JPH08287726A - Conductive composite material and high frequency circuit board - Google Patents

Abstract

PURPOSE: To provide excellent properties by forming a conductive semiconductor film on a polymer sheet or film consisting of tetracyclododecene and norbornene in specified amounts. CONSTITUTION: A ring-opening polymer consisting of 50-100 mole% of tetracyclododecene or its derivative and 0-50 mole% of norbornene or its derivative is hydrogenated to give a polymer. The hydrogenation reaction is carried out in hydrogen at 1-150 atmospheric pressure in 0-180 deg.C, preferably 20-100 deg.C in a uniform system or an un-uniform system. A ring-opening polymer hydrogenated material with high organic solvent resistance and high humidity resistance is obtained by hydrogenating at least 80%, preferably at least 90% and more preferably at least 95%, of unsaturated bonds in the ring-opening polymer main chain. A transparent conductive film having high light transmittance and photo resistance stability can be obtained by utilizing a polymer produced from methyltetracyclododecene and methylnorbornene shown as the formula I, II in the presence of ruthenium chloride.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conductive composite material which is particularly preferably used for transparent conductors and high frequency circuit boards.

[0002]

2. Description of the Related Art A polymer film or sheet provided with a conductive film on the surface thereof, which is entirely transparent, is useful as a transparent conductor. That is, transparent conductors are used in transparent electrodes of various display elements such as liquid crystal display elements and electroluminescence display elements, and resistance heating elements used in anti-fog window glasses of automobiles and aircraft.

By the way, most of the transparent conductors that have been conventionally used are those in which a metal oxide transparent conductive film such as a tin oxide film or an indium oxide film is formed on a glass substrate. However, there is a limit to the large area of glass, and the thickness can only be thinned to about 0.3 mm, the weight is heavy, it is brittle and fragile, the workability such as punching and cutting is bad, and continuous productivity is high. But there are drawbacks.

Therefore, in recent years, a transparent conductive film using a polymer film or sheet (hereinafter, both are abbreviated as a film) as a substrate instead of glass has been developed. The transparent conductive film using this polymer film as a substrate is thin, light, does not break, is flexible, has good processability, can be made into a large area, and has excellent continuous productivity. It has features. A polyester film such as polyethylene terephthalate is known as a polymer film used as a substrate for the transparent conductive film. However, the polyester film is easily attacked by a strong acid or a strong alkali and may absorb water to cause hydrolysis.
Especially when a transparent conductive film is used for a display application, it is necessary to pattern the conductive film into a predetermined shape, and a photo-etching method has been conventionally used. As such, the lack of alkali resistance is a serious drawback. Further, when forming a thin film by a vacuum vapor deposition method or a sputtering method, it is difficult to raise the degree of vacuum of water in the polyester, and it takes a long time to reach the desired degree of vacuum, resulting in poor productivity. There is a problem that makes it difficult to control the degree of oxidation.

Another application of the composite material in which a conductive film is provided on the surface of a polymer film is an electric circuit board, and there are particular expectations for an electric circuit board for high frequencies.
That is, when an electromagnetic wave is used for communication, a wider frequency band can be obtained by using a higher frequency wave, and thus a larger amount of information can be transmitted. Further, as the frequency becomes higher, the wavelength becomes shorter in inverse proportion to it, and as a result, there is an advantage that a small size and high performance antenna can be manufactured.

By the way, a substrate having a low dielectric constant and a low dielectric loss and high heat resistance is required for a substrate of an electric circuit for such a high frequency. That is, at high frequencies, the propagation speed of an electric signal becomes faster as the inductivity of the circuit board becomes smaller, and the attenuation of the electric signal becomes smaller as the dielectric loss of the circuit board becomes smaller. Therefore, a material having a smaller dielectric constant and dielectric loss can achieve higher speed and higher SN. Also, in the process of manufacturing the electric circuit, 2
Since a temperature exceeding 00 ° C is applied, heat resistance is required so as not to deform even under such a temperature.

