JPH09174745A - Agricultural sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to shield infrared rays for a long time and to permeate visible rays and ultraviolet rays with excellent light resistance by providing an infrared rays shield layer using inorganic infrared ray shielding agent containing tin oxide as a main ingredient on a transparent base material sheet. SOLUTION: The agricultural sheet 10 comprises an infrared rays shield layer 12 on a transparent base material sheet 11 made of any of polyester, vinyl chloride, polyolefin resin sheets. The layer 12 is formed by coating the sheet 11 with coating liquid dissolved or dispersed in solution or dispersant containing transparent resin with infrared rays shielding agent as binder. The inorganic agent contains tin oxide of fine particles having a particle size of 500Å or less as a main ingredient, and, as required, one or more types of ingredients selected from copper oxide, zinc oxide, magnesium oxide, antimony oxide, iridium oxide, metal oxide belonging to the groups IVa, Va or VIa of the periodic table of the elements, gold, silver and carbon black in a range of 0.1 to 50wt%.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an agricultural greenhouse sheet for promoting the growth of plants, and more particularly to an agricultural greenhouse sheet that transmits ultraviolet rays and visible rays and blocks infrared rays.

[0002]

2. Description of the Related Art In recent years, in agriculture, for the purpose of optimizing the growth conditions of crops, adjusting the harvest time of crops, etc., crops are appropriately controlled in greenhouses, greenhouses, etc. The so-called institutional farming for growing rice is becoming more and more popular. In this institutional farming, there is a problem that the temperature in the room rises excessively in the summer, which adversely affects the growth of crops and may even lead to death.
There has been a strong demand for a means for suppressing the rise in indoor temperature in the summer, especially in warm regions.

A cooling method can be considered as a means for suppressing the indoor temperature rise, but it is too expensive and not practical. Moreover, the method of covering with Yoshizushi, a black film, a knitting net, etc., impairs the photosynthesis of crops due to the low transmittance of sunlight. Therefore, paying attention to the fact that the component of sunlight that contributes to a temperature rise is mainly infrared rays having a wavelength of 700 nm or more, and various means for shielding the infrared rays while transmitting the visible rays necessary for photosynthesis have been proposed.

For example, a water filter device (see Japanese Patent Publication No. 4-48404) in which an aqueous solution is sandwiched between two transparent plates, and a heat ray reflective film is sandwiched between transparent substrates (Japanese Patent Laid-Open No. 7-67479). (See Japanese Patent Application Laid-Open No. 1989), a transparent resin film containing or coating an organic near-infrared absorber (see Japanese Patent Application Laid-Open No. 50-51549), and a polyolefin resin containing calcium carbonate, silicate, aluminum hydroxide or the like. Kneaded and molded (Japanese Patent Publication No. 59-37)
No. 016), zinc oxide powder doped with aluminum, silicon, titanium or the like is made into a paint together with a resin and applied to a substrate, vapor-deposited / sputtered on the substrate, or kneaded into a resin and molded (special Kaihei 4-44721 and Japanese Patent Laid-Open No. 7-291680) are proposed.

However, the above-mentioned water filter device has a complicated structure, is heavy in weight, and is difficult to remove, and the heat ray reflective film is expensive because it is manufactured by a vapor deposition method. In addition, it partially blocks visible light rays. However, the organic near-infrared absorbing agent is expensive, and the light resistance is not sufficient, so that it needs to be replaced frequently. On the other hand, the one using an inorganic infrared absorbing agent is excellent in light resistance, but the one using calcium carbonate, silicate, aluminum hydroxide or the like is substantially transparent to near infrared rays having a wavelength of 3 μm or less. Is not suitable for the purpose of suppressing the increase in the indoor temperature in the summer, and a powder of zinc oxide doped with silicon, titanium, etc. is suitable for the purpose of suppressing the increase in the indoor temperature in the summer. However, this also blocks ultraviolet rays, so it is impossible to cultivate colored crops such as eggplant and flowers that require ultraviolet rays for growth, and pollination using insects such as bees that detect ultraviolet rays. There was a problem that the scope of application was limited.

