JP6886232B2 - Agricultural film - Google Patents

Description

The present invention relates to a film used for agriculture, and more particularly to an agricultural film and a biodegradable film for agriculture, which are excellent in raising and retaining heat of soil temperature, suppressing the growth of weeds, and do not leave copper in the soil.

Recently, agricultural films are often used for the purpose of raising the soil temperature and keeping the soil warm. A colorless and transparent mulch film is used especially for the purpose of raising the soil temperature. On the other hand, a black mulch film is used when the control of weed growth is more important than the rise in soil temperature.

However, a colorless and transparent film has a high soil temperature because it transmits sunlight well, which is advantageous for promoting the growth of crops. However, weeds absorb fertilizer and soil heat and grow, and overgrown weeds lift the film. It will damage it. As a result, the effect of the mulch film is reduced. In addition, weeding in the mulch film is often required, which requires a great deal of labor.

On the other hand, when a black mulch film is used, the growth of weeds is greatly suppressed because sunlight is almost completely blocked, but it is difficult to raise the soil temperature.

As a result, a green mulch film has been developed as having both a weed control function and a soil temperature rise function, and has been widely used in recent years. Many of the pigments used in this green multi-film use techniques such as combining green pigments such as phthalocyanine green and pigment green, and blue pigments such as phthalocyanine blue with other pigments. (Patent Document 1).

However, the pigments used in these techniques contain copper. The copper component is one of the substances that inhibit the growth of rice in the "Act on Soil Contamination of Agricultural Land", and since the standard value of copper is set for the soil of rice fields, it is originally an agricultural film. It cannot be said that it is preferable as an ingredient to be used as an ingredient.

In addition, many studies using biodegradable materials have been conducted as one of the solutions for reducing the recent waste problem and the recovery work of agricultural mulch film. Typical examples of biodegradable materials include aliphatic polyester resins such as polylactic acid, polybutylene succinate and polybutylene succinate adipate, and aromatic-aliphatic copolymer polyester resins such as polybutylene adipate terephthalate. , Various studies have been conducted.

Since these biodegradable materials can be decomposed by microorganisms living in the soil, it is not necessary to recover agricultural mulch films using this biodegradable material, and they are decomposed in the soil after use. It is possible to make it.

When these biodegradable materials are used as agricultural mulch films, when pigments containing copper components as described above are used, the mulch films are decomposed by microorganisms in the soil after use, but they are used for films. There was a problem that a large amount of the copper component in the mulch was left in the soil.

Japanese Unexamined Patent Publication No. 3-155717

In view of such problems, it is an object of the present invention to provide an agricultural film and an agricultural biodegradable film which are excellent in raising and retaining heat of soil temperature and suppressing the growth of weeds and which do not leave a copper component in the soil. To do.

As a result of diligent studies, the present inventors have found that the film is an agricultural film composed of a thermoplastic resin composition containing a pigment containing no copper component, and the average value of the total light transmittance in the wavelength range of 640 to 690 nm ( We have found that an agricultural film having an A) of 40% or less and an average value (B) of all light transmittances in the wavelength range of 400 to 700 nm of 15% or more can solve the above problems, and has reached the present invention.

That is, the gist of the present invention is
[1] The average value (A) of the total light transmittance in the wavelength range of 640 to 690 nm is 40% or less, and the average value of the total light transmittance in the wavelength range of 400 to 700 nm, which contains a pigment containing no copper component. An agricultural film characterized in that (B) is 15% or more.
[2] The agricultural film according to [1], which contains at least pigment yellow as a pigment.
[3] The agricultural film according to [1] or [2], wherein the average value (C) of the total light transmittance in the wavelength range of 5 to 25 μm is 55% or less.
[4] The agricultural film according to any one of [1] to [3], wherein the average value (D) of the total light transmittance in the wavelength range of 420 to 470 nm is 50% or less. ..
[5] The agricultural film according to any one of [1] to [4], which contains a biodegradable resin as a resin component.
[6] The agricultural film according to [5], wherein the thickness is 50 μm or less.
Regarding.

INDUSTRIAL APPLICABILITY According to the present invention, it is possible to provide an agricultural film and an agricultural biodegradable film which are excellent in raising and retaining the soil temperature and suppressing the growth of weeds and do not leave a copper component in the soil.

The agricultural film of the present invention contains a pigment that does not contain a copper component, and the average value (A) of the total light transmittance in the wavelength range of 640 to 690 nm is 40% or less, and the total light rays in the wavelength range of 400 to 700 nm. It is important that the average transmittance (B) is 15% or more.

