Method for continuously manufacturing sheet formed of aggregation of flat powder in which flat surfaces of flat powder are joined to each other by friction welding

Abstract

To provide a method for continuously manufacturing a sheet composed of an aggregate of flat powder in which flat surfaces of the flat powder are joined to each other by friction welding.SOLUTION: Preparing a suspension in which flat surfaces of a flat powder overlap each other via a liquid, continuously attaching the suspension to a sheet, continuously joining an aggregate of the flat powder in which the flat surfaces overlap and are joined to each other to a surface of the sheet, and continuously removing the sheet from the aggregate of the flat powder; Continuously forming a new sheet formed of an aggregate of the flat powder, continuously attaching a suspension in which flat surfaces of the flat powder overlap each other via alcohol to one surface of a synthetic resin film, and continuously compressing the suspension to continuously produce a sheet in which the aggregate of the flat powder bonded by friction welding is bonded to one surface of the synthetic resin film; A film of a synthetic resin is continuously dissolved with a solvent to continuously produce a new sheet comprising an aggregate of bonded flat powder, and the adhered solvent is continuously vaporized to produce a sheet comprising an aggregate of bonded flat powder.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a method for continuously producing a sheet made of a collection of flat powder in which the flat surfaces of the flat powder are joined together by friction welding, through a process consisting of the following eight steps. In the first step, a suspension of flat powder particles dispersed in alcohol is applied to one side of a synthetic resin film. A container is prepared in which a first work roll consisting of two cylinders is placed in the center of the container so that the two work rolls are adjacent to each other in the vertical direction, and the container is then placed on the vibration table of a vibrator. In the second step, the container is filled with a collection of flat powder, and an amount of alcohol having a viscosity of 6-10 mPa·sec at 20°C and a boiling point lower than 200°C is also filled into the container so that a portion of the work roll below the first work roll is constantly immersed in the alcohol.The vibrator is then operated to repeatedly apply vertical, horizontal, and front-to-back vibrations to the container, creating a suspension in the container in which the flat surfaces of the flat powder overlap with each other via the alcohol. In the third step, the synthetic resin film is continuously drawn out from the wound roll at a speed equivalent to the peripheral speed of the first work roll, the leading edge of the synthetic resin film is inserted into the gap between the two work rolls that rotate in opposite directions, the suspension is applied to one side of the synthetic resin film, and the synthetic resin film with the suspension applied thereto is continuously fed out from the gap between the two work rolls at a speed equivalent to the peripheral speed of the first work roll. In the fourth step, a gap between two work rolls is set to a thickness thinner than the sum of the thickness of the aggregate of flat powder whose flat surfaces are joined together and the thickness of the synthetic resin film, and a multi-stage rolling mill is prepared in which the two work rolls rotate in opposite directions at the same rotational speed as the first work roll and the second work rolls are heated to a temperature 10°C higher than the boiling point of the alcohol that makes up the suspension.The leading edge of the synthetic resin film that has been processed in the third step is inserted into the gap between the second work rolls, and the synthetic resin film is compressed.As a result, a sheet covered with the aggregate of flat powder whose one side is friction-welded to the synthetic resin film is continuously fed out of the gap between the second work rolls at a speed corresponding to the peripheral speed of the second work roll. The fifth step involves preparing a new container in which four freely rotating cylindrical rollers are placed parallel to each other, spaced apart, and the length of the width of the container, and filling the new container with a solvent that will dissolve the synthetic resin film in an amount that will keep the second and third rollers of the four cylindrical rollers constantly immersed in the solvent. In the sixth step, the leading edge of the sheet processed in the fourth step is brought into contact with the first roller, then moves along the side of the first roller near one-quarter of the way, then changes direction downward and moves to be immersed in the solvent, then contacts the side of the second roller. As the leading edge of the sheet moves, it moves along the side of the second roller near one-quarter of the way, then changes direction parallel to the bottom of a new container, moves through the solvent, and contacts the side of the third roller. After this, the leading edge of the sheet moves along the side of the third roller near one-quarter of the way, then changes direction upward and moves, and after being pulled up from the solvent, it contacts the side of the fourth roller. After this, the leading edge of the sheet moves along the side of the fourth roller near one-quarter of the way, then changes direction and moves to contact the top of the first roller of a container newly added in the seventh step, which has the same configuration as the new container. As the sheet moves continuously through the solvent, the dissolution phenomenon in which the synthetic resin film constituting the sheet dissolves in the solvent continues, and the synthetic resin film dissolves in the solvent. In the seventh step, the second and third rollers of the four cylindrical rollers that make up the newly added container are filled with solvent to a level that allows them to be constantly immersed in the solvent. After this, the same process as in the sixth step is repeated on the sheet that has been processed in the sixth step, and the sheet is continuously moved through the solvent, dissolving any synthetic resin film solution that may be slightly adhering to the sheet into the filled solvent. The sheet is then moved toward the entrance of the heat treatment device used in the eighth step at a speed equivalent to the peripheral speed of the second work roll. The solvent filled in the added container is replaced with fresh solvent at predetermined intervals. The eighth step involves preparing a heat treatment device that is exposed to a nitrogen atmosphere and heated to a temperature higher than the boiling point of the solvent, and the sheet that has been treated in the seventh step enters the heat treatment device at a speed equivalent to the peripheral speed of the second work roll, the solvent adhering to the sheet evaporates, and the sheet becomes a collection of flat powder with flat surfaces joined by friction welding, and the sheet is continuously fed out of the heat treatment device at a speed equivalent to the peripheral speed of the second work roll, and the fed sheet is continuously wound up by a winder that rotates at the same rotational speed as the second work roll. A method of continuously carrying out all eight of these processes is a method of continuously producing a sheet made from a collection of flat powder in which the flat surfaces of the flat powder are joined together by friction welding. The inventors have also filed a patent application (Japanese Patent Application No. 2019-143413) for a method for continuously producing soft magnetic sheets consisting of an assembly of soft magnetic flat powder in which the flat surfaces of the powder are directly bonded together by frictional heat. The prior application involves dissolving paraffin, primarily composed of an alkane having 20 or more carbon atoms, in an organic compound, pouring the assembly of soft magnetic flat powder into the paraffin solution, repeatedly applying vibration acceleration in three directions, and overlapping the flat surfaces of the soft magnetic flat powder through the paraffin solution. The organic compound is then vaporized, and the thermally dissolved paraffin is solidified. The assembly of soft magnetic flat powder, with its flat surfaces overlapping each other through the solidified paraffin, is then compressed in a cold rolling mill to continuously produce a sheet consisting of the assembly of soft magnetic flat powder in which the flat surfaces of the soft magnetic flat powder are joined together by frictional heat. In contrast, the present invention involves placing a collection of flat powder in alcohol with a viscosity of 6-10 mPa·s at 20°C and a boiling point below 200°C, repeatedly applying vibration acceleration in three directions to create a suspension consisting of a collection of flat powder in which the flat surfaces of the flat powder overlap with each other via the alcohol. Furthermore, a synthetic resin film is inserted into the gap between two work rolls, with the lower work roll partially immersed in the suspension, and the suspension is applied to one side of the synthetic resin film. This synthetic resin film is then compressed using a cold rolling mill to form a sheet in which the collection of flat powder, with its flat surfaces joined by friction welding, is friction-welded to one side of the synthetic resin film. The sheet is then moved through a solvent that dissolves the synthetic resin film, dissolving it in the solvent. The sheet is then washed with the solvent, and the solvent is then evaporated, resulting in a continuous production of sheets consisting only of the collection of flat powder in which its flat surfaces are friction-welded. Therefore, with regard to a method for continuously producing sheets consisting of a collection of flat powder whose flat surfaces are joined together by friction welding, the present invention differs from the prior application in that a suspension is applied to one side of a synthetic resin film, and then the collection of flat powder whose flat surfaces are joined together by friction welding is joined to one side of the synthetic resin film, and then the synthetic resin film is dissolved in a solvent to create a sheet consisting of the collection of flat powder, and compared to the prior application, sheets can be produced continuously more easily. [Background technology]

[0002] Flat powders are used for a variety of purposes depending on the material. Metal flake powders are the most common type. Aluminum and brass flake powders are used as raw materials for decorative pigments that create the brilliance required for metallic paints. Copper and silver flake powders are used as raw materials for conductive pastes, forming wiring for electrical circuits, internal electrodes for ceramic capacitors, electrodes for solar cells, and the formation of electromagnetic shielding and antistatic films. Pure iron flake powder has high magnetic flux density and increased magnetic permeability due to the shape anisotropy caused by the flattening process, making it suitable for use in dust cores and electromagnetic shielding sheets. Glass flake powder is composited with thermoplastic resins to serve as a filler that enhances their heat resistance, corrosion resistance, and mechanical strength. Glass flake powder coated with metals or metal oxides is used in inorganic pigments that create various types of lustre and is also used as a raw material for cosmetics. Other examples include flat powders made of metal oxides such as mica, alumina, silica, and iron oxide, and flat powders of graphite called scaly graphite or flake graphite powder.

[0003] When forming a sheet from a collection of flat powder, if the flat surfaces overlap, the amount of flat powder used can be reduced and the properties of the flat powder surfaces can be utilized in the sheet. Furthermore, if a sheet can be formed using only flat powder, the sheet will have the properties of the flat powder. However, there are no such cases. For example, Patent Document 1 describes a conductive paste in which copper flake powder is coated with tertiary amine-substituted polystyrene. However, because the copper flake powder is bonded to itself via tertiary amine-substituted polystyrene, and the conductivity of tertiary amine-substituted polystyrene is significantly lower than that of copper, the conductivity of a conductive sheet formed using the conductive paste is inferior to that of copper. Furthermore, because the copper flake powder does not overlap to form a sheet, the proportion of tertiary amine-substituted polystyrene in the sheet is not constant, and the sheet's conductivity is further reduced by partially occupying a larger proportion. Furthermore, if the proportion of copper flake powder in the conductive paste is increased to improve conductivity, the proportion of organic binder must be increased to ensure the copper flake powder's dispersibility, which increases the viscosity of the conductive paste and makes printing or applying the conductive paste difficult. Patent Document 2 also describes a composite magnetic sheet that suppresses high-frequency electromagnetic noise, using magnetic flat powder dispersed in an organic binder. However, because the organic binder is non-magnetic, the presence of the organic binder reduces the efficiency of absorbing electromagnetic noise. Furthermore, because the flat surfaces of the magnetic flat powder do not overlap to form a composite magnetic sheet, the flat surfaces do not absorb electromagnetic noise, reducing the efficiency of electromagnetic noise absorption by the flat magnetic powder. Furthermore, as in Patent Document 1, increasing the proportion of magnetic flat powder in the binder to improve the efficiency of absorbing electromagnetic noise increases the viscosity of the paste, making it difficult to print or apply the paste. Furthermore, Patent Document 3 describes a conductive resin composition that forms a conductive pattern in which flake powder is dispersed in an organic binder. However, because the organic binder is insulating, the presence of the organic binder reduces the conductivity of the conductive pattern. Furthermore, because the flat surfaces of the flake powder do not overlap to form a conductive pattern, similar to Patent Document 1, the proportion of the organic binder in the conductive pattern is not constant, and the conductivity of the conductive pattern is reduced. Furthermore, similar to Patent Document 1, increasing the proportion of flake powder in the paste to improve conductivity increases the viscosity of the paste, making it difficult to print or apply the paste. In all three of the conventional technologies described above, the flat surfaces of the flat powder do not overlap. In addition, because the flat powder is bonded via an organic substance, the properties of the organic substance are reflected in the assembly of the flat powder. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2012-52181 [Patent Document 2] Japanese Patent Application Publication No. 2018-73932 [Patent Document 3] Japanese Patent Application Laid-Open No. 2012-216286 Summary of the Invention [Problem to be solved by the invention]

[0005] However, because flat powders have unique shapes and particle size distributions, it is difficult to directly bond flat powder particles together. For this reason, in conventional technology, a polymeric material is added to a group of flat powder particles as a binder to bond the flat powder particles together, and the flat powder particles are bonded together via the polymeric material. However, because the polymeric material has different properties from the flat powder, the group of flat powder particles bonded together via the polymeric material loses its properties from the flat powder. Thus, when flat powder particles are bonded together via the bonding of dissimilar materials, the properties of the dissimilar materials are reflected, and the inherent properties of the flat powder are sacrificed. Furthermore, even if a polymeric material is added as a binder to a group of flat powder particles, it is even more difficult to overlap the flat surfaces of the flat powder particles and directly bond the flat powder particles together. Incidentally, flat powders are made of a wide variety of materials, such as inorganic substances, metal oxides, metals, or alloys, and each has its own unique shape and particle size distribution. Therefore, regardless of the material, shape, or particle size distribution of the flat powder, if the flat surfaces of the flat powder could be directly bonded to each other, a sheet could be formed from a collection of flat powders that uses less flat powder, is thin, and has fewer size restrictions, and the sheet would have the properties of flat powders made from various materials. However, no such attempt has been made to date. Therefore, forming a sheet made of a collection of flat powder particles in which the flat surfaces of the flat powder particles are directly bonded to each other involves the following problems. First, a method for overlapping flat surfaces of flat powders regardless of the material, shape, or particle size distribution of the flat powders is found. Therefore, a method for overlapping flat surfaces of flat powders via a liquid is found. In other words, because liquids deform freely when stress is applied, it becomes possible to overlap flat surfaces of flat powders via a liquid. Therefore, the first object of the present invention is to find a method for creating a suspension in which a collection of flat powders is dispersed in a liquid. Furthermore, the second object of the present invention is to find a method for creating a suspension in which flat surfaces of flat powders overlap via a liquid. Second, a method for creating a sheet consisting of a collection of flat powder whose flat surfaces are overlapping and bonded together is found. Therefore, the third object of the present invention is to find a method for attaching a suspension in which the flat surfaces of flat powder are overlapping and bonded together via a liquid to a sheet with few size restrictions. Furthermore, the fourth object of the present invention is to find a method for forming a collection of flat powder whose flat surfaces are overlapping and bonded together on the surface of a sheet with few size restrictions. Furthermore, the fifth object of the present invention is to find a method for removing a sheet with few size restrictions from a collection of flat powder whose flat surfaces are overlapping and bonded together. As a result, a new sheet is created from a collection of flat powder whose flat surfaces are overlapping and bonded together. Third, to find a method for continuously producing a sheet made of a collection of flat powder in which the flat surfaces of the flat powder are directly bonded together, using an inexpensive method. Therefore, the sixth object of the present invention is to find a method for continuously producing a sheet made of a collection of flat powder in which the flat surfaces of the flat powder are directly bonded together, using inexpensive raw materials and an inexpensive processing method. These six problems are the problems that the present invention aims to solve. [Means for solving the problem]

