JPS63165869A - Production of electrostatic charge image developing toner - Google Patents

Abstract

PURPOSE:To improve grain forming efficiency by forming grains by means of two or more stirring devices with high shearing force arranged in a grain forming container at the time of forming grains. CONSTITUTION:In the stirring device 1 with high shearing force, a dispersed solution consisting of a monomer component and a liquid dispersed medium is injected from an injection port 6 into the device 1. The solution 6 is stirred by strong searing force, shock and a turbulent flow generated between a rapidly rotating turbine 2 and a stator 3 and monomer component grains in micron order are formed and flow out from a dispersed solution outflow port 4a. In the grain forming process, the monomer component is grained on the basis of the action of two or more devices 1 under the existence of a dispersion stabilizer. In this case, the grain forming efficiency can be improved by the synergetic effect of the shock of dispersed solutions flowing out from respective stirring devices 1 and complex turbulent flows generated around respective stirring devices 1.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing toner for developing electrostatic images in image forming methods such as electrophotography, electrostatic photography, and electrostatic printing. The present invention relates to a method for producing a toner for developing electrostatic images by an improved suspension polymerization method, which includes a granulation step for efficiently forming particles with a sharp particle size distribution.

i1 Wataru 1 Conventionally, methods for developing electrostatic images formed on a recording medium in electrophotography, electrostatic recording, or electrostatic printing are broadly divided into methods using various pigments and dyes in an insulating liquid. A liquid development method using a developer made by dispersing , a cascade method using fine particles called a toner made of a natural or synthetic polymer or wax containing a colorant such as carbon black dispersed therein, a bristle brush method, There are so-called dry developing methods such as a magnetic brush method, an impression method, and a powder cloud method.

In the liquid developing method, processing of the developer is troublesome, and there are problems such as the generation of a unique unpleasant odor during and after the development and fixing process. Therefore, the dry developing method using the toner is mainly used in practical use. ing.

The toner for developing electrostatic images used in the dry development method is usually
For example, a binder made of a vinyl polymer such as polystyrene or polyacrylic acid ester, an epoxy polymer, a petroleum polymer, an ester condensate, etc., and a coloring agent such as carbon black are mixed, melted and kneaded, It is manufactured by cooling, pulverizing, and further classifying the toner particles to have a particle size of 1 to 50 μm. The toner formed in this way has, for example, storage stability, durability, moisture resistance, electrostatic properties,
It is required to satisfy timekeeping properties such as fluidity, fixing properties, and image quality.

Forming toner by the above-mentioned manufacturing method called the so-called pulverization method has many advantages, and it is said that most of the dry toners currently on the market are manufactured by this pulverization method.

However, this method has many problems. In other words, in the pulverization method, the wind-powered collision type pulverizer that is used for the main part of the pulverization process uses a large amount of compressed air, which requires a large amount of equipment cost and consumes electricity during operation. Therefore, these costs account for most of the toner processing cost. In particular, in recent years, there has been a demand for toner with a sharp particle size distribution or toner with a small particle size in order to improve the quality of copied images. It is difficult to produce a toner with a sharp particle size distribution or a toner with a small particle size, resulting in a considerable increase in cost. In addition, when toner with a sharp distribution or toner with a small particle size is produced by a pulverization method, the particle size distribution of the pulverized product tends to be broad and a large amount of unnecessary ultrafine powder is generated, and the generated ultrafine powder is classified. It is extremely difficult to remove by

Furthermore, in order to be effectively pulverized in this pulverization method, the toner material must have appropriate brittleness, so the selection of raw materials is limited to those having such brittleness. Additionally, when softer materials are used to improve toner fixability, the heat and pressure generated during pulverization can easily cause fusion in the equipment used in various processes. In such a case, it becomes impossible to operate the toner manufacturing apparatus continuously for a long time.

In order to overcome these problems, we developed a method that does not involve dry grinding.
One method for producing toner using a suspension polymerization method has been proposed. This method is an excellent method that eliminates the above-mentioned disadvantages by omitting the melt-kneading process and the crushing process. However, in dry toner production using the conventional suspension polymerization method, the following problems New problems are emerging.

That is, firstly, in toner production using a normal suspension polymerization method, a granulation process is performed in which a liquid monomer composition containing a polymerizable monomer and a colorant is granulated in a liquid dispersion medium. However, there is a problem in that it is very difficult to efficiently control the particle size to a desired value. Secondly, in the current suspension polymerization method, the particle size distribution of the produced polymer particles is wide, and polymer particles with large particle sizes are produced, so it is difficult to maintain an appropriate weight proportion of particles in the particle size range. There is a problem that productivity is not good. In the above-mentioned pulverization method, the particles removed in the classification operation to obtain an appropriate particle size range are remixed with the raw materials and then reused through a kneading process, whereas in this suspension polymerization method, Currently, it is difficult to reuse the resulting polymer particles with poor particle size.

In the suspension polymerization method, in order to solve the problem of particle size distribution as described above, it is necessary to manufacture particles of a monomer composition with a particle size that can finally produce a toner with a desired particle size distribution. It is necessary to produce it stably and with good yield in the granulation process, but in this respect, there are still many problems that need to be solved with conventional suspension polymerization methods.

One of the most important of these issues is the issue of dispersion stabilizers to obtain proper particle size distribution. In other words, in the suspension polymerization method, the main steps are carried out in a liquid medium (
(Usually water is used as a medium), but in the granulation process,
Dispersion stabilizers are used to form and stabilize monomer composition particles. As such a dispersion stabilizer,
Normally, poorly water-soluble inorganic fine powders such as BaSO4, CaSO4, CaCO3, silicic acid (silica), water-soluble polymers such as polyvinyl alcohol and gelatin, or water-soluble surfactants are used alone or in combination. .

