JPH0486673A - Composite wax fine particle and production thereof - Google Patents

Abstract

PURPOSE:To obtain the spherical composite wax fine particles with a simple production process at a low production cost by uniformly compounding a specified amt. of one or >= 2 kinds of various kinds of fine particulate org. materials, inorg. materials metals, etc., with one or >= 2 kinds of of various kinds of wax and treating the mixture with a two-fluid spraying nozzle, thereby forming the fine particles. CONSTITUTION:One or >= 2 kinds of various kinds of the wax are melted. The specified amt. of one or >= 2 kinds of of various kinds of the fine particulate org. materials, inorg. materials, metals, etc., are then compounded with the molten wax to form the composite wax. While the composite molten wax obtd. in such a manner is held at the temp. higher than the m.p. of the wax, the wax is sprayed and pulverized by using the two-fluid spraying nozzle, by which the composite wax fine particles are produced. The production process is simplified in this way and since the solvent as a dispersion medium is not required, the production cost is low and the spherical particles are obtainable.

Description

[Detailed Description of the Invention] a. Industrial Application Field The present invention is directed to the application of various organic and inorganic substances in the form of fine particles to wax.
The present invention relates to composite wax particles uniformly blended with metals, etc., and a method for producing the same.

b. Prior Art The pulverization method and the spray dryer method are well known as methods for producing composite wax fine particles, particularly for producing magnetic toners used in electrophotographic developers. As an example of the pulverization method, as shown in Fig. 2, binder resin,
Magnetic powder, colorants, and other additives are melted using hot rolls, etc., sufficiently kneaded, and then finely pulverized using a pulverizer such as a zero-order jet mill that cools and solidifies, followed by classification.

Finally, conductive particles such as carbon black are added,
After thorough mixing, the carbon black is embedded into the surface of the toner to produce a product.

In addition, as a method for efficiently performing the above-mentioned carbon black fixation treatment and, if necessary, spheronization treatment of magnetic toner, an air flow impact type solid particle surface modification/spheronization treatment device ( A method using the Nara Hypuridaising System (Nara Kikai Seisakusho type) is described in JP-A-6283029, JP-A-62-221434, etc.

On the other hand, the spray dryer method, as shown in Figure 3,
Various raw materials such as binder resin, magnetic powder, and additives are mixed and dispersed in a solvent, dissolved or made into a slurry, and then sprayed and dried using a spray nozzle or a spray dryer with a rotating disk to become a fine powder. Let's do it. Next, after classifying and adjusting the particle size, fine powder such as silica is finally added to improve fluidity and produce a product.

Problems to be Solved by the C0 Invention However, the methods for producing magnetic toner using the above-mentioned pulverization method and spray dryer method have the following problems.

That is, the pulverization method requires a complicated manufacturing process.

2) If low melting point resin is crushed using an impact crusher, the resin will adhere to the interior of the machine, and if crushed using a jet mill, the nozzle will become clogged, so use low melting point #A fat as binder resin. difficult to use. 3) It is not possible to obtain spherical toner as in the spray dryer method. There are other problems.

On the other hand, the spray dryer method uses a resin with a high melt viscosity, such as styrene or polyester, as l) the binder resin, so it cannot be sprayed unless it is dispersed in a solvent. 2) Manufacturing costs are high due to the use of solvents. 3) Although it is possible to obtain toner with a nearly spherical shape, there are dents (
particles with traces of evaporated solvent). There are other problems.

In view of the above-mentioned problems, an object of the present invention is to provide spherical composite wax fine particles with a simple manufacturing process and low manufacturing cost, and a method for manufacturing the composite wax fine particles.

d. Means for Solving the Problems In accordance with the above object, the present invention provides a uniform amount of one or more types of fine particulate organic substances, inorganic substances, metals, etc. to one or more types of various waxes. The above problem was solved by forming composite wax fine particles that were dispersed and blended into spherical particles and processed with a two-fluid spray nozzle.

Furthermore, the present invention melts one or more types of various waxes, and blends a certain amount of one or more types of fine particulate organic substances, inorganic substances, metals, etc. into the melted wax to form a composite. The composite molten wax is pressurized while being maintained at a temperature higher than the melting point of the wax, and separately, compressed air maintained at a temperature higher than the melting point of the wax is sprayed together with the composite molten wax using a two-fluid spray nozzle. However, the above problem was solved by making the particles atomized.