In the agricultural film of the present invention, it is important that the average value (A) of the total light transmittance in the wavelength range of 640 to 690 nm is 40% or less, preferably 35% or less, and 32% or less. It is more preferable than there is, and it is more preferable that it is 30% or less. By setting the average value (A) of the total light transmittance in the wavelength range of 640 to 690 nm in the above range, the photosynthesis of weeds can be efficiently suppressed and the growth of weeds can be suppressed.

Further, in the agricultural film of the present invention, it is important that the average value (B) of the total light transmittance in the wavelength range of 400 to 700 nm is 15% or more, preferably 16% or more, and preferably 17%. The above is more preferable, 19% or more is further preferable, and 25% or more is particularly preferable. By setting the average value (B) of the total light transmittance in the wavelength range of 400 to 700 nm to the above range, it is possible to transmit the light required for the temperature rise in the soil at the portion covered with the agricultural film. , The rise in soil temperature during the day can be made more favorable.

In the agricultural film of the present invention, the average value (C) of the total light transmittance in the wavelength range of 5 to 25 μm is preferably 55% or less, more preferably 53% or less, and more preferably 50% or less. Is even more preferable. By setting the average value (C) of the total light transmittance in the wavelength range of 5 to 25 μm in the above range, the temperature in the soil at the place covered with the agricultural film is the temperature of the ground temperature even after the sun goes down. Can be efficiently suppressed.

In the agricultural film of the present invention, the average value (D) of the total light transmittance in the wavelength range of 420 to 470 nm is preferably 50% or less, more preferably 48% or less, and 45% or less. It is more preferable, and it is particularly preferable that it is 30% or less. By setting the average value (D) of the total light transmittance in the wavelength range of 420 to 470 nm in the above range, normal morphogenesis of weed leaves can be suppressed, and weed growth can be further suppressed. it can.

The pigment used in the agricultural film of the present invention is not particularly limited as long as it is a pigment that does not contain a copper component, and the average value (A) of the total light transmittance in the wavelength range of 640 to 690 nm is 40% or less. Yes, a pigment formulated so as to satisfy the condition that the average value (B) of the total light transmittance in the wavelength range of 400 to 700 nm is 15% or more can be used.

For example, oxides such as titanium dioxide, zinc oxide and iron oxide, inorganic pigments such as talc, clay, ultramarine and dark blue silicates, and organic pigments such as azo pigments and polycyclic pigments. These pigments can be used alone or in combination of two or more. Of these, it is preferable to use a pigment yellow pigment, which is an organic pigment. By using the pigment yellow pigment, the average value (A) of the total light transmittance in the wavelength range of 640 to 690 nm, which is close to the complementary color wavelength of the pigment yellow pigment, and the total light transmittance in the wavelength range of 420 to 470 nm can be obtained. The value of the average value (D) can be efficiently reduced.

The term "pigment containing no copper component" means that the pigment does not substantially contain a copper component, and by using the pigment, the pigment is substantially contained in the agricultural film of the present invention. Means that it does not contain copper components. Therefore, the agricultural film of the present invention also includes a copper component contained in an inactive manner and a film containing a very small amount of copper component that does not affect the environment in the soil.

The pigment component used in the present invention is preferably 0.1 to 10 parts by mass, more preferably 0.2 to 7 parts by mass, and 0.3, based on the total mass of the resin component. It is more preferably ~ 5 parts by mass. Further, the pigment yellow is preferably contained in an amount of 5 to 95 parts by mass, more preferably 10 to 90 parts by mass, and particularly preferably 19 to 80 parts by mass with respect to the total mass of the pigment component. By setting the content of the pigment component with respect to the total mass of the resin component in the above range, the average value (A) of the total light transmittance in the wavelength range of 640 to 690 nm is 40% or less, and 400 to 700 nm. It becomes easy to manufacture an agricultural film in which the average value (B) of the total light transmittance in the wavelength range is 15% or more.

The material used for the agricultural film of the present invention is not particularly limited, and a known thermoplastic resin can be used. For example, polyvinyl chloride, polyethylene terephthalate, polyamide, polyethylene, polypropylene, polycarbonate, polyethylene naphthalate, ethylene / vinyl acetate copolymer, ionomer, acrylic acid ester, methacrylic acid ester, aliphatic aromatic polyester, aliphatic polyester. Biodegradable resins such as can be used. Above all, the biodegradable resin can be preferably used in the present invention because it can be decomposed in the soil after being used as an agricultural film.

