JP2010085629A - Method for producing crosslinked polyester resin for toner - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a crosslinked polyester resin for toner which has excellent low temperature fixability, high temperature offset resistance, a wide fixing temperature width, and excellent material dispersibility, developability and preservability. <P>SOLUTION: In the method for producing the crosslinked polyester resin for toner, two unsaturated polyester resins with different softening temperatures are melted and mixed at the shear energy of ≥0.05 kWh/kg, and thereafter, the mixture is crosslinked using a crosslinking initiator. The acid value of the unsaturated polyester resin with a lower softening temperature is preferably ≤10 mgKOH/g. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for producing a crosslinked polyester resin for toner.

  In the method of obtaining an image by the electrophotographic printing method and the electrostatic charge developing method, the electrostatic charge image formed on the photoreceptor is developed with toner charged in advance by friction and then fixed. As for the fixing method, there are a heat roller method in which a toner image obtained by development is fixed using a pressurized and heated roller, and a non-contact fixing method in which fixing is performed using an electric oven or flash beam light.

  In order to pass through these processes without any problem, the toner needs to maintain a stable charge amount first, and then needs to have good fixability to paper. In addition, since the apparatus includes a heating body in the fixing unit, the temperature rises in the apparatus, and thus the toner is required not to block in the apparatus.

  Recently, energy saving has been particularly demanded, and as a result, the temperature of the fixing unit has been lowered in the heat roller system. For this reason, the toner is strongly required to have a performance of fixing on paper at a lower temperature, that is, a low-temperature fixability. Moreover, in the heat roller system, since a so-called offset phenomenon occurs, it is assumed that offset resistance is required. Accordingly, it is necessary to develop a low-temperature fixing property that exhibits fixing on paper even under a fixing temperature of 120 ° C. or less, while maintaining offset resistance, and a wider working range, for example, a fixing temperature range of 80 ° C. or higher. There is a growing demand for toners to have.

  The binder resin for toner has a great influence on the toner characteristics as described above, and polystyrene resin, styrene-acrylic resin, polyester resin, epoxy resin, polyamide resin, etc. are known, but recently, transparent Polyester resin is especially attracting attention because it is easy to balance the fixing property and the fixing property.

  As means for improving the fixing property of the polyester resin for toner, studies have been made to introduce an unsaturated group into the linear polyester resin, and to react and crosslink with a polymerization initiator or the like under a specific shear energy.

  For example, Document 1 describes that a toner resin containing a crosslinked part and an uncrosslinked part is obtained by crosslinking reaction of an unsaturated polyester resin composed of fumaric acid and a bisphenol A propylene oxide adduct or the like. Yes.

Patent Document 2 describes a crosslinked polyester resin obtained by a crosslinking reaction of an unsaturated polyester resin having a peak molecular weight of 12,000 or more and a polyester resin having a peak molecular weight of less than 12,000.
JP-A-6-130722 WO2007-034813

  However, in the method of Patent Document 1, one kind of unsaturated polyester resin is used and the low-temperature fixability is not sufficient. In the method of Patent Document 2, although low-temperature fixability and storage stability are good, Is insufficient and the cross-linking reaction is not uniform, the dispersibility and developability of the colorant and the like in the toner are not sufficient.

  The present invention solves these problems and provides a crosslinked polyester resin for toner having a wide fixing temperature range because of excellent low-temperature fixability and high-temperature offset resistance, and excellent material dispersibility, developability, and storage stability. It is in.

  The gist of the present invention resides in a method for producing a crosslinked polyester resin in which two types of unsaturated polyester resins having different softening temperatures are melt-mixed at a shear energy of 0.05 kWh / kg or more and then subjected to a crosslinking reaction using a crosslinking reaction initiator. .

  By using the crosslinked polyester resin for toner according to the production method of the present invention, a toner having a wide fixing temperature range and excellent material dispersibility can be obtained because of excellent low temperature fixability and high temperature offset resistance.

  The crosslinked polyester resin obtained by crosslinking the unsaturated polyester resin exhibits excellent high-temperature offset resistance. Furthermore, by crosslinking the two types of unsaturated polyester resins having different softening temperatures, low-temperature fixability and high-temperature resistance. A resin excellent in offset balance can be obtained.

  In the present invention, two types of unsaturated polyester resins having different softening temperatures are melt-mixed at a shear energy of 0.05 kWh / kg or more before the cross-linking reaction, thereby enabling a uniform cross-linking reaction.

  When the shear energy is less than 0.05 kWh / kg, the two types of unsaturated polyester resins having different softening temperatures generate a non-uniform cross-linking component in the subsequent cross-linking reaction, which significantly impairs the material dispersibility of the toner.