[0006] A method for continuously producing a sheet made of an assembly of flat powder in which flat surfaces of the flat powder are joined together by friction welding, comprises the steps of: a first step of installing in the container first work rolls consisting of two cylinders, each having the first feature of being wider than the width of the synthetic resin film, a second feature of being provided at an end of the container with a drawing device for drawing out the roll of material around which the synthetic resin film is wound, and a third feature of being provided in the container with first work rolls consisting of two cylinders and having the following five features, vertically adjacent to each other in the center of the container so as to have the length of the container's width, and placing the container on a vibration table of a vibration exciter; the first work rolls consisting of two cylinders, each having the first feature of being provided in the container with the same width as the container, the second feature of being provided with the same diameter, the third feature of being provided with a gap between the two work rolls set to a thickness obtained by adding the thickness of the synthetic resin film to a thickness for adsorbing the suspension prepared in the second step onto one side of the synthetic resin film, the fourth feature of being provided with the first work rolls rotating in opposite directions at the same peripheral speed so as to complete one rotation in 15 seconds or more, and the fifth feature of being provided in a position where a portion of the lower work roll is constantly immersed in the suspension prepared in the second step; A second process is to charge the container with a larger amount of flat powder than is necessary for continuously manufacturing a sheet made of a flat powder collection in which the flat surfaces of the flat powder are bonded together, and to use an alcohol having a first characteristic of a viscosity of 6-10 mPa·sec at 20°C and a second characteristic of a boiling point lower than 200°C, the smaller the average particle size of the flat powder, the higher the viscosity of the alcohol used, and to fill the container with an amount of alcohol so that a portion of the lower work roll in the container is constantly immersed in the alcohol, and then to operate a vibrator in which the container is placed, and to repeatedly apply vibrations to the container in the up-down, left-right, and front-back directions, creating a suspension in the container in which the flat surfaces of the flat powder are overlapped via the alcohol, and then to remove the container from the vibration table. a third step of setting a roll of synthetic resin film wound around the roll of material having the width of the sheet made of the flat powder mass to be produced in a roll-pulp pulling device, and continuously pulling out the synthetic resin film from the roll of material at a speed corresponding to the peripheral speed at which the first work roll rotates; thereafter, inserting a leading end of the pulled-out synthetic resin film into the gap between the first work rolls, and, as the first work roll rotates, continuously feeding out the synthetic resin film with the suspension adhered to one side of the synthetic resin film from the gap between the first work rolls at a speed corresponding to the peripheral speed at which the first work roll rotates; The first feature is that the width of the work rolls made of two cylinders is the same and wider than the width of the synthetic resin film; the second feature is that the diameter of the work rolls made of two cylinders is the same and is 1 / 10 or less of the width of the synthetic resin film; the third feature is that the gap between the two work rolls is set by a thickness that is thinner than the thickness of the flat powder mass where the flat surfaces are joined together plus the thickness of the synthetic resin film; the fourth feature is that the two work rolls rotate in opposite directions at the same rotation speed as the first work roll; and the fourth feature is that the work rolls are set at a temperature 10°C above the boiling point of the alcohol that constitutes the suspension. A multi-stage rolling mill having a second work roll consisting of two cylinders and also having the fifth feature of heating the two work rolls to a temperature 100°C higher is prepared in advance, and the leading end of the synthetic resin film that has been processed in the third step is inserted into the gap between the second work rolls. As a result, the leading end of the synthetic resin film is drawn into the gap between the second work rolls, and the synthetic resin film is continuously subjected to a compressive stress according to the size of the gap between the second work rolls. At this time, alcohol is first removed from the suspension that has been evenly adhered to one side of the synthetic resin film. The flat powder vaporizes, and the flat surfaces of the flat powder deposit over the entire surface of one side of the synthetic resin film, overlapping with each other, and one side of the synthetic resin film is covered with the flat powder cluster. Next, compressive stress begins to be applied to the flat powder cluster and the synthetic resin film, and first the surface layer of the flat powder cluster collapses, and the surface layer of the flat powder cluster deposited at the end of the synthetic resin film moves to the end, and the flat powder clusters that make up the surface layer overlap with each other at the end, and the surface layer of the flat powder cluster deposited other than at the end falls after the gap of the second work roll. The flat powder moves toward the flat surface of the flat powder. Furthermore, the compressive stress is applied to the collection of flat powder, and the gaps between the overlapping flat surfaces of the flat powder gradually narrow. When the flat surfaces come into direct contact with each other, frictional heat is generated on the flat surfaces, and all of the overlapping flat surfaces are bonded together by the frictional heat, forming a collection of flat powder in which the flat surfaces of the flat powder are directly bonded together. Furthermore, the synthetic resin film undergoes elastic or plastic deformation, and the collection of flat powder in which the flat surfaces are bonded together is bonded by friction welding to the entire surface of one side of the elastically or plastically deformed synthetic resin film.a fourth step in which a sheet in which the collection of flat powders joined by friction welding covers the entire surface of one side of the synthetic resin film is continuously fed from the gap between the second work rolls at a speed corresponding to the peripheral speed of the second work rolls; A new container is prepared in advance, which has both a first feature that the width of the container is wider than the width of the synthetic resin film, and a second feature that four freely rotating cylindrical rollers having the same length and diameter are installed in the container parallel to each other and spaced apart, the length of the width of the container, and a solvent in which the synthetic resin film dissolves is filled into the new container in an amount that allows a second roller and a third roller of the four cylindrical rollers to be constantly immersed in the solvent. The four cylindrical rollers are arranged in the new container such that the first roller is positioned at a height corresponding to the height at which the top of the first roller contacts the sheet discharged from the nip of the second work roll in the fourth step, and at a position 1 cm or more away from one side of the new container. a fifth step of placing the four rollers in the new container in such positions, placing a second roller at a position that is farther from one side of the new container by the size of the first roller compared to the position of the first roller and at a position that is farther from the bottom of the new container by 1 cm or more; placing a fourth roller at a position that is farther from the other side of the new container by 1 cm or more and at a position where the top of the fourth roller is at the same height as the top of the first roller; and placing a third roller at a position that is farther from the other side of the new container by the size of the fourth roller compared to the position of the fourth roller and at a position that is farther from the bottom of the new container by 1 cm or more, the same as the bottom of the new container as the second roller; In the fourth step, the leading edge of the sheet fed out from the gap between the second work rolls comes into contact with the top of the first roller, and as the leading edge of the sheet moves, the leading edge of the sheet moves along the side of the first roller near 1 / 4 of the way, after which the leading edge of the sheet changes direction downward and moves and is immersed in the solvent, and further comes into contact with the side of the second roller, and as the leading edge of the sheet moves, the leading edge of the sheet moves along the side of the second roller near 1 / 4 of the way, after which the leading edge of the sheet changes direction to a direction parallel to the bottom of the new container and moves through the solvent, and comes into contact with the side of the third roller, and as the leading edge of the sheet moves, the leading edge of the sheet moves along the side of the third roller near 1 / 4 of the way, and the leading edge of the sheet then changes its moving direction upward and moves upward, and after being pulled up from the solvent, comes into contact with the side of the fourth roller; as the leading edge of the sheet moves, the leading edge of the sheet moves along the side of the fourth roller, which is approximately 1 / 4 of the way around; then the leading edge of the sheet changes its moving direction so as to come into contact with the top of the first roller of a container newly added in the seventh step and having the same configuration as the new container, and moves at a speed equivalent to the peripheral speed of the second work roll; by treating the sheet in this new container, the sheet continues to move through the solvent, and the dissolution phenomenon in which the synthetic resin film constituting the sheet dissolves in the solvent continues to progress, resulting in the synthetic resin film dissolving in the solvent; a sixth step in which the synthetic resin film dissolves in the solvent; a seventh step in which an additional container having the same configuration as the new container used in the fifth step is prepared in advance, and the additional container is filled with the solvent in an amount such that a second roller and a third roller of four freely rotating cylindrical rollers constituting the additional container are constantly immersed in the solvent; thereafter, the same treatment as that performed in the sixth step is repeatedly performed on the sheet that has been treated in the sixth step, and the sheet is continuously moved in the filled solvent, and any solution of the synthetic resin film that has slightly adhered to the sheet is dissolved in the filled solvent; thereafter, the sheet is moved toward the entrance of a heat treatment device used in the eighth step at a speed equivalent to the peripheral speed of the second work roll; and the solvent filled in the additional container is replaced with new solvent at a predetermined cycle; an eighth step in which a heat treatment device having a first feature of being exposed to a nitrogen atmosphere and a second feature of being heated to a temperature higher than the boiling point of the solvent is prepared in advance, the sheet having been treated in the seventh step enters the heat treatment device at a speed corresponding to the peripheral speed of the second work roll, the solvent adhering to the sheet evaporates, the sheet becomes a collection of flat powder whose flat surfaces are joined by friction welding, the sheet consisting of the collection of flat powder whose flat surfaces are joined is continuously fed out of the heat treatment device at a speed corresponding to the peripheral speed of the second work roll, and the fed sheet is continuously wound up by a winder rotating at the same rotational speed as the second work roll; The method of continuously carrying out all eight of these processes is a method of continuously producing a sheet made from a collection of flat powder in which the flat surfaces of the flat powder are joined together by friction welding.

[0007] In other words, according to this method, if all of the following eight steps are carried out consecutively, a sheet made of a collection of flat powder in which the flat surfaces of the flat powder are joined together by friction welding is continuously produced. Here, the details of the processing in the eight steps and the effects of the processing will be explained. In the first step, a suspension in which flat surfaces overlap each other via alcohol is continuously applied to one side of a synthetic resin film. A first work roll, consisting of two cylindrical work rolls arranged adjacent to each other in the vertical direction, is installed in the center of a container, and the container is placed on a vibration table. In other words, a synthetic resin film is an inexpensive film that is thin, solvent-soluble, and has few size and length restrictions. Therefore, the synthetic resin film was used as a medium for applying a suspension in which clusters of flat powder are dispersed in alcohol. The container in which the first work roll is installed has a first feature in which the container width is wider than the width of the synthetic resin film, a second feature in which a drawing device for drawing out the roll of material wound with synthetic resin film is installed at the end of the container, and a third feature in which first work rolls consisting of two cylinders and having the following five features are installed adjacent to each other in the vertical direction in the center of the container so as to have the length of the container width. In other words, in order to continuously draw out the synthetic resin film from the roll of material wound with synthetic resin film, the drawing device for drawing out the roll of material wound with synthetic resin film is installed at the end of the container. Furthermore, the first work rolls consisting of two cylinders have the following five features. The first feature is that the work rolls are installed within the container with the same width as the container; the second feature is that they have the same diameter; the third feature is that the gap between the two work rolls is set to a thickness equal to the thickness of the suspension adsorbed on one side of the synthetic resin film in the second process plus the thickness of the synthetic resin film itself; the fourth feature is that the work rolls rotate in opposite directions at the same peripheral speed, completing one rotation every 15 seconds or more; and the fifth feature is that the lower work roll is positioned so that a portion of it is constantly immersed in the suspension prepared in the second process. In other words, as the synthetic resin film enters the gap between the two work rolls, the suspension adhering to the lower work roll is transferred to one side of the synthetic resin film. The thickness of the suspension adsorbed on one side of the synthetic resin film is determined in advance by actual measurement. Furthermore, the rotation speed of the two work rolls is slow, with one rotation every 15 seconds or more, so that the suspension is reliably adhered to one side of the synthetic resin film without scattering. In the second step, a suspension in which the flat surfaces of the flat powder overlap each other through alcohol is created in a container. To achieve this, the container is filled with the amount of flat powder needed to continuously produce sheets made of the flat powder. Furthermore, alcohol with a viscosity of 6-10 mPa·s at 20°C and a boiling point below 200°C is used. The smaller the average particle size of the flat powder, the higher the viscosity of the alcohol. The number of layers of flat powder whose flat surfaces overlap each other through alcohol is increased to ensure the formation of a sheet made of flat powder whose flat surfaces are bonded together. The container is filled with an amount of alcohol so that a portion of the work roll below the first work roll is constantly immersed in alcohol. After this, the vibrator is operated, repeatedly applying vertical, horizontal, and front-to-back vibrations to the container, creating a suspension in which the flat surfaces of the flat powder overlap each other through alcohol. In other words, when vibration acceleration is applied to the container, the alcohol moves in the direction of the vibration acceleration. As the alcohol moves, the flat powder also moves. On the other hand, flat powders with a large aspect ratio (the ratio of the long diameter to the thickness) move through the liquid with the flat surface facing up, which places the least strain on the flat powder, so the flat powder moves through the alcohol with the flat surface facing up in the vibration direction. Therefore, when vibration acceleration in three directions is repeatedly applied to a collection of flat powder, the flat surfaces of the flat powder overlap each other through the alcohol, forming a suspension. In the third step, the suspension is continuously applied to one side of the synthetic resin film. To this end, a roll of synthetic resin film wound around it is set in a roll-up device, and the synthetic resin film is continuously drawn off from the roll at a speed equivalent to the peripheral speed of the first work roll. The leading edge of the drawn synthetic resin film is then inserted into the nip of the first work roll, and the first work roll is operated. During this process, a portion of the lower work roll is constantly immersed in the suspension. Therefore, when the synthetic resin film is sandwiched between the two work rolls, one side of the synthetic resin film comes into contact with the surface of the lower work roll. Since the suspension is adhered to the surface of the lower work roll, the suspension is transferred to one side of the synthetic resin film. The synthetic resin film with the suspension adhered to one side is then continuously fed out of the nip of the first work roll at the peripheral speed of the first work roll. Furthermore, since the synthetic resin film moves at a slow speed equivalent to the peripheral speed of the first work roll, the suspension adheres reliably to one side of the synthetic resin film, and the adhered suspension does not fall off from the other side of the synthetic resin film due to the adhesive force based on the viscosity of the alcohol. In the fourth step, a sheet is continuously produced in which a collection of flat powders joined by friction welding covers the entire surface of one side of a synthetic resin film. To this end, a multi-high rolling mill is prepared in advance, which has a second work roll consisting of two cylinders and which has the following five characteristics: The two cylindrical work rolls have a first characteristic of having the same width but wider than the width of the synthetic resin film, a second characteristic of having the same diameter but less than 1 / 10 the width of the synthetic resin film, a third characteristic of having a gap between the two work rolls set by a thickness less than the sum of the thickness of the collection of flat powders whose flat surfaces are joined together and the thickness of the synthetic resin film, a fourth characteristic of rotating in opposite directions to the first work roll at the same rotational speed as the first work roll, and a fifth characteristic of being heated to a temperature 10°C higher than the boiling point of the alcohol that constitutes the suspension. Although the width of the two work rolls is wider than the width of the sheet to be produced, their diameters are less than 1 / 10 of the sheet width, causing elastic deformation when the two work rolls rotate in opposite directions. A multi-high rolling mill was used to suppress this elastic deformation by rotating the other backup roll. This ensures that the compressive stress applied to the synthetic resin film from the gap between the two work rolls is continuously applied as a constant compressive stress. An example of a multi-high rolling mill is a 12-high rolling mill. Furthermore, because the diameters of the two work rolls are less than 1 / 10 of the width of the synthetic resin film and they rotate in opposite directions once every 15 seconds or more, sufficient contact time between the two work rolls and the synthetic resin film is ensured. Furthermore, when the alcohol evaporates from the suspension, the accumulation of flat powder deposited on one side of the synthetic resin film does not fall off the synthetic resin film. If the flat powder has a high hardness, it is necessary to increase the compressive stress applied to the collection of flat powder particles, bringing the flat surfaces of the flat powder into contact with each other and joining them together. For this reason, when using flat powder with a high hardness, the gap between the two work rolls is narrowed to join the flat surfaces of the flat powder together, and the collection of flat powder particles with their flat surfaces joined together is joined to the plastically deformed synthetic resin film by friction welding. The thickness of the collection of flat powder particles with their flat surfaces joined together is determined in advance by actual measurement. After this, the leading edge of the synthetic resin film that has been processed in the third step is inserted into the gap between the two work rolls. The leading edge of the synthetic resin film is pulled into the gap between the two work rolls, and the synthetic resin film is continuously subjected to compressive stress corresponding to the size of the gap between the two work rolls. Furthermore, because the diameter of the two work rolls is less than 1 / 10 of the width of the synthetic resin film and the rotation speed is longer than 15 seconds per rotation, the contact time between the synthetic resin film and the two work rolls is ensured. At this time, the alcohol first evaporates from the suspension that is evenly adhered to one side of the synthetic resin film, and the flat surfaces of the flat powder overlap and precipitate over the entire surface of the synthetic resin film, covering one side of the synthetic resin film with a collection of flat powder. Next, compressive stress begins to be applied to the flat powder cluster and the synthetic resin film. Initially, the surface layer of the flat powder cluster collapses. The flat powder cluster deposited on the edge of the synthetic resin film moves toward the edge, causing the flat surfaces to overlap. The surface layer of the flat powder cluster deposited outside the edge moves toward the rear of the gap between the two work rolls. Furthermore, compressive stress is applied to the flat powder cluster, gradually narrowing the gap between the overlapping flat surfaces. When the flat surfaces come into direct contact with each other, frictional heat is generated on the flat surfaces. The frictional heat bonds all the overlapping flat surfaces together, forming a cluster of flat powder in which the flat surfaces of the flat powder are directly bonded together. Furthermore, the synthetic resin film undergoes elastic or plastic deformation, and the cluster of flat powder in which the flat surfaces are bonded together is friction-welded to the entire surface of one side of the elastically or plastically deformed synthetic resin film. As a result, a sheet in which a collection of flat powder joined by friction welding covers the entire surface of one side of a synthetic resin film is continuously fed out from the gap of the second work roll at a speed equivalent to the peripheral speed of the second work roll. In the fifth step, a new container to be used when dissolving the synthetic resin film is prepared in advance. That is, a new container is prepared in advance that has both a first feature that the width of the container is wider than the width of the synthetic resin film and a second feature that four freely rotating cylindrical rollers of the same length and diameter are installed inside the container, parallel to each other and spaced apart, the length of the width of the container. Next, the new container is filled with a solvent that will dissolve the synthetic resin film in an amount that will constantly immerse the second and third rollers of the four cylindrical rollers in the solvent. The four freely rotating cylindrical rollers are positioned as follows: The first roller is installed at a position where its top is at a height corresponding to the height at which it contacts the sheet discharged from the nip of the second work roll in the fourth process, and is located at a distance of at least 1 cm from one side of the new container. The second roller is installed at a position farther from one side of the new container than the first roller by the size of the first roller and at a distance of at least 1 cm from the bottom of the new container. The fourth roller is installed at a position farther from the other side of the new container by the size of the fourth roller, and at a position where its top is at the same height as the top of the first roller. The third roller is installed at a position farther from the other side of the new container than the fourth roller by the size of the fourth roller, and at the same position as the second roller, and at a distance of at least 1 cm from the bottom of the new container. In the sixth step, the sheet fed out of the gap between the second work rolls in the fourth step is immersed in a solvent filled in a new container to dissolve the synthetic resin film. To this end, the leading edge of the sheet fed out of the gap between the second work rolls is brought into contact with the top of the first roller, and as the leading edge of the sheet moves, it moves along the side of the first roller, approximately one-quarter of the way up. The leading edge then changes direction downward, immerses in the solvent filled in a new container, and then contacts the side of the second roller. The leading edge then moves along the side of the second roller, approximately one-quarter of the way up. The leading edge then moves in a direction parallel to the bottom of the new container, advances through the solvent, and contacts the side of the third roller. The leading edge then moves further, moving along the side of the third roller, approximately one-quarter of the way up. The leading edge then changes direction upward, rises from the solvent, and contacts the side of the fourth roller. As the leading edge of the sheet moves, it moves along the side of the fourth roller, approximately one-quarter of the way around. The leading edge then changes direction so that it contacts the top of the first roller in a container newly added in the seventh process, which has the same configuration as the new container. The sheet then moves at a speed equivalent to the peripheral speed of the second work roll. As the sheet moves through the solvent-filled container, it moves continuously through the solvent, and the dissolution phenomenon in which the synthetic resin film constituting the sheet dissolves in the solvent continues, dissolving the synthetic resin film into the solvent. Once the process of dissolving the synthetic resin film in the solvent is complete, the new container is heated to the boiling point of the solvent, vaporizing the solvent, and the synthetic resin film remaining in the new container is reused. The vaporized solvent is then recovered and reused. In the seventh step, an additional container having the same configuration as the new container used in the fifth step is prepared in advance. Specifically, the additional container is filled with solvent, and the sheet is continuously moved through the solvent to dissolve any synthetic resin film that may be slightly adhering to the sheet in the filled solvent. To this end, the additional container is filled with solvent in an amount that will ensure that the second and third rollers of the four cylindrical rollers are constantly immersed in the solvent. After this, the sheet that has been processed in the sixth step is subjected to the same treatment as in the sixth step. Then, the sheet is moved toward the entrance of the heat treatment device used in the eighth step at a speed equivalent to the peripheral speed of the second work roll. In the eighth step, the sheet processed in the seventh step enters a heat treatment device, where the solvent adhering to the sheet evaporates, turning the sheet into a collection of flat powder whose flat surfaces are friction-welded together. To this end, a heat treatment device having a first characteristic of being exposed to a nitrogen atmosphere and a second characteristic of being heated to a temperature higher than the boiling point of the solvent is prepared in advance. Furthermore, the sheet processed in the seventh step enters the heat treatment device at a speed corresponding to the peripheral speed of the second work roll, where the solvent adhering to the sheet evaporates, turning the sheet into a collection of flat powder whose flat surfaces are friction-welded together. After this, the sheet consisting of the collection of flat powder whose flat surfaces are friction-welded together is continuously fed out of the heat treatment device at a speed corresponding to the peripheral speed of the second work roll, and the fed sheet is continuously wound up by a winder rotating at the same rotational speed as the second work roll. After the sheet processing is completed, a new container is heated to the boiling point of the solvent, where the solvent evaporates, and the synthetic resin film remaining in the new container is reused. Moreover, the vaporized solvent is recovered and reused. By continuously carrying out all of these eight steps, a sheet made of a collection of flat powder in which the flat surfaces of the flat powder are joined together by friction welding is continuously produced. The process consisting of these eight steps produces the following results, solving the six problems described in paragraph 5: In the second step, a suspension in which the flat surfaces of the flat powder overlap each other via alcohol is created in a container. This solves the first and second problems described in paragraph 5. In the third step, the suspension was continuously applied to one side of the synthetic resin film, thereby solving the third problem described in paragraph 5. In the fourth step, a sheet was continuously produced in which a collection of flat powders joined by friction welding covered the entire surface of one side of a synthetic resin film. This solves the fourth problem described in paragraph 5. In the sixth step, the synthetic resin film that constitutes the sheet is dissolved in a solvent. Furthermore, in the seventh step, the solution of the synthetic resin film that was slightly adhering to the sheet is dissolved in newly added solvent. Furthermore, in the eighth step, the solvent that was adhering to the sheet is evaporated, and the sheet is turned into a collection of flat powder with flat surfaces joined by friction welding. As a result, the fifth problem described in paragraph 5 is solved. In the eight-step process described above, the raw materials used were a collection of flat powder, alcohol, and a synthetic resin film. All of these are general-purpose industrial materials. Furthermore, all eight steps of the process are extremely simple. As a result, the sixth problem described in paragraph 5 is solved. As a result, all six problems described in paragraph 5 are resolved.

