JPH0229294B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for drying seed nets, that is, seaweed nets after raising seedlings, on land. A method for drying seed nets that reduces the number of dead cells in buds, allows excellent growth of seaweed even in the cultivation stage after thawing, and increases yield and/or improves the quality of seaweed such as softness and gloss, and the method Regarding covering materials used for. The production methods involved in seaweed cultivation, especially the method of drying seed nets, depend on classic fishing methods that deal with changeable weather, so there are many factors that are influenced by the weather.
This is a major problem for seaweed producers. The general seaweed cultivation process involves collecting fruit spores from aged seaweed from January to March every year, and
From March to October, the filamentous bodies are cultured in flasks and the bacteria are inoculated onto oyster shells, etc. In early October, seeds of chlospores generated from filamentous sporangia in shells are seeded into web cracks (seaweed webs) in coastal waters. From early to late October, seaweed shell spores germinate in the 5-10 layers of mesh cracks, and the young buds continue to grow until they reach 1-3 cm leaf length. The seaweed net obtained through this process is called a seed net. In the past, it was often the case that full-scale aquaculture was carried out as is, but due to recent increases in the demand and production of seaweed, fishing grounds have been expanded to offshore floating type, and the seeds used for netting or relining have been expanded. To make the nets, the seed nets are hauled onto land, and are left to dry in the sun from early morning until mid-morning. The water content of the leaves immediately after sun drying is 20-40%. Thereafter, each dried seed net is sealed in a polyethylene bag, placed in a refrigerator, and stored frozen at a low temperature of -15 to 20 degrees Celsius.
This method allows storage of seed nets for 3 to 4 months. Thereafter, from late October to early March, the seed nets are removed from time to time, thawed in seawater, and then cultured and harvested at the fishing grounds. Plucking is usually 12 to 1
Twice a month in April, once a month from February to March, 10~
The nori leaves that have grown to 15 cm are harvested. After seedling seedlings have been raised for approximately 20 days from early October in the above-mentioned method of net drying, the seed nets are removed from the sea in the early morning on a clear or cloudy day, and placed directly under the sun for 4 to 5 hours in the morning at an outdoor net drying area. They were dried either by exposing them to the sun or by hanging day nets in a limited area under the eaves. With this conventional solar drying method, the drying condition of the seed net is greatly affected by changes in the weather, and especially in sunny weather, if the drying process is delayed and the sun drying continues until the afternoon, the lobule (larval buds) The cells were damaged and many dead cells appeared in the form of white spots. The reality is that if there are many such dead cells in the leaf, the growth of the leaf will be significantly inhibited during the subsequent main cultivation process, and the quality of the seaweed will also deteriorate. Furthermore, rainy weather is not suitable for conventional drying, so drying work is rarely carried out. Furthermore, drying under the eaves is extremely inefficient for processing large quantities of seed nets.
At present, this method alone is far from meeting the demand for dry seed nets. Moreover, a simple method for drying seed nets that is superior to the sun drying method has not yet been found, and in order to meet the increased demand for seed nets for seaweed cultivators, it is necessary to prevent the generation of dead cells while producing high quality seed nets. It was hoped that a method would be developed to dry a large amount of water at once. In the process of drying seed nets, the present inventors used seed net drying racks (approximately 2 m in height x 18 to 20 m in length x approximately 5 m in opening) used in conventional solar drying to dry seeds in the current agricultural industry, such as vegetables. It is placed in a pipe house or a steel frame house that is widely used for facility cultivation, and the light quality conditions of those houses are set to a light quality atmosphere in which light in the wavelength range of at least 340 nm and below is substantially suppressed. By drying the seed net, that is, the seaweed net after raising seedlings, to the desired moisture level under these light conditions, we can produce seaweed seedlings that are less damaged than conventional sun-dried seaweed seedlings, and in particular have an extremely small number of dead cells. It has been found that it not only promotes growth on the farm after thawing, but also improves both yield and quality. The first feature of the present invention is at least the time when the growing of seaweed seedlings is completed (the time when the growth of young seaweed buds is completed), preferably the time when healthy lobules of 1 to 5 cm in length are uniformly grown in the seaweed net. Thereafter, the seed net is preferably dried under a specific light atmosphere for 4 to 5 hours on sunny days, and for 5 to 6 hours on cloudy days. The seaweed that can be applied in the present invention refers to those of the subphylum Rhodophyta of the phylum Algae, class Rhodophyceae, subclass Primitive Rhodophyceae, order Apophyllales, family Apophyllidae, and genus Acanthophyta. Within the genus Porphyra, there are the subgenus Hitomeri, subgenus Futatasuboshia, and subgenus Futaea.
