JP2010081813A - Agricultural film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an agricultural film suitably usable under sever environment typified by fruit tree cultivation on a slanted surface of a hilly area or the like. <P>SOLUTION: The agricultural film includes: an intermediate layer having a prescribed thickness and comprising straight-chain low-density polyethylene having a density of 0.915-0.930 g/cm<SP>3</SP>and a melt flow rate of 0.5-4.0 g/10 min, and a hindered amine compound having at least two piperidine ring structures in molecules and a number average molecular weight of ≥1,000; and an outer layer having a prescribed thickness and comprising ethylene-vinyl acetate copolymer having the content of a vinyl acetate component of 5-15 wt.% and a melt flow rate of 0.5-4.0 g/10 min. The film has a prescribed thickness of 30-150 μm wherein the thickness of the intermediated layer accounts for 50-90% in the thickness of the whole of the film, and at least one layer of the intermediate layer or the outer layer contains a prescribed amount of mica having a prescribed average particle diameter. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to an agricultural film.

  Conventionally, polyvinyl chloride resin agricultural films (hereinafter referred to as “PVC agricultural films”) and polyethylene resin agricultural films (hereinafter referred to as “PO”) are used as agricultural films used for the cultivation of agricultural crops. Etc.) are generally used.

  Agricultural film, when used outdoors, 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, Are exposed to degradation factors due to acid rain and the like.

  On the other hand, agricultural films are being developed in the direction of thinner film because of the demands for easy covering and spreading work at cultivation facilities, reduction of waste after use, and cost reduction of cultivation facilities. PVC-based agricultural films are excellent in heat retention, weather resistance, transparency, workability, etc., but the use of toxic gases has been reduced in recent years due to concerns about the generation of toxic gases during incineration after use. Yes.

  On the other hand, recently, the use of PO-based agricultural films has been rapidly increasing as agricultural films that replace PVC-based agricultural films. The PO agricultural film has many advantages over the PVC agricultural film, such as light weight, price, processability, mechanical strength, and easy disposal.

  However, the PO agricultural film has a more fragile aspect than the PVC agricultural film for the deterioration factors in outdoor and indoor use. Various studies have been made to enable local use.

  Specifically, Patent Document 1 discloses a polyolefin containing a hindered amine compound as a stabilizer as a method for improving the resistance of the PO agricultural film to the deterioration factor.

  However, the polyolefin has a problem that, for example, when it is formed into a film, the hindered amine compound easily disappears in a short period under the condition that moisture is involved, and the efficacy of the hindered amine compound easily disappears in a short period.

In Patent Document 2, as a film capable of sustaining the efficacy of a hindered amine compound, 0.1 to ² % by weight of a hindered amine compound and an inorganic fine powder having a surface area of 10 m ² / g or more and having a polarity of 0.5 to 20 are used. A thermoplastic synthetic resin film having excellent weather resistance and containing wt% is disclosed.

  However, since the thermoplastic synthetic resin film contains both a hindered amine compound and an inorganic fine powder, the transparency is remarkably lowered, and there is a problem that it is not suitable for use as an agricultural film. .

  Further, Patent Document 3 discloses a copolymer of vinyl acetate and olefin or a mixture of the copolymer and polyolefin, in which 100 wt parts of olefin resin having a vinyl acetate content of 10 to 20 wt% with respect to the whole. On the other hand, (A) 1-20 parts by weight of lithium aluminum composite hydroxide salt, (B) 0.05-3 parts by weight of hindered amine light stabilizer and (C) 1-4 parts by weight of antifogging agent The content ratio of vinyl acetate to the whole with a polyolefin, a copolymer of vinyl acetate and olefin, or a mixture of the copolymer and polyolefin, on one or both sides of a substrate layer having a thickness of 30 to 180 μm Agricultural olefin resin films provided with a coating layer having a thickness of 10 to 50 μm, comprising an olefin resin comprising 9% by weight or less of resin is disclosed. The

  However, fruit tree cultivation, especially grape cultivation, is often carried out in hilly areas, and tension is concentrated on high altitudes in agricultural films stretched on slopes. Also, the slope facing south has a large amount of ultraviolet light per unit area, and the air below the agricultural film heated by sunlight rises along the slope, and the upper part of the cultivation facility becomes high temperature. In addition, in viticulture, it is routine to spray a strongly basic lime-sulfur mixture with a large amount of dilution water. In order to use the PO-based agricultural film under such severe conditions, mechanical strength, weather resistance and agricultural chemical resistance are insufficient.

