JP2002360084A - Polyolefin-based resin film for agricultural use - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a film for agricultural use, excellent in heat retaining properties, having no reduction in weatherability caused by agrochemicals and easily treated to be disposed. SOLUTION: This polyolefin-based resin film for agricultural use is prepared by blending a polyolefin-based resin with a hydrotalcite compound heat treated at 200-300 deg.C and expressed by formula (1) and a hindered amine-based compound. [M<2+> 1-x M<3+> x (OH)2 ]x+ [A<n-> x/n mH2 O]<x-> (1) (wherein M<2+> expresses a divalent metal ion; M<3+> expresses a trivalent metal ion; A<n-> expresses a n-valent anion; x is a number in the range expressed by 0<x<=0.5; m is a number in the range expressed by 0<=m<=5).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to an agricultural film used for an agricultural house or the like. More specifically, the present invention relates to a polyolefin resin film for agriculture, which has excellent heat retention and does not decrease weather resistance due to pesticides.

[0002]

2. Description of the Related Art Until now, polyvinyl chloride films have been the mainstream for agricultural films used in agricultural houses, tunnels, and the like.
There was a problem that the plasticizer bleed out to the surface of the film during the spreading caused dirt to adhere to it, lowering the total light transmittance, and furthermore, there was a problem that it was difficult to dispose because incineration after use generates harmful gases. . Therefore, in recent years, films made of polyolefin resins such as polyethylene and ethylene-vinyl acetate copolymer have been increasingly used instead of polyvinyl chloride films.

[0003] Agricultural films are required to have various performances. Among them, weather resistance and heat retention are important performances. Generally, improvement of weather resistance is performed by adding various weather agents to a synthetic resin used for agricultural films, and improvement of heat retention is performed by adding a heat insulator such as an inorganic filler.

At present, the mainstream of the weathering agent is a hindered amine compound having a large improvement effect in a small amount. However, even in an agricultural film using a hindered amine compound, an extreme decrease in weather resistance is sometimes observed, and various pesticides used during crop cultivation are listed as the causative substances. A hindered amine compound originally has a property of strongly reacting with an acidic compound. Generally used pesticides are organic sulfur-based, organic chlorine-based, and organic phosphorus-based compounds that are acidic in nature or produce acidic substances such as sulfuric acid, hydrochloric acid, and phosphoric acid in the process of decomposition. There are many. For this reason, it is considered that the hindered amine compound is deteriorated by reacting with the pesticide itself or an acidic substance generated in a decomposition process, and its performance as a weathering agent is greatly reduced.

[0005] In addition, a heat insulating agent is used in agricultural films in order to suppress a temperature drop in the house at night or the like. Inorganic fillers that absorb infrared rays are generally used as heat insulating agents. This is because the inorganic filler contained in the agricultural film absorbs the infrared rays radiated from the ground that absorbed the solar energy during the day, thereby suppressing the energy radiated from the ground from being dissipated to the outside,
This is to maintain the temperature inside the house higher than outside.

[0006] Regarding the improvement of heat retention, see Japanese Patent Application Laid-Open No. 63-1 / 1988.
No. 49148 discloses an agricultural film to which a hydrotalcite compound is added. For improvement of weather resistance, Japanese Patent Application Laid-Open No. 63-175072 discloses an agricultural film in which a hydrotalcite compound and a hindered amine compound are added. Films are disclosed, but in each case, in order to obtain a sufficient improvement effect, it is necessary to add a large amount of these additives, resulting in a decrease in physical properties of the film and a decrease in total light transmittance. And a problem of cost increase.

[0007]

SUMMARY OF THE INVENTION An object of the present invention is to provide an agricultural film which is excellent in heat retention, does not deteriorate in weather resistance due to pesticides, and can be easily disposed of.

