JP6731100B1 - Method for improving the ability of agricultural films to suppress sulfur absorption - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an agricultural film excellent in long-term weather resistance and transparency. SOLUTION: The agricultural film of the present invention comprises a layer containing a predetermined hindered amine light stabilizer and a synergist containing one or more selected from a predetermined benzoate compound, and has a sulfur uptake amount of ΔW. When the thickness of the agricultural film is H1 and the thickness of the layer is H2, (ΔW×(H2/H1))/H2 is 2.80 ppm/μm or more and 4.70 ppm/μm or less and is 290 nm. When the light transmittance is T290 and the light transmittance at 340 nm is T340, T290/T340 satisfies 0.76 or more and 1.00 or less. [Selection diagram] Figure 1

Description

The present invention relates to an improved how sulfur absorption inhibiting ability of agricultural films.

Various developments have been made so far for agricultural films. As this type of technology, for example, the technology described in Patent Document 1 is known. Patent Document 1 describes an agricultural film containing a hindered amine-based light stabilizer (such as claim 4 of Patent Document 1).

JP-A-2015-198579

However, as a result of examination by the present inventors, it was found that there is room for improvement in terms of long-term weather resistance and transparency in the agricultural film described in Patent Document 1.

In agricultural work, a growing method such as a sulfur fumigation method or a spraying method of a sulfur-containing chemical liquid such as a sulfur flowable agent may be adopted for the purpose of preventing diseases of plants (crops).
However, fumigation and sulfur contained in the chemical liquid may reduce the weather resistance of the agricultural film.

As a result of intensive studies in view of such circumstances, the present inventor provided a layer containing these by using a predetermined hindered amine light stabilizer and a predetermined benzoate compound as a synergist thereof. It was found that the deterioration of weather resistance was suppressed in the agricultural film. Although the detailed mechanism is not clear, since the synergist suppresses the salt formation between sulfur and the hindered amine light stabilizer, it is possible to suppress the incorporation and absorption of sulfur in the agricultural film. Conceivable.

According to the present invention,
To the hindered amine light stabilizer, by adding a benzoate compound as its synergist, to improve the sulfur absorption suppressing ability in the agricultural film, a method of improving the sulfur absorption suppressing ability of the agricultural film ,
The hindered amine light stabilizer contains at least one of a compound represented by the following chemical formula A1 and a compound represented by the following chemical formula A2,
The synergist contains one or more selected from benzoate compounds represented by the following general formula (B):
When the mass-converted addition amount of the hindered amine light stabilizer is A and the synergist mass-added amount is B, A and B are 0.2/0.8≦A/B≦0. Meets 95/0.05,
Provided is a method for improving the ability of an agricultural film to suppress sulfur absorption .

According to the present invention, improved how sulfur absorption inhibiting ability of agricultural films capable of improving the sulfur absorption suppressing ability is provided in agricultural films.

It is sectional drawing which shows an example of a structure of the agricultural film of this embodiment. It is a figure for explaining the outline of the fumigation equipment used for sulfur fumigation processing. It is a figure explaining the procedure of the pretreatment of the test piece used as the measuring object of light transmittance. It is a figure for demonstrating the outline of the measurement principle of the light transmittance of the test piece using a spectrophotometer.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all the drawings, the same constituents will be given the same reference numeral, and the description thereof will not be repeated. Moreover, the figure is a schematic view and does not match the actual dimensional ratio.
In this embodiment, the front, rear, left, right, up, and down directions are defined as shown in the figure. However, this is provided for convenience in order to briefly describe the relative relationship of the components. Therefore, it does not limit the direction in which the product embodying the present invention is manufactured or used.

The agricultural film of this embodiment will be described.
The agricultural film of the present embodiment has a hindered amine light stabilizer selected from at least one of the compound represented by the following chemical formula A1 and the compound represented by the following chemical formula A2, and the following general formula (B). And a synergist containing one or more selected from the benzoate compounds represented by the following (hereinafter, referred to as a weather resistant layer).

The weather resistant layer may include at least one of the hindered amine light stabilizers represented by the following chemical formula A1 or chemical formula A2.

上記化学式Ａ１中、ｎの数値は、０〜１０でもよく、０〜６でもよい。ヒンダードアミン系光安定剤は、ｎが異なる化学式Ａ１で表される化合物を複数含んでもよい。

In the chemical formula A1, the numerical value of n may be 0 to 10 or 0 to 6. The hindered amine light stabilizer may include a plurality of compounds represented by the chemical formula A1 in which n is different.

The weather resistant layer may contain at least one benzoate compound represented by the following general formula (B) as a synergist. These may be used alone or in combination of two or more.

In the general formula (B), R ⁵ and R ⁶ are each independently an alkyl group having 1 to 8 carbon atoms, R ⁷ is an alkyl group having 1 to 30 carbon atoms, and an aryl group having 6 to 30 carbon atoms. Or an alkylaryl group having 7 to 30 carbon atoms.

Examples of the alkyl group having 1 to 8 carbon atoms of R ⁵ and R ⁶ include methyl, ethyl, propyl, isopropyl, butyl, sec-butyl, tert-butyl, pentyl, tert-pentyl, hexyl, heptyl, octyl, 1, 1,3,3-tetramethylbutyl and the like can be mentioned.

Examples of the alkyl group having 1 to 30 carbon atoms of R ⁷ include methyl, ethyl, propyl, butyl, pentyl, hexyl, heptyl, octyl, 2-ethylhexyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pentadecyl, hexadecyl. , Heptadecyl, octadecyl and the like.

Examples of the aryl group of R ⁷ include phenyl and the like.
Examples of the alkylaryl group for R ⁷ include methylphenyl, butylphenyl, 2,4-ditertiary butylphenyl, 2,4-ditertiary amylphenyl, 2,4-dicumylphenyl and 2,4-ditertiary. Butyl-5-methylphenyl and the like can be mentioned. Phenylmethyl is mentioned as an arylalkyl group.

In addition, R ⁷ in the general formula (B) may be an arylalkyl group having ^{7 to} 30 carbon atoms, and specifically may be an arylalkyl group such as phenylmethyl.

Examples of the benzoate compound represented by the general formula (B) include the following compound No. 7-15 etc. are mentioned. These may be used alone or in combination of two or more.
However, it is not limited to the following compounds.

Among the above, the benzoate compound represented by the general formula (B) may include at least one of the following compound B1 or compound B2.

The weather resistant layer of the agricultural film may include a thermoplastic resin.

Examples of the thermoplastic resin include polypropylene, high-density polyethylene, low-density polyethylene, linear low-density polyethylene, polybutene-1, poly-4-methylpentene, and other α-olefin polymers, ethylene-vinyl acetate copolymers, ethylene- Polyolefins such as vinyl alcohol copolymers, ethylene-acrylic acid ester copolymers, ethylene-propylene copolymers and their copolymers, polyvinyl chloride, polyvinylidene chloride, chlorinated polyethylene, chlorinated polypropylene, polyvinylidene fluoride , Rubber chloride, vinyl chloride-vinyl acetate copolymer, vinyl chloride-ethylene copolymer, vinyl chloride-vinylidene chloride copolymer, vinyl chloride-vinylidene chloride-vinyl acetate terpolymer, vinyl chloride-acrylic acid ester Halogen-containing resins such as copolymers, vinyl chloride-maleic acid ester copolymers, vinyl chloride-cyclohexylmaleimide copolymers, petroleum resins, coumarone resins, polystyrene, polyvinyl acetate, acrylic resins, styrene and/or α-methyl Copolymers (for example, AS resin, ABS resin, MBS resin, heat-resistant ABS resin, etc.) of styrene and other monomers (for example, maleic anhydride, phenylmaleimide, methyl methacrylate, butadiene, acrylonitrile, etc.), poly Linear polyesters such as methyl methacrylate, polyvinyl alcohol, polyvinyl formal, polyvinyl butyral, polyethylene terephthalate and polytetramethylene terephthalate, polyamides such as polyphenylene oxide, polycaprolactam and polyhexamethylene adipamide, polycarbonate, branched polycarbonate, polyacetal, polyphenylene sulfide. , Thermoplastic resins such as polyurethane and fibrin-based resins, and mixtures thereof, or phenol resins, urea resins, melamine resins, epoxy resins, unsaturated polyester resins and the like. These may be used alone or in combination of two or more. Among these, polyolefin resins such as polyethylene, ethylene-vinyl acetate copolymer, ethylene-vinyl alcohol copolymer, and ethylene-acrylic acid ester copolymer may be used.

