JP2003327767A - Agricultural vinyl chloride resin film - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an agricultural film excellent not only in tear strength and tensile elongation but also in physical properties (strength and impact resistance) at a low temperature, visual appearance and light transmittance. <P>SOLUTION: The vinyl chloride resin film for agriculture is obtained by blending 40-60 pts.wt. of a plasticizer with 100 pts.wt. of a vinyl chloride resin which has an average degree of polymerization of 1,750 to 1,850 and has a relational expression of 1.9≤Mw/Mn≤2.3 between the weight-average molecular weight (Mw) and the number-average molecular weight (Mn). The film with a thickness of 0.1 mm has: (a) impact strength at -15°C of 0.5 J or higher; (b) Elmendorf tear strength at 23°C of 7.5 N or higher; and (c) tensile elongation at break of 300% or greater. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a vinyl chloride resin film for agriculture. More specifically, the present invention relates to a vinyl chloride resin film for agriculture, which has excellent tear strength and tensile elongation, strength and impact resistance at low temperatures, and visual appearance and light transmittance.

[0002]

2. Description of the Related Art In recent years, vinyl chloride resin films have been used as agricultural films for covering greenhouses or tunnels for efficiently cultivating useful plants because of their excellent weather resistance, transparency and heat retention. It is used a lot.

However, the soft vinyl chloride resin film contains a plasticizer as a resin softening agent,
This plasticizer has a large temperature sensitivity, and is poorly stretched and easily broken particularly when it is used for spreading in cold regions. Further, there is a problem that even after the stretching, the film is easily torn when an external force such as wind, snow, hail, and arale is applied to the film. Therefore, as a method of improving physical properties such as impact resistance in cold regions, the amount of plasticizer in the vinyl chloride resin film for agriculture as described below is increased, or plasticization such as blending of a cold resistant plasticizer is performed. A method for compounding agents has been proposed.

However, it is known that the method of increasing the amount of the plasticizer in the vinyl chloride resin film has an improving effect on the low temperature strength, but in this method, the film is formed at high temperature such as in summer. , Known to be sticky and slack. 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-58-497).
42, etc.). However, this method generally has poor compatibility with vinyl chloride resins, and has the drawback of bleeding and poor heat resistance. Further, there is a defect that weather resistance is poor (browning, etc.). On the other hand, as the vinyl chloride resin used for agricultural vinyl chloride resin films, those having an average degree of polymerization of about 1100 to 1300 have been conventionally used. Use of an agricultural vinyl chloride resin film in which 100 parts by weight of a vinyl resin is mixed with inactive solid fine particles having a specific particle diameter (Japanese Patent Laid-Open No. 62-177050) and a polymerization degree of 1
Vinyl chloride resin A of 100 or more and 1500 or less and vinyl chloride resin B of 500 or more and less than 1100
And the average degree of polymerization of the mixture is 1000 to 160.
0 vinyl chloride resin is used (Japanese Patent Publication No. 5-8217).
No. 4, etc.) have also been proposed, but since a material having a specific Mw / Mn ratio is not used, a vinyl chloride resin film for agriculture in which transparency and strength are well balanced is obtained. There wasn't.

[0005]

Under the circumstances, the inventors of the present invention have excellent tear strength and tensile elongation, and have excellent physical properties (strength and impact resistance) at low temperature, visual appearance and light transmittance. Another object of the present invention is to provide a vinyl chloride resin film for agriculture which is excellent in

[0006]

However, the gist of the present invention is that the average degree of polymerization is 1750 or more and 1850 or less, the weight average molecular weight (hereinafter referred to as "Mw") and the number average molecular weight (hereinafter referred to as "Mn"). The vinyl chloride resin film for agricultural use, characterized in that 40 parts by weight or more and 60 parts by weight or less of a plasticizer is mixed with 100 parts by weight of the vinyl chloride resin having the following relationship. Exist in. 1.9 ≦ Mw / Mn ≦ 2.3

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below.
In the present invention, the vinyl chloride resin means 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 emulsion polymerization method, suspension polymerization method, solution polymerization method and bulk polymerization method.

In the present invention, the average degree of polymerization is 1750.
It is characterized in that a vinyl chloride resin having a Mw / Mn of 1.9 or more and 1.9 or more and 2.3 or less is used. Preferably, the Mw / Mn is 1.95 or more and 2.25 or less. The average degree of polymerization is JIS K-
6721 is the viscosity average degree of polymerization. If the average degree of polymerization is too low, the strength at low temperature according to the present invention is unfavorably lowered, and if the degree of polymerization is too high, the workability is deteriorated, which is not preferable. Particularly, when the average degree of polymerization is in the range of 1750 or more and 1850 or less, the tear strength at room temperature and the impact strength at low temperature are significantly improved, which is preferable. Mw is a weight average molecular weight and Mn is a number average molecular weight, and both can be measured by a gel permeation chromatography method or the like. The Mw / Mn of a known vinyl chloride resin is usually distributed in the range of about 1 to 5, but in the present invention, the Mw within a limited specific range.
By using a vinyl chloride resin having / Mn,
It is possible to obtain an agricultural film having good light transmittance.

