Electrophotographic toner

Abstract

To provide: an electrophotographic toner which is excellent in hot offset resistance and laminate adhesion; and a method for manufacturing the electrophotographic toner.SOLUTION: An electrophotographic toner comprises a binder resin, wherein the binder resin comprises an amorphous polyester-based resin (A) which is a reaction product of raw material components containing a bi- or higher valent carboxylic acid component, a bi- or higher valent alcohol component and modified silicone, the carboxylic acid component comprises 5 mol% to 35 mol% of an alkenylsuccinic acid, the modified silicone is one having at least one functional group selected from an amino group, a carboxyl group, an epoxy group and a carbinol group, an insoluble matter when the amorphous polyester-based resin (A) is dissolved in methyl ethyl ketone is 1 mass% or more with respect to the mass of the amorphous polyester-based resin (A), and the content of the release agent is 0 pt.mass or more and less than 1 pt.mass, with respect to 100 pts.mass of the total amount of the binder resin.SELECTED DRAWING: None

Description

Technical Field

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

Background Art

[0002] In recent years, while the print-on-demand market has been growing, the demand for higher speed in electrophotographic technology has been increasing. Therefore, as one of the means to meet the requirement of higher speed, a toner using polyester as a binder resin is used to fix the toner on paper with less energy. However, as a result of reducing the viscosity of the toner in response to such a requirement for higher speed, there are problems such as deterioration of the separability between the fixing device and the toner image and deterioration of the hot offset resistance.

[0003] Therefore, in order to solve these problems, 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 or higher, 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).) as a binder resin, and the volume median diameter (D 50 ) of the toner particles is 6.5 μm or less, and is described as an electrophotographic toner used in an electrophotographic apparatus using a belt fixing method or a free belt nip fixing method in a fixing device.

[0004] Also, Patent Document 2 describes a toner having toner particles containing a binder resin and a polar group-containing olefin copolymer, wherein the binder resin contains a modified polyester having a silicone unit, and the polar group-containing olefin copolymer is a polymer having a polar unit and a polyolefin unit, and the polar unit is a unit derived from any compound selected from the group consisting of α,β-unsaturated carboxylic acids and their derivatives, unsaturated nitriles and their derivatives.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0006] In print-on-demand printing, in post-processing such as bookbinding, catalog production, and postal item production after printing, laminating may be performed after the toner fixing step to improve durability and texture. The toners described in Patent Documents 1 and 2 are excellent in hot offset resistance, but the laminating adhesiveness may decrease. The present invention relates to an electrophotographic toner excellent in hot offset resistance and laminating adhesion.

Means for Solving the Problems

[0007] The present invention relates to the following [1] to [2]. 〔1〕An electrophotographic toner containing a binder resin, wherein the binder resin contains an amorphous polyester resin (A) which is a reaction product of a raw material component containing a dicarboxylic acid component having two or more valences, an alcohol component having two or more valences, and a modified silicone, The carboxylic acid component contains 5 mol% or more and 35 mol% or less 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, When the amorphous polyester resin (A) is dissolved in methyl ethyl ketone, the insoluble matter is 1% by mass or more based on the mass of the amorphous polyester resin (A), The content of the release agent is 0 part by mass or more and less than 1 part by mass with respect to 100 parts by mass of the total amount of the binder resin, An electrophotographic toner. 〔2〕A method for producing an electrophotographic toner, comprising a step of melt-kneading a binder resin composition containing an amorphous polyester resin (A) which is a reaction product of raw material components including a dicarboxylic acid component, a dihydric or higher alcohol component, and a modified silicone to obtain a melt-kneaded product, and a step of pulverizing and classifying the melt-kneaded product to obtain toner mother particles, The carboxylic acid component contains 5 mol% or more and 35 mol% or less 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, When the amorphous polyester resin (A) is dissolved in methyl ethyl ketone, the insoluble matter is 1% by mass or more based on the mass of the amorphous polyester resin (A), The content of the release agent is 0 part by mass or more and less than 1 part by mass with respect to 100 parts by mass of the total amount of the binder resin in the binder resin composition, A method for producing an electrophotographic toner.

