KR102140923B1 - Agricultural film and agricultural and horticultural facility - Google Patents

Abstract

Provided is an agricultural film having high light scattering property in summer with strong solar radiation, more fragile, and easier handling. The agricultural film has at least one layer composed of a continuous phase and a dispersed phase, and satisfies the following (A) and (B); (A) The ratio of the area of the cross section of the dispersed phase having a circular equivalent diameter of 1 μm or more and 10 μm or less among the dispersed phases is 1% or more and 30% or less with respect to the area of the cross section of the layer, and (B) birefringence (Δn) is 1.15 × 10 ^-3 or less.

Description

AGRICULTURAL FILM AND AGRICULTURAL AND HORTICULTURAL FACILITY

The present invention relates to agricultural films and agricultural horticultural facilities.

In Patent Document 1, a film formed of a resin composition containing a filler in a base resin having a birefringence (Δn) of Δn <0.9 × 10 ^-3 measured in accordance with JIS K 7142, and molded from the resin composition A stretched porous film is described.

In Patent Document 2, in order to increase light scattering property in summer with strong solar radiation, the content of the monomer unit based on vinyl acetate is 15 to 30% by weight of an ethylene-vinyl acetate copolymer, and the average particle size is 3 to 15 µm. An agricultural film having a layer containing a methyl methacrylate-styrene copolymer particle as an intermediate layer is described.

Japanese Patent Application Publication "Japanese Patent Application Publication No. 2007-238822" Japanese Patent Application Publication "Japanese Patent Application Publication No. 2014-209903"

In the case of agricultural film, when using the film for electric field farming, the stress concentrates on the part in contact with the frame, and may be cleaved or broken. Since the porous film described in Patent Literature 1 is porous, it is easy to be cleaved or broken, and handling is not easy when used as a film for electrical equipment in agricultural and horticultural facilities. Moreover, also for the agricultural film described in patent document 2, the agricultural film which is hard to break|rupture and is easy to handle is calculated|required.

One aspect of the present invention aims to provide a new agricultural film having high light scattering property in summer when sunlight is strong, which is more fragile and easy to handle.

In order to solve the said subject, the agricultural film concerning one aspect of this invention has at least 1 layer which consists of a continuous phase and a disperse phase, and satisfies following (A) and (B); (A) In the cross section cut in the direction perpendicular to the film surface and in a direction parallel to the slow axis in the film surface, the area of the cross section of the dispersed phase having a circular equivalent diameter of 1 µm or more and 10 µm or less in the dispersed phase The ratio is 1% or more and 30% or less, and (B) the birefringence (Δn) is 1.15 × 10 ^-3 or less with respect to the area of the cross-section of the layer.

In addition, another preferred embodiment of the present invention is an agricultural horticultural facility in which the agricultural film is extended to an agricultural horticultural facility frame.

ADVANTAGE OF THE INVENTION According to one aspect of this invention, the light scattering property in summer with strong solar radiation is high, it is hard to break|rupture easily, and the agricultural film for easy handling and its manufacturing method can be provided.

Hereinafter, one embodiment of the present invention will be described in detail.

<Agricultural film>

The agricultural film according to one embodiment of the present invention has a birefringence (Δn) of 1.15 × 10 ^-3 or less, and has at least one layer composed of a continuous phase and a dispersed phase. The agricultural film according to one embodiment of the present invention can be preferably used as an exterior or interior film of a greenhouse for plant cultivation, and a covering material of a tunnel.

(Birefringence)

In the present specification, the birefringence (Δn) is an in-plane retardation (in-plane) measured at a measurement wavelength of 586 nm using a phase difference measuring device (such as KOBRA series manufactured by Oji Measurement Instruments Co., Ltd.) using the parallel Nicole rotation method as a measurement principle. The phase difference) (Re) and the total thickness (D) of the film are used to refer to the value calculated by the following formula (1).

Δn (birefringence) = Re/D (total thickness) (1)

The birefringence (Δn) is 1.15 × 10 ^-3 or less, more preferably 1.0 × 10 ^-3 or less, and most preferably 0.8 × 10 ^-3 or less. When the birefringence (Δn) is 1.15 × 10 ^-3 or less, in general, when extending to an agricultural or horticultural facility, the goodness of elongation in the MD (Machine Direction) direction in an agricultural film can be improved. For this reason, even in a case where the film is strongly pulled horizontally to fix the looseness of the film at the time of battlefield for the agricultural and horticultural facility, it is preferable to prevent the agricultural film from being ruptured or opened at the contact portion with the agricultural horticultural facility frame. It is possible to obtain an agricultural film with improved handling properties. The lower limit of the birefringence (Δn) is not particularly limited, but is preferably 0.05×10 ⁻³ or more.

In addition, the birefringence of the agricultural film according to an aspect may be obtained as the birefringence (Δn) of only the layer when the agricultural film is composed of only a layer composed of a continuous phase and a dispersed phase, and a layer other than a layer composed of a continuous phase and a dispersed phase. (In other words, when it is provided with other layers mentioned later), it is good to obtain|require it as the birefringence of the agricultural film which consists of all of these layers.

The agricultural film having the birefringence (Δn) described above can be produced by appropriately adjusting the conditions of the raw material and the manufacturing method. As the layer composed of the continuous phase and the dispersed phase (and the layers other than the layer composed of the continuous phase and the dispersed phase) included in the agricultural film, a resin composition serving as a general raw material for the agricultural film can be used. As a raw material for the layer composed of the continuous phase and the dispersed phase, a thermoplastic resin serving as the continuous phase and at least one selected from organic particles, inorganic particles, and thermoplastic resin serving as the dispersed phase may be suitably used in combination. The more preferable raw material of the layer composed of the continuous phase and the dispersed phase will be described later in the [layer consisting of the continuous phase and the dispersed phase]. As a raw material for the layers other than the layer composed of the continuous phase and the dispersed phase, a general thermoplastic resin may be used, and it is preferable to use a polyolefin-based resin (hereinafter, a layer other than the layer composed of the continuous phase and the dispersed phase is a polyolefin-based resin layer) Also called). The conditions of a more preferable production method will be described later in <Method for Producing Agricultural Film>.

(Haze value)

In addition, in this specification, the haze value is a value measured using a temperature measurement haze meter (THM-150TL) manufactured by Murakami Color Technology Research Institute in accordance with JIS K 7136:2000 for measurement conditions other than temperature. In the present specification, the light scattering property of the film can be evaluated by the haze value.

In the agricultural film according to one embodiment of the present invention, the haze value at 40°C is preferably 15% or more, and more preferably 20% or more. When the haze value at 40°C is 15% or more, the light irradiated to the film can be preferably scattered in the summer with a large amount of solar radiation.

In the agricultural film according to one embodiment of the present invention, the thickness of the layer composed of the continuous phase and the dispersed phase is preferably 1 μm or more, and more preferably from the viewpoint of increasing light scattering properties in the summer reaching 40° C. Is 30 µm or more. From the viewpoint of improving the handleability by lightening the weight of the film, it is preferably 500 µm or less, and more preferably 300 µm or less.

[Layer consisting of continuous phase and dispersed phase]

The layer consisting of the continuous phase and the dispersed phase is the main layer constituting the agricultural film according to one aspect, and is simply described as "layer" in this specification, and unless otherwise specified, the "layer" refers to the continuous phase and It shows the layer which consists of a dispersed phase.

The agricultural film according to one embodiment of the present invention has a circular equivalent diameter of 1 µm or more and 10 µm in the cross-section of the film cut in a direction perpendicular to the film surface and in a direction parallel to a slow axis in the film plane. The ratio of the area of the cross section of the dispersed phase below is preferably 1% or more and 30% or less, and more preferably 2% or more and 25% or less, based on the area of the cross section of the layer. In addition, the slow axis in the film plane is obtained together with the in-plane retardation (Re) used for the calculation of the birefringence (Δn). When the ratio of the area of the cross section of the dispersed phase having a circle equivalent diameter of 1 µm or more and 10 µm or less is within a range of 1% or more and 30% or less, satisfactory elongation and breaking strength in the MD direction can be secured. In short, it is possible to obtain an agricultural film having a high tensile elongation at break in the MD direction.

