Electromagnetic wave shielding housing and its manufacturing method, resin housing coating sheet and laminated sheet

Abstract

The present invention provides a resin housing coating sheet, a laminated sheet, and an electromagnetic shield housing having the electromagnetic shield layer, which can improve wrinkle and breakage and form an electromagnetic shield layer with excellent electromagnetic shielding properties. [Solution] A resin housing covering sheet for forming the electromagnetic wave shielding layer 3 of an electromagnetic wave shielding housing 10 comprising a resin housing 1 and an electromagnetic wave shielding layer 3, wherein (i) when the sheet at room temperature is placed under a temperature of Tg to Tg + 40°C and measured at a tensile speed of 50 mm / min the elongation at break is 100 to 1500%, (ii) when the sheet at room temperature is placed under a temperature of Tg to Tg + 40°C and measured at a tensile speed of 1000 mm / min the elongation at break is 50 to 1200%, and (iii) when the sheet is measured at 23°C in a puncture test in accordance with JIS Z1707 the puncture strength per unit thickness is 5 to 150 N / mm.

Description

[Technical Field]

[0001] This disclosure relates to an electromagnetic shielding housing and a method for manufacturing the same. It also relates to a resin housing coating sheet and a laminated sheet. [Background technology]

[0002] The enclosures for electronic components used in vehicles and other applications require both lightness and electromagnetic shielding. For example, enclosures with an electromagnetic shielding layer coated onto a resin casing are attracting attention.

[0003] As a sheet for forming an electromagnetic wave shielding layer on a resin housing, for example, Patent Document 1 discloses an in-mold transfer molded film having electromagnetic wave shielding properties. The average molecular weight of the resin contained in this film is 5,000 or more and less than 10,000. Patent Document 2 also discloses a copper-polyimide laminate having rolled copper foil. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] International Publication No. 2023 / 243290 [Patent Document 2] Japanese Patent Publication No. 2013-146870 [Overview of the Initiative] [Problems that the invention aims to solve]

[0005] As a method of attaching a film to a three-dimensional shape, for example, the TOM molding (Three dimension Overlay Method: three-dimensional surface coating molding) method is known. Since the TOM molding method can be coated so as to follow the uneven shape and can impart various functions such as decorativeness and insulation, it is used for decorative applications such as automotive interior parts. Since the TOM molding method is suitable for coating three-dimensional shapes, it is also promising as a method of coating an electromagnetic shielding layer on a resin housing. However, it is difficult to simultaneously provide the film with electromagnetic shielding properties and stretchability, and coating defects such as wrinkles and breakage of the electromagnetic shielding layer are likely to occur. Coating defects not only cause poor appearance but also lead to quality deterioration and performance deterioration. That is, in the electromagnetic shielding layer, a decrease in shielding characteristics may occur. Due to the trend towards thinner, lighter, shorter, and smaller devices, these problems may become more serious. Further, if the formation position deviation of the electromagnetic shielding layer can be prevented, options such as coating only the area that requires coating become possible. Furthermore, it can be expected to significantly enhance versatility. In addition, although the problems in TOM molding were described above, the same problems may occur in vacuum molding, pressure air molding, vacuum pressure air molding, press molding, injection molding, etc.

[0006] The present disclosure has been made in view of the above problems, and an object thereof is to provide a resin housing coating sheet, a laminated sheet, an electromagnetic shielding housing having the electromagnetic shielding layer, and a manufacturing method thereof that can improve wrinkles and breakage and can form an electromagnetic shielding layer excellent in electromagnetic shielding properties.

Means for Solving the Problems

[0007] As a result of intensive studies by the present inventors, it has been found that the problems of the present disclosure can be solved in the following aspects, and the present disclosure has been completed. [1]: A resin housing coating sheet for forming the electromagnetic shielding layer of an electromagnetic shielding housing including a resin housing and an electromagnetic shielding layer that covers at least a part of the resin housing, (i) The resin housing coating sheet at room temperature is placed under a temperature of Tg to Tg + 40°C, and the elongation at break measured at a tensile speed of 50 mm / min at that temperature is 100 to 1500%. (ii) The resin housing coating sheet at room temperature is placed under a temperature of Tg to Tg + 40°C, and the elongation at break measured at a tensile speed of 1000 mm / min at that temperature is 50 to 1200%, and further, (iii) A resin housing coating sheet wherein the puncture strength α per unit thickness at 23°C, measured by a puncture test in accordance with JIS Z1707, is 5 to 150 N / mm. [2]: The resin housing covering sheet at room temperature is measured at any measurement temperature T between Tg and Tg+40°C. M Place it in the bottom and measure the temperature T M Young's modulus E measured at a tensile speed of 50 mm / min 50 And the measurement temperature T M Young's modulus E measured at a tensile speed of 1000 mm / min 1000 E ratio 1000 / E 50 A resin housing covering sheet as described in [1], wherein the ratio is 0.7 or higher. [3]: Contains a thermosetting resin and a curable compound, The curable compound is The resin housing coating sheet according to [1] contains a curable compound (c) having any of a hydroxyl group, a secondary amino group, or a tertiary amine group, and having two or more functional epoxy groups. [4]: A laminated sheet comprising a support layer and the resin housing covering sheet described in [1]. [5]: The laminated sheet according to [4], having a release layer between the support layer and the resin housing covering sheet. [6]: When the Tg of the support layer is Tg2 and the Tg of the resin housing covering sheet is Tg1, |Tg2-Tg1|≦100℃ The laminated sheet described in [4] is related to the following. [7]: An electromagnetic shielding housing comprising a resin housing and an electromagnetic shielding layer covering at least a part of the resin housing, The electromagnetic wave shielding housing is an electromagnetic wave shielding housing in which the electromagnetic wave shielding layer is a layer formed using a resin housing covering sheet as described in any of [1] to [3]. [8]: A method for manufacturing an electromagnetic shielding housing comprising a resin housing and an electromagnetic shielding layer covering at least a part of the resin housing, The process includes a coating step of forming the electromagnetic wave shielding layer using a resin housing covering sheet described in any of [1] to [3], A method for manufacturing an electromagnetic wave shielding housing, wherein the coating step is performed by one of the following methods: TOM molding, vacuum forming, pressure forming, vacuum pressure forming, press forming, or injection molding. [9]: A method for manufacturing an electromagnetic shielding housing comprising a resin housing and an electromagnetic shielding layer covering at least a part of the resin housing, A coating step of forming the electromagnetic wave shielding layer using a laminated sheet described in any of [4] to [6], The process includes removing layers other than the electromagnetic wave shielding layer from the laminated sheet after the coating process, A method for manufacturing an electromagnetic wave shielding housing, wherein the coating step is performed by one of the following methods: TOM molding, vacuum forming, pressure forming, vacuum pressure forming, press forming, or injection molding. [Effects of the Invention]

[0008] This disclosure provides excellent advantages, such as being able to improve wrinkles and breakage and form an electromagnetic shielding layer with excellent electromagnetic shielding properties, as well as an electromagnetic shielding housing having the electromagnetic shielding layer and a method for manufacturing the same. [Brief explanation of the drawing]

[0009] [Figure 1] A schematic cross-sectional view showing an example of an electromagnetic wave shielding housing according to the first embodiment. [Figure 2] A schematic cross-sectional view showing an example of a resin housing covering sheet according to the first embodiment. [Figure 3] A schematic cross-sectional view showing an example of the manufacturing process of the first embodiment. [Figure 4] A schematic cross-sectional view showing an example of the manufacturing process of the first embodiment. [Figure 5] A schematic cross-sectional view showing an example of the manufacturing process of the first embodiment. [Figure 6] A schematic cross-sectional view showing an example of a resin housing covering sheet according to the second embodiment. [Figure 7] A schematic cross-sectional view showing an example of a laminated sheet and manufacturing process according to the third embodiment. [Figure 8] A schematic cross-sectional view showing an example of a laminated sheet according to the fourth embodiment. [Figure 9] Figure 8 shows a cross-sectional view of the section between points IX and IX. [Figure 10] A schematic cross-sectional view showing an example of an electromagnetic shielding housing according to the fifth embodiment. [Figure 11] A schematic top view showing an example of a laminated sheet according to the fifth embodiment. [Modes for carrying out the invention]

[0010] The following describes an example of an embodiment to which this disclosure applies. Each embodiment can be combined in any way. The sizes and proportions of each component in the following figures are for illustrative purposes only and are not limiting. In this specification, the phrase "any number A to any number B" means that number A is the lower limit and number B is the upper limit within that range. Also, "sheet" and "film" are synonymous. Furthermore, the numerical values ​​specified in this specification are values ​​obtained by the methods disclosed in the embodiments or examples. In addition, each component may be used alone or in combination of two or more types unless otherwise specified.

[0011] 1. First Embodiment 1-1. Electromagnetic wave shielding enclosure Figure 1 shows an example of a schematic cross-sectional view of an electromagnetic shielding housing according to the first embodiment of this disclosure. An electromagnetic shielding housing refers to a housing in which a resin housing is covered with an electromagnetic shielding layer. As shown in the figure, the electromagnetic shielding housing 10 of the first embodiment comprises a resin housing 1 and an electromagnetic shielding layer 3 formed to cover at least a part of the resin housing 1.

