JPH06344522A - Agricultural soft vinyl chloride base resin film - Google Patents

Abstract

PURPOSE:To enhance the anti-fogging properties and dust-proof properties at the time of long-term stretching by forming a coating film containing an acrylic resin modified with vinyl group-containing alkoxysilane and vinyl group- containing polysiloxane as effective component on both surfaces of an agricultural soft vinyl chloride base resin film compounded with a surfactant and having antifogging properties in specific thickness. CONSTITUTION:An agricultural soft vinyl chloride base type resin film compounded with a surfactant and having anti-fogging properties is used as a base material. A coating film composed of a coating material containing a silicone modified acrylic resin obtained by copolymerizing 0.5-20wt.% of vinyl group-containing alkoxysilane, 0.1-20wt.% of vinyl group-containing polysiloxane, 10-30wt.% of acrylic ester or methacrylic ester having a hydroxyl group and 40-80wt.% of methacrylic ester and/or acrylic ester having a 1-12C ester group as an effective component is formed on both surfaces of the base material so that the thickness thereof is 0.2-1.0mum on one surface of the base material and 1.0-5.0mum on the other surface thereof.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an agricultural flexible vinyl chloride resin film having excellent durability, which is useful as an agricultural soft covering material for greenhouses and greenhouses for facility cultivation of plants.
More specifically, the present invention relates to a flexible vinyl chloride resin film for agriculture which has excellent antifogging properties, dustproof properties, and weather resistance for a long period of time even after being spread.

[0002]

2. Description of the Related Art Generally, agricultural films used for plant cultivation of plants include vinyl chloride resin (PVC), branched low-density polyethylene (LDPE), linear low-density polyethylene (LLDPE), and ethylene-vinyl acetate. There is a soft plastic film having a thickness of 30 to 200 μm made of a copolymer (EVA) or the like. Among them, the soft vinyl chloride resin film is widely used because it has an excellent balance of light transmittance, heat retention and mechanical strength, and is economical.

However, when a soft vinyl chloride resin film is used as an agricultural film and a plant is cultivated satisfactorily, the film is inferior in antifogging performance and dustproof performance. Therefore,
Conventionally, these improvements have been actively made. Anti-fog property is the performance of water droplets attached to the inner surface of the agricultural film during cultivation, which reduces the light transmittance, adversely affects crop growth, or suppresses the occurrence of disease, and dust resistance. Dust adheres to the outer surface of the agricultural film and stains the film to reduce the light transmittance, which adversely affects crop growth and suppresses the occurrence of diseases.

As a method for imparting antifogging property to an agricultural film, (i) a method of blending a surfactant, (ii) a method of coating a hydrophilic polymer compound solution on the surface to form a coating film, etc. However, it is generally adopted. In the method (i), since the surfactant gradually migrates to the surface of the film, the wettability of the surface of the film is improved, and water droplets that adhere can be made to flow down along the film. Although it has excellent anti-fogging properties, the surfactant migrated to the surface of the film is easily washed away by water droplets,
There is a problem that the period in which the surfactant is present on the film is short and the antifogging property does not last for a long time (hereinafter referred to as antifogging durability). Further, in the method (ii), since the hydrophilic polymer originally has poor water resistance, the coating film swells due to water droplets attached to the surface of the film, resulting in poor adhesion between the coating film and the base film. Then, the water drops peel off the coating film from the surface of the base material film and flow down, so that there is a problem that the initial anti-fog property is good, but the long-term sustainability is poor.

As a method of imparting dustproofness to an agricultural film, a method of treating the surface of the film with an acrylic resin has been proposed and put to practical use (Japanese Patent Publication No. 62-62).
-16187). However, to make the acrylic resin and the soft vinyl chloride resin film have the same flexibility and cold resistance so that the acrylic resin does not crack during work, the glass transition temperature of the acrylic resin is (Tg) should be lowered. However, when the Tg becomes low, it causes stickiness and blocking when the film is exposed to high temperature. In particular, stickiness and blocking during summer stretch use are major obstacles in opening and closing work, and improvement thereof is desired.

