JP6800739B2 - Agricultural film - Google Patents

Description

The present invention relates to agricultural films.

Conventionally, in the field of agriculture, when cultivating agricultural crops, vinyl chloride film, polyethylene, ethylene-vinyl acetate copolymer and special film mainly composed of polyolefin resin, etc. are used in order to enhance marketability and productivity. House cultivation and tunnel cultivation are actively carried out, in which useful crops are cultivated by covering them with agricultural films.

In the above-mentioned greenhouse cultivation and the like, a leaf burning phenomenon is known as a high temperature disorder especially in summer. The leaf-burning phenomenon means that when a large amount of direct light enters the house, strong light hits the leaves of the cultivated leaves and the leaves are burnt. As a measure to prevent leaf burning, there is a method of coloring the house with titanium oxide or the like to reduce the amount of direct light rays, but in that case, the total light transmittance is also lowered. When the total light transmittance decreases, the transmission of sunlight into the greenhouse decreases, which has a problem of adversely affecting the cultivation of the crop itself.

In addition, since sunlight is weak in winter, it is necessary to allow sunlight to pass through the house. If the amount of sunlight transmitted through the greenhouse is small in winter, the temperature inside the greenhouse will drop, which has the problem of adversely affecting the cultivation of crops.

As an agricultural film for solving such a problem, at least one layer of the outermost layer and the innermost layer is a mixture consisting of a specific ethylene-vinyl acetate copolymer (A) and a specific low-density polyethylene (B). An agricultural film having a multilayer structure composed of a layer and another olefin resin has been proposed (see Patent Document 1).

Japanese Patent No. 3219319

However, the above-mentioned agricultural film has not been sufficiently studied to solve the above-mentioned problems in summer and winter at the same time. The above-mentioned agricultural film has a problem that when the inside of the house is kept warm in winter, dew condensation occurs due to the moisture in the air in the house, and the sunlight is diffusely reflected and it is difficult for the sunlight to pass through the house.

Further, the surface shape for reducing the direct light rays has not been sufficiently studied even in the summer, and the above-mentioned agricultural film has a problem that leaf burning occurs due to the direct sunlight in the summer.

Therefore, there is a demand for the development of an agricultural film in which the amount of light transmission is suppressed during drying in summer and the amount of light transmission is large during dew condensation in winter.

The present invention has been made in view of the above problems, and the amount of light transmission is suppressed during drying in summer, the amount of light transmission can be suppressed during leaf burning of cultivated plants, and the amount of light transmission during dew condensation in winter. It is an object of the present invention to provide an agricultural film through which sunlight is sufficiently transmitted even in winter when sunlight is weak.

As a result of diligent research to achieve the above object, the present inventors have obtained an arithmetic average roughness Ra of the surface of an agricultural film having at least layer A measured in accordance with JIS B0601: 2013. It has been found that the above object can be achieved by the agricultural film having a thickness of 0.1 to 3.0 μm and containing a surfactant, and the present invention has been completed.

That is, the present invention relates to the following agricultural films.
1. 1. Agricultural film with at least layer A
The surface of the layer A has an arithmetic mean roughness Ra of 0.1 to 3.0 μm measured in accordance with JIS B0601: 2013, and contains a surfactant.
Agricultural film characterized by that.
2. 2. Item 2. The agricultural film according to Item 1, wherein the layer A contains two or more types of polyolefin resins having different melt flow rates.
3. 3. Item 2. The agricultural film according to Item 2, wherein the polyolefin-based resin is at least one selected from the group consisting of an ethylene-vinyl acetate copolymer, low-density polyethylene, and linear low-density polyethylene.
4. Item 3. The agricultural film according to any one of Items 1 to 3, wherein the surfactant is at least one selected from the group consisting of glycerin fatty acid ester, polyglycerin fatty acid ester and sorbitan fatty acid ester.
5. Item 4. The agricultural film according to any one of Items 1 to 4, wherein the difference (Hzd-Hzw) between the haze value (Hzd) at the time of drying and the haze value (Hzw) at the time of dew condensation is 10% or more.
6. Item 5. The agricultural film according to Item 5, wherein the haze value (Hzd) at the time of drying is 20 to 50%.
7. Item 5. The agricultural film according to Item 5 or 6, wherein the haze value (Hzw) at the time of dew condensation is less than 20%.
8. Item 2. The agricultural film according to any one of Items 1 to 7, wherein the layer A does not contain inorganic particles.
9. At least the A layer, B layer and C layer are provided in this order.
The B layer is composed of a single layer or a plurality of layers containing a polyolefin resin, and at least one layer contains an inorganic heat insulating agent.
The C layer contains a polyolefin resin.
Item 8. The agricultural film according to any one of Items 1 to 8.
10. An agricultural house, an agricultural curtain or an agricultural tunnel having the agricultural film according to any one of Items 1 to 9.

The agricultural film of the present invention has a suppressed amount of light transmission during drying in summer, can suppress leaf burning of cultivated products, has a large amount of light transmission during dew condensation in winter, and has weak sunlight in winter. Even so, since the sunlight is sufficiently transmitted, it can be suitably used for cultivation of agricultural crops.

It is sectional drawing which shows an example of the layer structure of the agricultural film of this invention.

Hereinafter, the agricultural film of the present invention will be described in detail.

The agricultural film of the present invention is an agricultural film having at least an A layer, and the A layer has an arithmetic mean roughness Ra of the surface measured in accordance with JIS B0601: 2013 of 0.1 to 3.0 μm. It is characterized by containing a surfactant.

