JP4397003B2 - Powder immobilization method and powder immobilization product - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for fixing powder to a substrate and a powder-immobilized product, and more particularly, to a method for easily fixing powder without using a large-scale apparatus and a powder-immobilized product obtained by the method. .
[0002]
[Prior art and problems to be solved by the invention]
In order to impart various functions to a substrate, a material whose surface has been modified has attracted attention. For example, titanium oxide, known as a photocatalyst, generates active oxygen from oxygen and water in the air using the energy of ultraviolet rays, and decomposes and sterilizes various organic substances adhering to the surface by its strong oxidizing power, and smells It has an action of decomposing the components. Therefore, antibacterial properties, deodorizing functions, and antifouling functions can be imparted by immobilizing titanium oxide powder on the substrate surface. Moreover, since hydroxyapatite, silica, zeolite, etc. have various adsorption characteristics, the function as an adsorbent can be imparted by immobilizing them on the substrate surface. Besides these, a new function can be imparted to the substrate surface by immobilizing various substances on the substrate surface.
[0003]
In order to immobilize powders with various functions on the surface of the base material, the powder is embedded in the base material by applying it to the surface of the base material using an adhesive or an adhesive substance, or by applying a strong impact force. And the like (physical immobilization method) have been used. However, in the former, the adhesive strength is weak, heat resistance may be a problem, and it is expected that the fixed powder will be detached, and in the latter, a device for applying a strong impact force becomes large. Or the type of powder or substrate is limited.
[0004]
There is also a method of spraying and fixing the powder onto the base material by thermal spraying, but since the spraying power is large, the powder penetrates into the base material and the ratio of the powder bare on the surface is reduced. Furthermore, deformation of the base material occurs, which is not preferable.
[0005]
In addition to the above example, Japanese Patent Application No. 11-361100 discloses a method of embedding a base material in powder and heat-treating it under pressure to fix the powder on the base material. ing. However, with this method, it is difficult to continue the pressurization during the heat treatment, and stability (reproducibility) may be lacking.
[0006]
Accordingly, an object of the present invention is to provide a method for easily and stably immobilizing powder on a substrate (with good reproducibility) without requiring a large-scale apparatus, and a powder-immobilized product obtained by the method. That is.
[0007]
[Means for Solving the Problems]
As a result of diligent research in view of the above problems, the present inventors made a green compact by pressing in a state where the base material was embedded in a powder that had been calcined at a predetermined temperature, It was discovered that heat treatment above the softening point would stably stabilize the powder on the substrate, leading to the present invention.
[0008]
That is, in the method for immobilizing a powder of the present invention, a green compact is produced by pressing in a state where the base material is embedded in the powder, and the green compact is heat-treated at a temperature equal to or higher than the softening point of the base material. The powder is fixed on the substrate.
[0009]
It is preferable to pressurize at a pressure of 10 kgf / cm ^{2 to 2} tf / cm ² . The substrate is preferably made of glass or a polymer material. The powder is preferably calcined at a temperature equal to or higher than the heat treatment temperature. The powder is oxide powder, nitride powder, carbide powder, calcium phosphate powder, or a mixture of two or more thereof. It is preferable that
[0011]
DETAILED DESCRIPTION OF THE INVENTION
The method for immobilizing powder of the present invention is to stably immobilize powder on the surface of a substrate. Hereinafter, the powder immobilization method of the present invention and the powder immobilization product obtained by the method will be described in detail with reference to FIG. 1 and FIG.
[0012]
[1] powders and substrates
(1) Powder The powder 3 used in the present invention includes oxide powder such as alumina and titania, nitride powder such as silicon nitride and titanium nitride, carbide powder such as silicon carbide and tungsten carbide, or hydroxy Any calcium phosphate powder such as apatite or a combination of two or more of these may be used.
