WO2014002581A1

WO2014002581A1 - Synthetic resin composition and moulded body

Info

Publication number: WO2014002581A1
Application number: PCT/JP2013/061061
Authority: WO
Inventors: 大関実; 畠慎也
Original assignee: 株式会社クレファイン
Priority date: 2012-06-27
Filing date: 2013-04-12
Publication date: 2014-01-03
Also published as: JPWO2014002581A1; TW201404813A

Abstract

A synthetic resin composition containing: 46-99.4 mass% of synthetic resin (A); 0.5-40 mass% of a carbon precursor (B) having a volume resistivity of 10²-10¹⁰Ω∙cm; and 0.1-14 mass% of at least one type of conductive filler (C) selected from carbon nanotubes and carbon nanofibres having a volume resistivity of less than 10²Ω∙cm. A moulded body formed by moulding the synthetic resin composition, and a moulded body which serves as a tray or vessel for conveying an electronic device.

Description

Synthetic resin composition and molded body

The present invention relates to a synthetic resin composition, and more specifically, a synthetic resin composition capable of strictly controlling the surface resistivity to a desired value in a semiconductive region and generating a very small amount of foreign particles (particles). Related to things.

The present invention also relates to a molded body formed by molding this synthetic resin composition. The molded body formed by molding the synthetic resin composition of the present invention can cope with ESD failures such as electrostatic discharge phenomenon (Electro-Static Discharge) and electrostatic breakdown (Electro-Static Destroy) caused thereby, and Since it is low-polluting, it can be suitably applied to a wide range of fields that require control of static electricity, prevention of charging, electromagnetic shielding, prevention of dust adsorption, and the like. Therefore, the present invention particularly relates to a molded body such as a transfer tray or container for an electronic device such as a semiconductor device.

Components used in the manufacturing process of semiconductors such as IC and LSI and mounting parts thereof, components used in the manufacturing process of magnetic heads and hard disk drives and mounting parts thereof, components used in the manufacturing process of liquid crystal displays and the like Resin materials used for molding mounted parts and the like are required to have excellent mechanical properties, heat resistance, chemical resistance, and dimensional stability. These components include, for example, trays and containers used for transportation (including transportation) in the manufacturing process of electronic devices. Such trays and containers include, for example, wafer carriers, cleaning trays, IC chip trays, trays or containers for transporting hard disk drive components, particularly magnetic head trays and head gimbal assemblies (HGA). ) There are trays.

Conventionally, as a resin material in this technical field, for example, polyether ether ketone, polyether imide, polysulfone, polyether sulfone, polyphenylene sulfide and the like are excellent in mechanical properties, heat resistance, chemical resistance, etc., so-called engineering plastics Synthetic resins belonging to are used.

In recent years, high-density pitches of electronic devices have been rapidly developed, including the remarkable increase in recording density of hard disk drives. In the electronic device manufacturing process, when a component formed of a resin material having a surface resistivity exceeding 10 ¹³ Ω / □ is used, the electronic device is easily charged due to the effect of frictional charging of the component. An electronic device that is charged and accumulates static electricity may cause trouble due to damage caused by electrostatic discharge or electrostatic adsorption of dust floating in the air. On the other hand, if a part made of a resin material having a surface resistivity of less than 10 ⁵ Ω / □ is used, the charge movement speed in the resin part is too high, and a strong current generated during electrostatic discharge or high Voltage can cause damage to electronic devices.

From the standpoint of protecting electronic devices from electrostatic disturbances and maintaining a high degree of cleanliness without bringing in dust, the parts used in these technical fields have a surface resistivity of 10 ⁵ ˜ Control within the range of 10 ¹² Ω / □ is required. Therefore, conventionally, there has been proposed a method for obtaining a molded body having a surface resistivity in a semiconductive region by using a resin material containing an antistatic agent or a conductive filler.

However, the method of adding an antistatic agent to the resin material tends to lose the antistatic effect because the antistatic agent present on the surface of the molded body is removed by washing or friction. If the amount of the antistatic agent is increased so that the antistatic agent can easily bleed from the inside of the molded body to the surface, the antistatic effect can be maintained to some extent, but the bleeded antistatic agent can be applied to the surface of the molded body. Electronic devices and the environment are contaminated by dust adhering, and elution and volatilization of the antistatic agent. In addition, when a large amount of the antistatic agent is blended, the heat resistance of the molded product is lowered.

In addition, the method of blending the resin material with a conductive filler having a volume resistivity of less than 10 ² Ω · cm, such as conductive carbon black or carbon fiber, greatly increases the electrical resistivity of the resin material and the conductive filler. For this reason, the surface resistivity of the obtained molded body varies greatly depending on the mixing ratio of the conductive filler and the slight variation in the molding conditions. Therefore, in the method of simply blending the conductive filler, the surface resistivity of the obtained molded body can be strictly and stably controlled so as to be a desired value within the range of 10 ⁵ to 10 ¹² Ω / □. It is extremely difficult. Moreover, in the method of blending the conductive filler, large variations are likely to occur in the surface resistivity at each location of the molded body. A molded product with a large variation in surface resistivity has a mixture of places where the surface resistivity is too large and too small. For example, if it is used as a tray or container for transporting electronic device parts, it is sufficiently resistant to ESD damage. I can't respond.

In order to solve the above problem, as Patent Document 1, synthetic resin 1 to 55% by mass, volume resistivity 10 ² to 10 ¹⁰ Ω · cm of carbon precursor 45 to 99% by mass, and volume resistivity 10 ² Ω · A semiconductive resin composition containing 0 to 30% by mass of a conductive filler of less than cm is proposed, and in this field, functions such as static electricity control, antistatic, electromagnetic wave shielding, and dust adsorption prevention are required. It is disclosed that it can be suitably used as various molded articles, parts, members and the like.

Patent Document 2 discloses a carbon precursor 5 to 30 to 94% by mass of a thermoplastic resin component containing a crystalline thermoplastic resin and an amorphous thermoplastic resin and having a volume resistivity of 10 ² to 10 ¹⁰ Ω · cm. An injection molded body formed by molding a resin composition containing 40% by mass and 1 to 30% by mass of a conductive filler having a volume resistivity of less than 10 ² Ω · cm has been proposed. There are disclosed low-contamination injection-molded articles with little variation in surface resistivity.

Further, as Patent Document 3, synthetic resin 46 to 98.5% by weight, volume resistivity 10 ² to 10 ¹⁰ Ω · cm of carbon precursor 1 to 40% by weight, and volume resistivity less than 10 ² Ω · cm. A synthetic resin composition containing 0.5 to 14% by weight of carbon fiber and a molded product formed by molding the synthetic resin composition are proposed, whereby the surface resistivity is a desired value in the semiconductive region. It can be strictly controlled, and when a synthetic resin composition is formed into a molded product by blending carbon fibers in a relatively small proportion, a molded product with extremely small variation in surface resistivity depending on the location is obtained. It is disclosed that it is possible.

In these patent documents, as synthetic resins or thermoplastic resins, thermoplastic polyesters such as polybutylene terephthalate, polyarylene sulfides such as polyetheretherketone and polyphenylene sulfide, polyolefins such as polypropylene, polycarbonate, polyetherimide, polyethersulfone Polyacetal, fluororesin, epoxy resin and the like are disclosed.

