JP2007258623A - Radio wave absorbing material, radio wave absorption laminated wood, radio wave absorber, and manufacturing method thereof - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method of a radio wave absorbing material capable of realizing designed radio wave absorption characteristics precisely and obtaining improved radio wave absorption characteristics. <P>SOLUTION: The non-cured radio wave absorbing material is formed by mixing a non-cured compound resin 1 containing the radio wave absorber and a first non-cured resin, and a fiber assembly 2. A second non-cured resin is allowed to soak into the fiber assembly 2 before the mixture. In this case, assuming that the second non-cured resin is not allowed to soak in, the second non-cured resin having a volume approximated to the volume of the first non-cured resin allowed to soak into the fiber assembly 2 is preferably allowed to soak into the fiber assembly. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a fiber reinforced plastic (FRP) type radio wave absorber, a radio wave absorber laminate, a radio wave absorber, and a method of manufacturing the radio wave absorber.

In order to improve the strength of the radio wave absorber, an FRP type radio wave absorber in which fibers are included in a composite resin in which a radio wave absorbing material is mixed with a base material such as a resin, or a composite resin layer having a composite resin layered, There is an FRP type electromagnetic wave absorber in which layers made of fibers (hereinafter referred to as “fiber layers”) are alternately stacked (for example, see Patent Document 1 below).
JP 58-6200 A

  In these FRP type wave absorbers, when there is a fiber assembly part where the fibers are aggregated, at least a part of the base component of the composite resin flows out to the fiber assembly part, or the fiber aggregate part is a base material of the composite resin layer. Absorbing at least a part of the component causes an uneven distribution phenomenon in which the density of the radio wave absorbing material increases as the position near the fiber assembly portion. In particular, when the base material of the composite resin layer is an uncured resin such as a thermosetting type and the uncured resin liquefies during the curing process of the radio wave absorber, the base material component from the composite resin layer to the fiber layer The present inventor has found that the flow of is remarkable.

  FIG. 8 schematically illustrates the uneven distribution phenomenon in the radio wave absorber in which the composite resin containing the radio wave absorber material and the fiber assembly are mixed. When the fiber assembly and the uncured composite resin are mixed, Even if the phenomenon of uneven distribution of the radio wave absorbing material does not occur before the curing of FIG. 8A, after the curing of FIG. 8B, the uncured resin liquefies during the curing process and changes from the composite resin layer to the fiber assembly. The base material component flows out, and the radio wave absorbing material is unevenly distributed in the vicinity of the fiber assembly.

  FIG. 9 schematically illustrates the uneven distribution phenomenon in the radio wave absorbing laminated material. When the fiber assembly layer and the uncured composite resin layer are stacked, the uneven distribution phenomenon occurs before curing in FIG. 9A. Even if not, after curing in FIG. 5B, the uncured resin liquefies during the curing process, the base component flows out from the composite resin layer to the fiber assembly layer, and the radio wave absorbing material is unevenly distributed in the vicinity of the fiber assembly layer. End up.

  The inventor has found that the uneven distribution phenomenon causes a large difference between the designed radio wave absorption characteristics and the radio wave absorption characteristics of the manufactured radio wave absorber. That is, the inventor found that the electric constants such as complex relative dielectric constant, complex relative magnetic permeability and electrical conductivity of the composite resin change greatly as the fiber assembly is near due to the uneven distribution phenomenon. And found that the deviation from the radio wave absorption characteristics of the produced radio wave absorber becomes large.

  In particular, when there are many fibers and there are many fiber assembly parts, since the base material component flowing out from the composite resin to the fiber assembly part increases, the change in the electrical constant of the composite resin increases, and the designed radio wave absorption characteristics The divergence increases. In addition, the amount of mixing of the radio wave absorbing material is large, and due to the uneven distribution phenomenon, the distance between the radio wave absorbing material (the wave absorbing material is in the shape of particles, powder, pulverized bodies, fibers, etc.) is extremely close. Also in this case, since the change in the electric constant of the radio wave absorbing material becomes large, the deviation from the designed radio wave absorption characteristic becomes large.

  The present invention has been made in view of such a situation, the purpose of which is to achieve the designed radio wave absorption characteristics with high accuracy, the radio wave absorption material, the radio wave absorption laminate, capable of obtaining good radio wave absorption characteristics, The object is to provide a radio wave absorber and a method of manufacturing the radio wave absorber.

  Other objects and novel features of the present invention will be clarified in embodiments described later.

  In order to achieve the above object, an uncured radio wave absorber according to the first aspect of the present invention comprises an uncured composite resin including a radio wave absorber and a first uncured resin, and a fiber assembly in which fibers are aggregated. A mixture is characterized in that a second uncured resin is impregnated into the fiber assembly before mixing.

