JPS629421B2 - - 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 excellent durability. A representative example of selective light transmitting laminates is a laminate with heat ray reflecting ability, which is highly transparent to visible light and highly reflective to far infrared rays. It has begun to be used in various fields for the effective use of solar energy and energy dissipation. However, in order to be used in such fields, it is necessary not only to be industrially produced in large quantities and at low cost, but also to have sufficiently satisfactory durability. Conventionally, various selective light transmitting laminates have been proposed. For example, gold and
It is known that a metal thin film such as silver, copper, or aluminum is provided alone or in combination with a transparent high refractive index thin film layer. Furthermore, since the laminate having the above structure has poor abrasion resistance, it has also been proposed to further provide an abrasion resistant protective layer thereon. However, when such a laminate is applied to windows of buildings or show cases, spot-like stains occur after a while. This is particularly noticeable in laminates that are attached to windows that are prone to condensation or that are cleaned with tap water or the like. The present inventors attempted to suppress the occurrence of the spots by coating the surface with a polyacrylic resin or polyacrylonitrile resin effective as an abrasion resistant material to a thickness of 2 to 10 .mu.m, but this was not possible. It may be possible to suppress the occurrence of spots by coating these effective wear-resistant materials even thicker, but in that case, the amount of far-infrared rays absorbed by the coated protective layer will be This has the disadvantage that the thermal insulation performance decreases due to a significant increase in the thermal resistance. The inventors of the present invention conducted extensive research into a speckling protective film that does not suffer from such drawbacks, and as a result, they discovered that a specific substance satisfies these requirements, and have thus arrived at the present invention. That is, the present invention provides (1) a selective light transmitting laminate comprising a transparent molded substrate, a selective light transmitting functional layer having at least a metal thin film layer provided thereon, and a transparent protective layer; 2. A selectively light-transmitting laminate comprising, as a base layer, at least one water-active polymer compound selected from the group consisting of pyrrolidone, gelatin, glue, casein, and urea-based adhesives; and 2. the metal thin film. The selective light transmitting laminate according to item 1 above, wherein the layer is a metal thin film layer containing silver as a main component. The basic structure of the laminate of the present invention is a transparent molded substrate (A), a selective light transmitting functional layer (B) having at least a metal thin film layer provided thereon, and a transparent protective layer (C).
It consists of. The transparent molded substrate (A) and selective light transmitting functional layer (B) will be described later, but in the present invention, the transparent protective layer (C) is

The main feature is that it contains a water-active polymer compound having a bonding unit of the formula: Here, "water-active" refers to so-called water-soluble materials, materials that swell with water, and even materials that are water-soluble during membrane formation but become water-insoluble through post-treatment. Examples of such polymeric compounds include glue, gelatin, casein, albumin, polyvinylpyrrolidone, urea-based adhesives, copolymers containing structural units thereof, and mixtures thereof.

The bonding group represented by the formula is present in the main chain and/or side chain of the water-active polymer, and the number thereof must be at least 30% of the repeating units. These water-active compounds can be used alone or in a mixture with non-water-active compounds. The film thickness of the transparent protective layer (C) needs to be at least 0.01 μm as a film of the water-active compound alone, and if the thickness is less than this, it is difficult to exhibit the effect, and if the film thickness is 20 μm or more, , the infrared absorption ability of the transparent protective layer (C) increases, making it impossible to obtain excellent heat insulation performance. It is effective for the transparent protective layer (C) of the present invention to have scratch resistance and abrasion resistance in addition to the spot-suppressing effect of the above-mentioned specific compound. Alternatively, it can be used in a separate layer from the specific compound. With such combination,

