Coated Granular Fertilizer

Abstract

It has been found that coated granular fertilizers having a coating containing hardened vegetable oil may have a problem in that the fertilizer components may be prematurely dissolved after storage. An object of the present invention is to provide a coated granular fertilizer that is degradable and inhibits the premature dissolution of the fertilizer components after storage. [Solution] A coated granular fertilizer comprising granular urea and a coating that coats the granular urea, the coating containing hardened vegetable oil, the melting point of the hardened vegetable oil being 60°C or higher and 100°C or lower, and the peak intensity ratio (peak intensity at 17 Å / peak intensity at 4.0 Å) in an X-ray diffraction measurement of the coating being 1.2 or higher.

Description

[Technical field]

[0001] The present invention relates to a coated granular fertilizer. [Background technology]

[0002] Coated granular fertilizers have the advantage that they can control the elution of fertilizer components and maintain their effectiveness after being spread once, thereby reducing the number of times they need to be spread.

[0003] For example, Patent Document 1 describes a coated granular fertilizer that includes a resin coating layer provided on the surface of granular urea and a protective layer containing hardened vegetable oil provided on the outside of the resin coating layer. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2011-195427 A Summary of the Invention [Problem to be solved by the invention]

[0005] The present inventors have found that a coated granular fertilizer having a coating containing hardened vegetable oil may have a problem that fertilizer components may dissolve earlier after storage. An object of the present invention is to provide a coated granular fertilizer that is degradable and inhibits early dissolution of fertilizer components after storage. [Means for solving the problem]

[0006] The present inventors have found that the above-mentioned problems can be solved by setting the peak intensity ratio in X-ray diffraction measurement of a coating of a coated granular fertilizer having a coating containing hydrogenated vegetable oil, more specifically, the peak intensity of 17 Å / peak intensity of 4.0 Å or the peak intensity of 17 Å / peak intensity of 4.5 Å, within a specific range.

[0007] That is, the coated granular fertilizer according to the present invention may have the following configuration aspects, but is not limited thereto. [1] The present invention provides a method for producing a urea-based food product comprising: The coating comprises hydrogenated vegetable oil, The melting point of the hardened vegetable oil is 60°C or higher and 100°C or lower, The coated granular fertilizer has a peak intensity ratio (peak intensity at 17 Å / peak intensity at 4.0 Å) of 1.2 or more in X-ray diffraction measurement of the coating. [2] The present invention provides a method for producing a urea-based food product comprising: The coating comprises hydrogenated vegetable oil, The melting point of the hardened vegetable oil is 60°C or higher and 100°C or lower, The coated granular fertilizer has a peak intensity ratio (peak intensity at 17 Å / peak intensity at 4.5 Å) of 1.5 or more in X-ray diffraction measurement of the coating. [3] The coated granular fertilizer according to [1] or [2], wherein the hydrogenated vegetable oil is at least one selected from the group consisting of hydrogenated castor oil, hydrogenated rapeseed oil, and hydrogenated soybean oil. [4] The coated granular fertilizer according to [1] or [2], wherein the hydrogenated vegetable oil is hydrogenated castor oil. Effect of the Invention

[0008] According to the present invention, it is possible to provide a coated granular fertilizer which is degradable and in which the early elution of fertilizer components after storage is suppressed. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] The coated granular fertilizer according to the present invention will now be described.

[0010] The coated granular fertilizer comprises granular urea and a coating that coats the granular urea.

[0011] The coated granular fertilizer comprises granular urea.

[0012] The granular urea is a granular material containing a urea component. The granular urea may be a granular material in which the urea component is granulated alone, or may be a granular material containing the urea component and any additive. Examples of the optional additives include a floating inhibitor, a composition uniformity promoter, an effect development promoter, a colorant, and a granulation promoter.

[0013] The particle size of the granular urea is not particularly limited and is usually 0.1 to 15.0 mm.

[0014] The granular urea can be produced by a known method. The granular urea can be produced by granulating the urea component alone, or by mixing the urea component with the optional additives and granulating the mixture.

[0015] The coating comprises hydrogenated vegetable oil.

[0016] The hydrogenated vegetable oil can be obtained by adding hydrogen to a naturally occurring or synthetic vegetable oil containing unsaturated fatty acid triglycerides to saturate the unsaturated bonds of the unsaturated fatty acid triglycerides. The hydrogenated vegetable oil can also be obtained by chemical synthesis. Examples of the hydrogenated vegetable oil include castor oil, rapeseed oil, soybean oil, palm oil, peanut oil, jojoba oil, cottonseed oil, and coconut oil.

