JPH05323662A - Binder resin for positively chargeable toner - Google Patents

Abstract

PURPOSE:To obtain a binder resin for a toner excellent in positive chargeability as well as fixability, anti-offsetting property and blocking resistance, ensuring a stable amt. of positive charges and causing no environmental pollution. CONSTITUTION:This binder resin for a positively chargeable toner is a polymer contg. 1-40wt.% acrylic ester and/or methacrylic ester having an ether group and >=1wt.% p-methylstyrene and has 40-68 deg.C glass transition temp., 80-140 deg.C softening temp., <=20mg KOH/g acid value, 3,000-80,000wt. average mol.wt. and 1,000-45,000 number average mol.wt.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is a toner which is excellent in non-offset property, fixing property and blocking resistance used in electrophotographic method, electrostatic printing method, etc. A binder resin for use is provided.

[0002]

2. Description of the Related Art Toners and binder resins for toners used in electrophotographic copying machines, printers and the like 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 of utmost importance to lower the fixing temperature due to the increase in the printing speed, and as the binder resin for toner, one having good melt fluidity has been 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 has been used. Regarding blocking resistance, it is important that the toner does not block even if the temperature during storage of the toner is high, and as the binder resin for toner, one having a relatively high glass transition temperature (Tg) has been used.

Furthermore, the charging characteristics that have the greatest influence on image formation are important, and the problem of charge amount and charge stability (moisture resistance)
It is roughly divided into. Regarding the problem of 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, and the charge amount of the binder resin for the toner depends on the monomer and the molecular structure used. I've been in control. 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 is prevented by the resin manufacturing method. I've been

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. Has been done. Further, the positively chargeable toner also uses a positively chargeable resin and a charge control agent like the negatively chargeable toner, but the control of the charge amount of the positively chargeable toner has various problems, Various studies have been conducted on a positively chargeable binder resin for toner.

[0006]

In order to obtain a positively chargeable binder resin, an amine type or amide type monomer is generally used. However, when an amine type or amide type monomer is used, Requires that an azo-based polymerization initiator be used in the synthesis of the binder resin, and the reaction conditions and characteristic values of the resin may differ when compared with the case where a peroxide-based polymerization initiator is used. However, there is a problem in that the moisture resistance becomes poor and the charging stability becomes poor, and the thermal characteristics of the toner are different, resulting in poor toner color development. Furthermore, 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.

SUMMARY OF THE INVENTION An object of the present invention is to provide a binder resin for toner which is excellent in non-offset property, fixing property and anti-blocking property and has excellent positive charging property without environmental pollution.

[0008]

In view of such a situation, the inventors of the present invention have made earnest studies on the relationship between the molecular weight of the binder resin and the positive chargeability of the resin for toner, and as a result, as a result of containing a specific monomer, By controlling the molecular weight, a positive chargeability having an excellent charge level can be stably obtained, and the binder resin for a toner of the present invention having no environmental pollution was found. That is,
The binder resin for a positively chargeable toner of the present invention contains an acrylic ester component and / or a methacrylic ester component having an ether group in an amount of 1 to 40 in all polymer components.
%, P-methylstyrene component is contained in the total polymer in an amount of 1% by weight or more, glass transition temperature is 40 to 68 ° C., softening temperature is 80 to 180 ° C., acid value is 20 mgKOH / g or less,
The weight average molecular weight is 3,000 to 80,000 and the number average molecular weight is 1,000 to 45,000.

Examples of the acrylate ester component or methacrylate ester component having an ether group used in the present invention include 2-ethoxyethyl acrylate,
2-methoxyethyl acrylate, 2-budoxyethyl acrylate, 2-ethoxyethyl methacrylate, 2-methoxyethyl methacrylate, 2-budoxyethyl methacrylate and the like can be mentioned, with 2-ethoxyethyl methacrylate being particularly preferred. 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 because when the amount used is less than 1% by weight, it is difficult to obtain a satisfactory charge amount due to poor positive chargeability.
This is because if the amount used exceeds 40% by weight, the glass transition temperature of the toner becomes low and the blocking resistance becomes poor.

