JP6902688B1 - Colored resin compositions for agricultural films, and agricultural films - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an environmentally friendly agricultural film, which is not only biodegradable but also does not leave copper in the soil after biodegradation, and is excellent in moldability, storage stability and stretchability. A resin composition and an agricultural film using the same are provided. SOLUTION: The organic pigment B contains a biodegradable resin A and an organic pigment B, and the organic pigment B contains a blue pigment B1x which is at least one of a blue pigment having an anthraquinone skeleton and a metal-free phthalocyanine blue pigment. It is solved by a colored resin composition for an agricultural film. [Selection diagram] None

Description

The present invention relates to a colored resin composition for an agricultural film and an agricultural film using the same.

Since plastic is easy to mold, it is used in a wide range of fields such as electrical and electronic equipment parts, automobile parts, medical parts, food containers, etc. Is actively colored. Especially in the field of agricultural films, colored molded products are distributed for the purpose of raising soil temperature, keeping heat, and controlling pests.

This agricultural film includes a colorless transparent film and a colored film such as a black film, a silver film, or a green film, and these are properly used according to the required functions.

The colorless transparent film has a weak light-shielding effect, so that the soil temperature rises, which is advantageous for promoting the growth of crops. However, it has no weed control function, and overgrown weeds cause film damage, resulting in a decrease in the effect of the film. In addition, weeding in the film is required, which requires a great deal of labor.

On the other hand, the black film, the silver film, and the green film, which are colored films, have an excellent weed control effect due to the light-shielding action. Among them, green film is widely used because it can be expected to have a function of raising soil temperature in addition to a weed control effect.

As a colorant used for such a green film, a technique of combining a green pigment such as copper phthalocyanine green or a blue pigment such as copper phthalocyanine blue with another pigment is known in Patent Documents 1 and 2. .. However, the pigments used in these technologies contain copper as a heavy metal, and the copper component is regarded as one of the substances that inhibit the growth of rice, and standard values are set to form agricultural films. It is a problem to use it as a component of.

Further, Patent Document 3 describes an agricultural film using Pigment Blue 27 and Pigment Yellow 138. Pigment Blue 27 used here is an inorganic pigment and has low coloring power, so that it is necessary to use a large amount of pigment, and since the inorganic pigment has poor saturation, a large amount of pigment is used. As a result, the transparency is also reduced. Therefore, there is a problem that light is not transmitted due to this and the function of raising the soil temperature is lowered.

In addition, as a solution to reduce the recent waste problem and the work of collecting agricultural films, there are agricultural films using biodegradable materials, which do not need to be collected and can be decomposed in the soil after use. is there.
In such a biodegradable agricultural film, when a pigment containing a copper component as described above is used, in addition to the problem that the copper component in the pigment remains in the soil, a pigment having a lower crystallization effect. Then, the slow crystallization rate greatly changes the moldability, and the non-crystalline region of the resin has a faster hydrolysis rate than the crystalline region, so that a resin that is easily hydrolyzed, such as a biodegradable resin. When is used, the storage stability of the product becomes a problem.

In addition, there is a problem that the agricultural film is broken if the agricultural film does not have a certain degree of flexibility during the stretching work, which covers the soil using an agricultural machine such as a film spreading machine, and is environmentally friendly. However, at present, it is difficult to satisfy all of such moldability, storage stability, and stretchability.

Japanese Unexamined Patent Publication No. 3-155717 Japanese Unexamined Patent Publication No. 2012-95568 Japanese Unexamined Patent Publication No. 2016-152787

Therefore, the problem to be solved by the present invention is an environmentally friendly agricultural film, which is not only biodegradable but also does not leave copper in the soil after biodegradation, and has formability, storage stability, and so on. An object of the present invention is to provide a colored resin composition for an agricultural film having excellent stretchability and an agricultural film using the same.

The present inventors have reached the present invention as a result of diligent studies in order to solve the above problems.
That is, the present invention includes a biodegradable resin (A) and an organic pigment (B), and the organic pigment (B) contains at least one of a blue pigment having an anthraquinone skeleton and a metal-free phthalocyanine blue pigment. The present invention relates to a colored resin composition for an agricultural film.