[0013]
Prior to embedding the base material 2 to form the green compact 1, the powder 3 is calcined to a temperature equal to or higher than the heat treatment temperature for immobilization. When the green compact 1 is produced using the powder 3 that is not calcined and subjected to heat treatment, the green compact 1 contracts, and fine protrusions are formed on the surface of the substrate, resulting in cracks and the like. It is. Specifically, although it depends on various conditions such as the base material 2 and the powder 3 to be fixed, it is preferable to calcine within the range of the heat treatment temperature to the heat treatment temperature + 300 ° C.
[0014]
The particle size of the powder 3 to be used is not particularly limited, but it is preferable to use a powder having a particle size of 5 nm to 100 μm in consideration of ease of handling. Multilayer formation is possible by controlling the particle size of the powder 3 or selecting the type of the powder 3 as appropriate. For example, the smaller the particle size, the thinner the powder fixed layer.
[0015]
(2) Substrate In the method for immobilizing powder according to the present invention, the powder 3 is immobilized on the surface of the substrate 2 by heat treatment above the softening point of the substrate 2. That is, the base material 2 expands due to softening during heating, and the powder 3 in the green compact 1 is fixed by getting into the surface of the base material 2. Accordingly, any material having a softening point can be used. Specifically, a substrate made of a polymer substance such as glass, polyethylene, or polycarbonate can be used.
[0016]
Further, the shape of the substrate 2 is not particularly limited. In the method of the present invention, as shown in FIG. 1, the base material 2 is embedded in the green compact 1, so that the powder 3 becomes uniform throughout the base material 2 due to the residual stress in the green compact 1. When pressed, a part of the powder 3 enters and is fixed so that the surface of the base material 2 is hard to get into. Therefore, the powder 3 can be fixed on the surface of any shape. Moreover, what is necessary is just to mask the part which is not fixed, when fixing the powder 3 only to a part of base material 2. FIG. Thereby, a part of the surface of the base material 2 can be selectively functionalized with the immobilized powder.
[0017]
[2] Method for immobilizing powder The pre-fired powder 3 is filled in a container made of alumina or the like, and the substrate 2 is placed thereon. Further, the powder 3 is filled thereon. At this time, it is preferable to install the base material 2 so as to be positioned at the center of the filled powder 3.
[0018]
Then a hand press, uniaxial pressing or using isostatic pressing or the like, lightly pressed by applying a pressure of ^{10kgf / cm 2 ~2tf / cm 2} , to produce a powder compact 1 as shown in FIG. The applied pressure is not particularly limited as long as the base material 2 is not deformed even if it is greater than ² tf / cm ² . As shown in FIG. 1, the green compact 1 is embedded in the vicinity of the center of the powder 3 on which the base material 2 is fixed.
[0019]
After pressing, the green compact 1 is taken out and heat treated in an atmospheric furnace. The heat treatment temperature is preferably not less than the softening point of the substrate 2 and not more than the calcining temperature of the powder 3. Here, the heat treatment time is preferably 5 to 10 minutes. If it is shorter than 5 minutes, the powder 3 is not sufficiently fixed, and if it is longer than 10 minutes, the substrate 2 is deformed, which is not preferable. In the present invention, since the heat treatment time is short, not only the deformation of the substrate 2 can be prevented, but also the overall production time can be shortened. Further, since it is not necessary to pressurize during the heat treatment, the operation is simple and the reproducibility is excellent.
[0020]
After the heat treatment, the substrate 2 is taken out and taken out, and the particles 3 ′ that are excessively adhered to the surface are removed by an ultrasonic cleaner or a brush. Then, the particles 3 ′ are fixed on the surface of the substrate 2 by powder fixation. The compound is obtained (FIG. 2).
[0021]
[3] Powder Immobilized Product FIG. 2 shows an example of the powder immobilized product obtained by the powder immobilization method of the present invention. The powder-immobilized product obtained by the method of the present invention enters the surface of the base material 2 expanded by the heat treatment so that the particles 3 ′ bite into it, and when the base material 2 returns to the original state by subsequent cooling. The particles 3 ′ entering the surface are strongly fixed.
