JPH0571060B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a novel paint having high conductivity and a method for producing the same. Since this paint is dissolved in an organic solvent, molded articles of any shape can be obtained.

[Conventional technology]

As conductive polymer materials, those having a conjugated system formed by carbon-carbon bonds in the polymer skeleton are generally known. Examples include polyacetylene, polypyrrole, polyphenylene, polyphenylene vinylene, and the like. However, these conjugated polymers are rigid, insoluble and infusible, and cannot be molded into arbitrary shapes as they are.

In addition, as conductive polymer materials containing metals,
Conductive polymers with fillers made of metals such as silver are used. However, these are very expensive because they require the use of fine silver powder. For this reason,
Recently, fine powder of copper is replacing silver. However, since fine copper powder is oxidized in the air and copper oxide is produced, there is a problem in the stability of conductivity. Furthermore, conductive polymers with metal fillers require the addition of 70% by weight or more of metal in order to impart conductivity. This poses a problem in that not only the cost increases, but also the mechanical properties of the polymer itself deteriorate.

Furthermore, in addition to the above-mentioned filler containing metal, various polymers of complex compounds have been proposed as those containing metal.

For example, there is a polymer synthesized by the reaction of tetraethylammonium salt of tetrathiooxalate and copper acetate. (John R.Reynolds al,
(ACS) Poly.Prep., 25, No. 2241 (1984)). Since the polymer obtained by this method is also an insoluble and infusible powder like the conjugated polymer, it is impossible to mold it into any shape.

In addition, the polymer synthesized by this method uses tetraethylammonium salt of tetrathiooxalate, a unique raw material with a complex molecular structure [((C ₂ H ₄ ) ₄ N) ₂ C ₂ S ₄ ], as a monomer. Therefore, it is expensive and difficult to synthesize. Furthermore, the conductivity of the polymer obtained by this method does not improve even if it is doped.

[Problem that the invention seeks to solve]

As mentioned above, conjugated conductive polymers are insoluble,
Since it is infusible, it cannot be molded into any shape as it is.

Furthermore, conductive polymers containing metals such as silver or copper as fillers are very expensive or have problems with stability of conductivity due to oxidative deterioration. Furthermore, since it is necessary to add 70% by weight or more of metal to these materials, there is a problem that the mechanical properties of the polymer itself deteriorate.

Furthermore, polymers of complex compounds require unique raw materials with complex molecular structures, are expensive, and are not easy to synthesize. Furthermore, there is a problem that the polymer obtained by such a method is insoluble in a solvent, and its conductivity does not improve even if it is doped. Therefore, the present invention aims to obtain a paint that dissolves in a solvent by using inexpensive raw materials and a simple method of heating, and further, to obtain a paint that is stable in the air and has high conductivity. The purpose is to

[Means for solving problems]

In order to achieve the above object, the present invention consists of the following configuration.

(1) It is characterized by having carbon, sulfur, and copper as its main components, having an atomic ratio of 1.0:0.4 to 2.0:0.4 to 1.3, and being soluble in an organic solvent at 5% by weight or more. conductive paint.

(2) Carbon disulfide and copper halide in a dissolved state
The reaction is carried out at temperatures above ℃, and the main components are carbon, sulfur, and copper, and the composition ratio of each is expressed as an atomic ratio.
1.0:0.4 to 2.0:0.4 to 1.3, and a method for producing a conductive paint characterized by synthesizing a conductive paint having a property of being dissolved in an organic solvent at 5% by weight or more. The present invention uses carbon disulfide and copper halide, each of which are inexpensive monomers, and heats and reacts them at 60° C. or higher to combine a conductive polymer soluble in an organic solvent. It was also found that this paint has a high electrical conductivity of about 0.5 S/cm even without doping, and that the electrical conductivity is further improved by doping. The present invention relates to providing such a conductive paint which is composed of carbon, sulfur and copper atoms and which is soluble in an organic solvent. This method will be explained in detail below.

The conductive paint of the present invention is produced by heating and polymerizing carbon disulfide and copper halide in a suitable solvent at 60° C. or higher. Suitable solvents mentioned here include dimethylsulfoxide (DMSO), dimethylformamide (DMF), tetrahydrofuran (THF), and N-methyl-2-pyrrolidone (NMP).
It may be a polar solvent such as , or a non-polar solvent such as benzene or toluene, but preferably a polar solvent is used because the polymer is soluble in the polar solvent and the polymerization reaction tends to proceed smoothly. Further, the copper halides used in the present invention include cuprous chloride, cupric chloride, cuprous bromide, cupric bromide, cuprous iodide, etc.
Examples include copper, cupric iodide, cuprous fluoride, and cupric fluoride. Of course, a mixture of these may also be used. Among the above copper halides, cupric chloride, cupric bromide, and cupric iodide are preferred. Further, the hydrated salt of copper halide described above can be used as it is, but in order to proceed smoothly with the polymerization reaction, it is preferable to use one that has been heated (at 200° C. or higher) and dehydrated in a solvent in advance.

