JPH11116818A - Electrically conductive thermoplastic resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject composition having a specific oil absorptivity, sufficient electrical conductivity and impact strength necessary for housing material, etc., for electronic equipment and exhibiting excellent fluidity in molding by compounding a thermoplastic resin with electrically conductive fiber and black carbon. SOLUTION: The objective composition is produced by compounding a thermoplastic resin with preferably 5-45 wt.% of electrically conductive fiber such as carbon fiber and preferably 0.5-20 wt.% of a black carbon such as carbon black or graphite having a dibutyl phthalate(DBP) oil absorption of <=250 mL/100 g determined in conformity to JIS K6221A.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conductive thermoplastic resin composition having conductivity and impact strength useful for housing materials of electronic equipment and having excellent fluidity during molding.

[0002]

2. Description of the Related Art In recent years, portable electric and electronic devices such as personal computers and telephones have been widely used, and lightening and thinning of their housing materials have been required. In addition, impact strength and bending characteristics that do not easily break are also required. Among them, the conductive thermoplastic resin composition is applied because of its excellent moldability and weight reduction.

As the conductive thermoplastic resin composition used in the above, there is a molded article made of the thermoplastic resin composition which is provided with a conductive paint or metal plating. There was a problem. Therefore, conductive thermoplastic resins in which conductive materials such as carbon and metal are blended in thermoplastic resins have come to be mainly used. As the conductive material, carbon fiber is mainly used because of its light weight and excellent mechanical properties.

[0004] As the conductive thermoplastic resin composition containing the carbon fiber, it is important to disperse the carbon fiber in the composition for a long time and uniformly to obtain conductivity and mechanical properties. In the method of kneading the thermoplastic resin and the chopped strand carbon fiber using a machine, the carbon fiber breaks shortly, and is further broken short in the molding process such as injection molding, so that the above-described conductivity and mechanical properties are sufficiently exhibited. Can not.

[0005] As a measure for preventing breakage when such a carbon fiber is contained in a thermoplastic resin, Japanese Patent Publication No. 63-36969 has been proposed.
No. 4 proposes a pultrusion method (pultruding method) in which continuous fibers are coated with a thermoplastic resin. In this method, the carbon fiber becomes long and can exhibit sufficient conductivity and mechanical properties, but the productivity is poor in the pultrusion method, and the obtained carbon fiber-containing conductive thermoplastic resin is produced by injection molding or the like. There was a problem that the fluidity during molding was poor.

As measures for increasing the conductivity, Japanese Patent Application Laid-Open Nos. 2-41364 and 4-27938 propose that carbon fibers are used in combination with metal fibers. However, the combined use of metal fibers has the drawback that the weight of the composition is increased and the production cost is increased.

Further, Japanese Patent Application Laid-Open No. 9-87417 proposes to use carbon fiber and carbon black in combination. However, some carbon blacks deteriorate the fluidity and mechanical properties. Carbon black, which is easy to form and develop a chain structure excellent in imparting, has a large adverse effect.

[0008]

Therefore, in the present invention,
It is an object of the present invention to provide a conductive thermoplastic resin composition which has excellent conductivity and mechanical properties, is lightweight and has excellent fluidity during molding, and a method for producing the same.

[0009]

That is, the present invention provides:
(1) A conductive thermoplastic resin composition obtained by compounding a conductive fiber and black carbon with a thermoplastic resin, and having a dibutyl phthalate (DBP) oil absorption of the black carbon to be compounded by the JIS K6221A method. 250ml / 1
(2) conductive thermoplastic resin composition according to the above (1), wherein the conductive fibers are carbon fibers; (3) conductive thermoplastic resin composition of 5 to 5 g (4) The conductive thermoplastic resin composition according to the above (1) or (2), comprising 45 wt% of conductive fibers and 0.5 to 20 wt% of black carbon, and (4) particles having an average diameter of 31.
The conductive thermoplastic resin composition according to any one of the above (1) to (3), wherein black carbon of at least nm is used, and (5) the black carbon is at least one selected from carbon black and graphite. The conductive thermoplastic resin composition according to any one of the above (1) to (4).