Due to their role, these dispersion stabilizers have strong wood-philic properties, and if they remain in the produced toner, the developing ability and transfer efficiency will decrease mainly due to a decrease in the chargeability of the toner. In particular, under conditions of high humidity, image quality such as a decrease in copy density, a decrease in resolution, and blurring and flickering occur. Therefore, from this point of view, it is required to reduce the amount of dispersion stabilizer used, but on the other hand, by using a small amount of dispersion stabilizer, it is possible to reduce the particle size of the monomer composition and improve the particle size distribution. We have to solve the problem of sharpening.

In order to solve this problem, we have improved the material of the dispersion stabilizer itself,
Efforts have been made to reduce the amount used, but in conventional dispersion methods, simply reducing the amount of dispersion stabilizer results in the monomer composition particles having a coarse particle size and a wide particle size distribution, resulting in monomer composition particles being formed in the subsequent polymerization process. Secondary aggregation of polymer composition particles frequently occurs, making it difficult to obtain a polymer with an appropriate particle size. especially,
When trying to obtain a toner with a sharp particle size distribution or a toner with a small particle size, this secondary aggregation becomes an extremely serious problem.

An object of the present invention is to provide a method for efficiently producing a toner with an extremely narrow particle size distribution and an easy control of the average particle size in the production of a toner for electrostatic image development using a suspension polymerization method. It is about providing.

Another object of the present invention is to provide a method for efficiently producing dry toner with small particle size.

Still another object of the present invention is to provide a method for producing a toner having a homogeneous and sharp particle size distribution while reducing the amount of dispersion stabilizer used in toner production using a suspension polymerization method. .

Still another object of the present invention is to provide a method for producing a toner having good powder characteristics and good development, transfer, fixing, and cleaning properties.

Still another object of the present invention is to provide a method for producing toner at low cost and with good productivity.

1101 As a result of our extensive research in order to solve the various problems mentioned above, the present inventors have discovered that monomers can be formed under the interaction of shear forces based on two or more high-shear force stirring devices in the coexistence of a dispersion stabilizer. Granulating the composition not only enables granulation with a uniform and sharp particle size distribution (even when using a smaller amount of dispersion stabilizer), but also allows for It has been found that the uniform dispersibility of colorants can be significantly improved.

The toner manufacturing method of the present invention is based on such knowledge, and more specifically, a monomer composition containing at least a polymerizable monomer and a colorant is mixed with a dispersion stabilizer in a granulation container. When dispersing and granulating it in a liquid dispersion medium containing and commercially incompatible with the polymerizable monomer; two or more high shear force stirring devices arranged in the granulation container; It is characterized in that it is used for granulation.

The reason why the above-mentioned effects can be obtained in the present invention is as follows.
Although it is not necessarily clear, it is estimated as follows.

In the granulation step of this production method, the monomer composition is granulated by shearing force, impact, and turbulence based on the action of two or more high-shear force stirring devices in the presence of a dispersion stabilizer. However, at this time, the synergistic effect of the impact between the dispersion liquids flowing out from each stirring device and the complicated turbulence generated around each stirring device significantly improves the granulation efficiency.

Furthermore, in this granulation process, dispersion in the liquid dispersion medium,
The suspended and micronized monomer composition particles are subjected to a predetermined stabilizing action of a dispersion stabilizer, and the coarse composition particles having a large particle size of a certain degree or more are subjected to the above-mentioned shear force, impact,
Although the particles of the composition having a predetermined particle size are further atomized by the action of turbulence, it is difficult to further atomize them due to the relative increase in the protective effect of the dispersion stabilizer at the particle size. The number of composition particles having .

Therefore, according to the production method of the present invention, by combining the improvement in granulation efficiency and the increase in the protective effect of the dispersion stabilizer, an extremely sharp particle size distribution of monomer composition particles can be achieved in a short period of time. It is estimated that the amount can be obtained in time.

Furthermore, in the present invention, the dispersibility of the colorant in the monomer composition particles is significantly improved, and this is presumed to be due to the following reasons.

That is, in monomer composition particles containing a pigment as a colorant (especially magnetic particles with high specific gravity), agglomeration and uneven distribution of the colorant tend to occur. Particles are processed as in conventional granulation process (JIL
It is presumed that when a strong and non-uniform shearing force (from the stirring device) is applied, the uneven distribution of the colorant becomes more pronounced among the finely divided monomer particles.

On the other hand, in the granulation process of the present invention, two or more high shear force stirring devices apply a more averaged shear force to the monomer composition particles, so that the monomer composition particles are finely divided by this shear force. The colorant is less likely to be unevenly distributed among the particles, and since the time interval until the monomer composition particles that have been subdivided are subdivided again is short, the colorant in the particles during this time is It is presumed that by combining these two effects that agglomeration and uneven distribution are less likely to occur, the present invention achieves improved uniform dispersibility of the colorant in the monomer composition particles.

In particular, when the monomer composition contains a polymerization initiator,
The above-mentioned difference in uniform dispersibility of colorants becomes more significant.

In such a case, as the viscosity of the monomer composition particles increases even during the granulation process, the colorant, which had previously been moving around relatively freely and repeating aggregation and dispersion, gradually stops moving. This is presumed to be because it becomes difficult for the colorant, once aggregated and unevenly distributed, to become dispersed again.

The present invention will be explained in more detail below. In the following description, "1 part" and "1%" expressing quantitative ratios are based on weight unless otherwise specified.

In the production method of the present invention, the monomer composition containing a polymerizable monomer of styrene, a coloring agent such as carbon black, and a polymerization initiator (if necessary) has a stable dispersion. In the presence of the agent, the particles are dispersed and suspended in a liquid dispersion medium by shearing force, impact, and turbulence applied from two or more high-shear force stirring devices, and are preferably granulated as particles with an average particle size of 15 μm or less. Ru.

In the present invention, as such a high shear force stirring device, a turbine type stirrer that applies high shear force to the dispersion liquid using a high speed rotating turbine and a stator, as shown in a schematic side sectional view in FIG. A high-speed dispersion machine (la in FIG. 4(C) described later) that applies high shear force to the dispersion liquid using a stirring blade that rotates at high speed is preferably used.