[0006]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems relating to an agricultural sheet having an infrared ray shielding effect, and has a light resistance using an inorganic infrared ray shielding agent. It is an object of the present invention to provide an agricultural sheet which is excellent, shields infrared rays for a long time, and transmits visible rays and ultraviolet rays.

[0007]

The agricultural sheet of the present invention is characterized in that an infrared shielding layer using an inorganic infrared shielding agent containing tin oxide as a main component is provided on a transparent substrate sheet. I am trying.

In the agricultural sheet of the present invention, the inorganic infrared ray shielding agent containing tin oxide as a main component is copper oxide, zinc oxide, magnesium oxide, antimony oxide, indium oxide and 4A of the periodic table of the elements. Group 5A or 6A
0.1 or more of one or more components selected from oxides of metal elements belonging to the group, gold, silver and carbon black.
It is characterized in that it is contained in the range of 50 wt%.

Further, in the agricultural sheet of the present invention, the inorganic infrared shielding agent containing tin oxide as a main component has a particle size of 5
It is characterized by being composed of fine powder of less than 00Å. Is the agricultural sheet described in 2.

Further, in the agricultural sheet of the present invention, the infrared shielding layer is a solution or dispersion containing an inorganic infrared shielding agent containing tin oxide as a main component and a transparent resin as a binder. It is characterized in that it is formed by applying it to a material sheet.

Further, the agricultural sheet of the present invention is characterized in that a pollution prevention layer is provided on the surface thereof.

Further, the agricultural sheet of the present invention is characterized in that a fog-proof / drip-free layer is provided on the surface.

Further, the agricultural sheet of the present invention is characterized in that the base material sheet is one of a polyester resin sheet, a vinyl chloride resin sheet and a polyolefin resin sheet.

[0014]

As described above, according to the present invention, the infrared ray shielding layer using the inorganic infrared ray shielding agent containing tin oxide as a main component is provided on the transparent base material sheet, whereby the Infrared rays contained in are blocked, while visible rays and ultraviolet rays are transmitted, so transparency is not impaired. Moreover, since the inorganic infrared shielding agent has high light resistance and heat resistance, an agricultural sheet having a long-lasting shielding effect can be obtained.
In addition, an inorganic infrared shielding agent containing tin oxide as the main component,
Copper oxide, zinc oxide, magnesium oxide, antimony oxide, indium oxide and elements of Periodic Table 4A, 5A
Light resistance and heat resistance by containing one or more components selected from oxides of metal elements belonging to Group 6 or Group 6A, gold, silver and carbon black in the range of 0.1 to 50% by weight. In addition, the infrared ray shielding performance can be optimized according to the intended use without impairing the visible light transmittance and the like. In addition, since the inorganic infrared shielding agent containing tin oxide as the main component is composed of fine powder with a particle size of 500 Å or less, it has excellent dispersibility, transparency, and infrared shielding ability when dispersed in a binder resin. It is possible to obtain an agricultural sheet having different characteristics. Further, the infrared shielding layer is formed by applying a solution or dispersion containing an inorganic infrared shielding agent containing tin oxide as a main component and a transparent resin as a binder to the base sheet. Compared with the case of dispersing in material resin or vapor deposition / sputter film formation on a substrate, special equipment for dispersing powder in high-viscosity molten resin, expensive equipment such as vacuum equipment, etc. A uniform and high-quality infrared shielding layer can be easily formed without the need.

Further, by providing a pollution preventing layer made of a fluororesin, a silicone resin or the like on the surface, an agricultural sheet which is resistant to stain for a long period of time can be obtained.

