JPH01272824A - Electrically conductive fiber and production thereof - Google Patents

Abstract

PURPOSE:To obtain the title fiber having excellent conductivity, abrasion resistance and endurance such as resistance to washing and suitable for an antistatic clothing and carpet, by subjecting a fiber to composite spinning with a solution of pyrrole and an oxidant used as a core component. CONSTITUTION:(A) Pyrrole and (B) an oxidant (e.g., iron chloride) are dissolved in (C) a solvent (e.g., dimethyl formamide) having >=900mV or <=400mV oxidation potential. (D) A fiber of polymethacrylate, etc., is subjected to composite spinning using the above-mentioned solution as a core component and then reaction is carried out by impregnating (E) a solvent (e.g., methanol or water) having 400-900mV oxidation potential into the resultant composite fiber and replacing the component C with the component E to provide the aimed fiber.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a conductive fiber in which polypyrrole is present inside the fiber and a method for producing the same. For more details,
The present invention relates to a conductive fiber with excellent durability such as abrasion resistance and washing resistance, and a method for producing the same.

(Conventional technology) Adding conductivity to fibers using conductive polymers is
Compared to conductive fibers in which ordinary conductive inorganic particles are mixed or attached to fibers, they have characteristics such as higher conductivity and easier production. In particular, when a polymer of pyrrole is used, it is attracting attention because it not only has high conductivity of 1q even without doping, but also has high stability.

However, when imparting conductivity to fibers using a conductive polymer, the method is to bring pyrrole into contact with a polymer containing an oxidizing agent (JP-A-63-20361, JP-A-63-42972). The method was limited to methods in which polypyrrole is produced on the electrode surface by electrolytic polymerization. That is, in all of them, polypyrrole was only attached to the surface layer of the polymer serving as the base material. Therefore, there was a problem that durability such as abrasion resistance and washing resistance was inferior.

Furthermore, in JP-A No. 61-282479, the surface layer of a fiber made of a synthetic polymer is impregnated with pyrrole, and an iodine solution is applied thereto to simultaneously replace the oxidized polymer of pyrrole with iodine, thereby producing polypyrrole even inside the fiber. A method is shown. However, in the fibers obtained using this method, most of the electrically conductive polypyrrole is only attached to the surface of the fibers, and the excess iodine attached to the grains is absorbed by the fibers and other substances with which they come into contact. There also occurred the problem that the characteristics deteriorated.

(Problems to be Solved by the Invention) The present invention solves the above problems and easily provides a conductive fiber having high conductivity and excellent durability such as abrasion resistance and washing resistance, and a method for manufacturing the same. This is what we provide.

(Means for Solving the Problems) In order to achieve the above object, the present invention has the following configuration.

(1) A conductive fiber characterized by containing polypyrrole inside the fiber.

(2) Pyrrole and oxidizing agent have an oxidation potential of 9oo
mv or more or 400 mv or less, composite spinning is performed using the solution as a core component, and then the oxidation potential of the solvent is set to 400 mv or more and 900 mv or less.
1. A method for producing conductive fibers, the method comprising producing polypyrrole inside the fibers by changing the conductive fibers to less than mv.

(3) The method for producing conductive fibers according to claim 2, wherein the spinning method is a wet method or a wet-dry method.

(4) The method for producing conductive fibers according to claim 2, wherein the oxidizing agent is ferric chloride.

(5) Oxidation potential is 900 mv or more or 400 mv or more
3. The method for producing conductive fibers according to claim 2, wherein the solvent having a molecular weight of less than mv is a mixed solvent containing dimethyl sulfoxide.

(6) Claim 2, wherein the fiber is polyacrylonitrile fiber.
A method for producing a conductive fiber as described in .

(7) Pyrrole and oxidizing agent have an oxidation potential of 900
A method for producing conductive fibers, which comprises simultaneously coexisting in a solvent with mv or more and 400 mv or less, performing dry spinning using the component as a core component, and then evaporating the solvent to generate polypyrrole inside the fiber. .

It is related to.

The present invention will be explained in detail below.

The conductive fiber in the present invention is made by coexisting pyrrole and an oxidizing agent as a homogeneous solution in a solvent in which polymerization of pyrrole does not proceed.
After the solution is made to exist inside the fiber, pyrrole is polymerized and polypyrrole having conductivity is made to exist inside the fiber, thereby obtaining 1q.

The conductive fiber of the present invention has high conductivity due to the polypyrrole contained inside the fiber. Furthermore, since polypyrrole exists inside the fiber, there is no detachment of polypyrrole, and it has excellent durability such as abrasion resistance and washing resistance.

The polypyrrole present inside the fiber may be ubiquitous in the center or a part of the cross section of the fiber, or may be uniformly distributed over the cross section. As long as most of the polypyrrole exists inside the fiber, there is no particular problem even if some of it is on the surface, but since polypyrrole is substantially continuous in the fiber axis direction, it provides electrical conductivity in the fiber length direction. preferred.