In the present specification, the dispersed phase means a phase composed of individual particles dispersed in a continuous phase, and the circular equivalent diameter of the dispersed phase means the circular equivalent diameter of the particle obtained for each observed particle. Here, "circular equivalent diameter" means the diameter of a circle having the same area as the cross-sectional area of particles to be photographed on the cross-section of the photographed layer, and can be obtained by an image analysis system from an image of a cross-section of an agricultural film.

In the resin composition constituting the layer composed of the continuous phase and the dispersed phase, the mixing ratio of the components constituting the continuous phase and the components constituting the dispersed phase is not particularly limited, but can be set as shown below.

When the total amount of the components constituting the continuous phase and the components constituting the dispersed phase is 100 parts by mass, the content of the components constituting the continuous phase is preferably 50 parts by mass or more, more preferably 60 parts by mass or more, It is more preferably 65 parts by mass or more, and particularly preferably 70 parts by mass or more. Moreover, content of the component which comprises a continuous phase is 98 mass parts or less preferably, More preferably, it is 95 mass parts or less, More preferably, it is 90 mass parts or less, Especially preferably, it is 85 mass parts or less. .

Moreover, when the total amount of the components constituting the continuous phase and the components constituting the dispersed phase is 100 parts by mass, the content of the components constituting the dispersed phase is preferably 2 parts by mass or more, more preferably 5 parts by mass or more , More preferably 10 parts by mass or more, and particularly preferably 15 parts by mass or more. Moreover, it is 50 mass parts or less preferably, More preferably, it is 40 mass parts or less, More preferably, it is 35 mass parts or less, Especially preferably, it is 30 mass parts or less.

[Continuous Award]

It is preferable that a continuous phase contains a thermoplastic resin. Examples of the thermoplastic resin include ethylene-based copolymers, polyolefin-based resins, and combinations thereof.

(Ethylene-based copolymer)

As the ethylene-based copolymer, for example, an ethylene-vinyl ester copolymer, a copolymer of ethylene and an unsaturated carboxylic acid and/or a derivative thereof (hereinafter also referred to as an ethylene-unsaturated carboxylic acid (derivative) copolymer), ethylene- and α-olefin copolymers. Ethylene-based copolymers may be used alone, or two or more types of ethylene-based copolymers may be used in combination.

The ethylene-vinyl ester copolymer refers to an ethylene-vinyl ester copolymer having a monomer unit derived from ethylene and a monomer unit derived from vinyl ester as main monomer units. The ethylene-vinyl ester copolymer may be a random copolymer of an ethylene monomer and a vinyl ester monomer, or a block copolymer.

Examples of the vinyl ester that is a constituent material of the ethylene-vinyl ester copolymer include vinyl esters of fatty acids, and those having 2 to 4 carbon atoms in the fatty acid, more specifically, vinyl acetate, vinyl propionate, and the like. Can be heard. In one aspect of the present invention, the ethylene-vinyl ester copolymer may contain monomer units derived from two or more types of vinyl esters. Especially, it is preferable that vinyl ester is vinyl acetate.

Specific examples of the ethylene-vinyl ester copolymer having a monomer unit derived from ethylene and a monomer unit derived from vinyl ester include ethylene-vinyl acetate copolymer, ethylene-vinyl propionate copolymer, and the like, in particular, ethylene -Vinyl acetate copolymer (EVA) is preferably used. Moreover, the ethylene-vinyl ester copolymer may be used alone, or two or more types of ethylene-vinyl ester copolymers may be used in combination.

Further, the ethylene-vinyl ester copolymer may contain monomer units derived from monomers other than ethylene and vinyl ester.

Commercially available products that can be used as the ethylene-vinyl ester copolymer include, for example, Evatate (registered trademark) (manufactured by Sumitomo Chemical Co., Ltd.), Summit (registered trademark) (manufactured by Sumitomo Chemical Corporation), and Novatech (registered trademark) EVA. (Manufactured by Nihon Polyethylene Co., Ltd.), Ultrasen (registered trademark) (manufactured by Tosoh Corporation), Santec (registered trademark) EVA (manufactured by Asahi Chemical Co., Ltd.), EVAFLEX (registered trademark) (Mitsui DuPont Polychemical Co., Ltd.), etc. Can.

In the ethylene-vinyl ester copolymer, the content of the monomer unit derived from the vinyl ester is preferably 7 mass% or more and 30 mass% or less, more preferably 10 mass% or more and 28 mass% or less, and more preferably Is 12 mass% or more and 25 mass% or less.

Moreover, in the ethylene-vinyl ester copolymer, the content of the monomer unit derived from ethylene is preferably 70 mass% or more and 93 mass% or less, more preferably 72 mass% or more and 90 mass% or less, and more preferably It is 75 mass% or more and 88 mass% or less.

When two or more types of ethylene-vinyl ester copolymers are used together as the ethylene-vinyl ester copolymer, the content (E) of the monomer units derived from ethylene in the copolymer is calculated by the following formula (2).

E (mass%) =

(E ₁ · W ₁ + E ₂ · W ₂ +… + E _m · W _m )/(W ₁ + W ₂ +… W _m ) (2)

(However, it is said that ethylene-vinyl ester copolymer 1, ethylene-vinyl ester copolymer 2, ... m-type ethylene-vinyl ester copolymer of ethylene-vinyl ester copolymer m are used together (m is an integer of 3 or more), and ethylene -The content (mass %) of monomer units derived from ethylene in the vinyl ester copolymer k is E _k , and the content of the ethylene-vinyl ester copolymer k in the resin composition is W _k (k is from 1 to m essence).)

In the same manner, when two or more types of ethylene-vinyl ester copolymers are used in combination as the ethylene-vinyl ester copolymer, the content (E') of the monomer unit derived from the vinyl ester in the copolymer is the following formula (3). Is calculated by

E'(mass %) =

_{(E '1 · W 1 +} E' 2 · W 2 + ... + E 'm · W m) / (W 1 + W 2 + ... W m) (3)

(However, it is said that copolymer m, copolymer 2, ... m copolymers of copolymer m are used together (m is an integer of 3 or more), and the content of monomer units derived from vinyl ester in copolymer k (mass to%) is the content of the copolymer of E k _'k, the resin composition to W _k (k is an integer from 1 to m).)

In addition, the content of the monomer unit derived from ethylene and the content of the monomer unit derived from the vinyl ester in the ethylene-vinyl ester copolymer can be quantified by a saponification method, and more specifically, the ethylene-based copolymer. When is an ethylene-vinyl acetate copolymer, it can be quantified according to JIS K 7192:1999.

The density of the ethylene-vinyl ester copolymer is 925 kg/m 3 or more, more preferably 930 kg/m 3 or more, more preferably 933 kg/m 3 or more, 955 kg/m 3 or less, and 952 kg/m 3 or less It is more preferable that it is 950 kg/m 3 or less, and more preferably. The density of the ethylene-vinyl ester copolymer is in the range of 925 kg/m 3 or more and 955 kg/m 3 or less, and in addition, the components described later in the disperse phase are included, so that in the summer when the temperature reaches around 40° C., the film The light transmittance of the film at 40°C can be kept constant while increasing the light scattering property. In addition, the density of the ethylene-vinyl ester copolymer is a value measured according to the method specified in Method A of JIS K 7112:1999, and is a density measured at 23°C.

When two or more types of ethylene-vinyl ester copolymers are used in combination as the ethylene-vinyl ester copolymer, the density (d) of the ethylene-vinyl ester copolymer may be estimated by the following formula (4).

d (㎏/㎥) =

(d ₁ ·W ₁ + d ₂ ·W ₂ +… + d _m ·W _m )/(W ₁ + W ₂ +… W _m ) (4)

(However, ethylene-vinyl ester copolymer 1, ethylene-vinyl ester copolymer 2, ... m-type ethylene-vinyl ester copolymer of ethylene-vinyl ester copolymer m is used together (m is an integer of 3 or more), and ethylene -The density (unit: kg/㎥) of the vinyl ester copolymer k is d _k , and the content (unit: kg) of the ethylene-vinyl ester copolymer k in the resin composition is W _k (k is an integer from 1 to m) ).)