  Furthermore, in the cultivation of fruit trees represented by grapes in hilly areas, it is necessary to sufficiently transmit sunlight, but it is also necessary to suppress the transmission of direct rays from the sun, so it is necessary to incorporate a lot of scattered light .

  This is because problems such as poor growth of crops occur when the amount of sunlight is insufficient. However, even if a large amount of sunlight is taken in, if there is a lot of direct light, the temperature inside the house will rise more than necessary in fruit tree cultivation, and the leaf burning phenomenon (the temperature will suddenly add to the leaves and the leaves will burn) Or the like, or there is a problem that uneven distribution of transmitted light occurs in the cultivation facility.

  In order to solve this problem, Patent Document 4 discloses that the film is colored white or purple so that the amount of direct light transmitted is suppressed, and problems such as leaf burning due to rapid temperature rise in the cultivation facility are prevented. A method is disclosed. However, in this method, the amount of sunlight is also reduced, which may cause problems such as poor growth of crops.

JP 59-86645 A JP-A-56-41254 JP 7-312996 A Japanese Patent Publication No.57-51861

  The present invention provides an agricultural film that can be suitably used even in a harsh use environment typified by fruit tree cultivation on an inclined surface such as a hilly area.

The agricultural film of the present invention comprises a linear low-density polyethylene having a density of 0.915 to 0.930 g / cm ³ and a melt flow rate of 0.5 to 4.0 g / 10 min. An intermediate layer having a thickness of 20 μm or more containing a hindered amine compound having two or more piperidine ring structures in the molecule and having a number average molecular weight of 1000 or more; Including an outer layer having a thickness of 5 μm or more containing an ethylene-vinyl acetate copolymer having a vinyl component content of 5 to 15% by weight and a melt flow rate of 0.5 to 4.0 g / 10 min. The thickness of the intermediate layer is 30 to 150 μm, the thickness of the intermediate layer is 50 to 90% of the total thickness, and at least one of the intermediate layer and the outer layer has an average particle diameter of 5 to 40 μm. And the total amount of mica is 0.1 to 5 parts by weight with respect to 100 parts by weight of the total amount of synthetic resin. In Formula 1, R ₁ represents a functional group or compound (including oligomers and polymers) having 1 or more carbon atoms and containing at least one methylene group.

式１中において、Ｒ₁は、炭素数が１以上で且つ少なくとも１以上のメチレン基を含む官能基又は化合物（オリゴマー、ポリマーを含む）を表す。

During formula 1, R ₁ is represents a functional group or compound containing and at least one or more methylene groups in one or more carbon atoms (including oligomer and polymer).

  The intermediate layer of the agricultural film of the present invention is softened by the mechanical strength that can withstand the tension applied to the cultivation facility on an inclined surface such as a hilly terrain and the partially heated temperature state. To prevent.

The intermediate layer contains, as a main component, linear low-density polyethylene having a density of 0.915 to 0.930 g / cm ³ and a melt flow rate of 0.5 to 4.0 g / 10 minutes. . In the present invention, the main component means that it accounts for 50% by weight or more of the total amount of the synthetic resin constituting the layer.

If the density of the linear low-density polyethylene constituting the intermediate layer is low, the molding stability of the agricultural film is lowered, and if it is high, the tear strength of the agricultural film is lowered. limited to ^{.930g / cm 3, 0.917~0.925g / cm} 3 are preferred. The density of the linear low density polyethylene refers to a value measured in accordance with JIS K7112 “Plastic—Method for measuring density and specific gravity of non-foamed plastic”.

