JP2009229546A - Electrophotographic toner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide electrophotographic toner excellent in both of low temperature fixability and offset resistance, capable of giving an image with a high gloss and having excellent pulverizing properties. <P>SOLUTION: The electrophotographic toner includes, as a binder resin, a polyester L having a softening point of ≥80°C and <120°C and a polyester H having a softening point of 120 to 160°C, in a weight ratio of 70/30 to 95/5 of (polyester L/polyester H). The polyester L is a polyester obtained by condensation polymerization of an alcohol component containing an ethylene oxide adduct of bisphenol-A by 20 to 80 mol% and a carboxylic acid component containing an aromatic dicarboxylic acid compound and an aliphatic dicarboxylic acid compound. The polyester H is a polyester obtained by condensation polymerization of an alcohol component and a carboxylic acid component containing alkenyl succinic acid by 10 to 50 mol% and a polyvalent carboxylic acid compound having a valence of ≥3. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  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 or the like.

Typical properties required for the toner include low-temperature fixability and offset resistance. Therefore, as an attempt to achieve both low-temperature fixability and offset resistance, many toners that use a polyester resin having a low softening point and a polyester resin having a high softening point have been studied (see Patent Documents 1 to 3, etc.).
JP 2003-119351 A JP-A-60-214368 JP 2000-347451 A

  However, since polyester tends to generate an offset, if the blending ratio of the polyester having a high softening point is increased to prevent the offset, the gloss necessary for the color toner cannot be secured. Further, in recent years, a reduction in toner particle size is required from the viewpoint of high image quality, and in the melt-kneading pulverization method, if the blending ratio of the resin having a high softening point in the toner is large, the pulverization property in the pulverization process is lowered. Cause.

  An object of the present invention is to provide an electrophotographic toner that is excellent in both low-temperature fixability and offset resistance, can provide an image having a good gloss, and is excellent in grindability.

  In the present invention, as a binder resin, polyester L having a softening point of 80 ° C. or higher and lower than 120 ° C. and polyester H having a softening point of 120 to 160 ° C. are mixed in a weight ratio of 70/30 to 95/5 (polyester L / polyester H). The polyester L contains an alcohol component containing 20 to 80 mol% of an ethylene oxide adduct of bisphenol A, an aromatic dicarboxylic acid compound, and an aliphatic dicarboxylic acid compound. A polyester obtained by polycondensation of a carboxylic acid component contained therein, wherein the polyester H contains an alcohol component and alkenyl succinic acid in an amount of 10 to 50 mol%, and a trivalent or higher polyvalent carboxylic acid compound. The present invention relates to an electrophotographic toner, which is a polyester obtained by condensation polymerization with a carboxylic acid component.

  The toner for electrophotography of the present invention is excellent in both low-temperature fixability and offset resistance, provides an image having a good gloss, and has an excellent effect in grindability.

  The toner for electrophotography of the present invention contains, as a binder resin, a low-softening point polyester L having a specific softening point and a high softening point polyester H in a specific blending ratio. That is, the softening point of polyester L is 80 ° C. or higher and lower than 120 ° C., preferably 90 ° C. or higher and lower than 120 ° C., more preferably 100 ° C. or higher and lower than 120 ° C., more preferably 100 to 110 ° C. Is more preferable. On the other hand, the softening point of polyester H is 120 to 160 ° C., preferably 125 to 160 ° C., more preferably 130 to 155 ° C., and further preferably 135 to 155 ° C., from the viewpoint of offset resistance of the toner.

  In general, since polyester is easily offset, it is preferable to contain a large amount of polyester H having a high softening point from the viewpoint of offset resistance. However, when the blending ratio of the polyester H having a high softening point is increased, the gloss required for a color image is lowered. From the viewpoint of image gloss, low-temperature fixability and grindability of the toner, polyester L having a low softening point. A higher blending ratio is preferable. On the other hand, in this invention, since polyester L and polyester H are obtained using the specific raw material monomer mentioned later, compatibility of both polyesters is high and the compounding ratio of polyester H of the high softening point is high. Even if it is less, good offset resistance can be maintained. Therefore, the weight ratio of polyester L to polyester H (polyester L / polyester H) is 70/30 to 95/5, preferably 70/30 to 90/10, more preferably 75/25 to 85/15, 78/22 to 83/17 are more preferable.

  The polyester L is obtained by using an alcohol component and a carboxylic acid component as raw material monomers and subjecting them to condensation polymerization.

