JPS6226310B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a selective light transmitting laminate, and more particularly to a selective light transmitting laminate having high visible light transmittance, high solar energy transmittance, and excellent scratch resistance. As the selective light transmitting laminate, for example, one that is transparent to visible light and reflective to infrared light is used as a transparent heat insulating film. Laminated bodies with such performance can be used in solar energy collectors, water heaters,
Possible uses include greenhouses, building windows, refrigeration and refrigerated cases, vehicle and aircraft windows, etc.
The function of transparent insulating windows that utilize solar energy and prevent energy dissipation will become increasingly important in the future. In order to achieve this objective, it is strongly desired that homogeneous, high-performance selective light transmitting laminates be industrially available at low cost and in large quantities. Conventionally, films (laminates) having the above-mentioned performance include: 1. A metal thin film of gold, silver, copper, aluminum, etc. 2. A metal thin film of gold, silver, copper, aluminum, etc.;
Improved transparency in a certain wavelength range by combining with other elements. 3 Compound semiconductor films made of indium oxide, tin oxide, copper iodide, etc. are known. In particular, a typical structure of the above 2 is a laminate in which a metal thin film layer is sandwiched between transparent high refractive index thin film layers, and is formed by, for example, vacuum evaporation, reactive evaporation, chemical coating method, or sputtering method.
Bi ₂ O ₂ /Au/Bi ₂ O ₃ , ZnS/Ag/ZnS or TiO ₂ /
Laminated bodies such as Ag/TiO ₂ have been proposed. However, when using a laminate with selective light transmittance as a transparent cross-sectional window, it is important not only to have the inherent performance such as visible light transmittance and infrared light reflectivity, but also to have abrasion resistance and durability (light resistance, Practical performance such as heat resistance) is also required. However, in general, laminated extremely thin metal films or metal oxide thin films as described above often have insufficient wear resistance, and even when used in double-glazed glass, for example, during construction, Touching the coated surface with your fingertips tends to cause discoloration or scratches, and especially when it is directly exposed to the outside, it is necessary to provide a protective layer. However, when a transparent polymeric protective film was laminated onto these selectively permeable thin films, it was found that the visible light transmittance and solar energy transmittance decreased by about 10% unless appropriate conditions were selected. . When the selectively permeable thin film is applied to south-facing double windows in Sapporo, in energy saving calculations for heating, if the transmittance of Maruyo Energy increases by 1%, the energy savings will be 40 yen/m2 per ^1m2 of window area. The results show an increase of ² years. Therefore, in a building with a glass window area of 10 ^m2 , a decrease in solar energy transmittance of about 10% means an energy saving of 4000 m2.
This means that yen/year will also be lost. In addition, a decrease in visible light transmittance causes a psychological pressure on residents and reduces the window's function. The present inventors investigated a method of providing a selective light transmitting thin film layer on a polymer protective film layer without reducing solar energy transmittance and visible light transmittance, and found that the thickness of the metal thin film layer By limiting the thickness of the polymer protective film to a certain range, a laminate with improved wear resistance, etc. can be obtained without reducing visible light transmittance and solar energy transmittance. This discovery led to the present invention. That is, the present invention has the following features: 1. One or two high refractive index dielectric thin film layers and metal thin film layers are laminated on at least one side of a transparent molded substrate, and a polymer transparent protective layer is further laminated thereon. It is a laminate having selective light transmittance, and the film thickness d (μm) of the polymer transparent protective layer
However, for the thickness l (Å) of the metal thin film layer, the following formula (1)
This is a coated laminate characterized by satisfying (3). (1) At 35≦l<130, 0.05<d<9 (2) At 130l<180, 0.05<d<-0.052l+9.76 (3) At 180l<300, 0.05<d<0.4 Regarding the thickness of the metal thin film layer. For example, the film thickness is 35Å
If it is less than 300 Å, the metal will not be deposited continuously and will take an island-like structure, resulting in insufficient heat ray reflection ability. If it is more than 300 Å, the thickness of the metal layer will be too thick and the visible light transmittance will be less than 40%, making it impractical. I can't offer it. Examples of the transparent molded substrate that serves as the base of the selectively transparent laminate used in the present invention include polyethylene terephthalate resin, polyethylene naphthalate resin, polybutylene terephthalate resin, polycarbonate resin, polyvinyl chloride resin, and acrylic resin. , polyamide resin, polyethylene resin, polypropylene resin, and molded products of other resins. These molded products can be molded into any shape such as a plate, sheet, or film, and colored or uncolored transparent ones are selected depending on the purpose. However, sheet-like, film-like, and plate-like materials are