However, polypyrrole does not necessarily have to be continuous without cutting, and as long as the median length is several centimeters to several tens of centimeters, the conductivity as a whole is maintained.

The method for manufacturing the present conductive fiber will be explained below.

A feature of the present invention is that polypyrrole, which conventionally could only be applied to the fiber surface, is present inside the fiber. That is, in the past, the oxidizing agent and pyrrole were brought into contact for the first time at the stage of final polymerization of pyrrole, whereas in the present invention, the pyrrole and oxidizing agent are allowed to coexist in advance under conditions that do not allow polymerization to proceed. By making both of them exist inside the fiber and then polymerizing them, it was possible to make polypyrrole exist inside the fiber.

The oxidizing agent used in the present invention not only acts as a catalyst in polymerizing pyrrole, but also sometimes acts as a doping agent, and although there are no particular limitations, it is a preferable substance from the viewpoint of the polymerization rate of pyrrole. , various metal salts, especially metal chlorides. As specific examples, various substances such as iron chloride, tin chloride, zinc chloride, molybdenum chloride, antimony chloride, and aluminum chloride can be used, and ferric chloride is more preferable. Depending on the case, an oxidizing agent and a co-catalyst may be present together. Examples include manganese oxide, lead oxide, copper chloride, and the like. Furthermore, several types of metal chlorides may be used in combination, and additives may be added as necessary.

In the present invention, the conditions under which pyrrole and the above-mentioned oxidizing agent coexist and the polymerization of pyrrole does not proceed can be obtained by controlling the oxidation potential of a solvent that uniformly dissolves both. That is, the oxidation potential of the solvent is 900
If it is above mv or below 400 mv, polymerization will not proceed. Oxidation potential is 900mv or more or 400mv
Specific examples of the following solvents include, but are not limited to, dimethylformamide, dimethylacetamide, dimethylsulfoxide, benzene, acetone, acetonitrile, etc. Several types of solvents may be mixed as long as the above conditions are met. Of course, you can use it as well. For example, methanol alone has an oxidation potential of approximately 500mV, and when pyrrole and an oxidizing agent coexist, polymerization proceeds immediately. However, when a mixed solvent containing dimethyl sulfoxide in the same amount as methanol is added, polymerization does not proceed, and the polymerization does not proceed. I can do it. Dimethyl sulfoxide is a preferred solvent because it has good compatibility with other solvents and at the same time, the oxidation potential can be easily controlled by using it as one of the mixed solvents.

The oxidation potential of the solvent referred to in the present invention is determined by a conventional measuring method). For example, the reference electrode is a saturated calomel electrode (
SCE), measured using a three-electrode method using platinum as the working electrode.

A method of making a solution in which pyrrole and an oxidizing agent coexist exist inside the fiber is accomplished by ordinary composite spinning in which the solution is placed in the core component or the island component. There is no problem in adding a thickener to match the viscosity of the core component or island component and the sheath component or sea component as long as the oxidation potential does not change. It can also be achieved by blend spinning.

The fibers used in the present invention are not particularly limited, but synthetic fibers and regenerated fibers are preferable in order to use the above-mentioned spinning method.

Specifically, polyarylate, polymethacrylate, polymethylmethacrylate, polyethylene, polypropylene, polystyrene, polyacrylonitrile, polyvinyl chloride, polyvinylidene chloride, polyvinylidene fluoride, polyether, polyester, polyamide, polyimide,
Examples include synthetic fibers made from silicone, polyvinyl alcohol, polyvinylpyrrolidone, polyacrylamide, polysulfone, polyphenylene sulfide, polyurethane, polyacrylic acid, etc., and regenerated fibers made from cellulose, cellulose derivatives, etc.

In the present invention, in order to generate polypyrrole inside the fiber, it is necessary to change the oxidation potential of the coexisting solution of polypyrrole and an oxidizing agent present inside the fiber to conditions that allow the polymerization of polypyrrole to proceed. This is achieved by setting the oxidation potential to 400 mv or more and 900 mv or less. There are no particular restrictions on the method of changing the oxidation potential, and the method for changing the oxidation potential of the obtained fiber is 4.
A method is used in which the core component is gradually replaced with a solvent of 00 mv or more and 900 mv or less, for example. Specific examples of this solvent include lower alcohols such as methanol, ethanol, and propyl alcohol, pentanol, octatool, water, and ethylene glycol.

Water and lower alcohols are more preferred from the viewpoints of ease of handling and prompt polymerization of pyrrole.

At this time, the conditions for changing the oxidation potential are not particularly limited, and the reaction can proceed rapidly, for example, at room temperature. In the case of a mixed solvent, the oxidation potential can be changed by drying the resulting fiber and removing the specific solvent by evaporation.

