect on the resin component is within the range satisfying the formula (1), the resin component contained in the polymer primary particles in the aging step, specifically Specifically, the resin component derived from the binder resin can be melted to promote circularization and the aging process can be shortened, and it prevents the low-melting-point component such as wax from oozing into the toner base particles. Thus, it is possible to obtain a toner having improved caking properties and excellent environmental resistance.

  The solubility parameter in this specification is obtained by δ = √ ((ΔH−RT) / V) where δ is the solubility parameter, ΔH is the latent heat of vaporization of vapor, V is the molar volume, R is the gas constant, and T is the absolute temperature. The solubility parameter in this specification is based on the assumption that the force acting between the solvent and the solute is modeled as only the intermolecular force, and the interaction that causes the liquid molecules to aggregate is only the intermolecular force. And is defined by Hildebrand et al.

In the case of a solvent, the solubility parameter (δ) can be experimentally determined from this equation, but in the case of a polymer, since it does not volatilize, it is generally calculated using the Small equation: δ = d / MΣG (d: density, M : Molecular weight of polymer, G: constant specific to atomic group / group). Moreover, typical values of the main polymer by Hansen et al have been published as a list as shown in Table 1 (J.Brandrup, EHImmergut:. Polymer Handbook, 3 rd Ed, VII / 519~590).

Further, the difference between the solubility parameter of the wax contained in the polymer primary particles and / or the particle aggregate and the solubility parameter of the solvent having a plasticizing effect on the resin component preferably satisfies the following formula (2).
When a plurality of types of wax are contained in the polymer primary particles and / or particle aggregates, the solubility parameter of the wax having the largest solubility parameter among the plurality of types of wax and a solvent having a plasticizing effect on the resin component It is preferable that the difference from the solubility parameter satisfies the following formula (2).
| (Wax solubility parameter) − (Solubility parameter of solvent having plasticizing effect on resin component) |> 3 (2)
If the difference between the solubility parameter of the wax and the solubility parameter of the plasticizer contained in the polymer primary particles and / or particle aggregates is within the range satisfying the formula (2), the toner having a low melting point component such as wax in the aging step It is possible to obtain a toner that suppresses bleeding into the mother particles, improves the caking property, and has excellent environmental resistance.

The solvent having a plasticizing effect on the resin component added in the aging step can be appropriately selected depending on the type of the binder resin and the like, and is not particularly limited.
The solvent having a plasticizing effect on the resin component added in the aging step is preferably tetrahydrofuran, 1,4-dioxane, methyl ethyl ketone, a saturated aliphatic alcohol having 2 to 4 carbon atoms, 1,2-dimethoxyethane, acetonitrile. , Hexamethylphosphoric acid amide, and pyridine.

The temperature of the aging step is preferably not less than the glass transition temperature (Tg) of the binder resin contained in the polymer primary particles constituting the particle aggregate, more preferably not less than 5 ° C. higher than Tg, and preferably The temperature is 80 ° C. or higher than Tg, and more preferably 50 ° C. or lower than Tg.
The time required for the ripening step varies depending on the target shape, but after reaching the glass transition temperature of the binder resin contained in the primary polymer particles constituting the particle aggregate, usually 0.1 hour to 10 hours. It is desirable to hold for a time, preferably 1 to 6 hours.

  By heat treatment in the aging step, the polymer primary particles in the particle aggregate are fused and integrated with each other, and the particle aggregate has a shape close to a sphere. The particle aggregate before the aging step is considered to be an aggregate formed by electrostatic or physical aggregation using polymer primary particles as the main constituent. After the ripening step, the polymer primary particles constituting the particle aggregate are fused to each other, and toner mother particles having a nearly spherical shape can be obtained. According to such an aging process, by controlling the temperature and time of the aging process, the primary shape of the polymer primary particles is agglomerated, a potato type with advanced fusion, and a spherical shape with further fusion For example, toner base particles having various shapes (circularity) can be produced according to the purpose.