[0017] The hydrogenated vegetable oil has a suitable decomposition property in a fertilization environment such as soil. Specifically, the hydrogenated vegetable oil is not immediately decomposed in the fertilization environment, so that the coating can exert a dissolution control property. Furthermore, the hydrogenated vegetable oil is decomposed at a suitable rate so that the remaining in the fertilization environment is not a problem. In other words, the coated granular fertilizer having a coating containing the hydrogenated vegetable oil has both excellent decomposition property and dissolution control property. The decomposition property of the hydrogenated vegetable oil can be measured according to the procedure described in the Examples section below.

[0018] The hydrogenated vegetable oil is solid at 25°C. The melting point of the hydrogenated vegetable oil is 60°C or higher and 100°C or lower, and may be 80°C or higher and 90°C or lower. Hydrogenated vegetable oils with such melting points can be melted by heating and therefore can be handled in a liquid state without using a solvent. Furthermore, when hydrogenated vegetable oils with such melting points are used, adhesion between the coated granular fertilizers or between the coated granular fertilizers and the rotating tank during production of the coated granular fertilizer can be prevented, improving the manufacturability of the coated granular fertilizer. The manufacturability of the coated granular fertilizer can be measured according to the procedure described in the Examples section below. The freezing point of the hydrogenated vegetable oil is from 60° C. to 100° C., and may be from 80° C. to 90° C. In general, the melting point and the freezing point are the same value, but in the case of the hydrogenated vegetable oil, the melting point may be higher than the freezing point.

[0019] The hardened vegetable oil has low adhesion. By including hardened vegetable oil having low adhesion in the coating of the coated granular fertilizer, the caking of the coated granular fertilizer with each other during production and storage can be suppressed, and the adhesion of the coated granular fertilizer is improved. The adhesion of the coated granular fertilizer during storage can be measured according to the procedure described in the Examples section below.

[0020] The hydrogenated vegetable oil has a lower water vapor permeability than the biodegradable resin, and is therefore superior in terms of improving the controllability of the elution of fertilizer components. The hydrogenated vegetable oil has a higher fluidity when melted by heating than the biodegradable resin, and therefore is less likely to caking during the production of the coated granular fertilizer, and the manufacturability of the coated granular fertilizer is improved.

[0021] The content of the hardened vegetable oil in the coating may be 60% by mass or more, 70% by mass or more, 80% by mass or more, 90% by mass or more, or 95% by mass or more.

[0022] The coating may contain only one of the hydrogenated vegetable oils or may contain two or more of the hydrogenated vegetable oils. The coating may contain at least one selected from the group consisting of hydrogenated castor oil, hydrogenated rapeseed oil, and hydrogenated soybean oil.

[0023] The coated granular fertilizer preferably does not contain a biodegradable resin. Examples of the biodegradable resin include polylactic acid, polyhydroxyalkanoate, polybutylene adipate terephthalate, polycaprolactone, polybutylene succinate, polyethylene succinate, polyvinyl alcohol, polyglycolic acid, polyaspartic acid, cellulose fatty acid ester, and polybutylene succinate adipate.

[0024] The coating preferably does not contain a resin that is not decomposable. Examples of the resin that is not decomposable include thermoplastic resins and thermosetting resins. Examples of the thermoplastic resins include olefin resins, diene resins, and polyvinyl chloride. Examples of the olefin resins include polyethylene, polypropylene, polybutene, polystyrene, ethylene-propylene copolymers, butene-ethylene copolymers, butene-propylene copolymers, ethylene-vinyl acetate copolymers, ethylene-acrylic acid copolymers, ethylene-acrylic acid ester copolymers, ethylene-methacrylic acid copolymers, ethylene-methacrylic acid ester copolymers, and ethylene-carbon monoxide copolymers. Examples of the diene resins include butadiene copolymers, isoprene polymers, chloroprene polymers, butadiene-styrene copolymers, and styrene-isoprene copolymers. Examples of the thermosetting resins include epoxy resins, alkyd resins, phenolic resins, urea resins, melamine resins, and silicone resins.

[0025] The coating may contain an optional additive. For example, an antibacterial agent may be mentioned as the optional additive. The content of the optional additive in the coating is, for example, 0.1 to 10% by mass.

[0026] The mass ratio of the granular fertilizer to the coating may be 1:0.1 or more and 1:0.5 or less.

[0027] The thickness of the coating is usually 30 to 500 μm. The thickness of the coating can be measured by observing a cross section passing through the center of the coated granular fertilizer using a scanning electron microscope (SU-3800, manufactured by Hitachi High-Technologies Corporation) in BSE mode. The thickness of the coating can be determined by drawing 10 line segments perpendicular to the coating for the coated granular fertilizer and averaging the lengths of these lines.

