JP2832574B2 - Method for producing polymerized toner - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a polymerized toner produced by suspension polymerization.

[0002]

2. Description of the Related Art Conventionally, toners used in electrophotography and the like are prepared by melting and kneading a binder resin, a colorant, a charge control agent, and the like.
It was manufactured by a so-called pulverization method of pulverizing and classifying. The toner produced by this pulverization method had an average particle size of about 10 to 20 μm. In recent years, in electronic copiers, colorization, high definition, and high image quality have been pursued, and accordingly, there has been a long-awaited demand for toner having a small particle diameter having an average particle diameter of 10 μm or less. However, it has been difficult to produce a small-particle-diameter toner with a high yield by the pulverization method. In order to solve such a problem of the pulverizing method, a toner is produced from a polymerizable monomer by a suspension polymerization method. When a toner is obtained by a suspension polymerization method, a monomer composition (oil phase) containing at least a polymerizable monomer and a colorant, mainly carbon black and a charge control agent, is mixed with a water-miscible medium (aqueous phase). ), Granulation (granulation step) to the particle size of the toner using a suitable stirrer, and occurs when a polymerization initiator added in advance or a newly added polymerization initiator is decomposed by heat. The polymerizable monomer is polymerized by radicals to form a polymer (polymerization step), thereby producing a polymerized toner. Since the shape of the polymerized toner obtained by this suspension polymerization method is spherical, the polymerized toner has characteristics such as excellent fluidity. However, this suspension polymerization method also has problems. That is, in the conventional suspension polymerization method, the charge control agent is mixed in the oil phase together with the polymerizable monomer, and the granulation step and the polymerization step are performed. Therefore, the surface of the polymer particles is covered with the resin component. For this reason, the charge control agent was not exposed on the surface of the particles, and thus polymer particles having a problem in triboelectricity were produced. That is, such polymer particles do not have a large amount of triboelectric charge of the polymerized toner in a short time when mixed with the carrier in practical use, or toner particles having an uneven distribution of triboelectric charge of individual toner particles. The toner particles having the opposite polarity. The toner particles are scattered inside the copying machine, causing a background fog in a blank portion of the transfer paper, or causing a problem that the inside of the copying machine is contaminated (hereinafter referred to as toner scattering).

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for producing a polymerized toner capable of obtaining toner particles having a rapid rise of the triboelectric charge amount and a uniform triboelectric charge distribution upon friction with a carrier or the like. Is to do.

[0004]

Means for Solving the Problems The present inventors have conducted intensive studies to solve the problems of the prior art,
After dispersing the charge control agent in the aqueous phase, by performing the oil phase granulation step, the charge control agent is uniformly fixed on the toner particle surface, thereby producing toner particles with a sufficient triboelectric charge amount, and It has been found that the amount of triboelectric charge of the toner particles can be easily controlled by changing the amount of the charge control agent added to the aqueous phase. That is, the method according to claim 1 of the present invention, an aqueous phase electric load control agent is dispersed, at least a polymerizable monomer, an oil phase obtained by dispersing a colorant and a polymerization initiator, A step of continuously supplying the both to a granulator at a controlled ratio through independent paths while maintaining them in independent tanks to obtain a suspension having a polymerizable droplet group having a desired size. And taking out the suspension from the granulator and introducing the suspension into a polymerization tank to complete the polymerization reaction to obtain polymer particles. The method according to claim 3 of the present invention provides an oil obtained by dispersing an aqueous phase in which a charge control agent and a suspension stabilizer are dispersed, and at least a polymerizable monomer, a colorant, and a polymerization initiator. And the two phases are continuously supplied to the granulator at a controlled ratio through independent paths, and a suspension having polymerizable droplet groups of a desired size is provided. A step of obtaining a liquid, and a step of taking out the suspension from the granulator, guiding the suspension into a polymerization tank to complete the polymerization reaction, and obtaining polymer particles. is there.

