JPH06138702A - Binder resin composition for positively charged toner - Google Patents

Abstract

PURPOSE:To provide a binder resin compsn. suitable for a toner being good in fixing property, nonoffset property, blocking resistance and moisture resistance and having an excellent positively electrification property. CONSTITUTION:The binder resin compsn. for a positively charged toner consists of 60-95wt.% polyester copolymer contg. multyvalent carboxylic acid of >=3 valent and 5-40wt.% styrene-acrylate copolymer contg. 1-40wt.% acrylate ester component and/or methacrylate ester component having an ether linkage. The composition has glass transition temp. of 40-68 deg.C, softening temp. of 95-165 deg.C and acid number of <=30mgKOH/g.

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 full-color toners used in electrophotography, electrostatic printing, etc., which is excellent in non-offset property, fixability and blocking resistance. The present invention provides a binder resin composition for toner, which exhibits excellent positive chargeability and does not cause environmental pollution.

[0002]

2. Description of the Related Art Toners and binder resins for toners used in electrophotographic copying machines, printers, etc. are required to have the following properties. Blocking resistance and the like are listed, and secondly, charging characteristics that affect image formation are listed.

Regarding the fixability, it is important to lower the fixing temperature due to the increase in printing speed, and as the binder resin for toner, one having good melt fluidity is used.
Regarding the non-offset property, it is important that the toner does not offset to the roller even in a relatively high temperature region, and as the binder resin for toner, one having a high elastic force is used. Regarding blocking resistance,
It is important that the toner does not cause blocking even when the toner is stored at a high temperature, and a binder resin for a toner having a relatively high glass transition temperature is used.

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, it is necessary to determine the charge amount of the toner and the binder resin for the toner by the photoconductor such as a copying machine or a printer.As the binder resin for the toner, the charge amount is controlled by the monomer used and the molecular structure. It 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, and as a binder resin for toner, this can be prevented by the resin manufacturing method. It was

The charging of the toner and the binder resin for the toner includes a negative charging type and a positive charging type. For a negative charging type toner, the charge amount is adjusted by a negative charging type resin and a negative charging type charge control agent. To be done. Also in the positively chargeable toner, the positively chargeable resin and the charge control agent are used similarly to the negatively chargeable toner, but the control of the charge amount of the positively chargeable toner has various problems. Therefore, various studies have been conducted on a binder resin for positively charged toner.

As a binder resin for positively chargeable toner, a polyester copolymer excellent in fixability and high resolution is used, and use of various positively chargeable monomers has been studied for the purpose of improving its positive charge characteristic. However, it has been difficult to improve the positive charging property because the ester bond exhibits a very strong negative charge. Therefore, a method of improving the positive charging property of the polyester copolymer by blending a styrene-acrylic copolymer using a monomer containing an amino group or an amide group has been carried out.

[0007]

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

[0008]

In view of such circumstances, the inventors of the present invention have made earnest studies on resins for positively chargeable toner, and as a result, have found that a specific polyester copolymer excellent in low-temperature fixing property and non-offset property is obtained. It was discovered that a binder resin for toner having an excellent positive charging property can be obtained by blending with a specific styrene-acrylic copolymer having an excellent positive charging property. That is, the binder resin composition for a positively chargeable toner of the present invention is a polyester copolymer 60 containing a trivalent or higher polycarboxylic acid.
˜95% by weight, and 1 to acrylate component and / or methacrylic acid ester component having an ether group.
Styrene-acrylic copolymer containing 40% by weight 5
40% by weight and having a glass transition temperature of 40 to 68
℃, softening temperature 95-165 ℃, acid value 30mgKOH
/ G or less.

The polyester copolymer used in the present invention is a cross-linked polyester copolymer containing a polycarboxylic acid having a valence of 3 or more, and an acid component composed of a polycarboxylic acid having a valence of 3 or more and a dicarboxylic acid. And a diol component composed of an aromatic diol and an aliphatic diol. Examples of the trivalent or more polyvalent carboxylic acid used in the present invention include trimellitic acid, pyromellitic acid, 1,2,4 cyclohexanetricarboxylic acid, 2,
Examples thereof include 5,7 naphthalene tricarboxylic acid, 1,2,4 naphthalene tricarboxylic acid, 1,2,5 hexane tricarboxylic acid, 1,2,7,8 octane tetracarboxylic acid, and acid anhydrides thereof. Among them, trimellitic acid or its acid anhydride is preferable. These trivalent or higher polycarboxylic acids are contained in the range of 2 to 50 mol%, preferably 5 to 45 mol% based on the total acid components. This is because the toner using the polyester copolymer having a trivalent or higher polyvalent carboxylic acid in this range is excellent in non-offset properties.

