JPS6283029A - Method and apparatus for surface modification of solid particle - Google Patents

Abstract

PURPOSE:To efficiently prepare a function composite/hybrid powdery material having uniform and stable physical properties, by modifying the surfaces of solid particles by a method wherein other solid particles are embedded in or fixed to the surfaces of solid particles using an impact type striking means. CONSTITUTION:A powder to be treated, wherein sub-particles are adhered to the surfaces of a definite amount of main particles, for example, by utilizing an electrostatic phenomenon, is charged in a stock material hopper 14 from a weighing feeder 16 within a short time and enters an impact chamber 18 through a chute 15 and the powder particle group is subjected to instantaneous striking action by a large number of impact pins 5 of a rotary disc 4 rotating at a high speed in the impact chamber 18 and further impinges against a peripheral impact ring 8 to continuously impart strong compression force to the sub- particles on the surfaces of the main particles. At the same time, the powder to be treated is recirculated through a recirculation circuit 13 while carried by a recirculation gas stream to again return to the impact chamber 18 to again receive striking action. As a result, the sub-particles (b) are strongly fixed to the surfaces of the main particles (a).

Description

DETAILED DESCRIPTION OF THE INVENTION According to the present invention, fine particles (hereinafter referred to as child particles) are attached to the surface of a core particle (hereinafter referred to as a mother particle) in advance, or fine particles (hereinafter referred to as child particles) are not attached. The present invention relates to a method and an apparatus for modifying the surface of base particles by embedding or fixing them on the surface of base particles.

Conventionally, various methods have been used to prevent caking of solid particles, prevent discoloration, improve dispersibility, improve fluidity, improve catalytic effect, control digestion and absorption, improve magnetic properties, and improve light resistance. Surface modification methods include physical adsorption, chemical adsorption, vacuum evaporation, and electrostatic adhesion.

Methods such as coating with dissolved substances and special spray drying methods have been used. Among these, in particular, when the surface of solid particles is modified with solid particles, that is, the surface of powder with powder, it is necessary to modify the surface of solid particles with powder for a long period of time (several hours to Modification has been carried out by stirring (for several tens of hours) and applying electrostatic and mechanochemical phenomena that occur with stirring, but the adhesion of the child particles to the mother particles is not sufficient, and as a result, after modification. When processing the powder in the next process, such as mixing, kneading, dispersion, and pasting, the child particles may easily fall off or component segregation may occur, which not only severely limits the operating conditions, but also This was the biggest cause of variations in the quality of subsequent products.

Furthermore, in surface modification of powder-powder systems using the above-mentioned various mixers, ball mills, etc., the fixing force of child particles to the mother particle surface is generally weak, so it is difficult to obtain the desired surface modification. It takes several hours to several tens of hours, and therefore the equipment becomes large and there are problems such as poor processing efficiency.

The present invention has been made in view of the above circumstances, and solves the problems of the prior art, and as shown in FIG. As a result, the surface of the powder particles is uniformly and stably modified in an extremely short period of time (several seconds to several minutes) by forcibly embedding or fixing them using thermal means, thereby improving functionality. The present invention provides a method and an apparatus for obtaining a composite material (hybrid powder), the gist of which is to embed or fix child particles on the surface of a mother particle using an impact-type impact means. A method and apparatus for surface modification of powder particles.

Typical base particle powders that can be surface-treated using the method and apparatus of the present invention generally have a particle size of 0.1 μ to 100 μ.
- Pigments such as titanium dioxide and iron oxide, synthetic polymeric materials such as Epoquin powder, nylon powder, polyethylene powder, and polyethylene powder, and natural materials such as starch, cellulose, and silk powder; A typical child particle powder is a silica colloid particle whose particle size is generally about 0.01 μm to 10 μm.

Alumina colloid particles, titanium dioxide powder/-2 zinc white powder, iron oxide powder, mica powder.