Referring to FIG. 1, such a turbine type agitator 1 is as follows:
A turbine 2 that rotates at high speed, a stator 3 that applies shear force to the dispersion liquid between this turbine, and a dispersion liquid outlet 4
It is composed of a turbine bearing 4 provided with a dispersion liquid inlet 5a, and a bottom plate 5 provided with a dispersion liquid inlet 5a.

In such a turbine type stirrer 1, a dispersion liquid 6 consisting of a monomer composition and a liquid dispersion medium enters the stirrer 1 through the injection port 5a, and is generated between the turbine 2 and the stator 3 which rotate at high speed. Strong shear force, #! I. After being stirred by the turbulent flow and forming micron-order monomer composition particles, they flow out from the dispersion outlet 4a.

In the agitator 1 having the above configuration, the high viscosity turbine 2a1 has a shape as shown in a schematic perspective view in FIG. 2(a) depending on the viscosity of the monomer composition (in this case, there is no bottom plate).
Alternatively, a low-viscosity turbine 2b having a shape as shown in a schematic perspective view in FIG. 2(b) is preferably used. In addition, the third
Figures (a,) and 3 (b) show these high viscosity turbine 2a and low viscosity turbine 2b, respectively.
A schematic side sectional view showing the state arranged inside the stator 3 (
However, the turbines 2a and 2b are shown in a schematic side view.
).

Examples of such a turbine type agitator 1 include T, Homo mixer, "r", manufactured by Tokushu Kika Kogyo Co., Ltd.
It is preferable to use a stirrer such as Unimixer or TK Combimix.

On the other hand, as described above, in the present invention, a high-speed dispersion machine having stirring blades rotating at high speed is also preferably used as the high-shear force stirring device. This high-speed disperser forms particles on the micron order by stirring a dispersion liquid at high speed using shear force, impact, and turbulence caused by stirring blades. As this high-speed disperser, it is preferable to use, for example, TK Momodisbar manufactured by Tokushu Kika Kogyo Co., Ltd.

In addition, in the present invention, a stirring device that generates a large flow in the liquid, such as an anchor type mixer, is
Although the effect on particle formation is small, it helps to adjust the flow of the liquid in the container, and the synergistic effect with the two high shear force stirring devices allows for more preferable particle formation.

A preferred combination of stirrers used in the present invention is, for example, as shown in a schematic side cross-sectional view in FIG. be. In this case, Fig. 4(b)
It is more preferable to combine an agitator 7 such as an anchor type mixer as shown in FIG.

Another preferred combination, as shown in a schematic perspective view in FIG. 4(C), is the combined use of a turbine type stirrer 1 such as a TK homomixer and a high-speed disperser 1a such as a TK homodisper. In this case, it is more preferable to further combine a stirrer 7 such as an anchor type mixer.

In the present invention, two or more of the above-mentioned high shear force stirring devices may be placed in the same granulation container, and the manner of arrangement (position, interval, etc.) is not particularly limited; From the viewpoint of averaging the applied shearing force, the granulation container 6
It is preferable that the two or more stirring devices are arranged symmetrically with respect to a perpendicular line passing through the center of the bottom surface of the stirring device.

Further, as for the shape of the granulation container, a container with a round bottom is preferable, and this is thought to be because it does not have corners or dead spaces that would impede the flow of the liquid.

Furthermore, it is preferable that the stirring parts of the stirring device be installed so that both parts are at the same height.

In such a granulation process, if a polymerization initiator is contained in the monomer composition, such a monomer composition will contain monomers as the polymerization progresses even during granulation. The viscosity of the dispersion liquid increases as it gradually changes from a liquid to a polymer. In this case, as the viscosity increases, the granulation properties of the agitator may gradually decrease, making it difficult to form fine particles.

In order to solve this problem, the granulation temperature is lowered (
! It is also possible to perform granulation by slowing down the progress of coalescence, but this would change the molecular weight distribution necessary for the toner properties, which is undesirable, and the solubility of added materials (for example, substances such as wax) may change. From this point of view, it may be difficult to lower the granulation temperature.

On the other hand, it is also conceivable to granulate at a temperature at which polymerization does not substantially proceed (very low temperature) and then to raise the temperature after granulation to carry out polymerization, but granulation may still be difficult for the above-mentioned reasons.

However, according to the present invention, by simultaneously applying shear force from two or more stirrers, the efficiency of granulation is significantly increased, and even when a polymerization initiator is included in the monomer composition, the temperature Pelletization can be carried out efficiently in a short period of time without being substantially influenced by the above, and preferred micronization can be achieved.

Furthermore, as mentioned above, in the present invention, a remarkable improvement in colorant dispersibility in the produced polymerized toner is observed, so that toner particles containing a small amount of colorant or toner particles containing substantially no colorant can be obtained. The generation of particles (particularly common in fine powder toner) is extremely small.

Such improvement in colorant dispersibility is particularly remarkable when a polymerization initiator is included in the monomer composition or when the colorant is magnetic particles with high specific gravity.

This is because (as mentioned above) in the present invention, the non-uniform force that occurs in forced granulation due to the action of strong shearing force does not work, so particles with a small amount of colorant are extremely rarely generated. It will be done.

The dispersibility of the colorant is one of the very important characteristics of a toner in terms of forming a clear image or maintaining the quality of an initial image during continuous use.

In the granulation process of the present invention, when a solid fine powder dispersion stabilizer such as silica is used as a dispersion stabilizer, the coarse monomer composition particles are finely divided and at the same time form agglomerates. The aggregates of the fine powder dispersion stabilizer that were not working effectively during the dispersion are further dispersed and become closer to particles that are more effectively distributed, so that the dispersion stabilizing ability of the dispersion stabilizer as a whole is improved. As a result, the finely divided monomer composition particles are protected by the fine powder dispersion stabilizer having improved dispersion stabilizing ability. Therefore, the possibility of further fragmentation of the monomer composition particles is extremely low compared to conventional granulation methods.