In the above agricultural film, the surface of the A layer has an arithmetic mean roughness Ra of 0.1 to 3.0 μm measured in accordance with JIS B0601: 2013, so that the haze value is high and direct light rays reach in the summer. Since the permeation into the house etc. is suppressed, the leaf burning is suppressed. Further, the agricultural film shows the arithmetic mean roughness Ra on the surface of the layer A due to the fact that the arithmetic average roughness Ra is in the above range and the layer A contains a surfactant. By expanding the surface so that it is inside the house or the like, the unevenness of the surface of the agricultural film is filled with water and smoothed during dew condensation in winter, and the haze value is lowered. For this reason, the above-mentioned agricultural film has a large amount of light transmission during dew condensation in winter, and sufficiently transmits sunlight even in winter when sunlight is weak. From the above, the agricultural film of the present invention suppresses the amount of light transmission when it is dried in summer and increases the amount of light transmission when dew condensation occurs in winter, so that these characteristics can be compatible with each other.

Hereinafter, the agricultural film of the present invention will be described.

The layer structure of the agricultural film of the present invention is not particularly limited as long as it has at least layer A. When the agricultural film of the present invention is composed of the A layer single layer, at least one side may show the arithmetic mean roughness Ra, and both sides may show the arithmetic mean roughness Ra. Moreover, as a preferable layer structure, for example, a layer structure having at least A layer, B layer and C layer in this order can be mentioned. Hereinafter, each layer will be described by taking this suitable layer structure as an example. In the agricultural film of the present invention, it is sufficient that at least one side of the A layer shows the arithmetic mean roughness Ra, and the surface showing the arithmetic mean roughness Ra is the surface of the A layer, which can be applied to a house or the like. This is the inner surface of the house, etc. when it is expanded. Further, when the agricultural film of the present invention has at least A layer, B layer and C layer in this order, the surface of the A layer opposite to the surface on which the B layer is laminated is the A layer. It is a surface showing the arithmetic mean roughness Ra.

(Layer A)
The layer A is a layer having an arithmetic average roughness Ra of the surface measured in accordance with JIS B0601: 2013 of 0.1 to 3.0 μm and containing a surfactant. The layer A is a layer located inside the greenhouse when the agricultural film of the present invention is used, for example, in a greenhouse-cultivated greenhouse.

The surface of the layer A has an arithmetic mean roughness Ra of 0.1 to 3.0 μm measured in accordance with JIS B0601: 2013. If Ra is less than 0.1 μm, the direct light rays in summer cannot be reduced, and if it exceeds 3.0 μm, the haze value does not decrease sufficiently during dew condensation in winter and the amount of light transmission decreases, resulting in sunlight. In the weak winter, the sun's rays cannot be sufficiently transmitted. The Ra is preferably 0.3 to 2.0 μm, more preferably 0.5 to 1.0 μm.

Layer A contains a surfactant. The surfactant is not particularly limited, and for example, a nonionic surfactant, a cationic surface active agent, and an anionic surfactant can be used. Among these, nonionic surfactants are preferable in that condensed water can be dispersed on the surface of the A layer to further reduce the haze value.

Examples of the nonionic surfactant include glycerin fatty acid esters such as monoglyceride, acetylated monoglyceride, organic acid monoglyceride, and medium-chain fatty acid triglyceride; polyglycerin fatty acid esters such as diglycerin fatty acid ester; sorbitan fatty acid ester; and propylene glycol fatty acid ester. Can be mentioned. Among these, glycerin fatty acid ester, polyglycerin fatty acid ester, and sorbitan fatty acid ester can be preferably used.

As the nonionic surfactant, specifically, glycerin oleate, diglycerin oleate, diglycerin stearate, and 3 mol adduct of sorbitan palmitate ethylene oxide can be more preferably used.

The above-mentioned surfactant may be used alone or in combination of two or more.

The A layer may contain a polyolefin resin. The polyolefin-based resin is not particularly limited, and is a homopolymer of ethylene or α-olefin, a copolymer of ethylene and α-olefin, or a copolymer of a heterogeneous monomer containing ethylene or α-olefin as a main component. , Ethylene or α-olefin and polyunsaturated compounds such as conjugated diene or non-conjugated diene, copolymers with acrylic acid, methacrylic acid, vinyl acetate and the like can be used, for example, high density, low density or direct. Chain low density polyethylene, polypropylene, ethylene-propylene copolymer, ethylene-butene copolymer, ethylene-4-methyl-1-pentene copolymer, ethylene-vinyl acetate copolymer (EVA), ethylene-acrylic acid Examples thereof include copolymers. Of these, low-density polyethylene, linear low-density polyethylene, and ethylene-vinyl acetate copolymer are preferable, and linear low-density polyethylene and ethylene-vinyl acetate copolymer are more preferable. By using the above resin as the polyolefin-based resin, the agricultural film can exhibit even more excellent transparency and weather resistance, and the agricultural film can be made at a low price.

Further, in the present invention, an ethylene-α-olefin copolymer resin obtained by copolymerizing with a metallocene catalyst can be used as at least one component of the polyolefin resin. This is usually referred to as metallocene polyethylene, and is a copolymer of ethylene with α-olefins such as butene-1, hexene-1, 4-methylpentene-1, and octene.

