JP2838319B2 - Conductive thermoplastic resin composition and method for producing conductor - Google Patents

Description

Description: TECHNICAL FIELD The present invention can produce a thermoplastic resin composition composed of a thermoplastic resin and a specific carbon black and having a small variation in conductivity, without scattering of carbon black and with high productivity. Method and method for producing conductive carbon black-containing conductive resin composition having stable conductivity even in a high resistance region (surface specific resistance value of 10 ⁶ to 10 ¹⁶ Ω) in which conductivity control is difficult, and production of conductor It is about the method.

Background of the Invention Conductive thermoplastic resin products made conductive by blending carbon black with thermoplastic resins are mainly used in applications such as antistatic and electromagnetic wave sealing for electronic components, computers, VTRs and home appliances. In recent years, demand has increased significantly.

As a method for producing such a conductive thermoplastic resin, a method using a continuous twin-screw extruder has been conventionally performed.
As a method of supplying to an extruder in a production method using a continuous twin-screw extruder, a method in which carbon black and a resin are previously blended by a Henschel mixer or a tumbler mixer, and then supplied by various feeders, using a quantitative feeder A method of quantitatively supplying each of a resin and carbon black is generally used.
However, the resin and carbon black differ in the true specific gravity, bulk density, shape, etc., regardless of the method of supply, so that they are classified after being supplied to the blending stage or the extruder, and as a result, the concentration of carbon black in the composition is reduced. In some cases, a resin having stable conductivity with little variation in conductivity cannot be obtained and cannot be put to practical use.

Also, since the bulk density of carbon black used for imparting conductivity to the resin is very low, it contains a large amount of air, and when the carbon black is dispersed in the resin in the twin-screw extruder, a large amount of The air escapes and rises from the carbon black supply port, so that the carbon black scatters with the rise of the air. As a result, there are various problems such as a difference in the concentration of carbon black in the composition, a deterioration of the working environment due to the scattering of carbon black, and the floating carbon black fine particles adhering to the inside of the precision machine and destroying the internal electronic components. A point has also been pointed out. The rising of the carbon black has a correlation with the supply amount of the carbon black. Therefore, when the carbon black scatters, the supply amount must be reduced, and thus the production is reduced.

As a manufacturing method that can be applied when the raw material is a fine powder, an opening is provided downstream of the material supply port, and a screw configuration between the material supply unit and the opening does not compress the material,
A production method by adopting a constitution in which only melting or kneading is performed has been proposed (Japanese Patent Application Laid-Open No. 58-29644). However, in the case of the conductive carbon black used in the present invention, improvement can be made even by using this method. Could not.

Also, especially for the purpose of preventing the scattering of carbon black,
A method using a carbon black-rich resin masterbatch has been proposed (JP-A-54-58747, etc.), and the carbon black-rich resin masterbatch pellets are kneaded with a desired resin to impart conductivity. The method is generally performed. At this time, in consideration of economy and work efficiency, it is common to blend a small amount of masterbatch pellets with a large amount of heat-degradable resin, and then knead and mold to produce a conductive thermoplastic resin product.

However, in such method, it is relatively easy to have stable conductivity in the low-resistance region (surface resistivity 10 ² to 10 ⁴ Omega), the high resistance region (surface resistivity 10
It is very difficult to control the conductivity in ^{6 ~10 16 Ω).}

On the other hand, when the amount of the conductive carbon black contained in the conductive master batch pellets and the amount of the conductive carbon black in the desired conductive thermoplastic resin product are close to each other, the purpose is to use the master batch pellets, Instead of blending a small amount of thermoplastic resin into this,
In the same way as making master batch pellets, pellets containing conductive carbon black in the same amount as the conductive carbon black in the conductive thermoplastic resin product are manufactured in one step, and the conductive heat I was making plastic resin products. However, even with this method, it is relatively easy to provide stable conductivity in a low-resistance region (surface specific resistance value of 10 ² to 10 ⁴ Ω), but in a high-resistance region (surface specific resistance value of 10 ⁶ to 10 ^16). Ω), it was extremely difficult to control the conductivity.

DISCLOSURE OF THE INVENTION An object of the present invention is to provide a method capable of producing a thermoplastic resin composition having a small variation in conductivity at high productivity without scattering of carbon black.

The present invention provides a method for producing a conductive carbon black-containing conductive resin composition having stable conductivity even in a high resistance region (surface specific resistance value of 10 ⁶ to 10 ¹⁶ Ω) where conductivity control is difficult. The purpose is to do.

An object of the present invention is to provide a method for manufacturing a conductor having stable conductivity even in a high resistance region where the control of conductivity is difficult.

The above and other objects of the present invention will become apparent from the following description and examples.

The first aspect of the present invention is based on the finding that the above object can be achieved by a specific production method using a specific amount of carbon black and a continuous co-rotating twin screw extruder. is there.