In the emulsion polymerization aggregation method, it is preferable to add a surfactant or raise the pH value of the aggregation liquid after the aggregation process, preferably before the aging process or during the aging process. As the surfactant used here, one or more surfactants can be selected and used from the surfactants that can be used when the polymer primary particles described above are produced. In particular, it is preferable to use the same surfactant as that used when producing the polymer primary particles.
Although the addition amount in the case of adding surfactant is not limited, Preferably it is 0.1 mass part or more with respect to 100 mass parts of solid components of a mixed dispersion liquid, More preferably, it is 1 mass part or more, More preferably, it is 3 masses. It is preferably 20 parts by mass or less, more preferably 15 parts by mass or less, and still more preferably 10 parts by mass or less.
After the aggregation process, before the completion of the ripening process, by adding a surfactant or increasing the pH value of the aggregation liquid, aggregation of particle aggregates aggregated in the aggregation process can be suppressed. In some cases, the generation of particles can be suppressed.

  The conditions for the aging step are appropriately selected in accordance with the plasticity used, etc., but the aging temperature is preferably 20 ° C. or higher, more preferably 30 ° C. or higher, and preferably 100 ° C. or lower. More preferably, it is 95 degrees C or less. The pressure in the container for performing the aging step depends on the volume in the container and the like, but is preferably 0.03 MPa or more, more preferably 0.04 MPa or more, and preferably 0.1 MPa or less, more preferably 0.00. It is 08 MPa or less. The aging time is usually 0.1 hour to 10 hours, preferably 1 hour to 6 hours. According to the production method of the present invention, the aging time can be shortened by adding a plasticizer in the aging step. More preferably 1 to 3 hours, and particularly preferably 1 to 2 hours.

<Cooling process>
The production method of the present invention may include a cooling step after the aging step and before the washing step. The cooling step is a step of cooling the dispersion of the toner base particles obtained in the ripening step to a temperature equal to or lower than the melting point of the wax contained in the toner and the glass transition temperature of the binder resin.

<Washing and / or drying process>
In the production method of the present invention, the toner base particles obtained through each step are subjected to solid-liquid separation according to a known method, and the toner base particles are collected, and then washed and / or dried as necessary. A process is provided.
In the washing step, for example, deionized water is used to wash with 100 times deionized water with respect to the total mass of the particle aggregate. As the conditions for the cleaning process, optimum conditions are appropriately selected according to the amount of the particle aggregates, but the atmospheric temperature in the cleaning process is usually room temperature. Here, room temperature is about 20 ° C. ± 5 ° C., specifically 15 to 25 ° C. The washing time is not particularly limited, but is usually 1 hour to 6 hours, preferably 2 hours to 4 hours.

The production method of the present invention includes a step of drying toner base particles obtained through a washing step as necessary.
Although the atmospheric temperature in a drying process is not specifically limited, Preferably it is 25 degreeC or more, More preferably, it is 30 degreeC or more, Preferably it is 55 degrees C or less, More preferably, it is 50 degrees C or less. The drying period is usually 0.1 to 6 hours, preferably 2 to 4 hours.

<External addition process>
In the method for producing a toner for developing an electrostatic charge image of the present invention, the toner base particles obtained in the above step may be used as they are, but in order to control fluidity and developability, a known external additive is added to the toner base particles. May be provided.

(External additive)
External additives include metal oxides and hydroxides such as alumina, silica, titania, zinc oxide, zirconium oxide, cerium oxide, talc and hydrotalcite, titanium such as calcium titanate, strontium titanate and barium titanate. Examples thereof include acid metal salts, nitrides such as titanium nitride and silicon nitride, carbides such as titanium carbide and silicon carbide, and organic particles such as acrylic resins and melamine resins. Among these, silica, titania, and alumina are preferable, and those that have been surface-treated with, for example, a silane coupling agent or silicone oil are more preferable. The average particle diameter is preferably 1 nm or more, more preferably 5 nm or more, and preferably 500 nm or less, more preferably 100 nm or less. It is also preferable to use a combination of a small particle size and a large particle size in the particle size range. The total amount of the external additive added is preferably 0.05 parts by mass or more, more preferably 0.1 parts by mass or more, and preferably 10 parts by mass or less, with respect to 100 parts by mass of the toner base particles. More preferably, it is 5 mass parts.

  As a method of adding an external additive to the surface of the toner base particles, for example, in a high-speed fluid mixer such as a Henschel mixer (manufactured by Mitsui Mining Co., Ltd.), the blade shape, the number of revolutions, the time, the number of driving and stopping, etc. Is appropriately set and stirred and mixed uniformly. It can also be fixed by a device capable of applying a compressive shear stress.