In order to impart flexibility, the vinyl chloride resin film as the above-mentioned substrate has 40 parts by weight or more and 60 parts by weight or less, preferably 40 parts by weight or more and 55 parts by weight, relative to 100 parts by weight of the resin. It is compounded below. If the amount is less than 40 parts by weight, the flexibility at low temperature is poor and sufficient low temperature physical properties cannot be obtained. Also, if it exceeds 60 parts by weight,
The handleability at room temperature (stickiness etc.) deteriorates,
This is not preferable because the workability at the time of film forming processing is reduced.

Examples of plasticizers that can be used include 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 maleate; 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; In addition, epoxidized large oil, epoxy resin-based plasticizer, etc. may be mentioned. Further, in order to impart flexibility to the resin film, it is not limited to the above-mentioned plasticizer, and for example, thermoplastic polyurethane resin, polyvinyl acetate, etc. can be used.

The agricultural vinyl chloride resin film of the present invention preferably contains a β-diketone compound from the viewpoint of preventing discoloration due to heat during processing. The β-diketone compound may be any that is usually blended in an agricultural vinyl chloride film, and examples thereof include dibenzoylmethane, methoxybenzoyl benzoylmethane, chlorobenzoyl benzoylmethane, palmityl benzoyl methane, and dehydroacetic acid. . As the β-diketone compound,
A compound containing one or more structural units represented by the following general formula (I) in one molecule is suitable.

[0012]

[Chemical formula 1] (I)

(In the formula (I), R1 and R2 have 1 carbon atoms.
4 represents an alkyl group or a phenyl group. Examples of the compounds contained in the general formula (I) include acetylacetone, benzoylacetone, benzoylpropionylmethane, dibenzoylmethane and the like. If the blending amount of the β-diketone compound into the vinyl chloride resin film is too small, discoloration due to heat during molding occurs, which is not preferable, and even if it is too large, the coloring resistance of the film is proportional to the addition amount. And there is no improvement. The preferable amount of addition is 0.00 with respect to 100 parts by weight of the vinyl chloride resin.
It is in the range of 5 to 0.10 parts by weight.

From the viewpoint of improving impact strength, it is preferable to add an impact resistance improver to the agricultural vinyl chloride resin film of the present invention. As the impact resistance improver, it is preferable to mix chlorinated polyethylene, methyl methacrylate-butadiene-styrene (hereinafter referred to as MBS) resin, and acrylic elastomer particles selected from the particles. The amount of the impact modifier added to the vinyl chloride resin film is
If the amount is too large or too small, the impact resistance improving effect cannot be obtained. The preferable blending amount is in the range of 1 to 10 parts by weight with respect to 100 parts by weight of the vinyl chloride resin.

The chlorinated polyethylene is a polyethylene as a raw material, which is homopolymerized with ethylene or has a carbon number of not more than 30% by weight (preferably not more than 20% by weight) with ethylene and not more than 12 (preferably 3 to 10). (9) α-olefin.

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

MBS (methyl methacrylate-butadiene-styrene) resin is a graft polymer of polybutadiene latex. Mention may be made, for example, of core-shell polymer particles comprising a rubbery polymer core based on polybutadiene and a rigid polymer shell derived from methylmethacrylate units. The refractive index of MBS is 1.4
It is preferably 0 to 1.60, and more preferably
It is 1.45 to 1.55. The refractive index is measured by a dipping method (in a 23 ° C. room, using D line).

The acrylic elastic particles are obtained by a sequential multi-stage polymerization method in which an alkyl methacrylate monomer is a main component and an alkyl methacrylate monomer and another vinyl monomer copolymerizable with the alkyl methacrylate monomer are used. It is a polymer having a multilayer structure. As the multilayer structure polymer, a three-stage polymer (three-layer structure) or a four-stage polymer (four-layer structure) is preferable.

The alkyl methacrylate monomer is preferably an alkyl methacrylate monomer having an alkyl group having 8 or less carbon atoms. Specific examples thereof include methyl methacrylate, ethyl methacrylate, n-propyl methacrylate, i-propyl methacrylate, n-butyl methacrylate, i-butyl methacrylate, cyclohexyl methacrylate and 2-ethylhexyl methacrylate.

