JPH07120972A - Resin binder for toner and its production - Google Patents

Abstract

PURPOSE:To obtain a toner excellent in anti-offsetting property, electrostatic charge stability and blocking resistance as well as in fixability at a low temp. and adaptable even to a high-speed copying machine or printer. CONSTITUTION:This resin binder is a crosslinked styrene-acrylic copolymer obtd. by suspension-polymerizing polymerizable monomers including a styrenic monomer a (meth)acrylic monomer and a bi- or higher functional vinylic monomer at >=100 deg.C reaction temp. and has 110-150 deg.C softening temp., 50-70 deg.C glass transition temp., 2-45% fraction of gel and <=10mgKOH/g acid value. The mol.wt. of the max. peak in the mol.wt. distribution of the solvent-soluble component measured by gel permeation chromatography is <=15,000.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a binder resin for toner used for developing an electrostatic charge image or a magnetic latent image in an electrophotographic method, an electrostatic recording method, an electrostatic printing method and the like, and a method for producing the same. Yes, more specifically, fixability,
The present invention relates to a binder resin for a toner which can provide a toner excellent in non-offset property, charge stability and blocking resistance, and a method for producing the same.

[0002]

2. Description of the Related Art In copying machines, printers, facsimiles and the like used in electrophotography, electrostatic recording, electrostatic printing, etc., the speed of printing is increasing, and toner and carrier are generated when charge is generated in the developing process. Are vigorously stirred and mixed, and the fixing temperature has been lowered in the fixing step. Along with this, even in the toner and the binder resin for the toner used, not only the fixing performance at low temperature, but also the non-offset property that the toner does not migrate to the heating roller and other papers,
Performances such as charge stability for obtaining a stable image and blocking resistance that does not cause coagulation during storage of toner have been demanded.

In order to satisfy the fixing performance at a low temperature in response to such a demand, a solution polymerization method has been taken to reduce the molecular weight of the styrene-acrylic copolymer. For example, in a non-crosslinked bander resin composed of a high molecular weight polymer and a low molecular weight polymer, a method of reducing the molecular weight of the low molecular weight polymer has been performed. However, in such a method, although the fixing property at low temperature is improved, the strength of the binder resin is reduced,
There is a problem in that the toner is crushed when the charge is generated and the charge amount changes, resulting in poor image stability.

[0004]

In order to improve the strength of the binder resin, a low molecular weight polymer of a crosslinked binder resin composed of a crosslinked polymer and a low molecular weight polymer is polymerized by a solution polymerization method to lower the molecular weight. However, there are problems such as odor and image stability due to the influence of the residual solvent and deterioration of non-offset property due to the influence of the low molecular weight polymer. Further, for the purpose of improving the image stability of the cross-linking binder resin, a method of introducing an unsaturated dibasic acid has also been carried out, but it is not possible to improve the image stability unless a large amount is introduced, On the contrary, it has a problem that the moisture resistance is lowered.

In addition, since such a cross-linking binder resin polymerizes a low-molecular weight polymer by a solution polymerization method and a cross-linking polymer by a suspension polymerization method,
It was also inferior in productivity. An object of the present invention is to provide a binder resin for a toner which is excellent in fixing performance at low temperature, and which is capable of obtaining a toner excellent in non-offset property, charging stability and blocking resistance, and a toner having excellent productivity. To provide a method for producing a binder resin for use.

[0006]

That is, the binder resin for a toner of the present invention contains a polymerizable monomer component containing a styrene-based monomer, a (meth) acrylic-based monomer and a bifunctional or higher functional vinyl-based monomer at 100 ° C. or higher. A crosslinked styrene-acrylic copolymer obtained by suspension polymerization at a reaction temperature, having a softening temperature of 110 to 150 ° C, a glass transition temperature of 50 to 70 ° C, a gel fraction of 2 to 45% by weight, and a solvent. The maximum peak molecular weight in the molecular weight distribution of the solute by gel permeation chromatography is 1
It is characterized by having an acid value of 5,000 or less and an acid value of 10 mgKOH / g or less.

