JP2001120079A - Resin film for tunnel culture - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a resin film for a tunnel culture, having a good adaptation of the both side end parts or one side end part of the film along its longitudinal direction to the uneven soil surface while maintaining various properties required as the resin film for the tunnel culture and having a good close adherence to the soil surface. SOLUTION: This resin film for the tunnel culture using an agricultural polyolefin-based film obtained by laminating >=2 layers of the polyolefin-based films as a base film is characterized by installing a side end film consisting of an ethylene-α-olefin copolymer obtained by a polymerization using a single site catalyst and/or an ethylene-vinyl acetate copolymer having 10-30 wt.% vinyl acetate monomer content, having 0.850-0.910 g/cc density and 0.1-10.0 g/10 min melt index(MI), side by side with the both side ends or one side end of the above base film along its longitudinal direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin film for tunnel cultivation, and more particularly to a resin film for tunnel cultivation having excellent adhesion to the soil surface at both side ends or one side end along the longitudinal direction of the film.

[0002]

2. Description of the Related Art In tunnel cultivation, as shown in FIG. 1 (a), a plurality of arched frames in which a resin film 1 for tunnel cultivation is erected at predetermined intervals along a longitudinal direction of a vegetation area of a crop P. The cultivation is carried out by covering the vegetation area of the crop P by extending the materials 2, 2,..., Adjusting the growth conditions such as temperature, and creating a favorable environment for the crop P.

[0003] In such tunnel cultivation, for the purpose of temperature control, etc., depending on environmental conditions such as solar radiation, temperature, etc., both end portions or one side along the longitudinal direction of the resin film 1 for tunnel cultivation. The end portion is lifted up and ventilated to prevent the temperature under the coating of the film 1 from rising excessively (FIG. 1 (b) shows only one end portion of the resin film 1 for tunnel cultivation. This is an example of the case where it is lifted up.) Therefore, when the resin film 1 for tunnel cultivation is spread on the frame members 2, 2,... In order to be able to easily lift up the both side ends 1a, 1a or one of the side ends 1a. When it is necessary to keep warm in the evening or at night, the both ends 1a, 1a along the longitudinal direction are laid on the soil surface 3 on both sides of the vegetation area of the crop P when it is necessary to keep heat in the evening or at night. In this way, it is in close contact with the soil surface 3 to ensure heat retention.

[0004] As another method, although not shown, one side end of the resin film for tunnel cultivation is fixed by embedding it in the soil, and only the other side is crawled on the soil surface. In some cases, it can be opened and closed, and the side end that can be opened and closed is lifted up as necessary to ventilate only one side.

As the resin film 1 for tunnel cultivation, a polyvinyl chloride resin film for agricultural use has been conventionally used in many cases. However, agricultural polyvinyl chloride resin film has the advantage of excellent properties such as toughness, durability, heat retention, flexibility, and workability required for resin film for tunnel cultivation. When the film is incinerated in an appropriate incinerator, or when used as combustion energy in a blast furnace, cement kiln, etc., hydrogen chloride gas may be generated and cause environmental problems. I have.

For this reason, in recent years, as an agricultural resin film that does not generate harmful gas during incineration, an agricultural polyethylene film based on low-density polyethylene or a polyolefin-based resin having improved heat insulation properties of the agricultural polyethylene film has been developed. Agricultural polyolefin-based special films having a laminated multilayer structure have attracted attention and have been used. In particular, a polyolefin-based special film for agriculture has a performance close to that of a polyvinyl chloride resin film for agriculture, and is expected to be used as an agricultural resin film in place of the polyvinyl chloride resin film for agriculture in the future.

[0007]

However, when tunnel cultivation is performed using such an agricultural polyolefin-based special film as the resin film for tunnel cultivation, unexpectedly, a situation in which the growth of the crops is unevenly exposed has been revealed. Although polyolefin-based special films for agricultural use have a number of excellent advantages, their spread as resin films for tunnel cultivation is currently stagnant.

The present inventors have conducted intensive studies on the problem of uneven growth in tunnel cultivation using the agricultural polyolefin-based special film, and have found that there is a cause for the flexibility of the film. That is, in the case illustrated in the figure in which both end portions 1a, 1a of the resin film 1 for tunnel cultivation can be opened and closed, when the resin film 1 for tunnel cultivation is composed of an agricultural polyvinyl chloride resin film, Since it has flexibility, both end portions 1a, 1a along the longitudinal direction thereof are
Deformation along the unevenness of the surface makes it well-adapted and has excellent adhesion to the soil surface 3, so that not only the daytime temperature rise but also the evening and nighttime heat retention can be ensured well, whereas the agricultural structure with a laminated structure In the case of a polyolefin-based special film for agriculture, the flexibility thereof is inferior to that of a polyvinyl chloride resin film for agriculture. Therefore, both end portions 1a and 1a along the longitudinal direction lack the adaptability to unevenness of the soil surface 3, and both sides of the film are not provided. End 1
A gap is formed between the a and 1a and the earth surface 3, and naturally, during the daytime, or when it is necessary to keep the heat in the evening or at night, the outside air enters through the gap to be under the film coating. It has been found that temperature unevenness is caused, which causes uneven growth such as poor growth or delayed growth in the crop P, that is, in the side portion of the tunnel.

