JP2022035005A - Method for producing paste in which planes of powder formed of metal or alloy are overlapped through solution of organic compound and producing sheet formed of aggregate of powder in which overlapped planes of the powder are jointed by frictional heat using the paste - Google Patents

Abstract

To provide a production method of a paste formed of an aggregate of powder in which planes of flaky, scaly or flat-state powder formed of metal or alloy are overlapped through a solution of an organic compound.SOLUTION: A method is configured to: produce a paste formed of an aggregate of powder in which planes of the powder are overlapped through a solution of an organic compound; then apply the paste to a substrate for forming a coat. The solution of the organic compound is evaporated from the coat, then a coating sheet formed of the aggregate of the powder in which planes of the powder are overlapped is formed on the substrate, and a plane above the coating sheet is compressed in a uniform manner, overlapped planes are jointed by frictional heat, for forming a sheet formed of an aggregate of jointed powder on the substrate. Then, impact is applied to the substrate, then the sheet is detached from the substrate.SELECTED DRAWING: Figure 1

Description

The present invention produces a paste composed of a collection of flakes, scaly or flat powders made of a metal or an alloy, which are overlapped with each other via a solution of an organic compound. The present invention relates to a method for producing a sheet composed of a collection of powders by joining the overlapping planes of powders by frictional heat using the paste. If the powder is a soft magnetic flat powder, the sheet is used as a sheet having high electromagnetic wave reception sensitivity and absorbing electromagnetic noise, and as a sheet having a high magnetic shielding effect. If the powder is metal flake powder or scale powder, the sheet is an antistatic sheet, an electromagnetic wave shielding sheet, a heat conductive sheet, a sheet having an excellent surface lubricity, wiring for electrical equipment, and electrodes. It is used for such purposes.

There are two types of powder having a flake-like, scaly or flat flat surface made of a metal or an alloy, a soft magnetic flat powder and a flake powder or a scaly powder made of a metal.
First, the background technology relating to the soft magnetic flat powder will be described. If the flat surfaces of the soft magnetic flat powder can be joined to each other, a sheet composed of a collection of the flat powder can be formed, and the complex magnetic permeability of the flat powder can be utilized to obtain a sheet that absorbs electromagnetic noise. In addition, it becomes a sheet that shields magnetism by utilizing the relative magnetic permeability of flat powder.
In recent years, electronic devices such as mobile phones and personal computers that use high-frequency signals have become widespread. For example, some mobile phones, wireless LANs, and the like use high frequency signals ranging from several GHz to 10 GHz. Furthermore, in addition to increasing the frequency of signals used by electronic devices, with the miniaturization, thinning, and higher performance of electronic devices, malfunctions due to electromagnetic interference inside the electronic devices and obstacles due to radiation noise to the outside of the devices Is a problem. For this reason, the CISPR22 standard issued by the International Special Committee on Radio Interference (CISPR) in 2005 regulates electromagnetic noise of up to 6 GHz.

By the way, the absorption energy P of the electromagnetic noise is given by the mathematical formula 1. The first term is the absorption of electromagnetic noise by the soft magnetic material, and magnetic loss occurs depending on the magnitude and frequency of the imaginary part μ "of complex magnetic permeability, and this magnetic loss is replaced by heat. The second term is Electromagnetic noise is absorbed by the dielectric material, and a dielectric loss is generated according to the magnitude and frequency of the imaginary part ε "of the complex dielectric constant, and this dielectric loss is also replaced by heat. The third term is the absorption of electromagnetic noise due to conductivity. Due to the skin effect of a high-frequency electric field, a conductive current flows on the surface to form a resistance film, and this resistance film resists according to the magnitude of conductivity σ. A loss is generated, and this resistance loss is also replaced by heat. Therefore, in the frequency band of electromagnetic noise, if the soft magnetic material has a imaginary part μ "with a complex magnetic permeability of a certain size, or if the dielectric material has a imaginary part ε" of a complex permittivity of a certain size. If you have it, electromagnetic noise over a certain frequency band will be absorbed. In Equation 1, E is the magnitude of the electric field in the electromagnetic noise, H is the magnitude of the magnetic field in the electromagnetic noise, f is the frequency of the electromagnetic noise, and σ is the conductivity. When the magnetic material receives an alternating magnetic field due to electromagnetic noise, a phase delay occurs in the change in magnetic flux density, and the magnetic permeability is μ'-jμ ", which is the difference between the real part μ'and the imaginary part μ'. Given. Or, when the dielectric receives an alternating electric field in electromagnetic noise, a phase delay occurs in the change in the electric flux density, and the permittivity is given by the difference ε'-jε "between the real part ε'and the imaginary part ε'. Be done.
(Number 1)
P = πfμ "H ² + πfε" E ² + 1/2 · σE ²

Conventionally, the performance of a sheet that absorbs electromagnetic noise has been performed based on the magnetic permeability of the soft magnetic material forming the sheet. That is, for electromagnetic noise up to around 100 MHz, the magnetic flux convergence effect due to the real part μ'of the complex magnetic permeability of the soft magnetic material shields the magnetic field and brings about the magnetic shield effect. In addition, the magnetic loss effect due to the imaginary part μ of complex magnetic permeability has the effect of absorbing electromagnetic noise and converting it into heat to suppress electromagnetic noise. However, many soft magnetic materials start from a frequency before 100 MHz. The real part of the complex magnetic permeability decreases, and the larger the value of the real part, the sharper the decrease. This phenomenon is the limit of the snake that the larger the real part of the complex magnetic permeability of ferrite, the lower the real part when it exceeds 10 MHz. On the other hand, the imaginary part of the complex magnetic permeability rapidly increases from the frequency before the frequency at which the real part shows the peak value, shows the peak value at a constant frequency, and decreases as the distance from the frequency showing the peak value increases. However, it does not have the required size in the frequency band exceeding 500 MHz.

On the other hand, if the imaginary part of the complex permittivity of the dielectric material has a certain magnitude in the frequency band exceeding 500 MHz, the dielectric loss of the dielectric material based on Equation 1 absorbs the electromagnetic noise in the frequency band exceeding 500 MHz. Will be done. That is, it is sufficient that the dipole of the dielectric (this is called orientation polarization) cannot follow the change of the electric field of 500 MHz or more, and the dielectric dispersion in which the dielectric constant of the dielectric decreases occurs. This phenomenon is a phenomenon in which a phase delay occurs in the change in the electric flux density in the alternating electric field of the electromagnetic noise described in the third paragraph. However, in the frequency band of 500 MHz or more, the value of the imaginary part of the complex permittivity of most dielectrics made of solid is small. This will be described below with the value of the imaginary part in the 2.45 GHz microwave used in the microwave oven.
Regarding the sheet made of a composite material that suppresses electromagnetic noise, the imaginary part of the complex dielectric constant at 2.45 GHz of the polymer material that disperses the soft magnetic material is 0.2-0.5 for phenol resin and 0 for urea resin. At .16-0.23, vinyl chloride resin is 0.08-0.25, polyamide resin is 0.12-0.28, cellulose resin is 0.03-0.42, and synthetic rubber is 0. It is 027-0.03, the polyethylene resin is 1.2 × 10 ^-3 , and the polypropylene resin is 4 × 10 ^-4 . The imaginary part of the complex permittivity of any polymer material is small. On the other hand, the imaginary part of the complex permittivity of water, which is a typical polar molecule, is as large as 22.0. The size of the imaginary part of the complex permittivity of water at 2.45 GHz is utilized in the principle of heating food in a microwave oven. That is, when the food is irradiated with microwaves of 2.45 GHz, the water molecules contained in the food cannot follow the change of the electric field, and absorb the microwaves by the dielectric loss and convert them into heat. On the other hand, the imaginary part of the complex permittivity of ice at 2.45 GHz is as small as 2.8 × 10 ^-4 , so that the ice does not melt by microwave irradiation. As described above, except for liquids composed of polar molecules such as water, alcohol, and acetone, the value of the imaginary part of the complex permittivity in the frequency band of 500 MHz or more is small, and electromagnetic noise in the frequency band of 500 MHz or more cannot be absorbed.

By the way, electromagnetic waves have the depth of the epidermis of electromagnetic waves. The depth of the epidermis is the distance at which the electromagnetic field of the electromagnetic wave incident on the sheet made of the soft magnetic material is attenuated to 1 / e (corresponding to 0.368). The depth of the epidermis is inversely proportional to the square root of the product of the frequency of the electromagnetic wave, the complex magnetic permeability of the flat powder, and the conductivity of the flat powder. Therefore, the higher the frequency of the electromagnetic wave, the larger the complex magnetic permeability of the flat powder, and the larger the conductivity of the flat powder, the shallower the depth of the epidermis. Therefore, if the skin effect is utilized, the thickness of the sheet made of a soft magnetic material is thin and the sheet becomes light. Therefore, if the thickness of the sheet made of the soft magnetic material is changed according to the frequency band of the electromagnetic wave to be absorbed and the sheet is formed with the required thickness, the amount of the soft magnetic material used is small and the sheet becomes lightweight. Similarly, for a sheet that shields magnetism, if the thickness of the sheet made of soft magnetic material is changed according to the frequency band of the electromagnetic wave to be shielded and the sheet is configured with the required thickness, the amount of soft magnetic material used is small. , Becomes a lightweight seat.

Patent Document 1 discloses a sheet having a new material composition as a sheet that absorbs electromagnetic waves. That is, it is a sheet that absorbs electromagnetic waves by the fine particles of the magnetic material, and is a polymer material formed on the first magnetic layer made of a polymer material in which the fine particles of the magnetic material are dispersed and the first magnetic layer. It is provided with a non-magnetic layer made of a non-magnetic layer and a second magnetic layer made of a polymer material in which fine particles of a magnetic substance are dispersed, which is formed on the non-magnetic layer. However, the configuration is different from that of the easy axial direction of magnetism in the second magnetic layer.
That is, even if an electromagnetic wave in a direction that cannot be efficiently absorbed by the first magnetic layer is radiated, the electromagnetic wave is efficiently absorbed by the second magnetic layer having an easy-to-magnetize axial direction different from that of the first magnetic layer. It is a sheet that absorbs electromagnetic waves for the purpose of.
However, if the magnetic material that absorbs electromagnetic waves is not fine particles but flat powder having a certain area, it is described in Patent Document 1 if a sheet is formed by randomly joining flat surfaces in the axial direction in which magnetization is easy. It is not necessary to form the three layers, and an inexpensive sheet can be formed.

In Patent Document 2, a higher magnetic permeability is obtained by intentionally removing the composition from the composition of the alloy of Fe-9.6% Si-5.4% Al, which is an alloy powder having the highest magnetic permeability in the past. The flat powder of the alloy having is disclosed.
In Patent Document 2, as a sheet using the flat powder of this alloy, chlorinated polyethylene is dissolved in toluene, the flat powder of the alloy powder is mixed with this solution, further applied to a polyester resin and dried, and then dried. , An example in which a composite sheet is produced by pressing at 130 ° C. and a pressure of 15 MPa is described as a sheet having a high magnetic permeability.
However, the chlorinated polyethylene resin is a non-magnetic material and does not contribute to the absorption of electromagnetic waves and the magnetic shielding. Therefore, the electromagnetic wave absorption performance and the magnetic shield performance of the composite sheet deteriorate depending on the volume ratio of the non-magnetic chlorinated polyethylene resin. Further, it is described that the flat powder of the alloy has a high magnetic permeability when the flatness is 15 or more. However, in order to reflect the magnetic permeability characteristics of flat powder with a large flatness on the composite sheet, the flat surfaces are aligned and overlapped in the same direction as the sheet surface, so that the collection of flat powder efficiently absorbs electromagnetic waves and becomes a magnetic shield. To contribute. However, simply mixing flat powder with a size of several tens of microns or less with a solution of chlorinated polyethylene and applying this mixed solution does not align the flat surface of the flat powder in the same direction as the sheet surface. ..
As described above, even if the magnetic permeability characteristic of the soft magnetic material is excellent, the sheet does not reflect the magnetic permeability characteristic unless the magnetic permeability characteristic of the soft magnetic material is reflected in the structure of the sheet.

Next, the background technology relating to flake powder or scale powder made of metal will be described. If planes of flake powder or scale powder made of metal can be joined to form a sheet consisting of a collection of flake powder or scale powder, it should be used for antistatic sheets, electromagnetic wave shield sheets, wiring of electrical equipment, electrodes, etc. Can be done. Conventionally, such a conductive sheet is formed as a conductive film by using a conductive paste. This conductive paste is composed of a fluid composition in which a conductive filler made of a metal or an alloy is dispersed in a vehicle composed of a resin-based binder and a solvent. When the conductive paste is printed by means such as screen printing, the conductive filler is reflected on the printed matter via the liquid substance, and the liquid substance consisting of the resin binder and the solvent plays a role of carrying the conductive filler. Liquid substances are called vehicles.
In such a conductive paste, the conductive fillers are crimped to each other through the curing of the resin to form a current path by the conductive filler, and the organic component is volatilized by firing and the conductive fillers are sintered to each other. Then, the sintered conductive filler divides it into a firing mold in which a current-carrying path is formed.
The resin-curable conductive paste is a paste-like composition composed of a conductive filler made of a metal powder or an alloy powder and an organic binder in which a thermosetting resin such as an epoxy resin is dissolved. When heat is applied, the thermosetting resin is cured and shrunk together with the conductive filler, and the conductive fillers are pressure-bonded to each other via the cured resin to be in contact with each other, resulting in conductivity. Since this resin-curable conductive paste is heat-treated at a low temperature of about 200 ° C., it is used for forming wiring such as printed wiring boards and circuit boards made of synthetic resin which has little heat damage and is sensitive to heat. ..
On the other hand, the firing type conductive paste is a paste-like composition in which a conductive filler made of metal powder or alloy powder and glass frit are dispersed in an organic vehicle, and is heated and fired at a high temperature of about 900 ° C. Continuity is provided by volatilizing the organic vehicle, then melting the glass frit, and sintering the metal or alloy powders together. At this time, the glass frit bonds a conductive film made of metal powder or alloy powder to the substrate, and the organic vehicle uses the metal powder or alloy powder and the glass frit as a liquid medium capable of printing. Since the firing type conductive paste has a high firing temperature, it cannot be used for printed wiring boards and circuit boards made of synthetic resin, but it is possible to realize low resistance because metal powder or alloy powder is sintered and integrated. For example, it is used as an internal electrode of a multilayer ceramic capacitor.