Other monomers copolymerizable with alkyl methacrylate include ethyl acrylate, n-propyl acrylate, i-propyl acrylate, n-butyl acrylate, i-butyl acrylate, cyclohexyl acrylate, 2-ethylhexyl acrylate and decyl. C1 to C16 of acrylic acid such as acrylate
Alkyl esters of: ethyl methacrylate, n-propyl methacrylate, i-propyl methacrylate,
C1-C16 alkyl esters of methacrylic acid such as n-butyl methacrylate, i-butyl methacrylate, cyclohexyl methacrylate, 2-ethylhexyl methacrylate, and decyl methacrylate: styrene, acrylonitrile, methacrylonitrile and the like. These vinyl monomer monomers copolymerizable with methyl methacrylate may be copolymerized by combining one kind or several kinds.

Acrylic elastic particles are the same as those of the above monomers.
A predetermined amount of at least one kind is combined and charged into a polymerization vessel, a polymerization initiator, an emulsifier, and a graft crossing agent are added if necessary, and the emulsion polymerization is carried out by a usual multistage polymerization method. This sequential multi-stage polymerization method is carried out under such conditions that the monomers continuously added to the aqueous dispersion or emulsion are successively sheet-polymerized on the emulsion particles formed by the previously added monomers. . The polymerization of each layer is carried out after the previous polymerization is completed, followed by dropwise polymerization, coagulation by a normal salting-out method, and drying. The polymerization initiator may be any one usually used in emulsion polymerization, and examples thereof include water-soluble persulfates and redox initiators. As the emulsifier, an anionic surfactant is preferred, but any emulsifier usually used in emulsion polymerization may be used.

Of course, in addition to the above, the vinyl chloride-based resin may also include, if necessary, known resin additives such as an antifogging agent, an antifog agent, and a lubricant, which are usually added to synthetic resins for molding. ,
Various additives such as heat stabilizers, UV absorbers, light stabilizers, organophosphate metal salts, inorganic substances, antioxidants, stabilizing aids, antistatic agents, mildew-proofing agents, algae-proofing agents and coloring agents can do.

Other examples include epoxy plasticizers and organic phosphates. As an epoxy plasticizer,
There are epoxidized vegetable oils such as epoxidized soybean oil and epoxidized linseed oil, and epoxy resins. The addition amount of these epoxy plasticizers is 0.
The amount is 01 to 10 parts by weight, preferably 0.1 to 5 parts by weight.

Examples of the organic phosphate ester-based plasticizer include triisopropylphenyl phosphate, isodecyldiphenyl phosphate, tris (isopropylphenyl)
There are phosphate, tributyl phosphate, triethyl phosphate, trioctyl phosphate, tributoxyethyl phosphate, triphenyl phosphate, octyl diphenyl phosphate, trixylenyl phosphate, etc. Among them, tricresyl phosphate and trixylenyl phosphate are particularly preferable. The blending amount of these plasticizers is appropriately 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, polyoxyethylene polyoxypropylene ether, polyhydric alcohol and the like. Examples thereof include ester type of partial esterified product of fatty acid, polyoxyethylene ether of glycerin ester, and ether ester type of sorbitan ester such as polyoxyl ethylene ether. Examples of suitable nonionic surfactants are shown below.

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

These mixtures are obtained as a mixture of monoesters, diesters and triesters of polyhydric alcohols. Generally, an ester mixture having a composition containing a high proportion of the diester component is suitable. The compounding amount of the nonionic surfactant is selected from the range of 0.5 to 5 parts by weight with respect to 100 parts by weight of the vinyl chloride resin. Particularly, 1.0 to 3.0 parts by weight is suitable.

Examples of the antifogging agent include fluorine-containing surfactants. Specifically, C of the hydrophobic group of ordinary surfactants is used.
A surfactant in which a part or all of H bound 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 vinyl chloride resin 1
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.
2 parts by weight.

The vinyl chloride resin film composition according to the present invention preferably contains a specific anti-adhesive agent.
Examples of the anti-adhesive agent include methylenebisstearamide having a melting point of 140 to 146 ° C., ethylenebislaurylamide having a melting point of 156 to 160 ° C., N, N′-dioleyl adipamide having a melting point of 116 to 120 ° C., and melting point 143. ~ 14
Examples include N, N′-distearyl adipamide at 4 ° C. and the like, but it is particularly preferable to mix a mixture of methylenebisstearoamide 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, the total amount of methylenebisstearamide and the specific anti-sticking agent. If the total amount is less than this range, the workability for winding and unwinding will not be sufficiently excellent, and if the total amount is more than this range, the substances added after film formation will spout or hinder the antifogging property. The problem occurs, which is not preferable. Of the above ranges, the range of 0.05 to 1.0 parts by weight is particularly preferable. Furthermore, it is preferably in the range of 0.1 to 1.0 part by weight.

