JP4724460B2 - Agricultural film - Google Patents

Description

  The present invention relates to an agricultural film, and more particularly to an agricultural film having a heat shielding performance suitable for an agricultural house or the like.

  Conventionally, agricultural films such as polyolefin resin films and polyvinyl chloride resin films have been used in agricultural facilities such as agricultural houses. However, when such an agricultural film is used for cultivating crops in an agricultural house, there is a problem that the temperature in the house becomes high due to strong sunlight in the summer, which hinders cultivation of the crops. In order to solve such a problem, agricultural films containing titanium oxide to reduce light transmission have been studied and disclosed.

  For example, in Japanese Patent Application Laid-Open No. 61-111350 (Patent Document 1), 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 film is disclosed. In JP 2004-314363 A (Patent Document 2), 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. An agricultural film having a film thickness of 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, a film thickness of 70 to 200 μm, and a light shielding rate of 80% or more is disclosed. Has been. However, in the agricultural film described in Patent Documents 1 and 2, fine particles having a weight average particle diameter of generally about 500 nm or less (preferably 100 nm to 300 nm) in order to efficiently shield sunlight from the titanium oxide to be contained. Diameter titanium oxide was used. Therefore, even if a small amount of titanium oxide pigment is contained, the agricultural film itself becomes white and the appearance and transparency are impaired, and the average transmittance of light rays in the visible light region necessary for photosynthesis is reduced. There was a problem that affected the development.

In Japanese Patent Application Laid-Open No. 11-292996 (Patent Document 3), 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.
Japanese Patent Laid-Open No. 61-111350 JP 2004-314363 A Japanese Patent Laid-Open No. 11-292996

  The present invention has been made in view of the above-mentioned problems of the prior art, and it is an agricultural film provided with a thermoplastic resin film containing titanium oxide. An object of the present invention is to provide an agricultural film that can sufficiently transmit light having a wavelength in the visible light region without excessively transmitting, and that has sufficient transparency and excellent heat shielding properties. And

  As a result of intensive studies to achieve the above object, the present inventors have determined that titanium oxide having a weight average particle diameter of 0.6 to 1.5 μm is 100 mass parts of thermoplastic resin in an agricultural film. By providing at least one layer of a thermoplastic resin film containing 0.2 to 0.7 parts by mass, surprisingly, the wavelength is in the visible light region without excessively transmitting the light beam in the infrared light region. It has been found that it is possible to sufficiently transmit a certain light beam and that it has sufficient transparency and excellent heat shielding properties, and the present invention has been completed.

  That is, the agricultural film of the present invention is an agricultural film including at least one thermoplastic resin film, and at least one layer of the thermoplastic resin film has a weight average particle diameter of 0.6 to 1.5 μm. The titanium oxide is 0.2 to 0.7 parts by mass with respect to 100 parts by mass of the thermoplastic resin.

  Moreover, as the agricultural film of the present invention, the average transmittance of light in the visible light region having a wavelength of 400 nm or more and less than 700 nm is 75% or more, and in the near infrared light region having a wavelength of 700 nm or more and less than 2000 nm. It is preferable that the average transmittance of a certain light beam is 85% or less.

  Furthermore, as the agricultural film of the present invention, it is preferable that the agricultural film includes at least two thermoplastic resin films, and at least one of the thermoplastic resin films is a polyolefin resin film.

  According to the present invention, the wavelength is in the visible light region without excessively transmitting the light having the wavelength in the infrared light region, despite being an agricultural film including a thermoplastic resin film containing titanium oxide. It is possible to provide an agricultural film that can sufficiently transmit light and that has sufficient transparency and excellent heat shielding properties.

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

  The agricultural film of the present invention is an agricultural film comprising at least one thermoplastic resin film, and at least one layer of the thermoplastic resin film has a weight average particle diameter of 0.6 to 1.5 μm. It is characterized by containing 0.2 to 0.7 parts by mass of titanium oxide with respect to 100 parts by mass of the thermoplastic resin.

  The titanium oxide according to the present invention has a weight average particle diameter of 0.6 to 1.5 μm. When such a weight average particle diameter is less than 0.6, when a small amount is contained, the average transmittance of light in the visible light region having a wavelength of 400 nm or more and less than 700 nm decreases and the wavelength is in the vicinity of 700 nm or more and less than 2000 nm. The average transmittance of light in the infrared light region is increased, the resulting agricultural film is white and the transparency is reduced, and the photosynthesis efficiency of the crops in the house covered with the agricultural film is reduced, Further, the heat shielding property is also lowered. On the other hand, when the weight average particle diameter exceeds 1.5, the light scattering efficiency in the near infrared region decreases, and as a result, the average light transmittance in the near infrared region increases and the heat shielding property decreases.