Advantages of the Invention

[0008] According to the present invention, it is possible to provide an electrophotographic toner excellent in hot offset resistance and laminate adhesion, and a method for producing an electrophotographic toner.

Embodiments for Carrying Out the Invention

[0009] [Electrophotographic Toner] An electrophotographic toner according to an embodiment of the present invention (hereinafter, also simply referred to as "toner") contains a binder resin containing an amorphous polyester resin (A) which is a reaction product of raw material components including a dicarboxylic acid component having a valence of 2 or more, a dihydric or higher alcohol component, and a modified silicone. The carboxylic acid component contains 5 mol% or more and 35 mol% or less 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 insoluble matter when the amorphous polyester resin (A) is dissolved in methyl ethyl ketone is 1% by mass or more based on the mass of the amorphous polyester resin (A). The content of the release agent is 0 parts by mass or more and less than 1 part by mass with respect to 100 parts by mass of the total amount of the binder resin. According to the above configuration, it is possible to provide an electrophotographic toner excellent in hot offset resistance and laminate adhesion.

[0010] The reason for obtaining the effect of the present invention is not clear, but it is considered as follows. For improving the laminate adhesion, unevenness is required in the toner image to such an extent that the laminate adhesive can sufficiently exhibit the anchor effect. In particular, a release agent widely used for imparting offset properties bleeds out to the surface of the toner image and fills and smoothes the uneven surface shape, so it is more advantageous not to use it from the viewpoint of laminate adhesion. As a technique for imparting hot offset resistance, the use of a silicone-modified polyester resin has been studied. However, in the prior art, since the dispersibility of low-polarity silicone in high-polarity polyester is low, the reaction does not proceed sufficiently, and the modified silicone remains unreacted, and these bleed out to the surface of the toner image during image fixing. Therefore, the toner image is smoothed, and even if the hot offset resistance is improved, the laminate adhesion is deteriorated. In contrast, in the present invention, an amorphous polyester resin (A), which is a reaction product of a raw material component containing a dicarboxylic acid component containing a specific amount of alkenyl succinic acid, a dihydric or higher alcohol component, and a modified silicone, is contained in the binder resin contained in the toner as the silicone-modified polyester resin. The alkenyl succinic acid increases the dispersibility of the modified silicone during the reaction, thereby reducing the content of unreacted modified silicone and suppressing the smoothing of the image surface due to bleed-out. At the same time, since the amorphous polyester resin (A) is a high molecular weight substance to the extent that it contains a specific amount of methyl ethyl ketone-insoluble matter, the resin is likely to maintain an appropriate uneven shape on the image surface even after the fixing step. As a result, it is considered that the toner substantially does not contain a release agent, has excellent hot offset resistance, and has improved laminate adhesion.

[0011] The definitions of various terms in this specification are shown below. The crystallinity of the 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 having the largest peak area among the endothermic peaks observed under the conditions of the measurement method described in the examples. The crystallinity of the resin can be adjusted by the type and ratio of the raw material monomers, and manufacturing 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 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 size (D 50 )" means the particle size at which the cumulative volume frequency calculated by volume fraction becomes 50% when calculated from the smaller particle size.

[0012] [Amorphous polyester resin (A)] The amorphous polyester resin (A) (hereinafter also simply referred to as "resin (A)") is a silicone-modified polyester resin which is a reaction product of raw material components including a dicarboxylic acid component, a dihydric alcohol component, and a modified silicone.

[0013] (Dicarboxylic acid component having two or more valences) The carboxylic acid component contains alkenyl succinic acid. From the viewpoint of excellent hot offset resistance and laminate adhesion, the carbon number of the alkenyl group of 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 22 or less, still more preferably 20 or less. Among them, dodecenyl succinic acid is preferable. Further, from the viewpoint of excellent hot offset resistance and laminate adhesion, the alkenyl group of alkenyl succinic anhydride preferably has a branched structure. The alkenyl succinic anhydride in the carboxylic acid component may be used alone or in combination of two or more.

[0014] From the viewpoint of excellent hot offset resistance and laminate adhesion, the total content of alkenyl succinic acid in the dicarboxylic acid component having two or more valences is 5 mol% or more, preferably 7 mol% or more, more preferably 10 mol% or more, still more preferably 20 mol% or more, and from the viewpoint of storage stability, 35 mol% or less, more preferably 33 mol% or less, still more preferably 30 mol% or less.