[0006]

An object of the present invention is to solve the above problems and impair the transparency, flexibility, cold resistance, weather resistance and mechanical properties required for agricultural films. It is an object of the present invention to provide a soft vinyl chloride resin film for agriculture, which has excellent antifogging durability and dustproof property and is suitable for long-term spreading without stickiness or blocking.

[0007]

[Means for Solving the Problems] The inventors of the present invention have made extensive studies on the above-mentioned problems, and have vinyl group-containing alkoxysilanes on both sides of a soft vinyl chloride resin film for agricultural use having a surface active agent and having antifogging properties. The inventors have found that the problem can be solved by forming a coating film made of a coating material containing an acrylic resin modified with a vinyl group-containing polysiloxane as an active ingredient to have a specific thickness, and arrived at the present invention. That is, the present invention uses, as a base material, an agricultural soft vinyl chloride resin film having an antifogging property, which is mixed with a surfactant, and has vinyl group-containing alkoxysilanes of 0.5 to 2 on both surfaces of the base material.
0% by weight, vinyl group-containing polysiloxane 0.1-20
Obtained by radical copolymerization of 50% by weight, acrylic acid ester or methacrylic acid ester having a hydroxyl group, 10 to 30% by weight, and methacrylic acid ester and / or acrylic acid ester having an ester group having 1 to 12 carbon atoms. A coating film made of a coating material containing a silicone-modified acrylic resin as an active ingredient and having a thickness of 0.2 on one surface.
To 1.0 μm and a thickness of 1.0 to 5.0 μm on the other surface, which is a soft vinyl chloride resin film for agriculture.

The silicone-modified acrylic resin according to the present invention can be obtained by mixing the following monomers in a specific ratio and carrying out a copolymerization reaction, but sufficiently exhibits the intended function of the present invention. For this purpose, vinyl group-containing alkoxysilane 0.5 to 20% by weight, vinyl group-containing polysiloxane 0.1 to 20% by weight, hydroxyl group-containing acrylic ester or methacrylic ester 10
It is necessary to copolymerize the methacrylic acid ester and / or the acrylic acid ester in the range of ˜30 wt% and 40-80 wt%.

If any one of the monomers (1) to (4) is out of the above range, the desired function of the present invention will not be sufficiently exhibited. The same applies when the amount of the monomer used is larger than the above range. When the amount of the monomer used is less than the above range, the basic physical properties of the acrylic resin coating film are lost.

The vinyl group-containing alkoxysilane which is a monomer of

[0011]

[Chemical 1]

A silane compound represented by: Specific groups for R ² include

[0013]

[Chemical 2]

And the like. As a specific group of X,

[0015]

[Chemical 3]

And the like. Specific examples of the vinyl group-containing alkoxysilane include methacryloxypropyltrimethoxysilane and vinyltrimethoxysilane. The vinyl group-containing polysiloxane of

[0017]

[Chemical 4]

A polysiloxane having a vinyl group at one end represented by:

[0019]

[Chemical 5]

A polysiloxane having vinyl groups at both ends represented by (R ² is the same as R ² of the alkoxy silane)

Specific examples of the vinyl group-containing polysiloxane include vinyl dimethyl polysiloxane having both ends or one end and methacryl dimethyl polysiloxane having both ends or one end. The viscosity range of these polysiloxanes is preferably 5 to 30,000 cp, and the molecular weight is preferably 200 to 100,000.

Specific examples of the acrylic acid ester or methacrylic acid ester having a hydroxyl group, which is the monomer of, are methyl 2-hydroxyacrylate, ethyl 2-hydroxyacrylate, butyl 2-hydroxyacrylate, and 2-hydroxyacryl. Allyl acid phenyl 2-hydroxyacrylate, methyl 2-hydroxymethacrylate, ethyl 2-hydroxymethacrylate, pentyl 2-hydroxymethacrylate, butyl 2-hydroxymethacrylate, allyl 2-hydroxymethacrylate, 2-hydroxymethacrylic acid Examples include vinyl.

