JP5459819B2 - Agricultural film - Google Patents

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 be adjusted to conditions suitable for the growth of the crop, protect the crop from the wind and rain, and prevent damage to the crop 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 mechanical strength and transparency and hardly breaks 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 , density 0.890~0.920g / cm ^3, melt mass flow Rei door 0. With a copolymer in which linear low density polyethylene containing 80% or more by weight resin composition of the Ah Ri and ethylene and 1-octene in 3~5.0g / 10 min, the intermediate layer (B) Is an ethylene-vinyl acetate copolymer having a vinyl acetate component content of 18-30% by weight and a melt mass flow rate of 0.5-4.0 g / 10 min, and Mg, Al, Ca, Zn, Si. And a resin composition containing 3 to 20% by weight of inorganic particles containing at least one atom selected from the group consisting of Li.

  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, a metallocene catalyst, or a chromium catalyst. The density range can be controlled by adjusting the type and amount of olefin. The catalyst is preferably a metallocene catalyst. As the α- olefin, since agricultural film is excellent in transparency and strength, 1-octene is used.

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 0.915 g / cm ³ is preferred.

  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 mechanical strength such as impact strength becomes insufficient, it is limited to 0.3 to 5.0 g / 10 minutes, and preferably 0.8 to 3.0 g / 10 minutes.

  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.

  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 an ethylene-vinyl acetate copolymer and a predetermined | prescribed inorganic particle is used.

  If 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 lowered, while if it is large, the agricultural film is too soft and the workability is lowered. Or, since the film-forming stability of the agricultural film is lowered, it is limited to 18 to 30% by weight, and preferably 18 to 25% 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.

  When the content of the ethylene-vinyl acetate copolymer in the resin composition constituting the intermediate layer (B) is small, the flexibility and film-forming stability of the agricultural film are lowered. 50 to 85% by weight is preferable, and 60 to 75% by weight is more preferable.

  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, you may contain thermoplastic resins other than the above-mentioned ethylene-vinyl acetate copolymer. However, it preferably comprises only the above-mentioned ethylene-vinyl acetate copolymer.

  The intermediate layer (B) contains inorganic particles containing at least one atom selected from the group consisting of Mg, Al, Ca, Zn, Si, and Li. In this way, the intermediate layer (B) contains inorganic particles containing at least one or more predetermined atoms, thereby improving the heat retention of the agricultural film and preventing extrusion fluctuations during film formation of the agricultural film. Thus, the film-forming stability of agricultural films is improved.

Examples of such inorganic particles include magnesium oxide, calcium oxide, aluminum oxide, silicon oxide, lithium hydroxide, magnesium hydroxide, calcium hydroxide, aluminum hydroxide, magnesium carbonate, calcium carbonate, calcium sulfate, magnesium sulfate, Aluminum sulfate, lithium phosphate, calcium phosphate, magnesium silicate, calcium silicate, aluminum silicate, calcium aluminate, magnesium aluminate, sodium aluminosilicate, potassium aluminosilicate, calcium aluminosilicate, kaolin, clay, talc, mica, hydrotalcite Compound (including hydrotalcite), aluminum-lithium-magnesium composite carbonate compound, aluminum-lithium-magnesium composite silicate compound, magnesium Aluminum - silicon composite hydroxide, magnesium - aluminum - silicon composite sulfate compounds, magnesium - aluminum - like silicon composite carbonate compound can be mentioned, hydrotalcite is preferred. Here, the hydrotalcite compound is M ²⁺ _1-x M ³⁺ _x (OH) ₂ A ^n- _{x / n} · nH ₂ O [M ²⁺ and M ³⁺ are divalent and trivalent Ion, x = 0.25 to 0.33, and A is a guest compound]. In addition, an inorganic particle may be used independently or 2 or more types may be used together.

  When the content of the inorganic particles in the intermediate layer (B) is small, the heat retaining property of the agricultural film is lowered. On the other hand, when the content is large, the transparency of the agricultural film is lowered. Therefore, the content is limited to 3 to 20% by weight. 5 to 10% by weight is preferred.

  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, and examples thereof include an inflation method, a T-die method, a calendar method, and the like, and a multilayer extrusion method by an inflation method is preferable.

  As the multilayer extrusion method based on the inflation method, for example, a film forming apparatus in which three extruders are connected to one circular die via a connector is prepared, and the three extruders of this film forming apparatus are prepared. The outer layer (A), the intermediate layer (B) and the inner layer (C) are supplied with resin compositions, melted and kneaded in each extruder, and then supplied in a molten state to the circular die. Co-extruded into a cylindrical shape from a circular die and supplied with compressed air from the center of the circular die to stretch the co-extruded resin composition in the circumferential direction to form a long cylindrical film. And a method of cutting and winding the cylindrical film.