The biodegradable resin that can be used in the agricultural film of the present invention is not particularly limited, and a generally available biodegradable resin can be used. For example, polycaprolactone, polyamide, polyvinyl alcohol, cellulose ester, lactic acid polyester resin, aliphatic polyester resin, aliphatic-aromatic polyester resin and the like can be mentioned. Among them, considering the productivity when producing a film, the workability when spreading in a field, and the biodegradability after use, an aliphatic aromatic polyester resin, an aliphatic polyester resin, and a lactic acid polyester resin Etc. are preferred.

<Alphatic aromatic polyester resin>
The aliphatic aromatic polyester resin that can be used in the present invention contains an aliphatic dicarboxylic acid unit, an aromatic dicarboxylic acid unit, a chain aliphatic and / or an alicyclic diol unit, and is an aromatic dicarboxylic acid unit. The content is 5 to 60 mol% based on the total amount of the aliphatic dicarboxylic acid unit and the aromatic dicarboxylic acid unit (100 mol%).

Specifically, the aliphatic aromatic polyester resin that can be used in the present invention is, for example, an aliphatic diole unit represented by the following formula (1) or an aliphatic dicarboxylic acid represented by the following formula (2). The unit and the aromatic dicarboxylic acid unit represented by the following formula (3) are essential components.

-O-R1-O- (1)
(In the formula, R1 represents a divalent chain aliphatic hydrocarbon group and / or a divalent alicyclic hydrocarbon group, and is not limited to one type when copolymerized.)
-OC-R2-CO- (2)
(In the formula, R2 shows a direct bond or a divalent chain aliphatic hydrocarbon group and / or a divalent alicyclic hydrocarbon group, and is not limited to one when copolymerized. .)
-OC-R3CO- (3)
(In the formula, R3 represents a divalent aromatic hydrocarbon group, and when copolymerized, it is not limited to one type.)
The diol component giving the diol unit of the formula (1) usually has 2 to 10 carbon atoms, and is, for example, ethylene glycol, 1,3-propanediol, 1,4-butanediol, or 1,4-cyclohexanedim. Examples include methanol. Among them, a diol having 2 or more and 4 or less carbon atoms is preferable, ethylene glycol and 1,4-butanediol are more preferable, and 1,4-butanediol is particularly preferable.

The dicarboxylic acid component giving the dicarboxylic acid unit of the formula (2) usually has 2 or more and 10 or less carbon atoms, and examples thereof include succinic acid, adipic acid, suberic acid, sebacic acid, and dodecanedioic acid. Of these, succinic acid or adipic acid is preferable.

Examples of the aromatic dicarboxylic acid component giving the aromatic dicarboxylic acid unit of the formula (3) include terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid and the like. Among them, terephthalic acid and isophthalic acid are preferable, and terephthalic acid is particularly preferable. preferable. In addition, an aromatic dicarboxylic acid in which a part of the aromatic ring is replaced with a sulfonate can be mentioned. Two or more types of the aliphatic dicarboxylic acid component, the aliphatic diol component, and the aromatic dicarboxylic acid component can be used.

The aliphatic aromatic polyester resin in the present invention may contain an aliphatic oxycarboxylic acid unit. Specific examples of the aliphatic oxycarboxylic acid giving the aliphatic oxycarboxylic acid unit include lactic acid, glycolic acid, 2-hydroxy-n-butyric acid, 2-hydroxycaproic acid, 6-hydroxycaproic acid, 2-hydroxy-3, Examples thereof include 3-dimethylbutyric acid, 2-hydroxy-3-methylbutyric acid, 2-hydroxyisocaproic acid, or a mixture thereof. Further, these lower alkyl esters or intramolecular esters may be used. When optical isomers are present in these, any of D-form, L-form, and racemic form may be used, and the form may be any of solid, liquid, and aqueous solution. Of these, lactic acid or glycolic acid is preferred. These aliphatic oxycarboxylic acids can be used alone or as a mixture of two or more kinds.

The amount of the aliphatic oxycarboxylic acid is preferably 0 to 30 mol%, more preferably 0.01 to 20 mol%, based on all the constituents constituting the aliphatic aromatic polyester resin.

The melt flow rate (MFR) of the aliphatic aromatic polyester resin in the present invention is preferably 0.1 to 100 g / 10 minutes, more preferably 0.1 when measured at 190 ° C. and a load of 2.16 kg. It is ~ 50 g / 10 minutes, and particularly preferably 0.1 to 30 g / 10 minutes.

Specific examples of such an aliphatic aromatic polyester resin include "Ecoflex" manufactured by BASF and "EnPol" manufactured by S-EnPol.