That is, in one aspect, the density (d) of the ethylene-vinyl ester copolymer contained in the resin composition may be adjusted by using two or more types of ethylene-vinyl ester copolymers in combination.

The melt flow rate (MFR) of the ethylene-vinyl ester copolymer is preferably 0.05 g/10 minutes or more and 20 g/10 minutes or less, and more preferably 0.1 g/10 minutes or more and 15 g/10 minutes or less. . The MFR is measured according to JIS K 7210:1999 under the method A under conditions of a temperature of 190°C and a load of 21.18 N.

The ethylene-unsaturated carboxylic acid (derivative) copolymer is an ethylene-unsaturated carboxylic acid (derivative) copolymer having monomer units derived from ethylene and monomer units derived from unsaturated carboxylic acids and/or derivatives thereof as main monomer units. Says coalescence. The ethylene-unsaturated carboxylic acid (derivative) copolymer may be a random copolymer of an ethylene monomer and an unsaturated carboxylic acid monomer and/or a derivative monomer of an unsaturated carboxylic acid, or a block copolymer.

Examples of the unsaturated carboxylic acid used as a constituent material of the ethylene-unsaturated carboxylic acid (derivative) copolymer include unsaturated monocarboxylic acids such as (meth)acrylic acid, crotonic acid, isocrotonic acid, and 3-butene acid; And unsaturated dicarboxylic acids such as maleic acid and fumaric acid. Especially, unsaturated monocarboxylic acid is preferable, for example, (meth)acrylic acid is preferable. In addition, in this specification, acrylic acid and methacrylic acid are collectively described as (meth)acrylic acid.

Derivatives of unsaturated carboxylic acids that are constituent materials of ethylene-unsaturated carboxylic acid (derivative) copolymers include salts of the unsaturated carboxylic acids, unsaturated carboxylic acid esters, acid anhydrides, unsaturated carboxylic acid amides, and unsaturated carboxylic acids And carboxylic acid imides, and preferably salts of unsaturated carboxylic acids and unsaturated carboxylic acid esters. Examples of the salt of the unsaturated carboxylic acid include sodium salt, potassium salt, calcium salt, and zinc salt of the unsaturated carboxylic acid. Examples of the unsaturated carboxylic acid ester include unsaturated carboxylic acid alkyl esters such as unsaturated carboxylic acid methyl ester, unsaturated carboxylic acid ethyl ester, and unsaturated carboxylic acid butyl ester; Unsaturated carboxylic acid aryl esters such as unsaturated carboxylic acid phenyl esters; And unsaturated carboxylic acid glycidyl esters.

Specific examples of the ethylene-unsaturated carboxylic acid (derivative) copolymer having a monomer unit derived from ethylene and an unsaturated carboxylic acid and/or derivative thereof in the present invention are ethylene-(meth)acrylic acid Ethylene-unsaturated carboxylic acid copolymers such as copolymers; Ionomers in which part or all of the carboxyl groups of ethylene-unsaturated carboxylic acid copolymers such as ethylene-(meth)acrylic acid copolymers are neutralized with metal ions such as sodium, potassium, calcium and zinc; And ethylene-unsaturated carboxylic acid ester copolymers such as ethylene-(meth)acrylate copolymer, ethylene-(meth)acrylate copolymer, and ethylene-(meth)acrylate copolymer. Specifically, ethylene-( A meth)acrylic acid copolymer, an ethylene-(meth)acrylate methyl copolymer, an ethylene-(meth)acrylate copolymer, etc. are preferably used. Moreover, in one aspect of the present invention, the ethylene-unsaturated carboxylic acid (derivative) copolymer may contain monomer units derived from two or more kinds of unsaturated carboxylic acids and/or derivatives thereof.

As a specific example of an ethylene-unsaturated carboxylic acid (derivative) copolymer, the following are mentioned, for example.

(i) Ethylene-unsaturated carboxylic acid copolymer

New Krell (registered trademark) (ethylene-methacrylic acid copolymer, manufactured by Mitsui DuPont Polychemical Co., Ltd.)

(ii) an ionomer in which part or all of the carboxyl groups of the ethylene-unsaturated carboxylic acid copolymer are neutralized with metal ions.

Hymilan (Registered Trademark) (Ionomer, manufactured by Mitsui DuPont Polychemical Co., Ltd., in which a part of the carboxyl groups of the ethylene-methacrylic acid copolymer is neutralized with zinc ions or sodium ions)

(iii) Ethylene-unsaturated carboxylic acid ester copolymer

ARC LIFT (registered trademark) (ethylene-methyl methacrylate copolymer, manufactured by Sumitomo Chemical Co., Ltd.), Rex Pearl (registered trademark) EMA (ethylene-methyl acrylate copolymer, manufactured by Nihon Polyethylene Corporation), Rex Pearl (registered trademark) EEA (Ethylene-ethyl acrylate copolymer, manufactured by Nihon Polyethylene Co., Ltd.), Rothril (registered trademark) (Ethylene-methyl acrylate copolymer or ethylene-butyl acrylate copolymer, manufactured by Arkema), ElBary (registered trademark) AC (ethylene- Either methyl acrylate copolymer, ethylene-ethyl acrylate copolymer, ethylene-butyl acrylate copolymer, manufactured by DuPont)

Ethylene-unsaturated carboxylic acid (derivative) copolymers may be used alone, or two or more types of ethylene-unsaturated carboxylic acid (derivative) copolymers may be used in combination.

The content of the monomer unit derived from the unsaturated carboxylic acid and/or its derivative in the ethylene-unsaturated carboxylic acid (derivative) copolymer is from the balance of the film stiffness and the light scattering property (haze value) at 40°C. , Preferably 10 mass% or more and 40 mass% or less, more preferably 15 mass% or more and 35 mass% or less, still more preferably 20 mass% or more and 30 mass% or less (however, ethylene-unsaturated carboxylic acid (Derivative) The mass of the copolymer is 100 mass%).

The content of the monomer unit derived from the unsaturated carboxylic acid and/or its derivative in the ethylene-unsaturated carboxylic acid (derivative) copolymer can be measured by infrared absorption spectrum analysis.

The content of the monomer unit derived from ethylene in the ethylene-unsaturated carboxylic acid (derivative) copolymer is preferably 60% by mass or more from the balance of the film stiffness and the light scattering property (haze value) at 40°C. 90 mass% or less, more preferably 65 mass% or more and 85 mass% or less, still more preferably 70 mass% or more and 80 mass% or less (however, the mass of the ethylene-unsaturated carboxylic acid (derivative) copolymer) 100 mass%).

The content of the monomer unit derived from ethylene in the ethylene-unsaturated carboxylic acid (derivative) copolymer is 100 as the content of the monomer unit derived from the unsaturated carboxylic acid and/or its derivative measured by infrared absorption spectrum analysis. It can be calculated by subtracting from mass%.

When two or more types of ethylene-unsaturated carboxylic acid (derivative) copolymers are used together as an ethylene-unsaturated carboxylic acid (derivative) copolymer, the content of monomer units derived from ethylene (E'') in the copolymer is , It is calculated by the following formula (5).

E'' (mass%) =

_{(E '' 1 · W '} 1 + E''2 · W' 2 + ... + E '' m · W 'm) / (W' 1 + W '2 + ... W' m) (5)

(However, ethylene-unsaturated carboxylic acid (derivative) copolymer 1, ethylene-unsaturated carboxylic acid (derivative) copolymer 2, ... ethylene-unsaturated carboxylic acid (derivative) copolymer m m ethylene-unsaturated car It is said that the carboxylic acid (derivative) copolymer is used in combination (m is an integer of 2 or more), and the content of the monomer unit derived from ethylene in the ethylene-unsaturated carboxylic acid (derivative) copolymer k is E'' _k , the resin composition. and the content of copolymer of k to W _'k (k is an integer from 1 to m).)

The melt flow rate (MFR) of the ethylene-unsaturated carboxylic acid (derivative) copolymer is preferably 0.1 g/10 min or more and 10 g/10 min or less from the viewpoint of processing into a film. The MFR is measured according to JIS K 7210:1999 under the method A under conditions of a temperature of 190°C and a load of 21.18 N.