The polymerization temperature is 60°C or higher, but since the boiling point of carbon disulfide is as low as 46°C, it is necessary to conduct the polymerization under closed conditions to prevent carbon disulfide from escaping from the solvent.
Furthermore, if the polymerization temperature is too high, thermal decomposition of the paint will occur. Therefore, the polymerization temperature is preferably 60 to 200°C.

The concentrations of the monomers carbon disulfide and copper halide are not particularly limited, but are usually 0.1 to 10 mol/each.
used at a concentration of Although the concentration ratio of carbon disulfide and copper halide is not particularly limited, it is usually preferable to use copper halide in a molar ratio of about 1.0 to 1.5 to carbon disulfide. Of course, the reaction proceeds to a certain degree even at other concentration ratios.

There are no particular restrictions on the reaction time, but in order to achieve the object of the present invention with a high yield, it is preferably 6 hours or more, depending on the type of solvent or the reaction temperature. Particularly in the low temperature range, in order to increase the yield, it is necessary to lengthen the reaction time. During the reaction, it is preferable to stir as vigorously as possible, which is important for more uniformly dispersing the copper halide powder.

In the manner described above, a black powder paint soluble in a solvent can be obtained. This paint differs greatly from conventional conductive molecules in that it easily dissolves in polar organic solvents such as N-methyl-2-pyrrolidone (NMP) and dimethyl sulfoxide (DMSO). In particular, NMP is an easy-to-use solvent.

By using its property of being soluble in solvents, it can be applied, for example, to conductive paints and adhesives.

In the conductive paint of the present invention, the abundance ratio of carbon, copper, and sulfur is preferably 1.0:0.4 to 1.3:0.4 to 2.0 (carbon:copper:sulfur) in atomic ratio, respectively. This is because of its conductivity and solubility in solvents.

The conductive paint of the present invention preferably has a degree of conductivity of σ = 0.01 S/cm or more. This is to obtain the desired conductivity.

Furthermore, the electrical conductivity of this paint itself is as high as 0.5 S/cm, and doping improves the electrical conductivity by about four times. It is also different from conventional conductive polymers containing metals such as complex compounds in that the conductivity is improved by doping.

Doping methods include doping by exposing the paint to a dopant gas atmosphere, doping by immersing the paint in a dopant solution, electrochemical doping, and ion implantation. There is a method in which a dopant is mixed into a paint solution and then the paint is molded.

Since the paint body synthesized according to the present invention is a unique paint that dissolves in a polar solvent, it is possible to mix it into a paint solution. Polyacetylene, a conventionally known conductive polymer,
Polypyrrole, polythiophene, polyparaphenylene, or complexes containing metals are all infusible and insoluble, so doping by this method is impossible. This method of mixing a dopant into a paint solution has advantages over other doping methods in that the doping time can be shortened and the paint can be doped uniformly. Of course, it is possible to dope the coating material of the present invention by any other doping method.

Hereinafter, the present invention will be explained in more detail with reference to Examples.

〔Example〕

Example 1 20 ml of carbon disulfide, 57.5 g of anhydrous cupric chloride, and 30 ml of N-methyl- ² -pyrrolidone (NMP) as a solvent were placed in a 100 ml glass autoclave equipped with a stirrer (pressure resistance 10 Kg/cm 2 ). After purging with N ₂ , the reactor was sealed and reacted at a temperature of 150° C. (pressure of 5 Kg/cm ² ) for 6 hours with stirring. A reaction solution containing some blackish brown precipitate was obtained. After the reaction is completed, the temperature is lowered to room temperature, solids in the reaction solution are removed by filtration, and 100 ml of water is added to the solution to precipitate a precipitate. This precipitate was washed several times with water and then vacuum dried at room temperature for 6 hours to obtain 1.5 g of a blackish brown powder. The polymer is water, alcohol, acetone,
Insoluble in toluene etc., but NMP, DMSO,
Dissolved in a solvent such as DMF at a ratio of 10% by weight or more.

Elemental analysis of this polymer shows 9.6% carbon and copper.
54.3%, sulfur 35.0%, and chlorine, nitrogen, and hydrogen were below detection limits. In this way, the polymer is composed of carbon, copper, and sulfur, and the elemental composition ratio is
It was C1.00Cu1.06S1.36.

