JP2909555B2 - Manufacturing method of electromagnetic wave shielding material - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an electromagnetic wave shielding material for preventing electromagnetic wave interference and taking measures against noise.

2. Description of the Related Art Conventionally, as a material or a method for forming an electromagnetic wave shielding material, conductive plastic, conductive paint, electroless plating, and the like are known. Conductive plastic is a material that contains stainless steel fiber, copper fiber, etc. as a conductive filler, and if it is used, molding into a required shape and shielding at the same time can be performed in a single step by a mold. It can be done, but because of the use of molds, the manufacturing cost is high,
In addition, applications are naturally limited. The method of performing electroless plating of a metal such as nickel on a base material and performing a shielding process on the base material can also be applied to a perforated article if the article has irregularities on the surface, and further has a thickness of 1 to 10. At 2 μm it gives conductivity comparable to metallic aluminum. However, the processing cost is even higher than the above-mentioned conductive plastic.

In contrast, shield processing using conductive paint
Although the range of applicable substrates is wide, on the other hand, such conductive paints usually include a filler of nickel powder or copper powder as a conductive component. , Difficult to apply. Also, from the manufacturing point of view, it is not easy to uniformly disperse the conductive filler as described above in the vehicle, and furthermore, if stored for a long period of time, the filler will settle out, The so-called pot life is short. When copper powder is used as the conductive filler, it is necessary to use an antioxidant in combination to prevent the oxidation.

On the other hand, in recent years, various high molecular organic polymers having conductivity by themselves have been known. For example, a method for producing a conductive organic polymer in which aniline is chemically oxidized and polymerized with a chemical oxidizing agent and contains an electrolyte ion as a topant and has a conductivity of 10 ^-6 S / cm or more is already known. Further, in the production of a conductive organic polymer by such chemical oxidative polymerization, an oxidizing agent having a standard electrode potential of 0.6 V or more, which is defined as an electromotive force in a reduction half-cell reaction based on a standard hydrogen electrode, is particularly preferably used. Has already been disclosed in
No. 258831.

However, in general, conductive organic polymers are insoluble and infusible, which is a major obstacle in developing any application. Therefore, conventionally, an intermediate which is soluble in an organic solvent is produced, and then, the intermediate is converted into a conductive polymer by physical or chemical means to develop its practical application. Various methods have been proposed. However, according to this method, treatment at a high temperature is required, or conversion of an intermediate to a conductive polymer does not always proceed as theoretically.

In the field of polypyrrole or polythiophene, polymers soluble in organic solvents are known. That is, thiophene having a long-chain alkyl group as a substituent or pyrrole having an alkanesulfonic acid group as a substituent is subjected to electrolytic oxidation polymerization to obtain an organic solvent-soluble poly (3-alkylthiophene) and a water-soluble polypyrrolealkanesulfonic acid, respectively. be able to. However, all of these methods use special monomers and subject them to electrolytic oxidation polymerization.
Manufacturing costs are significantly higher.

On the other hand, in the field of chemical oxidative polymerization of aniline, recently, about 1/4 mole amount of ammonium peroxodisulfate has been used as an oxidizing agent for aniline to chemically oxidize and polymerize aniline to form an organic solvent-soluble polyaniline. Is reported to be available (AG, MacDiarmid
et al., Synthetic Metals, 21 , 21 (1987); AGMacDiarm
id et al., L. Alcacer (ed), Conducting Polymers, 105
-120 (D. Reidel Publishing Co., 1987).

However, this polymer contains not only N-methyl-2-pyrrolidrin and dimethyl sulfoxide but also 80% acetic acid and 60%
Since it is also soluble in formic acid aqueous solution, its molecular weight is low.
It is also described that a self-supporting film can be obtained from a solution of a polymer such as N-methyl-2-pyrrolidone or dimethyl sulfoxide. Furthermore, it is described that a conductive polymer film doped with acetic acid can be obtained from an acetic acid solution, and this film is de-doped with ammonium. However, the undoped film has low strength due to the low molecular weight of polyaniline, and is easily broken by bending, so that it cannot be put to practical use.

It is also known that aniline can be oxidized with ammonium peroxodisulfate to obtain polyaniline soluble in tetrahydrofuran (J. Tang, Synthet).
ic Metals, 24, 231 (1988). However, this polymer is also considered to have a low molecular weight from the viewpoint of dissolving in tetrahydrofuran.

DISCLOSURE OF THE INVENTION The present inventors have made intensive studies to obtain a high molecular weight organic polymer soluble in organic solvents by chemical oxidative polymerization of aniline. Although it has a high molecular weight, in the undoped state,
A coating film that is soluble in various organic solvents can be easily obtained from the solution, and furthermore, by doping the coating film with prontoic acid, a tough high molecular weight highly conductive organic polymer coating can be obtained. The present inventors have found that a film can be obtained, and thus a high-performance electromagnetic wave shielding material can be obtained without using a conductive filler, and have led to the present invention.

Therefore, the present invention has been made in order to solve the above-mentioned problems in the conventional electromagnetic wave shielding material,
An object of the present invention is to provide a method for manufacturing an electromagnetic shielding material having high conductivity without including a conductive filler.

Means for Solving the Problems A method for producing an electromagnetic wave shielding material according to the present invention has a general formula (In the formula, m and n each represent a mole fraction of a quinone diimine structural unit and a phenylenediamine structural unit in the repeating unit, and are 0 <m <1, 0 <n <1, and m + n = 1). A polymer having as a repeating unit, an organic polymer that is soluble in an organic solvent in a undoped state is dissolved in the organic solvent, the obtained polymer composition is applied on a shield substrate, and dried, A thin film of polyaniline soluble in organic solvent was formed, and then the thin film was pKa value of 4.8.
It is characterized by doping with the following protonic acid.

In particular, in the present invention, the organic polymer that is soluble in the organic solvent in the undoped state, the skeleton vibration of the rose-substituted benzene in the laser Raman spectrum obtained by excitation with light having a wavelength of 457.9 nm, 1600cm Raman intensity of skeletal stretching vibration at higher wavenumber than ^-1
It is preferable that the ratio Ia / Ib of the Raman line intensity Ib of the skeleton stretching vibration having a lower wave number than Ia and 1600 cm ⁻¹ is 1.0 or more.

Furthermore, in the present invention, the organic polymer that is soluble in the organic solvent in the undoped state preferably has an intrinsic viscosity [η] measured at 30 ° C. in N-methylpyrrolidone of 0.40 dl / g or more. .

As described above, the electromagnetic wave shielding material according to the present invention has a predetermined repeating unit, and a conductive organic polymer obtained by doping a predetermined prontoic acid into an organic polymer that is soluble in an organic solvent in a undoped state. Preferably, the electromagnetic wave shielding material according to the present invention is a coating film.

