JP3177019B2 - Binder resin composition for positively chargeable toner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a binder resin composition for a toner used for a full-color toner used in an electrophotographic method, an electrostatic printing method, etc., which is excellent in non-offset properties, fixability and blocking resistance. An object of the present invention is to provide a binder resin composition for toner which exhibits excellent positive chargeability and has no environmental pollution.

[0002]

2. Description of the Related Art The performance required of a toner and a binder resin for a toner used in a full-color copying machine or a full-color printer by an electrophotographic method is firstly a color mixing property and a blocking resistance during storage of the toner. Secondly, there is a charging characteristic that affects image formation. With respect to color mixing properties, toners and binder resins for toners which are excellent in fluidity and are sharp melt are used. Regarding the blocking resistance, it is important that the toner does not cause blocking even when the temperature at the time of storing the toner is high, and a binder resin having a relatively high glass transition temperature is used as the binder resin for the toner.

[0003] Further, the charging characteristics that most affect the image formation are important, and are roughly classified into the charging amount and the charging stability (moisture resistance). Regarding the charge amount, the charge amount of the toner and the binder resin for the toner must be determined by the photoreceptor such as a copying machine or a printer.The charge amount of the toner binder resin is controlled by the monomer and molecular structure used. Was. Regarding the charge stability, it is necessary that the charge amount does not change with time during printing and that the charge amount of the toner does not decrease at high humidity. For the binder resin for toner, this has been prevented by a resin manufacturing method. Was.

There are two types of charging of toner and toner binder resin: negative charging and positive charging. The charging amount of a negative charging toner is adjusted by a negative charging resin and a negative charging controller. Is done. Also, in the case of the positively chargeable toner, similarly to the negatively chargeable toner, a positively chargeable resin and a charge control agent are used, but the control of the charge amount of the positively chargeable toner has many problems. In addition, various studies have been conducted on positively chargeable binder resins for toner. In particular, in polyester copolymers that have been used as binder resins for full-color toners,
Although the use of various positively chargeable monomers has been studied, it has been difficult to improve the positively chargeable property because the ester bond exhibits a very strong negative charge. Therefore, a method of improving the positive chargeability of a polyester copolymer by blending a styrene-acrylic copolymer using a monomer containing an amino group or an amide group has been performed.

[0005]

However, in such a styrene-acrylic copolymer using a monomer containing an amino group or an amide group, it is necessary to use an azo type polymerization initiator in the polymerization. In addition, there is a problem that the toner has poor moisture resistance and poor charging stability, and has different thermal characteristics of the toner, resulting in poor color development of the toner. In addition, azobisisobutyronitrile, which is generally used as an azo-based polymerization initiator, has a problem of environmental pollution since a toxic substance having a CN group is generated as a decomposition by-product. Further, the use of the styrene-acrylic copolymer has a problem that the characteristics of the polyester copolymer such as fixability and high resolution are impaired. Accordingly, an object of the present invention is to provide a binder resin composition which is suitable for a full-color toner having excellent moisture resistance and excellent charge stability and having excellent positive chargeability without environmental pollution.

[0006]

In view of such circumstances, the present inventors have conducted intensive studies on resins for full-color toners. As a result, a specific polyester copolymer having a sharp melt and high resolution and an excellent positive charge have been obtained. It has been found that a binder resin for a full-color toner excellent in positive chargeability can be obtained by blending with a specific styrene-acrylic copolymer having a property. That is, the binder resin composition for a positively chargeable toner of the present invention comprises 60 to 95% by weight of a polyester copolymer composed of an acid component composed of a dicarboxylic acid and a diol component containing a bisphenol A-type aromatic diol; A styrene-acrylic copolymer containing 1 to 40% by weight of an acrylate component and / or a methacrylate component having a glass transition temperature of 40 to 68 ° C and a softening temperature of 80 to 80%. 125 ° C, acid value 20
mgKOH / g or less.

