Integrally molded body of fiber-reinforced resin layer and shielding layer, and method for producing same

Abstract

Provided is an integrally molded body having a shield layer for blocking radio waves or magnetic waves. The integrally molded body is an integrally molded body of a shielding layer and a fiber-reinforced resin layer containing reinforcing fibers and a first matrix resin, the shielding layer is a layer containing an aggregate of metal strips and a second matrix resin and shields at least one of an electric field and a magnetic field, and the metal strips are dispersed in the surface of the shielding layer to form the aggregate.

Description

Technical Field

[0001] The present invention relates to an integrally formed body of a fiber-reinforced resin layer and a shielding layer and a manufacturing method thereof. Background Art

[0002] Various studies have been conducted in the past on the technology of shielding electric fields using metals and resins.

[0003] Patent Document 1 describes a resin molded body with foil-shaped metal fragments in which fragments of a laminate of a metal foil and a plastic film are randomly adhered to each other and dispersed.

[0004] Patent document 2 describes a method for molding an electromagnetic shielding resin outer panel, in which projections and depressions are formed on a mold for molding the back of the outer panel, and aluminum foil and SMC (sheet molding compound) are overlapped on the mold, and heated and pressurized molding is performed to bond the aluminum foil to the resin.

[0005] Patent Document 3 provides a vehicle structure that simplifies the manufacturing process and has an electromagnetic wave shielding effect by providing a portion that does not follow the electromagnetic wave shielding layer in a component of a battery box having a recess.

[0006] Patent document 4 describes an electromagnetic wave shielding material, which is formed by integrally molding at least two elastomer layers composed of resin elastic fibers and a shielding layer of granular or flaky magnetic material sandwiched therebetween, thereby partially melting and solidifying the elastic fibers, and allowing the magnetic material to be wound around the elastic fibers and maintained in a semi-floating state. In the electromagnetic wave shielding material described in patent document 4, each particle or flake can move freely to a certain extent, and even if the shielding material is deformed by external load or impact, each particle or flake will not be deformed, and the shielding properties will not be reduced.

[0007] The electromagnetic shielding body described in Patent Document 5 can be formed into a highly processable electromagnetic shielding body such as a box shape by heat molding, and the conductive composition layer is not damaged during processing, and stable electromagnetic shielding performance is maintained.

[0008] The invention described in Patent Document 6 discloses an electromagnetic wave shielding composite material in which a fiber-reinforced resin molded body portion containing carbon fibers and a matrix resin and a metal layer portion are laminated.

[0009] Prior art literature

[0010] Patent Literature

[0011] Patent Document 1: Japanese Patent Application Laid-Open No. 58-84856

[0012] Patent Document 2: Japanese Patent Application Laid-Open No. 4-110278

[0013] Patent Document 3: International Publication No. 2021 / 125386

[0014] Patent Document 4: Japanese Patent Application Laid-Open No. 09-292480

[0015] Patent Document 5: Japanese Patent Application Laid-Open No. 06-021683

[0016] Patent Document 6: Japanese Patent Application Publication No. 2012-109454 Summary of the invention

[0017] Technical problem that the invention aims to solve

[0018] Vehicle structures are sometimes required to have shielding properties in order to block radio waves or magnetic waves.

[0019] However, the resin molded body with foil-like metal fragments described in Patent Document 1 is simply a resin molded body in which metal fragments are mixed, so the shielding property against electric waves or magnetic fields may be low. Generally, the higher the conductivity of a material, the higher the shielding property against electric fields or magnetic fields. In the resin molded body with foil-like metal fragments described in Patent Document 1, since the metal fragments are covered by the resin, the metal fragments do not contact each other. Therefore, the conductivity of the resin molded body described in Patent Document 1 is not high, and the shielding property against electric fields or magnetic fields is not sufficient.

[0020] Patent Document 2 attempts to shape the aluminum foil by making it concave and convex, but only discloses a molding method for a simple shape such as a flat plate. In the molding method described in Patent Document 2, even if one wants to produce an integrally molded body having a top surface and a vertical surface, such as a hat shape, the aluminum foil cannot be shaped to follow the resin.

[0021] In Patent Document 3, the electromagnetic wave shielding layer is not made to follow the constituent elements of the battery box having a recess. There is no research on the technology of making the shielding layer follow even if there are recesses or deep molded parts. In order to make the shielding layer follow the molded body with a complex shaped shape and be arranged in the molded body, the shielding layer needs to be pre-shaped and bonded to the molded body, which increases the assembly time. In addition, in order to suppress the increase in work time, when the shielding layer precursor (flat plate) and the molding material are tried to be molded simultaneously without prior shaping (pre-shaping), there is a problem of shielding layer offset.

[0022] In the electromagnetic wave shielding material described in Patent Document 4, the thin-sheet magnetic material used in the shielding layer is too heavy. In addition, since only one of the two resins is dissolved and the material is in a semi-floating state, it is not fixed.

[0023] In the electromagnetic wave shielding body described in Patent Document 5, metal fibers are used, and therefore gaps are generated.

[0024] In the composite material for electromagnetic wave shielding described in Patent Document 6, since a metal plate is used, the metal plate cannot follow when integrally molding the composite material into a molded body having a complicated shape.

[0025] Technical solutions to the problem

[0026] The present inventors have conducted intensive studies and, as a result, have found that the above-mentioned problems can be solved by the means described below, thereby completing the present invention.

[0027] 1. An integrally formed body, characterized in that:

[0028] The fiber-reinforced resin layer and the shielding layer are integrally formed, wherein the fiber-reinforced resin layer comprises reinforcing fibers and a first matrix resin.

[0029] The shielding layer is a layer including an aggregate of metal strips and a second matrix resin, and shields at least one of an electric field or a magnetic field.

[0030] The aggregate of the metal strips includes a plurality of metal strips dispersed within the surface of the shielding layer.

[0031] 2. The integrally formed body according to item 1 above, wherein:

[0032] The integrally molded body has a top surface portion and a vertical surface portion.

[0033] 3. The integrally formed body according to 1 or 2 above, wherein:

[0034] The integrally molded body has a portion that satisfies 2≤tx / ty when tx is the thickness of the shielding layer and ty is the thickness of the metal tape.

[0035] 4. The integrally formed body according to any one of 1 to 3 above, wherein:

[0036] The mass ratio W(metal) of the aggregate of the metal tapes in the shield layer is 30% or more.

[0037] 5. The integrally formed body according to any one of 1 to 4 above, wherein:

[0038] The metal belt has a width of 1 mm to 40 mm, a length of 1 mm to 100 mm, and a thickness of 100 μm or less.

[0039] 6. The integrally formed body according to any one of 1 to 5 above, wherein:

[0040] The reinforcing fibers are discontinuous fibers and are dispersed in the in-plane direction of the fiber-reinforced resin layer.

[0041] 7. The integrally formed body according to any one of 1 to 6 above, wherein:

[0042] The shielding layer has a shielding property of 10 decibels or more against an electric field or a magnetic field in at least a part of a region of a frequency range of greater than 0 MHz and not more than 3000 MHz.

[0043] 8. The integrally formed body according to any one of 1 to 6 above, wherein:

[0044] The shielding layer has a shielding property of 10 decibels or more against an electric field or a magnetic field in at least a part of a region of a frequency range of greater than 0 MHz and not more than 100 MHz.

[0045] 9. The integrally formed body according to 2 above, wherein:

[0046] The thickness ta of the vertical portion and the thickness tb of the top portion are ta≤tb.

[0047] 10. The integrally formed body according to 9 above, wherein:

[0048] When the thickness of the shielding layer in the above-mentioned vertical portion is set to txa, the thickness of the above-mentioned fiber-reinforced resin layer in the above-mentioned vertical portion is set to ta-txa, the thickness of the shielding layer in the above-mentioned top portion is set to txb, and the thickness of the above-mentioned fiber-reinforced resin layer in the above-mentioned top portion is set to tb-txb, txa≤txb and ta-txa≥tb-txb are satisfied.

[0049] 11. A vehicle structure, characterized in that:

[0050] An integrally formed body according to any one of 1 to 10 above.

[0051] 12. A component of a battery box, characterized in that:

[0052] An integrally formed body according to any one of 1 to 10 above,

[0053] The components of the battery box are arranged at the lower part of the vehicle body.

[0054] 13. A method for manufacturing an integrally formed body, characterized in that:

[0055] The integrally formed body is the integrally formed body described in any one of 1 to 10 above,

[0056] In the above method, a fiber-reinforced resin containing reinforcing fibers and a first matrix resin is laminated on a shielding layer precursor and press-molded using an upper molding die and a lower molding die.

[0057] 14. The method for producing an integrally formed body according to 13 above, wherein:

[0058] The fiber-reinforced resin and the shielding layer precursor are stacked so that the fiber-reinforced resin contacts the lower molding die, and are arranged on the lower molding die to perform press molding.

