JPS5812857B2 - Toumei Dunnetsu Sheet - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a transparent heat insulating sheet used for a simple agricultural greenhouse or a window curtain of a building, and aims to improve the heat insulating properties of this type of sheet.

Conventionally, simple agricultural greenhouses (vinyl greenhouses) are made of vinyl chloride film stretched in a semi-cylindrical shape, but as the heat escapes from the vinyl chloride film is extremely large, it is necessary to heat the greenhouse in winter with a kerosene-fired boiler, etc. The cost of equipment and fuel for this heating significantly reduced the profits of greenhouse cultivation.

In addition, ordinary vinyl chloride film is highly electrostatic, so
Dust easily adheres to it, and the transmittance of sunlight decreases to about 1 in 6 months.
The vinyl chloride film had to be replaced almost every year due to problems such as a decrease in mechanical strength due to deterioration due to ultraviolet rays and heat, and a tendency to tear.

Furthermore, in recent years, research has been conducted on selectively permeable films that are coated with so-called permselective membranes that allow sunlight to pass through the surface of plastic films, but reflect heat rays with longer wavelengths. is used in place of the above-mentioned vinyl chloride film to reflect and return the heat rays radiated from the ground surface or air inside the greenhouse, thereby reducing energy loss due to heat radiation and improving the heat retention of a simple agricultural greenhouse. is possible.

However, in this case, because the moist, warm air inside the greenhouse comes into contact with the film that has been cooled by the cold air outside, the inner surface of the film, that is, the surface of the selectively permeable membrane, is heavily condensed and is constantly wet with water. Since this attached moisture absorbs most of the heat rays, the heat ray reflection effect of the selective transmission film is significantly reduced.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to obtain a transparent heat insulating sheet that has high heat insulation properties and heat ray reflection effects and has a long life.

The present invention will be described below with reference to drawings showing embodiments thereof.

In Figure 1, 1 and 2 are polyester, polyethylene, polycarbonate, polymethyl methacrylate,
It may be a film that is transparent to sunlight, such as vinyl chloride, and exhibits some light absorption in the wavelength region of sunlight.

Note that when used for curtains, it may be better to use a film with an appropriate color.

3 is a selective transmission film that transmits sunlight well and reflects long wavelength heat rays.

Most of the energy of sunlight is in the wavelength range of 0.3 to 2μ, while the heat rays radiated from objects with surface temperatures of 0 to 100℃ have long wavelengths of 2 to 30μ, so the wavelength is approximately A material that transmits light with a wavelength of about 2 μm or less and reflects light with a wavelength of about 2 μm or more may be used.

Materials with such characteristics include metal oxide semiconductors such as indium oxide and tin oxide, multilayer interference films containing metal layers, and multilayer interference films consisting only of dielectrics.

Metal oxide semiconductors such as indium oxide and stannic oxide are
A method in which a metal such as indium or tin is vacuum-deposited or ion-plated onto a film in high-frequency oxygen plasma to form a thin film, or a method in which indium oxide or stannic oxide is vacuum-deposited on a film in an oxidizing atmosphere. It is formed by a method of performing a treatment such as heating in an oxidizing atmosphere, or by a method of applying a mist of a gas or solution of a halide such as indium or tin or an organic compound to the surface of a film heated in an oxidizing atmosphere.

In addition, as a multilayer interference film containing a metal layer, Al-Si
O2-Al-SiO2, which is made by laminating metal and dielectric thin films alternately, and F2-ZnSAI ZnS.
There are some, such as Ichihato F2, in which a metal layer is sandwiched between multiple dielectric layers.

Furthermore, as a multilayer interference film made only of dielectric material, ZnS
-MgF2- There are materials such as ZnS-MgF2 in which dielectric layers having different refractive indexes are alternately laminated.

In addition, the simplest structure is A thinly vacuum-deposited A with a thickness of about 5 to 200 Å, preferably 20 to 100 Å.
Although metal films such as I and Au have inferior properties (low transmittance of sunlight) compared to the various materials mentioned above, they still have selective properties, and are used for curtains to block direct sunlight to a certain extent. It is applicable because it is often desirable to be able to shield.

