JP2024092598A - Toner for developing electrostatic images - Google Patents

Abstract

To provide a toner for electrostatic charge image development which is excellent in durability and scratch resistance, and a method for manufacturing the same.SOLUTION: There are provided a toner for electrostatic charge image development containing a binder resin and a release agent, wherein the binder resin contains a composite X containing a raw material monomer of a polyester resin, and a polycondensate of a hydrogenated terpene phenol resin; and a method for manufacturing a toner for electrostatic charge image development containing a binder resin and a release agent, wherein the binder resin contains a composite X containing a raw material monomer of a polyester resin, and a polycondensate of a hydrogenated terpene phenol resin, including a step 1 of melting and kneading at least the binder resin and the release agent, and a step 2 of crushing and classifying the molten and kneaded material obtained in the step 1.SELECTED DRAWING: None

Description

The present invention relates to a toner for developing electrostatic images, which is used to develop latent images formed in, for example, electrophotography, electrostatic recording, electrostatic printing, etc., and a method for producing the same.

In recent years, terpene phenol resins have been considered as new resin materials for use in toner (see Patent Documents 1 and 2).

JP 2021-196504 A JP 2019-28261 A

Terpene phenol resin is effective in improving durability because it blends well with wax (release agent), and has low surface tension, making it highly slippery and expected to improve the scratch resistance of printed matter. However, simply mixing terpene phenol resin with polyester resin, which is widely used as a binder resin, results in poor dispersion of the terpene phenol resin in the polyester resin, making it difficult to achieve the above-mentioned effects.

The present invention relates to a toner for developing electrostatic images that has excellent durability and abrasion resistance, and a method for producing the same.

The present invention relates to
[1] A toner for developing electrostatic images, comprising a binder resin and a release agent, the binder resin comprising a composite resin X comprising a raw material monomer for a polyester resin and a polycondensate of a hydrogenated terpene phenol resin; and [2] a toner for developing electrostatic images, comprising a binder resin and a release agent, the binder resin comprising a composite resin X comprising a raw material monomer for a polyester resin and a polycondensate of a hydrogenated terpene phenol resin, the method for producing the toner for developing electrostatic images comprising the steps of:
The present invention relates to a method for producing a toner for developing an electrostatic image, comprising: step 1: a step of melting and kneading at least the binder resin and the release agent; and step 2: a step of pulverizing and classifying the melt-kneaded product obtained in step 1.

The toner for developing electrostatic images of the present invention exhibits excellent durability and abrasion resistance.

The toner for developing electrostatic images of the present invention contains a binder resin containing composite resin X, which contains a polycondensate of raw material monomers for polyester resin and hydrogenated terpene phenol resin, and a release agent. Although the details are unknown, it is presumed that the effects of the present invention are achieved through the following mechanism.

Terpene phenol resin has low reactivity with the raw monomer of polyester resin, and it is difficult to compound it into a resin. However, in the present invention, it has been found that by using hydrogenated terpene phenol resin obtained by hydrogenating terpene phenol resin, compounding with polyester resin becomes easy, and an effect that cannot be obtained by simply mixing terpene phenol resin and polyester resin is achieved. That is, by polycondensing and compounding the raw monomer of polyester resin and hydrogenated terpene phenol resin, hydrogenated terpene phenol resin is uniformly present in polyester resin. As a result, wax (release agent) that is compatible with hydrogenated terpene phenol resin can be uniformly present in polyester resin, and the durability of the toner is improved. Furthermore, hydrogenated terpene phenol resin with high slipperiness is uniformly present in the toner, and the scratch resistance of the printed matter is improved.

Composite resin X contains a polycondensate of raw material monomers for polyester resin and hydrogenated terpene phenol resin.

Composite resin X may be either an amorphous resin or a crystalline resin, but from the viewpoint of durability, it is preferable that it is an amorphous resin.

The crystallinity of a resin is represented by a crystallinity index defined as the ratio of the softening point to the maximum endothermic peak temperature measured by a differential scanning calorimeter, that is, the value of [softening point/maximum endothermic peak temperature].
The crystalline resin is a resin having a crystallinity index of 0.6 or more, preferably 0.7 or more, more preferably 0.9 or more, and 1.4 or less, preferably 1.2 or less, more preferably 1.1 or less.
On the other hand, an amorphous resin is a resin in which no endothermic peak is observed, or if an endothermic peak is observed, the crystallinity index is greater than 1.4, preferably greater than 1.5, more preferably 1.6 or more, or less than 0.6, preferably 0.5 or less.
The crystallinity of the resin can be adjusted by the type and ratio of the raw material monomers, and the production conditions (e.g., reaction temperature, reaction time, cooling rate), etc. The maximum endothermic peak temperature refers to the temperature of the peak with the largest peak area among the observed endothermic peaks. In the case of a crystalline resin, the maximum endothermic peak temperature is the melting point.

Below, we will explain an embodiment (first embodiment) in which the composite resin X is an amorphous resin (amorphous composite resin AX) and an embodiment (second embodiment) in which the composite resin X is a crystalline resin (crystalline composite resin CX).

In the first embodiment, from the viewpoint of durability, the raw material monomers for the polyester resin are preferably an alcohol component containing an alkylene oxide adduct of bisphenol A and a carboxylic acid component containing an aromatic dicarboxylic acid compound.

The alkylene oxide adduct of bisphenol A is represented by the formula (I):

(In the formula, OR and RO are oxyalkylene groups, R is an ethylene group and/or a propylene group, x and y are the average number of moles of alkylene oxide added, each of which is a positive number, and the sum of x and y is 1 or more, preferably 1.5 or more, and 16 or less, preferably 8 or less, more preferably 6 or less, and even more preferably 4 or less.)
Preferred is a compound represented by the following formula:

Examples of the alkylene oxide adduct of bisphenol A represented by formula (I) include a polyoxypropylene adduct of 2,2-bis(4-hydroxyphenyl)propane, a polyoxyethylene adduct of 2,2-bis(4-hydroxyphenyl)propane, etc. It is preferable to use one or more of these.

The content of the alkylene oxide adduct of bisphenol A represented by formula (I) in the alcohol component is preferably 70 mol% or more, more preferably 80 mol% or more, even more preferably 90 mol% or more, even more preferably 95 mol% or more, and even more preferably 100 mol%.

Other alcohol components include aliphatic diols such as ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,4-butenediol, 1,3-butanediol, and neopentyl glycol, as well as trihydric or higher alcohols such as bisphenol A, hydrogenated bisphenol A, and glycerin.

Examples of aromatic dicarboxylic acid compounds include phthalic acid, isophthalic acid, terephthalic acid, anhydrides of these acids, and alkyl esters in which the alkyl group has 1 to 3 carbon atoms. Among these, terephthalic acid or isophthalic acid is preferred from the viewpoint of low-temperature fixability, and terephthalic acid is more preferred.

From the viewpoint of heat-resistant storage stability, the content of the aromatic dicarboxylic acid compound in the carboxylic acid component is preferably 40 mol% or more, more preferably 60 mol% or more, even more preferably 80 mol% or more, even more preferably 90 mol% or more, even more preferably 95 mol% or more, and even more preferably 100 mol%.

Other carboxylic acid components include fumaric acid, maleic acid, succinic acid, succinic acid derivatives substituted with a hydrocarbon group, aliphatic dicarboxylic acids such as glutaric acid, adipic acid, and sebacic acid, trivalent or higher carboxylic acids such as trimellitic acid and pyromellitic acid, anhydrides of these acids, and alkyl esters of these acids having 1 to 3 carbon atoms.

The alcohol component may appropriately contain a monohydric alcohol, and the carboxylic acid component may appropriately contain a monovalent carboxylic acid compound.

In this specification, macromonomers and hydroxycarboxylic acids are not included in the alcohol component and carboxylic acid component.