(5) Relationship between weight average fiber length (Lw) and fiber diameter (d) of conductive fibers in the composition (Lw / d)
Is 25 to 500, and the ratio of the weight average fiber length (Lw) to the number average fiber length (Ln) is 1.1 or more.
5. The conductive thermoplastic resin composition according to any one of (4) to (6).
A housing material for an electric / electronic device comprising the conductive thermoplastic resin composition according to any one of the above (1) to (5).

(7) Using an extruder provided with an opening / fiber length control mechanism in which at least a part of a screw and / or a cylinder is deformed on the surface, a thermoplastic resin is melted, and the molten resin is melted into the molten resin. The conductive fiber is supplied in a continuous state, and the conductive fiber is spread and cut while passing through the fiber opening / fiber length control mechanism, dispersed in a resin, and discharged from an extruder. A method for producing a conductive thermoplastic resin composition, which comprises producing the conductive thermoplastic resin composition according to any one of (1) to (5).

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be specifically described below.

[0013] The conductive thermoplastic resin composition of the present invention is intended to improve conductivity without deteriorating mechanical properties or fluidity during molding by blending a specific black carbon. Using an absorpt meter according to the JIS K6221A method as carbon, DBP oil absorption 250 ml / 100 per 100 g determined from 70% of the maximum torque when dimethyl phthalate (DBP) is added to black carbon.
g or less, more preferably 200 ml / 100 g or less black carbon.

[0014] In general, black carbon is mainly composed of a plate-like body in which carbon atoms are bonded in a cyclic manner and layer surfaces formed on a hexagonal mesh plane are vertically stacked, and include amorphous carbon, graphite and the like. Among them, examples of the black carbon that can be preferably used in the present invention include carbon black and graphite.

The conductivity of black carbon, especially carbon black, is obtained by the development of a chain structure (structure) due to the connection of carbon black particles. When only carbon black is blended with a thermoplastic resin, the structure is remarkably developed. The smaller the material, the more conductive it is. It is said that this structure has a larger oil absorption of dibutyl phthalate (DBP) and a smaller particle diameter, and is more likely to develop. However, when blended with a thermoplastic resin in combination with a conductive fiber such as carbon fiber to exhibit conductivity, carbon black, which has the opposite effect and has small structure development, has a small amount of conductive effect. And found that the decrease in mechanical properties and fluidity during molding is small, and this is the greatest feature of the present invention.

The black carbon used in the present invention preferably has an arithmetic average particle diameter of 31 nm or more, and more preferably 35 nm or more, as determined by electron microscopy. The particle size of carbon black is determined by burning carbon black, pellets or molded products before blending at 450 ° C. for 5 hours in an argon gas atmosphere, and observing the particle size of carbon black and the like contained in ash remaining by electron microscopy. It is required by doing.

The conductive fibers used in the present invention are not particularly limited as long as they are conductive fibers.
Considering the weight reduction, the mechanical properties of the fiber, the reinforcing effect when blended with the thermoplastic resin, etc., carbon fiber is most preferable.
There is no problem with both AN-based and pitch-based carbon fibers.

The amount of the conductive fiber and the black carbon is 5 to 45 wt% based on the total composition.
%, Black carbon is preferable from the viewpoints of conductivity, fluidity at the time of molding, and mechanical properties of the composition from which 0.5 to 20 wt% is obtained.

As for the length of the conductive fiber, the longer the fiber, the more advantageous for the conductivity and the mechanical properties. However, the shorter the fiber, the better the flowability during molding. Fibers are broken by molding processes such as compounding and injection molding. For this reason, as the fiber length of the conductive fiber, the relationship (Lw / d) between the weight average fiber length (Lw) and the fiber diameter (d) is preferably 25 to 500, and more preferably 30 to 300. Good. (Lw / d)
If the particle size is too small, the conductivity and mechanical properties tend to be inferior. If the particle size is too large, the fluidity at the time of molding deteriorates, and the conductive fibers may become entangled with each other to hinder uniform dispersion. The ratio (Lw / Ln) between the weight average fiber length (Lw) and the number average fiber length (Ln) of the conductive fibers is preferably 1.1 or more. The fiber diameter is preferably 1 to 30 μm, more preferably 4 to 15 μm.