  This lower limit is particularly preferably 0.1 kWh / kg. The upper limit is preferably 10 kWh / kg.

  Examples of the melt mixing device for setting the shear energy to 0.05 kWh / kg or more include, for example, a twin screw extruder, a single screw extruder, a roll kneader, a Brabender kneader, an injection molding machine, a static mixer and a supply pump. And a twin-screw extruder or a single-screw extruder is preferably used.

The shear energy is calculated by the following formula (1) by measuring the power value of the melt mixing apparatus and the resin discharge amount.
Shear energy (kWh / kg) = Power value of melt mixing device (kWh) / Resin discharge amount per hour (kg) (1)
In the present invention, after melting, mixing and mixing at a shear energy of 0.05 kWh / kg or more, a crosslinking reaction is performed using a crosslinking reaction initiator.

  The form of the crosslinking reaction of the unsaturated double bond is not particularly limited. For example, the unsaturated double bond in the unsaturated polyester resin is reacted by a radical addition reaction, a cation addition reaction, or an anion addition reaction, and the like. Reactions that produce carbon-carbon bonds are preferred.

  Reactions in which unsaturated double bonds in the polyester resin are reacted by radical addition reaction, cation addition reaction, anion addition reaction, etc. to generate an intermolecular carbon-carbon bond are performed by thermal reaction, photoreaction, redox reaction, etc. It can proceed by the active species generated. Of these, thermal reaction is preferable, and radical reaction is particularly preferable.

The radical reaction initiator is not particularly limited, and an azo compound or an organic peroxide is used. Among them, an organic peroxide is preferable because it has high initiator efficiency and does not generate a cyanide byproduct.
Among them, a reaction initiator having a high hydrogen abstraction ability is particularly preferable because the crosslinking reaction proceeds efficiently and the amount used is small, and benzoyl peroxide, di-t-butyl peroxide, t-butyl cumyl peroxide, Dicumyl peroxide, α, α-bis (t-butylperoxy) diisopropylbenzene, 2,5-dimethyl-2,5-bis (t-butylperoxy) hexane, di-t-hexyl peroxide, etc. Particularly preferred are initiators having a high hydrogen abstraction ability.

  It is preferable that the usage-amount of the initiator used for a crosslinking reaction is 0.01-5 mass parts with respect to 100 mass parts of unsaturated polyester resins.

  When the amount of the initiator used is less than 0.01 parts by mass, the crosslinking reaction of the unsaturated polyester resin does not proceed and the high temperature offset resistance of the toner is deteriorated. When the amount of the initiator used exceeds 5 parts by mass, the crosslinking reaction of the unsaturated polyester resin proceeds excessively and the high temperature offset resistance of the toner is deteriorated. The upper limit value is more preferably 3 parts by mass or less, further preferably 1 part by mass or less, and particularly preferably 0.5 part by mass or less.

  The time for performing the crosslinking reaction is preferably set in consideration of the 10-hour half-life temperature of the radical reaction initiator to be used. However, in consideration of the thermal decomposition reaction of the polyester resin, a range of 0.5 to 10 minutes is preferable. .

  The temperature at which the crosslinking reaction is carried out is preferably set in consideration of the 10-hour half-life temperature of the radical reaction initiator to be used, but considering the viscosity, thermal decomposition reaction, and crosslinking reactivity of the polyester resin, it is 100 ° C to 250 ° C. The range of is preferable.

  In addition, as a method of adding an initiator in the case of conducting a crosslinking reaction of unsaturated double bonds, it is preferable to prepare a mixture in which a crosslinking reaction initiator is dispersed in a diluent in advance and add this mixture to a polyester resin. .

By diluting the crosslinking reaction initiator with a diluent, the progress of the crosslinking reaction can be moderated, and the adjustment of the THF-insoluble matter tends to be facilitated.
Although the compound used as a diluent is not particularly limited, an acid compound or an alcohol compound used as a constituent component of a polyester resin may be used, or a low molecular weight polyester resin may be used as a diluent. In addition, polyalkyl carboxylic acid polyalkyl ester, phosphate ester, terpene resin, rosin resin, epoxy resin, polyalkylene glycol, silicone oil, mold release agent, etc. are used, and these are used in combination of two or more. May be.

  Among these, a release agent is particularly preferable. The diluent remains in the polyester resin for toner, but the release agent is used as an additive for the toner, so it does not adversely affect the toner performance even if it remains in the polyester resin for toner. Because. Furthermore, it is because the dispersibility of the release agent tends to be better than the case where the release agent is added to the polyester resin for toner in advance than when the release agent is added to the toner.

