JP2005118032A - Agricultural film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an agricultural film excellent in mechanical strength, weather resistance, heat resistance, chemical resistance, workability in spreading, etc., and capable of being suitably used even in a severe working condition represented by fruit cultivation on an inclined slope of hilly land, etc. <P>SOLUTION: This agricultural film is formed by laminating both surfaces of a intermediate layer having a thickness of ≥20 μm with surface layers each having a thickness of ≥5 μm, so as to have a thickness of 30-150 μm in total, wherein the intermediate layer is formed out of a low-density polyethylene resin containing at least one or more kinds of hindered amine-based compounds and having a density of 0.90-0.93 g/cm<SP>3</SP>and a mass flow rate (MFR) of 0.5-4.0 g/10 min (190°C), and each of the surface layers is formed out of an ethylene-vinyl acetate copolymer having a vinyl acetate content of 3-7 wt% and a MFR of 0.5-4.0 g/10 min (190°C) or an ethylene-methyl methacrylate copolymer having a methyl methacrylate content of 3-7 wt% and a MFR of 0.5-10.0 g/10 min (190°C). <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to an agricultural film used in a crop cultivation facility. More specifically, the present invention relates to an agricultural film that is coated and spread on the outer surface of a cultivation facility composed of a metal pipe or the like and is used for purposes such as heat insulation, rain protection, and wind protection. More specifically, the present invention relates to an agricultural film that is suitably used for cultivation facilities on hilly slopes represented by fruit tree cultivation. In addition, the present invention relates to an agricultural film that is spread on the inner surface of a cultivation facility (as a lining film) in order to mainly create a sealed space and enhance a heat retaining effect.

  Conventionally, as a plastic film that is coated and spread on a farm growing facility, an agricultural polyvinyl chloride resin film (hereinafter referred to as “agricultural PVC film”) and an agricultural polyolefin resin film (hereinafter referred to as “agriculture”). In general, "PO film for use") is used. These agricultural films are always used outdoors, so ultraviolet rays contained in sunlight, heat received from components of cultivation facilities heated by sunlight, chemicals such as fertilizers and agricultural chemicals used in cultivation facilities, Is exposed to degradation factors due to acid rain and the like. On the other hand, these agricultural films are being developed in the direction of thinning because of the demands for facilitating the covering and spreading work, reducing the amount of waste after use, and reducing the cost of cultivation facilities.

  Agricultural PVC films that have been widely used in the past are excellent in heat retention, weather resistance, transparency, workability, etc., but in recent years there is concern about the generation of toxic gases during incineration disposal after use. Its use is decreasing. On the other hand, recently, the use of agricultural PO film has been rapidly increasing as an agricultural film to replace agricultural PVC film. The agricultural PO film has many advantages over the agricultural PVC film, such as lightness, price, processability, mechanical strength, and ease of disposal.

  However, compared to agricultural PVC film, agricultural PO film has a weaker aspect against the deterioration factors in outdoor use. Various studies have been made to enable outdoor use.

  As a method for improving the resistance of the agricultural PO film to the deterioration factor, for example, a polyolefin containing a hindered amine compound as a stabilizer is disclosed. (Patent Document 1)

JP 59-86645 A

  However, when the polyolefin is formed into a film, for example, there is a problem that the hindered amine compound is likely to disappear in a short period of time under conditions involving moisture, and the efficacy is easily lost in a short period of time.

Moreover, as a film which can maintain the efficacy of a hindered amine compound for a long period of time, for example, 0.1 to 2.0% by weight of a hindered amine compound and an inorganic fine powder having a polarity of a surface area of 10 m ² / g or more 0.5 to A thermoplastic synthetic resin film having an excellent weather resistance and containing 20% by weight is disclosed. (Patent Document 2)
JP-A-56-41254

  However, since the thermoplastic synthetic resin film contains an inorganic fine powder together with a hindered amine compound, the transparency is remarkably lowered, and there is a problem that it becomes unsuitable for use as an agricultural coating film. .

Furthermore, lithium aluminum composite hydroxide is used for 100 parts by weight of a polyolefin resin having a vinyl acetate content of 10 to 20% by weight in a copolymer of vinyl acetate and olefin or a mixture of the copolymer and a polyolefin resin. On one or both sides of a base material layer having a thickness of 30 to 180 μm comprising a resin composition containing 1 to 20 parts by weight of a salt, 0.05 to 3 parts by weight of a hindered amine compound and 1 to 4 parts by weight of an antifogging agent, A coating layer comprising a polyolefin resin or a copolymer of vinyl acetate and olefin, or a mixture of the copolymer and a polyolefin resin, and a polyolefin resin having a vinyl acetate content of 9% by weight or less and having a thickness of 10 to 50 μm Agricultural PO-type film provided with a film is also disclosed. (Patent Document 3)
JP 7-312996 A

  However, conventional agricultural PO films have been mainly used in cultivation facilities generally called houses installed on flat ground, and the crops grown are basically vegetables and flowers. . Therefore, large tension is not continuously applied to agricultural films, and a large amount of chemicals showing acidity or basicity is rarely applied, and the film is partially exposed to a large amount of ultraviolet rays or high temperatures. There are few things.

  On the other hand, fruit tree cultivation, especially grape cultivation, is often carried out in hilly areas, and the tension concentrates on the slopes at high elevations. The south-facing slope has a large amount of ultraviolet light per unit area, and the air under the agricultural film heated by sunlight rises along the slope and the upper part becomes hot. In addition, a strong basic lime-sulfur mixture is constantly sprayed with a large amount of dilution water. Under such severe conditions, conventional agricultural films are insufficient, and there is a demand for agricultural films having higher mechanical strength and better weather resistance. Furthermore, since the agricultural film expansion work on the inclined surface in the hilly area is a very heavy labor and the framework of the cultivation facility is often in a simple form, there is a demand for a thinner agricultural film.

  Moreover, if the said agricultural PO-type film is used in a cultivation facility as a lining film, a film will shrink | contract large with time passage. For this reason, even if the film is expanded to create a sealed space to obtain a heat retaining effect, a gap is formed because the film is contracted, and the desired heat retaining effect cannot be obtained. In addition, if the film is stored in layers when it is not used from early spring to summer, the film may be blocked (fused) when the film is spread from autumn to winter. Furthermore, in the cultivation of strawberries, chrysanthemum, roses, etc., the insect pests are often exterminated by sulfur fumigation. When the above-mentioned agricultural PO film is used in such an environment, the film deterioration rapidly proceeds and the agricultural chemical resistance is increased. Was insufficient.

  In view of the above problems and demands, the object of the present invention is excellent in mechanical strength, weather resistance, heat resistance, chemical resistance, stretch workability, etc., and is harsh as represented by fruit tree cultivation on inclined surfaces such as hills. Another object of the present invention is to provide an agricultural film that can be suitably used even under various usage environments. In addition, even when used as a lining film, there is little shrinkage after the passage of time, it is difficult for fusion at high temperatures to occur, and even when agricultural chemicals such as sulfur fumigation are used, film deterioration is unlikely to proceed. To provide films with excellent pesticide resistance

The agricultural film according to the invention of the present invention (the present invention) contains at least one or more hindered amine compounds, has a density of 0.90 to 0.93 g / cm ³ , and has a melt mass flow rate (MFR). The vinyl acetate content is 3 to 7% by weight and the MFR is 0 on both surfaces of an intermediate layer having a thickness of 20 μm or more, which is made of a low density polyethylene resin having a thickness of 0.5 to 4.0 g / 10 min (190 ° C.) A surface layer of 5 to 4.0 g / 10 min (190 ° C.) of an ethylene-vinyl acetate copolymer having a thickness of 5 μm or more is laminated, and the total thickness is 30 to 150 μm. Features.

  The intermediate layer (inner layer) constituting the agricultural film of the present invention has a mechanical strength that can withstand the tension applied by being spread on an inclined surface such as a hilly area, and the agricultural film due to a partially raised temperature state. Has a role of preventing softening.

  The intermediate layer needs to be formed of a low density polyethylene resin (hereinafter referred to as “LDPE”). Among LDPE, an ethylene-α-olefin copolymer, that is, a linear low density polyethylene resin is used. (Hereinafter referred to as “LLDPE”).

