Binder resin for toner

Abstract

To provide a binder resin for a toner which is used in an electrophotographic toner that is excellent in hot offset resistance, development efficiency and suppression of occurrence of fogging, an electrophotographic toner which contains the binder resin for the toner, and a method for manufacturing the electrophotographic toner.SOLUTION: A binder resin for toner contains an amorphous polyester-based resin (A), wherein the amorphous polyester-based resin (A) is a silicone-modified polyester-based resin which is a reactant of a raw material component containing a bi- or higher valent carboxylic acid component, a bi- or higher valent alcohol component and modified silicone, the carboxylic acid component contains 7 mol% or more of an alkenylsuccinic acid, the modified silicone is modified silicone having at least one kind of functional group selected from an amino group, a carboxy group, an epoxy group and a carbinol group, and a softening point of the amorphous polyester-based resin (A) is 70°C or higher and 120°C or lower.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a toner binder resin used in an electrophotographic toner used for developing a latent image formed in an electrophotographic method, an electrostatic recording method, an electrostatic printing method, etc., an electrophotographic toner containing the toner binder resin, and a method for producing the electrophotographic toner.

Background Art

[0002] In the field of electrophotography, with the development of electrophotographic systems, there is a demand for the development of toners that can cope with high image quality and high speed. For example, Patent Document 1 discloses an electrophotographic toner containing toner particles, wherein the toner particles are a resin (A) which is a reaction product of an alcohol component containing a dihydric or higher alcohol, a carboxylic acid component containing a dicarboxylic acid compound having two or more carbon atoms, and a modified silicone having a hydroxy group, a carboxy group, or an epoxy group at one or both ends (however, when the modified silicone has a hydroxy group at one or both ends, the number average molecular weight of the resin (A) is 1,000 or more and 10,000 or less), and the volume median diameter (D 50 ) of the toner particles is 6.5 μm or less, and the electrophotographic toner is used in an electrophotographic apparatus using a belt fixing method or a free belt nip fixing method in a fixing device.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, although the toner described in Patent Document 1 is excellent in low-temperature fixability and hot offset resistance, there is room for improvement in development efficiency and the occurrence of fogging. The present invention relates to a toner binder resin used in an electrophotographic toner excellent in hot offset resistance, development efficiency, and suppression of fog generation, an electrophotographic toner containing the toner binder resin, and a method for producing the electrophotographic toner.

Means for Solving the Problems

[0005] The present invention relates to the following [1] to [3]. [1] A toner binder resin containing an amorphous polyester resin (A), wherein the amorphous polyester resin (A) is a silicone-modified polyester resin which is a reaction product of raw material components including a dicarboxylic acid component having two or more carboxyl groups, a diol component having two or more hydroxyl groups, and a modified silicone, the carboxylic acid component contains 7 mol% or more of alkenyl succinic acid, the modified silicone is a modified silicone having at least one functional group selected from an amino group, a carboxy group, an epoxy group, and a carbinol group, and the softening point of the amorphous polyester resin (A) is 70°C or higher and 120°C or lower, a toner binder resin. [2] An electrophotographic toner containing the toner binder resin according to [1]. [3] A method for producing an electrophotographic toner, which includes a step of melt-kneading the toner binder resin according to [1] to obtain a melt-kneaded product, and a step of pulverizing and classifying the melt-kneaded product to obtain toner mother particles.

Effects of the Invention

[0006] According to the present invention, it is possible to provide a toner binder resin used in an electrophotographic toner excellent in hot offset resistance, development efficiency, and suppression of fog generation, an electrophotographic toner containing the toner binder resin, and a method for producing the electrophotographic toner.

Modes for Carrying Out the Invention

[0007] [Toner Binder Resin] The binder resin for toner according to an embodiment of the present invention contains an amorphous polyester resin (A) (hereinafter also simply referred to as "resin (A)"), which is a reaction product of raw material components including a dicarboxylic acid component or higher, a diol component or higher, and a modified silicone. The carboxylic acid component contains 7 mol% or more of alkenyl succinic acid. The modified silicone is a modified silicone having at least one functional group selected from an amino group, a carboxy group, an epoxy group, and a carbinol group. The softening point of the amorphous polyester resin (A) is 70°C or higher and 120°C or lower. According to the above configuration, it is possible to provide a binder resin for toner that gives an electrophotographic toner excellent in hot offset resistance, development efficiency, and suppression of fogging.

[0008] The reason for obtaining the effects of the present invention is not clear, but it is considered as follows. By introducing a low-polarity modified silicone into the binder resin of the electrophotographic toner to reduce the surface tension of the toner, the hot offset resistance of the toner is improved. However, with respect to the high-polarity polyester resin or the alcohol component and carboxylic acid component, which are their raw material monomers, the low-polarity modified silicone has low dispersibility, and a large amount of unreacted modified silicone remains when introducing a silicone unit into the binder resin. As a result, the unreacted modified silicone in the binder resin localizes on the toner surface, causing aggregation of the toner mother particles. As a result, there have been problems such as a decrease in fluidity, deterioration of development efficiency, and fogging. The amorphous polyester resin (A) contained in the binder resin for toner of the present invention is a silicone-modified polyester resin which is a reaction product of raw material components including a polyvalent carboxylic acid component containing a specific amount of alkenyl succinic acid, a polyvalent alcohol component, and a modified silicone. It is considered that alkenyl succinic acid increases the dispersibility of the modified silicone during the reaction, thereby reducing the content of unreacted modified silicone. Therefore, by enhancing the fluidity of the toner, it is considered possible to provide an electrophotographic toner that is excellent in suppressing development efficiency and fog generation in addition to the hot offset resistance brought about by the introduction of the modified silicone into the binder resin.

