Method of using coated fertilizer, and method of producing fragments of shells

Abstract

To provide a method of using a coated fertilizer containing a coating film strong enough to withstand mechanical fertilization, with its shells subsequent to elution of fertilizer components easily collapsible by a low load, and the shells subsequent to collapse being easily precipitated in paddy field water or the like, and to provide a method of producing fragments of the shell.SOLUTION: There is provided a method of using a coated fertilizer including a water-soluble granular fertilizer and a coating film covering the water-soluble granular fertilizer, comprising a fertilizing step of mechanically fertilizing the coated fertilizer, an elution step of eluting the water-soluble fertilizer component from the coated fertilizer subsequent to the fertilizing step, and a disintegration step of applying a load to the shell derived from the coating obtained subsequent to the elution step to generate fragments of the shell, in which the content of a substance present in the coating, with a weight average molecular weight of 10000 or more is 0 to 10%, the content of sulfur atoms present in the coating is 0 to 11 mass% relative to the total amount of atoms of an atomic number of 9 (fluorine) to 92 (uranium) in the periodic table of elements. A method of producing fragments of the shell is also provided.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to methods of using coated fertilizers and methods of producing shell fragments. [Background technology]

[0002] Coated fertilizers are fertilizers in which the surface of a water-soluble fertilizer is covered with a film (coating) made of a laminate of organic or inorganic coating materials, thereby adjusting the time at which the fertilizer components inside are released. When coated fertilizers are used, particles (shells) made of the coating remain after the water-soluble fertilizer in the coated fertilizer has dissolved, and there is a possibility that these particles may be released into the environment. Therefore, the use of coatings that are more easily disintegrated is being considered. Patent Document 1 describes a coated fertilizer in which modified sulfur is used as a coating material, the modified sulfur being formed by melt-reacting sulfur and a sulfur modifier consisting of an alicyclic unsaturated hydrocarbon compound in a ratio of 100 parts by weight of sulfur to 1 to 35 parts by weight of sulfur modifier. Patent Document 2 describes a coated fertilizer that contains an α-olefin (co)polymer having a crystallization temperature within a specific range, a wax, and a filler, and uses a coating that has a structure in which the α-olefin (co)polymer and the wax are phase-separated and the wax is finely dispersed. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2007-84414 [Patent Document 2] International Publication No. 2012 / 147668 Summary of the Invention [Problem to be solved by the invention]

[0004] However, the coated fertilizer used in Patent Document 1, which contains a large amount of sulfur in the coating material, has a problem in that the coating strength is too low to withstand mechanical fertilization. Also, the coating (shell) of Patent Document 2 has a problem in that it is difficult to disintegrate after the fertilizing component has been eluted because the compressive strength is too high. The present disclosure aims to provide a method for using a coated fertilizer containing a coating that exhibits a good balance of the following characteristics: strength sufficient to withstand mechanical fertilization; the shells easily disintegrating under low load after the fertilizing components have been eluted; and the shells easily settling in water such as in a paddy field after disintegration; and a method for producing shell fragments. [Means for solving the problem]

[0005] The above problem can be solved by the following configuration.

[0006] <1> A method for using a coated fertilizer comprising a water-soluble granular fertilizer and a coating covering the water-soluble granular fertilizer, a fertilization step of mechanically applying the coated fertilizer; a dissolution step in which water-soluble fertilizer components are dissolved from the coated fertilizer after the fertilization step; a disintegration step of applying a load to the shell derived from the coating obtained after the elution step to generate fragments of the shell; and The coated fertilizer has a content of a substance having a weight average molecular weight of 10,000 or more in the coating of 0 to 10%, and A method for using a coated fertilizer, wherein the content of sulfur atoms in the coating is 0 to 11 mass % relative to the total content of atoms with atomic numbers 9 (fluorine) to 92 (uranium) in the periodic table of the elements. <2> The coated fertilizer has an average crushing load of 0.5 N or less for particles obtained by replacing the water-soluble granular fertilizer contained in the coated fertilizer with water. <1> A method for using the coated fertilizer described in claim 1. <3> For 100 of the coated fertilizers, after mechanical fertilization under the following conditions, 15 or fewer of the coated fertilizers have cracks on the surface of the coated fertilizer. <1> or <2> A method for using the coated fertilizer described in claim 1. (Conditions for mechanical fertilization) Using a side row fertilizer rice transplanter adjusted to apply a fertilizer rate of 5 kg / 10 a, 100 g of coated fertilizer is poured into the hopper and collected from the drop outlet. <4> In the disintegration step, a load of 0.5 N or more is applied to the shell derived from the coating. <1> ~ <3> 10. A method for using the coated fertilizer according to claim 9. <5> the content of the substance having a weight average molecular weight of 10,000 or more in the coating is 0 to 7%; <1> ~ <4> 10. A method for using the coated fertilizer according to claim 9. <6> the content of the substance having a weight average molecular weight of 10,000 or more in the coating is 0 to 3%; <1> ~ <5> 10. A method for using the coated fertilizer according to claim 9. <7> the content of the substance having a weight average molecular weight of 10,000 or more in the coating is 0 to 1%; <1> ~ <6> 10. A method for using the coated fertilizer according to claim 9. <8> the coating is substantially free of substances having a weight average molecular weight of 10,000 or more; <1> ~ <7> 10. A method for using the coated fertilizer according to claim 9. <9> the content of sulfur atoms in the coating is 0 to 9 mass% relative to the total content of atoms with atomic numbers 9 (fluorine) to 92 (uranium) in the periodic table of the elements; <1> ~ <8> 10. A method for using the coated fertilizer according to claim 9. <10> the content of sulfur atoms in the coating is 0 to 5 mass% relative to the total content of atoms with atomic numbers 9 (fluorine) to 92 (uranium) in the periodic table of the elements; <1> ~ <9> 10. A method for using the coated fertilizer according to claim 9. <11> the content of sulfur atoms in the coating is 0 to 2 mass% relative to the total content of atoms with atomic numbers 9 (fluorine) to 92 (uranium) in the periodic table of the elements; <1> ~ <10> 10. A method for using the coated fertilizer according to claim 9. <12> The coating is substantially free of sulfur atoms. <1> ~ <11> 10. A method for using the coated fertilizer according to claim 9. <13> a step of preparing a coated fertilizer comprising a water-soluble granular fertilizer and a coating covering the water-soluble granular fertilizer, wherein the content of a substance having a weight-average molecular weight of 10,000 or more in the coating is 0 to 10% and the content of sulfur atoms in the coating relative to the total content of atoms with atomic numbers 9 (fluorine) to 92 (uranium) in the periodic table of the elements is 0 to 11% by mass; A step in which the water-soluble granular fertilizer is dissolved from the coated fertilizer to form a shell derived from the coating; disintegrating the shells to form shell fragments; A method for producing shell fragments derived from the coated fertilizer, comprising: <14> forming the shell fragments occurs by at least one of soil compaction, soil repression, and soil tillage; <13> A method for producing shell fragments according to claim 1. <15> The mass of the largest fragment among the fragments generated in the disintegration step is 50% or less of the mass of the shell before the load is applied. <1> ~ <12> 10. A method for using the coated fertilizer according to claim 9. <16> The mass of the largest fragment formed in the step of forming the shell fragments is 50% or less of the mass of the shell before being disintegrated. <13> or <14> A method for producing shell fragments according to claim 1. <17> The shell fragments have sedimentation properties in water. <13> , <14> or <16> A method for producing shell fragments according to claim 1. [Effects of the Invention]

[0007] According to the present disclosure, it is possible to provide a method for using a coated fertilizer containing a coating that exhibits a good balance of the following characteristics: strength sufficient to withstand mechanical fertilization; the shells easily disintegrating under low load after the fertilizing components have been eluted; and the shells easily settling in water such as in a paddy field after disintegration; and a method for producing shell fragments. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a schematic diagram showing a cross section of an example of a coated fertilizer. DETAILED DESCRIPTION OF THE INVENTION

[0009] The present disclosure will be described in detail below, but the following description of the constituent elements is an example of an embodiment of the present disclosure, and the present disclosure is not limited to these specific details. Various modifications can be made within the scope of the gist of the present disclosure. In this specification, the symbol "to" is used to mean that the numerical values ​​before and after it are included as the lower limit and upper limit.

