JPH06340754A - Method for providing polymer molding with electrical conductivity - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a method for imparting stable conductivity without impairing the transparency, color or mechanical properties inherent in polymer materials. [Structure] An insulating polymer molding (base material) is attached or impregnated with a polycyclic aromatic amine compound, and then contacted with a solution containing an oxidizing agent to form a polycyclic aromatic amine compound-containing group. A method for imparting conductivity to a polymer molded article, which comprises oxidatively polymerizing the material inside or on the surface thereof.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for imparting conductivity to a polymer molding. In particular, the present invention provides a conductive polymer molded body that has long-lasting conductivity and is not affected by environmental changes such as temperature and humidity. In particular, it is used as an antistatic material in electronic and electric products and the construction field. Useful for.

[0002]

2. Description of the Related Art In recent years, with the rapid development of electric and electronic equipment, static sensitive parts have come to be used in various fields, and static control technology has become more important. Almost all general-purpose polymers and engineering plastics used for electric / electronic devices and indoor desks and floors in which they are placed are inherently insulating materials, so these polymer materials occur. The problem that static electricity impairs the normal operation of electronic components has been highlighted. In particular, the potential generated in the polymer material in the dry state is large, and the antistatic property (that is, conductivity) that is not affected by the environment
Materials are desired. Further, a display device such as a cathode ray tube requires a transparent antistatic material.

Conventionally, in order to make a resin conductive, a method of adding carbon black or carbon fibers to the resin (for example, Japanese Patent Publication No. 3-50792), metal powders such as iron, copper, nickel and stainless steel, A method of adding fibers to a resin, and a method of kneading various cationic, anionic and nonionic surfactants into the resin (for example, JP-A-58-12).
5741, JP-A-64-24845, JP-A-1-135857) and the like are known.

However, it is difficult to obtain a transparent resin and the hue is limited by the method of adding carbon or metal to the resin. It also causes the mechanical properties of the resin to deteriorate. On the other hand, in the method using a surfactant, the antistatic effect is easily affected by the external environment such as humidity and temperature, and its durability is poor.

On the other hand, as a method for producing a conductive organic polymer, an electrolytic oxidative polymerization method using a typical monomer such as pyrrole, aniline and thiophene and a chemical oxidative polymerization method are known. The electrolytic oxidative polymerization method is a method in which an indicator electrolyte and a monomer to be polymerized are dissolved in a suitable solvent, and a constant voltage is applied between electrodes inserted in this solution to form a conductive organic polymer on the anode. . According to this method, 10S /
Although it is possible to obtain a high conductivity of cm or more, it is difficult to mass-produce large-scale products and large-scale products, and the manufacturing cost is high. Moreover, the scope of this method is narrow, since the substrate must already be electrically conductive.

The chemical oxidation method is a method of oxidizing and polymerizing a monomer by using an oxidizing agent. One method is to dissolve the monomer in a suitable solvent and polymerize it with a suitable oxidizing agent. Compared with the electrolytic oxidative polymerization method, this method can obtain a polymer at a low cost and is rich in mass productivity, but generally has low conductivity, the polymer is obtained as a powder, and the polymer is generally insoluble and infusible. It has the drawback of being extremely inferior in moldability.

In order to improve such a defect of the conductive polymer, a method of impregnating a polymer molding with a monomer and then polymerizing the monomer with an oxidizing agent to prepare a conductive composite molding is disclosed. (JP-A-62-167329 and JP-A-62-167330). However, there is no established method for forming a conductive polymer film having good transparency on the surface of a molded body.

As a method for producing a polycyclic aromatic amine compound, only an example of electrochemical oxidative polymerization of naphthylamine has been reported (Reference example: Electroc).
him. Acta, 32, 1223 (1987), J. Am.
Chem. Soc. Jpn. , 11, 2038 (198
7), J. Electroanal. Chem. , 12
5, 459 (1981)), there is no report of chemical oxidative polymerization.

[0009]

DISCLOSURE OF THE INVENTION The present invention solves the problems of the conventional method of imparting conductivity to an insulating polymer material, and impairs the original transparency, color or mechanical properties of the polymer material. A method for imparting stable conductivity is provided.

[0010]

Means for Solving the Problems The inventors of the present invention used a polycyclic aromatic amine compound (monomer) and dissolved it in a solvent to obtain a solution, which was an insulating polymer molded article as a base material. The base material is impregnated with the monomer by contacting with, and thereafter, the transparency or color of the base material is increased by contacting the base material with a solution containing an oxidant to oxidatively polymerize the monomer.
The inventors have found that stable conductivity is imparted without impairing mechanical properties, and have reached the present invention.