In FIG. 1, 4 is a bonding point of the films 1 and 2 by thermocompression bonding or ultrasonic welding, and 5 is a bonding point of the films 1 and 2.
The gas reservoir 5 is filled with air or a gas with lower thermal conductivity than air, such as carbon dioxide, freon, krypton, etc. If this filled gas is carbon dioxide, a heat insulating sheet is used. The thermal conductivity of gas is approximately 80% of that of air-filled gas, and 70% of that of krypton gas.
, and the insulation properties become even better.

The individual size of the gas reservoirs 5 should not be too large, as the thermal conductivity increases when convection occurs within them, and in order to prevent such convection, the thickness of the gas reservoirs 5,
At least one of the length and width is preferably 10 cm or less (preferably 5 cIrL or less).

In the embodiment shown in FIG. 1, two layers of sunlight-transparent film are pasted together, but it goes without saying that three or more layers of film may be pasted together.

FIG. 2 shows another embodiment of the present invention, 6, 7, 8
9 is a transparent film, 9 is a selectively permeable membrane, and 10 is a gas reservoir.

In addition, the selectively permeable membrane is not necessarily applied only to the outermost surface as shown in FIGS. Even if the selectively permeable membranes 13 and 14 are coated, high thermal insulation properties can be obtained due to the low thermal emissivity of the selectively permeable membrane.

Note that 15 is a gas reservoir.

As is clear from the above embodiments, the transparent heat insulating sheet of the present invention consists of two or more films that transmit solar rays and are pasted together so that a gas pocket is formed between each film, and at least one of the films A selective transmission film is formed on the surface of a sheet of film to effectively transmit solar rays and reflect long-wavelength heat rays, and provides the following effects.

(1) Because the gas pocket has a high insulation effect as a so-called gas insulation material, it has much better heat retention than conventional vinyl chloride film, and as gases, carbon dioxide and freon have lower thermal conductivity than air. If a gas such as , krypton or the like is used, the insulation properties will be further improved.

(2) When a simple agricultural greenhouse is made using the transparent heat insulating sheet of the present invention instead of vinyl chloride film, the indoor side of the sheet is not cooled much by the cold air outside, so dew condensation occurs on this side. Because of this, the selective permeation membrane is fully effective and reflects back the heat rays radiated from the heater, the ground surface of the greenhouse, or the air, significantly reducing heat loss. heating costs can be significantly reduced.

(3) Transparent conductive materials such as indium oxide and tin oxide, or materials with high surface conductivity such as multilayer interference containing metal layers are often used as selectively permeable membranes, so that the sheet does not become charged. ＜Dust does not easily adhere to the surface, and high transparency is maintained over a long period of time.

(4) Since the film is laminated in multiple layers, it is flexible and its mechanical strength does not deteriorate easily.Furthermore, even if it breaks in one place, the tear will continue to grow, making it difficult to form a complete through hole, so However, the insulation properties only slightly decrease.

(5) When the transparent heat insulating sheet of the present invention is used in window curtains for houses and buildings, it allows sunlight to pass through, reflects and returns heat rays from indoor heaters, etc., and blocks cold air near the window glass. It significantly increases the indoor heating effect, and blocks the hot air near the window glass in the summer.Furthermore, the selectively permeable membrane has a low thermal emissivity, so it can also reduce the heat radiation toward the room, improving the cooling effect. can be increased.

Furthermore, by appropriately selecting the size and shape of the gas reservoir, it is possible to avoid seeing through the room from the outside.

[Brief explanation of drawings]

FIG. 1, FIG. 2, and FIG. 3 are sectional views of transparent heat insulating sheets showing embodiments of the present invention, respectively. 1, 2, 6, 7, 8, 11, 12...Sunlight transparent film, 3, 9, 13, 14...Selective transmission membrane, 5
, 10, 15...Gas pool.

Claims (1)

[Claims] 1 Two or more layers of films that transmit solar rays are pasted together so that gas pools are formed between the films, and at least one of the films has a surface that is transparent to sunlight. A transparent heat insulating sheet characterized by forming a selective transmission film that reflects long wavelength heat rays.