The density of the ethylene-unsaturated carboxylic acid (derivative) copolymer is 930 kg/m 3 or more and 950 kg/m 3 or less, more preferably 935 kg/m from the viewpoint of increasing light scattering properties in the summer reaching 40°C. It is ㎥ or more and 945 ㎏/㎥ or less. In addition, the density of the ethylene-unsaturated carboxylic acid (derivative) copolymer in this invention is a value measured according to the method prescribed|regulated to JIS K 6760-1981. When the density is less than 930 kg/m 3 or greater than 950 kg/m 3, light scattering (haze value) at around 40° C. is difficult to obtain, which is not preferable.

When two or more types of ethylene-unsaturated carboxylic acid (derivative) copolymers are used together as an ethylene-unsaturated carboxylic acid (derivative) copolymer, the density (d') of the copolymer is calculated by the following formula (6). .

d'(㎏/㎥) =

_{(d '1 · W' 1} + d '2 · W' 2 + ... + d 'm · W' m) / (W '1 + W' 2 + ... W 'm) (6)

(However, ethylene-unsaturated carboxylic acid (derivative) copolymer 1, ethylene-unsaturated carboxylic acid (derivative) copolymer 2, ... ethylene-unsaturated carboxylic acid (derivative) copolymer m m ethylene-unsaturated car It is said that a carboxylic acid (derivative) copolymer is used in combination (m is an integer of 2 or more), and the density (unit: kg/m 3) of the ethylene-unsaturated carboxylic acid (derivative) copolymer k is d′ _k , and ethylene in the resin composition. and in the W _'k (k is an integer from 1 to m)): unsaturated carboxylic acid (derivative) content (㎏) of the copolymer k.

The ethylene-α-olefin copolymer refers to an ethylene-α-olefin copolymer having a monomer unit derived from ethylene and a monomer unit derived from α-olefin as main monomers. The ethylene-α-olefin copolymer may be a random copolymer of an ethylene monomer and an α-olefin monomer, or a block copolymer.

The α-olefin monomer preferably has 3 to 20 carbon atoms, and examples of the ethylene-α-olefin copolymer include ethylene-propylene copolymer, ethylene-1-butene copolymer, and ethylene-1-pentene copolymer. Copolymers, ethylene-1-hexene copolymers, ethylene-1-heptene copolymers, ethylene-1-octene copolymers, and the like. Of these, ethylene-1-butene copolymer, ethylene-1-hexene copolymer, and ethylene-1-octene copolymer are particularly preferred. Moreover, you may use what copolymerized ethylene and 2 or more types of alpha-olefins as an ethylene-alpha-olefin copolymer.

The ethylene-α-olefin copolymer contributes to providing a film having excellent strength. From the viewpoint of obtaining a high strength film, the ethylene-α-olefin copolymer is preferably one in which ethylene and α-olefin are polymerized using a metallocene catalyst.

The following are mentioned as a commercial item which can be used as said ethylene-α-olefin copolymer. Exylene (registered trademark) FX (manufactured by Sumitomo Chemical Co., Ltd.), Tafmer (registered trademark) (Mitsui Chemical Co., Ltd.), ENGAGE (registered trademark) (manufactured by Dow Chemical), AFFINITY (registered trademark) (manufactured by Dow Chemical) , EXACT (registered trademark) (manufactured by ExxonMobil), Canel (registered trademark) (manufactured by Nihon Polyethylene Co., Ltd.).

As the ethylene-α-olefin copolymer, a single ethylene-α-olefin copolymer may be used, or two or more types of ethylene-α-olefin copolymers may be used in combination.

The density of the ethylene-α-olefin copolymer is 860 kg/m 3 or more and 895 kg/m 3 or less, more preferably 865 kg/m 3 or more and 890 kg, from the viewpoint of increasing light scattering properties in the summer reaching 40°C. /㎥ or less. In addition, the density in this invention is a value measured according to the method prescribed|regulated to JIS K 6760-1981.

When two or more types of ethylene-α-olefin copolymers are used in combination as the ethylene-α-olefin copolymer, the density (d'') of the ethylene-α-olefin copolymer is calculated by the following formula (7).

d'' (㎏/㎥) =

(d'' ₁ , W'' ₁ + d'' ₂ , W'' ₂ + ... + d'' _m , W'' _m )/(W'' ₁ + W'' ₂ + ... W'' _m ) (7)

(However, ethylene-α-olefin copolymer 1, ethylene-α-olefin copolymer 2, ... m-type ethylene-α-olefin copolymer of ethylene-α-olefin copolymer m is used together (m is an integer of 2 or more ), the density (unit: kg/m 3) of the ethylene-α-olefin copolymer k is d _k , and the content (unit: kg) of the ethylene-α-olefin copolymer k in the resin composition is W _k (k is Integers from 1 to m).)

The melt flow rate (MFR) of the ethylene-α-olefin copolymer is preferably 0.05 g/10 minutes or more and 20 g/10 minutes or less, more preferably 0.1 g/10 minutes or more and 15 g/10 minutes or less to be. The MFR is measured according to JIS K 7210:1999 under the method A under conditions of a temperature of 190°C and a load of 21.18 N.

The continuous phase may contain, in addition to the thermoplastic resin, at least one additive selected from light stabilizers, ultraviolet absorbers, antifogging agents, antioxidants, antifogging agents, lubricants, and the like, within a range that does not impair the effects of the present invention.

[Distribution phase]

It is preferable that the dispersed phase contains at least one component selected from organic particles, inorganic particles, and thermoplastic resins. Although the refractive index of the component contained in a dispersed phase is not specifically limited, It is preferable that it is 1.44 or more and 1.65 or less, and it is more preferable that it is 1.49 or more and 1.53 or less.

(Organic particles)

Examples of the organic particles include crosslinked acrylic particles. Examples of the crosslinked acrylic particles include crosslinked (meth)acrylic acid ester and styrene crosslinked copolymer particles (crosslinked MMA-St copolymer particles), crosslinked polymethacrylate particles (crosslinked PMMA particles), and the like. Examples of the (meth)acrylic acid ester include methyl acrylate, ethyl acrylate, butyl acrylate, methyl methacrylate, ethyl methacrylate, and butyl methacrylate, and preferably methyl acrylate, methyl methacrylate or methacryl. Butyl acid, More preferably, it is methyl methacrylate.

The crosslinked copolymer particles of (meth)acrylic acid ester and styrene may be crosslinked copolymer particles containing only monomer units derived from (meth)acrylic acid ester and styrene, and other than monomer units derived from (meth)acrylic acid ester and styrene. Crosslinked copolymer particles containing monomer units may be used. In addition, in the crosslinked copolymer particles of (meth)acrylic acid ester and styrene, the content ratio of (meth)acrylic acid ester and monomer unit derived from styrene in all monomer units is preferably 80% by mass or more.

The content of the monomer unit derived from the (meth)acrylic acid ester in the crosslinked copolymer particles of the (meth)acrylic acid ester and styrene is preferably 50 to 99 mass%, more preferably 60 to 90 mass%. . Moreover, the content of the monomer unit derived from styrene in the crosslinked copolymer particles of the (meth)acrylic acid ester and styrene is preferably 1 to 50 mass%, more preferably 10 to 40 mass%. (However, the sum of the monomer units derived from the (meth)acrylic acid ester and the monomer units derived from styrene is 100% by mass.)

The (meth)acrylic acid ester and styrene crosslinked copolymer particles are known methods such as suspension polymerization of a monomer component containing at least one selected from (meth)acrylic acid esters, styrene, and other monomers as necessary. Can be obtained by polymerization.

As a method of obtaining a crosslinked acrylic particle, the method of suspension polymerization of a monomer component with a crosslinking agent is mentioned. As a crosslinking agent, it is preferable to use a compound having two or more unsaturated groups, specifically, ethylene glycol dimethacrylate, polyethylene glycol dimethacrylate, trimethylolpropane trimethacrylate, divinylbenzene, etc. Can.

The volume median diameter of the organic particles is preferably 1 µm or more, more preferably 2 µm or more, and even more preferably 3 µm or more from the viewpoint of increasing light scattering properties in the summer reaching 40°C. Moreover, the said volume median diameter is preferably 20 micrometers or less, More preferably, it is 15 micrometers or less, More preferably, it is 10 micrometers or less. The volume median diameter of the organic particles is measured by the Coulter counter method.

