JPH1177939A - Agricultural polyurethane resin film - Google Patents

Abstract

(57) [Problem] To provide an agricultural polyurethane resin film excellent in weather resistance and anti-fogging property. SOLUTION: An agricultural polyurethane resin film in which a coating derived from a composition containing a hydrophobic acrylic resin and silica sol and / or alumina sol is formed on one or both surfaces of a polyurethane resin film, wherein the polyurethane resin is And a thermoplastic polyurethane resin comprising a saturated aliphatic diisocyanate or an alicyclic diisocyanate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an agricultural polyurethane resin film. More specifically,
The present invention relates to an agricultural polyurethane resin film excellent in weather resistance and antifogging property.

[0002]

2. Description of the Related Art In recent years, in order to increase marketability and productivity of agricultural crops by semi-forcing or restraining cultivation, in recent years, agricultural vinyl chloride films, polyethylene, ethylene-vinyl acetate copolymers, and polyolefin resins have been used. BACKGROUND ART So-called house cultivation and tunnel cultivation, in which useful plants are cultivated under a covering with an agricultural covering material such as a special film as a main component, are actively performed. These agricultural films desirably have weather resistance and anti-fog properties depending on the purpose of use. Further, recently, various films mainly composed of polyester resin, fluorine resin, polyurethane resin and the like have been developed as films that can withstand long-term expansion.

[0003]

However, a film made of a polyurethane-based resin is not practically usable because of its extremely poor weather resistance. Accordingly, an object of the present invention is to provide an agricultural polyurethane resin film having excellent weather resistance and further excellent antifogging properties.

[0004]

That is, the gist of the present invention is that a film derived from a composition containing a hydrophobic acrylic resin and silica sol and / or alumina sol is formed on one or both surfaces of a polyurethane resin film. In the agricultural polyurethane resin film formed, the polyurethane resin is a thermoplastic polyurethane resin comprising a saturated aliphatic diisocyanate or an alicyclic diisocyanate.

[0005]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below in detail.
The polyurethane-based resin used in the present invention is a thermoplastic polyurethane-based resin having a thermoplastic property among polymers containing a urethane group in a molecular structure and containing a saturated aliphatic or alicyclic diisocyanate as a main raw material. As the saturated aliphatic diisocyanate, ethylene diisocyanate,
1,4-tetramethylene diisocyanate, 1,6-hexamethylene diisocyanate, 1,12-dodecane diisocyanate, 2,2,4-trimethylhexamethylene diisocyanate, 1,8-diisocyanate-4-
Examples include isocyanatooctane and the like and isomers thereof. Examples of the alicyclic diisocyanate include 4,4-dicyclohexylmethane diisocyanate, 1,3-cyclobutane diisocyanate, 1,3- and 1,4-cyclohexane diisocyanate, 1,3-cycloxylylene diisocyanate, 3-isocyanatomethyl-3, 5,
Examples thereof include 5-trimethylhexamethylene diisocyanate and isomers thereof.

[0006] These diisocyanates may be used alone or in combination of two or more. Of these, alicyclic diisocyanates are preferred, and 4,4-dicyclohexylmethane diisocyanate is particularly preferred.
The polyurethane resin is obtained by reacting these diisocyanates with a polyol and, if necessary, a chain extender by a known method.

As the polyol, a molecular weight of 500 to 40 is used.
Any polyol having a terminal active hydrogen of 00 may be used. For example, polyether polyol, polyester polyol, acrylic polyol, phenolic resin polyol, epoxy polyol, butadiene polyol, polyester-polyether polyol, acryl, styrene, vinyl addition and / or dispersion polymer polyol, urea dispersion polyol, carbonate polyol and the like can be mentioned. .

Among them, polyether polyols and polyester polyols are preferred. Specifically, polyoxytetramethylene glycol, polypropylene glycol, polyethylene glycol, poly (ethylene adipate), poly (1,4-butylene adipate), poly (1 , 6-hexane adipate), poly-ε-caprolactone and the like.

