JP2017195796A - Agricultural sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an agricultural sheet having repellent effect on the pests that inhibit the growth of crops.SOLUTION: An agricultural sheet 10 has a porous resin sheet 1 having a plurality of cavities present inside, and a reinforcement sheet 2 disposed on one surface side of the porous resin sheet 1. The surface on the reinforcement sheet 2 side has an average reflectance of ultraviolet rays (with wavelengths of 300 nm or more and 380 nm or less) of 35% or more.SELECTED DRAWING: Figure 1

Description

  The present disclosure relates to an agricultural sheet.

  The agricultural sheet is, for example, a member that covers soil or agricultural products or a member of an agricultural house. The agricultural sheet imparted with light reflectivity can be used, for example, to eliminate light shortage in the house, promote coloring of harvested products, suppress ground temperature, and take measures against weeds.

  Patent Document 1 discloses an agricultural sheet including a sheet base material and a light reflection layer provided on one surface of the sheet base material, and the sheet base material has an average diameter of 1 μm to 50 μm. A porous thermoplastic resin sheet having a porosity in the range of 35 to 60% and a thickness in the range of 30 μm to 90 μm. An agricultural sheet having a thickness in the range of 0.5 μm to 4 μm is disclosed.

JP 2014-233206 A

  There is a need for technology to avoid pests that hinder the cultivation of crops. The present disclosure mainly aims to provide an agricultural sheet having a pest repellent effect.

  One of the present disclosure includes a porous resin sheet having a plurality of voids therein, and a reinforcing sheet disposed on one surface side of the porous resin sheet, and the surface on the reinforcing sheet side The agricultural sheet | seat whose average reflectance of the ultraviolet-ray (wavelength 300nm or more and 380nm or less) in is 35% or more is provided.

Another one of the present disclosure includes a porous resin sheet having a plurality of voids therein, and a reinforcing sheet disposed on one surface side of the porous resin sheet, the reinforcing sheet side the average reflectance of UV (380 nm inclusive wavelength 300 nm) in the plane and _{R U} in, the average reflectance of visible light (wavelength equal to or more than 380 nm 780nm or less) and _{R V,} average reflectance in the infrared (wavelength 780nm or 1050nm or less) the when the _{R I, R} U / _{R I} is, is 0.4 or more and 1 or _less, R V / _{R I} is, is 1.1 to _{2.3, (R U + R V +} R I) / 3 provides an agricultural sheet having 60% or more.

  The agricultural sheet of the present disclosure has an effect of having a pest repellent effect.

It is a schematic sectional view showing an example of an agricultural sheet of this indication. It is a schematic sectional drawing which shows the other example of the agricultural sheet | seat of this indication. It is a schematic sectional drawing which shows the other example of the agricultural sheet | seat of this indication. It is a schematic sectional drawing which shows an example of the manufacturing method of the agricultural sheet | seat of this indication. It is the result of the reflection spectroscopy measurement with respect to the agricultural sheet | seat obtained in Examples 1-4 and the comparative example 1. FIG.

  Hereinafter, the agricultural sheet of the present disclosure will be described in detail.

  FIG. 1 is a schematic cross-sectional view showing an example of an agricultural sheet. An agricultural sheet 10 in FIG. 1 includes a porous resin sheet 1 and a reinforcing sheet 2 disposed on one surface side of the porous resin sheet 1. The reinforcing sheet 2 may be disposed directly on the porous resin sheet 1 or may be disposed on the porous resin sheet 1 with another layer interposed therebetween. Further, the reinforcing sheet 2 may be disposed on both sides of the porous resin sheet 1. And the average reflectance of the ultraviolet-ray in the surface at the side of the reinforcement sheet 2 of the agricultural sheet 10 shall be more than predetermined value. The “surface on the reinforcing sheet side of the agricultural sheet” refers to a surface on the opposite side of the surface on which the porous resin sheet is disposed with respect to the reinforcing sheet.

  According to this indication, it can be set as the agricultural sheet which has a pest repellent effect by having ultraviolet reflectance more than predetermined.

As a technique for avoiding pests that hinder the cultivation of crops, there is a technique using light. These technologies have the advantage of low environmental impact. As one of the means for repelling pests using light, there is a method of imparting ultraviolet reflectivity to an agricultural sheet. Although the details of this mechanism have not been fully elucidated, it is presumed that when a pest flies, it will not be able to continue normal flight if it receives ultraviolet rays normally received from the back side from the surface direction.
Hereinafter, the agricultural sheet of the present disclosure will be described for each configuration.

1. Porous resin sheet A porous resin sheet is a resin sheet in which voids exist. The porous resin sheet may contain an additive such as a filler as necessary. The porous resin sheet is more light reflective than the porous structure.