The LDPE is necessary that the density is 0.90~0.93g / cm ^3, preferably 0.91~0.92g / cm ^3. In addition, the density said by this invention means the density measured based on JISK7112 "The measurement method of the density of non-foamed plastics and specific gravity".

When the density of the LDPE is less than 0.90 g / cm ³ , the mechanical strength of the resulting agricultural film becomes insufficient, making it unsuitable for stretching work and lowering the flexural modulus. Blocking (fusion) phenomenon occurs when folded and stored. On the other hand, when the density of the LDPE exceeds 0.93 g / cm ³ , the transparency of the obtained agricultural film is lowered, resulting in inconvenience for use as an agricultural film.

  The LDPE needs to have a melt mass flow rate (MFR) of 0.5 to 4.0 g / 10 min (190 ° C.). The MFR referred to in the present invention refers to JIS K 7210 “Testing methods for melt mass flow rate (MFR) and melt volume flow rate (MVR) of plastic-thermoplastic plastic” at a temperature of 190 ° C. and a load of 21.degree. It means MFR measured under the condition of 18N.

  When the MFR of the LDPE is less than 0.5 g / 10 min (190 ° C.), the film forming property (productivity) of the agricultural film is inhibited. On the other hand, when the MFR of LDPE exceeds 4.0 g / 10 min (190 ° C.), the mechanical strength of the resulting agricultural film becomes insufficient. In addition, when using a coextrusion method as a manufacturing method (film forming method) of the agricultural film of this invention, MFR and the intermediate | middle layer of the ethylene-vinyl acetate copolymer used in order to form both the surface layers mentioned later are used. It is preferable to keep the MFR of the LDPE used for forming as close as possible.

  The LDPE needs to contain at least one or more hindered amine compounds. By including at least one or more hindered amine compounds in LDPE, the weather resistance of the resulting agricultural film is significantly improved.

The hindered amine compound is not particularly limited, and any conventionally known hindered amine compound is used. For example, dimethyl succinate-1- (2-hydroxyethyl) -4-hydroxy-2,2,6,6-tetramethylpiperidine polycondensate, tetrakis (2,2,6,6-tetramethyl-4-piperidyl ) -1,2, ^3, 4-butane tetra-carboxylate, poly {[6 - [(1,1,3,3-tetramethylbutyl) amino] -1,3,5-triazine-2,4-diyl ] [(2,2,6,6-tetramethyl-4-piperidyl) imino] hexamethylene [(2,2,6,6-tetramethyl-4-piperidyl) imino]} and the like. These hindered amine compounds may be used alone or in combination of two or more.

  The LDPE may contain, for example, a heat stabilizer, an antioxidant (anti-aging agent), an ultraviolet absorber, etc., as necessary, as long as the achievement of the object of the present invention is not hindered.

  The heat stabilizer is not particularly limited, and any conventionally known heat stabilizer may be used. For example, chelators such as metal salts of carboxylic acids, phenolic antioxidants, organic phosphites, etc. Etc. These heat stabilizers may be used alone or in combination of two or more.

  As the antioxidant, any conventionally known antioxidant may be used, but usually there are many which have an effect as the heat stabilizer, and it is not particularly limited. For example, a metal of carboxylic acid Examples thereof include chelators such as salts, phenolic antioxidants, and organic phosphites. These antioxidants may be used alone or in combination of two or more.

  The ultraviolet absorber may be any conventionally known ultraviolet absorber, and is not particularly limited. For example, 2,4-dihydroxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 2-hydroxy- Benzophenone ultraviolet rays such as 4-dodecyloxybenzophenone, 2,2′-dihydroxy-4-methoxybenzophenone, 2,2′-hydroxy-4,4′-dimethoxybenzophenone, 2-hydroxy-4-methoxy-5-sulfobenzophenone Absorbent, 2- (2′-hydroxy-5′-tert-butylphenyl) benzotriazole, 2- (2′-hydroxy-5′-methylphenyl) benzotriazole, 2- (2′-hydroxy-3′- tert-butyl-5-methylphenyl) -5-chlorobenzotria 2- (2′-hydroxy-3 ′, 5′-di-tert-butylphenyl) -5-chlorobenzotriazole, 2- (2′-hydroxy-3 ′, 5′-di-tert-amyl) Examples thereof include benzotriazole ultraviolet absorbers such as phenyl) -5-chlorobenzotriazole, salicylic acid ester ultraviolet absorbers, and cyanoacrylate ultraviolet absorbers. These ultraviolet absorbers may be used alone or in combination of two or more.

The LDPE preferably contains no antifogging agent. Since the antifogging agent has the property of migrating to the surface of the intermediate layer and thus to the surface of the agricultural film, when the antifogging agent is contained, the hindered amine compound and the UV absorber are added to the surface of the intermediate layer together with the antifogging agent. It will move to the surface of an agricultural film, and the weather resistance of an agricultural film, especially the durability of the weather resistance over a long period of time will decrease. Therefore, when it is unavoidable to contain an antifogging agent, the content of the antifogging agent in the intermediate layer is preferably less than 20000 ppm.

  The LDPE preferably contains no inorganic fine particles such as a humectant. Inorganic fine particles such as humectants have an action of capturing acidic substances and basic substances contained in chemicals such as fertilizers and agricultural chemicals, and consequently promote deterioration of agricultural films. Therefore, when it is unavoidable to contain inorganic fine particles such as a humectant, the content of inorganic fine particles such as a humectant in the intermediate layer is preferably less than 7% by weight.

  The intermediate layer constituting the agricultural film of the present invention needs to have a thickness of 20 μm or more. When the thickness of the intermediate layer is less than 20 μm, the mechanical strength and heat resistance of the obtained agricultural film are insufficient. The upper limit of the thickness of the intermediate layer is not particularly limited, and may be set as appropriate without departing from the overall thickness of the agricultural film of the present invention.

  The surface layer (outer layer) constituting the agricultural film of the present invention has a function of preventing the occurrence of fine cracks (cracks) generated on the surface of the agricultural film due to ultraviolet rays or moisture. Acidic substances and basic substances such as lime-sulfur mixtures that are sprayed as agricultural chemicals penetrate into the cracks on the surface of agricultural films together with moisture, thereby significantly accelerating the deterioration of the physical properties of agricultural films.

  The surface layer needs to be formed of an ethylene-vinyl acetate copolymer (hereinafter referred to as “EVA”).

  The EVA needs to have a vinyl acetate content of 3 to 7% by weight. When the vinyl acetate content of EVA is less than 3% by weight, the surface layer becomes insufficiently flexible and cannot sufficiently perform the function of preventing the occurrence of fine cracks generated on the surface of the resulting agricultural film. . On the other hand, when the vinyl acetate content of EVA exceeds 7% by weight, a blocking phenomenon tends to occur during storage of the resulting agricultural film.

  The EVA needs to have an MFR of 0.5 to 4.0 g / 10 minutes (190 ° C.) measured under the conditions of a temperature of 190 ° C. and a load of 21.18 N in accordance with JIS K 7210. And preferably 0.8 to 2.0 g / 10 min (190 ° C.).

  When the EVA MFR is less than 0.5 g / 10 min (190 ° C.), the film-forming property (productivity) of the agricultural film is inhibited. On the other hand, when the MFR of the EVA exceeds 4.0 g / 10 min (190 ° C.), the breaking strength of the surface layer is lowered, and therefore the function of preventing the occurrence of fine cracks generated on the surface of the obtained agricultural film. It will not be enough.

  The EVA may contain an antifogging agent as necessary within a range that does not impede achievement of the object of the present invention so that condensed water droplets can flow quickly. Further, an antifogging film may be formed.

  The antifogging agent may be any conventionally known antifogging agent and is not particularly limited. For example, glycerin stearic acid ester, diglycerin stearic acid ester, polyglycerin stearic acid ester, sorbitol stearic acid ester And polyhydric alcohol fatty acid esters such as polyhydric alcohol unsaturated fatty acid esters such as glycerin oleate and diglycerin oleate. These antifogging agents may be used alone or in combination of two or more.

