JP2007224209A - Conductive thermoplastic resin molded article - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain sufficient reinforcing effect by formulation of a reinforcing fiber and obtain good conductivity in slight carbon black formulation amount by enhancing developing effect of conductivity by carbon black and further improve mechanical properties thereby, in a conductive thermoplastic resin molded article. <P>SOLUTION: The conductive thermoplastic resin molded article comprises (a) an olefinic resin, (b) an organic filament composed of a resin having polarity and (c) carbon black powder as conductive filler so that the content of the component (a) to total of the component (a) and the component (b) is 60-95 mass% and the content of the component (b) is 5-40 mass% and the content of the component (c) is 5-20 pts.mass based on 100 pts.mass component (c). The resin molded article is obtained by each producing pellets of the component (a) containing the component (b) and pellets of the component (a) containing the component (c), mixing these pellets and then molding the mixed pellets. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention is excellent in electrical conductivity and mechanical properties such as bending strength, flexural modulus and impact strength, and is used for automobile parts, building materials, liquid crystal related or semiconductor related trays, etc. The present invention relates to a conductive thermoplastic resin molded article useful as a weak electrical component.

  Today, resin products are required to have conductivity in various fields. For example, various attempts have been made to impart conductivity in order to develop antistatic properties, electromagnetic shielding, and electrostatic coating properties. Conventionally, it is known that a conductive resin composition and a molded product can be obtained by blending carbon black with a resin. In this case, in order to obtain high conductivity, it is necessary to mix a large amount of carbon black in the resin composition. However, if a large amount of carbon black is filled in the resin, the mechanical properties of the resulting molded product will deteriorate. Is a problem.

  Therefore, in order to balance mechanical properties and conductivity, carbon is added to conductive fiber reinforced composite material (Patent Document 1) in which carbon fiber and carbon black are blended with thermoplastic resin, or fiber reinforced composite material reinforced with glass fiber. A thermoplastic resin composition excellent in electrical properties blended with black (Patent Document 2) has been proposed.

  However, these techniques are insufficient in improving mechanical properties, particularly impact strength. That is, even when carbon fiber or glass fiber is blended, rigidity and elastic modulus are improved, but impact strength is not so much improved. This is because, for example, in a method of kneading glass chopped strands as reinforcing fibers using an ordinary extruder, the fibers are cut short in the kneading process, and the fibers are further broken by injection molding. As a result, even if the rigidity and elastic modulus can be improved, the effect of improving the impact resistance cannot be obtained.

  In Patent Document 1, an extruder having a surface processed with a screw or a cylinder is used to supply continuous carbon fibers to prevent breakage of the fibers in the kneading process, but sufficient effects are not obtained.

  As disclosed in Patent Documents 1 and 2, there is a technique (Patent Document 3) that improves mechanical properties by adopting stamping molding for those mainly for injection molded products. In stamping molding, the long fiber can be filled in the molded product as it is without cutting, so that a good reinforcing effect by the long fiber can be obtained. However, stamping molding has a problem that the molding cycle is longer than that of normal injection molding, and that molding takes time.

In consideration of handling when blending carbon black into resin, a resin blended with carbon black is kneaded in advance, and this is used as a master batch to dry blend with resin that does not contain carbon black before molding. Thus, there is a method of obtaining a conductive resin molded product. However, this method does not sufficiently disperse carbon black, and in order to obtain conductivity, it is necessary to increase the amount of carbon black than usual, and as a result, the mechanical properties of the obtained molded product are reduced. .
JP-A-11-116818 Japanese Patent Publication No.51-45297 Japanese Patent Laid-Open No. 10-158443

  The present invention eliminates the above-mentioned conventional problems, obtains a sufficient reinforcing effect by blending reinforcing fibers, and enhances the effect of developing the conductivity by carbon black, thereby obtaining good conductivity with a small amount of carbon black. Thus, an object of the present invention is to provide a conductive thermoplastic resin molded article that can further improve the mechanical properties.

As a result of intensive studies to solve the above-mentioned problems, the inventors of the present invention used an olefin resin as a matrix resin, blended with organic long fibers made of a resin having polarity, and carbon black powder as a conductive filler. In this case, a conductive thermoplastic resin obtained by mixing and molding an olefin resin pellet containing carbon black powder and an organic long fiber-containing pellet made of a resin having a polarity with the olefin resin as a matrix resin. The present inventors have found that a molded product can solve the above-mentioned problems and have reached the present invention.
That is, the gist of the present invention is as follows.