According to the present invention, it is an environmentally friendly agricultural film, and it is a colored resin composition for agricultural films that is not only biodegradable but also has excellent moldability and storage stability without leaving copper in the soil after biodegradation. It becomes possible to provide goods and agricultural films using them.

Hereinafter, the present invention will be described in detail.
In the present specification, a blue pigment (B1x) which is at least one of a blue pigment having an anthraquinone skeleton and a metal-free phthalocyanine blue pigment may be abbreviated as a blue pigment (B1x).
As for the average particle size of the organic pigment (B), 100 particles were randomly observed using a transmission electron microscope, and the distance between the two most distant points on the outer shape of each particle was measured as a micron on the screen. It is a value obtained by measuring based on the length of the marker and averaging it.

<< Colored resin composition for agricultural films >>
The colored resin composition for agricultural films in the present invention contains a biodegradable resin (A) and an organic pigment (B), and the organic pigment (B) is a blue pigment having an anthraquinone skeleton and a metal-free phthalocyanine blue pigment. Includes at least one of the blue pigments (B1x).
Such a colored resin composition for agricultural films not only enables biodegradation, but also makes it possible to produce an environment-friendly agricultural film that does not leave copper in the soil after biodegradation. Moreover, it is possible to obtain a resin composition having excellent moldability and storage stability.
From the viewpoint of environmental friendliness, the organic pigment (B) preferably does not contain an organic pigment having copper, and when it does not contain an organic pigment having a chlorine atom, the content of not only copper but also the chlorine atom is conventionally high. It can be significantly reduced and is desirable as an environment-friendly type.
The upper limit of the copper content in the environmentally friendly agricultural film is preferably 37.5 ppm.

Further, the resin composition of the present invention preferably contains a yellow pigment (B2) in addition to the blue pigment (B1x) as the organic pigment (B), and is preferably used as a colored resin composition for a green agricultural film. By using a green film, it is possible to obtain an agricultural film having an excellent function of raising soil temperature in addition to a weed control effect.

As a colorant, an inorganic pigment can also be used as long as it does not impair the effects of the present invention.
Specifically, as the other colorant, a black inorganic pigment such as carbon black can be preferably used.

The decomposition process of agricultural film can be roughly divided into two.
The first step is to reduce the molecular weight of the film by hydrolysis or oxidative decomposition.
Then, in the second step, microorganisms in the soil decompose the low molecular weight film pieces.
As for the role of agricultural film, hydrolysis control in the first stage is important because the molecular weight is reduced even during the storage period of the film or while the film is used. Crystallinity of the resin can be mentioned as a factor of hydrolysis. Since hydrolysis is more likely to proceed in the amorphous region than in the crystalline region, it is possible to suppress hydrolysis by increasing the crystallinity. When the particle size is relatively large, such as an inorganic pigment, the crystallinity effect of the pigment is weak, so improvement in crystallinity cannot be expected. On the other hand, in general, an organic pigment having a small particle size has a strong nucleation effect due to the pigment, so that the crystallinity is improved and a hydrolysis suppressing effect can be obtained.
However, even if it is a blue organic pigment that does not have copper, if the planar structure is broken, such as a blue pigment having a triphenylmethane skeleton, the crystallinity is low and the nucleation effect is low. ..
On the other hand, the colored resin composition for agricultural films in the present invention is at least one of a blue pigment having an anthraquinone skeleton having a planar structure, high crystallinity and a high nucleation effect, and a metal-free phthalocyanine blue pigment. By using the blue pigment (B1x), not only does copper not remain in the soil after biodegradation, but also the crystallization effect of the blue pigment (B1x) improves crystallinity and suppresses hydrolysis. Can be done. Further, when an agricultural film is produced from a colored resin composition for an agricultural film, a large amount of heat history is required. By using the blue pigment (B1x), the effect of suppressing hydrolysis is greater than when other pigments are used due to the action of the nucleation effect. As a result, not only the colored resin composition but also the storage stability of the agricultural film is excellent, and the moldability is improved by improving the crystallization rate, so that it is possible to provide the agricultural film with improved productivity. Become.

