JP7688565B2 - Toner manufacturing method - Google Patents

Description

The present invention relates to a method for producing toner.

Generally, electrophotography involves forming an electrostatic latent image on a photoconductive photoreceptor by various methods, then visualizing the latent image using toner, transferring the toner visible image to a transfer material such as paper, and fixing the toner image by applying heat or pressure. Various methods are known for these steps, and methods suitable for each image formation process are used.

One of the most common methods for producing toner is the pulverization method, which involves melting and mixing raw materials such as binder resin, colorant, release agent, and charge control agent, and then pulverizing and classifying them to obtain toner particles. This method has been widely adopted because it is relatively inexpensive and simple.
In recent years, in order to achieve high image quality by reducing the particle size of toner and narrowing the particle size distribution, research and development of polymerized toners manufactured by polymerization methods such as suspension polymerization, emulsion polymerization aggregation, and solution suspension methods has been actively carried out. Polymerized toners are easier to reduce in particle size and tend to have a sharp particle size distribution than pulverized toners.

In addition to promoting the miniaturization, high speed and high image quality of electrophotographic devices, there is a strong demand for improved low-temperature fixing properties of toner from the viewpoint of energy conservation, such as reducing the energy consumed in the fixing process.

Furthermore, recently, many types of paper are used as transfer materials, including recycled paper with large surface irregularities and coated paper with a smooth surface. To accommodate the surface properties of these transfer materials, fixing devices with a wide nip width, such as soft rollers and belt rollers, are preferably used. However, when the nip width is widened, the contact area between the toner and the fixing roller increases, making it easier for the so-called high-temperature offset phenomenon, in which molten toner adheres to the fixing roller, to occur, so hot offset resistance is required.

As one of the means for achieving the above, a technique of using a crystalline resin such as a crystalline polyester resin or a crystalline vinyl resin as a binder resin is known, and the crystalline vinyl resin is very suitable for the production of a water-based toner. For example, Patent Document 1 proposes a method for producing a toner obtained by polymerizing a monomer of an amorphous vinyl resin in the presence of a crystalline vinyl resin. In this way, by polymerizing an amorphous vinyl monomer in the presence of crystalline vinyl resin particles, the crystalline vinyl resin is finely dispersed in the amorphous vinyl resin, and a certain degree of low-temperature fixability can be achieved. However, if the ratio of the crystalline vinyl resin in the toner is small, the crystalline vinyl resin exists as a domain phase in the amorphous vinyl resin that becomes the matrix, and therefore the low-temperature fixability is still not sufficient.
As described above, there has been no method for producing a toner that has excellent low-temperature fixability while maintaining charge stability and hot offset resistance.

JP 2013-40982 A

The object of the present invention is to provide a method for producing a toner that has excellent charge stability, hot offset resistance, and low-temperature fixing properties.

The inventors have made the present invention as a result of intensive research. That is, the present invention is a method for producing a toner by agglomerating resin fine particles containing a resin composition (C) obtained by polymerizing a monomer composition (B0) in the presence of a crystalline vinyl resin (A), in which the crystalline vinyl resin (A) is a polymer of a monomer composition (A0) containing a monomer (a), the monomer (a) is a (meth)acrylate having 21 to 40 carbon atoms and a chain-like hydrocarbon group, the monomer composition (B0) contains 30% by weight or more of a styrene monomer based on the total weight of the monomer composition (B0), and the weight ratio [(A)/(B0)] of the crystalline vinyl resin (A) to the monomer composition (B0) before the reaction is 35/65 to 80/20.

The present invention makes it possible to provide a toner with excellent charge stability, hot offset resistance, and low-temperature fixing properties.

The present invention is a method for producing a toner, which comprises aggregating fine resin particles containing a resin composition (C) obtained by polymerizing a monomer composition (B0) in the presence of a crystalline vinyl resin (A).
The resin composition (C) is prepared by polymerizing the monomer composition (B0) in the presence of a polymer [crystalline vinyl resin (A)] of the monomer composition (A0) containing the monomer (a), which is a (meth)acrylate having 21 to 40 carbon atoms and a chain hydrocarbon group, at a weight ratio [(A)/(B0)] of 35/65 to 80/20. This makes it possible to obtain a toner having excellent low-temperature fixing property, hot offset resistance, and charging stability, as the amorphous vinyl resin, which is the polymer of the monomer composition (B0), is easily dispersed in the toner and has improved compatibility with the crystalline vinyl resin (A).

The toner obtained by the manufacturing method of the present invention contains crystalline vinyl resin (A) as an essential component.

The crystalline vinyl resin (A) is a polymer of a monomer composition (A0) containing a monomer (a), and is a crystalline vinyl resin. The monomer (a) is a (meth)acrylate having 21 to 40 carbon atoms and a chain hydrocarbon group. In the present invention, "(meth)acrylate" means acrylate and/or methacrylate. In the present invention, "crystalline" means that in the differential scanning calorimetry (also called DSC measurement) described below, the DSC curve has a peak top temperature of an endothermic peak.

The method for measuring the peak top temperature of the endothermic peak of the crystalline vinyl resin (A) is described below.
The measurement is performed using a differential scanning calorimeter {e.g., "DSCQ20" [manufactured by TA Instruments Co., Ltd.]}. The crystalline vinyl resin (A) is heated for the first time from 20°C to 150°C at 10°C/min, then cooled from 150°C to 0°C at 10°C/min, and then heated for the second time from 0°C to 150°C at 10°C/min. The temperature showing the top of the endothermic peak during the second heating process is taken as the peak top temperature of the endothermic peak of the crystalline vinyl resin (A).

The monomer (a) is a (meth)acrylate having a chain hydrocarbon group and carbon number of 21 to 40. The monomer (a) may be used alone or in combination of two or more kinds.
Examples of the monomer (a) include (meth)acrylates having a linear alkyl group (having 18 to 36 carbon atoms) [octadecyl (meth)acrylate (stearyl (meth)acrylate), nonadecyl (meth)acrylate, arachidyl (meth)acrylate (eicosyl (meth)acrylate), heneicosanyl (meth)acrylate, behenyl (meth)acrylate, lignoceryl (meth)acrylate, ceryl (meth)acrylate, montanyl (meth)acrylate, triacontyl (meth)acrylate (myrisyl (meth)acrylate), dodoriacontyl (meth)acrylate, and the like] and (meth)acrylates having a branched alkyl group (having 18 to 36 carbon atoms) [2-decyltetradecyl (meth)acrylate, and the like].
Among these, from the viewpoint of low-temperature fixing ability and charging stability, (meth)acrylates having a linear alkyl group (having 18 to 36 carbon atoms) are preferred, more preferably (meth)acrylates having a linear alkyl group (having 18 to 30 carbon atoms), still more preferably octadecyl (meth)acrylate, arachidyl (meth)acrylate, behenyl (meth)acrylate, lignoceryl (meth)acrylate, ceryl (meth)acrylate, and triacontyl (meth)acrylate, and particularly preferably octadecyl acrylate, arachidyl acrylate, behenyl acrylate, and lignoceryl acrylate.

The monomer composition (A0) containing the monomer (a) may be used in combination with other monomers as necessary, such as the nitrogen atom-containing monomer (b) and other monomers (d). The nitrogen atom-containing monomer (b) and other monomers (d) may be used alone or in combination of two or more.

Examples of the nitrogen atom-containing monomer (b) include a monomer (b1) having a nitrile group, a monomer (b2) having an amino group, and a monomer (b3) having an amide group.
Examples of the monomer (b1) having a nitrile group include (meth)acrylonitrile, cyanostyrene, cyanoacrylate, and a nitrile group-containing monomer in which the methyl group of methacrylonitrile is replaced with an alkyl group having 2 to 16 carbon atoms. In this specification, "(meth)acrylonitrile" means "acrylonitrile" and/or "methacrylonitrile".
Examples of the monomer (b2) having an amino group include aminoalkyl group-containing (meth)acrylates in which the alkyl group has 4 to 17 carbon atoms [aminoethyl (meth)acrylate, dimethylaminoethyl (meth)acrylate, diethylaminoethyl (meth)acrylate, t-butylaminoethyl methacrylate, etc.], N-aminoethyl (meth)acrylamide, (meth)allylamine, morpholinoethyl (meth)acrylate, 4-vinylpyridine, 2-vinylpyridine, crotylamine, N,N-dimethylaminostyrene, methyl α-acetaminoacrylate, vinylimidazole, N-vinylpyrrole, N-vinylthiopyrrolidone, N-arylphenylenediamine, aminocarbazole, aminothiazole, aminoindole, aminopyrrole, aminoimidazole, aminomercaptothiazole, and salts thereof.
Examples of the monomer (b3) having an amide group include (meth)acrylamide, N-methyl(meth)acrylamide, N-butylacrylamide, diacetone acrylamide, N-methylol(meth)acrylamide, N,N'-methylene-bis(meth)acrylamide, cinnamic acid amide, N,N-dimethylacrylamide, N,N-dibenzyl acrylamide, methacrylformamide, N-methyl N-vinyl acetamide, and N-vinyl pyrrolidone.

Among these, from the viewpoint of improving the hot offset resistance and charge stability of the toner, preferred is a monomer (b1) having a nitrile group, and more preferred is (meth)acrylonitrile.

Other monomers (d) include monomers other than monomers (a) and (b), such as styrene-based monomers (d1), (meth)acrylic monomers other than (a) (d2), vinyl ester monomers (d3), and aliphatic hydrocarbon vinyl monomers (d4).

Examples of the styrene-based monomer (d1) include styrene and alkylstyrenes having an alkyl group with 1 to 3 carbon atoms (eg, α-methylstyrene and p-methylstyrene).
Of these, styrene is preferred.

Examples of (meth)acrylic monomers (d2) include (meth)acrylic acid, alkyl (meth)acrylates in which the alkyl group has 1 to 17 carbon atoms [e.g., methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, lauryl (meth)acrylate, etc.], hydroxyalkyl (meth)acrylates in which the alkyl group has 1 to 17 carbon atoms [2-hydroxypropyl acrylate, 2-hydroxyethyl (meth)acrylate, and ethyl-2-(hydroxymethyl)acrylate], and esters of unsaturated carboxylic acids with 8 to 20 carbon atoms and polyhydric alcohols [ethylene glycol di(meth)acrylate, propylene glycol di(meth)acrylate, neopentyl glycol di(meth)acrylate, trimethylolpropane tri(meth)acrylate, 1,6-hexanediol di(meth)acrylate, and polyethylene glycol di(meth)acrylate, etc.].

Examples of vinyl ester monomers (d3) include aliphatic vinyl esters having 4 to 15 carbon atoms (e.g., vinyl acetate, vinyl propionate, isopropenyl acetate, etc.) and aromatic vinyl esters having 9 to 15 carbon atoms (e.g., methyl-4-vinyl benzoate, etc.).

Examples of the aliphatic hydrocarbon vinyl monomer (d4) include unsaturated aliphatic hydrocarbons having 2 to 20 carbon atoms [e.g., olefins (e.g., ethylene, propylene, butene, octene, etc.), dienes (e.g., butadiene, isoprene, 1,5-hexadiene, etc.)].

Among these, from the viewpoint of improving the hot offset property and charging stability of the toner, preferred are styrene-based monomer (d1) and (meth)acrylic monomer (d2), and more preferred is styrene-based monomer (d1).

From the viewpoint of improving the low-temperature fixing property and charging stability of the toner, the weight proportion of the monomer (a) in the monomer composition (A0) is preferably 15 to 93% by weight, more preferably 40 to 80% by weight, and even more preferably 45 to 80% by weight, based on the weight of the monomer composition (A0).

When the monomer composition (A0) contains the monomer (b), from the viewpoints of hot offset resistance and charging stability, the weight ratio of the monomer (b) in the monomer composition (A0) is preferably 5 to 30% by weight based on the weight of the monomer composition (A0).
It is preferable that the monomer composition (A0) contains a monomer (b1) having a nitrile group, and from the viewpoint of hot offset resistance and charging stability, it is more preferable that the weight ratio of the monomer (b1) having a nitrile group in the monomer composition (A0) is 5 to 30 wt % based on the weight of the monomer composition (A0).

When the monomer composition (A0) contains the monomer (d), from the viewpoints of hot offset resistance and charging stability, the weight ratio of the monomer (d) in the monomer composition (A0) is preferably 10 to 60% by weight, more preferably 10 to 40% by weight, based on the weight of the monomer composition (A0).
In the case where the monomer composition (A0) contains the styrene-based monomer (d1), from the viewpoints of hot offset resistance and charging stability, the weight ratio of the styrene-based monomer (d1) in the monomer composition (A0) is preferably 2 to 55% by weight, more preferably 5 to 40% by weight, based on the weight of the monomer composition (A0).

The crystalline vinyl resin (A) can be produced by polymerizing the monomer composition (A0) by a known method (e.g., radical polymerization, anionic polymerization, cationic polymerization, living radical polymerization, living anionic polymerization, living cationic polymerization, etc.). In the case of radical polymerization, for example, the resin can be synthesized by a solution polymerization method (e.g., JP-A-5-117330, etc.) in which the monomer is reacted with a radical reaction initiator (c) in a solvent (e.g., toluene). The radical reaction initiator (c) is not particularly limited, and examples thereof include inorganic peroxides (c1), organic peroxides (c2), and azo compounds (c3). These radical reaction initiators can also be used in combination.

Inorganic peroxides (c1) are not particularly limited, but examples include hydrogen peroxide, ammonium persulfate, potassium persulfate, and sodium persulfate.

The organic peroxide (c2) is not particularly limited, but examples thereof include benzoyl peroxide, di-t-butyl peroxide, t-butylcumyl peroxide, dicumyl peroxide, α,α-bis(t-butylperoxy)diisopropylbenzene, 2,5-dimethyl-2,5-bis(t-butylperoxy)hexane, di-t-hexyl peroxide, 2,5-dimethyl-2,5-di-t-butylperoxyhexyne-3, acetyl peroxide, isobutyryl peroxide, octanyl peroxide, decanolyl peroxide, lauroyl peroxide, oxide, 3,3,5-trimethylhexanoyl peroxide, m-toluyl peroxide, t-butyl hydroperoxide, t-butyl peroxy isobutyrate, t-butyl peroxy neodecanoate, cumyl peroxy neodecanoate, t-butyl peroxy-2-ethylhexanoate, t-butyl peroxy-3,5,5-trimethylhexanoate, t-butyl peroxy laurate, t-butyl peroxy benzoate, t-butyl peroxy isopropyl monocarbonate, and t-butyl peroxy acetate.

