JPH0784705B2 - Method for producing electrically conductive polymer molding - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Field of Industrial Application> The present invention relates to a method for producing a conductive polymer molded article. More specifically, the present invention relates to a method for producing a conductive polymer molded product in which an organic conductive polymer is produced by chemical oxidative polymerization inside a highly oriented polymer molded product such as a fiber and a film which requires mechanical properties.

<Prior Art> It has been conventionally known that pyrrole, thiophene, aniline and their derivatives are chemically oxidized to form a polymer having good conductivity. However, since the electrically conductive polymer obtained by such a conventionally known method is in the form of powder, it must be molded into a shape more suitable for the purpose when used, but these polymers are generally insoluble and infusible. Therefore, there is a drawback that molding is extremely difficult.

It is also known to electrochemically oxidize and polymerize the pyrrole, thiophene, aniline and the like to form a film-like conductive polymer on the electrode plate. However, with this method, a film-like sheet having good conductivity can be obtained, but its mechanical properties are insufficient, and it is difficult to obtain a sheet having a form other than the film form, for example, a fibrous form. Was there. In order to improve such drawbacks, various methods have been proposed in which a polymer having good moldability and the above-mentioned conductive polymer are compounded. For example, a method in which an insulating film is formed on the electrode by a casting method, or a separately formed insulating film is adhered to the electrode, and then pyrrole is electrochemically oxidatively polymerized in an electrolytic cell Vol. 33 4844-84
5), A method of dispersing and molding a powdery conductive polymer obtained by chemical oxidative polymerization into a polymer having good moldability, and molding a polymer containing a chemical oxidizer with a conductive polymer. A method of bringing a low molecular weight compound forming a coalescence into contact with each other to form a conductive polymer in a molded article and the reverse method (JP-A-61-111336, JP-A-61-282479) and the like are available. Proposed.

However, none of these conventional methods for synthesizing a conductive polymer and a polymer having good moldability has serious drawbacks, and none of them is satisfactory. For example, in the method of oxidatively polymerizing pyrrole electrochemically by providing an insulating film on the electrode, although the mechanical properties are improved, the shape of the conductive polymer obtained is limited to a film shape and it is difficult to obtain a fibrous shape. However, if the thickness of the insulating film is too thick, the conductive polymer is hardly produced, and the operation is troublesome and requires a special device such as an electrode.

A method of molding and shaping a powdery polymer having electroconductivity in a polymer having good moldability is to disperse the electroconductive polymer in an amount of 25% by volume or more in order to exhibit electroconductivity. It is necessary to obtain a molded product having extremely poor moldability and extremely poor mechanical properties, and special measures such as composite spinning and film lamination are required to obtain a satisfactory molded product. It has drawbacks such as

According to the studies by the present inventors, various methods of bringing a monomer containing a conductive polymer into contact with a molded article containing a chemical oxidant also have various drawbacks. That is, a dry-wet method in which a chemical oxidant is added to a polymer molded product in advance (for example, a polymer is dissolved and the chemical oxidant is previously dissolved in a solution, and then spinning and film formation are performed by a dry spinning method, a casting method, or the like. ) Is an extremely poorly handleable solvent when it is applied to a polymer having good mechanical and chemical properties and widely used (for example, polyethylene terephthalate, polybutylene terephthalate, polycaprolactam, etc.), and The resulting molded product also had the drawback of being extremely inadequate in mechanical properties. The method of melt-molding after adding the chemical oxidant to the polymer is insufficient in the thermal stability of the chemical oxidant, the chemical oxidant is not sufficiently uniformly dispersed in the polymer, or during melt molding. Since the chemical oxidizing agent is sublimated and scattered, it has a drawback that stable melt molding is difficult. Further, the method of impregnating a molded article after melt molding with a chemical oxidant is insufficient in the mechanical performance of the finally obtained molded article although the conductivity is good when applied to a low orientation molded article, On the contrary, it was also found that when applied to a highly oriented molded product in order to satisfy mechanical properties, it is difficult to obtain sufficient conductivity. Further, even if the molded product having good conductivity obtained from the low orientation molded product is stretched,
After forming a conductive polymer in a molded article, the stretchability was extremely poor and it was not possible to obtain a stretch ratio capable of sufficiently improving the mechanical performance, or it was found that if stretched forcibly, the conductivity would completely disappear. .

