JP2011050307A - Crop sheet for preventing high-temperature injury - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a crop sheet for preventing high-temperature injury not inhibiting growth of cultivated crops while preventing occurrence of high-temperature injury. <P>SOLUTION: The crop sheet for preventing high-temperature injury is made of a cloth-like body formed by intersecting thermoplastic resin uniaxial stretching yarns with one another in all directions. The uniaxial stretching yarn contains tungstic oxide fine particles shown by the general formula, WO<SB>X</SB>(wherein 2.45≤x≤2.999), and/or contains complex tungstic oxide fine particles shown by the formula, M<SB>y</SB>WO<SB>Z</SB>(wherein M is at least one kind of element selected from among Cs, Rb, K, Tl, In, Ba, Li, Ca, Sr, Fe, Sn, Al and Cu, 0.1≤y≤0.5, and 2.2≤z≤3.0) and having a hexagonal crystal structure. The void ratio of the cloth-like body is 5-80%. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to a high-temperature damage prevention sheet for crops, and more particularly, has high visible light transmittance and does not inhibit the growth of cultivated crops, and blocks heat rays to prevent high-temperature damage of the cultivated crops. The present invention relates to a high temperature failure prevention sheet for crops to be prevented.

  In the cultivation of agricultural crops, there is a problem that, due to strong sunlight irradiation during the summer day, high temperature damage occurs in the cultivated crops, resulting in a decrease in yield and a decrease in quality. In order to avoid the high temperature obstacle, in summer, a sun cover sheet is hung on the cultivated crop to block sunlight.

  However, when a sun-covered sheet is hung on a cultivated crop, heat rays composed of infrared rays and near-infrared rays are blocked, and at the same time, visible light necessary for the cultivated crop is also blocked. Occurs.

  In order to solve the problem, Patent Document 1 proposes to hang a sun-covered sheet made of a thermoplastic resin added with lanthanum hexaboride or antimony-containing tin oxide as a light absorbing material on a cultivated crop. . This is because lanthanum hexaboride and antimony-containing tin oxide have a high visible light transmittance and a large blocking effect on infrared rays and near infrared rays, so that it was thought that high temperature damage could be prevented without inhibiting the growth of cultivated crops. .

JP 2004-141051 A

Patent Document 1 proposes that a thermoplastic resin to which a powder that absorbs infrared rays and near infrared rays is added is formed into a film shape or a sheet shape and used as a cover film or a cover sheet.
However, according to the study of the present inventor, when a crop is covered with a film or sheet-shaped sun covering material, the inside of the sun covering material is difficult to ventilate, even if the amount of heat ray transmission is reduced, There was a problem that high-temperature air stayed inside the cover and the atmospheric temperature of the crop became excessively high, resulting in high-temperature damage to the cultivated crop.

  The present invention has been made under the above-described circumstances, and the problem to be solved is to provide a high-temperature damage prevention sheet for crops that does not inhibit the growth of cultivated crops while avoiding the occurrence of high-temperature damage. Is to provide.

As a result of continual research to solve the above problems, the present inventor has obtained tungsten oxide fine particles represented by the general formula WO _X (2.45 ≦ x ≦ 2.999) as fine particles having a heat ray shielding function, And / or applying composite tungsten oxide fine particles represented by the general formula M _Y WO _Z (0.1 ≦ y ≦ 0.5, 2.2 ≦ z ≦ 3.0) and having a hexagonal crystal structure. The present inventors have found that the above-mentioned problems can be achieved by producing a yarn containing fine particles having the heat ray shielding function and using a fabric-like high temperature failure prevention sheet for crops produced from the yarn. It was.

That is, the first configuration of the present invention for solving the above-described problem is
A high-temperature damage prevention sheet for crops comprising a cloth-like body formed by intersecting longitudinally and laterally uniaxially stretched thermoplastic resin,
The uniaxially drawn yarn is a tungsten oxide fine particle represented by a general formula WO _X (where 2.45 ≦ x ≦ 2.999) and / or a general formula M _y WO _Z (where M is Cs, Rb , K, Tl, In, Ba, Li, Ca, Sr, Fe, Sn, Al, Cu, one or more elements selected from 0.1 ≦ y ≦ 0.5, 2.2 ≦ z ≦ 3. 0) and containing composite tungsten oxide fine particles having a hexagonal crystal structure,
A high-temperature damage prevention sheet for crops, wherein the cloth-like body represented by the following formula (1) has a porosity of 5 to 80%.

The second configuration is
The solar light transmittance (%) of the wavelength 200-2100 nm of the cloth-like body is 10% or more lower than the visible light transmittance (%) of the wavelength 400-780 nm of the cloth-like body. It is the high temperature failure prevention sheet for crops as described in the 1st composition.

The third configuration is
In the cloth-like body, a tape-shaped uniaxially stretched yarn in which a bonding layer made of a thermoplastic resin having a melting point lower than that of the base layer is laminated on at least one surface of the base layer intersects longitudinally and laterally, and the intersection is thermally fused. A high-temperature damage prevention sheet for crops according to any one of the first and second configurations.