These include natural and synthetic materials such as calcium carbonate powder and barium sulfate, and various synthetic pigments. However, it is not limited to these materials, and includes various chemical industries, electricity, magnetic materials industries, cosmetics, and more! ! ! i-materials, printing inks, toners, coloring materials, textiles, pharmaceuticals, 1 foods.

It can be applied to each combination of components of various materials used in industries such as rubber, plastics, and ceramics.

Generally, the mother particles are large in size and have low hardness, and the child particles are small in size and hard. However, depending on the combination of material particle sizes, the mother and child particles may be reversed. Sometimes it becomes. That is, softer child particles can also be fixed and immobilized on the surface of a harder mother particle.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

Figures 2 and 3 show an example in which an impact crusher is used as the impact impact means. 2 is a rear cover, 3 is a front cover, 4 is a rotary disk that rotates at high speed within the casing 1, and 5 is a plurality of radially arranged around the outer circumference of the rotary disk 4 at predetermined intervals. impact pin, which is generally of hammer or plate type. Reference numeral 6 designates a rotating shaft that rotatably supports the rotary disk 4 within the casing 1, and 8 designates a collision ring that is disposed along the outermost orbital surface of the impact bin 5 and with a certain space therebetween. , this uses various shapes of concave and convex type or circumferential flat plate type. Reference numeral 9 indicates an on-off valve for discharging reformed powder provided by cutting out a part of the collision ring, 10 indicates a valve shaft of the on-off valve 9, and 11 indicates an actuator 213 for operating the on-off valve 9 via the valve shaft 10; is opened in a part of the inner wall of the collision ring 8, and the other end is opened near the center of the rotary disk 4 to form a closed circuit; 14 is a raw material hopper; 15 is a raw material hopper 14 and a circulation circuit 13; 16 is a raw material measuring feeder, and 17 is a raw material storage tank. 1B is a shock chamber provided between the outer periphery of the rotary disk 4 and the collision ring 8, 19 is a circulation port to the circulation circuit 13, 20 is a modified powder discharge shade, 21 is a cyclone, and 22 is a rotary valve,
23 is a bag filter, 24 is a rotary valve, 2
5 is an exhaust fan, 31 is a time-limited tn device for controlling the operation of the device of the present invention, and 32 is a known preprocessor such as various mixers, electric mortars, etc. used when it is necessary to attach child particles to the surface of particles in advance. - are shown respectively.

When carrying out the powder surface modification method of the present invention using the above apparatus, the following procedure is performed.

First, the opening/closing valve 9 for discharging the modified powder is closed, and while introducing an inert gas into the device as necessary, the rotating shaft 6 is driven by a driving means (not shown) to improve the modification powder. Depending on the nature of the material to be treated, it is possible to
The rotary disk 4 is rotated at a circumferential speed of /sec. At this time, as the impact bottle 5 on the outer periphery of the rotary disk 4 rotates, a rapid airflow of air/inert gas is generated, and the circulation port 19 of the circulation circuit 13 opens into the impact chamber 18 due to the fan effect based on the centrifugal force of this airflow. A circulating flow of air flows from the air through the circulation circuit 13 and back to the center of the rotary disk 4, that is, a completely self-circulating flow is formed.

Moreover, since the amount of circulating air generated per unit time is significantly larger than the total volume of the shock chamber and circulation system, a large number of airflow circulation cycles are formed in a short period of time. .

Next, the powder to be treated, in which child particles are attached to the surface of a certain amount of mother particles using, for example, an electrostatic phenomenon, is transferred to the weighing feeder 1.
6, the raw material is put into the raw material hopper 14 in a short time. When it is not necessary to use the preprosensor 27, the mother particles and child particles are weighed side by side and put into the raw material hopper 14. The powder to be processed passes through the shade 15 from the raw material pumper 14 and enters the impact chamber 18 .

