Polyester resin for toner, toner particle, toner for electrostatic charge image development, and electrostatic charge image developer

Abstract

To provide a polyester resin for toner with which an image excellent in glossiness is obtained without impairing low temperature fixability, electrification performance, and high-temperature resistance.SOLUTION: A polyester resin for toner includes a monobasic acid (a1), a polybasic acid (a2), a polyalcohol (a3), a monoepoxy compound (a4), and a polyepoxy compound (a5) having four or more epoxy groups, as reactive components. The polybasic acid (a2) is formed of an aromatic dicarboxylic acid and an aliphatic dicarboxylic acid, and includes the aliphatic dicarboxylic acid in an amount of 1-15 pts.mass relative to 100 pts.mass of the aromatic dicarboxylic acid. The ratio of the polyepoxy compound (a5) having four or more epoxy groups in the reactive components is within a range of 1.0-5.0 mass% of the total of the (a1)-(a5).SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a polyester resin for a toner, toner particles, a toner for developing an electrostatic image, and an electrostatic image developer. [Background technology]

[0002] Known development methods in electrophotography include, for example, one-component development and two-component development. As electrophotographic toners used in such electrophotography and having excellent low-temperature fixing properties, chargeability, and charge stability, polyester resins produced by combining polybasic acids, polyhydric alcohols, and multiple epoxy compounds with different numbers of epoxy groups are known (Patent Documents 1 to 3). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-242043 [Patent Document 2] Japanese Patent Application Laid-Open No. 2009-265580 [Patent Document 3] International Publication No. 2015 / 045888 Summary of the Invention [Problem to be solved by the invention]

[0004] Recently, the quality of images obtained from cameras has become extremely high, and there is a demand for toners that can contribute to the quality of images obtained by development in addition to the conventionally required properties of low-temperature fixability, chargeability, and high-temperature resistance. However, the toners disclosed in the above Patent Documents 1 to 3 all have the problem that the gloss of the images obtained is insufficient.

[0005] The problem to be solved by the present invention is to provide a polyester resin for a toner that can give an image with excellent gloss without impairing low-temperature fixability, charging performance, and high-temperature resistance. Another problem to be solved by the present invention is to provide toner particles, a toner for developing electrostatic images, and an electrostatic image developer that can provide images with excellent gloss without impairing low-temperature fixability, charging performance, and high-temperature resistance. [Means for solving the problem]

[0006] The present invention relates to the following polyester resin for toner, etc. 1. A polyester resin for a toner, comprising, as reaction components, a monobasic acid (a1), a polybasic acid (a2), a polyhydric alcohol (a3), a monoepoxy compound (a4), and a polyepoxy compound (a5) having four or more epoxy groups, the polybasic acid (a2) comprises an aromatic dicarboxylic acid and an aliphatic dicarboxylic acid, and contains 1 to 15 parts by mass of the aliphatic dicarboxylic acid per 100 parts by mass of the aromatic dicarboxylic acid; A polyester resin for toner, wherein the proportion of the polyepoxy compound (a5) having four or more epoxy groups in the reaction components is in the range of 1.0 to 5.0 mass % of the total of the (a1) to (a5). 2. The polyester resin for toner according to 1, wherein the monobasic acid (a1) is an aromatic monocarboxylic acid. 3. The polyester resin for toner according to 1 or 2, wherein the polyhydric alcohol (a3) ​​is an aliphatic polyol and / or an aromatic diol having a bisphenol skeleton. 4. The polyester resin for toner according to any one of 1 to 3, wherein the monoepoxy compound (a4) is an alkyl glycidyl ester. 5. The polyester resin for toner according to any one of 1 to 4, wherein the polyepoxy compound (a5) having 4 or more epoxy groups is a novolac type epoxy resin having 4 to 10 epoxy groups. 6. The polyester resin for toner according to any one of 1 to 5, wherein the mass ratio of the monobasic acid (a1) to the polybasic acid (a2) is (a1):(a2) in the range of 1:99 to 10:90. 7. A polyester resin for toner according to any one of 1 to 6, wherein the total proportion of the monoepoxy compound (a4) and the polyepoxy compound (a5) having four or more epoxy groups in the reaction components is in the range of 1.0 to 6.0 mass % of the total of (a1) to (a5). 8. A polyester resin for toner according to any one of 1 to 7, wherein the ratio of the monobasic acid (a1) to the total of the monoepoxy compound (a4) and the polyepoxy compound (a5) having four or more epoxy groups in the reaction components [(a1) / (a4+a5) (mass)] is in the range of 40 / 60 to 60 / 40. 9. The polyester resin for toner according to any one of 1 to 8, which has a glass transition temperature in the range of 48 to 58°C. 10. Toner particles containing the polyester resin for toner according to any one of 1 to 9. 11. A toner for developing electrostatic images, comprising toner particles according to 10. 12. An electrostatic image developer comprising the toner for developing electrostatic images according to 11 and a carrier. [Effects of the Invention]

[0007] The present invention can provide a polyester resin for toner that can provide images with excellent gloss without impairing low-temperature fixability, charging performance, and high-temperature resistance. The present invention can provide toner particles, a toner for developing electrostatic images, and an electrostatic image developer that can provide images with excellent gloss without impairing low-temperature fixability, charging performance, and high-temperature resistance. DETAILED DESCRIPTION OF THE INVENTION

[0008] An embodiment of the present invention will be described below. The present invention is not limited to the following embodiment, and can be implemented by making appropriate modifications within the scope that does not impair the effects of the present invention. The compounds in this specification may be derived from fossil resources or biological resources.

