JP2016054732A - Agricultural multifilm having heat retaining property and transparency - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an agricultural multifilm having availability together with heat-retaining property of a light.SOLUTION: Containing, to 100 parts by weight of a synthetic resin, a compound of hydrotalcites which is represented by the following general formula (1), MgAl(OH)(CO) mHO (1), (where X is in the range of 4.0<X≤6.5; and m represents 0 or a positive number), and in which a molar ratio Rdetermined from 2θ of the face by X-ray diffraction method (110) and a molar ratio Rdetermined from a chemical analysis satisfy |R-R|≤0.7 imparts transparency simultaneously with heat-retaining property to an agricultural multifilm.SELECTED DRAWING: None

Description

The present invention relates to an agricultural multi-film utilizing the heat retaining property and transparency of a film.

Agricultural multi-film directly covers the ground and is used to maintain underground temperature, prevent moisture evaporation, and prevent soil erosion. Above all, transparent multi-films are mainly used for the effect of increasing the ground temperature because they transmit sunlight. However, the transparent multi-film has a problem that the heat-dissipation effect at night is strong and the heat-retaining effect cannot be sufficiently obtained even if the temperature increase effect during the day is superior to the colored multi-film.
So far, hydrotalcite (Patent Document 1) in which the particle surface is coated with an oxysilicate compound and / or a phosphoric acid compound has been proposed as a heat insulating agent for agricultural film to be contained in a resin for agricultural film, There is a need for further improvement in heat retention because of insufficient heat retention.

JP2003-231778

An object of the present invention is to provide an agricultural multi-film having both a daytime ground temperature increasing effect and a nighttime heat retaining effect by using a film having both transparency and heat retaining properties.

It is represented by the following general formula (1) with respect to 100 parts by weight of the synthetic resin,
Mg _X Al ₂ (OH) _{2X + 4} (CO ₃ ) · mH ₂ O (1)
(X in the above formula is in the range of 4.0 <X ≦ 6.5, and m represents 0 or a positive number.)
Hydrotalcite compounds having a molar ratio R ₁ determined from 2θ of (110) plane by X-ray diffraction method and a molar ratio R ₂ determined from chemical analysis satisfying | R ₁ −R ₂ | ≦ 0.7 are 1 to An agricultural multi-film comprising a transparent film containing 20 parts by weight.
However, the molar ratio is a value of the Mg / Al ₂ ratio.

ADVANTAGE OF THE INVENTION According to this invention, the multifilm for agriculture which has heat retention and transparency is provided. In particular, when it is used for the purpose of germination and seedling of plants, it contributes to maintaining sufficient temperature and light quantity necessary for growth.

In addition to providing stable temperature and light conditions, it is possible to accelerate the seasonal growth stage and grow plants in warm regions in cold regions.

The heat retaining agent used in the present invention is represented by the following formula (1):
Mg _X Al ₂ (OH) _{2X + 4} (CO ₃ ) · mH ₂ O (1)
(X in the above formula is in the range of 4.0 <X ≦ 6.5, and m represents 0 or a positive number.)
X is in the range of 4.0 <X ≦ 6.5, preferably 4.3 ≦ X ≦ 6.3, and more preferably in the range of 4.5 ≦ X ≦ 6.0. m represents 0 or a positive number. m is preferably 0 to 5, more preferably 0 to 4.

In the hydrotalcite compound, part of the octahedral structure of brucite is composed of a combination of trivalent metal ions such as Al. The unit cell a ₀ obtained from the (110) plane of the X-ray diffraction peak pattern varies depending on the metal element radius of the octahedral structure, and the molar ratio of hydrotalcite can be calculated by obtaining the distance of this a _0. I can do it. In the case of this hydrotalcite composed of Mg—Al, it can be expressed by the following formula (2).