  Moreover, when the melt flow rate (MFR) of the linear low density polyethylene constituting the intermediate layer is low, the molding stability of the agricultural film is lowered, and when it is high, the mechanical strength of the agricultural film is lowered. Therefore, it is limited to 0.5 to 4.0 g / 10 minutes, and 0.8 to 2.5 g / 10 minutes is preferable. In addition, the melt flow rate of linear low-density polyethylene is a temperature of 190 ° C. and a load in accordance with JIS K7210 “Testing method for melt flow rate (MFR) and melt volume flow rate (MVR) of plastic-thermoplastic plastic”. The value measured under the condition of 21.18N.

  Furthermore, it is preferable that the intermediate layer does not contain low density polyethylene. This is because when the intermediate layer contains low density polyethylene, the mechanical strength of the agricultural film is lowered. In addition, when it is unavoidable to contain low density polyethylene in an intermediate layer, 30 parts by weight or less of low density polyethylene is preferable with respect to 100 parts by weight of linear low density polyethylene constituting the intermediate layer.

Further, the intermediate layer contains a hindered amine compound having two or more piperidine ring structures represented by the following formula 1 in the molecule and having a number average molecular weight of 1000 or more. In Formula 1, R ₁ represents a functional group or compound having 1 or more carbon atoms and containing at least one methylene group. The compound having 1 or more carbon atoms and containing at least one methylene group includes oligomers and polymers. Specifically, examples of R ₁ include a propyl group. By including the hindered amine compound having such a specific structure, the agricultural film has excellent durability against chemicals such as agricultural chemicals, and deterioration factors caused by acid rain. Become.

  In addition, the hindered amine compound which has two or more piperidine ring structures represented by Formula 1 in a molecule | numerator is marketed by the brand name "Tinvin NOR 371" from Ciba Japan.

  The hindered amine compound is a polymer compound, but if the number average molecular weight of the hindered amine compound is low, bleeding out tends to occur and the durability of the effect decreases, so it is limited to 1000 or more, and preferably 2000 to 5000.

  The intermediate layer may contain a hindered amine compound other than the hindered amine compound having two or more piperidine ring structures represented by the formula 1 in the molecule and having a number average molecular weight of 1000 or more. Examples of hindered amine compounds include dimethyl-1- (2-hydroxyethyl) succinate-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-piperidi) ) Imino]}, and the like.

  If the thickness of the intermediate layer is thin, the mechanical strength and heat resistance of the agricultural film are lowered, so it is limited to 20 μm or more, and preferably 30 to 80 μm.

  In the agricultural film of the present invention, outer layers are laminated and integrated on both surfaces of the intermediate layer. In addition, the outer layer laminated and integrated on both surfaces of the intermediate layer may be the same in composition or different from each other. This outer layer prevents the occurrence of fine cracks (cracks) on the surface of the agricultural film due to ultraviolet rays or moisture.

  When cracks occur on the surface of agricultural films, acidic and basic substances such as sulfur and lime-sulfur mixtures that are sprayed as pesticides penetrate through the cracks with moisture, significantly accelerating the deterioration of the physical properties of agricultural films. .

  Therefore, in the agricultural film of the present invention, the outer layer has an ethylene-vinyl acetate copolymer having a vinyl acetate component content of 5 to 15% by weight and a melt flow rate of 0.5 to 4.0 g / 10 min. Contains coalesce as a main component.

  If the content of the vinyl acetate component in the ethylene-vinyl acetate copolymer constituting the outer layer is small, the flexibility of the outer layer is reduced and the occurrence of fine cracks occurring on the surface of agricultural films is prevented. However, if the amount is too large, the agricultural film is likely to be blocked. Therefore, the amount is limited to 5 to 15% by weight, and preferably 7 to 10% by weight.