  Examples of the alcohol component include polyoxypropylene-2,2-bis (4-hydroxyphenyl) propane and polyoxyethylene-2,2-bis (4-hydroxyphenyl) propane, which are represented by the formula (I):

(In the formula, RO and OR are oxyalkylene groups, R is an ethylene and / or propylene group, x and y indicate the number of added moles of alkylene oxide, each being a positive number, and the sum of x and y. 1 to 16 is preferable, 1 to 8 is more preferable, and 1.5 to 4 is more preferable)
Aromatic diols such as alkylene oxide adducts of bisphenol represented by: ethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6 -Aliphatic diols such as hexanediol, 1,4-butenediol, 1,3-butanediol and neopentyl glycol, and trihydric or higher polyhydric alcohols such as glycerin. Among these, an alkylene oxide adduct of bisphenol A is preferable from the viewpoint of chargeability of the toner.

  The alcohol component of the polyester L contains 20 to 80 mol% of bisphenol A ethylene oxide adduct (BPA-EO) in the alcohol component. By using an ethylene oxide adduct of bisphenol A as the alcohol component, it is estimated that the number average molecular weight of the obtained polyester is higher than that of the polyester having the same softening point. That is, since the propylene oxide adduct has a rigid monomer structure, it requires a relatively small amount of monomer to react until reaching a predetermined softening point, whereas in the case of an ethylene oxide adduct, the monomer structure is soft. Many monomers react before reaching a predetermined softening point. Therefore, since the number average molecular weight of the polyester having a low softening point is almost the same as that of the high softening point resin, it is possible to prevent a non-uniform state of the binder resin due to a viscosity difference and the compatibility between the polyester L and the polyester H. In addition, it is possible to prevent toner pulverization, that is, deterioration of the pulverization property of the melt kneaded material of the toner material in the toner production process due to the non-uniform state of the binder resin due to the difference in viscosity. It is estimated to be.

  The content of BPA-EO is preferably 30 mol% or more from the viewpoint of toner offset resistance, and is preferably 70 mol% or less from the viewpoint of toner grindability. Therefore, from these viewpoints, the content of BPA-EO in the alcohol component of the polyester L is preferably 30 to 70 mol%, more preferably 40 to 60 mol%, and further preferably 45 to 55 mol%.

  In the alcohol component of polyester L, as the alcohol other than BPA-EO, a propylene oxide adduct of bisphenol A (BPA-PO) is preferable from the viewpoint of offset resistance of the toner. The content of BPA-PO in the alcohol component other than BPA-EO is preferably 70 mol% or more, more preferably 80 mol% or more, further preferably 90 mol% or more, and substantially 100 mol%. preferable.

  In the present invention, the ethylene oxide adduct of bisphenol A is preferably a compound in which R is an ethylene group in the alkylene oxide adduct of bisphenol A represented by formula (I), but within the range not impairing the effects of the present invention. In addition, a part of the ethylene group may be substituted with another alkylene group containing a propylene group. Similarly, the propylene oxide adduct of bisphenol A is preferably a compound in which R is a propylene group in the alkylene oxide adduct of bisphenol A represented by the formula (I), and within the range not impairing the effects of the present invention. It may be substituted with another alkylene group containing a group.

  Examples of carboxylic acid components include oxalic acid, malonic acid, maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, n-dodecyl succinic acid, n-dodecenyl succinic acid, etc. An aliphatic dicarboxylic acid such as phthalic acid, isophthalic acid and terephthalic acid; an alicyclic dicarboxylic acid such as cyclohexanedicarboxylic acid; a trivalent or higher polyvalent carboxylic acid such as trimellitic acid and pyromellitic acid; And anhydrides of these acids, alkyl (1 to 3 carbon atoms) esters; rosins; rosins modified with fumaric acid, maleic acid, acrylic acid, and the like. Such acids, anhydrides of these acids, and alkyl esters of these acids are collectively referred to herein as carboxylic acid compounds.

  The carboxylic acid component of the polyester L contains an aromatic dicarboxylic acid compound and an aliphatic dicarboxylic acid compound from the viewpoint of toner offset resistance, image gloss, and toner grindability. The aromatic dicarboxylic acid compound is preferably at least one selected from the group consisting of terephthalic acid, isophthalic acid and phthalic acid, from the viewpoint of toner pulverization. The aliphatic dicarboxylic acid compound is preferably at least one of fumaric acid and maleic acid from the viewpoint of toner offset resistance.

  The molar ratio of the aromatic dicarboxylic acid compound to the aliphatic dicarboxylic acid compound (aromatic dicarboxylic acid compound / aliphatic dicarboxylic acid compound) is determined from the viewpoints of toner offset resistance, image gloss, toner low-temperature fixability and grindability. 30/70 to 50/50 are preferred, 33/67 to 47/53 are more preferred, and 35/65 to 45/55 are even more preferred.

