JPH05186617A - Conductive composite form and its production - Google Patents

Abstract

PURPOSE:To provide the composite form having excellent conductivity for a long period by bringing a synthetic resin substrate coated with a vinyl chloride copolymer containing an oxidizing agent into contact with the vapor of a heterocyclic compound to form a conductive compound coating film on the surface of the synthetic resin substrate. CONSTITUTION:(A) A2: the coating film of a vinyl chloride copolymer (having a vinyl chloride chain content of 5-95% and containing a vinyl ester, an acrylic acid derivative, etc., as other monomers) containing 5-50wt.% of an oxidizing agent [e.g. iron (III) salt, molybdenum (v) salt] is formed on A1: a synthetic resin substrate, and (B) the coated synthetic resin substrate is brought into contact with the vapor of one kind or more of heterocyclic compounds (pyrrole compounds, furan compounds or thiophene compounds) and aniline compounds at 0-200 deg.C for 3sec to 5min to form a conductive compound coating film comprising the vinyl chloride copolymer and the polymers of the heterocyclic compound and/or the aniline compound on the surface of the synthetic resin substrate to impart durable conductivity.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conductive composite by imparting conductivity to the surface of a base material and a method for producing the same. In particular, the present invention provides a material for antistatic and electromagnetic shielding that has long-lasting conductivity and is not affected by environmental changes such as temperature and humidity, and is useful in the fields of electronic and electrical products and construction. is there.

[0002]

2. Description of the Related Art In recent years, with the rapid development of electric and electronic devices, parts sensitive to static electricity and electromagnetic waves have been used in various fields, and the importance of static electricity management technology and electromagnetic wave shielding technology has increased. .. Almost all general-purpose polymers and engineering plastics used for electric / electronic devices and indoor desks and floors in which they are placed are essentially insulating materials, so static electricity generated in these polymeric materials The problem that electromagnetic waves from the outside impair the normal operation of electronic components has been highlighted. In particular, there is a demand for a conductive material that has a large electric potential generated in a polymer material in a dry state and is not affected by the environment. 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 fiber to the resin (for example, Japanese Patent Publication No. 3-50792), metal powders such as iron, copper, nickel and stainless steel, and 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, in the method of adding carbon or metal to the resin, it is difficult to obtain a transparent resin, and the hue is also limited. It also causes the mechanical properties of the resin to deteriorate. On the other hand, in the method using a surfactant, the conductivity 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 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, it is possible to obtain high conductivity of 10 S / cm or more, but it is difficult to mass-produce 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 of the methods is to dissolve the monomer in a suitable solvent and polymerize it with a suitable oxidizing agent. Compared with the electrolytic oxidation polymerization method, this method provides 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. As another method, there is a method of forming a conductive thin film by polymerizing a monomer deposited on a substrate with an oxidizing agent. However, in this case, the conventional technique also has drawbacks such that the conductivity of the produced polymer is not high and the produced coating film is easily peeled off from the substrate.

[0007]

DISCLOSURE OF THE INVENTION The present invention solves the problems in the method of imparting electrical conductivity to a substrate, and has stable electrical conductivity without impairing the transparency, color or mechanical properties of the substrate. Provide the material.

[0008]

Means for Solving the Problems That is, the present inventors have made earnest studies and found that aromatic compounds, particularly nitrogen, oxygen,
By using a heterocyclic compound containing a heteroatom such as sulfur and bringing this vapor into contact with a synthetic resin substrate coated with a vinyl chloride-based copolymer containing an oxidant, the transparency or color of the substrate and the mechanical The present inventors have found that stable conductivity is imparted to a base material without impairing the physical properties of the base material and have reached the present invention.

That is, according to the present invention, on the surface of a synthetic resin substrate, one or more compounds selected from a vinyl chloride copolymer having a vinyl chloride chain content of 5 to 95% by weight and a heterocyclic compound are provided. The present invention relates to a conductive composite body formed by forming a conductive composite coating film made of a united body and a method for producing the same.