Furthermore, when the dispersion stabilizer is a solid fine powder dispersion stabilizer such as fine silica powder, it is also preferable to add a step of dispersing the fine powder dispersion stabilizer itself before this granulation step.

Here, the dispersion process of the fine powder dispersion stabilizer refers to a process of reducing aggregates of the dispersion stabilizer in the dispersion medium and forming a fine powder dispersion stabilizer that is better dispersed. By providing the dispersion step, the dispersion stabilizing ability of the dispersion stabilizer as a whole is improved, and the finely divided monomer composition particles are protected by the fine powder dispersion stabilizer with improved dispersion stabilizing ability. This is preferable because

Dispersion equipment used in the dispersion stabilizer dispersion process includes:
Apparatus such as a high shear force mixer such as a TK homomixer, a piston type high pressure homogenizer, etc. are preferably used.

The liquid temperature during the granulation process used in the present invention is such that the monomer composition has a viscosity of 1 to 1 million cps, preferably 100,000 to 100,000 cps.
When the temperature is adjusted to s, the particle size of the monomer composition particles can be set to 1 to 20 μm, and finally a developing toner having a volume average particle size of 1 to 20 μm can be produced. As the liquid dispersion medium, usually water or an aqueous medium containing water as a main component is preferably used.
The temperature is preferably adjusted to 40 to 70°C.

In the above dispersion, it is preferable that the liquid dispersion medium is present in an amount of 200 to 1000 parts per 100 parts of the monomer composition, and the dispersion stabilizer is preferably present in an amount of 1 to 10 parts per 100 parts of the liquid dispersion medium. Furthermore, it is preferable to use 3 to 8 parts.

In the granulation process of the present invention, by using two or more shear force stirring devices as described above, monomer composition particles having the same average particle size having a weight average particle size of about 1 to 20 μm are mixed using the conventional method. When monomer composition particles are produced using a single stirring and mixing device commonly used in
It is possible to perform granulation with an amount of dispersion stabilizer of about 0%. Furthermore, as described above, in the present invention, the time required for the granulation process can be made significantly shorter than in the past.

Before subjecting the monomer composition particles formed by the detailed granulation process detailed above to the next polymerization process, the monomer composition particles may be subjected to classification treatment using a wet classifier, etc., as necessary. It's okay.

At this time, particles with the desired particle size generated during granulation are separated from particles with a particle size outside the specified size using a classifier, and then the particles are combined,
The mixture is led to a polymerization step using a gentle stirring device set to conditions that prevent sedimentation, and subjected to a polymerization reaction.

On the other hand, the non-standard coarse particles separated by the classifier are returned to the granulation process, and then subjected to the granulation process to obtain particles of the desired particle size, and then sequentially taken out as particles of the desired particle size in the same manner as above. , is preferably similarly subjected to a polymerization step.

As a result, coarse particles can be atomized as desired without being affected by the miniaturization of monomer composition particles having a desired particle size, making it possible to improve the yield in the granulation process.

When performing such a classification process, it is preferable to use a so-called wet classifier that utilizes the difference in sedimentation speed of particles in a liquid.

Wet classifiers are classified into settling tank type, mechanical classifier type, hydraulic classifier type, hydrocyclone type, centrifugal classifier type, inertial force classifier type, etc. In the present invention, hydraulic classifier type, hydro classifier type, etc. A cyclone type, a centrifugal classifier type, and an inertial force classifier type are preferably used, and among them, a hydrocyclone type, a centrifugal classifier type, and an inertial force classifier type are particularly preferably used.

Next, the materials constituting the monomer composition will be explained.

The polymerizable monomer used in the present invention is a monomer having a CH2-C group, and specifically, the following monomers have a CH2-C group.
can be given.

That is, styrene, 0-methylstyrene, m-methylstyrene, p-methylstyrene, p-methoxystyrene, p-phenylstyrene, p-chlorostyrene, 3.4
-dichlorostyrene, p-ethylstyrene, 2,4-dimethylstyrene, p-n-butylstyrene, p-te
rt-butylstyrene, P-n-hexylstyrene,
p-n-octylstyrene, p-n-nonylstyrene,
p-n-decylstyrene, p-n-dodecylstyrene,
Styrene and its derivatives such as; ethylenically unsaturated monoolefins such as ethylene, propylene, butylene, and isobutylene; vinyl halides such as vinyl chloride, vinylidene chloride, vinyl bromide, and vinyl fluoride; vinyl acetate, vinyl propionate, Vinyl esters such as vinyl benzoate: methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, isobutyl methacrylate 1. ', α-methylene aliphatic monocarboxylic acid esters such as n-octyl taacrylate, dodecyl methacrylate, 2-ethylhexyl methacrylate, stearyl methacrylate, phenyl methacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate; Methyl acrylate, ethyl acrylate, n-butyl acrylate, isobutyl acrylate,
Acrylic acid esters such as propyl acrylate, 1lln-octyl acrylate, dodecyl acrylate, 2-ethylhexyl acrylate, stearyl acrylate, 2-chloroethyl acrylate, phenyl acrylate; maleic acid, maleic acid hafester; vinyl methyl ether, Vinyl ethers such as vinyl ethyl ether and vinyl isobutyl ether; Vinyl ketones such as vinyl methyl ketone, vinyl hexyl ketone, and methyl isopropenyl ketone; N-vinyl compounds; vinylnaphthalenes; acrylic acid or methacrylic acid derivatives such as acrylonitrile, methacrylonitrile, acrylamide, etc. can be used alone or in combination of two or more.

Among the above monomers, it is preferable to use styrene or a styrene conductor alone or in combination with other monomers as a polymerizable monomer, from the viewpoint of improving toner development characteristics and durability.