<Toner for electrostatic image development>
The toner for developing an electrostatic charge image obtained by the production method of the present invention has a volume average diameter of preferably 3 μm or more, more preferably 4 μm or more, and preferably 9 μm or less, more preferably 8 μm or less. The content ratio of fine particles having a volume average diameter of 5.04 μm or less is preferably 0.1% by volume or more, more preferably 0.5% by volume or more, and particularly preferably based on the total toner volume. 1% by volume or more. On the other hand, the upper limit is preferably 10% by volume or less, more preferably 7% by volume or less, and particularly preferably 5% by volume or less. The content ratio of coarse powder particles having a volume average diameter of 12.7 μm or more is preferably 2% by volume or less, more preferably 1% by volume or less, and particularly preferably 0.5% by volume or less with respect to the total toner volume. is there. It is most preferable that toner having a volume average diameter of 5.04 μm or less and toner having a volume average diameter of 12.7 μm or more, particularly coarse powder particles having a volume average diameter of 12.7 μm or more do not exist at all. Since it is difficult and equipment is required for the removal process, it is desirable to control within the above range. When the volume average diameter or the particle content ratio deviates from the above range, it may not be suitable for high-resolution image formation, and if it is less than the above range, it tends to be difficult to handle as a powder.

  Further, the ratio of the number average diameter (Dn50) to the volume average diameter (Dv50) (number average diameter (Dn50) / volume average diameter (Dv50) is preferably 1.25 or less, more preferably 1.20 or less, particularly preferably. The lower limit is preferably 1.0, and the lower limit of the electrostatic charge image developing toner has a sharp particle size distribution. It is preferable that the (number average diameter (Dn50) / volume average diameter (Dv50)) of the toner for developing an electrostatic charge image for achieving the above is in the above range. Is measured and defined by the method described in the examples.

  Further, the shape of the obtained toner for developing an electrostatic image is preferably as close to a sphere as possible, and the average circularity is preferably 0.90 or more, more preferably 0.92 or more, and particularly preferably 0.95 or more. The closer to a sphere, the less the localization of the charge amount in the particles and the development property tends to be uniform. However, since it is difficult to produce a perfect spherical toner, the average circularity is preferably Is 0.995 or less, more preferably 0.990 or less. The average circularity is defined as a value obtained by measuring by the method described in the examples and measuring the average circularity.

  The electrostatic charge image developing toner obtained by the production method of the present invention may be positively charged or negatively charged, but is preferably used as a negatively chargeable toner. Control of the chargeability of the toner can be adjusted by selection and content of the charge control agent, selection and addition amount of the external additive, and the like. The electrostatic image developing toner of the present invention can be suitably used for any of black toner, color toner, and full color toner.

  The toner for developing an electrostatic charge image obtained by the production method of the present invention is used for a magnetic two-component developer in which a carrier for conveying the toner to the electrostatic latent image portion by a magnetic force coexists, or magnetic powder in the toner. Although it may be used for either a magnetic one-component developer contained or a non-magnetic one-component developer that does not use magnetic powder as a developer, in order to express the effects of the present invention particularly, It is preferably used as a developer for a non-magnetic one-component development system.

  When used as a magnetic two-component developer, the carrier for mixing with the toner to form the developer is a known magnetic substance such as an iron powder type, ferrite type, or magnetite type carrier, or a resin coating on the surface thereof. Or a magnetic resin carrier can be used. As the carrier coating resin, generally known styrene resins, acrylic resins, styrene acrylic copolymer resins, silicone resins, modified silicone resins, fluorine resins, and the like can be used, but are not limited thereto. It is not a thing. The average diameter of the carrier is not particularly limited, but preferably has an average diameter of 10 μm to 200 μm. These carriers are preferably used in an amount of 5 to 100 parts by mass with respect to 1 part by mass of the toner.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples unless it exceeds the gist. In the following examples, “part” means “part by mass”. In addition, the live-action test was conducted by the following method.

  Each particle diameter, average circularity, electrical conductivity, time in each step, and the like were measured as follows.