The conductive paste uses a metal powder or an alloy powder as a conductive filler, and the metal powder or the alloy powder, or the metal powder or the alloy powder and the glass frit are dispersed in a vehicle composed of a resin binder and an organic solvent. It is composed of a dispersion liquid. The conductive film formed by this conductive paste has various problems due to the use of metal powder or alloy powder as the conductive filler and the dispersion of the metal powder or alloy powder.
The first problem is that the resistance value of the conductive film formed by the heat treatment of the conductive paste is higher than the resistance value of the metal powder or the alloy powder. That is, in the resin-curable conductive paste, the insulating thermosetting resin prevents the metal powders or the alloy powders from coming into direct contact with each other. Further, in the firing type conductive paste, the glass frit having low conductivity prevents sintering of metal powders or alloy powders. As a result, the electrical resistance of the wiring, electrodes, electromagnetic wave shielding film, antistatic film, etc. of the electric circuit formed by the heat treatment of the conductive paste increases, the electrical energy is lost, and a heat generation phenomenon is caused, which causes a malfunction. ..
The second issue is the dispersibility of metal powder or alloy powder. That is, if the dispersibility of dispersing a collection of metal powder or alloy powder in the vehicle is poor, the metal powder or alloy powder is unevenly distributed after the heat treatment, and the metal powder or alloy powder cannot come into direct contact with each other. As a result, similarly to the above, the electric resistance of the wiring, the electrode, the electromagnetic wave shielding film, and the antistatic film of the electric circuit formed by the heat treatment of the conductive paste increases.
The third problem is that the metal powder or the alloy powder shrinks when the metal powder or the alloy powder sinters with each other. That is, when the metal powder or alloy powder shrinks, structural defects such as delamination (delamination) between the electrode and the dielectric and cracks in the electrode layer occur in the internal electrode of the laminated ceramics capacitor.
The fourth problem is that metal powders or alloy powders aggregate with each other. Further, the finer the powder, the easier it is to aggregate. When the powder agglomerates, the dispersibility of the powder in the vehicle deteriorates, and as a result, the electric resistance of the conductive film formed by the heat treatment of the conductive paste increases.
All of the above four problems are difficult to solve fundamentally because they are caused by the use of metal powder or alloy powder as the conductive filler and the dispersion medium that disperses the collection of the metal powder or alloy powder.

Various attempts have been made to solve the problem of conductive films using conductive pastes.
For example, in Patent Document 3, a conductive paste is prepared by using a metal powder filler in which a relatively base metal powder is coated with a relatively noble metal, metal nanoparticles coated with a coating agent, and an organic solvent. A conductive paste that constitutes the above and does not contain a resin component as a binder is described. In order to disperse the metal nanoparticles in the conductive paste, the metal nanoparticles are coated with an alkylamine having an affinity for an organic solvent and having a boiling point close to the boiling point of the organic solvent. When the applied conductive paste is heat-treated, metal nanoparticles are precipitated, metal fillers are bonded by the metal nanoparticles, and a conductive film containing no resin component is formed.
However, metal nanoparticles are extremely easy to aggregate, and once aggregated, they are nano-sized particles, so that it is difficult to release the aggregation and it is difficult to handle. Further, when the metal nanoparticles are generated, the generated metal nanoparticles are easily aggregated with each other. For this reason, alkylammine cannot be adsorbed on the generated metal nanoparticles, and the metal nanoparticles are precipitated in a liquid containing alkylammine, the metal nanoparticles are covered with the alkylamine, and the liquid component excluding the alkylammine is removed. By vaporization, metal nanoparticles coated with alkylammine are produced. Therefore, the manufacturing cost of coating the metal nanoparticles with alkylamine greatly exceeds the manufacturing cost of the conductive paste. Therefore, a general-purpose conductive film such as an electric circuit wiring, an electrode, an electromagnetic wave shielding film, and an antistatic film becomes an expensive film. In Patent Document 3, there is a description that metal nanoparticles coated with alkylammine are used as the conductive paste, but there is no description about a production method of coating the metal nanoparticles with alkylamine.

Patent Document 4 describes a conductive paste composed of silver oxide and fatty acid silver having one or more amino groups. In other words, when the coating film coated with the conductive paste is heat-treated, the fatty acid silver salt is decomposed into silver by the heat treatment, and the fatty acid produced by the decomposition or its decomposition product volatilizes, while oxidation with some fatty acids generated by the decomposition. The reaction with silver produces a fatty acid silver salt again, and the cycle in which this fatty acid silver is decomposed into silver and fatty acid is repeated to form a conductive film made of silver.
However, the fatty acid silver having one or more amino groups is an α-amino acid having at least one type of hydroxyl group consisting of 2-aminoisobutyric acid, DL-threonine, DL-serine, DL-norvaline and 6-aminohexane. It is produced by dissolving in a solvent consisting of threonine, methylethylketone, isophorone, α-terpineol and the like, adding silver oxide powder to this solution, and reacting at room temperature for a long time. Therefore, the cost of producing fatty acid silver using the above-mentioned special chemicals greatly exceeds the cost of producing a conductive paste. Therefore, similarly to Patent Document 3 described above, a general-purpose conductive film such as an electric circuit wiring, an electrode, an electromagnetic wave shielding film, and an antistatic film becomes an expensive film.

Japanese Unexamined Patent Publication No. 2008-198873 Japanese Unexamined Patent Publication No. 2007-118114 Japanese Unexamined Patent Publication No. 2014-035974 Japanese Unexamined Patent Publication No. 2010-102884

Sanyo Special Steel Technical Report, VOL. 13, No. 1, 53-61

First, the problems that occur when forming a sheet consisting of a collection of flat powders obtained by joining the flat surfaces of soft magnetic flat powders to each other will be described.
It is also known that when the soft magnetic powder is flattened in the plane direction, which is the easy axial direction of magnetization, the demagnetizing field coefficient becomes smaller, and the larger the flattening ratio, the larger the imaginary portion μ of the complex magnetic permeability. Since the material of the soft magnetic powder is an alloy excluding ferrite, it is conductive. Therefore, the conductive soft magnetic flat powder is the imaginary portion μ of the complex magnetic permeability in the formula 1 described in paragraph 3. The size of "" and the size of conductivity contribute to the absorption of electromagnetic noise. Further, the flattening treatment of the soft magnetic powder is continuous in a short time because the atomized soft magnetic powder or the reduced soft magnetic powder is subjected to the attritor treatment by the media stirring type mill without relying on the long-time batch processing by the ball mill. Flat powder is obtained and manufactured by an inexpensive processing process.
On the other hand, if a sheet is formed by superimposing the flat surfaces of soft magnetic flat powder and joining the overlapping flat surfaces together, a sheet with a large area can be formed with a small amount of flat powder used. .. In addition, if the imaginary part of the complex magnetic permeability of all the flat powder has a certain size and the flat surface forms the sheet surface, the flat surface participates in the absorption of the electromagnetic wave, the reception sensitivity of the electromagnetic wave is high, and the electromagnetic wave is high. It becomes a sheet with high performance to absorb. This sheet maximizes the flattening effect of soft magnetic flat powder. Further, if the thickness of the sheet can be freely changed according to the frequency band of the electromagnetic wave to be absorbed, the skin effect can be utilized, the amount of flat powder used is small, and the sheet becomes lightweight.
On the other hand, the size of the imaginary part of the complex magnetic permeability of the soft magnetic flat powder depends on the frequency band of the electromagnetic wave. Further, depending on the material of the soft magnetic powder, the size of the imaginary part of the complex magnetic permeability of the flat powder and the frequency characteristic of the imaginary part of the complex magnetic permeability change. Therefore, a plurality of types of soft magnetic flat powders have a constant size in the imaginary part of the complex magnetic permeability in different frequency bands, and the frequency characteristics of the imaginary part of the complex magnetic permeability of each flat powder are different. In the case of multiple types of flat powder having the frequency characteristics of the imaginary part of complex magnetic permeability that complement each other in different frequency ranges, if the flat surfaces of the multiple types of flat powder can be overlapped and the overlapping flat surfaces can be joined. Absorbs electromagnetic noise in a wide frequency band.
Further, a sheet made of a collection of flat powders obtained by superimposing the flat surfaces of soft magnetic flat powders and joining the overlapping flat surfaces to each other becomes a sheet that shields magnetism. That is, the larger the magnetic permeability of the flat powder in the DC magnetic field and the smaller the magnetic resistance, the easier it is for the magnetic field lines to flow to the sheet, and a larger magnetic shielding effect can be obtained. On the other hand, since the magnetic resistance is inversely proportional to the magnetic permeability, a sheet in which the flat surfaces of soft magnetic flat powder having a large relative magnetic permeability are overlapped and the overlapping flat surfaces are directly bonded to each other becomes a sheet having a high magnetic shielding effect. .. Further, since a sheet having a large area can be formed with a small amount of flat powder used and the flat surface forms a sheet surface, all the flat powder participates in the magnetic shield, and the effect of the magnetic shield is enhanced. Furthermore, by changing the thickness of the sheet according to the frequency band of the electromagnetic wave to be shielded, the skin effect can be utilized, the amount of flat powder used is small, and the sheet becomes lightweight.
As described above, the collection of flat powders in which the flat surfaces of the soft magnetic flat powders are directly overlapped with each other brings about excellent action and effect as a sheet for absorbing electromagnetic wave noise and as a shielding film for shielding magnetism. However, there has never been a case where the flat surfaces of soft magnetic flat powder are directly bonded to each other.
As described in Patent Document 2, the conventional sheet is a sheet made of a composite material that vaporizes the organic solvent in the binder and bonds the flat powders to each other through the bonding of the solid polymer material. However, since the polymer material has different properties from the soft magnetic flat powder, the properties of the polymer material are reflected in the sheet. In this way, when soft magnetic flat powders are bonded to each other through the bonding of solid dissimilar materials that occupy a certain volume, the properties of the dissimilar materials are reflected and the unique properties of the soft magnetic flat powders are sacrificed. Become. Also, the flat surface does not form a sheet surface.
On the other hand, if a sheet can be formed by a collection of flat powders in which the flat surfaces of the soft magnetic flat powders are overlapped and directly bonded, the amount of the flat powder used to form the sheet is reduced and the soft magnetic flat powder is used on the sheet. The properties of the powder and the flat surface are reflected. Furthermore, if the flat surface forms a sheet surface, all the flat powders can participate in the absorption of electromagnetic waves, or all the flat powders participate in the magnetic shield, and the magnetic properties of the soft magnetic flat powders are most reflected. It becomes a sheet. This makes it an ideal sheet that can maximize the performance of soft magnetic flat powder.

Next, the problems that occur when forming a sheet composed of a collection of flake powder or scale powder obtained by joining planes of flake powder or scale powder made of metal to each other will be described.
The four problems of forming the conductive film described in paragraph 10 can be fundamentally solved if the conductive filler is not used when forming the sheet. Therefore, if a sheet consisting of flake powder or a collection of scale powder in which planes of flake powder or scale powder made of metal are directly bonded to each other can be formed, the four problems will be fundamentally solved.
Therefore, the problem of forming a sheet consisting of a collection of flat powders directly bonded to the flat surfaces of soft magnetic flat powder and the collection of flake powder or scale powder directly bonded to the flat surfaces of metal flake powder or scale powder. The problem of forming a sheet made of the powder is to superimpose the planes of the powder and directly join the overlapping planes, which is a common problem.
However, when a solid other than the powder is used and the planes of the powder are bonded to each other via the solid to form a sheet, the solid occupies a certain volume, and the properties of the solid are reflected in the sheet. Therefore, solids other than powder cannot be used to form the sheet. Further, it is difficult to directly join the planes of the powder to each other because friction is generated when the planes are overlapped with each other. On the other hand, it is possible to superimpose the planes of the powder on top of each other via the liquid. This is because the liquid has the energy to move the molecules freely, and the shape of the liquid changes freely. Therefore, it is possible to use the movement of the liquid to move the powder having a large aspect ratio with the plane facing up, and to superimpose the planes of the powder on each other. Further, since the liquid is used and the planes of the powder are overlapped with each other in the liquid, friction does not occur in the powder. However, in order to form a sheet consisting of a collection of powders in which the planes of the powder are overlapped with each other and the planes are directly bonded to each other, the sheet is opposed to the collection of powders in which the planes of the powder are overlapped with each other via a liquid. Processing is required. Therefore, when processing the sheet, it is necessary to maintain the state of the powder aggregate in which the planes of the powder are overlapped with each other through the liquid.
Therefore, a paste consisting of a collection of powders in which planes of powder are overlapped with each other via a liquid is created, and a sheet consisting of a collection of powders in which the planes of powder are directly bonded is formed using this paste. To do so, the following five processes are required. Therefore, the problem to be solved by the present invention is to find a method in which the following five processes can be easily carried out.
First, a paste consisting of a collection of powders in which planes of powder are overlapped with each other through a liquid is created. On the other hand, in order to process a sheet using the paste, it is necessary to maintain a state in which the planes of the powder are overlapped with each other through the liquid in the coating film to which the paste is applied. Therefore, secondly, the liquid has a constant viscosity, and the liquid is adsorbed on the plane of the powder due to the viscosity, and the planes of the powder are overlapped and adsorbed via the liquid. Further, in order to process the coating film coated with the paste into a sheet, the following two treatments are required. Third, when the liquid is vaporized from the coating film, the planes of the powder overlap each other. Fourth, the overlapping planes are directly bonded to each other, and the powder is processed into a sheet in which the planes are directly bonded to each other. As a result, a sheet in which the planes of the powder are directly bonded to each other is manufactured.
By the way, soft magnetic flat powder and metal flake powder or scale powder have various materials, shapes, and particle size distributions. Therefore, fifthly, the paste can be prepared regardless of the material, shape, and particle size distribution of the powder, and the overlapping planes can be directly joined to each other. As a result, a sheet composed of a collection of various powders can be produced, the sheet manufacturing method has versatility, and sheets having various properties can be used for various purposes. Further, the planes of a plurality of types of powders made of different materials can be joined to each other.
Sixth, the above-mentioned first to fifth treatments are extremely simple treatments using inexpensive materials. As a result, a sheet in which powders having overlapping planes are directly bonded can be manufactured at low cost.
The problems to be solved by the present invention are these six matters, and when these six problems are solved, the planes of the powder are directly bonded to each other for the powder having a plane consisting of various materials, particle shapes and particle size distributions. Can be manufactured. This sheet is an inexpensive sheet that takes advantage of the properties of powder.