[0009] [Polyester resin for toner] The polyester resin for toner of the present invention is a polyester resin for toner having, as reaction components, a monobasic acid (a1), a polybasic acid (a2), a polyhydric alcohol (a3), a monoepoxy compound (a4), and a polyepoxy compound (a5) having four or more epoxy groups. In the present invention, the polybasic acid (a2) comprises an aromatic dicarboxylic acid and an aliphatic dicarboxylic acid, and contains 1 to 15 parts by mass of the aliphatic dicarboxylic acid per 100 parts by mass of the aromatic dicarboxylic acid. Also, in the present invention, the proportion of the polyepoxy compound (a5) having four or more epoxy groups in the reaction components is in the range of 1.0 to 5.0% by mass of the total of (a1) to (a5). Each component will be described below.

[0010] Examples of the monobasic acid (a1) include aliphatic monocarboxylic acids and aromatic monocarboxylic acids.

[0011] The aliphatic monocarboxylic acid is preferably an aliphatic monocarboxylic acid having 1 to 18 carbon atoms, and more preferably one or more selected from acetic acid, propionic acid, butyric acid, octylic acid, lauric acid, stearic acid, oleic acid, and palmitic acid. The aliphatic monocarboxylic acid may be a saturated aliphatic monocarboxylic acid or an unsaturated aliphatic monocarboxylic acid.

[0012] The aromatic monocarboxylic acid is preferably an aromatic monocarboxylic acid having 6 to 11 carbon atoms, and more preferably one or more selected from benzoic acid, benzoic acid substituted with an alkyl group having 1 to 6 carbon atoms (e.g., t-butylbenzoic acid), hexahydrobenzoic acid, and phenylacetic acid. The benzoic acid substituted with an alkyl group having 1 to 6 carbon atoms is preferably substituted with an alkyl group at the p-position and / or o-position, more preferably benzoic acid substituted with an alkyl group at the p-position, and even more preferably para-tert-butylbenzoic acid.

[0013] The monobasic acid (a1) preferably includes an aromatic monocarboxylic acid, more preferably includes an aromatic monocarboxylic acid having 6 to 11 carbon atoms, and even more preferably is benzoic acid and / or benzoic acid substituted with an alkyl group having 1 to 6 carbon atoms.

[0014] The monobasic acid (a1) may be used alone or in combination of two or more kinds.

[0015] The proportion of the monobasic acid (a1) in the reaction components (a1) to (a5) is, for example, in the range of 0.5 to 5 mass %, and more preferably in the range of 1 to 5 mass %.

[0016] The polybasic acid (a2) comprises an aromatic dicarboxylic acid and an aliphatic dicarboxylic acid. The aromatic dicarboxylic acid may be, for example, an aromatic dicarboxylic acid having 8 to 18 carbon atoms, and specific examples of the aromatic dicarboxylic acid include phenylmalonic acid, phenylsuccinic acid, phthalic acid, isophthalic acid, terephthalic acid, β-phenylglutaric acid, α-phenyladipic acid, β-phenyladipic acid, biphenyl-2,2'-dicarboxylic acid, biphenyl-4,4'-dicarboxylic acid, and naphthalenedicarboxylic acid. The aliphatic dicarboxylic acid may be, for example, an aliphatic dicarboxylic acid having 2 to 18 carbon atoms. Specific examples of the aliphatic dicarboxylic acid include succinic acid, glutaric acid, adipic acid, maleic acid, pimelic acid, suberic acid, sebacic acid, azelaic acid, undecanedioic acid, dodecanedioic acid, tridecanedioic acid, tetradecanedioic acid, pentadecanedioic acid, hexadecanedioic acid, heptadecanedioic acid, octadecanedioic acid, and cyclohexanedicarboxylic acid.

[0017] The aromatic dicarboxylic acid may be used alone or in combination of two or more kinds. Similarly, the aliphatic dicarboxylic acid may be used alone or in combination of two or more kinds.

[0018] The aromatic dicarboxylic acid and the aliphatic dicarboxylic acid may each be an acid anhydride of the dicarboxylic acid or an alkyl ester of the dicarboxylic acid.

[0019] The polybasic acid (a2) contains 1 to 15 parts by mass of the aliphatic dicarboxylic acid per 100 parts by mass of the aromatic dicarboxylic acid, and preferably contains 1 to 12 parts by mass of the aliphatic dicarboxylic acid per 100 parts by mass of the aromatic dicarboxylic acid. By adjusting the ratio of the aromatic dicarboxylic acid and the aliphatic dicarboxylic acid to be used within this range, the glass transition temperature of the polyester can be adjusted.

[0020] The mass ratio of the monobasic acid (a1) to the polybasic acid (a2) is preferably (a1):(a2)=1:99 to 10:90, more preferably (a1):(a2)=2:98 to 5:95.

[0021] The proportion of the polybasic acid (a2) in the reaction components (a1) to (a5) is, for example, in the range of 30 to 70 mass %, preferably in the range of 35 to 70 mass %, and more preferably in the range of 40 to 60 mass %.

[0022] The polyhydric alcohol (a3) ​​is a compound having two or more hydroxyl groups in one molecule, and for example, an aliphatic polyol or an aromatic polyol can be used.

