JPH0624812B2 - Agricultural soft vinyl chloride resin film - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION "Industrial field of application" The present invention is an agricultural product which is not affected by storage conditions in a film wound state and is excellent in anti-fog property after spreading, and this excellent property lasts for a long time. The present invention relates to a soft vinyl chloride resin film for use.

“Prior Art” Recently, farmers cultivating useful plants have widely adopted a method of accelerating or suppressing cultivation of useful plants in a house (greenhouse) or a tunnel for the purpose of improving profitability.

Polyethylene film, ethylene-vinyl acetate copolymer film, polyester film, polycarbonate film, vinyl chloride resin film, glass, etc. are used as the covering material for this agricultural house or tunnel. Among them, vinyl chloride resin film, especially soft vinyl chloride resin film containing a large amount of plasticizer,
Compared with other synthetic resin films, glass, etc., it is widely used because it has the best overall light transmittance, heat retention, mechanical strength, durability, workability, economy and the like.

However, when a soft vinyl chloride resin film is used to cover a house or a tunnel, the sun's rays are poorly transmitted due to cloudiness on the inner surface of the house, which slows down the growth of plants or causes water drops to fall on cultivated plants. By
The young shoots may be harmed or cause disease.

In order to eliminate such inconvenience, it is known that the surface of the soft vinyl chloride resin film may be provided with antifogging property. To impart anti-fogging property to the surface of the soft vinyl chloride resin film, a method of kneading a hydrophilic substance such as a surfactant into the soft vinyl chloride resin to form a film, or after forming the film, A method of applying a hydrophilic substance or a water-soluble polymer substance on the surface is adopted.

Although various methods have been proposed as the latter coating method,
Among them, the antifog composition obtained by mixing colloidal silica and / or alumina sol with a suitable hydrophilic binder has excellent coatability, and was applied to a film and dried to form it on the film surface. The coating exhibits excellent anti-fogging property and anti-fogging durability.

However, such a coating film containing an inorganic aqueous sol as a main component has a problem that the surface is easily contaminated with various substances because the adsorption activity is high reflecting the characteristics of the inorganic sol. Since the product form is provided in a rolled state, the soft vinyl chloride resin film for agriculture has an antifogging performance depending on the use conditions as a result of the formed film being influenced by the compounding agent in the base material through the contact surface. There is a problem of decrease.

[Problems to be Solved by the Invention] The present inventors have an object to provide a vinyl chloride resin film for agricultural use which, in such a situation, exhibits excellent antifogging properties for a long period of time regardless of the product form. As a result of intensive studies, the present invention has been completed.

"Means for Solving the Problems" However, the gist of the present invention is that a film derived from a fluororesin coating composition is formed on one surface of a soft vinyl chloride resin film, and the other surface of the film is formed. And a colloidal silica and / or alumina sol and a film derived from an antifogging agent composition containing a binder as a main component are formed in the soft vinyl chloride resin film for agriculture.

Hereinafter, the present invention will be described in detail.

(1) In the present invention, the vinyl chloride resin is a copolymer whose main component is polyvinyl chloride in addition to polyvinyl chloride. Examples of the monomer compound copolymerizable with vinyl chloride include vinylidene chloride, ethylene, propylene, acrylonitrile, maleic acid, itaconic acid, acrylic acid, methacrylic acid, vinyl acetate and the like. These vinyl chloride resins may be produced by any of conventionally known production methods such as emulsion polymerization method, suspension polymerization method, solution polymerization method and bulk polymer.

Agricultural soft vinyl chloride resin film according to the present invention,
In order to impart excellent flexibility and mechanical strength, the plasticizer is usually added in an amount of about 20 to 60 parts by weight with respect to 100 parts by weight of the base resin.

(2) Examples of the plasticizer include phthalic acid derivatives such as di-n-octyl phthalate, di-2-ethylhexyl phthalate, dibenzyl phthalate, diisodecyl phthalate, didodecyl phthalate and diundecyl phthalate; and diisooctyl phthalate. Isophthalic acid derivative; adipic acid derivative such as di-n-butyl adipate, dioctyl adipate; maleic acid derivative such as di-n-butyl maleate; citric acid derivative such as tri-n-butyl citrate; itacone such as monobutyl itaconate Acid derivatives; oleic acid derivatives such as butyl oleate; ricinoleic acid derivatives such as glycerin monoricinoleate; tricresyl phosphate, epoxidized soybean oil, and epoxy resin plasticizers.