[0008]

Means for Solving the Problems As a result of intensive studies, the present inventors have found that a polyolefin resin has a content of 200 to 300.
The present inventors have found that an agricultural polyolefin-based resin film obtained by mixing a hydrotalcite-based compound and a hindered amine-based compound heat-treated at ℃ can solve this problem, and completed the present invention based on the finding.

That is, the present invention comprises the following. (1) An agricultural polyolefin-based resin film comprising a polyolefin-based resin and a hydrotalcite-based compound represented by the following formula 1 and a hindered amine-based compound, which are heat-treated at 200 to 300 ° C .: ( ^Wherein , M ²⁺ represents a divalent metal ion, M ³⁺ represents a trivalent metal ion, ^{An −} represents an n-valent anion, and x represents 0 <
A number in the range of x ≦ 0.5 and m indicates a number in the range of 0 ≦ m ≦ 5. )

(2) Of the hydrotalcite compounds, 2
Valent metal ion (M ²⁺ ) is ^replaced by magnesium ion (Mg
²⁺ ), the trivalent metal ion (M ³⁺ ) is an aluminum ion (Al ³⁺ ), and the n-valent anion (A
wherein (1) agricultural polyolefin resin film, wherein the ^n-) is carbonate ion _(CO ^{3 2-).}

(3) In a low-density polyethylene film having a thickness of 100 μm containing 7.5% by weight of the hydrotalcite compound, the average transmittance of infrared light having a wavelength of 6.3 to 6.6 μm is obtained. Value is 1
(1) wherein the average value of the infrared transmittance at a wavelength of 14 to 25 μm is 5 to 15%.
Alternatively, the agricultural polyolefin resin film according to (2).

[0012]

Embodiments of the present invention will be described below. The agricultural polyolefin resin film of the present invention is obtained by blending a hydrotalcite compound and a hindered amine compound heat-treated at 200 to 300 ° C. with a polyolefin resin.

The polyolefin resin used in the agricultural polyolefin resin film of the present invention is ethylene,
Propylene, 1-butene, 1-pentene, 4-methyl-
1-pentene, 1-hexene, 1-octene and other α-olefin crystalline homopolymers, these two or more α-olefin crystalline, low-crystalline or amorphous copolymers,
Copolymers of the above-mentioned α-olefins and vinyl acetate are mentioned, and these resins may be used alone or in combination of two or more. Either a polyolefin resin polymerized with a multisite catalyst such as a Ziegler catalyst or a polyolefin resin polymerized with a single site catalyst such as a metallocene catalyst may be used.

The polyolefin resin used for the agricultural polyolefin resin film of the present invention includes 200 to
A hydrotalcite compound represented by the following formula 1, which has been heat-treated at 300 ° C., preferably 250 to 300 ° C. for 1 to 3 hours, is added. ( ^Wherein , M ²⁺ represents a divalent metal ion, M ³⁺ represents a trivalent metal ion, ^{An −} represents an n-valent anion, and x represents 0 <
A number in the range of x ≦ 0.5 and m indicates a number in the range of 0 ≦ m ≦ 5. ) The heat treatment temperature of the hydrotalcite compound needs to be 200 to 300 ° C. 2
If the temperature is lower than 00 ° C., the effect of absorbing infrared rays and the effect of preventing the deterioration of weather resistance due to pesticides are insufficient. May not be obtained.

In the above hydrotalcite compound,
A divalent metal ion (M ²⁺ ) is a magnesium ion (M
g ²⁺ ), and when the trivalent metal (M ³⁺ ) is aluminum ion (Al ³⁺ ), the resulting polyolefin-based resin film has particularly good transparency and heat retention, which is preferable. Further, the n-valent anion (A ⁿ⁻ ) is a carbonate ion (C
If it is O 3 ^_2-), when manufacturing the polyolefin resin film, hardly causes corrosion of such processing equipment preferred.

