JPH0452736B2 - - Google Patents

Description

[Detailed description of the invention]

<Industrial Application Field> The present invention relates to an agricultural film that has the effect of repelling pests to crops during crop cultivation. <Conventional technology> Conventionally, transparent or translucent polyethylene films, ethylene vinyl acetate copolymer films, and soft vinyl chloride resins have been used to grow vegetables such as fruit vegetables and leafy vegetables, flowers, and fruit trees. Films have been used to cover greenhouses, tunnels, and the ground for growing crops. The coating of the house and tunnel is inside the house during the low temperature period.
This is done to promote crop growth while maintaining a high temperature inside the tunnel, and to save energy in heating the greenhouse during the coldest months.In general, mulching, which covers the ground for growing crops, reduces moisture in the soil. This is done to maintain soil temperature, raise soil temperature, and prevent fertilizer components from being washed away. In recent years, with the spread and development of cover cultivation as mentioned above,
It is becoming more and more common for harmful pests to fly to cultivated crops, become parasitic, and cause a great deal of damage, and damage caused by southern yellow thrips and aphids is especially serious in warm southwest regions such as Okinawa, Kyushu, Shikoku, Chugoku, and Kinki. This has become a serious problem. Methods to control these pests include using pesticides such as repellents and insecticides, and supplementing with traps using pheromones and adhesive tapes that have the effect of attracting pests.
Some of them have been put into practical use. <Problems to be solved by the invention> However, these methods also have problems; for example, when using pesticides, resistance develops in pests over time, and it is necessary to repeatedly develop pesticides with stronger insecticidal properties. Therefore, there are inherent problems that develop beyond the two types of pollution, such as environmental pollution, such as increased toxicity to human stock and increased accumulation in the soil. As a pest control method that does not cause the above-mentioned problems, flying pests are prevented by covering cultivated crops or the ground with a film that has a high reflectance of sunlight and has a metal such as aluminum deposited on the film surface. Methods have been proposed and put into practical use for controlling pests in covered houses and tunnels using methods and films that cut out near-ultraviolet rays.
However, regarding these methods, the former is not suitable for covering greenhouses, tunnels, etc. because of the high product cost and high solar reflectance, but low light transmittance, and when mulching the cultivation ground. However, the problem is that the soil temperature does not rise easily, making it impractical except for special uses that take advantage of this characteristic. Although the latter has excellent pest control effects in covered greenhouses and tunnels, it has problems such as poor coloring of eggplants and flowers, which limits the crops it can be used on. Furthermore, the use of mulch has no pest control effect at all. <Means for Solving the Problems> In view of these circumstances, the inventors have worked diligently to promote the growth of cultivated crops by increasing the soil temperature of the crop cultivation ground and controlling pests that fly to and parasitize the crops. As a result of studies, it was discovered that ultraviolet rays of a specific wavelength reflected by mica pieces coated with fine particles of titanium oxide were extremely effective in pest control, and the present invention was achieved. That is, the present invention relates to a pest control film formed from a thermoplastic resin composition containing mica pieces coated with fine particles of titanium oxide. The present invention will be explained in detail below. The thermoplastic resin used in the present invention is not particularly limited, but includes low density polyethylene, high density polyethylene, ethylene-butene-1 copolymer, ethylene-4-methylpentene-1 copolymer, and ethylene-vinyl acetate copolymer. Used are ethylene homopolymers and copolymers, polypropylene, vinyl chloride resin, etc. These can be used alone or in combination. The film of the present invention can be manufactured by the following steps. A thermoplastic