Hereinafter, a method for manufacturing a magnetic toner used in an electrophotographic developer according to the present invention will be described based on the block diagram of FIG.
The present invention will be described in detail, but the present invention is not limited thereto.

First, heat one or more types of wax.
Melt the molten wax to a temperature of 10 to 5% below the melting point of the wax.
Fine particles of magnetic powder are added to the molten wax at a predetermined mixing ratio while maintaining the temperature at a predetermined temperature within a range of 0°C higher.
Add additives such as dyes, pigments, and conductive materials, and stir well until uniformly dispersed. The composite molten wax thus prepared is stored in a pressurizable container, and the pressurizable container is applied to a predetermined pressure while being maintained at a predetermined temperature within a range of 10 to 50°C higher than the melting point of the wax. Press down
Ku .

Here, the temperature was set 10°C higher than the melting point of the wax because the composite molten wax is cooled by heat radiation during the time it passes through the piping and is sprayed from the tip of the two-fluid spray nozzle, and is the lower limit temperature so that it does not solidify. The reason why the temperature is set to be 50° C. higher than the melting point of the wax is that this temperature is the upper limit temperature for preventing quality deterioration of the wax. However, depending on the type of wax, the temperature is not necessarily limited to this range, and the temperature may be set within a range that does not cause solidification and quality deterioration as described above.

On the other hand, compressed air is supplied to the two-fluid spray nozzle at a constant set pressure while being heated by an air heating means, and while spraying from the tip of the two-fluid spray nozzle, the air temperature immediately after being sprayed from the tip of the nozzle reaches a predetermined temperature (wax Melting point +10~50
Wait for it to rise to C).

When the compressed air reaches a predetermined temperature and stabilizes, the composite molten wax is supplied to the two-fluid spray nozzle. The composite molten wax is vigorously mixed with compressed air within the nozzle, and is atomized and sprayed from the tip of the nozzle.

The composite wax fine particles treated in this way (hereinafter referred to as magnetic toner) are collected in a spraying chamber, or a collecting device such as a cyclone or a bag collector is connected to the sprayed material, and the magnetic toner is collected using a suction blower or the like. If the toner is being transported to the collecting device, it is separated, collected, and recovered there.

l. If necessary, that is, when a magnetic toner with a narrow particle size distribution is required, a classifier may be used to classify and remove the coarse powder region and/or the fine powder region to produce a product.

Further, by appropriately changing the compressed air pressure and the pressure applied to the molten wax, the amount and particle diameter of the obtained fine particles can be appropriately controlled.

If the magnetic toners have strong adhesion and cohesiveness, ultrafine particles such as anhydrous silica are added to improve the adhesion and cohesion, resulting in a product with good fluidity.

Alternatively, a group of magnetic toner particles in the spray that is atomized and dispersed using a two-fluid spray nozzle,
There is also a method of spraying ultrafine particles such as anhydrous silica and adhering the ultrafine particles to the surface of each magnetic toner to improve the adhesion and cohesiveness of the magnetic toners, thereby producing a product with good fluidity.

The waxes used in the magnetic toner include plant-based natural waxes such as candelilla wax and carnauba wax, animal-based natural waxes such as spermaceti wax and beeswax, mineral-based natural waxes such as montan wax and ceresin, and paraffin wax.・Petroleum-based natural wax such as microcrystalline wax, polyethylene wax, fatty acid amide,
There are synthetic waxes such as N-1 fatty acid amides. Also,
Two or more types of waxes may be mixed at any mixing ratio, as long as they are compatible when melted and mixed. However, although waxes themselves have a low melt viscosity, when various organic substances, inorganic substances, metals, etc. in the form of fine particles are blended, the melt viscosity of this composite molten wax increases markedly. In the case of the method for producing composite wax fine particles of the present invention, it is desirable to suppress the viscosity of the composite molten wax to 2000 cP or less. , or you need to choose an appropriate one from among waxes.

Magnetic powder used in magnetic toner includes fine particles of ferromagnetic metals such as iron, zinc, cobalt, nickel, and manganese;
Alternatively, fine particles of alloys or compounds such as ferrite, magnetite, hematite, etc. can be cited.

