JPH0468349B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention relates to a conductive resin composition, particularly a conductive resin composition containing an aluminum alloy filler. [Prior art] Resin materials made by adding conductive fibers to insulating organic polymer materials have come to be widely used in various parts such as resistance heating elements, resistors, antistatic materials, and shielding materials. . To this end, it is required to impart electrical conductivity to the resin without impairing its inherent physical properties, such as moldability. One method for imparting conductivity to a resin is to mix a conductive filler into the resin.
According to this method, a molded body or sheet obtained by molding a resin mixed with a conductive filler can be used as a component as it is, so it is a useful method that can be expected to reduce processing costs. The conductive fillers blended into conventional conductive resins include carbon black, graphite powder,
Carbon-based fillers such as carbon fiber, fine metal powders such as nickel, silver, and copper, metal fibers such as brass, stainless steel, and aluminum, and aluminum-coated glass fibers,
Composite fillers such as nickel-coated mica powder are undesirable because they have the following drawbacks. In the case of carbon-based fillers, their uses are limited because they are not flame retardant like metals, and their hue is also limited, resulting in poor decorative properties. Among fine metal powders, nickel and silver are expensive and impractical, while copper powder requires surface treatment to prevent surface oxidation to ensure stable conductivity. Fibers made of stainless steel, brass, etc. have a high specific gravity and therefore have poor dispersibility, and have the disadvantage that the resulting molded product also has a high specific gravity. With composite fillers, there is a risk that the coating layer will peel off during the molding process, resulting in a decrease in conductivity. In addition to the above-mentioned conductive fillers, aluminum conductive fillers are attracting attention because they have the advantage of being lightweight and inexpensive. It has the disadvantage that sufficient conductivity cannot be obtained because the contact resistance between the materials increases. Therefore, like the other conductive fillers mentioned above, in order to obtain the desired conductivity, it is necessary to increase the amount of filler blended or to form the filler into a shape that is difficult to mold, such as fibers or flake-like coarse particles. Nakatsuta. [Problems to be Solved by the Invention] The present invention solves the drawbacks of the conventional conductive fillers described above, and can impart sufficient conductivity to the resin in an amount within a range that does not impair the physical properties of the resin itself. An object of the present invention is to provide a conductive filler. An object of the present invention is to provide an aluminum-based conductive filler that can impart sufficient conductivity to a resin in a small amount without sacrificing the lightweight and inexpensive advantages of aluminum. [Means for Solving the Problems] The conductive resin composition provided by the present invention is characterized by incorporating an aluminum alloy filler containing 5 to 40% by weight of nickel. The conductive filler blended into the resin composition of the present invention is made of an aluminum-nickel alloy containing 5 to 40% by weight of nickel. In the aluminum-nickel alloy of the present invention, if the nickel content is less than 5% by weight, sufficient conductivity cannot be obtained, while if the nickel content exceeds 40% by weight, the specific gravity of the alloy increases and it is dispersed. This is not preferable because it not only deteriorates performance but also increases cost. The preferred nickel content is 20-30% by weight. Furthermore, the aluminum-nickel alloy of the present invention may contain silicon, iron, copper, magnesium, manganese, cobalt, chromium, molybdenum,
Components such as silver, calcium, indium, bismuth, antimony, zinc, lead, vanadium, titanium, cadmium, tin, gallium, and zirconium can also be added. There is no particular restriction on the amount added, but if the amount added is 10% by weight or less, the above object can be achieved without particularly impairing the desired effects of the present invention. 5 for alloy specific gravity
It is desirable to do the following. The shape of the aluminum alloy filler having the alloy composition described above is not particularly limited, but fillers in the form of granular powder, flake powder, or fibers are used. Generally, resin compositions containing granular powder have good moldability, and highly conductive molded bodies or sheets can be formed from resin compositions containing flaky powder or fibers. There are no particular restrictions on the particle size of the filler, but the smaller the particle size, the more difficult it is to impart sufficient conductivity, and the larger the particle size, the worse the dispersibility and moldability, which may affect the physical properties of the resulting molded product or sheet. The selection is made taking into consideration that it may have an undesirable effect on Typically particle size 50
~1000μm granular powder, particle size 150-3000μm and thickness 1
~100 μm flake powder or fibers with a diameter of 10-150 μm and a length of 500-30000 μm are used. A mixture of these may be used. The resin in which the aluminum alloy filler of the present invention is blended may be any resin that can be blended with conventional conductive fillers, such as AS resin, ABS resin, polyethylene, polypropylene, noryl, polycarbonate, polystyrene, polyamide, polychloride, etc. Vinyl, silicone resin, EVA resin, EEA resin, etc. are used. The content of the aluminum alloy filler is determined depending on the required conductivity, but is preferably 10 to 40% by volume. If the amount is less than 10% by volume, sufficient conductivity cannot be obtained, and if it exceeds 40% by volume, the physical properties of the resin will be impaired, which is not preferable. When the aluminum alloy filler is in the form of flakes or fibers, a smaller amount than the above-mentioned amount (for example, 5 to 30% by volume for flakes and 2 to 20% by volume for fibers) is sufficient. Although it is essential to blend the aluminum alloy filler into the resin composition of the present invention, other optional components such as plasticizers, heat-resistant anti-aging agents, weathering agents, stabilizers, dispersants, mold release agents, and antistatic agents may be added as necessary. Agents, impact modifiers, pigments, coupling agents, antioxidants, and other conductive fillers may also be included. [Examples] The following examples are illustrative for specifically explaining the present invention, and the present invention is not limited to these examples. Example 1 A resin composition was prepared by blending granular aluminum alloy powder (particle size: 149 to 350 μm) and apparent specific gravity of 3.1, containing 80% by weight of Al and 20% by weight of Ni, into ABS resin. The blending ratio was 15% by volume. The resin composition was injection molded according to the elastic method to obtain a plate-shaped molded product with a thickness of 3 mm and a square shape of 10 cm. The volume resistivity of this molded body was measured according to ASTM D257 and was found to be 5×10 ⁰ Ω-cm. Example 2-6 and Comparative Example 1-3 Using aluminum alloy fillers having the alloy compositions shown in Table 1, the volume resistivity of molded bodies obtained in the same manner as in Example 1 was measured. . The results were as shown in Table 1.

