JP4757657B2 - Agricultural coating for leek cultivation - Google Patents

Description

  The present invention relates to an agricultural covering material that can be suitably used for leek cultivation, and more particularly, to an agricultural covering material for leek cultivation having ultraviolet shielding, heat shielding performance, and light transmittance suitable for leek cultivation. .

  Conventionally, agricultural covering materials such as polyolefin resin films and polyvinyl chloride resin films have been used for houses and tunnels in cultivation facilities for leek cultivation. For example, JP-A-8-308377 (Patent Document 1) , Substantially does not transmit light having a wavelength of 360 nm or less, has a transmittance of 15 to 40% for light having a wavelength of 380 nm, substantially transmits light having a wavelength of 400 nm or more, and transmits infrared light having a wavelength range of 4 to 25 μm. An agricultural synthetic resin coating material having an average transmittance of 40% or less is disclosed.

  However, such an agricultural synthetic resin coating material is effective in keeping the nighttime heat in the cold season in order to prevent the radiation of far-infrared rays from the house at night in the cold season. Due to the irradiation, the temperature in the house was about 40 ° C., and there was a problem that the growth of leek due to an overheated state was hindered.

  In order to prevent such an overheated state, the sun's irradiation is shielded by coating another coating material such as a net on the agricultural coating material, or a white pigment such as titanium oxide is added to the coating material. For this reason, agricultural covering materials with reduced light transmission are used.

  For example, in Japanese Patent Application Laid-Open No. 61-111350 (Patent Document 2), a light shielding property for agriculture comprising a vinyl chloride resin and an aluminum powder, a white pigment (titanium oxide) or a white pigment, and carbon black. A dressing is disclosed. In JP 2004-314363 A (Patent Document 3), a polyethylene multilayer comprising at least one white resin layer containing 100 parts by mass of a polyethylene resin and 10 to 50 parts by mass of a titanium oxide pigment. Agricultural coating material which is a film, has 10 to 50 parts by mass of titanium oxide pigment with respect to 100 parts by mass of polyethylene resin in the entire multilayer film, has a thickness of 70 to 200 μm, and a light shielding rate of 80% or more is disclosed. Has been. However, in the agricultural coating materials described in Patent Documents 2 to 3, in order to efficiently shield sunlight from the titanium oxide to be contained, the weight average particle diameter is generally about 500 nm or less (preferably 100 nm to 300 nm). Particle size titanium oxide was used. Therefore, even if a small amount of titanium oxide pigment is contained, the agricultural coating itself becomes white and the appearance and transparency are impaired, and the average transmittance of light in the visible light region necessary for photosynthesis is lowered and There has been a problem of affecting the development of

In Japanese Patent Application Laid-Open No. 11-292996 (Patent Document 4), a metal in which another metal having an oxidation number equal to or lower than the oxidation number of the metal constituting the metal oxide is dissolved in the crystal structure of the metal oxide. A thermoplastic resin film comprising a substance obtained by coating an oxide with a titanium oxide or a hydrous oxide is disclosed. However, in the thermoplastic resin film described in Patent Document 3, titanium oxide having a fine particle diameter of 1 to 500 nm is used, and thus the problem that transparency is impaired and the visibility necessary for photosynthesis are required. There was a problem that even the light in the light region was largely blocked, affecting the cultivation of crops.
JP-A-8-308377 Japanese Patent Laid-Open No. 61-111350 JP 2004-314363 A Japanese Patent Laid-Open No. 11-292996

  This invention is made | formed in view of the subject which the said prior art has, and it is an agricultural coating | covering material provided with the thermoplastic resin film containing a titanium oxide while having the ultraviolet shielding property suitable for leek cultivation. Regardless, it is possible to sufficiently transmit light having a wavelength in the visible light region without excessively transmitting light having a wavelength in the near-infrared light region, and to have sufficient transparency and excellent heat shielding properties. It aims at providing the agricultural covering material for leek cultivation which can have.

  As a result of intensive studies to achieve the above object, the inventors of the present invention have applied a titanium oxide having a weight average particle diameter of 0.6 to 1.5 μm as a thermoplastic resin 100 mass in an agricultural covering material for leek cultivation. By providing at least one layer of a thermoplastic resin film containing 0.2 to 0.7 parts by mass with respect to the part, the wavelength surprisingly has a wavelength without excessively transmitting light in the near infrared light region. Has been found to be able to sufficiently transmit light in the visible light region, and to have sufficient transparency and excellent heat shielding properties, and has completed the present invention.