  Further, if the melt flow rate of the ethylene-vinyl acetate copolymer constituting the outer layer is low, the moldability of the agricultural film is lowered, and if it is high, the breaking strength of the outer layer is lowered, and the surface of the agricultural film is reduced. Since it is not possible to prevent the occurrence of fine cracks, the thickness is limited to 0.5 to 4.0 g / 10 minutes, and preferably 0.8 to 2.0 g / 10 minutes. The melt flow rate of the ethylene-vinyl acetate copolymer is 190 ° C. in accordance with JIS K7210 “Testing method for melt flow rate (MFR) and melt volume flow rate (MVR) of plastic-thermoplastic plastic”. The value measured under the condition of load 21.18N.

  When producing agricultural films by the coextrusion method, the melt flow rate of linear low-density polyethylene constituting the intermediate layer and the melt of ethylene-vinyl acetate copolymer constituting the outer layer The flow rate is preferably set to a value close to each other.

  If the thickness of the outer layer is thin, generation of fine cracks generated on the surface of the agricultural film due to ultraviolet rays or moisture cannot be prevented, so it is limited to 5 μm or more, and preferably 10 to 25 μm.

  In the agricultural film of the present invention, mica is contained in at least one of the intermediate layer and the outer layer, and mica may be contained only in one or two of the intermediate layer and the outer layer. In addition, mica may be contained in all of the intermediate layer and the two outer layers. In order to improve the scattered light transmittance of the agricultural film, it is preferable that mica is contained in the two outer layers.

  The kind of mica is not limited and may be natural mica or synthetic mica. The average particle diameter of mica makes both the scattered light transmittance and the total light transmittance good, and can also prevent a decrease in mechanical strength such as tear strength and breaking strength of agricultural films. It is limited to 40 μm, more preferably 10 to 30 μm, and particularly preferably 15 to 20 μm.

  The content of mica in the agricultural film should make both the scattered light transmittance and the total light transmittance good, and prevent the mechanical strength such as tear strength and breaking strength of the agricultural film from being lowered. Therefore, the amount is limited to 0.1 to 5 parts by weight with respect to 100 parts by weight of the total amount of the synthetic resin constituting the agricultural film.

  Furthermore, an antioxidant, an ultraviolet absorber, an antifogging agent, an antifoggant, a lubricant, a pigment, and the like may be added to the agricultural film as long as the physical properties thereof are not impaired.

  Although it does not specifically limit as antioxidant, What has the effect as a heat stabilizer is preferable. Examples of such antioxidants include chelators such as metal salts of carboxylic acids, phenolic antioxidants, and organic phosphites. Antioxidants may be used alone or in combination of two or more.

  The ultraviolet absorber is not particularly limited, and examples thereof include benzophenone ultraviolet absorbers, benzotriazole ultraviolet absorbers, salicylic acid ester ultraviolet absorbers, cyanoacrylate ultraviolet absorbers, and the like. Two or more kinds may be used in combination.

  Examples of the benzophenone ultraviolet absorber include 2,4-dihydroxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 2-hydroxy-4-dodecyloxybenzophenone, 2,2′-dihydroxy-4-methoxybenzophenone, 2 , 2'-hydroxy-4,4'-dimethoxybenzophenone, 2-hydroxy-4-methoxy-5-sulfobenzophenone, and the like.

  Examples of the benzotriazole ultraviolet absorber include 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-chlorobenzotriazole 2- (2′-hydroxy-3,5′-di-tert-amylphenyl) -5-chlorobenzotriazole and the like.

  The antifogging agent is not particularly limited. For example, polyglycerin stearic acid ester, diglycerin stearic acid ester, polyglycerin stearic acid ester, polyhydric alcohol saturated fatty acid ester such as sorbitol glyceryl stearic acid ester, glycerin oleic acid ester, di Examples thereof include polyhydric alcohol unsaturated fatty acid esters such as glycerin oleate.

  The anti-fogging agent is not particularly limited, and examples thereof include silicone-based and fluorine-based surfactants. The lubricant is not particularly limited, and 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.