From the viewpoint of adjusting the softening point of the polyester resin, the equivalent ratio of the carboxyl groups of the carboxylic acid component to the hydroxyl groups of the alcohol component (COOH groups/OH groups) is preferably 0.6 or more, more preferably 0.7 or more, even more preferably 0.75 or more, and is preferably 1.2 or less, more preferably 1.15 or less.

In this specification, hydrogenated terpene phenol resin refers to a resin obtained by hydrogenating a terpene resin obtained by copolymerizing a terpene monomer and phenol.

As the terpene monomer, at least one monoterpene selected from the group consisting of α-pinene, β-pinene, and limonene is preferred.

For example, hydrogenated terpene phenol resin, which is a copolymer of α-pinene and phenol, has the formula (II):

It is a resin having a repeating unit represented by the formula:

Commercially available hydrogenated terpene phenol resins include YS Polystar UH115 (manufactured by Yasuhara Chemical Co., Ltd.).

From the viewpoint of improving durability, the softening point of the hydrogenated terpene phenol resin is preferably 100°C or higher, more preferably 105°C or higher, and even more preferably 110°C or higher, and from the viewpoint of improving low-temperature fixability, it is preferably 160°C or lower, more preferably 150°C or lower, and even more preferably 140°C or lower.

From the viewpoint of transferability, the glass transition temperature of the hydrogenated terpene phenol resin is preferably 30°C or higher, more preferably 40°C or higher, and even more preferably 50°C or higher, and from the viewpoint of low-temperature fixability, it is preferably 90°C or lower, more preferably 80°C or lower, and even more preferably 70°C or lower.

The weight average molecular weight of the hydrogenated terpene phenol resin is preferably 300 or more, more preferably 500 or more, and even more preferably 600 or more, from the viewpoint of transferability, and is preferably 10,000 or less, more preferably 5,000 or less, and even more preferably 2,000 or less, from the viewpoint of low-temperature fixability.

From the viewpoint of improving transferability, the hydroxyl value of the hydrogenated terpene phenol resin is preferably 5 mg/KOH or more, more preferably 10 mg/KOH or more, even more preferably 15 mg/KOH or more, and is preferably 200 mg/KOH or less, more preferably 160 mg/KOH or less, even more preferably 120 mg/KOH or less, even more preferably 80 mgKOH/g or less, even more preferably 50 mgKOH/g or less.

The polycondensation product of raw material monomers for polyester resin and hydrogenated terpene phenol resin is obtained by subjecting these raw material monomers and hydrogenated terpene phenol resin to a polycondensation reaction when polycondensing alcohol components and carboxylic acid components as raw material monomers for polyester resin.

The alcohol component and the carboxylic acid component can be polycondensed in an inert gas atmosphere, preferably in the presence of an esterification catalyst, and if necessary, in the presence of an esterification promoter, a polymerization inhibitor, etc., at a temperature of preferably 160°C or higher, more preferably 200°C or higher, and preferably 250°C or lower, more preferably 240°C or lower.

Examples of the esterification catalyst include tin compounds such as dibutyltin oxide and tin(II) 2-ethylhexanoate, and titanium compounds such as titanium diisopropylate bistriethanolamine. The amount of the esterification catalyst used is preferably 0.01 parts by mass or more, more preferably 0.1 parts by mass or more, and preferably 1.5 parts by mass or less, and more preferably 1 part by mass or less, relative to 100 parts by mass of the total amount of the alcohol component and the carboxylic acid component. Examples of the esterification promoter include gallic acid. The amount of the esterification promoter used is preferably 0.001 parts by mass or more, more preferably 0.01 parts by mass or more, and preferably 0.5 parts by mass or less, and more preferably 0.1 parts by mass or less, relative to 100 parts by mass of the total amount of the alcohol component and the carboxylic acid component. Examples of the polymerization inhibitor include tert-butylcatechol. The amount of the polymerization inhibitor used is preferably 0.001 parts by mass or more, more preferably 0.01 parts by mass or more, and preferably 0.5 parts by mass or less, more preferably 0.1 parts by mass or less, per 100 parts by mass of the total amount of the alcohol component and the carboxylic acid component.

The mass ratio of hydrogenated terpene phenol resin to raw material monomer of polyester resin in composite resin X (hydrogenated terpene phenol resin/raw material monomer of polyester resin) is preferably 5/95 or more, more preferably 10/90 or more, even more preferably 15/85 or more, and is preferably 40/60 or less, more preferably 30/70 or less, even more preferably 25/75 or less.

The amorphous composite resin AX may further be a resin obtained using raw material monomers of a styrene-based resin.

The raw material monomers for styrene-based resins include at least styrene or styrene derivatives such as α-methylstyrene and vinyltoluene (hereinafter, styrene and styrene derivatives are collectively referred to as "styrene compounds").

The content of the styrene compound, preferably styrene, in the raw material monomer of the styrene-based resin is preferably 50% by mass or more, more preferably 70% by mass or more, even more preferably 80% by mass or more, and 100% by mass or less, from the viewpoint of storage stability, and is preferably 95% by mass or less, more preferably 90% by mass or less, from the viewpoint of low-temperature fixability.

The styrene-based resin may also contain, as a raw material monomer, an alkyl (meth)acrylate ester having an alkyl group with 7 or more carbon atoms. Examples of alkyl (meth)acrylate esters include 2-ethylhexyl (meth)acrylate, (iso)octyl (meth)acrylate, (iso)decyl (meth)acrylate, and (iso)stearyl (meth)acrylate. It is preferable to use one or more of these. In this specification, "(iso)" means that both the case where this group is present and the case where it is not present are included, and when these groups are not present, it indicates that it is normal. Furthermore, "(meth)acrylic acid" refers to acrylic acid, methacrylic acid, or both.

The number of carbon atoms in the alkyl group in the (meth)acrylic acid alkyl ester used as a raw material monomer for the styrene-based resin is preferably 7 or more, more preferably 8 or more, and preferably 12 or less, more preferably 10 or less, from the viewpoint of improving the low-temperature fixing property of the toner. The number of carbon atoms in the alkyl ester refers to the number of carbon atoms derived from the alcohol component that constitutes the ester.

The raw material monomers for styrene-based resins may include raw material monomers other than styrene compounds and (meth)acrylic acid alkyl esters, for example, ethylenically unsaturated monoolefins such as ethylene and propylene; diolefins such as butadiene; halovinyls such as vinyl chloride; vinyl esters such as vinyl acetate and vinyl propionate; ethylenically monocarboxylic acid esters such as dimethylaminoethyl (meth)acrylate; vinyl ethers such as methyl vinyl ether; vinylidene halides such as vinylidene chloride; and N-vinyl compounds such as N-vinylpyrrolidone.

The addition polymerization reaction of the raw material monomers for styrene-based resins can be carried out in the presence of a polymerization initiator such as dibutyl peroxide or dicumyl peroxide, a chain transfer agent, a crosslinking agent, etc., in the presence of an organic solvent or without a solvent, by a conventional method, and the temperature conditions are preferably 110°C or higher, more preferably 140°C or higher, and preferably 200°C or lower, more preferably 170°C or lower.

When an organic solvent is used in the addition polymerization reaction, xylene, toluene, methyl ethyl ketone, acetone, etc. can be used. The amount of the organic solvent used is preferably 10 parts by mass or more and 50 parts by mass or less per 100 parts by mass of the raw material monomer of the styrene-based resin.

In the amorphous composite resin AX, it is more preferable that the polyester resin and the styrene-based resin are chemically bonded via a bireactive monomer that can react with both the raw material monomers of the polyester resin and the raw material monomers of the styrene-based resin.

