JPH0489383A - Fertilizer coated with photo-degradable film - Google Patents

Abstract

PURPOSE:To form a fertilizer coated with a photo-degradable film which is rapidly degraded after the fertilizer is put on soil and the effective component leaches out of the fertilizer by coating granular fertilizer with a copolymer contg. vinyl ketone groups. CONSTITUTION:This fertilizer coated with a photo-degradable film is a granular fertilizer coated with a film contg. a vinyl ketone copolymer, preferably an olefin-vinyl ketone copolymer and/or a vinylidene chloride-vinyl ketone copolymer as an effective component. One or more among ethylene, propylene and butene are used as the olefin. The vinyl ketone may be methyl vinyl ketone, ethyl vinyl ketone or propyl vinyl ketone. The pref. amt. of the carbonyl of the vinyl ketone in the vinyl ketone copolymer is 0.01-10wt.%.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to granular fertilizers coated with a coating that disintegrates by light or oxidation. More specifically, the present invention relates to the fertilizer coated with a film containing a vinyl ketone copolymer as an active ingredient.

In the product of the present invention, the rate of elution of fertilizer components can be adjusted by controlling the conditions for adjusting the coating.

[Prior art and its problems] In recent years, coated granular fertilizers have been developed that encapsulate granular fertilizers to adjust the elution rate of fertilizer-effective ingredients, and are gradually being put into practical use. The coating methods for coated granular fertilizers can be roughly divided into the following two types. That is, (1) a relatively thick coating using a low-molecular-weight material such as sulfur, wax, or low-molecular-weight olefin, and (2) a relatively thin coating using a high-molecular material such as polyolefin. However, as for the coated granular fertilizer obtained, the latter, that is, one coated with a polymeric material, is superior in terms of greater controllability of elution rate and less damage to the coating when handling the granular fertilizer. However, on the other hand, the coating process with polymeric materials is technically not easy and requires a considerable amount of time to decompose the coating residue remaining in the soil after the product (coated granular fertilizer) is applied to the soil. There are problems such as the need for

The present inventors have previously developed a technology for coating granular fertilizer with a polymeric material and adjusting the elution rate of fertilizer-effective ingredients, and have filed a patent application for the technology. For example, in Japanese Patent Publication No. 5099.858, a coating technique using polyolefin resin hot liquid and a technology for controlling elution rate using a surfactant were introduced in Japanese Patent Publication No. 60-37,
No. 074 disclosed a more advanced elution rate control technique using a polyolefin resin, an ethylene vinyl acetate copolymer, and a surfactant in combination. In addition, special public service 1986-3,0
No. 40 and JP-A No. 55-1,672 disclose the elution of fertilizing ingredients by using a polyolefin resin composition similar to the above-mentioned one further mixed and dispersed with inorganic powder such as talc or sulfur powder. In addition to adjusting the speed,
A technique has been disclosed that can promote the disintegration or decomposition of residual capsules or coating residues after use (application to soil) of granular fertilizers.

Furthermore, JP-A No. 63-17285 discloses a coated fertilizer coated with a photodegradable film containing a polyolefin resin and a rubber resin as active ingredients, and JP-A No. 63-17286 discloses a coated fertilizer coated with a photodegradable film containing a polyolefin resin and a rubber resin as active ingredients. A coated fertilizer is coated with a photo-degradable film having the main resin component, and JP-A No. 63-25288 covers it with a photo-degradable film having a polyolefin resin and ethylene vinyl acetate/carbon oxide copolymer as the active ingredients. The technology for coated fertilizer was disclosed.

The inventors' technology for a series of coated fertilizers is to use polyolefin resin or polyvinylidene chloride resin as the basic resin and blend resin such as ethylene vinyl acetate copolymer or elastomer to adjust the elution rate; Technology to control the temperature dependence of elution rate by dispersing minerals such as talc, technology to improve the disintegration of coatings by dispersing sulfur and starch in these, and resins that naturally disintegrate into basic resins and combination resins. have been used to increase the degree of collapse.

These combinations result in various degrees of disintegration. Covered F! ! I1)! The functions required of the disintegrating membrane of the fertilizer are to be stable during storage and transportation before use, and during elution after fertilization, maintain elution control function as designed, and promptly disintegrate and decompose after elution is complete. However, it is difficult to achieve both stability and disintegration, as increasing disintegration leads to a lack of storage stability.