The polyolefin-based resin film blended with the hydrotalcite compound heat-treated at 200 to 300 ° C. is compared with the conventional polyolefin-based resin film blended with the hydrotalcite compound only dried at about 110 ° C. Therefore, the infrared transmittances at the wavelength of 6.3 to 6.6 μm and the wavelength of 14 to 25 μm tend to decrease. In the present invention, particularly, in a low-density polyethylene film having a thickness of 100 μm and containing 7.5% by weight of the hydrotalcite compound, a wavelength of 6.3 to 6.6 is used.
μm infrared transmittance average value is 15 to 25%, wavelength is 14 to
Hydrotalcite compounds having an average infrared transmittance of 25 μm of 5 to 15% are preferably used.

The average particle size of the hydrotalcite compound is not particularly limited, but is preferably 0.5 to 5.0 μm. When the average particle size is 0.5 to 5.0 μm, there is little dust, so that it is easy to handle, and since there is no unevenness of the film surface due to coarse particles, water droplets are generated when the film is spread on the house or dust adheres, and There is no decrease in light transmittance, and there is little adverse effect on crops due to dropping.

In the present invention, the rate of addition of the hydrotalcite compound in the polyolefin resin is not particularly limited, but may be 0.5 to 0.5 based on the weight of the film.
It is desirably 15% by weight, preferably 1 to 10% by weight. When the addition rate is 0.5 to 15% by weight, the effect of improving the weather resistance of the film is sufficient, and there is no possibility that the physical properties and transparency are reduced.

In the present invention, as the hindered amine compound to be added to the polyolefin resin, those usually used as a weathering agent for the polyolefin resin are used. 6,
Molecular weight 2 consisting of 6-tetraalkylpiperidine derivative
More than 50 compounds are preferred. Specifically, the following equation 2
Compounds represented by the following chemical formulas can be exemplified. These compounds may be used alone or in combination of two or more.

[0020]

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[0021]

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[0022]

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[0023]

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[0024]

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[0025]

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[0026]

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[0027]

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[0028]

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In the present invention, the addition ratio of the hindered amine compound in the polyolefin resin is not particularly limited, but may be 0.01 to 0.01 based on the weight of the film.
It is preferred that it is blended in the range of 2% by weight. When the addition ratio is 0.01 to 2% by weight, the effect of improving the weather resistance of the film is sufficient, and there is no decrease in the transparency of the film due to the blooming phenomenon.

In the present invention, an elastic copolymer such as an ethylene-α-olefin copolymer or a diene copolymer may be added to the polyolefin resin for the purpose of improving flexibility. If necessary, heat insulator, anti-fog agent, anti-fog agent, heat stabilizer, antioxidant, weathering agent, ultraviolet absorber,
Various additives such as a slip agent, an anti-blocking agent, an antistatic agent and a pigment may be added.

The agricultural polyolefin resin film of the present invention is a polyolefin resin obtained by adding a hydrotalcite compound, a hindered amine compound, and, if necessary, an elastic copolymer or various additives to the polyolefin resin. The resin composition is subjected to inflation or T
It can be manufactured by forming a film by a known technique such as a die method. Corona discharge treatment may be performed after the production to improve the effect of exhibiting anti-fogging properties. Apply dustproof coating agent, etc.
After drying, a coating film may be formed on the surface.

The thickness of the agricultural polyolefin resin film of the present invention varies depending on the place where it is used, the required service life and the like, but generally about 0.05 to 0.3 mm is preferably used. The agricultural polyolefin-based resin film of the present invention may be a single-layer film, for example, 3
A multilayer film having a seed three-layer structure may be used.

[0033]

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

The polyolefin resins used in the examples and comparative examples and the evaluation methods of the obtained films are as follows. Melt flow rate (MFR) 190 ° C., 21.18 N according to JIS K 7210
It measured on condition of.

The density was measured according to JIS K 7112.

Optical Characteristics Using an SM color computer manufactured by Suga Test Instruments Co., Ltd.
The diffuse transmittance and the total light transmittance of the entire film were measured in accordance with IS K 7105. The higher the diffuse transmittance, the lower the transparency of the film, and the higher the total light transmittance, the better the film transmits sunlight.

