JPH10248406A - Sheet for greenhouse - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a sheet for a greenhouse capable of preventing wind, improving heat insulation performance and adjusting light shielding rate performance without passing through water. SOLUTION: For an outer spread sheet 1, belt-like bodies 12 are thermally melt-stuck to a water non-transmissive and light transmissive synthetic resin film 11. The belt-like bodies are non-woven fabric for which the long fiber filaments of synthetic resin are joined in high density, the reflectance of light is more than 90% and the absorptance of the light is less than 1%. Thus, the heat insulation performance is improved and the light shielding rate performance is adjusted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a so-called greenhouse sheet which is used for covering greenhouses such as aluminum pipes for lining or lining in greenhouse cultivation related to agriculture and horticulture. .

[0002]

2. Description of the Related Art Greenhouse H for agriculture or horticulture
As shown in FIG. 1, a frame is constituted by the pillars 4 and the beams 5 which are planted, and a sheet is stretched on the side surface and the entire surface of the ceiling (roof). The inner lining sheet (curtain) 2 has a double-layered structure in which a predetermined gap is provided inside the outer lining sheet 1 so as to be able to expand or contract. Since it is necessary to control the temperature and the amount of solar radiation optimal for growing the plants grown in the greenhouse, the temperature inside the greenhouse H can be reduced by stretching the lining sheet 2 or adjusting the stretching range. It is to adjust.

[0003] Conventionally, as sheets for lining greenhouses, various properties such as water impermeability, light transmission, heat retention, toughness, durability, and weather resistance have been required. , Ethylene-vinyl acetate copolymers, polyester-based films and the like. Originally, in this kind of cultivation method, the purpose of promoting cultivation and early cultivation of agricultural products, etc., and in order to save heating energy for that purpose, heat insulation was regarded as the most important. Vinyl chloride films are frequently used. However, polyvinyl chloride film is excellent in heat retention, but it contains plasticizer in the resin, so it migrates to the film surface during use and sticks, and the light transmittance is impaired by absorbing dust. It is a problem. Polyethylene-based films are chemically stable without plasticizers and have excellent weather resistance.However, they are easily charged and cause a decrease in light transmittance due to dust absorption, and also have a serious disadvantage of poor heat retention. There is. Ethylene-vinyl acetate copolymer films are also improved in heat retention, but are not as good as polyvinyl chloride films. Polyester-based films have good optical properties, but have difficulty in light resistance.

In order to solve these problems, for example, a film made of a composition obtained by blending a magnesium silicate and aluminum hydroxide in a soft polyvinyl chloride resin (Japanese Patent Publication No. 62-10124), a transparent vinyl chloride Films formed by blending resin with inorganic fine powders such as lithium and calcium (Japanese Patent Publication No. 62-41247), and films using a composition comprising a polyethylene resin and a modified polyvinyl alcohol resin (Japanese Patent Publication No. 62-27099) JP-A-63-20260), a film using a composition comprising a polyethylene resin and a low saponified polyvinyl acetate (Japanese Patent Publication No. 63-20260), and a film having a low refractive index laminated on the surface of a polyester film (Japanese Patent Publication No. No. 1-30445) and polyester-based multilayer films containing specific organic compounds (Japanese Utility Model Publication No. 3-18182). The warmth of the improvement has been the biggest concern.

However, given the recent diversification of cultivated crops, the purpose of greenhouses is to maintain sufficient solar radiation inside while maintaining the necessary heat retention during the low temperature season.
In the high temperature period, an excessive rise in temperature can be controlled, that is, it is necessary to mitigate a rapid change in the temperature inside the house due to a change in the outside air temperature. For this purpose, covering or stretching a woven or knitted fabric or a non-woven fabric, etc., containing black flat yarn or aluminum-deposited flat yarn, as the outer sheet of the green house outer sheet or as the inner sheet of the green house. Has also been done.