[0059] 15. The method for producing an integrally formed body according to 13 or 14 above, wherein:

[0060] The relationship between the ductility E1 of the fiber-reinforced resin and the ductility E2 of the laminate of the fiber-reinforced resin and the shielding layer precursor is 0.9<E1 / E2<50.

[0061] 16. The method for producing an integrally formed body according to any one of 13 to 15 above, wherein:

[0062] The first matrix resin and the second matrix resin are thermoplastic resins.

[0063] Effects of the Invention

[0064] By using an aggregate of metal tapes, it is possible to integrally mold the metal tape with the fiber-reinforced resin layer having a complex three-dimensional shape, and the steps of pre-shaping the metal masking layer and bonding it to the fiber-reinforced resin layer can be simplified. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] Figure 1 It is a schematic cross-sectional view of the integrally molded body.

[0066] Figure 2A This is the case when only the metal plate is shaped using a forming die. This is the state before the upper die is closed.

[0067] Figure 2B This is when the upper die is closed and pressing the metal plate.

[0068] Figure 3 It is a plan view showing an example of the shielding layer precursor 20 .

[0069] Figure 4 This is a photograph showing a part of the metal belt falling sideways.

[0070] Figure 5A This is an evaluation of the electric field shielding performance of a polypropylene resin layer having a thickness of 150 μm.

[0071] Figure 5B This is an evaluation of the electric field shielding performance when the mass ratio W of the aluminum thin film in the 150 μm-thick shielding layer composed of the aluminum thin film and the polypropylene resin is 25%.

[0072] Figure 5C This is an evaluation of the electric field shielding performance when the mass ratio W of the aluminum thin film in the 150 μm-thick shielding layer composed of the aluminum thin film and the polypropylene resin is 45%.

[0073] Figure 5D This is an evaluation of the electric field shielding performance when the mass ratio W of the aluminum thin film in the 150 μm-thick shielding layer composed of the aluminum thin film and the polypropylene resin is 65%.

[0074] Figure 5E This is an evaluation of the electric field shielding performance when the mass ratio W of the metal (aluminum) thin film in the 150 μm-thick shielding layer composed of the aluminum thin film and the polypropylene resin is 75%.

[0075] Fig. 5F This is an evaluation of the electric field shielding performance of an aluminum thin film having a thickness of 150 μm.

[0076] Figure 6 This is a schematic diagram of slitting the metal strip by pressing the lower support roll.

[0077] Figure 7 A schematic side view of slitting a metal strip using a shear knife.

[0078] Figure 8 yes Figure 7 Cross-sectional view taken along line VIII-VIII.

[0079] Fig. 9 yes Figure 8 An enlarged view of section IX.

[0080] Fig.10 It is a schematic diagram of slitting a metal strip by a combination knife method.

[0081] Fig.11 yes Fig.10 Cross-sectional view taken along line XI-XI.

[0082] Fig.12 yes Fig.11 An enlarged view of Section XII.

[0083] Fig.13 It is a cross-sectional view showing an example of the integrally formed body 1A.

[0084] Fig.14 It is an exploded perspective view showing an example of a battery box using an integrally molded body.

[0085] Fig.15 It is a perspective view showing an example of a battery tray.

[0086] Fig.16 yes Fig.15 Cross-sectional view taken along the XVI-XVI direction.

[0087] Fig.17A This is a schematic diagram for explaining the method of measuring the molding heating temperature.

[0088] Fig. 17BThis is a schematic diagram for explaining the method of measuring ductility.

[0089] Fig. 17C This is a schematic diagram for explaining the method of measuring ductility. DETAILED DESCRIPTION

[0090] Hereinafter, embodiments of the present invention will be described, but the present invention is not limited thereto.

[0091] Figure 1 1 is a schematic cross-sectional view showing a laminate 1 for forming an integrally molded body according to an embodiment of the present invention. The laminate 1 includes a fiber-reinforced resin 10 and a shielding layer precursor 20 .

[0092] [Shielding layer precursor]

[0093] like Figure 1 As shown, the shielding layer precursor 20 is a layer including an aggregate of metal strips 30 and a second matrix resin 40. The aggregate of metal strips 30 shields at least one of an electric field or a magnetic field. The metal strips 30 are dispersed inside the shielding layer precursor 20 to form an aggregate.

[0094] [Advantages of molding by using an aggregate of metal strips]

[0095] 1. Problems with existing technologies

[0096] When the metal plate and the fiber-reinforced resin layer are formed separately without using an aggregate of metal strips, the metal plate tends to break due to the unevenness of the forming mold, especially at the corners. This is because the elongation at break of the metal plate (e.g., aluminum foil) is extended to a value exceeding that at the corners. Figure 2B 1101 shows the part of the metal plate 1102 that is easy to break. In the case of forming only with a metal plate, it is necessary to set a gentle curved surface at the corner of the forming mold in advance so that the metal plate will not be damaged by the forming mold. As another method to improve the yield, in the past, there was a method of preventing breakage by Figure 2B A method of reinforcing the portion shown in 1101 by sticking a cushioning material such as tape or a reinforcing material.

[0097] In addition, not only Figure 2B Such corners tend to become wrinkles when the metal plate is deeply formed. Alternatively, the sharpness of the corners needs to be mitigated by designing the metal layer.

[0098] 2. Effect of metal strip aggregate (i)

[0099] On the other hand, when the metal tape assembly is integrally molded, even if the corner of the molding die contacts the shielding layer precursor, it is unlikely to break, and there is no need to provide a gently curved surface at the corner of the molding die.

[0100] 3. Effect of metal strip aggregate (ii)

[0101] The resin contained in the fiber-reinforced resin is a thermoplastic resin. In the case of cold press molding, if the shielding layer precursor is arranged in the molding lower mold and the fiber-reinforced resin is laminated in a manner of contacting the molding upper mold, the fiber-reinforced resin will not be cooled to the molding mold temperature until it is about to contact the molding upper mold. Therefore, it is easy to form ribs and protrusions on the fiber-reinforced resin, and the designability is also improved.

[0102] 4. Effect of metal strip aggregate (iii)

[0103] In addition, the shielding layer precursor 20 includes the second matrix resin 40. By including the second matrix resin, it is easy to form ribs, protrusions, etc. on the shielding layer when the fiber-reinforced resin 10 and the shielding layer precursor 20 are integrally molded. As in the past, when only the metal plate is provided as an independent component, the shielding layer cannot be made into a complex shape.

[0104] 5. Effect of metal strip aggregate (iv)

[0105] The shielding layer precursor 20 is preferably embedded in the integrally molded body, and the surface of the integrally molded body is consistent with the surface of the shielding layer. In this case, the interface between the integrally molded body and the shielding layer has no steps and is flat. The interface can be consistent at the top surface or the vertical surface of the integrally molded body. During the integral molding, the end of the shielding layer is buried with resin, so the defect of the end of the shielding layer can also be reduced.

[0106] [Shielding layer: Metal tape]

[0107] The metal strip preferably has a width of 1 mm to 40 mm, a length of 1 mm to 100 mm, and a thickness of 100 μm or less. If the width is 1 mm or more, it is easy to cut. The metal strip more preferably has a width of 1 mm to 40 mm, a length of 1 mm to 40 mm, and a thickness of 100 μm or less.

[0108] The width of the metal belt is more preferably 2 mm to 20 mm, further preferably 2 mm to 7 mm, and even more preferably 2 mm to 5 mm.

[0109] The length of the metal tape is more preferably 2 mm to 20 mm, further preferably 2 mm to 7 mm, and even more preferably 2 mm to 5 mm.

[0110] The thickness of the metal belt is more preferably 70 μm or less, further preferably 50 μm or less, and further preferably 30 μm or less. The lower limit of the thickness of the metal belt is preferably 12 μm or more, and more preferably 15 μm or more.

[0111] Alternatively, the metal belt may be in the form of a strip.

[0112] The weight of each metal tape is preferably 0.001 g to 0.050 g, more preferably 0.003 g to 0.040 g, and even more preferably 0.005 g to 0.020 g. Specifically, when the metal tape is 5 mm wide by 20 mm long and 30 μm thick, the weight of the metal tape is about 0.008 g.

[0113] When such light metal strips are spread, some of the metal strips do not fall sideways but stand upright. Specifically, less than 1% of the metal strips in the metal film stand upright (for example, Figure 4 Here, the metal strip is "standing upright" means that the thickness direction is oriented in the horizontal direction. The upright metal strip is flattened during the integral molding.

[0114] [Mass ratio of shielding layer: metal tape aggregate W(metal)]

[0115] The mass ratio W(metal) of the aggregate of metal strips in the shielding layer is preferably 30% or more, preferably 50% or more, and more preferably 70% or more. The mass ratio W(metal) of the aggregate of metal strips refers to the ratio of the mass of the metal strips to the mass of the entire body including not only the metal strips and the second matrix resin but also other additives.

