JPH11235129A - Light-shielding material for agriculture and horticulture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a light-shielding material suitable for a short day treatment culture of flowering plants and for a blanching culture of vegetables, having an approximately perfect light-shielding property against solar light, having easy handleability due to a large strength and a proper flexibility and capable of improving the inner environment of a covered culture house, etc., so that the inner temperature of the covered culture house, etc., do not excessively not rise. SOLUTION: This light-shielding material for agriculture and horticulture is obtained by forming as a basic structure a laminate comprising a white non-woven fabric 2 prepared by accumulating and adhering synthetic resin long filaments in a high density as a surface layer and a carbon black-containing black resin layer 3, preferably a black resin layer having a multi-layered structure, as a back surface and, if necessary, further integrally laminating a reinforcing material 4 and a protecting layer 5 to the laminate as the basic structure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light-shielding material for agriculture and horticulture, and is required to have almost complete light-shielding in short-day processing cultivation of flowers and soft-white cultivation of vegetables. The present invention relates to a shading material for agricultural and horticultural use used in a cultivation method.

[0002]

2. Description of the Related Art Conventionally, as a covering material for shading for agriculture and horticulture, a coarse net-like material such as a cold gauze or a woven fabric made of a monofilament or a flat yarn is often used. In this method, a suitable amount of light can be taken from the openings of the net-like object while simultaneously blocking the direct sunlight to an appropriate amount of light, so that tea plants, soft agricultural crops, shiitake mushrooms, fruit trees, and flowers that require temperature control are required. It is used for the purpose of preventing overheating and drying in the high-temperature period. However, since it is a net-like material, there is also a limit in increasing the light-shielding rate, and it is usually used in a cultivation method in which the effect of suppressing the transmission of sunlight to some extent in the range of 60 to 90% can be expected.
Therefore, it is considered unsuitable as a light-shielding material used in short-day treatment cultivation of flowers such as chrysanthemums and the like, which require almost complete solar shading, and soft cultivation of vegetables.

[0003] In short-day treatment cultivation of flowers, a method of arranging light-shielding materials inside or outside a cultivation house and adjusting the daylight hours to control flowering enables long-term continuous flowering and same-year cultivation. I do. In soft-white cultivation of vegetables, green onions, asparagus, independence, yellow chive, bean sprouts and the like are grown in a tunnel made of a light-shielding material, or a part such as a stem is concealed by a light-shielding material to soften.

[0004] As the light-shielding material used therefor, there is a polyvinyl chloride or polyethylene film colored with a black pigment. However, if a high light-shielding rate is required for the film, the thickness is required to be 100 μm or more, so the weight is bulky, and the film is long and wide because it is easily stretched.
Insufficient strength and poor handling properties.In addition, the film itself becomes hot due to the high light absorption of the material, and the heat released from it increases the temperature inside the house, causing flowers and vegetables to suffer from high-temperature damage. It is a problem in the tendency. Some films are colored with a silver-based pigment such as aluminum powder to increase light reflectance, but no remarkable effect is found in suppressing light absorption.

In view of the above, it is difficult to absorb sunlight and to improve the dimensional stability as a sheet body. A polyester film is used as a base material, and one surface thereof is white and the other surface is a black polyvinyl chloride resin film. (Japanese Unexamined Patent Publication No. 9-234829) has been proposed, but it is assumed that the physical strength is insufficient and a problem of toxic gas generation during incineration is assumed. In addition, a proposal to use nonwoven fabrics made by spunbonding, meltblown, or flash spinning as light-blocking materials
(JP-A-5-304836, JP-A-9-683337, etc.). This is to make the air permeability of the nonwoven fabric effective, but this is not as important a requirement in this type of light-shielding material. Rather, the basis weight 50 shown in the examples
If it is ~70g / m ² about nonwoven, partially large deposit spots of the fibers also exhibit high shading rate is sufficient light-shielding property is obtained in the whole when stretched in a large facility such as cultivation house It is not at present.

[0006]

DISCLOSURE OF THE INVENTION The present invention is suitable for short-day processing cultivation of flowers and soft-white cultivation of vegetables, and is capable of almost complete shading. It is an object of the present invention to provide a light-shielding material that can improve the environment so as not to be affected.

[0007]

SUMMARY OF THE INVENTION The present invention relates to an agricultural apparatus comprising a white nonwoven fabric having synthetic resin long fiber filaments deposited and bonded at a high density on its surface and a black resin layer containing carbon black on its rear surface. It is a shading material for gardening.

