JPS60177699A - Method of producing electromagnetic wave shielding housing - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention not only has excellent electromagnetic wave shielding properties, but also has at least one shape selected from the group consisting of metal mats, cloths, and nets, and a thermoplastic resin or a composition thereof. The present invention relates to a method for manufacturing a casing that has good adhesion to objects. More specifically, an electromagnetic wave shielding casing is formed by laminating a thin-walled material made of at least one shaped material selected from the group consisting of metal mats, cloths, and nets, and a thermoplastic resin or a composition thereof. In this method, the thin-walled article is inserted into a mold of an injection molding machine in advance, and the thermoplastic resin or its composition is heated to a temperature higher than the melting point or softening point of the thermoplastic resin. The present invention relates to a method for manufacturing an electromagnetic wave shielding casing, which is characterized by injection molding onto the inner and/or outer surfaces of the thin-walled material in a temperature range that does not cause deterioration, and which not only has good electromagnetic wave shielding properties but also can be easily manufactured. The object of the present invention is to provide a casing that has excellent adhesion between at least one shaped object selected from the group consisting of metal mats, cloth, and nets and a thermoplastic resin or a composition thereof. .

[II] Background of the Invention With the advancement of industry and the standard of home life, the sources of electromagnetic radiation are increasing. Therefore, leakage of electromagnetic waves can cause dangerous harm to the human body and damage to ICs in electronic equipment.
This has resulted in negative effects such as malfunction, and has become a serious social problem. In particular, electromagnetic waves emitted from computers and various office processing equipment are causing trouble to televisions and audio equipment.

Furthermore, in the field of automobiles, electronic devices are being used for automatic control devices for various devices including engines, as well as speedometers, tachometers, and the like. Furthermore, it has come equipped with a microcomputer. Also,
Electronic devices such as telephones, radios, and televisions are being installed inside automobiles to improve comfort. These various electronic devices are subject to problems such as malfunctions due to electromagnetic waves emitted from the engine and electromagnetic waves from outside.

For these reasons, various methods have been adopted in recent years to shield electromagnetic waves.

- Because metal has the property of absorbing or reflecting electromagnetic waves, it is effectively used as an electromagnetic wave shielding material for electronic cameras and various communication devices. We also use thermal spraying, vapor deposition, and painting of metal on plastic for the same purpose.
Plating etc. are also applied. 'Furthermore, materials obtained by incorporating relatively large amounts of additives such as carbon powder and metal powder into plastics are also used.

However, the methods of using metal as a material or applying treatments such as metal spraying to plastics have drawbacks such as high specific gravity, poor workability, difficult processing methods, and high processing costs. be.

Further, regarding the method of mixing additives, if a small amount of the additive is mixed, the effect cannot be fully exhibited. On the other hand, if a large amount is mixed in, the effect can be exhibited, but there is a drawback that the mechanical strength of the resulting molded product is significantly reduced.

From the above, it is conceivable to manufacture an electromagnetic shielding material by injection molding using a thermoplastic resin or a composition thereof. Among these injection molding methods, electromagnetic waves are shielded by using a conductive thermoplastic resin or composition on one side or core layer (center part) of the molded product using a method such as two-color molding or strut-form molding. things are being done. In these methods, since it is necessary to increase the content of the conductive substance, the fluidity of the composition is poor and the molded product is likely to short-circuit. However, even if the composition has appropriate fluidity, if the conductive substance added is in the form of flakes or long fibers, the fluidity of the composition as a whole may not be uniform. Therefore, in high-speed, high-pressure injection molding, conductive substances are not dispersed uniformly and tend to be unevenly distributed.

For this reason, it is not possible to fully demonstrate its function, and it cannot be said to be economical because it is trying to achieve its effect by using a thick shape for the purpose associated with this. Furthermore, in methods such as the strafe form, although the equipment scale of the mold and molding machine is large, the market size for using 'I' as a magnetic shielding material is generally small due to model changes, and the cost is low. Targeted products tend to be limited because they do not match.

[In] Structure of the Invention Based on the above, the present inventors have searched various ways to obtain a casing that not only has excellent electromagnetic wave shielding properties but also can be obtained using a simple method, and as a result, they have developed a metal mat. , cloth, and net (hereinafter referred to as "metallic shape") selected from the group consisting of cloth and net. In this method, the thin-walled material is inserted into a mold of an injection molding machine in advance, and a thermoplastic resin or its composition is heated to a temperature higher than the melting point or softening point of the thermoplastic resin. However, the casing obtained by injection molding the inner and/or outer surface of the thin-walled material within a temperature range in which the thermoplastic resin does not deteriorate not only has excellent electromagnetic wave shielding properties but also can be easily obtained. They discovered this and arrived at the present invention.

[IV] Effects and Applications of the Invention The casing obtained by the method of the present invention, including its manufacturing method, exhibits the following effects (features).

(1) High electromagnetic wave shielding performance can be obtained because a metal shape with good conductivity is used as the electromagnetic wave shielding material of the housing.

(2) By using an electromagnetic wave shielding material in which a conductive material is uniformly dispersed in the housing, the housing itself has high electromagnetic shielding performance, and at the same time, the metal shape fused to the housing provides high electromagnetic shielding performance. A synergistic effect can be obtained.

(3) Since very high electromagnetic wave shielding performance can be obtained by the metallic shape, the thickness of the casing in which the conductive material is uniformly dispersed can be made thin without significantly reducing the electromagnetic wave shielding performance.

(4) Even if a material that does not contain a conductive substance is used for the casing, it is possible to put it into practical use by utilizing the high electromagnetic wave shielding performance of the metal shape. In this case, it is not only possible to maintain sufficient mechanical strength even if the casing is made even thinner than in (2) and (3) above, but it is also possible to select a material with good moldability. It can be taken widely.

(5) Since the manufacturing method of the casing of the present invention can be made thinner than those obtained by other methods with the same electromagnetic shielding performance and mechanical strength, the electromagnetic shielding casing as a whole is lighter. It is therefore economical.