<Alphatic polyester resin>
As the aliphatic polyester ester resin that can be used in the present invention, an aliphatic polyester resin containing an adipic acid unit as a dicarboxylic acid unit, an aliphatic polyester resin not containing an adipic acid unit as a dicarboxylic acid unit, or the like can be used. ..

The aliphatic polyester-based resin, which is a constituent component of the aliphatic polyester-based resin that can be used in the present invention, is preferably an aliphatic polyester-based resin containing an aliphatic diol unit and an aliphatic dicarboxylic acid unit as main components. Here, the "main component" is based on the entire monomer unit constituting the aliphatic polyester (100 mol%), and the aliphatic diol unit and the aliphatic dicarboxylic acid unit are 70 mol% or more, preferably 80 mol%. % Or more, more preferably 90 mol% or more.

Specific examples of the aliphatic polyester resin include a chain aliphatic and / or alicyclic diol unit represented by the following formula (4), and a chain aliphatic represented by the following formula (5). And / or an alicyclic dicarboxylic acid unit.

-O-R4-O- (4)
(In the formula, R4 represents a divalent chain aliphatic hydrocarbon group and / or a divalent alicyclic hydrocarbon group. When copolymerized, two or more kinds of R4 are contained in the resin. It may be.)
-OC-R5-CO- (5)
(In the formula, R5 represents a divalent chain aliphatic hydrocarbon group and / or a divalent alicyclic hydrocarbon group. When copolymerized, two or more kinds of R5 are contained in the resin. It may be.)
In the above formulas (4) and (5), the "divalent chain aliphatic hydrocarbon group and / or the divalent alicyclic hydrocarbon group" is a divalent chain aliphatic hydrocarbon. It means that it may contain both a group and a divalent aliphatic hydrocarbon group. In addition, the "chain aliphatic and / or alicyclic" may be abbreviated as "aliphatic" below.

The aliphatic polyester resin contains 1,4-butanediol unit as an essential component as the diol unit of the above formula (4). The content of 1,4 butanediol units is preferably 30 to 60 mol%, particularly 40 to 50 mol%, based on the entire monomer unit constituting the aliphatic polyester resin (100 mol%). ..

The diol unit other than the 1,4 butanediol unit is not particularly limited, but an aliphatic diol unit having 3 to 10 carbon atoms is preferable, and an aliphatic diol unit having 4 to 6 carbon atoms is particularly preferable. Specific examples thereof include 1,3-propanediol and 1,4-hexanedimethanol. Two or more kinds of diol components giving the aliphatic diol unit can also be used.

The aliphatic polyester resin further contains a succinic acid unit as an essential component as a dicarboxylic acid unit.

When the aliphatic polyester resin contains adipic acid as an essential component as a dicarboxylic acid unit, the content of the adipic acid unit is based on the entire monomer unit constituting the aliphatic polyester resin (100 mol%). , 0.5 to 20 mol%, more preferably 1 to 15 mol%.

The dicarboxylic acid unit other than the succinic acid unit and the adipic acid unit is not particularly limited, but an aliphatic dicarboxylic acid unit having 2 to 10 carbon atoms is preferable, and an aliphatic dicarboxylic acid unit having 4 to 8 carbon atoms is particularly preferable. Specific examples thereof include suberic acid, sebacic acid, dodecanedioic acid and the like. Two or more kinds of dicarboxylic acid components giving the aliphatic dicarboxylic acid unit can also be used.

Further, the aliphatic polyester resin may contain an aliphatic oxycarboxylic acid unit. Specific examples of the aliphatic oxycarboxylic acid giving the aliphatic oxycarboxylic acid unit include lactic acid, glycolic acid, 2-hydroxy-n-butyric acid, 2-hydroxycaproic acid, 6-hydroxycaproic acid, 2-hydroxy-3, Examples thereof include 3-dimethylbutyric acid, 2-hydroxy-3-methylbutyric acid, 2-hydroxyisocaproic acid and the like, or lower alcohols or intramolecular esters thereof. When optical isomers are present in these, any of D-form, L-form, and racemic form may be used, and the form may be solid, liquid, or aqueous solution. Of these, lactic acid or glycolic acid is particularly preferred. These aliphatic oxycarboxylic acids can be used alone or as a mixture of two or more kinds.

The content of the aliphatic oxycarboxylic acid unit is preferably 0 to 30 mol% based on the entire monomer unit constituting the aliphatic polyester resin (100 mol%), and further 0.01 to 20 mol%. It is preferably in mol%, particularly preferably 0.01 to 10 mol%.

Specific examples of such an aliphatic polyester resin include "GSPla" manufactured by Mitsubishi Chemical Corporation and "Bionore" manufactured by Showa Denko Corporation.