Further, as the thermoplastic resin, an α-olefin polymer, a blended product or a copolymer of polyethylene and another α-olefin polymer, an α-olefin polymer such as polyethylene and an ethylene-vinyl acetate copolymer, ethylene- Blends or copolymers with polyolefins such as propylene copolymers may be used.
Among these, the thermoplastic resin may include at least one of linear low-density polyethylene and low-density polyethylene.

The lower limit of the content of the hindered amine light stabilizer and the synergist (benzoate compound) in the weather resistant layer is, for example, 0.01 parts by mass or more, preferably 0.2 parts by mass, relative to 100 parts by mass of the thermoplastic resin. The above is more preferably 0.8 parts by mass or more. On the other hand, the upper limit is, for example, 10 parts by mass or less, preferably 3 parts by mass or less, and more preferably 1 part by mass or less. Light resistance can be improved by setting it as such a range.

The content of the hindered amine light stabilizer in the weather resistant layer is A, and the content of the synergist is B.
At this time, A and B in the weather resistant layer are, for example, 0.2/0.8≦A/B≦0.95/0.05, preferably 0.3/0.7≦A/B≦0. 0.7/0.3, more preferably 0.4/0.6≦A/B≦0.6/0.4 may be satisfied. By setting A/B to the upper limit value or less, long-term light resistance can be improved. By setting A/B to the above lower limit or more, transparency and long-term light resistance can be improved.

The weather resistant layer is a hindered amine-based light stabilizer, a benzoate compound as a synergist, and a thermoplastic resin, in addition to the hindered effects of the present invention, other commonly used in agricultural films. You may include an additive. The other additives may be configured not to include a benzophenone-based, benzotriazole-based, or triazine-based ultraviolet absorber.

The thickness of the agricultural film 100 is not particularly limited, but is, for example, 10 μm to 1 mm, preferably 30 μm to 500 μm, and more preferably 50 μm to 300 μm.

FIG. 1 is a cross-sectional view showing an example of the configuration of the agricultural film of this embodiment.
The agricultural film 100 of FIG. 1A includes at least one layer (the weather resistant layer 10) containing the hindered amine light stabilizer and the synergist described above. The agricultural film 100 may include a single or a plurality of weather resistant layers 10 in the thickness direction.

In addition, the agricultural film 100 may be composed of a multilayer film having one or more other layers (base layer 20) in addition to the weather resistant layer 10, as shown in FIG. 1( b ). The multilayer film may have two or more layers, for example, three layers, four layers, five layers or more, and seven layers or more. The upper limit of the number of layers of the multilayer film is not particularly limited, but may be, for example, 10 layers or less.

Further, the base layer 20 may be provided on one surface of the weather resistant layer 10, and the base layer 20 and the surface layer may be provided as other layers on each of the one surface and the other surface of the weather resistant layer 10. Unlike the weather-resistant layer 10, the other layer may have a configuration that does not include both the hindered amine light stabilizer and the synergist described above, and may include only one of them, but both of them may be included. It may not be included.

The other layer may be composed of the above-mentioned thermoplastic resin, and may contain the following other additives as necessary. As the thermoplastic resin for the other layer, for example, linear low-density polyethylene, low-density polyethylene, etc. may be used.

General agricultural films are used in various scenes such as materials for forming greenhouses.
In agricultural work, for the purpose of preventing diseases of plants (crop crops), there are cases in which a growing method such as a method of fumigating sulfur in a greenhouse or a method of spraying a plant with a chemical solution containing sulfur is used.

However, fumigation and sulfur contained in the chemical liquid may reduce the weather resistance of the agricultural film.

The detailed mechanism is not clear, but the sulfur attached to or transferred to the agricultural film is oxidized and acidified, forming a salt with the hindered amine light stabilizer, and the function of the light stabilizer. It is thought that the weather resistance cannot be maintained because it is deactivated.
In addition, such a phenomenon of deterioration of weather resistance is remarkably observed when sulfur fumigation is performed in a greenhouse.

As a result of intensive studies in view of such circumstances, the present inventor has found that by using a predetermined hindered amine-based light stabilizer in combination with a predetermined benzoate compound as a synergist, an agriculture provided with a layer containing these is provided. It was found that the deterioration of the weather resistance of the film for use was suppressed. At this time, it was found that the characteristic that the sulfur was hardly absorbed inside the agricultural film was developed.

Although the detailed mechanism is not clear, since the synergist suppresses the salt formation between sulfur and the hindered amine light stabilizer, it is possible to suppress the incorporation and absorption of sulfur in the agricultural film. Conceivable.
From the above, the present inventor has found out a new characteristic of the agricultural film that is the ability to suppress sulfur absorption.

As a result of repeated studies based on such findings, the degree of difficulty in absorbing sulfur in the agricultural film 100 (that is, the amount of sulfur taken up) is used as an index to stably stabilize the long-term light resistance of the agricultural film 100. It turns out that it can be evaluated. Then, as an index of the sulfur uptake amount, when the sulfur uptake amount measured according to the following procedure A is ΔW, the thickness of the agricultural film 100 is H1, and the thickness of the weather resistant layer 10 is H2, (ΔW×(H2/ It has been found that the long-term weather resistance and transparency can be improved by adopting (H1))/H2 and setting the upper and lower limits of such an index within appropriate ranges.

In such an agricultural film 100, when the light transmittance at ₂₉₀ nm is T ₂₉₀ and the light transmittance at 340 nm is T ₃₄₀ measured according to the following procedure B, T ₂₉₀ /T ₃₄₀ is set to a predetermined value or more. As a result, an agricultural film suitable for growing plants such as agricultural crops can be realized.

Hereinafter, the procedure A for calculating ΔW (sulfur uptake amount) of the agricultural film 100 will be described.
<Procedure A>
Procedure A1: Using the agricultural film 100, according to the following order of (1), (2), (4), and (5), the content of the elemental sulfur in the agricultural film 100 before the sulfur fumigation treatment ( (ppm) is measured, and this measured value is designated as S ₀ .
Procedure A2: Using the agricultural film 100 to be measured in Procedure A1, according to the following order of (1), (2), (3), (4), and (5), agriculture after sulfur fumigation treatment: The content (ppm) of the elemental sulfur in the film for use 100 is measured, and this measured value is defined as S ₁ . However, S ₁ is an average value of four measured values.
Procedure A3: Using the S ₀ obtained in the above procedure A1 and the S ₁ obtained in the procedure A2, calculate the sulfur uptake amount (ppm) of the agricultural film 100 based on the following formula (I). ..
|S ₁ -S ₀ | Equation (I)

(1): Preparation of test piece The agricultural film 100 is cut out to prepare a strip-shaped film test piece A having a length of 13 cm and a width of 2.5 cm.

(2): Washing Treatment The agricultural film 100A is immersed in distilled water having a liquid temperature of 25° C., taken out from the distilled water, and dried.