<Measurement method and definition of volume average diameter and number average diameter of toner base particles>
As a pre-measurement treatment of the toner finally obtained through the external addition process, it was performed as follows. In a cylindrical polyethylene (PE) beaker having an inner diameter of 47 mm and a height of 51 mm, 0.100 g of toner using a spatula, 20% by weight DBS aqueous solution using a dropper (Daiichi Kogyo Seiyaku Co., Ltd., Neogen S-20A) 0.15 g was added. At this time, toner and a 20% DBS aqueous solution were added only to the bottom of the beaker so that the toner would not scatter on the edge of the beaker. Next, the mixture was stirred for 3 minutes using a spatula until the toner and 20% DBS aqueous solution became a paste. At this time, the toner was prevented from being scattered on the edge of the beaker.

  Subsequently, 30 g of dispersion medium Isoton II was added, and the mixture was stirred for 2 minutes using a spatula to obtain a uniform solution as a whole. Next, a fluororesin-coated rotor having a length of 31 mm and a diameter of 6 mm was placed in a beaker and dispersed using a stirrer at 400 rpm for 20 minutes. At this time, using a spatula at a rate of once every 3 minutes, macroscopic particles visually observed at the gas-liquid interface and the edge of the beaker were dropped into the beaker so as to form a uniform dispersion. Subsequently, this was filtered through a mesh having an opening of 63 μm, and the obtained filtrate was designated as “toner dispersion”.

Regarding the measurement of the particle diameter during the production process of the toner base particles, the filtrate obtained by filtering the agglomerated slurry with a 63 μm mesh was used as the “slurry liquid”.
The volume average diameter of the particles was Beckman Coulter's Multisizer III (aperture diameter 100 μm) (hereinafter abbreviated as “Multisizer”), the company's Isoton II was used as the dispersion medium, and the above “toner dispersion” Alternatively, the “slurry liquid” is diluted to a dispersoid concentration of 0.03% by mass, and the KD value is 118. Measured as 5. The measured particle size range is from 2.00 to 64.00 μm, and this range is discretized into 256 divisions at equal intervals on a logarithmic scale, and the toner calculated based on the statistical values on the basis of the volume is used. The volume average diameter of the mother particles was used. The number average diameter was calculated based on the statistical value on the basis of the number. A value obtained by dividing the volume average diameter of the toner base particles by the number average diameter was defined as a particle size distribution.

<Measurement method of volume average diameter less than 1 μm>
The volume average diameter of the particles having a volume average diameter of less than 1 μm was measured using a Nikkiso Co., Ltd. model Microtrac Nanotrac 150 (hereinafter abbreviated as “Nanotrack”) and company analysis software Microtrac Particle Analyzer Ver10.1.2-019EE. Measurement was performed by the method described in the instruction manual under the measurement conditions of 0.5 μS / cm of ion-exchanged water as a solvent, solvent refractive index: 1.333, measurement time: 600 seconds, and the number of measurements: one. Other setting conditions were particle refractive index: 1.59, transparency: transmission, shape: true sphere, density: 1.04.

<Measuring method and definition of average circularity>
The “average circularity” in the present invention is measured as follows and is defined as follows. That is, the toner base particles are dispersed in a dispersion medium (Isoton II, manufactured by Beckman Coulter, Inc.) so as to be in the range of 5720-7140 particles / μL, and a flow type particle image analyzer (Sysmex Corporation (formerly Toa Medical Electronics)). (Manufactured by FPIA 2100), measurement is performed under the following apparatus conditions, and the value is defined as “average circularity”. In the present invention, the same measurement is performed three times, and an arithmetic average value of three “average circularity” is adopted as the “average circularity”.
・ Mode: HPF
-HPF analysis amount: 0.35 μL
The number of HPF detected: 2000 to 2500 or less is measured by the device, and is automatically calculated and displayed in the device. The “circularity” is defined by the following equation.
[Circularity] = [Perimeter of a circle with the same area as the projected particle area] / [Perimeter of projected particle image]
And 2000-2500 which is the number of HPF detection is measured, and the arithmetic average (arithmetic mean) of the circularity of each individual particle is displayed on the apparatus as “average circularity”.

<Method of measuring electrical conductivity>
The electrical conductivity was measured using a conductivity meter (a personal SC meter model SC72 and a detector SC72SN-11 manufactured by Yokogawa Electric Corporation) according to an ordinary method according to the instruction manual.