As the lubricant or heat stabilizer, fatty acid lubricants, fatty acid amide lubricants, ester lubricants, polyethylene wax, liquid paraffin, chelating agents such as organic phosphite compounds, and phenols, which are generally used for agricultural films, are used. And β-diketone compounds. As the β-diketone compound, dibenzoylmethane, methoxybenzoyl · benzoylmethane, chlorobenzoyl · benzoylmethane, palmitylbenzoylmethane and the like are preferable. The blending amount of these lubricants and heat stabilizers is in the range of 0.01 to 2.0 parts by weight, particularly 0.04 to
1.0 part by weight is preferred.

The ultraviolet absorber may be any one which is usually blended in a vinyl chloride film for agriculture, and various kinds of ultraviolet absorbers such as benzotriazole type, benzophenone type, salicylate type, hydroquinone type and cyanoacrylate type may be mentioned. To be For example, Japanese Patent Publication Sho-62-38
No. 143, column 7, line 27 to column 9, line 34; JP-B No. 62-53543, column 7, line 13 to line 36, and particularly a benzotriazole-based ultraviolet absorber. Agents and benzophenone-based UV absorbers are preferred. Specific examples include the following.

2- (2'-hydroxyphenyl) benzotriazole, 2- (2'-hydroxy-5'-methylphenyl) which is a benzotriazole type ultraviolet absorber.
Benzotriazole, 2- (2'-hydroxy-5-methylphenyl) -5-carboxylic acid butyl ester benzotriazole, 2- (2'-hydroxy-5'-methylphenyl) -5,6-dichlorobenzotriazole, 2-
(2'-hydroxy-5'-methylphenyl) -5-ethylsulfone benzotriazole, 2- (2'-hydroxy-5'-t-butylphenyl) -5-chlorobenzotriazole, 2- (2'-hydroxy) -5'-t-butylphenyl) benzotriazole, 2- (2'-hydroxy-5'-aminophenyl) benzotriazole, 2-
(2′-hydroxy-3 ′, 5′-dimethylphenyl) benzotriazole, 2- (2′-hydroxy-3 ′, 5 ′
-Dimethylphenyl) -5-methoxybenzotriazole, 2- (2'-methyl-4'-hydroxyphenyl) benzotriazole, 2- (2'-stearyloxy-
3 ', 5'-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-ethylsulfone benzotriazole, 2- (2'-hydroxy-4'-octoxyphenyl) benzotriazole, 2- (2'-hydroxy-5'-methoxy Phenyl)
-5-methylbenzotriazole, 2- (2'-hydroxy-5'-methylphenyl) -5-carboxylic acid ester benzotriazole, 2- (2'-acetoxy-5'-
Methylphenyl) benzotriazole and the like.

2 which is a benzophenone type ultraviolet absorber
-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, 2,2'-dihydroxy-4,4' -Dimethoxybenzophenone, 2-hydroxy-5-chlorobenzophenone, bis- (2-methoxy-4-hydroxy-
5-benzoylphenyl) methane and the like.

The ultraviolet absorbers may be used alone or in combination of two or more. The blending amount thereof is preferably in the range of 0.01 to 3.0 parts by weight, and particularly preferably 0.02 to 2.0 parts by weight, per 100 parts by weight of the vinyl chloride resin.

As the light stabilizer, various compounds commonly used in agricultural films can be used. Examples thereof include hindered amine compounds, and specifically, JP-A-6-155680, No. 5 can be used. To the compounds described on page 19 and the like. These light stabilizers may be used alone or in combination of two or more. The blending amount is
0.05 to 5.0 per 100 parts by weight of vinyl chloride resin
A range of parts by weight, particularly 0.1 to 2 parts by weight is preferred.

As the organic phosphate metal salt used in the present invention, those represented by the following general formula (II) or (III) are preferable.

[0037]

[Chemical formula 2] (II)

[Chemical Formula 3] (III)

(In the formula, M is zinc, calcium, barium, magnesium or strontium, and R5, R6 and R7 are each an alkyl group having 1 to 22 carbon atoms, an aryl group, an aralkyl group, an alkylaryl group or an ether bond. Examples of the hydrocarbon group containing an alkyl group, an aryl group, an aralkyl group, an alkylaryl group or an ether bond having 1 to 22 carbon atoms in the general formula (II) or (III). Are as follows.

As the alkyl group, a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group,
Isobutyl group, sec-butyl group, tert-butyl group, n-amyl group, neopentyl group, isoamyl group, hexyl group, heptyl group, n-octyl group, isooctyl group, 2-ethylhexyl group, n-nonyl group, isononyl group , Decyl group, lauryl group, tridecyl group, 1-octadecyl group, cyclopentyl group, cyclohexyl group, cyclooctyl group, 4-methylcyclohexyl group and the like.