(3) Further, in order to impart flexibility to the resin film,
The material is not limited to the above-mentioned plasticizer, and for example, thermoplastic polyurethane resin, polyvinyl acetate, etc. can be used.

(4) The agricultural soft vinyl chloride resin film of the present invention preferably contains an ultraviolet absorber or a light stabilizer. As a UV absorber, benzophenone-based,
Various substances such as benzotriazole can be used. The light stabilizer is represented by the following general formula [I]. A hindered amine compound containing one or more structural units in one molecule is suitable.

General formula [In the formula [I], R _{1 to} R ₄ represent an alkyl group having 1 to ₄ carbon atoms, and R ₅ represents hydrogen or an alkyl group having 1 to 4 carbon atoms. A typical example is a hindered amine compound represented by the general formula [II].

General formula (In the formula, R represents phosphorus or a mono-to-tetraacyl group derived from a mono- to tetra-valent carboxylic acid, and n represents an integer of 1 to 4, respectively.) Specific examples of the general formula [II] include Specifically, for example, as shown in Japanese Patent Publication No. 63-51458, 4
-Cyclohexinoyloxy-2,6,6-tetramethylpiperidine, 4-benzoyloxy-2,2,6,6
Examples of known stabilizers for polyvinyl chloride include -tetramethylpiperidine, 4- (o-chlorobenzoyloxy) -2,2,6,6-tetramethylpiperidine and the like.

If the amount of the hindered amine-based compound added to the vinyl chloride-based resin film is too small, the weather resistance of the film will not be sufficiently excellent, which is not preferable, and even if the amount is too large, the weather resistance of the film is proportional to the amount added. However, there is a problem of spouting from the film surface.
The preferable blending amount is in the range of 0.2 to 1.0 part by weight with respect to 100 parts by weight of the vinyl chloride resin.

Therefore, the mixing ratio of the ultraviolet absorber (A) and the light stabilizer (B) to the vinyl chloride resin is 100% by weight of the resin.
It is preferable that the total amount of (A) and (B) is in the range of 0.02 to 8 parts by weight, particularly 0.1 to 3 parts by weight. (A) and
If the compounding amount of (B) is more than 8 parts by weight, there is a possibility that it may be jetted through a dustproof coating and an antifogging coating which will be described later. Further, the mixing ratio of (A) and (B) is such that (A) / (B) is 15/1 to 1/15 by weight ratio in order to maintain the durability of the agricultural film.
It is preferable to be in the range of, especially in the range of 8/1 to 1/8. Of course, in the agricultural soft vinyl chloride resin film of the present invention, if necessary, other resin additives, for example, antioxidants, heat stabilizers, antifogging agents, lubricants, pigments, dyes, inorganic fillers, organic A filler, a fluorescent agent, an infrared absorbing agent and the like can be blended and contained.

(5) A soft vinyl chloride resin film (hereinafter referred to as a base film), which is a base of an agricultural film of the present invention, is formed by adding a resin composition obtained by adding a necessary resin additive to a vinyl chloride resin into a ribbon. After homogenizing with a blending machine such as a blender, a Banbury mixer or a super mixer, and a kneading machine, an ordinary film manufacturing method such as a calender molding method, an extrusion molding method or an inflation film molding method is used to obtain 0.03 to 0.3 mm, preferably 0.0
Molded to a thickness of 75-0.25 mm.

(6) A coating derived from the fluororesin coating composition is formed on one surface of the base film. This is used because it is suitable for preventing surface contamination of the antifogging coating which is the contact surface when the product form is in a rolled state.

Examples of the fluorine-based resin that can be used in the present invention include homopolymers such as vinyl fluoride, vinylidene fluoride, ethylene trifluoride chloride, and tetrafluoroethylene: tetrafluoroethylene-ethylene, ethylene trifluoride chloride. -Ethylene,
Copolymer of tetrafluoroethylene-6-fluoropropylene, tetrafluoroethylene-perchloroalkyl vinyl ether, etc .: Fluoroalkyl acrylate random homopolymer: Fluoroalkyl acrylate Alkyl (meth) acrylate block copolymer: Fluoroolefin -Hydrocarbon-based vinyl ether monomer alternating copolymer: Copolymer composed of two or more kinds of monomers selected from the above fluorine-based monomers: One or more kinds selected from the above-mentioned fluorine-based monomers Copolymer consisting of a monomer and a fluorine-free copolymerizable monomer: a polymer obtained by partially modifying or modifying the above-mentioned fluorine-containing polymer: In addition, there is a mixture of the above-mentioned fluorine-containing polymer, etc. . Of these fluorine-based resins, vinylidene fluoride-based resin is particularly preferable.