According to the present invention, the electromagnetic wave shielding material according to the present invention as such a coating film has a predetermined repeating unit and forms a coating film of an organic polymer that is soluble in an organic solvent in an undoped state on a shield substrate. After that, it can be obtained by doping the coating film with a predetermined protonic acid.

First, an organic polymer having the above-described predetermined repeating unit and soluble in an organic solvent in a undoped state (hereinafter, referred to as an organic polymer)
There is an organic solvent-soluble polyaniline. ) Will be described.

The organic solvent-soluble polyaniline can be obtained by producing a conductive polyanine doped with a protonic acid present in the reaction system, and then dedoping the conductive polyaniline. This conductive polyaniline (hereinafter sometimes referred to as conductive polyaniline) is generally insoluble in organic solvents, unlike the above-mentioned solvent-soluble polyaniline.

The conductive polyaniline has a standard hydrogen electrode in an aniline in a solvent in the presence of a protonic acid having an acid dissociation constant pKa of 3.0 or less, while maintaining the temperature at 5 ° C or less, preferably 0 ° C or less. One mole of the oxidizing agent is required to reduce one molecule of the oxidizing agent per mole of aniline in an aqueous solution of the oxidizing agent having a standard electrode potential defined as an electromotive force in the reduction half-cell reaction as a reference of 0.6 V or more. Equivalent defined as the amount divided by the number of electrons, 2 or more equivalents, preferably 2
It can be obtained by gradually adding .about.2.5 equivalents.

Then, by dedoping the conductive polyanine with a basic substance, an organic solvent-soluble polyaniline can be obtained.

In the production of the conductive polyaniline by oxidative polymerization of aniline described above, as the oxidizing agent, hydrogen dioxide,
Ferric salt, iodate and the like are particularly preferably used. Among them, for example, ammonium peroxodisulfate and hydrogen peroxide usually have a range of 1 to 1.25 mol per 1 mol of aniline since two electrons per molecule are involved in the oxidation reaction. The amount is used.

The protonic acid used in the oxidative polymerization of aniline is not particularly limited as long as the acid dissociation constant pKa value is 3.0 or less, and examples thereof include hydrochloric acid, sulfuric acid, nitric acid, perchloric acid, hydrofluoric acid, and phosphoric acid. Inorganic acids such as hydrofluoric acid, hydrofluoric acid, hydroiodic acid, benzenesulfonic acid, p
-Aromatic sulfonic acids such as toluenesulfonic acid, methanesulfonic acid, alkanesulfonic acids such as ethanesulfonic acid,
Examples thereof include phenols such as picric acid, aromatic carboxylic acids such as m-nitrobenzoic acid, and aliphatic carboxylic acids such as dichloroacetic acid and malonic acid. Also, polymeric acids can be used. Examples of such a polymer acid include polystyrene sulfonic acid, polyvinyl sulfonic acid, polyallyl sulfonic acid, and polyvinyl sulfate.

The amount of protonic acid used depends on the mode of reaction of the oxidizing agent used. For example, in the case of manganese dioxide, the oxidation reaction is represented by MnO ₂ + 4H ⁺ + 2e ⁻ → Mn ²⁺ + 2H ₂ O.
It is necessary to use ptronic acid which can supply a double molar amount of protons. Also, in the case of hydrogen peroxide, the oxidation reaction is represented by H ₂ O ₂ + 2H ⁺ + 2e ⁻ → 2H ₂ O. Therefore, a proton acid capable of supplying at least twice the amount of protons of hydrogen peroxide to be used is used. There is a need. On the other hand, in the case of ammonium peroxodisulfate,
Since the oxidation reaction is represented by S ₂ O ₈ ²⁻ + 2e ⁻ → 2SO ₄ ²⁻ , it is not particularly necessary to use a protonic acid. However, in the present invention, even when ammonium peroxodisulfate is used as the oxidizing agent, it is preferable to use an equimolar amount of the protonic acid with the oxidizing agent.

As a solvent in the oxidative polymerization of aniline, a solvent which dissolves aniline, a protonic acid and an oxidizing agent and is not oxidized by the oxidizing agent is used. Water is most preferably used, however, if necessary, alcohols such as methanol and ethanol, nitriles such as acetonitrile, N-methyl-2-pyrrolidone, polar solvents such as dimethyl sulfoxide, ethers such as tetrahydrofuran,
Organic acids such as acetic acid can also be used. Also, a mixed solvent of these organic solvents and water can be used.

In order to dedope the obtained conductive polyaniline to obtain an organic solvent-soluble polyaniline, the temperature of the reaction mixture is always kept at 5 ° C during the oxidative polymerization of aniline described above, in particular, while adding the oxidizing agent solution to the aniline solution. It is important to keep it below ° C. Therefore, the oxidant solution should be added slowly to the aniline so that the temperature of the reaction mixture does not exceed 5 ° C. When the oxidizing agent is added rapidly, the temperature of the reaction mixture rises due to external cooling to produce a low molecular weight polymer, or a solvent insoluble conductive material can be obtained even after undoping as described later. Polyaniline is produced.

In particular, the reaction temperature is preferably kept at 0 ° C. or lower, so that after dedoping, N-methyl-2-
A high molecular weight organic solvent-soluble polyaniline having an intrinsic viscosity [η] of 1.0 dl / g or more measured in pyrrolidone at 30 ° C. (the same applies hereinafter) can be obtained.

Thus, a conductive polyaniline doped with the used protonic acid can be obtained. Thus, in the doped state, the resulting polyaniline forms a salt with the protonic acid present in the reaction system, so that, as is the case with many doped conductive organic polymers, generally, Does not dissolve in organic solvents as described below.

However, the conductive polyaniline which is doped with the above-mentioned protonic acid and is insoluble in the organic solvent can be made soluble in the organic solvent by undoping it.

During the production, the dedoping of the conductive polyaniline doped with the protonic acid present in the reaction system is a kind of neutralization reaction. May be neutralized with a basic substance. Such a basic substance,
Although not particularly limited, preferably, metal hydroxides such as aqueous ammonia, sodium hydroxide, potassium hydroxide, lithium hydroxide, magnesium hydroxide, and calcium hydroxide are used. In the dedoping, a basic substance may be directly added to the reaction mixture after the oxidative polymerization of the aniline, or a basic substance may be allowed to act on the conductive polyaniline once isolated.

The conductive polyaniline usually has a conductivity of 10 ⁻⁶ S / cm or more, and exhibits a blackish green color.
Purple or purple is copper color. This discoloration is because the amine nitrogen of the salt structure in the polymer was changed to a free amine. The conductivity is usually on the order of 10 ^-106 S / cm.

