JP2008113635A - Agricultural film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an agricultural film excellent in tearing strength and impact strength, and hardly causing a break caused by a strong wind or flying objects. <P>SOLUTION: This agricultural film is obtained by unitedly laminating an outer layer (A), a middle layer (B) and an inner layer (C) in this order. The outer layer (A) and the inner layer (C) are made from a resin composition which contains ≥80 wt.% of prescribed linear low density polyethylene. The middle layer (B) is made from a resin composition which is composed of 30-90 wt.% of prescribed linear low density polyethylene and 10-70 wt.% of a prescribed ethylene-vinyl acetate copolymer, and contains ≤15 wt.% of vinyl acetate. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an agricultural film used in a crop cultivation facility.

  Conventionally, as a means for cultivating agricultural crops, house cultivation using an agricultural house has been actively performed. In the above-mentioned house cultivation, the farm house can make the inside of the house suitable for the growth of the crop, protect the crop from the wind and rain, and prevent the crop from being damaged by flying objects such as stones and dust.

  The agricultural house is formed by spreading and covering an agricultural film on the framework of the house. Conventionally, a polyvinyl chloride film has been frequently used as the agricultural film used here. However, in recent years, agricultural films mainly composed of ethylene-vinyl acetate copolymer have been actively used in consideration of environmental safety.

  As an agricultural film mainly composed of such an ethylene-vinyl acetate copolymer, for example, in Patent Document 1, the outer layer of the film is mainly a resin composition comprising an ethylene-α-olefin copolymer and high-density polyethylene. The film intermediate layer is composed mainly of a resin composition containing an ethylene-vinyl acetate copolymer and inorganic fine particles containing at least one atom of Mg, Ca, Al, Si, Li, and the film inner layer is A three-layer agricultural film mainly composed of an ethylene-vinyl acetate copolymer is disclosed.

  Patent Document 2 discloses a three-layer laminated film in which the inner and outer layers of the film are layers made of an ethylene-vinyl acetate copolymer, and the film intermediate layer is obtained by copolymerization with a metallocene catalyst. It is a layer mainly composed of a resin composition containing an olefin copolymer, an ethylene-vinyl acetate copolymer, and inorganic fine particles containing at least one atom of Mg, Ca, Al, Si, and Li. An agricultural film characterized by the above is disclosed.

  Further, in Patent Document 3, the first layer is a layer mainly composed of an ethylene-α-olefin copolymer, and the second layer is an ethylene-α-olefin based on 100 parts by weight of the ethylene-vinyl acetate copolymer. It is a layer made of a resin composition containing 25 to 100 parts by weight of a copolymer, and the third layer is an ethylene-α-olefin copolymer of 0 to 50 with respect to 100 parts by weight of an ethylene-vinyl acetate copolymer. An agricultural film characterized by being a layer made of a resin composition containing parts by weight is disclosed.

  However, the agricultural film mainly composed of an ethylene-vinyl acetate copolymer as described in Patent Documents 1 to 3 is inferior in tear strength and impact strength. Therefore, when a strong wind is blown by a typhoon or the like, the agricultural film is used. The film could not be used for a long period of time because it was torn from the crease part of the film, or the film was broken by flying objects such as stones and dust.

JP 2000-324957 A JP 2000-238201 A JP 2001-334612 A

  The present invention provides an agricultural film that is excellent in tear strength and impact strength and is less susceptible to tearing due to strong winds and flying objects.

The agricultural film of the present invention is an agricultural film in which an outer layer (A), an intermediate layer (B), and an inner layer (C) are laminated and integrated in this order, and the outer layer (A) and the inner layer (C) are A resin composition comprising 80% by weight or more of linear low density polyethylene having a density of 0.890 to 0.920 g / cm ³ and a melt mass flow rate of 0.3 to 5.0 g / 10 min. The intermediate layer (B) has a density of 0.890 to 0.920 g / cm ³ and a linear low density polyethylene having a melt mass flow rate of 0.3 to 5.0 g / 10 min. And an ethylene-vinyl acetate copolymer having a vinyl acetate component content of 5 to 25% by weight and a melt mass flow rate of 0.5 to 4.0 g / 10 minutes, and vinyl acetate. Component content is 15 layers It is characterized by comprising a resin composition having an amount of not more than%.