  When a release agent is used as a diluent for the radical reaction initiator, it is preferable to use one that does not inhibit the crosslinking reaction of unsaturated double bonds. As those that do not inhibit the crosslinking reaction of unsaturated double bonds, hydrocarbon-based release agents are preferred, for example, aliphatic hydrocarbon waxes such as low molecular weight polyethylene, low molecular weight polypropylene, microcrystalline wax, and paraffin wax; Examples thereof include oxides of aliphatic hydrocarbon waxes such as oxidized polyethylene wax; or block compounds thereof.

  Among these, the melting point of the release agent is preferably 120 ° C. or less because mixing with a radical reaction initiator is easy and the low-temperature fixability of the toner tends to be further improved. As the mold release agent having a melting point of 120 ° C. or less, paraffin wax is most preferable.

  The dilution rate of the crosslinking reaction initiator (mixing ratio of the crosslinking reaction initiator and the release agent) is not particularly limited, but the crosslinking reaction initiator / release agent (mass ratio) = 0.1 / 99.9 to 50 / A range of 50 is preferred. When this ratio is 0.1 / 99.9 or more, the crosslinking reaction tends to be caused efficiently, and when it is 50/50 or less, the self-induced decomposition tends to be suppressed.

  The unsaturated polyester resin has an unsaturated double bond in the main chain and / or side chain of the polyester resin. In order to have an unsaturated double bond in the main chain and / or side chain of the polyester resin, a polycondensation reaction using a carboxylic acid compound having an unsaturated double bond and / or an alcohol compound having an unsaturated double bond These compounds may be incorporated as a constituent component of the polyester resin.

  Examples of the carboxylic acid compound having an unsaturated double bond include, but are not limited to, fumaric acid, maleic acid, maleic anhydride, citraconic acid, itaconic acid, tetrahydrophthalic acid and ester derivatives thereof, acrylic acid, Examples include crotonic acid, methacrylic acid, and ester derivatives thereof. The alcohol compound having an unsaturated double bond is not particularly limited, and examples thereof include 1,4-dihydroxy-2-butene. Among these, at least one selected from fumaric acid, maleic acid, and maleic anhydride is particularly preferable from the viewpoint of reactivity.

  About the manufacturing method of unsaturated polyester resin, it does not restrict | limit in particular, It can manufacture using a well-known method. For example, the above-mentioned carboxylic acid compound having an unsaturated double bond and / or an alcohol compound having an unsaturated double bond, a carboxylic acid compound having no unsaturated double bond, and an alcohol having no unsaturated double bond A component derived from a compound is charged into a polymerization reaction kettle and polymerized through an esterification reaction or a transesterification reaction and a condensation reaction to produce an unsaturated polyester resin.

  In the polymerization of the unsaturated polyester resin, a polymerization catalyst such as titanium tetrabutoxide, dibutyltin oxide, tin acetate, zinc acetate, tin disulfide, antimony trioxide, germanium dioxide or the like can be used. The polymerization temperature is not particularly limited, but is preferably in the range of 180 ° C to 290 ° C.

  The unsaturated polyester resin can adjust the softening temperature by a condensation reaction after the esterification reaction. For example, the softening temperature can be increased by reducing the pressure inside the reaction vessel at a reaction temperature of 180 ° C. to 290 ° C. and advancing the reaction at a high vacuum. The end point of the reaction can be determined by measuring the softening temperature of the resin sampled from the reaction vessel or by converting the indicated value of the torque meter attached to the stirring blade of the reaction vessel into the softening temperature.

  The unsaturated polyester resin preferably has a linear structure. In order to make the unsaturated polyester resin into a linear structure, the unsaturated polyester resin has a carboxylic acid compound having an unsaturated double bond and / or an unsaturated double bond. In addition to the alcohol compound, the reaction may be carried out using a component derived from a divalent carboxylic acid compound having no unsaturated double bond and a divalent alcohol compound having no unsaturated double bond as main components. .

  Further, from a component derived from a monovalent carboxylic acid compound and / or a monovalent alcohol compound, a trivalent or higher carboxylic acid compound and / or a trivalent or higher alcohol compound to such an extent that a linear structure can be maintained. You may contain the structural component guide | induced as a structural component.

  The unsaturated double bond content in the unsaturated polyester resin is such that both the polyester resin having a low softening temperature and the polyester resin having a high softening temperature have a component having an unsaturated double bond as a carboxylic acid compound. The carboxylic acid compound is preferably 1 to 50 mol% in 100 mol% of the acid component constituting the polyester resin, and when the component having an unsaturated double bond is an alcohol compound, the alcohol compound Is preferably 1 to 50 mol% with respect to 100 mol% of the acid component constituting the polyester resin. Moreover, when using both together, it is preferable that the sum total of both is 1-50 mol%. In order to make the unsaturated double bond content of the unsaturated polyester resin within a preferable range, the preparation composition of the above-mentioned carboxylic acid compound having an unsaturated double bond and / or an alcohol compound having an unsaturated double bond is required. The unsaturated double bond content may be set in a preferable range.