  In the uncured radio wave absorber of the first aspect, when it is assumed that the second uncured resin is not soaked, the volume approximates the volume of the first uncured resin soaked into the fiber assembly. An amount of the second uncured resin may be soaked into the fiber assembly.

  The uncured radio wave absorber of the second aspect of the present invention is a mixture of an uncured composite resin containing a radio wave absorber material and a first uncured resin, and a fiber assembly in which fibers are aggregated. Before the step, the fiber assembly is wrapped with a second uncured resin.

  In the uncured radio wave absorber of the second aspect, a volume amount approximate to the volume amount of the first uncured resin soaked into the fiber assembly when it is assumed that the second uncured resin does not wrap the material. The fiber assembly may be wrapped with the second uncured resin.

  The radio wave absorber of the third aspect of the present invention is characterized by including a radio wave absorber obtained by curing the uncured radio wave absorber.

  The method for manufacturing a radio wave absorber according to the fourth aspect of the present invention includes a step of impregnating a second uncured resin into a fiber assembly in which fibers are aggregated, and an uncured material including the radio wave absorbing material and the first uncured resin. It comprises a step of mixing a composite resin and a fiber assembly soaked with the second uncured resin to produce an uncured radio wave absorber, and a curing step of curing the uncured radio wave absorber. It is said.

  The method for manufacturing a radio wave absorber according to the fifth aspect of the present invention includes a step of wrapping a fiber aggregate in which fibers are aggregated with a second uncured resin, an uncured composite including the radio wave absorber and the first uncured resin. Characterized in that it comprises a step of mixing a resin and a fiber assembly wrapped with the second uncured resin to produce an uncured radio wave absorber, and a curing step of curing the uncured radio wave absorber. Yes.

  In the curing step of the method of manufacturing the radio wave absorber according to the fifth aspect, the second uncured resin may permeate the fiber assembly.

  The uncured radio wave absorption laminated material of the sixth aspect of the present invention is a fiber aggregate layer in which fibers are aggregated, laminated on one side or both sides of the fiber aggregate layer, and includes a radio wave absorption material and a first uncured resin. And an uncured composite resin layer in which the cured composite resin is layered, and the second uncured resin is infiltrated into the fiber assembly layer before lamination.

  In the uncured radio wave absorption laminate of the sixth aspect, when it is assumed that the second uncured resin does not soak, it approximates the volume of the first uncured resin soaked into the fiber assembly layer. A volume amount of the second uncured resin may be soaked into the fiber assembly layer. Further, the second uncured resin may be an uncured composite resin, and the uncured composite resin may be cured before lamination.

  The radio wave absorption laminated material according to the seventh aspect of the present invention is an uncured composite including a fiber aggregate layer in which fibers are aggregated and one or both sides of the fiber aggregate layer, the radio wave absorbent material and the first uncured resin. An uncured composite resin layer having a resin layer, and an uncured resin layer having a second uncured resin layered between the fiber assembly layer and the uncured composite resin layer. It is a feature.

  The radio wave absorber according to the eighth aspect of the present invention is characterized in that it includes at least one radio wave absorption laminate obtained by curing the uncured radio wave absorption laminate.

  The method for manufacturing a radio wave absorber according to the ninth aspect of the present invention includes a step of impregnating a second uncured resin into a fiber aggregate layer in which fibers are aggregated, and an uncured material including the radio wave absorbing material and the first uncured resin. Laminating a composite resin layered uncured composite resin layer on one side or both sides of a fiber assembly layer impregnated with the second uncured resin to produce an uncured radio wave absorption laminate, and the uncured And a curing step for curing the radio wave absorbing laminated material.

  In the method for manufacturing a radio wave absorber according to the tenth aspect of the present invention, an uncured composite resin containing a radio wave absorbing material and a first uncured resin is layered on one side or both sides of a fiber aggregate layer in which fibers are aggregated. A step of laminating a cured composite resin layer with an uncured resin layer formed by laminating a second uncured resin to produce an uncured radio wave absorbing laminated material, and curing to cure the uncured radio wave absorbing laminated material And a process.

  In the curing step of the radio wave absorber manufacturing method according to the tenth aspect, the second uncured resin of the uncured resin layer may soak into the fiber assembly layer.

  It should be noted that any combination of the above-described constituent elements, or a conversion of the expression of the present invention between methods or the like is also effective as an aspect of the present invention.

  ADVANTAGE OF THE INVENTION According to this invention, the radio wave absorber which can eliminate the uneven distribution phenomenon of a radio wave absorption material, can implement | achieve the designed radio wave absorption characteristic accurately, a radio wave absorption laminated material, and a wave absorber which has them as a structural member is obtained.