resin composition containing mica pieces coated with fine titanium oxide particles is prepared by melting the resin using a normal Banbury mixer, two-roll kneader, or extrusion kneader. Obtained by mixing and kneading pieces. The obtained resin composition can be formed into a film using a film processing machine such as ordinary inflation film processing, T-die film processing, or calendar processing. As the mica pieces coated with particulate titanium oxide used in the present invention, conventionally known mica pieces can be used. For example, Teika Pearl TP650 manufactured by Teikoku Kako Co., Ltd. can be mentioned. In addition, in order to obtain a laminated film in which a transparent thermoplastic resin layer is provided on the inner surface, inner or outer surface of a resin layer containing mica pieces coated with fine titanium oxide, two extrusion machines equipped with two-layer extrusion dies are required. A resin composition containing mica pieces coated with fine titanium oxide particles and a transparent thermoplastic resin composition are extruded separately from a machine to form a two-layer film, or two extruders equipped with three-layer extrusion dies are used. The intermediate layer can be formed into a three-layer film by laminating a transparent thermoplastic resin layer on the inner and outer surfaces of a resin layer containing mica particles coated with fine titanium oxide particles. In the case of these laminated films, the resins of the mica flake-containing film layer coated with fine titanium oxide particles and the transparent film layer may be the same or different. The content of mica pieces coated with fine titanium oxide is 0.5 to 20% by weight.
is preferable, and 1 to 5% by weight is more preferable since it has high ultraviolet reflectivity and does not substantially block visible light transmittance. The thickness of the film is not particularly limited as it varies depending on the application, but the thickness of the film layer containing mica pieces coated with fine titanium oxide may be 5 to 50μ,
The total film thickness of laminated transparent film layers is
It is preferable to set it as 10-100 micrometers. <Effects of the invention> The films obtained as described above are house
It can be used to cover tunnels and mulch the ground for crop cultivation, and it reflects ultraviolet rays at specific wavelengths, thereby preventing the arrival of crop pests such as aphids and southern thrips. <Examples> Next, the present invention will be explained with reference to Examples, but these Examples are merely illustrative and are not limited thereto. Example 1 Low density polyethylene (density: 0.924 g/cm ² , MI:
1.5g/10 minutes) 100 parts by weight Mica piece coated with fine titanium oxide (Teika Pearl TP650, fine particle titanium oxide coating thickness 0.08μ, mica piece particle diameter approximately 30μ, Teikoku Kako Co., Ltd.)
) 2.0 parts by weight Monoglycerol monostearate 0.5 parts by weight Tinuvin, a hindered amine weathering agent, is added to the above formulation.
0.1 part by mass of 622 was added, and after kneading for 10 minutes at a resin temperature of 150 to 160°C using a 5-panbury mixer, granulated pellets were produced using an extruder. Next, use an inflation film processing machine to heat the melting zone to 180℃.
A film with a thickness of 20 μm was obtained under the condition of a die temperature of 180°C. The film performance test results are shown in FIG. 1 and Tables 1-2. Example 2 In Example 1, low density polyethylene was replaced with ethylene-butene-1 copolymer (density: 0.925, g/cm ² ,
A film with a thickness of 20 μm was obtained in the same manner as in Example 1, except that MI: 2 g/10 minutes). The film performance test results are shown in FIG. 1 and Tables 1-2. Example 3 Ethylene-butene-1 copolymer (density: 0.925
g/cm ² , MI: 2g/10 min) 100 parts by weight Mica pieces coated with fine titanium oxide (Teika Pearl TP650 manufactured by Teikoku Kako Co., Ltd.) 8.0 parts by weight Monoglycerin monostearate 2.0 parts by weight Hindered amine weathering resistant in the above formulation drug tinuvin