  The content of the aromatic dicarboxylic acid compound and the aliphatic dicarboxylic acid compound in the dicarboxylic acid compound is preferably 80 mol% or more, more preferably 90 mol% or more, from the viewpoint of toner grindability, offset resistance and image gloss. Preferably, 95 mol% or more is more preferable.

  The content of the dicarboxylic acid compound in the carboxylic acid component is preferably 90 mol% or more, more preferably 95 mol% or more, and even more preferably 99 mol% or more, from the viewpoint of image gloss.

  The carboxylic acid component of the polyester L contains a trivalent or higher polyvalent carboxylic acid compound as a carboxylic acid compound other than the aromatic dicarboxylic acid compound and the aliphatic dicarboxylic acid compound from the viewpoint of compatibility with the polyester H. It is preferable. The content of the trivalent or higher polyvalent carboxylic acid compound is preferably 0.05 to 10 mol%, more preferably 0.1 to 5 mol%, still more preferably 0.1 to 1 mol%, and more preferably 0.1 to 0.5 mol% in the carboxylic acid component. Is even more preferred.

  The alcohol component contains a monovalent alcohol, and the carboxylic acid component contains a monovalent carboxylic acid compound as appropriate from the viewpoint of adjusting the molecular weight of the polyester and improving the offset resistance of the toner containing the polyester. May be.

  The polycondensation of the alcohol component and the carboxylic acid component is carried out, for example, in an inert gas atmosphere, under reduced pressure, in the presence of an esterification catalyst such as tin (II) 2-ethylhexanoate, dibutyltin oxide, and the like. In the present invention, the polyester L and the polyester H can be used at least one of them from the viewpoint of improving the compatibility between them and improving the environmental stability of the toner and the gloss of the image. Either one is preferably a polyester having a block polymer structure by a two-stage reaction described later.

That is, polyester L is
(a1) a step of subjecting the alcohol component and the aromatic dicarboxylic acid compound to a condensation polymerization reaction; and
(b1) After the reaction rate in the step (a1) reaches 90% or more, preferably 95% or more, the aliphatic dicarboxylic acid compound is added to the reaction system and further subjected to a condensation polymerization reaction. It is preferable that In the present invention, the reaction rate means a value of product reaction water amount (mol) / theoretical product water amount (mol) × 100.

  In the step (a1), the condensation polymerization reaction is preferably performed in the presence of an esterification catalyst such as tin (II) 2-ethylhexanoate and dibutyltin oxide. The amount of the esterification catalyst used is preferably 0.05 to 0.7 parts by weight with respect to 100 parts by weight of the total amount of raw material monomers used in the step (a1). The reaction temperature is preferably 225 to 245 ° C, more preferably 230 to 235 ° C.

  In the step (b1), the condensation polymerization reaction is preferably performed in the presence of a polymerization inhibitor such as t-butylcatechol. The amount of the polymerization inhibitor used is preferably 0.003 to 0.2 parts by weight based on 100 weights of the total amount of raw material monomers. Also in step (b1), it is preferable to add 0.05 to 0.7 parts by weight of the esterification catalyst to the reaction system with respect to 100 parts by weight of fumaric acid. The reaction temperature is preferably 185 to 220 ° C, more preferably 195 to 215 ° C.

  Carboxylic acid components other than the aromatic dicarboxylic acid compound and the aliphatic dicarboxylic acid compound are preferably subjected to a condensation polymerization reaction in the step (a1).

  The glass transition point of the polyester L is preferably from 30 to 70 ° C, more preferably from 35 to 65 ° C, and even more preferably from 40 to 60 ° C, from the viewpoint of toner pulverization.

  The number average molecular weight of the polyester L is preferably 2000 to 4500, more preferably 2500 to 4000, and still more preferably 3000 to 3600, from the viewpoint of low-temperature fixability of the toner.

  Similarly to the polyester L, the polyester H is obtained by condensation polymerization using an alcohol component and a carboxylic acid component as raw material monomers. The same compounds are exemplified as the alcohol component and the carboxylic acid component, but as the alcohol component of polyester H, an alkylene oxide adduct of bisphenol A is preferable from the viewpoint of toner grindability, and a propylene oxide adduct (BPA- PO) and an ethylene oxide adduct (BPA-EO) of bisphenol A are preferably used in combination. The content of the bisphenol A alkylene oxide adduct is preferably 70 mol% or more, more preferably 80 mol% or more, and still more preferably 90 mol% or more in the alcohol component of polyester H from the viewpoint of low-temperature fixability of the toner. . Substantially 100 mol% is more preferable. The molar ratio of BPA-EO to BPA-PO (BPA-EO / BPA-PO) is 60/4 to 10/90 in terms of toner offset resistance, image gloss, and toner low-temperature fixability. Preferably, 40/60 to 20/80 is more preferable, and 45/65 to 25/75 is more preferable.

