JP2001220480A - Agricultural vinyl chloride-based resin film - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prepare an agricultural vinyl chloride-based film excellent in weather resistance and having extremely small reductions of physical properties (elongation, strength and impact strength) at a low temperature. SOLUTION: This agricultural vinyl chloride-based film is characterized by incorporating 0.5-20 pts.wt. chlorinated polyethylene, 30-60 pts.wt. plasticizer and an ultraviolet light-absorbing agent in an amount capable of substantially inhibiting the transmission of the ultraviolet light having <=380 nm wave length.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vinyl chloride resin film for agricultural use. More specifically, it is excellent in strength and impact resistance at low temperatures, and has little adhesion when films overlap, and has excellent initial and long-term anti-fog properties after outdoor exposure, and excellent weather resistance. The present invention relates to a vinyl chloride resin film for agricultural use.

[0002]

2. Description of the Related Art In recent years, in order to efficiently cultivate useful plants, promotion cultivation in a house or a tunnel has been actively performed. As a material for covering the house or the tunnel, a vinyl chloride resin film is frequently used because of its excellent weather resistance, transparency, heat retention and the like.

[0003] However, a soft vinyl chloride resin film contains a plasticizer as a resin softener.
This plasticizer has high temperature sensitivity, and has poor elongation particularly when used in cold areas, and is easily broken. There is also a problem that the film is easily broken when an external force such as wind, snow, hail, or arare is applied to the film even after the expansion. For this reason, as a method of improving physical properties such as elongation and impact resistance in cold regions,
The following methods have been proposed for increasing the amount of a plasticizer in a vinyl chloride resin film for agricultural use, or for blending a plasticizer, such as blending a cold-resistant plasticizer.

It is known that a method of increasing the amount of plasticizer in a vinyl chloride resin film has an effect of improving low-temperature strength. However, in this method, the film becomes sticky at high temperatures such as in summer. It is known to sag or sag. Therefore, a method has been proposed in which a cold-resistant plasticizer is blended in order to improve the physical properties at low temperatures without increasing the amount of the plasticizer too much (JP-A-58-49742, etc.). However, this method generally has poor compatibility with a vinyl chloride resin, causing bleeding and poor heat resistance. Further, there is a defect that the weather resistance is poor (browning, etc.).

Further, there is known a technique in which a specific ultraviolet absorber is added in a large amount to a vinyl chloride resin film to substantially prevent transmission of ultraviolet rays (Japanese Patent Publication No. 53-4736).
3). However, in a conventional general vinyl chloride resin film, there is a problem that the physical properties are deteriorated when such a large amount of additives is added.

[0006]

SUMMARY OF THE INVENTION Under such circumstances, the present inventors have developed a vinyl chloride-based agricultural material which is excellent in weather resistance and has a remarkably small decrease in physical properties (elongation, strength, impact resistance) at low temperatures. It was intended to provide a resin film.

[0007]

The gist of the present invention is that 0.5 to 20 parts by weight of a chlorinated polyethylene, 100 parts by weight of a vinyl chloride resin and 3 parts of a plasticizer are used.
0 to 60 parts by weight of the vinyl chloride resin composition is blended with an amount of an ultraviolet absorber that substantially prevents transmission of ultraviolet light having a wavelength of 380 nm or less. Exist.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. 1. Vinyl Chloride Resin In the present invention, the vinyl chloride resin refers to not only polyvinyl chloride but also a copolymer containing vinyl chloride as a main component.
Examples of the monomer compound copolymerizable with vinyl chloride include vinylidene chloride, ethylene, propylene, acrylonitrile, maleic acid, itaconic acid, acrylic acid, methacrylic acid, and vinyl acetate. These vinyl chloride resins may be produced by any of conventionally known production methods such as an emulsion polymerization method, a suspension polymerization method, a solution polymerization method, and a bulk polymerization method.

In the present invention, the vinyl chloride resin having an average degree of polymerization of 1,000 to 2,500, preferably 1,100 to 2,000 is used.
Two types having different average polymerization degrees may be mixed.
This mixing method is generally a method of mixing two kinds of resins at the time of film forming process.
A method in which resins having different average polymerization degrees are mixed may be used.

In order to impart flexibility to the vinyl chloride resin film serving as the base, 30 to 60 parts by weight, preferably 40 to 55 parts by weight, per 100 parts by weight of the resin is used.
It is blended by weight. If the amount is less than 30 parts by weight, sufficient low-temperature physical properties cannot be obtained due to poor flexibility at low temperatures. On the other hand, if the amount exceeds 60 parts by weight, it is not preferable because handleability (stickiness, etc.) at normal temperature is deteriorated and workability during film forming processing is reduced.