As the chain extender, a low molecular weight diol may be used. For example, aliphatic glycols, aromatic glycols and the like, specifically, ethylene glycol,
1,4-butanediol, bis (hydroxyethyl) hydroquinone and the like can be mentioned. It is produced from these raw materials using a known catalyst, for example, an amine catalyst. Examples of the amine catalyst include triethylamine, N-methylmorpholine, N-ethylmorpholine, N, N, N ', N'
-Tetramethyleneethylenediamine, pentamethyldiethylenetriamine, 1,4-diazabicyclo [2.2.
2] octane, N-methyl-N'-dimethylaminoethylpiperazine, N, N-dimethylbenzylamine,
Tertiary amines such as N-dimethylcyclohexylamine, 2-methyl-imidazole, monocyclic and bicyclic amidines, and bis- (dialkylamino) alkyl ethers. Other organometallic compounds, especially organotin compounds, can also be used as catalysts.

[0010] The polyurethane resin may be produced by a generally known polymerization method, such as any one of a one-shot method (one-step method) and a prepolymer method (two-step method). May be. The agricultural polyolefin resin of the present invention may contain, if necessary, various resin additives, such as an ultraviolet absorber, a surfactant, a flame retardant, a filler, a hydrolysis inhibitor, an antioxidant, a light stabilizer, and a charge. Inhibitors, fungicides and the like can be added in a range that does not deteriorate the performance of the film, usually in a range of 30 parts by weight or less per 100 parts by weight of the polyurethane resin.

These additives may be added to the polyurethane resin composition or the polyurethane resin, or may be added during pelletization of the resin to form a master batch. These may be weighed in a required amount, and may be mixed using a ribbon blender, a Banbury mixer, a super mixer, or other conventionally known compounding machines and mixers.

In order to form a film from the above-described polyurethane resin, a method known per se, for example, a melt extrusion method (T-die method, inflation method, etc.),
It can be performed by a casting method of a polyurethane solution or the like. The thickness of the film is 0.01-0.3 mm,
Particularly, those having a range of 0.03 to 0.2 mm are preferable. If the thickness is less than 0.01 mm, the strength of the product will not be sufficient, and if it exceeds 0.3 mm, the film will be hard and difficult to handle, which is not preferable.

The surface of the agricultural polyurethane resin film according to the present invention can be in the form of transparent, semi-matte, or matt depending on the purpose of use. The polyurethane-based resin film according to the present invention preferably has ultraviolet absorption performance. As a method of imparting the ultraviolet absorbing performance, a UV absorbing agent is blended into the resin composition before the film is formed, and then the film is formed. Alternatively, after the film is formed, the UV absorbing agent is applied to the film surface. There is a way to do that. In the case of performing the coating treatment on the surface of the latter substrate film, an ultraviolet absorber may be blended in the coating film component and applied. These methods can be used alone or in combination.

The following are examples of the ultraviolet absorbent used in the present invention. 2-ethylhexyl-2-cyano-3,3'-diphenyl acrylate and ethyl-2-cyano-3,3'-diphenyl acrylate which are cyanoacrylate-based ultraviolet absorbers. 2-hydroxy-4-methoxybenzophenone, 2,4-dihydroxybenzophenone, 2-hydroxy-4-n-octoxybenzophenone, 2-hydroxy-4-methoxy-2'-carboxybenzophenone, which is a benzophenone ultraviolet absorber , 2'-dihydroxy-4,4'-
Dimethoxybenzophenone, 2-hydroxy-4-benzoyloxybenzophenone, 2,2'-dihydroxy-4-methoxybenzophenone, 2-hydroxy-4-
Methoxy-5-sulfonebenzophenone, 2,2 ',
4,4'-tetrahydroxybenzophenone, 2,2 '
-Dihydroxy-4,4'-dimethoxybenzophenone, 2-hydroxy-5-chlorobenzophenone, bis- (2-methoxy-4-hydroxy-5-benzoylphenyl) methane.