The undoped polyaniline thus obtained has a high molecular weight and is soluble in various organic solvents. Such organic solvents include N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-dimethylformamide, dimethylsulfoxide, 1,3-dimethyl-2-
Examples thereof include imidazolidinone and sulfolane. The solubility depends on the average molecular weight of the polymer and the solvent,
0.5-100% of the polymer dissolves, giving a 1-30% by weight solution.

In particular, the organic solvent-soluble polyaniline exhibits high solubility in N-methyl-2-pyrrolidone, and usually 20 to 100% of the polymer is dissolved, and a 3 to 30% by weight solution can be obtained. However, it does not dissolve in tetrahydrofuran, 80% acetic acid aqueous solution, 60% formic acid aqueous solution, acetonitrile and the like.

Therefore, when the organic solvent-soluble polyaniline is dissolved in an organic solvent to form a solution, the solution can be formed into a film by the squeezing method. For example, by casting an organic solvent-soluble polyaniline solution on a glass plate and then selecting the conditions for heating and drying the solvent, a uniform, tough, and highly flexible self-supporting film can be obtained.

Further, the film obtained by casting the polyaniline soluble in the organic solvent has different properties depending on the drying conditions of the solvent. Usually, intrinsic viscosity [η] is 0.40
Casting an N-methyl-2-pyrrolidone solution of an organic solvent-soluble polyaniline of dl / g or more on a glass plate and drying the solvent, when the drying temperature is 100 ° C or less, the obtained film is The strength is still not sufficiently high, and it is partially soluble in N-methyl-2-pyrrolidone. However, when the drying temperature is set to 130 ° C. or higher, the obtained film is excellent in flexibility, very tough, and does not crack even when bent. The film thus obtained does not dissolve in N-methyl-2-pyrrolidone and further does not dissolve in concentrated sulfuric acid. As described above, the solvent insolubilization of the polymer by drying the solvent at a high temperature after the casting is considered to be due to crosslinking of the polymer molecule due to the coupling of radicals existing in the polymer or generated upon heating. Can be

Therefore, of course, the organic solvent solution of the organic solvent-soluble polyaniline can be used as a coating composition.
If this coating composition is applied on a suitable substrate and dried,
An organic solvent-soluble polyaniline coating film that is uniform, tough, and excellent in flexibility can be obtained.

Therefore, in order to make the above-mentioned film and coating film tough and excellent in flexibility, it is desirable to use an organic solvent-soluble polyaniline having an intrinsic viscosity [η] of 0.40 dl / g or more.

The solution of the organic solvent-soluble polyaniline may be diluted with another organic solvent, if necessary. As such a diluting solvent, it is preferable to have compatibility with N-methyl-2-pyrrolidone. Accordingly, for example, a nitrogen-containing organic solvent containing an alcohol, a ketone, an ester, an ether, or a nitrile is preferably used. Can be

In particular, for example, aliphatic alcohols such as methanol, ethanol, propyl alcohol, and butyl alcohol are suitable as the diluting solvent. However, glycols such as ethylene glycol can also be suitably used. Acetonitrile and tetrahydrofuran are also suitable diluting solvents.

In addition, depending on the degree of dilution, as necessary, for example,
Hydrocarbon solvents that are not compatible with N-methyl-2-pyrrolidone, such as n-hexane, can also be used as the diluting solvent.

The organic solvent-soluble polyaniline, elemental analysis, infrared absorption spectrum, ESR spectrum, laser Raman spectrum, thermogravimetric analysis, solubility in solvents, from visible to near infrared absorption spectrum, (In the formula, m and n each represent a mole fraction of a quinone diimine structural unit and a phenylenediamine structural unit in the repeating unit, and are 0 <m <1, 0 <n <1, and m + n = 1). It is a polymer having a repeating unit.

Films obtained by solvent insolubilization from organic solvent-soluble polyaniline by the casting method also show substantially the same infrared absorption spectrum as the solvent-soluble polymer, and elemental analysis, infrared absorption spectrum, ESR spectrum, laser Raman spectrum , Thermogravimetric analysis, solubility in solvents,
From the visible to near-infrared absorption spectrum and the like, it is considered that the polymer has substantially the same repeating unit although it has a crosslinked structure.

In the organic solvent-soluble polyaniline represented by the above general formula, the values of m and n can be adjusted by oxidizing or reducing this organic solvent-soluble polyaniline. That is, by reducing, m is reduced,
n can be increased. Conversely, if oxidized, m can be increased and n can be reduced. When the quinonediimine structural unit in the polymer is reduced by the reduction of the polymer, the solubility of the polymer in a solvent is enhanced. Also, the viscosity of the solution is lower than before the reduction.

For the reduction of the organic solvent-soluble polyaniline, hydrazines such as hydrazine hydrate and phenylhydrazine, metal hydrides such as lithium aluminum hydride and lithium borohydride, and hydrogen are preferably used.
Phenylhydrazine is most preferably used because it dissolves in an organic solvent, particularly N-methyl-2-pyrrolidone, but does not reduce N-methyl-2-pyrrolidone. On the other hand, the oxidizing agent used for the oxidation of the solvent-soluble polymer is arbitrary as long as it can oxidize the phenylenediamine structural unit in the general formula, but in the reduction half-cell reaction based on the standard hydrogen electrode. An oxidizing agent having a standard electrode potential defined as an electromotive force of 0.3 V or more is particularly preferably used. For example, silver oxide which is a mild oxidizing agent is preferably used. Oxygen blowing is also useful. As a strong oxidizing agent, for example, potassium permanganate, potassium dichromate, or the like can be used, but it is necessary to prevent the polymer from deteriorating when used.

As described above, reducing the organic solvent-soluble polyaniline reduces the viscosity of the polymer solution, and is useful for keeping the solution stable.

As will be described later, if the organic solvent-soluble polyaniline is doped with a protonic acid, the conductive polyaniline can be obtained again.

In the reduction of the organic solvent-soluble polyaniline, when an excessive amount of a reducing agent is used, most of the quinone diimine structural units in the polymer are reduced, and thus the semiquinone radical (polaron) is formed by doping a quinone diimine structural unit with a protonic acid. Therefore, even if such a polymer is doped with a protonic acid, the conductivity of the obtained conductive organic polymer is not so high immediately after the doping. However, by leaving the doped polymer in the air, the enylenediamine structural unit to be reduced gradually returns to the quinonediimine structural unit by air oxidation, and the protonic acid remaining in the polymer layer is removed. As a result, a semi-quinone radical is generated, so that a highly conductive organic polymer can be obtained.

Surface resistance when used this way the conductive polyaniline obtained as a thin film differs by connexion proton acid used is usually from 15 ⁵ ~10 ¹⁰ Ω / □ extent.

Here, the characteristics of the organic solvent-soluble polyaniline obtained from the laser Raman spectrum will be described in comparison with conventionally known polyaniline.