[0008] The method for continuously producing a sheet made of an aggregate of flat powders in which the flat surfaces of the flat powders are joined by friction welding as described in paragraph 6 includes the steps of: The flat powder described in paragraph 6 is a flake powder of any one of soft metals consisting of gold powder, silver powder, copper powder, tin powder, zinc powder, and aluminum powder, which is obtained by pulverizing soft metal powder with a stamp mill; Or, The flat powder described in paragraph 6 is a flat powder made of one of the following soft magnetic alloys: silicon steel powder with an added amount of silicon of less than 10% obtained by attriting atomized soft magnetic powder or reduced soft magnetic powder using a media stirring mill; permalloy powder with an added amount of nickel of 50% or less; sendust powder with an added amount of aluminum of 1 / 2 or more of the added amount of silicon; or electromagnetic stainless steel powder with an added amount of aluminum of less than 2%; Or, The flat powder described in paragraph 6 is a flat powder made of any one of metal oxides, which is selected from the group consisting of alumina powder produced by hydrothermal synthesis of aluminum hydroxide, mica powder produced by finely grinding muscovite, glass flake powder produced by crushing molten glass expanded into a hollow shape, and hematite powder precipitated by hydrothermal treatment of yellow iron oxide in an alkaline aqueous solution, A method for continuously producing a sheet consisting of a collection of flat powder in which the flat surfaces of the flat powder are joined by friction welding, is to use any one of these 14 types of powder as the flat powder described in paragraph 6 and continuously carry out all of the eight processes described in paragraph 6.

[0009] In other words, flat powders having a plate-like, flaky, or scaly shape with a large aspect ratio are produced by a method specific to the powder. Here, we will explain the method for producing flat powders having a plate-like, flaky, or scaly shape with a large aspect ratio, the material of the produced powder, the specific properties of the powder, and the uses of sheets made of a collection of flat powders. The first type of flat powder is soft metal flake powder, which is produced by crushing soft metal powder using a stamp mill. Using a stamp mill, which is equivalent to a stamping machine, a mass of powder made of soft metals such as gold, silver, copper, tin, zinc, or aluminum is pounded with numerous metal pestles to flatten the soft metal powder into thin flakes. This process results in soft metal flake powder with a high aspect ratio (the ratio of the major axis to the powder thickness) and a smooth, nearly flat surface. Therefore, even with expensive gold or silver flake powder, a small amount of flake powder can be used to form a sheet with a metallic color, with flat surfaces bonded together. The raw metal powder is often high-purity, lead-free electrolytic metal powder. On the other hand, when producing aluminum flake powder, stearic acid is added as a grinding aid to crush the granular powder or foil cut pieces produced by atomization, because the aluminum powder is prone to combustion and adhesion when crushed in a stamp mill. The heat resistance temperature of flake powder of soft metals other than tin is determined by their softening point, and even electrolytic copper, which has a low softening point, can reach a high temperature of 800°C. Furthermore, soft metals other than tin do not exhibit low-temperature brittleness, allowing them to be used at extremely low temperatures. The melting point of 99.5% pure aluminum powder is 650°C. Therefore, sheets with overlapping flat surfaces bonded together can be used in harsh environments, such as high temperatures, extremely low temperatures, vacuums, and high pressures. On the other hand, tin has a melting point of 232°C and exhibits low-temperature brittleness at around -40°C, limiting the operating temperature of sheets made of tin flake powder alone. In addition, the surface of soft metal flake powder is flat and smooth, with a nearly uniform thickness of submicrons. Furthermore, soft metal flake powder has low hardness. Therefore, when a relatively small compressive stress is applied to a collection of flake powder in which flat surfaces overlap each other without any gaps, the flat surfaces come into contact and bond together. Because the area of ​​the bonded portions made of flat surfaces is large, the bonding strength between the flake powders is strong. Furthermore, the surface of a sheet made of bonded flat surfaces has a smooth surface that is nearly flat, resulting in a sheet with excellent lubricity. Copper and silver have high electrical and thermal conductivity among metals. Therefore, sheets, cut sheets, or folded sheets formed from a collection of copper or silver flake powder joined by friction welding are used as lightweight conductive or thermally conductive sheets, lightweight heat sinks, and as electrical circuit boards or electrodes. Tin has high electrical and thermal conductivity, low density, and solderability, so cut sheets are used as lightweight electrical circuit boards. Because tin has a low melting point of 232°C, it is not used for electrical circuit boards that are subject to high temperatures. Aluminum, like copper, has high electrical and thermal conductivity. Therefore, sheets, cut sheets, or sheets formed from a collection of aluminum powder joined by friction welding are used as lightweight conductive or thermally conductive sheets, lightweight heat sinks, and as lightweight electrical circuit boards or electrodes. The second type of flat powder is a flat powder made of a soft magnetic alloy. It is known that flattening soft magnetic powder in the plane direction, which is the easy axis of magnetization, reduces the demagnetizing factor, and the greater the flatness, the greater the imaginary part μ" of the complex permeability. On the other hand, it is also known that the absorption of electromagnetic waves in soft magnetic materials depends on the magnitude of the imaginary part μ" of the complex permeability and the magnitude of the electrical conductivity. Therefore, the use of conductive soft magnetic flat powder improves the ability to absorb electromagnetic noise. Furthermore, the flattening process for soft magnetic powder does not rely on long-term batch processing using a ball mill. Instead, atomized soft magnetic powder or reduced soft magnetic powder is subjected to attrition processing using a media agitation mill to produce soft magnetic flat powder. This allows for continuous production of flat powder in a short period of time, and soft magnetic flat powder can be produced through inexpensive processing. Furthermore, because the sheet is formed from a collection of flat powder with flat surfaces directly overlapping each other, a large-area soft magnetic sheet can be formed using a small amount of flat powder. Furthermore, the flat surfaces of the flat powder can participate in absorbing electromagnetic waves, resulting in a soft magnetic sheet with high electromagnetic wave reception sensitivity and excellent electromagnetic wave absorption performance. Therefore, the soft magnetic sheet maximizes the flatness effect of the flat powder. Furthermore, since the magnitude of the imaginary part of the complex permeability of the flat powder depends on the frequency band of the electromagnetic waves, the material of the soft magnetic flat powder is selected depending on the frequency of the electromagnetic noise to be absorbed. These flattened powders made from soft magnetic alloys include silicon steel powder with less than 10% silicon content, permalloy powder with less than 50% nickel content, sendust powder with more than half the amount of aluminum, and electromagnetic stainless steel powder with less than 2% aluminum content. In other words, silicon steel becomes brittle with increasing silicon content, making it impossible to flatten, so the silicon content must be kept below 10%. Furthermore, slight variations in the amount of silicon content significantly affect the permeability characteristics of silicon steel. Therefore, the amount of silicon content is determined based on the required permeability characteristics. Furthermore, while the manufacturing cost of permalloy increases with increasing nickel content, the permeability decreases with decreasing nickel content, so the nickel content is kept below 50%. Therefore, the amount of nickel content in permalloy is determined based on the required permeability characteristics. Sendust is hard and brittle, but adding a small amount of aluminum and reducing the amount of silicon makes it possible to flatten. On the other hand, Permendur is an alloy with cobalt, which makes it expensive to manufacture and unsuitable for flattening powder that absorbs electromagnetic noise. Furthermore, adding aluminum to electromagnetic stainless steel makes it easier to flatten. The complex permeability of the soft magnetic flat powders made from these four types of alloys changes significantly with slight changes in the composition of the components other than iron. Furthermore, the hardness of the atomized or reduced powders made from the four types of alloys varies depending on the alloy composition, so the flatness of the flat powder varies depending on the alloy composition, and the magnitude of the imaginary part of the complex permeability also varies. Furthermore, the frequency characteristics of the complex permeability vary significantly depending on the alloy composition. Therefore, soft magnetic sheets used for absorbing electromagnetic waves or preventing electromagnetic noise interference use different soft magnetic flat powder materials depending on the frequency band of the electromagnetic waves to be absorbed. The soft magnetic flat powder made from the four alloys has a higher hardness than the soft metal flake powder. Therefore, the compressive stress applied to the soft magnetic flat powder is large. Therefore, the gap between the two work rolls is narrowed depending on the hardness of the flat powder. This causes the synthetic resin film to plastically deform, and the flat powder particles, with their flat surfaces joined together, are friction-welded to the plastically deformed synthetic resin film. Even if a large compressive stress is applied to the hard soft magnetic flat powder, the flat powder particles are not bonded together by the entire overlapping flat surfaces. Therefore, the bonding strength between the flat powder particles is smaller than the bonding strength between soft metal flake powder particles. Furthermore, the size of the soft magnetic flaky powder made from the four types of alloys is nearly an order of magnitude smaller than the size of the soft metal flake powder mentioned above, and the aspect ratio of the soft magnetic flaky powder made from the four types of alloys is close to the aspect ratio of the soft metal flake powder. Meanwhile, the thickness of the overlapping soft magnetic flaky powder is nearly an order of magnitude thinner than the thickness of the synthetic resin film. Therefore, by narrowing the gap between the two work rolls by nearly an order of magnitude compared to the thickness of the soft magnetic flaky powder covering the entire synthetic resin film, the necessary compressive stress is applied to the soft magnetic flaky powder, and the flaky powder, with its flat surfaces joined together, is friction-welded to the plastically deformed synthetic resin film. The third type of flat powder is a metal oxide flat powder made of alumina, mica, glass, or hematite, which has a plate-like, flake-like, or scale-like shape. The first alumina, Al2O3, is produced by a method called hydrothermal synthesis, in which aluminum hydroxide is reacted with water under high temperature and pressure conditions. 14-15It has a high resistivity of Ω·cm, a high breakdown voltage of 10-15 kV / mm, and a dielectric constant of 9.5-9.7 at 1 MHz, making it an excellent insulator. It also has a high Mohs hardness of 9 and is heat-resistant to temperatures exceeding 1500°C, without being altered by frictional heat. Furthermore, alumina's thermal conductivity is 23-36 W / mK, which is one-tenth of the thermal conductivity of copper (386 W / mK), providing thermal insulation. For example, if a sheet made of alumina flake powder joined by friction welding measures 100 cm x 100 cm and is 12 μm thick, the resistance of the sheet made of alumina flake powder will be 0.8 x 10 17 Ω. Therefore, sheets using alumina flake powder have extremely high insulation resistance. They can also be used as high-temperature fireproof insulation materials and as lining and sealing materials for industrial furnaces such as heating and baking furnaces. The surface of the sheet has irregularities similar in size to the alumina flake powder, as well as the irregularities of the alumina flake powder that appear on the surface of the sheet. Therefore, when a cut sheet is placed on the surface of a substrate or part made of various materials and shapes and the surface of the cut sheet is uniformly compressed, the convex parts of the irregularities on the surface of the sheet come into contact with the surface of the substrate or part, and the cut sheet is joined to the surface of the substrate or part by friction welding at the contact points. This allows the formation of an insulating layer with extremely high insulation resistance and high heat resistance on the surface of substrates or parts made of various materials. Secondary mica K2Al4(Al2Si6O 20 Mica powder is a flaky powder made of potassium aluminum silicate (OH)4 (also known as mica), which is obtained by pulverizing and purifying muscovite. Mica powder has a high thermal decomposition temperature of 600-800°C, an extremely low thermal conductivity of 0.67 W / mK, a constant tensile strength of 250-300 MPa, and a deposition resistivity of 10 14 -10 16Its high dielectric constant (Ω·cm) and breakdown voltage (18-25kV / 0.1mm) make it an insulating sheet with extremely high insulation resistance. Similar to alumina, this insulating sheet can be used as a high-temperature refractory insulating material and as a lining or sealing material for industrial furnaces such as heating and baking furnaces. Furthermore, because mica flakes have a low Mohs hardness of 2.8-3.2, sheets made from mica flakes can be easily cut into any shape. Furthermore, the surface of the sheet has irregularities that are similar in size to the mica flakes, as well as irregularities that appear on the surface of the mica flakes. Therefore, when a cut sheet is placed on the surface of a substrate or part made of various materials and shapes and compressed evenly, the convex parts of the irregularities on the surface of the sheet come into contact with the surface of the substrate or part, and the cut sheet is joined to the surface of the substrate or part by friction welding at the contact points. As a result, an insulating layer with extremely high insulation resistance and excellent heat insulating effect is formed on the surface of substrates or parts made of various materials. The size of the alumina flake powder is nearly an order of magnitude smaller than the size of the soft metal flake powder mentioned above, and the aspect ratio of the alumina flake powder is close to that of the soft metal flake powder. Therefore, the thickness of the alumina flake powder is nearly an order of magnitude thinner than the thickness of the soft metal flake powder. Furthermore, alumina powder is a hard powder with a Mohs hardness of nearly 9, and does not undergo plastic deformation. On the other hand, the thickness of the overlapping alumina powder is an order of magnitude thinner than the thickness of the synthetic resin film. Therefore, by narrowing the gap between the two work rolls by nearly an order of magnitude smaller than the thickness of the synthetic resin film, the necessary compressive stress is applied to the alumina powder cluster, bonding the flat surfaces together and bonding the alumina flake powder cluster to the plastically deformed synthetic resin film. In contrast, the size of mica flake powder varies by an order of magnitude. Furthermore, the aspect ratio of the mica flake powder is close to that of the soft metal flake powder. Furthermore, the Mohs hardness of the mica flake powder is around 3, and it undergoes plastic deformation. Therefore, if the size of the mica flake powder is nearly an order of magnitude smaller than the size of the soft metal flake powder, the thickness of the overlapping mica powder is an order of magnitude thinner than the thickness of the synthetic resin film. Therefore, by narrowing the gap between the two work rolls by nearly an order of magnitude smaller than the thickness of the synthetic resin film, the necessary compressive stress is applied to the mica powder cluster, bonding the flat surfaces together and bonding the cluster of mica flake powder to the plastically deformed synthetic resin film. On the other hand, if the size of the mica flake powder is close to that of flake powder made of soft metal, the gap between the two work rolls can be made close to the thickness of the synthetic resin film, so that the necessary compressive stress is applied to the mica powder mass, bonding the flat surfaces together and bonding the mica flake powder mass to the elastically deformed synthetic resin film. The third type of glass flake powder is produced by expanding molten glass into a hollow shape, thinning the film thickness, and then crushing it to produce scaly glass flake powder. The glasses used to produce glass flake powder are C-glass and E-glass. C-glass contains 8 wt% of Na2O and K2O in its chemical composition, so it is mainly used in applications that make use of its acid-resistant properties. In contrast, E-glass contains only 0.3 wt% of Na2O and K2O, and is used as a general-purpose glass. The density of E-glass is 2.6 g / cm 3 The softening point is 840°C, the tensile strength is 3.4 GPa, the thermal conductivity is 1.03 W / mK, and the volume resistivity is 10 15 Glass flakes are an excellent insulator, with a high dielectric constant (Ω·cm), a dielectric constant (dielectric constant) of 6.13 at 1 MHz, and a dielectric dissipation factor (DTF) of 0.0035 at 1 GHz. Therefore, sheets made from glass flake powder can be lightweight and combine thermal insulation, insulation, and high tensile strength. Furthermore, glass flakes have a Mohs hardness of 5-6, allowing them to be cut by bending without producing chips. Therefore, sheets made from glass flake powder can be cut into any shape. Furthermore, the surface of the sheet has irregularities similar to the size of the glass flakes. Therefore, when a cut sheet is placed on the surface of a substrate or part made of various materials and shapes and compressed evenly, the convex parts of the irregularities on the surface of the sheet come into contact with the surface of the substrate or part, and the cut sheet is bonded to the surface of the substrate or part by friction welding at the contact points. This allows a lightweight glass sheet layer to be formed on the surface of a variety of substrates or parts, combining thermal insulation, insulation, and tensile strength. The glass flake powder has a particle size similar to that of the soft metal flake powder described above, but is one order of magnitude thicker than the soft metal flake powder, has an aspect ratio similar to that of the soft metal flake powder, and has a Mohs hardness of approximately 5, which is approximately twice that of the soft metal flake powder, making it less susceptible to plastic deformation. On the other hand, the thickness of the overlapping glass flake powder is similar to that of a synthetic resin film. Therefore, by making the gap between the two work rolls similar to the thickness of the synthetic resin film, the necessary compressive stress is applied to the mica powder cluster, bonding the flat surfaces together and bonding the glass flake powder cluster to the plastically deformed synthetic resin film. The fourth hematite (α-Fe2O3) powder is produced by hydrothermally treating yellow iron oxide (hydrated iron oxide α-FeOOH) in an alkaline solution to precipitate flaky hematite. The resistivity of hematite as an insulator is 10 8 Although hematite has a low resistance (Ω·cm), its melting point is high (1565°C), making it a non-flammable powder. Hematite powder is also used as a red pigment (red iron oxide) in lacquerware. Therefore, sheets made from hematite powder aggregates have a bright red color and excellent heat resistance. Hematite also has a high Mohs hardness (6.3), but because sheets made from hematite powder aggregates are thin, they can be cut into any shape. Furthermore, the surface of the sheet has irregularities similar in size to the hematite flakes, as well as irregularities that appear on the surface of the hematite flakes. Therefore, when cut sheets are placed on the surface of substrates or parts made of various materials and shapes and compressed evenly, the convex parts of the irregularities on the surface of the cut sheets come into contact with the surface of the substrate or part, and the cut sheets are bonded to the surface of the substrate or part by friction welding at the contact points, forming a bright red, non-flammable layer with excellent heat resistance on the surface of the substrate or part. The scaly hematite powder has a small average particle size of 12-15 μm and a thin thickness of 0.2-0.3 μm. Therefore, just like the flat alumina powder, by narrowing the gap between the two work rolls by nearly an order of magnitude compared to the thickness of the aggregate of scaly hematite powder covering the entire synthetic resin film, the necessary compressive stress is applied to the aggregate of scaly hematite powder, and the aggregate of hematite powder, with its flat surfaces joined together, is friction-welded to the plastically deformed synthetic resin film. As explained above, there are various types of flat powders with large aspect ratios, such as plate-like, flake-like, or scale-like shapes. These 14 types of powders have unique properties according to their material. As a result, sheets formed by a collection of flat powders joined by friction welding have properties unique to the powder. Therefore, the sheets can be used for a variety of purposes based on the unique properties of the powder.

