JPH06215618A - Manufacture of conductive resin composition containing tic whiskers - Google Patents

Abstract

PURPOSE:To provide a manufacturing method for a conductive resin composition containing such Ti whiskers of suitable conductivity and excellent material strength that the volume TiC whisker content of the composition may be finely adjusted within a constant range. CONSTITUTION:TiC whiskers 0.3 to 2.0mum across and 5 to 50mum long of mutually different aspect properties are combined with one another to be used in the process of compounding the TiC whiskers with matrix resin, and the volume TiC whisker content (Vf) of a conductive resinous composition is finely adjusted within a range of 5 to 35%.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a conductive resin composition containing TiC whiskers, which has excellent conductivity and material strength, and whose volume resistivity can be finely adjusted within a certain range. .

[0002]

2. Description of the Related Art A plastic material having conductivity is widely used as a member for preventing static electricity of electronic devices and parts thereof, electromagnetic wave absorption, electromagnetic wave shielding and the like. Conventionally, as a means of imparting conductivity to a plastic material, a method of dispersing and compounding a conductive substance in a matrix resin component to fill composite molding has been regarded as a main technique, and copper, iron as a conductive substance, iron,
Powders such as nickel, metal-based fillers such as fibers or foil pieces, carbon black, graphite powder or carbon-based fillers such as carbon fibers are used alone or in combination (for example, JP-A-55-160881). Gazette, ibid. 57
-123858, 58-73198, 63-301596, etc.).

Although the above-mentioned conductive plastic material exhibits excellent conductive performance, it has a drawback that a high-strength structure cannot be obtained because the material strength largely depends on the matrix resin. Therefore, there is a problem that the application is limited to the application exposed to severe conditions. The present inventor has developed a conductive plastic material having a composition in which TiC whiskers are homogeneously dispersed in a matrix resin as a composite conductive material having suitable conductive performance and excellent material strength in order to solve such drawbacks. However, it has already been proposed as Japanese Patent Application No. 3-283899.

[0004]

According to the TiC whisker reinforced conductive plastic material according to the above-mentioned prior art, the matrix resin is mediated by a unique conductive mechanism based on the bond structure between Ti-C or Ti-Ti. Suitable conductivity performance can be imparted to the composite, and at this time, the volume content (Vf) of the TiC whiskers to be composited can be varied to adjust the degree of conductivity. However, there is a limit to the control of conductivity by changing the volume content (Vf) of TiC whiskers, and there is a drawback that the conductivity characteristics cannot be adjusted in a delicate range.

An object of the present invention is to provide a method for producing a conductive resin composition containing TiC whiskers, which has suitable conductive properties and excellent material strength and is capable of finely adjusting the volume resistivity within a certain range. To do.

[0006]

In order to achieve the above object, a method for producing a conductive resin composition containing TiC whiskers according to the present invention has a diameter of 0.3 in a step of compounding TiC whiskers with a matrix resin. ~ 2.0μ
m and a length of 5 to 50 μm, TiC whiskers having different aspect properties are mixed and used, and the volume content (Vf) of the TiC whiskers is adjusted within the range of 5 to 35%. To do.

The production history of the TiC whiskers used as the conductive filler of the present invention is not particularly limited. Therefore, for example, a known method of reacting titanium halide with carbon monoxide or carbon tetrachloride, or a specific amount of carbon for a titanium source raw material composed of titanium dioxide or / and an alkali metal titanate developed by the present applicant. A TiC whisker produced by a method of mixing a raw material and a transition metal chloride and reacting by heating (Japanese Patent Laid-Open No. 4-193800) can be used. However, the shape of the TiC whiskers is 0.3 to 2.0 μm in diameter and 5 to 5 in length.
Aspect characteristics in the range of 0 μm are selected and used.

Examples of the matrix resin include phenol type, epoxy type, unsaturated polyester type, diallyl phthalate type, polyethylene, polyvinyl chloride, polyvinyl alcohol, polyamide, polyimide, polyurethane, polystyrene, polyvinyl acetate, and tetrafluoroethylene. Although various thermosetting or thermoplastic resins can be mentioned, an epoxy resin is preferably used for the purpose of the present invention.