The method for producing a binder resin for a toner according to the present invention uses a polymerizable monomer component containing a styrene-based monomer, a (meth) acrylic-based monomer, and a bifunctional or higher functional vinyl-based monomer with a 10-hour half-life temperature. 60
By carrying out suspension polymerization at a reaction temperature of 100 ° C. or higher in the presence of a peroxide polymerization initiator of ˜90 ° C. and a peroxide polymerization initiator of 10-hour half-life temperature of 95 to 110 ° C., The softening temperature is 110 to 150 ° C., the glass transition temperature is 50 to 70 ° C., the gel fraction is 2 to 45% by weight, and the solvent-soluble component has a maximum peak molecular weight of 15,000 or less in the molecular weight distribution by gel permeation chromatography.
It is characterized in that a crosslinked styrene-acrylic copolymer having an acid value of 10 mgKOH / g or less is obtained.

The polymerizable monomer component used in the binder resin for toner of the present invention is a styrene-based monomer,
It contains a (meth) acrylic monomer and a bifunctional or higher functional vinyl monomer, and the amount used is such that the glass transition temperature of the obtained styrene-acrylic copolymer is 5
The temperature can be appropriately set to be in the range of 0 to 70 ° C., but it is preferable to use the styrene-based monomer in the range of 50% by weight or more in all the monomer components from the viewpoint of the moisture resistance of the toner. Examples of the styrene-based monomer used in the present invention include styrene, o-methylstyrene, m
-Methylstyrene, p-methylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, 3,4-dichlorostyrene, p-ethylstyrene,
2,4 dimethyl styrene, pn-butyl styrene, p
-Tert butyl styrene, pn-hexyl styrene, pn-octyl styrene, pn-nonyl styrene, pn-decyl styrene, pn-dodecyl styrene, α-methyl styrene and the like, and these are used alone. Alternatively, two or more kinds can be used in combination. Among them, styrene, p-methylstyrene and α-methylstyrene are preferable, and styrene is particularly preferable. By using such a styrene-based monomer, the moisture resistance of the toner can be improved.

The (meth) acrylic monomers (acrylic monomers or methacrylic monomers) include acrylic acid and methacrylic acid; ethyl acrylate, methyl acrylate, n-butyl acrylate, isobutyl acrylate, propyl acrylate. Acrylic acid esters such as 2-ethylhexyl acrylate, stearyl acrylate, lauryl acrylate, 2-ethoxyethyl acrylate, 2-methoxyethyl acrylate, 2-budoxyethyl acrylate; ethyl methacrylate, methyl methacrylate, methacrylic acid n-butyl, isobutyl methacrylate, propyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, lauryl methacrylate, glycidyl methacrylate, cyclohexyl methacrylate, methacrylic acid Methacrylic acid esters such as ethylaminoethyl, dimethylaminoethyl methacrylate, 2-ethoxyethyl methacrylate, 2-methoxyethyl methacrylate, 2-budoxyethyl methacrylate and the like can be mentioned, and these can be used alone or in combination of two or more kinds. be able to. Among them, methacrylic acid, methyl methacrylate and n-butyl methacrylate are preferable.

Further, a bifunctional or higher functional vinyl-based monomer which is a cross-linking monomer, that is, a reactive vinyl-based monomer having two or more reactive double bonds in one molecule is, for example, divinylbenzene or divinylnaphthalene. Aromatic divinyl compound, ethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, polyethylene glycol di (meth) acrylate,
Dipropylene glycol di (meth) acrylate, 1,
Examples thereof include 3-butylene glycol di (meth) acrylate and bisphenol A derivative-based di (meth) acrylate, and these can be used alone or in combination of two or more kinds. Among them, divinylbenzene, 1,3
-Butylene glycol dimethacrylate is preferred. These bifunctional or higher functional vinyl monomers are preferably used in the range of 0.3 to 5% by weight, more preferably 0.4 to 4.5% by weight, based on the total monomer components. This is because if it is less than 0.3% by weight, the cross-linking structure of the binder resin is insufficient and the non-offset property of the toner tends to be poor. This is because there is a tendency to be damaged.