<Measurement method and definition of temperature and reaction time in each process>
The temperature was measured in accordance with a conventional method using a platinum electrode made of SUS316 in the polymerization, and using a K-type thermocouple in the steps after the aggregation. In the polymerization, the reaction time is defined as the time from the monomer dropping start time to the cooling start time.

<Measuring method of glass transition temperature (Tg)>
Using a differential scanning calorimeter DSC 6220 manufactured by SII Nanotechnology, Inc., the temperature was measured at a rate of 10 ° C./min. The glass transition temperature was determined from the intersection of the extension line of the base line of the DSC curve and the tangent line showing the maximum inclination in the endothermic curve, using analysis software (EXSTAR6000 thermal analysis rheology system) attached to the apparatus. Instead of adopting the theoretical glass transition temperature as the glass transition temperature when the glass transition temperature cannot be clearly determined due to changes in the calorific value of other components other than resin, for example, wax, etc., a differential scanning calorimeter such as wax, etc. The measurement was performed on the resin prepared by removing the components that hinder the measurement.

<Measuring method of melting point>
Measure the melting point from the endothermic curve when the temperature was raised from 10 ° C to 110 ° C at a rate of 10 ° C / min by using the SSC5200 manufactured by Seiko Instruments Inc. did.

Example 1
<Preparation of Wax Dispersion _{A 1>}
Paraffin wax (Nippon Seiki HNP-9, melting point 75 ° C., solubility parameter 16 (MPa) ^1/2 ) 27 parts, stearyl acrylate (Tokyo Kasei Co., Ltd.) 2.8 parts, 20% sodium dodecylbenzenesulfonate aqueous solution (Daiichi Kogyo Seiyaku Co., Ltd., Neogen S20D) (hereinafter abbreviated as “20% DBS aqueous solution”) 1.9 parts and 68.3 parts of demineralized water were heated to 90 ° C. The mixture was stirred for 10 minutes using a Mark II f model manufactured by KK

  Next, this dispersion was heated to 90 ° C., and circulation emulsification was started under a pressure condition of 25 MPa using a homogenizer (manufactured by Gorin Co., Ltd., 15-M-8PA type). A wax dispersion A1 was prepared by dispersing until the average diameter (Mv) reached 250 nm.

<Preparation of polymer primary particle dispersion B ₁ (emulsion polymerization step)>
Stirrer (three blades), heating and cooling devices, concentrator, and a reactor equipped with a respective material-assisting agent charging device, 35.6 parts of a wax dispersion A _1, of deionized water were charged 259 parts of a stream of nitrogen The temperature was raised to 90 ° C.

  Thereafter, the mixture of the following monomers / emulsifier solution was added over 4 hours while stirring was continued. The time when the mixture of the monomers and the emulsifier aqueous solution was added dropwise was set as the polymerization start, and the following initiator aqueous solution 1 was added over 3.5 hours after 30 minutes from the start of the polymerization. Added over time. Thereafter, the inner temperature was maintained at 90 ° C. for 1 hour under stirring.

[Monomers]
Styrene (solubility parameter 19.0 (MPa) ^1/2 ) 76.8 parts butyl acrylate (solubility parameter 18.0 (MPa) ^1/2 ) 23.2 parts acrylic acid (solubility parameter 24.6 (MPa) ^{1 / 2} ) 1.5 parts trichlorobromomethane 1.0 part hexanediol diacrylate 0.7 part Based on the solubility parameters of these monomers, the solubility parameter of the binder resin is 17-19 (MPa) ^{1 / 2} .

[Emulsifier aqueous solution]
20% DBS aqueous solution 1.0 part demineralized water 67.1 parts

[Initiator aqueous solution 1]
8% aqueous hydrogen peroxide solution 15.5 parts 8% L (+)-ascorbic acid aqueous solution 15.5 parts

[Additional initiator aqueous solution 2]
8% L (+)-ascorbic acid aqueous solution 14.2 parts

  After completion of the polymerization reaction, the mixture was cooled to obtain a dispersion B1 containing milky white polymer primary particles. The volume average diameter (Mv) of the polymer primary particles was 275 nm, and the solid content concentration was 21.3% by mass. The peak top molecular weight (MP) of GPC was 31,000.