Infrared Reflection Absorption Infrared Spectrometer (PERKIN ELMER PARAG)
The infrared transmittance of the covering material at a wave number region of 400～4000Cm ^-1 at ON1000PC) was measured every 10 cm ^-1, was calculated by integrating the black body radiation energy absorption amount for each wavenumber. The higher the infrared reflectance and absorptivity, the more difficult it is to transmit infrared rays radiated from the ground, indicating that the heat retention is excellent.

Average value of infrared transmittance Low density polyethylene (MFR = 1.7 g / 10 min, density
= 0.92 g / cm ³ ) and a composition prepared by adding and mixing 7.5% by weight of a hydrotalcite compound or other inorganic filler to a T-die film forming equipment equipped with a 20 mmφ extruder. Then, a film sample having a thickness of 100 μm was prepared. This film is transferred to an infrared spectrometer (P
ERKIN ELMER PARAGON1000P
C) at a wave number of 400 to 4000 cm ^-1 (wavelength of 2.5 to 2)
The infrared transmittance in the region of 5 μm) was measured, and the wavelength was 6.
Infrared average transmittance T ₁ at 3 to 6.6 μm and wavelength 14
It was calculated infrared average transmittance _{T 2} of the in ～25Myuemu.

Weather resistance A test film was placed on a mini-house (1.8 mx 0.9 m), and 100 ml of the following three representative pesticide diluents were sprayed twice a month onto the inner surface of the film house. Sprayed. The breaking load and breaking elongation were measured 6 months and 1 year after the start of spraying. The smaller the decrease in breaking load and breaking elongation with time, the better the weather resistance. 1. TPN (organic chlorine) diluent: 1 g of the drug substance in 100
Dilute with 0cc. 2. MEP (organic phosphorus-based) diluent: 1 g of the drug substance in 500
Dilute with cc. 3. Lime-sulfur mixture (organic sulfur-based) diluent: Dilute 1 cc of the bulk with 10 cc of water.

Examples 1 to 9 and Comparative Examples 1 to 7 Using an extruder for three types of three-layer blown film having one extruder of 65 mmφ and two extruders of 45 mmφ,
Molding temperature 170 ° C, blow ratio 2.5, thickness 0.1m
m was formed into a single-layer or multilayer film. Tables 1 and 2 show composition examples and evaluation results of each film.

The abbreviations and contents of the base resins in the examples of compounding each film shown in Tables 1 and 2 are as follows. LDPE: low density polyethylene, MFR = 0.8 g /
10 minutes, density = 0.92 g / cm ³ .MPE + LDPE: metallocene PE (MFR = 2.
0 g / 10 min, density = 0.91 g / cm ³ ) and the LD
An 8: 2 (weight ratio) mixture of PE. EVA (VA = 15 wt%): vinyl acetate content 15
Wt% ethylene vinyl acetate copolymer, MFR = 1.0
g / 10 min, density = 0.94 g / cm ³ . EVA (VA = 5 wt%): an ethylene vinyl acetate copolymer having a vinyl acetate content of 5% by weight, MFR = 1.5 g /
10 minutes, density = 0.93 g / cm ³ .