  Further, the antifogging film is not particularly limited, but for example, a coating film of an inorganic oxide sol represented by colloidal silica or colloidal alumina, the inorganic oxide sol and, for example, a surfactant or a resin. Coating films composed of organic compounds such as, coating films of liquids mainly composed of surfactants, such as films composed mainly of hydrophilic resins such as polyvinyl alcohol, polyethylene oxide, polysaccharides and polyacrylic acid It is done. These anti-fogging films may be used alone or in combination of two or more. Moreover, these anti-fogging films may be a single layer or a multilayer of two or more layers.

  In the above EVA, if necessary within the range that does not hinder the achievement of the subject of the present invention, for example, the same heat stabilizer, antioxidant, ultraviolet absorber, etc. that may be contained in the intermediate layer, Any conventionally known additive may be contained.

  However, it is preferable that the EVA does not contain inorganic fine particles such as a heat retaining agent or an anti-blocking agent. As described above, inorganic fine particles such as a heat retaining agent and an anti-blocking agent have an action of capturing acidic substances and basic substances contained in chemicals such as fertilizers and agricultural chemicals. Deterioration is accelerated, and transparency of the surface layer and thus the agricultural film is hindered. Therefore, when it is unavoidable to contain inorganic fine particles such as a heat retaining agent or an anti-blocking agent, the content of the inorganic fine particles such as a heat retaining agent or an anti-blocking agent in the surface layer should be as small as possible. It is preferable.

  The surface layer constituting the agricultural film of the present invention needs to have a thickness of 5 μm or more. When the thickness of the surface layer is less than 5 μm, the function of preventing generation of fine cracks generated on the surface of the agricultural film due to ultraviolet rays, moisture, or the like cannot be sufficiently achieved. In addition, the upper limit of the thickness of the surface layer is not particularly limited, and may be set as appropriate without departing from the overall thickness of the agricultural film of the present invention.

  The agricultural film of the present invention is formed by laminating the surface layer (outer layer) made of the EVA on both surfaces of the intermediate layer (inner layer) made of the LDPE, preferably LLDPE.

  The agricultural film of the present invention needs to have a total thickness of 30 to 150 μm, and preferably 50 to 100 μm.

  If the total thickness of the agricultural film is less than 30 μm, the absolute mechanical strength of the agricultural film becomes insufficient, and it can be easily broken by mechanical forces such as strong winds. The mechanical weather resistance becomes insufficient, and the mechanical strength is significantly lowered due to the progress of deterioration. On the other hand, if the total thickness of the agricultural film exceeds 150 μm, the weight per unit area of the agricultural film becomes excessive, and it becomes difficult to perform the expansion work on an inclined surface such as a hilly area. Cost per unit area increases, which is economically disadvantageous.

  The agricultural film production method (film production method) of the present invention may be any conventionally known film production method, and is not particularly limited. For example, a multilayer inflation method, a multilayer T-die extrusion method, a multilayer Examples thereof include an extrusion laminating method and a multilayer calendering method.

  The use of the agricultural film of the present invention is not particularly limited. For example, it can be suitably used for fruit tree cultivation on an inclined surface such as the hilly land, and it is necessary to have light weight and high mechanical strength. It can also be suitably used in fields where it is inevitable that chemicals such as fertilizers and agricultural chemicals adhere to agricultural films. For example, curtains used in agricultural houses and rain protection of composting plants correspond to the above-mentioned fields.

The agricultural film according to the invention of the second aspect (the present invention) contains at least one or more hindered amine compounds, has a density of 0.90 to 0.93 g / cm ³ , and has a melt mass flow rate (MFR). The methyl methacrylate content is 3 to 7% by weight on both sides of the intermediate layer having a thickness of 20 μm or more and made of a low density polyethylene resin having a thickness of 0.5 to 4.0 g / 10 min (190 ° C.), and the MFR is 0. A surface layer made of an ethylene-methyl methacrylate copolymer having a thickness of 5 to 10.0 g / 10 minutes (190 ° C.) having a thickness of 5 μm or more is laminated, and the total thickness is 30 to 150 μm. Features.

  The intermediate layer (inner layer) constituting the agricultural film of the present invention has a mechanical strength that can withstand the tension applied by being spread on an inclined surface such as a hilly area, and the agricultural film due to a partially raised temperature state. Has a role of preventing softening.

  The intermediate layer needs to be formed of a low density polyethylene resin (hereinafter referred to as “LDPE”). Among LDPE, an ethylene-α-olefin copolymer, that is, a linear low density polyethylene resin is used. (Hereinafter referred to as “LLDPE”).

The LDPE is necessary that the density is 0.90~0.93g / cm ^3, preferably 0.91~0.92g / cm ^3. In addition, the density said by this invention means the density measured based on JISK7112 "The measurement method of the density of non-foamed plastics and specific gravity".

When the density of LDPE is less than 0.90 g / cm ³ , the mechanical strength of the resulting agricultural film becomes insufficient, making it unsuitable for stretching work and lowering the flexural modulus. Blocking (fusion) phenomenon occurs when folded and stored. On the other hand, when the density of the LDPE exceeds 0.93 g / cm ³ , the transparency of the obtained agricultural film is lowered, resulting in inconvenience for use as an agricultural film.

  The LDPE needs to have a melt mass flow rate (MFR) of 0.5 to 4.0 g / 10 min (190 ° C.). The MFR referred to in the present invention refers to JIS K 7210 “Testing methods for melt mass flow rate (MFR) and melt volume flow rate (MVR) of plastic-thermoplastic plastic” at a temperature of 190 ° C. and a load of 21.degree. It means MFR measured under the condition of 18N.

  When the MFR of the LDPE is less than 0.5 g / 10 min (190 ° C.), the film forming property (productivity) of the agricultural film is inhibited. On the other hand, when the MFR of the LDPE exceeds 4.0 g / 10 minutes (190 ° C.), the mechanical strength of the obtained agricultural film becomes insufficient. In addition, when using a coextrusion method as a manufacturing method (film forming method) of the agricultural film of this invention, MFR and intermediate layer of the ethylene-methylmethacrylate copolymer used in order to form the surface layer mentioned later are formed. It is preferable that the MFR of the LDPE used for the purpose is as close as possible.

  The LDPE needs to contain at least one or more hindered amine compounds. By including at least one or more hindered amine compounds in LDPE, the weather resistance of the resulting agricultural film is significantly improved.

  The hindered amine compound may be any conventionally known hindered amine compound and is not particularly limited. For example, dimethyl-1- (2-hydroxyethyl) -4-hydroxy-2,2, succinate 6,6-tetramethylpiperidine polycondensate, tetrakis (2,2,6,6-tetramethyl-4-piperidyl) -1,2,3,4-butanetetracarboxylate, poly {[6-[(1 , 1,3,3-tetramethylbutyl) amino] -1,3,5-triazine-2,4-diyl] [(2,2,6,6-tetramethyl-4-piperidyl) imino] hexamethylene [ (2,2,6,6-tetramethyl-4-piperidyl) imino]} and the like. These hindered amine compounds may be used alone or in combination of two or more.

  The LDPE may contain, for example, a heat stabilizer, an antioxidant (anti-aging agent), an ultraviolet absorber, etc., as necessary, as long as the achievement of the object of the present invention is not hindered.

  The heat stabilizer may be any conventionally known heat stabilizer, and is not particularly limited. Examples thereof include carboxylic acid metal salts, phenolic antioxidants, chelators such as organic phosphites, and the like. Can be mentioned. These heat stabilizers may be used alone or in combination of two or more.

As the antioxidant, any conventionally known antioxidant may be used, but usually there are many which have an effect as the heat stabilizer, and it is not particularly limited. For example, a metal of carboxylic acid Examples thereof include chelators such as salts, phenolic antioxidants, and organic phosphites. These antioxidants may be used alone or in combination of two or more.