[0012] The resin housing 1 can be any housing that can withstand the molding process for each application and can be arbitrarily selected. Because it can shield against electromagnetic waves, it is suitably applicable to resin housings that house or mount electronic components. The resin housing is used as part of an article or structure. Examples of resin housings include interior and exterior components for cars and exterior components for mobile devices.

[0013] The electromagnetic shielding layer 3 is provided across the entire surface from the top to the side of the resin housing 1. The electromagnetic shielding layer 3 is formed using the resin housing coating sheet of this disclosure (hereinafter also referred to as the coating sheet). The method for forming the electromagnetic shielding layer 3 from the coating sheet is not limited, but one of the following three-dimensional surface coating methods is preferred: TOM (Three-dimensional Overlay Method) molding, vacuum molding, pressure molding, vacuum pressure molding, press molding, or injection molding. Among these, the coating sheet is particularly suitable for TOM molding.

[0014] The electromagnetic shielding layer 3 is formed as a single or multi-layer structure. The electromagnetic shielding layer 3 contains, for example, a conductive material internally to shield electromagnetic waves. The electromagnetic shielding layer 3 may also include non-shielding layers with other functions as needed. Examples of non-shielding layers include insulating layers, thermal conductive layers, waterproof layers, shielding layers, coloring layers, flame retardant layers, hard coat layers, decorative layers, etc. In addition to being provided on the main surface of the resin housing 1, the electromagnetic shielding layer 3 may also be provided on the side surfaces of the resin housing 1 as shown in Figure 1.

[0015] In the example shown in Figure 1, the entire exposed surface of the main surface of the resin housing 1 is covered with the electromagnetic shielding layer 3. However, as in the electromagnetic shielding housing of the fifth embodiment described later, the electromagnetic shielding layer may be provided only partially.

[0016] 1-2. Resin housing covering sheet As described above, the resin housing coating sheet (the coating sheet) of this disclosure is a sheet for forming an electromagnetic shielding layer of an electromagnetic shielding housing. The coating sheet can physically protect the resin housing, shield from electromagnetic waves, and provide specific functions. A preferred example of the coating sheet is a conductive sheet having electromagnetic shielding properties. The coating sheet may further comprise a non-shielding sheet that does not have electromagnetic shielding properties. Examples of non-shielding sheets include insulating sheets having insulating properties, thermally conductive sheets that dissipate heat from the resin housing, shielding sheets that make the resin housing invisible or block light, moisture-proof sheets that protect the resin housing from moisture, decorative sheets with decoration, flame-retardant sheets with flame retardancy, protective sheets with hard coating properties, and sheets with any combination of these functions. Suitable examples of covering sheets having multiple functions include covering sheets that combine electromagnetic shielding, insulation, and thermal conductivity; covering sheets that combine electromagnetic shielding, insulation, and shielding; covering sheets that combine electromagnetic shielding and shielding; and covering sheets that combine electromagnetic shielding, insulation, and moisture resistance.

[0017] This coating sheet may be single-layered or multi-layered. In the case of a multi-layered configuration, multiple layers having the same function may be laminated, or layers with different functions may be laminated. For example, a coating sheet having a laminated structure of insulating layer / conductive layer, conductive layer / hard coat layer, conductive layer / waterproof layer, or thermal conductive layer / conductive layer can be exemplified.

[0018] Figure 2 shows a schematic cross-sectional view of an example of a resin housing covering sheet according to the first embodiment. As shown in the figure, the covering sheet 4 of the first embodiment has a laminated structure of an insulating layer 31 and a conductive layer 32. The insulating layer 31 is placed on the resin housing 1 side to protect the resin housing, and the conductive layer 32 provided on top of it provides electromagnetic shielding. The conductive layer 32 and the ground (not shown) of the electronic components housed in the resin housing 1 may be electrically connected by a pin (not shown) or the like. Alternatively, the conductive layer 32 may be placed on the resin housing 1 side and the insulating layer 31 may be placed on top of it. Or, the insulating layer 31 may be placed so as to sandwich the conductive layer 32 from above and below.

[0019] This coating sheet is a precursor material for the electromagnetic shielding layer and satisfies the following conditions (i) to (iii). In the case of multiple layers, each layer does not need to satisfy conditions (i) to (iii); it is sufficient that the coating sheet satisfies conditions (i) to (iii). (i) The resin housing coating sheet, at room temperature, is placed under a temperature of Tg to Tg + 40°C, and the elongation at break measured at a tensile speed of 50 mm / min at that temperature is 100 to 1500%. (ii) The resin housing coating sheet, at room temperature, is placed under conditions of Tg to Tg + 40°C, and the elongation at break measured at a tensile speed of 1000 mm / min at that temperature is 50 to 1200%. (iii) The resin housing coating sheet has a puncture strength α per unit thickness at 23°C measured by a puncture test in accordance with JIS Z1707, which is 5 to 150 N / mm. The Tg values ​​in this disclosure are those obtained by the method of this embodiment. Unless otherwise specified, Tg represents the glass transition temperature of the coating sheet. Furthermore, "Tg ~ Tg + 40°C" is a condition for indicating the characteristics of the resin housing coating sheet and does not limit the temperature when forming the electromagnetic shielding layer to this range. Also, the numerical values ​​in (i) to (iii) above are the values ​​obtained when the method and conditions described in the embodiment described later are used.

[0020] Breaking elongation refers to the permanent elongation of the coating sheet after it breaks during a tensile test. The value of breaking elongation was determined according to the method specified in JIS K7161:1994.

[0021] In this coating sheet, by setting the elongation at break of (i) above to 100% or more and the elongation at break of (ii) above to 50% or more, the elongation of the coating sheet is improved and tearing of the electromagnetic wave shielding layer can be suppressed. On the other hand, by setting the elongation at break of (i) above to 1500% or less and the elongation at break of (ii) above to 1200% or less, the occurrence of wrinkles can be suppressed. The control required to satisfy (i) and (ii) above in this coated sheet can be adjusted by the type of curable compound in the composition forming the coated sheet. Specifically, it can be adjusted by the number of functional groups and equivalent weight of the curable compound. It can also be adjusted by the content of the curable compound in the composition. Furthermore, it can be adjusted by the type, amount, and particle size of the filler. In addition, it can be adjusted by plasticizers, inert resins or oligomers that are not reactive themselves, and other flexibility modifiers that do not contribute to crosslinking.

[0022] Puncture strength is a value obtained from a puncture test in accordance with JIS Z1707 (23°C), and specifically, it is the strength at which the coating sheet breaks when a stainless steel rod (1 mm in diameter) is lowered perpendicularly to the coating sheet. Puncture strength per unit thickness is obtained by dividing the above puncture strength by the thickness of the resin housing coating sheet. By satisfying the above (iii) with a puncture strength per unit thickness, it is possible to effectively prevent the coating sheet from breaking at the edges of the resin housing and provide a coating sheet of superior quality.

[0023] The control required to satisfy (iii) above can be easily adjusted by the crosslinking density of the electromagnetic shielding layer. A preferred method is to adjust the type and equivalent amount of functional groups of the curable compound in the composition for forming the coating sheet. The curable compound preferably has a hydroxyl group, a secondary amino group, or a tertiary amine group, and more preferably has two or more functional epoxy groups. It can also be adjusted by the content of the curable compound in the composition. Furthermore, it can be adjusted by the type, amount, and particle size of the filler. Alternatively, it can be adjusted by the type of flexibility modifier that does not contribute to crosslinking, such as a plasticizer, an inert resin or oligomer that is not reactive in itself.

[0024] By satisfying the above (i) and (ii), the generation of wrinkles in the electromagnetic shielding layer that occurs during a vacuum process such as TOM molding can be effectively suppressed. Furthermore, by satisfying the above (i) and (ii) and further satisfying (iii), when heat and stress are applied to the coating sheet, or when the electromagnetic shielding housing is subjected to an impact, etc., the breakage of the sheet at the edge portion can be effectively prevented. Also, the displacement of the lamination position can be suppressed. As a result of these, the quality of the coating sheet can be significantly improved. Also, the appearance defect can be effectively improved. Therefore, according to this coating sheet, an electromagnetic shielding housing having an electromagnetic shielding layer of excellent quality can be provided.

[0025] The elongation at break of the above (i) is more preferably 150 to 1200%, and even more preferably 200 to 900% from the viewpoints of suppressing breakage and wrinkles of the electromagnetic shielding layer. By setting it to 100% or more, the strength of the coating sheet can be further increased, and breakage of the electromagnetic shielding layer can be more effectively prevented. Also, by setting it to 1500% or less, the generation of wrinkles can be suppressed. The elongation at break of the above (ii) is more preferably 100 to 1000%, and even more preferably 150 to 800% from the viewpoints of suppressing breakage and wrinkles of the electromagnetic shielding layer. The piercing strength α per unit film thickness of the above (iii) is more preferably 10 to 100 N / mm, and even more preferably 15 to 50 N / mm from the viewpoint of suppressing breakage of the electromagnetic shielding layer.