That is, the present invention relates to a method for producing a conductive carbon black-containing thermoplastic composition in which conductive carbon black accounts for 5 to 50% by weight of a total of 100 parts by weight of conductive carbon black and thermoplastic resin. After supplying the thermoplastic resin to the continuous co-rotating twin-screw extruder to gel it, the conductive carbon black is forcibly supplied from the side feeder into the barrel of the continuous co-rotating twin-screw extruder. Before the conductive carbon black is completely dispersed in the thermoplastic resin, the mixture is deaerated at normal pressure from the deaeration holes provided in the continuous co-rotating twin-screw extruder. A method for producing a conductive carbon black-containing thermoplastic composition, characterized by obtaining a kneaded product of a thermoplastic resin and conductive carbon black.

In a second embodiment of the present invention, a conductive carbon black high blending resin masterbatch pellet is used in an amount of 0.
This is based on the knowledge that the above object can be effectively achieved by kneading with a small amount of thermoplastic resin such as 10 to 50%.

That is, the present invention relates to (a) a conductive resin masterbatch pellet in which conductive carbon black accounts for 5 to 50% by weight of a total of 100 parts by weight of conductive carbon black and thermoplastic resin; (A +
The present invention provides a method for producing a conductive thermoplastic resin composition, wherein kneading is performed at a weight ratio of b) / (a) in the range of 1.01 to 1.5.

In the second embodiment of the present invention, (a) out of 100 parts by weight of the total amount of the conductive carbon black and the thermoplastic resin,
A conductive resin masterbatch pellet in which conductive carbon black accounts for 5 to 50% by weight (b) a thermoplastic resin,
A method for producing a conductive material containing conductive carbon black, comprising kneading and extruding at a ratio of (a + b) / (a) in a range of 1.01 to 1.5.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows an outline of a continuous co-rotating twin-screw extruder for carrying out the present invention.

FIG. 2 shows an outline of another continuous co-rotating twin-screw extruder for carrying out the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION The thermoplastic resin used in the conductive resin masterbatch pellets of the first and second embodiments of the present invention is used for a conductive resin composition or a conductive product which is a final product. With appropriate strength and heat resistance, melt flow rate (MFR) is 1g / 10
min or more, preferably 8 to 2000 g / 10 min, particularly preferably 8 to 600 g / 10 min. In particular,
High, medium and low density polyethylene, polyethylene resins such as linear low density polyethylene, polypropylene resin, poly-1,2-butadiene resin, ethylene-butene copolymer,
Ethylene-vinyl acetate copolymer, ethylene and methyl-,
Polyolefin resins such as ethyl-, propyl- and butyl-copolymers with acrylates or methacrylates, or chlorinated products thereof, or mixtures of two or more of these; polystyrene resins, AB
Styrene resins such as S resin and AS resin; Polyester resins such as polyethylene terephthalate resin and polybutylene terephthalate resin; Polyamide resins such as 6-nylon resin and 6,6-nylon resin; Polysulfone resin, modified polysulfone resin, polyallyl Sulfone resin, polyketone resin, polyetherimide resin, polyarylate resin, polyphenylene sulfide resin, liquid crystal polymer,
Polyethersulfone resin; super-engineering resins such as polyetheretherketone resin, polyimide resin, polyamideimide resin, and fluororesin; polyvinyl chloride resin, thermoplastic urethane resin, polyacetal resin, polycarbonate resin, modified polyphenylene ether resin, etc. Can be 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 preferable, and polycarbonate is particularly preferable. Resin, polyethylene terephthalate resin, polybutylene terephthalate resin, polystyrene resin, polyphenylene sulfide resin, thermoplastic urethane resin, modified polyphenylene ether resin, and polyetherimide resin.

Further, the thermoplastic resin used for preparing the conductive carbon black masterbatch pellet (a) and the thermoplastic resin (b) for diluting the conductive carbon black (hereinafter also referred to as a diluted resin) may be the same or different. But it doesn't matter.

Here, the melt flow rate (MFR) is a value measured according to the measurement method for a resin for which a method for measuring the melt flow rate of each resin is specified in Japanese Industrial Standards, and a polypropylene resin, For polyethylene resin and ethylene-vinyl acetate resin, JISK6758 (230 ° C, 2.16 kgf), JISK6730 (190 ° C, 2.1
6Kgf), and for other polyolefin resins, JISK7210, Method A, Condition 4 (190 ° C, 2.16Kgf)
It measured according to. For resins not specified, the temperature shown in the table below using an apparatus described in JISK7210A method,
This is a value measured by load. Table 1 shows the measurement conditions.

Conductive carbon black used in the present invention,
DBP oil absorption is 200ml / 100g or more, preferably 340-70
It is 0ml / 100g. Among them, in the first embodiment, those having a specific surface area of 700 to 1500 m ² / g are more preferable,
Those having a specific surface area of 750 to 1300 m ² / g are more preferred. At this time, those having a bulk specific gravity of 160 g / l or less are preferable. Further, the conductive carbon black-containing thermoplastic composition according to the first aspect of the present invention and the conductive resin masterbatch pellet used in the second aspect of the present invention include a thermoplastic resin and a conductive carbon black in a total amount of 100. The conductive carbon black accounts for 5 to 50% by weight, preferably 5 to 20% by weight in the weight part.