(3): Sulfur fumigation treatment A vinyl house provided with a closed space having a substantially rectangular parallelepiped shape with a width of 50 cm, a width of 56 cm and a height of 60 cm is prepared. Next, a stirrer is installed on the top surface inside the vinyl house, a heating device is installed on the bottom surface inside the vinyl house, and an aluminum foil tray is placed on the heating device. The four test pieces A are placed in a suspended state inside a vinyl house.
Then, the next sulfur fumigation operation is repeated 4 times.

(Sulfur fumigation operation)
120 mg of powdery sulfur is put into the tray. Subsequently, the rotation speed of the stirrer is set to 180 rpm, and the tray is heated at 190° C. for 4 hours.

(4): Surface treatment Light irradiation is performed on the test piece A for 102 minutes under the following conditions, and then water is sprayed on the test piece A for 18 minutes together with light irradiation under the following conditions. The operation for 120 minutes in total is set as one cycle, and a total of 60 cycles are performed, and the surface treatment for a total of 120 hours is performed on the test piece A.

(Conditions of light irradiation)
The test piece A is irradiated with a xenon lamp having an irradiation intensity of 60 W/m ² under the conditions of a temperature of 65° C. and a relative humidity of 50%.

According to the knowledge of the present inventor, it was found that the measurement variation of the content of the elemental sulfur contained in the film can be reduced by performing an appropriate surface treatment after the fumigation of sulfur. The detailed mechanism is not clear, but it is considered that the sulfur adhering to the film surface can be appropriately removed by the surface treatment. Further, it has been found that not only light irradiation but also water spraying is an important factor for this surface treatment.

(5): Measurement of elemental sulfur content 200 mg of a sample obtained by cutting the test piece A in the plate thickness direction was added to 5 g of nitric acid to obtain a nitric acid solution. A measurement solution is obtained by subjecting this nitric acid solution to a pretreatment for liquefying the sample using a microwave wet decomposition method. The content of elemental sulfur in the obtained measurement solution is measured using an ICP emission spectrometer. The content of elemental sulfur in the measurement solution is defined as the content (ppm) of elemental sulfur in the agricultural film 100.

According to the knowledge of the present inventor, it has been found that a vinyl greenhouse used a plurality of times in the sulfur fumigation operation can reduce variations in the measurement of the sulfur element content by using a new greenhouse at an appropriate timing.

Hereinafter, the procedure B for measuring the light transmittance of the agricultural film 100 will be described.
<Procedure B>
Procedure B1: Using the agricultural film 100 to be measured in the above procedure A, the film is cut out to prepare a strip-shaped film test piece B having a length of 10 cm and a width of 5 cm. Next, the test piece B is pretreated by immersing the test piece B in liquid paraffin and holding the taken out test piece B in a suspended state for 30 minutes.

Procedure B2: The test piece B pretreated in the above procedure B1 is placed in a spectrophotometer, and the light transmittance (%) from a wavelength of 200 nm to 700 nm is measured. The obtained measured values are normalized so that the light transmittance at 400 nm is 85%. The light transmittance at the wavelength Xnm after normalization is represented by Tx (%).

The sulfur uptake measured according to the above procedure A is ΔW, the thickness of the agricultural film 100 is H1, and the thickness of the layer containing the hindered amine light stabilizer and the synergist (weather resistant layer 10) is H2.
At this time, the agricultural film 100 has (ΔW×(H2/H1))/H2 of 2.80 ppm/μm or more and 4.70 ppm/μm or less, preferably 2.81 ppm/μm or more and 4.60 ppm/μm or less, More preferably, it is configured to satisfy 2.82 ppm/μm or more and 4.50 ppm/μm or less.
Here, the film thickness ratio in the weather resistant layer 10 contained in the entire agricultural film 100 is calculated by H2/H1. The sulfur uptake amount per unit thickness in the weather resistant layer 10 is calculated by 1/H2.

By setting the upper limit of (ΔW×(H2/H1))/H2 to the upper limit or less, the long-term weather resistance can be improved. Specifically, even when the fumigation of sulfur or the application of sulfur is performed once or a plurality of times during the growing of the plant, it is possible to suppress the deterioration of the long-term weather resistance of the agricultural film 100.

On the other hand, by setting the value of (ΔW×(H2/H1))/H2 below the lower limit value, the transparency of the agricultural film 100 can be improved, and thus an agricultural film suitable for a greenhouse can be realized. It is also possible to improve long-term weather resistance.

Is measured according to the above procedure B, the light transmittance of the light transmittance _T 290, 340 nm of 290nm and _{T 340.}
At this time, the agricultural film 100 may satisfy T ₂₉₀ /T ₃₄₀ of 0.76 or more and 1.00 or less, preferably 0.80 or more and 1.00 or less, and more preferably 0.85 or more and 0.99 or less. Composed. Generally, the UV-B region of 280 nm to 315 nm is considered to be a wavelength region necessary for growth of crops, prevention of diseases, prevention of pest damage, and the like. Therefore, by setting T ₂₉₀ /T ₃₄₀ to the lower limit value or more, the plant growth ability of the agricultural film 100 can be enhanced.

The light transmittance T _{660 at 660} nm in the agricultural film 100 is, for example, 80% or more, preferably 85% or more, more preferably 86% or more. Therefore, the agricultural film 100 can have excellent light transmittance in a wide wavelength range.

In the present embodiment, for example, by appropriately selecting the type and blending amount of each component contained in the agricultural film, the method for preparing the agricultural film, and the like, the above (ΔW×(H2/H1))/H2, light rays It is possible to control the transmittance. Among these, for example, the kind and composition ratio of the hindered amine light stabilizer and the benzoate compound are appropriately selected, and the addition method thereof is the above (ΔW×(H2/H1))/H2, light transmission. It is mentioned as an element for making the rate into a desired numerical range.

The agricultural film 100 can be used for various purposes such as a material for forming various agricultural and horticultural equipment such as a greenhouse, a material for protecting soil, or a housing material for housing soil. Among these, it is preferable to use it for forming a greenhouse.

Next, the agricultural film-forming resin composition of the present embodiment, which is used to form the agricultural film 100, will be described.

The resin composition for forming an agricultural film (hereinafter, simply referred to as a resin composition) is a hindered amine-based light selected from at least one of the compound represented by the above chemical formula A1 and the compound represented by the following chemical formula A2. A stabilizer, a synergist containing one or more selected from the benzoate compounds represented by the above general formula (B), and the above-mentioned thermoplastic resin.

As the compounding ratio of the above components in the resin composition, for example, the compounding ratio in the light resistant layer described in the agricultural film may be adopted.

The resin composition may contain, in addition to the above components, other additives that are usually used in agricultural films, as long as the effects of the present invention are not impaired.

As other additives, for example, phenolic antioxidants, phosphorus antioxidants, sulfur antioxidants, other hindered amine compounds, nucleating agents, processability improvers, fillers, plasticizers, metal soaps, infrared rays. Examples include absorbents, antistatic agents, antifogging agents, antifog agents, and antifungal agents. These may be used alone or in combination of two or more.

