JPH0657445B2 - Conductive composite - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (1) Background of the Invention The present invention relates to a conductive composite having an excellent balance between transparency or coloring and conductivity.

In recent years, along with the development of electrical and electronic devices, there is a strong demand for development of materials to which conductivity is added in addition to characteristics such as moldability and strength of plastics.

In response to this, plastic materials in which conductivity is imparted by kneading plastics with carbon black, metal fibers, graphite, etc. are being put to practical use.

However, these are not applicable to applications requiring transparency due to being colored in black or applications other than black.

On the other hand, the demand for a conductive plastic material having transparency or colorability has become stronger and stronger as the development of electrical and electronic devices and systems utilizing the phenomenon involving both light and electricity. . In addition, there is a strong demand for the development of packaging materials that have antistatic properties and through which the items to be packaged can be seen through, or the development of plastic molding materials that can develop colorful colors and have antistatic properties. There is.

Conventionally, as a transparent and conductive material, a material obtained by vacuum-depositing tin oxide, indium oxide, etc. on a glass substrate has been used. However, since the substrate is made of glass, it is difficult to form a thin film and have a large area, and flexibility and mechanical strength are weak, so that it is limited to a very limited number of applications such as a display.

As a solution to these problems, a film in which tin oxide, indium oxide, gold, palladium or the like is vacuum-deposited on a polyester film has been developed. These are in terms of the balance of transparency and conductivity, thinning,
It has a large area, is flexible, and has excellent mechanical strength.

However, when tin oxide, indium oxide, gold, palladium, etc. are used as vapor deposition materials, the evaporation temperature is high, or the temperature of the vapor-deposited polymer film surface rises due to the condensation heat of metal vapor and inorganic semiconductor vapor. Therefore, the base polymer film is limited to a polymer film having excellent heat resistance.

Further, since gold, palladium and the like are very expensive materials, the cost of the vapor deposition film obtained is very high.

Further, in recent years, conductive polymers such as polyacetylene, polypyrrole, and polythiophene have been extensively researched, but they are black and have poor transparency and coloring properties like polyacetylene, and these conductive polymers are also available. Requires doping of an electron donor or electron acceptor called a dopant, but the stability of the composite of this dopant and the conductive polymer is poor, and the deterioration of the conductive performance due to long-term use in air is avoided. It was not done.

(2) Summary of the invention In view of such a current situation, the present inventors, without using expensive gold, palladium, etc., also, it is possible to relatively widely select the polymer material of the base material, and stable expression of conductive performance The present invention has been achieved as a result of earnest efforts to develop a conductive composite material having a good balance with transparency or colorability.

That is, the present invention is based on a polar organic polymer compound,
The following (1) having a number average molecular weight of 300 to 500,000 on the substrate
The present invention provides a conductive composite characterized by being formed into a composite by forming an aromatic vinylene sulfide polymer layer having a formula as a repeating unit.

R _{1 to} R ₈ in the formula (1) are hydrogen, halogen, and 1 to 12 carbon atoms.
Represents a group selected from the alkyl groups of. R _{1 to} R ₈
Is preferably hydrogen, an alkyl group having 1 to 5 carbon atoms, or halogen.

(3) Detailed Description of the Invention The number average molecular weight of the aromatic vinylene sulfide polymer having the repeating unit of the above formula (1) (hereinafter, abbreviated as aromatic vinylene sulfide polymer) is the ethynyl group or thiol group at the molecular end. It can be determined by a method of metal-complexing a group and quantifying the metal, or by vapor pressure osmometry (VPO). The number average molecular weight of the aromatic vinylene sulfide polymer used in the present invention is 300 to 500,000, preferably 700 to 300,000, more preferably 1,000 to 100,000, and particularly preferably 2,000 to 80,000.

The aromatic vinylene sulfide polymer may be a crystalline aromatic vinylene sulfide polymer in which crystals are observed by an X-ray method, or may be an amorphous aromatic vinylene sulfide polymer. .