[0116] Regarding the method for determining the mass ratio W(metal), when the second base resin contained in the shielding layer is a polypropylene resin, the shielding layer is burned in a furnace at 500°C for 1 hour to remove the resin, and the mass of the sample before and after the treatment is weighed to calculate the mass of the aggregate of the shielding layer and the metal strip. Then, the volume ratio of the aggregate of the metal strip, the resin, and other additives can be calculated using the specific gravity of each component.

[0117] Mass ratio W(metal) = 100 × mass of the metal strip assembly / (mass of the metal strip assembly + mass of the resin + other additives)

[0118] [Occlusion layer: randomly scattered in the plane direction]

[0119] Figure 3 2 is a plan view showing an example of a shielding layer precursor 20. Figure 3As shown, the metal strips are dispersed in the in-plane direction of the shielding layer precursor 20. Here, the metal strips "dispersed in the in-plane direction" means that the metal strips are dispersed in a state of random directions in the plane of the shielding layer with the length direction of the metal strips facing the in-plane direction of the shielding layer in a state where the thickness direction of the metal strips is approximately the same as the thickness direction of the shielding layer. In the area where the press forming is performed without causing the shielding layer precursor 20 to flow, the shape of the metal strips is roughly maintained before and after forming. Therefore, the metal strips contained in the non-flowing area of ​​the shielding layer precursor are also preferably dispersed in the in-plane direction, and more preferably randomly dispersed. Random dispersion refers to a state in which the metal strips are not oriented in a specific direction such as one direction in the in-plane direction of the shielding layer precursor or the shielding layer, but are oriented in a disordered manner, and are arranged in the plane without showing a specific directionality as a whole. It should be noted that when preparing an aggregate of metal strips, even if a part of the metal strips is in a state of being sideways (a state in which the thickness direction of the metal strips is facing the in-plane direction of the shielding layer) (for example Figure 4 901), if the shielding layer precursor is press-formed, the metal strips are dispersed in the in-plane direction in the shielding layer after formation.

[0120] [Shielding layer: shielding of electric or magnetic fields]

[0121] 1. Preferably, the shielding layer shields at least one of the electric field or the magnetic field, and the shielding property of the electric field or the magnetic field is 10 decibels or more in at least a part of the region above 0 MHz and below 3000 MHz. The shielding property of the electric field or the magnetic field is more preferably 20 decibels or more, and further preferably 30 decibels or more. Here, the shielding property can be expressed as 10 times (decibels) the common logarithm of the ratio of the power of the electromagnetic wave before passing through the shielding layer to the power of the electromagnetic wave after passing through the shielding layer.

[0122] As a preferred range for each shielding area, in at least 50% of the area greater than 0 MHz and below 3000 MHz, the shielding property of the electric field or magnetic field is preferably 10 decibels or more. The shielding property of the electric field or magnetic field is more preferably 20 decibels or more, and further preferably 30 decibels or more. The so-called "in at least 50% of the area greater than 0 MHz and below 3000 MHz" means that the shielding area may exist continuously or discontinuously in the area greater than 0 MHz and below 3000 MHz.

[0123] As a preferred range for each shielding region, the shielding property of the electric field or magnetic field is preferably 10 decibels or more in the entire region above 0 MHz and below 3000 MHz, more preferably 20 decibels or more, and even more preferably 30 decibels or more.

[0124] 2. Next, more preferable shielding properties will be described.

[0125] The shielding layer shields at least one of the electric field or the magnetic field, and the shielding property of the electric field or the magnetic field is preferably 10 decibels or more in at least a portion of the region above 0 MHz and below 100 MHz, more preferably 20 decibels or more, and even more preferably 30 decibels or more.

[0126] As a preferred range for each shielding area, in at least 50% of the area greater than 0 MHz and below 100 MHz, the shielding property of the electric field or magnetic field is preferably 10 decibels or more. The shielding property of the electric field or magnetic field is more preferably 20 decibels or more, and further preferably 30 decibels or more. The so-called "in at least 50% of the area greater than 0 MHz and 100 MHz" means that the shielding area may exist continuously or discontinuously in the area greater than 0 MHz and 100 MHz.

[0127] As a preferred range for each shielding region, the shielding property of the electric field or magnetic field is preferably 10 decibels or more in the entire region above 0 MHz and below 100 MHz, more preferably 20 decibels or more, and even more preferably 30 decibels or more.

[0128] use Figure 5A to Figure 5F The graph depicted in the figure illustrates the shielding performance. Figure 5A This is a graph showing the electric field shielding performance of a polypropylene resin layer having a thickness of 150 μm. Figure 5B This is a graph showing the electric field shielding performance when the mass ratio W of the aluminum thin film is 25% in a 150 μm-thick shielding layer including the aluminum thin film and the polypropylene resin. Figure 5C This is a graph showing the electric field shielding performance when the mass ratio W of the aluminum thin film is 45% in a 150 μm-thick shielding layer including the aluminum thin film and the polypropylene resin. Figure 5D This is a graph showing the electric field shielding performance when the mass ratio W of the aluminum thin film is 65% in a 150 μm-thick shielding layer including the aluminum thin film and the polypropylene resin. Figure 5E This is a graph showing the electric field shielding performance when the mass ratio W of the aluminum thin film is 75% in a 150 μm-thick shielding layer including the aluminum thin film and the polypropylene resin. Fig. 5F This is a graph showing the electric field shielding performance of an aluminum thin film having a thickness of 150 μm. Figure 5A to Figure 5F The horizontal axis is frequency (Hz) and the vertical axis is decibel (dB). Figure 5A 0.1MHz(10 5 :1.00E+05) or more and 100MHz(10 8 :1.00E+08) or less ( Figure 8 In the arrow area of ​​801 of A), the electric field is not shielded at all. Figure 5BIn the region between 0.1MHz and 100MHz, the electric field shielding performance is about 20dB. Figure 5C In the region above 0.1MHz and below 100MHz, the electrolytic shielding performance is about 33dB. Figure 5D In the region above 0.1MHz and below 100MHz, the electrolytic shielding performance is about 35 to 50dB. Figure 5E In the region above 0.1MHz and below 100MHz, the electrolytic shielding performance is about 35 to 76dB. Fig. 5F In the region of 0.1 MHz to 100 MHz, the electrolytic shielding performance is about 35 to 122 dB.

[0129] [Thickness of shielding layer]

[0130] The thickness tx of the shielding layer in the present invention is not particularly limited, as long as it is greater than the thickness ty of the metal tape. Ideally, it is sufficient as long as the shielding layer has the same thickness tx as the thickness ty of a piece of metal tape. Even if the thickness of the shielding layer is increased, the shielding property will not be greatly improved. This is because if the thickness ty of the metal tape is greater than 10 μm, the thickness of the shielding layer is not too dependent on the improvement of the shielding property.

[0131] However, from the viewpoint of preventing gaps, it is preferred to reduce the thickness of the metal strip and increase the density of the assembly (increase the number of metal strips per unit area). Therefore, when the thickness of the shielding layer is set to tx and the thickness of the metal strip is set to ty, it is preferred to have a portion satisfying 2≤tx / ty, more preferably a portion satisfying 3≤tx / ty, and even more preferably a portion satisfying 5≤tx / ty. It should be noted that in the case where the shielding layer is uneven in the integrally formed body, such as when the thickness of the shielding layer is different between the vertical surface and the top surface, any one of them can be within the above range.

[0132] [Shielding layer: reinforced fiber]

[0133] Reinforcing fibers may also be added to the shielding layer. This is to prevent the aggregate of the metal strips from being scattered and hanging when the shielding layer is subjected to a combustion test. In addition, if reinforcing fibers are added to the shielding layer, the ductility is also improved. As the reinforcing fibers mixed into the shielding layer, aramid fibers, glass fibers, or carbon fibers are preferred.

[0134] [Shielding layer: Method for producing shielding layer precursor]

[0135] The one-piece molded body of the present invention is preferably manufactured by laminating a fiber-reinforced resin containing reinforcing fibers and a first matrix resin with a shielding layer precursor and performing press molding using a molding upper mold and a molding lower mold (sometimes collectively referred to as a molding upper and lower mold). That is, the shielding layer is obtained by molding the shielding layer precursor. The manufacturing method of the shielding layer precursor is not particularly limited, and it can be manufactured as follows.

[0136] 1. Preparation of metal strip assembly

[0137] 1.1 Cutting

[0138] The aggregate of metal strips can be produced by slitting a wide metal film and then cutting it.

[0139] 1.1.1 Pressing and slitting to the roller ( Figure 6 )

[0140] Figure 6 Indicates that the metal film is Figure 6 Schematic diagram of a metal strip 501 which is pressed by a lower support roller (rubber roller 503) and cut by a knife 502 to produce a thin bundle. Figure 6 As shown, the metal film is pressed against a high-hardness rubber roller 503 that has been subjected to heat treatment such as quenching to perform slitting. In this case, it is necessary to adjust so that the rubber roller 503 is not damaged and the metal film is not sandwiched.