The azo compound (c3) is not particularly limited, but examples thereof include 2,2'-azobis-(2,4-dimethylvaleronitrile), 2,2'-azobisisobutyronitrile, 1,1'-azobis(cyclohexane-1-carbonitrile), 2,2'-azobis-4-methoxy-2,4-dimethylvaleronitrile, 2,2'-azobis(2-methylbutyronitrile), and azobisisobutyronitrile.

The amount of radical reaction initiator (c) used is not particularly limited, but is preferably 0.01 to 2% by weight based on the total weight of monomer composition (A0).

From the viewpoint of improving the performance (low-temperature fixing property and charge stability) of the toner, the peak top temperature (Tma) of the endothermic peak of the crystalline vinyl resin (A) is preferably 40 to 100° C. When Tma is 40° C. or higher, the charge stability of the toner can be improved, and when Tma is 100° C. or lower, the low-temperature fixing property of the toner can be improved.
The peak top temperature of the endothermic peak of the crystalline vinyl resin (A) is more preferably 45 to 95°C, further preferably 50 to 90°C, and particularly preferably 50 to 70°C.
The endothermic peak top temperature of the crystalline vinyl resin (A) can be adjusted by the type and composition ratio of the monomers constituting the crystalline vinyl resin (A) (for example, adjusting the carbon number of the monomer (a) constituting the crystalline vinyl resin (A) and adjusting the weight ratio of the monomer (a) constituting the crystalline vinyl resin (A)), weight average molecular weight, etc. For example, the endothermic peak top temperature of the crystalline vinyl resin (A) can be increased by increasing the carbon number of the monomer (a), increasing the weight ratio of the monomer (a), increasing the weight average molecular weight of the crystalline vinyl resin (A), etc.

The half width of the endothermic peak showing the peak top temperature of the crystalline vinyl resin (A) is preferably 6° C. or less from the viewpoints of low-temperature fixability and heat-resistant storage stability.
The half-width of the endothermic peak indicating the peak top temperature of the crystalline vinyl resin (A) is defined as the temperature width of the peak at half the height from the baseline of the endothermic peak to the maximum height of the peak, based on a DSC curve obtained by measuring the endothermic peak temperature.

The acid value of the crystalline vinyl resin (A) is preferably 60 mgKOH/g or less. When the acid value is 60 mgKOH/g or less, the peak top temperature Tm of the endothermic peak increases and the hygroscopicity decreases, resulting in good charging stability. The acid value of the crystalline vinyl resin (A) is more preferably 50 mgKOH/g or less, even more preferably 40 mgKOH/g or less, and particularly preferably 0 to 35 mgKOH/g.
The acid value of the crystalline vinyl resin (A) can be adjusted by the acid value of the monomer and the content of the monomer having an acid value. The acid value of (A) is measured, for example, by a method such as JIS K0070.

From the viewpoints of low-temperature fixing property, hot offset resistance, and fixing width, the weight-average molecular weight of the crystalline vinyl resin (A) measured by gel permeation chromatography (GPC) is preferably 2,000 to 200,000, more preferably 5,000 to 100,000, and even more preferably 15,000 to 60,000.

The number average molecular weight (hereinafter sometimes abbreviated as Mn) and weight average molecular weight (hereinafter sometimes abbreviated as Mw) of the crystalline vinyl resin (A) in the present invention can be measured using GPC under the following conditions.
Equipment (example): HLC-8120 [manufactured by Tosoh Corporation]
Column (example): 2 TSK GEL GMH6 columns [manufactured by Tosoh Corporation]
Measurement temperature: 40℃
Sample solution: 0.25% by weight THF solution Mobile phase: Tetrahydrofuran (containing no polymerization inhibitor)
Solution injection volume: 100μL
Detector: Refractive index detector Reference material: 12 standard polystyrenes (TSKstandard POLYSTYRENE) (molecular weight 500 1,050 2,800 5,970 9,100 18,100 37,900 96,400 190,000 355,000 1,090,000 2,890,000)
For the measurement of molecular weight, a sample is dissolved in THF to a concentration of 0.25% by weight, and the insoluble matter is filtered off using a PTFE filter having an aperture of 1 μm to obtain a sample solution.

The monomer composition (B0) used in the manufacturing method of the present invention is a monomer composition containing a styrene monomer, and is a monomer composition containing 30% by weight or more of the styrene monomer based on the total weight of the monomer composition (B0).

In addition to the styrene monomer, the monomer composition (B0) may contain other monomers as necessary. Examples of the other monomers include the styrene monomers (d1) other than styrene (e.g., alkylstyrenes having an alkyl group with 1 to 3 carbon atoms), the (meth)acrylic monomers (d2), the vinyl ester monomers (d3), the aliphatic hydrocarbon vinyl monomers (d4), and nitrogen atom-containing monomers (b) (monomers (b1) having a nitrile group, etc.). These monomers may be used alone or in combination of two or more.

From the viewpoint of low-temperature fixability, the monomers other than the styrene monomer contained in the monomer composition (B0) are preferably (meth)acrylic monomers (d2) and monomers having a nitrile group (b1), and more preferably methyl (meth)acrylate, ethyl (meth)acrylate, butyl (meth)acrylate, 2-ethylhexyl (meth)acrylate, (meth)acrylic acid, acrylonitrile and methacrylonitrile.

The weight proportion of the styrene monomer in the monomer composition (B0) is 30% by weight or more, preferably 50 to 90% by weight, and more preferably 60 to 80% by weight, based on the total weight of the monomer composition (B0), from the viewpoint of improving the charge stability of the toner.
The weight proportion of the monomer other than the styrene monomer in the monomer composition (B0) is 70% by weight or less, preferably 10 to 50% by weight, and more preferably 20 to 40% by weight, based on the total weight of the monomer composition (B0).
The total weight proportion of the (meth)acrylic monomer (d2) and the monomer (b1) having a nitrile group in the monomer composition (B0) is 70% by weight or less, preferably 10 to 50% by weight, and more preferably 20 to 40% by weight, based on the total weight of the monomer composition (B0).

The polymerization method for the resin composition (C) obtained by polymerizing the monomer composition (B0) in the presence of the crystalline vinyl resin (A) in the present invention is not particularly limited as long as it is a method for polymerizing the monomer composition (B0) in the presence of the crystalline vinyl resin (A), and examples of the polymerization method include the following methods.
Method (1): A method in which a dispersion (Dab) of resin fine particles (Da) of (A) is obtained, and then a monomer composition (B0) is added dropwise thereto while polymerizing.
Method (2): A method in which a melt of (A) is obtained, and then a monomer composition (B0) is added dropwise thereto while polymerizing.
Among the above methods, the polymerization method (2) is preferred because the polymers (A) and (B0) are easily converted into a homogeneous mixture, and a toner excellent in all of low-temperature fixing property, hot offset resistance, and charging stability is easily obtained.
When (B0) is polymerized in the presence of the crystalline vinyl resin (A), (B0) may react with the crystalline vinyl resin (A), but it is preferable that they do not react from the viewpoint of low-temperature fixability.

In the method (2), the method for mixing the monomer composition (B0) and the crystalline vinyl resin (A) may be a commonly used known method, and a solvent (toluene, xylene, ethyl acetate, tetrahydrofuran, methyl ethyl ketone, etc.) may be used as necessary.
The mixing apparatus includes a batch type mixing apparatus such as a reaction tank and a continuous type mixing apparatus. A batch type mixing apparatus is preferred because it is easy to adjust the pressure, such as by increasing or decreasing the pressure.

When polymerizing the monomer composition (B0) in the presence of the crystalline vinyl resin (A), the polymerization may be carried out under pressure. When polymerizing under pressure, the pressure is preferably 0.01 to 0.5 MPa, and more preferably 0.03 to 0.4 MPa.

From the viewpoints of obtaining a toner having excellent uniformity, excellent productivity, and good charge stability, the polymerization temperature in method (2) is preferably 110°C to 190°C. The polymerization temperature is preferably 120 to 190°C, more preferably 130 to 190°C, even more preferably 140 to 170°C, and particularly preferably 140 to 155°C. If the polymerization temperature is 190°C or lower, decomposition of the crystalline vinyl resin (A) is unlikely to occur, and good charge stability can be obtained. If the polymerization temperature is 110°C or higher, the viscosity of the crystalline vinyl resin (A) is low, and good uniformity between the crystalline vinyl (A) and the monomer composition (B0) can be obtained, making it possible to obtain a toner having even better uniformity.

When the monomer composition (B0) is polymerized in the presence of the crystalline vinyl resin (A), the weight ratio [(A)/(B0)] of the crystalline vinyl resin (A) to the monomer composition (B0) before the reaction is 35/65 to 80/20 from the viewpoints of low-temperature fixing property, charge stability, and hot offset resistance. When (A)/(B0) is 35/65 or more, the low-temperature fixing property is good, and when (A)/(B0) is 80/20 or less, the charge stability and hot offset resistance are good. (A)/(B0) is more preferably 35/65 to 70/30, and even more preferably 40/60 to 60/40.

The manufacturing process of the resin composition (C) obtained by polymerizing the monomer composition (B0) in the presence of the crystalline vinyl resin (A) may include other processes in addition to the polymerization process of polymerizing the monomer composition (B0) in the presence of the crystalline vinyl resin (A). The other processes are not particularly limited, and examples thereof include a process of reducing the pressure in the reaction system after the polymerization process in order to remove the organic solvent used in the polymerization process, initiator decomposition residues, etc. (reducing pressure process), and a process of pulverizing the resin composition (C) obtained by the polymerization process (pulverizing process).

The temperature of the decompression step is preferably 110 to 190°C, more preferably 130 to 190°C, and even more preferably 140 to 170°C.

The degree of pressure reduction in the pressure reduction step is preferably 0.01 to 30 kPa, more preferably 0.05 to 20 kPa, even more preferably 0.08 to 10 kPa, and particularly preferably 0.1 to 5 kPa, from the viewpoints of the charge stability, hot offset resistance, and productivity of the toner.

The resin composition (C) obtained by polymerizing the monomer composition (B0) in the presence of the crystalline vinyl resin (A) can contain, in addition to the crystalline vinyl resin (A) and the amorphous vinyl resin which is a polymer of the monomer composition (B0), a compound in which the polymer of the monomer composition (B0) is bonded to the crystalline vinyl resin (A) and a compound in which a part of the monomer composition (B0) is bonded to the crystalline vinyl resin (A), etc.

The glass transition temperature (Tg) of the resin composition (C) obtained by polymerizing the monomer composition (B0) in the presence of the crystalline vinyl resin (A) is preferably 25°C to 80°C, more preferably 40 to 65°C, from the viewpoint of the low-temperature fixing property and charge stability of the toner. When the Tg of the resin is 80°C or less, the low-temperature fixing property is good, and when the Tg is 25°C or more, the heat-resistant storage property is good. The glass transition temperature (Tg) of the resin composition (C) can be measured by the method specified in ASTM D3418-82 (DSC method) using, for example, DSCQ20 manufactured by TA Instruments Co., Ltd.

The resin composition (C) obtained by polymerizing the monomer composition (B0) in the presence of the crystalline vinyl resin (A) preferably has at least one endothermic peak top temperature (Tmb) in the range of 40 to 100°C. When (Tmb) is in this range, the toner has a good balance between low-temperature fixing property and charging stability. (Tmb) is preferably 43 to 95°C, more preferably 45 to 90°C, even more preferably 50 to 90°C, and particularly preferably 51 to 88°C. The endothermic peak top temperature (Tmb) can be measured by the same method as the endothermic peak top temperature (Tma) of the crystalline vinyl resin (A). In the present invention, the endothermic peak top temperature (Tmb) is preferably the endothermic peak peak top temperature derived from the crystalline vinyl resin (A).

From the viewpoints of low-temperature fixing property, hot offset property and charge stability, the resin composition (C) obtained by polymerizing the monomer composition (B0) in the presence of the crystalline vinyl resin (A) has an endothermic peak half-width indicating a peak top temperature (Tmb) of preferably 6°C or less, more preferably 5°C or less, and particularly preferably 2 to 5°C. The half-width of the endothermic peak indicating the peak top temperature (Tmb) is the temperature width of the peak at half the height from the baseline of the endothermic peak to the maximum peak height, based on the DSC curve obtained by measuring the peak top temperature (Tmb) of the endothermic peak.

From the viewpoint of excellent charge stability of the toner, the acid value of the resin composition (C) obtained by polymerizing the monomer composition (B0) in the presence of the crystalline vinyl resin (A) is preferably 40 mgKOH/g or less. When the acid value is 40 mgKOH/g or less, the peak top temperature Tmb of the endothermic peak increases and the hygroscopicity decreases, resulting in good charge stability. The acid value of the resin composition (C) is more preferably 30 mgKOH/g or less, and even more preferably 2 to 20 mgKOH/g. The acid value of the resin composition (C) can be adjusted by the acid value of the crystalline vinyl resin (A) and the acid value of the monomer contained in the monomer composition (B0), the content of the monomer having an acid value, etc. The acid value of the resin composition (C) is measured by a method such as JIS K0070.

The weight average molecular weight (Mw) of the resin composition (C) obtained by polymerizing the monomer composition (B0) in the presence of the crystalline vinyl resin (A) is preferably 5,000 to 200,000, more preferably 10,000 to 200,000, even more preferably 50,000 to 200,000, and particularly preferably 75,000 to 190,000, from the viewpoint of achieving both hot offset resistance and low-temperature fixing ability of the toner. The weight average molecular weight of the resin composition (C) can be measured by the same method and conditions as those for the crystalline vinyl resin (A).

The toner obtained by the manufacturing method of the present invention may contain, in addition to the resin composition (C) obtained by polymerizing the monomer composition (B0) in the presence of the crystalline vinyl resin (A), one or more known additives selected from colorants, release agents, charge control agents, and flow agents, etc., as necessary.

