JPH0837942A - Agricultural covering material with excellent durability - Google Patents

Abstract

(57) [Summary] [Purpose] Can be extended outdoors for a long time,
It is an object of the present invention to provide an agricultural covering material that is useful for cultivating various useful crops as a greenhouse covering material that replaces glass. [Composition] Containing at least cerium oxide fine powder, 3
At least 3 transmission of UV in the wavelength range of 00-330 nm
A highly durable agricultural coating material made of a fluororesin film that blocks 0% and has a visible light transmittance of at least 70% in the wavelength range of 400 to 800 nm.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an agricultural coating material,
More specifically, the present invention relates to a covering material for agriculture which is capable of being extended for a long period of time and which has an excellent durability and partially shields light in a specific wavelength range.

[0002]

2. Description of the Related Art Conventionally, polyethylene film, ethylene-vinyl acetate copolymer film, polyester film, vinyl chloride resin film and the like have been used as coating materials for tunnels and pipe houses. It occupies the most in terms of workability, price, and heat retention. However, since these resins have poor outdoor durability, the coating period is 1 to 2 years, and the farmer refills the coating material each time.

On the other hand, in recent years, full-scale large-scaled houses have been adopted for the purpose of labor saving of house management, expansion of cultivation area, high-grade cultivation of crops, extension of house life, and the like. For this large-scale house, covering materials such as polyester resin plate, polycarbonate resin plate, hard vinyl chloride resin plate, acrylic resin plate, fiber reinforced plastic plate, etc. have been used as covering materials for spreading for about 5 years. However, since these coating materials have a large thickness, they have to be spread using a large-sized dedicated base material, which has the drawback that the workability is very complicated and relatively expensive. Further, polyester resin plates, polycarbonate resin plates, hard vinyl chloride resin plates, acrylic resin plates and the like have drawbacks that cracks are likely to occur due to the hail and the cracks are likely to propagate.

Further, as a durable coating material that can be used for 10 years or more, there is plate glass, which is not only expensive, but also easily broken, and once broken, fine glass fragments are removed in the house. There is a problem that the soil must be replaced.

In order to solve these problems, for example, Japanese Patent Application Laid-Open No. 64-43535 proposes an agricultural coating material made of a fluororesin film. But,
The conventional agricultural coating material as described above is blended with a small amount of an ultraviolet absorber for the purpose of improving weather resistance, and therefore, the conventional agricultural coating material generally blocks ultraviolet rays in sunlight to some extent. Although it has properties, the fluororesin film is originally excellent in weather resistance, and since it is not particularly necessary to add a weather resistance improver such as an ultraviolet absorber, the agricultural coating material made of the fluororesin film is exposed to sunlight. Ultraviolet rays inside are also transmitted. Therefore, the same kind of greenhouse crops that have been cultivated in a conventional manner have been developed so that they can be cultivated in greenhouses that have been covered with an agricultural coating material that blocks some ultraviolet rays. When cultivated in various manners, various problems not found in conventional agricultural covering materials, for example, delay in growth or harvest time, deterioration of harvest quality due to hardening of foliage or fruits, flower color of petals A new problem has arisen, such as thickening or discoloration of.

The fluororesin film is excellent in mechanical strength, transparency, weather resistance and the like, and is most suitable as a base material for agricultural coating materials that can be spread over a long period of time, for example, 10 years or more. The inventors have made earnest studies to solve the above problems of the agricultural coating material made of a fluororesin film. As one means for solving the above problems, it is conceivable to add an ultraviolet absorber to a fluororesin film as in conventional agricultural coating materials, but the fluororesin has a high melt processing temperature, It is practically impossible to incorporate an organic UV absorber as used in agricultural coating materials.

The present inventors have found that the inorganic fine powder, especially cerium oxide (CeO ₂ ), can withstand the melt processing temperature of fluororesin.
As a result of intensive research and development of a fluororesin film that can be used without causing the above problems even for conventional greenhouse cultivation crops,
The present invention has been reached.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of conventional agricultural coating materials, and to achieve durability which has never been known. It is to provide an excellent agricultural coating material.

