JP4225521B2 - Agricultural multilayer film - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an agricultural multilayer film covering a house or a tunnel. More specifically, the present invention relates to an agricultural multilayer film capable of maintaining excellent antifogging properties when stretched in a house or tunnel while having toughness.
[0002]
[Prior art]
Various plastic films are used as covering materials for facility horticulture such as agricultural houses and tunnels. Typical examples thereof include a polyvinyl chloride film (hereinafter referred to as “Nongbi”), a polyethylene film (hereinafter referred to as “Nongpoly”), an ethylene vinyl acetate copolymer film (hereinafter referred to as “Nongbi”), and the like. Can be mentioned. Among them, agricultural bean is most frequently used because it is excellent in heat retention, transparency, toughness, anti-fogging property, house adhesion and economy.
[0003]
However, the agricultural bean has a defect that the additive contained in the film gradually oozes out on the film surface, thereby causing stickiness on the film surface and deteriorating workability and dust resistance. In addition, the problem that harmful gases are generated when agricultural beans are incinerated and discarded has been taken up, and agricultural substitutes that do not generate harmful gases are desired.
[0004]
On the other hand, Agricultural Poly and Agricultural Vinegar are superior to Agricultural Bi in terms of workability, dust resistance and ease of disposal, but inferior in heat retention, toughness, anti-fogging properties, etc. Improvements have been desired.
[0005]
Japanese Patent Application Laid-Open No. 60-104141 discloses a technique for adding a specific inorganic filler in order to improve the heat retention of these agricultural poly and agricultural vinegar. In order to improve anti-fogging properties and toughness, Japanese Patent Application Laid-Open No. 58-90960 discloses a multilayer film in which a linear low density polyethylene is used as an outer layer (a layer in contact with the outside air of a house or tunnel), and an intermediate layer is used. Proposal of ethylene-vinyl acetate copolymer, olefin-vinyl alcohol copolymer, laminated film for agriculture using linear low density polyethylene or ethylene vinyl acetate copolymer for inner layer (layer in contact with air inside house or tunnel) Has been.
[0006]
However, although the heat retaining property is improved in the agricultural film using these techniques, the toughness is insufficient as compared with the agricultural film. In recent years, development of linear low density polyethylene which is an ethylene-α-olefin copolymer by polymerization using a single site catalyst instead of the conventional multisite catalyst has progressed, and Japanese Patent Application Laid-Open Nos. 09-052332 and 08-276542. Agricultural multilayer film using an ethylene-α-olefin copolymer obtained by polymerization using a single site catalyst is proposed in Japanese Patent Publication No. JP-A.
[0007]
However, although these agricultural films have improved toughness, the use of an ethylene-α-olefin copolymer by polymerization using a single-site catalyst for the inner and outer layers is sufficient to exhibit antifogging and fog resistance. In addition, despite the large amount of antifogging agent and antifogging agent added, the antifogging property and antifogging durability were insufficient.
[0008]
[Problems to be solved by the invention]
An object of the present invention is to provide an agricultural multilayer film that has excellent toughness but also exhibits good antifogging and antifogging properties and is excellent in antifogging and antifogging durability. There is.
[0009]
As a result of intensive studies to improve the problems of the prior art, the present inventors have found that each layer has a specific composition and is composed of at least an inner layer A, an intermediate layer B, and an outer layer C. Has found that the above-mentioned problems can be improved, and has completed the present invention based on this finding.
[0010]
[Means for Solving the Problems]
The present invention has the following configuration.
(1) An agricultural multilayer film composed of at least an inner layer A, an intermediate layer B and an outer layer C, wherein the inner layer A is mainly composed of an ethylene-vinyl acetate copolymer having a vinyl acetate content of 2 to 10% by weight. The intermediate layer B is composed of an ethylene-α-olefin copolymer (b) having a density (d _b ) of 0.87 to 0.92 g / cm ³ polymerized using a single site catalyst. It is composed of a composition containing 1 to 10% by weight of an antifogging agent as a main component, and the outer layer C is polymerized using a single site catalyst (d _c ) 0.89 to 0.95 g / cm ³ to the configured ethylene -α- olefin copolymer (c) from a composition mainly composed, and, d _b <d _c der is, an inner layer a, the composition constituting the intermediate layer B and the outer layer C , inorganic filler having a BET specific surface area of 5 to 50 m ² / g, but it 0.05 to 5% by weight, 1 to 10% by weight and 1 to 10% by weight are added, and the addition amount of the inorganic filler to the composition constituting the outer layer C is more than the addition amount to the composition constituting the inner layer A Many agricultural multilayer films.
