JPH09309784A - Oxidative degradation type coated glanular fertilizer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an oxidative degradation type coated granular fertilizer whose coating film can be collapsed due to its change into a porous film and due to its oxidative degradation and which is free from the change of elution, also after preserved, by covering the surface of the granular fertilizer with a coating film containing a specific thermoplastic resin and biodegradable polyester particles as active components. SOLUTION: This oxidative degradation type coated granular fertilizer is obtained by covering the surface of a granular fertilizer with the coating film of a composition comprising a thermoplastic resin containing a substance for accelerating the oxidative degradation reaction of the polymer and biodegradable polyester particles as active components. The substance for accelerating the oxidative degradation of the polymer includes unsaturated fatty acids having C=C unsaturated bonds, unsaturated fatty acid esters, oils, fats, dienic polymers, transition metals and transition metal compounds. The thermoplastic resin includes polyolefins, their copolymers, polyvinylidene chloride and its copolymers. The biodegradable polyester is preferably e.g. poly 3-hydroxy-3-alkylpropionic acid.

Description

Detailed Description of the Invention

[0001]

[0001] The present invention relates to a coated granular fertilizer. More particularly, it relates to a coated granular fertilizer coated with a degradable coating.

[0002]

2. Description of the Related Art As a coated granular fertilizer coated with a disintegrable or degradable coating material, an ethylene / carbon monoxide copolymer (JP-B-2-23516) has heretofore been used.
No.), ethylene / vinyl acetate / carbon monoxide copolymer (Japanese Patent Publication No. 23515/1990) is used as the main coating material, and technology for imparting degradability to capsules has been released. ing. Coated fertilizer by this technology decomposes slowly in the dark state where light does not reach the soil, and decomposes and disintegrates when exposed to the surface layer. Could remain. Furthermore, in order to obtain sufficient decomposability even when light does not reach,
A technique of coating with a biodegradable polyester such as polyesters (Japanese Patent Publication No. 2-23517) is also disclosed. However, it is difficult to secure a stable elution control in the soil of this kind of film because the film undergoes soil decomposition, and the film of polyesters has a high moisture permeability and can only elute very quickly. Furthermore, the material cost is high, and there are many issues before practical use outside the range of economy for application to fertilizer. Examples of long-term elution control technology include a blending method of a biodegradable polyester and a resin having a low water vapor permeability, as disclosed in JP-A-7-61884. However, as disclosed in Japanese Patent Application Laid-Open No. 7-61884, a film obtained by dissolving a biodegradable polyester and a resin having a small water vapor permeability together in a solvent and completely blending it has a small strength as a film, and is manufactured, stored, distributed, It was not able to withstand the load on the coating in each use. On the other hand, a coating in which sulfur is dispersed in a thermoplastic resin (Japanese Patent Publication No. 1-39955) is disclosed. This is a technique in which sulfur in a coating film becomes porous due to sublimation and volatilization after application, which causes a reduction in coating strength and accelerates oxidative decomposition, thereby decomposing the film. This technique can be achieved relatively inexpensively in terms of cost, and is attracting attention as a technique for overcoming the above two types of disadvantages.
However, since the sublimation and volatilization of sulfur starts immediately after production, there is a practical disadvantage that the elution function such as the elution rate and the elution pattern varies depending on the storage period and storage conditions. On the other hand, as a disintegrating film due to the porosity and oxidative decomposition of the film, a film in which an autoxidizing compound and a sugar polymer are dispersed in a resin (JP-A-6-144981) is disclosed. According to this coating, the drawbacks of Japanese Patent Publication No. 1-39995 can be solved, but the obtained coated granular fertilizer does not elute for a certain period of time after application, and only the timed elution type of elution starts after a certain period of time elapses. Therefore, it was not possible to show what is called a linear type elution that starts elution immediately after application. Further, a sugar polymer such as starch easily absorbs moisture in the air, and the absorbed sugar polymer has a problem that the elution of the coated granular fertilizer is not stable. Therefore, in order to make the elution of the product uniform, it was necessary to dry the sugar polymer once and to keep the water content constant at that time. For this reason, when a sugar polymer is used, the production process includes a drying step, and a certain amount of labor and time are required because a certain moisture state cannot be maintained unless handling is strictly performed after drying. there were.