[0010] A method for continuously producing a soft magnetic sheet that absorbs electromagnetic waves or a soft magnetic sheet that prevents interference of electromagnetic noise using flat powders made of multiple types of soft magnetic alloys from the four types of flat powders made of soft magnetic alloys described in paragraph 8, comprising: A method for continuously producing a soft magnetic sheet that absorbs electromagnetic waves or a soft magnetic sheet that prevents electromagnetic noise interference, comprising: selecting a flat powder of a plurality of types of soft magnetic alloys from among the four types of flat powders made of soft magnetic alloys described in paragraph 8, the flat powders of which have imaginary parts of complex permeability that are equal to or greater than a certain value in different frequency bands; mixing the selected flat powders made of a plurality of types of soft magnetic alloys in a predetermined ratio; using the mixed collection of flat powders made of a plurality of types of soft magnetic alloys as the flat powder described in claim 1; and sequentially carrying out all eight steps described in paragraph 8 in order;

[0011] In other words, the frequency characteristics of the imaginary part of the complex permeability differ greatly depending on the alloy composition for the four types of soft magnetic flat powder described in paragraph 8. Therefore, soft magnetic sheets used for absorbing electromagnetic waves or preventing electromagnetic noise interference use different soft magnetic flat powder materials depending on the frequency band of the electromagnetic waves to be absorbed. Therefore, if the imaginary part of the complex permeability of multiple types of soft magnetic flat powders has a magnitude equal to or greater than a certain value in different frequency bands, the absorption of electromagnetic waves depends on the magnitude of the imaginary part μ″ of the complex permeability. Therefore, if these multiple types of soft magnetic flat powders are selected from four types of soft magnetic flat powders, the selected multiple types of soft magnetic flat powders are mixed in a predetermined ratio, and the mixed soft magnetic flat powder is used as the powder described in paragraph 6. A soft magnetic sheet is produced from the mixture of multiple types of soft magnetic flat powders according to the method for producing a sheet described in paragraph 6. The soft magnetic sheet will have the effect of absorbing electromagnetic waves over a wide frequency band or preventing interference from electromagnetic noise over a wide frequency band. That is, among the four types of soft magnetic flat powders, multiple types of soft magnetic flat powders are selected from four types of soft magnetic alloys, so that the magnitude of the imaginary part of the complex permeability of the multiple types of soft magnetic flat powders is equal to or greater than a certain magnitude in different frequency bands. Furthermore, the selected multiple types of soft magnetic flat powders are mixed in a predetermined mixing ratio so that the magnitude of the imaginary part of the complex permeability of the multiple types of soft magnetic flat powders is equal to or greater than a certain magnitude in different frequency bands. The mixed flat powders are stacked with their flat surfaces facing each other, and a soft magnetic sheet is formed from the collection of multiple types of soft magnetic flat powders with their flat surfaces joined together. The imaginary part of the complex permeability characteristics of this soft magnetic sheet is the sum of the imaginary part of the complex permeability characteristics of the multiple types of soft magnetic flat powders. Therefore, the value of the imaginary part of the complex permeability has a constant magnitude over a wide frequency range. This results in a soft magnetic sheet that has the effect of absorbing electromagnetic waves over a wide frequency band or preventing interference from electromagnetic noise, which was previously impossible. For example, the imaginary part of the complex permeability of permalloy powder peaks at 3.3 MHz, while the imaginary part of the complex permeability of silicon steel peaks at 5.6 MHz. When a soft magnetic sheet is formed from a flat powder in which both types of flat powder are mixed in a 1:1 volume ratio, the imaginary part of the complex permeability of the soft magnetic sheet has a wider frequency range over which the imaginary part of the complex permeability has a certain value, for example, a value of 6 or greater, than when a soft magnetic sheet is formed from either permalloy powder or silicon steel powder alone. That is, the imaginary part of the complex permeability of permalloy powder is 6 or greater in the frequency band of 1-6.7 MHz, while the imaginary part of the complex permeability of silicon steel powder is 6 or greater in the frequency band of 3-10 MHz. In contrast, the frequency range over which the imaginary part of the complex permeability of the mixed powder is 6 or greater extends to 1-10 MHz. Furthermore, the peak value of the imaginary part of the complex permeability of the electromagnetic stainless steel flat powder is 7.5 at 5 MHz. In contrast, when a soft magnetic sheet is formed from flat powders that are a mixture of electromagnetic stainless steel flat powder, permalloy flat powder, and silicon steel flat powder in a volume ratio of 2:1:1, the imaginary part of the complex permeability of the soft magnetic sheet made from the mixture of permalloy flat powder and silicon steel flat powder drops to a valley in the frequency band of 4-6 MHz, but the electromagnetic stainless steel flat powder supplements the imaginary part of the complex permeability in this valley frequency band. As described above, when multiple types of soft magnetic flat powders are mixed in a predetermined mixing ratio so that the imaginary parts of the complex permeabilities of the multiple types of soft magnetic flat powders have imaginary parts of complex permeability that are equal to or greater than a certain magnitude in different frequency bands, and the mixed multiple types of soft magnetic flat powders are used as the powder described in paragraph 6, and a soft magnetic sheet is manufactured from the mixture of multiple types of soft magnetic flat powders according to the method for manufacturing a sheet described in paragraph 6, the soft magnetic sheet becomes a soft magnetic sheet that has the effect of absorbing electromagnetic waves over a wide frequency band or preventing interference from electromagnetic noise.

[0012] The method for continuously producing a sheet made of an aggregate of flat powders in which the flat surfaces of the flat powders are joined by friction welding as described in paragraph 6 includes the steps of: The alcohol having both of the characteristics described in paragraph 6 is any one of 1-heptanol, 2-octanol, 3-pentanol, 1-octanol, and 2-ethyl-1-hexanol, and the method of using this alcohol as the alcohol described in paragraph 6 and carrying out all of the eight steps described in paragraph 6 in sequence is a manufacturing method for continuously producing a sheet made of an assembly of flat powder in which the flat surfaces of the flat powder are joined together by friction welding.

[0013] In other words, there are five types of alcohols that have both the first characteristic of a viscosity of 6-10 mPa·sec at 20°C described in paragraph 6 and the second characteristic of a boiling point below 200°C. 1-Heptanol CH3(CH2)6OH has a viscosity of 5.8 mPa·s at 20°C and a boiling point of 176°C. 2-Octanol CH3(CH2)5CH(OH)CH3 has a viscosity of 6.2 mPa·s at 20°C and a boiling point of 178°C. 3-Pentanol (C2H5)2CHOH has a viscosity of 6.5 mPa·s at 20°C and a boiling point of 116°C. 1-Octanol CH3(CH2)7OH has a viscosity of 7.3 mPa·s at 20°C and a boiling point of 194°C. 2-Ethyl-1-hexanol, CH3(CH2)3CH(C2H5)CH2OH, has a viscosity of 9.8 mPa·s at 20°C and a boiling point of 185°C. Therefore, by using any one of these five types of alcohol as an alcohol that combines the first characteristic of a viscosity of 6-10 mPa·sec at 20°C and the second characteristic of a boiling point lower than 200°C as described in paragraph 6, and performing all eight steps described in paragraph 6 in sequence, a sheet made of an aggregate of flat powder in which the flat surfaces of the flat powder are joined by friction welding can be continuously produced. Furthermore, because the boiling points of these five types of alcohol are lower than 200°C, the temperature to which the two work rolls of the multi-high rolling mill are heated in the fourth step described in paragraph 6 is low, making the processing of the fourth step easier.

[0014] The method for continuously producing a sheet made of an aggregate of flat powders in which the flat surfaces of the flat powders are joined by friction welding as described in paragraph 6 includes the steps of: The synthetic resin film described in paragraph 6 is a film made of polyethylene terephthalate resin, and the solvent for dissolving the polyethylene terephthalate resin film is hexafluoro-2-propanol. Or, The synthetic resin film described in paragraph 6 is a film made of vinyl chloride resin, and the solvent for dissolving the vinyl chloride resin film is tetrahydrofuran. Or, The synthetic resin film described in paragraph 6 is a film made of polypropylene resin, and the solvent for dissolving the polypropylene resin film is toluene or xylene heated to 80°C or higher. Or, The synthetic resin film described in paragraph 6 is an acrylic resin film, and the solvent for dissolving the acrylic resin film is acetone, toluene, tetrahydrofuran, or benzene. Or, The synthetic resin film described in paragraph 6 is a film made of polyethylene resin, and the solvent that dissolves the polyethylene resin film is toluene, xylene, or 1,1,2-trichloroethane heated to 80°C or higher. Or, The synthetic resin film described in paragraph 6 is a film made of polycarbonate resin, and the solvent for dissolving the polycarbonate resin film is acetone, toluene, tetrahydrofuran, or benzene. A method for continuously producing a sheet consisting of a collection of flat powder in which the flat surfaces of the flat powder are joined together by friction welding, is provided by using any one of these six types of synthetic resin film and a solvent that dissolves the synthetic resin film as the synthetic resin film and solvent for the synthetic resin film described in paragraph 6, and continuously carrying out all of the eight processes described in paragraph 6.