The refractive index of the organic particles is 1.500 or more and 1.515 or less. The said refractive index is a value measured using the particle immersion method at room temperature.

Examples of commercially available products of the organic particles include: Techpolymer (registered trademark) MSX series, Techpolymer (registered trademark) SSX series (above, manufactured by Sekisui Chemical Products Co., Ltd.), Art Pearl (registered trademark) G series, Art Pearl ( Registered trademark) GS series (above, manufactured by Negami Industrial Co., Ltd.), Gantz pearl (registered trademark) GSM series (above, manufactured by Aika Industrial Co., Ltd.) and the like.

(Inorganic particles)

Examples of the inorganic particles include glass particles, calcium carbonate, mica, kaolin, aluminosilicate (zeolite), silica, and the like.

Glass particles are particles containing silicon dioxide (SiO ₂ ), boron oxide (B ₂ O ₃ ), aluminum oxide (Al ₂ O ₃ ), sodium oxide (Na ₂ O), calcium oxide (CaO), and oxidation It may contain at least one inorganic compound selected from the group consisting of zinc (ZnO). The glass particles may further contain additional inorganic compounds and additives, if necessary. Specifically, in addition to the inorganic compound, zirconium oxide, magnesium oxide, strontium oxide, lanthanum oxide, yttrium oxide, gadolinium oxide, bismuth oxide, antimony oxide, tantalum oxide, niobium oxide, tungsten oxide, magnesium carbonate, silicon nitride Conventional inorganic compounds such as aluminum nitride, aluminum oxynitride, magnesium fluoride, calcium fluoride, sodium fluoride, lithium fluoride, and iron can be appropriately mixed as necessary, and an agricultural film can be prepared to be within the range of the birefringence.

The shape of the inorganic particles is not particularly limited, and inorganic particles of various shapes, such as spherical (for example, glass beads), fibrous (for example, chopped fiber, milled fiber), and flake, can be used.

When the inorganic particles are spherical, the volume median diameter is preferably 1 µm or more, more preferably 2 µm or more, and still more preferably 3 from the viewpoint of increasing light scattering properties in the summer reaching 40°C. It is more than micrometer. Moreover, the said volume median diameter is preferably 20 micrometers or less, More preferably, it is 15 micrometers or less, More preferably, it is 10 micrometers or less. The volume median of the particles is measured by laser diffraction.

When the inorganic particles are fibrous, the aspect ratio is not particularly limited, but those having an aspect ratio of 1 to 500 are used in view of increasing light scattering properties in the summer reaching 40° C., and having an aspect ratio of 1 to 100 It is more preferably used, and an aspect ratio of 1 to 50 is more preferably used.

In addition, the inorganic particles may be surface-treated with a surface treatment agent such as a coupling agent.

(Thermoplastic resin)

Examples of the thermoplastic resin include non-crosslinked acrylic resins such as methyl methacrylate and methyl methacrylate-phenyl methacrylate, polyvinyl alcohol (PVOH), cyclic olefin copolymer (COC), and the like. Can be heard. In addition, the thermoplastic resin in the dispersed phase is a thermoplastic resin different from the thermoplastic resin in the continuous phase.

The dispersed phase, in addition to at least one selected from organic particles, inorganic particles, and thermoplastic resins, is within the range that does not impair the effects of the present invention, infrared absorbers, light stabilizers, ultraviolet absorbers, antifogging agents, antioxidants, antifogging agents, And at least one additive selected from lubricants and the like.

Examples of the infrared absorber include hydrotalcite compounds and lithium aluminum composite hydroxides. Specific examples of the hydrotalcite compounds include natural hydrotalcite and trade names: DHT-4A (manufactured by Kyowa Chemical Industry Co., Ltd.), Magkria (manufactured by Toda Industry Co., Ltd.), and Magsera (registered trademark) 1 (Kyowa Chemical Industry Co., Ltd. product), STABACE (registered trademark) HT-P (Sakae Chemical Industry Co., Ltd. product), etc. are mentioned. Specific examples of the lithium aluminum composite hydroxide include OPTIMA-SS (manufactured by Toda Industry Co., Ltd.), Mizukarak (registered trademark) (manufactured by Mizuwa Chemical Industry Co., Ltd.), and the like.

In one aspect of the present invention, a hydrotalcite compound may be used alone, or a lithium aluminum composite hydroxide may be used alone. Alternatively, both may be used in combination.

As said light stabilizer, the hindered amine compound which has the structure of Unexamined-Japanese-Patent No. 8-73667 is mentioned, for example. Specifically, product names: Tinuvin (registered trademark) 622, Chimasov (registered trademark) 944, Chimasov (registered trademark) 119 (above BASF), Hostabine (registered trademark) N30, Hostabine (registered trademark) ) PR-31 (above Clariant), Saiyasorb (trademark) UV3529, Saiyasorb (trademark) UV3346 (above Saitec).

Furthermore, the hindered amine compound which has the structure described in Unexamined-Japanese-Patent No. Hei 11-315067, Unexamined-Japanese-Patent No. 2001-139821, WO2005/082852, and Unexamined-Japanese-Patent No. 2009-530428 is mentioned. Specifically, product names: NOR371 (manufactured by BASF), Adekastab (registered trademark) LA-900 (manufactured by ADEKA Co., Ltd.), Adekastab (registered trademark) LA-81 (manufactured by ADEKA Co., Ltd.), hostavin (registered trademark) NOW (made by Clariant Co., Ltd.) is mentioned.

Moreover, as a light stabilizer, the ethylene-cyclic aminovinyl compound copolymer which has a monomer unit based on ethylene and a cyclic aminovinyl compound is also mentioned. As such an ethylene-cyclic aminovinyl compound copolymer, what has a structure described in JP 2002-265693 A is mentioned.

The content of the light stabilizer contained in the resin composition constituting the layer composed of the continuous phase and the dispersed phase is preferably 0.01 to 3% by mass, more preferably 0.05 to 2% by mass, and particularly preferably 0.1 to 1% by mass. However, the mass of the resin composition is 100 mass%.

Examples of the ultraviolet absorber include 2-hydroxybenzophenones, 2-(2'-hydroxyphenyl)benzotriazoles, benzoates, substituted oxanilides, cyanoacrylates, and triazines. Can be lifted.

Examples of 2-hydroxybenzophenones include 2,4-dihydroxybenzophenone, 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-octoxybenzophenone, and 5,5 '-Methylenebis(2-hydroxy-4-methoxybenzophenone), and the like.

As 2-(2'-hydroxyphenyl)benzotriazoles, 2-(2'-hydroxy-5'-methylphenyl)benzotriazole, 2-(2'-hydroxy-3',5'-di Tert-butylphenyl)benzotriazole, 2-(2'-hydroxy-3',5'-di tert-butylphenyl)-5-chlorobenzotriazole, 2-(2'-hydroxy-3'- Tert-butyl-5'-methylphenyl)-5-chlorobenzotriazole, 2-(2'-hydroxy-5'-tertiary octylphenyl)benzotriazole, 2-(2'-hydroxy-3', 5'-dicumylphenyl)benzotriazole, 2-(2-hydroxy-3,5-di tertiary pentylphenyl)benzotriazole, 2,2'-methylenebis(4-tertiary octyl-6-benzo Triazolyl)phenol, 2-(2'-hydroxy-3'-tertbutyl-5-carboxyphenyl)benzotriazole, and the like.

Examples of benzoates include phenyl salicylate, resorcinol monobenzoate, 2,4-di tertiary butylphenyl-3',5'-di tertiary butyl-4'-hydroxybenzoate, 2,4 -Di- tert-amylphenyl-3',5'-di tert-butyl-4'-hydroxybenzoate, hexadecyl-3,5-di tert-butyl-4-hydroxybenzoate, etc. are mentioned.

2-ethyl-2'-ethoxyoxanilide, 2-ethoxy-4'-dodecyloxanilide, etc. are mentioned as a substituted oxanilide.

