Method for manufacturing porous structure

Abstract

The present invention provides composite particles that enable a porous member to be produced in a shorter time, or a porous member or porous structure that can be produced in a shorter time, or a method for producing a porous structure. The composite particle 1 is made of a core material 2 and a polymer having a diameter smaller than that of the core material 2 and a viscosity of 10 4 10 in the temperature range of poise or more 4 It is a composite of child particles 3 with a viscosity of less than poise, and is in a hammered state where the child particles 3 are hammered into the surface of the core material 2 so as to deform the surface of the core material 2, or in an attached state where the child particles 3 are deformed onto the surface of the core material 2 and the child particles 3 are connected to each other and adhere to each other in a film-like manner.

Description

[Technical Field]

[0001] The present disclosure provides: Method for manufacturing porous structure Regarding. [Background technology]

[0002] Conventionally, wicks with continuous voids that exhibit capillary action have been used on the inner surfaces of heat pipes and vapor chambers to improve the evaporation efficiency of liquid refrigerants. One possible technique for creating such wicks is to utilize the production technology of low-temperature co-fired ceramics (LTCC) substrates (see, for example, Patent Documents 1 and 2). This technique involves dissolving an organic binder in an organic solvent, dispersing alumina powder and low-melting-point glass powder in a slurry, applying it to a film, and then sintering the alumina powder through a heating process. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2017-227382 [Patent Document 2] Japanese Patent Publication No. 2022-70816 Summary of the Invention [Problem to be solved by the invention]

[0004] However, when the techniques of Patent Documents 1 and 2 are adopted, it is necessary to slowly dry the organic solvent at a temperature of, for example, around 100°C where bumping does not occur. Furthermore, in the above techniques, after the organic solvent has dried, a debindering process is required in which the organic binder is slowly burned off to prevent film peeling due to the blow-through of decomposition gases of the organic binder. Furthermore, in the above techniques, it is necessary to lower the viscosity of the glass by heating at a temperature sufficiently higher than the softening point of the glass, so that the glass can be wetted and spread on the surface of the plate material and the surface of the alumina powder. 5 Poise ~10 4It is essential to maintain the temperature at which the solution becomes poise for about 10 minutes.

[0005] For the reasons described above, it is extremely difficult to produce a porous member in a shorter time using the techniques of Patent Documents 1 and 2.

[0006] The present disclosure has been made to solve such problems, and its purpose is to A method for producing porous structures that can be created in a short time The purpose is to provide [Means for solving the problem]

[0010] The method for producing a porous structure according to the present disclosure further comprises the steps of: forming a core material; and forming a porous material having a diameter smaller than that of the core material and a viscosity of the core material of 10 4 10 in the temperature range of poise or more 4 and child particles with a viscosity of less than poise. a hammered state in which the child particles are hammered into the surface of the core material so as to deform the surface of the core material, or an attached state in which the child particles are deformed onto the surface of the core material and are connected to each other to adhere to the surface of the core material in the form of a film, The method comprises a compounding step of compounding to form a large number of compound particles, a spraying step of spraying the large number of compound particles formed in the compounding step onto an adherend, and a heating step of heating the large number of compound particles sprayed onto the adherend in the spraying step so that they are in the temperature range. [Effects of the Invention]

[0011] According to the present disclosure, A method for producing porous structures that can be created in a short time can be provided. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a perspective view showing a heat insulating panel manufactured by a method for manufacturing a porous structure according to an embodiment of the present invention. [Figure 2] 1 is a cross-sectional view showing a heat insulating panel manufactured by a method for manufacturing a porous structure according to an embodiment of the present invention. [Figure 3] FIG. 10 is a cross-sectional view showing another example of a heat insulating panel. [Figure 4] 1A and 1B are enlarged views showing composite particles according to the present disclosure, where (a) shows a first example and (b) shows a second example. [Figure 5]FIG. 5 is a schematic diagram showing a porous structure including a wick using the composite particles shown in FIG. [Figure 6] FIG. 6 is a partially enlarged view of the porous structure shown in FIG. [Figure 7] 1A to 1C are process diagrams showing a method for manufacturing a porous structure. [Figure 8] FIG. 1 is a diagram illustrating an example of a stirring device for producing composite particles. [Figure 9] FIG. 2 is a diagram illustrating an example of a spraying device. [Figure 10] FIG. 10 is a configuration diagram showing a sprinkling device according to a first modified example. [Figure 11] FIG. 10 is a configuration diagram showing a spraying device according to a second modified example. [Figure 12] FIG. 10 is a configuration diagram showing a spraying device according to a third modified example. DETAILED DESCRIPTION OF THE INVENTION

[0013] The present disclosure will be described below in accordance with preferred embodiments. Note that the present disclosure is not limited to the embodiments shown below and can be modified as appropriate without departing from the spirit of the present disclosure. In addition, in the embodiments shown below, some configurations are omitted from illustration and description, but it goes without saying that publicly known or well-known technologies are applied as appropriate to the details of the omitted technologies within the scope of the content described below.

[0014] Figures 1 and 2 are structural diagrams showing a heat insulating panel manufactured by the method for manufacturing a porous structure according to this embodiment, with Figure 1 showing a perspective view and Figure 2 showing a cross-sectional view. The heat insulating panel IP shown in Figures 1 and 2 is configured to include two air conditioning panels 10, a heat insulator 20, and a flow path 30.

[0015] The air conditioning panel 10 is composed of a hollow body formed by processing two plates 11 to form an internal space IS and welding the edges 12. The internal space IS is, for example, evacuated to a reduced pressure. The air conditioning panel 10 is a large structure with a long side of at least 60 cm. Each of the two plates 11 is composed of a thickness of 0.8 mm or less, making the air conditioning panel 10 lightweight.

[0016] As shown in FIGS. 1 and 2, this air-conditioning panel 10 has numerous protrusions 13 formed on both plates 11. The numerous protrusions 13 are formed facing each other on the two plates 11, with the tops of the protrusions 13 in contact with each other. As a result, the two plates 11 are spaced apart in the internal space IS by the height of two protrusions 13. Furthermore, by having the tops of the protrusions 13 in contact with each other, the air-conditioning panel 10, whose internal space IS is evacuated, is more resistant to external pressure. Note that although 32 protrusions 13 are shown in FIGS. 1 and 2, in reality, many more protrusions 13 will be formed because the plates 11 of the air-conditioning panel 10 are thin and large. Specifically, in an air-conditioning panel 10 having a width of 930 mm and a length of 2000 mm, each plate 11 may have, for example, several thousand protrusions 13.

[0017] In this embodiment, the air conditioning panel 10 has a large number of protrusions 13 formed on both of the two plate materials 11, but this is not limited to this, and a large number of protrusions 13 may be formed on only one of the plate materials 11, and the other plate material 11 may be a flat plate.

[0018] A refrigerant flows through these two air conditioning panels 10 via two flow paths 30. The two air conditioning panels 10 are configured so that heat from one air conditioning panel 10 can be dissipated from the other air conditioning panel 10 through the flow of the refrigerant. A heat insulator 20 is provided between the two air conditioning panels 10 to ensure thermal insulation. Therefore, the heat insulator 20 prevents heat from the other side from flowing through to one side of the heat-insulating panel IP, and allows heat from one side to flow through to the other side through the refrigerant circulation.