  Hereinafter, as the best mode for carrying out the present invention, embodiments of a radio wave absorber, a radio wave absorption laminate, a radio wave absorber, and a radio wave absorber manufacturing method will be described with reference to the drawings.

  FIG. 1 shows Embodiment 1 of the present invention. FIG. 1A shows an uncured radio wave absorber in which an uncured composite resin 1 including a radio wave absorbing material and a first uncured resin as a base material and a fiber assembly 2 in which fibers are aggregated are mixed. Prior to mixing, the second uncured resin is impregnated in the fiber assembly 2 in advance. The amount of the second uncured resin soaked is the volume amount of the first uncured resin soaked (flowed out) into the fiber assembly 2 when it is assumed that the second uncured resin is not soaked. Although it is most preferable to set the volume to the same amount, if the approximate volume amount (approximately the same amount) is used, the uneven distribution phenomenon of the radio wave absorbing material at the time of curing is prevented and the electric constant of the portion of the uncured composite resin 1 is reduced. The change can be suppressed and the deterioration of the radio wave absorption performance can also be suppressed. Here, each of the electrical constants (complex relative permittivity, complex relative permeability, conductivity) varies depending on the frequency.

  The radio wave absorbing material may be at least one selected from particles, powders, pulverized bodies, and fibers made of a magnetic body or a dielectric loss body. Examples of the magnetic material include ferrite, metal magnetic material, and metal oxide magnetic material. Examples of the dielectric loss body include carbon (carbon black, carbon graphite, carbon fiber), metal, and metal oxide.

  Examples of the uncured composite resin containing the radio wave absorbing material include those obtained by mixing the radio wave absorbing material with the first uncured resin as the base material. Examples of the first uncured resin include a thermosetting resin and an ultraviolet curable resin. An example of the thermosetting resin is an epoxy resin. An example of the ultraviolet curable resin is an epoxy resin. Furthermore, the uncured composite resin containing the radio wave absorbing material may contain at least one selected from particles made of dielectric, powder, pulverized material, and fiber. Examples of the dielectric include glass, silica, titanium, and silica sand.

  The fiber constituting the fiber assembly is preferably a dielectric fiber, and is at least one selected from glass fiber and resin fiber (polyester fiber, aramid fiber, polyparaphenylene benzobis oxazole (PBO) fiber). It may be.

  The second uncured resin may be the same material or different from the first uncured resin. However, in consideration of the curing process, it is most preferable that the curing conditions (in the thermosetting resin, the temperature applied in the curing process and the time change thereof) are the same material, and the curing conditions are preferably the same material. I can say that.

  In the case where the second uncured resin is not soaked, the volume of the first uncured resin flowing out from the uncured composite resin into the fiber assembly 2 is approximately represented by the volume of the void portion in the fiber assembly 2. The Moreover, the volume can be grasped in advance by making the fiber assembly 2 soaked with a liquid resin or the like.

  After the second uncured resin is pre-impregnated into the fiber assembly 2 as shown in FIG. 1A, the uncured composite resin 1 and the fiber assembly 2 are mixed to produce an uncured radio wave absorber. If the uncured radio wave absorber is cured in the curing process, the first uncured resin does not flow into the fiber assembly 2 even if the first uncured resin liquefies during the curing process, and the cured radio wave Even in the absorbing material, the uneven distribution phenomenon of the radio wave absorbing material does not occur as shown in FIG. Therefore, it is possible to obtain a radio wave absorber that can accurately realize a radio wave absorption characteristic as desired, and thus a radio wave absorber having this as a constituent member.

  The radio wave absorber may be backed by a radio wave reflector. Examples of the radio wave reflector include a metal plate, a conductive fiber aggregate, and an uncured radio wave reflector made by laminating a conductive fiber aggregate and an uncured resin. The conductive fiber assembly may be a conductive fiber aggregate in a mesh shape, a nonwoven fabric shape, or a unidirectional arrangement. The conductive fiber may be a metal fiber, metal oxide fiber, carbon fiber, or resin fiber formed with a metal film. The uncured resin of the uncured radio wave reflecting material may be an uncured resin different from the uncured resin of the uncured radio wave absorber. Further, the radio wave absorber may be coated.

  FIG. 2 shows a second embodiment of the present invention. FIG. 2A shows an uncured radio wave absorber obtained by mixing an uncured composite resin 1 including a radio wave absorbing material and a first uncured resin, and a fiber assembly 2 in which fibers are aggregated. The fiber assembly 2 is wrapped with the second uncured resin 3. Here, the amount of the second uncured resin 3 used for wrapping is the same as the volume amount of the first uncured resin soaked into the fiber assembly 2 when not wrapped with the second uncured resin 3. Although it is most preferable to use a volume, an approximate volume (approximately the same amount) prevents the phenomenon of uneven distribution of the radio wave absorbing material during curing and suppresses changes in the electrical constant of the uncured composite resin 1 portion. It is possible to suppress a decrease in radio wave absorption performance.

