JPS5899788A - Shielding material for electromagnetic wave - 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 (I) OBJECTS OF THE INVENTION The present invention relates to an electromagnetic wave shielding material based on a polymer containing styrene as a main component. More specifically, (I) a first layer consisting of a polymer mainly composed of styrene and a polyoleguin modified with an unsaturated carboxylic acid or a derivative thereof, or the modified polyolefin and a polyolefin, (B) aluminum metal or Aluminum alloy materials, fibrous materials and/or flakes and rG! It relates to an electromagnetic wave shielding material formed by laminating a 141iE carbon black layer,
An object of the present invention is to provide an electromagnetic wave shielding material that not only has a high electromagnetic wave shielding property but is also lighter in weight and easier to process and mold than metal materials.

(9) Background of the Invention The sources of electromagnetic radiation are increasing with the advancement of industry and the standardization of household life. Therefore, leakage of electric waves and A-waves may cause dangerous harm to the human body and I/O in electronic equipment.
There are negative effects such as malfunction of C, which 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.

For these reasons, various methods of shielding and shielding electromagnetic waves have been adopted in recent years.

In general, metals have the property of absorbing or reflecting electromagnetic waves, so they are used effectively as shielding materials for electromagnetic waves in microwave ovens and other communication devices. Also, for the same purpose, metal spraying, steaming, painting,
It is almost impossible to apply plating etc. In addition, materials obtained by incorporating additives such as carbon powder and metal powder into plastics in relatively large amounts are also used.

However, the method of using a single metal as the material or the method of treating plastic to make it resistant to metal baths has problems such as high specific gravity, poor workability, and difficult processing methods. However, they also have disadvantages in that they require considerable expense.

-Also, regarding the method of mixing an elephant additive, if a small amount of this foil additive is mixed, the effect cannot be fully exhibited. On the other hand, if they are mixed vertically in multiple directions, the effect can be exhibited, but there is a drawback that the mechanical strength of the resulting molded product is significantly reduced.

Based on the above, the present inventors have made extensive searches to obtain a single-fat composition that has these drawbacks and has excellent electromagnetic wave shielding performance. (hereinafter referred to as ``styrenic polymer'')
A first layer consisting of a first layer consisting of is 0, O1-1.0% by weight
] 90-40 capacity, (B) "Powder, fibrous and/or flake material of aluminum metal or aluminum alloy" 5-5
0 capacity lid and (2 conductive car pumps 5~508 it 96
, and a second layer consisting of a second layer, which not only has good electromagnetic wave shielding performance, but also is an electromagnetic wave shielding material that has various characteristics (effects),
We have arrived at the present invention.

[IV) Effects of the invention That is, the electromagnetic wave shielding material obtained by the present invention not only has extremely excellent electromagnetic wave shielding performance, but also has excellent electromagnetic wave shielding performance.
It has the following effects (%).

(1) It is lightweight.

(2) Good mechanical strength such as bending strength and impact strength.

(3) Since it has excellent moldability, it can be easily processed and molded into any shape.

(4) Electromagnetic wave shielding treatment (e.g. metal spraying, painting,
The secondary processing costs required for (plating, etc.) become a concern, leading to significant cost reductions.

Furthermore, when the second layer is a sand Φ Sochi structure with a foam layer, (5) the mechanical strength is further improved.

(6) The residual stress of the molded product is extremely small, and even large molded products can be produced with low warpage and distortion.Molded products with high process precision can be obtained.

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

(1) Housing materials for office equipment such as facsimile machines, printers, word processors, etc. (2) Housing materials and internal parts for consumer and home appliances such as televisions and videos, electrical and electronic devices such as computers and communication equipment [v] Invention Detailed Description (A) Styrenic polymer The styrenic polymer used in the present invention is a styrene homopolymer (generally, the molecular weight is 50,000 to
ooo-o), 99.5 to 80 parts by weight of styrene in 05 to 20 parts by weight of copolymers with other double bond-containing organic compounds and compounds containing at least 100% styrene, and rubber-like materials mainly composed of butadiene. Examples include graft M combinations obtained by graft polymerizing parts by weight of styrene. Representative examples of the organic compounds having double bonds include ethylene, vinyl acetate, anuric maleic acid, acrylonitrile, and methyl methacrylate. Methods for producing these styrenic polymers are widely known and used in a wide variety of fields.