Hereinafter, the present invention will be described in detail. In the present invention, first, an aqueous phase in which a charge control agent is dispersed is obtained. Examples of the charge control agent used in the present invention include a metal complex of a carboxyl group, a sulfonic acid ester or an organic compound having a nitrogen-containing group, or a carboxyl group, a metal-containing dye of an organic compound having a sulfonic acid ester or a nitrogen-containing group, or the like. Sulfonic acid and its salt in the main chain or side chain,
Polymer compounds having a polar functional group such as quaternary ammonium salts can be mentioned. Among them, a metal complex of an organic compound having a carboxyl group, a sulfonic acid ester or a nitrogen-containing group, or a metal-containing dye of an organic compound having a carboxyl group, a sulfonic acid ester or a nitrogen-containing group is favorably and uniformly fixed on the toner particle surface. Is preferred. These charge control agents may be used alone or in combination of two or more. The addition amount of the charge control agent in the aqueous phase is 0.1 to 1 with respect to 100 parts by weight of the polymerizable monomer in consideration of the triboelectrification property of the polymerized toner, economy, and fixing property of the polymerized toner.
0 parts by weight is preferable, and particularly 0.5 to 5 parts by weight is preferable. If the amount is less than 0.1 part by weight, it is difficult to obtain good developing characteristics due to a small amount of triboelectric charge, and the charge amount distribution of the entire polymerized toner tends to be non-uniform. , And as a result, it is uneconomical to consume a charge control agent which is more expensive than necessary.

The suspension stabilizer used in the present invention includes a water-soluble polymer having a hydrophilic group and a hydrophobic group in its molecule, for example, polyvinyl alcohol, casein,
Examples include cellulose derivatives such as gelatin, methylcellulose, methylhydroxypropylcellulose, and ethylcellulose, starch and derivatives thereof, poly (meth) acrylic acid and salts thereof, and solid fine powder. As solid fine powder, for example, tricalcium phosphate and calcium carbonate, metal fine powder such as copper and iron, silica,
Alumina and the like can be mentioned. Among such suspension stabilizers, solid fine powders are preferred because they are insoluble in water and relatively stable when heated. Particularly, tribasic calcium phosphate and calcium carbonate are polymerizable monomers dispersed in an oil phase. It is preferable because a polymerized toner having a uniform particle size can be obtained irrespective of the type, amount and properties of the monomer, colorant, magnetic powder and the like. These suspension stabilizers may be used alone or in combination of two or more. The addition amount of the suspension stabilizer in the aqueous phase is preferably 0.5 to 20 parts by weight based on 100 parts by weight of water in the aqueous phase. If the amount is less than 0.5 part by weight, it is difficult to obtain a polymerized toner having a small particle size of 10 μm or less. On the other hand, if the amount is more than 20 parts by weight, the viscosity of the aqueous phase increases, and it is difficult to obtain a polymerized toner having a small particle size, and it is difficult to obtain a polymerized toner having a uniform particle size. Such a suspension stabilizer adheres to the surface of a monomer composition composed of a polymerizable monomer and a colorant in an oil phase, and has an effect of forming the monomer composition into uniform particles. At the same time, it has an action of adhering the charge control agent to the surface of the particles composed of the monomer composition. The suspension stabilizer composed of tricalcium phosphate and calcium carbonate can be obtained by obtaining polymer particles in an aqueous phase, washing with an acid, and removing the polymer particles from the surface of the polymer particles. This is preferable because the property is improved.

Further, in order to stabilize the monomer composition suspended in the aqueous phase and obtain a polymerized toner having uniform particles, an interface between sodium dodecylsulfonate and sodium dodecylbenzenesulfonate as a suspending aid is used. Preferably, an activator is added to the aqueous phase. The amount of the suspension aid added is 100
0.005 to 0.05 parts by weight based on parts by weight is preferred.