The conductive carbon black-containing thermoplastic composition in the first embodiment of the present invention and the conductive resin masterbatch pellet used in the second embodiment of the present invention contain conductive carbon black and a thermoplastic resin as essential components. In addition, graphite can be contained. Here, graphite acts as a stabilizer for obtaining stable conductivity at high resistance, and preferably has an average particle size of 3 to 15 μm. The conductive carbon black-containing thermoplastic resin according to the first aspect of the present invention. The content is preferably 2 to 15% by weight in the composition and the conductive resin masterbatch pellets used in the second embodiment of the present invention. Also, an antioxidant, an anti-deterioration agent, an ultraviolet absorber, a lubricant and the like are used in an amount of 0.1 to 1 as long as performance is not impaired.
It can be contained in an amount of about% by weight.

As the conductive resin masterbatch pellets used in the second embodiment of the present invention, those having an arbitrary particle size can be used, but cylindrical pellets having a diameter of 2 to 4 mm and a length of 3 to 5 mm are used. Good to do. The thermoplastic resin may be of any size, but it is preferable to use the same size as the conductive resin master batch pellets.

In the production method according to the first aspect of the present invention, when the total barrel length of the co-rotating twin-screw extruder is 100, the thermoplastic resin is located at 0 to 10%, preferably 0 to 7% from the motor side. It is good to set the input port. The resin may be charged into the barrel by a natural fall from a hopper or may be forcibly supplied into the level, but it is preferable that the resin fall naturally.

In the first aspect of the present invention, after the thermoplastic resin thus supplied into the barrel is gelled by the kneading action of the screw installed in the barrel and external heating, the thermoplastic resin is supplied from at least one side feeder. The conductive carbon black is forcibly supplied into the barrel to disperse the conductive carbon black in the gelled resin. Here, any side feeder can be used as long as the conductive carbon black can be forcibly supplied into the barrel. However, it is preferable to use a method in which the conductive carbon black is forcibly supplied by a screw. Specifically, TWIN FEEDER 25 made by Nakatani Machinery
1 and so on. This side feeder is installed in the barrel where the resin is gelled. Normally, when the total barrel length of the extruder is 100, 29% 50% from the motor side, preferably 33% to 50% It is appropriate to install at the position. If the side feeder is installed at a position where the resin is not gelled, the carbon black fed from the side feeder will scatter from the resin inlet or deaeration hole, reducing productivity, and conductive heat with stable conductivity It is not preferable because a plastic resin cannot be obtained.
Similarly, in place of the feeder, an input port is provided at the same position, and a quantitative feeder is used.When carbon black is input by natural fall from the input port upper part, the carbon black is scattered from the input port to reduce productivity, Further, it is not preferable because a conductive thermoplastic resin having stable conductivity cannot be obtained.

In the first aspect of the present invention, before the conductive carbon black is completely dispersed in the thermoplastic resin, for example, from the installation position of the side feeder to 17% upstream to 23% downstream.
%, Preferably 13% to 17% of the barrel on the upstream side is provided with one or more deaeration holes, from which deaeration is performed under normal pressure. In addition, when providing a deaeration hole in the same position as a side feeder, it is preferable to provide an interval of at least 45 degrees in the circumferential direction. In particular, the deaeration hole is preferably provided at the top (upper) of the barrel. The size of the deaeration holes varies depending on the size of the extruder, but is suitably typically 1cm ² ~80cm ^2, preferably 1~16cm ^2. If the carbon black is introduced without providing the deaeration holes, the air contained in the carbon black escapes from the side feeder, and as a result, the carbon black cannot be introduced.

As the screw of the co-rotating twin-screw extruder used in the first embodiment of the present invention, a known screw having a diameter of 20 is used.
Generally, the extruder has a length of 20 to 50 times the diameter of mm to 150 mm, and a known extruder body and motor according to the size of the screw are used.

Known screw parts are also used as the screw parts of the extruder, and specific examples thereof include those described in Journal of the Japan Society of Plastics Processing “Molding”, Vol. 3, No. 6 (1991), pp. 431-403. There are element, right type (R-KD), left type (L-KD) and neutral type kneading disk (N-KD), and these are arranged in an appropriate order according to the properties of the resin to be used and the blending amount of carbon black. Can be used with In particular, neutral type kneading discs that only carry out kneading without carrying or back-feeding capability and / or
Alternatively, it is preferable to dispose a light-type kneading disc for carrying and kneading at a position where the side feeder is installed, because the carbon black is not scattered and the production amount is improved.

In the first embodiment of the present invention, the thermoplastic resin is introduced from the resin inlet provided at the above-mentioned position using a known feeder, and a conductive thermoplastic resin composition having stable conductivity is obtained. For the purpose, it is preferable to use a gravimetric quantitative feeder having a quantitative accuracy within ± 1%. In the first aspect of the present invention, the carbon black is forcibly supplied by a side feeder after the resin is gelled. In order to obtain a conductive thermoplastic resin composition having stable conductivity, the screw of the side feeder is rotated in advance so that it can be charged at a speed higher than the charging speed of carbon, and the quantitative accuracy of carbon black is within ± 1%. It is preferable to drop onto the screw of the side feeder by using a gravimetric quantitative feeder, and then to forcibly feed the extruder by the side feeder. The gravimetric quantitative feeder used for charging the resin and carbon black
It is particularly preferable to use an interlocking type in which the input amount of the other feeder changes according to the change of the input amount of one feeder, since the obtained conductive thermoplastic resin has more stable conductivity.