  As the resin component constituting the outer layer (A) and the inner layer (C) of the agricultural film of the present invention, a resin composition containing linear low density polyethylene is used.

  The linear low-density polyethylene is obtained by copolymerizing ethylene and α-olefin at medium and low pressure using a single-site catalyst such as a Ziegler catalyst or a metallocene catalyst. By adjusting the amount, the density range can be controlled. Examples of the α-olefin include propylene, 1-butene, 1-pentene, 1-hexene, 1-octene, 4-methyl-1-pentene and the like.

If the density of the linear low-density polyethylene is low, the surface of the agricultural film becomes sticky and becomes easy to block, making it difficult to develop the agricultural film, or tearing strength of the agricultural film. On the other hand, if it is high, the impact strength of the agricultural film is reduced, and the film is easily broken due to flying objects, so it is limited to 0.890 to 0.920 g / cm ³ , and is 0.900 to preferably ^{0.915g / cm 3, 0.906~0.915g / cm} 3 is more preferable.

  The density of the thermoplastic resin such as linear low density polyethylene or ethylene-vinyl acetate copolymer in the present invention was measured in accordance with JIS K 7112 “Method for measuring density of plastic-non-foamed plastic”. It means density.

  In addition, when the melt mass flow rate of the linear low density polyethylene (hereinafter abbreviated as “MFR”) is low, the film-forming stability of the agricultural film is lowered, whereas when it is high, the tear strength of the agricultural film and Since impact strength becomes insufficient, it is limited to 0.3 to 5.0 g / 10 minutes, and 0.8 to 3.0 g / 10 minutes is preferable.

  The MFR of thermoplastic resins such as linear low-density polyethylene and ethylene-vinyl acetate copolymer in the present invention conforms to JIS K 7210 “Plastics—Testing Method for Melt Mass Flow Rate (MFR) of Thermoplastic Plastics”. The value measured under the conditions of a temperature of 190 ° C. and a load of 21.18N.

  And, since the content of the linear low density polyethylene in the resin composition constituting the outer layer (A) and the inner layer (C) is small, the tear strength and impact strength of the agricultural film become insufficient. It is limited to 80% by weight or more, and preferably 85% by weight or more.

  The resin composition constituting the outer layer (A) and the inner layer (C) contains a thermoplastic resin other than the above-described linear low density polyethylene as long as the effects of the present invention are not impaired. However, it is preferable to consist only of the above-mentioned linear low density polyethylene. Moreover, the resin composition which comprises the outer layer (A) of an agricultural film and the resin composition which comprises an inner layer (C) may not be the same composition, However, It is preferable that it is the same composition.

  And as a resin component which comprises the intermediate | middle layer (B) of the agricultural film of this invention, the resin composition formed by containing a linear low density polyethylene and an ethylene-vinyl acetate copolymer is used.

As the linear low density polyethylene contained in the resin composition constituting the intermediate layer (B), the linear low density used in the resin composition constituting the outer layer (A) and the inner layer (C) described above. For the same reason as in the case of polyethylene, linear low density polyethylene having a density of 0.890 to 0.920 g / cm ³ and an MFR of 0.3 to 5.0 g / 10 min is used.

  In addition, when the content of the vinyl acetate component in the ethylene-vinyl acetate copolymer is small, the impact strength and flexibility of the agricultural film are reduced, whereas when the content is large, the tear strength of the agricultural film is reduced. It is limited to 5 to 25% by weight, preferably 10 to 20% by weight, and more preferably 10 to 15% by weight.

  And, when the MFR of the ethylene-vinyl acetate copolymer is low, the film-forming stability of the agricultural film is lowered. On the other hand, when the MFR is high, the tear strength and impact strength of the agricultural film are insufficient. It is limited to 0.5 to 4.0 g / 10 minutes, and 0.8 to 2.0 g / 10 minutes is preferable.

  In addition, if the content of the linear low-density polyethylene in the resin composition constituting the intermediate layer (B) is small, the tear strength and impact strength of the agricultural film are lowered, while if large, the content of the agricultural film is Since flexibility and film-forming stability are lowered, the content is limited to 30 to 90% by weight, and preferably 60 to 80% by weight.