(2) The antifogging agent used in the composition constituting the intermediate layer B is one or more selected from the group of compounds represented by the following formula 1 and neutralized salts thereof with organic acids. The agricultural multilayer film as described in (1) above.
[0011]
[Chemical formula 2]
[0012]
(3) The agricultural multilayer film according to (1) or (2), wherein the multilayer film has a tensile modulus of 1000 to 2000 kgf / cm ² .
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the agricultural multilayer film according to the present invention will be described in detail.
The agricultural multilayer film of the present invention comprises an ethylene-vinyl acetate copolymer, an ethylene-α-olefin copolymer (b) and (c), and one or more of an antifogging agent and an inorganic filler. It is a multilayer film of 3 or more layers composed of a composition as a component. The “main component” of the composition constituting each layer according to the present invention refers to a component contained in the composition at 50% by weight or more.
[0014]
[Ethylene-vinyl acetate copolymer] The ethylene-vinyl acetate copolymer used in the composition constituting the inner layer A in the agricultural multilayer film of the present invention is obtained by reacting ethylene and vinyl acetate by a known high-pressure radical polymerization process. The melt flow rate (hereinafter referred to as MFR) measured by JIS K 7210 is 0.1 to 10 g / 10 min, preferably 0.5 to 5 g / 10 min. If the MFR is less than 0.5 g / 10 min, the moldability of the film, particularly the extrudability and high-speed stretchability may be deteriorated. If the MFR exceeds 5 g / 10 min, the moldability of the film, particularly in inflation molding. Bubble stability may be lacking.
[0015]
The ethylene-vinyl acetate copolymer has a vinyl acetate content of 2 to 10% by weight, and if it is less than 2% by weight, the desired antifogging property of the resulting agricultural multilayer film, particularly at low temperatures, is achieved. It cannot be obtained and the anti-fogging sustainability is also lowered. On the other hand, when the content exceeds 10% by weight, the above-mentioned films may be in close contact with each other, or when they are left outdoors, they may be stored by sunlight and the films may be fused.
[0016]
[Ethylene-α-olefin copolymer] Ethylene-α-olefin copolymers (b) and (c) used as main components of the composition constituting the intermediate layer B and the outer layer C in the agricultural multilayer film of the present invention. Is a random copolymer of ethylene and an α-olefin having 3 to 20 carbon atoms, and is copolymerized using a single site catalyst such as a metallocene catalyst.
[0017]
Examples of the α-olefin having 3 to 20 carbon atoms include propylene, 1-butene, 1-pentene, 1-hexene, 4-methyl-1-pentene, 1-octene, 1-decene, 1-dodecene, 1- Examples include tetradecene, 1-hexadecene, 1-octadecene, and 1-eicocene. The content of the α-olefin in the random copolymer is 1 to 45% by weight, preferably 2 to 35% by weight.
[0018]
As the single site catalyst, a combination of a metallocene compound of Group IV or V transition metal of the periodic table such as titanium, zirconium, hafnium, vanadium, and an organoaluminum compound and / or an ionic compound is used.
[0019]
As the metallocene compound, a compound in which at least one cyclopentadienyl group, a substituted cyclopentadienyl group, hydrocarbyl silicon or the like is crosslinked, and a compound in which the cyclopentadienyl group is crosslinked with oxygen, nitrogen, or phosphorus atoms are arranged. Any known metallocene compound as a ligand can be used.
[0020]
Specific examples of these metallocene compounds include dimethylsilyl (2,4-dimethylcyclopentadienyl) (3 ′, 5′-dimethylcyclopentadienyl) zirconium dichloride, dimethylsilyl (2,4-dimethylcyclopentadienyl). Silicon) bridged metallocene compounds such as (enyl) (3 ', 5'-dimethylcyclopentadienyl) hafnium dichloride, ethylenebisindenylzirconium dichloride, ethylenebisindenylhafnium dichloride, ethylenebis (methylindenyl) zirconium dichloride, ethylene Examples thereof include indenyl-based bridged metallocene compounds such as bis (methylindenyl) hafnium dichloride.