  Moreover, in this invention, it is preferable that the softening temperature of unsaturated polyester resin with a low softening temperature is 120 degrees C or less. If it exceeds 120 ° C, the low-temperature fixability tends to deteriorate. The upper limit is more preferably 110 ° C. or less. This lower limit is preferably 80 ° C. or more from the viewpoint of storage stability.

Furthermore, the acid value of the unsaturated polyester resin having a low softening temperature is preferably 10 mgKOH / g or less.
When the acid value of the unsaturated polyester resin having a low softening temperature is 10 mg KOH / g or less, the developability of the toner is improved. When the acid value of the polyester resin having a low softening temperature exceeds 10 mgKOH / g, the developability of the toner tends to be lowered.

  The upper limit of the unsaturated polyester resin having a low softening temperature is more preferably 8 mgKOH / g, and particularly preferably 4 mgKOH / g. The lower limit is preferably 0.5 mgKOH / g.

  In order to set the acid value of the unsaturated polyester resin having a low softening temperature to 10 mgKOH / g or less, the ratio of the carboxylic acid compound and the alcohol compound constituting the polyester resin may be adjusted. For example, charged molar ratio = (alcohol compound) If the charged molar ratio is increased, the acid value of the unsaturated polyester resin can be reduced to 10 mgKOH / g or less.

  Further, the glass transition temperature (Tg) of the unsaturated polyester resin having a low softening temperature is not particularly limited, but when Tg is 45 ° C. or lower, extremely excellent low-temperature fixability can be obtained. This lower limit is preferably 30 ° C. or higher from the viewpoint of storage stability.

  In order to set the Tg of the unsaturated polyester resin having a low softening temperature to 45 ° C. or less, the charged molar ratio of the acid component and the alcohol component is increased to lower the molecular weight of the polyester resin, or an aliphatic alcohol compound such as ethylene glycol. Alternatively, the thermal mobility of the polyester skeleton may be increased by increasing the use ratio of 1,4-butanediol.

  The softening temperature of the unsaturated polyester resin having a high softening temperature is preferably 140 ° C. or higher. If it is lower than 140 ° C., the high temperature offset resistance tends to deteriorate. The lower limit is more preferably 150 ° C. or higher. This upper limit is preferably 200 ° C. or less from the viewpoint of low-temperature fixability.

  Moreover, it is preferable that unsaturated double bond content of unsaturated polyester resin with a high softening temperature is 15 mol% or less. By setting the content of unsaturated double bonds in the polyester resin having a high softening temperature to 15 mol or less, the crosslinking component obtained by the crosslinking reaction is not crosslinked at a high density, and a crosslinked network is uniformly formed in the resin. . Such a crosslinking component contributes to further imparting high-temperature offset resistance and storage stability.

  Furthermore, in such a crosslinked polyester resin, the material dispersibility is extremely good.

  The lower limit of the unsaturated double bond content of the unsaturated polyester resin having a high softening temperature is preferably 1 mol% or more from the viewpoint of the reactivity of the crosslinking reaction.

  In order to make the unsaturated double bond content of the unsaturated polyester resin within a preferable range, the preparation composition of the above-mentioned carboxylic acid compound having an unsaturated double bond and / or an alcohol compound having an unsaturated double bond is required. The unsaturated double bond content may be set in a preferable range.

  Furthermore, the blending ratio of the unsaturated polyester resin having a high softening temperature and the unsaturated polyester resin having a low softening temperature is not particularly limited, but is preferably 1/99 to 50/50 (mass ratio). When this blending ratio is within the above range, the low-temperature fixability and high-temperature offset resistance of the toner tend to be good. The blending ratio is more preferably 1/99 to 30/70, and particularly preferably 1/99 to 15/85.

  The crosslinked polyester resin for toner according to the production method of the present invention is obtained by crosslinking reaction of an unsaturated polyester resin and contains “THF insoluble matter” which is a crosslinking component having a high crosslinking density that does not dissolve in THF (tetrahydrofuran). To do.

  The THF-insoluble content is preferably 1-30% by mass. If the THF-insoluble content exceeds 30% by mass, the low-temperature fixability is greatly reduced. When the THF-insoluble content is less than 1% by mass, the high temperature offset resistance of the toner is lowered. The upper limit is more preferably 15% by mass.

  Next, a toner containing a polyester resin for toner, a release agent, and a colorant obtained by the production method of the present invention will be described.