Here, the weight average fiber length (Lw) and the number average fiber length (Ln) are each defined as follows.

Weight average fiber length (Lw) = Σ (ρπr ² Li ² ) / Σ (ρπ ² Li) = ΣLi ² / ΣLi Number average fiber length (Ln) = ΣLi / n where ρ: density of conductive fiber r: radius of the conductive fiber Li: length of the conductive fiber on the i-th surface n: number of the conductive fiber Note that the conductive fiber is a pellet or a molded product at 450 ° C. ×
The measurement was made by microscopic observation of 500 or more conductive fibers from the ash remaining after burning in an argon gas atmosphere for 5 hours.

The thermoplastic resin composition used in the conductive thermoplastic resin composition of the present invention is not particularly limited as long as it can be molded by an extruder. Examples thereof include polyethylene, polypropylene, and polychlorinated thermoplastic resin. vinyl,
Olefinic (co) polymers such as polyvinylidene chloride, polystyrene, styrene-butadiene-acrylonitrile copolymer, aliphatic nylons such as nylon 11, nylon 12, nylon 6, and nylon 66; aliphatic nylons and terephthalic acid Aromatic polyamide which is a copolymer,
Other polyamides such as various copolymerized polyamides, polycarbonates, polyacetals, polymethyl methacrylates, polysulfones, polyphenylene oxides, polyesters such as polybutylene terephthalate, polypropylene terephthalate, polyethylene terephthalate, polycyclohexanediethylene terephthalate, and polybutylene naphthalate, and their copolymers. Polymers, copolymerized polyesters having hard segments of the polyesters and soft segments of polyethers such as polytetramethylene glycol and polyesters such as polycaprolactone, and thermotropic liquid crystal polyesters as described in JP-B-3-72099 Such as thermotropic liquid crystal polymers, polyphenylene sulfide, polyether ether ketone, etc. Emissions, polyether sulfone, polyetherimide, polyamideimide, polyimide, polyurethane, polyether amide, and polyester amides, etc. These can be used alone or in combination of two or more.

The most preferred resins are polybutylene terephthalate, polyethylene terephthalate, polycyclohexane dimethylene terephthalate, polyethylene terephthalate copolymer liquid crystal polymer, nylon 11, nylon 12, nylon 6, nylon 66, aromatic nylon,
Polyphenylene sulfide, ABS resin.

Further, a flame retardant or a flame retardant auxiliary may be added to these thermoplastic resins.

The conductive thermoplastic resin composition of the present invention having the above-mentioned properties can be produced as follows.

That is, as the extruder, an extruder having a fiber opening / fiber length control mechanism in which at least a part of a screw and / or a cylinder is surface-deformed is used, and a thermoplastic resin is supplied to the extruder. Melted, and supply continuous conductive fibers into the molten resin to open
This is a method in which the fiber is opened and cut by a fiber length control mechanism, uniformly dispersed in a molten resin, and extruded from an extruder. According to such a production method, the ratio (Lw / L) of the weight average fiber length (Lw) and the number average fiber length (Ln) of the conductive fibers in the resin composition is obtained.
n) is usually 1.1 or more. In addition, in such a method, the supply timing of black carbon is arbitrary, and it is possible to supply black carbon simultaneously or separately with the thermoplastic resin.

The extruder is supplied with continuous conductive fibers, and specifically, it is preferable to use a roving in which continuous single fibers are bundled. The fiber diameter is preferably 1 to 30 μm, more preferably 4 to 15 μm. The number of bundled fibers is not particularly limited, but a bundle of 10 to 50,000 monofilament monofilaments is preferable from the viewpoint of handling. In addition, these conductive fibers can be used after being subjected to a surface treatment for improving the interfacial adhesion with a resin.

