JP2007277569A - Electrically conductive polyaniline composition and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing an electrically conductive polyaniline composition having excellent water resistance and a method for producing a film composed of the electrically conductive polyaniline composition. <P>SOLUTION: The method for the production of an electrically conductive polyaniline composition comprises the doping of a polyaniline composed of imino-p-phenylene structure unit expressed by formula (I) with a phenolsulfonic acid novolak resin while performing the chemical oxidation or electrolytic oxidation of the polyaniline. The invention further provides a method for the production of an electrically conductive polyaniline film by contacting a film of the polyaniline composed of imino-p-phenylene structure unit with an aqueous solution of a phenolsulfonic acid novolak resin in the presence of an oxidizing agent to effect the doping of the polyaniline with the novolak resin. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a conductive polyaniline composition excellent in water resistance and heat resistance and a method for producing the same.

  In recent years, conductive polyaniline compositions comprising polyaniline and a dopant have attracted attention and are used in various fields. For example, it is described that a film made of the above polyaniline conductive composition is used as a solid electrolyte membrane in an aluminum electrolytic capacitor or a tantalum electrolytic capacitor (see Patent Document 1). That is, it is described that an electrolytic capacitor having excellent frequency characteristics can be obtained by applying a polyaniline solution on a dielectric film, drying it to obtain a polyaniline film, and then doping it with protonic acid. . In addition to this, the polyaniline conductive composition has been studied for practical use in many fields such as an antistatic material, an electromagnetic shielding material, a magnetic recording medium, a film capacitor, and a battery.

  It has also been found that polyaniline has a markedly high heat resistance by appropriately selecting the dopant. For example, a polyaniline composition having an aliphatic monosulfonic acid having a carboxyl group as a dopant exhibits very high heat resistance, and even when left at 125 ° C. for 650 hours, the decrease in conductivity is 1/10 of the original value. (Refer to Patent Document 2).

  However, it has been conventionally pointed out that a conductive polyaniline composition is not necessarily sufficient in terms of heat resistance and water resistance, which is important from a practical viewpoint. Therefore, it has been proposed to use a polymer sulfonic acid as a dopant, and according to this, a conductive polyaniline composition having improved water resistance compared to the case of using a sulfonic acid which is a low molecular compound is obtained. It is already known that this can be done (see Patent Document 3).

For example, when polyvinyl sulfonic acid, which is a polymer sulfonic acid, is used as a dopant, the resulting polyaniline composition clearly has improved water resistance compared to the case where a low molecular weight sulfonic acid compound is used. When immersed in water for a long time, a certain degree of decrease in electrical conductivity is inevitable. The degree of the decrease in the conductivity becomes about 1/400 of the initial value after being immersed in water for 500 hours.
Japanese Patent Laid-Open No. 03-035516 Japanese Patent Laid-Open No. 10-036667 Japanese Patent Laid-Open No. 03-028229

  The present invention has been made in order to solve the above-described problems in a conductive polyaniline composition, and an object thereof is to provide a conductive polyaniline composition excellent in water resistance and heat resistance and a method for producing the same. .

  According to the invention, the formula (I)

A conductive polyaniline composition comprising: a polyaniline having an imino-p-phenylene structural unit represented by the formula: doped with at least one novolak resin selected from a phenolsulfonic acid novolak resin and a naphtholsulfonic acid novolak resin. Things are provided.

  Further, according to the present invention, while the polyaniline composed of the imino-p-phenylene structural unit represented by the above formula (I) is chemically oxidized or electrolytically oxidized, this is converted from a phenolsulfonic acid novolak resin and a naphtholsulfonic acid novolak resin. A method for producing a conductive polyaniline composition is provided, which comprises doping with at least one selected novolac resin.

  Further, according to the present invention, the polyaniline film comprising the imino-p-phenylene structural unit represented by the above formula (I) is selected from phenol sulfonic acid novolak resin and naphthol sulfonic acid novolak resin in the presence of an oxidizing agent. There is provided a method for producing a conductive polyaniline film, wherein an aqueous solution of at least one novolac resin is contacted and the polyaniline is doped with the novolac resin.