2- (2'-hydroxyphenyl) benzotriazole, 2- (2'-hydroxy-5'-methylphenyl), which is a benzotriazole ultraviolet absorber
Benzotriazole, 2- (2'-hydroxy-5-methylphenyl) -5-carboxylic acid butyl ester benzotriazole, 2- (2'-hydroxy-5'-methylphenyl) -5,6-dichlorobenzotriazole, 2
-(2'-hydroxy-5'-methylphenyl) -5
Ethyl sulfone benzotriazole, 2- (2'-hydroxy-5'-t-butylphenyl) -5-chlorobenzotriazole, 2- (2'-hydroxy-5'-t-
Butylphenyl) benzotriazole, 2- (2'-hydroxy-5'-aminophenyl) benzotriazole, 2- (2'-hydroxy-3 ', 5'-dimethylphenyl) benzotriazole, 2- (2'-hydroxy -3 ', 5'-dimethylphenyl) -5-methoxybenzotriazole, 2- (2'-methyl-4'-hydroxyphenyl) benzotriazole, 2- (2'-stearyloxy-3', 5'-dimethyl Phenyl) -5-methylbenzotriazole, 2- (2'-hydroxy-5
-Phenyl carboxylate) benzotriazole ethyl ester, 2- (2'-hydroxy-3'-methyl-5'-
t-butylphenyl) benzotriazole, 2- (2 '
-Hydroxy-3 ', 5'-di-t-butylphenyl)
-5-chlorobenzotriazole, 2- (2'-hydroxy-3'-t-butyl-5'-methylphenyl) -5
-Chlorobenzotriazole, 2- (2'-hydroxy-5'-methoxyphenyl) benzotriazole, 2-
(2'-hydroxy-3 ', 5'-di-t-butylphenyl) -5-chlorobenzotriazole, 2- (2'-
Hydroxy-5'-cyclohexylphenyl) benzotriazole, 2- (2'-hydroxy-4 ', 5'-dimethylphenyl) -5-carboxylic acid benzotriazole butyl ester, 2- (2'-hydroxy-3', 5 ′
-Dichlorophenyl) benzotriazole, 2- (2 '
-Hydroxy-4 ', 5'-dichlorophenyl) benzotriazole, 2- (2'-hydroxy-3', 5'-
Dimethylphenyl) -5-ethylsulfonebenzotriazole, 2- (2'-hydroxy-4'-octoxyphenyl) benzotriazole, 2- (2'-hydroxy-5'-methoxyphenyl) -5-methylbenzotriazole, 2- (2'-hydroxy-5'-methylphenyl) -5-carboxylic acid ester benzotriazole, 2
-(2'-acetoxy-5'-methylphenyl) benzotriazole.

Among them, it is desirable to use a benzophenone ultraviolet absorber or a benzotriazole ultraviolet absorber. These UV absorbers can be used alone or in combination of two or more. The amount of the UV absorber used may be appropriately selected according to the thickness of the film. The amount is preferably 0.01 to 5 parts by weight, particularly preferably 0.05 to 2 parts by weight, per 100 parts by weight of the resin.
It is preferably in the range of 01 to 5 g / m ² .

The agricultural polyolefin resin film according to the present invention has a film derived from a composition containing silica sol and / or alumina sol and a hydrophobic acrylic resin formed on one or both surfaces thereof. Silica sol and / or
Alternatively, the alumina sol has a function of imparting hydrophilicity to the surface of the molded product by being formed on the surface of the polyurethane resin film.

The silica sol and / or the alumina sol preferably have an average particle size of 5 to 100 μm. If the average particle size exceeds 100 μm, the coating film becomes white and easily devitrified, and if it is less than 5 μm, the stability of the composition is lacking, which is not preferable. These may be used alone or in combination. When used alone or in combination of two or more, two or more kinds having different average particle diameters may be used in combination. In this case, silica sol / alumina sol is 95 to 5/5 to 95 (in weight ratio). (Total 100).