The binder resin of the present invention contains p
-A positive chargeability can be improved by containing a methylstyrene component, and the amount thereof used is 1% by weight or more, preferably 1 to 30% by weight, more preferably 5 to 25%, based on the total polymer components. It is in the range of% by weight. This is because if the p-methylstyrene component is less than 1% by weight, the positive charging property is not improved.

In the binder resin of the present invention, the weight average molecular weight is 3,000 to 80,000 and the number average molecular weight is 1,000 to 45,000, which is the weight, and the weight average molecular weight is controlled in this range. As a result, excellent positive chargeability can be obtained. This is because when the weight average molecular weight is less than 3,000, the glass transition temperature tends to be low and the blocking resistance is poor, and conversely, when it exceeds 80,000, the positive charging property is poor, which is preferable. Has a weight average molecular weight of 5,000 to 7
It is in the range of 10,000. The number average molecular weight is 1,0
This is because if it is less than 00, the glass transition temperature tends to be low and the blocking resistance is poor, and conversely 45,0.
This is because when it exceeds 00, the positive chargeability is poor, and the number average molecular weight is preferably in the range of 2,000 to 40,000.

In the binder resin of the present invention, the glass transition temperature needs to be in the range of 40 to 68 ° C, preferably 50 to 65 ° C. This is because if the glass transition temperature is lower than 40 ° C., the blocking resistance of the toner is poor, and if it exceeds 68 ° C., the fixing property of the toner is poor. Further, in the binder resin of the present invention, the softening temperature needs to be in the range of 80 to 140 ° C, preferably 90 to 135 ° C. This is because when the softening temperature is lower than 80 ° C., the non-offset property of the toner is poor, and when it exceeds 140 ° C., the fixing property of the toner is poor. Further, the binder resin of the present invention has an acid value of 20 mgKOH /
It must be g or less, preferably 15 mgK
It is in the range of OH / g or less. This has an acid value of 20 mgK
This is because if the OH / g is exceeded, the moisture resistance of the toner will be poor.

Other than the acrylic ester component or methacrylic acid ester component having the above ether group and the p-methylstyrene component constituting the binder resin of the present invention, a styrene component, an acrylic acid ester component, and a methacrylic acid ester component are used. Alternatively, an unsaturated dibasic acid component or the like may be used. 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 60 to 9 in all polymer components.
It is used in the range of 9% by weight, preferably 70 to 95% by weight. 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 A combination with an ester component and an unsaturated dibasic acid component is particularly preferable.

The styrene component is a styrene component other than p-methylstyrene, such as styrene, O-methylstyrene, m-methylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene,
3,4-dichlorostyrene, p-ethylstyrene, 2,
4-dimethylstyrene, pn-butylstyrene, p-
tert-butyl styrene, pn-hexyl styrene,
pn-octylstyrene, pn-nonylstyrene,
pn-decylstyrene, pn-dodecylstyrene,
Examples include α-methylstyrene. 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.

The acrylic ester component or methacrylic ester component is a component other than the acrylic ester component or methacrylic ester component having an ether group. Examples of the acrylate component include acrylic acid, ethyl acrylate, methyl acrylate, n-butyl acrylate, isobutyl acrylate, propyl acrylate, 2-ethylhexyl acrylate, 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. Among them, methacrylic acid, methyl methacrylate, and n-butyl methacrylate are particularly preferable. Such an acrylic acid ester component or a methacrylic acid ester component can improve the positive chargeability of the toner, and can easily obtain a synergistic effect with the acrylic acid ester component or the methacrylic acid ester component having an ether group. is there.