The extruder which can be preferably used in the present invention is a single-screw or multi-screw screw type in which the above-mentioned continuous conductive fiber is spread and a screw and / or a cylinder is processed so as to control the fiber length. An extruder that includes a mechanism for controlling the degree of opening of the continuous fibrous reinforcing material and the fiber length inside the extruder. The continuous conductive fiber is wound into the extruder cylinder at a constant speed by a shear force between the screw flight and the cylinder, and advances while being wound around the screw. Normally, the resin flows through the groove of the screw, but in the above method, the conductive fiber advances over the screw flight. Therefore, by performing various processes on the outer peripheral portion of the screw and the inner wall of the cylinder, it is possible to exert a “comb” effect between the screw and the cylinder on the conductive fiber wound around the screw. As a specific example of the control mechanism, a screw surface, preferably an elliptical screw surface such as a cylindrical screw surface or a neutral element, is subjected to unevenness processing. The method for forming the irregularities is not particularly limited, but cutting, grinding, blasting, or the like can be employed. In addition, as the uneven shape, FIG.
a screw or cylinder 3 as shown in a, b,
A screw 5 or a cylinder 7 as shown in FIGS. 1c and 1d is preferably mentioned, and the screw 1 or the cylinder 3 in FIGS. 4 and
The screw 5 or cylinder 7 in FIGS. 1c and 1d has a mesh 6,6. In particular, an edge-shaped one is preferred because the fiber length can be controlled longer. FIG. 3a shows an example of a full flight screw 9 having an edge processing portion 10 on a flight, and FIG. 3b shows an example of a full flight screw 11 having a mesh processing portion 12 on a flight.

As shown in FIG. 2, the edge-shaped portions 2 and 4 indicate a specific edge angle (θ), the height (h) of the peak and the valley bottom of the uneven shape, and the distance between the peak and the adjacent peak. It can be represented by pitch (t). The specific edge angle (θ) is 60
Degrees or less is desirable, and especially 45 degrees or less is preferred. The height (h) of the peaks and valleys of the uneven shape is preferably 30 times or more the fiber diameter, and more preferably 75 times or more. If the edge angle of the blade processing is too large or trapezoidal, or if the ratio of the height of the peaks and valleys to the fiber diameter is too small, the effect of the conductive fibers as a “comb” will be small, and There is a tendency that the fineness is deteriorated and the fiber length is shortened by the crushing action. The pitch (t), which is the distance between the cutting edge and the adjacent cutting edge, is preferably set to 30 to 200 times the diameter of the conductive fiber.

As described above, it is desirable that the above-mentioned control mechanism capable of opening the conductive fibers in a continuous state and controlling the fiber length be provided adjacent to the feeding section of the conductive fibers. If the conductive fiber is too far away from the feeding section, the conductive fiber may be rubbed between the ordinary screw flight and the cylinder before reaching the control mechanism, and it may be difficult to control the fiber length and the degree of fiber opening. Also, if a normal kneading section is provided after the charging section, the conductive fibers are damaged there, which is not desirable.
Further, when a kneading section is provided after the control mechanism section, it is not desirable because the fibers are damaged unless the fiber length is particularly shortened. The continuous fiber feeding section is provided downstream of the thermoplastic resin supply port, and is fed into a molten state. If the thermoplastic resin and the conductive fiber are introduced at the same time, the fiber is cut when the resin is melted, which makes the control difficult. In addition, it is desirable to seal the input portion of the conductive fiber in a continuous state with nitrogen or the like and cut off the contact between the molten resin and the air in order to prevent the resin from being oxidized and deteriorated.

Although the extruder is not particularly limited, a multi-screw extruder such as a twin-screw extruder having a unit structure is particularly convenient. As the multi-screw extruder, the most common twin-screw extruder is preferable, and any type such as co-rotating, counter-rotating, meshing type and non-meshing type may be used. Also,
As the screw, a deep groove, a shallow groove, a single thread, a two thread, a three thread, or the like can be used. Compared with a single screw extruder, a twin screw extruder can control the resin supply amount and the screw rotation speed independently, so that the amount of conductive fiber added can be easily controlled. Further, the unit structure is advantageous in that a control mechanism for controlling the degree of opening and the fiber length can be easily provided, and the position thereof can be easily changed.