[0026] When this coating sheet contains a thermosetting resin, it becomes an electromagnetic shielding layer through a curing process by heating the resin housing coating sheet. The resin housing coating sheet may be provided with a release sheet on one or both sides for surface protection.

[0027] The Young's modulus of this coating sheet is obtained by putting the coating sheet at room temperature into an atmosphere at an arbitrary measurement temperature T M (where Tg ≤ T M ≤ Tg + 40°C) and measuring at a tensile speed of 50 mm / min or 1000 mm / min at that temperature. Hereinafter, the Young's modulus measured at a tensile speed of 50 mm / min is represented as E 50 and the Young's modulus measured at a tensile speed of 1000 mm / min is represented as E1000 This is expressed as follows. Also, with T as a variable, Young's modulus E measured at a certain temperature T is expressed as follows. 50 , E 1000 E 50(T) , E 1000(T) It is sometimes expressed as follows.

[0028] Young's modulus E of this covering sheet 50(Tg) The pressure is preferably 15 MPa or higher, and more preferably 40 MPa or higher. Also, E 50(Tg) The pressure is preferably 500 MPa or less, more preferably 400 MPa or less, and even more preferably 300 MPa or less. Furthermore, Young's modulus E 1000(Tg) The pressure is preferably 15 MPa or higher, and more preferably 40 MPa or higher. Also, E 1000(Tg) The pressure is preferably 300 MPa or less, more preferably 250 MPa or less, and even more preferably 200 MPa or less.

[0029] Furthermore, E of this covering sheet 50(Tg+40℃) The pressure is preferably 5 MPa or higher, and more preferably 10 MPa or higher. Also, E 50(Tg+40℃) The pressure is preferably 200 MPa or less, more preferably 150 MPa or less, and even more preferably 120 MPa or less. Furthermore, E 1000(Tg+40℃) The pressure is preferably 5 MPa or higher, and more preferably 10 MPa or higher. Also, E 50(Tg+40℃) The pressure is preferably 130 MPa or less, more preferably 100 MPa or less, and even more preferably 90 MPa or less.

[0030] Young's modulus E 50(Tg) and E 50(Tg+40℃) By setting the range to the above, it is possible to suppress the tearing of the electromagnetic shielding layer and improve its conformability to the adherend. Also, Young's modulus E 1000(Tg) and E 1000(Tg+40℃) By setting the range to the above, it is believed that the sheet will not flex during TOM molding, etc., and wrinkles can be suppressed.

[0031] The Young's modulus can be adjusted to the above range, for example, by adjusting the crosslinking density. Specifically, this can be done by adjusting the number of functional groups and equivalent amounts of the curable compound in the composition for forming the coating sheet. It can also be adjusted by the content of the curable compound in the composition. Furthermore, it can be adjusted by the type, amount, and particle size of the filler. It can also be adjusted by the type of flexibility modifier that does not contribute to crosslinking, such as plasticizers, inert resins or oligomers that are not reactive themselves.

[0032] Any measurement temperature T between Tg and Tg+40°C M Young's modulus E when measured at 1000 and Young's modulus E 50 E ratio 1000 / E 50 It is preferably 0.7 or higher, and more preferably 0.8 or higher. Also, ratio E 1000 / E 50 The upper limit of is preferably 1.4 or less, more preferably 1.3 or less, and particularly preferably 1.1 or less. 1000 / E 50 By setting the range as described above, it is possible to prevent sheet breakage in uneven areas of the resin housing, especially at the edges, when processed at temperatures Tg to Tg + 40°C, thereby more effectively preventing defects in appearance.

[0033] The Tg of this coating sheet is preferably in the range of 0 to 80°C, and more preferably in the range of 0 to 40°C, from the viewpoint of suppressing tearing and wrinkling of the electromagnetic wave shielding layer. If the coating sheet is multi-layered, it is preferable that the Tg of each layer be within the above range. In the case of multi-layered sheets, the Tg of the layer with the highest Tg is used as the reference.

[0034] The thickness of this coating sheet can be designed as appropriate depending on the application. For applications where thinness is required, the thickness of this coating sheet covering the top and sides of the resin housing is preferably in the range of 10 to 1000 μm, more preferably 15 to 500 μm, and even more preferably 20 to 250 μm.

[0035] When this covering sheet is used as an insulating layer, the surface resistance value is 1.0 × 107 It is preferable that the ratio be Ω / □ or greater, and 1.0 × 10 8 It is more preferable that the ratio be Ω / □ or greater, and 1.0 × 10 9 It is even more preferable that the resistance is Ω / □ or greater. When this coating sheet is used as a conductive layer, the surface resistance value is 1.0 × 10 2 It is preferable that the ratio is Ω / □ or less, and 1.0 × 10 1 It is more preferable that the ratio is Ω / □ or less, and even more preferable that it is 1.0Ω / □ or less.

[0036] This coating sheet contains a binder component. The binder component is the base component of the electromagnetic wave shielding layer. Examples of resins used for the binder component include thermosetting resins, photocurable resins, and mixtures thereof. Curable compounds that crosslink with these resins are also included in the binder component. Suitable thermosetting resins include self-crosslinking thermosetting resins as well as thermosetting resins that can react with curable compounds. These may be combined. A combination of a thermosetting resin and a curable compound is preferred as the binder resin. When using a curable compound, a thermosetting resin having reactive functional groups that can react with the curable compound is preferred. The binder resin can be used alone or in combination of two or more types.

[0037] Thermosetting resins have curable compounds or self-crosslinking reactive functional groups. Examples of functional groups include phenolic hydroxyl groups, acid anhydride groups, methoxymethyl groups, carboxyl groups, amino groups, epoxy groups, oxetanyl groups, oxazoline groups, oxazine groups, aziridine groups, thiol groups, isocyanate groups, blocked isocyanate groups, blocked carboxyl groups, and silanol groups.

[0038] Examples of thermosetting resins include polyurethane resins, polyurethane urea resins, phenoxy resins, acrylic resins, polyester resins, polyamide resins, epoxy resins, polystyrene resins, polycarbonate resins, polyamide-imide resins, polyesteramide resins, polyether ester resins, alkyd resins, polyimide resins, benzoxazine resins, amino resins, polylactic acid resins, oxazoline resins, silicone resins, and fluororesins. From the viewpoint of improving high-temperature resistance, epoxy resins, polyurethane resins, polyurethane urea resins, polycarbonate resins, phenoxy resins, polyimide resins, polyamide-imide resins, and polyamide resins are preferred among these. In particular, polyurethane resins, polyurethane urea resins, and polycarbonate resins are more preferred because they have excellent dispersibility of fillers (described later) and can increase puncture strength.

[0039] The acid value of the thermosetting resin is preferably 1 to 30 mg KOH / g from the viewpoint of improving adhesion to the resin housing. More preferably 1 to 20 mg KOH / g, and even more preferably 1 to 12 mg KOH / g.

[0040] The average molecular weight of the thermosetting resin is preferably 30,000 or more, and more preferably 50,000 or more, from the viewpoint of improving elongation at break. There is no particular upper limit to the average molecular weight, but from the viewpoint of improving resistance to moist heat, it is preferably 1,000,000 or less, and more preferably 500,000 or less.

[0041] The curable compound has a functional group that can react with the thermosetting resin. It is preferable that the compound has multiple functional groups. Examples of curable compounds include epoxy compounds, isocyanate compounds, polycarbodiimide compounds, aziridine compounds, acid anhydride group-containing compounds, amine compounds such as dicyandiamide compounds and aromatic diamine compounds, phenolic compounds such as phenol novolac resins, and organometallic compounds. The curable compound may be a resin or a low-molecular-weight compound. When a resin is used as the curable compound, the distinction between the thermosetting resin and the curable compound is made by using the one with the higher content as the thermosetting resin and the one with the lower content as the curable compound. The curable compound can be used alone or in combination of two or more.

[0042] From the viewpoint of effectively suppressing wrinkles and breakage of the electromagnetic wave shielding layer and improving adhesion to the resin housing, it is preferable to use a curable compound (c) (hereinafter also referred to as curable compound (c)) that has a hydroxyl group, a secondary amino group, or a tertiary amine group, and a bifunctional or greater epoxy group. By using curable compound (c), the curing reaction before the curing process can be accelerated to some extent, and breakage of the covering sheet during elongation in TOM molding and the like can be effectively prevented.

[0043] As a preferred example of curable compound (c), jER630 and 1001 manufactured by Mitsubishi Chemical Corporation are cited. Furthermore, among the group of bifunctional epoxy compounds exemplified later, compounds having a hydroxyl group, a secondary amino group, or a tertiary amine group are also suitably used as curable compounds.