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, and diethyl fumarate, 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, other than the above-mentioned styrene component, acrylic acid ester component, methacrylic acid ester component, unsaturated dibasic acid component, any component having a double bond capable of radical polymerization should be used. 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 molecular weight modifier in the binder resin of the present invention. Examples of the chain transfer agent component include α-methylstyrene dimer, n-dodecyl mercaptan, Examples thereof include thioglycolic acid ester and n-octyl mercaptan, and among them, α-methylstyrene dimer and thioglycolic acid ester are particularly preferable. The binder resin of the present invention can be used alone as a binder resin for toner, but it is usually used as a binder resin such as styrene / acrylic type, styrene / butadiene type, polyester type, or a mixture thereof. It can also be used in combination. Examples of the method for producing the binder resin of the present invention include bulk polymerization, suspension polymerization, emulsion polymerization, solution polymerization and the like, and two or more of these polymerization methods may be combined. These manufacturing methods are
It is 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 can be used in ordinary radical polymerization, but in order to achieve the object of the present invention, a peroxide type initiator is used. The polymerization initiator of is particularly preferable. Examples of peroxide-based polymerization initiators include benzoyl peroxide, t-butylperoxyisobutyrate, t-butylperoxy 2-ethylhexanoate, t-butylperoxybenzoate and t-butylperoxy. Examples thereof include isopropyl carbonate and di-t-butyldiperoxyisophthalate, which may be used alone or in combination of two or more kinds.
Among them, benzoyl peroxide and t-butyl peroxybenzoate are particularly preferable. Furthermore, 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-
The effect of positive charging can also be obtained by using an azo-based polymerization initiator such as trimethylpentane).

When the binder resin of the present invention is produced by emulsion polymerization or suspension polymerization, ordinary emulsifiers and dispersants can be used. As the emulsifier and the dispersant, polyvinyl alcohol, a sodium polyacrylate-based dispersant,
Examples include polyether-based dispersants and ethylene oxide-based dispersants. Furthermore, as a dispersion aid, sodium sulfate, sodium carbonate, hydrogen peroxide solution, which are usually used,
Boric acid or the like can be used.

[0020]

EXAMPLES The present invention will be specifically described below with reference to examples. In the examples, the glass transition temperature (Tg) was determined by heating the sample to 100 ° C. and melt quenching,
It was measured by a differential calorimeter at a temperature rising rate of 10 ° C./min. The softening temperature was measured under the conditions of a load of 30 Kgf and a heating rate of 3 ° C./min using a flow tester CFT-500 manufactured by Shimadzu Corporation having a nozzle of 1.0 mmφ × 10 mm, and 1/2 of the sample flowed out. The temperature at that time 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 determined by polystyrene conversion using gel permeation chromatography HCL-8020 (manufactured by Toso Corporation). The positive charging property is obtained by weighing 0.45 parts by weight of toner and 10 parts by weight of a carrier for positive charging in a polyethylene container having a capacity of 50 cc and leaving the container in an environment of a temperature of 20 ° C. and a humidity of 60% for about 24 hours, and then using a ball mill stirrer. About 20
Mixture 0.2 with stirring at a speed of 0 rpm for about 30 minutes
By weighing parts, the charge amount was measured using a blow-off charge amount measuring device (TB-500 manufactured by Toshiba Chemical Co., Ltd.), and the sign was reversed to calculate the charge amount per 1 g of toner. As a result, it was evaluated according to the following criteria.

⊚: Charge amount of 30 μC / g or more ◯: Charge amount of 24 to 29 μC / g Δ: Charge amount of 17 to 23 μC / g ×: Charge amount of less than 17 μC / g Moisture resistance is the same as that of positive charge property. The charge amount after standing for about 24 hours in an environment of temperature 35 ° C. and humidity 85% is calculated, and the difference is obtained from the amount of charge after standing for about 24 hours in the environment of temperature 20 ° C. and humidity 60%. It was evaluated according to the standard.

⊚: less than 2 μC / g ◯: less than 2 to 3 μC / g Δ: less than 3 to 4 μC / g x: more than 4 μC / g Measure the fixing temperature using a fixing tester that can change the applied temperature freely,
The results were evaluated according to the following criteria.

⊚: Less than 120 ° C. ∘: 120 to 139 ° C. Δ: 140 to 149 ° C. ×: 150 ° C. or more Non-offset property is offset by using a fixing tester capable of freely changing temperature and speed. The generated temperature was measured and the result was evaluated according to the following criteria.

⊚: 170 ° C. or higher ○: 155 to 169 ° C. Δ: 140 to 154 ° C. ×: less than 140 ° C. As for blocking resistance, about 10 g of toner is put in a 200 cc glass container and kept at about 40 ° C. After standing for about 120 hours in a glass container, the aggregation state of the toner when the taken out glass container was turned upside down was evaluated according to the following criteria.