  That is, the agricultural covering material for leek cultivation of the present invention is an agricultural covering material for leek cultivation comprising at least one layer of thermoplastic resin film, and at least one layer of the thermoplastic resin film has a weight average particle diameter. Containing 0.2 to 0.7 parts by mass of titanium oxide having a ratio of 0.6 to 1.5 μm with respect to 100 parts by mass of the thermoplastic resin, and 0.1 wt% of the ultraviolet absorber with respect to 100 parts by mass of the thermoplastic resin. -2.0 mass part is contained, It is characterized by the above-mentioned.

  Moreover, as the agricultural covering material for leek cultivation of the present invention, the transmittance of light in the ultraviolet region having a wavelength of less than 380 nm is less than 5%, and the average transmittance of light in the ultraviolet region of 380 or more and less than 400 nm is 15%. The average transmittance of light rays in the visible light region of 400 nm or more and less than 700 nm is 75% or more, and the average transmittance of light rays in the near-infrared light region of wavelength 700 nm or more and less than 2000 nm is 85%. The following is preferable.

  Furthermore, as the agricultural covering material for leek cultivation of the present invention, the direct light transmittance of transmitted light having a wavelength of 700 nm or more and less than 2000 nm is preferably 40 to 75%.

  In the summertime when the amount of sun's light irradiation is large, it is possible to improve the heat insulation performance by using double the agricultural covering material for leek cultivation of the present invention, while in the wintertime when cooling at night is severe In order to increase the heat retention, it may be partially used twice.

  According to the present invention, the wavelength is not excessively transmitted through the light having a wavelength in the near-infrared light region, even though it is an agricultural covering material for leek cultivation provided with a thermoplastic resin film containing titanium oxide. It becomes possible to provide an agricultural covering material for leek cultivation that can sufficiently transmit light rays in the visible light region and that has sufficient transparency and excellent heat shielding properties.

  In addition, the combined use of titanium oxide and an ultraviolet absorber also has the effect of reflecting light in the ultraviolet region of titanium oxide itself, so that it is possible to further block light transmission in the ultraviolet region, and the wavelength is 380 nm. The transmittance of light in the ultraviolet region of less than 5% is less than 5%, and the average transmittance of light in the ultraviolet region of 380 to less than 400 nm is 15% or less. Therefore, the occurrence of diseases can be suppressed, the average transmittance of light in the visible light region of 400 nm or more and less than 700 nm is 75% or more, and the wavelength is 700 nm or more and 2000 nm. Since the average transmittance of light rays in the near-infrared light region of less than 85% is less than or equal to 85%, the effect of blocking the light rays in the near-infrared light region sufficiently through the visible light region To, it is possible to suppress the growth inhibition of leek due to over temperature fault.

  Furthermore, since the direct light transmittance of the transmitted light in the near-infrared light region is 40 to 75%, the direct irradiation of the light to the leek is moderated. It is possible to prevent the appearance from being deteriorated due to the twisting of itself, and to improve the harvesting rate. The direct light in the present invention is a light beam that linearly passes through the coating material, and the direct light transmittance is a thing that indicates the ratio of the light beam that is transmitted as direct light among the transmitted light beams. is there.

  Hereinafter, the present invention will be described in detail with reference to preferred embodiments thereof.

  The agricultural covering material for leek cultivation of the present invention is an agricultural covering material for leek cultivation provided with at least one layer of thermoplastic resin film, and at least one layer of the thermoplastic resin film has a weight average particle size of 0. 0.2 to 0.7 parts by mass of titanium oxide having a diameter of 6 to 1.5 μm with respect to 100 parts by mass of the thermoplastic resin, and 0.1 to 2 parts of the ultraviolet absorber with respect to 100 parts by mass of the thermoplastic resin. It is characterized by containing 0.0 part by mass.

  The titanium oxide used in the present invention has a weight average particle diameter of 0.6 to 1.5 μm. When the weight average particle diameter is less than 0.6 μm, the average transmittance of light in the visible light region having a wavelength of 400 nm or more and less than 700 nm is lowered, and the average transmittance of light in the near infrared light region having a wavelength of 700 nm or more and less than 2000 nm. As the resulting agricultural covering material for leek cultivation becomes white and the transparency decreases, the efficiency of photosynthesis of leek in the house covered with the agricultural covering material decreases, and also the heat shielding property descend. On the other hand, when the weight average particle diameter exceeds 1.5 μm, the light scattering efficiency in the near-infrared region decreases, and as a result, the average transmittance of light in the near-infrared light region increases and the heat shielding property decreases, The dispersibility with respect to a thermoplastic resin falls, and the possibility that the moldability as a uniform film will fall becomes high.