Next, the oil phase will be described. The oil phase constituting the present invention is one in which at least a polymerizable monomer, a colorant and a polymerization initiator are dispersed. As the monomer composition used in the present invention, for example, polymerizable monomers as described below can be used. That is, as the polymerizable monomer, for example, styrene, o-methylstyrene, m-methylstyrene, p-methylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, 3,4-dichlorostyrene , P-ethylstyrene, 2,4-dimethylstyrene, pn-butylstyrene, p-tert-butylstyrene, pn-hexylstyrene, pn-octylstyrene, pn-nonylstyrene, p- Styrene and derivatives thereof such as n-decylstyrene; ethylene unsaturated monoolefins such as ethylene, propylene, butylene and isobutylene; vinyl halides such as vinyl chloride, vinylidene chloride, vinyl bromide and vinyl fluoride; Organic acid vinyl esters such as vinyl acetate, vinyl propionate and vinyl benzoate;
Methacrylic acid, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate,
Methacrylic acid such as n-octyl methacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, and the like; acrylic acid, methyl acrylate, Ethyl acrylate, n-butyl acrylate, isobutyl acrylate, propyl acrylate, n-acrylate
-Acrylic acid and its derivatives such as octyl, dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate and phenyl acrylate; vinyl ethers such as vinyl methyl ether, vinyl ethyl ether and vinyl isobutyl ether Vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone, vinyl isopropenyl ketone; N-vinyl compounds such as N-vinyl pyrrole, N-vinyl carbazole, N-vinyl indole, N-vinyl pyrrolidone; vinyl naphthalenes; Polymerizable monomers such as acrylonitrile, methacrylonitrile, acrylamide and the like can be mentioned, and they may be used alone or as a mixture depending on the purpose. Among the above polymerizable monomers, it is preferable to use styrene or a styrene derivative alone or in a mixture with methacrylic acid and its derivatives or acrylic acid and its derivatives, from the viewpoint of improving the developing characteristics and durability of the polymerized toner.

The coloring agent used in the present invention is
Bon Black is suitable. That is, as the carbon black used in the present invention, a number average particle size,
It can be used without any limitation on oil absorption, pH, etc., but the following are commercially available products. For example, Regal 400, 660, 330, 30 manufactured by Cabot Corporation, USA
0, SRF-S, STELLING S
O, V, NS, R; Raven H20, MT-P, 410, 42 manufactured by Columbia Carbon Japan, Inc.
0, 430, 450, 500, 760, 780, 100
0, 1035, 1060, 1080; # 10B, # 5B, # 40, # 2400B, MA-10 manufactured by Mitsubishi Chemical Corporation
0; and the like. These carbon blacks may be used alone or in combination of two or more with various compositions. As the colorant other than carbon black, a colorant that can be dispersed in the monomer composition and that exhibits a color that is clear and has excellent stability over time when used as a toner is used. Examples of such colorants include phthalocyanine pigments, rhodamine lake pigments, azo lake pigments, iron oxide, titanium oxide, alumina, barium sulfate, and the like. The colorant is used in an amount of 1 to 40 parts by weight, preferably 3 to 20 parts by weight, based on 100 parts by weight of the polymerizable monomer.

[0010] The polymerization initiator used in the present invention is preferably soluble in a polymerizable monomer. Examples of such a polymerization initiator include 2,2′-azobisvaleronitrile, 2,2′-azobisisobutyronitrile,
2,2′-azobis- (2,4-dimethylvaleronitrile), 2,2′-azobis-4-methoxy-2,4-dimethylvaleronitrile, other azo or diazo polymerization initiators; benzoyl peroxide , Methyl ethyl ketone peroxide, isopropyl peroxycarbonate, and other peroxide-based polymerization initiators. However, benzoyl peroxide-based polymerization initiators and the like may decompose and produce carboxylic acids such as benzoic acid as a by-product, which may adversely affect the storage stability of the toner, and also have disadvantages such as generation of an aromatic odor. Therefore, it is preferable to use an azo-based polymerization initiator. In the present invention,
For the purpose of controlling the molecular weight and the molecular weight distribution or controlling the reaction time, it is preferable to use two or more of the above-mentioned polymerization initiators in combination with various compositions. Further, a water-soluble initiator such as ammonium persulfate and potassium persulfate may be used in combination, if necessary. The amount of the polymerization initiator to be used is generally 0.1 to 20 parts by weight, preferably 1 to 10 parts by weight, based on 100 parts by weight of the polymerizable monomer. When the amount of the polymerization initiator is less than 0.1 part by weight, the polymerization time may be long, and the molecular weight of the polymerization toner may be too high. On the other hand, if the polymerization initiator exceeds 20 parts by weight, the molecular weight of the polymerized toner may be too low, which is not preferable. Furthermore, in the oil phase in the present invention, for the purpose of improving blocking resistance and durability in the toner,
There is no problem even if a crosslinking agent for the polymer of the polymerizable monomer is added. As such a crosslinking agent, a crosslinking agent such as divinylbenzene can be added to the monomer composition.