[0021]
The organoaluminum compound used in combination with the metallocene compound is a linear or cyclic polymer represented by the general formula — (Al (R) O) _n — (R is a hydrocarbon group having 1 to 10 carbon atoms). Including those partially substituted with a halogen atom and / or an RO group, where n is the degree of polymerization and is 5 or more, preferably 10 or more, and as specific examples, R is methyl, ethyl, isobutyl, respectively. Examples thereof include methylalumoxane, ethylalumoxane, and isobutylethylalumoxane.
[0022]
Furthermore, other organoaluminum compounds include trialkylaluminum, dialkylhalogenoaluminum, sesquialkylhalogenoaluminum, alkenylaluminum, dialkylhydroaluminum, sesquialkylhydroaluminum and the like.
[0023]
As an ionic compound, the general formula [Q] ^{m +} [Y] ^m− (m is an integer of 1 or more)
Q in the formula is a cation component of an ionic compound, and examples thereof include a carbonium ion, a tropylium cation, an ammonium cation, an oxonium cation, a sulfonium cation, and a phosphonium cation. Y is an anionic component of an ionic compound, which is a component that reacts with a metallocene compound to become a stable anion, and is an organic boron compound anion, an organic aluminum compound anion, an organic gallium compound anion, an organic phosphorus compound anion, an organic Examples include arsenic compound anions and organic antimony compound anions.
[0024]
A known polymerization method is used as a copolymerization method of ethylene and α-olefin using a single site catalyst, and examples thereof include a gas phase polymerization method, a slurry polymerization method, and a solution polymerization method.
[0025]
The ethylene-α-olefin copolymer polymerized by a single site catalyst has a narrow molecular weight distribution and a high α-olefin content compared with the case of copolymerization using a multisite catalyst such as a conventional Ziegler-Natta catalyst. Even those with a high content are copolymerized uniformly, and there are many tie molecules between lamellae, so there are few low molecular weight components, excellent blocking resistance, and excellent transparency, impact resistance, and toughness. Have The density of the ethylene-α-olefin copolymer is usually in the range of 0.870 to 0.960 g / cm ³ .
[0026]
In the agricultural multilayer film of the present invention, the density (d _b ) of the ethylene-α-olefin copolymer (b) used in the composition constituting the intermediate layer B is 0.87 to 0.92 g / cm ³ , preferably Is 0.87-0.90 g / cm ³ . When the density (d _b ) exceeds 0.92 g / cm ³ , the film has a high tensile elastic modulus and lacks flexibility, so that it is difficult to handle the film. Workability at the time of collection is deteriorated. Furthermore, since the adhesion to the house or tunnel is poor, the airtightness cannot be maintained, and the heat retention that is originally required is reduced. Moreover, when the density (d _b ) is less than 0.87 g / cm ³ , the film forming processability is inferior, which is not preferable.
[0027]
In agricultural multi-layer film of the present invention, the density of the ethylene -α- olefin copolymer used in the composition constituting the outer layer C _(c) (d c) is 0.89~0.95g / cm ^3, preferably Those in the range of 0.90 to 0.92 g / cm ³ are preferably used. When the density (d _c ) is less than 0.89 g / cm ³ , the melting point of the ethylene-α-olefin copolymer (c) is lowered, and the films obtained from the composition using the same tend to be in close contact with each other during the stretching. Inferior workability, and problems such as fusion by receiving sunlight when left outdoors. On the other hand, if the density (d _c ) exceeds 0.95 g / cm ³ , the flexibility of the film is inferior, causing poor workability and poor heat retention.
[0028]
In the multilayer film for agriculture of the present invention, it is necessary to use an ethylene-α-olefin copolymer polymerized using a single site catalyst for both the intermediate layer B and the composition constituting the outer layer C. When only one of B and outer layer C is used, the intended toughness cannot be obtained.
[0029]
The density (d _b ) and density (d _c ) must be d _c > d _b . For d _c ≦ d _b, persistent anti-fogging since the anti-fogging agent is rapidly migrate to the outer layer side becomes insufficient.
[0030]
The ethylene-α-olefin copolymers (a) and (b) have a number average molecular weight in the range of 1 × 10 ^{4 to} 100 × 10 ⁴ and a Q value that is a ratio of the weight average molecular weight to the number average molecular weight. Is in the range of 1.5 to 3.5. Further, the MFR under a load condition of 190 ° C. and 2.16 kgf is in the range of 0.2 to 20 g / 10 minutes, and there may be two or more melting peaks by differential scanning calorimetry (DSC). In order to improve transparency and toughness, one is desirable.