As the colorant, all of the dyes and pigments used as toner colorants can be used. For example, carbon black, iron black, Sudan Black SM, Fast Yellow G, Benzidine Yellow, Pigment Yellow, India Fast Orange, Irgasin Red, Paranitroaniline Red, Toluidine Red, Carmine FB, Pigment Orange R, Lake Red 2G, Rhodamine FB, Rhodamine B Lake, Methyl Violet B Lake, Phthalocyanine Blue, Pigment Blue, Brilliant Green, Phthalocyanine Green, Oil Yellow GG, Kayaset YG, Orazol Brown B, and Oil Pink OP can be mentioned, and the colorant may be a single one or a mixture of two or more kinds. In addition, if necessary, magnetic powder (powder of ferromagnetic metals such as iron, cobalt, and nickel, or compounds such as magnetite, hematite, and ferrite) can be contained to function as a colorant.
The content of the colorant is preferably 1 to 40 parts by weight, more preferably 3 to 10 parts by weight, based on 100 parts by weight of the resin composition (C). When a magnetic powder is used, the content is preferably 20 to 150 parts by weight, more preferably 40 to 120 parts by weight.

The release agent preferably has a flow softening point [T1 _/2 ] of 50 to 170°C as measured by a constant test force extrusion type capillary rheometer flow tester. Examples of the release agent include aliphatic hydrocarbon waxes such as polyolefin wax, microcrystalline wax, paraffin wax, and Fischer-Tropsch wax, as well as oxides thereof, carnauba wax, montan wax and deacidified waxes thereof, ester wax, fatty acid amides, fatty acids, higher alcohols, fatty acid metal salts, and mixtures thereof.

The method for measuring the flow softening point [T _1/2 ] will be described.
Using a constant test force extrusion-type capillary rheometer flow tester (e.g., CFT-500D, manufactured by Shimadzu Corporation), 1 g of a measurement sample is heated at a temperature increase rate of 6°C/min while applying a load of 1.96 MPa with the plunger and extruding it from a nozzle of 1 mm diameter and 1 mm length. A graph of "plunger depression amount (flow value)" vs. "temperature" is plotted, and the temperature corresponding to 1/2 of the maximum value of the plunger depression amount is taken as the flow softening point [T _1/2 ].

Examples of polyolefin waxes include (co)polymers of olefins (e.g., ethylene, propylene, 1-butene, isobutylene, 1-hexene, 1-dodecene, 1-octadecene, and mixtures thereof) [including those obtained by (co)polymerization and those obtained by further thermal degradation] (e.g., low molecular weight polypropylene, low molecular weight polyethylene, low molecular weight polypropylene-polyethylene copolymer), oxides of olefin (co)polymers with oxygen and/or ozone, maleic acid modified products of olefin (co)polymers [e.g., maleic acid and its derivatives (maleic anhydride, monomethyl maleate, monobutyl maleate, dimethyl maleate, etc.) modified products], copolymers of olefins and unsaturated carboxylic acids [(meth)acrylic acid, itaconic acid, maleic anhydride, etc.] and/or unsaturated carboxylic acid alkyl esters [(meth)acrylic acid alkyl esters (alkyl having 1 to 18 carbon atoms) and maleic acid alkyl esters (alkyl having 1 to 18 carbon atoms), etc.], etc.

Of the above, microcrystalline wax, paraffin wax, Fischer-Tropsch wax, carnauba wax and ester wax are preferred from the viewpoints of low-temperature fixability and hot offset resistance.

The charge control agent may be either a positively charged charge control agent or a negatively charged charge control agent, and examples of the charge control agent include nigrosine dyes, triphenylmethane dyes containing a tertiary amine as a side chain, quaternary ammonium salts, polyamine resins, imidazole derivatives, polymers containing quaternary ammonium bases, metal-containing azo dyes, copper phthalocyanine dyes, metal salts of salicylic acid, boron complexes of benzilic acid, polymers containing sulfonic acid groups, fluorine-containing polymers, and polymers containing halogen-substituted aromatic rings.

Examples of the fluidizing agent include silica, titania, alumina, calcium carbonate, fatty acid metal salts, silicone resin particles, and fluororesin particles, and two or more of them may be used in combination. From the viewpoint of the chargeability of the toner, silica is preferred. From the viewpoint of the transferability of the toner, the silica is preferably hydrophobic silica. From the viewpoint of the transferability of the toner, the silica is preferably hydrophobic silica.

The content of the resin composition (C) in the toner is preferably 30 to 97% by weight, more preferably 40 to 95% by weight, and further preferably 45 to 92% by weight, based on the weight of the toner.
The content of the colorant is preferably 0.05 to 60% by weight, more preferably 0.1 to 55% by weight, and even more preferably 0.5 to 50% by weight, based on the weight of the toner.
The content of the releasing agent is preferably 0 to 30% by weight, more preferably 0.5 to 20% by weight, and further preferably 1 to 10% by weight, based on the weight of the toner.
The content of the charge control agent is preferably 0 to 20% by weight, more preferably 0.1 to 10% by weight, and even more preferably 0.5 to 7.5% by weight, based on the weight of the toner.
The content of the fluidizing agent is preferably 0 to 10% by weight, more preferably 0 to 5% by weight, and even more preferably 0.1 to 4% by weight, based on the toner weight. The total content of the additives is preferably 3 to 70% by weight, more preferably 4 to 58% by weight, and even more preferably 5 to 50% by weight, based on the toner weight.

One or more known additives selected from colorants, release agents, charge control agents, and flow agents, which are used as needed, can be dispersed in a dispersion medium used in the step of obtaining resin fine particles and/or the step of aggregating resin fine particles described below to form an additive dispersion (colorant dispersion, release agent dispersion, etc.), and added in the step of obtaining resin fine particles and/or the step of aggregating resin fine particles, so that they can be contained in the toner obtained by the manufacturing method of the present invention. Note that a dispersant may be used in the additive dispersion as needed.

The manufacturing method of the present invention is a toner manufacturing method in which resin fine particles containing a resin composition (C) obtained by polymerizing a monomer composition (B0) in the presence of a crystalline vinyl resin (A) are aggregated, and includes a step of obtaining resin fine particles containing a resin composition (C) obtained by polymerizing a monomer composition (B0) in the presence of a crystalline vinyl resin (A) and a step of aggregating the resin fine particles (also referred to as an aggregation step).

The process of obtaining resin microparticles containing resin composition (C) obtained by polymerizing monomer composition (B0) in the presence of crystalline vinyl resin (A) and the process of aggregating the resin microparticles are described below.

The method for obtaining resin microparticles containing resin composition (C) obtained by polymerizing monomer composition (B0) in the presence of crystalline vinyl resin (A) is not particularly limited, but examples include the following [1] to [10].

[1] A method for producing a dispersion (Cab) of resin fine particles (Ca) by dispersing a resin composition (C) obtained by polymerizing a monomer composition (B0) in the presence of a crystalline vinyl resin (A) in an aqueous solvent, if necessary in the presence of a suitable dispersant.

[2] A method for producing a dispersion (Cab) of resin fine particles (Ca) by dispersing an organic solvent solution of a resin composition (C) obtained by polymerizing a monomer composition (B0) in the presence of a crystalline vinyl resin (A) in an aqueous solvent, if necessary in the presence of a suitable dispersant.

[3] A method for producing a dispersion (Cab) of resin fine particles (Ca) by dispersing an organic solvent solution of a resin composition (C) obtained by polymerizing a monomer composition (B0) in the presence of a crystalline vinyl resin (A) in an aqueous solvent, if necessary in the presence of a suitable dispersant, and then removing the organic solvent.

[4] A method in which a resin composition (C) obtained by polymerizing a monomer composition (B0) in the presence of a crystalline vinyl resin (A) is pulverized using a mechanical rotary or jet type fine grinder, then classified, and if necessary, dispersed in an aqueous solvent in the presence of a suitable dispersant to produce a dispersion (Cab) of resin fine particles (Ca).

[5] A method for producing a dispersion (Cab) of resin fine particles (Ca) by spraying a resin solution in an organic solvent in the form of a mist, in which the resin composition (C) obtained by polymerizing a monomer composition (B0) in the presence of a crystalline vinyl resin (A) is dissolved, and then dispersing the particles in an aqueous solvent, if necessary in the presence of a suitable dispersant.

[6] A method for producing a dispersion (Cab) of resin fine particles (Ca) by adding a poor solvent to a resin solution obtained by dissolving a resin composition (C) obtained by polymerizing a monomer composition (B0) in the presence of a crystalline vinyl resin (A) in an organic solvent, or by cooling a resin solution that has been previously heated and dissolved in an organic solvent, and then removing the organic solvent and dispersing the resulting particles in an aqueous solvent, if necessary, in the presence of a suitable dispersant.

[7] A method for producing a dispersion (Eab) of resin fine particles (Ea) by dispersing a crystalline vinyl resin (A) in an aqueous solvent, if necessary in the presence of a suitable dispersant, to produce a dispersion (Dab) of resin fine particles (Da), and then dropping a monomer composition (B0) into the dispersion (Dab) of resin fine particles (Da) and polymerizing it.

[8] A method for producing a dispersion (Eab) of resin fine particles (Ea) by dispersing an organic solvent solution of a crystalline vinyl resin (A) in an aqueous solvent, if necessary in the presence of a suitable dispersant, to produce a dispersion (Dab) of resin fine particles (Da), and then dropping a monomer composition (B0) into the dispersion (Dab) of resin fine particles (Da) and polymerizing it.

[9] A method for producing a dispersion (Eab) of resin fine particles (Ea) by dispersing an organic solvent solution of a crystalline vinyl resin (A) in an aqueous solvent, if necessary in the presence of a suitable dispersant, removing the organic solvent to produce a dispersion (Dab) of resin fine particles (Da), and then dropping a monomer composition (B0) into the dispersion (Dab) of resin fine particles (Da) and polymerizing it.

[10] A method for producing a dispersion (Dab) of resin fine particles (Da) by dispersing a monomer composition (A0) of a crystalline vinyl resin (A) in an aqueous solvent, if necessary in the presence of a suitable dispersant, and polymerizing the monomer composition (A0) and then producing a dispersion (Dab) of resin fine particles (Da), and then dropping a monomer composition (B0) into the dispersion (Dab) of resin fine particles (Da) and polymerizing the monomer composition (B0) to produce a dispersion (Eab) of resin fine particles (Ea).

Among the above methods [1] to [10], from the viewpoint of ease of production of the resin fine particles (Ca), methods [3] and [10] are preferred, and from the viewpoint of uniformity of the resin composition (C) obtained by polymerizing the monomer composition (B0) in the presence of the crystalline vinyl resin (A), method [3] is more preferred.

When an additive is used, a dispersion (Dab or Eab) of resin fine particles (Da or Ea) containing a resin composition (C) obtained by polymerizing a monomer composition (B0) in the presence of a crystalline vinyl resin (A) may be mixed with an additive dispersion (such as a colorant dispersion and a release agent dispersion) and used.

Examples of the dispersion medium constituting the dispersion liquids (Dab), (Eab) and the additive dispersion liquid include aqueous solvents.
As the aqueous solvent, any liquid containing water as an essential component can be used without limitation, and examples of the aqueous solvent that can be used include water, an aqueous solution of an organic solvent, an aqueous solution of a surfactant (s), an aqueous solution of a water-soluble polymer (t), and a mixture of two or more of these, as described below. In order to improve the dispersibility of the resin in the aqueous solvent, an organic solvent may be used to dissolve the resin.

Examples of the organic solvent include aromatic hydrocarbon solvents, aliphatic or alicyclic hydrocarbon solvents, halogenated solvents, ester or ester ether solvents, ether solvents, ketone solvents, alcohol solvents, amide solvents, sulfoxide solvents, heterocyclic compound solvents, and mixed solvents of two or more of these.
Specific examples of organic solvents include aromatic hydrocarbon solvents (toluene, xylene, ethylbenzene, tetralin, etc.); aliphatic or alicyclic hydrocarbon solvents (n-hexane, n-heptane, mineral spirits, cyclohexane, etc.); halogenated solvents such as methyl chloride, methyl bromide, methyl iodide, methylene dichloride, carbon tetrachloride, trichloroethylene, and perchloroethylene; ester or ester ether solvents such as ethyl acetate, butyl acetate, methoxybutyl acetate, methyl cellosolve acetate, and ethyl cellosolve acetate; diethyl ether, tetrahydrofuran, dioxane, ethyl cellosolve, butyl ether ... Examples of the organic solvent include ether solvents such as Rosolve and propylene glycol monomethyl ether; ketone solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, di-n-butyl ketone and cyclohexanone; alcohol solvents such as methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, t-butanol, 2-ethylhexyl alcohol and benzyl alcohol; amide solvents such as dimethylformamide and dimethylacetamide; sulfoxide solvents such as dimethylsulfoxide, heterocyclic compound solvents such as N-methylpyrrolidone, and mixed solvents of two or more of these. Among the above organic solvents, volatile ones having a boiling point of less than 100° C. are preferred. Preferred organic solvents include ethyl acetate, acetone and methyl ethyl ketone.

The amount of organic solvent used per 100 parts by weight of resin is preferably 0 to 300 parts by weight, more preferably 0 to 100 parts by weight, and even more preferably 25 to 70 parts by weight. When an organic solvent is used, it is preferable to remove the organic solvent by heating under normal or reduced pressure after obtaining the dispersion.

To improve the dispersibility of the resin in the aqueous solvent, a neutralizing agent may be used to neutralize the carboxyl groups of the resin. Examples of neutralizing agents include organic compounds such as ammonia and triethylamine, and inorganic compounds such as sodium hydroxide.

From the viewpoint of dispersibility, the amount of neutralizing agent used is preferably 1 to 150 mol %, more preferably 5 to 100 mol %, relative to the carboxyl groups of the resin.

When dispersing the resin in an aqueous solvent, a known surfactant (s) and inorganic dispersant can be used as an emulsifier or dispersant. The use of a surfactant (s) and an inorganic dispersant is preferred because it is easier to reduce the volume average particle size of the resin microparticles.

The surfactant (s) is not particularly limited, and examples thereof include anionic surfactants (s-1), cationic surfactants (s-2), amphoteric surfactants (s-3), and nonionic surfactants (s-4). The surfactant (s) may be a combination of two or more surfactants.

