JPS629416B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a laminate having transparent conductivity and/or selective light transmittance, and more particularly, the present invention relates to a laminate having transparent conductivity and/or selective light transmittance, and more particularly, it consists of a transparent molded substrate having a metal thin film layer on at least one side coated with a transparent high refractive index dielectric layer on both sides. Regarding a laminate. Transparent conductive films are widely used in the electronics and electrical fields for applications that utilize their conductivity, such as electrodes for liquid crystal displays, electrodes for electroluminescent materials, electrodes for photoconductive photoreceptors, antistatic layers, and surface heating elements. It's being used. In addition, the selective light transmitting film is transparent to light in the visible light range and has a reflective ability to light with long wavelengths longer than near-infrared light, so it is useful as a transparent heat insulating film. Therefore, it can be used in solar energy collectors, water heaters, solar power generation greenhouses, building windows, etc. In particular, the use of solar energy from windows, which occupy a large proportion of the wall surface of modern buildings, and the function of transparent insulating windows that prevent energy dissipation are expected to become increasingly important in the future. In this way, transparent conductive films and permselective films are extremely important from the viewpoint of electronics and solar energy utilization, and the industry is hoping that homogeneous, high-performance films can be supplied industrially at low cost and in large quantities. It was coveted. Conventionally known transparent conductive films include metal thin films such as gold, copper, silver, and palladium, compound semiconductor films such as indium oxide, tin oxide, and copper iodide, and gold, silver, copper, and palladium films. It is known that a conductive metal film such as the above is made selectively transparent over a certain wavelength range. However, due to film performance, substrate limitations caused by the manufacturing process, resources, and cost constraints, the above methods cannot produce selectively transparent films that have high transparency for visible light and high reflectivity for infrared rays. It has not yet been provided on an economic and industrial scale. For example, the above-mentioned typical structure is a laminate in which a metal thin film is sandwiched between transparent high refractive index dielectric thin films, such as Bi ₂ O ₃ /Au/Bi ₂ O ₃ formed by vacuum evaporation, reactive evaporation, or sputtering. ZnS／Ag／ZnS
Alternatively, a laminate having a sandwich structure such as TiO ₂ /Ag/TiO ₂ has been proposed. Among these, those using silver as a metal layer have excellent transparency in the visible light region and reflective properties for infrared light due to the optical properties of silver itself, and also have favorable properties in terms of conductivity. It is particularly excellent as a material because of its properties. However, the method of forming a transparent high refractive index dielectric thin film by means such as vacuum evaporation, reactive evaporation, or sputtering as described above is (a) slow in film formation. (b) It is difficult to control the composition and film thickness. (c) Forming a film over a large area requires large equipment and requires a huge investment in equipment. Due to these disadvantages, it is difficult to provide inexpensive products as described above. As a means to solve such economical disadvantages, the present inventors have discovered a means to form a high refractive index dielectric thin film layer at low cost by a chemical coating method, and have already filed an application for the method. However, the laminated film consisting of a silver thin film layer covered with a transparent refractive index dielectric thin film layer formed by such a method is susceptible to deterioration in performance due to environmental conditions such as heat, light, gas, etc., and cannot be stably maintained for a long time. It is often difficult to maintain its performance over a period of time. This deterioration is thought to be mainly due to the diffusion of silver toward the surface layer in the transparent high refractive index dielectric thin film layer. As a result of intensive research to obtain a laminate having excellent transparent conductivity and/or selective light transmittance without such drawbacks, the present inventors found that a single thin film layer in which silver and gold coexist, containing a specific amount of gold. The present invention was achieved based on the discovery that the above-mentioned drawbacks can be greatly improved by providing a metal layer contact-treated with a sulfur compound at least at the interface of the metal layer. That is, the present invention has the following features: 1. On at least one side of a transparent molded substrate (A), a transparent high refractive index dielectric thin film layer (B), a metal thin film layer (C) consisting of a single thin film layer in which silver and gold coexist, and In a laminate in which transparent high refractive index dielectric thin film layers (D) are sequentially laminated, at least the interface of the metal thin film layer (C) in contact with the transparent high refractive index dielectric thin film layer (B) and/or (D) is A laminate characterized by containing silver sulfide. 2. The transparent high refractive index dielectric thin film layer (B) and/or (D)
The laminate according to item 1 above, wherein is a titanium oxide thin film layer formed by hydrolysis of an alkyl titanate. 3 The metal thin film layer (C) contains 3% by weight to 30% by weight of gold.