That is, the present invention provides a method for imparting conductivity to an insulating polymer molded body (base material), in which a polycyclic aromatic amine compound is attached to the insulating polymer molded body (base material). After impregnation, contact with a solution containing an oxidant,
The present invention relates to a method for imparting conductivity to a polymer molding, which comprises subjecting a polycyclic amine compound to oxidative polymerization inside or on the surface of a substrate.

Examples of the polycyclic aromatic amine compound used in the present invention include aminonaphthalenes such as 1-aminonaphthalene, aminoanthracenes such as 1-aminoanthracene, aminoquinolines such as 5-aminoquinoline, and the like. Examples thereof include aminoisoquinolines such as 5-aminoisoquinoline, aminoacridines, and aminoquinaridines. Also, these compounds in which an alkyl group or an alkoxy group having 1 to 20 carbon atoms is introduced into an aromatic ring can be used. The polymers obtained by the oxidative polymerization of these compounds form a conductive film having excellent transparency because they absorb less light in the visible region than polypyrrole and polyaniline.

In the present invention, as a method for adhering or impregnating a polycyclic aromatic amine compound on a substrate and then contacting it with a solution containing an oxidizing agent, the following methods are specifically mentioned. That is, first, the insulating polymer molded body which is the base material is added to the above polycyclic aromatic amine compound (monomer) in an amount of 1: 1.
Contact with a solution containing more than one species (diffusion step), and then
It includes a step of incompletely drying the base material to which the monomer and the solvent are attached or impregnated (drying step), and bringing the base material into contact with a solution containing an oxidizing agent to polymerize the monomer (oxidative polymerization step).

In the solution containing the monomer of the diffusion step of the present invention, the solvent used is a solvent (non-solvent) that does not dissolve the polymer constituting the substrate, a mixture of two or more non-solvents, and the substrate. Is a mixture of a solvent (good solvent) for dissolving the polymer to be used and one or more kinds of non-solvents, and it is necessary that all of them are volatile. Here, the non-solvent is a solvent that does not dissolve or swells the polymer that constitutes the substrate, but does not dissolve, and the good solvent is a solvent that dissolves the polymer that constitutes the substrate and gives a uniform solution. Is.
The specific types of these differ depending on the polymer (references, "Polymer Handbook", Third Edition, JOHN WI).
LEY & SONS, 1989). For example, when the base material is polyvinyl chloride, the good solvent is cyclohexanone, nitrobenzene, butyl acetate, dichloroethane, tetrahydrofuran, methyl isobutyl ketone, methyl ethyl ketone, dimethylformamide, etc., and the non-solvent is methanol, ethanol, n-butanol. , Ethylene glycol, n-hexane, benzene, acetone and the like.

When the solvent used in the diffusion step is a mixture of a non-solvent and a good solvent, the good solvent content is preferably less than 5% by volume. More preferably, it is less than 2% by volume. However, the non-solvent and the good solvent mentioned here do not have to be single solvents, and may be a mixture of a plurality of solvents. If the composition of the solvent does not satisfy these conditions, there is a high risk that the conductivity of the finally obtained polymer molded article will be low, the surface will be uneven, and the transparency will deteriorate due to coloring etc. .

Further, in the present invention, the solvent used for the monomer solution preferably contains a non-solvent having an affinity for the base polymer in an amount of 5 to 50% by volume. The non-solvent having an affinity for the base polymer here means that the solubility parameter is -5 (M
Pa) ^1/2 to +5 (MPa) ^1/2 , which is a non-solvent, more preferably -3 (MPa) ^1/2 to +.
It is a non-solvent in the range of 3 (MPa) ^1/2 .

In the diffusion step, the concentration of the monomer in the solution containing the monomer is preferably 0.5 to 20% by weight, more preferably 1 to 10% by weight. The time for bringing the polymer molding of the base material into contact with this monomer solution is preferably 20 seconds to 30 minutes, more preferably 1 minute to 10 minutes. This contact time is 20
If it is shorter than a second, the impregnation of the base material with the monomer becomes insufficient, and finally a polymer molded body having high conductivity cannot be obtained.
If the contact time is longer than 30 minutes, not only the base material may be deformed, the transparency of the finally obtained polymer molded article may be deteriorated, but also the manufacturing cost is increased.