In the present invention, the method for producing a paste consisting of a collection of flakes, scaly or flat powders made of a metal or an alloy in which planes of the powders are overlapped with each other via a solution of an organic compound is used.
The viscosity of the solution of the organic compound in which the organic compound is dissolved with a solvent is set from the average thickness, the average particle size and the density of the flake-like, scaly or flat powder made of a metal or an alloy, and the like. The volume of the solution of the organic compound having viscosity is weighed so that the volume is more than three times the volume occupied by the collection of the powders to prepare the solution of the organic compound, and the solution of the organic compound is combined with the solution of the organic compound. The container is filled with the aggregate of the powder, and then the homogenizer device is operated in the container, and the impact is repeatedly applied to the aggregate of the powder via the solution of the organic compound to form the aggregate of the powder. , The powder is separated into individual powders via the solution of the organic compound, the powder is covered with the solution of the organic compound, and then the homogenizer device is taken out from the container, and further, the container is further removed. A paste consisting of a collection of the powders in which the planes of the powders are overlapped with each other via the solution of the organic compound is produced in the container by repeatedly applying vibration accelerations in three directions of front-back, left-right, and up-down. This is a method for producing a paste consisting of a collection of flakes, scaly or flat powders made of a metal or an alloy in which planes of the powder are overlapped with each other via a solution of an organic compound.

That is, in the produced paste, the solution of the organic compound is adsorbed on the powder by the adsorption force according to the viscosity of the solution of the organic compound, and the planes of the powder overlap each other via the solution of the organic compound. .. Therefore, the viscosity of the solution of the organic compound is an important factor in forming the paste. On the other hand, the thickness of the powder varies depending on the material. For example, the thickness of the flat powder of a metal having a high hardness and being difficult to flatten is as thick as 10-20 μm. On the other hand, the thickness of the flat powder obtained by changing the composition of the alloy, lowering the hardness, and facilitating the flattening treatment is as thin as 1-1.5 μm. Further, the thickness of the flake powder or scale powder made of metal is as thin as 0.15-1.0 μm. Therefore, it is necessary to change the thickness of the coating film formed on the base material by applying the paste to the base material according to the thickness of the powder. Therefore, the viscosity of the solution of the organic compound is changed according to the average thickness of the powder. For example, when four layers of thick powder planes having an average thickness of 15 μm are laminated to form a coating film, the thickness of the powder planes alone is close to 60 μm. On the other hand, when a powder having an average thickness of 1 μm is laminated with four layers to form a coating film, the thickness of the powder surface alone is close to 4 μm. Furthermore, the weight of the powder depends on the particle size and density of the powder. For powders having a relatively large particle size and high density, it is necessary to relatively increase the viscosity of the solution of the organic compound and relatively increase the adsorption force of the solution of the organic compound to be adsorbed on the powder. As described above, it is necessary to set the viscosity of the solution of the organic compound constituting the paste according to the average thickness, the average particle size and the density of the powder.
That is, when the average thickness of the powder is thick, and when the average particle size of the powder is large and the density is high, the viscosity of the paste is relatively increased, and the adsorption force for the solution of the organic compound to be adsorbed on the powder. In addition, the planes of the powder are adsorbed to each other via the solution of the organic compound, and the planes of the thick and heavy powder are adsorbed to each other via the solution of the organic compound. It is necessary to form a coating film in which the planes of the powder are adsorbed on each other via the solution of the organic compound. Therefore, the thickness of the coating film becomes thick. On the contrary, when the average thickness of the powder is thin and the average particle size is small and the density is low, the viscosity of the paste is relatively low and the solution of the organic compound is the powder. In addition to reducing the adsorption force that is adsorbed to the body, the planes of the powder that adsorb each other through the solution of the organic compound are also reduced, and the planes of the powder that are thin and light in weight are the organic compounds. It is necessary to form a coating film that is adsorbed via the solution and the planes of the powder are adsorbed via the solution of the organic compound. Therefore, the thickness of the coating film becomes thin. In this way, the viscosity of the solution of the organic compound is set from the average thickness of the powder and the average particle size and density.
On the other hand, along with the viscosity of the solution of the organic compound, the volume ratio of the solution of the organic compound to the paste is also an important factor for forming the paste. In other words, when the volume ratio of the organic compound solution to the paste is small, it becomes a collection of powders in which the planes are joined via a thin organic compound solution, and the paste has reduced properties as a liquid. However, the fluidity of the paste is low. When such a paste having low fluidity is applied to a base material, it becomes difficult to control the thickness of the coating film. That is, it is not possible to form a coating film in which the planes of the powder are overlapped with each other via the solution of the organic compound. Therefore, the volume ratio of the solution of the organic compound in the paste is more than 3 times the volume ratio of the powder aggregate in the paste, and the dissolution of the organic compound having a thickness thicker than 3 times the thickness of the flat surface of the powder. When the planes of the powder are overlapped with each other via the liquid, the paste has the predominant property of the solution of the organic compound, and the paste has fluidity as a liquid. As a result, a coating film having a thickness corresponding to the viscosity of the solution of the organic compound is formed.
As described above, in producing a paste consisting of a collection of powders in which planes of powder are overlapped with each other via a solution of an organic compound, the viscosity of the solution of the organic compound and the organic content of the paste The volume ratio of the solution of the compound is an important factor.
Here, a method for producing the paste of the present invention will be described.
First, the viscosity of the solution of the organic compound is set from the average thickness of the powder and the average particle size and density. The organic compound is dissolved in a container so as to have this viscosity, and the volume of the solution of the organic compound is weighed so that the volume of the solution of the organic compound is more than 3 times the volume of the collection of powders used. The solution is filled in a container, and a collection of powders is further mixed in the container.
Next, the homogenizer device is operated in the mixed solution in the container, and the impact is repeatedly applied to the powder through the solution of the organic compound, and the aggregate of the powder is collected one by one through the solution of the organic compound. Separate into powders and cover all powders with a solution of organic compound. That is, the powder has a plane having a large aspect ratio, which is the ratio of the average value of the major axis to the minor axis to the thickness. Furthermore, there are variations in the size of the flat surface and the thickness of the powder. When handling such a collection of powders in an atmospheric atmosphere, the planes overlap each other in a complicated manner. Moreover, since the powder is fine and lightweight, it is difficult to distinguish whether or not the planes overlap each other with the naked eye. On the other hand, when a paste is created using powder in which planes overlap each other and a sheet is formed using this paste, powder in which the planes do not join is generated, and a portion having weak mechanical strength is formed on the sheet. Will be done. Further, if all the overlapping powders can be separated into individual powders, the amount of powders forming the sheet can be reduced. Therefore, it is necessary to perform a process for surely separating the portions where the planes of the powder overlap each other. On the other hand, when trying to separate powders having overlapping planes in an atmospheric atmosphere, frictional force is generated on the overlapping planes, and the separation is not easy. In addition, it is difficult to identify whether or not the planes overlap each other. However, since the volume occupied by the solution of the organic compound in the paste is more than three times the volume occupied by the aggregate of powders in the paste, the paste has fluidity as a liquid. When an impact is applied to the solution of the organic compound by a homogenizer device, the impact spreads over the entire solution of the organic compound, whereby the impact is surely applied to the portion where the planes of the powder overlap each other, and the powder is generated. Due to its light weight, overlapping planes can be easily separated from each other. As a result, the powder on which the planes overlap is surely separated. When an ultrasonic homogenizer is used as the homogenizer, the generation of bubbles and the disappearance of a huge number of bubbles, which are two orders of magnitude smaller than the plane of the powder and the disappearance of bubbles, are repeated in the solution of the organic compound ( This phenomenon is called cavitation), and a shock wave when bubbles burst is continuously generated in the entire solution of the organic compound, and the powder on which the planes overlap is separated into individual powders in a short time. .. As a result, all the powder is covered with the solution of the organic compound. On the other hand, since the solution of the organic compound is adsorbed on the powder by the adsorption force according to the viscosity of the solution of the organic compound, the solution of the organic compound does not peel off from the powder in the subsequent treatment. Therefore, the planes of the powder do not overlap again. After this, the homogenizer device is taken out of the container.
Further, vibration acceleration in three directions of front-back, left-right, and up-down is repeatedly applied to the container to produce a paste consisting of a collection of the powder in which the planes of the powder are overlapped with each other via the solution of the organic compound. That is, in the treatment using the homogenizer device, all the powders are covered with the solution of the organic compound. When vibration acceleration is applied to a container filled with such a collection of powders, the solution of the organic compound, which occupies a volume more than three times the volume of the powder, moves in the direction of the vibration acceleration with the powder. At this time, since the powder has a plane having a large aspect ratio, the powder moves in the direction of vibration acceleration with the plane facing up, and the rearrangement of the powder proceeds with the plane facing up, so that the planes are the solutions of the organic compound. Overlap through. As a result, a collection of powders having overlapping planes spreads over the entire container. Finally, the vibration acceleration in the vertical direction is applied to stop the vibration to the container. As a result, a paste consisting of a collection of powders in which planes are overlapped with each other via a solution of an organic compound is produced by spreading over the entire container.
As a result, a paste consisting of a collection of the powders in which the planes of the powders are overlapped with each other via the solution of the organic compound is formed in the container, and the first problem described in paragraph 16 is solved. In addition, since the solution of the organic compound is adsorbed on the plane of the powder by the adsorption force according to the viscosity of the solution of the organic compound, when the paste is applied to the substrate, the organic compound is dissolved from the plane of the powder. The liquid does not peel off. Further, since the planes of the powder overlap each other via the solution of the organic compound having a thickness of 3 times or more, the paste has fluidity as a liquid. Therefore, when the paste is applied to the substrate, a coating film is formed with a thickness corresponding to the viscosity of the solution of the organic compound. In this coating film, the flat surfaces of the powder overlap each other via the solution of the organic compound, and the flat surfaces of the powder form the coating film surface. This solves the second and third problems described in paragraph 16. Further, when the solution of the organic compound is vaporized from the coating film, the coating film becomes a collection of the powders in which the planes of the powder directly overlap each other and the planes of the powder form the coating film surface. Further, if the overlapping planes are joined to each other, the coating film becomes the sheet in which the planes directly overlap each other and the planes form the sheet surface. This solves the fourth problem described in paragraph 16. Furthermore, even if the material, shape, and particle size distribution of the powder used change, the viscosity of the solution of the organic compound is set according to the average thickness and average particle size and density of the powder, and the paste is made by the same method. Can be manufactured. This solves the fifth problem described in paragraph 16.
Next, the action and effect of the paste in the present invention will be described.
The method for producing this paste is to prepare a mixture consisting of a solution of an organic compound and a collection of powders, operate a homogenizer device in the mixture, and repeatedly apply vibration acceleration in three directions to the container. Consists of. Therefore, the paste can be produced at a low cost. Further, powder is a general-purpose industrial material, and organic compounds and solvents are general-purpose industrial chemicals. Therefore, the paste raw material is inexpensive. Therefore, an inexpensive paste can be produced at a low cost. If this paste is applied to form a coating film, the solution of the organic compound is vaporized from the coating film, and the overlapping planes are joined together, the planes directly overlap each other and the planes form the sheet surface. A sheet consisting of a collection of bodies is formed. Therefore, the sheet can be formed at a low cost. As a result, the sixth problem described in paragraph 16 is solved, and all the problems described in paragraph 16 are solved.
Further, since the method for producing this paste comprises the above-mentioned three treatments, there are no restrictions on the material, shape, and particle size distribution of the powder used. Therefore, using this paste, it is possible to create a sheet consisting of a collection of powders whose flat surfaces overlap each other and form a sheet surface, and it is possible to form a sheet having a large area with a small amount of powder used. The powder acts as a sheet. This sheet is a sheet that maximizes the functions based on the material of the powder. Therefore, by using the paste in the present invention, an epoch-making sheet can be formed.

In the method for producing the paste described in paragraph 17, the flat powder made of the metal or alloy described in paragraph 17 is soft magnetic made of any of iron, permalloy, silicon steel, sentust or electromagnetic stainless steel. 17 paragraphs, wherein the soft magnetic flat powder is used as a flat powder made of a metal or an alloy described in paragraph 17, and a paste is produced according to the method for producing a paste described in paragraph 17. Is a method for producing the paste described in 1.