[1] The following components (a), (b) and (c) are used in which the content of component (a) is 60 to [95% by mass with respect to the sum of component (a) and component (b) (b) The conductive thermoplastic resin molding is contained so that the content is 5 to 40 mass% and the content of the component (c) is 5 to 20 mass parts per 100 mass parts of the component (a). A component (a) pellet containing component (b) (hereinafter referred to as “(a, b) pellet”) and a component (a) pellet containing component (c) (hereinafter “ (A, c) pellets ") are manufactured, and the (a, b) pellets and (a, c) pellets are mixed and then molded. Molding.
(A) Olefin resin (b) Organic long fiber made of resin having polarity (c) Carbon black powder as conductive filler

[2] A conductive thermoplastic resin molded article according to [1], wherein (b) the polar resin constituting the organic long fiber has a melting point of 200 ° C. or higher.

[3] The conductive thermoplastic resin molded article according to [1] or [2], wherein (b) the organic long fiber is a polyester fiber and / or a polyamide fiber.

[4] A conductive thermoplastic resin molded product according to [1] to [3], wherein (a) the olefin resin is a propylene resin.

[5] The conductive thermoplastic resin molded product according to [1] to [4], wherein (b) the average fiber length of the organic long fibers is 4 mm or more.

[6] In [1] to [5], the (a, b) pellet is obtained by (b) impregnating (a) an olefin-based resin into a roving of an organic long fiber, and then drawing and then cutting. An electrically conductive thermoplastic resin molded product characterized by that.

[7] A conductive thermoplastic resin molded product according to [1] to [6], which is an injection molded product.

  If the conductive thermoplastic resin molded article of the present invention containing carbon black powder as an organic long fiber composed of an olefin resin and a polar resin and a conductive filler, with a good reinforcing effect by the organic long fiber, Excellent mechanical properties can be obtained, and high conductivity can be expressed with a small amount of carbon black powder due to the following effects due to organic long fibers made of a polar resin. Therefore, it is possible to sufficiently improve the mechanical characteristics by reducing the blending amount of carbon black powder.

  That is, in the conductive thermoplastic resin molded article of the present invention, organic long fibers made of a resin having polarity together with carbon black powder are dispersed in a three-dimensional manner in a resin matrix made of an olefin resin that is a nonpolar resin. However, the carbon black powder in the molded article is attracted to the organic long fiber made of a polar resin and is localized around the organic long fiber. And, in this way, the carbon black powder is localized around the organic long fiber, so that it is higher with the blending of the same amount of carbon black powder than when the carbon black powder is simply dispersed in the olefin resin. Conductivity can be obtained.

  In addition, the organic long fiber is superior in elasticity and ductility as compared with the glass fiber and the carbon fiber, and thus is not easily damaged in the molding process. For this reason, the length of the organic long fiber is sufficiently maintained in the molded product, and an excellent reinforcing effect by the organic long fiber can be obtained.

  Moreover, when molding such a conductive thermoplastic resin molded article, (a, c) pellets, which are master batches in which carbon black powder is contained in an olefin resin, and organic long fibers made of a resin having polarity are used. (A, b) pellets, which are pellets of the olefin resin to be contained, are prepared, and the (a, c) pellets and (a, b) pellets are mixed and supplied to a molding machine for molding. Therefore, remarkably good conductivity can be expressed easily and with a small amount of carbon black powder. Moreover, the mixing ratio of the (a, c) pellets and the (a, b) pellets can be easily changed, whereby the conductive performance of the obtained molded product can be easily and arbitrarily controlled.

  As described above, the details of the mechanism of action that can improve the conductivity development effect by manufacturing (a, b) pellets and (a, c) pellets, and mixing and molding them are not clear. As will be described later, (a, b) pellets uniformly and sufficiently impregnated with olefin-based resin in a state where organic long fibers made of a resin having polarity are aligned, and carbon in a high concentration and uniformly dispersed state By mixing the (a, c) pellets containing the black powder, these are directly collided, mixed and kneaded, and the carbon black powder in the (a, c) pellets in the melt molding step (a, c) b) The frequency of contact with the organic long fibers in the pellet is increased, and as described above, the amount of carbon black powder localized around the organic long fibers is increased, and as a result, carbon via the organic long fibers is increased. Good conductivity network rack powder is considered to be due to so formed.