[0141] 1.1.2 Cutting with shear knife ( Figure 7 to Figure 9 )

[0142] Figure 7 to Figure 9 A schematic diagram of cutting the metal film 603 by a shear knife is shown in FIG. Figure 7 603 is a side view showing a state where a metal film 603 passes between an upper rotating blade 601 and a lower rotating blade 602. Figure 8 yes Figure 7 The cross-sectional view along the line VIII-VIII, Fig. 9 yes Figure 8 An enlarged view of section IX. Figure 7 to Figure 9 As shown, the upper rotary blade 601 has an acute blade tip 604 with a clearance angle, and the metal film 603 is pressed against the side of the front end 605 of the lower rotary blade 602 to be cut by the blade assembly. In this case, high-precision gap management is required over time.

[0143] 1.1.3 Combination knife method ( Figure 10 to Figure 12 )

[0144] Figure 10 to Figure 12 Schematic diagram showing the opening of reinforcing fiber bundles by a combination of knives. Fig.10 701 is a side view showing a state where the metal film 673 passes between the upper rotating blade 701 and the lower rotating blade 702. Fig.11yes Fig.10 The XI-XI line cross-sectional view, Fig.12 yes Fig.11 An enlarged view of Section XII. Figure 10 to Figure 12 As shown, the upper knife 704 of the upper rotary knife 701 as a rotary circular knife and the lower knife 705 of the lower rotary knife are combined in a structure that can form a small gap and overlap at the top, and the reinforcing fiber bundle is sandwiched in the overlapping part, and the shear force of the overlapping part of the upper knife and the lower knife is used to loosen. As with the shear knife method, high-precision gap management is required over time.

[0145] 1.2 Cutting of metal strip after slitting

[0146] The slit metal strips are cut to length using a rotary cutter, for example, and then spread and fixed on a pre-made resin on an air-permeable support that is provided directly below the rotary cutter and has a suction mechanism at the bottom and that continuously moves in one direction, thereby obtaining a collection of metal strips. The resin is preferably in the form of a film or a nonwoven fabric.

[0147] 2. Second base resin

[0148] The metal film in the shielding layer is fixed by the second matrix resin. The second matrix resin contained in the shielding layer can be a thermosetting resin or a thermoplastic resin. The first matrix resin and the second matrix resin are preferably the same resin. Hereinafter, the first matrix resin is also referred to as resin A, and the second matrix resin is also referred to as resin B.

[0149] 2.1. Thermoplastic resin

[0150] When the resin used as the first matrix resin or the second matrix resin is a thermoplastic resin, its type is not particularly limited, and a resin having a desired softening point or melting point can be appropriately selected and used. As the above-mentioned thermoplastic resin, a thermoplastic resin having a softening point in the range of 180° C. to 350° C. is generally used, but it is not limited thereto.

[0151] Examples of thermoplastic resins include polyolefin resins, polystyrene resins, polyamide resins, polyester resins, polyacetal resins (polyoxymethylene resins), polycarbonate resins, (meth)acrylic resins, polyarylate resins, polyphenylene ether resins, polyimide resins, polyether nitrile resins, phenolic resins, polyphenylene sulfide resins, polysulfone resins, polyketone resins, polyether ketone resins, thermoplastic polyurethane resins, fluorine-based resins, and thermoplastic polybenzimidazole resins.

[0152] The thermoplastic resin used in the integrally formed body of the present invention may be only one type or may be two or more types. As a method of using two or more thermoplastic resins in combination, for example, a method of using thermoplastic resins having different softening points or melting points in combination, a method of using thermoplastic resins having different average molecular weights in combination, etc. can be cited, but it is not limited thereto.

[0153] When a thermoplastic resin is used, a polyolefin resin is more preferably used, and a polypropylene resin is further preferably used.

[0154] 2.2. Thermosetting resin

[0155] The first matrix resin may also be a thermosetting resin. When a thermosetting resin is used, unsaturated polyester resin, vinyl ester resin, epoxy resin, or phenol resin is preferred. As the resin, one type may be used alone, or two or more types may be used in combination.

[0156] In addition, fiber-reinforced resins can also use sheet molding compounds (sometimes called SMC) containing reinforcing fibers. Sheet molding compounds can be easily molded even into complex shapes due to their high moldability. Sheet molding compounds have higher fluidity and shapeability than continuous fibers, making it easy to make ribs and protrusions.

[0157] 3. Welding of metal strip assemblies

[0158] The metal tape assembly is further sandwiched with resin from above to form a three-layer laminate of “resin / metal tape assembly / resin.” When the resin is a thermoplastic resin, the shielding layer precursor is completed by melting the resin and fusing it to the metal tape.

[0159] At this time, the resin may or may not enter between the aggregates of the metal strips. In order to increase the welding strength between the metal strips, an adhesive may be attached to the metal strips in advance.

[0160] In the embodiment, the metal strips are sandwiched and welded using polypropylene resin. A single shielding layer precursor 20 may be used to form an integral part with the fiber-reinforced resin 10, or two or more shielding layer precursors 20 may be stacked or not stacked and used to form an integral part with the fiber-reinforced resin 10.

[0161] [Shielding layer: ductility]

[0162] Ductility refers to the degree to which a material can be deformed by an external force and continue to stretch without being destroyed. Generally speaking, it means that when an external force is applied to a material, it deforms, and the deformation continues and the material is stretched. For example, metals have high ductility and can be stretched thinly. This property is used to process metal products or to manufacture wires, etc. On the other hand, brittle materials such as glass and ceramics have low ductility and tend to be easily destroyed if an external force is applied. In general, metals have poorer shapeability than resins.

[0163] In the integrally molded body of the present invention, the relationship between the ductility E1 of the fiber-reinforced resin and the ductility E2 of the laminate of the fiber-reinforced resin and the shielding layer precursor is preferably 0.9<E1 / E2<50, more preferably 1<E1 / E2<20, further preferably 1<E1 / E2<10, and further preferably 1<E1 / E2<7.

[0164] In the present invention, the fiber-reinforced resin is preferably in a plate-like shape, and the shielding layer precursor is made to flow in the in-plane direction of the fiber-reinforced resin to perform surface extension, thereby manufacturing a pressed molded body. In addition, in the present invention, the ductility of the fiber-reinforced resin is preferably greater than 1% and less than 300%, and more preferably greater than 20% and less than 150%.

[0165] The ductility of the laminate of the fiber-reinforced resin and the shielding layer precursor is preferably greater than 2% and less than 100%, and more preferably greater than 10% and less than 80%. If reinforcing fibers are mixed in the shielding layer precursor, the ductility is improved. In addition, preferably E1>E2. When the values ​​of E1 and E2 are close, it is easy to form an integral molded body. The method for measuring ductility is described later. In addition, ductility is sometimes also referred to as elongation, which is expressed as a percentage.

[0166] [Obscuration layer: comparison with continuous fiber web]

[0167] As a method for making the shielding layer follow the fiber-reinforced resin, there is also the following idea, for example: use continuous metal fibers that can shield electric fields or magnetic fields, make them into a mesh, and stack them with fiber-reinforced resin to make an integral molded body. By setting it in a mesh shape, the ductility of the shielding layer precursor can be made close to the ductility of the fiber-reinforced resin, and the moldability is improved. However, if the continuous metal fibers are formed into a mesh shape to prepare the shielding layer precursor, the mesh (space) of the mesh will expand during the molding process (also called gap expansion), and the shielding ability will decrease. The shielding layer of the present invention can reduce the impact of the decrease in the shielding ability of the shielding layer before and after molding.

[0168] [Fiber-reinforced resin layer: Reinforced fiber]

[0169] In the present specification, the reinforcing fiber is preferably at least one selected from carbon fiber, aramid fiber, and glass fiber. More preferably, the reinforcing fiber is carbon fiber or glass fiber.

[0170] [Fiber-reinforced resin layer: Reinforced fiber (carbon fiber)]

[0171] 1. All carbon fiber

[0172] When using carbon fiber, generally known are polyacrylonitrile (PAN) carbon fiber, petroleum / coal tar carbon fiber, rayon carbon fiber, cellulose carbon fiber, lignin carbon fiber, phenolic carbon fiber, etc. In the present invention, these carbon fibers can be used appropriately. Among them, in the present invention, polyacrylonitrile (PAN) carbon fiber is preferably used from the aspect of excellent tensile strength. As PAN carbon fiber, for example, carbon fiber "Tenax" (registered trademark) STS40-24KS (average fiber diameter 7 μm) manufactured by Teijin Co., Ltd. can be used.

[0173] 2. Carbon fiber sizing agent

[0174] The carbon fibers used in the present invention may have a sizing agent attached to their surfaces. When using carbon fibers to which a sizing agent is attached, the type of the sizing agent may be appropriately selected according to the type of carbon fibers and the type of resin, and is not particularly limited.

[0175] [Fiber-reinforced resin layer: Reinforced fiber (glass fiber)]

[0176] The case where the reinforcing fiber used in the present invention is glass fiber will be described.