[0023] Examples of the aliphatic polyol include ethylene glycol, diethylene glycol, triethylene glycol, propylene glycol, dipropylene glycol, tripropylene glycol, butanediol, pentanediol, neopentyl glycol, hexanediol, 2-ethyl-4-butylhexanediol, butylethylpropanediol, 2,4-diethyl-3,5-pentanediol, polyethylene glycol, polypropylene glycol, ethylene oxide-propylene oxide random copolymer diol, ethylene oxide-propylene oxide block copolymer diol, ethylene oxide-tetrahydrofuran copolymer diol, polycaprolactone diol, glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, dipentaerythritol, and 2-methylpropanetriol.

[0024] The aliphatic polyol may have an alicyclic structure, and examples of the aliphatic polyol having an alicyclic structure include 1,4-cyclohexanedimethanol and hydrogenated bisphenol A.

[0025] The aliphatic polyol is preferably an aliphatic polyol having 1 to 12 carbon atoms, and more preferably an aliphatic polyol having 1 to 6 carbon atoms.

[0026] Examples of the aromatic polyol include aromatic polyols having a bisphenol skeleton, such as bisphenols (e.g., bisphenol A, bisphenol F, etc.) and bisphenol alkylene oxide adducts (e.g., ethylene oxide adduct of bisphenol A, propylene oxide adduct of bisphenol A, etc.). When the aromatic polyol is a bisphenol alkylene oxide adduct, the alkylene oxide substituting the bisphenol is preferably an alkylene oxide having 1 to 6 carbon atoms.

[0027] The aromatic polyol is preferably an aromatic diol having a bisphenol skeleton with 13 to 32 carbon atoms.

[0028] The polyhydric alcohol (a3) ​​preferably includes an aliphatic polyol and / or an aromatic polyol having a bisphenol skeleton, and more preferably an aliphatic polyol and / or an aromatic polyol having a bisphenol skeleton.

[0029] The polyhydric alcohol (a3) ​​may be used alone or in combination of two or more kinds.

[0030] The proportion of the polyhydric alcohol (a3) ​​in the reaction components (a1) to (a5) is, for example, in the range of 20 to 65 mass %, preferably in the range of 20 to 60 mass %, and more preferably in the range of 25 to 60 mass %.

[0031] Preferred examples of the monoepoxy compound (a4) include phenyl glycidyl ether, alkylphenyl glycidyl ether, alkyl glycidyl ether, alkyl glycidyl ester, glycidyl ether of an alkylphenol alkylene oxide adduct, α-olefin oxide, and monoepoxy fatty acid alkyl ester.

[0032] Specific examples of the alkylphenyl glycidyl ether include cresyl glycidyl ether, butyl glycidyl ether, and nonyl glycidyl ether.

[0033] Specific examples of the alkyl glycidyl ether include butyl glycidyl ether and 2-ethylhexyl glycidyl ether.

[0034] Examples of the alkyl glycidyl ester include compounds represented by the following general formula (a4-1).

[0035] [ka] (In the general formula (a4-1), R 1 is an alkyl group having 1 to 25 carbon atoms, preferably an alkyl group having 6 to 15 carbon atoms, L 1 is an alkylene group having 1 to 6 carbon atoms, and preferably an alkylene group having 1 to 3 carbon atoms.

[0036] Examples of the glycidyl ether of an alkylphenol alkylene oxide adduct include glycidyl ethers of compounds in which an alkylene oxide having 1 to 6 carbon atoms, such as ethylene oxide or propylene oxide, is added to a phenol substituted with an alkyl group having 1 to 6 carbon atoms, such as butylphenol.

[0037] Specific examples of the glycidyl ether of the alkylphenol alkylene oxide adduct include glycidyl ether of ethylene glycol monophenyl ether, glycidyl ether of polyethylene glycol monophenyl ether, glycidyl ether of propylene glycol monophenyl ether, glycidyl ether of polypropylene glycol monophenyl ether, glycidyl ether of propylene glycol mono(pt-butyl)phenyl ether, and glycidyl ether of ethylene glycol monononylphenyl ether.

[0038] Examples of the α-olefin oxide include compounds obtained by oxidizing olefins, such as Alpha Olefin Oxide-168 (a product of Adeka Argas Chemical Co., Ltd.) and Alpha Olefin Oxide-124 (a product of Adeka Argas Chemical Co., Ltd.).

[0039] The monoepoxy fatty acid alkyl ester is, for example, a compound in which an unsaturated group of an alcohol ester of an unsaturated fatty acid is epoxidized, and preferably a compound in which an unsaturated group is epoxidized, which is an ester of an unsaturated aliphatic monocarboxylic acid having 6 to 24 carbon atoms and an alcohol having 1 to 6 carbon atoms. The degree of unsaturation of the unsaturated fatty acid is not particularly limited, but is in the range of 1 to 3, for example.

[0040] Specific examples of the unsaturated fatty acids include sorbic acid, oleic acid, linoleic acid, linolenic acid, eleostearic acid, ricinoleic acid, tung oil fatty acid, linseed oil fatty acid, dehydrated castor oil fatty acid, castor oil fatty acid, tall oil fatty acid, cottonseed oil fatty acid, soybean oil fatty acid, olive oil fatty acid, safflower oil fatty acid, and rice bran oil fatty acid. Tung oil fatty acids, linseed oil fatty acids, dehydrated castor oil fatty acids, castor oil fatty acids, tall oil fatty acids, cottonseed oil fatty acids, soybean oil fatty acids, olive oil fatty acids, safflower oil fatty acids, and rice bran oil fatty acids are mixtures of unsaturated aliphatic monocarboxylic acids having 10 to 22 carbon atoms.

