JP3223292B2 - Agricultural house covering - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a covering material for an agricultural house. More specifically, the present invention relates to an agricultural house covering material made of a fluororesin film having excellent antifouling properties.

[0002]

2. Description of the Related Art In recent years, the spread of agricultural houses has been remarkable, and they are widely used for forcing cultivation and suppression cultivation of vegetables, fruits, flowers and the like. These agricultural houses are generally made of iron, aluminum, etc. as a framework, and the covering material is a plastic film such as a polyethylene film, an ethylene-vinyl acetate copolymer film, a polyester film, a vinyl chloride film, or an acrylic resin, a polycarbonate resin, or a rigid vinyl chloride. A plastic plate such as a resin, a plate glass, or the like is applied.

[0003] However, agricultural houses have always been pursued in terms of economy, labor saving, and the like, and there is a demand for a coating material that is more excellent in durability and workability.

[0004] In such a transition, a fluororesin film having the highest weather resistance among plastics used as a coating material has been used in spite of its disadvantage in price compared with other types of coating materials. Is being done. Moreover, the fluororesin film has the mechanical strength and
In addition to being excellent in light transmittance and the like, the application is expanding because it can be easily extended to existing tunnel houses, pipe houses, large steel frame houses, and the like.

[0005]

However, the conventional agricultural house covering material made of a fluororesin film, although the film surface is hardly stained, increases the adhesion of dirt, dust and the like over a long period of time, and the stain is rainwater or the like. And it is difficult to remove easily. For this reason, the light transmittance of the film is deteriorated, which causes not only poor growth of cultivated crops due to insufficient light transmittance, but also causes of disease, and also has a disadvantage that the spread of disease is easily promoted.

[0006] The present invention solves the above problems,
Excellent antifouling property and its sustainability as a coating material for agricultural houses,
Still another object is to provide a covering material for an agricultural house having long-term durability.

[0007]

According to the present invention, there is provided a covering material for an agricultural house according to the present invention, comprising a fluororesin film provided with an antifouling layer on one surface and a drip-proof layer on the other surface. Wherein the antifouling layer contains at least one selected from the group consisting of (a) a polymeric binder and a cationic polymer, and (b) an aqueous resin and sulfonated polystyrene and / or a salt thereof. Consists of a composition.

In the present invention, the material of the fluororesin film is not particularly limited, and various known materials can be used. Typical examples are tetrafluoroethylene polymers,
Ethylene tetrafluoroethylene copolymer, tetrafluoroethylene-6-fluoropropylene copolymer, tetrafluoroethylene-
Examples include perfluoroalkyl vinyl ether copolymers, vinylidene difluoride polymers, ethylene trifluoride polymers, ethylene monofluoride polymers, ethylene trifluoride polymers, and copolymers and mixtures thereof. Can be. However, from the viewpoints of mechanical properties, film forming properties, processability and the like, it is preferable to use a tetrafluoroethylene-6-fluoropropylene copolymer or an ethylene-4-fluoroethylene copolymer. Those containing a copolymer as a main component are particularly preferred. The main component refers to a resin component that is 50% or more, preferably 70% or more, of the resin component, and may contain other substances as appropriate. The resin to be added is not particularly limited, and examples thereof include a polyolefin-based resin. Also, if necessary, known additives in a fluororesin film in an amount that does not impair the effects of the present invention, for example, heat stabilizers, oxidation stabilizers, weather stabilizers, ultraviolet absorbers, pigments, dyes, Inorganic or organic fine particles, dispersants, coupling agents, fillers and the like may be blended.

Further, the fluororesin film can be used in any of unoriented, uniaxial or biaxial orientation, but when mechanical strength is required, an oriented film is desirable.

[0010] The thickness of the fluororesin film is not particularly limited, and an appropriate thickness can be set within a range of about 25 to 500 µm. In this application, the total light transmittance of the fluororesin film is preferably 70% or more, and more preferably 80% or more in terms of characteristics.

