JP2006014689A - Agricultural film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prepare an agricultural film excellent in mechanical strengths, heat retaining property and weather-resistance, having excellent tolerance to chemical agents such as fertilizer and agrochemicals and suitably usable for a long period. <P>SOLUTION: This agricultural film contains 0.05-5 pt(s). wt. of a light stabilizer having in one molecule at least one substituent shown by the formula and 1-15 pt(s). wt. of hydrotalcite or lithium aluminium composite hydroxide based on 100 pts. wt. of an ethylene-based resin, and has a thickness of 50-200 μm. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to an agricultural film used in an agricultural crop cultivation facility, and more particularly to an agricultural film suitably used as an outer layer of an agricultural house that uses chemicals such as fertilizers and agricultural chemicals in the cultivation facility.

In general, vinyl chloride resin films, ethylene resin films, and the like are used as agricultural films used in crop cultivation facilities.
Among them, vinyl chloride resin films that have been widely used in the past are excellent in heat retention, weather resistance, transparency, workability, etc., but generation of toxic gas when incinerating waste after use. In recent years, the amount used has decreased.

In recent years, the amount of ethylene resin film used has rapidly increased as an agricultural film that can replace these vinyl chloride resin films. This ethylene resin film has many advantages over the vinyl chloride resin film, such as weight reduction, price, processability, mechanical strength, and ease of disposal.
However, since it is deteriorated due to ultraviolet rays or heat, that is, in terms of weather resistance, when used outdoors, various improvements have been made to enable outdoor use in areas where the use conditions are severe over a long period of time. Yes.

For example, Patent Document 1 and Patent Document 2 disclose that an olefin resin film containing a hindered amine light stabilizer can improve weather resistance.
Furthermore, Patent Document 2 discloses that an olefin resin film containing a lithium aluminum composite hydroxide salt in addition to the hindered amine light stabilizer can be used over a long period of time.

JP 59-86645 A JP 7-312996 A

However, in the olefin-based resin film containing lithium aluminum composite hydroxide salt or the like as in Patent Document 2, sulfur and chlorine generated from acidic substances contained in chemicals such as fertilizers and agricultural chemicals in the cultivation facility, Since it is adsorbed by a heat insulating agent such as a lithium aluminum composite hydroxide salt, there has been a problem of further promoting the deterioration of the film. Another object of the present invention is to provide an agricultural film that is excellent in weather resistance, has good resistance to chemicals such as fertilizers and agricultural chemicals, and can be suitably used for a long period of time.

また、本発明による農業用フィルムにおいては、無機保温剤が、ハイドロタルサイト又はリチウムアルミニウム複合水酸化物から選ばれる少なくとも１つを含有していることが
好ましい。
以下に本発明の詳細について説明する。 In the agricultural film according to the present invention, 0.05 to 5 parts by weight of a light stabilizer having at least one substituent represented by the general formula (1) in the molecule and inorganic heat retention with respect to 100 parts by weight of the ethylene-based resin. 1 to 15 parts by weight of the agent is contained, and the thickness is 50 to 200 μm.

Moreover, in the agricultural film by this invention, it is preferable that the inorganic heat retention agent contains at least 1 chosen from a hydrotalcite or a lithium aluminum composite hydroxide.
Details of the present invention will be described below.

  The ethylene-based resin according to the present invention is not particularly limited, and examples thereof include ethylene-based resins generally used for agricultural films; polyethylenes such as low-density polyethylene, medium-density polyethylene, and high-density polyethylene; Ethylene-α-olefin copolymers such as propylene, 1-butene, 4-methyl-1-pentene, 1-hexene, 1-octene; ethylene-vinyl acetate copolymers are preferred, ethylene-vinyl acetate copolymer Coalescence is more preferred.

