JPH07179505A - Production of toner-bonding resin - Google Patents

Abstract

PURPOSE:To obtain a binder resin for toners excellent in environmental dependency, particularly in humidity resistance by mixing a polymer of high molecular weight and a polymer of low molecular weight homogeneously. CONSTITUTION:After polymerization of the high-molecular weight polymer according to the emulsion polymerization process, the low-molecular weight polymer component is prepared by the suspension polymerization in the presence of the emulsion containing high MW polymer blending a nonionic dispersant or dividing the dispersant into 2 portions and adding each before and after the charge of the monomers for the low-molecular weight polymer. The dispersant has less than 55dyne/cm of surface tension of its 0.2% aqueous solution at 20 deg.C. An excellent binder resin for toners is obtained by this manufacturing process.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a resin for a toner used in an electrophotographic method, an electrostatic printing method, and the like, and more specifically, a toner excellent in environmental dependency as a toner, particularly excellent in moisture resistance. The present invention relates to a method for producing a binder resin for automobiles.

[0002]

2. Description of the Related Art A typical image forming process using electrophotography or electrostatic printing is to uniformly charge a photoconductive insulating layer, expose the insulating layer, and then charge the exposed portion. To form an electrical latent image by dissipating the latent image, and visualized by attaching a fine powder toner having an electric charge to the latent image, the obtained visible image on a transfer material such as transfer paper. It comprises a transfer step of transferring and a fixing step of permanently fixing by heating or pressing.

As the toner and the binder resin for the toner used in such an electrophotographic method or electrostatic printing method, various performances are required in each of the above steps. For example, in the developing process, the toner and the binder resin for the toner retain the charge amount suitable for the copying machine without being affected by the surrounding environment such as temperature and humidity in order to attach the toner to the electric latent image. I have to do it. Also,
In the fixing process using the heat roller fixing method, the non-offset property that does not adhere to the heat roller and the fixability on paper must be good. Further, blocking resistance that toner does not block during storage in a copying machine is also required.

Conventionally, as a resin for toner, styrene-
Acrylic resins are often used, and linear type resins and crosslinked type resins are used. As a linear type resin, a resin in which a high-molecular weight polymer and a low-molecular weight polymer are mixed to improve fixing property, non-offset property and the like is known. Further, in the case of cross-linking type resins, the molecular weight distribution is broadened by cross-linking to improve the fixability and non-offset property. In particular, research on linear type resins is progressing,
JP-B-63-32182 and JP-A-62-9356.
As described in Japanese Unexamined Patent Publication (Kokai), etc., attempts have been made to improve the fixability and non-offset property by controlling the high molecular weight region and low molecular weight region of the resin and the molecular weight.

[0005]

However, in the toner using such a resin, although the balance between the fixability and the non-offset property is improved, the environmental dependence of the charging property that affects the image density, In particular, there is a problem in the change of the charge amount (humidity resistance) due to the change of humidity. In particular,
The number of printed sheets is increasing with the increase in size and speed of copiers and printers, and even when printing a large number of sheets, there is little change in charging characteristics over time, and there is little change in image density. Toners are becoming more demanding. Therefore, an object of the present invention is to obtain a toner binder resin which can provide a toner having a small change in image density even when printing a large number of sheets and having excellent environmental dependence.

[0006]

In view of such circumstances, the inventors of the present invention have made earnest studies on a method for producing a binder resin for toner, and as a result, by using a specific dispersant or by adding a dispersant. It was found that a binder resin for toner excellent in toner environmental dependence can be obtained by carrying out the above-mentioned method by a specific method, and arrived at the present invention. That is, the method for producing a binder resin for a toner of the present invention comprises the steps of polymerizing a high molecular weight polymer component by an emulsion polymerization method, and then adding a 0.2% aqueous solution at 20 ° C. in the presence of an emulsion of the high molecular weight polymer component. The low molecular weight polymer component is polymerized by suspension polymerization using a nonionic dispersant having a surface tension of 55 dyne / cm or less. In addition, after polymerizing the high molecular weight polymer component by an emulsion polymerization method, in the presence of the emulsion of the high molecular weight polymer component, when suspension polymerizing the low molecular weight polymer component, a monomer for the low molecular weight polymer is used. It is characterized in that the nonionic dispersant is dividedly added before and after the addition of.