(6) Secondary processing costs required for electromagnetic wave shielding treatment (for example, metal spraying, conductive coating, plating, etc.) are unnecessary, resulting in a significant cost reduction.

The electromagnetic wave shielding material obtained by the present invention not only has excellent electromagnetic wave shielding performance, but also has a good double effect, so it can be used in a wide variety of fields. Typical uses are shown below.

(1) Housing materials for office equipment such as fax machines, printers, word processors, etc. (2) Housing materials and structural materials for computers such as office computers, large computers, and microcomputers (3) For consumer home appliances such as televisions, videos, air conditioners, and sewing machines. Housing materials for electronic equipment such as communication equipment, various measuring instruments, medical equipment, etc. (4) Protective cases for various instruments in automobiles (5) Housing materials for various control devices in automobiles (6)
) Wiring covers for electric wires in automobiles, home appliances, and OA equipment (
For example, °, furnace tube) (7) Housing material for control equipment such as NC machine tools and industrial robots in the industrial field [V] Detailed description of the invention (A) Thermoplastic resin Housing for shielding electromagnetic waves of the present invention Thermoplastic resins used to manufacture thermoplastic resins are widely produced industrially and used in a wide range of fields, and their processing methods and various physical properties are well known. . Their molecular weight varies depending on the type, but is generally between 10,000 and 1,000,000. Typical thermoplastic resins include 7/mer Eidoku polymers with double bonds such as ethylene, propylene, vinyl chloride, and styrene;
Copolymers containing these as main components (50!L [northern]), copolymers of styrene and acrylonitrile (AS resins),
Resin whose main component is methyl meccrylate (HMA resin), butadiene homopolymer rubber, acrylonitrile-butadiene copolymer rubber (NBR), styrene-butadiene copolymer rubber (SBR), acrylic rubber, ethylene-propylene copolymer rubber ( EPR), ethylene-propylene-diene ternary copolymer rubber (EPDM), and chlorinated polyethylene rubber by graft copolymerization of styrene alone or styrene with other vinyl compounds (e.g., acrylonitrile, methyl meccrylate). Graft copolymer resins obtained by
BT), and polyphenylene ether resins include polycarbonate-1 resin. According to S et al., even if these thermoplastic resins are modified by grafting an organic compound having at least one double bond (for example, an unsaturated carboxylic acid or its anhydride), they do not have electromagnetic shielding properties. It is also possible to use a material that does not damage the material and has excellent workability. In addition, if the electromagnetic wave shielding material is particularly required to have impact resistance, the rubber used in the production of the graft copolymer resin described above may be blended as long as it has good compatibility and processability. It's okay. At this time, the proportion of rubber in the total amount of thermoplastic resin and rubber is usually at most 30% by weight2 (preferably 20% by weight).
weight 2 or less).

The electromagnetic wave shielding casing of the present invention can be obtained by using any of the above thermoplastic resins (including mixtures) by the injection molding method described below.

Furthermore, electromagnetic wave shielding properties can be improved by incorporating a conductive substance described below. Further, the electromagnetic wave shielding casing obtained by the present invention is mainly used in the fields of electronic equipment industry, home appliance industry, and automobile industry as described above, and in these fields, flame-retardant parts and casings (housings) are used. materials) etc. are requested. For this purpose, a casing having desired flame retardancy can be obtained by adding one or more of the halogen-containing organic compounds, antimony oxide, and hydrated inorganic substances described below.

(B) Conductive substance Further, the conductive substance used in the present invention includes metals such as aluminum, iron, copper, ferrite, zinc, and silver, alloys based on these metals (e.g., brass, stainless steel), Examples include ferrite and conductive carbon black. In particular, further effects can be exhibited by using these metals or alloys together with conductive carbon black.

Among these conductive substances, metals, alloys, and ferrites are in the form of powders, fibers, and flakes, and the average size of the powders is generally between 250 mesh and 20 mesh. It's mesh. Furthermore, as a fibrous material, its diameter is generally 0.0020
~0.20 mm, and lengths of 10 mm or less are desirable because they are easier to process. Furthermore, as a flake-like material, the cross-sectional area is 0. IXo, any shape such as circular, square, rectangular, rectangular with dimensions from 1 mm to 5×5III11 can be used, but among them, about 1×1 mm
A rectangular shape with a membrane area of about 0.03 mm in thickness has good dispersibility. The flakes of the conductive material have good dispersibility in the thermoplastic resin, and unlike fibrous materials, they do not become entangled with themselves to form beads. Also,
There is a strong tendency to mix it along the flow direction of the thermal 5T plastic resin during molding, and when mixed in the same amount, it not only has good conductivity but also improves the bending elastic modulus. Among others, IX 1mn+
A flake-like material having a surface area of is most preferred from the viewpoint of dispersibility. These powdery, fibrous, or flake-like materials may be used alone, but by using two or more of them together, the effects of the present invention can be achieved with a small mixing ratio. This is suitable because it allows for

In addition, the conductive carbon black used in the present invention generally has a specific surface area of 20 to 1800 m'/g and a pore volume of 30 to 7500 m/g as measured by low temperature nitrogen adsorption method and BET method. The range is 1.5 to 4.0 cc/g as measured by mercury porosimetry, and those with a specific surface area of 600 to 1200 m'/g are particularly effective.

Examples of the carbon black include channel black, acetylene black, and carbon black produced by the furnace black method. For more information on these carbon blacks, please refer to “Carbon Bragg Association”
``Carbon Black Handbook'' (published by Tosho Publishing Co., Ltd. in 1972), Rubber Digest Co., Ltd., ``°Handbook, Rubber, Plastic Compounded Chemicals'' (Rubber Digest Co., Ltd., published in 1971), the above-mentioned ``Synthetic Rubber Huff 1'' Book °° Their manufacturing methods and physical properties are well known.

(C) #Fumigating agent Further, the flame retardant used in the present invention is a halogen-containing organic compound, antimony diluted and a hydrous inorganic substance.