Under these circumstances, substrates using various materials are currently proposed, for example, substrates made of fluororesin, epoxy resin, polyimide, polypropylene or the like. However, there are problems that the fluororesin has poor adhesion to the metal that forms the conductive layer, has low rigidity, and is extremely expensive. Epoxy resin or polyimide has been conventionally used as a circuit board for low frequency and medium frequency, but it is not suitable for use for high frequency because its dielectric constant and dielectric loss are too large. Polypropylene has excellent dielectric constant and dielectric loss, but lacks heat resistance and is apt to be deformed.

As described above, conventionally proposed high frequency electric circuits also have advantages and disadvantages, and none have been known to exhibit excellent performances in all aspects.

[0009]

DISCLOSURE OF THE INVENTION Therefore, the inventors of the present invention have a transparent conductive film excellent in mechanical properties, optical properties, electrical properties, thermal properties, and chemical properties, and an electric circuit suitable for high frequencies. As a result of studying that a substrate is not provided, it was found that the purpose can be achieved by using a specific polymer as a base material.

[0010]

That is, according to the present invention, a ring-opening polymer comprising tetracyclododecene or its derivative: 50 to 100 mol% and norbornene or its derivative: 0 to 50 mol% is subjected to a hydrogenation reaction. It is a conductive composite material characterized in that a conductive semiconductor film, an oxide semiconductor film or a multilayer film is provided on the surface of a stretched or unstretched sheet or film of the polymer obtained as described above.

Further, the present invention is directed to stretching of a polymer obtained by hydrogenating a ring-opening polymer comprising tetracyclododecene or its derivative: 50 to 100 mol% and norbornene or its derivative: 0 to 50 mol%. Alternatively, the high-frequency circuit board is made of a conductive composite material in which a conductive organic film, an inorganic film, a semiconductor film, an oxide semiconductor film, or a multilayer film is provided on the surface of an unstretched sheet or film.

[0012]

The polymer constituting the sheet or film (hereinafter abbreviated as film) which is the substrate of the conductive composite material of the present invention is a homocyclic ring-opening polymer of tetracyclododecene or its derivative or tetracyclododecenes. It comprises a polymer obtained by hydrogenating a ring-opening polymer of norbornene or a derivative thereof with a ring-opening copolymer. Therefore, in the skeleton of the polymer, substantially no unsaturated bond based on ring-opening polymerization is contained, and thus chemical resistance, solvent resistance, oil resistance and heat resistance as compared with the polymer before hydrogenation, Shows excellent weather stability.

As the raw material monomer for the hydrogenated polymer, a commercially available product may be used, but a miscellaneous monomer contained in the commercially available product may hinder the polymerization of the intended polymer, so that it is necessary. It is preferably purified. Also, especially tetracyclododecenes may be difficult to obtain, so
In that case, U.S. Pat. No. 3,557,072, Japanese Patent Publication No. 46-
It may be synthesized by the method disclosed in Japanese Patent Publication No. 14910, Japanese Patent Laid-Open No. 57-154133, or the like.

A technique for producing a ring-opening polymer by polymerizing tetracyclododecenes and norbornenes is already known, and disclosed in, for example, Japanese Patent Publication No. 46-14910 and Japanese Patent Publication No. 58-127728. It is possible to adopt the method that is used. The ratio of tetracyclododecenes in the ring-opening polymer is usually 50 mol% from the viewpoint of heat resistance.
Above, especially 70 mol% or more is preferable. The proportion of norbornenes in the ring-opening polymer is usually less than 50 mol%, particularly less than 30 mol%. For the molecular weight, see
It is adjusted by adding olefins as shown in JP-A-8-127728.
It is 10,000, preferably 10,000 to 500,000. Further, the melt flow index MFR (260 ° C., which is an index of fluidity,
2.16 kg) is 0.001-1000, preferably 0.1.
05-200, particularly preferably 0.1-100 g / 10 m
The range of in.

The hydrogenation reaction of the ring-opening polymer is carried out by an ordinary method, and depending on the type of catalyst, it may be a homogeneous system or a heterogeneous system.
Under hydrogen pressure of 150 atm, 0 to 180 ° C, preferably 20
It is performed in a temperature range of -100 ° C. And by changing the hydrogen pressure, reaction temperature, reaction time, catalyst concentration, etc.,
The hydrogenation rate can be adjusted arbitrarily.