The binder resin for toner obtained by the present invention is a mixture of a high molecular weight polymer component and a low molecular weight polymer component uniformly, and both polymers are styrenic monomers and other copolymerizable vinyl. It is composed of a polymer or a copolymer composed of a system monomer and the like, and particularly styrene-
Those made of an acrylic copolymer are preferable. In the present invention, as the styrenic monomer used for the polymerization of the high molecular weight polymer component and the low molecular weight polymer component,
Styrene, o-methylstyrene, m-methylstyrene,
p-methylstyrene, α-methylstyrene, p-ethylstyrene, 2,4-dimethylstyrene, pn-butylstyrene, p-tert-butylstyrene, pn-hexylstyrene, pn-octylstyrene, pn-
Nonyl styrene, pn-densyl styrene, pn-
Dodecyl styrene, p-phenyl styrene, 3,4-dichloro styrene, etc. are mentioned, Especially, styrene is preferable. These styrenic monomers may be used alone or in 2
It can be used in combination of two or more species.

Other copolymerizable vinyl monomers include ethyl acrylate, methyl acrylate, n-butyl acrylate, isobutyl acrylate, propyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate. , Unsaturated carboxylic acids such as methacrylic acid, ethyl methacrylic acid, methyl methacrylic acid, n-butyl methacrylic acid, isobutyl methacrylic acid, propyl methacrylic acid, 2-ethylhexyl methacrylic acid and stearyl methacrylic acid Examples thereof include esters, unsaturated dicarboxylic acid diesters such as dimethyl maleate, diethyl maleate, butyl maleate, dimethyl fumarate, diethyl fumarate, and dibutyl fumarate.

Further, unsaturated monocarboxylic acids such as acrylic acid, methacrylic acid and cinnamic acid, unsaturated dicarboxylic acids such as maleic acid, fumaric acid and itaconic acid, monomethyl maleate, monoethyl maleate, monobutyl maleate and fumaric acid. A carboxylic acid-containing vinyl monomer such as an unsaturated monocarboxylic acid monoester such as monomethyl, monoethyl fumarate or monobutyl fumarate may also be used in combination. The copolymerization ratio of these monomers is not particularly limited, but it is preferable to set the glass transition temperature of the obtained resin to a range of 50 ° C. or higher. This is because when the glass transition temperature of the resin is lower than 50 ° C., the storage stability may become extremely low when it is made into a toner.

The present invention is directed to polymerizing a high molecular weight polymer component by emulsion polymerization and polymerizing a low molecular weight polymer component by suspension polymerization in the presence of an emulsion of the high molecular weight polymer component. And a low molecular weight polymer component are uniformly mixed to produce a binder resin for toner. In the present invention, the emulsion polymerization of the high molecular weight polymer component is not particularly limited and can be performed according to a general emulsion polymerization method, and is generally used in the emulsion polymerization together with the monomer as described above. An emulsifier, a polymerization initiator or the like can be used.

Examples of emulsifiers used include fatty acid salts, alkyl sulfate ester salts, alkylbenzene sulfonates, alkylnaphthalene sulfonates, alkyl sulfosuccinates, alkyl diphenyl ether disulfonates, alkyl phosphates, and polyoxys. Ethylene alkyl sulfate ester salt, polyoxyethylene alkyl allyl sulfate ester salt, naphthalene sulfonic acid formalin condensate, special polycarboxylic acid type polymer surfactant, polyoxyethylene alkyl allyl ether, polyoxyethylene derivative, oxyethylene / oxypropylene Block polymer, sorbitan fatty acid ester, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene sorbitol fatty acid ester, glycerin fatty acid ester, polio Shiechiren fatty acid esters, polyoxyethylene alkyl amines, alkyl alkanol amides, alkyl amine salts, quaternary ammonium salts, alkyl betaines, and amine oxides, and the like,
Anionic surfactants are preferable from the viewpoint of uniform mixing of the high molecular weight polymer component and the low molecular weight polymer component.