  According to the present invention, a conductive polyaniline composition obtained by doping a phenol sulfonic acid novolak resin or a naphthol sulfonic acid novolak resin into polyaniline in a reduced dedope state and a film thereof have excellent water resistance and heat resistance. In various fields, it can be suitably used as a conductive polymer material. In particular, the conductive polyaniline composition according to the present invention can be suitably used as a cathode material in, for example, an aluminum electrolytic capacitor or a tantalum electrolytic capacitor. In addition, an antistatic material, an electrode for organic electroluminescence, an electromagnetic shielding material, It can be suitably used as a material having water resistance and heat resistance in various applications such as foods.

  The conductive polyaniline composition according to the present invention has the formula (I)

The polyaniline which consists of an imino-p-phenylene structural unit represented by these is doped with at least 1 sort (s) of novolak resin chosen from a phenolsulfonic acid novolak resin and a naphtholsulfonic acid novolak resin. In accordance with the present invention, such a conductive polyaniline composition is obtained by chemically oxidizing or electrolytically oxidizing a polyaniline composed of an imino-p-phenylene structural unit represented by the above formula (I), with a phenolsulfonic acid novolak resin and It can be obtained by doping with at least one kind of novolak resin selected from naphtholsulfonic acid novolak resins.

  The polyaniline comprising the imino-p-phenylene structural unit represented by the above formula (I) is already known as described in JP-A-3-52929. An electrically doped polyaniline composition doped with an acid is produced, and is obtained by dedoping to form an oxidatively undoped polyaniline that is soluble in organic solvents, and then reducing the oxidatively undoped polyaniline. be able to.

  That is, reacting aniline with an oxidizing agent such as ammonium peroxodisulfate in an appropriate solvent in the presence of an appropriate proton acid, for example, sulfuric acid, for example, water or methanol, and collecting the precipitated powder by filtration. Thus, the conductive polyaniline composition doped with the protonic acid is obtained. This powder is then added to an aqueous solution of an alkaline material such as ammonia to neutralize (ie, dedope) the conductive polyaniline composition, thereby providing a general formula (IV)

(In the formula, m and n respectively represent the molar fractions of the quinonediimine structural unit and the phenylenediamine structural unit in the repeating unit, and 0 <m ≦ 1, 0 ≦ n <1, and m + n = 1.)
A polyaniline powder in an oxidatively dedoped state that is soluble in an organic solvent is obtained. Hereinafter, such a polyaniline is referred to as “oxidized and dedoped polyaniline”.

  Thus obtained polyaniline in the oxidatively dedoped state has a high molecular weight and is soluble in various organic solvents. Usually, the intrinsic viscosity [η] measured at 30 ° C. in N-methylpyrrolidone is 0.40 dL / g or more, for example, N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N— Dissolves in organic solvents such as dimethylformamide, dimethyl sulfoxide, 1,3-dimethyl-2-imidazolidinone, sulfolane. The solubility of the polyaniline in the dedope state in such an organic solvent depends on the average molecular weight and the solvent, but usually 0.5 to 100% of the polyaniline is dissolved to obtain a solution having a concentration of 1 to 30% by weight. be able to. In particular, this undoped polyaniline exhibits high solubility in N-methyl-2-pyrrolidone, and usually 20 to 100% of the polyaniline is dissolved to obtain a 3 to 30% by weight solution.

  Subsequently, if the quinonediimine structure of such an oxidatively dedoped polyaniline is completely reduced, as described in JP-A-3-52929, imino-p-phenylene represented by the above formula (I) Polyaniline composed of structural units can be obtained. Hereinafter, such a polyaniline is referred to as “reductive dedope polyaniline”.

  Such a reduced dedope polyaniline also usually has an intrinsic viscosity [η] measured at 30 ° C. in N-methylpyrrolidone of 0.40 dL / g or more, compared with the oxidatively dedope polyaniline. Furthermore, it is soluble in various organic solvents. For example, it dissolves better in solvents such as dimethylformamide, dimethylacetamide, dimethylsulfoxide, etc., compared to polyaniline in the oxidatively deoxidized state.