The hydrogenation catalyst may be any as long as it is used in the hydrogenation of an olefin compound. For example, a heterogeneous catalyst may be nickel, palladium, platinum, or a metal thereof such as carbon, silica or diatom. Examples thereof include catalysts supported on a carrier such as soil, alumina and titanium oxide, that is, nickel / silica, nickel / diatomaceous earth, palladium / carbon, palladium / silica, palladium / diatomaceous earth and palladium / alumina. The homogeneous catalysts include nickel naphthenate / triethylaluminum, cobalt octenoate / n-butyllithium, nickel acetylacetonate / triethylaluminum, etc., nickel compounds, cobalt compounds and organometallic compounds of Group I to III metals And Rh compounds and the like.

In order for the hydrogenated product of the ring-opening polymer to exhibit the above-mentioned various excellent properties, the unsaturated bond portion in the main chain of the polymer is 80
% Or more, preferably 90% or more, in particular 95% or more, should be hydrogenated. The hydrogenation rate is 80% or more, especially 9
When it is 0% or more, the polymer has a solubility parameter (SP value) different from that of the polymer before hydrogenation, and the effect of improving the organic solvent resistance is also exhibited. Further, from the viewpoint of moisture resistance, it is desirable that the hydrogenated product has no polar group.

In order to produce a film as a base material, the ring-opening polymer hydrogenated product can be formed by various known methods such as extrusion, injection, compression and wet casting. At the time of this molding, various compounding agents usually used for resins may be added if necessary. Further, the obtained film may be subjected to a stretching treatment such as uniaxial stretching, simultaneous biaxial stretching or sequential biaxial stretching to further enhance the strength and the like.

When a film is produced by using the hydrogenated ring-opening polymer as a raw material, a uniform transparent film is obtained without decomposition and gelation. These usually show a light transmittance of 85% or more, and most of them show a light transmittance of 90% or more.

For high frequency substrate applications which do not require transparency, unless the properties of the polymer are impaired, 50
You may blend the polyolefin (polyethylene, polypropylene, poly-4-methylpentene-1, etc.) of wt% or less beforehand.

In the conductive composite material according to the first aspect, In ₂ O ₃ (Sn) and SnO ₂ (S are used as the conductive film.
b), SnO ₂ (Fe), CdO, Cd ₂ O ₃ , CdSn
A semiconductor film such as O ₄ , TiO ₂ , ZrO ₂ , or CuI or an oxide semiconductor film or TiOx / Ag / TiOx (x
A multilayer thin film such as ≦ 2) is used.

In the high frequency circuit board according to the fourth aspect, the conductive film is not necessarily transparent, and a conductive organic film, metal film, semiconductor film, oxide semiconductor film or multilayer film is used.

These conductive films are adhered as a sheet, a film or a foil, or laminated on the film by means of plasma polymerization, sputtering, vapor deposition, plating or the like.
For example, when used for a high-frequency circuit board, this conductive film can take the form of a composite layer of usually only the front surface, two layers of the front surface and the back surface, and three or more layers formed inside. The circuit can be formed by various known lithography methods, for example, an etching method. Also,
As another method, a paint comprising a polymer component containing the polymer of the present invention or an unsaturated carboxylic acid modified product of the polymer of the present invention and a conductive material (metal, organic substance) is formed (conductive paint), and a screen is formed. A circuit can be formed by a printing method or the like. Of course, after forming the circuit of conductive paint,
Furthermore, a higher conductive circuit can be formed by a method such as electroless plating.

Further, an adhesive layer may be interposed between the polymer layer and the conductive film (metal, polymer, organic material, conductive paint, etc.). Examples of the adhesive layer include heat resistant resins such as epoxy resin, polyimide, polybutadiene, phenol resin, and polyether ether ketone. Of these, polyimide and epoxy resins are preferable because they are excellent in heat resistance, dielectric properties at high frequencies, and adhesiveness to metals. When interposing such an adhesive layer, it should be noted that the dielectric properties of the circuit board depend on the thickness ratio of the polymer layer and the adhesive layer. That is, in the case of (thickness of polymer layer) <(thickness of adhesive layer), the dielectric property of the circuit board is largely affected by the dielectric property of the adhesive layer and deteriorates as a whole. Of course, depending on the application, for example, a high frequency is targeted, and in a case where the dielectric property is not a strict requirement but rather the adhesive strength with the conductive film on the surface layer is required, the thickness of the adhesive layer is relatively large. It doesn't matter. However, in order to exhibit good dielectric properties for high frequencies, it is preferable that the ratio of the thickness of the polymer layer / the thickness of the adhesive layer is 2 or more, particularly 3 or more. Further, this thickness ratio can be applied to the total thickness of each layer also in the case of a plurality of laminated bodies described later.

