JP6035201B2 - Conductive resin composition - Google Patents

Description

  The present invention relates to a conductive resin composition.

  In various fields such as electrode materials, automotive conductive materials, and semiconductor packages, conductive resin compositions in which carbon black is blended with a thermoplastic resin, which is an electrical insulator, are widely used. . In order to obtain a conductive article having excellent conductivity by the conductive resin composition, the conductivity of carbon black is important.

As carbon black which has the outstanding electroconductivity, what is shown below is known, for example.
(I) a liquid hydrocarbon (feedstock), by partial oxidation reaction in the presence of molecular oxygen and water vapor in a furnace to obtain at the same time producing synthesis gas, DBP oil absorption amount of 290~640cm ³ / 100g carbon Black (for example, Patent Documents 1 to 4).
(Ii) liquid hydrocarbons (feedstock), by partial oxidation reaction in the presence of molecular oxygen and water vapor in a furnace to obtain at the same time producing synthesis gas, with a DBP oil absorption 400 cm ^3/100 g or more, and Carbon black having a specific surface area of 1000 m ² / g or more (for example, Patent Document 5).

However, carbon black having a high DBP oil absorption amount as described above and having an excellent conductivity imparting effect is poor in dispersibility, so that the surface smoothness of the conductive article tends to be lowered.
On the other hand, as carbon black, those having excellent dispersibility such as acetylene black are known. However, when acetylene black or the like is used, the conductivity imparting effect is low, and it is difficult to obtain high mechanical strength.

Japanese Patent Laid-Open No. 60-60912 JP 60-67564 A JP 60-88073 A Japanese Patent Application Laid-Open No. 60-15269 JP-A-60-197763

  The present invention provides a conductive resin composition capable of producing a conductive article having high mechanical strength and excellent surface smoothness and conductivity.

The conductive resin composition of the present invention contains carbon black satisfying the following conditions (1) to (3) and a resin.
(1) A BET specific surface area is 350 to 650 m ² / g.
(2) DBP oil absorption is 270-340 cm < ³ > / 100g.
(3) The ratio D ₉₀ / D _mod of the D90 diameter (D ₉₀ ) to the mode diameter (D _mod ) measured by the method for measuring an aggregate diameter described in JIS K6217-6 is 1.90 to 2.20. is there.

  By using the conductive resin composition of the present invention, a conductive article having both high mechanical strength and excellent surface smoothness and conductivity can be produced.

It is a graph for explaining how to determine the mode diameter _{(D mod)} and D90 diameter _{(D 90).}

  The conductive resin composition of the present invention contains carbon black and a resin. Moreover, the conductive resin composition of this invention may contain components other than carbon black and resin as needed.

[Carbon black]
Carbon black satisfies the following conditions (1) to (3). Carbon black satisfying the following conditions (1) to (3) has both good dispersibility and conductivity imparting effects. Therefore, by using the carbon black, a conductive resin composition capable of producing a conductive article having both high mechanical strength and excellent surface smoothness and conductivity is obtained.
(1) A BET specific surface area is 350 to 650 m ² / g.
(2) DBP oil absorption is 270-340 cm < ³ > / 100g.
(3) The ratio D ₉₀ / D _mod of the D90 diameter (D ₉₀ ) to the mode diameter (D _mod ) measured by the method for measuring an aggregate diameter described in JIS K6217-6 is 1.90 to 2.20. is there.

BET specific surface area of the carbon black is 350~650m ² / g, preferably from ^{350~550m 2 / g, 350~500m 2 /} g is more preferable. If the BET specific surface area of carbon black is not less than the lower limit, the conductive resin composition has good conductivity, and a conductive article having excellent conductivity can be produced. In addition, a conductive article having high mechanical strength can be manufactured. If the BET specific surface area of carbon black is less than or equal to the upper limit, the dispersibility of carbon black in the resin will be good, and a conductive article having excellent surface smoothness can be produced.
The BET specific surface area of carbon black is measured by a method based on ASTM D 3037.