(1) Halogen-containing organic compounds Among these flame retardants, halogen-containing organic compounds are widely known as flame retardants. Representative examples include tetrachlorophthalic anhydride, chlorinated paraffin, chlorinated bisphenol A, brominated bisphenol S,
Mention may be made of chlorinated diphenyl, brominated diphenyl, chlorinated naphthalene, tris(β-chloroethyl) phosphate and tris(dibromobutyl) phosphate. The /\halogen content of the halogen-containing organic compound is generally 20 to 80% by weight, preferably 30 to 80% by weight, and particularly preferably 40 to 85% by weight. The halogen-containing organic compound is liquid or solid at room temperature (20°C), but the decomposition initiation temperature or Kuma 11 point is 200°C.
Temperatures above ℃ are desirable. Furthermore, the molecular weight is usually 300
-5,000, and particularly preferably 300-4,000.

(2) Antimony oxide Further, antimony oxide is generally used as a flame retardant aid for the halogen-containing organic compound.

Representative examples include antimony trioxide and antimony pentoxide.

These halogen-containing organic compounds and antimony oxide are well known from the above-mentioned ``Handbook of Chemicals Compounded with Rubber and Plastics.''

(3) Water-containing inorganic substance The water-containing inorganic substance contains a bound water amount of 10 to 80% by weight, and has a true specific gravity of 1.0 to 5.0. Furthermore, it does not generate moisture during kneading to produce the composition and injection molding to produce the housing, but it does generate moisture at higher temperatures (preferably 300°C or higher). Preferably. The crosstalk and injection molding processing temperatures differ depending on the type of thermoplastic resin used, and these temperatures will be shown below. Typical examples of water-containing inorganic substances include Group II A, II
Group B and mB group metals and aquariums containing these metals. The hydrated inorganic substance includes magnesium hydroxide,
Calcium hydroxide, aluminum hydroxide (A or 303n H2O), hydrated gypsum, kaolin clay, calcium carbonate, hydrotalcite, basic magnesium carbonate, magnesium borate, precipitated barium sulfate, etc. Examples include compounds that contain water. These water-containing inorganic substances are poorly soluble in water, and the solubility in 100 cc of water is generally 10 g or less, preferably 1 g or less, particularly 0.0 g or less at a temperature of 20°C.
1 g or less is suitable. Suitable hydrous inorganic substances include:
aluminum hydroxide, hydroxide gypsum, magnesium hydroxide,
Calcium carbonate, basic magnesium carbonate, precipitated i&
M-magnesium and magnesium silicate (MgOψ
S i 02 ). Regarding these water-containing inorganic substances, their manufacturing methods, physical properties, and products are described in Rubber Digest Co., ed., "Handbook, Rubber and Plastic Compound Chemicals" (Rubber Digest Co., published in 1970), pages 221 to 253. It is well-known and has its name written on it.

The average particle size of these antimony diluted and hydrated inorganic substances is usually 0.1 to 100 microns, and 0.2 to 5 microns.
A thickness of 0 micron is desirable, and a diameter of 0.3 to 40 micron is particularly preferred.

(D) Composition ratio When producing the thermoplastic resin composition of the present invention, in a composition consisting of a thermoplastic resin and the conductive substance, the composition ratio of the conductive substance in the total amount thereof is usually at most 6.
0 capacity 2, preferably 50 capacity 2 or less, and particularly preferably 5 to 50 capacity 2. If the blending ratio of the conductive substance in the total amount of the thermoplastic resin and the conductive substance exceeds 80% by volume, it is not only difficult to obtain a homogeneous composition, but even if the composition is obtained, However, it is not preferable because it is difficult to form into a sheet and to produce a good electromagnetic shielding material. As mentioned above, as conductive substances, [metal or alloy powder, FjA fibrous proboscis-like material and/or flake-like material] (hereinafter referred to as "metal powder, etc.") and conductive carbon black are used. (It is preferable to use Jl, but when used together, the capacity ratio of metal powder etc. and conductive carbon black is 4.0
A range of 1:1 to 4.0 is desirable, and a range of 3.5:1 to 1:3.5 is particularly preferred. In particular, conductive carbon black has a shielding effect in the low frequency range (In) and high frequency range (kHz
) by mixing powdered metals that have an electromagnetic wave shielding effect, it not only shows a shielding effect over a wider frequency range, but also shows a shielding effect over a wider frequency range. It was discovered that a remarkable shielding effect can be achieved by using both (31).The reason for this remarkable effect is not clear, but the electromagnetic wave energy that is fouled or absorbed by metal powder, etc. It is presumed that the electrical conductivity of the composition of the present invention is significantly improved by using electrically conductive carbon black as a medium. When using metal powder, etc., using aluminum or its alloy as the metal is not only lightweight (low density), has good electromagnetic wave shielding properties and plasticity, but also has good properties during kneading as described below. It is also suitable for preventing damage to the mixer and molding machine during molding.

In addition, when adding antimony oxide and a halogen-containing organic compound to impart flame retardancy to the electromagnetic wave shielding casing of the present invention, the blending ratio of the halogen-containing organic compound and antimony oxide to 100 parts by weight of the thermoplastic resin is The combined amount is at most 50 parts by weight, preferably 5 parts by weight or more, and particularly preferably 10 to 45 parts by weight in total. Furthermore, the blending ratio of antimony oxide to the amount of halogen element in 100 parts by weight of the halogen-containing organic compound is:
Generally, it is 100 to 600 parts by weight, and 100 to 40 parts by weight.
It is preferably 0 parts by weight, and particularly preferably 150 to 400 parts by weight from the viewpoint of flame retardancy and bleedability.

In addition, when blending conductive carbon black as a conductive substance, at most 50 parts by weight (preferably 1 part by weight of 45 parts) of a hydrous inorganic substance should be blended with 100 parts by weight of the thermoplastic resin. It is.

However, it is necessary that at least 5 parts by weight (preferably 10 parts by weight) of the hydrated inorganic material be blended with respect to 100 parts by weight of the conductive carbon black.