[0006] Recently, there has been an attempt to use a nonwoven fabric (for example, "Tyvek" (registered trademark) manufactured by DuPont) having a light blocking ratio (reflectance of light) of 90% or more manufactured by a flash spinning method. Tyvek sheets are waterproof and are excellent as light-blocking materials, and therefore have high heat-insulating performance, but cannot change the light-blocking rate according to the type of plant to be cultivated. Therefore, the light-shielding rate is often too strong for many plants, and it is difficult to use it for both exterior and interior linings. In view of this, there have been proposed sheets obtained by cutting Tyvek into a tape shape and plain-weaving, Russell-weaving, and leno weaving.

[0007]

However, although both of them have excellent light-shielding and heat-shielding effects, they are not suitable for external lining because of the drawback that they are water-permeable because of the net ground and have poor heat insulation performance because of their poor heat-retaining ability. is there.

Accordingly, an object of the present invention is to provide a greenhouse sheet that is impermeable to water, prevents wind, has high heat retention performance, and can adjust the light blocking rate performance.

[0009]

SUMMARY OF THE INVENTION In order to solve the above problems, a first feature of the present invention is that a strip 12 is provided on a non-water-permeable and light-transmitting synthetic resin film 11 at a predetermined interval. It is provided, wherein the material of the band-shaped body is a non-woven fabric in which synthetic resin long fiber filaments are bonded at a high density,
The gist is that the light reflectance is 90% or more and the light absorption is 1% or less.

A second feature of the present invention is that a resin laminate layer 21 is formed on at least one surface of the strip, and the strip and the synthetic resin film 11 are heat-sealed with the resin laminate layer as an abutting surface. The point is that they are integrated.

Further, a third feature of the present invention is that the strip is made of high-density polyethylene, and the resin laminate layer and the synthetic resin film are made of polyethylene or an ethylene / α-olefin copolymer. I do.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described with reference to the drawings.
As shown in FIG. 1, the ceiling (roof) has a double structure including an outer sheet 1 and an inner sheet 2, and is supported and stretched by frames such as columns 4 and beams 5. Exterior sheet 1
And the lining sheet 2 are made of the same material and have the same configuration.

The outer sheet (hereinafter referred to as “sheet”) 1 will be specifically described with reference to FIGS. 2, 3 and 4. The belts 12 are provided at predetermined intervals by means of heat welding.

Here, the material of the synthetic resin film 11 can be selected from resins conventionally used for the base of the sheet for covering. For example, polyvinyl chloride, polyvinylidene chloride, polypropylene, polyethylene, polystyrene, polyethylene terephthalate, and films such as polymethyl methacrylate,
In consideration of the chemical stability and the ease of disposal, and the balance between the heat-fusibility with the band-shaped film described below and its workability, polyethylene or ethylene / α-olefin copolymer is particularly preferably used. . In particular,
High density polyethylene, low density polyethylene, linear low density polyethylene, ethylene-polypropylene copolymer,
Ethylene-butene copolymer, ethylene-4-methyl-1
-Pentene copolymer, ethylene-vinyl acetate copolymer,
Examples thereof include an ethylene-acrylic acid copolymer, and these synthetic resins can be used as a mixture or as a multilayer structure.

Further, as long as the light transmittance of the film itself is not significantly impaired, glass fine particles, titanium oxide, aluminum hydroxide,
Fillers such as magnesium carbonate, calcium carbonate, silicon oxide, zeolite, and talc are added.Furthermore, UV absorbers and light stabilizers such as hydroquinone-based, salicylic acid-based, and benzophenone-based additives for improving weather resistance, and anti-fog properties Antifogging agents such as glycetin fatty acid ester and sorbitan fatty acid ester for improvement, and antiblocking agent, antioxidant, heat stabilizer, lubricant, etc. You can also.