Further, the surface is formed of a surfactant to prevent dew condensation.
By providing the drip-free layer, even if there is a sudden change in the outside air temperature, it is possible to minimize the formation of dew condensation on the seat surface and the generation of indoor fog.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The configuration of the present invention will be described below in detail. FIG. 1 is a sectional view showing an example of an embodiment of an agricultural sheet of the present invention. Agricultural sheet 10 of the present invention
The basic constitution of (1) is such that the infrared shielding layer 12 using an inorganic infrared shielding agent containing tin oxide as a main component is provided on the transparent base material sheet 11.

The inorganic infrared ray shielding agent used in the present invention is a material having light resistance and contains tin oxide as a main component, and if necessary, copper oxide, zinc oxide, magnesium oxide, antimony oxide, and oxide. 1 selected from indium and oxides of metal elements belonging to the 4A group, 5A group or 6A group of the periodic table of elements, gold, silver and carbon black 1
One kind or two or more kinds of components can be appropriately contained and used in the range of 0.1 to 50% by weight. By forming a mixture containing the above various subcomponents, the infrared shielding layer 1
The spectral transmission characteristics of No. 2 can be changed, and the infrared shielding performance can be optimized according to the intended use without impairing the light resistance, heat resistance, visible light transmittance, and the like.

The inorganic infrared ray-shielding agent containing tin oxide as the main component used in the present invention shows the spectral transmission characteristics of the agricultural sheet 10 of the present invention using fine powder of tin oxide as an example.
As shown in FIG. 3, it has a spectral transmittance characteristic that it sufficiently absorbs and shields near-infrared rays having a wavelength of 700 nm or more, while sufficiently transmitting ultraviolet rays having a wavelength of 300 to 400 nm and visible rays having a wavelength of 400 to 700 nm. doing.
In addition, by adding an appropriate amount of an ultraviolet absorbing substance such as zinc oxide, titanium oxide, or cerium oxide to the above-mentioned inorganic infrared shielding agent containing tin oxide as a main component, it is possible to obtain an appropriate ultraviolet transmittance. Applications such as controlling to a range or blocking only harmful short-wavelength components of ultraviolet rays are possible.

The inorganic infrared ray shielding agent used in the present invention is usually in the form of powder, but fine powder having a particle diameter of 500Å or less is particularly preferable in the present invention. By using such a fine powder having a particle size of 500 Å or less, excellent properties can be obtained in all of the dispersibility, transparency, and infrared shielding ability when dispersed in a binder resin.

As described above, the agricultural sheet 10 of the present invention is obtained by forming the infrared shielding layer 12 using the inorganic infrared shielding agent containing tin oxide as the main component on the transparent base material sheet 11. The infrared shielding layer 12 is formed by coating the base sheet 11 with a coating liquid in which an inorganic infrared shielding agent containing tin oxide as a main component is dissolved or dispersed in a suitable solvent together with a suitable binder resin. Can be formed by. Here, as the binder resin, for example, an acrylic resin, a polyester resin, a polyurethane resin, a polyvinyl resin, a melamine resin, an epoxy resin, a synthetic rubber resin, a fibrin resin, a mixture thereof, or the like, As the solvent, for example, toluene, xylene, methyl ethyl ketone, methyl isobutyl ketone, ethyl acetate, butyl acetate, cyclohexane, ethanol, isopropyl alcohol, or the like, or a mixture thereof, or the like, may be used by appropriately combining any conventionally known materials. You can The amount of the infrared shielding agent containing tin oxide as the main component is not particularly limited, but if the amount is too small, the infrared shielding effect is small, and if it is too large, the coating suitability deteriorates. It is preferable that the range is 5 to 150 parts by weight. The thickness of the infrared shielding layer 12 to be formed is not particularly limited, but is usually in the range of 1 to 10 μm. As a method for forming the infrared shielding layer 12, any known coating means (gravure coating, roll coating, bar coating, air knife coating, etc.) can be arbitrarily applied.