In general, vibration spectroscopy is a means for obtaining information on vibrations between atoms constituting a substance, and includes infrared spectroscopy and Raman spectroscopy. Infrared spectroscopy is active in vibration modes that result in dipole moment changes, and Raman spectroscopy is active in vibrations that cause polarizability changes. Therefore, the two have a complementary relationship. In general, the vibration mode that appears strongly in infrared spectroscopy is weak in Raman spectroscopy, while the vibration mode that appears strongly in Raman spectroscopy is that in infrared spectroscopy. weak.

An infrared absorption spectrum is obtained by detecting energy absorption between vibrational levels, and a Raman spectrum is obtained when a molecule is excited by light irradiation and then falls to a higher vibrational level in the ground state. It is obtained by detecting the resulting scattered light (Raman scattering). At this time, the vibration energy level can be known from the energy difference of the scattered light with respect to the irradiation light.

Usually, a Raman spectrum is obtained by excitation with visible light from an argon laser or the like. Here, when the sample has an absorption band in the visible region, it is known that a very strong Raman ray can be obtained if the irradiation laser light and the absorption band wavelength match. This phenomenon is called the resonance Raman effect, and according to this, 10 ⁴ to 10 ⁵
Raman lines that are twice as strong can be obtained. According to the resonance Raman effect, information on the chemical structure excited by the wavelength of the irradiated laser light can be obtained with more enhanced information. Therefore, while changing the wavelength of the irradiated laser light,
By measuring the Raman spectrum, the chemical structure of the sample can be analyzed more accurately. Such a feature is a feature of Raman spectroscopy that does not exist in infrared spectroscopy.

FIG. 1 shows the solubility of N-methyl-2 in an organic solvent.
The intrinsic viscosity [η] measured at 30 ° C. in pyrrolidone is 1.2 d
4 is a laser Raman spectrum obtained by irradiating a sample of a l / g undoped polyaniline powder in a disk shape at an excitation wavelength of 457.9 nm. The assignment of the Raman line is as follows. 1622 and 591 cm ^-1 are skeleton stretching vibrations of para-substituted benzene, 1489 and 1479 cm ^-1 are
C = C and C = N stretching vibration of quinone diimine structure, 12
20cm ^-1 is a mixture of CN stretching vibration and CC stretching vibration, 1185
And 1165 cm ^-1 are the in-plane angular vibrations of CH.

FIG. 2 shows Y. Furukaws et al., Synth. Met., 16 , 189 (1
986) is a laser Raman spectrum obtained by irradiating the undoped polyaniline shown in 986) at an excitation wavelength of 457.9 nm. This polyaniline is placed on a platinum electrode,
It is obtained by electrolytic oxidation polymerization of aniline.

As shown in FIG. 1, in the solvent-soluble undoped polyaniline used in the present invention, the Raman line intensity Ia of the skeleton stretching vibration appearing at a higher wavenumber than 1600 cm ⁻¹ among the skeleton vibrations of the para-substituted benzene, The ratio Ia / Ib to the Raman line intensity Ib that appears at a wave number lower than 1600 cm ⁻¹ is 1.0 or more. On the other hand, in the conventionally known polyaniline including the polyaniline shown in FIG. 2, the ratio Ia / Ib is smaller than 1.0, including those by chemical oxidative polymerization.

The Raman lines at 1622 and 1591 cm ^-1 are both based on the skeleton stretching vibration of para-substituted benzene. In the polyaniline in the reduced state, a Raman line is generated only at 1621 cm ⁻¹ because it does not have a quinone diimine structure.However, in the undoped polyaniline having a quinone diimine structure, the Raman lines of 1622 and 1591 cm ⁻¹ are used as described above. A line appears. These Maran lines show oscillation wavelength dependence as shown in FIG.

As the excitation wavelength is changed from 488.0 nm to 4765.5 nm to 457.9 nm on the shorter wavelength side, Ia / Ib changes. That is, at 488.0 nm, Ia / Ib is smaller than 1.0, but 457.9 nm.
Is 1.0 or more, compared to 488.0 nm,
Ia / Ib intensity is reversed. This reversal phenomenon will be explained as follows.

FIG. 4 shows an electronic spectrum of the solvent-soluble polyaniline used in the present invention. Since the peak at 647 nm disappears by reducing polyaniline, it is considered to be derived from the quinone diimine structure, and the peak at 334 nm increases in intensity by reducing polyaniline. It seems to be derived from the π-π ^* transition. FIG. 4 shows the Raman excitation wavelength described above. Here, the band of para-substituted benzene skeleton stretching vibration, changing a vibration wavelength from 488.0nm to 457.9nm to the short wavelength side, as compared with the band of 1591cm ^-1, resonance Raman effect of the band of 1622cm ^-1 It is considered that the resonance condition becomes more advantageous, and the relative intensity changes as described above occur.

Next, in the spectra shown in FIG. 1 and FIG.
Despite the relative intensities of the Raman lines 91cm ^-1 and 1622cm ^-1 are the same excitation wavelength (457.9 nm), different from,
It will be explained as follows. That is, N, N'-diphenyl-p- as a model compound having a phenylenediamine structure
Phenylenediamine has a Raman line only at 1617 cm- ¹ ,
N, N'-diphenyl-p-benzoquinonediimine as a model compound of the quinonediimine structure was 1568 cm ^-1 and 16
Since it has a Raman line at 21 cm ⁻¹ , as shown in (a) below, a quinone diimine structure and a non-conjugated para-substituted benzene ring have a Raman line at 1622 cm ⁻¹ whose intensity has been increased by excitation of short wavelength light. And as shown in (b) below, the para-substituted benzene ring conjugated to the quinone diimine structure is 1591 cm ⁻¹
And a Raman line of 1622 cm ^-1 .

N, N'-diphenyl-p-phenylenediamine N, N'-diphenyl-p-benzoquinonediimine From the results of elemental analysis, in the undoped organic solvent-soluble polyaniline used in the present invention, the number of quinone diimines and the number of phenylenediamines are considered to be almost equal, so the structural chain of the undoped organic solvent-soluble polyaniline is , From the linkage between the quinone diimine structure and the phenylenediamine structure, as shown in (c), an alternating copolymeric chain of the quinone diimine structure and the phenylenediamine structure, and as shown in (d), the quinone diimine structure and the phenylenediamine structure. It is classified into two types of block copolymer-like chains having a nitrenediamine structure. In the figure, a para-substituted benzene ring indicated by an arrow indicates a quinone diimine and a non-conjugated benzene ring, and in the alternate copolymer-like chain, for example,
There are two per octamer chain unit, and in the block copolymeric chain, for example, 3 per octamer chain unit.
One. When the length of the chain unit is long, the difference between the numbers of the quinone diimine and the non-conjugated benzene ring in both cases is further increased. It can be said that this difference appears as a difference in the relative intensity of the Raman line between 1591 cm ^-1 and 1622 cm ^-1 .