Further, the above-mentioned laminate is reinforced with a reinforcing material,
Alternatively, a laminated structure having a protective layer formed thereon is preferable, and as a suitable material, the nonwoven fabric has a basis weight of 30 to 100 g / m ² , and the black resin layer has a thickness of 30 to 30% in which carbon black is blended by 2 to 20% by weight. An agricultural and horticultural light-shielding material having a thickness of 100 μm, more preferably an agricultural and horticultural light-shielding material having a black resin layer having a multilayer structure.

[0009]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a sectional view of a light-shielding material according to the present invention, and the structure thereof will be described in detail below. 1 and 2 show a laminate of the nonwoven fabric 2 / black resin layer 3 as a basic structure of the present invention. FIG. 1 is a schematic cross-sectional view, and FIG. 2 is a partially broken schematic plan view.

[0010] The nonwoven fabric 2 constituting the light-shielding material of the present invention comprises:
It must be made of long fibers made of synthetic resin. This is because the light-shielding material is often used outdoors for a relatively long period of time, and because it is a synthetic resin, it does not corrode and is durable. Is preferably employed because of its excellent resistance. The basis weight of the nonwoven fabric 2 is preferably from 30 to 100 g / m ^2, the mechanical strength is significantly reduced to be less than a basis weight of 30 g / m ^2, to be unsuitable due to the large partial intensity difference, whereas, exceeds a basis weight 100 g / m ² when the weight is also located less flexible,
It is considered unsuitable, including handling, as it will interfere with the expansion work.

Such a nonwoven fabric 2 is formed by spinning, drawing, opening,
It is obtained by directly depositing and bonding long fibers by a direct spinning method in which the bonding process is continuously performed.Specifically, a spinnable thermoplastic synthetic resin is put into an extruder to be in a molten state. A nonwoven fabric by a spun bond method in which fibers extruded from a spinning nozzle are drawn into fibers by a roller method or an air jet method, or a melt blown in which a resin in a molten state is jetted from a spinning nozzle together with a high-pressure gas flow to form drawn fibers. Non-woven fabric by the spinning method, and a non-woven fabric by the flash spinning method in which a solution in which a spinnable thermoplastic synthetic resin is dissolved in a solvent under high temperature and high pressure is discharged into the atmosphere through a spinning nozzle, and the solvent is vaporized into a fiber. A non-woven fabric formed by flash spinning is particularly suitable in that it is excellent in water pressure resistance and moisture permeability.

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. It is released into the atmosphere at low temperature and low pressure through a spinning nozzle equipped with a pressure drop chamber in a more pressurized state, and the solvent evaporates instantaneously, giving the fiber orientation by its expansion force. An ultra-fine, high-strength fiber with a single-fiber fineness of about 0.1 to 0.3 dr is 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 has excellent mechanical strength.

The nonwoven fabric 2 is made of long fibers deposited and bonded at a high density, so that it is opaque and has a high degree of whitening. However, the material constituting the light-shielding material surface has the following spectral characteristics with respect to light. Those satisfying the numerical values shown in are preferred. -Light reflectance 90 to 95%-Light absorption 1 to 0%-Light transmittance 9 to 5%

That is, in the nonwoven fabric 2, the light reflectance is 90%.
Higher than above, effectively reflects sunlight and has a light absorption of 1
% Or less, the nonwoven fabric itself is less likely to accumulate heat, and a rise in the temperature inside the coated nonwoven fabric can be suppressed.
Then, since the light transmittance of the nonwoven fabric alone is about 10%, the black resin layer is laminated on the back surface to provide almost perfect light shielding performance.

The black resin layer 3 is a film formed by selecting carbon black as a pigment having high concealing power, low cost, and good workability such as dispersibility, and blending it with a resin raw material. The resin used is not particularly limited as long as it can form a film, and examples thereof include a polyolefin resin, a polyester resin, a polyamide resin, and a polyvinyl alcohol resin. Carbon black is used in ordinary resin molding, and does not need to have special specifications.