When the spinning method is wet or dry-wet spinning, it is particularly preferable because the coagulation bath can be used to coagulate the fiber components and change the oxidation potential at the same time.

In other words, when coagulation is achieved by reducing the solubility of the polymer in the solvent, the coagulation liquid penetrates into the fibers, and at the same time the coagulation liquid also penetrates into the core component, reducing the oxidation potential of the solvent in the core component. It also changes the. At this time, the fibers are not yet dense, which has the advantage that the solvent can be exchanged smoothly, and the reaction takes place in a short time. moreover,
By proceeding with polymerization during the formation of filaments, there is no breakage of pyrrole, a good continuous state of polypyrrole is achieved, and there is also the advantage that high electrical conductivity can be obtained. Specific examples of fibers that can be made using this method include polyacrylonitrile fibers,
Examples include polyvinyl alcohol fiber, polyvinylpyrrolidone fiber, and polysulfone fiber. Polyacrylonitrile fibers that can be spun using dimethyl sulfoxide, which is preferred as a type of solvent for the core component, are particularly preferred fibers.

Polypyrrole polymerization can also proceed by simply removing the solvent used for the core component, which has an oxidation potential of 900 mv or more or 400 mv or less, by drying or the like. When the spinning method is dry spinning, it is more preferable because it is possible to cause the above-mentioned polymerization to occur at the same time as thread-like formation accompanying desolvation of the sheath component during a series of spinning steps. Specific examples of fibers that can be made using this method include polyacrylonitrile fibers, polyurethane fibers,
Examples include polyvinyl alcohol fiber.

In the present invention, especially when polypyrrole is formed in the center of the fiber, the color of the fiber is not dominated by the black color of the polypyrrole, and the original color of the fiber is hardly impaired. This is an improvement over the fact that conventionally, when polypyrrole was attached to the fiber surface, the fiber color was the black color of polypyrrole, which often limited its use.

Polypyrrole, which is a conductive polymer as used in the present invention, may contain its by-products. Furthermore, a derivative of polypyrrole may be used as long as it has conductivity.

Furthermore, it is of course possible to combine the conductive fibers obtained according to the present invention with other fibers to impart conductivity and antistatic properties as a whole.

The conductive fiber of the present invention is suitable for industrial fields such as clothing and carpets where static electricity is a problem and requires conductive properties, industrial fields that require conductivity, and applications where electromagnetic shielding is required such as computer fields. .

Hereinafter, the conductive fiber according to the present invention will be explained using Examples.

(Example) Example 1 3 parts of ferric chloride was added to 10 parts of methanol to make a homogeneous solution, and 5 parts of dimethyl sulfoxide was added.

The oxidation potential of the solution was measured using a saturated calomel electrode (SCE) as a reference electrode and platinum as a working electrode.
It was 0 mv. Next, 3 parts of pyrrole was added to the solution and allowed to coexist with ferric chloride, but the solution was transparent and brown, and no precipitate was observed.

The above solution was used as the core component, and a dimethyl sulfoxide solution in which 20% polyacrylonitrile was dissolved was used as the sheath component, and normal composite wet spinning was performed with 100 holes.

At this time, a mixed solvent of dimethyl sulfoxide/water = 1/3 was used as the coagulation bath, and the water was used for both coagulation and changing the oxidation potential. The residence time of the fibers in the coagulation bath is approximately 1
It was 0 seconds.

The spinning dope extruded into the coagulation bath quickly coagulates to form a filament, and the dimethyl sulfoxide contained in the core component replaces water in the coagulation bath, increasing the oxidation potential of the core component solution within a few seconds. Polymerization of pyrrole was carried out. This can be easily determined by the fact that the color of the formed thread is not white, but that the inside of the thread is colored.

The fibers were finally washed with water and stretched, and finally wound up at 20 m/min.

When the cross section of the obtained fiber was observed by SEM, it was found that the fiber surface was smooth with almost no deposits, and it was confirmed that polypyrrole was generated inside the fiber.

When the electrical resistance of the fiber was measured using the usual four-probe method, it was found that
It showed good conductivity of 7.6xlO1Ω·cm. Next, the fibers were washed for 15 minutes in a household electric washing machine using a commercially available powdered detergent, and then dehydrated for 5 minutes. After repeating this cycle three times, we measured the electrical resistance and found that 3
．． The conductivity was 0x102Ω◆cm, which was almost the same as that before treatment, and it was confirmed that there was no decrease.

Example 2 After adding 3 parts of ferric chloride to 10 parts of chloroform to make a homogeneous solution, the oxidation potential of the solution was measured in the same manner as in Example 1 and found to be 1200 mv. Next, 3 parts of pyrrole was added to the solution and allowed to coexist with ferric chloride, but the solution was transparent and brown, and no precipitate was observed.