[0044] In addition to the curable compound (c), a curable compound (d) having two or more functional epoxy groups may be further added. Compounds having a bifunctional epoxy group include bisphenol diglycidyl ethers such as bisphenol A diglycidyl ether, bisphenol F diglycidyl ether, bisphenol E diglycidyl ether, bisphenol Z diglycidyl ether, bisphenol S diglycidyl ether, bisphenol AD ​​diglycidyl ether, bisphenol acetophenone diglycidyl ether, bisphenol trimethylcyclohexane diglycidyl ether, bisphenol ful orange diglycidyl ether, tetramethylbisphenol A diglycidyl ether, tetramethylbisphenol F diglycidyl ether, tetra-t-butylbisphenol A diglycidyl ether, and tetramethylbisphenol S diglycidyl ether; biphenol diglycidyl ethers such as biphenol diglycidyl ether, tetramethylbiphenol diglycidyl ether, dimethylbiphenol diglycidyl ether, and tetra-t-butylbiphenol diglycidyl ether; and hydroquinone diglycidyl ether. Benzene diglycidyl ethers such as dihydroanthracene diglycidyl ether, methyl hydroquinone diglycidyl ether, dibutyl hydroquinone diglycidyl ether, resorcinol diglycidyl ether, and methyl resorcinol diglycidyl ether; aromatic diglycidyl ethers such as dihydroanthrahydroquinone diglycidyl ether, dihydroxydiphenyl ether diglycidyl ether, thiodiphenol diglycidyl ether, and dihydroxynaphthalene diglycidyl ether; Epoxy compounds obtained by adding hydrogen to the aromatic ring of diglycidyl ethers selected from the bisphenol-based diglycidyl ethers, biphenol-based diglycidyl ethers, benzenediol-based diglycidyl ethers, and aromatic diglycidyl ethers; epoxy resins produced from various carboxylic acids such as adipic acid, succinic acid, phthalic acid, tetrahydrophthalic acid, methylhexahydrophthalic acid, terephthalic acid, isophthalic acid, orthophthalic acid, biphenyldicarboxylic acid, and dimer acid, and epihalohydrins;Examples include (poly)alkylene glycol diglycidyl ethers consisting solely of chain structures, such as ethylene glycol diglycidyl ether, polyethylene glycol diglycidyl ether, propylene glycol diglycidyl ether, polypropylene glycol diglycidyl ether, 1,4-butanediol diglycidyl ether, polytetramethylene glycol diglycidyl ether, 1,5-pentanediol diglycidyl ether, polypentamethylene glycol diglycidyl ether, 1,6-hexanediol diglycidyl ether, polyhexamethylene glycol diglycidyl ether, 1,7-heptanediol diglycidyl ether, polyheptamethylene glycol diglycidyl ether, 1,8-octanediol diglycidyl ether, 1,10-decanediol diglycidyl ether, and 2,2-dimethyl-1,3-propanediol diglycidyl ether; and alkylene glycol diglycidyl ethers having cyclic structures, such as 1,4-cyclohexanedimethanol diglycidyl ether. Examples of commercially available products include DIC's EPICLON 830, 840, 850, 860, 1050, 2050, 3050, 4050, 7050, HM-091, 101, and Nagase ChemteX's Denacol EX-211, 212, 252, 711, 721.

[0045] From the viewpoint of adjusting the curing rates of semi-curing (B-stage curing) and full curing (C-stage curing), it is preferable to use a curable compound (e) that does not contain an epoxy group in combination with the curable compound (c). Suitable examples of curable compound (e) include combinations with one or more aziridine compounds, polycarbodiimide compounds, isocyanate compounds, imidazole compounds, and maleimide group-containing compounds.

[0046] In processes such as hot pressing, the epoxy groups of the epoxy compound can be thermally crosslinked with the carboxyl groups or hydroxyl groups of the thermosetting resin to obtain a crosslinked structure. Liquid epoxy compounds at room temperature (25°C) are also suitable as the epoxy compound. Specific examples include liquid bisphenol-type epoxy resins such as "R140P" (epoxy equivalent 188) from Mitsui Chemicals, "DER383" from Dow Chemical, and "Epicote #807" (epoxy equivalent 170) from Japan Epoxy Resin.

[0047] The content of the curable compound (c) is preferably 0.1 to 100 parts by mass, more preferably 1 to 50 parts by mass, and even more preferably 5 to 30 parts by mass, per 100 parts by mass of thermosetting resin. By setting the content within the above range, a strong cross-linked structure is formed in the electromagnetic shielding layer, while suppressing excessive hardening of the electromagnetic shielding layer and improving its ability to conform to uneven shapes. Furthermore, in TOM molding and the like, an electromagnetic shielding layer can be formed that effectively suppresses wrinkles and fractures.

[0048] Furthermore, the ratio of curable compound (d) to curable compound (c) is preferably 0 to 50, and more preferably 0.1 to 25. By setting the ratio within this range, a strong cross-linked structure is formed in the coating layer, while excessive hardening of the coating layer is suppressed, and the ability to conform to uneven shapes can be improved. Moreover, in TOM molding and the like, a coating layer can be formed that effectively suppresses wrinkles and fractures.

[0049] This coating sheet may further contain fillers. An insulating filler is used when insulation is required, a conductive filler is used when conductivity is required, and an electromagnetic wave absorbing filler is used when electromagnetic wave absorption is further required. The shape of the filler can be selected as appropriate. Examples include flake-shaped, needle-shaped, spherical, dendritic, and fibrous fillers. In particular, flake-shaped fillers are preferred because they have excellent electromagnetic wave shielding properties. Fillers of different shapes may also be used in combination. Preferred examples include combinations of flake-shaped fillers and spherical fillers, and flake-shaped fillers and dendritic fillers.

[0050] Average particle size D of flake-shaped conductive filler 50 The average particle size D of the dendritic conductive filler is preferably 1 to 100 μm, more preferably 2 to 80 μm, even more preferably 3 to 50 μm, and particularly preferably 5 to 20 μm. 50 Similarly, the preferred range is preferably 0.5 to 100 μm, more preferably 1.0 to 80 μm. Even more preferably 1.5 to 50 μm, and particularly preferably 2 to 20 μm.

[0051] From the viewpoint of suppressing tearing and wrinkling of the electromagnetic wave shielding layer, the filler content is preferably 30 to 80% by mass, and more preferably 40 to 70% by mass, based on 100% by mass of the covering sheet. In the case of a multi-layer structure, the total of all layers, calculated as (filler content of n layers × film thickness of n layers) / (total film thickness of the electromagnetic wave shielding layer) (where n is an integer of 2 or more), is preferably 30 to 80% by mass, and more preferably 40 to 70% by mass.

[0052] Examples of insulating fillers include non-metallic inorganic fillers such as silica, alumina, boron nitride, aluminum nitride, magnesium silicon nitride, silicon carbide, titania, glass, and ceramics. Insulating fillers can be used individually or in combination of two or more types.

[0053] Examples of conductive fillers include metal fillers, conductive ceramic fillers, and mixtures thereof. Examples of metal fillers include metal powders such as gold, silver, copper, and nickel; alloy powders such as solder; and core-shell type fillers such as silver-coated copper powder, gold-coated copper powder, silver-coated nickel powder, and gold-coated nickel powder. From the viewpoint of obtaining excellent conductive properties, conductive fillers containing silver are preferred. From the viewpoint of cost, silver-coated copper powder is particularly preferred.

[0054] Examples of electromagnetic wave absorbing fillers include iron, iron alloys such as Fe-Ni alloy, Fe-Co alloy, Fe-Cr alloy, Fe-Si alloy, Fe-Al alloy, Fe-Cr-Si alloy, Fe-Cr-Al alloy, and Fe-Si-Al alloy, ferrite materials such as Mg-Zn ferrite, Mn-Zn ferrite, Mn-Mg ferrite, Cu-Zn ferrite, Mg-Mn-Sr ferrite, and Ni-Zn ferrite, and carbon fillers. Examples of carbon fillers include acetylene black, Ketjen black, furnace black, carbon black, carbon fiber, fillers made of carbon nano-nanotubes, graphene fillers, graphite fillers, and carbon nanowalls.

[0055] This coating sheet may contain a flexibility modifier. The flexibility modifier can improve wrinkles and tears during the molding process of the coating sheet. Examples of flexibility modifiers include plasticizers and inert thermoplastic resins.

[0056] Examples of the aforementioned plasticizers include fatty acid esters, phthalate esters, aromatic polycarboxylic acid esters, and polyesters. Examples of fatty acid esters include trimellityl trioctyl (TOTM), manufactured by Mitsubishi Gas Chemical Trading Co., Ltd., butyl stearate, Unistar M-9676, Unistar M-2222SL, Unistar H-476, Unistar H-476D, Panacete 800B, Panacete 875, Panacete 810 (all manufactured by NOF Corporation), DBA, DIBA, DBS, DOA, DINA, DIDA, DOS, BXA, DOZ, DESU (all manufactured by Daihachi Chemical Co., Ltd.). Examples of phthalate esters include DMP, DEP, DBP, #10, BBP, DOP, DINP, DIDP (all manufactured by Daihachi Chemical Co., Ltd.), PL-200, DOIP (all manufactured by CG Ester Co., Ltd.), and Sansoizer DUP (manufactured by Shin Nippon Rika Co., Ltd.). Examples of aromatic polycarboxylic acid esters include TOTM (manufactured by Daihachi Chemical), Monosizer W-705 (manufactured by Daihachi Chemical), UL-80, and UL-100 (manufactured by ADEKA). Examples of polyesters include Polysizer TD-1720, Polysizer S-2002, Polysizer S-2010 (all manufactured by DIC), and BAA-15 (manufactured by Daihachi Chemical). Among these, DMP, DEP, DBP, DOP, DINP, DIDP, and TOTM are more preferred. The plasticizer may be used alone or in combination of two or more types.