These emulsifiers may be added so that the monomer for high molecular weight polymer is substantially emulsified and dispersed in water,
0.1 to 100 parts by weight of monomer for high molecular weight polymer
It is preferably used in the range of 2.5 parts by weight, more preferably 0.2 to 1.5 parts by weight. This is because if the amount of the emulsifier used is less than 0.1 parts by weight, the stability of polymerization tends to be poor and agglomerates tend to be generated. This is because there is a tendency for the environmental dependency of (3), especially the humidity resistance, to deteriorate.

In emulsion polymerization of the polymer component,
The ratio (M / W) of the amount (M) of the monomer for high molecular weight polymer and the amount (W) of water is set in the range of about 1/2 to 1/10, and an inert gas such as nitrogen is used. It is preferable that the reaction system is replaced.

The polymer component polymerized by emulsion polymerization has a weight average molecular weight (Mw) of 1 × 10 ^{5 to} 1.5.
It is preferably in the range of × 10 ⁶ . This is because when the weight average molecular weight (Mw) is less than 1 × 10 ⁵ , the non-offset property of the toner tends to decrease, and conversely 1.
This is because if it exceeds 5 × 10 ⁶ , the fixability as a toner tends to decrease.

In the present invention, the low molecular weight polymer component is polymerized by suspension polymerization in the presence of an emulsion of the emulsion polymerized high molecular weight polymer component. Suspension polymerization, after the high molecular weight polymer component, the monomer for low molecular weight polymer and the dispersant are sufficiently stirred and mixed, a polymerization initiator may be added to raise the temperature to carry out the polymerization. At this time, a toner was prepared by using a nonionic dispersant having a surface tension of a 0.2% aqueous solution at 20 ° C. of 55 dyne / cm or less.
It is possible to obtain a binder resin for toner, which is excellent in environmental dependency as a result, particularly excellent in moisture resistance. this is,
The surface tension of a 0.2% aqueous solution at 20 ° C is 55 dyne /
This is because the stability of suspension polymerization is reduced and aggregates are more likely to be generated in a nonionic dispersant having a particle size of more than 10 cm. This is because the environmental dependency, especially the humidity resistance is reduced.

Further, in the present invention, since the suspension polymerization of the low molecular weight polymer component is carried out in the presence of the emulsion of the high molecular weight polymer component, the use of the nonionic dispersant as the dispersant reduces the low molecular weight It is possible to prevent the high molecular weight polymer from being dissolved in the monomer for the polymer to increase the viscosity of oil droplets and decrease the polymerization stability.

As the nonionic dispersant used in the suspension polymerization of the low molecular weight polymer component of the present invention, polyvinyl alcohol, polyethylene oxide, methyl cellulose,
Examples thereof include ethyl cellulose and gelatin. Among them, polyvinyl alcohol is particularly preferable. Particularly, partially saponified polyvinyl alcohol in which an acetic acid group and a hydroxyl group are present in a block is preferable.

These nonionic dispersants are preferably used in the range of 0.1 to 1 part by weight based on 100 parts by weight of the total amount of the high molecular weight polymer component and the low molecular weight polymer component. This is because when the amount of the nonionic dispersant used is less than 0.1 part by weight, the stability of the suspension polymerization is lowered and the polymer tends to solidify due to the aggregation of the produced particles. This is because if the amount exceeds the range, the environmental dependency of the toner, particularly the moisture resistance tends to decrease, and more preferably 0.2 to
It is in the range of 0.8 parts by weight.

On the other hand, in the present invention, the nonionic dispersant is dividedly added before and after the addition of the low molecular weight polymer monomer, that is, the nonionic dispersant is added to the emulsion of the high molecular weight polymer component. After adding a part of the dispersant, the monomer for low molecular weight polymer is added, and by adding the remaining nonionic dispersant, the stability of suspension polymerization is improved and the nonionic It is possible to obtain a binder resin for a toner which can reduce the amount of the dispersant used and can improve the environmental dependency of the toner, particularly the moisture resistance.

The suspension polymerization of the low molecular weight polymer component is 1 to 10 times, preferably 2 to 10 times that of the low molecular weight polymer monomer.
About 4 times as much water, a dispersant, a polymerization initiator and, if necessary, a dispersion aid or a chain transfer agent are added, the temperature is raised to a predetermined polymerization temperature, and the polymerization is substantially completed. It is performed by continuing heating until the rate becomes 95% or more.