  The conductive thermoplastic resin molded article of the present invention is excellent in conductive performance, and is also excellent in mechanical properties such as bending strength, bending elastic modulus, impact strength, etc. It is extremely useful industrially as a molded product such as a weak electric component such as a tray used in a liquid crystal or semiconductor relationship.

  Hereinafter, embodiments of the conductive thermoplastic resin molded article of the present invention will be described in detail.

[(A) Olefin resin]
There is no restriction | limiting in particular as (a) olefin resin used by this invention, Various olefin resin can be used. For example, ethylene homopolymer; vinyl monomers such as propylene, 1-butene and other α-olefins, vinyl acetate, (meth) acrylic acid, (meth) acrylic acid ester, etc., mainly composed of ethylene 1 type or 2 types of ethylene-type resin, such as a copolymer with 1 type, or 2 or more types of these; Propylene homopolymer; Other alpha-olefins, such as ethylene and 1-butene which made propylene the main component Propylene-based resins such as copolymers with the above; 1-butene homopolymer; 1-butene as the main component, and other α-olefins such as ethylene, propylene, etc. Butene-based resins such as polymers; and the like. These olefin-based resins may be homopolymers or copolymers, may be random copolymers, or may be block copolymers.
In addition, said "main component" refers to what is contained in an olefin resin 50weight% or more, Preferably it is 60weight% or more.

  Among these, a propylene-based resin is preferable from the viewpoint of excellent heat resistance, and specific examples thereof include, for example, a propylene homopolymer, or a propylene-ethylene random copolymer resin mainly composed of propylene, propylene-ethylene. Examples thereof include a block copolymer resin.

  As the polymerization mode of the olefin resin, any polymerization mode may be adopted as long as a resinous material can be obtained, but a gas phase method or a solution method is particularly preferable.

  As the olefin resin, the lower limit of the melt flow rate measured at a temperature of 230 ° C. and a load of 21.18 N in accordance with JIS K7210 is preferably 0.05 g / 10 minutes, and preferably 0.1 g / 10 minutes. Is particularly preferable, and the upper limit is preferably 200 g / 10 minutes, and particularly preferably 100 g / 10 minutes. If the melt flow rate is at least the above lower limit, the molding processability as a material to be molded is improved, and the surface appearance of the resulting molded product tends to be good, whereas the one below the above upper limit, The mechanical strength of the obtained molded product and the dispersion of organic long fibers tend to be good.

  In the conductive thermoplastic resin molded article of the present invention, only one kind of the olefin resin of component (a) may be contained, or two or more kinds thereof may be mixed and contained.

[(B) Organic long fiber made of a polar resin]
The resin constituting the organic long fiber comprising the resin having polarity (b) used in the present invention is not particularly limited as long as it has polarity, and various resins can be exemplified.
Here, the term “polar” refers to a resin that is more polar than the non-polar component (a) olefin resin.

Examples of organic long fibers made of a polar resin include, for example, polyester fibers, polyamide fibers, polyurethane fibers, polyacrylonitrile fibers, and the like.
In the conductive thermoplastic resin molded article of the present invention, only one organic long fiber may be included, or two or more organic long fibers may be mixed and included.

  If the fiber diameter of the organic long fiber is too large, the Izod impact strength of the molded product is lowered. It is considered that nano-sized fibers can be used when the fiber diameter is thin, and may be very good depending on the application of the molded product. Since the fiber diameter used in this way is wide, the number of fibers used cannot be defined, but when considering the cross-sectional area of the bundle of fibers, the cross-sectional area in the direction almost perpendicular to the fibers of the pellet is usually 5-60. % Of the fiber cross-sectional area.