[0003]

As a result of intensive studies conducted by the present inventors in view of the problems of the prior art, surprisingly, a thermoplastic resin containing a substance that accelerates the oxidative decomposition reaction of a polymer is contained. Completed the present invention by recognizing extremely excellent properties in the oxidative decomposition type coated granular fertilizer characterized by coating the surface of the granular fertilizer with a film of a resin and a composition containing biodegradable polyester fine particles as an active ingredient. did. As is clear from the above description, the object of the present invention is a disintegrating film that disintegrates by porosity and oxidative decomposition of the film during use, a drying step is unnecessary in the production process, and elution varies even after storage. It is to provide a coated granular fertilizer coated with a non-stick coating.

[0004]

The present invention has the configurations described in (1) to (11) below. (1) An oxidative decomposition type obtained by coating the surface of a granular fertilizer with a thermoplastic resin containing a substance that accelerates the oxidative decomposition reaction of a polymer and a film of a composition containing biodegradable polyester fine particles as an active ingredient. Coated granular fertilizer. (2) The substance that promotes the oxidative decomposition reaction is an unsaturated fatty acid having a -C = C-unsaturated bond, an unsaturated fatty acid ester,
The oxidative decomposition type coated granular fertilizer according to (1) above, which is one or more kinds selected from fats and oils, diene polymers, transition metals and transition metal compounds. (3) The oxidative decomposition type coated granular fertilizer according to (1), wherein the thermoplastic resin is at least one selected from polyolefins and copolymers thereof, polyvinylidene chloride and copolymers thereof. (4) Polyolefin and its copolymer are polyethylene, polypropylene, ethylene-propylene copolymer,
Ethylene / vinyl acetate copolymer, ethylene / carbon monoxide copolymer, ethylene / vinyl acetate / carbon monoxide copolymer, ethylene / acrylate copolymer, ethylene / methacrylic acid copolymer, rubber resin, polystyrene, The oxidative decomposition type coated granular fertilizer according to (3) above, which is one or more selected from polymethylmethacrylate and the like. (5) The oxidative decomposition type coated granular fertilizer according to (3), wherein the polyvinylidene chloride and its copolymer are polyvinylidene chloride and vinylidene chloride / vinyl chloride copolymer. (6) Polyester having biodegradability is poly-3-hydroxy-3-alkylpropionic acid, poly-2-hydroxy-2-alkylacetic acid, polycaprolactone, or an aliphatic compound represented by the following general formula (1). The oxidative decomposition type coated granular fertilizer according to (1) above, which is polyester.

Embedded image (R ¹ and R ² represent an alkylene group having 2 to 10 carbon atoms.) (7) The above (6), wherein the alkyl group of poly-3-hydroxy-3-alkylpropionic acid is a methyl group or an ethyl group. Oxidative decomposition type coated granular fertilizer. (8) The oxidative decomposition type coated granular fertilizer according to (6), wherein the alkyl group of poly-2-hydroxy-2-alkylacetic acid is hydrogen, a methyl group or an ethyl group. (9) R of the aliphatic polyester represented by the general formula (1)
The oxidative decomposition type coated granular fertilizer according to the above (6), wherein ¹ is an alkylene group having 2 or 4 and / or 4 carbon atoms.

Embedded image (R ¹ and R ² represent an alkylene group having 2 to 10 carbon atoms.) (10) R ^{2 of the} aliphatic polyester represented by the general formula (1) is an alkylene group having 2 or / and 4 carbon atoms. The oxidative decomposition type coated granular fertilizer according to (6) above.

[Chemical 6] (R ¹ and R ² represent an alkylene group having 2 to 10 carbon atoms.) (11) The particle size of the biodegradable polyester fine particles is 0.5 to.
The oxidative decomposition type coated granular fertilizer according to (1) above, which has a range of 100 μm.