The above-mentioned transparent substrate sheet 1 used in the present invention
As 1, a polyester resin sheet, a vinyl chloride resin sheet, or a polyolefin resin sheet such as polyethylene or polypropylene can be preferably used. Of course, other materials can be used as long as they have transparency.

The pollution prevention layer 13 used in the present invention is made of a material having a small surface tension, such as a fluororesin such as polytetrafluoroethylene or polyvinylidene fluoride, or a silicone resin such as dimethylpolysiloxane or methylphenylpolysiloxane. The outer surface of the agricultural sheet 10, that is, in the case where the infrared shielding layer 12 is provided on the inner side of the base material sheet 11, on the opposite surface of the base material sheet 11, and vice versa. In the case where the infrared shielding layer 12 is provided on the outside, it is formed on the infrared shielding layer 12,
It is possible to obtain an agricultural sheet that prevents a decrease in light transmittance due to the attachment of contaminants such as dust.

The anti-fog / drip-free layer 14 used in the present invention is made of an amphipathic substance having a lipophilic group and a hydrophilic group, such as a cationic surfactant, anionic surfactant, nonionic surfactant, and the like. That is, on the inner surface of the agricultural sheet 10, that is, in the case where the infrared shielding layer 12 is provided on the outer side of the base material sheet 11, on the surface of the base material sheet 11 on the opposite side, and vice versa. In the case where the infrared shielding layer 12 is provided, the agricultural sheet 1 is formed on the infrared shielding layer 12 by forming it.
When water droplets adhere to the inner surface of 0 (condensation), they are quickly diffused on the sheet surface to prevent fogging of the inner surface due to water droplets and suppress re-evaporation of the water droplets to prevent excessive moisture in the room air. It is possible to obtain an agricultural sheet that is promptly removed and prevents the generation of indoor dew.

[0025]

EXAMPLES Examples of the present invention will be described below more specifically. Example 1 A transparent polyester resin sheet having a thickness of 50 μm is used as the substrate sheet 11, and one side of the polyester resin sheet is coated with a coating solution having the following composition by a gravure coating method and dried to have a thickness of 3 μm. The infrared shielding layer 12 was formed.

Composition of coating liquid: Tin oxide (particle size: 50 to 100Å) 25 parts by weight Acrylic resin (trade name: Dynar, manufactured by Mitsubishi Rayon Co., Ltd.) 25 parts by weight Solvent (toluene) 50 parts by weight

Infrared shielding layer 1 formed as described above
A polytetrafluoroethylene resin layer was further applied onto 2 by a gravure coating method to a thickness of 1 μm to form a pollution prevention layer 13. Further, a nonionic surfactant having a thickness of 1 μm is applied to the other surface of the polyester resin sheet which is the base material sheet 11 by a gravure coating method to form a fog-proof / drip-free layer 14 for agricultural use of the present invention. Sheet 10 was prepared.

Although the infrared shielding layer 12 is formed between the base sheet 11 and the pollution prevention layer 13 in this embodiment, it is provided between the base sheet 11 and the fog-proof / drip-free layer 14. The order of the layer constitution is not particularly specified. Moreover, although the polyester resin sheet was used as the base material sheet 11, a vinyl chloride resin sheet or a polyolefin resin sheet may be used depending on the application.

When the spectral transmission characteristics of the above-mentioned agricultural sheet of the present invention were measured, as shown in FIG.
It was confirmed that 0 nm ultraviolet light and visible light having a wavelength of 400 to 700 nm are transmitted, infrared light having a wavelength of 700 to 3000 nm is sufficiently shielded, and particularly infrared light having a wavelength of 1800 nm or more is almost completely shielded.

Next, a heat insulation test was carried out using the agricultural sheet of the present invention. The test method is as follows: a thermometer is installed in the center of the bottom of a styrofoam insulation box with a black interior surface of 200 mm in height, width, and height of 5 mm with an open top, and the top is open. The section was sealed with an agricultural sheet, left standing on the rooftop of a building in Tokyo from 9 am to 3 pm, and the temperature change during that period was observed.
The time was July 1995, and the weather was fine. As a comparative example, the same heat insulation test was performed using the same polyester resin sheet as the base sheet of the agricultural sheet of the above-mentioned example.