[0041] Specific examples of the monoepoxy fatty acid alkyl ester include epoxidized butyl oleate, a compound represented by CH3(CH2)7CH-CHOCH-(CH2)6COOC4H6 (CHOCH represents an epoxy ring), and epoxidized octyl oleate.

[0042] The monoepoxy compound (a4) preferably comprises an alkyl glycidyl ester, more preferably an alkyl glycidyl ester.

[0043] The monoepoxy compound (a4) may be used alone or in combination of two or more kinds.

[0044] The proportion of the monoepoxy compound (a4) in the reaction components (a1) to (a5) is, for example, in the range of 0.01 to 3.0 mass %, and preferably in the range of 0.01 to 1.0 mass %.

[0045] The polyepoxy compound (a5) having four or more epoxy groups is a compound having four or more epoxy groups in one molecule, and is used mainly for the purpose of imparting gloss to the resulting image by adjusting the crosslink density in the polyester resin to an appropriate range.

[0046] Examples of the polyepoxy compound (a5) include novolac type epoxy resins, polymers containing as at least a reactive component a vinyl compound having an epoxy group, epoxidized resorcinol-acetone condensates, and partially epoxidized polybutadienes.

[0047] The polyepoxy compound (a5) preferably comprises a novolac type epoxy resin, and more preferably is a novolac type epoxy resin.

[0048] When the polyepoxy compound (a5) is a novolac type epoxy resin, examples of the novolac type epoxy resin include cresol novolac type epoxy resin, phenol novolac type epoxy resin, bisphenol A novolac type epoxy resin, bisphenol A alkylene oxide adduct novolac type epoxy resin, bisphenol F alkylene oxide adduct novolac type epoxy resin, naphthalene novolac type epoxy resin, dicyclopentadiene novolac type epoxy resin, and the like, and preferably at least one selected from cresol novolac type epoxy resin, bisphenol A novolac type epoxy resin, and phenol novolac type epoxy resin.

[0049] When the polyepoxy compound (a5) is a novolac epoxy resin, the novolac epoxy resin is preferably a novolac epoxy resin having 4 to 15 epoxy groups in one molecule. The number of epoxy groups in a novolac epoxy resin can be confirmed by a known method, and may be evaluated in accordance with, for example, JIS K726:2001.

[0050] The polyepoxy compound (a5) may be used alone or in combination of two or more kinds. When two or more types of polyepoxy compounds (a5) are used, the number average of epoxy groups in the mixture of two or more types of polyepoxy compounds (a5) may be 4 or more.

[0051] The proportion of the polyepoxy compound (a5) in the reaction components (a1) to (a5) is in the range of 1.0 to 5.0 mass %, and preferably in the range of 1.0 to 4.0 mass %. By setting the proportion of the polyepoxy compound (a5) within the above range, the gloss of the obtained image can be increased.

[0052] The total proportion of the monoepoxy compound (a4) and the polyepoxy compound (a5) in the reaction components is preferably in the range of 0.5 to 10 mass% of the total of the reaction components (a1) to (a5), more preferably in the range of 1.0 to 6.0 mass% of the total of the reaction components (a1) to (a5), and even more preferably in the range of 1.0 to 5.0 mass% of the total of the reaction components (a1) to (a5).

[0053] The ratio of the monobasic acid (a1) to the total of the monoepoxy compound (a4) and the polyepoxy compound (a5) in the reaction components [(a1) / (a4+a5) (mass)] is preferably in the range of 40 / 60 to 60 / 40.

[0054] The polyester resin of the present invention is a polyester resin having a monobasic acid (a1), a polybasic acid (a2), a polyhydric alcohol (a3), a monoepoxy compound (a4), and a polyepoxy compound (a5) as reactive components, but other components may also be used as reactive components. As other components, monoalcohols (a6) such as stearyl alcohol can be used.

[0055] The reactive components of the polyester resin of the present invention preferably consist essentially of a monobasic acid (a1), a polybasic acid (a2), a polyhydric alcohol (a3), a monoepoxy compound (a4) and a polyepoxy compound (a5). Here, "substantially consisting of" means that the total of the monobasic acid (a1), polybasic acid (a2), polyhydric alcohol (a3), monoepoxy compound (a4) and polyepoxy compound (a5) accounts for 90% by mass or more, 95% by mass or more, or 100% by mass of the reaction components.

[0056] The polyester resin of the present invention preferably has a mass ratio (gel fraction) of components insoluble in tetrahydrofuran at 25° C. in the range of 10 to 70 mass %, more preferably 20 to 60 mass %. The gel fraction is confirmed by the method described in the examples.

[0057] The polyester resin of the present invention preferably has a glass transition temperature (Tg) in the range of 47° C. or higher and lower than 60° C., more preferably in the range of 48 to 58° C., and even more preferably in the range of 48 to 56° C. When the glass transition temperature (Tg) is in this range, excellent low-temperature fixability can be achieved. The glass transition temperature of the polyester resin is confirmed by the method described in the examples.

[0058] The polyester resin of the present invention can be produced by a known method, for example, by a reaction such as an ester exchange reaction, an atmospheric pressure dehydration reaction, a reduced pressure or vacuum dehydration reaction, a solution polycondensation method, or a solid-phase polycondensation reaction in the presence of an esterification catalyst (such as a tin compound, a titanium compound, or a zirconium compound) or in the presence of a transesterification catalyst (such as a lead compound, a tin compound, a zinc compound, or a titanium compound). The polyesterification reaction can be monitored by measuring the acid value, hydroxyl value, viscosity, or softening point.