  The carboxylic acid component of the polyester H contains alkenyl succinic acid and a trivalent or higher polyvalent carboxylic acid compound from the viewpoint of environmental stability and offset resistance of the toner.

  By using alkenyl succinic acid as the carboxylic acid component, low temperature fixability and offset resistance are improved. The carbon number of the alkenyl group in the alkenyl succinic acid is preferably 8 to 16, more preferably 9 to 14, and further preferably 9 to 13 from the viewpoint of offset resistance of the toner. In addition, this carbon number means the average carbon number of the alkenyl group substituted by succinic acid.

  The content of alkenyl succinic acid is 10 to 50 mol%, preferably 15 to 45 mol%, more preferably 20 to 35 mol% in the carboxylic acid component, from the viewpoint of environmental stability of the toner and gloss of the image. 25 to 35 mol% is more preferable.

  As the dicarboxylic acid compound other than alkenyl succinic acid, an aromatic dicarboxylic acid compound is preferable from the viewpoint of pulverizing property of the toner, and at least one selected from the group consisting of terephthalic acid, isophthalic acid and phthalic acid is preferable.

  The content of the dicarboxylic acid compound is preferably 50 to 95 mol%, more preferably 60 to 90 mol%, and further preferably 65 to 85 mol% in the carboxylic acid component from the viewpoint of the gloss of the image.

  The trivalent or higher polyvalent carboxylic acid compound is preferably at least one selected from the group consisting of trimellitic acid, its lower alkyl (1 to 3 carbon atoms) ester, and anhydride from the viewpoint of pulverizing properties of the toner. Trimellitic acid and its anhydride are more preferable.

  The content of the trivalent or higher polyvalent carboxylic acid compound is preferably 5 to 50 mol%, more preferably 10 to 40 mol% in the carboxylic acid component, from the viewpoint of toner grindability and offset resistance. 35 mol% is more preferable.

Polyester H
(a2) a step of polycondensing the alcohol component and alkenyl succinic acid, and
(b2) After the reaction rate in step (a2) reaches 90% or more, preferably 95% or more, a step of adding a trivalent or higher polyvalent carboxylic acid compound to the reaction system and further subjecting it to a condensation polymerization reaction It is preferable that it is obtained by the method of including.

  In the step (a2), the condensation polymerization reaction is preferably performed in the presence of an esterification catalyst such as tin (II) 2-ethylhexanoate and dibutyltin oxide. The amount of the esterification catalyst used is preferably 0.05 to 0.7 parts by weight with respect to 100 parts by weight of the raw material monomer used in the step (a2). The reaction temperature is preferably 225 to 245 ° C, more preferably 230 to 235 ° C.

  In step (a2), in order to obtain a desired reaction rate, it is preferable to carry out the reaction under a reduced pressure of 2 to 10 kPa after carrying out a normal pressure reaction.

  In the step (b2), the reaction temperature is preferably 190 to 240 ° C, more preferably 200 to 220 ° C.

  Carboxylic acid components other than alkenyl succinic acid and trivalent or higher polyvalent carboxylic acid compounds are preferably subjected to a polycondensation reaction in step (a2).

  The glass transition point of the polyester H is preferably 40 to 80 ° C., more preferably 50 to 75 ° C., and further preferably 55 to 70 ° C. from the viewpoint of toner pulverization.

  The number average molecular weight of the polyester H is preferably 2000 or more and less than 3500, more preferably 2300 to 3300, and further preferably 2500 to 3100, from the viewpoint of low-temperature fixability and grindability of the toner.

  The total content of polyester L and polyester H is preferably 80% by weight or more, 90% by weight in the binder resin, from the viewpoints of offset resistance, grindability, low-temperature fixability, image gloss and environmental stability of the toner. The above is more preferable, 95% by weight or more is further preferable, and it is more preferable that it is substantially 100% by weight.

  The toner further includes a colorant, a charge control agent, a release agent, a magnetic powder, a fluidity improver, a conductivity regulator, an extender pigment, a reinforcing filler such as a fibrous substance, an antioxidant, an anti-aging agent, Additives such as a cleaning property improving agent may be appropriately contained.

  As the colorant, all of the dyes and pigments used as the colorant for the toner can be used. However, the toner of the present invention can provide a glossy image required for the color toner. The color toner preferably contains a chromatic colorant. As chromatic colorants, phthalocyanine blue, permanent brown FG, brilliant first scarlet, pigment green B, rhodamine-B base, solvent red 49, solvent red 146, solvent blue 35, quinacridone, carmine 6B, isoindoline, disazo yellow, etc. Can be mentioned. The content of the colorant is preferably 1 to 40 parts by weight and more preferably 2 to 10 parts by weight with respect to 100 parts by weight of the binder resin.