When an ethylene-α-olefin copolymer is used as the polyolefin resin, the melt flow rate (MFR) measured by JIS-K7210 of the ethylene-α-olefin copolymer is 0.01 to 50 g / 10 minutes. Preferably, 0.1 to 40 g / 10 minutes is more preferable, 0.2 to 30 g / 10 minutes is further preferable, and 0.3 to 20 g / 10 minutes is particularly preferable. By setting the MFR in the above range, it becomes easy to adjust the arithmetic mean roughness Ra of the surface of the A layer, and the meandering of the film during molding (during film formation) and the load on the molding machine are reduced. Therefore, the moldability can be improved.

Density measured by JIS K7112 of the ethylene -α- olefin copolymer is preferably 0.880 to 0.930 g / cm ^3, more preferably 0.890~0.920g / cm ^3. By setting the density in a preferable range, it becomes easy to secure the transparency of the agricultural film, and it becomes easy to reduce the stickiness of the surface and suppress blocking.

The molecular weight distribution (weight average molecular weight / number average molecular weight) determined by gel permeation chromatography (GPC) of the ethylene-α-olefin copolymer is preferably 0.5 to 3.5, and 1.0 to 3. 0 is more preferable. By setting the molecular weight distribution in a preferable range, it is possible to reduce meandering of the film during molding (during film formation) and improve moldability, and it becomes easy to secure the mechanical strength of the agricultural film.

When linear low-density polyethylene is used as the polyolefin resin, the melt flow rate (MFR) measured by JIS-K7210 of the linear low-density polyethylene is preferably 0.01 to 50 g / 10 minutes, and 0. 1 to 40 g / 10 minutes is more preferable, 0.2 to 30 g / 10 minutes is further preferable, 0.3 to 20 g / 10 minutes is particularly preferable, and 1.0 to 2.5 g / 10 minutes is most preferable. By setting the MFR in the above range, it becomes easy to adjust the arithmetic mean roughness Ra of the surface of the A layer, and the meandering of the film during molding (during film formation) and the load on the molding machine are reduced. Therefore, the moldability can be improved.

Density measured by JIS K7112 of the linear low-density polyethylene is preferably from 0.880 to 0.930 g / cm ^3, more preferably 0.890~0.925g / cm ^3. By setting the density in a preferable range, it becomes easy to secure the transparency of the agricultural film, and it becomes easy to reduce the stickiness of the surface and suppress blocking.

When an ethylene-vinyl acetate copolymer is used as the polyolefin resin, the melt flow rate (MFR) measured by JIS-K7210 of the vinyl acetate copolymer is preferably 0.01 to 50 g / 10 minutes, and 0. 1 to 40 g / 10 minutes is more preferable, 0.2 to 30 g / 10 minutes is further preferable, 0.3 to 20 g / 10 minutes is particularly preferable, and 0.5 to 15 g / 10 minutes is most preferable. By setting the MFR in the above range, it becomes easy to adjust the arithmetic mean roughness Ra of the surface of the A layer, and the meandering of the film during molding (during film formation) and the load on the molding machine are reduced. Therefore, the moldability can be improved.

The ethylene - density measured by JIS K7112 vinyl acetate copolymer is preferably 0.910~0.940g / cm ^3, more preferably 0.920~0.935g / cm ^3. By setting the density in a preferable range, it becomes easy to secure the transparency of the agricultural film, and it becomes easy to reduce the stickiness of the surface and suppress blocking.

The ethylene-vinyl acetate copolymer preferably has a vinyl acetate content in the range of 1 to 50% by mass, more preferably 1 to 30% by mass, further preferably 2 to 20% by mass, and 3 to 15%. The mass% range is particularly preferred. By setting the vinyl acetate content in a preferable range, the hardness of the agricultural film can be optimized, so that the occurrence of wrinkles and slack can be effectively suppressed when the film is spread on the house. Further, since the slack of the agricultural film can be suppressed even at a high temperature in summer, it becomes easy to suppress the fluttering due to the slack and the tearing due to rubbing against the house structure.

The above-mentioned polyolefin resin may be used alone or in combination of two or more.

The layer A preferably contains two or more types of polyolefin resins having different melt flow rates as measured by JIS-K7210. With this configuration, it becomes easy to adjust the arithmetic mean roughness Ra on the surface of the A layer.

When the A layer contains two or more kinds of polyolefin resins having different melt flow rates measured by JIS-K7210, the polyolefin resins are ethylene-vinyl acetate copolymer, low density polyethylene and linear low. It is preferably at least one selected from the group consisting of density polyethylene, and more preferably at least one selected from the ethylene-vinyl acetate copolymer and linear low density polyethylene. With this configuration, it becomes easier to adjust the arithmetic mean roughness Ra on the surface of the A layer.

When the polyolefin-based resin is a linear low-density polyethylene, the linear low-density polyethylene is a linear low-density polyethylene having a melt flow rate of 1.7 g / 10 minutes or more as measured by JIS-K7210. It is preferable to include i) and linear low-density polyethylene (ii) having a melt flow rate of less than 1.7 g / 10 minutes. With this configuration, it becomes easier to adjust the arithmetic mean roughness Ra on the surface of the A layer.

The upper limit of the melt flow rate of the linear low-density polyethylene (i) is not particularly limited, and is preferably 50 g / 10 minutes, more preferably 40 g / 10 minutes, further preferably 30 g / 10 minutes, and 20 g / 10 minutes. Especially preferable. The lower limit of the melt flow rate of the linear low-density polyethylene (ii) is not particularly limited, and is preferably 0.01 g / 10 minutes, more preferably 0.5 g / 10 minutes, and 1.0 g / 10 minutes. More preferred.