Examples of the plasticizer that can be used include, for example, di-
phthalic acid derivatives such as n-octyl phthalate, di-2-ethylhexyl phthalate, dibenzyl phthalate and diisodecyl phthalate; isophthalic acid derivatives such as dioctyl phthalate; adipic acid derivatives such as di-n-butyl adipate and dioctyl adipate; di-n Maleic acid derivatives such as -butyl malate; citric acid derivatives such as tri-n-butyl citrate; itaconic acid derivatives such as monobutyl itaconate; oleic acid derivatives such as butyl oleate; ricinoleic acid derivatives such as glycerin monoricinoleate; Other examples include epoxidized large oils and epoxy resin plasticizers. Further, in order to impart flexibility to the resin film, the resin film is not limited to the above-described plasticizer, and for example, a thermoplastic polyurethane resin, polyvinyl acetate, or the like can be used.

2. Chlorinated polyethylene The chlorinated polyethylene of the present invention is a polyethylene as a raw material, which is obtained by homopolymerization of ethylene or ethylene and 3
Those obtained by copolymerizing an α-olefin having 12 or less (preferably 3 to 9) carbon atoms of 0% by weight or less (preferably 20% by weight or less) are preferable.

Specific examples of the α-olefin include propylene, 1-butene, 1-hexene, 4-methyl-1-pentene and the like. As the polyolefin as a raw material, particularly, one obtained by homopolymerizing ethylene is preferable. The chlorinated polyethylene used in the present invention employs a method of chlorinating polyethylene powder or particles in an aqueous suspension or chlorinating polyethylene dissolved in an organic solvent.

The amount of the chlorinated polyethylene to be added to the vinyl chloride resin is 0.5 to 20 parts by weight, preferably 0.1 to 20 parts by weight.
5 to 10 parts by weight is preferred. If it is less than 0.5, the initial properties and post-weathering properties are not improved, and if it is too large, the film becomes cloudy, which is not preferable. Particularly within the above range, 1.
0 to 7 parts by weight is preferred. The chlorine content of the chlorinated polyethylene must be in the range of 15 to 50% by weight. If the amount is less than 15% by weight, the compatibility with the vinyl chloride resin is inferior and the film becomes cloudy, which is not preferable. If the amount is more than 50% by weight, the physical properties at low temperatures are not improved. Even within the above range, particularly 30 to 45
% By weight is preferred.

[0015] The melt index of the chlorinated polyethylene must be in the range of 0.5 to 150 g / 10 minutes. If it is less than 0.5 g / 10 min, the compatibility with the vinyl chloride resin is inferior and the film becomes cloudy, and if it is more than 150 g / 10 min, the physical properties are not improved in proportion to the added amount, which is not preferable. Even within the above range, especially 1.0 to
130 g / 10 min is preferred. The crystallinity of the chlorinated polyethylene must be between 0 and 30%. In the range higher than 30%, the compatibility with the vinyl chloride resin is poor,
It is not preferable because it bleeds on the film surface. Even within the above range, 20% or less is particularly preferable.

3. Ultraviolet absorber In the present invention, “substantially blocking the transmission of ultraviolet light having a wavelength of 380 nm or less” means not only the case where 100% of the light having the wavelength is completely blocked, but also the light having the wavelength of 2% or less. Use in an acceptable sense. The blending amount of the ultraviolet absorber in the vinyl chloride resin varies depending on the ultraviolet absorption performance and the film thickness of the ultraviolet absorber used, but as a total amount of the ultraviolet absorber with respect to 100 parts by weight of the vinyl chloride resin. It can be in the range of 1.0 to 5 parts by weight. As the ultraviolet absorber in the present invention, those generally used for agricultural vinyl chloride films may be used alone or in combination of two or more. For example, benzotriazole, benzophenone, salicylate, hydroquinone, cyano Various ultraviolet absorbers such as acrylates are exemplified. For example, JP-B-62-38143, column 7, line 27 to column 9, line 34;
No. 53543, column 7, lines 13 to 36, and particularly preferred are benzotriazole-based ultraviolet absorbers and benzophenone-based ultraviolet absorbers. Specifically, the following are mentioned.