The fourth configuration is
The uniaxially drawn yarn is a base layer made of high-density polyethylene or polypropylene, and one or more selected from low-density polyethylene, linear low-density polyethylene, ethylene / propylene copolymer, and ethylene / vinyl acetate copolymer. The high-temperature damage prevention sheet for crops according to any one of the first to third configurations, wherein the bonding layer is laminated.

  The high-temperature damage prevention sheet for crops according to the present invention has high strength, excellent durability, and high visible light transmittance, so that the growth of the crop is excellent, and the high-temperature damage of the cultivated crop is prevented by blocking heat rays. Furthermore, high temperature damage of crops due to excessive retention of high temperature air and excessively high ambient temperature can be prevented. Moreover, it has the effect | action which relieves cooling at night.

It is a schematic diagram which shows an example of the high temperature failure prevention sheet | seat for crops which concerns on this invention. (A) It is a top view of the high temperature failure prevention sheet for crops concerning this invention. (B) It is a longitudinal cross-sectional view of the high temperature failure prevention sheet for crops concerning this invention. It is a longitudinal cross-sectional view which shows the other example of the high temperature failure prevention sheet | seat for crops which concerns on this invention. It is a schematic diagram of the perspective view which shows the structure of the uniaxially stretched yarn which concerns on this invention. (A) A uniaxially stretched yarn that is formed into a tape shape by slitting a heat ray shielding thermoplastic resin film to a predetermined width and uniaxially stretching. (B) A uniaxially drawn yarn in which a number of cuts are made in a tape-like body of heat ray shielding thermoplastic resin. (C) A uniaxially stretched yarn in which ultrafine longitudinal ribs are provided on a tape-like body of heat ray shielding thermoplastic resin. It is a schematic diagram of the longitudinal cross-sectional view which shows the example of the uniaxially stretched yarn which concerns on this invention. (A) A uniaxially drawn yarn of a single layer. (B) A uniaxially stretched yarn in which a bonding layer made of a thermoplastic resin having a melting point lower than that of the base layer is laminated on one surface of the base layer. (C) A uniaxially stretched yarn in which a bonding layer made of a thermoplastic resin having a melting point lower than that of the base layer is laminated on both surfaces of the base layer. (D) A uniaxially drawn yarn having a seascore structure in which a bonding layer is formed on a base layer. (E) A uniaxially drawn yarn having a side-by-side structure in which a bonding layer is formed on a base layer.

そして、例えば、図１に示すように、本発明に係る作物用高温障害防止シート１は、熱線の透過を抑制する効果を付与した熱可塑性樹脂を一軸延伸した一軸延伸糸２ａ、２ｂを用いて形成した布状体３によって構成される。
以下、本発明に係る作物用高温障害防止シート１について、構成要素毎に詳細に説明する。 Embodiments for carrying out the present invention will be described with reference to the drawings.
FIG. 1 is a schematic view showing an example of a high temperature failure prevention sheet for crops according to the present invention, and FIG. 2 is a longitudinal sectional view showing another example of the high temperature failure prevention sheet for crops according to the present invention.
1 and 2, a high temperature failure prevention sheet 1 for crops according to the present invention includes a cloth-like body 3 (a predetermined direction in the cloth-like body 3) formed by intersecting uniaxially stretched thermoplastic resin vertically and horizontally. 2a and a uniaxially drawn yarn having a direction intersecting with the uniaxially drawn yarn 2a. In the crop high-temperature failure prevention sheet 1 according to the present invention, the uniaxially stretched yarns 2a and 2b are tungsten oxide fine particles represented by the general formula WO _X (where 2.45 ≦ x ≦ 2.999), and / or , general formula _M y WO _Z (where, M is, Cs, Rb, K, Tl , in, Ba, Li, Ca, Sr, 1 or more elements selected Fe, Sn, Al, from Cu, 0. 1 ≦ y ≦ 0.5, 2.2 ≦ z ≦
3.0) and a composite tungsten oxide fine particle having a hexagonal crystal structure, and the porosity of the cloth-like body 3 represented by the following formula (1) is 5 to 80%. It is characterized by being.

And, for example, as shown in FIG. 1, the crop high temperature failure prevention sheet 1 according to the present invention uses uniaxially stretched yarns 2a and 2b obtained by uniaxially stretching a thermoplastic resin imparted with an effect of suppressing transmission of heat rays. The cloth-like body 3 is formed.
Hereinafter, the high temperature failure prevention sheet 1 for crops according to the present invention will be described in detail for each component.