In the organic solvent-soluble polyaniline used in the present invention, Ia / Ib in laser Raman spectrum
Since the ratio is 1.0 or more, it is considered that the quinone diimine structure contains a large number of non-conjugated benzene rings, and thus has the block copolymer-like chain.

The organic solvent solubility of the polyaniline used in the present invention is reasonably explained by having such a block copolymeric chain. Generally, it is known that an imine nitrogen (-N =) in a quinone diimine structure forms a hydrogen bond with a nearby secondary amino group hydrogen (-NH-) (Macromolecules, 21 , 1297 (1988)). The hydrogen bonds between the secondary amino groups are not strong.

Therefore, when the polyaniline has the alternating copolymeric chain, a network having a strong hydrogen bond as shown in (f) is formed. The insolubility of the conventionally known polyaniline in many organic solvents even in the undoped state is considered to be due to the formation of such a network having strong hydrogen bonds. On the other hand, when the polymer chain is the block copolymer chain as in the case of the soluble soluble polyaniline in the undoped state according to the present invention,
Usually, since the block chains have different lengths, (e)
As can be seen, even if the phenylenediamine structure portion and the quinonediimine structure portion are adjacent to each other, many hydrogen bonds cannot be formed, and the solvent penetrates between the polymer chains to form a bond with the solvent. It will be dissolved in an organic solvent. If the block chains had exactly the same length in all parts, they would form a network of hydrogen bonds as described above, but the probability of having such a structure is extremely small and is usually ignored. I can do it.

Further, such an interchain interaction is also explained from the CH-in-plane bending vibration of the laser Raman spectrum. The Raman line at 1162 cm ^-1 attributed to the C-H in-plane bending vibration of the undoped polyaniline shown in FIG. 2 shows that the polyaniline is reduced and all imine nitrogen is converted to secondary amino nitrogen. Then, the wave number shifts to 1181 cm ^-1 .

As described above, the solvent-soluble polyaniline used in the present invention has two Raman lines, 1165 and 1185 cm ⁻¹ , which are attributed to the CH in-plane bending vibration in the undoped state. The 1185 cm ^-1 Raman line is not found in the conventionally known undoped polyaniline, is not found in the reduced polyaniline, and has a C-value in the reduced state. It shows a value close to 1181 cm ^-1 attributed to the in-plane bending vibration.

From these points, it is considered that the solvent-soluble polyaniline used in the present invention has a block copolymer chain in an undoped state and has an atmosphere of a reduced structure. This means that despite the high molecular weight,
It will have high solubility in organic solvents. As described above, in the electromagnetic wave shielding material according to the present invention,
Polyaniline used as a conductive component is a novel polymer having a structural chain different from conventionally known polyaniline.

As described above, the oxidized aniline polymer used in the present invention has a quinonediimine structural unit and a phenylenediamine structural unit in a block copolymer-like chain as described above as a repeating unit. In this state, it is described as having conductivity by an acid-base reaction without a redox reaction. This conductive mechanism is called AGMacDiarmid et a
l., J. Chem. Soc., Chem. Commun., 1987 , 1784), doping with a protonic acid causes the quinone diimine structure to become protonated, as shown below, which forms a semiquinone cation radical structure. , Having conductivity. Such a state is called a polaron state.

As described above, polyaniline which is solvent-soluble in the undoped state is dissolved in an organic solvent, applied to an appropriate substrate, and dried to give a tough coating film. Such a coating film can easily be made into a conductive coating film by doping it with a protonic acid.

Here, as a preferred protonic acid, an acid dissociation constant pKa
In addition to organic acids having a value of 4.8 or less, hydrofluoric acid,
Examples thereof include hydrofluoric acid and perchloric acid.

Organic acids having an acid dissociation constant pKa value of 4.8 or less include aliphatic, aromatic, araliphatic, alicyclic and other mono- or polybasic acids, and further, such organic acids include hydroxyl groups, halogens, and the like. ,
It may have a nitro group, a cyano group, an amino group and the like.
Accordingly, specific examples of such organic acids include, for example, acetic acid,
n-butyric acid, pentadecafluorooctanoic acid, pentafluoroacetic acid, trifluoroacetic acid, trichloroacetic acid, dichloroacetic acid, monofluoroacetic acid, monobromoacetic acid, monochloroacetic acid, cyanoacetic acid, acetylacetic acid, nitroacetic acid, triphenylacetic acid, formic acid, oxalic acid Benzoic acid, m-bromobenzoic acid, p-chlorobenzoic acid, m-chlorobenzoic acid,
p-chlorobenzoic acid, o-nitrobenzoic acid, 2,4-dinitrobenzoic acid, 3,5-dinitrobenzoic acid, picric acid,
o-chlorobenzoic acid, p-nitronebenzoic acid, m-nitrobenzoic acid, trimethylbenzoic acid, p-cyanobenzoic acid, m-cyanobenzoic acid, thymol blue, salicylic acid, 5-aminosalicylic acid, o-methoxybenzoic acid, 1,
6-dinitro-4-chlorophenol, 2,6-dinitrophenol, 2,4-dinitrophenol, p-oxybenzoic acid, bromophenol blue, mandelic acid, phthalic acid, isophthalic acid, maleic acid, fumaric acid, malonic acid ,
Tartaric acid, citric acid, lactic acid, succinic acid, α-alanine, β
-Alanine, glycine, glycolic acid, thioglycolic acid, ethylenediamine-N, N'-diacetic acid, ethylenediamine-N, N, N ', N'-tetraacetic acid and the like.

The organic acid may have a sulfonic acid or a sulfuric acid group. Such organic acids include, for example,
Aminonaphtholsulfonic acid, metanilic acid, sulfanilic acid, allylsulfonic acid, lauric acid, xylenesulfonic acid, chlorobenzenesulfonic acid, 1-propanesulfonic acid, 1-butanesulfonic acid, 1-hexanesulfonic acid, 1-heptanesulfonic acid, 1-octanesulfonic acid, 1-nonanesulfonic acid, 1-decanesulfonic acid, 1
-Dodecanesulfonic acid, benzenesulfonic acid, styrenesulfonic acid, p-toluenesulfonic acid, naphthalenesulfonic acid and the like.

Further, the organic acid may be a polymeric acid. Examples of such a polymer acid include polyvinyl sulfonic acid, polyvinyl sulfate, polystyrene sulfonic acid, sulfonated styrene-butadiene copolymer, polyallyl sulfonic acid, polymethallyl sulfonic acid, and poly-2-acrylamido-2-methyl. Examples thereof include propanesulfonic acid and polyhalogenated acrylic acid.