When the polyolefin resin is an ethylene-vinyl acetate copolymer, the ethylene-vinyl acetate copolymer has a melt flow rate of 5.0 g / 10 minutes or more as measured by JIS-K7210. It is preferable to contain the polymer (i) and the ethylene-vinyl acetate copolymer (ii) having a melt flow rate of less than 5.0 g / 10 minutes. With this configuration, it becomes easier to adjust the arithmetic mean roughness Ra on the surface of the A layer.

The upper limit of the melt flow rate of the ethylene-vinyl acetate copolymer (i) is not particularly limited, and is preferably 50 g / 10 minutes, more preferably 40 g / 10 minutes, further preferably 30 g / 10 minutes, and 20 g / 10 minutes. Is particularly preferable. The lower limit of the melt flow rate of the ethylene-vinyl acetate copolymer (ii) is not particularly limited, and is preferably 0.01 g / 10 minutes, more preferably 0.5 g / 10 minutes, and 1.0 g / 10 minutes. Is more preferable.

The content of the polyolefin resin in the layer A is preferably 90 to 100% by mass, more preferably 95 to 99% by mass. By setting the content of the polyolefin resin in the layer A within the above range, the amount of light transmitted through the agricultural film of the present invention during dew condensation in winter is further increased, and even in winter when sunlight is weak, sunlight rays are transmitted. Is even more transparent.

The A layer may contain an ultraviolet absorber. The ultraviolet absorber is not particularly limited, and conventionally known ones can be used, and examples thereof include triazine-based ultraviolet absorbers, benzotriazole-based ultraviolet absorbers, and benzophenol-based ultraviolet absorbers.

The above-mentioned ultraviolet absorber may be used alone or in combination of two or more.

The content of the ultraviolet absorber is preferably 1 to 10 parts by mass, more preferably 0.1 to 1 part by mass with respect to 100 parts by mass of the polyolefin resin contained in the A layer. By setting the content in a preferable range, the agricultural film can further exert the ultraviolet ray suppressing effect and the bleed-out of the ultraviolet absorber can be suppressed.

The layer A may contain a hindered amine-based photostabilizer in which an organic group or an organic functional group is bonded to the nitrogen atom of the piperidine ring directly or via an oxygen atom (the hindered amine-based light stabilizer is the layer A). Not only that, it can be included in at least one layer of A layer, B layer and C layer, and it is particularly preferable to include it in all layers of A layer, B layer and C layer). The organic group means a functional group having little reactivity by itself, for example, a methyl group, and the organic functional group means a functional group having reactivity by itself.

Examples of such a hindered amine-based light stabilizer include a so-called NR-type hindered amine-based light stabilizer and a NOR-type hindered amine-based light stabilizer. The NR-type hindered amine-based light stabilizer refers to a hindered amine-based light stabilizer in which a carbon atom is directly bonded to the nitrogen atom of the piperidine ring, and the NOR-type hindered amine-based light stabilizer is a hindered amine-based light stabilizer. A light stabilizer in which a carbon atom is bonded to a nitrogen atom of the piperidine ring via an oxygen atom.

The NR-type hindered amine-based light stabilizer is not particularly limited, and conventionally known ones can be used. For example, an NR type hindered amine having one or more piperidine ring structures represented by the following formula (1) in the molecule can be mentioned.

Here, in the formula (1), R ₁ is an organic group in which a carbon atom is directly bonded to a piperidine ring nitrogen atom, or an organic functional group.

Examples of the organic group or the organic functional group in which the carbon atom is directly bonded to the piperidine ring nitrogen atom include, for example, a piperidine ring nitrogen atom having a carbon atom directly bonded to the piperidine ring nitrogen atom and having 1 or more carbon atoms and at least 1 or more carbon atoms. A functional group or compound containing a methyl group or a methylene group of the above can be mentioned. Examples of the compound having 1 or more carbon atoms and containing at least 1 or more methyl group or methylene group include alkyl groups, and also includes oligomers and polymers.

Specific examples of the NR-type hindered amine-based light stabilizer include those represented by the following formulas (2) to (10).

Here, in the formula (10), n is a natural number indicating the degree of polymerization (the number of repeating units).

As the NR-type hindered amine-based light stabilizer, it is preferable to use one represented by the above formula (10).

Examples of commercially available products of the NR type hindered amine-based light stabilizer represented by the above formula (10) include the trade name "TINUVIN 622" manufactured by BASF.

The molecular weight of the NR-type hindered amine-based light stabilizer is preferably 1000 or more, more preferably 2000 or more. By setting the molecular weight in a preferable range, it becomes easy to suppress the bleed-out of the NR-type hindered amine-based light stabilizer. The upper limit of the molecular weight is not particularly limited, but is about 5000.

The NOR-type hindered amine-based light stabilizer is not particularly limited, and conventionally known ones can be used. For example, NOR-type hindered amine having one or more piperidine ring structures represented by the following formula (11) in the molecule can be mentioned.

Here, in the formula (11), R ₂ is an organic group or an organic functional group.

The organic group or the organic functional group represents, for example, a functional group or compound having 1 or more carbon atoms and containing at least 1 or more methyl group or methylene group. Compounds having one or more carbon atoms and containing at least one methyl group or methylene group also include oligomers and polymers. Specifically, as R ₂ , for example, an alkyl group such as a propyl group can be mentioned.

Specific examples of the NOR-type hindered amine-based light stabilizer include those represented by the following formula (12).