[0015] (Other carboxylic acid components) Examples of carboxylic acids other than alkenyl succinic acids containing a divalent or higher carboxylic acid component include aromatic dicarboxylic acids, aliphatic dicarboxylic acids, and trivalent or higher polycarboxylic acids. The other carboxylic acid components may be used singly or in combination of two or more. Examples of aromatic dicarboxylic acids include phthalic acid, isophthalic acid, terephthalic acid, etc. Among these, from the viewpoint of excellent hot offset resistance and laminate adhesion, the aromatic dicarboxylic acid is preferably isophthalic acid, terephthalic acid, and more preferably terephthalic acid. Examples of aliphatic dicarboxylic acids include linear, branched, or alicyclic aliphatic dicarboxylic acids such as fumaric acid, adipic acid, sebacic acid, maleic acid, azelaic acid, succinic acid, succinic acid substituted with an alkyl group having 1 to 20 carbon atoms, cyclohexanedicarboxylic acid, etc. Examples of trivalent or higher polycarboxylic acids include trimellitic acid, 2,5,7-naphthalenetricarboxylic acid, pyromellitic acid, aconitic acid, etc. Among these, from the viewpoint of excellent hot offset resistance and laminate adhesion, the trivalent or higher polycarboxylic acid is preferably trimellitic acid.

[0016] From the viewpoint of excellent hot offset resistance and laminate adhesion, 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 95 mol% or less, more preferably 93 mol% or less.

[0017] (Divalent or higher alcohol component) Examples of alcohols containing a divalent or higher alcohol component include diols and trivalent or higher polyalcohols. Examples of diols include aromatic diols, aliphatic diols, and alicyclic diols. The divalent or higher alcohol component can be used singly or in combination of two or more.

[0018] 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 viewpoints of excellent hot offset resistance and laminate adhesion.

[0019]

Chemical formula

[0020] In the above formula (I), OR 1 , and R 2 O are both alkyleneoxy groups, preferably each independently an alkyleneoxy group having 1 to 4 carbon atoms, 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 ORs 1 and y R 2 Os may be the same or different from each other, but are 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.

[0021] 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, neopentyl glycol, 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. Other alcohols may be used alone or in combination of two or more.

[0022] From the viewpoint of excellent hot offset resistance and laminate adhesion, 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%.

[0023] 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.

[0024] (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 of excellent hot offset resistance and laminate adhesion, 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.

[0025]

Chemical formula

[0026]

Chemical formula

[0027] *-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, each 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).〕

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] From the viewpoint that the toner has excellent hot offset resistance and laminate adhesion, 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 1000 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, and can also be measured using, for example, a fully automatic micro kinematic viscometer (manufactured by Bisco Tec Co., Ltd.).

[0035] 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.)).

[0036] 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.

[0037]

Chemical formula

[0038] 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.

[0039]

Chemical formula

[0040] 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, and *-(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.

[0041]

Chemical formula

[0042] 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, and *-(R’) a Examples of the group represented by -X and the group represented by -(R''-X) include the following substituent 1b-7.

[0043]

Chemical formula

[0044] Among the raw material components of resin (A), the content of the modified silicone is preferably 3 parts by mass or more, more preferably 5 parts by mass or more, still more preferably 8 parts by mass or more, and preferably 20 parts by mass or less, more preferably 15 parts by mass or less, still more preferably 12 parts by mass or less, based on 100 parts by mass of the total amount of the dihydric or higher alcohol component and the dihydric or higher carboxylic acid component.

[0045] (Method for producing amorphous polyester-based 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 part by mass or more and 5 parts by mass or less based on 100 parts by mass of the total amount of the dihydric or higher carboxylic acid component and the dihydric 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 part by mass or more and 0.5 part by mass or less based on 100 parts by mass of the total amount of the dihydric or higher carboxylic acid component and the dihydric or higher alcohol component, and the reaction may be carried out. When using a monomer having an unsaturated bond such as fumaric acid in the polycondensation, if necessary, a radical polymerization inhibitor is used in an amount of preferably 0.001 part by mass or more and 0.5 part by mass or less based on 100 parts by mass of the total amount of the dihydric or higher carboxylic acid component and the dihydric or higher alcohol component. 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.

