JPH09248069A - Insect multifilm - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an insect multifilm effective for fruits and flowers or the like by which full light beam transmissivity is lowered, the increase of ground heat is suppressed, the growth of weed is prevented and the sprinkle of insecticide can drastically be decreased by laminating a thermoplastic resin layer containing a insect pest repellent onto the surface of a specified base layer. SOLUTION: The base layer is composed of thermoplastic resin such as polyethylene containing aluminum powder preferably for 7-15wt.% (for the thermoplastic resin) having an average particle diameter from 3μm to 20μm, and the thermoplastic resin layer containing the insect pest repellent such as pyrethrin preferably for 0.1-10% is laminated on one surface at least or preferably on both the sides of the base layer. In this case, it is preferable that the thickness of this insect multifilm is within the range from 15μm to 60μm.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an agricultural mulch film, and more particularly to an insect repellent mulch film for preventing damage of agricultural products by harmful insects.

[0002]

2. Description of the Related Art Conventionally, a film formed by adding aluminum powder to a thermoplastic resin such as polyethylene or polyvinyl chloride, a so-called silver film, has a pest repellent action, so that lettuce, radish, carrot, eggplant are required. It is widely used as a mulch film for cultivation of crops such as. However, the silver film is intended to evade flying insect pests such as southern blue thrips and aphids by reflecting light rays, especially ultraviolet rays that pests dislike, and slugs and diamondback moth larvae crawling across soil. It did not have any repellent effect against such harmful insects.

On the other hand, in recent years, the problem of pesticide contamination has become more serious among farmers, and the number of patients with bronchitis and liver damage is increasing rapidly in the regions where facility horticulture is active. Under these circumstances, a silver film is used for the purpose of reducing pesticide spraying, and since it is unprotected against pests that crawl through the soil as described above, a film having a higher insecticidal effect is strongly desired. It was

[0004]

The problem to be solved by the present invention relates to an insect-repellent mulch film capable of repelling not only insect pests that come in, but also insect pests that move along soil.

[0005]

Means for Solving the Problems As means for solving the above problems, the base material layer is made of a thermoplastic resin containing aluminum powder, and at least one surface thereof is
Provided is an insect-repellent mulch film characterized by laminating a thermoplastic resin layer containing a pest repellent, and further laminating a thermoplastic resin layer containing a pest repellent on both surfaces of a base material layer. The above insect-repellent mulch film is provided.

That is, according to the present invention, a thermoplastic resin layer containing aluminum powder is used as a base material layer to repel insects flying in, and at least one surface layer contains a pest repellent. By forming it with a thermoplastic resin,
It repels pests crawling through the soil.

The thermoplastic resin used in the surface layer and the base material layer of the insect mulch film of the present invention is not particularly limited as long as it can be formed into a film, and for example, polyethylene or ethylene-vinyl acetate copolymer is used. Olefin resin such as, vinyl chloride resin such as polyvinyl chloride,
Polyester resins such as polyethylene terephthalate and polybutylene terephthalate, acrylic resins, polyamide resins, and blends of two or more of these resins are included. Among them, as the mulch film, an olefin resin such as low density polyethylene or linear low density polyethylene is particularly preferable from the viewpoints of economy and easy disposal.

It is preferable that these thermoplastic resins have good transparency when formed into a film, so that the excellent reflection characteristics of the aluminum powder can be exhibited in a form close to that as it is. Further, in order to further improve the transparency of the film, the resin may be added with a crystallization inhibitor, or may contain a metal oxide defoaming agent or the like in order to suppress foaming during film formation.

The aluminum powder added to the base layer of the insect mulch film of the present invention has an average particle size of 1
To 30 μm, preferably 3 to 20 μm, scale-like, flake-like, or needle-like, and these are used alone or in combination, of which scale-like aluminum powder gives high reflectivity to the film. The aluminum powder in other shapes helps improve the light-shielding property of the film.

Here, the amount of aluminum powder added is 3 to 20% by weight, preferably 7 to 15% by weight, based on the thermoplastic resin, and the amount of aluminum powder added to the thermoplastic resin is less than 3% by weight. Has a low reflectance and therefore has a poor repellent effect against incoming pests. Further, if the amount of aluminum powder added exceeds 20% by weight, not only the effect commensurate with that cannot be obtained, but also the draw-down property at the time of film molding is poor, the stability of film formation is deteriorated, and the film strength becomes weak. The problem to say arises.

In the insect mulch film of the present invention, the insect repellent added to at least one surface layer of the insect mulch film includes pyrethroids such as pyrestrin and allethrin, and organic phosphorus such as foxime, pyridafenthion and tetrechlorvinphos. Examples thereof include system insecticides, sap such as ovaknone, nomiline, limonin, and deoxylimonin extracted from natural bark, and a mixture of 3,6-dichloropyritazine and parachlorometaxylenol. Among these, the mixture of 3,6-dichloropyritazine and parachlorometaxylenol is the most preferable from the viewpoints of safety, film productivity, plant environmental hygiene and the like. Further, the amount of the pest repellent added varies depending on its type, so it cannot be said unconditionally, but generally 0.1 to 1
0% by weight is preferred.