[0009]

The present invention has been made to solve the above-mentioned problems, and contains at least cerium oxide fine powder and blocks at least 30% of the transmission of ultraviolet rays in the wavelength range of 300 to 330 nm. 400 and 800
It is an object of the present invention to provide a highly durable agricultural coating material made of a fluororesin film having a visible light transmittance of at least 70% in the wavelength range of nm. The fluororesin film used as the agricultural coating material of the present invention has at least 30%, preferably 50% or more, more preferably 70% or more of the ultraviolet ray in the sun rays, which transmits the ultraviolet ray in the wavelength range of at least 300 to 330 nm. % Or more, most preferably 85
% Or more. It is not always necessary to block the transmission of ultraviolet rays having a wavelength longer than 330 nm, but about 35
It is also desirable that the transmission of ultraviolet rays in the wavelength range of 0 nm or less is blocked by at least 40%, preferably 50% or more.

On the other hand, 400 to 800 required for growing crops
Visible light in the wavelength range of nm is desirably transmitted as much as possible, and the transmittance thereof is at least 70%, preferably 80% or more, more preferably 85% or more, and most preferably 88% or more. Here, "400-800 nm
“Visible light transmittance in the wavelength range” is an average transmittance of visible light in the wavelength range.

The fluororesin film exhibiting the light transmission characteristics as described above is prepared, for example, by kneading the fluororesin film with cerium oxide fine powder capable of blocking the transmission of ultraviolet rays in the wavelength range of at least 300 to 330 nm. Alternatively, on at least one side of the fluororesin film,
It can be produced by providing a coating layer containing the cerium oxide fine powder.

The fluororesin used as a substrate in the production of the above film is a (co) polymer obtained from a fluorine-containing monomer, and specifically, for example, polytetrafluoroethylene (PTFE), tetra Fluoroethylene-perfluoroalkyl vinyl ether copolymer (P
FA), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), tetrafluoroethylene-
Hexafluoropropylene-perfluoroalkyl vinyl ether copolymer (EPE), tetrafluoroethylene-ethylene copolymer (ETFE), polychlorotrifluoroethylene (PCTFE), chlorotrifluoroethylene-ethylene copolymer (ECTFE), poly Examples thereof include vinylidene fluoride (PVDF), polyvinyl fluoride (PVF), and a mixture of two or more of these. Above all, ETFE, PCTFE, ECTF
E, PVDF and PVF are preferred, and further ETF
E, PVDF and PVF are preferable, and ETFE is particularly preferably used.

ETFE is mainly composed of ethylene and tetrafluoroethylene (the molar ratio of ethylene / tetrafluoroethylene is generally 40/60 to 60/40),
And if necessary, a small amount (usually 10 mol% or less)
Is a copolymer of the third fluorine-containing comonomer component of. In the present invention, in particular, the ethylene / tetrafluoroethylene content molar ratio is in the range of 40/60 to 60/40, preferably 45/55 to 55/45.

The third component may be, for example, the formula CH _{2
= CH-C n F 2n +} 1 ( wherein, n represents an integer of 2 to 10) perfluoroalkyl vinyl monomer unit represented by _{(e.g., CH 2 = CH-C 4} H 9 or CH ₂ = CH-
Unit derived from C ₆ H ₁₃ ) and CH ₂ ═C (CF
₃ ) CH ₃ , CF ₂ ═C (CF ₃ ) CH ₃ , CH ₂ ═CFC ₅ F
A fluoroolefin such as ₁₀ H can be used, and the former is preferably used. An ethylene-tetrafluoroethylene copolymer having a content of the third component in the range of 0.1 to 10 mol%, preferably 0.3 to 5 mol% is preferably used. This ethylene-tetrafluoroethylene-based copolymer is known per se and can be produced, for example, by the method described in JP-B-59-50163, and is commercially available from Asahi Glass Co., Ltd. under the name "Aflon". It is also possible to use a commercially available product under the trade name "COP".

On the other hand, as the cerium oxide which can be kneaded into the above-mentioned fluororesin, both of two kinds having oxidation numbers of 3 and 4 can be used, and the latter CeO ₂ is preferably used.

The particle size of these cerium oxide fine powders is not particularly limited as long as it can impart the above-mentioned optical properties to the film, but generally, the average particle size is 1,0.
The thickness is 00 nm or less, preferably 500 nm or less, more preferably 100 nm or less, and particularly preferably 50 nm or less.

The amount of the cerium oxide fine powder blended in the film varies depending on the resin used and the film thickness, but is generally 0.01 to 10% by weight, preferably 0.1. The amount may be in the range of 1 to 5% by weight, more preferably 0.5 to 2% by weight.