<Lactic acid polyester resin>
As the lactic acid-based polyester resin that can be used in the present invention, L-lactic acid, D-lactic acid, DL-lactic acid or a mixture thereof, homopolymers such as lactide, or copolymers can be used. The lactic acid-based polyester-based resin can be produced directly from these raw materials by dehydration condensation, ring-opening polymerization of lactide, or the like, but the production method is not particularly limited. Further, a hydroxycarboxylic acid other than lactic acid, an aliphatic polyhydric alcohol, an aliphatic polybasic acid and the like may be copolymerized to the extent that the properties of the lactic acid-based polyester resin are not impaired.

Specific examples of such a lactic acid-based polyester-based resin include "Ingeo Biopolymer" manufactured by Nature Works and "REVODE" manufactured by Zhejiang Kaisei Biomaterials Co., Ltd.

Further, it is also possible to use a raw material in which the lactic acid-based polyester-based resin produced in this manner is premixed with another aliphatic polyester-based resin or an aliphatic aromatic polyester-based resin.

Specific examples of such a mixed resin with a lactic acid polyester resin include "Ecobio F Blend C2224" manufactured by BASF Japan Ltd.

<Other ingredients>
The thermoplastic resin that can be used in the agricultural film of the present invention can further contain various conventionally known additives. Additives include, for example, crystal nucleating agents, antioxidants, antiblocking agents, slip agents, UV absorbers, lightfasteners, plasticizers, stabilizers, colorants, flame retardants, mold release agents, antistatic agents, and antistatic agents. Examples thereof include antifogging agents, surface wetting improvers, incineration aids, lubricants, dispersants, various surfactants, and antioxidants. One of these may be used alone, or two or more thereof may be mixed and used. Of these, it is particularly preferable to add a slip agent, an anti-blocking agent, and an ultraviolet absorber.

Examples of the slip agent include unsaturated fatty acid amide and unsaturated fatty acid bisamide composed of unsaturated fatty acids having 6 to 30 carbon atoms, and erucic acid amide and erucic acid bisamide are preferable.

Examples of the anti-blocking agent include saturated fatty acid amide having 6 to 30 carbon atoms, saturated fatty acid bisamide (for example, stearic acid amide, stearic acid bisamide), methylol amide, ethanol amide, natural silica, synthetic silica, synthetic zeolite, talc and the like. Be done.

Examples of the ultraviolet absorber include triazine-based, benzophenone-based, benzotriazole-based, salicylic acid-based, and cyanoacrylate-based, and among them, triazine-based, benzotriazole-based, and benzophenone-based ultraviolet absorbers are preferable.

Examples of the triazine-based ultraviolet absorber include 2- [4,6-bis (2,4-dimethylphenyl) 1,3,5-triazine-2-yl] -5- (octyloxy) phenol: CAS Number 2725-22-6. Compounds represented by (for example, Cytec's CYASORB UV-1164) and 2- (4,6-diphenyl-1,3,5-triazine-2-yl) -5-[(hexyl) oxy] -phenol: CAS Number. 147315-50-2 (for example, Tinuvin1577FF from BASF Japan), 2- [4,6-bis (diphenyl-4-yl) -1,3,5-triazine-2-yl] -5-[(2-ethylhexyl) Oxy] -phenol (eg, BASF Japan's Tinuvin 1600) can be used.

Examples of the benzotriazole-based or benzophenone-based ultraviolet absorber include 2- [5-chloro (2H) -benzotriazole-2-yl] -4-methyl6- (tert-butyl) phenol and 2- [2-hydroxy-3. , 5-Bis (α, α-dimethylbenzyl) phenyl] -2H-benzotriazole, octabenzophenone, 2,2'-dihydroxy-4-4'-dimethoxybenzophenone, 2,2'-4,4'-tetrahydrobenzophenone, etc. Can be mentioned.