In the case of a crystalline aromatic vinylene sulfide polymer, for example, an aromatic vinylene sulfide polymer layer in which R _{1 to} R ₄ and R _{5 to} R _{8 of the} formula (1) are all H is formed on a polyester substrate. In that case, the conductivity is 10 ⁻⁵ s / cm.

Even when a polar organic polymer compound is used as the base material and an amorphous aromatic vinylene sulfide polymer is grown on this base material, the conductivity without doping of the aromatic vinylene sulfide polymer layer is obtained. Can be expressed sufficiently higher than conventionally known organic conductive polymers. On the other hand, when glass, amorphous Si, Al crystals, etc. are used for the base material, the conductivity of the aromatic vinylene sulfide polymer layer composited on the base material is It is much lower than when a polar organic polymer compound is used as the material.

The present invention improves the conductivity of an aromatic vinylene sulfide polymer layer composited on a substrate by using a polar organic polymer compound as compared to the case where glass, amorphous silicon or the like is used as a substrate. To do.

As the polar organic polymer compound used as the substrate, polyester, polyether, polyamide, polyimide,
Organic polymer compounds having polar groups such as polycarbonate, polymethylmethacrylate, polyparaphenylene sulfide, polyvinyl alcohol, acrylonitrile resin, poly (vinyl halide), poly (vinylidene halide) are used.

Further, a non-polar organic polymer compound may be subjected to a polarization treatment, and the polar organic polymer compound may be used on the surface of the base material which is in contact with the aromatic vinylene sulfide. Therefore, it is possible to use a molded product formed by molding a non-polar organic polymer compound and subjecting its surface to a polarization treatment with a polar compound or oxygen.

Further, in order to sufficiently maintain the adhesive force between the base material and the aromatic vinylene sulfide polymer, the surface free energy of the base material ▲ γ
^{(20 ℃)} _S ▼ is 28 dyne / cm ² or more, preferably 30 dyne / cm
^It is preferable to select a substrate having a density of ² or more, more preferably 35 dyne / cm ² or more.

Polyethylene terephthalate and polyacrylonitrile are particularly preferable.

As the shape of the base material, an arbitrary shape such as a film shape, a sheet shape, a filler shape, or a fiber shape is selected depending on the intended use.

The aromatic vinylene sulfide polymer used in the present invention can be obtained by addition polymerization of both monomers having the structures represented by the following structural formulas (2) and (3).

R _{1 to} R ₈ in the formulas (2) and (3) are hydrogen, halogen, and a carbon number of 1.
~ 12 alkyl groups. Preferably hydrogen, carbon number 1
~ 5 alkyl groups, halogen.

Examples of the compound represented by the above structural formula (2) include P-diethynylbenzene, m-diethynylbenzene, and diethynyltoluene.

Examples of the compound represented by the structural formula (3) include P-benzenedithiol, m-benzenedithiol, 4-chloro-m-
For example, benzenedithiol.

The reaction is carried out by irradiating a mixture of both monomers represented by the structural formulas (2) and (3) with active light (visible light, ultraviolet light, electromagnetic waves such as γ rays and X rays, electron rays, etc.) or benzoyl peroxide. An aromatic vinylene sulfide polymer can be obtained by adding a radical generator such as the above or in the presence of a trace amount of oxygen.

The reaction is from −80 ° C. to 200 ° C., preferably −50 ° C.
It is carried out at 150 ° C, more preferably -20 ° C to 100 ° C. In particular, in order to obtain crystals of the aromatic vinylene sulfide polymer, a temperature below the melting point of the mixed vapor deposition monomer crystals is selected.

The composite of the base material and the aromatic vinylene sulfide polymer is carried out by the following method.

First, a method suitable for forming a crystalline aromatic vinylene sulfide polymer layer on a substrate will be described.