The polyester copolymer used in the present invention comprises a dicarboxylic acid component and a diol component containing a bisphenol A-type aromatic diol, and may be linear, branched or crosslinked. Can be used.
Examples of the bisphenol A-type aromatic diol constituting the polyester copolymer include bisphenol A, hydrogenated bisphenol A, and polyoxypropylene- (2,
4) -2,2-bis (4-hydroxyphenyl) propane, polyoxyethylene- (2,4) -2,2-bis (4-hydroxyphenyl) propane and the like, and these bisphenol A type aromatic diols Can be used alone or in combination of two or more. Among them,
Polyoxypropylene- (2,4) -2,2-bis (4
-Hydroxyphenyl) propane and polyoxyethylene- (2,4) -2,2-bis (4-hydroxyphenyl) propane are preferred. These bisphenol A-type aromatic diols are preferably contained in the range of 10 to 90 mol%, more preferably 20 to 90 mol%, based on the total acid components.
~ 80 mol%.

Other diol components include, for example, ethylene glycol, diethylene glycol, triethylene glycol, polyethylene glycol, propylene glycol, butanediol, neopentyl glycol, cyclohexane dimethanol, etc., and ethylene glycol and neopentyl glycol are particularly preferred. preferable. As the dicarboxylic acid component, for example, terephthalic acid, isophthalic acid, phthalic acid, maleic acid, fumaric acid, metaconic acid, citraconic acid, itaconic acid, glutaconic acid, cyclohexanedicarboxylic acid, succinic acid, alkenylsuccinic acid, adipic acid, sebacin Examples thereof include acids, malonic acid, linoleic acid and acid anhydrides thereof, and these dicarboxylic acids can be used alone or in combination of two or more. Among them, terephthalic acid, isophthalic acid and fumaric acid are preferred.

The polyester copolymer used in the present invention has a glass transition temperature of 40 to 68 ° C., a softening temperature of 80 to 125 ° C., an acid value of 20 mg KOH / g or less, and an average weight molecular weight of 3000 to 20,000. Are preferred. This is because if the glass transition temperature is less than 40 ° C., the blocking resistance of the toner tends to be inferior, and if it exceeds 68 ° C., the fixability of the toner tends to be impaired. If the softening temperature is lower than 80 ° C., the non-offset property of the toner tends to be inferior, and if it exceeds 125 ° C., the sharp melt property of the toner tends to be inferior. Further, when the acid value exceeds 20 mgKOH / g, the moisture resistance of the toner tends to be poor. Polymerization average molecular weight is 3
If it is less than 000, the blocking resistance of the toner tends to be inferior, and if it exceeds 20,000, the sharp melt property of the toner tends to be inferior and the color mixing property tends to be inferior, more preferably from 5,000 to 18,000. It is.

As a method for producing the polyester copolymer, a usual polyester condensation polymerization method is used. However, in consideration of the molar ratio between the total acid component and the total diol component according to the concentration of the dicarboxylic acid component, direct esterification is carried out. A method in which condensation is carried out after carrying out the conversion method or transesterification method is preferred.
In the production, a polymerization catalyst such as titanium butoxide, dibutyltin oxide, tin acetate, zinc acetate, tin disulfide, antimony trioxide, and germanium dioxide can be used. Among them, dibutyltin oxide, antimony trioxide, zinc acetate Is preferred.

The acrylate component or methacrylate component having an ether group used in the present invention includes, for example, 2-ethoxyethyl acrylate,
Examples include 2-methoxyethyl acrylate, 2-butoxyethyl acrylate, 2-ethoxyethyl methacrylate, 2-methoxyethyl methacrylate, and 2-butoxyethyl methacrylate. Of these, 2-ethoxyethyl methacrylate is particularly preferable. In the present invention, these acrylate components or methacrylate components having an ether group may be used alone or in combination of two or more.

The amount of the acrylate component or the methacrylate component having an ether group must be 1 to 40% by weight, preferably 5 to 30% by weight, based on the whole polymer component. . this is,
If the amount used is less than 1% by weight, it is difficult to obtain a satisfactory charge amount due to inferior positive chargeability. Conversely, if the amount used exceeds 40% by weight, the glass transition temperature of the toner is lowered and the anti-blocking property is obtained. This is because the properties are inferior.