03) Modified polyolefin The polyolefin used to produce the modified polyolefin of the present invention includes a homopolymer of ethylene, a homopolymer of propylene, a copolymer of ethylene and propylene, ethylene and/or a copolymer of propylene with a large number of carbon atoms. - Copolymer with 7 other α-olefins (copolymerization ratio of α-olefins is at most 20% by weight)
- and copolymers of ethylene and vinyl acetate, nys-tyl acrylate, and methyl acrylate (the copolymerization ratio of vinyl compounds is required at most. The molecular type of these polyolefins is
In general, the molecular weight is from 20,000 to 1,000,000, preferably from 20,000 to 500,000, and particularly preferably from 50,000 to 300,000. Also desirable are low density and high density ethylene homopolymers, propylene homopolymers, copolymers of ethylene and propylene, and copolymers of ethylene or propylene with other α-olefins.

The modified polyolefin used in the present invention can be obtained by modifying the polyolefin described above with an unsaturated carboxylic acid or a derivative thereof.

Representative examples of unsaturated carboxylic acids and their derivatives include monobasic carboxylic acids having at most 10 carbon atoms and at least one double bond (e.g., acrylic and methacrylic acids); Dibasic carboxylic acids having at most 16 atoms and at least one double bond (eg, maleic acid) as well as anhydrides of the dibasic carboxylic acids (eg, maleic anhydride, hymic anhydride) are included. Among these unsaturated carboxylic acids or derivatives thereof, maleic acid and maleic anhydride are particularly preferred.

Modified polyolefins are generally obtained by treating polyolefins with unsaturated carboxylic acids and/or derivatives thereof in the presence of organic peroxides.

In order to produce the modified polyolefin of the present invention, any of various known production methods (eg, solution method, suspension method, melt method) can be employed.

Among these production methods, when polyolefin is modified with an unsaturated carboxylic acid or its derivative by a solution method, the polyolefin and the unsaturated carboxylic acid and/or its derivative are added to a nonpolar organic bath medium, and then a radical initiator is added. A modified polyolefin can be obtained by adding and heating at high temperature. In this case, the inorganic solvents used include hexane, hexane, benzene, toluene, xylene, chlorobenzene and tetrachloroethane. In addition, as a radical initiator, 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane, 2,5-dimethyl-2,5
-Organic peroxides such as di(tert-butylperoxy)hexyne-3 and benzoyl peroxide are included. Furthermore, the treatment temperature varies depending on the temperature of the polyolefin used, and is generally 110 to 160°C, particularly preferably 130 to 150°C.

In addition, when modifying a polyolefin with an unsaturated carboxylic acid or its derivative by a suspension method, the polyolefin and the unsaturated carboxylic acid and/or its derivative are added to a polar bath medium (generally water), and then It is obtained by adding a radical initiator and treating under high pressure at a temperature of 100° C. or higher.

When modifying polyolefin with an unsaturated carboxylic acid or its derivative by the melting method, it is often necessary to use a bath melt mixer (for example,
It can be obtained by melt-kneading a polyolefin, an unsaturated carboxylic acid and/or a derivative thereof, and the radical-generating agent described above using an extruder. The kneading temperature at this time varies depending on the type of polyolefin and radical generator used, but is in the temperature range from above the melting point of the polyolefin used to below aOO°C. In the case of polyethylene, generally 1
In the case of 20-270'C, polypropylene,
Generally, the temperature is 160 to 270°C.