Examples of the anionic surfactant (s-1) include carboxylic acids or their salts, sulfate salts, carboxymethyl salts, sulfonates, and phosphate salts.
Examples of the cationic surfactant (s-2) include quaternary ammonium salt type surfactants and amine salt type surfactants.
Examples of the amphoteric surfactant (s-3) include carboxylate-type amphoteric surfactants, sulfate-type amphoteric surfactants, sulfonate-type amphoteric surfactants, and phosphate-type amphoteric surfactants.
Examples of the nonionic surfactant (s-4) include AO-addition type nonionic surfactants and polyhydric alcohol type nonionic surfactants.
Specific examples of these surfactants (s) include those described in JP-A-2002-284881.

The amount of surfactant (s) used per 100 parts by weight of water as the aqueous solvent is preferably 0 to 300 parts by weight, more preferably 0.001 to 10 parts by weight, and even more preferably 0.01 to 5 parts by weight.

Inorganic dispersants include polyvalent metal phosphates such as tricalcium phosphate, magnesium phosphate, aluminum phosphate, zinc phosphate, and hydroxyapatite; carbonates such as calcium carbonate and magnesium carbonate; inorganic salts such as calcium metasilicate, calcium sulfate, and barium sulfate; and inorganic compounds such as calcium hydroxide, magnesium hydroxide, and aluminum hydroxide.

The amount of inorganic dispersant used per 100 parts by weight of water as the aqueous solvent is preferably 0 to 300 parts by weight, more preferably 0.001 to 10 parts by weight.

When dispersing the resin in an aqueous solvent, a known water-soluble polymer (t) can be used as an emulsifier or dispersant. Using a water-soluble polymer (t) is preferable because it reduces the volume average particle size of the resin microparticles and tends to reduce the particle size distribution (volume average particle size/number average particle size).

Examples of the water-soluble polymer (t) include cellulose compounds (e.g., methyl cellulose, ethyl cellulose, hydroxyethyl cellulose, ethylhydroxyethyl cellulose, carboxymethyl cellulose, hydroxypropyl cellulose, and saponified products thereof, etc.), gelatin, starch, dextrin, gum arabic, chitin, chitosan, polyethylene glycol, etc.

The amount of water-soluble polymer (t) used per 100 parts by weight of water as the aqueous solvent is preferably 0 to 5 parts by weight.

The volume-based median diameter of the resin particles is preferably 0.050 to 1 μm, more preferably 0.07 to 0.5 μm, and even more preferably 0.09 to 0.3 μm, from the viewpoint of controlling the volume particle size and particle size distribution of the toner.
The volume-based median diameter of the resin fine particles can be measured using a dynamic light scattering particle size distribution measuring device "SZ-100" (manufactured by Horiba, Ltd.).

From the viewpoint of controlling the volumetric particle size and particle size distribution of the toner, the amount of resin fine particles in 100 parts by weight of the dispersion is preferably 1 to 70 parts by weight (solid content concentration of resin fine particles in the dispersion is 1 to 70% by weight), more preferably 5 to 65 parts by weight, and even more preferably 10 to 60 parts by weight.

The solid content concentration of the resin fine particles and the volatile content in the dispersion in the production method of the present invention were determined by the following methods.
Taking care not to cause precipitation of resin particles, etc., weigh out about 2.00 g of the sample before drying and dry it for 1 hour at 120° C. Remove the dried sample and measure its weight to two decimal places, calculate the solids concentration (wt%) from (weight of sample after drying/weight of sample before drying) x 100, and calculate the volatile content (wt%) from {(weight of sample before drying-weight of sample after drying)/weight of sample before drying} x 100.

The dispersion method in the above methods [1] to [10] is not particularly limited, but known equipment such as low-speed shear type, high-speed shear type, friction type, high-pressure jet type, and ultrasonic type can be applied. A high-speed shear type is preferred in order to make the particle size of the fine particles in the dispersion 0.05 to 1 μm. When a high-speed shear type disperser is used, the rotation speed is not particularly limited, but is generally 1000 to 30000 rpm, preferably 5000 to 20000 rpm. The dispersion time is not particularly limited, but in the case of a batch method, it is generally 0.1 to 5 minutes. The temperature is preferably 5 to 200° C., more preferably 20 to 100° C.
Examples of the dispersion device include batch-type emulsifiers such as Homogenizer (manufactured by IKA Corporation), Polytron (manufactured by Kinematica Corporation), and TK Auto Homo Mixer (manufactured by Tokushu Kika Kogyo Co., Ltd.), Ebara Milder (manufactured by Ebara Corporation), TK Filmix, TK Pipeline Homo Mixer (manufactured by Tokushu Kika Kogyo Co., Ltd.), Colloid Mill (manufactured by Kobe Steel Pantech Co., Ltd.), Ultra Visco Mill (manufactured by Imex Co., Ltd.), Slasher, and Trigonal Wet Fine Grinding Mill (manufactured by Nippon Coke Works Co., Ltd.), and Examples of such emulsifiers include continuous emulsifiers such as Ebara Microfluidizer (manufactured by Mizuho Kogyo Co., Ltd.), Capitron (manufactured by Eurotech Co., Ltd.), Fine Flow Mill (manufactured by Pacific Machinery Co., Ltd.), high pressure emulsifiers such as Microfluidizer (manufactured by Mizuho Kogyo Co., Ltd.), Nanomizer (manufactured by Nanomizer Co., Ltd.), APV Gaulin (manufactured by Gaulin Co., Ltd.), membrane emulsifiers such as Membrane Emulsifier (manufactured by Reika Kogyo Co., Ltd.), vibration type emulsifiers such as Vibro Mixer (manufactured by Reika Kogyo Co., Ltd.), ultrasonic emulsifiers such as Ultrasonic Homogenizer (manufactured by Branson Co., Ltd.), etc. Among these, from the viewpoint of particle size uniformity, APV Gaulin, homogenizer, TK Auto Homo Mixer, Ebara Milder, TK Filmix and TK Pipeline Homo Mixer are preferred.

The method for aggregating the resin microparticles obtained in the step of obtaining the resin microparticles is not particularly limited, and examples thereof include a method of heating a dispersion of resin microparticles obtained by the methods (1) to (10) placed in a tank equipped with a stirrer, a method of adding an aggregating agent without heating, and a method of combining heating and adding an aggregating agent.
When resin microparticles are aggregated under stirring to obtain aggregates of the desired size, the particle size of the aggregates is controlled by the balance between the cohesive force between the particles and the shear force caused by stirring, but the cohesive force can be increased by heating or adding an aggregating agent.

Examples of the flocculant include acids (hydrochloric acid, sulfuric acid, nitric acid, acetic acid, oxalic acid, etc.), metal salts of inorganic acids (sodium chloride, magnesium chloride, calcium chloride, aluminum chloride, aluminum sulfate, calcium sulfate, ammonium sulfate, aluminum nitrate, silver nitrate, copper sulfate, sodium carbonate, etc.), metal salts of fatty acids (sodium acetate, potassium formate, sodium oxalate, etc.), metal salts of aromatic fatty acids (sodium benzoate, sodium phthalate, potassium salicylate, etc.), metal salts of phenols (sodium phenolate, etc.), and amine salts (metal salts of amino acids, triethanolamine hydrochloride, aniline hydrochloride, etc.).
Of these, metal salts of inorganic acids and metal salts of fatty acids are preferred, and metal salts of inorganic acids are more preferred.

The temperature of the dispersion liquid placed in the tank when the resin fine particles are aggregated is preferably 5 to 100° C., more preferably 20 to 100° C., from the viewpoint of controlling the volume average particle size and particle size distribution of the toner.
In the step of forming the aggregates, the pH of the dispersion is preferably 2 to 10, more preferably 3 to 6, from the viewpoint of controlling the volume average particle size and particle size distribution of the toner.

From the viewpoint of controlling the volume average particle size and particle size distribution of the toner, the amount of the coagulant added is preferably 1 to 20 parts by weight, and more preferably 1 to 15 parts by weight, per 100 parts by weight of the resin microparticles.

When aggregation is carried out only by heating without using an aggregating agent, the aggregation temperature is preferably 40 to 100°C, more preferably 50 to 100°C.
The time required for aggregation is optimized depending on the shape of the apparatus and the processing scale, but in order for the toner particle size to reach the target particle size, it is desirable to maintain the above-mentioned predetermined temperature for at least 30 minutes or more. The temperature may be raised at a constant rate until the predetermined temperature is reached, or the temperature may be raised in stages.

In order to increase the stability of the aggregates obtained in the aggregation step, it is preferable to carry out an aging step after the aggregation step.
The aging process is a process in which the resin particles in the aggregate are fused together by heating or the like, and the toner shape becomes nearly spherical. The aggregate before the aging process is considered to be an assembly of the resin particles due to electrostatic or physical aggregation, but after the aging process, the resin particles constituting the aggregate are fused together, and the toner shape can be made nearly spherical. According to this type of aging process, by controlling the temperature and time of the aging process, it is possible to produce toners of various shapes according to the purpose, such as grape-shaped shapes in which the resin particles are aggregated, potato-shaped shapes in which the fusion has progressed, and spherical shapes in which the fusion has progressed further.

From the viewpoint of shape controllability of the resulting toner, the temperature when fusing the aggregates is preferably 5 to 200°C, and more preferably 30 to 100°C. The pH of the liquid when fusing the aggregates is preferably 3 to 10, and more preferably 5 to 10. The time required for the aging process differs depending on the shape of the desired toner base particles, but it is desirable to maintain the mixture at the above-mentioned specified temperature for 0.1 to 10 hours, and preferably 1 to 6 hours.

After the aggregation step, preferably before or during the aging step, it is preferable to add a surfactant or increase the pH value. The surfactant used here may be any known surfactant (s), but it is preferable to use the same surfactant (s) as that used when producing the resin microparticles. By adding a surfactant or increasing the pH value after the aggregation step and before the completion of the aging step, it is possible to suppress the aggregation of the aggregates that were aggregated in the aggregation step, and in some cases, it is possible to suppress the generation of coarse particles after the aging step.

The toner manufacturing method of the present invention preferably further includes a step of removing the aqueous solvent from the dispersion of aggregates obtained by the step of aggregating the resin fine particles, from the viewpoint of charging stability.

As a method for removing the aqueous solvent from the dispersion, the following methods [11] to [13] and combinations of two or more of these methods can be used.
[11] A method of drying the dispersion under reduced pressure or normal pressure.
[12] A method in which the dispersion is subjected to solid-liquid separation using a centrifuge, a sparkler filter and/or a filter press, and the solid-liquid separation is repeated by adding water or the like as necessary, and then the obtained solid is dried.
[13] A method of freezing and drying the dispersion (so-called freeze-drying).

In the above methods [11] and [12], drying can be performed using known equipment such as a fluidized bed dryer, a reduced pressure dryer, or a circulating air dryer. If necessary, classification can be performed using an air classifier or a sieve to obtain a predetermined particle size distribution.

From the viewpoints of chargeability, charge stability, toner fluidity and heat-resistant storage stability, the amount of remaining aqueous solvent per 100 parts by weight of toner is preferably 0 to 2 parts by weight, more preferably 0 to 1 part by weight, even more preferably 0 to 0.1 parts by weight, and particularly preferably 0 to 0.01 parts by weight.

From the viewpoints of low-temperature fixability and charge stability, the particle size of the toner obtained by the manufacturing method of the present invention is preferably 2 to 20 μm in volume average particle size, more preferably 3 to 15 μm, and even more preferably 4 to 8 μm. The number average particle size is preferably 2 to 20 μm, more preferably 3 to 15 μm, and even more preferably 4 to 8 μm. The particle size distribution (volume average particle size/number average particle size) is preferably 1.0 to 2.0, more preferably 1.0 to 1.8, and even more preferably 1.0 to 1.5. From the viewpoint of charge stability, a spherical shape is preferable. In addition, from the viewpoint of cleaning properties, it is preferable to control the fusion state and have moderate unevenness. The volume average particle size and number average particle size of the toner can be measured using a "Multisizer IV" (manufactured by Beckman Coulter, Inc.) or the like.

From the viewpoints of low-temperature fixing property, hot offset resistance, and charging stability, it is preferable that the toner obtained by the manufacturing method of the present invention has the amorphous vinyl resin dispersed as particles in the toner. In addition, the number-average particle diameter of the amorphous vinyl resin in the toner is preferably 0.02 to 0.5 μm, and more preferably 0.1 to 0.5 μm. The dispersion state and number-average particle diameter of the amorphous vinyl resin in the toner can be measured by dyeing the amorphous vinyl resin in the toner with ruthenium tetroxide, observing it with a transmission electron microscope (TEM), and performing image analysis using an image processing device (for example, Keyence's digital microscope VHX-700F).

From the viewpoint of chargeability, the acid value of the toner obtained by the manufacturing method of the present invention is preferably 5 to 20 mgKOH/g. The acid value of the toner can be adjusted by the acid value of the crystalline vinyl resin (A) or the resin composition (C). The acid value of the toner is measured, for example, by a method such as JIS K0070.

The toner obtained by the manufacturing method of the present invention is mixed with carrier particles such as iron powder, glass beads, nickel powder, ferrite, magnetite, and ferrite coated with resin (acrylic resin, silicone resin, etc.) as necessary and used as a developer for electric latent images. The weight ratio of toner to carrier particles is preferably 1/99 to 100/0. Alternatively, an electric latent image can be formed by rubbing against a member such as a charging blade instead of the carrier particles.

The toner obtained by the manufacturing method of the present invention is fixed to a support (paper, polyester film, etc.) by a copier, printer, etc. to form a recording material. As a method for fixing to a support, a known hot roll fixing method, flash fixing method, etc. can be used.

The toner obtained by the manufacturing method of the present invention can be preferably used for developing electrostatic images or magnetic latent images in electrophotography, electrostatic recording, electrostatic printing, etc. More preferably, it can be used for developing full-color electrostatic images or magnetic latent images.

The present invention will be described in detail below with reference to examples, but the present invention is not limited to these. In the following, "parts" refers to parts by weight unless otherwise specified.