The low molecular weight polymer component polymerized by suspension polymerization has a weight average molecular weight (Mw) of 3 × 10 ³ to 8 ×.
It is preferably in the range of 10 ⁴ . This is because when the weight average molecular weight (Mw) is less than 3 × 10 ³ , the mechanical strength of the resin is lowered and the toner tends to be over-pulverized when electrification occurs, so that the image tends to be fogged. To 8
This is because if it exceeds × 10 ⁴ , the fixability as a toner tends to decrease.

In the present invention, the ratio of the high molecular weight polymer component to the low molecular weight polymer component is not particularly limited, but the high molecular weight polymer component is contained in the range of 10 to 50% by weight. It is preferable. This is because when the high molecular weight polymer component is less than 10% by weight, the non-offset property as a toner tends to be poor, and when it exceeds 50 parts by weight, the fixability as a toner tends to be poor. .

The polymerization initiator used in the present invention is not particularly limited, and commonly used radically polymerizable peroxides and azo compounds can be used, and examples thereof include potassium sulfate and sulfuric acid. Sodium, di-t
-Butyl peroxide, t-butyl cumyl peroxide, dicumyl peroxide, acetyl peroxide, isobutyryl peroxide, octanonyl peroxide,
Decanonyl peroxide, lauroyl peroxide,
3,5,5-trimethylhexanoyl peroxide, benzoyl peroxide, m-toluoyl peroxide,
t-butyl peroxyacetate, t-butyl peroxyisobutyrate, t-butyl peroxypiperate,
t-butyl peroxy neodecanoate, cumyl peroxy neodecanoate, t-butyl peroxy 2-ethylhexanoate, t-butyl peroxy 3,5,5-trimethylhexanoate, t-butyl peroxy lye Rate, t-butyl peroxybenzoate, t-butyl peroxyisopropyl cavonate, azobisisobutyl nitrile, 2,2-azobis- (2,4-dimethylvaleronitrile), and the like. Octanoyl peroxide, decanonyl peroxide, lauroyl peroxide, benzoyl peroxide, and m-trioyl peroxide are preferred from the viewpoint of the sustainability of the polymerization activity and the fact that the polymerization is completed in a relatively short time. These polymerization initiators can be used alone or in combination of two or more, and the amount is 0.1 to 100 parts by weight of the monomer.
It is also preferable to use 10 to 10 parts by weight, more preferably 0.5 to 10 parts by weight.

Further, in the present invention, in order to adjust the molecular weight, n-octyl mercaptan, if necessary,
Chain transfer agents such as n-dodecyl mercaptan, t-dodecyl mercaptan, 2-ethylhexyl thioglycolate, and α-methylstyrene dimer can also be used.

[0025]

EXAMPLES The present invention will be specifically described below with reference to examples. In the examples, the weight average molecular weight (Mw) is a value measured by gel permeation chromatography, using tetrahydrofuran as a solvent, and HC manufactured by Tosoh Corporation.
It measured using L-8020 and calculated | required by polystyrene conversion. Environmental dependency (humidity resistance): temperature 35 ° C, humidity 8
The difference between the charge amount after being left for about 24 hours under the environment of 5% and the charge amount after leaving for about 24 hours under the environment of the temperature of 20 ° C. and the humidity of 60% is calculated, and the difference is 3 μC / g. On the basis of the above, those below this were evaluated as good.