A fluorine-containing polymer known as Naphion (registered trademark of DuPont, USA) is also suitably used as the polymer acid.

Before doping, the coating film has a reflected light color of copper and a transmitted light color of blue, but after doping with a protonic acid, the reflected light has a blue color and the transmitted light has a green color. After doping, the reflectance in the near infrared region (1000 to 2000 nm) changes significantly. That is, before doping, near-infrared light is almost reflected, but after doping, near-infrared light is almost absorbed.

The conductivity of the conductive coating obtained by doping is
Depending on the pKa value of the protonic acid used, p
Prontoic acid having a Ka value of 1 to 4.8 or less is effective. When a protonic acid having a pKa value of 1 to 4.8 is used, the smaller the pKa value, that is, the stronger the acidity, the higher the conductivity of the obtained coating film. However, when the pKa value is less than 1,
The conductivity of the film obtained is no longer changed and is almost constant. However, of course, if necessary, the pKa value is 1
The following proton acids may be used.

This conductive coating is also tough and does not break easily when bent. However, this conductive coating is doped with a protonic acid, like the conductive polymer prepared in the presence of prontoic acid. It does not dissolve in the above-mentioned organic solvent due to crosslinking by coupling of radicals generated in the step of heating and evaporating the solvent.

The electromagnetic wave shielding material according to the present invention is applied with a solution of the organic solvent-soluble polyaniline as described above on the surface of a substrate having a shielding process, dried, and formed into a coating film.
This coating is formed by doping the coating with a protonic acid as described above and considering the conductivity of the coating.

As the organic solvent, as described above, N-methyl-2-pyrrolidone, N, N-dimethylacetamide, N, N-
Dimethylformamide, dimethylsulfoxide, 1,3-
Dimethyl-2-imidazolidinone, sulfolane and the like can be mentioned. Further, such a solution of the organic polymer may be diluted with another organic solvent, if necessary. As such a diluting solvent, N-methyl-2-
Those having compatibility with pyrrolidone are preferred, and
For example, nitrogen-containing organic solvents including alcohols, ketones, esters, ethers, and nitriles can be exemplified.

In particular, for example, aliphatic alcohols such as methanol, ethanol, propyl alcohol, and butyl alcohol are suitable as the diluting solvent. However, glycols such as ethylene glycol can also be suitably used. Acetonitrile and tetrahydrofuran are also suitable diluting solvents.

In the present invention, a polymer acid is particularly preferred as the protonic acid. For example, to dope a coating of an organic solvent-soluble polyaniline in a undoped state with polystyrenesulfonic acid or polyvinylsulfonic acid, usually,
The polyaniline coating film may be immersed in an aqueous solution of polyvinyl sulfonic acid for polystyrene sulfonic acid having a pH of 2 or less. The time required for doping depends on the thickness of the polyaniline coating film to be used and the concentration of the aqueous solution of polystyrene sulfonic acid or polyvinyl sulfonic acid, but may be generally several tens of seconds to several days. In order to shorten the doping time, it is preferable to use an aqueous solution having a pH of 1 or less. Further, in general, if polystyrene sulfonic acid or polyvinyl sulfonic acid having a low degree of polymerization is used, doping can be performed quickly. On the other hand, if polystyrene sulfonic acid or polyvinyl sulfonic acid having a high degree of polymerization is used, a conductive polyaniline coating film in which dedoping hardly occurs can be obtained.

As described above, the conductive polyaniline coating film using polystyrene sulfonic acid or polyvinyl sulfonic acid as a dopant is weakly acidic, neutral, or an alkaline aqueous solution, or in a basic organic solvent, since it is difficult to release the dopant, Even when in contact with water or organic solvents, the conductivity does not change,
Thus, the shielding effect can be maintained irrespective of fluctuations in the conditions of the periodic environment such as humidity and moisture.

Further, for example, after doping the polyaniline coating with polystyrene sulfonic acid or polyvinyl sulfonic acid,
After thorough washing, other protonic acids, for example,
Since a conductive coating film containing no low-molecular acid as a dopant as described above can be obtained, such a conductive coating film may be mixed with a conductive polyaniline as a dopant by a low-molecular acid that may be partially mixed as a dopant. There is no danger of corrosion of parts.

Further, according to the present invention, the thickness of the polyaniline coating film can be arbitrarily adjusted, and the kind and the doping amount of the dopant can be adjusted. Therefore, the conductivity of the coating film can be freely adjusted by selecting the thickness of the coating film and the doping conditions. For example, according to the present invention, a film thickness of 0.01 to 2.00 on the shield substrate
μm can be formed, and as described above, if such a coating is doped with a protonic acid having a pKa value of 4.8 or less, 10 ^{−6 to} 30 S / cm, preferably 10 ⁻² to 10 S / cm. cm can be given.

As described above, the electromagnetic wave shielding material according to the present invention is obtained by applying a solution containing an organic solvent-soluble polyaniline in a undoped state on a shield substrate and drying it to form an organic solvent-soluble polyaniline coating film. Doping the coating of the organic solvent-soluble polyaniline in the undoped state,
It is obtained by imparting conductivity.

Therefore, the coating film is uniform and smooth, and as described above, even when it comes into contact with moisture, moisture, an organic solvent, or the like, the conductivity does not change, so that a stable electromagnetic wave shielding effect can be maintained. .

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

Example 1 (Manufacture of Doped Conductive Organic Polymer by Oxidative Polymerization of Aniline) 600 g of distilled water and 360 ml of 36% hydrochloric acid were placed in a 10-liter separable flask equipped with a stirrer, a thermometer, and a straight tube adapter.
And 400 g (4.295 mol) of aniline were charged in this order to dissolve aniline. Separately, 434 g of 97% concentrated sulfuric acid (4.295 g) was added to 1493 g of distilled water in a beaker while cooling with permanent water.
Mol) were added and mixed to prepare an aqueous sulfuric acid solution. This aqueous sulfuric acid solution was added to the separable flask, and the entire flask was cooled to −4 ° C. in a low-temperature constant temperature bath.

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 oxidizing agent aqueous solution.

The entire flask was cooled in a low-temperature constant temperature bath, and while maintaining the temperature of the reaction mixture at −3 ° C. or lower, the ammonium peroxodisulfate was added to the acidic aqueous solution of the aniline salt from a straight pipe adapter using a tubing pump while stirring. Aqueous solution
The solution was gradually dropped at a rate of 1 ml / min or less. Initially, the colorless and transparent solution turned from green-blue to black-green as the polymerization proceeded, and then a black-green powder was deposited.