In addition, a method of forming a conductive polymer inside the highly oriented molded product by contacting it with a chemical oxidant after previously impregnating the highly oriented molded product with a low molecular weight compound forming a conductive polymer is also a chemical oxidant. When chromic acid, ammonium persulfate, ferric chloride or the like is used as the material, a molded product having good conductivity cannot be obtained, and conductivity is improved only when iodine is used. However, even in this case, the durability of the conductivity obtained was insufficient, and there was a drawback that the conductivity was lowered when exposed to a hot alkaline aqueous solution or when dry heat treatment was performed.

In this way, by forming a conductive polymer in the fiber-forming polymer molded product, it is not possible to satisfy the sufficient conductivity at the time of practical use, durability stability and mechanical performance at the same time. Was the actual situation.

<Object of the Invention> The present invention eliminates the drawbacks of the conventional methods for producing a conductive molded article, is excellent in conductive performance and durability thereof, and is also a very good mechanical performance of a conductive polymer molded article. To provide a novel manufacturing method for producing

<Structure of the Invention> As a result of intensive studies to achieve such an object, the present inventors have found that the low orientation molded article after melt molding is impregnated with a chemical oxidant and is stretched and oriented almost in the same manner as the unimpregnated one. Although, the molded product thus obtained is highly oriented, when it is brought into contact with a monomer forming a conductive polymer, the conductive polymer is efficiently transferred to the inside of the highly oriented polymer molded product. The present invention has been discovered and has been reached.

That is, according to the present invention, a chemical oxidizer is absorbed in a melt-molded low orientation molded article having a P value of 0.35 or less, which is made of a fiber-forming polyester or polyamide, and then stretched to obtain a highly oriented molded article. After that, the molded product is contact-absorbed with a monomer to be a conductive polymer by oxidative polymerization,
A method for producing a conductive polymer molded article, which comprises producing a conductive polymer in the molded article.

The fiber-forming polyester or polyamide, which is the base material of the electroconductive polymer molded product of the present invention, has a molecular chain highly oriented and mechanical performance by being stretched after being molded into a desired shape by melt molding. May be any as long as it is extremely improved, and examples of the polyester include alkylene terephthalates such as polyethylene terephthalate, polybutylene terephthalate and polyhexamethylene terephthalate, polyethylene naphthalate,
Polyalkylene naphthalate such as polybutylene naphthalate, polyethyleneoxybenzoate and a small amount of copolymerization components thereof such as isophthalic acid, adipic acid, 5-
Examples of the polyester include copolymers of sodium sulfoisophthalic acid and polyethylene glycol, and examples of the polyamide include aliphatic polyamides such as polyhexamethylene adipamide, polytetramethylene adipamide, and polycaprolactam. You can Among these, polyester, particularly polyethylene terephthalate or polybutylene terephthalate is preferable from the viewpoint of electrical conductivity, thermal and mechanical performance of the finally obtained molded product.

In the present invention, it is necessary that the polymer is first melt-molded to obtain a molded product having a low degree of orientation. Here, the low degree of orientation depends on the type of polymer used,
The birefringence of the molded product is Δn, the unoriented undrawn yarn of 10 denier single yarn made of the polymer is broken at the glass transition temperature and
When the birefringence when stretched to 0.95 times is Δn _t (for example, polyethylene terephthalate Δn _t = 0.18, polybutylene terephthalate Δn _t = 0.16), the value of P expressed by the following equation is 0.35 P = Δn / Δn _t Refers to the following: In a molded product with an advanced degree of orientation in which the P value exceeds 0.35, at the stage of absorbing the chemical oxidant described later, the amount of the conductive material required to give the finally obtained molded product is increased. It is not preferable because the chemical oxidant cannot be absorbed, or the conditions for absorbing the chemical oxidant must be extremely severe. The shape of the molded article may be any shape as long as it can be stretched to improve the strength, elastic modulus, dimensional stability, etc. after absorbing the chemical oxidant, but it may be fibrous or film-like. In the case of a form in which it is used after being oriented at a uniform degree, the effect of the present invention is great, which is particularly preferable.