(Q Powdered materials of aluminum metal, etc.) Also, "powdered materials, fibrous materials, and flakes of aluminum metal or aluminum alloy" used in the present invention.
(Hereinafter referred to as [aluminium metal powder, etc.])
Among them, the average size of the powder is generally between 250 mesh and 2 o mesh. Also,
As a fibrous material, its diameter is generally 0.0020-
0.20, and the length is preferably less than lotfrM because it is easy to process. Furthermore, as a flake-like material, the cross-sectional area is 0. I is desirable. Among these, those having a rectangular shape with a bendable turret of about IXI and a thickness of about 0.0 mm have good dispersibility. These powdered, fibrous, or flaky materials may be used alone, but by using two or more of them in combination, the effects of a small mixing ratio can be achieved in order to achieve the purpose of the present invention. This is suitable because it can be done. The aluminum content in aluminum alloys for pump racks is generally determined by the specific surface area measured by low-temperature nitrogen adsorption method and BFiT method.
0~1800rr? /f and pore volume is pore radius 30
1. Measured by mercury intrusion method in the range of ~7500A.
5'~4.000/t, especially when the specific surface area is 600
~1200 go/l is effective.

The car pump book includes channel plaque, acetylene plaque, and carbon black produced by the furnace planocou process. - Regarding these carbon blanks, please refer to the “Carbon Black Handbook” edited by the Carbon Black Association (Tosho, Publisher, 1972).
Rubber Digest Co., Ltd. - “Handbook, Rubber and Plastic Compounded Chemicals” (Rubber Digest Co., Ltd., 1972)
Their manufacturing methods and physical properties are well known, such as in the above-mentioned "Synthetic Rubber Handbook" (published in 2010) and the aforementioned "Synthetic Rubber Handbook." (11th layer) In manufacturing the electromagnetic wave shielding material of the present invention, it is necessary that the first layer on the surface causes almost no reflection of electromagnetic waves. In order to meet these requirements, it must have insulating properties and be easily molded by injection molding, vacuum molding, extrusion molding, fless molding, and stamping molding. Synthetic resins that can be molded into shapes are used.Stynone polymers are used for the reasons mentioned above.

(F) Second layer The function of the second layer is to absorb the electromagnetic waves that have entered through the first layer and convert the energy into heat, or to excite it and release it to other places as N gas. It is.

For these reasons, the content of the modified polyolefin or the modified polyolefin and the polyolefin in the second layer is preferably 90 to 40 by volume, particularly preferably -75 to 50 by volume. Further, the content of aluminum metal powder, etc. is 5 to 50 volumes, preferably 10 to 25 volumes.

Furthermore, the content of conductive carbon black is 5 to 50 vol. h, particularly preferably 10 to 25 vol. h.

When the content of the conductive carbon blank is less than 5 volumes,
Does not provide sufficient conductivity required for electromagnetic wave absorption. on the other hand,
If the volume is more than 50 cm, it is difficult to uniformly mix the modified polyolefin or the modified polyolefin and the polyolefin, and the resulting resin layer does not have enough strength for practical use, which is practically impossible.

In addition, the purpose of mixing aluminum metal powder etc. in the second layer is not only to further improve the electromagnetic wave absorption performance, but also to expect a high Mq and disturbance of electromagnetic waves on the surface of the aluminum metal powder etc. be. In order to bring out the synergistic effect of the conductive carbon black and the aluminum metal powder as described above, the content of the aluminum metal powder must be at least 6 volumes. If the capacity is less than 5, the synergistic effect with the two conductive car pumps will be poor. On the other hand, for 50 volumes or more,
Uniform mixing of modified polyolefin or modified polyolefin and polyolefin is not possible.

This second layer can be produced by molding a modified polyolefin, aluminum metal powder, etc., and a conductive carbon blank in the same manner as in the case of the first layer. However, Izui's molding method requires secondary processing from laminates, and there are problems with productivity. In particular, demand for OA equipment has increased rapidly in recent years, and molding methods have shifted to injection molding in order to improve productivity.