That is, the soft magnetic flat powder made of any of iron, permalloy, silicon steel, sendust or electromagnetic stainless steel is used as the flat powder made of the metal or alloy described in paragraph 17, and is described in paragraph 17. When a paste is produced according to the method for producing the above-mentioned paste and a sheet in which the flat surfaces of the flat powder are directly bonded to each other is formed by using this paste, it can be used as a sheet for shielding magnetism and absorbing or absorbing electromagnetic noise. , Can be used as a sheet to prevent interference of electromagnetic noise.
Here, the magnetic properties of the soft magnetic flat powder will be described. The soft magnetic flat powder made of iron and permalloy has a large initial relative permeability and maximum specific magnetic permeability, and a sheet consisting of a collection of flat powders in which the flat surfaces of the flat powders are directly bonded to each other is effective as a sheet for shielding magnetism. Is. In addition, soft magnetic flat powder made of iron, permalloy, silicon steel, sendust or electromagnetic stainless steel has a constant value in the imaginary part of the complex magnetic permeability in the unique frequency band, so the flat surfaces of the flat powder are directly connected to each other. A sheet made of a collection of bonded flat powders is effective as a sheet that absorbs electromagnetic noise or prevents electromagnetic noise from interfering in a unique frequency band. This will be described below from the magnetic properties of each soft magnetic flat powder.
First, the flattening of iron will be described. Among the soft magnetic materials made of ferromagnetic metals, iron is the only one that has a constant magnetic permeability in an alternating current magnetic field. Electromagnetic soft iron, which has similar magnetic characteristics to pure iron, has an initial relative permeability of 150 and a maximum relative permeability of 1 × 10 ⁴ in a DC magnetic field. On the other hand, nickel has a small initial relative permeability of 110 and a maximum relative permeability of 600. On the other hand, the relative magnetic permeability in an AC magnetic field of 100 kHz is 100 for electromagnetic soft iron and close to 1 for nickel. The saturation magnetic flux density of electromagnetic soft iron is the largest among soft magnetic materials, which is 2.2 tesla. Therefore, the sheet in which the flat surfaces of the iron flat powder are overlapped with each other effectively acts as a shield film that shields magnetism. In particular, it is effective as a magnetic shield for equipment that generates a strong magnetic field, such as MRI (abbreviation of Magnetic Resonance Imaging, which means a magnetic resonance imaging) and a power transformer. On the other hand, iron has a Vickers hardness of 2.45 GPa and is a relatively hard metal. In addition, iron powder includes reduced iron powder and atomized iron powder. Reduced iron powder has many pores and is relatively easier to flatten than atomized iron powder, but it is flat because of its high hardness. Is thick. Therefore, the flat powder of the reduced iron powder has a larger flatness than the atomized iron powder, and the imaginary portion of the complex magnetic permeability has a constant size in the frequency band of 100 kHz-10 MHz. Therefore, the sheet made of the flat powder of the reduced iron powder acts as a sheet for absorbing electromagnetic noise in the frequency band of 100 kHz to 10 MHz or preventing interference of electromagnetic noise. The skin depth of the 100 kHz electromagnetic wave of the reduced iron powder is 50 μm. Therefore, the flat powder made of reduced iron powder exhibits excellent performance as a magnetic shield for equipment that generates a strong magnetic field. Further, it is effective in a limited frequency band as a sheet for absorbing electromagnetic noise or preventing interference of electromagnetic noise. Therefore, the flat powder of the reduced iron powder is used as the flat powder made of the metal described in paragraph 17, and the paste is produced according to the method for producing the paste described in paragraph 17, and the paste is used to produce the flat powder. When a sheet made of a collection of flat powders directly bonded to each other is formed, it can be used as a sheet for shielding magnetism and as a sheet for absorbing electromagnetic noise or preventing interference of electromagnetic noise.
On the other hand, permalloy is a soft magnetic material having a high magnetic permeability. The larger the magnetic permeability of the flat powder and the smaller the magnetic resistance, the greater the magnetic shielding effect can be obtained. Since the reluctance is inversely proportional to the magnetic permeability, a sheet made of permalloy flat powder having a large magnetic permeability has a high magnetic shielding effect. For example, permalloy, which is 45% nickel, has a large initial relative permeability of 2.5 × 10 ³ and a maximum specific permeability of 2.5 × 10 ⁴ in a DC magnetic field. However, the saturation magnetic flux density is smaller than that of electromagnetic soft iron, which is 0.9 Tesla. On the other hand, permalloy, which is 79% nickel and 4% molybdenum, has a large initial relative permeability of 2 × ^{10 4} and a maximum relative permeability of 2 × 105. However, the higher the nickel content, the more expensive the permalloy. Therefore, a sheet in which the flat surfaces of permalloy flat powder are overlapped with each other is an excellent sheet that shields magnetism. For this reason, in areas where the external magnetic field is relatively small, such as leakage magnetic fields from electrical equipment, AC magnetic fields from current transmission and distribution lines, urban magnetic noise, and environmental magnetic fields, the sheet made of Permalloy flat powder is a sheet that shields magnetism. It is effective as. According to Non-Patent Document 1, the permalloy flat powder containing 50% nickel has an aspect ratio of 38 and an average particle size of 14 μm. Further, the imaginary part of the complex magnetic permeability rises sharply from around 100 MHz, has a peak value of 8.8 at 3.3 GHz, decreases from around 4 GHz, and has a value of 3.5 at 10 GHz. Therefore, in the frequency band of 1-8 GHz, the imaginary part of the complex magnetic permeability has a value of 5 or more, and acts as a sheet for absorbing electromagnetic noise or preventing interference of electromagnetic noise in this frequency band. However, since the imaginary part of the complex magnetic permeability is small, the absorption rate of electromagnetic waves is low. Therefore, permalloy takes advantage of its high magnetic permeability and exhibits excellent performance as a sheet that shields magnetism in a region where the external magnetic field is relatively small. Further, it is effective in a limited frequency band as a sheet for absorbing electromagnetic noise or preventing interference of electromagnetic noise. Therefore, the permalloy flat powder is used as a flat powder made of the alloy described in paragraph 17, and a paste is produced according to the method for producing the paste described in paragraph 17, and this paste is used to prepare the flat powder. When a sheet made of a collection of flat powders directly bonded to each other is formed, it can be used as a sheet for shielding magnetism and as a sheet for absorbing electromagnetic noise or preventing interference of electromagnetic noise.
By the way, in a soft magnetic material made of an alloy, silicon steel made by adding a small amount of silicon to iron, permendur made by adding nickel to iron, sentust made by adding silicon and aluminum to iron, and per made by adding cobalt to iron. There are mendur and electromagnetic stainless steel made by adding chromium and silicon to iron. Of these, silicon steel becomes brittle as the amount of silicon added increases, and the amount of silicon added to silicon steel that can be flattened is less than 10%. If the amount of silicon added is slightly different, the magnetic permeability characteristics of the silicon steel will change significantly. Further, the manufacturing cost of permalloy increases as the amount of nickel added increases, but the magnetic permeability decreases when the amount of nickel added is small, so the amount of nickel added is suppressed to about 50%. In addition, although sendust has high hardness and is brittle, flattening can be performed by adding a small amount of nickel and reducing the amount of silicon added. Further, since permendur is an alloy with cobalt, the manufacturing cost is high, and it is not suitable as a flat powder used for a sheet that absorbs electromagnetic noise or prevents interference of electromagnetic noise. Further, when aluminum is added to the electromagnetic stainless steel, the flattening treatment becomes easy. Therefore, the four types of alloys except permendur can be processed into soft magnetic flat powder. Further, the thickness of the flat powder made of four kinds of alloys falls within the range of 1-1.5 μm. On the other hand, since the hardness of the reduced iron powder is higher than the hardness of the four types of alloys, the thickness of the flat powder made of the reduced iron powder is as thick as 10-20 μm.
On the other hand, as explained in paragraph 15, the larger the flattening ratio of the flat powder, the larger the imaginary portion of the complex magnetic permeability. Further, the absorption of electromagnetic noise depends on the size of the imaginary portion of the complex magnetic permeability of the flat powder and the size of the conductivity. Therefore, in the sheet used for absorbing electromagnetic noise or preventing interference of electromagnetic noise, a flat powder of silicon steel in which the amount of silicon added is less than 10%, and a flat powder of permalloy in which the amount of nickel added is suppressed to nearly 50%. It is possible to use a flat powder of Sendust in which a small amount of nickel is added to reduce the amount of silicon added, and a flat powder of electromagnetic stainless steel to which aluminum is added. However, in the flat powder composed of these four types of alloys, the complex magnetic permeability changes when the composition of the components other than iron changes slightly. Further, since the hardness of each of the four types of alloys is different, the flatness of the flat powder is different, and the size of the imaginary portion of the complex magnetic permeability is different. Furthermore, the frequency characteristics of complex magnetic permeability differ greatly between the four types of alloys, and even for the same alloy, the components other than iron differ. Therefore, when creating a sheet used for absorbing electromagnetic noise or preventing interference of electromagnetic noise, the material of the soft magnetic flat powder is properly used according to the frequency band of the absorbed electromagnetic wave. Therefore, a flat powder composed of four kinds of alloys is used as a flat powder composed of the alloy described in paragraph 17, and a paste is produced according to the method for producing a paste described in paragraph 17, and this paste is used. When a sheet made of a collection of flat powders in which the flat surfaces of the flat powders are directly bonded to each other is formed, it can be used as a sheet that absorbs electromagnetic noise or prevents electromagnetic noise from interfering with each other.
By the way, in the paste in the present invention, as described in paragraph 18, the solution of the organic compound is adsorbed on the flat powder according to the viscosity of the solution of the organic compound, and the flat surfaces of the flat powder are organic. Overlapping via a solution of the compound. Therefore, the viscosity of the solution of the organic compound is a factor that determines the properties of the paste. On the other hand, since the hardness of the soft magnetic flat powder is different, the thickness of the flat powder varies depending on the material. For example, the thickness of the flat powder obtained by flattening the reduced iron powder, which has high hardness and is difficult to flatten, is as thick as 10-20 μm. On the other hand, the thickness of the flat powder obtained by adding a small amount of nickel to sendust, which is a ternary alloy composed of iron, silicon, and aluminum, to reduce the amount of silicon added, and to facilitate the flattening treatment, is 1-1. It is as thin as 5 μm. Therefore, it is necessary to change the thickness of the coating film formed by applying the paste to the base material according to the thickness of the flat powder. In addition, the weight of the flat powder varies with the thickness of the flat powder and the particle size and density of the flat powder. For example, the weight of the flat powder of the reduced iron powder having a particle size of 100 μm and a thickness of 15 μm is 0.927 × 10 ^-6 g. On the other hand, the weight of the flat powder of Sendust having a particle size of 40 μm and a thickness of 1 μm is 0.86 × ^10-8 g. The density of iron is 7.8 g / cm ³ , and the density of sendust is 7.6 g / cm ³ , both of which are close in density. Therefore, the reason why the weight of the flat powder of the reduced iron powder is two orders of magnitude larger than the weight of the flat powder of Sendust is due to the difference in the thickness and the particle size of the flat powder. Therefore, as described in paragraph 18, it is necessary to change the viscosity of the solution of the organic compound constituting the paste according to the average thickness and the average particle size and density of the flat powder. The density of the soft magnetic flat powder made of a metal or an alloy is in the range of 7.7-8.3 g / cm ³ .
On the other hand, as described in paragraph 18, the viscosity of the solution of the organic compound and the volume occupied by the solution of the organic compound in the paste are also important factors that determine the properties of the paste. Therefore, the volume occupied by the solution of the organic compound in the paste is set to be more than three times the volume occupied by the collection of soft magnetic flat powder in the paste, and the paste is made to have fluidity as a liquid.
In the method for producing this paste, a mixture consisting of a solution of an organic compound and a collection of soft magnetic flat powder is prepared, a homogenizer device is operated in the mixture, and vibration acceleration in three directions is repeated in a container. It consists of three additional processes. Therefore, there are no restrictions on the material, shape, particle size distribution, and hardness of the flat powder used in producing the paste. Further, the flat powders are composed of a collection of flat powders in which the flat powders are overlapped with each other via the solution of the organic compound, and the solution of the organic compound is vaporized. Becomes an overlapping sheet.
Further, when the flat surfaces of the soft magnetic flat powder are joined to each other to form a sheet on which the flat powder is laminated, there is no limitation on the number of layers on which the flat powder is laminated. Therefore, if a flat powder having a large magnetic permeability is used, the depth of the epidermis of the flat powder is obtained, and the sheet is formed with a thickness close to the depth of the epidermis, a sheet having a large area can be formed with a small amount of the flat powder used. All the flat powder can participate in the magnetic shield, and the effect of the magnetic shield is enhanced. This sheet is a sheet that maximizes the magnetic shielding effect of the flat powder. Such a sheet can be formed by using the paste in the present invention.
In addition, if the soft magnetic flat powder has a certain size of the imaginary part of the complex magnetic permeability in a specific frequency band and the sheet is composed of this collection of flat powder, the amount of the flat powder used is small and the area is wide. Sheets can be formed. Further, when the flat surfaces of the soft magnetic flat powder are joined to each other to form a sheet on which the flat powder is laminated, there is no limitation on the number of layers on which the flat powder is laminated. Therefore, if the depth of the epidermis of the flat powder is obtained from the frequency characteristics of the conductivity and the complex magnetic permeability of the soft magnetic flat powder used, and the sheet is formed with a thickness close to the depth of the epidermis, the amount of the sheet is small. Efficiently absorbs electromagnetic noise with flat powder. In this way, the sheet maximizes the electromagnetic wave absorption effect of the flat powder.
By using the paste in the present invention, such an epoch-making sheet can be formed.

The method for producing the paste described in paragraph 19 is that the soft magnetic flat powder described in paragraph 19 is a flat powder composed of a plurality of types of alloys excluding the flat powder of reduced iron powder, and is composed of the plurality of types of alloys. The frequency characteristics of the imaginary part of the complex magnetic permeability of the flat powder are different from each other, and the frequency characteristics of the imaginary part of the complex magnetic permeability of each flat powder complement each other in different frequency ranges. A flat powder made of a plurality of types of alloys having a characteristic and the frequency characteristic of the imaginary portion of the complex magnetic permeability is used as the soft magnetic flat powder described in paragraph 19, and a paste is produced according to the method described in paragraph 19. , 19 is a method for producing the paste described in paragraph 19.