The colored resin composition for agricultural films of the present invention is a masterbatch used by diluting with a molding resin at the time of molding, or a compound in which a required amount of an organic pigment is mixed with a biodegradable resin and molded as it is without being diluted with a molding resin. It can be used without any problem in any form.

<Biodegradable resin (A)>
The biodegradable resin (A) of the present invention will be described.
The biodegradable resin (A) in the present invention is used as an agricultural film and then decomposed by the action of various microorganisms existing in the surroundings and water in the soil. The biodegradable resin (A) that can be used in the present invention is not particularly limited, and a generally available biodegradable resin can be used. For example, polycaprolactone, polyvinyl alcohol, polyamide, cellulose ester, lactic acid polyester resin, aliphatic polyester resin, aliphatic aromatic polyester resin and the like can be mentioned. These biodegradable resins may be used alone or in combination of two or more.
Among these, an aliphatic polyester resin or an aliphatic aromatic polyester resin is preferable in consideration of the workability of film stretching.
When a biodegradable resin is used in combination, the blending amount of the aliphatic polyester resin or the aliphatic aromatic polyester resin is 40 to 99.8% by mass in 100% by mass of the biodegradable resin (A). Is preferable, and more preferably 50% by mass or more, still more preferably 60% by mass or more, which is preferable from the viewpoint of workability of stretching the film.

Examples of the aliphatic polyester resin include an aliphatic polyester obtained by a polycondensation reaction between an aliphatic diol and an aliphatic dicarboxylic acid. Examples of the aliphatic diol include ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, 1,6-hexanediol, 1,4-cyclohexanediol, and 1,4-cyclohexanedi. Examples include methanol. These may be used alone or as a mixture thereof. Of these, it is preferable to use 1,4-butanediol. Examples of the aliphatic dicarboxylic acid include oxalic acid, succinic acid, glutanoic acid, adipic acid, sebacic acid, suberic acid, and dodecanedioic acid, and acid anhydrides which are derivatives of these may be used. Of these, succinic acid or succinic anhydride, or a mixture of these and adipic acid is preferable.
Specifically, polybutylene succinate (PBS) obtained from 1,4-butanediol and succinic acid (for example, BioPBS manufactured by PPT MCC Biochem), polybutylene succinate adipate (PBSA) obtained by copolymerizing adipic acid with PBS, etc. Can be mentioned.

Examples of the aliphatic aromatic polyester resin include copolymers containing an aliphatic dicarboxylic acid unit, an aromatic dicarboxylic acid unit, and a chain aliphatic and / or alicyclic diol unit. The diol component that gives the diol unit usually has 2 to 10 carbon atoms, and examples thereof include ethylene glycol, 1,3-propanediol, 1,4-butanediol, and 1,4-cyclohexanedimethanol. .. Of these, diols having 2 to 4 carbon atoms are preferable, ethylene glycol and 1,4-butanediol are preferable, and 1,4-butanediol is even more preferable. The dicarboxylic acid component that gives the dicarboxylic acid unit usually has 2 to 10 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 that gives an aromatic dicarboxylic acid unit include terephthalic acid, isophthalic acid, naphthalenedicarboxylic acid and the like. Among them, terephthalic acid and isophthalic acid are preferable, and terephthalic acid is more preferable.
Specific examples thereof include PBAT (for example, Ecoflex manufactured by BAS), which is a copolymer of 1,4-butanediol, adipic acid and terephthalic acid.

Others include, for example, poly (3-hydroxy alkanoate) of an aliphatic polyester copolymer obtained from hydroxy-alkanoic acid and polyvalent carboxylic acid (among others, poly (3-hydroxybutyrate-co-3-hydroxyhexa). Noate) (PHBH) (for example, Aonilex manufactured by Kaneka), polylactic acid (PLA) (for example, REVODE manufactured by Kaisei Biological Materials Co., Ltd., Ingeo manufactured by Nature Works).

The blending amount of the biodegradable resin (A) is preferably 40 to 99.8% by mass in 100% by mass of the resin composition. When the resin composition is used as a masterbatch, the blending amount of the biodegradable resin (A) is more preferably 40 to 98% by mass. When the resin composition is used as a compound, the blending amount of the biodegradable resin (A) is more preferably 80 to 99.8% by mass, further preferably 94 to 99.4% by mass.