The electromagnetic wave shielding material of the present invention can also be produced using a multilayer injection molding method or a sandwich injection molding method. The number of housings for electronic equipment such as consumer electronics, communication equipment, and OA equipment varies widely, and the multilayer injection molding method and sand inch injection molding method described above are fully applicable to relatively large housings. be. However, the multilayer injection molding method and the sandwich injection molding method are often not applicable to these large housings from the viewpoint of strength, rigidity, dimensional stability, and the like.

When manufacturing the electromagnetic wave shielding material of the present invention used for these large molded products, in addition to modified polyolefin, aluminum metal powder, etc., and conductive carbon black, A suitable molding method is a method in which a blowing agent or a blowing agent and a blowing aid are blended and the mixture is foam injection molded. In addition, in the case of sandwich injection molding, it is suitable that this second layer is sandwiched inside.

The blowing agent used to produce the second l- of the present invention is a compound that does not decompose during the production of the composition, but decomposes at temperatures below the temperature at which the polyolefin used undergoes thermal decomposition. The decomposition temperature is generally 160-2
Preferably, the temperature is 50°C, and 9% iso to 240°C. Foaming agents are generally used as foaming agents for olefin resins, and are broadly classified into inorganic, organic, and organic types. Typical examples of inorganic foaming agents include sodium bicarbonate, copper carbonate, potassium magnesium carbonate, magnesium carbonate, lead carbonate, iron carbonate, and carbon hydroxide (li+gnezoum, throat ammonium, or Group IA). ; carbonates of metals of group IB, group IIA, group JIB, group WB or group II, and ammonium phosphate;
Inorganic ammonium salts such as ammonium bicarbonate, ammonium carbonate, ammonium polyphosphate, ammonium oxalate and mixtures of sodium nitrite and ammonium chloride may be mentioned. In addition, as an organic blowing agent,
N.

N'-dinitrosopentamethylenetetramine and N,
Nitroso compounds such as N'-dimethyl-N,N'-dinitrosoterephthalamide, azodicarbonamide,
Azo compounds such as azobisinbutyronitrile, azocyclohexylnitrile, diazoaminobenzene and barium azodicarboxy-benzene sulfoterehydrazide and its 'ass, 7'm: /u2
/L-oney -3,3-277,o.

hydrazide and p,p'-L-oxybis(benzenesulfonylhydrazide) and sulponylhydrazide
Examples include qt' compounds and P-') luenesulfonyla, cyto, and -4,4-diphenyldisulfonylazitoca. ' Moreover, the blowing aid can not only lower the decomposition temperature of the blowing agent, but also change the decomposition rate of the blowing agent.
This is advantageous because the range of molding conditions can be widened. These blowing aids cannot be generally specified because they vary depending on the type of blowing agent used, but include tribasic lead sulfate, zinc stearate, salicylic acid, phthalic acid, boric acid, urea, etc. Examples include resins, etc. When these foaming aids are used, suitable foaming aids for the foaming agent used are widely known.

The blending ratio of the blowing agent to 100 parts by weight of polyolefin is 0.001 to 20.0 parts by weight, particularly 0.02 to 1.0 parts by weight.
0.0 part by weight is desirable. In addition, when using a foaming aid, the proportion of the foaming aid in the foam layer should be at most 1.
It is 0% by weight.