Antioxidants include BHT, 2,2'-methylenebis (4-methyl-6-tert-butylphenol), pentaerythritol tetrakis [3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate]. , 3,3', 3 ", 5,5', 5" -Hexa-tert-butyl-α, α', α "-(mesitylen-2,4,6-triyl) tri-p-cresol, octadecyl- 3- (3,5-di-tert-butyl-4-hydroxyphenyl) propionate, 1,3,5-tris [(4-tert-butyl-3-hydroxy-2,6-xylyl) methyl] -1, 3,5-Triazine-2,4,6 (1H, 3H, 5H) -trione, 1,3,5-tris (3,5-di-tert-butyl-4-hydroxybenzyl) -1,3,5 -Triazine-2,4,6 (1H, 3H, 5H) -trione, calcium diethylbis [{3,5-bis (1,1-dimethylethyl) -4-hydroxyphenyl} methyl] phosphonate, bis (2, 2'-Dihydroxy-3,3'-di-tert-butyl-5,5'-dimethylphenyl) ethane, N, N'-hexane-1,6-diylbis [3- (3,5-di-tert-) Butyl) -4-hydroxyphenyl] propionamide, hindered phenolic antioxidants such as n-octadecyl 3- (3', 5'-di-t-butyl-4'-hydroxyphenyl) propionate, tridecylphosphite , Diphenyldecylphosphite, tetrakis (2,4-di-tert-butylphenyl) [1,1-biphenyl] -4,4'-diylbisphosphonite, bis [2,4-bis (1,1-bis) Dimethylethyl) -6-methylphenyl] ethyl ester phosphite, phosphorus-based antioxidants such as bis (2,4-di-tert-butylphenyl) pentaerythritol diphosphite, 3-hydroxy-5,7-di Lactone-based antioxidants such as the reaction product of -tert-butyl-furan-2-one and xylene, sulfur-based antioxidants such as dilaurylthiodipropionate and distearylthiodipropionate, and two or more of them. Examples thereof include a mixture of.

Examples of the stabilizer include fatty acid metal salts. The fatty acid component of the fatty acid metal salt is a chain carboxylic acid having a carboxyl group and usually having 6 to 30 carbon atoms, which may be linear or branched, and may have an unsaturated bond only by a saturated bond. May be good. Specific examples of fatty acids include caproic acid, caprylic acid, caproic acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachidic acid, behenic acid, montanic acid, palmitreic acid, oleic acid, eicosenoic acid, erucic acid, and elaidic acid. , Trans 11 elaidic acid, trans 13 docosenoic acid, linoleic acid, linolenic acid, myristic acid, erucic acid and the like.

On the other hand, as the metal atom, atoms of groups 1A, 2A, 2B and 3B in the periodic table are preferable. Preferred examples include sodium, potassium, calcium, magnesium, barium, aluminum, zinc and the like.

Examples of the fatty acid metal salt include calcium stearate, magnesium stearate, barium stearate, aluminum stearate, zinc stearate, calcium laurate, magnesium laurate, aluminum laurate, sodium montanate and the like. These may be used alone or in combination of two or more. Among these, calcium stearate, magnesium stearate, aluminum stearate, calcium laurate, magnesium laurate and aluminum laurate are preferable.

Examples of the dispersant include ester waxes such as Montan wax.

Further, the aliphatic polyester resin composition of the present invention includes biodegradable resins and natural products such as polycaprolactone, polyamide, polyvinyl alcohol, cellulose ester and the like, starch, cellulose, etc., as long as the effects of the present invention are not impaired. Fine powders of animal / vegetable substances such as paper, wood flour, chitin / chitosanic, coconut shell powder, walnut shell powder, or mixtures thereof can be blended.