preferable from the viewpoint of processability, and among them, film-like materials are particularly preferable from the viewpoint of productivity. Further, a biaxially oriented polyethylene terephthalate film is preferable from the viewpoints of transparency, film strength, dimensional stability, adhesiveness with a laminate, and the like. Moreover, polypropylene film is one of the preferable films since its infrared absorption rate is low. Examples of the high refractive index dielectric thin film layer used in the present invention include thin film layers made of titanium dioxide, titanium oxide, bismuth oxide, zinc sulfide, tin oxide, indium oxide, and the like. The high refractive index dielectric thin film layer has a refractive index of 1.6 or more, preferably 1.8 or more with respect to visible light, and a visible light transmittance of 80% or more, preferably 90% or more. Thickness is 50-600Å, preferably
It is 120-400 Å. These thin film layers can also be applied by sputtering, ion plating, vacuum deposition or chemical coating. As an example of a chemical coating, a thin layer of titanium oxide can be provided, for example by applying an organic solution of a solute based on an alkyl titanate. By adjusting the conditions for alkyl titanate film formation, those in which 0.1 to 10% by weight of alkyl groups remain in the thin film layer have improved adhesion with metal layers or organic films, and can be used in a wide wavelength range. This is particularly preferred since it provides a selectively transparent film with excellent transparency throughout the film. The high refractive index dielectric thin film layer may be provided between the transparent molded substrate and the metal thin film layer, or between the metal thin film layer and the polymer transparent protective layer. Alternatively, a metal thin film layer may be sandwiched between high refractive index dielectric thin film layers. Silver, gold, copper, alloys or mixtures thereof, or multilayer laminates are used as materials for the metal thin film layer constituting the selectively transparent film used in the present invention. Particularly preferable metal thin film layers include a silver-copper alloy layer, a silver-gold alloy layer, a gold layer, and a gold-silver alloy layer, all of which have a thickness of 35 to 300 Å. These alloy layers are preferred examples in terms of durability. Examples of methods for forming the metal thin film layer include vacuum evaporation, cathode sputtering, plasma spraying, vapor phase plating, chemical plating, electroplating, and combinations thereof. The vacuum evaporation method is advantageous in that vapor deposition is performed efficiently, and the sputtering method is advantageous in that temporal fluctuations in the composition of the metal thin film can be reduced. Materials used for the polymeric transparent protective layer include, for example, poly(meth)acrylate paints; saturated polyester paints; ethylene-vinyl acetate copolymer paints; polystyrene paints; polyvinyl formal or polyvinyl butyral paints; polyvinyl chloride; Examples include vinyl chloride paints such as vinyl acetate-vinyl chloride copolymer or vinyl chloride-vinylidene chloride; alcohol-soluble nylon; and polyolefins such as polyethylene or polypropylene. In particular, poly(meth)acrylate paints mainly composed of (meth)acrylic acid esters of higher aliphatic alcohols such as 2-ethylhexyl alcohol and butyl alcohol; linear or branched paints such as ethylene glycol, tetramethylene glycol, neopentyl glycol, etc. Mainly from aliphatic diols such as adipic acid, aliphatic dicarboxylic acids such as sebacic acid, or ε-oxycaproic acid, certain saturated polyester resin paints; ethylene-vinyl acetate copolymer paints; acrylonitrile-
Styrene copolymer; polystyrene; alcohol-soluble nylon made of aliphatic polyamide copolymer, acrylonitrile, methacrylonitrile,
Polypropylene polyethylene and the like are preferably used. In addition, for applications that require particularly scratch resistance, polyfunctional poly(meth) is used as a transparent polymer film.
Examples include three-dimensional crosslinked films such as acrylate paints and diethylene glycol bisallyl carbonate; three-dimensional crosslinked films obtained by heating and curing thermosetting resin paints such as melamine resin paints. Generally, the visible light transmittance, solar energy transmittance, etc. of a laminate of metal thin film layers and dielectric layers are determined by the optical properties of the individual components of the laminate, such as the refractive index,
If the wavelength dependence of the absorption rate is known, it can theoretically be calculated based on a known method. However, based on the actual calculations, it was found that the prepared samples differed from the predicted values. One of the major reasons for this is that as long as a polymer film is used as a substrate, there is a limit to its surface uniformity, and therefore the thickness of the film laminated on it is constant from a macroscopic perspective. but,
We predict that this is due to the difference in film thickness in microscopy. Therefore, by simple calculation,
It is not possible to predict the preferred film thickness, and a preferred laminate can be obtained by actually examining samples under various conditions. Regarding the present invention, only when the thickness of the metal layer and the transparent polymeric protective film satisfy certain conditions can a selective light transmitting film with improved scratch resistance be obtained without decreasing solar energy transmittance. I understood. That is, as mentioned above, the thickness of the metal thin film layer is set to l (Å).