In producing this second lil, the modified polyolefin may be mixed with an aluminum metal powder, or the modified polyolefin and the polyolefin may be mixed in advance and the resulting composition may be mixed with an aluminum metal powder. It may be mixed with other things. Furthermore, without mixing the modified polyolefin and the polyolefin in advance, they may be mixed with aluminum metal powder or the like three times at the same time. The reason for using the modified polyolefin in this second layer is not only to make the dispersion of aluminum metal powder, etc. in the second layer uniform (
This is to improve, for example, mechanical strength (for example, bending strength) by improving compatibility and adhesion with aluminum metal powder and the like. For this reason, whether only modified polyolefins are used (no polyolefins are used) or when modified polyolefins and polyolefins are used together, the amount of unsaturated carboxylic acid and/or its derivatives contained therein is generally controlled. is 001-1.2% by weight, especially 002-10
Weight percent is preferred. The unique feature of the present invention is that aluminum metal powder and conductive carbon black are used in combination in the second layer, and the total volume of the two is 10 to 60. Especially these! The sum of 25 to 50 is desirable. In addition, the capacity ratio of aluminum metal powder etc. and the conductive carbon blank is 2.5:1 to 1:25.
A range of is suitable. By mixing conductive carbon black, which has a shielding effect especially in the high frequency range (MHz), and aluminum metal flakes, which has an electromagnetic wave shielding effect in the low frequency range (Kl(z)), the shielding effect can be achieved over a wider frequency range. They not only showed that, but they also found that a combination of both produces a remarkable shielding effect even in areas where it would have little effect when used alone.The reason for this remarkable effect is as follows. Although it is not clear, it is presumed that the electromagnetic wave energy reflected or absorbed by the aluminum gold oval powder is grounded through the conductive carbon blank. By using carbon black in combination, the electrical conductivity of the second layer of the present invention can be significantly improved.

Second in this invention! If the sum of the aluminum metal powder and the conductive carbon black is less than 10 capacitances, the shielding effect, especially in the low wave region, cannot be sufficiently exhibited. On the other hand, if the volume is 60 or more, the moldability of the composition deteriorates, which is not preferable.

(Q) The method for producing the first layer and the second layer, as well as the method for producing the electromagnetic shielding material, and the method for producing the second layer of the present invention. Additional additives such as stabilizers, metal deterioration inhibitors, fillers, lubricants and flame retardants may be added.

Furthermore, when producing the first layer, the above-mentioned additives commonly used in the field of styrenic polymers may be further added.

Further, the mixture of each layer of the present invention may be blended using a four-driller mixer such as a Henschel mixer commonly used in the polyolefin industry, a Banbury mixer, a kneader, a roll mill, and a screw extruder. It can be obtained by melt-kneading using a mixer. At this time, a homogeneous composition can be obtained by triblending in advance and melt-kneading the resulting composition (mixture).

This first mixture is generally melted and kneaded, then formed into a pellet-like product and subjected to the forming described later.

In the case of melt-kneading and molding as described above, unless the process is carried out at a temperature higher than the softening point of the modified polyolefin and polyolefin used, thermal deterioration of Refy 7 and a part of the polyolefin in the modified polyolefin may occur. Therefore, it is natural that the process must be carried out at a temperature below this temperature.

To mold the first and second layers, any molding blade or method commonly used in the field of bows and fins can be applied. The first layer and the second layer can also be manufactured separately by extrusion, injection molding and press molding.

- In producing the electromagnetic wave shielding material (laminate) of the present invention, there may be mentioned a method in which each layer produced in advance is stacked and pressed. It should be noted that the lamination temperature is sufficient to be close to the melting point of the modified polyolefin or modified polyolefin and polyolefin used. Since modified polyolefin is used for the first and second layers, no special adhesive is required, but in order to obtain better contact strength,
For this reason, it is perfectly acceptable to use an N-contact agent or an adhesive film between the first layer and the second layer.

Further, the first layer and the second layer can be simultaneously produced as a laminate by applying a coextrusion molding method, for example. Furthermore, it can also be molded using a two-layer injection molding machine.

The laminate prepared as above can be used as an electromagnetic shielding material! 1. Use 3. The laminate obtained by these methods is further molded into any shape by applying commonly used molding methods such as stamping, press molding, and vacuum forming. It is also possible.

