JP2009127038A - Resin composition, method for producing the same and use of the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a resin composition etc., having a good reproducibility of volume resistivity, and having less change in electroconductivity even though the molding conditions of various molding methods are changed. <P>SOLUTION: This resin composition is provided by blending carbon fibers having a 5 to 500 nm mean fiber diameter, a non-electroconductive fibers having a mean fiber diameter of 500 nm or less and a resin, wherein the blending ratio of the carbon fibers X is 1 to 20 mass% and the blending ratio Y of the non-electroconductive fibers satisfies the relation ship: X<Y. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a resin composition, a production method thereof, and an application thereof.

A resin having a volume resistivity of 10 ⁶ to 10 ¹² Ωcm has a volume resistivity intermediate between that of a metal and an insulator, and thus is generally called a semiconductive resin. The semiconductive resin makes use of functions such as antistatic properties and dust adsorption preventive properties, for example, a charging roll in an image forming apparatus such as an electrophotographic copying machine or an electrostatic recording apparatus, It is used as a charging belt, a static elimination belt; a resin material for a charging member such as a container for transporting semiconductor components. However, in recent years, in order to increase the transfer efficiency of a copying machine, to obtain a clearer image, or to neutralize static electricity charged on a precision part gently, even in the semiconductive region, such as 10 ¹⁰ to 10 ¹² Ωcm. It is required to control the resistance within a very narrow range.

  Usually, in order to impart conductivity to a resin that is electrically insulating, (1) a surfactant is added, (2) an alloy with a hydrophilic polymer containing a conductive unit in the molecule, (3) There is a method of mixing conductive materials such as metals and carbon materials.

(1) In the method using a surfactant, the low molecular weight surfactant bleeds out to the resin surface and adsorbs moisture in the atmosphere to develop conductivity. However, the volume resistivity obtained at this time is about 10 ⁹ to 10 ¹² Ωcm, and when the surface is further washed, the bleed-out surfactant is washed away and the conductivity is lowered. .

(2) Regarding alloying with a hydrophilic polymer, since the movement of ions dominates electrical conduction, the volume resistivity obtained is limited to 10 ⁹ to 10 ¹² Ωcm. Moreover, in the polymer alloy, since the size and shape of the dispersed phase easily change depending on the molding conditions, it is difficult to stably form the ion conduction path. As a result, there is a problem that the resistance cannot be precisely controlled.

(3) Regarding the method of mixing conductive materials, when conductive materials are added to the resin, a three-dimensional conductive network is formed with a certain addition amount, and the resistance is increased from 10 ¹⁶ to 10 ⁰ Ωcm. A rapidly decreasing percolation phenomenon is observed. Therefore, it is generally difficult to control the resistance in the range of 10 ⁶ to 10 ¹² Ωcm. Under such circumstances, a resin composition is proposed in which a matrix thermoplastic resin, fine carbon fibers having an average diameter of 200 nm or less, and a thermoplastic resin and / or a thermoplastic elastomer other than the matrix are arranged (for example, patents). Reference 1).

  There has also been proposed a resin composition obtained by combining carbon fiber and a polymer type antistatic agent in a matrix resin, which is a combination of the above methods (2) and (3) (see, for example, Patent Document 2). )

Furthermore, the conductive thermoplastic resin (A) containing carbon black and / or carbon fiber and having a surface resistance value of 10 ⁶ Ω or less, and carbon black and / or carbon fiber compatible with (A) are contained. There has been proposed a resin composition obtained by mixing a conductive thermoplastic resin (B) having a surface resistance value of 10 ¹² Ω or more (see, for example, Patent Document 3).

  On the other hand, resin compositions containing carbon precursor particles and carbon fibers in a synthetic resin have been proposed (see, for example, Patent Documents 4 to 6).

JP 2003-261688 A JP 2003-313428 A JP 2001-247772 A JP 2002-121402 A JP 2002-80720 A JP-A-9-87418

The method described in Patent Document 1 forms an island structure of a dispersed phase resin in the matrix resin (sea) by using an incompatible resin, and the contact between the fine carbon fibers is divided by the dispersed phase resin, It is to obtain semiconductivity. In this method, as in the alloying with the hydrophilic polymer, it is difficult to control the size and shape of the dispersed phase depending on the molding conditions, so that the semiconductivity cannot be stably obtained.
Similarly, in the method described in Patent Document 2, it is difficult to stably control the sea-island structure depending on molding conditions, so that it is difficult to obtain semiconductivity.

The method described in Patent Document 3 simply mixes two types of conductive resins, but the dispersion / distribution state of the two types of resins greatly changes depending on the kneading strength when mixing, particularly when kneading unevenness occurs. Will result in a wide resistance of 10 ⁶ to 10 ¹² Ω.

  In the methods described in Patent Documents 4 to 6, a desired resistance cannot be obtained unless the total amount of the carbon precursor particles and the carbon fibers is 30% by mass or more, and the conductivity is adjusted by a shearing force during kneading or molding. There is a problem that the rigid carbon fiber used as a material breaks and the resistance value fluctuates greatly.

  As described above, the present invention provides a resin composition with good reproducibility of volume resistivity and small change in conductivity even when the molding conditions of various molding methods are changed, its production method, and its application. With the goal.

  As a result of intensive studies to solve the above problems, the present inventor has arrived at the following present invention and found that the problems can be solved. That is, the present invention is as follows.

(1) Carbon fibers having an average fiber diameter of 5 to 500 nm, non-conductive fibers having an average fiber diameter of 500 nm or more, and a resin are blended, and the blending ratio X of the carbon fibers is 1 to 20% by mass,
A resin composition in which a blending ratio Y of the nonconductive fibers satisfies a relationship of X <Y.
(2) The resin composition according to (1), wherein the volume resistivity is in the range of 1 × 10 ⁰ to 1 × 10 ¹² Ωcm.
(3) The resin composition according to (1) or (2), wherein the carbon fiber before blending has an average fiber diameter of 5 to 500 nm, an aspect ratio of 40 or more, and a volume resistivity of 10 ⁻² Ωcm or less.
(4) The resin composition according to any one of (1) to (3), wherein the nonconductive fibers before blending are inorganic fibers or organic fibers having an average fiber diameter of 500 nm or more.

