JP3298987B2 - Manufacturing method of conductive resin masterbatch - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conductive resin masterbatch containing a large amount of conductive carbon black, and particularly to a surface smoothness excellent in a conductive resin product finally produced by adding the masterbatch. And a conductive thermoplastic resin product produced by adding the master batch.

[0002]

2. Description of the Related Art A conductive resin is a computer, a VT.
In recent years, demand has been remarkably growing mainly for applications such as antistatic and electromagnetic wave shielding of home electric appliances and the like. Conventionally,
As a method of imparting conductivity to a thermoplastic resin, there is known a method of filling carbon black (JP-A-60-65064 and JP-A-55-31103). In addition, the carbon black partially scatters and deteriorates the working environment. In addition, the heat generated by shearing of the carbon black causes a decrease in the molecular weight of the resin, resulting in a problem that the resin strength is reduced. The conductive thermoplastic resin containing carbon black is formed into various shapes depending on the application.
When formed into a film of less than mm, protrusions due to carbon black undispersed material appear on the surface, not only impairing the aesthetic appearance, but also using this as a transfer roll of a copying machine, the image becomes unclear. Problems have been pointed out. Among these problems, a method using a carbon black-rich resin masterbatch has been proposed for the purpose of preventing the carbon black from scattering.
-58747). After adding a thermoplastic resin dissolved in an organic solvent to an aqueous solution in which carbon black is dispersed,
Because it is obtained by removing water and organic solvents,
Applicable to all thermoplastic resins, compared to the conventional method of manufacturing by kneading the thermoplastic resin and carbon black at or above the melting temperature of the resin, the resin that can be used is limited due to the solubility of the resin in the organic solvent In addition, the method requires a step of removing water and an organic solvent, and thus is not practical. On the other hand, even if the conductive carbon black is kneaded into the desired resin using a Banbury mixer or the like to produce a high-concentration masterbatch, the conductive carbon black is extremely difficult to knead, and the masterbatch produced in this manner is used. When a final conductive resin product is manufactured by using the method, there is a problem that the surface smoothness of the obtained product is impaired. Particularly, when the masterbatch resin is a high-performance resin other than the polyolefin resin, the problem is serious.

[0003]

SUMMARY OF THE INVENTION The present invention can improve the surface smoothness of a final conductive resin product produced by adding and adding conductive carbon black at a high concentration. To provide a conductive carbon black masterbatch for high-performance resins. Another object of the present invention is to provide a highly functional conductive resin product manufactured by adding the master batch.

[0004]

The present invention has been made based on the finding that the above problems can be effectively solved by combining a specific carbon black with a resin having a specific melt flow characteristic. . That is, the present invention
(A) a thermoplastic resin other than a polyolefin resin and (b)
The conductive carbon black is an essential component, and the thermoplastic resin of the component (a) has a melt flow rate (MFR) of 6 g / 10 min or more, and the DBP oil absorption of the conductive carbon black is 300 ml / 100 g or more.
ml / 100 g, and the content of the conductive carbon black is 15 to 40 parts by weight based on 100 parts by weight of the total amount of the components (a) and (b), and the volume specific resistance is
Provided is a conductive resin masterbatch characterized by being 0.1 Ω · cm or more and less than 10 Ω · cm.

[0005] The resin used in the conductive resin masterbatch of the present invention has strength and heat resistance in accordance with the use of the conductive thermoplastic resin obtained by using the masterbatch, and is 6 g / 10 min or more. Preferably 8g / 10min
~ 2000 g / 10 min, particularly preferably 8 g / 10 min
It is a high-performance thermoplastic resin having a melt flow rate (MFR) of min to 600 g / 10 min. Specifically, styrene resins such as polystyrene resin, ABS resin, and AS resin; polyester resins such as polyethylene terephthalate resin and polybutylene terephthalate resin;
6-nylon resin, polyamide resin such as 6,6-nylon resin; polysulfone resin, modified polysulfone resin, polyallyl sulfone resin, polyketone resin, polyetherimide resin, polyarylate resin, polyphenylene sulfide resin, liquid crystal polymer, polyether Super engineering resins such as sulfone resins; polyether ether ketone resins, polyimide resins, polyamide imide resins, and fluororesins; polyvinyl chloride resins, thermoplastic urethane resins, polyacetal resins, polycarbonate resins, modified polyphenylene ether resins, and the like. Among them, polycarbonate resin, polyethylene terephthalate resin, polybutylene terephthalate resin,
6-nylon resin, 6,6-nylon resin, polystyrene resin, polyphenylene sulfide resin, thermoplastic urethane resin, modified polyphenylene ether resin are preferred, and particularly preferred are polycarbonate resin, polyethylene terephthalate resin, polybutylene terephthalate resin, and polystyrene resin. , Polyphenylene sulfide resin, thermoplastic urethane resin, and modified polyphenylene ether resin. Here, the melt flow rate (MF
R) is measured according to the measurement method for the resin for which the method for measuring the melt flow rate of each resin is specified in the Japanese Industrial Standards, and the resin not specified is measured using an apparatus described in JIS K7210A method. It is a value measured at the temperature and load shown in the table. The following table shows the measurement conditions.