The subgenus Hitoeamanori includes Black Nori, Maruva Amanori, Tsukusia amanori, Oniamanori, Maruba Asakusanori, Yabrea amanori, Utatsunori, Ichimatsunori, Chigara Amanori, Benten Amanori, Anaamanori, Satsukinori, Mesowakea Amanori, Asakusanori, Kayabenori, Susabinori, Kosujinori, and Utsuburi Nori. , Matsuba amanori and Chishimaronori, etc. The subgenus Futatasuboshyamori includes Macrea spp., Oriental spp., and Sunago spp., and the subgenus Futaea spp. The method of the present invention can be applied to any type of seaweed of the genus Porphyra, but preferred are, for example, laver of the genus Porphyra, laver of the genus Porphyra, laver of the same name, laver of the same name, and laver of the genus Utsupurinol. Drying of the seed net according to the method of the present invention is carried out under a light atmosphere in which light in the wavelength range of at least 380 nm and below is substantially suppressed. In this specification, the term "optical atmosphere in which light in the wavelength range of xnm and below is substantially suppressed" preferably means a light quality atmosphere in which light in the wavelength range of xnm and below is completely absent. Although it refers to the atmosphere, it also means that there is no problem even if light in the wavelength range is present in a small amount that does not adversely affect the drying of the present invention. Therefore, when drying under sunlight irradiation, the light quality is such that the transmission of light in the wavelength range in sunlight is blocked by at least 70%, preferably 80% or more, and more preferably 90 to 100%. It is desirable to dry. Furthermore, "substantially transmitting" light in the wavelength range of 380 nm and above means that it does not matter whether the light in the wavelength range is substantially transmitted or the transmission is substantially suppressed. has an average transmittance of light in the wavelength range of 5 to 70%, preferably
It is preferable to keep it within the range of 20 to 70%, more preferably 30 to 60%. Therefore, apart from the limitation of using the above-mentioned specific light quality atmosphere, the drying of the seed net according to the present invention can be carried out by:
No special seed net drying conditions are required, and the drying process can be carried out according to conventional seed net drying methods and conditions. The typical seaweed cultivation process to which the present invention is applied is (1) Collection of fruit spores from aged seaweed (1 to 3
(2) Cultivation of filamentous bodies in flasks, inoculation of fungal cells into oyster shells, etc. (3) Seeding of chlospores generated from sporangia of filamentous bodies in shells into web cracks (October) (4) Raising seedlings from the germination of schistospores to young shoots (nurturing of young shoots: early to late October) (5) Drying of the seed net on land (in the morning of late October, the water content of the leaf body (20 to 40%) (dried under the light quality conditions of the present invention) (6) Frozen storage of seed nets (-15 to 20°C, storage for a maximum of 3 to 4 months) (7) After thawing in seawater, storage at the fishing ground Main cultivation and harvesting (late October to March) can be mentioned. According to the present invention, a coating material for drying seed nets having the above-mentioned light transmission properties is provided. As the coating material of the present invention, there are no particular restrictions on the material, etc., and any type of coating material can be used as long as it has the above-mentioned light transmission properties. Such a covering material can usually consist of an inorganic or organic film, plate, or other molded body. For example, inorganic films or plates typically include glass plates mixed with dyes or pigments (e.g. emerald green), glass plates coated with or laminated with synthetic resin films containing ultraviolet absorbers as shown below, etc. As the organic film or plate, a synthetic resin film or plate coated with or containing an ultraviolet absorber is particularly suitable. In addition to the thermoplastic resins described below, thermosetting resins such as melamine resins, phenolic resins, epoxy resins, silicone resins, urea resins, alkyd resins, and allyl phthalate resins can also be used as resins that can be used for this molding. be able to. However, in the present invention, a synthetic resin film or plate containing an ultraviolet absorber is particularly suitable as the covering material, and this synthetic resin film or plate will be explained in more detail below. The transparent film or plate that can be used in the present invention can be produced, for example, by blending a suitable ultraviolet absorber with a normal film-forming thermoplastic resin and molding the mixture into a film or plate. Examples of usable film-forming thermoplastic synthetic resins include polyvinyl chloride, polyvinylidene chloride, polyethylene, polypropylene, polystyrene, polyester, polyamide, polycarbonate, polymethyl methacrylate, polyacrylate, polyvinyl acetate, polyvinyl alcohol,
Futus-containing resin, cellulose resin, ABS resin, etc.