That is, as described in paragraph 15, when the soft magnetic powder is flattened in the plane direction, which is the easy axial direction of magnetization, the demagnetic field coefficient becomes smaller, and the larger the flattening ratio, the larger the imaginary portion μ of the complex magnetic permeability. Further, the frequency characteristic of the imaginary part of the complex magnetic permeability of the flat powder changes greatly depending on the material of the flat powder. Therefore, in the soft magnetic flat powder made of a plurality of types of alloys, the frequency characteristic of the imaginary part of the complex magnetic permeability of the flat powder is changed. Are different from each other, and if the frequency characteristics of the imaginary part of each complex magnetic permeability are the frequency characteristics of the imaginary part of the complex magnetic permeability that complement each other in different frequency ranges, the soft magnetic flat powder composed of these multiple types of alloys. If a sheet is formed using the above, the sheet absorbs electromagnetic noise in a wide frequency band, and becomes a sheet for preventing electromagnetic noise interference due to electromagnetic interference with each other. On the other hand, soft magnetic flat powder. Among them, only the flat powder of reduced iron powder has a higher hardness than other soft magnetic flat powder, so that the thickness of the flat powder is as thick as 10-20 μm. The other soft magnetic flat powder is atomized soft magnetic. In order to reduce the hardness of the powder or reduced soft magnetic powder, the composition of the alloy is finely adjusted to enable flattening, and the thickness deviation is within the range of 1-1.5 μm. Therefore, the reduced iron powder. When a collection of flat powder mixed with flat powder made of other materials is dispersed in a solution of an organic compound and vibration acceleration in three directions is applied to this mixture, all flat powder is obtained. The flat surfaces of the powder do not overlap with each other via the solution of the organic compound. Therefore, when producing the paste, the flat powder of the reduced iron powder is removed from the soft magnetic flat powder described in paragraph 19.
That is, in the method for producing the paste described in paragraph 19, as the soft magnetic flat powder described in paragraph 19, a flat powder composed of a plurality of types of alloys excluding the flat powder of reduced iron powder is used, and the plurality of types of alloys are used. The frequency characteristics of the imaginary part of the complex magnetic permeability of the flat powder are different from each other, and the frequency characteristics of the imaginary part of the complex magnetic permeability of each flat powder complement each other in different frequency ranges. With the frequency characteristics of, the aggregate of the flat powder made of the plurality of types of alloys has a constant size of the imaginary portion of the complex magnetic permeability in a wider frequency band, which was difficult with one type of flat powder. Using a collection of flat powders made of multiple types of alloys, a paste is produced according to the method described in paragraph 19, vaporizing a solution of an organic compound from the paste, and joining the flat powders made of multiple types of alloys. For example, a sheet made of a collection of flat powders made of a plurality of types of alloys can be formed. This sheet absorbs electromagnetic noise in a wide frequency band, which was difficult in the past, or prevents interference of electromagnetic noise.
On the other hand, as described in paragraph 15, the flat powder is produced by treating the atomized soft magnetic powder or the reduced soft magnetic powder with an attritor treatment using a media stirring type mill. Therefore, if the material of the flat powder is different, the shape, structure and hardness of the atomized soft magnetic powder or the reduced soft magnetic powder are different, so that not only the flatness but also the shape, particle size distribution and hardness of the flat powder are different. However, as mentioned above, the thickness deviation falls within the range of 1-1.5 μm. By the way, in the production of the paste, as described in paragraph 19, a mixed solution consisting of a solution of an organic compound and a collection of soft magnetic flat powder is prepared, a homogenizer device is operated in the mixed solution, and 3 is placed in a container. It consists of three processes in which the vibration acceleration in the direction is repeatedly applied. Therefore, even if the flat powder is a plurality of types of flat powder having different flatness, shape, particle size distribution, and hardness, the paste can be produced because the three processes for producing the paste are possible.

A method of joining the flat surfaces of the soft magnetic flat powder to each other using the paste produced by the production method described in paragraph 19 to form a sheet composed of a collection of the soft magnetic flat powder is described in paragraph 21. The method of joining the flat surfaces of the flat powders of a plurality of types of alloys to each other using the paste produced by the above-mentioned production method to form a sheet composed of a collection of the flat powders of the plurality of types of alloys is described.
The paste produced by the method described in paragraph 19 or 21 is applied to a substrate to form a coating film composed of the paste on the substrate, and then the solution of the organic compound is vaporized from the coating film. As a result, a film composed of a collection of the flat powders in which the flat powders of the soft magnetic soft powders are overlapped is formed on the base material, or the flat surfaces of the flat powders of a plurality of types of alloys are overlapped with each other. A coating consisting of a collection of flat powders of different types is formed on the substrate, and then the upper plane of the coating is evenly compressed, whereby the flat surfaces of the soft magnetic flat powder are overlapped with each other. Friction heat is generated at the site, and the overlapping flat powders are bonded to each other by the friction heat, and a sheet composed of a collection of the bonded soft magnetic flat powders is formed on the base material, or the plurality of types. Friction heat is generated at the portion where the flat powders of the alloy overlap each other, and the overlapping flat powders are bonded to each other by the frictional heat. The production according to paragraph 19, wherein the sheet formed on the base material is subsequently repeatedly subjected to impact acceleration on the side surface of the base material, the sheet formed on the base material is peeled off from the base material, and the sheet is taken out. Using the paste produced by the method, the flat surfaces of the soft magnetic flat powder are joined to each other to form a sheet composed of a collection of the soft magnetic flat powder, or the paste produced by the production method described in paragraph 21. Is a method of joining flat surfaces of flat powders of a plurality of types of alloys to form a sheet composed of a collection of flat powders of the plurality of types of alloys.

That is, when the paste produced by the method described in paragraph 19 or paragraph 21 is applied to the base material, a coating film having a thickness corresponding to the viscosity of the paste is formed on the base material. After that, the solution of the organic compound is vaporized from the coating film. As a result, the coating film becomes a film formed of a collection of the flat powders in which the flat surfaces of the soft magnetic flat powders are overlapped with each other. Or, the coating film becomes a coating film composed of a collection of flat powders in which flat surfaces of flat powders of a plurality of types of alloys are overlapped with each other. In addition, the plane above the coating is evenly compressed. For example, a plate having the same shape as the coating is placed on the coating, and a weight of tens to hundreds of kilograms is placed on the plate depending on the area of the coating, and the plane above the coating is evenly compressed. do. At this time, frictional heat is generated at a portion where the flat surfaces that overlap each other come into contact with each other. Due to this frictional heat, the flat surfaces of the flat powder are directly bonded to each other. In other words, the flat surface of the flat powder has the surface roughness associated with the processing of the flat treatment, the flat powder cannot move due to the applied compressive stress, the applied compressive stress does not decrease, and the overlapping flat surfaces are evenly distributed. Compress to. At this time, most of the compressive stress applied to the flat surfaces is converted into frictional heat generated at the sites where the flat surfaces come into contact with each other. That is, the atomized powder made of a metal or an alloy, or the flat surface of the flat powder obtained by flattening the reduced powder has surface roughness, that is, unevenness due to processing. Therefore, when a group of flat surfaces in which flat surfaces are directly overlapped with each other is compressed, the flat surfaces have irregularities, so that the local part on the pressurizing side comes into contact with the local part on the pressurized side. However, a large number of them are formed on the overlapping flat surfaces, and frictional heat is generated in these parts. By this frictional heat, a large number of parts where the flat surfaces come into contact with each other are joined, and a sheet composed of a collection of the joined flat powders is formed on the base material. After that, the weight and the plate material are removed, and an impact is repeatedly applied to the side surface of the base material on which the sheet is formed, and the sheet is peeled off from the base material. For example, an impact acceleration of 0.4-1.0 G is applied depending on the area of the sheet. After this, the sheet is taken out from the base material.
In the flat powder of a plurality of types of alloys, the hardness of the flat powder is different because the material of the flat powder is different. However, in order to enable flattening treatment, the difference in hardness between the flat powders of the plurality of types of alloys is small. Further, the difference in the thickness of the flat powders of the plurality of types of alloys is small. On the other hand, even if there is a difference in the thickness of the flat powder or a difference in the hardness of the flat powder in the flat powder of a plurality of types of alloys, when the group of flat powder in which the flat surfaces are overlapped is compressed, the flat powder is flattened. A portion where the flat surfaces are in contact with each other is surely formed in the portion where the surfaces overlap each other. Friction heat is generated in this part, and the overlapping flat surfaces are joined together. It should be noted that it is not necessary to plastically deform the flat powder because frictional heat may be generated at the contact portion of the overlapping flat surfaces when the collection of the flat powder is compressed. As a result, the flat surfaces of the flat powders of a plurality of types of alloys are joined by frictional heat.
This sheet has the following effects.
First, the sheet is composed only of the flat powder obtained by directly joining the flat surfaces of the flat powder by frictional heat. Therefore, the sheet has the property of flat powder.
Secondly, since the paste is applied to the base material to form the sheet, there are no restrictions on the area and shape of the sheet. Further, as described above, a paste can be produced regardless of the shape, size, particle size distribution, and hardness of the flat powder. Further, by applying a paste, vaporizing the solution of the organic compound from the coating film, and further applying compressive stress, the overlapping flat surfaces are joined by frictional heat to form a sheet composed of a collection of flat powders. Therefore, the method for producing this sheet can form a sheet with versatility for soft magnetic flat powder excluding flat reduced iron powder.
Thirdly, a sheet in which flat surfaces of flat powder made of a soft magnetic material having a large relative permeability are overlapped with each other is a sheet having a high magnetic shielding effect. Furthermore, if the thickness of the sheet is made close to the depth of the epidermis of the flat powder, a sheet with a large area can be formed with a small amount of flat powder used, and all the flat powder participates in the magnetic shield, and the effect of the magnetic shield is obtained. Will increase.
Fourth, the soft magnetic flat powder made of multiple types of alloys has different frequency characteristics of the imaginary part of complex magnetic permeability, and the frequency characteristics of the imaginary part of each complex magnetic permeability complement each other in different frequency ranges. Due to the frequency characteristics of the imaginary part of the matching complex magnetic permeability, the sheet formed by using soft magnetic flat powder made of a plurality of types of alloys absorbs electromagnetic noise in a wide frequency band, which was difficult in the past. In addition, if the thickness of the sheet is made close to the depth of the skin of the flat powder of multiple types of alloy, a sheet with a large area can be formed with a small amount of flat powder used, and all the flat powder absorbs electromagnetic noise. Participate and enhance the absorption effect of electromagnetic noise.

The flake-like or scaly powder made of a metal or alloy described in paragraph 17 is a flake powder or scaly powder made of any material of silver, copper, brass, nickel, zinc or aluminum, and the flake powder or scaly powder. The scaly powder is used as a flake-like or scaly powder made of the metal or alloy described in paragraph 17, and the paste is produced according to the method for producing the paste described in paragraph 17, to produce the paste described in paragraph 17. The method.

In other words, the flake powder is made of silver, copper, brass, nickel or zinc excluding aluminum, and the metal powder is beaten with a large number of metal punches using a stamp mill to form thin flakes. It is stretched and flattened to produce flaky flake powder. When the flake powder is hit with a large number of metal pestle, undulations are formed on the surface and the flatness is not high. On the other hand, with respect to aluminum, since the activity of the fine particles is high, the fine particles produced by the atomizing method are flattened with a wet ball mill to produce flaky scale powder. This aluminum scale powder has a surface roughness due to flattening treatment with a wet ball mill. These flake powders or scale powders have a high aspect ratio, which is the ratio of the thickness to the major axis. Therefore, if the planes are overlapped with each other, a sheet having a certain area can be formed by collecting a small amount of flake powder or scale powder. Further, since the surface of the flake powder is smooth, the coefficient of friction of the surface is as small as 0.20-0.25. For this reason, the flake powder of metal has a lubricity on the surface and also has conductivity and thermal conductivity based on the material.
On the other hand, the heat resistant temperature of the flake powder of metal other than aluminum is determined by the softening point, and even the lowest electrolytic copper has a high softening point of 800 ° C. Moreover, since the metal does not have low temperature brittleness, it can be used at extremely low temperatures. Therefore, the sheet composed of a collection of flake powder can be used in a harsh environment such as high temperature, ultra-low temperature, ultra-vacuum, and ultra-high pressure to which oil lubrication cannot be applied. Further, the load bearing capacity is as high as 600 MPa. Therefore, when the collection of flake powder is compressed, the planes of the flake powder withstand the compressive stress, frictional heat is generated at the contact portion where the planes overlap each other, and the planes are joined by the frictional heat.
On the other hand, the softening point of aluminum is as low as 350 ° C. Therefore, when the aluminum scale powders are joined together by frictional heat, the contact portion of the aluminum scale powders is softened. However, the time for which frictional heat is generated is short, the generation of frictional heat is limited to the contact portion, and the entire scale powder is not softened. For this reason, the contact portions of the softened aluminum scale powder are joined to each other by frictional heat. As a result, a lightweight sheet having both thermal conductivity and conductivity is formed.
The metal flake powder has a smooth surface, but the surface is not flat and has a peculiar undulation. Therefore, when the planes on which the planes are directly overlapped are compressed, the planes have undulations, so that a local part on the pressurizing side comes into contact with the local part on the pressurizing side. Friction heat is generated at the site. By this frictional heat, the overlapping planes are joined to each other, and a sheet consisting of a collection of joined flake powders is formed on the base material. The aluminum scale powder is flattened by a wet ball mill to form irregularities on the surface. For this reason, when a collection of scale powders on which planes overlap each other is compressed, local parts where the planes come into contact with each other are formed, and frictional heat is generated in these parts, similar to flake powder. By this frictional heat, the overlapping planes are joined to each other, and a sheet consisting of a collection of joined scale powders is formed on the base material.
By the way, in the paste in the present invention, as described in paragraph 18, the solution of the organic compound is adsorbed on the powder according to the viscosity of the solution of the organic compound, and the planes of the powder are organic. Adsorbs through the solution of the compound. Therefore, the viscosity of the solution of the organic compound is a factor that determines the properties of the paste. On the other hand, the thickness of metal flake powder or scale powder has a width of 0.2-1 μm depending on the material, but within the grade of the flake powder or scale powder product used, the thickness deviation is within 0.1 μm. .. Further, the particle size of the flake powder or the scale powder differs depending on the product because the flattening conditions are different even if the material is the same. The density of the metal is 2.7 g / cm ³ for aluminum, 10.5 g / cm ³ for silver, 9.0 g / cm ³ for copper, 8.7 g / cm ³ for brass, and 8 for nickel. At 9.9 g / cm ³ , zinc is 7.1 g / cm ³ . Therefore, the viscosity of the solution of the organic compound constituting the paste varies depending on the average thickness of the flake powder or the scale powder, the average particle size, and the density of the metal.
Further, as described in paragraph 18, the viscosity of the solution of the organic compound and the volume occupied by the solution of the organic compound in the paste are also important factors that determine the properties of the paste. Therefore, the volume occupied by the solution of the organic compound in the paste is more than three times the volume occupied by the collection of flake powder or scale powder in the paste, and the paste is made to have fluidity as a liquid.
In the method for producing this paste, a mixture consisting of a solution of an organic compound and a collection of flake powder or scale powder composed of metal is prepared, a homogenizer device is operated in the mixture, and the container is vibrated in three directions. It consists of three processes of repeatedly applying acceleration. Therefore, there are no restrictions on the material, shape, and particle size distribution of the metal flake powder or scale powder used in producing the paste. Further, the paste consists of a collection of powders in which the planes of flake powder or scale powder are overlapped with each other via the solution of the organic compound, and the solution of the organic compound is vaporized, and further, the overlapping planes are joined. , It becomes a sheet in which planes overlap each other. Therefore, a sheet having a large area can be formed with a small amount of powder used. This sheet is an antistatic sheet, an electromagnetic wave shielding sheet, or a sheet having an excellent lubricity on the surface. Such a sheet can be formed by using the paste in the present invention.

