JPH0322904B2 - - Google Patents

Description

[Detailed description of the invention]

[] Object of the Invention The present invention relates to a flame-retardant resin composition. More specifically, (A) a polymer whose main component is vinyl chloride;
(B) Chlorinated polyethylene, (C) conductive carbon black, and (D) powdered, fibrous and/or aluminum-based alloys.
or flakes, (E) a halogen-containing organic compound, (F) antimony oxide, and (G) a hydrated inorganic substance. The purpose of the present invention is to provide a flame-retardant resin composition that is not only lighter in weight than those made by other manufacturers and has excellent electromagnetic wave shielding properties, but also has good processability and moldability. . [] Background of the Invention The sources of electromagnetic radiation are increasing with the advancement of industry and the standardization of home life. Therefore, leakage of electromagnetic waves has negative effects such as dangerous harm to the human body and malfunction of ICs related to electronic devices, 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 have come to be used in automatic control devices for various devices including engines, as well as speedometers, tachometers, and the like. Furthermore, they are now equipped with microcomputers. In addition, 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. In general, since metal has the property of absorbing or reflecting electromagnetic waves, it is effectively used as an electromagnetic wave shielding material for microwave ovens and various communication devices. For the same purpose, plastics are also coated with metal by thermal spraying, vapor deposition, painting, plating, etc. Furthermore, materials obtained by incorporating relatively large amounts of additives such as carbon powder and metal powder into plastics have also been used. However, the methods of using metal as a material or the method of treating plastic with metal thermal spraying have disadvantages 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 you mix a large amount,
Although this method is effective, it has the drawback that the mechanical strength of the resulting molded product is significantly reduced. Furthermore, for plastic molded products whose inner surfaces are coated with metal spraying or conductive coating for the purpose of shielding electromagnetic waves, the metal spray coating or conductive coating may peel off or become fragmented due to impact from falling balls from the outside. If such items fall, it may damage the internal electronic circuits or cause a fire. Furthermore, in electronic equipment such as office equipment, flame retardant housings are required from the viewpoint of fire safety. As described above, there is a need for a resin composition that does not cause peeling or destruction of the surface layer due to impact, is flame retardant, has excellent processability, and has electromagnetic wave shielding ability. [] Constitution of the Invention Based on the above, the present inventors have set out to obtain a synthetic resin composition that does not have these drawbacks, has excellent electromagnetic wave shielding performance, and has good flame retardancy. As a result of various searches, (A) "Polymer mainly composed of vinyl chloride with a degree of polymerization of 400 to 4000" (hereinafter referred to as "vinyl chloride resin"), (B) Amorphous or crystalline chlorine-containing polymer Rate is 20-50
% by weight of chlorinated polyethylene, (C) conductive carbon black, (D) "powder, fiber and/or flake of aluminum or aluminum-based alloy" (hereinafter referred to as "aluminum powder") (E) halogen-containing organic compound, (F) antimony oxide, and (G) hydrated inorganic substance, including vinyl chloride resin, chlorinated polyethylene, aluminum powder, etc. The proportion of conductive carbon black in the total is 1 to 1% by volume for chlorinated polyethylene, 5 to 50% by volume for conductive carbon black, and 5 to 50% by volume for aluminum powder, etc.
However, the total amount of conductive carbon black and aluminum powder is 10 to 60
The proportion of chlorinated polyethylene in the total amount of vinyl chloride resin and chlorinated polyethylene is at most 40% by volume, and the total amount of vinyl chloride resin and chlorinated polyethylene is 100% by volume.