[0015] In other words, there are six types of synthetic resin films that are commonly used: polyethylene terephthalate resin film, vinyl chloride resin film, polypropylene resin film, acrylic resin film, polyethylene resin film, and polycarbonate resin film. These six types of synthetic resin films can be dissolved in commonly used solvents, as described below. A film made of polyethylene terephthalate resin dissolves in hexafluoro-2-propanol (CF3)2CHOH, which has a boiling point of 58°C at room temperature. Hexafluoro-2-propanol has a density of 1.60 g / cm 3 It has a relatively high density for an alcohol. On the other hand, its viscosity at 20°C is relatively low at 1.65 mPa·sec. Therefore, in the sixth step of paragraph 6, when the sheet that has been processed in the fourth step is continuously transported through the solvent, the load on the lightweight sheet is small. Therefore, as the sheet continues to move through the solvent, the dissolution phenomenon in which the synthetic resin film that makes up the sheet dissolves in the solvent continues. Furthermore, because its boiling point is low at 58°C, the heating temperature of the heat treatment device is low in the eighth step of paragraph 6. At room temperature, a film made of vinyl chloride resin dissolves in tetrahydrofuran (CH2)4O, which has a boiling point of 65°C. Tetrahydrofuran has a density of 0.89 g / cm 3 Its viscosity at 25°C is extremely low at 0.48 mPa·sec. Therefore, in the sixth step of paragraph 6, when the sheet that has been processed in the fourth step is continuously transported through the solvent, the load on the lightweight sheet is small, and as the sheet continues to move through the solvent, the dissolution phenomenon in which the synthetic resin film that makes up the sheet dissolves in the solvent continues. In addition, because its boiling point is low at 65°C, the temperature rise temperature of the heat treatment device in the eighth step of paragraph 6 is low. Films made of polypropylene resin dissolve in toluene (C6H5CH3) or xylene (C6H4(CH3)2) heated to 80°C or higher. Toluene has a density of 0.87 g / cm 3Its low viscosity at 20°C is 0.59 mPa·sec. Therefore, in the sixth step of paragraph 6, when the sheet that has been processed in the fourth step is continuously transported through the solvent, the load on the lightweight sheet is small, and as the sheet continues to move through the solvent, the dissolution phenomenon in which the synthetic resin film that makes up the sheet dissolves in the solvent continues. In addition, because its boiling point is low at 111°C, the heating temperature of the heat treatment device is low in the eighth step of paragraph 6. Orthoxylene C6H4(CH3)2 has a density of 0.88 g / cm 3 Its viscosity at 25°C is as low as 0.76 mPa·sec. Therefore, in the sixth step of the sixth paragraph, when the sheet that has been processed in the fourth step is continuously transported through the solvent, the load on the lightweight sheet is small, and as the sheet continues to move through the solvent, the dissolution phenomenon in which the synthetic resin film that makes up the sheet dissolves in the solvent continues to progress. In addition, because its boiling point is low at 145°C, the temperature rise temperature of the heat treatment device is low in the eighth step of the sixth paragraph. Metaxylene C6H4(CH3)2 has a density of 0.86 g / cm 3 Its viscosity at 25°C is as low as 0.58 mPa·sec. Therefore, in the sixth step of paragraph 6, when the sheet that has been processed in the fourth step is continuously transported through the solvent, the load on the lightweight sheet is small, and as the sheet continues to move through the solvent, the dissolution phenomenon in which the synthetic resin film that makes up the sheet dissolves in the solvent continues to progress. In addition, because its boiling point is low at 139°C, the temperature rise temperature of the heat treatment device is low in the eighth step of paragraph 6. Furthermore, paraxylene C6H4(CH3)2 has a density of 0.86 g / cm 3 Its low viscosity at 25°C is 0.60 mPa·sec. Therefore, in the sixth step of paragraph 6, when the sheet that has been processed in the fourth step is continuously transported through the solvent, the load on the lightweight sheet is small, and as the sheet continues to move through the solvent, the dissolution phenomenon in which the synthetic resin film that makes up the sheet dissolves in the solvent continues. In addition, because its boiling point is low at 138°C, the heating temperature of the heat treatment device is low in the eighth step of paragraph 6. Acrylic resin films are soluble in acetone, toluene, tetrahydrofuran, or benzene. Acetone (CH3)2CO has a density of 0.79 g / cm 3 Its viscosity at 20°C is extremely low at 0.32 mPa·sec. Therefore, in the sixth step of paragraph 6, when the sheet that has been processed in the fourth step is continuously transported through the solvent, the load on the lightweight sheet is small, and as the sheet continues to move through the solvent, the dissolution phenomenon in which the synthetic resin film that makes up the sheet dissolves in the solvent continues. In addition, because its boiling point is low at 57°C, the temperature rise temperature of the heat treatment device in the eighth step of paragraph 6 is low. Benzene C6H6 has a density of 0.88 g / cm 3 Its low viscosity at 20°C is 0.65 mPa·sec. Therefore, in the sixth step of paragraph 6, when the sheet that has been processed in the fourth step is continuously transported through the solvent, the load on the lightweight sheet is small, and as the sheet continues to move through the solvent, the dissolution phenomenon in which the synthetic resin film that makes up the sheet dissolves in the solvent continues. In addition, because its boiling point is low at 80°C, the heating temperature of the heat treatment device is low in the eighth step of paragraph 6. Films made of polyethylene resin dissolve in toluene, xylene, or 1,1,2-trichloroethane heated to 80°C or higher. 1,1,2-trichloroethane, CH2Cl-CHCl2, has a density of 1.44 g / cm 3 Its viscosity at 25°C is relatively low at 1.69 mPa·sec. Therefore, in the sixth step of paragraph 6, when the sheet that has been processed in the fourth step is continuously transported through the solvent, the load on the lightweight sheet is small. As the sheet continues to move through the solvent, the dissolution phenomenon in which the synthetic resin film that makes up the sheet dissolves in the solvent continues. In addition, because its boiling point is low at 114°C, the temperature rise temperature of the heat treatment device in the eighth step of paragraph 6 is low. A film made of polycarbonate resin dissolves in the above-mentioned acetone, toluene, tetrahydrofuran or benzene.

[0016] A method for cutting a sheet produced by the method described in paragraph 6 into a predetermined shape and bonding the cut sheet to a predetermined position on the surface of a substrate or a part includes the steps of: The method of claim 6, wherein the sheet is continuously produced, the sheet is cut into a predetermined shape, the cut sheet is superimposed on a predetermined position on the surface of a substrate or a part, and the entire surface of the cut sheet is uniformly compressed, whereby the convex portions of the concave and convex portions on the surface of the cut sheet come into contact with the surface of the substrate or the part on which the cut sheet is superimposed, and frictional heat is generated between the contacting portions, and the contacting portions are bonded together by the frictional heat, and the cut sheet is bonded to the predetermined position on the surface of the substrate or the part. A method of cutting a sheet produced by the method described in paragraph 6 into a predetermined shape and bonding the cut sheet to a predetermined location on the surface of a substrate or part.

[0017] In other words, a sheet made of a collection of flat powders joined by friction welding is a sheet in which the flat surfaces of micron-sized flat powders are joined together, and the thickness of the joined flat powder is less than 0.2 mm. Therefore, even if the flat powder material is a high-hardness alloy or metal oxide, the sheet can be cut. This allows for processing into sheets of various sizes and shapes. The thickness of the produced sheet is thinner than the gap between the second work rolls by the thickness of the elastically or plastically deformed synthetic resin, so the thickness of the produced sheet can be predicted in advance. Meanwhile, the surface of the cut sheet has irregularities due to the thickness of the flat powder and irregularities of the flat powder that appear on the surface. Therefore, when the cut sheet is placed at a predetermined position on the surface of a substrate or part and the entire surface of the cut sheet is evenly compressed, the convex parts of the irregularities on the surface of the cut sheet come into contact with the surface of the substrate or part. Furthermore, frictional heat is generated between the contacting parts, and this frictional heat bonds the contacting parts together. This allows the cut sheet to be bonded to a predetermined position on the surface of a substrate or part. The convex portions of the unevenness resulting from the thickness of the flat powder are composed of convex portions of the unevenness close to the size of the bonded flat powder and convex portions of the flat powder that appear on the surface of the cut sheet. Therefore, a huge number of these convex portions are formed, and the cut sheet bonds to the surface of the substrate or part through these extremely large convex portions, firmly bonding the cut sheet to the predetermined position on the surface of the substrate or part. Furthermore, frictional heat generated at the contact point on the surface of the substrate or part is generated and dissipated in a short time. Furthermore, the contact area where frictional heat is generated is extremely small. Therefore, even for substrates or parts made of materials with low heat resistance, such as synthetic resins, the cut sheet can be friction-welded to a predetermined position on the surface of the substrate or part. As a result, the cut sheet can be bonded to a predetermined position on the surface of substrates or parts made of various materials, imparting the various properties of the flat powder to the predetermined position on the substrate or part. [Brief explanation of the drawings]

[0018] [Figure 1] This is an explanatory diagram showing an enlarged schematic cross section of a group of copper flake powder in which five flat surfaces of copper flake powder are overlapped and joined together. DETAILED DESCRIPTION OF THE INVENTION

[0019] Example 1 This example is an example in which a suspension in which the flat surfaces of flat powder overlap each other via alcohol is prepared in a container according to the method described in the first and second steps of paragraph 6. In this example, copper flake powder was used as the flat powder. The particle size distribution of copper flake powder (Fukuda Metal Foil & Powder Co., Ltd. product MS-800) is such that +75μm is more than 4%, +45μm is more than 25%, and -45μm is less than 75%. For a flat powder, the particle size is large and the aspect ratio is also large. The alcohol used was 1-heptanol CH3(CH2)6OH, which has a viscosity of 5.8 mPa·s at 20°C and a boiling point of 176°C. In other words, the copper flake powder has a large average particle size and a large aspect ratio among the flat powders. Therefore, even if the number of copper flake powder layers, each with its flat surfaces bonded together, is small, a sheet consisting of a collection of flat copper flake powder layers with their flat surfaces bonded together can be formed. Therefore, the number of copper flake powder layers stacked together with the alcohol interposed is small. First, a container was prepared that was 42 cm wide, 20 cm long (corresponding to its vertical width), and 15 cm deep. Furthermore, a drawing device for drawing out the roll of fabric wrapped in synthetic resin film was installed at the top of one side of the container. Furthermore, two cylindrical rollers, each 10 cm in diameter and 42 cm long, were installed in the center of the container. The two cylindrical rollers were also installed at a height such that the synthetic resin film, as drawn from the roll of fabric wrapped in synthetic resin film, would move horizontally and then the tip of the synthetic resin film would enter the gap between the two rollers. Next, 7 kg of 1-heptanol was filled into the container, and half the volume of the lower roller of the two cylindrical rollers was immersed in 1-heptanol. Furthermore, 14 kg of copper flake powder was filled into the container. After this, the container was placed on the vibration table of a vibrator, and the vibrator was operated to apply a vibration acceleration of 2 G to the container five times consecutively in the up-down direction, the front-back direction, and the left-right direction, in that order, so that the flat surfaces of the copper flake powder were overlapped with each other via the 1-heptanol. Note that the 14 kg of copper flake powder was placed in a 1-heptanol-filled container with a density of 8.96 g / cm of copper. 3 The volume calculated by this method is equivalent to 0.19 times the volume of 1-heptanol. Therefore, half the volume of the lower roller is immersed in 1-octanol.

[0020] Example 2 In this example, the suspension prepared in Example 1 is applied to one side of a synthetic resin film according to the method described in the third step of paragraph 6, and the synthetic resin film is continuously fed out of the gap between the two cylindrical rollers prepared in Example 1 at a speed equivalent to the peripheral speed at which the two cylindrical rollers rotate. For this purpose, a roll of synthetic resin film was set in a synthetic resin film roll drawing device installed in the container used in Example 1, and the synthetic resin film was continuously drawn out from the roll at a speed equivalent to the peripheral speed of the rotation of the two cylindrical rollers. A polyethylene terephthalate resin film having a thickness of 5.0 μm and a width of 40 cm was used as the synthetic resin film. The gap between the two cylindrical rollers was set to 20 μm. In other words, the 1-heptanol adsorbed on the copper flake powder having a thickness of 1 μm formed a suspension having a thickness of 3 μm, and the gap between the two cylindrical rollers was set so that this suspension was stacked in five layers and adhered to the polyethylene terephthalate resin film. Next, the tip of the polyethylene terephthalate resin film pulled out from the pull-out device is inserted into the gap between two cylindrical rollers, which are rotated at a rotation speed of one rotation per 20 seconds, and the polyethylene terephthalate resin film with the suspension adhered to one side of it is continuously fed out of the gap between the two cylindrical rollers at the same speed as the polyethylene terephthalate resin film is pulled out from the roll.

[0021] Example 3 In this example, a sheet in which a collection of copper flake powder joined by friction welding covers the entire surface of one side of a polyethylene terephthalate resin film is continuously fed from the gap between the second work rolls at a speed equivalent to the peripheral speed of the second work rolls, according to the method described in the fourth step of paragraph 6. To this end, a 12-high rolling mill (e.g., a prototype mill manufactured by Nippon Cross Rolling Co., Ltd.) was first prepared. The two work rolls were 42 cm wide and 3 cm in diameter, with a gap of 7 μm. The work rolls rotated in opposite directions at a peripheral speed of 20 seconds per revolution and were heated to 204°C, 10°C higher than the boiling point of 1-octanol. Next, the leading edge of the polyethylene terephthalate resin film that had been processed in Example 2 was inserted into the gap between the two work rolls. The leading edge of the polyethylene terephthalate resin film was drawn into the gap between the two work rolls, and a compressive stress corresponding to the size of the gap between the two work rolls was continuously applied to the polyethylene terephthalate resin film. As a result, a collection of copper flake powder, with the flat surfaces of the copper flake powder overlapping each other, is joined by friction welding over the entire surface of one side of the deformed polyethylene terephthalate resin film, and the collection of copper flake powder joined by friction welding forms a sheet that covers the entire surface of one side of the polyethylene terephthalate resin film, and is continuously fed out from the gap between the two work rolls at a speed equivalent to the peripheral speed of the two work rolls.

[0022] Example 4 This example is an example for analyzing the sheet produced in Example 3. For this purpose, the leading end of the sheet produced in Example 3 was cut to a length of 40 cm, and the structure of the sheet was analyzed. The cross section of the cut sheet was observed using an electron microscope. An ultra-low accelerating voltage SEM from JFE Techno-Research Corporation was used as the electron microscope. This device is capable of surface observation at ultra-low accelerating voltages starting from 100 volts, and has the advantage of being able to directly observe the surface of a sample without forming a conductive coating on the sample. The sheet was 7.0 μm thick. Next, secondary electron beams between 900-1000 volts of the reflected electron beam from the cross section were extracted and image-processed. Five thin, flat powder particles were stacked on one side of a 2 μm-thick organic sheet, forming a thickness of 5 μm, and the collection of flat powder particles covered the entire surface of the organic sheet. Furthermore, the energy and intensity of the characteristic X-rays were image-processed to analyze the elements that make up the flat powder. As a result, the flat powder was found to be copper. Therefore, the sheet created consisted of five copper flake powder flat surfaces that were stacked and bonded together, and the collection of copper flake powder covered the entire surface of a polyethylene terephthalate resin film that had been plastically deformed to a thickness of 2 μm.

[0023] Example 5 This example is an example in which, according to the method described in the fifth and sixth steps of paragraph 6, a sheet consisting of a collection of copper flake powder produced in Example 3 covering the entire surface of one side of a polyethylene terephthalate resin film is transferred through a solvent that dissolves polyethylene terephthalate resin, dissolving the polyethylene terephthalate resin film and producing a sheet consisting of a collection of copper flake powder. The solvent used to dissolve the polyethylene terephthalate resin film was hexafluoro-2-propanol (CF3)2CHOH. Hexafluoro-2-propanol is one of the few solvents that can dissolve many crystalline polymers, with a boiling point of 58°C and a density of 1.60 g / cm3. 3 The polyethylene terephthalate resin is mixed with water and dissolved in methanol. Hexafluoro-2-propanol is an expensive solvent. Therefore, the liquid mixture of the polyethylene terephthalate resin solution and hexafluoro-2-propanol remaining in the container after the sixth step is heated to the boiling point of hexafluoro-2-propanol to vaporize the hexafluoro-2-propanol, and the remaining polyethylene terephthalate resin is reused. The vaporized hexafluoro-2-propanol is also recovered and reused. First, prepare a container with four cylindrical rollers as described in the fifth step of paragraph 6. The container was 42 cm wide, 25 cm long (equivalent to its vertical width), and 10 cm deep. Four cylindrical rollers, each 3 cm in diameter and 42 cm long, were placed parallel to each other and spaced apart in the following positions: The center of the first roller was positioned 3 cm from one side of the container and at the top of the container, extending 1.5 cm beyond the container. The center of the second roller was positioned 6 cm from one side of the container and 2 cm from the bottom. The center of the third roller was positioned 6 cm from the other side of the container opposite the second roller, and 2 cm from the bottom of the container, the same as the second roller. The fourth roller was positioned at the top of the container, like the first roller, with its center 3 cm away from the other side of the container opposite the first roller, and it extended outside the container by 1.5 cm in height, the height of the fourth roller. Next, 7.35 liters of hexafluoro-2-propanol was filled into the container so that the second roller and the third roller were immersed in the hexafluoro-2-propanol, and the container was filled with an amount that formed a depth of 7 cm from the bottom of the container. Furthermore, the leading edge of the sheet prepared in Example 3 is brought into contact with the top of the first roller, and as the leading edge of the sheet moves, the leading edge of the sheet moves along the side of the first roller near 1 / 4 of the way. Then, the leading edge of the sheet changes its direction of movement downward and moves to be immersed in the solvent. Then, the leading edge of the sheet moves along the side of the second roller near 1 / 4 of the way. Then, the leading edge of the sheet changes its direction of movement parallel to the bottom of the container and moves through the solvent, coming into contact with the side of the third roller. Because the rotation direction of the third roller is the same as that of the second roller, the leading edge of the sheet that has come into contact with the side of the third roller moves along the side of the third roller near 1 / 4 of the way. Then, the leading edge of the sheet changes its direction of movement upward and moves forward, rising from the solvent and coming into contact with the side of the fourth roller. Because the rotation direction of the fourth roller is opposite to that of the third roller, the leading edge of the sheet that has contacted the side of the fourth roller contacts the fourth roller and moves along the side surface approximately 1 / 4 of the way around the fourth roller, after which the leading edge of the sheet changes direction to contact the uppermost part of the first roller of the container newly added in the seventh step and having the same configuration as the new container, and moves at a speed equivalent to the peripheral speed of the second work roll. By treating the sheet in this new container, the sheet continuously moves through the solvent, and the dissolution phenomenon in which the polyethylene terephthalate resin film that constitutes the sheet dissolves in the solvent continues, and the polyethylene terephthalate resin film dissolves in the solvent.