Examples of commercially available products of the NOR type hindered amine-based light stabilizer represented by the above formula (12) include the trade name "TINUVIN 123" manufactured by BASF. Examples of other commercially available NOR-type hindered amine-based light stabilizers include BASF's product name "TINUVIN NOR 371", ADEKA Corporation's product name "LA-81", and Clariant Japan's product name "Hostavin". "NOW" can be mentioned.

The molecular weight of the NOR-type hindered amine-based light stabilizer is preferably 1000 or more, and more preferably 2000 or more. By setting the molecular weight in a preferable range, it becomes easy to suppress the bleed-out of the NOR-type hindered amine-based light stabilizer. The upper limit of the molecular weight is not particularly limited, but is about 5000.

The layer A may further contain a hindered amine light stabilizer (so-called NH-type hindered amine light stabilizer) in which a hydrogen atom is directly bonded to the nitrogen atom of the piperidine ring (the hindered amine light stabilizer is A). It can be included not only in the layer but also in at least one layer of A layer, B layer and C layer, and is particularly preferable to be included in all layers of A layer, B layer and C layer). By containing the hindered amine-based light stabilizer, the agricultural film of the present invention has more excellent weather resistance.

The NH-type hindered amine-based light stabilizer is not particularly limited, and conventionally known ones can be used. For example, NH-type hindered amine having one or more piperidine ring structures represented by the following formula (13) in the molecule can be mentioned.

Specific examples of the NH-type hindered amine-based light stabilizer include those represented by the following formulas (14) to (17).

In formula (14), R ₃ is a tert-octyl group, and n is a natural number indicating the degree of polymerization.

As the NH-type hindered amine-based light stabilizer, it is preferable to use one represented by the above formula (14).

Examples of commercially available products of the NH-type hindered amine-based light stabilizer represented by the above formula (14) include the trade name "CHIMASSORB 944" manufactured by BASF.

The molecular weight of the NH-type hindered amine-based light stabilizer is preferably 1000 or more, more preferably 2000 or more. By setting the molecular weight in a preferable range, it becomes easy to suppress the bleed-out of the NH-type hindered amine-based light stabilizer. The upper limit of the molecular weight is not particularly limited, but is about 5000.

The hindered amine-based light stabilizer preferably contains an NR-type hindered amine-based light stabilizer and an NH-type hindered amine-based light stabilizer. By using such a hindered amine-based light stabilizer, the agricultural film of the present invention is excellent in the initial ultraviolet deterioration suppressing effect and the long-term sustainability of the ultraviolet deterioration suppressing effect. Examples of the hindered amine light stabilizer (NR-NH mixed hindered amine light stabilizer) containing the NR type hindered amine light stabilizer and the NH type hindered amine light stabilizer include BASF's product name "TINUVIN 622" and BASF. Examples thereof include BASF's product name "TINUVIN 783", which is a mixture with the company's product name "CHIMASSORB 944".

When the A layer contains the hindered amine light stabilizer, the content is preferably 0.1 to 3 parts by mass, and 0.2 to 2 parts by mass with respect to 100 parts by mass of the polyolefin resin contained in the A layer. More preferably, 0.3 to 1 part by mass is further preferable. By setting the content in a preferable range, the agricultural film can exhibit even better weather resistance.

The layer A contains other additives such as antioxidants, heat stabilizers, lubricants, antistatic agents, colorants, antiblocking agents, and antifog agents as long as the effects of the present invention are not impaired. You may.

The layer A may contain inorganic particles such as an inorganic heat insulating agent, but preferably does not contain inorganic particles. Since the layer A does not contain inorganic particles, the amount of light transmitted during dew condensation in the agricultural film of the present invention in winter is further increased, and the sunlight is further transmitted even in winter when sunlight is weak.

(B layer)
The agricultural film of the present invention may have a B layer on a surface opposite to the surface of the A layer. The B layer is composed of a single layer or a plurality of layers containing a polyolefin resin, and it is preferable that at least one layer contains an inorganic heat insulating agent.

The polyolefin-based resin contained in the B layer is not particularly limited, and the same polyolefin-based resin that can be used in the A layer can be used. The polyolefin-based resin contained in the B layer is preferably an ethylene-vinyl acetate copolymer in that the agricultural film becomes more flexible and the stretching work becomes easier.

The B layer is composed of a single layer or a plurality of layers containing the polyolefin resin. The number of layers of the B layer is not particularly limited, but is preferably 1 to 3 layers, and more preferably 1 layer.

At least one layer constituting the B layer of the agricultural film of the present invention may contain an inorganic heat insulating agent.

The inorganic heat insulating agent is not particularly limited, but for example, talc, hydrotalcites, magnesium-aluminum-based composite hydroxide, lithium-aluminum-based composite hydroxide, and other composite hydroxides (alkali metal, alkaline earth metal). , Transition metal, Group 2B element, Hydroxide having at least two or more elements selected from Group 4B elements such as silicon) and the like. These may be used alone or in combination of two or more. Above all, it is preferable to use magnesium-aluminum-based composite hydroxide. By containing the above-mentioned inorganic heat-retaining agent, the heat-retaining property of the obtained agricultural film can be improved, and the extrusion fluctuation during film molding can be improved. Here, the extrusion fluctuation means that, for example, when a film in which an antifogging agent (for example, higher fatty acid esters) is kneaded is extruded into a film, a large amount of a low melting point antifogging agent is kneaded in the extruder. A phenomenon in which the resin composition slips and becomes difficult to extrude.