3.147-a ₀ = 0.33543y (2)
a ₀ : unit lattice distance obtained from XRD y = Al / (Al + Mg)
By using the above formula (2), y can be obtained from a ₀ calculated from the X-ray diffraction angle, and the molar ratio can be obtained from y.

The inventor of the present invention uses a hydrotalcite compound represented by the above formula (1) to obtain a molar ratio R ₁ determined from 2θ of (110) plane by X-ray diffraction method and a molar ratio R ₂ calculated from chemical analysis of 0.00. It has been found that satisfying 05 ≦ | R ₁ −R ₂ | ≦ 0.7 improves the heat retention and transparency of the film when blended into a synthetic resin to form a film. That is, the difference in molar ratio is 0.05 ≦ | R ₁ −R ₂ | ≦ 0.7, preferably 0.05 ≦ | R ₁ −R ₂ | ≦ 0.5, more preferably 0.05 ≦ | R. ₁ −R ₂ | ≦ 0.4, and when it is higher than 0.7, desired transparency cannot be obtained.

The film of the present invention contains 1 to 20 parts by weight, preferably 1 to 15 parts by weight of a hydrotalcite compound as a heat insulating agent with respect to 100 parts by weight of the resin. When the content of the heat-retaining agent is less than 1 part by weight, the effect as a heat-retaining agent is small.

The average secondary particle diameter of the hydrotalcite compound particles used in the present invention is preferably 0.1 to 3.0 μm, more preferably 0.2 to 1.5 μm. The BET method specific surface area of the heat insulating material is preferably 5 to 50 m ² / g, more preferably 5 to 30 m ² / g. When the average secondary particle diameter is smaller than 0.1 μm or when the specific surface area is larger than 50 m ² / g, it may be difficult to disperse in the resin. When the average secondary particle diameter is larger than 3.0 μm When kneaded into a resin, the transparency of the film may deteriorate.

The present inventor found that when the hydrotalcite compound was kneaded into the LEDP resin by 10% by weight, the heat retention index determined from the Kaiser area was 60 or higher, and the haze value was not higher than 35% than the film containing no heat insulating agent. It was found that the material is an excellent synthetic resin film, and that the heat insulating agent reaching the purpose is a hydrotalcite compound satisfying the above conditions.

The heat retention agent used in the present invention may be hydrotalcite compound particles obtained by baking hydrotalcite compound particles at 200 to 350 ° C. and decrystallizing water.

The resin blended with the hydrotalcite compound particles used in the present invention may be any resin that can be used as a film. Examples thereof include polyethylene, polypropylene, ethylene / propylene copolymer, polybutene, and poly-4-methyl. Polymers or copolymers of C _{2 to} C ₈ olefins (α-olefins) such as pentene-1 and the like, copolymers of these olefins and dienes, ethylene-acrylate copolymers, polystyrene, ABS resins, AAS resins AS resin, MBS resin, ethylene / vinyl chloride copolymer resin, ethylene vinyl acetate copolymer resin, ethylene-vinyl chloride-vinyl acetate graft polymerization resin, vinylidene chloride, polyvinyl chloride, chlorinated polyethylene, chlorinated polypropylene, vinyl chloride propylene copolymer, Vinyl acetate resin, phenoxy resin, polyacetal, poly Amide, polyimide, polycarbonate, polysulfone, polyphenylene oxide, polyphenylene sulfide, polyethylene terephthalate, polybutylene terephthalate, thermoplastic resins such as methacrylic resin can be exemplified.

Preferred examples of these thermoplastic resins include polyolefins or copolymers thereof, specifically, polypropylene homopolymers, polypropylene resins such as ethylene propylene copolymers, high density polyethylene, low density polyethylene, Linear low density polyethylene, ultra low density polyethylene, EVA (ethylene vinyl acetate resin), EEA (ethylene ethyl acrylate resin), EMA (ethylene methyl acrylate copolymer resin), EAA (ethylene acrylic acid copolymer resin), ultra Polyethylene resins such as high molecular weight polyethylene, and polymers or copolymers of C _{2 to} C ₆ olefins (α-ethylene) such as polybutene and poly-4-methylpentene-1.