As the components other than the above-mentioned acrylate component or methacrylate component having an ether group constituting the styrene-acrylic copolymer of the present invention, styrene component, acrylate component, methacrylate component or And unsaturated dibasic acid components. The amount of the styrene component, acrylate component, methacrylate component, unsaturated dibasic acid component, etc. used is selected according to the glass transition temperature, softening temperature and acid value of the binder resin of the present invention. It is used in the range of 60 to 99% by weight, preferably 70 to 95% by weight in the total polymer component in the total amount of the components.
Further, in these components, a combination with a styrene component, an acrylate component and a methacrylate component, a combination with an acrylate component and a methacrylate component, a styrene component, an acrylate component and / or a methacrylic acid component. Ester component,
Combinations with unsaturated dibasic acid components are particularly preferred.

The styrene component used in the styrene-acrylic copolymer of the present invention includes, for example, styrene,
o-methylstyrene, m-methylstyrene, p-methylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, 3,4-dichlorostyrene,
p-ethylstyrene, 2,4-dimethylstyrene, p-
n-butylstyrene, p-tertbutylstyrene, p
-N-hexylstyrene, pn-octylstyrene,
pn-nonylstyrene, pn-decylstyrene, p
-N-dodecylstyrene, α-methylstyrene and the like. Among them, styrene, p-methylstyrene and α-methylstyrene are particularly preferred. By using such a styrene component, the moisture resistance of the toner can be improved.

The acrylate component or methacrylate component is a component other than the acrylate component or methacrylate component having an ether group. As the acrylate component,
For example, acrylic acid, ethyl acrylate, methyl acrylate, n-butyl acrylate, isobutyl acrylate,
Propyl acrylate, 2-ethylhexyl acrylate,
Examples thereof include stearyl acrylate and lauryl acrylate, among which n-butyl acrylate and 2-ethylhexyl acrylate are particularly preferable. Examples of the methacrylate component include, for example, methacrylic acid, ethyl methacrylate, methyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, propyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, lauryl methacrylate, Examples thereof include glycidyl methacrylate, cyclohexyl methacrylate, diethylaminoethyl methacrylate, and dimethylaminoethyl methacrylate. Among them, methacrylic acid, methyl methacrylate, and n-butyl methacrylate are particularly preferable. Such an acrylate component or a methacrylate component can improve the positive chargeability of the toner,
It is easy to obtain a synergistic effect with an acrylate component or a methacrylate component having an ether group.

Further, examples of the unsaturated dibasic acid component include maleic acid, butyl maleate, methyl maleate, dimethyl maleate, fumaric acid, butyl fumarate, and the like.
Examples thereof include dibutyl fumarate, diisobutyl fumarate, dimethyl fumarate, and diethyl fumarate. Of these, dibutyl fumarate is particularly preferred. By using such an unsaturated dibasic acid component, it is possible to improve the positive chargeability of the toner.

In the present invention, any component other than the styrene component, acrylic ester component, methacrylic ester component and unsaturated dibasic acid component may be used as long as it has a double bond capable of radical polymerization. Can be used. Examples thereof include vinyl aliphatic carboxylic acid ester components such as vinyl acetate, vinyl propionate, vinyl caproate, and vinyl laurate, with vinyl acetate being particularly preferred. Further, a reaction with a butadiene-based monomer and an unsaturated polyester may be performed.

In the styrene-acrylic copolymer of the present invention, a chain transfer agent component may be used as a softening temperature and molecular weight regulator. Examples of the chain transfer agent component include α-methylstyrene dimer, Examples include n-dodecyl mercaptan, thioglycolic acid ester, and n-octyl mercaptan, and among them, α-methylstyrene dimer and thioglycolic acid ester are particularly preferable. As the molecular structure of the styrene-acrylic copolymer of the present invention, those having a crosslinked structure, those having a non-crosslinked structure having one or more peaks in a high molecular weight region and one or more peaks in a low molecular weight region in the molecular weight distribution, and those having one or more Those having one or more peaks can be cited, and can be appropriately selected in consideration of the fixing property and non-offset property of the toner.