<Production of polymer primary particles Emulsion B _2>
A reactor equipped with a stirrer (three blades), a heating / cooling device, and each raw material / auxiliary charging device was charged with 1.72 parts of 20% DBS aqueous solution and 309 parts of ion-exchanged water while stirring under a nitrogen stream. The temperature was raised to 90 ° C. The following <Initiator aqueous solution 3> was added all at once.
Thereafter, the mixture of <polymerizable monomers etc.> and <emulsifier aqueous solution> described below was added over 5 hours while stirring was continued. Further, the time when the mixture was started to drop was set as “polymerization start”, and <initiator aqueous solution 4> was added over 6 hours from the start of polymerization in parallel with the above operation. Stirring was continued even after the addition of <Initiator aqueous solution 4> was completed, and the inner temperature was maintained at 90 ° C. for 1 hour.

[Polymerizable monomers, etc.]
Styrene 100.0 parts Acrylic acid 0.5 parts Trichlorobromomethane 0.63 parts
[Emulsifier aqueous solution]
20% DBS aqueous solution 1.0 part Ion-exchanged water 66.0 parts
[Initiator aqueous solution 3]
8% by mass aqueous hydrogen peroxide solution 3.2 parts 8% by mass L (+)-ascorbic acid aqueous solution 3.2 parts
[Initiator aqueous solution 4]
8% by mass aqueous hydrogen peroxide solution 18.9 parts 8% by mass L (+)-ascorbic acid aqueous solution 18.9 parts

Completion of the polymerization reaction after cooling to obtain a milky white polymer primary particle emulsion B _2. The volume average particle diameter (mv) measured using Microtrac UPA was 0.15 μm, and the solid content concentration was 19.7% by mass.

<Adjustment of colorant dispersion>
Quinacridone magenta PR122 aqueous dispersion (EP1610 Red, manufactured by Dainichi Seika Co., Ltd., solid content 20%), the average diameter measured by UPA was 150 nm.

<Production of particle aggregate (aggregation process)>
A mixer equipped with a stirrer (double helical blade), heating / cooling device, concentrating device, and each raw material / auxiliary charging device was charged with 90 parts (solid content) of the polymer primary particle dispersion B1 and the internal temperature was set to 10 ° C. Then, 0.1 part (solid content) of 20% DBS aqueous solution was added and mixed uniformly. Further, a 5% aqueous solution of ferrous sulfate (0.52 parts as FeSO ₄ .7H ₂ O) was added over 5 minutes, and stirring was continued for 5 minutes to mix uniformly. Subsequently, 5.0 parts (solid content) of a colorant dispersion was added over 5 minutes and mixed uniformly, and then 0.2 part of 0.5% aqueous aluminum sulfate solution (solid content) was added dropwise. During this time, the internal temperature was kept below 20 ° C. Thereafter, the temperature was raised to 53 ° C. over 75 minutes, and further raised to 56 ° C. over 150 minutes. Here, when the volume average particle diameter was measured using a multisizer, it was 6.1 μm. Then, it was kept 40 minutes the polymer primary particle dispersion B ₂ was added over 10 parts (solid content) 3 min. The volume average diameter (Dv50) of the particles at this time was 6.4 μm.

[Solvent with plasticizing effect on resin components]
Solvent 1: Tetrahydrofuran (hereinafter also referred to as “THF”. Boiling point 66 ° C., azeotropic point with water 63 ° C., solubility parameter 18.6 (Mpa) ^1/2 (total of styrene and butyl acrylate constituting the binder resin) 0.04 parts by mass with respect to 100 parts by mass)
Solvent 2: Substance name Methyl ethyl ketone (hereinafter also referred to as “MEK”. Boiling point 80 ° C., azeotropic point with water 73 ° C., solubility parameter 19.0 (Mpa) ^1/2 (styrene and butyl acrylate constituting the binder resin) 0.03 parts by mass with respect to 100 parts by mass in total)
Solvent 3: Substance name 1,2-dimethoxyethane (also referred to as dimethyl glycol, hereinafter referred to as “DMG”. Boiling point 84 ° C., azeotropic point with water 77 ° C., solubility parameter 17.6 (Mpa) ^1/2 (binding) (0.06 parts by mass with respect to 100 parts by mass in total of styrene and butyl acrylate constituting the resin)

