Method for producing toner for electrostatic charge image development

Abstract

To provide a method for manufacturing a toner for electrostatic charge image development which is excellent in low temperature fixability and durability.SOLUTION: There is provided a method for manufacturing a toner for electrostatic charge image development containing a crystalline polyester resin C, an amorphous resin A, and a release agent, wherein the crystalline polyester resin C is a polycondensate of an alcohol component containing aliphatic diol having 8 to 10 carbon atoms, and a carboxylic acid component containing an aliphatic dicarboxylic compound having 6 to 10 carbon atoms; the method includes a step of melt-kneading a mixture containing the crystalline polyester resin C, the amorphous resin A and the release agent using an open roll type biaxial kneader having two rolls having different peripheral speeds; and the temperature on the discharge side of the kneaded product of a high rotation roll of the open roll type biaxial kneader is -20°C or higher and +15°C or lower than the melting point of the crystalline polyester resin C.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a method for manufacturing an electrostatic charge image developing toner used for developing a latent image formed in an electrophotographic method, an electrostatic recording method, an electrostatic printing method, or the like.

Background Art

[0002] As a binder resin for toner, it is known that a crystalline polyester resin is effective in improving the low-temperature fixability of toner, and its combined use with an amorphous resin has been studied.

[0003] Patent Document 1 discloses an electrostatic charge image developing toner containing an amorphous polyester resin A and a crystalline polyester resin C, wherein the amorphous polyester resin A has a constituent part derived from a polyester resin and a constituent part derived from a modified polyolefin polymer A having a reactive functional group, and the constituent part derived from the polyester resin and the constituent part derived from the modified polyolefin polymer A are linked via a covalent bond, and the amount of the constituent part derived from the modified polyolefin polymer A is 5% by mass or more and 30% by mass or less based on the total amount of the resin components in the toner.

[0004] Patent Document 2 discloses a toner containing a crystalline resin and an amorphous resin, wherein the ratio of the area of the region stained with ruthenium tetroxide in the reflected electron image of the cross-section of the toner stained with ruthenium tetroxide and photographed using a scanning electron microscope is 50% by area or more and 80% by area or less, and the ratio of the area of the region stained with ruthenium tetroxide in the reflected electron image of the surface of the toner stained with ruthenium tetroxide and photographed using a scanning electron microscope is 10% by area or more and 40% by area or less.

[0005] Patent Document 3 discloses a toner having a crystalline resin and an amorphous resin, wherein in X-ray diffraction measurement, diffraction peaks are present at least at positions of 2θ = 20° to 25°, and the difference between the glass transition temperature observed in the final heating step after heating and cooling under a predetermined heating and cooling condition 1 using a differential scanning calorimeter (DSC) and the glass transition temperature observed in the final heating step after heating and cooling under a predetermined heating and cooling condition 2 is within 10°C.

Prior Art Documents

Patent Documents

[0006]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0007] However, when manufacturing a pulverized toner using a crystalline polyester resin, if the crystalline polyester resin is not sufficiently dispersed in the amorphous resin by melt kneading, the dispersibility remains insufficient even after subsequent cooling and toner formation. As a result, the low-temperature fixability, which is a characteristic of the crystalline polyester resin, is not fully exhibited. Also, the crystalline polyester resin with reduced dispersibility seems to interfere with the dispersion of the release agent, resulting in inferior durability.

[0008] The present invention relates to a method for manufacturing an electrostatic charge image developing toner excellent in low-temperature fixability and durability.

Means for Solving the Problems

[0009] The present invention relates to a method for producing a toner for developing electrostatic images, which contains a crystalline polyester resin C, an amorphous resin A, and a release agent, the crystalline polyester resin C being a polycondensate of an alcohol component containing an aliphatic diol having from 8 to 10 carbon atoms and a carboxylic acid component containing an aliphatic dicarboxylic acid compound having from 6 to 10 carbon atoms, the method including a step of melt-kneading a mixture containing the crystalline polyester resin C, the amorphous resin A, and the release agent using an open-roll type twin-screw kneader equipped with two rolls having different peripheral speeds, the temperature of the kneaded product discharge side of the high-speed rotation roll of the open-roll type twin-screw kneader being from −20° C. to +15° C., which is the melting point of the crystalline polyester resin C. Effect of the Invention

[0010] The toner for developing electrostatic images obtained by the method of the present invention is excellent in terms of improving low-temperature fixing property and durability. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] The present invention has a major feature in that, when producing a toner for developing electrostatic images containing a crystalline polyester resin, an amorphous resin, and a release agent, the crystalline polyester resin is a polycondensate of raw material monomers including a specific aliphatic monomer, and an open-roll type twin-screw kneader in which a high-speed rotation roll is adjusted to a predetermined temperature is used in the melt-kneading step. The reason why the toner for developing electrostatic images obtained by the method of the present invention has excellent low-temperature fixing property and durability is not clear, but is presumed to be as follows.

[0012] In the present invention, by using an open roll type twin-screw kneader with high kneading strength and easy temperature control, the dispersibility of the crystalline polyester resin in the amorphous resin is improved. However, when using an open roll type twin-screw kneader for melt-kneading the raw material mixture, if the temperature on the discharge side of the kneaded material of the high-speed rotating roll is too low, a part of the crystalline polyester resin crystallizes during kneading, resulting in a decrease in dispersibility in the amorphous resin. On the other hand, even if the temperature on the discharge side of the kneaded material of the high-speed rotating roll is too high, the viscosity of the crystalline polyester resin decreases, resulting in a decrease in dispersibility in the amorphous resin, and in either case, it is not reflected in the improvement of low-temperature fixing property. Furthermore, it is considered that the durability also decreases because the crystalline polyester resin with reduced dispersibility hinders the dispersion of the release agent. In contrast, in the present invention, the temperature on the discharge side of the kneaded material of the open roll type twin-screw kneader is controlled near the melting point of the crystalline polyester resin. Furthermore, the crystalline polyester resin contains an aliphatic diol having 8 to 10 carbon atoms as an alcohol component and an aliphatic dicarboxylic acid-based compound having 6 to 10 carbon atoms as a carboxylic acid component, resulting in high hydrophobicity, and there is a crystalline polyester resin with improved dispersibility in the amorphous resin. Thus, it is considered that the dispersibility of the similarly hydrophobic release agent is also improved, and a toner excellent in low-temperature fixing property and durability is obtained.

[0013] In the present invention, the crystalline polyester resin C is a polycondensate of an alcohol component containing an aliphatic diol having 8 to 10 carbon atoms and a carboxylic acid component containing an aliphatic dicarboxylic acid-based compound having 6 to 10 carbon atoms.

[0014] The crystallinity of the resin is represented by a crystallinity index defined by the ratio of the softening point to the maximum peak temperature of endotherm measured by a differential scanning calorimeter, that is, the value of [softening point / maximum peak temperature of endotherm]. 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 one hand, the amorphous resin either has no observed endothermic peak, or if an endothermic peak is observed, it is a resin with a crystallinity index exceeding 1.4, preferably exceeding 1.5, more preferably 1.6 or higher, or a resin with a crystallinity index 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 manufacturing 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 taken as the melting point.

[0015] Examples of the aliphatic diol having 8 to 10 carbon atoms include 1,8 - octanediol, 1,9 - nonanediol, 1,10 - decanediol, etc.

[0016] The content of the aliphatic diol having 8 to 10 carbon atoms in the alcohol component is preferably 70 mol% or more, more preferably 80 mol% or more, still more preferably 90 mol% or more, still more preferably 95 mol% or more, and still more preferably 100 mol%.