The film can be molded from the fluororesin containing the cerium oxide fine powder by a method known per se, such as an extrusion molding method and an inflation molding method. The thickness of the obtained film is generally 10
˜1000 μm, preferably 30 to 200 μm, particularly preferably 50 to 100 μm.

Further, the fluororesin film having the above-mentioned light-transmitting property is a coating solution comprising the above-mentioned cerium oxide fine powder and a resin binder on the surface of a preformed fluororesin film having the above-mentioned thickness. It can also be produced by coating.

At this time, it is desirable that the surface of the fluororesin film is subjected to a surface activation treatment for the purpose of uniformly applying the coating liquid to the surface of the fluororesin film and improving the adhesion of the coating layer.

As a method of such surface activation treatment,
Examples of the method include corona discharge treatment, sputter etching treatment, sodium treatment, and sandblast treatment.

In corona discharge treatment, discharge is performed between a needle-shaped or knife-edge electrode and a counter electrode, and a sample is placed between them to perform treatment, and oxygen such as aldehydes, acids, alcohol peroxides, ketones and ethers is placed on the surface of the film. Is a process for generating a functional group containing.

The sodium treatment is a treatment of immersing the film in a liquid ammonia solution of an alkali metal such as metallic sodium, which eliminates CF ₂ bonds from the surface, and CH,
This is a process of generating a C-O bond.

In the sputter etching treatment, a sample is put between electrodes under low-pressure glow discharge, and a large number of fine projections are formed on the film by the impact of positive ions generated by the glow discharge. The sandblast treatment is a method of spraying fine sand on the film surface to form a large number of fine irregularities on the surface.

Among these surface activation treatments, corona discharge treatment is preferable in terms of adhesion to coating, workability, safety, cost and the like.

Examples of the resin binder that can be used in the coating liquid include acrylic resins, vinyl acetate resins, fluororesins, and mixtures thereof. In some cases, hydrophilic polymers such as polyvinyl alcohol and polyvinylpyrrolidone. In addition to -SO ₄ , -SO ₃ H, -COO
_{H, -CN, - (OCH 2} CH 2) a general polymer having a hydrophilic functional group such as may be used in combination.

If necessary, the coating liquid may include, for example, sorbitan fatty acid ester, sorbitol fatty acid ester, diglycerin fatty acid ester, glycerin fatty acid ester, sorbitan fatty acid dibasic acid ester, sorbitol fatty acid dibasic acid ester diglycerin fatty acid diester. A surfactant such as a basic acid ester, a glycerin fatty acid dibasic acid ester, or a compound obtained by adding an alkylene oxide such as ethylene oxide or propylene oxide to these may be added.

Each of the components described above is dissolved or dispersed in, for example, water, alcohol, ketone, ester or ether solvent to prepare a coating solution, and the film surface is coated. As a coating method, for example, a generally known method such as brush coating, dip coating, gravure coating or spray coating can be used.

The concentration of the cerium oxide fine powder in the coating solution varies depending on the coating film thickness, the type of resin binder used, etc., but in general, the content of the cerium oxide fine powder in the formed coating layer is 0.5-0.5. 95% by weight, preferably 1 to 50% by weight, more preferably 3 to
It is desirable to set it within the range of 30% by weight.

The thickness of the coating layer is not strictly limited as long as the obtained film exhibits the above-mentioned light transmission characteristics, but it is generally 1 to 100 μm.
Preferably 2 to 50 μm, more preferably 5 to 20 μm
It can be within the range of m.

The fluororesin film produced as described above and having the above-mentioned light-transmitting properties has the characteristics that the film has as a covering material for agriculture even when it is spread outdoors for a long period of 10 years or more. Can be maintained almost unchanged, and can be applied to various crops improved for greenhouse cultivation without causing the above-mentioned problems, and is a greenhouse covering material instead of glass. Can be widely used as

According to the present invention, there is also provided a useful cultivation method characterized by cultivating a useful crop in a greenhouse covered with the above-mentioned agricultural coating material made of a fluororesin film. To be done.