It also includes copolymers or blends containing these polymers as the main component (preferably 50% by weight or more), particularly polyvinyl chloride, polyethylene, polypropylene,
Polyesters, cellulosic resins and polystyrene are preferred. In addition, an ultraviolet absorber that is blended into a synthetic resin such as the one described above and has the ability to substantially suppress the transmission of light with a wavelength of at least 380 nm or less should be used in combination with the ultraviolet absorbing ability of the ultraviolet absorber and the synthetic resin used. They can be appropriately selected and used from a wide range of types in consideration of compatibility and the like. Examples of usable ultraviolet absorbers include the following. Hydroquinone series: Hydroquinone, hydroquinone disalicylate Salicylic acid series: Phenyl salicylate, paraoctylphenyl salicylate Benzophenone series: 2-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-n-
Octoxybenzophenone, 2-hydroxy-
4-methoxy-2-carboxybenzophenone, 2,4-dihydroxybenzophenone,
2,2'-dihydroxy-4,4'-dimethoxybenzophenone, 2-hydroxy-4-benzoyloxybenzophenone, 2,2'-hydroxy-4-methoxybenzophenone, 2-hydroxy-4-methoxy -5-sulfonebenzophenone, 2,2',4,4'-tetrahydroxybenzophenone, 2,2'-hydroxy-4,4'-dimethoxy-5-sodium sulfobenzophenone, 4-dodecyloxy -2-hydroxybenzophenone, 2-hydroxy-5-chlorobenzophenone benzotriazole series: 2-(2'-hydroxy-
5′-methylphenyl)benzotriazole, 2
-(2'-Hydroxy-5'-methylphenyl)-
5-butoxycarbonylbenzotriazole,
2-(2′-hydroxy-5′-methylphenyl)
-5,6-dichlorobenzotriazole, 2-
(2′-hydroxy-5′-methylphenyl)-5
-Ethylsulfonebenzotriazole, 2-
(2′-hydroxy-5′-tert-butylphenyl)
-5-chlorobenzotriazole, 2-(2'-
Hydroxy-5′-tert-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′-ethoxycarbonylphenyl)benzotriazole, 2-(2′-hydroxy-3′-methyl-5′-tert-butylphenyl)benzotriazole, 2-(2′-hydroxy-3′) ,5′-di-tert-butylphenyl)-5
-Chlor-benzotriazole, 2-(2'-hydroxy-5'-methoxyphenyl)benzotriazole, 2-(2'-hydroxy-5'-phenylphenyl)-5-chlorobenzotriazole, 2-(2'- Hydroxy-5'-cyclohexylphenyl)benzotriazole, butoxycarbonylbenzotriazole, 2-(2'-hydroxy-3',5'-dichlorophenyl)benzotriazole, 2-(2'-hydroxy-4',5'-
dichloro)benzotriazole, 2-(2'-hydroxy-3',5'-dimethylphenyl)-5-
Ethylsulfonebenzotriazole, 2-
(2′-hydroxy-5′-phenyl phenyl)benzotriazole, 2-(2′-hydroxy-
4′-octoxyphenyl)benzotriazole, 2-(2′-hydroxy-5-methoxyphenyl)-5-methylbenzotriazole, 2-
(2′-hydroxy-5′-methylphenyl)-5
-Ethoxycarbonylbenzotriazole, 2
-(2'-acetoxy-5'-methylphenyl)benzotriazole, 2-(2'-hydroxy-
3′,5′-ditertyabutylphenyl)-5-
Chlorobenzotriazole, 2-(2'-hydroxy-3-tert-butyl-5'-methylphenyl)
-5-chlorobenzotriazole, 2-(2'-
Hydroxy-3'-tert-butyl-5'-methylphenyl)-5,6-dichlorobenzotriazole, 2-(2'-hydroxy-3'5'-di-tert-
butylphenyl)-4,5-dichlorobenzotriazole. Among these ultraviolet absorbers, benzophenone-based and benzotriazole-based ones are preferred, and among the benzophenone-based ones, 2,3'-dihydroxy-4,4'-dimethoxybenzophenone,
2,2'-dihydroxy-4-methoxybenzophenone and 2,2',4,4'-tetrahydroxybenzophenone: In benzotriazole series, 2-
(2'-hydroxy-5'-methylphenyl)benzotriazole, 2-(2'-hydroxy-5'-methylphenyl)-5,6-dichlorobenzotriazole, 2-(2'-hydroxy-3'-methyl-
5′-tert-butylphenyl)benzotriazole,
2-(2′-hydroxy-3′,5′-di-tert-butylphenyl)-5-chlorobenzotriazole and 2-(2′-hydroxy-5′-phenylphenyl)-5-chlorobenzotriazole, 2-
(2'-Hydroxy-3',5'-ditertyabutylphenyl)-5-chlorobenzotriazole, 2-
(2′-hydroxy-5′-octoxyphenyl)benzotriazole, 2-(2′-hydroxy-3′-
tert-butyl-5'-methylphenyl)-5-chlorobenzotriazole, 2-(2'-hydroxy-
3′-tert-butyl-5′-methylphenyl)-5,