[0017] Examples of the alcohol component other than the aliphatic diol having 8 to 10 carbon atoms include aliphatic diols having 7 or less carbon atoms such as 1,2 - propanediol, 1,3 - propanediol, 1,4 - butanediol, 1,5 - pentanediol, 1,6 - hexanediol, 1,7 - heptanediol, aliphatic diols having 11 or more carbon atoms, aromatic diols such as alkylene oxide adducts of bisphenol A, and polyhydric alcohols having 3 or more valences such as bisphenol A, hydrogenated bisphenol A, sorbitol, pentaerythritol, glycerin, trimethylolpropane, etc.

[0018] Examples of aliphatic dicarboxylic acid compounds having 6 to 10 carbon atoms include adipic acid (6 carbon atoms), suberic acid (8 carbon atoms), azelaic acid (9 carbon atoms), sebacic acid (10 carbon atoms), anhydrides of these acids, and alkyl esters of these acids having 1 to 3 carbon atoms in the alkyl group. When the aliphatic dicarboxylic acid compound is an alkyl ester, the number of carbon atoms in the alkyl group is not included in the above number of carbon atoms.

[0019] The content of the aliphatic dicarboxylic acid compound having 6 to 10 carbon atoms is preferably 70 mol% or more, more preferably 80 mol% or more, still more preferably 90 mol% or more, still more preferably 95 mol% or more, and still more preferably 100 mol% in the carboxylic acid component.

[0020] Examples of carboxylic acid components other than the aliphatic dicarboxylic acid compound having 6 to 10 carbon atoms include aliphatic dicarboxylic acid compounds having 5 or less or 11 or more carbon atoms, aromatic dicarboxylic acid compounds, and carboxylic acid compounds having trivalent or higher valency.

[0021] The alcohol component may appropriately contain a monohydric alcohol, and the carboxylic acid component may appropriately contain a monohydric carboxylic acid compound.

[0022] The equivalent ratio (COOH group / OH group) of the carboxy group of the carboxylic acid component to the hydroxy group of the alcohol component is preferably 0.8 or more, more preferably 0.9 or more, from the viewpoint of durability, and preferably 1.2 or less, more preferably 1.1 or less, from the viewpoint of low-temperature fixability.

[0023] The crystalline polyester resin C can be produced, for example, by polycondensing an alcohol component and a carboxylic acid component in an inert gas atmosphere, preferably in the presence of an esterification catalyst, and further, if necessary, in the presence of an esterification co-catalyst, a polymerization inhibitor, etc., preferably at a temperature of 120°C or higher and 230°C or lower.

[0024] Examples of the esterification catalyst include tin compounds such as dibutyltin oxide and tin(II) 2-ethylhexanoate, and titanium compounds such as titanium diisopropylate bistriethanolamineate. The amount of the esterification catalyst used is preferably 0.01 part by mass or more, more preferably 0.1 part by mass or more, and preferably 1.5 parts by mass or less, more preferably 1 part by mass or less, based on 100 parts by mass of the total amount of the alcohol component and the carboxylic acid component. Examples of the esterification cocatalyst include gallic acid. The amount of the esterification cocatalyst used is preferably 0.001 part by mass or more, more preferably 0.01 part by mass or more, and preferably 0.5 part by mass or less, more preferably 0.1 part by mass or less, based on 100 parts by mass of the total amount of the alcohol component and the carboxylic acid component. Examples of the polymerization inhibitor include t-butylcatechol. The amount of the polymerization inhibitor used is preferably 0.001 part by mass or more, more preferably 0.01 part by mass or more, and preferably 0.5 part by mass or less, more preferably 0.1 part by mass or less, based on 100 parts by mass of the total amount of the alcohol component and the carboxylic acid component.

[0025] In the present invention, the polyester resin may be a polyester resin modified to such an extent that its properties are not substantially impaired. Examples of the modified polyester resin include polyester resins grafted or blocked with phenol, urethane, epoxy, etc. by the methods described in JP-A-11-133668, JP-A-10-239903, JP-A-8-20636, etc. Among the modified polyester resins, a urethane-modified polyester resin obtained by extending a polyester resin with a polyisocyanate compound is preferred.

[0026] From the viewpoint of durability, the softening point of the crystalline polyester resin C is preferably 50°C or higher, more preferably 55°C or higher, still more preferably 60°C or higher, and from the viewpoint of low-temperature fixability, it is preferably 120°C or lower, more preferably 110°C or lower.

[0027] The melting point of the crystalline polyester resin C 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.

[0028] The acid value of the crystalline polyester resin C is preferably 1 mgKOH / g or higher, more preferably 3 mgKOH / g or higher, from the viewpoint of low-temperature fixability, and is preferably 20 mgKOH / g or lower, more preferably 15 mgKOH / g or lower, from the viewpoint of durability.

[0029] The content of the crystalline polyester resin C is preferably 1% by mass or higher, more preferably 3% by mass or higher, still more preferably 4% by mass or higher, from the viewpoint of low-temperature fixability, and is preferably 45% by mass or lower, more preferably 40% by mass or lower, still more preferably 30% by mass or lower, still more preferably 20% by mass or lower, from the viewpoint of durability, in the total amount of the crystalline polyester resin C and the amorphous resin A.

[0030] Examples of the amorphous resin A include amorphous polyester resins, composite resins in which a polyester resin and a styrene-based resin are bonded, polyamide resins, vinyl-based resins, epoxy resins, polycarbonate resins, polyurethane resins, etc. In the present invention, from the viewpoint of improving durability, an amorphous polyester resin or a composite resin is preferable, and an amorphous polyester resin is more preferable.

[0031] As the amorphous polyester resin, a polycondensate of an alcohol component containing an alkylene oxide adduct of bisphenol A and a carboxylic acid component is preferable.

[0032] Examples of the alkylene oxide adduct of bisphenol A include the formula (I):

[0033]

Chemical formula

[0034] (In the formula, OR and RO are oxyalkylene groups, R is an ethylene group and / or a propylene group, x and y represent the average number of moles of alkylene oxide added, and are positive numbers respectively. The value of 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.) The compound represented by is preferred.

[0035] From the viewpoint of low-temperature fixing property, the content of the alkylene oxide adduct of bisphenol A is preferably 70 mol% or more, more preferably 80 mol% or more, still more preferably 90 mol% or more, still more preferably 95 mol% or more, and even more preferably 100 mol% in the alcohol component.

[0036] Examples of other alcohol components include aliphatic diols, bisphenol A, hydrogenated bisphenol A, sorbitol, pentaerythritol, glycerin, and polyhydric alcohols such as trimethylolpropane having 3 or more valences.

[0037] Examples of the carboxylic acid component include aliphatic dicarboxylic acid compounds, aromatic dicarboxylic acid compounds, and polycarboxylic acid compounds having 3 or more valences.

[0038] Examples of the aliphatic dicarboxylic acid compound include fumaric acid, maleic acid, succinic acid, succinic acid derivatives substituted with hydrocarbon groups, glutaric acid, adipic acid, sebacic acid, anhydrides of these acids, and alkyl esters of these acids having 1 to 3 carbon atoms.

[0039] Examples of the aromatic dicarboxylic acid compound include phthalic acid, isophthalic acid, terephthalic acid, anhydrides of these acids, and alkyl esters of these acids having 1 to 3 carbon atoms.

[0040] Examples of the polycarboxylic acid compound having 3 or more valences include trimellitic acid, pyromellitic acid, anhydrides of these acids, and alkyl esters of these acids having 1 to 3 carbon atoms.

[0041] In the present invention, from the viewpoint of durability, the carboxylic acid component of the amorphous polyester resin preferably contains a succinic acid derivative substituted with a hydrocarbon group.

[0042] The hydrocarbon group in the succinic acid derivative substituted with a hydrocarbon group is preferably an alkyl group or an alkenyl group. Therefore, specific examples of the succinic acid derivative substituted with a hydrocarbon group include dodecyl succinic acid, dodecenyl succinic acid, tetrapropenyl succinic acid, decenyl succinic acid, their acid anhydrides, and their alkyl esters having 1 to 3 carbon atoms. Among these, from the viewpoint of low-temperature fixability, dodecenyl succinic acid, tetrapropenyl succinic acid, or their acid anhydrides are preferred, and dodecenyl succinic anhydride is more preferred.