The silica sol and / or alumina sol may be any of a commercially available product itself dispersed in water or a commercially available silica powder or alumina powder dispersed in water to form an aqueous sol. Is also good. Alumina sol exhibits a so-called thixotropic property in which the viscosity of the dispersion rapidly increases when water is to be dispersed in water at a high concentration, and it is difficult to obtain a homogeneous dispersion, but when a medium shearing internal stirrer such as a colloid mill is used. , A homogeneous dispersion can be obtained. Further, when silica sol is mixed with this dispersion, the viscosity of the dispersion can be reduced.

In many cases, the silica sol has a negatively charged particle surface, but when used in combination with alumina sol, it is not preferable to use a negatively charged silica sol. This is because when the silica sol and the alumina sol are mixed, the mixed dispersion rapidly agglomerates, gels, and causes poor dispersion. Therefore, it is preferable that the colloidal silica has a positively charged particle surface.

The hydrophobic acrylic resin contains at least 70% by weight of an alkyl (meth) acrylate or a mixture of an alkyl (meth) acrylate and an alkenylbenzene, and α, β copolymerizable therewith. −
Homopolymers or copolymers obtained by polymerizing 0 to 40% by weight of an ethylenically unsaturated monomer are preferred.

The alkyl (meth) acrylates are alkyl esters of acrylic acid or methacrylic acid, and specifically include, for example, methyl acrylate, ethyl acrylate, and n-propyl acrylate. , Isopropyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, decyl acrylate, methyl methacrylate, ethyl methacrylate,
Examples thereof include methacrylic acid-n-propyl ester, methacrylic acid isopropyl ester, methacrylic acid-n-butyl ester, methacrylic acid-2-ethylhexyl ester and methacrylic acid decyl ester, and generally have 1 to 20 carbon atoms in the alkyl group. Acrylates and / or alkyl methacrylates having 1 to 20 carbon atoms in the alkyl group are used.

Examples of the alkenylbenzenes include styrene, α-methylstyrene, vinyltoluene and the like. The alkyl (meth) acrylates,
Or α, β-ethylenically unsaturated monomers copolymerizable with a mixture thereof with alkenylbenzenes include, for example, acrylic acid, methacrylic acid, maleic acid, maleic anhydride, fumaric acid, crotonic acid, itaconic acid Α, β-ethylenically unsaturated carboxylic acids such as ethylene sulfonic acid; 2-acrylamido-2-methylpropanoic acid; α, β-ethylenically unsaturated phosphonic acids Hydroxyl group-containing vinyl monomers such as hydroxyethyl of acrylic acid or methacrylic acid; acrylonitriles; acrylamides: glycidyl esters of acrylic acid or methacrylic acid; unsaturated monomers containing hydrolyzable silyl groups. These monomers may be used alone or in combination of two or more.

Among them, it is particularly preferable to use a hydrolyzable silyl group-containing unsaturated monomer. The unsaturated monomer containing a hydrolyzable silyl group has a chemical structure of R′SiX ₃ . R ′ is an organic residue having an unsaturated bond that can react with an organic substance such as a resin, and specific examples thereof include a vinyl group, an epoxy group, a glycidoxy group, a methacryl group, an amino group, and a mercapto group. Can be X is a hydrolyzable group capable of reacting with an inorganic substance, and specific examples include chlorine, an alkoxy group (a methoxy group, an ethoxy group, and the like).