The vinyl chloride-based copolymer in the present invention has an average of 5 to 5 vinyl chloride bond units in the molecule.
It contains 95% by weight. Specific examples of the monomer other than vinyl chloride constituting the copolymer include vinyl acetates such as vinyl acetate, vinyl butyrate and vinyl propionic acid and saponified products thereof, vinyl ethers such as vinyl ethyl ether, maleic acid and itacone. Unsaturated dicarboxylic acid such as acid, maleic anhydride, unsaturated dicarboxylic acid anhydride such as itaconic anhydride, methylmaleimide,
Unsaturated dicarboxylic acid imides such as hexylmaleimide, acrylic acid, acrylic acid derivatives such as methyl acrylate, methacrylic acid derivatives such as methacrylic acid and methyl methacrylate, 2- or 4-vinylpyridine, N-vinyl-2-pyrrolidone Such as vinyl heterocyclic compounds. The vinyl chloride copolymer used in the present invention is composed of vinyl chloride and at least one kind of monomer selected from the above. Monomers other than vinyl chloride may be contained in the copolymer in an amount of 0.5 to 95% by weight. Such a binder polymer has an affinity for a monomer that becomes a polymer composed of a conjugated chain when oxidatively polymerized, and has good adhesion to a wide range of base materials.
In particular, the effect is great when the substrate is a polyvinyl chloride type.

Examples of the heterocyclic compound used in the present invention include a 5-membered heterocyclic compound such as a pyrrole derivative, a furan derivative, and a thiophene derivative, and a 6-membered aromatic compound such as aniline and benzidine. ..
The pyrrole derivative is an unsubstituted pyrrole, an N-substituted pyrrole such as an N-alkylpyrrole, or a 3-alkylpyrrole having a C _{1 to} C ₆ alkyl group, an alkoxy group or a halogen atom at the 3-position or the 3- and 4-positions. , 3,4-dialkylpyrrole, 3-alkoxypyrrole, 3,4-dialkoxypyrrole, 3-chloropyrrole, or 3,4-dichloropyrrole. The furan derivative may be an unsubstituted furan, a 3-position or a 3-position.
3-alkylfuran having a C ₁ -C ₆ alkyl group, an alkoxy group or a halogen atom at the 4- and 4-positions, 3,4
-Dialkyl furan, 3-alkoxy furan, 3,4-
Examples include dialkoxyfuran, 3-chlorofuran, and 3,4-dichlorofuran. The thiophene derivative may be an unsubstituted thiophene or C _{1 at the} 3-position or at the 3- and 4-positions.
Alkyl group -C _6, 3-alkylthiophene having an alkoxy group or a halogen atom, 3,4-dialkyl thiophene, 3-dialkoxythiophene, 3,4dialkoxythiophene, 3-chloro-thiophene or 3,
4-dichlorothiophene and the like.

The oxidizing agents used in the present invention include metal-based and non-metal-based oxidizing agents, but the oxidizing agents having the same oxidation potential as the electrolytic oxidative polymerization method for producing a highly conductive polymer in the reaction medium. Agents are preferred. Examples of the metal-based oxidizing agent for pyrroles, furans, and thiophenes include iron (III) salts, molybdenum (V) salts, ruthenium (III) salts, and the like. Examples of aniline metal-based oxidizing agents include chromic acid (IV) salts, dichromic acid (VI) salts, permanganic acid (VII) salts, and the like. On the other hand, as the non-metallic oxidant, hydrogen peroxide,
There are peroxides such as benzoyl peroxide, peroxo acids such as peroxodisulfate and potassium peroxodisulfate, and oxygen acids such as hypochlorous acid and potassium hypochlorite. Depending on the application such as an IC tray or an IC carrier tape, it is necessary to wash the polymer molded body coated with a conductive film with pure water or the like to remove residual metals or to use a non-metallic oxidant.