[0010] (layer) In this specification, the term "layer" refers to a state in which raw materials supplied for coating have hardened or solidified to cover the coated particles (water-soluble granular fertilizer or coated water-soluble granular fertilizer). A state in which further raw materials are supplied on top of the layer and hardened or solidified may also be referred to as a "layer." Furthermore, a layer may or may not have boundaries between layers. When the terms "first layer," "second layer," etc. are used in this specification, for example, the first layer refers to a layer obtained by hardening or solidifying the coating material derived from the raw materials supplied the first time, and may or may not have boundaries within the layer, and the ratio and distribution of the components constituting the layer may be uniform or non-uniform.

[0011] [1. Coated fertilizer] The coated fertilizer of the present disclosure is a coated fertilizer including a water-soluble granular fertilizer and a coating covering the water-soluble granular fertilizer, in which the content of substances having a weight-average molecular weight of 10,000 or more in the coating is 0 to 10%, and the content of sulfur atoms in the coating relative to the total content of atoms with atomic numbers 9 (fluorine) to 92 (uranium) in the periodic table of the elements is 0 to 11 mass%.

[0012] The content of substances having a weight-average molecular weight of 10,000 or more in the coating is defined as the ratio of peak areas determined by the following high-temperature GPC measurement. (High temperature GPC measurement) The coated fertilizer is crushed, and then the water-soluble components are removed by washing with water, followed by filtration to obtain the water-insoluble portion. The water-insoluble portion obtained is dried in a dryer at 80°C for 24 hours to obtain a measurement sample. The sample is weighed so that the estimated organic content is 1 mg / mL (solvent: 1,2,4-trichlorobenzene), and is dissolved by shaking at 140°C for 1 hour. If there is any insoluble matter in the solution after the above shaking dissolution, it is removed by hot filtration using a 0.5 μm sintered filter, and only the soluble matter is used as the test sample. Measurements were performed using an HLC-8321GPC / HT (detector: RI) and a TSKgel guard column H. HR (30) HT x 1, TSKgel GMH HR The column was run using three -H(20)HT columns (manufactured by Tosoh) and 1,2,4-trichlorobenzene as the eluent at a flow rate of 1.0 ml / min, an injection volume of 0.3 mL, and a column temperature of 140°C. Molecular weight analysis is performed by measuring polystyrene with known molecular weights (15 points in the molecular weight range of 20,000,000 to 941) in advance, obtaining a calibration curve of molecular weight versus retention time, measuring the above test sample, and determining the relative molecular weight (polystyrene equivalent value) from the peak position and retention time of the obtained chromatogram. In the present disclosure, the content of substances having a weight average molecular weight of 10,000 or more is calculated using the following formula. (area of ​​the region in the chromatograph where the molecular weight is 10,000 or more) × 100 / (total peak area in the chromatograph)

[0013] The content of sulfur atoms relative to the total content of atoms with atomic numbers from 9 (fluorine) to 92 (uranium) in the periodic table of the elements in the coating is determined by the following X-ray fluorescence measurement. (X-ray fluorescence measurement) The coated fertilizer is crushed, and then the water-soluble components are removed by washing with water, followed by filtration to obtain the water-insoluble portion. The water-insoluble portion obtained is dried in a dryer at 80°C for 24 hours to obtain a measurement sample. The measurement sample is measured using an X-ray fluorescence analyzer (Rigaku "Supermini200"), which scans all elements from atomic number 9 (fluorine) to 92 (uranium) on the periodic table to determine the component content of the sample. The excitation X-ray tube conditions are 50 kV and 4.0 mA. In the present disclosure, the content of sulfur atoms relative to the total content of atoms with atomic numbers 9 (fluorine) to 92 (uranium) in the periodic table of the elements in the coating is calculated using the following formula. (Sulfur atom content in the coating) x 100 / (total content of atoms in the coating with atomic numbers 9 (fluorine) to 92 (uranium) in the periodic table of the elements)

[0014] The content of substances having a weight-average molecular weight of 10,000 or more in the coating is preferably 0 to 7%, more preferably 0 to 3%, and even more preferably 0 to 1%. It is particularly preferable that the coating is substantially free of substances having a weight-average molecular weight of 10,000 or more. "Substantially free of substances having a weight-average molecular weight of 10,000 or more" means that the content of substances having a weight-average molecular weight of 10,000 or more in the coating is below the lower detection limit, for example, 0.1% or less.

[0015] The content of sulfur atoms in the coating relative to the total content of atoms with atomic numbers 9 (fluorine) to 92 (uranium) in the periodic table of the elements is preferably 0 to 9 mass%, more preferably 0 to 5 mass%, and even more preferably 0 to 2 mass%. It is particularly preferable that the coating is substantially free of sulfur atoms. "Substantially free of sulfur atoms" means that the content of sulfur atoms in the coating relative to the total content of atoms with atomic numbers 9 (fluorine) to 92 (uranium) in the periodic table of the elements is below the lower detection limit, for example, less than 1% by mass. Although the details are unclear, sulfur exists in a crystalline state rather than a polymer, and therefore if the content in the coating is too high, the strength of the coating tends to decrease and it tends to be difficult to withstand mechanical fertilization. Therefore, the lower the content of sulfur atoms in the coating, the better.

[0016] Furthermore, one preferred embodiment of the present disclosure also relates to a method for using a coated fertilizer that includes a water-soluble granular fertilizer and a coating that covers the water-soluble granular fertilizer, wherein the average crushing load of particles obtained by replacing the water-soluble granular fertilizer contained in the coated fertilizer with water is, for example, 0.5 N or less. The lower limit of the average crushing load is not particularly limited, but may be, for example, 0.01 N or more.

[0017] For every 100 coated fertilizers of the present disclosure, it is preferable that, after mechanical fertilization under the conditions described below, 15 or fewer coated fertilizers have cracks on the surface when observed under an optical microscope. (Conditions for mechanical fertilization) Using a side-strip fertilizer rice transplanter adjusted to a fertilizer rate of 5 kg / 10 a, 100 g of coated fertilizer is poured into the hopper and collected from the drop port. For example, an EP6D (manufactured by Kubota Corporation) can be used as the side-strip fertilizer rice transplanter.

[0018] <Water-soluble granular fertilizer> The coated fertilizer of the present disclosure includes a water-soluble granular fertilizer. The water-soluble granular fertilizer is used as a fertilizer component. The water-soluble granular fertilizer preferably includes a water-soluble fertilizer component. The water-soluble granular fertilizer is not particularly limited as long as it is water-soluble. Examples of water-soluble granular fertilizers include urea, ammonium chloride, ammonium sulfate, ammonium nitrate, potassium chloride, potassium nitrate, sodium nitrate, potassium ammonium phosphate, ammonium phosphate, and calcium ammonium phosphate, with urea being preferred. The water-soluble granular fertilizer may be a fertilizer using one type selected from the above, or a compound fertilizer using two or more types. Furthermore, the water-soluble granular fertilizer may contain water-soluble or insoluble impurities, etc., as long as the properties of the fertilizer are not significantly affected.

[0019] The size and shape of the water-soluble granular fertilizer are not particularly limited, and those of commonly used sizes can be used. For example, for convenience in spreading it on farms using existing machinery, the fertilizer is preferably solid particles (e.g., spherical, approximately spherical, rod-like, needle-like, rectangular, flat, irregular, etc.), and the particle size determined by sieving is preferably 1.0 mm to 5.0 mm, more preferably 2.0 mm to 4.0 mm.

[0020] The water-soluble granular fertilizer may be commercially available or may be produced by a known method such as extrusion granulation or compression granulation.

[0021] <Coating> The coating in the coated fertilizer of the present disclosure refers to the entire film covering the water-soluble granular fertilizer. The film on the water-soluble granular fertilizer may be in contact with the surface of the water-soluble granular fertilizer, or any film or layer may be interposed between the water-soluble granular fertilizer and the film. Also, any particles may be present on the surface of the coating. Note that in this specification, particles attached to the surface of the coating after the coating is formed are not included in the coating. In the coated fertilizer of the present disclosure, the coating is composed of at least one layer, preferably at least two layers, and more preferably at least four layers. The upper limit of the number of layers constituting the coating is not particularly limited, but may be, for example, 100 or less, or 50 or less. In the present disclosure, when there are two or more layers covering the water-soluble granular fertilizer, the entire film consisting of two or more laminated layers will be referred to as the "coating". When the coating has two or more layers, the layers may have different compositions, or they may all have the same composition. Note that "composition" refers to the components contained in the layer and their content.