[0177] 1. Glass fiber overall

[0178] The glass fiber used in the present invention may be any glass fiber as long as it is generally called glass fiber. The glass composition of A glass, C glass, E glass, etc. is not particularly limited, and may contain components such as TiO2, SO3, P2O5, etc. as appropriate. As the glass fiber, for example, glass fiber E-glass RS240QR-483 (count: 2400g / 1000m) manufactured by Nitto Bosho Co., Ltd. may be used.

[0179] 2. Sizing agent for glass fiber

[0180] The glass fiber used in the present invention may have a sizing agent attached to the surface. When using glass fibers with a sizing agent attached, the type of the sizing agent can be appropriately selected according to the type of glass fiber and the type of resin, and is not particularly limited. Glass fibers are preferably pretreated with conventionally known coupling agents such as organosilane compounds, organotitanium compounds, organoborane compounds, and epoxy compounds.

[0181] [Fiber-reinforced resin layer: reinforcing fibers dispersed in the in-plane direction]

[0182] The reinforcing fibers of the present invention are discontinuous fibers, and are preferably dispersed in the in-plane direction of the fiber-reinforced resin layer. In addition, in order to disperse in the in-plane direction in the fiber-reinforced resin layer, it is preferred to disperse the reinforcing fibers contained in the fiber-reinforced resin in advance in the in-plane direction. The reinforcing fibers dispersed in the in-plane direction refer to being dispersed in a manner such that the fiber axis of the reinforcing fibers faces the in-plane direction. The angle between the fiber axis of the reinforcing fibers and the in-plane direction is preferably 45° or less.

[0183] 1. In-plane direction

[0184] The in-plane direction refers to an indefinite direction of a parallel plane perpendicular to the plate thickness direction of the fiber-reinforced resin or the fiber-reinforced resin layer. The fiber-reinforced resin is preferably a plate-shaped material.

[0185] 2. Random dispersion in two dimensions

[0186] The reinforcing fibers are preferably randomly dispersed in the in-plane direction in two dimensions. In the region where the fiber-reinforced resin is not made to flow but is press-molded, the shape of the reinforcing fibers is substantially maintained before and after molding. Therefore, the reinforcing fibers contained in the non-flowing region of the fiber-reinforced resin layer formed by molding the fiber-reinforced resin are also preferably randomly dispersed in the in-plane direction in two dimensions.

[0187] Here, two-dimensional random dispersion means that the reinforcing fibers are not oriented in a specific direction such as one direction in the in-plane direction of the fiber-reinforced resin or the fiber-reinforced resin layer, but are randomly oriented, and are arranged in the sheet surface in a manner that does not show a specific directionality as a whole. The fiber-reinforced resin or the fiber-reinforced resin layer obtained using the two-dimensionally randomly dispersed discontinuous fibers does not have anisotropy in the plane, but is substantially isotropic.

[0188] It should be noted that the degree of two-dimensional random orientation is evaluated by finding the ratio of the tensile modulus in two directions orthogonal to each other. For any direction of the fiber-reinforced resin or the fiber-reinforced resin layer and the direction orthogonal thereto, if the ratio (Eδ) obtained by dividing the larger of the values ​​of the tensile modulus measured by the smaller is 5 or less, more preferably 2 or less, and further preferably 1.5 or less, it can be evaluated that the reinforcing fibers are two-dimensionally randomly dispersed.

[0189] When the resin contained in the fiber-reinforced resin layer is a thermoplastic resin, and the fiber-reinforced resin layer is a three-dimensionally shaped resin layer including a curved surface, as a method for evaluating the two-dimensional random dispersion in the in-plane direction, the fiber-reinforced resin layer can be cured after being heated to a softening temperature or higher to restore the flat plate shape. Then, a test piece is cut out to obtain the tensile elastic modulus, thereby confirming the random dispersion state in the two-dimensional direction.

[0190] [Fiber-reinforced resin layer: fiber length of reinforcing fibers]

[0191] The reinforcing fiber is preferably a discontinuous fiber. When using discontinuous fibers, compared with fiber-reinforced plastics using only continuous fibers, the shaping property is improved, and it is easy to make a complex fiber-reinforced resin layer. Since the weight-average fiber length of the reinforcing fiber does not change before and after molding, if the weight-average fiber length of the reinforcing fiber of the fiber-reinforced resin layer is investigated, the weight-average fiber length Lw of the reinforcing fiber contained in the fiber-reinforced resin can be known.

[0192] The weight average fiber length Lw of the reinforcing fiber is preferably more than 1mm, more preferably more than 3mm. The weight average fiber length Lw of the reinforcing fiber is more preferably more than 3mm and less than 100mm, more preferably more than 3mm and less than 80mm, and more preferably more than 5mm and less than 60mm. If the weight average fiber length Lw of the reinforcing fiber is less than 100mm, when the fiber-reinforced resin is press-formed and manufactured, the fluidity of the fiber-reinforced resin is not easy to reduce, and it is easy to make it in a desired shape. In addition, when the weight average fiber length Lw is more than 1mm, the mechanical strength of the obtained fiber-reinforced resin part is not easy to reduce, so it is preferred.

[0193] The weight average fiber length Lw and the number average fiber length Ln of the reinforcing fibers are determined by the equations (1) and (2) described below.

[0194] It should be noted that in the fiber-reinforced resin layer produced by injection molding, the weight average fiber length of the reinforcing fibers is about 0.1 to 0.3 mm. Therefore, when the weight average fiber length of the reinforcing fibers is 1 mm or more and 100 mm or less, it is preferred to produce the fiber-reinforced resin layer by press molding.

[0195] In the present invention, discontinuous reinforcing fibers having different fiber lengths may be used in combination. In other words, the discontinuous reinforcing fibers used in the present invention may have a single peak or a plurality of peaks in the distribution of the weight-average fiber length.

[0196] [Fiber-reinforced resin layer: number average fiber length Ln and weight average fiber length Lw of reinforcing fibers]

[0197] Generally, when the fiber length of each reinforcing fiber is defined as Li, the number average fiber length Ln and the weight average fiber length Lw are obtained by the following equations (1) and (2). The units of the number average fiber length Ln and the weight average fiber length Lw are mm.

[0198] [Number 1]

[0199]

[0200] Here, "I" represents the number of measured reinforcing fibers.

[0201] When the fiber length is constant, the number average fiber length and the weight average fiber length are the same value. The reinforcing fibers from the fiber-reinforced resin layer can be extracted by, for example, performing a heating treatment at about 500° C. for 1 hour to remove the resin in a furnace.

[0202] The average fiber length can be determined based on the formula (1) or (2) by measuring the fiber lengths of 100 fibers randomly extracted from the fiber-reinforced resin layer to 1 mm using a vernier caliper or the like, for example.

[0203] In the case of containing short fibers that cannot be measured with a vernier caliper, after removing the resin, the obtained reinforced fibers are put into water containing a surfactant and stirred thoroughly by ultrasonic vibration. The stirred dispersion can be randomly collected with a measuring spoon to obtain a sample for evaluation, and the length of 3000 fibers can be measured using an image analyzer Luzex AP manufactured by Nireco. The measured value of the fiber length can be used to calculate the number average fiber length Ln and the weight average fiber length Lw in the same manner as the above-mentioned formulas (1) and (2).

[0204] [Fiber-reinforced resin layer: fiber volume ratio of reinforcing fibers]

[0205] The fiber volume ratio Vf of the reinforcing fiber is not particularly limited, and is preferably 20% to 70%, more preferably 25% to 60%, and further preferably 30% to 55%. It should be noted that the fiber volume ratio (Vf unit: volume %) refers to the ratio of the volume of the reinforcing fiber to the overall volume including not only the reinforcing fiber and the resin but also other additives.

[0206] The analysis of the reinforcing fiber volume ratio is not limited, and can be measured as follows.

[0207] Samples were cut out from the fiber-reinforced resin layer, and the resin was burned off in a furnace at 500°C for 1 hour. The mass of the sample before and after the treatment was weighed to calculate the mass of the reinforcing fiber, resin, and other additives. Next, the volume ratio of the reinforcing fiber to the resin was calculated using the specific gravity of each component.

[0208] Vf = 100 × reinforcement fiber volume / (reinforcement fiber volume + resin volume + other additives)

[0209] [Fiber-reinforced resin layer: first matrix resin]

[0210] The first matrix resin contained in the fiber-reinforced resin layer may be a thermosetting resin or a thermoplastic resin.

[0211] 1. Thermoplastic resin

[0212] When the resin used is a thermoplastic resin, its type is not particularly limited, and a resin having a desired softening point or melting point can be appropriately selected and used. As the thermoplastic resin, a thermoplastic resin having a softening point in the range of 180° C. to 350° C. is generally used, but is not limited thereto.

[0213] Examples of thermoplastic resins include polyolefin resins, polystyrene resins, polyamide resins, polyester resins, polyacetal resins (polyoxymethylene resins), polycarbonate resins, (meth)acrylic resins, polyarylate resins, polyphenylene ether resins, polyimide resins, polyether nitrile resins, phenoxy resins, polyphenylene sulfide resins, polysulfone resins, polyketone resins, polyether ketone resins, thermoplastic polyurethane resins, fluorine-based resins, and thermoplastic polybenzimidazole resins.