  The content of the polyester resin for the toner is not particularly limited, but in the case of a magnetic toner containing magnetic powder, it is preferably 40 to 60% by mass in the total amount of toner, and in the case of a non-magnetic toner not containing magnetic powder Is preferably 80 to 95% by mass based on the total amount of toner.

  The toner may contain a resin such as a cyclic olefin resin, an epoxy resin, and a styrene-acrylic resin as a binder resin, if desired, in addition to the polyester resin produced by the production method of the present invention.

  Although it does not restrict | limit especially as a mold release agent, For example, the mold release agent whose melting | fusing point is the range of 60-130 degreeC is preferable. When the melting point of the release agent is 60 ° C. or higher, the toner has a tendency to have good blocking resistance, and when it is 130 ° C. or lower, the low-temperature fixability of the toner tends to be good.

  The type of release agent is not particularly limited, but is an aliphatic hydrocarbon wax such as low molecular weight polyethylene, low molecular weight polypropylene, microcrystalline wax, and paraffin wax; an oxide of aliphatic hydrocarbon wax such as oxidized polyethylene wax. Or block compounds thereof: deoxidized part or all of fatty acid esters such as carnauba wax, sazol wax, and montanic acid ester wax, and fatty acid esters such as deoxidized carnauba wax. Is mentioned.

  The content of the release agent is not particularly limited, but is preferably 0.1 to 10% by mass based on the total amount of toner.

  The colorant is not particularly limited, and known pigments, dyes and the like can be used. The colorants can be used alone or in admixture of two or more.

  The content of the colorant is not particularly limited, but is preferably in the range of 0.1 to 15% by mass based on the total amount of toner from the viewpoint of toner color tone, image density, charging stability, and thermal characteristics.

  The toner contains the above-described polyester resin, a release agent, and a colorant, and may contain various additives such as a charge control agent, a flow modifier, and a magnetic substance, if necessary. Good.

  When used as a two-component developer, it is used in combination with a carrier. As the carrier, a known material such as a magnetic substance such as iron powder, magnetite powder, or ferrite powder, a resin coating on the surface thereof, or a magnetic carrier can be used.

  Next, a method for producing the toner will be described.

  The toner is prepared by mixing the above-described polyester resin for a toner, a release agent, a colorant, and additives such as a charge control agent, a flow modifier, and a magnetic material, if desired, and then a twin-screw extruder, etc. And kneading, coarsely pulverizing, finely pulverizing, and classifying, and if necessary, can be produced by externally adding a flow modifier.

  In particular, in the kneading step, kneading is preferably performed at a temperature such that the temperature in the cylinder of the extruder is higher than the softening temperature of the polyester resin. Further, in the above process, a treatment such as making the toner particles spherical after fine pulverization to classification may be performed.

  Hereinafter, the present invention will be described with reference to examples. The evaluation was according to the following method.

(Softening temperature)
When using a flow tester CFT-500D (manufactured by Shimadzu Corporation) with a 1 mmφ × 10 mm nozzle at a load of 294 N (30 Kgf), a preheating time of 5 minutes, and a heating rate of 3 ° C./min, a sample of 1.0 g The temperature at which half of the effluent flowed was defined as the softening temperature.

(Acid value)
About 0.2 g of the sample was precisely weighed in a branched Erlenmeyer flask (A (g)), 10 ml of benzyl alcohol was added, and the resin was dissolved by heating in a nitrogen atmosphere for 15 minutes with a 230 ° C. heater. After cooling to room temperature, 10 ml of benzyl alcohol, 20 ml of chloroform, and several drops of phenolphthalein were added, and titrated with a 0.02 N KOH solution. (Titration volume = B (ml), titer of KOH solution = f). A blank measurement was performed in the same manner (titer amount = C (ml)), and calculation was performed according to the following formula.
Acid value (mgKOH / g) = {(BC) × 0.02 × 56.11 × f} / A
(THF insoluble)
About 2 g of Celite 545 (manufactured by Kishida Chemical Co., Ltd.) is placed in a cylindrical glass filter 1GP100 (manufactured by Shibata Chemical Co., Ltd.) having an inner diameter of 3.5 cm, and the glass filter is used until the height of the Celite 545 layer does not change. I tapped it lightly on the cork stand. This operation was repeated four times, and Celite 545 was filled into the glass filter so that the height of the Celite 545 layer was 2 cm from the filter surface. The glass filter filled with Celite 545 was dried at 105 ° C. for 3 hours or more and weighed (Yg). Next, about 0.5 g of the sample was put in an Erlenmeyer flask and precisely weighed (Xg), then 50 ml of THF was added, and the sample was dissolved under reflux of THF by heating in a 70 ° C. water bath for 3 hours.