<Organic pigment (B)>
The organic pigment (B) of the present invention will be described.
By coloring the green resin composition of the present invention with the organic pigment (B), it is possible to form an agricultural film having an excellent heat-shielding effect.
The organic pigment (B) of the present invention contains a blue pigment (B1x) which is at least one of a blue pigment having an anthraquinone skeleton and a metal-free phthalocyanine blue pigment, whereby a colored agricultural film can be obtained.
Among them, it is preferable to use a blue pigment (B1x) and a yellow pigment (B2) to form a green agricultural film because not only the heat shielding effect is excellent but also the weed control effect can be achieved.
The organic pigment (B) may contain other known organic pigments in addition to the blue pigment (B1x) and the yellow pigment (B2) if necessary, but from the viewpoint of environmental friendliness, the organic pigment containing copper may be contained. It is preferable that the pigment is substantially not contained, and further, it is preferable that the organic pigment having a chlorine atom is not contained because it is more excellent as an environment-friendly agricultural film.

The amount of the organic pigment containing copper in 100% by mass of the organic pigment (B) is preferably 10% by mass or less, more preferably 5% by mass or less, and further preferably 1% by mass or less.
Further, in 100% by mass of the organic pigment (B), the amount of the organic pigment having a chlorine atom is preferably 10% by mass or less, more preferably 5% by mass or less, and further preferably 1% by mass or less. ..

[Blue pigment (B1)]
The organic pigment (B) of the present invention includes a blue pigment (B1x) which is at least one of a blue pigment having an anthraquinone skeleton and a metal-free phthalocyanine blue pigment.

(Blue pigment (B1x))
The blue pigment (B1x) is at least one of a blue pigment having an anthraquinone skeleton and a metal-free phthalocyanine blue pigment.
By using the blue pigment (B1x), not only copper and chlorine do not remain in the soil after biodegradation, but also the crystallization temperature rises due to the nucleation effect peculiar to the organic pigment, and the moldability is excellent. .. In addition, the improved crystallinity of the agricultural film also improves the moldability and suppresses hydrolysis.

Specific examples of the blue pigment having an anthraquinone skeleton include Pigment Blue 60 and Pigment Blue 64. Among them, Pigment Blue 60 (for example, Lionogen Blue R manufactured by Toyo Color Co., Ltd.) is preferable because it is more excellent as an environmentally friendly agricultural film because it does not contain an organic pigment having a chlorine atom.
Examples of the metal-free phthalocyanine blue pigment include Pigment Blue 16 (for example, Heliogen Blue L7460 manufactured by BASF Co., Ltd.) and the like.

The average particle size of the blue pigment (B1x) is preferably 10 to 500 nm, more preferably 10 to 200 nm. When the average particle size is in the above range, the nucleation effect is improved, the crystallization rate is improved, and an agricultural film having good crystallinity and moldability can be provided.

The blending amount of the blue pigment (B1x) is preferably 0.1 to 30% by mass in 100% by mass of the colored resin composition. When the colored resin composition is a masterbatch, the blending amount of the blue pigment (B1x) is preferably 1 to 30% by mass. When the blending amount of the blue pigment (B1x) is within the above range, both the dispersibility of the pigment and the processability of the masterbatch can be achieved. When the colored resin composition is a compound, 0.1 to 10% by mass is preferable, and 0.3 to 3% by mass is more preferable.

The blending amount of the blue pigment (B1x) in 100% by mass of the blue pigment (B1) is preferably 70 to 100% by mass, more preferably 80% by mass or more, and further preferably 90% by mass or more. is there.
Within the above range, the crystallinity of the blue pigment (B1x) can be improved and hydrolysis can be suppressed, which is preferable.

[Yellow pigment (B2)]
The colored resin composition of the present invention can further use a yellow pigment (B2) to prepare a resin composition for a green agricultural film.
The yellow pigment (B2) preferably does not contain a copper-free yellow pigment, and more preferably does not contain a yellow pigment having a chlorine atom in terms of environmental friendliness.
When a large amount of organic pigment having a chlorine atom is used, chlorine remains in the soil after the agricultural film is decomposed in the soil. As a result, a high concentration of chlorine remains in the soil, which affects the germination and seedlings of plants, which may cause germination delay, decrease in germination rate, and poor growth of seedlings.