  The second uncured resin 3 wrapping the fiber assembly 2 and the first uncured resin that is the base material of the uncured composite resin 1 may be the same material or different. However, in consideration of the curing process, it is most preferable that the curing conditions (in the thermosetting resin, the temperature applied in the curing process and the time change thereof) are the same material, and the curing conditions are preferably the same material. I can say that.

  After wrapping the fiber assembly 2 with the second uncured resin 3 as shown in FIG. 2A, the uncured composite resin 1 and the fiber assembly 2 are mixed to produce an uncured radio wave absorber, If the uncured radio wave absorber is cured in the curing process, the first uncured resin does not flow out to the fiber assembly 2 even if the first uncured resin liquefies during the curing process, and the radio wave absorption after curing. Also in the material, the uneven distribution phenomenon of the radio wave absorbing material does not occur as shown in FIG.

  For example, in the case where a thermosetting uncured resin is used as the first and second uncured resins, the first uncured resin and the second uncured resin of the uncured composite resin layer are formed by heating. Liquefaction. When the second uncured resin 3 located closer to the fiber assembly 2 soaks into the fiber assembly 2, the first uncured resin does not soak into the fiber assembly 2, and the uncured composite resin portion A change in electrical constant can be suppressed, and a decrease in radio wave absorption performance can also be suppressed.

  Therefore, it is possible to obtain a radio wave absorber that can accurately realize a radio wave absorption characteristic as desired, and thus a radio wave absorber having this as a constituent member. The radio wave absorber may be backed by a radio wave reflector, or the radio wave absorber may be coated.

  The constituent materials such as the radio wave absorbing material, fiber, resin, and the like of the second embodiment are the same as those of the first embodiment, and the same or corresponding parts are denoted by the same reference numerals and detailed description thereof is omitted.

  FIG. 3 shows a third embodiment of the present invention. FIG. 3A illustrates a fiber aggregate layer 10 in which fibers are gathered in layers, and an uncured composite resin that is laminated on both sides (or one side) of the fiber aggregate layer 10 and includes a radio wave absorbing material and a first uncured resin. Although it is an uncured radio wave absorption laminate having a layered uncured composite resin layer 11 (in the form of a gel), the fiber assembly layer 10 is pre-impregnated with the second uncured resin before lamination. . Here, the amount of the second uncured resin soaked is the same volume as the amount of the first uncured resin soaked into the fiber assembly layer 10 when the second uncured resin is not soaked. However, if the volume is approximate (approximately the same amount), the uneven distribution phenomenon of the radio wave absorbing material when cured is prevented and the change in the electric constant of the uncured composite resin layer 11 is suppressed. It is possible to suppress a decrease in radio wave absorption performance.

  The fiber assembly layer 10 may be one in which a plurality of fibers exemplified in the first embodiment or yarns made of fibers are arranged in one direction. Further, it may be a woven fabric or a nonwoven fabric made of fibers or yarns made of fibers.

  In the case where the uncured radio wave absorption laminate is formed by laminating the uncured composite resin layer 11 on both sides of the fiber assembly layer 10, the thickness and electric constant of the uncured composite resin layer 11 are the same as those of the fiber assembly layer 10. It may be different on both sides.

  The second uncured resin may be an uncured composite resin. In that case, the second uncured resin may be the same material as or different from the uncured composite resin layer 11. However, in consideration of the curing process, it is most preferable that the curing conditions (in the thermosetting resin, the temperature applied in the curing process and the time change thereof) are the same material, and the curing conditions are preferably the same material. I can say that.

  As shown in FIG. 3 (A), the fiber assembly layer 10 is pre-impregnated with the second uncured resin, and then the uncured composite resin layer 11 and the fiber assembly layer 10 are laminated to form an uncured radio wave absorption laminate. After the production, if the uncured radio wave absorbing laminated material is cured in the curing process, the first uncured resin does not flow out to the fiber assembly layer 10 even if the first uncured resin is liquefied in the curing process. Even in the later radio wave absorbing laminated material, the uneven distribution phenomenon of the radio wave absorbing material does not occur as shown in FIG. Therefore, it is possible to obtain a radio wave absorption laminate material that can accurately realize the radio wave absorption characteristics as desired and, in turn, a radio wave absorber having this as a constituent member.