The compound having a crosslinked structure contains 1 to 75% of a component (gel fraction) insoluble in a solvent such as tetrahydrofuran or chloroform. The monomer that provides a crosslinked structure is not particularly limited as long as it forms a crosslinked structure in the reaction.For example, aromatic divinyl compounds such as divinylbenzene and divinylnaphthalene, ethylene glycol diacrylate, and triethylene diacrylate Glycol, tetraethylene glycol diacrylate, polyethylene glycol diacrylate, propylene glycol diacrylate, 1,3-butylene glycol diacrylate, trimethylolpropane triacrylate, tetramethylol methane triacrylate, tetramethylol methane tetraacrylate, bisphenol A Derivative-based acrylates and the like, and those obtained by changing acrylic acid of these compounds to methacrylic acid, and the like are listed.

In the non-crosslinked structure having one or more peaks in each of a high molecular weight region and a low molecular weight region in the molecular weight distribution, a compound having a molecular weight in the molecular weight distribution of 3 × 10 ⁵
Having one or more peaks in the superpolymer region of ~ 2 × 10 ⁶ ,
A binder resin having one or more peaks in a low molecular weight region having a molecular weight of 3 × 10 ³ to 8 × 10 ⁴ is preferable. In addition, the binder resin having one or more peaks in the molecular weight distribution is a binder resin having a non-crosslinked structure having one or more peaks in the molecular weight distribution separately from the above-mentioned non-crosslinked structure.

The styrene-acrylic copolymer used in the present invention has a glass transition temperature of 40 ° C. or more, a softening temperature of 80 to 125 ° C., an acid value of 20 mg KOH / g or less, and an average weight molecular weight of 3,000 to 30,000. Is preferred. When the glass transition temperature is lower than 40 ° C., the blocking resistance of the toner tends to be inferior, and more preferably in the range of 50 to 65 ° C. If the softening temperature is lower than 80 ° C., the blocking resistance of the toner tends to be inferior, and if it exceeds 125 ° C., the sharp melt property of the toner tends to be inferior and the color mixing property tends to be poor. Preferably it is in the range of 85 to 120 ° C. Further, if the acid value exceeds 20 mgKOH / g, the moisture resistance of the toner tends to be inferior, and more preferably 1 to 1.
The range is 5 mgKOH / g or less. By controlling the polymerization average molecular weight in this range, excellent positive chargeability can be exhibited, and the weight average molecular weight is 3,000.
If it is less than 3, the glass transition temperature tends to be low and the blocking resistance of the toner tends to be inferior. Conversely, if it exceeds 30,000, the sharp melt property of the toner tends to be inferior and the color mixing property tends to be poor, which is more preferable. Is 5,000
It is in the range of 25,000.

Examples of the method for producing the styrene-acrylic copolymer of the present invention include methods such as bulk polymerization, suspension polymerization, emulsion polymerization, and solution polymerization. Even when two or more of these polymerization methods are used in combination, Good. These production methods are preferably selected according to the required characteristics of the toner.

The polymerization initiator used in the production of the binder resin of the present invention is not particularly limited as long as it is used for ordinary radical polymerization. Is particularly preferred. Examples of the peroxide-based polymerization initiator include benzoyl peroxide, t-butylperoxyisobutyrate, t-butylperoxy 2-ethylhexanoate, t-butylperoxybenzoate, and t-butylperoxy. Examples thereof include isopropyl carbonate and di-t-butyl diperoxyisophthalate. These may be used alone or in combination of two or more.
Among them, benzoyl peroxide and t-butylperoxybenzoate are particularly preferred. Further, 2,2′-azobis (2-methylbutyronitrile), 2,2′-azobis (2,4′-dimethylvaleronitrile), 1,1-bis (t-butylperoxy) 3,3,3 5-trimethylcyclohexane, 1,1-azobis (cyclohexane-1-
Carbonitrile), 2,2′-azobis (2,4,4-
Even if an azo-based polymerization initiator such as trimethylpentane) is used, the effect of positive charging can be obtained.

When the styrene-acrylic copolymer of the present invention is produced by emulsion polymerization or suspension polymerization, ordinary emulsifiers and dispersants can be used. Examples of the emulsifier and dispersant include polyvinyl alcohol, sodium polyacrylate dispersant, polyether dispersant, and ethylene oxide dispersant. Further, as a dispersing aid, commonly used sodium sulfate, sodium carbonate, aqueous hydrogen peroxide, boric acid and the like can be used.