During the powder deposition, an increase in temperature is observed in the reaction mixture. In this case, too, in order to obtain a high-molecular-weight polymer according to the present invention, the temperature in the reaction system must be 0 ° C. or lower, preferably −3 ° C. It is important to keep the temperature below ℃. After the powder deposition, the dropping rate of the aqueous solution of ammonium peroxodisulfate may be slightly increased, for example, to about 8 ml / min. However, also in this case, it is necessary to adjust the dropping speed so as to keep the temperature at −3 ° C. or lower while monitoring the temperature of the reaction mixture. After completion of the dropwise addition of the aqueous solution of ammonium peroxodisulfate over a period of 7 hours, stirring was continued for a further 1 hour at a temperature of -3C or lower.

The obtained polymer 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 polymer powder. This was pressed into a disk having a diameter of 13 mm and a thickness of 700 μm, and its electric conductivity was measured by the Van der Pauw method. As a result, it was 14 S / cm.

(Dedoping of conductive organic polymer with ammonium) 350 g of the doped conductive organic polymer powder was added to 2N
The mixture was added to 4 liters of ammonium water, and stirred at 5,000 rpm for 5 hours with an auto homomixer. The mixture turned from black green to bluish purple.

The powder was filtered off with a Buchner funnel and washed repeatedly with distilled water while stirring in a beaker until the filtrate became neutral, 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 undoped polymer powder.

This polymer was soluble in N-methyl-2-pyrrolidone, and the solubility was 8 g (7.4%) per 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 polymer had a solubility of less than 1% in dimethylsulfoxide and dimethylformamide. It did not substantially dissolve in tetrahydrofuran, pyridine, 80% acetic acid solution, 60% aqueous formic acid solution and acetonitrile.

FIG. 1 shows a laser Raman spectrum obtained by irradiating the undoped polyaniline powder into a disk-shaped sample at an excitation wavelength of 457.9 nm. For comparison, Y. Furukawa et al., Synth. Met., 16 , 189 (198
For the undoped polyaniline shown in 6),
FIG. 2 shows a laser Raman spectrum obtained by irradiation at an excitation wavelength of 457.9 nm. This polyaniline is obtained by electrolytic oxidation polymerization of aniline on a platinum electrode.

Also, by changing the wavelength of the laser excitation light,
FIG. 3 shows the results of measuring the Raman spectrum in the range of 00 cm ⁻¹ . Excitation wavelength from 488.0nm to 476.5nm
As the wavelength was changed to the shorter wavelength side to 457.9 nm, Ia / Ib changed.At 457.9 nm, it was 1.0 or more, indicating that the Ia / Ib intensity was reversed compared to 488.0 nm. It is.

 FIG. 4 shows an electronic spectrum.

Next, regarding the above-mentioned organic solvent-soluble polyaniline,
GPC using a GPC column for methyl-2-pyrrolidone
Measurements were taken. As the column, three kinds of columns for N-methyl-2-pyrrolidone were used in combination. Also, the eluent
A 0.01 mol / l concentration of lithium bromide in N-methyl-2-pyrrolidone was used. FIG. 5 shows the results of the GPC measurement.

From this result, the organic solvent-soluble polyaniline is:
The number average molecular weight was 23,000 and the weight average molecular weight was 160,000 (both in terms of polystyrene).

Similarly, N-methyl-2-
Organic solvent-soluble polyanilines having different intrinsic viscosities [η] measured at 30 ° C. in pyrrolidone were obtained. For these,
Table 1 shows the intrinsic viscosity [η] and the number average molecular weight and weight average molecular weight determined by GPC.

Example 2 (Preparation of self-supporting film using soluble aniphosphorylated polymer) Dedoped aniphosphorylated polymer obtained in Example 1 (intrinsic viscosity [η measured in N-methyl-2-pyrrolidone at 30 ° C] 1.23 dl / g) 5 g of powder was added little by little to 95 g of N-methyl-2-pyrrolidone and dissolved at room temperature to obtain a black-blue solution. When this solution was vacuum-filtered with a G3 glass filter, the amount of insolubles remaining on the filter was extremely small. The filter was washed with acetone, and the remaining insolubles were dried and weighed.
mg. Thus, the polymer is 98.5% dissolved,
Insolubles were 1.5%.

The polymer solution thus obtained was cast on a glass plate, wrung with a glass rod, and then N-methyl-2-pyrrolidone was evaporated in a hot air circulating drier. Thereafter, the polymer film was naturally peeled off from the glass plate by immersing the glass plate in cold water, thus obtaining a polymer film having a thickness of 40 μm.

After washing this film with acetone, it was air-dried at room temperature to obtain a film having a copper-colored metallic luster.

Films differ in strength and solubility depending on the drying temperature. When the drying temperature is 100 ° C. or lower, the obtained film dissolves in a small amount in N-methyl-2-pyrrolidone and has relatively low strength. However, the film obtained by heating at a temperature of 130 ° C. or more is very tough and does not dissolve in N-methyl-2-pyrrolidone or other organic solvents. Also, it does not dissolve in concentrated sulfuric acid. Thus, when heated at a high temperature, the polymer molecules are expected to crosslink with each other in the process and become insoluble.

The undoped film thus obtained is
The conductivity was in the order of 10 ^-11 S / cm.

The film did not break even after being bent 10,000 times, and the tensile strength was 850 kg / cm ² .

Example 3 (Doping of self-supporting film with protonic acid) In Example 2, the self-supporting film obtained by heating and drying at 160 ° C. for 2 hours was placed in a 1N aqueous solution of sulfuric acid, perchloric acid and hydrochloric acid at room temperature for 66 hours. After soaking for a time, the film was washed with acetone and air-dried to obtain a conductive film.

Each of the films exhibited a dark blue color, and the electrical conductivity was 9 S / cm, 13 S / cm, and 6 S / cm, respectively. The tensile strength of the film doped with perchloric acid was 520 kg / cm ² .

Example 4 (Both spectra and structure of a polymer soluble in an undoped state and a polymer in an insoluble film) The soluble polymer obtained in Example 1 (measured in N-methyl-2-pyrrolidone at 30 ° C.) Intrinsic viscosity [η] 1.23dl / g)
FIGS. 6 and 7 show FT-IR spectra of the powder and the insoluble polymer film obtained in Example 2 by the KBr tablet method, respectively.
Shown in the figure. In Example 2, the spectrum of the insoluble polymer film shows a slight absorption at 1660 cm ^-1 which is considered to be due to the residual solvent N-methyl-2-pyrrolidone, but the two spectra are almost the same. It is recognized that although the solvent is insoluble by cross-linking by heating and drying the solvent after casting of the polymer, no significant change has occurred in the chemical structure.

FIG. 8 shows the results of thermogravimetric analysis of the soluble polymer powder and the insoluble polymer film. All have high heat resistance. Considering that the insoluble film does not decompose to a higher temperature and is insoluble in concentrated sulfuric acid, it indicates that the polymer molecules are crosslinked in the insoluble film.