In the present invention, it is necessary to absorb the chemical oxidizer before the stretching treatment of the low orientation molded product, but the above-mentioned P value is
It is also possible to absorb the chemical oxidizer after partial stretching in the range of 0.35 or less, and then perform stretching again.

As the chemical oxidant used in the present invention, any one may be used as long as the redox potential under the condition of polymerizing the organic low-molecular compound forming the conductive polymer described later is larger than the oxidative polymerization initiation potential. Can be used. Examples of such chemical oxidants include (1) ferric chloride, ferric nitrate, ferric sulfate, ferric citrate, ferric phosphate, ferric perchlorate, potassium ferricyanide, and the like. Trivalent iron compounds (2) Hexavalent chromium compounds such as potassium dichromate and chromic anhydride (3) Manganese compounds such as potassium permanganate and sodium permanganate (4) Ammonium persulfate, sodium persulfate, permanganate Persulfate compounds such as potassium sulfate (5) Nitric acid, sulfurous acid, hydrogen peroxide solution, sodium hypochlorite, potassium hypochlorite, etc. can be mentioned, and they may be used alone or in combination of two or more. You may mix and use it. Among these chemical oxidants, the trivalent iron compound, especially ferric chloride, penetrates well into the molded product, so the conductivity of the finally obtained molded product is improved and the durability stability is also improved. Therefore, it is preferable.

It is considered that the chemical oxidant acts as an oxidant for forming the conductive polymer, and at the same time, acts as a dopant for improving the conductive performance of the conductive polymer. Iron is preferred.

The method of absorbing the chemical oxidant into the molded article having a low degree of orientation is not particularly limited, but the simplest method is, for example, dissolving the chemical oxidant in a suitable solvent, and forming the molded article in this solution. The method of immersing is mentioned. Here, the suitable solvent is a solvent that dissolves the chemical oxidant and does not substantially soak the shape of the polymer molded product, such as water, alcohols, esters, ketones, aromatic hydrocarbons, It may be appropriately selected from aliphatic hydrocarbons, organic acids, organic acid amides, ethers, organic nitro compounds, organic nitrile compounds and the like depending on the type of polymer and the type of chemical oxidant. Also, two or more of these may be mixed and used.

When polyethylene terephthalate is used as the polymer and ferric chloride is used as the chemical oxidant, acetone or tetrahydrofuran is used as a suitable solvent.

The conditions for absorbing the chemical oxidizer into the molded product vary depending on the type of polymer, the degree of orientation of the molded product, the shape of the molded product, the type of chemical oxidant, the type of solvent, etc. It can be easily absorbed by appropriately changing the concentration of the liquid, the processing temperature, the processing time and the like. Also, by appropriately selecting these conditions, it is possible to change the permeation state of the chemical oxidizer into the molded product, and the conductive polymer generated inside the finally obtained molded product is used as the surface layer of the molded product. It is possible to increase the number of parts, or to make it almost uniform throughout the molding.

After this treatment, it is preferable to wash with a solvent in order to remove the chemical oxidant adhering to the surface.

In the present invention, the mechanical properties of the molded product, a stretching treatment is performed to improve the dimensional stability, etc., and a conductive polymer-forming monomer is used to impart conductivity to the molded product described below. Must be done before contact. If a conductive polymer is formed before stretching, this polymer loses almost no stretchability, so that the molded product is cracked and loses electrical conductivity at all, or the molded product is broken during stretching, which is not preferable.