The temperature of the barrel of the co-rotating twin-screw extruder used in the first embodiment of the present invention is determined by the gelling temperature of the thermoplastic resin to be used, and is set to a temperature 30 ° C. to 150 ° C. higher than the gelling temperature of the resin. In order to obtain a resin composition having stable conductivity, the temperature from 10% upstream of the position of the barrel where the side feeder is installed to the barrel where the deaeration hole is installed is increased by adjusting the temperature of the resin. 60 ℃ ~ 15 than the gelation temperature
0 ° C., preferably 70 ° C. to 150 ° C. higher, and the temperature of the barrel downstream of the position where the deaeration holes are installed is 30 ° C. to
It is desirable to set the temperature to 70 ° C., preferably 30 ° C. to 60 ° C. higher. Also, the number of rotations of the screw is, for example, 100 to 3
It can be about 00 rpm.

In the first aspect of the present invention, after degassing at normal pressure, the kneading is continued, and the kneaded product of the thermoplastic resin and the conductive carbon black is discharged from the die in any form, for example, a sheet, a pellet, or a wire. It can be obtained in the form of a shape.

In the second aspect of the present invention, when kneading the conductive carbon black resin masterbatch pellets of the component (a) and the thermoplastic resin of the component (b), the total weight of the components (a) and (b) is as follows: , The masterbatch as the component (a) must be in a range of 1.01 to 1.5 times, preferably 1.05 to 1.5 times, more preferably 1.05 to 1.3 times, and most preferably 1.1 to 1.3 times. It is. If it is more than 1.5 times, the surface resistivity of the conductive resin composition or the conductor as the final product will rapidly increase.

As the conductive carbon black resin masterbatch pellets used in the second aspect of the present invention, those prepared by any method can be used, but those prepared according to the first aspect of the present invention are used. Is preferred.

Before kneading the conductive master batch pellets and the diluting resin or the like for producing the conductor of the second aspect of the present invention, it is preferable to uniformly mix the conductive master batch pellets and the diluting resin or the like. The mixing can be easily performed by a known method of dry-blending the master batch pellets and the diluting resin with a mixer such as a Henschel mixer or a tumbler. This homogeneous mixture is then kneaded, but can also be directly kneaded using a quantitative feeder without uniform mixing. The kneading is performed using a kneading device such as a Banbury mixer or a twin-screw extruder. The kneading temperature is higher than the melting temperature of the resin.
The mixture is kneaded for 5 to 30 minutes when the kneading machine is a mixer, and 20 seconds to 1 minute when the kneading machine is an extruder. After cooling, the mixture is formed into an appropriate shape such as a pellet, a powder, or a lump. By forming such a pet or the like by a known extrusion molding method such as injection molding, blow molding, or inflation molding, a conductor having a shape suitable for a use such as a sheet, a film, a plate, or a different shape can be obtained.

In the second aspect of the present invention, when a molding machine having both functions of kneading and extrusion is used, such as a twin-screw extruder, a mixture of the conductive masterbatch pellets and a diluting resin is used in a popper. And kneading and extrusion molding (including injection molding) can be performed in one step.

In the second aspect of the present invention, of the above production methods, (a) a conductive resin masterbatch pellet is produced using a twin-screw extruder, and then (a) a conductive resin masterbatch pellet and (b) a heat The mixture of the thermoplastic resin is kneaded using a twin-screw extruder (after uniform mixing or immediately without mixing), and the conductive resin pellets as an example of the conductive thermoplastic resin composition (preferably, It is preferable to manufacture a column having a diameter of 2 to 4 mm and a length of 3 to 5 mm). At this time, (a) the conductive resin masterbatch pellet and (b)
The cylinder of the twin-screw extruder used to knead the mixture of thermoplastic resin is divided into a melting section, a kneading section, and a die section. ), The temperature of the kneading part is set to be lower than the temperature of the melting part and the die part by 10 ° C. or more, preferably 20 to 50 ° C. The temperature of the melting portion and the die portion is 30 to 100 ° C, preferably 60 to 100 ° C, higher than the gelling temperature of the resin. Further, the screw rotation speed during kneading is preferably set to 100 to 300 rpm.

Further, in order to improve the heat resistance, dimensional stability, rigidity, and mechanical strength of the conductive thermoplastic resin composition and the conductor obtained by the present invention, graphite, mica, glass fiber, silica, talc, calcium carbonate, Inorganic fillers such as zinc oxide, barium sulfate, stainless steel, copper oxide, nickel, nickel oxide, and zirconia silicate can also be blended. Among these, glass fiber (length 1.5-6mm, diameter 5-5)
20μ) is preferred. It is desirable to use these inorganic fillers in a proportion of 5 to 300 parts by weight, preferably 7 to 50 parts by weight, based on 100 parts by weight of the total of the thermoplastic resin and the conductive carbon black. Further, for the purpose of improving the moldability and preventing deterioration during kneading of the thermoplastic resin and the conductive carbon black, known phenol-based, phosphorus-based antioxidants, metal soaps, lubricants such as fatty acid amide derivatives, and the like. Known flame retardants, plasticizers, and the like can be used depending on the molding aid and application. The above-mentioned molding aid, flame retardant, plasticizer and the like may be blended in the master batch, or may be added when the master batch and the diluting resin are kneaded.