The hydrotalcite compound particles are preferably subjected to a surface treatment. As surface treatment agents, higher fatty acids, anionic surfactants, phosphate esters, coupling agents (silane, titanate, aluminum), polyhydric alcohol and fatty acid esters, acrylic polymers, silicone treatment agents, etc. And at least one selected from the group consisting of:

Examples of higher fatty acids include higher fatty acids having 10 or more carbon atoms such as stearic acid, erucic acid, palmitic acid, lauric acid, and behenic acid. Moreover, the alkali metal salt of the said higher fatty acid is mentioned. As anionic surfactants, sulfate esters of higher alcohols such as stearyl alcohol and oleyl alcohol, sulfate esters of polyethylene glycol ether, amide bond sulfate esters, ester bond sulfate esters, ester bond sulfonates, amide bond sulfonates , Ether bond sulfonate, ether bond alkylaryl sulfonate, ester bond alkylaryl sulfonate, amide bond alkylaryl sulfonate, and the like. Examples of phosphate esters include mono- or diesters such as orthophosphoric acid and oleyl alcohol, stearyl alcohol, or a mixture of both, and their acid forms, alkali metal salts, amine salts, and the like. As silane coupling agents, vinylethoxysilane, vinyl-tris (2-methoxy-ethoxy) silane, gamma-methacryloxypropyltrimethoxysilane, gamma-aminopropyltrimethoxysilane, beta (3,4-epoxycyclohexyl) ethyl Examples include trimethoxysilane, gamma-glycidoxypropyltrimethoxysilane, and gamma-mercaptopropyltrimethoxysilane. Examples of titanate coupling agents include isopropyl triisostearoyl titanate, isopropyl tris (dioctyl pyrophosphate) titanate, isopropyl tri (N-aminoethyl-aminoethyl) titanate, isopropyl tridecylbenzenesulfonyl titanate, and the like. Examples of the polyhydric alcohol and fatty acid ester include aluminum coupling agents such as acetoalkoxyaluminum diisopropylate, glycerin monostearate, and glycerin monooleate.

In order to perform the surface coating treatment of the hydrotalcite compound particles using the surface treatment agent, it can be carried out by a known wet or dry method. For example, as a wet method, a surface treatment agent may be added in a liquid or emulsion form to a hydrotalcite slurry and mechanically mixed sufficiently at a temperature up to about 100 ° C. As a dry method, the hydrotalcite powder may be added in a liquid, emulsion, or solid form with sufficient stirring with a mixer such as a Henschel mixer, and mixed sufficiently under heating or non-heating. The addition amount of the surface treatment agent can be appropriately selected, but is preferably about 10% by weight or less based on the weight of the heat retaining agent used in the present invention.

In order to increase the acid resistance of the heat retaining agent, the surface of the hydrotalcite compound particles can be coated with an inorganic compound having acid resistance. The inorganic compound having acid resistance is, for example, an oxide or hydroxide of one or more elements selected from the group consisting of silicon, aluminum, titanium, zirconia, zinc and boron. These acid-resistant coating agents are preferably 2% by weight or less based on the heat insulating agent.
If necessary, the surface of the heat insulating agent of the present invention coated with the surface can be subjected to a surface treatment with one or more of the above surface treatment agents.

The surface-treated heat retention agent can be used by appropriately selecting means such as water washing, dehydration, granulation, drying, pulverization, and classification, if necessary.

The transparency of the agricultural multifilm of the present invention is evaluated by the haze value measured according to the measurement method described later. The haze value is preferably 7.0 or less, and more preferably 6.0 or less.

The heat retention index of the agricultural multifilm of the present invention is evaluated by the heat retention index measured according to the measurement method described later. The heat retention index is preferably 60 or more, more preferably 65 or more.