[0043] From the viewpoint of hydrophobicity, the number of carbon atoms of the hydrocarbon group in the succinic acid derivative is preferably 8 or more, more preferably 10 or more, still more preferably 12 or more, and preferably 20 or less, more preferably 18 or less, still more preferably 16 or less.

[0044] From the viewpoint of hydrophobicity, the succinic acid derivative preferably contains at least one or two or more selected from the group consisting of succinic acid substituted with an alkyl group having 10 to 18 carbon atoms and succinic acid substituted with an alkenyl group having 10 to 18 carbon atoms, and more preferably contains at least one or two or more selected from the group consisting of succinic acid substituted with an alkyl group having 12 to 16 carbon atoms and succinic acid substituted with an alkenyl group having 12 to 16 carbon atoms.

[0045] From the viewpoint of hydrophobicity, the content of the succinic acid derivative is preferably 1 mol% or more, more preferably 5 mol% or more, still more preferably 7 mol% or more in the carboxylic acid component, and from the viewpoint of durability, it is preferably 40 mol% or less, more preferably 35 mol% or less, still more preferably 20 mol% or less, and even more preferably 15 mol% or less.

[0046] In addition, the alcohol component may appropriately contain a monohydric alcohol, and the carboxylic acid component may appropriately contain a monohydric carboxylic acid compound.

[0047] The equivalent ratio (COOH group / OH group) of the carboxy group of the carboxylic acid component to the hydroxyl group of the alcohol component is preferably 0.6 or more, more preferably 0.7 or more, still more preferably 0.75 or more, and preferably 1.2 or less, more preferably 1.15 or less, from the viewpoint of adjusting the softening point of the polyester resin.

[0048] The polycondensation reaction conditions of the alcohol component and the carboxylic acid component of the amorphous polyester resin are the same as those of the crystalline polyester resin, except that the suitable reaction temperature is preferably 130°C or more, more preferably 170°C or more, and preferably 250°C or less, more preferably 240°C or less.

[0049] In the composite resin containing the polyester resin and the styrene resin, the polyester resin is the same as the amorphous polyester resin, and the styrene resin is an addition polymer of a raw material monomer containing at least styrene or a styrene derivative such as α-methylstyrene or vinyltoluene (hereinafter, styrene and styrene derivatives are collectively referred to as "styrene compounds").

[0050] The content of the styrene compound, preferably styrene, in the raw material monomer of the styrene resin is preferably 50% by mass or more, more preferably 70% by mass or more, still more preferably 80% by mass or more, from the viewpoint of durability, and preferably 95% by mass or less, more preferably 93% by mass or less, still more preferably 90% by mass or less, from the viewpoint of low-temperature fixability.

[0051] In addition, the styrene resin may contain a (meth)acrylic acid alkyl ester having 7 or more carbon atoms in the alkyl group as a raw material monomer. Examples of the (meth)acrylic acid alkyl ester include 2-ethylhexyl (meth)acrylate, (iso)octyl (meth)acrylate, (iso)decyl (meth)acrylate, (iso)stearyl (meth)acrylate, and the like. It is preferable to use one or more of these. In this specification, "(iso)" means including both the case where this group exists and the case where it does not exist, and when these groups do not exist, it indicates normal. Also, "(meth)acrylic acid" indicates acrylic acid, methacrylic acid, or both of them.

[0052] The carbon number of the alkyl group in the (meth)acrylic acid alkyl ester as a raw material monomer of the styrene 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 fixability of the toner. The carbon number of the alkyl ester refers to the carbon number derived from the alcohol component constituting the ester.

[0053] The raw material monomers of the styrene resin 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; N-vinyl compounds such as N-vinylpyrrolidone, and the like.

[0054] The addition polymerization reaction of the raw material monomers of the styrene resin can be carried out by a conventional method in the presence of a polymerization initiator such as dibutyl peroxide, dicumyl peroxide, a polymerization inhibitor, a crosslinking agent, etc., in the presence of an organic solvent or without a solvent. As the temperature condition, it is preferably 110 °C or higher, more preferably 140 °C or higher, and preferably 200 °C or lower, more preferably 170 °C or lower.

[0055] When using an organic solvent during 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 with respect to 100 parts by mass of the raw material monomers of the styrene resin.

[0056] The composite resin is preferably a resin in which a polyester resin and a styrene resin are bonded, and more preferably a resin chemically bonded through a bifunctional monomer capable of reacting with both the raw material monomers of the polyester resin and the raw material monomers of the styrene resin.

[0057] The bifunctional monomer preferably has at least one functional group selected from the group consisting of a hydroxyl group, a carboxyl group, an epoxy group, a primary amino group, and a secondary amino group in the molecule, preferably a hydroxyl group and / or a carboxyl group, more preferably a carboxyl group, and an ethylenically unsaturated bond. A compound having at least one selected from the group consisting of acrylic acid, methacrylic acid, fumaric acid, maleic acid, and maleic anhydride is more preferable, and at least one selected from the group consisting of acrylic acid, methacrylic acid, and fumaric acid is even more preferable from the viewpoint of the reactivity of the polycondensation reaction and the addition polymerization reaction. However, when used together with a polymerization inhibitor, a polycarboxylic acid-based compound having an ethylenically unsaturated bond such as fumaric acid functions as a raw material monomer of the polyester resin. In this case, fumaric acid, etc. is not a bifunctional monomer but a raw material monomer of the polyester resin.

[0058] The amount of the bifunctional monomer used is preferably 1 mol or more, more preferably 2 mol or more, per 100 mol of the total alcohol components of the polyester resin, from the viewpoint of low-temperature fixability, and preferably 30 mol or less, more preferably 20 mol or less, still more preferably 10 mol or less, from the viewpoint of enhancing the dispersibility between the styrene resin and the polyester resin and improving the durability of the toner. Also, the amount of the bifunctional monomer used is preferably 1 part by mass or more, more preferably 2 parts by mass or more, per 100 parts by mass of the total raw material monomers of the styrene resin, from the viewpoint of low-temperature fixability, and preferably 30 parts by mass or less, more preferably 20 parts by mass or less, still more preferably 10 parts by mass or less, from the viewpoint of enhancing the dispersibility between the styrene resin and the polyester resin and improving the durability of the toner. Here, the polymerization initiator is included in the total of the raw material monomers of the styrene resin.

[0059] Specifically, the composite resin is preferably produced by the following method. When using the bifunctional monomer, the bifunctional monomer is preferably used in an addition polymerization reaction together with the raw material monomers of the styrene resin, from the viewpoint of improving the durability and low-temperature fixability of the toner.

[0060] (i) A method in which after the step (A) of polycondensation reaction with the raw material monomers of the polyester resin, the step (B) of addition polymerization reaction with the raw material monomers of the styrene resin and the bifunctional monomer is carried out In this method, step (A) is carried out under reaction temperature conditions suitable for the polycondensation reaction, the reaction temperature is lowered, and step (B) is carried out under temperature conditions suitable for the addition polymerization reaction. The raw material monomers of the styrene resin and the bifunctional monomer are preferably added into the reaction system at a temperature suitable for the addition polymerization reaction. The bifunctional monomer undergoes an addition polymerization reaction and also reacts with the polyester resin. After step (B), the reaction temperature is raised again, and if necessary, a raw material monomer of a polyester resin having a trivalent or higher valence that serves as a crosslinking agent, etc. is added to the polymerization system, and the polycondensation reaction in step (A) and the reaction with the bifunctional monomer can be further advanced.

