JPS6131462A - Electroconductive composition - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to polymeric compositions having electrically conductive properties.

This composition is used in the tire manufacturing industry and cable manufacturing industry.

In the rubber industry manufacturing industry, as aircraft and automobile tires, and as a cable braided wire to replace copper.
It is also useful for manufacturing antistatic films, electrodes, sensors, heating elements, and fuel tanks.

Many countries are currently interested in producing this conductive composition. This is because compositions of this type combine the advantages of different components such as polymers and metals.

These compositions are characterized by high corrosion resistance, processability into molded articles, scales that can be used with multiple deformations, and can be substituted for non-ferrous metals and precious metals that are in short supply.

Known conductive compositions contain a polymeric matrix and a filler. As polymeric substrates, elastomers (often silicone elastomers) are used, as well as thermoplastic resins (polyethylene, polypropylene, copolymers thereof), phenol-formaldehyde resins and epoxy resins. Carbon blacks such as acetylene black, gas black, lamp black, and channel black are used as conductive fillers. The carbon black surface is treated with various reagents to improve the conductivity, elasticity and durability of the conductive composition.

Canric Betrix Chemicals has developed a complete range of organotitanates for treating fillers to improve the electrical conductivity and other properties of conductive compositions (P
last, Technol, 1975, 22
゜No, 8. p. 71).

To improve the conductivity of carbon black as a filler, calcium, barium,
It has been proposed in many publications to introduce strontium in the compound or elemental state (UK Patent No. 2
, 098,972 and 2,094,773).

In recent years, “Alz□ Ni Chemie, N1ed
erlande” Trademark sold by Ke
tjen-black E, C,'' carbon black is widely used as a filler. It is used in hydrocarbon materials with special additives that ensure high porosity and large surface area due to the presence of a large number of hollow particles. It is a gas black obtained as a result of burning carbon black.This carbon black "Ketjenblack E, C," is 0
．． It has an electrical resistance of 0.005 ohm meter (at a density of 18015 m''), its yield is 5%, the price is 2.
It costs 500 dollars. This is a small-scale production and difficult to obtain. This carbon per 100 parts by weight of polymer
A conductive composition containing 15 parts by weight of black has an electrical resistance of less than 0.1 ohm meter (U.S. Pat.
, 723.

(See No. 355).

In a known method of manufacturing carbon-plastic electrode structures for electrochemical devices (U.S. Pat. No. 4,164,068), the trademarks "KetJenblack E, C,
(Nouri Chemical Co., New York) and trademark "Vulkan The carbon-plastic sheet has an electrical resistance within the range of 0.001 to 0.05 ohmmeter.

Hemispherical carbon black with a surface area of 900 m”/f (this is “Ketjenblack E, C
, 7 parts by weight (corresponding to the properties of carbon black) and having an electrical resistance in the range of 0.01 to 1.00 ohm meters (U.S. Pat. No. 4,277).
3,097) is publicly known.

Methods are known for producing polymeric compositions having an electrical resistance of less than 10.0 ohm meters by filling polyurethane resins, epoxy resins and phenol formaldehyde resins KO, 15-2% by weight of conductive carbon fibers. (See British Patent No. 1,570,249).

By filling polyethylene, polypropylene, and polyurethane with graphite and dust black,
．． A method is known (see Japanese Patent No. 55-26503) for producing flexible sheet materials with a thickness of 0.15 to 0.20 m having an electrical resistance in the range of 0.001 to 1 ohm meter.

Semiconductor layer of a cable insulation based on a thermoplastic filled with modified hesitating additives and carbon black with a specific surface area of 70-901 and having a resistance of 4.5-5.0 ohm meters A conductive composition for the formation of (FRG Percent No. 2,845,671) is known.

U.S. Pat. No. 3,723,355 teaches conductive polymer compositions and methods of making the same. This composition has improved extrusion properties and abrasion resistance.

The composition contains 100 parts by weight of elastomer and 40 to 4 parts by weight of elastomer.
00 parts by weight of non-conductive filler and 300-1500<η
from 2 to 15 parts by weight of gas-treated carbon with a surface area of 3-/l, a pore porosity of 3-/l, and micropores of 2-4tr4/l, as well as l:1 for gas-treated carbon.
and a plasticizer in a proportion of . Optimal result for resistivity δ = 0.4 by loading 100 parts by weight of elastomer with 15]i parts of gas treated carbon and 100 parts by weight of alumina (in the absence of triethanolamine) ohm-meter) is obtained.