The synthetic resin substrate in the present invention may be either a thermosetting resin or a thermoplastic resin and is not particularly limited. Examples of thermoplastic resins include polyolefins (polyethylene, polypropylene, ethylene vinyl acetate copolymer, etc.), polyvinyl chloride, polystyrene, A
BS resin, polyamide (nylon 6, nylon 66, nylon 12, etc.), polyimide, polyethylene terephthalate (PET), polybutylene terephthalate (PB)
T), polyesters including polyesters showing optical anisotropy, polycarbonate, polyether ether ketone, polyether ketone, polyoxymethylene, polyethylene oxide, polypropylene oxide, polyphenylene oxide, polyphenylene sulfide, polysulfone, polyether sulfone, etc. is there. Examples of thermosetting resins include phenolic resins, unsaturated polyesters, epoxy resins and the like.

These polymers include stabilizers, plasticizers, flame retardants, additives such as lubricants, glass fibers, reinforcing materials such as whiskers, calcium carbonate, clay, silica, mica,
An inorganic filler such as talc may be added.

The method for producing a conductive composite of the present invention is, for example, one or more kinds selected from heterocyclic compounds and aniline compounds on a synthetic resin substrate coated with a vinyl chloride copolymer containing an oxidizing agent. By bringing vapors of compounds (monomers) into contact with each other to form a complex of a polymer of these compounds and a vinyl chloride polymer.

In this case, the oxidant content of the vinyl chloride copolymer is 5 to 50% by weight, the temperature of the monomer vapor is 0 to 200 ° C., and the vapor and the vinyl chloride copolymer are in contact with each other. The time is preferably 3 seconds or more and 5 minutes or less. If this condition is not satisfied, it may be difficult to obtain the conductive composite that is the object of the present invention.

In the present invention, it is necessary to previously form a vinyl chloride-based copolymer coating containing an oxidizing agent on the surface of the synthetic resin substrate, but after mixing the vinyl chloride-based copolymer and the oxidizing agent. It may be applied to a base material, or a vinyl chloride copolymer may be applied to a synthetic resin base material and then impregnated with an oxidizing agent.

Specifically, for example, an oxidizing agent is added to a solution obtained by dissolving a vinyl chloride copolymer in a solvent and mixed,
This mixed solution may be applied to a substrate and the solvent may be evaporated.

The solvent used here is particularly preferably, if neither the vinyl chloride-based copolymer nor the oxidizing agent is isolated and precipitated when the vinyl chloride-based copolymer and the oxidizing agent are mixed. The solvent is not limited, and two or more kinds of solvents can be used in combination. Examples of such a solvent include aliphatic alcohols such as methanol, ethanol, propanol, isopropanol, butanol, pentanol, hexanol, and octanol, halogenated alcohols such as hexafluoroisopropanol, phenol, chlorophenol, cresol, and fluorophenol. The phenols, various ethers such as diethyl ether, ketones such as methyl isobutyl ketone and cyclohexanone, and polar solvents such as dimethylacetamide are preferable. Furthermore, hydrocarbons such as benzene, toluene, xylene, hexane, and cyclohexane, and nonpolar solvents such as halogenated compounds such as chloroform can be mentioned as candidates.

As another method for producing the conductive composite of the present invention, a solution obtained by dissolving an oxidizing agent, a vinyl chloride copolymer, and a monomer in a solvent is applied to a substrate and the solvent is evaporated. There is a method in which the monomer is polymerized while the above is performed to obtain a conductive composite.

In this case, the same solvent as that used when mixing the vinyl chloride copolymer and the oxidizing agent is used. In the solution applied to the base material, the concentration of the oxidant is preferably 1 to 30 with respect to 100 of the solvent in a weight ratio. Further, regarding the amounts of the monomer and the oxidant, it is desirable that the monomer concentration becomes 0.04 to 0.5 times (weight ratio) the oxidant concentration when both are mixed in the solution. The weight mixing ratio of the oxidizing agent and the vinyl chloride copolymer is 0.05 to 10: 1, preferably 0.1 to 2: 1.