A hydrolyzable silyl group-containing unsaturated monomer;
For example, CH_Two= CHSi (OC_TwoH_Five)_Three,
CH_Two= CHSi (OCH_Three)_Three, CH_Two= C (C
H_Three) COOC_ThreeH₆Si (OCH_Three)_Three, CH_Two= C
(CH_Three) COOC_ThreeH₆Si (OC_TwoH_FourOCH_Three)
_Three, CH_Two= CHCOOC_ThreeH₆Si (OC_TwoH_FourOC
H _Three)_Three, CH_Two= C (CH_Three) COOC_ThreeH₆Si
(OCH_Three)_TwoCH_ThreeSuch as silicate compounds; NH_TwoC
_ThreeH₆Si (OC_TwoH_Five)_Three, NH_TwoCONHC_ThreeH ₆
Si (OC_TwoH_Five)_Three, NH_TwoC_TwoH_FourNHC_ThreeH₆S
i (OCH_Three)_ThreeSilicate compounds with amino groups such as
Object; HSC_ThreeH₆Si (OC_TwoH_Five)_ThreeEtc. Mercapto
Silicate compound having a group;

[0026]

Embedded image

And silicate compounds having a glycidyl group. Even if these monomers are used alone,
Alternatively, two or more kinds may be used in combination. As a method of polymerizing a hydrophobic acrylic resin from these monomers, a method of emulsion polymerization in an aqueous medium in the presence of various emulsifiers, a method of polymerizing using a reactive emulsifier, and an oligomer containing no emulsifier are used. It can be obtained by a method of polymerizing based on soap theory and the like. The obtained acrylic resin may be used alone or in combination of two or more. The hydrophobic acrylic resin is usually used as an aqueous emulsion.In that case, even if an aqueous emulsion obtained by polymerizing each monomer in an aqueous medium is used as it is, a liquid dispersion medium is further added to this to dilute it. Alternatively, a polymer produced by the above-described polymerization may be separately collected and redispersed in a liquid dispersion medium to form an aqueous emulsion.

The hydrophobic acrylic resin in the present invention comprises:
Those having a glass transition temperature (Tg) in the range of 35 to 80 ° C are preferred. Such Tg can be obtained by selecting the type of the monomer to be used and the amount to be used (blended amount). The compounding amount of the silica sol and / or the alumina sol is preferably in the range of 0.5 to 40 times the hydrophobic acrylic resin in terms of solids weight ratio. When it exceeds 40 times, not only does the anti-fogging effect not increase in proportion to the compounding amount, but also the phenomenon that the film formed after application becomes cloudy and reduces the light transmittance appears, and the film becomes rough and brittle. It tends to be easier. On the other hand, when it is less than 0.5 times, it becomes difficult to exhibit a sufficient anti-fogging effect.

In the antifogging agent composition, a crosslinkable compound for crosslinking the binder components may be used in combination. By doing so, the water resistance of the anti-fog coating can be improved.
The amount of the crosslinking compound used is in the range of 0.1 to 30% by weight, particularly 0.5 to 10% by weight, based on the solid content of the binder component.
Is preferable. Furthermore, an antifoaming agent, a lubricant, an antistatic agent, and other various additives can be added to the coating composition, if necessary.

The coating composition of the present invention is usually used in a liquid state. The liquid dispersion medium includes an affinity or water-miscible solvent containing water. Water: monohydric alcohols such as methyl alcohol, ethyl alcohol, and isopropyl alcohol:
Polyhydric alcohols such as ethylene glycol, diethylene glycol, and glycerin; cyclic alcohols such as benzyl alcohol; cellosolve acetates: ketones;

These may be used alone or in combination. However, in consideration of the dispersion stability of the coating composition used in the present invention, the wettability after being applied to the film surface, the difficulty of removing the liquid dispersion medium, and the economic efficiency. It is preferable to decide. In addition, the film formed on the surface of the base film has a solid content adhesion amount,
Generally 0.01 to 10 g / m ² , especially 0.1 to 5 g / m ²
It is preferably in the range of ² .