The bireactive monomer is preferably a compound having at least one functional group selected from the group consisting of hydroxyl group, carboxyl group, epoxy group, primary amino group, and secondary amino group, preferably a hydroxyl group and/or a carboxyl group, more preferably a carboxyl group, and an ethylenically unsaturated bond in the molecule, more preferably at least one selected from the group consisting of acrylic acid, methacrylic acid, fumaric acid, maleic acid, and maleic anhydride, and from the viewpoint of reactivity of polycondensation reaction and addition polymerization reaction, at least one selected from the group consisting of acrylic acid, methacrylic acid, and fumaric acid is even more preferable. However, when used together with a polymerization inhibitor, a polyvalent carboxylic acid compound having an ethylenically unsaturated bond such as fumaric acid functions as a raw material monomer for polyester resin. In this case, fumaric acid, etc. is not a bireactive monomer, but a raw material monomer for polyester resin.

The amount of the bireactive monomer used is preferably 1 mol or more, more preferably 2 mol or more, relative to 100 mol of the total of the alcohol components of the polyester resin, from the viewpoint of increasing the dispersibility of the styrene resin and the polyester resin and improving the durability of the toner, and from the viewpoint of low-temperature fixing property, is preferably 30 mol or less, more preferably 20 mol or less, and even more preferably 10 mol or less.
The amount of the bireactive monomer used is preferably 1 part by mass or more, more preferably 2 parts by mass or more, relative to 100 parts by mass of the raw material monomers of the styrene resin, from the viewpoint of increasing the dispersibility of the styrene resin and the polyester resin and improving the durability of the toner, and is preferably 30 parts by mass or less, more preferably 20 parts by mass or less, and even more preferably 10 parts by mass or less, from the viewpoint of low-temperature fixability. Here, the polymerization initiator is included in the total amount of the raw material monomers of the styrene resin.

Specifically, the amorphous composite resin AX containing a styrene-based resin is preferably produced by the following method. The hydrogenated terpene phenol resin is used together with the raw material monomer of the polyester resin, and when a bireactive monomer is used, the bireactive monomer is preferably used in an addition polymerization reaction together with the raw material monomer of the styrene-based resin.

(i) A method of carrying out step (A) of polycondensation reaction with raw material monomers of polyester resin, followed by step (B) of addition polymerization reaction with raw material monomers of styrene resin and bireactive monomers. In this method, step (A) is carried out under reaction temperature conditions suitable for polycondensation reaction, the reaction temperature is lowered, and step (B) is carried out under temperature conditions suitable for addition polymerization reaction. The raw material monomers of styrene resin and bireactive monomers are preferably added to the reaction system at a temperature suitable for addition polymerization reaction. The bireactive monomers carry out addition polymerization reaction and also react with polyester resin.
After step (B), the reaction temperature is increased again, and if necessary, a raw material monomer of a polyester resin having a valence of 3 or more and serving as a crosslinking agent is added to the polymerization system, so that the polycondensation reaction of step (A) and the reaction with the bireactive monomer can be further promoted.

(ii) A method in which step (B) of an addition polymerization reaction of raw material monomers of a styrene-based resin and a bireactive monomer is followed by step (A) of a polycondensation reaction of raw material monomers of a polyester resin. In this method, step (B) is carried out under reaction temperature conditions suitable for an addition polymerization reaction, and the reaction temperature is raised to carry out the polycondensation reaction of step (A) under temperature conditions suitable for a polycondensation reaction. The bireactive monomer is involved in both the polycondensation reaction as well as the addition polymerization reaction.
The raw material monomers of the polyester resin may be present in the reaction system during the addition polymerization reaction, or may be added to the reaction system under temperature conditions suitable for the polycondensation reaction. In the former case, the progress of the polycondensation reaction can be controlled by adding an esterification catalyst at a temperature suitable for the polycondensation reaction.

(iii) A method of carrying out the reaction under conditions in which the step (A) of the polycondensation reaction of the raw material monomer of the polyester resin and the step (B) of the addition polymerization reaction of the raw material monomer of the styrene resin and the bireactive monomer proceed in parallel. In this method, it is preferable to carry out the steps (A) and (B) in parallel under reaction temperature conditions suitable for the addition polymerization reaction, raise the reaction temperature, add a raw material monomer of the polyester resin having a valence of 3 or more as a crosslinking agent to the polymerization system as necessary under temperature conditions suitable for the polycondensation reaction, and further carry out the polycondensation reaction of step (A). At that time, under temperature conditions suitable for the polycondensation reaction, it is also possible to add a polymerization inhibitor to proceed with only the polycondensation reaction. The bireactive monomer is involved in the polycondensation reaction as well as the addition polymerization reaction.

In the above method (i), a prepolymerized polycondensation resin may be used instead of step (A) in which a polycondensation reaction is carried out. In the above method (iii), when the reaction is carried out under conditions in which steps (A) and (B) proceed in parallel, a mixture containing raw material monomers for a styrene resin may be dripped into a mixture containing raw material monomers for a polyester resin to cause the reaction.

The above methods (i) to (iii) are preferably carried out in the same container.

The mass ratio of the polyester resin to the styrene resin in the amorphous composite resin AX (polyester resin/styrene resin) is preferably 98/2 or less, more preferably 95/5 or less, and even more preferably 90/10 or less from the viewpoint of durability, and is preferably 60/40 or more, more preferably 70/30 or more, and even more preferably 75/25 or more from the viewpoint of low-temperature fixability. In the above calculation, the mass of the polyester resin is the mass of the raw material monomer of the polyester resin used minus the amount of reaction water dehydrated by the polycondensation reaction (calculated value), and the amount of the bireactive monomer is included in the amount of raw material monomer of the polyester resin. The amount of the styrene resin is the total amount of the raw material monomer of the styrene resin and the polymerization initiator.

The softening point of the amorphous composite resin AX is preferably 90°C or higher, more preferably 100°C or higher, from the viewpoint of heat resistance storage stability, and is preferably 150°C or lower, more preferably 140°C or lower, from the viewpoint of low-temperature fixability.

The glass transition temperature of the amorphous composite resin AX is preferably 45°C or higher, more preferably 50°C or higher, from the viewpoint of heat resistance storage stability, and is preferably 70°C or lower, more preferably 65°C or lower, from the viewpoint of low-temperature fixability.

The weight average molecular weight of the amorphous composite resin AX is preferably 3,000 or more, more preferably 4,000 or more, from the viewpoint of heat resistance storage stability, and is preferably 150,000 or less, more preferably 125,000 or less, from the viewpoint of low temperature fixability.

The content of the amorphous composite resin AX in the binder resin is preferably 10% by mass or more, more preferably 20% by mass or more, and even more preferably 25% by mass or more, from the viewpoint of low-temperature fixability, and is preferably 80% by mass or less, more preferably 70% by mass or less, and even more preferably 65% by mass or less, from the viewpoint of durability.

The binder resin of the first embodiment preferably further contains an amorphous composite resin AX and an amorphous polyester resin B1 that does not contain hydrogenated terpene phenol resin, i.e., an amorphous polyester resin B1 that is a polycondensate of raw material monomers for polyester resin and is not a resin obtained using hydrogenated terpene phenol resin.

Amorphous polyester resin B1 may be a resin with a lower or higher softening point than amorphous composite resin AX, but from the viewpoint of hot offset resistance, it is preferable that it is a resin with a higher softening point than amorphous composite resin AX (amorphous polyester resin BH1). The difference in softening point between amorphous composite resin AX and amorphous polyester resin B1 is preferably 15°C or more, more preferably 20°C or more, even more preferably 25°C or more, and is preferably 55°C or less, more preferably 50°C or less, even more preferably 45°C or less.

The softening point of the amorphous polyester resin BH1 is preferably 120°C or higher, more preferably 130°C or higher, from the viewpoint of hot offset resistance, and is preferably 160°C or lower, more preferably 150°C or lower, from the viewpoint of low-temperature fixing ability.