[0019] When such heat transfer is performed, one of the two air conditioning panels 10 functions as an evaporator E, and the other functions as a condenser C. More specifically, heat from one side causes the liquid refrigerant to evaporate in the evaporator E. As a result, the space S1 side facing the air conditioning panel 10 on one side is cooled by losing heat of evaporation. Meanwhile, the evaporated refrigerant, that is, the vapor refrigerant, reaches the condenser C through the first flow path 31. In the condenser C, the vapor refrigerant is liquefied by heat from the space S2 side facing the other air conditioning panel 10, becoming a liquid refrigerant. The condensation heat generated when the vapor refrigerant liquefies is discarded to the space S2 side. The liquefied liquid refrigerant also reaches the evaporator E again through the second flow path 32. As described above, the insulation panel IP allows heat from one side to pass through to the other side.

[0020] Here, in order to promote evaporation of the liquid refrigerant, at least the air conditioning panel 10 on the evaporator E side has a wick (porous member) 14 formed on at least one plate 11 (the plate 11 on the far side from the condenser C). The wick 14 is made up of a large number of particles and has continuous voids, so that it draws up and holds the liquid refrigerant stored in the lower part of the evaporator E by capillary action. This wick 14 expands the evaporation area of ​​the evaporator E in the height direction, allowing for efficient evaporation in the height direction.

[0021] The wick 14 and the plate 11 to which the wick 14 is bonded form a porous structure.

[0022] FIG. 3 is a cross-sectional view showing another example of the heat insulating panel IP according to this embodiment. The heat insulating panel IP may be formed by connecting the panels shown in FIGS. 1 and 2 to form a structure that is long in one direction, for example. The air conditioning panel 10 must be divided into sections of a predetermined size to allow refrigerant circulation. Therefore, in order to manufacture a long heat insulating panel IP, the air conditioning panel 10 must be divided into sections of a certain size and welded together. These welded sections are called compartment forming portions 15. By dividing the heat insulating panel IP into sections of a certain size using the compartment forming portions 15, the heat insulating panel IP can be formed into a structure that is long in one direction while still allowing refrigerant circulation. The compartment forming portions 15 are also formed in the heat insulating panel IP shown in FIGS. 1 and 2.

[0023] The wick 14 used in the air conditioning panel 10 takes a long time to manufacture. In particular, if the air conditioning panel 10 is large, the manufacturing time is extremely long. In addition, if a long sheet material is wound around an uncoiler and then unwound at a certain speed, a very large facility is required to manufacture the wick 14.

[0024] These points will be explained below. First, as mentioned above, there are various techniques for creating the wick 14. For example, when the techniques of Patent Documents 1 and 2 are used, it takes at least about one hour for heating, and when the plate material is fed at 5 m / min, a heating facility of 300 m is required, and even when the plate material is fed at 1 m / min, a heating facility of 60 m is required.

[0025] Another method for creating the wick 14 is to groove a plate or the like. When forming a large-area wick by groove processing, it is necessary to provide grooves with a width of two digit microns and a depth of at least 100 μm at intervals of at most 0.1 mm, which requires laser processing. However, when forming a wick with a size of 1 m square by laser processing, the total length of the grooves can be as much as 10,000 m, and it is difficult to form a wick with a size of 5 m. 2If a wick is to be formed while feeding out a plate material at a speed of 1 / min, 70 laser devices would be required at a scanning speed of 12 m / sec. For this reason, it is not realistic to form a large-area wick 14 by groove processing.

[0026] Alternatively, the wick 14 may be formed by creating a wire mesh with an opening of about two digit microns and attaching the wire mesh to a plate material. However, the manufacturing of the wire mesh itself can only be done at a low speed. For example, when creating a wire mesh with an opening of 20 μm and a wire density of about 700 strands per inch, even the highest class loom can only produce a wire mesh of 1 m 2 It takes about 7 minutes to reach the 5m 2 To match the sheet material payout speed of 1 / min, 35 of the above looms would be required, which is not realistic. In particular, since the thickness of wire mesh with such openings is only 30-40 μm, multiple sheets would be required to achieve the appropriate wick thickness, making it even more unrealistic.

[0027] Furthermore, when forming a wick 14 using a porous material, as in Patent Documents 1 and 2, it is also possible to apply powder to a plate material using arc spraying or plasma spraying. However, these methods involve spraying the powder onto the plate material at high temperature and high speed, which generally results in a porosity of 10% or less and reduced wick performance. Furthermore, particularly when the thickness of the plate material 11 is 0.8 mm or less, significant distortion occurs in the plate. Therefore, even if an attempt is made to increase the porosity and suppress distortion by slowing down the powder spraying speed, this would result in a decrease in the adhesion strength of the wick to the plate material, which would be problematic for the product.

[0028] To address the above-mentioned issues, the present disclosure uses composite particles described below to manufacture the wick 14. This shortens the manufacturing time, solves the equipment issues, and enables manufacturing on continuously supplied plate materials, etc.

[0029] 4A and 4B are enlarged views showing composite particles according to the present disclosure, with (a) showing a first example and (b) showing a second example. First, as shown in FIGS. 4A and 4B, composite particle 1 comprises core material 2 and child particles 3, which are composited together. Note that while core material 2 is depicted as a sphere in FIG. 4, it does not need to be strictly spherical, and may be shaped like a cube or an angular sphere. The same applies to child particles 3 in FIG. 4A.

[0030] First, the core material 2 is a particle having a larger diameter than the child particles 3. The child particles 3 are particles having a smaller diameter than the core material 2. In the composite particle 1, one core material 2 is composited with many child particles 3.

[0031] For example, as shown in Figure 4(a), composite particle 1 has a spherical surface of core material 2 that is deformed, allowing child particles 3 to enter the deformed portion. That is, composite particle 1 shown in Figure 4(a) is formed by hammering child particles 3 into the surface of core material 2 during the manufacturing process, creating a hammered state. By hammering child particles 3 into the surface in this way, the child particles 3 do not easily come off core material 2, and composite particle 1 is maintained in a composite state.

[0032] Furthermore, as shown in FIG. 4(b), the composite particle 1 is not limited to being hammered into the core material 2, but may also be composited by the child particles 3 deforming and connecting with each other to form a film-like adhesion. Here, if only one child particle 3 is deformed and attached, there is a possibility that the child particle 3 will subsequently detach. However, by connecting the deformed child particles 3 to form a film-like state, the child particles 3 will not easily detach from the core material 2, and the composite particle 1 will be maintained in a composite state. Note that the film-like state referred to here does not necessarily need to completely encase the core material 2, but may be one that maintains a predetermined adhesive force.

[0033] Here, the core material 2 and the child particles 3 are made of different materials. 4Poise or more (preferably 10 5 Poise or more, more preferably 10 6 In the temperature range where the viscosity is 10 poise or more, 4 Less than poise (preferably 10 3 The core material 2 is made up of soda-lime glass beads, and the child particles 3 are made of borosilicate or bismuth low-melting glass. However, the core material 2 and the child particles 3 are not limited to this combination.