  As a reducing agent for reducing the polyaniline in the oxidatively dedoped state, reducing properties such as phenylhydrazine, hydrazine, hydrazine hydrate, hydrazine compounds such as hydrazine sulfate and hydrazine hydrochloride, lithium aluminum hydride, lithium borohydride, etc. A metal hydride compound or the like is preferably used. Since no residue is produced after the reduction reaction, hydrazine hydrate or phenylhydrazine is particularly preferably used as the reducing agent.

  The method for reducing the oxidatively dedoped polyaniline with the reducing agent is not particularly limited, and may be a normal reduction reaction method. For example, a method in which polyaniline in an oxidatively dedoped state is dissolved in an organic solvent such as N-methyl-2-pyrrolidone, and the above reducing agent is added to this solution. The reducing agent is N-methyl-2-pyrrolidone, dimethylformamide, dimethyl By dissolving in an organic solvent such as acetamide and adding the oxidatively dedoped polyaniline to this solution, by dispersing the oxidatively dedoped polyaniline in a non-solvent and performing a reduction reaction in a heterogeneous system, etc. Can do.

  The reduction reaction is usually performed in a solution containing 0.1 to 15% by weight, preferably 0.5 to 10% by weight of polyaniline in an oxidatively dedoped state. The reducing agent is usually used in an equivalent amount with respect to the amount of quinonediimine in the polyaniline in the oxidatively dedoped state, but an amount exceeding the equivalent can also be used in order to accelerate the progress of the reaction.

  However, when an excessive reducing agent is used in this way, if the resulting polyaniline in the reduced dedoped state is doped as it is in the solution state, an undesirable side reaction may occur, or the reduced dedoped state. When a polyaniline solution is stored for a long period of time, it may cause a decrease in molecular weight due to polymer chain cleavage. Therefore, when an excessive reducing agent is used, it is desirable to separate and purify the obtained polyaniline in a reduced and dedoped state by a reprecipitation method, and thereafter dope.

  The conductive polyaniline composition according to the present invention is obtained by doping such reduced dedope polyaniline with at least one kind of novolak resin selected from phenolsulfonic acid novolak resin and naphtholsulfonic acid novolak resin. According to the present invention, such a conductive polyaniline composition is obtained by oxidizing at least one kind of novolac resin selected from phenol sulfonic acid novolak resin and naphthol sulfonic acid novolak resin while oxidizing the polyaniline in the reduced and dedoped state. It can be obtained by doping.

  The phenolsulfonic acid novolak resin is preferably represented by the general formula (II)

(In the formula, R ₁ represents a hydrogen atom, an alkyl group, an alkoxyl group, a hydroxyl group, a carboxyl group, or an amino group.)
It is represented by Although not particularly limited, according to the present invention, among the phenolsulfonic acid novolak resins represented by the general formula (II), R ₁ is a hydrogen atom, and the substitution position of the sulfonic acid group is A p-phenolsulfonic acid novolak resin which is para to the hydroxyl group is preferably used.

  The naphtholsulfonic acid novolak resin is preferably represented by the general formula (III)

Wherein R ₂ and R ₃ each independently represent a hydrogen atom, an alkyl group, an alkoxyl group, a hydroxyl group, a carboxyl group or an amino group, and p and q are each independently an integer of 0, 1 or 2. (However, p and q are not 0 at the same time.)
It is represented by

  Although not particularly limited, according to the present invention, among the naphtholsulfonic acid novolak resins represented by the general formula (III), for example, 1-naphthol-4-sulfonic acid, 1-naphthol- 1-naphthol sulfonic acid such as 5-sulfonic acid, 1-naphthol-8-sulfonic acid, etc., 1 such as 1-naphthol-3,6-disulfonic acid, 1-naphthol-3,8-disulfonic acid, etc. -A naphthol disulfonic acid novolak resin is preferably used.

  In the present invention, the phenolsulfonic acid novolak resin and the naphtholsulfonic acid novolak resin each include an alkali metal salt, an ammonium salt, an organic amine salt, and the like. Examples of the alkali metal salt include a sodium salt and a potassium salt. Examples of the organic amine salt include a triethylamine salt, a triethanolamine salt, and an ethylenediamine salt, but are not limited thereto. Is not to be done.