(1) Resin The porous resin sheet contains a resin. The resin may be a thermoplastic resin or a thermosetting resin, but the former is preferred. Examples of the thermoplastic resin include a polyolefin resin, an acrylic resin, a styrene resin, a vinyl fluoride resin, an amide resin, and a saturated ester resin, and among them, a polyolefin resin is preferable. This is because heat resistance, water resistance, chemical resistance and cost are excellent.

  Examples of polyolefin resins include olefin homopolymers, copolymers of two or more olefins, copolymers of one or more olefins and one or more polymerizable monomers that can be polymerized with olefins, and the like. Can be mentioned. Examples of the olefin (monomer unit) include ethylene, propylene, butene, hexene and the like. The copolymer may be a binary system, a ternary system, or a quaternary system. The copolymer may be a random copolymer or a block copolymer.

  Specific examples of the polyolefin-based resin include, for example, a polyethylene-based resin and a polypropylene-based resin, and among them, a polypropylene-based resin is preferable. An example of the polypropylene resin is a propylene homopolymer. The propylene homopolymer preferably has isotactic or syndiotactic stereoregularity. Other examples of polypropylene resins include copolymers of propylene and other α-olefins. Examples of other α olefins include at least one of ethylene, butene-1, hexene-1, and heptene-1,4-methylpentene-1. The polypropylene resin preferably contains propylene as a main component of monomer units.

  On the other hand, examples of the polyethylene-based resin include low density polyethylene and high density polyethylene. The polyethylene resin may be linear polyethylene. The polyethylene resin preferably contains ethylene as a main component of monomer units. Further, as the polyolefin-based resin, poly (4-methylpentene-1), poly (butene-1), an ethylene-vinyl acetate copolymer, or the like may be used.

  As described above, acrylic resin, styrene resin, vinyl fluoride resin, amide resin, ester resin, or the like can be used as the thermoplastic resin. Examples of the acrylic resin include polymethyl acrylate, polymethyl methacrylate, and ethylene-ethyl acrylate copolymer. Examples of the styrene resin include butadiene-styrene copolymer, acrylonitrile-styrene copolymer, polystyrene, styrene-butadiene-styrene copolymer, styrene-isoprene-styrene copolymer, styrene-acrylic acid copolymer, and the like. Is mentioned. Examples of the vinyl fluoride resin include vinyl chloride resins, polyvinyl fluoride, and polyvinylidene fluoride. Examples of the amide resin include 6-nylon, 6,6-nylon, 12-nylon, and the like. Examples of the ester resin include polyethylene terephthalate and polyprebutylene terephthalate. In addition, as the thermoplastic resin, polycarbonate, polyphenylene oxide, polyacetal, polyphenylene sulfide, silicone resin, thermoplastic urethane resin, polyether ether ketone, polyether imide, thermoplastic elastomer, or the like may be used.

  The porous resin sheet may contain one type of resin or may contain two or more types of resins. When two or more kinds of resins are used, a polyolefin resin is preferably the main component, and a polypropylene resin is more preferable. Moreover, content of the resin in a porous resin sheet is 45 mass% or more, for example, and 55 mass% or more may be sufficient as it. On the other hand, the resin content in the porous resin sheet is, for example, 99% by mass or less and may be 98% by mass or less.

(2) Filler The porous resin sheet may contain a filler. By adding a filler and producing a porous resin sheet by stretching, for example, voids are generated inside the porous resin sheet. Examples of the filler include inorganic fillers and organic fillers.

  Examples of the inorganic filler include calcium carbonate such as heavy calcium carbonate and light calcium carbonate, calcined clay, talc, silicon oxide, diatomaceous earth, titanium oxide, magnesium oxide, zinc oxide, and barium sulfate. The inorganic filler may be surface-treated with a fatty acid. Among these, the inorganic filler is preferably heavy calcium carbonate, light calcium carbonate, calcined clay, or talc. This is because it is inexpensive and has good moldability.

  The average particle diameter of the inorganic filler is, for example, from 0.01 μm to 15 μm, and may be from 0.01 μm to 8 μm. In addition, an average particle diameter is defined as a statistical average value of the particle size distribution measured on a volume basis, and refers to, for example, a value measured by LA-920 manufactured by Horiba, Ltd.

  Examples of organic fillers include polyethylene terephthalate, polybutylene terephthalate, polycarbonate, polyamide, polyethylene naphthalate, polystyrene, melamine, polyethylene sulfite, polyimide, polyethyl ether ketone, polyether ether ketone, polyphenylene sulfite, and poly-4. -Methyl-1-pentene, polymethyl methacrylate and the like. Further, the organic filler is a homopolymer of cyclic olefin, a copolymer of cyclic olefin and ethylene, and has a melting point of 120 ° C. or higher and 300 ° C. or lower or a glass transition temperature of 120 ° C. or higher and 280 ° C. or lower. Materials can also be used.

  The content of the filler in the porous resin sheet is, for example, 1% by mass to 65% by mass, and preferably 2% by mass to 55% by mass.