6-dichlorobenzotriazole and the like are effective. Particularly suitable UV absorbers have the formula or In the formula, R ₁ and R ₂ are the same or different and each represents a lower alkyl group or an aryl group (especially a phenyl group), and in particular R ₁ is preferably a branched lower alkyl group or a phenyl group having C ₅ or less. It is a benzotriazole derivative represented by the following, where R ₃ represents an alkyl group of C ₆ or more, especially C ₈ to C ₁₀ , and X is a hydrogen atom or a halogen atom, especially a chlorine atom. The amount of the ultraviolet absorber as described above can be varied widely depending on the type of ultraviolet absorber, the type of synthetic resin used, the thickness of the film or plate, etc. In order to substantially prevent the transmission of ultraviolet rays of 15≦AB≦600, preferably 20≦AB≦400, the amount of ultraviolet absorber added and the thickness of the resulting film or plate should be determined according to the following formula: In the formula, A represents the amount of ultraviolet absorber (PHR) and B is the thickness (μ) of the film or plate. It has been found that it is particularly preferable that the following relationship is satisfied: . Here, PHR means parts by weight per 100 parts by weight of synthetic resin. In addition, the amount (A) of the UV absorber varies depending on the type of synthetic resin and UV absorber, but in general
0.001~5PHR, especially for film 0.1~5.0PHR
A range of is suitable. It also makes the resulting film substantially white,
Examples of white pigments that can be blended into the synthetic resin to achieve a predetermined light transmittance include titanium white, lithopone, lead white, zinc white, carbonates such as calcium carbonate, magnesium carbonate, and barium carbonate, and sulfuric acid. Calcium, sulfates such as magnesium sulfate, metal aluminum powder, etc. may be mentioned, and these white pigments may be combined with a black pigment such as carbon black in an amount that does not substantially impair the whiteness of the white pigment. good. Furthermore, a white dye may be used if necessary. The amount of white pigment to be blended depends on the type of pigment and the thickness of the coating material, but in general, synthetic resin
0.1 to 10 parts by weight per 100 parts by weight, preferably 0.3 to 10 parts by weight
A range of 5 parts by weight is preferred. In addition to ultraviolet absorbers and white to black pigments, the synthetic resin used in the present invention may also contain other conventional resin additives, such as plasticizers, lubricants, antioxidants, light stabilizers, A small amount of antistatic agent, moisturizer, heat stabilizer, etc. can also be included. Furthermore, the synthetic resin film or plate used in the present invention, or the molded article as described above, can be produced by various methods known per se, such as a calender method, a melt extrusion method such as an inflation method, a press method, a solution casting method, and an injection method. It can be manufactured using a molding method or the like. Further, in order to prevent deterioration of the physical properties of the film, it may be coated with another resin or laminated with another film. The film or plate formed in this way is
The thickness can vary over a wide range depending on the intended use, but generally a range of 15 to 5000 microns, particularly 20 to 300 microns, is suitable for the purposes of the present invention. The film or plate may include, if necessary,
It can also be used by laminating it on other synthetic resin films, sheets, glass, etc. for reinforcement purposes.