The agricultural multi-film of the present invention may be provided with a plurality of planting holes. The size of the hole for planting and the distance between the holes are preferably matched to the size and occupied area of the plant body to be used.

EXAMPLES Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited to these examples. In Examples, (a) average secondary particle diameter of hydrotalcite compound particles, (b) BET specific surface area, (c) molar ratio by chemical analysis, (d) molar ratio by X-ray diffraction method, and agriculture The multi film (e) heat retention index and (f) haze value were measured by the methods described below.
(A) Average secondary particle diameter: It was measured using a MICROTRAC particle size analyzer (manufactured by NIKKISO, MT3000II series). 700 mg of the sample powder is added to 70 mL of water and dispersed for 3 minutes with ultrasonic waves (manufactured by NISSEI, MODEL US-300, current of 280 μA). Then, 2 to 4 mL of the dispersion is taken and 250 mL of deaerated water is added. The particle size distribution was measured after the suspension was circulated for 2 minutes by operating the analyzer. A total of two measurements were performed, and the arithmetic average value of the 50% cumulative secondary particle diameter obtained for each measurement was calculated to obtain the average secondary particle diameter of the sample.
(B) BET specific surface area: measured by a nitrogen adsorption method.
(C) Molar ratio by chemical analysis: The sample was dissolved in acid, and the Mg and Al contents in the solution were measured by chelate titration.
(D) Molar ratio by X-ray diffraction method: The angle of the (110) plane was read from the XRD pattern of hydrotalcite, and the molar ratio of hydrotalcite was calculated from 2θ.
(E) Thermal insulation index: A film having a thickness of 100 μm was prepared, an absorption pattern was measured by FT-IR, and the film was calculated from the absorption intensity from 2000 cm ⁻¹ to 400 cm ⁻¹ .
(F) Haze value: Using a Nippon Denshoku haze meter, the haze of a 100 μm thick film was measured.

(Synthesis Example 1)
Prepare a glass beaker with 240 mL of a 1.5 mol / L aqueous solution of magnesium chloride and 120 mL of a 1 mol / L aqueous solution of liquid aluminum chloride. The mixed solution thus mixed was simultaneously poured into a 1 L-volume reaction tank filled with a small amount of water in advance so as to have a pH of 9.5 with stirring to obtain a reaction product. 700 mL of the obtained reaction product was hydrothermally treated at 130 ° C. for 6 hours. After cooling, the whole amount was taken out and heated to 80 ° C., and an 80 ° C. aqueous solution of 1.55 g of sodium stearate prepared in advance was gradually added with stirring and maintained for 30 minutes. Thereafter, the cake obtained by solid-liquid separation with Nutsche and washed with 800 mL of ion exchange water was dried at 105 ° C. for 18 hours. The obtained dried product was pulverized with a hammer mill and sieved with a 150-micron filter. The chemical formula of the obtained hydrotalcite compound was Mg _5.9 Al ₂ (CO ₃ ) (OH) _15.9 · 4.0H ₂ O.

The average secondary particle diameter of this hydrotalcite compound was 0.26 μm, and the BET specific surface area was 17 m ² / g. Furthermore, since the molar ratio determined from 2θ of the (110) plane by X-ray diffraction of this substance was 6.03 and the molar ratio by chemical analysis was 5.93, these differences were 0.10. there were.

4 g of the hydrotalcite compound particles obtained here and 36 g of LDPE manufactured by Sumitomo Chemical were kneaded at 130 ° C. using a Brabender plast mill, and then formed at 160 ° C. using a hydraulic compression molding machine. As a result, the heat retention index of the obtained film was 69.33 and the haze value was 5.7.

An agricultural multi-film in which a fixed planting hole having a diameter of 5 cm was provided at the center of the film obtained in Synthesis Example 1 having a width of 150 cm, a length of 150 cm, and a thickness of 0.02 mm was produced.