[0028] The method for producing the coated granular fertilizer includes a first step of bringing the granular urea into a rolling state, a second step of adding the hardened vegetable oil to the granular urea in the rolling state, and a third step of cooling the obtained coated granular fertilizer.

[0029] In the first step, the granular urea in the rolling state may be heated. The heating temperature of the granular urea may be 50°C or more and 120°C or less, or 70°C or more and 100°C or less.

[0030] In the second step, the hardened vegetable oil may be melted by heating. The temperature of the heat melting is higher than the melting point of the hardened vegetable oil, and may be 70°C, 80°C, 90°C, or 105°C.

[0031] In the third step, the coated granular fertilizer may be in a rolling state or may be left stationary. The cooling rate of the coated granular fertilizer in the third step (hereinafter referred to as the cooling rate) may be 0.1 to 8.0°C / min, 0.1 to 5.0°C / min, or 0.3 to 3.0°C / min. The third step may be carried out by allowing the coated granular fertilizer to cool at room temperature, or by blowing a gas onto the coated granular fertilizer, or by cooling the coated granular fertilizer using a water bath, an ice-water bath, an ice bath, or an oil bath set to an arbitrary temperature.

[0032] In the first step, the heating temperature of the granular urea may be lower than the melting point or freezing point of the hardened vegetable oil, or may be higher than the melting point or freezing point of the hardened vegetable oil. The heating temperature of the granular urea is preferably lower than the melting point or freezing point of the hardened vegetable oil. The difference between the melting point or solidification point of the hydrogenated vegetable oil and the heating temperature of the granular urea may be 25° C. or less, 20° C. or less, or 10° C. or less. When the difference between the melting point or solidification point of the hydrogenated vegetable oil and the heating temperature of the granular urea is within this range, it is believed that the hydrogenated vegetable oil can be prevented from being excessively cooled by the granular urea in the second step. The difference between the heating temperature of the granular urea in the first step and the heat-melting temperature in the second step may be 50° C. or less, 35° C. or less, or 25° C. or less. By having the difference between the heating temperature of the granular urea and the heat-melting temperature within this range, it is believed that the vegetable hardened oil can be prevented from being excessively cooled by the granular urea in the second step.

[0033] The method for producing the coated granular fertilizer may include a step of adding a lubricant such as liquid paraffin or other optional components between the first step and the second step. The step of adding other optional components may be a step carried out under heating conditions. The method for producing the coated granular fertilizer may include a step of adding an optional additive such as a surfactant or an anti-caking agent to the surface of the obtained coated granular fertilizer after the third step.

[0034] The crystal structure of the coating of the coated granular fertilizer can be analyzed by X-ray diffraction measurement. The diffraction conditions for the X-ray diffraction measurement are given by Bragg's equation (2dsinθ=nλ(n=1,2,3...)). Here, d is the lattice constant, θ is the angle of incidence, λ is the wavelength of the X-ray, and n is a natural number. In the X-ray diffraction measurement, a diffraction peak is observed at an angle of incidence θ that satisfies the Bragg's equation. The XRD peak intensity ratio of the coating of the coated granular fertilizer can be measured according to the procedure described in the Examples section below.

[0035] The coating of the coated granular fertilizer exhibits peaks at least at d=4.0(±0.2) Å, 4.5(±0.2) Å, 6.3(±0.2) Å and 17(±0.2) Å in X-ray diffraction measurement. The value obtained by dividing the peak intensity at d = 17 (±0.2) Å of the coating of the coated granular fertilizer by the peak intensity at d = 4.0 (±0.2) Å (hereinafter, may be expressed as peak intensity at 17 Å / peak intensity at 4.0 Å) may be 1.0 or more, 1.2 or more, 1.2 or more and 10 or less, 1.2 or more and 5.0 or less, 1.2 or more and 4.0 or less, or 1.2 or more and 3.0 or less. The value obtained by dividing the peak intensity at d = 17 (±0.2) Å of the coating of the coated granular fertilizer by the peak intensity at d = 4.5 (±0.2) Å (hereinafter, may be expressed as peak intensity at 17 Å / peak intensity at 4.5 Å) may be 1.0 or more, 1.5 or more, 1.5 or more and 10 or less, 1.5 or more and 5.0 or less, 1.5 or more and 7.0 or less, or 1.5 or more and 4.0 or less.

[0036] The coated granular fertilizer can be used for growing crops in paddy fields, such as growing grass crops. The coated granular fertilizer can be applied to paddy fields alone or as a mixed fertilizer with other fertilizers.