It is possible to prevent dissolution loss of a water-active polymeric component having a structural unit of the formula: Such substances include various organic and inorganic compounds. Examples of organic compounds include polyethylene terephthalate, polyethylene, polypropylene, polycarbonate, polyacrylonitrile, polymethacrylonitrile, and poly(meth)acrylate ethylene. Examples include vinyl acetate copolymer, polystyrene, polyvinyl chloride, vinyl acetate-vinyl chloride copolymer, vinyl chloride such as vinyl chloride-vinylidene chloride, nylon, polyfunctional poly(meth)acrylate, diethylene glycol bisallyl carbonate, melamine, etc. is,
Examples of inorganic compounds include metal oxides such as silicon oxide, alumina, magnesia, and zirconia. In order to improve scratch resistance and abrasion resistance, the thickness of these protective films should be at least
It is necessary that the thickness be 0.01 μm or more. The maximum film thickness is
The smaller the infrared absorption ability of the protective film, the larger it can be made. Preferably the infrared wavelength is 4 to 20μm
Infrared reflectance R of selective light transmitting laminate at 300
The black body radiation energy E at 〓 is ΣR×E/
It is preferable to provide a protective film so as to satisfy the formula ΣE0.6. For example, in the case of polyethylene coatings, 40 μm or less is advantageous, and in the case of polymethylacrylonitrile coatings, 15 μm or less is advantageous. The transparent protective layer (C) as a whole is

A mixed system of a water-active polymer compound having a bonding unit of the formula and a substance for improving scratch and wear resistance, and/or