  The ultraviolet absorber may be any conventionally known ultraviolet absorber, and is not particularly limited. For example, 2,4-dihydroxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 2-hydroxy- Benzophenone ultraviolet rays such as 4-dodecyloxybenzophenone, 2,2′-dihydroxy-4-methoxybenzophenone, 2,2′-hydroxy-4,4′-dimethoxybenzophenone, 2-hydroxy-4-methoxy-5-sulfobenzophenone Absorbent, 2- (2′-hydroxy-5′-tert-butylphenyl) benzotriazole, 2- (2′-hydroxy-5′-methylphenyl) benzotriazole, 2- (2′-hydroxy-3′- tert-butyl-5-methylphenyl) -5-chlorobenzotria 2- (2′-hydroxy-3 ′, 5′-di-tert-butylphenyl) -5-chlorobenzotriazole, 2- (2′-hydroxy-3 ′, 5′-di-tert-amyl) Examples thereof include benzotriazole ultraviolet absorbers such as phenyl) -5-chlorobenzotriazole, salicylic acid ester ultraviolet absorbers, and cyanoacrylate ultraviolet absorbers. These ultraviolet absorbers may be used alone or in combination of two or more.

The LDPE preferably contains no antifogging agent. Since the antifogging agent has the property of migrating to the surface of the intermediate layer and thus to the surface of the agricultural film, if it contains an antifogging agent, the hindered amine compound and the UV absorber together with the antifogging agent It will move to the surface of an agricultural film, and the weather resistance of an agricultural film, especially the durability of the weather resistance over a long period of time will decrease. Therefore, when it is unavoidable to contain an antifogging agent, the content of the antifogging agent in the intermediate layer is preferably less than 20000 ppm.

  The LDPE preferably contains no inorganic fine particles such as a humectant. Inorganic fine particles such as humectants have an action of capturing acidic substances and basic substances contained in chemicals such as fertilizers and agricultural chemicals, and consequently promote deterioration of agricultural films. Therefore, when it is unavoidable to contain inorganic fine particles such as a humectant, the content of inorganic fine particles such as a humectant in the intermediate layer is preferably less than 7% by weight.

  The intermediate layer constituting the agricultural film of the present invention needs to have a thickness of 20 μm or more. When the thickness of the intermediate layer is less than 20 μm, the mechanical strength and heat resistance of the obtained agricultural film are insufficient. In addition, the upper limit of the thickness of the said intermediate | middle layer is not specifically limited, What is necessary is just to set suitably in the range which does not deviate from the whole thickness (30-150 micrometers) of the agricultural film of this invention.

  The surface layer (outer layer) constituting the agricultural film of the present invention has a function of preventing the occurrence of fine cracks (cracks) generated on the surface of the agricultural film due to ultraviolet rays or moisture. Acidic substances and basic substances such as lime-sulfur mixtures that are sprayed as agricultural chemicals penetrate into the cracks on the surface of agricultural films together with moisture, thereby significantly accelerating the deterioration of the physical properties of agricultural films.

  The surface layer needs to be formed from an ethylene-methyl methacrylate copolymer (hereinafter referred to as “EMMA”).

  The EMMA needs to have a methyl methacrylate content of 3 to 7% by weight. When the methyl methacrylate content of EMMA is less than 3% by weight, the flexibility of the surface layer becomes insufficient, and the function of preventing the occurrence of fine cracks generated on the surface of the resulting agricultural film cannot be sufficiently achieved. . On the other hand, when the methyl methacrylate content of EMMA exceeds 7% by weight, a blocking phenomenon tends to occur during storage of the resulting agricultural film.

  The EMMA should have an MFR of 0.5 to 10.0 g / 10 min (190 ° C.) measured under the conditions of a temperature of 190 ° C. and a load of 21.18 N in accordance with JIS K 7210. And preferably 0.8 to 5.0 g / 10 min (190 ° C.).

  When the MFR of the EMMA is less than 0.5 g / 10 min (190 ° C.), the film forming property (productivity) of the agricultural film is inhibited. On the other hand, when the MFR of the EMMA exceeds 10.0 g / 10 min (190 ° C.), the breaking strength of the surface layer is lowered, and thus the function of preventing the occurrence of fine cracks generated on the surface of the obtained agricultural film. It will not be enough.

  The above EMMA may contain an antifogging agent as necessary within a range that does not impede achievement of the object of the present invention so that condensed water droplets flow quickly. Further, an antifogging film may be formed.

  The antifogging agent may be any conventionally known antifogging agent and is not particularly limited. For example, glycerin stearic acid ester, diglycerin stearic acid ester, polyglycerin stearic acid ester, sorbitol stearic acid ester And polyhydric alcohol fatty acid esters such as polyhydric alcohol unsaturated fatty acid esters such as glycerin oleate and diglycerin oleate. These antifogging agents may be used alone or in combination of two or more.

  Further, the antifogging film is not particularly limited, but for example, a coating film of an inorganic oxide sol represented by colloidal silica or colloidal alumina, the inorganic oxide sol and, for example, a surfactant or a resin. Coating films composed of organic compounds such as, coating films of liquids mainly composed of surfactants, such as films composed mainly of hydrophilic resins such as polyvinyl alcohol, polyethylene oxide, polysaccharides and polyacrylic acid It is done. These anti-fogging films may be used alone or in combination of two or more. Moreover, these anti-fogging films may be a single layer or a multilayer of two or more layers.

  In the above EMMA, if necessary within the range not inhibiting the achievement of the subject of the present invention, for example, the same heat stabilizer, antioxidant, ultraviolet absorber, etc. that may be contained in the intermediate layer, Any conventionally known additive (compounding agent) may be contained.

  However, it is preferable that the EMMA does not contain inorganic fine particles such as a heat retaining agent or an anti-blocking agent. As described above, inorganic fine particles such as a heat retaining agent and an anti-blocking agent have an action of capturing acidic substances and basic substances contained in chemicals such as fertilizers and agricultural chemicals. Deterioration is accelerated, and transparency of the surface layer and thus the agricultural film is hindered. Therefore, when it is unavoidable to contain inorganic fine particles such as a heat retaining agent or an anti-blocking agent, the content of the inorganic fine particles such as a heat retaining agent or an anti-blocking agent in the surface layer should be as small as possible. It is preferable.

  The surface layer constituting the agricultural film of the present invention needs to have a thickness of 5 μm or more. When the thickness of the surface layer is less than 5 μm, the function of preventing generation of fine cracks generated on the surface of the agricultural film due to ultraviolet rays, moisture, or the like cannot be sufficiently achieved. In addition, the upper limit of the thickness of the said surface layer is not specifically limited, What is necessary is just to set suitably in the range which does not deviate from the whole thickness (30-150 micrometers) of the agricultural film of this invention.

  The agricultural film of the present invention is formed by laminating a surface layer (outer layer) made of EMMA on both sides of an intermediate layer (inner layer) made of LDPE, preferably LLDPE.

  The agricultural film of the present invention needs to have a total thickness of 30 to 150 μm, and preferably 50 to 100 μm.

  If the total thickness of the agricultural film is less than 30 μm, the absolute mechanical strength of the agricultural film becomes insufficient, and it can be easily broken by mechanical forces such as strong winds. The mechanical weather resistance becomes insufficient, and the mechanical strength is significantly lowered due to the progress of deterioration. On the other hand, if the total thickness of the agricultural film exceeds 150 μm, the weight per unit area of the agricultural film becomes excessive, and it becomes difficult to perform the expansion work on an inclined surface such as a hilly area. Cost per unit area increases, which is economically disadvantageous.

  The agricultural film production method (film production method) of the present invention may be any conventionally known film production method, and is not particularly limited. For example, a multilayer inflation method, a multilayer T-die extrusion method, a multilayer Examples thereof include an extrusion laminating method and a multilayer calendering method.

  The use of the agricultural film of the present invention is not particularly limited. For example, it can be suitably used for fruit tree cultivation on an inclined surface such as the hilly land, and it is necessary to have light weight and high mechanical strength. It can also be suitably used in fields where it is inevitable that chemicals such as fertilizers and agricultural chemicals adhere to agricultural films. For example, curtains used in agricultural houses and rain protection of composting plants correspond to the above-mentioned fields.