[0009] The definitions of various terms in this specification are shown below. The crystallinity of a resin is represented by a crystallinity index defined as the ratio of the softening point to the maximum peak temperature of endotherm measured by a differential scanning calorimeter (DSC), that is, "softening point (°C) / maximum peak temperature of endotherm (°C)". The "crystalline resin" refers to a resin having a crystallinity index of 0.6 or more and 1.4 or less. The "amorphous resin" refers to a resin in which no endothermic peak is observed by a differential scanning calorimeter (DSC), or, when an endothermic peak is observed, the crystallinity index is less than 0.6 or more than 1.4. The maximum peak temperature of endotherm refers to the temperature of the peak with the largest peak area among the endothermic peaks observed under the conditions of the measurement method described in the examples. The crystallinity of a resin can be adjusted by the type and ratio of raw material monomers, and production conditions (for example, reaction temperature, reaction time, cooling rate), etc. The "alkylene oxide adduct of bisphenol A" means the entire structure in which an alkylene oxide is added to 2,2-bis(4-hydroxyphenyl)propane. The "carboxylic acid component" includes not only carboxylic acids but also their anhydrides and their alkyl esters having 1 to 3 carbon atoms. That is, in this specification, when only the name of a carboxylic acid is described, it is assumed that the anhydride of the carboxylic acid and alkyl esters having 1 to 3 carbon atoms are also included. "Volume median particle diameter (D50 )” refers to the particle size at which the cumulative volume frequency calculated by volume fraction reaches 50% when calculated from the smaller particle size.

[0010] [Amorphous polyester resin (A)] The amorphous polyester resin (A) is a silicone-modified polyester resin which is a reaction product of raw material components including a dicarboxylic acid component having two or more valences, a diol component having two or more valences, and a modified silicone.

[0011] (Dicarboxylic acid component having two or more valences) The carboxylic acid component contains alkenyl succinic acid. The carbon number of the alkenyl group of the alkenyl succinic acid is preferably 6 or more, more preferably 7 or more, still more preferably 8 or more, and preferably 24 or less, more preferably 20 or less, still more preferably 16 or less, from the viewpoint that the toner is excellent in development efficiency and suppression of fog generation. Among them, dodecenyl succinic acid, octenyl succinic acid, and octadecenyl succinic acid are preferable, and dodecenyl succinic acid is more preferable. Further, the alkenyl group of the alkenyl succinic acid preferably has a branched structure from the viewpoint that the toner is more excellent in development efficiency and suppression of fog generation. The alkenyl succinic acid in the carboxylic acid component may be used alone or in combination of two or more.

[0012] The total content of the alkenyl succinic acid in the dicarboxylic acid component having two or more valences is 7 mol% or more from the viewpoint that the toner is excellent in development efficiency and suppression of fog generation, and preferably 40 mol% or less, more preferably 37 mol% or less, still more preferably 35 mol% or less from the viewpoints of the binder resin for toner and the storage stability of the toner.

[0013] (Carboxylic acid component other than alkenyl succinic acid) Examples of the carboxylic acid other than the alkenyl succinic acid contained in the dicarboxylic acid component having two or more valences include aromatic dicarboxylic acids, aliphatic dicarboxylic acids, and polyvalent carboxylic acids having three or more valences. The carboxylic acid component other than the alkenyl succinic acid may be used alone or in combination of two or more. Examples of the aromatic dicarboxylic acid include phthalic acid, isophthalic acid, terephthalic acid and the like. Among these, from the viewpoint that the toner is excellent in hot offset resistance, development efficiency, and suppression of fog generation, the aromatic dicarboxylic acid is preferably isophthalic acid, terephthalic acid, more preferably terephthalic acid. Examples of the aliphatic dicarboxylic acid include linear, branched, or alicyclic aliphatic dicarboxylic acids such as fumaric acid, adipic acid, sebacic acid, maleic acid, azelaic acid, succinic acid, cyclohexanedicarboxylic acid and the like. Examples of the polyvalent carboxylic acid having a valence of 3 or more include trimellitic acid, 2,5,7-naphthalenetricarboxylic acid, pyromellitic acid, and aconitic acid. Among these, from the viewpoint that the toner is excellent in hot offset resistance, development efficiency, and suppression of fog generation, the polyvalent carboxylic acid having a valence of 3 or more is preferably trimellitic acid.

[0014] The total content of carboxylic acids other than alkenyl succinic acid in the carboxylic acid component is preferably 60 mol% or more, more preferably 63 mol% or more, still more preferably 65 mol% or more, and preferably 93 mol% or less from the viewpoint that the toner is excellent in hot offset resistance, development efficiency, and suppression of fog generation.

[0015] (Divalent or higher polyhydric alcohol component) Examples of the alcohol contained in the divalent or higher polyhydric alcohol component include diols and polyhydric alcohols having a valence of 3 or more. Examples of the diol include aromatic diols, aliphatic diols, and alicyclic diols. The divalent or higher polyhydric alcohol component can be used alone or in combination of two or more.

[0016] Examples of the aromatic diol include alkylene oxide adducts of bisphenol A. The alkylene oxide adduct of bisphenol A is preferably a compound represented by the following formula (I) from the viewpoint that the toner is excellent in hot offset resistance, development efficiency, and suppression of fog generation.

