JPH0718152A - Electrostatic charge-substaining composite material - Google Patents

Abstract

PURPOSE:To obtain the subject material having characteristics comprising instantaneously lowering the potential of electrostatic charge to a constant potential and subsequently sustaining or gradually lowering the potential, excellent in moldability and second processability, and suitably used for the members of IC-using mechanisms, electrostatic members, etc. CONSTITUTION:This composite material comprises (A) 55-92wt.% of an ABS resin and/or a polycarbonate resin, (B) 5-30wt.% of zinc oxide powder having an average particle diameter of 0.1-10mum, and (C) 3-15wt.% of carbon fibers having a fiber length of 2-8mm, and sustains a constant potential, after the electrostatic charge is lowered.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel composite material, more specifically, the charging potential is instantaneously lowered to a certain constant potential,
After that, the present invention relates to a composite material that has characteristics that its potential is maintained or gradually decreases, and that is excellent in moldability and secondary workability, and that is suitable for use as a member of an IC using mechanism or an antistatic member. It is a thing.

[0002]

2. Description of the Related Art Conventionally, as a method of imparting antistatic properties to plastics, for example, as an antistatic material, an electroconductive filler such as a metal-based conductive material or carbon black, or an ion such as a surfactant is used. A method of blending a conductive filler, a method of making the resin itself conductive (using a conductive polymer), and the like are known. When any of these methods receives an electrical stimulus from outside (for example, static electricity due to friction), the resistance value is instantaneously reduced (charge elimination), and the charge potential is made to approach zero. is there.

However, even if the plastic to which the antistatic property is imparted by such a conventional method has a reduced electric resistance, that is, an antistatic effect, when it is used for an IC housing or an IC substrate, for example, this IC Problems such as electrical breakdown and malfunction may occur, and solving such problems is a major issue.

[0004]

Under the circumstances, the present invention provides a composite material with controlled charging performance which can prevent electrical breakdown or malfunction of an IC mechanism due to generation of static electricity. It was made for the purpose of doing.

[0005]

DISCLOSURE OF THE INVENTION As a result of intensive studies to develop a composite material having a controlled charging property, the present inventors have found that a specific thermoplastic resin can contain zinc oxide powder of a specific particle size and A resin composition in which carbon fibers each having a specific fiber length are mixed at a predetermined ratio, the charging potential is instantly reduced to a certain constant potential, and thereafter the potential is maintained or gradually lowered. In addition, it was found that the moldability and the secondary workability are good, and the present invention has been completed based on this finding.

That is, the present invention is at least (A)
ABS resin or polycarbonate resin or a mixture thereof 55 to 92% by weight, (B) average particle size 0.1 to 10
5-30% by weight of zinc oxide powder of μm and (C) fiber length 2
The present invention provides a charge-sustaining composite material comprising 3 to 15% by weight of carbon fiber having a diameter of 8 mm.

In the composition of the present invention, an ABS resin or a polycarbonate resin is used as the matrix resin of the component (A). As the ABS resin (acrylonitrile-butadiene-styrene copolymer), there are resins obtained by various production methods, but any of them can be used.

Further, as the polycarbonate resin,
Bisphenol A-based polycarbonate obtained by a phosgene method in which 2,2-bis (4-hydroxyphenyl) propane (bisphenol A) is reacted with phosgene, or a transesterification method in which bisphenol A is reacted with a carbonic acid diester such as diphenyl carbonate Resin is preferably used. Moreover, a part of bisphenol A is 2,2-bis (4-hydroxy-3,5-dimethylphenyl) propane or 2,2-bis (4-hydroxy-3,3).
A modified bisphenol A-based polycarbonate resin substituted with 5-dibromophenyl) propane or a flame-retardant bisphenol A-based polycarbonate resin can also be used.

In the material of the present invention, as the component (A), an ABS resin or a polycarbonate resin may be used alone, or the ABS resin and the polycarbonate resin may be mixed and used. The content of the component (A) in the material of the present invention needs to be in the range of 55 to 92% by weight. If this content is less than 55% by weight, the charging potential will be excessively lowered, and the appearance, paintability and moldability will be poor, and if it exceeds 92% by weight, the initial reduction of the charging potential will be less likely to occur. .

In the material of the present invention, zinc oxide powder having an average particle size of 0.1 to 10 μm is used as the component (B). When the average particle size of the zinc oxide powder is less than 0.1 μm, the initial charging potential is unlikely to be lowered, and the particles are apt to aggregate, and the appearance is also deteriorated. On the other hand, the average particle size is 10
If it exceeds μm, the charging potential is excessively lowered.

The content of the component (B) in the material of the present invention needs to be in the range of 5 to 30% by weight. If this content is less than 5% by weight, the initial charging potential is unlikely to decrease, and if it exceeds 30% by weight, the appearance, paintability and moldability deteriorate.

In the material of the present invention, carbon fiber having a fiber length of 2 to 8 mm is used as the component (C). The type of carbon fiber is not particularly limited, and either polyacrylonitrile-based or pitch-based can be used. If the fiber length of this carbon fiber is less than 2 mm, the initial decrease in the charging potential is unlikely to occur, and if it exceeds 5 mm, the decrease in the charging potential becomes excessive and the appearance, paintability and moldability deteriorate.

The content of the component (C) in the material of the present invention must be in the range of 3 to 15% by weight. If the content is less than 3% by weight, the initial decrease in the charging potential is unlikely to occur, and if it exceeds 15% by weight, the decrease in the charging potential becomes excessive, and the appearance, paintability and composition are deteriorated.

In the material of the present invention, the zinc oxide powder as the component (B) and the carbon fiber as the component (C) may be, if desired,
You may use, after surface-treating with a suitable surface treating agent. Examples of the surface treatment agent include silane coupling agents, titanate coupling agents, silica powder, silicone oil, higher fatty acids, higher alcohols and waxes.