  And if content of the ethylene-vinyl acetate copolymer in the resin composition which comprises the said intermediate | middle layer (B) is small, while the softness | flexibility and film-forming stability of an agricultural film will fall, when many, agriculture Since the tear strength and impact strength of the film for use are lowered, it is limited to 10 to 70% by weight, and preferably 20 to 40% by weight.

  In addition, if the resin composition which comprises the said intermediate | middle layer (B) is in the range which does not impair the effect of this invention, thermoplastic resins other than the above-mentioned linear low density polyethylene and ethylene-vinyl acetate copolymer are used. However, it is preferable to consist only of the above-mentioned linear low density polyethylene and ethylene-vinyl acetate copolymer.

  Furthermore, if the content of the vinyl acetate component in the resin composition constituting the intermediate layer (B) is large, the tear strength and impact strength of the agricultural film become insufficient, so it is limited to 15% by weight or less, 10 weight% or less is preferable. However, if the content of the vinyl acetate component in the resin composition constituting the intermediate layer (B) is too small, the flexibility of the agricultural film may be lowered, so that it is 0.5% by weight or more. Is preferred.

  In addition, when the resin composition which comprises the said intermediate | middle layer (B) contains thermoplastic resins other than the above-mentioned linear low density polyethylene and ethylene-vinyl acetate copolymer, the said intermediate | middle layer (B) The content of the vinyl acetate component in the constituent resin composition is the content of the vinyl acetate component relative to the total weight of the resin composition including the above-mentioned linear low density polyethylene and thermoplastic resin other than the ethylene-vinyl acetate copolymer. Amount.

  The surface of the inner layer (C) of the present invention is preferably provided with an antifogging droplet layer formed of an antifogging droplet agent. Thus, by providing an anti-fogging droplet layer on the surface of the inner layer (C) of the agricultural film, when the agricultural film is used in an agricultural house, water droplets generated due to a temperature difference inside and outside the house are transferred to the house. Since it flows through the anti-fogging drip layer without falling directly on the crops cultivated inside, it is possible to prevent diseases from occurring in the crops.

  As the anti-fogging liquid drop agent, an aqueous medium containing colloidal silica and / or colloidal alumina is used, and in particular, anti-fogging formed by dispersing colloidal silica and / or colloidal alumina in an aqueous medium. A drop agent is preferred.

  The aqueous medium used for the anti-fogging drop agent is not particularly limited, and may be water alone or a mixed solution of water and a water-soluble medium such as alcohol. In addition, when using the liquid mixture of a water-soluble medium and water as an aqueous medium, when there is much content of the water-soluble medium in an aqueous medium, there exists a possibility that it may ignite when drying an anti-fog drop. Therefore, 50% by weight or less is preferable.

  The shape of the colloidal silica is not particularly limited, but a particulate shape or a continuous particle shape is preferably used.

  Moreover, the shape of the colloidal alumina used for the said anti-fogging dripping agent is not specifically limited, For example, particle shape, plate shape, needle shape, feather shape etc. are mentioned. The shape of the colloidal alumina is preferably selected as appropriate in accordance with characteristics such as initial antifogging property, antifogging sustainability, and transparency required for agricultural films.

  In addition, additives such as a hydrophilic resin binder, a hydrophobic resin binder, a viscosity modifier, an emulsion, and an antifoaming agent may be added to the antifogging drop agent as necessary.

  In addition, the method for producing the antifogging drop is not particularly limited, and may be a conventionally known method. For example, the aqueous medium and colloidal silica and / or colloidal alumina are mixed and further required. Depending on the case, an additive may be added and the mixture may be produced by stirring with a stirring device such as a homogenizer.

  And it does not specifically limit as a method of forming an anti-fogging droplet layer in the surface of the inner layer (C) of the agricultural film of this invention, For example, roll coating methods, such as the said anti-fogging droplet agent, a gravure coater And a method of applying the coating to the surface of the inner layer (C) of the agricultural film by a barcode method, a dip coating method, a spray method, a brush coating method, or the like, followed by drying.

  In addition, in the said agricultural film, if it is in the range which does not impair the effect of this invention, an inorganic heat retention agent, an organic heat retention agent, a light stabilizer, antioxidant, a ultraviolet absorber, an antifog agent, a lubricant, a pigment, etc. These additives may be added.