The number of carbon atoms of the ester group, which is a monomer of 1, is 1
Specific examples of the methacrylic acid ester and / or acrylic acid ester of to 12 include methyl acrylate, ethyl acrylate, butyl acrylate, allyl acrylate,
Examples thereof include phenyl acrylate, methyl methacrylate, ethyl methacrylate, butyl methacrylate, pentyl methacrylate, lauryl methacrylate, vinyl methacrylate, allyl methacrylate, and the like, which are a combination of two or more of these monomers. It doesn't matter.

In order to copolymerize the monomer mixture (1) to (3), an organic acid having 3 or more carbon atoms is added in an amount of 0.1 to 5% by weight with respect to the mixture for polymerization (total amount of "Note"). Preference is given to using. In addition, the total amount of all radical monomers represented by benzoyl peroxide and azobisisobutyronitrile (Note.
On the other hand, 0.1 to 3% by weight, preferably 0.2 to 2% by weight may be added. As the polymerization method, bulk polymerization,
Although any of solution polymerization can be carried out, it is most preferable because solution polymerization can be easily applied as a coating material after completion of the polymerization. The polymerization conditions are not particularly limited, but usually, the temperature is 60 to 150.
It can be obtained at a temperature of 2 to 10 hours.

The degree of polymerization of the silicone-modified acrylic resin according to the present invention can be adjusted by the type and amount of the polymerization catalyst or the addition of a chain transfer agent. In solution polymerization using an organic solvent, the total amount of monomers is On the other hand, a certain ratio of solvent is used, and the degree of polymerization is adjusted after completion of the polymerization so that the viscosity range is suitable for the production of coating materials. A preferred viscosity range is 50 to 1000 cp (25 ° C.), more preferably 100 to 500 cp (25 ° C.) in a polymer concentration of 30 wt% isopropyl alcohol solvent, and a preferred weight average molecular weight (styrene standard) is 10,000 to 120.
000 is good.

The organic solvent used for solution polymerization is selected from those having a certain degree of solubility in solutes (diluting during reaction, adjusting viscosity) and having good dryness after coating. As the solvent, alcohols are preferable, and specific examples thereof include methanol, ethanol, isopropyl alcohol, n-butanol, isoamyl alcohol and the like. Further, in order to adjust the viscosity of the coating material and the drying rate after coating, a small amount (20% or less of the total coating material) of a solvent, for example, an aromatic compound such as toluene or xylene, an ester such as ethyl acetate or butyl acetate. The compounds and ketones such as acetone and methyl ethyl ketone may be mixed.

The coating film according to the present invention is formed on both sides of the base film. Since one side has a surface having antifogging property, the thickness of the coating film must be adjusted.
When the thickness is less than 0.2 μm, it is difficult to obtain a coating film having a uniform thickness, and it becomes easy for the surfactant to pass through the coating film. It will be exhausted. On the other hand, when the thickness exceeds 1.0 μm, the surfactant cannot pass through the coating film, so that the coating film cannot be provided with antifogging property. In order for the surfactant to gradually pass through the coating film and have a sustained release effect of imparting antifogging property on the coating film for a long period of time, the average thickness of the coating film is set to 0.2 to 1.0 μm. Preferably 0.4
.About.1.0 .mu.m is necessary. To make the other surface dustproof, the thickness of the coating film is 1.0 to 5.0 μm,
It should preferably be 1.2 to 4.0 μm.
If the thickness is less than 1.0 μm, the dustproof property is insufficient and the durability is shortened. If the thickness exceeds 5.0 μm, the mechanical strength of the film on which the coating is formed is reduced, and both are not preferable.

The method for forming the coating film on the substrate film is not particularly limited, and the coating material is coated with the coating material using a known means such as a gravure coater, a roll coater, a blade coater or a bar coater. A coating film having a uniform thickness can be obtained by uniformly adhering it to the film, heating and drying the coated film to evaporate the solvent contained in the coating material. The drying temperature is appropriately adjusted depending on the solvent used, but is usually 80 to 120 ° C. and 0.5 to
About 10 minutes is sufficient. Furthermore, the coating film after drying may be added in an amount of 20 to 50, if necessary, in order to complete the curing.
Hold at ℃ for 7-14 days.

