JPS58191751A - Shock-resistant resin composition - Google Patents

Abstract

PURPOSE:The titled composition that is made by adding a powder or fibrous material of aluminum or its alloy to a shock-resistant resin containing chlorinated polyethylene and its graft product, thus showing high shielding from electromagnetic waves with light weight and facilitating processing and molding. CONSTITUTION:(A) A shock-resistant resin consisting of (i) an amorphous chlorinated polyethylene, preferably of 25-45wt% chlorine content, (ii) a polymer resulting from grafting styrene and other vinyl compounds such as ancrylonitrile onto a chlorinated polyethylene and (iii) a copolymer from styrene and another monomer where (i) and (ii) total to 5-40wt%, is combined with (B) a powder or fibrous material and/or flakes of aluminum or an alloy mainly containing the same so that the content of component A reaches 40-90wt%, preferably 45-80vol%. The combination of component B different in shape develops good effect despite less amounts of mixing.

Description

DETAILED DESCRIPTION OF THE INVENTION q] Object of the Invention The present invention relates to an impact-resistant resin composition. More specifically, (A) (1) chlorinated polyethylene, (2) a graft copolymer obtained by graft copolymerizing styrene and at least one other vinyl compound to chlorinated polyethylene, and (3) styrene and An impact-resistant resin containing at least one copolymer with at least one other vinyl compound (however, depending on the proportion of chlorinated polyethylene and styrene and at least one other vinyl compound in the impact-resistant resin) The present invention relates to an impact-resistant resin composition comprising graft copolymerized gold powder, fibers and/or flakes,
The object of the present invention is to provide an impact-resistant resin composition that not only has high electromagnetic wave shielding properties, but is also lighter than metal compositions and is easier to process and mold.

■] Background of the Invention The sources of electromagnetic radiation are increasing due to the advancement of industry and the standard of household life. 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, microcomputers were also installed. 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 radiation 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. 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 have also been 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.

■ Structure of the Invention Based on the above, the present inventors conducted various searches to obtain a synthetic resin composition that does not have these drawbacks and has excellent electromagnetic wave shielding performance, and as a result, (A) ( 1) chlorinated polyethylene, (2) a graft copolymer obtained by graft copolymerizing styrene and at least one other vinyl compound to chlorinated polyethylene, and (8) styrene and at least one other vinyl compound. An impact-resistant resin containing at least one of the copolymers of ) and (B) "powder, fibrous and/or flake of aluminum or an aluminum-based alloy" (hereinafter referred to as "aluminum powder"). etc.), and the proportion of the impact-resistant resin in the composition is 50 to 95 volumes, and the impact-resistant resin composition has good electromagnetic wave shielding performance. In addition, they have discovered that the resin composition has various characteristics (effects), and have arrived at the present invention.

Jun Effects of the Invention Particularly, 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 impact-resistant resin, but it is also highly flexible, so it is difficult to mix with mixers and molds during mixing and molding. It is less likely to damage other materials and has excellent workability. moreover,
Unlike iron, it is not attacked by moisture in the air.

That is, the impact-resistant 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) Good mechanical strength such as bending strength and continuous impact strength.

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

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

(5) Since it has excellent thermal conductivity, when used in the housing of electronic equipment, the internal heat dissipation efficiency is improved.

(6) Flame retardancy can be easily imparted.

The impact-resistant resin composition obtained by the present invention not only has extremely good electromagnetic wave shielding performance but also has the above-mentioned outstanding 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) Consumer home appliances and electronic equipment such as televisions and videos,
Housing machine internal parts for electrical and electronic equipment such as electronic computers and communication equipment; (3) Housing materials for the various measuring instruments (speedometers, etc.) in automobiles; housing materials for automatic control machines such as engines;
Micro-O computers installed in cars, telephones,
Heightening materials for televisions, radios, etc., as well as covers for furnace tubes for electric wiring covers, ■ Detailed Description of the Invention (A) Impact Resistant Resin The impact resistant resin used in the present invention is made of at least chlorinated polyethylene and styrene. The total amount of chlorinated polyethylene graft copolymerized with one kind of other vinyl compound is 5 to 40% by weight (preferably 1% by weight).
(0 to 40% by weight, preferably 15 to 35% by weight).

