JPS6312663A - Colorable electrically conductive resin composition - Google Patents

Abstract

PURPOSE:To obtain the titled composition colorable to desired color, having excellent antistatic effect and suitable for antistatic part such as magazine for IC, etc., by compounding electrically conductive fiber and expanded graphite to a base resin at specific ratios. CONSTITUTION:100pts.(wt.) of a thermoplastic resin (e.g. polyethylene, polypropylene, etc.) is compounded with (A) 1-20pts. of electrically conductive fiber (e.g. metallic fiber, carbon fiber, etc.) having a fiber diameter of 3-20mum and a fiber length of about 1-15mm and (B) 5-30pts. of expanded graphite having a bulk density of <=0.2g/cc, preferably 0.1-0.005g/cc.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a colorable conductive resin composition that can be colored to a desired color tone and has an excellent antistatic effect.

Conventionally, conductive resins with excellent antistatic effects are used for IC and L
It is used in carrier cases to protect SI, etc., and packaging materials for electronic components.

The conductive resin used in this case has a price,
Most resins are blended with carbon black due to issues such as the balance of mechanical properties and moldability.

However, although resin containing carbon black has good electrical conductivity, the resulting molded product has a black tone, making it unsuitable as a conductive material when different colors are required; The current situation is that it cannot be used in areas where it may be exposed.

For this reason, in recent years, attempts have been made to develop electrosensitive resins that can be colored to a desired color tone. By adding the agent, a molded product with the desired color tone can be obtained.

However, when conductive fibers are mixed with resin, the fibers tend to be oriented parallel to the flow direction of the resin, resulting in the formation of a non-conductive resin layer, albeit partially, on the surface of the resulting molded product. However, in order to obtain an excellent antistatic effect throughout the molded product, a large amount of conductive fiber must be blended, and the physical properties of the electrosensitive resin (e.g. impact resistance, moldability, etc.) This is undesirable as it significantly reduces the

In order to solve the above-mentioned drawbacks, the present inventors have made extensive efforts and found that by adding expanded graphite when blending conductive fibers, good antistatic properties can be achieved even when using a small amount of conductive fibers. The present invention was completed based on the finding that a conductive resin composition that is effective and that can be easily colored into a desired color tone by adding a colorant can be obtained.

The expanded graphite used in the present invention is a powder with a bulk density of 0.2
g/cc or less is appropriate, preferably 0.1~
It is 0.005g/cc. The bulk density of the powder is 0.
If it exceeds 2 g/cc, the amount of resin used as a filler must be increased.

Furthermore, if the bulk density is too low, handling becomes difficult and uniform dispersion in the resin becomes difficult.

The expanded graphite may be manufactured by any known method, and the manufacturing method is not particularly limited.

For example, by reacting graphite, which is a hexagonal crystal of carbon in which six-membered ring polymer layers are layered, with sulfuric acid, an alkali metal, a halogen compound, etc. A graphite intercalation compound bonded with halogen etc. is formed, and this is heated to 100°C or higher, preferably 5°C
By heat-treating at a temperature of 00° C. or higher, expanded graphite whose outer diameter has expanded by about 10 to 300 times in the C-axis direction can be obtained.

Examples of the conductive fibers include metal fibers, carbon fibers, metal-coated glass fibers, and the like. As the metal fibers, metals or alloys such as steel, stainless steel, brass, copper, aluminum, etc. may be made into fibers by known methods such as melt spinning, stretching, extrusion, crack vibration machinability, etc. .

Further, as the carbon fiber, polyacrylonitrile carbon fiber is preferable.

These conductive fibers preferably have a fiber diameter of about 3 to 20 μm and a weave length of about 1 to 15 strands.

The resin used in the present invention includes thermoplastic resins such as polyethylene, polypropylene, polystyrene, AS resin, ABS resin, polyacetal, polycarbonate, polyamide, polyester, and polyvinyl chloride.

The blending amounts are 1 to 20 parts by weight of the conductive fiber and 5 to 30 parts by weight of the expanded graphite to 100 parts by weight of the resin. When this condition is satisfied, a conductive resin composition with excellent antistatic effect (surface resistance value of 10 3 to 10 8 Ω) can be obtained.

If the amount of expanded graphite used is less than 5 parts by weight, a sufficient antistatic effect cannot be obtained, which is not preferable.

Moreover, if the amount exceeds 30 parts by weight, the antistatic effect will not be further improved, so there is no need to add more than 30 parts by weight.

If the amount of conductive fiber used is less than 1 part by weight, the electromagnetic wave shielding effect and antistatic effect will be significantly reduced, which is undesirable. If it is more than 20 parts by weight, the impact resistance of the resulting conductive resin composition will be reduced. Physical properties such as hardness, tensile strength, and moldability deteriorate, which is undesirable.

The composition of the present invention exhibits a stable surface resistance value in the range of 10'' to 1O@Ω, and is light in color, so it can be colored into a desired color by adding any coloring agent. Colorful plastic molded products can be produced.Moreover, the surface resistance of the resulting molded products is almost the same as that without the addition of a colorant.

Therefore, the conductive resin composition with excellent antistatic effect according to the present invention can be used for antistatic parts such as TC magazines, IC trays, semiconductor-related packaging and storage containers, automobile interior parts, etc.
Alternatively, it can be used for parts that require dustproofing.