  In the present invention, the phenol sulfonic acid novolak resin and the naphthol sulfonic acid novolak resin are not particularly limited in terms of their molecular weights, but are usually weight averages measured by GPC using sodium polystyrene sulfonate as a standard polymer. A molecular weight in the range of 2000 to 800000 is preferred. When the molecular weight of the phenolsulfonic acid novolak resin or naphtholsulfonic acid novolak resin is less than 2000, the resulting conductive polyaniline composition is not sufficiently improved in water resistance, while the phenolsulfonic acid novolak resin or naphtholsulfonic acid novolak When the molecular weight of the resin is larger than 800,000, as will be described later, the viscosity of the aqueous solution of the phenol sulfonic acid novolak resin or naphthol sulfonic acid novolak resin used for doping is too high and it is difficult to dope polyaniline.

  According to the present invention, in order to dope a phenol sulfonic acid novolak resin or a naphthol sulfonic acid novolak resin into polyaniline in a reduced and dedope state, it is preferable that the above-mentioned novolak resin is allowed to act on polyaniline in the presence of an oxidizing agent. Do. Further, instead of using an oxidizing agent, polyaniline can also be doped by allowing the novolak resin to act while electrolytically oxidizing polyaniline in a reduced and dedoped state using an electrode for electrolysis.

  In this specification, doping of polyaniline with a phenolsulfonic acid novolak resin or a naphtholsulfonic acid novolak resin while oxidizing polyaniline is referred to as “oxidation doping” in this specification. According to the present invention, a conductive polyaniline composition having the novolak resin as a dopant can be obtained by doping polyaniline very rapidly by performing such oxidative doping on polyaniline in a reduced and dedoped state. .

  In such oxidative doping, polyaniline is oxidized and one of the unshared electron pairs on the nitrogen atom is taken away, generating a positive charge on the nitrogen atom, and then this positive charge is present in the reaction system. Proton acid anion approaches and cancels the positive charge, thus maintaining electrical neutrality, whereby the nitrogen atom of polyaniline becomes a cation radical. Thus, polyaniline has the same semiquinone cation radical structure as described above and has conductivity.

  The oxidizing agent used for the above-mentioned oxidation doping is not particularly limited as long as it can oxidize polyaniline in a reduced dedope state. For example, ferric chloride, ferric perchlorate, oxalic acid Ferric salts such as ferric iron, cupric salts such as cupric chloride and cupric perchlorate, cuprous chloride (air oxidation), persulfates such as ammonium persulfate, potassium dichromate Such as dichromates such as potassium permanganate, iodates such as sodium iodate, chlorates such as sodium chlorate, hydrogen peroxide, manganese dioxide, cerium ammonium nitrate, lead oxide, A quinone-type oxidizing agent etc. can be mentioned. Specific examples of the quinone oxidant include p-benzoquinone, o-benzoquinone, p-toluquinone, 1,2-naphthoquinone, 1,4-naphthoquinone, diphenoquinone, chloranil, 2,3-dichloro-5,6-dicyano- Examples include p-benzoquinone, tetracyanoquinodimethane, sodium 1,2-naphthoquinone-4-sulfonate, sodium 1,4-naphthoquinone-2-sulfonate, tetrafluoro-p-benzoquinone, and the like.

  According to the present invention, it is not always necessary to oxidize all the imino-p-phenylene structural units of polyaniline during the oxidative doping of polyaniline in the reduced and dedoped state, so the amount of the oxidizing agent used is also particularly limited. Is not to be done. However, usually, the oxidizing agent is appropriately used from 1/10 equivalent to a large excess with respect to the imino-p-phenylene structural unit of polyaniline. The oxidizing agent is usually used as a solution having a concentration of 0.1 to 30% by weight, preferably as an aqueous solution. When the concentration of the oxidant is too small, it takes a long time for the oxidation doping of the polyaniline, whereas when the concentration of the oxidant is too large, the polyaniline molecular chain is broken during the oxidation doping of the polyaniline, This is because the polyaniline is deteriorated, for example, the molecular weight of the polyaniline is lowered.