  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.

  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 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.

  Moreover, in the thermoplastic film containing titanium oxide 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, an ultraviolet absorber, a lubricant, Various additives such as pigments, fillers, drip-proofing agents and anti-fogging agents can be added.

  Examples of such a plasticizer include di-2-ethylhexyl phthalate (DOP), di-normal octyl phthalate (n-DOP), diisononyl phthalate (DINP), butyl benzyl phthalate (BBP), phthalate General phthalate plasticizers represented by acid diisodecyl ester (DIDP), phthalate diundecyl ester (DUP), adipic acid dioctyl ester (DOA), sebacic acid dioctyl ester (DOS), azelaic acid dioctyl ester ( Polymers such as general fatty acid ester plasticizers typified by DOZ), trimellitic acid ester plasticizers typified by trimellitic acid trioctyl ester (TOTM), polyester plasticizers typified by polypropylene adipate, etc. Plasticizer Sebacic acid plasticizers, general plasticizers such as chlorinated paraffin, tricresyl phosphate (TCP), trixylyl phosphate (TXP), tris (isopropylphenyl) phosphate, tributyl phosphate, triethyl phosphate, triphenyl phosphate , Phosphate ester plasticizers such as triethylphenyl 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. Polybutadiene, epoxy methyl stearate, butyl epoxy stearate, ethyl hexyl epoxy stearate, tris (epoxypropyl) isocyanurate, 3- (2-xenoxy) -1,2-epoxypropane Bisphenol 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 ultraviolet absorber include salicylic acid esters, benzotriazoles, hydroxybenzophenones, acrylonitrile substituted products, and the like. 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.

  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 titanium oxide according to the present invention is not particularly limited, and a known molding method such as a calendering 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 film 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. That is, the agricultural film of the present invention may have a single layer structure of a thermoplastic resin film containing the titanium oxide, or may have a multilayer structure including other layers other than the thermoplastic resin film containing the titanium oxide.

  Moreover, as the agricultural film of the present invention, an agricultural film comprising at least two or more thermoplastic resin films, and at least one of the thermoplastic resin films being a polyolefin resin film is preferable. In particular, 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. In addition, it is as above-mentioned that a polyolefin-type resin film is preferable as the said thermoplastic resin film.

  In the case where the agricultural film 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. Further, when the agricultural film of the present invention has a multilayer structure, it is preferable that adjacent layers are layers having high compatibility or high 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 multilayered agricultural film is not particularly limited, and a known method can be appropriately employed. For example, a multilayered film can be formed at once by a molding method such as a multilayer coextrusion inflation method. The film may be produced, or a film having a multilayer structure may be produced by forming a single layer thermoplastic resin film and then laminating it.

  The agricultural film of the present invention has an average transmittance of light in the visible light region having a wavelength of 400 nm or more and less than 700 nm and 75% or more, and a wavelength in the near infrared light region of 700 nm or more and less than 2000 nm. The average light transmittance is preferably 85% or less. If the average transmittance of light rays in the visible light region is less than 75%, the resulting agricultural film tends to be unable to sufficiently transmit light rays necessary for growing crops, and in the near infrared light region. When the average light transmittance is 85% or more, sufficient heat shielding properties tend not to be obtained in the region covered with the obtained agricultural film.

  Moreover, it does not restrict | limit especially as thickness of the agricultural film of this invention, It is preferable that it is 50-200 micrometers, and it is more preferable that it is 75-150 micrometers. When the thickness of the agricultural film of the present invention is less than the lower limit, physical properties such as tensile strength of the resulting agricultural film are lowered, and the stretching work during use tends to be difficult.On the other hand, when the upper limit is exceeded, Since the obtained agricultural film is heavy, it tends to be difficult to perform the stretching work during use. When the agricultural film of the present invention has a multilayer structure, the thermoplastic resin film containing titanium oxide according to the present invention has a thickness of 50 to 150 μm from the viewpoint of reliably exhibiting the effects of the present invention. It is preferable to have.

  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 film obtained by each Example and each comparative example was evaluated as follows.