The base film according to the present invention is obtained by molding a soft vinyl chloride resin composition containing a vinyl chloride resin, a plasticizer and a surfactant into a film. Vinyl chloride resin is a vinyl resin mainly composed of vinyl chloride homopolymer and vinyl chloride, and vinyl chloride and other copolymerizable monomers such as vinyl acetate, vinylidene chloride, ethylene, propylene, and acrylic acid ester. And a copolymer thereof. These may be those obtained by a conventionally known polymerization method (suspension polymerization, emulsion polymerization, bulk polymerization, etc.).

As the plasticizer, di-2-ethylhexyl phthalate, diisodecyl phthalate, diisononyl phthalate,
Examples thereof include di-2-ethylhexyl adipate, epoxidized soybean oil, epoxy resin and the like, and the compounding amount of the plasticizer is preferably in the range of 40 to 60 parts by weight with respect to 100 parts by weight of the vinyl chloride resin.

Examples of the surfactant include nonionic surfactants such as polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan monopalmitate, glycerin monostearate and diglycerin monostearate, which are used alone. Alternatively, two or more kinds may be used in combination, and the blending amount thereof is preferably in the range of 0.5 to 3.0 parts by weight with respect to 100 parts by weight of the vinyl chloride resin.

The soft vinyl chloride resin composition according to the present invention contains a vinyl chloride resin, a plasticizer and a surfactant, and if necessary, a stabilizer, a stabilizing aid, an antioxidant, a lubricant and an ultraviolet absorber. Agents, colorants and the like can be added.
Examples of the stabilizer include metal soap stabilizers such as calcium stearate, barium stearate, zinc stearate, and barium laurate; organotin stabilizers such as dibutyltin dilaurate and dibutyltin mercaptide; Examples of the chemical auxiliaries include phosphite esters such as triphenyl phosphite, tri-2-ethylhexyl phosphite, and trinonylphenyl phosphite. Examples of the antioxidant include t-butylhydroxytoluene, dilaurylthiodipropionate, and the like, and examples of the lubricant include stearic acid, stearic acid amide, polyethylene wax, and the like.
Examples of the ultraviolet absorber include 2- (5-methyl-2)
-Hydroxyphenyl) benzotriazole, 2- (3
-T-butyl-5-methyl-2-hydroxyphenyl)
Examples include -5-chlorobenzotriazole and the like, and examples of the colorant include phthalocyanine blue, titanium oxide, carbon black and the like.

The soft vinyl chloride resin composition according to the present invention can be formed into a film by a conventional method, for example, a calender method, an extrusion method (T-die method, inflation method), etc. It is obtained by processing to a thickness of 200 μm. The agricultural soft vinyl chloride resin film of the present invention is such that the surface having antifogging property is always on the inner side (inner surface) of the house or tunnel, and the surface having dustproof property is always on the outer side (outer surface). Is installed in this way.

[0034]

EXAMPLES The present invention will be specifically described below with reference to Examples and Comparative Examples, but the present invention is not limited thereto. The physical properties of the molded articles in Examples and Comparative Examples were measured by the following methods. Test method 1) Anti-fogging sustainability 200 cc of water is put into a beaker of 300 cc, and the test film is covered so that the anti-fog surface is the inner surface of the beaker and fixed with a rubber band. Next, the beaker is fixed in a water bath so that the water surfaces of the beaker and the bath are the same, and the water temperature is kept at 40 ° C. In this state, the state of water droplets on the film surface is checked at regular intervals (1,
It was examined every 2 to 4 months) and evaluated in the following 5 grades. The larger this value is, the better the antifogging sustainability is. Evaluation 5 Water drop adhesion area on the film inner surface is less than 10% Evaluation 4 〃 10-20% Evaluation 3 〃 20-30% Evaluation 2 〃 30-50% Evaluation 1 〃 50% or more