[0006]

[Table 1] Melt flow rate measurement conditions for resin ───────────────────────────────────Resin standard Temperature (° C) Load (Kgf) Polystyrene resin JIS K6871 200 5.00 Other than polystyrene resin JIS K6874 220 10.00 Styrene resin Polyester resin-275 2.16 6-nylon resin JIS K7210 230 2.16 6 Other than 6-nylon resin JISK7210 275 2.16 Polyamide resin Super engineering resin-316 5.00 Polyvinyl chloride resin-190 10.00 Thermoplastic urethane resin JISK7311 230 10.00 Polyacetal resin JISK7210 190 2.16 Polycarbonate resin JISK7210 300 1.20 Modified polyphenylene ether Resin-2 50 10.00 Other resins-230 10.00

The conductive carbon black used as the component (b) in the present invention has a DBP oil absorption of 300 ml / 10.
The amount is from 0 g to less than 400 ml / 100 g, preferably from 340 ml / 100 g to less than 400 ml / 100 g. The conductive masterbatch of the present invention has a volume resistivity of 0.1 Ω · cm or more and less than 10 Ω · cm, and has a conductivity of 100 parts by weight based on the total amount of the thermoplastic resin other than the polyolefin resin and the conductive carbon black. 15 to 40 parts by weight, preferably 15 to 30 parts by weight of the carbon black. In the present invention, the conductive carbon black,
Only by employing a specific resin and a specific compounding amount, the surface smoothness of the final conductive resin product produced by adding and adding the conductive carbon black, which is the object of the present invention, at a high concentration It has been possible to provide a conductive carbon black masterbatch for a high-performance resin, which is capable of improving the performance. The masterbatch of the present invention includes mica, glass fiber, silica, talc in order to improve the heat resistance, dimensional stability, rigidity, and mechanical strength of the conductive thermoplastic resin obtained using this masterbatch. Inorganic fillers such as calcium carbonate, zinc oxide, barium sulfate, stainless steel, copper oxide, nickel, nickel oxide and zirconia silicate can also be blended. These inorganic fillers, based on the total amount of 100 parts by weight of the thermoplastic resin and the conductive carbon black,
It is desirable to use it in a proportion of 5 to 300 parts by weight. Also,
For the purpose of improving the moldability and preventing deterioration during kneading of the thermoplastic resin and the conductive carbon black, a known phenol type,
Known flame retardants and plasticizers can be used depending on the molding aids and applications, such as phosphorus-based antioxidants, metal soaps, lubricants such as fatty acid amide derivatives, and the like.

The conductive masterbatch of the present invention is obtained by kneading conductive carbon black and a thermoplastic resin other than a polyolefin resin at a temperature not lower than the melting temperature of the resin, cooling, and then forming into an appropriate shape such as a pellet, a powder, or a lump. It is manufactured by molding. As a kneading device, a single-screw extruder, a twin-screw extruder, a two-roll mill, a Banbury mixer, an intermix,
A known device such as a pressure kneader can be used. The conductive masterbatch of the present invention is used as a raw material when producing a conductive thermoplastic resin, and the masterbatch is used as a diluent resin or a known inorganic filler depending on the application, an antioxidant, a lubricant, a flame retardant. By mixing with a plasticizer, a conductive thermoplastic resin is produced. The amount of the masterbatch of the present invention is usually 10 to 80 parts by weight, preferably 15 to 70 parts by weight, based on 100 parts by weight of the conductive thermoplastic resin.
Parts by weight. If the amount is less than 10 parts by weight, it becomes difficult to impart conductivity to the thermoplastic resin obtained by using the master batch of the present invention, while if the amount is more than 80 parts by weight, the strength of the obtained conductive thermoplastic resin is reduced. There is a tendency to decrease.