2. The laminate according to item 1, wherein the laminate is a single thin film layer in which gold and silver coexisting. 4 At least one side of the transparent molded substrate (A) is coated with a transparent high refractive index dielectric thin film layer (B) of 3% by weight of gold.
A laminate in which a metal thin film layer (C) consisting of a single thin film layer in which gold and silver containing up to 30% by weight coexist and a transparent high refractive index dielectric thin film layer (D) are successively laminated is a transparent high refractive index dielectric thin film. In the method of producing the layer (B) and/or (D) by hydrolyzing an alkyl titanate, the metal thin film layer (C) is formed of a thiourea or a thiourea having a sulfur atom active against silver. It is characterized by contact treatment with at least one sulfur compound selected from the group consisting of hydrocarbon group derivatives having 20 or less carbon atoms, mercaptan compounds, thiazole compounds, sodium sulfide, and sodium thiosulfate. Method for manufacturing a laminate. 5. The method for producing a laminate according to item 4 above, wherein the contact treatment is achieved by a sulfur compound mixed into the alkyl titanate. 6. The manufacturing method according to item 3 above, wherein the contact treatment is achieved by contacting the metal thin film layer (C) with a sulfur compound in gaseous, liquid or solution form. 7. Item 3 above, wherein the contact treatment is achieved by contact-treating the transparent high refractive index dielectric thin film layer (B) with a gaseous, liquid or solution sulfur compound before forming the metal thin film layer (C). This is the manufacturing method described. Therefore, the subject matter of the present invention is a method for improving a transparent conductive film and/or a laminate having selective light transmittance by treatment with a sulfur compound, and it is an object of the present invention to provide the laminate and a method for manufacturing the same. . Hereinafter, each matter of the present invention will be explained in detail. The transparent molded substrate (A) used in the present invention may be an organic type, an inorganic type, or a composite molded product thereof. Examples of organic molded products include molded products of polyethylene terephthalate resin, polyethylene naphthalate resin, polybutylene terephthalate resin, polycarbonate resin, acrylic resin, polyamide resin, and other resins. On the other hand, examples of inorganic molded products include molded products of glass such as soda glass and borosilicate glass, and metal oxides such as alumina, magnesia, zirconia, and silica. These molded products are molded into any shape such as a plate, sheet, film, or rod, and depending on the purpose, colored or uncolored transparent ones are selected. However, from the viewpoint of processability, sheet-like, film-like, and plate-like materials are preferable, and among them, film-like materials are particularly preferable from the viewpoint of productivity. Further, a biaxially oriented polyethylene terephthalate film is preferred from the viewpoints of transparency, film strength, adhesion to the laminate, and the like. The transparent high refractive index dielectric thin film layer (B) or (D) constituting the laminate of the present invention is not particularly limited as long as it has the effect of preventing reflection in the metal layer, but has a refractive index of 1.7 or more, preferably 1.8 or more, and visible light transmittance of 80%
Above, preferably 90% or more is effective. The film thickness is 50 to 1000 Å, preferably 100 to 100 Å.