[0022] The coating preferably contains a salt of a fatty acid having 20 or more carbon atoms, and more preferably contains a salt of a fatty acid having 20 or more carbon atoms and a wax. Fatty acids having 20 or more carbon atoms are also called "specific fatty acids," and salts of fatty acids having 20 or more carbon atoms are also called "salts of specific fatty acids." Furthermore, among all the fatty acid salts contained in the coating, salts of fatty acids other than the salt of the specific fatty acid may be contained to the extent that the various performance properties of the coating are not significantly impaired. However, it is desirable that the main component of the fatty acid salt contained in the coating is the salt of the specific fatty acid. The "main component" refers to the component that is contained most abundantly among the fatty acid salts. For example, if the total mass of the fatty acid salts contained in the coating is taken as 100 mass%, it may be a component with a content of 60 mass% or more. Furthermore, it may be a component with a content of 75 mass% or more, more preferably a component with a content of 80 mass% or more, even more preferably a component with a content of 85 mass% or more, and particularly preferably a component with a content of 90 mass% or more. There is no particular upper limit to the content of the main component, but it may be, for example, 100 mass% or less, preferably 98 mass% or less. Furthermore, when there are two or more types of specific fatty acid salts, the total value thereof may be used as the "content of the specific fatty acid salt."

[0023] When the coating has two or more layers, the salt of the specific fatty acid and the wax may be contained in the same layer or in separate layers (i.e., one layer may contain the salt of the specific fatty acid but not the wax, and another layer may contain the wax but not the salt of the specific fatty acid). The coating is composed of at least one layer, and preferably has at least one layer containing a salt of a specific fatty acid and a wax. It is more preferable that the coating is composed of at least four layers, and that at least four layers contain a salt of a specific fatty acid and a wax. It is preferable that the coating is composed of at least one layer, and that the layer closest to the water-soluble granular fertilizer (the layer in contact with the surface of the water-soluble granular fertilizer) contains a salt of a specific fatty acid and a wax.

[0024] FIG. 1 is a schematic diagram showing a cross section of an example of a coated fertilizer according to the present disclosure. The coated fertilizer 1 in FIG. 1 includes a water-soluble granular fertilizer F and a coating L that covers the water-soluble granular fertilizer F. The coating L is composed of four layers, namely, a first layer L1, a second layer L2, a third layer L3, and a fourth layer L4, in order from the side closest to the water-soluble granular fertilizer F. It is preferable that at least one of the first layer L1, the second layer L2, the third layer L3, and the fourth layer L4 contains a salt of a specific fatty acid, and that at least one of the layers contains a wax. It is preferable that at least one of the first layer L1, the second layer L2, the third layer L3, and the fourth layer L4 contains a salt of a specific fatty acid and a wax. It is more preferable that the first layer L1 contains a salt of a specific fatty acid and a wax. It is particularly preferred that the first layer L1, the second layer L2, the third layer L3 and the fourth layer L4 contain a salt of a specific fatty acid and a wax. 1, the boundaries between the layers L1 to L4 are clearly shown, but the boundaries may be unclear. Furthermore, the thicknesses of the layers may be the same or different.

[0025] The thickness of the coating can be changed appropriately according to the desired elution pattern, and may be, for example, 10 μm to 250 μm, 30 μm to 200 μm, or 50 μm to 150 μm. The total thickness of the coating is the sum of the thicknesses of the individual layers. The thickness of each layer constituting the coating is not particularly limited and can be changed as appropriate depending on the thickness of the coating, but a thickness of 5 μm to 30 μm is preferred from the standpoint of ease of coating.

[0026] The total mass of the coating is preferably 1.0 to 30 mass %, more preferably 2.0 to 25 mass %, and even more preferably 3.0 to 20 mass %, based on the total mass of the coated fertilizer. The ratio of the total mass of the coating to the total mass of the coated fertilizer is also called the coverage rate. Coverage rate (%) = (total mass of coating / total mass of coated fertilizer) x 100

[0027] The moisture permeability of the coating to fertilizer at 40°C is 52g / (m 2 24 hours or less is preferable. The moisture permeability of fertilizer indicates the sum of the ease of permeation of water through the coating film and the ease of permeation of urea dissolved in water (urea water) through the coating film. 2 ·24h) or less, and more preferably 20g / (m 2 ·24h) or less, 10g / (m 2 24 hours or less may be used.

[0028] <Other optional ingredients> The coated fertilizer of the present disclosure may have an optional material on the surface of the coating to prevent scratches, prevent floating of the coated fertilizer in water or the shell after disintegration, prevent caking, etc. Examples include talc, silica, diatomaceous earth, etc. These optional materials adhere to the coating by being applied to the surface of the coated fertilizer. Furthermore, as described below, they may be mixed into the coating as one component of the coating material. Furthermore, the coated fertilizer of the present disclosure may contain unreacted raw materials (for example, fatty acids such as specific fatty acids, metal hydroxides, etc.) and reaction by-products during coating formation, which will be described later.

[0029] The components that may be contained in the coating are described below.

[0030] (salts of specific fatty acids) The salt of the specific fatty acid is preferably a salt of a fatty acid having 20 or more carbon atoms. From the viewpoint of the strength of the coating, it is more preferable to contain a salt of a fatty acid having 21 or more carbon atoms, and it is particularly preferable to contain a salt of a fatty acid having 31 or more carbon atoms. Furthermore, from the viewpoint of the strength of the coating, it is even more preferable that the main component of the salt of the fatty acid contained in the coating is a salt of a fatty acid having 31 or more carbon atoms. There is no particular upper limit on the number of carbon atoms in the salt of the specific fatty acid, but it may be, for example, 100 or less.

[0031] The salt of the specific fatty acid may be a salt of a monobasic acid, a salt of a dibasic acid, or a salt of a tribasic acid, but preferably contains at least one of a salt of a dibasic acid and a salt of a tribasic acid. The salt of the specific fatty acid contained in the coating may be one type or two or more types. The salt of the specific fatty acid preferably includes at least one of a salt of a dimer acid and a salt of a trimer acid. More preferably, at least one of the dimer acid salt and the trimer acid salt may account for a total of 60% by mass or more of the total amount of the specific fatty acid salt contained in the coating. Even more preferably, the coating may contain at least 60% by mass or more of the dimer acid salt, and even more preferably, the coating may contain at least 70% by mass or more of the dimer acid salt. The upper limit of the content of the dimer acid salt is not particularly limited, but may be, for example, 100% by mass or less, 90% by mass or less, or 85% by mass or less.

[0032] The salt of the specific fatty acid preferably includes a salt of a fatty acid having at least one of a branched structure and a cyclic structure. The specific fatty acid having the above structure is suitable because it tends to be compatible with the wax and to easily retain the wax inside the fatty acid salt of the coating. Furthermore, it is more preferable that the main component of the fatty acid salt contained in the coating is a salt of a fatty acid having at least one of a branched structure and a cyclic structure. The branched structure refers to a structure in which at least one hydrogen atom in the hydrocarbon chain of a fatty acid is replaced with a carbon atom, and the ring structure refers to a ring-shaped hydrocarbon.

[0033] The salt of the specific fatty acid may be a salt of a saturated fatty acid or a salt of an unsaturated fatty acid. The salt of the specific fatty acid is preferably a salt of an aliphatic carboxylic acid having 20 or more carbon atoms. The salt of the specific fatty acid is preferably a salt of a vegetable fatty acid having 20 or more carbon atoms. Specific examples of the specific fatty acid in the salt of the specific fatty acid will be described later.