[0031]
[Antifogging Agent] In the agricultural multilayer film of the present invention, 1 to 10% by weight of an antifogging agent is added to the composition constituting the intermediate layer B. If it is less than 1% by weight, the antifogging sustaining effect is not sufficient, and if it exceeds 10% by weight, there are problems such as blowing to the surface of the film and the film becoming opaque or foaming during film formation. Arise. The antifogging agent may be added not only to the intermediate layer B but also to each composition constituting the inner layer A or the inner layer A and the outer layer C as required.
[0032]
Examples of the antifogging agent include nonionic surfactants, cationic surfactants, anionic surfactants, amphoteric surfactants, etc., the degree of esterification of the antifogging agent, the chain length of the alkyl group, and the alkylene oxide. Those obtained by changing the number of moles added, or their purity. Examples thereof include partial carboxylic acid esters of polyhydric alcohols such as sorbitan monolaurate, diglycerin sesquilaurate, glycerin monooleate, polyhydric alcohols such as polyoxyethylene sorbitan monolaurate and polyoxyethylene sorbitan monooleate. Examples thereof include polyoxyethylene derivatives of partial carboxylic acid esters, amines and fatty acid amides. Among them, neutralized salts of compounds represented by the following formula 1 and their organic acids are preferably used. Particularly, in the multilayer film for agriculture of the present invention, an ethylene-α-olefin copolymer polymerized by a single site catalyst is used. Even when the polymer was used for the outer layer C and the intermediate layer B, it was revealed that excellent antifogging properties and persistence were exhibited.
[0033]
[Chemical 3]
[0034]
Examples of the compound represented by the above formula 1 include amine compounds such as polyoxyethylene (8 mol) stearylamine, polyoxyethylene (2 mol) laurylamine, polyoxyethylene (2 mol) tallow amine, polyoxyethylene laurylamide Amide compounds such as polyoxyethylene stearylamide, and fatty acid esters of these amine compounds and amide compounds with fatty acids such as lauric acid, stearic acid, behenic acid, and oleic acid. Examples of the organic acid include carboxylic acid, sulfonic acid, phenol carboxylic acid and the like, and among them, carboxylic acid is preferable in terms of reactivity and stability with the compound. Specific examples include lauric acid, stearic acid, behenic acid, oleic acid and benzoic acid.
These antifogging agents are used alone or in combination of two or more.
[0035]
[Inorganic filler] In the agricultural multilayer film of the present invention, it is preferable to add an inorganic filler to the composition constituting the inner layer A, the intermediate layer B and the outer layer C.
In general, in the field of agricultural films, inorganic fillers are used for the purpose of imparting heat retention performance and the purpose of improving the adhesion between the films, but it is possible to control the development of antifogging properties and antifogging durability. .
In the multilayer film for agriculture of the present invention, the amount of the inorganic filler added to the composition constituting the outer layer C is preferably larger than the amount of the inorganic filler added to the composition constituting the inner layer A. As a result, it becomes difficult for the anti-fogging agent and the anti-fogging agent to be deposited on the surface of the outer layer C, and the durability of the anti-fogging and anti-fogging properties increases.
[0036]
The amount of the inorganic filler added to the composition constituting the inner layer A is preferably 0.05 to 5% by weight. The anti-fogging and anti-fogging durability is not sufficient because of the transition, and if it exceeds 5% by weight, the anti-fogging agent and anti-fogging agent are not sufficiently transferred and the anti-fogging and anti-fogging properties are maintained. Not enough. The amount of the inorganic filler added to the composition constituting the intermediate layer B and the outer layer C is preferably 1 to 10% by weight, and if the added amount is less than 1% by weight, it is difficult to retain the antifogging agent and the antifogging agent. Further, the persistence of fog prevention is insufficient, and if it exceeds 10% by weight, mechanical properties and transparency may be lowered.
[0037]
As said inorganic filler, the BET specific surface area measured according to JIS Z 8830 is 5-50 m < ² > / g, Preferably the thing of 5-20 m < ² > / g is used suitably. When the BET specific surface area exceeds 50 m ² / g, the anti-fogging agent and the anti-fogging agent are adsorbed, and the desired anti-fogging performance and anti-fogging performance cannot be obtained. In addition, when it is less than 5 m ² / g, the adsorption to the filler decreases, so that the transfer of the antifogging agent or the antifogging agent to the film surface proceeds rapidly, the film becomes sticky, or the antifogging property or antifogging property is obtained. Sustainability is insufficient.