2) Dustproofness (stickiness peeling test) Several test films were cut into 50 mm × 120 mm,
Dust-proof surfaces of two test films should be
mm × 50 mm are partially overlapped, and a load of 1 kg is applied thereon, and the mixture is heated in an oven at 70 ° C. for 2 hours.
Then, the load was removed, the mixture was allowed to stand at room temperature for 24 hours, and the adhesion strength of the two laminated films was measured by peeling 180 degrees with a strograph (manufactured by Toyo Seiki). The higher the strength is, the worse the stickiness is, and the lower the dust resistance is. 3) Outdoor exposure test House (tunnel type, length 2 m, with the surface having antifogging property of the test film inside and the surface having dustproof property outside)
The film was spread to a diameter of 1 m), and the antifogging property and dustproof property of the film were measured. The evaluation test was carried out by the following method by using the product stretched in Kumamoto prefecture for 24 months. Anti-fog property Anti-fog dripping property (water droplets run off,
Performance that does not remain as water drops on the film surface. ) Was observed. The observation criteria were as follows. ○ Good anti-fog dripping property △ Slightly good anti-fog dripping property × Poor anti-fog dripping property Dust proofness A sample was taken from the film spread for 24 months, and the haze value of the test film was measured by a haze meter (Nippon Denshoku) It was measured at. The smaller the number, the better.

Example 1 (Preparation of coating material) In a three-necked flask, 42.5 parts by weight of methyl methacrylate and 18.0 parts of 2-hydroxyethyl methacrylate were added to 100 parts by weight of isopropyl alcohol kept at 80 ° C. Parts by weight, n-butyl methacrylate 2
7.5 parts by weight, n-butyl acrylate 5.0 parts by weight, 3
5.0 parts by weight of methacryloxypropyltrimethoxysilane, 1.0 part by weight of methacryloxydimethylpolysiloxane at one end (Mw = 5000), 1.0 of methacrylic acid
A monomer mixture for polymerization consisting of 1 part by weight and 1.0 part by weight of benzoyl peroxide was added dropwise and allowed to react for 5 hours, and then 0.5 part by weight of benzoyl peroxide was added and the mixture was heated at 80 ° C. for 4 hours.
The reaction was carried out for a time to obtain a silicone-modified acrylic resin solution having a molecular weight of about 70,000 (Note: resin content concentration 50% by weight). A mixed solvent of isopropyl alcohol and ethyl acetate (weight ratio: 3/1) was added to this solution to adjust the solid content concentration to 20% by weight to prepare a coating material.

(Preparation of film) 100 parts by weight of vinyl chloride resin (average degree of polymerization: 1300) was added with phthalic acid di-2.
-Ethylhexyl 40 parts by weight, tricresyl phosphate 5 parts by weight, epoxidized soybean oil 3 parts by weight, barium-zinc complex stabilizer 1.5 parts by weight, methylenebisstearic acid amide 0.5 parts by weight, sorbitan monopalmitate. After mixing 2.5 parts by weight and uniformly mixing with a Henschel mixer (trade name), a thickness of 100 μ was obtained by a calendar method.
m film was made. The coating material is applied to one surface (the surface having antifogging property) of this film by a gravure coater method, and dried in a hot air drying oven at 80 to 100 ° C. for 30 seconds,
A 0.8 μm coating film was formed. Then, as the other surface of the film (the surface having dust resistance), 2.0 μm in the same manner.
The coating film of Example 1 was formed to obtain the film of Example 1. The obtained film was used as a test film and evaluated using the method described above. The results are shown in Table 1.

Example 2 (Preparation of coating material) 27.5 parts by weight of lauryl methacrylate in place of n-butyl methacrylate, one end of methacryloxydimethylpolysiloxane with Mw = 5000, and one end of methacrylic acid with Mw = 1000. A silicone-modified acrylic resin solution having a molecular weight of about 65,000 (note that the resin content concentration was 50% by weight) was obtained according to Example 1 except that 1.0 part by weight of roxydimethylpolysiloxane was used. I got a coating material. (Production of Film) A test film of Example 2 was obtained in the same manner as in Example 1 except that the above coating material was used. The obtained film was evaluated in the same manner as in Example 1, and the results are shown in Table 1.