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 , density 0.890~0.920g / cm ^3, melt mass flow Rei door 0. With a copolymer in which linear low density polyethylene containing 80% or more by weight resin composition of the Ah Ri and ethylene and 1-octene in 3~5.0g / 10 min, the intermediate layer (B) Is an ethylene-vinyl acetate copolymer having a vinyl acetate component content of 18-30% by weight and a melt mass flow rate of 0.5-4.0 g / 10 min, and Mg, Al, Ca, Zn, Si. And a resin composition containing 3 to 20% by weight of inorganic particles containing at least one kind of atom selected from the group consisting of Li, and excellent in mechanical strength and transparency such as tear strength and impact strength. Yes. 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, since the agricultural film of the present invention contains a predetermined amount of predetermined inorganic particles in the intermediate layer, it has excellent transparency and heat retention.

  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 “Moretech 0138NK” manufactured by Prime Polymer Co., Ltd., polymerization catalyst: Ziegler catalyst, α-olefin: 1-octene, density: 0.916 g / cm ³ , MFR: 1.5 g / 10 min) 100 Part by weight is supplied to the first extruder, and the second extruder is used as the intermediate layer (B) extruder, and ethylene-vinyl acetate copolymer A (trade name “Ultrasen 627” manufactured by Tosoh Corporation, vinyl acetate component) Content: 20% by weight, density: 0.941 g / cm ³ , MFR: 0.8 g / 10 min) 90 parts by weight and inorganic fine particles A as magnesium-aluminum composite hydroxide salt (manufactured by Kyowa Chemical Industry Co., Ltd. D T-4A ") A resin composition comprising 10 parts by weight is supplied to the second extruder, and the third extruder is used as an extruder for the inner layer (C), and 80 parts by weight of linear low density polyethylene A and low density polyethylene are used. 20 parts by weight of A (trade name “Suntech F1920” manufactured by Asahi Kasei Chemicals Corporation, density: 0.921 g / cm ³ , MFR: 2.0 g / 10 min) is supplied to the third extruder and melted in each extruder. After kneading, the molten resin composition is supplied from the first to third extruders to the circular die, and the outer layer (A), the intermediate layer (B), and the inner layer (C) are laminated and integrated in this order. The cylindrical die is coextruded into a cylindrical shape, and compressed air is supplied from the center of the circular die, and the coextruded resin composition is stretched in the circumferential direction to produce a long cylindrical film. Membrane and this cylindrical film By winding paving, outer layer (A), the thickness ratio of the intermediate layer (B) and the inner layer (C) is, and the total thickness was obtained agricultural film of 150μm in 1/4/1.

(Example 2)
Example 1 except that 97 parts by weight of linear low density polyethylene A instead of 90 parts by weight and 3 parts by weight of magnesium-aluminum composite hydroxide salt instead of 10 parts by weight were fed to the second extruder. In the same manner as above, an agricultural film having an outer layer (A), intermediate layer (B), and inner layer (C) thickness ratio of 1/4/1 and a total thickness of 150 μm was obtained.

(Example 3)
Example except that 80 parts by weight of ethylene-vinyl acetate copolymer A instead of 90 parts by weight and 20 parts by weight of magnesium-aluminum composite hydroxide salt instead of 10 parts by weight were fed to the second extruder. In the same manner as in No. 1, an agricultural film having an outer layer (A), intermediate layer (B), and inner layer (C) thickness ratio of 1/4/1 and a total thickness of 150 μm was obtained.

( Comparative Example 7 )
In the same manner as in Example 1, except that 60 parts by weight of linear low density polyethylene A and 40 parts by weight of low density polyethylene A were supplied to the first extruder instead of the linear low density polyethylene A, the outer layer (A ), The intermediate layer (B) and the inner layer (C) had a thickness ratio of 1/4/1 and an agricultural film having a total thickness of 150 μm.

(Comparative Example 1)
Instead of ethylene-vinyl acetate copolymer A, ethylene-vinyl acetate copolymer B (density: 0.938 g / cm ³ , MFR: 1.0 g / 10 min, vinyl acetate content: 15% by weight) 2 The thickness ratio of the outer layer (A), the intermediate layer (B), and the inner layer (C) was 1/4/1 and the total thickness was 150 μm in the same manner as in Example 1 except that it was supplied to the extruder. Agricultural film was obtained.