[0017] [Chemical formula]

[0018] In the above formula (I), OR 1 , and R 2 O are all alkyleneoxy groups. From the viewpoint that the toner is excellent in hot offset resistance, development efficiency, and suppression of fogging, preferably, each is independently an alkyleneoxy group having 1 or more and 4 or less carbon atoms, and more preferably, an ethyleneoxy group or a propyleneoxy group. x and y correspond to the number of moles of alkylene oxide added. Further, from the viewpoint of reactivity with the carboxylic acid component, the average value of the sum of x and y is preferably 2 or more. Also, from the same viewpoint, the average value of the sum of x and y is preferably 7 or less, more preferably 5 or less, and still more preferably 3 or less. x moles of OR 1 and y moles of R 2 O may be the same or different from each other, but from the viewpoint that the toner is excellent in hot offset resistance, development efficiency, and suppression of fogging, it is preferably the same. The alkylene oxide adduct of bisphenol A may be used alone or in combination of two or more. The alkylene oxide adduct of bisphenol A is preferably at least one selected from the propylene oxide adduct of bisphenol A and the ethylene oxide adduct of bisphenol A.

[0019] Examples of the aliphatic diol include ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 2,3-butanediol, 1,4-butanediol, 1,2-pentanediol, 1,4-pentanediol, 2,4-pentanediol, 1,2-hexanediol, 1,5-hexanediol, 2,5-hexanediol, 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,12-dodecanediol, 1,14-tetradecanediol, 1,16-hexadecanediol, 3,3-dimethyl-1,2-butanediol, and the like. Examples of the alicyclic diol include cyclohexanediol, cyclohexanedimethanol, hydrogenated bisphenol A, and the like. Examples of the polyhydric alcohol having a valency of 3 or more include glycerin, pentaerythritol, trimethylolpropane, sorbitol, sorbitan, and the like. Alcohols other than alkenyl succinic acid may be used alone or in combination of two or more.

[0020] From the viewpoint that the toner is excellent in hot offset resistance, development efficiency, and suppression of fog generation, the content of the alkylene oxide adduct of bisphenol A in the alcohol component is preferably 60 mol% or more, more preferably 80 mol% or more, still more preferably 90 mol% or more, even more preferably 95 mol% or more, and preferably 100 mol% or less, more preferably 100 mol%.

[0021] The equivalent ratio (COOH group / OH group) of the carboxyl group (COOH group) of the carboxylic acid component to the hydroxyl group (OH group) of the alcohol component is preferably 0.7 or more, more preferably 0.8 or more, and preferably 1.3 or less, more preferably 1.2 or less.

[0022] (Modified silicone) The modified silicone contains at least one selected from a modified silicone having a repeating unit represented by formula (1) and a repeating unit represented by formula (2), and a modified silicone having a repeating unit represented by formula (2) and a structure represented by formula (3). From the viewpoint that the toner is excellent in hot offset resistance, development efficiency, and suppression of fogging, the modified silicone is preferably a modified silicone having a repeating unit represented by formula (1) and a repeating unit represented by formula (2), that is, a modified silicone having at least one functional group selected from an amino group, a carboxy group, an epoxy group, and a carbinol group in the side chain.

[0023] [Chemical formula] 〔In formula (1), each R is independently a hydrocarbon group having 1 to 6 carbon atoms, each R' is independently an alkylene group having 1 to 10 carbon atoms, a is 1 or 0, X is independently a group containing an amino group, a carboxy group, an epoxy group, or a hydroxy group, and * is a bonding site.〕

[0024] [Chemical formula] 〔In formula (2), each R is independently a hydrocarbon group having 1 to 6 carbon atoms, and * is a bonding site.〕

[0025] *-SiR 3-b (R''-X) b (3) 〔In formula (3), each R is independently a hydrocarbon group having 1 to 6 carbon atoms, each R'' is independently an alkylene group having 1 to 10 carbon atoms, b is an integer of 1 to 3, X is independently a group containing an amino group, a carboxy group, an epoxy group, or a hydroxy group, and * is a bonding site with the repeating unit represented by formula (2).〕

[0026] Incidentally, the repeating unit represented by formula (1) and the repeating unit represented by formula (2) may be random or block and are not particularly limited.

[0027] In formulas (1) to (3), the number of carbon atoms of the hydrocarbon group of R is 6 or less, preferably 4 or less, more preferably 3 or less, still more preferably 2 or less, and still more preferably 1. Examples of the hydrocarbon group of R include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a tert-butyl group, a pentyl group, and a phenyl group. Among these, a methyl group is preferable.

[0028] In formulas (1) and (3), the number of carbon atoms of the alkylene groups of R' and R'' is 10 or less, preferably 8 or less, more preferably 5 or less, still more preferably 4 or less, and still more preferably 3 or less, and is preferably 1 or more. Examples of the alkylene groups of R' and R'' include a methanediyl group, an ethane-1,2-diyl group, an ethane-1,1-diyl group, an n-propane-1,3-diyl group, and an n-propane-1,2-diyl group. Among these, a methanediyl group, an ethane-1,2-diyl group, an n-propane-1,3-diyl group, and an n-propane-1,2-diyl group are preferable.

[0029] X is each independently a group having an amino group, a carboxy group, an epoxy group, or a hydroxy group, and is preferably an amino group, a hydroxy group, a hydroxyalkyloxy group, a carboxy group, a carboxyalkyloxy group, an epoxy group, a glycidyl group, a glycidyloxy group, or an alicyclic epoxy group. The hydroxyalkyloxy group may have a plurality of hydroxy groups, and the carboxyalkyloxy group may have a plurality of carboxy groups. Among them, from the viewpoint of reactivity with the carboxy group of a dicarboxylic acid or higher, X is preferably a group having an amino group.