[0061] (ii) A method in which after step (B) of the addition polymerization reaction using the raw material monomers of the styrene resin and the bifunctional monomer, step (A) of the polycondensation reaction using the raw material monomers of the polyester resin is carried out In this method, step (B) is carried out under reaction temperature conditions suitable for the addition polymerization reaction, the reaction temperature is raised, and the polycondensation reaction of step (A) is carried out under temperature conditions suitable for the polycondensation reaction. The bifunctional monomer is involved in both the addition polymerization reaction and the polycondensation 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 adjusted by adding an esterification catalyst at a temperature suitable for the polycondensation reaction.

[0062] (iii) A method in which step (A) of the polycondensation reaction using the raw material monomers of the polyester resin and step (B) of the addition polymerization reaction using the raw material monomers of the styrene resin and the bifunctional monomer are carried out under conditions where they proceed in parallel In this method, step (A) and step (B) are carried out in parallel under reaction temperature conditions suitable for the addition polymerization reaction, the reaction temperature is raised, and under temperature conditions suitable for the polycondensation reaction, a raw material monomer of a polyester resin having a valency of 3 or more that serves as a crosslinking agent is added to the polymerization system as needed, and the polycondensation reaction of step (A) is further carried out. Preferably, at that time, under temperature conditions suitable for the polycondensation reaction, a polymerization inhibitor can be added to proceed only with the polycondensation reaction. The bifunctional monomer is involved in both the addition polymerization reaction and the polycondensation reaction.

[0063] In the method of (i) above, instead of step (A) of carrying out the polycondensation reaction, a pre-polymerized polycondensation resin may be used. In the method of (iii) above, when carrying out the reaction under conditions where step (A) and step (B) proceed in parallel, a mixture containing the raw material monomers of the styrene resin can be dropped into a mixture containing the raw material monomers of the polyester resin and reacted.

[0064] The methods of (i) to (iii) above are preferably carried out in the same container.

[0065] The mass ratio of the polyester resin to the styrene resin in the composite resin (polyester resin / styrene resin) is preferably 98 / 2 or less, more preferably 95 / 5 or less, still more preferably 90 / 10 or less from the viewpoint of smear property, and is preferably 60 / 40 or more, more preferably 70 / 30 or more, still more preferably 75 / 25 or more from the viewpoint of low-temperature fixing property. In the above calculation, the mass of the polyester resin is the amount obtained by excluding the amount of reaction water (calculated value) dehydrated by the polycondensation reaction from the mass of the raw material monomers of the polyester resin used, and the amounts of both reactive monomers are included in the amount of the raw material monomers of the polyester resin. The amount of the styrene resin is the total amount of the raw material monomers of the styrene resin and the polymerization initiator.

[0066] The softening point of the amorphous resin A is preferably 90°C or higher, more preferably 100°C or higher from the viewpoint of durability, and is preferably 150°C or lower, more preferably 140°C or lower from the viewpoint of low-temperature fixing property.

[0067] Note that the amorphous resin A may be composed of resins having different softening points from the viewpoints of low-temperature fixing property and fixing width. The difference in the softening points of the two resins is preferably 10°C or higher, more preferably 12°C or higher, and is preferably 60°C or lower, more preferably 30°C or lower, still more preferably 20°C or lower.

[0068] The softening point of the amorphous resin with a higher softening point (resin AH) is preferably 100°C or higher, more preferably 110°C or higher, still more preferably 120°C or higher from the viewpoint of fixing width, and is preferably 180°C or lower, more preferably 160°C or lower, still more preferably 140°C or lower from the viewpoint of low-temperature fixing property.

[0069] Also, the softening point of the amorphous resin with a lower softening point (resin AL) is preferably 70°C or higher, more preferably 90°C or higher, still more preferably 100°C or higher from the viewpoint of durability, and is preferably 130°C or lower, more preferably 125°C or lower, still more preferably 120°C or lower from the viewpoint of low-temperature fixing property.

[0070] The mass ratio of resin AH to resin AL (resin AH / resin AL) is preferably 10 / 90 or more, more preferably 20 / 80 or more, still more preferably 30 / 70 or more, and is preferably 90 / 10 or less, more preferably 80 / 20 or less, still more preferably 70 / 30 or less.

[0071] From the viewpoint of durability, the glass transition temperature of the amorphous resin A is preferably 40°C or higher, more preferably 50°C or higher, and from the viewpoint of low-temperature fixability, it is preferably 80°C or lower, more preferably 70°C or lower, still more preferably 65°C or lower.

[0072] From the viewpoint of low-temperature fixability, the acid value of the amorphous resin A is preferably 1 mgKOH / g or higher, more preferably 3 mgKOH / g or higher, and from the viewpoint of durability, it is preferably 20 mgKOH / g or lower, more preferably 15 mgKOH / g or lower.

[0073] From the viewpoint of durability, the number-average molecular weight of the amorphous resin A is preferably 1,000 or higher, more preferably 1,500 or higher, still more preferably 2,000 or higher, and from the viewpoint of low-temperature fixability, it is preferably 6,000 or lower, more preferably 5,000 or lower, still more preferably 4,000 or lower.

[0074] From the viewpoint of durability, the weight-average molecular weight of the amorphous resin A is preferably 5,000 or higher, more preferably 6,000 or higher, still more preferably 8,000 or higher, and from the viewpoint of low-temperature fixability, it is preferably 500,000 or lower, more preferably 200,000 or lower, still more preferably 150,000 or lower.

[0075] The mass ratio of the crystalline polyester resin C to the amorphous resin A (crystalline polyester resin C / amorphous resin A) is preferably 1 / 99 or more, more preferably 3 / 97 or more, still more preferably 5 / 95 or more, from the viewpoint of low-temperature fixability, and preferably 40 / 60 or less, more preferably 35 / 65 or less, still more preferably 30 / 70 or less, from the viewpoint of durability.

[0076] In the toner, the crystalline polyester resin C and the amorphous resin A are contained as a binder resin.

[0077] Examples of other binder resins include vinyl resins such as styrene-acrylic resins, epoxy resins, polycarbonates, polyurethanes, and composite resins containing two or more of these resins.

[0078] The total content of the crystalline polyester resin C and the amorphous resin A is preferably 70% by mass or more, more preferably 80% by mass or more, still more preferably 90% by mass or more, still more preferably 95% by mass or more, still more preferably 100% by mass in the binder resin.

[0079] Also, the content of the binder resin is preferably 60% by mass or more, more preferably 70% by mass or more, still more preferably 80% by mass or more in the toner, and preferably less than 100% by mass, more preferably 98% by mass or less, still more preferably 95% by mass or less.

[0080] Examples of the release agent include hydrocarbon waxes such as polypropylene wax, polyethylene wax, polypropylene polyethylene copolymer wax, microcrystalline wax, paraffin wax, Fischer-Tropsch wax and their oxides; ester waxes such as carnauba wax, montan wax and their deacidified waxes, fatty acid ester waxes; fatty acid amides, fatty acids, higher alcohols, fatty acid metal salts, etc. These can be used alone or in combination of two or more.

[0081] From the perspective of durability, the melting point of the release agent is preferably 60°C or higher, more preferably 70°C or higher, and from the perspective of low-temperature fixability, it is preferably 160°C or lower, more preferably 140°C or lower, still more preferably 120°C or lower, and even more preferably 110°C or lower.

[0082] From the perspectives of the low-temperature fixability and durability of the toner and the dispersibility in the binder resin, the content of the release agent is preferably 0.5 part by mass or more, more preferably 1 part by mass or more, still more preferably 1.5 parts by mass or more, per 100 parts by mass of the binder resin, and is preferably 10 parts by mass or less, more preferably 8 parts by mass or less, still more preferably 7 parts by mass or less.