In order to cope with this, the agricultural polyolefin-based special film has sufficient flexibility so that both end portions 1a, 1a along the longitudinal direction are deformed along the unevenness of the soil surface 3 and are well adapted. What is necessary is to add more flexibility to the agricultural polyolefin-based special film while maintaining various properties such as toughness, durability and workability required as a resin film for tunnel cultivation. Extremely difficult. Such a problem is a problem that is similarly observed even when an agricultural polyethylene film is used, which is inferior in flexibility to an agricultural polyvinyl chloride resin film.

[0010] The present invention has been made in view of the above-mentioned circumstances, and both ends or one end along the longitudinal direction of a film are maintained on a soil surface while maintaining various properties required for a resin film for tunnel cultivation. Familiar with the unevenness of
It is an object to provide a resin film for tunnel cultivation having good adhesion to the soil surface.

[0011]

The above object is achieved by the following invention.

(Claim 1) In a resin film for tunnel cultivation using a polyolefin-based special film for agricultural use as a base film in which two or more layers of a polyolefin-based resin are laminated, both ends along the longitudinal direction of the base film or At one end, an ethylene-α-olefin copolymer having a density of 0.850 to 0.910 g / cc, a melt index (MI) of 0.1 to 10.0 g / 10 min, and polymerized using a single-site catalyst is used. A resin film for tunnel cultivation, wherein a side end film comprising an ethylene-vinyl acetate copolymer having a content of a polymer and / or a vinyl acetate monomer of 10 to 30% by weight is continuously provided.

(Claim 2) The width of the base film is 1.5 to
4.0m, width of side edge film is 10-100cm
The resin film for tunnel cultivation according to claim 1, wherein:

(Claim 3) In a resin film for tunnel cultivation using an agricultural polyethylene film made of low-density polyethylene as a base film, a density of 0. 0 at both ends or one end along the longitudinal direction of the base film. 850
Content of an ethylene-α-olefin copolymer and / or a vinyl acetate monomer polymerized using a single-site catalyst having a melt index (MI) of 0.1 to 10.0 g / 10 min at 0.910 g / cc. Amount is 10-30
A resin film for tunnel cultivation, wherein a side end film made of an ethylene-vinyl acetate copolymer in a weight percentage is continuously provided.

(Claim 4) The width of the base film is 1.5 to
4.0m, width of side edge film is 10-100cm
The resin film for tunnel cultivation according to claim 3, wherein:

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to a case illustrated in the drawings, in which both ends of a tunnel can be opened and closed.

The resin film for tunnel cultivation of the present invention comprises:
Density of 0.850 to 0.8 mm on both sides of the base film covering the vegetation area of the crop by being spread on the frame material.
The melt index (MI) is 0.9 to 10.0 g / 10 min at 0.910 g / cc, and the content of the ethylene-α-olefin copolymer and vinyl acetate monomer polymerized by using a single-site catalyst is: 10-30% by weight
And a side end film made of one or both of the ethylene-vinyl acetate copolymers.

Hereinafter, in the present invention, the region of the side end film continuously provided on both side ends along the longitudinal direction of the base film is referred to as "region A", and the region of the base film is referred to as "region B" (FIG. 2). reference). “A region” is a region covering the vegetation region of the crop P, and “B region” is a soil surface 3 on both sides of the vegetation region.
This is an area that can be crawled up (see FIG. 1A).

(Region A) Ethylene used in the present invention
The α-olefin copolymer is an ethylene-α-olefin copolymer polymerized using a single-site catalyst, and is disclosed in JP-A-58-19309 and JP-A-59-95.
No. 292, JP-A-60-35005, JP-A-60-35006, JP-A-60-35007, JP-A-60-35008, JP-A-60-35
No. 009, Japanese Patent Application Laid-Open No. 60-130341, Japanese Patent Application Laid-Open No. 3-163088, European Patent Application Publication No.
No. 4,204,436, U.S. Pat. No. 5,055,438 and WO 91/04257, single-site catalysts, in particular metallocene / alumoxane catalysts, or, for example, WO 92/01.
Copolymerization of ethylene as a main component and α-olefin as a subcomponent using a metallocene compound as described in JP-A-723, etc., and a catalyst comprising a compound which reacts with the metallocene compound to form a stable ion. It is obtained by doing.