Monomers of the structural formulas represented by the above formulas (2) and (3) are simultaneously sublimated to form a mixed monomer vapor deposition film on a substrate. This mixed monomer vapor deposition film can form good quality crystals. Moreover, the crystal structure may differ depending on the type of the substrate. Solid phase addition polymerization is performed by irradiating the mixed monomer vapor deposition film on the base material with actinic rays to form a crystal layer of the aromatic vinylene sulfide polymer on the base material.

The X-ray diagram of the crystal of the aromatic vinylene sulfide polymer compounded on the substrate shows an X-ray diagram very similar to that of the mixed monomer vapor deposition film.

From this fact, the crystal structure of the aromatic vinylene sulfide polymer is formed differently depending on the type of the base material, but it is considered that the organic polymer compound has an action to make the crystal structure advantageous for conductivity. .

Further, the amorphous aromatic vinylene sulfide polymer can be compounded on the substrate by the same method as described above. That is, solid-phase addition polymerization is performed at a temperature equal to or higher than the melting point of the mixed vapor-deposited monomer crystal, or the above-mentioned composite is performed using a specific organic polymer base material, or the aromatic vinylene sulfide polymer formed on the base material. This is a method of subjecting the combined crystal to a heat treatment at a certain temperature or higher or irradiating with light of a specific wavelength to cause a phase transition to an amorphous aromatic vinylene sulfide polymer.

Further, after applying a solution of a mixture of monomers of structural formulas (2) and (3) onto the substrate by a method such as spin coating, blade coating, dipping, casting, or spraying,
Both monomer mixtures can be combined on the substrate by drying. The amorphous aromatic vinylene sulfide polymer can also be composited on the base material by carrying out solid phase addition polymerization by irradiating this with active light.

INDUSTRIAL APPLICABILITY The present invention can use an organic polymer compound having excellent transparency such as polyester as a substrate and is suitable for obtaining a conductive composite having excellent transparency. Further, by using a polar organic polymer compound as a base material, an aromatic vinylene sulfide polymer compounded with high conductivity can be obtained, and flexibility, mechanical strength, shapeability and transparency are improved. Thus, the excellent conductive composite of the present invention can be obtained.

Furthermore, the aromatic vinylene sulfide polymer layer of the present invention has relatively high transparency despite its high conductivity, so that the contents can be seen through even when it is used as a packaging material, and it is colorful. It can also be used as a simple molding material.

In addition, the above-mentioned conductivity is achieved without using a treatment such as doping, does not change even when used for a long period of time, and has excellent transparency and quality stability.

Hereinafter, the present invention will be specifically described with reference to examples.

[Example 1] A polyethylene terephthalate sheet (density 1.455 g / cc, lattice constant 3.44, surface energy (20 ° C) 43.8 dyne / cm ² ) that had been thoroughly washed with purified ether in a sublimation apparatus in advance.
Was set as a substrate, and 0.134 g of an equimolar mixture of powder crystals of P-diethynylbenzene and P-benzenedithiol was added. The vacuum of the deposition chamber was set to 0.5 mmHg by the exhaust operation. Further, the evaporation source was heated to 60 ° C. and sublimated for 30 seconds to form a vapor-deposited crystal thin film (thickness 10.4 μm) of a mixed monomer of P-diethynylbenzene and P-benzenedithiol on a polyethylene terephthalate substrate. The crystal of this mixed monomer vapor deposition film has the maximum diffraction peak in X-ray diffraction at d = 7.73Å, further d = 7.5Å, and further 3.90.
There are two peaks at Å and 3.6 to 3.8 Å, and diffraction peaks at 2.60 Å and 1.95 Å. FIG. 1 shows the relative intensity based on the height of the maximum diffraction peak.

The mixed monomer crystal thin film of P-diethynylbenzene and P-benzenedithiol thus obtained on the polyethylene terephthalate substrate was kept at 60 ° C. and irradiated with ultraviolet rays for 12 minutes by a high pressure mercury lamp (300 W). After the ultraviolet irradiation, the above crystal thin film was washed with methanol to remove the residual monomer, but the polymerization was performed at a yield of 91%.