The impact-resistant resin contains chlorinated polyethylene, a copolymer of styrene and at least one other vinyl compound (e.g., acrylonitrile, methyl methacrylate), and/or a graft copolymer of styrene and at least one other vinyl compound. It is made of chlorinated polyethylene.

The impact-resistant resin of the present invention is a composition obtained by mixing chlorinated polyethylene and the above copolymer, and a composition obtained by graft copolymerizing styrene and at least one other vinyl compound to chlorinated polyethylene. Graft copolymer and a graft copolymer obtained by graft copolymerizing a small amount of styrene and at least one other vinyl compound to previously chlorinated polyethylene, which is obtained by further mixing the above-mentioned copolymer. It is a composition. When using a composition among the impact-resistant resins of the present invention, a composition obtained by mixing the constituent components in advance may be used, and when producing the composition that is the final product of the present invention. These may be mixed. In the present invention, among the above-mentioned compositions or graft copolymers as impact-resistant resins,
Regardless of which method is used, it is important to blend the graft copolymerized and graft copolymerized chlorinated polyethylene in the impact-resistant resin of the final product composition so that it is in the composition ratio described above. It is.

Chlorinated polyethylene used in the production of impact-resistant resins is 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). Generally, amorphous or crystalline chlorinated polyethylene with a chlorine content of 20 to 50% by weight is used, and amorphous chlorinated polyethylene with a chlorine content of 25 to 45% by weight is particularly preferred.

Said 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 between 0.910 and 0.910.
97011/ec. Moreover, its molecular weight is 50,000 to 700,000.

Specific examples of impact-resistant resins used in the present invention include graft copolymerization of styrene and acrylonitrile to chlorinated polyethylene, and graft copolymerization of styrene and methyl methacrylate to chlorinated polyethylene. A blend of chlorinated polyethylene and a copolymer resin of styrene and acrylonitrile, a blend of chlorinated polyethylene and an acrylic resin, and the like can be mentioned. The acrylic resin is a polymer containing methacrylic ester or acrylic ester as a main component. Typical examples include polymers based on methyl acrylate, butyl acrylate and/or methyl methacrylate.

(B) Aluminum Powder Among the powder, fibrous and flaky materials of aluminum or aluminum alloy used in the present invention, the average size of the powder is generally 250 mm. It is between 1 and 20 meshes. In addition, the diameter of the fibrous material is generally 0.0020 to 0.20 mm,
A length of 10wJJ or less is desirable because it is easier to process.

Furthermore, as a flake-like material, the cross-sectional area is 0.1×0,
Round, square, with 5X51111 from 11111
Although any shape such as a rectangle or square can be used, it is particularly desirable to have a thickness of 0.1101 mm or less. Among these, those having a rectangular shape with a cross-sectional area of about IXIII and a thickness of about 0.03 m+ have good dispersibility. Aluminum flakes have good dispersibility in the impact-resistant resin and do not get entangled with themselves to form beads like fibrous materials. In addition, there is a strong tendency to blend along the flow direction of the impact-resistant resin during molding.
At the same mixing amount, not only the conductivity is good, but also the bending elastic modulus is improved.

In particular, flakes having a surface area of 1 m×1+w are most preferred from the viewpoint of dispersibility. These powders,
Although the fibrous material or the flake material may be used alone, it is preferable to use two or more of them in combination because the effect can be achieved with a small mixing ratio in order to achieve the object of the present invention.

In addition, the content of aluminum in aluminum alloy is
It is usually 80% by weight or more.

1) Blending ratio The blending ratio of the impact resistant resin in the composition of the present invention is 9
0 to 4o capacity chi, preferably 85 to 45 capacity chi,
Particularly suitable is 80 to 45 volumes (that is, the mixing ratio of the aluminum powder is 10 to 60 volumes, preferably 15 to 55 volumes, particularly preferably 20 to 55 volumes). If the proportion of the aluminum powder in the composition is less than 10% by volume, it will not provide sufficient conductivity necessary for absorbing electromagnetic waves. On the other hand, if the volume is 60 cm or more, it is extremely difficult to mix it uniformly with the impact-resistant resin, and even if a uniform composition is made, it does not have enough strength for practical use, so it is difficult to mix it with the impact-resistant resin. It's impossible.