[0046] (Physical properties of amorphous polyester-based resin (A)) From the viewpoint of excellent hot offset resistance and laminate adhesion, the softening point of resin (A) is preferably 110°C or higher, more preferably 115°C or higher, still more preferably 120°C or higher, and is 160°C or lower, preferably 150°C or lower, more preferably 145°C or lower. From the viewpoint of excellent hot offset resistance and laminate adhesion, 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 is preferably 100°C or lower, more preferably 95°C or lower, still more preferably 90°C or lower.

[0047] The softening point and glass transition temperature of resin (A) can be appropriately adjusted according to the types of raw material components and their usage amounts, as well as production conditions such as reaction temperature, reaction time, and cooling rate, and are determined by the method described in the examples below. When using two or more kinds of resin (A) in combination, it is preferable that the softening point and glass transition temperature of the resin (A) obtained as their mixture are respectively within the above ranges.

[0048] Resin (A) contains a methyl ethyl ketone-insoluble component to maintain the concavo-convex structure of the image. From the viewpoint of improving laminate adhesiveness, when 2 g of resin (A) is dissolved in 95 g of methyl ethyl ketone at 25°C, the content of the methyl ethyl ketone-insoluble component in resin (A) is 1% by mass or more, preferably 2% by mass or more, more preferably 3% by mass or more, and is preferably 40% by mass or less, more preferably 35% by mass or less, still more preferably 33% by mass or less from the viewpoint of the toner having excellent laminate adhesion.

[0049] The binder resin may contain, in addition to resin (A), resins such as amorphous polyester resin, crystalline polyester resin, acrylic resins such as styrene-acrylic copolymer, and polyurethane resin, as long as the effects of the present invention are not impaired. As other amorphous polyester resins of resin (A), there is no particular limitation as long as they contain a polycondensate of an alcohol component and a carboxylic acid component. For example, polyester resins composed of polycondensates and modified polyester resins can be mentioned. Examples of the modified polyester resin include composite resins containing a polyester resin segment and an addition polymerization 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 polycondensates of an alcohol component and a carboxylic acid component are preferred.

[0050] From the viewpoint of providing a toner excellent in hot offset resistance and laminate adhesion, the content of resin (A) in the toner is preferably 40% by mass or more, more preferably 45% by mass or more, still more preferably 50% by mass or more, and preferably 80% by mass or less, more preferably 75% by mass or less, still more preferably 70% by mass or less.

[0051] The toner contains a binder resin containing resin (A) and a colorant, and in addition, may contain other components such as a charge control agent.

[0052] <Colorant> As the colorant, all dyes, pigments, etc. used as colorants for toners can be used. 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. The toner of the present invention can be either a black toner or other color toners.

[0053] From the viewpoint of improving the image density, 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, based on 100 parts by mass of the total amount of the binder resin. Also, from the viewpoint of improving the image density, 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, based on the toner.

[0054] <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 Corp., 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.).

[0055] 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, etc. 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, etc.

[0056] 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.

[0057] <Release agent> The toner preferably does not contain a release agent. When the toner contains a release agent, examples of the release agent include hydrocarbon wax, ester wax, silicone wax, and fatty acid amide wax. The content thereof is less than 1 part by mass, preferably 0.6 part by mass or less, more preferably 0.1 part by mass or less, and 0 part by mass or more, more preferably 0 part by mass, based on 100 parts by mass of the total amount of the binder resin in the toner.

[0058] [Toner manufacturing method] The toner may be obtained by any known method such as a melt-kneading method, an emulsion phase inversion method, a polymerization method, an emulsion aggregation method, etc. However, from the viewpoint of productivity and the like, a production method by the melt-kneading method is preferable. When producing the toner by the melt-kneading method, the production method of the toner includes a step of melt-kneading a binder resin containing the resin (A) 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 a melt-kneaded product can be carried out by a known method. For example, after uniformly mixing raw materials such as a binder resin containing the resin (A), a colorant, and, if necessary, a charge control agent, etc. with a mixer such as a Henschel mixer, it can be melt-kneaded with a closed kneader, a single-screw or twin-screw extruder, an open roll type kneader, etc. to produce a melt-kneaded product. 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 production method of the 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.