The proportion of the halogen-containing organic compound and antimony oxide to parts by weight is at least 5 parts by weight each, but their total amount is at most 50 parts by weight, and the water-containing inorganic substance is at most 40 parts by weight. A flame retardant composition containing at least 5 parts by weight of a water-containing inorganic substance per 100 parts by weight of conductive carbon black not only has excellent flame retardancy but also has good electromagnetic wave shielding performance. We have discovered that this is a resin composition that has various effects (characteristics), and have arrived at the present invention. [] Effects of the Invention In particular, the present invention is characterized by the selection of aluminum among various metals. Aluminum has a low specific gravity compared to other metals, so it is not only easy to mix uniformly with vinyl chloride resin and polyethylene chloride, but also because it is highly flexible, it is difficult to mix it with a mixing machine during mixing and molding. It also causes less damage to molds, etc., and has excellent workability. Furthermore, unlike iron, it is not attacked by moisture in the air. That is, the flame-retardant resin composition obtained by the present invention not only has extremely excellent electromagnetic wave shielding performance, but also has the following effects (characteristics). (1) It is lightweight. (2) Mechanical strength such as bending strength is good. (3) It has excellent moldability, so it can be easily processed and molded into any shape. (4) Secondary processing costs required for electromagnetic wave shielding treatments (for example, metal spraying, conductive coating, plating, etc.) are no longer required, resulting in significant cost reductions. (5) Due to its excellent thermal conductivity, when used in the housing of electronic equipment, internal heat dissipation efficiency improves. (6) Because it has conductivity, it is effective against equipment failure due to static electricity (has a static electricity shielding effect). (7) Since it is flame retardant, it is possible to maintain safety even against abnormal currents in internal equipment. The flame-retardant resin composition 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 fax machines, printers, word processors, etc. (2) Internal parts of housings for electrical and electronic equipment such as consumer electronics such as televisions and videos, electronic equipment, computers, and communication equipment; (3) Housing materials for the various measuring instruments (speedometers, etc.) in automobiles, housing materials for automatic control devices such as engines, housing materials for microcomputers, telephones, televisions, radios, etc. installed in automobiles, and even electricity. Furnace tube cover for wiring cover [] Detailed description of the invention (A) Vinyl chloride resin The vinyl chloride resin used in the present invention contains vinyl chloride homopolymer and vinyl chloride in an amount of at most 50% by weight (preferably The degree of polymerization of this vinyl chloride resin, which is a copolymer with a compound having at least one double bond that can be copolymerized with vinyl chloride (45% by weight or less), is 400 to 4000,
400-2500 is preferred, particularly 400-1500. Representative examples of compounds having at least one double bond include vinylidene chloride, ethylene, propylene, vinyl acetate, acrylic acid and methacrylic acid and their esters, maleic acid and their esters, and acrylonitrile. These vinyl chloride-based polymers are obtained by homopolymerizing or copolymerizing vinyl chloride alone or vinyl chloride and the above-mentioned vinyl compound in the presence of a free radical catalyst, and the manufacturing method is widely used. It is used in many fields. (B) Chlorinated polyethylene The chlorinated polyethylene used in the present invention can be obtained by chlorinating polyethylene powder or particles in an aqueous suspension or by chlorinating polyethylene dissolved in an organic solvent. (preferably those obtained by chlorination in aqueous suspension). In general, amorphous or crystalline chlorinated polyethylenes having a chlorine content of 20 to 50% by weight are preferred, and amorphous and chlorinated polyethylenes having a chlorine content of 25 to 45% by weight are particularly preferred. The polyethylene is obtained by homopolymerizing ethylene or copolymerizing ethylene with at most 10% by weight of α-olefin (generally having at most 6 carbon atoms). Its density is generally 0.910-0.970/cm ³ . or,
Its molecular weight is 50,000 to 700,000. The polyethylene used to produce this chlorinated polyethylene is ethylene alone, ethylene and propylene, or ethylene and the above α
- olefin using a so-called Ziegler catalyst or a Phillips catalyst. Ziegler's catalyst is a transition metal compound (e.g., a halogen-containing compound of titanium) or the transition metal compound on a carrier (e.g., a magnesium-containing compound, obtained by treating the magnesium-containing compound with an electron-donating organic compound). It is obtained by supporting a so-called carrier-supported solid catalyst component and an organoaluminum compound. Phillips catalysts are carrier-supported catalysts obtained by supporting chromium or molybdenum oxides or compounds of these oxides and zirconium on carriers (e.g., silica, silica-alumina), or the carrier-supported catalysts. It is obtained from organometallic compounds. The above catalysts are merely typical Ziegler catalysts and Phillips catalysts, and other known catalysts may also be used. The method for producing this copolymer is also a well-known method. (C) Carbon Black Furthermore, the conductive carbon black used in the present invention generally has a specific surface area of 20% as measured by low-temperature nitrogen adsorption method and BET method.