（式中、ｎは１〜２０の整数を表し、基Ｒ１は互いに独立しているが、少なくとも１ つは−Ｏ・基であり、それ以外は水素原子、炭素原子数１〜８のアルキル基、−Ｏ Ｈ基、−ＣＨ２ＣＮ基、炭素原子数１〜１８のアルコキシ基、炭素原子数５〜１２ のシクロアルコキシ基、炭素原子数３〜６のアルケニル基、非置換もしくは１〜３ 個の炭素原子数１〜４のアルキル基によりフェニル環が置換された炭素原子数７〜 ９のフェニルアルキル基、または炭素原子数１〜８のアシル基を表し、基Ｒ２はＲ １に対して定義された意味のうちの1つを表わし、Ｘは炭素原子数２〜１０のアル キレン基を表わし、ＹはＯ基又はＮＨ基を表わす） The light stabilizer according to the present invention needs to have at least one substituent represented by the general formula (1) in the molecule, and examples thereof include compounds represented by the following general formula (2).

(In the formula, n represents an integer of 1 to 20 and the groups R1 are independent of each other, but at least one is —O · group, and other than that, a hydrogen atom and an alkyl group having 1 to 8 carbon atoms) , —OH group, —CH 2 CN group, alkoxy group having 1 to 18 carbon atoms, cycloalkoxy group having 5 to 12 carbon atoms, alkenyl group having 3 to 6 carbon atoms, unsubstituted or 1 to 3 carbons Represents a phenylalkyl group having 7 to 9 carbon atoms in which the phenyl ring is substituted by an alkyl group having 1 to 4 atoms or an acyl group having 1 to 8 carbon atoms, and the group R2 is defined with respect to R1 One of the meanings, X represents an alkylene group having 2 to 10 carbon atoms, and Y represents an O group or an NH group)

  The content of the light stabilizer is 0.05 to 5 parts by weight with respect to 100 parts by weight of the ethylene resin. If the content is less than 0.05 parts by weight, agricultural chemical resistance and ultraviolet resistance cannot be expressed. Conversely, if the content exceeds 5 parts by weight, the light stabilizer tends to bleed and the transparency of the film is poor. Become.

  In the agricultural film according to the present invention, in addition to the light stabilizer, any conventionally known hindered amine compound may be used in combination, and these compounds are not particularly limited. Specifically, dimethyl succinate-1- (2-hydroxyethyl) -4-hydroxy-2,2,6,6-tetramethylpiperidine polycondensate, tetrakis (2,2,6,6-tetramethyl- 4-piperidyl) -1,2,3,4-butanetetracarboxylate, poly {[6-[(1,1,3,3-tetramethylbutyl) amino] -1,3,5-triazine-2, 4-diyl] [(2,2,6,6-tetramethyl-4-piperidyl) imino] hexamethylene [(2,2,6,6-tetramethyl-4-piperidyl) imino]} and the like.

  In the present invention, the inorganic heat insulating agent is not particularly limited, but hydrotalcite or lithium aluminum composite hydroxide is preferably used. As the hydrotalcite, for example, DHT- manufactured by Kyowa Chemical Industry Co., Ltd. In addition, examples of the lithium aluminum composite hydroxide include Mizusawa Chemical Industry Co., Ltd., Mizukarak, Fuji Chemical Co., Ltd., Fujirain LS, and the like.

  The content of the hydrotalcite or lithium aluminum composite hydroxide is 1 to 15 parts by weight with respect to 100 parts by weight of the ethylene resin. When the content is less than 1 part by weight, the heat retaining property is insufficient. Conversely, when the content exceeds 15 parts by weight, the film becomes white and the transparency is deteriorated.

  The agricultural film according to the present invention has a thickness of 50 to 200 μm, preferably 100 to 150 μm. If the thickness is less than 50 μm, the mechanical strength of the film is lowered. Conversely, if the thickness is more than 200 μm, cutting, joining, stretching work and the like are difficult, and handling properties are lowered.

  The agricultural film of the present invention contains additives such as, for example, a heat stabilizer, an antioxidant, an ultraviolet absorber, an antifoggant, a lubricant, etc., as necessary, as long as the achievement of the object of the present invention is not hindered. May be.