For example, the combination of the above-mentioned known resins that has the best disintegrability is the combination of ethylene-carbon oxide copolymer and ethylene-vinyl acetate-carbon oxide copolymer, but in this case, ammonia-based When coated with fertilizer (for example, urea, ammonium phosphorus, or compound fertilizer), there are problems with storage stability, such as accelerated changes in the film when stored at high temperatures even in direct sunlight.

[Problems to be Solved by the Invention] In view of the technical problems of the above-mentioned prior art related to the functions of coated granular fertilizers, the present inventors have developed a coating with a high level that satisfies all of the elution control function, storage stability, and film disintegration properties. After repeated search and research on molecular materials, the present invention was completed by discovering that a copolymer containing a new vinyl ketone group has excellent properties for the purpose of imparting photodegradability.

As is clear from the above description, the object of the present invention is to provide a coated granular fertilizer whose coated portion quickly disintegrates after it is applied to soil and the fertilizing ingredients are eluted.

[Means to solve the problem] The present invention has the following configurations (1) to (9).

(1) A photodegradable film-coated fertilizer coated with a film containing a vinyl ketone copolymer as an active ingredient.

(2) The photodegradable film-coated fertilizer according to item (1), which is coated with a film containing as an active ingredient at least one of an olefin and vinyl ketone copolymer and a vinylidene chloride and vinyl ketone copolymer.

(3) At least one of olefin polymer and vinylidene chloride polymer and at least one of thretin/vinyl ketone copolymer, vinyl acrylate ketone, methyl methacrylate/vinyl ketone, methyl methacrylate vinyl ketone polymer, and ethylene vinyl acetate/vinyl ketone. The photodegradable film-coated fertilizer according to item (1) above, which is coated with a film containing an active ingredient.

(4) the above (1) containing as an active ingredient a vinyl ketone copolymer in which the vinyl ketone is methyl vinyl ketone, ethyl vinyl ketone, propyl vinyl ketone, isopropyl vinyl ketone, butyl vinyl ketone, methyl isopropyl ketone, or ethyl isopropyl ketone; f21.
(The photodegradable film-coated fertilizer described in item 31.

(5) Carbonyl content of vinyl ketone is 0.01-10
The above-mentioned (1), (2), and (3) coated with a film containing as an active ingredient a vinyl ketone copolymer position of % by weight.
), the photodegradable film-coated fertilizer described in item (4).

(6) The photodegradable film-coated fertilizer according to item (2), which is coated with a film containing as an active ingredient a copolymer of vinyl ketone and at least one of ethylene, propylene, and butene.

(7) The photodegradable film-coated fertilizer according to item (3) above, which is coated with a film containing a polymer consisting of one or more of ethylene, propylene, and butene.

(8) The photodegradable film-coated fertilizer described in items [1] to (7) above, wherein a poorly water-soluble or water-insoluble powder is mixed in the film.

(9) The water-soluble or water-insoluble powder is one or more selected from talc, calcium carbonate, clay, diatomaceous earth, silica, silica salts, metal oxides, grains, or starch powders. The photodegradable film-coated fertilizer according to item (8) above.

The structure and effects of the present invention will be explained in detail below.

The vinyl ketone copolymer used as an essential active ingredient in the present invention is basically an unsaturated vinylidene monomer f
R1) R1c=cR, fR41 is polymerized with vinyl ketone R'Cf.CHl *COR as a minor component, and it has a linear ketone structure of [R'c (COR) ], and Ro is hydrogen or It is a C1-C6 alkyl group, and R is a C3-C9 alkyl or alkylene group.

Examples of unsaturated vinylidene monomers include olefins such as ethylene, propylene, butene, and vinyl monomers represented by the structural formula CH,=CiRIX.

Here, R is hydrogen, halogen or an alkyl group, and X is a carboxyl group, halogen group, ester group or nitrile group.

For example, a copolymer using ethylene as an unsaturated vinylidene monomer and methyl vinyl ketone monomer as the vinyl ketone has the following general structure.

The vinyl ketone copolymer used in the present invention has a carbonyl content of vinyl ketone groups of 0.01 to 10% by weight.
belongs to.

Carbonyl group is 0. If the percentage by weight is ungrooved, the degree of photodegradability is low, and if it exceeds 10% by weight, it is unstable to light and is not practical. There are no particular restrictions on the arrangement of the monomers, but the photodegradation function is due to the presence of carbonyl groups, which are preferably present uniformly within the molecule, so random polymerization products are desirable.