The structure of the present invention will be described in detail below. What is effective as a substance that accelerates the oxidative decomposition reaction essential to the present invention (hereinafter referred to as an oxidation promoter) is an organic compound or polymer having a -C = C- unsaturated bond, and as the organic compound, an unsaturated fatty acid is used. , Unsaturated fatty acid esters such as oleic acid, linoleic acid, linolenic acid, arachidonic acid, erucic acid, palmitol acid, ricinoleic acid, eleostearic acid, such as oleic acid, linoleic acid, linolenic acid, arachidonic acid, erucic acid, Palmitol acid, ricinoleic acid, methyl ester such as eleostearic acid, ethyl ester, propyl ester, isobutyl ester, etc., oils and fats, such as linseed oil which is a drying oil, soybean oil, tung oil, sesame seed oil which is a semi-drying oil, rapeseed oil , Cottonseed oil, vegetable oil such as olive oil which is a non-drying oil, camellia oil, castor oil, and whale oil,
Animal oils such as beef tallow, fish oil, and liver oil are listed, and examples of the polymer include diene-based polymers such as polybutadiene, polyisoprene, styrene-butadiene copolymer, styrene-isoprene copolymer, and acnylonitrile-butadiene copolymer. However, the present invention is not limited to these.

Further, other oxidation promoters include transition metals or transition metal compounds, such as Cu, Ag, Zn and C.
Examples include fine powdery metals such as d, Cr, Mo, Mn, Fe, Co, and Ni, metal oxides, metal halides, inorganic acid metal salts, and organic acid metal salts. The transition metal oxide is, for example, an inorganic pigment such as titania (particularly anatase type), chrome oxide green, or cobalt blue. The transition metal halide is, for example, NiCl ₂ , NiBr ₂ ,
CoBr ₃ , FeCl ₂ , FeCl ₃ , CrCl ₂ , C
rCl ₄ , MnCl ₂ , MnCl ₃ , TiCl ₄ , Cu
Cl, ZnCl ₂ or the like, and the inorganic acid transition metal salt is, for example, sulfuric acid, sulfurous acid, nitric acid, nitrous acid, carbonic acid,
Phosphoric acid, phosphorous acid and Zn, Cd, Cr, Mo, Mn, Fe,
Co, Ni, Cu and the like are finely pulverized salts, and organic acid transition metal salts are, for example, organic acids having 1 to 22 carbon atoms, that is, transition metals of saturated, unsaturated, aliphatic carboxylic acids and aromatic carboxylic acids. It is a salt, but is not limited to these. Further, in the present invention, a transition metal complex having a catalytic action may be used.

Among substances having an unsaturated bond of -C = C-, organic compounds having a relatively low molecular weight such as fatty acids, fatty acid esters, and fats and oils are contained in an amount of 0.5-40 by weight of the polymer composition.
%, Preferably 1 to 30% is desirable. Below this range, the effect of promoting the oxidative decomposition of the polymer is insufficient, and above this range, the decomposition of the coating is further promoted, but the strength of the coating is reduced and the coating is not practical. Among substances having an unsaturated bond of -C = C-, those having a high molecular weight such as a diene polymer are added in an amount of 0.5 to 80%, preferably 1 to 70% by weight of the polymer composition. It is desirable to do. As in the case of low molecular weight organic compounds, the oxidation promoting effect is insufficient below this range. In addition, polymers having unsaturated bonds, such as diene polymers, also have a function of accelerating the elution of the coating film. If the amount exceeds this range, the elution will be too fast to obtain a desired elution control.

The transition metal and transition metal compound are contained in an amount of 0.001 to 20%, preferably 0.05 to 20% by weight of the polymer composition.
It is desirable to add 15%. Below this range, the effect of promoting oxidation is insufficient. Further, the addition amount is sufficient within the above range, and even if it is increased beyond the range, no improvement in the effect can be expected. In addition, too much addition is not suitable because heating during production may cause deterioration of the coating. These oxidation promoters are prepared by introducing a sensitive group which is susceptible to oxidative decomposition, such as a -C = C- group, into a polymer film.
The object of the present invention is achieved by any method for introducing a substance having a catalytic action for oxidative decomposition such as a transition metal.

Examples of the thermoplastic resin essential to the present invention include polyolefin and its copolymer, polyvinylidene chloride and its copolymer. Since the biodegradable polyester has strong hydrophilicity and has an action of promoting elution in the coating material, polyolefin and its copolymer, polyvinylidene chloride and its copolymer (hereinafter referred to as the resin) are
It is desirable to use one having a low polarity and a low water vapor permeability. Preferred polyolefins and copolymers thereof in the present invention include polyethylene, polypropylene, ethylene / propylene copolymer, ethylene / vinyl acetate copolymer, ethylene / carbon monoxide copolymer, ethylene / vinyl acetate / carbon monoxide copolymer. Polymers, ethylene / acrylate copolymers, ethylene / methacrylic acid copolymers, rubber-based resins, polystyrene, polymethylmethacrylate, etc. may be mentioned, but any resin may be used as long as it has low water vapor permeability. Can be used. Examples of polyvinylidene chloride and copolymers thereof preferable for the present invention include polyvinylidene chloride and vinylidene chloride / vinyl chloride copolymers. Any of these resins may be used as long as they have a low water vapor permeability like the polyolefin resin.