[0059] The polyester resin of the present invention is preferably produced by a method (so-called batch charging method) in which the reaction components, i.e., a monobasic acid (a1), a polybasic acid (a2), a polyhydric alcohol (a3), a monoepoxy compound (a4), and a polyepoxy compound (a5), are dissolved and mixed, and then an esterification catalyst is added, followed by heating to allow the reaction to proceed.

[0060] [Electrostatic image developing toner] The toner for developing electrostatic images of the present invention contains the polyester resin of the present invention. The toner for developing electrostatic images of the present invention (hereinafter, sometimes simply referred to as "the toner of the present invention") contains the polyester resin of the present invention as a binder resin, and therefore can be a toner that can provide images with excellent gloss without impairing low-temperature fixability, charging performance, and high-temperature resistance.

[0061] The content of the polyester resin of the present invention in the toner of the present invention is not particularly limited, but is preferably 10 to 95 mass % of the total mass of the solid content of the toner, more preferably 25 to 90 mass %, and even more preferably 45 to 85 mass %. When the content of the polyester resin of the present invention is within the above range, excellent low-temperature fixability and charging performance can be obtained.

[0062] (Other binder resins) The toner of the present invention is only required to contain the polyester resin of the present invention, and may contain binder resins other than the polyester resin of the present invention as long as the effects of the present invention are not impaired. The other binder resins are not particularly limited and include, for example, polystyrene, styrene-butadiene polymers, styrene-acrylic polymers, polyester resins other than the polyester resin of the present invention, etc. These other binder resins may be further modified with urethane, urea, epoxy, etc.

[0063] (coloring agent) The toner of the present invention preferably contains a colorant for the purpose of coloring the resulting image. The colorant may be appropriately selected from known colorants depending on the purpose, and pigments and dyes of various colors may be used.

[0064] Examples of the pigments include black pigments such as carbon black, copper oxide, manganese dioxide, aniline black, activated carbon, non-magnetic ferrite, and magnetite; yellow pigments such as yellow lead, zinc yellow, yellow iron oxide, cadmium yellow, chrome yellow, Hansa Yellow, Hansa Yellow 10G, benzidine yellow G, benzidine yellow GR, threne yellow, quinoline yellow, and permanent yellow NCG; orange pigments such as red yellow lead, molybdenum orange, permanent orange GTR, pyrazolone orange, vulcan orange, benzidine orange G, induthrene brilliant orange RK, and induthrene brilliant orange GK; red iron oxide, cadmium red, red lead, mercury sulfide, watching red, permanent red 4R, lithol red, brilliant carmine 3B, and brilliant orange NCG. Examples of pigments that can be used include red pigments such as benzocathol 6B, pyrazolone red, rhodamine lake B, lake red C, rose bengal, eosin red, and alizarin lake; blue pigments such as iron blue, cobalt blue, alkali blue lake, Victoria blue lake, fast sky blue, indanthrene blue BC, ultramarine blue, phthalocyanine blue, and phthalocyanine green; purple pigments such as manganese purple, fast violet B, and methyl violet lake; green pigments such as chromium oxide, chrome green, pigment green B, malachite green lake, and fanal yellow green G; white pigments such as zinc oxide, titanium oxide, antimony white, and zinc sulfide; and extender pigments such as baryte powder, barium carbonate, clay, silica, white carbon, talc, and alumina white. These pigments may be used alone or in combination of two or more.

[0065] Examples of the dye include various dyes such as basic dyes, acid dyes, disperse dyes, and direct dyes. Specific examples of the dye include nigrosine, methylene blue, rose bengal, and quinoline yellow. These dyes may be used alone or in combination of two or more.

[0066] The colorant may be used, for example, in the form of a dispersion of colorant particles. Examples of methods for preparing a dispersion of colorant particles include using a media-type disperser such as a rotary shear homogenizer, a ball mill, a sand mill, or an attritor; or a high-pressure counter-collision disperser to prepare a dispersion of colorant particles, or adding a polar surfactant and then using a homogenizer to prepare a dispersion of colorant particles.

[0067] The content of the colorant in the toner of the present invention is preferably 0.1 to 40% by mass, more preferably 0.5 to 20% by mass, of the total mass of the solid content of the toner in order to ensure color development during fixing. However, when a magnetic material is used as the black colorant, the content of the black colorant is preferably 12 to 48% by mass, more preferably 15 to 40% by mass, of the total mass of the solid content of the toner.

[0068] By appropriately selecting the type of colorant, toners of various colors such as yellow toner, magenta toner, cyan toner, black toner, etc. can be obtained.

[0069] (mold release agent) The toner of the present invention preferably contains a release agent for the purpose of improving releasability. Examples of the release agent include low molecular weight polyolefins such as polyethylene, polypropylene, and polybutene; silicones that soften when heated; fatty acid amides such as oleic acid amide, erucic acid amide, ricinoleic acid amide, and stearic acid amide; vegetable waxes such as carnauba wax, rice wax, candelilla wax, Japan wax, and jojoba oil; animal waxes such as beeswax; mineral and petroleum waxes such as montan wax, ozokerite, ceresin, paraffin wax, microcrystalline wax, and Fischer-Tropsch wax; and ester waxes such as fatty acid esters, montan acid esters, and carboxylic acid esters. These release agents may be used alone or in combination of two or more.

[0070] The amount of the release agent added is preferably 0.5 to 50% by mass, more preferably 1 to 30% by mass, and even more preferably 5 to 15% by mass, based on the total amount of toner particles.