Using the paste produced by the method described in paragraph 25, the parts where the planes of the metal flake powder or the scale powder overlap each other are joined by frictional heat, and the metal flake powder or the scale powder to which the planes are joined are joined together. The method of forming the sheet is
The paste produced by the method described in paragraph 25 is applied to a substrate to form a coating film composed of the paste on the substrate, and then the solution of the organic compound is vaporized from the coating film to form a metal. A coating consisting of a collection of the flake powder or the scale powder on which the planes of the flake powder or the scale powder are overlapped is formed on the substrate, and then the upper plane of the coating is evenly compressed, whereby the said. Friction heat is generated at the portion where the planes of the flake powder or the scale powder overlap each other, and the friction heat joins the planes of the overlapped flake powder or the scale powder to each other, and the flake powder or the scale powder to which the planes are joined is joined. A sheet consisting of a collection of the above is formed on the base material, and then the side surface of the base material is repeatedly impacted to peel off the sheet formed on the base material and take out the sheet. Using the paste produced by the method described in paragraph 25, the parts where the planes of the metal flake powder or the scale powder overlap are joined by frictional heat, and from the collection of the metal flake powder or the scale powder to which the planes are joined. It is a method of forming a sheet.

That is, when the paste produced by the method described in paragraph 25 is applied to the base material, a coating film having a thickness corresponding to the viscosity of the paste is formed on the base material. After that, the solution of the organic compound is vaporized from the coating film. As a result, the coating film becomes a film composed of a collection of the flake powder or the scale powder in which the planes of the metal flake powder or the scale powder are overlapped with each other. In addition, the plane above the coating is evenly compressed. For example, a plate having the same shape as the coating is placed on the coating, and a weight of tens to hundreds of kilograms is placed on the plate depending on the area of the coating, and the plane above the coating is evenly compressed. do. At this time, frictional heat is generated on the planes on which the planes overlap each other. Due to this frictional heat, the flat surfaces of the metal flake powder or scale powder are directly bonded to each other by the frictional heat. That is, the flat surface of the flake powder has undulations associated with the processing of the flake powder. In addition, the surface of the scale powder has a surface roughness due to the processing of the scale powder. Therefore, the flake powder or the scale powder cannot move due to the applied compressive stress, and the applied compressive stress does not decrease, and the overlapping planes are evenly compressed. At this time, most of the compressive stress applied to the plane is converted into frictional heat. In other words, when the planes on which the planes directly overlap each other are compressed, the planes have undulations or irregularities, so that a local part on the pressurizing side comes into contact with the local part on the pressurizing side. , Friction heat is generated in these parts. By this frictional heat, the overlapping planes are joined to each other, and a sheet consisting of a collection of the joined powders is formed on the base material. After that, the weight and the plate material are removed, impact acceleration is repeatedly applied to the side surface of the base material on which the sheet is formed, and the sheet is peeled off from the base material. For example, an impact acceleration of 0.4-1.0 G is applied depending on the area of the sheet. After this, the sheet is taken out from the base material.
This sheet has the following effects.
First, a sheet is composed of only flake powder or scale powder obtained by directly joining flat surfaces of metal flake powder or scale powder by frictional heat. Therefore, the sheet has the property of powder.
Secondly, since the paste is applied to the base material to form the sheet, there are no restrictions on the area and shape of the sheet. Further, as described above, a paste can be produced regardless of the shape, size, particle size distribution, and hardness of the metal flake powder or scale powder. Furthermore, by applying a paste, vaporizing the solution of the organic compound from the coating film, and further applying compressive stress, the overlapping planes are joined by frictional heat to form a sheet consisting of a collection of flake powder or scale powder. do. Therefore, the method for producing this sheet can form a sheet with versatility for metal flake powder or scale powder.
Thirdly, a sheet having a large area can be formed with a small amount of powder used. The sheet will be an antistatic sheet that reflects the properties of the powder, an electromagnetic wave shielding sheet, or a sheet with excellent lubricity.

In the method for producing the paste described in paragraph 17, the solution of the organic compound described in paragraph 17 is an aqueous solution of 1,5-pentanediol or an aqueous solution of glycerin, and the aqueous solution of 1,5-pentanediol or the solution thereof. A method for producing a paste according to paragraph 17, wherein an aqueous solution of glycerin is used as a solution for the organic compound described in paragraph 17, and a paste is produced according to the method described in paragraph 17.

That is, 1,5-pentanediol belongs to a divalent alcohol, has a viscosity of 135 mPa · s at 20 ° C, is easily soluble in water, has a melting point of -16 ° C, and has a boiling point of 238 ° C. .. Further, it is a general-purpose organic compound used as a raw material for polyurethane for paints, polyester resin, and polycarbonate diol resin.
On the other hand, glycerin is a trihydric alcohol, has a viscosity of 1499 mPa · s at 20 ° C, is easily soluble in water, has a melting point of 20 ° C, and has a boiling point of 290 ° C. Also, pharmaceuticals, cosmetics, toiletries, foods, monoglycerides, capsules, alkyd resins, polyurethanes, cellophane, films, shavings, mouthwashes, inks, fragrances, tobacco, tobacco filters, explosives, antifreeze, soap, textiles, paper, It is a general-purpose organic compound widely used as a raw material for solvents and condensers.
By the way, in the solution of the organic compound constituting the paste described in paragraph 17, as described in paragraph 18, the solution adsorbs to the powder with an adsorptive force according to the viscosity of the solution, and the solution is also adsorbed. The planes of the powder overlap each other and are adsorbed. Further, as described in paragraph 18, the volume ratio of the organic compound solution to the paste is more than 3 times the volume ratio of the powder collection to the paste, and 3 times the thickness of the flat surface of the powder. The paste has fluidity as a liquid when the planes of the powder are overlapped with each other through a solution of an organic compound having a thick thickness. Therefore, the paste described in paragraph 17 is composed of a collection of powders in which the planes of the powders are overlapped with each other via a solution of an organic compound having a thickness of more than 3 times the thickness of the powders.
On the other hand, the thickness, particle size and density of the flake-like, scaly or flat powder made of the metal or alloy described in paragraph 17 vary depending on the material of the metal or alloy. Since the thickness of the powder is determined by the ease of processing flakes, scales, or flats, powders with high hardness are difficult to process and thick. The thickest powder is the flat powder made of the reduced iron powder described in paragraph 20, and the thickness of the flat powder is as thick as 10-20 μm. On the other hand, in the four types of alloys other than iron described in paragraph 20, the composition of the alloy was changed to reduce the hardness in order to facilitate the flattening treatment, and the thickness of the flat powder was in the range of 1-1.5 μm. Go inside. Further, the metal flake powder or scale powder described in paragraph 26 has a low hardness, and the thickness of the powder is as thin as 0.15-1.0 μm. Further, the particle size of the powder depends on the structure and shape of the atomized particles or the reduced particles before being processed into the powder, and depends on the conditions for processing the particles into the powder. Therefore, even if the powder material is the same, the particle size varies depending on the powder used.
By the way, in the coating film applied using the paste described in paragraph 17, the planes of the powder overlap each other via a solution of an organic compound having a thickness three times the thickness of the powder, and the powder is formed. It is assumed that four layers are laminated to form a coating film. When the thickness of the powder is 15 μm, the thickness of the coating film is 285 μm. On the other hand, when the thickness of the powder is 0.5 μm, the thickness of the coating film is only 9.5 μm. On the other hand, since the thickness of the solution of the organic compound is thicker than three times the thickness of the powder, the thickness of the coating film of the solution of the organic compound changes depending on the thickness of the powder. Further, when the thickness of the powder made of different materials is the same 1 μm, but the density of the powder is different, the weight of the powder changes. Further, although the thickness of the powder made of the same material is the same 1 μm, if the particle size of the powder is different, the weight of the powder changes. For this reason, the relatively heavy powder relatively increases the viscosity of the solution of the organic compound, relatively increases the adsorptive power that the solution adsorbs to the powder, and also the powder via the solution. It is necessary to relatively increase the adsorption force that the planes of the body overlap and adsorb. Therefore, as described in paragraph 18, it is necessary to set the viscosity of the solution of the organic compound constituting the paste according to the average thickness of the powder and the average particle size and density.
According to the results of the experiment, it was found that the solution of the organic compound needs to have a viscosity of 1200 mPa · s in order to form a coating film having a thickness of 300 μm. Therefore, in order to form a coating film of 10 μm, the solution of the organic compound has a viscosity of 40 mPa · s. In this way, the viscosity of the solution of the organic compound is changed according to the thickness of the coating film to be formed.
On the other hand, divalent alcohol is soluble in water and has a higher viscosity than glycols. Among divalent alcohols, 1,5-pentanediol has the highest viscosity among divalent alcohols, has a viscosity of 135 mPa · s at 20 ° C, is easily soluble in water, and has a melting point of -16 ° C. , The boiling point is as low as 238 ° C. Therefore, the viscosity of the aqueous solution of 1,5-pentanediol can be adjusted within the range of 10-120 mPa · s. Glycerin, which is a trihydric alcohol, has a high viscosity of 1499 mPa · s at 20 ° C, is easily dissolved in water, has a melting point of 20 ° C, and has a low boiling point of 290 ° C. Therefore, the viscosity of the aqueous solution of glycerin can be adjusted within the range of 120-1350 mPa · s. As a result, the viscosity of the solution of the organic compound can be adjusted in a wide range of 10-1350 mPa · s, and the thickness of the coating film can be formed in a wide range of 2.5-338 μm. As a result, even if the thickness of the powder has a deviation of 0.15-20 μm, a coating film in which three or more layers of powder are laminated via a solution of an organic compound can be formed. Therefore, an aqueous solution of 1,5-pentanediol and an aqueous solution of glycerin are used as the dissolution liquids of the organic compounds constituting the paste described in paragraph 17, depending on the thickness and particle size of the powder and the density of the powder. , I decided to adjust the concentration of the aqueous solution. Thereby, the aqueous solution of 1,5-pentanediol and the aqueous solution of glycerin can be used as a solution in which the organic compound described in paragraph 17 is dissolved in a solvent.

It is explanatory drawing which shows typically the side surface of the sheet which consists of the group of the flat iron powder which flat iron powder is directly bonded to each other.

Example 1
In this embodiment, as the soft magnetic flat powder, flat iron powder obtained by flattening the reduced iron powder is used, and the flat iron powder is composed of a collection of the flat iron powder in which the flat surfaces of the flat iron powder are overlapped with each other via an aqueous solution of glycerin. Make the paste in a container. As the flat iron powder, the flat iron powder MG150D manufactured by JFE Steel Corporation was used. This flat iron powder has a large average particle size of 100 μm, but a thickness of 10-20 μm. This is because the particles of the reduced iron powder are relatively large, but the Vickers hardness of the reduced iron powder is as high as 160-200 HV, and it is difficult to flatten.
First, a solution was prepared by dissolving glycerin (for example, a product of Sakamoto Yakuhin Kogyo Co., Ltd.) in distilled water at a volume ratio of 60%. The viscosity of the aqueous solution of glycerin is 900 mPa · s. 100 cc of an aqueous solution of glycerin was filled in a container of 10 cm × 10 cm × 3 cm (depth), and 40 g of flat iron powder was put into the container. After that, 20 kHz ultrasonic vibration was applied to the aqueous solution of glycerin in the container by an ultrasonic homogenizer device (for example, LUH300 product of Yamato Scientific Co., Ltd.) for 2 minutes. Further, the ultrasonic homogenizer device was taken out of the container, and vibration acceleration in three directions consisting of 0.2 G was repeatedly applied to the container, and the flat iron powders in which the flat surfaces of the flat iron powders overlapped with each other via an aqueous solution of glycerin were placed in the container. I made a paste consisting of a collection of.