  At least one layer of the thermoplastic resin film according to the present invention comprises 0.2 to 0.7 parts by mass of titanium oxide having a weight average particle diameter of 0.6 to 1.5 μm with respect to 100 parts by mass of the thermoplastic resin. It is contained. In such a thermoplastic resin film containing titanium oxide according to the present invention, when the titanium oxide content is less than 0.2 parts by mass, the average transmission of light rays in the near-infrared region where the wavelength is 700 nm or more and less than 2000 nm. On the other hand, when the ratio exceeds 85%, and the ratio exceeds 0.7 parts by mass, the average transmittance of light in the visible light region having a wavelength of 400 nm or more and less than 700 nm is less than 75%.

  As an ultraviolet absorber used for this invention, if it is used as a normal agricultural coating | covering agent, it can be used. For example, salicylic acid ester, benzotriazole, hydroxybenzophenone, acrylonitrile substitution product and the like can be mentioned. Such an ultraviolet absorber can be used individually by 1 type or in mixture of 2 or more types. Specifically, 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-ethoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 5,5′-methylenebis (2-hydroxy 2-hydroxybenzophenones such as -4-methoxybenzophenone); 2- (2′-hydroxy-5′-methylphenyl) benzotriazole, 2- (2′-hydroxy-3 ′, 5′-di-tert-butyl) Phenyl) -5-chlorobenzotriazole, 2- (2′-hydroxy-3′-tert-butyl-5′-methylphenyl) -5-chlorobenzotriazole, 2- (2′-hydroxy-5′-tert-) Octylphenyl) benzotriazole, 2- (2′-hydroxy-3 ′, 5′- 2- (2′-hydroxyphenyl) benzotriazoles such as cumylphenyl) benzotriazole, 2,2′-methylenebis (4-tert-octyl-6-benzotriazole) phenol; phenyl salicylate, resorcinol monobenzoate, 2, Benzoates such as 4-di-tert-butylphenyl-3 ′, 5′-di-tert-butyl-4′-hydroxybenzoate, hexadecyl-3,5-di-tert-butyl-4-hydroxybenzoate; Oxanilides such as ethoxy-4'-dodecyloxanilide; Cyanoacrylates such as ethyl-α-cyano-β, β-diphenylacrylate, methyl-2-cyano-3-methyl-3- (p-methoxyphenyl) acrylate Kind.

  The addition amount of the ultraviolet absorber is 0.1 to 2.0 parts by mass with respect to 100 parts by mass of the thermoplastic resin. However, in the present invention, titanium oxide used in combination is added because it has ultraviolet absorption performance. The ultraviolet absorber can obtain a sufficient effect in a smaller amount than the addition amount for obtaining the desired performance, and in the addition amount, the transmittance of light in the ultraviolet region having a wavelength of less than 380 nm is less than 5%, It is possible to obtain an effect that the average transmittance of light in the ultraviolet region of 380 or more and less than 400 nm is 15% or less.

  Examples of the thermoplastic resin according to the present invention include vinyl chloride resin, olefin resin, ethylene-vinyl acetate copolymer resin, polyester resin, fluorine resin, acrylic resin, and polyurethane resin.

  Examples of the vinyl chloride resin include polyvinyl chloride, which is a homopolymer of vinyl chloride, and vinyl chloride and other monomers, such as ethylene, propylene, vinyl acetate, acrylic acid, methacrylic acid, acrylic ester, methacrylic acid. Examples thereof include copolymers with esters, maleic acid, maleic esters, fumaric acid, itaconic acid, vinylidene chloride, acrylonitrile, higher vinyl ethers, and the like. Such vinyl chloride resins can be used singly or in combination of two or more.

  Examples of the olefin resin include low density polyethylene, linear low density polyethylene, medium density polyethylene, high density polyethylene, polyethylene such as polyethylene polymerized using a metallocene catalyst; random polymerized polypropylene, block polymerized polypropylene, isotactic polypropylene, Examples thereof include polypropylene such as syndiotactic polypropylene; and olefin resins such as ethylene-vinyl acetate, ethylene-acrylic acid, ethylene-acrylic acid ester, ethylene-methacrylic acid, ethylene-methacrylic acid ester, and other ethylene-based copolymers. Such olefin resin can be used individually by 1 type or in mixture of 2 or more types.

  The ethylene-vinyl acetate copolymer (EVA) -based resin is not particularly limited, but those having a vinyl acetate (VA) content of about 5 to 20% by mass can be preferably used. Further, such ethylene-vinyl acetate copolymer resins may be used alone or in combination of two or more different ethylene contents.