(5) The resin before blending is polyethylene, polypropylene, polystyrene, ABS resin, polyacetal, aliphatic polyamide, aromatic polyamide, polyethylene terephthalate, polybutylene terephthalate, polycarbonate, modified polyphenylene ether, polyphenylene sulfide, cycloolefin polymer, liquid crystal (1) to (1) which is at least one kind of thermoplastic resin such as polymer, polyetherimide, polysulfone, polyethersulfone, polyamideimide, thermoplastic polyimide, polyetherketone, polyetheretherketone, fluororesin, and polybenzimidazole. The resin composition according to any one of 4).
(6) The resin before compounding is at least one thermosetting resin selected from epoxy resin, polyurethane, phenol resin, diallyl phthalate resin, unsaturated polyester resin, urea resin, melamine resin, silicone resin, polyimide resin, and allyl ester resin. The resin composition according to any one of (1) to (4), which is a resin.

(7) including a melt-kneading step of introducing and melting and kneading carbon fibers having an average fiber diameter of 5 to 500 nm and non-conductive fibers having an average fiber diameter of 500 nm or more into the resin;
A method for producing a resin composition, wherein the carbon fiber and the non-conductive fiber are introduced into a molten resin made of the resin when the melt kneading.
(8) including a melt-kneading step of introducing and melting and kneading carbon fibers having an average fiber diameter of 5 to 500 nm and non-conductive fibers having an average fiber diameter of 500 nm or more into the resin, The resin is a polymer particle having a volume average particle size of 200 μm or less, and the melt kneading is performed by dry-mixing the polymer particle and the carbon fiber and performing melt kneading, and then the non-conductive fiber is placed in the molten resin. The manufacturing method of the resin composition introduce | transduced into this.

(9) The resin composition according to any one of (1) to (6) is molded, and the variation in volume resistivity at each of four randomly selected positions is 10 ^{X ± 1} Ωcm ( A molded body satisfying 0 ≦ X ≦ 12).
(10) The molded body according to (9), wherein the molded body is an injection molded body, a compression molded body, or an extrusion molded body.
(11) Even if the injection speed is changed, carbon fiber and non-conductivity can be produced, which can produce an injection-molded body in which the volume resistivity change of the injection-molded body is in the range of 10 ^{X ± 2} Ωcm (0 ≦ X ≦ 12). Resin composition in which a functional fiber and a resin are blended.
(12) Even if the cooling conditions change, non-conductive carbon fibers and compression molded bodies that can produce compression molded bodies whose volume resistivity changes within the range of 10 ^{X ± 2} Ωcm (0 ≦ X ≦ 12) Resin composition in which a functional fiber and a resin are blended.
(13) Even if the extrusion speed changes, carbon fibers and non-conductive materials can be produced which can produce an extruded product having a volume resistivity change of 10 ^{X ± 2} Ωcm (0 ≦ X ≦ 12). Resin composition in which a functional fiber and a resin are blended.
(14) A molded article molded using the resin composition according to any one of (11) to (13).

(15) A conveying part formed by using the resin composition according to any one of (1) to (6) and (11) to (13).
(16) The transport component according to (15), which is used in a clean room.
(17) A heat-resistant sliding member formed by using the resin composition according to any one of (1) to (6) and (11) to (13).
(18) The compression molded body or extruded molded body according to any one of (10), (13), and (14) is cut and applied to any of bearings, gears, and manufacturing machine parts. Heat-resistant sliding member that can be used.
(19) Various rolls used in IC test sockets, spin chucks, copiers, seamless belts, antistatic fibers, using the resin composition according to any one of (1) to (18) and various molded articles. Electrostatic coating member, fuel tube, fuel peripheral member, chemical tube, IC tray, or carrier tape.

  ADVANTAGE OF THE INVENTION According to this invention, the reproducibility of a volume resistivity is favorable, and even if the molding conditions of various shaping | molding methods change, a resin composition with little change of electroconductivity, its manufacturing method, and its use can be provided. it can.

[1. Resin composition]
The resin composition of the present invention comprises carbon fiber, nonconductive fiber, and resin. Hereinafter, each component will be described.

(Carbon fiber)
The carbon fiber according to the present invention has an average fiber diameter of 5 to 500 nm. When the average fiber diameter is less than 5 nm, the surface energy increases exponentially, and the cohesive force between the fibers increases rapidly. When such fine graphitized fibers are simply kneaded with resin, they cannot be sufficiently dispersed, and aggregates are scattered in the resin, making it impossible to efficiently form a conductive network. The reproducibility of will not be obtained. In addition, the uniformity and stability of the resistance are reduced.

  On the other hand, if the average fiber diameter exceeds 500 nm, it is necessary to mix more carbon fibers in order to obtain the desired conductivity, and the stabilization of conductivity will be significantly reduced. The average fiber diameter is preferably 30 to 200 nm.

  In addition, an average fiber diameter can be calculated | required as follows, for example. That is, first, the carbon fiber is observed with a scanning electron microscope at a magnification of 100 to 30,000 times. The observed photograph is taken into an image analysis apparatus (LUZEX-AP manufactured by Nireco), the fiber diameter of 300 carbon fibers is measured, and the number average fiber diameter is obtained.

  Moreover, the compounding ratio X of the carbon fiber is 1 to 20% by mass. When the blending ratio is less than 1% by mass, desired conductivity is not exhibited. When it exceeds 20 mass%, the fluidity at the time of shaping | molding will fall. The blending ratio is preferably 2 to 18% by mass.

The aspect ratio of the carbon fiber used in the present invention is preferably 40 or more, more preferably 60 to 500, and further preferably 80 to 300. By setting the aspect ratio to 40 or more, the amount of carbon fiber added can be reduced. The carbon fiber volume resistivity is preferably 10 ⁻² Ωcm or less. By being 10 ⁻² Ωcm or less, a highly conductive composition can be produced.