The inventions of claims 3 and 4 contain at least one or more hindered amine compounds, have a density of 0.90 to 0.93 g / cm ³ and a melt mass flow rate (MFR) of 0.5 to 4. Ethylene-vinyl acetate containing at least one kind of hindered amine compound on at least one side of an intermediate layer having a thickness of 20 μm or more comprising a linear low density polyethylene resin of 0.0 g / 10 min (190 ° C.) A surface layer made of a copolymer or an ethylene-methyl methacrylate copolymer and having a thickness of 5 μm or more is laminated, and the total thickness is set to 30 to 150 μm.

  The intermediate layer (or the surface facing the outside of the house) constituting the agricultural film of the present invention has a mechanical strength that can withstand the tension applied by being spread on an inclined surface such as a hilly area, and a partially generated rise. It has a role of preventing the agricultural film from being softened by the temperature state. Further, when used as a lining film, it also has a role of reducing shrinkage after a lapse of time.

  The intermediate layer needs to be formed of a linear low density polyethylene resin (hereinafter referred to as “LLDPE”).

The LLDPE is required to be a density of 0.90~0.93g / cm ^3, preferably 0.91~0.92g / cm ^3. In addition, the density said by this invention means the density measured based on JISK7112 "Plastic-the measuring method of the density and specific gravity of non-foamed plastic". If the density of LLDPE is less than 0.90 g / cm ³ , the resulting agricultural film has insufficient mechanical strength, making it unsuitable for stretching work and lowering the flexural modulus. Blocking (fusion) phenomenon occurs during storage. On the other hand, when the density of the LLDPE exceeds 0.93 g / cm ³ , the transparency of the obtained agricultural film is lowered, resulting in inconvenience for use as an agricultural film.

  The LLDPE needs to have a melt mass flow rate (MFR) of 0.5 to 4.0 g / 10 min (190 ° C.). The MFR referred to in the present invention is a temperature of 190 ° C. and a load of 21.18 N in accordance with JIS K7210 “Testing method for melt mass flow rate (MFR) and melt volume flow rate (MVR) of plastic-thermoplastic plastic”. MFR measured under the following conditions.

  When the MFR of the LLDPE is less than 0.5 g / 10 minutes (190 ° C.), the film formability (productivity) of the agricultural film is hindered. On the other hand, if the MFR of the LLDPE exceeds 4.0 g / 10 min (190 ° C.), the mechanical strength of the resulting agricultural film becomes insufficient. In addition, when using a coextrusion method as a manufacturing method (film-forming method) of the agricultural film of this invention, the ethylene-vinyl acetate copolymer or ethylene-methylmethacrylate copolymer used for forming the surface layer mentioned later It is preferable that the MFR of the combined LFR and the MFR of the LLDPE used for forming the intermediate layer are kept as close as possible.

Furthermore, it is preferable that LLDPE does not contain a low density polyethylene resin (hereinafter referred to as “LDPE”). Addition of LDPE may reduce the mechanical strength of the film. Therefore, when it is necessary to add LDPE for film formation (production), it is preferable that the amount be 30 parts by weight or less with respect to 100 parts by weight of LLDPE.

  The LLDPE needs to contain at least one or more hindered amine compounds. By including at least one kind of hindered amine compound in LLDPE, the weather resistance and agricultural chemical resistance of the resulting agricultural film are significantly improved.

  The hindered amine compound may be any conventionally known hindered amine compound, and is not particularly limited. Specifically, dimethyl succinate-1- (2-hydroxyethyl) -4-hydroxy-2,2,6,6-tetramethylpiperidine polycondensate, tetrakis (2,2,6,6-tetramethyl- 4-piperidyl) -1,2,3,4-butanetetracarboxylate, poly {[6-[(1,1,3,3-tetramethylbutyl) amino] -1,3,5-triazine-2 4-diyl] [(2,2,6,6-tetramethyl-4-piperidyl) imino] hexamethylene [(2,2,6,6-tetramethyl-4-piperidyl) imino]} and the like. These hindered amine compounds may be used alone or in combination of two or more.

  The LLDPE includes, for example, a heat stabilizer, an antioxidant (anti-aging agent), an ultraviolet absorber, an antifogging agent, an antifogging agent, a lubricant, and the like as long as the object of the present invention is not impaired. It may be contained.

  The heat stabilizer may be any conventionally known heat stabilizer and is not particularly limited. Specific examples include chelators such as metal salts of carboxylic acids, phenolic antioxidants, and organic phosphites. These heat stabilizers may be used alone or in combination of two or more.

  The antioxidant is not particularly limited and may be any conventionally known antioxidant. Usually, there are many which have the effect as the said heat stabilizer, for example, chelators, such as a metal salt of carboxylic acid, a phenolic antioxidant, organic phosphorous acid ester, are mentioned. These heat stabilizers may be used alone or in combination of two or more.

  The UV absorber may be any conventionally known UV absorber and is not particularly limited. For example, benzophenone series, benzotriazole series, salicylic acid ester series, cyanoacrylate series, etc. can be used alone or in admixture of two or more. Specifically, as a benzophenone ultraviolet absorber, 2,4-dihydroxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 2-hydroxy-4-dodecyloxybenzophenone, 2,2′-dihydroxy-4-methoxybenzophenone, As a benzotriazole ultraviolet absorber, such as 2,2'-hydroxy-4,4'-dimethoxybenzophenone, 2-hydroxy-4-methoxy-5-sulfobenzophenone, 2- (2'-hydroxy-5'-tert- Butylphenyl) benzotriazole, 2- (2′-hydroxy-5′-methylphenyl) benzotriazole, 2- (2′-hydroxy-3′-tert-butyl-5-methylphenyl) -5-chlorobenzotriazole, 2- (2'-hydroxy-3 ', 5'-di tert- butylphenyl) -5-chloro-benzotriazole, 2- (2'-hydroxy-3 ', 5'-di -tert- amylphenyl) -5-chloro-benzotriazole, and the like. These ultraviolet absorbers may be used alone or in combination of two or more.

  The antifogging agent may be any conventionally known antifogging agent and is not particularly limited. For example, polyhydric alcohol saturated fatty acid esters such as glycerin stearic acid ester, diglycerin stearic acid ester, polyglycerin stearic acid ester, sorbitol glyceryl stearic acid ester, polyhydric alcohol unsaturated such as glycerin oleic acid ester, diglycerin oleic acid ester Examples include fatty acid esters.

  The anti-fogging agent may be any conventionally known anti-fogging agent and is not particularly limited. For example, surfactants such as silicone-based and fluorine-based can be used. The lubricant may be any conventionally known lubricant and is not particularly limited. Examples thereof include saturated fatty acid amides such as stearic acid amide, unsaturated fatty acid amides such as erucic acid amide and oleic acid amide, and bisamides such as ethylene bis stearic acid amide.

  The LLDPE preferably does not contain inorganic fine particles such as a heat retaining agent. Inorganic fine particles such as heat insulating agents have an action of capturing acidic substances and basic substances contained in chemicals such as fertilizers and agricultural chemicals, and consequently promote deterioration of agricultural films. Therefore, when it is unavoidable to contain inorganic fine particles such as a heat insulating agent, the content of the inorganic fine particles such as the heat insulating agent in the intermediate layer is preferably less than 7% by weight.

The intermediate layer constituting the agricultural film of the present invention needs to have a thickness of 20 μm or more. When the thickness of the intermediate layer is less than 20 μm, the mechanical strength and heat resistance of the obtained agricultural film are insufficient. In addition, the upper limit of the thickness of the said intermediate | middle layer is not specifically limited, What is necessary is just to set suitably in the range which does not deviate from the whole thickness (30-150 micrometers) of the agricultural film of this invention.

  The surface layer (surface facing the inside of the house) constituting the agricultural film of the present invention has a function of preventing the occurrence of fine cracks (cracks) generated on the surface of the agricultural film due to ultraviolet rays, moisture, or the like. Acidic and basic substances such as sulfur and lime-sulfur mixtures that are sprayed as agricultural chemicals penetrate into the cracks on the surface of the agricultural film together with moisture, thereby significantly accelerating the deterioration of the physical properties of the agricultural film.