[0057] Examples of the inert thermoplastic resin include polyolefin resins, vinyl resins, styrene-acrylic resins, diene resins, terpene resins, petroleum resins, cellulose resins, polyamide resins, polyurethane resins, polyester resins, polycarbonate resins, polyimide resins, liquid crystal polymers, and fluororesins. While not particularly limited, polyamide resins, polyurethane resins, polyester resins, polycarbonate resins, polyimide resins, liquid crystal polymers, and fluororesins are more preferred from the viewpoint of heat resistance.

[0058] Furthermore, the coating sheet may contain a tackifying resin to improve adhesion to the substrate. The tackifying resin is a component that supplementarily improves adhesive strength, has a weight-average molecular weight of less than 5,000, and is distinct from the thermoplastic resin and binder resin mentioned above. Examples of tackifying resins include rosin-based resins, terpene-based resins, alicyclic petroleum resins, and aromatic petroleum resins.

[0059] The coating sheet may further contain colorants, flame retardants, lubricants, anti-blocking agents, etc. Examples of flame retardants include halogen-containing flame retardants, phosphorus-containing flame retardants, nitrogen-containing flame retardants, and inorganic flame retardants. Examples of lubricants include fatty acid esters, hydrocarbon resins, paraffin, higher fatty acids, fatty acid amides, aliphatic alcohols, metal soaps, and modified silicones. Examples of anti-blocking agents include calcium carbonate, silica, polymethylsilsesquiosan, and aluminum silicate salts.

[0060] In the example shown in Figure 2, an example of a coating sheet consisting of a double layer of insulating layer 31 and conductive layer 32 is given. However, as mentioned above, it may be a single-layer coating sheet or a coating sheet consisting of double layers with the same function. Furthermore, the second layer may be patterned at any position on the first layer. For example, by using a coating sheet in which the insulating layer 31 is patterned at any position on the conductive layer 32, the conductive layer 32 can be formed over the entire exposed surface of one main surface of the resin housing 1, and an electromagnetic wave shielding layer having an insulating layer 31 can be formed where insulating protection is required. With this coating sheet, displacement of the coating position can be effectively prevented, so the design freedom of the coating sheet can be greatly increased.

[0061] 1-3. Method for manufacturing resin housing coating sheet The method for manufacturing the coating sheet is not particularly limited, but one example is to apply a composition obtained by dissolving a binder resin or other material that forms the electromagnetic wave shielding layer in a solvent to a release sheet. Examples of application methods include gravure coating, kiss coating, die coating, lip coating, comma coating, blade coating, roll coating, knife coating, spray coating, bar coating, spin coating, dip coating, or various printing methods. In the case of multi-layer coatings, known methods such as lamination or lamination via an adhesive can be applied.

[0062] 1-4. Applications of resin housing coating sheets This coating sheet is particularly suitable for coating resin housings, but it may also be used to coat other items to be coated. Electromagnetic shielding housings using this coating sheet are preferably installed in vehicles, liquid crystal displays, touch panels, and other electronic devices such as notebook PCs, mobile phones, smartphones, and tablet terminals.

[0063] 1-5. Manufacturing method of electromagnetic shielding enclosure An example of a TOM molding method for manufacturing an electromagnetic shielding housing using this coating sheet will be described. However, the manufacturing method of this electromagnetic shielding housing is not limited to the following. The electromagnetic shielding layer may be formed from this coating sheet by methods other than the TOM molding method (for example, vacuum forming, pressure forming, vacuum pressure forming, press forming, injection molding). For example, an electromagnetic shielding layer can be formed from this coating sheet by the method described in Japanese Patent No. 7193031.

[0064] The manufacturing method for this electromagnetic shielding housing involves a step of preparing a resin housing (step A), a step of preparing a resin housing covering sheet cut to a predetermined size (step B), and a covering step of forming an electromagnetic shielding layer using the covering sheet or a laminated sheet in which the covering sheets are laminated (step C), thereby obtaining an electromagnetic shielding housing covered and protected by an electromagnetic shielding layer formed from the resin housing covering sheet of this disclosure. Step C will be explained below using the schematic manufacturing process diagrams in Figures 3 to 5.

[0065] First, the resin housing 1 is placed on the stage 5 of the lower space 21 within the box 20, which has a lower space 21 and an upper space 22. Next, the covering sheet 4 is placed on the partition plate 6 so as to separate the upper space 22 and the lower space 21 (see Figure 3). Then, the inside of the box 20 is made into a vacuum state, and the covering sheet 4 is heated by the heating source 7 to around the Tg of the covering sheet 4 to soften it. Around Tg is, for example, a range of Tg ± 20°C. If the covering sheet 4 is multi-layered, the Tg of the layer with the highest Tg is used as the reference. Note that it is sufficient to fix the covering sheet 4, and instead of a partition plate, a fixing jig that holds the sheet may be used.

[0066] As the temperature of the covering sheet 4 approaches the ambient temperature (Tg) due to heating by the heating source 7, the flatness of the covering sheet 4 is lost and undulation appears (see Figure 4). Further heating reduces the undulation of the covering sheet 4, and the covering sheet 4 begins to bend due to its own weight, mainly in the center (see Figure 5). Heating the covering sheet 4 to this state effectively prevents wrinkles from forming in the electromagnetic shielding layer, thereby improving quality. In addition, heating the stage 5 on which the resin housing 1 is placed is preferable in order to improve the adhesion of the electromagnetic shielding layer to the resin housing 1. Heating has the effect of improving production efficiency during continuous production. The temperature of the stage 5 during heating is, for example, 50 to 120°C. From the viewpoint of improving continuous productivity, it is preferable that the temperature of the stage 5 during heating is in the range of Tg ± 20°C.

[0067] If necessary, the stage 5 installed in the lower space 21 is moved upward to bring a portion of the covering sheet 4 into contact with or close to the upper surface of the resin housing 1. Then, the surface of the covering sheet 4 is pressurized from the upper space 22 with air or compressed air. As a result, the covering sheet 4 follows the uneven surface of the resin housing 1. Next, the excess covering sheet is removed. If a thermosetting resin is used as the binder resin, a thermosetting treatment is performed; if a photocurable resin is used, a photocuring treatment is performed. Through these steps, an electromagnetic wave shielding housing 10 having an electromagnetic wave shielding layer 3 is obtained, as shown in Figure 1.

[0068] According to the above method, the covering sheet can be cut to match the covering area, and an electromagnetic shielding layer can be formed universally regardless of the shape or arrangement of the resin housing. Furthermore, since the electromagnetic shielding layer is formed by covering the entire surface with the covering sheet and then cutting off the excess electromagnetic shielding layer, there is the advantage that precise alignment between the covering sheet and the resin housing is unnecessary.

[0069] This coating sheet allows for the formation of a high-quality electromagnetic shielding layer even on lightweight, thin, and miniaturized resin housings by satisfying the above conditions (i) to (iii). The TOM molding method allows the coating sheet to be heated and softened, and then the pressure difference can be used to conform to three-dimensional uneven shapes, thereby significantly improving productivity.

[0070] 2. Second Embodiment A resin housing coating sheet according to the second embodiment will now be described. The resin housing coating sheet according to the second embodiment differs from that of the first embodiment in its layer structure, as will be described later, but the basic structure and manufacturing method are the same as those of the first embodiment. In the following figures, elements and components identical to those described above will be denoted by the same reference numerals as appropriate.

[0071] Figure 6 shows a schematic cross-sectional view of an example of a resin housing coating sheet according to the second embodiment. The coating sheet 4a consists of a first layer 41, a second layer 42, and a third layer 43, all of which are insulating layers, laminated in this order. The first layer 41, the second layer 42, and the third layer 43 may each be layers that have the same function as the first layer, or layers that have different functions. The preferred components, amounts, and layer characteristics of the first, second, and third layers are the same as in the first embodiment.

[0072] The first layer 41, positioned opposite the resin housing, is preferably designed to reduce warping and improve embedding. The second layer 42 is preferably designed to improve conformability to the three-dimensional shape of the resin housing during TOM molding and other processes, while also reducing warping. For this reason, it is preferable that the curable compounds of the first and second layers contain a liquid epoxy compound.

[0073] Liquid epoxy compounds are epoxy compounds that become liquid at 25°C. Preferred examples include jER(registered trademark (hereinafter omitted))YL980, jERYL983U, jER152, jER630, jERYX8000 (all trade names, manufactured by Mitsubishi Chemical Corporation), EPICLON(registered trademark), HP-4032 (both trade names, manufactured by DIC Corporation). Liquid epoxy compounds can be used individually or in combination of two or more.