  By the way, when molding the conductive thermoplastic resin molded article of the present invention by injection molding, since it is performed at a molding temperature equal to or higher than the melting point of the olefin resin of the component (a), the organic long fiber does not melt even by injection molding. It is preferable to use one of temperature. That is, the melting point of the component (a) olefin resin is usually about 70 to 170 ° C., and therefore the molding temperature (referred to as the outlet temperature of the molding machine) is about 150 to 210 ° C. As the material of the organic long fiber as the component (b), a material having a melting point higher than this molding temperature by 10 ° C. or more, preferably 20 ° C. or more produces a good result.

  In addition, in the molding process, the carbon transition temperature of the material of the organic long fiber is the molding temperature so that the carbon black powder is attracted to the organic long fiber side and the conductivity improvement effect due to the localization of the carbon black powder is sufficiently obtained. Or lower (preferably lower by 5 ° C. or more). That is, if the glass transition point of the organic long fiber is lower than the molding temperature, the molecular mobility on the surface of the organic long fiber is increased during the molding process, and the carbon black powder is more likely to gather on the organic long fiber side. The specific glass transition temperature of the organic long fiber is usually preferably 150 ° C. or lower.

  (B) The organic long fiber is preferably a polyester fiber, a polyamide fiber, more preferably a PET (polyethylene terephthalate) fiber (melting point 260 ° C., glass transition temperature 67 ° C.), a PEN (polyethylene naphthalate) fiber (melting point 272). C., glass transition temperature 113.degree. C.), particularly preferably PEN fiber. That is, when polyester fiber, polyamide fiber, especially PET fiber or PEN fiber, especially PEN fiber is used, the dispersion of the fiber in the injection-molded product is good and the physical properties as the fiber are high. Goods are obtained.

  (B) The length of the organic long fiber corresponds to the length of the (a, b) pellet according to the present invention described later, and (a, b) the average fiber length of the organic long fiber contained in the pellet is preferable. Is 4 mm to 50 mm, more preferably 4 mm to 20 mm, and particularly preferably 4 mm to 10 mm. When the average fiber length of the organic long fibers is less than 4 mm, the effect of improving the impact strength cannot be sufficiently obtained, and when the average fiber length exceeds 50 mm, molding becomes difficult.

In the conductive thermoplastic resin molded article of the present invention, the content of the organic long fiber (b) composed of a resin having polarity is such that the component (a) is based on the total amount of the component (a) and the component (b). It is essential that the component (b) is in the range of 5 to 40% by mass at 60 to 95% by mass. Preferably component (a) is 65 to 90% by mass, component (b) is 10 to 35% by mass, more preferably component (a) is 70 to 10% by mass and component (b) is 10 to 30% by mass.
When the content of (b) organic long fibers is less than the above range, the effect of improving the mechanical strength is poor, and when the content is large, the dispersion of fibers in the final molded product is deteriorated, resulting in poor product appearance. .

[(C) Carbon black powder]
Examples of (c) carbon black powder as the conductive filler include furnace black, acetylene black, thermal black, and channel black. Among these, highly conductive acetylene black and furnace black, which can provide conductivity when added in a small amount, are preferable.
In the conductive thermoplastic resin molded article of the present invention, the carbon black powder of component (c) may contain only one of them, or two or more of them may be mixed and contained.

When (c) DBP oil absorption of the carbon black powder is less than 50 cm ^3/100 g, because the conductivity even when a large amount of carbon black added is hardly expressed, DBP oil absorption of the carbon black powder 50 cm ^3/100 g or more It is preferable that it is 100 cm < ³ > / 100g or more especially.

  It is essential that the content of the component (c) in the conductive thermoplastic resin molded article of the present invention is 5 to 20 parts by mass per 100 parts by mass of the component (a). Preferably, the component (c) is 5 to 15 parts by mass, more preferably 5 to 10 parts by mass per 100 parts by mass of the component (a). When the component (c) is less than 5 parts by mass per 100 parts by mass of the component (a), the necessary conductivity cannot be obtained, and when it exceeds 20 parts by mass, the mechanical properties are significantly deteriorated.

In addition, the volume specific resistance value required as the conductive material targeted by the present invention indicates 10 ⁸ (Ω · cm) or less. In general, a conductive material of 10 ⁸ (Ω · cm) or less, 10 ⁴ (Ω · cm) or more is called an antistatic material, and 10 ⁴ (Ω · cm) or less, 10 ⁰ (Ω · cm) or more. Is referred to as a conductive material, and 10 ⁰ (Ω · cm) or less is referred to as a highly conductive material. For example 10 ⁸ in automotive parts (Ω · cm) or less, 10 ⁴ (Ω · cm) or more antistatic material region, 10 ⁴ in the electrode material (Ω · cm) or less, 10 ⁰ (Ω · cm) or higher The conductive material region is generally required.