Further, the composition of the above solution is such that the weight ratio of the oxidizing agent is 1 to 30 and the amount of the monomer is 0.
1 to 12, and the vinyl chloride copolymer is preferably 0.25 to 100. Further, it is desirable that the weight ratio of the monomer to the vinyl chloride copolymer is 0.1 to 0.5 and the weight ratio of the monomer to the oxidizing agent is 0.04 to 0.5. In addition, an oxidizer (eg FeCl 2
₃ ) the reduced form (FeCl ₂ ) of 50mo
You may add 1% or less, preferably 0.01 to 20 mol%.

In the present invention, when a solution obtained by dissolving an oxidizing agent, a vinyl chloride copolymer and a monomer is applied to a substrate, a general method is to use an oxidizing agent and a vinyl chloride copolymer. A solution (a) obtained by dissolving in the same solvent and a solution (b) obtained by dissolving a monomer in a solvent are prepared, and the solutions (a) and (b) are mixed, and immediately after mixing or a little time passes. After that, it is applied to the substrate. Alternatively, the oxidizing agent, the binder polymer, and the monomer may be dissolved in one solvent from the beginning. The time from the mixing of the oxidizer and the monomer to the coating is preferably within 5 hours. When the time is longer than that, the reaction proceeds too much in the solution to give a gelled product, which is not preferable. A brush, an applicator, spin coating, spraying, a dip coating method, or the like can be used as a method for applying the polymer molded body. The solvent is evaporated off from the solution-applied molded product at -10 to 50 ° C, preferably 0 to 40 ° C, in an air or nitrogen atmosphere.

On the other hand, when the concentration of the oxidant in the present invention is higher than the above range, the polymerization reaction rapidly progresses in the solution before coating on the substrate to form a granular material (gel), resulting in a uniform surface. A coating may not be obtained, and when the weight mixing ratio of the vinyl chloride-based copolymer is less than the above, it is difficult to obtain a uniform surface coating. The conductivity may be insufficient.

In the present invention, in order to impart conductivity without impairing the hue and transparency of the substrate, the thickness of the conductive coating formed on the surface is preferably 0.01 μm to 20 μm, and more preferably It is 0.05 μm to 5 μm. If the thickness of the coating is less than this, sufficient conductivity cannot be obtained, and if it is too thick, problems such as poor transparency and easy loss of conductivity due to cutting or peeling of the coating during molding occur. Sometimes.

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 carried out to obtain an antistatic effect. It can be further enhanced. Examples of the reducing agent used for the chemical reduction include hydrazine, hydrazine hydrate, hydrazines 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 1 nitrogen atom of the polymer, but is not necessarily limited thereto. In the electrolytic reduction, dedoping is performed by passing a current through the surface of the molded body as a cathode at an applied voltage of 0.01 to several tens V. After the reduction, the neutral conductive polymer film is chemically reoxidized with an oxidizing agent and doped. As the dopant used for such re-doping, any compound having an oxidizing power sufficient for re-oxidizing the reduced neutral polymer and having an electron accepting property effective as a dopant can be used. Examples of such an oxidizing agent 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.

It is also possible to carry out oxidation and doping electrochemically again. In this case, the oxidizing agent may be used as the indicator electrolyte, and the conductive polymer film may be used as the anode to pass an electric current.

[0028]

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

In the following examples, volume conductivity (S / cm) was used as a unit showing conductivity. Further, the adhesion test between the base material and the conductive coating was carried out by leaving the sample at room temperature for 1 week, then cutting it into crevices, strongly pressing the cellophane tape with fingers and peeling it all at once. At this time, the adhesiveness was determined by the number of eyes remaining without peeling.