[0074] The third layer 43 is preferably designed to primarily adjust the film thickness, optimize hardness, and enhance the durability of the coating sheet. It is preferable to include fillers to increase durability.

[0075] According to the second embodiment, by using a three-layer structure, the design freedom of each layer can be increased, thereby improving the functionality of the electromagnetic shielding layer. As a result, the adhesion and conformability of the joint surface between the covering sheet 4a and the resin housing 1 can be improved, and the occurrence of wrinkles in the electromagnetic shielding layer and fracture at the edges of the electromagnetic shielding layer can be effectively prevented.

[0076] In the second embodiment, an example of a covering sheet consisting of three layers was given, but it can be a single layer or multiple layers (two layers, four or more layers) without departing from the spirit of the present disclosure.

[0077] 3. Third Embodiment The manufacturing method of the electromagnetic shielding housing according to the third embodiment differs from the manufacturing method of the first embodiment in that it uses a laminated sheet having the covering sheet, but the basic structure and basic manufacturing method of the electromagnetic shielding housing are the same as those of the first embodiment.

[0078] Figure 7 shows a schematic diagram illustrating an example of the manufacturing process for an electromagnetic shielding enclosure according to the third embodiment. In the first embodiment, the covering sheet 4 was placed on the partition plate 6, but in the third embodiment, a laminated sheet 50 is placed on the partition plate 6. The laminated sheet 50 has a support layer 8 and a covering sheet 4 formed on the support layer 8. The size of the covering sheet 4 is set to the size necessary to form the electromagnetic shielding layer. This method makes it possible to omit the step of cutting off unnecessary parts after the electromagnetic shielding layer has been formed.

[0079] The method for manufacturing the laminated sheet 50 is not limited, but a simple method is to attach the covering sheet 4 to a desired position on the support layer 8. A preferred method is to heat and temporarily attach the covering sheet 4 to the support layer 8. The support layer 8 has the role of fixing during the manufacturing process (in this example, by placing it on the partition plate 6 and fixing it) and supporting the covering sheet. The support layer can also be called a peel-off layer since it is peeled off after the electromagnetic wave shielding layer is formed. The laminated sheet 50 is covered on the resin housing 1 in the same manner as in the first embodiment to form the electromagnetic wave shielding layer 3, and then the support layer 8 is peeled off to obtain an electromagnetic wave shielding housing.

[0080] The support layer 8 is not particularly limited as long as it has the above-mentioned functions. Preferred examples include polyvinyl chloride (PVC), polyolefin, etc. The thickness of the support layer 8 is preferably 5 to 500 μm, and more preferably 10 to 250 μm, from the viewpoint of improving conformability to the adherend. The Tg of the support layer 8 is preferably 30 to 90°C, and more preferably 40 to 80°C, from the viewpoint of improving conformability to the adherend. The Tg1 of the covering sheet 4 and the Tg2 of the support layer 8 are |Tg2-Tg1|≦100℃ It is preferable that the relationship is as follows. By setting it within this range, the ability to conform to the uneven shape of the resin housing can be more effectively improved. |Tg2-Tg1|≦80℃ The Tg2 of the support layer can be adjusted depending on the type of resin and its manufacturing conditions. It is preferable to set the temperature inside box 20 to within ±20°C of the higher of Tg1 and Tg2.

[0081] Alignment of the resin housing and the covering sheet can be performed using any known method without limitation. For example, precise alignment can be achieved by aligning the marks on the support layer with the marks on the stage.

[0082] According to the covering sheet of the third embodiment, there is no need to use a covering sheet 4 that is sized to fit on the partition plate 6 of the box 20, thus eliminating the loss of the covering sheet 4 and reducing costs. Furthermore, since the covering sheet 4a can be adjusted to the desired size according to the size of the resin housing, its versatility can be greatly increased. In addition, since the covering sheet 4 can be supported by the support layer 8, there is an advantage in that it is easier to achieve a thin electromagnetic shielding layer.

[0083] 4. Fourth Embodiment The laminated sheet according to the fourth embodiment differs from the laminated sheet of the third embodiment, which does not have a release layer 9, in that it has a release layer 9 between the support layer 8 and the covering sheet 4a. Figure 8 shows a schematic plan view of an example of the laminated sheet according to the fourth embodiment, and Figure 9 shows a cross-sectional view of the section IX-IX in Figure 8. As shown in these figures, the support layer 8, release layer 9, and covering sheet 4a are laminated in this order. The area of ​​each layer is support layer 8 > release layer 9 > covering sheet 4a, and in a top view, the frame area of ​​the release layer 9 is outside the covering sheet 4a, and the frame area of ​​the support layer 8 is outside the release layer 9. The support layer 8 is sized to be placed on the partition plate 6, and the covering sheet 4a is sized to be optimal for forming the electromagnetic shielding layer. The release layer 9 has an area that extends from the edge of the covering sheet 4a, taking into consideration ease of peeling after the formation of the electromagnetic shielding layer. Preferred examples of the release layer 9 include polypropylene (PP) and polyethylene (PE).

[0084] The thickness of the release layer 9 is, for example, about 5 to 1000 μm. From the viewpoint of improving conformability to the adherend, 5 to 500 μm is preferred, and 10 to 250 μm is more preferred. The Tg of the release layer 9 is preferably -50 to 50°C, and more preferably -20 to 20°C.

[0085] According to the fourth embodiment, by using the release layer 9, adhesion between the support layer 8 and the covering sheet 4a can be effectively prevented, damage to the electromagnetic shielding layer 3 can be prevented, and the manufacturing yield can be increased. Furthermore, the range of materials for the support layer 8 can be significantly increased. In addition, lamination positional misalignment can be effectively improved.

[0086] 5. Fifth Embodiment The fifth embodiment differs from the first embodiment in that the electromagnetic shielding layer is provided on the entire surface of one main surface of the electromagnetic shielding housing, in that the electromagnetic shielding layer is provided on a part of one main surface of the electromagnetic shielding housing. Figure 10 shows a schematic cross-sectional view of an example of an electromagnetic shielding housing according to the fifth embodiment. The electromagnetic shielding layer 3a provided on the electromagnetic shielding housing 11 covers a portion of the exposed surface of one main surface of the resin housing 1. The partially covered electromagnetic shielding layer 3a can be formed, for example, using a laminated sheet according to the third or fourth embodiment.

[0087] According to the electromagnetic shielding housing of the fifth embodiment, an electromagnetic shielding layer can be easily formed at the location where protection is needed. Furthermore, by using the laminated sheet of the third or fourth embodiment, positional displacement can be effectively prevented. In addition, as shown in Figure 11, multiple covering sheets 4 may be laminated on the support layer 8. According to this method, multiple electromagnetic shielding layers 3 having the necessary functions can be formed at desired locations all at once, according to the functions required of the electromagnetic shielding housing. [Examples]

[0088] The present disclosure will be described in detail below with reference to examples and comparative examples, but the present disclosure is not limited to the following examples. Note that the following "parts" and "%" are values ​​based on "parts by mass" and "mass%", respectively.

[0089] A. Covering sheet The raw materials used in the examples are listed below. A-1.Thermosetting resin [Synthesis of thermosetting resin r1] In a glass flask equipped with a stirrer, thermometer, reflux condenser, nitrogen inlet tube, and vacuum equipment, 166 parts terephthalic acid, 146 parts adipic acid, 212 parts 3-methyl-1,5-pentanediol, and 25 parts ethylene glycol were charged and stirred while passing nitrogen gas through. The mixture was gradually heated under atmospheric pressure and reacted at 200-230°C for approximately 8 hours to obtain a liquid with an acid value of 43 mg KOH / g. Next, 0.01 parts tetra-n-butoxytitanium was charged, and after purging with nitrogen, the mixture was stirred at 180°C for 30 minutes under a sealed condition. Then, the mixture was reacted at 230°C and 5 mmHg for 2 hours to obtain a polyester diol with an acid value of 1.1 mg KOH / g, a hydroxyl value of 114.2 mg KOH / g, and a molecular weight of 982. The acid value and hydroxyl value were determined by weighing the thermosetting resin and measuring them using a GT-200 automatic titrator manufactured by Mitsubishi Chemical Analytical Corporation, in accordance with the potentiometric titration method specified in JIS K0070, and then converting them to solid content.

[0090] Next, 734 parts of the polyester diol, 23.9 parts of dimethylolpropionic acid, 219 parts of toluene diisocyanate, and 242 parts of toluene were charged into a reaction vessel equipped with a stirrer, thermometer, reflux condenser, dropping device, and nitrogen inlet tube, and the mixture was reacted at 50°C under a nitrogen atmosphere for 8 hours. To this, 1200 parts of toluene was added to obtain a urethane prepolymer solution having isocyanate groups at the ends.