<Production Example 1> [Synthesis of Crystalline Vinyl Resin (A-1)]
138 parts of xylene was charged into the autoclave, and after replacing with nitrogen, the temperature was raised to 170°C in a sealed state under stirring. A mixed solution of 450 parts of behenyl acrylate [manufactured by Nisshoku Techno Fine Chemical Co., Ltd., the same below], 150 parts of styrene [manufactured by Idemitsu Kosan Co., Ltd., the same below], 150 parts of acrylonitrile [manufactured by Nacalai Tesque Co., Ltd., the same below], 1.5 parts of di-t-butyl peroxide [Perbutyl D, manufactured by NOF Corp., the same below], and 100 parts of xylene was adjusted to 60°C, and while controlling the temperature inside the autoclave to 170°C, it was dropped over 3 hours to polymerize. After dropping, the dropping line was washed with 12 parts of xylene. After further maintaining at the same temperature for 0.5 hours, it was cooled to 70°C and the reaction rate of monomer (a) was confirmed. Since the reaction rate of the monomer (a) was less than 95%, the temperature was raised again to 170° C., 0.8 parts of di-t-butyl peroxide was added, and the reaction was continued until the reaction rate reached 95% or more. Thereafter, the solvent was removed at 170° C. under reduced pressure of 0.5 to 2.5 kPa for 5 hours to obtain a crystalline vinyl resin (A-1).

<Production Example 2> [Synthesis of Crystalline Vinyl Resin (A-2)]
An autoclave was charged with 600 parts of stearyl acrylate [manufactured by Kyoeisha Chemical Co., Ltd., the same applies below] and 150 parts of xylene, and substituted with nitrogen. After heating to 140°C in an open state with stirring, the temperature was raised to 170°C in a sealed state with stirring, and the temperature was controlled at 170°C for 2 hours. A mixed solution of 113 parts of styrene, 38 parts of acrylonitrile, 0.8 parts of di-t-butyl peroxide, and 93 parts of xylene was dropped over 2 hours while controlling the temperature inside the autoclave to 170°C, and polymerization was carried out. After dropping, the dropping line was washed with 7 parts of xylene. After further holding at the same temperature for 0.5 hours, the reaction rate of the monomer (a) was confirmed after cooling to 70°C, and was 95% or more, so the temperature was raised again to 170°C, and the solvent was removed for 5 hours under a reduced pressure of 0.5 to 2.5 kPa to obtain a crystalline vinyl resin (A-2).

<Production Example 3> [Synthesis of triacontyl acrylate]
In a reaction vessel equipped with a stirring device, a heating/cooling device, a thermometer, an air inlet tube, a pressure reducing device, and a water reducing device, 50 parts of 1-triacontanol [manufactured by Tokyo Chemical Industry Co., Ltd.], 50 parts of toluene, 12 parts of acrylic acid [manufactured by Mitsubishi Chemical Co., Ltd., the same below], and 0.05 parts of hydroquinone were added and stirred to make the mixture uniform. Then, 2 parts of paratoluenesulfonic acid were added, and the mixture was stirred for 30 minutes, and then the mixture was reacted for 5 hours while removing the water generated at 100 ° C. while blowing in air at a flow rate of 30 mL / min. Thereafter, the pressure in the reaction vessel was adjusted to 300 mmHg, and the reaction was continued for another 3 hours while removing the water generated. After cooling the reaction solution to room temperature, 30 parts of a 10 wt% aqueous sodium hydroxide solution was added, and the mixture was stirred for 1 hour, and then allowed to stand to separate the organic phase and the aqueous phase. The organic phase was collected by liquid separation and centrifugation, and 0.01 parts of hydroquinone was added, and the solvent was removed under reduced pressure while blowing in air to obtain triacontyl acrylate.

<Production Example 4> [Synthesis of crystalline vinyl resin (A-3)]
An autoclave was charged with 375 parts of triacontyl acrylate and 125 parts of xylene, and substituted with nitrogen. After heating to 140°C in an open state with stirring, the temperature was raised to 170°C in a sealed state with stirring, and the temperature was controlled at 170°C for 2 hours. A mixed solution of 173 parts of styrene, 75 parts of acrylonitrile, 128 parts of methyl acrylate [manufactured by Toagosei Co., Ltd., the same applies below], 3.0 parts of di-t-butyl peroxide, and 118 parts of xylene was dropped over 2 hours while controlling the temperature inside the autoclave to 170°C, and polymerization was carried out. After dropping, the dropping line was washed with 7 parts of xylene. After further holding at the same temperature for 0.5 hours, the reaction rate of the monomer (a) was confirmed after cooling to 70°C, and was 95% or more, so the temperature was raised again to 170°C, and the solvent was removed under a reduced pressure of 0.5 to 2.5 kPa for 5 hours to obtain a crystalline vinyl resin (A-3).

<Production Example 5> [Synthesis of Crystalline Vinyl Resin (A-4)]
An autoclave was charged with 260 parts of behenyl acrylate and 140 parts of xylene, and substituted with nitrogen. After heating to 140°C in an open state with stirring, the temperature was raised to 170°C in a sealed state with stirring, and the temperature was controlled at 170°C for 2 hours. A mixed solution of 234 parts of styrene, 130 parts of methyl acrylate, 26 parts of acrylic acid, 1.3 parts of di-t-butyl peroxide, and 203 parts of xylene was dropped over 1.5 hours while controlling the temperature inside the autoclave to 170°C, and polymerization was carried out. After dropping, the dropping line was washed with 7 parts of xylene. After further holding at the same temperature for 0.5 hours, the reaction rate of the monomer (a) was confirmed after cooling to 70°C, and was found to be 95% or more, so the temperature was raised again to 170°C, and the solvent was removed under a reduced pressure of 0.5 to 2.5 kPa for 5 hours to obtain a crystalline vinyl resin (A-4).

<Production Example 6> [Synthesis of Crystalline Vinyl Resin (A-5)]
An autoclave was charged with 455 parts of behenyl acrylate and 210 parts of xylene, and substituted with nitrogen. After heating to 140°C in an open state with stirring, the temperature was raised to 170°C in a sealed state with stirring, and the temperature was controlled at 170°C for 2 hours. A mixed solution of 33 parts of styrene, 98 parts of acrylonitrile, 65 parts of methyl acrylate, 2.6 parts of di-t-butyl peroxide, and 123 parts of xylene was dropped over 2.0 hours while controlling the temperature inside the autoclave to 170°C, and polymerization was carried out. After dropping, the dropping line was washed with 18 parts of xylene. After further holding at the same temperature for 0.5 hours, the reaction rate of the monomer (a) was confirmed after cooling to 70°C, and was 95% or more, so the temperature was raised again to 170°C, and the solvent was removed under a reduced pressure of 0.5 to 2.5 kPa for 5 hours to obtain a crystalline vinyl resin (A-5).

<Production Example 7> [Synthesis of crystalline vinyl resin (A-6)]
138 parts of xylene was charged into the autoclave, and after replacing with nitrogen, the temperature was raised to 170°C in a sealed state with stirring. A mixed solution of 450 parts of behenyl acrylate, 75 parts of styrene, 225 parts of acrylonitrile, 3.7 parts of di-t-butyl peroxide, and 100 parts of xylene was adjusted to 60°C, and while controlling the temperature inside the autoclave to 170°C, it was dropped over 3 hours to carry out polymerization. After dropping, the dropping line was washed with 12 parts of xylene. After further holding at the same temperature for 0.5 hours, it was cooled to 70°C and the reaction rate of monomer (a) was confirmed. Since the reaction rate of monomer (a) was less than 95%, the temperature was raised again to 170°C, and 2.0 parts of di-t-butyl peroxide was further added, and the reaction was carried out until the reaction rate was 95% or more. Thereafter, the solvent was removed at 170° C. under reduced pressure of 0.5 to 2.5 kPa for 5 hours to obtain a crystalline vinyl resin (A-6).

<Production Example 8> [Synthesis of crystalline vinyl resin (A-7)]
<Preparation of Aqueous Monomer Dispersion (D-1)>
Into a reaction vessel equipped with a stirrer, a heating/cooling device, a cooling tube, a thermometer, and a nitrogen inlet tube, 72 parts of behenyl acrylate, 24 parts of styrene, 24 parts of acrylonitrile, 3 parts of 1-dodecyl mercaptan [Kao Corporation: Thiokalcol 20], 0.6 parts of sodium alkylarylsulfosuccinate [Sanyo Chemical Industries, Ltd.: Eleminol JS-20], and 48 parts of ion-exchanged water were added, and the mixture was heated to 60° C. while stirring at a rotation speed of 300 rpm under a nitrogen stream, and emulsified by circulation in a high-pressure emulsifier to obtain an aqueous dispersion of a monomer (D-1). The volume-based median diameter of the obtained aqueous dispersion (D-1) was 0.25 μm, and the solid content concentration was 70% by weight.

<Production of Dispersion (Dab-1) of Crystalline Vinyl Resin (A-7) and Resin Fine Particles (Da-1)>
639 parts of ion-exchanged water and 0.6 parts of sodium alkylaryl sulfosuccinate were added to a reaction vessel equipped with a stirrer, a heating/cooling device, a cooling tube, a thermometer and a nitrogen inlet tube, and the temperature was raised to 70 ° C. while stirring under a nitrogen stream. After the temperature was raised, an aqueous dispersion of monomer (D-1), 4.6 parts of 10 wt% t-butyl hydroperoxide [Perbutyl H, manufactured by Nippon Oil & Fats Co., Ltd.], and 31.3 parts of 1 wt% aqueous ascorbic acid solution were added dropwise over 80 minutes. After the dropwise addition, 31.3 parts of 1 wt% aqueous ascorbic acid solution were further added dropwise over 10 minutes, and then the mixture was heated and stirred at 70 ° C. for 1 hour to obtain a dispersion (Dab-1) of resin fine particles (Da-1). The volume-based median diameter of the obtained crystalline vinyl resin fine particles (Da-1) was 0.23 μm, and the solid content concentration was 14 wt%. A part of the dispersion (Dab-1) was dried to obtain a crystalline vinyl resin (A-7).

<Production Example 9> [Synthesis of crystalline vinyl resin (A-8)]
138 parts of xylene was charged into the autoclave, and after replacing with nitrogen, the temperature was raised to 170°C in a sealed state under stirring. A mixed solution of 675 parts of behenyl acrylate [manufactured by Nisshoku Techno Fine Chemical Co., Ltd., the same below], 38 parts of styrene [manufactured by Idemitsu Kosan Co., Ltd., the same below], 38 parts of acrylonitrile [manufactured by Nacalai Tesque Co., Ltd., the same below], 1.5 parts of di-t-butyl peroxide [Perbutyl D, manufactured by NOF Corp., the same below], and 100 parts of xylene was adjusted to 60°C, and while controlling the temperature inside the autoclave to 170°C, it was dropped over 3 hours to polymerize. After dropping, the dropping line was washed with 12 parts of xylene. After further maintaining the same temperature for 0.5 hours, it was cooled to 70°C and the reaction rate of monomer (a) was confirmed. Since the reaction rate of the monomer (a) was less than 95%, the temperature was raised again to 170° C., 0.8 parts of di-t-butyl peroxide was added, and the reaction was continued until the reaction rate reached 95% or more. Thereafter, the solvent was removed at 170° C. under reduced pressure of 0.5 to 2.5 kPa for 5 hours to obtain a crystalline vinyl resin (A-8).

<Production Example 10> [Synthesis of Crystalline Vinyl Resin (A-9)]
An autoclave was charged with 130 parts of behenyl acrylate and 210 parts of xylene, and substituted with nitrogen. After heating to 140°C in an open state with stirring, the temperature was raised to 170°C in a sealed state with stirring, and the temperature was controlled at 170°C for 2 hours. A mixed solution of 254 parts of styrene, 98 parts of acrylonitrile, 169 parts of methyl acrylate, 2.6 parts of di-t-butyl peroxide, and 123 parts of xylene was dropped over 2.0 hours while controlling the temperature inside the autoclave to 170°C, and polymerization was carried out. After dropping, the dropping line was washed with 18 parts of xylene. After further holding at the same temperature for 0.5 hours, the reaction rate of the monomer (a) was confirmed after cooling to 70°C, and was 95% or more, so the temperature was raised again to 170°C, and the solvent was removed under a reduced pressure of 0.5 to 2.5 kPa for 5 hours to obtain a crystalline vinyl resin (A-9).

The compositions and physical properties of crystalline vinyl resins (A-1) to (A-9) are shown in Table 1.

<Production Example 11> [Production of Dispersion (Cab-1) of Resin Fine Particles (Ca-1)]
The autoclave was charged with 40 parts of crystalline vinyl resin (A-1) and substituted with nitrogen. After heating to 140°C in an open state under stirring, the autoclave was sealed under stirring. A mixed solution of 42.9 parts of styrene, 16.2 parts of butyl acrylate, 0.9 parts of acrylic acid, 0.09 parts of di-t-butyl peroxide, and 6.0 parts of xylene, which are components of amorphous vinyl resin as monomer composition (B0), was dropped over 3 hours while controlling the temperature inside the autoclave to 140°C to polymerize. After dropping, the dropping line was washed with 0.4 parts of xylene. After further holding at 140°C for 1 hour, the temperature was raised to 170°C over 1 hour to decompose the initiator. After cooling to 120°C, the reaction rate of styrene was confirmed to be 95% or more, so the temperature was raised again to 170°C and the solvent was removed for 5 hours under a reduced pressure of 0.5 to 2.5 kPa. The resultant was cooled to obtain a resin composition (C-1) in which the amorphous vinyl resin was dispersed in the crystalline vinyl resin (A-1).

In addition, 100 parts of resin composition (C-1) and 100 parts of methyl ethyl ketone were charged into another reaction vessel equipped with a stirrer, a heating/cooling device, a cooling tube, and a thermometer, and the mixture was stirred and homogenized to obtain an organic solvent solution, and the temperature was adjusted to 25°C. 2.2 parts of 10.0% by weight ammonia water were added as a neutralizing agent and stirred for 5 minutes. Then, 300 parts of 25°C ion-exchanged water were added dropwise over 1 hour to cause phase inversion emulsification, and methyl ethyl ketone was distilled off at 40°C under a reduced pressure of 30 kPa to obtain a dispersion (Cab-1) of resin fine particles (Ca-1). The volume-based median diameter of the resin fine particles (Ca-1) was 0.15 μm, and the solids concentration of the dispersion (Cab-1) was 20% by weight.

