JPH0582998B2 - - Google Patents

Description

[Detailed Description of the Invention] [Technical Field] The present invention relates to a transfer foil, which can be used to impart conductivity to the surface of materials that do not have conductivity on their own, such as plastics, ceramics, and glass, or to provide printed electrical circuits. This invention relates to a conductive transfer foil that is highly conductive and has good corrosion resistance. [Prior Art] Conventionally, as a transfer foil whose surface is conductive after transfer, as in the invention described in Japanese Unexamined Patent Application Publication No. 47-46106, conventionally, a release layer is attached to the transferred object after transfer. There was a transfer foil that remained attached to the substrate without adhering to the surface of the transfer material, but this foil did not have a film to protect the surface of the object, especially the metal layer, after transfer. Although it has electrical conductivity, it has extremely low physical and chemical stability such as surface strength, acid resistance, and alkali resistance, and is therefore of little practical use. This defect has been improved by a case where metal is exposed on the surface of the transferred object due to the presence of a metal vapor deposited layer underneath, despite the presence of a release layer on the surface of the transferred object after transfer. Transfer foils have also been proposed whose peeled portions have approximately the same conductivity. However, since the mold release layer uses acrylic resin, cellulose acetate, cellulose butyrate, or other resins with mold release properties, stable conductivity cannot be obtained in practice, making it impossible to put it to practical use. It was hot. Furthermore, the applicant has previously filed an application (Japanese Patent Application No. 50179/1983) for an invention that improves this drawback. It is a conductive transfer foil characterized by using a combination of a coating resin layer containing conductive fine particles and a metal vapor deposition layer as a transfer layer. This material has improved chemical and physical stability such as electrical conductivity, surface strength, acid resistance, alkali resistance, etc., as compared to the conductive transfer foil based on the prior art. However, when copper or silver, which has relatively good conductivity, is used as the vapor-deposited metal, the electric resistance value increases due to corrosion of the vapor-deposited metal when the transfer material is stored at high temperature and high humidity. In addition, when nickel, chromium, or other alloys with relatively good corrosion resistance are used as vapor-deposited metals, there is little change in electrical resistance even after the transfer is stored at high temperature and high humidity, but the conductivity is inferior to copper or silver. Therefore, the initial resistance value is relatively high and it cannot be used for circuit printing. As described above, it has been difficult to satisfy both good electrical conductivity and corrosion resistance stability with conventional techniques. Furthermore, if gold is used for the vapor-deposited metal layer, it is possible to satisfy both electrical conductivity and corrosion resistance, but the cost is naturally high and it cannot be put to practical use. Purpose of the Invention In view of the above conventional problems, the present invention has extremely good conductivity, stable surface strength with corrosion resistance, and extremely high physical and chemical stability such as acid resistance and alkali resistance. An object of the present invention is to provide a conductive transfer foil. [Structure of the Invention] That is, the present invention provides that at least a coating resin layer containing conductive fine particles, a highly conductive metal vapor deposition layer, and a corrosion-resistant vapor deposition layer are sequentially formed on a base film directly or via a release agent layer. The present invention relates to a conductive transfer foil characterized by: That is, in the conductive transfer foil of the present invention, the drawback that when a highly conductive metal vapor deposited layer is used, the metal vapor deposited layer corrodes under high temperature and high humidity conditions and the electrical resistance value increases, can be overcome by using a conductive metal in the vapor deposited layer. A stack of at least two layers consisting of a vapor deposited layer and a corrosion resistant vapor deposited layer is used. More specifically, we have achieved extremely good conductivity by using a lamination of a highly conductive metal vapor deposited layer made of a highly conductive metal and a corrosion resistant vapor deposited layer made of a highly corrosion resistant metal, alloy, or metal oxide. This is a conductive transfer foil that has extremely high physical and chemical stability such as stable surface strength, acid resistance, and alkali resistance. That is, in the present invention, a coating resin layer 3 containing conductive fine particles, a highly conductive metal vapor deposition layer 4, and a corrosion-resistant vapor deposition layer 5 are sequentially formed on a base film 1 directly or via a release agent layer 2, and as necessary. Accordingly, it has become possible to provide a conductive transfer foil characterized in that an adhesive layer 6 is further provided thereon. Furthermore, in the above configuration, between the coating resin layer 3 containing conductive fine particles and the highly conductive metal vapor deposited layer 4,