(3) Other additives The porous resin sheet may contain various additives such as a surfactant, a lubricant, and an antistatic material as necessary. By adding a surfactant, for example, condensation can be prevented. Examples of the surfactant include nonionic surfactants, anionic surfactants, and zwitterionic surfactants. Examples of the nonionic surfactant include glycerin fatty acid ester, pentaerythritol fatty acid ester, polyoxypropylene / polyoxyethylene block polymer, and the like. Examples of the anionic surfactant include salts such as sulfonate and alkylbenzene sulfonate. In addition, as said salt, a sodium salt, potassium salt, ammonium salt etc. are mentioned, for example.

  Examples of the lubricant include aliphatic hydrocarbons such as liquid paraffin, synthetic paraffin, and microcrystalline wax, stearic acid esters of linear alcohols, higher fatty acid amides, and the like. Examples of the antistatic material include alkyl diethanolamine, hydroxyalkyl monoethanolamine, glycerin fatty acid ester, polyglycerin fatty acid ester, alkyl sulfonic acid soda, alkyl benzene sulfonic acid soda, and perchloric acid tetraalkyl ammonium salt. In addition, content of an additive is not specifically limited, According to the kind of additive, it selects suitably.

(4) Porous resin sheet A porous resin sheet usually has voids therein. Although the porosity of a porous resin sheet is not specifically limited, For example, it is 35% or more and 60% or less, and it is preferable that they are 40% or more and 58% or less. If the porosity is too low, moisture permeability and air permeability may be lowered. If the porosity is too high, the sheet strength may be weakened.

The porosity means the ratio of voids in the porous resin sheet, and can be calculated by the following formula 1.
Porosity (%) = {(ρo−ρ) / ρo} × 100 (Expression 1)
In Formula 1, ρ is the density of the porous resin sheet, and conforms to JIS P 8118. ρo is the true density of the porous resin sheet. The true density can be determined by analyzing the types of main material components constituting the porous resin sheet and their constituent ratios and using general values of the types of material components. For example, the density of polypropylene is 0.9 g / cm ³ and the density of calcium carbonate is 2.7 g / cm ³ . In addition, when the porous resin sheet has been subjected to stretching treatment, the true density is substantially equal to the density of the material before stretching unless the material before stretching contains a large amount of air. Therefore, the true density may be obtained from a material before stretching, and can be obtained by a dry density measuring method by a constant volume expansion method. As a measuring device, for example, a dry automatic densimeter Accupic manufactured by Shimadzu Corporation is available. 1330.

  The average diameter of the voids is, for example, 1 μm or more and 50 μm or less, preferably 2 μm or more and 40 μm or less, and more preferably 5 μm or more and 30 μm or less. Note that the average diameter (L) of the void and the maximum diameter (M) in the direction perpendicular thereto are measured and averaged [(L + M) / 2] as the void diameter. The diameter of at least n (n is an integer of 1 or more, and preferably an integer of 100 or more) is measured, and the average value is defined as the average diameter of the voids. For example, a scanning electron microscope S-2400 manufactured by Hitachi, Ltd. can be used for cross-sectional observation of the sample.

  Since the porous resin sheet has voids therein, the tear strength by the Elmendorf tear method is usually small. The tear strength of the porous resin sheet by the Elmendorf tear method is, for example, 0.2 N or less, and may be 0.15 N or less. The Elmendorf tear method (JIS K7128-2) can be used for the tear strength measurement. A laminate in which 16 sheets are laminated is used as a test piece, and the shape of the test piece is 75 mm × 63 mm.

  Although the thickness of a porous resin sheet is not specifically limited, For example, they are 30 micrometers or more and 90 micrometers or less, and it is preferable that they are 40 micrometers or more and 80 micrometers or less. Further, the porous resin sheet may have a single layer structure or a multilayer structure. When the porous resin sheet has a multilayer structure, the resin component contained in each layer may be the same or different. As an example of a porous resin sheet having a multi-layer structure, an inner layer and two outer layers arranged on both sides of the inner layer, the resin components contained in the two outer layers are the same, and the resin contained in the outer layer Examples thereof include porous resin sheets in which the component and the resin component contained in the inner layer are different.

  The porous resin sheet preferably has a high visible light reflectance. Specifically, the minimum reflectance in the visible region is preferably 70% or more, more preferably 75% or more, and further preferably 80% or more. The minimum reflectance in the visible region is 450 nm or more and 750 nm in the visible region at an incident angle of 8 ° using an ultraviolet / visible / near infrared spectrophotometer (Shimadzu UV-3600) and an integrating sphere attachment device (ISR-3100). It can obtain | require by measuring the reflectance (total reflectance) in the following.