In the present invention, the vinyl ketone copolymer can be used alone or in combination with a mixture of different types of vinyl ketone copolymers, and can also be used in combination with a polymer other than the vinyl ketone copolymer.

The preferred mixing ratio is not specified, but if the vinyl ketone copolymer contains a large amount of vinyl ketone monomer, for example 70% by weight or more, other non-degradable polymers may be added, for example 50% by weight. Even if a large amount is added, the film has sufficient photodegradability.

As described above, the type and blending ratio of the vinyl ketone copolymer are selected depending on the target degree of disintegration, but usually the vinyl ketone copolymer is selected in a range of 5 to 100% by weight.

In the present invention, olefin polymers and/or copolymers, vinylidene chloride polymers and/or copolymers are used as basic polymers. This is essential as it becomes the basis for coating operations and elution rate adjustment.

Therefore, in the present invention, when an olefin or a copolymer of vinylidene chloride and vinyl ketone is used, it can be used alone without being used in combination with other polymers, or in combination with a mixture thereof.

Needless to say, this case is most desirable for the present invention because it can be mixed with other types of polymers within the range blended in the present invention.

As the polymer to be blended, various vinyl ketone copolymers not containing olefins or vinylidene chloride monomers can be used in combination, and in this case, the photodegradability of the coating is particularly preferable.

The olefin and vinyl ketone copolymer used in the present invention was obtained by copolymerizing olefins such as ethylene, propylene, and butene, either singly or as a mixture, and vinyl ketone.

As the vinyl ketone, methyl vinyl ketone, ethyl vinyl ketone, propyl vinyl ketone, and methyl isopropyl ketone are preferred. In particular, ethylene-methyl vinyl ketone, ethylene-methyl isopropyl vinyl ketone, and ethylene ethyl ketone are effective in the present invention, but the present invention is not limited thereto. The vinylidene chloride and vinyl ketone copolymer used in the present invention is a copolymer of denylidene chloride monomer or a mixture of vinylidene chloride and vinyl chloride monomer (vinyl chloride MAX, 30% by weight) and vinyl ketone, and is a copolymer of vinyl ketone and olefin. The same vinyl ketone monomers as in the case of are used.

Vinyl monomers used in the vinyl ketone copolymer other than olefin or vinylidene chloride monomers include styrene, vinyl chloride, acrylic acid, methacrylic acid and esters thereof, and vinyl acetate.

Furthermore, there are copolymers of three or more of these vinyl monomers, ethylene, and vinyl ketones, such as ethylene vinyl acetate, vinyl ketone copolymers, ethylene, methacrylic acid, and vinyl ketone copolymers, but the present invention is not limited to these. do not have.

Vinyl ketones used here include methyl vinyl ketone, ethyl vinyl ketone, propyl vinyl ketone,
In addition to isopropyl vinyl ketone and butyl vinyl ketone,
Methyl isopropyl ketone, ethyl isopropyl ketone, and the like can also be used, but are not limited thereto.

The vinyl ketone copolymer of the present invention other than the copolymer of olefin or vinylidene chloride monomer and vinyl ketone is used in combination with a copolymer of olefin or vinylidene chloride monomer and vinyl ketone, or is used in combination with an olefin polymer or a copolymer of olefin and monoxide. Carbon copolymers, vinylidene chloride copolymers, such as polyethylene, polypropylene, polybutene, ethylene, propylene copolymers, ethylene-propylene-butene copolymers, ethylene-carbon oxide copolymers, vinylidene chloride polymers and vinylidene chloride copolymers. Vinyl chloride copolymer and 7
They are used together in a range of 0% by weight or less.

If it exceeds 70% by weight, tackiness during coating operation (Block 1
There are problems with ρ) and elution function, and the function as a covering fertilizer is not sufficient.

Although not an essential requirement for the present invention, various polymers other than those described above can be used in combination in the present invention.

For example, thermoplastics such as polystyrene, polymethyl methacrylate ethylene-vinyl acetate copolymer, ethylene-acrylic acid copolymer, natural rubber, polyisoprene, polybutadiene, styrene-butadiene block copolymer, styrene isoprene block copolymer, etc. Thermoplastic resins such as elastomers are effective.