As the α-olefin used for copolymerization with ethylene, it is preferable to use an α-olefin having 4 to 12 carbon atoms from the viewpoint of productivity and physical properties. For example, an α-olefin having 4 to 12 carbon atoms is used. 1-butene, 1-pentene, 1-hexene, 1-octene, 1-heptene, 4-
Methylpentene-1,4-methylhexene-1,4,4
-Dimethylpentene-1 and the like. Further, those having 6 to 8 carbon atoms are more preferable.

It is preferable to copolymerize 2 to 60% by weight, preferably 5 to 50% by weight of these α-olefins and 40 to 98% by weight, preferably 50 to 95% by weight of ethylene.

The polymerization method of ethylene and α-olefin may be either high-pressure polymerization or low-pressure polymerization, but from the viewpoint of the blocking properties and strength of the resulting film, those obtained by low-pressure polymerization are preferred.

In the present invention, the ethylene-α-olefin copolymer polymerized using the above-mentioned single-site catalyst can be used alone or in an appropriate combination of two or more.

The ethylene-α-olefin copolymer used in the present invention has a density of 0.850 to 0.910 g / c.
Use an ultra-low density c. 0.850 g /
If it is smaller than cc, the heat resistance is insufficient, and it is unstable during molding. If it is larger than 0.910 g / cc, the flexibility is insufficient and the effects of the present invention cannot be obtained. More preferred densities range from 0.860 to 0.905 g / cc.

The melt index (MI) of the ethylene-α-olefin copolymer used in the present invention is as follows:
What shows 0.1 to 10.0 g / 10 minutes is used.
The melt index (MI) is a value measured according to JIS K-6758. If the melt index is lower than this range, the flexibility is poor, and if it is high, the molding stability is poor. Further, the range is more preferably 0.5 to 4.0 g / 10 minutes.

The above-mentioned ethylene-α-olefin copolymer contains various additives generally used in agricultural resin films, such as silica, zeolite and carion as antiblocking agents, fatty acid amides as slip agents, and phenols as antioxidants. System stabilizer, phosphorus stabilizer, sulfur stabilizer, hindered amine stabilizer as light stabilizer, calcium stearate as dispersant, phthalocyanine blue, phthalocyanine green, quinacridone red as colorant, polyhydric alcohol fatty acid as antifoggant Esters, alkylamines and phosphates as antistatic agents, benzophenone and benzotriazole as ultraviolet absorbers, silica, hydrotalcite, aluminum hydroxide and the like as heat insulators can be added as required.

The above-mentioned ethylene-α-olefin copolymer may be blended with a known high-density polyethylene or low-density polyethylene for the purpose of adjusting moldability.
In this case, it is necessary that the flexibility of the obtained side end film is not impaired, and it is preferable that the amount is 50% by weight or less of the whole.

Next, the ethylene-vinyl acetate copolymer used in the present invention has a vinyl acetate monomer content of 5 to 5.
30% by weight. If the content of the vinyl acetate monomer is less than 5% by weight, the flexibility is insufficient, and if it exceeds 30% by weight, it becomes sticky and the handling becomes poor. More preferably, it is in the range of 10 to 20% by weight.

This ethylene-vinyl acetate copolymer also has
Various additives generally used for agricultural resin films, such as the above-mentioned ethylene-α-olefin copolymer, such as antiblocking agents, slip agents, antioxidants, light stabilizers, dispersants, coloring agents, and antifogging agents If necessary, an antistatic agent, an ultraviolet absorber, a warming agent and the like can be added. Further, a known low-density polyethylene or the like may be blended. In this case as well, the amount is preferably 50% by weight or less based on the whole in order not to hinder the flexibility of the obtained resin film.

In the resin film for tunnel cultivation of the present invention, the raw materials of the side end films connected to both ends along the longitudinal direction of the base film include these ethylene-α-olefin copolymer and ethylene-vinyl acetate. Either one of the copolymers may be used, or both may be used as a blend. Alternatively, both may be laminated to form a multilayer structure. When both are used by blending, the blending ratio of the ethylene-α-olefin copolymer and the ethylene-vinyl acetate copolymer is free, but from the viewpoint of dispersibility, an extruder with good kneading properties may be used. It is preferable to use a compatibilizer.

(Region B) The base film of the resin film for tunnel cultivation of the present invention contains a polyolefin-based resin
An agricultural polyolefin-based special film formed by laminating layers or more or an agricultural polyethylene film made of low-density polyethylene can be used.

The agricultural polyolefin resin film obtained by laminating two or more layers of the polyolefin resin includes, for example, a low-density polyethylene and / or ethylene-vinyl acetate as an outer layer of an intermediate layer made of an ethylene-vinyl acetate copolymer. A resin film obtained by laminating a copolymer is exemplified.