The binder resin for a toner of the present invention is obtained by suspension polymerization of a polymerizable monomer component containing the above-mentioned styrene monomer and (meth) acrylic monomer as main components at a reaction temperature of 100 ° C. or higher. Is important. The binder resin composed of a styrene-acrylic copolymer is generally obtained by a polymerization method such as a suspension polymerization method, a solution polymerization method, an emulsion polymerization method or a bulk polymerization method.
However, in the solution polymerization method, it is difficult to remove the solvent used, and the residual solvent causes problems such as odor and image stability. In addition, the emulsion polymerization method has a problem that the emulsifier used remains in the binder resin and thus has poor moisture resistance. Further, the bulk polymerization method is difficult to control heat generation and is extremely inferior in productivity. On the other hand, the suspension polymerization method does not have the problem of odor due to the residual solvent because it does not use a solvent, and it is easy to control the heat generation, and the amount of the dispersant used is small and the moisture resistance is not impaired. Therefore, as the binder resin for low odor toner, the one polymerized by the suspension polymerization method is most suitable. In addition, by carrying out suspension polymerization at a reaction temperature of 100 ° C. or higher, the molecular weight of the binder resin can be reduced and the fixing property of the toner can be improved, and
The polymerization initiator is efficiently consumed and the productivity can be improved, and it is preferably in the range of 110 to 145 ° C.

In the binder resin for toner of the present invention, the softening temperature is 110 to 150 ° C., the glass transition temperature is 50 to 70 ° C., the gel fraction is 2 to 45% by weight, and the solvent permeation gel permeation chromatography. The maximum peak molecular weight in the molecular weight distribution by 15,000 or less,
It is important that the acid value is 10 mgKOH / g or less in order to improve properties such as toner fixability, non-offset property, blocking resistance, and charge stability.

This is because when the softening temperature is less than 110 ° C., the toner non-offset property is poor, and when it exceeds 150 ° C., the toner fixing property is poor, and more preferably 11
It is in the range of 5 to 145 ° C. Also, the glass transition temperature is 5
If the temperature is lower than 0 ° C, the toner has poor blocking resistance, and
This is because if the temperature exceeds 0 ° C., the fixing property of the toner is deteriorated, and the range is preferably 52 to 68 ° C. 2% gel fraction
If it is less than 45% by weight, the non-offset property of the toner is inferior, and if it exceeds 45% by weight, the fixing property of the toner is inferior. This is because when the maximum peak molecular weight in the molecular weight distribution by gel permeation chromatography of the solvent-soluble component exceeds 15,000, the fixability of the toner is poor, and the range is preferably 13,000 or less. Further, when the acid value exceeds 10 mgKOH / g, the moisture resistance of the toner is impaired and the charging stability is deteriorated, and the range is preferably 8 mgKOH / g or less.

The binder resin for a toner of the present invention comprises a polymerizable monomer component containing the above-mentioned styrene-based monomer, (meth) acrylic-based monomer and bifunctional or higher functional vinyl-based monomer at a reaction temperature of 100 ° C. or higher at 2 to 4 kg / g. cm
It is produced by carrying out suspension polymerization under a pressure of about ² . In the present invention, the polymerization initiator used for suspension polymerization has a peroxide polymerization initiator having a 10-hour half-life temperature of 60 to 90 ° C., preferably 60 to 80 ° C. and a 10-hour half-life temperature of 95-110 ° C, preferably 96-107
Used in combination with a peroxide type polymerization initiator at ℃. This is 10
This is because the use of a peroxide-based polymerization initiator having a time half-life temperature of 60 to 90 ° C. can reduce the molecular weight of the solvent-soluble component of the binder resin. Also, by using a peroxide-based polymerization initiator having a 10-hour half-life temperature of 95 to 110 ° C., the glass transition temperature of the binder resin can be raised and the blocking resistance can be improved.

As the peroxide type polymerization initiator having a 10-hour half-life temperature of 60 to 90 ° C., for example, lauryl peroxide (10-hour half-life temperature = 62 ° C.), coumerperoxy octoate (68 ° C.) , Benzoyl peroxide (74 ° C), t-butylperoxy (2-ethylhexanoate) (72.5 ° C), m-toluoyl peroxide (73 ° C), t-butylperoxyisobutyrate (78). C.), 1,1-bis (t-butylperoxy)
3,3,5-trimethylcyclohexane (90 ° C.) and the like can be mentioned, and these can be used alone or in combination of two or more kinds. Among them, benzoyl peroxide is preferable. These polymerization initiators are preferably used in the range of 3 to 9% by weight, more preferably 3.5 to 8.5% by weight, based on the total amount of the styrene-based monomer and the (meth) acrylic-based monomer. Is.

