JPS62298443A - Method for reforming surface of solid particle - Google Patents

Abstract

PURPOSE:To form a functional composite and mixed material by filling other solid particles in the recessed of a solid particle having ruggedness of various shapes on the surface, and exerting impact on the particle to soften, melt, and deform the solid particle. CONSTITUTION:Powder to be treated obtained by depositing child particles on the surface of a fixed amt. of mother particles, for example, by utilizing an electrostatic phenomenon is charged in a raw material hopper 14 from a weight-feeder 16 in a short time. The power to be treated enters an impact chamber 18 through a chute 15. In the impact chamber, a group of powdery particles is instantaneously hit by many impact pins 5 of a rotary disk 4 rotating at high speed, further collided with a collision ring 8, and again impacted and strongly compressed. Consequently, the surface of the mother particle, especially the protrusion of the mother particle, is softened, melted, and deformed in a short time, the child particles (b) are occuluded in the mother particle (a), and the film due to the mother particle is formed on the surface of the mother particle.

Description

[Detailed Description of the Invention] 3. Detailed Description of the Invention a. Industrial Application Field The present invention provides core particles (hereinafter referred to as base particles) as
Its surface has various shapes of unevenness and thank you notes.

Using particles with a groove-like shape, other fine particles (hereinafter referred to as child particles) are attached and embedded in advance on the surface or concave portions of this mother particle, and then the convex portions of this mother particle are It relates to a method of modifying the surface of mother particles by softening, melting, and deforming the mother particles and enveloping the child particles in the mother particles.

b. Conventional technology Conventionally, in general, prevention of caking of solid particles, prevention of discoloration and deterioration, 1 improvement of dispersibility, improvement of fluidity, improvement of catalytic effect, control of digestion and absorption, improvement of magnetic properties, 1 improvement of color development, Various surface modifications are used to improve light resistance, such as physical adsorption, chemical adsorption, and vacuum evaporation.

Methods such as electrostatic deposition, 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 the electrostatic and mechanochemical phenomena that occur with stirring.

C0 Problems to be Solved by the Invention In the conventional method, the child particles are only attached around the mother particles, but the adhesion of the child particles to the mother particles is not sufficient. When processes such as mixing, kneading, dispersion, and pasting are performed in the next process, child particles may easily fall off or component segregation may occur, which not only severely limits the operating conditions, but also affects the product after processing. This was the biggest cause of variation in quality.

Furthermore, various microencapsulation methods have been used to control the sustained release of substances, but all of them are wet methods, and not only do they require a drying process as the next step, but the field of application of the technology is also limited. It was limited and lacked versatility.

The present invention has been made in view of the above-mentioned circumstances, and it is an object of the present invention to provide a method for surface modification of solid particles that solves the above-mentioned problems of the prior art.

d. Means for Solving the Problems In order to solve the above-mentioned problems, the present invention, as shown in FIG. ,? 8 melt.

Alternatively, by deforming the mother particles and enveloping the child particles in the mother particles, the surface of the powder particles can be uniformly and stably modified in an extremely short period of time (several seconds to several minutes), thereby creating a functional composite material (hybrid powder). The main purpose of this method is to use particles with various surface shapes such as irregularities, bow-like shapes, and grooves as base particles, and to apply other materials to the surfaces and depressions of the base particles in advance. A method of producing powder particles characterized by attaching and embedding the child particles, and further softening, melting, and deforming the protrusions of the mother particles using an impact impact means to envelop the child particles in the mother particles. In the surface modification method.

Typical base particle powders that can be surface-treated by the method of the present invention generally have a particle size of about 0.1 μ1) to 100 μ-, and the particle surface morphology is variously shaped as uneven, bow-like, or groove-like. Nylon powder, polyethylene powder, acrylic powder, styrene powder.

ABS powder, polypropylene powder, gelatin,
Organic substances, inorganic substances, metals such as various waxes, sulfur, copper powder, silver powder, etc., and typical child particle powders include titanium dioxide and carbon whose particle size is generally about 0.01 μa1 to 10 μm. , pigments such as iron oxide, epoxy powder, nylon powder.