  The aspect ratio can be obtained by the average fiber length / average fiber diameter. The average fiber length can be determined, for example, as follows. That is, first, the carbon fibers are continuously observed in a panoramic shape with a 100 to 3000 magnification image of a scanning electron microscope. The observed photograph is taken into an image analyzer, the fiber length of 300 carbon fibers is measured, and the number average fiber length can be obtained.

  Preferable materials for such carbon fibers include fine graphitized fibers and carbon nanotubes. Considering the difficulty of forming secondary aggregates and higher-order aggregates in which secondary aggregates gather together, fine graphitized fibers are preferred.

Fine graphitized fibers form aggregated particles due to weak electrostatic force, which can be easily unraveled by the shearing force during kneading, and are dispersed uniformly and reproducibly one by one in the resin. Has the advantage that it can. Therefore, it can be said that it is a good conductive filler that controls the resistance in the semiconductive region.
Carbon nanotubes are also an effective material when the dispersion of aggregates during kneading, that is, when the aggregate particle size can be precisely controlled.
The form of fine graphitized fiber is described below.

  First, the average fiber diameter of the fine graphite fiber is set to 5 to 500 nm as described above. In the case of fine graphite fibers, the reason why the thickness is particularly 500 nm or less lies in the growth mechanism of fine carbonaceous fibers (products immediately after reaction and before graphitization) in the chemical vapor deposition method. In general, when pyrolyzed carbon dissolves and precipitates in catalyst fine particles of several nanometers, the fiber grows in the length direction as the first stage (growth of hollow tube). This lengthwise growth is said to end at the very beginning of the reaction. Subsequently, the pyrolyzed carbon is deposited and deposited on the outer wall of the hollow tube, so that the radial direction of the fiber grows. That is, in this chemical vapor deposition method, the length of the fiber is almost determined at the beginning of the reaction, and the diameter is determined by the reaction time. Therefore, as the fiber diameter increases, the aspect ratio of the fine carbonaceous fibers naturally decreases.

From the viewpoint of improving conductivity, the average spacing d ₀₀₂ by X-ray diffraction of the fine graphitic fibers is preferably, d ₀₀₂ 0.337~0.341nm be d ₀₀₂ 0.336~0.343nm It is more preferable that d _{002 is} 0.338 to 0.340 nm.

On the other hand, when the average interplanar spacing d ₀₀₂ exceeds 0.3453 nm, the crystal is not sufficiently developed, so the resistivity of the single fiber is 10 times or more larger than that of the crystallized fine graphite fiber. Therefore, when mixed with a resin, movement of electrons between fine carbonaceous fiber / resin / fine carbonaceous fiber becomes difficult, and stabilization of conductivity may be reduced.

  The production method of the fine graphite fiber is not particularly limited, and a known production method can be applied. For example, it can be produced by pyrolyzing a carbon source (hydrocarbon compound or the like) in the presence of a metal catalyst. it can.

  The carbon source used as the raw material for the fine graphitic fiber may be a gas such as toluene, benzene, naphthalene, ethylene, acetylene, ethane, natural gas, carbon monoxide, or a mixture thereof. Of these, aromatic hydrocarbons such as toluene and benzene are preferred. As the metal catalyst, one or more selected from the elements of Periodic Tables 4 to 10 can be adopted. An organometallic compound can also be employed as the metal catalyst, and preferred organometallic compounds include ferrocene and nickelocene.

  A sulfur compound such as sulfur or thiophene can be used as a co-catalyst in order to efficiently remove a gas such as hydrogen adsorbed on the surface of the metal catalyst particles and enhance the catalytic activity in a pyrolysis reaction atmosphere.

  It is also possible to use a reducing gas such as hydrogen as a carrier gas, supply the carbon source and the metal catalyst to a reaction furnace heated to 500 to 1300 ° C., and cause thermal decomposition reaction to obtain fine graphite fibers, It is also possible to obtain fine graphite fibers by supporting a metal catalyst on a carrier and supplying a carbon source.

  As a form of the raw material, a material obtained by dissolving an organic transition metal compound and a sulfur compound in an aromatic hydrocarbon, or a material vaporized at 500 ° C. or lower can be used. However, in the case of a liquid raw material, vaporization / decomposition of the raw material occurs on the reaction tube wall, and the concentration distribution of the raw material locally occurs in the reaction tube, so that the produced vapor grown carbon fibers tend to aggregate. Therefore, as a form of the raw material, a vaporized raw material having a constant raw material concentration in the reaction tube is preferable.

  When a sulfur compound is used as a promoter, the metal catalyst to sulfur compound promoter ratio (sulfur / (metal + sulfur)) is preferably 10 to 35% by mass. In the case of 10% by mass or more, hydrogen adsorbed on the catalyst can be sufficiently removed, and it is possible to prevent the supply of the carbon source to the catalyst and the generation of carbon particles other than the fibers. In addition, when the amount is 35% by mass or less, the catalyst activity is prevented from being excessively increased, the fiber branching is increased, the fibers are radially formed, and the interaction between the fibers is prevented from increasing. The formation of aggregated particles can be prevented.

  The ratio of the raw material supply amount in the reaction tube to the carrier gas flow rate is preferably 1 g / liter or less, more preferably 0.5 g / liter, and even more preferably 0.2 g / liter. When the raw material concentration in the gas phase is 1 g / liter or less, non-uniform nuclei of catalyst particles are generated on the generated vapor grown carbon fiber surface, or fine carbonaceous fibers are further generated from the fine carbonaceous fiber surface. Further, the formation of frost-like fine carbonaceous fibers is prevented, and the dispersibility can be improved.

  In order to remove organic substances such as tar adhering to the surface of the fine graphite fiber produced by the reaction, it is preferable to perform heat treatment at 900 to 1300 ° C. in an inert atmosphere. In order to improve the electrical conductivity of the fine graphite fiber, it is possible to further perform a heat treatment at 2000 to 3500 ° C. under an inert atmosphere to develop crystals, but when there is almost no disturbance of the graphite layer, It is also possible to employ fibers that have been produced without heat treatment.

  The heat treatment furnace used for crystal growth may be any furnace that can be maintained at a desired temperature of 2000 ° C. or higher, preferably 2300 ° C. or higher, and any ordinary apparatus such as an Atchison furnace, a resistance furnace, a high-frequency furnace, or the like. But you can. In some cases, a method of directly energizing and heating the powder or molded body can also be used.