The 10-hour half-life temperature is 95 to 110.
As the peroxide-based polymerization initiator at 0 ° C., for example, t-butylperoxylaurate (10-hour half-life temperature = 96
℃), cyclohexanone peroxide (97 ℃), t
-Butyl peroxyisopropyl carbonate (98
℃), t-butyl peroxyacetate (102 ℃),
t-bityl peroxybenzoate (104 ° C), di-
Examples thereof include t-butyl peroxyisophthalate (107 ° C.), and these can be used alone or in combination of two or more kinds. Of these, t-butyl peroxybenzoate is preferable. These polymerization initiators are preferably used in the range of 0.2 to 2% by weight, more preferably 0.2 to 1.5% by weight, based on the total amount of the styrene-based monomer and the (meth) acrylic-based monomer. Is the range.

As the dispersant used in the present invention, polyvinyl alcohol usually used in suspension polymerization,
Examples thereof include sodium polyacrylate, polyether dispersants, ethylene oxide dispersants and the like. Further, as a dispersion aid, sodium sulfate, sodium carbonate, calcium carbonate, manganese sulfate, hydrogen peroxide solution, boric acid or the like can be used in combination. The amount of deionized water used in the suspension polymerization is 1.5 to a weight ratio with respect to the polymerizable monomer component in order to alleviate the heat generation during the polymerization and make the reaction stable.
The range of 2.5 is preferable, and the range of 1.8 to 2.3 is more preferable.

In the present invention, the suspension polymerization is carried out at a reaction temperature of 100 ° C. or higher, but the temperature rising time from room temperature to the reaction temperature is preferably about 20 to 90 minutes. This is because if it is less than 20 minutes, it tends to be difficult to obtain a crosslinked structure of the binder resin, and if it exceeds 90 minutes, the effect of lowering the molecular weight of the binder resin tends to be reduced.

Further, in the present invention, for the purpose of reducing benzoic acid, which is a decomposition by-product of the polymerization initiator, and improving the charge stability of the toner, the suspension polymerization is carried out at 85 ° C.
It is also possible to perform alkali treatment at the above temperature. If the alkali treatment temperature is lower than 85 ° C, the effect of reducing benzoic acid and the like is not sufficient, and the temperature is preferably 88 ° C or higher. Examples of the alkali used include hydroxides of alkali metals such as lithium, sodium, potassium and rubidium, and sodium hydroxide is preferable. The amount of these alkalis used is styrene monomer and (meth)
It is preferably in the range of 0.1 to 2% by weight, more preferably 0.3 to
It is in the range of 1.5% by weight.

Further, in the present invention, after the suspension polymerization is carried out, the residual monomer can be further reduced by carrying out distillation for outflowing deionized water and the residual monomer from the reaction system. . When the distillation step and the alkali treatment are used in combination, it is preferable to carry out the distillation before or at the same time as the alkali treatment. The distillation is preferably carried out at a temperature of 100 ° C. or higher, which is the boiling point of deionized water, and it is preferable to let out an amount of 5 to 30% by weight of the amount of deionized water used for suspension polymerization, more preferably 10 to It is in the range of 25% by weight.

In the present invention, the glass transition temperature was determined by the DSC method (heating rate 10 ° C./min) after the sample was heated to 100 ° C. and melt-quenched. As for the softening temperature, a flow tester (CFT-500 manufactured by Shimadzu Corp.) having a nozzle of 1 mmφ × 10 mm was used, and when half of the sample amount flowed out under the conditions of a load of 30 Kgf and a heating rate of 3 ° C./min. Indicated by the temperature.
The acid value was determined using a titration method with KOH.