  According to the present invention, the concentration of the aqueous solution of the phenolsulfonic acid novolak resin or naphtholsulfonic acid novolak resin to be used in the doping of the polyaniline in the reduced dedoped state is not particularly limited, and is usually 2-50. It is in the range of wt%.

  Doping of polyaniline in the reduction-dedoped state can also be performed at room temperature. However, doping under heating at 50 to 100 ° C. can shorten the time required for processing compared to doping at room temperature.

  The time required for doping is appropriately determined by measuring the conductivity of the polyaniline obtained, but is usually in the range of about 10 minutes to 10 hours. When the polyaniline powder in a reduced dedope state is added to an aqueous solution of a phenolsulfonic acid novolak resin or a naphtholsulfonic acid novolak resin and doped, the powder is initially light blue but becomes blackish green by doping.

  As described above, the polyaniline in the reduced dedope state is soluble in various organic solvents, so it is dissolved in an appropriate organic solvent, cast on an appropriate base material, cast at an appropriate temperature, For example, a film made of conductive polyaniline can be obtained by heating and drying to a temperature in the range of 50 to 150 ° C. to form a self-supporting film and oxidizing this film. For example, an aqueous solution containing a phenol sulfonic acid novolak resin or a naphthol sulfonic acid novolak resin together with an appropriate oxidizing agent is prepared as a doping treatment liquid, and the polyaniline film is immersed in this, or after the treatment liquid is applied to the film, If necessary, the conductive polyaniline film can be obtained by washing the film with an appropriate solvent.

As described above, when a film made of polyaniline in a reduced and dedope state is oxidatively doped, the film that was initially light blue changes to black-blue after doping. Accordingly, the conductivity of the film is about 10 ⁻¹⁰ S / cm before doping, but has a conductivity as high as 10 ⁰ to 10 ² S / cm after doping.

  In the conductive polyaniline composition thus obtained, the sulfonic acid ion derived from the phenolsulfonic acid novolak resin or naphtholsulfonic acid novolak resin as a dopant is usually 15 to 75% of the number of moles of aniline units in the polyaniline. Included in the range. According to the present invention, in the conductive polyaniline composition, 15 to 75% of all nitrogen atoms of polyaniline become cation radicals, and the same number of dopant-derived anions (sulfonate ions) are ionically bonded to the nitrogen atoms. ing. The conductivity of polyaniline is highest when 50 mol% of aniline units in the polymer are so doped.

  The conductive polyaniline composition and the film according to the present invention exhibit very high water resistance. Conventionally, conductive polyaniline compositions obtained by doping polyaniline with polyvinyl sulfonic acid are known to have relatively high water resistance. However, if they are immersed in distilled water for 500 hours, their conductivity is It decreases to about 1/400 of the initial value. In contrast, according to the present invention, a conductive polyaniline composition obtained by doping a polyaniline with a phenol sulfonic acid novolak resin or a naphthol sulfonic acid novolak resin has a reduced conductivity even when immersed in distilled water for 500 hours. Is within 1/10 of the initial value.

  The reason why the conductive polyaniline composition and the film thereof according to the present invention have such high water resistance is not necessarily clear, and the present invention is not limited by theory, but the phenol sulfonic acid novolak resin or The phenolic hydroxyl group of the naphthol sulfonic acid novolak resin is considered to suppress the elimination of the novolak resin as a dopant from the polyaniline, that is, the dedoping as a result of strengthening the interaction with the polyaniline.

  Furthermore, the conductive polyaniline composition and the film thereof according to the present invention are excellent in heat resistance, have a polyvinyl sulfonic acid as a dopant, and have been conventionally known as having relatively high heat resistance. It has almost the same heat resistance as the composition and its film.

  Hereinafter, the present invention will be described with reference to examples, but the present invention is not limited to these examples.

Reference example 1
(Production of conductive polyaniline composition by oxidative polymerization of aniline)
A 10 L separable flask equipped with a stirrer, a thermometer and a straight tube adapter was charged with 6000 g of distilled water, 360 mL of 36% hydrochloric acid and 400 g (4.295 mol) of aniline in this order to dissolve aniline. Separately, while cooling with ice water, 434 g (4.295 mol) of 97% concentrated sulfuric acid was added to 1493 g of distilled water in a beaker and mixed to prepare an aqueous sulfuric acid solution. This sulfuric acid aqueous solution was added to the separable flask, and the whole flask was cooled to −4 ° C. in a low-temperature thermostat. Next, 980 g (4.295 mol) of ammonium peroxodisulfate was added to 2293 g of distilled water in a beaker and dissolved to prepare an aqueous oxidizing agent solution.