[0083] In addition to the binder resin and the release agent, the toner may contain additives such as a colorant, a charge control agent, magnetic powder, a fluidity improver, a conductivity adjuster, a reinforcing filler such as a fibrous substance, an antioxidant, and a cleaning property improver.

[0084] As the colorant, dyes, pigments, magnetic materials, etc. used as colorants for toner can be used. For example, 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. may be mentioned. In the present invention, the toner may be either a black toner or a color toner.

[0085] From the perspective 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, per 100 parts by mass of the binder resin, and is preferably 40 parts by mass or less, more preferably 20 parts by mass or less, still more preferably 10 parts by mass or less.

[0086] The charge control agent is not particularly limited, and may contain either a positive charge control agent or a negative charge control agent.

[0087] Examples of positive 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", "Bontron N-11" (manufactured by Orient Chemical Industries, Ltd.), etc.; triphenylmethane dyes containing a tertiary amine as a side chain; quaternary ammonium salt compounds such as "Bontron P-51" (manufactured by Orient Chemical Industries, Ltd.), cetyltrimethylammonium bromide, "COPY CHARGE PX VP435" (manufactured by Clariant), etc.; polyamine resins such as "AFP-B" (manufactured by Orient Chemical Industries, Ltd.), etc.; imidazole derivatives such as "PLZ-2001", "PLZ-8001" (manufactured by Shikoku Kasei Kogyo Co., Ltd.), etc.; styrene-acrylic resins such as "FCA-701PT", "FCA-201-PS" (manufactured by Fujikura Kasei Co., Ltd.), etc.

[0088] Examples of negative charge control agents include metal-containing azo dyes such as "Vari Fast Black 3804", "Bontron S-31", "Bontron S-32", "Bontron S-34", "Bontron S-36" (manufactured by Orient Chemical Industries, Ltd.), "Eisenspirone Black TRH", "T-77" (manufactured by Hodogaya Chemical Co., Ltd.), etc.; metal compounds of benzoic acid compounds such as "LR-147", "LR-297" (manufactured by Nippon Carlit Co., Ltd.), etc.; metal compounds of salicylic acid compounds such as "Bontron E-81", "Bontron E-84", "Bontron E-88", "Bontron E-304" (manufactured by Orient Chemical Industries, Ltd.), "TN-105" (manufactured by Hodogaya Chemical Co., Ltd.), etc.; copper phthalocyanine dyes; quaternary ammonium salts such as "COPY CHARGE NX VP434" (manufactured by Clariant), nitroimidazole derivatives, etc.; organometallic compounds, etc.

[0089] From the perspective of the charging stability of the toner, the content of the charge control agent is preferably 0.01 part by mass or more, more preferably 0.2 part by mass or more, and preferably 10 parts by mass or less, more preferably 5 parts by mass or less, still more preferably 3 parts by mass or less, and still more preferably 2 parts by mass or less, based on 100 parts by mass of the binder resin.

[0090] In the present invention, a mixture containing a crystalline polyester resin C, an amorphous resin A, a release agent, and further, if necessary, additives such as a colorant and a charge control agent is subjected to a step of melt-kneading using an open-roll type twin-screw kneader.

[0091] The mixture to be subjected to melt-kneading may be kneaded at once or divided and kneaded, but it is preferable to mix it in advance with a mixer such as a Henschel mixer or a ball mill and then supply it to an open-roll type twin-screw kneader.

[0092] The open-roll type twin-screw kneader has two rolls and the melt-kneading part is not sealed but open, and can easily dissipate the kneading heat generated during melt-kneading. The open-roll type twin-screw kneader used in the present invention is provided with a plurality of raw material supply ports and a kneaded product discharge port provided along the axial direction of the rolls, and from the perspective of production efficiency, it is preferably a continuous open-roll type twin-screw kneader.

[0093] The open-roll type twin-screw kneader used in the present invention is a kneader equipped with two rolls having different peripheral speeds, that is, a high-speed rotation roll with a high peripheral speed and a low-speed rotation roll with a low peripheral speed. In the present invention, from the perspective of improving the dispersibility of the crystalline polyester resin, it is preferable that the high-speed rotation roll is a heating roll and the low-speed rotation roll is a cooling roll.

[0094] The temperature of the roll can be adjusted, for example, by the temperature of the heat medium passed through the inside of the roll, and each roll may be divided into two or more parts inside the roll and passed through heat media with different temperatures.

[0095] The temperature on the discharge side of the highly rotating roll is -20°C or higher, preferably -15°C or higher, more preferably -10°C or higher, still more preferably -5°C or higher, and still more preferably at or above the melting point of the crystalline polyester resin C, from the viewpoint of improving the dispersibility of the crystalline polyester resin, and is +15°C or lower, preferably +13°C or lower, more preferably +12°C or lower, of the melting point of the crystalline polyester resin C.

[0096] On the other hand, the temperature on the raw material input side of the highly rotating roll is preferably +5°C or higher, more preferably +15°C or higher, still more preferably +25°C or higher, and still more preferably +40°C or higher, and is preferably +65°C or lower, more preferably +60°C or lower, still more preferably +55°C or lower, of the melting point of the crystalline polyester resin C, from the viewpoint of melting the crystalline polyester resin.

[0097] The temperature on the discharge side of the low rotating roll is preferably 25°C or higher, more preferably 30°C or higher, and is preferably 80°C or lower, more preferably 50°C or lower, from the viewpoint of improving the dispersibility of the crystalline polyester resin.

[0098] The temperature on the raw material input side of the low rotating roll is preferably 25°C or higher, more preferably 40°C or higher, and is preferably 80°C or lower, more preferably 70°C or lower, from the viewpoint of reducing the mechanical force during melt-kneading and suppressing heat generation.

[0099] Both the high-speed roll and the low-speed roll preferably have a higher temperature on the raw material input side than on the kneaded product discharge side. The temperature difference between the raw material input side and the kneaded product discharge side of the high-speed roll is preferably 5°C or more, more preferably 20°C or more, still more preferably 25°C or more, and preferably 60°C or less, more preferably 55°C or less, from the viewpoints of preventing the kneaded product from detaching from the roll, reducing the mechanical force during melt-kneading, and suppressing heat generation. The temperature difference between the raw material input side and the kneaded product discharge side of the low-speed roll is preferably 5°C or more and preferably 50°C or less from the viewpoints of improving the dispersibility of the crystalline polyester resin, reducing the mechanical force during melt-kneading, and suppressing heat generation.

[0100] The temperature of the raw material input side of the high-speed roll and the low-speed roll refers to the set temperature at the end of the raw material input side, and the temperature of the kneaded product discharge side refers to the set temperature at the end of the kneaded product discharge side, respectively.

[0101] The peripheral speed of the high-speed roll is preferably 2 m / min or more, more preferably 10 m / min or more, still more preferably 25 m / min or more, and preferably 100 m / min or less, more preferably 75 m / min or less, still more preferably 50 m / min or less, from the viewpoints of improving the dispersibility of the crystalline polyester resin, reducing the mechanical force during melt-kneading, and suppressing heat generation. The peripheral speed of the low-speed roll is preferably 1 m / min or more, more preferably 5 m / min or more, still more preferably 15 m / min or more, and preferably 90 m / min or less, more preferably 60 m / min or less, still more preferably 30 m / min or less, from the same viewpoints. Also, the ratio of the peripheral speeds of the two rolls (low-speed roll / high-speed roll) is preferably 1 / 10 or more, more preferably 3 / 10 or more, and preferably 9.9 / 10 or less, more preferably 8 / 10 or less.

[0102] In addition, there are no particular limitations on the structure, size, material, etc. of each roll. The roll surface has grooves used for kneading, and examples of this shape include linear, spiral, wavy, concave-convex, etc.