By blending a water-containing inorganic substance within these ranges, an electromagnetic wave shielding casing with good flame retardancy can be manufactured.

When at least one of ferrite and conductive carbon black, such as metal powder, and a flame retardant are used in combination with a thermoplastic resin, the total amount of these in the composition is at most 65% by volume, 60 capacity 2 or less is desirable, and 55 capacity 2 or less is particularly suitable.

(E) Production of composition In producing the electromagnetic wave shielding casing of the present invention, a thermoplastic resin or a composition comprising a thermoplastic resin, a conductive substance, and/or a flame retardant may be used. , stabilizers against oxygen, light (ultraviolet light) and heat, metal deterioration prevention agents commonly used in the field of thermoplastic resins, thermoplastic resins or thermoplastic resins and conductive substances and/or flame retardants, respectively. Agents, plasticizers, fillers, lubricants, and processing improvers may be blended (added).

In order to produce the thermoplastic resin composition of the present invention, tri-blending may be carried out using a four-combination machine such as a Henschel mixer, which is commonly used in the respective thermoplastic resin industries, a Banbury mixer, a Niegoux mixer, etc. , by melt-kneading using a mixer such as a roll mill and a single-screw extruder. At this time, a homogeneous composition can be obtained by performing dry blending at least once in advance and then melt-kneading the resulting composition (1 compound) at least once.

In this case, each composition is generally melt-kneaded and then formed into pellets, which are then subjected to injection molding as described below.

(F) Metallic shaped objects The metallic shaped objects used in the present invention are metallic mats, cloths, and nets, and include aluminum, iron,
A fibrous material whose main component is at least one metal selected from the group consisting of metals such as copper and nickel and alloys containing these as main components (e.g. brass, brass, stainless steel) is processed into a mat shape. It is also woven or braided in the form of a cross or net. i! The diameter of the filamentous proboscis is usually 0.
0020 to I+nm, preferably 0.01 to 0.5 mm, particularly 0.0020 to I+nm, preferably 0.01 to 0.5 mm. O1 to 0.2+nm is suitable. Although it depends on the shape of the molded product, a braided steel wire is preferable because it has elasticity in the vertical and horizontal directions. The mesh size of the mesh is important for determining the electromagnetic wave shielding performance. The mesh size is smaller than 2 meshes. If a material rougher than 2 mesh is used, the electromagnetic wave shielding performance will be significantly reduced. In particular, for devices that require shielding performance in the high frequency (Mn2) band because the size of the mesh depends on the wavelength to be shielded from electromagnetic waves, 2 meshes or more (more fine-grained than 2 meshes) are required, and 12 meshes or more are required. A finer mesh is preferable, particularly a finer mesh than 20 meshes. The larger the size (the smaller the mesh size), the more desirable it is in order to have the ability to shield high-frequency electromagnetic waves.

In addition, conductive paints containing nickel, carbon, etc. are applied to the surface of mats, nets, or cloths made from ordinary thermoplastic resins, and nickel, aluminum, etc. are applied to the surface by vacuum deposition. Although it is possible to use a metalized material, it is natural that a material mainly made of the above-mentioned metal fibers is preferable because it imparts uniform conductivity.

To manufacture the casing of the present invention, the object can be achieved by laminating the above thermoplastic resin and metallic shape. Generally, thermoplastic resin and metal do not have sufficient adhesion to each other. Furthermore, even if the thermoplastic resin layer of the present invention and the metallic shaped object are in close contact with each other under normal conditions, they may peel off due to a change in temperature, a slight impact, vibration, or the like. For these reasons, it is preferable to interpose an adhesion imparting agent between the thermoplastic resin and the metallic shape.

(G) Adhesive agent As a method for intervening an adhesion agent, there is a method in which the adhesion agent is directly melted or adhered to the metallic object, and a method in which the adhesion agent is directly melted or adhered to the metallic object (= J agent and thermoplastic resin or
Structility parameter (hereinafter referred to as "rSP value")
This is a method in which a thermoplastic resin and another type of thermoplastic resin of 1.0 or less (preferably 0.5 or less) are interposed in this order.

The adhesion promoter used in the former method varies depending on the type of thermoplastic resin in the thermoplastic resin layer.
Craft products obtained by grafting unsaturated carboxylic acids or derivatives thereof (such as anhydrides) onto thermoplastic resins of the same type as thermoplastic resins, and combinations of thermoplastic resin monomers and unsaturated carboxylic acids or derivatives thereof. Examples include polymers. For example, if a propylene polymer (a propylene homopolymer or a propylene-based copolymer) is used as the thermoplastic resin in the thermoplastic resin layer, maleic acid or maleic anhydride is grafted onto the propylene polymer. When using a styrene polymer (styrene homopolymer, high-impact polystyrene) as the graft material or thermoplastic resin obtained by Alternatively, a graft product obtained by graft polymerization of the anhydride thereof can be mentioned.

On the other hand, the adhesion imparting agent used in the latter method may be any agent as long as it can firmly adhere to the metallic shape. Typical examples of the adhesion imparting agent include polyurethane adhesives, epoxy resins, polyester resins, acrylic resins, and cyanoacrylate resins. Among these adhesion promoters, polyurethane adhesives are particularly preferred because they have good durability in cold/hot cycles and high temperature environments, and have high adhesive strength. Polyurethane adhesives are basically obtained by reacting any one of polyester polyols, polyether polyols, and polyurethane polyols with diisocyanates.

These adhesion imparting agents are generally widely used, and are described, for example, in the "Adhesion Handbook" edited by the Japan Adhesive Association.
(published by Nikkan Kogyo Shinmasha on November 10, 1980).

In addition, thermoplastic resins with a SP value difference of 1.0 or less between the thermoplastic resins of the thermoplastic resin layer used in the latter method are co-authored by Akita, Bengami, and Nishi.
(December 8, 1981, published by CMC) No. 71
The difference in SP values listed on page 72 is 1. It only needs to be less than or equal to θ, and can be determined by calculation.