[0034] The salt of the specific fatty acid is preferably a metal salt of the specific fatty acid, and more preferably at least one of an alkali metal salt of the specific fatty acid and an alkaline earth metal salt of the specific fatty acid. For example, it is more preferable that the fatty acid be at least one selected from the group consisting of sodium salts of specific fatty acids, potassium salts of specific fatty acids, lithium salts of specific fatty acids, calcium salts of specific fatty acids, and magnesium salts of specific fatty acids. Since the salt of a specific fatty acid tends to be difficult to coat even when the salt itself is supplied onto a water-soluble granular fertilizer, it is preferable to use one obtained by the production method described below. Specifically, a coating of the salt of a specific fatty acid can be obtained by reacting the specific fatty acid with a metal hydroxide on the water-soluble granular fertilizer. From the viewpoint of ease of reaction with the specific fatty acid to form a salt of the specific fatty acid, it is preferable to use calcium hydroxide as the metal hydroxide. In other words, it is particularly preferable that the salt of the specific fatty acid is a calcium salt of the specific fatty acid.

[0035] The content of the salt of the specific fatty acid is not particularly limited as long as the desired coating film is obtained, and is, for example, preferably 1 to 99% by mass, more preferably 5 to 95% by mass, and even more preferably 10 to 90% by mass, relative to the total mass of the coating film.

[0036] (wax) The wax is not particularly limited. The wax is preferably one that becomes liquid at the coating temperature, and more preferably one having a melting point of 45 to 100° C. Examples include petroleum waxes such as paraffin wax, vegetable waxes such as carnauba wax, polymer waxes such as polyethylene wax, hydrogenated oils such as palm hydrogenated oil and beef tallow hydrogenated oil, and synthetic ester waxes.

[0037] The wax preferably contains at least one of a petroleum wax and a vegetable wax. Furthermore, when the mass of all waxes contained in the coating is taken as 100, the total content of petroleum wax and vegetable wax is more preferably 80 mass% or more, and it is even more preferable that all waxes contained in the coating are at least one of a petroleum wax and a vegetable wax.

[0038] The wax content is not particularly limited, but is preferably 1 to 40 mass %, more preferably 2.5 to 30 mass %, and even more preferably 5 to 20 mass %, relative to the total mass of the coating.

[0039] (Other ingredients) The coating preferably contains a salt of a specific fatty acid and a wax, and may further contain other components. Examples of other components include resins, surfactants, talc, diatomaceous earth, silica, sulfur powder, etc. When these are used as optional components in the coating, by supplying the above components before the coating material supplied to the coating device hardens or solidifies, the components can be incorporated into the coating as the coating material hardens or solidifies. The content of other components may be 0 to 20% by mass or 0 to 10% by mass relative to the total mass of the coating, provided that the content of substances having a weight-average molecular weight of 10,000 or more in the coating is 0 to 10% and the content of sulfur atoms in the coating relative to the total content of atoms with atomic numbers 9 (fluorine) to 92 (uranium) in the periodic table of the elements is 0 to 11% by mass.

[0040] The coating may or may not contain a resin (e.g., polyethylene, polyester, acrylic resin, polyurethane, etc.) as long as the content of substances having a weight-average molecular weight of 10,000 or more in the coating is 0 to 10%, but from the perspective of reducing the burden on the environment, it is preferable that the coating does not contain a resin.

[0041] [2. Manufacturing method of coated fertilizer] Hereinafter, the method for producing the coated fertilizer of the present disclosure will be described. The method for producing a coated fertilizer according to the present disclosure is preferably a method for producing a coated fertilizer comprising a water-soluble granular fertilizer and a coating covering the water-soluble granular fertilizer, and is a method for producing a coated fertilizer in which a coating containing a salt of a fatty acid having 20 or more carbon atoms and a wax is formed on the water-soluble granular fertilizer. The water-soluble granular fertilizer, the salt of a fatty acid having 20 or more carbon atoms (salt of a specific fatty acid), and the wax are as described above.

[0042] Examples of methods for producing a coated fertilizer include the following methods 1 and 2, and from the viewpoint of the strength of the coating, it is preferable to include the following method 1. Furthermore, from the viewpoint of easily preventing peeling between layers, it may be preferable to include the following method 1.

[0043] <Method 1> A method for producing a coated fertilizer, wherein the coating has at least one layer containing a salt of a specific fatty acid and a wax, and the method comprises carrying out the following steps 1 to 3 in this order: Step 1: A step of fluidizing or rolling the water-soluble granular fertilizer in the coating device. Step 2: Feeding the specific fatty acid and wax into the coating device Step 3: Supplying a metal hydroxide into a coating device, reacting the specific fatty acid with the metal hydroxide to generate a salt of the specific fatty acid, and forming a layer containing the salt of the specific fatty acid and wax.

[0044] <Method 2> A method for producing a coated fertilizer, wherein the coating has at least one layer A containing a salt of a specific fatty acid and at least one layer B containing a wax, and the method comprises carrying out the following steps 1, a, and b in this order: Step 1: A step of fluidizing or rolling the water-soluble granular fertilizer in the coating device. Step a: A step of supplying a specific fatty acid and a metal hydroxide into a coating device, reacting the specific fatty acid with the metal hydroxide to generate a salt of the specific fatty acid, and forming layer A. Step b: A step of supplying wax and a metal hydroxide into a coating device, solidifying the wax, and forming layer B on the surface of layer A.

[0045] First, method 1 will be described.

[0046] (Process 1) The above step 1 will now be described. In step 1, the water-soluble granular fertilizer is brought into a fluidized or tumbling state in the coating device. By bringing the water-soluble granular fertilizer into a fluidized or tumbling state, the uniformity of the coating film thickness is improved. The coating device is not particularly limited, but a device such as a rotary drum can be suitably used. In step 1, the temperature inside the device may be maintained at approximately the coating temperature in advance, and the water-soluble granular fertilizer may be heated before step 2. The coating temperature may be determined depending on the melting points of the specific fatty acid, wax, and water-soluble granular fertilizer used, and is not particularly limited, but is, for example, 20 to 150°C, and preferably 40 to 100°C. The coating temperature is the temperature at which steps 2 and 3 are performed. In addition, the humidity inside the device may be adjusted so as not to interfere with steps 2 and 3 described below.

[0047] (Process 2) The above step 2 will now be described. In step 2, the specific fatty acid and the wax are supplied into a coating device. In step 2, the specific fatty acid and the wax are supplied onto the water-soluble granular fertilizer in a fluidized or tumbling state. When fed into the coating device in step 2, the specific fatty acid and wax are preferably in a liquid state. It is preferable that the water-soluble granular fertilizer be maintained in a rolling or fluidized state when performing step 2. Furthermore, it is preferable that the water-soluble granular fertilizer be heated when performing step 2, in the same manner as in step 1, in order to maintain the temperature inside the apparatus at the coating temperature. The method for supplying the specific fatty acid and the wax is not particularly limited, and examples thereof include, but are not limited to, a spraying method and a dripping method. In addition, the water-soluble granular fertilizer may contain any component (e.g., water, a solvent, various additives, etc.) as long as the water-soluble granular fertilizer can maintain a solid state and does not impair the compatibility between the specific fatty acid and the wax or the reactivity between the specific fatty acid and the metal hydroxide, which will be described later.

[0048] The specific fatty acid and the wax may be supplied independently, or may be supplied after some or all of the components have been mixed together in advance. When supplied independently, they may be supplied simultaneously, sequentially, or at different timings, with some of them being supplied simultaneously.

[0049] Step 2 preferably includes step 2a of supplying the specific fatty acid and wax to the surface of the water-soluble granular fertilizer. Step 2a and step 3, which will be described later, form a layer that is closest to the water-soluble granular fertilizer and contains the salt of the specific fatty acid and the wax. For example, when the coated fertilizer 1 in FIG. 1 is produced by method 1 including step 2a, the first layer L1 becomes a layer that contains the salt of the specific fatty acid and the wax.

[0050] (Specific fatty acids) The specific fatty acid may be a fatty acid having 20 or more carbon atoms that can form the salt of the specific fatty acid and is liquid at the coating temperature. It is preferable to include a fatty acid having 21 or more carbon atoms, and more preferably a fatty acid having 31 or more carbon atoms. There is no particular upper limit on the number of carbon atoms in the specific fatty acid, but it may be, for example, 100 or less. The specific fatty acid may be a monobasic acid, a dibasic acid, or a tribasic acid, but preferably contains at least one of a dibasic acid and a tribasic acid. The specific fatty acid preferably includes at least one of a dimer acid and a trimer acid. The specific fatty acid preferably includes a fatty acid having at least one of a branched structure and a cyclic structure. The specific fatty acid may be a saturated fatty acid or an unsaturated fatty acid. The specific fatty acid is preferably an aliphatic carboxylic acid having 20 or more carbon atoms. The specific fatty acid is preferably a vegetable fatty acid having 20 or more carbon atoms.