[0038]
Specific examples of the inorganic filler include silicic acid compounds such as silicon oxide, magnesium silicate, aluminum silicate, and calcium silicate, aluminosilicate compounds such as calcium aluminosilicate, sodium aluminosilicate, and potassium aluminosilicate, alumina, sodium aluminate, and aluminum. Examples thereof include aluminate compounds such as potassium acid and calcium aluminate, calcium carbonate, lithium / aluminum composite hydroxide salts represented by the following formulas 2 and 3 and hydrotalcites represented by the following formula 4 , Alone or in combination of two or more.
[0039]
[Formula 4]
[Al ₂ Li (OH) ₆ ] ₂ (A ⁿ⁻ ) · mH ₂ O—Formula 2
(In the formula, m represents a number of 3 or less.)
[0040]
[Chemical formula 5]
(In the formula, M ²⁺ is a divalent metal, m is a number in the range of 0 ≦ m <5, x is a number in the range of 0 ≦ x <1, y is in the range of 2 ≦ y ≦ 4. Indicates number.)
[0041]
[Chemical 6]
M ²⁺ _1-x Al _x (OH) ₂ (A ⁿ⁻ ) _{x / 2} · mH ₂ O −Formula 4
(Wherein, M ²⁺ is Mg ^2+, Ca ^2+, and represents at least one divalent metal ion selected from among Zn ^2+, A ^n- is an n-valent anion, x and m are (The following conditions are satisfied: 0 <x <0.5, 0 ≦ m ≦ 2)
[0042]
[Other components] In the agricultural multilayer film of the present invention, various materials may be added to the composition constituting the inner layer A, the intermediate layer B, and the outer layer C as long as the object of the present invention is not impaired. In order to improve the film forming processability, a known thermoplastic resin such as a high-pressure low-density polyethylene can be added to the composition constituting each layer. Further, in order to improve flexibility, elastic copolymers such as ethylene-diene elastic copolymers, ethylene-propylene elastic copolymers, styrene-butadiene elastic copolymers polymerized with a single site catalyst or a known multi-site catalyst are used. A polymer may be added. In addition, known hindered amine weathering agents, UV absorbers, antifogging agents (fluorine surfactants), antistatic agents, lubricants, antioxidants, heat stabilizers, antibacterial agents, A pigment | dye, a coloring agent, etc. can be mix | blended.
[0043]
The agricultural multilayer film of the present invention preferably has a tensile strength of 300 kgf / cm ² or more. If the tensile strength is less than 300 kgf / cm ² , the film may be broken by a strong wind, or may be broken when it is pulled with a strong force when it is extended to a house or tunnel. In order to obtain an agricultural multilayer film having a tensile strength of 300 kgf / cm ² or more, ethylene polymerized with a single site catalyst as a main component of the composition constituting the outer layer C and the intermediate layer B of the agricultural multilayer film It is preferable to use an -α-olefin copolymer.
[0044]
In the agricultural multilayer film of the present invention, it is desirable that the tensile elastic modulus is 1000 to 2000 kgf / cm ² . If the tensile modulus is less than 1000 kgf / cm ² , the film tends to stretch due to strong winds and the like, and the adhesion to a house or tunnel may be reduced. If the tensile modulus exceeds 2000 kgf / cm ² , the film is too hard and the adhesion to the house or tunnel is poor, resulting in poor airtightness and heat retention.
In general, in order to improve the workability when spreading and collecting agricultural films to houses and tunnels, and to improve the air tightness and heat retention, the flexibility to agricultural films is improved. It is necessary to give The flexibility of the film can be determined by using the tensile modulus measured according to ASTM D 882 as an index, and the agricultural multilayer film of the present invention has a specific density of ethylene-α-olefin copolymer and ethylene. -By using a vinyl acetate copolymer, it becomes possible to make a tensile elasticity modulus 1000-2000kgf / cm < ² >, and sufficient softness | flexibility is obtained.