Examples of the yellow pigment (B2) include Pigment Yellow 1, 3, 12, 13, 14, 16, 17, 55, 74, 81, 83, 87, 93, 94, 95, 97, 98, 109, 110, 116, 120, 127, 128, 138, 139, 154, 155, 167, 168, 169, 173, 180, 181, 183, or 191 and the like.
Among these, Pigment Yellow 1, 74, 120, 155, 169, 173, 180, or 181 which is a yellow pigment having no chlorine atom is preferable because it is excellent as an environment-friendly agricultural film. Further, Pigment Yellow 155, 180, or 181 is particularly preferable from the viewpoint of coloring power, weather resistance, and the like.

The average particle size of the yellow pigment (B2) is preferably 10 to 500 nm, more preferably 10 to 200 nm. When the average particle size is in the above range, the nucleation effect is improved, the crystallization rate is improved, and an agricultural film having good crystallinity and moldability can be provided.

The blending ratio of the blue pigment (B1x) and the yellow pigment (B2) is preferably in the range of 0.03 to 5 for the blue pigment (B1x) / yellow pigment (B2), and further, the blue pigment (B1x) / yellow pigment. The range of (B2) of 0.1 to 4 is more preferable. By setting the blending ratio, it is possible to obtain an environment-friendly green agricultural film having both a weed control function and a soil temperature rise function.
Within the above range, the crystallinity of the blue pigment (B1x) can be improved and hydrolysis can be suppressed, which is preferable.

<Other additives>
Other additives can be added to the colored resin composition of the present invention, if necessary. Other additives include, for example, dispersants, lubricants (higher fatty acid metal salts, waxes, etc.), hydrotalcites, surfactants, antistatic agents, flame retardants, antioxidants, ultraviolet absorbers, etc. Additives such as fillers can be included. The selection of other arbitrary components and the amount used thereof are not particularly limited as long as the problems of the present invention can be solved.

Examples of the dispersant for dispersing the organic pigment (B) include fatty acid metal salts. The fatty acid component of the fatty acid metal salt is a chain carboxylic acid having a carboxylic acid and usually having 6 to 30 carbon atoms, which may be linear or branched, or may have only a saturated bond or an unsaturated bond. Good. Examples of fatty acids include caproic acid, caprylic acid, caproic acid, lauric acid, myristic acid, palmitic acid, palmitic acid, stearic acid, behenic acid, oleic acid, erucic acid, linoleic acid, montanic acid and the like.
As the metal atom, 1A, 2A, 2B and 3B atoms are preferable, and 1A and 2A atoms are more preferable. Examples include sodium, potassium, calcium, magnesium, barium and the like.

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

<Manufacturing method of colored resin composition for agricultural film>
The colored resin composition for agricultural films of the present invention can be obtained by kneading an organic pigment at a temperature at which the biodegradable resin (A) melts. The method for producing the colored resin composition is, for example, adding a biodegradable resin (A), an organic pigment (B), and various additives as necessary, and adding a kneader, a roll mill, a super mixer, a high speed mixer, and a ball mill. , Sand mill, attritor, batch kneader such as Banbury mixer, single-screw extruder, twin-screw extruder, rotor-type twin-screw kneader, etc. It can be a bead-shaped resin composition. Since the kneading force is strong and the subsequent molding process is easy, it is preferable to make pellets by a single-screw extruder or a twin-screw extruder.

The colored resin composition for agricultural films of the present invention is obtained by melt-kneading a biodegradable resin (A), a blue pigment (B1x), and a yellow pigment (B2) together, if necessary, as a green resin composition. A blue resin composition obtained by fusing and kneading a biodegradable resin (A) and a blue pigment (B1x) is once obtained, and then, at the time of molding, it is combined with a resin composition such as a yellow resin composition. It may be kneaded to form a green agricultural film.
Among them, the biodegradable resin (A), the blue pigment (B1x), and the yellow pigment (B2) are melt-kneaded together to form a green resin composition from the viewpoint of excellent film productivity and color unevenness. The method of forming a green agricultural film is preferable.