(1) Heat ray shielding material contained in uniaxially drawn yarn (a) Tungsten oxide fine particles As tungsten oxide fine particles represented by the general formula WO _X (where 2.45 ≦ x ≦ 2.999), for example, W ₁₈ O ₄₉ , W ₂₀ O ₅₈ , W ₄ O _{11 and the} like can be mentioned. If the value of x is 2.45 or more, it is possible to completely avoid the appearance of the undesired WO ₂ crystal phase in the heat ray shielding material and to obtain the chemical stability of the material. I can do it. On the other hand, if the value of x is 2.999 or less, a sufficient amount of free electrons is generated, and an efficient heat ray shielding material is obtained. If the value of x is 2.95 or less, it is more preferable as a heat ray shielding material. A WO _X compound in which the range of x is 2.45 ≦ x ≦ 2.999 is included in a compound called a so-called magnetic phase.

(B) Composite tungsten oxide fine particles General formula MyWO _Z (where M is one or more selected from Cs, Rb, K, Tl, In, Ba, Li, Ca, Sr, Fe, Sn, Al, Cu) As the composite tungsten oxide fine particles having a hexagonal crystal structure represented by the following elements: 0.1 ≦ y ≦ 0.5, 2.2 ≦ z ≦ 3.0), Cs _0.33 WO ₃ , Rb _0.33 WO ₃ , K _0.33 WO ₃ , Ba _0.33 WO _{3 and the} like can be mentioned. If y and z are within the above ranges, useful heat ray shielding characteristics can be obtained. Can do. The addition amount of the additive element M is preferably 0.1 or more and 0.5 or less, and more preferably around 0.33. This is because the value theoretically calculated from the hexagonal crystal structure is 0.33, and preferable optical characteristics can be obtained with the addition amount before and after this. Moreover, about the range of Z, 2.2 <= z <= 3.0 is preferable. This is because the same mechanism works as the above-described tungsten oxide material represented by WO _x in the composite tungsten oxide material represented by MyWO _Z , and the above-described element is also obtained when z ≦ 3.0. This is because free electrons are supplied by adding M. However, from the viewpoint of optical properties, 2.2 ≦ z ≦ 2.99 is more preferable, and 2.45 ≦ z ≦ 2.99 is more preferable.

(C) tungsten oxide microparticles and tungsten oxide microparticles indicated by the general formula WO _X manufacturing method described above of the composite tungsten oxide nanoparticles, the general formula M _Y WO _Z composite tungsten oxide fine particles to be notation, tungsten The compound starting material can be obtained by heat treatment in an inert gas atmosphere or a reducing gas atmosphere.

First, the tungsten compound starting material will be described.
For the tungsten compound starting material, tungsten trioxide powder, tungsten dioxide powder, hydrate of tungsten oxide, tungsten hexachloride powder, ammonium tungstate powder, or tungsten hexachloride was dissolved in alcohol. Tungsten oxide hydrate powder obtained by post-drying, or tungsten oxide hydrate powder obtained by dissolving tungsten hexachloride in alcohol and then adding water to precipitate it and drying it Or one or more selected from a tungsten compound powder obtained by drying an ammonium tungstate aqueous solution and a metal tungsten powder.

Here, in the case of producing tungsten oxide fine particles, from the viewpoint of ease of the production process, tungsten oxide hydrate powder, tungsten trioxide, or tungsten compound powder obtained by drying ammonium tungstate aqueous solution, More preferably, is used.
On the other hand, when producing composite tungsten oxide fine particles, it is more preferable to use an ammonium tungstate aqueous solution or a tungsten hexachloride solution from the viewpoint that each element whose starting material is a solution can be easily mixed uniformly.
By using these raw materials and heat-treating them in an inert gas atmosphere or a reducing gas atmosphere, the above-described tungsten oxide fine particles and composite tungsten oxide fine particles can be obtained.

Furthermore, the heat ray shielding material fine particle containing the composite tungsten oxide fine particle represented by the general formula _MY WO _Z containing the element M is a heat ray shielding containing the tungsten oxide fine particle represented by the general formula WO _X described above. It is the same as the tungsten compound starting material of the material fine particles, and since the M element is added, a tungsten compound containing the element M in the form of a single element or a compound is used as the starting material.

  Here, in order to produce a starting material in which each component is uniformly mixed at the molecular level, it is preferable to mix each material with a solution, and the tungsten compound starting material containing the element M is dissolved in a solvent such as water or an organic solvent. Preferably it is possible. Examples include tungstate, chloride, nitrate, sulfate, oxalate, oxide, carbonate, hydroxide, etc. containing element M, but are not limited to these and are in solution form Is preferable.

Next, heat treatment in an inert gas atmosphere or a reducing gas atmosphere will be described.
First, the heat treatment conditions in an inert gas atmosphere are preferably 650 ° C. or higher. The starting material heat-treated at 650 ° C. or higher has a sufficient near-infrared absorbing power and is efficient as heat ray shielding fine particles. As the inert gas, an inert gas such as Ar or N ₂ is preferably used.