Examples of the aryl group include a phenyl group and a naphthyl group, and examples of the arylalkyl group include a benzyl group, a β-phenylethyl group and an α-phenylpropyl group. Examples of alkylaryl groups include:
Examples thereof include a tolyl group, a xylyl group, an ethylphenyl group, a butylphenyl group, a tert-butylphenyl group, an octylphenyl group, a nonylphenyl group and a 2,4-di-tert-butylphenyl group.

Examples of the hydrocarbon group containing an ether bond include furfuryl group, tetrahydrofurfuryl group, 5-methylfurfuryl group, α-methylfurfuryl group, methylcellosolve residue (ether obtained by removing the hydroxyl group from the above cellosolve. A hydrocarbon group containing a bond, the same hereinafter), ethyl cellosolve residue, isopropyl cellosolve residue, butyl cellosolve residue, isobutyl cellosolve residue, hexyl cellosolve residue, cyclohexyl cellosolve residue, phenyl cellosolve residue, methylcarbitol Residues (referred to as hydrocarbons containing an ether bond in which the hydroxyl group is removed from carbitol, the same applies hereinafter), ethyl carbitol residues, isopropyl carbitol residues, butyl carbitol residues, isobutyl carbitol residues, triethylene Glycol Monomethyl A Le residues (refers to a hydrocarbon group containing an ether bond other than a hydroxyl group from the ether, the same below), triethylene glycol monoethyl ether residues, triethylene glycol monobutyl ether residue,
2,3-dimethoxy-n-propyl group, 2,2-diethoxyisopropyl group, 3-ethoxy-2-propoxy-
Examples thereof include n-propyl group, nonylphenoxypoly (1-30) ethoxyethyl group, lauroxypoly (1-30) ethoxyethyl group and the like.

At least one compound represented by the general formula (II) and at least one compound represented by the general formula (III) have a molar ratio (former / latter) of 1/9 to 7
A metal salt of an organic phosphoric acid ester obtained by mixing and melting at / 3 is preferable. Among the kinds of metals, zinc, calcium and barium are preferable, and zinc is particularly preferable. The organophosphate metal salt having various substituents as described above can be blended alone or in combination of two or more. The amount of these organic metal phosphates to be compounded is in the range of 0.02 to 5.0 parts by weight, particularly, 100 parts by weight of the vinyl chloride resin.
0.1 to 2 parts by weight is preferable.

In the present invention, an inorganic substance having absorption in the infrared region can be blended for the purpose of improving heat retention. Specific examples include the following. 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 (Hydro-or anhydrous-aluminum /
Magnesium basic carbonate); aluminum / zinc basic carbonate lithium carbonate-aluminum hydroxide inclusion compound, and the like. Among these, aluminum hydroxide, magnesium hydroxide, silicon oxide, magnesium carbonate, and hydrotalcite It is particularly preferable that the compounds do not reduce the transparency of the film.

[0044] _{^{(I): M 2+ (1}} -X) Al 3+ X (OH -) 2 ·
(A ₁ ⁿ⁻ ) _{x / n} · mH ₂ O (In the formula, M ²⁺ represents a divalent metal ion, A ⁿ⁻ represents an n-valent anion, and x, m and n are 0 <x. <
The conditions of 0.5, 0 ≦ m ≦ 2, and 1 ≦ n ≦ 3 are satisfied. ^{) (II): Li + (} Al 3+) 2 (OH -) 6 · (A 2 n-) 1 / n ·
mH ₂ O (In the formula, A ^n- represents an n-valent anion, respectively.
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 (In the formula, 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 (1 + x) / n} · mH ₂ O (In the formula, M ²⁺ represents a divalent metal ion, and A ⁿ⁻ represents an n-valent anion. , M, x and n are 0 ≦ m <
5, satisfying the conditions of 0.01 ≦ x <1 and 1 ≦ n ≦ 3. ) (V): mAl in _{2 O 3 · (n / p} ) M 2 / p O · X · kH 2 O ( wherein, X represents carbonates, M is an alkali metal or alkaline earth metal, respectively, p is It is the valence of the metal M, and m, n and k are 0.3 ≦ m ≦ 1 and 0.3 ≦ n ≦
2 and 0.5 ≦ k ≦ 4 are satisfied. ) These inorganic substances may be added alone or in combination of two or more, and the compounding amount thereof is in the range of 0.5 to 10 parts by weight, particularly 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 the antioxidant, a phenol type antioxidant and a sulfur type antioxidant can be used, and specifically, 2,6-di-butyl-4-methylphenol-
2,2-methylenebis (6-tert-butyl-4-ethylphenol), dilaurylthiodipropionate and the like can be mentioned. These antioxidants can be used alone or in combination of two or more.

Examples of the compound usable 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 raised. These stabilizing aids may be used alone or in combination of two or more.