When amorphous polyester resin BH1 is contained, the softening point of amorphous composite resin AX is preferably 80°C or higher, more preferably 90°C or higher, from the viewpoint of heat-resistant storage stability, and is preferably 120°C or lower, more preferably 110°C or lower, from the viewpoint of low-temperature fixability.

Amorphous polyester resin BH1 is obtained using the same raw material monomers as those of the polyester resin in composite resin AX, except that the carboxylic acid component preferably contains an aromatic dicarboxylic acid compound and a trivalent or higher carboxylic acid compound.

The content of the aromatic dicarboxylic acid compound in the carboxylic acid component is preferably 20 mol% or more, more preferably 25 mol% or more, even more preferably 30 mol% or more, and is 100 mol% or less, preferably 70 mol% or less, more preferably 60 mol% or less, even more preferably 50 mol% or less.

The content of the trivalent or higher carboxylic acid compound in the carboxylic acid component is preferably 5 mol% or more, more preferably 10 mol% or more, even more preferably 15 mol% or more, and is preferably 40 mol% or less, more preferably 35 mol% or less, even more preferably 30 mol% or less, from the viewpoint of adjusting the softening point.

The glass transition temperature of the amorphous polyester resin BH1 is preferably 45°C or higher, more preferably 50°C or higher, from the viewpoint of heat-resistant storage stability, and is preferably 70°C or lower, more preferably 65°C or lower, from the viewpoint of low-temperature fixability.

The weight average molecular weight of the amorphous polyester resin BH1 is preferably 10,000 or more, more preferably 30,000 or more, from the viewpoint of hot offset resistance, and is preferably 300,000 or less, more preferably 200,000 or less, from the viewpoint of low-temperature fixability.

The content of amorphous polyester resin B1 in the binder resin is preferably 10% by mass or more, more preferably 15% by mass or more, and even more preferably 20% by mass or more, from the viewpoint of low-temperature fixability, and is preferably 80% by mass or less, more preferably 75% by mass or less, and even more preferably 70% by mass or less, from the viewpoint of durability.

The mass ratio of amorphous composite resin AX to amorphous polyester resin B1 (amorphous composite resin AX/amorphous polyester resin B1) is preferably 10/90 or more, more preferably 15/85 or more, even more preferably 20/80 or more, and is preferably 80/20 or less, more preferably 75/25 or less, even more preferably 70/30 or less.

From the viewpoint of low-temperature fixability, it is preferable that the binder resin of the first embodiment further contains crystalline polyester resin C1.

As the crystalline polyester resin C1, a polycondensation product of an alcohol component containing an aliphatic diol and a carboxylic acid component containing an aliphatic dicarboxylic acid compound is preferable.

Examples of aliphatic diols include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,7-heptanediol, 1,8-octanediol, neopentyl glycol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, and 1,12-dodecanediol.

The carbon number of the aliphatic diol is preferably 2 or more, more preferably 4 or more, and preferably 12 or less, more preferably 10 or less, from the viewpoint of adequate compatibility with the amorphous polyester.

In addition, from the viewpoint of improving the low-temperature fixing property of the toner, it is preferable that the aliphatic diol has a hydroxyl group at the end of the carbon chain, and it is more preferable that the aliphatic diol is an α,ω-linear alkane diol.

The content of the aliphatic diol in the alcohol component is preferably 80 mol% or more, more preferably 90 mol% or more, even more preferably 95 mol% or more, and 100 mol% or less. When the alcohol component contains a monoalcohol, it is preferably 98 mol% or less, more preferably 95 mol% or less.

Other alcohol components include aromatic diols such as alkylene oxide adducts of bisphenol A, and trihydric or higher alcohols such as glycerin.

Examples of aliphatic dicarboxylic acid compounds include succinic acid (carbon number: 4), fumaric acid (carbon number: 4), adipic acid (carbon number: 6), suberic acid (carbon number: 8), azelaic acid (carbon number: 9), sebacic acid (carbon number: 10), dodecanedioic acid (carbon number: 12), tetradecanedioic acid (carbon number: 14), succinic acid having an alkyl or alkenyl group on the side chain, anhydrides of these acids, and alkyl esters of these acids having 1 to 3 carbon atoms. Here, when the aliphatic dicarboxylic acid compound is an alkyl ester, the number of carbon atoms of the alkyl group is not included in the above carbon number.

From the viewpoint of hydrophobicity, the carbon number of the aliphatic dicarboxylic acid compound is preferably 4 or more, more preferably 8 or more, even more preferably 10 or more, and even more preferably 12 or more, and from the viewpoint of low-temperature fixability, it is preferably 16 or less, more preferably 14 or less.

The aliphatic dicarboxylic acid compound may be a saturated aliphatic dicarboxylic acid compound or an unsaturated aliphatic dicarboxylic acid compound, but from the viewpoint of durability, it is preferable that it is a saturated aliphatic dicarboxylic acid compound.

From the viewpoint of durability, the content of the aliphatic dicarboxylic acid compound in the carboxylic acid component is preferably 65 mol% or more, more preferably 70 mol% or more, even more preferably 75 mol% or more, and 100 mol% or less. When the carboxylic acid component contains a monocarboxylic acid compound, the content is preferably 98 mol% or less, more preferably 95 mol% or less.

Other carboxylic acid components include aromatic dicarboxylic acid compounds such as phthalic acid, isophthalic acid, and terephthalic acid, and trivalent or higher carboxylic acid compounds such as trimellitic acid and pyromellitic acid.

Furthermore, the alcohol component and/or carboxylic acid component of the crystalline polyester resin C1 preferably contains a monofunctional monomer from the viewpoint of achieving adequate compatibility with the amorphous polyester.

Examples of monofunctional monomers contained in the alcohol component include aliphatic monoalcohols such as capric alcohol, lauryl alcohol, myristyl alcohol, palmityl alcohol, stearyl alcohol, and behenyl alcohol.

Examples of monofunctional monomers contained in the carboxylic acid component include aliphatic monocarboxylic acids such as capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, and behenic acid, and aliphatic monocarboxylic acid compounds such as alkyl esters of these acids in which the alkyl group has 1 to 3 carbon atoms.

From the viewpoint of hydrophobicity, it is preferable that the monofunctional monomer contains an aliphatic monocarboxylic acid compound and/or an aliphatic monoalcohol.

From the viewpoint of hydrophobicity, the carbon number of the aliphatic monoalcohol is preferably 10 or more, more preferably 12 or more, and even more preferably 14 or more, and from the viewpoint of low-temperature fixability, it is preferably 22 or less, more preferably 20 or less, and even more preferably 18 or less.

The carbon number of the aliphatic monocarboxylic acid compound is preferably 10 or more, more preferably 12 or more, from the viewpoint of hydrophobicity, and is preferably 22 or less, more preferably 20 or less, and even more preferably 18 or less, from the viewpoint of low-temperature fixability. Here, when the aliphatic monocarboxylic acid compound is an alkyl ester, the carbon number of the alkyl group is not included in the above carbon number.

The content of monofunctional monomers in the raw material monomers (the total amount of alcohol components and carboxylic acid components) is preferably 1 mol% or more, more preferably 3 mol% or more, and even more preferably 5 mol% or more, and from the viewpoint of low-temperature fixability, is preferably 30 mol% or less, more preferably 20 mol% or less, and even more preferably 15 mol% or less.

The equivalent ratio of the carboxyl groups of the carboxylic acid component to the hydroxyl groups of the alcohol component (COOH groups/OH groups) is preferably 0.8 or more, more preferably 0.9 or more, from the viewpoint of durability, and is preferably 1.2 or less, more preferably 1.1 or less, from the viewpoint of low-temperature fixability.