As the heat treatment conditions in the reducing atmosphere, the starting material is first heat-treated at 100 ° C. or more and 650 ° C. or less in the reducing gas atmosphere, and then at a temperature of 650 ° C. or more and 1200 ° C. or less in the inert gas atmosphere. It is better to heat-treat with. The reducing gas at this time is not particularly limited, but H ₂ is preferable. Then, when H ₂ is used as the reducing gas, the composition of the reducing atmosphere, for example, Ar, preferably mixed with 0.1% or more by volume of H ₂ in an inert gas such as N _2, More preferably, 0.2% or more is mixed. H ₂ can be advanced efficiently reduced if more than 0.1% by volume.
The starting material powder reduced with hydrogen contains a Magneli phase and exhibits good heat ray shielding properties. Therefore, even in this state, it can be used as heat ray shielding fine particles.

  The surface of the tungsten oxide fine particles and the composite tungsten oxide fine particles according to the present invention is a compound containing at least one of Si, Ti, Zr, and Al, preferably an oxide coated and surface-treated. It is preferable from the viewpoint of improving weather resistance.

As described above, the high temperature failure prevention sheet 1 for crops according to the present invention is a uniaxially stretched uniaxially stretched thermoplastic resin to which the tungsten oxide fine particles and composite tungsten oxide fine particles are added and dispersed, and the effect of shielding heat rays is imparted. It is comprised by the cloth-like body 3 formed using the drawn yarns 2a and 2b.
The thermoplastic resin forming the uniaxially stretched yarns 2a and 2b includes tungsten oxide fine particles represented by the general formula WO _X having a heat ray shielding function (where 2.45 ≦ x ≦ 2.999), and / or formula _M y WO _Z (where, M is, Cs, Rb, K, Tl , in, Ba, Li, Ca, Sr, 1 or more elements selected Fe, Sn, Al, from Cu, 0.1 ≦ y ≦
0.5, 2.2 ≦ z ≦ 3.0) and composite tungsten oxide fine particles having a hexagonal crystal structure must be added.

  Tungsten oxide fine particles and composite tungsten oxide fine particles having a heat ray shielding function according to the present invention absorb a large amount of light in the near infrared region, particularly 1000 nm or more. Therefore, the transmitted color tone is often a blue color tone. .

The dispersed particle diameter of the tungsten oxide fine particles and composite tungsten oxide fine particles can be appropriately selected depending on the purpose of use.
For example, when used for an application that maintains visible light transmission, the tungsten oxide fine particles and the composite tungsten oxide fine particles preferably have a dispersed particle diameter of 800 nm or less. This is because if the dispersed particle diameter is smaller than 800 nm, light is not completely blocked by scattering, the transparency in the visible light region is maintained, and at the same time, heat rays made of near infrared rays can be efficiently shielded. . In the present invention, the dispersed particle diameter means dynamic light scattering for the tungsten oxide fine particles and the composite tungsten oxide fine particle dispersion obtained by dispersing the tungsten oxide fine particles and the composite tungsten oxide fine particles in an arbitrary solvent. It is the average value measured with the measuring apparatus (ELS-800 (made by Otsuka Electronics Co., Ltd.)) using the method.

In order to obtain the desired heat ray shielding uniaxially drawn yarn 2, the powder color of the tungsten oxide fine particles and the composite tungsten oxide fine particles is an L ^* a ^* b ^* table recommended by the International Commission on Illumination (CIE). In the powder color in the color system (JIS Z 8729), it is desirable to satisfy the conditions that L ^* is 25 to 80, a ^* is -10 to 10, and b ^* is -15 to 15.
By using the tungsten oxide fine particles and composite tungsten oxide fine particles having the powder color, the transmittance of visible light is high, the growth of cultivated crops is excellent, and the high temperature of the cultivated crops is prevented by blocking heat rays. The high temperature failure prevention sheet 1 for crops can be obtained.

(2) High temperature failure prevention sheet for crops As shown in FIGS. 1 and 2, the high temperature failure prevention sheet for crops 1 of the present invention adds and disperses the above-described tungsten oxide fine particles and composite tungsten oxide fine particles to shield heat rays. It is comprised by the cloth-like body 3 formed using the uniaxially stretched yarn 2a, 2b which uniaxially stretched the thermoplastic resin which provided the effect.

(A) Heat ray shielding thermoplastic resin film As described above, the uniaxially stretched yarns 2a and 2b shown in FIGS. 1 and 2 have the effect of shielding heat rays by adding and dispersing the tungsten oxide fine particles and composite tungsten oxide fine particles. It is obtained by uniaxially stretching a thermoplastic resin.
Then, the manufacturing method of the said heat ray shielding thermoplastic resin film is demonstrated.