In the present invention, the dicarboxylic acid used as the acid component other than the trivalent or higher polyvalent carboxylic acid is
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, sebacic acid, malonic acid, linolein Acids or their acid anhydrides may be mentioned, and these polyvalent carboxylic acids may be used alone or
A combination of two or more species can be used. Of these, terephthalic acid, isophthalic acid, and alkenylsuccinic acid are preferable. These dicarboxylic acids contain 50 to 9 relative to the total acid components.
It is preferably contained in the range of 8 mol%, and more preferably in the range of 55 to 95 mol%.

Examples of the aromatic diol used as the diol component constituting the polyester copolymer include bisphenol A-type aromatic diols such as 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 can be mentioned, and these bisphenol A type aromatic diols can be used alone or in combination of two or more kinds. Among them, polyoxypropylene- (2,4) -2,
2-bis (4-hydroxyphenyl) propane and polyoxyethylene- (2,4) -2,2-bis (4-hydroxyphenyl) propane are preferred. These aromatic diols are preferably contained in the range of 10 to 90 mol%, more preferably 20 to 80 mol%, based on the total acid components. This is because the fixability of the toner using the polyester copolymer containing an aromatic diol in this range is good.

In the present invention, as the aliphatic diol used as a diol component other than the aromatic diol,
For example, ethylene glycol, diethylene glycol,
Triethylene glycol, polyethylene glycol, propylene glycol, butanediol, neopentyl glycol, cyclohexanedimethanol and the like,
These aliphatic diols can be used alone or in combination of two or more. Among them, ethylene glycol and neopentyl glycol are particularly preferable. These aliphatic diols are preferably contained in the range of 10 to 90 mol% with respect to the total acid component, more preferably 20.
Is in the range of ˜80 mol%.

The polyester copolymer used in the present invention preferably has a glass transition temperature of 40 to 68 ° C., a softening temperature of 100 to 165 ° C., and an acid value of 30 mgKOH / g or less. It has a glass transition temperature of 40.
This is because if the temperature is lower than ℃, the blocking resistance of the toner tends to be inferior, and if it exceeds 68 ℃, the fixing property of the toner tends to be impaired, and more preferably 45 to 65 ℃.
Is the range. Further, when the softening temperature is less than 100 ° C, the non-offset property of the toner tends to be poor, and when it exceeds 165 ° C, the sharp melt property of the toner tends to be poor, and more preferably in the range of 105 to 160 ° C. Is. Further, when the acid value exceeds 30 mgKOH / g, the moisture resistance of the toner tends to be poor, and more preferably in the range of 25 mgKOH / g or less.

As a method for producing the polyester copolymer, a usual polyester polycondensation method is used.
Considering the molar ratio of the total acid component and the total diol component in accordance with the concentration of the polycarboxylic acid having a valence of 3 or more, a method in which the condensation is carried out after the direct esterification method or the transesterification method is preferable. In the production, a polymerization catalyst such as titanium butoxide, dibutyltin oxide, tin acetate, zinc acetate, tin disulfide, antimony trioxide, germanium dioxide can be used, but among them, dibutyltin oxide, antimony trioxide, zinc acetate. Is preferred.

Examples of the acrylate ester component or methacrylic acid ester component having an ether group used in the present invention include 2-ethoxyethyl acrylate,
Examples thereof include 2-methoxyethyl acrylate, 2-budoxyethyl acrylate, 2-ethoxyethyl methacrylate, 2-methoxyethyl methacrylate, 2-budoxyethyl methacrylate, and the like, of which 2-ethoxyethyl methacrylate is particularly preferable. In the present invention, these acrylic acid ester components or methacrylic acid ester components having an ether group may be used alone or in combination of two or more.

The amount of the acrylic acid ester component or methacrylic acid ester component having an ether group used is required to be 1 to 40% by weight, preferably 5 to 30% by weight, based on the total polymer components. . this is,
If the amount used is less than 1% by weight, it is difficult to obtain a satisfactory charge amount due to poor positive charging property. On the contrary, if the amount used exceeds 40% by weight, the glass transition temperature of the toner becomes low and the blocking resistance is increased. This is because the sex is inferior.