The abbreviations and contents of the inorganic fillers such as hydrotalcite compounds in the examples of blending the films shown in Tables 1 and 2 are as follows. DHT4A-2: Hydrotalcite compounds (Mg
—Al complex hydroxide salt (carbonate ion type, manufactured by Kyowa Chemical Industry Co., Ltd.), heat treatment temperature 280 ° C., heat treatment time 1.
5 hours, infrared average transmittance T ₁ 21%; T ₂ 11%. DHT4A: Hydrotalcite compounds (Mg-A
1. Complex hydroxide salt (carbonate ion type, manufactured by Kyowa Chemical Industry Co., Ltd.), heat treatment temperature 110 ° C., heat treatment time 1.
5 hours, infrared average transmittance T ₁ 50%; T ₂ 26%.・ ZHT4A-2: Hydrotalcite compounds (Zn
-Mg-Al complex hydroxide salt (carbonate ion type), manufactured by Kyowa Chemical Industry Co., Ltd.), heat treatment temperature 280 ° C., a heat treatment time of 1.5 hours, the infrared average transmittance _T 1 _{23%; T} 2 14
%.・ ZHT4A: Hydrotalcite compounds (Zn-M
g-Al composite hydroxide salt (carbonate ion type, manufactured by Kyowa Chemical Industry Co., Ltd.), heat treatment temperature 110 ° C., heat treatment time 1.5 hours, infrared average transmittance T ₁ 52%; T ₂ 29
%. -Fujilein LS (A): Li-Al-Mg composite hydroxide salt (silicate ion type, manufactured by Fuji Chemical Industry Co., Ltd.), heat treatment temperature 110 ° C, heat treatment time 1.5 hours, infrared average transmittance T _{1 61%; T 2 17%} . 280 ° C-1.5
The time-heat treated product has an infrared average transmittance T ₁ 62%; T ₂
16%.

CHIMASSO which is a hindered amine compound of each of the film formulations shown in Tables 1 and 2
RB944 (manufactured by Ciba Specialty Chemicals Co., Ltd.) is made of 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}] (molecular weight: 2000-3100), and belongs to the compound of the formula (2).

The common composition of each film shown in Tables 1 and 2 except for the base resin, the inorganic filler and the hindered amine compound was 0.2% by weight of a fluorine-based surfactant (perfluoroalkylethylene oxide adduct), Phenol stabilizer (tetrakis [methylene-3-
0.1% by weight of (3 ', 5'-di-t-butyl-4'-hydroxyphenyl) propionate] methane, phosphorus stabilizer (tris (2,4-di-t-butylphenyl) phosphite) 0.1% by weight, antifogging agent (polyoxyethylene (2 mol) stearylamine monostearate)
0% by weight. In addition, wt% of the compounding amounts described in Tables 1 and 2 means wt%.

[0045]

[Table 1]

[0046]

[Table 2]

[0047]

The agricultural polyolefin resin film of the present invention has a good heat retention property due to the excellent infrared reflection and absorption of the film, and also has excellent weather resistance even in an environment where pesticides are used. Since it transmits sunlight well into the house, it is suitably used as a covering material for cultivation facilities for agricultural products.

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Claims (3)

[Claims] (1) A polyolefin resin having a content of 200 to 300
A polyolefin-based resin film for agricultural use, comprising a mixture of a hydrotalcite-based compound represented by the following formula 1 and a hindered amine-based compound heat-treated at a temperature of 0 ° C. ( ^Wherein , M ²⁺ represents a divalent metal ion, and M ³⁺ represents 3)
Valent metal ion, ^An- is an n-valent anion, x is 0 <x
A number in the range of ≦ 0.5, m indicates a number in the range of 0 ≦ m ≦ 5. ) 2. A divalent metal ion (M ²⁺ ) of a hydrotalcite compound is a magnesium ion (Mg ²⁺ ).
The trivalent metal ion (M ³⁺ ) is an aluminum ion (Al ³⁺ ), and the n-valent anion (A ⁿ⁻ ) is a carbonate ion (CO ₃ ²⁻ ). The polyolefin resin film for agricultural use according to the above. 3. The composition according to claim 1, wherein said hydrotalcite compound contains 7.5% by weight of said hydrotalcite compound.
In a low-density polyethylene film of 00 μm, the average value of the infrared transmittance at a wavelength of 6.3 to 6.6 μm is 15 to 25.
%, And the average value of infrared transmittance at a wavelength of 14 to 25 μm is 5 to 15%.
The polyolefin resin film for agricultural use according to the above.