Carbon black is a powder composed of secondary particles composed of a chain of primary particles connected in a kitchen shape. Since DBP (n-dibutyl phthalate) is absorbed into the voids of the kitchen chain, the DBP oil absorption is an important index value of carbon black.
DBP oil absorption of carbon black is 270~340cm ³ / 100g, preferably ^{270~320cm 3 / 100g, 285~315cm 3 /} 100g and more preferably. If the DBP oil absorption of carbon black is equal to or greater than the lower limit, carbon black can efficiently form a network in the resin, and a conductive article having excellent conductivity can be produced. If the DBP oil absorption amount of carbon black is not more than the upper limit value, the dispersibility in the resin is good and a conductive article having excellent surface smoothness can be produced.
Note that the DBP oil absorption of carbon black is a value measured with a sample amount of 9 g under conditions based on ASTM D 2414.

Carbon black has a ratio D ₉₀ / D _mod of 1.90 to 2.20 of a D90 diameter (D ₉₀ ) to a mode diameter (D _mod ) measured by an aggregate diameter measuring method described in JIS K6217-6. It is.
The D90 diameter (D ₉₀ ) means a particle diameter at a point of 90% in a cumulative volume distribution curve with the total volume distribution determined on a volume basis being 100%, that is, a volume-based cumulative 90% diameter. . The mode diameter (D _mod ) means the particle diameter having the largest appearance ratio in the particle size distribution, that is, the particle diameter at the maximum value of the distribution.
The ratio D ₉₀ / D _mod is an index representing the spread of the particle size distribution. When the ratio D ₉₀ / D _mod is large, that is, when the particle size distribution is broad, good dispersion performance is easily obtained upon addition to a resin or the like, but the conductivity imparting effect is reduced. Therefore, control of the ratio D ₉₀ / D _mod is important in order to achieve both conductive performance and dispersion performance.

The ratio D ₉₀ / D _mod is 1.90 to 2.20, preferably 2.00 to 2.20, and more preferably 2.10 to 2.20. When the ratio D ₉₀ / D _mod is equal to or higher than the lower limit value, a conductive resin composition having excellent dispersibility can be obtained. When the ratio D ₉₀ / D _mod is not more than the upper limit value, a conductive resin composition having excellent conductivity can be obtained. Moreover, the conductive resin composition which has high mechanical strength in addition to a dispersibility and electroconductivity is obtained by setting it as said range.

The D _mod of carbon black is preferably 0.110 to 0.140 μm, and more preferably 0.115 to 0.135 μm. If D _mod is within the above range, a conductive resin composition excellent in conductivity and surface smoothness can be easily obtained.
Carbon black D ₉₀ is preferably 0.230 to 0.300 μm, more preferably 0.250 to 0.290 μm. When _D90 is within the above range, a conductive resin composition excellent in conductivity and surface smoothness can be easily obtained.

The carbon black, from the viewpoint of easy good dispersibility and conductivity are compatible, the BET specific surface area of 350~550m ² / g, DBP oil absorption amount 270~320cm ³ / 100g, the ratio _D 90 _{/ D mod} is Carbon black that is 1.90 to 2.20 is particularly preferred.

30-55 nm is preferable and, as for the average primary particle diameter of carbon black, 35-50 nm is more preferable. If the average primary particle diameter of the carbon black is not less than the lower limit value, the dispersibility becomes better. If the average primary particle diameter of carbon black is not more than the upper limit value, a good conductive resin composition can be easily obtained.
In addition, the average primary particle diameter of carbon black is a value measured by the method described in Examples.

The volatile content of carbon black is preferably 0.8% by mass or less, and more preferably 0.5% by mass or less. If the volatile content of carbon black is less than or equal to the upper limit value, good conductivity can be easily obtained.
In addition, the volatile matter of carbon black is measured by the method as described in an Example.

The ash content of carbon black is preferably 0.05% by mass or less, and more preferably 0.03% by mass or less. If the ash content of the carbon black is less than or equal to the upper limit value, it is easy to suppress a decrease in the strength of the resin and to obtain stable conductivity.
The ash content of carbon black is measured by a method based on ASTM D 1506.

24M4DBP oil absorption of the carbon black of the present invention (compression oil absorption amount of compressed four times the carbon black in 165 MPa) is preferably from ^{130~200cm 3 / 100g, 140~180cm 3 /} 100g and more preferably. If the 24M4DBP oil absorption is greater than or equal to the lower limit, stable conductive performance can be easily obtained at the time of addition. If the 24M4DBP oil absorption is less than or equal to the upper limit value, good dispersibility is easily obtained at the time of addition.
The 24M4DBP oil absorption is measured using a sample amount of 20 g under the conditions described in JIS K 6217-4.