2- (2'-hydroxyphenyl) benzotriazole, 2- (2'-hydroxy-5'-methylphenyl) benzotriazole, 2- (2'-hydroxy-5), which are benzotriazole type ultraviolet absorbers
-Methylphenyl) -5-carboxylic acid butyl ester benzotriazole, 2- (2'-hydroxy-5'-methylphenyl) -5,6-dichlorobenzotriazole, 2- (2'-hydroxy-5'-methyl Phenyl)
-5-ethylsulfonebenzotriazole, 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'-dimethyl Phenyl) -5-methoxybenzotriazole, 2- (2′-methyl-4′-
Hydroxyphenyl) benzotriazole, 2- (2 ′
-Stearyloxy-3 ', 5'-dimethylphenyl)
-5-methylbenzotriazole, 2- (2'-hydroxy-5-carboxylic acid phenyl) 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-carboxylate benzotriazole, 2- (2′-acetoxy-5′-methylphenyl) benzotriazole and the like.

A benzophenone-based ultraviolet absorber, 2
-Hydroxy-4-methoxybenzophenone, 2,4-
Dihydroxybenzophenone, 2-hydroxy-4-n
-Octoxybenzophenone, 2-hydroxy-4-methoxy-2'-carboxybenzophenone, 2,2'-
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'-dihydroxy-4,4'-
Dimethoxybenzophenone, 2-hydroxy-5-chlorobenzophenone, bis- (2-methoxy-4-hydroxy-5-benzoylphenyl) methane and the like.

Of course, in addition to the above, known resin additives which are usually blended with the synthetic resin for molding, such as antifogging agents, antifogging agents, lubricants, etc. ,
Formulated with various additives such as heat stabilizers, ultraviolet absorbers, light stabilizers, metal organic phosphates, inorganic substances, antioxidants, stabilizing aids, antistatic agents, fungicides, anti-algal agents and coloring agents can do.

Other examples include an epoxy plasticizer and an organic phosphate. As an epoxy plasticizer,
There are epoxidized vegetable oils such as epoxidized soybean oil and epoxidized linseed oil and epoxy resins. These epoxy plasticizers are added in an amount of 0.1 to 100 parts by weight of the resin.
The amount is from 0.01 to 10 parts by weight, preferably from 0.1 to 5 parts by weight. The compounding amount of the organic phosphate plasticizer is
An appropriate amount is in the range of 1 to 10 parts by weight, particularly 2 to 8 parts by weight, based on 100 parts by weight of the vinyl chloride resin.

As the antifogging agent, nonionic surfactants are preferable, and ether-type ones such as polyoxyethylene ether, polyoxyethylene alkylaryl ether and polyoxyethylene polyoxypropylene ether, and polyhydric alcohols And ester type such as polyoxyethylene ether of glycerin ester and polyoxyl ethylene ether of sorbitan ester. Hereinafter, suitable nonionic surfactants will be exemplified.

(A) Partial ester of a polyhydric alcohol such as sorbitan, sorbitol, mannitol, mannitol, glycerin, diglycerin and a fatty acid having 12 to 22 carbon atoms. (B) The alkylene oxide is ethylene oxide or propylene oxide. The addition mole number is 1 to 20 mol, and the polyhydric alcohol is sorbitan, sorbitol, mannitol, mannitol, glycerin, diglycerin,
Fatty acid esters of polyoxyalkylene polyhydric alcohols in which the fatty acid has 12 to 22 carbon atoms (c) A mixture of (a) and (b).

These mixtures are obtained as mixtures of monoesters, diesters and triesters of polyhydric alcohols. Generally, an ester mixture having a high content of the diester component is preferred. The blending amount of the nonionic surfactant is selected from the range of 0.5 to 5 parts by weight based on 100 parts by weight of the vinyl chloride resin. In particular, 1.0 to 3.0 parts by weight is appropriate.

Examples of the antifog include fluorine-based surfactants. Specifically, the C of the hydrophobic group of a normal surfactant
Is a surfactant in which part or all of H bonded to is substituted with F, particularly a surfactant containing a perfluoroalkyl group or a perfluoroalkenyl group. The blending amount of the fluorine-based surfactant is 1 vinyl chloride resin.
0.01 parts by weight or more and 0.5 parts by weight or less per 100 parts by weight is sufficient, and the preferable range of the compounding amount is 0.02 to 0.1 part by weight.
2 parts by weight.