[0045]
The thickness of the agricultural multilayer film of the present invention varies depending on the place of use, the service life, etc., but generally about 0.05 to 0.3 mm is preferably used. The thickness Ta of the inner layer, the thickness Tb of the intermediate layer, and the thickness Tc of the outer layer are not particularly limited, but Ta: Tb: Tc is preferably in the range of 1-5: 1 to 5: 1-5.
[0046]
The agricultural multilayer film of the present invention can be produced by a known technique such as an inflation method or a T-die method, and may be subjected to corona discharge treatment for the purpose of improving the antifogging effect after production. Further, in addition to the intermediate layer B, it is a multilayer film of four or more layers in which an intermediate layer D provided with heat retention, an intermediate layer E for improving anti-fogging property, an intermediate layer F containing a recycled material, and the like are laminated. It doesn't matter. Further, a dust-proof coating agent or an anti-fogging coating agent may be applied and dried to form a coating film on the surface.
The multilayer film for agriculture of the present invention may be transparent, pear or semi-pear, and used for mulching purposes other than covering for agricultural houses (greenhouses), tunnels, and bagging. You may do it.
[0047]
【Example】
Hereinafter, the present invention will be specifically described with reference to Examples and Comparative Examples, but the present invention is not limited thereto. In addition, evaluation of the multilayer film for agriculture in an Example and a comparative example was implemented as follows.
[0048]
1) Tensile modulus (Young's modulus): The tensile modulus in the machine direction and the transverse direction of the film sample was measured according to ASTM D882, and the average value of both was shown.
2) Tensile strength: Based on JIS K 7113, the tensile breaking strength in the longitudinal direction and the transverse direction was measured, and the average value of both was shown.
3) low temperature anti-fogging property;
A water bath having a skylight with a tilt of 10 degrees and a diameter of 7.6 cm is used. A film sample is fixed to the skylight of the water bath, and is left for 12 days under conditions of an environmental temperature of 23 ° C and a water temperature of 45 ° C. The sample was allowed to stand for 2 days under the conditions of 15 ° C. and a water temperature, and the antifogging property of the surface of the sample on the water bath side was visually judged based on a five-step standard to evaluate the low temperature antifogging property. The larger the 5-step number, the better the low-temperature antifogging property.
<Evaluation criteria for low-temperature anti-fogging properties>
Evaluation 5: Formation of a uniform water film without adhesion of water droplets.
Evaluation 4: Water droplet adhesion is less than 15%.
Evaluation 3: Adhesion of water droplets is less than 40%.
Evaluation 2: Adhesion of water droplets is less than 65%.
Evaluation 1: Water droplet adhesion is 65% or more.
4) Anti-fogging durability; using a water bath having a skylight with a tilt of 10 degrees and a diameter of 7.6 cm, a film sample is fixed to the skylight of the water bath, and it is day and night under conditions of an environmental temperature of 23 ° C and a water temperature of 45 ° C. The period during which the antifogging property was maintained was visually evaluated. The longer the number of days, the better the antifogging sustainability.
[0049]
The thermoplastic resin used for each layer is shown below. S-LLDPE represents an ethylene-α-olefin copolymer polymerized by a single site catalyst, and M-LLDPE represents an ethylene-α-olefin copolymer polymerized by a multi-site catalyst.
(1) Umerit (trademark) 1520F Ube Industries, Ltd., single site catalyst system ethylene-α-olefin copolymer resin (S-LLDPE)
・ MFR: 2.0 g / 10 min., Density: 0.913 g / cm ³
(2) Umerit (trademark) 0540F Ube Industries, Ltd., single-site catalyst ethylene-α-olefin copolymer resin (S-LLDPE)
・ MFR: 4.0g / 10min., Density: 0.904g / cm ³
(3) NUC3270 Made by Nippon Unicar Co., Ltd. Ethylene vinyl acetate copolymer resin (vinyl acetate content 7.5%) (EVA)
MFR: 2.3 g / 10 min., Density: 0.925 g / cm ³ , tensile modulus: 1300 kgf / cm ²
(4) Petrocene (trademark) 286, manufactured by Tosoh Corporation, ethylene-vinyl acetate copolymer resin (vinyl acetate content 2.0 wt%) (EVA)
MFR: 1.5 g / 10 min., Density: 0.926 g / cm ³ , tensile modulus: 2300 kgf / cm ²
(5) Ultrasen (trademark) 630 Tosoh Co., Ltd. ethylene vinyl acetate copolymer resin (vinyl acetate content 15%) (EVA)
MFR: 1.5 g / 10 min., Density: 0.936 g / cm ³ , tensile modulus: 570 kgf / cm ²
(6) Nipolon-L (trademark) FR151A manufactured by Tosoh Corporation ・ Multi-site catalytic ethylene-α-olefin copolymer resin (M-LLDPE)
MFR: 0.9 g / 10 min., Density: 0.924 g / cm ³ , tensile modulus: 2800 kgf / cm ²
(7) UBE polyethylene R500 Ube Industries, Ltd., high pressure low density polyethylene (LDPE)
・ MFR 0.5g / 10min., Density 0.922g / cm ³
[0050]
In addition, each characteristic of the said thermoplastic resin was measured on condition of the following.