  The surface layer is made of an ethylene-vinyl acetate copolymer (hereinafter referred to as “EVA”) or an ethylene-methyl methacrylate copolymer (hereinafter referred to as “EMMA”) containing at least one kind of hindered amine compound. It needs to be formed.

  The EVA needs to have a vinyl acetate content of 3 to 7% by weight. When the vinyl acetate content of EVA is less than 3% by weight, the surface layer becomes insufficiently flexible and cannot sufficiently perform the function of preventing the occurrence of fine cracks generated on the surface of the resulting agricultural film. . On the other hand, when the vinyl acetate content of EVA exceeds 7% by weight, a blocking (fusion) phenomenon tends to occur during storage of the resulting agricultural film.

The EVA needs to have an MFR of 0.5 to 4.0 g / 10 min (190 ° C.) measured under the conditions of 190 ° C. and a load of 21.18 N in accordance with JIS K7210. It is preferably 0.8 to 2.0 g / 10 min (190 ° C.).

  When the MFR of the EVA is less than 0.5 g / 10 minutes (190 ° C.), the film formability (productivity) of the agricultural film is hindered. On the other hand, when the MFR of the EVA exceeds 4.0 g / 10 min (190 ° C.), the breaking strength of the surface layer is lowered, and therefore the function of preventing the occurrence of fine cracks generated on the surface of the obtained agricultural film. It will not be enough.

  The EMMA needs to have a methyl methacrylate content of 3 to 7% by weight. When the methyl methacrylate content of EMMA is less than 3% by weight, the flexibility of the surface layer becomes insufficient, and the function of preventing the occurrence of fine cracks generated on the surface of the resulting agricultural film cannot be sufficiently achieved. . On the other hand, when the methyl methacrylate content of EMMAA exceeds 7% by weight, a blocking (fusion) phenomenon tends to occur during storage of the resulting agricultural film.

  The EMMA needs to have an MFR of 0.5 to 10.0 g / 10 minutes (190 ° C.) measured under the conditions of 190 ° C. and a load of 21.18 N in accordance with JIS K7210. It is preferably 0.8 to 5.0 g / 10 min (190 ° C.). When the MFR of the EMMA is less than 0.5 g / 10 min (190 ° C.), the film formability (productivity) of the agricultural film is hindered. On the other hand, when the MFR of the EMMA exceeds 10.0 g / 10 min (190 ° C.), the breaking strength of the surface layer is lowered, and thus the function of preventing the occurrence of fine cracks generated on the surface of the obtained agricultural film. It will not be enough.

  The EVA or EMMA needs to contain at least one hindered amine compound. By containing at least one kind of hindered amine compound in EVA or EMMA, the weather resistance and agricultural chemical resistance of the resulting agricultural film are remarkably improved.

  The hindered amine compound may be any conventionally known hindered amine compound, and is not particularly limited. Specifically, the same hindered amine compound as that contained in the intermediate layer may be mentioned. These may be used alone or in combination of two or more.

  The EVA or EMMA needs to contain 0.2 to 5 parts by weight of a nonionic surfactant with respect to 100 parts by weight of the resin in order to cause the condensed water droplets to flow quickly. When the addition amount of the nonionic surfactant is less than 0.2 parts by weight, the effect of causing the condensed water droplets to flow does not continue. On the other hand, when the addition amount of the nonionic surfactant exceeds 5 parts by weight, additives such as hindered amine compounds added to the same surface layer migrate to the surface of the agricultural film together with the antifogging agent, The weather resistance of agricultural films, especially the durability of weather resistance over a long period of time, will be reduced. The nonionic surfactant may be any conventionally known nonionic surfactant, and is not particularly limited. Specifically, the same nonionic surfactant (antifogging agent) as that contained in the intermediate layer may be mentioned. These may be used alone or in combination of two or more.

  In the above EVA or EMMA, if necessary, for example, a heat stabilizer, an antioxidant, an ultraviolet absorber, and the like that may be contained in the intermediate layer, as long as the achievement of the object of the present invention is not inhibited. An antifogging agent, a lubricant, etc., and any conventionally known additive (compounding agent) may be contained.

  However, it is preferable that the EEVA or EMMA does not contain inorganic fine particles such as a heat retaining agent or an anti-blocking agent. As described above, inorganic fine particles such as heat retention agents and anti-blocking agents have the action of capturing acidic and basic substances in chemicals such as fertilizers and agricultural chemicals, and as a result, promote the deterioration of agricultural films. Or the transparency of the surface layer and thus the agricultural film. Therefore, when it is unavoidable to contain inorganic fine particles such as a heat retaining agent or an anti-blocking agent, the content of the inorganic fine particles such as a heat retaining agent or an anti-blocking agent in the surface layer should be as small as possible. It is preferable.

  The surface layer constituting the agricultural film of the present invention needs to have a thickness of 5 μm or more. When the thickness of the surface layer is less than 5 μm, the function of preventing generation of fine cracks generated on the surface of the agricultural film due to ultraviolet rays, moisture, or the like cannot be sufficiently achieved. In addition, the upper limit of the thickness of the said surface layer is not specifically limited, What is necessary is just to set suitably in the range which does not deviate from the whole thickness (30-150 micrometers) of the agricultural film of this invention.

  In the agricultural film of the present invention, the surface layer made of EVA or EMMA is laminated on at least one side of the intermediate layer made of LLDPE, and the layer made of EVA or EMMA is stretched so as to face the inside of the house. It is necessary to However, the LLDPE layer may be laminated on the other surface (the surface facing the outside of the house) of the intermediate layer made of LLDPE, or a layer made of EVA or EMMA may be laminated.

  The agricultural film of the present invention needs to have a total thickness of 30 to 150 μm, preferably 50 to 100 μm. If the total thickness of the agricultural film is less than 30 μm, the absolute mechanical strength of the agricultural film becomes insufficient, and it can be easily broken by mechanical forces such as strong winds. The general weather resistance becomes insufficient, and the mechanical strength is significantly lowered due to the progress of deterioration. On the other hand, if the total thickness of the agricultural film exceeds 150 μm, the weight per unit area of the agricultural film becomes excessive, and it becomes difficult to perform the expansion work on an inclined surface such as a hilly area. Cost per unit area increases, which is economically disadvantageous.

The agricultural film production method (film formation method) of the present invention may be any conventionally known film production method, and is not particularly limited. For example, a multilayer inflation method, a multilayer T-die extrusion method, a multilayer Examples thereof include an extrusion laminating method and a multilayer calendering method.

  The use of the agricultural film of the present invention is not particularly limited, and for example, it can be suitably used for curtains used in fruit tree cultivation and cultivation facilities (agricultural houses) on inclined surfaces such as the hilly terrain. It can be suitably used in fields where light weight and high mechanical strength are required, and fields where chemicals such as fertilizers and agricultural chemicals are unavoidably attached to agricultural films. For example, rain prevention at a composting plant corresponds to the above field.

The agricultural film of the present invention contains at least one or more hindered amine compounds, has a density of 0.90 to 0.93 g / cm ³ , and an MFR of 0.5 to 4.0 g / 10 min (190 ° C. ) From EVA having a vinyl acetate content of 3 to 7% by weight and an MFR of 0.5 to 4.0 g / 10 min (190 ° C.) on both sides of an intermediate layer made of LDPE and having a thickness of 20 μm or more. Since the surface layer with a thickness of 5 μm or more is laminated and the total thickness is 30 to 150 μm, mechanical strength, weather resistance, heat resistance, chemical resistance, stretching workability, blocking resistance, etc. It can be suitably used even in a harsh environment such as fruit tree cultivation on an inclined surface such as a hilly area.

The agricultural film of the present invention contains at least one or more hindered amine compounds, has a density of 0.90 to 0.93 g / cm ³ , and has a melt mass flow rate (MFR) of 0.5 to 4.0 g / The methyl methacrylate content is 3 to 7% by weight and the MFR is 0.5 to 10.0 g / 10 min on both surfaces of the intermediate layer having a thickness of 20 μm or more, which is made of a low density polyethylene resin that is 10 minutes (190 ° C.). Since a surface layer of an ethylene-methyl methacrylate copolymer (190 ° C.) having a thickness of 5 μm or more is laminated and the total thickness is 30 to 150 μm, mechanical strength, weather resistance, heat resistance It is excellent in chemical resistance, spreading workability, blocking resistance, etc., and can be suitably used even in harsh usage environments represented by fruit tree cultivation on inclined surfaces such as hills.