Example 2
In this embodiment, the paste prepared in Example 1 is used to bond the overlapping portions of the flat iron powders to each other by frictional heat to form a sheet composed of a collection of flat iron powders to which the flat iron powders are joined. do.
The paste prepared in Example 1 was uniformly applied to a FEP resin plate having a thickness of 10 cm × 10 cm × 1 cm (thickness) to form a coating film. After that, the temperature of the FEP resin plate was raised to 290 ° C., which is the boiling point of glycerin, and the aqueous solution of glycerin was vaporized from the coating film. After that, a FEP resin plate material having a thickness of 10 cm × 10 cm × 5 mm (thickness) is placed on the coating film, and further.
A weight of 120 kg was placed on the FEP resin plate. After that, the weight and the FEP resin plate material are removed from the coating film, and an impact acceleration of 0.5 G is repeatedly applied to the side surface of the FEP resin plate material on which the coating film is formed, and a sample is pulled from the FEP resin plate material. I peeled it off. Five sheets were created in this way.
Next, the surface and sides of the sample were observed with an electron microscope. As the electron microscope, an extremely low acceleration voltage SEM manufactured by JFE Techno Research Co., Ltd. was used. This device is capable of observing the surface with an extremely low acceleration voltage from 100 V, and has the feature that the surface of the sample can be directly observed without forming a conductive film on the sample.
First, the secondary electron beam between 900 and 1000 V of the backscattered electron beam was taken out and image processing was performed. Three flat surfaces of flat powder having a size of 10-20 μm were stacked to form a 10 cm × 10 cm sheet having a thickness of about 45 μm. Further, the energy between 900 and 1000 V of the reflected electron beam was extracted and image processing was performed, and the material was observed by the shading of the image. No shading was observed, indicating that it was formed from a single element. Next, the energy of the characteristic X-ray and its intensity were image-processed and the elements were analyzed. It turned out to be an iron atom. Therefore, the flat iron powders were directly bonded to each other, and a collection of flat iron powders formed a sheet. Since the depth of the skin of the electromagnetic wave of the reduced iron powder at 100 kHz is 50 μm, the sheet having a thickness of about 45 μm uses a flat powder made of a small amount of the reduced iron powder, and the electromagnetic wave is effectively around 100 kHz. Absorbs the noise of. FIG. 1 schematically shows the side surface of a sheet composed of a collection of flat iron powder in which flat iron powder is directly bonded to each other. 1 is flat iron powder.
Furthermore, the magnetic shielding performance of the prepared sheet was evaluated. For comparison, a cold-rolled steel sheet with a thickness of 45 μm was used. A shield box having a rectangular parallelepiped shape with a side of 100 mm was made of both a sheet and a cold-rolled steel plate. The shield box is placed in the Helmholtz coil placed in the magnetic shield room, and the external magnetic field generated from the Helmholtz coil and the internal magnetic field at the center position of the shield box are measured to formulate the magnetic shield performance S. It was evaluated by 2. The magnetic sensor for measuring the magnetic field was installed in the shield box through the hole provided in the shield box. The sample had a magnetic shield performance S of 7 dB, and had a good magnetic shield performance of about 3 dB as compared with the cold-rolled steel sheet. As a result, it was found that the prepared sheet can obtain an excellent magnetic shielding effect.
(Number 2)
S = 20log ((external magnetic field) / (internal magnetic field))
Next, the performance of absorbing the electromagnetic noise of the sheet was evaluated. Align the length of the sheet with the length of the microstrip line on the board on which the microstrip line with a length of 140 mm, width of 30 mm and characteristic impedance adjusted to 50Ω is installed, so that the centers of the sheets match. A sheet was placed to make a magnetic sheet that absorbs noise. After that, the S parameter was measured using a network analyzer (product N5230A of Agilent Technologies, Ltd.) connected to the microstrip line. From the S parameter S ₁₁ due to reflection and the S parameter S ₁₂ due to transmission, the transmission loss in the microstrip line is the absorption amount of electromagnetic waves according to the following mathematical formula 3.
The measurement results showed that the absorption amount was 12% at 100 kHz, the absorption amount was 24% at 800 kHz, and the absorption amount was 13% at 10 MHz. The sheet had an absorption amount of 12% or more in the frequency band of 100 kHz to 10 MHz.
(Number 3)
Reflection amount (dB) = 20log | S ₁₁ |
Permeation amount (dB) = 20log | S ₁₂ |
Absorption amount (%) = (1- | S ₁₁ | ^2- | S ₁₂ | ² ) x 100

Example 3
In this embodiment, flat permalloy powder is used as the soft magnetic flat powder, and a paste consisting of a collection of the flat permalloy powder in which the flat surfaces of the flat permalloy powder are overlapped with each other via an aqueous solution of 1,5-pentanediol is placed in a container. Manufactured in. As the flat permalloy powder, a permalloy flat powder containing 50% nickel (for example, a product developed by Sanyo Special Steel) was used. The flat powder has a flattening ratio of 38 and an average particle size of 14 μm. Further, the imaginary part of the complex magnetic permeability rises sharply from around 100 MHz, has a peak value of 8.8 at 3.3 GHz, decreases from around 4 GHz, and has a value of 3.5 at 10 GHz. Therefore, in the frequency band of 1-8 GHz, the imaginary part of the complex magnetic permeability has a value of 5 or more. On the other hand, in the DC magnetic field, the initial relative permeability is 1 × ^{10 4} , and the maximum relative permeability is 1.4 × 105, which are large values.
First, a solution was prepared by dissolving 1,5-pentanediol (for example, a product of Fuji Film Wako Pure Chemical Industries, Ltd.) in distilled water at a volume ratio of 64%. The viscosity of the aqueous solution of 1,5-pentanediol is 86 mPa · s. 100 cc of an aqueous solution of 1,5-pentanediol was filled in a container of 10 cm × 10 cm × 3 cm (depth), and 20 g of permalloy flat powder was put into the container. Then, 20 kHz ultrasonic vibration was applied to the aqueous solution of 1,5-pentanediol in the container by an ultrasonic homogenizer for 2 minutes. Furthermore, the ultrasonic homogenizer device is taken out of the container, and vibration acceleration in three directions consisting of 0.2 G is repeatedly applied to the container, and the flat surfaces of the permalloy flat powder are placed in the container via an aqueous solution of 1,5-pentanediol. A paste consisting of a collection of overlapping permalloy flat powders was made.

Example 4
In this embodiment, the paste prepared in Example 3 is used to bond the overlapping portions of the flat powders of Permalloy with frictional heat, and a sheet composed of a collection of the flat powders of Permalloy bonded to each other. To form.
The paste prepared in Example 3 was uniformly applied to a FEP resin plate having a thickness of 10 cm × 10 cm × 1 cm (thickness) to form a coating film. After that, the temperature of the FEP resin plate was raised to 238 ° C., which is the boiling point of 1,5-pentanediol, and the aqueous solution of 1,5-pentanediol was vaporized from the coating film. After that, a FEP resin plate having a thickness of 10 cm × 10 cm × 5 mm (thickness) was placed on the coating film, and a weight of 80 kg was placed on the FEP resin plate. After that, the weight and the FEP resin plate material are removed from the coating film, and an impact acceleration of 0.5 G is repeatedly applied to the side surface of the FEP resin plate material on which the coating film is formed, and a sample is pulled from the FEP resin plate material. I peeled it off. Five sheets were created in this way.
Next, the surface and the side surface of the sheet were observed with an electron microscope in the same manner as in Example 2. A substance having a thickness of 0.4-0.5 μm was laminated in 10 layers. This material is permalloy because it was composed of nickel and iron atoms. Since the depth of the epidermis of permalloy at 1 GHz is 5.0 μm, the sheet having a thickness of 4-5 μm uses a small amount of flat powder made of permalloy to effectively reduce the noise of electromagnetic waves near 1 GHz. Absorb.
Further, the magnetic shielding performance of the sheet was evaluated by the same method as in Example 2. For comparison, a 5 μm thick sheet of permalloy with 47% nickel was used. Similar to Example 2, a rectangular parallelepiped shield box having a side of 100 mm was created for each of the sheet and the permalloy sheet. The sample had a magnetic shielding performance S of 40 dB, and had a good magnetic shield performance of about 5 dB as compared with the 47Ni permalloy sheet. As a result, the sample provides an excellent magnetic shielding effect.
Next, the performance of the sheet to absorb electromagnetic noise was evaluated by the same method as in Example 2. The absorption amount was 8% at 1 GHz, the absorption amount was 10% at 3 GHz, and the absorption amount was 8% at 6.8 GHz. Therefore, the sample had an absorption amount of 8% or more in the frequency band of 1 GHz to 7 GHz. However, the amount of electromagnetic waves absorbed is small. This is because the average particle size of the permalloy flat powder is small and the flatness is low.

Example 5
In this embodiment, flat sendust powder is used as the soft magnetic flat powder, and a paste consisting of a collection of the flat sendust in which the flat surfaces of the flat sendust powder are overlapped with each other via an aqueous solution of glycerin is produced in a container.
Sendust's flat powder is a product called high magnetic permeability type A of Sanyo Special Steel, which has a large average particle size of 50 μm or less, a thickness of about 1 μm, and a flatness close to 50. Compared to conventional sendust, this flat powder has a small amount of nickel added, the amount of silicon added is reduced, flattening is facilitated, and the particle size of the flat powder is increased, and the complex magnetic permeability is increased. The characteristics have been greatly improved. The imaginary part of the complex magnetic permeability has a value of 60 or more in the frequency band of 10-70 MHz and a value of 30 or more in the frequency band of 3-100 MHz. Compared with the permalloy flat powder used in Example 3, since the flat powder has a large particle size, the flatness is large, and the frequency band in which the value of the imaginary portion of the complex magnetic permeability exceeds 10 times extends to 3-100 MHz. Further, the real part of the complex magnetic permeability has a large value of 200 at 1-3 MHz. Therefore, it is effective as a noise countermeasure for electromagnetic waves in a frequency band of 3 MHz or higher. On the other hand, the magnetic permeability in the DC magnetic field is two orders of magnitude smaller than that of the permalloy used in Example 3, so that the effect of the magnetic shield is low. The skin depth of the flat sendust powder at 3 MHz is 20 μm.
First, a solution was prepared by dissolving the glycerin used in Example 1 in distilled water at a volume ratio of 22%. The viscosity of the aqueous solution of glycerin is 330 mPa · s. 100 cc of an aqueous solution of glycerin was filled in a container of 10 cm × 10 cm × 3 cm (depth), and 40 g of flat powder of Sendust was put into the container. After that, 20 kHz ultrasonic vibration was applied to the aqueous solution of glycerin in the container by an ultrasonic homogenizer for 2 minutes. Further, the ultrasonic homogenizer device was taken out of the container, vibration acceleration in three directions consisting of 0.2 G was repeatedly applied to the container, and the flat surfaces of the flat powder of sendust overlapped with each other via the aqueous solution of glycerin in the container. A paste consisting of a collection of flat powder was prepared.

Example 6
In this embodiment, the paste prepared in Example 5 is used, and the portions where the flat powders of Sendust overlap each other are joined by frictional heat, and the sheet consisting of a collection of the flat powders of Sendust joined by the flat surfaces is joined. To form.
The paste prepared in Example 5 was uniformly applied to a FEP resin plate having a thickness of 10 cm × 10 cm × 1 cm (thickness) to form a coating film. After that, the temperature of the FEP resin plate was raised to 290 ° C., which is the boiling point of glycerin, and the aqueous solution of glycerin was vaporized from the coating film. After that, a FEP resin plate having a thickness of 10 cm × 10 cm × 5 mm (thickness) was placed on the coating film, and a weight of 100 kg was placed on the FEP resin plate. After that, the weight and the FEP resin plate material are removed from the coating film, and an impact acceleration of 0.5 G is repeatedly applied to the side surface of the FEP resin plate material on which the coating film is formed, and a sample is pulled from the FEP resin plate material. I peeled it off. Five sheets were created in this way.
Next, the surface and the side surface of the sheet were observed with an electron microscope in the same manner as in Example 2. A substance having a thickness of 1 μm was laminated in 20 layers. This substance is closer to super-sendust than sendust because iron atoms occupy the majority, followed by silicon atoms, followed by aluminum atoms, and a few nickel atoms are observed. Since the skin depth of the flat Sendust powder at 3 MHz is 20 μm, the sheet having a thickness of 20 μm effectively absorbs the noise of the electromagnetic wave near 3 MHz by using a small amount of the flat powder of Sendust.
Further, the performance of the prepared sheet to absorb electromagnetic noise was evaluated by the same method as in Example 2. The absorption amount was 28% at 3 MHz, the absorption amount was 38% at 10 MHz, the absorption amount was 42% at 20 MHz, the absorption amount was 38% at 50 MHz, and the absorption amount was 28% at 100 MHz. Therefore, the prepared sheet had an absorption amount of 28% or more in the frequency band of 3-100 MHz. Compared with Example 4, the amount of electromagnetic wave absorption was significantly increased. This is because the grain size of the sendust flat powder is larger and the flattening ratio is larger than that of the permalloy flat powder.

Example 7
In this embodiment, a flat powder composed of three types of alloys in which the imaginary part of the complex magnetic permeability has peak values in different frequency bands is used, and the flat surfaces of the three types of flat powder are 1,5-pentanediol. A paste consisting of a collection of the flat powders overlapped with each other via an aqueous solution is produced in a container.
As the flat powders of the three types of alloys, the flat powders of silicon steel having 3% silicon and the flat powders of electromagnetic stainless steel were added to the flat powders of permalloy used in Example 3.
A flat powder made of silicon steel containing 3% silicon (for example, a product developed by Sanyo Special Steel) has a flatness of 34 and an average particle size of 9 μm. Further, the imaginary part of the complex magnetic permeability has a required size in the high frequency band in contrast to the flat powder of Permalloy of Example 2. That is, it gradually increases from around 10 MHz, has a value of 2.3 at 1 GHz, intersects with the value of the imaginary part of Permalloy's complex magnetic permeability at 4.7 GHz, and shows a peak value of 8.7 at 5.9 GHz. , It gradually decreases from around 6.3 GHz, has a value of 5.9 even at 10 GHz, and has a value of 3.7 at 12 GHz. Therefore, at 4.7 GHz or higher, the value of the imaginary part of the complex magnetic permeability is larger than that of the flat powder of permalloy.
A flat powder made of electromagnetic stainless steel obtained by adding 7% chromium, 1% silicon and 1.6% aluminum to iron (for example, a product developed by Sanyo Special Steel) has a flatness of 29 and an average particle size of 29. It is 12 μm. In addition, the imaginary part of complex magnetic permeability increases sharply from around 10 MHz and has a value of 3.4 at 1 GHz, and at 4.2 GHz, silicon intersects with the imaginary part of 3% silicon steel, and at 4.8 GHz. It shows a peak value of 7.5, gradually decreases from around 5.5 GHz, has a value of 4.8 even at 10 GHz, and has a value of 3.1 at 12 GHz.
Therefore, a sheet in which the flat powders of the three types of flat powders are randomly superposed with each other using three types of flat powders consisting of permalloy flat powder, silicon steel flat powder having 3% silicon, and electromagnetic stainless steel flat powder. When, the characteristic of the imaginary part of the complex magnetic permeability of the sheet becomes the characteristic that the characteristic of the imaginary part of the complex magnetic permeability of the three types of flat powder is added, and the electromagnetic noise in the middle frequency band up to 2-8 GHz. Performance to absorb is improved. In particular, electromagnetic noise in the frequency band from 3.3 GHz where the imaginary part of the complex magnetic permeability of Permalloy shows the peak value to 4.8 GHz where the imaginary part of the complex magnetic permeability of silicon steel with 3% silicon shows the peak value. The absorption performance is improved.
First, a solution was prepared by dissolving 1,5-pentanediol in distilled water at a volume ratio of 64%. The viscosity of the aqueous solution of 1,5-pentanediol is 86 mPa · s. A container of 10 cm × 10 cm × 3 cm (depth) was filled with 100 cc of an aqueous solution of 1,5-pentanediol. Next, 8 g of permalloy flat powder, 7 g of silicon steel flat powder, and 15 g of electromagnetic stainless steel flat powder were put into a container, and the aqueous solution of 1,5-pentanediol in the container was stirred. Then, 20 kHz ultrasonic vibration was applied to the aqueous solution of 1,5-pentanediol in the container by an ultrasonic homogenizer for 2 minutes. Furthermore, the ultrasonic homogenizer device is taken out of the container, and vibration acceleration in three directions consisting of 0.2 G is repeatedly applied to the container. A paste consisting of a collection of three types of flat powders overlapped with each other via an aqueous solution was prepared.