[0059] 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 obtaining a toner with excellent image density even at a low adhesion amount, 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.

[0060] [Electrophotographic toner] The electrophotographic toner according to an embodiment of the present invention is a toner containing toner mother particles. Further, the toner preferably contains toner mother particles and an external additive externally added to the toner mother particles. According to the present invention, it is possible to provide a toner excellent in hot offset resistance and laminate adhesion.

[0061] The toner is preferably subjected to an addition treatment on the surface of the toner mother particles using a fluidizing agent or the like 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 preferred. When using an external additive, the addition amount of the external additive is preferably 0.5 parts by mass or more, and preferably 5 parts by mass or less, more preferably 4 parts by mass or less, and still more preferably 3 parts by mass or less with respect to 100 parts by mass of the toner mother particles.

[0062] The toner is used, for example, for developing a latent image formed in an electrophotographic method, an electrostatic recording method, an electrostatic printing method, or the like. The toner can be used as a one-component developer or as a two-component developer mixed with a carrier.

[0063] (Recording medium) The recording medium for printing the toner of the present invention is not particularly limited, and examples include plain paper, high-quality paper, coated printing paper such as art paper and coated paper, Japanese paper, postcard paper, synthetic paper, and the like.

Examples

[0064] Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited by these examples. The physical properties of the resin and the like were measured by the following methods. In the notations such as "alkylene oxide (X)", the numerical value X in the parentheses means the average number of added moles of the alkylene oxide.

[0065] [Measurement method] 〔Softening point of resin〕 Using a flow tester "CFT-500D" (manufactured by Shimadzu Corporation), while heating a 1 g 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 defined as the softening point.

[0066] 〔Glass transition temperature of amorphous resin〕 Using a differential scanning calorimeter "Q-20" (manufactured by TA Instruments Japan Co., Ltd.), 0.01 - 0.02 g of the sample was weighed into an aluminum pan, heated up 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 peak apex was defined as the glass transition temperature.

[0067] 〔Methyl ethyl ketone insoluble content of resin〕 (1) Preparation of sample Using a sieve of JIS Z8801, a sample of powdery amorphous polyester resin (A) that passed through a 22-mesh sieve and did not pass through a 30-mesh sieve was collected. When the sample was in lumps or the like, it was crushed using a commercially available hammer and coffee mill, sieved into a powdery form, and used as the sample. (2) Dissolution of sample 2-1. Approximately 2 g of the above sample was precisely weighed into a glass bottle (manufactured by Kashiwa Yoko Glass Co., Ltd., M-140), and the weight was designated as the mass S (g). Then, 95 g of methyl ethyl ketone was added, and an inner lid and an outer lid were attached to the glass bottle. 2-2. By stirring for 5 hours at a peripheral speed of 200 mm / sec, the sample was mixed with methyl ethyl ketone, and then left standing for 10 hours. (3) Filtration 3-1. A glass filter (opening specification 11G-3) attached to a previously weighed eggplant flask (mass A (g)) was prepared. A rubber stopper capable of reducing pressure was used for the seal of the glass filter. Using a volumetric pipette, 20 mL of the supernatant of the mixture prepared in 3-2.2-2 was aspirated, and using the glass filter prepared in 3-1, the degree of vacuum in the eggplant flask before filtering the supernatant was adjusted to 40 kPa, and vacuum filtration was performed. 3-3. Using a volumetric pipette, 20 mL of unused methyl ethyl ketone was aspirated, and vacuum filtration was performed while co-washing the soluble components adhering to the glass filter. (4) Drying 4-1. Using an evaporator under the following conditions, the methyl ethyl ketone in the above eggplant flask was distilled off. Water bath temperature: 70 °C Rotation speed of eggplant flask: 200 r / min Degree of vacuum in the eggplant flask during removal: 40 - 20 kPa Time: 10 minutes 4-2. After drying at 50 °C and 1 torr for 12 hours, the mass B (g) of the eggplant flask was measured. (5) Calculation of methyl ethyl ketone-insoluble content 5-1. From the difference between the above mass B and mass A, the methyl ethyl ketone-soluble content X (g) dissolved in 20 mL of methyl ethyl ketone was calculated. X = B - A 5-2. The methyl ethyl ketone-soluble content Y (g) dissolved in 95 g of methyl ethyl ketone was calculated assuming the specific gravity of methyl ethyl ketone is 0.805. Y = X × 95 / (20 × 0.805) 5-3. The ratio Z (mass%) of the methyl ethyl ketone-soluble content in the sample was calculated. Z = Y / S × 100 5-4. From the ratio Z (mass%) of the above methyl ethyl ketone-soluble content, the ratio (mass%) of the methyl ethyl ketone-insoluble content was calculated. Methyl ethyl ketone-insoluble content (mass%) = 100 - Z Note that the methyl ethyl ketone-insoluble content (mass%) in the amorphous polyester resin (A) was taken as the average value of the measured values of the results of performing the above three times.