  The whole flask was cooled in a low-temperature thermostatic bath, and while maintaining the temperature of the reaction mixture at −3 ° C. or lower, the aqueous solution of ammonium peroxodisulfate was transferred from the straight tube adapter to the acidic aqueous solution of aniline with stirring using a tubing pump. Was gradually added dropwise at a rate of 1 mL / min or less. Initially, the colorless and transparent solution turned from greenish blue to blackish green as the polymerization proceeded, and then a blackish green powder precipitated.

  A temperature rise is observed in the reaction mixture during the precipitation of the powder. Also in this case, in order to obtain a high molecular weight polyaniline according to the present invention, the temperature in the reaction system is 0 ° C. or lower, preferably −3 ° C. It is important to keep it below. After the powder deposition, the dropping rate of the ammonium peroxodisulfate aqueous solution may be slightly faster, for example, about 8 mL / min. However, also in this case, it is necessary to adjust the dropping rate so as to keep the temperature at −3 ° C. or lower while monitoring the temperature of the reaction mixture. Thus, after 7 hours were required and the dropwise addition of the ammonium peroxodisulfate aqueous solution was completed, stirring was continued for an additional hour at a temperature of −3 ° C. or lower.

  The obtained powder was separated by filtration, washed with water, washed with acetone, and vacuum dried at room temperature to obtain 430 g of a black-green conductive polyaniline composition powder. This was press-molded into a disk having a diameter of 13 mm and a thickness of 700 μm, and its conductivity was measured by the van der Pauw method. As a result, it was 14 S / cm.

(Production of polyaniline in an oxidatively dedoped state soluble in an organic solvent by dedoping of a conductive polyaniline composition)
350 g of the doped conductive polyaniline composition powder was added to 4 L of 2N ammonia water, and the mixture was stirred with an auto homomixer at a rotational speed of 5000 rpm for 5 hours. The mixture changed from black-green to blue-violet.

  The powder was separated by filtration with a Buchner funnel and washed repeatedly with distilled water until the filtrate became neutral while stirring in a beaker, and then washed with acetone until the filtrate became colorless. Thereafter, the powder was vacuum-dried at room temperature for 10 hours to obtain 280 g of a black-brown oxidatively dedoped polyaniline powder.

  The polyaniline in the oxidatively dedoped state was soluble in N-methyl-2-pyrrolidone, and the solubility was 8 g (7.4%) with respect to 100 g of the same solvent. The intrinsic viscosity [η] measured at 30 ° C. using this as a solvent was 1.23 dL / g. The polyaniline had a solubility of 1% or less in dimethyl sulfoxide and dimethylformamide. It did not substantially dissolve in tetrahydrofuran, pyridine, 80% aqueous acetic acid, 60% aqueous formic acid and acetonitrile.

  Furthermore, as a result of performing GPC measurement using the GPC column for N-methyl-2-pyrrolidone about the polyaniline in the oxidatively dedoped state, the number average molecular weight was 23,000 and the weight average molecular weight was 160000 (both in terms of polystyrene). there were

(Manufacture of polyaniline in reduced dedoped state)
2.5 g of the oxidatively dedoped polyaniline powder obtained as described above was added to 97.5 g of N-methyl-2-pyrrolidone and dissolved under stirring. To this solution, 0.82 g of phenylhydrazine was gradually added. At this time, the solution changed color from dark blue to light black brown, and at the same time, generation of nitrogen gas was confirmed.

  After completion of the reaction, the reaction mixture was dropped into 1.5 L of acetone substituted with nitrogen, and an off-white precipitate was obtained. The precipitate was filtered off with a glass filter, washed several times with nitrogen-substituted acetone, and then dried under reduced pressure at room temperature to obtain 2.3 g of reduced and undoped aniline consisting of imino-p-phenylene structural units. Obtained as an off-white powder. The intrinsic viscosity [η] measured at 30 ° C. in N-methyl-2-pyrrolidone of this polyaniline was 1.1 dL / g.