  The polyester-based resin is not particularly limited, but polyethylene terephthalate is preferable, and biodegradable aliphatic polyesters, aromatic-aliphatic polyesters, and the like can also be used.

  Further, as the fluororesin, homopolymers or copolymers of ethylene tetrafluoride, ethylene trifluoride chloride, vinylidene fluoride, vinyl fluoride, hexafluoropropylene, perfluorovinyl ether, and other fluorine-containing monomers Alternatively, copolymers of these fluorine-containing monomers and monomers not containing fluorine, such as ethylene-tetrafluoroethylene copolymer and ethylene-trifluorotrifluoroethylene copolymer, can be mentioned. Such a fluorine-type resin can be used individually by 1 type or in mixture of 2 or more types.

  In addition, as the acrylic resin, a homopolymer of a compound such as acrylic acid ester, methacrylic acid ester, acrylic acid, methacrylic acid, acrylamide, acrylonitrile, or a copolymer of the compound, further, the compound and the compound And copolymers with other monomers that can be copolymerized therewith. Such acrylic resins can be used singly or in combination of two or more.

  Furthermore, examples of the polyurethane-based resin include resins having a urethane group in a molecular structure obtained by appropriately reacting a known bifunctional polyol and a known diisocyanate as appropriate as main components. Such polyurethane resins can be used singly or in combination of two or more.

  Moreover, in the range which does not impair the effect of this invention, the said thermoplastic resin can also be used in mixture of 2 or more types.

  In the case where the agricultural covering material for leek cultivation of the present invention has a multilayer structure, it may be a multilayer structure using the same resin of the thermoplastic resin or a multilayer structure of different resins, One layer may have a layer containing titanium oxide and an ultraviolet absorber having a weight average particle diameter of 0.6 to 1.5 μm.

  As a thermoplastic resin film containing the titanium oxide concerning this invention, the film which consists of the above-mentioned thermoplastic resin is mentioned. Among such thermoplastic resin films, the vinyl chloride resin film and the polyolefin resin film are preferable from the viewpoints of processability and durability.

  Further, in the thermoplastic film containing the titanium oxide and the ultraviolet absorber according to the present invention, in addition to the titanium oxide and the thermoplastic resin, a plasticizer, a heat stabilizer, a light stabilizer, an antioxidant, and a lubricant. Various additives such as pigments, fillers, drip-proofing agents and anti-fogging agents can be added.

  As plasticizers, di-2-ethylhexyl phthalate (DOP), di-normal octyl phthalate (n-DOP), diisononyl phthalate (DINP), butyl benzyl phthalate (BBP), diisodecyl phthalate (DIDP), phthalic acid diundecyl ester (DUP) and other typical phthalic acid ester plasticizers, adipic acid dioctyl ester (DOA), sebacic acid dioctyl ester (DOS), azelaic acid dioctyl ester (DOZ) Polymeric plasticizers such as general fatty acid ester plasticizers typified, trimellitic acid ester plasticizers typified by trimellitic acid trioctyl ester (TOTM), polyester plasticizers typified by polypropylene adipate, etc. Other hornets General plasticizers such as acid plasticizers, chlorinated paraffins, tricresyl phosphate (TCP), trixylyl phosphate (TXP), tris (isopropylphenyl) phosphate, tributyl phosphate, triethyl phosphate, triphenyl phosphate, triethyl Phosphate ester plasticizers such as phenyl phosphate, epoxidized products of vegetable oils, and epoxy resins can be used. Examples of epoxidized products of vegetable oils include epoxidized soybean oil and epoxidized linseed oil. Epoxy resins include epoxidized polybutadiene. , Epoxy methyl stearate, butyl epoxy stearate, ethyl hexyl epoxy stearate, tris (epoxypropyl) isocyanurate, 3- (2-xenoxy) -1,2-epoxypropane, bisphenol Lumpur A diglycidyl ether, divinyl cyclohexene diepoxide, epoxy plasticizers such as 2,2-bis (4-hydroxyphenyl) polycondensate of propane and epichlorohydrin. Such plasticizers can be used alone or in combination of two or more. Further, the amount of the plasticizer to be added varies depending on the kind of the plasticizer, but generally 1 to 60 parts by mass is preferable with respect to 100 parts by mass of the thermoplastic resin.