Patent Documents 1 and 2 exemplify carbon fiber, graphite, conductive carbon black, metal fiber, metal powder, and the like as the conductive filler having a volume resistivity of less than 10 ² Ω · cm. From the viewpoint of controllability and reproducibility of the rate or surface resistivity, carbon fiber, graphite, conductive carbon black, and mixtures thereof are preferred, and carbon fiber is particularly preferred. Furthermore, as a specific example, Patent Document 1 describes a resin composition containing 30% by mass of polybutylene terephthalate, 65% by mass of a carbon precursor, and 5% by mass of carbon fiber, and Patent Document 2 describes a thermoplastic resin. Injection formed by molding a resin composition containing 59.0 to 66.0% by mass of component, 15.0 to 16.0% by mass of carbon precursor, and 18.0 to 25.0% by mass of PAN-based carbon fiber A molded article is described, and Patent Document 3 describes a synthetic resin composition containing 65 to 75% by weight of a synthetic resin, 20 to 28% by weight of a carbon precursor, and 5 to 10% by weight of a PAN-based carbon fiber. Yes. The carbon fibers described in these patent documents have an average fiber length of 20 μm to 0.1 mm.

Although the present inventors can obtain a molded body in which the surface resistivity is controlled within a desired range by making the resin composition disclosed in the above patent document into a molded body by injection molding or the like, It has been found that there is a problem that the amount of foreign particles (particles) generated from the molded body is large.

Parts such as transport trays and containers used in the manufacturing process of electronic devices such as hard disk drives (HDD) are used in clean rooms. Become. These parts are often used in a cleaning process with ultrapure water or a solvent after mounting or housing an electronic device or the like, or are used after being cleaned themselves. If the amount of particles generated in these parts is large, the electronic device is contaminated in the cleaning process, or the cleaning liquid is contaminated.

When an electronic device is contaminated with particles, it adversely affects the electrical characteristics, reliability, product yield, etc. of the electronic device. When the cleaning liquid is contaminated with particles, it becomes difficult to repeatedly use the cleaning liquid, and it is necessary to frequently purify the cleaning liquid.

In addition to increasing the density of electronic devices, as the manufacturing process speeds up, the surface resistivity of the molded body that is a component such as a transport tray or container used in the manufacturing process is within the desired range of the semiconductive region. In addition, there is a need for further improvement in electrical characteristics such as strictly controlled and extremely small variation in surface resistivity, and further improvement in low pollution that further reduces the amount of particles generated. I came.

Japanese Patent Laid-Open No. 2002-121402 JP 2005-290328 A JP-T 2002-53660 (corresponding to International Publication No. 00/34369)

The subject of the present invention is a synthetic resin in which the surface resistivity is strictly controlled within a desired range of the semiconductive region, the variation of the surface resistivity is extremely small, and the generation amount of foreign particles (particles) is extremely small. It is to provide a composition.

Moreover, the subject of this invention is providing the molded object which was excellent in the electrical property formed by shape | molding this synthetic resin composition, especially the molded object which is a tray, a container, etc. for electronic devices, such as a semiconductor device. It is in.

As a result of intensive studies to achieve the above-mentioned problems, the present inventors have found that in a synthetic resin composition containing a synthetic resin, a carbon precursor, and a conductive filler, carbon nanotubes and / or as conductive fillers are used. The inventors have found that the problems can be solved by selecting carbon nanofibers and forming a synthetic resin composition containing these in a specific ratio, and the present invention has been completed.

That is, according to the present invention, the synthetic resin (A) is 46 to 99.4 mass%, the volume resistivity is 10 ² to 10 ¹⁰ Ω · cm, the carbon precursor (B) is 0.5 to 40 mass%, and the volume is There is provided a synthetic resin composition containing 0.1 to 14% by mass of at least one conductive filler (C) selected from carbon nanotubes and carbon nanofibers having a resistivity of less than 10 ² Ω · cm.

According to the present invention, as an embodiment, the synthetic resin (A) is a thermoplastic polyester, polyarylene sulfide, polyolefin, polycarbonate, polyether ether ketone, polyacetal, polyether imide, polyether sulfone, fluororesin, And the above synthetic resin composition that is at least one selected from the group consisting of epoxy resins.

Furthermore, according to the present invention, there is provided a molded body obtained by molding any one of the above synthetic resin compositions.

According to the present invention, the following molded articles (1) to (6) are provided as embodiments.
(1) Any one of the above-mentioned molded bodies which is an injection molded body or an extruded molded body.
(2) Any one of the above-mentioned molded products, wherein the number of particles having a particle size of 0.5 μm or more measured in pure water is 2,000 particles / cm ³ or less.
(3) The molded article according to any one of the above, wherein the variation in the surface resistivity represented by the ratio (Max / Min) between the maximum surface resistivity (Max) and the minimum surface resistivity (Min) is 1,000 or less.
(4) The molded article according to any one of the above, which is a tray or a container for transporting an electronic device.
(5) The molded article according to any one of the above, which is a transport tray or container for hard disk drive components.
(6) The molded article according to any one of the above, which is a magnetic head tray or a head gimbal assembly (HGA) tray.

According to the present invention, the synthetic resin (A) 46 to 99.4 mass%, the volume resistivity 10 ² to 10 ¹⁰ Ω · cm of the carbon precursor (B) 0.5 to 40 mass%, and the volume resistivity By being a synthetic resin composition containing 0.1 to 14% by mass of at least one conductive filler (C) selected from carbon nanotubes and carbon nanofibers of less than 10 ² Ω · cm, the surface resistivity is half There is an effect that a synthetic resin composition is provided that is strictly controlled within a desired range of the conductive region, has a very small variation in surface resistivity, and has an extremely small amount of generation of foreign particles (particles). The

Further, according to the present invention, the surface resistivity is strictly controlled within a desired range of the semiconductive region, and the surface resistivity is obtained by molding the synthetic resin composition. Can be obtained, and a molded body with a very small amount of generation of foreign particles can be obtained. Therefore, a tray or container for electronic devices having excellent characteristics, especially a tray for transporting hard disk drive components. Alternatively, it is possible to provide a container, in particular, a magnetic head tray or a head gimbal assembly (HGA) tray.

1. Synthetic resin (A)
The synthetic resin (A) contained in the synthetic resin composition of the present invention is not particularly limited, but is preferably a synthetic resin that can form a molded body such as an injection molded body or an extrusion molded body. Polyamide, polyacetal, thermoplastic polyester, polyolefin (eg, polyethylene, polypropylene, polybutene, polyisobutylene, etc.), polyvinyl chloride, polyvinylidene chloride, poly-p-xylene, polycarbonate, modified polyphenylene ether, polyurethane, polydimethylsiloxane, polystyrene , ABS resin, polymethyl methacrylate, polyarylene sulfide, polyether ether ketone, polyether ketone, polyarylene sulfide ketone, polyarylene sulfide sulfone, polyether nitrile, wholly aromatic Riesuteru, fluororesin, polyarylate, polysulfone, polyether sulfone, polyetherimide, polyamideimide, polyimide, polyaminobismaleimide, diallyl terephthalate resin, triazine resin, epoxy resin, phenol resin, etc. modified products thereof.