Example 1
10 g of the polyaniline powder in the reduced and dedope state obtained in Reference Example 1 was dissolved in 90 g of N-methyl-2-pyrrolidone to prepare a 10 wt% solution. A bank was made by stacking and sticking four 120 μm-thick polytetrafluoroethylene resin adhesive tapes on both ends of an A4 size glass plate, and the N-methyl-2-pyrrolidone solution of polyaniline was cast thereon. After squeezing with a glass rod, it was put into a hot air circulation dryer and dried at 80 ° C. for 1 hour. The polyaniline film thus obtained was peeled off from the glass plate. Four 1 cm square films were cut out from this film. The thickness of the film thus obtained was 38 μm.

  Using a p-phenolsulfonic acid novolak resin aqueous solution (manufactured by Konishi Chemical Industry Co., Ltd., polystyrene resin sulfonate standard GPC resin weight average molecular weight 20000), the solution was concentrated to an elutriated state using an evaporator. Ethanol was added thereto to adjust the solid content concentration to 20% by weight, and then p-benzoquinone was added and dissolved to prepare a 2.5% by weight solution as the benzoquinone concentration, which was used as a treatment solution for oxidation doping. .

  30 g of the doping treatment solution was placed in a 50 mL glass sample tube, and the four polyaniline films in the reduced and dedoped state were immersed in the glass tube and left at room temperature. After 30 minutes and 1 hour, two polyaniline films were taken out and washed with 30 mL of methanol three times to remove the phenolsulfonic acid novolak resin and the oxidizing agent p-benzoquinone adhering to the surface of the film. It dried for 30 minutes in the dryer of degreeC.

  The electric conductivity of each film thus obtained was measured by the van der Pauw method. The electrical conductivities of the two polyaniline films A and B subjected to the doping treatment for 30 minutes are 4.2 S / cm and 5.3 S / cm, respectively, and the two polyaniline films C and D subjected to the doping treatment for 1 hour are respectively The electrical conductivities of were 8.9 S / cm and 10.1 S / cm, respectively. Therefore, as a water resistance test, A and C were immersed in 15 mL of distilled water in a 20 mL capacity glass sample tube for 542 hours and then taken out and measured for conductivity. The conductivity of the film A subjected to the treatment for 30 minutes was 2.1 S / cm, and the conductivity of the film C subjected to the doping treatment for 1 hour was 8.2 S / cm.

  Next, as a heat resistance test, among the above four films, B and D were each attached to a 10 cm square glass plate in a cross shape with a 2 mm wide polytetrafluoroethylene resin adhesive tape, and a hot air circulating dryer at 125 ° C. It was taken in and taken out after 542 hours, and the conductivity was measured. The conductivity of the film C subjected to the doping treatment for 30 minutes was 1.1 S / cm, and the conductivity of the film D subjected to the doping treatment for 1 hour. Was 5.8 S / cm.

  Thus, after any water resistance test and heat resistance test, the conductivity of each film has hardly changed from the initial conductivity, and the conductive polyaniline film according to the present invention has high water resistance and heat resistance. It was shown to have

Comparative Example 1
Aldrich sodium polyvinyl sulfonate aqueous solution was ion-exchanged with a strongly acidic cation exchange resin Dowex W-50X12 (manufactured by Dow Chemical) to obtain a 20 wt% aqueous polyvinyl sulfonic acid solution in a free acid form.

  Except for using this polyvinyl sulfonic acid aqueous solution as a dopant solution, four conductive polyaniline films having polyvinyl sulfonic acid as a dopant were prepared in exactly the same manner as in Example 1. The conductivities of the two polyaniline films A and B subjected to the doping treatment for 30 minutes are 18.8 S / cm and 15.3 S / cm, respectively, and the conductivities of the films C and D subjected to the doping treatment for 1 hour are respectively 26.7 S / cm and 30.3 S / cm.