Carbon black preferably has an iodine adsorption amount of 420 to 660 mg / g and a 1% by mass aqueous solution having a pH of 9 to 11. Thereby, the conductive resin composition excellent in electroconductivity and surface smoothness is easy to be obtained.
The iodine adsorption amount is measured by the method described in JIS K 6217-1.

The ratio of CTAB (cetyltrimethylammonium bromide) adsorption specific surface area to CET specific surface area in carbon black (CTAB / BET) is preferably 0.3 to 0.8, more preferably 0.6 to 0.8. When the ratio (CTAB / BET) is within the above range, a conductive resin composition excellent in conductivity and surface smoothness can be easily obtained.
The CTAB adsorption specific surface area is measured under the conditions described in JIS K 6217-3.

  0.5-40 mass% is preferable and, as for the ratio of the carbon black in the conductive resin composition (100 mass%) of this invention, 3.0-30 mass% is more preferable. If the ratio of the carbon black is equal to or higher than the lower limit, a conductive resin composition having excellent conductivity can be easily obtained. If the ratio of the carbon black is less than or equal to the upper limit value, a decrease in strength of the conductive resin composition is likely to be suppressed.

(Method for producing carbon black)
An oil furnace method is mentioned as a manufacturing method of carbon black.
Specific examples of the oil furnace method include, for example, a method in which raw oil is partially oxidized in the presence of molecular oxygen and water vapor in a furnace to generate synthesis gas and simultaneously produce carbon black. .
Examples of the carbon production furnace include an LG furnace and an SG furnace, and an SG furnace is particularly preferable.

  The conditions for obtaining carbon black satisfying the above conditions (1) to (3) are the ratio of steam supplied to the furnace per ton of feedstock (steam ratio), and the feed to the furnace per ton of feedstock. It is important to control all the production conditions corresponding to the four items of the ratio of molecular oxygen (oxygen ratio), the amount of feedstock supplied into the furnace per unit time, and the fact that the feedstock is not emulsified. In particular, in order to satisfy the condition (3), it is particularly important to control the supply amount of the raw material oil and the suppression of the emulsification of the raw material oil.

  The steam ratio is preferably 200 to 450 kg / t, more preferably 250 to 300 kg / t per ton of feedstock. If the steam ratio is within the above range, carbon black satisfying the conditions (1) to (3) can be easily obtained.

The oxygen ratio is preferably 500 to 650 Nm ³ per ton of feedstock oil, and more preferably 550 to 600 Nm ³ . When the oxygen ratio is within the above range, carbon black that satisfies the conditions (1) to (3) is easily obtained.

1000-1800 kg / hour is preferable and the supply amount of the raw material oil supplied into the furnace per unit time is more preferably 1200-1600 kg / hour. If the supply amount of the raw material oil supplied into the furnace per unit time is within the above range, carbon black satisfying the conditions (1) to (3) can be easily obtained.
The feed oil is preferably fed without being emulsified. Thereby, it is easy to obtain carbon black satisfying the conditions (1) to (3).

The furnace temperature is preferably 1250 to 1350 ° C, and more preferably 1300 to 1350 ° C.
Furnace pressure is preferably ^{15~45kg / cm 2, 25~35kg / cm} 2 is more preferable.

  The obtained carbon black is preferably dried in a nitrogen gas atmosphere. The drying temperature is preferably 300 to 900 ° C, more preferably 350 to 700 ° C, and particularly preferably 400 to 600 ° C. If a drying temperature is 300 degreeC or more, a volatile matter will decrease and a high electroconductivity provision effect will be easy to be acquired. When the drying temperature is 900 ° C. or lower, the degree of graphitization becomes small and high dispersibility is easily obtained.

  As the raw material oil, those usually used for the production of carbon black can be used, and examples thereof include coal-based hydrocarbons such as creosote oil and petroleum-based hydrocarbons such as ethylene bottom oil (EHE oil). Among these, EHE oil is preferable.

The BMCI value of the raw material oil is preferably 100 to 200, more preferably 120 to 180, and particularly preferably 130 to 160. If the BMCI value is 100 or more, the yield is difficult to decrease, which is preferable from an economic viewpoint. If the BMCI value is 200 or less, stable supply of raw materials is easy.
In addition, the BMCI value of the raw material oil is obtained by the following formula.
BMCI value = 48640 / K + 473.7S-456.8
However, in said formula, K is an average boiling point of raw material oil, and S is specific gravity of raw material oil.