The conductivity of this polymer was measured (by press-molding the powder and measuring it as a pellet) and found that it was 0.5 S/cm at room temperature, and when it was brought into contact with iodine vapor under vacuum, it improved by about 4 times. Improved to 2.3S/cm.

In addition, the infrared spectrum of this polymer was analyzed using the KBr method.
As a result of measurement in the range of 400 to 4000 cm ^-1 , 1600 to
A spectrum showing absorption in the high wavenumber region of 4000 cm ^-1 was observed.

Example 2 Instead of NMP used as a solvent in Example 1
Using DMSO, we also adjusted the polymerization temperature to 80 °C (pressure
1.0 Kg/cm ² ), and carbon disulfide and cupric chloride were reacted for 6 hours in the same manner as in Example 1. A yellow-brown to black-brown reaction solution was obtained, which was washed and dried in the same manner as in Example 1 to obtain 0.8 g of a yellow-brown to black-brown powder.
I got r. As in Example 1, the powder was mixed with water,
Insoluble in alcohol, acetone, toluene, etc., soluble in DMSO, NMP, DMF. The elemental analysis results show that the atomic ratio of carbon: copper: sulfur is 1.0:0.78:
It was 0.71.

The conductivity of this polymer is also 0.3S/cm before doping, and when it is further doped with iodine,
Improved to 1.2S/cm. As for the measurement results of the IR spectrum using the KBr powder method, the same spectrum as in Example 1 was obtained.

Example 3 Second chloride used as copper halide in Example 1
Using 30g of cupric bromide instead of copper, the polymerization temperature was adjusted to
The temperature was raised from 150°C to 60°C (pressure 0.7 Kg/cm ² ), and carbon disulfide and cupric bromide were reacted for 16 hours in the same manner as in Example 1. A yellow-brown to black-brown reaction solution containing some precipitates was obtained. After the reaction was completed, the temperature was lowered to room temperature, and the mixture was washed and dried in the same manner as in Example 1 to obtain 1.6 gr of a dark brown powder. The powder is dissolved in DMSO, NMP and DMF as in Example 1. Further, when the polymer was subjected to elemental analysis, measurement of electrical conductivity, and measurement of infrared spectrum, the measurement results were almost the same as those shown in Example 1.

〔Effect of the invention〕

Conductive polymer materials are lighter and easier to process than conventional metal conductors, so they can be used as electromagnetic shielding plates, heating elements, resistive elements, wires, electrode plates, and other conductive materials in electronics. It has great potential to be used in various fields in the future, and is expected to become a promising industrial material in the future.

The present invention provides such a conductive polymer material as
This paper concerns the synthesis of paints using carbon disulfide and copper halide as starting materials. Since the starting materials are low-cost carbon disulfide and copper halide, it is expected that very low-cost conductive materials will become possible.

Since the paint synthesized according to the present invention is dissolved in an organic solvent, it can be molded into any shape by, for example, a cast molding method. Furthermore, the electrical conductivity of the paint synthesized according to the present invention is that of the conventional one,
For example, the polymer synthesized from the tetraethylammonium salt of tetrathiooxalate shows no effect of doping with _I2 , etc., whereas the polymer according to the present invention improves the conductivity by about 4 times by doping with iodine etc. It has the characteristic of being able to

Claims (1)

[Claims] 1 The main components are carbon, sulfur, and copper, and the composition ratio of each is 1.0:0.4 to 2.0:0.4 to 1.3 in atomic ratio,
A conductive paint characterized by being soluble in an organic solvent at 5% by weight or more. 2. The conductive paint according to claim 1, wherein the organic solvent is N-methyl-2-pyrrolidone. 3. The conductive paint according to claim 1, wherein the degree of conductivity is σ = 0.01 S/cm or more. 4 Carbon disulfide and copper halide are dissolved at 60°C.
The reaction is carried out under the above temperature conditions, and the main components are carbon, sulfur, and copper, and the atomic ratio of each is 1.0:0.4.
~2.0: 0.4~1.3 and 5% by weight in organic solvent
A method for producing a conductive paint, which comprises synthesizing a conductive paint having a property of dissolving in the above manner. 5 Copper halides include cuprous chloride, cupric chloride, cuprous bromide, cupric bromide, cuprous iodide, cupric iodide, cuprous fluoride, and cupric fluoride. 5. The method for producing a conductive paint according to claim 4, wherein the conductive paint is one or more selected from the following. 6. The method for producing a conductive paint according to claim 4, wherein the reaction is carried out under pressure or in a closed environment. 7 Carbon disulfide and copper halide are dissolved at 60°C.
Claim 4, characterized in that the polymer obtained by reacting at a temperature above is subjected to a doping treatment.
2. Method for producing a conductive paint as described in Section 1.