The monomer composition contains waxes such as paraffin wax, and releasable materials such as low molecular weight polyolefins such as low molecular weight polyethylene and low molecular weight polypropylene, in order to improve fixing properties and anti-offset properties in hot pressure roller fixing. A low softening point compound (preferably a melting point of 60~
130°C), in this case,
The amount of the low softening point compound added is 1 to 300 parts, more preferably 4 to 100 parts, per 100 parts of the polymerizable monomer.

Examples of low softening point compounds include paraffin, wax, low molecular weight polyolefin, modified wax having an aromatic group,
Hydrocarbon compounds having an alicyclic group, natural waxes, long-chain carboxylic acids having a long-chain hydrocarbon chain having 12 or more carbon atoms (CH, (CH2 arrow 11 or aliphatic carbon chain having (CHz)u or more)), and esters thereof. For example, different low softening point compounds may be mixed and used.

Examples of such low softening point compounds include paraffin wax (manufactured by Nippon Oil), paraffin wax (manufactured by Nippon Seiro), microwax (manufactured by Nippon Oil), microcrystalline wax (manufactured by Nippon Seiro), and hard crystalline wax. Paraffin wax (manufactured by Nippon Seiro) PE-130 (manufactured by Hoechst):
Mitsui Heiwax 5top, Mitsui Hiwax 220P
, Mitsui Hiwax 660P, Mitsui Yaiwax 210
P, Mitsui Wax 320P, Mitsui Yawax 41
0P, Mitsui Heiwax 420P, Hiraytsu T-10
0X, A-ray'/T-200X, A-lets T-30
0X, Vetrogin 80, Vetrogin 100, Vetrogin 120, Tac Ace A-100, Tac Ace F-1
00, Tac Ace B-60, modified wax JC-11
41. Modified wax JC-2130, modified wax JC
-4020, modified wax JC-1142, modified wax JC-5020 (manufactured by Mitsui Petrochemicals); beeswax, carnauba wax, montane wax, and the like.

In the monomer composition, in order to produce a crosslinked polymer,
Suspension polymerization may be carried out in the presence of the following cross-linking agents. In particular, when no polymer, copolymer or cyclized rubber is added to the monomer composition, the following cross-linking agents may be added. is preferred.

Examples of the crosslinking agent include divinylbenzene, divinylnaphthalene, polyethylene glycol dimethacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, 1.3-butylene glycol dimethacrylate, 1.6-hexane gelicold dimethacrylate, and neopentyl glycol dimethacrylate. metharylate, diethylene glycol diacrylate, polypropylene glycol dimethacrylate, 2.2'-bis(4-methacryloxydiethoxyphenyl)propane, 2.2'
-bis(4-acryloxyjetoxyphenyl)propane, trimethylolpropane trimethacrylate, trimethylolpropane triacrylate, tetramethylolmethanetetraacrylate, dibromneopentylglycol dimethacrylate, diallyl phthalate, etc.
General crosslinking agents can be used as appropriate.

If the amount of these crosslinking agents used is too large, the toner will be difficult to melt with heat, resulting in poor heat fixing properties or heat pressure fixing properties. Also, if the amount of crosslinking agent used is too small, properties such as blocking resistance and durability necessary for toner will deteriorate, and during hot roll fixing, some of the toner will not completely adhere to the paper and will adhere to the roller surface. , it becomes difficult to prevent the offset phenomenon of transfer to the next paper.Therefore, the amount of these crosslinking agents to be used is from o,oot to 15 parts (more preferably from 0°1 to 15 parts per 100 parts of the polymerizable monomer). ~10 copies)
Good to use.

As the coloring agent contained in the monomer composition, pigments such as conventionally known dyes, carbon black, and grafted carbon black obtained by coating the surface of carbon black with a resin can be used. The agent is used in an amount of 0.1 to 30 parts per 100 parts of the polymerizable monomer.

A charge control agent and a fluidity modifier may be added to the toner as necessary.The charge control agent and fluidity modifier may be mixed (externally added) with the toner particles and used. It's okay.

Examples of charge control agents include metal complexes of organic compounds having carboxyl groups or nitrogen-containing groups, metal-containing dyes, and nigrosine. Examples of fluidity improving agents or cleaning aids for the surface of the latent image carrier (photoreceptor) include colloidal silica and fatty acid metal salts. In addition, fillers such as calcium carbonate and finely divided silica may be added to the toner in an amount of 0.5 to 20% by weight for the purpose of increasing the amount. In order to improve the flowability, a flowability improver such as Teflon fine powder or zinc stearate powder may be added to improve the flowability.

To produce a magnetic polymerized toner, magnetic particles may be added to the monomer composition, and in this case, the magnetic particles also serve as (all or part of) a colorant.

The magnetic particles that can be used in the production method of the present invention include particles that are magnetized by being placed in a magnetic field, such as powders of ferromagnetic metals such as iron, cobalt, and nickel, or powders of ferromagnetic metals such as magnetite, hematite, and ferrite. Examples include powders of alloys and compounds. As the magnetic particles, magnetic fine particles having a particle size of 0.05 to 5 μl, preferably 0.1 to 1 μl are used, but when producing a small particle size toner, a particle size of 0.8 μl or less is used. Preference is given to using magnetic particles.

The magnetic particles are contained in 10 to 6 parts per 100 parts of the monomer composition.
It is preferably contained in an amount of 0 parts, more preferably 20 to 50 parts.

Furthermore, these magnetic fine particles may be treated with a surface treatment agent such as a silane coupling agent or a titanium coupling agent, or an appropriate reactive resin. In this case, the surface area of the magnetic fine particles or the hydroxyl groups present on the surface may be Although it depends on the density, sufficient dispersibility in the polymerizable monomer can usually be obtained with a treatment amount of 5 parts or less (preferably 0.1 to 3 parts) of the surface treatment agent, etc. per 100 parts of the magnetic fine particles. In addition, magnetic particles rendered lipophilic by the above treatment and untreated hydrophilic magnetic particles may be used in combination.

Next, the polymerization initiator used for polymerizing the monomer composition made of the above-mentioned materials will be described.