Examples of the phenolic antioxidant include 2,6-di-tert-butyl-p-cresol, 2,6-diphenyl-4-octadecyloxyphenol, stearyl (3,5-di-tert-butyl-4-). Hydroxyphenyl)propionate, distearyl (3,5-di-tert-butyl-4-hydroxybenzyl)phosphonate, tridecyl-3,5-di-tert-butyl-4-hydroxybenzylthioacetate, thiodiethylenebis[(3,5 -Di-tert-butyl-4-hydroxyphenyl)propionate], 4,4'-thiobis(6-tert-butyl-m-cresol), 2-octylthio-4,6-di(3,5-di-tert-butyl) -4-Hydroxyphenoxy)-s-triazine, 2,2'-methylenebis(4-methyl-6-tert-butylphenol), bis[3,3-bis(4-hydroxy-3-tert-butylphenyl)butyric Acid]glycol ester, 4,4′-butylidene bis(2,6-ditertiary butylphenol), 4,4′-butylidene bis(6-tert-butyl-3-methylphenol), 2,2′-ethylidene bis(4 ,6-di-tert-butylphenol), 1,1,3-tris(2-methyl-4-hydroxy-5-tert-butylphenyl)butane, bis[2-tert-butyl-4-methyl-6-(2 -Hydroxy-3-tert-butyl-5-methylbenzyl)phenyl]terephthalate, 1,3,5-tris(2,6-dimethyl-3-hydroxy-4-tert-butylbenzyl)isocyanurate, 1,3,3. 5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)isocyanurate, 1,3,5-tris(3,5-di-tert-butyl-4-hydroxybenzyl)-2,4,6- Trimethylbenzene, 1,3,5-tris[(3,5-di-tert-butyl-4-hydroxyphenyl)propionyloxyethyl]isocyanurate, tetrakis[methylene-3-(3',5'-di-tert-butyl) -4′-hydroxyphenyl)propionate]methane, 2-tert-butyl-4-methyl-6-(2-acryloyloxy-3-tert-butyl-5-methylbenzyl)phenol, 3,9-bis[2- (3-tert-butyl-4-hydroxy-5-methylhydrocinnamoyloxy)-1,1-dimethylethyl]-2,4,8,10-tetraoxaspiro[5.5]undecane, triethylene glycol bis [Β-(3-tert-butyl-4-hydroxy-5-methylphenyl) Propionate], tocophenol and the like.

Examples of the phosphorus-based antioxidant include triphenyl phosphite, tris(2,4-ditert-butylphenyl)phosphite, tris(2,5-ditert-butylphenyl)phosphite, tris(nonylphenyl). ) Phosphite, tris(dinonylphenyl)phosphite, tris(mono-dimixed nonylphenyl)phosphite, diphenylacid phosphite, 2,2'-methylenebis(4,6-ditert-butylphenyl)octylphosphite , Diphenyldecylphosphite, diphenyloctylphosphite, di(nonylphenyl)pentaerythritol diphosphite, phenyldiisodecylphosphite, tributylphosphite, tris(2-ethylhexyl)phosphite, tridecylphosphite, trilaurylphosphite, Dibutyl acid phosphite, dilauryl acid phosphite, trilauryl trithiophosphite, bis(neopentyl glycol)-1,4-cyclohexanedimethyldiphosphite, bis(2,4-ditertiary butylphenyl) pentaerythritol diphosphite Fight, bis(2,5-di-tert-butylphenyl)pentaerythritol diphosphite, bis(2,6-di-tert-butyl-4-methylphenyl)pentaerythritol diphosphite, bis(2,4-dicumyl) Phenyl)pentaerythritol diphosphite, distearyl pentaerythritol diphosphite, tetra(C12-15 mixed alkyl)-4,4'-isopropylidene diphenylphosphite, bis[2,2'-methylenebis(4,6-dia) Milphenyl)]-isopropylidene diphenyl phosphite, tetratridecyl 4,4'-butylidene bis(2-tert-butyl-5-methylphenol) diphosphite, hexa(tridecyl)-1,1,3-tris(2- Methyl-5-tert-butyl-4-hydroxyphenyl)butane triphosphite, tetrakis(2,4-ditert-butylphenyl)biphenylene diphosphonite, tris(2-[(2,4,7,9-tetrakis Tert-Butyldibenzo[d,f][1,3,2]dioxaphosphepin-6-yl)oxy]ethyl)amine, 2-(1,1-dimethylethyl)-6-methyl-4-[ 3-[[2,4,8,10-Tetrakis(1,1-dimethylethyl)dibenzo[d,f][1,3,2]dioxaphosphepin-6-yl]oxy]propyl]fluoro Enol, 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide, 2-butyl-2-ethylpropanediol-2,4,6-tri-tert-butylphenol monophosphite and the like. To be

Examples of the sulfur-based antioxidants include dialkylthiodipropionates such as dilauryl, dimyristyl, myristyl stearyl, and distearyl esters of thiodipropionic acid, and polyols such as pentaerythritol tetra(β-dodecylmercaptopropionate). .Beta.-alkyl mercaptopropionic acid esters of.

Examples of the other hindered amine compound include 2,2,6,6-tetramethyl-4-piperidyl stearate, 1,2,2,6,6-pentamethyl-4-piperidyl stearate, 2,2,6. ,6-Tetramethyl-4-piperidyl benzoate, bis(2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis(1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, Tetrakis(2,2,6,6-tetramethyl-4-piperidylbutane tetracarboxylate, tetrakis(1,2,2,6,6-pentamethyl-4-piperidylbutane tetracarboxylate, bis(2,2,6 ,6-Tetramethyl-4-piperidyl)-di(tridecyl)-1,2,3,4-butanetetracarboxylate, bis(1,2,2,6,6-pentamethyl-4-piperidyl)-di( Tridecyl)-1,2,3,4-butanetetracarboxylate, bis(1,2,2,6,6-pentamethyl-4-piperidyl)-2-butyl-2-(3,5-di-tert-butyl) -4-hydroxybenzyl)malonate, 1-(2-hydroxyethyl)-2,2,6,6-tetramethyl-4-piperidinol/diethyl succinate polycondensate, 1,6-bis(2,2,6) ,6-Tetramethyl-4-piperidylamino)hexane/dibromoethane polycondensate, 1,6-bis(2,2,6,6-tetramethyl-4-piperidylamino)hexane/2,4-dichloro-6 -Morpholino-s-triazine polycondensate, 1,6-bis(2,2,6,6-tetramethyl-4-piperidylamino)hexane/2,4-dichloro-6-tertiaryoctylamino-s-triazine Polycondensate, 1,5,8,12-Tetrakis[2,4-bis(N-butyl-N-(2,2,6,6-tetramethyl-4-piperidyl)amino)-s-triazine-6 -Yl]-1,5,8,12-tetraazadodecane, 1,5,8,12-tetrakis[2,4-bis(N-butyl-N-(1,2,2,6,6-pentamethyl -4-Piperidyl)amino)-s-triazin-6-yl]-1,5,8,12-tetraazadodecane, 1,6,11-tris[2,4-bis(N-butyl-N-( 2,2,6,6-Tetramethyl-4-piperidyl)amino)-s-triazin-6-ylaminoundecane, 1,6(1,2,2,6,6-pentamethyl-4-piperidyl)amino) -S-triazine-6 And hindered amine compounds such as ylaminoundecane.

Examples of the nucleating agent include aromatic carboxylic acid metal salts such as aluminum p-t-butylbenzoate and sodium benzoate; sodium bis(2,4-ditert-butylphenyl)phosphate, bis(2,2 Acidic phosphoric acid ester metal salts such as lithium 4-di-tert-butylphenyl)phosphate, sodium-2,2'-methylenebis(4,6-di-tert-butylphenyl)phosphate; dibenzylidene sorbitol, bis(methylbenzylidene) Examples thereof include polyhydric alcohol derivatives such as sorbitol.

The processability improver can be appropriately selected from known processability improvers, and, for example, ethylenebisstearic acid amide or erucic acid amide may be used.