According to the production method of the present invention, various conductive thermoplastic resin compositions such as conductive resin pellets, and conductive carbon black-containing conductors having stable conductivity particularly in a high resistance region are provided. Also, by using the method of the present invention, when producing the conductive thermoplastic resin composition and the conductor, there is no deterioration of the working environment due to the scattering of carbon, having good conductivity and resin strength. An excellent conductor is obtained.

The conductor obtained according to the present invention has a surface resistivity
^It has a conductivity of ³ to 10 ¹⁶ Ω, and especially has a stable conductivity in a high resistance region of 10 ⁶ to 10 ¹⁶ Ω. be able to.

Now, the present invention will be described in further detail with reference to Examples.
The present invention is not limited to these Examples. In addition, all compositions were shown by "% by weight".

Example 1 Four types of continuous co-rotating twin-screw extruders (screw diameter: 57 mm, L / D: 36, schematically shown in FIGS. 1A to 1D)
90 parts by weight of a polycarbonate resin (Teflon A-2200 manufactured by Idemitsu Petrochemical) and a bulk specific gravity of 140 g / 1, DP using a NR-II 57 mm co-rotating twin-screw vented extruder manufactured by Nakatani Machinery
B: 10 parts by weight of carbon black having an oil absorption of 370 ml / 100 g (specific surface area: 810 m ² / g) were charged by the method shown in Table 2, and a conductive resin composition was obtained at a screw rotation speed of 220 rpm.

In FIG. 1, 1 to 12: barrel zone, 13: die, 14: resin inlet, 15: sealed side feeder, 16: carbon black inlet, 17: deaeration hole (4 cm × 4 cm square), 18: deaeration Pores (4 cm x 4 cm square), 19: Motor. The length of each of the barrel zones 1 to 12 is the total length of the barrel.
It is one-twelfth of the length when 100.

The screw configuration is such that melting, kneading, and transporting are performed without compressing the material in barrel zones 1 to 5, kneading, compressing, and transporting in barrel zones 6 and 8, and compression and transporting in other cases. .

The charging method of the resin and the carbon black is as follows.

Injection method A: As shown in FIG. 1 (A), a mixture of resin and carbon black was fed from an injection port provided at 15 into a quantitative feeder (Arculate 602 manufactured by Kuma Engineering).
The mixture was dropped into a twin-screw extruder by allowing the mixture to naturally fall using a mold. Deaeration holes are provided at 17 positions.

Injection method B: As shown in FIG. 1 (B), a twin-screw extruder is obtained by allowing the resin to fall naturally from an inlet installed in 14 using a quantitative feeder (Arculate 602 type manufactured by Kuma Engineering). Inside, and in the figure, 15
Feeder (Twin F made by Nakatani Machinery)
EEDER251) screw is rotated so that it can be charged at a higher speed than the charging speed of carbon black, and a fixed-quantity feeder (Kuma Engineering's Acurate 602) is used.
), The carbon black was allowed to fall naturally on the screw, and was forcibly supplied into a twin-screw extruder by a side feeder. Deaeration holes are provided at 17 positions.

Injection method C: As shown in FIG. 1 (C), a twin-screw extruder is prepared by allowing the resin to fall naturally from an inlet installed in 14 using a quantitative feeder (Arculate 602 type manufactured by Kuma Engineering). Inside, and in the figure, 15
Feeder (Twin F made by Nakatani Machinery)
EEDER251) screw is rotated so that it can be charged at a higher speed than the charging speed of carbon black, and a fixed-quantity feeder (Kuma Engineering's Acurate 602) is used.
), The carbon black was allowed to fall naturally on the screw, and was forcibly supplied into a twin-screw extruder by a side feeder. Deaeration holes are provided at 18 positions.

Injection method D: As shown in FIG. 1 (D), a twin-screw extruder is obtained by allowing the resin to fall naturally from an inlet installed in 14 using a quantitative feeder (Arculate 602 type manufactured by Kuma Engineering). And in the figure, 16
Was supplied to the twin-screw extruder by allowing carbon black to fall naturally using a fixed-quantity feeder (made by Kuma Engineering, Inc., Model 602). Deaeration holes are provided at 17 positions.

 The temperature conditions of the twin screw extruder are as follows.

Temperature condition 1: barrel zone 1; frozen barrel zone 2-6; 32
0 ° C barrel zone 7-12; 280 ° C, die; 280 ° C Temperature condition 2: barrel zone 1; cooling barrel zone 2-6; 32
0 ° C barrel zone 7-12; 320 ° C, die; 280 ° C Temperature condition 3: barrel zone 1; cooling barrel zone 2-6; 24
0 ° C. Barrel zone 7 to 12; 280 ° C., die: 280 ° C. The screw parts of barrel zone 5 where the side feeder is installed are as follows.