When, the film thickness d (μm) of the polymer transparent protective layer is
satisfies the following equations (1) to (3). (1) For 35≦l<130, 0.05<d<9 (2) For 130l<180, 0.05<d<-0.052l+9.76 (3) For 180l<300, 0.05<d<0.5 However, polymer transparent Protective layer thickness d(μ
When m) is in the range of 0.4 to 1.5, interference patterns may occur depending on the type of metal layer and high refractive index dielectric thin film layer, so it is necessary to carefully provide the interference pattern depending on the material used. As described above, by appropriately providing a protective layer, it is possible to obtain a selectively transparent film with increased solar energy transmittance and improved scratch resistance. The thus obtained laminate can be applied as a transparent heat insulating film inside a multi-layer window or attached to a single-pane window.
Alternatively, the heat insulation properties of building windows can be improved by hanging them on the inside of windows as rolled curtains. Furthermore, energy saving can be achieved by applying it to the openings or windows of refrigerator and refrigerator cases. For example, when applied to a four-sided glass case, an energy saving effect of approximately 20% can be achieved. The laminate of the present invention is excellent in that there are few scratches and the solar energy transmittance does not decrease during construction and use. Hereinafter, a more specific explanation of the present invention will be shown in Examples. The solar energy transmittance is calculated from the literature Moon, P., Journal of Franklin Institute (Moon, P., J.Franklin Inst.
) vol.203 583 (1940). Calculated using the solar spectrum weights. The elemental composition and film thickness in the thin film were determined by quantitative determination using a fluorescent X-ray analysis method (using a Rigaku fluorescent X-ray analyzer). Regarding thick films,
Measured using a digital electronic micrometer (K351A type) manufactured by Anritsu Electric. Scratch resistance was determined using the clock meter test method. Commercially available gauze was used on the friction surface of a clock meter (manufactured by Toyo Seiki), and a load of 500 g/cm ² was applied to cause the sample surface to wear back and forth, and the number of back and forth cycles until the metal layer became worn was determined. Example 1 and Comparative Example 1 A biaxially stretched polyethylene terephthalate film with a light transmittance of 86% and a film thickness of 25 μm, a titanium oxide layer with a film thickness of 172 Å as a high refractive index dielectric thin film layer, and a silver thin film layer on top of the titanium oxide layer with a film thickness of 172 Å. , an alloy thin film of copper (composition ratio silver/copper = 92/8) was provided. On top of this, a titanium oxide layer with a thickness of 117 Å was further provided as a high refractive index dielectric thin film layer. The thickness of the metal thin film layer is 280
Å, 208Å, 162Å, 131Å, 80Å, 30Å. These samples were further made with polymethacrylonitrile having various thicknesses as transparent polymer protective layers. The titanium oxide layer was provided by hydrolyzing tetrabutyl titanate. The metal thin film layer has a pressure of 5×
Produced by sputtering method at 10 ^-3 Torr. The solar energy transmittance of the obtained sample was measured and the results are shown in Table-1. In addition, the number of times the clock meter was reciprocated for the sample without the polymer transparent protective layer was 1 to 2 times, but the number of times the clock meter was reciprocated was 10 to 14 times for the sample with a 0.1 μm transparent polymer protective layer. improved by one digit. Furthermore, the one with 2μ of polymer transparent protective layer is 3000
It showed an excellent value of ~4000 times.

[Table] Example 2 Gold was provided as a metal thin film layer by vapor deposition on a biaxially stretched polyethylene terephthalate film having a light transmittance of 86% and a film thickness of 25 μm. Gold film thickness is 44 Å, 57 Å, 58 Å, 94 Å, 156
Å, changed to 196Å. On top of this, a TiO ₂ film obtained by hydrolyzing tetrabutyl titanate is deposited as a high refractive index dielectric layer with a thickness of 150 Å.
The thickness was set at . Furthermore, polyacrylonitrile was coated with various thicknesses as a polymer transparent protective layer on top of this. Table 2 shows the results obtained by testing in the same manner as in Example 1.

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Claims (1)

[Claims] 1. One or two high refractive index dielectric thin film layers and metal thin film layers are laminated on at least one side of a transparent molded substrate, and a polymer transparent protective layer is further laminated thereon. The film thickness d (μm) of the polymer transparent protective layer is expressed by the following formulas (1) to (3) with respect to the film thickness l (Å) of the metal thin film layer. A coated laminate characterized in that it satisfies the following. (1) At 35≦l<130, 0.05<d<9 (2) At 130l<180, 0.05<d<-0.052l+9.76 (3) At 180l<300, 0.05<d<0.4