[0068] [Toner Evaluation] [Hot Offset Resistance] The printer "MICROLINE 5400" (manufactured by Oki Electric Industry Co., Ltd.) was modified to be able to take unfixed images, filled with toner, and printed unfixed images of solid images with a size of 2 cm square. 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 external 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 by 5 °C each at a rotational speed of the fixing roll of 150 mm / sec, the fixing process of this unfixed image was performed at each temperature to obtain a fixed image. The obtained fixed images at 100 °C to 200 °C were visually confirmed, and the highest temperature of the fixing roll at which no hot offset was observed was defined as the maximum fixing temperature. The higher the obtained temperature, the better the hot offset resistance.

[0069] 〔Laminating adhesion〕 Toner was mounted in the non-magnetic one-component developing device "MICROLINE 5400" (manufactured by Oki Electric Industry Co., Ltd.), and the toner adhesion amount was adjusted to 0.45 ± 0.03 mg / cm 2 and a solid image of 4.1 cm × 13.0 cm was printed and fixed at a fixing temperature of 130 °C. A laminating film (LZ-A420) was laminated on the obtained solid image using a laminating device (Sek-GTS500, manufactured by Kokuyo Co., Ltd.). Using a peeling tester (Tensilon STB-1225L, manufactured by A&D Co., Ltd.), the leading end of the laminated film was fixed, a force was applied in the 180 °C direction with respect to the paper, and the force applied when peeling at a linear speed of 100 mm / min was measured, and the laminating adhesion was evaluated according to the following evaluation criteria from the average value. (Evaluation criteria) A: 3.0 N or more B: 2.5 N or more and less than 3.0 N C: 2.0 N or more and less than 2.5 N D: 1.5 N or more and less than 2.0 N E: Less than 1.5 N

[0070] 〔Manufacture of amorphous polyester resin (A)〕 Production Example A1 (Resin A-1) The interior 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. 4,804 g of a propylene oxide (2.2) adduct of bisphenol A, 1,912 g of an ethylene oxide (2.2) adduct of bisphenol A, 1,465 g of terephthalic acid, 1,255 g of dodecenyl succinic anhydride, 1,000 g of a modified 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 held at 8 kPa for 1 hour. After that, after returning to atmospheric pressure, it was cooled to 220 °C, 565 g of trimellitic anhydride was added, and the reaction was carried out at 220 °C for 0.5 hr. Then, the pressure inside the flask was reduced, and the reaction was carried out at 20 kPa until the softening point shown in Table 1 was reached to obtain Resin A-1. The physical properties are shown in Table 1.

[0071] Production Examples A2 to A9, and Comparative Production Examples A'1 and A'2 [Resins A-2 to A-9, and Resins A'-1 and A'-2] Resins A-2 to A-9, and Resins A'-1 and A'-2 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.

[0072] In addition, the alkenyl succinic acid and modified silicone used in Production Examples A1 to A9, and Comparative Production Examples A'1 and A'2 are as follows. · DDSA-C: Dodecenyl succinic anhydride having a branched structure in the alkenyl group · DDSA: Linear dodecenyl 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-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-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 = 2,500 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-1001: Modified silicone oil "KF-1001" (silicone having epoxy groups 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.)