Examples of the filler include calcium carbonate, calcium oxide, calcium hydroxide, zinc hydroxide, zinc carbonate, zinc sulfide, magnesium oxide, magnesium hydroxide, magnesium carbonate, aluminum oxide, aluminum hydroxide, sodium alumina silicate, Hydrocalumite, aluminum silicate, magnesium silicate, calcium silicate, metal silicates such as zeolite, activated clay, talc, clay, red iron oxide, asbestos, antimony trioxide, silica, glass beads, mica, sericite, glass Flakes, asbestos, wollastonite, potassium titanate, PMF (mineral fiber), gypsum fiber, zonolite, MOS (Magnesium Hydroxide Sulfate Hydrate, fibrous magnesium compound), phosphate fiber, glass fiber, carbon fiber, aramid fiber, cellulose nano Fiber etc. are mentioned. Among these, an inorganic filler may be used. The filler is preferably surface-treated with a titanium-based or silane-based surface treatment agent in order to improve the affinity with the resin.

Examples of the plasticizer include phthalic acid ester, dibasic acid ester, chlorinated paraffin, polyester, epoxidized ester, phosphoric acid ester, trimellitic acid ester, and the like.

As the metal soap, for example, a salt of a metal such as magnesium, calcium, aluminum, or zinc with a saturated or unsaturated fatty acid such as lauric acid, myristic acid, palmitic acid, stearic acid, behenic acid, or oleic acid is used. .. Moisture content, melting point, particle size, composition of fatty acid, production method is metathesis method by reaction of alkali metal fatty acid salt and metal (hydr)oxide, or in presence or absence of solvent of fatty acid and metal (hydr)oxide It is used regardless of whether it is a direct method in which a neutralization reaction is performed below, or if an excess of either fatty acid or metal is used.

Examples of the infrared absorber include hydrotalcite compounds and lithium aluminum composite hydroxide. These may be used alone or in combination of two or more.
The hydrotalcite compound may be a natural product or a synthetic product, or may be a compound modified with an alkali metal such as lithium. _{Formula: ZnxMgyAl 2 (OH) 2 (} x + y + 2) CO 3 · nH 2 O ( wherein, x is 0 to 3, y is 1 to 6, also, x + y is a .n 0-10 showing the 4-6 The composition represented by (1) is preferable, and it can be used regardless of the presence or absence of crystal water or the presence or absence of surface treatment.
The hydrotalcite compound may be one obtained by dehydrating water of crystallization, a higher fatty acid such as stearic acid, a higher fatty acid metal salt such as an alkali metal salt of oleic acid, an organic sulfonic acid such as an alkali metal salt of dodecylbenzene sulfonic acid. It may be coated with a metal salt, higher fatty acid amide, higher fatty acid ester, wax or the like.

Examples of hydrotalcite compounds include, for example, natural hydrotalcite and trade names: DHT-4A (manufactured by Kyowa Chemical Industry Co., Ltd.), Magclear (manufactured by Toda Kogyo Co., Ltd.), Magceller (manufactured by Kyowa Chemical Industry Co., Ltd.), Stabiace HT-P (made by Sakai Chemical Industry Co., Ltd.) etc. are mentioned as an example of a lithium aluminum compound hydroxide, for example, OPTIMA-SS (made by Toda Kogyo Co., Ltd.), Mizucarak (made by Mizusawa Chemical Co., Ltd.). Etc.

Examples of the antistatic agent include cationic antistatic agents such as fatty acid quaternary ammonium ion salt and polyamine quaternary salt; higher alcohol phosphate ester salt, higher alcohol EO adduct, polyethylene glycol fatty acid ester, and anionic type Anionic antistatic agents such as alkyl sulfonates, higher alcohol sulfuric acid ester salts, higher alcohol ethylene oxide adduct sulfuric acid ester salts, and higher alcohol ethylene oxide adduct phosphoric acid ester salts; polyhydric alcohol fatty acid esters, polyglycol phosphoric acid esters, poly Nonionic antistatic agents such as oxyethylene alkyl allyl ether; amphoteric alkyl betaines such as alkyldimethylaminoacetic acid betaine; and amphoteric antistatic agents such as imidazoline type amphoteric active agents.

Examples of the antifogging agent include sorbitan monopalmitate, sorbitan monostearate, sorbitan monopalmitate, sorbitan monomontanate, sorbitan monooleate, sorbitan dioleate, and the like, and alkylene oxide adducts thereof. Sorbitan surfactant, glycerin monopalmitate, glycerin monostearate, diglycerin distearate, triglycerin monostearate, tetraglycerin dimontanate, glycerin monooleate, diglycerin monooleate, diglycerin sesquiole Glycerin fatty acid esters such as oleate, tetraglycerin monooleate, hexaglycerin monooleate, hexaglycerin trioleate, tetraglycerin trioleate, tetraglycerin monolaurate, hexaglycerin monolaurate and alkylene oxide adducts thereof Surfactants, polyethylene glycol-based surfactants such as polyethylene glycol monopalmitate, polyethylene glycol monostearate, alkylene oxide adducts of alkylphenols, esters of sorbitan/glycerin condensates with organic acids, polyoxyethylene (2 mol) Polyoxyethylene alkylamines such as stearylamine, polyoxyethylene (4 mol) stearylamine, polyoxyethylene (2 mol) stearylamine monostearate, polyoxyethylene (4 mol) laurylamine monostearate and fatty acid esters thereof Nonionic surfactants of

Examples of the above-mentioned antifoggant include a fluorine compound having a perfluoroalkyl group, an ω-hydrofluoroalkyl group and the like (especially a fluorine-containing surfactant), and a silicone compound having an alkylsiloxane group (especially a silicone-containing surfactant). ) And the like.

Examples of the antifungal agent include organic antifungal agents such as nitrogen-containing sulfur-containing agents, organic bromine-based agents, nitrogen-containing agents, and arsenic agents, and inorganic antifungal agents such as silver compounds.

The method for producing an agricultural film of this embodiment includes a molding step of molding the resin composition into a film.
A known method is used for the molding step, but a melt extrusion molding method such as an inflation method and a die method, a solution casting method, a calender method, a coextrusion method such as an inflation method and a die method, a multilayer processing method, a laminating method. Alternatively, an internal/external heating method or the like may be used. This gives a single or multiple layer agricultural film.

Further, the method for producing an agricultural film may further include a mixing step of mixing the above components to obtain a resin composition.
In the mixing step, after premixing using various mixers such as a tumbler and a Henschel mixer, a method of melt-kneading with a Banbury mixer, roll, Brabender, single-screw kneading extruder, twin-screw kneading extruder, kneader, etc. Can be mentioned.
Alternatively, the resin composition may be produced without premixing the respective components or premixing only some of the components and supplying the mixture to an extruder using a feeder and melt-kneading. Further, a resin composition obtained by mixing some components in advance and supplying them to an extruder and melt-kneading to form a masterbatch, and again mixing with other components and melt-kneading to produce a resin composition You can also do it.
Further, the synthetic resin used in the above-mentioned mixing/kneading step may have a predetermined shape such as powder, pellet, or the like, or a fibrous shape.

According to this embodiment, a method for improving the ability of an agricultural film to suppress sulfur absorption can be provided. The method for improving the sulfur absorption suppressing ability of the agricultural film can improve the sulfur absorption suppressing ability of the agricultural film 100 by adding a benzoate compound as a synergist to the hindered amine light stabilizer.

As the predetermined hindered amine light stabilizer and the predetermined benzoate compound, those described in the agricultural film are used.

According to this embodiment, a plant growing method using the agricultural film 100 can be provided. A method for growing a plant, a step of arranging the agricultural film 100 in the agricultural and horticultural equipment, a step of arranging the plant in the agricultural and horticultural equipment, and a step of fumigating sulfur in the agricultural and horticultural equipment, May be included. This makes it possible to realize agricultural and horticultural equipment with excellent long-term light resistance. For example, a greenhouse is used as the agricultural and horticultural equipment.