  However, it is preferable that the agricultural film does not contain, for example, inorganic fine particles such as a heat insulating agent. This is because the inorganic fine particles have an action of capturing acidic substances and basic substances contained in chemicals such as fertilizers and agricultural chemicals, and thus promote deterioration of agricultural films. Therefore, when it is necessary to contain inorganic fine particles in the agricultural film, it is preferable to adjust the content of the inorganic fine particles in the agricultural film to 7% by weight or less.

  And the whole thickness of an agricultural film is limited to 30-150 micrometers, and 50-100 micrometers is preferable. This is because if the agricultural film is thin, the mechanical strength of the agricultural film is reduced, it is easily broken by strong winds, etc. This is because the mechanical strength of the film is significantly reduced. On the other hand, if the agricultural film is thick, the handleability of the agricultural film is lowered, and it may be difficult to extend the agricultural film on an inclined surface such as a hilly area.

  Furthermore, the thickness of the intermediate layer is limited to 50 to 90% of the total thickness of the agricultural film. If the ratio of the thickness of the intermediate layer is low with respect to the total thickness of the agricultural film, the mechanical strength of the agricultural film is reduced, it is easily broken by strong winds, or the weather resistance of the agricultural film is insufficient. This is because the mechanical strength of the agricultural film is significantly reduced due to the progress of deterioration. On the other hand, if the ratio of the thickness of the intermediate layer to the total thickness of the agricultural film is high, it is impossible to prevent the generation of fine cracks (cracks) on the surface of the agricultural film due to ultraviolet rays or moisture. is there.

  Next, the manufacturing method of the agricultural film is demonstrated. The method for producing an agricultural film is not particularly limited. For example, a production apparatus in which a first extruder, a second extruder, and a third extruder are all connected to the same die is prepared, and a linear low density is prepared. Polyethylene and hindered amine compound are supplied to the first extruder, melt kneaded and extruded from the first extruder, and ethylene-vinyl acetate copolymer is supplied to the second extruder and third extruder, melt kneaded and second extruded. Directly extruded from the first extruder by the multilayer inflation method, multilayer T-die extrusion method, multilayer calendar method, etc. Agriculture by laminating and integrating outer layers mainly composed of ethylene-vinyl acetate copolymer extruded from each of the second and third extruders on both sides of the intermediate layer mainly composed of chain-shaped low density polyethylene For fill Method for producing thereof.

  Agricultural films can be used not only for fruit tree cultivation on slopes such as hills, but also for applications that require light weight and high mechanical strength, chemicals such as fertilizers and agricultural chemicals. It can also be suitably used for applications where it is unavoidable to adhere to water, and examples of such applications include use for preventing rain at a composting plant.

  The agricultural film of the present invention is excellent in excellent mechanical strength, weather resistance, heat resistance, and agricultural chemical resistance, and is also excellent in workability for spreading to a cultivation facility. Therefore, the agricultural film can be suitably used even in a harsh use environment typified by fruit tree cultivation on an inclined surface such as a hilly area.

  And since the film for agriculture of the present invention has both high scattered light transmittance and total light transmittance, when used in a cultivation facility, it is cultivated while suppressing direct rays of sunlight into the cultivation facility. It is possible to transmit as much sunlight as possible into the facility, without hindering the growth of crops in the cultivation facility, and to substantially prevent the burning of leaves due to the temperature rise in the cultivation facility.

  Hereinafter, embodiments of the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples.