  5-20 are preferable and, as for C / H ratio of raw material oil, 10-18 are still more preferable. If the C / H ratio is 5 or more, the yield is unlikely to decrease, which is preferable from the economic aspect. If the C / H ratio is 20 or less, stable supply of raw materials is easy.

As impurities of the feedstock oil, the sodium content is preferably 10 mass ppm or less, more preferably 5 mass ppm or less, and particularly preferably 3 mass ppm or less. If sodium content is 10 mass ppm or less, it is easy to suppress that many metal contents, such as iron, remain | survive in produced | generated carbon.
The iron content of the raw oil is preferably 10 mass ppm or less, more preferably 8 mass ppm or less, and particularly preferably 4 mass ppm or less. If the iron content is 10 mass ppm or less, it is easy to suppress the metal remaining in the carbon and adversely affecting the resin characteristics.
The content of nickel, copper and manganese in the raw oil is preferably 8 mass ppm or less, more preferably 4 mass ppm or less, and particularly preferably 2 mass ppm or less. If content of nickel, copper, and manganese is 8 mass ppm or less, it will be easy to suppress that a metal remains in carbon and has a bad influence on a resin characteristic.
The sulfur content of the raw material oil is preferably 1% by mass or less, more preferably 0.5% by mass or less, and particularly preferably 0.01% by mass or less. If the sulfur content is 1% by mass or less, it is easy to suppress adverse effects on the resin characteristics.

[resin]
The resin is not particularly limited, and may be a thermoplastic resin or a thermosetting resin.
Examples of the thermosetting resin include phenol, melamine, and epoxy.
Examples of the thermoplastic resin include polyolefin resins, elastomer resins, polystyrene resins, other general-purpose resins, engineering plastics, super engineering plastics, and the like.

  Examples of the polyolefin-based thermoplastic resin include olefin homopolymers or copolymers, and copolymers of olefins and other monomers. Specifically, for example, polyethylene resin such as high, medium, low density polyethylene, linear low density polyethylene, polypropylene resin, poly-1,2-ptadiene resin, ethylene-butene produced by high, medium, and low pressure methods. Examples thereof include copolymers, copolymers of ethylene, propylene or butylene and acrylates or methacrylates, those obtained by chlorinating these, or mixtures of two or more thereof. Among the polyolefin-based thermoplastic resins, a polyethylene resin and a polypropylene resin are preferable.

The elastomeric thermoplastic resins include ethylene propylene elastomers, olefin elastomers such as ethylene-propylene-diene rubber (EPDM) elastomers, styrene elastomers such as styrene-butadiene-styrene and styrene-isoprene-styrene, and polyamides. Examples include elastomers, urethane elastomers, and polyester elastomers.
Examples of the polystyrene-based thermoplastic resin include polystyrene, acrylonitrile-butadiene-styrene (ABS) resin, acrylonitrile-styrene (AS) resin, acrylonitrile-acrylic rubber-styrene (AAS) resin, and the like.

  Other general-purpose resins include polyvinyl chloride (PVC) resin, ethylene-ethyl acrylate (EEA) resin, ethylene-vinyl acetate (EVA) resin, acrylonitrile-ethylene-propylene rubber-styrene (AES) resin, and ethylene-vinyl alcohol resin. And polylactic acid.

Engineering plastics include polyamide resins such as 6-, 6,6-, 6,10-, 12-, and MXD-nylon resins, polyester resins such as polycarbonate resins, polyethylene terephthalate resins, polybutylene terephthalate resins, polyacetal resins, and modified resins. Examples include polyphenylene ether resin.
As super engineering plastics, polysulfone resin, modified polysulfone resin, polyphenylene sulfone resin, polyketone resin, polyether imide resin, polyarylate resin, polyphenylene sulfide resin, liquid crystal polymer, polyether sulfone resin, polyether ether ketone resin, Examples thereof include a polyimide resin, a polyamideimide resin, and a fluorine resin.