It is even more effective to provide a relatively thin vapor deposition layer 7 made of a metal or alloy that has conductivity that does not impair the conductivity of the entire transfer layer and has good corrosion resistance. As the base film 1 in the conductive transfer foil of the present invention, any material can be used as long as it has sufficient self-retention properties, such as polyester, polyamide, polyamideimide, polyethylene, polypropylene, cellulose acetate, polycarbonate, and polychloride. Resins such as vinyl and fluorine resins, film or sheet materials such as cellophane paper and glassine paper, film or sheet materials of stainless steel or other metals, release paper or release films, and the like are used as appropriate. In particular, it is preferable to use a film-like material of the above-mentioned resins having a thickness of about 9 to 50 μm as the base film 1, since it is possible to continuously mass-produce conductive transfer foil without wrinkles or cracks. If the base film 1 does not have good releasability from the coating resin layer 3 containing conductive particles, a release agent layer 2 may be formed by applying paraffin wax, silicone, fluororesin, surfactant, etc. You can leave it as is. As the coating resin layer 3 containing conductive fine particles of the conductive transfer foil of the present invention, any material can be used as long as it has sufficient heat resistance, such as polyethylene, acrylic resin, vinyl chloride-vinyl acetate copolymer, Nitrocellulose, epoxy resin, polyurethane resin, polysulfonic acid ether resin, polycarbonate resin, polyarylate resin, polystyrene resin, polyethylene terephthalate resin, polyimide resin, rubber, etc. are used as appropriate. In particular, it is preferable to use a resin having a thickness of about 1 to 10 μm as the conductive fine particle-containing coating resin layer 3 because it allows continuous mass production of conductive transfer foil without wrinkles or cracks. If it is thinner than 1 μm, it is difficult to obtain conductive transfer foil that has sufficiently stable conductivity and has high physical and chemical stability such as surface strength, acid resistance, and alkali resistance. This is not preferable because it makes it difficult to transfer the electric circuit pattern. The conductive fine particles dispersed in the coating resin layer 3 containing conductive fine particles in the conductive transfer foil of the present invention include, for example, carbon black, conductive tin oxide fine particles, gold fine particles, etc., which have physical properties such as acid resistance and alkali resistance. Conductive fine particles with excellent physical, chemical, and stability can be used. In addition, commercially available conductive paints and conductive adhesives can also be used to form the coating resin layer containing conductive fine particles. In the conductive transfer foil of the present invention, the content of the conductive fine particles dispersed in the conductive fine particle-containing coating resin layer 3 is usually appropriately determined depending on how conductive the surface of the transferred object is ultimately made. Depending on the selection, 20 to 100% of the coating resin
(wt%, the same applies hereinafter). Content of dispersed conductive fine particles in coating resin
If it is less than 20%, not only is it not possible to impart sufficient conductivity to the coating resin layer, but also the surface of the transferred object transferred using the conductive transfer foil of the present invention cannot be made to have stable conductivity. I don't like it. On the other hand, if it exceeds 100%, the film properties of the coating resin layer containing conductive fine particles become brittle, and even though it has conductivity, surface strength such as friction resistance and crack resistance deteriorates, which is not preferable. Good conductive metal vapor deposition layer 4 of the conductive transfer foil of the present invention
is formed by depositing a metal such as aluminum, copper, silver, gold, or an alloy thereof on the coating resin layer containing conductive fine particles by a conventional method, and copper is most preferable from the viewpoint of conductivity and cost.
