JPS6159903B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an improved method for manufacturing a laminate having selective light transmission, and more particularly, the present invention relates to an improved method for manufacturing a laminate having selective light transmission, and more particularly, the present invention is comprised 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. The present invention relates to an improved method of manufacturing a laminate. The transparent conductive film has selective light transmittance, that is, it is transparent to light in the visible light range, and has the ability to reflect light with longer wavelengths than near-infrared light, so it is useful as a transparent heat insulating film. be. So solar energy collector,
It can be used in 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 conductive metal films such as gold, silver, copper, palladium, etc. that are made selectively transparent over a certain wavelength range. For example, a 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 , ZnS/ Ag/ZnS or
A laminate with 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 tends to deteriorate in performance in a high temperature environment, and it is difficult to maintain its performance stably for a long period of time. is often the case. 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 selective light transmittance without such drawbacks, the present inventors have found that by providing a protective coating containing a sulfur compound on a transparent conductive film, at least the metal layer can be removed. It has been discovered that a metal layer treated with a sulfur compound can be formed at the interface, and the above-mentioned drawbacks can be greatly improved, and the present invention has been achieved. That is, the present invention provides the following features: 1. On at least one side of the transparent molded substrate A, a transparent high refractive index dielectric thin film layer B, a metal thin film layer C made of silver or an alloy of silver, a transparent high refractive index dielectric thin film layer D, and In the production of a laminate in which protective layers E are sequentially laminated, the protective layer E provided on the transparent high refractive index dielectric thin film layer D is made of thiourea or thiourea having a sulfur atom active against silver. number of carbon atoms
A method for producing a laminate, characterized in that the laminate is formed by applying a protective coating liquid containing at least one sulfur compound selected from the group consisting of derivatives with 20 or less hydrocarbon groups. 2 The transparent high refractive index dielectric thin film layer B and/or D
The method for producing a laminate according to item 1 above, wherein is a titanium oxide thin film layer formed by hydrolysis of an alkyl titanate. SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide an improved method for producing a laminate having selective light transmission by treatment with a sulfuric acid compound. 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 arbitrary shapes such as plate, sheet, film, and rod shapes. However, sheet-like, film-like, and plate-like products are preferable from the viewpoint of processability.
Among these, film-like materials are particularly preferred 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 it is 1.7 or more for visible light. , preferably has a refractive index of 1.8 or more, visible light transmittance 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 sulfide, 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. Particularly, 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, and in particular when it is made of alkyl titanate. This is the case when a titanium oxide thin film layer 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. Examples of alkyl titanates include tetrabutyl titanate, tetraethyl titanate, tetrapropyl titanate, diisopropoxy titanium, bisacetylacetonate, etc.
In particular, tetrabutyl titanate and tetrapropyl titanate are preferably used. 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. The metal constituting the metal thin film layer C is silver or a silver alloy. Typical metals that can be contained in silver (Ag) include gold (Au), platinum (Pt), and copper (Cu), but other metals may be used as long as they do not impair the effects of the present invention or the performance of the laminate. It may contain the following ingredients. 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 reflective ability or conductivity, it must be at least in a certain range. It is necessary to have continuity. In order to have a continuous structure, the film thickness must be approximately
The thickness is required to be 40 Å or more, and preferably 500 Å or less from the viewpoint of transparency to solar energy. The thinner the metal thin film, the better the visible light transmission, so to increase transparency it is best to have a film thickness of 250 Å or less, and to have sufficient infrared reflection ability, 50 Å.
The above film thickness is preferable. The metal thin film layer C can be formed by vacuum evaporation, sputtering, plasma spraying, vapor plating, chemical plating, or a combination thereof. Among these methods, a method suitable for the substrate may be used. 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. Examples of thiourea derivatives include those in which the hydrogen atom of an amino group is substituted with a hydrocarbon group, for example, a hydrocarbon group having 20 or less carbon atoms, such as allylthiourea, N-
Benzylthiourea, N-methylthiourea, N.
N'-dimethylthiourea, N-ethylthiourea,
N・N′-diethylthiourea, N-butylthiourea, N-phenylthiourea, N・N′-diphenylthiourea and N-ethylidenethiourea, N・
Examples include N'-cyclohexylthiourea and N-cyclohexylthiourea. In the present invention, the protective layer E is formed by applying a protective coating liquid containing the sulfur compound onto the transparent refractive index layer D. Such a protective coating agent only needs to be transparent, inert, and compatible with the sulfur compound. Suitable examples include acrylic resin, polystyrene resin, polyvinyl formal, polyvinyl butyral, polyvinyl chloride, vinyl resins such as polyvinyl chloride monoacetate copolymer, polyurethane, epoxy, alkyd, unsaturated polyester, and silicone. Examples include resin. A more specific explanation of the present invention will be given in the following examples. In the examples, unless otherwise specified, the light transmittance is a value at a wavelength of 500 nm. 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 silver (approximately 3000 Å) vacuum-deposited.
Measured as 100%. Examples 1 to 4 A biaxially stretched polyethylene terephthalate film with a light transmittance of 86% and a thickness of 50μ has a thickness of 300Å as the first layer.
A layer of titanium oxide, a silver layer with a thickness of 160 Å as a second layer, and a titanium oxide layer with a thickness of 300 Å as a third layer are sequentially laminated on the film to form a laminate having transparent conductivity and selective light transmittance. Ta. The first and third titanium oxide thin film layers each contain 1 part of tetramer of tetrabutyl titanate, 1 part of acetylacetone, and 26 parts of isopropyl alcohol.
Apply a solution consisting of
Heat for 3 minutes and set aside. The silver layer was provided by vacuum deposition using a resistance heating method. The laminate composed of polyethylene terephthalate film/titanium oxide layer/Ag layer/titanium oxide layer produced in this manner will be hereinafter referred to as laminate A. A solution of 1 part of polyacrylic resin (Dianal LR574, Mitsubishi Rayon Co., Ltd.) mixed with 1 part of methyl isobutyl ketone and a predetermined proportion of 1,3-diphenyl-2-thiourea was added onto this laminate. , 2μ was applied using a bar coater and dried at 120°C for 3 minutes. The thus obtained laminate was subjected to a heat resistance test using a hot air dryer at 90°C, and changes in heat resistance were tracked by changes in infrared reflectance, and the time required for the reflectance to drop to 85% or less of the initial value was measured. was determined as the deterioration time. For reference, the results without addition are also shown. The results are shown in Table-1. The amount added herein means the weight fraction (%) of 1,3-diphenyl-2-thiourea based on the solid content of the polyacrylic resin.