  In the third embodiment, when the second uncured resin soaked into the fiber assembly layer 10 is an uncured composite resin, it is preferable to cure the second uncured composite resin before lamination. Usually, the uncured composite resin layer 11 and the fiber assembly layer 10 are laminated while being pressed with a roller or the like. In this case, a part of the uncured composite resin layer 11 bites into the fiber assembly layer 10 due to pressurization, and the uncured composite resin layer 11 and the fiber assembly layer 10 cannot be peeled off easily. However, if the uncured composite resin layer 11 and the fiber assembly layer 10 are laminated after the fiber assembly layer 10 has been impregnated with the uncured composite resin, the friction between the bite uncured composite resin layer 11 and the fiber assembly layer 10 is reduced. The uncured composite resin layer 11 and the fiber assembly layer 10 are easily peeled off, and the uncured radio wave absorption laminate is not integrated. Therefore, when the second uncured resin is an uncured composite resin, it is preferable to cure the uncured composite resin soaked in the fiber assembly layer 10 before the uncured radio wave absorption laminate is laminated. As a result, when the uncured composite resin layer 11 and the fiber assembly layer 10 are laminated, the friction between the uncured composite resin layer 11 and the fiber assembly layer 10 that bites in increases, and the uncured radio wave absorption laminate is kept integral. Can do.

  When a radio wave absorber is manufactured using the radio wave absorption laminate of Embodiment 3, the radio wave absorber may be a radio wave absorber obtained by stacking and curing a plurality of the uncured radio wave absorption laminates. The uncured composite resin laminates to be laminated may all be the same, or may be a combination of materials having different thicknesses, electrical constants, and types of fiber assembly layers. Further, it may be a radio wave absorber that is cured after laminating an uncured radio wave absorption laminate and an uncured radio wave reflection material. Furthermore, a protective layer may be provided for protecting the radio wave absorbing laminated material obtained by curing the uncured radio wave absorbing laminated material and the radio wave reflecting material obtained by curing the uncured radio wave reflecting material. The protective layer may be an uncured protective layer composed of an uncured resin and a dielectric fiber assembly layer. In this case, it may be a radio wave absorber that is cured after laminating an uncured protective layer, an uncured radio wave absorption laminate, and an uncured radio wave reflection material. If necessary, the electromagnetic wave absorber can be coated.

  In the third embodiment, each constituent material such as a radio wave absorbing material, fiber, and resin may be the same as that in the first embodiment.

  FIG. 4 shows a fourth embodiment of the present invention. FIG. 4A shows a fiber aggregate layer 20 in which fibers are gathered in layers, and an uncured composite resin that is laminated on both sides (or one side) of the fiber aggregate layer 20 and includes a radio wave absorbing material and a first uncured resin. Although it is an uncured radio wave absorption laminate having a layered uncured composite resin layer 21 (gel), a second uncured resin is layered between the fiber assembly layer 20 and the uncured composite resin layer 21. The uncured resin layer 22 (gel form) is arranged and laminated. Here, the volume of the uncured resin layer 22 is the fiber assembly from the uncured composite resin layer 21 after the uncured radio wave absorption laminate is laminated (including the curing process) when the uncured resin layer is not present. The volume of the first uncured resin that permeates (flows out) into the layer 20 is preferably the same volume, but the approximate volume (approximately the same) prevents the uneven distribution of the radio wave absorbing material when cured. Thus, a change in the electric constant of the uncured composite resin layer portion can be suppressed, and a decrease in radio wave absorption performance can also be suppressed.

  The material of the fiber assembly layer and the uncured composite resin layer may be the same as in the third embodiment. The second uncured resin that forms the uncured resin layer 22 and the first uncured resin that is the base material of the uncured composite resin layer 21 may be the same material or different materials. However, in consideration of the curing process, it is most preferable that the curing conditions (in the thermosetting resin, the temperature applied in the curing process and the time change thereof) are the same material, and the curing conditions are preferably the same material. I can say that.

  As shown in FIG. 4 (A), an uncured radio wave absorbing laminate material is produced by laminating an uncured composite resin layer 21 with an uncured resin layer 22 interposed in the fiber assembly layer 20, and then preparing the uncured radio wave absorbing laminate material. If the curing process is performed in the curing process, the uncured resin layer 22 penetrates into the fiber assembly layer 20 in the curing process, and as a result, the first uncured resin does not flow out. The uneven distribution phenomenon of the electromagnetic wave absorbing material does not occur as shown in FIG.