(Comparative Synthesis Example 1)
Prepare 154 mL of magnesium chloride 1.5 mol / L aqueous solution and 120 mL of liquid aluminum chloride 1 mol / L aqueous solution in a glass beaker, and add 8 mL of sodium hydroxide 8 mol / L aqueous solution and 60 mL of sodium carbonate 1 mol / L aqueous solution so that they disappear simultaneously. The mixed solution thus mixed was simultaneously poured into a 1 L-volume reaction tank filled with a small amount of water in advance so as to have a pH of 9.5 with stirring to obtain a reaction product. 700 mL of the obtained reaction product was hydrothermally treated at 170 ° C. for 6 hours. After cooling, the whole amount was taken out and heated to 80 ° C., and a preliminarily prepared sodium stearate 0.55 g 80 ° C. aqueous solution was gradually added with stirring and maintained for 30 minutes. Thereafter, the cake obtained by solid-liquid separation with Nutsche and washed with 800 mL of ion exchange water was dried at 105 ° C. for 18 hours. The obtained dried product was pulverized with a hammer mill and sieved with a 150-micron filter. The chemical formula of the obtained hydrotalcite compound was Mg _3.9 Al ₂ (CO ₃ ) (OH) _11.7 · 2.9H ₂ O.

This hydrotalcite compound had an average secondary particle size of 0.85 μm and a BET specific surface area of 11 m ² / g. Furthermore, since the molar ratio determined from 2θ of the (110) plane by X-ray diffraction of this substance was 4.74 and the molar ratio by chemical analysis was 3.85, the difference between these was 0.89. there were.

4 g of the hydrotalcite compound particles obtained here and 36 g of LDPE manufactured by Sumitomo Chemical were kneaded at 130 ° C. by a plast mill manufactured by Brabender, and then formed into a film at 160 ° C. using a hydraulic compression molding machine. As a result, the heat retention index was 63.82 and the haze value was 10.1.

(Comparative Example 1)
An agricultural multi-film in which a hole for planting having a diameter of 5 cm was provided at the center of the film obtained in Comparative Synthesis Example 1 having a width of 150 cm, a length of 150 cm, and a thickness of 0.02 mm was produced.

The agricultural multi-film produced in Example 1 or the agricultural multi-film produced in Comparative Example 1 was transferred to the outdoor environment on the premises of Hayashida-cho, Sakaide City, Kagawa Prefecture on May 9, 2014. The ground was covered so that the bottom 30 cm was buried in the soil, and the ground temperature at a depth of 5 cm from the ground surface in each film was measured at 1 hour intervals from 0:00 to 24:00 on May 10, 2014.

As a result, the ground temperature covered with the agricultural film produced in Example 1 was always equal to or higher than the ground temperature covered with the agricultural film produced in Comparative Example 1 (Table 1).

Although the embodiments considered to be representative of the present invention have been described above, the present invention is not necessarily limited to the structures shown in these embodiments. For example, the size, arrangement, and number of planting holes provided in the agricultural multi-film of the present invention are arbitrarily determined in consideration of the size and occupied area of the plant body to be used and the durable strength during tension. It is possible to change and implement.

Claims (2)

It is represented by the following general formula (1) with respect to 100 parts by weight of the synthetic resin,

Mg _X Al ₂ (OH) _{2X + 4} (CO ₃ ) · mH ₂ O (1)
(X in the above formula is in the range of 4.0 <X ≦ 6.5, and m represents 0 or a positive number.)

Hydrotalcite compounds having a molar ratio R ₁ determined from 2θ of (110) plane by X-ray diffraction method and a molar ratio R ₂ determined from chemical analysis satisfying | R ₁ −R ₂ | ≦ 0.7 are 1 to An agricultural multi-film comprising a transparent film containing 20 parts by weight.
However, the molar ratio is a value of the Mg / Al ₂ ratio.
The agricultural multi-film according to claim 1, wherein a fixed planting hole for planting is provided.