[Table] It was confirmed that a molded article obtained from a resin composition containing an aluminum alloy filler containing 5 to 40% by weight of nickel had high electrical conductivity. [Effects of the Invention] When the resin composition containing the aluminum alloy filler of the present invention is used, a molded article or sheet having exceptionally superior conductivity can be formed compared to when a filler consisting of pure aluminum is blended. be able to. This is because the aluminum-nickel alloy filler of the present invention has a conductive film made of aluminum oxide and nickel oxide, rather than the conventional electrically insulating oxide film that is formed on single aluminum. This is thought to be due to the extremely low contact resistance. In the present invention, as described above, since the contact resistance between the fillers is small, the amount of fillers blended can provide at least a sufficiently high conductivity. Therefore, there is no fear that the moldability of the resin will be impaired, which conventionally occurs due to the need to increase the amount of filler blended.
By using the resin composition of the present invention, not only can a compact molded article or sheet be formed, but also the risk of deterioration in physical properties such as strength of the resin itself can be avoided. Furthermore, in the present invention, excellent conductivity can be obtained even when granular powder with high moldability or flake powder with relatively small particle size is used as a filler. It is possible. Therefore, according to the present invention, the filler can be blended into the resin in a uniformly dispersed state, and as a result, a molded article or sheet with uniform conductivity can be molded. In the present invention, as described above, since the amount of filler blended is small, the obtained molded article or sheet has excellent physical properties. In particular, since the aluminum-nickel alloy filler of the present invention has higher strength than the aluminum filler, use of the resin composition of the present invention can provide not only electrical conductivity but also a reinforcing effect. The present invention also maintains the inherent low cost, low specific gravity, and excellent decorative properties of the aluminum filler, so it is possible to form lightweight moldings or sheets with excellent hues at low cost.

Claims (1)

[Claims] 1. Aluminum as the main component, Nickel 5-40
A conductive resin composition containing an aluminum alloy filler containing % by weight. 2. The composition according to claim 1, wherein the aluminum alloy filler has the form of granular powder, flaky powder and/or fiber. 3 Aluminum alloy filler has a particle size of 50 to 1000μm
The composition according to claim 2, which is a granular powder. 4 Aluminum alloy filler has a diameter of 150 to 3000 μm
The composition according to claim 2, which is a flaky powder having a thickness of 1 to 100 μm. 5. The composition according to claim 2, wherein the aluminum alloy filler is a fiber having a diameter of 10 to 500 μm and a length of 500 to 30,000 μm. 6. The composition according to any one of claims 1 to 5, which contains 10 to 40% by volume of an aluminum alloy filler.