The biodegradable polyester essential to the present invention is
In-body hydrolyses produced by microorganisms in the soil, in-vivo hydrolases, or other hydrolases present in the soil, or those in which the main chain is cleaved by action such as hydrolysis in normal soil environment . The decomposition rate is not particularly specified, but may be selected according to the purpose of use. However, in the case of capsules of the shape used for current resin-coated fertilizers, it is practical to select from capsules that decompose in soil for a period of several months to 10 years and lose their shape. I think that it is a range. In principle, any polyester having this function can be used, but the biodegradable polyester shown below is a particularly recommended resin material. As a preferred biodegradable polyester material in the present invention, polyester is poly-3-hydroxy-
3-alkylpropionic acid and its copolymer, poly-2-
Hydroxy-2-alkyl acetic acid and its copolymer,
Examples thereof include polycaprolactone and an aliphatic polyester copolymer represented by the following general formula (1).

[0011]

[Chemical 7] (R ¹ and R ² represent an alkylene group having 2 to 10 carbon atoms.)

The poly-3-hydroxy-3-alkylpropionic acid having any composition represented by the general formula (2) can be used in the present invention, and as a more preferable material, poly-3-hydroxy-3-alkylpropionic acid is used. Examples thereof include oxy-3-methylpropionic acid, poly-3-hydroxy-3-ethylpropionic acid, and a copolymer of 3-hydroxy-3-methylpropionic acid and 3-hydrooxy-3-ethylpropionic acid. I can. However, 3-hydroxy-3-methylpropionic acid and 3-hydroxy-
Whether the copolymer with 3-ethylpropionic acid is a random bond or a block bond, the object of the present invention can be achieved.

[0013]

Embedded image (R represents an alkyl group.)

The poly-2-hydroxy-2-alkyl acetic acid having any composition represented by the general formula (3) can be used in the present invention, but poly-2-hydroxy is more preferable material. Acetic acid, poly-2-hydroxy-2-methylacetic acid, poly-2-hydroxy-2
-Ethyl acetic acid, and a copolymer of 2-hydroxyacetic acid and 2-hydroxy-2-methylacetic acid.

[0015]

Embedded image (R represents an alkyl group.)

However, the object of the present invention can be achieved even if the copolymer of 2-hydroxyacetic acid and 2-hydroxy-2-methylacetic acid has a random bond or a block bond. These poly-2-hydroxy-2-alkylacetic acid monomers have three types of optical isomers, L-form, D-form, D and L-form, and any of these may be It can be used in the invention.

The polycaprolactone having the composition represented by the general formula (4) can be used in the present invention regardless of whether R is an alkylene group and Cn = C2 to C5.

[0018]

Embedded image (R represents an alkyl group.)

The aliphatic polyester copolymer represented by the general formula (1) is obtained by a condensation reaction between a glycol having an alkylene group having 2 to 10 carbon atoms and a dicarboxylic acid or its anhydride.

[0020]

Embedded image

R ¹ is a glycol having an alkylene group having 2 to 10 carbon atoms, for example, ethylene glycol, propylene glycol, trimethylene glycol, butanediol 1,3, butanediol 1,4, pentanediol 1,5,3. -Methylpentanediol 1,5, hexanediol 1,6, heptanediol 1,7, octanediol 1,8, nonanediol 1,9, decanediol 1,10, neopentylglycol and mixtures thereof. R ² is an aliphatic dicarboxylic acid having an alkylene group having 2 to 10 carbon atoms or an anhydride thereof, and examples thereof include succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, nonanedicarboxylic acid, Dodecanoic acid, succinic anhydride, glutaric anhydride and mixtures thereof. Of the above glycols and dicarboxylic acids, butanediol 1,4 and succinic acid or their anhydrides, ethylene glycol and succinic acid or their anhydrides, butanediol 1,4 and adipic acid, and combinations of ethylene glycol and adipic acid are raw materials. The cost is low and it can be said that the combination is desirable in the present invention. Although these biodegradable polyesters have greater hygroscopicity than resins with low polarity, such as polyethylene and polypropylene, they are much smaller than starch, so if biodegradable polyesters are used, fine powders can be produced during the production process. It is no longer necessary to provide a drying step in.