Examples of the antistatic agent include polyoxyethylene alkylamine, polyglycol ether, p-
Examples thereof include sodium styrene sulfonate. As the mildew-proofing agent and algae-proofing agent, various compounds generally compounded in agricultural vinyl chloride films can be used.
Examples thereof include organic nitrogen compounds, and specific examples include imidazole derivatives, anilide derivatives, urea derivatives, ammonium derivatives, triazine derivatives and phthalimide derivatives. As a colorant, for example, phthalocyanine blue, phthalocyanine green,
Examples include Hansa Yellow, Alizarin Lake, Permanent Red, Quinacridone, and the like. These colorants can also be used alone or in combination of two or more kinds.

The above various resin additives can be selected within a range that does not deteriorate the properties of the film, usually within a range of 5 parts by weight or less relative to 100 parts by weight of the vinyl chloride resin.
To mix the resin additives with the vinyl chloride resin, weigh the required amount, add a ribbon blender, a Banbury mixer,
A conventionally known compounding machine or mixing machine such as a super mixer may be used.

The resin composition thus obtained is formed into a film by a method known per se, for example, a melt extrusion molding method (including a T-die method and an inflation method),
A conventionally known method such as a calender molding method or a solution casting method may be used. The film thickness is 0.03 ~
0.3 mm range, preferably 0.05-0.2 mm
The range is preferably If it is thinner than 0.03 mm,
The film strength is insufficient and tearing is likely to occur.
If it is thicker than m, the work such as cutting and bonding will be adversely affected. The agricultural resin film of the present invention may be provided with a grid pattern, a stripe pattern, or a fine concavo-convex pattern (texture pattern) on at least one surface of the substrate film.

In order to improve durability and dustproofness, it is preferable to form an acrylic resin film on one surface of the agricultural vinyl chloride resin film according to the present invention. The acrylic resin used is 5-40% by weight of hydroxyalkyl (meth) acrylate, and 1 in the molecule.
A polymer obtained by copolymerizing 0 to 20% by weight of an α, β-unsaturated carboxylic acid containing one or two or more carboxyl groups and another vinyl-based monomer copolymerizable therewith is preferable.

Examples of hydroxyalkyl (meth) acrylates 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, 6-hydroxyhexyl methacrylate and the like.

These hydroxyalkyl (meth) acrylate compounds make the resulting acrylic resin easily soluble in an organic solvent, improve the adhesion between the acrylic resin and the base vinyl chloride resin film, and further, stain the film surface. It is a component that greatly contributes to the action of suppressing the migration of the plasticizer that comes out. The proportion of this hydroxyalkyl (meth) acrylate in the acrylic resin is 5% by weight.
If it is less than 40% by weight, the solubility with an organic solvent, the adhesion with a substrate film and the effect of improving durability cannot be sufficiently exerted. On the other hand, if it is more than 40% by weight, the cost becomes high and the cost rises. The effect obtained is not large, which is not preferable.

As the α, β-unsaturated carboxylic acid containing one or more carboxyl groups in the molecule, acrylic acid, methacrylic acid, itaconic acid, maleic acid, maleic anhydride, aconitic acid, fumaric acid, Examples thereof include crotonic acid and itaconic acid. 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 amount of these used is preferably 0.5 to 20% by weight. When it is more than this, the property of the films adhering to each other when the film is moistened with water (blocking property when wet) is enhanced, which is not preferable.

Other vinyl monomers copolymerizable with the hydroxyalkyl (meth) acrylate and the α, β-unsaturated carboxylic acid include (meth) acrylic acid alkyl ester or a mixture thereof with alkenylbenzene. Can be given. Examples of the (meth) acrylic acid alkyl ester include acrylic acid methyl ester, acrylic acid ethyl ester, acrylic acid-n-propyl ester, acrylic acid isopropyl ester, acrylic acid-n-butyl ester, acrylic acid-2-ethylhexyl ester, Acrylic acid decyl ester, methacrylic acid methyl ester, methacrylic acid ethyl ester, methacrylic acid-
Examples thereof include n-propyl ester, methacrylic acid isopropyl ester, methacrylic acid-n-butyl ester, methacrylic acid-2-ethylhexyl ester, and methacrylic acid decyl ester. Generally, an acrylic group having 1 to 20 carbon atoms in an alkyl group. An acid alkyl ester and / or an alkyl ester of methacrylic acid whose alkyl group has 1 to 20 carbon atoms is used.

Examples of the alkenylbenzene used in the present invention include styrene, α-methylstyrene, vinyltoluene and the like. When a monomer composed of a mixture of such an alkenylbenzene and a (meth) acrylic acid alkyl ester is used, it is usually (meth) though it varies depending on the amount of the α, β-ethylenically unsaturated carboxylic acid used. Use 10% of acrylic acid alkyl ester
It is preferable that the content is not less than weight%.