From the viewpoint of obtaining a molded product with extremely small particle generation and extremely small variation in surface resistivity, thermoplastic polyesters such as polybutylene terephthalate and polyethylene terephthalate; polyarylene sulfides such as polyphenylene sulfide; polypropylene and the like A synthetic resin (A) which is at least one selected from the group consisting of polyolefins, polycarbonates, polyether ether ketones, polyacetals, polyether imides, polyether sulfones, fluororesins, and epoxy resins is more preferably used. These synthetic resins can be used alone or in admixture of two or more. Note that the epoxy resin may be an epoxy resin alone or, if necessary, a composition containing a curing agent.

Particularly preferred synthetic resin (A) is polyetheretherketone; polyarylene sulfide; polyetherimide; polyethersulfone; polycarbonate; or epoxy resin. Although these synthetic resins (A) may prepare a polymer, a commercial item may be used and a commercial item may be mixed and used. For example, polyether ether ketone is a trade name “VICTREX (registered trademark) PEEK450P” manufactured by Victrex, and polyarylene sulfide is a product name “Fortron (registered trademark) W214A” manufactured by Polyplastics Co., Ltd. The polyetherimide is a product name “Ultem (registered trademark) 1010” manufactured by GE Plastics, and the polyethersulfone is a product name “Sumika Excel (registered trademark) PES3600G” manufactured by Sumitomo Chemical Co., Ltd. Polycarbonate is commercially available under the trade name “Panlite (registered trademark) L-1225W” manufactured by Teijin Chemicals Ltd., and epoxy resin is commercially available under the product name “JER (registered trademark) YX4000HK” manufactured by Mitsubishi Chemical Corporation. Goods can be obtained.

In the synthetic resin composition of the present invention, the content of the synthetic resin (A) is 46 to 99.4% by mass, preferably 70 to 99% by mass, more preferably 74 to 98.5% by mass, and still more preferably. Is 77-98.2 mass%. In addition, let the total amount of the content rate of a synthetic resin (A), the carbon precursor (B) mentioned later, and an electroconductive filler (C) be 100 mass%.

When the content ratio of the synthetic resin (A) is too large, the surface resistivity of the molded body increases, and it becomes difficult to control the surface resistivity of the desired semiconductive region. On the other hand, if the content ratio of the synthetic resin (A) is too small, the surface resistivity of the molded body becomes too low, and it becomes difficult to control the surface resistivity of the desired semiconductive region. Insulation properties are too low.

2. Carbon precursor (B)
The carbon precursor (B) having a volume resistivity of 10 ² to 10 ¹⁰ Ω · cm contained in the synthetic resin composition of the present invention is obtained by baking an organic substance at a temperature of 400 to 900 ° C. in an inert atmosphere. It can be obtained by doing.

More specifically, the carbon precursor (B) contained in the synthetic resin composition of the present invention includes, for example, (i) heating tar or pitch such as petroleum tar, petroleum pitch, coal tar, coal pitch, etc. Performing grouping and polycondensation, and if necessary, oxidizing and infusifying in an oxidizing atmosphere, followed by heating and firing in an inert atmosphere, (ii) oxidizing thermoplastic resins such as polyacrylonitrile and polyvinyl chloride By a method of infusibilizing in an atmosphere and further heating and baking in an inert atmosphere, (iii) a method of heating and baking a thermosetting resin such as a phenol resin and a furan resin, and then heating and baking in an inert atmosphere Can be manufactured.

The carbon precursor (B) contained in the synthetic resin composition of the present invention means a substance that is not completely carbonized and has a carbon content of 97% by mass or less obtained by these treatments. When the organic substance is heated and fired in an inert atmosphere, the carbon content of the fired body obtained increases as the firing temperature rises. The carbon content of the carbon precursor (B) contained in the synthetic resin composition can be controlled by appropriately setting the firing temperature. The carbon precursor (B) having a volume resistivity of 10 ² to 10 ¹⁰ Ω · cm used in the present invention preferably has a carbon content of preferably 80 to 97% by mass, more preferably 85 to 96.5% by mass. It can be obtained as a carbon precursor (B) that is not carbonized.

When the carbon content of the carbon precursor (B) is too small, the volume resistivity becomes too high, and it is difficult to make the surface resistivity of the molded body obtained from the synthetic resin composition 10 ¹³ Ω / □ or less. Become. Therefore, the volume resistivity of the carbon precursor (B) is 10 ² to 10 ¹⁰ Ω · cm, preferably 10 ³ to 10 ⁹ Ω · cm.

Carbon precursor (B) is usually used in the form of particles or fibers. The average particle diameter of the carbon precursor (B) particles contained in the synthetic resin composition of the present invention is preferably 1 mm or less. When the average particle diameter of the carbon precursor (B) is too large, it is difficult to obtain a molded article having a good appearance when molding the synthetic resin composition. The average particle diameter of the carbon precursor (B) particles is usually 0.1 μm to 1 mm, preferably 0.5 to 500 μm, more preferably 1 to 100 μm. In many cases, good results can be obtained by using the carbon precursor (B) having an average particle diameter of about 5 to 50 μm. The average diameter of the fibrous carbon precursor (B) used in the present invention is preferably 0.1 mm or less. If the average diameter of the fibrous carbon precursor (B) exceeds 0.1 mm, it is difficult to obtain a molded article having a good appearance. The fibrous carbon precursor (B) is preferably a short fiber from the viewpoint of dispersibility in the synthetic resin composition.

In the synthetic resin composition of the present invention, the content of the carbon precursor (B) is 0.5 to 40% by mass, preferably 1 to 30% by mass, more preferably 5 to 25% by mass, and still more preferably. 10 to 20% by mass. When the content ratio of the carbon precursor (B) is too large, the mechanical properties of a molded body obtained by molding the synthetic resin composition may be deteriorated. On the other hand, if the content ratio of the carbon precursor (B) is too small, it is difficult to sufficiently reduce the surface resistivity of the molded product obtained by molding the synthetic resin composition, or there is variation due to the location of the surface resistivity. There is a tendency to become larger. Depending on the type of the synthetic resin, a sufficient effect may be obtained when the content of the carbon precursor (B) is about 1.2 to 5% by mass.

3. Conductive filler (C)
Synthetic resin composition of the present invention is characterized in that it contains a predetermined amount of at least one conductive filler (C) is selected from carbon nanotubes and carbon nanofibers is less than a volume resistivity of 10 ² Ω · cm.