  The atmosphere for the heat treatment is a non-oxidizing atmosphere, preferably an atmosphere of one or more rare gases such as argon, helium, neon and the like. The heat treatment time is preferably as short as possible from the viewpoint of productivity. If heating is continued for a long time, the product yield deteriorates because it sinters and hardens. Therefore, after the temperature of the center part of the molded body or the like reaches the target temperature, it is sufficient to hold the temperature for 10 minutes to 1 hour.

In order to further develop crystals of fine graphite fibers and improve conductivity, boron carbide (B ₄ C), boron oxide (in the graphitization treatment heated at 2000 to 3500 ° C. in an inert atmosphere ( B ₂ O ₃ ), elemental boron, boric acid (H ₃ BO ₃ ), borate and other boron compounds may be mixed.

The amount of boron compound added depends on the chemical and physical properties of the boron compound used, and cannot be specified unconditionally. For example, when boron carbide (B ₄ C) is used, The range is 0.05 to 10% by mass, preferably 0.1 to 5% by mass.

  By heat treatment with the boron compound, the crystallinity of graphite in the fine graphite fiber is improved, and the conductivity is further improved. The amount of boron contained in the crystal of the fine graphite fiber or in the crystal surface is preferably 0.01 to 5% by mass. In order to improve the electrical conductivity of the fine graphite fiber and the affinity with the resin, more preferably 0.1% by mass or more of boron is required. Further, the amount of boron that can be substituted into the graphene sheet is about 3% by mass, and more than that, especially 5% by mass or more of boron exists as boron carbide or boron oxide, which is not preferable because it may cause a decrease in conductivity.

  In order to improve the affinity between the fine graphite fiber and the resin, the fine graphite fiber can be oxidized to introduce a phenolic hydroxyl group, a carboxyl group, a quinone group, or a lactone group on the surface. Furthermore, surface treatment may be performed with a silane-based, titanate-based, aluminum-based, or phosphate ester-based coupling agent.

(Non-conductive fiber)
The non-conductive fiber according to the present invention has an average fiber diameter of 500 nm or more. If the average fiber diameter is less than 500 nm, the fine dispersibility of the non-conductive fibers becomes high, and the conductive network of carbon fibers is destroyed. The average fiber diameter is preferably 1 μm or more. The average fiber diameter can be obtained by the method described above.

  It is essential that the blending ratio Y of the nonconductive fibers satisfies the relationship of X <Y, and it is more preferable to make the difference between X and Y as large as possible. By satisfying the relationship of X <Y, it is considered that a network of nonconductive fibers is formed and carbon fibers are easily dispersed therein. As a result, even when various molded products are molded, good reproducibility of the desired volume resistivity can be obtained. The difference between Y and X (Y-X) is preferably 5% by mass or more, and more preferably 10% by mass or more.

Non-conductive fibers are preferably inorganic fibers or organic fibers, and examples thereof include glass fibers, whiskers, inorganic fibers, ore fibers, and the like. Examples of the whisker include silicon nitride whisker, silicon trinitride whisker, basic magnesium sulfate whisker, barium titanate whisker, silicon carbide whisker, and boron whisker. Examples of the inorganic fiber include various fibers such as rock wool, zirconia, alumina silica, potassium titanate, barium titanate, titanium oxide, silicon carbide, alumina, silica, and blast furnace slag. Examples of the ore fiber include asbestos. Among these, glass fiber and potassium titanate are preferable.
Examples of organic fibers include synthetic resin fibers such as aramid fibers, acrylic fibers, and polyester fibers; semi-synthetic fibers such as cellulose fibers; natural fibers;

(resin)
As the resin, a thermoplastic resin and / or a thermosetting resin can be used.
Thermoplastic resins include polyethylene, polypropylene, polystyrene, cycloolefin polymers; Nylon 11, Nylon 12, Nylon 6, Nylon 610, Nylon 612, Nylon 66 and other aliphatic polyamides and aromatic polyamides; AS resin (acrylonitrile / styrene co-polymer) Polymer), ABS resin (acrylonitrile / styrene / butadiene copolymer), polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate; liquid crystal polymer such as liquid crystal polyester; polyphenylene sulfide, polycarbonate, polysulfone, polyethersulfone, polyimide (in particular, Thermoplastic polyimide), polyether imide, polyamide imide, polyether ketone, polyether ether ketone, poly Tar, polyphenylene ether, modified polyphenylene ether, can be selected from the group consisting of polybenzimidazole, a fluororesin.

  Among them, polyethylene, polypropylene, polystyrene, ABS resin, polyacetal, aliphatic polyamide, aromatic polyamide, polyethylene terephthalate, polybutylene terephthalate, polycarbonate, modified polyphenylene ether, polyphenylene sulfide, cycloolefin polymer, liquid crystal polymer, polyetherimide, polysulfone , Polyethersulfone, polyamideimide, thermoplastic polyimide, polyetherketone, polyetheretherketone, fluororesin, and polybenzimidazole are preferred.

  From the viewpoint of heat resistance and chemical resistance, polyether ether ketone, polyether sulfone, polyether imide, and liquid crystal polymer are preferable. From the viewpoint of mechanical strength, polycarbonate, polyphenylene ether, and polybutylene terephthalate are preferable. From the viewpoint of low water absorption and low outgas, it can be said that a cycloolefin polymer is preferable.

  As the thermosetting resin, for example, a thermosetting resin such as epoxy resin, polyurethane, phenol resin, diallyl phthalate resin, unsaturated polyester resin, urea resin, melamine resin, silicone resin, polyimide resin, allyl ester resin is blended. Also good. In this case, it is preferable that the thermosetting resin is blended in the same manner as the above-described thermoplastic resin.

[2. Method for producing resin composition]
The method for producing the resin composition of the present invention is a melt-mixing method in which carbon fibers having an average fiber diameter of 5 to 500 nm and non-conductive fibers having an average fiber diameter of 500 nm or more are introduced into the resin described above and melt-kneaded. Includes smelting process.