In the present invention, the polymerization initiator may be added to the dispersion containing the monomer composition after granulation, but from the point of view of uniformly applying the polymerization initiator to each monomer composition particle, It is preferable to include it in the monomer composition before granulation.

According to the findings of the present inventors, when a water-soluble polymerization initiator is used, the moisture resistance of the resulting polymerized toner decreases, and the development characteristics and blocking resistance at high temperatures deteriorate. In order to produce a polymerized toner with excellent properties, it is preferable to use a substantially water-insoluble polymerization initiator.

Here, in the present invention, a substantially water-insoluble polymerization initiator has a solubility of 1 g or less per 100 g of water at room temperature, and preferably has a solubility of 0 g or less per 100 g of water.
．． 5g or less, particularly preferably 0.2 per 100g of water
It has a low solubility of less than g.

When the polymerization initiator has a solubility of more than 1 g per 100 g of water, it is not preferable because the decomposition products of the polymerization initiator remaining on the surface of the polymerized toner particles after completion of polymerization deteriorate the moisture resistance of the polymerized toner.

Further, the polymerization initiator used in the present invention is preferably soluble in the polymerizable monomer, and the amount ranges from the amount usually used (for example, 1 to 10 parts of the polymerization initiator per 100 parts of the polymerizable monomer). ) preferably has solubility characteristics that allow it to dissolve well in the polymerizable monomer.

As such a polymerization initiator, 2,21-azobis-
(2,4-dimethylvaleronitrile), 2,2'-azobisisobutyronitrile, 1°1'-azobis(cyclohexane-1-carbonitrile), 2,2'-azobis-4-methoxy-2, Azo or diazo polymerization initiators such as 4-dimethylvaleronitrile and other azobisisobutyronitrile (AIBN); benzoyl peroxide, methyl ethyl ketone peroxide, isopropyl peroxy carbonate, cumene hydroperoxide, 2.4- Examples include peroxide-based polymerization initiators such as dichloryl benzoyl peroxide and lauroyl peroxide.

In the production method of the present invention, the polymerization initiator has a polymerization temperature (
It is preferable to have a melting point equal to or lower than 50°C (normally 50°C or higher).Also, for the purpose of adjusting the molecular weight and molecular weight distribution of the polymer, or for the purpose of adjusting the reaction time, two or more types of polymerization It is also preferred to use a mixture of initiators.

The amount of the polymerization initiator used is usually 0.1 to 20 parts, preferably 1 to 10 parts per 100 parts of the polymerizable monomer. If the amount of the polymerization initiator is less than 0.1 part, each monomer It is difficult to uniformly disperse or apply a sufficient amount of the polymerization initiator to the composition particles; on the other hand, if the amount of the polymerization initiator exceeds 20 parts,
As the molecular weight of the polymerization product decreases, the tendency for the polymerization reaction to occur non-uniformly increases.

In the present invention, the suspension polymerization reaction is usually carried out at a polymerization temperature of 50
The upper temperature limit is set in consideration of the decomposition rate of the polymerization initiator. If the set polymerization temperature is too high, the polymerization initiator will be rapidly decomposed, which is not preferable.

After confirming that the monomer composition particles formed by the granulation process have a predetermined particle size, adjust the liquid temperature of the dispersion medium such as an aqueous medium containing the particles (for example, to 55 to 70 ° C.) to allow the polymerization reaction to proceed.

Furthermore, when an additive consisting of a polar polymer, a polar copolymer, or a cyclized rubber having a polar group that dissolves in the polymerizable monomer is added to the monomer composition, the polymerizable monomer is polymerized. , a polymerized toner having favorable properties can be obtained.

The polar polymer, polar copolymer or cyclized rubber may be used in an amount of 0.5 to 50 parts, more preferably 1 to 50 parts, based on 100 parts of the polymerizable monomer.
It is best to add 40 parts of the polar polymer, etc. If the amount of the polar polymer, etc. is less than 0.5 part, it will be difficult to form a sufficient quasi-capsule structure with the polymerizable monomer as described below. If it exceeds the amount, the amount of polymerizable monomer becomes insufficient, and the properties as a polymerized toner tend to deteriorate.

A polymerizable monomer composition to which a polar polymer, a polar copolymer, or a cyclized rubber is added is added to the aqueous phase of an aqueous medium in which the polar polymer, etc. and an oppositely charged fine powder dispersion stabilizer are dispersed. Preferably, the cationic or anionic polymer, cationic or anionic copolymer or anionic cyclized rubber contained in the polymerizable monomer composition is suspended and polymerized in an aqueous medium. The oppositely charged anionic or cationic fine powder dispersion stabilizer dispersed in the particles attracts each other electrostatically on the surface of the toner particles, and the fine powder dispersion stabilizer covers the particle surface, which causes the particles to coalesce. It prevents and stabilizes. In addition, since the added polar polymer, polar copolymer, or cyclized rubber gathers on the surface layer of the particles that will become the toner, the polar polymer etc. forms a kind of shell-like form.
The obtained particles have a pseudo-capsule structure. The relatively high molecular weight polar polymer, polar copolymer, or cyclized rubber gathered on the surface layer of the particles gives the toner particles excellent properties such as blocking resistance, developability, charge controllability, and abrasion resistance. give protection.

Some of the polar polymers (hereinafter used to include polar copolymers and cyclized rubbers) that can be used in the present invention are illustrated below. Note that polar polymers having a weight average molecular weight of 5.000 to soo, ooo as measured by GPC are preferably used because they dissolve well in the polymerizable monomer and have durability.

(1) Examples of the cationic polymer include polymers of nitrogen-containing monomers such as dimethylaminoethyl methacrylate and diethylaminoethyl acrylate, copolymers of styrene and the nitrogen-containing monomers, or styrene and unsaturated carboxylic acids. There are copolymers of esters and such nitrogen-containing monomers.