Example 1
Linear low density polyethylene A (trade name “Daulex 2045G” manufactured by Dow Chemical Co., Ltd., density: 0.920 g / cm ³ , melt flow rate: 1.0 g / 10 min) 100 parts by weight and represented by Formula 1 A first resin composition comprising 0.4 parts by weight of a hindered amine compound A having two or more piperidine ring structures in its molecule (trade name “Tinuvin NOR 371” manufactured by Ciba Japan, number average molecular weight: 3200) is used as the first extruder. In addition, ethylene-vinyl acetate copolymer A (trade name “Novatech LV241” manufactured by Nippon Polyethylene Co., Ltd., density: 0.929 g / cm ³ , melt flow rate: 1.5 g / 10 min, content of vinyl acetate component: 8 % By weight) 100 parts by weight, hindered amine compound A having two or more piperidine ring structures represented by Formula 1 (trade name “Ciba Japan”) A second resin composition comprising 0.4 parts by weight of “inuvin NOR 371”, number average molecular weight: 3200) and 2 parts by weight of mica A (trade name “CBR”, average particle diameter: 18 μm, manufactured by Chuetsu Graphite Industries Co., Ltd.) In a two-extruder, ethylene-vinyl acetate copolymer A (trade name “Novatech LV241” manufactured by Nippon Polyethylene Co., Ltd., density: 0.929 g / cm ³ , melt flow rate: 1.5 g / 10 min, containing vinyl acetate component Amount: 8% by weight), hindered amine compound A having two or more piperidine ring structures represented by formula 1 (trade name “Tinvin NOR 371”, number average molecular weight: 3200, manufactured by Ciba Japan) 0.4 part by weight and mica A third resin composition comprising 2 parts by weight of A (trade name “CBR” manufactured by Chuetsu Graphite Industries Co., Ltd., average particle size: 18 μm) was supplied to the third extruder and dissolved. After kneading, all the first to three extruders are extruded into connected dies, and three-layer coextrusion molding is performed by an inflation method so that the thickness ratio is 10:40:10, and the total thickness is 60 μm. A film was obtained. In addition, the agricultural film has an outer layer made of the second resin composition laminated and integrated on one surface of the intermediate layer made of the first resin composition, and made of the third resin composition on the other surface of the intermediate layer. The outer layer was laminated and integrated.

(Example 2)
Instead of linear low density polyethylene A, linear low density polyethylene B (trade name “Elite 5400” manufactured by Dow Chemical Co., Ltd., density: 0.916 g / cm ³ , melt flow rate: 1.0 g / 10 min) An agricultural film was obtained in the same manner as in Example 1 except that was used.

(Example 3)
Linear low-density polyethylene C instead of linear low-density polyethylene A (trade name “Daulex 2042G” manufactured by Dow Chemical Company, density: 0.930 g / cm ³ , melt flow rate: 1.0 g / 10 min) An agricultural film was obtained in the same manner as in Example 1 except that was used.

Example 4
Instead of ethylene-vinyl acetate copolymer A, ethylene-vinyl acetate copolymer B (trade name “Ultrasen 513” manufactured by Tosoh Corporation, density: 0.928 g / cm) ³ , melt flow rate: 1.0 g / 10 min, content of vinyl acetate component: 5% by weight) was used in the same manner as in Example 1 to obtain an agricultural film.

(Example 5)
In the second and third extruders, instead of ethylene-vinyl acetate copolymer A, ethylene-vinyl acetate copolymer C (trade name “Novatech LV430” manufactured by Nippon Polyethylene Co., Ltd., density: 0.940 g / cm ³ , melt flow rate: 1.0 g / 10 min, content of vinyl acetate component: 15% by weight) was used in the same manner as in Example 1 to obtain an agricultural film.

(Example 6)
The same procedure as in Example 1 was conducted except that mica B (trade name “BF50”, average particle size: 5 μm, manufactured by Chuetsu Graphite Industries Co., Ltd.) was supplied to the second extruder and the third extruder instead of mica A. A film for agriculture was obtained.

(Example 7)
Example 1 except that mica C (trade name “BSP-2” manufactured by Chuetsu Graphite Industries Co., Ltd., average particle size: 40 μm) was supplied to the second extruder and the third extruder instead of mica A. An agricultural film was obtained in the same manner.

(Example 8)
An agricultural film was obtained in the same manner as in Example 1 except that 5 parts by weight of mica A was supplied to the second and third extruders instead of 2 parts by weight.

(Comparative Example 1)
In the first extruder, instead of linear low density polyethylene A, linear low density polyethylene D (trade name “Atein 4201G” manufactured by Dow Chemical Company, density: 0.912 g / cm ³ , melt flow rate: 1 0.0 g / 10 min), an agricultural film was obtained in the same manner as in Example 1.