A known method is used for mixing the conductive masterbatch and the diluent resin to obtain a conductive thermoplastic resin. For example, a method of dry-blending the masterbatch and the diluted resin with a mixer such as a Henschel mixer or a tumbler, a method of kneading with the above-described kneading apparatus, and the like can be mentioned. In addition, by molding this mixture by a known molding method such as injection molding, vacuum molding, blow molding, inflation molding, etc., a conductive thermoplastic resin having a shape corresponding to the use such as a sheet shape, a film shape, a plate shape, and a different shape is used. The product is obtained. Thus, the obtained conductive thermoplastic resin has a volume resistivity of 10 ⁰
It has conductivity of ~ 10 ¹⁵ Ω · cm and is excellent in both strength and surface smoothness, so it is suitable for packaging materials for electronic devices, ICs, etc., tray carriers, surface heating elements, surface switches, electrodes, electromagnetic wave shielding materials. It can be used in a wide range of fields such as applications.

[0010]

Industrial Applicability According to the present invention, a high-performance resin containing a conductive carbon black at a high concentration and having excellent surface smoothness of a final conductive resin product produced by adding the conductive carbon black can be obtained. A conductive carbon black masterbatch is provided. In addition, by using the conductive masterbatch of the present invention, when producing a conductive thermoplastic resin, there is no deterioration of the working environment due to scattering of carbon, and a small amount of conductive masterbatch can provide a good conductive property. A conductive thermoplastic resin product having excellent properties and excellent resin strength can be obtained. Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

[0011]

【Example】

Example 1 A predetermined amount of carbon black and a thermoplastic resin were kneaded using a twin-screw extruder at a cylinder temperature of 220 to 350 ° C, and after cooling, a columnar conductive masterbatch was obtained using a pelletizer. This master batch is 220-35
By pressing at 0 ° C, 10cm × 10cm × 0.2c
m was prepared for physical property evaluation, and then the volume resistivity value of the physical property evaluation sample was measured. Tables 1 and 2 show the composition, volume resistivity and moldability of the masterbatch.

The following were used as carbon black and resin. Carbon black A: carbon black with DBP oil absorption of 395 ml / 100 g Carbon black B: carbon black with DBP oil absorption of 370 ml / 100 g Carbon black C: carbon black with DBP oil absorption of 210 ml / 100 g Polycarbonate resin A: Toughlon A-2200 (Idemitsu Petroleum) (MFR: 12 g / 10 min, Measurement conditions: 300 ° C.)
1.2 kg) Polycarbonate resin B: Toughlon A-3000 (manufactured by Idemitsu Petrochemical) (MFR: 3 g / 10 min, measurement conditions: 300 ° C., 1.
2Kg) Polybutylene terephthalate resin: Toray PBT1401
X04 (manufactured by Toray) (MFR: 18 g / 10 min, measurement conditions: 275 ° C,
2.16Kg) Polyethylene terephthalate resin: Viropet EMC
307X04 (manufactured by Toyobo) (MFR: 120 g / 10 min, measurement condition: 275)
6 ° C., 2.16 Kg) 6-nylon resin: Novamide 1020 (manufactured by Mitsubishi Kasei) (MFR: 10 g / 10 min, measurement conditions: 230 ° C.)
2.16Kg) 6,6-nylon resin: Torayamiran CM3001-N
(Manufactured by Toray) (MFR: 70 g / 10 min, measurement conditions: 275 ° C.,
2.16 Kg) Polystyrene resin A: Idemitsu Styrol IT-41 (manufactured by Idemitsu Petrochemical) (MFR: 22 g / 10 min, measurement conditions: 200 ° C,
5.00 Kg) Polystyrene resin B: Idemitsu Styrol ET-60 (manufactured by Idemitsu Petrochemical) (MFR: 2 g / 10 min, measurement conditions: 200 ° C, 5.
00Kg) Polyphenylene sulfide resin: M-2888 (manufactured by Toray Philippe Petroleum) (MFR: 600 g / 10 min, measurement conditions: 316)
Modified polyphenylene ether resin: Noryl 115 (manufactured by Nippon GE Plastics) (MFR: 10 g / 10 min, measurement conditions: 250 ° C,
10.00 kg) Thermoplastic polyurethane resin: Elastolane C85A11
FG (Takeda Bird Urethane Industry) (MFR: 70 g / 10 min, measurement conditions: 230 ° C.,
Glass fiber: CS03MA416 (manufactured by Asahi Fiberglass) Zinc oxide: Zinc flower No. 3 (manufactured by Hakusui Chemical Co., Ltd.) The moldability is as follows. The composition which was difficult to produce a masterbatch due to difficulty was evaluated as x. In addition, the volume specific resistance was measured according to the Japan Rubber Association SRIS-2301.

