JPS58136644A - Vinyl chloride resin composition - Google Patents

Abstract

PURPOSE:To provide a vinyl chloride resin compsn. which is lightweight, can be easily molded and has high shieldability against electromagnetic wave, by blending aluminum (alloy) powder, etc. CONSTITUTION:90-50vol% vinyl chloride resin having a polymn. degree of 400-4,500 and 10-50vol% at least one member selected from aluminum (alloy) powder having an average particle size of pref. 250-20 mesh, aluminum (alloy) fibrous material having a diameter of pref. 0.002-0.2mm. and aluminum (alloy) flake having a cross-sectional area of pref. 0.1X0.1-5X5mm., are blended together.

Description

DETAILED DESCRIPTION OF THE INVENTION q] Object of the Invention The present invention relates to a vinyl chloride resin composition. More specifically, (A) vinyl chloride resin and (B) aluminum deaf or aluminum alloy powder not only have a high electromagnetic wave shielding property, but also have a higher shielding ability than gold IA''lB.
The object of the present invention is to provide a vinyl chloride resin composition that is lightweight and easy 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.

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 have searched various ways to obtain a synthetic resin composition that has these drawbacks and has excellent electromagnetic wave shielding performance, and as a result, (A) Vinyl chloride. It is a composition consisting of "powder-like material, mechanical fiber-like material and/or flake-like material" (hereinafter referred to as "aluminum-deprived powder material, etc.") of a resin and an alloy as a main component. A vinyl chloride resin composition in which the composition ratio of vinyl chloride resin is 50 to 90% by volume is a resin composition that not only has good electromagnetic wave shielding performance but also has various characteristics (effects). We discovered something and arrived at the present invention.

□ Effects of the invention In other words, the vinyl chloride resin composition obtained by the present invention not only has extremely excellent electromagnetic wave shielding performance, but also has the following effective characteristics.

(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) 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.

The electromagnetic wave shielding material obtained by the present invention not only has extremely good electromagnetic wave absorption 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) Helding material for office equipment such as fax machines, printers, word processors, etc. (2) Consumer home appliances and electronic equipment such as televisions and videos,
Internal parts of housings for electrical and electronic equipment such as computers and communication equipment, ■ Detailed Description of the Invention (A) Vinyl chloride resin The vinyl chloride resin used in the present invention is a vinyl chloride homopolymer and vinyl chloride. The degree of polymerization of this vinyl chloride resin, which is a copolymer of at most 50% by weight (preferably 45% by weight or less) of a compound having at least one double bond that can be copolymerized with vinyl chloride, is usually 40% by weight.
0 to 4500, particularly preferably 400 to 1500. Representative examples of compounds having at least one double bond include vinylidene chloride, ethylene, propylene,
Mention may be made of vinyl acetate, acrylic acid and methacrylic acid and their esters, maleic acid and their esters and acrylonitrile. These vinyl chloride polymers are obtained by homopolymerizing or copolymerizing vinyl chloride alone or vinyl chloride and the vinyl compound in the presence of a free radical catalyst,
The manufacturing method is widely used and used in many fields.

In producing the composition of the present invention, only vinyl chloride resin may be used as the polymer material, but other types of polymer materials that are miscible with vinyl chloride resin may also be blended. Examples of the polymeric substances include ethylene-propylene-diene ternary copolymerized rubber (EPDM), natural rubber, chloroprene rubber, chlorosulfonated polyethylene comb, and styrene-butadiene-butadiene copolymer rubber ( SBR), acrylonitrile-butadiene copolymer rubbers (NBR), and butadiene homopolymer rubbers [generally Mooney viscosity (, MLL, 4
) is 10 to 150]. These rubber-like materials are well-known from books such as ``11 Synthetic Rubber Handbook'' edited by Kambara et al. (Asakura Shoten, published in 1962) and 11 Plastic Handbook edited by Murahashi et al. (Asakura Shoten, published in 1968). It is.

When these other types of rubbery substances are blended, their blending ratio is at most 50 parts by weight based on the vinyl chloride resin.

(B) Aluminum Powder Among the aluminum powder used in the present invention, the average size of the powder is generally 250 meshes to 20 meshes. Further, the diameter of the fibrous material is generally 0.0020 to 0.20 mg, and a length of 10 W or less is preferable because it is easy to process. Furthermore, as a flake-like material, the cross-sectional area is 0. lX0
Any shape such as circular, square, rectangular, quadrilateral, etc. having 5 x 5 fins from 11 fins can be used;
In particular, it is desirable that the thickness be 0.1 ff111 or less. Among them, one having a rectangular shape with a cross-sectional area of about 1×1ffi and a thickness of about Q, 93 mm has good dispersibility. These powdery, fibrous, or flaky materials may be used alone, but by using two or more of them together, it is possible to achieve the effect with a small mixing ratio in order to achieve the purpose of the present invention. This is suitable because it can be done. Also, the aluminum content in aluminum alloy is usually 80w x
96 or higher.

(C) Compounding ratio The blending ratio of the vinyl chloride resin in the composition of the present invention is 90 to 50% by volume, preferably 90 to 55% by volume, and particularly preferably 90 to 60% by volume. (In other words, the blending ratio of aluminum powder, etc. is 10 to 5
0 capacity, preferably 10 to 45 capacity, especially 1
0 to 40 capacity is suitable). If the proportion of aluminum powder etc. 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 more than 50%, it is extremely difficult to mix it homogeneously with the vinyl chloride resin, and even if a homogeneous composition is made, it does not have enough strength for practical use. It is practically impossible.