In order to form a coating on the surface of the substrate film, a solution or dispersion of each composition is generally coated with a doctor blade coating method, a roll coating method, a dip coating method, a spray coating method, a rod coating method, a bar coating method, A coating method known per se, such as a knife coating method or a brush coating method, may be employed, followed by drying after application. As a drying method after the application, any of natural drying and forced drying may be adopted. When the forced drying method is employed, the drying may be performed usually at a temperature of 50 to 250 ° C, preferably 70 to 200 ° C. Heat drying includes a hot air drying method, an infrared drying method, a far-infrared drying method, and the like. An appropriate method may be employed, and in consideration of the drying speed and stability, it is advantageous to employ the hot air drying method.

If the adhesiveness between the base film and the coating is not sufficient, the surface of the base film may be washed with alcohol or water, subjected to a plasma discharge treatment or a corona discharge treatment, or primed with another paint or primer. It may be pre-processed. The coating on one or both sides of the base film may be formed on one side or both sides of the base film for the purpose of improving the workability at the time of house expansion of the film. When the film according to the present invention is actually used for agriculture, when the coating is formed only on one side, the surface provided with the coating is used so as to be inside a house or a tunnel.

[0034]

EFFECT OF THE INVENTION The agricultural polyurethane resin film according to the present invention, by adopting the constitution of the present invention, becomes an agricultural polyurethane resin film having dramatically improved weather resistance and anti-fog properties. The value of application as agricultural covering materials such as films and lining films is extremely high.

[0035]

The present invention will be described below in detail with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist of the invention. Examples 1 to 7, Comparative Examples 1 and 2 (1) Synthesis of Base Resin Polyol component 1000 of the type shown in Tables 1 and 2
g and 500 g of the chain extender were stirred at a high speed with a supermixer, and 300 g of the diisocyanate component was stirred and reacted at 60 ° C. The mixture was extruded with a 30 mmφ twin-screw extruder (Pla Giken Co., Ltd.) to form pellets. Table-1 to Table-2
And the ultraviolet absorber were mixed to obtain a polyurethane resin master batch.

(2) Preparation of Substrate Film The master batch obtained in (1) was used as a T-die extruder with a single-layer die of 400 mmφ (manufactured by Pura Koken Co., Ltd.) and an extruder of 40 mmφ (( (Pla Giken Co., Ltd.)
Using an extruder at a cylinder temperature of 170 ° C., a die temperature of 180 ° C., and a screw rotation speed of 30 rpm.
To obtain a film having a thickness of 0.15 mm as shown in Table 2.

[0037]

[Table 1]

[0038]

[Table 2]

(3) Formation of Coating Layer a) Preparation of Hydrophobic Acrylic Component 150 parts of isopropyl alcohol was placed in a 1-liter flask equipped with a stirrer and a cooler, and the temperature was raised to 80 ° C. under a nitrogen stream. Then, 300 parts of a mixture of each monomer shown in Table 3 is dissolved in 50 parts of isopropyl alcohol and added dropwise over 3 hours. 30 minutes, 60 minutes, 18
After dropping three times at 0 minutes, the mixture was reacted at 80 ° C. for 2 hours to obtain each resin solution. To 100 parts of this resin solution, 6 parts of acid was added and diluted with water to obtain a slightly yellowish polymer solution having a nonvolatile content of 30%.

[0040]

[Table 3]

B) Preparation of coating composition The product obtained in a) (hydrophobic acrylic component, resin b)
D) Silica sol and / or alumina sol of the type and amount shown in Table 4 and a crosslinking agent and a liquid dispersant were blended to obtain various coating agent compositions.

[0042]

[Table 4]

On one side of the base film prepared in (2),
Each of the above coating compositions was applied using a # 5 bar coater. The liquid dispersion medium which held the applied film in an oven at 80 ° C. for 1 minute was volatilized. The amount of coating of the obtained film was about 1 g / m ² .