[0034] Here, the core material 2 has a viscosity of 10 9 It is preferable that the core material 2 and the child particles 3 are made of a material with a thermal expansion coefficient of poise or less. This allows the core material 2 and the child particles 3 to be firmly bonded by mutual diffusion during heating, as described below. In addition, a transition layer can be formed between the two to prevent breakage due to the difference in thermal expansion coefficient between the two.

[0035] Furthermore, when the average particle size of the core material 2 is 50 μm, the average particle size of the child particles 3 may be 1 to 2 μm, or may be approximately 5 μm. More specifically, compounding is facilitated when the diameter of the child particles 3 is 1 / 20 or less of the diameter of the core material 2. Furthermore, when the child particles 3 are harder than the core material 2 and are hammered together as shown in FIG. 4( a), the particle size should be just right for a single layer of child particles 3 to be evenly adhered to the surface of the core material 2. For example, when the volume of the child particles 3 acting as a binder is approximately 10% of the volume of the core material 2, a diameter of approximately 1.5 μm is appropriate for a core material 2 having a diameter of 50 μm. On the other hand, when the child particles 3 are softer than the core material 2 and adhere in the form of a film, the diameter of the child particles 3 may be approximately 5 μm.

[0036] 5 is a schematic diagram showing a porous structure 100 including a wick 14 using the composite particles 1 shown in FIG. 4. As shown in FIG. 5, the wick 14 is made from a large number of composite particles 1. The wick 14 has a shell 4 formed by melting and then solidifying child particles 3 (see FIG. 4) of a large number of composite particles 1 in a bonded state. For this reason, the shell 4, like the child particles 3, has a viscosity of 10 4 In the temperature range where the viscosity is 10 poise or more, 4 The wick 14 is made up of particles having a viscosity of less than poise. The wick 14 has a structure with continuous voids, which is achieved by covering the core material 2 with the shells 4 and joining the shells 4 together. Such a wick 14 can be manufactured by heating a large number of composite particles 1, for example, in the temperature range described above.

[0037] FIG. 6 is a partially enlarged view of the porous structure 100 shown in FIG. 5. The wick 14 shown in FIG. 5 includes a pigment (infrared absorbing material) 5. The pigment 5 has a higher infrared absorptivity than the core material 2 and the shell 4. In the example shown in FIG. 6, the pigment 5 is contained in the core material 2. Note that the pigment 5 may also be contained in the shell 4. The pigment 5 can be contained in the core material 2 or the shell 4 by melting and mixing the pigment 5 as one of the glass components of the core material 2 or the child particles 3 together with other glass components in a crucible.

[0038] Furthermore, the pigment 5 is not limited to being contained in the core material 2, but may also be compounded. In this case, the pigment 5 can be compounded with the core material 2 or the shell 4 by compounding the pigment 5 simultaneously with or after compounding the core material 2 with the child particles 3. However, compounding of the pigment 5 is not limited to this, and the pigment 5 may be compounded with the core material 2 or the child particles 3 first, and then compounded with the remaining particles 2 and 3. Here, examples of pigments include tricobalt tetroxide, copper oxide, chromium oxide, iron oxide, manganese oxide, tin oxide, and titanium oxide. n O (2n-1) Metal oxide pigments such as (n is a natural number) are particularly preferred because the composite particles 1, which are glass components, are metal oxides and have good compatibility.

[0039] Referring again to Figure 5, the porous structure 100 has a connecting layer 7 on the surface of the adherend 6. The connecting layer 7 is a layer for more firmly attaching the wick 14 to the adherend 6. The connecting layer 7 has a temperature of 10 4 The composite particles 1 are formed from a material with a viscosity of less than poise. Here, the composite particles 1 are firmly bonded together by the melting of their daughter particles 3, similar to double-sided gluing. On the other hand, the composite particles 1 and the adherend 6 are only provided with daughter particles 3, so there is a risk that the bonding strength will be weak due to a single-sided gluing state. Therefore, by providing a connecting layer 7 on the adherend 6 as well, the wick 14 can be firmly bonded to the adherend 6, similar to a double-sided gluing state.

[0040] In particular, when the adherend 6 is stainless steel, the glass material of the composite particles 1 has poor wettability and is repelled from the stainless steel, or even if the wettability is poor, the adhesion is poor and the wick 14 made from the composite particles 1 is easily peeled off after cooling. Furthermore, the flexibility of the wick 14 made from the composite particles 1 is insufficient, and it is often unable to follow the bending of the stainless steel, causing it to crack and peel off. For this reason, it is more preferable to provide the connection layer 7 when the adherend 6 is made of stainless steel.

[0041] Here, the connecting layer 7 is preferably made of the same material as the shell 4. This makes it easier for the shell 4 and the connecting layer 7 to fuse together, and a stronger connection can be expected.

[0042] The connecting layer 7 is not limited to the above. For example, glass frits with special compositions, such as enamel glazes and glass lining glazes, have been researched and formulated for stainless steel applications. Among these, those for single-coating combine the adhesion to stainless steel required for an undercoat glaze with the water resistance required for a topcoat glaze. Therefore, they may be used for the connecting layer 7. In this case, it is preferable that the connecting layer 7 has a thermal expansion coefficient suitable for a stainless steel glaze, and that the shell 4 has a thermal expansion coefficient intermediate between that of the core material 2 and that of the connecting layer 7.

[0043] Furthermore, it is known that the inclusion of boron oxide in stainless steel enamel improves wettability to stainless steel, and the inclusion of diphosphorus pentoxide or vanadium pentoxide corrodes the stainless steel surface, improving adhesion. It is also known that the addition of lanthanides such as samarium and erbium and oxides of metals such as cobalt and nickel to the connection layer 7 forms whiskers at the interface, dramatically improving adhesion. Therefore, these technologies may be utilized for the connection layer 7.

[0044] Next, a method for manufacturing the porous structure 100 according to the present disclosure will be described. Fig. 7 is a process chart showing a method for manufacturing the porous structure 100. The method for manufacturing the porous structure 100 is roughly composed of four steps: a composite step (S1), an adhesion step (S2), a spraying step (S3), and a heating step (S4). These steps will be described in detail below.

[0045] The composite step (S1) is a step of producing composite particles 1 by combining a core material 2 with a child particle 3. Fig. 8 is a structural diagram showing an example of a stirring device for producing composite particles 1. The composite particles 1 shown in Fig. 4 can be produced by dry stirring using a stirring device 200 shown in Fig. 8.

[0046] 8 includes a roughly cylindrical housing 210 and a stirring blade 220 that rotates inside the housing 210. The core material 2 and the child particles 3 are housed in the housing 210 and dry-stirred for a predetermined period of time to be compounded.

[0047] Here, the distance L1 between the side surface 211 of the housing 210 and the agitating blade 220 is, for example, within 2 mm. In addition, the distance L2 between the top surface 212 of the housing 210 and the agitating blade 220 is also within 2 mm. In this way, when the core material 2 and the child particles 3 pass through the narrow section NS where the distance between the side surface 211 and the top surface 212 of the housing 210 and the agitating blade 220 becomes narrow, they are pressed firmly against each other. This produces the composite particle 1 in the hammered or adhered state shown in FIG. 4.