In addition to the above-mentioned polymer, the products of the present invention also include coated fertilizers that are coated with a film containing powder dispersed therein. In principle, any substance can be used as the powder as long as it is sparingly soluble or insoluble in water.

However, it is desirable that the particle size is less than the thickness of the desired coating, and when using it, it is necessary to disperse it as uniformly as possible in the organic solvent of the above resin or resin composition.

If the powder is difficult to disperse in the above resin or resin composition, the surface of the powder may be treated with a silicone resin or the like.
Covered F! l) It is necessary to impart lipophilicity to the powder, or to impart appropriate dispersibility to the powder during the above-mentioned dispersion treatment.

Preferred powders used as coating materials for the coated fertilizer of the present invention include, for example, talc, calcium carbonate, clay,
Inorganic materials such as diatomaceous earth, silica and its salts, metal oxides, and sulfur, or organic materials such as starch powder can be used.

Addition of these powders tends to promote the disintegration of the film and generally promotes elution, so it is necessary to use them in various ways depending on the purpose.

When designing the coating composition of the photodegradable film-coated fertilizer of the present invention, it is necessary to select the coating composition by considering the balance between disintegration properties, storage stability, and elution controllability.

The photodegradability of the coating resin composition is controlled by the amount of carbonyl group copolymerized as a vinyl ketone monomer, and the amount of 〉C=0 in the vinyl ketone copolymer or the resin composition containing the same must be controlled. This makes it possible to control the photodegradability of the film.

When increasing the proportion of resin other than the vinyl ketone copolymer, the proportion of C=0 groups in the vinyl ketone copolymer for blending can be adjusted to improve the photodegradability of the entire film. can be adjusted. Regarding the storage stability of photodegradable film-coated fertilizers, in general, attempts to improve the disintegration properties tend to result in poor storage stability. In general, the product of the present invention also has a significantly stronger culm disintegration property as the number of vinyl ketones increases, but the deterioration in storage stability is small in comparison to the increase in the number of vinyl ketones. The vinylidene monomer can be selected as a partner for the vinyl ketone copolymer, making it possible to combine various desired copolymers. It is a preferable material for imparting and maintaining functions such as sex.

For example, in the case of a copolymer of ethylene and methyl vinyl ketone, a coating with a higher decomposition property is obtained than when coated with an ethylene-carbon oxide copolymer, which also has photodegradable properties. It has advantages such as not requiring the use of disintegration aids.

In addition, even when a combination resin such as ethylene vinyl acetate methyl vinyl ketone copolymer is used, the storage stability of a photodegradable film coated with a copolymer in which degradable carbon monoxide is introduced in a linear chain is similarly improved. Excellent quality.

In this case, there is a particularly large difference in storage stability when coated with ammonia-based fertilizer.

In order to control the elution of fertilizer components inside particles from the photodegradable film-coated fertilizer of the present invention, the composition of the resin is adjusted. Among the vinyl ketone copolymers that are essential as a coating component of the fertilizer of the present invention, copolymers with olefin and vinylidene chloride have the effect of slowing down elution; , a copolymer of ethylene-acrylic acid and vinyl ketone, etc. have the effect of promoting elution.

The desired elution rate will vary depending on the type of internal fertilizer, grain size, and coverage rate, so it can be obtained by trial lead production (finally by adjusting the type and proportion of the copolymer). Since the products of the present invention can be selected from a wide variety of products, there are many advantages in that products with various physical properties can be selected.

Furthermore, since many resins other than the vinyl ketone copolymer essential to the invention can be used in combination with the present invention, there is a great advantage that most general-purpose resins can be used, especially in the case of commercial production.

The product of this invention does not require special consideration in the fertilization method when used as a general slow-release fertilizer (lasting for several months), but it is especially suitable for products that are guaranteed to continue to be effective over a long period of time due to its photodegradable properties. Full-layer fertilization is recommended. These are exposed to the surface layer during cultivation etc. after use, undergo photodegradation, become low in molecular weight, and are finally completely decomposed by microorganisms.

Since it will not suffer from photodeterioration if it is stored protected from light, it is effective to add known ultraviolet absorbers, antioxidants, etc., especially considering that it will be left in the hot sun for a long period of time.

In this case, it is desirable to select and use a material that has physical properties that allow it to be removed from the film by bleed or elution during fertilization, since this will not affect the photodegradability of the eluate.

Various powders used as optional components in the product of the present invention also affect the function of the present invention. Generally, as the amount of powder increases, the elasticity decreases, the dissolution rate increases, and there is a tendency for the composition to disintegrate easily.