It is preferable that the vinyl chloride resin film composition according to the present invention contains a specific tackifier. . As the antiadhesive, for example, a melting point of 140 to 146
With methylene bis-stearamide at a melting point of 156 to 16.
0 ° C. ethylenebislauramide, melting point 116-12
N, N′-dioleyl adipamide at 0 ° C., mp 143
Examples thereof include N, N'-distearyl adipamide at a temperature of up to 144 [deg.] C., and particularly preferably a mixture of methylene bis-stearamide and one or more selected from the other three. The compounding amount is preferably in the range of 0.05 to 2 parts by weight based on 100 parts by weight of the vinyl chloride resin, that is, the total amount of methylene bisstearamide and the specific antiblocking agent. When the total amount is less than this range, the winding and lowering workability does not become sufficiently excellent, and when the total amount is large, the added material is blown out after forming into a film, or the antifogging property is hindered. This is undesirable. Of the above ranges, a range of 0.05 to 1.0 part by weight is particularly preferred. Furthermore, preferably, 0.1-1.
The range is 0 parts by weight. As a lubricant or heat stabilizer,
Generally used for agricultural film, fatty acid-based lubricant,
Fatty acid amide lubricants, ester lubricants, polyethylene wax, liquid paraffin, chelators such as organic phosphite compounds, phenols, β-diketone compounds and the like. As the β-diketone compound, dibenzoylmethane, methoxybenzoylbenzoylmethane, chlorobenzoylbenzoylmethane, palmitylbenzoylmethane and the like are preferable. The blending amounts of these lubricants and heat stabilizers are in the range of 0.01 to 2.0 parts by weight,
4 to 1.0 part by weight is preferred.

As the light stabilizer, there can be used various compounds which are usually compounded in agricultural films. For example, hindered amine compounds can be used. Specifically, JP-A-6-155680, No. 5 To 19 pages. These light stabilizers may be used alone or in combination of two or more. The amount is
0.05 to 5.0 per 100 parts by weight of vinyl chloride resin
The range of parts by weight, particularly 0.1 to 2 parts by weight, is preferred.

As the metal salt of organic phosphate, salts of zinc, calcium, barium, magnesium, cobalt or strontium with various organic phosphoric acids are used. Specifically, JP-A-2-30529, page 9, line 9 to line 11
The organic phosphoric acid metal salts described on the last line of the page can be mentioned. These metal organic phosphates may be used alone or in combination of two or more. The compounding amount is in the range of 0.05 to 5.0 parts by weight, particularly preferably 0.1 to 2 parts by weight, per 100 parts by weight of the vinyl chloride resin.

In the present invention, an inorganic substance that absorbs in the infrared region can be blended for the purpose of improving heat retention. Specifically, the following are mentioned. Magnesium carbonate,
Magnesium silicate (talc), silicon oxide, aluminum oxide, barium sulfate, calcium sulfate, magnesium hydroxide, aluminum hydroxide, aluminum hydroxide, calcium hydroxide, metal phosphate, hydrotalcites represented by the following formula (Water-containing or anhydrous-aluminum /
Magnesium / basic carbonate); aluminum / zinc basic carbonate lithium carbonate / aluminum hydroxide inclusion compound, among which aluminum hydroxide, magnesium hydroxide, silicon oxide, magnesium carbonate, and hydrotalcite Are particularly preferred because they do not reduce the transparency of the film. (I): M ²⁺ _(1-X) Al ³⁺ _X (OH ⁻ ) _2. (A ₁ ⁿ⁻ ) _{x / n.}
mH in ₂ O (wherein, M ²⁺ represents a divalent metal ion, A ^n-n-valent anion, respectively, x, m and n, 0 <x <
0.5, 0 ≦ m ≦ 2, 1 ≦ n ≦ 3, respectively. ) (II): Li ⁺ (Al ³⁺ ) ₂ (OH ⁻ ) _6. (A ₂ ^{n −} ) _{1 / n.}
mH ₂ O (wherein, A ^n- represents an anion of n valence, respectively, and m
And n satisfy the conditions of 0 ≦ m ≦ 3 and 1 ≦ n ≦ 3, respectively. (III): [(Li ⁺ _(1-X) M ²⁺ _X ) (Al ³⁺ ) ₂ (OH ⁻ )
₆ ] ₂ (Si _y O _{(2y + 1)} ^2- ) _{(1 + x)} · mH ₂ O (wherein M ²⁺ represents a divalent metal ion, and m, x and y are 0 ≦ m <5, 0 ≦ x <1, 2 ≦ y ≦ 4 are satisfied.) (IV): [(Li ⁺ _(1-X) M ²⁺ _X ) (Al ³⁺ ) ₂ (O
_{^{H -) 6] 2 (A}} 3 n-) 2 ( in _{1 + x) / n · mH} 2 O ( wherein, M ²⁺ is a divalent metal ion, A ^n-n-valent anion represents respectively , M, x and n are 0 ≦ m <
5, the conditions of 0.01 ≦ x <1, 1 ≦ n ≦ 3 are respectively satisfied. (V): mAl ₂ O ₃ · (n / p) M _{2 / p} O · X · kH ₂ O (where X represents a carbonate group, M represents an alkali metal or an alkaline earth metal, and p represents The valence of the metal M, where m, n and k are 0.3 ≦ m ≦ 1, 0.3 ≦ n ≦
2. The condition of 0.5 ≦ k ≦ 4 is satisfied. One or more of these inorganic substances can be added, and the compounding amount thereof is in the range of 0.5 to 10 parts by weight, particularly in the range of 2 to 10 parts by weight per 100 parts by weight of the vinyl chloride resin. preferable.