The molecular weight was determined by gel permeation chromatography (HCL-8020 manufactured by Toso Co., Ltd.) in terms of polystyrene. Specifically, regarding the measuring method in the molecular weight measurement, the calculation of the molecular weight and the molecular weight distribution were obtained from the relationship between the calibration curve prepared by several kinds of monodisperse polyethylene standard samples and the counted values. At this time, the polyethylene standard sample has a molecular weight of 6 × 10.
² , 2.1 × 10 ³ , 4 × 10 ³ , 1.75 × 10 ⁴ ,
5.1 × 10 ⁴ , 1.1 × 10 ⁵ , 3.9 × 10 ⁵ ,
Examples include those of 8.6 × 10 ⁵ , 2 × 10 ⁶ , and 4.48 × 10 ⁶ , and it is preferable to select and use 10 or more. In addition, columns TSKgel, G1000H, G20
00H, G2500H, G3000H, G4000H,
G5000H, G6000H, G7000H, GMH and the like can be mentioned, and it is preferable to use them in combination.

The gel fraction was measured by placing 0.5 g of the sample in 50 ml of tetrahydrofuran (THF), heating and dissolving at 60 ° C. for 3 hours, filtering through a glass filter covered with Celite # 545, and using a vacuum dryer at 80 ° C. The weight when fully dried was divided by the initial weight.

[0024]

EXAMPLES The present invention will be specifically described below with reference to examples. In the embodiment, the fixing property is such that the fixing speed is set to 350 by using a copying machine capable of freely changing the fixing temperature.
mm5 / min, initial density (ID) 0.95-1.0
5, the temperature at which the ratio of the density after rubbing with a sand eraser and the initial density exceeds 85% was determined as the fixing temperature, and evaluated according to the following criteria. ⊚: less than 150 ° C. ∘: 151 to 170 ° C. x: exceeds 170 ° C.

The non-offset property is obtained by using a copying machine whose temperature can be freely changed and fixing speed of 350 mm /
Minutes were evaluated according to the following criteria according to the temperature at which double transfer onto paper was developed. ⊚: 210 ° C. or more ◯: 200 to less than 210 ° C. ×: less than 200 ° C. For blocking resistance, about 5 g of toner was weighed in a sample bottle, placed in a hot air dryer kept at about 50 ° C., left for 72 hours, and then taken out. The aggregation state of the toner when the sample bottle was turned upside down was evaluated according to the following criteria. ⊚: Toner that is tapped once is uniformly dispersed. ◯: Toner is uniformly dispersed when tapped three times.

Examples 1-11 220 parts by weight of deionized water, 0.2 polyvinyl alcohol
One part by weight and 0.03 part by weight of hydrogen peroxide solution were mixed and charged into a reaction vessel equipped with a distillation column and a stirrer. Next, each component of the polymerizable monomer as shown in Table 1 was added,
It mixed and put into the reaction container. Furthermore, the stirring speed is set to 25
After the polymerization initiator shown in Table 1 was charged at 0 rpm, the reaction vessel was closed. Then, the temperature rise in the reaction system is started, and the temperature in the reaction system is reduced to 130 in about 45 minutes after the temperature rise is started.
Suspension polymerization was initiated at 0 ° C. and a pressure of 3.5 Kg / cm ² . About 150 minutes after the suspension polymerization was started, the temperature in the reaction system was lowered to 90 ° C., and the pressure in the reaction vessel was adjusted to normal pressure.
The stirring rotation speed was 300 rpm. Then, the temperature in the reaction system was raised to 100 ° C. and the distillation step was performed. The mixed solution of deionized water and the remaining monomer was allowed to flow out from the reaction system for about 2 hours, and when the amount of the outflow reached 44 parts by weight, the temperature in the reaction system was maintained at about 90 ° C. 0.5 part by weight of sodium was added and alkali treatment was performed for about 30 minutes.
Then, the temperature in the reaction system was cooled to room temperature, the resulting resin was taken out, thoroughly washed with deionized water, then the deionized water was thoroughly dehydrated and dried at 50 ° C. for about 24 hours. Then, a binder resin was obtained. The obtained resin had a glass transition temperature (Tg), a softening temperature, an acid value, a gel fraction, a molecular weight distribution and a residual monomer amount as shown in Table 2.

Further, 91 parts by weight of the obtained binder resin, 5 parts by weight of carbon black, 1 part by weight of the charge control agent and 3 parts by weight of polypropylene wax were mixed and the resin temperature during kneading was softened by using an internal mixer. The mixture was kneaded for 30 minutes at a temperature 20 ° C higher than the temperature. Then, fine pulverization and classification are performed to obtain a particle size of 5 to 20 μm.
Toner was obtained. The toner thus obtained was used to evaluate the fixability, non-offset property and blocking resistance, and the results are shown in Table 2.