[0048] The stirring device 200 may be one in which the narrow section NS is formed only between the side surface 211 and the stirring blade 220, or one in which the narrow section NS is formed only between the upper surface 212 and the stirring blade 220.

[0049] Here, it is preferable that the areas on the side surface 211 and the upper surface 212 that form the narrow section NS are large when the stirring blade 220 is rotating. This is because the dry stirring time can be shortened. When producing the composite particle 1, it is necessary to optimize the above-mentioned areas and stirring time, and the composite particle 1 can be obtained by optimizing these.

[0050] The stirring device 200 is not limited to the one shown in Figure 8, and the stirring device 200 shown in Figure 8 may be configured in multiple stages, one above the other, so that the core material 2 and the child particles 3 are introduced from the top and the composite particles 1 are obtained when they reach the bottom.

[0051] Referring to FIG. 7, after the compounding step (S1), an adhering step (S2) is carried out. The adhering step (S2) is a step of adhering powder particles to an adherend 6. The powder particles to be adhered are made of a material having a viscosity of 10 4 The viscosity of core material 2 is less than 10 poise. 4 In the temperature range where the viscosity is 10 poise or more, 4 The connection layer 7 is formed by this process.

[0052] The adhesion step (S2) does not have to be performed after the compounding step (S1) as long as it is performed before the spraying step (S3) described below, and may be performed before the compounding step (S1).

[0053] Next, the spraying step (S3) is performed. The spraying step (S3) is a step of spraying a large number of composite particles 1 produced in the composite step (S1) onto the adherend 6. Here, it is preferable to spray a large number of composite particles 1 uniformly onto the adherend 6 in the spraying step (S3) so that the wick 14 is formed with a uniform thickness. It is also preferable to spray a large number of powder particles uniformly onto the adherend 6 in the adhesion step (S2). In this case, if the adherend 6 is a flat plate, it is possible to achieve a constant film thickness by sweeping the powder particles and composite particles 1 with a blade member after the adhesion of the large number of powder particles and after the dispersion of the large number of composite particles 1.

[0054] On the other hand, when the adherend 6 is not a flat plate, such as the embossed plate 11 shown in Fig. 1, it is not possible to form a uniform film thickness using a blade member. Therefore, it is preferable to use a spraying device shown in Fig. 9.

[0055] Fig. 9 is a structural diagram showing an example of a spraying device. The spraying device 300 shown in Fig. 9 sprays composite particles 1 onto the adherend 6, which is a plate material continuously supplied from a coiled plate material. Note that the following description will be given taking the spraying device 300 that sprays composite particles 1 as an example, but it may also be used when adhering powder particles. The spraying device 300 may also be used on a stationary adherend 6.

[0056] 9 includes a container 310, a spraying section 320, and an electric field application section (electric field application means) 330. This spraying device 300 charges the composite particles 1 while charging the adherend 6 with an electric charge opposite to that of the composite particles 1, thereby spraying the composite particles 1 so that they collide with the adherend 6 by electrostatic force, and also preventing scattering after spraying by utilizing intermolecular forces, etc.

[0057] The container 310 is provided at a position above the adherend 6 and is made of stainless steel. The composite particles 1 are stored in the container 310. The container 310 is preferably made of stainless steel from the viewpoints of ease of manufacturing, abrasion resistance, and whether it can tolerate abrasion powder mixed in. Furthermore, since the container 310 is made of stainless steel, when the composite particles 1 made of glass material are rubbed, the container 310 becomes positively charged, the same charge as the spraying unit 320, as will be described later.

[0058] The spraying unit 320 sprays the composite particles 1 in the container 310 onto the adherend 6, and includes a rotor 321 and a blade member (specific member) 322. Here, the container 310 includes an inlet (not shown) for putting the composite particles 1 into the container 310, and a spray-side opening 311 that serves as an opening for spraying the composite particles 1 onto the adherend 6. The rotor 321 is provided so as to almost completely cover the spray-side opening 311, and is made of, for example, stainless steel. Furthermore, the rotor 321 is knurled, dimpled, or the like, to form numerous very small depressions.

[0059] The blade member 322 is provided near the lower end of the spray-side opening 311 in a state of contact with the rotor 321 or in a state of close proximity with a minute gap corresponding to the diameter of the composite particles 1. The blade member 322 adheres the composite particles 1 to the rotor 321 with a uniform thickness by utilizing the contact with the rotor 321 or the minute gap. The blade member 322 has a base material 322a and a surface portion 322b, and the surface portion 322b is made of at least one of fluororesin, silicone resin, polyvinyl chloride, and materials containing any of these as their main components.

[0060] Furthermore, the rotor 321 rotates near the lower end of the spray-side opening 311 in a direction from the inside of the container 310 to the outside of the spray-side opening 311. That is, in the example shown in FIG. 9, the rotor 321 rotates counterclockwise. Because the rotor 321 rotates in this manner, a large number of composite particles 1 are attached by the blade member 322, and when the rotor 321 separates from a friction point (hereinafter referred to as a friction portion FP) that is in contact with or close to the blade member 322, the large number of composite particles 1 are sprayed onto the adherend 6. In particular, the composite particles 1 are sprayed onto the adherend 6 in a state in which they are charged by friction between the container 310, the rotor 321, and the blade member 322. In particular, because the container 310 and the rotor 321 are made of stainless steel and the blade member 322 is made of the above-mentioned material, the composite particles 1, which are glass, are positively charged.

[0061] The electric field application unit 330 applies a DC electric field in which the adherend 6 is negative and the rotor 321 and blade member 322 (particularly the substrate 322a) are positive. As described above, the composite particles 1 are positively charged. Therefore, if the adherend 6 is negative, the composite particles 1 are dispersed as if attracted to the adherend 6. Furthermore, by rotating the rotor 321 and dispersing the composite particles 1 while utilizing contact or proximity with the blade member 322, it is possible to achieve uniform dispersion according to the rotation speed of the rotor 321. Note that if the composite particles 1 are dispersed by the rotation of the rotor 321 when the composite particles 1 are not charged, phenomena such as the composite particles 1 flying around can occur, making it difficult to achieve a uniform film thickness.

[0062] Furthermore, in the spraying device 300, if the rotor 321 is knurled or dimpled to a depth according to the particle size of the composite particles 1, and the blade member 322 is used to appropriately press the composite particles 1 against the rotor 321, it is possible to prevent the composite particles 1 from falling off the rotor 321 when the rotor 321 stops. In particular, if the composite particles 1 are appropriately compounded in the compounding step (S1), the core material 2 and the child particles 3 do not separate, and it is possible to prevent the two from separating and only the child particles 3 from falling off.

[0063] Here, the composite particle 1 is not positively charged by the electric field application unit 330, but is positively charged by friction. The electric field application unit 330 eliminates the saturation state of the rotor 321 and the blade member 322 caused by this friction. That is, the rotor 321 and the blade member 322 positively charge the composite particle 1 due to friction with the composite particle 1, but when not grounded, they themselves become negatively charged. Therefore, unless the negative charge accumulated in the rotor 321 and the blade member 322 is released, the blade member 322 will become negatively saturated, and the composite particle 1 will no longer be able to be positively charged by friction. Therefore, the electric field application unit 330 applies a positive DC electric field to the rotor 321 and the blade member 322 to prevent them from becoming negatively saturated.