(2) Examples of anionic polymers include nitrile monomers such as acrylonitrile, halogen-containing monomers such as vinyl chloride, unsaturated carboxylic acids such as acrylic acid, unsaturated dibasic acids,
There are polymers or copolymers of anhydrides of unsaturated dibasic acids, or copolymers of styrene and these monomers. Polyesters and cyclized rubbers can also be used as anionic polymers.

On the other hand, as the dispersion stabilizer, either a wood-philic organic dispersant or a fine powder dispersion stabilizer can be used, but from the viewpoint of improving the moisture resistance of the obtained toner, a fine powder dispersion stabilizer is preferably used. It will be done.

Examples of hydrophilic organic dispersants include polyvinyl alcohol, gelatin, methyl cellulose, methyl hydroxypropyl cellulose, ethyl cellulose, sodium salt of carboxymethyl cellulose, polyacrylic acid and salts thereof, starch, gum alginate, zein, casein, etc. .

As the fine powder dispersion stabilizer, preferably used is an inorganic fine powder that has the ability to stabilize the dispersion of the monomer composition particles in a liquid medium such as an aqueous medium and is soluble in water. The amount of the dispersant added to the aqueous medium is 0.5 to 0.5 to
It is good to add 50% (preferably 1 to 20%).

As an anionic fine powder dispersion stabilizer, Aerosil #2
00, #300 (manufactured by Nippon Aerosil Co., Ltd.) Nib Seal E-
22OA (made by Nippon Silica), Fine Seal T-32
(manufactured by Tokuyama Soda) and the like are colloidal silicas.

Examples of the cationic fine powder dispersion stabilizer include aluminum oxide, magnesium oxide, and hydrophilic positively charged silica fine powder such as aminoalkyl-modified colloidal silica using a coupling agent.

In the production method of the present invention, although a dispersion stabilizer is necessary, it is not necessarily necessary to use a dispersion stabilizer that has a charge opposite to that of the polar polymer in the liquid medium.

In addition, in combination with the above-mentioned fine powder dispersion stabilizer, a suitable stabilizer such as polyvinyl alcohol, gelatin, methyl cellulose, methyl hydropropyl cellulose,
Ethylcellulose, sodium salt of carboxymethylcellulose, polyacrylic acid and their salts, starch, gum alginate, zein, casein, tricalcium phosphate, talc, barium sulfate, bentonite, aluminum hydroxide, ferric hydroxide, hydroxide Any one of titanium, thorium hydroxide, etc. or a mixture of two or more thereof may be contained in the aqueous medium to the extent that it does not adversely affect the production method of the present invention.

Furthermore, for uniform dispersion of the inorganic dispersion stabilizer, a surfactant may be used within a range that does not adversely affect the production method of the present invention, and this will promote the intended action of the dispersion stabilizer. Specific examples include sodium dodecylbenzenesulfonate, sodium tetradecylsulfate, sodium pentadecylsulfate, sodium octylsulfate, sodium allyl-alkyl-polyethersulfonate, sodium oleate, sodium laurate, and caprin. sodium acid, sodium caprylate,
Sodium caproate, potassium stearate, calcium oleate, 3.3-disulfonodiphenylurea-
4,4-diazo-bis-amino-8-naphthol-6-
Sodium sulfonate, ortho-carboxybenzene
Azo-dimethylaniline, 2,2,5.5-tetramethane, routriphenylmethane-4,4-diazo-bis-
Examples include sodium β-naphthol-disulfonate and others. However, it should be noted that when a hydrophilic organic stabilizer or surfactant is used, the moisture resistance of the polymerized toner tends to decrease.

In order to increase the ionicity of the polar groups of the polar polymer or cyclized rubber in the monomer composition, it is also preferable to add a Brønsted acid such as hydrochloric acid to the aqueous medium. Adding it to an aqueous medium is more preferable in order to enhance the effect of the anionic polymer, anionic copolymer or cyclized rubber and the dispersant (particularly the cationic fine powder dispersant).

After the polymerization reaction is completed, by post-processing in the usual manner,
For example, after washing the produced polymer particles to remove the dispersion stabilizer, they are collected by an appropriate method such as filtration, decanting, centrifugation, etc., and dried to obtain polymerized toner particles. can get.

This polymerized toner can be used, for example, in a two-component development method such as a cascade method, a magnetic brush method, a microtoning method, or a two-component AC bias development method: a conductive-component development method, an insulating-component development method, and a jumping development method. One-component development method using magnetic toner such as powder cloud method and fur brush method; non-magnetic Component development method: Applicable to electric field curtain development method, etc., in which toner is conveyed to a developing section by an electric field curtain method and subjected to development.The toner obtained by the present invention is suitable for use in weight applications where a particularly sharp particle size distribution is required. Average particle size 1y8μ
It can be preferably applied to the developing method (2) using small particle size toner.

As described above, according to the present invention, shear force is applied to the monomer composition in the liquid dispersion medium from two or more high-shear force stirring devices, and the monomer composition is dispersed in a short time. Provided is a method for producing a toner for developing an electrostatic image, in which a toner having excellent properties is obtained by efficiently granulating it into a sharp particle size distribution.

Hereinafter, the present invention will be explained in more detail based on Examples.

Next, 5 parts by weight of amino-modified silica (Aerosil #200 manufactured by Nippon Aerosil Co., Ltd.) was mixed with 5 parts by weight of aminopropyltriethoxysilane. 5 parts, aOO parts of distilled water, and 1/ION
The monomer composition prepared above was added to a stainless steel container (cylindrical shape, bottom diameter 35 cm) with a capacity of 20 IL containing 20 parts of hydrochloric acid, and heated at 60°C using a turbine type stirrer.
The mixture was granulated by stirring at 10°,000 rpm for 10 minutes using a K dry mixer (manufactured by Tokushu Kika Kogyo Co., Ltd.). During this granulation, the TK homomixers (two) were arranged parallel to each other at symmetrical positions with respect to the center of the bottom surface of the stainless steel container with an interval of 9C.