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

Examples of the styrene component used in the styrene-acrylic copolymer of the present invention include styrene and
o-methylstyrene, m-methylstyrene, p-methylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, 3,4-dichlorostyrene,
p-ethylstyrene, 2,4-dimethylstyrene, p-
n-butyl styrene, p-tert butyl styrene, p
-N-hexyl styrene, pn-octyl styrene,
pn-nonylstyrene, pn-decylstyrene, p
Examples include -n-dodecyl styrene and α-methyl styrene. Among them, styrene, p-methylstyrene and α-methylstyrene are particularly preferable. By using such a styrene component, the moisture resistance of the toner can be improved.

Further, the acrylic acid ester component or the methacrylic acid ester component is a component other than the acrylic acid ester component or the methacrylic acid ester component having an ether group. As the acrylic ester 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 them, n-butyl acrylate and 2-ethylhexyl acrylate are particularly preferable. Examples of the methacrylic acid ester component include 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, dimethylaminoethyl methacrylate, and the like, with methacrylic acid, methyl methacrylate, and n-butyl methacrylate being particularly preferred. Such an acrylic acid ester component or a methacrylic acid ester component can improve the positive chargeability of the toner,
It is easy to obtain a synergistic effect with the acrylic ester component or methacrylic ester component having an ether group.

Further, as the unsaturated dibasic acid component, for example, maleic acid, butyl maleate, methyl maleate, dimethyl maleate, fumaric acid, butyl fumarate,
Examples thereof include dibutyl fumarate, diisobutyl fumarate, dimethyl fumarate, diethyl fumarate and the like, and among them, dibutyl fumarate is particularly preferable. By using such an unsaturated dibasic acid component, the positive chargeability of the toner can be improved. In the present invention, a component other than the above-mentioned styrene component, acrylic acid ester component, methacrylic acid ester component and unsaturated dibasic acid component should be used as long as it has a double bond capable of radical polymerization. You can 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 or an unsaturated polyester may be performed.

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

The one having a cross-linked structure is one containing 1 to 75% of a component (gel fraction) insoluble in a solvent such as tetrahydrofuran or chloroform. The cross-linking structure-providing monomer is not particularly limited as long as it forms a cross-linking structure in the reaction, and examples thereof include 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, tetramethylolmethane triacrylate, tetramethylolmethane tetraacrylate, bisphenol A Examples thereof include derivative-type acrylates and the like, and those in which acrylic acid of these compounds is changed to methacrylic acid.

The non-crosslinked structure having one or more peaks in each of the high molecular weight region and the low molecular weight region in the molecular weight distribution has a molecular weight of 3 × 10 ⁵ in the molecular weight distribution.
Has one or more peaks in the ultra high molecular weight 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. Further, the binder resin having one or more peaks in the molecular weight distribution is a binder resin having a non-crosslinking structure having one or more peaks in the molecular weight distribution, in addition to the above-mentioned non-crosslinking structure.

The styrene-acrylic copolymer used in the present invention has a glass transition temperature of 40 ° C. or higher, a softening temperature of 80 to 140 ° C., an acid value of 20 mgKOH / g or less, and a weight average molecular weight of 3,000 to 80,000. Those having a number average molecular weight of 1,000 to 45,000 are preferable. If the glass transition temperature is less than 40 ° C., the blocking resistance of the toner tends to be poor, and more preferably 50 to 50.
It is in the range of 65 ° C. If the softening temperature is lower than 80 ° C., the blocking resistance of the toner tends to be poor, and conversely, 14
This is because if the temperature exceeds 0 ° C., the fixability tends to deteriorate regardless of the softening temperature of the toner, and more preferably 90 to 135.
It is in the range of ° C. Further, when the acid value exceeds 20 mgKOH / g, the moisture resistance of the toner tends to be poor,
More preferably, it is in the range of 15 mgKOH / g or less. By controlling the polymerization average molecular weight and the number average molecular weight in this range, excellent positive chargeability can be exhibited, and when the weight average molecular weight is less than 3000 or the number average molecular weight is less than 1000, the glass transition temperature is If the weight average molecular weight exceeds 80,000 or the number average molecular weight exceeds 45,000, the positive charging property tends to be poor, and the weight average molecular weight is more preferable. Fifty
00-70000, number average molecular weight 2000-4000
The range is 0.