  The smoothness of the porous resin sheet is preferably high. Specifically, the arithmetic average height Sa on the surface of the porous resin sheet is, for example, 1 μm or less, preferably 0.7 μm or less, and more preferably 0.5 μm or less. The antifouling property of the porous resin sheet is preferably high. Specifically, the contamination grade (JIS-L-1919) on the surface of the porous resin sheet is preferably 3 or more, and more preferably 3.5 or more.

It is preferable that the porous resin sheet has all of moisture permeability, air permeability, and water impermeability. Moisture permeability refers to the property of allowing water, i.e., water vapor, to pass through, and air permeability refers to the property of allowing gas, such as carbon dioxide, to pass. A property that is not allowed. The moisture permeability of the porous resin sheet is, for example, 600 g / m ² · day or more, preferably 700 g / m ² · day or more, and more preferably 800 g / m ² · day or more. The water pressure resistance of the porous resin sheet is, for example, 10 kPa or more, and preferably 20 kPa or more. The opacity of the porous resin sheet is preferably 70% or more and 100% or less, for example. The opacity of the porous resin sheet is based on JIS Z 8722. The density of the porous resin sheet is, for example, 0.50 g / cm ³ or more and 0.90 g / cm ³ or less, and preferably 0.50 g / cm ³ or more and 0.70 g / cm ³ or less.

  The manufacturing method of a porous resin sheet will not be specifically limited if it is a method by which a desired porous resin sheet is obtained, A well-known manufacturing method is employable. Moreover, it is preferable that the porous resin sheet has been subjected to stretching treatment.

2. Reinforcing sheet A reinforcing sheet is a sheet which is arrange | positioned at the one surface side of the said porous resin sheet, and reinforces the said porous resin sheet.

  The reinforcing sheet preferably contains a resin. The resin may be a thermoplastic resin or a thermosetting resin, but the former is preferred. The resin is the same as that described in “(1) Resin”. In particular, the resin contained in the reinforcing sheet is preferably a polyolefin resin. This is because heat resistance, water resistance, chemical resistance and cost are excellent. The polyolefin resin may be, for example, a polyethylene resin or a polypropylene resin.

  Moreover, it is preferable that both the reinforcing sheet and the porous resin sheet are polyolefin resin sheets containing a polyolefin resin as a resin. For example, when an adhesive layer to be described later is provided, the polyolefin-based resin has the same adhesiveness to the adhesive, and thus a strongly adhered agricultural sheet can be obtained. Further, since the degree of expansion and contraction due to heat, moisture, and the like is close, warpage is unlikely to occur and adhesion is difficult to peel off. As a result, an agricultural sheet with high durability is obtained. Moreover, since polyolefin resin is used, it becomes an agricultural sheet | seat with high water resistance.

  Moreover, it is preferable that a reinforcement sheet contains a polyethylene-type resin as a main component, and a porous resin sheet contains a polypropylene-type resin as a main component. This is because the processability of agricultural sheets is improved. Specifically, since a polypropylene resin is a relatively hard resin, it is difficult to process. On the other hand, since the polyethylene resin is a relatively soft resin, the processability of the agricultural sheet is improved by combining the polypropylene resin and the polyethylene resin.

  The reinforcing sheet preferably has a high ultraviolet reflectance. The average reflectance of ultraviolet rays (wavelength of 300 nm or more and 380 nm or less) of the reinforcing sheet is, for example, 35% or more, preferably 60% or more, and more preferably 80% or more. The measurement conditions for the average reflectance of ultraviolet rays will be described in detail in Examples.

  In the agricultural sheet 10, one reinforcing sheet may be used, or two or more reinforcing sheets may be used. As an agricultural sheet having one reinforcing sheet, for example, as shown in FIG. 2, a porous resin sheet 1, a reinforcing sheet 2, and an adhesive layer 3 disposed between the porous resin sheet 1 and the reinforcing sheet 2. An agricultural sheet 10 having

  On the other hand, as an agricultural sheet having two or more reinforcing sheets, for example, as shown in FIG. 3, the porous resin sheet 1, the two reinforcing sheets 2, and the porous resin sheet 1 and the reinforcing sheet 2 are arranged. The agricultural sheet | seat 10 which has the made adhesion layer 3 is mentioned. The two reinforcing sheets 2 include a first reinforcing sheet 2a, a second reinforcing sheet 2b, and an adhesive layer 3 disposed between the first reinforcing sheet 2a and the second reinforcing sheet 2b. Although not shown, the plurality of reinforcing sheets may be directly laminated without using an adhesive layer.

  Moreover, when there are two or more reinforcing sheets, at least one reinforcing sheet may be a porous sheet. In that case, it is preferable that the porosity of a porous sheet exists in the range mentioned above. Moreover, it is preferable that a porous sheet is a reinforcement sheet furthest away from the porous resin sheet. This is because the degree of expansion and contraction due to heat, moisture, and the like is close, and sandwiching between sheets having a porous structure makes it difficult for warpage to occur and adhesion is difficult to peel off.