[0051] Suitable examples of the specific fatty acids include known saturated fatty acids and conjugated fatty acids having 20 or more carbon atoms. Commercially available products may be used, or the specific fatty acids may be synthesized by known methods. Specific examples of commercially available specific fatty acids include SB-20, IPU-22, and IPS-22 (all manufactured by Okamura Oil Mills), Cyclocarboxypropyloleic acid (manufactured by ALFA Chemistry), Tsunodym 205, and Tsunodym 346 (manufactured by Tsuno Oleochemicals). Examples of vegetable fatty acids include those obtained by modifying oleic acid, linoleic acid, linolenic acid, erucic acid, and dehydrated condensed castor oil fatty acid to have 20 or more carbon atoms, or by dimerizing or trimerizing the modified fatty acids.

[0052] (Step 3) The above step 3 will now be described. In step 3, a metal hydroxide is supplied into the coating device, and the specific fatty acid and the metal hydroxide are reacted to produce a salt of the specific fatty acid, thereby forming a layer containing the salt of the specific fatty acid and wax. The metal hydroxide is preferably in the form of a powder when supplied into the coating apparatus in step 3. When the metal hydroxide is in the form of a powder, the water content and particle shape are preferably adjusted to such an extent that the reactivity between the specific fatty acid and the metal hydroxide is not impaired. For example, in the coating apparatus prior to the reaction between the specific fatty acid and the metal hydroxide, the water may contain 50% by mass or less, more preferably 0.1 to 30% by mass, of water when the total mass of the specific fatty acid used in step 2, the wax, and the metal hydroxide used in step 3 is taken as 100. It is desirable that the water-soluble granular fertilizer be maintained in a rolling or fluidized state when performing step 3. Furthermore, when performing step 3, it is desirable that heating be performed in order to maintain the temperature inside the apparatus at the coating temperature, as in step 1. The method for supplying the metal hydroxide is not particularly limited. For example, when the metal hydroxide is a liquid, the spraying method or the dropping method can be used, as in step 2. When the metal hydroxide is a solid, the method can be, but is not limited to, a method of mechanically supplying the metal hydroxide while dispersing it (mechanical method) or a method of supplying the metal hydroxide together with a gas (airflow method). The supply may be made in its entirety at once, or may be made gradually over a predetermined time period, or may be made in portions at predetermined time intervals.

[0053] (metal hydroxide) The metal hydroxide preferably contains at least one of an alkali metal hydroxide and an alkaline earth metal hydroxide, and more preferably contains at least one selected from the group consisting of sodium hydroxide, potassium hydroxide, lithium hydroxide, calcium hydroxide, and magnesium hydroxide. Furthermore, as mentioned above, calcium hydroxide is more preferably used because it reacts well with the specific fatty acid. The mass ratio of the metal hydroxide used in step 3 to the specific fatty acid used in step 2 (mass of metal hydroxide / mass of specific fatty acid) is preferably 10 / 1 to 0.5 / 1, and more preferably 5 / 1 to 1 / 1.

[0054] After step 3, it is preferable to further perform steps 2 and 3 one or more times each. It is preferable to perform four or more cycles, with one cycle being Step 2 and Step 3 performed in this order. For example, when the coated fertilizer 1 in Fig. 1 is produced by Method 1, which performs four cycles, with Step 2 and Step 3 performed in this order once each, the first layer L1, the second layer L2, the third layer L3, and the fourth layer L4 all contain the salt of the specific fatty acid and the wax. In addition, in Method 1, after Step 1, at least one of Step a and Step b of Method 2 may be carried out one or more times.

[0055] Next, method 2 will be explained. Step 1 is the same as step 1 of Method 1 described above.

[0056] (Step a) The above step a will now be described. In step a, the specific fatty acid and a metal hydroxide are supplied into a coating device, and the specific fatty acid and the metal hydroxide are reacted to generate a salt of the specific fatty acid, thereby forming layer A. Layer A is one of the layers that make up the coating. By step a, layer A containing the salt of the specific fatty acid is formed on the water-soluble granular fertilizer in a fluidized or tumbling state. The specific fatty acid is preferably in a liquid state when fed into the coating device in step a. When performing step a, it is preferable that the water-soluble granular fertilizer be maintained in a rolling or fluidized state. Furthermore, when performing step a, it is preferable that the inside of the apparatus be heated to maintain the coating temperature, as in step 1. The method for supplying the specific fatty acid and the method for supplying the metal hydroxide may be the same as those in the above-mentioned steps 2 and 3. When the metal hydroxide is in powder form, it is preferable to adjust the water content and particle shape to such an extent that the reactivity between the specific fatty acid and the metal hydroxide is not impaired. For example, in the coating device prior to the reaction of the specific fatty acid with the metal hydroxide, when the total mass of the specific fatty acid and the metal hydroxide used in step a is taken as 100, the water content may be 60 mass % or less, more preferably in the range of 0.2 to 40 mass %. The specific fatty acid and the metal hydroxide may be supplied independently. When supplied independently, they may be supplied simultaneously, sequentially, or at different timings, with some of them being supplied simultaneously. From the viewpoint of ease of coating, it is preferable to start supplying the metal hydroxide at least after the supply of the specific fatty acid has been started. The specific fatty acid and metal hydroxide are as described above.

[0057] (Step b) The above step b will now be described. In step b, wax and a metal hydroxide are fed into a coating device, and the wax is solidified to form layer B on the surface of layer A. The wax is preferably in a liquid state when fed into the coating device in step b. When performing step b, it is preferable that the water-soluble granular fertilizer be maintained in a rolling or fluidized state. Furthermore, when performing step b, it is preferable that the inside of the apparatus be heated to maintain the coating temperature, as in step 1. The wax may be supplied in the same manner as in step 3 described above. The method for supplying the metal hydroxide may be the same as in the above-described step a. The wax and the metal hydroxide may be supplied independently. When supplied independently, they may be supplied simultaneously, sequentially, or at different timings, with some of them being supplied simultaneously. From the viewpoint of ease of coating, it is preferable to start supplying the metal hydroxide at least after the wax has been supplied. The wax and metal hydroxide are as described above.

[0058] After step b, it is preferable to further carry out step a and step b at least once each. It is preferable to perform four or more cycles, each cycle being one in which step a and step b are performed in this order. For example, when the coated fertilizer 1 of Fig. 1 is produced by method 2, which involves two cycles, each cycle being one in which step a and step b are performed in this order, the first layer L1 and the third layer L3 become layers containing a salt of a specific fatty acid (layer A), and the second layer L2 and the fourth layer L4 become layers containing a wax (layer B). In Method 2, after Step 1, at least one of Step 2 and Step 3 of Method 1 may be carried out one or more times.

[0059] After the above-mentioned methods 1 and 2, the rolling or fluidizing state may be further maintained to dry the coating surface or promote the reaction of the unreacted specific fatty acid. At this time, the heating inside the coating apparatus may be stopped and the temperature may be lowered to the desired temperature.

[0060] [3. How to use coated fertilizer] A method for using a coated fertilizer according to the present disclosure is a method for using a coated fertilizer comprising a water-soluble granular fertilizer and a coating covering the water-soluble granular fertilizer, a fertilization step of mechanically applying the coated fertilizer; a dissolution step in which water-soluble fertilizer components are dissolved from the coated fertilizer after the fertilization step; a disintegration step of applying a load to the shell derived from the coating obtained after the elution step to generate fragments of the shell; and The coated fertilizer has a content of a substance having a weight average molecular weight of 10,000 or more in the coating of 0 to 10%, and The method for using the coated fertilizer is such that the content of sulfur atoms in the coating is 0 to 11 mass % relative to the total content of atoms with atomic numbers 9 (fluorine) to 92 (uranium) in the periodic table of the elements.