  The inorganic heat-retaining agent is added for the purpose of improving the heat retention of agricultural films and preventing extrusion fluctuations during film formation of agricultural films. Such an inorganic heat insulating agent is not particularly limited. For example, magnesium oxide, calcium oxide, aluminum oxide, magnesium carbonate, calcium carbonate, magnesium sulfate, calcium sulfate, aluminum sulfate, lithium phosphate, calcium phosphate, magnesium silicate, silicic acid. Calcium, aluminum silicate, kaolin, clay, talc, hydrotalcite, lithium aluminum composite hydroxide, alkali metal, alkaline earth metal, transition metal, group 12 (group 2B) element, group 14 other than carbon ( 4B)) or a composite hydroxide having at least two elements selected from elements. These may be used alone or in combination of two or more.

  As the light stabilizer, conventionally known light stabilizers can be used. Among these, hindered amine light stabilizers are preferable. Examples of the hindered amine light stabilizer include 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] } Etc., and 2 or more types may be used together.

  And as said antioxidant, although a conventionally well-known thing can be used, 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, and these may be used alone or in combination of two or more. .

  As the ultraviolet absorber, conventionally known ones can be used, for example, 2,4-dihydroxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 2-hydroxy-4-dodecyloxybenzophenone, 2,2 ′. -Benzophenone ultraviolet absorbers such as dihydroxy-4-methoxybenzophenone, 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 ′) Benzotriazole ultraviolet rays such as 5′-di-tert-butylphenyl) -5-chlorobenzotriazole and 2- (2′-hydroxy-3 ′, 5′-di-tert-amylphenyl) -5-chlorobenzotriazole Absorbers, salicylic acid ester ultraviolet absorbers, cyanoacrylate ultraviolet absorbers and the like may be mentioned, and these may be used alone or in combination of two or more.

  And as said fog prevention agent, a conventionally well-known thing can be used, For example, surfactants, such as silicone type and a fluorine type, are mentioned. As the lubricant, conventionally known ones can be used, 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. .

  Furthermore, if the thickness of the agricultural film of the present invention is thin, the tear strength and impact strength of the agricultural film may decrease, while if it is thick, cutting, joining, and stretching work of the agricultural film become difficult. Since handling property may fall, 50-200 micrometers is preferable and 70-170 micrometers is more preferable.

  Next, a method for forming the agricultural film will be described. The method for forming the agricultural film is not particularly limited. For example, a film forming apparatus in which three extruders are connected to one circular die via a connector is prepared. The resin compositions for the outer layer (A), the intermediate layer (B), and the inner layer (C) are supplied to the three extruders, melted and kneaded in each extruder, and then the molten resin composition is circular. Supply to the die and co-extrusion into a cylindrical shape from the circular die, and supply compressed air from the center of the circular die to stretch the co-extruded resin composition in the circumferential direction to make a long cylinder The method of forming a cylindrical film, opening this cylindrical film, and winding up is mentioned.

  The agricultural film of the present invention is an agricultural film in which an outer layer (A), an intermediate layer (B), and an inner layer (C) are laminated and integrated in this order, and the outer layer (A) and the inner layer (C) are And a resin composition comprising 80% by weight or more of a predetermined linear low density polyethylene, and the intermediate layer (B) comprises 30 to 90% by weight of a predetermined linear low density polyethylene and predetermined ethylene. -It is excellent in tear strength and impact strength because it comprises a vinyl acetate copolymer of 10 to 70% by weight and a resin composition having a vinyl acetate component content of 15% by weight or less. Therefore, the agricultural film of the present invention is preferably used for a long period of time because the crease part of the film is not torn by a strong wind or the like, and the film is hardly broken by flying objects such as stones and dust. can do.

  Furthermore, by providing an anti-fogging drop layer on the surface of the inner layer (C) of the agricultural film of the present invention, when the agricultural film is used in an agricultural house, water droplets generated due to temperature differences inside and outside the house are generated. Since it flows through the anti-fogging droplet layer without falling directly on the crop cultivated in the house, it is possible to prevent the disease from occurring in the crop.