The agricultural film of the present invention contains at least one or more hindered amine compounds, has a density of 0.90 to 0.93 g / cm ³ , and a melt mass flow rate (MFR) of 0.5 to 4.0 g / At least one hindered amine compound is contained on at least one side of the intermediate layer comprising a linear low density polyethylene resin having a thickness of 20 μm or more for 10 minutes (190 ° C.), and the vinyl acetate content is 3 to 3. A surface layer having a thickness of 5 μm or more made of an ethylene-vinyl acetate copolymer having 7% by weight and MFR of 0.5 to 4.0 g / 10 minutes (190 ° C.) is laminated, and the total thickness is 30 It is excellent in mechanical strength, weather resistance, heat resistance, chemical resistance, spreading workability, resistance to blocking, etc. because it is ˜150 μm, and is typically used for fruit tree cultivation on inclined surfaces such as hills. It can be suitably used even under Do use environment.

The agricultural film of the present invention contains at least one or more hindered amine compounds, has a density of 0.90 to 0.93 g / cm ³ , and a melt mass flow rate (MFR) of 0.5 to 4.0 g / At least one hindered amine compound is contained on at least one side of an intermediate layer comprising a linear low density polyethylene resin having a thickness of 20 μm or more for 10 minutes (190 ° C.), and the content of methyl methacrylate is 3 to 3. A surface layer having a thickness of 5 μm or more made of an ethylene-methyl methacrylate copolymer having 7% by weight and MFR of 0.5 to 4.0 g / 10 min (190 ° C.) is laminated, and the total thickness is 30 Excellent mechanical strength, weather resistance, heat resistance, chemical resistance, stretch workability, anti-blocking, etc. due to ˜150 μm. It can be suitably used even in harsh environments typified by cultivation.

  In the agricultural film of the present invention, 0.2 to 5 parts by weight of nonionic surfactant is added to the surface layer with respect to 100 parts by weight of the resin component, so mechanical strength, weather resistance, heat resistance, chemical resistance It can be suitably used even under harsh usage environments typified by fruit tree cultivation on inclined surfaces such as hills.

  In order to describe the present invention in more detail, examples are given below, but the present invention is not limited to these examples.

(Examples 1 and 2) and (Comparative Examples 1 to 3)
A film having the structure shown in Table 1 was co-extruded in three layers by an inflation molding method to produce each agricultural film having a total thickness of 60 μm.

  The performance (1. blocking resistance, 2. shrinkage resistance, 3. chemical resistance, 4. strength at break) of each agricultural film obtained above was evaluated by the following methods. The results are shown in Table 1.

1. Blocking resistance 10 agricultural films cut to 10 cm x 10 cm are stacked, left in an oven at 80 ° C for 6 hours, then taken out, and the blocking state (fused state) between the agricultural films is checked sensuously. The blocking resistance was evaluated according to the following criteria.
[Criteria]
○ ... No blocking between agricultural films is observed, and all films peel off easily.
I was able to.
△ ... A little blocking between agricultural films is observed, but it can be peeled off without hindrance.
I was able to.
×… Agricultural films are partially or completely blocked and peel off
I couldn't.

2. Shrinkage resistance Agricultural film cut to 30 cm in length x 30 cm in width was left in an oven at 50 ° C for 1 month, then taken out, measured for length in the vertical and horizontal directions, and the shrinkage in each direction was determined. The shrinkage resistance was evaluated according to the following criteria based on the value obtained and the value with the larger shrinkage.
[Criteria]
○ The shrinkage rate was less than 0.5%.
Δ: Shrinkage was 0.5% or more and less than 1.0%.
X The shrinkage rate was 1.0% or more.

3. Chemical resistance An agricultural film cut to 15 cm × 15 cm was immersed in 1N sulfuric acid for 7 days, then taken out and irradiated with 50 W / m ² of ultraviolet light for 48 hours by an ultraviolet lamp. Next, in accordance with JIS K 6781 “Agricultural Polyethylene Film”, the elongation at break of the agricultural film after irradiation with ultraviolet rays was measured, and the chemical resistance was evaluated according to the following criteria.
[Criteria]
○ The residual elongation at break was 500% or more.
Δ: The residual elongation at break was 200% or more and less than 500%.
× The residual elongation at break was less than 200%.

4). Breaking point strength Using a strograph (manufactured by Toyo Seiki Seisakusho Co., Ltd.), the breaking point strength of the agricultural film was measured according to JIS K 6781, and the breaking point strength was evaluated according to the following criteria.
[Criteria]
○ The strength at break was 24.5 N or more.
Δ: The strength at break was 14.7 N or more and less than 24.5 N.
X: The strength at break was less than 14.7N.

  As is apparent from Table 1, the agricultural films of Example 1 and Example 2 according to the present invention all have good or excellent performance in all of blocking resistance, shrinkage resistance, chemical resistance and breaking strength. Expressed.

  On the other hand, the agricultural film of Comparative Example 1 in which the surface layer was formed of EVA having a vinyl acetate content exceeding 7% by weight (10% by weight) had poor blocking resistance. In addition, the agricultural film of Comparative Example 2 in which the surface layer was formed of LDPE without using EVA and the agricultural film of Comparative Example 3 in which the surface layer was formed of LLDPE had poor chemical resistance.

(Example 3) and (Comparative Example 4 to Comparative Example 6)
A film having the structure shown in Table 2 was co-extruded in three layers by an inflation molding method to produce each agricultural film having a total thickness of 60 μm.

  The performance (1. blocking resistance, 2. shrinkage resistance, 3. chemical resistance, 4. strength at break) of each agricultural film obtained above was evaluated by the above method. The results are shown in Table 2.

As is clear from Table 2, the agricultural film of Example 3 according to the present invention exhibited good or excellent performance in all of blocking resistance, shrinkage resistance, chemical resistance and breaking strength.

  On the other hand, the agricultural film of Comparative Example 4 in which the intermediate layer was formed of EVA having a low vinyl acetate content (5% by weight) had poor shrinkage resistance. Moreover, the agricultural film of Comparative Example 5 in which the intermediate layer was formed of EVA having a high vinyl acetate content (15 wt%) had poor shrinkage resistance and strength at break. Furthermore, the agricultural film of Comparative Example 6 in which the intermediate layer was formed of EVA and the surface layer was formed of LDPE had poor shrinkage resistance and chemical resistance.

(Example 4 and Example 5) and (Comparative Example 7 to Comparative Example 9)
A film having the structure shown in Table 3 was co-extruded into three layers by an inflation molding method to produce each agricultural film having a total thickness of 60 μm.

  The performance (1. blocking resistance, 2. shrinkage resistance, 3. chemical resistance, 4. strength at break) of each agricultural film obtained above was evaluated by the above method. The results are shown in Table 3.

As is apparent from Table 3, the agricultural films of Example 4 and Example 5 according to the present invention all have good or excellent performance with respect to all of blocking resistance, shrinkage resistance, chemical resistance and breaking strength. Expressed.

  On the other hand, the agricultural film of Comparative Example 7 in which no surface layer was provided had poor chemical resistance. Moreover, the agricultural film of Comparative Example 8 in which no intermediate layer was provided had poor shrinkage resistance and breaking strength. Furthermore, the agricultural film of Comparative Example 9 in which the thickness of the intermediate layer was less than 20 μm (15 μm) had poor shrinkage resistance.

(Example 6 to Example 10)
A film having the structure shown in Table 4 was co-extruded in three layers by an inflation molding method to produce each agricultural film having a total thickness of 60 μm.

  The performance (1. blocking resistance, 2. shrinkage resistance, 3. chemical resistance, 4. strength at break) of each agricultural film obtained above was evaluated by the following methods. The results are shown in Table 4.

(Comparative Example 10 to Comparative Example 15)
A film having the configuration shown in Table 5 was co-extruded in three layers by an inflation molding method to produce each agricultural film having a total thickness of 60 μm.