Examples of the method for producing the styrene-acrylic copolymer of the present invention include bulk polymerization, suspension polymerization, emulsion polymerization, solution polymerization and the like, and these polymerization methods may be used in combination of two or more. Good. These manufacturing 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 in ordinary radical polymerization, but in order to achieve the object of the present invention, a peroxide-based polymerization initiation Agents are particularly preferred. Examples of peroxide-based polymerization initiators include benzoyl peroxide and t-
Butyl peroxyisobutyrate, t-butyl peroxy 2-ethylhexanoate, t-butyl peroxy benzoate, t-butyl peroxy isopropyl carbonate, di-t-butyl diperoxy isophthalate, etc. are mentioned. They may be used alone or in combination of two or more. Among them, benzoyl peroxide, t
-Butyl peroxybenzoate is particularly preferred. Furthermore, 2,2'-azobis (2-methylbutyronitrile), 2,2'-azobis (2,4'-dimethylvaleronitrile), 1,1-bis (t-butylperoxy)
3,3,5-trimethylcyclohexane, 1,1-azobis (cyclohexane-1-carbonitrile), 2,
Even if an azo-based polymerization initiator such as 2'-azobis (2,4,4-trimethylpentane) is used, the positive charging effect 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 emulsifiers and dispersants include polyvinyl alcohol, sodium polyacrylate-based dispersants, polyether-based dispersants, and ethylene oxide-based dispersants. Further, as the dispersion aid, commonly used sodium sulfate, sodium carbonate, aqueous hydrogen peroxide, boric acid, etc. can be used.

The binder resin composition of the present invention is obtained by blending the polyester copolymer and the styrene-acrylic copolymer as described in detail, and the respective copolymers are extruded by an extruder or Blending can be performed using a mixer, but it is also possible to blend 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 styrene-acrylic copolymer, preferably 60 to 90% by weight of polyester copolymer and 10 of styrene-acrylic copolymer.
-40% by weight. This is because when the content of the polyester copolymer is less than 60% by weight or the content of the styrene-acrylic copolymer exceeds 40% by weight, the non-offset property of the toner is inferior, and conversely the polyester copolymer is used. Is more than 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 95 to 165 ° C., and an acid value of 30 mgKOH / g or less. It has a glass transition temperature of 40 ° C.
If it is less than 1, the blocking resistance of the toner is poor,
On the contrary, when the temperature exceeds 68 ° C, the fixing property of the toner is deteriorated, and the temperature is preferably in the range of 45 to 65 ° C. Further, when the softening temperature is lower than 95 ° C, the non-offset property of the toner is inferior, and when it exceeds 165 ° C, the fixing property of the toner is inferior, and the range of 100 to 160 ° C is preferable. Further, when the acid value exceeds 30 mgKOH / g, the moisture resistance of the toner is inferior, and preferably 25 mgK
It is in the range of OH / g or less.

[0029]

EXAMPLES The present invention will be specifically described below with reference to examples. In the examples, the glass transition temperature was measured at a temperature rising rate of 10 ° C./min by a differential calorimeter after the sample was heated to 100 ° C. and melt-quenched. As for the softening temperature, a Shimadzu Corporation flow tester CFT-500 having a nozzle of 1.0 mmφ × 10 mm was used.
The temperature was measured under the conditions of a load of 30 Kgf and a temperature rising rate of 3 ° C./min, and the temperature when the sample flowed out ½ was defined as the softening temperature. The acid value was determined by a titration method using KOH in a toluene solvent. The molecular weight was calculated by polystyrene conversion using gel permeation chromatography HCL-8020 (manufactured by Toso Co., Ltd.).

The fixing property was evaluated according to the following criteria by using a copying machine in which the speed and temperature of the fixing roller can be freely changed, setting the speed of the fixing roller to 350 mm / sec, and measuring the fixing temperature. ◯: Less than 150 ° C. Δ: 150 ° C. or more and less than 171 ° C. ×: 171 ° C. or more For non-offset properties, use a copying machine in which the speed and temperature of the fixing roller can be freely changed,
The offset generation temperature was set at 50 mm / sec, and evaluated according to the following criteria.