[0103] After melt-kneading, it is preferable to appropriately cool the kneaded product until it reaches a hardness that can be pulverized, and, if necessary, perform a pulverization step and a classification step to obtain toner particles. Here, cooling means cooling the kneaded product to 0°C or higher and 50°C or lower, or cooling it to a temperature equal to or lower than the glass transition temperature of the binder resin in the kneaded product.

[0104] In the pulverization of the kneaded product, the kneaded product may be pulverized at once to a desired particle size or may be pulverized stepwise, but from the viewpoint of efficient and more uniform pulverization, it is preferable to perform the pulverization in two steps: coarse pulverization and fine pulverization.

[0105] Examples of the pulverizer used for coarse pulverization include a hammer mill, a cutter mill, an atomizer, a rotorplex, and the like.

[0106] In coarse pulverization, it is preferable to pulverize until the maximum diameter becomes 3 mm or less. For example, a pulverized product with a maximum diameter of 3 mm or less can be obtained by appropriately coarsely pulverizing the kneaded product until the particle size becomes about 0.05 mm or more and 3 mm or less, and then passing it through a sieve with a mesh size of 3 mm.

[0107] Examples of the pulverizer used for fine pulverization include jet mills such as a fluidized bed jet mill and an impact plate jet mill, and mechanical mills.

[0108] The degree of fine pulverization is preferably adjusted as appropriate according to the particle size of the target toner particles.

[0109] Examples of the classifier used for classification include an air classifier, an inertial classifier, a sieve classifier, and the like. During the classification step, the pulverized product that was not sufficiently pulverized and removed may be returned to the pulverization step, and if necessary, the pulverization step and the classification step may be repeated.

[0110] In the present invention, it is preferable that the obtained toner particles further have an external addition step of mixing with an external additive.

[0111] Examples of the external additive include inorganic fine particles such as silica, alumina, titania, zirconia, tin oxide, and zinc oxide, and organic fine particles such as melamine resin fine particles and polytetrafluoroethylene resin fine particles. Two or more of these may be used in combination. Among these, silica is preferable, and from the viewpoint of the durability of the toner, hydrophobic silica that has been hydrophobically treated is more preferable.

[0112] Examples of the hydrophobizing agent for hydrophobizing the surface of the silica particles include hexamethyldisilazane (HMDS), dimethyldichlorosilane (DMDS), cyclic silazane, silicone oil, aminosilane, octyltriethoxysilane (OTES), and methyltriethoxysilane.

[0113] From the viewpoints of the chargeability and fluidity of the toner, the average particle diameter of the external additive is preferably 5 nm or more, more preferably 10 nm or more, still more preferably 15 nm or more, and preferably 250 nm or less, more preferably 200 nm or less, still more preferably 90 nm or less.

[0114] From the viewpoints of the chargeability and fluidity of the toner, the content of the external additive is preferably 0.05 part by mass or more, more preferably 0.1 part by mass or more, still more preferably 0.3 part by mass or more, with respect to 100 parts by mass of the toner particles before being treated with the external additive, and preferably 5 parts by mass or less, more preferably 3 parts by mass or less.

[0115] The volume median diameter (D 50 ) of the toner obtained by the method 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 diameter (D 50 ) means the particle diameter at which the cumulative volume frequency calculated by the volume fraction becomes 50% when calculated from the smaller particle diameter. Further, when the toner is treated with an external additive, the volume median diameter of the toner particles before being treated with the external additive is defined as the volume median diameter of the toner.

[0116] The toner obtained by the method of the present invention can be used as a one-component developer toner as it is, or as a two-component developer toner mixed with a carrier, in an image forming apparatus using a one-component development system or a two-component development system, respectively.

Examples

[0117] Hereinafter, the present invention will be specifically described by way of examples. However, the present invention is not limited to these examples. Physical properties such as those of resins can be measured by the following methods.

[0118] 〔Softening point of resin〕 Using a flow tester "CFT-500D" (manufactured by Shimadzu Corporation), while heating 1 g of a sample at a heating rate of 6 °C / min, a load of 1.96 MPa is applied by a plunger and extruded from a nozzle with a diameter of 1 mm and a length of 1 mm. The plunger descent amount 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.

[0119] 〔Maximum peak temperature of endotherm of resin〕 Using a differential scanning calorimeter "Q-100" (manufactured by TA Instruments Japan Co., Ltd.), 0.01 to 0.02 g of a sample is weighed into an aluminum pan, cooled from room temperature (25 °C) to 0 °C at a cooling rate of 10 °C / min, and maintained at 0 °C for 1 minute. Then, it is measured at a heating rate of 10 °C / min. Among the observed endothermic peaks, the temperature of the peak with the largest peak area is taken as the maximum peak temperature of endotherm.

[0120] 〔Glass transition temperature of amorphous resin〕 Using a differential scanning calorimeter "Q-100" (manufactured by TA Instruments Japan), 0.01 to 0.02 g of a sample is weighed into an aluminum pan, heated to 200 °C, and cooled from that temperature to 0 °C at a cooling rate of 10 °C / min. Next, the sample is heated at a heating rate of 10 °C / min, and the endothermic peak is measured. The temperature of the intersection of the extension line of the baseline below the maximum peak temperature of endotherm and the tangent line showing the maximum slope from the rising part of the peak to the peak apex is taken as the glass transition temperature.

[0121] 〔Acid value of resin〕 It is measured based on the method of JIS K 0070:1992. However, for the measurement solvent only, from the mixed solvent of ethanol and ether specified in JIS K 0070, the amorphous resin is changed to a mixed solvent of acetone and toluene (acetone:toluene = 1:1 (volume ratio)), and the crystalline resin is changed to a mixed solvent of chloroform and dimethylformamide (chloroform:dimethylformamide = 7:3 (volume ratio)).

[0122] 〔Number average molecular weight and weight average molecular weight of resin〕 The number average molecular weight and weight average molecular weight are determined by gel permeation chromatography (GPC) method according to the following method. (1) Preparation of sample solution The resin was dissolved in tetrahydrofuran so that the concentration became 0.5 g / 100 mL. Then, this solution was filtered using a fluororesin filter with a pore size of 2 μm (manufactured by Sumitomo Electric Industries, Ltd., trade name: FP-200) to remove insoluble components, and used as a sample solution. (2) Molecular weight measurement Using the following measuring device and analytical column, tetrahydrofuran was used as the eluent and flowed at a flow rate of 1 mL per minute, and the column was stabilized in a constant temperature bath at 40°C. 100 μL of the sample solution was injected there for measurement. The molecular weight of the sample was calculated based on a calibration curve prepared in advance. For the calibration curve at this time, several monodisperse polystyrenes with known molecular weights (manufactured by Tosoh Corporation; 2.63×10 3 , 2.06×10 4 , 1.02×10 5 , manufactured by GL Sciences Inc.; 2.10×10 3 , 7.00×10 3 , 5.04×10 4 ) were used as standard samples. Measuring device: CO-8010 (trade name, manufactured by Tosoh Corporation) Analytical column: GMH XL +G3000H XL (Both are trade names, manufactured by Tosoh Corporation)

[0123] 〔Melting Point of Release Agent〕 Using a differential scanning calorimeter “Q-100” (manufactured by TA Instruments Japan Co., Ltd.), weigh 0.02 g of the sample into an aluminum pan, heat it up to 200 °C, and then cool it from 200 °C to 0 °C at a cooling rate of 10 °C / min. Next, heat the sample at a heating rate of 10 °C / min, measure the heat quantity, and take the maximum peak temperature of endotherm as the melting point.

[0124] 〔Average Particle Diameter of Externally Added Agent〕 The average particle diameter refers to the number average particle diameter. Measure the particle diameters (average value of major axis and minor axis) of 500 particles from a scanning electron microscope (SEM) photograph, and take their number average value.