As the compound which can be used as an antioxidant, phenolic and sulfuric antioxidants can be used, and specifically, 2,6-di-butyl-4-methylphenol-
2,2'-methylenebis (6-tert-butyl-4-
Ethylphenol), dilaurylthiodipropionate and the like. These antioxidants can be used alone or in combination of two or more.

Compounds that can be used as a stabilizing aid include triphenyl phosphite, dioctyl phenyl phosphite, tris (nonylphenyl) phosphite, diphenyl indecyl phosphite, trilauryl trithio phosphite, diphenyl acid phosphite and the like. Can be given. These stabilizing aids can be used alone or in combination of two or more.

Examples of the antistatic agent include polyoxyethylene alkylamine, polyglycol ether, p-
And sodium styrenesulfonate. As the fungicide and the anti-algal agent, various compounds generally used in agricultural vinyl chloride films can be used.
Examples thereof include organic nitrogen compounds, and specific examples thereof include imidazole derivatives, anilide derivatives, urea derivatives, ammonium derivatives, triazine derivatives, and phthalimide derivatives. Examples of usable coloring agents include phthalocyanine blue, phthalocyanine green,
Hansa Yellow, Alizarin Lake, titanium oxide, zinc white, permanent red, quinacridone, carbon black and the like can be mentioned. These colorants can be used alone or in combination of two or more.

The above various resin additives can be selected in a range that does not deteriorate the properties of the film, usually in a range of 5 parts by weight or less based on 100 parts by weight of the vinyl chloride resin.
To blend the resin additives into the vinyl chloride resin, weigh each required amount, and use a ribbon blender, Banbury mixer,
What is necessary is just to use a super mixer and other conventionally known compounding machines and mixers.

In order to form a film of the resin composition thus obtained, a method known per se, for example, a melt extrusion molding method (including a T-die method and an inflation method),
A known method such as a calendering method or a solution casting method may be used. The thickness of the film is 0.03-
0.3 mm range, preferably 0.05-0.2 mm
It is preferable to set it in the range. If it is thinner than 0.03 mm,
The film is not strong enough to break easily, 0.3m
If the thickness is larger than m, the operations such as cutting and bonding are adversely affected. The agricultural resin film of the present invention may have a lattice shape, a stripe shape, or a fine uneven pattern (texture pattern) on at least one surface of the surface of the base film.

In order to further improve the durability and dust resistance, it is preferable to form an acrylic resin film on one surface of the agricultural vinyl chloride resin film according to the present invention. As the acrylic resin to be used, hydroxyalkyl (meth) acrylate is 5 to 40% by weight,
A polymer obtained by copolymerizing 0 to 20% by weight of an α, β-unsaturated carboxylic acid containing one or more carboxyl groups and another vinyl monomer copolymerizable therewith is preferred.

Examples of the hydroxyalkyl (meth) acrylate include hydroxymethyl acrylate, hydroxymethyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate, 2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, 3-hydroxypropyl acrylate, 3-hydroxypropyl methacrylate, 2-hydroxybutyl acrylate, 2-hydroxybutyl methacrylate, 4-hydroxybutyl acrylate, 4-
Examples thereof include hydroxybutyl methacrylate, 2-hydroxypentyl acrylate, 2-hydroxypentyl methacrylate, 6-hydroxyhexyl acrylate, and 6-hydroxyhexyl methacrylate.