~1800m ² /g and pore volume is 30 ~
Measured by mercury intrusion method in the range of 7500 Å
1.5~4.0cc/g, especially when the specific surface area is 600~
1200m ² /g is effective. Examples of the carbon black include channel black, acetylene black, and carbon black produced by the furnace black method. Regarding these carbon blacks, please refer to “Carbon Black Handbook” edited by Carbon Black Association (published by Tosho Publishing Co., Ltd. in 1972),
Rubber Digest Co., Ltd., “Handbook, Rubber/Plastic Compounded Chemicals” (Rubber Digest Co., Ltd., published in 1971), “Synthetic Rubber Handbook”
Their manufacturing methods and physical properties are well known. (D) Aluminum powder, etc. In addition, the aluminum powder, etc. used in the present invention includes powder, fibrous, and flake materials of aluminum or aluminum alloy. Its average size is generally between 250 and 20 meters. Further, the diameter of the fibrous material is generally 0.0020 to 0.20 mm, and a length of 10 mm or less is preferable because it is easy to process. Further, the flakes can be of any shape such as circular, square, rectangular, or rectangular with a cross-sectional area of 0.1 x 0.1 mm to 5 x 5 mm, but especially the thickness
Desirably 0.1mm or less. Among them, about 1
Rectangular shape with a cross-sectional area of ×1 mm and a thickness of approximately 0.03
mm has good dispersibility. Aluminum flakes have good dispersibility in the impact-resistant resin, and unlike fibrous materials, they do not tangle with themselves to form beads. In addition, there is a strong tendency to mix it along the flow direction of the impact-resistant resin during molding, and when mixed in the same amount, it not only has good conductivity but also improves the flexural modulus. Above all,
A flake-like material having a surface area of 1 mm x 1 mm is most preferred from the viewpoint of dispersibility. These powdery, fibrous, or flaky 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 Further, the aluminum content in the aluminum alloy is usually 80% by weight or more. The above vinyl chloride resins. By uniformly blending chlorinated polyethylene, aluminum powder, etc., and conductive carbon black, this composition not only has excellent electromagnetic wave shielding performance and good mechanical strength, but also good moldability. However, the flame retardance is not satisfactory. Furthermore, by incorporating the following halogen-containing organic compound and/or antimony oxide, it is possible to obtain a composition with extremely excellent flame retardancy. (E) Halogen-containing organic compound The halogen-containing organic compound used in the present invention is widely known as a flame retardant. Typical examples include tetrachlorophthalic anhydride, chlorinated paraffin, chlorinated bisphenol A, brominated bisphenol S, chlorinated diphenyl, brominated diphenyl, chlorinated naphthalene, tris (β-chloroethyl) phosphate, and tris (dibromo butyl) phosphate. (F) Antimony oxide Further, the antimony oxide used in the present invention 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." (G) Water-containing inorganic substance The water-containing inorganic substance used in the present invention contains 10 to 80% by weight of bound water and has a true specific gravity of 1.0 to 5.0. Typical examples of hydrated inorganic substances are hydrates of metals of Groups A, B, and B of the periodic table and salts containing these metals. The hydrated inorganic substances include magnesium hydroxide, calcium hydroxide, aluminum hydroxide (Al ₂ O ₃ · nH ₂ O), hydrated gypsum, kaholin clay, calcium carbonate, hydrotalcite, basic magnesium carbonate, and boric acid. Examples include compounds that have water in their molecules, such as magnesium and precipitated barium sulfate. These water-containing inorganic substances are poorly soluble in water, and 100
The solubility of cc in water at a temperature of 20℃ is
Generally, the amount is 10 g or less, preferably 1 g or less, and particularly preferably 0.1 g or less. Suitable hydrous inorganic substances include aluminum hydroxide,
Hydrated gypsum, magnesium hydroxide, calcium carbonate, basic magnesium carbonate, precipitated magnesium sulfate and magnesium silicate (MgO.