《Agricultural film》
The agricultural film of the present invention will be described.
The agricultural film is formed from the colored resin composition of the present invention. As a method for molding a film from the colored 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, a method of molding by an inflation molding machine, or the like is suitable.

As a method for producing an agricultural film of the present invention, the colored resin composition may be used in either the form of a masterbatch or a compound.
In the case of a masterbatch, after the masterbatch is produced, the same biodegradable resin (A) used for producing the masterbatch is used as the main resin of the agricultural film, for example, as the diluting resin, and the masterbatch is mixed for agriculture. A film can be made. The amount of the masterbatch blended is preferably 1 to 50 parts by mass, more preferably 1 to 20 parts by mass, based on 100 parts by mass of the biodegradable resin (A) which is the main resin.
The biodegradable resin (A) used as the diluting resin at this time may be the same as that used in the production of the masterbatch, or may be different, but the same biodegradable resin is used. It is preferable because the resin composition and the resin have excellent compatibility.
In the case of the compound, after the compound is produced, the compound can be used as it is to produce an agricultural film by the above method.

The thickness of the agricultural film of the present invention is preferably 5 to 50 μm, more preferably 5 to 35 μm. By setting the thickness of the agricultural film within the above range, more stable film moldability, light-shielding property, and strength required for use in stretching work can be satisfied.

Hereinafter, the present invention will be described in more detail based on Examples, but the present invention is not limited to Examples. In the examples, parts and% represent parts by mass and% by mass, respectively, unless otherwise specified.
In addition, the compounding amount in the table is a mass part. The blanks in the table indicate that they are not mixed.
The method for measuring the average particle size of the organic pigment is as follows.

<Measurement of average particle size>
JEOL's transmission electron microscope JEM-1010 was used to observe pigment particles, 100 particles were randomly observed, and the distance between the two most distant points on the outer shape of each particle was determined by the micron marker on the screen. It was measured based on the length and averaged.

Subsequently, the materials used for the colored resin composition are listed below.
<Biodegradable resin>
A-1: Ecoflex (aliphatic aromatic polyester resin manufactured by BASF Co., Ltd .: PBAT resin)
A-2: BioPBS FZ71 (PTT MCC Biochem's aliphatic polyester resin: PBS resin)
A-3: PLA6201D (Lactic acid polyester resin manufactured by Nature Works: PLA resin)

<Organic pigment>
[Blue pigment (B1)]
(Blue pigment (B1x))
B1x-1: Lionogen Blue R (Made by Toyo Color Co., Ltd. Average particle size: 80 nm: Blue pigment having an anthraquinone skeleton)
B1x-2: Heliogen Blue L7460 (Average particle size manufactured by BASF Co., Ltd .: 200 nm: Metal-free phthalocyanine blue pigment)
B1x-3: Blue pigment having an anthraquinone skeleton of Production Example 1 below (average particle size: 500 nm: blue pigment having an anthraquinone skeleton)

(Production Example 1; Blue Pigment (B1x-3))
C. I. Weigh 10 parts of Pigment Blue 60 crude pigment, 100 parts of dimethyl sulfoxide containing 10% ethyl alcohol, and 5 parts of potassium-t-butoxide into a flask, and stir in a nitrogen atmosphere at 35 ° C. for 3 hours to coarsely slen. The pigment dissolved to give a turquoise solution. 100 parts of methyl alcohol at 35 ° C. was added to this solution under stirring at 35 ° C., and the solution was stirred while maintaining a uniform slurry. After filtering the slurry, the residue was washed with water at 60 ° C. and then dried to obtain a blue pigment having a blue anthraquinone skeleton. The average particle size of this pigment was measured and found to be 500 nm.