<Production Example 12> [Production of Dispersion (Cab-2) of Resin Fine Particles (Ca-2)]
The autoclave was charged with 40 parts of crystalline vinyl resin (A-2) and substituted with nitrogen. After heating to 140°C in an open state under stirring, the mixture was sealed under stirring. A mixed solution of 42.9 parts of styrene, 16.2 parts of butyl acrylate, 0.9 parts of acrylic acid, 0.09 parts of di-t-butyl peroxide, and 6.0 parts of xylene, which are components of amorphous vinyl resin as monomer composition (B0), was dropped over 3 hours while controlling the temperature inside the autoclave to 140°C to polymerize. After dropping, the dropping line was washed with 0.4 parts of xylene. After further holding at 140°C for 1 hour, the temperature was raised to 170°C over 1 hour to decompose the initiator. After cooling to 120°C, the reaction rate of styrene was confirmed to be 95% or more, so the temperature was raised again to 170°C and the solvent was removed for 5 hours under a reduced pressure of 0.5 to 2.5 kPa. The resultant was cooled to obtain a resin composition (C-2) in which the amorphous vinyl resin was dispersed in the crystalline vinyl resin (A-2).

In addition, 100 parts of resin composition (C-2) and 100 parts of methyl ethyl ketone were charged into another reaction vessel equipped with a stirrer, a heating/cooling device, a cooling tube, and a thermometer, and the mixture was stirred and homogenized to obtain an organic solvent solution, and the temperature was adjusted to 25°C. 2.2 parts of 10.0% by weight ammonia water were added as a neutralizing agent and stirred for 5 minutes. Then, 300 parts of 25°C ion-exchanged water were added dropwise over 1 hour to cause phase inversion emulsification, and methyl ethyl ketone was distilled off at 40°C under a reduced pressure of 30 kPa to obtain a dispersion (Cab-2) of resin fine particles (Ca-2). The volume-based median diameter of the resin fine particles (Ca-2) was 0.18 μm, and the solids concentration of the dispersion (Cab-2) was 20% by weight.

<Production Example 13> [Production of Dispersion (Cab-3) of Resin Fine Particles (Ca-3)]
The autoclave was charged with 40 parts of crystalline vinyl resin (A-3) and substituted with nitrogen. After heating to 140°C in an open state under stirring, the mixture was sealed under stirring. A mixed solution of 42.9 parts of styrene, 16.2 parts of butyl acrylate, 0.9 parts of acrylic acid, 0.09 parts of di-t-butyl peroxide, and 6.0 parts of xylene, which are components of amorphous vinyl resin as monomer composition (B0), was dropped over 3 hours while controlling the temperature inside the autoclave to 140°C to polymerize. After dropping, the dropping line was washed with 0.4 parts of xylene. After further holding at 140°C for 1 hour, the temperature was raised to 170°C over 1 hour to decompose the initiator. After cooling to 120°C, the reaction rate of styrene was confirmed to be 95% or more, so the temperature was raised again to 170°C and the solvent was removed for 5 hours under a reduced pressure of 0.5 to 2.5 kPa. The resultant was cooled to obtain a resin composition (C-3) in which the amorphous vinyl resin was dispersed in the crystalline vinyl resin (A-3).

In addition, 100 parts of resin composition (C-3) and 100 parts of methyl ethyl ketone were charged into another reaction vessel equipped with a stirrer, a heating/cooling device, a cooling tube, and a thermometer, and the mixture was stirred and homogenized to obtain an organic solvent solution, and the temperature was adjusted to 25°C. 2.2 parts of 10.0% by weight ammonia water were added as a neutralizing agent and stirred for 5 minutes. Then, 300 parts of 25°C ion-exchanged water were added dropwise over 1 hour to cause phase inversion emulsification, and methyl ethyl ketone was distilled off at 40°C under a reduced pressure of 30 kPa to obtain a dispersion (Cab-3) of resin fine particles (Ca-3). The volume-based median diameter of the resin fine particles (Ca-3) was 0.21 μm, and the solids concentration of the dispersion (Cab-3) was 20% by weight.

<Production Example 14> [Production of Dispersion (Cab-4) of Resin Fine Particles (Ca-4)]
13.3 parts of xylene and 40 parts of crystalline vinyl resin (A-4) were charged into the autoclave and replaced with nitrogen. After heating to 140°C in an open state under stirring, the mixture was sealed under stirring. A mixed solution of 42.9 parts of styrene, 16.2 parts of butyl acrylate, 0.9 parts of acrylic acid, 0.09 parts of di-t-butyl peroxide, and 19.0 parts of xylene, which are components of the amorphous vinyl resin as the monomer composition (B0), was dropped over 3 hours while controlling the temperature inside the autoclave to 140°C to polymerize. After dropping, the dropping line was washed with 1.0 part of xylene. After further holding at 140°C for 1 hour, the temperature was raised to 170°C over 1 hour to decompose the initiator. After cooling to 120°C, the reaction rate of styrene was confirmed to be 95% or more, so the temperature was raised again to 170°C and the solvent was removed for 5 hours under a reduced pressure of 0.5 to 2.5 kPa. The resultant was cooled to obtain a resin composition (C-4) in which the amorphous vinyl resin was dispersed in the crystalline vinyl resin (A-4).

In addition, 100 parts of resin composition (C-4) and 100 parts of methyl ethyl ketone were charged into another reaction vessel equipped with a stirrer, a heating/cooling device, a cooling tube, and a thermometer, and the mixture was stirred and homogenized to obtain an organic solvent solution, and the temperature was adjusted to 25°C. 2.2 parts of 10.0% by weight ammonia water were added as a neutralizing agent and stirred for 5 minutes. Then, 300 parts of 25°C ion-exchanged water were added dropwise over 1 hour to cause phase inversion emulsification, and methyl ethyl ketone was distilled off at 40°C under a reduced pressure of 30 kPa to obtain a dispersion (Cab-4) of resin fine particles (Ca-4). The volume-based median diameter of the resin fine particles (Ca-4) was 0.16 μm, and the solids concentration of the dispersion (Cab-4) was 20% by weight.

<Production Example 15> [Production of Dispersion (Cab-5) of Resin Fine Particles (Ca-5)]
40 parts of crystalline vinyl resin (A-5) was charged into the autoclave and replaced with nitrogen. After heating to 140°C in an open state under stirring, the mixture was sealed under stirring. A mixed solution of 42.9 parts of styrene, 16.2 parts of butyl acrylate, 0.9 parts of acrylic acid, 0.09 parts of di-t-butyl peroxide, and 6.0 parts of xylene, which are components of amorphous vinyl resin as monomer composition (B0), was dropped over 3 hours while controlling the temperature inside the autoclave to 140°C to polymerize. After dropping, the dropping line was washed with 0.4 parts of xylene. After further holding at 140°C for 1 hour, the temperature was raised to 170°C over 1 hour to decompose the initiator. After cooling to 120°C, the reaction rate of styrene was confirmed to be 95% or more, so the temperature was raised again to 170°C and the solvent was removed under a reduced pressure of 0.5 to 2.5 kPa for 5 hours. The resultant was cooled to obtain a resin composition (C-5) in which the amorphous vinyl resin was dispersed in the crystalline vinyl resin (A-5).

In addition, 100 parts of resin composition (C-5) and 100 parts of methyl ethyl ketone were charged into another reaction vessel equipped with a stirrer, a heating/cooling device, a cooling tube, and a thermometer, and the mixture was stirred and homogenized to obtain an organic solvent solution, and the temperature was adjusted to 25°C. 2.2 parts of 10.0% by weight ammonia water were added as a neutralizing agent and stirred for 5 minutes. Then, 300 parts of 25°C ion-exchanged water were added dropwise over 1 hour to cause phase inversion emulsification, and methyl ethyl ketone was distilled off at 40°C under a reduced pressure of 30 kPa to obtain a dispersion (Cab-5) of resin fine particles (Ca-5). The volume-based median diameter of the resin fine particles (Ca-5) was 0.24 μm, and the solids concentration of the dispersion (Cab-5) was 20% by weight.

<Production Example 16> [Production of Dispersion (Cab-6) of Resin Fine Particles (Ca-6)]
The autoclave was charged with 40 parts of crystalline vinyl resin (A-6) and substituted with nitrogen. After heating to 140°C in an open state under stirring, the autoclave was sealed under stirring. A mixed solution of 42.9 parts of styrene, 16.2 parts of butyl acrylate, 0.9 parts of acrylic acid, 0.09 parts of di-t-butyl peroxide, and 6.0 parts of xylene, which are components of amorphous vinyl resin as monomer composition (B0), was dropped over 3 hours while controlling the temperature inside the autoclave to 140°C to polymerize. After dropping, the dropping line was washed with 0.4 parts of xylene. After further holding at 140°C for 1 hour, the temperature was raised to 170°C over 1 hour to decompose the initiator. After cooling to 120°C, the reaction rate of styrene was confirmed to be 95% or more, so the temperature was raised again to 170°C and the solvent was removed for 5 hours under a reduced pressure of 0.5 to 2.5 kPa. The resultant was cooled to obtain a resin composition (C-6) in which the amorphous vinyl resin was dispersed in the crystalline vinyl resin (A-6).

In addition, 100 parts of resin composition (C-6) and 100 parts of methyl ethyl ketone were charged into another reaction vessel equipped with a stirrer, a heating/cooling device, a cooling tube, and a thermometer, and the mixture was stirred and homogenized to obtain an organic solvent solution, and the temperature was adjusted to 25°C. 2.2 parts of 10.0% by weight ammonia water were added as a neutralizing agent and stirred for 5 minutes. Then, 300 parts of 25°C ion-exchanged water were added dropwise over 1 hour to cause phase inversion emulsification, and methyl ethyl ketone was distilled off at 40°C under a reduced pressure of 30 kPa to obtain a dispersion (Cab-6) of resin fine particles (Ca-6). The volume-based median diameter of the resin fine particles (Ca-6) was 0.18 μm, and the solids concentration of the dispersion (Cab-6) was 20% by weight.

<Production Example 17> [Production of Dispersion (Cab-7) of Resin Fine Particles (Ca-7)]
35 parts of crystalline vinyl resin (A-1) was charged into the autoclave and replaced with nitrogen. After heating to 140°C in an open state under stirring, the mixture was sealed under stirring. A mixed solution of 46.5 parts of styrene, 17.6 parts of butyl acrylate, 1.0 parts of acrylic acid, 0.10 parts of di-t-butyl peroxide, and 6.5 parts of xylene, which are components of amorphous vinyl resin as monomer composition (B0), was dropped over 3 hours while controlling the temperature inside the autoclave to 140°C to polymerize. After dropping, the dropping line was washed with 0.4 parts of xylene. After further holding at 140°C for 1 hour, the temperature was raised to 170°C over 1 hour to decompose the initiator. After cooling to 120°C, the reaction rate of styrene was confirmed to be 95% or more, so the temperature was raised again to 170°C and the solvent was removed for 5 hours under a reduced pressure of 0.5 to 2.5 kPa. The resultant was cooled to obtain a resin composition (C-7) in which the amorphous vinyl resin was dispersed in the crystalline vinyl resin (A-1).

In addition, 100 parts of resin composition (C-7) and 100 parts of methyl ethyl ketone were charged into another reaction vessel equipped with a stirrer, a heating/cooling device, a cooling tube, and a thermometer, and the mixture was stirred and homogenized to obtain an organic solvent solution, and the temperature was adjusted to 25°C. 2.2 parts of 10.0% by weight ammonia water were added as a neutralizing agent and stirred for 5 minutes. Then, 300 parts of 25°C ion-exchanged water were added dropwise over 1 hour to cause phase inversion emulsification, and methyl ethyl ketone was distilled off at 40°C under a reduced pressure of 30 kPa to obtain a dispersion (Cab-7) of resin fine particles (Ca-7). The volume-based median diameter of the resin fine particles (Ca-7) was 0.23 μm, and the solids concentration of the dispersion (Cab-7) was 20% by weight.

<Production Example 18> [Production of Dispersion (Cab-8) of Resin Fine Particles (Ca-8)]
The autoclave was charged with 60 parts of crystalline vinyl resin (A-1) and substituted with nitrogen. After heating to 140°C in an open state under stirring, the autoclave was sealed under stirring. A mixed solution of 28.6 parts of styrene, 10.8 parts of butyl acrylate, 0.6 parts of acrylic acid, 0.06 parts of di-t-butyl peroxide, and 4.0 parts of xylene, which are components of amorphous vinyl resin as monomer composition (B0), was dropped over 3 hours while controlling the temperature inside the autoclave to 140°C to polymerize. After dropping, the dropping line was washed with 0.2 parts of xylene. After further holding at 140°C for 1 hour, the temperature was raised to 170°C over 1 hour to decompose the initiator. After cooling to 120°C, the reaction rate of styrene was confirmed to be 95% or more, so the temperature was raised again to 170°C and the solvent was removed for 5 hours under a reduced pressure of 0.5 to 2.5 kPa. The resultant was cooled to obtain a resin composition (C-8) in which the amorphous vinyl resin was dispersed in the crystalline vinyl resin (A-1).

In addition, 100 parts of resin composition (C-8) and 100 parts of methyl ethyl ketone were charged into another reaction vessel equipped with a stirrer, a heating/cooling device, a cooling tube, and a thermometer, and the mixture was stirred and homogenized to obtain an organic solvent solution, and the temperature was adjusted to 25°C. 2.2 parts of 10.0% by weight ammonia water were added as a neutralizing agent and stirred for 5 minutes. Then, 300 parts of 25°C ion-exchanged water were added dropwise over 1 hour to cause phase inversion emulsification, and methyl ethyl ketone was distilled off at 40°C under a reduced pressure of 30 kPa to obtain a dispersion (Cab-8) of resin fine particles (Ca-8). The volume-based median diameter of the resin fine particles (Ca-8) was 0.23 μm, and the solids concentration of the dispersion (Cab-8) was 20% by weight.