The polycondensation reaction conditions of the alcohol component and the carboxylic acid component of the crystalline polyester resin C1 are similar to the reaction conditions of the raw material monomers of the polyester resin of the amorphous composite resin AX, except that the suitable reaction temperature is preferably 120°C or higher, more preferably 180°C or higher, and preferably 230°C or lower, more preferably 220°C or lower.

From the viewpoint of durability, the softening point of the crystalline polyester resin C1 is preferably 50°C or higher, more preferably 65°C or higher, and even more preferably 70°C or higher, and from the viewpoint of low-temperature fixability, it is preferably 120°C or lower, and more preferably 110°C or lower.

The melting point of the crystalline polyester resin C1 is preferably 60°C or higher, more preferably 65°C or higher, from the viewpoint of durability, and is preferably 130°C or lower, more preferably 120°C or lower, from the viewpoint of low-temperature fixability.

The weight average molecular weight of the crystalline polyester resin C1 is preferably 3,000 or more, more preferably 5,000 or more, from the viewpoint of hot offset resistance, and is preferably 30,000 or less, more preferably 25,000 or less, from the viewpoint of low-temperature fixability.

The content of crystalline polyester resin C1 in the binder resin is preferably 3% by mass or more, more preferably 5% by mass or more, and even more preferably 7% by mass or more, from the viewpoint of low-temperature fixability, and is preferably 30% by mass or less, more preferably 25% by mass or less, and even more preferably 20% by mass or less, from the viewpoint of durability.

The mass ratio of the sum of amorphous composite resin AX and amorphous polyester resin B1 to crystalline polyester resin C1 (sum of amorphous composite resin AX and amorphous polyester resin B1/crystalline polyester resin C1) is preferably 70/30 or more, more preferably 75/25 or more, even more preferably 80/20 or more, and is preferably 97/3 or less, more preferably 95/5 or less, even more preferably 93/7 or less.

The total amount of amorphous composite resin AX, amorphous polyester resin B1, and crystalline polyester resin C1 in the binder resin is preferably 80% by mass or more, more preferably 90% by mass or more, even more preferably 95% by mass or more, and even more preferably 100% by mass.

In the second embodiment, the raw material monomers for the polyester resin are preferably an alcohol component containing an aliphatic diol and a carboxylic acid component containing an aliphatic dicarboxylic acid compound, similar to the crystalline polyester resin C1 in the first embodiment.

The hydrogenated terpene phenol resin is the same as in the first embodiment, and the polycondensate of the raw material monomers of the polyester resin and the hydrogenated terpene phenol resin is obtained by polycondensing the alcohol component and the carboxylic acid component as the raw material monomers of the polyester resin, using both the raw material monomers and the hydrogenated terpene phenol resin, and subjecting them to a polycondensation reaction, in the same manner as in the first embodiment.

From the viewpoint of durability, the softening point of the crystalline composite resin CX is preferably 50°C or higher, more preferably 65°C or higher, and even more preferably 70°C or higher, and from the viewpoint of low-temperature fixability, it is preferably 120°C or lower, and more preferably 110°C or lower.

From the viewpoint of durability, the melting point of the crystalline composite resin CX is preferably 55°C or higher, more preferably 60°C or higher, and from the viewpoint of low-temperature fixability, it is preferably 130°C or lower, more preferably 120°C or lower.

The weight average molecular weight of the crystalline composite resin CX is preferably 3,000 or more, more preferably 5,000 or more, from the viewpoint of hot offset resistance, and is preferably 30,000 or less, more preferably 25,000 or less, from the viewpoint of low-temperature fixing property.

The content of crystalline composite resin CX in the binder resin is preferably 5% by mass or more, more preferably 10% by mass or more, and even more preferably 15% by mass or more, from the viewpoint of low-temperature fixability, and is preferably 35% by mass or less, more preferably 30% by mass or less, and even more preferably 25% by mass or less, from the viewpoint of durability.

From the viewpoint of charging stability, it is preferable that the binder resin of the second embodiment further contains an amorphous polyester resin B2 composed of multiple resins with different softening points.

The amorphous polyester resin BL2, which has a lower softening point, is obtained by polycondensing an alcohol component and a carboxylic acid component in the same manner as the amorphous composite resin AX, except that no hydrogenated terpene phenol resin is used, and the amorphous polyester resin BH2, which has a higher softening point, is the same as the amorphous polyester resin BH1 in the first embodiment.

The difference in softening point between the amorphous polyester resins BL2 and BH2 is preferably 15°C or more, more preferably 20°C or more, even more preferably 25°C or more, and is preferably 60°C or less, more preferably 55°C or less, even more preferably 50°C or less.

The softening point of the amorphous polyester resin BL2 is preferably 80°C or higher, more preferably 90°C or higher, and preferably 120°C or lower, more preferably 110°C or lower.

The glass transition temperature and weight average molecular weight of amorphous polyester resin BL2 are the same as those of amorphous composite resin AX.

The softening point of the amorphous polyester resin BH2 is preferably 120°C or higher, more preferably 130°C or higher, and preferably 160°C or lower, more preferably 150°C or lower.

The glass transition temperature and weight average molecular weight of amorphous polyester resin BH2 are the same as those of amorphous polyester resin BH1.

The mass ratio of amorphous polyester resin BL2 to amorphous polyester resin BH2 (amorphous polyester resin BL2/amorphous polyester resin BH2) is preferably 50/50 or more, more preferably 55/45 or more, even more preferably 60/40 or more, and is preferably 85/15 or less, more preferably 80/20 or less, even more preferably 75/25 or less.

The content of amorphous polyester resin B2 in the binder resin is preferably 65% by mass or more, more preferably 70% by mass or more, and even more preferably 75% by mass or more, from the viewpoint of low-temperature fixability, and is preferably 95% by mass or less, more preferably 90% by mass or less, and even more preferably 85% by mass or less, from the viewpoint of durability.

The mass ratio of crystalline composite resin CX to amorphous polyester resin B2 (crystalline composite resin CX/amorphous polyester resin B2) is preferably 5/95 or more, more preferably 10/90 or more, even more preferably 15/85 or more, and is preferably 35/65 or less, more preferably 30/70 or less, even more preferably 25/75 or less.

Examples of binder resins other than the composite resin X and polyester resin include vinyl resins such as styrene-acrylic resins, epoxy resins, polycarbonates, polyurethanes, composite resins containing two or more of these resins, etc.

The content of the binder resin in the toner is preferably 50% by mass or more, more preferably 60% by mass or more, even more preferably 70% by mass or more, even more preferably 80% by mass or more, and preferably 99% by mass or less, more preferably 98% by mass or less, even more preferably 95% by mass or less.

Examples of release agents include hydrocarbon waxes such as polypropylene wax, polyethylene wax, polypropylene-polyethylene copolymer wax, microcrystalline wax, paraffin wax, and Fischer-Tropsch wax, and oxides thereof; ester waxes such as carnauba wax, montan wax, and deacidified waxes thereof, and fatty acid ester wax; fatty acid amides, fatty acids, higher alcohols, and fatty acid metal salts; and the like, which can be used alone or in combination of two or more.

The melting point of the release agent is preferably 60°C or higher, more preferably 70°C or higher, from the viewpoint of toner transferability, and is preferably 160°C or lower, more preferably 140°C or lower, even more preferably 120°C or lower, and even more preferably 110°C or lower, from the viewpoint of low-temperature fixability.

The content of the release agent is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, and even more preferably 1.5 parts by mass or more, relative to 100 parts by mass of the binder resin, from the viewpoints of the low-temperature fixability and offset resistance of the toner and the dispersibility in the binder resin, and is preferably 10 parts by mass or less, more preferably 8 parts by mass or less, and even more preferably 7 parts by mass or less.

The toner for developing electrostatic images of the present invention may contain additives such as colorants, charge control agents, magnetic powders, flowability improvers, conductivity regulators, reinforcing fillers such as fibrous substances, antioxidants, and cleaning improvers, in addition to the binder resin and release agent.