  As the charge control agent, any one of negative chargeability and positive chargeability can be used. Examples of the negatively chargeable charge control agent include metal-containing azo dyes, copper phthalocyanine dyes, metal complexes of salicylic acid alkyl derivatives, and nitroimidazole derivatives. Examples of the positively chargeable charge control agent include nigrosine dyes, triphenylmethane dyes, quaternary ammonium salt compounds, polyamine resins, imidazole derivatives, and the like. Also, a polymer type such as a resin can be used. The content of the charge control agent is preferably 0.1 to 8 parts by weight and more preferably 0.2 to 5 parts by weight with respect to 100 parts by weight of the binder resin.

  As release agents, aliphatic hydrocarbon waxes such as polypropylene, polyethylene, polypropylene polyethylene copolymer, microcrystalline wax, paraffin wax, Fischer-Tropsch wax and oxides thereof, carnauba wax, montan wax, sazol wax And ester waxes such as deoxidized wax, fatty acid amides, fatty acids, higher alcohols, fatty acid metal salts and the like, and these may be contained alone or in admixture of two or more. The content of the release agent is preferably 0.1 to 20 parts by weight, and more preferably 0.5 to 10 parts by weight with respect to 100 parts by weight of the binder resin.

  The electrophotographic toner of the present invention may be a toner obtained by any conventionally known method such as a melt-kneading method, an emulsion phase inversion method, or a polymerization method. From the viewpoint, a pulverized toner by a melt-kneading method is preferable. In the case of pulverized toner by the melt-kneading method, for example, raw materials such as a binder resin and a colorant are uniformly mixed with a mixer such as a Henschel mixer, and then a sealed kneader, a single or twin screw extruder, an open roll type It can be produced by melt-kneading with a kneader or the like, cooling, pulverizing and classifying. On the other hand, from the viewpoint of reducing the particle size of the toner, a toner by a polymerization method is preferable. An external additive such as hydrophobic silica may be added to the surface of the toner.

The volume median particle size (D ₅₀ ) of the toner is preferably 3 to 15 μm, more preferably 3 to 10 μm. In the present specification, the volume-median particle size (D ₅₀ ) means a particle size at which the cumulative volume frequency calculated by the volume fraction is 50% when calculated from the smaller particle size.

  The toner of the present invention can be used as a one-component developing toner or as a two-component developer mixed with a carrier.

[Softening point of resin]
Using a flow tester (Shimadzu Corporation, CFT-500D), a 1 g sample is heated at a heating rate of 6 ° C / min. While applying a load of 1.96 MPa with a plunger and extruded from a nozzle with a diameter of 1 mm and a length of 1 mm. . Plot the plunger drop amount of the flow tester against the temperature, and let the softening point be the temperature at which half of the sample flows out.

[Glass transition point of resin]
Using a differential scanning calorimeter (Seiko Denshi Kogyo Co., Ltd., DSC210), the temperature was raised to 200 ° C, and the sample was cooled to 0 ° C at a temperature drop rate of 10 ° C / min. The temperature at the intersection of the extended line of the baseline below the maximum peak temperature of endotherm and the tangent line indicating the maximum slope from the peak rising portion to the peak apex.

[Number average molecular weight of resin]
The number average molecular weight is obtained from a chart showing the molecular weight distribution by gel permeation chromatography obtained by the following method.
(1) Preparation of sample solution Dissolve the resin in tetrahydrofuran so that the concentration is 0.5 g / 100 mL. Next, this solution is filtered using a fluororesin filter (FP-200, manufactured by Sumitomo Electric Industries, Ltd.) having a pore size of 2 μm to remove insoluble components, thereby obtaining a sample solution.
(2) Molecular weight distribution measurement Using the following measuring device and analytical column, flow tetrahydrofuran at a flow rate of 1 mL per minute as a solution, and stabilize the column in a constant temperature bath at 40 ° C. Measurement is performed by injecting 100 μL of the sample solution. The molecular weight of the sample is calculated based on a calibration curve prepared in advance. For the calibration curve at this time, a sample prepared using several types of monodisperse polystyrene as a standard sample is used.
Measuring device: CO-8010 (manufactured by Tosoh Corporation)
Analytical column: GMHXL + G3000HXL (manufactured by Tosoh Corporation)