These degrees vary widely depending on the type of powder, particle size, and surface properties (affinity), so it is necessary to appropriately select the type of resin, degree of polymerization, blending ratio, etc. to create a composition that meets the purpose. There is.

Since the product of the present invention is in the form of coating the surface of a granular fertilizer, the fertilizer to be used is a granular product, but its type is not limited.

That is, molds of known chemical fertilizers such as ammonium sulfate, ammonium chloride, ammonium nitrate, urea, potassium chloride, potassium nitrate, sodium nitrate, ammonia phosphate, potassium phosphate, and lime phosphate, and chemical fertilizers that combine two or more of these types. It's fertilizer.

The method for producing the coated granular fertilizer of the present invention, that is, the method for coating the granular fertilizer, is carried out by the aforementioned known method (Japanese Patent Publication No. 5099.858,
60-37.074). In this method, an organic solvent solution of the above-mentioned coating material composition is sprayed onto the granular fertilizer in a transferred or fluidized state by means such as spraying to coat the surface thereof, and at the same time, the coated material is exposed to high-speed hot air. This is a method in which the organic solvent on the surface of the coating is instantly evaporated to dryness by treatment with a stream. In this case, it is most preferable to fluidize the granular fertilizer using a spouted bed.

In this case, part or all of the medium powder of the coating material according to the present invention is mixed with jet hot air, dispersed, and the above-mentioned coating operation is performed, so that the powder is included in the coating formed on the surface of the granular fertilizer. A known method by the present inventors for dispersing the body (Japanese Patent Publication No. 6)
0.102) can also be adopted. This method is suitable when using powder that is difficult to uniformly disperse in the organic solvent solution of the above-mentioned coating material composition.

The present invention will be explained below with reference to Examples.

Example 200 Manufacturing Example of Fertilizer of the Present Invention Figure 1 shows the jet encapsulation device used in this example. ] is a jet tower with a tower diameter of 250 mm and a height of 200 mm.
, air jet diameter 50mm, cone angle 50℃, fertilizer input port 2,
It has an exhaust gas outlet 3. The jet air is sent from the floor 10 and reaches the jet tower via an orifice flow meter 9 and a heat exchanger 8, but the flow rate is controlled by the flow meter and the temperature is controlled by the heat exchanger.
The exhaust gas is led out of the tower from the discharge outlet 3. The granular fertilizer used in the encapsulation process is introduced through the fertilizer inlet while passing a predetermined amount of hot air to form a jet stream. The hot air temperature is detected by thermometers T1, the temperature of particles during encapsulation is detected by T2, and the exhaust temperature is detected by T3. When T3 reaches a predetermined temperature, the encapsulating liquid is sprayed in a spray form toward the jet stream through the fluid nozzle 4. The encapsulation liquid is stirred in a liquid tank 1), and when powder is used, the powder is uniformly dispersed.From there, it is sent by a pump 6, but the 1) is sent to the nozzle.
A double pipe is used to allow steam to flow outside to prevent the temperature from dropping below 00℃. When a predetermined encapsulation rate is reached, the blower is stopped and the encapsulated fertilizer is extracted from the extraction lower.

In this example, encapsulation was performed while maintaining the following basic conditions.

Fluid nozzle heat Air flow Heat Air temperature Fertilizer type Fertilizer input volume Encapsulation liquid concentration Encapsulation liquid supply volume Encapsulation time Encapsulation rate (relative to fertilizer) Opening 0.8mm Full condenser type: 4m”7m1n 100℃± 2°C: 5 to 8 mesh granular urea: 10 kg: Solid content 25% (heavy R) 0.5 kg/min: 40 minutes 5.0% To prove customer elution control and capsule disintegration, Table 1 shows Samples of Examples and Comparative Examples of the present invention shown below were produced.

(1) Example of measuring the dissolution rate of the fertilizer of the present invention 10 g of each of the fertilizers of the present invention produced in (2) was crushed in 200 nl water and left to stand at 25°C. After a predetermined period of time, the fertilizer and water are separated and the urea dissolved in the water is determined by quantitative analysis. Add 200 mβ of fresh water to the fertilizer, let it stand at 25°C again, and perform the same analysis after a predetermined period of time. By repeating such operations and graphing the relationship between the cumulative elution rate of urea dissolved in water and the number of days to create an elution rate curve, it is possible to determine the number of days required to reach an 80% dissolution rate.