[0071] The toner of the present invention may contain other components in addition to the binder resin, colorant, and release agent, as long as the effects of the present invention are not impaired. Examples of such other components include known additives such as inorganic particles, organic particles, charge control agents, and internal additives.

[0072] The inorganic particles are generally used for the purpose of improving the fluidity of the toner. Examples of the inorganic particles include particles of silica, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, silica sand, clay, mica, wollastonite, diatomaceous earth, cerium chloride, red iron oxide, chromium oxide, cerium oxide, antimony trioxide, magnesium oxide, zirconium oxide, silicon carbide, silicon nitride, etc. Among these, silica particles are preferred, and hydrophobically treated silica particles are particularly preferred.

[0073] The organic particles are used for the purpose of improving cleaning properties, transfer properties, chargeability, and the like. Examples of the organic particles include particles of polystyrene, polymethyl methacrylate, polyvinylidene fluoride, polystyrene-acrylic copolymer, and the like.

[0074] Examples of the charge control agent include metal salicylate, metal-containing azo compounds, nigrosine, and quaternary ammonium salts.

[0075] Examples of the internal additive include magnetic materials such as metals such as ferrite, magnetite, reduced iron, cobalt, nickel, and manganese, alloys, and compounds containing these metals.

[0076] The toner of the present invention can be produced by known methods, such as kneading and pulverization, emulsion aggregation, suspension polymerization, and dissolution suspension, with the emulsion aggregation method being preferred. The kneading and pulverization method is a method for producing toner base particles by kneading a binder resin with a colorant, a release agent, a charge control agent, etc., and pulverizing and classifying the resulting kneaded product. The resulting toner base particles may be further subjected to mechanical impact force or thermal energy to change their shape. The emulsion aggregation method is a method of producing toner base particles by mixing a dispersion liquid in which a binder resin is emulsified and dispersed with a dispersion liquid of a colorant, a release agent, a charge control agent, etc., and aggregating and heat-fusing the mixture. The suspension polymerization method is a method for producing toner base particles by suspending a polymerizable monomer for obtaining a binder resin and solutions of a colorant, a release agent, a charge control agent, etc. in an aqueous solvent. The dissolution suspension method is a method in which a binder resin and solutions of a colorant, a release agent, a charge control agent, etc. are suspended in an aqueous solvent to form toner base particles.

[0077] The toner base particles obtained by the above method may be used as a core, and aggregated particles may be attached to the surface of the core, followed by heating and fusing to form a toner having a core-shell structure.

[0078] [Electrostatic image developer] The toner of the present invention is suitably used as an electrostatic image developer. The electrostatic image developer of the present invention may contain the toner of the present invention. For example, when the toner of the present invention is used alone as the electrostatic image developer, the electrostatic image developer of the present invention becomes a one-component electrostatic image developer, and when the toner of the present invention is used in combination with a known carrier as the electrostatic image developer, the electrostatic image developer becomes a two-component electrostatic image developer.

[0079] Examples of the core material of the carrier include magnetic metals such as iron, steel, nickel, and cobalt; alloys of the magnetic metals with manganese, chromium, and rare earth elements; and magnetic oxides such as ferrite and magnetite.

[0080] The surface of the core material of the carrier may be coated with a resin. Examples of the resin for coating the surface of the core material include polyolefin resins such as polyethylene and polypropylene; polystyrene, acrylic resin, polyacrylonitrile, polyvinyl acetate, polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride, polyvinyl carbazole, polyvinyl ether, and polyvinyl ketone; polyvinylidene resins; vinyl chloride-vinyl acetate copolymers; styrene-acrylic acid copolymers; straight silicone resins having organosiloxane bonds or modified products thereof; fluorine-based resins such as polytetrafluoroethylene, polyvinyl fluoride, polyvinylidene fluoride, and polychlorotrifluoroethylene; silicone resins; polyesters; polyurethanes; polycarbonates; phenolic resins; amino resins such as urea-formaldehyde resins, melamine resins, benzoguanamine resins, urea resins, and polyamide resins; and epoxy resins. These resins may be used alone or in combination of two or more.

[0081] When the carrier is a carrier made of a core material coated with a resin, it is preferable that resin particles and / or conductive particles are dispersed in the resin coating layer. The resin particles include thermoplastic resin particles and thermosetting resin particles, and the resin particles may be used alone or in combination of two or more kinds. Examples of the conductive particles include metal particles such as gold, silver, and copper particles, carbon black particles, and particles whose surfaces are covered with carbon black or metal, such as titanium oxide, zinc oxide, barium sulfate, aluminum borate, and potassium titanate. These conductive particles may be used alone or in combination of two or more.

[0082] The toner or electrostatic image developer of the present invention is used in a state of being housed in, for example, a cartridge. By housing the toner or electrostatic image developer of the present invention in a cartridge, the cartridge becomes detachable from an image forming apparatus, and it is possible to easily supply the toner or electrostatic image developer to the image forming apparatus. [Example]

[0083] The present invention will be specifically described below with reference to examples and comparative examples. The present invention is not limited to the following examples.

[0084] (Synthesis Examples 1-3 and Comparative Synthesis Examples 1-6: Preparation of Polyester Resins) A four-necked 3-L stainless steel flask equipped with a stirrer, a nitrogen gas inlet, and a thermometer was charged with the reaction components shown in Tables 1 and 2, and 0.8 parts by mass of titanium tetraisopropoxide was also added as a catalyst. The reaction was carried out for 3 hours at 240°C under a nitrogen stream while removing the water produced, and then the temperature was raised to 220°C and the pressure was reduced to 5 kPa to obtain polyester resins A-1 to A-3 and A'-1 to A'-6, respectively.