  Although the thickness of a reinforcement sheet is not specifically limited, For example, they are 10 micrometers or more and 150 micrometers or less, and it is preferable that they are 20 micrometers or more and 100 micrometers or less. In addition, when a reinforcement sheet is a multilayer structure, it is preferable that the thickness of each layer which comprises a reinforcement sheet exists in the range mentioned above. Moreover, the reinforcing sheet may be arrange | positioned at the outermost surface of the agricultural sheet | seat, and may be arrange | positioned inside.

  The tear strength of the reinforcing sheet by the Elmendorf tear method is, for example, 2.8 N or more, 3.0 N or more, or 3.5 N or more. On the other hand, the tear strength of the reinforcing sheet is, for example, 10 N or less. When the reinforcing sheet has a multilayer structure, the tear strength of the entire reinforcing sheet may be equal to or higher than the specific value described above, but at least one layer constituting the reinforcing sheet is equal to or higher than the specific value described above. Is preferred.

The reinforcing sheet may have higher moisture permeability than the porous resin sheet. The moisture permeability of the reinforcing sheet is preferably 8 times or more than the moisture permeability of the porous resin sheet, for example. Moisture permeability of the reinforcing sheet is, for example, 5000g ^/ m 2 · day or more, preferably 6000g ^/ m 2 · day or more.

3. Adhesive layer In the agricultural sheet of the present disclosure, the porous resin sheet and the reinforcing sheet may be laminated via an adhesive layer, or may be laminated directly without using an adhesive layer. The adhesive layer is made of an adhesive material. The adhesive is not particularly limited, but is preferably a dry laminate adhesive.

  The type of adhesive is not particularly limited. For example, polyether adhesive, polyester adhesive, polyurethane adhesive, vinyl adhesive, (meth) acrylic adhesive, polyamide adhesive, epoxy adhesive Materials, rubber adhesives and the like. The adhesive may be a one-component curable type or a two-component curable type.

  Examples of the polyether adhesive include polyether polyurethane. Polyether polyurethane is obtained by the reaction of polyether polyol and polyisocyanate. Examples of the polyether polyol include a compound obtained by polymerizing an oxirane compound such as ethylene oxide or propylene oxide using a polyhydric alcohol such as ethylene glycol, 1,2-propanediol, or glycerin as a polymerization initiator.

  Examples of the polyisocyanate include 1,6-hexamethylene diisocyanate, methylene diisocyanate, trimethylene diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 2,4,4-trimethylhexamethylene diisocyanate, tetramethylene diisocyanate, 1, Aliphatic isocyanates such as 2-propylene diisocyanate, isopropylene diisocyanate and 1,3-butylene diisocyanate; 1,3-cyclohexane diisocyanate, 1,4-cyclohexane diisocyanate, isophorone diisocyanate, 1,3-bis (isocyanatomethyl) cyclohexane, methyl -Alicyclic isocyanates such as 2,6-cyclohexane diisocyanate; m-phenylene diisocyanate, p- E D diisocyanate, 4,4-diphenylmethane diisocyanate, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, aromatic isocyanates such as naphthylene diisocyanate and the like.

  Examples of the polyester adhesive include polyester polyurethane. Polyester polyurethane is obtained by the reaction between polyester polyol and polyisocyanate. Examples of the polyester polyol include a polyester polyol obtained by reacting a polyvalent carboxylic acid and a polyhydric alcohol, and a polyester polyol obtained by ring-opening polymerization of a lactone ring. Examples of the polyvalent carboxylic acid include saturated aliphatic polyvalent carboxylic acids such as adipic acid, azelaic acid, succinic acid, and sebacic acid; unsaturated aliphatic polyvalent carboxylic acids such as fumaric acid and maleic acid; 1,4- Examples thereof include alicyclic polycarboxylic acids such as cyclohexanedicarboxylic acid; aromatic polycarboxylic acids such as phthalic acid, isophthalic acid and terephthalic acid.

  Examples of the polyhydric alcohol include aliphatic and alicyclic polyhydric alcohols, and aromatic polyhydric alcohols. Specifically, ethylene glycol, diethylene glycol, 1,3-propylene glycol, dipropylene glycol, neopentyl glycol, triethylene glycol, xylylene glycol, polyethylene glycol, 1,2-propanediol, 1,3-propanediol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,5-pentanediol and the like can be mentioned. The polyisocyanate is as described above.

  Moreover, you may use polyether polyester polyurethane as an adhesive material. The polyether polyester polyurethane is a polyether adhesive and a polyester adhesive. The polyether polyester polyurethane is obtained by reacting a polyether ester polyol with a polyisocyanate. As polyether ester polyol, the polyether ester polyol obtained by making said polyhydric carboxylic acid react with the said polyether polyol is mentioned, for example.

  The thickness of the adhesive layer is not particularly limited, but is preferably thinner from the viewpoint of ensuring moisture permeability. The thickness of the adhesive layer is, for example, 10 μm or less.