[0030] The modified silicone contains 40 or less, preferably 20 or less, more preferably 10 or less, and 1 or more of the repeating units represented by formula (1). Further, it contains 500 or less, preferably 450 or less, more preferably 400 or less of the repeating unit represented by the formula (2), and preferably contains 10 or more, preferably 30 or more, more preferably 50 or more.

[0031] The functional group equivalent of the modified silicone is preferably 300 g / mol or more, more preferably 500 g / mol or more, still more preferably 1,000 g / mol or more, still more preferably 2,000 g / mol or more, and preferably 10,000 g / mol or less, more preferably 8,000 g / mol or less, still more preferably 6,000 g / mol or less. Note that the functional group equivalent means the mass of the modified silicone per mole of the functional group.

[0032] From the viewpoint that the toner is excellent in hot offset resistance, development efficiency, and suppression of fogging, the kinematic viscosity of the modified silicone is preferably 20 mm 2 / s or more, more preferably 90 mm 2 / s or more, still more preferably 1,000 mm 2 / s or more at 25°C, and preferably 20,000 mm 2 / s or less, more preferably 5,000 mm 2 / s or less, still more preferably 2,000 mm 2 / s or less. The kinematic viscosity of the modified silicone may adopt the catalog value, or can also be measured, for example, using a fully automatic micro kinematic viscometer (manufactured by Bisco Co., Ltd.).

[0033] Examples of the modified silicone include modified silicones having an amino group in the side chain (commercially available products include, for example, "KF-864" and "KF-865" (manufactured by Shin-Etsu Chemical Co., Ltd.)), modified silicones having amino groups at both ends (commercially available products include, for example, "KF-8008" and "KF-8012" (manufactured by Shin-Etsu Chemical Co., Ltd.)), modified silicones having an amino group at one end; modified silicones having a carboxy group in the side chain (commercially available products include, for example, "X-22-3701E" (manufactured by Shin-Etsu Chemical Co., Ltd.), "BY16-880" (manufactured by Toray Dow Corning)), modified silicones having carboxy groups at both ends (commercially available products include, for example, "X-22-162C" (manufactured by Shin-Etsu Chemical Co., Ltd.)), modified silicones having a carboxy group at one end (commercially available products include, for example, "X-22-3710" (manufactured by Shin-Etsu Chemical Co., Ltd.)); modified silicones having an epoxy group in the side chain (commercially available products include "KF-1001" and "X-22-343" (manufactured by Shin-Etsu Chemical Co., Ltd.)), modified silicones having epoxy groups at both ends (commercially available products include "X-22-163B" and "X-22-169B" (manufactured by Shin-Etsu Chemical Co., Ltd.)), modified silicones having an epoxy group at one end (commercially available products include, for example, "X-22-173BX" (manufactured by Shin-Etsu Chemical Co., Ltd.)); modified silicones having a hydroxy group in the side chain (commercially available products include "X-22-4015" and "X-22-4039" (manufactured by Shin-Etsu Chemical Co., Ltd.)), modified silicones having hydroxy groups at both ends (commercially available products include "KF-6003" and "KF-6002" (manufactured by Shin-Etsu Chemical Co., Ltd.)), modified silicones having a hydroxy group at one end (commercially available products include "X-22-170BX" and "X-22-170DX" (manufactured by Shin-Etsu Chemical Co., Ltd.)).

[0034] When the modified silicone is a modified silicone having a group containing an amino group, in the repeating unit represented by the formula (1) and the structure represented by the formula (3), *-(R’) a Examples of the group represented by -X and the group represented by -(R''-X) include the following substituents 1a-1 to 1a-3.

[0035]

Chemical formula

[0036] When the modified silicone is a modified silicone having a group containing a hydroxy group, in the repeating unit represented by the formula (1) and the structure represented by the formula (3), *-(R’) a Examples of the group represented by -X and the group represented by -(R''-X) include the following substituents 1b-1 to 1b-3. Among these, the substituent 1b-1 or the substituent 1b-2 is preferable, and the substituent 1b-1 is more preferable.

[0037]

Chemical formula

[0038] When the modified silicone is a modified silicone having a group containing an epoxy group, in the repeating unit represented by the formula (1) and the structure represented by the formula (3), it is preferable that X and Y are a glycidyl group, a glycidyloxy group, and an alicyclic epoxy group, *-(R’) a Examples of the group represented by -X and the group represented by -(R''-X) include the following substituents 1b-4 to 1b-6. Among these, the substituent 1b-4 is preferable.

[0039]

Chemical formula

[0040] When the modified silicone is a modified silicone having a group containing a carboxy group, in the repeating unit represented by the formula (1) and the structure represented by the formula (3), it is preferable that X and Y are a carboxy group or a carboxyalkyloxy group, *-(R’) a Examples of the group represented by -X and the group represented by -(R''-X) include the following substituent 1b-7.

[0041]

Chemical formula

[0042] (Method for producing amorphous polyester resin (A)) Resin (A) is produced, for example, by a method of polycondensing raw material components. In the polycondensation reaction, if necessary, an esterification catalyst such as tin(II) bis(2-ethylhexanoate), dibutyltin oxide, or titanium diisopropoxide bistriethanolamineate is used in an amount of 0.01 parts by mass or more and 5 parts by mass or less based on 100 parts by mass in total of a divalent or higher carboxylic acid component and a divalent or higher alcohol component; an esterification co-catalyst such as gallic acid (the same as 3,4,5-trihydroxybenzoic acid) is used in an amount of 0.001 parts by mass or more and 0.5 parts by mass or less based on 100 parts by mass in total of an aliphatic diol, an aliphatic dicarboxylic acid, an aliphatic monoalcohol, and an aliphatic monocarboxylic acid, and the reaction may be carried out. When using a monomer having an unsaturated bond such as fumaric acid in polycondensation, a radical polymerization inhibitor is preferably used in an amount of 0.001 parts by mass or more and 0.5 parts by mass or less based on 100 parts by mass in total of an alcohol component and a carboxylic acid component, if necessary. Examples of the radical polymerization inhibitor include 4-tert-butylcatechol. The reaction temperature is preferably 120 °C or higher, more preferably 160 °C or higher, still more preferably 180 °C or higher, and preferably 250 °C or lower, more preferably 240 °C or lower. The reaction may be carried out in an inert gas atmosphere.