Example 1 120 parts by weight of deionized water, 0.06 part by weight of potassium sulfate, and 0.2 part by weight of sodium dodecylbenzene sulfonate (Neopex F-25 manufactured by Kao Corporation) were charged into a reaction vessel and completely Dissolve. Then, a monomer mixture consisting of 16.4 parts by weight of styrene and 3.6 parts by weight of n-butyl acrylate was charged, and nitrogen was introduced to replace nitrogen in the reaction vessel, and then in the presence of nitrogen. Emulsion polymerization was carried out at 70 ° C. for 3 hours to obtain a high molecular weight polymer component having a weight average molecular weight (Mw) of 9.8 × 10 ⁵ . Then, the temperature of the reaction system is set to 40
80% by weight of deionized water completely dissolved in 0.64 parts by weight of polyvinyl alcohol (PVA-224E manufactured by Kuraray Co., Ltd.) having a surface tension of 53% dyne / cm at 20 ° C. in a 0.2% aqueous solution. And styrene 66.4
A mixture of 1 part by weight, 13.6 parts by weight of n-butyl acrylate and 5.6 parts by weight of benzoyl peroxide was added and uniformly dispersed, and then polymerization was performed at 85 ° C. for 2 hours. Further, the temperature was raised to 95 ° C. and kept for 1 hour to complete the suspension polymerization. The weight average molecular weight (Mw) of the obtained low molecular weight polymer component was 2 × 10 ⁴ . Then, it was sufficiently washed with water and dried to obtain a styrene-acrylic toner binder resin in which a high molecular weight polymer component and a low molecular weight polymer component were uniformly mixed. Polymerization stability was good, and the obtained resin was also uniform particles.

The obtained resin (93 parts by weight), carbon black (4 parts by weight), negative charging caustic control agent (1% by weight) and polyolefin wax (2 parts by weight) were mixed and melt-kneaded at 145 ° C. Then, it was pulverized by using a jet mill fine pulverizer and classified to obtain a toner having an average particle diameter of 13 μm.
The obtained toner had good environmental dependence.

Example 2 120 parts by weight of deionized water, 0.06 part by weight of potassium sulfate, and 0.2 part by weight of sodium dodecylbenzene sulfonate (Neopex F-25 manufactured by Kao Co.) were charged into a reaction vessel and completely Dissolve. Then, a monomer mixture consisting of 16.4 parts by weight of styrene and 3.6 parts by weight of n-butyl acrylate was charged, and nitrogen was introduced to replace nitrogen in the reaction vessel, and then in the presence of nitrogen. Emulsion polymerization was carried out at 70 ° C. for 3 hours to obtain a high molecular weight polymer component having a weight average molecular weight (Mw) of 9.8 × 10 ⁵ . Then, the temperature of the reaction system is set to 40
40 parts by weight of deionized water in which 0.24 parts by weight of polyvinyl alcohol (PVA-224E manufactured by Kuraray Co., Ltd.) having a surface tension at 20 ° C. of a 0.2% aqueous solution was completely dissolved. And styrene 66.4
A mixture of 1 part by weight, 13.6 parts by weight of n-butyl acrylate and 5.6 parts by weight of benzoyl peroxide was added. Furthermore, 40 parts by weight of deionized water in which 0.24 parts by weight of polyvinyl alcohol (PVA-224E manufactured by Kuraray Co., Ltd.) having a surface tension of a 0.2% aqueous solution at 20 ° C. of 53 dyne / cm was added, After being uniformly dispersed, polymerization was carried out at 85 ° C. for 2 hours. Further, the temperature was raised to 95 ° C. and kept for 1 hour to complete the suspension polymerization. The weight average molecular weight (Mw) of the obtained low molecular weight polymer component was 2 ×
It was 10 ⁴ . After that, thoroughly wash with water and dry,
A binder resin for a styrene-acrylic toner in which a high molecular weight polymer component and a low molecular weight polymer component were uniformly mixed was obtained. Polymerization stability was extremely good, and the obtained resin was also uniform particles.

93 parts by weight of the obtained resin, 4 parts by weight of carbon black, 1% by weight of a negative charging caustic control agent and 2 parts by weight of a polyolefin wax were mixed and melt-kneaded at 145.degree. Then, it was pulverized by using a jet mill fine pulverizer and classified to obtain a toner having an average particle diameter of 13 μm.
The environment dependency of the obtained toner was extremely good.