In order to stretch the molded product having absorbed the chemical oxidant, the molded product may be stretched in the direction of the fiber axis or in the case of a film, may be uniaxially or biaxially stretched. In order to sufficiently improve the mechanical performance of the finally obtained molded product, it is necessary to orient it to a high degree, and under the same conditions as when absorbing a chemical oxidant, a low orientation treated with a treatment liquid containing no chemical oxidant. When the molded product is stretched, the above-mentioned P value is at least 0.
It is necessary to perform the stretching treatment under the same conditions as those of 70 or more. The stretching temperature is usually preferably above the glass transition point of the polymer constituting the molded article and below the melting point, but when the decomposition temperature of the absorbed chemical oxidant is lower than the glass transition point of the polymer, or the glass transition point. When the chemical oxidant escapes from the inside of the molded article at a temperature close to, it may be stretched at a temperature below the glass transition point.

As the monomer that is oxidatively polymerized to form a conductive polymer, many monomers have been known so far, but any of them is preferably used in the present invention. Examples of such a monomer include pyrrole and its derivative, thiophene and its derivative, aniline and its derivative, and the like.

As pyrrole and thiophene derivatives, 2,5
Those having no substituent in the -position and those having no substituent in the para-position are used as the aniline derivative. Specific examples of the pyrrole derivative include N-methylpyrrole, N-ethylpyrrole, 3-methylpyrrole, 3,4-dimethylpyrrole and N-phenylpyrrole. Examples of the thiophene derivative include 3-methylthiophene and 3,4-dimethylthiophene, and 2,2′-bithiophene which is a dimer of thiophene is also preferably used. As anilines, N-methylaniline, N-ethylaniline, N-butylaniline, N-phenylaniline, o- and m-toluidine, o- and m-anisidine, o- and m-chloroaniline such as N- Aniline and its derivatives having substituents at the position, ortho and / or meta
Furthermore, these salts are mentioned. These may be used alone or in combination of two or more.

These monomers form a polymer by undergoing chemical oxidative polymerization, and at the same time become a conductive polymer by being doped with a chemical oxidant and coordinating anions. It is also possible to improve the conductivity or the stability by further adding a dopant or substituting the dopant to these conductive polymers.

The method of bringing such a monomer into contact with the stretched highly oriented molded product to form a conductive polymer in the molded product is not particularly limited. The monomer may be directly contacted without a solvent, or a suitable solvent such as water, alcohols, esters, ketones, aromatic hydrocarbons, aliphatic hydrocarbons, organic acids, ethers, It may be dissolved in an organic acid amide, an organic nitro compound, an organic nitrile compound or the like and brought into contact with it, or if the monomer can be gasified, its vapor may be brought into contact with it. Further, a dopant may be allowed to coexist for the purpose of improving the electric power of the obtained conductive polymer molded product.

Depending on the processing conditions for contacting the above monomers to form a conductive polymer, for example, the concentration of the monomer in the processing liquid, the processing temperature, the processing time, the type of the polymer used and the degree of orientation thereof. The distribution of the conductive polymer formed inside the molded article can be adjusted arbitrarily. That is, more conductive polymer can be produced in the surface layer portion of the molded product, and can be produced almost uniformly over the entire molded product.

The required amount of the conductive polymer to be formed in the molded product varies depending on the kind of the conductive polymer and the distribution state inside the molded product, but is usually 1 to 10 relative to the weight of the molded product.
It should be 0% by weight, preferably 3 to 50% by weight. If the amount of the conductive polymer formed is less than 1% by weight, sufficient conductivity cannot be obtained, while if it exceeds 100% by weight, the conductivity obtained reaches saturation and does not improve further, and conversely It is not preferable because it impairs the mechanical performance of the molded product obtained.

In addition, in order to adjust the amount of the conductive polymer to be generated, the amount of the above-mentioned chemical oxidant to be absorbed may be changed, or the conditions for contacting the monomer may be adjusted. It is preferable because it is easier to adjust.