  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)
A film forming apparatus in which three extruders are connected to one circular die via a connector is prepared, and the first extruder of this film forming apparatus is used as an extruder for the outer layer (A). Low-density polyethylene a (trade name “Atein 4201” manufactured by Dow Chemical Co., Ltd., density: 0.912 g / cm ³ , MFR: 1.0 g / 10 min) is supplied in an amount of 100 parts by weight. ), 60 parts by weight of linear low density polyethylene a and ethylene-vinyl acetate copolymer a (trade name “H-1011” manufactured by Sumitomo Chemical Co., Ltd., vinyl acetate component content: 15% by weight, density: 0.938 g / cm ³ , MFR: 1.0 g / 10 min) 40 parts by weight of a resin composition (vinyl acetate component content: 6% by weight) is supplied, and the third extruder is used for the inner layer (C). As an extruder, linear low density polyethylene a100 After supplying the quantity part and melt-kneading in each extruder, the molten resin composition is supplied to the circular die from the first to third extruders, and the outer layer (A), the intermediate layer (B), the inner layer (C) is co-extruded into a cylindrical shape from a circular die so that it is laminated and integrated in this order, and compressed air is supplied from the center of the circular die to surround the co-extruded resin composition. A long cylindrical film is formed by stretching in the direction, and the cylindrical film is cut open and wound, so that the thickness ratio of the outer layer (A), the intermediate layer (B), and the inner layer (C) is 1 An agricultural film having a thickness of / 4/1 and a total thickness of 150 μm was obtained.

(Example 2)
Linear low density polyethylene to be supplied to the first extruder and the third extruder is linear low density polyethylene b (trade name “Evolue SP0510” manufactured by Prime Polymer Co., Ltd., density: 0.905 g / cm ³ , MFR: 1.0 g / 10 min), and the resin composition supplied to the second extruder is a resin composition (vinyl acetate component) comprising 60 parts by weight of linear low density polyethylene b and 40 parts by weight of ethylene-vinyl acetate copolymer An agricultural film was obtained in the same manner as in Example 1 except that the content was 6% by weight.

(Example 3)
Linear low density polyethylene to be supplied to the first extruder and the third extruder is linear low density polyethylene c (trade name “Elite 5400G” manufactured by Dow Chemical Company, density: 0.916 g / cm ³ , MFR: 1.0 g / 10 min), and the resin composition supplied to the second extruder is a resin composition comprising 60 parts by weight of linear low-density polyethylene c and 40 parts by weight of ethylene-vinyl acetate copolymer (vinyl acetate component) An agricultural film was obtained in the same manner as in Example 1 except that the content was 6% by weight.

Example 4
The linear low density polyethylene supplied to the first extruder and the third extruder is linear low density polyethylene d (trade name “Excellen FX CX1001” manufactured by Sumitomo Chemical Co., Ltd., density: 0.898 g / cm ³ , MFR. : 1.0 g / 10 min), and the resin composition supplied to the second extruder is a resin composition (vinyl acetate) comprising 60 parts by weight of linear low density polyethylene d and 40 parts by weight of ethylene-vinyl acetate copolymer a. An agricultural film was obtained in the same manner as in Example 1 except that the component content was 6% by weight.

(Example 5)
Instead of 100 parts by weight of linear low density polyethylene a in the first extruder and the third extruder, 82 parts by weight of linear low density polyethylene a and low density polyethylene a (trade name “Suntech M2204” manufactured by Asahi Kasei Chemicals Corporation), An agricultural film was obtained in the same manner as in Example 1 except that a resin composition comprising 18 parts by weight (density: 0.922 g / cm ³ , MFR: 0.4 g / 10 min) was supplied.

(Example 6)
The resin composition supplied to the second extruder was prepared by adding 60 parts by weight of linear low density polyethylene a and ethylene-vinyl acetate copolymer b (trade name “Ultrasen 513” manufactured by Tosoh Corporation, content of vinyl acetate component: 5% by weight. %, Density: 0.928 g / cm ³ , MFR: 1.0 g / 10 min) The same as in Example 1 except that the resin composition was 40 parts by weight (vinyl acetate component content: 2% by weight). An agricultural film was obtained.