The X-ray diffraction pattern of the addition polymer crystal of P-diethynylbenzene and P-benzenedithiol thus obtained on the PET substrate was very similar to that of the mixed monomer vapor deposition crystal.

The number average molecular weight of the above polymer is 400 by the copper acetylide method.
It was 0. In addition, the composition of the above-mentioned polymer was determined by a flask combustion method [organic trace quantitative analysis page 383 (1969) Nankodo].
It was found to be 22.3 wt% by analyzing sulfur. Furthermore, PET
The conductivity of the above polymer on the substrate was 4.5 × 10 ⁻⁵ s / cm as measured by the platinum electrode two-terminal method.

The polymer on the PET substrate showed absorption at 200 to 500 nm and had a yellowish color tone, but was transparent enough to be seen through. In the diffuse reflection spectrum of the above polymer, the absorbance at a wavelength of 500 nm was about 0.2 to 0.3.

Further, the adhesive force between the PET substrate and the polymer was strong enough not to easily peel off.

Example 2 Instead of a PET sheet as a substrate, a polyacrylonitrile sheet (lattice constant 5.27Å, surface free energy (20
℃) = 52.3dyne / cm ²⁾ except for using, all Example 1
On the polyacrylonitrile sheet in the same manner as
A mixed monomer vapor-deposited crystal thin film (thickness 10.6 μm) of diethynylbenzene and P-benzenedithiol was formed. The X-ray diffraction pattern of the crystals of this mixed monomer vapor deposition film is shown in FIG. 2 with the relative intensity based on the height of the maximum diffraction peak. PET
Compared with the one obtained when the sheet is used as the substrate (FIG. 1), it is significantly different and shows the strength of dependence on the substrate.

The mixed monomer crystal thin film of P-diethynylbenzene and P-benzenedithiol thus obtained on the polyacrylonitrile substrate was polymerized in the same manner as in Example 1 to obtain an addition polymer in a yield of 90%.

The X-ray diffraction pattern of the crystals of the above-mentioned addition polymer thus obtained on the polyacrylonitrile substrate was very similar to that of the mixed monomer vapor-deposited crystals.

The number average molecular weight of the above polymer is 300 by the copper acetylide method.
It was 0. The sulfur content in the polymer was 23.8 wt%. The conductivity of the above polymer on the polyacrylonitrile substrate was measured in the same manner as in Example 1, and was 1.4 × 10 ⁻⁶ s.
It was / cm.

The color tone and transparency of the above polymer on the polyacrylonitrile substrate were similar to those of the polymer of Example 1.

Also, the adhesion between the polyacrylonitrile substrate and the above polymer was very strong.

Example 3 All were the same as Example 1 except that polyoxymethylene having a density of 1.49 g / cc, a lattice constant of 3.84Å and a surface free energy of ▲ γ ^{(20 ° C.)} _S ▼ = 44.6 dyne / cm ² was used as the substrate. And then
An addition polymer of P-diethynylbenzene and P-benzenedithiol was compounded.

The X-ray diffraction pattern of the crystal of the mixed monomer vapor deposition film of P-diethynylbenzene and P-benzenedithiol vapor-deposited on the polyoxymethylene substrate is shown in FIG. 3 with the relative intensity based on the height of the maximum diffraction peak. .

Further, when the mixed monomer vapor deposition film was polymerized in the same manner as in Example 1, an addition polymer was obtained with a yield of 92%. The addition polymer thus obtained on the polyoxymethylene substrate was completely non-polymerized. It was crystalline.

The number average molecular weight of the above polymer is 5000 according to the copper acetylide method.
Met. The sulfur content in the polymer was 23.7 wt%. The conductivity of the above polymer on the polyoxymethylene substrate was measured in the same manner as in Example 1, and was 3.2 × 10 ⁻⁸ s / cm.
Met.

The polymer on the polyoxymethylene substrate is 20
It showed absorption at 0 to 500 nm and had a yellowish color tone, but was transparent enough to be seen through. In the diffuse reflection spectrum of the above polymer, the absorbance at a wavelength of 500 nm was about 0.1 to 0.2.