In the present invention, the carbon nanotubes and carbon nanofibers used as the conductive filler (C) belong to carbon fine fibers, and the carbon layer is a single layer whose carbon hexagonal mesh surface is closed in a cylindrical shape. There is a multilayer structure in which a cylindrical carbon layer is nested, and the structure is not limited to any one. When preparing a synthetic resin composition or forming a molded body from a synthetic resin composition, multi-walled carbon nanotubes with high bending strength are often preferred because they are not easily damaged by shear stress. The carbon nanotubes and carbon nanofibers used in the present invention have an average fiber diameter of usually 0.5 to 200 nm, preferably 2 to 50 nm, more preferably 5 to 20 nm, and an average fiber length of usually 100 nm to 15 μm, The thickness is preferably from 150 nm to 10 μm. When the average fiber diameter is less than 0.5 nm, uniform dispersion in the synthetic resin composition is difficult, and when preparing the synthetic resin composition or forming a molded body from the synthetic resin composition, shearing is performed. May be damaged by stress. If the average fiber diameter exceeds 200 nm, the fine dispersion effect that is characteristic of fine fibers may not be obtained. On the other hand, if the average fiber length is less than 100 nm or exceeds 15 μm, uniform dispersion in the synthetic resin composition becomes difficult, and desired electrical characteristics may not be obtained. The aspect ratio (L / D) obtained by dividing the average fiber length (L) by the average fiber diameter (D) is preferably 10 or more, more preferably 50 or more, and still more preferably 100 or more. The method for producing carbon nanotubes and carbon nanofibers used in the present invention is not particularly limited, and a method of causing arc discharge between the carbon electrodes to grow on the cathode surface of the discharge electrode, or irradiating silicon carbide with a laser beam. Thus, it is produced by a method of heating and sublimation, a method of carbonizing a hydrocarbon in a gas phase under a reducing atmosphere using a transition metal catalyst, and the like. The shape and size of the carbon nanotube obtained by the manufacturing method are different. In the carbon nanotube, the graphite layer is substantially parallel to the fiber axis. On the other hand, carbon fine fibers produced by the vapor phase method are not hollow, or have a structure in which the graphite layer is inclined with respect to the fiber axis, and those substantially perpendicular to the fiber axis. There are also blurry ones, which are called carbon nanofibers. Carbon nanotubes and carbon nanofibers are, for example, VGCF (registered trademark) series manufactured by Showa Denko KK, Nanocyl (registered trademark) series manufactured by Nanosil, AMC (registered trademark) series manufactured by Ube Industries, Ltd., Bayer Commercially available products such as BAYTUBE (registered trademark) series are available.

Since carbon nanotubes and carbon nanofibers are almost completely carbonized substances having a carbon content exceeding 97% by mass, the volume resistivity is usually less than 10 ² Ω · cm (in many cases 10% ^-2 Ω · cm or less is well known). Therefore, the synthetic resin composition of the present invention contains at least one conductive filler (C) selected from carbon nanotubes and carbon nanofibers having a volume resistivity of less than 10 ² Ω · cm. is there. The conductive filler (C) has a volume resistivity of less than 10 ² Ω · cm, and the carbon precursor (B) has a volume resistivity of 10 ² to 10 ¹⁰ Ω · cm. Yes).

In addition, the carbon fiber that has been widely used as a conductive filler conventionally has an average fiber length of 20 μm or more, so the conductive filler (C) contained in the synthetic resin composition of the present invention, that is, At least one conductive filler (C) selected from carbon nanotubes and carbon nanofibers having a volume resistivity of less than 10 ² Ω · cm can also be distinguished from the carbon fibers. Furthermore, similarly, the conductive filler (C) can be distinguished from graphite and conductive carbon black, which have been widely used as a conductive filler.

In the synthetic resin composition of the present invention, the content of the conductive filler (C) is 0.1 to 14% by mass, preferably 0.15 to 10% by mass, more preferably 0.2 to 8% by mass. %, More preferably 0.3 to 6% by mass. The synthetic resin composition of the present invention can contain one or both of carbon nanotubes or carbon nanofibers having a volume resistivity of less than 10 ² Ω · cm. Synthetic resin composition of the present invention, when containing both carbon nanofiber carbon than nanotubes and a volume resistivity of 10 ² Ω · cm under a volume resistivity of 10 ² Ω · cm, the conductive filler ( The content ratio of C) means the total content ratio of carbon nanotubes and carbon nanofibers. If the content ratio of the conductive filler (C) is too large, i) the surface resistivity of the molded body formed by molding the synthetic resin composition becomes too low, and the surface resistivity of the molded body is reduced within the semiconductive region. It is difficult to control the surface resistivity of the molded body, ii) the surface resistivity varies depending on the location on the surface of the molded body, iii) and the molded body formed by molding the synthetic resin composition. Mechanical properties may be degraded. When the content ratio of the conductive filler (C) is too small, it becomes difficult to control the surface resistivity of the molded body formed by molding the synthetic resin composition to the surface resistivity in the semiconductive region.

The synthetic resin composition of the present invention contains at least one conductive filler (C) selected from carbon nanotubes and carbon nanofibers having a volume resistivity of less than 10 ² Ω · cm, for example, 0.4 to 5.5 mass. %, And in combination with a carbon precursor (B) having a volume resistivity of 10 ² to 10 ¹⁰ Ω · cm, a molding formed by molding the synthetic resin composition The body can have excellent surface resistivity controllability and mechanical properties. Therefore, according to this invention, it becomes possible to increase content of the synthetic resin (A) contained in the synthetic resin composition and the molded body formed by molding the synthetic resin composition. As a result, the synthetic resin composition of the present invention and the molded article formed by molding the synthetic resin composition can sufficiently exhibit the mechanical characteristics and other characteristics of the synthetic resin (A). This increases the degree of freedom in product design and contributes to cost reduction.

4). Other fillers In the synthetic resin composition of the present invention, the purpose is to further increase the mechanical strength and heat resistance of a molded article obtained by molding the synthetic resin composition within the range not impairing the object of the present invention. Various other fillers can be contained. Examples of the filler include inorganic fibers such as glass fiber, asbestos fiber, silica fiber, alumina fiber, zirconia fiber, boron nitride fiber, silicon nitride fiber, boron fiber, potassium titanate fiber; polyamide, fluororesin, polyester Examples thereof include fibrous fillers such as high melting point organic fibrous materials such as resins and acrylic resins. The fibrous filler is preferably a non-conductive material such as glass fiber from the viewpoint of electrical insulation.

Examples of the filler include mica, silica, talc, alumina, kaolin, calcium sulfate, calcium carbonate, titanium oxide, ferrite, clay, glass powder, zinc oxide, nickel carbonate, iron oxide, quartz powder, magnesium carbonate, A granular or powder filler such as barium sulfate can be used.

These fillers can be used alone or in combination of two or more. The filler may be treated with a sizing agent or a surface treatment agent as necessary. Examples of the sizing agent or surface treatment agent include functional compounds such as epoxy compounds, isocyanate compounds, silane compounds, and titanate compounds. These functional compounds may be used after being subjected to surface treatment or focusing treatment on the filler in advance, or may be added simultaneously when preparing the synthetic resin composition. Since these other fillers are contained in the synthetic resin composition within a range not impairing the object of the present invention, the content thereof is usually within 5% by mass, and often within 1% by mass. In most cases, the amount is within 0.5% by mass, and the synthetic resin composition may contain no other filler.

5. Other Additives In the synthetic resin composition of the present invention, as other additives, for example, an impact modifier such as an epoxy group-containing α-olefin copolymer, within the range not impairing the object of the present invention; Resin modifiers such as ethylene glycidyl methacrylate; Mold corrosion inhibitors such as zinc carbonate and nickel carbonate; Lubricants such as pentaerythritol tetrastearate; Thermosetting resins; Antioxidants; Ultraviolet absorbers; Cores such as boron nitride Agents; flame retardants; colorants such as dyes and pigments; and the like can be added as appropriate. The content of these other additives is usually within 5% by mass, in many cases within 1% by mass, and in most cases within 0.5% by mass, and it does not matter if it is not contained.