[0091] Next, the obtained urethane prepolymer solution was heated to 70°C, and while maintaining this temperature, a solution of 20.0 parts 1,3-diaminopropane, 3.1 parts benzylamine, 600 parts 2-pronol, and 961 parts toluene was added dropwise over 1 hour. After the dropwise addition was complete, the reaction was continued at 70°C for a further 6 hours to obtain a polyurethane resin with a molecular weight (Mw) of 130,000, an acid value of 10 mgKOH / g, a Tg of 20°C, and a solids content of 25%.

[0092] [Synthesis of thermosetting resin r2] A polyurethane resin with a molecular weight (Mw) of 250,000, an acid value of 11 mgKOH / g, a Tg of 20°C, and a solids content of 18% was obtained in the same manner as the synthesis of thermosetting resin r1.

[0093] [Synthesis of thermosetting resin r3] A polyurethane resin with a molecular weight (Mw) of 80,000, an acid value of 10 mgKOH / g, a Tg of 20°C, and a solids content of 40% was obtained in the same manner as the synthesis of thermosetting resin r1.

[0094] [Synthesis of thermosetting resin r4] A polyurethane resin with a molecular weight (Mw) of 20,000, an acid value of 12 mgKOH / g, a Tg of 20°C, and a solids content of 55% was obtained in the same manner as the synthesis of thermosetting resin r1.

[0095] A-2. Curing compound The following curable compounds (c1) and (c2) were used as curable compound (c). Curable compound (c1): Trifunctional epoxy resin "jER630", containing tertiary amine, manufactured by Mitsubishi Chemical Corporation. Curable compound (c2): Bifunctional epoxy resin "jER1001", containing hydroxyl groups, manufactured by Mitsubishi Chemical Corporation. Furthermore, the following compounds were used as curable compounds (d) and (e), respectively. Curable compound (d): Polyfunctional epoxy resin "jER175S70", manufactured by Mitsubishi Chemical Corporation. Curable compound (e): Aziridine compound "Chemitite PZ-33", manufactured by Nippon Shokubai Co., Ltd.

[0096] A-3. Filler Filler f1: Scale-like silver filler (D 50 (4.0~7.0μm) Manufactured by Fukuda Metal Industries Co., Ltd. Filler f2: Dendritic silver-coated copper filler (scale silver filler D) 50 (=10.4μm) Manufactured by DOWA Corporation

[0097] B. Support layer Support layer X1: Polyvinyl chloride sheet made from polyvinyl chloride powder (manufactured by Zeon Corporation) by melt rolling, Tg: 76℃ Support layer X2: Polyvinyl chloride sheet prepared by solvent method using polyvinyl chloride powder (manufactured by Zeon Corporation), Tg: 54℃ Support layer X3: Olefin sheet made from cycloolefin polymer ZEONOR (manufactured by Zeon Corporation) by melt extrusion, Tg: 125℃

[0098] C. Release layer Release layer Y1: Co-extrusion protective film Eltec MX 157N3U, manufactured by Nippon Matai Co., Ltd., Tg: -1℃

[0099] D.Measurement method D-1. Glass transition temperature Tg The Tg of each example and comparative example sample (resin housing coating sheet), release layer, and support layer was measured using a dynamic viscoelasticity analyzer DVA-200 (manufactured by IT Measurement Control Co., Ltd.) in accordance with JIS K7198. For the measurement, the resin housing coating sheet of each example was cut to 0.5 cm x 3 cm and the release film was peeled off. The deformation mode was tensile, and Tg was defined as the temperature at which the main dispersion peak of the loss loss tangent (tanδ) appeared, measured at a strain of 0.08%, a frequency of 10 Hz, and a heating rate of 10 °C / min.

[0100] D-2. Elongation at break and Young's modulus The resin housing coating sheets with release films obtained from each example and comparative example using the method described later were cut to a size of 20 mm wide x 60 mm long. Next, the release film was peeled off to obtain a measurement sample (resin housing coating sheet) consisting of the coating sheet. Each measurement sample (coating sheet) was placed from room temperature to a temperature of Tg + 40°C (in air, 50% RH), and one minute later, a tensile test was performed at the same temperature under conditions of a tensile speed of 50 mm / min and relative humidity of 50% using a small benchtop testing machine EZ-TEST (manufactured by Shimadzu Corporation) with an effective tensile size of 20 x 23 mm, and the elongation at fracture at a tensile speed of 50 mm / min was determined. In addition, the tangent to the linear region before the yield point in the stress-strain curve during the tensile test was determined, and the Young's modulus E was calculated. 50(Tg+40℃) Similarly, each sample (coated sheet) was placed from room temperature to Tg temperature (in air, 50% RH), and the elongation at break and Young's modulus E were measured using the same method. 50(Tg) We measured it. Similarly, the covering sheet was placed in an atmosphere of Tg + 40°C from room temperature, and after 1 minute, a tensile test was performed at the same temperature with a tensile speed of 1000 mm / min and relative humidity of 50%, using an effective tensile size of 20 × 23 mm, and the elongation at fracture at a tensile speed of 1000 mm / min was determined. Furthermore, using the same method with the above apparatus, the Young's modulus E was determined at a test speed of 1000 mm / min. 1000(Tg+40℃) The following was determined. Similarly, each sample (coated sheet) was placed from room temperature to Tg temperature (in air, 50% RH), and the elongation at break and Young's modulus E were determined using the same method at a tensile speed of 1000 mm / min. 1000(Tg) We measured it.

[0101] D-3.Piercing strength Resin housing coating sheets (100 mm x 100 mm) were prepared for each example and comparative example, and the puncture strength per unit thickness at 23°C was determined by a puncture test in accordance with JIS Z1707. Specifically, the sheets were placed in a sample mounting jig with an 80 mm diameter opening and set up in a TE-1003 low-temperature / high-temperature bath peel tester type II (manufactured by Tester Sangyo Co., Ltd.) equipped with a 1 mm diameter stainless steel rod (17 mm length) as a measurement probe. Under the condition of a measurement temperature of 23°C, the probe was inserted into the resin housing coating sheet at a speed of 100 mm / min, and the strength at the time of fracture was recorded as the puncture strength. The puncture strength α per unit thickness was calculated by dividing the obtained puncture strength value by the thickness of the resin housing coating sheet.

[0102] D-4. Film Thickness The thickness of the electromagnetic shielding layer in the electromagnetic shielding enclosure was determined by cross-sectioning using a polishing method, and the film thickness at the thickest point on the top surface of the enclosure was measured using a laser microscope. Five cross-sectional samples from different electromagnetic shielding enclosures were measured similarly, and the average value was used as the thickness.

[0103] E. Fabrication of resin housing covering sheets and laminated sheets [Example 1] 100 parts of thermosetting resin r1 (solids), 8 parts of jER630, 2 parts of jER175S70, 0.5 parts of PZ-33, 154 parts of filler f1, and 31 parts of filler f2 were placed in a container, toluene was added to achieve a non-volatile content concentration of 33% by mass, and the mixture was stirred with a disperser for 10 minutes to obtain the composition. This composition was coated onto a release film (release-treated polyethylene terephthalate film, 50 μm thick) using a doctor blade to achieve a dry thickness of 30 μm. The release film-coated resin housing sheet of Example 1 was then dried at 100°C for 2 minutes. After cutting the obtained resin housing coating sheet with release film into 100 mm squares, the release film was peeled off, and a support layer X1 (300 mm square) with release function was laminated onto the surface where the release film had been laminated, thereby obtaining the laminated sheet (support layer X1 / electromagnetic wave shielding layer) according to Example 1. The resin housing coating sheet was positioned in the center of the support layer X1 in a plan view.

[0104] [Examples 2-18, Comparative Examples 1-4] Laminated sheets (support layer X1 / electromagnetic shielding layer) for Examples 2-18 and Comparative Examples 1-4 were obtained by the same method except for changing the proportions of the ingredients shown in Tables 1-4.

[0105] [Examples 19, 22] Except for using a laminate of support layer X2 or X3 instead of support layer X1, the laminated sheet of Example 19 (support layer X2 / electromagnetic shielding layer) and the laminated sheet of Example 22 (support layer X3 / electromagnetic shielding layer) were obtained by the same procedure as in Example 1.

[0106] [Example 20] Except for laminating a release layer Y1 between the support layer X2 and the electromagnetic shielding layer, the laminated sheet of Example 20 (support layer X2 / release layer Y1 / electromagnetic shielding layer) was obtained by the same procedure as in Example 19.

[0107] [Example 21] The laminated sheet of Example 21 (support layer X2 / release layer Y1 / electromagnetic shielding layer) was obtained by the same procedure as in Example 20, except that the composition was coated to a dry thickness of 50 μm.

[0108] F. Preparation of the resin enclosure A resin casing made of polycarbonate (manufactured by Takiron CI Co., Ltd.) was prepared with dimensions of D:30mm, W:50mm, H:20mm, and corner radius R:2mm. The thickness of the resin casing was 1mm.