Example 12 220 parts by weight of deionized water, polyvinyl alcohol 0.2
One part by weight and 0.03 part by weight of hydrogen peroxide solution were mixed and charged into a reaction vessel equipped with a distillation column and a stirrer. Next, each component of the polymerizable monomer as shown in Table 1 was added,
It mixed and put into the reaction container. Furthermore, the stirring speed is set to 25
After the polymerization initiator shown in Table 1 was charged at 0 rpm, the reaction vessel was closed. Next, the temperature rise in the reaction system is started, and the temperature in the reaction system is increased to 110 in about 45 minutes after the start of the temperature rise.
Suspension polymerization was started at 0 ° C. About 150 minutes after the suspension polymerization was started, the temperature in the reaction system was lowered to 90 ° C., the pressure in the reaction vessel was set to normal pressure, and the stirring rotation speed was 300 rpm.
And Then, 0.5 part by weight of sodium hydroxide was added and alkali treatment was performed for about 30 minutes. Then, the temperature in the reaction system was cooled to room temperature, the resulting resin was taken out, thoroughly washed with deionized water, then the deionized water was thoroughly dehydrated and dried at 50 ° C. for about 24 hours. Then, a binder resin was obtained. The obtained resin had a glass transition temperature (Tg), a softening temperature, an acid value, a gel fraction, a molecular weight distribution and a residual monomer amount as shown in Table 2. Further, a toner was obtained by using the obtained binder resin in the same manner as in Example 1. The toner thus obtained was used to evaluate the fixability, non-offset property and blocking resistance, and the results are shown in Table 2.

Example 13 220 parts by weight of deionized water, polyvinyl alcohol 0.2
One part by weight and 0.03 part by weight of hydrogen peroxide solution were mixed and charged into a reaction vessel equipped with a distillation column and a stirrer. Next, each component of the polymerizable monomer as shown in Table 1 was added,
It mixed and put into the reaction container. Furthermore, the stirring speed is set to 25
After the polymerization initiator shown in Table 1 was charged at 0 rpm, the reaction vessel was closed. Then, the temperature rise in the reaction system is started, and the temperature in the reaction system is increased to 145 in about 45 minutes after the temperature rise is started.
Suspension polymerization was started at 0 ° C. About 150 minutes after the suspension polymerization was started, the temperature in the reaction system was lowered to 90 ° C., the pressure in the reaction vessel was set to normal pressure, and the stirring rotation speed was 300 rpm.
And Then, 0.5 part by weight of sodium hydroxide was added and alkali treatment was performed for about 30 minutes. Then, the temperature in the reaction system was cooled to room temperature, the resulting resin was taken out, thoroughly washed with deionized water, then the deionized water was thoroughly dehydrated and dried at 50 ° C. for about 24 hours. Then, a binder resin was obtained. The obtained resin had a glass transition temperature (Tg), a softening temperature, an acid value, a gel fraction, a molecular weight distribution and a residual monomer amount as shown in Table 2. Further, a toner was obtained by using the obtained binder resin in the same manner as in Example 1. The toner thus obtained was used to evaluate the fixability, non-offset property and blocking resistance, and the results are shown in Table 2.