Example 3 120 parts by weight of deionized water, 0.06 part by weight of potassium sulfate, and 0.2 part by weight of sodium dodecylbenzene sulfonate (Neopex F-25 manufactured by Kao Co.) were charged into a reaction vessel and completely Dissolve. Then, a monomer mixture consisting of 16.4 parts by weight of styrene and 3.6 parts by weight of n-butyl acrylate was charged, and nitrogen was introduced to replace nitrogen in the reaction vessel, and then in the presence of nitrogen. Emulsion polymerization was carried out at 70 ° C. for 3 hours to obtain a high molecular weight polymer component having a weight average molecular weight (Mw) of 9.8 × 10 ⁵ . Then, the temperature of the reaction system is set to 40
40% deionized water which was cooled to 0 ° C. and completely dissolved 0.48 parts by weight of polyvinyl alcohol (PVA-217 manufactured by Kuraray Co., Ltd.) having a surface tension of 55.5 dyne / cm of a 0.2% aqueous solution at 20 ° C. Add parts by weight of styrene 66.
A mixture of 4 parts by weight, 13.6 parts by weight of n-butyl acrylate and 5.6 parts by weight of benzoyl peroxide was added and uniformly dispersed, and then polymerization was carried out at 85 ° C. for 2 hours. Further, the temperature was raised to 95 ° C. and kept for 1 hour to complete the suspension polymerization. The weight average molecular weight (Mw) of the obtained low molecular weight polymer component was 2 × 10 ⁴ . Then, it was sufficiently washed with water and dried to obtain a styrene-acrylic toner binder resin in which a high molecular weight polymer component and a low molecular weight polymer component were uniformly mixed. Polymerization stability was good, and the obtained resin was also uniform particles.

The obtained resin (93 parts by weight), carbon black (4 parts by weight), negative charging caustic control agent (1% by weight) and polyolefin wax (2 parts by weight) were mixed and melt-kneaded at 145 ° C. Then, it was pulverized by using a jet mill fine pulverizer and classified to obtain a toner having an average particle diameter of 13 μm.
The obtained toner was slightly inferior to the environment, but practically no problem.

Comparative Example 1 120 parts by weight of deionized water, 0.06 part by weight of potassium sulfate, and 0.2 part by weight of sodium dodecylbenzene sulfonate (Neopex F-25 manufactured by Kao Co.) were charged into a reaction vessel and completely. Dissolve. Then, a monomer mixture consisting of 16.4 parts by weight of styrene and 3.6 parts by weight of n-butyl acrylate was charged, and nitrogen was introduced to replace nitrogen in the reaction vessel, and then in the presence of nitrogen. Emulsion polymerization was carried out at 70 ° C. for 3 hours to salt out the emulsion to obtain a high molecular weight polymer component having a weight average molecular weight (Mw) of 9.8 × 10 ⁵ .
On the other hand, the surface tension of a 0.2% aqueous solution at 20 ° C is 53 dy.
ne / cm polyvinyl alcohol (Kuraray PVA
-224E) 0.48 parts by weight of completely dissolved 160 parts by weight of deionized water was added, and 66.4 parts by weight of styrene,
A mixture of 13.6 parts by weight of n-butyl acrylate and 5.6 parts by weight of benzoyl peroxide was added,
After being uniformly dispersed, polymerization was carried out at 85 ° C. for 2 hours. Further, the temperature was raised to 95 ° C. and kept for 1 hour to complete the suspension polymerization. The weight average molecular weight (Mw) of the obtained low molecular weight polymer component was 2 × 10 ⁴ .

The obtained high molecular weight polymer component and low molecular weight polymer component were melt-kneaded at 145 ° C., but a uniform mixture could not be obtained.

Comparative Example 2 120 parts by weight of deionized water, 0.06 part by weight of potassium sulfate and 0.2 part by weight of sodium dodecylbenzene sulfonate (Neopex F-25 manufactured by Kao Co.) were charged into a reaction vessel and completely. Dissolve. Then, a monomer mixture consisting of 16.4 parts by weight of styrene and 3.6 parts by weight of n-butyl acrylate was charged, and nitrogen was introduced to replace nitrogen in the reaction vessel, and then in the presence of nitrogen. Emulsion polymerization was carried out at 70 ° C. for 3 hours to obtain a high molecular weight polymer component having a weight average molecular weight (Mw) of 9.8 × 10 ⁵ . Then, the temperature of the reaction system is set to 40
Deionized water 80, which was cooled to 0 ° C and completely dissolved 0.64 parts by weight of polyvinyl alcohol (PVA-217 manufactured by Kuraray Co., Ltd.) having a surface tension of 55.5 dyne / cm of a 0.2% aqueous solution at 20 ° C. Add parts by weight of styrene 66.
A mixture of 4 parts by weight, 13.6 parts by weight of n-butyl acrylate and 5.6 parts by weight of benzoyl peroxide was added and uniformly dispersed, and then suspension polymerization was carried out at 85 ° C. The stability was decreased and it solidified into a sticky shape after 1 hour.