Polymer materials such as acrylic powder, soot, and silver.

These include metals such as copper, natural materials such as starch, cellulose, silk powder, and ceramics, and various powdered fragrances. However, the present invention is not limited to these materials, and can be applied to various chemical industries and electrical industries.

Applicable to various combinations of materials used in industries such as magnetic materials, cosmetics, paints, printing inks, toners, coloring materials, fibers, pharmaceuticals, foods, rubber, plastics, and ceramics. Can be done.

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

FIGS. 2 and 3 show an example in which an impact crusher is used as impact impact means for carrying out the method of the present invention. In the figure, 1 is a casing of a powder impacting device (a typical impact type crusher) used to carry out the method of the present invention, and 2
is the rear cover, 3 is the front cover, 4 is the casing 1
A rotary disk 5 is located inside and rotates at high speed, and reference numeral 5 indicates a plurality of impact pins arranged radially around the outer periphery of the rotary disk 4 at predetermined intervals, which are hammer-shaped or plate-shaped. . 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 denotes an on-off valve for discharging the modified powder, which is provided by cutting out a part of the collision ring. Depending on the case, this may be provided by cutting out a part of the front cover or the rear cover facing the crushing chamber. 10 is the valve stem of the on-off valve 9, 1) is the valve stem 10
An actuator 13 operates the on-off valve 9 through a circulating circuit 14 whose one end opens in a part of the inner wall of the collision ring 8 and the other end opens near the center of the rotary disk 4 to form a closed circuit. 1 is a raw material hopper, 15 is a raw material supply shade that connects the raw material hopper 14 and the circulation circuit 13, 16 is a raw material measuring feeder, and 17 is a raw material storage tank. 18 is a shock chamber provided between the outer periphery of the rotary disk 4 and the collision ring 8;
19 indicates circulation ports to the circulation circuit 13, 20 indicates a modified powder discharge chute, 21 indicates a cyclone, 22 indicates a rotary valve, 23 indicates a bag filter, 24 indicates a rotary valve, 25 indicates an exhaust fan, and 31 indicates the present invention. A time control device 32 for controlling the operation of the device indicates various types of mixers, electric mortars, and other known preprosensors used when it is necessary to attach child particles to the surface of mother particles in advance.

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. 5 Mongolia/see = 16 depending on the nature of the material to be treated
The rotary disk 4 is rotated at a circumferential speed of 0v/see. At this time, a rapid airflow of air/inert gas is generated as the impact pin 5 on the outer periphery of the rotary disk 4 rotates, and 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 circulation port 19 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 per unit time generated at this time is significantly larger than the total volume of the shock chamber and circulation system, a large number of air 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 hopper 14 in a short time. When it is not necessary to use the preprocessor 32, the mother particles and child particles are weighed separately and placed into the raw material hopper 14. The powder to be processed passes through the chute 15 from the raw material pumper 14 and enters the shock chamber 18 .

The powder particles sent into the impact chamber 18 are instantaneously impacted by a large number of impact pins 5 of the rotary disk 4 that rotates at high speed, and then collide with the surrounding impact ring 8 to be impacted again. and is subjected to strong compressive action. At the same time, the powder to be treated is circulated through the circulation circuit 13 along with the flow of the circulating gas, returns to the impact chamber 18, and is again subjected to the impact action.

This kind of impact work is repeated many times in a row in a short period of time, and the surface of the base particle, especially the convex part of the base particle, is softened in a short period of time due to the (thermal) energy received from the impact and impact action. , f@melting and deformation, and a film of the mother particles is formed on the surface of the mother particles with the child particles wrapped in the mother particles. This series of impact actions is continued until the entire surface of the base particles is in the desired fused state, but a large amount of gas (air and inert gas) is inside the system compared to the total volume of the impact chamber and circulation system. As a result, the powder to be treated (mother particles and child particles) that circulates together with the gas is subjected to a large number of shocks in an extremely short period of time. -Depending on the batch processing volume,
The time required for this surface modification, including the time for supplying the powder to be treated, is generally completed within an extremely short time of several seconds to several minutes.