  The details of carbon fiber, non-conductive fiber, resin, etc. are as described above. The melt kneading mode is any one of the following modes.

  A 1st aspect is an aspect which introduce | transduces a carbon fiber and a nonelectroconductive fiber in the molten resin which consists of resin, when melt-kneading. The order of introduction of carbon fibers and non-conductive fibers, the introduction interval, etc. are not particularly limited.

  The second embodiment uses polymer particles having a volume average particle size of 200 μm or less as a resin before melt kneading, dry-mixes the polymer particles and carbon fibers, and performs melt kneading, In this embodiment, the conductive fiber is introduced into the molten resin.

  By using polymer particles having a volume average particle size of 200 μm or less, breakage due to the shearing force between the solid polymer mass and the carbon fiber can be suppressed. In addition, the process as described above can suppress fiber breakage and improve fiber dispersion.

Preferred conditions common to the first aspect and the second aspect will be described below.
First, when kneading the carbon fiber and the non-conductive fiber with the resin, particularly when fine graphite fiber is used as the carbon fiber, it is preferable to suppress breakage of the fine graphite fiber as much as possible. Specifically, the breakage rate of the fine graphite fiber is preferably suppressed to 20% or less, more preferably 15% or less, and particularly preferably 10% or less. In order to perform kneading while minimizing breakage of the fine graphite fiber, for example, the following method can be used.

  In general, when an inorganic filler is melt-kneaded with a resin, a high shearing force is applied to the aggregated inorganic filler, the inorganic filler is broken and refined, and the inorganic filler is uniformly dispersed in the molten resin. As a kneading machine that generates a high shearing force, a machine that uses a stone mortar mechanism or a machine that introduces a kneading disk that applies a high shearing force into a screw element using a twin screw extruder is used. However, if such a kneader is used, the fine graphitic fibers are broken during the kneading step. Further, in the case of a single screw extruder having a weak shearing force, fiber breakage can be suppressed, but fiber dispersion is not uniform. Therefore, in order to achieve uniform dispersion while suppressing fiber breakage, the shear force can be reduced with a co-directional twin-screw extruder that does not use a kneading disk, or a high shear force such as a pressure kneader can be applied. However, it is desirable to use a special mixing element that can achieve dispersion over time or a single screw extruder.

  Further, as a method for introducing fine graphitic fibers into a kneader, a method for introducing it into a molten resin is preferable. For example, when fine graphite fiber and resin are kneaded with a same-direction twin screw extruder, resin pellets are put into a hopper upstream of the kneader. A method is preferred in which resin pellets are melted by heating with a heater and shearing heat generation of a screw, and fine graphite fibers are side-fed into the melted resin from the middle of the kneader and kneaded. If the fine graphite fiber and the resin pellet are simultaneously fed into the extruder from the hopper, the fine graphite fiber is pulverized by the pellet before the pellet is melted, which is not preferable.

The fine graphitic fiber used in the present invention has a bulk specific gravity of about 0.01 to 0.1 g / cm ³ and is easy to entrain air, so that it is difficult to deaerate with a normal single screw extruder or a co-directional twin screw extruder. It is difficult to fill the resin. In such a case, a batch-type pressure kneader can be used as a kneader that has good filling properties and minimizes fiber breakage. What knead | mixed with the batch-type pressure kneader can also be thrown into a single-screw extruder before solidification, and can also be pelletized.

The resin composition of the present invention produced as described above preferably has a volume resistivity of 1 × 10 ⁰ to 1 × 10 ¹² Ωcm. And when the said resin composition is set as a various molded object, it is possible to control volume resistivity to a desired value within a semiconductive area | region (10 < ⁶ > -10 < ¹² > (omega | ohm) cm), and volume resistivity Reproducibility can be improved.
In addition, according to such a resin composition, even if the injection speed is changed, the injection molded body in which the change in the volume specific resistance of the injection molded body is in the range of 10 ^{X ± 2} Ωcm (0 ≦ X ≦ 12); Even if the cooling conditions are changed, the compression molded body has a volume resistivity change of 10 ^{X ± 2} Ωcm (0 ≦ X ≦ 12) within the range of the compression molded body; It is possible to produce an extruded product having a change in volume resistivity of 10 ^{X ± 2} Ωcm (0 ≦ X ≦ 12).
Here, “even if the injection speed changes” means that, for example, even if the injection speed in the mold changes from 20 to 100 mm / sec as a linear velocity, more preferably changes from 10 to 500 mm / sec. However, it means that the change in volume resistivity falls within the range of 10 ^{X ± 2} Ωcm (0 ≦ X ≦ 12).
“Even if the cooling conditions change” means, for example, whether the cooling is natural cooling or a cooling press, specifically, the cooling rate changes from 500 ° C./sec to 50 ° C./min. However, it means that the change in volume resistivity falls within the range of 10 ^{X ± 2} Ωcm (0 ≦ X ≦ 12).
“Even if the extrusion speed changes”, for example, even if the extrusion speed changes from 1 m / h to 50 m / h, the change in volume resistivity is in the range of 10 ^{X ± 2} Ωcm (0 ≦ X ≦ 12). It means being inside.

[3. Molded body]
The molded body of the present invention is formed by using the resin composition of the present invention. The variation of the volume resistivity at each of the four randomly selected positions is 10 ^{X ± 1} Ωcm (0 ≦ X ≦ 12). When the variation is 10 ^{X ± 1} Ωcm, there is no potential variation due to electrification in the molded body (when there is variation, sparking is likely), and an overcurrent path is unlikely to occur. Therefore, a semiconductor chip etc. can be preserve | saved.

Examples of the form of the molded body of the present invention include an injection molded body, a compression molded body, an extrusion molded body, a sheet molded body, a film molded body, a cast molded body, and a fibrous molded body, depending on the molding method. In view of more effective use of the characteristics of the present invention, an injection-molded body, a compression-molded body, and an extrusion-molded body are preferable. In any of these cases, it is preferable that the variation of the volume resistivity at each of the four randomly selected positions is 10 ^{X ± 2} Ωcm (0 ≦ X ≦ 12) as described above. In addition, when the characteristics of the present invention are used effectively, there is little variation in conductivity even when the molding conditions change at the manufacturing site.