Here, "useful crops" include agricultural and horticultural and forestry crops useful in human life, and specific examples are as follows. (1) Agricultural and horticultural crops Food crops: rice, wheat, corn, soybean, sweet potato, potato

Garden crops: Fruit trees Apples, pears, oysters, peaches, plums, grapes, loquats, figs, blueberries, pomegranates, lemons, mandarins, etc. Fruit vegetables Cucumbers, watermelons, tomatoes, strawberries, pumpkins,
Melon, eggplant, pea, okra, bell pepper root vegetable carrot, burdock, taro, ginger, lotus root, wasabi, quai, rakkyo leaf vegetable Chinese cabbage, green onion, garlic, onion, kanran, seri, spinach, perilla, butterbur, celery, leek, parsley , Honeywort, asparagus, udo flowers First- and second-year plants Morning glory, cosmos, Iceland poppy, aster, yellow sultan, snapdragon,
Calendula, Stock, Pansy, Sunflower, Benidium, Dimorphoseca, Safflower, White lace flower, Cornflower, Eustoma grandiflorum, Rhodanse herbaceous grass, Oriental orchid, Gypsophila, carnation, gerbera, sycamore, chrysanthemum, oyster grass, starch, peony root, peony root Grass lilies, gladiolus, iris, anemone,
Color, Narcissus, Freesia, Ranunculus, Hyacinth Flower Tree Acacia, Azalea, Rose, New Sailan, Satsuki, Crape myrtle, Ginkgo, Senryo, Cycad, Camellia, Sasanqua, Eucalyptus Greenhouse Plant Orchid, Cyclamen

Industrial crops ・ ・ ・ Oil crops rapeseed, sesame sugar crops sugar cane, sugar beet fiber crops cotton, hemp starch crops konjak medicinal crops peppermint, poppy favorite crop cheya, tobacco, hops paper-based crops Kozo, mitsumata dye crop eye flavor Crop geranium sap crop sumac

Forage crops ・ ・ ・ Forage crops Orchardgrass, red clover, white clover Feed fertilizer trees Breadfruits, alder trees Green manure crops Astragalus, horse mackerel

(2) Forestry trees: coniferous trees Sugi, cypress, pine evergreen broad-leaved tree Aoki, yamde deciduous broad-leaved oak, beech

Among these crops, the crops to which the agricultural coating material of the present invention can be applied particularly advantageously are horticultural crops.
Fruit vegetables, root vegetables, leaf vegetables, flowers, root-root plants, flowering trees and greenhouse plants in the above classification are preferable, and further fruit vegetables,
Flowers, host root grasses and flowering trees are preferable, and fruit vegetables and flowering trees are most preferable.

Examples of fruit vegetables that are preferably used include cucumber, watermelon, tomato, strawberry, melon and pepper. Cucumber, melon and tomato are particularly preferable, and root vegetables include carrot and ginger. Preferable leaf vegetables are Chinese cabbage, leek, celery and honeywort.

[0040] Furthermore, flowers and flowers which are preferably used include stocks and eustoma, and as root-root plants, oriental orchids, gypsophila, carnations, gerberas, chrysanthemums and starches, particularly carnations, gerberas and chrysanthemums. Preferably, as the bulbous grass,
Lilies and iris are preferable, and roses are preferable as the flowering tree.

By cultivating these useful crops in a greenhouse covered with the agricultural coating material of the present invention, various cultivation effects which cannot be obtained by the conventional agricultural coating materials are obtained, as shown in Examples below. be able to. The summary is as follows.

Cultivation management becomes extremely easy as compared with the case of using the conventional covering material for agriculture, so that the farmer can obtain a stable harvest without failing in cultivation. Since it becomes possible to harvest a large amount of high-quality crops as compared with the case of using the conventional agricultural covering material, it is possible to obtain high profit.

EXAMPLES The present invention will be described in more detail below with reference to examples. Production Example of Film Production Example A (Comparative Example) An autoclave having an internal volume of 10 liters was charged with 3.46 kg of trichloromonofluoromethane, 6.52 kg of trichlorotrifluoroethane, and 2.38 g of t-butylperoxyisobutyrate. then tetrafluoroethylene 1226G, ethylene 82 g, and perfluorobutyl ethylene _{(CH 2 = CH-C 4} F 9) is charged with 26 g. The reaction temperature is kept at 65 ° C. while thoroughly stirring this mixture.
To hold the copolymerization reaction.