The powder particles sent into the impact chamber 18 are instantaneously impacted by a large number of impact bins 5 on the rotary disk 4 that rotates at high speed, and then collide with the surrounding impact ring 8 to impact the surface of the base particles. The child particles are selectively subjected to strong compression. At the same time, the powder to be treated is circulated through the circulation circuit 13 along with the flow of the circulating gas, and returns to the impact chamber 18 again, and once again receives impact action, such impact operations continue in a short period of time. This process is repeated many times, and the child particles are embedded or firmly attached to the surface of the mother particle. This series of impact operations, that is, embedding or fixation of child particles on the surface of the mother particle, is continued until the entire surface of the mother particle is uniformly and firmly immobilized. Since a large amount of gas (air and inert gas) circulates in the system compared to the total volume, the powder to be processed (mother particles and child particles) that circulates with the gas is completely transformed in a very short time. You will receive a number of shocks. - Although it depends on the amount of treatment per batch, the time required for this surface immobilization is generally completed within an extremely short time of several seconds to several minutes, even including the feeding time of the powder to be treated.

FIGS. 1 (1) and (2) show a state in which child particles S, child particles S, and child particles C of different types are made to adhere to mother particle a in advance by static electricity. , As shown in Figures (31 to (5)), the child particles are embedded and fixed to the mother particle a, and further, by changing the supply order of the child particles and the child particles C, (6) to f8 ), different child particles S and C can be fixed to a mother particle a in a single layer or in multiple layers.

After the above immobilization work is completed, the on-off valve 9 for discharging the modified powder is moved to the position shown by the chain line and opened, and the powder subjected to the immobilization process is discharged. This immobilized powder is
Due to the centrifugal force acting on itself (as long as the centrifugal force is acting on the processed powder, the discharge valve 9 may be placed in a different position) and the suction force of the exhaust fan 25,
is discharged from the shock chamber 18 and circulation circuit 13 in several seconds),
Cyclone 2I and circulation circuit 3 through chute 20
The powder is discharged from the system, guided through a chute 20 to a powder collecting device such as a cyclone 21 and a bag filter 23, collected, and discharged to the outside of the system via rotary valves 22 and 24.

After discharging the immobilized powder, the on-off valve 9 is immediately closed, and a certain amount of powder to be treated from the next time onward is supplied to the shock chamber from the metering feeder 16 again, and is immobilized through the same process. powder is produced one after another. Note that these series of batch fixing processing operations are controlled and continued by a time limit control device 31 whose time limit is set in advance in relation to the operating time of related equipment.

If a partial local immobilization process is sufficient for immobilizing the child particles on the surface of the mother particle, the powder impacting apparatus shown in FIG. 2 can also be used as a one-pass continuous processing system. In that case, the powder to be treated may be continuously supplied from the material pumper 15 with the circulation port 19 in FIG. 2 closed and the on-off valve 9 open.

In addition, during the immobilization treatment operation, if it is necessary to use supplementary thermal treatment (for example, when it is necessary to increase the difference in hardness between the mother particles and child particles), the collision ring 8 or the circulation circuit 13 has a jacket structure, and temperature conditions convenient for fixing the powder to be treated can be set through various heating mediums and coolants.

Further, in the powder impact device of the present invention, the rotary disk 4
by attaching an auxiliary blade to the auxiliary blade, or in the middle of the circulation circuit 13,
For example, a centrifugal plate fan or the like may be arranged to further force the circulating flow. That is, if the circulating air volume is increased, the number of times of circulation within a unit time increases, and therefore the number of collisions of powder particles also increases, so that the immobilization processing time can be shortened.

Next, in the powder surface modification (immobilization) work performed in the powder impacting device of the present invention, nitrogen is The case of using various inert gases such as gas will be explained.

FIG. 4 shows an embodiment in which this inert gas is used in a powder impacting device according to the present invention. In explaining this embodiment, the same reference numerals are given to the same members as in the previous embodiment, and explanations will be given. Omitted. In FIG. 4, 26 is a raw material supply valve provided at the bottom of the raw material hopper 14, 27 is an inert gas supply valve that opens into the raw material supply chute 15, 28 is an inert gas supply source, and 29 is an inert gas supply valve. indicates the supply route of
Note that this embodiment shows a mode in which the circulation circuit 13 is housed within the casing l.

