JP2019064100A - Method for manufacturing radio wave transmitting cover - Google Patents

Abstract

To provide a method for manufacturing a radio wave transmission cover excellent in metal glossiness and radio wave transmission.SOLUTION: A method for manufacturing a radio wave transmission cover 10 that has a transparent resin material 12 used for an exposed part, a decorative body 14 arranged inside of the transparent resin material 12, a resin base material 16 used for an attachment part, and a metal radio transmission layer 18 arranged between the transparent resin material 12 and the resin base material 16, and has a radio radar device arranged on the back surface side includes: a step of manufacturing a laminate 28 having a metal layer 18' having a thickness of 60 nm or more and crack induction layers 20a, 20b and 22 which induces cracks on the metal layer 18'; and a step of integrally molding the transparent resin material 12, the resin base material 16 and the laminate 28, where a radio transmission layer 18 is formed by generation cracks of the metal layer 18' with a temperature and a pressure during integral molding.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a method of manufacturing a radio wave transmission cover, and more particularly, to a method of manufacturing a radio wave transmission cover suitable for a radio wave transmission cover that covers the front of a radio wave radar device such as a millimeter wave radar device.

  BACKGROUND In recent years, radio wave radar devices such as millimeter wave radar devices have attracted attention as sensor devices for detecting vehicles such as automobiles and pedestrians, obstacles, and the like. And vehicles equipped with such radio wave radar devices have been developed. Such radio wave radar devices are often disposed at the center of the front grille of a vehicle. At this position, a vehicle emblem is arranged. Therefore, the radio wave radar device may be disposed on the back side of the vehicle emblem. The emblem of the vehicle is required to have a portion having a metallic luster for design. Further, when the radio wave radar device is disposed on the back side, the radio wave transparency is also required in the portion having the metallic luster.

  For example, Patent Document 1 describes that in a radio wave transmission cover, a vapor deposition design layer of a decorative material layer for displaying a design on the outer surface thereof is formed by vapor deposition of indium or tin. Since indium and tin are deposited in the form of fine islands, radio waves can be transmitted through the gaps of the island portions. For this reason, in patent document 1, it is supposed that coexistence of metallic glossiness and radio wave permeability can be aimed at.

Patent No. 4022819

  However, the manufacturing method disclosed in Patent Document 1, which is premised on vapor deposition of fine island-shaped metals such as indium and tin in the vapor deposition design layer, has complicated processes such as insert and in-mold. , There was a problem that the processing cost would be high. In addition, since indium is a rare metal, there is also a problem that it is expensive.

  Problem to be solved by the invention is providing the manufacturing method of the electromagnetic wave transmission cover which is excellent in metallic glossiness and electromagnetic wave permeability.

  In order to solve the above problems, a method of manufacturing a radio wave transmission cover according to the present invention includes a transparent resin material to be an exposed portion, a decorative body disposed inside the transparent resin material, a resin base material to be an attachment portion, A method of manufacturing a radio wave transmission cover having a metal radio wave transmission layer disposed between the transparent resin material and the resin base material and having a radio wave radar device disposed on the back side, having a thickness of 60 nm or more. It has the process of producing the layered product which has a crack induction layer which induces a crack in a metal layer and this metal layer, and the process of carrying out integral molding of the above-mentioned transparent resin material, the above-mentioned resin base material, and the above-mentioned layered product. A gist is to form the radio wave transmission layer by generating a crack in the metal layer by the temperature and pressure at the time of molding of the integral molding.

  And the manufacturing method of the electric wave penetration cover concerning the present invention is the transparent resin material used as an appearance part, the decoration which is arranged inside the transparent resin material, the resin base material used as an attachment part, and the transparent resin material A method of manufacturing a radio wave transmission cover, comprising a metal radio wave transmission layer disposed between the metal and the resin base material, the radio wave radar device being disposed on the back side, the metal layer having a thickness of 60 nm or more, and The process of producing a layered product which has a crack induction layer which induces a crack in a metal layer, The process of arranging the layered product between the transparent resin material and the resin base material, and performing press molding Preferably, the radio wave transmission layer is formed by causing a crack in the metal layer at a temperature and pressure at the time of molding of the press molding.

  Further, in the method of manufacturing a radio wave transmission cover according to the present invention, a transparent resin material as an exposed portion, a decorative body disposed inside the transparent resin material, a resin base material as an attachment portion, and the transparent resin material A method of manufacturing a radio wave transmission cover, comprising a metal radio wave transmission layer disposed between the metal and the resin base material, the radio wave radar device being disposed on the back side, the metal layer having a thickness of 60 nm or more, and Preparing a laminate having a crack-inducing layer that induces cracks in the metal layer, and placing the laminate on one of the transparent resin material or the resin substrate, and the transparent resin relative to the disposed laminate Forming the radio wave transmission layer by causing a crack in the metal layer at a temperature and a pressure at the time of molding of the injection molding, and a step of performing the other injection molding of the material or the resin base material. There Good.

  In the present invention, it is preferable to fill the material of the crack-inducing layer in the cracks generated in the metal layer at the temperature and pressure at the time of the molding. The crack inducing layer is a thermoplastic resin layer formed from a coating liquid containing a thermoplastic resin and a solvent, and the thermoplastic resin is a thermoplastic resin having a softening temperature equal to or lower than the temperature at the time of molding. Is preferred. Further, the crack inducing layer is preferably a metal oxide layer formed by a sol-gel method. The metal of the metal layer is preferably any one or more of tin, tin alloy, aluminum, aluminum alloy, indium, indium alloy, chromium, and chromium alloy. Moreover, it is preferable that resin of the said transparent resin material is any 1 type, or 2 or more types of carbonate resin, an acrylic resin, and an olefin resin. Moreover, it is preferable that resin of the said resin base material is any 1 type, or 2 or more types of an acrylonitrile butadiene styrene resin and an acrylonitrile ethylene ethylene propylene styrene resin.

  According to the method of manufacturing a radio wave transmission cover according to the present invention, a process of producing a laminate having a metal layer having a thickness of 60 nm or more and a crack induction layer which induces a crack in the metal layer, the transparent resin material, Forming a radio wave transmission layer by causing a crack in the metal layer at a temperature and a pressure at the time of molding of the integral molding, and a step of performing integral molding of the resin base material and the laminate. A radio wave transmission cover excellent in metallic gloss and radio wave transmission can be obtained.

  Then, according to the preferred method of manufacturing a radio wave transmission cover of the present invention, a process of producing a laminate having a metal layer having a thickness of 60 nm or more and a crack inducing layer for inducing a crack in the metal layer; And disposing the laminate between the material and the resin substrate to perform press molding, wherein the metal layer is cracked by the temperature and pressure at the time of molding of the press molding. By forming the radio wave transmission layer, it is possible to obtain a radio wave transmission cover which is excellent in metallic glossiness and radio wave transmission.

  Further, according to another preferred method of manufacturing a radio wave transmission cover of the present invention, there is provided a step of producing a laminate having a metal layer having a thickness of 60 nm or more and a crack inducing layer inducing a crack in the metal layer; Placing the laminate on one of a transparent resin material or the resin substrate, and performing injection molding of the other of the transparent resin material or the resin substrate on the disposed laminate, Since the radio wave transmission layer is formed by generating a crack in the metal layer by the temperature and pressure at the time of molding, a radio wave transmission cover having excellent metallic gloss and radio wave transmission can be obtained.

  In the present invention, when the material of the crack inducing layer is filled in the cracks generated in the metal layer at the temperature and pressure at the time of molding, the gap due to the cracks generated in the metal layer is likely to be maintained without closing. This makes it easy to obtain stable radio wave transparency. And, if the crack-inducing layer is a thermoplastic resin layer formed from a coating liquid containing a thermoplastic resin and a solvent, and the thermoplastic resin is a thermoplastic resin having a softening temperature equal to or lower than the molding temperature, It is easy to induce a crack in the layer. In addition, the thermoplastic resin can be filled in the cracks generated in the metal layer. And, if the crack inducing layer is a metal oxide layer formed by a sol-gel method, it is easy to induce a crack in the metal layer. And, when the crack inducing layer includes both the thermoplastic resin layer and the metal oxide layer, it is particularly easy to induce a crack in the metal layer.