Further, in the present invention, when an antifouling layer or a drip-proof layer is formed on the surface of the fluororesin film, not only the coating properties are improved by performing the surface treatment, but also the adhesion of each layer,
Since water resistance and solvent resistance are improved, they can be used more preferably. As the surface treatment, a known method, for example, a corona discharge treatment (in air, in nitrogen, in carbon dioxide gas, or the like), a plasma treatment (high pressure, low pressure), or the like can be suitably used. The treatment intensity is not particularly limited and may be a desired value. As a measure of the treatment intensity, the surface wetting index of the film measured based on JIS-K-6768 is preferably 40 dyn / cm or more, more preferably. It is desirable to be 45 dyn / cm or more.

The antifouling layer of the present invention comprises at least one selected from the group consisting of (a) a polymeric binder and a cationic polymer, and (b) an aqueous resin and sulfonated polystyrene and / or a salt thereof. The composition comprises: The term "main component" means that the substance itself is 50% by weight or more in the antifouling layer, and other substances may be added as appropriate. In the present invention, such an antifouling layer is provided on one surface of the film support.

The polymer binder used in the present invention is selected from a thermoplastic resin or a curable resin, and is a resin which is soluble in a known organic solvent and has a small amount of a hydrophilic group or a hydrophilic component. It is preferable in terms of the water resistance of the antifouling layer. Specific examples include thermoplastic resins such as polyester, polyamide, polyesteramide, polyvinyl acetal, polyvinyl chloride, poly (meth) acrylate, polyimide, polyurethane, polycarbonate, polystyrene, polymethylpentene, polyolefin, and halogenated polyolefin. Alkyd resin, polyamide imide, silicon resin, fluororesin and the like, and copolymers and mixtures thereof. Examples of the curable resin that is cured by light, heat, oxygen, and the like include, for example, a phenol resin, a melamine resin, an epoxy resin, and a crosslinkable organosilicon resin. In the present invention, water resistance of the antifouling layer, solvent resistance, heat resistance,
It is preferable to use a thermosetting resin from the viewpoint of abrasion resistance, mechanical strength, and the like, and it is more preferable to use a thermosetting resin that can be crosslinked by using a well-known crosslinking agent.

In the present invention, among the above-mentioned polymer binders, urethane resins and acrylic copolymer resins are preferably used, and more preferably, acrylic copolymer resins are used.
More preferred are poly (meth) acrylate copolymers. The poly (meth) acrylate copolymer is a poly (meth) acrylate copolymer containing a reactive monomer. As such a reactive monomer, as a functional group, for example, a carboxyl group (for example,
(Meth) acrylic acid, etc.), hydroxyl group (such as 2-hydroxyethyl (meth) acrylate), amide group (such as (meth) acrylamide), glycidyl group (such as glycidyl (meth) acrylate), amino group (( (Meth) 2-ethylaminoethyl acrylate).

The acrylic copolymer resin preferably has a hydroxyl value of 40 or more, more preferably 45 or more, in terms of adhesion to a film support, coating film forming properties, and the like. The hydroxyl value in the present invention is defined as follows. That is, it is the number of mg of potassium hydroxide corresponding to the number of moles of the hydroxyl group contained in 1 g of the sample.

Examples of the organic solvent for the polymer binder include well-known organic solvents such as alcohols, carboxylate esters, ketones, aliphatic hydrocarbons, alicyclic or aromatic hydrocarbons, and mixtures thereof. It is preferable to select one that does not adversely affect the applicability and the like.

The cationic polymer referred to in the present invention is a cationic polymer such as a quaternary ammonium salt.
Among them, a cationic acrylic polymer is preferably used. Examples of the cationic acrylic polymer include butyl methacrylate and salts of dimethylaminoethyl methacrylate. Specifically, "Elecond" PQ-10, PQ-50B, B-149, etc. manufactured by Soken Chemical Co., Ltd. are effective. Can be used. Since this cationic polymer is a polymer unlike the conventional antistatic agent, it is uniformly mixed in the antifouling layer and its state does not change, so that a phenomenon such as the conventional antistatic bleed-out does not occur.
Therefore, the excellent antistatic property of the cationic polymer is exhibited without a long-term decrease.