(D) Production of composition, production of molded product To produce the composition of the present invention, triblending may be performed using a mixer such as a Henschel mixer commonly used in the vinyl chloride resin industry. , Banbury mixer,
It can be obtained by melt-kneading using a mixer such as a kneader, roll mill, or screw extruder. At this time, a homogeneous composition can be obtained by triblending in advance and melt-kneading the resulting composition (mixture).

Particularly, 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, then molded into pellets, and subjected to the molding described later.

In producing the composition of the present invention, oxygen and heat stabilizers, metal deterioration inhibitors, plasticizers, fillers, lubricants and flame retardants commonly used in the field of cyclized vinyl resins are further added. May be added.

Both the above-mentioned melt mixing and molding must be carried out at a temperature higher than the softening point of the vinyl chloride resin used. parts may suffer 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. In addition, 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 many ways.

Examples and Comparative Examples The present invention will be explained in more detail with reference to Examples below.

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

In addition, the bending strength and bending modulus are ASTM D-7.
90. Additionally, Izot impact strength was measured with a notch according to ASTM D-256. In addition, the volume resistivity test was performed using a resistance meter (manufactured by Takeda Riken Co., Ltd., product name: Digital Multimeter TR-68).
56), using a specimen with a thickness of 21 El, and at a temperature of 2
The resistance of the specimen was measured in an atmosphere of 5°C, humidity, and 60°C, 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. In addition, to measure the electromagnetic wave shielding effect, a sample box of 10 x 10 x 30 Crn was made using sheets with three thicknesses, and a vertical oscillator was placed inside the box at a predetermined frequency (200 MHz).
).

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 via a detector. Radio waves from the transmitter were measured in the same manner with the box manufactured from the sheet removed, and the ratio of power depending on the presence or absence of the sample box was expressed in decibels (dB) and was taken as the amount of electromagnetic wave attenuation of the sample sheet.

The vinyl chloride resin, aluminum flakes, aluminum fibers, and aluminum powder used in the Examples and Comparative Examples have the following shapes and physical properties.

[Vinyl chloride resin (homopolymer)]

Examples of vinyl chloride homopolymers include a homopolymer with a degree of polymerization of about 820 [hereinafter referred to as rpvcc1)J] and a homopolymer with a degree of polymerization of about 1,100 [hereinafter referred to as "pVC(2)J"].
] was used.

[Vinyl chloride resin (copolymer)]

Vinyl chloride-vinyl acetate copolymer containing 15% by weight of vinyl acetate as a vinyl chloride copolymer [degree of polymerization: about 81
0, hereinafter referred to as rpvc(a)j] was used.

[Mixture (1)] As a mixture of vinyl chloride resin, acrylonitrile e-butadiene-styrene terpolymer (acrylonitrile content: about 20% by weight, butadiene content: about 25% by weight)
, styrene content approximately 55% by weight) 20 parts by weight and 100 parts by weight
A mixture (hereinafter referred to as "mixture (1)") consisting of parts by weight of the above-mentioned PVC (1) was used.

[Mixture (2)] Mooney viscosity (M
Acrylonitrile whose L1+, 100°C) is 64
Butadiene copolymer rubber (acrylonitrile content approx. 2
7% by weight) 20 parts by weight and 100 parts by weight of the P V C
(1) [hereinafter referred to as "mixture (2)"] was used.

[Aluminum flakes]

As an aluminum flake, the cross-sectional area is 1 x 1110
111 Square flake-shaped aluminum (hereinafter referred to as "I flake") with a thickness of Q and Q3m was 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 the aluminum fiber, an aluminum fiber (hereinafter referred to as "AI
! fibers) were used.

Example 1. ~12, Comparative Examples 1 to 5 Vinyl chloride resin (30 parts by weight of dioctyl phthalate and 2
5 parts by weight of dibenzyl phthalate and 3 parts by weight of tribasic lead sulfate and 1 part by weight of dibasic lead stearate as stabilizers) and AI! Flake, A/Fiber and AI! Each of the powders was tri-blended for 5 minutes using a Henschel mixer at the mixing ratio shown in Table 1. Each of the obtained mixtures was passed through an extruder (diameter 65
Wr! A composition was produced by melting and kneading the mixture into pellets at a resin temperature of 190° C. using the following method.

A test piece having a thickness of 3 Wm was prepared from each of the obtained compositions using a sheet molding machine preset at 200°C.

The Izot impact strength (measured according to As'rM 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 Ha 30 kp / crn2, and the elongation rate (measured according to JIS K-6723) is 1
It was 5chi.

Note that in Comparative Examples 1.4 and 5, it was difficult to form sheets.

Table 1 (Continued) Part 2
Table 2 Table (Continued) 1) Patented rice cakes that cannot be measured because the sheet cannot be formed Sei Kikuchi, patent attorney and agent for Showa Denko K.K.

Claims (1)

[Scope of Claims] A composition comprising (A) a vinyl chloride resin and (B) a powder, fiber, and/or flake of aluminum or an alloy containing aluminum as a main component; A vinyl chloride resin composition in which the composition ratio of vinyl chloride resin is 50 to 90% by volume.