The embodiments of the present invention have been described above, but these are examples of the present invention, and various configurations other than the above can be adopted. Further, the present invention is not limited to the above-described embodiment, and modifications, improvements, etc. within the scope of achieving the object of the present invention are included in the present invention.
Hereinafter, an example of the reference mode will be additionally described.
1. A hindered amine light stabilizer selected from at least one of the compound represented by the chemical formula A1 and the compound represented by the chemical formula A2 below,
A synergist containing one or more selected from the benzoate compounds represented by the above general formula (B);
An agricultural film comprising a layer containing
(In the general formula (B), R ⁵ and R ⁶ are each independently an alkyl group having 1 to 8 carbon atoms, R ⁷ is an alkyl group having 1 to 30 carbon atoms, and an aryl group having 6 to 30 carbon atoms. Represents a group or an alkylaryl group having 7 to 30 carbon atoms.)
In the agricultural film,
When the sulfur uptake measured according to the following procedure A is ΔW, the thickness of the agricultural film is H1, and the thickness of the layer is H2, (ΔW×(H2/H1))/H2 is 2.80 ppm/ μm or more and 4.70 ppm/μm or less,
When the light transmittance of ₂₉₀ nm measured according to the following procedure B is T ₂₉₀ and the light transmittance of 340 nm is T ₃₄₀ , T ₂₉₀ /T ₃₄₀ is 0.76 or more and 1.00 or less,
Agricultural film.
<Procedure A>
Procedure A1: Using the agricultural film, according to the following order (1), (2), (4), and (5), the content of the elemental sulfur in the agricultural film before the sulfur fumigation treatment ( (ppm) is measured, and this measured value is designated as S ₀ .
Procedure A2: Using the agricultural film to be measured in Procedure A1, according to the following order of (1), (2), (3), (4), and (5), the sulfur fumigation treatment is performed. The content (ppm) of elemental sulfur in the agricultural film is measured, and this measured value is defined as S ₁ . However, S ₁ is an average value of four measured values.
Procedure A3: Using the S ₀ obtained in the above procedure A1 and the S ₁ obtained in the procedure A2, calculate the sulfur uptake amount (ppm) of the agricultural film based on the following formula (I). ..
|S ₁ -S ₀ | Equation (I)
(1): Preparation of test piece
The agricultural film is cut out to prepare a strip-shaped film test piece A having a length of 13 cm and a width of 2.5 cm.
(2): Washing process
The test piece A is immersed in distilled water having a liquid temperature of 25° C., taken out from the distilled water, and dried.
(3): Sulfur fumigation treatment
A vinyl house provided with a closed space having a substantially rectangular parallelepiped shape with a width of 50 cm, a width of 56 cm and a height of 60 cm is prepared. Subsequently, an agitator is installed on the top surface inside the vinyl house, a heating device is installed on the bottom surface inside the vinyl house, and an aluminum foil tray is placed on the heating device. The four test pieces A are installed in a suspended state inside the vinyl house.
Then, the next sulfur fumigation operation is repeated 4 times.
(Sulfur fumigation operation)
120 mg of powdery sulfur is put into the tray. Subsequently, the rotation speed of the stirrer is set to 180 rpm, and the tray is heated at 190° C. for 4 hours.
(4): Surface treatment
Light irradiation is performed on the test piece A for 102 minutes under the following conditions, and subsequently, water is sprayed on the test piece A for 18 minutes together with light irradiation under the following conditions. The operation for 120 minutes in total is set as one cycle, and 60 cycles are performed in total, and the surface treatment is performed on the test piece A for 120 hours in total.
(Conditions of light irradiation)
The test piece A is irradiated with a xenon lamp having an irradiation intensity of 60 W/m ² under the conditions of a temperature of 65° C. and a relative humidity of 50% .
(5): Measurement of sulfur element content
A 200 mg sample obtained by cutting the test piece A in the plate thickness direction is added to 5 g of nitric acid to obtain a nitric acid solution. This nitric acid solution is subjected to a pretreatment for liquefying the sample using a microwave wet decomposition method to obtain a measurement solution. The content of elemental sulfur in the obtained measurement solution is measured using an ICP emission spectrometer.
<Procedure B>
Procedure B1: Using the agricultural film to be measured in the above procedure A, the film is cut out to prepare a strip-shaped film test piece B having a length of 10 cm and a width of 5 cm. Subsequently, the test piece B is pretreated by immersing the test piece B in liquid paraffin and holding the taken out test piece B in a suspended state for 30 minutes.
Procedure B2: The test piece B pretreated in the above procedure B1 is placed in a spectrophotometer, and the light transmittance (%) from a wavelength of 200 nm to 700 nm is measured. The obtained measured values are normalized so that the light transmittance at 400 nm is 85%. The light transmittance at the wavelength Xnm after normalization is represented by Tx (%).
2. 1. An agricultural film as described in,
An agricultural film having a light transmittance T _{660 at 660} nm of 80% or more in the agricultural film, measured according to the above procedure B.
3. 1. Or 2. An agricultural film as described in,
An agricultural film, wherein the benzoate compound comprises the compound B1 or the compound B2 described above.
4. 1. ~3. An agricultural film as described in any one of,
When the content of the hindered amine light stabilizer in the layer is A and the content of the synergist is B, A and B are 0.2/0.8≦A/B≦0.95/ Meets 0.05,
Agricultural film.
5. 1. ~4. An agricultural film as described in any one of,
An agricultural film, wherein the layer comprises a thermoplastic resin.
6. 5. An agricultural film as described in,
An agricultural film in which the thermoplastic resin contains linear low-density polyethylene or low-density polyethylene.
7. 5. Or 6. An agricultural film as described in,
The agricultural film, wherein the content of the hindered amine light stabilizer and the synergist in the layer is 0.01 parts by mass or more and 10 parts by mass or less based on 100 parts by mass of the thermoplastic resin.
8. 1. ~ 7. An agricultural film as described in any one of,
Agricultural film used to form greenhouses.
9. 1. ~8. A resin composition for forming an agricultural film, which is used for forming the agricultural film according to any one of 1.
10. A method for improving the sulfur absorption suppressing ability of an agricultural film, which comprises adding a benzoate compound as a synergist to a hindered amine light stabilizer to improve the sulfur absorption suppressing ability of the agricultural film.
11. In the green house, 1. ~8. A step of disposing the agricultural film according to any one of,
Arranging plants in the greenhouse,
A step of fumigating sulfur in the greenhouse,
How to grow plants.

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

<Preparation of resin composition>
(Test Example 1)
100 parts by weight of a thermoplastic resin (linear low-density polyethylene), 0.2 part by weight of a hindered amine light stabilizer represented by the following chemical formula A1, and a benzoate compound 0.8 represented by the following chemical formula B1 as a synergist. Parts by mass, phenolic antioxidant (stearyl(3,5-di-tert-butyl-4-hydroxyphenyl)propionate) 0.05 parts by mass, phosphorus-based antioxidant (tris(2,4-di-tert-butylphenyl) ) Phosphite) 0.05 parts by mass and metal soap (calcium stearate) 0.05 parts by mass are mixed for 30 minutes using a rocking mixer (manufactured by Aichi Electric Co., Ltd.), and then twin-screw extruder (Nikko TPK Shoji). Granules were produced under the conditions of an extrusion temperature of 190° C. and a screw rotation speed of 150 rpm using TEX-28V manufactured by Co., Ltd. The granulated pellets were dried at 60° C. for 8 hours using a hot air dryer (WINDY OVEN WFO-1001SD, manufactured by EYELA). Through the above steps, a pellet-shaped resin composition was obtained.

(Test Examples 2 to 14)
According to the compounding ratio shown in Table 1, a thermoplastic resin, a hindered amine light stabilizer and a benzoate compound were used, and otherwise, in the same manner as in Test Example 1, a pelletized resin composition was obtained by mixing and extrusion.