[0073]

Table 1

[0074] 〔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 dehydrating tube, a stirrer, and a thermocouple was purged with nitrogen. 3,721 g of a propylene oxide (2.2) adduct of bisphenol A, 3,455 g of an ethylene oxide (2.2) adduct of bisphenol A, 2,824 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 the reaction was carried out at 8 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 100.5 °C, the glass transition temperature was 56.6 °C, and the methyl ethyl ketone insoluble content in Resin B-1 was 0%.

[0075] 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 parts by mass of the positive charge control agent "Bontron N-79" (manufactured by Orient Chemical Industries, Ltd.), and 6 parts by mass of the colorant "Regal 330R" (manufactured by Cabot Corporation, carbon black) were used. If necessary, a release agent "HNP-9" manufactured by Nippon Seiro Co., Ltd. in the amount shown in Table 2 was 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. The temperature of the kneaded product was 160 °C, the supply rate of the kneaded product was 10 kg / h, and the average residence time was about 18 seconds.

[0076] After cooling the kneaded product, it was roughly pulverized to about 1 mm using a hammer mill (manufactured by Hosokawa Micron Corporation). The obtained roughly pulverized product was finely pulverized and classified using a collision plate type jet mill pulverizer IDS-2 type (manufactured by Nippon Pneumatic Mfg. Co., Ltd.) at a supply rate of 4.0 kg / h so that the target volume median diameter (D 50 ) was set to 6.5 μm, and toner mother particles were obtained by adjusting the pulverization pressure.

[0077] To 100 parts by mass of the obtained toner mother particles, 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 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.

[0078]

Table 2

[0079] As shown in Table 2, from the results of the examples and comparative examples, the toner of the present invention was excellent in hot offset resistance and laminate adhesiveness. On the other hand, the toner of Comparative Example 1 containing a large amount of a release agent was inferior in hot offset resistance and laminate adhesiveness. Further, the toner of Comparative Example 2 in which the amorphous polyester resin did not contain methyl ethyl ketone-insoluble matter was more inferior in hot offset resistance and laminate adhesiveness. Furthermore, the toner of Comparative Example 3 in which the amorphous polyester resin did not contain a structure derived from alkenyl succinic acid had sufficient laminate adhesion but was inferior in hot offset resistance.

Claims

1. An electrophotographic toner containing a binder resin, wherein the binder resin contains an amorphous polyester resin (A) which is a reaction product of raw material components including a dicarboxylic acid component having two or more valences, an alcohol component having two or more valences, and a modified silicone, the dicarboxylic acid component contains 5 mol% or more and 35 mol% or less 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 insoluble matter when the amorphous polyester resin (A) is dissolved in methyl ethyl ketone is 1% by mass or more based on the mass of the amorphous polyester resin (A), the content of the release agent is 0 part by mass or more and less than 1 part by mass with respect to 100 parts by mass of the total amount of the binder resin, An electrophotographic toner.

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

4. The electrophotographic toner according to any one of claims 1 to 3, wherein the alkenyl group of the alkenyl succinic acid has a branched structure.

5. The electrophotographic toner according to any one of claims 1 to 4, wherein the softening point of the amorphous polyester resin (A) is 128°C or higher.

6. The electrophotographic toner 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. A method for producing an electrophotographic toner, comprising a step of melt-kneading a binder resin composition containing an amorphous polyester resin (A) which is a reaction product of raw material components including a dicarboxylic acid component having two or more valences, an alcohol component having two or more valences, and a modified silicone to obtain a melt-kneaded product, and a step of pulverizing and classifying the melt-kneaded product to obtain toner mother particles, wherein the dicarboxylic acid component contains 5 mol% or more and 35 mol% or less 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 insoluble matter when the amorphous polyester resin (A) is dissolved in methyl ethyl ketone is 1% by mass or more based on the mass of the amorphous polyester resin (A), The content of the release agent is 0 part by mass or more and less than 1 part by mass with respect to 100 parts by mass of the total amount of the binder resin in the binder resin composition. Method for producing an electrophotographic toner.

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