[0024] Example 6 This example is an example in which the sheet prepared in Example 5 is continuously moved through hexafluoro-2-propanol according to the method described in the seventh step of paragraph 6, and a sheet is continuously produced in which a solution of polyethylene terephthalate resin film slightly adhering to the sheet is dissolved in hexafluoro-2-propanol. To this end, a container identical to the one used in Example 5 and containing four cylindrical rollers was prepared. Furthermore, as in Example 5, 7.35 liters of hexafluoro-2-propanol was filled into the container, and the second roller and the third roller were immersed in hexafluoro-2-propanol. Thereafter, as in Example 5, the sheet was continuously moved in hexafluoro-2-propanol, and the solution of the polyethylene terephthalate resin film slightly adhering to the sheet was dissolved in the filled solvent. Furthermore, the sheet was moved toward the entrance of the heat treatment device described in the eighth step of paragraph 6 at a speed equivalent to the peripheral speed of the second work roll.

[0025] Example 7 This example is an example in which the sheets produced in Example 6 are continuously passed through a heat treatment device according to the method described in the eighth step of paragraph 6, the hexafluoro-2-propanol adhering to the sheets is vaporized, and sheets consisting of a collection of copper flake powder joined by friction welding are continuously produced. For this purpose, a heat treatment device is prepared that is exposed to a nitrogen atmosphere and heated to 62° C. Thereafter, the sheet produced in Example 6 is continuously passed through the heat treatment device, and the sheet fed out from the heat treatment device is wound up by a winder that rotates at the same rotation speed as the two work rolls described above. The tip of the sheet delivered from the heat treatment device was cut to a length of 40 cm, and the cross section of the cut sheet was observed using the electron microscope used in Example 4. It was found that the sheet was a collection of copper flake powder in which five copper flake powder flat surfaces were overlapped and bonded together. An enlarged schematic diagram of the cross section of the sheet is shown in Figure 1. 1 is copper flake powder. Furthermore, the tensile strength of the cut sheets was tested in accordance with JIS C6515, a copper foil testing method for printed wiring boards, and was found to be 600±30 MPa. This value is greater than the tensile strength of 450 MPa for 12 μm-thick copper foil made by low-roughness rolling tough-pitch copper, demonstrating that the sheet has sufficient mechanical strength. For this reason, the sheets produced can be used as lightweight conductive or thermally conductive sheets, and the cut sheets can be used as substrates or electrodes for electrical circuits. The cut sheet was then cut into 10cm x 10cm pieces and placed on top of a 10cm x 10cm synthetic resin sheet, 0.5mm thick. Nine 6kg weights were placed evenly spaced on the surface of the overlapping sheets to bond them together. Next, the bond strength of the bonded surface was measured at a peel speed of 300mm / min in accordance with the 180-degree peel test of JIS Z0237:2022 (Test Methods for Adhesive Tapes and Adhesive Sheets). The peel force was 280mN / 50mm, indicating sufficient bond strength. This imparts the electrical and thermal conductivity of copper to the surface of the synthetic resin sheet. The soft metal flake powder is not limited to copper flake powder. Depending on the application of the sheet made of a collection of soft metal flake powder, soft metal flake powder made of gold powder, silver powder, tin powder, zinc powder, or aluminum powder as described in paragraph 8 can be selected.

[0026] Example 8 This example, like Example 1, is an example in which a suspension in which the flat surfaces of flat powder overlap with each other via alcohol is prepared in a container according to the method described in the first and second steps of paragraph 6. In this example, three types of soft magnetic flat powder were used as the flat powder. These three types of soft magnetic flat powder have peak values ​​of the imaginary part of their complex permeability at different frequencies. The flat surfaces of these three types of soft magnetic flat powder are bonded together to produce a magnetic sheet consisting of an aggregate of soft magnetic flat powder. Therefore, the complex permeability of the magnetic sheet is the sum of the complex permeabilities of the three types of soft magnetic flat powder. Therefore, it is possible to absorb electromagnetic waves over a wider frequency range or prevent interference from electromagnetic noise over a wider frequency range than if each of the three types of soft magnetic flat powder were used individually. The three types of soft magnetic flat powder consist of permalloy flat powder containing 50% nickel, silicon steel flat powder containing 3% silicon, and electromagnetic stainless steel flat powder. Flat powder of permalloy made of 50% nickel (for example, a product developed by Sanyo Special Steel) has an aspect ratio of 38 and an average particle size of 14 μm. The imaginary part of the complex permeability rises sharply from around 100 MHz, reaches a peak value of 8.8 at 3.3 GHz, decreases from around 4 GHz, and reaches a value of 3.5 at 10 GHz. Therefore, in the frequency band of 1-8 GHz, the imaginary part of the complex permeability has a value of 5 or more. On the other hand, in a DC magnetic field, the initial relative permeability is 1×10 4 The maximum relative permeability is 1.4 x 10 5 It has excellent magnetic permeability characteristics, and the skin depth at 1 GHz is 5.0 μm. Soft magnetic flat powder made from silicon steel with 3% silicon (for example, a product developed by Sanyo Special Steel) has an aspect ratio of 34 and an average particle size of 9 μm. Furthermore, in contrast to the aforementioned Permalloy, the imaginary part of the complex permeability has the required magnitude in the high frequency range. That is, it gradually increases from around 10 MHz, reaches a value of 2.3 at 1 GHz, intersects with the imaginary part of the complex permeability of Permalloy at 4.7 GHz, reaches a peak value of 8.7 at 5.9 GHz, gradually decreases from around 6.3 GHz, reaches a value of 5.9 at 10 GHz, and reaches a value of 3.7 at 12 GHz. Therefore, above 4.7 GHz, the imaginary part of the complex permeability is larger than that of the aforementioned Permalloy. Soft magnetic flat powder (for example, a product developed by Sanyo Special Steel) made from electromagnetic stainless steel with 7% chromium, 1% silicon, and 1.6% aluminum added to iron has an aspect ratio of 29 and an average particle size of 12 μm. The imaginary part of the complex permeability increases sharply from around 10 MHz, reaching a value of 3.4 at 1 GHz, intersecting with the imaginary part of silicon steel with 3% silicon at 4.2 GHz, showing a peak value of 7.5 at 4.8 GHz, and gradually decreasing from around 5.5 GHz, remaining at 4.8 at 10 GHz and reaching a value of 3.1 at 12 GHz. Therefore, when three types of soft magnetic flaky powders are used - soft magnetic flaky powder made from permalloy, soft magnetic flaky powder made from silicon steel with 3% silicon, and soft magnetic flaky powder made from electromagnetic stainless steel - the characteristics of the imaginary part of the complex permeability of the three types of soft magnetic flaky powder are added together, improving the performance of absorbing electromagnetic noise in the intermediate frequency band from 2 to 8 GHz. In particular, the performance of absorbing electromagnetic noise in the frequency band from 3.3 GHz, where the imaginary part of the complex permeability of permalloy reaches its peak, to 4.8 GHz, where the imaginary part of the complex permeability of 3% silicon steel reaches its peak, is improved. Furthermore, three types of soft magnetic flat powders consisting of permalloy flat powder, silicon steel flat powder with 3% silicon, and electromagnetic stainless steel flat powder were weighed in a weight ratio of 10:9:20, mixed, and the resulting three types of soft magnetic flat powders were used as the flat powder. Therefore, the soft magnetic flat powders, in which the flat surfaces of the three types of soft magnetic flat powder randomly overlap, were friction-welded to create a magnetic sheet. Therefore, because the flat surfaces of the three types of soft magnetic flat powder appear randomly on the surface of the magnetic sheet, the complex permeability of the magnetic sheet is the sum of the complex permeabilities of the three types of soft magnetic flat powder. The average density of the mixture of the three types of soft magnetic flat powder was 7.87 g / cm, which is close to the density of electromagnetic stainless steel. 3 becomes. The alcohol used was 3-pentanol (C2H5)2CHOH, which has a viscosity of 6.5 mPa·s at 20°C and a boiling point of 116°C. The three types of soft magnetic flat powders had a flatness similar to that of the copper flake powder used in Example 1, but their average particle size was smaller than that of the copper flake powder, and their thickness was nearly half that of the copper flake powder. For this reason, 3-pentanol, with a viscosity of 6.5 mPa·s, was used as the alcohol, which has a higher viscosity than the 1-heptanol used in Example 1, which had a viscosity of 5.8 mPa·s. Since the three types of soft magnetic flat powders had a smaller average particle size than the copper flake powder, a sheet consisting of a collection of flat powders in which the flat surfaces of the three types of soft magnetic flat powders were bonded together could be formed by increasing the number of layers of soft magnetic flat powders in which the flat surfaces of the three types of soft magnetic flat powders were bonded together compared to the number of layers of copper flake powder. For this reason, 3-pentanol, which has a higher viscosity than 1-heptanol in Example 1, was used as the alcohol, and the number of layers of flat powder of the soft magnetic flat powder stacked together with 3-pentanol interposed therebetween was increased. First, as in Example 1, a container was prepared having a width of 42 cm, a length equivalent to the vertical width of 20 cm, and a depth of 15 cm. Furthermore, a drawing device for drawing out a roll of material wrapped in synthetic resin film was installed at the top of one side of the container. Two cylindrical rollers, each 10 cm in diameter and 42 cm in length, were also installed in the center of the container. The two cylindrical rollers were also installed at a height such that the synthetic resin film, drawn from the roll of material wrapped in synthetic resin film, would move horizontally and then the tip of the synthetic resin film would enter the gap between the two rollers. Next, 7 kg of 3-pentanol was filled into the container, and half the volume of the lower roller of the two cylindrical rollers was immersed in the 3-pentanol. Furthermore, three types of soft magnetic flat powders with a weight ratio of 10:9:20 were weighed out to 14 kg, and the three mixed soft magnetic flat powders were filled into the container. The container was then placed on the vibration table of the vibrator, the vibrator was operated, and a vibration acceleration of 2 G was applied to the container five times in succession in the vertical, front-back, and left-right directions, and the flat surfaces of the three types of soft magnetic flat powders were randomly stacked together through the 3-pentanol. The volume of the 14 kg mixed three types of soft magnetic flat powders converted using the average density of the mixed three types of soft magnetic flat powders was equivalent to 0.21 times the volume of the 3-pentanol. Therefore, half the volume of the lower roller was immersed in the 3-pentanol.

[0027] Example 9 In this example, similar to Example 2, the suspension prepared in Example 8 is applied to one side of a synthetic resin film according to the method described in the third step of paragraph 6, and the synthetic resin film is continuously fed out from the gap between the two cylindrical rollers prepared in Example 8 at a speed equivalent to the peripheral speed of the rotation of the two cylindrical rollers. In this example, a vinyl chloride resin film having a thickness of 5.0 μm and a width of 40 cm is used as the synthetic resin film, and a solvent having a boiling point of 65° C. and a density of 0.89 g / cm is used as the solvent for dissolving the vinyl chloride resin. 3 Tetrahydrofuran, which has a viscosity of 0.48 mPa·sec at 25°C, was used. The gap between the two cylindrical rollers was set to 19 μm. In other words, the gap between the two cylindrical rollers was set so that 1-heptanol adsorbed to the soft magnetic flat powder with a thickness of 0.5 μm would form a suspension with a thickness of 2 μm, and this suspension would be laminated in seven layers and adhere to the polyvinyl chloride resin film. A roll of vinyl chloride resin film is set in a synthetic resin film roll drawing device provided in the container used in Example 8, and the vinyl chloride resin film is continuously drawn out from the roll of vinyl chloride resin at a speed equivalent to the peripheral speed of the rotation of the two cylindrical rollers. Next, the tip of the drawn out vinyl chloride resin film is inserted into the gap between the two cylindrical rollers, and the two cylindrical rollers are rotated at a rotation speed of one rotation per 20 seconds, and the vinyl chloride resin film with the suspension adhered to one side of the vinyl chloride resin film is continuously fed out from the gap between the two cylindrical rollers at the speed at which the vinyl chloride resin film is drawn out from the roll of vinyl chloride resin.

[0028] Example 10 In this example, similar to Example 3, a sheet in which a collection of three types of soft magnetic flat powders joined by friction welding covers the entire surface of one side of a polyvinyl chloride resin film is continuously fed from the gap of the second work roll at a speed equivalent to the peripheral speed of the second work roll, according to the method described in the fourth step of paragraph 6. To this end, a 12-high rolling mill (e.g., a prototype device manufactured by Nippon Cross Rolling Co., Ltd.) was prepared, which had two work rolls with a width of 42 cm and a diameter of 3 cm, a gap of 3.5 μm, rotated in opposite directions at a peripheral speed of 20 seconds per revolution, and heated to 126°C, 10°C higher than the boiling point of 3-pentanol. Next, the leading edge of the vinyl chloride resin film that had been processed in Example 9 was inserted into the gap between the two work rolls. The leading edge of the vinyl chloride resin film was pulled into the gap between the two work rolls, and a compressive stress corresponding to the size of the gap between the two work rolls was continuously applied to the vinyl chloride resin film. As a result, the flat surfaces of the three types of soft magnetic flat powder randomly overlap one side of the deformed vinyl chloride resin film, and the flat surfaces are friction-welded together. The three types of soft magnetic flat powder joined by friction welding form a sheet covering the entire surface of one side of the vinyl chloride resin film. This sheet is then continuously fed from the gap between the two work rolls at a speed equivalent to the peripheral speed of the two work rolls. The thickness of the three types of soft magnetic flat powder is thinner than that of the copper flake powder. The hardness of the three types of soft magnetic flat powder is also higher than that of the copper flake powder. Therefore, the gap between the two work rolls was set to 4.5 μm, narrower than the gap in Example 3, and a compressive stress greater than that in Example 3 was applied to the three types of soft magnetic flat powder and the vinyl chloride resin film. The three types of soft magnetic flat powder, with their flat surfaces joined together, were then friction-welded to the plastically deformed vinyl chloride resin film.

[0029] Example 11 This example is an example in which the sheet produced in Example 10 is analyzed. For this purpose, the leading end of the sheet produced in Example 10 was cut to a length of 40 cm, and the structure of the sheet was analyzed. The cross section of the cut sheet was observed under an electron microscope, as in Example 4. The sheet thickness was 4.5 μm. Next, secondary electron beams between 900 and 1000 volts were extracted from the cross section and image processing was performed. Seven layers of 0.4-0.6 μm thick materials were laminated on one side of a 1 μm thick organic sheet, forming a thickness of 3.5 μm, covering the entire surface of the organic sheet. Therefore, the sheet created consisted of five sheets of three types of soft magnetic flat powder randomly stacked and bonded together, and the collection of these three types of soft magnetic flat powder covered the entire surface of a vinyl chloride resin film plastically deformed to a thickness of 1 μm.

[0030] Example 12 In this example, similar to Example 5, a sheet consisting of a group of three types of soft magnetic flat powders produced in Example 10 covering the entire surface of one side of a vinyl chloride resin film is moved through a solvent that dissolves vinyl chloride resin, dissolving the vinyl chloride resin film, and a sheet consisting of a group of three types of soft magnetic flat powders is produced according to the method described in the fifth and sixth steps of paragraph 6. The solvent used to dissolve vinyl chloride resin is a solvent with a boiling point of 65°C and a density of 0.89 g / cm. 3 Tetrahydrofuran (CH2)4O, which has a viscosity of 0.48 mPa·sec at 25°C, was used. First, prepare a container with four cylindrical rollers as described in the fifth step of paragraph 6. The container was 42 cm wide, 25 cm long (equivalent to its vertical width), and 10 cm deep. Four cylindrical rollers, each 3 cm in diameter and 42 cm long, were placed parallel to each other and spaced apart in the following positions: The center of the first roller was positioned 3 cm from one side of the container and at the top of the container, extending 1.5 cm beyond the container. The center of the second roller was positioned 6 cm from one side of the container and 2 cm from the bottom. The center of the third roller was positioned 6 cm from the other side of the container opposite the second roller, and 2 cm from the bottom of the container, the same as the second roller. The fourth roller was positioned at the top of the container, like the first roller, with its center 3 cm away from the other side of the container opposite the first roller, and it extended outside the container by 1.5 cm in height, the height of the fourth roller. Next, 7.35 liters of tetrahydrofuran was filled into the container so that the second roller and the third roller were immersed in tetrahydrofuran, and the container was filled with an amount of tetrahydrofuran to form a depth of 7 cm from the bottom of the container. Furthermore, the leading edge of the sheet prepared in Example 10 was brought into contact with the top of the first roller, and as the leading edge of the sheet moved, the leading edge of the sheet moved along the side of the first roller near 1 / 4 of the first roller. Then, the leading edge of the sheet changed its direction of movement downward and moved to be immersed in the solvent. Then, the leading edge of the sheet moved along the side of the second roller near 1 / 4 of the second roller. Then, the leading edge of the sheet changed its direction of movement parallel to the bottom of the container and moved through the solvent, coming into contact with the side of the third roller. Because the rotation direction of the third roller was the same as that of the second roller, the leading edge of the sheet that had come into contact with the side of the third roller moved along the side of the third roller near 1 / 4 of the third roller. Then, the leading edge of the sheet changed its direction of movement upward and continued, lifted from the solvent, and came into contact with the side of the fourth roller. Because the rotation direction of the fourth roller is opposite to that of the third roller, the leading edge of the sheet that has contacted the side surface of the fourth roller contacts the fourth roller and moves along the side surface approximately one-quarter of the way around, after which the leading edge of the sheet changes direction to contact the uppermost part of the first roller in a container having the same configuration as the new container newly added in the seventh step, and moves at a speed equivalent to the peripheral speed of the second work roll. As the sheet is treated in this new container, the sheet continues to move through the solvent, and the dissolution phenomenon in which the vinyl chloride resin film that constitutes the sheet dissolves in the solvent continues, and the vinyl chloride resin film dissolves in the solvent.