The composite ratio of TiC whiskers to the matrix resin is set in the range of 5 to 35% as the volume content (Vf) of TiC whiskers. This volume content is 5
When it is less than%, it becomes difficult to impart suitable conductivity and material strength, and when it exceeds 35%, voids are formed between the TiC whiskers and the matrix resin in the compounding step, and the compounding characteristics are deteriorated.

The conductive resin composition containing the TiC whiskers of the present invention can be manufactured as follows. T
When targeting a resin composition having a volume content (Vf) of iC whiskers of 5 to 10%, TiC whiskers are added little by little while stirring a matrix resin solution in which a curing agent, a curing accelerator, etc. are mixed in advance. And mix. Then, the mixture is sufficiently kneaded by a roll kneading device or the like to be uniformly dispersed,
Degas under vacuum and place in the mold. Vacuum degassing is performed again in the mold, press molding is performed, and then the resin component is cured at a predetermined temperature to form a composite composition.

The volume content (Vf) of TiC whiskers
When a resin composition of 10% to 35% is targeted, TiC whiskers are dispersed in water in which a binder component such as polyvinyl alcohol is dissolved, followed by pressure filtration and drying of the filter cake. Process into a predetermined shape. The surface of the obtained TiC whisker preform is smoothed, if necessary, sprayed with a binder solution and dried, then immersed in a matrix resin solution for vacuum deaeration, and subsequently pressurized to the inside of the structure of the TiC whisker preform. Is forcibly impregnated with the matrix resin liquid. The composite molded body after the impregnation treatment is put into a mold and cured by heating.

In the above compounding step, the diameter of the TiC whiskers used as the conductive filler is 0.3 to 2.0 μm.
The main requirement of the present invention is to use a plurality of types having different aspect characteristics within a range of m and a length of 5 to 50 μm, and to appropriately mix and use them. As an embodiment, for example, a diameter of 0.
3 to 0.5 μm, length 5 to 10 μm, diameter 0.5 to 1.
5 μm, length 10-30 μm, and diameter 1.0-2.
Three types of TiC whiskers having different aspect properties, such as 0 μm and a length of 25 to 50 μm, are separately selected and adjusted and compounded according to the volume resistivity of the target conductive resin composition. Therefore, T having an aspect property in the above range
When one type of iC whisker is used, it is not possible to finely adjust the conductive performance. The reason why the aspect property is within the range of 0.3 to 2.0 μm in diameter and 5 to 50 μm in length is that the aspect property in this range is particularly effective for fine adjustment of conductive performance, and This is because it is difficult to manufacture a TiC whisker having a diameter and a length that exceed it.

[0013]

[Function] TiC whiskers are fine fibrous substances composed of cubic needle-like single crystals, are ultra-hard substances with extremely high hardness, and compositionally form a Ti-C or Ti-Ti bond structure. Shows a unique conductive mechanism based on. Therefore, this super-hard fiber morphology gives a high degree of material strength by the composite reinforcement of the matrix resin, and at the same time, excellent conductive performance is imparted by being homogeneously dispersed in the state where numerous contact points are present. According to the method, TiC whiskers having different aspect properties within a specific range are mixed and used in the compounding step with the matrix resin, and the volume content (V
By adjusting f) to 5 to 35%, the degree of mutual contact of TiC whiskers inside the tissue can be slightly changed.

The volume resistivity of the obtained conductive resin composition is adjusted to a desired value within the range of 1 × 10 ^-2 to 10 ^-3 through the action of adjusting the content of TiC whiskers and controlling the content thereof. It becomes possible to adjust.

[0015]

EXAMPLES Hereinafter, examples of the present invention will be described in comparison with comparative examples. The aspect characteristics of the TiC whiskers used in each example are as follows. A property: diameter 0.3 to 0.5 μm, length 5 to 15 μm B property: diameter 0.5 to 1.5 μm, length 10 to 30 μm
m C property: diameter 1.0 to 2.0 μm, length 25 to 50 μm
m D property: diameter 0.3 to 2.0 μm, length 5 to 50 μm