In the present invention, after the monomer solution is brought into contact with the base material, it is necessary to leave it in the air as it is under normal pressure without being washed with a solvent or the like, and dry it for a proper time (that is, naturally dry it). There is. At this time, in the first stage of drying, it is desirable to quickly remove the excess monomer solution adhering to the surface of the substrate by blowing gas, using a roll, a brush, a sweeper or the like.

When the oxidative polymerization is carried out without drying the substrate, it is difficult to finally obtain a polymer molded article having high conductivity, and also when the drying time is too long, the conductivity is finally determined. It is not possible to obtain a polymer molded product with high efficiency. Drying
It may be in air, but may be carried out in a gas atmosphere containing at least one gas selected from oxygen, nitrogen, argon, helium, and carbon dioxide as a main component. The drying time is preferably controlled to an optimum time between 5 seconds and 5 minutes, more preferably 10 seconds to 3 minutes. The drying temperature is lower than the boiling points of the monomer and the solvent used, and preferably 6
It is 0 ° C or lower.

The oxidizing agents used in the present invention include iron (III) salts, molybdenum (V) salts and ruthenium (II) salts.
I) salts, chromic acid (IV) salts, dichromic acid (VI) salts, permanganic acid (VII) salts, and other metal-based oxidizing agents, ammonium persulfate and other persulfates, hydrogen peroxide, benzoyl peroxide, and the like. There are peroxides, peroxo acids such as peroxodisulfate and potassium peroxodisulfate, and chloric acids such as hypochlorous acid and potassium hypochlorite.

Further, a highly conductive polymer molding can be obtained by allowing a doping agent to coexist in the oxidation reaction medium. Such doping agents include Lewis acids, protic acids and salts thereof. Examples of the protic acid include inorganic acids such as hydrochloric acid and sulfuric acid, methanesulfonic acid, ethanesulfonic acid, benzenesulfonic acid, toluenesulfonic acid and dodecylbenzenesulfonic acid. As the Lewis acid, arsenic pentafluoride, antimony pentafluoride,
There are boron trifluoride, boron trichloride, ferric chloride, stannic chloride, titanium tetrachloride, zinc chloride, cupric chloride and the like.

The polymer molded article in the present invention may be either thermosetting or thermoplastic and is not particularly limited. Examples of thermoplastic resins include polyolefins (polyethylene, polypropylene, ethylene vinyl acetate copolymer, etc.), polyvinyl chloride, polystyrene, ABS resin, polyamide (nylon 6, nylon 66, nylon 12, etc.), polyimide, polyethylene. Terephthalate (PE
T), polybutylene terephthalate (PBT), polyesters including polyesters showing optical anisotropy, polycarbonate, polyether ether ketone, polyether ketone, polyoxymethylene, polyethylene oxide, polypropylene oxide, polyphenylene oxide, polyphenylene sulfide, There are polysulfone and polyether sulfone. Examples of thermosetting resins include phenolic resins, unsaturated polyesters, epoxy resins and the like.

These polymer moldings include stabilizers, plasticizers, flame retardants, additives such as lubricants, reinforcing materials such as glass fibers and whiskers, inorganic fillers such as calcium carbonate, clay, silica, mica and talc. May be added.

The solvent used for the solution containing the oxidizing agent in the oxidative polymerization step of the present invention must be such that the oxidizing agent is not isolated and precipitated and is not subjected to the oxidation reaction by the oxidizing agent. Examples of such solvents include water, methanol, ethanol, propanol, isopropanol, butanol, pentanol, hexanol, octanol and other aliphatic alcohols, hexafluoroisopropanol and other halogenated alcohols, phenol, chlorophenol, cresol, fluoro. Phenols such as phenol and polar solvents such as dimethylacetamide are preferable. Furthermore, hydrocarbons such as benzene, toluene, xylene, hexane, and cyclohexane, halogenated compounds such as chloroform, and nonpolar solvents such as various ethers can be mentioned as candidates. In this case, since the oxidation potential varies depending on the type of solvent, a solvent that gives a high oxidation potential and a solvent that gives a low oxidation potential are mixed appropriately to obtain an oxidation potential suitable for obtaining a highly conductive polymer. It is possible to adjust. Further, the solvent used here needs to be one that does not dissolve or greatly swell the polymer molding of the base material.