The vinylidene fluoride resin is a homopolymer of vinylidene fluoride, or a copolymer of vinylidene fluoride and another fluorine-based unsaturated monomer and / or a fluorine-free copolymerizable monomer, Further, a polymer obtained by modifying or modifying a part of these polymers is included.

These vinylidene fluoride-based resins may be used alone or in combination of two or more, and may be used as a mixture with other fluorine-containing resin and / or fluorine-free resin.

The fluorine-free resin is, for example, an acrylic resin,
Epoxy resins, urethane resins, amino resins (alkyd resins, melamine alkyd resins, etc.) resins, alkylphenol resins, organosiloxane resins, etc. are listed, among which acrylic has good adhesion to the substrate surface. It is suitable as a resin to be mixed with a system resin. When a resin containing no fluorine is mixed, the mixing ratio is preferably 40 parts by weight or less based on 100 parts by weight of the fluorine-based resin in terms of solid content weight ratio.

Auxiliary components such as an antioxidant, a neutralizing agent, an ultraviolet absorber, a light stabilizer, an antistatic agent, a pigment, a dye and a lubricant can be added to the above coating composition.

The coating composition can be used by dispersing and / or dissolving it in an organic solvent.

The organic solvent is particularly preferably, for example, acetone, tetrahydrofuran, methylethylketone, dimethylformamide, dimethylacetamide, tetramethylurea, trimethylphosphate, or the like, and preferable ones are, for example, methylisobutylketone, ethyl acetate,
There are butyl acetate, cyclohexanone, diacetone alcohol, diisobutyl ketone, γ-butyrolactone, tetraethylurea, isophorone, diethylene glycol monoethyl ether acetate, propylene carbonate, dimethyl phthalate, etc., which can be used alone or in combination of two or more kinds. it can. If the amount used is small,
For example, heptane, cyclohexane and other aliphatic hydrocarbons, benzene, toluene, xylene and other aromatic hydrocarbons, methanol, ethanol, isopropyl alcohol and other alcohols, chloroform, tetrachlorohydrocarbons and other halogenated hydrocarbons, etc., alone or in combination of two or more. Can be used in combination.

The coating amount in the case of a film by applying the coating composition to the surface of the soft vinyl chloride resin base film, a coating method, as the amount after drying and solidification, the 0.1g / m ² ~10g / m ² It is preferably in the range. If the amount is less than 0.1 g / m ^2, the effect of preventing surface contamination of the antifogging film which becomes the contact surface in the wound state is insufficient. On the other hand, if it is 10 g / m ² or more, the coating amount becomes too large, which is economically disadvantageous, and the mechanical strength of the film itself may decrease. Therefore, usually
Range of 0.5g / m ² ~5g / m ² is most preferred.

(7) The antifogging agent composition for forming an antifogging film on the other surface of the base film contains silica and / or alumina sol as a main component, and a binder component of silica or alumina is mixed therein.

The colloidal silica and / or alumina sol preferably has an average particle size in the range of 5 to 100 mμ. If the average particle size exceeds 100 mμ, the coating film is white and easily devitrifies. 5
If it is less than mμ, the stability of the antifogging composition is insufficient, which is not preferable. These may be used alone or in combination of both. Further, when used alone or in combination of two, two or more kinds having different average particle diameters may be used in combination. When both are combined, the weight ratio of colloidal silica / alumina sol is 95-
The ratio is preferably 5/5 to 95 (total 100).

The alumina sol may be either a commercially available product itself or an aqueous sol prepared by dispersing usually commercially available alumina powder in water. Alumina sol exhibits a so-called thixotropic property that the viscosity of the dispersion rapidly increases when it is dispersed in water at a high concentration, and it is difficult to obtain a uniform dispersion, but if a medium shear internal stirrer such as a colloid mill is used. , A homogeneous dispersion can be obtained. Further, by mixing colloidal silica with this dispersion, the viscosity of the dispersion can be lowered.

On the other hand, the colloidal silica is often negatively charged on the particle surface in many cases, but it is not preferable to use the negatively charged one when used in combination with alumina sol. This is because, when colloidal silica and alumina sol are mixed, the mixed dispersion liquid rapidly agglomerates and gels, resulting in poor dispersion. Therefore, the colloidal silica is preferably positively charged on the particle surface.