Comparative Example 3 120 parts by weight of deionized water, 0.06 part by weight of potassium sulfate, and 0.2 part by weight of sodium dodecylbenzene sulfonate (Neopex F-25 manufactured by Kao Co.) were charged into a reaction vessel and completely. Dissolve. Then, a monomer mixture consisting of 16.4 parts by weight of styrene and 3.6 parts by weight of n-butyl acrylate was charged, and nitrogen was introduced to replace nitrogen in the reaction vessel, and then in the presence of nitrogen. Emulsion polymerization was carried out at 70 ° C. for 3 hours to obtain a high molecular weight polymer component having a weight average molecular weight (Mw) of 9.8 × 10 ⁵ . Then, the temperature of the reaction system is set to 40
Deionized water 80 which was cooled to 0 ° C. and completely dissolved 1.5 parts by weight of polyvinyl alcohol (PVA-217 manufactured by Kuraray Co., Ltd.) having a surface tension of 55.5 dyne / cm of a 0.2% aqueous solution at 20 ° C. Styrene 66.4
A body mixture consisting of 1 part by weight, 13.6 parts by weight of n-butyl acrylate and 5.6 parts by weight of benzoyl peroxide was added and uniformly dispersed, followed by polymerization at 85 ° C. for 2 hours. Then, the temperature was raised to 95 ° C. and maintained for 1 hour to complete the suspension polymerization. The weight average molecular weight (Mw) of the obtained low molecular weight polymer component was 2 × 10 ⁴ . afterwards,
The resin was thoroughly washed with water and dried to obtain a styrene-acrylic toner binder resin in which a high molecular weight polymer component and a low molecular weight polymer component were uniformly mixed. Polymerization stability was good, and the obtained resin was also non-uniform particles.

93 parts by weight of the obtained resin, 4 parts by weight of carbon black, 1% by weight of a negative charging caustic control agent and 2 parts by weight of a polyolefin wax were mixed and melt-kneaded at 145.degree. Then, it was pulverized by using a jet mill fine pulverizer and classified to obtain a toner having an average particle diameter of 13 μm.
The obtained toner had poor environmental dependence.

[0037]

The method for producing a binder resin for a toner according to the present invention is carried out by carrying out suspension polymerization of a low molecular weight polymer component using a nonionic dispersant having a specific surface tension. A toner in which a high-molecular weight polymer and a low-molecular weight polymer are uniformly mixed by dividingly adding a nonionic dispersant in the suspension polymerization of the combined component.
It is possible to provide a binder resin for use, a toner excellent in environmental dependency, particularly excellent in moisture resistance.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoko Harada 2-1, 4-1, Ushikawa-dori, Toyohashi-shi, Aichi Sanryo Rayon Co., Ltd. Toyohashi Plant (72) Hiromi Kobayashi 4-chome, Ushikawa-dori, Toyohashi-shi, Aichi Address 2 Sanryo Rayon Co., Ltd. Toyohashi Plant

Claims (2)

[Claims] 1. After polymerizing a high molecular weight polymer component by an emulsion polymerization method, the surface tension of a 0.2% aqueous solution at 20 ° C. is 55 dyne / cm or less in the presence of an emulsion of the high molecular weight polymer component. A method for producing a binder resin for a toner, which comprises polymerizing a low molecular weight polymer component by suspension polymerization using a certain nonionic dispersant. 2. A low molecular weight polymer for polymerizing a high molecular weight polymer component by an emulsion polymerization method and then suspension polymerizing the low molecular weight polymer component in the presence of an emulsion of the high molecular weight polymer component. A method for producing a binder resin for toner, characterized in that the nonionic dispersant is dividedly added before and after the addition of the monomer.