  For example, in the case where a thermosetting uncured resin is used as the first uncured resin of the uncured composite resin layer 21 and the second uncured resin of the uncured resin layer 22, the uncured composite is heated. The first uncured resin of the resin layer 21 and the second uncured resin forming the uncured resin layer 22 are liquefied. When the second uncured resin closer to the fiber assembly layer 20 soaks into the fiber assembly layer 20, the first uncured resin does not soak into the fiber assembly layer 20, and the uncured composite resin layer portion A change in electrical constant can be suppressed, and a decrease in radio wave absorption performance can also be suppressed.

  Therefore, it is possible to obtain a radio wave absorption laminate material that can accurately realize the radio wave absorption characteristics as desired and, in turn, a radio wave absorber having this as a constituent member. The radio wave absorber may be backed by a radio wave reflector, or the radio wave absorber may be coated.

  In the case where a radio wave absorber is manufactured using the radio wave absorption laminate of the fourth embodiment, the radio wave absorber may be a radio wave absorber in which a plurality of the uncured radio wave absorption laminates are stacked and cured. The uncured composite resin laminates to be laminated may all be the same, or may be a combination of materials having different thicknesses, electrical constants, and types of fiber assembly layers. Further, it may be a radio wave absorber that is cured after laminating an uncured radio wave absorption laminate and an uncured radio wave reflection material. Furthermore, a protective layer may be provided for protecting the radio wave absorbing laminated material obtained by curing the uncured radio wave absorbing laminated material and the radio wave reflecting material obtained by curing the uncured radio wave reflecting material. The protective layer may be an uncured protective layer composed of an uncured resin and a dielectric fiber assembly layer. In this case, it may be a radio wave absorber that is cured after laminating an uncured protective layer, an uncured radio wave absorption laminate, and an uncured radio wave reflector. If necessary, the electromagnetic wave absorber can be coated.

  In the fourth embodiment, each constituent material such as a radio wave absorbing material, fiber, and resin may be the same as that in the first embodiment, and the fiber assembly layer may be the same as in the third embodiment.

  FIG. 5 is an FRP type electromagnetic wave absorber, and when there is a fiber aggregate part in which fibers are aggregated, the uneven distribution phenomenon in which the density of the radio wave absorbing material increases as it is near the fiber aggregate part, and Embodiment 4 of the present invention Thus, an example of preventing this uneven distribution will be described.

  First, FIG. 5 (A-1) before curing shows the uncured composite resin layer after lamination (including the curing process) of the uncured radio wave absorption laminate in which the uncured composite resin layer and the fiber assembly layer are laminated. FIG. 4 is a cross-sectional view of an uncured radio wave absorber in which the amount of uncured resin of the uncured composite resin is increased by the amount of the uncured resin in consideration that part of the uncured resin oozes out into the fiber assembly layer. When the uncured radio wave absorbing laminated material of FIG. 5 (A-1) before curing is cured, it is considered that it becomes FIG. 5 (A-2) after curing, but actually, after lamination (including the curing process) ), The closer to the fiber assembly layer, the more the uncured resin of the uncured composite resin layer oozes out to the fiber assembly layer, so that the cross-sectional view shown in FIG.

  That is, from the state of FIG. 5A-1 before curing (intervals L1 and L2 between the radio wave absorbing materials are substantially equal), the state of FIG. 5A-2 after curing (interval L1 ′ between radio wave absorbing materials ( <L1) and L2 ′ (<L2) are substantially equal), and after curing, the state of FIG. 5B (L2 ″ (<L2) is greater than the distance L1 ″ (≦ L1) between the radio wave absorbing materials) Even if the amount of the uncured resin in the uncured composite resin is simply exuded and increased by a considerable amount, the uneven distribution phenomenon of the radio wave absorbing material cannot be avoided.

  FIGS. 5C-1 and 5C-2 show the case of Embodiment 4 of the present invention, in which an uncured composite resin layer is laminated on both sides of the fiber assembly layer with an uncured resin layer interposed therebetween. . The volume of the uncured resin layer is the amount of uncured resin that flows out from the uncured composite resin layer to the fiber assembly layer after the uncured radio wave absorption laminate is laminated (including the curing process) in the absence of the uncured resin layer. The volume amount is the same as that of the resin or a volume amount close to it. Therefore, in the state of FIG. 5 (C-1) before curing and the state of FIG. 5 (C-2) after curing, the distances L1 'and L2' between the radio wave absorbing materials can be made almost the same.