(Example 7)
The resin composition supplied to the second extruder was obtained by adding 60 parts by weight of linear low-density polyethylene a and ethylene-vinyl acetate copolymer c (trade name “Ultrasen 627” manufactured by Tosoh Corporation, vinyl acetate component content: 20 wt. %, Density: 0.940 g / cm ³ , MFR: 1.0 g / 10 min) The same as in Example 1 except that the resin composition was 40 parts by weight (vinyl acetate component content: 8% by weight). An agricultural film was obtained.

(Example 8)
The resin composition supplied to the second extruder is a resin composition comprising 90 parts by weight of linear low density polyethylene a and 10 parts by weight of ethylene-vinyl acetate copolymer (vinyl acetate component content: 1.5% by weight). An agricultural film was obtained in the same manner as in Example 1 except that.

Example 9
The resin composition supplied to the second extruder is a resin composition comprising 30 parts by weight of linear low density polyethylene a and 70 parts by weight of ethylene-vinyl acetate copolymer (vinyl acetate component content: 10.5% by weight). An agricultural film was obtained in the same manner as in Example 1 except that.

(Comparative Example 1)
The linear low density polyethylene supplied to the first extruder and the third extruder is linear low density polyethylene e (trade name “Affinity VP8770G” manufactured by Dow Chemical Co., Ltd., density: 0.885 g / cm ³ , MFR: 1.0 g / 10 min), and the resin composition supplied to the second extruder is a resin composition comprising 60 parts by weight of linear low density polyethylene e and 40 parts by weight of ethylene-vinyl acetate copolymer (vinyl acetate component). An agricultural film was obtained in the same manner as in Example 1 except that the content was 6% by weight.

(Comparative Example 2)
The linear low density polyethylene supplied to the first extruder and the third extruder is linear low density polyethylene f (trade name “Evolue SP2510” manufactured by Prime Polymer Co., Ltd., density: 0.922 g / cm ³ , MFR: 1.0 g / 10 min), and the resin composition supplied to the second extruder is a resin composition (vinyl acetate component comprising 60 parts by weight of linear low density polyethylene f and 40 parts by weight of ethylene-vinyl acetate copolymer). An agricultural film was obtained in the same manner as in Example 1 except that the content was 6% by weight.

(Comparative Example 3)
The linear low density polyethylene supplied to the first extruder and the third extruder is linear low density polyethylene g (trade name “Daulex 2035” manufactured by Dow Chemical Co., Ltd., density: 0.919 g / cm ³ , MFR). : 6.0 g / 10 min), and the resin composition supplied to the second extruder was a resin composition (vinyl acetate) comprising 60 parts by weight of linear low density polyethylene g and 40 parts by weight of ethylene-vinyl acetate copolymer a. An agricultural film was obtained in the same manner as in Example 1 except that the component content was 6% by weight.

(Comparative Example 4)
Other than supplying the resin composition consisting of 60 parts by weight of linear low density polyethylene a and 40 parts by weight of low density polyethylene instead of 100 parts by weight of linear low density polyethylene a to the first extruder and the third extruder Produced an agricultural film in the same manner as in Example 1.

(Comparative Example 5)
The resin composition supplied to the second extruder is a resin composition comprising 95 parts by weight of linear low density polyethylene a and 5 parts by weight of ethylene-vinyl acetate copolymer (vinyl acetate component content: 0.75% by weight). An agricultural film was obtained in the same manner as in Example 1 except that.

(Comparative Example 6)
The resin composition to be supplied to the second extruder was a resin composition comprising 20 parts by weight of linear low density polyethylene a and 80 parts by weight of ethylene-vinyl acetate copolymer (vinyl acetate component content: 12% by weight). Except for this, an agricultural film was obtained in the same manner as in Example 1.

(Comparative Example 7)
A film forming apparatus is prepared in which one extruder is connected to one circular die via a connector, and 90 parts by weight of linear low density polyethylene a and ethylene-vinyl acetate are added to the extruder of this film forming apparatus. A resin composition comprising 10 parts by weight of polymer a (vinyl acetate component content: 1.5% by weight) was supplied, melted and kneaded, and then the molten resin composition was supplied from an extruder to a circular die. Extruded into a cylindrical shape from the die, compressed air is supplied from the center of the circular die, and the extruded resin composition is stretched in the circumferential direction to form a long cylindrical film. An agricultural film having a thickness of 150 μm was obtained by cutting and winding the film.