Alternatively, a high molecular weight polymer ([η] of 0.3 or more) constituting the substrate as an adhesive layer and the polymer containing α, β-unsaturated carboxylic acid, or an anhydride thereof, It is preferable to use a graft-copolymerized ester or the like because it does not change the dielectric properties of the substrate.

As another embodiment of the present invention, a heat-resistant and insulating fibrous material may be mixed as a reinforcing material in the polymer layer and / or the adhesive layer. Examples of such reinforcing fibrous substances include quartz fibers, glass fibers, aromatic polyamide fibers, short fibers such as high-strength and high-elasticity polyethylene fibers, knitted fabrics, and non-woven fabrics.

As another aspect, the circuit board may be formed in the form of a laminate in which a plurality of polymer layers and adhesive layers are combined.
In this case, each layer may be preferably laminated in the range of 2 to 30 layers. If necessary, the fibrous material may be mixed in each layer or a part of the layers as described above.

As a further embodiment, the polymer layer may be crosslinked with a crosslinking agent. The cross-linking agent forms a three-dimensional structure by heating, irradiation with radiation, etc., and further improves the thermal properties and dimensional stability of the polymer layer. Various known crosslinking agents can be used, and examples thereof include divinylbenzene, diallyl phthalate, ethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, triallyl isocyanurate, and liquid polybutadiene.

When the composite material of the present invention is used as a transparent conductive sheet, the visible light transmittance of the conductive film, that is, the value measured according to JIS K 6714 is 50% or more, particularly 70% or more, and the specific resistance is Is 100 Ωcm or less, especially 50 Ωcm or less. More specifically, In
₂ O ₃ (Sn), SnO ₂ (Sb), SnO ₂ (Fe), C
dO, Cd ₂ O ₃ , CdSnO ₄ , TiO ₂ , ZrO ₂ , C
semiconductor films such as uI and oxide semiconductor thin films, TiOx
Examples thereof include multilayer thin films such as / Ag / TiOx (x ≦ 2).

In the high frequency circuit board according to the present invention,
As an electrically conductive film, transparency is not particularly required, but specific resistance is
Use less than 100Ωcm, especially less than 50Ωcm
Is preferred. More specifically, Au, Ag, Cu, P
t, Al, Cr, Rh, and other metal thin films, In₂O₃(S
n), SnO₂(Sb), SnO₂(Fe), CdO, C
d ₂O₃, CdSnO_Four, TiO₂, ZrO₂, CuI, etc.
Semiconductor film and oxide semiconductor thin film, TiOx / Ag /
Multi-layer thin film such as TiOx (x ≦ 2), polyvinylbenz
Rutrimethylammonium chloride, oligo (poly)
Polyelectrolyte thin film system such as styrene sulfonate, poly
Anilines, polythiophenes, polypyrroles, etc.
A conductive organic film can be mentioned.

These conductive films are laminated on the polymer film by a well-known method like the above-mentioned high frequency circuit board. The conductive polymer can also be formed inside the film by an electrolytic polymerization method or a gas phase method.
Also, conductivity can be exhibited by impregnating a complex such as TTF-TCNQ (tetrathiofulvalene-tetracyanoquinodimethane).

[0032]

As described above, the conductive composite material of the present invention is excellent in transparency, exhibits strong resistance to acids and alkalis, is excellent in solvent resistance, has good workability, and has a large area. It has various features, such as high heat resistance, light weight and flexibility, thin film formation, excellent heat resistance, heat aging resistance, light stability, and electrical characteristics.