4N: 4N type kneading disk made by Nakatani machine 41: 41 type screw element made by Nakatani machine 3N: 3N type kneading disk made by Nakatani machine 31: 3R type kneading disk made by Nakatani machine Table 2 shows thermoplastic resin and carbon black. Injection method, type of screw parts at the same position as the side feeder is installed, set temperature conditions for each barrel, gelation state of resin at position 5 in FIG. 1, maximum discharge amount when carbon black is not scattered at all , Discharge amount
The graph shows the scattering state of carbon black and the volume resistivity value of the obtained conductive resin composition at 80 kg / hr.

In addition, the gelation state of the resin is represented by ○ when the resin is gelled at the position 5 in FIG. 1 and as x when the resin is not gelled.

The scattering state of carbon black was evaluated as 飛 when the carbon black did not scatter, and as x when the carbon black scattered violently. Further, the volume specific resistance value is obtained by press molding the obtained thermoplastic resin composition.
Five samples of 10 cm × 10 cm × 0.2 cm were prepared, and the volume resistivity values of these samples were measured according to the measurement method of SRIS-2301. The maximum value and the minimum value are shown in Table-2.

From the results in Table 2, according to the method of the present invention, there is no scattering of carbon black, the discharge rate is 110 to 120 kg / hr, the productivity is good, and the conductive thermoplastic resin composition obtained by this method is It can be seen that the material shows stable conductivity without variation in the volume resistivity. On the other hand, the comparative examples No. 6 (a method in which carbon black is spontaneously dropped from the inlet at the same barrel position instead of the side feeder) and No. 7 (a method in which carbon black is spontaneously dropped from the inlet into which resin is injected) No. 8 (method where there is no deaeration hole at position 17) and No. 9 (method when the resin is not gelled at the position where carbon black is injected by the side feeder) is 80 kg. In the case of / hr, the carbon black scatters violently, and the discharge amount must be reduced to 1/2 to 1/3 as compared with the production method of the present invention in order to prevent the scattering, so that the productivity may be reduced. Recognize.

Further, even in a conductive thermoplastic resin composition produced with reduced productivity, the variation in conductivity is as high as 4 to 55 times (maximum value of volume resistivity / minimum value of volume resistivity), which is not practical.

Example 2 A continuous co-rotating twin-screw extruder (screw diameter: 57 mm, L / D: 36, NR-II 57 mm manufactured by Nakatani Machinery Co., Ltd.) equipped with a resin inlet, a deaeration hole, and a forced side feeder shown in FIG. Using a co-rotating twin-screw vented extruder), a predetermined amount of thermoplastic resin is charged from the inlet of 33 by the same method as in Example 1, and a predetermined amount of carbon black is forcibly forced by 34 side feeders. To obtain a conductive resin composition at a screw rotation speed of 220 rpm. In the figure, the glass fiber inlet 36 was closed in the case of a composition containing no glass fiber.

The screw configuration is such that the barrel zones 20 to 24 of FIG. 2 are configured to melt, knead, and convey the material without compression, the barrel zones 25 and 27 are configured to knead, compress, and convey, and otherwise perform the compression and conveyance. The configuration was adopted. In addition, barrel zone
The length of each of the zones 20 to 31 is one-twelfth of the length of the barrel when the total length of the barrel is 100.

Table 3 shows the composition, the type of screw parts at the same position where the side feeder is installed, the set temperature conditions for each barrel zone, the gelled state of the resin at the positions shown in FIGS. 2 and 34, and when carbon black does not scatter. Maximum discharge rate,
It shows the volume resistivity value of the obtained conductive resin composition.

The gelation state and the volume resistivity of the resin were evaluated in the same manner as in Example 1.

The thermoplastic resin used in Example 2, carbon black,
The types of glass fibers and the set temperature of the barrel of the twin-screw extruder are shown below.

Thermoplastic resin used Polypropylene resin (PP): Idemitsu Polypro J-750H
(Idemitsu Petrochemical) Polybutylene terephthalate resin (PBT): Toray PBT14
01X04 (manufactured by Toray) Modified polyphenylene ether resin (M-PPE): Noryl 115 (manufactured by Nippon GE Plastics) Polyetherimide resin (PEI): Ultem 1010 (manufactured by Nippon Gee Plastic) Polyethylene terephthalate resin (PET): Viropet EMC307 × 04 (Toyobo) Glass fiber: CS03MA416 (made by Asahi Fiberglass) Carbon black A: Bulk specific gravity: 140 g / 1, specific surface area: 810 m ² /
g (DBP oil absorption: 370 ml / 100 g) Carbon black B: Bulk specific gravity: 125 g / l, specific surface area: 1240 m ²
/ g (DBP oil absorption: 480 ml / 100 g) Carbon black C: Bulk specific gravity: 250 g / l, specific surface area: 70 m ² / g (DBP oil absorption: 210 ml / 100 g) Carbon black Temperature condition 4: barrel zone 20; cooling, barrel zones 21-26;
280 ° C, barrel zone 27-31; 240 ° C, die; 240 ° C Temperature condition 5: barrel zone 20; cooling, barrel zone 21-26;
320 ° C, barrel zone 27-31; 280 ° C, die; 280 ° C Temperature condition 6: barrel zone 1; cooling, barrel zone 2-6; 38
0 ° C, barrel zone 7-12; 370 ° C, die: 370 ° C Example 3 A predetermined amount of carbon black and a thermoplastic resin were kneaded with a twin-screw extruder at a cylinder temperature of 180 to 380 ° C. using the charging method B of Example 1, screw parts (position 5): 4N, and after cooling. A columnar conductive master batch was obtained using a pelletizer. Tables 4 to 6 show the compositions of the master batch.