SiO ₂ ). Regarding these water-containing inorganic substances, please refer to “Handbook” edited by Rubber Digest Co., Ltd.
Rubber/Plastic Compound Chemicals” (Rubber Digest Co., Ltd., published in 1972) pp. 221-253
Each page describes their manufacturing method, physical properties, trade name, etc., and is well known. (H) Blending ratio In the composition of the present invention, vinyl chloride resin,
The proportion of chlorinated polyethylene in the total (total amount) of chlorinated polyethylene, aluminum powder, etc., and conductive carbon black is 1 to 25% by volume, preferably 2 to 25% by volume, particularly 5 to 25% by volume. 20% by volume is preferred. If the blending ratio of chlorinated polyethylene in the total amount is less than 1% by volume, the flame retardancy of the resulting composition will be poor, and it will be difficult to obtain uniform dispersion with the flame retardant described below, resulting in poor retardancy. The combustion effect cannot be exerted uniformly. On the other hand, if it exceeds 25% by volume, it is not preferable because the resulting composition will have lower strengths such as stiffness and flexural modulus. In addition, the blending ratio of chlorinated polyethylene in the total amount (sum) of vinyl chloride resin and chlorinated polyethylene is at most 40% by volume, preferably 5 to 40% by volume, especially 10 to 35% by volume.
Volume % is preferred. If the proportion of chlorinated polyethylene in the total amount exceeds 40% by volume, the strength of the vinyl chloride resin, such as stiffness and flexural modulus, will decrease, and when used as a housing, it will have the disadvantage of being "soft". will arise. Furthermore, the content (blending ratio) of aluminum powder in the composition obtained by the present invention is 5 to 50% by volume, and the content of conductive carbon black is 5 to 50% by volume. be. Furthermore, the total amount of both in the composition is 10 to 60% by volume. An important point of the present invention is that aluminum or aluminum alloy powder, fibers, or flakes and conductive carbon black are used together in the composition, and furthermore, the sum of the two is 10
~60% by volume. In particular, it is desirable that the sum of these is 20 to 50% by volume. Further, it is preferable that the capacitance ratio of aluminum powder or the like to conductive carbon black is in the range of 2.5:1 to 1:2.5. In particular, by mixing conductive carbon black, which has a shielding effect in the low frequency range (MHz), and aluminum flakes, which has an electromagnetic wave shielding effect in the high frequency range (KHz), the shielding effect can be achieved over a wider frequency range. In addition to showing, when used alone,
It has been discovered that even in areas where there is little effect, a significant shielding effect can be achieved by using both in combination. Although the reason for this remarkable effect is not clear, it is presumed that electromagnetic wave energy reflected or absorbed by aluminum powder or the like is grounded through the conductive carbon black. A result that supports this reason is that the conductivity of the composition of the present invention is significantly improved by the combined use of conductive carbon black. If the sum of aluminum powder, etc. and conductive carbon black in the composition obtained by the present invention is less than 10% by volume, the shielding effect, particularly in the low frequency range, cannot be sufficiently exhibited. On the other hand, if it exceeds 60% by volume, the moldability of the composition decreases, which is not preferable. Furthermore, the blending ratio of the halogen-containing organic compound and antimony oxide to 100 parts by weight of the total amount of vinyl chloride resin and chlorinated polyethylene is at least 5 parts by weight each. In addition, the total amount thereof is at most 50 parts by weight, and the total amount is preferably 10 to 45 parts by weight.