[0214] The thermoplastic resin used in the fiber-reinforced resin layer of the present invention may be only one type or two or more types. As a method of using two or more thermoplastic resins in combination, for example, a method of using thermoplastic resins having different softening points or melting points in combination, a method of using thermoplastic resins having different average molecular weights in combination, etc. can be cited, but it is not limited thereto. When using a thermoplastic resin, it is more preferred to use a polyolefin resin, and it is further preferred to use a polypropylene resin.

[0215] 2. Thermosetting resin

[0216] The first matrix resin may also be a thermosetting resin. When a thermosetting resin is used, unsaturated polyester resin, vinyl ester resin, epoxy resin, or phenol resin is preferred. As the resin, one type may be used alone or two or more types may be used in combination.

[0217] In addition, fiber-reinforced resins can also use sheet molding compounds (sometimes called SMC) containing reinforcing fibers. Sheet molding compounds can be easily molded even into complex shapes due to their high moldability. Sheet molding compounds have higher fluidity and shapeability than continuous fibers, making it easy to make ribs and protrusions.

[0218] [Fiber reinforced resin layer: other agents]

[0219] The first matrix resin used in the fiber-reinforced resin may contain various fibrous or non-fibrous fillers of organic or inorganic fibers, flame retardants, UV-resistant agents, stabilizers, mold release agents, pigments, softeners, plasticizers, surfactants and other additives within the scope of not impairing the purpose of the present invention. In the case of using a thermosetting resin, it may contain a thickener, a curing agent, a polymerization initiator, an inhibitor, etc. As additives, one may be used alone, or two or more may be used in combination.

[0220] [Thermoplastic resin and non-flow molding]

[0221] The first matrix resin and the second matrix resin of the present invention are preferably thermoplastic resins of the same type. In addition, from the viewpoint that the shielding layer precursor needs to be molded following the fiber-reinforced resin, it is preferred that the fiber-reinforced resin is not flow-molded during molding. More preferably, the first matrix resin and the second matrix resin are thermoplastic resins of the same type, and the filling rate of the area of ​​the fiber-reinforced resin relative to the total area of ​​the molding die cavity is 80% or more. The area filling rate of the shielding layer precursor relative to the total area of ​​the molding die cavity is more preferably 80% or more.

[0222] [Manufacturing method: one-piece molding]

[0223] The integrally molded body of the present invention is an integrally molded body of a fiber-reinforced resin layer including reinforcing fibers and a first matrix resin, and a shielding layer. The integrally molded body is formed by integrally molding a fiber-reinforced resin layer including reinforcing fibers and a first matrix resin and a shielding layer. Here, integrally molded means that they are continuously molded without seams, and are not molded by joining separate parts to each other. Such integral molding is performed by one-time molding to produce a molded body, preferably by press molding. Since it is produced by integral molding, the separate components can be processed as a single component, and the unit price of the component can be reduced. In addition, the number of assembly steps is reduced, and the costs related to inventory can also be reduced by reducing the number of components.

[0224] [Manufacturing method: press molding]

[0225] The integrally molded body of the present invention can be produced by laminating a fiber-reinforced resin containing reinforcing fibers and a first matrix resin and a shielding layer precursor, and performing press molding using upper and lower molding dies.

[0226] More specifically, when the first matrix resin and the second matrix resin are thermoplastic resins, the fiber-reinforced resin and the shielding layer precursor are heated, overlapped, and simultaneously pressed in a molding die to produce an integrally molded body.

[0227] 1. Fiber-reinforced resin and shielding layer precursor

[0228] The method of superimposing the fiber-reinforced resin and the shielding layer precursor is not particularly limited, but since the shielding layer precursor has high conformability to the fiber-reinforced resin, the two can be superimposed in the same size.

[0229] The volume ratio of the fiber-reinforced resin Vx to the shielding layer precursor Vy is not particularly limited, but Vx:Vy is preferably 99:1 to 60:40, and more preferably 98:2 to 66:34. Within this range, the shielding layer will not be too thick and moldability will be good.

[0230] 2. Hot pressing and cold pressing

[0231] As the molding method in the present invention, press molding (sometimes also referred to as compression molding) is utilized, and molding methods such as hot press molding and cold press molding can be utilized.

[0232] 2.1 Cold Pressing

[0233] When a thermoplastic resin is used as the resin, press molding using cold press is preferred. In the cold press molding method, for example, a fiber-reinforced resin and a shielding layer precursor heated to a first predetermined temperature are placed in a molding die set to a second predetermined temperature, followed by pressurization and cooling.

[0234] Specifically, when the thermoplastic resin constituting the fiber-reinforced resin and the shielding layer precursor is crystalline, the first specified temperature is above the melting point, and the second specified temperature is below the melting point. When the thermoplastic resin is amorphous, the first specified temperature is above the glass transition temperature, and the second specified temperature is below the glass transition temperature. That is, the cold pressing method includes at least the following steps A-1) to A-2).

[0235] Step A-1): A step of heating the thermoplastic resin to a temperature not lower than the melting point and not higher than the decomposition temperature when the thermoplastic resin is crystalline, or heating the thermoplastic resin to a temperature not lower than the glass transition temperature and not higher than the decomposition temperature when the thermoplastic resin is amorphous.

[0236] Step A-2): The fiber-reinforced resin and the shielding layer precursor heated in the above step A-1) are placed in a molding die and pressurized, wherein the molding die is adjusted to a temperature lower than the melting point when the thermoplastic resin is crystalline, and the molding die is adjusted to a temperature lower than the glass transition temperature when the thermoplastic resin is amorphous. By performing these steps, the molding of the fiber-reinforced resin and the shielding layer precursor can be completed (a press-molded body can be manufactured).

[0237] The above-mentioned steps need to be performed in the above-mentioned order, but other steps may be included between the steps. For example, the other steps include a shaping step of pre-shaping the shape of the cavity of the molding die using a shaping die different from the molding die used in step A-2) before step A-2).

[0238] The shape of at least one of the fiber-reinforced resin and the shielding layer precursor may be a shape developed by inverse molding analysis using a computer from the three-dimensional shape of the manufactured press-molded body.

[0239] 2.2 Hot Pressing

[0240] In the hot press molding method, for example, a fiber-reinforced resin is put into a molding die, and the molding die is pressurized while the temperature is raised to a first predetermined temperature, and then the molding die is cooled to a second predetermined temperature. Specifically, when the thermoplastic resin constituting the fiber-reinforced resin and the shielding layer precursor is crystalline, the first predetermined temperature is above the melting point, and the second predetermined temperature is below the melting point. When the thermoplastic resin constituting the fiber-reinforced resin and the shielding layer precursor is amorphous, the first predetermined temperature is above the glass transition temperature, and the second predetermined temperature is below the glass transition temperature.

[0241] The hot press molding preferably includes at least the following steps B-1) to B-4).

[0242] B-1): A step of placing a fiber-reinforced resin and a shielding layer precursor in a molding die (lower die).

[0243] B-2): When the thermoplastic resin is crystalline, the molding die is heated to a temperature not less than the melting point and not more than the thermal decomposition temperature of the thermoplastic resin; when the thermoplastic resin is amorphous, the molding die is heated to a temperature not less than the glass transition temperature and not more than the thermal decomposition temperature of the thermoplastic resin, and pressurized (first pressing step).

[0244] B-3): A step of applying pressure in one or more stages and in the final stage so as to be 1.2 to 100 times the pressure in the first pressing step (second pressing step).

[0245] B-4): A step of adjusting the temperature of the molding die to be lower than the melting point when the thermoplastic resin is crystalline, and adjusting the temperature of the molding die to be lower than the glass transition temperature when the thermoplastic resin is amorphous.

[0246] By performing these steps, an integrally molded body can be produced.

[0247] 3. Common points between cold press molding and hot press molding

[0248] Process A-2) and B-3) are processes for applying pressure to the fiber-reinforced resin and the shielding layer precursor to obtain a molded body of the desired shape. The molding pressure at this time is not particularly limited, but it is preferably as low as possible within the range that can obtain the desired structural shape. Specifically, relative to the projected area of ​​the molding mold cavity, it is preferably less than 30MPa, more preferably below 20MPa, and further preferably below 10MPa. When the molding pressure is lower than 30MPa, the equipment investment and maintenance costs of the press are not required, so it is preferred. In addition, of course, various processes can be placed between the above-mentioned processes during compression molding. For example, vacuum compression molding can be used while compression molding is performed under vacuum.