[0031] Example 13 In this example, similar to Example 6, the sheet prepared in Example 12 is continuously moved through tetrahydrofuran according to the method described in the seventh step of paragraph 6, and a sheet is continuously prepared by dissolving a solution of a vinyl chloride resin film slightly adhering to the sheet in tetrahydrofuran. For this purpose, a container identical to the one used in Example 12 and containing four cylindrical rollers was prepared. Furthermore, as in Example 12, 7.35 liters of tetrahydrofuran was filled into the container, and the second roller and the third roller were immersed in tetrahydrofuran. Thereafter, as in Example 12, the sheet was continuously moved in tetrahydrofuran, and the solution of the vinyl chloride resin film slightly adhering to the sheet was dissolved in the filled solvent. Furthermore, the sheet was moved toward the inlet of the heat treatment device described in the eighth step of paragraph 6 at a speed equivalent to the peripheral speed of the second work roll.

[0032] Example 14 In this example, similar to Example 7, the sheets produced in Example 13 are continuously passed through a heat treatment device according to the method described in the eighth step of paragraph 6, the tetrahydrofuran adhering to the sheets is vaporized, and sheets consisting of a collection of three types of soft magnetic flat powders joined by friction welding are continuously produced. For this purpose, a heat treatment device was prepared that was exposed to a nitrogen atmosphere and heated to 70° C. Thereafter, the sheets produced in Example 13 were continuously passed through the heat treatment device, and the sheets sent out from the heat treatment device were wound up by a winder that rotated at the same rotation speed as the two work rolls. The leading edge of the sheet fed out of the heat treatment device was cut to a length of 40 cm, and the cross section of the cut sheet was observed under the electron microscope used in Example 11. The sheet was made up of five layers of materials, each 0.4-0.6 μm thick, laminated together to form a thickness of 2.5 μm. Next, the electromagnetic noise absorption performance of the cut sheet was evaluated using the following method. A microstrip line, 140 mm long and 30 mm wide, with a characteristic impedance adjusted to 50 Ω, was installed on a board, and the sheet was aligned with the length of the microstrip line, with the centers of the lines coinciding, to create a noise-absorbing sheet. After this, S parameters were measured using a network analyzer (Agilent Technologies product N5230A) connected to the microstrip line. The S parameter S due to reflection was 11 and the S-parameter S due to transmission12 Therefore, the transmission loss in the microstrip line is the amount of electromagnetic wave absorption according to the following formula 1. The measurement results showed that the absorption was 8% at 1 GHz, 10% at 3.3 GHz, 9% at 4.7 GHz, 10% at 5.9 GHz, and 8% at 10 GHz. (Formula 1) Reflection amount (dB)=20log|S 11 | Transmission amount (dB)=20log|S 12 | Absorption amount (%) = (1 - |S 11 | 2 -|S 12 | 2 ) x 100 The absorption rate was 8% at 1 GHz, 10% at 3.3 GHz, 9% at 4.7 GHz, 10% at 5.9 GHz, and 8% at 10 GHz. As a result, the absorption rate was over 8% over the wide frequency band of 1-10 GHz. However, the amount of electromagnetic wave absorption was low. This is because the average particle size of the three alloys was smaller and the flatness was lower than that of the flat powder used in Example 3. The cut sheet was then cut into 10cm x 10cm pieces and placed on top of a 1mm thick, 10cm x 10cm synthetic resin sheet. Nine 6kg weights were placed evenly spaced on the surface of the overlapping sheets to bond them together. The bond strength of the bonded surfaces was then measured at a peel speed of 300mm / min in accordance with the 180° peel test of JIS Z0237:2022 (Test Methods for Adhesive Tapes and Adhesive Sheets). The peel force was 360mN / 50mm, indicating sufficient bond strength. This gives the synthetic resin sheet surface the functionality of a magnetic sheet, capable of absorbing electromagnetic waves over a wide frequency range or preventing electromagnetic noise interference over a wide frequency range. Note that the case of combining soft magnetic flat powders made of multiple types of alloys is not limited to Example 8. In other words, when flat powders are combined so that the imaginary part of the complex permeability has a constant value over a wide frequency band, a collection of flat powders in which the flat surfaces overlap and bond together will exhibit the characteristics of the imaginary part of the complex permeability, which is the sum of the characteristics of the imaginary part of the complex permeability of each flat powder, and as a result, a sheet that absorbs electromagnetic noise over a wide frequency band can be realized.

[0033] Example 15 In this example, similar to Examples 1 and 8, a suspension in which the flat surfaces of flat powder overlap each other via alcohol is prepared in a container according to the method described in the first and second steps of paragraph 6. In this example, alumina flat powder was used as the flat powder. Alumina flake powder is produced by hydrothermal synthesis. It has a large aspect ratio (average 30) and a small average particle size (9 μm) (Kawai Lime Industry Co., Ltd.'s BMF series). Therefore, the average thickness of alumina is thin (0.3 μm). Furthermore, alumina flake powder has a high Mohs hardness of around 9, depending on the purity of the alumina. Therefore, alumina flake powder does not deform under compressive stress. Therefore, narrowing the gap between the two work rolls and increasing the compressive stress applied to the alumina promotes plastic deformation of the synthetic resin film, but the alumina flake powder does not deform. Therefore, some of the alumina flat surfaces come into contact with each other, and the flat surfaces are friction-welded at the contact points. Furthermore, the small particle size of alumina increases the number of overlapping alumina flake powders and the number of stacked alumina flake powders with their flat surfaces joined together, thereby ensuring the mechanical strength of the sheet. The alcohol used was 2-ethyl-1-hexanol, which has a viscosity of 9.8 mPa·s at 20°C and a boiling point of 185°C. As mentioned above, the alumina flake powder produced by hydrothermal synthesis has a small average particle size of 9 μm. Furthermore, the alumina flake powder does not undergo plastic deformation. Therefore, by using 2-ethyl-1-hexanol, which has a relatively high viscosity, as the alcohol that makes up the suspension, it is possible to stack a larger number of alumina flake powders than when using copper flake powder or soft magnetic flake powder. First, as in Examples 1 and 8, a container was prepared having a width of 42 cm, a length equivalent to the vertical width of 20 cm, and a depth of 15 cm. Furthermore, a drawing device for drawing out a roll of material wrapped in a synthetic resin film was installed at the top of one side of the container. Two cylindrical rollers, each 10 cm in diameter and 42 cm long, were installed in the center of the container. The two cylindrical rollers were also installed at a height such that the synthetic resin film, drawn from the roll of material wrapped in the synthetic resin film, would move horizontally and then the leading edge of the synthetic resin film would enter the gap between the two rollers. Next, 7 kg of 2-ethyl-1-hexanol was filled into the container, and half the volume of the lower roller of the two cylindrical rollers was immersed in the 2-ethyl-1-hexanol. Furthermore, 6 kg of flat alumina powder was weighed and filled into the container. The container was then placed on the vibration table of the vibrator, and the vibrator was operated. A vibration acceleration of 2 G was applied to the container five times in succession in the vertical, front-back, and left-right directions, and the flat surfaces of the flat alumina powder were randomly stacked together via the 2-ethyl-1-hexanol. The volume occupied by the 6 kg of flat alumina powder was equivalent to 0.21 times the volume of the 2-ethyl-1-hexanol. Therefore, half the volume of the lower roller was immersed in the 2-ethyl-1-hexanol.

[0034] Example 16 In this example, similarly to Examples 2 and 9, the suspension prepared in Example 15 is applied to one side of a synthetic resin film according to the method described in the third step of paragraph 6, and the synthetic resin film is continuously fed out from the gap between the two cylindrical rollers prepared in Example 15 at a speed equivalent to the peripheral speed of the rotation of the two cylindrical rollers. In this example, a polypropylene resin film having a thickness of 5.0 μm and a width of 40 cm is used as the synthetic resin film, and a polypropylene resin having a boiling point of 138°C and a density of 0.86 g / cm is used as the solvent for dissolving the polypropylene resin. 3 The material used was paraxylene, C6H4(CH3)2, which has a viscosity of 0.60 mPa·sec at 25°C. The gap between the two cylindrical rollers was set to 48 μm. In other words, the gap between the two cylindrical rollers was set so that 2-ethyl-1-hexanol adsorbed on alumina powder with a thickness of 0.3 μm would form a suspension with a thickness of 3.3 μm, and this suspension would be laminated as 13 layers and adhere to the polypropylene resin film. A roll of polypropylene resin film is set in a synthetic resin film roll drawing device provided in the container used in Example 15, and the polypropylene resin film is continuously drawn out from the roll at a speed equivalent to the peripheral speed of the rotation of the two cylindrical rollers. Next, the tip of the drawn-out polypropylene resin film is inserted into the gap between the two cylindrical rollers, and the two cylindrical rollers are rotated at a rotation speed of one rotation per 20 seconds, and the polypropylene resin film with the suspension adhered to one side of the polypropylene resin film is continuously fed out from the gap between the two cylindrical rollers at the speed at which the polypropylene resin film is drawn out from the roll.

[0035] Example 17 In this example, similar to Examples 3 and 10, a sheet in which a collection of alumina flat powder joined by friction welding covers the entire surface of one side of a polypropylene resin film is continuously fed from the gap of the second work roll at a speed equivalent to the peripheral speed of the second work roll, according to the method described in the fourth step of paragraph 6. To this end, a 12-high rolling mill (e.g., a prototype device manufactured by Nippon Cross Rolling Co., Ltd.) was prepared, which had two work rolls with a width of 42 cm and a diameter of 3 cm, a gap of 4.7 μm, rotated in opposite directions at a peripheral speed of 20 seconds per revolution, and heated to 148°C, 10°C higher than the boiling point of 2-ethyl-1-hexanol. Next, the leading edge of the polypropylene resin film that had been treated in Example 16 was inserted into the gap between the two work rolls. The leading edge of the polypropylene resin film was drawn into the gap between the two work rolls, and a compressive stress corresponding to the size of the gap between the two work rolls was continuously applied to the polypropylene resin film. As a result, the flat surfaces of the alumina powder randomly overlap one side of the plastically deformed polypropylene resin film, and the flat surfaces are friction-welded together. The alumina powder aggregate, which is friction-welded together, covers the entire surface of one side of the polypropylene resin film. This sheet is then continuously fed from the gap between the two work rolls at a speed equivalent to the peripheral speed of the two work rolls. The thickness of the alumina powder is thinner than that of the soft magnetic flat powder. The hardness of the alumina powder is also higher than that of the soft magnetic flat powder. Therefore, the gap between the two work rolls was set to 4.7 μm, and a compressive stress greater than that of Example 10 was applied to the alumina powder aggregate and the polypropylene resin film. The alumina powder aggregate, with its flat surfaces joined together, was friction-welded to the plastically deformed polypropylene resin film.

[0036] Example 18 This example is an example for analyzing the sheet produced in Example 17. For this purpose, the leading end of the sheet produced in Example 17 was cut to a length of 40 cm, and the structure of the sheet was analyzed. The cross section of the cut sheet was observed under an electron microscope, as in Example 11. The sheet thickness was 4.7 μm. Next, secondary electron beams between 900 and 1000 volts were extracted from the cross section and image processing was performed. On one side of a 0.8 μm-thick organic sheet, 13 layers of 0.3 μm-thick material were laminated to form a thickness of 3.9 μm, covering the entire surface of the organic sheet. Therefore, the sheet produced consisted of 13 flat alumina powder particles randomly stacked and bonded together, and the collection of these flat alumina powder particles covered the entire surface of a polypropylene resin film plastically deformed to a thickness of 0.8 μm.

[0037] Example 19 In this example, similar to Examples 5 and 12, a sheet consisting of a polypropylene resin film entirely covered with agglomerates of alumina flat powder, as produced in Example 17, is transferred through a solvent capable of dissolving polypropylene resin, dissolving the polypropylene resin film, and producing a sheet consisting of agglomerates of alumina flat powder, according to the method described in the fifth and sixth steps of paragraph 6. The solvent used to dissolve polypropylene resin is a solvent with a boiling point of 138°C and a density of 0.86 g / cm. 3 Paraxylene C6H4(CH3)2, which has a viscosity of 0.60 mPa·sec at 25°C, was used. First, prepare a container with four cylindrical rollers as described in the fifth step of paragraph 6. The container was 42 cm wide, 25 cm long (equivalent to its vertical width), and 10 cm deep. Four cylindrical rollers, each 3 cm in diameter and 42 cm long, were placed parallel to each other and spaced apart in the following positions: The center of the first roller was positioned 3 cm from one side of the container and at the top of the container, extending 1.5 cm beyond the container. The center of the second roller was positioned 6 cm from one side of the container and 2 cm from the bottom. The center of the third roller was positioned 6 cm from the other side of the container opposite the second roller, and 2 cm from the bottom of the container, the same as the second roller. The fourth roller was positioned at the top of the container, like the first roller, with its center 3 cm away from the other side of the container opposite the first roller, and it extended outside the container by 1.5 cm in height, the height of the fourth roller. Next, 7.35 liters of paraxylene was filled into the container so that the second roller and the third roller were immersed in paraxylene, and the container was filled with an amount that formed a depth of 7 cm from the bottom of the container. Furthermore, the leading edge of the sheet prepared in Example 17 was brought into contact with the top of the first roller, and as the leading edge of the sheet moved, the leading edge of the sheet moved along the side of the first roller near 1 / 4 of the first roller. Then, the leading edge of the sheet changed its direction of movement downward and moved to be immersed in the solvent. Then, the leading edge of the sheet moved along the side of the second roller near 1 / 4 of the second roller. Then, the leading edge of the sheet changed its direction of movement parallel to the bottom of the container and moved through the solvent, coming into contact with the side of the third roller. Because the rotation direction of the third roller was the same as that of the second roller, the leading edge of the sheet that had come into contact with the side of the third roller moved along the side of the third roller near 1 / 4 of the third roller. Then, the leading edge of the sheet changed its direction of movement upward and continued, lifted from the solvent, and came into contact with the side of the fourth roller. Because the rotation direction of the fourth roller is opposite to that of the third roller, the leading edge of the sheet that has contacted the side of the fourth roller contacts the fourth roller and moves along the side approximately 1 / 4 of the way around the fourth roller, after which the leading edge of the sheet changes direction to contact the uppermost part of the first roller in a container having the same configuration as the new container newly added in the seventh step, and moves at a speed equivalent to the peripheral speed of the second work roll. As a result of this treatment of the sheet in the new container, the sheet continues to move through the solvent, and the dissolution phenomenon in which the polypropylene resin film that constitutes the sheet dissolves in the solvent continues, and the polypropylene resin film dissolves in the solvent.

[0038] Example 20 In this example, similar to Examples 6 and 13, the sheet prepared in Example 19 is continuously moved through paraxylene according to the method described in the seventh step of paragraph 6, and a sheet is continuously produced in which a solution of polypropylene resin film slightly adhering to the sheet is dissolved in paraxylene. For this purpose, a container identical to the one used in Example 19 and containing four cylindrical rollers was prepared. Furthermore, as in Example 19, 7.35 liters of paraxylene was filled into the container, and the second roller and the third roller were immersed in paraxylene. Thereafter, as in Example 19, the sheet was continuously moved in paraxylene, and the solution of the polypropylene resin film slightly adhering to the sheet was dissolved in the filled solvent. Furthermore, the sheet was moved toward the inlet of the heat treatment device described in the eighth step of paragraph 6 at a speed equivalent to the peripheral speed of the second work roll.