During the progress of the copolymerization reaction, a mixed gas having a molar ratio of tetrafluoroethylene / ethylene / perfluorobutylethylene of 53 / 46.3 / 0.7 was introduced into the system to adjust the polymerization pressure to 15.0 kg / cm ^2. Hold on. 460 after 5 hours
g of white copolymer was obtained (hereinafter referred to as Resin No. 1). The copolymer had a C ₂ F ₄ / C ₂ H ₄ / CHC ₄ F ₉ content molar ratio of 53 / 46.3 / 0.7, a flow start temperature of 267 ° C., and a thermal decomposition start temperature of 360 ° C. Met.

The ethylene-tetrafluoroethylene copolymer (hereinafter sometimes abbreviated as "ETFE") obtained above was extruded at a resin temperature of 320 ° C. to produce a film No. 1 having a thickness of 60 μm.

Production Example B (Comparative Example) 67 parts by weight of polyvinyl chloride (degree of polymerization: 1300), 25 parts by weight of dioctyl phthalate (plasticizer), 5 parts by weight of tricresyl phosphate (plasticizer), large amount of epoxidation. Soybean oil (plasticizer) 3 parts by weight, barium ricinoleate (stabilizer)
0.8 parts by weight, zinc stearate (stabilizer) 0.5 parts by weight, dibutyltin malate (stabilizer) 0.3 parts by weight, sorbitan monopalmitate (surfactant) 0.6 parts by weight,
And 5 parts by weight of 2-hydroxy-4′-methoxybenzophenone (ultraviolet absorber) were mixed, and the mixture was melt extruded at 200 ° C. by an extruder to obtain a film No. 4 having a thickness of 60 μm.

Production Example C (Example) Except that 1.5 wt% of cerium oxide (CeO ₂ ) having an average particle size of 15 nm was added to the ETFE obtained in Production Example A.
A film No. 2 having a thickness of 60 μm was obtained in the same manner as in Production Example A.

Production Example D (Example) One surface of the film No. 1 produced in Production Example A was subjected to a discharge current of 10 A, a discharge voltage of 120 V and a line speed of 13 m /
Corona discharge treatment was performed under the condition of min. Polyvinyl alcohol 5 on silica sol (silica solid content 8%) on treated surface
wt% and 5 wt% CeO _{2 with an} average particle size of 30 nm were added and diluted 100-fold with ethanol to give 15 g.
The film No. 3 was obtained by coating so as to give a film No. 3 / m ² .

Characteristic Evaluation of Film 1. Transparency As a conventional agricultural coating material, a soft vinyl chloride resin film [trade name: Noviace, manufactured by Mitsubishi Kasei Vinyl Co., Ltd., 100 μm], polyester film [trade name] : Six Light, Taiyo Kogyo Co., Ltd. 175μ
m], polycarbonate resin plate [Product name: Iupilon,
Mitsubishi Gas Chemical Co., Ltd., 1,000 μm], and acrylic resin plate [trade name: acrylic panel, Mitsubishi Rayon Co., Ltd.]
1,700 μm], and the film Nos. 1 to 4 obtained in the film manufacturing example were placed on the outdoor exposure table having a slope of 45 ° facing the south side in Uozu City, Toyama Prefecture. . Four years after the exposure, the agricultural coating material was collected and the total light average transmittance of visible light in the wavelength range of 400 to 800 nm was measured by a spectrophotometer. The results are shown in Table 1.

[0050]

[Table 1]

As is apparent from Table 1, the film No. 4 containing a large amount of conventionally used soft vinyl chloride resin film, polyester film, polycarbonate resin plate, acrylic resin plate and ultraviolet absorber is used.
All had a light transmittance of 50% or less after 4 years of exposure, and could not be used as agricultural coating materials. On the other hand, a film N made of fluororesin
In o.1 to 3, the transparency hardly deteriorates even after the exposure,
The transparency was almost the same as before exposure.

2. Impact resistance The evaluation method was as follows: assuming that a piece of wood flew and collided due to a typhoon, 300 g of pebbles were placed at a height of 50 cm from film Nos. 2 to 3 and sheet glass [Asahi Glass Co., Ltd.]. 3 m / m]
It was decided to drop each on top and check if they would be damaged.