Therefore, when it is used for an electric circuit board for high frequency, (i) the dielectric constant is small, the propagation speed of the high frequency electric signal is high, and the dielectric loss is small, so that the attenuation of the electric signal is small, so that the high speed information transmission Can be realized, and highly sensitive reception of weak signals can also be realized. (Ii) Since it is rich in heat resistance, it is not deformed by being softened or melted in the heating / pressurizing step in manufacturing a circuit board. Therefore, the thickness of the circuit board can be accurately controlled. (Iii) It has excellent solder resistance. (Iv) The water absorption is small, and excellent electrical properties can be stably exhibited over a long period of time. (V) Excellent dimensional stability. It has the following features.

Therefore, it can be used for various circuit boards, flat antennas, housing-integrated boards, flexible boards and the like. The transparent conductive film can be used for the following purposes. That is, if necessary, a thin film of a photoconductor or derivative such as polyvinylcarbazole or cadmium sulfide is formed on the conductive film, and electrophotographic recording applications such as OHP, second original drawing, slide film and microfilm, EL
(Electroluminescence), liquid crystal, electrochromic, solid-state display applications such as electrophoretic display, thermoplastic recording, optical memory applications such as ferroelectric memory, terminal devices such as transparent tablets,
Meter windows, TV cathode-ray tubes, clean room windows and floors, semiconductor packaging materials, electromagnetic wave shielding applications, solar cell windows, photoelectric conversion elements such as optical amplifiers, heat ray reflection applications, surface heating elements applications such as automobile and aircraft defrosters. And so on.

[0035]

【Example】

[0036]

[Reference Examples 1 to 6] Methyltetracyclododecene

[0037]

Embedded image

And methyl norbornene

[0039]

Embedded image

And and ruthenium chloride (RuCl ₂ · 3H ₂
After reacting for about 3 hours at 100 ° C. in a glass ampoule in the presence of n-butanol solution of O), the product was washed with tetrahydrofuran and methanol and dried.

Next, the produced polymer is dissolved in tetrahydrofuran and hydrogen pressure is set to 5 in the presence of a palladium / silica catalyst.
After stirring at 0 kg / cm ² · G and 10 ° C for 30 minutes, the temperature was raised to 50 ° C and stirring was continued for 18 hours. The resulting precipitated product was dissolved in cyclohexane, filtered through a filter, reprecipitated with methanol and dried.

The hydrogenation rate of the obtained polymer was measured by NMR spectrum, Tg was measured by DSC, and light transmittance was measured by JIS K.
6717 and the water absorption were measured according to JIS K 6911. The results are shown in Table 1.

[0043]

[Table 1]

Next, various conductive composite materials were prepared using these polymers and evaluated as transparent conductive films or high-frequency circuit boards. An example is shown below.

[0045]

Example 1 Using the polymer obtained in Reference Example 2, a transparent film having a thickness of 0.1 mm and a width of 20 cm was formed by a T-die.

By a bipolar magnetron sputter (Nichiden Anelva), a high frequency power supply of 13.56 MHz was used, the substrate temperature was 50 ° C., and the target was In ₂ O ₃ / SnO ₂ = 90.
/ 10 (%) alloy target, Ar gas inflow,
Sputter pressure 1 × 10 ^-2 Torr, RF output 50W,
An ITO film was formed at a sputter speed of 250Å / min.
The film performance is based on Taylor Hobson
ITO thickness 3000Å was measured by Ltd.), a specific resistance 2 × 10 ^-3 Ω measured by the four probe method · cm, the light transmittance measured by a self-spectrophotometer UV365 (manufactured by Shimadzu) (400
nm to 750 nm) was 80%, and a good conductive film was obtained. There was no change even after irradiation with a carbon arc lamp for 35 hours.

[0047]

Example 2 Using the polymer obtained in Reference Example 6, a film having a thickness of 0.1 mm and a width of 20 cm was formed.

The target is CdO ₂ / SnO ₂ = 2/1
(Weight ratio), the reaction gas is O ₂ / Ar = 5/95 (%),
A TO film was formed at a sputter pressure of 2 × 10 ^-2 Torr, an RF output of 50 W, and a sputter rate of 200 Å / min. As a result, the conductive layer film 2500Å, the light transmittance 83%, the specific resistance 3
A transparent conductive film of × 10 ^-3 Ωcm was obtained. There was no change even after irradiation with a carbon arc lamp for 35 hours.