The content of the inorganic heat insulating agent in the B layer is preferably 1 to 20 parts by mass, and more preferably 5 to 15 parts by mass with respect to 100 parts by mass of the polyolefin resin contained in the B layer. By setting the content in a preferable range, it is easy to impart good heat retention to the agricultural film, and it is easy to sufficiently obtain the effect of improving extrusion fluctuation during film formation by extrusion molding.

The B layer may contain a hindered amine-based light stabilizer in which an organic group or an organic functional group is bonded to the nitrogen atom of the piperidine ring directly or via an oxygen atom. By containing the hindered amine-based light stabilizer, the agricultural film of the present invention is further excellent in weather resistance.

The hindered amine-based photostabilizer in which an organic group or an organic functional group is bonded to the nitrogen atom of the piperidine ring contained in the B layer directly or via an oxygen atom is not particularly limited, and is the same as that which can be used in the A layer. Can be used.

The B layer may further contain a hindered amine-based light stabilizer in which a hydrogen atom is directly bonded to a nitrogen atom of the piperidine ring. By containing the hindered amine-based light stabilizer, the agricultural film of the present invention is further excellent in weather resistance.

The hindered amine-based light stabilizer in which a hydrogen atom is directly bonded to the nitrogen atom of the piperidine ring contained in the B layer is not particularly limited, and the same one that can be used in the A layer can be used.

When the B layer is composed of a plurality of layers, the hindered amine-based photostabilizer in which a hydrogen atom is bonded to the nitrogen atom of the piperidine ring has an organic group or an organic functional group directly or via an oxygen atom on the nitrogen atom of the piperidine ring. It may be contained in the same layer as the bound hindered amine-based light stabilizer, or may be contained in a different layer. A hydrogen atom is added to the nitrogen atom of the piperidin ring because it is possible to suppress the bleed-out of the hindered amine light stabilizer caused by the extrusion effect caused by the high concentration of the hindered amine light stabilizer in the same layer. The bound hindered amine light stabilizer is preferably contained in a layer different from that of the hindered amine light stabilizer in which an organic group or an organic functional group is bonded to the nitrogen atom of the piperidine ring directly or via an oxygen atom.

As described above, the layer B is a hindered amine-based light stabilizer in which an organic group or an organic functional group is bonded to the nitrogen atom of the piperidine ring directly or via an oxygen atom as long as the effect of the present invention is not impaired. Alternatively, it may contain a hindered amine-based photostabilizer in which a hydrogen atom is directly bonded to a nitrogen atom of the piperidine ring. The types and contents thereof are basically the same as those described in the A layer. The content of the hindered amine light stabilizer contained in the B layer means a mass part with respect to 100 parts by mass of the polyolefin resin contained in the B layer (entire B layer) even when the B layer is composed of a plurality of layers. To do.

The B layer is added with other additives such as antioxidants, heat stabilizers, lubricants, antistatic agents, colorants, anti-blocking agents, anti-fog agents, and anti-fog agents as long as the effects of the present invention are not impaired. It may contain an agent.

(C layer)
The agricultural film of the present invention may have a C layer on the surface of the B layer opposite to the surface on which the A layer is laminated. The C layer preferably contains a polyolefin-based resin.

The polyolefin-based resin contained in the C layer is not particularly limited, and the same polyolefin-based resin that can be used in the A layer can be used.

The C layer may contain a hindered amine-based light stabilizer in which an organic group or an organic functional group is bonded to the nitrogen atom of the piperidine ring directly or via an oxygen atom. By containing the hindered amine-based light stabilizer, the agricultural film of the present invention has more excellent weather resistance.

The hindered amine-based photostabilizer in which an organic group or an organic functional group is bonded to the nitrogen atom of the piperidine ring contained in the C layer directly or via an oxygen atom is not particularly limited, and is the same as that which can be used for the A layer. Can be used.

The C layer may further contain a hindered amine-based light stabilizer in which a hydrogen atom is directly bonded to a nitrogen atom of the piperidine ring. By containing the hindered amine-based light stabilizer, the agricultural film of the present invention has more excellent weather resistance. The hindered amine-based light stabilizer in which a hydrogen atom is directly bonded to the nitrogen atom of the piperidine ring contained in the C layer is not particularly limited, and the same one that can be used for the A layer can be used.

As described above, the C layer is a hindered amine-based photostabilizer in which an organic group or an organic functional group is bonded to the nitrogen atom of the piperidine ring directly or via an oxygen atom as long as the effect of the present invention is not impaired. Alternatively, it may contain a hindered amine-based photostabilizer in which a hydrogen atom is directly bonded to a nitrogen atom of the piperidine ring. The types and contents thereof are the same as those described in Layer A.

The C layer is an inorganic heat insulating agent, an antioxidant, a heat stabilizer, a lubricant, an antistatic agent, a coloring agent, an anti-blocking agent, an anti-fog agent, an anti-fog agent, etc., as long as the effects of the present invention are not impaired. Other additives may be included.

The inorganic heat insulating agent is not particularly limited, but for example, talc, hydrotalcites, magnesium-aluminum-based composite hydroxide, lithium-aluminum-based composite hydroxide, and other composite hydroxides (alkali metal, alkaline earth metal). , Transition metal, Group 2B element, Hydroxide having at least two or more elements selected from Group 4B elements such as silicon) and the like. These may be used alone or in combination of two or more. Above all, it is preferable to use magnesium-aluminum-based composite hydroxide. By containing the inorganic heat insulating agent, the heat retaining property of the obtained agricultural film can be improved, and the extrusion fluctuation during film molding can be improved. When the resin composition contains an inorganic heat insulating agent, the effect of suppressing extrusion fluctuation can be obtained.