Next, the nonwoven fabric forming the belt-shaped body 12 is called a long-fiber nonwoven fabric, and long fibers are randomly deposited and bonded by a direct spinning method in which spinning, drawing, opening, and bonding steps are continuously performed. Specifically, a spun thermoplastic synthetic resin is put into an extruder to make it into a molten state, and a fiber extruded from a spinning nozzle is formed into a drawn fiber by a roller method or an air jet method. Spinning nonwoven fabric by the bond method, nonwoven fabric by the melt blow method in which a molten resin is jetted from a spinning nozzle together with a high-pressure gas flow into a drawn fiber, or a solution in which a spinnable thermoplastic synthetic resin is dissolved in a solvent under high temperature and high pressure Non-woven fabrics made by flash spinning, which emits into the atmosphere through a nozzle and evaporates the solvent to produce fibers, can be used. Nonwoven is especially preferred by flash-spinning a good point.

In the flash spinning method, a solution obtained by dissolving a synthetic resin such as high-density polyethylene or polypropylene in a solvent having a low boiling point such as a halogenated hydrocarbon, an aromatic hydrocarbon, or an aliphatic hydrocarbon under high temperature and high pressure is used. Because it is released into the atmosphere at low temperature and low pressure through a spinning nozzle provided with a pressure drop chamber in a more pressurized state, and the solvent evaporates instantaneously, the orientation is given to the fiber by its expansion force. Ultra-fine and high-strength fibers with a single-fiber fineness of about 0.1 to 0.3 dr are formed, and the non-woven fabric obtained by depositing and thermo-compressing these fibers while crossing each other has a dense structure bonded at high density. It is opaque and has a high degree of whitening, and has a spectral characteristic with respect to light suitable as a component of the sheet of the present invention.

As a non-woven fabric by flash spinning, specifically, "Tyvek" (registered trademark) manufactured by DuPont)
The nonwoven fabric has excellent characteristics such as a light reflectance of 90% or more and a light energy absorption of 1% or less. For example, Tyvek 1422A
Has a reflectivity of 91.30% and an absorptivity of light energy of 0.1.
It is 83% and the light transmittance is 7.87%, which is excellent in characteristics that the light reflectance is high and the light absorptivity is low. The numerical values indicate the average values of the reflectance at all wavelengths of light, etc., and are based on experiments at the Flowering Control Laboratory of the Vegetable and Tea Research Institute of the Ministry of Agriculture, Forestry and Fisheries.

These nonwoven fabrics are made of grooved rolls or 2
Between the guide rolls of the book, the strip-shaped body 12 is slit into a large number of books according to a predetermined width by a cutter blade or a round blade.
Becomes The width of the slit is preferably 5 to 35 mm, more preferably 10 to 20 mm, from the viewpoint of practicality and handling.

The slit strips 12 are arranged at predetermined intervals on the surface of the non-water-permeable and light-transmitting synthetic resin film 11 and are adhered to each other. A distance of 50 to 200% of the width is preferred. That is, if the arrangement interval is narrower than this ratio, the coverage of the band-shaped body 12 with respect to the synthetic resin film 11 tends to be too large, so that a sufficient amount of solar radiation tends not to be secured. On the other hand, if the arrangement interval is wider than this ratio. The area occupied by the band-shaped body 12 in the sheet surface is too small, and the effect due to the spectral characteristics of the nonwoven fabric is not exhibited. However, this strip 12
It is not necessary that all of the arrangement intervals be constant, and it works as long as the coverage of the band-shaped body 12 per a predetermined area is about 30 to 70%. Just set it.

In the method of bonding the belt 12 and the synthetic resin film 11, the belt 12 can be arranged as it is and thermocompression-bonded with a heating roll. However, in order to adhere firmly, the belt 12 is coated with an adhesive. There is also a method of bonding by interposing a hot melt. However, as a method capable of processing stably at high speed and obtaining a strong adhesive force, a laminating layer 21 in which a resin composition of the same type or similar to that of the synthetic resin film 11 is thinly coated on at least one surface of the strip 12 is used. After arranging the strips 12 as a surface where the laminate layer 21 is in contact with the synthetic resin film 11, the most common method is to perform heat fusion by various fusion methods such as a hot oven type, a hot roll type, and a hot plate type. preferable. In the case of heat fusion using the laminate layer 21, the laminate layer 21 is usually formed in a state of a wide non-woven fabric, and then slit into a predetermined width to be used as the belt-shaped body 12.