In the molded body of the present invention, when a molded body having a surface area of 100 cm ² is immersed in 500 ml of pure water and an ultrasonic wave of 40 kHz is applied for 60 seconds at a temperature of 23 ° C., the particle diameter is 1 μm. The number of the above particles can be suppressed to 5,000 pcs / cm ² or less per unit surface area of the molded body.

By suppressing the number of particles having a particle diameter of 1 μm or more to drop off to 5,000 cps / cm ² or less, good sliding resistance and conductivity stabilization can be achieved. Further, in the molded body of the present invention, the content of carbon fiber is extremely small, and therefore, in the tensile test of a molded product having only the same shape and a matrix resin, the tensile elongation retention rate of the molded body is It can be made 50% or more with respect to the tensile elongation of the molded product made of only the matrix resin. Further, in a film molded body or sheet molded body formed by molding a molten resin composition, the decrease in volume resistivity of the 4-fold stretched product is 1 × 10 ⁴ Ω · cm or less with respect to the molded body before stretching. be able to.

[4. Method for producing molded body]
In the manufacturing method of the molded object of this invention, the process (molded object preparation process) of producing a molded object using the resin composition of this invention is included. In this step, it is preferable to lower the viscosity of the molten resin by setting the upper molding temperature at which the resin does not deteriorate.

  As the molding method, a conventionally known method such as an injection molding method, a compression molding method, an extrusion molding method, a sheet molding method, a spinning method, a cast film molding method and the like can be used.

  In particular, as an injection molding method, in addition to a general injection molding method, metal parts by insert injection molding method, integral molding with other parts, two-color injection molding method, core back injection molding method, sandwich injection molding Various molding methods such as a method and an injection press molding method can be used. In injection molding, since the surface resistance value of a product varies depending on the resin temperature, mold temperature, and molding pressure, it is necessary to set appropriate conditions.

[5. Use of the resin composition of the present invention]
Specific uses of the conductive resin composition of the present invention (application examples of the molded product of the present invention) include, in the electric and electronic field, wafer carriers, wafer cassettes, tote bins, wafer boats, IC trays (for example, IC chip trays). ), IC chip carrier, IC transport tube, IC card, tape (for example, carrier tape) and reel packing, liquid crystal cassette, various cases, storage tray, storage bin, transport device parts, magnetic card reader, connector, computer slot HD carrier, MR head carrier, GMR head carrier, HSA carrier, HDD VCM, liquid crystal panel carrier, and the like.

  In the OA equipment field, charging members such as charging rolls, charging belts, static elimination belts, transfer rolls, transfer belts, and developing rolls in image forming apparatuses such as electrophotographic copying machines and electrostatic recording apparatuses; transfer drums for recording apparatuses, and printed circuits Substrate cassette, bush, paper and banknote transport parts, paper feed rail, font cartridge, ink ribbon canister, guide pin, tray, roller, gear, sprocket, computer housing, modem housing, monitor housing, CD-ROM housing, printer housing , Connectors, computer slots, etc.

In the field of communication equipment, mobile phone parts, pagers, various sliding materials and the like can be mentioned.
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 can be mentioned. In other fields, electric wires and power cable covering materials, electric wire supports, radio wave absorbers, flooring materials, carpets, insect repellent sheets, pallets, shoe soles, tapes, brushes, blower fans, planar heating elements, polyswitches, etc. It is done.

  Hereinafter, the present invention will be specifically described by way of examples, but the present invention is not limited thereto. First, the raw materials and samples used in the examples will be described.

[Fine graphitic fiber]
The following samples 1 to 5 were used as fine graphite fibers which are carbon fibers.
Sample 1 Carbon nanofiber manufactured by Showa Denko KK Product name: VGCF-S, average fiber diameter 100 nm
Sample 2 Carbon nanofiber manufactured by Showa Denko KK Product name: VGNF, average fiber diameter 80 nm
Sample 3 Carbon nanofiber manufactured by Showa Denko KK Product name: VGCF, average fiber diameter 150 nm
Sample 4 Average fiber diameter 40 nm Vapor grown carbon fiber Sample 5 Average fiber diameter 10 nm Vapor grown carbon fiber

(Production of Sample 1 VGCF-S)
In this example, a commercially available product such as VGCF-S is used, but this can be produced, for example, as follows.
First, benzene, ferrocene, and thiophene were mixed at a mass ratio of 92: 7: 1 to prepare a raw material solution. This raw material liquid was supplied to an evaporator set at 400 ° C. and vaporized. The vaporized source gas was supplied together with carrier hydrogen gas to a SiC reactor (inner diameter 120 mm, height 2000 mm) heated to 1250 ° C. The raw material supply amount at this time was 10 g / min, and the hydrogen flow rate was 60 liters / min.

  80 g of the obtained reaction product was filled in a graphite crucible (inner diameter 100 mm, height 150 mm) and baked at 1000 ° C. for 1 hour in an argon atmosphere. A graphite crucible (inner diameter: 100 mm, height: 150 mm) was filled with 80 g of fine carbonaceous fibers fired at 1000 ° C., and graphitized at 3000 ° C. for 30 minutes in an argon atmosphere using a high-frequency heating furnace. Produced.

(Production of vapor grown carbon fiber of sample 4)
First, benzene, ferrocene, and thiophene were mixed at a weight ratio of 92: 7: 1 to prepare a raw material solution. This raw material liquid was supplied to an evaporator set at 400 ° C. and vaporized. The vaporized source gas was supplied together with carrier hydrogen gas to a SiC reactor (inner diameter 120 mm, height 2000 mm) heated to 1250 ° C. The raw material supply amount at this time was 8 g, and the hydrogen flow rate was 80 liters / min.

  80 g of the obtained reaction product was filled in a graphite crucible (inner diameter: 100 mm, height: 150 mm), fired at 1000 ° C. for 1 hour in an argon atmosphere, then graphitized at 2800 ° C. for 30 minutes in an argon atmosphere. A phase-processed carbon fiber was prepared.