[0022]
Therefore, as shown in FIG. 2 (a), the powder-immobilized product of the present invention has a part of the particles 3 'entered from the substrate surface into the interior and immobilized. As shown in FIG. 2 (b), the immobilized particles 3 'are dispersed on the surface of the base material and are bare. Note that the size of the particle 3 ′ shown in FIG. 2 is exaggerated for easy understanding.
[0023]
【Example】
The present invention will be described in more detail with reference to the following examples, but the present invention is not limited thereto.
[0024]
Example 1
30 g of hydroxyapatite powder (particle size 4-5 μm) calcined at 750 ° C. for 1 hour in an alumina container (dimensions: 3 cm inside diameter, 10 cm deep, the same for the following examples and comparative examples) Then, a 1 cm square glass cube (low melting point glass having a softening point of 450 ° C.) was installed. Further, 30 g of the hydroxyapatite powder was filled thereon, and the periphery was covered with the hydroxyapatite powder so that the glass cube was at the center. Thereafter, it was pressed (200 kgf / cm ² ) using a hand press machine to produce a green compact. The green compact was placed in an atmospheric furnace and heat treated at 550 ° C. for 10 minutes.
[0025]
After the heat treatment, the green compact was taken out from the atmospheric furnace and allowed to cool naturally, and then the excessively adhered particles on the surface were removed using an ultrasonic cleaner. In the obtained immobilized glass cube, hydroxyapatite particles were immobilized only on the surface, and they were in a bare state.
[0026]
Example 2
Titanium oxide powder (ST-01 anatase type, average particle size 7 nm, manufactured by Ishihara Techno Co., Ltd.) calcined at 600 ° C. for 1 hour in an alumina container is filled with 20 g, and then a 1 cm square glass cube (softening point) 450 ° C. low melting glass). Further, 20 g of the titanium oxide powder was filled thereon, and the periphery was covered with the titanium oxide powder so that the glass cube was at the center. Thereafter, it was pressed (100 kgf / cm ² ) using a hand press machine to produce a green compact. The green compact was placed in an atmospheric furnace and heat treated at 550 ° C. for 10 minutes.
[0027]
After the heat treatment, the green compact was taken out from the atmospheric furnace and allowed to cool naturally, and then the excessively adhered particles on the surface were removed using an ultrasonic cleaner. The obtained immobilized glass cube had titanium oxide particles immobilized only on the surface, and they were in a bare state.
[0028]
Example 3
An alumina container was filled with 30 g of hydroxyapatite powder (average particle size 40 μm) calcined at 750 ° C. for 1 hour, and then a glass sphere having a diameter of φ8 mm (low melting glass having a softening point of 450 ° C.) was installed. Further, 30 g of the hydroxyapatite powder was filled thereon, and the periphery was covered with the hydroxyapatite powder so that the glass sphere was centered. Thereafter, it was pressed (300 kgf / cm ² ) using a hand press machine to produce a green compact. The green compact was placed in an atmospheric furnace and heat treated at 550 ° C. for 10 minutes.
[0029]
After the heat treatment, the green compact was taken out from the atmospheric furnace and allowed to cool naturally, and then the excessively adhered particles on the surface were removed using an ultrasonic cleaner. In the obtained immobilized glass sphere, hydroxyapatite particles were immobilized only on the surface, and they were in a bare state.
[0030]
Example 4
Filled with 30 g of hydroxyapatite powder (average particle size 80 μm) calcined at 750 ° C. for 1 hour in an alumina container, then 12 mm × 20 mm glass substrate (low melting glass with softening point 450 ° C.) Was installed. Further, 30 g of the hydroxyapatite powder was filled thereon, and the periphery was covered with the hydroxyapatite powder so that the glass substrate was at the center. Thereafter, it was pressed (300 kgf / cm ² ) using a hand press machine to produce a green compact. The green compact was placed in an atmospheric furnace and heat treated at 550 ° C. for 10 minutes.