[0085] The polyester obtained was evaluated as follows, and the results are shown in Tables 1 and 2.

[0086] (Acid value and hydroxyl value) The acid value and hydroxyl value of the resin were measured in accordance with JIS K0070-1992 (neutralization titration method).

[0087] (Number average molecular weight and weight average molecular weight) The number average molecular weight (Mn) and weight average molecular weight (Mw) of the resin were evaluated by gel permeation chromatography (GPC) under the following conditions. Measuring device: Tosoh Corporation HLC-8120GPC Column: TSK-GUARDCOLUMN HXL-H manufactured by Tosoh Corporation + Tosoh TSK-GEL G5000HXL + Tosoh TSK-GEL G4000HXL + Tosoh TSK-GEL G3000HXL + Tosoh TSK-GEL G2000HXL Detector: RI (differential refractometer) Data processing: Tosoh Corporation Multistation GPC-8020modelII Column temperature: 40℃ Solvent: tetrahydrofuran Flow rate: 1.0ml / min Standard: Monodisperse polystyrene Sample: 100 μl of tetrahydrofuran solution containing 0.5% by mass of resin solids filtered through a microfilter

[0088] (Softening point (T1 / 2)) The softening point (T1 / 2) of the resin was evaluated under the following conditions based on the above. The softening point (T1 / 2) refers to the temperature at which the plunger (piston) of the flow tester reaches the midpoint in the process from the start of outflow to the end of outflow. Measurement device: High-performance flow tester (Shimadzu Corporation "CFT-500D") Measurement conditions: temperature rise rate 6°C / min, nozzle 1.0mmΦ x 10mm, load 10kgf, sample amount 1.5g

[0089] (glass transition temperature) The glass transition temperature of the resin was determined by differential scanning calorimetry (DSC) under the following conditions. Measuring device: Seiko Instruments Inc. DSC-220C Data processing: EXSTAR6000 PC station Measurement conditions: (1) Temperature increase from 20°C to 150°C (10°C / min) (2) Hold at 150°C for 10 minutes (3) Decrease temperature from 150°C to 0°C (10°C / min) (4) Keep at 0°C for 10 minutes (5) Heat from 0°C to 150°C (10°C / min) Analysis: In (5), the glass transition point was determined as the intersection of an extension of the low-temperature baseline and a tangent drawn at the point where the gradient of the curve of the step-like change in the glass transition is maximum.

[0090] (gel fraction) 1.5 g of resin was immersed in tetrahydrofuran at room temperature (25°C) and removed after 24 hours. The removed resin insoluble matter was dried at 70°C for 1 hour and reweighed, and the gel fraction was calculated as (mass of resin insoluble matter after immersion) / (mass of resin before immersion)×100.

[0091] [Table 1]

[0092] [Table 2]

[0093] In Tables 1 and 2, the numerical values ​​of each component are in parts by mass.

[0094] (Production and Evaluation of Toners in Examples 1-3 and Comparative Examples 1-6) Ninety parts by weight of the polyester resin shown in Table 3, 5 parts by weight of carbon black MA-11 (manufactured by Mitsubishi Chemical Corporation), 1 part by weight of a chromium (III) compound ("Bontron S34" manufactured by Orient Chemical Industries Co., Ltd.) as a charge control agent, and 4 parts by weight of carnauba wax were mixed in a Henschel mixer to prepare a polyester resin composition. The polyester resin composition was kneaded in a twin-screw kneader, and the resulting kneaded mixture was finely pulverized and classified using a jet mill / classifier ("AFG10 / ATP50" manufactured by Hosokawa Micron Corporation). The classified toner base particles and 1 part by weight of silica ("R972" manufactured by Nippon Aerosil Co., Ltd.) were mixed in a Henschel mixer and then sieved to obtain a mixture. Five parts of the resulting mixture and 95 parts of a carrier (silicon resin-coated ferrite carrier) were mixed and stirred to prepare toners T-1 to T-3 and toners T'-1 to T-6. The toner thus obtained was subjected to the following evaluations, and the results are shown in Table 3.

[0095] (low temperature fixability) The toner was loaded into a copier, and solid printing was performed with the heat roll temperature set to 120°C to 140°C in 5°C increments. A fastness test was performed on the solid printed area, and the image density before and after the test was measured with a Macbeth densitometer (RD-918). The temperature at which the ratio of the density value after peeling to the value before the test was expressed as a percentage and reached 80% or higher was defined as the fixing start temperature. The lower this temperature, the better the low-temperature fixing ability. The evaluation criteria for the low temperature fixability of the toner were as follows: The fastness test was carried out using a Gakushin type friction fastness tester (load: 200 g, rubbing operation: 5 strokes). ◎: When the fixing start temperature is less than 120℃ ○: When the fixing start temperature is 120℃ or higher and lower than 125℃ △: When the fixing start temperature is 125℃ or higher and less than 130℃ ×: When the fixing start temperature is 130°C or higher

[0096] (High temperature offset resistance) Under the conditions of the heat roller fixing machine described below, when the set temperature of the heat roll was changed in 5°C increments from 160°C to 210°C, the solid printed area was offset again onto the same paper, and the lowest temperature at which it could be visually confirmed was displayed. Roll material: Upper: polytetrafluoroethylene, lower: silicone Upper roll load: 7 kg / 350 mm Nip width: 4mm Paper threading speed: 90mm / sec