As the heat stabilizer, commonly used heat stabilizers such as metal soaps, organic phosphite stabilizers and β-diketone compounds can be used. Examples of the metal soap include zinc stearate, barium stearate, calcium stearate, barium ricinoleate, calcium laurate, calcium oleate, and zinc octoate. Organic phosphite stabilizers include diphenyl decyl phosphite, triphenyl phosphite, tris (nonylphenyl) phosphite, tridecyl phosphite, tris (2-ethylhexyl) phosphite, tristearyl phosphite, octyl diphenyl phosphite. Fight and so on. Examples of the β-diketone compound include dibenzoylmethane.
Moreover, such a stabilizer can be used individually by 1 type or in mixture of 2 or more types. Moreover, as addition amount of such a stabilizer, 0.5-10 mass parts is preferable with respect to 100 mass parts of thermoplastic resins, More preferably, it is 1-5 mass parts.

  Examples of the light stabilizer include 2,2,6,6-tetramethyl-4-piperidyl stearate, 1,2,2,6,6-pentamethyl-4-piperidyl stearate, 2,2,6,6- Tetramethyl-4-piperidylbenzoate, N- (2,2,6,6-tetramethyl-4-piperidyl) dodecylsuccinimide, 1-[(3,5-di-tert-butyl-4-hydroxyphenyl) Propionyloxyethyl] -2,2,6,6-tetramethyl-4-piperidyl (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, bis (2,2,6,6-tetramethyl- 4-piperidyl) sebacate, bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, bis (1,2,2,6,6, -pentamethyl-4-piperi ) -2-butyl-2- (3,5-di-tert-butyl-4-hydroxybenzyl) malonate, N, N′-bis (2,2,6,6-tetramethyl-4-piperidyl) hexa Methylenediamine, tetra (2,2,6,6-tetramethyl-4-piperidyl) butanetetracarboxylate, bis (2,2,6,6-tetramethyl-4-piperidyl) di (tridecyl) butanetetracarboxylate Bis (1,2,2,6,6-pentamethyl-4-piperidyl) di (tridecyl) butanetetracarboxylate, 3,9-bis {1,1-dimethyl-2- [tris (2,2,6 , 6-Tetramethyl-4-piperidyloxycarbonyloxy) butylcarbonyloxy] ethyl} -2,4,8,10-tetraoxysaspiro [5,5] undeca 3,9-bis {1,1-dimethyl-2- [tris (1,2,2,6,6-pentamethyl-4-piperidyloxycarbonyloxy) butylcarbonyloxy] ethyl} -2,4,8, 10-tetraoxaspiro [5,5] undecane, 1,5,8,12-tetrakis {4,6-bis [N- (2,2,6,6-tetramethyl-4-biperidyl) butylamino]- 1,3,5-triazin-2-yl} -1,5,8,12-tetraazadodecane, 1- (2-hydroxyethyl) -2,2,6,6-tetramethyl-4-piperidinol / succinol Acid dimethyl condensate, 2-tert-octylamino-4,6-dichloro-s-triazine / N, N′-bis (2,2,6,6-tetramethyl-4-piperidyl) hexamethylenediamine condensate, N, N ' And hindered amine light stabilizers such as bis (2,2,6,6-tetramethyl-4-piperidyl) hexamethylenediamine / dibromoethane condensate. Among such hindered amine light stabilizers, hindered amine light stabilizers having an average molecular weight of about 800 to 2000 are preferable. Moreover, it is preferable that it is 0.01-0.3 mass part as an addition amount of such a light stabilizer with respect to 100 mass parts of thermoplastic resins.

  Examples of the antioxidant include alkylphenols, alkylene bisphenols, alkylphenol thioethers, β, β'-thiopropionic acid esters, organic phosphites, aromatic amines, phenol / nickel composites, and the like. Such antioxidant can be used individually by 1 type or in mixture of 2 or more types.

  Examples of the lubricant or the anti-adhesive agent include metal soaps such as zinc stearate, barium stearate, calcium stearate; hydrocarbons such as liquid paraffin, polyethylene waxes, chlorinated hydrocarbons; stearic acid, stearamide, Fatty acids and fatty acid amides such as palmitic acid amide, methylene bisstearamide, ethylene bisstearamide; Fatty acid esters such as butyl stearate, cetyl palmitate, monoglyceride stearate; Fatty acids such as stearic acid, isostearic acid, palmitic acid Lubricants: Lubricants such as organophosphate metal salt lubricants such as barium isodecyl phosphate and calcium octadecyl phosphate can be used. Such lubricants or anti-sticking agents can be used alone or in combination of two or more.