These hydroxyalkyl (meth) acrylate compounds make it easy for the resulting acrylic resin to be dissolved in an organic solvent, improve the adhesion between the acrylic resin and the base vinyl chloride resin film, and further improve the stain on the film surface. It is a component that greatly contributes to the action of suppressing the migration of the plasticizer that comes out. The ratio of the hydroxyalkyl (meth) acrylate in the acrylic resin is 5% by weight.
When the amount is less than the above, the effect of improving the solubility with the organic solvent, the adhesion to the base film and the durability cannot be sufficiently exhibited. On the other hand, when the amount is more than 40% by weight, the cost becomes high and the cost increases. The effect obtained is not great and is not preferred.

The α, β-unsaturated carboxylic acid having one or more carboxyl groups in the molecule includes acrylic acid, methacrylic acid, itaconic acid, maleic acid, maleic anhydride, aconitic acid, fumaric acid, Crotonic acid, itaconic acid and the like. When these compounds are used in combination with the hydroxyalkyl (meth) acrylate, the adhesion and durability between the acrylic resin and the base film are improved. The use amount of these is preferably 0.5 to 20% by weight. If it is more than this, the property that the films adhere to each other when the film is moistened with moisture (the blocking property when wet) is undesirably enhanced.

Other vinyl monomers copolymerizable with the hydroxyalkyl (meth) acrylate and the α, β-unsaturated carboxylic acid include alkyl (meth) acrylate or a mixture thereof with alkenylbenzene. Is raised. Examples of the alkyl (meth) acrylate include methyl acrylate, ethyl acrylate, n-propyl acrylate, isopropyl acrylate, n-butyl acrylate, 2-ethylhexyl acrylate, and the like. Decyl acrylate, methyl methacrylate, ethyl methacrylate, methacrylic acid
Examples thereof include n-propyl ester, isopropyl methacrylate, n-butyl methacrylate, 2-ethylhexyl methacrylate, and decyl methacrylate, and are generally acrylic having 1 to 20 carbon atoms in the alkyl group. Acid alkyl esters and / or alkyl esters of methacrylic acid having 1 to 20 carbon atoms in the alkyl group are used.

The alkenylbenzene used in the present invention includes, for example, styrene, α-methylstyrene, vinyltoluene and the like. When a monomer comprising a mixture of such an alkenylbenzene and an alkyl (meth) acrylate is used, it usually varies depending on the amount of the α, β-ethylenically unsaturated carboxylic acid to be used. Use ratio of alkyl acrylate of 10
% By weight or more.

In particular, the acrylic resin of the present invention comprises a monomer comprising a mixture of the above-mentioned alkyl (meth) acrylate and a mixture thereof with alkenylbenzene in an amount of from 40 to 60.
What contains by weight is preferable. When such an acrylic resin is subjected to a surface treatment on a base vinyl chloride resin film, another resin compatible with the acrylic resin can be mixed for the purpose of improving the adhesion to the film. As the other resin, a vinylidene fluoride resin, an acrylic resin having a perfluoroalkyl group in a side chain, a cellulose acetate butyrate resin, a silicone resin, and the like are particularly effective.

In order to polymerize the acrylic resin, a predetermined amount of each monomer is combined, charged together with an organic solvent into a polymerization vessel, a polymerization initiator and, if necessary, a molecular weight regulator are added, and the mixture is heated with stirring. Good.

The acrylic resin film formed on one side of the vinyl chloride resin film is preferably applied by dissolving the acrylic resin in the above-mentioned organic solvent. To form a coating of the acrylic resin on the surface of the vinyl chloride resin film, the acrylic resin is dissolved in an organic solvent, and spray coating, roll coating, gravure coating, reverse coating, and dip coating are performed. In addition to the above, it is preferable to apply and dry by various known coating methods such as a screen printing method and a flexographic printing method. Available drying methods include, for example, hot air drying, infrared drying, far infrared drying and the like. The drying temperature is preferably a temperature at which the organic solvent is scattered, that is, the boiling point of the organic solvent in which the acrylic resin is dissolved. The shorter the drying time, the better. Therefore, it is preferable to dry at a temperature equal to or higher than the boiling point of the organic solvent in the shortest possible time.

The thickness of the acrylic resin film formed on the surface of the base film depends on the thickness of the base film.
Select from the range of 0.5 to 10 μm. When the thickness is more than 10 μm, since there is a difference in flexibility between the base film and the coating, phenomena such as peeling of the coating from the base film are likely to occur, and the coating is cracked to lower the strength of the base film. This phenomenon is undesirable. 0.5
When the thickness is smaller than μm, the effect of improving the durability and dustproofness of the base film is not exhibited, so that it is not preferable. The thickness of the coating is preferably proportional to the thickness of the base film within the above range.