Examples of the polycarbonate resin include an aromatic polycarbonate resin obtained by reacting an aromatic dihydroxy compound with phosgene or a diester of carbonic acid, and an alicyclic polycarbonate resin using an alicyclic dihydroxy compound instead of the aromatic dihydroxy compound. Etc.
Aromatic dihydroxy compounds include 2,2-bis (4-hydroxyphenyl) propane, bis (4-hydroxyphenyl) methane, 1,1-bis- (4-hydroxyphenyl) ethane, and 2,2-bis (4 -Hydroxyphenyl) propane, 2,2-bis (4-hydroxy-3-methylphenyl) propane, 4,4'-hydroxybiphenyl and the like.
Examples of the alicyclic dihydroxy compound include isosorbide, spiroglycol, cyclohexyldiol and the like.

  Further, these resins may be blended and used for the purpose of ensuring physical properties according to the application. Specific examples include ABS / polycarbonate resin blends, polybutylene terephthalate resin / polycarbonate resin blends, polyphenylene ether resin / polyamide resin / styrene-butylene-styrene elastomer blends, and the like.

  60.0-99.5 mass% is preferable and, as for the ratio of resin in the conductive resin composition (100 mass%) of this invention, 70.0-97.0 mass% is more preferable. If the ratio of the said resin is more than a lower limit, the strength reduction of a conductive resin composition will be suppressed. If the ratio of the said resin is below an upper limit, the conductive resin composition which has the outstanding electroconductivity will be easy to be obtained.

[Other ingredients]
Other components include, for example, mica, glass fiber, silica, talc, calcium carbonate, zinc oxide, barium sulfate, to improve heat resistance, dimensional stability, rigidity, toughness, impact resistance, and mechanical strength. Inorganic fillers such as stainless steel, copper oxide, nickel, nickel oxide, and zirconia silicate can be blended. Also, molding of known antioxidants such as phenols and phosphoruss, metal soaps, lubricants such as fatty acid amide derivatives, etc., for the purpose of improving deterioration and moldability during kneading or aging of thermoplastic resin and carbon black A processing aid may be blended. In addition, known flame retardants, plasticizers, and the like can be used depending on applications.

  When the conductive resin composition of the present invention contains other components, the ratio of the other components in the conductive resin composition (100% by mass) of the present invention is preferably 0.1 to 40.0% by mass. 1.0 to 30.0 mass% is more preferable.

The method for preparing the conductive resin composition of the present invention is not particularly limited, and examples thereof include a method in which a resin, carbon black, and other components used as necessary are mixed and kneaded by a known method.
The conductive resin composition of the present invention may be formed into a pellet compound by, for example, melting and kneading each component. There is no restriction | limiting in particular as a method to make the conductive resin composition of this invention into a pellet-form compound, The method of using a well-known apparatus and equipment is employable. For example, each component is supplied to a kneader, melt-kneaded, extruded from a die, and pelletized using a pelletizer or the like.

Each component of the conductive resin composition of the present invention may be kneaded after being uniformly mixed with a premixer such as a tumbler or a Henschel mixer, for example, and specific components may be separately separated using a quantitative feeder or a capacity feeder. You may supply and knead | mix to a kneading machine.
Examples of the kneader include a single-screw extruder with a vent, a different-direction twin-screw extruder, a same-direction twin-screw extruder, a super mixer, a Banbury mixer, a kneader, a tumbler, and a kneader.
In the present invention, since the dispersibility of carbon black is good, a conductive resin composition in which carbon black is well dispersed in the resin can be easily prepared by a known kneading method.

It does not specifically limit as a method of manufacturing an electroconductive article using the electroconductive resin composition of this invention, For example, it can select suitably according to uses, such as injection molding and extrusion molding.
The use of the conductive resin composition of the present invention is not particularly limited, and examples thereof include an automotive conductive material, a semiconductor package, and a power cable.

If the conductive resin composition of the present invention described above is used, the carbon black satisfying the conditions (1) to (3) is used, so that the conductivity having both high mechanical strength and excellent surface smoothness and conductivity. A product can be manufactured.
Conventionally, as a good carbon black dispersion, acetylene black DBP oil absorption of 270 cm ^3/100 g less and a BET specific surface area of 350 meters ² / g less than the carbon black (hereinafter, referred to as "carbon black (a)".) Is commercially available, but carbon black (a) has a low conductivity imparting effect when blended with a resin. As the conductivity-imparting effect is high carbon black, DBP oil absorption of 340 cm ^3/100 g super and a BET specific surface area of 650 meters ² / g than the carbon black (hereinafter, referred to as "carbon black (b)".) It is commercially available However, the carbon black (b) has low dispersibility. The reason for the carbon black used in the present invention is not clear, but compared with the intermediate performance assumed from the dispersibility and conductivity of carbon black (a) and the dispersibility and conductivity of carbon black (b). Also have better dispersibility and conductivity. Thereby, it is thought that the said effect is acquired.

EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited by the following description.
[Measuring method]
(DPB oil absorption of carbon black)
The DPB oil absorption amount of carbon black was measured with a sample amount of 9 g under the conditions based on ASTM D 2414.

(BET specific surface area of carbon black)
The BET specific surface area of carbon black was measured under conditions based on ASTM D 3037.

(Carbon black ratio D ₉₀ / D _mod )
The carbon black ratio D ₉₀ / D _mod was measured by the aggregate diameter measuring method described in JIS K6217-6.
Specifically, a well-balanced carbon black was added to a 20 vol% ethanol aqueous solution to which 3 drops of a surfactant (“NONIDET P-40” manufactured by SIGMA CHEMICAL) was added, and the carbon black concentration was 0.01% by mass. A sample solution was prepared. The sample solution was subjected to a dispersion treatment for 20 minutes using an ultrasonic cleaner (ULTRASONIC STIRRING BATH: manufactured by LAKOMANUFACTURERING CO.) To obtain a carbon black slurry. After injecting 10 mL of spin solution (pure water) into a centrifugal sedimentation type particle size distribution measuring apparatus (“BI-DCP PARTIC LSIZ” manufactured by BROOK HAVEN INSTRUMENTS), and further injecting 1 mL of buffer solution (20 vol% ethanol aqueous solution), 1 mL of carbon black slurry was injected, centrifuged at 10000 rpm, and the Stokes equivalent diameter was calculated with a true specific gravity of 1.78. A histogram of the relative frequency of occurrence with respect to the Stokes equivalent diameter as shown in FIG. Had made.
A straight line B was drawn from the peak A of the histogram in parallel to the Y axis, and the intersection with the X axis of the histogram was taken as C. The Stokes diameter at C at this time is the mode diameter (D _mod ). In addition, a straight line E was drawn in parallel with the Y axis from the point D at which the integrated amount becomes 90% in this histogram, and the intersection with the X axis of the histogram was taken as F. Stokes diameter at F at this time, the D90 diameter _{(D 90).}

(Average primary particle size of carbon black)
The average primary particle diameter of carbon black was determined using a transmission electron microscope. Specifically, a carbon black sample was dispersed in chloroform for 10 minutes using an ultrasonic disperser of 150 kHz and 0.4 kW to prepare a dispersion sample, which was sprinkled and fixed on a carbon reinforced support film. This was photographed with a transmission electron microscope, and the particle size of 1000 or more carbon blacks was randomly measured using an Endter apparatus from an image magnified 50000-200000 times, and the average value was taken as the average primary particle size. .

(Carbon black volatiles)
The volatile matter of carbon black is a magnetic crucible (diameter 15 mm, height 30 mm, capacity 10 mL) and the lid is baked at 950 ± 20 ° C. for 30 minutes, and then cooled to room temperature (25 ° C.) in a desiccator. And the mass (M _A ) of the drop lid was accurately weighed to the nearest 0.1 mg. Next, 2 g of carbon black was pressed into a magnetic crucible so as not to exceed 2 mm below the lid, and the lid was dropped, and the mass (M _B ) was accurately weighed to the nearest 0.1 mg. Then, it is heated in an electric furnace at 950 ± 20 ° C. for 7 minutes, cooled to room temperature (25 ° C.) in a desiccator, and again weighed the mass (M _C ) to the nearest 0.1 mg, and the following formula To calculate the volatile content.
Volatiles _{(wt%) = (M B -M C} ) / (M B -M A)

(Carbon black ash)
The ash content of carbon black was measured under conditions based on ASTM D 1506.

(24M4DBP oil absorption of carbon black)
The test was carried out using a sample amount of 20 g under the conditions described in JIS K 6217-4.

(CTAB adsorption specific surface area of carbon black)
The measurement was carried out under the conditions described in JIS K 6217-3.

(Iodine adsorption amount of carbon black)
Measurement was carried out by the method described in JIS K 6217-1.