As colorants, dyes, pigments, magnetic materials, etc. used as toner colorants can be used. Examples include carbon black, phthalocyanine blue, permanent brown FG, brilliant fast scarlet, pigment red 122, pigment green B, rhodamine B base, solvent red 49, solvent red 146, solvent blue 35, quinacridone, carmine 6B, isoindoline, disazo yellow, etc. In the present invention, the toner may be either a black toner or a color toner.

From the viewpoint of improving the image density and low-temperature fixability of the toner, the content of the colorant is preferably 1 part by mass or more, more preferably 2 parts by mass or more, and preferably 40 parts by mass or less, more preferably 20 parts by mass or less, and even more preferably 10 parts by mass or less, per 100 parts by mass of the binder resin.

The charge control agent is not particularly limited, and may contain either a positively charged charge control agent or a negatively charged charge control agent.

Positively charged charge control agents include nigrosine dyes such as "Nigrosine Base EX", "Oil Black BS", "Oil Black SO", "Bontron N-01", "Bontron N-04", "Bontron N-07", "Bontron N-09", and "Bontron N-11" (all manufactured by Orient Chemical Industries Co., Ltd.); triphenylmethane dyes containing a tertiary amine as a side chain; quaternary ammonium salt compounds such as "Bontron P-51" (manufactured by Orient Chemical Industries Co., Ltd.), cetyltrimethylammonium bromide, and "COPY CHARGE PX VP435 (Clariant), etc.; polyamine resins, such as AFP-B (Orient Chemical Industries, Ltd.); imidazole derivatives, such as PLZ-2001 and PLZ-8001 (both manufactured by Shikoku Chemical Industries, Ltd.); styrene-acrylic resins, such as FCA-701PT and FCA-201-PS (Fujikura Chemical Industries, Ltd.), etc.

Examples of negatively charged charge control agents include metal-containing azo dyes, such as "Varifast Black 3804", "Bontron S-31", "Bontron S-32", "Bontron S-34", and "Bontron S-36" (all manufactured by Orient Chemical Industry Co., Ltd.), "Aizen Spiron Black TRH", and "T-77" (manufactured by Hodogaya Chemical Co., Ltd.); metal compounds of benzilic acid compounds, such as "LR-147" and "LR-297" (both manufactured by Nippon Carlit Co., Ltd.); metal compounds of salicylic acid compounds, such as "Bontron E-81", "Bontron E-84", "Bontron E-88", and "Bontron E-304" (all manufactured by Orient Chemical Industry Co., Ltd.), and "TN-105" (manufactured by Hodogaya Chemical Co., Ltd.); copper phthalocyanine dyes; and quaternary ammonium salts, such as "COPY CHARGE NX VP434 (Clariant), nitroimidazole derivatives, etc.; organometallic compounds, etc.

From the viewpoint of the charge stability of the toner, the content of the charge control agent is preferably 0.01 parts by mass or more, more preferably 0.2 parts by mass or more, and preferably 10 parts by mass or less, more preferably 5 parts by mass or less, even more preferably 3 parts by mass or less, and even more preferably 2 parts by mass or less, per 100 parts by mass of the binder resin.

The toner of the present invention may be obtained by any of the conventionally known methods such as a melt-kneading method, an emulsion phase inversion method, a polymerization method, etc., but from the viewpoint of dispersibility of the release agent, a pulverized toner obtained by a melt-kneading method is preferred. In the case of a pulverized toner obtained by a melt-kneading method, for example,
The toner can be obtained by a method including: step 1: a step of melt-kneading at least a binder resin and a release agent; and step 2: a step of pulverizing and classifying the melt-kneaded product obtained in step 1.

The mixture to be melt-kneaded may be kneaded all at once or in portions, but it is preferable to mix the mixture in advance in a mixer such as a Henschel mixer or ball mill and then feed it to the kneader.

Melt kneading can be carried out using a known kneading machine such as an internal kneader, a single-screw or twin-screw extruder, or an open roll type kneader, but from the viewpoint of dispersibility of the release agent, it is preferable to use a twin-screw extruder.

After step 1, the kneaded material is cooled appropriately until it reaches a crushable hardness, and then step 2 is carried out. Here, cooling refers to cooling the kneaded material to a temperature between 0°C and 50°C, or to a temperature below the glass transition temperature of the binder resin in the kneaded material.

In step 2, the molten mixture obtained in step 1 may be crushed to the desired particle size all at once or in stages, but from the viewpoint of efficient and more uniform crushing, it is preferable to perform the crushing in two stages: coarse crushing and fine crushing.

Mills used for coarse grinding include hammer mills, cutter mills, atomizers, and rotoplexes.

Mills used for fine grinding include jet mills such as fluidized bed jet mills and collision plate jet mills, mechanical mills, etc.

It is preferable to adjust the degree of pulverization appropriately depending on the particle size of the desired toner particles.

Classifiers used for classification include airflow classifiers, inertial classifiers, and sieve classifiers. During classification, pulverized material that is removed due to insufficient pulverization may be subjected to pulverization again, and pulverization and classification may be repeated as necessary.

In order to improve the transferability of the toner of the present invention, it is preferable to use an external additive. Examples of external additives include inorganic fine particles such as silica, alumina, titania, zirconia, tin oxide, and zinc oxide, and organic fine particles such as resin particles such as melamine-based resin fine particles and polytetrafluoroethylene resin fine particles, and two or more types may be used in combination. Among these, silica is preferable, and from the viewpoint of the transferability of the toner, hydrophobic silica that has been hydrophobized is more preferable.

Hydrophobic treatment agents for hydrophobizing the surface of silica particles include hexamethyldisilazane (HMDS), dimethyldichlorosilane (DMDS), cyclic silazane, silicone oil, aminosilane, octyltriethoxysilane (OTES), methyltriethoxysilane, etc.

From the viewpoint of the chargeability, fluidity, and transferability of the toner, the average particle size of the external additive is preferably 10 nm or more, more preferably 15 nm or more, and is preferably 250 nm or less, more preferably 200 nm or less, and even more preferably 90 nm or less.

The external addition process by mixing the toner particles with the external additives can be carried out according to conventional methods, and a mixer such as a Henschel mixer can be used.

From the viewpoint of the chargeability, fluidity, and transferability of the toner, the content of the external additive is preferably 0.05 parts by mass or more, more preferably 0.1 parts by mass or more, and even more preferably 0.3 parts by mass or more, per 100 parts by mass of the toner particles before treatment with the external additive, and is preferably 5 parts by mass or less, and more preferably 4 parts by mass or less.

The volume median particle diameter ( _D50 ) of the toner of the present invention is preferably 3 μm or more, more preferably 4 μm or more, and preferably 15 μm or less, more preferably 10 μm or less. In this specification, the volume median particle diameter ( _D50 ) means a particle diameter at which the cumulative volume frequency calculated by volume fraction is 50% calculated from the smallest particle diameter. In addition, when the toner is treated with an external additive, the volume median particle diameter of the toner particles before treatment with the external additive is taken as the volume median particle diameter of the toner.

The toner of the present invention can be used as it is as a single-component developing toner, or mixed with a carrier as a two-component developing toner, in image forming devices using either a single-component developing method or a two-component developing method.

The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. The physical properties of the resins and the like can be measured by the following methods.

[Softening point of resin (Tm)]
Using a flow tester "CFT-500D" (Shimadzu Corporation), 1g of sample is heated at a temperature increase rate of 6℃/min while applying a load of 1.96MPa with the plunger, and extruding the sample from a nozzle with a diameter of 1mm and length of 1mm. The amount of plunger descent of the flow tester is plotted against the temperature, and the temperature at which half of the sample has flowed out is taken as the softening point.