[0031]
After the heat treatment, the green compact was taken out from the atmospheric furnace and allowed to cool naturally, and then the excessively adhered particles on the surface were removed using an ultrasonic cleaner. The obtained immobilized glass substrate had hydroxyapatite particles immobilized only on the surface thereof, and was in a bare state.
[0032]
Example 5
An alumina container is filled with 30 g of α-alumina powder (particle size 2 to 3 μm) calcined at 800 ° C. for 1 hour, and then a glass substrate (softening point 708 ° C. borosilicate with a thickness of 12 mm × 20 mm) Glass) was installed. Further, 30 g of the α-alumina powder was filled thereon, and the periphery was covered with the α-alumina powder so that the glass substrate was at the center. Thereafter, it was pressed (200 kgf / cm ² ) using a hand press machine to produce a green compact. The green compact was placed in an atmospheric furnace and heat treated at 750 ° C. for 10 minutes.
[0033]
After the heat treatment, the green compact was taken out from the atmospheric furnace and allowed to cool naturally, and then the excessively adhered particles on the surface were removed using an ultrasonic cleaner. The obtained immobilized glass substrate had α-alumina particles immobilized only on the surface, and they were in a bare state.
Comparative example 30 g of hydroxyapatite powder (particle size: 4-5 μm) was filled in an alumina container, and then a glass substrate (low melting glass with 10 mm × 20 mm, thickness 1 mm, softening point 450 ° C.). installed. Further, 30 g of the hydroxyapatite powder was filled thereon, and the periphery was covered with the hydroxyapatite powder so that the glass substrate was centered.
[0034]
Then, it was put into an atmospheric furnace with no press pressure applied and subjected to heat treatment at 550 ° C. for 10 minutes.
[0035]
After the heat treatment, the green compact was taken out from the atmospheric furnace, allowed to cool naturally, and then the particles excessively adhered on the substrate surface were removed using an ultrasonic cleaner. Nothing was fixed on the obtained glass substrate, and it was in the same state as before the heat treatment.
[0036]
【The invention's effect】
As described above in detail, according to the method for immobilizing a powder of the present invention, sufficient heat resistance can be secured, the powder is not detached, and a large apparatus is not required. In addition, any base material having softening properties can be applied, and the powder to be immobilized is hardly restricted as long as the powder is stable with respect to the processing temperature. In particular, a stable immobilization product can be obtained by compacting even a fine powder that is difficult to immobilize. Furthermore, since it is not necessary to apply pressure during the heat treatment, the treatment is simple, the stability is high, and the shape as it is before and after the treatment can be maintained without deformation of the base material. In addition, the powder can be fixed to a substrate having various shapes such as a normal plate shape, a cube, a sphere, and the like.
[Brief description of the drawings]
FIG. 1 is a view showing an example of a cross section of a green compact obtained by the method of the present invention.
FIG. 2 is a diagram showing an example of a powder fixed product obtained by the method of the present invention, in which (a) shows a partial cross section of the powder fixed product, and (b) shows the surface of the powder fixed product.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Green compact 2 ... Base material 3 ... Powder 3 '.. Particle

Claims (5)

Pressing with the base material embedded in the powder to produce a green compact, heat-treating the green compact above the softening point of the base material, and fixing the powder on the base material A method for immobilizing powder characterized by the above. In the immobilization method of the powder of claim 1, 10 kgf / cm ² immobilization method of a powder, characterized in that pressurizing at a pressure of ~2tf / cm ^2.   3. The method for immobilizing powder according to claim 2, wherein the substrate is glass or a polymer material.   4. The method for immobilizing powder according to claim 1, wherein the powder is calcined at a temperature equal to or higher than the heat treatment temperature.   5. The method for immobilizing powder according to claim 1, wherein the powder is one of oxide powder, nitride powder, carbide powder, calcium phosphate powder, or two or more of these. A method for immobilizing powder, comprising mixing.

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