[Volume-median particle size of toner (D ₅₀ )]
In this specification, the volume-median particle size (D ₅₀ ) of the toner means the particle size of the toner in which the cumulative volume frequency calculated by the volume fraction is 50% calculated from the smaller particle size.
Measuring instrument: Coulter Multisizer II (Beckman Coulter, Inc.)
Aperture diameter: 50μm
Analysis software: Coulter Multisizer AccuComp version 1.19 (Beckman Coulter)
Electrolyte: Isoton II (Beckman Coulter)
Dispersion: Emulgen 109P (manufactured by Kao Corporation, polyoxyethylene lauryl ether, HLB: 13.6) 5% by weight Electrolyte dispersion condition: 10 mg of measurement sample was added to 5 mL of dispersion, and dispersed for 1 minute with an ultrasonic disperser. Thereafter, 25 mL of an electrolytic solution is added, and further dispersed with an ultrasonic disperser for 1 minute.
Measurement conditions: The dispersion is added to 100 mL of the electrolytic solution so that the particle size of 30,000 toner particles can be measured in 20 seconds, and 30,000 particles are measured. Determine the median particle size (D ₅₀ ).

Resin Production Example 1 [Resin L-1 to L-5, L-11 and L-12]
(Process (a1))
As shown in Tables 1 and 2, 50 g of tin (II) 2-ethylhexanoate as an alcohol component, a carboxylic acid component other than fumaric acid, and an esterification catalyst were equipped with a nitrogen introduction tube, a dehydration tube, a stirrer, and a thermocouple. In a 10-liter four-necked flask, the reaction rate reached 90% at 235 ° C. in a nitrogen atmosphere, and further reacted at 8 kPa for 2 hours until the reaction rate reached 97%.

(Process (b1))
The reaction product was cooled to 180 ° C., and fumaric acid shown in Tables 1 and 2, 50 g of tin (II) 2-ethylhexanoate as an esterification catalyst, and 5 g of t-butylcatechol as a polymerization inhibitor were added for 3 hours. The temperature was raised to 210 ° C. After further reaction for 2 hours, the reaction was allowed to proceed to a desired softening point at 17 kPa to obtain a polyester.

Resin Production Example 2 [Resin L-6 and L-8 to L-10]
As shown in Tables 1 and 2, 50 g of tin (II) 2-ethylhexanoate as the esterification catalyst, 5 g of t-butylcatechol as the polymerization inhibitor, nitrogen introduction tube, dehydration tube, stirrer And a 10-liter four-necked flask equipped with a thermocouple, and reacted under a nitrogen atmosphere at 230 ° C. for 5 hours and further at 17 kPa to the desired softening point to obtain a polyester.

Resin Production Example 3 [Resin L-7 and L-13]
As shown in Table 2, 50 g of tin (II) 2-ethylhexanoate as an alcohol component, a carboxylic acid component, and an esterification catalyst, four 10-liter volumes equipped with a nitrogen introduction tube, a dehydration tube, a stirrer, and a thermocouple It was put into a neck flask and reacted at 230 ° C. for 7 hours under a nitrogen atmosphere and further at 60 kPa to the desired softening point to obtain a polyester.

Resin Production Example 4 [Resin H-1]
(Process (a2))
As shown in Tables 1 and 2, 50 g of 2-ethylhexanoic acid tin (II) as an alcohol component, a carboxylic acid component other than trimellitic anhydride, and an esterification catalyst, a nitrogen introducing tube, a dehydrating tube, a stirrer and a thermocouple Place in a 10-liter four-necked flask equipped, and after reaching a reaction rate of 90% at 235 ° C in a nitrogen atmosphere, further react at 8kPa for 2 hours until the reaction rate reaches 97%. It was.

(Step (b2))
Cool the reaction product to 210 ° C, add trimellitic anhydride shown in Tables 1 and 2 and react for 1 hour at normal pressure, then react to 10 kPa to the desired softening point to obtain a polyester. It was.

Resin production example 5 [resins H-2 to H-4 and H-6]
As shown in Tables 1 and 2, 50 g of tin (II) 2-ethylhexanoate as an alcohol component, a carboxylic acid component, and an esterification catalyst were added in a 10-liter volume equipped with a nitrogen introduction tube, a dehydration tube, a stirrer, and a thermocouple. Place in a four-necked flask and react in a nitrogen atmosphere at 235 ° C until the reaction rate reaches 90%, then cool the reaction to 210 ° C over 1 hour and react at 10 kPa to the desired softening point. To obtain a polyester.

Resin Production Example 6 [Resin H-5]
As shown in Table 2, 50 g of tin (II) 2-ethylhexanoate as an alcohol component, carboxylic acid component, and esterification catalyst, and 5 g of t-butylcatechol as a polymerization inhibitor, a nitrogen introduction tube, a dehydration tube, a stirrer, and Place in a 10-liter four-necked flask equipped with a thermocouple, react at 210 ° C under a nitrogen atmosphere until the reaction rate reaches 90%, and then react at 10 kPa to the desired softening point. Obtained.