The method for producing the heat ray-shielding thermoplastic resin film can be arbitrarily selected as long as it is a method capable of uniformly dispersing the tungsten oxide fine particles and composite tungsten oxide fine particles serving as heat ray shielding components in the resin. For example, it is possible to use a method in which the fine particles are directly added to the resin and uniformly melt-mixed. In particular, an additive liquid in which fine particles of a heat ray shielding component are added and dispersed in a solvent is prepared, and a molding composition obtained by mixing the additive liquid with a resin or a resin raw material is obtained, and a resin sheet is obtained using the molding composition. The method of molding is simple and preferable.
The amount of the tungsten oxide fine particles and composite tungsten oxide fine particles added to the resin is not particularly limited, but is preferably between 0.5 wt% and 10 wt%. If the amount used is 0.5% by weight or more, a sufficient heat ray shielding effect can be obtained even if the heat ray shielding thermoplastic resin film material is thin, and if it is 10% by weight or less, a cloth as a heat ray shielding thermoplastic resin film material can be obtained. This is because it is possible to avoid a decrease in the formability. The addition amount is selected in consideration of the porosity of the cloth-like body obtained using the uniaxially drawn yarn of the heat ray shielding thermoplastic resin film material.

  The method for dispersing the heat ray shielding component in the resin is not particularly limited as long as the fine particles can be uniformly dispersed in the resin, but a method using an additive solution in which the fine particles are dispersed in an arbitrary solvent as described above is preferable. Specifically, for example, by using a method such as a bead mill, a ball mill, a sand mill, or an ultrasonic dispersion, the fine particles are dispersed in an arbitrary solvent to obtain an additive liquid for producing a heat ray shielding thermoplastic resin film.

  Further, a mixture in which fine particles are uniformly dispersed in the resin can also be prepared by a method in which the solvent of the additive solution is removed by a known method and the obtained powder is added to the resin and uniformly melted and mixed.

The dispersion solvent used in the additive solution for producing the heat ray shielding thermoplastic resin film material is not particularly limited, and can be selected according to the conditions for forming the resin to be blended and the resin sheet material. Organic solvents can be used. Moreover, you may adjust pH by adding an acid and an alkali as needed. Furthermore, in order to further improve the dispersion stability of the fine particles in the resin, various surfactants, coupling agents and the like can be added as a dispersant.

  In order to produce a heat ray shielding thermoplastic resin film material using the above additive solution, generally, the additive solution is added to a resin as a main material, mixed with a ribbon blender, tumbler, nauter mixer, Henschel. Uniform fine particles in the resin using a mixer, super mixer, planetary mixer and other mixers, and Banbury mixer, kneader, roll, single screw extruder, twin screw extruder, etc. A mixture dispersed in is prepared.

  As the thermoplastic resin constituting the uniaxially stretched yarn obtained from the heat ray shielding thermoplastic resin film material, a resin having a large stretching effect, generally a crystalline resin is suitable. Specifically, high density polyethylene, medium density polyethylene, polypropylene, olefin polymers such as ethylene / α-olefin copolymer, ethylene / vinyl acetate copolymer, polyester such as polyethylene terephthalate and polybutylene terephthalate, nylon 6 Polyamide such as nylon 66, acrylonitrile, vinylon, or the like can be used. Of these, olefin polymers such as high-density polyethylene, medium-density polyethylene, linear low-density polyethylene, and polypropylene are desirable from the viewpoint of processability and economy.

The heat ray shielding thermoplastic resin film according to the present invention is obtained by molding a mixture in which fine particles are uniformly dispersed in a resin as described above into a flat shape by a known molding method such as injection molding, extrusion molding, compression molding or the like. Can be produced. In addition, a heat ray shielding thermoplastic resin film can also be produced by the same method after once pelletizing a mixture in which fine particles are uniformly dispersed in a resin with a granulator.
In addition, the thickness of a heat ray shielding thermoplastic resin film can be adjusted to arbitrary thickness as needed.

  In this way, tungsten oxide fine particles and composite tungsten oxide fine particles having strong absorption in the near-infrared region as heat ray shielding components are uniformly dispersed in the above resin material and formed into a sheet shape, thereby achieving high-cost physical film formation. It is possible to provide a heat ray shielding thermoplastic resin film having a heat ray shielding function and having high transmission performance in the visible light region without using a method or a complicated bonding process.

(B) Uniaxially drawn yarn In the present invention, the uniaxially drawn yarn that forms the high-temperature failure prevention sheet for crops broadly means a filament that can form a sheet-like body, and is a tape-like body, string-like body, monofilament, multi-filament It contains filaments such as filaments, and these are twisted as necessary.

Here, the uniaxially stretched yarn according to the present invention will be described with reference to FIG.
The structure of the uniaxially stretched yarn 2 may be anything. For example, as shown in FIG. 3A, a heat ray shielding thermoplastic resin film is slit into a predetermined width and uniaxially stretched to form a tape shape. It can be used as a flat yarn. As shown in FIG. 3B, a split yarn in which a number of cuts 5 are formed in a tape-like body can also be used. Furthermore, as shown in FIG. 3C, the tape-like body can be provided with very thin longitudinal ribs 6, and by providing the ribs 6, the reflected light of the sun is scattered to reduce the influence on the environment. Can do.