Example-1 Candelilla wax (melting point 71"C) 50wt
%γ-hematite (dp50=0.2μ class) 45t%
Charge control agent 5wt% Composite molten wax melted and dispersed at the above blending ratio at 95%
The storage container for the composite molten wax was kept at 6k
g/cta-C; while compressed air of 10 kg/ci-G was supplied to the two-fluid spray nozzle while pressurizing to 12 g/cta-C;
While heating and maintaining the temperature at 0°C, it is supplied to a two-fluid spray nozzle and sprayed from the tip of the nozzle to obtain an average particle system (dp50).
A spherical magnetic toner of 13 μm was obtained. The melt viscosity of the composite molten wax having the above blending ratio was 1000 cP.

Example-2 Composite molten wax melted and dispersed at the same blending ratio as in Example-1 above was maintained at 95°C and was mixed at 6.5 kg/c.
d-G pressure to the two-fluid spray nozzle, and the other 10k
Compressed air of g/cf-C was supplied to a two-fluid spray nozzle while being heated and maintained at 120''C, and was sprayed from the tip of the nozzle to obtain a spherical magnetic toner having an average particle diameter of 23 μm.

Example-3 Carnauba wax (melting point 83°C) 50wt%
T-hematite (dp50=0.2μm) 4
5wt% charge control agent 5wt
% The composite molten wax melted and dispersed at the above compounding ratio was maintained at 120°C, and the storage container of the composite molten wax was supplied to a two-fluid spray nozzle while pressurizing 6 kg/d-G, and the other 10 kg /c (-G compressed air at 130°
The toner was supplied to a two-fluid atomizing nozzle while being heated and maintained at a temperature of C, and atomized from the tip of the nozzle to obtain a spherical magnetic toner having an average particle diameter of 14 μm.

The particle size distribution measuring device used in each of the above examples was a laser light diffraction scattering particle size distribution measuring device (SK-PRO70).
00S Seishin Enterprise ■).

e. Effects of the Invention As described above, the present invention provides the following effects.

l) One or more types of wax are melted, and fine particles of various organic substances, inorganic substances,
A composite molten wax made by blending a certain amount of one or more metals, etc., is kept at a temperature higher than the melting point of the wax, and is atomized by atomization using a two-fluid spray nozzle. Since composite wax particles are manufactured, the manufacturing process is simplified.

2) Furthermore, since no solvent is required as a dispersion medium,
The production cost was low and spherical particles could be obtained.

3) Since the two-fluid spray nozzle is used for spraying, it has become possible to atomize composite molten wax having a melt viscosity of up to about 2000 cP.

4) The composite wax particles of the present invention are not limited to magnetic toners for electrophotographic development, but can also be used to prevent shyness of drugs, sustained release of agricultural chemicals, prevent moisture absorption of hygroscopic organic and inorganic substances, and oxidize fine metal powders. It can be used in a wide range of fields such as food, medicine, agricultural chemicals, and metals for prevention purposes.

[Brief explanation of the drawing]

Figure 1 is a block diagram explaining the steps of the method for producing composite wax particles according to the present invention, Figures 2 and 3 are block diagrams explaining the steps of the same conventional method, and Figure 2 is a block diagram explaining the steps of the conventional method. , Figure 3 shows the spray dryer method.

Claims (1)

[Scope of Claims] 1) A certain amount of one or more types of fine particulate organic substances, inorganic substances, metals, etc., are uniformly dispersed and blended into one or more types of various waxes, and are sphericalized. Composite wax particles processed with a two-fluid spray nozzle. 2) Melting one or more types of various waxes,
A composite molten wax, which is obtained by blending a certain amount of one or more of various organic substances, inorganic substances, metals, etc. in the form of fine particles into the molten wax, is pressurized while maintaining the temperature at a temperature higher than the melting point of the wax. Separately, a method for producing composite wax particles, which comprises spraying compressed air maintained at a temperature higher than the melting point of the wax together with the composite molten wax using a two-fluid spray nozzle to atomize the particles. 3) When spraying and atomizing using a two-fluid spray nozzle, a drug for improving fluidity and preventing caking is sprayed on the composite wax fine particles that are in a dispersed state immediately after spraying. 3. The method for producing composite wax fine particles according to claim 2, wherein a drug is attached to the surface of each composite wax fine particle.