After granulation, the monomer composition was polymerized using a paddle stirring blade at 60° C. for 10 hours.

The polymerized product obtained above was cooled and dehydrated, then washed with a sodium hydroxide solution, dehydrated, and dried to obtain a polymerized toner.

The viscosity of the obtained toner was measured using a Coulter Counter (aperture 100μ), and the volume average particle diameter of the toner was 5.2μm, with 6% by volume of fine powder of 2°52μm or less, and 8°0μm or more. The volume percent of coarse powder was 3%, which was an extremely narrow particle size distribution.

A monomer composition was prepared by mixing at 30°C.

Amino-modified silica (Nippon Aerosil Aerosil #)
Aminopropyltriethoxysilane 5 to 100 parts by weight of 200! ! 6 parts (reacted) and 60 parts of distilled water
Volume 2041 containing 0 parts and 22 parts of 1/ION hydrochloric acid
The monomer composition prepared above was added to a stainless steel container, and the same as in Example 1 was heated at 60°C using a TK homomixer (
10. Using two pieces (made by Tokushu Kika Kogyo). 3 at OOOrpm
After stirring for 0 minutes and granulating, 60
Polymerization was carried out at ℃ for 10 hours.

The resulting polymerized product was cooled, dehydrated, washed with a sodium hydroxide solution, dehydrated, and dried to obtain a polymerized toner.

When the particle size of the obtained toner was measured using a coal tanker (aperture 50 μm), the volume average particle size of the toner was 4.5 μm, and the volume percentage of fine particles of 2.52 μm or less was 3%, and the volume percentage was 8.0 μm or more. The volume percent of coarse powder was 3%, which was an extremely narrow particle size distribution.

A monomer composition (viscosity at 60°C of 300 cps) was prepared by mixing at 30°C.

Next, colloidal silica (Aerosil # manufactured by Nippon Aerosil)
Example 1 except that 5 parts of 200) and 600 parts of water were used.
After granulating in the same manner as above, using a paddle blade stirring blade, 60
Polymerization was carried out at ℃ for 10 hours.

The resulting polymerized product was cooled and dehydrated, then washed with a sodium hydroxide solution, dehydrated, and dried to obtain a polymerized toner.

When the particle size of the obtained toner was measured with a Coulter counter (aperture 100 μm), the volume average particle size was 5.2 μm, and the volume percentage of fine powder of 2.52 μm or less was 6%, The volume percent of coarse powder was 3%, which was an extremely narrow particle size distribution.

BlenAct KR-TTS (manufactured by Ajinomoto Co., Inc.) The above polymerizable monomer mixture was mixed at 30°C using an attritor to form a monomer composition (viscosity at 80°C: 100 cps).
was prepared.

Next, 6 parts of amino-modified silica (100 parts by weight of Aerosil #200 manufactured by Nippon Aerosil were reacted with 5 parts by weight of aminopropyltriethoxysilane) and 60 parts by weight of distilled water.
The monomer composition prepared above was added to a stainless steel container with a capacity of 201 containing 0 parts of 1/ION hydrochloric acid and 20 parts of 1/ION hydrochloric acid.
The mixture was granulated in the same manner as in Example 1 using a powder, and then polymerized.

The obtained polymerizable product was cooled and dehydrated, then washed with a sodium hydroxide solution, dehydrated, and dried to obtain a polymerized toner.

When the particle size of the obtained toner was measured using a Coulter counter (aperture 100 μm), the volume average particle size was 5.5 μm, and the volume percentage of fine powder of 2.52 μm or less was 6%, and the volume percent of fine powder of 8.0 μm or more was 6%. The volume percent of coarse powder was 3%, which was an extremely narrow particle size distribution.

After externally adding 0.4 parts of hydrophobic silica (R-972 manufactured by Aeroseal Co., Ltd.) to 100 parts of the polymerized toner obtained in this way, a commercially available copying machine (manufactured by Canon Corporation, NP-250)
) was used to conduct an image formation test, and the image density was 1.
Good images were obtained.

A toner was obtained by granulation and polymerization in the same manner as in Example 1, except that one TK homomixer was used as the salt agitator.

In this polymerized toner, coarse powder of 16 μm or more was observed, and the toner had a wider particle size distribution than the toner of Example 1.

Granulation and granulation were carried out in the same manner as in Example 4, except that one TK homomixer was used as the stirring means and the granulation time was 60 minutes.
A toner was obtained by polymerization.

When this toner was observed under an optical microscope (400x magnification), many transparent particles (particles containing no colorant) were observed.

After classifying this toner to have an average particle size of 5.5μ■, hydrophobic silica (R-9
72) was added externally to NP-2 in the same manner as in Example 4.
When an image formation test was carried out using No. 50, only rough images with low image areas were obtained.

[Brief explanation of the drawing]

FIG. 1 is a schematic side sectional view showing an embodiment of a high-shear stirring device used in the present invention, and FIGS. 2(a) and 2(b) are schematic perspective views showing an embodiment of a turbine used in the above-mentioned stirring device. FIGS. 3(a) and 3(b) are schematic sectional views showing how the turbine is arranged in the stator, and FIGS. 4(a) and (
b) and (c) are a schematic side sectional view or a schematic perspective view showing the arrangement of two or more stirring devices. 1...High shear force stirring device 2...Turbine 3...Stator 4...★-Bottle bearing 5...Bottom plate 6...Pelletization container 7...Agitator 1 missing]: Figure 4 ( a) Figure 1 (a) (b) Figure 3 High viscosity type Low viscosity type Figure 4 (a) (C) (b)

Claims (1)

[Claims] In a granulation container, a monomer composition containing at least a polymerizable monomer and a colorant is placed in a liquid dispersion medium that contains a dispersion stabilizer and is substantially incompatible with the polymerizable monomer. A method for producing a toner for developing an electrostatic image, characterized in that the granulation is performed using two or more high shear force stirring devices disposed within the granulation container.