[0249] 4. Configuration of fiber-reinforced resin and shielding layer precursor (stacking order)

[0250] The stacking order of the fiber-reinforced resin and the shielding layer precursor is not particularly limited. In the case of cold press molding, it is preferably arranged in a molding die in a manner that the appearance surface contacts the molding upper mold for compression molding. For example, in the case where the shielding layer is the appearance surface, it is preferably stacked in sequence on the molding die in a manner that the fiber-reinforced resin contacts the molding lower mold for cold press molding. In the case of cold press molding, if the material forming the appearance surface (such as the shielding layer precursor) is not brought into contact with the molding lower mold, the thermoplastic resin of the material forming the appearance surface is not cooled until just before compression (until the material forming the appearance surface contacts the molding upper mold), and therefore the mirror surface of the molding mold is easily transferred.

[0251] [Manufacturing method: RTM molding]

[0252] The one-piece molded body of the present invention can also be manufactured using RTM molding (Resin Transfer Molding). For example, a fabric substrate using reinforcing fibers such as glass fibers and carbon fibers is first placed in a molding mold in a dry fabric state without a first matrix resin. At this time, a shielding layer precursor is placed on the fabric substrate in a dry fabric state, and the molding mold is closed. Then, a thermosetting second matrix resin such as epoxy resin with good fluidity (easy to penetrate into the fiber) is filled. The mold can be heated at the location where the resin is distributed to promote the curing of the epoxy resin. Even this method can produce the one-piece molded body of the present invention in which the fiber-reinforced resin layer containing reinforcing fibers and the first matrix resin is integrally molded with the shielding layer.

[0253] In addition, it is preferable to use a first matrix resin that cures at a temperature lower than the softening temperature of the second matrix resin. This is because by setting the mold temperature of the molding mold used for RTM molding to be lower than the softening temperature of the second matrix resin, the shielding layer is also cured when the molding of the fiber-reinforced resin layer is completed.

[0254] Assuming that a first matrix resin that cures at a temperature higher than the softening temperature of the second matrix resin is used, by setting a process in which the mold temperature of the molding mold used for RTM molding is set to be higher than the softening temperature of the second matrix resin and the first matrix resin is cured, and then the mold temperature is lowered to below the softening temperature of the second matrix resin, it is possible to demold the fiber-reinforced resin layer and the shielding layer in a cured state.

[0255] In recent years, the development of fast-curing resins has continued to advance, and RTM molding has contributed to the mass production of large composite products.

[0256] [Shape of the integrally molded body]

[0257] The integrally formed body 1A has a plane portion and a vertical portion. Specifically, it is preferred to have at least one plane portion, and the plane portion has at least one thickness (plate thickness). The integrally formed body may be a three-dimensional shape including a T-shaped, L-shaped, U-shaped, or hat-shaped cross-sectional shape, and may also have a concave-convex shape (e.g., ribs, bosses, etc.).

[0258] Fig.13 1A is a cross-sectional view showing an example of an integrally molded body 1A according to an embodiment of the present invention. Figure 1 The laminated body 1 shown is formed to obtain. Fig.13 As shown, the cross-sectional shape of the integrally formed body 1A manufactured by the present invention is preferably a shape including a hat-shaped portion having a top surface portion 50 and a vertical surface portion 60. The top surface portion 50 is an example of a flat surface portion. For example, even a side door, a rear door, or a roof for an automobile may have the vertical surface portion and the top surface portion of the present invention.

[0259] The thickness ta of the vertical portion of the integral molded body 1A and the thickness tb of the top portion are preferably ta≤tb. It is more preferably ta×0.8<tb, and further preferably ta×0.6<tb. For example, when a plate-shaped shielding layer precursor 20 and a fiber-reinforced resin 10 are used, the thickness of the laminate 1 of the shielding layer precursor 20 and the fiber-reinforced resin 10 is a uniform wall thickness. When a hat-shaped integral molded body is made using it, the vertical portion tends to be stretched by the molding die and become thinner than the top portion.

[0260] On the other hand, in the one-piece molded body 1A of the present invention, when the thickness ta of the vertical portion 60 and the thickness tb of the top portion 50 are made the same thickness, it is preferred that the thickness of the shielding layer 20A in the vertical portion 60 is txa, the thickness of the fiber reinforced resin layer 10A is ta-txa, the thickness of the shielding layer 20A in the top portion 50 is txb, and the thickness of the fiber reinforced resin layer 10A is tb-txb, then txa≤txb and ta-txa≥tb-txb are satisfied.

[0261] That is, since the fiber-reinforced resin 10 has greater ductility than the shielding layer precursor 20 , the wall thickness of the vertical portion 60 can be easily increased during molding.

[0262] [One-piece molding: battery tray and battery cover]

[0263] The integrally formed body is preferably a vehicle structure. In addition, the vehicle structure is preferably a component of a battery box, and the component of the battery box is preferably arranged at the lower part of the vehicle body.

[0264] Fig.14 1 is an exploded perspective view of a battery box 101 using an integrally formed body of the present embodiment. The battery box 101 includes a battery cover 102, batteries 103, a temperature control system (cooling mechanism) 104, a battery tray 105, a reinforcing frame 106, and an energy absorbing member 107. The integrally formed body of the present embodiment can be used for the battery cover 102 and the battery tray 105. The batteries 103 are stored in the battery box 101 including the battery tray 105 and the battery cover 102.

[0265] [Battery tray: whole]

[0266] The following describes a case where a battery tray is used as a vehicle structure. The battery tray 105 is a battery tray for driving a vehicle for mounting a battery 103 for driving a vehicle.

[0267] Fig.15 is a three-dimensional diagram of the battery tray 105, Fig.16 yes Fig.15 The XVI-XVI sectional view. Fig.15 and Fig.16 As shown, the battery tray 105 includes a first bottom portion 303 and a peripheral wall 203 erected on the outer periphery of the first bottom portion 303. In addition, the battery tray 105 includes a first inner wall 204 connected to the first bottom portion 303, a second inner wall 205 connected to the first bottom portion 303, and a second bottom portion 301 connected to both the first inner wall 204 and the second inner wall 205 and suspended from the first bottom portion.

[0268] The first bottom surface portion 303 , the peripheral wall 203 , the first inner wall 204 , the second inner wall 205 , and the second bottom surface portion 301 constitute a part of the vehicle structure.

[0269] [Battery tray and shield]

[0270] When the vehicle structure is a battery box 101, the battery box 101 has a shielding layer for shielding electric fields or magnetic fields in order to shield electromagnetic waves generated by the battery 103. The shielding layer can shield electromagnetic waves radiated from the battery 103 to prevent radiation and leakage to the outside, and can ensure sufficient electromagnetic wave shielding properties of the battery box, for example, it can suppress the adverse effects of electromagnetic waves on the vehicle control system and human body.

[0271] [Shielding layer: following the concave part]

[0272] For example Fig.15 , Fig.16 The battery box shown in FIG. has a complex shape, such as Fig.15 There are large concave portions like 313 of FIG. How to cover such concave portions with a shielding layer becomes a problem, but if the shielding layer precursor of the present invention is used, it is easy to make the shielding layer follow the shape of such concave portions.

[0273] Example

[0274] 2. Evaluation

[0275] 2.1 Shielding

[0276] A 150 mm x 150 mm test piece (flat test piece) was sampled from the integral molded body, and the radio wave shielding property was measured for electric field waves (frequency exceeding 0 MHz and 100 MHz) using a network analyzer (manufactured by Keysight Technologies, Inc.) and a KEC method measuring device (manufactured by JSE, Inc.). The larger the value, the better the radio wave shielding property.

[0277] Good: The shielding property of electrolysis is 40 dB or more in the entire region of the range exceeding 0 MHz and not exceeding 100 MHz.

[0278] Poor: The shielding property of electrolysis is 5 dB or less in the entire region of the range exceeding 0 MHz and not exceeding 100 MHz.

[0279] 2.2 Determination of ductility of laminate of shielding layer precursor and fiber-reinforced resin

[0280] 2.2.1 Determination of molding heating temperature

[0281] (1) A fiber-reinforced resin (or a laminate of a shielding layer precursor and a fiber-reinforced resin) cut into 200 mm×200 mm is prepared.

[0282] (2) Fig.17AAs shown, a half area of ​​100 mm x 200 mm, which is a fiber reinforced resin 1001 (or a laminate of a shielding layer precursor and a fiber reinforced resin), is placed on a metal mesh 1002, and the metal mesh 1002 is placed on a placement table 1003 composed of a metal block and heated by an IR oven (infrared heater). The elastic modulus of the fiber reinforced resin (or a laminate of a shielding layer precursor and a fiber reinforced resin) is reduced, and the temperature when the fiber reinforced resin (or a laminate of a shielding layer precursor and a fiber reinforced resin) is drooped 10 mm from the original height is measured by self-weight, and the temperature at this time is taken as the softening temperature. This temperature + 50°C is used as the subsequent molding heating temperature.

[0283] 2.2.2 Pressing

[0284] (1) A fiber-reinforced resin (or a laminate of a shielding layer precursor and a fiber-reinforced resin) heated to a softening temperature + 50°C as a molding heating temperature is placed in a molding die having a spherical surface of 150 mm in diameter when viewed from above. Fig. 17B ).

[0285] At this time, the diameter (φ150 mm) of the spherical surface before the start of press molding was defined as the flight path length La before molding. This was press molded under the following conditions.