Particularly preferred is 15 to 45 parts by weight. The blending ratio of antimony oxide to the amount of halogen element in 100 parts by weight of a halogen-containing organic compound is generally 100 to 600 parts by weight, preferably 100 to 400 parts by weight, and particularly 150 parts by weight from the viewpoint of flame retardancy and bleedability. ~400 parts by weight is preferred. The important point of the present invention is that in addition to the usual flame retardant formulation consisting of a normal flame retardant (halogen-containing organic compound and antimony oxide), it has good moldability and high flame retardancy (V- In order to impart O), at most 50 parts by weight of a water-containing inorganic substance is blended with respect to 100 parts by weight of the total amount of vinyl chloride resin and chlorinated polyethylene, and in particular, 45 parts by weight or less (addition )It is to be. In addition, at least 5 parts by weight, preferably 10 parts by weight or more, preferably 20 parts by weight or more of a hydrous inorganic substance is added to 100 parts by weight of the conductive carbon black. It is not possible to obtain a composition that has flame retardancy, mechanical properties, and moldability. In producing the composition of the present invention, vinyl chloride resin, chlorinated polyethylene, conductive carbon black, aluminum powder, etc.
Each of the halogen-containing organic compound, antimony oxide, and hydrated inorganic substance may be used alone, or two or more types may be used in combination. (J) Production of composition, production of molded article The composition of the present invention can be produced by dry blending using a mixer such as a Henschel mixer commonly used in the vinyl chloride resin industry. It can often be obtained by melt-kneading using mixers such as Banbury mixers, kneaders, roll mills and screw extruders. At this time, a uniform composition can be obtained by dry blending in advance and melt-kneading the resulting composition (mixture). In particular, it is preferable to use the vinyl chloride resin in the form of powder because it can be mixed more uniformly. In this case, the mixture is generally melt-kneaded and then formed into pellets, which are then subjected to the forming described later. When producing the composition of the present invention, stabilizers against oxygen and heat, metal deterioration inhibitors commonly used in the field of vinyl chloride resins,
Plasticizers, fillers, lubricants and flame retardants may also be added. In the case of melt-kneading and molding as described above,
Both methods must be carried out at a temperature above the softening point of the vinyl chloride resin used, but if carried out at temperatures above 250°C, some of the vinyl chloride resin may undergo thermal deterioration, so this temperature It goes without saying that the following must be done. Molding methods include extrusion molding, injection molding,
and press molding methods. Furthermore, molding methods commonly used in the field of vinyl chloride resins such as stamping methods, press molding methods using extruded sheets, vacuum molding methods, etc. may also be applied. As described above, the composition of the present invention has excellent processability, so it can be molded into various shapes by the molding method described above and used in a wide variety of applications. Furthermore, the composition of the present invention may be laminated in as many layers as possible depending on the purpose, as long as the effects of the present invention are not impaired. [] Examples and Comparative Examples The present invention will be explained in more detail below using Examples. In addition, in the Examples and Comparative Examples, the volume resistivity value was determined by taking out a specimen measuring 3 cm in length and 1 cm in width from the molded product shown in Figure 1, and measuring A and B in Figure 1 (both 1 cm in width)2. Conductive silver paste was applied to both the front and back. After the paste is sufficiently dry,
The resistance value between each paste application was measured using a tester (SANWA SR-3TR, manufactured by Sanwa Denki Keiki). The volume resistivity value was expressed as (Ω·cm) by dividing the obtained value by the thickness (t). In addition, the electromagnetic wave shielding effect was measured using a sheet with a thickness of 3 mm.