[0125] 〔Volume Median Diameter (D 50 ) of Toner〕 · Measuring instrument: “Coulter Multisizer (registered trademark) III” (manufactured by Beckman Coulter, Inc.) · Aperture diameter: 50 μm · Analysis software: “Multisizer (registered trademark) III Version 3.51” (manufactured by Beckman Coulter, Inc.) · Electrolyte: “Isoton (registered trademark) II” (manufactured by Beckman Coulter, Inc.) · Dispersion liquid: A solution prepared by dissolving polyoxyethylene lauryl ether “Emulgen (registered trademark) 109P” [manufactured by Kao Corporation, HLB (Griffin) = 13.6] in the electrolyte to adjust to 5% by mass. · Dispersion conditions: Add 10 mg of the measurement sample to 5 mL of the above dispersion liquid, disperse it with an ultrasonic disperser (machine name: US-1 manufactured by SND Co., Ltd., output: 80 W) for 1 minute, then add 25 mL of the electrolyte, and further disperse it with the ultrasonic disperser for 1 minute to prepare a sample dispersion liquid. · Measurement conditions: After adjusting the concentration so that the particle diameters of 30,000 particles can be measured in 20 seconds by adding the above sample dispersion liquid to 100 mL of the electrolyte, measure 30,000 particles, and obtain the volume median diameter (D 50 ) from the particle size distribution.

[0126] Production Example 1 of Alkenyl Succinic Anhydride (1) Propylene tetramer (manufactured by Nippon Oil Corporation, trade name: "Light Tetramer") was fractionated under heating conditions of 183 to 208 °C to obtain an alkylene compound (a). The obtained alkylene compound (a) had 40 peaks in gas chromatography-mass spectrometry described below. The distribution of the alkylene compound was measured according to the analysis by gas chromatography-mass spectrometry of alkylene compound A in JP-A-2014-013384, and C 9 H 18 : 0.5 mass%, C 10 H 20 : 4 mass%, C 11 H 22 : 20 mass%, C 12 H 24 : 66 mass%, C 13 H 26 : 9 mass%, C 14 H 28 : 0.5 mass% (the number of peaks corresponding to alkylene compounds having 9 to 14 carbon atoms was 6).

[0127] (2) 542.4 g of alkylene compound (a), 157.2 g of maleic anhydride, 0.4 g of antioxidant "Chelex-O" (manufactured by SC Organic Chemicals Co., Ltd., Triisooctyl phosphite), and 0.1 g of butylhydroquinone as a polymerization inhibitor were charged into a 1 L autoclave manufactured by Nitto Koatsu Co., Ltd., and pressurized nitrogen substitution (0.2 MPaG) was repeated three times. After starting stirring at 60 °C, the temperature was raised to 230 °C over 1 hour and reacted for 6 hours. The pressure at the time of reaching the reaction temperature was 0.3 MPaG. After completion of the reaction, it was cooled to 80 °C, returned to normal pressure (101.3 kPa), and transferred to a four-necked flask with a volume of 1 liter. The temperature was raised to 180 °C with stirring, and the remaining alkylene compound was distilled off at 1.3 kPa in 1 hour. Subsequently, after cooling to room temperature (25 °C) and returning to normal pressure (101.3 kPa), 406.1 g of the target alkenyl succinic anhydride A was obtained. The average molecular weight of alkenyl succinic anhydride A determined from the acid value was 268.

[0128] Resin Production Example 1 The alcohol component and carboxylic acid component shown in Table 1 were placed in a 5-liter four-necked flask equipped with a thermometer, a stainless steel stirring rod, a reflux condenser, and a nitrogen inlet tube, and heated in a mantle heater under a nitrogen atmosphere to 200°C over 8 hours. Thereafter, an esterification catalyst was added, and the reaction was carried out at 8.0 kPa until the softening point shown in Table 1 was reached, to obtain a crystalline polyester resin (Resins C1 to C7). The physical properties are shown in Table 1.

[0129] [Table 1]

[0130] Resin Production Example 2 The raw material monomers, esterification catalyst, and esterification co-catalyst of the polyester resin other than trimellitic anhydride shown in Table 2 were placed in a 5-liter four-necked flask equipped with a nitrogen inlet tube, a stirrer, and a thermocouple, heated to 235°C under a nitrogen atmosphere, and then polycondensed at 235°C for 6 hours. Thereafter, the temperature was lowered to 210°C, trimellitic anhydride was added, and after reacting at 210°C for 1 hour, the reaction was further carried out at 210°C under a reduced pressure of 10 kPa until the softening point described in Table 2 was reached, to obtain an amorphous polyester resin (Resin AH1). The physical properties are shown in Table 2.

[0131] Resin Production Example 3 The raw material monomers, esterification catalyst, and esterification co-catalyst of the polyester resin other than trimellitic anhydride and fumaric acid shown in Table 2 were placed in a 5-liter four-necked flask equipped with a nitrogen inlet tube, a stirrer, and a thermocouple. After heating to 235°C under a nitrogen atmosphere, polycondensation was carried out at 235°C for 6 hours. Then, the temperature was lowered to 160°C, and a mixture of both reactive monomers, the raw material monomers of the styrene resin, and a polymerization initiator was added dropwise over 1 hour using a dropping funnel. After the addition, while maintaining the temperature at 160°C, the addition polymerization reaction was aged for 1 hour, then raised to 200°C, and the pressure was reduced to 10 kPa for 1 hour. After releasing the pressure, the temperature was lowered to 180°C, trimellitic anhydride, fumaric acid, and a polymerization inhibitor shown in Table 2 were added, and after holding at 180°C for 1 hour, the temperature was raised from 180°C to 210°C at 10°C / h and reacted at 210°C for 1 hour. Further, the reaction was carried out under a reduced pressure of 10 kPa at 210°C until the softening point described in Table 2 was reached to obtain an amorphous composite resin (resin AH2). The physical properties are shown in Table 2.

[0132] Resin Production Example 4 The raw material monomers, esterification catalyst, and esterification co-catalyst of the polyester resin other than trimellitic anhydride and fumaric acid shown in Table 2 were placed in a 5-liter four-necked flask equipped with a nitrogen inlet tube, a stirrer, and a thermocouple. After heating to 235°C under a nitrogen atmosphere, polycondensation was carried out at 235°C for 6 hours. Then, the temperature was lowered to 180°C, trimellitic anhydride, fumaric acid, and a polymerization inhibitor were added, and after holding at 180°C for 1 hour, the temperature was raised from 180°C to 210°C at 10°C / h and reacted at 210°C for 1 hour. Further, the reaction was carried out under a reduced pressure of 10 kPa at 210°C until the softening point described in Table 2 was reached to obtain an amorphous polyester resin (resin AH3). The physical properties are shown in Table 2.

[0133] Resin Production Example 5 The raw material monomers, esterification catalyst, and esterification co-catalyst of the polyester resin shown in Table 2 were placed in a 5-liter four-necked flask equipped with a nitrogen inlet tube, a stirrer, and a thermocouple. After heating to 235°C under a nitrogen atmosphere, polycondensation was carried out at 235°C for 6 hours. Then, the temperature was lowered to 210°C, and the reaction was carried out under a reduced pressure of 10 kPa until the softening point shown in Table 2 was reached, to obtain an amorphous polyester resin (resins AL1 and AL3). The physical properties are shown in the table.