FIG. 9 shows an ESR spectrum. The spin concentration of the soluble polymer is 1.2 × 10 ¹⁸ spin / g, and as the heating temperature increases, the spin concentration increases, indicating that radicals are generated by heating. It is believed that this radical coupling causes the polymer to crosslink and render the heated film insoluble.

Next, the results of elemental analysis of the soluble polymer and the insoluble polymer are shown below.

Soluble polymer C, 77.19; H, 4.76; N, 14.86 (total 96.81) Insoluble polymer C, 78.34; H, 4.99; N, 15.16 (total 94.49) Based on this elemental analysis, standardized to C12.00 The composition formula of the soluble polymer is C _12.00 H _8.82 N _1.98 , and the composition formula of the insoluble polymer is C _12.00 H _9.11 N _1.99 . On the other hand, similarly, the quinone diimine structural unit and the phenyldiamine structural unit normalized to C12.00 are as follows, respectively.

Quinone diimine structural unit C ₁₂ H ₈ N ₂ Phenylenediamine structural unit C ₁₂ H ₁₀ N _{2 Accordingly} , as described above, both the soluble polymer and the solvent-insoluble polymer mainly contain the quinone diimine structural unit and the phenylenediamine structural unit as a main repeating unit. It is a polymer having a unit.

Next, the reflection spectra in the visible to near infrared region of the undoped film obtained in Example 2 and the film doped with perchloric acid obtained in Example 3 are shown in FIG. 10, respectively. In the undoped state, almost near-infrared light is reflected, but after doping, near-infrared light is absorbed, and it is recognized that there is almost no reflection. This is based on absorption by polarons or bipolarons which provides the conductivity created by the prontoic acid doping.

By doping the undoped film with perchloric acid, the ESR absorption is greatly increased, and the spin concentration reaches 3.8 × 10 ²¹ spin / g. This is derived from the generated polaron, a semiquinone radical.

Example 5 8 g of an organic solvent-soluble polyaniline (intrinsic viscosity [η] 1.23 dl / g) undoped in the same manner as in Example 1 was added little by little to 100 g of N-methyl-2-pyrrolidone and dissolved to give a black solution. I got

This solution was applied to a polyethylene terephthalate film as a shielding base material and dried at 120 ° C. for 5 minutes to obtain a 13 μm thick organic solvent-soluble polyaniline self-supporting film. This film was doped with polystyrene sulfonic acid to obtain a conductive polyaniline film having a conductivity of 9 S / cm.

With respect to this conductive polyaniline film, the electromagnetic wave shielding characteristics were evaluated using a spectrum analyzer (TR4172 manufactured by Advanced Test Co., Ltd.) (10 MHz to 1 GHz).
z).

As shown in FIGS. 11 and 12, the results up to 40 MHz
It is recognized that it has a shielding effect of 0 dB or less and 200 dB or less up to 200 MHz.

Example 6 An organic solvent-soluble polyaniline film before doping obtained in Example 5 was doped with polystyrene sulfonic acid in the same manner, and five conductive polyaniline films obtained in this manner were stacked, and the same as in Example 1 was performed. Then, the shielding effect was measured.

As shown in FIG. 11 and FIG.
It is recognized that it has a shielding effect of 0 dB or less and 24 dB or less up to 200 MHz.

Example 7 A carbon nonwoven fabric was placed on a plate heated to 100 ° C., and the polyaniline solution prepared in Example 5 was applied and impregnated thereon to prepare a composite shielding agent. This composite shielding material had a thickness of 600 μm and an electric conductivity of 5 S / cm.

As shown in FIG. 11 and FIG. 12, the results up to 200 MHz
It is recognized that it has a shielding effect of 40 dB or more and 20 dB or more up to 1 GHz.

[Brief description of the drawings]

FIG. 1 is a laser Raman spectrum when the organic solvent-soluble polyaniline in the undoped state according to the present invention is excited by light having a wavelength of 457.9 nm, and FIG. FIG. 3 shows a laser Raman spectrum when excited by light having a different wavelength, and FIG. 3 shows a laser Raman spectrum obtained when the same organic solvent-soluble polyaniline as shown in FIG.
FIG. 4 is an electronic spectrum of an N-methyl-2-pyrrolidone solution of polyaniline in the undoped state and soluble in an organic solvent according to the present invention. FIG. 5 shows the results of the organic solvent-soluble polyaniline according to the present invention.
FIG. 6 is a graph showing the molecular weight distribution by GPC, and FIG.
FT-IR spectrum by the KBr tablet method, FIG. 7 is an FT-IR spectrum of the solvent-insoluble film obtained by casting the above-mentioned organic solvent-soluble polyaniline by the KBr tablet method, and FIG. FIG. 9 is a diagram showing a change in ESR spectrum when the organic solvent-soluble polyaniline is heated, and FIG. 10 is a diagram showing the undoped organic solvent-soluble polyaniline and the perchloric acid. 3 is a reflection spectrum in the near infrared region of a film doped with. 11 and 12 are graphs showing the effect of the electromagnetic wave shielding material according to the present invention.

Claims (2)

(57) [Claims] (1) General formula (In the formula, m and n each represent a mole fraction of a quinone diimine structural unit and a phenylenediamine structural unit in the repeating unit, and are 0 <m <1, 0 <n <1, and m + n = 1). A polymer having as a repeating unit, an organic polymer that is soluble in an organic solvent in a undoped state is dissolved in the organic solvent, the obtained polymer composition is applied on a shield substrate, and dried, A thin film of polyaniline soluble in organic solvent was formed, and then the thin film was pKa value of 4.8.
A method for producing an electromagnetic wave shielding material, characterized by doping with the following protonic acid. 2. The general formula In the formula, m and n indicate the mole fractions of the quinone diimine structural unit and the phenylenediamine structural unit in the repeating unit, respectively, where 0 <m <1, 0 <n <1, and m + n = 1. ) As a main repeating unit, which is soluble in an organic solvent in an undoped state and 457.
Among the skeleton vibrations of para-substituted benzene in the laser Raman spectrum obtained by exciting with light of 9 nm wavelength,
Than 1600 cm ^-1 is the ratio Ia / Ib of the Raman line intensity Ib skeletal stretching vibration appearing at lower wavenumber than the intensity Ia and 1600 cm ^-1 of the Raman line skeletal stretching vibration appearing in the number of high wave is 1.0 or more organic polymers Dissolved in an organic solvent, the obtained polymer composition is applied on a shield substrate, and dried to form a thin film of an organic solvent-soluble polyaniline.
A method for producing an electromagnetic wave shielding material, comprising doping with a protonic acid having a pKa value of 4.8 or less.