It is sectional drawing of the electromagnetic wave transmission cover which concerns on one Embodiment related to this invention. It is process drawing explaining the manufacturing method of the electromagnetic wave transmission cover which concerns on one Embodiment of this invention. It is a cross-sectional view of a radio wave transmission cover according to another embodiment related to the present invention. It is a cross-sectional view of a radio wave transmission cover according to another embodiment related to the present invention. It is process drawing explaining the manufacturing method of the electromagnetic wave transmission cover which concerns on other embodiment of this invention. It is the surface photography of the metal layer (Al layer) of the electromagnetic wave transmission cover of an Example and a comparative example. It is the surface photography of the metal layer (In layer) of the electromagnetic wave transmission cover of an Example and a comparative example. It is the surface photography of the metal layer (Sn layer) of the electromagnetic wave transmission cover of an Example and a comparative example.

  The method of manufacturing the radio wave transmission cover according to the present invention will be described in detail.

  FIG. 1 is a cross-sectional view of a radio wave transmission cover according to an embodiment of the present invention. FIG. 2 is a process diagram for explaining a method of manufacturing a radio wave transmission cover according to an embodiment of the present invention.

  As shown in FIG. 1, the radio wave transmission cover 10 according to one embodiment includes a transparent resin material 12 serving as an exposed portion, a decorative body 14 disposed inside the transparent resin material 12, and a resin base material serving as an attachment portion. 16. A metal radio wave transmission layer 18 disposed between the transparent resin material 12 and the resin base material 16 is provided, and a radio wave radar device such as a millimeter wave radar device is provided on the back side (the resin base material 16 side) It is The radio wave transmission cover 10 is disposed, for example, at the center of a front grill of a vehicle. The radio wave transmission cover 10 is applicable not only to the vehicle but also to products requiring metallic gloss and radio wave transmission.

  The radio wave transmission cover 10 according to the embodiment has metal oxide layers 20a and 20b formed of a metal oxide film formed by a sol-gel method on both sides of the metal radio wave transmission layer 18. Further, a thermoplastic resin layer 22 containing a thermoplastic resin and a base film 24 are provided in order on the outer side of the other metal oxide layer 20 b with respect to the radio wave transmission layer 18. Furthermore, adhesive layers 26 a and 26 b are provided on the outside of one metal oxide layer 20 a with respect to the radio wave transmission layer 18 and on the outside of the base film 24 with respect to the thermoplastic resin layer 22. That is, from the resin base 16 side, the resin base 16, the adhesive layer 26b, the base film 24, the thermoplastic resin layer 22, the metal oxide layer 20b, the radio wave transmission layer 18, the metal oxide layer 20a, the adhesive layer 26a And the transparent resin material 12 are arrange | positioned.

  The transparent resin material 12 is a portion that appears on the front side (outside) of the radio wave transmission cover 10 and serves as an exposed portion. The material of the transparent resin material 12 is not particularly limited as long as it is a transparent resin. Examples of the transparent resin material 12 include carbonate resin, acrylic resin, and olefin resin. Among these, carbonate resins and acrylic resins are preferable from the viewpoint of excellent scratch resistance and transparency. Further, a carbonate resin is preferable from the viewpoint of excellent impact resistance and the like. In addition, an olefin resin is preferable from the viewpoint of being able to suppress the attenuation of radio waves by using a resin having a relatively low dielectric constant. As an olefin resin, polyethylene, polypropylene, an ethylene-alpha olefin copolymer, a cycloolefin polymer etc. are mentioned.

  The decorative body 14 constitutes a design of the radio wave transmission cover 10 together with the metal radio wave transmission layer 18, and has a predetermined pattern. For example, in the case where the metal of the radio wave transmission layer 18 constitutes a predetermined mark, the decorative body 14 has a pattern formed of a portion other than the predetermined mark.

  The resin base 16 is an attachment portion of the radio wave transmission cover 10. The resin base 16 is a portion hidden behind (inside) the radio wave transmission cover 10 and is disposed apart from the transparent resin material 12. As the resin base material 16, a thermoplastic resin is mentioned, for example. And as a suitable thermoplastic resin, an ABS resin (acrylonitrile butadiene styrene copolymer), an AES resin (acrylonitrile ethylene propylene diene styrene copolymer), nylon resin, polyoxymethylene (POM), polybutylene A terephthalate (PBT), modified polyphenylene ether (m-PPE), etc. are mentioned.

  The radio wave transmission layer 18 constitutes the design of the radio wave transmission cover 10 together with the decorative body 14, is a part that expresses the texture of metal, and is made of metal. The radio wave transmission layer 18 is made of a metal layer having a crack, and has a radio wave transmission property as well as expressing the texture of the metal by having a crack. The radio wave transmission layer 18 has a thickness of 60 nm or more in order to make the radio wave transmission cover 10 a part that expresses the texture of metal. If the thickness is less than 60 nm and relatively thin, it is difficult to express the texture of the metal. The metal of the radio wave transmission layer 18 is not particularly limited, but tin, tin alloy, aluminum, aluminum alloy, indium, indium alloy, chromium, chromium alloy, silver, silver alloy, from the viewpoint of being more excellent in appearance etc. Nickel, nickel alloy, stainless steel, titanium, zinc, tantalum and the like are preferable. For example, aluminum has a mirror-like appearance. Indium has a whitish mirror-like appearance. Chromium has a blue, dark metallic appearance. Tin has the appearance of a yellow metallic color. Among these, tin, tin alloy, indium, and indium alloy tend to be granular at the time of film formation, and there is an advantage that radio wave permeability is improved by utilizing gaps between particles. The radio wave transmission layer 18 may be formed of a metal layer having two or more cracks, for example, from the viewpoint of expressing various metal textures. For example, a metal layer made of indium becomes a whitish mirror surface, and by laminating a metal layer made of aluminum on this, the texture of aluminum can be added.

  The radio wave transmission cover 10 according to the one embodiment can be manufactured by the method of manufacturing the radio wave transmission cover according to the one embodiment of the present invention.

  In a method of manufacturing a radio wave transmission cover according to an embodiment of the present invention, a step of producing a predetermined laminate, and a step of disposing the laminate between a transparent resin material and a resin base and performing press molding And.

  As shown in FIG. 2A, the laminate 28 has a thermoplastic resin layer 22, a metal oxide layer 20b, a metal layer 18 ', and a metal oxide layer 20a on the surface of the base film 24. , Are sequentially stacked. The metal layer 18 ′ in the laminate is a layer in which a crack does not occur before the crack occurs. The metal layer 18 ′ has a thickness of 60 nm or more in order to make the radio wave transmission cover 10 a part that expresses the texture of the metal. The thermoplastic resin layer 22 contains a thermoplastic resin having a softening temperature equal to or lower than the temperature at the time of press molding. The metal oxide layers 20a and 20b are formed by a sol-gel method. The laminate 28 forms the thermoplastic resin layer 22 on the surface of the base film 24, forms the metal oxide layer 20b on the surface of the thermoplastic resin layer 22, and forms the metal on the surface of the metal oxide layer 20b. It can be produced by forming the layer 18 'and forming the metal oxide layer 20a on the surface of the metal layer 18'.

  The thermoplastic resin layer 22 can be formed by preparing a coating liquid containing a thermoplastic resin and a solvent, coating the coating liquid on the surface of the base film 24, and drying it to form a film. The metal oxide layers 20a and 20b prepare a coating liquid containing an organometallic compound to be a precursor of a metal oxide, and coat this on the surface of the thermoplastic resin layer 22 or the surface of the metal layer 18 '. After processing, it can be dried to form a membrane, and the organic metal compound in the membrane can be formed by hydrolysis and condensation reaction. The metal layer 18 'is formed by physical vapor deposition (PVD) such as vacuum evaporation, sputtering, ion plating, MBE, laser ablation, etc., or chemical vapor deposition such as thermal CVD, plasma CVD, etc. It can be formed on the surface of the metal oxide layer 20b by using a vapor phase method such as CVD (CVD).