The binder resin composition of the present invention is obtained by blending a polyester copolymer and a styrene-acrylic copolymer as described in detail, and each copolymer is extruded or extruded. The blending can be carried out using a mixer, but also using a suspension polymerization method, a solution polymerization method or a polycondensation method. The mixing ratio of the polyester copolymer and the styrene-acrylic copolymer is 60 to 95 for the polyester copolymer.
% By weight and 5 to 40% by weight of a styrene-acrylic copolymer, preferably 60 to 90% by weight of a polyester copolymer and a styrene-acrylic copolymer 10
-40% by weight. This is because when the content of the polyester copolymer is less than 60% by weight or when the content of the styrene-acrylic copolymer exceeds 40% by weight, the resolution and color development of the toner are poor. If the combined amount exceeds 95% by weight or the styrene-acrylic copolymer is less than 5% by weight, the positive chargeability of the toner is poor.

The binder resin of the present invention thus obtained must have a glass transition temperature of 40 to 68 ° C., a softening temperature of 80 to 125 ° C., and an acid value of 20 mg KOH / g or less. It has a glass transition temperature of 40 ° C
When the value is less than 10%, the blocking resistance of the toner is inferior.
Conversely, if the temperature exceeds 68 ° C., the fixability of the toner is inferior, and the temperature is preferably in the range of 45 to 65 ° C. When the softening temperature is lower than 80 ° C, the non-offset property of the toner is inferior. When the softening temperature is higher than 125 ° C, the fixing property of the toner is inferior, and preferably in the range of 85 to 120 ° C. Further, if the acid value exceeds 20 mgKOH / g, the moisture resistance of the toner is deteriorated.
OH / g or less.

[0027]

The present invention will be specifically described below with reference to examples. In Examples, the glass transition temperature was measured at a heating rate of 10 ° C./min by a differential calorimeter after the sample was heated to 100 ° C. and melt-quenched. The softening temperature was measured using a Shimadzu Corporation flow tester CFT-500 having a nozzle of 1.0 mmφ × 10 mm.
The temperature was measured under the condition of a load of 30 kgf and a heating rate of 3 ° C./min. The acid value was determined by a suitable method using KOH in a toluene solvent. The molecular weight was determined by gel permeation chromatography HCL-8020 (manufactured by Toso Corporation) in terms of polystyrene.

The positive charging property is as follows. 0.45 parts by weight of the toner and 10 parts by weight of the positive charging carrier are weighed in a 50 cc polyethylene container, and are weighed at about 24 ° C. in an environment at a temperature of 20 ° C. and a humidity of 60%.
After standing for a period of time, 0.2 parts by weight of a mixture obtained by stirring and mixing at a speed of about 200 rpm for about 30 minutes using a ball mill stirrer is weighed, and a blow-off charge amount measuring device (Toshiba Chemical Co., Ltd.)
B-500), and the sign was inverted to calculate the charge amount per g of toner. As a result, evaluation was made according to the following criteria.

：: Charge amount of 12 μC / g or more Δ: Charge amount of 7 μC / g or more and less than 12 μC / g ×: Charge amount of less than 7 μC / g The humidity resistance was the same as that of the positive charge, and the temperature was 35 ° C. and humidity was 85. % Was evaluated according to the following criteria based on the difference between the charge amount after being left for about 24 hours in an environment of 20% and the charge amount after being left for about 24 hours in an environment of the above temperature of 20 ° C. and humidity of 60%.

○: less than 3 μC / g △: 3 μC / g or more and less than 4 μC / g ×: 4 μC / g or more The anti-blocking property is as follows. About 10 g of the toner is placed in a 200 cc crow container and kept at about 40 ° C. After the glass container was left for about 120 hours, the state of aggregation of the toner when the glass container taken out was inverted and hit was evaluated according to the following criteria.

： １: The toner is uniformly dispersed when hit once. Δ: The toner is uniformly dispersed when hit four times. ×: The toner is not aggregated and dispersed. The positive chargeability, moisture resistance and blocking resistance are as described above. In the evaluation, if it is ○ or △, it can be used practically.