⊚: Toner is uniformly dispersed. ◯: Toner is uniformly dispersed by tapping twice. Δ: Toner is uniformly dispersed by tapping 4 times. ×: Toner is not aggregated and dispersed. In the evaluation of moisture resistance, fixability, non-offset property and blocking resistance, ⊚ to Δ are practically usable.

Manufacturing Method of Dispersant A In a reaction vessel equipped with a stirrer, a thermometer, and a gas inlet tube, 900 parts by weight of deionized water, 25 parts by weight of methyl methacrylate,
75 parts by weight of 3-sodium sulfopropyl methacrylate was charged, and N ₂ gas was blown for about 30 minutes to expel the air in the reaction system. Next, the mixture was heated from the outside with stirring in a hot water bath to raise the temperature to 60 ° C., and 0.5 part by weight of ammonium persulfate was added. Stirring was continued at the same temperature for about 3 hours to obtain a polymer liquid (solid content: 3.3%) having a bluish white appearance and a viscosity of 340 centipoise (25 ° C.).

Examples 1 to 4 220 parts by weight of deionized water, 0.60 part by weight of sodium polyacrylate (solid content 3.3%), 2.42 part by weight of dispersant A, and 0.55 part by weight of sodium sulfate were mixed. Agitator,
Charge into a reaction vessel equipped with a distillation column and a thermometer, then mix and add the amounts of the monomers and additives shown in the composition of Table 1, keep the stirring speed at 300 rpm, and start the polymerization of the amount shown in Table 1. The agent was added. Then, the reaction vessel is heated from the outside in a hot water bath and the temperature in the reaction system is adjusted to 92
The temperature was raised to ° C and suspension polymerization was started. After the suspension polymerization was carried out for about 6 hours, the temperature in the reaction system was raised to about 100 ° C., and about 44 parts by weight of residual monomer and deionized water in the reaction system were allowed to flow out of the reaction system. The residual monomer of the polymer was reduced. After that, the temperature in the reaction system was set to about 90 ° C., 0.5 part by weight of sodium hydroxide was added, and alkali treatment was performed for about 30 minutes while keeping the temperature at 90 ° C. Then, the temperature in the reaction system was raised to room temperature. The resin was lowered, the resin was taken out from the reaction vessel, and the resin was washed with deionized water for about 5 minutes. Then, it was dried by a hot air dryer at 50 ° C. for about 48 hours to obtain a resin. The characteristic values of the obtained resin are shown in Table 2.

Next, 90 parts by weight of the obtained resin, 5 parts by weight of carbon black and 5 parts by weight of a low molecular weight polypropylene wax were mixed for about 20 minutes and then melt-kneaded for about 20 minutes with a mixer. The melt-kneading temperature was 10 ° C. higher than the softening temperature of the resin. Then, the kneaded product was indirectly cooled with water and coarsely pulverized, and then finely pulverized with a jet mill fine pulverizer and adjusted with a classifier to finally obtain a toner having an area average particle size of 10 to 11 μm. Table 2 shows the evaluation results of the positive charging property, moisture resistance, fixing property, non-offset property and blocking resistance of the obtained toner.

As shown in Table 2, the toners of Examples 1 and 2 showed positive chargeability and excellent charge level. Further, the toners of Examples 3 and 4 showed positive chargeability and the charge level was good. Furthermore, the toners of Examples 1 to 4 showed excellent humidity resistance with little attenuation of the charge amount. Regarding the fixability, the toners of Examples 1 to 3 were good, and the toner of Example 4 showed excellent fixability. Regarding the non-offset property, the toners of Examples 1 to 3 were excellent, and the toner of Example 4 showed good non-offset property. Regarding blocking resistance, the toner of Example 1 showed good blocking resistance, and the toners of Examples 2 and 3 showed excellent blocking resistance. The toner of Example 4 is
Although it was slightly inferior in blocking resistance, it was at a practical level.