◯: 210 ° C. or more Δ: 190 ° C. or more and less than 210 ° C. ×: less than 190 ° C. For positive charging property, 0.45 part by weight of toner and 10 parts by weight of positive charging carrier are weighed in a polyethylene container of 50 cc,
After leaving it for about 24 hours in an environment of a temperature of 20 ° C and a humidity of 60%, use a ball mill stirrer for about 30 rpm at a speed of about 200 rpm.
0.2 parts by weight of the mixture that was stirred and mixed for 1 minute was weighed, and a blow-off charge amount measuring device (TB-500 manufactured by Toshiba Chemical Co.)
Was used to measure the amount of charge, and the sign was reversed to calculate the amount of charge per 1 g of toner. As a result, it was evaluated 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 Moisture resistance was the same as that of positive charge property at a temperature of 35 ° C. and a humidity of 85. % And the amount of charge after being left for about 24 hours in the environment of 20 ° C. and 60% of humidity and the difference between the amount of charge after standing for about 24 hours in the environment were evaluated according to the following criteria.

◯: Less than 3 μC / g Δ: 3 μC / g or more and less than 4 μC / g ×: 4 μC / g or more As for blocking resistance, about 10 g of toner is put in a 200 cc glass container and kept at about 40 ° C. in a hot air dryer. After the glass container was placed in a container and left for about 120 hours, the aggregation state of the toner when the taken out glass container was upside down and beaten was evaluated according to the following criteria.

◯: Toner uniformly disperses when tapped once Δ: Toner uniformly disperses when tapped 4 times ×: Toner does not aggregate and disperse Note that the above-mentioned positive charging property, moisture resistance and blocking resistance In the evaluation, if it is ◯ or Δ, it can be practically used.

Manufacturing Method of Dispersant A A reactor equipped with a stirrer, a thermometer and a 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 for about 30 minutes to expel the air in the reaction system. Then, while stirring, the mixture is heated from the outside in a hot water bath to raise the temperature to 60 ° C., and ammonium persulfate 0.5
Parts by weight were added. Stirring was continued for about 3 hours at the same temperature to obtain a polymer liquid (solid content: 3.3%) having a viscosity of 340 centipoise (25 ° C.) and a bluish white appearance.

Production Example of Polyester Copolymer The acid component and the diol component shown in Table 1 were placed in a reaction vessel equipped with a distillation column and a stirrer, and the stirring speed was 150 r.
While maintaining the pressure at pm, the reaction vessel was pressurized with N ₂ and the temperature of the reaction system was raised to 260 ° C. over about 1 hour to carry out the esterification reaction. Next, after adding 500 ppm of antimony trioxide to the total acid component and setting the temperature in the reaction system to 245 ° C., the reaction system was evacuated to a vacuum state of 10 mmHg or less to allow the diol component to flow out from the reaction system to carry out the polycondensation reaction. went. When the viscosity of the polymer suddenly rises and gelation reaction starts, the vacuum degree in the reaction system is set to 50 mmH.
It was set to g to mitigate the increase in viscosity due to gelation. After that, the viscosity of the polymer in the reaction system gradually starts to increase again, while the gelation reaction is controlled by gradually lowering the vacuum degree in the reaction system, and when the desired viscosity is reached, the reaction The system was returned to normal pressure to complete the condensation reaction. Then, the temperature in the reaction system was cooled to less than 200 ° C. and the polymer in the reaction vessel was taken out to obtain polyester copolymers 1 to 7. The composition and properties of the obtained polyester copolymer are shown in Table 1.

Production Example 1 of Styrene-Acrylic Copolymer 220 parts by weight of deionized water, 0.6 parts by weight of sodium polyacrylate (solid content 3.3%), 2.42 parts by weight of dispersant A,
0.55 parts by weight of sodium sulfate are mixed and charged into a reaction vessel equipped with a stirrer, a distillation column and a thermometer, and then Table 2
The monomers shown in 1 above were mixed and added. 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 raised to 92 ° C. to start suspension polymerization. After carrying out 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 residual monomer and deionized water in the reaction system flow out of the reaction system. The residual monomer of the polymer inside was reduced. Then, the temperature in the reaction system was adjusted to about 90 ° C., 0.5 part 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. The composition and characteristics of the obtained styrene-acrylic copolymer are shown in Table 2.

Production Example 2 of Styrene-Acrylic Copolymer A styrene-acrylic copolymer was produced under the same conditions as in Production Example 2 except that the suspension polymerization temperature was 130 ° C. using the monomers and the polymerization initiators shown in Table 2. Copolymers 6 and 7 were obtained. The composition and characteristics of the obtained styrene-acrylic copolymer are shown in Table 2.