  Next, as shown in FIG. 2 (b), the laminate 28 is disposed between the transparent resin material 12 and the resin base 16. Adhesives (adhesion layers 26a and 26b) are disposed between the laminate 28 and the transparent resin material 12 and between the laminate 28 and the resin base 16, respectively. As the adhesive, a heat fusible resin can be used. The heat fusible resin may be in the form of a sheet. The transparent resin material 12 and the resin base material 16 can use what was shape | molded previously to the predetermined | prescribed shape. A decorative body 14 having a predetermined pattern is formed in advance on the inner side surface of the transparent resin material 12. The decorative body 14 can be formed by applying a coating material to the inner surface of the transparent resin material 12 and then drying it to form a film. The decorative body 14 may be formed on the surface of the metal oxide layer 20 a of the laminate 28.

  Next, as shown in FIG. 2C, press molding is performed. Press molding can be performed by, for example, a vacuum press. The press molding is performed at a temperature lower than the heat deformation temperature of the transparent resin material 12 and the resin base 16. For example, when a polycarbonate resin is used as the transparent resin material 12 and an ABS resin is used as the resin base 16, it is preferable to perform press molding at 105 ° C. or less in consideration of the heat deformation temperature of the ABS resin. In this case, the pressurizing condition is preferably 40 kN or more. Moreover, it is preferable that it is 5 minutes or more as pressurization time.

  As shown in FIG. 2, when the laminate 28 is placed between the transparent resin material 12 and the resin base 16 and press molding is performed, cracks are generated in the metal layer 18 'at the temperature and pressure at the time of molding. be able to. Thereby, the radio wave transmission layer 18 formed of a metal layer having a crack can be formed. This is because the metal oxide layers 20a and 20b and the thermoplastic resin layer 22 of the laminate 28 function as a crack-inducing layer that induces cracks in the metal layer 18 '. When the metal oxide layers 20a and 20b are formed by the sol-gel method, strain remains due to their curing shrinkage, and they have high residual stress. Under the influence of this residual stress, a crack is generated in the metal layer 18 'at the time of press forming. If the metal oxide layers 20a and 20b are broken before press forming, the stress is released before the press forming depending on the degree of the cracks, so the metal layer 18 'can not be broken at the time of press forming. The metal layer 18 'is relatively thick at 60 nm or more. For this reason, the metal layer 18 ′ is not broken by the stress when the metal oxide layers 20 a and 20 b are broken before press forming. In addition, when the thermoplastic resin layer 22 is formed from a coating liquid containing a thermoplastic resin and a solvent, distortion of the film remains due to film contraction and has high residual stress. Under the influence of this residual stress, a crack is generated in the metal layer 18 'at the time of press forming. If the softening temperature of the thermoplastic resin of the thermoplastic resin layer 22 is higher than the temperature at the time of press molding, the stress of the thermoplastic resin layer 22 is not released at the time of press molding, and the metal layer 18 'can not be broken at the time of press molding. . When the thermoplastic resin layer 22 contains a thermoplastic resin having a softening temperature equal to or lower than the temperature at the time of press molding, the residual stress of the thermoplastic resin layer 22 as well as the heat and pressure at the time of the molding give a large strain to the metal layer 18 ′. As a result, the metal layer 18 'is cracked.

  The thermoplastic resin layer 22 preferably has a relatively large thickness in view of the fact that shrinkage of the film at the time of film formation becomes large, tends to have high residual stress, and easily causes a crack in the metal layer 18 ′. From this point of view, the thickness of the thermoplastic resin layer 22 is preferably 0.5 μm or more. More preferably, it is 1.5 μm or more. On the other hand, the thickness of the thermoplastic resin layer 22 is preferably 10.0 μm or less from the viewpoint of processability, cost and the like. More preferably, it is 5.0 μm or less. The thickness of the thermoplastic resin layer 22 can be adjusted by the type of material, the viscosity, the amount of solvent, and the like.

  The metal oxide layers 20a and 20b have large shrinkage of the film at the time of film formation, tend to have high residual stress, and easily cause cracks in the metal layer 18 ', and reflected color tint (red, yellow, blue) It is preferable to be relatively thick from the viewpoint of From this viewpoint, the thickness of the metal oxide layers 20a and 20b is preferably 10 nm or more. More preferably, it is 20 nm or more. In addition, since the stress becomes strong when the film thickness is large, it is easy to prevent the metal oxide layers 20a and 20b from being cracked and released from stress by stress during film formation before press molding (red, yellow, etc. , Blue) and the like, the thickness of the metal oxide layers 20a and 20b is preferably 100 nm or less. More preferably, it is 50 nm or less. The thickness of the metal oxide layers 20a and 20b can be adjusted by the type of material, the viscosity, the amount of solvent, and the like.

  The metal of the metal layer 18 'is not particularly limited in terms of generating a crack. In the present invention, a crack can be generated in a metal layer made of a versatile metal. There is a difference in the ease of occurrence of cracks depending on the metal species. The softer the metal, the less likely it is to crack. For example, in comparison of Mohs hardness, it is hard in the order of chromium (9.0), aluminum (2.9), tin (1.8) and indium (1.2). Relatively hard chromium is a metal that is relatively susceptible to cracking, while relatively soft tin, indium, and aluminum are metals that are relatively resistant to cracking. In addition, aluminum has a relatively high stretchability, so it is difficult to propagate even if a crack occurs. Because of this, the cracks tend to be relatively coarse. On the other hand, since tin and indium have lower ductility than aluminum, they easily propagate when a crack occurs. Because of this, the cracks tend to be relatively fine.

  In the method of manufacturing the radio wave transmission cover according to one embodiment of the present invention, since the metal oxide layers 20a and 20b and the thermoplastic resin layer 22 function as a crack inducing layer, tin and indium which are relatively difficult to crack are generated. The metal layer 18 'made of aluminum or the like can also be sufficiently cracked.

In the method of manufacturing a radio wave transmission cover according to an embodiment of the present invention, the laminate 28 disposed between the transparent resin material 12 and the resin base 16 is made of the following (1). The laminate disposed between the transparent resin material 12 and the resin base 16 is not limited to this. The laminate may have, for example, the following (2) to (6).
(1) Base film 24 / thermoplastic resin layer 22 / metal oxide layer 20b / metal layer 18 '/ metal oxide layer 20a
(2) base film / metal oxide layer / metal layer / metal oxide layer / thermoplastic resin layer (3) base film / thermoplastic resin layer / metal oxide layer / metal layer (4) base film / Thermoplastic resin layer / metal layer / metal oxide layer (5) base film / metal oxide layer / metal layer / thermoplastic resin layer (6) base film / metal layer / metal oxide layer / thermoplastic resin layer

  The laminate 28 may have a surface protective layer on the outermost layer opposite to the base film 24 from the viewpoint of handleability and the like. By having the surface protective layer, the metal oxide layer 20a is not exposed to the surface, so the scratch resistance of the laminate 28 is improved. Also in the laminated body of the laminated constitution of said (2)-(6), you may have a surface protective layer in the outermost layer on the opposite side to a base film similarly.

  In the method of manufacturing the radio wave transmission cover according to one embodiment of the present invention, the crack induction layer in the laminate 28 is composed of both the metal oxide layers 20a and 20b and the thermoplastic resin layer 22, but the crack induction layer is It may be composed of either one of the metal oxide layers 20 a and 20 b and the thermoplastic resin layer 22.