As is clear from the prior art cited above, the immediate electrical conductivity of polymer compositions is primarily dependent on the electrically conductive filler.

They rely on special carbon blacks with high structure and large surface area, and on mixtures of carbon black with graphite and noble metal powders. Bt) carbon black requires large investments for its production, and this type of carbon is therefore expensive and difficult to obtain. These carbons also have low processability, thus hindering their distribution in the polymer matrix IJ lux. This creates difficulties in the preparation of polymer compositions and also impairs the resistivity stability of these compositions. The conductivity level of N-coalized compositions containing such carbon black is 0.000.
01-108 ohm meters, but their actual value is unknown since there is no data regarding the degree of compaction and method of measurement of samples made of these compositions.

It is an object of this invention to provide a conductive composition that has low resistivity and is stable during processing and over time.

This object contains a polymeric matrix and conductive carbon black, and according to the invention the carbon is between 0.18 and 0.5
By mass, % of boron.

60~110rr? The above object is achieved by a conductive composition having a specific adsorption area of /r and the proportions of each component in parts by mass as follows.

Polymeric Matrix 100 Conductive Carbon Black 38-240 The carbon black used in the conductive composition according to the present invention has excellent conductivity, excellent processability during its incorporation stage, and also has excellent conductivity within the polymer matrix. Uniform 1! distribution. Because of these fillers, the conductive composition has a resistivity that is stable over time and during processing steps, which is equal to 0.007 to 0.01 ohm meter for extrudates and for sheets. For materials and compression molded articles, it is equal to 0.0006 to 0.004 ohm meters.

Furthermore, these electrically conductive compositions have excellent mechanical strength and flexibility, so that they can be used in the aircraft industry, the cable industry, the tire manufacturing industry and other industries.

In order to expand the range of conductive compositions used in various industrial fields, natural rubber, isoprene rubber, butadiene-nitrile rubber, ethylene-10 pyrene rubber, fluorocarbon rubber, urethane rubber, chloroprene rubber,
silicone rubber or mixtures thereof, and 1 to 3
It is desirable to contain 5 to 40 parts by weight of cross-linking agent and 5 to 40 parts by weight of stringing agent.

To use the electrically conductive composition according to the invention for producing cable braiding with polyethylene insulation of the strands!
It is desirable to contain a mixture of polyvinyl chloride plasticized resin and butadiene-nitrile rubber in the following component ratio (x lid part) as the combined substrate.

Polyvinyl chloride plasticized resin 80-90 Butadiene-nitrile rubber 10-20 Conductive carbon black 100-110 In order to use the conductive composition of the present invention for the production of braided wires for high-voltage cables, polyethylene as the polymer substrate is used. and a styrene/divinyl copolymer in the following component proportions (]i parts by weight).

Polyethylene 45-55 Styrene/divinyl copolymer theta 45-55 Conductive carbon black 38-45° As stated above, the electrical conductivity of the polymer composition is primarily dependent on the electrically conductive filler. To produce such fillers, we chose to chemically modify carbon black, which itself is a semiconductor. Carbon black is characterized by a decrease in electrical conductivity in the presence of impurities having atoms capable of chemically bonding with carbon atoms in the defect sites of the carbon atoms' crystal lattice. The receptor additives of choice are boron compounds, which are introduced into the composition of carbonaceous materials without following stoichiometric rules. During the thermal decomposition step of boron compounds, the boron atoms still in the active state capture electrons belonging to carbon atoms. The efficiency of this boron atom increases with increasing reaction temperature.

In order to obtain conductive carbon black that has high conductivity and is evenly distributed in the IJ lux part and has excellent processability in the carbon coalescence stage and the polymer matrix at a high filling degree,
The Inventors modified Furnace Black. This type of carbon black has an adsorption surface area of ω~110ff1″/l, a particle size of 3E1 to 42 nm, a pH of the aqueous suspension of 6 to 9, a dibutyl phthalate adsorption rate of 95 to 125 +d/r, 1. The carbon black aqueous solution is treated with a 5% aqueous solution of borax or boric acid and then dried at a temperature of 110-120°C, with a roughness coefficient of 13-1.18. By treating the carbon in a weakly reducing medium with
~0.5 weight: Carbon black bound with 1% boron was obtained. The specific adsorption surface area of this carbon black is α) ~
The particle size was 110 m'/r, the particle size was 3 ONm, the dibutyl phthalate adsorption rate was 120 m1/f, the roughness coefficient was 1.2, and the pII of the aqueous suspension was 7.0.