The compound A1 was used after being crushed in a mortar and allowed to stand overnight in a desiccator. Compound A2 was added using a liquid addition device.

The raw material information in Table 1 is shown below.
(Thermoplastic resin)
- linear low density polyethylene (Nippon Polyethylene Co., Ltd. NF464N, Density: 0.918kg ^{/ m} 3)
And low-density polyethylene (NUC Co., Ltd. NUC-8230, Density: 0.928kg ^{/ m} 3)
Ethylene - vinyl acetate copolymer resin (manufactured by Tosoh Corporation Ultrathene 630, density: 0.936kg ^{/ m} 3)

(Hindered amine light stabilizer)

(Benzoate compound)

<Production of agricultural film>
Using the resin composition in pellet form obtained in Test Examples 1 to 14, using an inflation molding machine, resin temperature: 190° C., torque: 50 to 70 N·m, extrusion rate: 1.5 kg/h Extrusion was performed under the conditions to prepare single-layer agricultural films 1 to 14 having a thickness of 50 μm. At this time, the thickness H1 of the agricultural film was 50 μm, and the thickness H2 of the layer containing the hindered amine light stabilizer and the synergist was 50 μm. The thickness was measured using a digital microscope on a cut surface obtained by cutting the agricultural film in the plate thickness direction.
Here, the detailed production conditions of the agricultural film are as follows.
A ring die having a diameter of 25 mm and a slit width of 0.8 mm was put into a LABO PLASTOMILL 4C150-01 manufactured by Toyo Seiki Co., Ltd., which has a pellet of φ20 mm and L/D=25 (full flight screw CR=2.0). The film obtained by film formation by the inflation molding used was wound up by a film take-up device manufactured by SUMAK. The conditions of the extrusion section were a processing temperature of 190° C. and a screw rotation speed of 60 rpm, and the winding speed was adjusted so that the film for agriculture had a thickness of 50 μm.

About the obtained agricultural film, the amount of sulfur uptake and the light transmittance were measured according to the following procedures.

<Measurement of sulfur uptake amount>
(Procedure A1)
Using the obtained agricultural film, according to the following order of (1), (2), (4), and (5), the content of the elemental sulfur (ppm) in the agricultural film before the sulfur fumigation treatment Was measured. This measured value is S ₀ .
(Procedure A2)
According to the order of (1), (2), (3), (4), and (5) below, using the agricultural film for which the content of elemental sulfur before the sulfur fumigation treatment is measured in step A1. The content (ppm) of elemental sulfur in the agricultural film after the sulfur fumigation treatment was measured. This measured value is S ₁ . However, S ₁ was an average value of four measured values.
(Procedure A3)
Then, the sulfur uptake amount ΔW (ppm) of the agricultural film was calculated based on the following formula (I) using S ₀ obtained in the above procedure A1 and S ₁ obtained in the procedure A2.
ΔW (ppm)=|S ₁ −S ₀ |...Equation (I)

(1): Preparation of test piece An agricultural film was cut out to prepare a strip-shaped film test piece A having a length of 13 cm and a width of 2.5 cm.

(2): Washing Treatment Test piece A, liquid temperature 25°C, 3 L of distilled water, and a stirrer chip were put into a beaker having a diameter of 18 cm, and stirred with a stirrer for 5 minutes. The test piece A immersed in distilled water was taken out, and the moisture on the surface thereof was wiped off with Kimwipe. Then, the test piece A was dried by holding it in a suspended state for 30 minutes.

(3): Sulfur Fumigation Treatment FIG. 2 shows an outline of the fumigation equipment 200 used for the sulfur fumigation treatment.
First, a vinyl house 210 (manufactured by AS ONE, portable fume hood econo hood) having a closed space of 50 cm in length×56 cm in width×60 cm in height and having a substantially rectangular parallelepiped shape was prepared.
Subsequently, a stirrer 220 (manufactured by Shinto Kagaku Co., Ltd., Three One Motor BL1200) was installed on the top surface 212 inside the vinyl house 210, and a heating device (hot plate 230) was installed on the bottom surface 214 inside thereof. Then, a tray 240 (bottom area: 16 cm ² , width: 4 cm, depth: 4 cm, height: 2 cm) made of aluminum foil was arranged in the center on the hot plate 230 (C-mag hot plate HP4 made by IKA). On the other hand, four test pieces A (test piece 250) were placed in a suspended state inside the vinyl house 210. The four test pieces 250 were arranged so as to be appropriately separated from each other and to be positioned at about half the height of the greenhouse 210.
Then, the following sulfur fumigation operation was repeated 4 times.
(Sulfur fumigation operation)
First, 120 mg of powdery sulfur 260 was put into the tray 250. Subsequently, the stirrer 220 was rotated at a rotation speed of 180 rpm, and in that state, the tray 240 was heated at 190° C. for 4 hours using the hot plate 230. At this time, the hot plate 230 was heated from 20° C. to 190° C. in about 4 minutes. After that, the hot plate 230 was stopped to end the heating, and naturally cooled to room temperature over about 30 minutes.

(4): Surface treatment Light irradiation was performed on the test piece A for 102 minutes under the following conditions, and subsequently, water was sprayed on the test piece A for 18 minutes together with light irradiation under the following conditions. The operation for 120 minutes in total was set as one cycle, and 60 cycles were performed in total, and the surface treatment for 120 hours was performed on the test piece A in total.
(Conditions of light irradiation)
For the test piece A, a xenon lamp having a UV irradiation intensity of 60 W/m ² and a wavelength of 300 to 400 nm under a condition of using a xenon weather resistance tester, a black panel temperature of 65° C., a relative humidity of 50%, and a borosilicate filter. Was irradiated for 120 hours.

(5): Measurement of elemental sulfur content 200 mg of a sample obtained by cutting the test piece A in the plate thickness direction was added to 5 g of nitric acid to obtain a nitric acid solution. A microwave wet decomposition apparatus (Analytik jena, TOPwave) is used for this nitric acid solution to perform a pretreatment for liquefying the sample under the conditions of a temperature of 230° C. and a pressure of 40 Bar for 1 hour. A measurement solution was obtained.
The content of elemental sulfur in the obtained measurement solution was measured using an ICP emission spectrometer (SII3Nano Technology, SPS3500).

<Measurement of light transmittance>
FIG. 3 is a diagram illustrating a procedure of pretreatment of a test piece whose light transmittance is to be measured. FIG. 4 shows an outline of the spectrophotometer for measuring the transmittance of the test piece.

(Preprocessing)
First, using the agricultural film to be measured in the above <Measurement of Sulfur Uptake Amount>, the film was cut out to prepare a strip-shaped film test piece B (test piece 310) having a length of 10 cm and a width of 5 cm. (FIG. 3(a)).
Then, the test piece 310 was immersed in liquid paraffin 320 (manufactured by FUJIFILM Wako Pure Chemical Industries, Ltd.) (FIG. 3(b)).
Then, it was taken out from the liquid paraffin 320, and the test piece 310 was held for 30 minutes in a state of being suspended in the atmosphere (FIG. 3C).