The aqueous resin in the present invention is a water-soluble resin or a water-dispersible resin, which is selected from a thermoplastic resin, a thermosetting resin, a reactive resin, etc., having a good affinity for a base film. And those not containing a fluorine atom in the molecular structural formula are preferred. For example, natural water-soluble polymers such as glue, casein, polyethylene glycol, polyvinyl alcohol, methyl cellulose and other cellulose derivatives, synthetic water-soluble polymers such as urea resins and melamine resins, water-soluble polyesters such as polyester ethers, polyethylene terephthalate, poly Polyesters such as butylene terephthalate, polyacrylic acid esters and polymethacrylic acid esters, polyacrylonitrile, polyamide, polyvinyl butyral, polyvinyl chloride, polyvinylidene chloride, polystyrene, polyvinyl acetate, polybutadiene, polyurethane, polychloroprene, phenolic resins, and alkyd resins ,Epoxy resin,
Copolymers such as crosslinkable silicone resins, and mixtures thereof, among which polyurethane-based, polyester-based, polyacryl-based water-soluble resins or water-dispersible resins are preferable, and polyacryl-based water is particularly preferable. It is a dispersible resin.

Here, the polyacrylic resin is represented by a basic formula

Embedded image (R: hydrogen or methyl group, R ′ is an alkyl group having 1 to 18 carbon atoms), alkyl methacrylate, acrylic acid, methacrylic acid, β-
Hydroxy acrylate, β-hydroxy methacrylate, β-hydroxypropyl acrylate, β-hydroxypropyl methacrylate, polyoxyethylene glycol monomethacrylate, polyethylene polytetramethylene ether glycol monomethacrylate, dimethylaminoethyl methacrylate, diethylaminoethyl methacrylate, acrylamide, methacrylamide,
N-methyl methacrylamide, Nn-butoxymethyl acrylamide, acid phosphooxyethyl methacrylate, 3-chloro-2-acid phosphooxypropyl methacrylate, 3-chloro-2-hydroxypropyl methacrylate, glycidyl acrylate, glycidyl methacrylate, tetrahydrofur Furyl acrylate, tetrahydrofurfuryl methacrylate, methoxypolyethylene glycol monomethacrylate, 3-acrylamido-2-methylpropanesulfonic acid, N-methylolacrylamide, N-methylolmethacrylamide, polyoxyethylene glycol dimethacrylate,
1,3-butylene glycol dimethacrylate, 1,6
-One or more copolymers selected from hexanediol dimethacrylate, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, dibromoneopentyl glycol dimethacrylate, tetramethylolmethane triacrylate, and the like. An alkyl methacrylate / alkyl acrylate copolymer is preferred from the viewpoint of the transparency of the coating film, and examples thereof include a methyl methacrylate / ethyl acrylate copolymer. Further, an aqueous dispersion of an acrylate or methacrylate copolymer obtained by copolymerizing a monomer containing a carboxyl group or a methylol group, acrylamide, or the like is preferable from the viewpoint of adhesion to a substrate. Also,
It is more preferable to use an acrylic copolymer containing methyl methacrylate in an amount of 40 wt% or more and 80 wt% or less in terms of a copolymer composition because of excellent transparency.

Further, the number average molecular weight of the acrylic copolymer is not particularly limited, but is preferably 200,000 to 1,000,000,
More preferably, it is 300,000 to 800,000 in view of the durability of the coating film.

The sulfonated polystyrene and / or a salt thereof in the present invention is represented by a basic formula

Embedded image Is an anionic polymer obtained by sulfonating polystyrene or polymerizing styrene sulfonic acid. X ⁺ ions include H ⁺ , NH ₄ ⁺ , K ⁺ , Na ⁺ , and Li ⁺
And the like. Among them, it is preferable to use sulfonated polystyrene in which X ⁺ ions are H ⁺ and NH ₄ ^{+ from} the viewpoint of antistatic property, and H ⁺ ions are more preferable because the thickness of the coating film can be reduced.