As an example, polydimethylphenylene oxide (PPO), PP is used as the thermoplastic resin of the thermoplastic resin layer.
If either a blend of O and a styrene polymer or a grafted product obtained by graft polymerizing styrene to PPO are used, the styrenic polymer poly(α-methylstyrene, poly-α-methylstyrene) is used. ) and styrene-chlorostyrene copolymers.

In manufacturing the casing of the present invention, as a method of interposing an adhesion agent between the thermoplastic resin layer and the metal shaped object, in the former method, the adhesion imparting agent is applied to the metal shaped object in a film. A method in which a metal shape is heated and laminated, a method in which a solvent in which an adhesion imparting agent is dissolved is applied to a metallic shape, and the solvent is evaporated to remove and dry; a method in which the solvent is sprayed to remove and dry. There are ways to do this. On the other hand, in the latter method, the same type of resin as the thermoplastic resin of the thermoplastic resin layer or the thermoplastic resin of the thermoplastic resin layer and SP This is a method in which thermoplastic resin films with a difference in value of 1.0 or less are bonded together by heating, pressure, etc. For these methods, methods generally used for bonding metallic shapes and thermoplastic resins may be applied. The total thickness of the tackifier in the former method and the tackifier and film in the latter method is generally 10 to 500 microns, preferably 250 microns or less.

(H) Housing The housing of the present invention has the following properties: heat of 6 pf, ij resin layer and metallic shape, or the adhesion imparting agent or the thermoplasticity of the adhesion imparting agent and thermoplastic resin layer between them. It can be produced by interposing another thermoplastic resin that is the same type as the resin or has an SP value difference of 1.0 or less from the thermoplastic resin.

It is necessary that the coverage ratio of the metallic shape to the casing be as close as possible to the surface area of the casing. However, when a thermoplastic resin is molded into a housing for an electrical device, an electronic device, etc. by the molding method described below, openings such as windows and grids are often required for functionality. Even if the entire housing is covered with a metallic object, it may not be possible to completely cover the internal devices. Furthermore, there are bosses, ribs, or four parts inside the casing, which do not follow well during molding, and may create openings in the metal shape. Even in that case, by molding metal shapes on both the casing surface and the opening surface using the method described later, the internal equipment can be made into a completely ideal system. Here, the coverage ratio of the metal shape to the casing is C, the total surface area of either the outside or the inside of the casing is S), and either the outside or the inside of the casing of the metal shape is When the surface area to be covered is SM, it is expressed as C=S/SH. In the present invention,
C is preferably 273 or more, particularly preferably 38 or more, and particularly preferably 415 or more. If the casing coating (C) of the metallic object is less than 273, the expected electromagnetic wave shielding effect cannot be obtained.

As described above, since the casing functionally requires an opening such as a window and a recess, it is difficult to completely cover the metal shape in the casing (ie, C is less than 1). In such a case, it is preferable that the maximum dimension of the cut in the metallic shape is 174 or less of the wavelength of the electromagnetic wave, especially 1
/100 or less is suitable. If the cut exceeds 18 wavelengths, the electromagnetic wave shielding effect will not be sufficient.

Furthermore, in order to improve the adhesion between the thermoplastic resin layer and the metallic shape, an adhesion agent or an adhesion imparting agent is added to the same type of thermoplastic resin as the thermoplastic resin of the thermoplastic resin layer or its SP value. Thermoplastic resins with a difference of 1.0 or less may be used. In this case, their thickness is usually between 1 micron and 1 mm, preferably between l[theta] and 500 microns, especially between 15 and 300 microns.

Even if the thickness exceeds 1 mm, it is meaningless because the adhesiveness cannot be further improved.

(J) Housing manufacturing method In manufacturing the housing of the present invention, insert injection molding is used during molding of the housing for the purpose of reducing man-hours and improving the adhesion between the thermoplastic resin layer and the metal shaped object. Do the following. In insert molding, in the first step, 74 rI (8'U of the plastic resin layer (same type as the plastic resin or thermoplastic resin A metallic shaped object laminated with a thermoplastic resin with an SP value and a difference of 1.0 or less is inserted between the male mold and the ω mold of an injection molding machine, and is laminated so that one side is a metal surface. When using a metallic shaped object, the thermoplastic resin being molded during molding fuses with the thermoplastic resin laminated with the metallic shape, and the metal surface comes into contact with the male or female mold. When the mold is closed, the metal shape or the laminated metal shape must deform sufficiently according to the unevenness of the mold. If it is insufficient, the situation will be the same as when a foreign object is inserted into the mold, and the mold cannot be clamped because the mold clamping pressure is not turned on.In addition, in the second stage, the pressure from the gate of the mold The thermoplastic resin of the thermoplastic resin layer is filled into the mold, and at this time, the metal shape or laminated metal shape retains sufficient flexibility due to the pressure of the resin and becomes male or female. It must adhere sufficiently. If the metal shape or laminated metal shape does not adhere tightly to the mold, the molded product may be deformed or the weight may be inconsistent, resulting in defective products. Note that if the manufactured casing is shallow, the metal shape or laminated metal shape can follow the mold by elongation of the metal shape without being processed beforehand. Therefore, insert injection molding is possible by simply inserting a metal shape or laminated metal shape between a male mold and a female mold.However, if the casing is deep, the metal shape or laminated 1.) Shape 13ij :)
It is desirable to carry out n+ machining.