[0061] The coated fertilizer of the present disclosure is spread onto soil by mechanical fertilization, and water-soluble fertilizer components are gradually released through the coating during the plant cultivation period, supplying nutrients to the plant. In conventional coated fertilizers, the husks (particles made of the coating) tend to retain their shape and remain in the soil after the water-soluble fertilizer components are released. When flooded cultivation is carried out in subsequent years, the husks must be collected to prevent them from floating to the water surface and being washed away from the field. To avoid this collection process, it is desirable for the husks to easily disintegrate after the water-soluble fertilizer components have been released. The coated fertilizer of the present disclosure does not collapse or damage the coating surface when applied mechanically, and the shell formed after the water-soluble fertilizer components are released from the coated fertilizer collapses when an external force exceeding the average crushing load of the shell is applied, generating fragments derived from the collapsed shell. It has been found that the resulting shell fragments are unlikely to float in water.

[0062] (Fertilization process) The fertilizing step is not particularly limited as long as it involves spreading the fertilizer on the soil using a known device, such as a full layer fertilizer applicator or a side stripe fertilizer applicator. Furthermore, when applying fertilizer, only the coated fertilizer of the present disclosure may be spread, or a mixture of the coated fertilizer of the present disclosure and other granular materials may be spread.

[0063] (Elution process) In the dissolution process, the fertilizing components of the water-soluble granular fertilizer are dissolved from inside the applied coated fertilizer to the outside of the coating. Specifically, this occurs when moisture in the environment penetrates into the coating, causing the solid water-soluble granular fertilizer to dissolve in water. Examples of moisture in the environment include precipitation (rain, sprinkling, etc.), atmospheric humidity, and water used in irrigation cultivation in rice fields, etc.

[0064] After the above-mentioned leaching occurs, a shell derived from the coating, which is the shell after the water-soluble fertilizer components are released (hereinafter, sometimes referred to as "particles made of the coating"), is obtained. The shell does not disintegrate significantly during the leaching process, and tends to maintain its particle shape, or at least maintain its particle shape with some holes. Furthermore, if leaching occurs in water, for example, during irrigation cultivation, the shell contains at least water as an inclusion. Furthermore, if leaching occurs in the atmosphere, the inclusion may contain air or may be flattened and empty.

[0065] The average crushing load of the shell immediately after dissolution is preferably 0.7 N or less. If the average crushing load is within the above range, the shell will be easily broken into fragments in the disintegration step described below. The lower limit of the average crushing load is not particularly limited, but may be, for example, 0.01 N or more. Preferably, the particles obtained by replacing the water-soluble granular fertilizer contained in the coated fertilizer with water may have an average crushing load of 0.5 N or less. Preferably, the water-soluble granular fertilizer is eluted to the outside of the coating, and the average crushing load of the particles that are not replaced with water inside may be 0.6 N or less.

[0066] (Disintegration process) In the disintegration step, an external force is applied to the resulting coating-derived shell to disintegrate the shell and obtain fragments. The magnitude of this external force need only be equal to or greater than the strength of the shell, and can be, for example, a load of 0.5 N or more applied to the shell. The force may be preferably greater than 0.5 N, more preferably greater than 0.7 N.

[0067] Examples of the external force include soil compression due to soil drying, soil compaction by a harvester or the like, and soil tillage by a cultivator or the like.

[0068] When the disintegrated shells retain the shape of the coated fertilizer, whether the shells settle in water or float to the water surface depends on the amount of air contained in the shells. As the shells disintegrate into fragments, the air is released from the shells, and the fragmented shell fragments tend to settle in water. In this specification, the sedimentation property of the collapsed shells was evaluated by agitating the shells with a predetermined weight in water, leaving them to stand for 1 minute until the surface layer settled, and then visually observing the surface of the water. If no floating matter was observed, the shells were deemed to have "settling property."

[0069] To allow the shells that have been broken into fragments (hereinafter sometimes referred to as "shell fragments" or "fragments") to exhibit greater sedimentation properties in water, it is preferable that the mass of the largest fragment among all the broken shells is 50% or less, more preferably 48% or less, of the mass of the shell before the breakup. In this specification, "fragmented" refers to a shape having openings that are too small to contain air bubbles inside the shell, and "fragments" refers to the fragmented particles and particle groups. Furthermore, when simply describing "collapsed shells," it is acceptable for the shells to be broken into fragments and still retain the shape of the coated fertilizer, as long as at least a portion of the shell is broken.

[0070] Since the inside of the shell exists in various forms, from liquid to gas, it is preferable that it disintegrates under a smaller external force, not just the inclusions. Furthermore, it is desirable that the shell fragments derived from the coated fertilizer do not float on water. A configuration in which the shell fragments do not float on water is preferable because it can prevent the shell fragments from being washed away outside the field. When a coated fertilizer having the configuration specified in the present disclosure is used, the surface of the coated fertilizer is less likely to be damaged when it is spread on the soil by a machine such as a full-layer fertilizer applicator or a side-stripe fertilizer applicator, and the husks from which the water-soluble fertilizer components have been eluted are easily disintegrated by external forces such as soil compression due to soil drying, soil compaction by a harvester, or soil tillage by a cultivator, and the disintegrated husks are likely to settle in water in paddy fields, etc., thereby preventing the fertilizer from being washed away from the field. Furthermore, the coated fertilizer of the present disclosure is more preferably used in flooded cultivation. [Example]

[0071] Examples of the present disclosure will be described below, but the present disclosure is not limited to the following examples.

[0072] [Sample preparation] (Comparative Example 1) A commercially available granular coated fertilizer (manufactured by San Agro Co., Ltd., trade name: SCU(S)) was used as is.

[0073] (Comparative Example 2) A commercially available granular coated fertilizer (manufactured by San Agro Co., Ltd., trade name: SCU(LL)) was used as is.

[0074] (Comparative Example 3) Chemical fertilizers and coated fertilizers were visually distinguished from each other in a commercially available compound fertilizer (manufactured by JCAM AGRI Co., Ltd., product name: Harebare-kun), and the coated fertilizers were obtained by removing the chemical fertilizers.

[0075] [Materials used] The materials used in preparing the coated fertilizers of the following Examples and Comparative Examples will be described.

[0076] <Water-soluble granular fertilizer> Urea with particle diameters of 2.0 mm to 4.0 mm was used.

[0077] <Specific fatty acid 1> Tsunodim 205 (containing the most dimer acid (36 carbon atoms)) manufactured by Tsuno Oleochemicals was used.

[0078] <Specific fatty acid 2> Branched dibasic fatty acid SB-20 (containing the most dimer acid (20 carbon atoms)) manufactured by Okamura Essential Oils was used.

[0079] <Wax 1> Paraffin wax (melting point: 50°C) manufactured by Nippon Seiro was used.

[0080] <Wax 2> The hardened palm oil A (melting point: 58°C) manufactured by New Japan Chemical Co., Ltd. was used.

[0081] <Metal hydroxide> The fine particle slaked lime M-300 manufactured by Inoue Mitsuyoshi Shoten was used.

[0082] <Sulfur powder> Sulfur powder manufactured by Wako Pure Chemical Industries was used.

[0083] <Polyol> Plaxel 205 (polycaprolactone diol, weight average molecular weight 500) manufactured by Daicel was used.

[0084] <Polyisocyanate> 4,4-Diphenylmethane diisocyanate manufactured by Tokyo Chemical Industry Co., Ltd. was used.

[0085] [Sample preparation] Example 1 In Example 1, a coated fertilizer was produced by the above-mentioned Method 1, as detailed below. Water-soluble granular fertilizer (1000 g) was charged into a drum-type rolling coating device with a diameter of 300 mm, and while rolling at 25 rpm (rotations per minute), the temperature inside the coating device was maintained at 70°C using a hot air generator (Step 1). Next, while maintaining the rolling state, a liquid mixture of specific fatty acid 1 (2.68 g) and wax 1 (1.32 g) was prepared and added dropwise into the device through the supply port (step 2). Next, while maintaining the rolling state, after 3 minutes, metal hydroxide (9.60 g) was supplied into the device, and the rolling state was maintained for 3 minutes (step 3). In step 3, the metal hydroxide reacted with specific fatty acid 1, and a solidified layer was formed on the surface of the water-soluble granular fertilizer. Next, the following was counted as one cycle and 13 cycles were repeated. (1 cycle) While maintaining the rolling state, a mixture of specific fatty acid 1 (2.68 g) and wax 1 (1.32 g) was dripped into the device through the supply port (step 2), and after 3 minutes, metal hydroxide (9.60 g) was supplied into the device and the rolling state was maintained for 3 minutes (step 3). Next, after rolling for 6 minutes, the mixture was slowly cooled to room temperature (about 25°C) to obtain a coated fertilizer.