Comparative Examples 1 to 4 220 parts by weight of deionized water, 0.2 polyvinyl alcohol
One part by weight and 0.03 part by weight of hydrogen peroxide solution were mixed and charged into a reaction vessel equipped with a distillation column and a stirrer. Next, each component of the polymerizable monomer as shown in Table 1 was added,
It mixed and put into the reaction container. Furthermore, the stirring speed is set to 25
After the polymerization initiator shown in Table 3 was charged at 0 rpm, the reaction vessel was closed. Then, the temperature rise in the reaction system is started, and the temperature in the reaction system is reduced to 130 in about 45 minutes after the temperature rise is started.
Suspension polymerization was initiated at 0 ° C. and a pressure of 3.5 Kg / cm ² . About 150 minutes after the suspension polymerization was started, the temperature in the reaction system was lowered to 90 ° C., and the pressure in the reaction vessel was adjusted to normal pressure.
The stirring rotation speed was 300 rpm. Then, the temperature in the reaction system was raised to 100 ° C. and the distillation step was performed. A mixed solution of deionized water and the remaining monomer was allowed to flow out from the reaction system for about 2 hours, and when the amount of outflow reached 44 parts by weight, the temperature in the reaction system was maintained at about 90 ° C. 0.5 part by weight of sodium was added and alkali treatment was performed for about 30 minutes.
Then, the temperature in the reaction system was cooled to room temperature, the resulting resin was taken out, thoroughly washed with deionized water, then the deionized water was thoroughly dehydrated and dried at 50 ° C. for about 24 hours. Then, a binder resin was obtained. The obtained resin had the glass transition temperature (Tg), softening temperature, acid value, gel fraction, molecular weight distribution and residual monomer amount as shown in Table 4. Further, a toner was obtained by using the obtained binder resin in the same manner as in Example 1. The obtained toner was used to evaluate the fixability, non-offset property and blocking resistance, and the results are shown in Table 4.

Comparative Example 5 220 parts by weight of deionized water, 0.2 of polyvinyl alcohol
One part by weight and 0.03 part by weight of hydrogen peroxide solution were mixed and charged into a reaction vessel equipped with a distillation column and a stirrer. Next, each component of the polymerizable monomer as shown in Table 1 was added,
It mixed and put into the reaction container. Furthermore, the stirring speed is set to 25
After the polymerization initiator shown in Table 3 was charged at 0 rpm, the reaction vessel was closed. Then, the temperature rise in the reaction system is started, and the temperature in the reaction system is reduced to 130 in about 45 minutes after the temperature rise is started.
Suspension polymerization was initiated at 0 ° C. and a pressure of 3.5 Kg / cm ² . About 150 minutes after the suspension polymerization was started, the temperature in the reaction system was lowered to 90 ° C., and the pressure in the reaction vessel was adjusted to normal pressure.
The stirring rotation speed was 300 rpm. Then, 0.5 part by weight of sodium hydroxide was added and alkali treatment was performed for about 30 minutes. Then, the temperature in the reaction system was cooled to room temperature, the resulting resin was taken out, thoroughly washed with deionized water, then the deionized water was thoroughly dehydrated and dried at 50 ° C. for about 24 hours. Then, a binder resin was obtained. The obtained resin has a glass transition temperature (Tg) as shown in Table 4,
The softening temperature, acid value, gel fraction, molecular weight distribution and residual monomer amount. Further, a toner was obtained by using the obtained binder resin in the same manner as in Example 1. The obtained toner was used to evaluate the fixability, non-offset property and blocking resistance, and the results are shown in Table 4.

Comparative Examples 6 to 7 220 parts by weight of deionized water, 0.2 polyvinyl alcohol
One part by weight and 0.03 part by weight of hydrogen peroxide solution were mixed and charged into a reaction vessel equipped with a distillation column and a stirrer. Next, each component of the polymerizable monomer as shown in Table 1 was added,
It mixed and put into the reaction container. Furthermore, the stirring speed is set to 25
After the polymerization initiator shown in Table 3 was charged at 0 rpm, the reaction vessel was closed. Then, the temperature rise in the reaction system is started, and the temperature in the reaction system is reduced to 130 in about 45 minutes after the temperature rise is started.
Suspension polymerization was initiated at 0 ° C. and a pressure of 3.5 Kg / cm ² . About 300 minutes after the suspension polymerization was started, the temperature in the reaction system was lowered to 90 ° C., and the pressure in the reaction vessel was adjusted to normal pressure.
The stirring rotation speed was 300 rpm. Then, the temperature in the reaction system was raised to 100 ° C. and the distillation step was performed. A mixed solution of deionized water and the remaining monomer was allowed to flow out from the reaction system for about 2 hours, and when the amount of outflow reached 44 parts by weight, the temperature in the reaction system was maintained at about 90 ° C. 0.5 part by weight of sodium was added and alkali treatment was performed for about 30 minutes.
Then, the temperature in the reaction system was cooled to room temperature, the resulting resin was taken out, thoroughly washed with deionized water, then the deionized water was thoroughly dehydrated and dried at 50 ° C. for about 24 hours. Then, a binder resin was obtained. The obtained resin had the glass transition temperature (Tg), softening temperature, acid value, gel fraction, molecular weight distribution and residual monomer amount as shown in Table 4. Further, a toner was obtained by using the obtained binder resin in the same manner as in Example 1. The obtained toner was used to evaluate the fixability, non-offset property and blocking resistance, and the results are shown in Table 4.