The above insert injection molding will be explained in an easy-to-understand manner using drawings. FIG. 1 is a sectional view before molding when the casing to be manufactured is relatively shallow, and FIG. 2 is a sectional view when the metal shape of the casing is deep and has been pre-processed. FIG. 3 is a sectional view before molding. FIG. 3-1 is a sectional view after molding when the casing is shallow, and FIG. 3-2 is a sectional view after molding when the casing is deep. In Figures 1 and 3-1 and 3-2, 1 is a male mold, and 2 is a female mold. In addition, 3 is a metallic shaped object or a laminated metallic shaped object]:,, so,
4 is a thermoplastic resin layer. Furthermore, 5 is a female type gate. In addition, Figure 4-L is a partially enlarged cross-sectional view in the case where the manufactured casing is composed of a metal shaped object and a thermoplastic resin layer, and Figure 4-2 is a partial enlarged sectional view of the case where the manufactured casing consists of a metal shaped object and a thermoplastic resin layer. FIG. 3 is a partially enlarged cross-sectional view when a sex imparting agent is present. Furthermore, Fig. 4-3 shows that the metallic shaped object in the casing is of the same type as the adhesion imparting agent and the thermoplastic resin of the thermoplastic resin layer, or the difference in SP value from the thermoplastic resin of the thermoplastic resin layer is 1.0 or less. FIG. 3 is a partially enlarged cross-sectional view of a case where a thermoplastic resin is interposed. In FIGS. 4-1 to 4-3, a is a metal shaped object, and b is a thermoplastic resin layer. In Figures 4-2 and 4-3, C is an adhesion imparting agent. Further, in FIG. 4-3, d is the same type as the thermoplastic resin of the thermoplastic resin layer, or the difference in SP value is 1.
0 or less thermoplastic resin layer.

In addition, although Figs. 1 and 2, and Figs. 3-1 and 3-2 show cases in which a metal shaped object is fused to the inside of the casing, by completely reversing these cases, By fusing it to the outside of the casing, it is possible to make the surface look beautiful as if it had been metallized.

For insert injection molding, the resin temperature must be above the melting or softening point of the thermoplastic resin of the thermoplastic layer, but below the pyrolysis temperature. The resin temperature varies depending on the type of thermoplastic resin used, but typical examples are 170 to 290°C for propylene polymers, and 170 to 290°C for ABS resins.
70-280'C.

In addition, if the injection pressure is 40 kg/crn' or more at the gauge pressure at the nozzle of the cylinder of the injection molding machine, it is possible not only to form the thermoplastic resin into a shape almost similar to the shape of the housing, but also to improve the appearance. You can also get a unified view. Therefore, it is generally 40 to 140 kg/cm', and preferably 70 to 120 kg/cm'.

[IV] Examples and Comparative Examples -1 The present invention will be explained in more detail with reference to Examples.

In addition, in the examples and comparative examples, the melt flow index (hereinafter referred to as rMFI J) is in accordance with JIS K-6.
758, the temperature is 230°C and the load is 2.
The measurement was carried out under the condition of 113 kg. In addition, the adhesive strength is AST
Measured according to MD-3359. Furthermore, the measurement of the electromagnetic wave shielding effect was carried out using a metal shaped object whose inner dimensions were 15 x 15 cm, manufactured by the insert injection molding method.
Sample boxes with an opening internal dimension of 16 x 18 cm, a height of 20 cm and a thickness of 3) were manufactured and two of these boxes were fitted together. A porta-pull oscillator was adjusted to a predetermined frequency (250M&) and placed in the fitted box. This box was placed in an anechoic chamber, and the radio waves emitted from the transmitter inside the box were measured using a receiving antenna using a microwave power meter after passing through a detector. The radio waves from the transmitter were similarly measured without the box manufactured by the metal insert injection molding method, and the ratio of the electrolytic strength (pV) with and without the sample box was expressed in decibels (dB). It was taken as the electromagnetic wave attenuation of the shaped insert box.

The manufacturing method, physical properties, etc. of the thermal I]f plastic resin and composition (mixture) used in the Examples and Comparative Examples are shown below.

[(A) Olefin polymer)] Density is 0.900 g/c as an olefin polymer
m' propylene homopolymer [MFl 4.2g7
10 minutes, hereinafter referred to as rPP(1) J] and a propylene-ethylene block copolymer with a density of 0.900 g/cm' [MFI 12.Og'/10 minutes, hereinafter referred to as rPP(2) J1. It was used.

[(B) Modified propylene polymer (modified PP)] 100 parts by weight of the above PP (1), 2.5 parts by weight of 0.01 part by weight
-Dimethyl-2,5-di(butylperoxy)hexane (as an organic peroxide) and maleic anhydride were pre-triblended for 5 minutes using a Henschel mixer. The obtained mixture was passed through an extruder (diameter 40+
A modified polypropylene resin (hereinafter referred to as "modified PPJ") was prepared by melt-kneading using a resin temperature of 230°C (230°C).The content of maleic anhydride in this modified PP was 0.6% by weight2. Ta.

[(C) fiflammable block rolopyrene copolymer flame retardant P
P) ] Wl as a flammable block propylene copolymer, 100 parts by weight of PP (2) of 2, 27 parts by weight of dechlorane which is a dimer of hexanechlorocyclopentadiene, and 1
3 parts by weight of antimony trioxide (average particle size 1.0 microns) was pre-triblended for 5 minutes using a Henschel mixer. The resulting mixture was passed through an extruder (dia.
The resulting composition (pellets) was made into a flame-retardant block polypropylene copolymer (hereinafter referred to as "flame-retardant PPJ"). The flame retardancy of this flame-retardant PP was measured according to the ASTM D-[135 flame retardant test method at a thickness of 1/8 inch, and it was found to be self-extinguishing.
-6870 at a temperature of 230° C. and a load of 2.113 kg) was 2.0 g/40 min.

[(D) Styrenic resin (PS)] As a styrene resin, styrene is suspended in water, an emulsifier and a catalyst are added, and polymerized at a temperature of 90°C.
Styrenic resin (hereinafter referred to as rP
SJ) was manufactured and used.

[(E) Styrene resin (HIPS)] As the styrene resin, 8.1 parts by weight of styrene-butadiene random copolymer rubber [Styrene content M 25.3 Nail f1%
, M = viscosity (Ml, 1+4) , 25, hereinafter rSB
RJ was graft-polymerized with 82 parts by weight of styrene to produce high-impact polystyrene (hereinafter referred to as rHIPSJ) with a melt flow rate of 13.0 g/10 minutes.