Here, since the black resin layer 3 is for imparting complete light-shielding properties, which is difficult only with a nonwoven fabric, it is naturally necessary to suppress light transmission as a resin layer. Factors for this include the blending amount of carbon black and the thickness of the resin layer. When examined only for the purpose of shading, the effect can be expected as the content of carbon black increases and the thickness of the resin increases. However, if it is considered inexpensively and feasible without affecting the productivity, carbon black is blended in the range of 2 to 20% by weight with respect to the resin, and the thickness of the resin layer is 30 to 30% by weight. Suitably, it is 100 μm. That is, if the carbon black content is less than 2% by weight, a sufficient light-shielding effect cannot be obtained even if the resin thickness increases, and if it exceeds 20% by weight, the dispersibility deteriorates and the production efficiency decreases. There is a tendency for quality to deteriorate, such as possible. Regarding the thickness of the resin layer, if it is less than 30 μm, there is a limit to light shielding even if a large amount of pigment is blended, and if it exceeds 100 μm, the laminate with the nonwoven fabric is inferior in flexibility and increases in weight and hinders handleability. This is disadvantageous in terms of cost.

Examples of a method for laminating the black resin layer 3 on the nonwoven fabric include an extrusion lamination method and a film bonding method.
Extrusion lamination is a method in which a resin and carbon black are charged into an extruder cylinder, extruded from a T-die in a molten state onto the surface of a nonwoven fabric, and cooled to directly laminate a black resin layer. The film bonding method is a method in which a black film formed in advance is prepared, and the formed film is bonded to a nonwoven fabric with an adhesive or the like. Molded film is
The processing method can be appropriately selected in accordance with the material, such as using an unstretched film if flexibility as a laminate is required, or a uniaxial or biaxially stretched film if enhancement of strength is desired.

Here, the black resin layer 3 preferably has a multilayer structure. FIG. 3 shows a laminated state having a two-layer structure including a first black resin layer 31 and a second black resin layer 32. This is because in an extrusion lamination method that is effective in that stable production at high speed is possible, if the mating substrate is a fibrous nonwoven fabric, resin unevenness due to unevenness or thickness of the nonwoven fabric, Since it is supposed that pinholes occur due to fluff or resin thickness unevenness occurs in the laminating width direction, it is preferable to perform two laminating steps. It is also an effective means to prepare a nonwoven fabric and a pre-formed black film in the same manner, and laminate these two members with a black sand resin. The black resin layers 31 and 32 having a multilayer structure formed by these methods preferably have a total thickness of the resin layers within the above-described range.

As described above, the light-shielding material of the present invention is basically composed of the white nonwoven fabric 2 and the black resin layer 3,
For example, laminating the reinforcing member 4 to further increase the strength is an effective configuration for improving the physical properties as a durable material used for a relatively long period of time. in this case,
The reinforcing material 4 is interposed between the nonwoven fabric 2 and the black resin layer 3 to be integrated (FIG. 4-a), or is laminated on the black resin layer 3 on the back side in actual use (FIG. 4-b). Become.

Here, the reinforcing member 4 is used to improve mechanical properties such as tensile strength and tear strength and to make it durable and easy to handle. A typical example is a lattice-like mesh body formed as follows.

The synthetic resin yarn constituting the reinforcing material 4 preferably has a fineness of 100 to 10,000 dr. That is, if the fineness is less than 100 dr, the reinforcing effect is insufficient due to insufficient strength and the high fineness side There is no particular limitation on the material having extremely high strength, but a fineness of 10,000 dr is generally the upper limit in terms of strength and flexibility required for a light-shielding material or appearance. Further, the grid spacing is appropriately selected depending on the degree of reinforcement.

When laminating the reinforcing material 4, as shown in FIG. 4-a, a white nonwoven fabric / a reinforcing material / a black resin layer, or as shown in FIG.
As shown in -b, the white nonwoven fabric / black resin layer / reinforcing material is superimposed in the order of lamination, or is partially adhered with an adhesive at each lamination stage, or is previously dissolved in a solvent on the surface of the reinforcing material 4 It is possible to bond by various methods such as coating the agent, drying and heat bonding, but the most preferable bonding method is to heat seal the surface of the reinforcing member 4 with a low melting point polymer. It is.

For example, a high-melting-point polymer yarn, in which at least a low-melting-point polymer is present on a part of the surface, is arranged in a lamination type or a core-sheath type in a net-like manner. The reinforcing material becomes firmly bonded and integrated as a laminate by heat compression. Specifically, the multilayer film formed by extruding from a multilayer die in a molten state with a high-melting polymer as a core layer and a low-melting polymer as both outer layers as a low-melting polymer, and shredding the film is several times larger. A multi-layered flat yarn obtained by heating and stretching, or a composite filament cooled by extruding from a nozzle in a molten state with a high melting point polymer positioned in a core layer and a low melting point polymer positioned in a sheath layer, and then cooled. These filaments are arranged and intersected in a course using a loom or the like to form a lattice-like mesh body.