(n Manufacture of composition, manufacture of molded article) To manufacture the composition of the present invention, tri-blending may be performed using a mixer such as a Henschel mixer, which is commonly used in the impact-resistant resin industry. It can be obtained by melt-kneading using a mixer such as a Banbury mixer, kneader, roll mill, or screw extruder.In this case, tri-blending is performed in advance, and the resulting composition (mixture) is melted. A homogeneous composition can be obtained by kneading.

In particular, it is preferable to use the impact-resistant resin in the form of powder because it allows for more uniform mixing.

In this case, the mixture is generally melt-kneaded, then molded into pellets, and subjected to the molding described later.

When producing the compositions of the present invention, oxygen and heat stabilizers, metal deterioration inhibitors, fillers, lubricants and flame retardants commonly used in the field of impact resistant resins may also be added. .

Both the above-mentioned melt mixing and molding must be carried out at a temperature above the softening point of the impact-resistant resin used, but if carried out at a temperature above 250°C,
Because some impact-resistant resins may undergo thermal deterioration,
It goes without saying that the process must be carried out at a temperature below this temperature.

Examples of the molding method include extrusion molding, injection molding, and press molding. Furthermore, molding methods commonly used in the field of impact-resistant 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 many ways.

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

In addition, in the examples and comparative examples, the tensile strength is AST
Measured according to MD-638.

Furthermore, the bending strength and bending modulus jdAs TMD-
790. In addition, Izotsu (Iz
od) Impact strength was measured with a notch according to ASTM D-256. In addition, the volume resistivity test is performed using a resistance meter (manufactured by Tagada Riken Co., Ltd., product name: Digital Multimeter).
TR-6856), using a test piece with a thickness of 2 cm, the resistance of the test piece was measured in an atmosphere of a temperature of 25° C. and a humidity of 60 cm, and was calculated according to the following formula.

Volume resistivity (Ω・crn) = where, 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. In addition, to measure the shielding effect of electromagnetic waves, a sample box of 1.0 x 10 x 30 crn was made using a sheet with a thickness of 3
H2).

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 made from the sheet, and the ratio of the electric field intensity 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 aluminum flakes, aluminum powder, aluminum fibers, and impact-resistant resin used in Examples and Comparative Examples have the following shapes and physical properties.

[Aluminum flakes]

As the aluminum flakes, square aluminum flakes (hereinafter referred to as "A/flake") having a cross-sectional area of IX1 and a thickness of 0.0311111 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]

As an aluminum fiber, the length is approximately 6101. Diameter is 65
Micron aluminum O fiber (hereinafter referred to as "Al! fiber") was used.

(Manufacture of AC8 (1)) Chlorinated polyethylene of Mooney viscosity cuff 6 [chlorine content 40.6% by weight, hereinafter r
Cl-P E(a)J': 11600g,
Polyvinyl alcohol (saponification degree 95%) 32゜0I
l and 8. O1! water (ion-exchanged water) was added.

The mixture was then vigorously stirred at room temperature (approximately 23°C). Add 456 monomer to this dispersion while stirring at room temperature.
0g of styrene and 1520g of acrylonitrile, 320g of liquid paraffin as a lubricant, 1 as a polymerization initiator
6.0 g of tertiary-natyl peracetate and 16.0.9 g of tertiary-dodecyl mercaptan as chain transfer agent were added. After replacing the upper part of the suspension of this reaction system with nitrogen gas, the temperature was raised to 105°C. After polymerization was conducted at this temperature for 4 hours with stirring, polymerization was further conducted at a temperature of 145° C. for 2 hours. Then, after cooling this reaction system to room temperature, the obtained polymer (grafted product)
was thoroughly washed with water. The obtained graft product was dried at 50° C. under reduced pressure day and night. Polymerization conversion rate (relative to monomer used in polymerization) is 95.4
%, and was in the form of a slightly coarse powder. The content of rubbery material in this grafted product [hereinafter referred to as rAcs(1)J] was 20.3% by weight.