6). Synthetic Resin Composition The synthetic resin composition of the present invention may have any shape or form as long as it contains a predetermined amount of each component of the synthetic resin (A), the carbon precursor (B), and the conductive filler (C). Absent. For example, it may be a molded body, a laminate, a liquid such as a melt, or may be in the form of pellets, particles, powder, granules, aggregates, or the like. For example, the pellet which is the synthetic resin composition of the present invention can be prepared by facilities and methods generally used in the preparation of the synthetic resin composition. That is, each component is premixed with a Henschel mixer, tumbler, etc., and if necessary, other fillers such as glass fibers are added and further mixed, and then kneaded using a single or twin screw extruder. Then, the pellets for molding can be obtained by extruding. At that time, a part of the necessary components is made into a master batch and then mixed with the remaining components. In addition, in order to improve the dispersibility of each component, a part of the raw materials to be used is pulverized and mixed with a uniform particle size. It is also possible to employ a method of melt extrusion.

7). Molded body formed by molding synthetic resin composition and method for producing the same The molded body formed by molding the synthetic resin composition of the present invention includes the synthetic resin (A), carbon precursor (B), and conductive filler. The synthetic resin composition containing a predetermined amount of each component of (C) can be obtained by molding by a molding method usually employed as a molding method of the synthetic resin composition. The synthetic resin composition is preferably used in the form of pellets described above.

As a molding method for obtaining a molded body formed by molding the synthetic resin composition, injection molding, extrusion molding, compression molding, vacuum molding, pressure molding, blow molding, stretch molding, melt spinning, etc. can be employed. . Therefore, as a molded body formed by molding the synthetic resin composition of the present invention, an injection molded body, an extrusion molded body, a compression molded body, a vacuum molded body, a compressed air molded body, a blow molded body, a stretch molded body, or a fiber , Yarn or fabric.

Furthermore, the molded body formed by molding the synthetic resin composition of the present invention may have, for example, a through hole or a concave hole on the surface for mounting or mounting the electronic device. In that case, the shape, size, and number of the through holes and the recessed holes can be appropriately set depending on the purpose of use. The diameter of the through hole or the concave hole is usually about 0.1 to 1.0 mm, preferably about 0.2 to 0.8 mm, more preferably about 0.3 to 0.7 mm, and the number is the area of the molded body. It is about 100 to 2,000, preferably 200 to 1,500, and more preferably about 300 to 750 in terms of 50 mm × 50 mm. For example, when the synthetic resin composition of the present invention is injection-molded, the molded body having a through-hole or a concave hole is a mold in which a large number of pins are implanted on a cavity surface or a metal in which a large number of convex portions are engraved. By using a mold, it can be easily manufactured.

As the molded article formed by molding the synthetic resin composition of the present invention, an injection molded article or an extruded molded article is preferably selected from the viewpoint of utilizing excellent electrical characteristics such as surface resistivity and mechanical characteristics. The injection molding or extrusion molding method for obtaining an injection molded body or an extrusion molded body can be performed according to normal molding conditions. For example, injection molding can be performed by appropriately adjusting the cylinder temperature, mold temperature, etc. of the injection molding machine according to the type of synthetic resin to be used in accordance with general injection molding conditions.

8). Particle Generation Amount of Molded Body A molded body formed by molding the synthetic resin composition of the present invention is a molding in which the number of particles generated with a particle size of 0.5 μm or more measured in pure water is 2,000 particles / cm ³ or less. More preferably 1,700 pieces / cm ³ or less, still more preferably 1,500 pieces / cm ³ or less, particularly preferably 1,000 pieces / cm ³ or less, Depending on the selection of the synthetic resin (A), it can be 600 pieces / cm ³ or less, so that contamination due to generation of particles (that is, foreign particles) can be remarkably suppressed. The amount of particles having a particle diameter of 0.5 μm or more measured in pure water is not particularly limited and is most preferably 0 / cm ³ , but is usually about 2 / cm ³ , and in many cases 5 / It can be about cm ³ .

The amount of particles generated in pure water of a molded product obtained by molding the synthetic resin composition is a value measured by the following measurement method (hereinafter, simply referred to as “particle generation amount of molded product”). . That is, after 500 cm ³ of pure water is poured into a 500 cm ³ beaker in advance, it is vibrated for 1 minute with an ultrasonic oscillator (1,200 W). The amount of particles generated in the pure water after the vibration treatment is measured using a submerged particle counter to obtain a ground value. Then, the injection molded plate and the synthetic resin composition was prepared by injection molding (50mm × 50mm × 2mm thick), placed in a 500 cm ³ beaker, deionized water 500 cm ³ injected, vibrated at the same conditions as the above-described processing The amount of particles generated in the pure water after the measurement is measured using a submerged particle counter, and the ground value is subtracted to obtain the amount of particles generated in the molded body. In the present invention, the number of particles having a particle size of 0.5 μm or more, the number of particles having a particle size of 1.0 μm or more, and the number of particles having a particle size of 2.0 μm or more are obtained. The unit is expressed in pieces / cm ³ .

9. Surface resistivity of molded body A molded body formed by molding the synthetic resin composition of the present invention has a surface resistivity of 10 ⁵ to 10 ¹² Ω / □, which is a semiconductive region, and preferably 1.1 ×. 10 ⁵ to 9.9 × 10 ¹¹ Ω / □, more preferably 1.2 × 10 ⁵ to 9 × 10 ¹¹ Ω / □, more preferably 1.5 × 10 ⁵ to 8 × 10 ¹¹ Ω / □ Has resistivity. The surface resistivity represents the resistance per unit surface area, and the unit is Ω. However, in order to distinguish it from mere resistance, in the present invention, it is expressed by Ω / □ (ohm per square).

The surface resistivity of a molded article formed by molding the synthetic resin composition is measured by the following measurement method. That is, for an injection-molded plate (50 mm × 50 mm × 2 mm thickness) prepared by injection molding a synthetic resin composition, the surface resistivity of five points is measured at an applied voltage of 100 V in accordance with JIS K6911. Let the average value of the measured value of the surface resistivity of 5 points | pieces be the surface resistivity of a molded object. The molded body formed by molding the synthetic resin composition of the present invention has a surface resistivity (that is, an average value of measured values of surface resistivity at 5 points) of 10 ^{5 as described above.} The maximum value [maximum surface resistivity (Max)] and the minimum value [minimum surface resistivity (Min) among the measured values of the surface resistivity at five points are included in the range of ˜10 ¹² Ω / □. )] Is preferably included in the range of 10 ⁵ to 10 ¹² Ω / □, which is the semiconductive region described above.

The molded body formed by molding the synthetic resin composition of the present invention has extremely small variation in surface resistivity due to the difference in the location of the molded body. The variation in the surface resistivity of the molded body can be expressed by the ratio (Max / Min) between the maximum surface resistivity (Max) and the minimum surface resistivity (Min) of the molded body formed by molding the synthetic resin composition. The molded product obtained by molding the synthetic resin composition of the present invention has a surface resistivity variation (Max / Min) of preferably 1,000 or less, more preferably 800 or less, still more preferably. Is 500 or less, particularly preferably 200 or less.