Further, in the material of the present invention, if desired, other thermoplastic resins, other metal fillers, barium sulfate, calcium carbonate, clay, talc, mica, etc. may be used as long as the object of the present invention is not impaired. Inorganic fillers and organic fillers, as well as various additives commonly used in resin compositions, such as lubricants, colorants, stabilizers, antioxidants, ultraviolet absorbers, flame retardants, plasticizers and the like can be blended. .

The composite material of the present invention can be prepared by a conventional method. For example, the above-mentioned component (A),
It can be prepared by melt-kneading the component (B), the component (C), and various additives used as necessary according to a conventional method to form a composite. Melt kneading can be performed by, for example, a method using a Henschel mixer, a single-screw or twin-screw extruder, a Banbury mixer, a roll or the like, and other conventional methods, but particularly, using a Henschel mixer, an extruder, a Banbury mixer. Is preferred.

[0017]

INDUSTRIAL APPLICABILITY The composite material of the present invention has the characteristic that the charging potential is instantly lowered to a certain constant potential, and thereafter the potential is maintained or gradually lowered.
It is preferably used as a member of an IC using mechanism (for example, a housing, a substrate, etc.), a static electricity generation preventing member (for example, a housing, etc.) and the like. In particular, when it is used as a member of an IC using mechanism, it is possible to effectively prevent electrical damage or malfunction of the IC due to generation of static electricity.

In addition to excellent moldability, plating,
It is also excellent in secondary workability such as painting and printing, and is suitable for use as a material for large-scale molded products and precision parts, and gives a product with a beautiful appearance.

[0019]

EXAMPLES The present invention will be described in more detail by way of examples, which should not be construed as limiting the invention thereto.

The characteristics of the composition were evaluated as follows. (1) Charging potential (kv) A voltage of 25 kv was applied to the center of the sample plate (150 x 150 x 3 mm) every second for 2 minutes with an electrostatic generator. After the completion of application, at the time of application (initial stage), 10 seconds, 30 seconds, 1 minute, and 10 minutes later, the potential was measured by an electrostatic measurement device and defined as a charging voltage (kv).

(2) Coating property (a) Adhesion property A chemical paint [Micron 3000, manufactured by Cashew Co., Ltd.] was sprayed on a test piece (100 × 100 × 3.2 mm), baked at 80 ° C. for 20 minutes, and dried. After that, 100 squares of 1 mm square were made with a sharp cutter and peeled off with cellophane tape, and x / 100 value was obtained (x: remaining number of squares).

(B) Appearance The appearance after coating was visually observed and evaluated according to the following criteria. ◯: Beautiful Δ: Partially unevenness of filler X: Significant unevenness of filler

(3) Moldability In the case of ABS resin system, M under the condition of 200 ° C. and 5 kg load
I (g / 10 minutes) was calculated, and in the case of polycarbonate resin system, MI under the conditions of 275 ° C. and 2.16 kg load.
(G / 10 minutes) was determined.

The raw materials used for preparing the composite material are shown below. (1) ABS resin ABS-1: manufactured by Japan Synthetic Rubber Co., Ltd., JSR-21 ABS-2: manufactured by Japan Synthetic Rubber Co., Ltd., JSR-35 ABS-3: manufactured by Japan Synthetic Rubber Co., Ltd., JSR-38

(2) Polycarbonate resin PC-1: A-2200 manufactured by Idemitsu Petrochemical Co., Ltd. PC-2: A-2500 manufactured by Idemitsu Petrochemical Co., Ltd.

(3) Zinc oxide powder ZnO-1: manufactured by Shiramizu Chemical Co., Ltd., conductive ZnO, average particle size 3 μm ZnO-2: manufactured by Shiramizu Chemical Co., conductive ZnO, average particle size 0.05 μm ZnO-3 : Shiramizu Chemical Co., Ltd., conductive ZnO, average particle size 8 μm ZnO-4: Shiramizu Chemical Co., Ltd., conductive ZnO, average particle size 15 μm ZnO-5: Shiramizu Chemical Co., general-purpose ZnO, average particle size 3 μm

(4) Carbon Fiber CF-1: Mitsubishi Kasei Co., Ltd., fiber length 3 mm CF-2: Mitsubishi Kasei Co., Ltd., fiber length 1 mm CF-3: Mitsubishi Kasei Co., Ltd., fiber length 6 mm CF-4: manufactured by Mitsubishi Kasei Co., Ltd., fiber length 10 mm

Examples 1 to 27, Comparative Examples 1 to 10 The compounding compositions shown in Tables 1 and 3 were used as twin screw extruders [PCM-4.
5, manufactured by Ikegai Tekko Co., Ltd.] and melt-kneaded to prepare pellets for evaluation. The melt-kneading temperature was set to 210 to 220 ° C in the case of the ABS material, and the melt-kneading temperature was set to 260 to 280 ° C in the case of the polycarbonate resin material.

The evaluation results are shown in Tables 2 and 4.

[0030]

[Table 1]

[0031]

[Table 2]

[0032]

[Table 3]

[0033]

[Table 4]

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hideo Okawa 1 277 Izumicho, Kanda, Chiyoda-ku, Tokyo Inside Calup Industry Co., Ltd.

Claims (1)

[Claims] 1. (A) ABS resin or polycarbonate or 55 to 92% by weight of a mixture thereof, (B)
A charge-sustaining composite material comprising 5 to 30% by weight of zinc oxide powder having an average particle size of 0.1 to 10 μm and (C) 3 to 15% by weight of carbon fiber having a fiber length of 2 to 8 mm.