[Other ingredients]
The conductive thermoplastic resin molded article of the present invention contains the above-mentioned components (a), (b) and (c) as essential components, but is further thermoplastic as long as the effects of the present invention are not impaired. You may contain components, such as resin, rubber | gum, an additive, a filler. However, the conductive thermoplastic resin molded article of the present invention preferably contains 50% by mass or more of the essential components (a) to (c), and preferably contains 80% by mass or more. Particularly preferred.

  Examples of the additive include an antioxidant, a heat stabilizer, a light stabilizer, an ultraviolet absorber, a neutralizer, a lubricant, an antifogging agent, an antiblocking agent, a dispersant, a flame retardant, a colorant, and a heat agent. The various additives etc. which are normally used for a plastic resin can be mentioned.

  Among these, examples of the antioxidant include monophenol type, bisphenol type, tri- or higher polyphenol type, thiobisphenol type, naphthylamine type, diphenylamine type, and phenylenediamine type. Among these, monophenol-based, bisphenol-based, tri- or higher polyphenol-based, and thiobisphenol-based antioxidants are preferable because of their high antioxidant effects. When using antioxidant, it is 0.01-5 mass% normally with respect to the total amount of component (a)-(c), Preferably 0.05-3 mass% is used. If the antioxidant is above the above lower limit, the antioxidant effect due to the use of the antioxidant is more easily expressed effectively, and if it is below the above upper limit, an effect commensurate with the amount of use is obtained and economical. In addition, there is little risk of coloration.

  Examples of the filler include talc, mica, silica, titania, calcium carbonate, and various fillers usually used for thermoplastic resins.

[Method for producing conductive thermoplastic resin molded product]
(1) (a, b) Pellet manufacturing method (a, b) Pellet, that is, (b) Olefin-based resin pellets containing organic long fibers made of resin having polarity are polar resins It is manufactured by impregnating an olefin resin into a roving of an organic long fiber and then drawing it, and then cutting it into a pellet of preferably 4 mm to 50 mm, more preferably 4 mm to 20 mm, particularly preferably 4 mm to 10 mm. can do.

  Here, the method of impregnating the olefin resin is not particularly limited, and a method of heating the organic long fiber roving to a temperature higher than the melting point of the resin after passing through the resin powder fluidized bed (Japanese Patent Publication No. 52-3985). A method of impregnating an organic long fiber roving with a molten olefin resin using a crosshead die (JP-A-62-260625, JP-A-63-132036, JP-A-63-264326, JP-A-1-208118); Any method may be used, such as a method in which polyolefin resin fibers are used and roving of the organic long fibers is simultaneously focused and then heated to a temperature higher than the melting point of the resin (Japanese Patent Laid-Open No. 61-118235).

  Since the fiber length of the organic long fiber in the conductive thermoplastic resin molded article of the present invention is equal to the pellet length produced in this way, it can be obtained by adjusting the cut length in producing the pellet. It is possible to control the fiber length of the organic long fiber in the formed conductive thermoplastic resin molded product.

(2) (a, c) Manufacturing method of pellets (a, c) Pellet, that is, (c) Pellet of (a) olefin resin containing carbon black powder is obtained by resinizing carbon black powder and olefin resin. It is kneaded at a melting temperature or higher, cooled, and then formed into pellets. As a kneading apparatus, known apparatuses such as a short-screw extruder, a twin-screw extruder, a two-roll mill, a Banbury mixer, an intermix, and a pressure kneader can be used.

(3) Mixing method of (a, b) pellets and (a, c) pellets A known method is used as a mixing method of (a, b) pellets and (a, c) pellets. For example, there is a dry blending method using a mixer such as a Henschel mixer or a tumbler.