  Examples of the filler include inorganic fillers such as magnesium carbonate, magnesium hydroxide, magnesium silicate, silicon oxide, calcium carbonate, titanium oxide, aluminum hydroxide, aluminum oxide, and talc; acrylic made of a polymer mainly composed of alkyl methacrylate. And organic fillers such as system particles. As such a filler, it is preferable to use a filler having an average particle diameter of 0.5 to 10 μm.

  Examples of the drip-proofing agent include sorbitan fatty acid ester, sorbitol fatty acid ester, glycerin fatty acid ester, diglycerin fatty acid ester, triglycerin fatty acid ester, tetraglycerin fatty acid ester, and the like; sorbitan fatty acid / dibasic acid ester, sorbitol fatty acid -Esters of polyhydric alcohols and fatty acids such as dibasic acid esters, diglycerin fatty acids and dibasic acid esters, esters of polyhydric alcohols and fatty acids and dibasic acids; or ethylene oxide, propylene oxide, butylene oxide, etc. In particular, sorbitan palmitate, sorbitan stearate, sorbitan stearate / ethylene oxide 2 mol adduct, Rubitan stearate / propylene oxide 3 mol adduct, sorbitol stearate, sorbitol stearate / ethylene oxide 3 mol adduct, diglycerin palmitate / ethylene oxide 2 mol adduct, sorbitan stearate adipate / ethylene oxide 2 mol adduct And diglycerin palmitate sebacate / propylene oxide 3 mol adduct, sorbitol palmitate adipate / ethylene oxide 3 mol adduct, and the like. Such drip-proofing agents can be used alone or in combination of two or more. Moreover, as addition amount of such a dripproofing agent, about 0.5-6 mass parts is preferable with respect to 100 mass parts of resin.

Examples of the anti-fogging agent include a fluorine-containing compound having a fluorine-containing group and at least one group selected from a hydroxyl group and an alkylene oxide group in one molecule. Examples of the fluorine-containing group include a perfluoroalkyl group (C _n F _{2n + 1} group), a perfluoroalkoxyl group (C _n F _{2n + 1} O group), a polyfluoroalkyl group (H _m C _n F _{2n + 1-m} group), and perfluoro alkenyl group _{(C n F 2n-1} group), polyfluoroalkenyl group _{(H m C n F 2n-} 1-m group). In the formula of the fluorine-containing group, m represents an integer of 1 to 3, and n represents an integer of 3 to 20. As examples of the alkylene oxide group, the general formula _{(C 2} H 4 _{O) x,} or a group represented by _{(C 3} H 6 _{O) x} and the like. Moreover, x in the said general formula shows the integer of 1-30. The addition amount of such a fluorine-containing compound is preferably 0.01 to 1 part by mass, more preferably about 0.05 to 0.5 part by mass with respect to 100 parts by mass of the thermoplastic resin.

  Other additives include mineral additives such as hydrotalcite and feldspar, and homopolymers and / or copolymers of glycidyl acrylate and / or glycidyl methacrylate. As such a homopolymer and / or copolymer of glycidyl acrylate and / or glycidyl methacrylate, those having an average molecular weight of 1000 or more are preferable. In particular, a homopolymer of glycidyl methacrylate is preferable. The addition amount of the homopolymer and / or copolymer of glycidyl acrylate and / or glycidyl methacrylate is 0.1 to 10 parts by weight, preferably 0.5 to 5 parts by weight with respect to 100 parts by weight of the thermoplastic resin. It is. When the addition amount of the homopolymer and / or copolymer of glycidyl acrylate and / or glycidyl methacrylate is less than the lower limit relative to 100 parts by weight of the thermoplastic resin, no improvement in durability is observed, and there is a tendency to stick when kneaded for a long time. . On the other hand, when the addition amount of the homopolymer and / or copolymer of glycidyl acrylate and / or glycidyl methacrylate with respect to 100 parts by weight of the thermoplastic resin exceeds the above upper limit, the improvement in durability is small for the cost increase, and molding processing Coloring of time tends to occur.

  The method for molding the thermoplastic resin film containing the titanium oxide and the ultraviolet absorber according to the present invention is not particularly limited, and a known molding method such as a calendar method, an extrusion method, an inflation method, or the like can be adopted as appropriate. Further, when an olefin resin is used as the thermoplastic resin, it is preferable to adopt an inflation method from the viewpoints of processability and the width of the product to be obtained (when the width is about 12 m).