The thickness is usually appropriately selected and determined depending on how conductive the surface of the object to be transferred is ultimately made and the type of metal, but it is usually necessary to have a thickness of about 30 nm or more. If the thickness of the metal vapor deposition layer is less than 30 nm, not only will the metal vapor deposition layer not have stable and sufficient conductivity, but also the surface of the transferred object transferred using the conductive transfer foil of the present invention will not have stable electrical conductivity. This is not desirable as it cannot be As the corrosion-resistant vapor deposition layer 5 of the conductive transfer foil of the present invention, for example, aluminum oxide, titanium nitride, stainless steel, nickel-chromium alloy, chromium, etc. It is formed by vapor deposition of metals, alloys, or metal oxides such as. The thickness is normally selected and determined depending on the degree of corrosion resistance ultimately required and the type of deposited material, but usually
The purpose of preventing corrosion of a highly conductive deposited layer can be achieved at a thickness of 5 nm or more, more preferably 20 nm or more. If the thickness of this vapor-deposited layer is less than 5 nm, stable corrosion resistance cannot be obtained, which is not preferable. Examples of the adhesive layer 6 of the conductive transfer foil of the present invention include polyester resin, polyamide resin, polyethylene, acrylic resin, vinyl chloride-vinyl acetate copolymer, nitrocellulose, epoxy resin,
Polyurethane resins, polysulfonic acid ether resins, polycarbonate resins, polyarylate resins, polystyrene resins, polyethylene terephthalate resins, polyimide resins, rubbers, and the like may be used alone or in combination. The thickness of the adhesive layer 6 is appropriately selected depending on the surface condition of the object to be transferred, etc., but it is usually selected from a range of about 1 to 10 μm, and is suitable for cases where the surface of the object to be transferred is relatively smooth. It is sufficient to provide either the surface of the transferred object or the conductive transfer foil, but when transferring to an object with an uneven surface such as glass cloth, the conductive transfer foil and the conductive transfer foil may be used. An adhesive layer may also be provided on both sides. A relatively thick film of a metal or alloy having a certain degree of conductivity and good corrosion resistance, which is optionally provided between the conductive fine particle-containing coating resin layer 3 and the highly conductive metal vapor deposition layer 4 of the conductive transfer foil of the present invention. A thin corrosion-resistant conductive evaporation layer 7 is formed on the coating resin layer containing conductive particles by a conventional method such as nickel, nickel-chromium alloy, stainless steel.
It is formed by vapor deposition of metals or alloys such as metals. This layer is provided to prevent corrosion from acting on the surface of the transfer obtained using the conductive transfer foil of the present invention, that is, the highly conductive metal vapor deposited layer through the conductive fine particle coating resin layer, and its thickness is determined by the conductivity of the entire transfer layer. In order to satisfy the corrosion resistance function without impairing properties, it is usually desirable to have a thickness of about 5 to 50 nm. If the thickness of this vapor-deposited layer is less than 5 nm, stable corrosion resistance cannot be obtained, and if the thickness exceeds 50 nm, the conductivity of the entire transfer layer decreases, which is not preferable. Next, the present invention will be explained with reference to Examples. [Example] Example 1 100 parts of polyurethane resin (parts by weight, the same applies hereinafter) and 40 parts of carbon black were added to methyl isobutyl ketone on a 30 μm thick polypropylene film.
45 parts of ethyl acetate and 60 parts of toluene is applied and dried to form a coating resin layer containing conductive fine particles with a thickness of 3 μm, and on top of that a coating resin layer containing conductive fine particles is applied. was deposited by sputtering to a thickness of 20 nm, and then copper was deposited on top of it by vacuum evaporation.
Chromium was vapor-deposited to a thickness of 200 nm, and chromium was vapor-deposited to a thickness of 40 nm by electron beam evaporation, and then 12 parts of vinyl acetate resin and 8 parts of coumaron resin were added from 24 parts of toluene and 56 parts of ethyl acetate. A coating solution prepared by dissolving in a mixed solvent was applied and dried to form an adhesive layer with a thickness of 2 μm to obtain a conductive transfer foil of the present invention. Example 2 100 parts of polyurethane resin (parts by weight, the same applies hereinafter) and 40 parts of carbon black were placed on a 30 μm thick polypropylene film with methyl isobutyl ketone.