(Comparative Example 2)
In the first extruder, instead of linear low density polyethylene A, linear low density polyethylene E (trade name “Daulex 2740E” manufactured by Dow Chemical Co., Ltd., density: 0.940 g / cm ³ , melt flow rate: Agricultural film was obtained in the same manner as in Example 1 except that 1.0 g / 10 min) was supplied.

(Comparative Example 3)
In the first extruder, instead of linear low density polyethylene A, ethylene-vinyl acetate copolymer A (trade name “Novatech LV241” manufactured by Nippon Polyethylene Co., Ltd., density: 0.929 g / cm ³ , melt flow rate: Agricultural film was obtained in the same manner as in Example 1 except that 1.5 g / 10 minutes, content of vinyl acetate component: 8% by weight) was supplied.

(Comparative Example 4)
In the first extruder, instead of the linear low density polyethylene A, a low density polyethylene resin A (trade name “Suntech F2206” manufactured by Asahi Kasei Chemicals Corporation, density: 0.922 g / cm ³ , melt flow rate: 0.6 g Agricultural film was obtained in the same manner as in Example 1 except that / 10 minutes) was supplied.

(Comparative Example 5)
In the second extruder and the third extruder, instead of ethylene-vinyl acetate copolymer A, ethylene-vinyl acetate copolymer D (trade name “Novatech LV110” manufactured by Nippon Polyethylene Co., Ltd., density: 0.922 g / cm ³ , melt flow rate: 0.5 g / 10 min, vinyl acetate content: 2 wt%) was used in the same manner as in Example 1 to obtain an agricultural film.

(Comparative Example 6)
In the second extruder and the third extruder, instead of ethylene-vinyl acetate copolymer A, ethylene-vinyl acetate copolymer E (trade name “Ultrasen 627” manufactured by Tosoh Corporation), density: 0.940 g / cm ³ , melt flow rate: 1.0 g / 10 min, content of vinyl acetate component: 20% by weight) was used in the same manner as in Example 1 to obtain an agricultural film.

(Comparative Example 7)
In the second and third extruders, instead of ethylene-vinyl acetate copolymer A, linear low density polyethylene A (trade name “Daulex 2045G” manufactured by Dow Chemical Co., density: 0.920 g / cm) ³ , melt flow rate: 1.0 g / 10 min) was used in the same manner as in Example 1 to obtain an agricultural film.

(Comparative Example 8)
In the second and third extruders, instead of the ethylene-vinyl acetate copolymer A, a low-density polyethylene resin A (trade name “Suntech F2206” manufactured by Asahi Kasei Chemicals Corporation, density: 0.922 g / cm ³ , melt An agricultural film was obtained in the same manner as in Example 1 except that the flow rate was 0.6 g / 10 min.

(Comparative Example 9)
The same procedure as in Example 1 was conducted except that hindered amine compound B (trade name “CHIMASSORB 944”, number average molecular weight: 2000 to 3100, manufactured by Ciba Japan) was supplied to the first to third extruders instead of hindered amine compound A. A film for agriculture was obtained. The hindered amine compound B did not have a piperidine ring structure represented by Formula 1.

(Comparative Example 10)
The same procedure as in Example 1 was conducted except that mica D (trade name “APR” manufactured by Chuetsu Graphite Industry Co., Ltd., average particle size: 3 μm) was supplied to the second extruder and the third extruder instead of mica A. A film for agriculture was obtained.

(Comparative Example 11)
Example 1 except that mica E (trade name “G-3” manufactured by Chuetsu Graphite Industries Co., Ltd., average particle size: 75 μm) was supplied to the second extruder and the third extruder instead of mica A. An agricultural film was obtained in the same manner.

(Comparative Example 12)
An agricultural film was obtained in the same manner as in Example 1 except that 0.05 parts by weight of mica A was supplied to the second extruder and the third extruder instead of 2 parts by weight.

(Comparative Example 13)
An agricultural film was obtained in the same manner as in Example 1 except that 8 parts by weight of mica A was supplied to the second and third extruders instead of 2 parts by weight.