In order to carry out the method according to the first aspect of the present invention using the above-mentioned materials, the following is carried out. Sand
Chi, an aqueous phase electric load control agent is dispersed, at least a polymerizable monomer, an oil phase obtained by dispersing a colorant and a polymerization initiator, and held to each separate tank and were each independently Supplying the both continuously to the granulator at a controlled ratio through the path to obtain a suspension having a group of polymerizable droplets of a desired size; and This is a production method in which the polymer particles are taken out and guided into a polymerization tank to complete the polymerization reaction to obtain polymer particles. Further, the invention described in claim 3 of the present invention,
According to the first aspect of the present invention, a suspension stabilizer is added to the aqueous phase. These inventions will be specifically described with reference to the drawings (FIGS. 1 and 2). First, as shown in FIG. 1, an aqueous phase tank 1 containing an aqueous phase in which a charge control agent is dispersed, or an aqueous phase in which a charge control agent and a suspension stabilizer are dispersed, and a polymerizable monomer. The oil phase tank 2 containing the oil phase as the main component and the metering pumps 4 and 4, respectively.
At the same time, is introduced into the granulator 5 at a constant ratio, and is discharged as a suspension by applying a shearing force to the polymerization tank 3 provided with the condenser 6. The necessary heating is carried out by a heating jacket 7 provided around the periphery to complete the polymerization reaction, thereby producing polymer particles having a small particle diameter and a uniform particle size distribution. An example of the granulator 5 used in the present invention is as shown in FIG. 2, and the granulator 5 has an oil phase supply port 14 and an aqueous phase supply port 13, and both liquids are in a shear region. Enter 11. The stirring blade 10 is fixed to the shearing region 11 by the rotating shaft 8. The stirring blade 10 is rotated by the rotation shaft 8 and generates a suspension in the shearing region 11 by the shearing force. A discharge regulating gap 12 is provided at the edge of the shearing region 11, and the dispersion (suspension) passing through this gap is discharged from the upper dispersion discharge port 9 and guided to the polymerization tank 3. It is supposed to be.

All suspension polymerizations in the present invention are generally
The polymerization is performed at a polymerization temperature of 50 ° C. or higher, and the temperature is set in consideration of the decomposition temperature of the polymerization initiator. If the set temperature is too high, the polymerization initiator is rapidly decomposed, which affects the molecular weight and the like, which is not preferable.