  When the laminate contains a thermoplastic resin layer but does not contain a metal oxide layer, and the crack-inducing layer is composed of a thermoplastic resin layer, the radio wave transmission cover after press molding is shown in FIG. It becomes the composition of 3. The radio wave transmission cover 30 shown in FIG. 3 includes, in order from the resin base 16 side, the resin base 16, the adhesive layer 26b, the base film 24, the thermoplastic resin layer 22, the radio wave transmission layer 18, the adhesive layer 26a, a decorative body 14, the transparent resin material 12 is disposed.

  If the laminate contains a metal oxide layer but does not contain a thermoplastic resin layer, and the crack-inducing layer is composed of a metal oxide layer, the radio wave transmission cover after press molding is shown in the figure. It becomes the composition of 4. The radio wave transmission cover 40 shown in FIG. 4 includes, in order from the resin base 16 side, the resin base 16, the adhesive layer 26b, the base film 24, the metal oxide layer 20b, the radio wave transmission layer 18, the metal oxide layer 20a, The layer 26a, the decorative body 14, and the transparent resin material 12 are disposed.

  As shown in FIG. 3 and FIG. 4, even if one of the metal oxide layers 20 a and 20 b and the thermoplastic resin layer 22 is not included in the laminate, the transparent resin material 12 and the resin base 16 When the laminate is placed between and pressed for forming, cracks can be generated in the metal layer 18 'at the temperature and pressure at the time of forming. Thereby, the radio wave transmission layer 18 can be formed. However, both of the metal oxide layers 20a and 20b and the thermoplastic resin layer 22 in the laminate are more than those in which one of the metal oxide layers 20a and 20b and the thermoplastic resin layer 22 is not included in the laminate. The inclusion is more likely to cause the metal layer 18 'to crack. Further, when the metal layer 18 ′ is other than indium, the metal oxide layers 20 a and 20 b are included more than the metal oxide layers 20 a and 20 b and the thermoplastic resin layer 22 not including the thermoplastic resin layer 22. It is easier for the metal layer 18 'to crack if it is not. In FIG. 4, the metal oxide layers 20a and 20b are disposed on both sides of the metal layer 18 ', but the metal oxide layer is disposed on any one of the two surfaces of the metal layer 18'. It may be one.

  When the thermoplastic resin layer 22 is included in the laminate, the thermoplastic resin of the thermoplastic resin layer 22 is a thermoplastic resin having a softening temperature equal to or lower than the temperature at the time of molding. Since the thermoplastic resin of the thermoplastic resin layer 22 enters (fills) in the cracks generated in the metal layer 18 ′, the gap due to the cracks generated in the metal layer 18 ′ is likely to be maintained without closing. This makes it easy to obtain stable radio wave transparency. When the thermoplastic resin layer 22 is not included in the laminate, the thermoplastic resin of the thermoplastic resin layer 22 does not maintain the cracks (gaps) generated in the metal layer 18 ′, but the metal layer 18 ′ or metal oxide In the configuration in which the adhesive layers 26a and 26b are in contact with the object layers 20a and 20b, the adhesive enters (fills) in the cracks generated in the metal layer 18 ', so the gaps caused by the cracks in the metal layer 18' close. Not easy to maintain. This makes it easy to obtain stable radio wave transparency.

  In the radio wave transmission layer 18, the width of the cracks and the number of cracks affect the radio wave transmission. The greater the width of the cracks, the greater the number of cracks, the better the radio wave transmission. The number of cracks can be assessed by the distance between the cracks. The smaller the distance between the cracks, the greater the number of cracks. From the viewpoint of radio wave permeability, the width of the crack is preferably 20 μm or more. On the other hand, in terms of appearance, the width of the crack is preferably 100 μm or less.

  In the method of manufacturing a radio wave transmission cover according to the present invention, injection molding can be performed instead of press molding.

  In the method of manufacturing a radio wave transmission cover according to another embodiment of the present invention, a process of producing a predetermined laminate for one of a transparent resin material or a resin substrate, and a transparent resin material or a resin substrate for the laminate And b) performing the other injection molding. Below, a transparent resin material is made into one side, and a resin base material is demonstrated as the other. Of course, in the method of manufacturing the radio wave transmission cover according to another embodiment of the present invention, the transparent resin material may be the other and the resin base may be one.

  As shown to Fig.5 (a), the transparent resin material 12 currently shape | molded previously to the predetermined | prescribed shape is prepared. The transparent resin material 12 can be obtained, for example, as one molded into a predetermined shape by injection molding or the like. A decorative body 14 having a predetermined pattern is formed in advance on the inner side surface of the transparent resin material 12. The decorative body 14 can be formed by applying a coating material to the inner surface of the transparent resin material 12 and then drying it to form a film.

  Then, as shown in FIG. 5 (b), a metal oxide layer 20 a, a metal layer 18 ′, and a metal oxide layer 20 b are formed on the inner side surface of the transparent resin material 12 where the decorative body 14 is formed. The thermoplastic resin layer 22 is sequentially laminated. Thereby, a laminate 52 having the metal oxide layer 20 a, the metal layer 18 ′, the metal oxide layer 20 b, and the thermoplastic resin layer 22 is produced for the transparent resin material 12. The formation method of each layer should just follow the formation method of each layer of the laminated body 28 in the said press molding. Similar to the laminate 28 in the above-described press forming, the metal layer 18 ′ in the laminate 52 is a layer in which no crack occurs before the crack occurs. The metal layer 18 ′ has a thickness of 60 nm or more in order to provide a portion of the radio wave transmission cover 50 for expressing the texture of the metal. The thermoplastic resin layer 22 is formed from a coating liquid containing a thermoplastic resin and a solvent, and includes a thermoplastic resin having a softening temperature equal to or lower than the temperature at the time of press molding. The metal oxide layers 20a and 20b are formed by a sol-gel method.

  Next, as shown in FIG. 5 (b), an adhesive (adhesive layer 26 b) is disposed on the surface of the laminate 52. As the adhesive, a heat fusible resin can be used. The heat fusible resin may be in the form of a sheet. Next, as shown in FIG. 5C, injection molding of the resin base 16 is performed on the laminate 52 through the adhesive layer 26b. In the injection molding, in a state where the resin of the resin base 16 is melted, the laminate 52 is injected at a predetermined pressure. Therefore, the injection molding is performed at a predetermined pressure at a temperature higher than the melting temperature of the resin of the resin base 16. Cracks can be generated in the metal layer 18 'at the temperature and pressure at the time of injection molding. Thereby, the radio wave transmission layer 18 formed of a metal layer having a crack can be formed. This means that the metal oxide layers 20a and 20b and the thermoplastic resin layer 22 of the laminate 52 function as a crack-inducing layer that induces a crack in the metal layer 18 'also in the injection molding as in the above-described press molding. It is for.

  In the method of manufacturing the radio wave transmission cover according to another embodiment of the present invention, since the metal oxide layers 20a and 20b and the thermoplastic resin layer 22 function as a crack inducing layer, tin or the like which is relatively difficult to be cracked is produced. The metal layer 18 'made of indium, aluminum or the like can also be sufficiently cracked.

In the method of manufacturing a radio wave transmission cover according to another embodiment of the present invention, the laminated body 52 is formed of the following laminated structure (7) (Laminated structure from the transparent resin material 12 side), but as a laminated body in injection molding Is not limited to this. The laminate may have, for example, the following (8) to (12).
(7) Metal oxide layer 20a / metal layer 18 '/ metal oxide layer 20b / thermoplastic resin layer 22
(8) Thermoplastic resin layer / metal oxide layer / metal layer / metal oxide layer (9) metal oxide layer / metal layer / thermoplastic resin layer (10) metal layer / metal oxide layer / thermoplastic resin layer (11) Thermoplastic resin layer / metal oxide layer / metal layer (12) Thermoplastic resin layer / metal layer / metal oxide layer

  The laminate 52 may have a surface protective layer on the outermost layer on the side opposite to the transparent resin material 12 from the viewpoint of handleability and the like. By having the surface protective layer, the thermoplastic resin layer 22 is not exposed to the surface, so the scratch resistance of the laminate 52 is improved. Also in the laminated body of the laminated constitution of said (8)-(12), you may have a surface protective layer in the outermost layer on the opposite side to a transparent resin material similarly.