Resin Production Example 7 [Resin H-7]
(Process (a2))
As shown in Table 2, alcohol components, carboxylic acid components other than trimellitic anhydride, 50 g of tin (II) 2-ethylhexanoate as an esterification catalyst, and 5 g of t-butylcatechol as a polymerization inhibitor, nitrogen introduction tube, dehydration Place in a 10-liter four-necked flask equipped with a tube, stirrer, and thermocouple, reach a reaction rate of 90% at 235 ° C under a nitrogen atmosphere, and then react at 8 kPa for 2 hours. The reaction was allowed to reach 97%.

(Step (b2))
The reaction product was cooled to 210 ° C., trimellitic anhydride shown in Table 2 was added and reacted at normal pressure for 1 hour, and then reacted at 10 kPa to the desired softening point to obtain a polyester.

In Tables 1 and 2, the numerical value in parentheses of the raw material monomer is a molar ratio when the total amount of alcohol components is 100 mol, and abbreviations are as follows.
BPA-2PO: Polyoxypropylene (2.2) -2,2-bis (4-hydroxyphenyl) propane
BPA-2EO: Polyoxyethylene (2.2) -2,2-bis (4-hydroxyphenyl) propane
DSA: alkenyl succinic acid manufactured by Sanyo Chemical Industries (average carbon number of alkenyl group: 12)

Examples 1-12 and Comparative Examples 1-11
100 and 100 parts by weight of low softening point polyester and high softening point polyester shown in Tables 1 and 2, negative charge control agent "Bontron E-84" (manufactured by Orient Chemical Co., Ltd.), polypropylene wax "NP-105" (Mitsui Chemicals) 1 part by weight and Pigment Yellow 185 (Paliotol Yellow D1155: manufactured by BASF) 3 parts by weight were premixed, then melt-kneaded at 100 ° C. with a twin screw extruder, cooled, Crushed. Further, the toner particles having a volume-median particle size (D ₅₀ ) of 7.5 μm were obtained through pulverization and classification using a jet mill IDS2 type (manufactured by Nippon Pneumatic Co., Ltd.).

  When the coarsely pulverized product was finely pulverized with a jet mill IDS2 type (manufactured by Nippon Pneumatic Co., Ltd.), the volume median particle size of the pulverized product obtained when the processing speed was 150 g / min was measured, and the following The grindability was evaluated according to the evaluation criteria. The results are shown in Tables 1 and 2. The smaller the particle size, the better the grindability.

〔Evaluation criteria〕
A: Less than 7.0 μm B: 7.0 μm or more, less than 8.0 μm C: 8.0 μm or more, less than 9.0 μm D: 9.0 μm or more, less than 10.0 μm E: 10.0 μm or more

  To 100 parts by weight of the obtained toner particles, 1 part by weight of hydrophobic silica “NY-50” (manufactured by Nippon Aerosil Co., Ltd.) and 1 part by weight of hydrophobic silica “H3004” (manufactured by Wacker) are removed using a Henschel mixer. In addition, a yellow toner was obtained.

Test Example 1 [low temperature fixability]
The toner was mounted on the non-magnetic one-component developing device “Microline 5400” (Oki Data Co., Ltd.), and an unfixed image having a solid image portion of 2 cm × 3 cm (toner adhesion amount: 1.1 mg / cm ² ) was obtained. . Using the external fixing machine (fixing speed: 300mm / sec) of the non-magnetic one-component developing device "Microline3050" (Oki Data Co., Ltd.), while gradually increasing the fixing temperature from 140 ° C to 180 ° C in steps of 5 ° C, The unfixed image was fixed.

  Next, “Scotch (registered trademark) mending tape 810” (manufactured by Sumitomo 3M, width: 18 mm) was pasted on the fixed image, rubbed from above with a weight of 1.25 kg, and then the tape was peeled off. The image density before and after the tape was peeled off was measured using an image density measuring instrument “GURETAG SPM50” (manufactured by GURETAG), and the ratio between the two (after peeling / before sticking × 100) was calculated. %, The low-temperature fixing property was evaluated according to the following evaluation criteria. The lower the minimum fixing temperature, the better the low-temperature fixing property. The results are shown in Tables 1 and 2. The paper used for the fixing test is L paper manufactured by XEROX.

〔Evaluation criteria〕
A: Minimum fixing temperature is less than 150 ° C B: Minimum fixing temperature is 150 ° C or more and less than 160 ° C C: Minimum fixing temperature is 160 ° C or more and less than 170 ° C D: Minimum fixing temperature is 170 ° C or more

Test Example 2 [Offset resistance]
In Test Example 1, the presence or absence of hot offset was confirmed when fixing an unfixed image, and the offset resistance was evaluated according to the following evaluation criteria. The higher the hot offset occurrence temperature, the better the offset resistance. The results are shown in Tables 1 and 2.