This chemically bonded boron content ensures an electrical conductivity of the carbon black of 0.00017 ohms (bulk density 400 Kq/nl).

Unlike known carbon black, this invention (
The carbon black produced without increasing the surface area (relative to the starting furnace black) obtains high and stable electrical conductivity and good distribution ability within the polymer matrix. This is the result of introducing the boron acceptor additive in the active atomic state into the carbon structure.

To prepare the 4'It composition according to the present invention, carbon is chemically combined with 0.18-0.5% by weight of boron and conductive carbon black having a specific adsorption surface area of 60-110 tf/r is used. Introduced in portions into the polymer matrix in a ratio of 100:38 to 240 (parts by weight), respectively.
Mix with the polymeric substrate at The mixed method is primarily determined by the nature of the polymer matrix. The following rubbers or other mixtures can be used as polymeric substrates. Natural rubber, isoprene rubber, phthadiene-nitrile rubber, ethylene-propylene rubber, fluororubber, chloroprene rubber, urethane rubber, silicone rubber. When these rubbers are mixed with the carbon black, -5 to 40 parts by weight of plasticizer and 1 to 3 parts by weight of crosslinking agent are introduced.

The rubber mix obtained after extrusion and vulcanization under appropriate conditions maintains the physical and technical parameters of the vulcanizate while maintaining zero
．． It has a stable electrical resistance within the range of 0.007 to 0.01 ohm meters.

Due to the ability of this chemically modified (boron-modified) carbon black to be well distributed in the IJ lux section, it is possible to 0.0006 to 0.004 while retaining the excellent physical-mechanical properties of sulfur
Conductive compositions and compression molded sheet products with stable resistivities reaching 1 ohm were obtained.

When producing a conductive composition from a polyvinyl chloride plasticized resin consisting of polyvinyl chloride together with plasticizers and stabilizers, the following proportions ( (parts by weight) of butadiene-nitrile rubber are also introduced.

Polyvinyl chloride plastic resin 80~90 Butadiene-nitrile rubber 10~20 Conductive carbon black 110~100゜The thus obtained mix was extruded to give 0.05~0.0
The cable is formed into a braided wire having a resistivity of 7 ohms. When 100 parts by weight of polyvinyl chloride plastic resin is filled with 240 parts by weight of the above carbon black, a conductive sheet and a grating are produced by rolling, followed by compression molding, which has a thickness of 0.007 to 0.001.
It has a stable electrical conductivity of one ohm meter, and various electrical industrial parts can be manufactured from it.

If a polyethylene polymer matrix is used for the conductive composition according to the invention, the polyethylene is premixed with the styrene/divinyl copolymer in a ratio of 45:55 (parts by weight) by milling. The above carbon black was added to the mix thus prepared and the polymer substrate 1
It is introduced at a ratio of 45 parts by weight to 00 parts by weight. Cable braids extruded from such conductive compositions have stable resistivities in the range of 0.05 to 1.00 ohm meters.

The simple method has a full range of properties depending on the polymer matrix used and the degree of filling, and for extrudates 0.0
Range of 0.07 to 0.01 ohm meters.

0.0006 to 0.00 for sheets and compression molded products.
Conductive compositions were prepared that were stable over time and had resistivities that were stable during processing steps in the range of 0.004 ohm. The conductive compositions produced by this invention combine high conductivity properties with sufficient mechanical strength and flexibility and can also be used as a material in cable braids to replace copper, as well as in fuel tanks, aircraft and automobile tires, etc. Used as a material in the manufacture of various antistatic products, electrodes, sensors, and heating elements.