<Production Example 19> [Production of Dispersion (Cab-9) of Resin Fine Particles (Ca-9)]
80 parts of crystalline vinyl resin (A-1) was charged into an autoclave and replaced with nitrogen. After heating to 140°C in an open state under stirring, the mixture was sealed under stirring. A mixed solution of 14.3 parts of styrene, 5.4 parts of butyl acrylate, 0.3 parts of acrylic acid, 0.02 parts of di-t-butyl peroxide, and 2.0 parts of xylene, which are components of amorphous vinyl resin as monomer composition (B0), was dropped over 3 hours while controlling the temperature inside the autoclave to 140°C to polymerize. After dropping, the dropping line was washed with 0.1 parts of xylene. After further holding at 140°C for 1 hour, the temperature was raised to 170°C over 1 hour to decompose the initiator. After cooling to 120°C, the reaction rate of styrene was confirmed to be 95% or more, so the temperature was raised again to 170°C and the solvent was removed for 5 hours under a reduced pressure of 0.5 to 2.5 kPa. The resultant was cooled to obtain a resin composition (C-9) in which the amorphous vinyl resin was dispersed in the crystalline vinyl resin (A-1).

In addition, 100 parts of resin composition (C-9) and 100 parts of methyl ethyl ketone were charged into another reaction vessel equipped with a stirrer, a heating/cooling device, a cooling tube, and a thermometer, and the mixture was stirred and homogenized to obtain an organic solvent solution, and the temperature was adjusted to 25°C. 2.2 parts of 10.0 wt% ammonia water were added as a neutralizing agent and stirred for 5 minutes. Then, 300 parts of 25°C ion-exchanged water were added dropwise over 1 hour to cause phase inversion emulsification, and methyl ethyl ketone was distilled off at 40°C under a reduced pressure of 30 kPa to obtain a dispersion (Cab-9) of resin fine particles (Ca-9). The volume-based median diameter of the resin fine particles (Ca-9) was 0.23 μm, and the solids concentration of the dispersion (Cab-9) was 20 wt%.

<Production Example 20> [Production of Dispersion (Eab-1) of Resin Fine Particles (Ea-1)]
Next, 875 parts of the dispersion liquid (Dab-1) of resin fine particles (Da-1) was charged into a reaction vessel equipped with a stirrer, a heating and cooling device, a cooling tube, a thermometer and a nitrogen inlet tube, and the temperature in the system was raised to 70 ° C. by heating, and then a mixture of 52.0 parts of styrene, 26.8 parts of butyl acrylate, 1.2 parts of methacrylic acid, and 1.2 parts of 1-dodecyl mercaptan, which are components of the amorphous vinyl resin as the monomer composition (B0), 3.1 parts of 10 wt% tertiary butyl hydroperoxide, and 20.9 parts of 1 wt% aqueous ascorbic acid was added dropwise over 80 minutes. After the dropwise addition, 20.9 parts of a 1 wt% aqueous ascorbic acid solution was further added dropwise over 10 minutes, and then heated and stirred at 70 ° C. for 1 hour to obtain a dispersion liquid (Eab-1) of resin fine particles (Ea-1) in which the amorphous vinyl resin was dispersed in the crystalline vinyl resin (A-7). The resulting resin fine particles (Ea-1) had a volume-based median diameter of 0.25 μm and a solid content of 20% by weight. A part of the dispersion liquid (Eab-1) was dried to obtain a resin composition (C-10).

<Production Example 21> [Production of Dispersion (Cab-10) of Resin Fine Particles (Ca-10)]
The autoclave was charged with 40 parts of crystalline vinyl resin (A-8) and substituted with nitrogen. After heating to 140°C in an open state under stirring, the mixture was sealed under stirring. A mixed solution of 42.9 parts of styrene, 16.2 parts of butyl acrylate, 0.9 parts of acrylic acid, 0.09 parts of di-t-butyl peroxide, and 6.0 parts of xylene, which are components of amorphous vinyl resin as monomer composition (B0), was dropped over 3 hours while controlling the temperature inside the autoclave to 140°C to polymerize. After dropping, the dropping line was washed with 0.4 parts of xylene. After further holding at 140°C for 1 hour, the temperature was raised to 170°C over 1 hour to decompose the initiator. After cooling to 120°C, the reaction rate of styrene was confirmed to be 95% or more, so the temperature was raised again to 170°C and the solvent was removed for 5 hours under a reduced pressure of 0.5 to 2.5 kPa. The resultant was cooled to obtain a resin composition (C-11) in which an amorphous vinyl resin was dispersed in a crystalline vinyl resin (A-8).

In addition, 100 parts of resin composition (C-11) and 100 parts of methyl ethyl ketone were charged into another reaction vessel equipped with a stirrer, a heating/cooling device, a cooling tube, and a thermometer, and the mixture was stirred and homogenized to obtain an organic solvent solution, and the temperature was adjusted to 25°C. 2.2 parts of 10.0% by weight ammonia water were added as a neutralizing agent and stirred for 5 minutes. Then, 300 parts of 25°C ion-exchanged water were added dropwise over 1 hour to cause phase inversion emulsification, and methyl ethyl ketone was distilled off at 40°C under a reduced pressure of 30 kPa to obtain a dispersion (Cab-10) of resin fine particles (Ca-10). The volume-based median diameter of the resin fine particles (Ca-10) was 0.20 μm, and the solids concentration of the dispersion (Cab-10) was 20% by weight.

<Production Example 22> [Production of Dispersion (Cab-11) of Resin Fine Particles (Ca-11)]
The autoclave was charged with 40 parts of crystalline vinyl resin (A-9) and substituted with nitrogen. After heating to 140°C in an open state under stirring, the autoclave was sealed under stirring. A mixed solution of 42.9 parts of styrene, 16.2 parts of butyl acrylate, 0.9 parts of acrylic acid, 0.09 parts of di-t-butyl peroxide, and 6.0 parts of xylene, which are components of amorphous vinyl resin as monomer composition (B0), was dropped over 3 hours while controlling the temperature inside the autoclave to 140°C to polymerize. After dropping, the dropping line was washed with 0.4 parts of xylene. After further holding at 140°C for 1 hour, the temperature was raised to 170°C over 1 hour to decompose the initiator. After cooling to 120°C, the reaction rate of styrene was confirmed to be 95% or more, so the temperature was raised again to 170°C and the solvent was removed for 5 hours under a reduced pressure of 0.5 to 2.5 kPa. The resultant was cooled to obtain a resin composition (C-12) in which the amorphous vinyl resin was dispersed in the crystalline vinyl resin (A-9).

In addition, 100 parts of resin composition (C-12) and 100 parts of methyl ethyl ketone were charged into another reaction vessel equipped with a stirrer, a heating/cooling device, a cooling tube, and a thermometer, and the mixture was stirred and homogenized to obtain an organic solvent solution, and the temperature was adjusted to 25°C. 2.2 parts of 10.0% by weight ammonia water were added as a neutralizing agent and stirred for 5 minutes. Then, 300 parts of 25°C ion-exchanged water were added dropwise over 1 hour to cause phase inversion emulsification, and methyl ethyl ketone was distilled off at 40°C under a reduced pressure of 30 kPa to obtain a dispersion (Cab-11) of resin fine particles (Ca-11). The volume-based median diameter of the resin fine particles (Ca-11) was 0.15 μm, and the solids concentration of the dispersion (Cab-11) was 20% by weight.

<Production Example 23> [Production of Dispersion (Cab-12) of Resin Fine Particles (Ca-12)]
The autoclave was charged with 40 parts of crystalline vinyl resin (A-1) and substituted with nitrogen. After heating to 140°C in an open state under stirring, the mixture was sealed under stirring. A mixed solution of 24.9 parts of styrene, 16.2 parts of butyl acrylate, 0.9 parts of acrylic acid, 18.0 parts of methyl methacrylate, 0.09 parts of di-t-butyl peroxide, and 6.0 parts of xylene, which are components of the amorphous vinyl resin as the monomer composition (B0), was dropped over 3 hours while controlling the temperature inside the autoclave to 140°C to polymerize. After dropping, the dropping line was washed with 0.4 parts of xylene. After further holding at 140°C for 1 hour, the temperature was raised to 170°C over 1 hour to decompose the initiator. After cooling to 120°C, the reaction rate of styrene was confirmed to be 95% or more, so the temperature was raised again to 170°C and the solvent was removed for 5 hours under a reduced pressure of 0.5 to 2.5 kPa. The resultant was cooled to obtain a resin composition (C-13) in which the amorphous vinyl resin was dispersed in the crystalline vinyl resin (A-1).

In addition, 100 parts of resin composition (C-13) and 100 parts of methyl ethyl ketone were charged into another reaction vessel equipped with a stirrer, a heating/cooling device, a cooling tube, and a thermometer, and the mixture was stirred and homogenized to obtain an organic solvent solution, and the temperature was adjusted to 25°C. 2.2 parts of 10.0% by weight ammonia water were added as a neutralizing agent and stirred for 5 minutes. Then, 300 parts of 25°C ion-exchanged water were added dropwise over 1 hour to cause phase inversion emulsification, and methyl ethyl ketone was distilled off at 40°C under a reduced pressure of 30 kPa to obtain a dispersion (Cab-12) of resin fine particles (Ca-12). The volume-based median diameter of the resin fine particles (Ca-12) was 0.16 μm, and the solids concentration of the dispersion (Cab-12) was 20% by weight.

<Production Example 24> [Production of Dispersion (Cab-13) of Resin Fine Particles (Ca-13)]
The autoclave was charged with 40 parts of crystalline vinyl resin (A-1) and substituted with nitrogen. After heating to 140°C in an open state under stirring, the mixture was sealed under stirring. A mixed solution of 40.8 parts of styrene, 15.6 parts of butyl acrylate, 0.6 parts of acrylic acid, 3.0 parts of acrylonitrile, 0.09 parts of di-t-butyl peroxide, and 6.0 parts of xylene, which are components of the amorphous vinyl resin as the monomer composition (B0), was dropped over 3 hours while controlling the temperature inside the autoclave to 140°C to polymerize. After dropping, the dropping line was washed with 0.4 parts of xylene. After further holding at 140°C for 1 hour, the temperature was raised to 170°C over 1 hour to decompose the initiator. After cooling to 120°C, the reaction rate of styrene was confirmed to be 95% or more, so the temperature was raised again to 170°C and the solvent was removed for 5 hours under a reduced pressure of 0.5 to 2.5 kPa. The resultant was cooled to obtain a resin composition (C-14) in which the amorphous vinyl resin was dispersed in the crystalline vinyl resin (A-1).

In addition, 100 parts of resin composition (C-14) and 100 parts of methyl ethyl ketone were charged into another reaction vessel equipped with a stirrer, a heating/cooling device, a cooling tube, and a thermometer, and the mixture was stirred and homogenized to obtain an organic solvent solution, and the temperature was adjusted to 25°C. 2.2 parts of 10.0% by weight ammonia water were added as a neutralizing agent and stirred for 5 minutes. Then, 300 parts of 25°C ion-exchanged water were added dropwise over 1 hour to cause phase inversion emulsification, and methyl ethyl ketone was distilled off at 40°C under a reduced pressure of 30 kPa to obtain a dispersion (Cab-13) of resin fine particles (Ca-13). The volume-based median diameter of the resin fine particles (Ca-13) was 0.19 μm, and the solids concentration of the dispersion (Cab-13) was 20% by weight.

Comparative Production Example 1 Production of Dispersion (Cab'-1) of Resin Fine Particles (Ca'-1)
30 parts of crystalline vinyl resin (A-1) was charged into an autoclave and replaced with nitrogen. After heating to 140°C in an open state under stirring, the mixture was sealed under stirring. A mixed solution of 58.4 parts of styrene, 22.1 parts of butyl acrylate, 1.2 parts of acrylic acid, 0.12 parts of di-t-butyl peroxide, and 8.2 parts of xylene, which are components of amorphous vinyl resin as monomer composition (B0), was dropped over 3 hours while controlling the temperature inside the autoclave to 140°C to polymerize. After dropping, the dropping line was washed with 0.5 parts of xylene. After further holding at 140°C for 1 hour, the temperature was raised to 170°C over 1 hour to decompose the initiator. After cooling to 120°C, the reaction rate of styrene was confirmed to be 95% or more, so the temperature was raised again to 170°C and the solvent was removed for 5 hours under a reduced pressure of 0.5 to 2.5 kPa. The resultant was cooled to obtain a resin composition (C'-1) in which the crystalline vinyl resin (A-1) was dispersed in the amorphous vinyl resin.

In addition, 100 parts of resin composition (C'-1) and 100 parts of methyl ethyl ketone were charged into another reaction vessel equipped with a stirrer, a heating/cooling device, a cooling tube, and a thermometer, and the mixture was stirred and homogenized to obtain an organic solvent solution, and the temperature was adjusted to 25°C. 2.2 parts of 10.0 wt% ammonia water were added as a neutralizing agent and stirred for 5 minutes. Then, 300 parts of 25°C ion-exchanged water were added dropwise over 1 hour to cause phase inversion emulsification, and methyl ethyl ketone was distilled off at 40°C under a reduced pressure of 30 kPa to obtain a dispersion (Cab'-1) of resin fine particles (Ca'-1). The volume-based median diameter of the resin fine particles (Ca'-1) was 0.20 μm, and the solids concentration of the dispersion (Cab'-1) was 20 wt%.

Comparative Production Example 2 Production of Dispersion (Cab'-2) of Resin Fine Particles (Ca'-2)
The crystalline vinyl resin (A-4) of Production Example 5 was used as the resin composition (C'-2), and 100 parts of the resin composition (C'-2) and 100 parts of methyl ethyl ketone were charged into another reaction vessel equipped with a stirring device, a heating and cooling device, a cooling tube and a thermometer, and the organic solvent solution was obtained by stirring and homogenizing, and the temperature was adjusted to 25 ° C. 2.2 parts of 10.0 wt% ammonia water was added thereto as a neutralizing agent and stirred for 5 minutes. Thereafter, 300 parts of 25 ° C. ion exchange water was dropped over 1 hour to cause phase inversion emulsification, and methyl ethyl ketone was distilled off at 40 ° C. under a reduced pressure of 30 kPa to obtain a dispersion (Cab'-2) of resin fine particles (Ca'-2). The volume-based median diameter of the resin fine particles (Ca'-2) was 0.22 μm, and the solid concentration of the dispersion (Cab'-2) was 20 wt%.