According to the studies made by the present inventors, the conductivity of the conductive polymer formed on the surface of the polymer molded body largely depends on the oxidation potential during the oxidative polymerization. That is, if the oxidation potential is too large or too small, the conductivity becomes low. The oxidation potential during the polymerization reaction can be controlled by the type of solvent, the oxidant / reductant ratio of the oxidant, and the temperature. Oxidizer (eg FeC
The addition amount of the reduced product (FeCl ₂ ) of 1 ₃ ) is 50 mol% or less, preferably 0.01 to 20 mol% with respect to the oxidant. Is obtained.

After the oxidative polymerization step, it is desirable to thoroughly wash the polymer molding to remove the remaining oxidizing agent and its reduced product. As the solvent, those similar to those used in the oxidative polymerization step can be used. Furthermore, after washing, it is desirable that the polymer molded article be thoroughly dried to remove the residual solvent. If an oxidant or its reduced product or solvent remains in the resulting conductive polymer molded product, it may cause deterioration of the conductive coating film on the surface due to heat during secondary molding of this, or gas during use. It is inconvenient because it causes

In the present invention, in order to impart conductivity without impairing the hue and transparency of the substrate, the thickness of the conductive film formed on the surface is preferably 0.02 μm to 20 μm, more preferably It is 0.05 μm to 5 μm.
If the thickness of the coating is less than 0.02 μm, sufficient conductivity cannot be obtained, and if it is greater than 20 μm, the transparency becomes poor, and the coating may be cut or peeled during molding, and the conductivity is likely to be impaired. Problem arises.

Further, in the present invention, the conductive polymer produced by the above-mentioned oxidative polymerization is chemically or electrochemically reduced, and then oxidized by chemical oxidation or electrolytic oxidation and doping is performed to obtain an antistatic effect. It can be further enhanced. Examples of the reducing agent used for the chemical reduction include hydrazine, hydrazine hydrate, hydrazine such as phenylhydrazine, lithium aluminum hydride,
Examples thereof include metal hydrides such as sodium borohydride. The chemical reducing agent is usually used in a molar amount of 1 to 10 times per nitrogen atom of the polymer, but is not necessarily limited thereto. In the electrolytic reduction, the surface of the molded body is used as a cathode to carry out dedoping by passing a current at an applied voltage of 0.01 to several tens of volts. After the reduction, the neutral conductive polymer film is chemically re-oxidized with an oxidant and doped. As the oxidant used for such reoxidation, any compound having an oxidizing power sufficient to reoxidize the reduced neutral polymer and having an electron accepting property effective as a dopant can be used. . Such oxidizing agents include halogens such as iodine, bromine and chlorine, arsenic pentafluoride, antimony pentafluoride, boron trifluoride, boron trichloride, ferric chloride, stannic chloride, titanium tetrachloride, Lewis acids such as zinc chloride and cupric chloride, hydrochloric acid, sulfuric acid and salts thereof (for example, potassium hydrogen sulfate, sodium sulfate, sodium perchlorate, potassium perchlorate, iron perchlorate, etc.), or borofluoric acid. And salts thereof (for example, sodium borofluoride, potassium borofluoride, ammonium borofluoride, tetraalkylammonium borohydride, etc.) and the like.

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

[0030]

EXAMPLES In the following examples, the surface resistivity of the film was measured using a surface resistance measuring device Loresta AP (manufactured by Mitsubishi Yuka).

Example 1 In a mixed solution (diffusion solution) of 90 ml of hexane, 10 ml of acetone and 3 g of 1-aminonaphthalene, 50 mm ×
A 1-aminonaphthalene was impregnated into the film (both sides) by immersing a hard vinyl chloride film having a size of 50 mm and a thickness of 0.3 mm for 3 minutes at room temperature. After leaving this film in dry air at room temperature for 30 seconds, a solution of acetonitrile / methanol (volume ratio 85:15) containing 1 M ferric chloride and 1 M p-toluenesulfonic acid (oxidizing solution). 1-aminonaphthalene impregnated in the vicinity of the surface of the film was polymerized by immersing in 1) for 3 minutes at room temperature. Subsequently, the film was washed with methanol to remove residual iron chloride, and dried under reduced pressure for about 10 hours.

Here, hexane, acetone, methanol and acetonitrile are non-solvents for polyvinyl chloride. The polyvinyl chloride film used was obtained by blending 100 parts of vinyl chloride resin (degree of polymerization about 800), 3 parts of diethyl tin malate, 10 parts of MBS resin and 3 parts of epoxidized soybean oil.