The particle size of the biodegradable polyester microparticles of the present invention (hereinafter referred to as the microparticles) is not particularly limited, but since the microparticles have large moisture permeability, the particle diameter is not less than the thickness of the coating film. However, it is preferable that the particle size of the fine particles is equal to or less than the thickness of the coating film, because the dissolution is too early and it becomes difficult to control the dissolution. Also, in order to make it porous and promote degradability,
The particles are preferably fine particles, and the particle diameter of the fine particles is preferably in the range of 0.5 to 100 μm. More preferably, it is in the range of 0.5 to 20 μm. In the present invention, in order to promote the decomposability of the coating film, the amount of the fine particles dispersed may be increased to increase the amount of the formed pores. The amount of the fine particles dispersed is not particularly limited, but when the amount of the fine particles dispersed exceeds 70%, particularly when the fine particles are dispersed in a resin having a small polarity, such as polyethylene, the fine particles easily aggregate with each other. Since the moisture permeability is locally increased, it may be difficult to control the elution of the film, or the film strength may be extremely lowered. Therefore, the dispersion amount of the fine particles is 70% or less, preferably 60% or less, and more preferably It is preferably 50% or less.

Further, in the present invention, a surfactant can be added as long as the film strength and the elution control function are not impaired. Surfactants which can be used in the present invention may be cationic, anionic, amphoteric or nonionic, but the balance between hydrophilicity and hydrophobicity of the surfactant is important. It should be added according to the state of blending of the coating.

The present invention is applicable to granules containing any fertilizer component. For example, water-soluble fertilizers such as ammonium sulfate, salt ammonium, ammonium nitrate, urea, potassium chloride, nitrate potassium, sodium nitrate, ammonium phosphate, potassium phosphate, lime phosphate, and the like, and chelated iron, iron oxide, iron chloride, boric acid, borax, and sulfuric acid. It is particularly effective for fertilizers containing one or more components of water-soluble trace elements such as manganese, manganese chloride, zinc sulfate, copper sulfate, sodium molybdate, and ammonium molybdate. In addition, OMUP (Blackylidene Diurea), IBD
When applied to poorly water-soluble fertilizers such as U (isobutylidene diurea) and oxamide, the effective period of these fertilizers can be extended.

For the purpose of controlling elution and reducing the cost of the coating, a hardly water-soluble or water-insoluble filler may be added to the coating of the present invention. However, the composition of the coating should be determined in consideration of the fact that the addition of a filler affects the strength of the coating, and should be used within a range that does not impair the effects of the present invention. Although it depends on the coating composition, it is recommended that the filler be added at 80% or less of the coating weight. Examples of the inorganic filler include powders of talc, clay, diatomaceous earth, silica, calcium carbonate, zeolite, metal oxide or sulfur, and examples of the organic filler include sugar polymer and its derivative, or crotylidene diurea, isobutylidene. Powders such as diurea and oxamide can be used.

The method for coating the oxidative decomposition type coated granular fertilizer of the present invention is not particularly limited. A solution obtained by dissolving or dispersing the above-mentioned coating material in an organic solvent is sprayed together with a high-speed hot air flow in a spray state on fertilizer particles in a rolling state or a flowing state, and the solvent is instantaneously dried, thereby coating the granular fertilizer of the present invention. Can be obtained. At this time, the fine particles of the present invention do not necessarily have to be in the form of particles in a solvent, and even if they are once dissolved, they may be in the form of fine particles when the film is formed.

[0027]