10. Use of molded product formed by molding synthetic resin composition The molded product formed by molding the synthetic resin composition of the present invention may be used as it is or after being subjected to secondary processing such as cutting, drilling or cutting. it can. In the electric / electronic field, for example, a wafer carrier, a wafer cassette, a spin chuck, a tote bottle, a wafer boat, an IC chip tray, IC chip carrier, IC card, IC test socket, burn-in socket, pin grid array socket, quad flat package, leadless chip carrier, dual inline package, small outline package, reel packing, various cases, storage tray, storage bin, Examples include conveyor device parts and magnetic card readers.

In the field of office automation equipment, for example, charging members such as charging rolls, transfer rolls, and developing rolls in image forming apparatuses such as electrophotographic copying machines and electrostatic recording apparatuses, transfer drums for recording apparatuses, printed circuit board cassettes, bushes, paper, Bill transport parts, paper feed rails, font cartridges, ink ribbon canisters, guide pins, trays, rollers, gears, sprockets, computer housings, modem housings, monitor housings, CD-ROM housings, printer housings, connectors, computer slots, etc. Can be mentioned.

In the communication equipment field, mobile phone parts, pagers (receivers), various sliding materials, and the like can be given. In the automotive field, interior materials, under hoods, electronic / electric equipment housings, gas tank caps, fuel filters, fuel line connectors, fuel line clips, fuel tanks, equipment beads, door handles, various parts, and the like. In other fields, electric wire supports, radio wave absorbers, floor materials, pallets, shoe soles, blower fans, planar heating elements, polyswitches, and the like can be given.

11. Electronic device carrying tray or container The molded body formed by molding the synthetic resin composition of the present invention, in particular, components used in the manufacturing process of semiconductors such as IC and LSI, components for mounting the components, magnetic heads and hard disks It can be suitably used as a component used in the manufacturing process of the drive and its mounting component, a component used in the manufacturing process of the liquid crystal display, and its mounting component.

That is, a molded body formed by molding the synthetic resin composition of the present invention is suitably used as a molded body that is a transport tray or container for electronic devices. Examples of the electronic device transfer tray or container include a wafer carrier, a cleaning tray, an IC chip tray, a magnetic head tray for transferring hard disk drive components, and a head gimbal assembly (HGA) tray. Among these, the molded body formed by molding the synthetic resin composition of the present invention can be suitably applied as a transport tray or container for hard disk drive (HDD) parts that are required to avoid contamination extremely. In particular, it can be suitably applied as a magnetic head tray or a head gimbal assembly (HGA) tray.

These trays have, for example, a general-purpose shape such as a thin plate-shaped molded body provided with a large number of through-holes or a planar structure (peripheral portions may be erected so that they can be stacked). In addition, a large number of magnetic heads and HGAs are mounted thereon, and are configured to be transported while being fixed by through holes. When such a molded body is produced by injection molding, in general, burrs are likely to occur in each part including a through hole, and the amount of generated particles increases. In addition, the conventional tray is formed by molding a resin composition containing a large amount of conductive carbon black alone, and the surface resistivity is reduced due to poor dispersion of the conductive carbon black. The variation is large. On the other hand, the molded product obtained by molding the synthetic resin composition of the present invention has a small variation in surface resistivity even with a tray having such a shape, and the generation amount of particles and generation of burrs are remarkable. Will be suppressed.

Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples, but the present invention is not limited to these examples. The measuring method of the physical property or characteristic of a synthetic resin and a molded object is as showing below.

[Melting point or glass transition temperature of synthetic resin]
The melting point or glass transition temperature of the synthetic resin was measured using a differential scanning calorimeter (DSC).

[Surface resistivity of molded body]
The surface resistivity of a molded article formed by molding the synthetic resin composition was measured by the following measurement method. That is, an injection-molded plate (50 mm × 50 mm × 2 mm thickness) prepared by injection molding a synthetic resin composition was applied at a applied voltage of 100 V using Hiresta UP manufactured by Mitsubishi Chemical Analytech Co., Ltd. according to JIS K6911. The surface resistivity at 5 points was measured. The average value of the measured values of the surface resistivity at 5 points was defined as the surface resistivity of the molded body. Further, the ratio (Max / Min) was calculated from the maximum value [maximum surface resistivity (Max)] and the minimum value [minimum surface resistivity (Min)] among the measured values of the surface resistivity at five points.

[Particle generation amount of molded body]
The amount of particles generated in pure water of a molded product formed by molding the synthetic resin composition was measured by the following measurement method. That is, after 500 cm ³ of pure water is poured into a 500 cm ³ beaker in advance, it is vibrated for 1 minute with an ultrasonic oscillator (1,200 W). The amount of particles generated in the pure water after the vibration treatment was measured using a submerged particle counter (KL-30AX, manufactured by Rion Co., Ltd.), and used as a ground value. Then, the injection molded plate and the synthetic resin composition was prepared by injection molding (50mm × 50mm × 2mm thick), placed in a 500 cm ³ beaker, deionized water 500 cm ³ injected, vibrated at the same conditions as the above-described processing The amount of particles generated in the pure water later was measured using an in-liquid particle counter, and the ground value was subtracted to obtain the amount of particles generated in the molded body. The number of particles having a particle size of 0.5 μm or more, the number of particles having a particle size of 1.0 μm or more, and the number of particles having a particle size of 2.0 μm or more were determined. The unit was expressed in pieces / cm ³ .

[Production Example] Production Example of Carbon Precursor A petroleum pitch of 68 kg having a softening point of 210 ° C., a quinoline insoluble content of 1% by mass, and an H / C atomic ratio of 0.63 and naphthalene of 32 kg are mixed with an internal volume of 300 liters having a stirring blade. The mixture was charged into a pressure vessel, heated to 190 ° C., dissolved and mixed, then cooled to a temperature of 80 to 90 ° C. and extruded to obtain a string-like molded body having a diameter of about 500 μm. Next, this string-like molded body was pulverized so that the ratio of diameter to length was about 1.5, and the obtained pulverized product was heated to a temperature of 93 ° C. to a polyvinyl alcohol (kenken) having a concentration of 0.53% by mass. (Degree of conversion 88%) was dropped in an aqueous solution, stirred and dispersed, and then cooled to obtain a spherical pitch formed body.

Subsequently, filtration was performed to remove moisture, and naphthalene remaining in the pitch formed body was extracted and removed with about 6 times as much n-hexane as the spherical pitch formed body. The resulting spherical pitch formed body was oxidized for 1 hour while being heated air at a temperature of 260 ° C. to obtain an oxidized pitch. This oxidized pitch was heat treated (baked) at a temperature of 580 ° C. for 1 hour in a nitrogen stream, and then pulverized to obtain carbon precursor particles having an average particle diameter of about 25 μm. The carbon content of the carbon precursor particles was 91.0% by mass.

The volume resistivity of the carbon precursor was measured by the following method. That is, after the oxidized pitch was pulverized into particles, the particles having a diameter of 100 μm or more were removed by sieving with a mesh having an opening of about 100 μm. 13 g of oxidized pitch powder that passed through the sieve was filled into a cylindrical mold having a cross-sectional area of 80 cm ² and molded at a pressure of 196 MPa to obtain a cylindrical molded body. The cylindrical shaped body was heat treated in a nitrogen stream at a temperature of 580 ° C., which is the same as the heat treatment temperature in the carbon precursor particle production method, for 1 hour, and a volume resistivity measurement sample of the carbon precursor ( Molded body) was obtained. When the volume resistivity of this sample was measured according to JIS K7194, the volume resistivity of the carbon precursor was 3 × 10 ⁷ Ω · cm.