Comparative Production Example 3 Production of Dispersion (Cab'-3) of Resin Fine Particles (Ca'-3)
23 parts of xylene was charged into the autoclave and replaced with nitrogen. After heating to 140°C under open stirring, the autoclave was sealed. A mixed solution of 71.5 parts of styrene, 27.0 parts of butyl acrylate [manufactured by Mitsubishi Chemical Corporation, the same applies below], 1.5 parts of acrylic acid, 0.15 parts of di-t-butyl peroxide, and 9 parts of xylene was dropped over 3 hours while controlling the temperature inside the autoclave to 140°C to polymerize. After dropping, the dropping line was washed with 1 part of xylene. After further holding at 140°C for 1 hour, the temperature was raised to 170°C over 1 hour to decompose the initiator. After cooling to 120°C, the reaction rate of styrene was confirmed to be 95% or more, so the temperature was raised again to 170°C and the solvent was removed under a reduced pressure of 0.5 to 2.5 kPa for 5 hours under a reduced pressure of 0.5 to 2.5 kPa to obtain a resin composition (C'-3) which is an amorphous vinyl resin. The glass transition temperature of (C'-3) was 55°C and the acid value was 12 mgKOH/g.

In addition, 100 parts of resin composition (C'-3) and 100 parts of methyl ethyl ketone were charged into another reaction vessel equipped with a stirrer, a heating/cooling device, a cooling tube, and a thermometer, and the mixture was stirred and homogenized to obtain an organic solvent solution, and the temperature was adjusted to 25°C. 2.2 parts of 10.0 wt% ammonia water were added as a neutralizing agent and stirred for 5 minutes. Then, 300 parts of 25°C ion-exchanged water were added dropwise over 1 hour to cause phase inversion emulsification, and methyl ethyl ketone was distilled off at 40°C under a reduced pressure of 30 kPa to obtain a dispersion (Cab'-3) of resin fine particles (Ca'-3). The volume-based median diameter of the resin fine particles (Ca'-3) was 0.18 μm, and the solids concentration of the dispersion (Cab'-3) was 20 wt%.

Comparative Production Example 4 Production of Dispersion (Cab'-4) of Resin Fine Particles (Ca'-4)
60 parts of the crystalline vinyl resin (A-1) and 40 parts of the resin composition (C'-3) which is an amorphous vinyl resin were mixed, fed to a twin-screw kneader, and kneaded for 2 minutes at 140° C. The resultant was cooled to obtain a resin composition (C'-4) in which the amorphous vinyl resin was dispersed in the crystalline vinyl resin (A-1).

In addition, 100 parts of resin composition (C'-4) and 100 parts of methyl ethyl ketone were charged into another reaction vessel equipped with a stirrer, a heating/cooling device, a cooling tube, and a thermometer, and the mixture was stirred and homogenized to obtain an organic solvent solution, and the temperature was adjusted to 25°C. 2.2 parts of 10.0 wt% ammonia water were added as a neutralizing agent and stirred for 5 minutes. Then, 300 parts of 25°C ion-exchanged water were added dropwise over 1 hour to cause phase inversion emulsification, and methyl ethyl ketone was distilled off at 40°C under a reduced pressure of 30 kPa to obtain a dispersion (Cab'-4) of resin fine particles (Ca'-4). The volume-based median diameter of the resin fine particles (Ca'-4) was 0.25 μm, and the solids concentration of the dispersion (Cab'-4) was 20 wt%.

Comparative Production Example 5 Production of Dispersion (Cab'-5) of Resin Fine Particles (Ca'-5)
The autoclave was charged with 40 parts of crystalline vinyl resin (A-1) and substituted with nitrogen. After heating to 140°C in an open state under stirring, the autoclave was sealed under stirring. A mixed solution of 16.2 parts of butyl acrylate, 0.9 parts of acrylic acid, 42.9 parts of methyl methacrylate, 0.09 parts of di-t-butyl peroxide, and 6.0 parts of xylene, which are components of amorphous vinyl resin as monomer composition (B0), was dropped over 3 hours while controlling the temperature inside the autoclave to 140°C to polymerize. After dropping, the dropping line was washed with 0.4 parts of xylene. After further holding at 140°C for 1 hour, the temperature was raised to 170°C over 1 hour to decompose the initiator. After cooling to 120°C, the reaction rate of methyl methacrylate was confirmed to be 95% or more, so the temperature was raised again to 170°C and the solvent was removed under a reduced pressure of 0.5 to 2.5 kPa for 5 hours. The resultant was cooled to obtain a resin composition (C'-5) in which the amorphous vinyl resin was dispersed in the crystalline vinyl resin (A-1).

In addition, 100 parts of resin composition (C'-5) and 100 parts of methyl ethyl ketone were charged into another reaction vessel equipped with a stirrer, a heating/cooling device, a cooling tube, and a thermometer, and the mixture was stirred and homogenized to obtain an organic solvent solution, and the temperature was adjusted to 25°C. 2.2 parts of 10.0 wt% ammonia water were added as a neutralizing agent and stirred for 5 minutes. Then, 300 parts of 25°C ion-exchanged water were added dropwise over 1 hour to cause phase inversion emulsification, and methyl ethyl ketone was distilled off at 40°C under a reduced pressure of 30 kPa to obtain a dispersion (Cab'-5) of resin fine particles (Ca'-5). The volume-based median diameter of the resin fine particles (Ca'-5) was 0.16 μm, and the solids concentration of the dispersion (Cab'-5) was 20 wt%.

The compositions and physical properties of resin compositions (C-1) to (C-14) and (C'-1) to (C'-5) are shown in Table 2.

[Preparation of colorant dispersion]
In a reaction vessel equipped with a stirrer, a heating/cooling device, a cooling tube, and a thermometer, 10 parts of carbon black [MA100 manufactured by Mitsubishi Chemical Corporation], 0.5 parts of sodium dodecylbenzenesulfonate, and 40 parts of ion-exchanged water were added, and the temperature was raised to 30° C. while stirring at a rotation speed of 300 rpm, and after stirring at the same temperature for 30 minutes, the mixture was further wet-pulverized with an Ultraviscomill to obtain a black colorant dispersion. The volume-based median diameter of the obtained black colorant dispersion was 0.05 μm, and the solid content concentration was 20% by weight.

[Preparation of release agent dispersion]
In a reaction vessel equipped with a stirrer, a heating/cooling device, a cooling tube, and a thermometer, 10 parts of Fischer-Tropsch wax [FT-0070 manufactured by Nippon Seiro Co., Ltd.], 0.5 parts of sodium dodecylbenzenesulfonate, and 15 parts of ion-exchanged water were added, and the temperature was raised to 95°C while stirring at a rotation speed of 300 rpm, and after stirring at the same temperature for 30 minutes, the temperature was cooled to 30°C over 1 hour to crystallize the Fischer-Tropsch wax into fine particles, which were then wet-pulverized with an Ultraviscomill to obtain a release agent dispersion. The volume-based median diameter of the obtained release agent dispersion was 0.25 μm, and the solid content concentration was 50% by weight.

Example 1
[Preparation of Toner (T-1)]
A reaction vessel equipped with a stirrer, a heating/cooling device, a cooling tube, a thermometer and a nitrogen inlet tube was charged with the dispersion liquid (Cab-1) of resin fine particles (Ca-1), the colorant dispersion liquid and the release agent dispersion liquid so as to have the solid contents in parts as shown in Table 3, 300 parts of ion-exchanged water was charged, the liquid temperature was adjusted to 30° C., and then a 25% by weight aqueous sodium hydroxide solution was added with stirring to adjust the pH to 10, thereby obtaining a dispersion liquid.
Next, in order to aggregate the resin fine particles (Ca-1), colorant, and release agent, a magnesium chloride aqueous solution having a concentration of 10% by weight was added as an aggregating agent while stirring at a rotation speed of 300 rpm, and after appropriate sampling was performed to confirm that the volume average particle size had reached 5 μm, the temperature of the system was adjusted to 60° C., and then a 0.3 M nitric acid aqueous solution was added to adjust the pH to 4.5, and after 30 minutes, the pH was adjusted to 4.0. The mixture was kept stirred for 3 hours to perform fusion and spheroidization.
The mixture was then cooled to 30° C. to obtain an aqueous dispersion of the aggregate containing the colorant. The aggregate was then filtered and washed with water three times, filtered, and dried for 18 hours in a 40° C. air circulation dryer to obtain aggregate (Z-1) having a volatile content of 0.5% by weight or less. 99 parts by weight of the obtained aggregate (Z-1) and 1 part by weight of hydrophobic silica [Aerosil R972, manufactured by Nippon Aerosil Co., Ltd.] were uniformly mixed to obtain toner (T-1) of the present invention in which amorphous vinyl resin is dispersed as particles in the toner.

The dispersion state and number average particle size of the amorphous vinyl resin in the toner (T-1) were measured by the following measuring method using the obtained toner.
The obtained toner was ultra-thinly sliced to about 100 μm, and the amorphous vinyl resin in the toner was stained with ruthenium tetroxide at a concentration of 1 for 3 minutes using a vacuum electron staining device (VSC1R1H manufactured by Filgen Co., Ltd.). The cross section of the toner was then observed at a magnification of 10,000 times using a transmission electron microscope (TEM) to observe whether the amorphous vinyl resin, which appeared gray or black when stained with ruthenium tetroxide, was dispersed as particles in the toner.
The particle size of the amorphous vinyl resin in the toner was calculated by image analysis using an image processing device (Keyence Digital Microscope VHX-700F). Measurement was performed at the distance between two points, and the diameter was measured when the amorphous vinyl resin was a perfect circle, and the major axis was measured when the amorphous vinyl resin was an ellipse. The results of randomly measuring 30 points were calculated as the number average to calculate the number average dispersed particle size of the amorphous vinyl resin in the toner.

<Examples 2 to 14> [Production of Toners (T-2) to (T-14)]
Except for changing the raw materials used to those shown in Tables 3 and 4, the same procedure as in Example 1 was repeated to obtain toners (T-2) to (T-14) in which the amorphous vinyl resin was dispersed as particles in the toner.

Comparative Examples 1 to 5 [Production of Toners (T'-1) to (T'-5)]
Toners (T'-1) to (T'-5) were obtained in the same manner as in Example 1, except that the raw materials were changed to those shown in Tables 3 and 4. Note that in toner (T'-1), the sea-island structure was inverted and the crystalline vinyl resin (A) was dispersed in the toner, toner (T'-2) did not contain an amorphous vinyl resin, and toner (T'-3) used only an amorphous vinyl resin as the resin, so that the amorphous vinyl resin was not dispersed as particles in the toner.

The compositions, analytical values, and evaluation results of the aggregates and toners obtained in each Example and Comparative Example are shown in Tables 3 and 4.

[Evaluation method]
The evaluation method and criteria for the obtained toner are described below.

<Low temperature fixability>
The toner was uniformly placed on the paper surface to a concentration of 1.00 mg/ ^cm2 . The powder was placed on the paper surface using a printer without a thermal fixing device. The paper was passed through a soft roller at a fixing speed (heating roller peripheral speed) of 213 mm/sec and at a heating roller temperature range of 90 to 230°C in 5°C increments. The fixed image was then visually inspected for the presence or absence of cold offset, and the cold offset occurrence temperature (MFT) was measured.
The lower the temperature at which cold offset occurs, the better the low-temperature fixing ability. Under these evaluation conditions, it is generally preferable that the MFT is 125° C. or less.

<Hot offset resistance>
In the same manner as described above for low-temperature fixability, the toner was placed on the paper surface, and the paper was passed through a soft roller at a fixing speed (circumferential speed of the heating roller) of 213 mm/sec, and at heating roller temperatures ranging from 90 to 230° C. in increments of 5° C. Next, the presence or absence of hot offset on the fixed image was visually observed, and the temperature at which hot offset occurred was measured.
A higher hot offset occurrence temperature means better hot offset resistance. In this evaluation condition, a temperature of 180° C. or higher is preferable.

<Charge stability>
(1) 0.5 g of toner and 20 g of ferrite carrier (F-150, manufactured by Powder Tech Co., Ltd.) were placed in a 50 mL glass bottle, and the bottle was conditioned at 23° C. and a relative humidity of 50% for 8 hours or more.
(2) The mixture was subjected to friction stirring at 50 rpm for 10 minutes and 60 minutes using a Turbulent shaker mixer, and the charge amount after each time was measured using a blow-off charge amount measuring device (manufactured by Kyocera Chemical Corporation).
Using the obtained values, "charge amount after 60 minutes of friction/charge amount after 10 minutes of friction" was calculated, and this was taken as the charge stability index.
A larger charge stability index indicates better charge stability. Under these evaluation conditions, a charge stability index of 0.8 or more is preferable.

As is clear from the evaluation results in Table 4, the toners (T-1) to (T-14) according to Examples 1 to 14 all achieved excellent results in all performance evaluations. On the other hand, the toners (T'-1) to (T'-5) according to Comparative Examples 1 to 5 were poor in some performance items.

The toner obtained by the production method of the present invention can be suitably used as a toner for developing electrostatic images in electrophotography, electrostatic recording, electrostatic printing and the like.
Furthermore, it is useful as a resin for applications such as paint additives, adhesive additives, and particles for electronic paper.

Claims (3)

A method for producing a toner, comprising aggregating resin fine particles including a resin composition (C) obtained by polymerizing a monomer composition (B0) in the presence of a crystalline vinyl resin (A), the method comprising the steps of:
The crystalline vinyl resin (A) is a polymer of a monomer composition (A0) containing a monomer (a),
A method for producing a toner, wherein the monomer (a) is a (meth)acrylate having 21 to 40 carbon atoms and a chain hydrocarbon group, the monomer composition (A0) contains a monomer (b1) having a nitrile group, the monomer composition (B0) contains 30% by weight or more of a styrene monomer based on the total weight of the monomer composition (B0), and the weight ratio [(A)/(B0)] of the crystalline vinyl resin (A) to the monomer composition (B0) before reaction is 35/65 to 80/20. 2. The method for producing a toner according to claim 1 , wherein a weight ratio of said monomer (a) in said monomer composition (A0) is 15 to 93% by weight based on the weight of said monomer composition (A0). 3. The method for producing a toner according to claim 1 , wherein the toner has an acid value of 5 to 20 mgKOH/g.