When the cross section of the obtained film was observed by a transmission electron microscope, it was confirmed that a continuous phase stained with osmium tetroxide was present at a depth of about 0.1 μm from the surface. Has a surface resistivity of about 1 MΩ /
□, and had sufficiently large conductivity as an antistatic material. In addition, the light transmittance is in the visible region (wavelength 500n
m) was about 70%, and the transparency was good. Further, in the cross-cut test and the peeling test using cellophane tape defined in JIS K5400, peeling of the conductive layer on the film surface was not observed at all.

Example 2 A polyvinyl chloride film was treated in the same manner as in Example 1 except that 1-aminonaphthalene in Example 1 was changed to 1-aminoanthracene.

The surface resistivity of the obtained film is about 1.5.
It was MΩ / □, which was sufficient for preventing static electricity. The light transmittance of the film is in the visible range (wavelength 500 nm)
Was about 75%. Further, in the cross-cut test and the peeling test using cellophane tape defined in JIS K5400, peeling of the conductive layer on the film surface was not observed at all.

Example 3 A polyvinyl chloride film was treated in the same manner as in Example 1 except that 5-aminoisoquinoline was used instead of 1-aminonaphthalene in Example 1.

The surface resistivity of the obtained film is about 10M.
Ω / □, and the light transmittance of the film was about 85% in the visible region (wavelength 500 nm). Furthermore, JIS K
In the cross-cut test defined by 5400 and the peeling test with cellophane tape, peeling of the conductive layer on the film surface was not observed at all.

Comparative Example 1 A polyvinyl chloride film was treated in the same manner as in Example 1 except that 1-aminonaphthalene in Example 1 was changed to aniline. The surface resistivity of the obtained film is about 500.
KΩ / □ was better than that of Example 1, but the film exhibited a greenish black color and the light transmittance at a wavelength of 500 nm was about 50%.

Comparative Example 2 94 ml of acetonitrile was used as the diffusion solution in Example 1.
A polyvinyl chloride film was treated in the same manner as in Example 1 except that 6 ml of nitrobenzene (a good solvent for polyvinyl chloride) and 3 g of 1-aminonaphthalene were dissolved. The surface resistivity of the obtained film is about 10 MΩ / □
The surface was non-uniform, and the light transmittance of the film was poor at about 30% in the visible region. In this film treatment, when the drying step was not performed, the surface resistivity of the film was about the same as when the drying step was performed, but the surface was more uneven and the transparency was significantly reduced.

[0040]

According to the invention, conductivity can be easily imparted to a polymer molded body. At this time, the transparency and hue of the base material are not significantly impaired, the obtained conductivity lasts for a long time, and is hardly affected by the temperature and humidity. Therefore, when the method of the present invention is used in the field of electronic / electrical parts, materials such as cases and IC trays, or construction materials, it is extremely useful for preventing damage due to static electricity of semiconductors and explosion accidents due to discharge.

Front page continuation (72) Inventor Masazumi Hasegawa 1-17-11-3, Shinnanyo-shi, Yamaguchi Prefecture (72) Inventor Yoshiyuki Miyaki 3-4-10, Yokkaichi, Mie

Claims (4)

[Claims] 1. A polycyclic aromatic amine compound is prepared by adhering or impregnating an insulating polymer molding (base material) with a polycyclic aromatic amine compound, and then contacting it with a solution containing an oxidizing agent. A method for imparting electrical conductivity to a polymer molded article, comprising: oxidatively polymerizing the polymer inside or on the surface of the substrate. 2. A polymer molding according to claim 1, wherein the polycyclic aromatic amine compound is aminonaphthalene, aminoanthracene, aminoquinoline or aminoisoquinoline. Method. 3. A step of bringing a base material into contact with a solution containing a polycyclic aromatic amine compound (diffusion step), and a step of drying the base material to which the polycyclic aromatic amine compound and the solvent are attached or impregnated (drying Conducting the polymer molded body according to claim 1 or 2, which comprises a step of contacting a substrate with a solution containing an oxidizing agent to polymerize a polycyclic aromatic amine compound (oxidative polymerization step). Method of imparting sex. 4. The polymer molding according to claim 1, wherein the solution containing an oxidizing agent contains an inorganic or organic protonic acid or a salt thereof as a doping agent. A method of imparting conductivity to a body.