In actual use of the agricultural polyvinyl chloride resin film according to the present invention, when the coating is formed on only one side, the side on which the coating is provided is outside the house or tunnel. It is good to expand in this way.

[0045]

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited to the following examples unless it exceeds the gist. Examples 1 to 3 and Comparative Examples 1 to 4 (1) Production of vinyl chloride resin film Polyvinyl chloride (degree of polymerization = 1300) 100 parts by weight Di-2-ethylhexyl phthalate 45 parts by weight Tricresyl phosphate 5 parts by weight Epoxy Resin (trade name "EP-828") 1.5 parts by weight Ba-Zn liquid stabilizer 1 part by weight Barium stearate 0.2 parts by weight Zinc stearate 0.4 parts by weight Sorbitan monopalmitate 1.5 parts by weight β-diketone compound (dibenzoylmethane) 0.1 part by weight Fluorinated surfactant (trade name “Unidyne DS-401”) 0.2 part by weight The above-mentioned resin raw materials and resin additives are weighed and further added thereto. The composition shown in Table 1, the chlorinated polyethylene in parts by weight shown in Table 2, the ultraviolet absorber, and the inorganic particles, the types and amounts shown in Table 2 to prevent adhesion It was formulated. After stirring and mixing these with a super mixer for 10 minutes, 165
The mixture was kneaded on a roll heated to 0 ° C., and a transparent vinyl chloride resin film having a thickness of 0.10 mm was produced using an L-type calender.

(2) Formation of Coating Film 150 parts by weight of isopropyl alcohol and 2 parts
-20 parts by weight of hydroxyethyl methacrylate, 10 parts by weight of acrylic acid, 40 parts by weight of methyl methacrylate and 30 parts by weight of ethyl methacrylate, 0.5 part by weight of benzoyl peroxide, and 8 parts by weight under a nitrogen gas stream.
The polymerization reaction was performed at 0 ° C. for 10 hours. Isopropyl alcohol was added to the obtained copolymer solution to reduce the solid content to 2%.
It was adjusted to 0% by weight to obtain a coating resin. After coating the coating resin on one side of the base film produced in the above (1) by a gravure coating method, the coating resin is retained for 10 seconds in a hot-air drying oven controlled at a temperature of 150 ° C. to disperse the solvent. A coating of about 2 μm was formed.

Evaluation of Film The performance of the film was evaluated by the following method, and the results are shown in Table 3. (3) Initial appearance The appearance of the films prepared in Examples and Comparative Examples was observed with the naked eye, and the straight light transmittance (wavelength: 555 nm) was measured with an EPS-2U model manufactured by Hitachi, Ltd. The evaluation criteria are as follows. (3-1) Visual appearance A: Surface roughness is not uneven, rough and wrinkle-free. Δ: Uneven or rough and wrinkle-free surface gloss. X: Irregular, rough and wrinkled surface gloss. (3-2) Straight ray transmittance ◎: The transmittance is 85% or more. …: Transmittance of 65% to 84%. Δ: transmittance of 45% to 64%. ×: transmittance is less than 45%.

(3) Room temperature physical properties Tensile properties: The films obtained in Examples and Comparative Examples were subjected to JI
According to SK6732, the elongation at break was measured in a room at 23 ° C.

(4) Low-temperature physical properties Impact strength: Nine samples of 10 cm × 10 cm films were prepared, and the thickness of the center of the sample was measured with a dial gauge specified in JIS B-7503. The above samples were measured in a room at -15 ° C with a puncture manufactured by Toyo Seiki Co., Ltd. The degree of impact is represented by the following equation. Impact strength = measured value (impact value) / measured thickness × nominal thickness (5) Ejection property The condition of the film surface left standing for 7 months in a thermo-hygrostat at a temperature of 40 ° C. and a relative humidity of 80% was visually observed. The evaluation criteria are as follows. ◎ ・ ・ ・ The film is almost completely transparent.・ ・ ・: A little white and powdery spouting, but almost transparent. ○ × ・ ・ There is a white powdery spout, and transparency is slightly impaired. Δ: White powdery squirt was observed, the film was in a satin shape, and the transparency was poor. ×: White powdery spouting is remarkable and opaque.