Examples 5 to 6 Under the same conditions as in Examples 1 to 4 except that the monomers, additives and polymerization initiators shown in Table 1 were used except for the step of flowing out deionized water and residual monomers at 100 ° C. I got a resin. The characteristic values of the obtained resin are shown in Table 2. Further, the obtained resin was made into a toner under the same conditions as in Examples 1 to 4. The obtained toner has positive charging property, moisture resistance, fixing property,
Table 2 shows the evaluation results of the non-offset property and the blocking resistance.

As shown in Table 2, the positive charging property is as follows.
The toners of Examples 5 and 6 were positively charged, and the charge level was excellent. Further, the toners of Examples 5 and 6 were excellent in moisture resistance and fixability. Regarding the non-offset property and anti-blocking property, the toner of Example 5 showed good non-offset property and anti-blocking property, and the toner of Example 6 was slightly inferior in both non-offset property and anti-blocking property, but was practically usable. It was a level.

Examples 7 to 8 Except for using the monomers, additives and polymerization initiators shown in Table 1, except that the suspension polymerization temperature was set to 88 ° C. and deionized water and residual monomers were allowed to flow out at 100 ° C. Examples 1 to 4
Resin was obtained under the same conditions as. The characteristic values of the obtained resin are shown in Table 2. Further, the obtained resin was made into a toner under the same conditions as in Examples 1 to 4. Table 2 shows the evaluation results of the positive charging property, moisture resistance, fixing property, non-offset property and blocking resistance of the obtained toner. As shown in Table 2, with respect to the positive chargeability, the toners of Examples 7 and 8 have positive chargeability, the toner of Example 7 has a good charge level, and the toner of Example 8 has a slightly chargeable level. Although it was low, it was at a practical level. Also, Examples 7 and 8
All of the toners had excellent moisture resistance. Regarding the fixability, the toners of Examples 7 and 8 were slightly inferior, but were at a practical level. With respect to the anti-offset property and the anti-blocking property, the toners of Examples 7 and 8 exhibited excellent anti-offset property and anti-blocking property.

Example 9 A resin was obtained under the same conditions as in Examples 1 to 4 except that the suspension polymerization temperature was 140 ° C. and the monomers, additives and polymerization initiators shown in Table 1 were used. The characteristic values of the obtained resin are shown in Table 2. Furthermore, the obtained resin was used in Example 1
Toner was converted to toner under the same conditions as described above. Table 2 shows the evaluation results of the positive charging property, moisture resistance, fixing property, non-offset property and blocking resistance of the obtained toner. As shown in Table 2, with respect to the positive charging property, the toner of Example 9 exhibited the positive charging property, was excellent in the charging level, and was also excellent in the moisture resistance. In addition, it exhibited excellent fixability and good non-offset property. Although it was slightly inferior in blocking resistance, it was at a practical level.

Examples 10 to 15 Resins were obtained under the same conditions as in Examples 1 to 4 except that the monomers, additives and polymerization initiators shown in Table 1 were used. The characteristic values of the obtained resin are shown in Table 2. Further, the obtained resin was made into a toner under the same conditions as in Examples 1 to 4. Table 2 shows the evaluation results of the positive charging property, moisture resistance, fixing property, non-offset property and blocking resistance of the obtained toner.

As shown in Table 2, the positive charging property is as follows.
The toners of Examples 10 to 15 showed positive charging properties, and all had excellent charging levels. Further, the toners of Examples 10 to 14 showed excellent moisture resistance, and the toner of Example 15 was slightly inferior in moisture resistance, but it was at a practical level. Regarding the fixability, the toners of Examples 10 to 15 all showed good fixability. Regarding the non-offset property, the toners of Examples 10 to 15 were all excellent. With respect to blocking resistance, the toners of Examples 10, 11 and 13 were good, and the toners of Examples 12, 14 and 15 showed excellent blocking resistance.

[0037]

[Table 1]

[0038]

[Table 2]

Comparative Example 1 A resin was obtained in the same manner as in Examples 1 to 4 except that the monomers, additives and polymerization initiators shown in Table 3 were used.
The characteristic values of the obtained resin are shown in Table 4. Further, the obtained resin was made into a toner under the same conditions as in Examples 1 to 4.
Table 4 shows the evaluation results of the positive charging property, moisture resistance, fixing property, non-offset property and blocking resistance of the obtained toner. As shown in Table 4, the chargeability was inferior and the charge level was not satisfactory.