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

  The antioxidant is not particularly limited, but usually there are many that have the effect as the heat stabilizer, for example, metal salts of carboxylic acids, phenolic antioxidants, organic phosphites. And the like. These heat stabilizers may be used alone or in combination of two or more.

  The ultraviolet absorber is not particularly limited, and for example, benzophenone-based, benzotriazole-based, salicylic acid ester-based, cyanoacrylate-based ultraviolet absorbers may be used alone or in combination of two or more. it can. Specifically, as the benzophenone-based ultraviolet absorber, 2,4-dihydroxybenzophenone, 2-hydroxy-4-octoxybenzophenone, 2-hydroxy-4-dodecyloxybenzophenone, 2,2′-dihydroxy-4-methoxy As benzotriazole ultraviolet absorbers such as benzophenone, 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-chloro Benzotriazole, 2- (2′-hydroxy-3 ′, 5 - di -tert- butylphenyl) -5-chloro-benzotriazole, 2- (2'-hydroxy-3 ', 5'-di -tert- amylphenyl) -5-chloro-benzotriazole, and the like. These ultraviolet absorbers may be used alone or in combination of two or more.

  The 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. .

  The agricultural film of the present invention is kneaded with an anti-fogging agent as necessary in order to allow water droplets condensed on the inner surface to flow when being spread on an agricultural house, etc. A film may be formed. The antifogging agent to be kneaded into the agricultural film is not particularly limited. Examples thereof include polyhydric alcohol unsaturated fatty acid esters such as saturated fatty acid esters, glycerin oleate and diglycerin oleate.

Further, as the antifogging film formed on the inner surface of the farm film, for example, a coating film of an inorganic oxide sol represented by colloidal silica or colloidal alumina, or an application thereof, an interface with an inorganic oxide sol Coating film with an organic compound such as an activator or a resin, a liquid coating film containing a surfactant as a main component, a film containing a hydrophilic resin as a main component (eg, polyvinyl alcohol, polyethylene oxide, polysaccharide, polyacrylic) Acid, etc.).
Examples of methods for forming these antifogging coatings include a roll coating method such as a gravure coater, a barcode method, a dip coating method, a spray method, and a brush coating method.

  As the method for forming an agricultural film according to the present invention, any conventionally known method may be employed, and examples thereof include an inflation method, a T-die extrusion method, an extrusion laminating method, and a calendar method.

  The agricultural film according to the present invention may be composed of a single layer, but is preferably laminated in a plurality of layers.

  The agricultural film of the present invention has the structure as described above, is excellent in mechanical strength, heat retention and weather resistance, has good resistance to chemicals such as fertilizers and agricultural chemicals, and is a facility for agricultural products over a long period of time. It can be suitably used for cultivation.

  EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples, but the present invention is not limited only to these examples.

1. Production of Agricultural Film The following resin compositions (A, B, C), light stabilizers, and inorganic heat-retaining agents are blended in proportions (parts by weight) shown in Tables 1 and 2, and resin compositions (A , B, C) Each is put into another extruder, melt-kneaded, and three layers are co-extruded by an inflation method so as to be laminated in that order, and the thickness ratio of each layer is 1: 7: 2, A film having a total thickness of 30 to 150 μm was obtained.
(1) Resin composition A: 70 parts by weight of linear low density polyethylene (MI 2.1 g / 10 min, density 0.92 g / cm ³ ), low density polyethylene (MI 2.1 g / 10 min, density 0.92 g) / Cm ³ ) 30 parts by weight.
B: 100 parts by weight of ethylene-vinyl acetate copolymer (vinyl acetate content 15% by weight, MI 1.0 g / 10 min, density 0.93 g / cm ³ ).
C: 100 parts by weight of ethylene-vinyl acetate copolymer (vinyl acetate content 5% by weight, MI 1.0 g / 10 min, density 0.93 g / cm ³ ).
In addition, said MI means the melt index measured by the temperature of 190 degreeC and the load of 21.18N based on JISK7210.