[0064] Here, a technique for peeling powder from a rotating body using an AC electric field has been proposed in JP 9-1039 A. This technique uses electrostatic repulsion to separate powder from a rotating body, and is different from the technique of the above-mentioned spraying device 300, which uses a DC electric field to cause powder to fly and collide with the adherend 6.

[0065] The spraying device 300 further includes a brush member (second specific member) 340. The brush member 340 is provided outside the container 310 and in contact with the rotor 321 in the rotational direction of the rotor 321 relative to the blade member 322. Like the blade member 322, the brush member 340 is made of at least one of fluororesin, silicone resin, polyvinyl chloride, and materials containing these as their main components. The brush member 340 is, for example, a brush roll with a rotation mechanism, and rotates in the same direction as the rotor 321 (counterclockwise in the state shown in FIG. 9). This allows the brush member 340 to scrape off any remaining composite particles 1 on the rotor 321 and to positively triboelectrically charge the composite particles 1 again. This can contribute to eliminating a situation in which composite particles 1 remain stuck to the rotor 321 at a certain location on the rotor 321, preventing the composite particles 1 from being sprayed uniformly at that location on the adherend 6. A positive DC electric field is also applied to the brush member 340 by the electric field application unit 330, thereby preventing saturation.

[0066] More specifically, the spraying device 300 is configured such that the electric field strength applied by the electric field application unit 330 is 1 kV / cm or more and 5 kV / cm or less, and the distance between the friction unit FP (more precisely, the position slightly toward the rotation direction of the rotor 321 from the friction unit FP, where spraying of the numerous composite particles 1 begins) and the adherend 6 is 100 mm or less. Therefore, for example, if the distance is 40 mm, the voltage of the electric field application unit 330 should be set to 10 kV or the like. This is because a sufficient electrostatic effect cannot be obtained if the electric field strength is less than 1 kV / cm, and electrostatic repulsion and sparks are likely to occur if the electric field strength exceeds 5 kV / cm.

[0067] Furthermore, it is preferable that the distance between the friction portion FP and the adherend 6 is within 20 mm (for example, a distance of 20 mm and a voltage of 5 kV). This allows the composite particles 1 to be dispersed within 10 mm of the intersection with the perpendicular line drawn from the friction portion FP to the adherend 6. Also, because the composite particles 1 can be dispersed within 10 mm of the intersection, it is possible to prevent the composite particles 1 from being dispersed in the intended welding area on the outer periphery of the adherend 6, for example, without using masking. Furthermore, because the composite particles 1 can be dispersed within 10 mm of the intersection, a recovery device for recovering composite particles 1 scattered in unintended locations is not required.

[0068] In the example shown in FIG. 9, the adherend 6 is continuously supplied. Such adherend 6 comes into contact with a device, such as an uncoiler that unwinds rolled material, and would be grounded if a positive electric field were applied. Therefore, the spraying device 300 shown in FIG. 9 applies a negative DC electric field to the adherend 6 and a positive DC electric field to the rotor 321, blade member 322, and brush member 340. It uses a positive-supply type high-voltage power supply in which the box is electrically connected to the negative terminal. However, if the adherend 6 is not continuously supplied, a negative-supply type high-voltage power supply in which the box is electrically connected to the positive terminal may be used, and the positive terminal and blade may be earthed. Alternatively, a positive DC electric field may be applied to the adherend 6, and a negative DC electric field may be applied to the rotor 321, blade member 322, and brush member 340. In this case, the composite particles 1 will be negatively charged due to friction, so the materials used for each component must be optimized.

[0069] 9, a positive DC electric field is applied to both the rotor 321 and the blade member 322. However, since the rotor 321 and the blade member 322 are in close proximity or in contact with each other, a positive DC electric field may be applied to only one of them. This is because saturation can be eliminated not only when they are in contact but also when they are in close proximity.

[0070] Fig. 10 is a structural diagram showing a spraying device according to a first modified example. As shown in Fig. 10, in a spraying device 300a according to the first modified example, the friction part FP is located approximately to the side of the rotor 321. In this case, the rotor 321 approaches the adherend 6, and if the position of the rotor 321 closest to the adherend 6 is set to the bottom dead center LD, discharge occurs from the bottom dead center LD to the adherend 6. Furthermore, the composite particles 1 that have come into contact with the adherend 6 and become negatively charged are attracted by the rotor 321 to which a positive DC electric field is applied, and the composite particles 1 may be scattered.

[0071] Therefore, as in the spraying device 300 shown in Fig. 9, it is preferable that the friction part FP is within a range of 45° (symbol θ) from the bottom dead center LD of the rotor 321. This makes it easier to suppress the amount of downward protrusion of the rotor 321 from the friction part FP and to suppress discharge and scattering of the composite particles 1. Note that if discharge and scattering can be suppressed by another means or if discharge and scattering can be tolerated to some extent, a spraying device 300a shown in Fig. 10 may be used.

[0072] Fig. 11 is a structural diagram showing a spraying device according to a second modified example. In the spraying device 300b shown in Fig. 11, the surface portion 322b of the blade member 322 is formed from a long film material F. The long film material F is provided with a payout portion 351 and a take-up portion 352 on both ends, making it possible to change the friction position between the film material F and the rotor 321. This contributes to preventing a situation in which the blade member 322 is worn down due to friction and more than the intended amount of composite particles 1 is sprayed. In addition, the spraying device 300b shown in Fig. 11 is formed from a brush member 340 having brush-like bristles.

[0073] Fig. 12 is a structural diagram showing a spraying device according to a third modified example. The spraying device 400 shown in Fig. 12 comprises a container 410, a spraying section 420, and an electric field application section (electric field application means) 430. The container 410 is similar to that shown in Figs. 9 to 11, but has a spray-side opening 411 at the bottom.

[0074] The spraying unit 420 includes a rotor 421 and a mesh (specific member) 422. A brush roll is used as the rotor 421, rather than an agitator, squeegee, or other reciprocating device. At least the brush tip of the rotor 421, which comes into contact with the composite particle 1, is made of at least one of fluororesin, silicone resin, polyvinyl chloride, and materials containing these as main components.

[0075] The mesh 422 is a member provided to close the dispersing side opening 411. The mesh 422 has an opening size greater than 100% and less than 150% of the average particle size of the composite particles 1, and more preferably greater than 100% and less than 130%. The mesh 422 with such opening size is configured so that the composite particles 1 do not fall off under their own weight. The rotor 421 is provided to sweep the mesh 422. The mesh 422 is made of stainless steel.

[0076] This spraying unit 420 can spray an amount of composite particles 1 onto the adherend 6 according to the rotation speed of the rotor 421 by causing the composite particles 1 to pass through the openings of the mesh 422 due to the rotation of the rotor 421.

[0077] The electric field application unit 430 applies a negative DC electric field to the adherend 6 and a positive DC electric field to the mesh 422. Here, the rotor 421 and the mesh 422 positively charge the composite particle 1 due to friction with the composite particle 1, while being negatively charged themselves. Therefore, the rotor 421 and the mesh 422 will become negatively saturated unless the accumulated negative charge is released, and the composite particle 1 will no longer be positively charged due to friction. Therefore, the electric field application unit 430 applies a positive DC electric field to the mesh 422 to prevent the rotor 421 and the mesh 422 from becoming negatively saturated. Note that the rotor 421 is configured to sweep the mesh 422, so that the rotor 421 is also prevented from becoming saturated. Alternatively, the electric field application unit 430 may apply a positive DC electric field to the rotor 421.