45 parts of ethyl acetate and 60 parts of toluene is applied and dried to form a coating resin layer containing conductive fine particles with a thickness of 3 μm, and copper is vacuum evaporated on top of the coating solution. chromium was deposited to a thickness of 200 nm using an electron beam evaporation method, and then chromium was deposited to a thickness of 40 nm using an electron beam evaporation method.
Furthermore, a coating solution made by dissolving 12 parts of vinyl acetate resin and 8 parts of coumaron resin in a mixed solvent consisting of 24 parts of toluene and 56 parts of ethyl acetate was applied and dried to form an adhesive layer with a thickness of 2 μm. A conductive transfer foil of the present invention was obtained. Comparative Example 1 In the same manner as in Example 1, 100 parts of polyurethane resin (parts by weight, hereinafter the same) and 40 parts of carbon black were placed on a 30 μm thick polypropylene film with 45 parts of methyl isobutyl ketone, 45 parts of ethyl acetate, and 60 parts of toluene. A coating solution made by dissolving in a mixed solvent consisting of
A coating resin layer containing conductive fine particles of m is formed, on which copper is deposited to a thickness of 200 nm by vacuum evaporation, and on top of that, 12 parts of vinyl acetate resin and 8 parts of coumaron resin are mixed with 24 parts of toluene and 56 parts of ethyl acetate. A coating solution prepared by dissolving in a mixed solvent consisting of 50% and 100% was applied and dried to form an adhesive layer with a thickness of 2 μm to obtain a conductive transfer foil. Comparative Example 2 In the same manner as in Example 1, 100 parts of polyurethane resin (parts by weight, hereinafter the same) and 40 parts of carbon black were placed on a 30 μm thick polypropylene film with 45 parts of methyl isobutyl ketone, 45 parts of ethyl acetate, and 60 parts of toluene. A coating solution made by dissolving in a mixed solvent consisting of
A coating resin layer containing conductive fine particles of m is formed, and nickel is deposited on it to a thickness of 200 nm using a vacuum evaporation method. On top of that, 12 parts of vinyl acetate resin and 8 parts of coumaron resin are mixed with 24 parts of toluene and ethyl acetate. 56
A coating solution prepared by dissolving in a mixed solvent consisting of 50% and 100% was applied and dried to form an adhesive layer with a thickness of 2 μm to obtain a conductive transfer foil. [Effect of the invention] The transfer film on the acrylic resin plate obtained by transferring the conductive transfer foils obtained in Examples 1 and 2, Comparative Example 1 and Comparative Example 2 onto the acrylic resin plate Initial surface resistance value and 40℃, 90%RH or
Table 1 shows the measurement results of surface resistance values after being left in an atmosphere of 60°C and 98% RH for 240 hours. 【table】

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the structure of the conductive transfer foil of the present invention. Reference numbers in the drawings: 1...Base film, 2...Release agent layer, 3...Coating resin layer containing conductive fine particles, 4...Good conductive metal vapor deposition layer, 5...Corrosion resistant vapor deposition layer, 6... Adhesive layer, 7...Corrosion-resistant conductive vapor deposited layer.

Claims (1)

[Claims of Claims] 1. At least a coating resin layer containing conductive fine particles, a highly conductive metal vapor deposition layer, and a corrosion-resistant vapor deposition layer are sequentially formed on a base film directly or via a release agent layer. conductive transfer foil. 2. The conductive transfer foil according to claim 1, comprising an adhesive layer provided on the corrosion-resistant vapor deposited layer. 3. The conductive transfer foil according to claim 1 or 2, wherein a corrosion-resistant conductive vapor deposited layer is provided between the coating resin layer containing conductive fine particles and the highly conductive metal vapor deposited layer.