A sample box measuring 10 x 10 x 30 cm was made, and a portable oscillator adjusted to a predetermined frequency (200 MHz) was placed inside the 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 oscillator were also measured in the same way when the box produced from the sheet was removed, and the ratio of the electromagnetic wave attenuation of the sample sheet was expressed as the ratio of the electrolytic strength (μV) with and without the sample box in decibels (dB). moreover,
Flame retardant: Underwriter Laboratory (UL)
Measured according to the 94 method. The vinyl chloride resin, chlorinated polyethylene, aluminum flakes, aluminum fibers, aluminum powder, conductive carbon black, and halogen-containing organic compounds, antimony oxide, and hydrated inorganic substances used as flame retardants in the Examples and Comparative Examples were It has the following shape and physical properties. [Vinyl chloride resin (homopolymer)] As a vinyl chloride homopolymer, the degree of polymerization is approximately 820.
[hereinafter referred to as "PVC(1)"] and a homopolymer with a degree of polymerization of approximately 1100 [hereinafter referred to as "PVC(2)"]
] was used. [Vinyl chloride resin (copolymer)] Vinyl chloride-vinyl acetate copolymer with a degree of polymerization of approximately 810 as a vinyl chloride copolymer [vinyl acetate content 15% by weight, hereinafter referred to as "PVC(3)"] 〕It was used. [Chlorinated polyethylene] As chlorinated polyethylene, butene-1 is 3.0
Amorphous chlorinated polyethylene [chlorine content 31.5% by weight, Mooney viscosity (ML ₁₊₄ ) 108, hereinafter referred to as "CPE(a)"] was produced. In addition, ethylene and butene-1 copolymer with a density of 0.921 g/cm ³ (MI 20 g/10 min, number of alkyl groups per 1000 carbon atoms in the main chain: 6,
Melting point: 120℃) was chlorinated by the aqueous suspension method, and the chlorine content was 40.2% by weight.
Amorphous chlorinated polyethylene (hereinafter referred to as "CPE(b)") having a Mooney viscosity (MS ₁₊₄ ) of 55 and a copolymer of ethylene and butene-1 containing 3.0% by weight of butene-1. (Density 0.940g/ ^cm3 ,
(average molecular weight approximately 100,000) is chlorinated in an aqueous suspension,
Crystalline chlorinated polyethylene (chlorine content 30.8
Weight%, residual crystal content of polyethylene 7.15% by weight, Mooney viscosity (ML ₁₊₄ ) 110, hereinafter "CPE"
(c)” was used. [Aluminum flakes] As aluminum flakes, the cross-sectional area is 1×
Square aluminum flakes (hereinafter referred to as "Al flakes") having a size of 1 mm and a thickness of 0.03 mm were used. [Aluminum Powder] As the aluminum powder, aluminum powder (hereinafter referred to as "Al powder") having a particle size of 74 to 150 microns was used. [Aluminum fiber] Aluminum fiber with a length of approximately 6 mm and a diameter of
A 65 micron aluminum fiber (hereinafter referred to as "Al fiber") was used. [Conductive carbon black] As a conductive carbon black, the average particle size is approx.
30mm Furnace Black (manufactured by Cabot Inc., product name: Vulcan XC)
−72, density approximately 1.8g/cc, surface area 200m ² /g,
Hereinafter referred to as "CB-1"] and Ketschenblak (manufactured by Akzo Hemie, Netherlands, product name)
Ketuchen black, density 1.8g/cc surface area
1195 m ² /g, hereinafter referred to as "CB-2"] was used. [Halogen-containing organic compound] As a halogen-containing organic compound, the density is 1.66.
g/ ^cm3 (molecular weight approx.