It is conceivable to layer a substance to improve scratch resistance and abrasion resistance on a water-active polymer compound having a bonding unit of the formula. The transparent molded substrate (A) may be made of either an organic compound or an inorganic compound. Examples of materials made of organic compounds include films and sheets of organic polymer compounds, and examples of materials made of inorganic compounds include glass plates. The selective light transmitting functional layer (B) contains at least a metal thin film layer, and the metal thin film layer includes:
Examples include a single thin film of gold, silver, copper, or aluminum, an alloy thin film of two or more of these, or a multilayer thin film thereof. Among these, silver-copper alloy thin films and silver-gold alloy thin films are preferred. The thickness of the metal thin film layer is not particularly limited as long as it has transparent conductivity or selective light transmittance, but is usually about 40 mm.
The thickness is preferably from Å to 500 Å, and particularly preferably from 60 Å to 200 Å in order to have both sufficient transparency and sufficient conductivity. When the thickness is less than 40 Å, it tends to form an island-like structure, and when it is more than 500 Å, transparency is impaired.
Examples of means for forming such a metal thin film include vacuum evaporation, cathode sputtering, ion plating, and plasma spraying.
Preferably, a vacuum evaporation method or a cathode sputtering method is used. The selective light transmitting functional layer (B) may have other layers in addition to the metal thin film layer, for example, in order to increase visible light transmittance or to improve adhesion. Such a layer may include, for example, a transparent high refractive index dielectric thin film layer. What is a high refractive index dielectric?
The refractive index measured at 589 nm is 1.4 or more, preferably 1.6 or more, more preferably
1.7 or higher. Examples of materials that satisfy these conditions include titanium monoxide, titanium dioxide, zirconium oxide, bismuth oxide, tin oxide, indium oxide, silicon oxide, zinc sulfide, and barium oxide. Among these, titanium oxide such as titanium monoxide and titanium dioxide, silicon oxide, and zinc sulfide are preferable from the viewpoint of transparency and film formation speed.In particular, titanium oxide is preferable because of its excellent optical properties such as visible light refractive index and transparency. preferable. The transparent high refractive index thin film layer can be formed by either a physical method such as vapor deposition or a chemical method such as thermal hydrolysis. These have a film thickness of 50 to 1000 Å, preferably 100 to
It has a thickness of 500 Å and is provided on one or both sides of the metal thin film layer or in contact with the transparent protective layer. The laminate of the present invention is constructed by representing the transparent molded substrate (A) with A, the metal thin film layer with B-1, the transparent high refractive index dielectric layer with B-2, and the transparent protective layer (C) with C. If indicated, the following are preferred. (1) A/B-2/B-1/B-2/C (2) A/B-2/B-1/C/B-2 (3) A/B-2/B-1/C (4) A/B-1/B-2/C (5) A/B-1/C/B-2 The laminate of the present invention was also tested using the following equipment. Mounting Durability Test Apparatus The indoor glass surface of a 150 cm x 150 cm window facing south was used as the surface to which the laminate was attached, and a tap water spray nozzle was installed approximately 40 cm away from the surface. Tap water was jetted from the nozzle for 1 minute every 2 hours to wet the entire surface of the laminate almost uniformly. The tap water on the laminate is
It was dry by the time of the next injection. Hereinafter, the effects of the selective light transmitting thin film of the present invention will be specifically described based on Examples. Example 1 A solution consisting of 3 parts of tetrabutyl titanate heptamer, 65 parts of isopropyl alcohol, and 32 parts of n-hexane was applied onto a transparent biaxially stretched polyester film using a bar coater, and heated to 120°C for 5 minutes. A 250 Å thick titanium oxide layer is provided, and a 180 Å thick silver and gold alloy layer (silver/gold = 80/
20) was installed using the sputtering method. Gelatin dissolved in a mixture of water and isopropyl alcohol (3 parts of water to 1 part of isopropyl alcohol) was applied onto this using a bar coater to form a film with a thickness of 0.1 μm. Furthermore, a cyclohexanone solution of polymethylacrylonitrile was applied onto this using a bar coater to form a film having a thickness of 2 μm. The obtained selective light transmitting thin film was attached to the window of a mounting durability test device. In the laminate of this example, no spot-like stains occurred even after 50 days. The average infrared reflectance at infrared wavelengths from 4 to 30 μm was 84%. Comparative Example 1 A selective light transmitting laminate was produced which was exactly the same as in Example 1 except that it was not coated with a gelatin film. When pasted on the window of the mounting durability test equipment, 7
After a few days, many spots appeared. Example 2 The selective light transmitting laminate obtained in Example 1 was further immersed in a 5% concentration formalin solution for 1 minute to further increase its water resistance, and was similarly attached to the window of a mounting durability testing device. No spot-like stains were observed even after 30 days. It also had an infrared reflectance of 82%. Example 3 A TiO ₂ film was provided on a transparent biaxially stretched polyester film by an electron beam method. The film thickness was 240 Å. On top of this is a metal thin film layer with a thickness of 170 Å.
A layer of silver and gold alloy (silver/gold = 80/20) was formed by sputtering. On top of this, a film thickness of 240 Å is added.
A TiO ₂ film was deposited using an electron beam method. Furthermore, a polyvinylpyrrolidone solution dissolved in isopropyl alcohol was applied on top of this using a bar coater to provide a polyvinylpyrrolidone film having a thickness of 0.4 μm. On top of this, a 1.5 μm thick film of polymethyl acrylonitrile was provided as a polymer transparent protective layer. When the thus obtained selective light transmitting laminate was put into a mounting durability tester and tested, it was found that 50
No spots appeared even after a day had passed. Moreover, the average infrared reflectance was 80%. Comparative Example 2 A selective light transmitting laminate similar to that of Example 3 was prepared except that it was not coated with a polyvinylpyrrolidone film. When the laminate was placed in a mounting durability testing device, countless spots appeared over a period of 7 days. Example 4 Applying albumin solution instead of gelatin
A selective light transmitting laminate was prepared in the same manner as in Example 1, except that a 0.3 μm film was formed. When applied to the window of a mounting durability testing device, no spots appeared even after 21 days, confirming that it was more than three times as effective.
In addition, the infrared reflectance was 82%. Example 5 On biaxially oriented polyethylene terephthalate, the thickness was
A 150 Å titanium oxide layer was provided. Furthermore, a 190 Å thick silver and copper alloy (silver/copper = 95/5) was deposited by sputtering. Apply approximately 0.5μ of urea adhesive on top of this.
It was provided with a film thickness of . Furthermore, on top of this, a film of polyacrylonitrile with a thickness of 2
A protective layer of μ was provided. When the resulting selectively transmitting thin film was subjected to a mounting durability test, it was found to be more than 5 times more effective. In addition, the infrared reflectance was maintained at 79%.

Claims (1)

[Scope of Claims] 1. A selectively transparent laminate comprising a transparent molded substrate, a selectively transparent functional layer having at least a metal thin film layer provided thereon, and a transparent protective layer; is polyvinylpyrrolidone,
1. A selectively transparent laminate, characterized in that it contains as a base layer at least one water-active polymer compound selected from the group consisting of gelatin, glue, casein, and urea-based adhesives. 2. The selective light transmitting laminate according to claim 1, wherein the metal thin film layer is a metal thin film layer containing silver as a main component.