Lightfasteners include bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, bis (1,2,2,6,6-pentamethyl-4-piperidyl) sebacate, and bis (1-octyloxy). -2,2,6,6-tetramethyl-4-piperidyl) sebacate, 2- (3,5-di-t-butyl-4-hydroxyphenyl) -2-n-butyl-bis (2,2,6) , 6-Tetramethyl-4-piperidyl) malonate, 2- (3,5-di-t-butyl-4-hydroxyphenyl) -2-n-butyl-bis (1,2,2,6,6-pentamethyl) -4-piperidyl) malonate, 2- (3,5-di-t-butyl-4-hydroxybenzyl) -2-n-butyl-bis (2,2,6,6-tetramethyl-4-piperidyl) malonate , 2- (3,5-di-t-butyl-4-hydroxybenzyl) -2-n-butyl-bis (1,2,2,6,6-pentamethyl-4-piperidyl) malonate, tetrakis (2, 2,6,6-tetramethyl-4-piperidyl) -1,2,3,4-butanetetracarboxylate, tetrakis (1,2,2,6,6-pentamethyl-4-piperidyl) -1,2, 3,4-Butanetetracarboxylate, mixed (2,2,6,6-tetramethyl-4-piperidyl / tridecyl) -1,2,3,4-butanetetracarboxylate, mixed (1,2,3 2,6,6-Pentamethyl-4-piperidyl / tridecyl) -1,2,3,4-butanetetracarboxylate, mixed {2,2,6,6-tetramethyl-4-piperidyl / β, β, β', β'-tetramethyl-3,9- [2,4,8,10-tetraoxaspiro [5.5] undecane] diethyl} -1,2,3,4-butanetetracarboxylate, mixed {1,2,2,6,6-pentamethyl-4-piperidyl / β, β, β', β'-tetramethyl-3,9- [2,4,8,10-tetraoxaspiro [5.5] ] Undecane] diethyl} -1,2,3,4-butanetetracarboxylate, 1,2-bis (3-oxo-2,2,6,6-tetramethyl-4-piperidyl) ethane, 1- (3) , 5-di-t-butyl-4-hydroxyphenyl) -1,1-bis (2,2,6,6-tetramethyl-4-piperidyloxycarbonyl) pentane, poly [1-oxyethylene (2,2) , 6,6-tetramethyl-1,4-piperidyl) oxysuccinyl], po Li [2- (1,1,4-trimethylbutylimino) -4,6-triazindiyl- (2,2,6,6-tetramethyl-4-piperidyl) iminohexamethylene- (2,2,6) 6-Tetramethyl-4-piperidyl) imino], N, N'-bis (3-aminopropyl) ethylenediamine-2,4-bis [N-butyl-N- (2,2,6,6-tetramethyl-) 4-piperidyl) amino] -6-chloro-1,3,5-triazine condensate and its N-methyl compound, succinic acid and 1- (2-hydroxyethyl) -4-hydroxy-2,2,6,6 -Polycondensate with tetramethylpiperidin, poly [{6-((1,1,3,3-tetramethylbutyl) amino-1,3,5-triazine 2,4-diyl} {(2,2,2, 6,6-Tetramethyl-4-piperidyl) imino} Hexamethylene {((2,2,6,6-tetramethyl-4-piperidyl) imino}], olefin (C20-C24), maleic anhydride, 4- Amino-2,2,6,6-tetramethylpiperidin copolymer and the like can be mentioned.

Further, the thermoplastic resin that can be used for the agricultural film of the present invention may contain an inorganic filler. The content of the inorganic filler is preferably 0.05 to 10 parts by mass, more preferably 0.1 to 9.5 parts by mass, and further preferably 0.1 to 9.5 parts by mass with respect to 100 parts by mass of the total mass of the resin component of the agricultural film. It is 0.5 to 9.0 parts by mass. By containing the inorganic filler as described above, when producing an agricultural film, the resin component of the agricultural film can have an appropriate viscosity, and better moldability can be obtained.

Inorganic fillers that can be used in the present invention include silica, mica, talc, titanium oxide, calcium carbonate, diatomaceous soil, allophen, bentonite, potassium titanate, zeolite, sepiolite, smectite, kaolin, kaolinite, glass, limestone, etc. Carbon, kaolinite, calcined pearlite, silicates such as calcium silicate and sodium silicate, hydroxides such as aluminum oxide, magnesium carbonate, calcium hydroxide, ferric carbonate, zinc oxide, iron oxide, aluminum phosphate and barium sulfate Etc., and one of these may be used alone, or two or more thereof may be mixed and used.

Further, the agricultural biodegradable film in which the biodegradable resin is used as the thermoplastic resin of the agricultural film of the present invention is biodegradable for agricultural use after use by using a pigment containing no copper component as the pigment. It can be particularly preferably used as a method for preventing the copper component from remaining in the soil even when the sex film is decomposed.

The thickness of the agricultural biodegradable film of the present invention is preferably 5 μm to 50 μm, more preferably 5 μm to 40 μm, further preferably 5 μm to 35 μm, and particularly preferably 5 μm to 30 μm. By setting the thickness of the biodegradable film to 5 μm or more, the molding of the film can be made more stable, and it is possible to prevent the strength from becoming insufficient when used for stretching work or the like. Further, by setting the film thickness to 50 μm or less, the average value (A) of the total light transmittance in the wavelength range of 640 to 690 nm and the average value of the total light transmittance in the wavelength range of 400 to 700 nm specified in the present invention. The value of (B) can be made more preferable.

Further, on the surface of the agricultural film of the present invention, printing (marking) such as a product name and a production lot can be performed. The color used for the printing is preferably a color that is easily identifiable with respect to the color of the agricultural film. Further, as the pigment used for the printing, it is preferable to use a pigment that does not contain a copper component.

As the method for kneading the thermoplastic resin in producing the agricultural film of the present invention, a general method can be used as the kneading method for the resin composition. Specifically, pellets, powders, solid debris, etc. are dry-mixed with a Henschel mixer or ribbon mixer, and used as a known melt-kneader such as a single-screw or twin-screw extruder, a Banbury mixer, a kneader, or a mixing roll. It can be supplied and melt-kneaded.