4). Agricultural Sheet The agricultural sheet of the present disclosure includes the porous resin sheet and the reinforcing sheet described above. Agricultural sheets have high UV reflectance. The average reflectance of ultraviolet rays (wavelength of 300 nm or more and 380 nm or less) on the surface of the agricultural sheet on the reinforcing sheet side is usually 35% or more, preferably 60% or more, and more preferably 80% or more. The measurement conditions for the average reflectance of ultraviolet rays will be described in detail in Examples.

  Moreover, the agricultural sheet of this indication has a high visible light reflectance. The average reflectance of visible light (wavelength of 380 nm or more and 780 nm or less) is usually 70% or more, preferably 80% or more, and more preferably 90% or more. The measurement conditions for the average reflectance of visible light will be described in detail in Examples.

Further, the average reflectance of the ultraviolet (or wavelength 300 nm 380nm or less) in the plane of the reinforcing sheet side and _{R U,} the average reflectance of visible light (wavelength 380nm or 780nm or less) and _{R V,} infrared (wavelength 780nm or 1050nm or less the average reflectance) and _{R I.} R _U / R _I is, for example, 0.4 or more and 1.0 or less, and preferably 0.8 or more and 1.0 or less. R _V / R _I is, for example, 1.1 or more and 2.3 or less. In addition, the average reflectance of ultraviolet rays, visible light, and infrared rays (average reflectance at a wavelength of 300 nm to 1050 nm) can be expressed by (R _U + R _V + R _I ) / 3. (R _U + R _V + R _I ) / 3 is, for example, 60% or more, preferably 70% or more, more preferably 80% or more, and further preferably 90% or more.

  The agricultural sheet may or may not have a light reflecting layer. When providing a light reflection layer, visible light reflectance can be made higher, and coloring of fruit can be accelerated | stimulated or the raise of ground temperature can be suppressed. The light reflecting layer contains, for example, a white powder and a resin component. Examples of the white powder include anatase type or rutile type titanium oxide, titanium oxide whose surface is treated with a metal oxide such as Al, Si, calcium carbonate, barium sulfate, and the like. Examples of the resin component include polyurethane resins and polyester resins. Examples of the polyurethane resin include polyester polyurethane, polyether polyurethane, polyether polyester polyurethane, polycarbonate polyurethane, and polycaprolactam polyurethane. The arrangement location of the light reflecting layer is not particularly limited, and may be the outermost surface of the agricultural sheet or may be inside. Moreover, it is preferable that the light reflection layer is provided on the side opposite to the reinforcing sheet with reference to the porous resin sheet. The thickness of the light reflection layer is, for example, not less than 0.5 μm and not more than 4 μm.

  The agricultural sheet preferably has a high tear strength by the Elmendorf tear method. It is because it can suppress that the edge part of an opening tears when forming an opening in an agricultural sheet | seat. The tear strength of the agricultural sheet by the Elmendorf tear method is, for example, 1.4N or more, and preferably 2.5N or more. On the other hand, the tear strength of the agricultural sheet is, for example, 15N or less, and may be 10N or less.

Although the thickness of an agricultural sheet is not specifically limited, For example, they are 50 micrometers or more and 200 micrometers or less, and it is preferable that they are 80 micrometers or more and 150 micrometers or less. The moisture permeability of the agricultural sheet may be, for example, 600 g / m ² · day or more, or 650 g / m ² · day or more. The agricultural sheet may have a plurality of through holes penetrating from one surface to the other surface. The rate of the through holes is, for example, 10,000 pieces / m ² or more and 1,000,000 pieces / m ² , and preferably 100,000 pieces / m ² or more and 700,000 pieces / m ² or less. Moreover, although the installation method of an agricultural sheet is not specifically limited, It is preferable to install so that the surface at the side of the reinforcement sheet of an agricultural sheet may be exposed.

5. Agricultural sheet manufacturing method The manufacturing method of the agricultural sheet of the present disclosure is not particularly limited as long as the target agricultural sheet is obtained. For example, a porous resin sheet and a reinforcing sheet are bonded via an adhesive layer. The method, the method of heat-sealing a porous resin sheet and a reinforcement sheet are mentioned.

  FIG. 4 is a schematic cross-sectional view showing an example of a method for manufacturing an agricultural sheet, and specifically shows a method for manufacturing an agricultural sheet by a dry laminating method. In FIG. 4, the adhesive composition 3x containing an adhesive and a solvent is applied to the surface of the porous resin sheet 1 (FIG. 4 (a)). Next, the solvent is removed by drying the adhesive composition 3x to form the adhesive layer 3 (FIG. 4B). Next, the porous resin sheet 1 and the reinforcing sheet 2 are laminated via the adhesive layer 3 (FIG. 4C). Thereby, the agricultural sheet | seat 10 with which the porous resin sheet 1, the contact bonding layer 3, and the reinforcement sheet 2 are arrange | positioned in this order is obtained (FIG.4 (d)). In the case of using the dry laminating method, since the voids of the porous resin sheet are not crushed, there is an advantage that a decrease in moisture permeability can be suppressed.