This solution was put into a glass filter packed with Celite 545 and suction filtered. The glass filter capturing the THF-insoluble matter was dried at 80 ° C. for 3 hours or more, the weight was weighed (Zg), and the THF-insoluble matter was calculated according to the following formula.
THF-insoluble matter = (ZY) / X × 100 (mass%)
(Glass-transition temperature)
Using a differential differential calorimeter (DSC measuring device) and DSC-60 (manufactured by Shimadzu Corporation), 10 mg of a measurement sample is precisely weighed, put in an aluminum pan, and an aluminum pan containing alumina as a reference is used. When measured at a rate of temperature increase of 5 ° C./min, the temperature at the intersection of the base line of the chart and the tangent to the endothermic curve near the glass transition temperature was taken as the glass transition temperature.

(Maximum fixing temperature)
Using a copier “PAGEPREST N4-612 II” (manufactured by Casio Electronics Co., Ltd.), the temperature of the heat roller was changed, an unfixed image was produced, and the fixing temperature region was tested. The fixing roller used here is a fixing roller to which silicone oil is not applied, and has a nip width of 3 mm and a linear speed of 100 mm / second. Whether the solid image with a printing ratio of 1% printed on the top of A4 plain paper (manufactured by Daishowa Paper: BM64T) adheres to the roller by increasing the set temperature of the heat roller by 5 ° C and smears the bottom margin of the paper Was visually confirmed, and the highest setting temperature at which no contamination occurred was defined as the highest fixing temperature.
(Extremely good): Maximum fixing temperature of 200 ° C. or higher (Good): Maximum fixing temperature of 180 ° C. or higher and lower than 200 ° C. (Inferior): Maximum fixing temperature of lower than 180 ° C. (Minimum fixing temperature)
In accordance with the above measurement, the copying / fixing process was repeated until the temperature of the heat roller was reduced to 90 ° C. while decreasing the set temperature by 5 ° C., and the fixed image was subjected to a rubbing test. It was temperature.

For the fixing rate, use the printing paper used for the fixing temperature range evaluation, fold the printed portion and apply a load of 5 kg / cm 2, and then apply cellophane tape (Nitto Denko Packaging System, product number: N.29). The amount of light in the printed part before and after this operation was measured with a Macbeth light meter, and the fixing rate was calculated from the measured value.
Fixing rate (%) = (light quantity after cellophane tape peel test) / (light quantity before test) × 100 (%)
(Very good): minimum fixing temperature of 100 ° C. or lower (good): minimum fixing temperature of more than 100 ° C. to 120 ° C. (inferior): minimum fixing temperature of more than 120 ° C. (fixing temperature range)
The difference between the maximum fixing temperature and the minimum fixing temperature was defined as a fixing temperature range, and the determination was made according to the following criteria.
(Extremely good): Fixing temperature range of 100 ° C. or more (Good): Fixing temperature range of 80 ° C. or more and less than 100 ° C. (Inferior): Fixing temperature range of less than 80 ° C. (Developability)
Using a copier “PAGEPREST N4-612 II” (manufactured by Casio Electronics Co., Ltd.), unfixed images are drawn, and toner is fixed on paper under the conditions of a nip width of 3 mm, a linear speed of 100 mm / sec, and a heat roller temperature of 170 ° C. I let you. The magenta image density of this fixed image was measured using a spectral color difference meter NF777 manufactured by Nippon Denshoku Industries Co., Ltd. The measurement was performed twice, the average value was calculated, and judged according to the following criteria.
(Very good): Image density is 0.8 or higher (good): Image density is 0.7 or higher (inferior): Image density is 0.6 or lower (Material dispersibility)
The toner melt-kneaded product was cut using a microtome (HM 330 manufactured by Microme) to produce a thin slice for observation of about 1 to 3 μm. This observation thin piece was observed using a metal microscope (Eclipse ME600L manufactured by Nikon Corporation). The size of a circular or elliptical uncolored portion appearing in the observation visual field was used as a criterion for determining material dispersibility.
This uncolored portion is an excessively densified THF-insoluble matter derived from the binder resin. A colorant does not exist in such an uncolored part, and there are many uncolored parts, or that the part is large shows that material dispersibility is bad.
◎ (very good): no uncolored part is present at all (good): uncolored part having a major axis of 10 μm or less is present × (inferior): an uncolored part having a major axis exceeding 10 μm is present (Storability)
About 5 g of the toner was weighed and put into a sample bottle, which was left in a drier kept at 45 ° C. for about 24 hours, and the degree of toner aggregation was evaluated as an index of blocking resistance. The evaluation criteria were as follows.
◎ (very good): disperse by simply inverting the sample bottle ○ + (good): disperse by inverting the sample bottle and tapping 2-3 times ○ (available): inverting the sample bottle, 4 ~ Dispersion when tapped 5 times or more x (Inferior): Inverted sample bottle, does not disperse even when tapped 5 times or more (Example 1)
(Unsaturated polyester resin with low softening temperature)
A monomer component having a charging composition shown in Table 1 and 1000 ppm of dibutyltin oxide with respect to all acid components were charged into a reaction vessel equipped with a distillation tower. Next, the temperature was raised and heated so that the temperature in the reaction system was 265 ° C., and this temperature was maintained, and the reaction was continued until no water was distilled from the reaction system.