  Since each layer of the laminate 52 in injection molding is laminated on the transparent resin material 12 or the resin substrate 16, the substrate film 24 is not used as in the laminate 28 in press molding, and the substrate film 24 is used. It can be omitted. Moreover, an adhesive is unnecessary between the transparent resin material 12 or the resin base 16 and the laminate 52, and the adhesive can be omitted.

  In the method of manufacturing the radio wave transmission cover according to another embodiment of the present invention, the crack induction layer in the laminate 52 is composed of both the metal oxide layers 20a and 20b and the thermoplastic resin layer 22, but the crack induction layer May be composed of either the metal oxide layers 20 a, 20 b or the thermoplastic resin layer 22. Even if the laminate does not contain any one of the metal oxide layers 20a and 20b and the thermoplastic resin layer 22, if injection molding of the resin base 16 or the transparent resin material 12 is performed on the laminate, Cracks can be generated in the metal layer 18 'at the forming temperature and pressure. Thereby, the radio wave transmission layer 18 can be formed. However, a laminate in which both the metal oxide layers 20 a and 20 b and the thermoplastic resin layer 22 are included rather than a laminate not including any one of the metal oxide layers 20 a and 20 b and the thermoplastic resin layer 22 The body is more likely to crack the metal layer 18 '. In addition, in the case of other than indium, a laminate in which the metal oxide layers 20a and 20b are not included in the metal oxide layers 20a and 20b and the thermoplastic resin layer 22 than the laminate in which the thermoplastic resin layer 22 is not included. Is more likely to cause a crack in the metal layer 18 '.

  Also in the method of manufacturing the radio wave transmission cover according to another embodiment of the present invention, when the thermoplastic resin layer 22 is included in the laminate, the thermoplastic resin of the thermoplastic resin layer 22 is softened at a temperature equal to or lower than the molding temperature. Since it is a thermoplastic resin of temperature, the thermoplastic resin of the thermoplastic resin layer 22 enters (fills) in the cracks generated in the metal layer 18 ′ at the temperature and pressure at the time of molding, so the metal layer 18 It is easy to maintain the gap caused by the crack that 's not closed. This makes it easy to obtain stable radio wave transparency. When the thermoplastic resin layer 22 is not included in the laminate, the thermoplastic resin of the thermoplastic resin layer 22 does not maintain the cracks (gaps) generated in the metal layer 18 ′, but the metal layer 18 ′ or metal oxide In the configuration in which the resin of the transparent resin material 12 or the resin base material 16 is injected to the object layers 20a and 20b, the injected resin enters (fills) in the cracks generated in the metal layer 18 '. It is easy to maintain the gap caused by the crack that 's not closed. This makes it easy to obtain stable radio wave transparency.

  In the above-mentioned embodiment, although press molding and injection molding are explained as a molding method, the present invention may be molding methods other than these molding methods. For example, other forming methods such as ultrasonic welding may be used.

  Next, the metal layer 18 ', the thermoplastic resin layer 22, the metal oxide layers 20a and 20b, the base film 24, the adhesive layers 26a and 26b, and the surface protective layer will be described.

  The metal of the metal layer 18 ′ is the same as the metal of the radio wave transmission layer 18, and is not particularly limited, but chromium, chromium alloy, tin, tin alloy, aluminum, aluminum alloy, indium, indium alloy, silver, Silver alloy, nickel, nickel alloy, stainless steel and the like are preferable.

  As a thermoplastic resin of the thermoplastic resin layer 22, an acrylic resin, a styrene resin, a styrene-type elastomer, etc. are mentioned. The styrenic elastomer is composed of a polystyrene block serving as a hard segment and an elastomer block having a polyolefin structure serving as a soft segment. As the styrene-based elastomer, styrene-ethylene-propylene-styrene block copolymer (SEPS), styrene-ethylene-butylene-styrene block copolymer (SEBS), styrene-ethylene-propylene copolymer (SEP), or Styrene-ethylene-ethylene-butylene-styrene block copolymer (SEEP) etc. are mentioned. For example, when the thermoplastic resin layer 22 is a layer in contact with the transparent resin material 12 or the resin base material 16, it is preferable to select a resin having excellent adhesion to the transparent resin material 12 or the resin base material 16. When the material of the member in contact with the thermoplastic resin layer 22 is an acrylic resin, the thermoplastic resin of the thermoplastic resin layer 22 is preferably an acrylic resin. When the material of the member in contact with the thermoplastic resin layer 22 is an ABS resin, the thermoplastic resin of the thermoplastic resin layer 22 is preferably a styrene resin or a styrene elastomer.

  In preparation of the coating liquid containing a thermoplastic resin, the solvent which melt | dissolves a thermoplastic resin can be used as needed. Such solvents include alcohols such as methanol, ethanol, propanol, butanol, heptanol and isopropyl alcohol, organic acid esters such as ethyl acetate, ketones such as acetonitrile, acetone and methyl ethyl ketone, and cycloethers such as tetrahydrofuran and dioxane And acid amides such as formamide and N, N-dimethylformamide; hydrocarbons such as hexane; and aromatics such as toluene and xylene. One or more of these may be mixed.

  In the metal oxide layers 20a and 20b, examples of the organic metal compound to be a precursor of the metal oxide include metal alkoxides, metal acylates, and metal chelates. Among these, metal chelates are preferable from the viewpoint of excellent stability of the coating liquid. The metal chelate is one in which a chelating agent (chelating ligand) is coordinated to a metal or metal ion, and may be complexed in advance, or other organic metal compounds such as metal alkoxides and metal acylates. Alternatively, a predetermined amount of a chelating agent (chelating ligand) may be blended to form a complex.

  The metal chelate is stabilized by a chelating agent (chelating ligand), and the hydrolysis / condensation reaction is suppressed. As a means for hydrolyzing and condensing such a metal chelate, irradiation of light energy such as ultraviolet light, electron beam, and X-ray can be used. In this case, as a chelating agent (chelating ligand), a light absorbing (for example, ultraviolet absorbing) one is used. When the organometallic compound is a metal chelate, a sol-gel method using light energy at the time of sol-gel curing can be employed. Among light energy, ultraviolet light is preferable from the viewpoint of being able to generate a metal oxide at a low temperature and in a short time, and to prevent a load due to heat from being applied to the base film 24.

It is preferable that the light quantity of the light energy irradiated to a metal oxide precursor is 250 mJ / cm < ² > or less in consideration of the heat resistance of the base film 24. As shown in FIG. On the other hand, when the amount of light energy is too small, the hydrolysis / condensation reaction of the metal oxide precursor does not proceed sufficiently. Therefore, from this viewpoint, the light quantity of light energy is preferably 100 mJ / cm ² or more.

  As a UV absorbing chelating agent (chelating ligand), β-diketones, alkoxy alcohols, alkanolamines and the like can be mentioned. Examples of β-diketones include acetylacetone, benzoylacetone, ethyl acetoacetate, methyl acetoacetate, diethyl malonate and the like. Examples of the alkoxy alcohol include 2-methoxyethanol, 2-ethoxyethanol, 2-methoxy-2-propanol and the like. Examples of alkanolamines include monoethanolamine, diethanolamine, triethanolamine and the like. One or more of these may be mixed.

  The coating liquid may contain a solvent. As the solvent, alcohols such as methanol, ethanol, propanol, butanol, heptanol and isopropyl alcohol, organic acid esters such as ethyl acetate, acetonitrile, ketones such as acetone and methyl ethyl ketone, cycloethers such as tetrahydrofuran and dioxane, formamide, Acid amides such as N, N-dimethylformamide, hydrocarbons such as hexane, and aromatics such as toluene. One or more of these may be mixed.