For the purpose of preventing deterioration of physical properties and poor appearance due to volatile components generated from resins and fibers and bubbles embraced by the conductive fibers, deaeration is performed after the control mechanism for controlling the degree of opening and the fiber length. It is desirable to provide a mouth.

In the present invention, it is important to provide a control mechanism having irregularities on at least a part of the surface of the screw and / or the inner wall of the cylinder after the fiber is supplied. It can be changed depending on the desired degree of control. Further, the screw having the processing and the cylinder having the processing can be used alone or in combination. FIG. a. In c, although the screw cross section illustrates an elliptical case,
A circular shape is also possible, and in particular, in the case of an intermeshing type twin screw extruder, an elliptical shape is preferable in order to maintain self-cleaning properties. Further, different processes can be used in combination. Furthermore, in order to control the fiber length, it is also possible to change the length of the control mechanism, change the diameter at both ends as needed, or use a combination of irregularities having different pitches and depths. The preferred length of the control mechanism is 0.1 to 10 times, more preferably 0.2 to 5 times the screw diameter. The present invention is not limited to these examples, but encompasses all processes that open conductive fibers into single fibers and have a function such as a “comb” according to the target fiber length. It is.

Next, a typical example for melt-kneading a conductive fiber and a thermoplastic resin in the present invention will be described with reference to the drawings. FIG. 4 is an overall sectional view of a twin-screw twin-screw extruder preferably used in the present invention.
Supply more thermoplastic resin and black carbon, and screw 18
And melts while being conveyed in the extrusion direction, and completely melts the thermoplastic resin in the kneading zone 19.
After that, the continuous conductive fiber in the roving form is supplied from the second supply port 17 so that the full flight 20
The molten resin and the fiber are sent to the tip by the screw composed of. Then, after the fiber is opened and the fiber length is controlled by the screw uneven surface forming part 21 which is a control mechanism part adjacent to the charging port, the conductive thermoplastic resin composition 23 is extruded into an arbitrary shape by the die 22 and is formed. obtain.
It is also possible to form an uneven surface forming portion 25 on the cylinder inner wall 24 corresponding to the screw uneven surface forming portion 21. It is also possible to provide two extruder supply ports before feeding the fibrous reinforcing material, and to supply the thermoplastic resin and the black carbon separately, and to simultaneously modify and modify the polymer and alloy. It is also possible to do.

The conductive thermoplastic resin of the present invention is useful as a housing material for electric equipment and the like used for the purpose of preventing static electricity and preventing electromagnetic interference, and is specifically used for televisions, VTRs, and the like.
Examples include covers such as microwave ovens, audio equipment, word processors, computers, telephones, facsimile machines, copiers, etc., and are particularly useful as electromagnetic wave shielding housings for equipment that emits a large amount of electromagnetic waves, such as computers. Also,
These molding methods are not particularly limited, and various molding methods such as injection molding, compression molding, stamping molding, and blow molding can be used.

[0036]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the present invention is limited thereto.
The evaluation method of Izod impact strength is ASTM D-25.
6 according to ASTM D-7.
Measured according to 90. The volume resistivity as an index of conductivity was measured according to ASTM D-257. The specific gravity was measured according to ASTM D792. Regarding the fluidity during molding, when the ASTM No. 1 dumbbell is injection-molded with a Toshiba Machine's IS55-EPN injection molding machine, when the injection speed is maximized, the lowest injection pressure at which the resin is completely filled is set. It was determined as the molding lower limit pressure. The lower molding pressure is a measure of the fluidity of the molten resin, and the lower the pressure, the better the fluidity and moldability. In addition, each test is 5
The samples were measured and averaged. The fiber length of the conductive fibers in the composition was 450 ° C. × 5 in an electric furnace.
The burned ash was determined by microscopic photography.

In this experiment, 74 parts by weight of nylon 6 pellets (CM1001) manufactured by Toray and brominated polystyrene ("Virocheck" 68) manufactured by Fellow were used as thermoplastic resins.
PB) Flame retardant nylon 6 containing 21 parts by weight of antimony trioxide and 5 parts by weight of antimony trioxide is used. As conductive fibers, carbon fiber manufactured by Toray ("Treca" T700SC-1200-50)
C) was used. The following were used as carbon black.