It is 500Å. Examples of materials that meet these conditions include thin film layers of titanium oxide, zirconium oxide, bismuth oxide, zinc oxide, tin oxide, indium oxide, and the like. These thin film layers can be provided by methods such as sputtering, vacuum deposition, ion plating, and wet coating. In particular, the present invention exhibits its effects when a titanium oxide thin film with excellent optical properties is used as the transparent high refractive index dielectric thin film (B) or (D). This is the case when a titanium oxide thin film layer formed from titanate is used. A titanium oxide thin film layer formed from an alkyl titanate has good adhesion to an organic substrate and is preferable from this point of view as well. The metal thin film layer (C) used in the laminate of the present invention is a single metal thin film layer in which gold and silver coexist, but this means a metal thin film in which silver atoms and gold atoms substantially coexist. It may be completely homogeneous or it may be non-uniform to some extent, but at least it exists as a single layer. Furthermore, other components such as copper, aluminum, nickel, palladium, platinum, indium, tin, cadmium, germanium, zinc, etc. may be present to the extent that they do not impair the intended effects of the present invention. The single thin film layer in which silver and gold coexist in the laminate, which is the object of the present invention, can be produced by various methods. For example, a method such as vacuum deposition or sputtering using an alloy of silver and gold, or a multi-component vapor deposition method or multi-component sputtering method in which silver and gold are vacuum deposited or sputtered separately can be used. The metal thin film layer created by either method can achieve the object of the present invention when gold coexists with silver. Such a metal thin film layer in which gold and silver coexist has higher environmental stability than a metal thin film layer composed only of silver, and can be expected to be more effective in the present invention. In addition, since gold is chemically more stable than other metals, it is not only easy to set the manufacturing conditions when forming the transparent high refractive index thin film layer (B) on the metal layer in the manufacturing process, but also the lamination process. The chemical stability of the body also improves. More surprisingly, the presence of adequate gold in the silver thin film layer also improves the chemical properties of the laminate constructed in combination with the transparent high refractive index thin film layer. Although the mechanism of gold's action on this effect is not clear, the presence of gold facilitates nucleation during the initial stage of deposition, facilitates the formation of thinner continuous thin film layers, and furthermore helps create dense films with low scattering loss. This is thought to be because it can be formed. Although such an effect can be obtained with copper, it is even more pronounced with gold. Effects can be expected even if the amount of gold coexisting with silver is very small. Further, since the color tone of the laminate changes somewhat depending on the amount of gold coexisting with silver, the amount of gold to be added can be selected depending on the color tone suitable for the purpose. That is, as the gold content increases, the transmitted color changes from bluish to goldenish, and when compared at the same film thickness, the visible light transmittance decreases as the gold content increases. When compared at the same film thickness, the infrared light reflectance also decreases as the gold content increases. Because of the influence that the gold content has on various optical properties, the amount of gold contained in the metal thin film layer (C) ranges from 3% by weight to 30% by weight.
Weight percent is preferred. The thickness of the metal thin film is not particularly limited as long as it has the required characteristics as a transparent conductive film or a selective light transmission film, but in order to have infrared light reflecting ability or conductivity, it must have at least a certain range of thickness. It is necessary to have continuity. The film thickness is preferably about 30 Å or more as it gives a continuous structure rather than an island structure, and is preferably 500 Å or less in terms of transparency to solar energy. The thinner the metal thin film layer is, the wider the light transmission area becomes, so to increase transparency it is best to have a film thickness of 200 Å or less, and to have sufficient conductivity or infrared light reflection ability, it should be 50 Å or more. A film thickness of . As mentioned above, the method for forming the metal thin film layer (C) includes, for example, the vacuum evaporation method, the cathode sputtering method,
Plasma spraying method, vapor phase plating method, chemical plating method,
Both electroplating and a combination of these methods are possible, but in the case of a laminate using a molded substrate, if the surface of the substrate such as a sheet or film is smooth, the uniformity of the formed thin film and the manufacturing process may be affected. In terms of ease and film formation speed, vacuum evaporation is particularly suitable. In order to keep the composition of silver and gold in the film as uniform as possible during film formation, an alloy or multi-component sputtering method is suitable, and in the vacuum evaporation method, a multi-component evaporation method or an alloy sample and electron beam heating method is suitable. , a high-frequency induction heating method, a resistance heating method, a flash vapor deposition method, and the like are preferred. Further, the sulfur compound used in the present invention is a compound having a sulfur atom that is active toward silver, and includes thiourea and its derivatives, mercaptans,
Examples include organic sulfur compounds such as thiazole compounds and inorganic active sulfur atom compounds. As a thiourea derivative, the hydrogen atom of the amino group is a hydrocarbon group,
Examples include those substituted with a hydrocarbon group having 20 or less carbon atoms, such as allylthiourea, N-benzylthiourea, N-methylthiourea, N.N'-dimethylthiourea, N-ethylthiourea, N.