(Other blue pigments)
B1y-1: Lionol Blue CB7801 (Made by Toyo Color Co., Ltd. Average particle size: 50 nm: Copper phthalocyanine blue pigment containing copper)
B1y-2: Lionol Green 8930 (Made by Toyo Color Co., Ltd. Average particle size: 50 nm: Copper phthalocyanine-based green pigment Copper, containing chlorine atom)
B1y-3: Fanal Blue D6390 (Average particle size manufactured by BASF Co., Ltd .: 70 nm: Triphenylmethane-based blue pigment copper, no chlorine atom)

(Yellow pigment (B2))
B2-1: PV First Yellow HG (Clariant average particle size: 100-180 nm: imidazolone-based yellow pigment without chlorine atom)
B2-2: Paliotor Yellow K0961 (B.A.S.F., Inc. average particle size: 200 to 500 nm: quinophthalone-based yellow pigment containing chlorine atom)

<Inorganic pigment>
D-1: MILORI BLUE FX-6940 (Dainichiseika Co., Ltd. average particle size: 50 to 200 nm: blue inorganic pigment)
D-2: Ultramarine Blue CM241 (Made by Benatar, average particle size: 500 nm: blue inorganic pigment)

(Manufacturing of colored resin fat composition)
[Example 1]
(Manufacturing of colored resin composition (compound))
98.3 parts by mass of (A-1) as biodegradable resin (A), 1 part by mass of (b1-1) as blue pigment (B1x), 0.7 parts by mass of (B2-1) as yellow pigment (B2) Was mixed and extruded at 230 ° C. with a twin-screw extruder (manufactured by Japan Steel Works, Ltd.) to obtain a colored resin composition by granulation.

(Manufacturing of agricultural film)
The obtained colored resin composition was extruded at a temperature of 230 ° C. using a 30 mmΦ inflation extruder (manufactured by Tosoku Seimitsu Kogyo Co., Ltd.) to obtain an agricultural film (thickness 20 μm).

[Examples 2 to 12]
A colored resin composition and an agricultural film were obtained in the same manner as in Example 1 except that the materials and the blending amounts (parts by mass) shown in Tables 1 and 2 were changed.
However, Example 10 is a reference example.

[Examples 13 to 16]
(Manufacturing of colored resin composition (master batch))
Colored resin compositions were obtained in the same manner as in Example 1 except that the materials and the blending amounts (parts by mass) shown in Table 2 were changed.

(Manufacturing of agricultural film)
5 parts by mass of the obtained colored resin composition and 100 parts by mass of the same biodegradable resin used for the colored resin composition were subjected to a temperature of 230 using a 30 mmΦ inflation extruder (manufactured by Tosoku Seimitsu Kogyo Co., Ltd.). Extrusion molding was performed at ° C. to obtain an agricultural film (thickness 20 μm).

[Comparative Example 1]
98.3 parts by mass of (A-1) as the biodegradable resin (A), 1 part by mass of the inorganic pigment (D-1), and 0.7 parts by mass of (B2-1) as the yellow pigment (B) were mixed. It was extruded at 230 ° C. with a twin-screw extruder (manufactured by Japan Steel Works, Ltd.) and granulated to obtain a colored resin composition.

The obtained colored resin composition was extruded at a temperature of 230 ° C. using a 30 mmΦ inflation extruder (manufactured by Tosoku Seimitsu Kogyo Co., Ltd.) to obtain an agricultural film (thickness 20 μm).

[Comparative Examples 2 to 7]
A colored resin composition and an agricultural film were obtained in the same manner as in Comparative Example 1 except that the materials and the blending amounts (parts by mass) shown in Table 3 were changed.

The colored resin compositions and agricultural films obtained in Examples and Comparative Examples were evaluated according to the following criteria. The evaluation results are shown in Table 4.

<Evaluation of hydrolyzability>
As a hydrolyzability evaluation, the terminal carboxyl group increasing concentration of the colored resin composition and the agricultural film was evaluated. The terminal carboxyl group increase concentration is an index indicating the degree of hydrolysis of the polyester resin. It can be said that the lower the concentration of the terminal carboxyl group increase, the more the decomposition of the biodegradable resin is suppressed, and the better the storage stability of the product.
As a method for evaluating hydrolyzability, a colored resin composition or an agricultural film was dissolved in an o-cresol solvent, and a 0.1 mol / L potassium hydroxide ethanol solution was used for measurement by a potential differential titration method. In the evaluation, the difference from the terminal carboxyl group concentration of the biodegradable resin used in the colored resin composition and the agricultural film was taken as the terminal carboxyl group increase concentration. The hydrolyzability was evaluated according to the following criteria.
[Evaluation criteria]
◯: Less than 40 equivalents / ton, which is excellent in practical use.
Δ: 40 equivalents / ton or more, less than 80 equivalents / ton, within the practical range ×: 80 equivalents / ton or more, impractical.