[0086] Example 2 A coated fertilizer was obtained in the same manner as in Example 1, except that the number of cycles was changed to 20.

[0087] Example 3 A coated fertilizer was obtained in the same manner as in Example 2, except that Wax 2 was used instead of Wax 1.

[0088] Example 4 A coated fertilizer was obtained in the same manner as in Example 1, except that a mixture of metal hydroxide (9.30 g) and sulfur powder (0.30 g) mixed in advance was used instead of the metal hydroxide.

[0089] Example 5 A coated fertilizer was obtained in the same manner as in Example 1, except that a mixture of metal hydroxide (8.60 g) and sulfur powder (1.00 g) mixed in advance was used instead of the metal hydroxide.

[0090] Comparative Example 4 A coated fertilizer was obtained in the same manner as in Example 1, except that a mixture of metal hydroxide (8.16 g) and sulfur powder (1.44 g) mixed in advance was used instead of the metal hydroxide.

[0091] Example 6 The coated granular fertilizer (290 g) obtained in Example 1 was charged into a drum-type rolling coating device with a diameter of 300 mm, and the temperature inside the coating device was maintained at 70° C. with a hot air generator while rolling at 25 rpm. Next, a mixture of polyol (0.95 g) and polyisocyanate (0.45 g) that had been preheated to 60° C. was added dropwise into the apparatus through the supply port. Next, after rolling for 60 minutes, the mixture was slowly cooled to room temperature (about 25°C) to obtain a coated fertilizer.

[0092] Example 7 A coated fertilizer was obtained in the same manner as in Example 6, except that the mass ratio of the polyol and polyisocyanate (mass of polyol / mass of polyisocyanate) was changed to 2.10 g / 1.00 g.

[0093] (Comparative Example 5) A coated fertilizer was obtained in the same manner as in Example 6, except that the mass ratio of the polyol and polyisocyanate (mass of polyol / mass of polyisocyanate) was changed to 3.80 g / 1.80 g.

[0094] Example 8 A coated fertilizer was obtained in the same manner as in Example 1, except that Wax 1 was not used.

[0095] Example 9 A coated fertilizer was obtained in the same manner as in Example 1, except that specific fatty acid 2 was used instead of specific fatty acid 1.

[0096] Example 10 In Example 10, coated fertilizer was produced by Method 2 described above, as detailed below. Water-soluble granular fertilizer (250 g) was charged into a drum-type rolling coating device with a diameter of 300 mm, and while rolling at 25 rpm, the temperature inside the coating device was maintained at 70° C. using a hot air generator (step 1). Next, while maintaining the rolling state, specific fatty acid 1 (0.67 g) and metal hydroxide (2.29 g) were prepared, and specific fatty acid 1 was dropped into the device through a supply inlet and rolled for 3 minutes. After that, metal hydroxide was added through a separate supply inlet and the rolling state was maintained for 3 minutes to obtain layer A (step a). Next, while maintaining the rolling state, Wax 1 (0.33 g) was dropped into the device and rolled for 3 minutes, after which metal hydroxide (0.11 g) was fed into the device from another feed port and the rolling state was maintained for 3 minutes to obtain Layer B (step b). Next, the following was counted as one cycle and 13 cycles were repeated. (1 cycle) While maintaining the rolling state, specific fatty acid 1 (0.67 g) was added dropwise from a supply port into the device, and the device was allowed to roll for 3 minutes. After that, metal hydroxide (2.29 g) was added into the device from another supply port, and the device was allowed to roll for 3 minutes to form layer A (step a). Wax 1 (0.33 g) was added dropwise, and the device was allowed to roll for 3 minutes. After that, metal hydroxide (0.11 g) was added into the device from another supply port, and the device was allowed to roll for 3 minutes to form layer B (step b). Next, after rolling for 6 minutes, the mixture was slowly cooled to room temperature (about 25°C) to obtain a coated fertilizer.

[0097] [evaluation] (Measurement of the content of substances with a weight-average molecular weight of 10,000 or more in the coating) Pretreatment The coated fertilizer was crushed, and then the water-soluble components were removed by washing with water, followed by filtration to obtain a water-insoluble portion. The resulting water-insoluble portion was dried in a dryer at 80°C for 24 hours to obtain a measurement sample. The sample was weighed so that the estimated organic content was 1 mg / mL (solvent: 1,2,4-trichlorobenzene), and then dissolved by shaking at 140°C for 1 hour. If any insoluble matter remained in the solution after the shaking dissolution, it was removed by hot filtration using a 0.5 μm sintered filter, and only the soluble portion was used as the test sample. ·measurement HLC-8321GPC / HT (detector: RI) was used, and the column was TSKgel guard column H HR (30) HT x 1, TSKgel GMH HRThe analysis was carried out using three columns of -H(20)HT (manufactured by Tosoh Corporation) and 1,2,4-trichlorobenzene as the eluent at a flow rate of 1.0 ml / min, an injection volume of 0.3 mL, and a column temperature of 140°C. ·Molecular weight analysis Polystyrenes with known molecular weights (15 points in the range of molecular weight = 20,000,000 to 941) were measured in advance, and a calibration curve of molecular weight and retention time was obtained. Thereafter, the test sample was measured, and the relative molecular weight (polystyrene equivalent) was determined from the peak position and retention time of the obtained chromatogram. In the present disclosure, the content of substances having a weight average molecular weight of 10,000 or more was calculated using the following formula. (area of ​​the region in the chromatograph where the molecular weight is 10,000 or more) × 100 / (total peak area in the chromatograph) In addition, when no peak was detected in the region of the chromatograph where the molecular weight was 10,000 or more, it was recorded as "<0.1" in Tables 1 and 2 described later.

[0098] (Measurement of the sulfur atom content in the coating relative to the total content of atoms with atomic numbers from 9 (fluorine) to 92 (uranium) in the periodic table of the elements) The coated fertilizer was crushed, and then the water-soluble components were removed by washing with water, followed by filtration to obtain a water-insoluble portion. The resulting water-insoluble portion was dried in a dryer at 80°C for 24 hours to obtain a measurement sample. The measurement samples were analyzed using an X-ray fluorescence analyzer (Rigaku "Supermini200") to measure the component content of the samples by scanning all elements from atomic number 9 (fluorine) to 92 (uranium) on the periodic table of the elements. The excitation X-ray tube conditions were 50 kV and 4.0 mA. In the present disclosure, the content of sulfur atoms relative to the total content of atoms with atomic numbers 9 (fluorine) to 92 (uranium) in the periodic table of the elements in the coating (also referred to as the "sulfur atom content") was calculated using the following formula. (Sulfur atom content in the coating) x 100 / (total content of atoms in the coating with atomic numbers 9 (fluorine) to 92 (uranium) in the periodic table of the elements) When the sulfur atom content is less than 1 mass %, it is indicated as "<1" in Tables 1 and 2 below. When the sulfur atom content is more than 99 mass %, it is indicated as ">99" in Tables 1 and 2 below.

[0099] (average coating thickness) The thickness of the coating was measured by observing the cross section of the coated fertilizer using a scanning electron microscope (SU8010 manufactured by Hitachi), measuring the thickness of the coating at any five points, and calculating the average value (arithmetic mean value).

[0100] (Preparing the shells) An accelerated test was conducted in which the coated fertilizer was kept in water at 60°C for 17 days to dissolve the water-soluble fertilizer components.The fertilizer was then removed from the water and water droplets on the surface were removed to obtain shells (particles made of a coating) containing water inside. Furthermore, the shells containing water inside (particles made of a coating) were dried in a dryer at 60° C. for 72 hours to obtain shells containing no water inside (particles made of a coating).