  Subsequently, the temperature in the reaction system was kept at 220 ° C., the pressure in the reaction vessel was reduced, and the reaction was continued. With the progress of the reaction, sampling and measuring the softening temperature are repeated, and when the softening temperature shown in Table 1 is reached, the reaction product is taken out and cooled to obtain an unsaturated polyester resin (resin A) having a low softening temperature. Obtained. The characteristic values of Resin A are shown in Table 1.

(Unsaturated polyester resin with high softening temperature)
A monomer component having a charging composition shown in Table 1 and 1500 ppm of antimony trioxide with respect to all acid components were charged into a reaction vessel equipped with a distillation tower. Next, the temperature was raised and heated so that the temperature in the reaction system became 260 ° C., and this temperature was maintained, and the esterification reaction was continued until no water was distilled from the reaction system. Subsequently, the temperature in the reaction system was set to 270 ° C., the pressure in the reaction vessel was reduced, and a condensation reaction was carried out while distilling the diol component from the reaction system. The reaction was carried out until the viscosity of the reaction system increased with the reaction, and the torque of the stirring blades showed a value that reached the desired softening temperature. And when the predetermined torque was shown, the reaction material was taken out and cooled, and unsaturated polyester resin (resin a) with a high softening temperature was obtained. Table 1 shows the characteristic values of the resin a.

  Next, paraffin wax (trade name SP-160: manufactured by Nippon Seiki Co., Ltd.): 1.35 parts by mass was heated to 70 ° C. and melted to obtain perhexa 25B (manufactured by Nippon Oil & Fats Co., Ltd .: 2,5-dimethyl- 0.15 parts by mass of 2,5-bis (t-butylperoxy) hexane 90%) was added, and the resulting mixture (paraffin wax / 2,5-dimethyl-2,5-bis (t- Butyl peroxy) hexane = 90/10) was cooled and ground to prepare a crosslinking reaction initiator I.

  Resin A: 0.9 Kg and Resin a: 0.1 Kg were supplied to a twin screw extruder PCM-30 (manufactured by Ikegai Kogyo Co., Ltd.) for melt mixing. Melt mixing was carried out in a twin screw extruder using conditions of an external temperature setting of 180 ° C., an extruder rotation speed of 100 rpm, a discharge rate of 2.4 kg / hour, and an average residence time of about 1 minute. The power value of the melt mixing apparatus was 0.5 kWh, and the shear energy of melt mixing was 0.2 kWh / kg.

After 1.5 parts by mass of the crosslinking initiator I was mixed with the obtained molten mixture, the mixture was supplied to a twin screw extruder PCM-30 (manufactured by Ikegai Kogyo Co., Ltd.) to carry out a crosslinking reaction. The crosslinking reaction was carried out in a twin-screw extruder using conditions of an external temperature setting of 180 ° C., an extruder rotation speed of 50 rpm, a discharge rate of 1.2 kg / hour, and an average residence time of about 3 minutes.
93 parts by weight of the obtained cross-linked polyester resin, 3 parts by weight of quinacridone pigment (E02 manufactured by Clariant), 3 parts by weight of carnauba wax (manufactured by Toyo Petrolide), and negative charge control agent (LR-147 manufactured by Nippon Carlit) ) 1 part by mass premixed, melt kneaded at 160 ° C. using a twin-screw extruder, coarsely pulverized, then finely pulverized with a jet mill fine pulverizer, adjusted toner particle size with a classifier, and average particle size A fine powder of 5 μm was obtained. To the obtained fine powder, silica (R-972, manufactured by Nippon Aerosil Co., Ltd.) was added so as to be 0.2% by mass, and mixed and adhered with a Henschel mixer to obtain toner 1. This toner was mounted on a non-magnetic one-component dry copying machine and its performance was evaluated. Table 2 shows the evaluation results of the toner.

(Comparative Example 1)
Resin A: 0.9 Kg, Resin a: 0.1 Kg, 1.5 parts by mass of cross-linking initiator I were mixed, and then melt-mixing was not performed, and twin screw extruder PCM-30 (manufactured by Ikegai Co., Ltd.) ) To carry out a crosslinking reaction. The crosslinking reaction was carried out in a twin-screw extruder using conditions of an external temperature setting of 180 ° C., an extruder rotation speed of 50 rpm, a discharge rate of 1.2 kg / hour, and an average residence time of about 3 minutes. The characteristic values of the obtained crosslinked polyester resin are shown in Table 2.