[0039] Example 21 This example, like Examples 7 and 14, is an example in which the sheets produced in Example 13 are continuously passed through a heat treatment device according to the method described in the eighth step of paragraph 6, the paraxylene adhering to the sheets is vaporized, and sheets consisting of a collection of flat alumina powder joined by friction welding are continuously produced. For this purpose, a heat treatment device was prepared that was exposed to a nitrogen atmosphere and heated to 70° C. Thereafter, the sheets produced in Example 20 were continuously passed through the heat treatment device, and the sheets sent out from the heat treatment device were wound up by a winder that rotated at the same rotation speed as the two work rolls. The leading edge of the sheet fed out of the heat treatment device was cut to a length of 40 cm, and the cross section of the cut sheet was observed under the electron microscope used in Example 18. The sheet was made up of 13 layers of material, each 0.3 μm thick, laminated together to form a thickness of 3.9 μm. The cut sheet was allowed to drop from a height of 2m five times, but it did not deform or break. This indicates that the flat alumina powder particles are bonded together with a certain strength, giving the sheet a certain level of strength. As mentioned in paragraph 9, alumina is 14-15It is an excellent insulator with a high resistivity of Ω·cm, a high breakdown voltage of 10-15 kV / mm, and a dielectric constant of 9.5-9.7 at 1 MHz. It also has a high Mohs hardness of 9 and is heat resistant to temperatures exceeding 1500°C. Furthermore, the thermal conductivity of alumina is 23-36 W / mK, which is one-tenth of the thermal conductivity of copper (386 W / mK), providing thermal insulation. For example, if a sheet made of alumina flake powder joined by friction welding measures 100 cm x 100 cm and is 3.9 μm thick, the resistance of the sheet made of alumina flake powder will be 2.4 x 10 17 Ω. For this reason, sheets made with alumina flake powder have extremely high insulation resistance. The sheets can also be used as high-temperature fireproof insulation sheets, and as lining and sealing materials for industrial furnaces such as heating furnaces and baking furnaces. The cut sheet was then cut into 10cm x 10cm pieces and placed on top of a 10cm x 10cm copper sheet, 0.5mm thick. Nine 10kg weights were placed evenly spaced on the surface of the overlapping sheets to bond them together. The bond strength of the bonded surfaces was then measured at a peel speed of 300mm / min in accordance with the 180° peel test of JIS Z0237:2022 (Test Methods for Adhesive Tapes and Adhesive Sheets). The peel force was 380mN / 50mm, indicating sufficient bond strength. This provides the insulating, heat-resistant, and heat-insulating properties of alumina to the copper sheet surface. The flat powder made of metal oxide is not limited to alumina flat powder. Depending on the application of the sheet made of a collection of flat powder made of metal oxide, mica powder, glass flake powder, or hematite powder as described in paragraph 8 can be selected. [Explanation of symbols]

[0040] 1 copper flake powder

Claims

1. A method for continuously producing a sheet made of an assembly of flat powder in which flat surfaces of the flat powder are joined together by friction welding, comprises the steps of: a first step of installing in the container first work rolls consisting of two cylinders, each having the first feature that the width of the container is wider than the width of the synthetic resin film, a second feature that a drawing device for drawing out the roll of material around which the synthetic resin film is wound is installed at an end of the container, and a third feature that first work rolls consisting of two cylinders and having the following five features are installed adjacent to each other in the vertical direction in the center of the container so as to have the length of the width of the container, and placing the container on a vibration table of a vibration exciter; the first work rolls consisting of two cylinders are installed in the container with the same width as the width of the container, the second feature that the first work rolls have the same diameter, the third feature that the gap between the two work rolls is set to a thickness obtained by adding the thickness of the synthetic resin film to a thickness for adsorbing the suspension prepared in the second step onto one side of the synthetic resin film, the fourth feature that the work rolls rotate in opposite directions at the same peripheral speed so as to complete one rotation in 15 seconds or more, and the fifth feature that the lower work roll is installed in a position where a portion of the lower work roll is constantly immersed in the suspension prepared in the second step; A second process is to put a mass of flat powder into the container, the mass being greater than the weight required for continuously manufacturing a sheet made of a mass of flat powder in which the flat surfaces of the flat powder are joined together, and use an alcohol having a first characteristic of a viscosity of 6-10 mPa·sec at 20°C and a second characteristic of a boiling point lower than 200°C, the smaller the average particle size of the flat powder, the higher the viscosity of the alcohol used, and fill the container with an amount of alcohol so that a portion of the lower work roll in the container is constantly immersed in the alcohol, and then operate a vibrator in which the container is placed, and repeatedly apply vibrations to the container in the up-down, left-right, and front-back directions, creating a suspension in the container in which the flat surfaces of the flat powder are overlapped via the alcohol, and then remove the container from the vibration table. a third step in which a roll of synthetic resin film having a width equivalent to the sheet of flat powder to be produced is set in a roll-pulp drawing device, and the synthetic resin film is continuously drawn out from the roll of synthetic resin at a speed equivalent to the peripheral speed at which the first work roll rotates; thereafter, a leading end of the drawn synthetic resin film is inserted into the gap between the first work rolls, and the synthetic resin film having the suspension adhered to one side thereof is continuously fed out of the gap between the first work rolls at the peripheral speed at which the first work roll rotates; The first feature is that the widths of the two cylindrical work rolls are the same and wider than the width of the synthetic resin film; the second feature is that the diameters of the two cylindrical work rolls are the same and are 1 / 10 or less of the width of the synthetic resin film; the third feature is that the gap between the two work rolls is set by a thickness that is thinner than the thickness of the aggregate of flat powder whose flat surfaces are joined together plus the thickness of the synthetic resin film; the fourth feature is that the two work rolls rotate in opposite directions at the same rotational speed as the first work roll; and the suspension is formed by A multi-stage rolling mill having a second work roll consisting of two cylinders and also having a fifth feature that the two work rolls are heated to a temperature 10°C higher than the boiling point of the alcohol to be used is prepared in advance, and the leading end of the synthetic resin film that has been treated in the third step is inserted into the gap between the second work rolls, whereby the leading end of the synthetic resin film is drawn into the gap between the second work rolls, and the synthetic resin film is continuously subjected to a compressive stress according to the size of the gap between the second work rolls. At this time, first, a compressive stress is applied uniformly to one side of the synthetic resin film. The alcohol evaporates from the suspension that has adhered to the synthetic resin film, and the flat surfaces of the flat powder deposit over the entire surface of one side of the synthetic resin film, overlapping with each other, and one side of the synthetic resin film is covered with the cluster of flat powder. Next, compressive stress begins to be applied to the cluster of flat powder and the synthetic resin film, and first the surface layer of the cluster of flat powder collapses, and the surface layer of the cluster of flat powder that has deposited on the edge of the synthetic resin film collapses as the cluster of flat powder that makes up the surface layer moves to the edge and the flat surfaces at the edge overlap with each other, and the cluster of flat powder that has deposited other than the edge collapses. The surface layer of the collection moves rearward of the gap between the second work rolls. Further, the compressive stress is applied to the collection of flat powder, and the gap between the overlapping flat surfaces of the flat powder gradually narrows. When the flat surfaces come into direct contact with each other, frictional heat is generated on the flat surfaces, and the overlapping flat surfaces are bonded together by the frictional heat, forming a collection of flat powder in which the flat surfaces of the flat powder are directly bonded together. Furthermore, the synthetic resin film is elastically or plastically deformed, and the entire surface of one side of the elastically or plastically deformed synthetic resin film isa fourth step in which the collection of flat powders whose flat surfaces are joined together are joined by friction welding, and the collection of flat powders joined by friction welding covers the entire surface of one side of the synthetic resin film, and the resulting sheet is continuously fed from the gap between the second work rolls at a speed corresponding to the peripheral speed of the second work rolls; A new container is prepared in advance, which has both a first feature that the width of the container is wider than the width of the synthetic resin film, and a second feature that four freely rotating cylindrical rollers having the same length and diameter are installed in the container parallel to each other and spaced apart, the length of the width of the container, and the solvent in which the synthetic resin film dissolves is filled into the new container in an amount that allows a second roller and a third roller of the four cylindrical rollers to be constantly immersed in the solvent. The four cylindrical rollers are arranged in the new container by setting the first roller at a position corresponding to the height at which the top of the first roller contacts the sheet discharged from the nip of the second work roll in the fourth step, and at a position 1 cm or more away from one side of the new container. a fifth step of arranging the four rollers in the new container according to the above positions for the four rollers, placing a second roller at a position that is farther from one side of the new container by the size of the first roller compared to the position of the first roller and at a position that is farther from the bottom of the new container by 1 cm or more, placing a fourth roller at a position that is farther from the other side of the new container by 1 cm or more and at a position where the top of the fourth roller is at the same height as the top of the first roller, and placing a third roller at a position that is farther from the other side of the new container by the size of the fourth roller compared to the position of the fourth roller and at the same position as the second roller that is farther from the bottom of the new container by 1 cm or more; In the fourth step, the leading edge of the sheet fed out from the gap between the second work rolls comes into contact with the top of the first roller, and as the leading edge of the sheet moves, the leading edge of the sheet moves along the side of the first roller near one-quarter of the way, after which the leading edge of the sheet changes its moving direction downward and moves and is immersed in the solvent, and further comes into contact with the side of the second roller, and as the leading edge of the sheet moves, the leading edge of the sheet moves along the side of the second roller near one-quarter of the way, after which the leading edge of the sheet changes its moving direction to a direction parallel to the bottom of the new container and moves through the solvent, and comes into contact with the side of the third roller, and as the leading edge of the sheet moves further, the leading edge of the sheet moves along the side of the third roller near one-quarter of the way a sixth step in which the sheet moves upward and moves forward, and after being pulled up from the solvent, comes into contact with the side surface of the fourth roller; furthermore, as the leading edge of the sheet moves, the leading edge of the sheet moves along the side surface of approximately 1 / 4 of the fourth roller, and then the leading edge of the sheet changes direction of movement so as to come into contact with the uppermost part of the first roller of a container newly added in the seventh step and having the same configuration as the new container, and moves at a speed equivalent to the peripheral speed of the second work roll; by treating the sheet in this way in the new container, the sheet continuously moves through the solvent, and the dissolution phenomenon in which the synthetic resin film constituting the sheet dissolves in the solvent continues to progress, and the synthetic resin film dissolves in the solvent; a seventh step in which an additional container having the same configuration as the new container used in the fifth step is prepared in advance, and the additional container is filled with the solvent in an amount such that a second roller and a third roller of the four cylindrical rollers constituting the additional container are constantly immersed in the solvent; thereafter, the same treatment as that performed in the sixth step is repeatedly performed on the sheet that has been treated in the sixth step, and the sheet is continuously moved in the filled solvent, and any solution of the synthetic resin film that has slightly adhered to the sheet is dissolved in the filled solvent; thereafter, the sheet is moved toward the entrance of a heat treatment device used in the eighth step at a speed equivalent to the peripheral speed of the second work roll; and the solvent filled in the additional container is replaced with new solvent at a predetermined cycle; an eighth step in which a heat treatment device having a first feature of being exposed to a nitrogen atmosphere and a second feature of being heated to a temperature higher than the boiling point of the solvent is prepared in advance, the sheet having been treated in the seventh step enters the heat treatment device at a speed corresponding to the peripheral speed of the second work roll, the solvent adhering to the sheet evaporates, the sheet becomes a collection of flat powder whose flat surfaces are joined by friction welding, the sheet consisting of the collection of flat powder whose flat surfaces are joined is continuously fed out of the heat treatment device at a speed corresponding to the peripheral speed of the second work roll, and the fed sheet is continuously wound up by a winder rotating at the same rotational speed as the second work roll; A method for continuously carrying out all of these eight steps is a method for continuously producing a sheet made of a collection of flat powder in which the flat surfaces of the flat powder are joined together by friction welding.

2. The method for continuously producing a sheet made of an aggregate of flat powders in which flat surfaces of the flat powders are joined together by friction welding according to claim 1 includes the steps of: The flat powder according to claim 1 is a flake powder of any one of soft metals including gold powder, silver powder, copper powder, tin powder, zinc powder, and aluminum powder, which is obtained by pulverizing a soft metal powder with a stamp mill; Or, The flat powder according to claim 1 is a flat powder made of any one of soft magnetic alloys, which are silicon steel powders containing less than 10% silicon and which are obtained by attriting atomized soft magnetic powders or reduced soft magnetic powders using a media agitation mill, permalloy powders containing 50% or less nickel, sendust powders containing half or more of the amount of aluminum added of silicon, and electromagnetic stainless steel powders containing less than 2% aluminum, Or, The flat powder according to claim 1 is a flat powder made of any one of metal oxides selected from the group consisting of alumina powder produced by hydrothermal synthesis of aluminum hydroxide, mica powder produced by finely pulverizing muscovite, glass flake powder produced by crushing molten glass expanded into a hollow shape, and hematite powder precipitated by hydrothermal treatment of yellow iron oxide in an alkaline aqueous solution, A method for continuously producing a sheet consisting of a collection of flat powder in which the flat surfaces of the flat powder are joined by friction welding, using any one of these 14 types of powder as the flat powder described in claim 1 and continuously carrying out all of the eight processes described in claim 1.

3. A method for continuously producing a soft magnetic sheet that absorbs electromagnetic waves or a soft magnetic sheet that prevents interference of electromagnetic noise by using flat powders made of multiple types of soft magnetic alloys among the flat powders made of four types of soft magnetic alloys as set forth in claim 2, comprising the steps of: A method for continuously producing a soft magnetic sheet that absorbs electromagnetic waves or a soft magnetic sheet that prevents electromagnetic noise interference, comprising: selecting a flat powder of a plurality of types of soft magnetic alloys from among the flat powders made of four types of soft magnetic alloys as described in claim 2, the flat powders of which have imaginary parts of complex permeability that are equal to or greater than a certain value in different frequency bands; mixing the selected flat powders made of a plurality of types of soft magnetic alloys in a predetermined ratio; using the mixed collection of flat powders made of a plurality of types of soft magnetic alloys as the flat powder described in claim 1; and performing all of the eight steps described in claim 1 in sequence;

4. The method for continuously producing a sheet made of an aggregate of flat powders in which flat surfaces of the flat powders are joined together by friction welding according to claim 1 includes the steps of: The alcohol having both of the characteristics described in claim 1 is any one of 1-heptanol, 2-octanol, 3-pentanol, 1-octanol, and 2-ethyl-1-hexanol, and the method of using this alcohol as the alcohol described in claim 1 and carrying out all of the eight steps described in claim 1 in sequence is a manufacturing method for continuously producing a sheet made of a collection of flat powder in which the flat surfaces of the flat powder are joined together by friction welding.

5. The method for continuously producing a sheet made of an aggregate of flat powders in which flat surfaces of the flat powders are joined together by friction welding according to claim 1 includes the steps of: The synthetic resin film according to claim 1 is a film made of polyethylene terephthalate resin, and the solvent for dissolving the polyethylene terephthalate resin film is hexafluoro-2-propanol. Or, The synthetic resin film according to claim 1 is a film made of vinyl chloride resin, and the solvent for dissolving the vinyl chloride resin film is tetrahydrofuran. Or, The synthetic resin film according to claim 1 is a film made of polypropylene resin, and the solvent for dissolving the polypropylene resin film is toluene or xylene heated to 80°C or higher. Or, The synthetic resin film according to claim 1 is a film made of an acrylic resin, and the solvent for dissolving the acrylic resin film is any one of acetone, toluene, tetrahydrofuran, and benzene. Or, The synthetic resin film according to claim 1 is a film made of polyethylene resin, and the solvent for dissolving the polyethylene resin film is any one of toluene, xylene, and 1,1,2-trichloroethane heated to 80°C or higher. Or, The synthetic resin film according to claim 1 is a film made of polycarbonate resin, and the solvent for dissolving the polycarbonate resin film is any one of acetone, toluene, tetrahydrofuran, and benzene. A method for continuously producing a sheet made of a collection of flat powder in which the flat surfaces of the flat powder are joined together by friction welding, comprising using any one of these six types of synthetic resin film and a solvent for dissolving the synthetic resin film as the synthetic resin film and solvent for dissolving the synthetic resin film described in claim 1, and continuously carrying out all of the eight processes described in claim 1.

6. A method for cutting the sheet produced by the method of claim 1 into a predetermined shape and bonding the cut sheet to a predetermined position on the surface of a substrate or a part comprises the steps of:

10. A method for continuously producing sheets by the method described in claim 1, cutting the sheets into a predetermined shape, overlapping the cut sheets at predetermined positions on the surface of a substrate or a part, and evenly compressing the entire surface of the cut sheets, thereby causing the convex portions of the unevenness on the surface of the cut sheets to come into contact with the surface of the substrate or the part on which the cut sheets are overlapped, and further generating frictional heat between the contacting parts, which bonds the contacting parts together, and bonding the cut sheets to the predetermined positions on the surface of the substrate or the part.

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