〔Evaluation criteria〕
A: Hot offset generation temperature is 190 ° C or higher B: Hot offset generation temperature is 180 ° C or higher and lower than 190 ° C C: Hot offset generation temperature is 170 ° C or higher and lower than 180 ° C D: Hot offset generation temperature is lower than 170 ° C

Test Example 3 [Environmental stability]
After mounting toner on the non-magnetic one-component developing device "Microline 5400" (Oki Data Co., Ltd.) and leaving it in a high-temperature, high-humidity (HH) environment (35 ° C / 80RH%) for 24 hours, a solid image of 2cm x 3cm 500 images were printed, and the image density of the 500th sheet was measured using an image density measuring device “GURETAG SPM50” (manufactured by GURETAG). After leaving it in a low-temperature, low-humidity (LL) environment (10 ° C / 10RH%) for 24 hours, 500 solid images of 2cm x 3cm are printed, and the image density of the 500th sheet is measured by the image density measuring instrument “GURETAG SPM50” ( GURETAG). The difference between the image density of the 500th sheet in the HH environment and the image density of the 500th sheet in the LL environment was calculated, and the environmental stability was evaluated according to the following evaluation criteria. The smaller the image density difference between the HH environment and the LL environment, the better the environmental stability. The results are shown in Tables 1 and 2.

〔Evaluation criteria〕
Difference in image density between HH environment and LL environment: A: Less than 0.2 B: 0.2 or more, less than 0.4 C: 0.4 or more, less than 0.6 D: 0.6 or more, less than 0.8 E: 0.8 or more

Test Example 4 [Gloss of Image]
The toner was mounted on a full-color printer “MicroLine 9500PS” (Oki Data Co., Ltd.), a solid image was printed, and the glossiness was measured. The glossiness was measured using a gloss meter “PG-1” (Nippon Denshoku Industries Co., Ltd.) with the light source set at 60 °. The gloss was evaluated according to the following evaluation criteria. The higher the glossiness, the better the gloss. The results are shown in Tables 1 and 2.

〔Evaluation criteria〕
A: Glossiness of 20 or more B: Glossiness of 15 or more and less than 20 C: Glossiness of 10 or more and less than 15 D: Glossiness of less than 10

  From the above results, in comparison with Comparative Examples 1 to 11, the toners of Examples 1 to 12 are excellent in all of grindability, low-temperature fixability, offset resistance and environmental stability, and have an excellent gloss. It can be seen that In particular, it is clear that the toners of Examples 1 to 7 containing only the polyester obtained by the two-stage reaction have even better characteristics.

  The toner for electrophotography of the present invention is suitably used for developing a latent image formed in electrophotography, electrostatic recording method, electrostatic printing method and the like.

Claims (5)

  As a binder resin, polyester L having a softening point of 80 ° C. or higher and lower than 120 ° C. and polyester H having a softening point of 120 to 160 ° C. are contained in a weight ratio of 70/30 to 95/5 (polyester L / polyester H). A toner for electrophotography, wherein the polyester L contains an alcohol component containing 20 to 80 mol% of an ethylene oxide adduct of bisphenol A, and an carboxylic acid containing an aromatic dicarboxylic acid compound and an aliphatic dicarboxylic acid compound. A polyester obtained by polycondensation of a component, wherein the polyester H contains an alcohol component and an alkenyl succinic acid in an amount of 10 to 50 mol% and a trivalent or higher polyvalent carboxylic acid compound; An electrophotographic toner, which is a polyester obtained by condensation polymerization.   The toner for electrophotography according to claim 1, wherein the number average molecular weight of the polyester H is 2000 or more and less than 3500. Polyester L is
(a1) a step of subjecting the alcohol component and the aromatic dicarboxylic acid compound to a condensation polymerization reaction; and
(b1) After the reaction rate in the step (a1) reaches 90% or more, the aliphatic dicarboxylic acid compound is added to the reaction system, and further obtained by a method including a step of polycondensation reaction. Item 3. The toner for electrophotography according to Item 1 or 2. Polyester H
(a2) a step of polycondensing the alcohol component and alkenyl succinic acid, and
(b2) Obtained by a method comprising a step of adding a trivalent or higher polyvalent carboxylic acid compound to the reaction system after the reaction rate in step (a2) reaches 90% or more and further subjecting it to a polycondensation reaction The toner for electrophotography according to any one of claims 1 to 3.   The toner for electrophotography according to any one of claims 1 to 4, comprising a chromatic colorant.