Composite wet spinning was carried out in the same manner as in Example 1, except that the above solution was changed to the core component. At this time, a mixed solvent of dimethyl sulfoxide/ethanol = 1/3 was used as the coagulation bath.

The spinning dope extruded into the coagulation bath rapidly coagulated to form a filament, and the oxidation potential of the core component solution decreased and pyrrole polymerization occurred within a few seconds. This can be easily determined by the fact that the color of the formed thread is not white, but that the inside of the thread is colored.

The fibers were finally washed with water and stretched, and finally wound up at 20 m/min.

The cross section of the obtained fiber by SEM was the same as that obtained in Example 1, and it was confirmed that polypyrrole was generated inside the fiber.

When the electrical resistance of the fiber was measured using the usual four-probe method, it was found that
It showed good conductivity of 9.4×10 2 Ω·cm. Next, after carrying out the washing resistance test in Example 1, the electrical resistance was measured, and it was found that the conductivity was 2.8×10 3 Ω·cm, which was almost the same as before the treatment, and there was no decrease in conductivity.

Example 3 A 40% aqueous solution of commercially available polyvinyl alcohol was used as a sheath component,
The core component of Example 1 was used as the core component, and composite dry spinning was performed at a hole number of 20° and a spindle temperature of 75°C. At this time, conditions were used: the temperature of the drying cylinder was 120° C., and the winding speed was 300 m/min. In this example, in the thread that passed through the drying tube, the core component was also desolvated and polymerization of pyrrole proceeded rapidly.

This can be confirmed by the fact that the thread, which was transparent directly under the nozzle, turns slightly gray after passing through the drying tube.

When the electrical resistance of the fiber was measured by the four-terminal method,
It showed good conductivity of 5.7×10 3 Ω·cm.

Furthermore, after the same washing resistance test as in Example 1, the fibers exhibited excellent electrical conductivity of 7.0 x 10 3 Ω·cm, indicating that they were durable against friction and washing.

Comparative Example 1 A commercially available polyacrylonitrile fiber was impregnated with a 20% iron chloride aqueous solution, and then water was evaporated to obtain a polyacrylonitrile fiber with iron chloride adhered to the fiber surface.

The fibers were exposed to a height of 10 cm above the surface of the pyrrole liquid at a liquid temperature of 110 degrees Celsius to generate pyrrole vapor, and black polypyrrole was formed on the surface of the fibers in 5 seconds.

When the electrical resistance was measured in this state by a four-terminal method, it showed good electrical conductivity of 2.5×10 3 Ω·cm.

Then, when the fiber was subjected to the same washing resistance test as in Example 1, the polypyrrole that had formed and adhered to the fiber surface was detached from the fiber, and the electrical resistance was determined to be 7.0×10 8 Ω.
・A significant deterioration in conductivity was observed.

Comparative Example 2 After adding 3 parts of ferric chloride to 10 parts of methanol to form a homogeneous solution, the oxidation potential of the solution was measured in the same manner as in Example 1 and found to be 550 mv. Then,
When 3 parts of pyrrole was added to the solution and an attempt was made to use it as a spinning stock solution, a black precipitate formed immediately after the addition of pyrrole, making it impossible to use it as a spinning stock solution.

(Effects of the Invention) According to the present invention, fibers having high conductivity can be easily obtained. In particular, conductive fibers with excellent durability such as abrasion resistance and washing resistance can be easily obtained.

Claims (7)

[Claims] (1) A conductive fiber characterized by containing polypyrrole inside the fiber. (2) Pyrrole and oxidizing agent have an oxidation potential of 900
mv or more and 400 mv or less, composite spinning is performed using the solution as a core component, and then the oxidation potential of the solvent is 400 mv or more and 900 mv or less.
1. A method for producing conductive fibers, the method comprising producing polypyrrole inside the fibers by changing the polypyrrole to less than v. (3) The method for producing conductive fibers according to claim 2, wherein the spinning method is a wet method or a wet-dry method. (4) The method for producing conductive fibers according to claim 2, wherein the oxidizing agent is ferric chloride. (5) Oxidation potential is 900 mv or more or 400 mv or more
3. The method for producing conductive fibers according to claim 2, wherein the solvent having a molecular weight of less than mv is a mixed solvent containing dimethyl sulfoxide. (6) Claim 2, wherein the fiber is polyacrylonitrile fiber.
A method for producing a conductive fiber as described in . (7) The oxidation potential of pyrrole and oxidizing agent is 900 m
A method for producing conductive fibers, which comprises simultaneously coexisting in a solvent with a voltage of V or more and 400 mV or less, performing dry spinning using the component as a core component, and then evaporating the solvent to generate polypyrrole inside the fiber. .