Preparation of Dispersant A A reaction vessel equipped with a stirrer, thermometer and gas inlet tube was charged with 2300 parts by weight of deionized water, 25 parts by weight of methyl methacrylate, and 75 parts by weight of 3-sodium sulfopropyl methacrylate. , N ₂ gas was blown in for about 30 minutes to expel air in the reaction system. Then, the mixture was heated from the outside with a hot water bath while stirring, and the temperature was raised to 60 ° C.
Parts by weight were added. Stirring was continued at the same temperature for about 3 hours to obtain a polymer liquid (solid content 3.3%) having a viscosity of 340 centipoise (25 ° C.) having a bluish white appearance.

Preparation Example of Polyester Copolymer Using dicarboxylic acid component and diol component shown in Table 1, 2,000 ppm of tetrakis [methylene (3,5-di-t-butyl-4 -Hydroxyhydrocinnamate)] The methane was sufficiently mixed and charged into a reaction vessel equipped with a distillation column and a stirrer, and the reaction vessel was charged with N ₂ while maintaining the stirring rotation speed at 150 rpm.
Then, the esterification reaction was carried out by raising the temperature of the reaction system to 260 ° C. over about 1 hour in a pressurized state. Then, antimony trioxide was added to the total acid component at 500 pp.
After the temperature in the reaction system was increased to 235 ° C., the inside of the reaction system was evacuated to a vacuum of 10 mmHg or less, and the diol component was flown out of the reaction system to perform a condensation polymerization reaction. Thereafter, when a predetermined softening temperature was reached, the inside of the reaction system was set to normal pressure to terminate the polycondensation reaction. Next, the temperature in the reaction system was set at 20.
After cooling to below 0 ° C., the polymer in the reaction vessel was taken out, and polyester copolymers 1 to 8 were obtained. Table 1 shows the composition and properties of the obtained polyester copolymer.

Production Example 1 of Styrene-Acrylic Copolymer 1 220 parts by weight of deionized water, 0.6 parts by weight of sodium polyacrylate (3.3% solids), 2.42 parts by weight of dispersant A,
0.55 parts by weight of sodium sulfate were mixed and charged into a reaction vessel equipped with a stirrer, a distillation column and a thermometer.
Were mixed and charged. Next, while maintaining the stirring rotation speed at 300 rpm, the polymerization initiator shown in Table 2 was added, and the temperature in the reaction system was increased to 92 ° C. to start the suspension polymerization. After performing the suspension polymerization for about 6 hours, the temperature in the reaction system is raised to about 100 ° C., and about 44 parts by weight of the remaining monomers and deionized water in the reaction system are flown out of the reaction system. The residual monomer of the polymer inside was reduced. Thereafter, the temperature in the reaction system was adjusted to about 90 ° C., and 0.5 parts by weight of sodium hydroxide was added, and alkali treatment was performed for about 30 minutes. Next, the temperature in the reaction system was cooled to room temperature, the copolymer was taken out, washed and dried to obtain styrene-acrylic copolymers 1 to 5. Table 2 shows the composition and properties of the obtained styrene-acrylic copolymer.

Preparation Example 2 of Styrene-Acrylic Copolymer Styrene-acrylic copolymer was prepared under the same conditions as in Preparation Example 2 except that the suspension polymerization temperature was 130 ° C. using the monomers and polymerization initiators shown in Table 2. Copolymers 6 and 7 were obtained. Table 2 shows the composition and properties of the obtained styrene-acrylic copolymer.

[0036]

[Table 1]

[0037]

[Table 2]