In the present invention, when obtaining a magnetic toner,
The polymerized toner is obtained by dispersing the magnetic substance in the oil phase. The magnetic substance is a substance which is strongly magnetized in the direction by a magnetic field, and is preferably black, can be dispersed well in a polymerizable monomer, is chemically stable, and is preferably 1 μm or less. Examples of such a magnetic material include metals such as cobalt, iron and nickel; alloys of metals such as aluminum, cobalt, copper, iron, magnesium and nickel, and mixtures thereof; nitrides such as vanadium nitride; And ferrites; mixtures thereof, and the like. The polymerized toner obtained by the present invention is used as a two-component developer by being mixed with a carrier, or used alone as a one-component developer without being mixed with a carrier in the case of a magnetic toner.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be specifically described below based on embodiments. In addition, all parts of the mixing ratio are parts by weight. <Example 1> 5 parts of carbon black (trade name: # 40, manufactured by Mitsubishi Kasei Kogyo Co., Ltd.) in a polymerizable monomer composed of 80 parts of styrene and 20 parts of n-butyl acrylate, 2,2'-azobis Valeronitrile (5 parts) was added, and carbon black was dispersed in the polymerizable monomer using an ultrasonic cleaner to prepare an oil phase. Next, 3 parts of tricalcium phosphate, 0.5 part of a charge controlling agent (trade name: T-77, manufactured by Hodogaya Chemical Industry Co., Ltd.) composed of a metal complex of an organic compound having a nitrogen-containing group, and 0.5 parts of sodium dodecylbenzenesulfonate After dispersing .05 parts in a small amount of water, it was added to 240 parts of water to prepare an aqueous phase.
And the oil phase are stored in the aqueous phase tank 1 and the oil phase tank 2 shown in FIG.
Was. Next, the water phase was flowed at a flow rate of 300 ml / min,
The mixture was supplied to the granulator 5 at a flow rate of 0 ml / min for 10 minutes . Granulation
The machine 5 has a rotating part with a diameter of 50 mm,
A liquid mixture of the water phase and the oil phase under the condition of 15000 rpm
Was stirred. The dispersion passed through the granulator 5 is converted into a turbine type
The polymerization tank shown in Fig. 1 while stirring at 300 rpm with a stirring blade
3 and reacted for 8 hours to obtain polymer particles. Above
After cooling the obtained polymer particles, the surface of the polymer particles is diluted with dilute nitric acid.
Remove tribasic calcium phosphate and make the washing solution neutral with water
After washing, filtration and drying, the polymerization
Got a ner.

<Comparative Example 1> 60 g of the oil phase and 240 g of the aqueous phase obtained in Example 1 were
Add to the separable flask of the bottle and add TK homogenizer at room temperature.
10,000 rpm using Kisa (manufactured by Tokushu Kika Kogyo Co., Ltd.)
For 1 minute. Then, the droplets are stirred to such an extent that the droplets do not settle.
While stirring, a monomer composition was formed at 80 ° C. for 5 hours.
Granulated and polymerized. Cool the polymer particles obtained above
Then, dilute nitric acid is used to remove tribasic calcium phosphate on the polymer particle surface.
After washing with washing water until the washing solution becomes neutral and filtering,
It was dried to obtain a polymerized toner for comparison.

Comparative Example 2 Comparative Example 1 was repeated in the same manner as in Comparative Example 1 , except that 0.5 part of the charge control agent was added to the oil phase instead of the aqueous phase, and then granulation was performed together with the aqueous phase. Polymerized toner was obtained.

Next, 5 parts of each of the polymerized toners of Example 1 and Comparative Example 2 obtained above and 95 parts of a carrier (trade name: DFC-200 S-3, manufactured by Dowa Iron Powder Co., Ltd.) were used in a V blender. Then, the mixture was stirred and mixed at 60 rpm. In this case, when the stirring time is 0.5 minutes, 1 minute, 1.5 minutes, 2 minutes, 5 minutes, and 10 minutes, a blow-off charge amount measuring device (manufactured by Toshiba Chemical Corporation)
The triboelectric charge amount of the polymerized toner was measured, and the transition of the triboelectric charge amount per unit time of the polymerized toner was evaluated. The results are shown in FIG . As is clear from FIG. 3, it was confirmed that the amount of triboelectric charge of the polymerized toner of Example 1 increased in a short time, and the rise of the triboelectric charge was fast. On the other hand, it was confirmed that the amount of triboelectric charge of the polymerized toner of Comparative Example 2 did not increase in a short time, and the rise of triboelectric charge was inferior.

Further, Example 1 obtained in the above , Comparative Example 1 and
5 parts of each polymerized toner of Comparative Example 2 and 95 parts of a carrier (trade name: DFC-200 S-3, manufactured by Dowa Iron Powder Co., Ltd.)
Using a blender, the mixture was stirred and mixed at 60 rpm for 30 minutes to prepare a developer . Next , the charge amount distribution of the polymerized toner in each developer obtained above was measured using a charge amount distribution meter (trade name, manufactured by PES).
q-MATER), and the results are shown in FIGS . As is clear from FIGS. 4 to 6, the charge amount distribution of the polymerized toner of Example 1 is such that all toner particles have a negative chargeability, the distribution is sharp, and the distribution of the triboelectric charge amount is uniform. It was confirmed that many toner particles were present. On the other hand, the charge amount distribution of the polymerized toner of Comparative Example 1 was
The charge amount distribution of the polymerized toner of Comparative Example 2 was broader than that of Example 1 , and it was confirmed that toner particles having positive chargeability were partially present and the distribution was broad.
Was.