[0109] G. Rating G-1.TOM aptitude For each example and comparative example, the sample was positioned so that the resin housing coating sheet portion (10 cm x 10 cm) of the laminated sheet overlapped with the center of the test resin housing. Overlay molding was performed using a TOM molding machine (manufactured by Fuse Vacuum Co., Ltd.) at a set temperature Tg + 40°C. After peeling off the release layer (support layer, or support layer + release layer), post-baking was performed at 130°C for 120 minutes to obtain an electromagnetic shield housing. The appearance of the obtained electromagnetic shield housing was evaluated for wrinkles and tears according to the following criteria.

[0110] G-2.Wrinkles The number and length of wrinkles present in the resin housing coating sheet on the electromagnetic wave shielding housing were measured and evaluated according to the following criteria. +++: The number of wrinkles is 0 to 2, and the length of each wrinkle is less than 5 mm. ++: The number of wrinkles is between 3 and 10, and the length of each wrinkle is less than 3 mm. +: The number of wrinkles is between 3 and 10, and the length of each wrinkle is between 3mm and 5mm. (Practical level) NG: The number of wrinkles is 11 or more, or the length of each wrinkle is 5 mm or longer.

[0111] G-3. Torn The number of tears in the resin covering sheet on the electromagnetic shielding housing was counted and evaluated according to the following criteria. +++: The number of tears is between 0 and 5. ++: The number of tears is between 6 and 10. +: The number of tears is between 11 and 15. (Practical level) NG: The number of tears is 16 or more.

[0112] G-4. Mold releasability The laminated sheets of each example and comparative example were cut to 25 mm x 100 mm, and a 75 μm thick polyimide film ("Kapton 300H," manufactured by Toray DuPont) was placed on top of the resin housing coating sheet and laminated at 80°C. Next, the resulting samples were peeled from the release layer to the resin housing coating sheet using a tensile testing machine at a peeling speed of 50 mm / min, and the peeling force was measured. The results were evaluated according to the following criteria. +++: Can be peeled off at the interface between the release layer and the resin housing coating sheet, and the peeling force is 2 N / cm or less. ++: Can be peeled off at the interface between the release layer and the resin housing coating sheet, and the peeling force is greater than 2 N / cm and less than or equal to 3 N / cm. +: Can be peeled off at the interface between the release layer and the resin housing coating sheet, and the peeling force is greater than 3 N / cm. (Practical level) NG: The release layer cannot be peeled off at the interface between the release layer and the resin housing coating sheet.

[0113] G-5. Adhesion Using a cross-cut guide in accordance with JIS K5400, 100 grid lines with a 1 mm spacing were created on the resin housing coating sheet on the resin housing. Then, adhesive tape was firmly pressed onto the grid lines, and the end of the tape was peeled off in one swift motion at a 45° angle. The condition of the grid lines was then judged according to the following criteria. +++: Peeling rate less than 5%. ++: The resin casing sheet is partially peeling along the cut line. Peeling rate is between 5% and 10%. +: The resin casing sheet is partially peeling along the cut line. Peeling rate is between 10% and 15%. NG: The resin casing sheet is partially or completely peeling along the cut line. A peeling rate of 15% or more makes it unusable.

[0114] G-6. Electromagnetic shielding properties The laminated sheets of each example and comparative example were cut to 120 mm x 120 mm, and a 25 μm thick polyimide film ("Kapton 100H" manufactured by Toray DuPont) was placed on the electromagnetic shield side and laminated at 80°C. After peeling off the release layer (support layer, or support layer + release layer), post-bake was performed at 130°C for 120 minutes, and the electromagnetic shielding performance was evaluated using the KEC method with an electric field measurement jig at a frequency of 500 MHz, and the electromagnetic shielding performance was judged according to the following criteria. +++: 60dB or higher. ++: 50dB or higher, less than 60dB. +: 40dB or higher, less than 50dB. NG: Below 40dB. Not practical.

[0115] [Table 1]

[0116] [Table 2]

[0117] [Table 3]

[0118] [Table 4]

[0119] The coated sheets with a breaking elongation of less than 100% in (i) and / or less than 50% in (ii) were found to have problems with tearing during processing, as shown in Comparative Examples 1, 3, and 4. Furthermore, the coated sheets with a breaking elongation exceeding 1500% in (i) and exceeding 1000% in (ii) were found to have problems with wrinkles during processing, as shown in Comparative Example 2. In contrast, the coated sheets of this embodiment, which satisfy all of the above conditions (i) to (iii), were found to be excellent in suppressing wrinkles and tears during processing, and also excellent in release properties, adhesion, and electromagnetic shielding properties.

[0120] Also, Young's modulus E 1000 and Young's modulus E 50 Ratio E 1000 / E 50 For coated sheets with a ratio of less than 0.7, it was confirmed that there were issues with wrinkles during processing, as shown in Comparative Examples 1 and 3. On the other hand, in the range of Tg to Tg+40℃, ratio E 1000 / E 50 In this embodiment, where the ratio E was 0.7 or higher, it exhibited excellent suppression of wrinkles and tears during processing, as well as excellent release properties, adhesion, and electromagnetic shielding properties. Furthermore, the ratio E 1000 / E 50 Examples 1-11, 13-17, and 19-23, which satisfy the ratio of 0.8 or higher, all received evaluations of ++ or higher for wrinkle and tear suppression, confirming their particularly excellent performance. Example 24 had a ratio of E 1000 / E 50 Although the |Tg2-Tg1| value was 0.8 or higher, the |Tg2-Tg1| value exceeded 100°C, resulting in inferior wrinkle and tear suppression and mold release properties compared to the above example where |Tg2-Tg1| ≤ 100°C was satisfied. [Explanation of symbols]

[0121] 1. Resin housing 3. Electromagnetic shielding layer 4. Covering sheet 5 stages 6 partition plates 7 Heating source 8 Support layer 9 Release layer 10, 11 Electromagnetic wave shielding enclosure 20 boxes 21 Lower space 22 Upper space 31 Insulating layer 32 Conductive layer 41 First layer 42 Second layer 43 Third layer 50 Laminated Sheets

Claims

1. A resin housing covering sheet for forming the electromagnetic shielding layer of an electromagnetic shielding housing comprising a resin housing and an electromagnetic shielding layer covering at least a portion of the resin housing, (i) The resin housing coating sheet at room temperature is placed under a temperature of Tg to Tg + 40°C, and the elongation at break measured at a tensile speed of 50 mm / min at that temperature is 100 to 1500%. (ii) The resin housing coating sheet at room temperature is placed under a temperature range of Tg to Tg + 40°C, and the elongation at break measured at a tensile speed of 1000 mm / min at that temperature is 50 to 1200%, and further, (iii) A resin housing coating sheet wherein the puncture strength α per unit thickness at 23°C, measured by a puncture test in accordance with JIS Z1707, is 5 to 150 N / mm.

2. The resin housing coating sheet at room temperature is subjected to any measurement temperature T between Tg and Tg + 40°C. Ｍ Place it in the bottom and measure the temperature T Ｍ Young's modulus E measured at a tensile speed of 50 mm / min ５０ And the measurement temperature T Ｍ Young's modulus E measured at a tensile speed of 1000 mm / min １０００ E １０００ / E ５０ The resin housing covering sheet according to claim 1, wherein the ratio is 0.7 or higher.

3. It contains a thermosetting resin and a curable compound. The curable compound is The resin housing coating sheet according to claim 1, comprising a curable compound (c) having any of a hydroxyl group, a secondary amino group, or a tertiary amine group, and having two or more functional epoxy groups.

4. A laminated sheet comprising a support layer and the resin housing covering sheet described in claim 1.

5. The laminated sheet according to claim 4, wherein a release layer is provided between the support layer and the resin housing covering sheet.

6. Let the Tg of the support layer be Tg ２ and when the Tg of the resin housing coating sheet is Tg １ then |Tg ２ -Tg １ |≦100℃ The laminated sheet according to claim 4, which is in a relationship with the other.

7. An electromagnetic wave shielding housing comprising a resin housing and an electromagnetic wave shielding layer covering at least a portion of the resin housing, An electromagnetic wave shielding housing wherein the electromagnetic wave shielding layer is a layer formed using the resin housing covering sheet described in any one of claims 1 to 3.

8. A method for manufacturing an electromagnetic wave shielding housing comprising a resin housing and an electromagnetic wave shielding layer covering at least a portion of the resin housing, The process includes a coating step of forming the electromagnetic wave shielding layer using a resin housing covering sheet according to any one of claims 1 to 3, A method for manufacturing an electromagnetic wave shielding housing, wherein the coating step is performed by one of the following methods: TOM molding, vacuum forming, pressure forming, vacuum pressure forming, press forming, or injection molding.

9. A method for manufacturing an electromagnetic wave shielding housing comprising a resin housing and an electromagnetic wave shielding layer covering at least a portion of the resin housing, A coating step of forming the electromagnetic wave shielding layer using the laminated sheet according to any one of claims 4 to 6, The process includes removing layers other than the electromagnetic wave shielding layer from the laminated sheet after the coating process, A method for manufacturing an electromagnetic wave shielding housing, wherein the coating step is performed by one of the following methods: TOM molding, vacuum forming, pressure forming, vacuum pressure forming, press forming, or injection molding.

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