Example 1 12 g of ferric chloride, 12 mg of ferrous chloride and a vinyl chloride-based vinyl chloride / vinyl acetate / maleic anhydride (70: 29: 1 by weight ratio) copolymer (number average) Degree of polymerization, 23,000) 10 g acetone / toluene / ethyl acetate (weight ratio 5:25:70) mixed solvent 200 g
Dissolved in. This solution is spin coated by
It was coated on a polyvinyl chloride film as a base material. afterwards,
Nitrogen gas was passed through this sample at room temperature in a desiccator,
The solvent was evaporated off. Here, the composition of the polyvinyl chloride film is 100% vinyl chloride resin (degree of polymerization about 800).
Parts, DOP 40 parts, calcium bicarbonate 50 parts, barium stearate 2 parts, and zinc stearate 1.5 parts.

Next, the obtained film was brought into contact with saturated steam at 70 ° C. for 5 minutes, and immediately brought into contact with steam of pyrrole at 30 ° C. for 20 seconds. At this time, the polyvinyl chloride plate was colored yellow, but the transparency was maintained until the end. The sample was thoroughly dried, washed with methanol for 12 hours, and dried under vacuum at room temperature for 24 hours. The conductivity of the surface of the obtained polyvinyl chloride plate was about 10 ⁻⁴ S / cm, which was a sufficient value as an antistatic material. Further, the conductivity did not change significantly with temperature and humidity. After being left for one month, no peeling of the surface coating was observed in a peeling test using a cellophane tape.

Comparative Example 1 A conductive thin film was formed on a polyvinyl chloride film in the same manner as in Example 1 except that polyvinyl acetate (molecular weight 20,000) was used instead of the vinyl chloride copolymer. Formed. The surface of the obtained polyvinyl chloride film had an electric conductivity of about 2 × 10 ⁻⁴ S / cm, and the electric conductivity did not change significantly with temperature and humidity. However,
In a peeling test using cellophane tape, about 20% of the peeling of the surface coating was recognized.

Example 2 A conductive thin film was formed on a substrate in the same manner as in Example 1 except that the substrate used in Example 1 was a corona discharge treated polypropylene film. The conductivity of the obtained polypropylene film surface was about 10 ⁻⁴ S / cm, and the conductivity did not change significantly with temperature and humidity. Further, no peeling of the surface coating was observed in the peeling test using cellophane tape.

Comparative Example 2 A conductive thin film was formed on a polypropylene film in the same manner as in Example 2 except that polyvinyl acetate (molecular weight 20.000) was used in place of the vinyl chloride copolymer. It was The conductivity of the obtained polypropylene film surface was about 10 −4 S / cm, and the conductivity did not change significantly with temperature and humidity. However, in a peeling test using a cellophane tape, 50% or more peeling of the surface coating was recognized.

Comparative Example 3 A conductive thin film was formed on a polypropylene film in the same manner as in Example 2 except that polymethyl methacrylate (molecular weight 30,000) was used in place of the vinyl chloride copolymer. It was The conductivity of the surface of the obtained polypropylene film was about 10 ⁻⁴ S / cm, and in this case as well, 50% or more peeling of the surface coating was observed in the peeling test using cellophane tape.

Example 3 In Example 1, the base material was a polycarbonate (Panlite L-1250 (trade name) manufactured by Teijin Chemicals Ltd.).
A conductive thin film was formed on the substrate in the same manner as in Example 1 except that the film was used. The conductivity of the surface of the obtained polycarbonate plate was about 10 ⁻⁴ S / cm, and the conductivity did not change significantly with temperature and humidity. Further, no peeling of the surface coating was observed in the peeling test using cellophane tape.

Example 4 In Example 1, the temperature of the pyrrole vapor was set to 70 ° C.,
A conductive thin film was formed on the base material in the same manner as in Example 1 except that the contact time with the base material coated with the vinyl chloride copolymer containing an oxidizing agent was 15 seconds. The electric conductivity of the obtained film surface was about 7 × 10 ⁻⁴ S / cm, and the electric conductivity did not change significantly with temperature and humidity. Further, no peeling of the surface coating was observed in the peeling test using cellophane tape.