[Maximum endothermic peak temperature of resin]
Using a differential scanning calorimeter "Q-20" (TA Instruments Japan, Inc.), 0.01-0.02 g of sample is weighed into an aluminum pan and cooled from room temperature (25°C) to 0°C at a rate of 10°C/min, and maintained at 0°C for 1 minute. Then, measure at a rate of 10°C/min. The temperature of the peak with the largest peak area among the observed endothermic peaks is regarded as the maximum endothermic peak temperature. For crystalline resins, the maximum endothermic peak temperature is regarded as the melting point.

[Glass transition temperature (Tg) of resin]
Using a differential scanning calorimeter "Q-20" (manufactured by TA Instruments Japan), 0.01 to 0.02 g of sample is weighed into an aluminum pan and heated from room temperature (25°C) to 200°C at a heating rate of 10°C/min, then cooled from that temperature to 0°C at a heating rate of 10°C/min. The sample is then heated at a heating rate of 10°C/min, and the endothermic peak is measured. The glass transition temperature is the temperature at the intersection of an extension of the baseline below the maximum endothermic peak temperature and a tangent line showing the maximum slope from the rising part of the peak to the top of the peak.

[Hydroxyl value (OHV) of resin]
Measure based on the method of JIS K 0070:1992, except that the measurement solvent is changed from the mixed solvent of ethanol and ether specified in JIS K 0070 to tetrahydrofuran.

[Weight average molecular weight (Mw) of resin]
The weight average molecular weight is determined by gel permeation chromatography (GPC) according to the following method.
(1) Preparation of sample solution Dissolve the sample in tetrahydrofuran (amorphous resin) or chloroform (crystalline resin) at 40°C to a concentration of 0.5 g/100 mL. Next, filter this solution using a fluororesin filter "DISMIC-25JP" (manufactured by ADVANTEC) with a pore size of 0.2 μm (for amorphous polyester resin) or a fluororesin filter "FP-200" (manufactured by Sumitomo Electric Industries, Ltd.) with a pore size of 2 μm (for crystalline polyester resin) to remove insoluble matter, and use this as the sample solution.
(2) Molecular weight measurement Using the following measurement equipment and analytical column, tetrahydrofuran (amorphous resin) or chloroform (crystalline resin) is passed as the eluent at a flow rate of 1 mL per minute, and the column is stabilized in a thermostatic bath at 40°C. 100 μL of the sample solution is injected into the column and measurement is performed. The molecular weight of the sample is calculated based on a calibration curve prepared in advance. The calibration curve used here was prepared using several types of monodisperse polystyrene (A-500 (5.0×10 ² ), A-1000 (1.01×10 ³ ), A-2500 (2.63×10 ³ ), A-5000 (5.97×10 ³ ), F-1 (1.02×10 ⁴ ), F-2 (1.81×10 ⁴ ), F-4 (3.97×10 ⁴ ), F-10 (9.64×10 ⁴ ), F-20 (1.90×10 ⁵ ), F-40 (4.27×10 ⁵ ), F-80 (7.06×10 ⁵ ), F-128 (1.09×10 ⁶ ) manufactured by Tosoh Corporation) as standard samples. The molecular weight is indicated in parentheses.
Measuring device: "HLC-8220CPC" (manufactured by Tosoh Corporation) (for amorphous polyester resin) or "CO-8010" (manufactured by Tosoh Corporation) (for crystalline polyester resin)
Analytical column: TSKgel GMH _XL + TSKgel G3000H _XL (manufactured by Tosoh Corporation)

[Melting point of release agent]
Using a differential scanning calorimeter "Q-20" (manufactured by TA Instruments Japan Co., Ltd.), 0.01 to 0.02 g of the sample is weighed into an aluminum pan, heated to 200°C at a heating rate of 10°C/min, and cooled from that temperature to -10°C at a heating rate of 5°C/min. Next, the sample is heated to 180°C at a heating rate of 10°C/min and measured. The maximum endothermic peak temperature observed from the melting endothermic curve obtained is regarded as the melting point of the release agent.

[Average particle size of external additives]
The average particle size refers to the number-average particle size, and is calculated by measuring the particle sizes (average of major and minor axes) of 500 particles in a scanning electron microscope (SEM) photograph and averaging these by number.

[Volume Median Particle Size of Toner]
- Measuring instrument: Coulter Multisizer III (manufactured by Beckman Coulter, Inc.)
Aperture diameter: 50 μm
・Analysis software: Multisizer III version 3.51 (Beckman Coulter, Inc.)
・Electrolyte: "Isoton (registered trademark) II" (Beckman Coulter, Inc.)
Dispersion: Polyoxyethylene lauryl ether "EMULGEN (registered trademark) 109P" (manufactured by Kao Corporation, HLB (Griffin) = 13.6) was dissolved in the electrolyte to adjust the concentration to 5% by mass. Dispersion conditions: 10 mg of a measurement sample was added to 5 mL of the dispersion and dispersed for 1 minute using an ultrasonic disperser (machine name: US-1, manufactured by SND Corporation, output: 80 W). Thereafter, 25 mL of electrolyte was added and the mixture was further dispersed for 1 minute using the ultrasonic disperser to prepare a sample dispersion.
Measurement conditions: The sample dispersion is added to 100 mL of the electrolyte to adjust the concentration to a level that allows the particle size of 30,000 particles to be measured in 20 seconds, and then the 30,000 particles are measured and the volume median particle size ( _D50 ) is calculated from the particle size distribution.

Resin Production Example 1
The alcohol component, carboxylic acid component, esterification catalyst, esterification promoter, and hydrogenated terpene phenol resin (not used in resin B1) shown in Tables 1 and 2 were placed in a 10-liter four-neck flask equipped with a thermometer, a stainless steel stirring rod, a dehydration tube, a cooling tube, and a nitrogen inlet tube, and the temperature was raised to 235°C over 2 hours in a nitrogen atmosphere in a mantle heater. Thereafter, polycondensation reaction was carried out at 235°C for 8 hours, and the reaction was continued until the desired softening point was reached at 8 kPa, to obtain amorphous composite resins (resins A1, A5, A6) and amorphous polyester resin (resin B1).

Resin Production Example 2
The raw material monomers, esterification catalyst, esterification promoter, and hydrogenated terpene phenol resin shown in Table 1 were placed in a 10-liter four-neck flask equipped with a thermometer, a stainless steel stirring rod, a dehydration tube, a cooling tube, and a nitrogen inlet tube, and the temperature was raised to 235 ° C. in a mantle heater in a nitrogen atmosphere over 2 hours. Then, polycondensation reaction was carried out at 235 ° C. for 8 hours, and further reaction was carried out at 230 ° C. and 8.0 kPa for 1 hour. After cooling to 160 ° C., a mixed solution of raw material monomers, bireactive monomers, and polymerization initiators for styrene-based resins shown in Table 1 was dropped over 1 hour. Then, after keeping at 160 ° C. for 30 minutes, the temperature was raised to 200 ° C., and further reaction was carried out under reduced pressure of 40 kPa until the desired softening point was reached, to obtain an amorphous composite resin (resin A2).

Resin Production Example 3
The alcohol components shown in Tables 1 and 2, carboxylic acid components other than adipic acid and trimellitic anhydride, esterification catalyst, esterification promoter, and hydrogenated terpene phenol resin (only resin A3 used) were placed in a 10-liter four-neck flask equipped with a thermometer, a stainless steel stirring rod, a dehydration tube, a cooling tube, and a nitrogen inlet tube, and the temperature was raised to 235 ° C. over 2 hours in a mantle heater in a nitrogen atmosphere. After that, it was confirmed that the reaction rate reached 95% at 235 ° C., and the mixture was cooled to 180 ° C., and then adipic acid and trimellitic anhydride shown in Tables 1 and 2 were added, and the temperature was raised to 220 ° C. over 2 hours. After that, the mixture was reacted at 220 ° C. for 1 hour, and then reacted at 8 kPa until the desired softening point was reached, to obtain an amorphous composite resin (resin A3) and an amorphous polyester resin (resin B2). In addition, the reaction rate in this specification refers to the value of the amount of water produced by reaction (mol) / theoretical amount of water produced (mol) × 100.