[0037] In this specification, the dissolution rate E1 of the fertilizer components when the coated granular fertilizer is left standing in water at a concentration of 2.5 g / 100 mL (25° C., 2 weeks) is referred to as the dissolution rate. The dissolution rate can be measured according to the procedure described in the Examples section below. The dissolution controllability of the coated granular fertilizer can be evaluated based on the value of E1. In this specification, the dissolution rate E2 of the fertilizer components when the coated granular fertilizer is left standing in a thermostatic chamber set at 54°C for 2 weeks and then left standing in water at a concentration of 2.5 g / 100 mL (25°C, 2 weeks) is referred to as the dissolution rate after storage. Standing at 54°C for 2 weeks is a test condition equivalent to standing at room temperature for approximately 2 years. The dissolution rate after storage can be measured according to the procedure described in the Examples section below. The storage stability of the coated granular fertilizer can be evaluated based on the value of E2-E1.

[0038] The coated granular fertilizer can be applied to the soil using a spreader such as a side stripe applicator. EXAMPLES

[0039] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to the following examples.

[0040] [Granular urea] Granular urea (manufactured by China BlueChemical Limited, particle size: approx. 3mm) [Vegetable hydrogenated oil] "Hydrogenated Castor Oil" manufactured by Ito Oil Mills, melting point 80-90°C (hereinafter referred to as "hydrogenated castor oil 1") "Super hardened rapeseed oil" manufactured by Yokoseki Oil Industries Co., Ltd., melting point 67°C (hereinafter referred to as "super hardened rapeseed oil") [Petroleum wax] "HNP-51" manufactured by Nippon Seiro Co., Ltd. (hereinafter referred to as paraffin wax) "Sasol C80" manufactured by Kato Yoko Co., Ltd. (hereinafter referred to as FT Wax) [Plant-based wax] "Refined Carnauba Wax No. 2" manufactured by Kato Yoko Co., Ltd. (hereinafter referred to as "Carnauba Wax") "Refined Candelilla Wax" manufactured by Kato Yoko Co., Ltd. (hereinafter referred to as Candelilla Wax) [others] "Lunac S-98" manufactured by Kao Chemical Corporation (hereinafter referred to as stearic acid) "Nissan Electol WEP-5" manufactured by NOF Corporation (hereinafter referred to as fatty acid ester) "Kalcol 220-80" manufactured by Kao Chemical Corporation (hereinafter referred to as behenyl alcohol)

[0041] [Example 1] Granular urea 1 (1,000 parts by mass) was placed in a rotating tank and kept in a tumbling state. The granular urea was heated to approximately 70°C with hot air, after which liquid paraffin (MORESCO White P-350P, manufactured by MORESCO Corporation) (10 parts by mass) was added and the tumbling state was continued for 5 minutes. The paraffin-coated granular urea was kept in a rolling state, and hardened castor oil 1 (210 parts by mass) that had been heated and melted at 105° C. was added, and the rolling state was maintained under heating conditions for 3 minutes or more. Thereafter, the mixture was cooled to about room temperature at a cooling rate of 0.4° C. / min to obtain a coated granular fertilizer (hereinafter, referred to as this coated granular fertilizer 1).

[0042] [Example 2] A coated granular fertilizer was obtained in the same manner as in Example 1, except that the cooling rate was set to 1.6° C. / min (hereinafter, referred to as this coated granular fertilizer 2).

[0043] [Example 3] A coated granular fertilizer was obtained in the same manner as in Example 1, except that the cooling rate was set to 2.8° C. / min (hereinafter, referred to as this coated granular fertilizer 3).

[0044] [Comparative Example 1] A coated granular fertilizer was obtained in the same manner as in Example 1, except that the cooling rate was set to 9.0° C. / min (hereinafter, referred to as comparative coated granular fertilizer 1).

[0045] [Comparative Examples 2 to 3] Coated granular fertilizers were obtained in the same manner as in Example 2, except that paraffin wax or stearic acid was used instead of hardened castor oil 1, and the heating temperature of the granular urea was set to 55°C (hereinafter, these are referred to as comparative coated granular fertilizers 2 and 3, respectively).

[0046] [Comparative Examples 4 to 5] Coated granular fertilizers were obtained in the same manner as in Example 2, except that FT wax or carnauba wax was used instead of castor hardened oil 1 and the heating temperature of the granular urea was set to 55°C (hereinafter, these are referred to as comparative coated granular fertilizers 4 and 5, respectively).