In a laminate having a white nonwoven fabric 2 and a black resin layer 3 as a basic structure, a transparent layer having a high light transmittance so as not to lower the reflectance due to the high whiteness while increasing the wear resistance of the exposed nonwoven fabric surface. By the idea of protecting with
Specifically, as shown in FIG. 5, it is effective to form a transparent film protective layer 5 having a thickness of 10 to 50 μm. As the protective layer 5, in addition to the transparency as a film,
It is desirable that the non-woven fabric 2 can be heat-sealed, and is selected from a polyolefin resin, a polyester resin, a polyamide resin, and a polyvinyl alcohol resin.

Further, when a method of spreading the light-shielding material inside the cultivation house is assumed, it is effective to impart a drip property in order to prevent water droplets from adhering. The treatment is performed by mixing a predetermined amount in the resin layer, or applying a solution containing a surfactant to the black resin layer and drying. When the reinforcing material is present on the outermost surface, a solution containing a surfactant is applied from the surface of the reinforcing material. As the surfactant, any of a nonionic surfactant, an anionic surfactant, a cationic surfactant, an amphoteric surfactant and the like can be used.

As the nonionic surfactant, any of a polyhydric alcohol surfactant and a polyethylene glycol surfactant can be used. Among them, sorbitan monofatty acid ester sorbitan laurate, sorbitan palmitate, and stearin Sorbitan acid ester, sorbitan oleate, or monoglyceride stearate of fatty acid monoglyceride,
Oleic acid monoglyceride and the like can be mentioned. Examples of the anionic surfactant include sodium polyoxyethylene lauryl ether sulfate as a sulfate salt, sodium alkylnaphthalene sulfonate as a sulfonate, and potassium potassium alkylphosphate as a phosphate salt. As the cationic surfactant, a primary amine salt,
Secondary amine salts, tertiary amine salts, quaternary ammonium salts and the like can be mentioned, and examples of the amphoteric surfactants include amino acid type amphoteric surfactants and betaine type amphoteric surfactants.

The use of the light-shielding material of the present invention thus obtained is intended to effectively reflect sunlight, further reduce light absorption, and suppress the material itself from storing heat.
The white non-woven fabric is placed on the front side and the black resin layer is placed on the back side.

[0028]

EXAMPLES Hereinafter, specific examples of the light-shielding material of the present invention will be exemplified as examples, and evaluations thereof will be summarized. The test method is as follows.

Test methods 1. Tensile test: JIS-L1096 compliant 2. Tear test: JIS-L1096 compliant 3. Light-shielding test: Using a photocell illuminometer TOPCON, IM-3, when the illuminometer is 10,000 Lux when no sample is used , And then the sample was set, and the light-shielding ratio was measured (by the Japan Chemical Fiber Inspection Association).

Example 1 As a nonwoven fabric, Tyvek 700AG (basis weight 41 g / m ² ) manufactured by Dupont and manufactured by fiberizing high-density polyethylene by flash spinning was selected. Next, as a thermoplastic resin, linear low-density polyethylene (density = 0.924 g / cm
³ , MFR = 10.0 g / 10 min.) A resin composition comprising 95% by weight, 4% by weight of carbon black as a pigment, and 1% by weight of sorbitan stearate as a nonionic surfactant was charged into an extruder. A black resin layer having a thickness of 50 μm was laminated on the surface of the nonwoven fabric by a melt extrusion lamination method to obtain a light-shielding material of Example 1 (see FIG. 1).

Example 2 Using the same nonwoven fabric and resin composition as in Example 1, a black resin layer was formed by a multi-layer laminating step to form a first layer having a thickness of 20 μm.
Thickness, the thickness of the second layer was set to 30 μm, and multiple black resin layers were laminated to obtain a light-shielding material of Example 2 (see FIG. 3).

Example 3 A high-density polyethylene (density = 0.
956 g / cm ³ , MFR = 1.0 g / 10 min.) As a core layer, and low-density polyethylene (density = 0.924 g / cm ³ , MFR = 3.0
g / 10min.) as an outer layer, a multilayer film having a three-layer structure is produced by co-extrusion inflation molding method, cut into a tape shape, and stretched by a hot plate contact stretching method. It was stretched and oriented to 5.2 times and subjected to an annealing treatment to form a three-layer flat yarn having a fineness of 350 dr. This flat yarn was used as a weft, formed into a lattice with a spacing of about 8 mm, and pressed with a heated metal roll to heat-bond the intersection of the weft as a reinforcing material. Next, the reinforcing material was superimposed on the black resin layer surface of the light-shielding material of Example 2 and pressed by a heated metal roll to be integrated by heat fusion.
a) light-shielding material.