Examples include N'-diethylthiourea, N-naphthylthiourea, N-phenylthiourea, N.N'-diphenylthiourea and N-ethylidenethiourea. In addition, mercaptans include 2-mercaptoethanol, and thiazole compounds include 2-mercaptoethanol.
Examples include -mercaptothiazoline, sodium mercaptobenzothiazole, bezothiazole, etc. Examples of inorganic active sulfur atom-containing compounds include sodium sulfide and sodium thiosulfate. Among these, thiourea and its derivatives are preferred; as thiourea derivatives, those in which the hydrogen atom of the amino group is substituted with a hydrocarbon group having 6 or less carbon atoms are preferred; Sodium and sodium thiosulfate are preferred. These compounds may be used alone or as a mixture of two or more. Various methods can be used to contain silver sulfide at least at the interface of the metal thin film layer (C) using these compounds. A method of bringing a sulfur compound into contact with the metal thin film layer (C) to sulfidize at least the interface, or a method of bringing a sulfur compound into contact with the metal thin film layer (C) through a transparent high refractive index dielectric to sulfidize at least the interface. The method can be preferably applied. The method of bringing a sulfur compound into direct contact with the metal thin film layer (C) is usually to provide a transparent high refractive index dielectric layer (B) on the transparent molded substrate (A), and then add the metal thin film layer (C).
The laminate obtained by providing the above may be brought into contact with a sulfur compound in a gaseous, liquid or solution form. In the case of gaseous sulfur compounds, they may of course be diluted with other gases. This can usually be achieved by contacting the gaseous sulfur compound with 0.01-0.2% by volume of gas at a temperature of 10-100°C for a few seconds to several minutes. Sulfur compounds suitable for such contact treatment include hydrogen sulfide. Any conventionally known means may be used to bring the material into contact with the sulfur compound in liquid or solution form, and a dipping method, a spraying method, etc. can generally be applied. In this case as well, the objective can be achieved by contacting with a (solution) solution of 0.01 mol % or more at a temperature of 10 to 100°C for several seconds to several minutes. Sulfur compounds suitable for such contact treatment include thiourea and its derivatives, sodium sulfide, and sodium thiosulfate. Furthermore, as a means for making contact via a transparent high refractive index dielectric, the above-mentioned treatment is applied to the transparent high refractive index dielectric thin film layer (B) to contain a sulfur compound at least on its surface or surface layer, and then , when the metal thin film layer (C) provided thereon is brought into contact or the transparent high refractive index dielectric thin film layers (B) and (D) are formed by a wet coating method, a sulfur compound is added to the stock solution. A method of forming a transparent high refractive index dielectric thin film layer (B) and/or (D) containing sulfur atoms by mixing, and thus sulfidizing at least the interface of the metal thin film layer (C) in contact with the transparent high refractive index dielectric thin film layer (B) and/or (D). can be mentioned. The latter will be explained in more detail as follows. The titanium oxide thin film layer constituting the laminate can be provided, for example, by using an organic solvent solution of a solute containing an alkyl titanate as a main component.