(Production of vapor grown carbon fiber of sample 5)
First, benzene, ferrocene, and thiophene were mixed at a weight ratio of 92: 7: 1 to prepare a raw material solution. This raw material liquid was supplied to an evaporator set at 400 ° C. and vaporized. The vaporized source gas was supplied together with carrier hydrogen gas to a SiC reactor (inner diameter 120 mm, height 2000 mm) heated to 1250 ° C. The raw material supply amount at this time was 5 g, and the hydrogen flow rate was 60 liters / min.

  80 g of the obtained reaction product was filled in a graphite crucible (inner diameter: 100 mm, height: 150 mm), baked at 1000 ° C. for 1 hour in an argon atmosphere, then graphitized at 2800 ° C. for 30 minutes in an argon atmosphere. A phase-processed carbon fiber was prepared.

(Carbon fiber with an average fiber diameter exceeding 500 nm)
Moreover, carbon fiber chopped strands (average fiber diameter: 7000 nm or less, also referred to as “CF”) manufactured by Toho Tenax Co., Ltd. were used as carbon fibers having an average fiber diameter exceeding 500 nm.

[Non-conductive fibers, etc.]
As non-conductive fibers, GFPC11, GFPC13, GFPPE11, GFPEEK11, GFPET11, and Tismo D were used. Moreover, mica powder was used as non-conductive particles. These details are as follows.

GFPC11 Nittobo's chopped strand glass fiber for PC
Average fiber diameter 11μm Grade CS3J455S
GFPC13 Nittobo's chopped strand glass fiber for PC
Average fiber diameter 13μm Grade CS3PE455S
GFPPE11 Nittobo PPE chopped strand glass fiber
Average fiber diameter 11μm Grade CS3J293S
GFPEEK11 Nittobo's PEEK chopped strand glass fiber
Average fiber diameter 11μm Grade CS3J256S
GFPET11 Nittobo Polyester Chopped Strand Glass Fiber
Average fiber diameter 11μm Grade CS3J941S
Tismo D Made by Otsuka Chemical Co., Ltd. Potassium titanate fiber Average fiber diameter 0.5μm
Mica powder Yamaguchi Mica Industrial Co., Ltd. Grade CS-325DC
Average particle size 30μm

[Thermoplastic resin]
PC (H3000) Mitsubishi Engineering Plastics Polycarbonate (PC) Product name Iupilon H3000
Noryl PPO534 Made by Savic Co., Ltd. Modified PPO (modified polyphenylene oxide) Trademark Noryl Grade Noryl PPO534
PEEK (150PF) Polyether ether ketone (hereinafter PEEK) manufactured by Victrex

[Thermosetting resin]
As the thermosetting resin, an allyl ester resin (AA101, viscosity 630000 cps (30 ° C.) manufactured by Showa Denko KK) was used. Dicumyl peroxide (Nippon Yushi Co., Ltd .: Park Mill D) was used as the organic peroxide.

[Examples 1 to 11 and Comparative Examples 1 to 5]
The raw materials described above were blended and melt kneaded as shown in Tables 1 to 4 below, and resin compositions of Examples 1 to 11 and Comparative Examples 1 to 5 were produced. Various molded articles were prepared using these resin compositions. The details of kneading and molding are as follows.

[Kneading]
For the kneading of the thermoplastic resin, the same direction twin screw extruder (ZE40A × 40D; screw diameter 43 mm, L / D = 37) manufactured by Berstov Co. was used. Carbon fibers and non-conductive fibers (or non-conductive particles) were charged from the hopper and / or side feeder, and thermoplastic resin was charged from the hopper.

As for the kneading conditions, in the case of PEEK, kneading was performed at a resin temperature of 380 ° C. and a screw rotation speed of 100 rpm.
In the case of PC, the resin temperature was 280 ° C. and the screw rotation speed was 100 rpm.
In the case of Noryl PPO534, the resin temperature was 280 ° C. and the screw rotation speed was 100 rpm.

  A lab plast mill manufactured by Toyo Seiki Co., Ltd. was used for kneading the thermosetting resin. First, a powder thermosetting resin prepolymer (thermosetting resin) was charged into the mill, and then carbon fibers and non-conductive fibers were charged.

  The kneading conditions were carried out at a resin temperature of 80 ° C., a mixer rotation speed of 80 rotations, and a kneading time of 10 minutes.

[Molding]
From the various resin compositions of Examples 1 to 11 and Comparative Examples 1 to 5, (1) injection molded bodies, (2) compression molded bodies, and (3) extrusion molded bodies were produced as follows.

(1) Injection molded body (flat plate)
Flat plates (100 × 100 × 2 mm thickness) were molded from the various resin compositions of Examples 1 to 11 and Comparative Examples 1 to 6 using an injection molding machine (F-45) manufactured by Crockner.
In the case of PEEK, the molding conditions were a molding temperature of 400 ° C., a mold temperature of 180 ° C., injection speed: low speed 20 mm / sec, and high speed 100 mm / sec. In the case of PC, the molding temperature was 280 ° C., the mold temperature was 100 ° C., the injection speed was low speed 20 mm / sec, and the high speed was 100 mm / sec.
In the case of Noryl PPO534, the molding temperature was 280 ° C., the mold temperature was 80 ° C., injection speed: low speed 20 mm / sec, high speed 100 mm / sec.
In the case of an allyl ester resin, the molding temperature was 100 ° C., the mold temperature was 150 ° C. for 1 hour, the injection speed was low speed 20 mm / sec, and high speed 100 mm / sec.

(2) Compression molded body (flat plate)
The compression molding was performed by press molding at a molding temperature of 280 ° C. and a press pressure of 200 kgf / cm ² using a thermoforming machine manufactured by Nippon Po Engineering. The shape of the molded product was a flat plate (100 × 100 × 2 mm thickness). The natural cooling in Tables 3 and 4 means that a molded product at a high temperature (immediately after molding) is taken out and left at room temperature, and the cooling press is sandwiched between a hot molded product and a press cooled with water. And cooled for 10 minutes.

(3) Extruded product (round bar)
For extrusion molding, a die (die diameter 150 mm, extrusion diameter 10 mmφ) was used, and a 30 mmφ single screw extruder (manufactured by Souken Co., Ltd.) was used. The extrusion speed was two types, low speed (1 m / h) and high speed (50 m / h). The molding temperature was 280 ° C. for PC and Noryl PPO534, and 370 ° C. for PEEK.