Furthermore, the synthetic resin film or plate formed as described above, particularly the film, may be reinforced with reinforcing fibers such as glass fibers, wire mesh, or reticulated fiber structures. In addition, in order to prevent the transparency of the coating material of the present invention from decreasing due to adhesion of dust, etc., as necessary,
The surface may be treated with a chemical or may be laminated or coated with other synthetic resin containing such a chemical. When forming the specific optical quality atmosphere using the coating material according to the present invention, it is not necessary to completely seal the seed net against ultraviolet rays in the specific wavelength range, and it is not necessary to completely seal the seed net against ultraviolet rays in the specific wavelength range. On the other hand, the coating may be applied so that the irradiation of light in the wavelength range that may be present in the irradiation light (for example, direct sunlight) is substantially suppressed. Therefore, when drying the seed net under sunlight, the light that is irradiated onto the seed net is usually considered to be of two types: direct sunlight and indirect scattered light, but in the method of the present invention, at least The seed net can be protected from this direct sunlight. The covering material of the present invention can be made by directly reusing the steel frames, pipe houses, tunnels, and other aggregates used for facility cultivation of vegetables and fruit trees. When drying seed nets, in order to control temperature and provide ventilation, raise the hem to prevent direct sunlight from entering, use skylight ventilation, shoulder ventilation on the opposite side of the sun, or open the gables of the greenhouse. can do. Thus, according to the method of the invention, the seed net is dried in a house or tunnel covered with the film. According to the method of the present invention described above, the occurrence and deterioration of dead cells in young buds due to direct sunlight, which until now had no effective preventive measures and was thought to occur to some extent, can be virtually completely prevented. can do. In addition, according to the method of the present invention, the growth of seaweed at this farm after thawing is good, so an increase in yield is expected.
In addition, since there are almost no dead cells, there are advantages such as the possibility of harvesting well-shaped, high-quality leaves with a strong dark color. As described above, the method of the present invention greatly contributes to seaweed cultivators in drying seaweed seed nets. Next, the present invention will be further explained by examples. Reference Example Preparation of films of the present invention and comparative examples (1) 100 parts by weight of polyvinyl chloride, 45 parts by weight of dioctyl phthalate (plasticizer), 1.5 parts by weight of dibutyltin maleate (thermal stabilizer), zinc stearate (thermal stabilizer) ) 1.0 parts by weight, stearic acid (lubricant) 0.1 parts by weight, sorbitan monolaurate (dropless agent) 1.0 parts by weight, and 2-(2' hydroxy-
3′,5′ ditertiarybutylphenol)-5-chlorobenzotriazole (ultraviolet absorber) 1.5
parts by weight and 2.5 parts by weight of titanium oxide (R-820) were thoroughly mixed with each other, and the mixture was melt-extruded at 200°C using an extruder to obtain a white film with a thickness of 0.1 m/m. This film will be referred to hereinafter as Film No. 1 and will be used for coating in the Examples below. In addition, by melt extrusion in the same manner with the above formulation completely excluding only the inner titanium oxide component, the thickness
A colorless transparent film of 0.1 m/m was obtained. This film will be referred to as Film No. 2 hereinafter and will be used for coating in Comparative Examples described later. In addition, the ultraviolet absorber of the above No. 2 film composition was replaced with a benzophenone-based ultraviolet absorber.
Seesorb101 was replaced with 1.2 parts by weight and mixed, and a film was formed in the same manner to obtain a colorless transparent film with a thickness of 0.1 m/m. This film will be referred to as Film No. 3 from now on.
and is used for coating in the comparative example. (2) For comparison, as a general agricultural covering material,
Commercially available polyvinyl chloride film (thickness
0.1 m/m; "Noviace" manufactured by Mitsubishi Monsanto Kasei Co., Ltd.) was prepared. This film will be referred to as film No. 4 hereinafter. The wavelength-specific light transmittance curves of the above films No. 1 to 4 are shown in FIG. 1 of the accompanying drawings. Example 1, Comparative Examples 1 to 4 A house as shown in FIG. 2 was installed as a seed net drying facility. A pipe house with an opening of 8m, a length of 24m, and a height of approximately 4m, with a net shelf for conventional solar drying, a width of 5m, and a length of 5m.