Resin Production Example 4
The alcohol component, carboxylic acid component, esterification catalyst, and hydrogenated terpene phenol resin shown in Table 1 were placed in a 10-liter four-neck flask equipped with a thermometer, a stainless steel stirring rod, a fractionating column, a dehydration tube equipped with a fractionating tube through which 100°C hot water was passed, a cooling tube, and a nitrogen inlet tube, and the mixture was kept at 180°C for 1 hour in a mantle heater in a nitrogen atmosphere, and then heated from 180°C to 230°C at a rate of 10°C/h. Thereafter, a polycondensation reaction was carried out at 230°C for 10 hours, and the reaction was continued at 8 kPa until the desired softening point was reached, to obtain an amorphous composite resin (resin A4).

Resin Production Example 5
The alcohol component, carboxylic acid component, esterification catalyst, esterification promoter, and terpene phenol resin shown in Table 2 were placed in a 10-liter four-neck flask equipped with a thermometer, a stainless steel stirring rod, a dehydration tube, a cooling tube, and a nitrogen inlet tube, and the temperature was raised to 235°C over 2 hours in a nitrogen atmosphere in a mantle heater. Thereafter, polycondensation reaction was carried out at 235°C for 8 hours, and the reaction was continued at 8 kPa until the desired softening point was reached, to obtain an amorphous resin (resin B3). However, it is presumed that non-hydrogenated terpene phenol resin is difficult to composite with polyester resin because the reactivity of the phenolic hydroxyl group to esterification is extremely low.

Resin Production Example 6
The alcohol component, carboxylic acid component, esterification catalyst, and hydrogenated terpene phenol resin (not used in Resin C2) shown in Table 3 were placed in a 10-liter four-neck flask equipped with a thermometer, a stainless steel stirring rod, a dehydration tube, a cooling tube, and a nitrogen inlet tube, and the mixture was kept at 140° C. for 1 hour in a nitrogen atmosphere in a mantle heater, and then heated from 140° C. to 200° C. at a rate of 10° C./h. Thereafter, polycondensation reaction was carried out at 200° C. for 1 hour, and further reaction was carried out at 200° C. and 8.0 kPa until the desired softening point was reached, to obtain a crystalline composite resin (Resin C1) and a crystalline polyester resin (Resin C2).

Examples 1 to 7 and Comparative Examples 1 to 4
100 parts by mass of the binder resin shown in Table 4, 1 part by mass of the negative charge control agent "Bontron E-81" (manufactured by Orient Chemical Industry Co., Ltd.), 5 parts by mass of the colorant "Pigment blue 15:3" (manufactured by Dainichi Seika Chemical Industry Co., Ltd., phthalocyanine blue), and 2 parts by mass of the release agent "HNP-9" (manufactured by Nippon Seiro Co., Ltd., paraffin wax, melting point: 75°C) were thoroughly mixed in a Henschel mixer, and then melt-kneaded at a roll rotation speed of 200 r/min and a heating temperature inside the roll of 100°C using a co-rotating twin-screw extruder with a kneading section having a total length of 1560 mm, a screw diameter of 42 mm, and a barrel inner diameter of 43 mm. The feed rate of the mixture was 20 kg/h, and the average residence time was about 18 seconds. The resulting molten kneaded product was cooled and coarsely pulverized, and then pulverized in a jet mill and classified to obtain toner particles having a volume median particle size (D ₅₀ ) of 8 μm.

1.0 part by mass of hydrophobic silica "AEROSIL NAX 50" (manufactured by Nippon Aerosil Co., Ltd., hydrophobic treatment agent: HMDS, average particle size: approximately 30 nm) was added as an external additive to 100 parts by mass of the obtained toner particles, and the mixture was mixed in a Henschel mixer to obtain a toner.

Test Example 1 [Abrasion resistance]
Using "Business4200" (weight 105g/ ^m2 , manufactured by Xerox) as the evaluation paper, a solid image with a toner amount of 0.50mg/ ^cm2 was passed through a fixing device adjusted to 180°C to be fixed. The fixed image was left for one month in an environment of 40°C and 80% relative humidity. The fixed image after leaving was rubbed five times back and forth with a sand eraser with a bottom surface of 15mm x 7.5mm and a load of 500g, and the optical reflection density before and after rubbing was measured using a reflection densitometer "RD-915" (manufactured by Macbeth Co., Ltd.), and the reduction rate (%) of the image density was calculated from (1-(reflection density after rubbing/reflection density before rubbing)) x 100 to evaluate the abrasion resistance of the fixed image. The results are shown in Table 4.

Test Example 2 [Durability]
The toner was loaded onto a printing machine, Page Presto N-4 (Casio Computer Co., Ltd., fixing: contact fixing method, development: non-magnetic one-component development method, development roll diameter: 2.3 cm), and a diagonal stripe pattern with a blackening rate of 5.5% was continuously printed in an environment of 32°C temperature and 85% relative humidity. During the printing, a solid black image was printed every 500 sheets, and the presence or absence of streaks on the image was checked. Printing was stopped when streaks appeared on the image, and was continued up to a maximum of 9,000 sheets.
The number of printed sheets until streaks were visually observed on the image was regarded as the number of sheets on which streaks occurred due to toner melting and adhering to the developing roll, and durability was evaluated. In other words, the more sheets on which streaks did not occur, the higher the durability of the toner was judged to be. The results are shown in Table 4. In the table, ">9000" means that no streaks occurred even on the 9000th printed sheet.

From the above results, it can be seen that the toners of Examples 1 to 7 have good abrasion resistance and durability, in comparison with Comparative Examples 1 and 2 in which a terpene phenol resin or a hydrogenated terpene phenol resin was melt-mixed with a polyester resin, Comparative Example 3 in which a hydrogenated terpene phenol resin was not used, and Comparative Example 4 in which a resin obtained by using a terpene phenol resin together with raw material monomers for a polyester resin was used.
In addition, since the evaluation results of the toner of Comparative Example 1 in which polyester resin was kneaded with terpene phenol resin and the toner of Comparative Example 4 in which a polyester resin was synthesized in the presence of terpene phenol resin were almost the same, it is presumed that the resin used in Comparative Example 4 (resin B3) is not a composite resin of polyester resin and terpene phenol resin. This result is consistent with the presumption that it is difficult to composite non-hydrogenated terpene phenol resin with polyester resin.

The toner for developing electrostatic images of the present invention is suitable for use in developing latent images formed in electrostatic image developing methods, electrostatic recording methods, electrostatic printing methods, etc.

Claims (4)

A toner for developing electrostatic images containing a binder resin and a release agent, the binder resin containing composite resin X containing a raw material monomer for polyester resin and a polycondensate of hydrogenated terpene phenol resin. The toner for developing electrostatic images according to claim 1, wherein the mass ratio of the hydrogenated terpene phenol resin to the raw material monomer of the polyester resin in the composite resin X is 5/95 or more and 40/60 or less. The toner for developing electrostatic images according to claim 1 or 2, wherein composite resin X is an amorphous resin. A method for producing a toner for developing electrostatic images, comprising the steps of: a binder resin and a release agent; and a composite resin X including a polycondensate of a raw material monomer for a polyester resin and a hydrogenated terpene phenol resin, the method comprising the steps of:
A method for producing a toner for developing an electrostatic image, comprising: step 1: a step of melting and kneading at least the binder resin and the release agent; and step 2: a step of pulverizing and classifying the melt-kneaded product obtained in step 1.