Examples of the cyanoacrylates include ethyl-α-cyano-β,β-diphenylacrylate, methyl-2-cyano-3-methyl-3-(p-methoxyphenyl)acrylate, and the like. have.

As triazines, 2-(4,6-diphenyl-1,3,5-triazin-2-yl)-5-[(hexyl)oxy]-phenol, 2-[4,6-bis(2 ,4-dimethylphenyl)-1,3,5-triazin-2-yl]-5-(octyloxy)phenol, 2-(2-hydroxy-4-octoxyphenyl)-4,6-bis( 2,4-di tert-butylphenyl)-s-triazine, 2-(2-hydroxy-4-methoxyphenyl)-4,6-diphenyl-s-triazine, 2-(2-hydroxy And -4-propoxy-5-methylphenyl)-4,6-bis(2,4-di tert-butylphenyl)-s-triazine.

Preferably it is 2-(2'-hydroxyphenyl)benzotriazoles, More preferably, 2-(2'-hydroxy-3'-tert-butyl-5'-methylphenyl)-5-chlorobenzo Triazole, 2-(2-hydroxy-3,5-di tertiary pentylphenyl)benzotriazole.

The ultraviolet absorbers are used alone or in combination of two or more. As for content of the ultraviolet absorber contained in the resin composition which comprises the layer which consists of a continuous phase and a disperse phase, 0.001-3 mass% is preferable, and 0.005-1 mass% is more preferable. However, the mass of the resin composition is 100 mass%.

Examples of the anti-fogging agent include sorbitan fatty acid esters such as sorbitan monopalmitate, sorbitan monostearate, sorbitan monomonate, sorbitan monooleate and sorbitan dioleate, and sorbents such as alkylene oxide adducts thereof. Non-surfactant, glycerin monopalmitate, glycerin monostearate, diglycerin distearate, triglycerin monostearate, tetraglycerin dimonate, glycerin monooleate, diglycerin monooleate, diglycerin sesquioleate , Glycerin fatty acid esters such as tetraglycerin monooleate, hexaglycerin monooleate, hexaglycerin trioleate, tetraglycerin trioleate, tetraglycerin monolaurate, hexaglycerin monolaurate, and alkylene oxide adducts thereof Polyethylene glycol surfactants such as glycerin surfactant, polyethylene glycol monopalmitate, polyethylene glycol monostearate, alkylene oxide adduct of alkylphenol, ester of sorbitan/glycerin condensate with organic acid, polyoxyethylene (2 mol ) Stearylamine, polyoxyethylene (4 mol) stearylamine, polyoxyethylene (2 mol) stearylamine monostearate, polyoxyethylene (4 mol) laurylamine monostearate, and other polyoxyethylene alkylamines And nonionic surfactants such as fatty acid esters thereof. These may be used alone or in combination of two or more.

Examples of the antioxidant include trivalent phosphorus atoms such as so-called hindered phenol compounds such as 2,6-dialkylphenol derivatives and 2-alkylphenol derivatives, and phosphite compounds and phosphonite compounds. And phosphorus-based ester compounds. These antioxidants may be used alone or in combination of two or more. In particular, from the viewpoint of color stabilization, it is preferable to use a hindered phenol compound and a phosphorus ester compound in combination.

Examples of the antifogging agent include fluorine compounds having a perfluoroalkyl group, ω-hydrofluoroalkyl group, etc. (especially fluorine-based surfactants), and silicone-based compounds having alkylsiloxane group (especially silicone-based surfactants) and the like. . Specific examples of the fluorine-based surfactant include Unidyne (registered trademark) DSN-403N, DS-403, DS-406, DS-401 (trade name) manufactured by Daikin Industries, Ltd., and Saffron manufactured by AGC Seimi Chemical Co., Ltd. ( Trademarks) KC-40, AF-1000, AF-2000 (trade name), and the like, and examples of silicone-based surfactants include SH-3746 (trade name) manufactured by Dore Dow Corning Co., Ltd. These may be used alone or in combination of two or more. The content of the anti-fogging agent contained in the resin composition constituting the layer consisting of the continuous phase and the dispersed phase is preferably 0.01 to 3% by mass, more preferably 0.02 to 2% by mass, and particularly preferably 0.05 to 1% by mass. However, the mass of the resin composition is 100 mass%.

<Other floors>

The agricultural film according to one embodiment of the present invention may be a film having only a layer composed of a continuous phase and a dispersed phase, or a film having a layer other than a layer composed of a continuous phase and a dispersed phase. As one of the preferred forms of the film of the present invention, a multilayer film in which an intermediate layer composed of a continuous phase and a dispersed phase is present between two polyolefin-based resin layers is mentioned. By this layer structure, the advantage that the strength of the film can be improved is obtained.

The two polyolefin-based resin layers in the multilayer film may be the same or different. As the structure of the multi-layer film, more specifically, 2 types 3 layers, 3 types 3 layers, 3 types 4 layers, 4 types 4 layers, 4 types 5 layers, 5 types 5 layers, and the like can be exemplified.

When the multilayer film is composed of four or more types of layers, both the continuous phase and the dispersed phase layer and the polyolefin-based resin layer may have different layers, or may have three or more polyolefin-based resin layers. Moreover, two or more layers may be formed of a continuous phase and a dispersed phase.

For example, when the polyolefin-based agricultural film is a 5-layer film, C/A/B/ when the polyolefin-based resin layer is A, and the intermediate layer composed of the continuous phase and the dispersed phase is different from B, A, and B as C. Any of A/C, A/B/A/C/C, A/A/B/A/A, A/A/B/B/A, A/B/A/B/A may be used.

Moreover, when the film related to one aspect of the present invention is a multi-layered film composed of three layers, the ratio of the thickness of each layer is a polyolefin-based system from the viewpoint of balance of light scattering property and light transmittance at around 40°C and strength of the film. It is preferable that the layer/polyolefin resin layer which consists of a resin layer/continuous phase and a dispersed phase is 1/2/1 to 1/4/1.

The polyolefin-based resin layer contains a polyolefin-based resin. As a polyolefin resin, high pressure method low density polyethylene; High density polyethylene; Ethylene-based copolymers such as ethylene-1-butene copolymer and ethylene-1-hexene copolymer; And ethylene-unsaturated carboxylic acid ester copolymers such as ethylene-methyl acrylate copolymer and ethylene-methyl methacrylate copolymer. As for these polyolefin-type resins, only 1 type may be used and 2 or more types may be used together.

The polyolefin-based resin layer may contain a light stabilizer, an ultraviolet absorber, an antifogging agent, an antioxidant, an antifogging agent, a lubricant, an anti-blocking agent, an antistatic agent, a pigment, etc., if necessary. In that it does not contain a combination of ethylene-based copolymers, it can be distinguished from a layer made of a resin composition.

The film according to one aspect of the present invention may have an antifogging coating film layer on one surface or on both surfaces. Examples of the antifogging coating layer include an antifogging layer made of an inorganic colloid, and an antifogging coating layer containing an inorganic colloid and a binder resin.

The inorganic colloid imparts hydrophilicity to the surface of the hydrophobic polyolefin-based resin film, and is usually used in the form of a sol in which the inorganic colloid is dispersed in a liquid dispersion medium such as water. Specifically, a silica sol and an alumina sol are mentioned, and a silica sol is preferable.

Examples of the binder resin include polyurethane-based resins, acrylic-based resins, acrylic-modified polyurethane-based resins, polyester-based resins, and epoxy-based resins.

The binder resin is usually used as an aqueous emulsion in which the resin is dispersed in a mixed solvent of water, an aqueous solvent such as water and alcohol.

The antifogging coating layer is preferably an antifogging layer containing silica and a binder resin. Further, as the binder resin, polyurethane-based resins, acrylic-based resins, and acrylic-modified polyurethane-based resins are preferable.

As a preferable silica, the spherical thing whose average particle diameter is 5-100 nm is mentioned.

When the total of the silica and the binder resin contained in the antifogging coating layer is 100 mass%, the content of the silica is preferably 30 to 70 mass%, the content of the binder resin is preferably 30 to 70 mass%, and the content of silica It is 50-65 mass %, and it is more preferable that content of binder resin is 35-50 mass %. When the content of silica is too small, a sufficient anti-fogging effect is not obtained. On the contrary, when the content is too large, the film becomes cloudy and the light transmittance under low temperature can be reduced.