Example 1゜ Natural rubber plastic resin (65 parts by weight) and butadiene-nitrile rubber (35 parts by weight) were mixed with zinc white (4 parts by weight),
A rubber mixer was charged with stearic acid (3 parts by weight), Neo 123 equivalent parts of carbon black (110 parts by weight), and a weighted section of dibutyl phthalate. The initial mixing temperature is 60-70°C, the final temperature is 100-110°C, and the mixing time is 14 minutes.

Prior to extrusion, 3.99 ultax and 6.2 f per rim of the rubber mix were introduced into the rubber mix. This rubber mix is 0.4~0.30
It has a plasticity of 1.3r/i and an extrudability of 1.3r/i.

The optimum vulcanization at a temperature of 160° C. is 4 minutes. The vulcanizate has a tensile strength of 9.0 MPa and a relative elongation of 250%. The resistivity before stretching is 0.01 ohmmeter, and after ten 20% stretchings the resistivity is 0.05 ohmmeter. After age hardening at 70° C. for 96 hours, the tensile strength variation was 5% and the relative elongation changed by 10%. After age hardening at a temperature of 100°C for 10 days, the resistivity before stretching is 0.01 ohmmeter, and the resistivity of the horn after 10 times of 20% stretching is 0.
,03 ohm meters.

After 7 years of storage under warehouse conditions with temperature variations from 0 to +35'C, the resistivity of the vulcanizate is 0.015 ohmmeter.

Example 2゜ Mixing was performed as in Example 1 above.

The mix consisted of divinyl rubber (65 parts by weight) and plasticized butadiene-nitrile rubber (35 parts by weight). Carbon is chemically combined with 0.18% boron, ωrr? /f
Carbon black (100 parts by weight) and graphite (15 parts by weight) having a specific adsorption surface area of
201J, Okibe) into the polymer matrix. The rubber mix has a plasticity of 0.24 and an extrusion rate of 1.2 f/cd. The optimum vulcanization at a temperature of 160°C is vulcanization. The vulcanizate has a tensile strength of 7 MPa, a relative elongation of 330%, and a resistivity of 0.007 ohm meddle before stretching, which resistivity decreases to 0.005 ohm after ten 20% stretching. It became 01 ohm meter. 96 hours, 7
After age hardening at a temperature of 0°C, the variation in tensile strength is 5
%, the variation in relative elongation rate is 10%. 10 at 100℃
After aging and hardening for days, the resistivity before stretching is 0.007.
It's Ohm Meadle.

After ten 20% enlargements it becomes 0.012 ohmmeter. After 7 years of storage in warehouse conditions at temperatures between 0 and +40°C, the vulcanizate resistivity is equal to 0.007 ohm meddle.

Example 3 Using a laboratory mill, 200 x 450 m polyvinyl chloride plasticized resin (100 parts by weight) is mixed with butadiene-nitrile rubber (21,3 parts by weight). Carbon is 0.3
Carbon black (87.5 parts by weight) which is chemically bonded with x amount % of boron and has a specific adsorption surface area of 100 m/f, stearic acid (0.34 parts by weight) and dibutyl sepatate (25 parts by weight). into the above mix.

This mixing is carried out for 10-12 minutes at a temperature of 175±15°C. The composition thus formed was cut into strips, granulated and compressed at a temperature of 180 ± 1°C to give 11M
Hold for 10 minutes under pressure of Pa, then 30-49℃
Cool to temperature. This composition was 0.02
It has a resistivity of 1 ohmmeter and after 10 times 20% stretching has a resistivity of 0.05 ohmmeter. The tensile stress at break is 6 MPa, the relative elongation is 150%, and the embrittlement temperature Fi is -40°C. After extrusion at a temperature range of 120-170°C, its resistivity is 0.07-Vo, 0.5 ohmmeter.

After heat aging hardening at (1)°C for (7) days and accelerated aging hardening simulating canopy storage for 3 years, the resistivity was 0.
．． It is within the range of 0.01 to 0.14 ohm meters.

Example 4 Using an experimental mill, low density polyethylene (100 parts by weight) was mixed with styrene/divinyl copolymer (100 parts by weight), syntanol (1 part by weight), and carbon at a temperature of 130 to 150°C. Black (85 parts by weight) (its carbon content is 0.
4% by weight of boron and has a specific adsorption surface area of 90/l). Mixing time is 15-17 minutes including web rolling. The produced composition is cut into strips and granulated. 4.5-5.
The plate, compressed at a temperature of VC 165-176°C under a specific pressure of 5 MPa and cooled to a temperature of 30-40°C, is compressed at a temperature of K 190°C under a load of 98 N. ]
It has a melt index of X 1O-3f/s. The tensile stress at break was 12.8 MPa.