[0078] In the spraying step (S3) shown in FIG. 7, the spraying device 300, 300a, 300b, or 400 described above uniformly sprays the composite particles 1 onto the adherend 6. These spraying devices 300, 300a, 300b, or 400 have the advantage of being more effective at achieving a consistent film thickness than air spraying methods, including corona- and tribo-electrostatic powder coating. The spraying devices 300, 300a, 300b, or 400 are not limited to those described above, and may be air spraying methods or other methods as long as there are no problems with film thickness accuracy. Furthermore, the spraying device 400 may be a sieve type different from that shown in FIG. 12, in which composite particles 1 are dropped by an agitator reciprocating through a mesh 422 and then received by a spraying roller before being dropped onto the adherend 6.

[0079] As shown in Fig. 7, the heating step (S4) is carried out after the spraying step (S3). The heating step (S4) is a step of heating the numerous composite particles 1 sprayed onto the adherend 6 in the spraying step (S3) so that the composite particles 1 reach the above-mentioned temperature range. In this step, the adherend 6 is continuously transported at a speed of 1 m per minute or more.

[0080] The heating step (S4) can utilize a high-speed temperature increase process. This is because no organic solvents or organic binders are used in the heating target, there is no risk of defects due to vaporized components blowing through, and there are no components that take a long time to thermally decompose. Therefore, the heating step (S4) can be completed in a short time. In particular, as shown in Figures 4(a) and 4(b), since the composite particle 1 has child particles 3 surrounding the core material 2, it does not take much time for the child particles 3 to dissolve, move, and integrate. Therefore, for these reasons as well, the heating step (S4) can be completed in a short time.

[0081] The heating step (S4) is preferably performed without contact while the adherend 6 is suspended in mid-air. After the spraying step (S3), the composite particles 1 and powder particles are lightly adhered. Therefore, by performing the heating without contact while suspended in mid-air, vibrations due to transportation can be prevented from being applied until the wick 14 is completed after the composite particles 1 are heated and cooled.

[0082] In the heating step (S4), electromagnetic wave heating and induction heating are considered as high-temperature heating processes. This is because these heating methods can heat the adherend 6 provided with the composite particles 1, etc., to approximately 700°C within one minute without contact. More specifically, in the case of electromagnetic wave heating, a temperature rise of 100°C / sec is possible when a mid-to-near infrared heater is used, and a temperature rise of 1000°C / sec or more is possible when laser heating is used. Furthermore, induction heating can also raise the temperature at 100 to 500°C / sec.

[0083] More specifically, mid- and near-infrared heaters include near-infrared heaters, halogen heaters, and carbon filament heaters. Near-infrared heaters have a tungsten filament that glows at around 2000°C or higher inside a quartz tube filled with inert gas. Halogen heaters have a tungsten filament that glows at around 2000°C or higher inside a quartz tube filled with inert gas, and also contain halogen to achieve the halogen effect. Carbon filament heaters have a carbon filament that glows at around 1000°C inside a quartz tube filled with inert gas.

[0084] Of the light emitted by these filaments, most of the components with wavelengths of 4.5 μm or longer are absorbed by the quartz tube and converted into far-infrared rays, which do not contribute much to high-temperature heating. For example, soda-lime glass and borosilicate glass, which are suitable for the core material 2, have high absorption rates for wavelengths of 2.7 μm or longer and 2.8 μm or longer, respectively, but have low absorption rates for infrared rays with wavelengths shorter than these. In contrast, low-melting-point glass, which is suitable for the child particles 3, absorbs even shorter wavelengths depending on its components, so it is more efficient to heat it with a heater that emits a lot of light with wavelengths between these wavelengths and 4.5 μm.

[0085] It should be noted that the emissivity of a tungsten filament is 20% or less at wavelengths of 2.7 μm or more, which makes it less efficient than the above wavelengths. However, because the filament temperature is high, it is possible to heat the composite particle 1 to a high temperature. Furthermore, the infrared rays that pass through the composite particle 1 contribute to heating the adherend 6, and the infrared rays reflected from the adherend 6 contribute again to heating the composite particle 1.

[0086] Carbon filaments have an emissivity of about 85% at wavelengths of 2.7 μm or greater, allowing for efficient heating. However, because the filament temperature is not particularly high, as the temperature of the composite particles 1, which are the target of heating, increases with heating, the temperature approaches the filament temperature and the efficiency decreases.

[0087] The heating time and other details of the heating step (S4) will be explained. First, the tungsten filament near-infrared heater is 300 kW / m 2 About 150kW / m for carbon filament mid-infrared heaters 2 Generally, heaters with an irradiation density of up to about 180kW / m are used. In the case of laser heating, energy densities 10 times higher can be obtained. As an example, taking into consideration the reliability of overheat prevention control, a relatively low irradiation density is used, for example, for a 0.3mm thick stainless steel plate, with 180kW / m from one side. 2 When a near-infrared heater is applied, a temperature rise rate of approximately 30°C / second can be achieved.

[0088] As an example, if zinc borosilicate alkali-containing glass with a softening point of 540°C is used as the child particles 3, the fluidity is low at 550°C and it takes several minutes for sintering to proceed, but at 600°C it takes about 10 seconds, and at 730°C it takes about 1 second. When heated at a heating rate of 30°C / second, sintering begins about 17 seconds after reaching 540°C, and if the temperature continues to rise, sintering will be fully completed by 24 seconds after reaching 730°C. In this case, if the plate material is heated while being transported at 5 m / min, the heating section will be improved by about 2 m.

[0089] In this heating section, if the core material 2 is soda lime glass, it will finally reach its softening point (when the viscosity reaches 10 9In this case, the core material 2 is not substantially deformed, but mass transfer is active at the micro level. Therefore, the core material 2 and the shell 4 are firmly bonded by mutual diffusion, and a transition layer is generated in which the glass composition changes continuously. Therefore, the thermal expansion coefficient changes continuously within the transition layer, and damage due to the difference in thermal expansion is suppressed.

[0090] In this way, using glass particles with a softening point relatively close to that of the shell 4 as the core material 2 rather than metal particles or high-melting point ceramics such as alumina has the effect of making the bond between the shell 4 and the core material 2 strong through diffusion and of high quality with a transition layer.

[0091] Furthermore, if bismuth oxide glass with a low softening point (e.g., a softening point of 390°C) is used as the child particles 3, the softening point is reached in just over 12 seconds of heating, and sintering is completed after 18 seconds of heating to 560°C. Bismuth oxide glass is characterized by its remarkable fluidity above its softening point. In this case, when heating a plate material while transporting it at 5 m / min, the heating section can be improved by approximately 1.5 m.