[0097] The offset start temperature was evaluated according to the following criteria. A higher offset start temperature indicates better offset resistance. Even if offset did not occur at high temperatures, if the resin itself acted as a wax and the fixation to the printing medium was poor, it was evaluated as "X." ◎: When the offset start temperature is 230℃ or higher ○: When the offset start temperature is 215℃ or higher and less than 230℃ △: When the offset start temperature is 190℃ or higher and less than 215℃ ×: When the offset start temperature is less than 190°C

[0098] (Charge amount and charge stability) Using a suction blow-off type charge amount measuring device (210HS-2A, manufactured by Trek Japan Co., Ltd.), a mixture of 1.5 g of toner and 48.5 g of ferrite carrier (MF-1008, manufactured by Nippon Iron Powder Co., Ltd.) was mixed in a 50 ml plastic container with a Turbula Shaker Mixer for 1 minute, 10 minutes, 30 minutes, and 60 minutes, and the charge amount of each resulting mixture was measured using the charge amount measuring device. The average value of the measured charge amounts was taken as the charge amount of the toner. The evaluation criteria for charge amount were as follows: ◎ :-50μC / g or more ○: -45μC / g or more and less than -50μC / g △: -40μC / g or more and less than -45μC / g ×: -35μC / g or more and less than -40μC / g ××: Less than -35μC / g Furthermore, the difference between the maximum and minimum charge amounts of the mixtures mixed for 10, 30, and 60 minutes was determined, and this value was used to evaluate the charge stability. The smaller this value, the better the charge stability. The evaluation criteria for charge stability were as follows: ◎: The difference between the maximum and minimum charge amounts is less than -3 μC / g ○: The difference between the maximum and minimum charge amounts is -3 μC / g or more and less than -6 μC / g △: The difference between the maximum and minimum charge amounts is between -6 μC / g and -9 μC / g ×: The difference between the maximum and minimum charge amounts is -9 μC / g or more

[0099] (glossy) Using the same method as described above for low-temperature fixability, solid printing was performed by varying the set temperature of the heat roll in 5°C increments from 100°C to 210°C. White cardboard was placed underneath the solid print, and the gloss was measured at an incident angle of 60° and a reflection angle of 60° using a gloss meter Micro-Tri-Gloss (manufactured by BYK), and gloss measurements were performed every 5°C from a temperature above the fixing start temperature to the offset start temperature. The highest gloss within this range was defined as the maximum gloss, and was evaluated according to the following criteria. ○: 13% or more △: 9% or more and less than 13% ×: Less than 9%

[0100] [Table 3]

[0101] It can be seen that the gloss of the image is impaired in Comparative Examples 1, 3, and 6 due to the excessive amount of polyepoxy compound. It can be seen that the high temperature resistance is impaired in Comparative Example 2 due to the excessive amount of aliphatic dicarboxylic acid, which is a polybasic acid. It can be seen that the low temperature fixability is impaired in Comparative Examples 4 and 5 due to the absence of aliphatic dicarboxylic acid, which is a polybasic acid.

Claims

1. A polyester resin for a toner, comprising a monobasic acid (a1), a polybasic acid (a2), a polyhydric alcohol (a3), a monoepoxy compound (a4), and a polyepoxy compound (a5) having four or more epoxy groups as reaction components, the polybasic acid (a2) comprises an aromatic dicarboxylic acid and an aliphatic dicarboxylic acid, and contains 1 to 15 parts by mass of the aliphatic dicarboxylic acid per 100 parts by mass of the aromatic dicarboxylic acid; A polyester resin for a toner, wherein the proportion of the polyepoxy compound (a5) having four or more epoxy groups in the reaction components is in the range of 1.0 to 5.0 mass % of the total of the (a1) to (a5).

2. 2. The polyester resin for toner according to claim 1, wherein the monobasic acid (a1) is an aromatic monocarboxylic acid.

3. 2. The polyester resin for toner according to claim 1, wherein the polyhydric alcohol (a3) ​​is an aliphatic polyol and / or an aromatic diol having a bisphenol skeleton.

4. 2. The polyester resin for toner according to claim 1, wherein the monoepoxy compound (a4) is an alkyl glycidyl ester.

5. 2. The polyester resin for toner according to claim 1, wherein the polyepoxy compound (a5) having four or more epoxy groups is a novolac type epoxy resin having 4 to 10 epoxy groups.

6. 2. The polyester resin for toner according to claim 1, wherein the mass ratio of the monobasic acid (a1) to the polybasic acid (a2) is (a1):(a2) in the range of 1:99 to 10:

90.

7. 2. The polyester resin for toner according to claim 1, wherein the total proportion of the monoepoxy compound (a4) and the polyepoxy compound (a5) having four or more epoxy groups in the reaction components is in the range of 1.0 to 6.0 mass % of the total of (a1) to (a5).

8. 2. The polyester resin for toner according to claim 1, wherein a ratio of the monobasic acid (a1) to the total of the monoepoxy compound (a4) and the polyepoxy compound (a5) having four or more epoxy groups in the reaction components [(a1) / (a4+a5) (mass)] is in the range of 40 / 60 to 60 / 40.

9. 2. The polyester resin for toner according to claim 1, which has a glass transition temperature in the range of 48 to 58°C.

10. Toner particles containing the polyester resin for toner according to any one of claims 1 to 9.

11. A toner for developing electrostatic images, comprising the toner particles according to claim 10.

12. An electrostatic image developer comprising the toner for developing electrostatic images according to claim 11 and a carrier.

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