[Example 1]
As shown in Table 1, polyether ether ketone [PEEK; manufactured by Victrex, trade name “VICTREX (registered trademark) PEEK450P”, melting point 334 ° C.] 80.5% by mass, carbon precursor produced by the above production example (volume Resistivity 3 × 10 ⁷ Ω · cm, carbon content 91.0% by mass, hereinafter referred to simply as “carbon precursor” 17.5% by mass, and carbon nanotubes (average fiber diameter 9.5 nm, average fiber A synthetic resin composition consisting of 2.0% by mass (1.5 μm in length) is uniformly dry blended with a tumbler mixer and supplied to a 45 mmφ twin-screw kneading extruder (PCM-45, manufactured by Ikegai Co., Ltd.). To make pellets.

After drying the pellets produced above, injection molding is performed using an injection molding machine (“IS-75” manufactured by Toshiba Machine Co., Ltd.) to form a large number of through holes formed by molding the synthetic resin composition. A thin plate-like injection molded body (50 mm × 50 mm × 2 mm thick injection molded plate) was produced. The injection-molded body had 400 through holes in the thickness direction having a diameter of 0.5 mm per 50 mm × 50 mm area of the injection-molded body. About this injection-molded product, the surface resistivity [average value, ie, the surface resistivity of the molded product, the maximum surface resistivity (Max), the minimum surface resistivity (Min), and the ratio (Max / Min)] and the amount of particles generated Table 1 shows the results of measurement (particle sizes of 0.5 μm or more, 1.0 μm or more, and 2.0 μm or more were counted, respectively).

[Examples 2 and 3]
An injection molded article formed by molding the synthetic resin composition was produced in the same manner as in Example 1 except that the content ratio of each component in the synthetic resin composition was changed as shown in Table 1. Table 1 shows the results of measuring the surface resistivity and the amount of particles generated for this injection-molded product.

[Examples 4 to 6]
Instead of carbon nanotubes, carbon nanofibers (average fiber diameter of 10 to 15 nm, average fiber length of 3 μm) were used, and the content ratio of each component in the synthetic resin composition was changed as shown in Table 1. Except for this, an injection-molded article formed by molding a synthetic resin composition was produced in the same manner as in Example 1. Table 1 shows the results of measuring the surface resistivity and the amount of particles generated for this injection-molded product.

[Example 7]
Instead of PEEK, polyphenylene sulfide [PPS; manufactured by Polyplastics Co., Ltd., trade name “Fortron (registered trademark) W214A”] was used, and the content ratio of each component in the synthetic resin composition An injection molded article formed by molding the synthetic resin composition was produced in the same manner as in Example 1 except that the change was made as shown in 1. Table 1 shows the results of measuring the surface resistivity and the amount of particles generated for this injection-molded product.

[Example 8]
Instead of PEEK, polyetherimide [PEI; manufactured by GE Plastics, trade name “Ultem (registered trademark) 1010”, glass transition temperature 217 ° C.] was used, and each component in the synthetic resin composition was used. An injection molded article formed by molding the synthetic resin composition was produced in the same manner as in Example 1 except that the content ratio was changed as shown in Table 1. Table 1 shows the results of measuring the surface resistivity and the amount of particles generated for this injection-molded product.

[Example 9]
Instead of PEEK, polyether sulfone [PES; manufactured by Sumitomo Chemical Co., Ltd., trade name “Sumika Excel (registered trademark) PES3600G”, glass transition temperature 225 ° C.] was used, and each component in the synthetic resin composition An injection molded body formed by molding a synthetic resin composition was produced in the same manner as in Example 1 except that the content ratio was changed as shown in Table 1. Table 1 shows the results of measuring the surface resistivity and the amount of particles generated for this injection-molded product.

[Example 10]
Instead of PEEK, polycarbonate [PC; manufactured by Teijin Chemicals Ltd., trade name “Panlite (registered trademark) L-1225W”, glass transition temperature 150 ° C.] was used, and each component in the synthetic resin composition An injection molded body formed by molding a synthetic resin composition was produced in the same manner as in Example 1 except that the content ratio was changed as shown in Table 1. Table 1 shows the results of measuring the surface resistivity and the amount of particles generated for this injection-molded product.

[Example 11]
Instead of PEEK, epoxy resin [Mitsubishi Chemical Corporation, trade name “JER (registered trademark) YX4000HK”] 52 mass% and curing agent [Maywa Kasei Co., Ltd. epoxy resin curing agent DL-92 Synthetic resin in the same manner as in Example 1 except that the composition comprising 48% by mass was used, and the content ratio of each component in the synthetic resin composition was changed as shown in Table 1. An injection molded article formed by molding the composition was produced. Table 1 shows the results of measuring the surface resistivity and the amount of particles generated for this injection-molded product.

[Comparative Examples 1 and 2]
A synthetic resin composition was molded in the same manner as in Example 1 except that it did not contain a carbon precursor and the content ratio of each component in the synthetic resin composition was changed as shown in Table 2. An injection molded body was manufactured. Table 2 shows the results of measuring the surface resistivity and the amount of particles generated for this injection-molded product.

[Comparative Example 3]
A synthetic resin composition was molded in the same manner as in Example 4 except that it did not contain a carbon precursor and the content ratio of each component in the synthetic resin composition was changed as shown in Table 2. An injection molded body was manufactured. Table 2 shows the results of measuring the surface resistivity and the amount of particles generated for this injection-molded product.

[Comparative Example 4]
Instead of carbon nanotubes, carbon fiber [PAN-based carbon fiber: manufactured by Toho Tenax Co., Ltd., trade name “Tenax (registered trademark) HTA3000”, volume resistivity less than 10 ² Ω · cm, average fiber diameter 7.0 μm, average fiber The synthetic resin composition was molded in the same manner as in Example 1 except that the length of 80 μm] was used and the content ratio of each component in the synthetic resin composition was changed as shown in Table 2. An injection molded body was manufactured. Table 2 shows the results of measuring the surface resistivity and the amount of particles generated for this injection-molded product.

[Comparative Example 5]
Synthetic resin in the same manner as in Comparative Example 4, except that the PES was used instead of PEEK, and the content ratio of each component in the synthetic resin composition was changed as shown in Table 2. An injection molded article formed by molding the composition was produced. Table 2 shows the results of measuring the surface resistivity and the amount of particles generated for this injection-molded product.

[Comparative Example 6]
It is the same as that of the comparative example 4 except having replaced with PEEK and having used the mixture of this PEEK and said PES, and having changed the content rate of each component in a synthetic resin composition as shown in Table 2. Thus, an injection molded article formed by molding the synthetic resin composition was produced. Table 2 shows the results of measuring the surface resistivity and the amount of particles generated for this injection-molded product.