[(F) Modified styrenic resin (modified PS)] Tri-blended under exactly the same conditions as the modified PP except that the above PS was used instead of the pp(+) used in producing the above modified PP. Then, a modified styrene resin (hereinafter referred to as modified PSJ) was produced and used. The content of anhydrous leic acid in this modified PS is 0,
It was 2% by weight.

[(G) W compound (modified PPO)] 2.6-xylenol is polycondensed by a solubilization coupling method to form poly2
, 6-dimethylphenylene-1,4-ether [intrinsic viscosity (30' (!, in chloroform)) 11 constant, unit d/'g) 0.53 or less rPPOj] was produced. 100 parts by weight of PIPO, 25 parts by weight of styrene intermediate, 10 parts by weight of PS produced in the above (A)
and 2.1 parts by weight of di-tertiary-butyl-oxide were mixed for 10 minutes using a Henschel mixer, and then transferred to a twin-screw extruder (diameter 30 + nm, resin temperature 270'O).
A styrene-grafted PPO mixture was produced using

50 parts by weight of the PPO mixture (this styrene graph) and 50 parts by weight of the PS produced in (D) above were added to the mixture (
Triblending was carried out in the same manner as in the production of 1). The obtained mixture was transferred to an extruder (diameter 40 mm, resin temperature 260 mm).
°C) while melt-kneading the mixture [hereinafter referred to as “modified P
P0J] was produced.

[(H) Acrylonitrile-chlorinated polyethylene-styrene graft copolymer resin (ACS)] Chlorinated polyethylene with a Mooney viscosity (MSl+4) of 76 (chlorine content 40.6 weight, jml, %,
Molecular weight of raw material polyethylene: approx. 200,000) 1f100g,
320 g of polyvinyl alcohol (saponification degree 95%) and 8.1 g of ice (ion exchange water) were charged. The mixture was then heated to room temperature (approximately 23°C) and stirred vigorously. Add 4 as the tIi M form to this dispersion while stirring at room temperature.
5130 g of styrene and 1520 g of acrylonitrile, 320 g of fluidized crude oil as a lubricant, 16.0 g of tertiary methyl chloride acetate as a polymerization initiator and 16.0 g of tertiary as a chain transfer agent. Dodecyl mercaptan was added. The suspension of this reaction system is -
After replacing the L part with nitrogen gas, the temperature was kept at 105°Q4. After polymerization was carried out at this temperature for 4 hours with stirring, the polymerization was further carried out at a temperature of 145°C for 2 hours. After this reaction system was allowed to cool to room temperature, the obtained polymer (graft material) was filtered and thoroughly washed with water. The obtained grafted product was heated at 50°C to -
・Drying was carried out under reduced pressure day and night. The polymerization conversion rate (based on the single tube used in the polymerization) was 95.4%, and the product was in the form of a slightly coarse powder. In addition, this grafted product [hereinafter referred to as F' rA
The content of solids (referred to as CS J) was 20.3% by weight.

[(J) Acrylonitrile-butadiene-styrene ternary copolymer rubber (ABS resin)] Styrene-butadiene copolymer rubber (butadiene content: 80% by weight, rubber gel content: 80%) in a 20-piece stainless steel autoclave.
280.0g (as solid content), 2.0g ammonium persulfate, 80.0g disproportionated rosin ester,
21.0 g of lauryl mercaptan and 8.0 g of water were charged and stirred evenly. In addition to this, 25
20 g of styrene and 1200 g of acrylonitrile were added and stirred, then allowed to warm to 70° C. with stirring. Polymerization was carried out at this temperature for 10 hours with stirring.

An aqueous solution of 5% Mt W aluminum was then added to the latex containing the polymer (graft) obtained above to coagulate the resulting graft. This coagulated material is mixed with an aqueous solution of about 5.2 lz of thorium hydroxide.
Wash MI L using a sentence, and a larger amount (about 30 sentences) of 70
Washed using warm water at °C. Approximately 80% of this graft
Drying was carried out under reduced pressure at °C - day and night. As a result, 3785 g of white powdery graft material was obtained.

The Izot impact strength of the obtained graft was 7.5 kg.
・cm/cm-notch, tensile strength is 488kg/
cm". The Vicat softening point of this polymer was 101.5°C.

The rubber content of this graft was 7.3% by weight. Hereinafter, this graft product will be referred to as rABS J. This ABS melt flow rate) (JIS K-88
According to 130, the temperature is 200℃ and the load is 5kg.
) was 4.1 kg and 710 minutes.

[(K) Flame-retardant ABS] 62 weight parts of the above ABS, 25 parts by weight of dechlorane used in producing the above-mentioned flame-retardant PP, and +34'[l: parts] of antimony trioxide were mixed for 5 minutes using a Henschel mixer. Blended. The resulting mixture was passed through an extruder (diameter 5
0ml11) and the cylinder set temperature is 195°.
A composition (pellet) was produced and used while melt-kneading under the conditions of C. Hereinafter, the obtained composition will be referred to as flame-retardant ABS. When this flame retardancy test was carried out using ASTM Toro 35 and rated as X+++, it showed self-extinguishing property, and the self-extinguishing time was 2 seconds. In addition, melt flow rate (JIS
K-6870 at a temperature of 230° C. and a load of 2.18 kg) was 5.0 g/10 minutes.

[(L) Polyamide resin] A polyamide resin manufactured by ring-opening polymerization of ε-caprolactam with a density of 1.13 g/cm'' (melt viscosity at 250°C: 300
0 poise (hereinafter referred to as "nylon-6") was used.

[(M) Polybutylene terephthalate] Polybutylene terephthalate obtained by polymerizing terephthalic acid and 1,4-dibutanediol [density 1
．． 31g/crrf, melting point 224°C1 intrinsic viscosity [η]
1.1 (250°C), heat deformation humidity (4.8kg/
cm') 155°C1 or less rPBT J]
It was used.