It goes without saying that even if the second layer of the electromagnetic wave shielding material of the present invention is made of a foamed layer, the magnetic wave shielding properties are not affected. The reason for this is that the stain magnetic wave shielding properties are determined by the content of aluminum metal powder and the like and conductive carbon black contained in the foam layer.

The electromagnetic wave shielding material of the present invention obtained in this way has excellent workability, so it can be molded into various shapes and used in many ways.

Furthermore, although the electromagnetic wave shielding material of the present invention is composed of two layers as described above, it may be laminated in as many layers as possible depending on the purpose and as long as the effect of the present invention is not impaired.

(Capital)-Examples and Comparative Examples' The present invention will now be explained in more detail with reference to Examples.

In the Examples and Comparisons, the melt index (hereinafter referred to as [M, LJ)] is JISK-676.
0, the temperature is 190°C and the load is 2. -16
Measured under the condition of Kg. In addition, the Melt Puffer Flow Index (hereinafter referred to as "MFIJ") is based on JIS K-67.
58, the temperature is 230°C and the load is 2. t
a Measured under T14 conditions. However, the volume resistivity test was carried out using a resistance meter (manufactured by Takuda Riken Co., Ltd., product name "Digital Multimeter TR-6856"), using a sample with a thickness of 2 mm, in an atmosphere of 25 degrees Celsius and humidity 60 degrees Celsius. The resistance of the specimen was measured below and calculated according to the formula below.

Here, S is the electrode area of the specific resistivity measurement electrode, and R
is the resistance value of the specimen, and t represents the thickness of the specimen. Furthermore, to measure the shielding effect of magnetic waves, a sample box of 10xlOx30crn was made using a sheet with a thickness of 3-.
A portable oscillator is installed in the box at a predetermined frequency (600, M
Hz). This box was placed in an anechoic chamber, and the radio waves emitted from the oscillator inside the box were measured using a receiving antenna using a microwave power meter after passing through a detector. The radio waves from the oscillator were measured in the same manner without the box manufactured from the sheet, and the ratio of the electric field strength depending on the presence or absence of the sample box was expressed in decibels (dB) and was taken as the electromagnetic wave attenuation of the sample sheet.

The mixtures used in producing the mixtures of Examples and Comparative Examples are shown below [Modified polyethylene] □ High-density polyethylene (density 0.9 aof/C
, Il, M.

1, 8.1 V710 min) 100 parts by weight, 1 part by weight of 2,5-dimethyl-2,5-di(butylperoxy)hexane (as an organic peroxide) and maleic anhydride. Tri-blending was performed in advance for 5 minutes using a Henschel mixer. The resulting mixture was melt-kneaded using an extruder (diameter: 401 m, resin temperature: 200°C) using sound, while melt-kneading it into modified polyethylene (hereinafter referred to as [modified PE]).
J and U) were created. The content of maleic anhydride in this modified pE was 0.6% by weight (modified pE). Propylene] Polypropylene (density "0.900 f / (, dl
) was treated with anhydrous maleic acid under the same conditions as modified PE, except that modified polypropylene (hereinafter referred to as [modified P,
PJ) was created. The content of maleic anhydride in this modified pp was 0.6 ml.

[Conductive carbon black]

As conductive carbon black, furnace black having an average particle size of about 30 millimeters [manufactured by Cabo Soto, USA, trade name: Vulean xa-y2. Density 1.8 f 100. , surface area 220d/f, hereinafter "
O, B, J] were used.

[Aluminum flakes] −Aluminum
As a flake, the cross section is 1x1, the thickness is 0, -03
Flare-shaped aluminum (r r4
4 flakes) was used.

[Aluminum powder] Aluminum powder (hereinafter referred to as "A! powder") having a particle size of 74 to 15-0 microns was used as the aluminum powder.

- [Aluminum fiber] - As the aluminum fiber, Narminilam fiber (hereinafter referred to as "M fiber") having a length of about 6 mm and a diameter of 65 microns was used.