[Table] Examples 5 and 6 1-phenyl-2thiourea and methylthiourea were used instead of 1,3-diphenyl-2-thiourea.
Added at a ratio of 5wt% to the solid content of LR574 resin,
A 2μ coating was applied on the laminate ○I, and a 90°C heat resistance test was similarly conducted.

[Table] Example 7 Using water-soluble acrylic emulsion (Asahipen Co., Ltd., water-based varnish) instead of LR574, thiourea was added at a ratio of 5% to the solid content of the acrylic resin, and 2μ Coating and the same
A 90°C heat resistance accelerated test was conducted. As a result, the deterioration time was 400 hours. Example 8 In the laminate ○A, a Ag-Au alloy (5% by weight of Au) was sputtered to 160 Å instead of the silver layer, and in the same manner as in Example 4, 5% of LR574 was applied.
% of 1,3-diphenyl-2-thiourea was added, a 2μ coating was applied, and a heat resistance test at 90°C was conducted. The deterioration time was 2300 hours.

Claims (1)

[Claims] 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 made of silver or an alloy of silver, and a transparent high refractive index dielectric thin film layer D In the production of a laminate in which the protective layer E and the protective layer E are sequentially laminated, the protective layer E provided on the transparent high refractive index dielectric thin film layer D is made of thiourea, thiourea and thiourea having a sulfur atom which is active against silver. Production of a laminate, characterized in that it is formed by applying a protective coating liquid containing at least one sulfur compound selected from the group consisting of dielectrics made of hydrocarbon groups of urea having 20 or less carbon atoms. Method. 2 The transparent high refractive index dielectric thin film layer B and/or D
2. The method for producing a laminate according to claim 1, wherein said layer is a titanium oxide thin film layer formed by hydrolysis of an alkyl titanate.