[0286] Pressing down speed: 100mm / sec

[0287] Mold closing speed: 10mm / sec

[0288] Forming load: 80ton

[0289] Forming mold: open cavity

[0290] Molding mold temperature: 60℃

[0291] (2) Next, by changing the descending height of the molding upper mold, the flight path length Lb after the molding is changed (for example Fig. 17C The obtained samples were visually observed, and the maximum route length Lb of the sample without light leakage was taken as the maximum extension length.

[0292] (3) Ductility (%) was measured by the following formula.

[0293] Ductility (%) = (Lb-La) / La×100

[0294] (4) Ductility of the laminate of fiber-reinforced resin, shielding layer precursor, and fiber-reinforced resin

[0295] The ductility E1 of the fiber-reinforced resin and the ductility E2 of the laminate of the fiber-reinforced resin and the shielding layer precursor were calculated, and the value of E1 / E2 was calculated.

[0296] The thickness of the shielding layer precursor is regarded as the thickness tx of the shielding layer on the top surface after molding, and tx / ty is calculated.

[0297] [Example 1]

[0298] 1. Shielding layer precursor

[0299] As the thermoplastic resin of the first layer, a nonwoven fabric of a polypropylene resin (Novatech (registered trademark) PPBC03C manufactured by Nippon Polypro Co., Ltd.) was prepared.

[0300] Next, as a metal film, an aluminum foil (made by UACJ foil) with a width of 20 cm and a thickness of 0.012 mm was slit using a rotary slitting machine with a pitch of 3 mm, and then cut to a fixed length using a rotary cutter to produce a metal strip with a length of 10 mm, a width of 3 mm, and a thickness of 0.012 mm. The metal strip was then spread / fixed on a thermoplastic resin nonwoven fabric (first layer of thermoplastic resin) pre-fabricated on a breathable support body that was arranged directly below the rotary cutter and continuously moved in one direction, thereby obtaining an aggregate of metal strips.

[0301] Furthermore, a polypropylene resin (Novatech PBC03C manufactured by Nippon Polypro Co., Ltd.) was laid on the prepared metal belt assembly using a feeder, and a second layer of thermoplastic resin was provided to obtain a composite composition in which the first layer of thermoplastic resin / metal belt assembly / second layer of thermoplastic resin were sequentially laminated. The prepared composite composition was heated at 2.0 MPa for 5 minutes using a press device heated to 250°C, and cooled to obtain a shielding layer precursor with a thickness of 0.15 mm and a size of 600 mm×1000 mm.

[0302] 2. Fiber-reinforced resin

[0303] As the glass fiber, glass fiber E-glass RS240QR-483 manufactured by Nitto Bosho Co., Ltd. with a sizing agent attached was cut to a fiber length of 20 mm. As the thermoplastic resin, a particulate polypropylene resin (Novatech PP BC03C manufactured by Nippon Polypro Co., Ltd.) having an average particle size of about 710 μm was used.

[0304] Based on the method described in US Pat. No. 8,946,342, a composite composition of glass fibers in which glass fibers are randomly oriented in two dimensions and a polypropylene resin was prepared.

[0305] Specifically, a permeable support body that continuously moves in one direction having a suction mechanism is provided at the lower part, and while suction is performed by the suction mechanism, the glass fiber and polypropylene resin are blown from a conical tube arranged above the permeable support body to the upper part of the permeable support body by compressed air to produce a composite product of a mixture of glass fiber and polypropylene resin.

[0306] The obtained composite composition was heated at 2.0 MPa for 5 minutes in a press device heated to 250° C. to prepare a fiber-reinforced resin having an average thickness of 3 mm and a size of 600 mm×1000 mm. The properties of the shielding layer precursor and the fiber-reinforced resin are summarized in Table 1.

[0307] 3. Cold Pressed

[0308] The fiber-reinforced resin and the shielding layer precursor were heated to 220°C using an infrared heater. Then, the fiber-reinforced resin (one sheet) and the shielding layer precursor (one sheet) were stacked and placed on the molding die in such a manner that the fiber-reinforced resin was in contact with the molding lower die and the shielding layer precursor was in contact with the molding upper die. The upper die was lowered, and the fiber-reinforced resin and the shielding layer precursor were pressurized at a pressing pressure of 20 MPa (1 second from the start of pressurization to the time of reaching 20 MPa) for 1 minute, and the top face portion, the vertical face portion, and the top face portion and the vertical face portion were connected to form an integrally molded body with a corner. The results are shown in Table 1.

[0309] [Example 2]

[0310] The results are shown in Table 1.

[0311] [Example 3]

[0312] The results are shown in Table 1, except that glass fibers were mixed in a ratio of 10% by mass into the polypropylene resin of the shielding layer precursor, an integral molded body was produced in the same manner as in Example 1.

[0313] [Example 4]

[0314] The results are shown in Table 1, except that the thermoplastic resin used in the fiber-reinforced resin was polyamide 6 resin (A1030 manufactured by UNITICA CORPORATION).

[0315] [Comparative Example 1]

[0316] The metal film (aluminum foil (UACJ Foil) with a width of 20 cm and a thickness of 0.050 mm) was cut into 1000 mm without slitting and directly sandwiched between non-woven fabrics of polypropylene resin to make a shielding layer precursor. An attempt was made to use the shielding layer precursor and the same fiber-reinforced resin as in Example 1 to produce an integral molded body by cold pressing, but the aluminum foil was damaged during molding and the shielding layer could not be produced.

[0317] [Table 1]

[0318]

Claims

1. An integrally formed body, characterized in that: The invention is an integrally formed body having a fiber-reinforced resin layer and a shielding layer, wherein the fiber-reinforced resin layer comprises reinforcing fibers and a first matrix resin, The shielding layer is a layer including an aggregate of metal strips and a second matrix resin, and shields at least one of an electric field or a magnetic field. The aggregate of the metal strips includes a plurality of metal strips dispersed within the surface of the shielding layer.

2. The integrally formed body according to claim 1, wherein: The integrally formed body has a top surface portion and a vertical surface portion.

3. The integrally formed body according to any one of claims 1 or 2, wherein: When the thickness of the shielding layer is tx and the thickness of the metal belt is ty, a portion of the integrally formed body satisfies 2≤tx / ty.

4. The integrally formed body according to any one of claims 1 to 3, wherein: The mass ratio W(metal) of the aggregate of the metal tapes in the shield layer is 30% or more.

5. The integrally formed body according to any one of claims 1 to 4, wherein: The metal belt has a width of 1 mm to 40 mm, a length of 1 mm to 100 mm, and a thickness of 100 μm or less.

6. The integrally formed body according to any one of claims 1 to 5, wherein: The reinforcing fibers are discontinuous fibers and are dispersed in the in-plane direction of the fiber-reinforced resin layer.

7. The integrally formed body according to any one of claims 1 to 6, wherein: The shielding layer has a shielding property of 10 decibels or more against an electric field or a magnetic field in at least a part of a region greater than 0 MHz and not more than 3000 MHz.

8. The integrally formed body according to any one of claims 1 to 6, wherein: The shielding layer has a shielding property of 10 decibels or more against an electric field or a magnetic field in at least a part of a region of a frequency range of greater than 0 MHz and less than 100 MHz.

9. The integrally formed body according to claim 2, wherein: The thickness ta of the vertical portion and the thickness tb of the top portion satisfy ta≤tb.

10. The integrally formed body according to claim 9, wherein: The thickness of the shielding layer in the vertical portion is txa, the thickness of the fiber-reinforced resin layer in the vertical portion is ta-txa, When the thickness of the shielding layer in the top surface portion is txb and the thickness of the fiber-reinforced resin layer in the top surface portion is tb-txb, Satisfy txa≤txb and ta-txa≥tb-txb.

11. A vehicle structure, characterized in that: A one-piece molded body according to any one of claims 1 to 10.

12. A component of a battery box, characterized in that: A one-piece molded body according to any one of claims 1 to 10, The components of the battery box are arranged at the lower part of the vehicle body.

13. A method for manufacturing an integrally formed body, characterized in that: The integrally formed body is the integrally formed body according to any one of claims 1 to 10, In the method, a fiber-reinforced resin including reinforcing fibers and a first matrix resin is laminated on a shielding layer precursor and press-molded using an upper molding die and a lower molding die.

14. The method for manufacturing an integrally formed body according to claim 13, wherein: The fiber-reinforced resin and the shielding layer precursor are stacked so that the fiber-reinforced resin contacts the lower molding die, and are arranged on the lower molding die to perform press molding.

15. The method for producing an integrally formed body according to claim 13 or 14, wherein: The relationship between the ductility E1 of the fiber-reinforced resin and the ductility E2 of the laminate of the fiber-reinforced resin and the shielding layer precursor satisfies 0.9<E1 / E2<50.

16. The method for producing an integrally formed body according to any one of claims 13 to 15, wherein: The first matrix resin and the second matrix resin are thermoplastic resins.

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