[0033]

[Table 1]

[0034]

[Table 2]

[0035]

[Table 3]

[0036]

[Table 4]

The symbols of monomers and polymerization initiators shown in Tables 1 and 3 represent the following compounds, respectively. St; styrene nBA; n-butyl acrylate MAA; methacrylic acid BDMA; 1,3-butylene glycol dimethacrylate BPO; benzoyl peroxide PZ; t-butyl peroxybenzoate.

As is apparent from Table 2, the toners of Examples 1, 2, 5, 8 and 9 using the binder resin of the present invention have any of fixing property, non-osset property and blocking resistance. Was also excellent. Examples 3, 7, 1
The toners of 0, 11 and 13 were excellent in fixability and non-offset property, and also had good blocking resistance. The toners of Examples 4 and 12 were excellent in non-offset property, anti-blocking property, and good fixing property. Example 6
The toner of No. 2 was excellent in fixability and blocking resistance, and was also good in non-offset property. Also, with any toner, a stable image is obtained even after printing a plurality of sheets,
It had excellent charge stability.

On the other hand, Comparative Examples 1, 5 and 7 were excellent in non-offset property and blocking resistance, but poor in fixability. The toner of Comparative Example 2 was excellent in fixability, but was inferior in non-offset property and blocking resistance. The toner of Comparative Example 3 had excellent fixability and good non-offset property, but was inferior in blocking resistance. The toner of Comparative Example 4 was excellent in fixing property and non-offset property, and was also excellent in blocking resistance, but the image after printing a plurality of sheets was uneven and the charging stability was poor. The toner of Comparative Example 6 was excellent in fixing property and non-offset property, but was inferior in blocking resistance.

[0040]

The binder resin for toner of the present invention is
It is possible to obtain a toner obtained by suspension polymerization at a high reaction temperature, which has excellent fixing performance at low temperatures and also has excellent non-offset properties, charge stability and blocking resistance.

Claims (4)

[Claims] 1. A crosslinked styrene-acrylic copolymer obtained by suspension polymerization of a polymerizable monomer component containing a styrene monomer, a (meth) acrylic monomer and a bifunctional or higher functional vinyl monomer at a reaction temperature of 100 ° C. or higher. It is a polymer having a softening temperature of 110 to 150 ° C., a glass transition temperature of 50 to 70 ° C., a gel fraction of 2 to 45% by weight, and a solvent-soluble component having a maximum peak in a molecular weight distribution by gel permeation chromatography. Molecular weight of 15,000 or less,
A binder resin for a toner having an acid value of 10 mgKOH / g or less. 2. A polymerizable monomer component containing a styrene-based monomer, a (meth) acrylic-based monomer, and a bifunctional or higher functional vinyl-based monomer, and a 10-hour half-life temperature of 60.
By carrying out suspension polymerization at a reaction temperature of 100 ° C. or higher in the presence of a peroxide polymerization initiator of ˜90 ° C. and a peroxide polymerization initiator of 10-hour half-life temperature of 95 to 110 ° C., The softening temperature is 110 to 150 ° C., the glass transition temperature is 50 to 70 ° C., the gel fraction is 2 to 45% by weight, and the solvent-soluble component has a maximum peak molecular weight of 15,000 or less in the molecular weight distribution by gel permeation chromatography.
A method for producing a binder resin for a toner, which comprises obtaining a crosslinked styrene-acrylic copolymer having an acid value of 10 mgKOH / g or less. 3. After the suspension polymerization, 5 to 35% by weight of deionized water and the residual monomer with respect to the deionized water used for the suspension polymerization are flowed out of the reaction system. The method for producing the binder resin for toner according to claim 2. 4. The method for producing a binder resin for a toner according to claim 2, wherein the suspension treatment is followed by an alkali treatment at a temperature of 85 ° C. or higher.