Comparative Example 2 A resin was obtained in the same manner as in Example 7 except that the monomers, additives and polymerization initiators shown in Table 3 were used. The characteristic values of the obtained resin are shown in Table 4. Further, the obtained resin was made into a toner under the same conditions as in Examples 1 to 4. Table 4 shows the evaluation results of the positive charging property, moisture resistance, fixing property, non-offset property and blocking resistance of the obtained toner.
As shown in Table 4, the fixability and blocking resistance were inferior and not practical.

Comparative Example 3 A resin was obtained in the same manner as in Examples 1 to 4 except that the monomers, additives and polymerization initiators shown in Table 3 were used.
The characteristic values of the obtained resin are shown in Table 4. Further, the obtained resin was made into a toner under the same conditions as in Examples 1 to 4.
Table 4 shows the evaluation results of the positive charging property, moisture resistance, fixing property, non-offset property and blocking resistance of the obtained toner. As shown in Table 4, the fixability was poor and it was not practical.

Comparative Example 4 A resin was obtained in the same manner as in Example 9 except that the polymerization temperature was 145 ° C. and the monomers, additives and polymerization initiators having the compositions shown in Table 3 were used. The characteristic values of the obtained resin are shown in Table 4. Further, the obtained resin was used in Examples 1 to 1.
Toner was formed under the same conditions as in No. 4. Table 4 shows the evaluation results of the positive charging property, moisture resistance, fixing property, non-offset property and blocking resistance of the obtained toner. As shown in Table 4,
It was impractical because of poor moisture resistance, non-offset property and blocking resistance.

Comparative Example 5 A resin was obtained in the same manner as in Examples 1 to 4 except that the monomers, additives and polymerization initiators having the compositions shown in Table 3 were used. The characteristic values of the obtained resin are shown in Table 4. Further, the obtained resin was made into a toner under the same conditions as in Examples 1 to 4. The obtained toner has positive charging property, moisture resistance, fixing property,
Table 4 shows the evaluation results of the non-offset property and blocking resistance. As shown in Table 4, the moisture resistance was poor and it was not practical.

[0044]

[Table 3]

[0045]

[Table 4]

The symbols in Tables 1 and 3 indicate the following components, respectively. St: Styrene PMS: p-methylstyrene nBA: n-Butyl acrylate MAA: Methacrylic acid MMA: Methyl methacrylate ET: 2-Ethoxyethyl methacrylate AET: 2-Ethoxyethyl acrylate MT: 2-Methoxyethyl methacrylate DBF : Dibutyl fumarate VAC: vinyl acetate DE: diethylaminoethyl methacrylate MSD: α-methylstyrene dimer BPO: benzoyl peroxide tBP: t-butylperoxybenzoate AIBN: azobisisobutyronitrile

[0047]

The toner using the binder resin of the present invention is excellent in fixability, non-offset property, blocking resistance, excellent positive chargeability, and has a stable charge amount. Further, the binder resin of the present invention does not use azobisisobutyronitrile, which has a problem of toxicity,
Further, by using the peroxide type polymerization initiator, a toner having a good positive charging property can be obtained and there is no environmental pollution.

Claims (3)

[Claims] 1. A glass transition containing an acrylic acid ester component and / or a methacrylic acid ester component having an ether group in an amount of 1 to 40% by weight in the total polymer component and a p-methylstyrene component in an amount of 1% by weight or more in the total polymer. The temperature is 40 to 68 ° C, the softening temperature is 80 to 140 ° C, and the acid value is 20.
mgKOH / g or less, weight average molecular weight of 3,000 to 8
50,000, number average molecular weight 1,000 to 45,000
A binder resin for a positively chargeable toner, characterized in that 2. A styrene component, an acrylic acid ester component, a methacrylic acid ester component, and at least one component selected from unsaturated dibasic acid components, the total amount of which is 60 to 60% based on the total polymer components. The binder resin for a positively chargeable toner according to claim 1, wherein the binder resin is 99% by weight. 3. At least one peroxide type polymerization initiator is used.
3. The binder resin for positively chargeable toner according to claim 1, wherein at least one kind is used.