[0049]

Comparative Examples 1 to 3 Using the polymers shown in Reference Examples 1, 3 and 5, the polymer of Reference Example 1 was used in Example 1, the polymer of Reference Example 3 was used in Example 3 and Reference Example 5. A transparent conductive film was prepared from the polymer under the same conditions as in Example 2. Then, light was irradiated with a carbon arc lamp for 35 hours. Each transparent conductive film turned yellow and its specific resistance also decreased.

As can be seen from the above examples, the transparent conductive film of the present invention shows stable properties over a long period of time. However, as in the comparative example, those using the ring-opening polymer before hydrogenation are used. It can be seen that when it is exposed to light for a long period of time, discoloration occurs and it cannot withstand long-term use. Also, similar results are shown when heat is applied for a long period of time instead of light. Therefore, a transparent conductive film using a ring-opening polymer before hydrogenation is transparent for liquid crystal display devices, which is a specific application of the film. It cannot be practically used for electrodes or resistance heating elements.

[0051]

[Example 3] The polymer of Reference Example 2 was 30 mm in diameter made of thermoplastic resin, thickness was 1.5 mm and width was 20 cm by a T-die molding machine.
The sheet of was produced.

To this sheet (10 cm × 10 cm), electrolytic copper foil (35 μm thick) manufactured by Mitsui Mining & Smelting Co., Ltd. was stuck on both sides and fused at 260 ° C. by a press molding machine. The dielectric constant and the dielectric loss of the double-sided copper clad plate are 2.2 and 4.5 × 1, respectively.
The peel strength was 0 ^-4 and the peel strength was 1.0 kg / cm. Photoresist (Fuji Synthetic Chemical Research Laboratory No. 20
0) was coated, and a fine pattern was formed with an alkali developing solution and an etching treatment (ferric chloride saturated solution). As a result, a fine pattern of 100 μm or less could be formed.

[0053]

Example 4 Maleic anhydride was graft-copolymerized with the polymer of Reference Example 2 to obtain a modified product having a maleic anhydride content of 1.5 wt%. This polymer was added to the polymer of Reference Example 2 at 10 wt%
They were mixed, formed into a sheet, and fused with double-sided copper foil. The double-sided copper clad plate had a dielectric constant of 2.3 and a dielectric loss tangent of 6.5 × 10 ⁻⁴ . The peel strength was 1.6 kg / cm.

[0054]

Example 5 The polymer of Reference Example 4 was dissolved in cyclohexane, impregnated in a glass cloth for printed circuit boards, and dried. Six pieces of polymer-impregnated glass cloth are stacked and press-pressed at 260 ° C, and the thickness is 1.5 mm, Young's modulus is 8 × 10 ¹⁰ dyne
A high-rigidity body of / cm ² was obtained. Thereafter, a copper foil having a back surface coated with the modified product described in Example 5 to a thickness of 10 μm was attracted to both surfaces of the laminate. As a result, the dielectric constant of the double-sided copper clad board is 2.8,
The dielectric loss tangent was 5.8 × 10 ⁻⁴ , and the peel strength was 1.1 kg / cm.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Office reference number FI Technical display location H01P 3/08 H01P 3/08 H05K 1/03 610 7511-4E H05K 1/03 610H

Claims (4)

[Claims] 1. A polymer obtained by hydrogenation of a ring-opening polymer comprising tetracyclododecene or its derivative: 50 to 100 mol% and norbornene or its derivative: 0 to 50 mol%. A conductive composite material, wherein a conductive semiconductor film, an oxide semiconductor film, or a multilayer film is provided on the surface of the sheet or film. 2. The conductive composite material according to claim 1, wherein the conductive film has a light transmittance of 50% or more and a specific resistance of 100 Ωcm or less. 3. The conductive composite material according to claim 1, which is used as a transparent conductive film. 4. A polymer obtained by hydrogenation of a ring-opening polymer comprising tetracyclododecene or its derivative: 50 to 100 mol% and norbornene or its derivative: 0 to 50 mol%. 2. A high frequency circuit board comprising a conductive composite material in which a conductive organic film, a metal film, a semiconductor film, an oxide semiconductor film or a multilayer film is provided on the surface of the sheet or film.