The following were used as carbon black and resin.

Carbon black A (CB-A): carbon black with DBP oil absorption of 480 ml / 100 g (Ketjen Black EC600JD manufactured by Ketjen Black International Co., Ltd.) carbon black B (CB-B): carbon with DBP oil absorption 370 ml / 100 g Black (Ketjen Black EC manufactured by Ketjen Black International Co., Ltd.) Polypropylene resin (PP): Sumitomo Chemical, Sumitomo Noblen AZ-564 Polycarbonate resin (PC): Idemitsu Petrochemical, Toughlon A-2200 polyetherimide resin (PEI): Made by Japan GEP, Ultem
1010−100 Example 4 The PP master batch and the PP resin of Example 3 were mixed as a diluting resin so as to have a predetermined dilution ratio. This mixture is supplied to a twin-screw extruder, and the extruder cylinder is divided into a melting portion, a kneading portion, and a die portion, and the respective temperatures are set to 250 ° C. in the melting portion, 220 ° C. in the kneading portion, 240 ° C. in the die portion, and the screw rotation speed. Kneaded at 200 rpm. After cooling, a cylindrical pellet (diameter 2 mm, length 3 mm) was obtained using a pretizer. The pellets are supplied to an injection molding machine, and a predetermined mold is used.At a cylinder temperature of 180 to 220 ° C., 7.5 cm × 7.5 cm × 0.3 c
m conductors were obtained.

In Comparative Examples, conductors were obtained in the same manner as described above for dilution of master batches Nos. 5 and 6. No.7, 8
About, about PP and each carbon are blended by a tumbler, this mixture is supplied to a twin screw extruder,
180 ° C, Kneading section 210 ° C, Die section 180 ° C, Screw rotation speed 2
The mixture was kneaded at 00 rpm, and thereafter, a conductor was obtained in the same manner as described above. Table 7 shows the measurement results of the composition and the surface resistivity of the conductor.

In addition, the surface specific resistance value showing conductivity was measured according to ASTM D-257.

As shown in Table 7, in the present invention in which the masterbatch having each carbon black concentration is diluted with the PP resin at a low magnification, that is, 1.01 to 1.5 times, good conductivity (surface resistivity) is obtained even in a region where the amount of carbon after dilution is small. Value). On the other hand, a comparative example in which the dilution ratio is 1.6 times or more (Nos. 5 and 6)
In, when the amount of carbon after dilution decreases, the conductivity rapidly deteriorates. Also, knead only once without diluting
In Nos. 7 and 8, the surface characteristic value of the obtained conductor has a large fluctuation width and lacks practicality. As described above, according to the present invention, the high resistance region (10 ⁶ to 10 ^{16) which} is very difficult to control
Ω), a compound having stable conductivity can be obtained.

Example 5 The PC master batch and the PC resin of Example 3 were mixed as a diluting resin so as to have a predetermined dilution ratio. This mixture is supplied to a twin-screw extruder, and the extruder cylinder is divided into a melting portion, a kneading portion, and a die portion, and the respective temperatures are set to 330 ° C. in the melting portion, 280 ° C. in the kneading portion, 290 ° C. in the die portion, and the screw rotation speed. Kneaded at 200 rpm. After cooling, a cylindrical pellet (diameter 2 mm, length 3 mm) was obtained using a pelletizer. The pellets are supplied to an injection molding machine, and a predetermined mold is used.At a cylinder temperature of 280 to 300 ° C., 7.5 cm × 7.5 cm × 0.3 c
m conductors were obtained.

In Comparative Examples, conductors were obtained in the same manner as described above for dilution of the master batches Nos. 17 and 18. No.1
For 9 and 20, PC and each carbon were blended by a tumbler, and this mixture was supplied to a twin screw extruder.
Kneading was performed at 280 ° C. in the melting part, 320 ° C. in the kneading part, 290 ° C. in the die part, and at 200 rpm of the screw. Thereafter, conductivity was obtained in the same direction as above. Table 8 shows the measurement results of the composition and the surface resistivity of the conductor.

In addition, the surface specific resistance value showing conductivity was measured according to ASTM D-257.

From Table-8, it can be seen that in the present invention, in which the masterbatch having each carbon black concentration is diluted with PC resin at a low magnification, that is, 1.01 to 1.5 times, good conductivity (surface resistivity) is obtained even in a region where the amount of carbon after dilution is small. Value). On the other hand, a comparative example in which the dilution ratio is 1.6 times or more (No. 17, 18)
In, when the amount of carbon after dilution decreases, the conductivity rapidly deteriorates. Also, knead only once without diluting
In Nos. 19 and 20, the surface resistivity of the obtained conductor has a large fluctuation width and lacks practicality. Thus, according to the present invention, the high resistance region (10
⁽⁶ to 10 ¹⁶ Ω), a compound having stable conductivity can be obtained.