Examples 1 to 3 While mixing a matrix resin solution in which 16.7 g of a curing agent was previously mixed with 83.3 g of an epoxy resin solution, the mixing ratio of TiC whiskers of A property, B property and C property was changed. And added little by little, and stirring was continued to mix well. Then, the mixture is mixed with three rolls (roll spacing
(0.2 mm) and kneaded for 10 minutes, degassed in vacuum, and filled in a mold whose surface is coated with a release agent. After vacuum defoaming the filling in the mold again, pressurization is applied by applying a pressure of 100 kg / cm ² , and then the resin component is cured under heating conditions of 80 ° C. for 2 hours and 150 ° C. for 2 hours. Volume content (Vf) 10
% Conductive resin composition was produced. The volume resistivity of each conductive resin composition produced was measured, and the results are shown in Table 1 in comparison with the compounding ratio and volume content of TiC whiskers. The volume resistivity was measured according to ASTM D257.

Comparative Examples 1 to 2 As the TiC whiskers, one having properties A and one having properties D were used alone, and the other conditions were the same as in Example 1 except that the conductive resin composition had a volume content (Vf) of 10%. Manufactured.
The volume content of each conductive resin composition obtained was measured, and the results are also shown in Table 1.

Examples 4 to 9 To 1.5 liters of water in which 1% by weight of polyvinyl alcohol was dissolved, 100 g of TiC whiskers of A property, B property and C property were added at different mixing ratios, and the mixture was placed in a juicer mixer for 3 minutes. It was dispersed by stirring. The dispersion was pressure filtered with a pressure filtration device under a pressure of 3 kg / cm ² , and the obtained wet cake was dried at a temperature of 80 ° C. Then, it was cut into a plate shape with a band saw, and the surface was finished to be a smooth surface with a sandper to form a TiC whisker preform.
A polyvinyl alcohol aqueous solution having a concentration of 1% by weight was sprayed onto this preform, dried at a temperature of 110 ° C., and then set in an impregnation container. An epoxy resin [Epicoat 828] manufactured by Yuka Shell Epoxy Co., Ltd. 20 parts by weight of a curing agent [“Epicure Z” manufactured by Yuka Shell Epoxy Co., Ltd.) was mixed and vacuum-deaerated matrix resin solution was injected, and the mixture was sufficiently deaerated under reduced pressure of 10 mmHg and further autoclaved. It was transferred and pressure-impregnated for 1 hour while applying a pressure of 5 kg / cm ² . The impregnated composite molded article was placed in a mold, pressurized with a gauge pressure of 5 kg / cm ² , and heat-treated at 80 ° C. for 2 hours and 150 ° C. for 2 hours to cure the resin component. In this way, the volume content is about 20.
% And about 30% conductive resin composition was produced. The volume resistivity of each conductive resin composition obtained was measured, and the results are shown in Table 1 in comparison with the compounding ratio and volume content of TiC whiskers.

Comparative Examples 3 to 6 As TiC whiskers, B property, C property, and D property were used individually, and other conditions were the same as in Example 4, and the volume content (Vf) was about 20%. And about 30% of a conductive resin composition was produced. The volume resistivity of each obtained conductive resin composition was measured, and the results are also shown in Table 1.

[0020]

[Table 1]

From the results shown in Table 1, it was confirmed that the conductive resin compositions according to the examples manufactured according to the present invention had a smaller variation in volume resistivity than the comparative examples, and the conductive performance was finely adjusted. To be

[0022]

As described above, according to the present invention, TiC whiskers having different aspect properties are mixed and used as the conductive filler, and the volume content (Vf) of the TiC whiskers is adjusted so that the volume resistance value falls within a certain range. It is possible to produce a conductive resin composition finely adjusted to a desired value. In addition, since the material as a whole has a high level of electrical conductivity and material strength, it is expected to be useful as a member such as an antistatic material, an electromagnetic wave absorbing material, an electromagnetic wave shielding material used under particularly severe conditions. It

Claims (1)

[Claims] 1. In the step of compounding TiC whiskers with a matrix resin, Ti having different aspect properties within a diameter range of 0.3 to 2.0 μm and a length range of 5 to 50 μm.
A method for producing a conductive resin composition containing TiC whiskers, which comprises blending and using C whiskers and adjusting the volume content (Vf) of TiC whiskers within a range of 5 to 35%.