A mixed resin A was obtained in the same manner as in Example 1 by adding 0.1 part by weight of 622. Further, using the same ethylene-butene-1 copolymer as above, granulated pellets were obtained from the above without blending mica pieces coated with fine titanium oxide and monoglycerol monostearate. Hereinafter, this mixed resin will be referred to as B mixed resin. Next, using a two-layer inflation film processing machine equipped with two extruders and a two-layer die, the above mixed resin A and mixed resin B were put into separate extruders, the melting zone was set at 220°C, the die was A two-layer laminated film was molded while melting and adhering the mixed resin layer A and the mixed resin layer B in a two-layer die at a temperature of 200°C. The obtained film was a two-layer film with a thickness ratio of mixed resin layer A/mixed resin layer B to 1/3 and a total thickness of 80 μm. The film performance was tested with the A mixed resin layer on the outside, and the results are shown in FIG. 1 and Tables 1 and 2. Example 4 A multilayer inflation film molding machine equipped with a three-layer inflation die was used to mix the A mixed resin and B mixed resin used in Example 3, and the A mixed resin was passed through an extruder into the middle layer of the die. the melting zone
The B mixed resin was supplied to the inner and outer layers through the other extruder at a melting zone of 190°C and a die temperature of 190°C.
The resin supplied to each layer is laminated inside the die,
A three-layer laminated film with a total film thickness of 30 μm was obtained, consisting of an inner layer of 12 μm, an intermediate layer of 6 μm, and an outer layer of 12 μm. The performance of the obtained film is shown in FIG. 1 and Tables 1 and 2. Comparative Example 1 Using only the B mixed resin of Example 3, the thickness was 30μ
A single-layer transparent blown film was obtained.
Film performance test results are shown in Figure 1 and Tables 1-2.
It was shown to. Comparative Example 2 Film performance was tested using a commercially available aluminum-deposited polyethylene film (manufactured by Reiko Co., Ltd., thickness 50 μm). The results are shown in FIG. 1 and Tables 1 and 2. Comparative Example 3 Ethylene-butene-1 copolymer (density: 0.925,
MI: 2) 100 parts by weight of titanium oxide (Teikoku Kako Co., Ltd.) 8.0 parts by weight of monoglycerin monostearate 2.0 parts by weight of the hindered amine weathering agent Tinuvin in the above formulation
A C mixed resin was obtained in the same manner as in Example 1 by adding 0.1 part by weight of 622. Next, using a two-layer inflation film processing machine equipped with two extruders and a two-layer die,
The mixed resin and the B mixed resin of Example 3 were put into separate extruders, and the C mixed resin layer and the B mixed resin layer were melted and bonded in a two-layer die under the conditions of a melting zone of 220°C and a die temperature of 200°C. A two-layer laminated film was molded. The obtained film was a two-layer film with a thickness composition ratio of 1/3 of C mixed resin layer/B mixed resin layer and a total thickness of 30 microns. The film performance was tested with the C mixed resin layer on the outside, and the results are shown in FIG. 1 and Tables 1 and 2. The performance tests for the films shown in Examples and Comparative Examples were conducted in the following manner. Total light transmittance The total light transmittance of the film was measured using a haze tester manufactured by Toyo Seiki. Ultraviolet and visible light reflectance The ultraviolet and visible light reflectance of the film was measured using a Hitachi self-recording spectrophotometer model 330. Pest repellent effect: Cultivated crops are planted with cucumbers by mulching film in ridges of 90 cm in width, 25 m in length, and 20 cm in height. The number of cucumbers (out of 80 cucumber leaves) was investigated. The growth performance of cucumbers was investigated under a mulching film similar to the insect repellent effect, and the yield rate at harvest was expressed as 100 for bare soil.

【table】

【table】 [Brief explanation of the drawing]

FIGS. 1-a and 1-b show graphs of the reflectance of the film for ultraviolet to visible light (wavelengths of 0.2 μ to 0.8 μ).

Claims (1)

[Scope of Claims] 1. An agricultural pest repellent film characterized by being formed from a thermoplastic resin composition containing 0.5 to 20% by weight of mica pieces coated with fine particles of titanium oxide. 2. A film according to claim 1, characterized in that the film is formed by providing a transparent thermoplastic resin layer on the inner surface, inner surface, or outer surface of a thermoplastic resin layer containing mica pieces coated with fine particles of titanium oxide. film.