The symbols shown in Tables 1 and 2 indicate the following compounds, respectively. TPA: terephthalic acid IPA: isophthalic acid FA: fumaric acid BPP: polyoxypropylene- (2,4) -2,2
-Bis (4-hydroxyphenyl) propane BPE: polyoxyethylene- (2,4) -2,2-
Bis (4-hydroxyphenyl) propane EG: ethylene glycol NPG: neopentyl glycol St: styrene MMA: methyl methacrylate nBA: n-butyl acrylate ET: 2-ethoxyethyl methacrylate MT: 2-methoxyethyl methacrylate DE: Diethylaminoethyl methacrylate MSD: α-methylstyrene dimer BPO: benzoyl peroxide tBP: t-butylperoxybenzoate AIBN: azobisisobutyronitrile Examples 1 to 10 The polymer and the styrene-acrylic copolymer were mixed, and the mixture was melted and kneaded at a temperature 10 ° C. higher than the softening temperature of the polyester copolymer for about 30 minutes using a mixer to obtain the binder resin for toner of Examples 1 to 10. Obtained. Table 3 shows resin properties of the obtained binder resin. On the other hand, each of the obtained binder resin, 5 parts by weight of carbon black, and 3 parts by weight of a low molecular weight polypropylene wax were mixed, and the mixture was heated to a temperature lower than the softening temperature of the polyester copolymer by 10% using a mixer.
After melt-kneading at a high temperature of about 30 ° C. for about 30 minutes, the mixture was finely pulverized and classified to obtain toners of Examples 1 to 10. Table 3 shows the toner characteristics of the obtained toner.

As is clear from Table 3, Example 1 of the present invention
All of the binder resins Nos. 1 to 10 exhibited excellent positive chargeability. As for the moisture resistance, the binder resins of Examples 2 to 8 and 10 were excellent, and the binder resins of Examples 1 and 9 were slightly inferior, but at a level that did not pose any problem in practical use. Further, with respect to the blocking resistance, the binder resins of Examples 1, 2, 4 to 7, 9 and 10 were excellent, and the binder resins of Examples 3 and 8 were slightly inferior, but at a level at which there was no problem in practical use. Met.

Comparative Examples 1 to 9 Comparative Examples 1 to 10 were carried out under the same conditions as in Examples 1 to 10, except that the polyester copolymer and the styrene-acrylic copolymer were mixed in the types and amounts shown in Table 4. ~ 9 binder resins and toners were obtained. Table 4 shows resin properties of the obtained binder resin and toner properties of the obtained toner. As is clear from Table 4, Comparative Examples 1, 2 and 4
The binder resins Nos. 7 to 7 were inferior in toner properties and were not at a practically usable level. The binder resins of Comparative Examples 3, 8 and 9 were at usable levels with respect to positive chargeability, moisture resistance and blocking resistance, but the binder resin of Comparative Example 3 had a melt fluidity and smoothness as a toner. The binder resin of Comparative Example 8 was inferior in fixability as a toner, and the binder resin of Comparative Example 9 was inferior in cloudiness, was not transparent, and was inferior in color developability as a toner.

[0041]

[Table 3]

[0042]

[Table 4]

[0043]

The binder resin composition for toner of the present invention has good moisture resistance and excellent charge stability by using a polyester copolymer and a specific styrene-acrylic copolymer having a strong positive charge. In addition, it is possible to provide a full-color toner having excellent positive chargeability without environmental pollution.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-56-69643 (JP, A) JP-A-63-127254 (JP, A) JP-A-63-68851 (JP, A) (58) Field (Int.Cl. ⁷ , DB name) G03G 9/08

Claims (3)

(57) [Claims] 1. A polyester copolymer comprising 60 to 95% by weight of an acid component composed of a dicarboxylic acid and a diol component containing a bisphenol A type aromatic diol, and an acrylate component and / or a methacrylate ester having an ether group. A styrene-acrylic copolymer containing 1 to 40% by weight of a component,
Glass transition temperature 40-68 ° C, softening temperature 80-12
A binder resin composition for a positively chargeable toner, which has an acid value of 5 mgKOH / g or less at 5 ° C. 2. The polyester copolymer has a glass transition temperature of 40 to 68 ° C., a softening temperature of 80 to 125 ° C., an acid value of 20 mg KOH / g or less, and a weight average molecular weight of 30.
2. The binder resin composition for a positively chargeable toner according to claim 1, wherein the binder resin composition has a molecular weight of from 0.000 to 20,000. 3. A styrene-acrylic copolymer having a glass transition temperature of 40 to 68 ° C. and a softening temperature of 80 to 125.
2. The binder resin composition for a positively chargeable toner according to claim 1, wherein the binder resin composition has an acid value of 20 mgKOH / g or less and a weight average molecular weight of 3,000 to 30,000.