[0013]

[Table 2] Table 1 ──────────────────────────────────── Example of implementation No. AB C DEF GHI II Composition (parts by weight) Carbon black A 0 0 0 20 0 0 0 0 0 Carbon black B 20 20 20 0 17 17 20 30 20 Carbon black C 0 0 0 0 0 0 0 0 0 Polycarbonate 80 0 0 0 0 0 0 0 0 Resin A Polybutylene tele 0 0 80 0 0 0 0 0 0 Phthalate resin Polyethylene tele 0 0 0 80 0 0 0 0 0 Phthalate resin 6-Nylon resin 0 0 0 0 0 83 0 0 0 6,6-Nylon resin 0 0 0 0 83 0 0 0 0 Polyphenylene 0 80 0 0 0 0 0 0 0 Sulfide resin Polystyrene resin A 0 0 0 0 0 0 80 0 0 Thermoplastic polyurethane 0 0 0 0 0 0 0 70 0 Thermoplastic resin Modified polyphenylene 0 0 0 0 0 0 0 0 80 Ether resin ────────成形 Formability ○ ○ ○ ○ ○ ○ ○ ○ ○ ────────────固有 Specific volume resistance 8.0 8.3 1.2 1.0 4.6 4.1 1.4 8.0 1.2 (Ωcm) × 10 ^-1 × 10 ^-1 × 10 ⁰ × 10 ⁰ × 10 ⁰ × 10 ⁰ × 10 ⁰ × 10 ^-1 × 10 ⁰ ──────────────────────────── ────────

[0014]

[Table 3] Table-2 {Comparative example, etc. (parts by weight) JKLMN} ──────────────────────────── Carbon black A 50 0 0 0 0 Carbon black B 0 6 0 20 20 Carbon black C 0 0 20 0 0 Polycarbonate 50 94 80 0 0 Resin A Polycarbonate 0 0 0 80 0 Resin B Polystyrene resin B 0 0 0 0 80 ────────────────────────成形 Formability × ○ ○ ○ ○ ───────────────────────────── Volume resistivity 2.3 3.8 3.2 4.8 （ Ω · cm) − × 10 ³ × 10 ⁴ × 10 ⁰ × 10 ⁰ ─────────────────────────────

Example 2 The masterbatch, inorganic filler and thermoplastic resin described in Example 1 were used in a twin-screw extruder at a cylinder temperature of 220.
After kneading at ~ 350 ° C and cooling, columnar pellets were obtained using a pelletizer. For comparison, a predetermined amount of carbon black, an inorganic filler and a thermoplastic resin were kneaded at a cylinder temperature of 220 to 350 ° C. using a twin-screw extruder without using a masterbatch, and after cooling, a pelletizer was used. Was used to obtain a columnar pellet. The pellets were put into an injection molding machine, and injection-molded at a cylinder temperature of 220 to 350 ° C. using a predetermined mold to obtain a 7.5 cm × 7.5 cm × 0.3 cm sample for evaluating physical properties. Surface smoothness of physical property evaluation sample,
Izod impact strength and volume resistivity were measured.
Tables 3 and 4 show the compositions and measurement results. The surface smoothness of the sample for evaluating physical properties was evaluated as x when the surface of the sample was dull, and as ○ when glossy, and the Izod impact strength and the volume resistivity were measured according to JIS.
It was measured according to K-7110 and Japan Rubber Association SRIS-2301.