In Figure 1, which shows a model diagram, a is the base particle, and its surface morphology includes various shapes of irregularities and thank-you notes.

It has a groove-like shape. b is a child particle. Design +1) shows the raw material system, design (2) shows the state in which the child particles are attached to the concave portions of the mother particles, and in this state, the impact,
By applying a striking action, a part (convex part) of the mother particle softens, melts, or deforms, and the particle moves as shown in FIG.

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, (
The shock chamber 18 and the circulation circuit 13 are exhausted in a few seconds),
Cyclone 21 and circulation circuit 13 pass through chute 20
The powder is discharged through the shade 2o, guided to a powder collection device such as a cyclone 21 and a bag filter 23, collected, and discharged outside 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 the 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. Treated powder is produced one after another. Note that these series of batch fixing processing operations are controlled and continued by a time limit control bag W31 whose time limit is set in advance in relation to the operating time of related equipment.

If the softening, melting and film-forming treatment by the mother particle on the surface of the mother particle can be done by partial local fixation treatment, powder technique w1 in Fig. 2 can be used.
The device can also be used as a one-bath 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 surface modification treatment operation according to the present invention, if it is necessary to use thermal treatment in combination, the collision ring 8 and the circulation circuit 13 can be made into a jacket structure, and the powder to be treated can be passed through various heating mediums and coolants. Temperature conditions convenient for surface modification treatment can be set.

Furthermore, in the powder impact device used to carry out the present invention,
The rotary disk 4 is equipped with auxiliary blades, or the circulation circuit 1
For example, a centrifugal plate fan or the like may be disposed in the middle of the circulation flow to further apply force to the circulating flow. That is, if the circulating air volume is increased, the number of circulations per unit time increases, and therefore the number of collisions of powder particles also increases, so that the surface modification treatment time can be shortened.

Furthermore, the powder impacting device used in carrying out the present invention is not limited to the one equipped with the above-mentioned circulation circuit (it also includes the structure in which the circulation circuit has been removed from the devices shown in FIGS. 2 and 3). can be used.

Also, regarding the atmosphere in which the present invention is carried out,
Combination of particles prevents oxidative deterioration.

Nitrogen gas or various inert gases may be used to prevent ignition or explosion.

FIG. 4 shows an example in which this inert gas is used in a powder impacting device that is also used in the practice of the present invention. In explaining this example, the same members as those in the previous example are given the same reference numerals. , the explanation is omitted. In Figure 4, 26
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 path. Note that this embodiment shows an embodiment in which the circulation circuit 13 is housed within the casing 1.

When starting 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 fill the shock chamber 18 and circulation circuit 13 with inert gas. The replacement of inert gas into the shock chamber and circulation circuit, which is carried out prior to the start of the oxidation 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 treated 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 reformed while being circulated in the circulation circuit 13 while maintaining sufficient contact with the inert gas. When the on-off valve 9 and the supply valve 27 are opened, the powder that has been fixed is discharged from the shock chamber 18 and the circulation circuit 13 to the shade 20, and at the same time the shock chamber 18 and the circulation circuit 13 are opened. It is replaced with a suitable inert gas. The discharged surface-modified 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 reforming operation will proceed. Note that this series of batch fixing operations including supplying and stopping the inert gas are controlled by the time control device 31 and set to mVt, as in the previous embodiment.

If the softening, melting, or deformation of the base particles only needs to be done in a localized area, the powder impacting apparatus shown in FIG. 4 can be used as a one-pass continuous treatment system. In that case, the circulation circuit 13 shown in FIG. 4 is closed, and the powder to be processed is continuously fed in a constant amount from the raw material hopper 14 with the raw material supply valve 26, the inert gas supply valve 27, and the on-off valve 9 open. In this case, the inert gas at the outlet of the exhaust fan (25 in Figure 2) should be supplied to the raw material supply chute 15.
If the method is adopted, the amount of inert gas used will be reduced and it will be economical.