As shown in FIG. 3, the result of the adiabatic heat sink is as follows.
It was confirmed that when the agricultural sheet of the present invention was used, the temperature rise inside the heat insulating box was suppressed to about two-thirds as compared with the case of using the sheet of the comparative example. In the above comparative experiment, since the inside of the heat insulating box was not ventilated at all, even when the agricultural sheet of the present invention was used, a temperature higher than the outside temperature was observed. It has been found that visible rays can be sufficiently transmitted while infrared rays can be blocked to prevent the temperature rise remarkably.

[0032]

As described above, according to the present invention, by providing an infrared shielding layer using an inorganic infrared shielding agent containing tin oxide as a main component on a transparent substrate sheet, it is possible to prevent sunlight from seeing. It does not interfere with the growth of crops because it fully transmits the ultraviolet rays and visible rays contained in it, and by absorbing and blocking infrared rays, it prevents excessive temperature rises in indoor areas such as greenhouses in summer, especially in warm regions. However, it can be suitably used for cultivating crops susceptible to high temperatures.

The agricultural sheet of the present invention has a remarkably high light resistance as compared with conventionally known organic type infrared ray shielding agents such as amino compounds, and thus has an advantage that the infrared ray shielding effect lasts for a long time. . In comparison with inorganic infrared shielding agents, for example, when compared with those using calcium carbonate, silicate, aluminum hydroxide, etc., the wavelength is 3 μm.
Since it also effectively shields near-infrared rays of m or less, it is effective in suppressing an increase in indoor temperature in summer. In addition, compared with the one using zinc oxide powder doped with aluminum, silicon, titanium or the like, since it sufficiently transmits ultraviolet rays having a wavelength of 300 to 400 nm, colored crops such as aubergines and flowers that require ultraviolet rays for growth are used. It has an excellent advantage that it can be effectively applied to cultivation of species and pollination using insects such as bees that detect ultraviolet rays.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a configuration example of an agricultural sheet of the present invention.

FIG. 2 is a graph showing the spectral transmission characteristics of the agricultural sheet of the present invention.

FIG. 3 is a graph showing the heat insulating effect of the agricultural sheet of the present invention.

[Explanation of symbols]

 10: Agricultural sheet 11: Base sheet 12: Infrared shielding layer 13: Contamination prevention layer 14: Fog-proof / drip-free layer

Claims (7)

[Claims] 1. An agricultural sheet comprising a transparent base material sheet and an infrared shielding layer containing an inorganic infrared shielding agent containing tin oxide as a main component. 2. The inorganic infrared ray shielding agent containing tin oxide as a main component is copper oxide, zinc oxide, magnesium oxide, antimony oxide, indium oxide and 4A of the periodic table of elements.
Oxides of metal elements belonging to group 5A or 6A,
The agricultural sheet according to claim 1, which contains 0.1 to 50% by weight of one or more components selected from gold, silver and carbon black. 3. The agricultural sheet according to claim 1, wherein the inorganic infrared ray shielding agent containing tin oxide as a main component is made of fine powder having a particle size of 500 Å or less. 4. The infrared shielding layer is formed by applying a solution or dispersion containing the inorganic infrared shielding agent containing tin oxide as a main component and a transparent resin as a binder to the base sheet. The agricultural sheet according to claim 1, 2 or 3, wherein 5. The agricultural sheet according to claim 1, wherein the surface of the agricultural sheet is provided with a pollution prevention layer. 6. The agricultural sheet according to claim 1, wherein the surface is provided with an anti-fog / drip-free layer. 7. The substrate sheet is any one of a polyester resin sheet, a vinyl chloride resin sheet, and a polyolefin resin sheet.
The agricultural sheet according to 4, 5, or 6.