1) MFR: measured in accordance with JIS K 7210 at 190 ° C. and 2.16 kgf.
2) Density: Measured according to JIS K 7112.
[0051]
Examples 1-5, Comparative Examples 1-5
A multilayer film having a thickness of 0.1 mm was molded at a molding temperature of 190 ° C. and a blow ratio of 2.5 using a three-type three-layer inflation extruder having three 50 mmφ extruders.
The compounding example and evaluation result of each multilayer film are shown to Tables 1-2.
[0052]
In addition, as for the composition example of each multilayer film, except the content of Tables 1-2, hindered amine-type weathering agent 0.5 weight%, ultraviolet absorber 0.05 weight%, a phenolic stabilizer for the composition which comprises the outer layer C 0.1% by weight, 0.1% by weight of a phosphorus stabilizer, 0.05% by weight of an antiblocking agent, 0.5% by weight of a hindered amine weathering agent for the composition constituting the intermediate layer B, 0% of an ultraviolet absorber 0.05% by weight, 0.2% by weight of a fluorosurfactant, 0.1% by weight of a phenol-based stabilizer, 0.1% by weight of a phosphorus-based stabilizer, and a hindered amine-based composition for the composition constituting the inner layer A Weathering agent 0.5 wt%, UV absorber 0.05 wt%, fluorosurfactant 0.2 wt%, phenol stabilizer 0.1 wt%, phosphorus stabilizer 0.1 wt%, anti-blocking Agent 0.05% was added.
[0053]
[Table 1]
[0054]
[Table 2]
[0055]
【The invention's effect】
The agricultural multilayer film of the present invention is excellent in flexibility, in addition to excellent tensile strength and impact strength, and using an ethylene-vinyl acetate copolymer for the layer that becomes the inner surface when stretched to a house or tunnel, Furthermore, by using a specific inorganic filler and a specific antifogging agent, it has excellent antifogging properties at low temperatures and lasts for a long period of time, so there are no drops of water that can cause pests, and There is little adhesion of water drops that reduce the amount of permeation.
In addition, by using a specific inorganic filler and a specific antifogging agent, the expression of antifogging properties at low temperatures and the antifogging sustainability were further improved. It can be used suitably.

Claims (3)

An agricultural multilayer film composed of at least an inner layer A, an intermediate layer B and an outer layer C, wherein the inner layer A is composed mainly of an ethylene-vinyl acetate copolymer having a vinyl acetate content of 2 to 10% by weight. The intermediate layer B is composed of an ethylene-α-olefin copolymer (b) having a density (d _b ) of 0.87 to 0.92 g / cm ³ and polymerized using a single site catalyst. An ethylene layer having a density (d _c ) of 0.89 to 0.95 g / cm ³ , wherein the outer layer C is polymerized using a single-site catalyst. consists α- olefin copolymer (c) from a composition mainly composed, and, d b _{<d c} der is, with respect to the inner layer a, the composition constituting the intermediate layer B and the outer layer C, BET specific inorganic surface area of 5~50m ² / g Fi Are added in amounts of 0.05 to 5% by weight, 1 to 10% by weight and 1 to 10% by weight, respectively, and the amount of the inorganic filler added to the composition constituting the outer layer C is added to the composition constituting the inner layer A. Agricultural multilayer film with more than the amount added . Antifogging agents used in the composition constituting the intermediate layer B is, claim 1 is one or more selected from the group of neutral salt with the compounds and their organic acid represented by the following formula 1 Agricultural multilayer film as described.
The agricultural multilayer film according to claim 1 or ² , wherein the multilayer film has a tensile elastic modulus of 1000 to 2000 kgf / cm ² .