Comparative Example 1 (Preparation of coating material) According to the same manner as in Example 1 except that 5.0 parts by weight of 3-methacryloxypropyltrimethoxysilane was not used, a modified acrylic resin solution having a molecular weight of about 70,000 (Note: resin content) A concentration of 50% by weight) was obtained, and a coating material was obtained according to Example 1. (Production of Film) A test film of Comparative Example 1 was obtained in the same manner as in Example 1 except that the above coating material was used. The obtained film was evaluated in the same manner as in Example 1, and the results are shown in Table 1.

Comparative Example 2 (Preparation of Coating Material) Silicon-modified acrylic resin solution having a molecular weight of about 83000 in accordance with Example 1 except that 1.0 part by weight of methacryloxydimethylpolysiloxane (Mw = 5000) at one end was not used. (Note: Resin content concentration: 50% by weight) to obtain a coating material according to Example 1. (Production of Film) A test film of Comparative Example 2 was obtained in the same manner as in Example 1 except that the above coating material was used. The obtained film was evaluated in the same manner as in Example 1, and the results are shown in Table 1.

Comparative Example 3 (Preparation of coating material) Example except that 5.0 parts by weight of 3-methacryloxypropyltrimethoxysilane and 1.0 part by weight of methacryloxydimethylpolysiloxane (Mw = 5000) at one end were not used. A modified acrylic resin solution having a molecular weight of 88,000 (Note: resin content concentration: 50% by weight) was obtained according to Example 1, and a coating material was obtained according to Example 1. (Production of Film) A test film of Comparative Example 3 was obtained in the same manner as in Example 1 except that the above coating material was used. The obtained film was evaluated in the same manner as in Example 1, and the results are shown in Table 1.

Comparative Example 4 (Preparation of Film) Sorbitan Monopalmitate 2.5
Comparative Example 4 according to Example 1 except that no parts by weight are used.
I got a film of. The obtained film was evaluated in the same manner as in Example 1, and the results are shown in Table 1.

Comparative Example 5 (Production of film) The test film of Comparative Example 5 according to Example 1 except that the coating film formed on one surface of the film (the surface having antifogging property) was 1.5 μm. Got The obtained film was evaluated in the same manner as in Example 1, and the results are shown in Table 1.

Comparative Example 6 (Preparation of Film) A test film of Comparative Example 6 was prepared according to Example 1 except that the coating film formed on one surface (the surface having dustproofness) of 0.8 μm. Obtained. The obtained film was evaluated in the same manner as in Example 1, and the results are shown in Table 1.

Comparative Example 7 (Preparation of Film) A test film of Comparative Example 7 was obtained according to Example 1 except that the coating film was not formed on the base film. The obtained film was evaluated in the same manner as in Example 1, and the results are shown in Table 1.

[0046]

EFFECTS OF THE INVENTION From the above results, the agricultural soft vinyl chloride resin film of the present invention has an antifogging property and a dustproof property during long-term spreading which cannot be achieved by the conventional general agricultural film and acrylic treated agricultural film. It was found to significantly improve the above. Therefore, it is suitable for long-term extension and its utility value is extremely large.

[0047]

[Table 1]

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Internal reference number FI Technical indication C09D 143/04 PGL 157/00 PGZ B29K 27:06

Claims (1)

[Claims] Claims: 1. A soft vinyl chloride resin film for agriculture, which has an antifogging property and contains a surfactant, is used as a base material, and 0.5 to 20 vinyl group-containing alkoxysilanes are provided on both surfaces of the base material.
% By weight, vinyl group-containing polysiloxane 0.1-20% by weight, hydroxyl group-containing acrylic ester or methacrylic acid ester 10-30% by weight, ester group having 1-12 carbon atoms and / or acrylic acid A coating film comprising a coating material containing a silicone-modified acrylic resin obtained by radical copolymerization of 40 to 80% by weight of an ester as an active ingredient and having a thickness of 0.2 to
A soft vinyl chloride resin film for agriculture, which is formed to have a thickness of 1.0 μm and a thickness of 1.0 to 5.0 μm on the other surface.