In particular, the acrylic resin of the present invention contains the above-mentioned (meth) acrylic acid alkyl ester and a monomer consisting of a mixture thereof with alkenylbenzene in an amount of 40 to 60.
It is preferable that the content thereof is wt%. When the acrylic resin is surface-treated on the base vinyl chloride resin film, it is possible to mix another resin compatible with the acrylic resin for the purpose of improving the adhesion with the film. As the other resin, a vinylidene fluoride resin, an acrylic resin having a perfluoroalkyl group as a side chain, a cellulose acetate butyrate resin, a silicone resin, or the like is particularly effective.

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

The acrylic resin film formed on one surface of the vinyl chloride resin film is preferably applied by dissolving the acrylic resin in the above-mentioned organic solvent. To form a film of the acrylic resin on the surface of the vinyl chloride resin film, the acrylic resin is dissolved in an organic solvent, and a spray coating method, a roll coating method, a gravure coating method, a reverse coating method, a dip coating method is used. 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. The drying method that can be used is, for example, a hot air drying method, an infrared drying method, or a far infrared drying method. The drying temperature is preferably a temperature at which the organic solvent is scattered, that is, a boiling point of the organic solvent in which the acrylic resin is dissolved or higher. The shorter the drying time, the better. Therefore, it is preferable to dry at a temperature not lower than the boiling point of the organic solvent in the shortest possible time.

Although the thickness of the acrylic resin coating 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, there is a difference in flexibility between the base film and the coating film, so that a phenomenon such as peeling of the coating film from the base film is likely to occur, and cracks are generated in the coating film to reduce strength of the base film. This phenomenon is not desirable. 0.5
When the thickness is smaller than μm, the effect of improving the durability and dustproofness of the base film is not exhibited, which is not preferable. The thickness of the coating is preferably proportional to the thickness of the base film within the above range.

The vinyl chloride resin film for agriculture of the present invention has the following physical properties (a), (b) and (c) as the physical properties of the entire agricultural film when the substrate film is formed into a 0.1 mm thick film. Is further featured. (A) The impact strength at −15 ° C. is 0.5 J or more, preferably 0.7 J or more, more preferably 0.9 J or more.
(There is no particular upper limit, but it is preferably 2 J or less.) (B) Elmendorf tear strength at 23 ° C. is 7.
5N or more, preferably 8.3N or more, more preferably 8.8N or more. (There is no particular upper limit, but preferably 10 N or less) (c) Tensile elongation at break is 300% or more, preferably 320
% Or more (there is no particular upper limit, but preferably 500% or less) The specific measuring method of (a) is as follows:
9 samples of m are prepared, and the thickness of the central part of the sample is measured with a dial gauge specified in JIS B-7503. The above sample is measured by a puncture manufactured by Toyo Seiki Co., Ltd. in a room at -15 ° C. The concrete measuring method of impact strength = measured value (impact value) / measured thickness × nominal thickness (b) is based on JIS6732, and 2
Measure in a room at 3 ° C. The specific measuring method of (c) is based on JSI6723, and is measured in a room at 23 ° C. Further, (d) the straight light transmittance (555 nm) of the agricultural film immediately after production is 85% or more,
It has desirable physical properties.

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

[0062]

EXAMPLES The present invention will be described below based on examples, but the present invention is not limited to the following examples as long as the gist thereof is not exceeded. Examples 1 to 3 and Comparative Examples 1 to 4 (1) Production of vinyl chloride resin film Polyvinyl chloride (degree of polymerization shown in Table 1) 100 parts by weight di-2-ethylhexyl phthalate (parts by weight shown in Table 1) Tricresyl phosphate 5 parts by weight Epoxy resin (trade name "EP-828") 1.5 parts by weight Barium stearate 0.2 parts by weight Zinc stearate 0.4 parts by weight Sorbitan monopalmitate 1.5 parts by weight Methylenebis Amide stearate 0.4 part by weight 2'4-dihydroxybenzophenone 0.03 part by weight β-diketone compound (dibenzoylmethane) 0.1 part by weight Hindered amine light stabilizer 0.1 part by weight (Asahi Denka Kogyo KK: Product name "LA-52") Fluorosurfactant (Product name "Unidyne DS-401") 0.2 parts by weight

The above-mentioned resin raw materials and resin additives were weighed, and the impact modifiers of the types and amounts shown in Table 1 were further mixed therein. After stirring and mixing these for 10 minutes with a super mixer, they were kneaded on a roll heated to 180 ° C., and a vinyl chloride resin film having a thickness of 0.1 mm was produced by an L-type calender device.