Examples 1 to 8, Comparative Examples 1 to 6 [Production of first layer] 8.1 parts by weight of styrene-butadiene random copolymer rubber [styrene content 25.3% by weight, Mooney viscosity (M
ll, +4)25] was graft-polymerized with 92% by weight of styrene, and the melt flow index (JIS
K-, 6870, an impact-resistant polystyrene (hereinafter referred to as [ITP 8J]) having a resistance of 13.0 t/10 min (measured at a temperature of 190° C. and a load of xo kg) was produced.

Using an extruder (diameter: 40mm) equipped with a T-die set to a thickness of 3mm, a sheet having a thickness of 3m and a width of asown was produced.

[(B) Production of second layer]

Modified PP, AL flakes, M fiber, U powder and 0, B
and were tri-blended in advance for 5 minutes using a Henschel mixer (volume ratio 11%) in the blending amounts shown in Table 1 so that the mixture was uniform. A sheet having a thickness of 3 ml (width 350 mm) was prepared from each of the mixed mixtures according to the same method as in (4) in Table 1.

[((jl Manufacture of laminate)] The thickness of each of the first layer and second layer sheets obtained by the above (A) and (B) is 6 + 1111
1. Pass it between rolls whose temperature is controlled at 180℃ and bond both layers to a thickness of 5-8111111 and a width of 3.
A sheet (laminate) of 50 colors was manufactured.

Examples 9 to 11 ゛ Except that the same amount (70%) of modified PR was used instead of the modified PP used in Example 2 (13), the mixture of A1. flakes and O, B, ratio),
Similarly to Example 2-(B), a mixture [pellets, hereinafter "
Mixture (1)] was prepared (Example 9).

In place of the HIP S used in Example 1 (→), 75 parts by weight of HIP S and 25 parts by weight of HfF4 were used.
A mixture (pellets, hereinafter referred to as "mixture (2)") was produced by mixing the styrene-butadiene random copolymer rubber used in producing (Example 10).

Mixture 1 of HIP S produced in Example 10 (A) and styrene-butadiene random copolymer rubber
00 parts by weight, polyethylene with a molecular violet of about 200,000 (density o
, 9s5t/crl) (chlorine content 35.1% by weight)7
．． 5 parts by weight, 100 parts by weight of decapromonopisphenyl ether and 5.0 parts by weight of antimony trioxide were mixed to produce a mixture [hereinafter referred to as "mixture (3)"]. (Example 11).

Example 2 (H used in producing the first layer of Shu)
Pellets of I'PS and pellets of mixture (1) obtained as described above (Example 9, pellets of mixture (2) produced as described above and pellets of mixture (13) of Example 2)
Pellets of the mixture formed when producing the second layer of (Example 10) as well as the mixture produced as described above (
The pellets of 3) and the pellets of the mixture used in producing the second layer of (B) of Example 2 (Example 11) were each made using a two-layer injection portal machine to an average thickness of 4. Song, depth 100, radius 120111111 and length 250
-A rectangular box-shaped object was injection molded. In addition, each box-like object is a laminate consisting of a first layer as an outer layer and a second layer containing M flakes, O, and B as an inner layer.

A volume resistivity test and an electromagnetic wave shielding effect measurement of each of the laminates obtained as described above were performed. The results are shown in Table 2.

Table 2

Claims (1)

[Scope of Claims] and (6) (4) A polyolefin modified with an unsulfated carboxylic acid or a derivative thereof, or the modified polyolefin and a polyolefin [provided that the unsaturated carboxylic acid and/or the unsaturated carboxylic acid in (A) The content of its derivatives is 0
．． 1 to 1.0% by weight] 90 to 40 by volume; (B) aluminum metal or aluminum alloy powder, fibrous, and/or flake 5 to 5;
0 volume lid - (0) 4' sex car 5-50 volume It%
An electromagnetic wave shielding material formed by laminating a second layer consisting of and.