(6) Stickiness The film cut to a width of 30 cm and a length of 150 cm was immersed in tap water of Nagoya City for 7 days, and wound around a galvanized iron pipe having a diameter of 2 cm and a width of 35 cm.
It was left in an oven at 55 ° C. for 4 weeks and dried. The ease of peeling when the film was unwound from the iron pipe was evaluated according to the following criteria.・ ・ ・: Smooth peeling and no resistance.・ ・ ・: There is a little resistance at the beginning of peeling. Δ: There is resistance to peeling. ×: Not easily peeled off, with great force.

(7) Antifogging property, impact strength after outdoor exposure The film was coated on a pipe house (3 m wide, 10 m deep, 1.5 m high) at a test field in Isshi-gun, Mie Prefecture, November 1998. A one-year expansion test was performed from -1999 to November 1999. The stretched film was evaluated for the anti-fogging property at the initial stage of the spreading (after 1 hour of the spreading), the long-term anti-fogging property, and the impact strength in a room at 0 ° C. by the following methods. (7-1) Antifog properties at the initial stage of spreading A: Water droplets are uniformly wet in a streak shape and are transparent.・ ・ ・: Water droplets began to flow in a streak shape and were considerably transparent. ○ × ・ ・ Water droplets grew and there was no white shining part, and the whole was transparent. Δ: Fine water droplets adhered, but partly transparent. ×: Fine water droplets adhere to the entire surface and appear to glow white. (7-2) Extended long-term anti-fog properties ・ ・ ・: Uniformly wet on one side and completely transparent water film.・ ・ ・: Wet almost uniformly, water film almost transparent. ○ × ・ ・ Partially opaque with water droplets attached. Δ: Many water droplets adhered and many opaque parts. ×: Fine water droplets adhered to the entire surface, making it opaque.

[0052]

[Table 1]

[0053]

[Table 2]

[0054]

[Table 3]

[0055]

(1) The vinyl chloride resin film for agriculture of the present invention is excellent in physical properties at low temperatures even when a large amount of an ultraviolet absorber is added, and is torn when stretched and exposed outdoors. It has excellent resistance to tearing due to external forces after expansion (wind, snow, hail, arare, etc.) due to its excellent impact strength afterward. (2) The vinyl chloride resin film for agriculture of the present invention is further excellent in stickiness, initial expansion and long-term anti-fog properties. It can also be used for parts such as sides, skylights, doorways, wives, etc., and is extremely valuable as an agricultural covering.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08K 5/00 C08K 5/00 5/3475 5/3475 // (C08L 27/06 (C08L 27/06 23 : 28) 23:28) (72) Inventor Takeshi Ken Tashiro 2 Oike, Iwatsukacho, Nakamura-ku, Nagoya-shi, Aichi Prefecture Mitsubishi Chemical MKV Corporation Nagoya Office (72) Inventor Isamu Takagi 2 Oiketsu, Iwatsukacho, Nakamura-ku, Nagoya-shi, Aichi Prefecture Address Mitsubishi Chemical MKV Co., Ltd. Nagoya Office F-term (reference) 2B024 DB01 EA01 2B029 EC04 EC09 EC14 EC16 EC19 4F006 AA17 AB24 BA03 BA10 CA06 DA04 4F071 AA15 AA24 AA79 AC12 AE04 AE05 AH01 BC01 4J05 EB242B031 EH146 EU177 FD026 FD040 FD057 FD070 FD100 GA01

Claims (4)

[Claims] 1. 0.5 to 20 parts by weight of chlorinated polyethylene, 100 parts by weight of a vinyl chloride resin and 3 parts of a plasticizer
0 to 60 parts by weight of a vinyl chloride resin film for agricultural use, comprising an ultraviolet absorber in an amount that substantially prevents transmission of ultraviolet light having a wavelength of 380 nm or less. 2. The chlorinated polyethylene having a chlorine content of 15
~ 50% by weight, melt index 0.5 ~ 150g /
2. A vinyl chloride resin film for agricultural use according to claim 1, wherein the crystallinity is 0 to 30% for 10 minutes. 3. The ultraviolet absorber is a benzotriazole derivative having a chlorine group, and is blended in an amount of 0.5 to 5 parts by weight with respect to 100 parts by weight of a vinyl chloride resin. A vinyl chloride resin film for agriculture according to the above item. 4. The agricultural vinyl chloride resin film according to claim 1, wherein an acrylic resin film is formed on one or both surfaces of the vinyl chloride resin film.