(4) Evaluation of Film Each of the obtained films was evaluated by the following method. The results are shown in Table-5. A) Transparency test The parallel light transmittance of the obtained film at a wavelength of 555 mm was measured using a spectrophotometer (type 330, manufactured by Hitachi, Ltd.).
And its value was indicated. B) Anti-fog test In a field in Isshi-gun, Mie Prefecture, a 5.4m-wide, 3m-high, 15m-depth pipe house was obtained by using one kind of film obtained at a time so that the molded surface of the film was inside the house. Coated. As for the evaluation method, the state of water droplets adhering to the inner surface of the film being stretched was visually observed over time. The evaluation criteria are as follows (test started in December 1992).

A: Water droplets adhering to the film surface (the side facing the inside of the house, the same applies hereinafter) are united and spread in a thin film form, and the area of this thin film portion is 2/3 of the film surface.
What extends over. : Coalescence of water droplets adhering to the film surface is observed, but the area of this thin film portion is 2/3 of the film surface
Less than, 1/2 or more. ×: coalescence of water droplets adhering to the film surface is observed, but the area of this thin film portion is １ ／ of the film surface
Less than one. Δ: Coalescence of water droplets adhering to the film surface is recognized, but the shape of the thin film portion is not recognized. ×: No coalescence of water droplets adhering to the film surface is observed.

C) Accelerated antifogging test 300 cc of water (50 ° C.) was placed in a 500 cc beaker, and the beaker was coated with a sample film so that the surface on which the coating was formed was located inside the beaker. (50 ° C.), the beaker was tilted at 10 ° from the ground surface to be immersed in water from the lower part to ３, and left in a constant temperature room at 25 ° C. for a predetermined time to visually observe the state of the film surface.
The state of flow of water droplets on the film surface was evaluated according to the same criteria as in the anti-fog test.

D) Adhesion test A cellophane tape was adhered to the surface on which the film was formed, and when the cellophane tape was peeled off, the state of peeling of the film was visually observed. The evaluation criteria are as follows. ：: The film did not peel off at all and remained completely. ×: A film in which 2/3 or more of the film remained without peeling. Δ: Two-thirds or more of the coating peeled off. ×: The film was completely peeled.

[0048]

[Table 5]

Claims (8)

[Claims] An agricultural polyurethane resin film comprising a polyurethane resin film and a film derived from a composition containing a hydrophobic acrylic resin and silica sol and / or alumina sol formed on one or both surfaces of the polyurethane resin film. Is a thermoplastic polyurethane-based resin comprising a saturated aliphatic diisocyanate or an alicyclic diisocyanate. 2. The agricultural polyurethane resin film according to claim 1, wherein the thermoplastic polyurethane resin mainly comprises an alicyclic diisocyanate, a bifunctional polyol and a low molecular diol. 3. The alicyclic diisocyanate is 4,4-dicyclohexylmethane diisocyanate.
Or the polyurethane resin film for agriculture according to claim 2. 4. The agricultural polyurethane resin film according to claim 2, wherein the bifunctional polyol is a polyether polyol or a polyester polyol. 5. The agricultural polyurethane resin film according to claim 1, wherein the polyurethane resin film contains an ultraviolet absorber. 6. The amount of silica sol and / or alumina sol is 0.5% by weight of the hydrophobic acrylic resin in terms of solids weight ratio.
The agricultural polyurethane resin film according to any one of claims 1 to 5, which is in a range of up to 40 times. 7. The hydrophobic acrylic resin contains at least 70% by weight or more of an alkyl (meth) acrylate or a mixture of an alkyl (meth) acrylate and an alkenylbenzene, and is copolymerizable therewith. The agricultural polyurethane according to any one of claims 1 to 6, which is a homopolymer or a copolymer obtained by polymerizing 0 to 40% by weight of an α, β-ethylenically unsaturated monomer. Resin film. 8. The α, β-ethylenically unsaturated monomer is a hydrolyzable silyl group-containing unsaturated monomer.
The agricultural polyurethane resin film according to the above.