  Since the chelating agent (chelating ligand) and the solvent are components that can be the organic residue of the metal oxide layers 20a and 20b, from the viewpoint of reducing the amount of organic residues in the metal oxide layers 20a and 20b, It is preferable that these are components which are relatively volatile at the time of sol-gel curing. As a chelating agent (chelating ligand), acetylacetone, ethyl acetoacetate, methyl acetoacetate and the like are preferable from the viewpoint of reducing the stability of the metal oxide precursor and the amount of organic residue. Moreover, as a solvent, methanol, ethanol, propanol, butanol, isopropyl alcohol etc. are preferable from a viewpoint of reducing the amount of organic residues. Further, from the viewpoint of reducing the amount of metal oxide precursor and organic residue, butanol, isopropyl alcohol and the like are preferable. And as a combination of a chelating agent (chelating ligand) and a solvent, the combination of acetylacetone butanol, the combination of acetylacetone isopropyl alcohol, and the mixed solvent of acetylacetone butanol-isopropyl alcohol are preferable.

  As metal oxides of the metal oxide layers 20a and 20b, oxides of titanium, oxides of silicon, oxides of zinc, oxides of indium, oxides of tin, oxides of indium and tin, oxides of magnesium , Oxides of aluminum, oxides of zirconium, oxides of niobium, oxides of cerium, and the like. One or more of these may be contained. Also, these metal oxides may be complex oxides in which two or more metal oxides are complexed. Among these, oxides of titanium and oxides of silicon are preferable from the viewpoint of being relatively hard, brittle and easily broken.

  As the organic titanium compound, specifically, for example, an M—O—R bond (R represents an alkyl group, such as tetra-n-butoxytitanium, tetraethoxytitanium, tetra-i-propoxytitanium, tetramethoxytitanium, etc. M represents an alkoxide of titanium having a titanium atom, an acylate of titanium having an M-O-CO-R bond (R represents an alkyl group, M represents a titanium atom) such as isopropoxy titanium stearate, or Examples thereof include chelates of titanium such as diisopropoxytitanium bisacetylacetonate, dihydroxybislactate titanium, diisopropoxybistriethanolaminatotitanium, diisopropoxybisethylacetoacetate titanium and the like. One or more of these may be mixed. These may be either monomers or multimers.

  As the coating method, various types such as microgravure method, gravure method, reverse roll coating method, die coating method, knife coating method, dip coating method, spin coating method, bar coating method, etc. from the viewpoint of easy uniform coating. The wet coating method of can be exemplified as a suitable method. These can be appropriately selected and used, and may be used alone or in combination of two or more.

  The base film 24 may be a resin film. The resin of the base film 24 may be polyethylene terephthalate (PET), polycarbonate, polymethyl methacrylate, polyethylene, polypropylene, ethylene-α-olefin copolymer, cycloolefin polymer, ethylene-vinyl acetate copolymer, polystyrene, polyamide, Polybutylene terephthalate, polyetheretherketone, polyvinyl chloride, polyvinylidene chloride, triacetyl cellulose, polyurethane, cellulose nanofibers and the like can be mentioned. Among them, polyethylene terephthalate, polycarbonate, polymethyl methacrylate, polyethylene, polypropylene, ethylene-vinyl acetate copolymer, polystyrene, and the like from the viewpoint of high rigidity and easy transfer of the pressure of press molding to the metal layer 18 ′. Polyimide, polyamide, polybutylene terephthalate, polyethylene naphthalate, polysulfone, polyether sulfone, polyether ether ketone, polyvinyl alcohol, polyvinyl chloride, polyvinylidene chloride, triacetyl cellulose, polyurethane, and cycloolefin polymer are preferable. The film is in the form of a thin film and generally has a thickness of 200 μm or less or 250 μm or less. What is necessary is just to have a degree of flexibility enough to be rolled, and as such, it may be 200 μm or more or 250 μm or more thick. The film is generally delivered as a roll.

  The thickness of the base film 24 is not particularly limited, but is preferably 10 μm or more from the viewpoint of durability and the like. More preferably, it is 15 micrometers or more, More preferably, it is 20 micrometers or more. Moreover, it is preferable that it is 100 micrometers or less from a viewpoint of being excellent in productivity in roll to roll etc. More preferably, it is 50 μm or less.

  Examples of the adhesive for the adhesive layers 26a and 26b include polyvinyl butyral (PVB). The thickness of the adhesive layers 26a and 26b is not particularly limited, but is preferably 50 μm or more from the viewpoint of adhesiveness and the like. More preferably, it is 100 μm or more. Moreover, it is preferable that it is 500 micrometers or less from a viewpoint of cost, transparency, processability, etc. More preferably, it is 250 μm or less.

  The surface protective layer can be made of a curable resin, an organic-inorganic hybrid material, or the like. The curable resin may, for example, be a silicone resin or an acrylic resin. The silicone resin or acrylic resin may be thermosetting, photocurable, or water curable. Examples of acrylic resins include acrylic urethane resins, silicone acrylic resins, and acrylic melamine resins.

  Examples of the organic-inorganic hybrid material include those in which inorganic particles are blended in an organic material. As an organic material in this case, curable resin is mentioned. As a curable resin, an acrylic resin, an epoxy resin, a urethane resin, etc. are mentioned. These may be used alone or in combination of two or more. Among these, acrylic resin and urethane resin are preferable in view of transparency, flexibility and the like. In addition, as the inorganic particles in this case, metal particles, metal oxide particles and the like can be mentioned. Among these, metal oxide particles are preferable in terms of light transparency and the like. Examples of the metal of the metal particles and the metal oxide particles include Si, Ti, and Zr. As the inorganic particles, silica particles are preferable from the viewpoints of abrasion resistance, abrasion resistance, versatility and the like. As the inorganic particles, nanoparticles are used from the viewpoint of dispersibility, light transmittance, and the like. Nanoparticles are nano-sized inorganic particles with a particle size of less than 1 μm. In this case, the inorganic particles become the inorganic component in the surface protective layer.

  In addition, as the organic-inorganic hybrid material, those which are formed of an organic material (raw material of organic component) and an inorganic material (raw material of inorganic component), and the organic material and the inorganic material are complexed at nano level or molecular level are mentioned Be Such an organic-inorganic hybrid material is, for example, a network in which an inorganic material dispersed in an organic material and an organic material cause a reaction such as a polymerization reaction, and an inorganic component is highly dispersed in the organic component through a chemical bond. And a cross-linked structure of As an organic material in this case, curable resin is mentioned. As a curable resin, an acrylic resin, an epoxy resin, a urethane resin, etc. are mentioned. These may be used alone or in combination of two or more. Moreover, a metal compound etc. are mentioned as an inorganic material in this case. Examples of the metal compound include Si compounds, Ti compounds, and Zr compounds. These may be used alone or in combination of two or more. Among these, Si compounds are more preferable from the viewpoints of abrasion resistance, abrasion resistance, versatility and the like. The metal compound is a compound containing an inorganic component such as Si, Ti, or Zr, and is made of a compound that can be complexed by causing a reaction such as a polymerization reaction with a raw material of the organic component. More specifically, examples of the metal compound include organic metal compounds. Examples of the organic metal compound include silane coupling agents, metal alkoxides, metal acylates, metal chelates and silazanes.

  Hereinafter, the present invention will be described in detail by way of examples and comparative examples.

Example 1
The layered product 1 which has a thermoplastic resin layer, a metal oxide layer, a metal layer, and a metal oxide layer in order was produced on the field of a substrate film. The laminate 1 was disposed between a transparent resin material and a resin base material, and press molding was performed to produce a radio wave transmission cover. The details are as follows.

(Preparation of Coating Liquid A)
The thermoplastic resin (acrylic resin) was diluted with a solvent (butyl acetate) to a solid content concentration of 18% by mass, to prepare a coating liquid A for forming a thermoplastic resin layer.
Acrylic resin: manufactured by Soken Chemical Co., Ltd., trade name "Thermolac M-45C", softening temperature 105 ° C

(Preparation of Coating Liquid B)
Sol-gel method by blending tetra-n-butoxytitanium tetramer (Nippon Soda, “B4”) and acetylacetone in a mixed solvent of n-butanol and isopropyl alcohol and mixing for 10 minutes using a stirrer. The coating liquid B as a precursor solution for forming a metal oxide layer (titanium oxide layer) was prepared.