(PH measurement method for carbon black)
Accurately weigh carbon black 1g ± 0.01g to 0.01g, collect in a 20mL beaker, add 1mL ethyl alcohol and 10mL distilled water boiled in advance to make a dispersion of carbon black, cover with a watch glass And allowed to cool in a constant temperature room at 25 ° C. for 60 minutes. After confirming that the dispersion was at 25 ° C., using the pH meter calibrated with the pH standard solutions 4, 7, and 9, the reading value one minute after the start of the measurement was read.

[Raw oil]
The properties of the feedstock used in this example are shown below.
Type: EHE oil Initial distillation temperature: 198 ° C
10% distillation temperature: 220 ° C
50% distillation temperature: 279 ° C
C / H ratio: 13.5
Impurities: sodium mass 3 ppm, iron 4 mass ppm, nickel 2 mass ppm, copper 2 mass ppm, manganese 2 mass ppm, sulfur 10 mass ppm
BMCI value: 145

[Production Example 1]
Using a furnace, the feed rate of the feedstock oil (oil feed rate) to the furnace is 1400 kg / hour, the ratio of steam supplied to the furnace per ton of feedstock (steam ratio) is 250 kg / t, oxygen Carbon black was obtained with a ratio of 570 Nm ³ / t, a methane concentration of 0.70 vol%, a furnace temperature of 1335 ° C., and a furnace pressure of 30 kg / cm ² . Further, the obtained carbon black was dried in a nitrogen atmosphere at 450 ° C. The yield of carbon black per ton of feedstock was 223 kg / t.

[Production Examples 2 to 4]
Carbon black was obtained in the same manner as in Production Example 1, except that the oil supply amount, steam ratio, oxygen ratio, methane concentration, furnace temperature, and furnace pressure were changed as shown in Table 1.

[Production Example 5]
Using furnace furnace, the feed rate of emulsion feed oil into the furnace is 2222 kg / hour (feed rate as feedstock is 2000 kg / hour), the ratio of steam supplied to the furnace per ton of feedstock (steam ratio) Was 515 kg / t, the oxygen ratio was 635 Nm ³ / t, the methane concentration was 0.83 vol%, the furnace temperature was 1305 ° C., and the furnace pressure was 30 kg / cm ² to obtain carbon black. Further, the obtained carbon black was dried at 450 ° C. in a nitrogen atmosphere. The yield of carbon black per ton of feedstock was 130 kg / t.
DBP oil absorption, BET specific surface area, D _mod , D ₉₀ , ratio D ₉₀ / D _mod , average primary particle diameter, yield, ash content, CTAB adsorption specific surface area, ratio (CTAB) of carbon black obtained in Production Examples 1-5 / BET), 24M4DBP oil absorption, iodine adsorption, and pH of a 1 mass% aqueous solution are shown in Table 1.

[Example 1]
10 parts by mass of carbon black obtained in Production Example 1 and 90 parts by mass of polycarbonate resin (trade name “Iupilon S-3000”, manufactured by Mitsubishi Engineering Plastics Co., Ltd.) After kneading and extruding at 290 ° C. and cooling, a conductive resin composition was obtained as a cylindrical pellet compound by a pelletizer.

[Examples 2 to 4]
A conductive resin composition was obtained in the same manner as in Example 1 except that the carbon black used was changed as shown in Table 2.

[Comparative Example 1]
As carbon black for comparison, DBP oil absorption amount obtained in Production Example 5 324cm ³ / 100g, BET specific surface area of 800 m ² / g, the ratio _D 90 _{/ D mod} is _1.80 (D 90 = _0.200μm, A conductive resin composition was obtained in the same manner as in Example 1 except that 8 parts by mass of carbon black (D _mod = 0.111 μm) and 92 parts by mass of polycarbonate resin were used.

[Comparative Example 2]
As carbon black for comparison, DBP oil absorption of 193cm ³ / 100g, BET specific surface area of ^55m 2 / g, the ratio _D 90 _{/ D mod} is _{3.47 (D 90 = 0.406μm, D} mod = 0.117μm) A conductive resin composition was obtained in the same manner as in Example 1 except that 10 parts by mass of commercially available carbon black was used.

[Comparative Example 3]
As carbon black for comparison, DBP oil absorption of 193cm ³ / 100g, BET specific surface area of ^55m 2 / g, the ratio _D 90 _{/ D mod} is _{3.47 (D 90 = 0.406μm, D} mod = 0.117μm) A conductive resin composition was obtained in the same manner as in Example 1 except that 17 parts by mass of commercially available carbon black and 83 parts by mass of polycarbonate resin were used.