[0043] (Physical properties of amorphous polyester resin (A)) The softening point of resin (A) is 70 °C or higher, preferably 80 °C or higher, more preferably 90 °C or higher, and 120 °C or lower, preferably 115 °C or lower, more preferably 110 °C or lower, from the viewpoint that the toner is excellent in hot offset resistance, development efficiency, and suppression of fogging. The glass transition temperature of resin (A) is preferably 40 °C or higher, more preferably 45 °C or higher, still more preferably 50 °C or higher, and preferably 100 °C or lower, more preferably 95 °C or lower, still more preferably 90 °C or lower, from the viewpoints of the toner having excellent hot offset resistance, development efficiency, and suppression of fogging.

[0044] The softening point and glass transition temperature of resin (A) can be appropriately adjusted according to the types and amounts of the raw material components, and production conditions such as reaction temperature, reaction time, and cooling rate, and are determined by the methods described in the examples below. When two or more types of resin (A) are used in combination, it is preferable that the softening point and glass transition temperature of the resin (A) obtained as their mixture are within the above ranges, respectively.

[0045] The binder resin for toner of the present invention may contain, in addition to resin (A), resins such as amorphous polyester resins, crystalline polyester resins, acrylic resins such as styrene-acrylic copolymers, and polyurethane resins, as long as the effects of the present invention are not impaired. Other amorphous polyester resins of resin (A) are not particularly limited as long as they contain a polycondensate of an alcohol component and a carboxylic acid component, and examples include polyester resins composed of polycondensates and modified polyester resins. Examples of the modified polyester resin include composite resins containing a polyester resin segment and an addition polymer resin segment, urethane-modified products of polyester resins, and epoxy-modified products of polyester resins. As other amorphous polyester resins of resin (A), polyester resins composed of a polycondensate of an alcohol component and a carboxylic acid component are preferable.

[0046] The content of resin (A) in the binder resin for toner is preferably 40% by mass or higher, more preferably 45% by mass or higher, still more preferably 50% by mass or higher, and preferably 80% by mass or lower, more preferably 75% by mass or lower, still more preferably 70% by mass or lower, from the viewpoints of the toner having excellent hot offset resistance, development efficiency, and suppression of fogging.

[0047] [Electrophotographic toner] The electrophotographic toner according to one embodiment of the present invention (hereinafter, also simply referred to as "toner") is a toner containing a binder resin, and the binder resin contains the binder resin for toner of the present invention described above. According to the present invention, it is possible to provide an electrophotographic toner excellent in hot offset resistance, development efficiency, and suppression of fog generation. The toner for electrostatic charge image development contains at least the above-mentioned binder resin for toner and a colorant, and in addition to this, other components such as a release agent and a charge control agent may be contained. Further, the toner for electrostatic charge image development preferably includes toner mother particles and an external additive externally added to the toner mother particles.

[0048] [Colorant] As the colorant, all dyes, pigments, etc. used as colorants for toner can be used, and carbon black, phthalocyanine blue, permanent brown FG, brilliant fast scarlet, pigment green B, rhodamine-B base, solvent red 49, solvent red 146, solvent blue 35, quinacridone, carmine 6B, disazo yellow, etc. can be used, and the toner of the present invention may be either a black toner or other color toners.

[0049] From the viewpoint that the toner is more excellent in hot offset resistance, development efficiency, and suppression of fog generation, the content of the colorant is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, still more preferably 3 parts by mass or more, and preferably 20 parts by mass or less, more preferably 15 parts by mass or less, still more preferably 10 parts by mass or less with respect to 100 parts by mass of the total amount of the binder resin. Also, from the viewpoint that the toner is more excellent in hot offset resistance, development efficiency, and suppression of fog generation, the content of the colorant is preferably 0.5 parts by mass or more, more preferably 1 part by mass or more, still more preferably 3 parts by mass or more, and preferably 20 parts by mass or less, more preferably 15 parts by mass or less, still more preferably 10 parts by mass or less with respect to the toner mother particles.

[0050] <Release agent> Examples of the release agent include hydrocarbon wax, ester wax, silicone wax, and fatty acid amide wax.

[0051] The melting point of the release agent is preferably 60°C or higher, more preferably 70°C or higher, and preferably 160°C or lower, more preferably 150°C or lower, and still more preferably 140°C or lower. When two or more release agents are used in combination, the melting point of each release agent is preferably within the above-mentioned range.

[0052] When the toner mother particle contains a release agent, the content is preferably 0.5 part by mass or more, more preferably 1.0 part by mass or more, still more preferably 1.5 part by mass or more, and preferably 10 parts by mass or less, more preferably 5 parts by mass or less, and still more preferably 3 parts by mass or less with respect to 100 parts by mass of the total amount of the binder resin.