  Moreover, the agricultural covering material for leek cultivation of this invention is equipped with at least 1 layer of the thermoplastic resin film containing the titanium oxide whose weight average particle diameter is 0.6-1.5 micrometers, and a ultraviolet absorber. That is, the agricultural covering material for leek cultivation of the present invention may have a single layer structure of a thermoplastic resin film containing the titanium oxide and the ultraviolet absorber, or a thermoplastic resin film containing the titanium oxide and the ultraviolet absorber. May have a multilayer structure including at least one layer.

  Moreover, the agricultural covering material for leek cultivation of the present invention comprising a polyolefin resin comprises at least two thermoplastic resin films, and at least one of the thermoplastic resin films is a polyolefin resin film. An agricultural covering material for leek cultivation is preferred. This is because when a polyolefin resin film is used as the thermoplastic resin film, a multilayer structure is preferable in consideration of processability and physical properties such as a welder.

  Moreover, in the case where the agricultural covering material for leek cultivation of the present invention has a multilayer structure, the type of resin constituting the other layer may be the same as or different from that of the thermoplastic resin film. Furthermore, in the case where the agricultural covering material for leek cultivation of the present invention has a multilayer structure, it is preferable that adjacent layers are layers having high compatibility or adhesiveness. Moreover, as a film which forms such another layer, it is preferable that the average transmittance | permeability of the light ray which has a wavelength in visible region is 70% or more. Moreover, in the film which forms such another layer, the said various additives can be added.

  A method for producing such a multi-layered structure for agricultural cultivation for leek cultivation is not particularly limited, and a known method can be used as appropriate. For example, a multi-layer coextrusion inflation method can be used to form a multilayer at a time. A film having a structure may be manufactured, or a film having a multilayer structure may be manufactured by forming a single layer thermoplastic resin film and then laminating it.

  The thickness of the agricultural covering material for leek cultivation of the present invention is not particularly limited, but is preferably 50 to 200 μm, and more preferably 75 to 150 μm. If the thickness of the agricultural covering material for leek cultivation of the present invention is less than the lower limit, physical properties such as the tensile strength of the agricultural covering material for leek cultivation obtained will tend to be difficult to extend during use, On the other hand, when the above upper limit is exceeded, the obtained litter cultivation covering material for agriculture grows heavy, so that the extension work during use tends to be difficult. In addition, in the case where the agricultural covering material for leek cultivation of the present invention has a multilayer structure, the thermoplastic resin film containing titanium oxide according to the present invention is 50 to 50 from the viewpoint of reliably exhibiting the effects of the present invention. It preferably has a thickness of 150 μm.

  EXAMPLES Hereinafter, although this invention is demonstrated more concretely based on an Example and a comparative example, this invention is not limited to a following example. Moreover, the agricultural covering material for leek cultivation obtained in each Example and each comparative example was evaluated as follows.

<Evaluation of light transmittance>
The total light transmittance of the agricultural covering material for leek cultivation obtained in each example and each comparative example was measured using a spectrophotometer (manufactured by JASCO Corporation: trade name “V-570”). Among the obtained results, the average transmittance of light in the visible light region having a wavelength of 400 nm to less than 700 nm, the average transmittance of light in the near infrared light region having a wavelength of 700 nm to less than 2000 nm, and the wavelength of 700 nm to less than 2000 nm Table 1 shows the average transmittances of direct light beams in the near-infrared light region.

[Examples 1-6 and Comparative Examples 1-5]
In Examples 1 to 6 and Comparative Examples 1 to 5, each compound was charged into a Henschel mixer according to the compounding amount shown in Table 1, stirred and mixed, then roll kneaded, and then dispensed to a thickness of 0.1 mm with a calendar. Thus, the agricultural covering material for leek cultivation of the present invention was prepared.

  <Test method> On a farmland in Tochigi City, Tochigi Prefecture, a Wonder Greenbelt leek seedling was planted on the main field at a stock interval of 20 cm on November 15, 2005, and a width of 5 m and a length of 10 m on December 25, 2005. Agricultural covering material was spread on an agricultural single building with a center height of 4m (east-west direction). The leaf color, leaf burn, leaf length, leaf width, and yield of the leek harvested on February 1, 2006 were measured.

  The temperature and ground temperature inside the house were measured on January 12, 2006 (weather: fine 13:00, outside temperature 8 ° C, ground temperature 0.7 ° C) at a point 3 meters (2 places in total) from both entrances of the house. It was.

  The evaluation of the leaf color and the leaf burn was performed by visually evaluating the state of the harvested leek according to the following criteria.