In addition, the cross section can be a uniaxially drawn yarn 2 having a round shape, an oval shape, a square shape, a polygonal shape, or other irregular shape. Further, a mixture of different types of resins is extruded into a filament, and a gap between the resins is formed. It is possible to increase the suppleness by using a dumbline that is split and fibrillated. Moreover, one piece can be used alone as a woven yarn, and several pieces can be bundled and used.

  The uniaxially stretched yarn 2 may be a single layer as shown in FIG. 4 (A), or as shown in FIGS. 4 (B) and 4 (C), on one or both sides of the base layer 7. It can be set as the laminated uniaxially drawn yarn 2 in which the joining layer 8 made of a thermoplastic resin having a melting point lower than that of the base layer is formed. Furthermore, the bonding layer 8 may have a seascore structure as shown in FIG. 4D and a side-by-side structure as shown in FIG.

(C) Monolayer of uniaxially stretched yarn, base layer and bonding layer of laminate The thermoplastic resin constituting the monolayer of uniaxially stretched yarn 2 or base layer 7 of the laminate is the stretching effect described in (a). A large resin is used.
On the other hand, the joining layer 8 joins the uniaxially stretched yarns 2 after the uniaxially stretched yarns 2 are woven, and has a lower melting point than that of the thermoplastic resin constituting the base layer 7 and is excellent in heat fusion properties. Resin is used. Specifically, olefins such as high-pressure low-density polyethylene, linear low-density polyethylene, high-density polyethylene, polypropylene, ethylene / propylene copolymer, ethylene / α-olefin copolymer, ethylene / vinyl acetate copolymer, etc. Polymers, polyesters such as polyethylene terephthalate and polybutylene terephthalate, polyamides such as nylon 6 and nylon 66 can be used, and the melting point of the base layer is lower than that of the base layer, preferably 20 ° C. or higher. A plastic resin is selected. In particular, olefin polymers such as high-pressure method low-density polyethylene, high-density polyethylene, linear low-density polyethylene, and polypropylene are desirable, and linear low-density polyethylene polymerized using a metallocene catalyst is particularly preferable.

The thermoplastic resin forming the uniaxially stretched yarn 2 can be blended with various additives as required. For example, oxidation such as phenol-based, organic phosphite-based, phosnite-based organic phosphorus-based, thioether-based, etc. Inhibitors; Light stabilizers such as hindered amines; UV absorbers such as benzophenones, benzotriazoles, and benzoates; Antistatic agents; Dispersants such as bisamides, waxes, and organometallic salts; Alkaline earth metal salts Carboxylic acid-based chlorine scavengers; Amide-based, wax-based, organometallic salt-based, ester-based lubricants; Hydrazine-based, amine-acid-based metal deactivators; Bromine-containing organic-based, phosphoric acid-based, etc. Flame retardants; organic pigments; inorganic pigments; inorganic and organic antibacterial agents such as metal ions can be added.
These additives are appropriately combined and blended in any step of manufacturing the material composition of the base layer 7 and the bonding layer 8. The blending of the additive may be prepared by mixing at a predetermined ratio using a kneading device such as a conventional known twin screw extruder, Banbury mixer, kneader, mixing roll, and melt-kneading the mixture. A so-called master batch having a high concentration may be prepared and used after being diluted.

  When the laminated uniaxially drawn yarn 2 is used, as a means for forming a laminated film that becomes a molding material of a laminated flat yarn or a laminated split yarn, a film that becomes the base layer 7 and a film that becomes the bonding layer 8 are formed in advance. Means for forming a multilayer using a dry laminating method or a thermal laminating method, a method of coating a thermoplastic resin to be the bonding layer 8 on the surface of the film to be the base layer 7, a bonding layer 8 to the film to be the base layer 7 formed in advance. Any known means such as extrusion laminating or extrusion molding as a laminated film by multilayer coextrusion may be appropriately selected and used. Ease of molding and cost, and adhesion between each layer of the product In this respect, a method of obtaining a laminated body of the base layer 7 and the bonding layer 8 in one step by a multilayer coextrusion method is desirable. The seascore structure or side-by-side structure is generally based on a coextrusion method.

Further, as a means for drawing the uniaxially drawn yarn 2, a heat ray shielding thermoplastic resin film that becomes the base layer 7 is drawn in a uniaxial direction, and then a thermoplastic resin that becomes the bonding layer 8 is laminated, and this is formed into a tape shape. It may be slit, or may be obtained by stretching in a uniaxial direction before or after slitting the laminated film in which the base layer 7 and the bonding layer 8 are laminated. The draw ratio is usually about 3 to 10 times.