  About the various molded object produced as mentioned above, the measurement of volume specific resistance value and its variation were calculated | required as follows. These results are shown in Tables 1 to 4 below.

(1) Volume resistivity The volume resistivity of the molded body was measured with an insulation resistance meter (“High Resistance Meter R8340” manufactured by Advantest) for a molded body of 10 ⁸ Ω · cm or more. Less than 10 ⁸ Ω · cm was measured by a four-probe method (“Loresta HP MCP-T410” manufactured by Mitsubishi Chemical Corporation).

(2) Variation The volume specific resistance values at four positions selected at random were measured by the method (1) above, and the variations were evaluated according to the following criteria.
○: Variation is within 10 ^{± 1} Ω · cm ×: Variation is 10 ² Ω · cm or more, or variation is 10 ⁻² Ω · cm or less

Considering the results of (1) and (2) above, the resistance change was evaluated as follows.
○: Even if the injection speed in injection molding, the cooling conditions in compression molding, and the extrusion speed in extrusion molding are changed, the average resistance value is within 10 ^{± 2} Ωcm ×: Same as above, but when various conditions are changed Resistance value is 10 ³ Ωcm or more or 10 ^-3 Ω · cm or less

  It can be said that the various molded bodies of Examples 1 to 11 have little resistance change and good reproducibility of volume resistivity. Therefore, according to the resin composition of Examples 1-11, it turns out that volume resistivity can be controlled to a desired value within a semiconductive area | region. In addition, each of the various molded products according to the examples has little variation in the molded product, and the resistance change is small even when the molding conditions change.

Claims (19)

Carbon fiber having an average fiber diameter of 5 to 500 nm, non-conductive fiber having an average fiber diameter of 500 nm or more, and a resin are blended,
The blending ratio X of the carbon fiber is 1 to 20% by mass,
A resin composition in which a blending ratio Y of the nonconductive fibers satisfies a relationship of X <Y. The resin composition according to claim 1, wherein the volume resistivity is in the range of 1 × 10 ⁰ to 1 × 10 ¹² Ωcm. 3. The resin composition according to claim 1, wherein the carbon fiber before blending has an average fiber diameter of 5 to 500 nm, an aspect ratio of 40 or more, and a volume resistivity of 10 ⁻² Ωcm or less.   The resin composition according to any one of claims 1 to 3, wherein the non-conductive fibers before blending are inorganic fibers or organic fibers having an average fiber diameter of 500 nm or more.   The resin before blending is polyethylene, polypropylene, polystyrene, ABS resin, polyacetal, aliphatic polyamide, aromatic polyamide, polyethylene terephthalate, polybutylene terephthalate, polycarbonate, modified polyphenylene ether, polyphenylene sulfide, cycloolefin polymer, liquid crystal polymer, poly It is at least one kind of thermoplastic resin of etherimide, polysulfone, polyethersulfone, polyamideimide, thermoplastic polyimide, polyetherketone, polyetheretherketone, fluororesin or polybenzimidazole. 2. The resin composition according to item 1.   The resin before blending is at least one thermosetting resin of epoxy resin, polyurethane, phenol resin, diallyl phthalate resin, unsaturated polyester resin, urea resin, melamine resin, silicone resin, polyimide resin, allyl ester resin. The resin composition of any one of Claims 1-4. Including a melt-kneading step of introducing and melting and kneading carbon fibers having an average fiber diameter of 5 to 500 nm and non-conductive fibers having an average fiber diameter of 500 nm or more into the resin,
A method for producing a resin composition, wherein the carbon fiber and the non-conductive fiber are introduced into a molten resin made of the resin when the melt kneading. Including a melt-kneading step of introducing and melting and kneading carbon fibers having an average fiber diameter of 5 to 500 nm and non-conductive fibers having an average fiber diameter of 500 nm or more into the resin,
The resin before melt kneading is a polymer particle having a volume average particle size of 200 μm or less,
The method for producing a resin composition, wherein the melt kneading dry-mixes the polymer particles and the carbon fibers and performs melt kneading, and then introduces the non-conductive fibers into the molten resin. It is molded using the resin composition according to any one of claims 1 to 6,
A molded body having a variation in volume resistivity of 10 ^{X ± 1} Ωcm (0 ≦ X ≦ 12) at each of four randomly selected positions.   The molded body according to claim 9, wherein the molded body is an injection molded body, a compression molded body, or an extrusion molded body. A carbon fiber and a non-conductive fiber that can produce an injection-molded body in which the volume resistivity of the injection-molded body varies within a range of 10 ^{X ± 2} Ωcm (0 ≦ X ≦ 12) even if the injection speed is changed; A resin composition containing a resin. A carbon fiber and a non-conductive fiber that can produce a compression-molded body in which the change in volume resistivity of the compression-molded body is in the range of 10 ^{X ± 2} Ωcm (0 ≦ X ≦ 12) even if the cooling conditions are changed; A resin composition containing a resin. Even if the extrusion speed changes, carbon fibers and non-conductive fibers that are capable of producing an extruded product having a volume resistivity change of 10 ^{X ± 2} Ωcm (0 ≦ X ≦ 12) within the range of the extruded product, A resin composition containing a resin.   The molded object shape | molded using the resin composition of any one of Claims 11-13.   A conveying part formed by using the resin composition according to any one of claims 1 to 6 and claims 11 to 13.   The parts for conveyance according to claim 15 used in a clean room.   The heat-resistant sliding member formed using the resin composition of any one of Claims 1-6 and Claims 11-13.   A heat-resistant sliding member obtained by cutting the compression-molded body or extrusion-molded body according to any one of claims 10, 13, and 14, and applicable to any of bearings, gears, and manufacturing machine parts.   An IC test socket, a spin chuck, various rolls used in a copying machine, a seamless belt, an antistatic fiber, an electrostatic coating, using the resin composition according to any one of claims 1 to 18 and various molded articles. Member, fuel tube, fuel peripheral member, chemical tube, IC tray, or carrier tape.