  The adhesive composition contains at least an adhesive and a solvent. The adhesive is as described above. On the other hand, examples of the solvent include alcohols such as isopropyl alcohol and normal propyl alcohol, esters such as methyl acetate, ethyl acetate, butyl acetate, propyl acetate, ethyl lactate, and ethylene glycol acetate, ketones such as methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone. , Ethers such as diethylene glycol methyl ether, tetrahydrofuran and dioxane, aromatics such as toluene and xylene, and halogenated hydrocarbons.

  Examples of the method for applying the adhesive composition include general coating methods such as roll coating, gravure coating, kiss coating, knife coating, dip coating, and spray coating. Although the temperature which dries the said adhesive composition changes also with the kind of porous resin sheet and solvent, it is 90 degrees C or less, for example, and it is preferable that it is 70 degrees C or less. Further, vacuum drying such as vacuum drying may be performed. The drying time is appropriately selected according to the type of adhesive.

  For example, when laminating the porous resin sheet 1 and the reinforcing sheet 2 by roll to roll, it is preferable to control the pressure by tension. In this case, for example, it is preferable to manage the first paper-feeding porous resin sheet from 50 N to 110 N, and more preferably from 80 N to 100 N. In order to prevent curling of the entire film, the reinforcing sheet for the second paper feed is preferably managed, for example, from 20N to 50N, and more preferably from 30N to 40N. In the dry laminating method, the lamination is usually performed in a temperature environment where the voids of the porous resin sheet do not change. In addition, although it is not necessary to heat at the time of lamination | stacking, you may heat if it is the temperature which the space | gap of a porous resin sheet does not change.

  In addition, this indication is not limited to the said embodiment. The above-described embodiment is an exemplification, and the technical idea described in the claims of the present disclosure has substantially the same configuration and exhibits the same function and effect in any case. It is included in the technical scope of the disclosure.

[Example 1]
(Preparation of porous resin sheet)
As a resin composition constituting the inner layer of the porous resin sheet, a propylene homopolymer (manufactured by Nippon Polychem Co., Ltd., trade name “Novatech PP: MA-8”, melting point 164 ° C.) is 65.5% by mass, high density Calcium carbonate powder having 6.5% by mass of polyethylene (manufactured by Nippon Polychem Co., Ltd., trade name “Novatech HD: HJ580”, melting point 134 ° C., density 0.960 g / cm ³ ) and an average particle size of 1.5 μm An unstretched sheet was obtained from the resin composition comprising 28% by mass using an extruder. Next, this unstretched sheet was stretched 4 times in the longitudinal direction to obtain a uniaxially stretched sheet.

  On the other hand, as a resin composition constituting the outer layer of the porous resin sheet, 51.5% by mass of a propylene homopolymer, 3.5% by mass of high-density polyethylene, and an average particle diameter of 1 are the same as described above. A resin composition comprising 42% by mass of calcium carbonate powder of 5 μm and 3% by mass of titanium oxide powder having an average particle diameter of 0.8 μm was melt-kneaded using another extruder, and the uniaxially stretched sheet of the above-mentioned A laminated sheet having an outer layer, an inner layer, and an outer layer was obtained by extruding from both sides of the surface through a die.

  Next, this laminated sheet is stretched 7 times in the transverse direction and slits at the ears, so that the thickness is 70 μm, and the outer layer (15 μm), inner layer (40 μm), outer layer (15 μm) have a layer structure, A porous resin sheet containing voids was obtained. The porosity of the obtained porous resin sheet was 55%, and the opacity was 93%.

(Production of agricultural sheet)
An L-LDPE film (linear low-density polyethylene film, 30 μm thick, TUX TC-S, manufactured by Mitsui Chemicals, Inc.) is prepared as a reinforcing sheet, and the reinforcing sheet and porous resin sheet are joined by the dry lamination method. did. Specifically, Takelac A-969V (polyol component) and Takenate A-5 (isocyanate component) were used as polyether adhesives. The polyether-based adhesive was applied and bonded under the conditions of a drying temperature of 70 ° C. and 2 g / m ² . In this way, an agricultural sheet was obtained.

[Example 2]
An agricultural sheet was obtained in the same manner as in Example 1 except that an L-LDPE film (linear low-density polyethylene film, thickness 40 μm, TUX TC-S, manufactured by Mitsui Chemicals, Inc.) was used as the reinforcing sheet. .