Examples of the alkyl titanate include tetrabutyl titanate, tetraethyl titanate, tetrapropyl titanate, diisopropoxy titanium, and bisacetylacetonate, with tetrabutyl titanate and tetrapropyl titanate being particularly preferred. These alkyl titanates may be used as they are, or precondensed products such as dimers, tetramers, and decamers can also be preferably used. These alkyl titanates may also be stabilized with a compound such as acetylacetone before use. To create a titanium oxide thin film layer from alkyl titanate, either apply an organic solvent solution of alkyl titanate to the surface of the substrate, or use a general solution coating method such as dipping, spraying, spinner coating, or machine coating. be able to. In order to create a sulfur-containing titanium oxide thin film layer, organic sulfur compounds such as thiourea or its derivatives, mercaptans and thiazole compounds, or sodium sulfide, sodium thiosulfate, etc. are added to the organic solvent solution of the alkyl titanate. It is made by adding an inorganic sulfur compound at an appropriate concentration (1 to 15% sulfur atoms to the number of Ti atoms) and coating it on the surface of the substrate. By heating after coating in this manner, the alkyl titanate is hydrolyzed to form a sulfur-containing titanium oxide thin film layer. According to this method, by adjusting the film formation conditions of the thin film layer, the remaining amount of alkyl groups in the titanium oxide layer can be adjusted to 0.5 to 10% by weight, and thus Adhesion can be improved. Furthermore, the state of sulfur present can be adjusted, and as a result, silver sulfide can be contained at least at the interface of the metal thin film layer to a degree that is preferable for the durability of the laminate. Hereinafter, a more specific explanation of the present invention will be shown in Examples. In the examples, the light transmittance is a value at a wavelength of 500 nm unless otherwise specified. The infrared reflectance was measured by attaching a reflectance measurement device to a Hitachi EPI-type infrared spectrometer and measuring the reflectance of a slide glass with sufficiently thick (approx. 3000 Å) vacuum-deposited silver.
Measurements were taken at 100% and 10μ unless otherwise specified. Examples 1 to 5 Five biaxially stretched polyethylene terephthalate films with a light transmittance of 86% and a thickness of 50μ, each having a titanium oxide layer with a thickness of 300Å as the first layer and a gold layer with a thickness of 170Å with different gold contents as the second layer. and a metal layer in which silver coexists (gold content is 5% by weight, 10% by weight, and 15% by weight, respectively)
(wt%, 20 wt%, 30 wt%) and a titanium oxide layer with a thickness of 300 Å as the third layer were sequentially laminated to form a laminate having transparent conductivity and selective light transmittance on the film. . The first and third titanium oxide thin film layers each contain 1 part of tetrabutyl titanate, 23 parts of isopropyl alcohol, 1 part of acetylacetone, and 2 parts of water.
0.01% by weight of thiourea was added to a solution consisting of
It was heated and set. The metal layer was formed to a predetermined thickness by magnetron sputtering using a metal plate made of silver and gold containing gold corresponding to each gold content as a target. The thus obtained laminate was subjected to a heat resistance test using a hot air dryer at 90°C, changes in heat resistance were tracked by changes in infrared reflectance, and the infrared reflectance was measured after 1500 hours and compared to the initial value. compared. Similarly, this laminate was tested for light resistance using a carbon arc weather meter. In this case too
The infrared reflectance after 1000 hours was measured and compared with the initial value. The results are shown in Table-1.

[Table] Comparative Examples 1 to 3 Titanium oxide thin film layer made of tetrabutyl titanate 1
Example 1, except that a solution consisting of 23 parts of isopropyl alcohol, 1 part of acetylacetone, and 2 parts of water was applied with a bar coater and heated to 120°C.
A laminate was constructed in the same manner as in 2 and 3. The thus obtained laminate was evaluated using the same method as in Examples 1, 2, and 3. The results are shown in Table 2.