[Comparative Example 4]
As carbon black for comparison, DBP oil absorption of 166cm ³ / 100g, a BET specific surface area 256m ² / g, the ratio _D 90 _{/ D mod} is _{1.70 (D 90 = 0.292μm, D} mod = 0.172μm) A conductive resin composition was obtained in the same manner as in Example 1 except that 17 parts by mass of commercially available carbon black and 83 parts by mass of polycarbonate resin were used.

[Comparative Example 5]
Resulting carbon black of Comparative Example 3 and carbon black in Comparative Example 1 were blended in a weight ratio 59/41, DBP oil absorption of 280 cm ^3/100 g, BET specific surface area of 576m ² / g, the ratio _D 90 _{/ D mod} The conductive resin composition was the same as in Example 1 except that 12 parts by mass of carbon black having a value of 1.75 (D ₉₀ = 0.238 μm, D _mod = 0.136 μm) and 88 parts by mass of polycarbonate resin were used. Got.

[Comparative Example 6]
Resulting carbon black of Comparative Example 2 carbon black of Comparative Example 1 were blended in a weight ratio 52/48, DBP oil absorption of 280cm ³ / 100g, BET specific surface area of 443m ² / g, the ratio _D 90 _{/ D mod} Is the same as in Example 1 except that 14 parts by mass of carbon black and 86 parts by mass of polycarbonate resin with a D of 2.62 (D ₉₀ = 0.299 μm, D _mod = 0.114 μm) are used. Got.

[Volume resistivity]
A plate-shaped test specimen having a thickness of 3.2 mm, a length of 76 mm, and a width of 76 mm was produced by injection molding using the pellets of the conductive resin composition obtained in each example. Volume resistivity was measured according to ISO1853 using meter Model 2506A. It shows that it is excellent in electroconductivity, so that the value of volume resistivity is small.

[Surface smoothness]
Films having a thickness of 80 to 100 μm × width 10 cm × length 10 cm were produced by inflation molding using the pellets of the conductive resin composition obtained in each example. The film surface was observed visually, the number of carbon aggregates of 0.2 mm or more was counted, and the surface smoothness was evaluated according to the following evaluation criteria. In addition, it shows that it is excellent in the dispersibility of carbon black, so that the number of carbon aggregates is small.
“◯”: The number of carbon aggregates is less than 10.
“X”: The number of carbon aggregates is 10 or more.

[Mechanical strength]
A type 1 test body (length 80 mm × width 10 mm × thickness 4 mm, with notch) described in ISO 179 was prepared by injection molding using the pellets of the conductive resin composition obtained in each example, and ISO 179 / 1eA was prepared. A Charpy impact test was conducted in conformity. Higher Charpy impact strength indicates better mechanical strength.

Table 2 shows the DBP oil absorption, the BET specific surface area, the ratio D ₉₀ / D _mod , and the evaluation results of the carbon black used in the examples and comparative examples.

As shown in Table 2, the conductive resin compositions of Examples 1 to 4 using carbon black satisfying the conditions (1) to (3) have high mechanical strength and good surface smoothness and conductivity. It was.
On the other hand, in Comparative Example 1 using carbon black that satisfies the conditions (2) but does not satisfy the conditions (1) and (3), the dispersibility of the carbon black was insufficient and the surface smoothness was inferior. In Comparative Examples 2 to 4 using carbon black that does not satisfy any of the conditions (1) to (3), any one or more of conductivity, surface smoothness, and mechanical strength was inferior.
Further, in Comparative Examples 5 and 6 using a blend of two types of carbon blacks that satisfy the conditions (1) and (2) but do not satisfy the condition (3), the dispersibility of the carbon black is not sufficient, The surface smoothness was inferior.

Claims (1)

The following conditions (1) to (3) and carbon black 3.0 to 30.0 wt% which satisfies the conductive resin composition characterized by containing a 70.0 to 97.0% by weight thermoplastic resin .
(1) A BET specific surface area is 350 to 650 m ² / g.
(2) DBP oil absorption is 270-340 cm < ³ > / 100g.
(3) The ratio D ₉₀ / D _mod of the D90 diameter (D ₉₀ ) to the mode diameter (D _mod ) measured by the method for measuring an aggregate diameter described in JIS K6217-6 is 1.90 to 2.20. is there.

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