The 24-hour dissolution rate in water in the elution section of Table 1 is the dissolution rate in water after 24 hours at 25°C in the above dissolution rate measurement, and the number of days for 80% dissolution is the dissolution rate in water in the above dissolution rate measurement. This was determined by creating a curve.

(2) Example of measuring the degree of disintegration of capsules Take 5 g of each of the fertilizers produced in (2), make pinholes with a needle for each particle, and leave to stand in water to completely dissolve the urea inside to form hollow capsules. Dry the hollow capsule and use it as a test sample.

A rectangular polyvinyl chloride resin box measuring 15 cm long, 15 cm wide, and 15 cm high was almost filled with 12 mesh baths of dry sand, and purified hollow capsules were arranged on the surface.
Installed a quartz plate (2mm) to prevent rain from entering and placed it outdoors.
After being left for several months (April to June), the entire amount of sand and capsules were placed in a ■-type mixer with rotating blades and stirred and mixed for 30 minutes. After that, separate the sand and capsules in 107791 boxes, and
The percentage of capsules that did not pass through the O-mesh relative to the sample capsules was determined and shown in Table 1 as the degree of disintegration.

■■、Storability measurement■ 5 kg of the coating material manufactured in ■ is placed in a 200U opaque resin bag (resin bag for filling chemical fertilizers), heat-sealed, arranged on a pallet (for preserving and transporting fertilizer bags), and placed on a waterproof cloth sheet. The samples were covered with water and left outdoors for one year, and the appearance (particularly coloring) and changes in elution (degree of elution into water) were examined and evaluated as follows.

A: No change in appearance or elution: Appearance: Slight yellowing (unnoticeable unless you compare carefully) C: D: E: No change in elution Appearance: Yellow to brown color change No change in elution Appearance: yellow, Appearance: Discoloration to brown Change (acceleration) in elution, but within 10% in relative value Appearance, discoloration to yellow and brown Change in elution (promotion) is significant (more than 10% in relative value) M dyeing >> ＞Dyeing Natsume

[Brief explanation of the drawing]

Figure 1 shows Jet coating used in examples of the present invention The flow sheet of the device is shown. − Below

Claims (9)

[Claims] (1) A photodegradable film-coated fertilizer that is coated with a film containing a vinyl ketone copolymer as an active ingredient. (2) Claim No. (2) coated with a film containing as an active ingredient one or more of olefin-vinyl ketone copolymer and vinylidene chloride-vinyl ketone copolymer.
1) The photodegradable film-coated fertilizer described in item 1). (3) one or more olefin polymers and vinylidene chloride polymers and styrene-vinyl ketone copolymers, acrylic acid-vinyl ketone copolymers, methyl methacrylate-vinyl ketone copolymers, methyl methacrylate-vinyl ketone copolymers, A photodegradable film-coated fertilizer according to claim (1), which is coated with a film containing one or more ethylene vinyl acetate-vinyl ketone copolymers as an active ingredient. (4) Claims containing as an active ingredient a vinyl ketone copolymer in which the vinyl ketone is methyl vinyl ketone, ethyl vinyl ketone, propyl vinyl ketone, isopropyl vinyl ketone, butyl vinyl ketone, methyl isopropyl ketone, or ethyl isopropyl ketone. (
The photodegradable film-coated fertilizer described in items 1), (2), and (3). (5) The photodegradable film coating according to Claims (1), (2), (3), and (4), wherein the vinyl ketone carbonyl content in the vinyl ketone copolymer is 0.01 to 10% by weight. fertilizer. (6) A photodegradable film-coated fertilizer according to claim (2), which is coated with a film containing as an active ingredient a copolymer of vinyl ketone and one or more of ethylene, propylene, and butene. (7) The photodegradable film-coated fertilizer according to claim (3), which is coated with a film containing as an active ingredient a polymer consisting of one or more of ethylene, propylene, and butene. (8) A photodegradable film-coated fertilizer according to claims (1) to (7), which comprises a film mixed with a poorly water-soluble or water-insoluble powder. (9) A patent claim in which the poorly water-soluble or water-insoluble powder is one or more selected from powders of talc, calcium carbonate, clay, diatomaceous earth, silica, silica salts, metal oxides, sulfur, or starch. The photodegradable film-coated fertilizer according to item (8).