1.060, chlorine content approximately 70% by weight, hereinafter referred to as "Salt Para"
) was used. [Antimony oxide] Antimony trioxide (hereinafter referred to as "Sb ₂ O ₃ ") having a density of 5.25 g/cm ³ was used as antimony oxide. [Water-containing inorganic substance] As a water-containing inorganic substance, ultrafine magnesium silicate (density 2.75 g/cm ³ , specific surface area 20 m ² /g, particle size 0.32 to 6 microns, SiO ₂ content 62.5% by weight, MgO content 30.6 weight) %, _H2O content 4.99
% by weight (hereinafter referred to as "MgO.SiO ₂ ") was used. Examples 1 to 8, Comparative Examples 1 to 5 Vinyl chloride resin (30 parts by weight of cyoctyl phthalate and 25 parts by weight of dibenzyl phthalate as a plasticizer and 3 parts by weight per 100 parts by weight of vinyl chloride resin as a plasticizer, respectively) (by weight of tribasic lead sulfate and 1 part by weight of dichlorinated lead stearate), chlorinated polyethylene and the above mixtures, and aluminum (Al) powder such as Al flakes, Al fibers and Al powder, conductive Carbon black, a halogen-containing organic compound as a flame retardant, antimony oxide, and a water-containing inorganic substance were dry blended in advance for 5 minutes using a Henschel mixer at the mixing ratios shown in Table 1. Each of the obtained mixtures was extruded using a twin-screw extruder (diameter 30 mm) at a resin temperature of 230°C while melt-kneading to produce pellets (compositions). A test piece with a thickness of 3 mm was prepared from each of the obtained compositions (pellets) using a sheet molding machine preset at 200°C. The Izot impact strength (measured according to ASTM D-256-56, with notches) of the mixture obtained in Example 1 was 1.3 kg·cm/cm.
In addition, the tensile strength (measured according to JIS K6723) is 330Kg/ ^cm2 , and the elongation rate (JIS K-6723
(measured accordingly) was 5%. The flame retardancy test, volume resistivity value, and electromagnetic wave shielding effect of each sheet obtained as described above were measured. The results are shown in Table 2. In addition, in Comparative Example 2, it was difficult to mold the sheet.

【table】

【table】

[Table] From the results of the above Examples and Comparative Examples, it is clear that the composition obtained by the present invention not only has good electromagnetic wave shielding properties, but also has a halogen-containing organic compound,
It is clear that the flame retardance is significantly improved compared to a composition that does not contain either antimony oxide or a hydrous inorganic substance.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a specimen for measuring volume resistivity. A and B (front and back) in FIG. 1 are the surfaces coated with conductive silver paste.

Claims (1)

[Scope of Claims] 1 (A) A polymer mainly composed of vinyl chloride with a degree of polymerization of 400 to 4000, (B) Amorphous to crystalline chlorine content of 20 to 50
% by weight of chlorinated polyethylene, (C) conductive carbon black, (D) powder, fibers and/or flakes of aluminum or aluminum-based alloys, (E) halogen-containing organic compounds. , (F) antimony oxide and (G) a composition consisting of a hydrous inorganic substance, which includes a polymer mainly composed of vinyl chloride, chlorinated polyethylene, powdered material of aluminum or an alloy mainly composed of aluminum, and fibers. The proportion of carbon black, flake, and conductive carbon black is as follows:
Chlorinated polyethylene is 1 to 25% by volume, conductive carbon black is 5 to 50% by volume, and aluminum or aluminum-based alloy powders, fibers, and flakes are the sum of these. The total amount of conductive carbon black, fibrous materials, and powdery materials is 10 to 60% by volume, and the total amount of conductive carbon black is 10 to 60% by volume. The proportion of chlorinated polyethylene in the total amount of combined and chlorinated polyethylene is at most 40% by volume, and the proportion of chlorinated polyethylene in the total amount of 100 parts by weight of the polymer mainly composed of vinyl chloride and chlorinated polyethylene is The organic compound and antimony oxide contained are each at least 5 parts by weight,
their total amount is at most 50 parts by weight,
The amount of hydrated inorganic substances is at most 40 parts by weight, but not more than 100 parts by weight.
A flame-retardant resin composition in which the proportion of the water-containing inorganic material to the conductive carbon black is at least 5 parts by weight.