When the agricultural film of the present invention contains an inorganic heat insulating agent, the content of the inorganic heat insulating agent is preferably 1 to 10 parts by mass with respect to 100 parts by mass of the polyolefin resin, and is preferably 3 to 8 parts by mass. More preferably. By setting the content in a preferable range, it is easy to impart good heat retention to the agricultural film, and it is easy to sufficiently obtain the effect of improving extrusion fluctuation during film formation by extrusion molding.

When the agricultural film of the present invention contains the hindered amine light stabilizer, the content of the hindered amine light stabilizer is preferably 0.1 to 10 parts by mass with respect to 100 parts by mass of the polyolefin resin. , 0.2 to 5 parts by mass is more preferable, and 0.3 to 3 parts by mass is further preferable. By setting the content in a preferable range, good weather resistance of the agricultural film can be ensured, and in addition, when the content of the light stabilizer is in an appropriate range, the ultraviolet absorber contained in the agricultural film Bleedout can be suppressed.

The agricultural film of the present invention preferably has a haze value (Hzd) at the time of drying of 20 to 50%, more preferably 25 to 45%. When the haze value at the time of drying is in the above range, the amount of light transmission can be further suppressed at the time of drying in the summer, and the leaf burning of the cultivated product can be further suppressed.

In addition, in this specification, the haze value at the time of drying is based on JIS K7136 from the aspect which shows the arithmetic mean roughness Ra of the A layer of the agricultural film of this invention [a haze of a plastic-transparent material. It is a value measured using a haze meter according to [How to obtain].

The agricultural film of the present invention preferably has a haze value (Hzd) at the time of dew condensation of less than 20%, more preferably 15% or less. When the haze value at the time of drying is within the above range, the amount of light transmitted during dew condensation in winter becomes larger, and the sun's rays are further transmitted even in winter when sunlight is weak. Further, the lower limit of the haze value at the time of dew condensation is not particularly limited, and 1% is preferable, 5% is more preferable, and 10% is further preferable.

In this specification, the method for measuring the haze value at the time of dew condensation is as follows. That is, assuming the time of dew condensation, liquid paraffin is dropped from the surface of the A layer of the agricultural film of the present invention showing the arithmetic mean roughness Ra, and a glass plate is covered with a sample for measuring the haze value at the time of dew condensation. Prepare. From the direction of the glass plate of the measurement sample, the haze value of the measurement sample is measured using a haze meter according to [How to determine the haze of plastic-transparent material] in accordance with JIS K7136.

In the agricultural film of the present invention, the difference (Hzd-Hzw) between the haze value (Hzd) at the time of drying and the haze value (Hzw) at the time of dew condensation is preferably 10% or more, and preferably 15% or more. More preferably, it is more preferably 20% or more. Since the difference between the haze value during drying and the haze value during dew condensation is within the above range, the amount of light transmission is suppressed during drying in summer, the leaf burning of cultivated plants can be suppressed, and in winter. Since the amount of light transmitted during dew condensation is large and the sunlight is sufficiently transmitted even in winter when the sunlight is weak, the effect of the present invention that it can be suitably used for cultivation of agricultural crops is exhibited even more efficiently. can do. The upper limit of the difference between the haze value at the time of drying and the haze value at the time of dew condensation is not particularly limited, and is preferably 50%, more preferably 45%, further preferably 40%, and particularly preferably 30%.

FIG. 1 shows a cross-sectional view showing an example of a layer structure when the agricultural film of the present invention has an A layer, a B layer, and a C layer in this order. When the agricultural film of the present invention is used for greenhouse cultivation or tunnel cultivation, the amount of light transmission is suppressed during drying in summer by using the layer A so as to be inside the greenhouse or the like, and the leaves of the cultivated product. It can suppress burning, has a large amount of light transmission during dew condensation in winter, and sufficiently transmits sunlight even in winter when sunlight is weak, so it can be suitably used for cultivation of agricultural crops. The effect of the present invention can be exhibited even more efficiently.

The thickness of the agricultural film of the present invention is not particularly limited, but is preferably 30 to 300 μm, more preferably 40 to 200 μm, and even more preferably 50 to 150 μm. By setting the thickness in a preferable range, the agricultural film has an appropriate elasticity, and good handleability and workability can be easily obtained.

The thickness ratio of each layer constituting the agricultural film of the present invention is preferably A layer: B layer: C layer = 1: 1: 1 to 1: 6: 1, preferably 1: 2: 1 to 1: 4. 1 is more preferable.

The present invention is also an agricultural house, an agricultural curtain or an agricultural tunnel having the above agricultural film. By spreading the agricultural film on an agricultural house, an agricultural curtain or an agricultural tunnel with the surface showing the arithmetic average roughness Ra of the layer A inside, the amount of light transmission is suppressed during drying in the summer. The agricultural house of the present invention can suppress the burning of leaves of cultivated plants, and has a large amount of light transmission during dew condensation in winter, and sufficiently transmits sunlight even in winter when sunlight is weak. , Agricultural curtains or agricultural tunnels are suitable for growing agricultural crops.

Hereinafter, examples of the present invention will be described. The present invention is not limited to the following examples.

Examples 1 to 7, Comparative Examples 1 to 4
A light stabilizer and an antifogging agent with respect to 100 parts by mass of the polyolefin resin so that each layer of the A layer, the B layer, and the C layer has the composition shown in Table 1 in each extruder of the three-layer extruder. And magnesium-aluminum-based composite hydroxide were added and melt-kneaded.