In addition, the dyes and pigments used when coloring the composition of the present invention are:
Any of those conventionally used for coloring resins may be used, and fatty acids, fatty acid metal salts, low molecular weight polymers, fatty acid waxes, etc. may be added for the purpose of easily dispersing dyes and pigments.

Examples and comparative examples will be described below.

Example I Expanded graphite'(
(manufactured by Nippon Graphite Co., Ltd.) 13 parts by weight and polyacrylonitrile carbon fiber (product name: Torayca T-008, manufactured by Toshisha Co., Ltd.)
13 parts by weight of the conductive resin composition of the present invention (surface resistance value 1.2
, measured according to ASTM D-257).

To 125 parts by weight of these pellets, 6 parts by weight of titanium oxide, 0.6 parts by weight of copper phthalocyanine blue, and 0.6 parts by weight of metal soap.
Mixing a coloring agent (dry color) consisting of 6 parts by weight,
When a test piece measuring 80 x 160 x 3 m was molded using an injection molding machine, the color tone was pale blue.

The test pieces were measured for (a) surface resistance, (I+) volume resistivity, and (viii) formability, and the results are shown in Table 1.

The measurement method is as follows.

(a) Surface resistance value Measured according to ASTM D-257.

(0) Volume resistivity value Measured according to Japan Rubber Boundary Standard, 5RIS-2301.

(c) Half-life time Measured according to JIS-L-1094.

(=)Moldability Comprehensively evaluates the stability of injection molding, the appearance and dimensional accuracy of the molded product.

◎...Very good, ○...Good×...
...Bad Example 2 100 parts by weight of ABS resin (product name: GR-1000, manufactured by Denki Kagaku Kogyo Co., Ltd.), 13 parts by weight of expanded graphite (manufactured by Nippon Graphite Co., Ltd.) with a bulk density of 9.020 g/cc, and polyester were added. The present invention is prepared by blending 13 parts of acrylonitrile carbon fiber (trade name: Torayca T-008, manufactured by Toshisha Co., Ltd.) and kneading it into pellets using a 40-fin single-screw extruder (Full Flight, L/D-28). conductive resin composition (surface resistance value 1.8 x 10
To 125 parts by weight of this pellet, 1 part of titanium oxide 5-fold!, quinacridone red (trade name: RT-7) is obtained.
90D.

When a coloring agent (dry color) consisting of 0.6 parts by weight (manufactured by DuPont) and 0.6 parts by weight of metal soap was mixed and an 80 x 160 x 3 dragon test piece was molded using an injection molding machine, the color tone was pale red. .

Thereafter, tests similar to those in Example 1 were conducted and the results are shown in Table 1.

Example 3 The polypropylene resin used in Example 1 had an ME value of 6.5,
All formulations were the same as in Example 1 except for changing to bulk density polyethylene with a density of 0.95.

The surface resistance value of the conductive resin composition of the present invention is 1.5.
X 10”Ω.

Thereafter, tests similar to those in Example 1 were conducted and the results are shown in Table 1.

Example 4 Nylon resin (product name: Ube Nylon 66B2020,
100 parts by weight of carbon fiber (product name: Pyrofil X 7006KA Mitsubishi Rayon product)
1i 1 part, expanded graphite with a bulk density of 0.018 g/cc (manufactured by Nippon Graphite Co., Ltd.) 10 parts by weight, copper phthalocyanine blue 1fE
and 1 part by weight of calcium stearate,
Pellets were obtained using a 40fi screw vent extruder. After drying the pellets at 80°C for 5 hours, test pieces of 80 x 160 x 3 mm were molded using an injection molding machine, and the color tone was blue.

Thereafter, tests similar to those in Example 1 were conducted and the results are shown in Table 1.

Comparative Example 1 The other formulations were the same as in Example 1 except that the amount of expanded graphite used in Example 1 was 2 parts.

The surface resistance value of the composition before adding the colorant is 1.2.
X 10'Ω. Thereafter, tests similar to those in Example 1 were conducted and the results are shown in Table 1.

Comparative Example 2 The formulation was the same as in Example 1 except that the amount of polyacrylonitrile carbon fiber used in Example 1 was changed to 0.5 parts by weight.

The surface resistance value of the composition before adding the colorant is > 1
It is 0'Ω. Thereafter, tests similar to those in Example 1 were conducted and the results are shown in Table 1.

Comparative Example 3 The formulation was the same as in Example 1 except that the amount of polyacrylonitrile carbon fiber used in Example 1 was changed to 25 parts by weight.

The surface resistance value of the composition before adding the colorant was 9.6.
X10-''Ω. Thereafter, tests similar to those in Example 1 were conducted and the results are shown in Table 1.

As can be understood from Table 1 and above, the colorable conductive resin composition of the present invention can be used with various colorants (dry color,
A desired color tone can be obtained by adding a masterbatch, etc.), and even after toning, the half-life time is 2 to 3 seconds, and the antistatic effect is excellent.

Claims (1)

[Scope of Claims] A colorable conductive resin composition, characterized in that 1 to 20 parts by weight of conductive fibers and 5 to 30 parts by weight of expanded graphite are blended with 100 parts by weight of a thermoplastic resin.