(2) Light stabilizer • Tinuvin 371: At least one of R _{1 in} the general formula (2) is R ₁ = —O.
Made by Ciba Specialty Chemicals.
Kimasolve 119: R ₁ = —CH _{3 of} the above general formula (2), manufactured by Ciba Specialty Chemicals.
Kimasolve 944: R ₁ = −H in the above general formula (2), manufactured by Ciba Specialty Chemicals.

(3) Inorganic warming agent DHT-4A: Hydrotalcite, manufactured by Kyowa Chemical Industry Co., Ltd.
・ Mizukarak: Lithium aluminum composite hydroxide, manufactured by Mizusawa Chemical Industry Co., Ltd.
Micromag 3-150: Magnesium oxide, manufactured by Kyowa Chemical Industry Co., Ltd.

Next, 5 parts by weight of colloidal silica (manufactured by Nissan Chemical Industries, Ltd., trade name “ST-PSM”) and colloidal alumina (Nissan Chemical Industry) are added to 100 parts by weight of water on the C layer side of the film obtained above. Anti-fogging obtained by adding 1 part by weight of a product name “Alumina Sol 100”) and 2 parts by weight of polyethylene oxide (trade name “PEO-1Z”, manufactured by Sumitomo Seika Co., Ltd.) The agent was applied with a gravure coater so as to have an application amount of 10 g / cm ² , and then dried with hot air to form an antifogging film to obtain agricultural films of Examples and Comparative Examples. In addition, although the said colloidal silica and colloidal alumina were added as a water dispersion liquid, the said addition amount is the quantity of solid content, and the water | moisture content in a dispersion liquid is contained in 100 weight part of water.

2. Performance evaluation The performance of the agricultural film obtained in the above was evaluated by the following method. The results were as shown in Tables 1 and 2.

(1) Breaking point load Using a strograph manufactured by Toyo Seiki Seisakusho, breaking point strength was measured according to JIS K 6781, and breaking point load was evaluated according to the following criteria.
○: Fracture occurred at a load of 3000 g or more.
(Triangle | delta): It fractured | ruptured with the load of 1000 g or more and less than 3000 g.
X: Fracture occurred at a load of less than 1000 g.

(2) Thermal insulation The absorption spectrum of the film is measured using an infrared spectrophotometer (manufactured by JASCO Corporation, FT / IR-410), and the spectral radiant divergence (1 ) Was weighted to calculate the spectral radiant divergence (2), and the heat retention was evaluated according to the following criteria from the spectral radiant divergence (1) and the corrected spectral radiant divergence (2).
○: Thermal insulation is 80% or more △: Thermal insulation is 50% or more and less than 80% ×: Thermal insulation is less than 50%

(3) Chemical resistance A 15 cm long x 15 cm agricultural film sample was immersed in 1N sulfuric acid for 7 days, and then irradiated with 50 W / cm ² ultraviolet rays for 48 hours with an ultraviolet lamp. The sample after irradiation was measured for the elongation at break according to JIS K 6781, and the chemical resistance was evaluated according to the following criteria.
○: Remaining elongation at break 500% or more Δ: Remaining elongation at break 200% or more and less than 500% ×: Remaining elongation at break less than 200%

(4) Transparency The haze value was measured using a Nippon Denshoku Industries Co., Ltd. haze measuring machine MDH2000, and the transparency was evaluated according to the following criteria.
○: Haze value is less than 15% Δ: Haze value is 15% or more and less than 25% ×: Hase value is 25% or more

Claims (2)

0.05 to 5 parts by weight of a light stabilizer having at least one substituent represented by the general formula (1) in the molecule and 1 to 15 parts by weight of an inorganic heat retention agent per 100 parts by weight of the ethylene resin Agricultural film having a thickness of 50 to 200 μm.

2. The agricultural film according to claim 1, wherein the inorganic heat retaining agent contains at least one selected from hydrotalcite or lithium aluminum composite hydroxide.