[0039]

[Table 1]

[0040]

[Table 2]

The symbols shown in Tables 1 and 2 represent the following compounds, respectively. TPA: terephthalic acid IPA: isophthalic acid TMA: trimellitic anhydride AKA: alkenyl succinic 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 8 Polyester copolymers with the types and blending amounts shown in Table 3 The polymer and the styrene-acrylic copolymer were mixed, melt-kneaded at a temperature 10 ° C. higher than the softening temperature of the polyester copolymer for about 30 minutes using a mixer, and then finely pulverized and classified to obtain an example. 1-10 toner binder To give the gin. The resin properties of the obtained binder resin are shown in Table 3.
On the other hand, each of the obtained binder resins, 5 parts by weight of carbon black and 3 parts by weight of low molecular weight polypropylene wax are mixed and melted at a temperature 10 ° C higher than the softening temperature of the polyester copolymer for about 30 minutes using a mixer. After kneading, finely pulverized and classified to obtain a toner. The toner characteristics of the obtained toner are shown in Table 3.

As is clear from Table 3, Example 1 of the present invention
In Nos. 8 to 8, the toners of Examples 1 to 4, 7 and 8 were excellent in fixing property, and the toners of Examples 5 and 6 were slightly inferior, but they were at a level where there was no problem in practical use. With respect to the non-offset property, the toners of Examples 1 to 3 and 7 were excellent, and the toners of Examples 4 to 6 and 8 were slightly inferior, but they were at a level having no problem in practical use. For blocking resistance, see Examples 2, 3, 5, 6, and 8
The toner of Example 1 was excellent, and the toners of Examples 1, 4 and 7 were slightly inferior, but they were at a level having no problem in practical use. Regarding the positive chargeability, the toners of Examples 1 to 4, 7 and 8 were superior, and the binder resins of Examples 5 and 6 were slightly inferior, but were at a level where there was no problem in practical use. Regarding the moisture resistance, the toners of Examples 2 to 8 were excellent, and the toner of Example 1 was slightly inferior, but it was at a level where there was no problem in practical use.

Comparative Examples 1 to 9 Comparative Examples 1 to 1 were conducted under the same conditions as in Examples 1 to 8 except that the polyester copolymer and the styrene-acrylic copolymer were mixed in the types and amounts shown in Table 4. Binder resin for toner and toner of No. 9 were obtained. The resin properties of the obtained binder resin and the toner properties of the toner are shown in Table 4. As is clear from Table 4, the toners of Comparative Examples 1 to 9 are
All of them were inferior in toner characteristics and were not practically usable.

[0044]

[Table 3]

[0045]

[Table 4]

[0046]

The binder resin composition for a toner of the present invention uses a polyester copolymer and a specific styrene-acrylic copolymer having a strong positive charging property to fix the toner, prevent the offset, and block the toner. Further, it is possible to provide a toner having good moisture resistance and excellent positive chargeability.

Claims (4)

[Claims] 1. Styrene containing 60 to 95% by weight of a polyester copolymer containing a trivalent or higher polyvalent carboxylic acid and 1 to 40% by weight of an acrylate ester component and / or a methacrylic acid ester component having an ether group. A positively chargeable toner comprising an acrylic copolymer of 5 to 40% by weight, a glass transition temperature of 40 to 68 ° C., a softening temperature of 95 to 165 ° C., and an acid value of 30 mgKOH / g or less. Binder resin composition. 2. A polyester copolymer comprising an acid component composed of 2 to 50 mol% of a trivalent or higher polyvalent carboxylic acid and 50 to 98 mol% of a dicarboxylic acid, and 10 to 90 mol% of an aromatic diol. A binder resin composition for a positively chargeable toner according to claim 1, which comprises a diol component consisting of 10 to 90 mol% of an aliphatic diol. 3. The polyester copolymer has a glass transition temperature of 40 to 68 ° C., a softening temperature of 100 to 165 ° C., an acid value of 30 mgKOH / g or less, and a weight average molecular weight of 3.
The binder resin composition for a positively chargeable toner according to claim 1, wherein the binder resin composition is 000 to 20,000. 4. The styrene-acrylic copolymer has a glass transition temperature of 40 ° C. or higher and a softening temperature of 80 to 140 ° C.
The acid value is 20 mgKOH / g or less, the weight average molecular weight is 3000 to 80,000, and the number average molecular weight is 1000 to 4.
The binder resin composition for a positively chargeable toner according to claim 1, wherein the binder resin composition is 5,000.