Example 8
In this example, using the paste prepared in Example 7, the portions where the flat surfaces of the flat powders made of three types of alloys overlap each other are bonded by frictional heat, and the flat powders of the three types bonded to each other are bonded by frictional heat. Form a sheet consisting of a collection of.
The paste prepared in Example 7 was uniformly applied to a FEP resin plate having a thickness of 10 cm × 10 cm × 1 cm (thickness) to form a coating film. After that, the temperature of the FEP resin plate was raised to 238 ° C., which is the boiling point of 1,5-pentanediol, and the aqueous solution of 1,5-pentanediol was vaporized from the coating film. After that, a FEP resin plate having a thickness of 10 cm × 10 cm × 5 mm (thickness) was placed on the coating film, and a weight of 100 kg was placed on the FEP resin plate. After that, the weight and the FEP resin plate material are removed from the coating film, and an impact acceleration of 0.5 G is repeatedly applied to the side surface of the FEP resin plate material on which the coating film is formed, and a sample is pulled from the FEP resin plate material. I peeled it off. Five sheets were created in this way.
Next, the surface and the side surface of the sheet were observed with an electron microscope in the same manner as in Example 2. A substance having a thickness of 0.4-0.6 μm was laminated in 10 layers.
Further, the performance of the prepared sheet to absorb electromagnetic noise was evaluated by the same method as in Example 2. The absorption amount was 8% at 1 GHz, the absorption amount was 10% at 3.3 GHz, the absorption amount was 9% at 4.7 GHz, the absorption amount was 10% at 5.9 GHz, and the absorption amount was 8% at 10 GHz. As a result, the absorption amount was 8% or more in a wide frequency band of 1-10 GHz. However, the amount of electromagnetic waves absorbed is small. This is because the average particle size of the three types of alloys is smaller and the flatness is lower than that of the sendust flat powder used in Example 6.
The example of combining soft magnetic flat powder made of a plurality of types of alloys is not limited to Example 7. In other words, when the flat powders are combined so that the imaginary part of the complex magnetic permeability has a constant value in a wide frequency band, the collection of flat powders in which the flat surfaces are overlapped and bonded is the complex magnetic permeability of each flat powder. The characteristics of the imaginary part of the complex magnetic permeability to which the characteristics of the imaginary part of the above are added are shown, and as a result, a sheet that absorbs electromagnetic noise can be realized in a wide frequency band.

Example 9
In this embodiment, flake copper powder is used to produce a paste consisting of a collection of the flake powder in which the planes of the flake copper powder are overlapped with each other via an aqueous solution of 1,5-pentanediol in a container. As the flake copper powder, the product number MS-800 manufactured by Fukuda Metal Foil Powder Industry Co., Ltd. was used. The particle size distribution of this flake copper powder is such that flake powder larger than 75 μm accounts for more than 4%, flake powder larger than 45 μm accounts for more than 25%, and flake powder smaller than 45 μm accounts for more than 75%. Since the thickness is around 0.5 μm, the aspect ratio is large. In addition, the apparent density is as low as 0.6-1.0 g / cm ³ .
First, a solution was prepared by dissolving 1,5-pentanediol in distilled water at a volume ratio of 28%. The viscosity of the aqueous solution of 1,5-pentanediol is 38 mPa · s. 100 cc of an aqueous solution of 1,5-pentanediol was filled in a container of 10 cm × 10 cm × 3 cm (depth), and 10 g of flat powder of flake copper powder was put into the container. Then, 20 kHz ultrasonic vibration was applied to the aqueous solution of 1,5-pentanediol in the container by an ultrasonic homogenizer for 2 minutes. Furthermore, the ultrasonic homogenizer device was taken out of the container, and vibration acceleration in three directions consisting of 0.2 G was repeatedly applied to the container, and the planes of the flake copper powder overlapped with each other in the container via an aqueous solution of 1,5-pentanediol. A paste consisting of a collection of flake copper powder was created.

Example 10
In this embodiment, using the paste prepared in Example 9, the portions where the planes of the flake copper powder overlap each other are joined by frictional heat to form a sheet composed of a collection of flake copper powder in which the planes are joined.
The paste prepared in Example 9 was uniformly applied to a FEP resin plate having a thickness of 10 cm × 10 cm × 1 cm (thickness) to form a coating film. After that, the temperature of the FEP resin plate was raised to 238 ° C., which is the boiling point of 1,5-pentanediol, and the aqueous solution of 1,5-pentanediol was vaporized from the coating film. After that, a FEP resin plate having a thickness of 10 cm × 10 cm × 5 mm (thickness) was placed on the coating film, and a weight of 50 kg was placed on the FEP resin plate. After that, the weight and the FEP resin plate material are removed from the coating film, and an impact acceleration of 0.4 G is repeatedly applied to the side surface of the FEP resin plate material on which the coating film is formed, and a sample is pulled from the FEP resin plate material. I peeled it off. Five sheets were created in this way.
Next, the surface and the side surface of the sheet were observed with an electron microscope in the same manner as in Example 2. A substance having a thickness of about 0.5 μm was laminated in four layers. This substance is a copper powder because it was composed only of copper atoms.
Further, a DC resistance meter (for example, a DC resistance meter model 356H manufactured by Tsuruga Electric Co., Ltd.) was used to measure the electrical resistance of the sheet. Bite the terminals at four points on the sheet, apply direct current to the sheet in different directions, measure the voltage twice with the two inner terminals, and measure the difference between these two voltage values with the two outer terminals. The resistance value obtained by dividing by the current value showed a volume resistivity close to that of copper.
In addition, the coefficient of friction of a plurality of surfaces of a plurality of sheets was measured by a measuring device (a friction coefficient measuring device consisting of a tabletop precision universal tester Autograph AGS-X manufactured by Shimadzu Corporation). The coefficient of static friction was 0.15 ± 0.05 and the coefficient of dynamic friction was 0.12 ± 0.03. Both friction coefficients are small.
Therefore, the created sheet can be used as a sheet having both conductivity and thermal conductivity, a sheet having both lubricity and conductivity, and a sheet for shielding electromagnetic waves.

The five examples relating to the paste in the present invention have been described, and the five examples relating to the sheet prepared by using the paste have been described, but the examples are not limited thereto. This is because the method for producing a paste consists of three processes of preparing a mixture consisting of a solution of an organic compound and a collection of powders, operating a homogenizer device in the mixture, and repeatedly applying vibration acceleration in three directions to the container. .. Therefore, there are no restrictions on the material, shape, and particle size distribution of the powder used. Therefore, the paste examples are not limited to the five examples. Further, in the method of creating a sheet using a paste, since the paste is applied to the base material to form a coating film, there are no restrictions on the area and shape of the coating film. Furthermore, by vaporizing the solution of the organic compound from the coating film and further applying compressive stress, the overlapping planes are joined by frictional heat to form a sheet consisting of a collection of powders, so that the powder has a flat surface. A sheet can be formed with versatility for the body. Therefore, the examples of the sheet are not limited to the five examples.

1 Flat iron powder

Claims (7)

A method for producing a paste consisting of a collection of flakes, scaly or flat powders made of a metal or an alloy in which planes of the powders are overlapped with each other via a solution of an organic compound is described.
The viscosity of the solution of the organic compound in which the organic compound is dissolved with a solvent is set from the average thickness, the average particle size and the density of the flake-like, scaly or flat powder made of a metal or an alloy, and the like. The volume of the solution of the organic compound having viscosity is weighed so that the volume is more than three times the volume occupied by the collection of the powders to prepare the solution of the organic compound, and the solution of the organic compound is combined with the solution of the organic compound. The container is filled with the aggregate of the powder, and then the homogenizer device is operated in the container, and the impact is repeatedly applied to the aggregate of the powder via the solution of the organic compound to form the aggregate of the powder. , The powder is separated into individual powders via the solution of the organic compound, the powder is covered with the solution of the organic compound, and then the homogenizer device is taken out from the container, and further, the container is further removed. A paste consisting of a collection of the powders in which the planes of the powders are overlapped with each other via the solution of the organic compound is produced in the container by repeatedly applying vibration accelerations in three directions of front-back, left-right, and up-down. A method for producing a paste consisting of a collection of flakes, scaly or flat powders made of a metal or an alloy in which planes of the powder are overlapped with each other via a solution of an organic compound. In the method for producing the paste according to claim 1, the flat powder made of the metal or alloy according to claim 1 is made of any one of iron, permalloy, silicon steel, sentust or electromagnetic stainless steel. It is a soft magnetic flat powder, and the soft magnetic flat powder is used as a flat powder made of the metal or alloy according to claim 1, and a paste is produced according to the method for producing a paste according to claim 1. The method for producing the paste according to claim 1. The method for producing the paste according to claim 2 is that the soft magnetic flat powder according to claim 2 is a flat powder composed of a plurality of types of alloys excluding the flat powder of reduced iron powder, and the plurality of types of alloys. The frequency characteristics of the imaginary part of the complex magnetic permeability of the flat powder are different from each other, and the frequency characteristics of the imaginary part of the complex magnetic permeability of each flat powder complement each other in different frequency ranges. The flat powder made of a plurality of types of alloys having the frequency characteristics of the imaginary portion of the complex magnetic permeability is used as the soft magnetic flat powder according to claim 2, and according to the method according to claim 2. The method for producing a paste according to claim 2, wherein the paste is produced. A method of joining the flat surfaces of soft magnetic flat powders to each other using the paste produced by the production method according to claim 2 to form a sheet composed of a collection of the soft magnetic flat powders, or claim 3. The method of joining the flat surfaces of the flat powders of a plurality of types of alloys to each other using the paste produced by the production method described in the above method to form a sheet composed of a collection of the flat powders of the plurality of types of alloys is described.
The paste produced by the method according to claim 2 or 3 is applied to a substrate to form a coating film composed of the paste on the substrate, and then a solution of the organic compound is applied from the coating film. It is vaporized, whereby a film consisting of a collection of the flat powders in which the flat powders of the soft magnetic powder are overlapped is formed on the base material, or the flat powders of a plurality of types of alloys are overlapped with each other. A film composed of a collection of flat powders of the plurality of types of alloys is formed on the base material, and then the flat surface above the film is evenly compressed, whereby the flat surfaces of the soft magnetic flat powders are brought together. Friction heat is generated at the overlapping portions, and the overlapping flat powders are bonded to each other by the friction heat, and a sheet composed of a collection of the bonded soft magnetic flat powders is formed on the base material, or the plurality. Friction heat is generated at the portion where the flat powders of the different types of alloys overlap each other, and the overlapping flat powders are joined by the frictional heat, and the sheet is composed of a collection of the flat powders of the plurality of types of the bonded pieces. Is formed on the base material, and then the side surface of the base material is repeatedly subjected to impact acceleration, the sheet formed on the base material is peeled off from the base material, and the sheet is taken out. A method of joining flat surfaces of soft magnetic flat powders to each other using a paste produced by the production method described to form a sheet composed of a collection of the soft magnetic flat powders, or the production method according to claim 3. A method of joining flat surfaces of flat powders of a plurality of types of alloys to each other using the paste produced in the above method to form a sheet composed of a collection of flat powders of the plurality of types of alloys. In the method for producing the paste according to claim 1, the flake-like or scaly powder made of the metal or alloy according to claim 1 is made of any material of silver, copper, brass, nickel, zinc or aluminum. It is a flake powder or scale powder composed of, and the flake powder or scale powder is used as a flake-like or scale-like powder made of the metal or alloy according to claim 1 to produce the paste according to claim 1. The method for producing a paste according to claim 1, wherein the paste is produced according to the method. Using the paste produced by the method according to claim 5, the portions where the planes of the metal flake powder or the scale powder overlap are joined by frictional heat, and the metal flake powder or the scale powder to which the planes are joined are collected. The method of forming a sheet consisting of
The paste produced by the method according to claim 5 is applied to a base material to form a coating film composed of the paste on the base material, and then the solution of the organic compound is vaporized from the coating film to form a metal. A coating consisting of a collection of the flake powder or the scale powder on which the planes of the flake powder or the scale powder are overlapped is formed on the substrate, and then the upper plane of the coating is evenly compressed. Friction heat is generated at the portion where the planes of the flake powder or the scale powder overlap each other, and the friction heat joins the planes of the overlapped flake powder or the scale powder to each other, and the flake powder or the scales to which the planes are joined are joined. A sheet composed of a collection of powders is formed on the base material, and then impact acceleration is repeatedly applied to the side surface of the base material to peel off the sheet formed on the base material from the base material, and the sheet is released. Using the paste produced by the method according to claim 5, the metal flake powder or scale powder is bonded to the portion where the planes of the metal flake powder or scale powder overlap with each other by frictional heat, and the metal flake powder or scale powder to which the planes are bonded is bonded. A method of forming a sheet consisting of a collection of powders. In the method for producing the paste according to claim 1, the solution of the organic compound according to claim 1 is an aqueous solution of 1,5-pentanediol or an aqueous solution of glycerin, and the aqueous solution of 1,5-pentanediol. The method for producing a paste according to claim 1, wherein the aqueous solution of glycerin is used as a solution for the organic compound according to claim 1 to produce a paste according to the method according to claim 1.

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