Example 6 The PEI master batch and the PEI resin of Example 3 were mixed as a diluting resin so as to have a predetermined dilution ratio. The mixture is supplied to a twin-screw extruder, and the extruder cylinder is divided into a melting part, a kneading part, and a die part, and the respective temperatures are set to 330 ° C. in the melting part, 350 ° C. in the kneading part, 380 ° C. in the die part, and the screw rotation speed. Kneaded at 200 rpm. A columnar pellet (diameter 2 mm, length 3 mm) was obtained using the cooled pelletizer. The pellets are supplied to an injection molding machine, and a predetermined mold is used.At a cylinder temperature of 380 to 400 ° C., 7.5 cm × 7.5 cm × 0.
A 3 cm conductor was obtained.

In the comparative examples, the conductors were obtained in the same direction as above for dilution of the master batches No. 29 and No. 30. No.3
For 1 and 32, PEI and each carbon were blended in a tumbler, and this mixture was fed to a twin screw extruder,
Kneading was performed at 340 ° C. in the melting part, at 360 ° C. in the kneading part, at 350 ° C. in the die part, and at a screw rotation speed of 200 rpm. Table 9 shows the measurement results of the composition and the surface resistivity of the conductor.

In addition, the surface specific resistance value showing conductivity was measured according to ASTM D-257.

From Table-9, it can be seen that in the present invention in which the masterbatch having each carbon black concentration is diluted at a low magnification, that is, 1.01 to 1.5 times, the PEI resin has good conductivity (surface resistivity) even in a region where the amount of carbon after dilution is small. Value). On the other hand, a comparative example in which the dilution ratio was 1.6 times or more (No. 29 to 3)
In (0), when the amount of carbon after dilution decreases, the conductivity rapidly deteriorates. Further, in Nos. 31 to 32 in which the mixture is kneaded at a time without dilution, the surface resistivity of the obtained conductor is large and the practicability is low. in this way,
According to the present invention, a compound having stable conductivity can be obtained even in a high resistance region (10 ⁶ to 10 ¹⁶ Ω) where control is extremely difficult.

Example 7 A predetermined amount of carbon black, graphite, and a thermoplastic resin were charged at a cylinder temperature of 280 ° C. using a twin-screw extruder at a screw part (position 5): 4 N in the charging method B of Example 1.
After kneading at 380380 ° C. and a screw rotation speed of 200 rpm, and cooling, a columnar conductive masterbatch pellet was obtained using a pelletizer. The graphite was charged by the same charging method as that for carbon black. Table 10 shows the composition of the conductive master batch. In addition, carbon black and resin
The following were used:

Carbon black B (CB-B): DBP oil absorption 370ml / 100g Graphite: made of Chuetsu graphite, artificial graphite GX-6 Shape: scale, average particle size: 6 μm Polyetherimide resin (PEI): made by Japan GEP, Ultem
1010-100 Polybutylene terephthalate resin (PBT): manufactured by Toray, Toray PBT1401X04 Modified polyphenylene ether resin (MPPE): Japan GEP
Made, Noryl 115 Polyethersulfone resin (PES): Amoco Japan Limited, UDEL P-1700 Polyetheretherketone resin (PEEK): ICI Japan, VICTREX PEEK 150G Example 8 The various master batch pellets, diluent resin and glass fiber of Example 7 were supplied to a twin-screw extruder according to the composition shown in Table 11, and the cylinder temperature was 280 to 380 ° C and the screw rotation speed was 20.
Kneaded at 0 rpm. After cooling, cylindrical pellets were obtained using a pelletizer. The pellets are supplied to an injection molding machine, and a cylinder temperature of 280
A conductor of 7.5 cm × 7.5 cm × 0.3 cm was obtained at a temperature of 400 ° C., and the surface specific resistance was measured. Table 11 shows the composition and the surface resistivity of the conductor.

 The following glass fibers were used.

Glass fiber: made of Asahi fiber glass, CS03MA416

──────────────────────────────────────────────────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-62-297353 (JP, A) JP-A Heisei 7-53767 (JP, A) JP-A-9-296117 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) B29C 47/00-47/96 B29B 7/00-7 / 94

Claims (2)

(57) [Claims] 1. A conductive resin masterbatch pellet in which (a) conductive carbon black accounts for 5 to 50% by weight of a total of 100 parts by weight of conductive carbon black and thermoplastic resin, and (b) thermoplastic resin (A + b) /
A method for producing a conductive thermoplastic resin composition, wherein the kneading is carried out in such a manner that the weight ratio of (a) is in the range of 1.01 to 1.5. 2. A conductive resin masterbatch pellet in which (a) conductive carbon black accounts for 5 to 50% by weight of a total of 100 parts by weight of conductive carbon black and thermoplastic resin, and (b) thermoplastic resin (A + b) /
A method for producing a conductive material containing conductive carbon black, comprising kneading and extruding at a ratio of (a) in a range of 1.01 to 1.5.