As a result, the plate glass was finely broken, while the film Nos. 2 to 3 were not broken and were completely intact. From this result, the plate glass is
It is assumed that they will be easily damaged by hail and flying objects caused by typhoons. As a result, the useful crops in the house where the flat glass is spread are likely to suffer catastrophic damage. From the above test, the conventional agricultural coating materials that satisfy the transparency and impact resistance,
It was found that it was not present except for the fluororesin film.

Cultivation Example of Useful Crop (1) Cultivation Example of Tomato Film Nos. 1 to 4 obtained in the film production example were spread in a house (frontage: 10 m, depth: 20 m).

Cultivation-1 Seed of tomato (variety: Momotaro) was sown on August 31,
Raised seedlings. On October 5, young seedlings in which the first flower cluster had 2-3 flowers bloomed and were uniformly grown were planted in each house so that the distance between the plants was 50 cm. The amount of fertilizer applied was as shown in Table 2, and the irrigation was controlled for about 10 days after planting so that the young seedlings were so conservative that they did not grow too much. Cultivation temperature is 28 ° C in the morning and 25 in the afternoon.
The temperature and the night temperature were controlled to be 5 ° C. Therefore, warm air was heated by the heater during the low temperature period.

[0056]

[Table 2]

The harvest was carried out from December 12th to May 30th of the following year. The results of the yield investigation are shown in Table 3.

Here, the survey items and the evaluation method are shown below. Yield: An index based on 100 as the total weight of the harvest in the house in which the film No. 4 is spread. The same was calculated for the other cultivation examples below.

[0059]

[Table 3]

Under the film No. 1, the growth of tomato was delayed, the foliage and fruits were hard, and the whole strain was downsized. As a result, the harvest time was later than that of the houses that spread the other films. Further, the balance between the color of the outer skin of the tomato fruit and the color of the jelly portion in the fruit is unbalanced, and the fruit is still green (immature), but the outer skin shows a color as if it was ripe.

Under the film No. 4, the inside of the house was humid and the tomato strain grew too vigorously, resulting in a poor yield. In addition, the strain softens as a whole and the color of the foliage and fruit becomes slightly pale,
It seems that the frequency of disease increased as a result.

Cultivation-2 Based on the result of Cultivation-1, cultivation was changed in the following year, and the cultivation was changed. The house in which the film Nos. 2 and 3 were spread was subjected to the same management conditions as in cultivation-1. In the house where the film No. 1 was expanded, fertilizer application increased by 10%,
The total irrigation volume increased by 10 to 15%, and the night temperature was 1 ° C.
The house was kept at a high level, and each time the direct sunlight from the sun became strong, the roof of the house was covered with 50% light-shielding black ginseng.

In the house where the film No. 4 is spread,
Fertilizer application was reduced by 15%, irrigation was conserved at about 20%, night temperature was set at 1 ° C lower, cultivation was carried out, and defoliation was always carried out so that the plant could be exposed to sunlight as much as possible.

As described above, in the house in which the film Nos. 1 and 4 are spread, the time spent for the farmer's management work is about 1.5 to 2 times that of the film Nos. In the No. 1 house, it was necessary to constantly check the intensity of the sun's rays, which hindered other agricultural work. The cultivation results are shown in Table 4.

[0065]

[Table 4]

As is clear from Table 4, the film No. 1
In the house where 4 and 4 were expanded, the yield increased from the previous year and it was almost the same as the film No. 2, but it did not reach the film No. 3 and the quality was the film Nos. 2 to 3.
It didn't match.

From the cultivation results for the above two years, the film N
By spreading Nos. 2 to 3, the tomato cultivation management becomes extremely easy as compared with the conventionally used film Nos. 1 and 4, and the cultivation management is stable without failing in cultivation. I was able to get a harvest. Moreover, the profitability of the harvested tomatoes was extremely high because of the excellent quality of the tomatoes.

(2) Example of Rose Cultivation On December 15, a rose seedling (variety: curl red) was planted in a house (width 20 m, depth 50 m) in which the film No. 1 was spread so that the distance between the plants was 40 cm. Cultivation is carried out while maintaining the temperature inside the house at 16 ° C or higher, and the rose is harvested in 5
It was carried out from 25th to 30th November. The results are shown in Table 5.

[0069]

[Table 5]

Here, the harvest amount is an index when the total number of roses harvested in the house in which the film No. 4 is spread is 100. As is clear from Table 5, a large number of striped black spots were generated on the petals of the rose in the house in which the film No. 1 was spread, and these could not be sold as products.