Example 4 A 25 μm-thick film protective layer made of a linear low-density polyethylene (density = 0.925 g / cm ³ , MFR = 8.5 g / 10 min.) Resin was formed on the nonwoven fabric surface of the laminate of Example 3. Example 4
(See FIG. 5).

COMPARATIVE EXAMPLE 1 Du Pont's trade name: Tyvek 700AG manufactured by fiberizing high-density polyethylene by flash spinning.
A simple substance having a basis weight of 41 g / m ² was used.

COMPARATIVE EXAMPLE 2 A mixture of a polyvinyl chloride resin and a silver pigment was molded.
A 100 μm thick silver agricultural film was used.

[0036]

[Table 1]

As can be seen from the results shown in Table 1, the light-shielding materials of the examples are excellent in mechanical strength, and in particular, show 99.999% which can be recognized as complete light-shielding in this measurement method. It was confirmed that the nonwoven fabric alone and the conventional silver agricultural plastic film alone had a low light-shielding level. Actually, when the chrysanthemum was used for the outer lining of an agricultural house for short-day cultivation of chrysanthemums, the high-strength and dimensional stability possessed by the light-shielding material of the example became easy to spread and excellent in handleability. Then, when observing the cultivation state of chrysanthemum in house cultivation, it was found that there was no adhesion of water droplets on the ceiling, and in addition to sufficient shading, the heat storage of the material was suppressed by the characteristics of high light reflectance and low light absorption. By maintaining the heat retention at night while suppressing the excessive rise in the house temperature during the day, the quality is higher than that of chrysanthemums grown in a conventional house covered with shading materials, and the incidence of disease is reduced. And the flowering rate could be evaluated to be extremely high.

[0038]

The light-shielding material for agricultural and horticultural use according to the present invention is a laminate composed of a white nonwoven fabric on the front surface and a black resin layer on the rear surface as a basic structure. The white nonwoven fabric has high reflectance and low absorption for sunlight. From, since the heat storage can be reduced, suppressing the excessive temperature rise of the interior covered with this light-shielding material, and has the effect of maintaining the heat retention in the low-temperature period, the black resin layer is insufficient with the nonwoven fabric alone It enhances the light-shielding properties and enables complete blocking of sunlight. In addition, such a basic structure can be easily designed to improve mechanical strength by laminating a reinforcing material as necessary, or to impart drip-proof property with a surfactant, and can be used for short-day flowers. It is useful as a shading material suitable for processing cultivation and soft-white cultivation of vegetables.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing an embodiment of a basic structure of a light shielding material of the present invention.

FIG. 2 is a partially broken plan view showing an embodiment of the basic structure of the light shielding material of the present invention.

FIG. 3 is a cross-sectional view showing another embodiment of the light-shielding material of the present invention, in which a black resin layer has a two-layer structure.

FIG. 4 is a cross-sectional view showing another embodiment of the light-shielding material of the present invention, showing a form including a reinforcing material.

FIG. 5 is a cross-sectional view showing another embodiment of the light-shielding material of the present invention, showing a form including a protective layer.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Shading material 2 Nonwoven fabric 3 Black resin layer 31 First black resin layer 32 Second black resin layer 4 Reinforcement 5 Protective layer

Claims (5)

[Claims] An agricultural and horticultural light-shielding device comprising: a white nonwoven fabric on which synthetic resin long fiber filaments are deposited and bonded at high density; and a black resin layer containing carbon black on the back surface. Materials. 2. A laminate having a white nonwoven fabric surface on which synthetic resin long fiber filaments are deposited and bonded at high density and a black resin layer containing carbon black on a back surface, wherein an intermediate layer of the laminate is provided. Alternatively, a light-shielding material for agriculture and horticulture, wherein a reinforcing material is laminated and integrated on the lowermost layer. 3. The agricultural and horticultural light-shielding material according to claim 1, wherein a film protective layer having transparency is formed on the outermost surface of the nonwoven fabric. 4. The nonwoven fabric has a basis weight of 30 to 100 g / m ² , and the black resin layer contains carbon black in an amount of 2 to 20% by weight.
The agricultural and horticultural light-shielding material according to any one of claims 1 to 3, which is a layer having a thickness of 30 to 100 µm. 5. The agricultural and horticultural light-shielding material according to claim 1, wherein the black resin layer has a multilayer structure.