(2) Formation of film In a polymerization vessel, 150 parts by weight of isopropyl alcohol and 2 parts of
-Add 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, add 0.5 parts by weight of benzoyl peroxide, and add 8 parts under a nitrogen gas stream.
The polymerization reaction was carried out at 0 ° C. for 10 hours. Isopropyl alcohol was added to the obtained copolymer solution to reduce the solid content to 2
The coating resin was adjusted to 0% by weight. The coating resin was applied to one surface of the base film produced in (1) above by the gravure coating method, and then the solvent was scattered for 10 seconds in a warm air drying oven whose temperature was adjusted to 150 ° C. to disperse the solvent to obtain a thickness. A film 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 2. (3) Initial Appearance The appearance of the films produced in Examples and Comparative Examples was observed with the naked eye, and the linear light transmittance (555 nm) was measured with an EPS-2U type manufactured by Hitachi, Ltd. The evaluation criteria are as follows. Visual appearance ○: Surface gloss and no roughness. Δ: Surface gloss, but rough. ×: Surface has no gloss and is rough. Straight-line light transmittance ⊚: transmittance of 85% or more. ◯: Transmittance of 65% to 84%. Δ: Transmittance of 45% to 64%. X: The transmittance is less than 45%. (4) Physical properties at room temperature Tensile properties: J obtained from the films obtained in Examples and Comparative Examples
Based on IS K6732, the elongation at break was measured in a room at 23 ° C. Elmendorf Tear Strength: The films obtained in Examples and Comparative Examples were measured for Elmendorf tear strength in a room at 23 ° C. according to JIS K6732.

(5) Low temperature physical property impact strength: Nine samples of 10 cm × 10 cm films were prepared, and the thickness of the center part of the sample was measured with a dial gauge specified in JISB-7503. The sample was measured in a room at -15 ° C by a puncture manufactured by Toyo Seiki Co., Ltd. The impact degree is expressed by the following formula. Impact strength = measured value (impact value) / measured thickness x nominal thickness

[0067]

[Table 1]

[0068]

[Table 2]

[0069]

(1) The agricultural vinyl chloride resin film of the present invention is excellent in tear strength and tensile elongation, and
It has excellent physical properties at low temperatures, tearing during spreading,
It has excellent resistance to breakage due to external force (wind, snow, hail, arale, etc.) after stretching. (2) Since the agricultural vinyl chloride resin film of the present invention is excellent in visual appearance (surface gloss, non-roughness) and straight light transmittance, it can give a sufficient amount of light to crops.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C08L 23/28 C08L 23/28 33/10 33/10 51/04 51/04 (72) Inventor Katsuhiro Fujiwara 2 Oike, Iwazuka-cho, Nakamura-ku, Nagoya-shi, Aichi, Nagoya office, Mitsubishi Kagaku MKV Co., Ltd. (72) Inventor Kanako Nikaido, 2 Oike, Iwatsuka-cho, Nakamura-ku, Nagoya, Aichi Mitsubishi Kagaku MKAV Co., Ltd. 72) Inventor Hideto Maekawa 2 Oike, Oike, Iwatsuka-cho, Nakamura-ku, Nagoya, Aichi Mitsubishi Chemical MKV Co., Ltd. Nagoya Business Office F-term (reference) 4F006 AA17 AB43 BA03 BA11 CA06 DA04 4F071 AA12X AA15 AA15X AA20X AA22X AA24 AA24A28XAA25X AA32X AA33X AA34X AA36X AA77 AC07 AC09 AE04 AF15 AF16 AF23 AF26 AF30 AH01 BA01 BB06 BC01 4J002 BB242 BD041 BD051 BD 061 BD071 BD081 BD091 BN162 EE047 EF036 EF056 EF066 EF076 EF116 FD026 FD067 GA01

Claims (5)

[Claims] 1. A vinyl chloride resin having an average degree of polymerization of 1750 or more and 1850 or less and having the following relationship between a weight average molecular weight (hereinafter referred to as “Mw”) and a number average molecular weight (hereinafter referred to as “Mn”). A vinyl chloride resin film for agriculture, characterized in that 40 parts by weight or more and 60 parts by weight or less of a plasticizer is mixed with 100 parts by weight. 1.9 ≦ Mw / Mn ≦ 2.3 2. When molded into a 0.1 mm thick film, (a) the impact strength at −15 ° C. is 0.5 J or more, and (b) the Elmendorf tear strength at 23 ° C. is 7.
The agricultural vinyl chloride resin film according to claim 1, wherein the tensile elongation at break (C) is 5% or more and 300% or more. 3. The agricultural vinyl chloride resin film according to claim 1, which contains a β-diketone compound. 4. An impact resistance improving agent selected from chlorinated polyethylene, methyl methacrylate-butadiene-styrene, and acrylic elastic particles, and the impact-modifying agent as claimed in claim 1. Vinyl chloride resin film for agriculture. 5. The agricultural vinyl chloride resin film according to claim 1, wherein an acrylic resin coating is formed on one or both sides of the vinyl chloride resin film.