When starting the operation, first close the raw material supply valve 26, open the on-off valve 9, and then open the inert gas supply valve 27 to reduce the pressure γ.
The chamber 18 and circulation circuit 13 are filled with inert gas. The substitution of inert gas into the shock chamber and circulation circuit, which is performed prior to the start of this immobilization work, is usually completed within a few minutes.

Next, after closing the on-off valve 9 and the supply valve 27 at the same time, the raw material supply valve 26 is immediately opened and the pre-measured powder to be processed is supplied to the shock chamber 18 through the chute 15. After supplying, the supply valve 26 is immediately returned to the closed state, and upon receiving this signal, the metering feeder 16 measures and supplies the next powder to be processed to the raw material hopper 14.

Thereafter, the powder to be treated is bombarded with an inert gas in the same manner as in the above embodiment, and the powder to be treated is fixed while circulating in the circulation circuit 13 while maintaining sufficient contact with the inert gas. It is processed. Next, when the on-off valve 9 and the supply valve 27 are opened, the immobilized powder is transferred to the shock chamber 18 and the circulation circuit 13.
is discharged into the chute 20, and at the same time the shock chamber 18 and circulation circuit 13 are replaced with fresh inert gas. The discharged fixed powder is treated in the same manner as in the previous example.

After that, close the on-off valve 9 and the supply valve 27 and open the raw material supply valve 26.
If it is opened, the next immobilization processing operation will proceed. Note that this series of batch fixing operations including supply and stop of inert gas are controlled and continued by the time control device 31 as in the previous embodiment.

If the child particles are immobilized on the surface of the mother particle by local immobilization treatment, the powder impacting apparatus shown in FIG. 4 can be used as a one-pass continuous processing system. In that case, the circulation circuit 13 shown in FIG. It should be supplied at a ratio of . At this time, use the exhaust fan (second
If the method shown in 25) in the figure is to return the inert gas at the outlet to the raw material supply chute 15, the amount of inert gas used can be reduced, which is economical.

As mentioned above, the features of the method and device for surface modification of solid (powder) particles according to the present invention are that the impact type crushing mechanism as an impact impact means has a strong impact force on the fine powder particles; Focusing on the difference in hardness between the mother particle and child particles, the size of the impact force itself and the number of impacts can be arbitrarily adjusted to apply impact force to the entire surface of the mother particle having a certain shape. .

Furthermore, according to the method and apparatus of the present invention as shown in FIG.
The immobilization of child particles to the mother particles of various materials is limited to the immobilization of a single particle layer using simple single-component child particles, the immobilization of child particles of two or more components, and furthermore, the immobilization of child particles of two or more components. It can be fixed in multiple layers.

Furthermore, according to the method and apparatus of the present invention, when the proportion (ratio) of immobilized particles to each base particle does not need to be so strict (that is, when the overall component ratio only needs to be constant), , various mixers.

It is possible to immobilize the child particles on the surface of the mother particle by directly supplying separately measured mother particle powder and child particle powder to the impact chamber without using a preprocessor such as an electric mortar.

As described above, according to the method and apparatus for surface modification of solid particles according to the present invention, child particles are embedded in or firmly fixed to the mother particles made of a combination of various powder materials. Through modification treatment, functional composite/hybrid powder materials (composite or hybrid powder) with uniform and stable properties can be efficiently produced in an extremely short time.

Furthermore, the solid particle surface modification device according to the present invention has a very simple structure of the impact chamber and circulation circuit, and can be easily disassembled by removing the rotary disk 4 by opening the front cover. Therefore, it is extremely easy to inspect and clean the inside of the device, and by avoiding the contamination of foreign matter when changing types, the device can be used for surface modification treatment of a wide range of types of powder materials.

Furthermore, even when using an inert gas, the amount used can be minimized efficiently.