  Except for using the obtained cross-linked polyester resin, toner was formed in the same manner as in Example 1 to obtain a toner. Table 2 shows the evaluation results of the toner.

(Comparative Example 2)
Resin A and resin a are each heated to 200 ° C. to be in a molten state, and a gear pump is used to melt and mix polyester resin A and polyester resin a so that the blending ratio is A / a = 90/10 (mass ratio). The mixture was supplied to a static mixer (trade name Sulzer Mixer SMX-15A: 6 element: manufactured by Green Machinery Co., Ltd.), and the polyester resin A and the polyester resin a were melt mixed. The discharge amount was 3 kg / hour, the power value of the gear pump was 0.01 kWh, and the shear energy of the melt mixing was 0.003 kWh / kg.

  Subsequently, with respect to the obtained mixed polyester resin, the crosslinking reaction initiator I obtained in Example 1 using a feeder was added so as to be 1.5 parts by mass with respect to 100 parts by mass of the resin. Using a static mixer (trade name Sulzer Mixer SMX-15A: 12 element: manufactured by Green Machinery Co., Ltd.), the cross-linking reaction was performed while mixing the mixed polyester resin and the cross-linking initiator to obtain a cross-linked polyester resin. Table 2 shows the characteristic values of the crosslinked polyester resin.

  Except for using the obtained cross-linked polyester resin, toner was formed in the same manner as in Example 1 to obtain a toner. Table 2 shows the evaluation results of the toner.

(Example 2)
An unsaturated polyester resin (resin B) having a low softening temperature was obtained in the same manner as in Synthesis Example 1 except that the charged monomer composition was changed as shown in Table 1. Table 1 shows the characteristic values of the resin B.
A crosslinked polyester resin was obtained by performing a crosslinking reaction in the same manner as in Example 1 except that the resin B was used instead of the resin A. Table 2 shows the characteristic values of the crosslinked polyester resin.

  Except for using the obtained cross-linked polyester resin, toner was formed in the same manner as in Example 1 to obtain a toner. Table 2 shows the evaluation results of the toner.

(Example 3)
An unsaturated polyester resin (resin C) having a low softening temperature was obtained in the same manner as in Synthesis Example 1 except that the charged monomer composition was changed as shown in Table 1. The characteristic values of Resin C are shown in Table 1.
A crosslinked polyester resin was obtained by performing a crosslinking reaction in the same manner as in Example 1 except that the resin C was used instead of the resin A. Table 2 shows the characteristic values of the crosslinked polyester resin.

  Except for using the obtained cross-linked polyester resin, toner was formed in the same manner as in Example 1 to obtain a toner. Table 2 shows the evaluation results of the toner.

Example 4
An unsaturated polyester resin (resin b) having a high softening temperature was obtained in the same manner as in Synthesis Example 2 except that the charged monomer composition was changed as shown in Table 1. Table 1 shows the characteristic values of the resin b.
A cross-linked polyester resin was obtained by performing a cross-linking reaction in the same manner as in Example 1 except that the resin b was used instead of the resin a and the reaction initiator was used. Table 2 shows the characteristic values of the crosslinked polyester resin.

  Except for using the obtained cross-linked polyester resin, toner was formed in the same manner as in Example 1 to obtain a toner. Table 2 shows the evaluation results of the toner.

(Example 5)
A crosslinked polyester resin was obtained by performing a crosslinking reaction in the same manner as in Example 4 except that the resin C was used instead of the resin A. Table 2 shows the characteristic values of the crosslinked polyester resin.

  Except for using the obtained cross-linked polyester resin, toner was formed in the same manner as in Example 1 to obtain a toner. Table 2 shows the evaluation results of the toner.

Claims (4)

A method for producing a crosslinked polyester resin for toner, wherein two types of unsaturated polyester resins having different softening temperatures are melt-mixed at a shear energy of 0.05 kWh / kg or more and then subjected to a crosslinking reaction using a crosslinking reaction initiator. The method for producing a crosslinked polyester resin for toner according to claim 1, wherein the acid value of the unsaturated polyester resin having a low softening temperature is 10 mgKOH / g or less. The method for producing a crosslinked polyester resin for toner according to claim 1 or 2, wherein the unsaturated polyester resin having a low softening temperature has a glass transition temperature (Tg) of 45 ° C or lower. The method for producing a crosslinked polyester resin for toner according to any one of claims 1 to 3, wherein the unsaturated double bond content of the unsaturated polyester resin having a high softening temperature is 15 mol% or less.