[Example 3]
A second reinforcing sheet was bonded onto the agricultural sheet L-LDPE film obtained in Example 1. As a second reinforcing sheet, a porous polyethylene sheet (thickness 30 μm, YP5000, manufactured by Yamatogawa Polymer Co., Ltd.) was prepared and joined by a dry laminating method. Specifically, Takelac A-969V (polyol component) and Takenate A-5 (isocyanate component) were used as polyether adhesives. The polyether-based adhesive was applied and bonded under the conditions of a drying temperature of 70 ° C. and 2 g / m ² . In this way, an agricultural sheet was obtained.

[Example 4]
An agricultural sheet was obtained in the same manner as in Example 1 except that a porous polyethylene sheet (thickness 30 μm, YP5000, manufactured by Yamatogawa Polymer Co., Ltd.) was used as the reinforcing sheet.

[Comparative Example 1]
As Comparative Example 1, an agricultural sheet having a single layer structure was prepared. Specifically, as Comparative Example 1, a black and white multi-film (thickness 20 μm, twin white, manufactured by Sekisui Film Co., Ltd.) was prepared.

[Evaluation]
Reflectivity measurement (ultraviolet region, visible region, and infrared region) was performed on the agricultural sheets obtained in Examples 1 to 4 and Comparative Example 1.

In the reflectance measurement, reflection in a wavelength region of 300 nm or more and 1050 nm or less at an incident angle of 8 ° using an ultraviolet / visible / near infrared spectrophotometer (Shimadzu Corporation UV-3600) and an integrating sphere attached device (ISR-3100). The ratio (total reflectance) was measured, and the average reflectances in the ultraviolet region (300 nm to 380 nm or less), the visible region (380 nm to 780 nm or less), and the infrared region (780 nm to 1050 nm or less) were determined. As the standard plate, Spectralon (manufactured by Teflon (registered trademark)) manufactured by Labsphere, USA was used. The measurement surface was the surface of the agricultural sheet on the side of the reinforcing sheet (opposite to the porous resin sheet). The average reflectance of the ultraviolet to the average reflectance of the infrared _{(R I) (R U)} ratio of _(R U _/ R I), and the average reflectance of visible light to the average reflectance of the infrared _{(R I)} ( The ratio of R _V ) (R _V / R _I ) was calculated. These results are shown in Table 1 and FIG.

As shown in Table 1 and FIG. 5, Examples 1 to 4 showed better values for ultraviolet reflectance and visible light reflectance than Comparative Example 1. In particular, Examples 2 and 3 were confirmed to have a high insect repellent effect because of their high ultraviolet reflectance. Further, Examples _1-4, the values of R U / _{R I,} the value of R U / _{R I,} has a value of _{(R U + R V + R} I) / 3 is in a predetermined range, good UV reflectivity and Good infrared reflectance was shown. In addition, although the agricultural sheet | seat obtained in the comparative example 1 is a sheet | seat obtained by extrusion molding, the quantity of the white material mix | blended with base resin has an upper limit from balance with intensity | strength, and visible light reflectance is enough. It was suggested that it cannot be increased.

DESCRIPTION OF SYMBOLS 1 ... Porous resin sheet 2 ... Reinforcement sheet 3 ... Adhesive layer 10 ... Agricultural sheet

Claims (5)

A porous resin sheet having a plurality of voids therein;
A reinforcing sheet disposed on one side of the porous resin sheet;
Have
The agricultural sheet whose average reflectance of the ultraviolet-ray (wavelength 300nm or more and 380nm or less) in the surface at the side of the said reinforcement sheet is 35% or more. UV in the plane of the reinforcing sheet side average reflectance (minimum wavelength 300 nm 380 nm or less) and _{R U,} the average reflectance of visible light (wavelength equal to or more than 380 nm 780nm or less) and _{R V,} infrared (wavelength 780nm or 1050nm or less) When the average reflectance of R is _I ,
R _U / R _I is 0.4 or more and 1 or less,
R _V / R _I is 1.1 or more and 2.3 or less,
The agricultural sheet according to claim 1, wherein (R _U + R _V + R _I ) / 3 is 60% or more. A porous resin sheet having a plurality of voids therein;
A reinforcing sheet disposed on one side of the porous resin sheet;
Have
UV in the plane of the reinforcing sheet side average reflectance (minimum wavelength 300 nm 380 nm or less) and _{R U,} the average reflectance of visible light (wavelength equal to or more than 380 nm 780nm or less) and _{R V,} infrared (wavelength 780nm or 1050nm or less) When the average reflectance of R is _I ,
R _U / R _I is 0.4 or more and 1 or less,
R _V / R _I is 1.1 or more and 2.3 or less,
An agricultural sheet in which (R _U + R _V + R _I ) / 3 is 60% or more.   The agricultural sheet according to any one of claims 1 to 3, comprising two or more reinforcing sheets.   The agricultural sheet according to claim 4, wherein the reinforcing sheet farthest from the porous resin sheet among the two or more reinforcing sheets has a porous structure in which a plurality of voids are present.