Example 1 A second example in which the outer diameter of the eight plate-type impact bins installed around the rotary disk is 235 fl, and the diameter of the circulation circuit is 54.9 ms.
The powder impact device shown in the figure was used. Average particle size d as a base particle
Average particle size d on the surface of p50-5μ spherical nylon 12
As a result of immobilizing ordered mixtures in which titanium dioxide child particles with p50-0.3μ- were attached in advance using a mixer under the treatment conditions shown in the table below, titanium dioxide (child particles) was mixed with nylon 12 (mother particles). A uniformly stable powder of nylon 12 surface-modified with titanium dioxide was obtained, which was embedded or firmly fixed on the surface of the nylon 12 (core particles).

Calculated from the internal volume of a titanium dioxide-fixed irreli luster circuit with a core made of nylon 120.

Incidentally, scanning electron micrographs of the immobilized and modified powders obtained in the above Examples (T-3 and T-4) are shown in FIG.

[Brief explanation of drawings]

Fig. 1 (11 to (8)) is a conceptual explanatory diagram showing various modified ground powders processed by the method and apparatus according to the present invention and the form of the powder after modification and immobilization. , a conceptual explanatory diagram systematically showing one embodiment of the powder impact device according to the present invention together with its front and rear devices; FIG. 3 is a side cross-sectional explanatory diagram of FIG. 2;
The figure is an explanatory diagram of another example in which an inert gas is used, and Figure 5 shows a scanning electron micrograph of the powder after surface modification, and Figure (1) is a 6000x magnification. Figure (2) shows a magnification of 20,000 times, and Figure (3) shows a magnification of 40,000 times. a... Mother particle, b, c... Child particle, l...
・Impact crusher. Figure i; Lambda procedural amendment letter 岨燦 December 3, 1985 1, Indication of the case Patent Application No. 223158 of 1985 2, Name of the invention Method and apparatus for surface modification of solid particles 3, Relationship with the case of the person making the amendment Patent applicant name Nara Kikai Seisakusho Co., Ltd. 4, Agent 107 (and 2 others) 5. Specification of contents of amendment subject to amendment, page 12, between line 1O and line 1+ Add the following to . Furthermore, the powder impacting device of the present invention is not only equipped with the above-mentioned circulation circuit, but also the structure of the device shown in FIGS. 2 and 3 with the circulation circuit removed. be able to. Procedural amendment form) % form % Mr. Michibe Uga, Commissioner of the Patent Office, 1.
Display of the case 1985 Patent Application No. 223158 2 Name of the invention Method for surface modification of solid particles and its device 3 Person making the amendment Relationship with the case Patent applicant name Nara Kikai Seisakusho Co., Ltd. 4, Agent 〒 107 (2 others) 6. Subject of amendment “Brief explanation of drawings” in the specification
column. The statement ``Figure 5 shows a scanning electron*i mirror photograph of the powder after surface modification'' on page 19, lines 12 to 13 of the description of the amendment is corrected as follows. Figure 5 shows a scanning electron micrograph to show the particle structure of the powder after surface modification,

Claims (8)

[Claims] (1) A method and apparatus for surface modification of solid particles, characterized by embedding or fixing other solid particles on the surface of solid particles using an impact-type impact means. (2) The method and apparatus for surface modification of solid particles according to claim (1), characterized in that other solid particles are attached to the surface of the solid particles in advance. (3) Claims (1) or (2) characterized in that the particles are fused together by heating as an auxiliary means.
A method for surface modification of solid particles and an apparatus therefor described in Section 1. (4) A method for surface reforming solid particles according to any one of claims (1) to (3), characterized in that the embedding or fixing step is performed under an inert gas atmosphere. and its equipment. (5) It is characterized by comprising an impact chamber provided with an impact impact means, a supply port for feeding solid particles and other solid particles into the chamber, and a circulation path communicating from the outlet of the impact chamber to the supply port. surface modification of solid particles and its equipment. (6) The method and apparatus for surface modification of solid particles according to claim (5), characterized in that the method includes heating means. (7) The method and apparatus for surface modification of solid particles according to claim (5) or (6), characterized in that the method includes an inert gas supply means. (8) The method and apparatus for surface modification of solid particles according to claim (5), which is an impact crusher.