[0053] <Charge control agent> The charge control agent may contain either a positive charge control agent or a negative charge control agent. Examples of the positive charge control agent 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", "Bontron N-79" (manufactured by Orient Chemical Industries Co., Ltd., etc.); triphenylmethane dyes containing a tertiary amine in the side chain, quaternary ammonium salt compounds such as "Bontron P-51" (manufactured by Orient Chemical Industries Co., Ltd.), cetyltrimethylammonium bromide, "COPY CHARGE PX VP435" (manufactured by Clariant, etc.); polyamine resins such as "AFP-B" (manufactured by Orient Chemical Industries Co., 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" (manufactured by Fujikura Kasei Co., Ltd., etc.).

[0054] Examples of the negative charge control agent 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.; and organometallic compounds. The charge control agent to be used may be appropriately selected according to the characteristics of the printing machine using the toner, the type of the colorant, and the like.

[0055] 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, still more preferably 0.5 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, based on 100 parts by mass of the total amount of the binder resin.

[0056] [Method for producing toner] The method for producing the toner according to an embodiment of the present invention may be any known method such as a melt-kneading method, an emulsion phase inversion method, a polymerization method, an emulsion aggregation method, etc., but from the viewpoint of productivity and the like, a method for producing a pulverized toner by a melt-kneading method is preferable. When producing a pulverized toner by a melt-kneading method, the method for producing the toner includes a step of melt-kneading the binder resin for toner to obtain a melt-kneaded product, and a step of pulverizing and classifying the obtained melt-kneaded product to obtain toner mother particles. The step of obtaining the melt-kneaded product can be carried out by a known method. For example, after uniformly mixing raw materials such as the above-mentioned binder resin for toner, colorant, and optionally a release agent and a charge control agent, etc. with a mixer such as a Henschel mixer, a melt-kneaded product can be produced by melt-kneading with a closed kneader, a single-screw or twin-screw extruder, an open roll type kneader, etc. In the step of melt-kneading, the melt-kneading temperature is preferably 80°C or higher, more preferably 90°C or higher, and preferably 200°C or lower, more preferably 180°C or lower. The step of pulverizing and classifying the melt-kneaded product to obtain toner mother particles can be carried out by a known method. The method for producing toner may have a step of cooling the melt-kneaded product between the step of obtaining the melt-kneaded product and the step of pulverizing and classifying the melt-kneaded product to obtain toner mother particles.

[0057] The volume median particle diameter (D 50 ) of the toner mother particles is preferably 2 μm or more, more preferably 3 μm or more, still more preferably 4 μm or more from the viewpoint of excellent development efficiency and suppression of fog generation of the toner, and is 8 μm or less, preferably 7 μm or less, more preferably 6.8 μm or less from the viewpoint of hot offset resistance.

[0058] It is preferable that a fluidizing agent or the like is added and treated on the surface of the toner mother particles as an external additive. Examples of the external additive include fine particles of inorganic materials such as hydrophobic silica, titanium oxide fine particles, alumina fine particles, cerium oxide fine particles, carbon black, and fine particles of polymers such as polycarbonate, polymethyl methacrylate, and silicone resin. Among these, hydrophobic silica is preferable. When using an external additive, the addition amount of the external additive is preferably 0.5 part by mass or more with respect to 100 parts by mass of the toner mother particles, and preferably 5 parts by mass or less, more preferably 4 parts by mass or less, still more preferably 3 parts by mass or less.

[0059] Toner is used for developing latent images formed, for example, in electrophotography, electrostatic recording, electrostatic printing, etc. Toner can be used as a one-component developer or mixed with a carrier to be used as a two-component developer.

[0060] (Recording medium) The recording medium for printing the toner of the present invention is not particularly limited, and examples include ordinary paper from thin paper to thick paper, high-quality paper, coated printing paper such as art paper and coated paper, commercially available Japanese paper, postcard paper, synthetic paper, and the like.

Examples

[0061] Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited by these examples. Physical properties such as those of resins were measured by the following methods. In notations such as “alkylene oxide (X)”, the numerical value X within the parentheses means the average number of moles of alkylene oxide added.

[0062] [Measurement method] 〔Softening point of resin〕 Using a flow tester “CFT-500D” (manufactured by Shimadzu Corporation), while heating 1 g of the sample at a heating rate of 6 °C / min, a load of 1.96 MPa was 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 was plotted against the temperature, and the temperature at which half of the sample flowed out was taken as the softening point.

[0063] 〔Glass transition temperature of amorphous resin〕 Using a differential scanning calorimeter “Q-20” (manufactured by TA Instruments Japan Co., Ltd.), 0.01 to 0.02 g of the sample was weighed into an aluminum pan, heated to 200 °C, and then cooled from that temperature to 0 °C at a cooling rate of 10 °C / min. Next, the sample was heated at a heating rate of 10 °C / min, and the temperature at the intersection of the extension line of the baseline below the highest peak temperature of the endotherm and the tangent line showing the maximum slope from the rising part of the peak to the apex of the peak was taken as the glass transition temperature.

[0064] [Toner Evaluation] [Hot Offset Resistance] The printer "MICROLINE 5400" (manufactured by OKI Electric Industry Co., Ltd.) was modified to be able to obtain an unfixed image, filled with toner, and an unfixed image of a solid 2 cm square was printed. At that time, as the fixing paper, thin paper (C2 paper, manufactured by Fujifilm Business Innovation, basis weight: 70 g / m 2 , paper thickness: 89 μm) that is more likely to cause hot offset was used. Using an externally mounted fixing device modified from "MICROLINE 3010" (manufactured by OKI Electric Industry Co., Ltd.), while raising the temperature of the fixing roll from 100°C to 200°C in 5°C increments at a rotational speed of the fixing roll of 150 mm / sec, the unfixed image was fixed at each temperature to obtain a fixed image. The obtained fixed images at 100°C to 200°C were visually inspected, and the highest temperature of the fixing roll at which no hot offset occurred was defined as the maximum fixing temperature. The higher the obtained temperature, the better the hot offset resistance.