Leaf color: (dark) ◎>○>△> × (light)
Burnt leaves: (less) ◎ ＞ ○ ＞ △ ＞ × (more)

  As is clear from the results shown in Table 1, the average transmittance of light in the visible light region of the agricultural coating material for leek cultivation of the present invention is as high as 75% or more, and the light transmittance in the near infrared light region is high. Since the average transmittance is as low as 85% or less, the covering material for leek cultivation of the present invention has a wavelength in the visible light region without excessively transmitting the light having a wavelength in the near infrared light region. It was confirmed that the light beam can be sufficiently transmitted. Moreover, from the value of the average transmittance | permeability of the light ray of such a visible light area | region, it was confirmed that the agricultural covering material for leek cultivation of this invention has high transparency. Therefore, it was confirmed that the agricultural covering material for leek cultivation of the present invention has high transparency and an excellent heat shielding effect. It was also confirmed from each Example and Comparative Example 1 that the effect of absorbing ultraviolet rays was improved by using the titanium oxide and the ultraviolet absorber in the present application together.

  On the other hand, the content of titanium oxide exceeds 0.7 parts by mass relative to 100 parts by mass of the thermoplastic resin. Each of the agricultural coating materials obtained in Comparative Examples 5 and 10 containing 2 μm of titanium oxide for pigments has a low average light transmittance of less than 75% in the visible light region, and has a wavelength of visible light. It was confirmed that the transmission of light in the region was not sufficient. Moreover, the agricultural covering material for leek cultivation obtained in Comparative Examples 1-2 and Comparative Examples 6-7 whose content of titanium oxide is less than 0.2 parts by mass with respect to 100 parts by mass of the thermoplastic resin is close. It has been confirmed that the average transmittance of light rays in the infrared light region exceeds 85%, and light rays having wavelengths in the infrared light region are excessively transmitted. Thus, each agricultural covering material for leek cultivation obtained in Comparative Examples 5 and 10 containing titanium oxide for pigments having a weight average particle diameter of 0.2 μm is the average transmission of light in the near infrared light region. Since the rate exceeded 85%, it was confirmed that the heat shielding effect was also low.

  Furthermore, it was confirmed from the examples and comparative examples that if the direct light transmittance in the near-infrared light region is high, burnt of leek leaves tends to occur, and if it is low, burnt of leek leaves does not occur.

  As described above, according to the present invention, the wavelength is in the near-infrared light region despite being an agricultural covering material for leek cultivation comprising a thermoplastic resin film containing titanium oxide and an ultraviolet absorber. Without excessively transmitting the light beam, the light beam having a wavelength in the visible light region can be sufficiently transmitted, and the direct light of the transmitted light in the near-infrared light region can be reduced to obtain irregularly reflected light. And it becomes possible to provide the agricultural covering material for leek cultivation which makes it possible to have sufficient transparency and the outstanding heat-shielding property.

Therefore, the agricultural covering material for leek cultivation of the present invention, when used in an agricultural house for leek cultivation, reduces the transmission of light in the near-infrared light region and thereby suppresses the temperature rise in the house. The light necessary for the growth of light can be transmitted sufficiently in the visible light range, blocking the ultraviolet rays that cause disease, and the transmitted light in the near infrared light region is also directly irradiated to the leek. As an agricultural covering material used in agricultural facilities such as farmhouses and tunnels for leek cultivation, because it reduces direct light and makes it possible to prevent discoloration and twisting of leek leaves. Useful.

Claims (4)

An agricultural covering material for leek cultivation comprising at least one layer of a thermoplastic resin film, wherein at least one layer of the thermoplastic resin film heats titanium oxide having a weight average particle diameter of 0.6 to 1.5 μm. 0.2 to 0.7 parts by mass with respect to 100 parts by mass of the plastic resin, and 0.1 to 2.0 parts by mass of the ultraviolet absorber with respect to 100 parts by mass of the thermoplastic resin Agricultural covering material for leek cultivation. Light with a wavelength of less than 380 nm in the ultraviolet region is less than 5%, and the average transmittance of light in the ultraviolet region of 380 or more and less than 400 nm is 15% or less, and light in the visible light region of 400 or more and less than 700 nm The average transmittance of light in the near infrared light region having a wavelength of 700 nm or more and less than 2000 nm is 85% or less. Agricultural covering material for cultivation. The agricultural covering material for leek cultivation according to claim 1 or 2, wherein the direct light transmittance of transmitted light having a wavelength of 700 nm or more and less than 2000 nm is 40 to 75%. The leek cultivation method characterized by coat | covering the agricultural covering material for leek cultivation as described in any one of Claims 1 thru | or 3 doubly.