[Table] In all cases, the degree of deterioration was greater than in Examples 1, 2, and 3, and the environmental stability was poor. Examples 6-8 0.01 sodium sulfide, sodium thiosulfate or mercaptobenzothiazole in place of thiourea
Example 1 (metal layer) except that the first and third titanium oxide layers were formed using a coating solution (1 part of tetrabutyl titanate, 23 parts of isopropyl alcohol, 1 part of acetylacetone, 2 parts of water) added by weight%. A laminate was formed in exactly the same manner as (gold content: 5% by weight). The durability of the thus obtained laminate was evaluated in the same manner as in Example 1, and the results are shown in Table 3.

[Table] Example 9 After laminating the first and second layers on a biaxially stretched polyethylene terephthalate film in the same manner as in Comparative Example 1, the metal layer containing gold and silver was heated with air containing 0.04 vol% H ₂ S. , after contact treatment at room temperature for 60 seconds, the third
The titanium oxide layer of the layer was formed in exactly the same manner as in Comparative Example 1. However, after contacting with H ₂ S gas and confirming the formation of silver sulfide by fluorescent X-ray analysis, the third layer was formed. The durability of the thus obtained laminate was evaluated in the same manner as in Example 1, and the results are shown in Table 4.

[Table] Comparative Example 4 The thickness of the metal thin film layer was increased by vacuum evaporating silver.
The first and third titanium oxide layers were provided on a polyethylene terephthalate film in the same manner as in Example 1 except that they were provided at a thickness of 180 Å. The thus obtained laminate was evaluated in the same manner as in Example 1, and the results are shown in Table 5.

【table】

Claims (1)

[Claims] 1. At least one side of a transparent molded substrate (A) is provided with a transparent high refractive index dielectric thin film layer (B) and a metal thin film layer (C) consisting of a single thin film layer in which silver and gold coexist. ) and a transparent high refractive index dielectric thin film layer (D) are sequentially laminated, in which a small portion of the metal thin film layer (C) is in contact with the transparent high refractive index dielectric thin film layer (B) and/or (D). A laminate characterized in that both interfaces contain silver sulfide. 2. The transparent high refractive index dielectric thin film layer (B) and/or (D)
The laminate according to claim 1, wherein is a titanium oxide thin film layer formed by hydrolysis of an alkyl titanate. 3 The metal thin film layer (C) contains 3% by weight to 30% by weight of gold.
The laminate according to claim 1, wherein the laminate is a single thin film layer in which gold and silver coexisting. 4 At least on one side of a transparent molded substrate (A), a transparent high refractive index dielectric thin film layer (B), a metal thin film consisting of a single thin film layer in which gold and silver containing 3% to 30% by weight of gold coexist. A laminate in which the layer (C) and the transparent high refractive index dielectric thin film layer (D) are sequentially laminated is prepared by forming the transparent high refractive index dielectric thin film layer (B) and/or (D) by hydrolyzing alkyl titanate. In the manufacturing method, the metal thin film layer (C) is formed by forming a thiourea having a sulfur atom that is active toward silver, or a thiourea having 20 carbon atoms.
Production of a laminate characterized by contact treatment with at least one sulfur compound selected from the group consisting of hydrocarbon group derivatives, mercaptan compounds, thiazole compounds, sodium sulfide, and sodium thiosulfate. Method. 5. The method for producing a laminate according to claim 4, wherein the contact treatment is achieved by a sulfur compound mixed into the alkyl titanate. 6. The method for producing a laminate according to claim 4, wherein the contact treatment is achieved by contacting the metal thin film layer (C) with a sulfur compound in the form of a gas, liquid or solution. 7. Claim No. 7, wherein the contact treatment is achieved by contact treatment of the transparent high refractive index dielectric layer (B) with a gaseous, liquid or solution sulfur compound before forming the metal thin film layer (C). 4. A method for producing a laminate according to item 4.