[0092] Induction heating generally allows for a higher heating rate than infrared heating. However, there is a risk of overheating, for example, during a sudden stop of the adherend 6 during production, which can damage the adherend 6 and the composite particles 1. When the adherend 6 is a thin plate of a paramagnetic material such as austenitic stainless steel, the induced current has a deep penetration depth, causing the currents on the front and back surfaces to cancel each other out, making solenoid coils unusable and requiring transverse coils. When using ferromagnetic materials such as steel plate or ferritic stainless steel, the penetration depth is shallow at sufficiently high frequencies, making solenoid coils usable even for thin plates. However, when such adherends 6 reach their Curie temperature, they change from ferromagnetic to paramagnetic, causing the induced currents to cancel each other out, making it difficult to further heat them with a solenoid coil. The Curie temperature of iron is approximately 770°C, while that of SUS430, a typical ferritic stainless steel, is approximately 680°C. Therefore, for example, when ferritic stainless steel is used as the adherend 6 and a solenoid coil is used for heating, the adherend 6 will not be heated above 680°C, so overheating can be automatically prevented.

[0093] In this way, the adherend 6 (e.g., ferritic stainless steel) is a ferromagnetic material at room temperature (e.g., 30°C), and has a Curie temperature at which it changes into a paramagnetic material. 4 poise or more core material 2 (e.g. soda lime glass) and 10 4 By using composite particles 1 combined with child particles 3 (e.g., borosilicate enamel for stainless steel) with a viscosity of less than poise and inductively heating them with a solenoid coil, it is possible to create a porous structure 100 in a very short time and within a short heating period, while suppressing problems caused by overheating.

[0094] It should be noted that a heating furnace is not essential in the heating step (S4). When near-infrared heating, mid-infrared heating, laser heating, and induction heating are performed, direct heating is performed using electromagnetic waves, etc., so a furnace body (a box or tunnel with thermally insulated walls) is not required.

[0095] After the heating step (S4) is completed, cooling is carried out, and the production of the porous structure 100 is completed.

[0096] In this way, the composite particle 1 according to the first embodiment is formed by mixing the core material 2 and the core material 2 having a viscosity of 10 4 10 in the temperature range of poise or more 4 and child particles 3 having a viscosity of less than poise. Furthermore, the composite particle 1 is in a hammered state in which the child particles 3 are hammered into the core material 2 so as to deform the surface of the core material 2, or in an attached state in which the child particles 3 are deformed onto the surface of the core material 2 and are connected to each other to form a film. In such a hammered or attached state, the core material 2 and the child particles 3 are integrated without the need for an organic solvent or organic binder. By heating in this state, for example, to the above-mentioned temperature range, the child particles 3 can be bonded to each other to obtain a wick 14. In particular, since no organic solvent or organic binder is required, prolonged heating for drying or decomposition thereof is not required. Therefore, a composite particle 1 can be provided that can produce a wick 14 in a shorter time.

[0097] In addition, the core material 2 has a viscosity of 10 4 Over 10 9 The wick 14 is made of a material with a viscosity of 0.05 poise or less. Therefore, the core material 2 does not become too hard, and when heated in the above temperature range, the core material 2 and the shell 4 (child particles 3) can be easily firmly bonded by mutual diffusion. Furthermore, a transition layer in which the glass component changes continuously is generated between the two, and the thermal expansion coefficient also changes continuously within the transition layer, making it possible to form a wick 14 that is easily prevented from being broken due to differences in thermal expansion coefficients, etc.

[0098] Furthermore, the wick 14 according to the first embodiment includes a pigment 5 that is contained in or compounded with the core material 2 or the shell 4 and has a higher infrared absorption rate than the core material 2 and the shell 4. Therefore, when heating using infrared rays, the wick 14 is efficiently heated through the pigment 5. Therefore, it is possible to provide a wick 14 that can be produced in a short time.

[0099] The porous structure 100 according to the first embodiment is provided on the wick 14 surface of the adherend 6, and is resistant to 10 4The wick 14 is provided with a connecting layer 7 formed of a material with a viscosity of less than poise. Here, since the composite particles 1 each have a shell 4, the composite particles 1 are likely to be firmly bonded to each other by both shells 4 when bonded. Therefore, when the connecting layer 7 is provided, the wick 14 can be more firmly bonded to the adherend 6 by the connecting layer 7 and the shell 4 in the same manner.

[0100] Furthermore, in the method for manufacturing the porous structure 100 according to the first embodiment, the core material 2 and the core material 2 having a diameter smaller than that of the core material 2 and a viscosity of 10 4 10 in the temperature range of poise or more 4 The method includes a composite step (S1) in which a large number of composite particles 1 are produced by compositing the core material 2 with the child particles 3, which have a viscosity of less than poise. This allows the core material 2 and the child particles 3 to be integrated without the need for an organic solvent or organic binder. The child particles 3 can then be bonded together by spraying the composite particles 1 on the adherend 6 and heating them in the above-mentioned temperature range. In particular, this heating does not require a long heating time, as is required for drying the organic solvent or organic binder. This makes it possible to provide a method for producing a porous structure 100 that can be produced in a short time.

[0101] Furthermore, in the heating step (S4), the adherend 6 is continuously supplied at a speed of 1 m per minute or more. Here, since the numerous composite particles 1 are integrated without the need for an organic solvent or organic binder, the wick 14 can be produced by heating for a short period of time, and the heating can be completed even when the adherend 6 is continuously supplied. Therefore, it is possible to provide a method for producing a porous structure 100 that allows the adherend 6 to be continuously supplied in a shorter period of time.

[0102] Furthermore, in the composite process (S1), the core material 2 and the child particles 3 are dry-mixed to form a hammered or adhered state, so that not only no organic solvent or organic binder is required, but also no other liquid components are required, and a manufacturing method for the porous structure 100 that can be produced in a short time can be provided.

[0103] Furthermore, a DC electric field is applied between the spraying devices 300, 300a, 300b, and 400 and the adherend 6, charging the numerous composite particles 1 with an electric charge opposite to that of the adherend 6, and thus the numerous composite particles 1 are sprayed as if attracted to the adherend 6. Furthermore, it is believed that intermolecular forces also act on the numerous electrostatically sprayed composite particles 1 after they collide with the adherend 6, and although they do not fall off when the adherend 6 is turned upside down and lightly shaken after a certain period of time has passed since the electrostatic effect disappeared, they can be attached with such adhesive force that they fall off easily when touched with a finger. Therefore, not only can the numerous composite particles 1 be sprayed efficiently, but the numerous composite particles 1 are less likely to move in subsequent processes, which can contribute to reducing the possibility of differences in the thickness of the wick 14.

[0104] In addition, prior to the spraying step (S3), the above temperature range is 4 The method further includes an adhesion step (S2) of adhering powder particles with a viscosity of less than poise to the adherend 6. Here, since the composite particles 1 each have child particles 3, the composite particles 1 are more firmly bonded together by the bonding of both child particles 3. Therefore, when the adhesion step (S2) is included, the wick 14 can be more firmly bonded to the adherend 6 by the powder particles and the child particles 3 in the same manner.