  The thickness of the uniaxially stretched yarn 2 is not limited and can be arbitrarily set according to the purpose. Generally, the thickness is 50 to 10,000 decitex (where decitex is a unit of fiber thickness, 1 g / 10000 m is 1 dtex), preferably 100 to 5000 dtex, and when the uniaxially stretched yarn 2 is in the form of a tape, the yarn width is 0.3 to 200 mm, preferably 0.5 to 100 mm, and the yarn thickness is 5 The range is set to ˜500 μm.

When the layer structure of the uniaxially stretched yarn 2 is a three-layer structure, generally, the thickness composition ratio is set as bonding layer: base layer: bonding layer = 1: 98: 1 to 25:50:25.
(3) Cloth-like body

  The uniaxially drawn yarn 2 thus obtained can be woven into a plain weave to form a cloth-like body 3 as shown in FIGS. Further, it can be made into a cloth-like body 3 by weaving in a twill weave, a twill weave, a knit weave, a double weave, a double knit, a pattern weave, etc., and further knitted into a vertical knitting, a weft knitting, a raschel knitting, a tricot knitting, etc. It is also possible to make a cloth-like body. As a loom for weaving, a known loom such as a circular loom, a slewer loom, a water jet loom can be used. Further, as shown in FIG. 2, a cross bond in which a plurality of uniaxially drawn yarns 2a are arranged in parallel, and another uniaxially drawn yarn 2b is arranged in parallel in the direction intersecting with the uniaxially drawn yarn 2a and the intersection is thermally bonded. It can be set as the cloth-like body 3 which consists of cloth (soft).

The cloth-like body 3 is required to have a porosity of 5 to 80% represented by the following formula (1). Furthermore, it is preferable that it is 10 to 60%. If the porosity is less than 5%, it is difficult to avoid the temperature rise inside the covered sheet due to the retention of high-temperature air, and if it exceeds 80%, the heat ray blocking effect is reduced to prevent high-temperature failure. Will be less effective.

As a method for controlling the transmittance of visible light, the amount of tungsten oxide fine particles and composite tungsten oxide fine particles added to the base layer 7 or the bonding layer 8 constituting the uniaxially drawn yarn 2, the fineness of the uniaxially drawn yarn 2, and history. It can be adjusted according to the number of yarns to be driven.
And with respect to the value of visible light transmittance (%) at a wavelength of 400 to 780 nm that the cloth-like body 3 has, the value of solar transmittance (%) at a wavelength of 200 to 2100 nm that the cloth-like body 3 has is 10% or more lower. By doing so, the high-temperature damage prevention sheet for crops can be obtained, which can prevent the high-temperature damage of the cultivated crop by blocking the heat rays, and at the same time can ensure the transmittance of visible light and is excellent in the growth of the crop.

Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples.
However, the present invention is not limited to the following examples.
In addition, the powder color (10 ° field of view, light source D65) of the tungsten oxide fine particles and the composite tungsten oxide fine particles, and the visible light transmittance and the solar transmittance of the heat ray shielding vinyl chloride film in each of the examples and comparative examples are as follows. , Using a spectrophotometer U-4000 manufactured by Hitachi, Ltd.
In addition, the said solar radiation transmittance is an parameter | index which shows the heat ray shielding performance of the high temperature failure prevention sheet | seat for crops.
The haze value was measured based on JIS K 7105 using HR-200 manufactured by Murakami Color Research Laboratory Co., Ltd. The average dispersed particle diameter was an average value measured with a measuring device (ELS-800 (manufactured by Otsuka Electronics Co., Ltd.)) using a dynamic light scattering method for the tungsten oxide fine particles and the composite tungsten oxide fine particle dispersion.

[Example 1]
While supplying 5% H ₂ gas using N ₂ gas as a carrier, a powder obtained by sufficiently mixing 50 g of H ₂ WO ₄ and 17.0 g of Cs (OH) ₂ (equivalent to Cs / W = 0.3) in an agate mortar After heating and reducing treatment at a temperature of 600 ° C. for 1 hour, it was fired at 800 ° C. for 30 minutes in an N ₂ gas atmosphere to obtain heat ray shielding fine particles (hereinafter abbreviated as “fine particles a”). The composition formula of the fine particles a was Cs _0.3 WO ₃ , and the powder color L ^* was 35.2745, a ^* was 1.4918, and b ^* was −5.3118.

Next, 6% by weight of fine particles a, 12% by weight of an acrylic dispersant having a hydroxyl group as a functional group, and 82% by weight of toluene are weighed, and pulverized and dispersed for 6 hours with a paint shaker containing 0.3 mmφZrO ₂ beads. A tungsten oxide fine particle dispersion was obtained. The average dispersed particle diameter of the tungsten oxide fine particles in this dispersion was 120 nm. Here, by removing the solvent from the tungsten oxide fine particle dispersion, a tungsten oxide fine particle dispersion dispersant mixed powder (hereinafter abbreviated as A powder) was prepared.