C-1: Mitsubishi Chemical # 3030 DBP oil absorption 130 ml / 100 g Average particle size 55 nm C-2: Denka Kagaku "Tenka Perak" DBP oil absorption 190 ml / 100 g Average particle diameter 42 nm C-3: Mitsubishi Chemical Ketjen Perak EC DBP oil absorption 360ml / 100g Average particle diameter 30nm Examples 1-4 As shown in Fig. 4, a co-rotating twin screw extruder with screw diameter 30mm and L / D35 having two supply ports in the extrusion direction (Japan) Using TEX30 manufactured by Steel Works, and using two screws with two screws 3.5 mm each other, five screws inclined at 45 degrees with L / D = 2 just before the second supply port. A screw element consisting of a kneading disk is provided in the reverse order, and the L / D = 1 full flight screw is provided on the discharge side of the second supply port. 1a.
(Pitch 1 mm, cutting edge angle 30 degrees, peak and valley bottom height 1.5
mm) A processed control mechanism having a neutral screw shape having an elliptical cross section of L / D = 0.75 and having a processed shape other than the above was used. In this apparatus, flame-retardant nylon 6 pellets and carbon black were supplied from a first supply port by a screw type supply apparatus so as to have a composition shown in Table 1, and extrusion was performed at a cylinder temperature of 260 ° C and a screw rotation speed of 200 rpm. went. Next, after confirming that the resin was completely melted at the second supply port, continuous carbon fibers were introduced from the supply port. The continuous carbon fiber was constantly drawn into the extruder by the rotation of the screw, sent to the extruder tip together with the molten resin, and extruded into a strand. The strand was cooled in a cooling bath and cut into a length of 5 mm to obtain pellets of a conductive thermoplastic resin composition having a carbon fiber content of 30 wt%. The pellets were dried in a vacuum at 85 ° C. for 24 hours and dried.
Injection molding was performed using an injection molding machine (TOSHIBA MACHINE IS55EPN) at a cylinder temperature of 260 ° C. and a mold temperature of 80 ° C., and physical properties and fiber length were measured. The carbon fibers in the conductive thermoplastic resin strand were spread to single fibers and uniformly dispersed. Table 1 shows the results.

Comparative Examples 1 to 4 Flame-retardant nylon 6, carbon fiber and carbon black were extruded using the same apparatus as in the Examples so that the compositions shown in Table 1 were obtained. In Comparative Examples 3 and 4, conductive thermoplastic resin compositions using carbon black having a large DBP oil absorption were obtained as conductive thermoplastic resin compositions. The pellets were dried and injection molded in the same manner as in the examples, and the physical properties and fiber length were measured.

Comparative Example 5 A crosshead die was installed at the tip of the same extruder as in Comparative Example 1, and carbon fibers were guided into the crosshead at 4 kg / h.
It was coated with a melt of flame-retardant nylon 6 (same as in Example 1) supplied from the first supply port so as to have the composition shown in Table 1. The obtained fiber reinforced thermoplastic resin strand is 5 mm.
It was cut to length, dried and injection-molded in the same manner as in Example 1, and the physical properties and fiber length were measured. Most of the carbon fibers in the composition were present as a continuous body, but had poor spreadability and existed in bundles, and were not uniformly dispersed.

[0041]

[Table 1]

The following is clear from the examples and comparative examples.

That is, the conductive thermoplastic resin composition obtained according to the present invention has a sufficient effect of reinforcing the conductive fibers and the conductive effect of the conductive fibers and the carbon black, and exhibits good characteristic values. I have. In Comparative Examples 1 and 2 containing no carbon black, good volume resistivity was not obtained, and in Comparative Example 2 in which the carbon fiber was 40 wt%, no improvement in physical properties was observed, and specific gravity was increased. In Comparative Examples 3 and 4 in which carbon black having a large DBP oil absorption was used, improvement in volume resistivity was small when 3 wt% was added.
Addition of wt% drastically lowers Izod impact strength and deteriorates fluidity. In Comparative Example 5 in which the volume specific resistance was reduced without adding carbon black by providing a crosshead die to lengthen the fibers, the volume specific resistance was small but the fluidity was poor.