The adhesive strength between the polyoxymethylene substrate and the addition polymer was very strong.

Comparative Example 1 A glass (amorphous, surface free energy ▲ γ
An addition polymer of P-diethynylbenzene and P-benzenedithiol was compounded in the same manner as in Example 1 except that ^{(20 ° C.)} _S ▼ = 300 dyne / cm ² ) was used.

P-diethynylbenzene and P- deposited on a glass substrate
The X-ray diffraction pattern of the crystal of the mixed monomer vapor deposition film of benzenedithiol is shown in FIG. 4 with the relative intensity based on the height of the maximum diffraction peak.

In addition, the mixed monomer vapor deposition film was polymerized in the same manner as in Example 1 to obtain an addition polymer with a yield of 90%. The X-ray diffraction pattern of the crystal of the addition polymer thus obtained on the glass substrate was very similar to that of the mixed monomer vapor-deposited crystal. The number average molecular weight of the above polymer was 3000 by the copper acetylide method. The sulfur content in the polymer was 24.0 wt%. The conductivity of the above polymer on the glass substrate was measured in the same manner as in Example 1 to be 1.5 × 10 ^−10.
It was as low as s / cm. The color tone and transparency of the above polymer were similar to those of the polymer of Example 1.

The adhesive strength between the glass substrate and the addition polymer was strong.

Comparative Example 2 The addition polymer crystals of diethynylbenzene and benzenedithiol, which were composited on the glass substrate obtained in Comparative Example 1, were used.
Heat treatment was performed at 0 ° C. for 1 hour. Thus, the above-mentioned polymer crystals on the glass substrate became completely amorphous polymers as seen from the X-ray diffraction pattern.

The conductivity of the amorphous polymer on the glass substrate is shown in Example 1.
When measured in the same manner as in ^{Example 1,} it was as low as 1.4 × 10 ^-10 s / cm.

The color tone and transparency of the above amorphous polymer were similar to those of the polymer of Example 4.

Comparative Example 3 Example 1 except that Amorphis Si was used as the substrate.
In the same manner as above, an addition polymer of P-diethynylbenzene and P-benzenedithiol was compounded.

The X-ray diffraction pattern of the crystal of the mixed monomer vapor deposition film of P-diethynylbenzene and P-benzenedithiol vapor-deposited on the Amorphis Si substrate is shown in FIG. 5 with the relative intensity based on the height of the maximum diffraction peak.

In addition, the mixed monomer vapor deposition film was polymerized in the same manner as in Example 1 to obtain an addition polymer with a yield of 93%. The X-ray diffraction pattern of the crystal of the addition polymer thus obtained on the Si substrate was very similar to the X-ray diffraction pattern of the mixed monomer vapor deposition crystal. The number average molecular weight of the above polymer was 1,000 by the copper acetylide method. The content of sulfur in the above polymer is
It was 17.0 wt%. The conductivity of the above polymer on the Si substrate was measured in the same manner as in Example 1 and was as low as 3.2 × 10 ⁻¹⁰ s / cm. Further, the color tone and transparency of the above polymer were similar to those of Example 1 weight body.

[Brief description of drawings]

1 to 5 show the relative intensities of the X-ray diffraction peaks of the polar organic compound films formed on the substrate in Example 1, Example 2, Example 3, Comparative Example 1 and Comparative Example 3, respectively. FIG.

Claims (2)

[Claims] 1. A composite comprising a polar organic polymer compound as a base material, and an aromatic vinylene sulfide polymer layer having a number average molecular weight of 300 to 500,000 and having the following formula (1) as a repeating unit formed on the base material. An electrically conductive composite, characterized in that 2. The surface free energy ▲ γ ^{(20 ° C.)} _S ▼ is 30d.
The conductive composite according to claim 1, wherein a polar organic polymer compound having a yne / cm ² or more is used as a base material.