In the present invention, it is desirable to perform heat treatment in order to improve the dimensional stability and mechanical performance of the molded product. The heat treatment may be performed after the stretching treatment, either before or after the contact with the monomer. Further, heat treatment conditions such as treatment temperature and treatment time can be arbitrarily selected as long as the chemical oxidizing agent used and the conductive polymer produced are in a stable range.

<Effects of the Invention> As described above, by forming a conductive polymer inside a conventionally highly oriented polyester or polyamide molded article,
It was difficult to impart good conductivity with good durability stability, but according to the production method of the present invention, it is extremely easy to produce an arbitrary amount of an electrically conductive polymer in an arbitrary distribution state. You can The molded product thus obtained has conductivity with good durability and stability and good mechanical properties, and can be applied to a wide range of applications such as conductive fibers, conductive films and conductive sheets.

Although the present invention has been described in detail above, the present invention includes the following aspects.

(1) The method for producing a conductive polymer molded product according to claim 1, wherein the low orientation molded product is made of a fiber-forming polyester.

(2) The method for producing a conductive polymer molded product according to claim 1, wherein the low orientation molded product comprises polyethylene terephthalate or polybutylene terephthalate.

(3) The method for producing a conductive polymer molded article according to the above-mentioned item (1) or (2), wherein the chemical oxidizing agent is a trivalent iron compound.

(4) The method for producing a molded electrically conductive polymer according to (3) above, wherein the chemical oxidizing agent is ferric chloride.

(5) The method for producing a conductive polymer molded product according to any one of the claims or (1) to (4), wherein the monomer that becomes a conductive polymer by oxidative polymerization is pyrrole.

<Examples> The present invention will be described in more detail with reference to the following examples. The following items in the examples are values obtained by measuring as follows.

Δn: Measured under a light source of Na-D ray (λ = 589 nm) using a polarization microscope.

Amount of conductive polymer produced: Determined by increasing the weight of the obtained conductive polymer molded product.

Electric resistance value: The resistance value per 10 fibers was calculated from the resistance value under a load of 1 KV.

Washing resistance: 1.0% by weight of nonionic household detergent Monogen Uni (manufactured by Procter & Gamble Far East) was used for stirring and washing at 50 ° C. for 40 minutes, and after washing with water for 5 minutes twice, the electrical resistance value was measured.

Hot water resistance: The electrical resistance value after immersion treatment for 60 minutes in hot water at 130 ° C was measured.

Dry heat resistance: The electric resistance value was measured after heat treatment for 60 seconds in a hot air dryer at 180 ° C.

Alkali resistance: 20 ° C with 5g / l sodium hydroxide aqueous solution
The electric resistance value after immersion treatment for 60 minutes at 120 ° C. or 120 minutes at 100 ° C. was measured.

Example 1 Polyethylene terephthalate having an intrinsic viscosity of 0.64 was used with a pore size of 0.
An unstretched yarn (Δn = 0.01 or less, P = 0.06 or less, single yarn 11 denier) was obtained by extruding from a die with 3 mm and 24 holes at 285 ° C. and winding at a speed of 1000 m / min. 1.0 g of this unstretched yarn is skein-wrapped and ferric chloride hexahydrate in acetone (weight ratio
1: 1) at room temperature for 24 hours, then washed with water and dried. Then, it was stretched 4 times at room temperature (Δn = 0.15 when stretched without impregnating ferric chloride, P = 0.83), and then allowed to stand in pyrrole vapor at room temperature for 24 hours. The obtained yarn was washed with water and then dried to obtain a treated yarn having a single yarn fineness of 3 denier. The weight increase of this treated yarn is 10% and the electric resistance is 1
It was × 10 ⁶ Ω / cm. The durability of washing resistance, hot water resistance, dry heat resistance and alkali resistance was also good as shown in Table 1.