The relative elongation at break is 536% and the resistivity is 0.4 ohmmeter.

Example 5 In a rubber mixer, ethylene-10 pyrene rubber (10
0 parts by weight) at a temperature of ~ω°C, and then treated with Ultax (L parts by weight), Neosyn D (0.5 parts by weight), zinc white (5 parts by weight), and stearic acid (3 parts by weight). , 3 equivalent parts of carbon black (120 parts by weight), the carbon of which is chemically combined with 0.5% by weight of boron, 110d
/f) and graphite (13 parts by weight) are introduced together with the plasticizer. This mixture was heated in a grinding roll for 10 minutes at a roll gap of 5 to 8011%.
Milling at a temperature of ~60°C followed by peroximone (4
, double i part) and cut the mix into rolls.

Mixing time is additive. The temperature is maintained in the range 60-100°C and the plasticity is 0.15. The plate is vulcanized at a temperature of 160° C. during curing. Swelling in % sulfuric acid and 20% caustic soda for 2,160 hours is zero.

A plate with a thickness of 0.25 mm has a resistivity of 0.004 ohmmeter.

Example 6 Plasticized butadiene-nitrile rubber (100 parts by weight) was mixed with stearic acid (2 parts by weight) in a rubber mixer.
Mixed with zinc white (6 parts by weight) and Neosyn D (1 part by weight), followed by 3 equal parts of carbon black (2 parts by weight).
40 parts by weight) (the carbon of which is chemically combined with 0.3% by weight of boron and has a specific adsorption surface area of 90 n?/f) and graphite (120 parts by weight) are introduced. The mixing time is 16 minutes and the temperature is maintained within the range of 70-130°C.

Prior to compression molding, peroximone is introduced into the rubber mix (rubber mix assistant fill, 9F). 1
Optimal vulcanization at a temperature of 80°C is 5 minutes. 0.25
The resistivity of a ~0.30+m thick grate is 0.000
It is a 6 ohm meddle.

Example 7 Using a 200 x 450 m experimental mill, 40'
At a temperature of C, carbon chemically bonds with 0.2% by weight of boron and 80n? Carbon black (100 parts by weight) and silicone rubber A (100 parts by weight) with a specific adsorption surface area of /l
Part L) and then peroximone F-40.
(8 parts by weight) is introduced. The mix is cured at a temperature of 150C. The vulcanizate has a tensile strength of 2.3 MPa, a relative elongation of 408%, and a
It has a resistivity of 5 ohms.

Claims (1)

[Claims] 1. Carbon black having carbon chemically bonded with 0.18 to 0.5% by weight of boron and having a specific adsorption surface area of 60 to 110 m^2/g in the following component proportions (parts by weight) An electrically conductive composition containing a polymer substrate and electrically conductive carbon black, characterized in that the polymer matrix contains 100 parts and 38 to 240 parts of electrically conductive carbon black. 2. As a polymer substrate, natural rubber, isoprene rubber, butadiene-nitrile rubber, ethylene-propylene rubber,
An electrically conductive composition according to claim 1, characterized in that it contains fluororubber, chloroprene rubber, urethane rubber, silicone rubber or a mixture thereof. 3. additionally 1 to 3 parts by weight of cross-linking agent and 5 to 4 parts by weight
A conductive composition according to claim 1 or 2, characterized in that it contains 0 parts by weight of a plasticizer. 4. The conductive composition according to claim 1, which contains a mixture of polyvinyl chloride plasticized resin and butadiene nitrile rubber in the following component proportions (parts by weight) as a polymer substrate. Polyvinyl chloride plasticized resin 80 to 90 Butadiene-nitrile rubber 10 to 20 Conductive carbon black 100 to 110 5. Contains polyethylene and styrene/divinyl copolymer in the following component proportions (parts by weight) as a polymer substrate An electrically conductive composition according to claim 1, characterized in that: Polyethylene 45-55 Styrene/divinyl copolymer 45-55 Conductive carbon black 38-45