The molecular weight of the sulfonated polystyrene and / or a salt thereof is preferably 10,000 to 1,000,000, more preferably 30,000 to 300,000.

In the agricultural house covering material of the present invention, water vapor radiated from soil or plants is aggregated on the inner surface of the house and adheres as fine water droplets, and these water droplets cause various adverse effects such as deterioration of light transmittance. Therefore, a drip-proof layer is necessary. For the drip-proof layer, a known one disclosed as a drip-proof agent can be applied, and usually, a hydrophilic polymer, a surfactant, colloidal silica, alumina sol, or the like or a mixture of these as a main component is used. It can be suitably used.

In addition, in an agricultural house, particularly in facility cultivation from late autumn to winter, fog is generated near the inner surface of the covering material in the morning or in the evening when the temperature difference with the outside air tends to change rapidly, Moreover, natural convection causes a phenomenon that covers the entire area of the house. However, the fog generated wets the leaves, stems, flowers, fruits, etc. of the cultivated crops, causing disease, poor growth due to insufficient light transmission, and increased fuel efficiency for drying the cultivated crops. Therefore, it is desirable that the drip-proof layer contains an anti-fog agent. As the antifog agent, known ones can be applied, and among them, an organic fluorine surfactant is preferable. Examples of the organic fluorine-based surfactant include those containing a linear or branched perfluoroalkyl group or perfluoroalkenyl group, and include an anionic surfactant, a cationic surfactant, and a zwitterionic surfactant. At least one selected from the group consisting of a surfactant, a nonionic surfactant and the like is applied.

If necessary, the drip-proof layer may further contain known additives such as an antifoaming agent, a coating improver, an antioxidant, an ultraviolet absorber, a dye and a pigment. Also,
The thickness of the drip-proof layer is not particularly limited, but is preferably 0.01 to 5.0 μm, more preferably 0.1 to 5.0 μm.
Those having a thickness in the range of from 0.05 to 1.0 μm have uniform layer formability,
It is preferable in terms of handling properties, drip-proof properties, and the like.

In the present invention, the surface electric resistance of the antifouling layer is 10
^It is desirably ¹³ Ω / □ or less, preferably 10 ¹¹ Ω / □ or less. If the surface electric resistance exceeds 10 ¹³ Ω / □, the coating material is liable to adhere to the dust due to the charging phenomenon, which is not preferable.

In the present invention, in order to further improve the adhesion, water resistance, scratch resistance, mechanical strength, heat resistance and the like of the antifouling layer, it is preferable that the antifouling layer contains a cross-linking agent. The cross-linking agent referred to in the present invention is a cross-linking reaction with a functional group present in a polymer binder or an aqueous resin, such as a hydroxyl group, a carboxyl group, a glycidyl group, or an amino group.
A cross-linking agent for finally forming an antifouling layer having a three-dimensional network structure. Typical examples are methylolated or alkylolated urea-based, melamine-based, acrylamide-based, polyamide-based resins, and epoxy compounds, isocyanates And aziridine compounds. In the present invention, among these, application of an isocyanate compound is preferred from the viewpoint of adhesion to a film support, crosslinkability, and the like. These crosslinking agents may be used alone or in some cases as 2
More than one species may be used in combination. The amount of the cross-linking agent to be added is appropriately selected depending on the type of the cross-linking agent.
The amount is preferably 0.01 to 50 parts by weight with respect to 00 parts by weight,
0.1 to 30 parts by weight is more preferable. Further, it is more preferable to use a crosslinking catalyst together with a crosslinking agent because crosslinking proceeds more. Known catalysts such as salts, inorganic substances, organic substances, acid substances and alkaline substances can be used as the crosslinking catalyst. The amount of the crosslinking catalyst to be added is preferably 0.001 to 10 parts by weight, more preferably 0.1 to 5 parts by weight, based on 100 parts by weight of the resin solid content. The coating material to which the cross-linking agent is added is cross-linked by heating, ultraviolet rays, electron beams or the like after being applied to the film support, but the heating method is generally used.