The difference between the solubility parameter of the binder resin and the solubility parameter of the plasticizer was calculated as in the following formula (1-1). The results are shown in Table 2.
| (Solubility parameter of binder resin) − (Solubility parameter of solvent having plasticizing effect on resin component) | ≦ 3 (1-1)

Further, the difference between the solubility parameter having the largest numerical value among the waxes contained in the polymer primary particles and / or particle aggregates and the solubility parameter of the solvent having a plasticizing effect on the resin component is expressed by the following formula (2-1). As calculated. The results are shown in Table 2.
| (Wax solubility parameter) − (Solubility parameter of solvent having plasticizing effect on resin component) |> 2 (2-1)

<Manufacture of toner base particles C (aging process)>
Following the addition of B ₂ and holding for 40 minutes, 6 parts of 20% DBS aqueous solution (solid content) and 0.04 times the amount of desalted water of the total charge were added over 15 minutes. Immediately after the addition of demineralized water, tetrahydrofuran is added to the dispersion containing particle aggregates, and the temperature is raised to 98 ° C. over 75 minutes and held for each time (30 minutes, 60 minutes, 90 minutes). C _{1-1 to} C _1-3 were obtained.

Each slurry obtained by holding at 98 ° C. for each time was extracted and suction filtered with an aspirator using 5 types C (No. 5C manufactured by Toyo Roshi Kaisha, Ltd.) filter paper. The cake remaining on the filter paper is transferred to a stainless steel container with an internal volume of 10 L equipped with a stirrer (propeller blade), added with 8 kg of ion-exchanged water having an electric conductivity of 1 μS / cm, and uniformly dispersed by stirring at 50 rpm. Stirred for 30 minutes.
After that, it is again filtered by suction with 5 kinds C filter paper using an aspirator, and the solid matter remaining on the filter paper is again equipped with a stirrer (propeller blade), containing 8 kg of ion-exchanged water with an electric conductivity of 0.8 μS / cm. The sample was transferred to a stainless steel container having an internal volume of 10 L, and uniformly dispersed by stirring at 50 rpm, and the mixture was left stirring for 30 minutes. When this process was repeated 5 times, the electrical conductivity of the filtrate was 2 μS / cm.
The resulting cake was spread on a stainless steel vat to a height of 20 mm and dried in a blow dryer set at 40 ° C. for 48 hours to obtain a toner base obtained by holding at 98 ° C. for each time. Particles C _{1-1 to} C _1-3 were obtained.
Each toner mother particles C _1-1 -C _1-3 obtained, the volume average diameter of the toner mother particles was measured using a Multisizer III, the average circularity measured by a flow type particle analyzer, Table It is shown in 2.

<Production of toner for development _D 1-1 _{to D 1-3>}
To Kyoritsu Riko Co., Ltd. Sample Mill in KR-3, the toner mother particles _C 1-1 _{-C 1-3} were charged 100 parts, followed by silicone oil hydrophobized volume average primary particle size of 0.04μm Toner D for development by adding 0.5 parts of silica fine particles and 2.0 parts of silica fine particles having a volume average primary particle size of 0.012 μm hydrophobized with silicone oil, stirring, mixing, and sieving. _{1-1 to} D _1-3 were obtained.

(Example 2)
<Production of toner mother particles _{C 2>}
Toner base particles C were used in the same manner as in Example 1 except that methyl ethyl ketone was used in place of tetrahydrofuran and this plasticizer was added to a dispersion containing particle aggregates and held at 99 ° C. for 100 minutes. ₂ was obtained. Each toner mother particles C ₂ obtained, the volume average diameter as measured using a Multisizer III, the average circularity measured by a flow type particle analyzer, shown in Table 2.

<Production of toner for development _{D 2>}
Except for using the toner mother particles C ₂ is to obtain a developing toner D ₂ in the same manner as in Example 1.

Example 3
<Production of toner images mother particles _{C 3>}
The same procedure as in Example 1 was conducted except that 1,2-dimethoxyethane was used in place of tetrahydrofuran and the plasticizer was added to the dispersion containing the particle aggregate and maintained at 98 ° C. for 80 minutes. to obtain toner mother particles _{C 3.} Each toner mother particles C ₃ obtained, the volume average diameter as measured using a Multisizer III, the average circularity measured by a flow type particle analyzer, shown in Table 2.