[0065] [Development Efficiency] The development efficiency was calculated by measuring the amount of toner developed from the developing roll onto the photoreceptor, and the developability was evaluated according to the following evaluation criteria. The amount of toner on the developing roll was measured using a Q / m meter (manufactured by TREK: Model 210HS). The nozzle of the Q / m meter was gently pressed against the toner layer on the developing roll, and the toner was suctioned for an area equal to the nozzle diameter. This was repeated 10 times, and the weight of the suctioned toner was measured. Furthermore, the toner on the photoreceptor after development was suctioned in the same manner to measure the amount of developed toner, and the development efficiency was calculated according to the following formula. When evaluating in full color, the evaluation was performed using the average value of the four colors. [Development Efficiency (%)] = {Amount of toner on photoreceptor (mg / 10 locations) / Amount of toner on developing roller (mg / 10 locations)} × 100 (Evaluation Criteria) A: Development efficiency is 90 - 100% B: Development efficiency is 80% or more and less than 90% C: Development efficiency is 60% or more and less than 80% D: Development efficiency is 40% or more and less than 60% E: Development efficiency is less than 40%

[0066] 〔Suppression of fog generation〕 Toner was mounted on a non-magnetic one-component developing device "MICROLINE 5400" (manufactured by Oki Electric Industry Co., Ltd.), left standing for 12 hours in an environment of 40°C and 80% relative humidity, and then printing on white paper (printing rate 0%) was performed. After that, the toner remaining on the organic photoreceptor (OPC) drum was collected by attaching "Scotch mending tape" (3M Japan Co., Ltd., width: 18 mm) to form a sample. The difference in image density between the sample and the mending tape itself was measured using an image density measuring instrument "GREGSPM50" (manufactured by Gretag), and ΔE (=(L *2 +a *2 +b *2 )) 1 / 2 ) was measured to evaluate the suppression of fog generation. The smaller the ΔE, the better the suppression of fog generation.

[0067] 〔Production of amorphous polyester resin (A)〕 Production Example A1 (Resin A-1) The inside of a 10 L four-necked flask equipped with a nitrogen inlet tube, a dehydrating tube, a stirrer, and a thermocouple was purged with nitrogen, and 3,405 g of a propylene oxide (2.2) adduct of bisphenol A, 3,162 g of an ethylene oxide (2.2) adduct of bisphenol A, 1,938 g of terephthalic acid, 1495 g of branched dodecenyl succinic anhydride, 1000 g of silicone "KF-864" (manufactured by Shin-Etsu Chemical Co., Ltd.), and 50 g of tin(II) bis(2-ethylhexanoate) were added. While stirring under a nitrogen atmosphere, the temperature was raised to 235°C and held at 235°C for 6 hours. Then, the pressure inside the flask was reduced, and the reaction was carried out to the softening point shown in Table 1 at 8 kPa to obtain Resin A-1. The physical properties are shown in Table 1.

[0068] Production Examples A2 to A10, and Comparative Production Examples A'1 to A'3 [Resins A-2 to A-10, and A'-1 to A'-3] Resins A-2 to A-10, and Resins A'-1 to A'-3 were obtained in the same manner as in Production Example 1 except that the raw material components and their amounts were changed as shown in Table 1. The physical properties are shown in Table 1.

[0069] In addition, the alkenyl succinic acids and modified silicones used in Production Examples A1 to A10 and Comparative Production Examples A'1 to A'3 are as follows. · DDSA-C: Dodecenyl succinic anhydride having a branched structure in the alkenyl group · DDSA: Linear dodecenyl succinic anhydride · OSA: Linear octenyl succinic anhydride · ODSA: Linear octadecenyl succinic anhydride · KF-864: Modified silicone "KF-864" (silicone having a monoamino group in the side chain, kinematic viscosity (25 °C) = 1,700 mm 2 / s, functional group equivalent = 3,800 g / mol, manufactured by Shin-Etsu Chemical Co., Ltd.) · KF-865: Modified silicone "KF-865" (silicone having a monoamino group in the side chain, kinematic viscosity (25 °C) = 110 mm 2 / s, functional group equivalent = 5,000 g / mol, manufactured by Shin-Etsu Chemical Co., Ltd.) · KF-6003: Modified silicone oil "KF-6003" (silicone having carbinol groups (hydroxy groups) at both ends, kinematic viscosity (25 °C) = 110 mm 2 / s, functional group equivalent = 2500 g / mol, manufactured by Shin-Etsu Chemical Co., Ltd.) · KF-8012: Modified silicone oil "KF-8012" (silicone having amino groups at both ends, kinematic viscosity (25 °C) = 90 mm 2 / s, functional group equivalent = 2,200 g / mol, manufactured by Shin-Etsu Chemical Co., Ltd.) · KF-1001: Modified silicone oil "KF-1001" (silicone having an epoxy group in the side chain, kinematic viscosity (25 °C) = 17,000 mm 2 / s, functional group equivalent = 3,500 g / mol, manufactured by Shin-Etsu Chemical Co., Ltd.) · X-22-162C: Modified silicone oil "X-22-162C" (silicone having carboxy groups at both ends, kinematic viscosity (25 °C) = 220 mm 2 / s, functional group equivalent 2,300 g / mol, manufactured by Shin-Etsu Chemical Co., Ltd.) · KF-96-50cs: Silicone oil "KF-96-50cs" (methylpolysiloxane without reactive functional groups, kinematic viscosity (25 °C) = 50 mm 2 / s, manufactured by Shin-Etsu Chemical Co., Ltd.)