EXAMPLES The effects of the present invention will be described with reference to the following examples. 1. Production Example of the Fertilizer of the Present Invention FIG. 1 shows a jet encapsulation apparatus used in the production example. 1 is a jet tower having a tower diameter of 250 mm, a height of 2000 mm,
It has a fertilizer inlet 2 and an exhaust gas outlet 3 with a nitrogen gas outlet diameter of 50 mm and a cone angle of 50 degrees. The nitrogen gas for the jet is sent from the blower 10 and reaches the jet tower through the orifice flow meter 9 and the heat exchanger 8. The flow rate is controlled by the flow meter and the temperature is controlled by the heat exchanger. Is derived.
The granular fertilizer used for the encapsulation process is injected from the fertilizer input port 2 while passing a predetermined hot air (N ₂ gas) to form a jet. The hot air temperature is detected by T ₁ , the particle temperature during encapsulation is detected by T ₂ , and the exhaust gas temperature is detected by T ₃ . T ₂
When the temperature reaches a predetermined temperature, the encapsulating liquid is sprayed through the one-fluid nozzle 4 toward the powder particles. The coating liquid is stirred in the liquid tank 11 and, in the case of using powder, is stirred so that the powder is uniformly dispersed in the coating liquid. When the predetermined coverage is reached, the blower is stopped and the coated fertilizer is discharged from the outlet 7. Table 1 shows the composition of the prototype sample.

[0028]

[Table 1]

In this production example, a trial production of a sample was performed while maintaining the following basic conditions. One-fluid nozzle: Opening 0.8 mm Full-con type Hot air flow rate: 4 m ³ / min Hot air temperature: 100 ± 2 ° C Fertilizer type: 6-7 mesh granular urea Fertilizer input amount: 10 kg Test solvent: Perchlorethylene coating liquid concentration : Solid content 5.0 wt% Coating liquid supply rate: 0.3 kg / min Coating rate: 12% * The coating liquid is sent from the pump 5 to the nozzle, but 10
Heat with steam so that the temperature does not drop below 0 ° C.

2. Measurement of Elution Rate Fluctuation after Storage of Fertilizer of the Present Invention 50% elution days were determined for the sample of the present invention immediately after production and the sample of the present invention left outdoors for 2 years, and the elution variation rate was calculated by the following formula. The results are shown in Table 1. * A: 50% elution days of the sample immediately after production B: 50% elution days of the sample after standing outdoors for 2 years Outdoor leaving method: 3 kg of the sample of the present invention is 200 μm thick
m of LDPE resin bag and left outdoors in direct sunlight. 50% elution day measurement method: 10 g of sample of the present invention was
After being immersed in 00 ml of water and allowed to stand at 25 ° C., after a predetermined period of time, it is divided into fertilizer and water, and urea eluted in the water is determined by quantitative analysis. 200 ml of fresh water is added to the fertilizer, and the solution is left to stand at 25 ° C. again. After a predetermined period, the same analysis is performed. By repeating such an operation, the relationship between the total dissolution of urea eluted in water and the number of days is graphed to prepare an elution rate curve, and the number of days until the 50% elution rate is determined.

3. Soil disintegration measurement test A 5 g sample of the present invention is pinhole-formed one by one using a sharp needle, and allowed to stand in water at 30 ° C for 2 weeks to elute urea therein to form an empty capsule. An empty capsule separated from the eluate is put into a resin net and buried in the soil (Minamata Shibukuro, Tertiary soil). After standing for 3 years, the state of the capsule was observed, and for the sample in which the prototype of the capsule was clearly stopped, the entire amount of the capsule was placed in a V-type mixer with rotating blades.
Stir and mix for 0 minutes. After that, it was passed through a 10 mesh sieve, the percentage of the passed capsules to the test capsules was determined, and the disintegration degree is shown in Table-1. Only the traces without stopping the prototype,
Alternatively, if no trace was observed, the above operation was not performed and the disintegration degree was set to 100%.

4. Coating damage test An apparatus for comparing the impact resistance of prototype coated granular fertilizer coatings is shown in Figure 2. The compressed air separately pressurized by the compressor is adjusted by the valve 14, and the inner diameter of the pipe supplied to the pipe 18 through the orifice flow meter 15 is 100 mm, the length L is 5 m, and the wind speed in the pipe is 50 m / sec. Is. The prototype coated granular fertilizer is put into the hopper 16 and supplied into the pipe through the rotary valve 17. The prototype coated granular fertilizer was carried by the wind, and a part of it collided with the collision plate 19 (shown in Fig. 3) provided in the pipe and was stored in the receiver 20, and the remaining prototype coated granular fertilizer was collected. The air removed by the container 21 is discharged into the atmosphere through the exhaust port 22. The prototype coated granular fertilizer stored in the receiver was taken out and used as a damage-treated sample. 10 g each of the sample before and after the damage treatment
The sample after the immersion treatment was immersed in 0 ml of water and left standing at 25 ° C., and only the elution rate in water after 24 hours was measured.