(4) Molding method Molding of the conductive thermoplastic resin molded article of the present invention can be performed using various general molding machines having a screw plasticizing mechanism.
The conductive thermoplastic resin molded product of the present invention uses organic long fibers that are hard to break even if the kneading of the screw is strong as the reinforcing fiber. Injection molding can be performed. More specifically, using a high-kneading type screw containing subflight or dull mage, etc., it can be molded by a method such as molding after applying back pressure and low screw speed over time. preferable.

  In the present invention, (a, b) pellets, (a, c) pellets, and olefin resin pellets containing neither carbon black powder nor organic long fibers are mixed and molded to be conductive. Although it is conceivable to obtain a thermoplastic resin molded article, preferably, (a, c) pellets are produced with the total amount of the required amount of carbon black powder, and organic long fibers made of a resin having the required amount of polarity are used. The effects of the present invention can be obtained by producing pellets (a, b) in the total amount and mixing these (a, c) pellets and (a, b) pellets alone to form a conductive thermoplastic resin molded article. Preferred above. In addition, when adding the above-mentioned various additives other than carbon black powder, organic long fiber, and olefin resin, these may be added to either (a, b) pellets or (a, c) pellets, Preferably, blending with (a, b) pellets is advantageous in terms of conductivity when the (a, b) pellets and (a, c) pellets are mixed.

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples unless it exceeds the gist.
The materials and evaluation methods used in the examples and comparative examples are as follows.

[Materials used]
Component (a-1): Propylene homopolymer resin (“SA06A” manufactured by Nippon Polypro Co., Ltd.)
Melt flow rate 60 g / 10 min (230 ° C., 21.2 N load))
Component (b-1): PET fiber (“P900M BHT1670T250” manufactured by Teijin, average
(Fiber diameter 25μm)
Component (b-2): PEN fiber (manufactured by Teijin "Q900N BHT1670T250", average
(Fiber diameter 25μm)
Component (c-1): Carbon black powder (Ketjen Black E “Ketjen Black E”
C ", DBP oil absorption of 360cm ³ / 100g)
Ingredient (x-1): Carbon fiber ("Torayca" manufactured by Toray)

[Evaluation methods]
<Bending elastic modulus>
A bar of 1/8 inch mm × width 1/2 mm × length 5.0 inch obtained by molding was measured under the following conditions in accordance with ASTM-D-790 method.
Test speed: 2 mm / min
Distance between fulcrums: 100mm

<Izod impact strength>
In accordance with ASTM-D-256 method, a bar of 1/8 inch mm × width 1/2 mm × length 5.0 inch obtained by molding is cut into a half length of 2.5 inches. The measurement was performed under the following conditions.
Notch rotation speed: 400rpm
Notch feed speed: 120 mm / min
Hammer capacity: 60kgf · cm

<Volume resistivity>
Cut the both ends of the bar of 1/8 inch mm × width 1/2 mm × length 5.0 inch obtained by molding, adjust it to 10 cm, apply conductive paste to the cut end surface, and measure volume resistivity A sample was used. About this sample, resistance value was measured using the digital multimeter (made by Yokogawa M & C Co., Ltd.), and the volume specific resistance value was calculated | required by calculation with the following formula from the obtained measured value.
Volume resistivity = (measured value / sample bar length) x cross-sectional area

<Appearance>
The surface of a flat plate of 80 mm × 100 mm × 2.0 mm thickness obtained by molding was visually observed and evaluated according to the following criteria.
○: The fiber dispersion is the best, the bundle of unopened fibers is hardly visible, and the flat plate surface is smooth.
(Triangle | delta): The bundle | flux of the fiber which is not opened is seen for a while, and a flat surface has a slight unevenness.
X: Many bundles of unopened fibers are seen, and the flat plate surface is rough.

[Production example]
<Production Example 1: Production of long fiber-containing olefin resin pellet>
Component (a-1) A propylene homopolymer resin and the long fiber component shown in Table 1 were mixed into the twin-screw extruder (JSW “TEX30”, L / D = 42, Drawing was performed using a cylinder diameter of 30 mm, a cylinder temperature of 190 to 220 ° C., and a cross die head temperature of 220 ° C. to produce long fiber reinforced polyolefin resin pellets (components A-1 to 6, X-1). The pellet length was adjusted to 8 mm.