[0016]

[Table 4] Table 3 ────────────────────────────────── Example No. 1 2 3 4 5 6 7 8 Composition (parts by weight) Example 1 A Composition 35 60 00 00 00 00 B Composition 0 0 60 00 00 00 0 C Composition 0 0 0 36 0 00 00 D Composition 0 0 0 0 60 0 0 0 E composition 0 0 0 0 0 60 0 0 G composition 0 0 0 0 0 0 30 0 I composition 0 0 0 0 0 0 0 40 Polycarbonate 65 40 0 0 0 0 0 0 Resin A Polybutylene tele 0 0 0 65 0 0 0 0 Phthalate resin Polyethylene tele 0 0 0 0 40 0 0 0 Phthalate resin 6, 6-Nylon resin 0 0 0 0 0 40 0 0 Polyphenylene 0 0 40 0 0 0 0 0 Sulfide Resin Polystyrene resin A 0 0 0 0 0 0 70 0 Modified polyphenylene 0 0 0 0 0 0 0 60 Ether resin Zinc oxide 0 80 0 0 0 0 0 0 Glass fiber 0 0 80 0 60 60 0 0 Izod impact 8.5 4.3 5.4 4.6 6.2 5.9 5.2 6.0 strength (kgfcm / cm ²⁾ (with 1/8 inch notched) surface Lubricity ○ ○ ○ ○ ○ ○ ○ ○ ──────────────────────────────────── Volume resistivity 1.9 7.3 4.9 4.2 8.3 6.3 2.8 3.2 (Ωcm) × 10 ⁵ × 10 ³ × 10 ⁵ × 10 ⁶ × 10 ³ × 10 ⁵ × 10 ⁶ × 10 ⁵

[0017]

[Table 5] Table-4 ──────────────────────────────────── Comparative Example No. 9 10 11 12 13 14 15 16 Composition (parts by weight) Example-1 K composition 0 0 0 0 35 0 0 0 L composition 0 0 0 0 0 70 0 0 M composition 0 0 0 0 0 0 35 0 N composition Object 0 0 0 0 0 0 0 30 Carbon black A 0 0 12 0 0 0 0 0 Carbon black B 7 7 0 10.2 0 0 0 0 Polycarbonate 93 0 0 0 65 30 65 0 Resin A Polystyrene resin A 0 0 0 0 0 0 0 70 Polybutylene tele 0 98 0 0 0 0 0 0 Phthalate resin Polyethylene tele 0 0 88 0 0 0 0 0 Phthalate resin 6, 6-Nylon resin 0 0 0 89.8 0 0 0 0 Glass fiber 0 0 60 60 0 0 0 0 Izod impact 2.1 0.5 1.6 0.6 8.9 2.9 9.0 5.1 Strength (kgfcm / cm ² ) (with 1/8 inch notch) Surface smoothness × × × × ○ ○ × × ────────────固有 Volume specific Resistance value 3.3 6.3 9.9 9.0 10 ¹⁶ 10 ¹⁶ 3.5 5.7 (Ωcm) × 10 ⁵ × 10 ⁶ × 10 ³ × 10 ⁵ or more × 10 ⁹ × 10 ¹⁰

From Tables 3 and 4, No1 and No9, No4 and No1
0, No5 and No11, and No6 and No12 have the same composition and are data comparing the case where the masterbatch of the present invention is used and the case where the masterbatch is not used. In comparison with the case where no is used, the result that the volume resistivity value of the obtained conductive resin was good and the Izod impact strength was 4 to 10 times better was obtained. No. 14 is a comparative example in which a masterbatch blended with carbon black other than the present invention was used. However, even if the masterbatch of the present invention was used twice (70 parts by weight) to obtain a conductive resin. The volume specific resistance value is 10 ¹⁶ Ω · cm or more, and no conductivity can be provided (comparison between No. 1 and No. 14). No15, No
16 is a polycarbonate resin other than the present invention (MFR = 3 g / 10 min) and a polystyrene resin (M
FR = 2 g / 10 min) is a comparative example in which a masterbatch blended with a polycarbonate resin or a polystyrene resin of the present invention was used. In this case, the conductivity shows a bad value of about 10 ⁴ Ω · cm in volume resistivity.