  The performance (1. blocking resistance, 2. shrinkage resistance, 3. chemical resistance, 4. strength at break) of each agricultural film obtained above was evaluated by the above method. The results are shown in Table 5.

  As is apparent from Table 4, the agricultural films of Examples 6 to 10 according to the present invention all have good or excellent performance with respect to all of blocking resistance, shrink resistance, chemical resistance and breaking strength. Expressed.

  On the other hand, as apparent from Table 5, the agricultural film of Comparative Example 10 in which the surface layer was formed of EMMA having a methyl methacrylate content exceeding 7% by weight (10% by weight) had poor blocking resistance. It was. Moreover, the agricultural film of the comparative example 11 which formed the surface layer with LDPE, the agricultural film of the comparative example 12 which formed the surface layer with LLDPE, and the comparative example 13 which did not provide the surface layer? All of the agricultural films had poor chemical resistance. Further, the agricultural film of Comparative Example 13 in which the intermediate layer was formed with EMMA having a low methyl methacrylate content (5 wt%) and the agricultural film of Comparative Example 15 in which the thickness of the intermediate layer was less than 20 μm (15 μm) All of them had poor shrinkage resistance. Further, the agricultural film of Comparative Example 14 in which the intermediate layer was formed with EMMA having a high methyl methacrylate content (15 wt%) and the agricultural film of Comparative Example 14 in which the intermediate layer was not provided were both shrink resistant and fractured. The point intensity was poor. Furthermore, the agricultural film of Comparative Example 15 in which the intermediate layer was formed with EMMA and the surface layer was formed with LDPE had poor shrinkage resistance and chemical resistance.

(Examples 11-14 and Comparative Examples 16-18)
A film having the structure shown in Table 6 was subjected to three-layer coextrusion molding by an inflation molding method to obtain an agricultural film. The total thickness of each film was the same as shown in the table. About the obtained film, the result (1. blocking resistance, 2. shrinkage resistance, 3. chemical resistance, 4. strength at break) of each agricultural film was evaluated by the above-mentioned method. . The MFR shown in the table is a value measured at a temperature of 190 ° C. and a load of 21.18 N in accordance with JIS K-7210.

Examples 11 and 12 showed good evaluation results over all items. Further, in Examples 13 and 14, when the vinyl acetate content of EVA or the methyl methacrylate content of EMMA in the surface layer was increased, the blocking resistance and shrinkage resistance were slightly lowered, but the evaluation results were generally good. It was. In Comparative Example 16, when the vinyl acetate content was further increased, the blocking resistance was lowered. In Comparative Examples 17 and 18, although LDPE and LLDPE were arranged on the surface layer, the evaluation results showed that the pesticide resistance was lowered.

(Examples 15 and 16 and Comparative Examples 19 to 23)
A film having the structure shown in Table 7 was three-layer coextruded by an inflation molding method to obtain an agricultural film. The total thickness of each film was the same as shown in the table. About the obtained film, the performance (1. blocking resistance, 2. shrinkage resistance, 3. chemical resistance, 4. strength at break) of each agricultural film was evaluated by the above method, and the results are shown in Table 7. .

In Examples 15 and 16, since the density of the linear low-density polyethylene used for the intermediate layer was lowered, the evaluation of shrinkage was slightly lowered, but generally good results were obtained. In Comparative Examples 19 to 23, when an ethylene-vinyl acetate copolymer or an ethylene-methyl methacrylate copolymer was disposed in the intermediate layer, the evaluation of shrinkage was mainly deteriorated. In Comparative Example 22, since the low density polyethylene resin was disposed on the surface layer, the agrochemical resistance was also lowered. Further, in Comparative Example 23, an ethylene-vinyl acetate copolymer was disposed in the intermediate layer, and an ethylene-methyl methacrylate copolymer was disposed in the surface layer, but the shrinkage and strength at break were poorly evaluated.

(Examples 17-19 and Comparative Examples 24-27)
A film having the structure shown in Table 8 was three-layer coextruded by an inflation molding method to obtain an agricultural film. About the obtained film, the performance (1. blocking resistance, 2. shrinkage resistance, 3. chemical resistance, 4. strength at break) of each agricultural film was evaluated by the above method, and the results are shown in Table 8. .
In Example 17, since the thickness of the surface layer was reduced and the thickness of the intermediate layer was increased, the evaluation of chemical resistance was slightly lowered, but the result was generally good. In Examples 18 and 19, on the contrary, the surface layer was thickened and the intermediate layer was thinned. Therefore, the evaluation of blocking resistance, shrinkage resistance, chemical resistance, and strength at break was slightly lowered, but generally good results were obtained. It was. When Comparative Examples 24 to 26 were evaluated using LLDPE alone, EVA alone, and EMMA alone, LLDPE significantly decreased chemical resistance, and EVA and EMMA significantly decreased shrinkage resistance and breaking strength. In Comparative Example 26, since the intermediate layer was extremely thin and the surface layer was thick, the evaluation of shrinkage resistance was greatly deteriorated.

  As described above, the agricultural film of the present invention exhibits excellent blocking resistance, shrinkage resistance, chemical resistance, strength at break, mechanical strength, weather resistance, heat resistance, chemical resistance, stretching work For example, it can be used suitably for fruit tree cultivation on inclined surfaces such as hills, but also fertilizers such as curtains used in agricultural houses and rain guards for composting plants, etc. It can also be suitably used in fields where chemicals such as agricultural chemicals are unavoidably attached to agricultural films, and fields that require light weight and high mechanical strength.

Claims (5)

At least one or more hindered amine compounds are contained, the density is 0.90 to 0.93 g / cm ³ , and the melt mass flow rate (MFR) is 0.5 to 4.0 g / 10 minutes (190 ° C.). Ethylene having a vinyl acetate content of 3 to 7% by weight and an MFR of 0.5 to 4.0 g / 10 min (190 ° C.) on both sides of an intermediate layer comprising a low density polyethylene resin having a thickness of 20 μm or more An agricultural film comprising a surface layer made of a vinyl acetate copolymer and having a thickness of 5 μm or more laminated, and an overall thickness of 30 to 150 μm. At least one or more hindered amine compounds are contained, the density is 0.90 to 0.93 g / cm ³ , and the melt mass flow rate (MFR) is 0.5 to 4.0 g / 10 minutes (190 ° C.). Ethylene having a methyl methacrylate content of 3 to 7% by weight and an MFR of 0.5 to 10.0 g / 10 min (190 ° C.) on both surfaces of an intermediate layer comprising a low density polyethylene resin having a thickness of 20 μm or more. An agricultural film comprising a surface layer having a thickness of 5 μm or more made of a methyl methacrylate copolymer and having an overall thickness of 30 to 150 μm. At least one or more hindered amine compounds are contained, the density is 0.90 to 0.93 g / cm ³ , and the melt mass flow rate (MFR) is 0.5 to 4.0 g / 10 minutes (190 ° C.). At least one kind of hindered amine compound is contained on at least one side of the intermediate layer comprising a linear low density polyethylene resin having a thickness of 20 μm or more, the vinyl acetate content is 3 to 7% by weight, and the MFR is 0.1. 5 to 4.0 g / 10 min (190 ° C.) of an ethylene-vinyl acetate copolymer having a thickness of 5 μm or more is laminated, and the total thickness is 30 to 150 μm. Agricultural film. At least one or more hindered amine compounds are contained, the density is 0.90 to 0.93 g / cm ³ , and the melt mass flow rate (MFR) is 0.5 to 4.0 g / 10 minutes (190 ° C.). At least one hindered amine compound is contained on at least one side of the intermediate layer comprising a linear low density polyethylene resin having a thickness of 20 μm or more, the methyl methacrylate content is 3 to 7% by weight, and the MFR is 0.1. 5 to 4.0 g / 10 min (190 ° C.) of an ethylene-methyl methacrylate copolymer and a surface layer having a thickness of 5 μm or more is laminated, and the total thickness is 30 to 150 μm. Agricultural film.   The agricultural film according to claim 3, wherein 0.2 to 5 parts by weight of a nonionic surfactant is added to 100 parts by weight of the resin component of the surface layer.