As a method for forming a film from a thermoplastic resin composition, an extrusion molding method in which a film extruded by a T-die using an extruder is cooled and solidified by a cast roll, or a method of forming a film by an inflation molding machine is suitable.

Examples of the present invention will be described below, but the present invention is not limited to these examples.

[Evaluation method]
(1) Measurement method of total light transmittance (A), (B), (D) (unit:%)
Using Shimadzu Corporation (UV-2450), the total light transmittance of the obtained film in the measurement wavelength range of 200 to 900 nm was measured, and the measurement data for each 0.5 nm was taken out by the average value calculation method, and 640. The average value of the total light transmittance in each wavelength range of ~ 690 nm (A), 400 to 700 nm (B), and 420 to 470 nm (D) was calculated.

(2) Measurement method of total light transmittance (C) (unit:%)
Using an infrared spectrophotometer (270-30 type) manufactured by Hitachi, Ltd., the total light transmittance of the obtained film at 2.5 to 25 μm was measured, and from the obtained chart, every 1 μm from 5 μm to 25 μm. The average value (C) of the total light transmittance in the wavelength range of 5 to 25 μm was calculated by reading the transmittance of.

(3) Evaluation of weed control effect A film (mulch film) obtained from September 2014 was spread on a farmland in Matsusaka City, Mie Prefecture, and a black film (comparison) was applied to the weed growth control effect about two months later. The evaluation of each film was evaluated according to the following criteria based on the overgrowth state of weeds when Example 2) was used.
◎: Equivalent weed overgrowth ○: Weeds overgrown slightly ×: Weeds overgrown

[Raw materials used]
-Aliphatic aromatic polyester (A): Made by BASF, product name "Ecoflex"
-Alphatic polyester (B-1): Mitsubishi Chemical Corporation product name "GSPla FZ91PN"
-Alphatic polyester (B-2): Mitsubishi Chemical Corporation product name "GSPla FD99WN"
-Inorganic filler (talc): Made by Japan Mistron Co., Ltd. Product name "MISTRON850JS"
[Pigments used]
・ Pigment Yellow 138
・ Carbon Black Pigment Blue 27
[Examples 1 and 2 and Comparative Examples 1 and 2]
As for the pigment and the inorganic filler, a masterbatch was prepared by melting and kneading the mixture with the aliphatic polyester (B-1) in a fixed amount using a twin-screw extruder, and each is shown in Table 1. A film having a thickness of 18 μm was formed by dry blending in a pellet state, setting the cylinder and die temperatures to the melting temperature of the aliphatic aromatic polyester + 40 ° C., and using an inflation molding machine manufactured by Modern Co., Ltd.

The obtained film was measured for the average value of the total light transmittance in each wavelength range by the above test method, and the obtained results are shown in Table 1.

From Table 1, in the agricultural films of Examples 1 and 2, the average value (A) of the total light transmittance in the wavelength range of 640 to 690 nm and the average value of the total light transmittance in the wavelength range of 400 to 700 nm (B). ) Is the range specified in the present invention, and it can be seen that it has a function of raising the soil temperature while suppressing the growth of weeds.

On the other hand, the transparent agricultural film of Comparative Example 1 had a high average value (A) of the total light transmittance in the wavelength range of 640 to 690 nm, and it was found that weeds were easy to grow. The black agricultural film has a low average value (A) of total light transmittance in the wavelength range of 640 to 690 nm and can suppress the growth of weeds, but the average value of total light transmittance in the wavelength range of 400 to 700 nm (A). Since B) is also low, it can be seen that the soil temperature raising function is inferior.

Therefore, according to the present invention, it is possible to provide an agricultural film and an agricultural biodegradable film which are excellent in raising the soil temperature and suppressing the growth of weeds and do not leave a copper component in the soil.

Claims (3)

Containing pigment containing no copper component, and the average value of the total light transmittance in the wavelength region of 640~690nm (A) is 40% or less, the average value of total light transmittance of the wavelength range of 400 to 700 nm (B) There 25% or more, and, Ri average (D) is der 45% or less of the total light transmittance in the wavelength region of 420 to 470 nm,
The pigment contains at least a blue pigment and pigment yellow, and contains 20 to 80 parts by mass of pigment yellow with respect to the total mass of the pigment components.
An agricultural film characterized by containing a biodegradable resin as a resin component. The agricultural film according to claim 1 , wherein the average value (C) of the total light transmittance in the wavelength range of 5 to 25 μm is 55% or less. The agricultural film according to claim 2 , wherein the thickness is 50 μm or less.