2% by weight of a dibutyltin malate stabilizer (manufactured by Sankyoki Gosei Co., Ltd., trade name: Stann BM) was added to the obtained AC8 (1), and the roll surface was set at 180°C. Kneading was carried out for 10 minutes. The resulting mixture was pressed for 5 minutes under a pressure of 100 kg/cm2 using a press set at 200°C, and then pressed at 100 kf/cm2 using a water-cooled press.
Pressing was carried out for 2 minutes under pressure of . Izot impact strength of the obtained press plate (with knot f) u 8.0 k
g-an/cm, and the tensile strength is 325 kg/cm
It was 2. Moreover, the Vicat softening point was 938°C.

(Manufacture of A CS (2)) C1-PE (a
) usage amount is 6.0 kjL, styrene usage amount is 12
80. ! 9 and the amount of acrylonitrile used is 3209
Polymerization was carried out under exactly the same conditions as in the case of ACS (1), except that ACS (1) was changed. After the polymerization was completed, filtration, washing with water, and drying were performed in the same manner as in the case of AC8(1) to produce a polymer (grafted product). This graft [hereinafter [Ac5(2)]
The polymerization conversion rate was 95.3%, and the material was in the form of a slightly coarse powder. Note that the content of rubbery substances in this ACS (2) was 796%.

[Production of mixture (1)] Instead of the above A CS (1), A CS (2)
and acrylonitrile-styrene copolymer resin (acrylonitrile content: 23% by weight, hereinafter referred to as "As") at a mixing ratio of 1:3 under the same conditions as AC8 (1). The resulting mixture [hereinafter referred to as “
A pressed plate was produced from the mixture (referred to as January) in the same manner as in the case of AC5 (1).The Izot impact strength (notched) of the obtained pressed plate was 7.8 kg-cm/cm, and the tensile strength It weighed 330 kg and weighed 7cm2T.

Moreover, the Vicat softening point was 93.7°C.

[Production of mixture (2)] In producing 100 parts by weight and 400 parts by weight of the above mixture of chlorinated polyethylene having a Mooney viscosity of 75 (chlorine content 362% by weight, non-grade, molecular weight of raw material polyethylene approximately 250,000). A, S and 2 parts by weight of the dibutyltin malate stabilizer used in A.
Melting crosstalk was performed in the same manner as in the case of C8(1). The obtained mixture [hereinafter referred to as "mixture (2)"] was
A press plate was manufactured in the same manner as in case (1). Izo impact strength of the obtained pressed plate (with C notches) #i8.
o Ig -cm 7 cm, and the tensile strength is 340
kg/cm''. Also, the Vicat softening point was 94.
The temperature was 5°C.

Examples 1 to 2, Comparative Examples 1 to 4 ACS (1), ACS (2), mixture (1) and mixture (2), and AI! Flake, AI! The fibers and A/powder were each tri-blended for 5 minutes using a Henschel mixer at the blending ratios shown in Table 1. Each mixture obtained was transferred to a twin screw extruder (diameter: 3
Pellets (composition) were produced by melt-kneading the resin at a resin temperature of 200[deg.] C. using the following method.

Each of the resulting compositions was molded into a 3 m thick test piece using a 6 oz injection molding machine preset at 20°C.

The volume resistivity and transmission attenuation of each test piece thus obtained were measured. The results are shown in Table 2.

From the results of the above Examples and Comparative Examples, the composition obtained by the present invention exhibits an effect on electromagnetic wave transmission attenuation as an electromagnetic wave shielding material by mixing 5 to 50 volumes of aluminum powder, and It is clear that the mechanical properties such as tensile strength, bending strength and impact strength as a conventional molded product are also sufficiently maintained.

Patent applicant: Showa Denko Co., Ltd. Agent: Patent attorney Sei Kikuchi

Claims (1)

[Scope of Claims] (A) (1) chlorinated polyethylene, (2) a graft copolymer obtained by graft copolymerizing chlorinated polyethylene with styrene and at least one other vinyl compound, and (3) An impact-resistant resin containing at least one copolymer of styrene and at least one other vinyl compound (however, chlorinated polyethylene and styrene and at least one other vinyl compound occupying the impact-resistant resin) The total amount of chlorinated polyethylene graft copolymerized is 5 to 40% by weight.
and (B) Aluminum alloy is a composition consisting of powdered, fibrous and/or flaky materials of an alloy containing aluminum as a main component, and the impact-resistant resin in the composition is An impact-resistant resin composition having a blending ratio of 50 to 95 volumes.