[0134] Resin Production Example 6 The raw material monomers, esterification catalyst, and esterification co-catalyst of the polyester resin other than fumaric acid shown in Table 2 were placed in a 5-liter four-necked flask equipped with a water removal tube equipped with a nitrogen inlet tube, a stirrer, and a thermocouple. After heating to 235°C under a nitrogen atmosphere, polycondensation was carried out at 235°C for 6 hours. Then, the temperature was lowered to 160°C, and a mixture of both reactive monomers, the raw material monomers of the styrene resin, and a polymerization initiator was added dropwise over 1 hour using a dropping funnel. After the addition, while maintaining the temperature at 160°C, the addition polymerization reaction was aged for 1 hour, then the temperature was raised to 200°C, and the pressure was reduced to 10 kPa for 1 hour. After releasing the pressure, the temperature was lowered to 180°C, fumaric acid and a polymerization inhibitor shown in Table 2 were added, and after maintaining the temperature at 180°C for 1 hour, the temperature was raised from 180°C to 210°C at 10°C / h, and the reaction was carried out at 210°C for 1 hour. Further, the reaction was carried out under a reduced pressure of 10 kPa at 210°C until the softening point shown in Table 2 was reached, to obtain an amorphous composite resin (resin AL2). The physical properties are shown in Table 2.

[0135]

Table 2

[0136] Examples 1 to 10 and Comparative Examples 1 to 5 100 parts by mass of the binder resin shown in Table 3, 5 parts by mass of the colorant "ECB-301" (manufactured by Dainichi Seika Co., Ltd., phthalocyanine blue (P.B.15:3)), 3 parts by mass of the release agent "Carnauba Wax C1" (manufactured by Kato Yoko Co., Ltd., melting point: 83°C), 3 parts by mass of the release agent "HNP-9" (manufactured by Nippon Seiro Co., Ltd., paraffin wax, melting point: 75°C), and 0.5 parts by mass of the charge control agent "Bontron E-304" (manufactured by Orient Chemical Co., Ltd.) were mixed with a Henschel mixer.

[0137] The obtained raw material mixture was supplied to a continuous open roll type twin-screw kneader "Neodeck" (manufactured by Mitsui Mining Co., Ltd.) using a table feeder for kneading to obtain a kneaded product. The continuous open roll type twin-screw kneader used at this time had a roll outer diameter of 0.14 m and an effective roll length of 0.8 m. The operating conditions were such that the rotational speed of the high-speed roll (front roll) was 75 r / min (circumferential speed 33 m / min), the rotational speed of the low-speed roll (rear roll) was 50 r / min (circumferential speed 22 m / min), and the roll gap was 0.1 mm. The temperature of the heating and cooling medium inside the roll was set to the temperatures shown in Table 3 for the raw material input side (IN) and the kneaded product discharge side (OUT) of the high-speed roll, and the temperature of the raw material input side of the low-speed roll was set to 65°C and the temperature of the kneaded product discharge side was set to 30°C. Also, the supply rate of the raw material mixture was 10 kg / h and the average residence time was about 5 minutes.

[0138] The obtained kneaded product was cooled to 25°C and roughly pulverized by a pulverizer "Rotoplex" (manufactured by Toa Machinery Co., Ltd.) to obtain a roughly pulverized product with a particle size of 2 mm or less using a sieve with an opening of 2 mm. Fine pulverization and upper limit classification (removal of coarse powder) were performed using a counter jet mill "400AFG" (manufactured by Hosokawa Alpine Co., Ltd.). Further, lower limit classification (removal of fine powder) was performed using a classifier "TTSP" (manufactured by Hosokawa Alpine Co., Ltd.) to obtain toner particles with a volume median particle size of 6.5 μm.

[0139] 100 parts by mass of the obtained toner particles, 1.0 part by mass of hydrophobic silica "R972" (manufactured by Nippon Aerosil Co., Ltd., hydrophobizing agent: DMDS, average particle diameter: 16 nm), and 1.0 part by mass of hydrophobic silica "RY - 50" (manufactured by Nippon Aerosil Co., Ltd., hydrophobizing agent: silicone oil, average particle diameter: 40 nm) were mixed in a Henschel mixer (manufactured by Mitsui Mining Co., Ltd.) at a rotational speed of 3000 r / min (peripheral speed 32 m / sec) for 3 minutes to obtain a toner.

[0140] Test Example 1 [Low - temperature fixability of toner] The toner was mounted on a device obtained by modifying the fixing device of a copying machine "AR - 505" (manufactured by Sharp Corporation) so that fixing outside the device was possible, and a printed matter was obtained in an unfixed state (printing area: 2 cm × 12 cm, adhesion amount: 0.5 mg / cm 2 ). Then, using a fixing machine adjusted so that the total fixing pressure was 40 kgf (fixing speed 300 mm / sec), while sequentially increasing the temperature of the fixing roll from 100 °C to 200 °C in 5 °C increments, a fixing test of the unfixed printed matter was conducted at each temperature. A cellophane adhesive tape "UNICEF cellophane" (manufactured by Mitsubishi Pencil Co., Ltd., width: 18 mm, JIS Z1522:2009) was attached to the image part of the obtained printed matter, passed through a fixing roller set at 30 °C, which was different from the fixing roll of the fixing machine, and then the tape was peeled off. The optical reflection density before and after peeling the tape was measured using a reflection densitometer "RD - 915" (manufactured by GretagMacbeth), and the temperature of the fixing roll at which the ratio of the two (after peeling / before pasting × 100) first exceeded 90% was taken as the minimum fixing temperature. The results are shown in Table 3. A lower minimum fixing temperature indicates better low - temperature fixability. Note that "CopyBond SF - 70NA" (manufactured by Sharp Corporation, 75 g / m 2 ) was used as the fixing paper.

[0141] Test Example 2 [Durability of toner] Toner was mounted on a printing press "Page Press N-4" (manufactured by Casio Computer Co., Ltd., fixing: contact fixing method, development: non-magnetic one-component development method, development roll diameter: 2.3 cm), and a pattern of diagonal stripes with a blackening rate of 5.5% was continuously printed in an environment of 32°C and 85% humidity. During the process, a solid black image was printed every 500 sheets, and the presence or absence of streaks on the image was confirmed. Printing was stopped when streaks occurred on the image, and it was carried out up to a maximum of 9000 sheets. The number of printed sheets until streaks were visually observed on the image was regarded as the number of sheets in which streaks occurred due to the fusion and fixation of toner on the development roll, and the durability was evaluated. The results are shown in Table 3. It can be judged that the higher the number of printed sheets until streaks occur, that is, the larger the number of printed sheets without streaks, the higher the durability of the toner. In the table, ">9000" means that no streaks were observed at the time of printing 9000 sheets.

[0142]

Table 3

[0143] From the above results, compared with Comparative Examples 1 and 2 in which the temperature on the discharge side of the kneaded product of the high-speed rotation roll of the open roll type biaxial kneader is outside the predetermined range, and Comparative Examples 3 to 5 using a crystalline polyester resin that does not use a predetermined raw material monomer, it can be seen that the toners of Examples 1 to 10 have good low-temperature fixability and durability.

Industrial Applicability

[0144] The toner for developing an electrostatic charge image obtained by the method of the present invention is suitably used for developing a latent image formed in an electrophotographic method, an electrostatic recording method, an electrostatic printing method, etc.

Claims

1. A method for producing an electrostatic charge image developing toner containing a crystalline polyester resin C, an amorphous resin A, and a release agent, wherein the crystalline polyester resin C is a polycondensate of an alcohol component containing an aliphatic diol having 8 to 10 carbon atoms and a carboxylic acid component containing an aliphatic dicarboxylic acid compound having 6 to 10 carbon atoms, and the method includes a step of melt-kneading a mixture containing the crystalline polyester resin C, the amorphous resin A, and the release agent using an open roll type twin-screw kneader having two rolls with different peripheral speeds, and a temperature on the kneaded product discharge side of the high-speed rotation roll of the open roll type twin-screw kneader is -20°C or higher and +15°C or lower than the melting point of the crystalline polyester resin C. A method for producing an electrostatic charge image developing toner.

2. The production method according to claim 1, wherein the content of the crystalline polyester resin C is 3% by mass or more and 40% by mass or less in the total amount of the crystalline polyester resin C and the amorphous resin A.

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