An antifogging coating film layer containing silica and a binder resin can be formed, for example, as shown below. An aqueous emulsion containing a binder resin, an aqueous silica sol containing silica, and water as a dispersion medium are mixed and stirred to obtain a coating solution. Next, the anti-fogging layer can be formed by applying this coating solution using a known means and drying it. Specific examples of the application means include bar coating, gravure coating, reverse coating, brush coating, spray coating, kiss coating, die coating, dipping and the like. As a drying means, hot air drying is mentioned, for example.

The thickness of the coating film made of silica and a binder resin is preferably 0.3 to 1.5 µm, more preferably 0.5 to 1.2 µm.

In order to improve coating property, the said coating liquid can contain a silicone type surfactant and a fluorine type surfactant. As a silicone surfactant, polyether-modified silicone oil is mentioned, for example.

Moreover, you may add a crosslinking agent, a light stabilizer, and an ultraviolet absorber to the said coating liquid as needed.

The antifogging coating layer may be formed as one surface layer of the film, or may be formed as both surface layers. Moreover, the anti-fogging layer may be a single layer film or a multilayer film of two or more layers.

<Method of manufacturing agricultural film>

It is preferable that the manufacturing method of the agricultural film of this invention contains the film forming process of forming a resin composition by the inflation method. The resin composition constituting the layer composed of the continuous phase and the dispersed phase is as described above in <Agricultural Film>.

The manufacturing method of the agricultural film of this invention may further include the mixing process of mixing a resin composition before a film forming process.

As a method of mixing the resin composition, for example, a method of mixing the resin composition in a mixer such as a ribbon blender, a Banbury mixer, a super mixer, or a twin-screw kneader is exemplified.

The extrusion temperature is preferably 130°C or more and 200°C or less, and more preferably 140°C or more and 180°C or less. In addition, in this specification, an extrusion temperature means the temperature of the extruder of the layer which consists of a continuous phase and a dispersed phase, and the layer other than the layer which consists of a continuous phase and a dispersed phase, and the dies.

In the film forming step, a film for agricultural purposes having a birefringence (Δn) of 1.15 × 10 ^-3 or less can be produced by appropriately adjusting BUR, take-off speed, and the like to form a resin composition by an inflation method. When the birefringence (Δn) is greater than 1.15 × 10 ^-3 , the BUR can be made small by increasing the BUR and slowing down the take-up speed. In addition, BUR is also called blow ratio and blow up ratio, and is the ratio of the width of the cut film to the TD direction of the perimeter of the die.

<Farming and Gardening Facilities>

Since the agricultural film according to one embodiment of the present invention can be preferably prevented from being ruptured when the agricultural film is caught in the agricultural horticultural facility frame for electric field farming in the agricultural horticultural facility. , Its handling is very easy. Therefore, using the agricultural film according to one embodiment of the present invention, a method for electric field farming facilities, and agricultural and horticultural facilities extended using agricultural film are also the scope of the present invention.

In addition, in the agricultural horticultural facility covered with the agricultural film according to one embodiment of the present invention, since the light scattering property of the film is high in the summer reaching 40°C, it prevents obstacles such as leaf burning of crops caused by excessive direct sunlight. can do. The farming and gardening facility is preferably used for cultivation of spinach, tomato, green onion, cucumber, strawberry, and the like.

As an agricultural horticultural facility provided with an agricultural film related to one embodiment of the present invention, for example, a greenhouse for plant cultivation, a tunnel, and the like can be mentioned. In the agricultural and horticultural facility, the agricultural film is, for example, mounted on the agricultural and horticultural facility frame.

(Example)

Hereinafter, examples of the present invention are shown. In addition, the test methods in Examples and Comparative Examples are as follows.

[Test Methods]

<birefringence>

The birefringence ((DELTA)n) was measured with the following method about arbitrary five points in a film, and the average value was made into the birefringence of a film.

Using a phase difference measuring device (manufactured by Oji Scientific Instruments Co., Ltd., KOBRA-WPR), the directions of the slow axis and the slow axis of the film at a wavelength of 586 nm and the values of in-plane retardation (Re) were obtained, and the birefringence ( Δn) was calculated.

Δn (birefringence) = Re/D (total thickness)

<The ratio of the area of the cross section of the dispersed phase of 1 μm or more and 10 μm or less in a circle equivalent diameter to the area of the cross section of the intermediate layer>

The film was cut in a direction perpendicular to the film surface and in a direction parallel to the slow axis in the film plane obtained using the retardation measuring device. Using an optical microscope (Nikon Corporation, ECLIPSE (registered trademark) LV100DA-U), the observation magnification was 500 times, and images of arbitrary two points on the cross section of the film were acquired. The length in the direction parallel to the slow axis of the cross-sectional image of the film described in the Examples described later was 238 µm corresponding to actual dimensions.

Next, using an image analysis system (manufactured by Nireco Co., Ltd., LUZEX (registered trademark)-AP), in a cross-sectional image of a film, a disperse phase having an equivalent diameter of 1 µm or more and 10 µm or less with respect to the area of the cross-section of the intermediate layer The ratio of the area of the cross section (hereinafter, sometimes referred to as a dispersion phase ratio of 1 µm or more and 10 µm or less) is obtained. Disperse phase ratios of 1 µm or more and 10 µm or less of the original equivalent diameter were obtained for the cross-sectional images of the two points, and the average value was defined as the ratio of the disperse phases of 1 µm or more and 10 µm or less.

<Haze value>

The temperature was measured at 40 degreeC using the Onzo Haze Meter (THM-150TL) manufactured by Murakami Color Technology Research Institute. Measurement conditions other than temperature were in accordance with JIS K 7136:2000.

<Elongation at tensile break in MD direction>

AGS-100B manufactured by Shimadzu Corporation was used to measure at 23°C and a tensile rate of 500 mm/min. Measurement conditions other than that were in accordance with JIS K 6732-1981.

[material]

Below, the materials used are shown.

In addition, the MFR described below corresponds to the value measured by the method A under the conditions of temperature 190°C and load 21.18 N according to JIS K 7210:1999.

Ethylene copolymer:

(1) Ethylene-vinyl acetate copolymer (EVA) (hereinafter referred to as EVA-1)

Density 952 ㎏/㎥

MFR (190°C, 21.18 N) 7 g/10 min

Content of monomer unit derived from ethylene 72 mass%, content of monomer unit derived from vinyl acetate (VA) 28 mass% (mass of EVA-1 is 100 mass%)

(Sumitate (registered trademark) KA-30 Sumitomo Chemical Co., Ltd.)

(2) Ethylene-vinyl acetate copolymer (EVA) (hereinafter referred to as EVA-2)

Density 935 ㎏/㎥

MFR (190°C, 21.18 N) 1.5 g/10 min

Content of monomer unit derived from ethylene 85 mass%, content of monomer unit derived from vinyl acetate (VA) 15 mass% (mass of EVA-2 is 100 mass%)

(Evatate (registered trademark) H2020 Sumitomo Chemical Co., Ltd.)

(3) Ethylene-1-octene copolymer (POE) (hereinafter referred to as POE-1)

Density 890 ㎏/㎥

MFR (190°C, 21.18 N) 1 g/10 min

(ENGAGE (registered trademark) 8003 Dow Chemical)

Polyolefin resin:

(1) Polyethylene resin (PE(EPPE)) (hereinafter referred to as PE-1)

Density 912 ㎏/㎥

MFR (190°C, 21.18 N) 0.5 g/10 min

(Exeren (registered trademark) GMH GH030 manufactured by Sumitomo Chemical Co., Ltd.)

(2) Linear low density polyethylene resin (LLDPE) (hereinafter referred to as PE-2)

(3) Polyethylene resin (PE(EPPE)) (hereinafter referred to as PE-3)

Density 921 ㎏/㎥

MFR (190°C, 21.18 N) 0.4 g/10 min

(Exeren (registered trademark) GMH GH051 Sumitomo Chemical Co., Ltd.)

particle :

(1) Crosslinked methyl methacrylate-styrene copolymer particles (hereinafter referred to as Particle-1)

Volume median diameter = 5 μm

Refractive index (23 ℃) = 1.51

(Techpolymer (registered trademark) MSX-5Z Sekisui Chemicals Co., Ltd.)