(Example 4 )
Instead of ethylene-vinyl acetate copolymer A, ethylene-vinyl acetate copolymer C (density: 0.948 g / cm ³ , MFR: 3.0 g / 10 min, vinyl acetate content: 30% by weight) 2 The thickness ratio of the outer layer (A), the intermediate layer (B), and the inner layer (C) was 1/4/1 and the total thickness was 150 μm in the same manner as in Example 1 except that it was supplied to the extruder. Agricultural film was obtained.

(Example 5 )
Magnesium - instead of aluminum complex hydroxide salt, inorganic fine particles B, Li - implementation except that the aluminum complex hydroxide salt (water Sawa Chemical Co., trade name "Mizukarakku") was fed to the second extruder In the same manner as in Example 1, an agricultural film having an outer layer (A), intermediate layer (B), and inner layer (C) thickness ratio of 1/4/1 and a total thickness of 150 μm was obtained.

(Example 6 )
Instead of linear low density polyethylene A, linear low density polyethylene B (polymerization catalyst: Ziegler catalyst, α-olefin: 1-octene, density: 0.90 g / cm ³ , MFR: 1.5 g / 10 Min) was supplied to the first and third extruders in the same manner as in Example 1, and the thickness ratio of the outer layer (A), the intermediate layer (B), and the inner layer (C) was 1/4. / 1 and a total film thickness of 150 μm was obtained.

(Example 7 )
Instead of linear low density polyethylene A, linear low density polyethylene C (polymerization catalyst: Ziegler catalyst, α-olefin: 1-octene, density: 0.920 g / cm ³ , MFR: 1.5 g / 10 Min) was supplied to the first and third extruders in the same manner as in Example 1, and the thickness ratio of the outer layer (A), the intermediate layer (B), and the inner layer (C) was 1/4. / 1 and a total film thickness of 150 μm was obtained.

(Example 8 )
Linear low-density polyethylene D instead of linear low-density polyethylene A (polymerization catalyst: metallocene catalyst, α-olefin: 1-octene, density: 0.915 g / cm ³ , MFR: 1.0 g / 10 minutes ) In the same manner as in Example 1 except that the thickness ratio of the outer layer (A), the intermediate layer (B), and the inner layer (C) is 1/4 / An agricultural film having a thickness of 1 and a total thickness of 150 μm was obtained.

( Comparative Example 8 )
Linear low density polyethylene E instead of linear low density polyethylene A (polymerization catalyst: Ziegler catalyst, α-olefin: 1-hexene, density: 0.915 g / cm ³ , MFR: 1.5 g / 10 minutes ) In the same manner as in Example 1 except that the thickness ratio of the outer layer (A), the intermediate layer (B), and the inner layer (C) is 1/4 / An agricultural film having a thickness of 1 and a total thickness of 150 μm was obtained.

( Comparative Example 9 )
Instead of linear low density polyethylene A, linear low density polyethylene F (polymerization catalyst: Ziegler catalyst, α-olefin: 1-butene, density: 0.915 g / cm ³ , MFR: 1.5 g / 10 Min) was supplied to the first and third extruders in the same manner as in Example 1, and the thickness ratio of the outer layer (A), the intermediate layer (B), and the inner layer (C) was 1/4. / 1 and a total film thickness of 150 μm was obtained.

( Comparative Example 10 )
Instead of linear low density polyethylene A, linear low density polyethylene G (polymerization catalyst: metallocene catalyst, α-olefin: 1-hexene, density: 0.915 g / cm ³ , MFR: 1.0 g / 10 Min) was supplied to the first and third extruders in the same manner as in Example 1, and the thickness ratio of the outer layer (A), the intermediate layer (B), and the inner layer (C) was 1/4. / 1 and a total film thickness of 150 μm was obtained.

(Comparative Example 2)
Implemented except that 99 parts by weight of ethylene-vinyl acetate copolymer A instead of 90 parts by weight and 1 part by weight of magnesium-aluminum composite hydroxide salt instead of 10 parts by weight were fed to the second extruder. In the same manner as in Example 1, an agricultural film having an outer layer (A), intermediate layer (B), and inner layer (C) thickness ratio of 1/4/1 and a total thickness of 150 μm was obtained.

(Comparative Example 3)
Implemented except that 70 parts by weight of ethylene-vinyl acetate copolymer A instead of 90 parts by weight and 1 part by weight of magnesium-aluminum composite hydroxide salt instead of 30 parts by weight were fed to the second extruder. In the same manner as in Example 1, an agricultural film having an outer layer (A), intermediate layer (B), and inner layer (C) thickness ratio of 1/4/1 and a total thickness of 150 μm was obtained.