Example 3 Pellets obtained by the same method as described in Example 2 were put into an inflation molding machine, and a film having a thickness of 60 μm was produced at a cylinder temperature of 220 to 300 ° C. The surface resistivity and the film strength were measured. The surface smoothness was evaluated by a surface roughness meter as ○ when the surface unevenness was less than 5 μm, and as X when more than 5 μm. The film strength was evaluated as ○ when the film was bent ten times and not cut from the fold, and as X when cut. The surface specific resistance value is ASTM D-
257 was measured. Table 5 shows the composition and measurement results.
Shown in

[0020]

[Table 6] Table 5 ──────────────────────────────────── Example Comparison Example No 17 18 19 20 21 22 23 24 25 26 ──────────────────────────────────── Composition (weight Part) Example-1 A composition 45 0 0 0 0 0 0 0 0 0 0 D composition 0 55 0 0 0 0 0 0 0 0 0 F composition 0 0 55 0 0 0 0 0 0 0 0 H composition 0 0 0 50 0 0 0 0 0 0 0 L composition 0 0 0 0 0 0 0 0 70 0 M composition 0 0 0 0 0 0 0 0 0 45 Carbon 0 0 0 0 0 11 0 0 0 0 Black A Carbon 0 0 0 0 9 0 9.35 15 0 0 Black B polycarbonate 55 0 0 0 91 0 0 0 30 55 Polyester resin B polyethylene 0 45 0 0 0 89 0 0 0 0 Terephthalate resin 6-nylon 0 0 45 0 0 0 90.65 0 0 0 Resin Thermoplastic urethane resin 0 0 0 50 0 0 0 85 0 0 ───────────────────────────────── ─── Phil Strength ○ ○ ○ ○ × × × × × ○ ──────────────────────────────────── Surface smoothness ○ ○ ○ ○ × × × × ○ × 固有 Surface specific 1.3 2.9 1.9 1.9 2.6 4.0 4.2 4.2 10 ¹⁶ 3.8 Resistance (Ω) × 10 ⁶ × 10 ⁷ × 10 ⁷ × 10 ⁴ × 10 ⁶ × 10 ⁷ × 10 ⁷ × 10 ⁴ or more × 10 ¹⁰ ──────── ────────────────────────────

According to Table-5, No. 17 and No. 21, No. 18 and No.
22, No19 and No23, No20 and No24 have the same composition, and are data comparing the case where the masterbatch of the present invention was used and the case where the masterbatch was not used. As compared with the case where no was used, the result that the strength, surface smoothness and surface resistivity of the obtained conductive film were good was obtained. No. 25 is a comparative example in which a masterbatch blended with carbon black other than the present invention was used. In order to obtain a conductive resin, 1.4 times (70 parts by weight) of the masterbatch of the present invention was used. However, the surface resistivity is 10 ¹⁶ Ω
cm or more, and conductivity cannot be imparted. (No
No. 26 is a comparative example using a masterbatch blended with a polycarbonate resin other than the present invention, but an example using a master patch blended with the polycarbonate resin of the present invention. Compared with (No. 17), the surface smoothness is poor, and the conductivity shows a surface resistivity of about 10 ⁴ Ω which is poor.

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Hideo Komatsu 1-3-7 Honjo, Sumida-ku, Tokyo Inside Rion Co., Ltd. (56) References JP-A-61-209238 (JP, A) JP-A Sho 62-20533 (JP, A) JP-A-62-146938 (JP, A) JP-A-6-345951 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) C08L 1/00 -101/16 C08K 3/00-13/08 C08J 3/20-3/22

Claims (1)

(57) [Claims] 1. A thermoplastic resin other than a polyolefin resin, having a melt flow rate (MFR) of 6 g.
/ 10 min or more of a thermoplastic resin, and (b) DBP
Oil absorption of 300ml / 100g or more and 400ml / 100
g of conductive carbon black in an amount of 15 to 40 parts by weight based on 100 parts by weight of the total of components (a) and (b) at a temperature not lower than the melting temperature of the resin and cooling. The volume resistivity is 0.1Ω · cm or more and 10Ω
-A method for producing a conductive resin master batch having a size of less than cm.