[0101] (Measurement of average crushing load) The compressive fracture strength of the shells was measured using a digital force gauge (Imada, model number ZP-500N) and an electric test stand (Imada, model MX-500N) at a descending speed of 20 mm / min. The first fracture point was taken as the measurement result, and the above measurement was performed on 30 randomly selected shells, and the average crushing load (arithmetic mean value) was calculated. The above evaluation was performed on both shells containing water and shells without water. The average crushing load was rated as acceptable if it was 0.7 N or less. The smaller the average crushing load, the easier it is to disintegrate after the fertilizer components have been dissolved, which is preferable.

[0102] (Confirmation of sinking and floating of the sample in water after crushing) For the shells not containing water inside, samples were collected after the above (measurement of the average crushing load). The samples after the above (measurement of the average crushing load) were considered to be samples that had undergone a simulated disintegration process. In other words, the compressive load in the above (measurement of the average crushing load) was considered to be an external force that could cause the shells to collapse. Note that, although all of the crushed samples in Comparative Example 3 had cracks, they maintained their shell shape. Of the crushed samples in Comparative Example 5, 11 out of 30 had cracks but maintained their shell shape, and the rest were shells that had collapsed into fragments (fragments). All of the crushed samples in the other experimental examples were shells that had collapsed into fragments (fragments). In addition, the mass of the shell before crushing was measured, and if fragments formed after crushing, the mass of the largest fragment was measured and the ratio of the mass of the largest fragment to the mass of the shell before crushing was calculated (referred to as "fragment mass ratio" in the table). Note that if the fragment mass ratio was more than 50 mass%, it was determined that the shell shape was maintained after crushing. The sample was then placed in a 100 ml clear wide-mouth bottle (inner mouth diameter: φ32 mm) with 50 ml of water, sealed, and stirred at 100 rpm for 5 minutes using a tabletop pot mill stand (manufactured by AS ONE Corporation, product number: PM-001). The sample was then checked for whether it would settle or float in the water. The sedimentation of the fragmented shells (fragments) was assessed by stirring the shells under a specified load in water, allowing them to stand for 1 minute until the surface layer settled, and then visually observing the surface of the water. If no floating material was observed, the sample was scored as "settling," and if floating material was observed, the sample was scored as "not settling."

[0103] (Number of cracks after mechanical fertilization) Mechanical fertilization was carried out under the conditions below (samples after fertilization were collected at the drop outlet), and the appearance of the 100 samples obtained was observed, and the number of samples with cracks on the surface (referred to as the "number of cracks after mechanical fertilization") was counted. (Conditions for mechanical fertilization) Using a side row fertilizer rice transplanter (EP6D; manufactured by Kubota Corporation) adjusted to apply a fertilizer rate of 5 kg / 10 a, 100 g of coated fertilizer was put into the hopper and collected from the drop outlet. The collected coated fertilizers (100 pieces) were immersed in a red ink solution for 3 minutes to color the cracked areas of the coated fertilizer, and then observed under an optical microscope. Pieces with 15 or fewer cracks out of 100 were considered to be pass-grade. The fewer cracks found, the better, as they are more resistant to mechanical fertilization.

[0104] The results are shown in Tables 1 and 2 below.

[0105] [Table 1]

[0106] [Table 2]

[0107] From the above results, it was found that the coated fertilizers of the examples contain a coating that exhibits a good balance of the following: strength sufficient to withstand mechanical fertilization; the shells easily disintegrate under low load after the fertilizing ingredients have been eluted (whether the shells contain water inside or do not contain water inside); and the shells easily settle in water in paddy fields, etc. after disintegration. [Industrial Applicability]

[0108] According to the present disclosure, it is possible to provide a method for using a coated fertilizer containing a coating that exhibits a good balance of the following characteristics: strength sufficient to withstand mechanical fertilization; the shells easily disintegrating under low load after the fertilizing components have been eluted; and the shells easily settling in water such as in a paddy field after disintegration; and a method for producing shell fragments.

[0109] Although the present disclosure has been described in detail and with reference to specific embodiments, it will be apparent to those skilled in the art that various changes and modifications can be made without departing from the spirit and scope of the disclosure.

Claims

1. A method for using a coated fertilizer comprising a water-soluble granular fertilizer and a coating covering the water-soluble granular fertilizer, a fertilization step of mechanically applying the coated fertilizer; a dissolution step in which water-soluble fertilizer components are dissolved from the coated fertilizer after the fertilization step; a disintegration step of applying a load to the shell derived from the coating obtained after the elution step to generate fragments of the shell; and The coated fertilizer has a content of a substance having a weight-average molecular weight of 10,000 or more in the coating of 0 to 10%, and A method for using a coated fertilizer, wherein the content of sulfur atoms in the coating is 0 to 11 mass% relative to the total content of atoms with atomic numbers 9 (fluorine) to 92 (uranium) in the periodic table of the elements.

2. 2. The method for using the coated fertilizer according to claim 1, wherein the coated fertilizer has an average crushing load of 0.5 N or less, the particles being obtained by replacing the water-soluble granular fertilizer contained in the coated fertilizer with water.

3. 2. The method for using the coated fertilizer according to claim 1, wherein, after mechanical fertilization under the following conditions is performed for 100 coated fertilizers, cracks are generated on the surface of 15 or less coated fertilizers. (Conditions for mechanical fertilization) Using a side row fertilizer rice transplanter adjusted to apply a fertilizer amount of 5 kg / 10 a, 100 g of the coated fertilizer was put into the hopper, and the coated fertilizer was collected from the drop outlet.

4. The method for using the coated fertilizer according to claim 1 , wherein a load of 0.5 N or more is applied to the shell derived from the coating in the disintegrating step.

5. 2. The method for using the coated fertilizer according to claim 1, wherein the content of the substance having a weight-average molecular weight of 10,000 or more in the coating is 0 to 7%.

6. 2. The method for using the coated fertilizer according to claim 1, wherein the content of the substance having a weight-average molecular weight of 10,000 or more in the coating is 0 to 3%.

7. 2. The method for using the coated fertilizer according to claim 1, wherein the content of the substance having a weight-average molecular weight of 10,000 or more in the coating is 0 to 1%.

8. 2. The method for using the coated fertilizer according to claim 1, wherein the coating is substantially free of substances having a weight average molecular weight of 10,000 or more.

9. 6. The method for using the coated fertilizer according to claim 1 or 5, wherein the content of sulfur atoms in the coating is 0 to 9 mass% relative to the total content of atoms having atomic numbers 9 (fluorine) to 92 (uranium) in the periodic table of the elements.

10. 6. The method for using the coated fertilizer according to claim 1 or 5, wherein the content of sulfur atoms in the coating is 0 to 5 mass% relative to the total content of atoms with atomic numbers 9 (fluorine) to 92 (uranium) in the periodic table of the elements.

11. 6. The method for using the coated fertilizer according to claim 1 or 5, wherein the content of sulfur atoms in the coating is 0 to 2 mass% relative to the total content of atoms with atomic numbers 9 (fluorine) to 92 (uranium) in the periodic table of the elements.

12. 6. The method for using the coated fertilizer according to claim 1 or 5, wherein the coating is substantially free of sulfur atoms.

13. a step of preparing a coated fertilizer comprising a water-soluble granular fertilizer and a coating covering the water-soluble granular fertilizer, wherein the content of a substance having a weight-average molecular weight of 10,000 or more in the coating is 0 to 10% and the content of sulfur atoms in the coating relative to the total content of atoms with atomic numbers 9 (fluorine) to 92 (uranium) in the periodic table of the elements is 0 to 11% by mass; A step in which the water-soluble granular fertilizer is dissolved from the coated fertilizer to form a shell derived from the coating; disintegrating the shells to form shell fragments; A method for producing shell fragments derived from the coated fertilizer, comprising:

14. 14. The method of claim 13, wherein forming the shell fragments occurs by at least one of soil compaction, soil repression, and soil tillage.

15. 2. The method for using a coated fertilizer according to claim 1, wherein the mass of the largest fragment among the fragments generated in the disintegrating step is 50% or less of the mass of the shell before the load is applied.

16. The method for producing shell fragments according to claim 13, wherein the mass of the largest fragment formed in the step of forming shell fragments is 50% or less of the mass of the shell before being disintegrated.

17. The method for producing shell fragments according to claim 13, wherein the shell fragments have sedimentation properties in water.

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