In the present invention, the thickness of the antifouling layer is not particularly limited, but is preferably 0.001 to 20 μm, more preferably 0.01 to 10 μm. It is desirable in terms of uniform formability, adhesion and the like. The antifouling layer, if necessary, known additives in an amount that does not impair the effects of the present invention, for example, a heat stabilizer, a weather stabilizer,
It may contain an ultraviolet absorber, a pigment, a dye, inorganic or organic fine particles, or the like. In particular, the addition of fine particles is more preferable because the lubricity can be improved. As the inorganic particles, for example, silica, colloidal silica, alumina, alumina sol,
Kaolin, talc, mica, calcium carbonate and the like, as the organic particles, for example, polystyrene, polymethacrylate, polymethyl methacrylate, styrene-divinylbenzene copolymer, polyvinylidene chloride, melamine resin and the like, fine particles, Average particle size 0.01 ~
2000 μm is preferred, and more preferably 0.05 to 5
The mixing ratio is preferably from 0.01 to 50 parts by weight, more preferably from 0.1 to 10 parts by weight, based on 100 parts by weight of the total resin solids.

Next, as a method of providing an antifouling layer and a drip-proof layer, a method of applying a solution adjusted to a predetermined amount in advance to a film serving as a substrate in a film forming step, followed by drying,
A method of providing a coating-drying step after winding as a single film of the base film can be preferably applied.

The application method is not particularly limited, and an extrusion lamination method, a melt coating method, etc. may be used. However, a gravure coating method, a reverse coating method, a kiss coating method, Known methods such as a die coating method and a metaling bar coating method can be applied. The concentration of the coating material and the conditions for drying the coating film are not particularly limited, but the drying conditions for the coating film are desirably performed within a range that does not adversely affect the properties of each layer and the base film.

[0031]

[Measurement method and evaluation method] The characteristic values in the present invention are based on the following measurement methods and evaluation criteria.

(1) Surface Electric Resistance Using a digital ultra-high resistance / micro ammeter (type R8340) manufactured by Advantest Co., Ltd., 20 ° C., 65% RH
Was measured.

(2) Chargeability Using a static honest meter type S-4104 (manufactured by Shishido Shokai), after charging the antifouling layer with a discharge voltage of 10 kV, the charge decay at 20 ° C. and 60% RH was reduced by half (second). The evaluation was made as follows.

：: good (less than 1 second) Δ: slightly inferior (more than 1 second and less than 30 seconds) ×: poor (more than 30 seconds)

(3) Drip-proof property A steel house of 30 tsubos (2.5 m below eaves, roof slope 15
°), and cultivated under crop cultivation for 6 months in winter (October to 3
) Was visually observed. The evaluation criteria were: ○: good Δ: slightly poor ×: bad.

(4) Antifouling property [I] Each sample was spread on the roof part of the above (3) house, and the degree of dust adhering to the outer surface of the coating material was compared and observed with time, and evaluated according to the following criteria.

：: good Δ: slightly poor ×: bad

(5) Antifouling property [II] Each sample was installed in a place where a large amount of dust was generated outdoors so as not to be exposed to rain, and the degree of dust adhering to the outer surface of the covering material was compared and observed. Was evaluated.

：: good Δ: slightly poor ×: bad

[0040]

The present invention will be described with reference to the following examples and comparative examples, but the present invention is not limited to these examples.

Example 1 A corona discharge treatment was applied to both sides of a 60 μm thick ethylene-tetrafluoroethylene copolymer resin film (manufactured by Toray Industries, Inc.)
On one surface, toluene / methyl ethyl ketone (mixing ratio: 1: 1) is used as a diluting solvent, and a hot-crosslinkable acrylic resin "COTAX" L having a hydroxyl value of 60 is used as a polymer binder.
H613 (manufactured by Toray Industries, Inc.) and cationic polymer "ELECOND" PQ-5OB (manufactured by Soken Chemical Co., Ltd.) were mixed at a solid content ratio of 1: 1 to apply a uniform coating material having a concentration of 10% by weight. The layer is dried at 120 ° C. for 1 minute and has a thickness of 0.6
A μm antifouling layer was provided.