Further, as described above, from the viewpoints of workability and adhesive strength due to thermal fusion of each component, and that no toxic gas is generated in the combustion process in disposal, as described above. It is preferable that the belt 12 is made of a polyolefin-based resin, and the laminate layer 21 and the synthetic resin film 11 are made of polyethylene or an ethylene / α-olefin copolymer.

[0023]

[Example] "Tyvek" manufactured as a nonwoven fabric by fiberizing high-density polyethylene by flash spinning.
L1000AG (Dupont) was selected. The spectral characteristics of the nonwoven fabric were measured at an average value of the effective light emission range of 400 to 700 nm by a wavelength-specific optical energy analyzer equipped with an integrating sphere. The reflectance was 92%, the absorption rate of light energy was 0.8%,
The light transmittance was 7.2%.

On one side of this non-woven fabric, a 20 μm-thick laminated layer 21 was formed by extrusion lamination using low-density polyethylene (MFR = 8.0 g / 10 min.), And then a 15 mm width was placed between two guide rolls. And passed through a slitter in which a cassette having a distance piece of cutter blade was installed, and wound up as a strip 12 having a width of 15 mm.

Next, as the synthetic resin film 11, an ethylene-vinyl acetate copolymer (MFR = 5.0 g / 10 min., VA content 10%)
A film having a thickness of 50 μm was selected from the above and passed through the heating rolls in a state where the strips 12 were arranged in parallel in the longitudinal direction at 10 mm intervals so that the laminate layer 21 was in contact with the surface. To form a green house sheet of this example.

Table 1 summarizes the physical property values of the green house sheet of this embodiment. The measurement was performed in accordance with JIS-L1096.

[0027]

[Table 1]

[0028]

According to the first aspect of the present invention, when used as an outer sheet of a green house, it is impermeable to water, prevents wind, has high heat insulation performance, and has a width and an arrangement interval of a band. Can be adjusted by selecting and applying the one that has the optimal light-shielding rate for the plant that cultivates it, and if it is used as a lining sheet, cultivate it in the daytime It can be adjusted to the optimal amount of shading for plants, and exhibits heat insulation performance at night. Further, according to the second aspect of the invention, stable processing can be performed at a high speed and a strong adhesive force can be obtained. Further, according to the third aspect of the invention, as a whole sheet, the heat of each constituent member is reduced. There is no toxic gas generated in the combustion process during disposal due to the workability and adhesion strength due to fusion.

[Brief description of the drawings]

FIG. 1 is a perspective view of a green house.

FIG. 2 is a front view of a seat.

FIG. 3 is an enlarged sectional view taken along line aa of FIG. 2;

FIG. 4 is an enlarged cross-sectional view taken along line aa of FIG. 2 corresponding to the sheet of the present embodiment.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 House sheet 11 Synthetic resin film 12 Belt 21 Laminate layer

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI B65D 65/16 B65D 65/16

Claims (3)

[Claims] 1. A non-water-permeable and light-transmitting synthetic resin film in which strips are provided at predetermined intervals, wherein the strip is made of synthetic resin long fiber filaments bonded at high density. A greenhouse sheet, wherein the nonwoven fabric has a light reflectance of 90% or more and a light absorption of 1% or less. 2. A resin laminate layer is formed on at least one surface of the band, and the band and the synthetic resin film are heat-sealed and integrated with the resin laminate layer as an abutting surface. The green house sheet according to 1. 3. The greenhouse sheet according to claim 2, wherein the strip is made of a polyolefin resin, and the resin laminate layer and the synthetic resin film are made of polyethylene or an ethylene / α-olefin copolymer.