It is necessary to select a binder component having a good affinity with a hydrophilic medium such as water or alcohol, which is a dispersion medium of alumina sol or silica sol, as a binder component to be blended with the antifogging agent composition. Specifically, a surfactant or a thermoplastic resin having such an affinity is used.
It is necessary to change the type of surfactant used depending on the colloidal silica or alumina sol. For example, in general, a combination of negatively charged silica sol and a cationic surfactant and a combination of positively charged alumina sol and anionic surfactant should be avoided. These combinations easily cause gelation of the sol and aggregation / separation of the antifogging agent composition, which makes application difficult.

As the thermoplastic resin used as the binder component,
As described above, an acrylic resin, vinyl chloride-vinyl acetate resin, polyethylene resin, vinyl chloride resin, vinylidene chloride resin, which has a good affinity with a medium (usually water),
Polyurethane-based resins, polycarbonate-based resins, styrene-based resins, vinyl acetate-based resins, unsaturated polyester-based resins and the like can be mentioned, with acrylic-based resins being particularly preferred.

The amount of the colloidal silica and / or alumina sol, which is the main component of the antifogging agent composition, is preferably in the range of 0.5 to 40 times the binder component in terms of solid content weight ratio.
When it exceeds 40 times, not only the antifogging effect does not improve in proportion to the compounding amount, but also the phenomenon that the coating film formed after coating becomes cloudy and the light transmittance decreases. Further, the coating film tends to be rough and brittle. On the other hand, 0.
When it is less than 5, it becomes difficult to exert a sufficient antifogging effect.

A crosslinkable compound that crosslinks the binder components may be used in combination with the antifogging composition. By doing so, the water resistance of the anti-fog coating can be improved. As the crosslinkable compound, the same compounds used in the above-mentioned antifog coating composition can also be used in the antifog composition.
The amount of the crosslinkable 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 preferred.

If necessary, the antifog composition may be mixed with an antifoaming agent, a lubricant, an antistatic agent, and various other additives.

Thus, the antifogging composition is usually used in liquid form. The liquid dispersion medium includes an affinity or water-miscible solvent containing water, water; methyl alcohol, ethyl alcohol,
Examples include monohydric alcohols such as isopropyl alcohol; polyhydric alcohols such as ethylene glycol, diethylene glycol and glycerin; cyclic alcohols such as benzyl alcohols; cellosolve acetates; ketones.

These may be used alone or in combination, but in consideration of the dispersion stability of the antifogging composition used in the present invention, the wettability after coating on the film surface, the difficulty of removing the liquid dispersion medium, and the economical efficiency. It is preferable to decide.

The coating of the antifogging agent composition formed on the surface of the base film generally has a solid content of 0.01 to 10 g /
It is preferably in the range of m ² , especially 0.1 to 5 g / m ² .

In order to form a film of a fluororesin coating composition and an antifogging composition on the surface of a base film, a solution or dispersion of each composition is generally doctor blade coating method, roll coating method, dip coating method, spray coating. A coating method known per se, such as a coating method, a rod coating method, a bar coating method, a knife coating method, a brush coating method, etc., may be employed and dried after coating. In the case of a fluororesin coating composition, the drying method after coating needs to be heated and dried in view of the physical properties of the coating, and it is preferable to maintain the heating temperature in the range of 50 to 200 ° C. for 5 seconds to 10 minutes. In the case of the antifogging composition, either natural drying or forced drying may be adopted. When the forced drying method is adopted, it is usually 50 to 150 ° C, preferably 7 ° C.
It may be dried in the temperature range of 0 to 130 ° C. Any appropriate method such as a hot-air drying method, an infrared drying method, or a far-infrared drying method may be adopted for the heat drying, and the hot-air drying method is advantageous in view of the drying speed and safety.

Incidentally, the fluororesin coating composition does not make it a solution, but the composition itself is coextruded with a base film,
Alternatively, it may be formed into a film by extrusion coating on a base film, extrusion lamination or the like.

The order of forming the coating film of the fluororesin coating composition and the antifogging agent composition on the surface of the base film is determined in consideration of heating conditions and the like.

Further, when the adhesion between the base film and the coating film derived from both compositions is not sufficient, the surface of the base film is previously washed with alcohol or water, plasma discharge treatment, corona discharge treatment, or other Pretreatment such as undercoating with a paint or a primer may be performed.

"Effects of the Invention" The present invention has particularly remarkable effects as described below, and its industrial utility value is extremely large.

(1) The agricultural soft vinyl chloride resin film according to the present invention has a film derived from the antifogging agent composition formed on one surface of the film, and the film of the antifogging agent composition is housed on the film. When it is spread inside, etc., it has the function of suppressing the attachment of water drops, and the antifogging effect continues for a long time.