<Production of toner for development _{D 3>}
Except for using the toner mother particles C ₃ got developed toner D ₃ in the same manner as in Example 1.

(Comparative Example 1)
<Production of toner mother particles _{C 4>}
In the step of producing toner base particles (ripening step), except that no plasticizer is added, the dispersion containing particle aggregates is heated at 102 ° C. under pressure so as not to boil, as in Example 1. The toner mother particles C _{4-1 to} C _4-3 were obtained by holding each time (60 minutes, 90 minutes, 130 minutes).

<Production of toner for development _{D 4>}
To obtain a developing toner _D 4-1 _{to D 4-3} at the same manner as in Example 1 except for using the toner mother particles _C 4-1 _{-C 4-3.}

  Using the developing toner, the caking property was evaluated as follows. The evaluation results are shown in Table 2.

<Caking property>
10 g of the obtained developing toner is placed in a test container in which paraffin paper is provided in a cylindrical shape along the inner peripheral surface of a SUS cylinder having an inner diameter of 2 cm, and a 20 g weight is placed on the developing toner in the test container. It was. The test container on which the weight was placed was placed in a constant temperature and humidity chamber at 25 ° C. and a humidity of 50, and this temperature and humidity were maintained and allowed to stand for 8 hours.
After standing for 8 hours, carefully remove the SUS cylinder of the test container, and then carefully remove the cylindrical paraffin paper. If the developing toner collapses when the cylindrical paraffin paper is removed, the caking property is reduced. 0 g.
If the developing toner seems to maintain a cylindrical shape after removing the paraffin paper, a weight of 20 g is placed, and the weight is increased in increments of 20 g, and the weight when the cylindrical developing toner collapses is consolidated. It was evaluated as (g). It can be said that the lower the numerical value of the caking property (g), the more the toner for development is not heat-sealed or moisture-absorbed, and the toner is excellent in environmental resistance.

  From the evaluation results in Table 2, in the aging step of the emulsion polymerization aggregation method, by adding a solvent having a plasticizing effect to the resin component to the dispersion, the heating temperature is relatively short without increasing the temperature. It is possible to obtain toner base particles with a sharp particle distribution by accelerating the rounding over time, suppressing the oozing of low melting point components such as wax to the toner base particles, improving the caking property, and environmental resistance A toner having excellent properties could be obtained.

Claims (6)

An emulsion polymerization step of producing a dispersion containing polymer primary particles containing a binder resin and wax by polymerizing monomers by an emulsion polymerization method;
An aggregating step of aggregating the polymer primary particles and the colorant to produce a dispersion containing the particle aggregates;
An aging step of fusing the particle aggregate to produce a dispersion containing toner base particles;
A method for producing a toner for developing an electrostatic image comprising a washing and / or drying step for washing and / or drying the toner base particles,
A method for producing a toner for developing an electrostatic charge image, comprising the step of adding a solvent having a plasticizing effect to a resin component to the dispersion in the aging step.   The method for producing a toner for developing an electrostatic charge image according to claim 1, wherein 0.01 to 0.10 parts by mass of a solvent having a plasticizing effect on the resin component is added to 100 parts by mass of the binder resin.   The method for producing a toner for developing an electrostatic charge image according to claim 1 or 2, wherein the solvent having a plasticizing effect on the resin component has a boiling point of 60 to 100 ° C and an azeotropic point with water of 60 to 95 ° C. .   The toner for developing an electrostatic charge image according to any one of claims 1 to 3, wherein an absolute value of a difference between a solubility parameter of the solvent having a plasticizing effect on the resin component and a solubility parameter of the binder resin is 3 or less. Manufacturing method.   The solvent having a plasticizing effect on the resin component is selected from the group consisting of tetrahydrofuran, 1,4-dioxane, methyl ethyl ketone, saturated aliphatic alcohol having 3 to 4 carbon atoms, 1,2-dimethoxyethane, acetonitrile, and pyridine. The method for producing a toner for developing an electrostatic charge image according to any one of claims 1 to 4, which is at least one selected.   An electrostatic charge image developing toner obtained by the production method according to claim 1.