  FIG. 6 is a fifth embodiment of the present invention, and shows a radio wave absorber including a plurality of radio wave absorption laminates described in the fourth embodiment. Before the curing of FIG. 6A, four layers of uncured radio wave absorption laminates 30 in which the uncured composite resin layer 21 is laminated with the uncured resin layer 22 interposed on both sides of the fiber assembly layer 20 are stacked, and radio waves arrive. An uncured radio wave absorber in which an uncured radio wave reflector 40 is laminated as a radio wave reflector on the opposite side of the direction, and an uncured protective layer 50 is further laminated on the radio wave arrival direction side. In the curing process, the uncured resin layer 22 in the uncured radio wave absorption laminate 30 soaks into the fiber assembly layer 20, and the uncured radio wave reflector 40, which is a laminate structure of the radio wave reflector and the uncured composite resin, or a dielectric Since the uncured composite resin of the uncured protective layer 50, which is a laminated structure of the fiber assembly layer and the uncured composite resin, also soaks into the radio wave reflector and the dielectric fiber assembly layer, the thickness of the cured radio wave absorber is It is thinner than before curing.

  In addition, in FIG. 6, although the direction of the oblique line of the fiber assembly layer which comprises an electromagnetic wave absorption laminated material differs, this has shown that the direction of a fiber differs. In the case of fibers woven in a lattice shape, it is possible to realize strength close to isotropic by laminating at an angle of 45 ° in a plane.

  FIG. 7 shows an example of radio wave absorption characteristics of a radio wave absorber backed by a radio wave reflector as described in the fifth embodiment of the present invention in FIG. In this figure, the characteristic indicated by the dotted line (without uneven distribution prevention) is as shown in FIG. 5 (A-1) to (A-2) after lamination of the uncured radio wave absorbing laminate material (including the curing process), Considering that a part of the uncured resin of the uncured composite resin layer oozes out to the fiber assembly layer, as shown in FIG. 5B, the frequency absorbing material is not considered to be unevenly distributed after curing. When designed so that the radio wave absorption characteristics are good near fc, the radio wave absorption characteristics when the radio wave absorbing material is unevenly distributed as shown in FIG. The frequency at which the radio wave absorption characteristic is maximum is shifted to a lower frequency side than fc, and the maximum value of the radio wave absorption characteristic is also reduced.

  The characteristic shown by the solid line in FIG. 7 (prevention of uneven distribution) is the uncured resin of the uncured composite resin layer after the uncured radio wave absorbing laminate material is laminated (including the curing process) as shown in FIG. In consideration of the fact that a part of the fiber oozes out into the fiber aggregate layer, an uncured composite is obtained by interposing an uncured resin layer on both sides of the fiber aggregate layer as shown in FIGS. 5 (C-1) to (C-2). This is an example in which an uncured radio wave absorption laminated material in which a resin layer is laminated is used so as to improve the radio wave absorption characteristics near the frequency fc. Actually, the radio wave absorption characteristic is good in the vicinity of the frequency fc, and a desired radio wave absorption characteristic (as previously predicted in the calculation design) is realized.

  Further, as shown in FIGS. 5A-1 and 5A-2, after the uncured radio wave absorption laminate is laminated (including the curing process), a part of the uncured resin of the uncured composite resin layer is a fiber. In the case of designing in consideration of oozing into the aggregate layer and considering that the radio wave absorbing material is unevenly distributed after curing as shown in FIG. 5 (B), the characteristic shown by the solid line in FIG. 7 (preventing uneven distribution) In some cases (when the change in the electrical constant of the composite resin due to the uneven distribution phenomenon is relatively small), the total thickness of the wave absorber is more than that when the present invention is applied. It will be thick.

  Although the embodiments of the present invention have been described above, it will be obvious to those skilled in the art that the present invention is not limited to these embodiments, and various modifications and changes can be made within the scope of the claims.

BRIEF DESCRIPTION OF THE DRAWINGS It is Embodiment 1 of this invention, Comprising: It is a typical enlarged plan view which shows before hardening after an unhardened electromagnetic wave absorber. It is Embodiment 2 of this invention, Comprising: It is a typical enlarged plan view which shows after hardening of an uncured electromagnetic wave absorber, and after hardening. It is Embodiment 3 of this invention, Comprising: It is sectional drawing which shows before hardening after an unhardened electromagnetic wave absorption laminated material, and after hardening. It is Embodiment 4 of this invention, Comprising: It is sectional drawing which shows before hardening after an unhardened electromagnetic wave absorption laminated material. FIG. 10 is an explanatory diagram for explaining an example in which the uneven distribution phenomenon of the radio wave absorbing material occurs when a fiber assembly portion is present, according to the fourth embodiment of the present invention. It is Embodiment 5 of this invention, is an example of the electromagnetic wave absorber which has multiple layers of the electromagnetic wave absorption laminated material of Embodiment 4, Comprising: It is sectional drawing which shows before hardening and after hardening. It is a radio wave absorption characteristic of a radio wave absorber backed by a radio wave reflector, and is a frequency characteristic diagram showing a comparison between the case of preventing uneven distribution and the case of preventing uneven distribution of the present invention. It is a typical enlarged plan view which shows before the hardening of the conventional uncured wave absorber, and after hardening. It is sectional drawing which shows before the hardening of the conventional uncured electromagnetic wave absorption laminated material, and after hardening.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Uncured composite resin 2 Fiber assembly 3 Uncured resin 10,20 Fiber assembly layer
11, 21 Uncured composite resin layer 22 Uncured resin layer 30 Uncured radio wave absorbing laminate 40 Uncured radio wave reflector 50 Uncured protective layer