<Environmental evaluation>
As an environmentally friendly evaluation, the materials used for the colored resin composition were evaluated as follows.
[Evaluation criteria]
◎: None of copper and chlorine atoms ○: With chlorine atoms, without copper △: With copper, without chlorine atoms ×: With both copper and chlorine atoms

<Evaluation of moldability>
As a formability evaluation, it was evaluated by the crystallization temperature difference of the agricultural film. The crystallization temperature is an index indicating the temperature at which the crystallization rate becomes the fastest in the cooling process of the molten resin. It can be said that the moldability is excellent because the crystallization rate increases in the process of cooling the molten resin due to the increase in the crystallization temperature. A predetermined amount of agricultural film was placed in an aluminum pan, and the crystallization temperature was measured by a differential scanning calorimeter. For the evaluation, the difference from the crystallization temperature of the biodegradable resin used for the environmentally friendly agricultural film was taken as the crystallization temperature difference.
[Evaluation criteria]
◯: The crystallization temperature difference is +40 degrees or more, which is excellent in practical use.
Δ: The crystallization temperature difference is less than +20 degrees to less than +40 degrees, which is within the practical range.
X: The crystallization temperature difference is less than +20 degrees, which is not practical.

<Evaluation of film stretchability>
As an evaluation of the stretchability of the film, the tensile elongation at break of the agricultural film was evaluated. The tensile elongation at break is an index showing the elongation of the film when the film is broken by the tensile test of the film. It can be said that the higher the elongation rate of the film, the better the stretchability. The prepared film (thickness 20 μm) was punched into a tensile No. 2 dumbbell shape, and the tensile elongation at break was measured using a tensile tester. The expandability was evaluated according to the following criteria.
[Evaluation criteria]
⊚: The tensile elongation at break is 200% or more, which is excellent in practical use.
◯: The tensile elongation at break is 100% or more and less than 200%, which is within the practical range.
Δ: The tensile elongation at break is less than 100%, which is within the practical range, but there is a possibility of partial fracture.

From the above evaluation results, the colored resin composition for agricultural films of the present invention and the agricultural films using the same are environmentally friendly agricultural films, which are not only biodegradable but also in the soil after biodegradation. It was confirmed that it does not leave copper and is excellent in moldability, storage stability, and stretchability.

In addition, because it is a green film, it is an agricultural film that has an excellent function of raising soil temperature in addition to a weed control effect.

Claims (7)

Contains biodegradable resin (A) and organic pigment (B)
The organic pigment (B) is viewed contains a blue pigment and a blue pigment at least either of the metal-free phthalocyanine blue pigment (B1x) and yellow pigment (B2) having an anthraquinone skeleton,
The average particle size of the blue pigment (B1x) is 10 to 500 nm.
A colored resin composition for an agricultural film , wherein the blending ratio of the blue pigment (B1x) and the yellow pigment (B2) is 0.03 to 4 for the blue pigment (B1x) / yellow pigment (B2). The colored resin composition for an agricultural film according to claim 1, wherein the average particle size of the yellow pigment (B2) is 10 to 500 nm. The colored resin composition for an agricultural film according to claim 1 or 2, wherein the biodegradable resin (A) contains at least one of an aliphatic polyester resin and an aliphatic aromatic polyester resin. The colored resin composition for an agricultural film according to any one of claims 1 to 3, wherein the blue pigment (B1x) is at least one selected from the group consisting of Pigment Blue 60, Pigment Blue 64, and Pigment Blue 16. Stuff. The colored resin composition for an agricultural film according to any one of claims 1 to 4, wherein the organic pigment (B) does not contain an organic pigment having copper. The colored resin composition for an agricultural film according to any one of claims 1 to 5, wherein the organic pigment (B) does not contain an organic pigment having a chlorine atom. An agricultural film formed from the colored resin composition for an agricultural film according to any one of claims 1 to 6.