(Production of Laminate 1)
As a substrate film, a 50 μm thick polyethylene terephthalate film ("Cosmo Shine (registered trademark) A4100" made by Toyobo Co., Ltd.) having an easy adhesion layer formed on one side is applied to the side opposite to the easy adhesion layer. The liquid A was applied and dried to form a thermoplastic resin layer (thickness 1.5 μm) made of an acrylic resin. Next, using a microgravure coater, the coating liquid B is coated on the surface of the thermoplastic resin layer, dried, and then irradiated with ultraviolet rays to perform sol-gel curing of the titanium oxide precursor, thereby forming the first layer. Metal oxide layer (titanium oxide layer) (thickness 40 nm) was formed. Next, an Al layer (100 nm in thickness) was formed by sputtering on the surface of the first metal oxide layer using a DC magnetron sputtering apparatus. Then, similarly to the first metal oxide layer, the second metal oxide layer (titanium oxide layer) (40 nm in thickness) was formed on the surface of the Al layer. The laminated body 1 was produced by the above.

(Production of radio wave transmission cover)
Prepare a sheet (2 mm in thickness) made of polycarbonate (PC) as a transparent resin material, prepare a black ABS sheet (2 mm in thickness) as a resin base, and place the base between the PC made sheet and the ABS made sheet The laminate 1 is disposed with the film side facing the ABS sheet, and polyvinyl butyral (PVB) sheet (thickness) as an adhesive layer between the PC sheet and the laminate 1 and between the ABS sheet and the laminate 1, respectively. 100 μm), and press forming was performed by a vacuum press at a pressure of 40 kN under a heat of 105 ° C. and a pressure time of 5 minutes. As described above, a radio wave transmission cover in which the laminate 1 was bonded between the PC sheet and the ABS sheet was produced.

(Example 2)
A laminate 2 was produced in the same manner as the production of the laminate 1 except that the thermoplastic resin layer was not formed. Next, a radio wave transmission cover was produced in the same manner as in Example 1 except that the laminate 2 was used instead of the laminate 1.

(Example 3)
A laminate 3 was produced in the same manner as the production of the laminate 1 except that the first and second metal oxide layers were not formed. Next, a radio wave transmission cover was produced in the same manner as in Example 1 except that the laminate 3 was used in place of the laminate 1.

(Comparative example 1)
A laminate 4 was produced in the same manner as the production of the laminate 1 except that the thermoplastic resin layer and the first and second metal oxide layers were not formed. Next, a radio wave transmission cover was produced in the same manner as in Example 1 except that the laminate 4 was used instead of the laminate 1.

(Examples 4 to 6, Comparative Example 2)
A radio wave transmission cover was produced in the same manner as in Examples 1 to 3 and Comparative Example 1 except that a sheet (thickness 2 mm) made of polymethyl methacrylate (PMMA) was used instead of the sheet made of PC as the transparent resin material.

(Examples 7 to 12 and Comparative Examples 3 to 4)
A radio wave transmission cover was produced in the same manner as in Examples 1 to 6 and Comparative Examples 1 and 2 except that the metal of the metal layer was changed from Al to In.

(Examples 13 to 16, Comparative Examples 5 to 8)
A radio wave transmission cover was produced in the same manner as in Examples 1 to 6 and Comparative Examples 1 and 2 except that the metal of the metal layer was changed from Al to Sn.

  The visible light reflectance and the radio wave permeability were measured and evaluated for the radio wave transmission cover obtained. The visible light reflectance is an index related to metallic gloss. For each metal, when the visible light reflectance is within a predetermined range, it can be determined that the metallic glossiness is good. In addition, photographs of the metal layer were taken for the following radio wave transmission cover to investigate the occurrence of cracks. In addition, the distance between cracks was measured from the photographed image.

(Visible light reflectance)
The transmission spectrum at a wavelength of 300 to 1000 nm was measured using a spectrophotometer (“UV 3100” manufactured by Shimadzu Corporation) in accordance with JIS A 5759, and the visible light reflectance was calculated.

(Radio wave permeability)
Radio wave attenuation factor of wavelength 76 to 77 GHz was measured and determined using an emblem evaluation system ("EES-01" manufactured by KEYCOM CO., LTD. "○, 3 dB or more" for radio wave attenuation factor obtained less than 3 dB The thing was made into "x".

(Photographing of metal layer)
The surface of the metal layer in the radio wave transmission cover was photographed with a laser microscope ("LEXT OLS 4000 (LEXT is a registered trademark") manufactured by Olympus Corporation. Examples 1 to 3 and Comparative Example 1 are shown in FIG. Comparative Example 3 is shown in FIG. 7, and Examples 13 to 15 and Comparative Example 5 are shown in FIG.
Example 1: Fig. 6 (a), Example 2: Fig. 6 (b), Example 3: Fig. 6 (c), Comparative Example 1: Fig. 6 (d)
Example 7: FIG. 7 (a), Example 8: FIG. 7 (b), Example 9: FIG. 7 (c), Comparative Example 3: FIG. 7 (d)
Example 13: FIG. 8 (a), Comparative Example 7: FIG. 8 (b), Example 14: FIG. 8 (c), Comparative Example 5: FIG. 8 (d)

(Measurement of distance between cracks)
The distance between cracks was measured at any five points in the photographed picture (1.25 mm × 1.25 mm range), and the average value was determined.

  From Table 1, since the thickness of the metal layer (Al layer) is sufficiently thick at 60 nm or more, the visible light reflectance is high in any of the examples and comparative examples, and the metallic glossiness is satisfied. However, from FIG. 6 (d), in Comparative Example 1, no crack was generated in the metal layer, and the radio wave permeability was not satisfactory. On the other hand, from FIG. 6 (a)-(c), the crack has generate | occur | produced in the metal layer in Examples 1-3, and the electromagnetic wave permeability is also satisfied.

  In the laminate 4 of Comparative Example 1, a thermoplastic resin layer formed from a coating solution containing a thermoplastic resin and a solvent having a softening temperature lower than the molding temperature, and a metal oxide layer formed by a sol-gel method In the laminates 1 to 3 of Examples 1 to 3, the thermoplastic resin layer and the metal oxide layer are contained. In the laminates 1 to 3, the metal oxide layer and the metal layer do not have cracks yet. It can be said that these layers function as a crack-inducing layer which induces cracks in the metal layer at the time of press forming, and the metal layer has cracks at the time of press forming.

  When Examples 1 to 3 are compared, it can be seen that the width of the crack is the largest in Example 1, the number of the cracks is the largest, and the radio wave transmittance is the most excellent. That is, it is understood that when the laminate includes both the thermoplastic resin layer and the metal oxide layer, it is easy to induce a crack particularly in the metal layer at the time of press molding, and in particular, it becomes excellent in radio wave transmittance. Moreover, when Example 2-3 is compared, the width | variety of a crack is larger in the direction of Example 2 than Example 3, and it turns out that there are many numbers of cracks and it is excellent in electromagnetic wave permeability more. That is, it can be seen that the thermoplastic resin layer has a higher effect of inducing a crack in the metal layer at the time of press molding than the metal oxide layer, and a high effect of improving the radio wave transmittance.

  Then, although not shown, the thermoplastic resin of the thermoplastic resin layer or the PVB of the adhesive layer intrudes into the cracks generated in the metal layer in Examples 1 to 3 by the cross-sectional observation of the radio wave transmission cover and fills them. I confirmed that it was.

  Examples 4 to 6 and Comparative Example 2 are the same as in Examples 1 to 3 and Comparative Example 1 except that the metal of the metal layer is the same, but the material of the transparent resin material is different. The surface photograph of the metal layer in the radio wave transmission cover is not shown, but the same results as in Examples 1 to 3 and Comparative Example 1 were obtained also in Examples 4 to 6 and Comparative Example 2.