(2) In the agricultural soft vinyl chloride resin film according to the present invention, an antifogging film is formed on one surface of the film, and a film derived from the fluorine resin composition is formed on the other surface of the film. ing. Therefore, even if the film is stored in a rolled state for a long time, the surface of the anti-fog coating is not contaminated, and the desired excellent anti-fog effect is retained.

"Example" Next, the present invention will be described in detail based on Examples,
The present invention is not limited to the following examples as long as the gist thereof is not exceeded.

Examples 1-5, Comparative Examples 1-5 (1) Preparation of base film Polyvinyl chloride (= 1400) 100 parts by weight Dioctyl phthalate 50 〃 Tricresyl phosphate 5 〃 Epoxidized soybean oil 1 〃 Ba / Zn-based composite Stabilizer 1.5〃 barium stearate 0.2〃 zinc stearate 0.4〃 sorbitan monolaurate 1.5〃 2,4-dihydroxybenzophenone 0.6〃 bis (2,2,6,6-tetramethyl 0.4〃-4-biperidyl) sebacate The above mixture was stirred and mixed with a super mixer for 10 minutes, and then kneaded on a mill roll heated to 180 ° C.
A substrate film roll having a thickness of 0.15 mm was prepared.

(2) Formation of coating film of fluororesin coating composition Mixtures of fluororesin of the types and amounts shown in Table 1 were added with methyl ethyl kent so that the solid content was 20% by weight, and the coating composition I got a thing. However, in Comparative Example 4, no fluorine resin was blended.

Each coating composition was continuously coated on one side of the substrate film prepared by the method (1) by a roll coating method, and the coating film was kept at 130 ° C. for 1 minute in a drying oven to volatilize the solvent and heat treatment at the same time. And each film was wound. The coating amount of each film obtained was about 2 g / m ² . However, in Comparative Examples 1 and 2, the coating film derived from the fluororesin composition was not formed.

(3) Formation of Film of Antifogging Agent Composition The main ingredients (colloidal silica and / or alumina sol) shown in Table 1 are mixed with a binder component, a crosslinking agent and a liquid dispersion medium to obtain an antifogging agent composition. It was However, in Comparative Example 5, no main component was added.

The above antifogging agent composition was continuously applied to the other surface of the base film having the fluororesin coating film formed thereon by a roll coating method and kept at 80 ° C. for 1 minute in a drying oven to volatilize the liquid dispersion medium. Each film was wound. The coating amount of each film obtained was about 1 g / m ² .

In addition, in Comparative Examples 1, 3, and 5, a coating film derived from the antifogging agent composition was not formed.

(4) Evaluation of Film The performance of the soft vinyl chloride resin film for agriculture was evaluated by the following method, and the results are shown in Table 2.

Anti-fog property Ten types of film rolls produced were stored at 30 ° C for 1 month, then rewound and installed in a test field in Isshi-gun, Mie prefecture.
m, roof slope 30 degrees) with the coating of the antifogging composition on the inside. Then, the state of water droplets adhering to the surface of the anti-fog coating was visually observed with time. The evaluation criteria are as follows.

A: Water droplets adhering to the film surface (the one facing the inside of the house) coalesces and spreads into a thin film, and the area of this thin film portion covers more than 1/2 of the film surface (same as above).

Good: Water droplets adhering to the film surface (same as above) coalesce and spread in a thin film form, but the area of this thin film part is less than 1/2 of the film surface (same as above).

Δ: Water droplets adhering to the film surface (same as above) are recognized, but the shape of the thin film portion is not recognized.

X: Water droplets adhering to the film surface (same as above) are not recognized as coalescing.

The following is clear from Table 2.

(1) In Comparative Example 1 and Comparative Example 3, the antifogging property was good at the initial stage, but the deterioration after that was remarkable and it was inferior.

(2) In Comparative Examples 2 and 4, the antifogging property is good in the initial stage, but the long-term sustainability is not sufficient.

(3) Comparative Example 5 is inferior in antifogging property from the beginning.

(4) On the contrary, the agricultural soft vinyl chloride resin film of the present invention has excellent anti-fogging property even when used for a long period of time, and has an optimal structure as an agricultural film.

Claims (1)

[Claims] 1. A soft vinyl chloride resin film on one side,
A film derived from a fluororesin coating composition is formed, and a film derived from an antifogging agent composition containing colloidal silica and / or alumina sol and a binder as main components is formed on the other surface of the film. A soft vinyl chloride resin film for agriculture.