  The forming stability, tear strength, breaking strength, blocking property, pesticide resistance, total light transmittance and scattered light transmittance of the obtained agricultural film were measured in the following manner, and the results are shown in Tables 1 and 2. Indicated.

(Molding stability)
The forming stability of agricultural films was evaluated according to the following criteria.
○: The agricultural film had a uniform thickness.
(Triangle | delta): The film for agriculture was a little uneven in the thickness.
X: The film for agriculture was uneven in thickness and inferior in appearance.

(Tear strength)
The tear strength in the extrusion direction of the agricultural film was measured in accordance with JIS K7128-2 using an Elmendorf tear tester (manufactured by Toyo Seiki Seisakusho), and judged based on the following criteria.
○: Tear strength was 6N or more.
Δ: Tear strength was 2N or more and less than 6N.
X: The tear strength was less than 2N.

(Strength at break)
The breaking strength of the agricultural film was measured according to JIS K7128 using a strograph (manufactured by Toyo Seiki Seisakusho), and judged based on the following criteria.
A: The strength at break was 2000 g or more.
X: The strength at break was less than 2000 g.

(Blocking property)
Ten planar square test pieces each having a side of 10 cm were cut out from the agricultural film, and a laminated sheet formed by laminating 10 test pieces was left in an oven at 60 ° C. for 6 hours. After 6 hours, the laminated sheet was taken out from the oven, and the state of the laminated sheet was judged based on the following criteria.
○: There was no fusion between the test pieces, and all of them were easily peeled. Δ: Some test pieces were fused together.
X: Most test pieces were fused together.

(Pesticide resistance)
A plane square test piece having a side of 15 cm is cut out from an agricultural film, and the test piece is immersed in a 1N aqueous solution of sulfurous acid for 7 days. After that, an ultraviolet lamp is used to apply 50 W / m ² to the test piece. Were irradiated for 48 hours. The residual elongation at break of the test piece after UV irradiation was measured according to JIS K7128 and judged based on the following criteria.
A: The elongation at break was 400% or more.
X: The residual elongation at break was less than 400%.

(Total light transmittance)
The total light transmittance of the agricultural film was measured using a haze meter (trade name “NDH2000” manufactured by Nippon Denshoku Industries Co., Ltd.) and judged based on the following criteria.
A: The total light transmittance was 80% or more.
Δ: Total light transmittance was 60% or more and less than 80%.
X: The total light transmittance was less than 60%.

(Scattered light transmittance)
The scattered light transmittance of the agricultural film was measured using a haze meter (trade name “NDH2000” manufactured by Nippon Denshoku Industries Co., Ltd.) and judged based on the following criteria.
A: The scattered light transmittance was 30% or more and less than 60%.
Δ: The scattered light transmittance was 60% or more, or 20% or more and less than 30%.
X: Scattered light transmittance was less than 20%.

Claims (1)

A linear low density polyethylene having a density of 0.915 to 0.930 g / cm ³ and a melt flow rate of 0.5 to 4.0 g / 10 min, and a piperidine ring structure represented by formula 1 in the molecule And an intermediate layer containing a hindered amine compound having a number average molecular weight of 1000 or more and a thickness of 20 μm or more and laminated on both sides of the intermediate layer, and the vinyl acetate component content is 5 to 5%. And an outer layer containing an ethylene-vinyl acetate copolymer having a melt flow rate of 0.5 to 4.0 g / 10 min and a thickness of 15 to 5%, and an overall thickness of 30 to 150 μm In addition, the thickness of the intermediate layer is 50 to 90% of the total thickness, and at least one of the intermediate layer and the outer layer contains mica having an average particle diameter of 5 to 40 μm, and the total amount of the mica Is 0.1 to 5 parts by weight with respect to 100 parts by weight of the total amount of synthetic resin. In Formula 1, R ₁ represents a functional group or compound (including oligomers and polymers) having 1 or more carbon atoms and containing at least one methylene group.