  From Table 2, since the thickness of the metal layer (In layer) is sufficiently thick at 60 nm or more, the visible light reflectance is high in any of Examples and Comparative Examples, and the metallic glossiness is satisfied. However, from FIG. 7 (d), in Comparative Example 3, no crack was generated in the metal layer, and the radio wave permeability was not satisfactory. On the other hand, from FIG. 7 (a)-(c), the crack has generate | occur | produced in the metal layer in Examples 7-9, and the electromagnetic wave permeability is also satisfied.

  When Examples 7 to 9 are compared, it is understood that the width of the crack is the largest in Example 7, the number of the cracks is large, and the radio wave transmittance is the most excellent. That is, it is understood that when the laminate includes both the thermoplastic resin layer and the metal oxide layer, it is easy to induce a crack particularly in the metal layer at the time of press molding, and in particular, it becomes excellent in radio wave transmittance. Further, when Examples 8 to 9 are compared, it is understood that Example 9 has a larger width of crack than Example 8 and is more excellent in radio wave permeability. That is, it can be seen that the metal oxide layer has a higher effect of inducing a crack in the metal layer at the time of press molding than the thermoplastic resin layer, and a high effect of improving the radio wave transmittance.

  And although not shown in the drawings, in Examples 7 to 9, the thermoplastic resin of the thermoplastic resin layer and the PVB of the adhesive layer intrudes into the cracks generated in the metal layer by the cross-sectional observation of the radio wave transmission cover and the filling is carried out. I confirmed that it was.

  Examples 10 to 12 and Comparative Example 4 are the same as those of Examples 7 to 9 and Comparative Example 3 except that the metal of the metal layer is the same, but the material of the transparent resin material is different. The surface photograph of the metal layer in the radio wave transmission cover is not shown, but the results in Examples 10 to 12 and Comparative Example 4 are the same as in Examples 7 to 9 and Comparative Example 3.

  From Table 3, since the thickness of the metal layer (Sn layer) is sufficiently thick at 60 nm or more, the visible light reflectance is high in any of the examples and comparative examples, and the metallic glossiness is satisfied. However, according to FIGS. 8B and 8D, in Comparative Examples 5 and 7, no crack was generated in the metal layer, and the radio wave permeability was not satisfactory. On the other hand, from FIG. 8 (a), (c), in Example 13-14, the crack has generate | occur | produced in the metal layer and the electromagnetic wave permeability is also satisfied.

  Comparing Examples 13 to 14, it is understood that the width of the crack is the largest in Example 13, the number of the cracks is large, and the radio wave transmittance is the most excellent. That is, it is understood that when the laminate includes both the thermoplastic resin layer and the metal oxide layer, it is easy to induce a crack particularly in the metal layer at the time of press molding, and in particular, it becomes excellent in radio wave transmittance.

  Then, although not shown in the drawings, the thermoplastic resin of the thermoplastic resin layer and the PVB of the adhesive layer intrudes into the cracks generated in the metal layer in Examples 13 to 14 by the cross-sectional observation of the radio wave transmission cover. I confirmed that it was.

  Examples 15 to 16 and Comparative Examples 6 and 8 are the same as Examples 13 to 14 and Comparative Examples 5 and 7, although the metal of the metal layer is the same, but the material of the transparent resin material is different. The surface photograph of the metal layer in the radio wave transmission cover is not shown, but the same results as in Examples 13 to 14 and Comparative Examples 5 and 7 were obtained in Examples 15 to 16 and Comparative Examples 6 and 8.

  When the metal species of the metal layer are compared, cracking is likely to occur in the order of Al, In, and Sn. It can be said that Sn is the least susceptible to cracking. It is related to the Mohs hardness of metal and it can be said that In and Sn, which have relatively low Mohs hardness, are less susceptible to cracking. In the present invention, a crack is generated in the metal layer by heat and pressure at the time of press molding, even for In and Sn which are relatively unlikely to generate a crack, and a radio wave transmission cover having excellent metallic gloss and radio wave permeability is obtained.

  As mentioned above, although the Example of this invention was described, this invention is not limited at all to the said Example, A various change is possible within the range which does not deviate from the meaning of this invention.

DESCRIPTION OF REFERENCE NUMERALS 10 radio wave transmission cover 12 transparent resin material 14 decorative body 16 resin base material 18 radio wave transmission layer 18 'metal layer 20a, 20b metal oxide layer 22 thermoplastic resin layer 24 base film 26a, 26b adhesive layer 28 laminate 30, 40, 50 radio wave transmission cover 52 laminate

Claims (9)

A transparent resin material to be an exposed portion, a decorative body disposed inside the transparent resin material, a resin base material to be an attachment portion, and a metal disposed between the transparent resin material and the resin base material The radio wave transmission cover is provided with a radio wave transmission layer and the radio wave radar device is disposed on the back side.
Producing a laminate having a metal layer having a thickness of 60 nm or more and a crack-inducing layer which induces a crack in the metal layer;
Integrally forming the transparent resin material, the resin base material, and the laminate;
A method of manufacturing a radio wave transmission cover, wherein the radio wave transmission layer is formed by generating a crack in the metal layer by a temperature and pressure at the time of molding of the integral molding. A transparent resin material to be an exposed portion, a decorative body disposed inside the transparent resin material, a resin base material to be an attachment portion, and a metal disposed between the transparent resin material and the resin base material The radio wave transmission cover is provided with a radio wave transmission layer and the radio wave radar device is disposed on the back side.
Producing a laminate having a metal layer having a thickness of 60 nm or more and a crack-inducing layer which induces a crack in the metal layer;
And disposing the laminate between the transparent resin material and the resin base material to perform press molding,
A method of manufacturing a radio wave transmission cover, wherein the radio wave transmission layer is formed by generating a crack in the metal layer by a temperature and pressure at the time of molding of the press molding. A transparent resin material to be an exposed portion, a decorative body disposed inside the transparent resin material, a resin base material to be an attachment portion, and a metal disposed between the transparent resin material and the resin base material The radio wave transmission cover is provided with a radio wave transmission layer and the radio wave radar device is disposed on the back side.
Producing a laminate having a metal layer having a thickness of 60 nm or more with respect to one of the transparent resin material or the resin base, and a crack-inducing layer which induces a crack in the metal layer;
Performing the other injection molding of the transparent resin material or the resin base on the laminate;
A method of manufacturing a radio wave transmission cover, wherein the radio wave transmission layer is formed by generating a crack in the metal layer by a temperature and pressure at the time of molding of the injection molding.   The radio wave transmission cover according to any one of claims 1 to 3, wherein the material of the crack inducing layer is filled in the cracks generated in the metal layer by the temperature and pressure at the time of molding. Production method.   The crack-inducing layer is a thermoplastic resin layer formed from a coating liquid containing a thermoplastic resin and a solvent, and the thermoplastic resin is a thermoplastic resin having a softening temperature equal to or lower than the molding temperature. The manufacturing method of the electromagnetic wave transmission cover of any one of Claim 1 to 4 characterized by these.   The method for manufacturing a radio wave transmission cover according to any one of claims 1 to 5, wherein the crack inducing layer is a metal oxide layer formed by a sol-gel method.   7. The metal according to claim 1, wherein the metal of the metal layer is at least one of tin, tin alloy, aluminum, aluminum alloy, indium, indium alloy, chromium and chromium alloy. The manufacturing method of the electromagnetic wave transmission cover of 1 item.   The radio wave transmission cover according to any one of claims 1 to 7, wherein the resin of the transparent resin material is any one or two or more of a carbonate resin, an acrylic resin, and an olefin resin. Production method.   9. The resin according to any one of claims 1 to 8, wherein the resin of the resin base is any one or two or more of an acrylonitrile butadiene styrene resin and an acrylonitrile ethylene-propylene-diene styrene resin. The manufacturing method of the electromagnetic wave transmission cover as described in a term.