[0044]

According to the present invention, it is possible to obtain a conductive thermoplastic resin composition having excellent conductivity and mechanical properties, and also having excellent fluidity during molding. Further, the above-mentioned conductive thermoplastic resin composition can be efficiently produced by the production method of the present invention.

[Brief description of the drawings]

FIG. 1a is a perspective view of a screw that has been subjected to blade-like processing, and FIG. 1b is a cut-away perspective view of a cylinder that has undergone blade-like processing. FIG. 1c is a perspective view of a screw subjected to mesh processing in the present invention, and FIG. 1d is a cutaway perspective view of a cylinder subjected to mesh processing.

FIG. 2 is a conceptual diagram in which a cross section of a side surface of an edge portion of a screw or a cylinder which has been subjected to the edge processing shown in FIG. 1a or 1b is enlarged.

FIG. 3a is a side view of a screw obtained by performing a blade-like processing on a flight of a full-flight screw in order.
b is a side view of a screw in which mesh processing has been performed on the flight of the full flight screw in order.

FIG. 4 shows two supply ports preferably used in the present invention.
FIG. 2 is an overall cross-sectional view of the extruder provided with the above.

[Explanation of symbols]

 θ. Edge angle t. Pitch h. Height of summit and valley bottom Screw with blade-like processing part 2. Screw edge processing part 3. 3. Cylinder having an edge-shaped part 4. Edge processing part of cylinder inner wall Screw with mesh processing part 6. 6. Screw mesh processing part 7. Cylinder with reticulated part 8. Reticulated portion of cylinder inner wall 9. Full-flight screw in the order of having a blade-shaped processing part 10. Screw edge processing part 11. Full-flight screw with net-like processing part 12. Screw mesh processing part Screw full flight section 14. Flight surface 15. Cylinder inner wall 16. First supply port 17. Second supply port 18. Screw 19. Kneading zone 20. Forward flight full flight 21. Screw uneven surface forming part 22. Dice 23. Fiber reinforced thermoplastic resin composition 24. Cylinder inner wall 25. Cylinder inner wall uneven surface forming part

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI H01B 1/24 H01B 1/24 Z

Claims (8)

[Claims] 1. A conductive thermoplastic resin composition obtained by compounding a conductive resin and black carbon with a thermoplastic resin, and dibutyl phthalate (DBP) oil absorption of the black carbon to be compounded by JIS K6221A method. 250
A conductive thermoplastic resin composition having a content of not more than 100 ml / 100 g. 2. The conductive thermoplastic resin composition according to claim 1, wherein the conductive fibers are carbon fibers. 3. The conductive thermoplastic resin composition has a weight of 5 to 45 watts.
3. The conductive thermoplastic resin composition according to claim 1, comprising t% of conductive fibers and 0.5 to 20% by weight of black carbon. 4. The conductive thermoplastic resin composition according to claim 1, wherein black carbon having an average particle diameter of 31 nm or more is used. 5. The conductive thermoplastic resin composition according to claim 1, wherein the black carbon is at least one selected from carbon black and graphite. 6. The relationship (Lw / d) between the weight average fiber length (Lw) and the fiber diameter (d) of the conductive fibers in the composition is 2
The ratio of the weight average fiber length (Lw) to the number average fiber length (Ln) is from 1.1 to 500, and the ratio is from 1.1 to 500.
The conductive thermoplastic resin composition according to any one of the above. 7. A housing material for electric / electronic equipment comprising the conductive thermoplastic resin composition according to claim 1. 8. An extruder provided with a fiber opening / fiber length control mechanism in which at least a part of a screw and / or a cylinder is surface-deformed, is used to melt a thermoplastic resin and to continuously melt the thermoplastic resin in the molten resin. The conductive fiber in a state is supplied, and the conductive fiber is spread and cut while passing through the opening / fiber length control mechanism, dispersed in a resin, and discharged from an extruder. A method for producing a conductive thermoplastic resin composition, comprising producing the conductive thermoplastic resin composition according to any one of the above.