Comparative Example 1 An undrawn yarn obtained in the same manner as in Example 1 was drawn 4 times or less at 70 ° C. to obtain a drawn yarn having a single yarn denier of about 2.8 denier. This drawn yarn was treated with an acetone solution of ferric chloride in the same manner as in Example 1, then washed with water and dried, then allowed to stand in pyrrole vapor and treated, and washed with water and dried. The treated yarn obtained was scarcely colored, and formation of a conductive polymer was not observed. Moreover, the electric resistance was 10 ¹⁰ Ω / cm or more, which was not conductive at all.

Comparative Example 2 The undrawn yarn impregnated with ferric chloride obtained in the same manner as in Example 1 was allowed to stand in pyrrole vapor at room temperature for 24 hours.
The weight increase of this treated yarn was 10% and the electric resistance was 10 ⁶ Ω / cm. However, the electric resistance of the drawn yarn obtained by drawing the obtained treated yarn 4 times was 10 ¹⁰ Ω / cm or more, and there was no conductivity at all.

Comparative Example 3 The same procedure as in Example 1 was repeated except that the ferric chloride-acetone solution treatment and the pyrrole vapor treatment were replaced with each other, and the undrawn yarn was treated with a pyrrole vapor treatment and the post-drawing treatment was a ferric chloride-acetone solution. I got a thread. The electric resistance of this treated yarn is 5.0 x 1
The conductivity was inferior to 0 ⁸ Ω / cm.

Examples 2, 3 and Comparative Examples 4, 5 The production amount of the conductive polymer was changed in the same manner as in Example 1 except that the conditions of treatment with the ferric chloride / acetone solution were changed as shown in Table 2. A treated yarn was obtained. The electric resistance value and yarn strength of these treated yarns are also shown in Table 2.

Example 5 A treated yarn was obtained in the same manner as in Example 1 except that the treated yarn was treated with the chemical oxidizing agent shown in Table 3. The results of weight increase and electric resistance of the obtained treated yarn are shown in Table 3.

Example 6 Polybutylene terephthalate having an intrinsic viscosity of 0.88 was extruded from the same die as used in Example 1 at 265 ° C. to obtain an undrawn yarn (Δn <0.01, P <0.06, single yarn 11 denier). The unstretched yarn was treated with ferric chloride, stretched 4 times and treated with pyrrole vapor as in Example 1. The electric resistance value of this treated yarn is shown in Table 4.

A treated yarn was obtained in the same manner as above, except that nylon-6 was used instead of polybutylene terephthalate and the spinning conditions were changed as shown in Table 4. The electric resistance value of this treated yarn is also shown in Table 4.

Example 7 A treated yarn was obtained in the same manner as in Example 1 except that the monomers listed in Table 5 were used in place of pyrrole as the monomer to be a conductive polymer by oxidative polymerization. Table 5 shows the weight increase and electric resistance of the treated yarn.

Comparative Example 6 An undrawn polyethylene terephthalate yarn obtained in the same manner as in Example 1 was drawn 4 times at 70 ° C. to obtain a drawn yarn having a single yarn denier of 2.8 denier.

1 g of the drawn yarn was skein-wound, immersed in a 70 ° C. aqueous solution in which 300 g of iodine and 300 g of potassium iodide were dissolved in 1 liter of water for 30 minutes, washed with water, and left overnight to dry. The yarn was treated by allowing it to stand in pyrrole vapor at room temperature for 24 hours, then washing with water,
Dried. The weight increase of this treated yarn was 4%, and the electric resistance value was 1.4 × 10 ⁶ Ω / cm, which was good. However, this treated yarn was inferior in dry heat resistance and alkali resistance as shown in Table 6.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display location // C08L 67:02 77:02 (56) References JP-A-61-111336 (JP, A) JP-A-61-282479 (JP, A) JP-A-49-81696 (JP, A)

Claims (1)

[Claims] 1. A chemical oxidizer is absorbed in a melt-formed low orientation molded article having a P value of 0.35 or less, which is made of a fiber-forming polyester or polyamide, and then stretched to obtain a highly oriented molded article. Thereafter, the molded product is contact-absorbed with a monomer to be a conductive polymer by oxidative polymerization, and a conductive polymer is produced in the molded product. Production method.