As a countermeasure against this, a black frosted cloth that shields 50% of the light rays was covered on the ceiling of the house each time the sun rays became strong, and the roses were sunshine-controlled so that they were not directly exposed to strong light. However, if the frequency of use of ginseng is increased and the sunlight dose is controlled, the rose flower color becomes lighter and the so-called color blur phenomenon occurs. Has dropped.

Further, the flower color of the rose in the house where the film No. 4 was spread was lightened and there was a problem as a product. In addition, the fact that the inside of the house has a high humidity taste is also considered to be the cause of the lightening. With such high humidity, it is considered that the trees tended to be soft and the disease resistance and pest resistance were also reduced. For this control. Pesticide was sprayed, but this pesticide trace further reduced the products.

On the other hand, the growth of roses in the house in which the film Nos. 2 and 3 are spread is promoted, and the flowering time is N.
The flower color became 3 to 4 days earlier than that of No. 1 and became a very bright crimson color.

As described above, in the house in which the film Nos. 2 and 3 are spread, the cultivation management is extremely easy as compared with the house in which the film Nos. 1 and 4 are spread, and the farmer fails to grow roses. It has become possible not only to obtain a stable harvest, but also to obtain a large amount of high quality roses, which has made it possible to obtain high profits.

(3) Cultivation example of eustoma and gerbera Eustoma seeds (variety: Domino pastel) were sown on July 15 and young seedlings were planted in each house on September 27 to continue cultivation 1 Harvest was carried out from the 10th of the month to the 5th of March. The results of this cultivation are shown in Table 6.

[0076]

[Table 6]

Here, the amount of harvest is 1 based on the total number of lisianthus harvested in the house in which the film No. 4 is spread.
It is an index when 00 is set. As is clear from Table 6,
Many black spots appeared on the petals of eustoma in the house where the film No. 1 was spread, and it became impossible to sell it as a product.

As a countermeasure against this, the ginseng used in Cultivation Comparative Example 7 was used in the same manner as Cultivation Comparative Example 7. When black ginseng was used in a large amount, black stains were reduced, but the flower color was changed. The quality has deteriorated due to lightening.

Further, in the house in which the film No. 4 was spread, the flower color became pale, which also caused a problem in the commercial property. On the other hand, in the houses in which the film Nos. 2 and 3 were spread, many eustoma with vivid flower colors were harvested. In addition, in Gerbera (variety: Smoke World), the same cultivation result as that of Eustoma grandiflorum was obtained.

[Procedure amendment]

[Submission date] December 14, 1994

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Brief description of the drawing

[Correction method] Added

[Correction content]

[Brief description of drawings]

FIG. 1 is a film No. It is the wavelength-specific total light transmittance curve figure of 1-4.

[Explanation of Signs] No. Comparative film No. 1 by ETFE 2 Film of the present invention with cerium oxide added No. No. 3 film of the present invention coated with cerium oxide. 4 Comparative film made of polyvinyl chloride

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location C08J 5/18 CEW 7/06 Z C08L 27/18 LGB

Claims (7)

[Claims] 1. Fluorine containing at least cerium oxide fine powder, blocking at least 30% of ultraviolet rays in the wavelength range of 300 to 330 nm and transmitting at least 70% of visible light in the wavelength range of 400 to 800 nm. Agricultural coating material with excellent durability made of resin film. 2. The coating material according to claim 1, wherein the fluororesin film has, on at least one surface thereof, a coating layer containing cerium oxide fine powder having an ability to block transmission of ultraviolet rays in a wavelength range of at least 300 to 330 nm. . 3. The coating material according to claim 1, wherein the film contains 0.01 to 10% by weight of cerium oxide fine powder. 4. The coating material according to claim 2, wherein the coating layer contains 0.5 to 95% by weight of cerium oxide fine powder. 5. The fluororesin film has a molar ratio of 40 /
Ethylene and tetrafluoroethylene in the range of 60 to 60/40, and if necessary, further 10 mol% or less of C ₄
The coating material according to claim 1, which is an ethylene / tetrafluoroethylene-based copolymer obtained by copolymerizing -C ₁₂ perfluoroalkylvinyl monomer. 6. A greenhouse covered with the coating material according to claim 1. 7. A method for cultivating a useful crop, which comprises cultivating a useful crop in a greenhouse covered with the covering material according to claim 1.