(Comparative Example 4)
Instead of linear low density polyethylene A, 50 parts by weight of linear low density polyethylene A and 50 parts by weight of low density polyethylene A were supplied to the first extruder, and linear low density polyethylene A was supplied to the third extruder. The outer layer (A), the intermediate layer (B), and the inner layer were the same as in Example 1 except that 50 parts by weight of 80 parts by weight and 50 parts by weight of low density polyethylene A instead of 20 parts by weight were supplied. An agricultural film having a thickness ratio of (C) of 1/4/1 and a total thickness of 150 μm was obtained.

(Comparative Example 5)
Instead of ethylene-vinyl acetate copolymer A, ethylene-vinyl acetate copolymer D (density: 0.925 g / cm ³ , MFR: 1.0 g / 10 min, vinyl acetate content: 5% by weight) 2 The thickness ratio of the outer layer (A), the intermediate layer (B), and the inner layer (C) was 1/4/1 and the total thickness was 150 μm in the same manner as in Example 1 except that it was supplied to the extruder. Agricultural film was obtained.

(Comparative Example 6)
Instead of ethylene-vinyl acetate copolymer A, ethylene-vinyl acetate copolymer E (density: 0.945 g / cm ³ , MFR: 3.5 g / 10 min, vinyl acetate content: 35% by weight) 2 The thickness ratio of the outer layer (A), the intermediate layer (B), and the inner layer (C) was 1/4/1 and the total thickness was 150 μm in the same manner as in Example 1 except that it was supplied to the extruder. Agricultural film was obtained.

(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.) as a solid content, and 1 part by weight of colloidal alumina (trade name “Alumina Sol 100” manufactured by Nissan Chemical Industries, Ltd.) as a solid content And 2 parts by weight of polyethylene oxide (manufactured by Sumitomo Seika Co., Ltd.) as a solid content was added and mixed to obtain an anti-fogging drop agent in which colloidal silica and colloidal alumina were dispersed in water containing polyethylene oxide. .

(Formation of anti-fogging droplet layer)
The antifogging drop obtained as described above was applied to the surface of the inner layer (C) of the agricultural film obtained in Examples 1 to 11 and Comparative Examples 1 to 7, and the coating amount before drying was 10 g / It was applied with a gravure coater so as to be m ² and dried with hot air to form an anti-fogging 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.

(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.
○: The film for agriculture was slightly non-uniform in 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 overlap | superposed from the thermostatic chamber was taken out, two films were peeled, and blocking property evaluation was performed on the following reference | standard.
A: The two films were not blocked and could be easily peeled off.
○: The two films were slightly blocked, but there was no difficulty in peeling them off.
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 Co., Ltd.), and the tear strength was evaluated according to the following criteria.
A: Tear strength was 15 N or more.
○: 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.
A: Impact strength was 2.5 J or more.
○: Impact strength was 1.5 J or more and less than 2.5 J.
X: The impact strength was less than 1.5 J.

(Heat retention)
The absorption spectrum of an agricultural film was measured using an infrared spectrophotometer (trade name “FT / IR-410” manufactured by JASCO Corporation), and the spectral radiant divergence radiated from the ground (1 ) Was weighted to calculate the spectral radiant divergence (2), and the thermal insulation properties of the agricultural film were evaluated according to the following criteria from the spectral radiant divergence (1) and the corrected spectral radiant divergence (2).
A: The heat retention was 80% or more.
○: The heat retention was 50% or more and less than 80%.
X: The heat retention was less than 50%.

(transparency)
The haze value of the agricultural film immediately after production was measured with a haze meter (trade name “MDH2000” manufactured by Nippon Denshoku Industries Co., Ltd.), and the transparency was evaluated according to the following criteria.
A: Haze value was less than 15%.
○: Haze value was 15% or more and less than 25%.
X: Haze value was 25% or more.

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. 920g / cm ^3, melt mass flow Rei door 0. With a copolymer in which linear low density polyethylene containing 80% or more by weight resin composition of the Ah Ri and ethylene and 1-octene in 3~5.0g / 10 min, the intermediate layer (B) Is an ethylene-vinyl acetate copolymer having a vinyl acetate component content of 18-30% by weight and a melt mass flow rate of 0.5-4.0 g / 10 min, and Mg, Al, Ca, Zn, Si. And an agricultural film comprising a resin composition containing 3 to 20% by weight of inorganic particles containing at least one atom selected from the group consisting of Li and Li. Claims to the surface of the inner layer (C), characterized in that the colloidal silica and / or anti-fogging flow drops layer formed from antifogging flow drops the colloidal alumina is are contained is provided in an aqueous medium The agricultural film as described in 1 .