Further, the polymerized toner 5 of Example 1 obtained above was obtained.
Section and carrier (trade name: DFC-20 manufactured by Dowa Iron Powder Industry Co., Ltd.)
0 S-3) 95 parts and 60 rpm using a V blender
m for 30 minutes to prepare a developer, and then use the developer to prepare a commercially available copying machine (trade name: JX, manufactured by Sharp Corporation).
-9700), continuous copying up to 10,000 sheets was performed. As a result, it was confirmed that practically satisfactory developing characteristics having sufficient image density without problems such as background fogging and toner scattering were obtained.

[0020]

According to the present invention, a polymerized toner having a rapid rise in the triboelectric charge amount can be obtained, and toner particles having a sharp triboelectric charge distribution and insufficient triboelectric charge amount and toner particles having the opposite polarity can be produced. A difficult polymerized toner can be obtained. Therefore, a polymerized toner having excellent development characteristics as an electrophotographic toner free from problems such as background fogging and toner scattering can be obtained.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing an example of a polymerization apparatus used in the present invention.

FIG. 2 is an explanatory view showing an example of a granulator used in the present invention.

FIG. 3 is a diagram showing a change in a triboelectric charge amount of a polymerized toner in Example 1 and Comparative Example 2 .

FIG. 4 shows a charge amount distribution of a polymerized toner in Example 1 .
FIG.

5 is a diagram showing a charge distribution of polymerized toner definitive in Comparative Example 1.

6 is a diagram showing a charge distribution of polymerized toner definitive in Comparative Example 2.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Water phase tank 2 Oil phase tank 3 Polymerization tank 4 Metering pump 5 Granulator 6 Condenser 7 Heating jacket 8 Rotating shaft 9 Dispersion liquid discharge port 10 Stirrer blade 11 Shear area 12 Discharge regulation gap 13 Water phase supply port 14 Oil phase supply port

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) G03G 9/08

Claims (6)

(57) [Claims] 1. An aqueous phase in which a charge control agent is dispersed, and an oil phase obtained by dispersing at least a polymerizable monomer, a colorant and a polymerization initiator, are held in independent tanks, respectively. Supplying the two continuously to the granulator at a controlled ratio through independent paths to obtain a suspension having a group of polymerizable droplets of a desired size; and Removing the liquid and introducing it into a polymerization tank to complete the polymerization reaction to obtain polymer particles. 2. The method according to claim 1, wherein the charge controlling agent is a metal complex of an organic compound having a carboxyl group, a sulfonic acid ester or a nitrogen-containing group, or a metal-containing dye of an organic compound having a carboxyl group, a sulfonic acid ester or a nitrogen-containing group. The method for producing a polymerized toner according to claim 1, wherein: 3. An aqueous phase in which a charge control agent and a suspension stabilizer are dispersed, and an oil phase obtained by dispersing at least a polymerizable monomer, a colorant and a polymerization initiator, in separate tanks. Hold and
And a step of continuously supplying both to a granulator at a controlled ratio through independent paths to obtain a suspension having a polymerizable droplet group of a desired size; and Removing the suspension and introducing the suspension into a polymerization tank to complete the polymerization reaction to obtain polymer particles. 4. The method according to claim 1, wherein the charge control agent is a metal complex of an organic compound having a carboxyl group, a sulfonic acid ester or a nitrogen-containing group, or a metal-containing dye of an organic compound having a carboxyl group, a sulfonic acid ester or a nitrogen-containing group. The method for producing a polymerized toner according to claim 3, wherein: 5. The method according to claim 3 , wherein the suspension stabilizer is a fine solid powder. 6. The method according to claim 5, wherein the solid fine powder is tribasic calcium phosphate or calcium carbonate.