Therefore, as a water resistance test, out of the above four films, films A and C were immersed in 15 mL of distilled water in a 20 mL capacity glass sample tube for 542 hours and then taken out and the conductivity was measured. The conductivity of film A treated for 30 minutes was 4.4 × 10 ⁻² S / cm, and the conductivity of film C treated for 1 hour was 7.1 × 10 ⁻² S / cm. It was. Therefore, the electrical conductivity of the film after the water resistance test was about 1/400 of the initial electrical conductivity.

  In addition, as a heat resistance test, among the above four films, films B and D were attached to a cross with a 2 mm wide polytetrafluoroethylene resin adhesive tape on a 10 cm square glass plate, and hot air circulating drying at 125 ° C. It was put in the machine, taken out after 542 hours, and the conductivity was measured. The conductivity of film B subjected to doping treatment for 30 minutes was 1.2 S / cm, and the conductivity of film D subjected to doping treatment for 1 hour. Was 3.3 S / cm. Therefore, the electrical conductivity after the heat resistance test was about 1/10 of the initial electrical conductivity.

Example 2
In Example 1, instead of the phenolsulfonic acid novolak resin aqueous solution, 1-naphthol-4-sulfonic acid novolak resin (manufactured by Konishi Chemical Industry Co., Ltd., polystyrene polystyrene sulfonate standard resin weight average molecular weight 30000) 1-naphthol-4-sulfone in the same manner as in Example 1 except that 2,3-dichloro-5,6-dicyano-p-benzoquinone was used as the oxidizing agent instead of p-benzoquinone. Four conductive polyaniline films having an acid novolak resin as a dopant were obtained. When the conductivity of this conductive polyaniline film was measured by the van der Pauw method, the conductivity of the two polyaniline films A and B subjected to the doping treatment for 30 minutes were 1.2 S / cm and 2.2 S, respectively. The electric conductivities of the two polyaniline films C and D subjected to the doping treatment for 1 hour were 3.4 S / cm and 4.1 S / cm, respectively.

  Therefore, as a water resistance test, out of the above four films, the films A and C were each immersed in 15 mL of distilled water in a glass sample tube having a capacity of 20 mL for 508 hours, and then taken out and the conductivity was measured. The conductivity of film A subjected to the doping treatment for 30 minutes was 0.78 S / cm, and the conductivity of film C subjected to the doping treatment for 1 hour was 2.1 S / cm.

  Next, as a heat resistance test, among the above four films, films B and D were adhered to a cross with a 2 mm wide polytetrafluoroethylene resin adhesive tape on a 10 cm square glass plate, and hot air circulation at 125 ° C. When placed in a dryer and taken out after 508 hours and measured for conductivity, the conductivity of film B subjected to doping treatment for 30 minutes was 0.54 S / cm, and the conductivity of film D subjected to doping treatment for 1 hour. The degree was 2.8 S / cm.

  Thus, the conductive polyaniline film according to the present invention has high water resistance and heat resistance, with the conductivity almost unchanged from the initial value after both the water resistance test and the heat resistance test. It was shown that.

Claims (4)

Formula (I)

A process for producing a conductive polyaniline composition, which comprises doping a polyaniline composed of an imino-p-phenylene structural unit represented by formula (I) with a phenolsulfonic acid novolak resin while chemically oxidizing or electrolytically oxidizing the polyaniline. Phenolsulfonic acid novolak resin is represented by the general formula (II)

(In the formula, R ₁ represents a hydrogen atom, an alkyl group, an alkoxyl group, a hydroxyl group, a carboxyl group, or an amino group.)
The method for producing a conductive polyaniline composition according to claim 1, wherein Formula (I)

An aqueous solution of a phenolsulfonic acid novolak resin is brought into contact with a polyaniline film comprising an imino-p-phenylene structural unit represented by the following formula in the presence of an oxidizing agent, and the polyaniline is doped with the novolac resin: A method for producing a conductive polyaniline film. Phenolsulfonic acid novolak resin is represented by the general formula (II)

(In the formula, R ₁ represents a hydrogen atom, an alkyl group, an alkoxyl group, a hydroxyl group, a carboxyl group, or an amino group.)
The method for producing a conductive polyaniline film according to claim 3, wherein