(2) Calcium carbonate (hereinafter referred to as Particle-2)

(3) OMicron (registered trademark) NP5-P0 (glass beads manufactured by Sovitec) (hereinafter referred to as Particle-3)

Volume median diameter = 5 μm

Refractive index (23 ℃) = 1.51

The films of Examples 1 to 5 and Comparative Examples 1 to 5 including the polyolefin resin layer/resin composition layer/polyolefin resin layer were prepared and evaluated.

[Example 1]

<production of master batch>

With respect to 100 mass% of the masterbatch, EVA-2 49.2 mass%, particle-1 50 mass%, and antioxidant Irganox (registered trademark) 1010 (manufactured by BASF) 0.8 mass% are used as an intensive mixer (manufactured by Nippon Roll Co., Ltd.). Was fed, mixed at 160°C for 5 minutes, and the obtained mixture was fed to a 65 mmφ single screw extruder (manufactured by Nihon Steel Works Co., Ltd.), extruded, and pelletized to obtain a masterbatch for a resin composition used as an intermediate layer. This masterbatch was referred to as MB-1.

<production of film>

Three-layer inflation molding machine equipped with an inner layer extruder (40 mm extruder), an intermediate layer extruder (40 mm extruder), an outer layer extruder (40 mm extruder), and a 100 mmφ die (lip gap 1.2 mm) (Fura Co., Ltd.) Nose) was used, and a three-layer tube-like film was molded.

Specifically, the material of the polyolefin-based resin composition for the outer layer is put in an extruder for the outer layer, the material of the resin composition of Example 1 is put in the extruder for the intermediate layer, and the material of the polyolefin-based resin composition for the inner layer is put in the extruder for the inner layer. Then, after melt-kneading in each extruder, the discharge amount was adjusted so that the inner layer was 20 µm, the middle layer was 60 µm, and the outer layer was 20 µm (total thickness of 100 µm) from the 100 mmφ dies, and the resin of each molten layer. The composition was extruded and cooled to form a three-layer tubular film, incised with BUR 2.1, drawn at a take-up rate of 4.1 m/min, and a three-layer multilayer film was obtained. At this time, the extruders of the inner layer, the middle layer, and the outer layer, and the dice were set at 140°C.

Moreover, the material of the polyolefin resin composition for outer layers was 100 mass% of PE-1. Moreover, the material of the resin composition for intermediate layers of Example 1 is EVA-1 and MB-1, and the compounding amount is EVA-1 is 30 mass%, EVA-2 is 40 mass%, and MB-1 is 30 It was mass%. The material of the polyolefin resin composition for inner layers was made the same as the material of the polyolefin resin composition for outer layers.

Table 1 shows the birefringence of the obtained film, the disperse phase ratio of 1 μm to 10 μm, and the haze value at 40° C. and the tensile elongation at break in the MD direction.

[Example 2]

Resin compositions and films were obtained in the same manner as in Example 1 except that the extruders of the inner layer, the middle layer, and the outer layer and the dice were set at 150°C. Table 1 shows the birefringence of the obtained film, the disperse phase ratio of 1 μm to 10 μm, and the haze value at 40° C. and the tensile elongation at break in the MD direction.

[Example 3]

A resin composition and a film were obtained in the same manner as in Example 1 except that the take-up speed was 4.2 m/min, the inner layer, the middle layer, and the extruders of the outer layer and the dice were set at 160°C. Table 1 shows the birefringence of the obtained film, the disperse phase ratio of 1 μm to 10 μm, and the haze value at 40° C. and the tensile elongation at break in the MD direction.

[Example 4]

<master placement>

A masterbatch consisting of 40% by mass of PE-2 and 60% by mass of calcium carbonate was used. This masterbatch was referred to as MB-2.

<production of film>

The material of the polyolefin resin composition for an outer layer was PE-1 and PE-3, and the blending amount was 50% by mass of PE-1 and 50% by mass of PE-3. Moreover, the material of the resin composition for intermediate layers of Example 4 was PE-1 and MB-2, and the compounding quantity was 92 mass% of PE-1 and 8 mass% of MB-2. The material of the polyolefin resin composition for inner layers was made the same as the material of the polyolefin resin composition for outer layers. A resin composition and a film were obtained in the same manner as in Example 2 except for the above.

Table 1 shows the birefringence of the obtained film, the disperse phase ratio of 1 μm to 10 μm, and the haze value at 40° C. and the tensile elongation at break in the MD direction.

[Example 5]

<production of master batch>

With respect to 100 mass% of the masterbatch, EVA-2 49.2 mass%, particle-3 50 mass%, and antioxidant Irganox (registered trademark) 1010 (manufactured by BASF Corporation) 0.8 mass% are used as an intensive mixer (manufactured by Nippon Roll Co., Ltd.). Was fed, mixed at 160°C for 5 minutes, and the obtained mixture was fed to a 65 mmφ single screw extruder (manufactured by Nihon Steel Works Co., Ltd.), extruded, and pelletized to obtain a masterbatch for a resin composition used as an intermediate layer. This masterbatch was referred to as MB-3.

<production of film>

The material of the resin composition for an intermediate layer of Example 5 is EVA-2, POE-1, and MB-3, and the blending amount is 10% by mass of EVA-2, 40% by mass of POE-1, and MB-3 It was 50 mass %. A resin composition and a film were obtained in the same manner as in Example 4 except for the above.

Table 1 shows the birefringence of the obtained film, the disperse phase ratio of 1 μm to 10 μm, and the haze value at 40° C. and the tensile elongation at break in the MD direction.

[Comparative Example 1]

A resin composition and a film were obtained in the same manner as in Example 1 except that BUR was 1.4 and the take-up speed was 6.4 m/min. Table 1 shows the birefringence of the obtained film, the disperse phase ratio of 1 μm to 10 μm, and the haze value at 40° C. and the tensile elongation at break in the MD direction.

[Comparative Example 2]

A resin composition and a film were obtained in the same manner as in Example 2 except that BUR was 1.4 and the take-up speed was 6.4 m/min. Table 1 shows the birefringence of the obtained film, the disperse phase ratio of 1 μm to 10 μm, and the haze value at 40° C. and the tensile elongation at break in the MD direction.

[Comparative Example 3]

A resin composition and a film were obtained in the same manner as in Example 3, except that BUR was 1.4 and the take-up speed was 6.3 m/min. Table 1 shows the birefringence of the obtained film, the disperse phase ratio of 1 μm to 10 μm, and the haze value at 40° C. and the tensile elongation at break in the MD direction.

[Comparative Example 4]

A resin composition and a film were obtained in the same manner as in Example 4 except that BUR was 1.4 and the take-up speed was 6.1 m/min. Table 1 shows the birefringence of the obtained film, the disperse phase ratio of 1 μm to 10 μm, and the haze value at 40° C. and the tensile elongation at break in the MD direction.

[Comparative Example 5]

A resin composition and a film were obtained in the same manner as in Example 5 except that BUR was 1.4 and the take-up speed was 6.4 m/min. Table 1 shows the birefringence of the obtained film, the disperse phase ratio of 1 μm to 10 μm, and the haze value at 40° C. and the tensile elongation at break in the MD direction.

The agricultural film according to the present invention can be suitably used as a covering material in agricultural horticultural facilities such as greenhouses and tunnels for plant cultivation.

Claims (2)

An agricultural film having at least one layer composed of a continuous phase and a dispersed phase and satisfying the following (A) and (B);
(A) In the cross section cut in the direction perpendicular to the film surface and parallel to the slow axis in the film surface, the ratio of the area of the cross section of the dispersed phase having a circular equivalent diameter of 1 μm or more and 10 μm or less among the dispersed phases is 1% or more and 30% or less of the area of the cross section of the layer,
(B) The birefringence (Δn) is 1.15 × 10 ^-3 or less. An agricultural horticultural facility in which the agricultural film according to claim 1 is transferred to an agricultural horticultural facility frame.