High density polyethylene (density 0.956 g / cm ³ , melting point 132 ° C.) blended with A powder so that the tungsten oxide fine particles are 2% by weight is used as an intermediate layer, and low density polyethylene (density 0.922 g / cm ^3). Inflation film with a melting point of 113 ° C) is formed, slit to a predetermined width, stretched 7.2 times at 100 ° C with a hot plate, and then subjected to a 6% relaxation treatment at 110 ° C with a hot air oven. Thus, a flat yarn having a width of 400 dt and a width of 1 mm was formed.
Using the flat yarn for warp and weft yarns, weaving the warp and weft density to 10 / 25.4mm each with a slewer loom, and then heat-sealing the intersections of the yarns with a 120 ° C hot roll, A high temperature failure prevention sheet for crops according to Example 1 having a porosity of 37.8% was obtained.

[Example 2]
A high-temperature damage prevention sheet for crops according to Example 2 was obtained in the same manner as Example 1 except that the A powder was blended so that the tungsten oxide fine particles were 3.2% by weight.

[Example 3]
A high-temperature damage prevention sheet for crops according to Example 3 was obtained in the same manner as in Example 1 except that the vertical and horizontal driving densities were 8 / 25.4 mm, respectively.

[Example 4]
Example 4 was carried out in the same manner as in Example 1 except that the A powder was blended so that the tungsten oxide fine particles would be 0.5% by weight, and the vertical and horizontal implantation densities were 19 / 25.4 mm respectively. A high temperature failure prevention sheet for crops according to the present invention was obtained.

[Example 5]
Example 5 was carried out in the same manner as in Example 1 except that the A powder was blended so that the tungsten oxide fine particles would be 10% by weight, and the vertical and horizontal driving densities were 5 / 25.4 mm, respectively.
A high temperature failure prevention sheet for crops according to the present invention was obtained.

[Comparative Example 1]
A high-temperature damage prevention sheet for crops according to Comparative Example 1 was obtained in the same manner as in Example 1 except that the A powder was blended so that the tungsten oxide fine particles were 0.3% by weight.
[Comparative Example 2]
A high temperature failure prevention sheet for crops according to Comparative Example 2 was obtained in the same manner as in Example 1 except that the tungsten oxide fine particles were not added.

  The visible light transmittance and the solar radiation transmittance were measured for the high temperature failure prevention sheets for crops according to Examples 1 to 3 and Comparative Example 1 obtained by the above method. And the outdoor ground is covered in a tunnel shape with the high temperature failure prevention sheet for crops according to Examples 1 to 3 and Comparative Example 1 obtained, the change in the ground temperature is measured, and the maximum for the uncovered state within one day The temperature difference was measured. The results are shown in Table 1.

  The high temperature failure prevention sheet for crops of the present invention can be used as a tunnel-type cover, a house-type cover, and a curtain in a house as a sun cover in crop cultivation, and since the present invention sheet has excellent durability, It can also be used as a sandproof, dustproof, windproof net, etc. that does not hinder growth.

1. 1. High temperature damage prevention sheet for crops Uniaxially drawn yarn 2a. Uniaxially drawn yarn 2b having a predetermined direction. 2. uniaxially drawn yarn having a direction intersecting with uniaxially drawn yarn 2a having a predetermined direction; 4. Cloth-like body Break 6. Rib 7. Base layer 8. Bonding layer

Claims (4)

A high-temperature damage prevention sheet for crops comprising a cloth-like body formed by intersecting longitudinally and laterally uniaxially stretched thermoplastic resin,
The uniaxially drawn yarn is a tungsten oxide fine particle represented by a general formula WO _X (where 2.45 ≦ x ≦ 2.999) and / or a general formula M _y WO _Z (where M is Cs, Rb , K, Tl, In, Ba, Li, Ca, Sr, Fe, Sn, Al, Cu, one or more elements selected from 0.1 ≦ y ≦ 0.5, 2.2 ≦ z ≦ 3. 0) and containing composite tungsten oxide fine particles having a hexagonal crystal structure,
A high-temperature failure prevention sheet for crops, wherein the cloth-like body represented by the following formula (1) has a porosity of 5 to 80%.

  The solar light transmittance (%) of the wavelength 200-2100 nm of the cloth-like body is 10% or more lower than the visible light transmittance (%) of the wavelength 400-780 nm of the cloth-like body. The high temperature failure prevention sheet for crops according to claim 1.   In the cloth-like body, a tape-shaped uniaxially stretched yarn in which a bonding layer made of a thermoplastic resin having a melting point lower than that of the base layer is laminated on at least one surface of the base layer intersects longitudinally and laterally, and the intersection is thermally fused. The high-temperature damage prevention sheet for crops according to claim 1 or 2, wherein   The uniaxially drawn yarn is a base layer made of high-density polyethylene or polypropylene, and one or more selected from low-density polyethylene, linear low-density polyethylene, ethylene / propylene copolymer, and ethylene / vinyl acetate copolymer. The high-temperature failure prevention sheet for crops according to any one of claims 1 to 3, wherein the bonding layer is laminated.

Images