Example 5 In Example 1, a vinyl chloride / vinyl propionic acid (70:30 by weight ratio) copolymer was used as the vinyl chloride copolymer and toluene / ethyl acetate (30% by weight ratio) was used as the solvent. : 70) A conductive thin film was formed on a substrate in the same manner as in Example 1 except that the mixed solvent was used. The electric conductivity of the obtained film surface was about 2 × 10 ⁻⁴ S / cm, and the electric conductivity did not change significantly with temperature and humidity. Further, no peeling of the surface coating was observed in the peeling test using cellophane tape.

Example 6 The conductive polyvinyl chloride plate prepared in Example 1 was dipped in a solution of 200 mg of phenylhydrazine in 10 ml of ether and reacted at room temperature for 1 hour while stirring. After the reaction, the film was washed with ether and dried under vacuum. This film was oxidatively doped by exposing it to iodine vapor for 10 hours in a desiccator at room temperature. The surface conductivity of this polyvinyl chloride plate was measured and found to be 0.2 S / cm.
It was confirmed that the conductivity increased.

[0040]

According to the present invention, conductivity can be easily imparted to the surface of a synthetic resin substrate. At this time, if the conductive layer on the surface is made thin, the transparency and hue of the original material are not significantly impaired. In addition, the obtained conductivity lasts for a long time and is hardly affected by temperature and humidity. Therefore, the method of the present invention is an anti-electrostatic material for preventing damage due to static electricity of semiconductors or explosion accident due to discharge in the fields of electronic / electrical products and building materials, or an electromagnetic wave for preventing the influence of external electromagnetic waves on precision machinery. It is extremely useful in manufacturing shield materials.

Claims (7)

[Claims] 1. A surface of a synthetic resin substrate comprising one or more compounds selected from a vinyl chloride copolymer having a vinyl chloride chain content of 5 to 95% by weight, a heterocyclic compound, and an aniline compound. A conductive composite formed by forming a conductive composite coating made of a polymer. 2. A vinyl chloride-based copolymer comprising vinyl esters, vinyl ethers, unsaturated dicarboxylic acids, unsaturated dicarboxylic acid anhydrides, unsaturated dicarboxylic acid imidized products, acrylic acid derivatives, methacrylic acid derivatives, and vinyl heterocycles. The conductive composite according to claim 1, comprising a constituent component derived from at least one or more kinds of monomers selected from compounds. 3. The conductive composite according to claim 1, wherein the heterocyclic compound is a compound selected from pyrrole compounds, furan compounds and thiophene compounds. 4. A synthetic resin substrate coated with a vinyl chloride-based copolymer containing an oxidizing agent is contacted with vapor of at least one compound selected from a heterocyclic compound and an aniline-based compound, and the surface portion of the substrate is contacted. In the method for producing a conductive coating, a vinyl chloride-based copolymer contains 5 to 95% by weight of a vinyl chloride chain and an oxidizer in an amount of 5 to 50% by weight. Method. 5. A vinyl chloride-based copolymer comprising vinyl esters, vinyl ethers, unsaturated dicarboxylic acids, unsaturated dicarboxylic acid anhydrides, unsaturated dicarboxylic acid imidized products, acrylic acid derivatives, methacrylic acid derivatives and vinyl heterocycles. The method for producing a conductive composite according to claim 4, comprising a constituent component derived from at least one kind of monomer selected from compounds. 6. The method for producing a conductive composite according to claim 4, wherein the heterocyclic compound is a compound selected from pyrrole compounds, furan compounds and thiophene compounds. 7. The oxidizing agent is an iron (III) salt, a molybdenum (V) salt or a ruthenium (III) salt.
The method for producing a conductive composite as described in 1.