<Production Example 2: Production of olefin resin pellets containing long fiber / carbon black>
Component (a-1) a propylene homopolymer resin, a long fiber component shown in Table 1, and a component (c-1) carbon black are blended as shown in Table 1 and have a crosshead die (manufactured by JSW “ Tex30 ”, L / D = 42, cylinder diameter 30 mm, cylinder temperature: 190 to 220 ° C., cross die head temperature: 220 ° C., and then subjected to pultrusion molding, long fiber reinforced carbon black-containing polyolefin resin pellets (component X-2) ) Was manufactured. The pellet length was adjusted to 8 mm.

<Production Example 3: Production of carbon master batch>
A predetermined amount of the component (a-1) propylene homopolymer resin and the component (c-1) carbon black powder are twin-screw extruder (“TEX30” manufactured by JSW, L / D = 42, cylinder diameter 30 mm, cylinder temperature: 160 To 240 ° C.) to produce a carbon master batch (component C, carbon black powder content 20 mass%).

[Examples and Comparative Examples]
<Examples 1-3, Comparative Examples 3-6>
Each of the long fiber-containing polyolefin resin pellets was dry blended with a carbon masterbatch using a tumbler with the material composition shown in Table 1, and then subjected to an injection molding machine. The cylinder temperature was 210 ° C, the mold temperature was 70 ° C, and the back pressure was A flat plate of 80 mm × 100 mm × thickness 2.0 mm and a bar of thickness 1/8 inch mm × width 1/2 mm × length 5.0 inch were respectively formed at 10 kg and a screw rotation speed of 50 rpm.
Table 2 shows the evaluation results of the obtained molded product.

<Comparative Examples 1 and 2>
Component (a-1) which is not impregnated with organic long fiber (a-1) A propylene homopolymer resin and a carbon masterbatch are dry blended with the material composition shown in Table 2 and then subjected to an injection molding machine. Molding and evaluation were performed in the same manner as in Example 1 except that molding was performed at 40 ° C., a back pressure of 10 kg, and a screw rotation speed of 50 rpm, and the results are shown in Table 2.

<Comparative Example 7>
Component (a-1) not impregnated with organic long fiber (a-1) Propylene homopolymer resin and long fiber / carbon black-containing olefin resin pellets are dry blended with the material composition shown in Table 2, and then subjected to injection molding machine and molded Molding and evaluation were performed in the same manner as in Example 1 except that the above was performed, and the results are shown in Table 2.
The appearance (×) and volume resistivity (−) in this comparative example are due to large dispersion due to poor dispersion of carbon black and PET fibers.

  From Table 2, it can be seen that according to the present invention, a molded product having excellent electrical conductivity, excellent mechanical properties such as flexural modulus and impact strength, and good molded product appearance can be obtained.

Claims (7)

In the following components (a), (b) and (c), the content of the component (a) with respect to the sum of the components (a) and (b) is 60 to 95% by mass, and the content of the component (b) is It is 5-40 mass%, and it is a conductive thermoplastic resin molded product contained so that content of a component (c) may be 5-20 mass parts per 100 mass parts of a component (a),
Component (a) pellets containing component (b) (hereinafter referred to as “(a, b) pellets”) and component (a) pellets containing component (c) (hereinafter “(a, c)” A conductive thermoplastic resin molded article obtained by molding each of the above (a, b) pellets and (a, c) pellets and then molding.
(A) Olefin resin (b) Organic long fiber made of resin having polarity (c) Carbon black powder as conductive filler   2. The conductive thermoplastic resin molded article according to claim 1, wherein (b) a resin having polarity constituting the organic long fiber has a melting point of 200 ° C. or higher.   3. The conductive thermoplastic resin molded article according to claim 1, wherein (b) the organic long fiber is a polyester fiber and / or a polyamide fiber.   The conductive thermoplastic resin molded article according to any one of claims 1 to 3, wherein (a) the olefin resin is a propylene resin.   The conductive thermoplastic resin molded article according to any one of claims 1 to 4, wherein (b) an average fiber length of the organic long fibers is 4 mm or more.   6. The pellet (a, b) according to any one of claims 1 to 5, wherein (a) an organic long fiber roving is impregnated with (a) an olefin-based resin, and then pultruded and then cut. An electrically conductive thermoplastic resin molded product characterized by that.   The conductive thermoplastic resin molded article according to any one of claims 1 to 6, which is an injection molded article.