(Measurement procedure)
The pretreated test piece 310 was installed in the spectrophotometer 300 (UV-visible near-infrared spectrophotometer V-750 manufactured by JASCO Corporation) shown in FIG. The spectrophotometer 300 includes a light source 330 and a detector 340.
In the spectrophotometer 300, between the light source 330 and the detector 340, the entrance opening 370 provided in the first slit is installed in the first slit on the side opposite to the light source 330 so as to cover the entrance opening 370. The test piece 310, the empty cell holder 350, and the outlet opening 380 provided in the second slit are arranged.
The light ray 360 emitted from the light source 330 passes through the entrance aperture 370, the test piece 310, the empty cell holder 350, and the exit aperture 380 to reach the detector 340.
The light transmittance (%) of the test piece 310 at each wavelength when the wavelength of the light ray 360 was varied from 200 nm to 700 nm was measured using the spectrophotometer 300 of FIG.
After that, the obtained measured values were normalized so that the light transmittance at 400 nm was 85%.
Table 1 shows the values of Tx when the light transmittance at the wavelength Xnm after normalization is Tx (%).

(Examples 1 to 12, Comparative Examples 1 and 2)
Based on the measurement results of the above sulfur uptake amount and light transmittance, the obtained agricultural films 1 to 14 were used as the agricultural films of Examples 1 to 12 in Table 2, and the obtained agricultural films 13 were used. , 14 were used as the agricultural films of Comparative Examples 1 and 2 in Table 2.

The agricultural films of Examples and Comparative Examples were evaluated based on the following evaluation items. The results are shown in Table 2.

(Long-term weather resistance)
Regarding the agricultural films of Examples and Comparative Examples, the UV irradiation intensity was 60 W/m ² and the wavelength was 300 according to ISO 4892-2 under the conditions of a black panel temperature of 65° C., a relative humidity of 50% and a borosilicate filter. A weather resistance accelerated test was conducted by irradiating a xenon lamp of 400 nm for 120 hours. At this time, 120 minutes was defined as 1 cycle, and during the irradiation time of 1 cycle, water was sprayed for 102 minutes and light was sprayed for 18 minutes, and water was sprayed for 60 cycles of 120 hours in total.
During this weathering accelerating test, every 120 hours, (Sulfur fumigation operation) was performed once in the same manner as the above (3): Sulfur fumigation treatment.
Then, at 0 h, 840 h, 1200 h, and 2040 h of the weathering accelerating test, the tensile strength residual ratio of each film was measured at a test speed of 500 mm/min using AG-Xplus manufactured by Shimadzu Corporation according to JIS K7161-1. %) was measured. The tensile strength residual rate (%) was defined as the reduction rate of the tensile strength when the tensile strength of the film before the weathering accelerated test was 100%.
As a result, at 1200 h, the tensile strength residual ratio of Comparative Example 1 showed a smaller value than that of Examples 1 to 12 and Comparative Example 2, and at 2040 h, the tensile strength residual ratio of Comparative Example 1 and Comparative Example 2 was obtained. However, the value was lower than those of Examples 1 to 12. Therefore, it was shown that the agricultural films of Examples 1 to 12 were superior in long-term weather resistance to Comparative Examples 1 and 2.

(transparency)
Haze (haze value: %) was measured according to JIS K7136 about the agricultural films of Examples and Comparative Examples. The haze values of the agricultural films 1 to 12 of Examples 1 to 12 were low enough to be practically usable. On the other hand, the haze value of the agricultural film 14 of Comparative Example 2 was significantly higher than that of each Example (Table 1).
The surface of the agricultural films of Examples 1 to 12 and Comparative Example 2 was observed. As a result, no bloom was observed on the surface of Examples 1 to 12, but bloom was observed on the surface of Comparative Example 2.
Therefore, in the agricultural film 14 of Comparative Example 2, it is speculated that the haze value was increased by the bloom from the layer containing the hindered amine light stabilizer and the synergist.

(Comparative example 3)
100 parts by mass of a thermoplastic resin (linear low-density polyethylene), 0.4 parts by mass of a hindered amine light stabilizer represented by the chemical formula A1, 0.1 part by mass of a benzoate compound represented by the chemical formula B1, and ultraviolet light. Absorber (triazine UV absorber, 2,4-bis(2,4-dimethylphenyl)-6-(2-hydroxy-4-n-octyloxyphenyl)-1,3,5-triazine, Cytec Industry Co., Ltd. Manufactured by Siasorb UV1164) was mixed with a rocking mixer (manufactured by Aichi Electric Co., Ltd.) for 30 minutes, and then a twin-screw extruder (manufactured by Nikko TPK Trading Co., Ltd., TEX-28V) was used. Granulation was performed under the conditions of an extrusion temperature of 190° C. and a screw rotation speed of 150 rpm. The granulated pellets were dried at 60° C. for 8 hours using a hot air dryer (WINDY OVEN WFO-1001SD, manufactured by EYELA). Through the above steps, a pellet-shaped resin composition was obtained.
Using the obtained pellet-shaped resin composition, an agricultural film 15 having a thickness of 50 μm was produced in the same manner as in <Production of agricultural film> above.
Regarding the agricultural film 15, the light transmittance at wavelengths from 200 nm to 700 nm was measured in the same manner as the above (light transmittance). The obtained measured values were normalized so that the light transmittance at 400 nm was 85%.
As a result, in the agricultural film 15, the light transmittance of ₂₉₀ nm was T ₂₉₀ : 53.1%, the light transmittance of ₃₄₀ nm was T ₃₄₀ : 71.2%, and the light transmittance was T ₂₉₀ /T ₃₄₀ : 0.75.

It was shown that the agricultural films of Examples 1 to 12 were excellent in long-term weather resistance as compared with Comparative Example 1 and excellent in transparency as compared with Comparative Example 2. Such an agricultural film is suitable as a member used for growing agricultural products and plants, and can be used particularly as a material for greenhouses.
Moreover, the sulfur absorption suppressing ability of the agricultural film can be improved by appropriately blending the hindered amine light stabilizer and the benzoate compound. Therefore, the agricultural film of the examples can be suitably used for sulfur fumigation/sulfur spraying and the like performed when growing plants and agricultural products.

10 Weatherproof layer 20 Base layer 100 Agricultural film 200 Fumigation equipment 210 Vinyl house 212 Top surface 214 Bottom surface 220 Stirrer 230 Hot plate 240 Tray 250 Test piece 250 Tray 260 Sulfur 300 Spectrophotometer 310 Test piece 320 Liquid paraffin 330 Light source 340 Detector 350 Cell Holder 360 Light Ray 370 Entrance Aperture 380 Exit Aperture

Claims (4)

To the hindered amine light stabilizer, by adding a benzoate compound as its synergist, to improve the sulfur absorption suppressing ability in the agricultural film, a method of improving the sulfur absorption suppressing ability of the agricultural film ,
The hindered amine light stabilizer contains at least one of a compound represented by the following chemical formula A1 and a compound represented by the following chemical formula A2,
The synergist contains one or more selected from benzoate compounds represented by the following general formula (B):
When the mass-converted addition amount of the hindered amine light stabilizer is A and the synergist mass-added amount is B, A and B are 0.2/0.8≦A/B≦0. Meets 95/0.05,
A method for improving the ability of an agricultural film to suppress sulfur absorption .

(In the general formula (B), R5 and R6 are each independently an alkyl group having 1 to 8 carbon atoms, R7 is an alkyl group having 1 to 30 carbon atoms, an aryl group having 6 to 30 carbon atoms, or Represents an alkylaryl group having 7 to 30 carbon atoms.) The method for improving the sulfur absorption suppressing ability of an agricultural film according to claim 1, wherein the synergist contains at least one of a compound represented by the following chemical formula B1 and a compound represented by the following chemical formula B2.

The method for improving the sulfur absorption suppressing ability of an agricultural film according to claim 1 or 2 , comprising a step of incorporating the hindered amine light stabilizer and a benzoate compound into a layer in the agricultural film. The agricultural use according to any one of claims 1 to 3, including a step of obtaining a raw material composition that constitutes a layer in the agricultural film by mixing the hindered amine light stabilizer and a benzoate compound. A method for improving the ability of a film to suppress sulfur absorption.

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