From Tables 1 and 2, the synthetic resin (A) 46 to 99.4% by mass, the volume resistivity 10 ² to 10 ¹⁰ Ω · cm of the carbon precursor (B) 0.5 to 40% by mass, and the volume resistance The synthetic resin compositions of Examples 1 to 11 containing 0.1 to 14% by mass of a conductive filler (C) that is a carbon nanotube and / or carbon nanofiber with a rate of less than 10 ² Ω · cm are formed. The molded body is
i) Since the surface resistivity of the compact is 4.6 × 10 ⁵ Ω / □ to 7.3 × 10 ¹¹ Ω / □ and is in the range of 10 ⁵ to 10 ¹² Ω / □, the electronic device It can be confirmed that it has semi-conductive electrical characteristics suitable for the transport tray or container of
ii) Since the ratio (Max / Min) between the maximum surface resistivity and the minimum surface resistivity is extremely small, 2 to 176, there is very little variation in the surface resistivity in the molded product, and the tray or container for transporting electronic devices. It can be seen that there is no risk of surface resistivity fluctuations, in some cases, semiconductive breakdown, etc.
iii) The generation amount of particles (particle size 0.5 μm or more) in pure water is as small as 260 to 1,460 particles / cm ^3, and the generation amount of particles having a particle size of 1.0 μm or more is particularly 32 to 165. pieces / cm ^3, generation of higher particle size 2.0μm particles is extremely small 4 to 31 / cm ^3, coarse since particles falling off is close almost no, the transport trays or containers of electronic devices When used in the above-mentioned applications, it was found that the material is resistant to contamination without causing contamination by dropped particles, fluctuation of surface resistivity, and in some cases, destruction of semiconductivity.

In addition, the synthetic resin compositions of Examples 1 to 11 in which the content of the carbon nanotubes or carbon nanofibers as the conductive filler (C) is as small as 0.5 to 5.0% by mass were molded. As a result that the molded body can be provided with the above-described excellent electrical properties and stain resistance, specifically, a synthetic resin (A) such as PEEK, PPS, PEI, PES, PC, or epoxy resin, Since it can be contained in a large amount of 77.5 to 98.0% by mass, the excellent mechanical and electrical properties of the synthetic resin (A) itself can be exhibited as desired, and the economy It turned out that it is excellent also in property.

On the other hand, Comparative Examples 1 to 3 which contain carbon nanotubes or carbon nanofibers as the conductive filler (C) but do not contain a carbon precursor (B) having a volume resistivity of 10 ² to 10 ¹⁰ Ω · cm. The molded product obtained by molding the synthetic resin composition has a ratio of maximum surface resistivity to minimum surface resistivity (Max / Min) as large as 1,600 to 120,000, and the surface resistivity of the molded product is high. It was found that due to the large variation, there was a risk of fluctuations in surface resistivity, and in some cases, semiconductive breakdown.

Further, the synthetic resins of Comparative Examples 4 to 6 which do not contain carbon nanotubes or carbon nanofibers as the conductive filler and contain a large amount of carbon fiber as the conductive filler at 22.0 to 24.5% by mass. molded body obtained by molding a synthetic resin composition containing the PEEK or PES as the particle generation amount is 2,932 pieces ^/ cm 3, 4,230 pieces / cm ³ or 10,000 / cm ³ greater than in Therefore, when used in applications such as electronic device transport trays or containers, it may cause contamination by dropped particles, fluctuations in surface resistivity, and in some cases, destruction of semiconductivity. I found out.

That is, synthetic resin (A) 46 to 99.4 mass%, volume resistivity 10 ² to 10 ¹⁰ Ω · cm of carbon precursor (B) 0.5 to 40 mass%, and volume resistivity 10 ² Ω · cm. The synthetic resin composition of the present invention containing 0.1 to 14% by mass of at least one conductive filler (C) selected from carbon nanotubes and carbon nanofibers of less than cm is the carbon precursor (B). And a synergistic effect of the combined use with at least one conductive filler (C) selected from carbon nanotubes and carbon nanofibers having a volume resistivity of less than 10 ² Ω · cm. When used for the above, there is no possibility of causing contamination by the dropped particles, fluctuation of the surface resistivity, and in some cases, destruction of the semiconductive property.

The reason why the synthetic resin composition of the present invention has a very small variation in surface resistivity in the molded body and a very small amount of particles generated is not necessarily clear, but can be presumed as follows. In other words, the carbon precursor of at least one conductive filler (C) and a volume resistivity of ¹⁰ 2 ^~ 10 10 Ω · cm selected from a predetermined amount of carbon nanotubes and carbon nanofibers having a volume resistivity of less than 10 ² Omega · cm By using together with (B), as compared with the carbon fiber that has been used as a conventional conductive filler, the equivalent semiconductivity can be realized with a very small amount of the conductive filler, resulting in dropout. It is considered that the amount of generated particles is reduced and the uniformity of the surface resistivity in the molded body is maintained.

According to the present invention, the synthetic resin (A) 46 to 99.4 mass%, the volume resistivity 10 ² to 10 ¹⁰ Ω · cm of the carbon precursor (B) 0.5 to 40 mass%, and the volume resistivity By being a synthetic resin composition containing 0.1 to 14% by mass of at least one conductive filler (C) selected from carbon nanotubes and carbon nanofibers of less than 10 ² Ω · cm, the surface resistivity is half Provided is a synthetic resin composition that is strictly controlled within a desired range of the conductive region, has a very small variation in surface resistivity, and generates a very small amount of foreign particles (particles). High availability.

Further, according to the present invention, the surface resistivity is strictly controlled within a desired range of the semiconductive region, and the surface resistivity is obtained by molding the synthetic resin composition. As a result, it is possible to obtain a molded product with extremely small variation in the generation amount of foreign particles (particles). Therefore, a transport tray or container for electronic devices having excellent characteristics, especially a transport tray for hard disk drive components. Alternatively, a container, among others, a magnetic head tray or a head gimbal assembly (HGA) tray can be provided, which has high industrial applicability.

Claims

Synthetic resin (A) 46-99.4% by mass, volume resistivity 10 2 to 10 10 Ω · cm of carbon precursor (B) 0.5-40% by mass, and volume resistivity less than 10 2 Ω · cm A synthetic resin composition containing 0.1 to 14% by mass of at least one conductive filler (C) selected from carbon nanotubes and carbon nanofibers.
The synthetic resin (A) is at least one selected from the group consisting of thermoplastic polyester, polyarylene sulfide, polyolefin, polycarbonate, polyether ether ketone, polyacetal, polyether imide, polyether sulfone, fluororesin, and epoxy resin. The synthetic resin composition according to claim 1.
A molded body formed by molding the synthetic resin composition according to claim 1 or 2.
The molded article according to claim 3, which is an injection molded article or an extruded molded article.
The molded product according to claim 3 or 4, wherein the amount of particles having a particle size of 0.5 µm or more measured in pure water is 2,000 particles / cm 3 or less.
The variation of the surface resistivity represented by the ratio (Max / Min) between the maximum surface resistivity (Max) and the minimum surface resistivity (Min) is 1,000 or less. The molded body described.
The molded body according to any one of claims 3 to 6, which is a tray or a container for transporting an electronic device.
The molded body according to claim 7, which is a tray or container for transporting hard disk drive components.
The molded article according to claim 8, which is a magnetic head tray or a head gimbal assembly (HGA) tray.