Next, on the non-coated surface of the film, polyvinyl alcohol "Denkapovar" K-24E (manufactured by Denki Kagaku Kogyo Co., Ltd.) and colloidal silica (manufactured by Catalyst Chemical Industry Co., Ltd.), a nonionic type Surfactant "Nonion" NS
-210 (manufactured by NOF CORPORATION) with a solid content weight ratio of 8
A coating having a composition of 0: 19.7: 0.3 and having a concentration of 7% by weight uniformly dispersed was applied, and the applied layer was dried at 120 ° C. for 1 minute to form a drip-proof layer having a thickness of 0.8 μm. . The properties of the thus-obtained covering material for an agricultural house were as shown in Table 1 and were excellent in each property.

Example 2 Based on Example 1, the aqueous resin was methyl methacrylate / ethyl acrylate (50/50) mol% as an antifouling layer.
An acrylic polymer having an average molecular weight of 500,000, into which 2.5 parts by weight of a carboxyl group and a methylol group are introduced as functional groups, sulfonated polystyrene and / or a salt thereof is
A uniform coating material having a concentration of 10% by weight was mixed with a compound having a molecular weight of about 70,000 having NH ₄ ⁺ as the X ⁺ ion of the ₂ ⁻ X ⁺ group and using a solid content weight ratio of 80:20. A coating material for an agricultural house was produced in the same manner as in Example 1. As shown in Table 1, the characteristics of the coating material for an agricultural house were all excellent.

Example 3 Based on Example 1, the fluororesin film of Example 1 was a 60 μm-thick ethylene hexafluoride-propylene hexafluoride copolymer resin film (manufactured by Toray Industries, Inc.), and both sides were constantly formed. A coating material for an agricultural house was produced in the same manner as in Example 1 except that the material subjected to the pressure plasma treatment was used. As shown in Table 1, the characteristics of the coating material for an agricultural house were excellent.

Comparative Example 1 A coating material for an agricultural house was prepared in Example 1 without providing an antifouling layer and a drip-proof layer. As shown in Table 1, the properties as a coating material for an agricultural house are inferior in antifouling property and drip-proof property and lack suitability.

[0046]

[Table 1]

[0047]

In the covering material for an agricultural house of the present invention, an antifouling layer made of a specific resin composition is formed on one surface of the fluororesin film, and a drip-proof layer is formed on the other surface. The following excellent effects could be obtained by utilizing the characteristics of

First, the coating material for an agricultural house of the present invention has both excellent antifouling properties and drip-proof properties, and can maintain the excellent antifouling effect as it is. Do not disturb.

Further, since the covering material for an agricultural house of the present invention has an antistatic property, it is excellent in handleability at the time of house expansion and the like.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-54-81387 (JP, A) JP-A-57-83451 (JP, A) JP-A-52-155191 (JP, A) JP-A 61-83191 204240 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B32B 1/00-35/00

Claims (4)

(57) [Claims] 1. A coating material for an agricultural house comprising a fluororesin film provided with an antifouling layer on one surface and a drip-proof layer on the other surface, wherein the antifouling layer comprises (a) a polymer binder And a cationic polymer, (b) a composition mainly composed of at least one selected from an aqueous resin and sulfonated polystyrene and / or a salt thereof. 2. The covering material for an agricultural house according to claim 1, wherein the antifouling layer has a surface electric resistance of 10 ¹³ Ω / □ or less. 3. The covering material for an agricultural house according to claim 1, wherein the drip-proof layer contains an anti-fog agent. 4. The covering material for an agricultural house according to claim 1, wherein the fluororesin film is made of a composition containing an ethylene-tetrafluoroethylene copolymer resin as a main component. .