[0070]

Table 1

[0071] 〔Production of amorphous polyester resin (B)〕 Production Example B1 (Resin B-1) The inside of a 10 L four-necked flask equipped with a nitrogen inlet tube, a dehydration tube, a stirrer, and a thermocouple was purged with nitrogen. 4,835 g of an adduct of bisphenol A and propylene oxide (2.2), 1,924 g of an adduct of bisphenol A and ethylene oxide (2.2), 2,293 g of terephthalic acid, and 50 g of tin(II) bis(2-ethylhexanoate) were added. While stirring under a nitrogen atmosphere, the temperature was raised to 235 °C and held at 235 °C for 6 hours. Then, the pressure inside the flask was reduced and held at 8 kPa for 1 hour. After that, after returning to atmospheric pressure, it was cooled to 220 °C, 947 g of trimellitic anhydride was added, and the reaction was carried out at 220 °C for 0.5 hour. Then, the pressure inside the flask was reduced, and the reaction was carried out at 20 kPa until the desired softening point was reached to obtain Resin B-1 as an amorphous polyester resin. The softening point of Resin B-1 was 139 °C, and the glass transition temperature was 57 °C.

[0072] Examples 1 to 10 and Comparative Examples 1 to 3 A total of 100 parts by mass of the binder resin shown in Table 2, 2.0 parts by mass of the positively chargeable charge control agent "Bontron N-79" (manufactured by Orient Chemical Industries, Ltd.), and 6.0 parts by mass of the colorant "Regal 330R" (manufactured by Cabot Corporation, carbon black) were added and preliminarily mixed well with a Henschel mixer. Then, using a co-rotating twin-screw extruder, melt-kneading was performed at a roll rotation speed of 200 r / min (circumferential speed 0.3 m / min) and a heating temperature inside the roll of 100°C. After cooling and coarsely pulverizing the obtained melt-kneaded product, melt-kneading was performed using a co-rotating twin-screw extruder with a total kneading length of 1,560 mm, a screw diameter of 42 mm, and a barrel inner diameter of 43 mm. The rotation speed of the screw was 200 r / min (circumferential speed 0.3 m / min), the set heating temperature inside the roll was 100°C, the temperature of the kneaded product was 160°C, the supply speed of the kneaded product was 10 kg / h, and the average residence time was about 18 seconds.

[0073] After cooling the kneaded product, it was coarsely pulverized to about 1 mm using a hammer mill (manufactured by Hosokawa Micron Corporation). The obtained coarsely pulverized product was finely pulverized at a supply rate of 4.0 kg / h using an impact plate type jet mill IDS-2 (manufactured by Nippon Pneumatic Mfg. Co., Ltd.), and the target volume median diameter (D 50 ) was set to 6.5 μm, and the pulverization pressure was adjusted to obtain toner mother particles.

[0074] 1 part by mass of hydrophobic silica "NAX-50" (manufactured by Nippon Aerosil Co., Ltd., hydrophobizing agent: HMDS, average particle diameter: 30 nm) was added to 100 parts by mass of the obtained toner mother particles and mixed with a Henschel mixer to obtain toner. For the toner obtained in each example and each comparative example, the above toner evaluation was performed. The results are shown in Table 2.

[0075]

Table 2

[0076] As shown in Table 2, from the results of the examples and comparative examples, the toner containing the binder resin for toner of the present invention was excellent in hot offset resistance, development efficiency, and suppression of fog generation. On the other hand, the toners of Comparative Examples 1 and 2 containing an amorphous polyester resin as a binder resin, in which the carboxylic acid component constituting the amorphous polyester resin does not contain alkenyl succinic acid or the content in the carboxylic acid component is less than 7 mol%, were excellent in hot offset resistance but inferior in development efficiency and suppression of fog generation. Also, the toner of Comparative Example 3 containing an unmodified silicone amorphous polyester resin as a binder resin was inferior in hot offset resistance, development efficiency, and suppression of fog generation.

Claims

1. A toner binder resin containing an amorphous polyester resin (A), wherein the amorphous polyester resin (A) is a silicone-modified polyester resin which is a reaction product of raw material components including a dicarboxylic acid component having two or more carboxyl groups, a diol component having two or more hydroxyl groups, and a modified silicone, wherein the carboxylic acid component contains 7 mol% or more of alkenyl succinic acid, wherein the modified silicone is a modified silicone having at least one functional group selected from an amino group, a carboxyl group, an epoxy group, and a carbinol group, wherein the softening point of the amorphous polyester resin (A) is 70°C or higher and 120°C or lower, A toner binder resin.

2. The toner binder resin according to claim 1, wherein the modified silicone is a silicone having at least one of the functional groups in a side chain.

3. The toner binder resin according to claim 1 or 2, wherein the modified silicone has at least an amino group as the functional group.

4. The toner binder resin according to any one of claims 1 to 3, wherein the alkenyl group of the alkenyl succinic acid has 6 to 24 carbon atoms.

5. The toner binder resin according to any one of claims 1 to 4, wherein the alkenyl group of the alkenyl succinic acid has a branched structure.

6. The toner binder resin according to any one of claims 1 to 5, wherein the content of the amorphous polyester resin (A) is 40% by mass or more and 80% by mass or less.

7. An electrophotographic toner containing the toner binder resin according to any one of claims 1 to 6.

8. A method for manufacturing an electrophotographic toner, comprising a step of melt-kneading the toner binder resin according to any one of claims 1 to 6 to obtain a melt-kneaded product, and a step of pulverizing and classifying the melt-kneaded product to obtain toner mother particles.

Images