<Evaluation of light transmittance>
The total light transmittance of the agricultural film obtained in each Example and each Comparative Example was measured using a spectrophotometer (manufactured by JASCO Corporation: trade name “V-570”). Table 1 and Table 2 show the average transmittance of light in the visible light region having a wavelength of 400 nm to less than 700 nm and the average transmittance of light in the near infrared light region having a wavelength of 700 nm to less than 2000 nm, respectively. Shown in Moreover, the total light transmittance curve obtained by measuring the agricultural film obtained in Examples 1-6 and Comparative Examples 1-5 is shown in FIG.

[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, an agricultural film of the present invention was prepared.

[Examples 7 to 12 and Comparative Examples 6 to 10]
In Examples 7 to 12 and Comparative Examples 6 to 10, a thermoplastic resin film (outer layer) / ethylene-vinyl acetate copolymer resin film 1 (intermediate layer) / ethylene-vinyl acetate by an inflation method according to the blending amounts shown in Table 2. An agricultural film having a thickness of 0.1 mm (outer layer: intermediate layer: inner layer = 1: 3: 1) having a three-layer structure in which the copolymer resin film 2 (inner layer) was laminated in this order was prepared.

  As is clear from the results shown in Table 1 and Table 2, the average transmittance of light in the visible light region of the agricultural film of the present invention is as high as 75% or more, and the average transmittance of light in the infrared light region. Since both rates are as low as 85% or less, the agricultural film of the present invention sufficiently transmits light having a wavelength in the visible light region without excessively transmitting light having a wavelength in the infrared light region. It was confirmed that Moreover, it was confirmed from the value of the average transmittance | permeability of the light ray of such a visible region that the agricultural film of this invention has high transparency. Therefore, it was confirmed that the agricultural film of the present invention has high transparency and an excellent heat shielding effect.

  On the other hand, each agricultural film obtained in Comparative Examples 3-4 and Comparative Examples 8-9, in which the content of titanium oxide exceeded 0.7 parts by mass with respect to 100 parts by mass of the thermoplastic resin, and the weight average particles In each of the agricultural films obtained in Comparative Examples 5 and 10 containing a titanium oxide for pigment having a diameter of 0.2 μm, the average transmittance of light in the visible light region is as low as less than 75%, and the wavelength is low. It was confirmed that the transmission of light in the visible light region was not sufficient. Moreover, the agricultural films obtained in Comparative Examples 1-2 and Comparative Examples 6-7, in which the content of titanium oxide is less than 0.2 parts by mass with respect to 100 parts by mass of the thermoplastic resin, are all in the near infrared region. The average transmittance of the light beam exceeds 85%, and it was confirmed that the light beam having the wavelength in the infrared region is excessively transmitted. Thus, each agricultural film obtained in Comparative Examples 5 and 10 containing titanium oxide for pigments having a weight average particle diameter of 0.2 μm has an average light transmittance of 85% in the near infrared region. Therefore, it was confirmed that the heat shielding effect was low.

  As described above, according to the present invention, although the film is an agricultural film including a thermoplastic resin film containing titanium oxide, the wavelength does not excessively transmit light rays in the infrared region. It is possible to provide an agricultural film that can sufficiently transmit light in the visible light region and that has sufficient transparency and excellent heat shielding properties.

  Therefore, when the agricultural film of the present invention is used for, for example, an agricultural house, it is possible to sufficiently transmit light having a wavelength necessary for growing crops in the visible light region while suppressing temperature rise in the house. Since it has excellent heat shielding properties, it is useful as a film for use in agricultural facilities such as agricultural houses and tunnels.

It is a graph which shows the total light transmittance curve of the film for agriculture obtained in Examples 1-6 and Comparative Examples 1-5.

Claims (3)

  An agricultural film provided with at least one thermoplastic resin film, wherein at least one layer of the thermoplastic resin film is made of titanium oxide having a weight average particle diameter of 0.6 to 1.5 μm. An agricultural film comprising 0.2 to 0.7 parts by mass with respect to parts.   The average transmittance of light in the visible light region having a wavelength of 400 nm or more and less than 700 nm is 75% or more, 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 is 85% or less. The agricultural film according to claim 1, wherein the film is an agricultural film.   The agricultural film according to claim 1 or 2, wherein the agricultural film comprises at least two thermoplastic resin films, and at least one of the thermoplastic resin films is a polyolefin resin film. the film.

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