In the present invention, in addition to the above-mentioned additives, generally known antioxidants, antiblocking agents, lubricants, antifogging agents, colorants, fillers and the like may be appropriately blended if necessary. Absent.

The insect repellent mulch film of the present invention comprises a composition for a base layer comprising a thermoplastic resin and aluminum powder in one extruder, and a composition for a surface layer comprising a thermoplastic resin and a pest repellent. After being melt-kneaded by each extruder, the mixture is extruded by a so-called co-extrusion method in which it is merged into one die and laminated, and then formed into a film by an inflation method, a T-die method or the like. Also, a plurality of films formed separately may be bonded together via an adhesive or the like. The thickness of the insect mulch film of the present invention is usually 10 to 200.
It is preferable that the thickness is in the range of 15 to 60 μm. Further, the base material layer preferably occupies 10 to 80% of the total film thickness, and more preferably 20 to 60%, from the viewpoints of stability during film formation and reflectance.

Further, in the present invention, even if the surface layer containing the pest repellent is provided only on one surface of the base material layer, it is possible to repel the pests that crawl the soil to some extent. Are difficult to distinguish, and they may be laid by mistake when the film is stretched. Therefore, in order to avoid such troubles and make the pest repellent effect more reliable, it is preferable to provide the surface layer containing the pest repellent on both surfaces of the base material layer.

[0015]

EXAMPLES The insect mulch film according to the present invention will be described below in more detail with reference to Examples, but the present invention is not limited thereto. Example 1 Linear low-density polyethylene raw material (MI 0.8 g / 10 mi
n, density 0.923 g / cm3) Silver masterbatch 2 containing 40% by weight of aluminum particles in 65% by weight
5% by weight, and 10% by weight of a low density polyethylene resin-based weathering agent masterbatch containing 4% by weight of a weathering agent.
The composition (A) for the base layer formed by blending, and a linear low-density polyethylene raw material (MI 0.8 g / 10 min, density 0.92
3 g / cm3) 82% by weight, 4% by weight of an equal mixture of 3,6-dichloropyritazine and parachlorometaxylenol
8% by weight of the low-density polyethylene-based pest repellent masterbatch contained therein and 10% by weight of the low-density polyethylene resin-based weatherproofing masterbatch as the surface layer resin composition (B), separately 3 units Inflation co-extrusion molding under the conditions of processing temperature 190 ℃, extrusion rate 20 kg / hour, take-up speed about 13 m / min,
A three-layer insect repellent mulch film comprising a base material layer and both surface layers positioned so as to sandwich the base material layer was obtained. The thickness of the mulch film is 6 μm for both surface layers and 8 μm for the base material layer.
The total thickness was 20 μm. The light reflectance of the film showed a maximum reflectance of 62% with respect to the light having a wavelength of 263 nm, and the total light transmittance was 4.9%.

Comparative Examples 1 and 2 Further, for comparison, a transparent film having a thickness of 20 μm (Comparative Example 1) prepared by blending a low-density polyethylene raw material with 10% by weight of a weather resistant masterbatch, and a resin composition (B) for a surface layer. By the same method as in the above-mentioned example except that the pest repellent masterbatch of No. 2 was used, the two surface layers each had a three-layer structure of 6 μm and the substrate layer had a total thickness of 20 μm, and the light reflectance was 61%. A silver film having a total light transmittance of 5.0% (Comparative Example 2) was produced.

The thus obtained three kinds of films were subjected to a strawberry (cultivar: Toyonoka) cultivation test in a field in Saga prefecture, and the pest control effect was examined under pesticide-free conditions.

In the test, two insect test film sections obtained in the above examples, two transparent film sections obtained in Comparative Example 1 and two silver film sections obtained in Comparative Example 2 were provided, and a total of 6 sections were constituted. . The number of strains in one test plot was 12. In addition, the cultivation method was fixed planting on September 20, soil cultivation in a house, and 6 pests were selected from each test plot for the pest occurrence status, and 3 leaves were randomly selected for each pest, depending on the flying pests (aphids). The damage rate was measured and the insect damage to the slug fruits was examined. Table 1 shows the results.

[0019]

[Table 1]

From the above test, the insect repellent mulch film of the present invention was found to have an excellent repellent effect not only for flying pests but also for pests such as slugs that crawl on the ground.

[0021]

[Effect] The mulch film according to the present invention repels pests flying in the base material layer and repels pests crawling in the soil with the resin layer containing the pest repellent. Therefore, the spraying of the insect repellent can be significantly reduced as compared with the conventional case.

Further, the mulch film has a low total light transmittance and is excellent in the effect of suppressing an increase in soil temperature and the effect of preventing overgrowth of weeds. Further, since it has a high light reflectance, it can be used as a reflective film for coloring apples, tangerines, peaches, fruits such as carnations, flowers, etc., and increasing the sugar content.

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Claims (2)

[Claims] 1. The base material layer is made of a thermoplastic resin containing aluminum powder, and at least one surface thereof is provided with:
An insect-repellent mulch film comprising a thermoplastic resin layer containing a pest repellent, which is laminated. 2. The insect-repellent mulch film according to claim 1, wherein a thermoplastic resin layer containing a pest repellent is laminated on both surfaces of the base material layer.