As mentioned above, the features of the method for surface modification of solid (powder) particles according to the present invention are that the impact-type crushing mechanism as an impact-type impact means has a strong impact force on the fine powder particles, and the base particles used The idea is to focus on the surface morphology of the parent particles and use impact force to envelop the child particles within the parent particles.

Furthermore, as shown in Fig. 1, according to the method of the present invention, the envelopment of the child particles into the mother particles of various materials is not limited to just one-component molecular particles, but it is also possible to enclose child particles of two or more components. It is. Further, the shape of the child particles is not restricted, such as spherical, amorphous, and fibrous.

Furthermore, according to the method of the present invention, when the ratio (ratio) of the contained child particles to each parent particle does not have to be so strict (
In other words, when it is sufficient that the overall component ratio is constant)
This method does not use pre-processors such as various mixers or electric mortars, but directly supplies separately weighed mother particle powder and child particle powder to the impact chamber to immobilize the child particles on the surface of the mother particle. can be done.

Example 1 The outer diameter of the 8 plate-type impact pins installed around the rotary disk is 235 cm, and the diameter of the I-circuit is 54.9 sm.
The powder impact device shown in the figure was used. Average particle size d as a base particle
Acetylene black of steel with an average particle size di) so = 0.03μ is mixed and deposited on porous nylon 6 with an average particle size of 19μ as child particles using a mixer, and then processed using the above processing device at a rotation speed of 654Orpm and powder charge amount. When processed under the conditions of 120 g and an operating time of 2 sin, a surface-modified powder was obtained in which acetylene blanks (child particles) were wrapped in nylon particles (mother particles), and the surface was further covered with nylon 6. .

Incidentally, a scanning electron micrograph of the powder sample used in the above example is shown in FIG.

e. Effects of the Invention As described above, according to the method for surface modification of solid particles according to the present invention, the surface morphology of the mother particles made of a combination of various powder materials is utilized to modify other child particles. By performing a surface modification treatment that envelops the particles in the mother particles, it is possible to efficiently produce functional composite/hybrid powder materials (composite or hybrid powder) with uniform and stable properties in an extremely short time.

[Brief explanation of drawings]

FIGS. 1 (1) to (4) are conceptual explanatory diagrams showing the aspects of various pre-modified powders and modified powders treated by the method according to the present invention, and FIG. A conceptual explanatory diagram systematically showing the powder impacting device used in the implementation, together with its front and rear devices, Figure 3 is a side cross-sectional diagram of Figure 2, and Figure 4 is a case in which inert gas is also used. Figure 5 shows a scanning electron micrograph of the powder sample used in the example, and Figure (1) shows the porous nylon raw material used in the example (2000x magnification). ), (21 indicates a state in which child particles are attached to a mother particle (5000 times), +31 indicates a state in which the child particles are wrapped in the mother particle by surface modification by impact impact means (5000 times). a. ...mother particle, b...child particle, 1...
Impact crusher. Figure 1 Procedural amendment adjustable type) September 5, 1988 Patent Application No. 140993 of 1988 2, Title of invention Method for surface modification of solid particles 3, Relationship with the person making the amendment Name of patent applicant Stocks Company: Nara Kikai Seisakusho 4, Agent: 107 (and 2 others) 5. Date of amendment order: August 6, 1985 (Shipping date: August 26, 1986) 6. Subject of amendment: Brief description of drawings in the specification An explanation column. Contents of the amendment 1) "Scanning electron micrograph of powder sample" on page 17, line 16 of the specification is corrected to "scanning electron micrograph of particle structure of powder sample."that's all

Claims (4)

[Claims] (1) Embed other solid particles into the recesses of solid particles that have various shapes of unevenness, holes, and grooves on the surface, and soften, melt, and deform these solid particles using an impact method to form other solid particles. A method for surface modification of solid particles, characterized by bringing them into an encapsulated state. (2) The method 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.
The method for surface modification of solid particles described in Section 1. (4) A method for surface modification of solid particles according to any one of claims (1) to (3), characterized in that the method is carried out under an inert gas atmosphere.