As each raw material used in Table 1, those shown in Table 2 were used.

The three layers are co-extruded by the inflation method so that the thickness of each layer of the A layer, the B layer, and the C layer is A layer: B layer: C layer = 1: 3: 1 (thickness ratio 20:60:20). , An agricultural film having a thickness of 150 μm was obtained.

The agricultural films of the obtained Examples and Comparative Examples were evaluated as follows.

<Arithmetic Mean Roughness Ra on the surface of layer A>
The arithmetic mean roughness Ra of the surface of the A layer (the surface opposite to the surface on which the B layer is laminated) was measured by a measuring method based on JIS B0601: 2013.

<Haze value during drying (Hzd)>
From the surface of the A layer, the haze value of the agricultural film at the time of drying was measured using a haze meter according to [How to determine the haze of the plastic-transparent material] according to JIS K7136.

<Haze value at the time of dew condensation (Hzw)>
Assuming the time of dew condensation, liquid paraffin was dropped from the surface of the A layer of the agricultural film showing the arithmetic mean roughness Ra, and a glass plate was covered to prepare a sample for measuring the haze value at the time of dew condensation. From the direction of the glass plate of the measurement sample, the haze value of the measurement sample was measured using a haze meter according to [How to determine the haze of plastic-transparent material] in accordance with JIS K7136.

<Difference between haze value during drying and haze value during condensation (Hzd-Hzw)>
The difference between the haze value at the time of drying and the haze value at the time of dew condensation measured by the above method was calculated based on the following formula.
(Hsd-Hzw) (%) = [Haze value during drying (Hzd) -Haze value during dew condensation (Hzw)]

<Prevention of leaf burning>
The leaves of the rice were irradiated with an incandescent lamp at 120 W for 12 hours under the condition that the distance between the rice and the incandescent lamp was 50 cm. The condition of the leaves after irradiation with incandescent lamp was visually observed and evaluated according to the following evaluation criteria. If it is more than Δ evaluation, it is evaluated that there is no problem in actual use.
◯: No or almost no leaf burning is seen.
Δ: Leaf burns are slightly seen, but there is no problem.
X: Leaf burning is strongly occurring.

<Visibility inside the tunnel or inside the house>
The visibility was evaluated assuming the visibility inside the tunnel or the inside of the house at the time of dew condensation. Specifically, the visibility of the agricultural film at the time of dew condensation was visually observed and evaluated according to the following evaluation criteria. If it is more than Δ evaluation, it is evaluated that there is no problem in actual use.
◯: The cultivated crops inside can be clearly seen.
Δ: The outline of the cultivated crop inside is slightly blurred, but it is visible.
X: The cultivated crops inside are blurred and cannot be visually recognized.

<Heat retention inside tunnel or house>
A 120 W incandescent lamp was installed at a position 50 cm away from the spectroradiometer (manufactured by Hideko Seiki Co., Ltd .: model number MS-720). An agricultural film was placed between the spectroradiometer and the incandescent lamp at a position 20 cm from the spectroradiometer, and the amount (intensity) A1 of light emitted at a wavelength of 1050 nm was measured. In addition, the amount of light radiation (intensity) A0 at a wavelength of 1050 nm when no film was installed was measured. The radiation amount ratio was calculated according to the following formula and evaluated according to the following evaluation criteria.
(Radiation amount ratio) (%) = [A1 / A0] × 100
If it is more than Δ evaluation, it is evaluated that there is no problem in actual use.
◯: The radiation amount ratio is 95% or more.
Δ: The radiation amount ratio is 90% or more and less than 95%.
X: The radiation amount ratio is less than 90%.

The results are shown in Table 1.

In Table 2, MFR is a value measured under the conditions of a temperature of 190 ° C. and a load of 21.18 N in accordance with JIS K-7210.

1 ... Agricultural film 2 ... A layer 3 ... B layer 4 ... C layer

Claims (9)

Agricultural film with at least layer A
The surface A layer has an arithmetic mean roughness Ra of 0.1 to 3.0 μm as measured in accordance with JIS B0601: 2013, and contains a surfactant .
The layer A does not contain inorganic particles .
Agricultural film characterized by that. The agricultural film according to claim 1, wherein the layer A contains two or more types of polyolefin resins having different melt flow rates. The agricultural film according to claim 2, wherein the polyolefin-based resin is at least one selected from the group consisting of an ethylene-vinyl acetate copolymer, low-density polyethylene, and linear low-density polyethylene. The agricultural film according to any one of claims 1 to 3, wherein the surfactant is at least one selected from the group consisting of glycerin fatty acid ester, polyglycerin fatty acid ester and sorbitan fatty acid ester. The agricultural film according to any one of claims 1 to 4, wherein the difference (Hzd-Hzw) between the haze value (Hzd) at the time of drying and the haze value (Hzw) at the time of dew condensation is 10% or more. The agricultural film according to claim 5, wherein the haze value (Hzd) at the time of drying is 20 to 50%. The agricultural film according to claim 5 or 6, wherein the haze value (Hzw) at the time of dew condensation is less than 20%. It has at least the A layer, the B layer and the C layer in this order.
The B layer is composed of a single layer or a plurality of layers containing a polyolefin resin, and at least one layer contains an inorganic heat insulating agent.
The C layer contains a polyolefin resin.
The agricultural film according to any one of claims 1 to 7 . An agricultural house, an agricultural curtain or an agricultural tunnel having the agricultural film according to any one of claims 1 to 8 .