(Manufacture of anti-fogging drops)
100 parts by weight of water, 5 parts by weight of colloidal silica (trade name “ST-PSM” manufactured by Nissan Chemical Industries, Ltd.), 1 part by weight of colloidal alumina (trade name “Alumina Sol 100” manufactured by Nissan Chemical Industries, Ltd.) and polyethylene oxide (Sumitomo Seiki) 2 parts by weight) were added and mixed to obtain an antifogging drop agent in which colloidal silica and colloidal alumina were dispersed in water containing polyethylene oxide.

(Formation of anti-fogging droplet layer)
The anti-fogging droplets obtained as described above were used for agricultural purposes obtained in Examples 1 to 9 and Comparative Examples 1 to 6 and the surface of the agricultural film inner layer (C) and Comparative Example 7 On one surface of the film, it was coated with a gravure coater so that the coating amount before drying was 10 g / m ² , and dried with hot air to form an antifogging droplet layer.

  Next, the following evaluation test was implemented about the agricultural film in which the anti-fogging droplet layer obtained by the above was formed, and the result was shown in Table 1. In Table 1, “LLDPE” means linear low density polyethylene, “LDPE” means low density polyethylene, and “EVA” means ethylene-vinyl acetate copolymer.

(Film formation stability)
The obtained agricultural film was visually observed, and film forming stability was evaluated according to the following criteria.
A: An agricultural film having a uniform thickness and excellent appearance.
Δ: Agricultural film having a slightly non-uniform thickness.
X: An agricultural film having a non-uniform thickness and poor appearance.

(Blocking property)
Two pieces of the agricultural film obtained were prepared, overlapped so that the outer layers (A) of these agricultural films face each other, a weight of 5 kg was placed on the overlapped film, It was left in a constant temperature room for 48 hours. And the film piled up from the temperature-controlled room was taken out, two films were peeled, and blocking property was evaluated on the following reference | standard. In addition, about the agricultural film obtained in the comparative example 7, it is as above except having overlap | superposed so that the surface where the anti-fog drip layer of two agricultural films was not provided might be in the state which opposes. The blocking property was evaluated in the same manner.
○: The two films were not blocked and could be easily peeled off.
Δ: The two films were slightly blocked and were somewhat difficult to remove.
X: The two films were blocked and difficult to peel off.

(Tear strength)
The tear strength (N) of the obtained agricultural film was measured according to JIS K 7128 using an Elmendorf tear strength measuring machine (manufactured by Toyo Seiki Seisakusho), and the tear strength was evaluated according to the following criteria.
○: Tear strength was 15 N or more.
Δ: Tear strength was 10N or more and less than 15N.
X: The tear strength was less than 10N.

(Impact strength)
The impact strength (J) of the obtained agricultural film was measured according to ASTM D 3420 using a film impact tester (manufactured by Tester Sangyo Co., Ltd.), and the impact strength was evaluated according to the following criteria.
○: Impact strength was 2.5 J or more.
Δ: Impact strength was 1.5 J or more and less than 2.5 J.
X: The impact strength was less than 1.5 J.

Claims (2)

An agricultural film in which an outer layer (A), an intermediate layer (B), and an inner layer (C) are laminated and integrated in this order, and the outer layer (A) and the inner layer (C) have a density of 0.890 to 0.00. The intermediate layer (B) comprises a resin composition comprising 920 g / cm ³ and a linear low density polyethylene having a melt mass flow rate of 0.3 to 5.0 g / 10 min and containing 80% by weight or more. Has a density of 0.890 to 0.920 g / cm ³ and a melt mass flow rate of 0.3 to 5.0 g / 10 min, a linear low density polyethylene of 30 to 90% by weight, and a vinyl acetate component content. 5 to 25% by weight, a melt mass flow rate of 0.5 to 4.0 g / 10 minutes, and an ethylene-vinyl acetate copolymer of 10 to 70% by weight and a vinyl acetate component content of 15% by weight The following resin composition Agricultural film characterized by The antifogging droplet layer formed from an antifogging droplet agent comprising colloidal silica and / or colloidal alumina in an aqueous medium is provided on the surface of the inner layer (C). The agricultural film as described in 1.