[0033]

EFFECTS OF THE INVENTION The invention of the present invention is required for a disintegrating film, which has good degradability in soil where light cannot reach.
Stable dissolution characteristics that do not change even after long-term storage,
(EN) Provided is a coated granular fertilizer which has a coating strength capable of withstanding loads in production, storage, distribution and use and can be produced by a simple production method.

[Brief description of drawings]

FIG. 1 is a jet encapsulation device used in an embodiment of the present invention.

FIG. 2 Impact resistance test apparatus for coated granular fertilizer of the present invention

FIG. 3 is a collision plate used in the impact resistance test apparatus of the present invention.

[Explanation of symbols]

1: Jet tower 2: Fertilizer inlet 3: Exhaust gas outlet 4: One-fluid nozzle 5: Pump 6: Liquid pipe 7: Fertilizer outlet 8: Heat exchanger 9: Orifice flowmeter 10: Blower 11: Liquid tank 12: Pump 13: Liquid tank 14: Valve 15: Orifice flowmeter 16: Hopper 17: Rotary valve 18: Piping 19: Collision plate 20: Receiver 21: Collector 22: Discharge port 23: Compressed air T ₁ : Thermometer T ₂ : Thermometer T ₃ : Thermometer

Claims (11)

[Claims] 1. An oxidation method comprising coating the surface of a granular fertilizer with a coating film of a thermoplastic resin containing a substance that accelerates the oxidative decomposition reaction of a polymer and a coating film of a composition containing biodegradable polyester fine particles as an active ingredient. Degradable coated granular fertilizer. 2. A substance that promotes an oxidative decomposition reaction is represented by -C =
The oxidative decomposition type coated granule according to claim 1, which is one or more selected from unsaturated fatty acids having C-unsaturated bonds, unsaturated fatty acid esters, fats and oils, diene polymers, transition metals and transition metal compounds. fertilizer. 3. The oxidative decomposition type coated granular fertilizer according to claim 1, wherein the thermoplastic resin is at least one selected from polyolefins and copolymers thereof, polyvinylidene chloride and copolymers thereof. 4. The polyolefin and its copolymer are polyethylene, polypropylene, ethylene / propylene copolymer, ethylene / vinyl acetate copolymer, ethylene / carbon monoxide copolymer, ethylene / vinyl acetate / carbon monoxide copolymer. Combined, ethylene / acrylate copolymer, ethylene /
The oxidative decomposition type coated granular fertilizer according to claim 3, which is one or more selected from a methacrylic acid copolymer, a rubber resin, polystyrene, polymethylmethacrylate and the like. 5. The oxidative decomposition type coated granular fertilizer according to claim 3, wherein the polyvinylidene chloride and the copolymer thereof are polyvinylidene chloride and a vinylidene chloride / vinyl chloride copolymer. 6. The biodegradable polyester is poly 3
-Hydroxy-3-alkylpropionic acid, poly-2
-The oxidative decomposition type coated granular fertilizer according to claim 1, which is a hydroxy-2-alkyl acetic acid, polycaprolactone, and an aliphatic polyester represented by the following general formula (1). Embedded image (R ¹ and R ² represent an alkylene group having 2 to 10 carbon atoms.) 7. The oxidative decomposition type coated granular fertilizer according to claim 6, wherein the alkyl group of poly-3-hydroxy-3-alkylpropionic acid is a methyl group or an ethyl group. 8. The oxidative decomposition type coated granular fertilizer according to claim 6, wherein the alkyl group of poly-2-hydroxy-2-alkylacetic acid is hydrogen, a methyl group or an ethyl group. 9. The oxidative decomposition type coated granular fertilizer according to claim 6, wherein R ^{1 of the} aliphatic polyester represented by the general formula (1) is an alkylene group having 2 or / and 4 carbon atoms. Embedded image (R ¹ and R ² represent an alkylene group having 2 to 10 carbon atoms.) 10. The oxidative decomposition type coated granular fertilizer according to claim 6, wherein R ^{2 of the} aliphatic polyester represented by the general formula (1) is an alkylene group having 2 or / and 4 carbon atoms. Embedded image (R ¹ and R ² represent an alkylene group having 2 to 10 carbon atoms.) 11. The oxidative decomposition type coated granular fertilizer according to claim 1, wherein the particle size of the biodegradable polyester fine particles is in the range of 0.5 to 100 μm.