Examples 1 to 27 2 mesh, 12 mesh and 80 mesh stainless gold P (hereinafter referred to as [St net] respectively),
24-mesh wire mesh (hereinafter referred to as "Cu net"),
24 mesh wire net (hereinafter referred to as rFe net),
30 micron stainless steel wire plain woven into 400 meshes (hereinafter referred to as "St cloth"), aluminum fibers, brass fibers, and brass fibers each having a diameter of 30 microns and a length of 10 mm, each with an average particle size of 42 meshes. Modified PPO powder was tri-blended at a volume ratio of 171 and press-processed into a sheet using a hydraulic press with a temperature of 1000°C set at 240°C (hereinafter referred to as ``rA Bunmat'' and ``Brass Mat''). ” and “brass matte”) on one side of each metal shape.
335) was coated to a dry thickness of 10 microns and dried (however, it was not coated in Examples 9 to 11 and Examples 21 to 24). On the other hand, each of the thermoplastic resins listed in the IF table was used as a laminating resin to form a film having a thickness of 50 microns using a T-Guy molding machine. A film of these thermoplastic resins (however, no film was used in Examples 9, 10, 11, and 17) was applied to the urethane primer coated surface of the metal shape using a roll at a rate of 10 kg/cm.
laminated under a pressure of m', and the laminate was
It was kept at 0°C for 4 days.

Injection molding machine (manufactured by Toshiba Machine Co., Ltd., model 1S-20)
The metallic shape obtained in the above manner was placed in a mold with a mold diameter of 2,000 tons (OA, clamping force: 2000 tons) so that the metallic shape was in contact with the male mold surface. The gauge pressure at the nozzle part of the cylinder of the injection molding machine is 80 kg for this metal shape.
A housing (sample box) was manufactured by injection molding the thermoplastic resins whose types are shown in Table 1 under the conditions where /cm' and the resin temperature at the nozzle part of the cylinder are shown in Table 1. .

Table 1 shows the ratio of the maximum dimension of the window to the wavelength of electromagnetic waves of the casing and the coverage ratio of the metallic shapes to the total area of the casing. The electromagnetic wave attenuation rate of the casing thus obtained was measured. The results are shown in Table 1.

Example 28 85 parts by volume and 15 parts by volume of hexagonal aluminum flakes (hereinafter referred to as "A-shaped flakes", membrane area 1 x 1 mm, thickness 0.03 mm) of the above-mentioned modified PP were mixed in advance in a Henschel mixer (volume ratio 11 Tri-blending was carried out uniformly for 5 minutes using 10% of the total weight. The obtained mixture was passed through an extruder (diameter 40 mm+, resin temperature 230°C)
Pellets were produced by melt-kneading using a .

Flame retardant P used as thermoplastic resin in Example 20
A casing was manufactured in the same manner as in Example 20, except that the pellets (composition) manufactured in this way were used instead of P. The electromagnetic wave attenuation rate of the obtained housing was determined to be 25 dB.

Example 29 70 parts by volume of the modified PP used in Example 28, 15 parts by volume of the A-patterned plate, and furnace black with an average particle size of about 30 millimeters [manufactured by Cabo 7 +- Co., Ltd., USA, trade name: Vulcan] ) XC knee 72,
Density 1.8g/cc, surface ill 220m'/gl1
5 parts by volume were triblended and melt-kneaded under the same conditions as in Example 28 to produce a composition (pellets).

A casing was manufactured in the same manner as in Example 28, except that the composition thus manufactured was used instead of the aforementioned composition used as the thermoplastic resin in Example 28. When the electromagnetic wave attenuation rate of the obtained housing was measured, it was 28 dB.

The cellophane tape of the metallic shape of the casing obtained as described above was adhered to the adhesive strength according to ASTM D-3355.
When measured according to the method, none of the metallic shapes were peeled off.

[Brief explanation of the drawing]

FIG. 1 is a sectional view before forming when the casing is shallow in the present invention, and FIG. 2 is a sectional view before forming when the metal shaped object is pre-processed when the casing is deep. It is a diagram. FIG. 3-1 is a sectional view after molding in a case where the casing is of a shallow type. Furthermore, FIG. 3-2 is a cross-sectional view after molding when the casing is a deep type. Also, the 4th-
Figure 1 is a partially enlarged cross-sectional view of the manufactured housing consisting of a metal shaped object and a thermoplastic resin layer, and Figure 4-2.
The figure is a partially enlarged cross-sectional view when the metallic shape in the m1 body is interposed with an adhesion-imparting agent, and Fig. 4-3 shows a case where the metallic shape in the casing is interposed between the adhesion-imparting agent and the thermoplastic resin layer. FIG. 2 is a partially enlarged cross-sectional view of a case in which a thermoplastic resin of the same type as the thermoplastic resin of or having a difference in SP value from the thermoplastic resin of the thermoplastic resin layer of 1.0 or less is interposed. ■...male mold of the mold, 2...female mold, 3...metallic shape or laminated metal shape, 4...thermoplastic resin layer, 5...female mold Gate a...
・Metallic shaped object, b...Thermoplastic resin layer, C...Adhesion imparting agent, d...Same type of thermoplastic resin as the thermoplastic resin layer or S
The difference in P value is 1.0 or less Thermoplastic resin layer Patent applicant Showa Denko Co., Ltd. Agent Patent attorney Sei Kikuchi Figure 1 Figure 2 Figure 3-1 Figure 3-2 Figure 4- Figure 1 Figure 4-2

Claims (1)

[Claims] To manufacture an electromagnetic wave shielding casing, which is made by laminating a thin object made of at least one type of shaped object selected from the group consisting of metal mats, cloths and nets, and a thermoplastic resin or a composition thereof. In this method, the thin-walled article is inserted into a mold of an injection molding machine in advance, and the thermoplastic resin or its composition is heated to a temperature higher than the melting point or softening point of the thermoplastic resin, but within a temperature range where the thermoplastic resin does not deteriorate. A method for manufacturing an electromagnetic wave shielding casing, characterized in that injection molding is performed on the inner and/or outer surface of the thin-walled object.