In this case, the ethylene-
The vinyl acetate copolymer may be composed of an ethylene-vinyl acetate copolymer in which the content of the vinyl acetate monomer used in the “A region” is 5 to 30% by weight,
Thereby, the physical properties of the “A region” and the “B region” can be made close to each other, and the strength of the joint can be improved.

The agricultural polyethylene film made of low-density polyethylene has a density of 0.910 to 0.930 g /
It is a polyethylene film in the range of cc, and a film called agricultural poly can be used.

(Width of Region A and Region B) In the present invention,
The width of the base film is in the range of 1.5 to 4.0 m, while the width of the side end film is in the range of 10 to 100 cm. If there is such a relationship between the widths, the object of the present invention can be achieved.

(Formation of Film) The resin film for tunnel cultivation of the present invention can be manufactured by simultaneously forming “A region” and “B region” using an inflation molding method and a T-die molding method. it can.

In the case of the inflation molding method, "B
The resin material constituting “A region” is supplied to a part of the inflation die that supplies the resin material constituting “region” to form a film, and then the “A region” is cut out to form the “B region”. "A area" at both ends along the longitudinal direction
Can be molded to form the resin film for tunnel cultivation of the present invention in which are integrally connected.

In the case of the T-die molding method, the resin material constituting the “A region” is supplied from both ends of the die for molding the “B region”, so that both ends along the longitudinal direction of the “B region” are provided. The resin film for tunnel cultivation of the present invention in which the “A region” is integrally and continuously provided can be formed.

(Film Thickness) The thickness of the resin film for tunnel cultivation of the present invention is 20 to 100 μm, preferably 3 to 100 μm.
0 to 70 μ.

In the embodiment described above, the side end films ("A region") are continuously provided on both sides of the base film ("B region"). Embed the soil in the soil to seal it tightly, and squeeze the other end only on the soil surface so that it can be opened and closed. When cultivation management is performed as described above, a resin film for tunnel cultivation may be provided by providing a side end film (“A region”) only on one side end of the base film (“B region”). It goes without saying that it is a good thing, and it is clear that a similar effect can be obtained in this case.

[0041]

According to the present invention, while maintaining various properties required for a resin film for tunnel cultivation, both side ends or one side end along the longitudinal direction of the film are well adapted to irregularities on the soil surface. In addition, it is possible to provide a tunnel cultivation resin film having good adhesion to the soil surface.

[Brief description of the drawings]

FIG. 1A is a view showing a use state of a film in tunnel cultivation, and FIG. 1B is a view showing a state where one end of the film is lifted up.

FIG. 2 is a schematic perspective view showing an example of the film of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Resin film for tunnel cultivation 1a Side end part 2 Frame material 3 Soil surface P Crops

Continuation of the front page (72) Inventor Naoki Fujino 2298 1-4 Junwell Chojabara, Ichihara-shi, Chiba F-term in Mikado Chemical Co., Ltd. (Reference) 2B024 DB01 EA01 2B029 EB03 EB16 EC02 EC06 EC09 EC20 4F100 AK06B AK06D AK62C AK68A AK68B AK68B BA02 BA03 BA06 BA10A BA10C GB01 JA06C JA13C JL08C YY00C

Claims (4)

[Claims] 1. A tunnel cultivation resin film comprising a polyolefin-based special film obtained by laminating two or more layers of a polyolefin-based resin as a base film, wherein the base film is provided at both side ends or one side end along a longitudinal direction of the base film. An ethylene-α-olefin copolymer having a density of 0.850 to 0.910 g / cc, a melt index (MI) of 0.1 to 10.0 g / 10 min, and polymerized using a single-site catalyst; Alternatively, a resin film for tunnel cultivation, wherein a side end film made of an ethylene-vinyl acetate copolymer having a vinyl acetate monomer content of 10 to 30% by weight is continuously provided. 2. The resin film for tunnel cultivation according to claim 1, wherein the width of the base film is 1.5 to 4.0 m and the width of the side end film is 10 to 100 cm. 3. A resin film for tunnel cultivation using an agricultural polyethylene film made of low-density polyethylene as a base film, wherein the density is 0.850-0 at both side ends or one side end along the longitudinal direction of the base film. .910
g / cc and melt index (MI) 0.1-1
An ethylene-α-olefin copolymer which is 0.0 g / 10 min and is polymerized using a single-site catalyst, and / or an ethylene-vinyl acetate copolymer having a vinyl acetate monomer content of 10 to 30% by weight. A resin film for tunnel cultivation, wherein side end films are continuously provided. 4. The resin film for tunnel cultivation according to claim 3, wherein the width of the base film is 1.5 to 4.0 m, and the width of the side end film is 10 to 100 cm.