Claims (16)

An uncured radio wave absorber in which an uncured composite resin including a radio wave absorbing material and a first uncured resin and a fiber assembly in which fibers are aggregated are mixed,
An uncured radio wave absorber, wherein a second uncured resin is impregnated into the fiber assembly before mixing.   When it is assumed that the second uncured resin is not soaked, the volume of the second uncured resin approximated to the volume of the first uncured resin soaked into the fiber assembly is the fiber. The uncured radio wave absorber according to claim 1, wherein the uncured radio wave absorber is infiltrated into the aggregate. An uncured radio wave absorber in which an uncured composite resin including a radio wave absorbing material and a first uncured resin and a fiber assembly in which fibers are aggregated are mixed,
An uncured radio wave absorber, wherein the fiber assembly is wrapped with a second uncured resin before mixing.   When it is assumed that the second uncured resin is not encased, the fiber assembly is composed of the second uncured resin in a volume amount approximate to the volume amount of the first uncured resin soaking into the fiber assembly. The uncured radio wave absorber according to claim 3, wherein the body is wrapped.   A radio wave absorber comprising a radio wave absorber obtained by curing the uncured radio wave absorber according to claim 1, 2, 3, or 4. Soaking the second uncured resin into the fiber assembly in which the fibers are assembled;
A step of mixing an uncured composite resin containing a radio wave absorbing material and a first uncured resin and a fiber assembly infiltrated with the second uncured resin to produce an uncured radio wave absorber;
And a curing step of curing the uncured radio wave absorber. Wrapping a fiber assembly in which fibers are aggregated with a second uncured resin;
A step of producing an uncured radio wave absorber by mixing an uncured composite resin containing a radio wave absorber material and a first uncured resin and a fiber assembly wrapped with the second uncured resin;
And a curing step of curing the uncured radio wave absorber.   The method of manufacturing a radio wave absorber according to claim 7, wherein in the curing step, the second uncured resin soaks into the fiber assembly. A fiber assembly layer in which fibers are assembled;
An uncured composite resin layer laminated on one side or both sides of the fiber assembly layer and layered with an uncured composite resin containing a radio wave absorbing material and a first uncured resin;
An uncured radio wave absorbing laminate material, wherein a second uncured resin is impregnated into the fiber assembly layer before lamination.   When it is assumed that the second uncured resin is not soaked, the volume of the second uncured resin approximated to the volume of the first uncured resin soaked into the fiber assembly layer is changed to the fiber. The uncured radio wave absorption laminate according to claim 9, wherein the uncured radio wave absorption laminate is infiltrated into the aggregate layer.   The uncured radio wave absorption laminate according to claim 9 or 10, wherein the second uncured resin is an uncured composite resin, and the uncured composite resin is cured before lamination. A fiber assembly layer in which fibers are assembled;
An uncured composite resin layer laminated on one side or both sides of the fiber assembly layer and layered with an uncured composite resin containing a radio wave absorbing material and a first uncured resin;
An uncured radio wave absorption laminate, wherein an uncured resin layer in which a second uncured resin is layered is disposed between the fiber assembly layer and the uncured composite resin layer.   13. A radio wave absorber comprising at least one radio wave absorbing laminate material obtained by curing the uncured radio wave absorbing laminate material according to claim 9, 10, 11 or 12. Soaking the second uncured resin into the fiber assembly layer in which the fibers are assembled;
An uncured composite resin layer formed by laminating an uncured composite resin containing a radio wave absorbing material and a first uncured resin is laminated on one or both sides of the fiber assembly layer soaked with the second uncured resin, Producing a cured radio wave absorbing laminate;
And a curing step of curing the uncured radio wave absorbing laminate material. An uncured composite resin layer in which an uncured composite resin containing a radio wave absorbing material and a first uncured resin is layered on one side or both sides of a fiber aggregate layer in which fibers are aggregated, and a second uncured resin is layered Laminating with an uncured resin layer interposed, and producing an uncured radio wave absorption laminate,
And a curing step of curing the uncured radio wave absorbing laminate material.   16. The method for manufacturing a radio wave absorber according to claim 15, wherein in the curing step, the second uncured resin of the uncured resin layer soaks into the fiber assembly layer.

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