[0105] Furthermore, the spraying devices 300, 300a, 300b, and 400 according to the present embodiment rotate the rotors 321 and 421 from the stainless steel containers 310 and 410, dispensing powder from the containers 310 and 410 while causing friction and charging the powder, thereby spraying the powder onto the adherend 6. This allows the powder to be sprayed onto the adherend 6 using electrostatic force. When the powder is glass, the blade member 322 and rotor 421, which are the subject of friction, are made of at least one of fluororesin, silicone resin, polyvinyl chloride, and materials containing these as their main components, which have a strong negative charge. When the adherend 6 is a continuously supplied material such as a coil material, the negative side is grounded. In addition, because the blade member 322 and rotor 421 lose positive charge during friction, applying a positive electric field by the electric field application units 330 and 430 prevents the positive charge from being lost and becoming saturated. Therefore, it is possible to provide spraying devices 300, 300a, 300b, and 400 that can spray powder onto adherends 6 that are continuously supplied using electrostatic force without the charge of the member becoming saturated.

[0106] Furthermore, the blade member 322 is disposed in contact with or in close proximity to the rotor 321 within a 45-degree range centered on the bottom dead center LD. Therefore, the powder is dispersed from a position closer to the bottom dead center LD, which is closer to the adherend 6, making it easier to spray the powder at a targeted location on the adherend 6. Furthermore, when a positive electric field is applied to the rotor 321, the positive electric field portion is reduced in the region closer to the adherend 6 than the dispersion position (friction portion FP), making it easier to spray the powder at a targeted location on the adherend 6.

[0107] The brush member 340 is provided on the rotational direction side of the rotor 321, and scrapes off powder adhering to the rotor 321 and frictionally charges it, and a positive DC electric field is applied to the brush member 340. This helps to remove powder adhering to the rotor 321 from the rotor 321, charge it, and scatter it, while also contributing to preventing saturation.

[0108] Furthermore, surface portion 322b of blade member 322 is a long film material F, and the position of the friction portion with the powder can be changed by moving film material F. This contributes to preventing a situation in which surface portion 322b is scraped off by friction and more powder than intended is dispersed.

[0109] The adherend 6 is a ferromagnetic material at room temperature and has a Curie temperature at which it changes to a paramagnetic material. The composite particles 1 have a viscosity of 10 4 Core material 2 with a viscosity of 10 poise or more at its Curie temperature 4 The composite particles 1 are formed by compositing the composite particles 1 with the child particles 3 having a viscosity of less than poise. Furthermore, in the heating step (S4), the numerous composite particles 1 are heated via the adherend 6 by induction heating using a solenoid coil. This makes it difficult for the temperature of the adherend 6 to exceed the Curie point during heating, thereby reducing the possibility of damage to the adherend 6 or the composite particles 1 due to overheating.

[0110] The present disclosure has been described above based on the embodiments, but the present disclosure is not limited to the above embodiments, and modifications may be made within the scope of the spirit of the present disclosure, and publicly known or well-known technologies may be combined to the extent possible.

[0111] For example, although the wick 14 is given above as an example of a porous member, it is not limited to the wick 14 and may be other porous members such as a filter.

[0112] Furthermore, the following is added:

[0113] (Appendix 1) The core material has a viscosity of 10 in the temperature range. 4 Over 10 9 It is made of a material with a resistance of less than poise 2. The composite particle according to claim 1 .

[0114] (Appendix 2) A spraying device that sprays powder onto a continuously supplied adherend, a stainless steel container provided above the adherend; a spraying means for spraying the powder onto the adherend by rotating a rotating body to discharge the powder from the container and causing friction with a specific member to charge the powder; and and an electric field applying means for applying a DC electric field to the adherend as a negative field and to at least one of the specific member and the rotating body as a positive field, the powder is made of a glass material, At least one of the specific member and the rotating body that comes into contact with the powder is made of at least one of fluororesin, silicone resin, polyvinyl chloride, and materials containing these as main components. A spraying device characterized by:

[0115] (Appendix 3) The specific member is a blade member that rubs against the powder, When the bottom dead center is the part of the rotating body that is closest to the adherend, the specific member is disposed in contact with or in close proximity to the rotating body within a 45-degree range centered on the bottom dead center. 3. The spraying device according to claim 2,

[0116] (Appendix 4) a second specific member provided on the rotating body in the rotation direction relative to the specific member, which scrapes off powder adhering to the rotating body and frictionally charges the powder, The second specific member is applied with a positive DC electric field by the electric field application means. 4. The spraying device according to claim 2 or 3,

[0117] (Appendix 5) The specific member is a long film material made of at least one of fluororesin, silicone resin, polyvinyl chloride, and materials containing these as main components, and the film material can be moved to change the position of the friction part with the powder. 5. The spraying device according to claim 2, wherein the spraying device is a spraying device having a nozzle. [Explanation of symbols]

[0118] 1: Composite particles 2: Core material 3: Child particle 4: Shell 5: Pigment (infrared absorbing material) 6: Adherent 7: Connection layer 14: Wick (porous material) 100: Porous structure 200: Stirring device 300,300a,300b,400: Spraying equipment 310,410: Container 321,421: Rotating body 322: Blade member (specific member) 330, 430: Electric field application unit (electric field application means) 340: Brush member (second specific member) 422: Mesh (specific component) F: Film material FP:Friction part LD: Bottom dead center NS: Narrow section S1: Composite process S2: Adhesion process S3: Spraying process S4: Heating process

Claims

1. A core material and a particle having a diameter smaller than that of the core material and a viscosity of the core material of 10 ４ 10 in the temperature range where the temperature is above poise ４ a composite step of forming a large number of composite particles by combining the child particles having a viscosity of less than poise into a state in which the child particles are hammered into the surface of the core material so as to deform the surface of the core material, or by forming the child particles into a state in which the child particles are deformed onto the surface of the core material so as to connect with each other and adhere to each other in a film-like manner; a spraying step of spraying the numerous composite particles produced in the compounding step onto an adherend; a heating step of heating the adherend so that the numerous composite particles scattered on the adherend in the scattering step are in the temperature range; A method for manufacturing a porous structure, comprising:

2. The adherend is a plate material continuously supplied from a rolled plate material wound into a coil, In the heating step, the adherend is continuously fed at a speed of 1 m per minute or more. The method for producing a porous structure according to claim 1 .

3. In the compounding step, the core material and the child particles are dry-mixed to form the beaten-in state or the adhered state. The method for producing a porous structure according to claim 1 .

4. In the spraying step, the numerous composite particles produced in the compounding step are sprayed onto the adherend by a spraying device, and a DC electric field is applied between the spraying device and the adherend, so that the numerous composite particles are charged with an electric charge opposite to that of the adherend and then sprayed. The method for producing a porous structure according to claim 1 .

5. Prior to the spraying step, the temperature is kept in the above range for 10 ４ The method further includes a step of spraying powder particles having a viscosity of less than poise onto the adherend to adhere the particles. The method for producing a porous structure according to claim 1 .

6. In the compounding step, the core material having a viscosity of 10 4 poise or more at a specific temperature is compounded with the child particles having a viscosity of less than 10 4 poise at the specific temperature, In the spraying step, the numerous composite particles are sprayed onto the adherend, which is a ferromagnetic material at room temperature and has a Curie temperature at which it changes into a paramagnetic material at the specific temperature; In the heating step, the composite particles are heated via the adherend by induction heating using a solenoid coil. The method for producing a porous structure according to claim 1 .

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