It has enough space to store 2.5m. The roof of each greenhouse was coated with films No. 1 to 4 as covering materials.The aggregates used in these greenhouses were those that have been widely used for facility cultivation of vegetables, fruit trees, etc., and were used as they were. The shaded areas in the figure were covered with coating materials of films Nos. 1 to 4, respectively, on the roof. Seed nets were sown using a conventional method from October 3rd to October 10th, and then young shoots were grown for 30 days from October 11th, and then subjected to a drying test. 11
Drying tests were conducted on three sunny and cloudy days, the 12th, 13th, and 14th of the month, and the results are shown in Table 1. After that, each of these seed nets was placed in a polyethylene bag, sealed, and frozen for 70 days at a controlled temperature of -15℃ using conventional methods.
The fish were thawed on the same day, and cultured using the conventional prop culture method and floating culture method for 30 days until February 14th. During the cultivation period, the seaweed was harvested twice every 15 days, and the cultivation yield, quality, grade, etc. of the obtained seaweed were measured and the results are shown in Table 1.

[Table] Floating culture method test method Method for determining dead cell rate: After drying out, 25 sheets of seaweed were randomly cut from the seed nets of the example plot and the comparative sample plot, and examined under a microscope. , measure the number of dead cells in 250 fields. Dead cell rate = number of dead cells in 250 fields/total number of measured cells in 250 fields x 100 Cultivation yield index of harvested seaweed. Comparative example 2 (sun-sun conventional method) cultured and harvested 6-sun 3-minute x 5-sun 8-sized seaweed sheets compared to the number of harvested sheets in other test plots when the number of seaweed harvested is 100 Judgment Sensory test conducted by inspectors, number of respondents who answered that it was an excellent product by 10 inspectors Judgment of black appearance of seaweed Sensory test conducted by inspectors, number of responses that answered that it was an excellent product in terms of black color. Gloss Judgment Sensory test conducted by inspectors, number of respondents who answered that the product was good in terms of gloss based on 10 inspectors. Comprehensive judgment of quality The number of respondents who answered that the product was of excellent quality based on the sensory test conducted by the inspector and the overall judgment by 10 inspectors.

[Brief explanation of drawings]

FIG. 1 shows wavelength-specific light transmission curves of films No. 1 to No. 4 used in Example 1 and Comparative Examples 1 to 3.
Figure 2 shows the pipe house used in Examples 1 to 3 and Comparative Example 1, where h is the height of 4.0 m, a is the frontage of 8 m,
b is 24m deep.

Claims (1)

[Scope of Claims] 1. Light that substantially suppresses the transmission of light in the wavelength range of at least 380 nm and below, and suppresses the transmission of light in the near-ultraviolet, visible, and infrared regions of 380 nm or more to 5 to 70%. A method for drying seed nets, characterized by drying the seed nets in a quality atmosphere. 2 An inorganic or organic film or plate that substantially suppresses the transmission of light in the wavelength range of at least 380 nm and below, and suppresses the transmission of light in the near-ultraviolet, visible, and infrared regions of 380 nm or more to 5 to 70%. A covering material used for drying seed nets, characterized by comprising: 3. The coating material according to claim 2, wherein the organic film or plate is a synthetic resin film or plate containing an ultraviolet absorber. 4 The ultraviolet absorber has the formula or [In the formula, R ₁ and R ₂ are the same or different and each represents a lower alkyl group or an aryl group (especially a phenyl group), and R ₁ is particularly preferably a branched lower alkyl group or a phenyl group, and R 1 is preferably a branched lower alkyl group or a phenyl group; ₃ is
represents an alkyl group of C ₆ or more, especially C ₈ to C ₁₀ ,
is a hydrogen atom or a halogen atom (particularly a chlorine atom)] The coating material according to claim 3, which is a benzotriazole derivative. 5. The covering material according to claim 3, wherein the synthetic resin film or plate is made of polyvinyl chloride.