[0047] [Evaluation of decomposition of vegetable hardened oils, petroleum waxes, etc.] (How to prepare evaluation samples) 10 g of samples of the hydrogenated vegetable oils and petroleum waxes shown in Table 1 were placed in a thermostat set at 105°C and melted. The molten samples were cast onto a glass plate using a film applicator (Allgood Corporation, gap 600 μm), and cooled and solidified at room temperature to create a film with a thickness of approximately 300 μm. (Evaluation method) 20 g of soil (collection location: Kasai City, Hyogo Prefecture) was placed in a plastic cup (50 mL). The prepared film was cut into 2 cm square pieces of approximately 100 mg to prepare test pieces and weighed (M1). The test pieces were placed on the soil, and 20 g of soil was added from above. The test pieces were then lightly slammed on the ground about 10 times and packed. The plastic cups and a cup of water for moisturizing were arranged on a tray, placed in a vinyl bag, and the top was lightly tied. The cups were placed in a thermostatic chamber set at 28°C, and the weight of the cup was measured every two weeks from the start of the test, and water was added with a spray bottle if any change was observed. After one month, the test pieces were collected, lightly washed, and thoroughly dried at room temperature for at least one night. The mass of the test pieces was measured (M2), and the mass loss rate (W = M2 / M1 x 100 (%)) was calculated. (Evaluation Criteria) A: Mass reduction rate W is 20% or more and less than 40% B: Mass reduction rate W is 10% or more and less than 20% or 40% or more and less than 60% C: Mass reduction rate W is less than 10% or 60% or more When the rating is A, the decomposition property of the coating of the coated granular fertilizer is evaluated as good. The results are shown in Table 1.

[0048] [Table 1]

[0049] [Evaluation of the manufacturability of coated granular fertilizer] (Evaluation method) The degree of adhesion between the coated granular fertilizers or between the coated granular fertilizers and the rotating drum during the production of the present coated granular fertilizers 1 to 3 and the comparative coated granular fertilizers 1 to 5 was visually evaluated. The results are shown in Tables 2 and 4. (Evaluation Criteria) ◯: Almost no sticking occurred between the coated granular fertilizer particles or between the coated granular fertilizer and the rotating drum. ×: Significant sticking occurred between the coated granular fertilizer particles or between the coated granular fertilizer and the rotating tank.

[0050] [Table 2]

[0051] [Evaluation of adhesion of coated granular fertilizer during storage] (Evaluation method) 50 g of the present coated granular fertilizer 1 was placed in a cylindrical container, and a 5 kg weight was placed on top of it and left to stand for 24 hours in a thermostat set at 40°C. After that, the present coated granular fertilizer 1 was removed from the container and the degree of adhesion between the present coated granular fertilizers 1 was visually evaluated. The results are shown in Table 3. (Evaluation Criteria) ◯: There was almost no adhesion between the coated granular fertilizer particles. ×: Significant adhesion occurred between the coated granular fertilizers.

[0052] [Table 3]

[0053] [Elution rate] 2.5 g of the present coated granular fertilizer 1 (60 to 80 granules) was placed in a sample bottle, 100 mL of water was added, and the bottle was allowed to stand at 25°C. After 14 days, 0.6 mL of water was collected from the sample bottle, and the urea concentration was measured using an ultraviolet-visible spectrophotometer (UV-1900i, Shimadzu Corporation). Based on the measured urea concentration, the elution rate E1 (%) of urea from the present coated granular fertilizer 1 was calculated. The elution rates of the present coated granular fertilizers 2 to 3 and the comparative coated granular fertilizer 1 were also evaluated in the same manner. The results are shown in Table 4. (Evaluation Criteria) A: Dissolution rate E1 is less than 20% B: Dissolution rate E1 is 20% or more and less than 35% C: Dissolution rate E1 is 35% or more When the evaluation is A or B, the dissolution controllability can be evaluated as being good.

[0054] [Storage stability] 2.5 g of the present coated granular fertilizer 1 (60 to 80 granules) was placed in a sample bottle and allowed to stand for 2 weeks in a thermostatic chamber set at 54°C. Then, 100 mL of water was added and allowed to stand at 25°C. After 14 days, 0.6 mL of water was collected from the sample bottle and the urea concentration was measured using an ultraviolet-visible spectrophotometer (UV-1900i, Shimadzu Corporation). Based on the measured urea concentration, the dissolution rate E2 (%) of the present coated granular fertilizer 1 after storage was calculated. The dissolution rates after storage of the present coated granular fertilizers 2 to 3 and the comparative coated granular fertilizer 1 were also evaluated in the same manner. The results are shown in Table 4. (Evaluation Criteria) A: E2-E1 is less than 5% B: E2-E1 is 5% or more but less than 10% C: E2-E1 is 10% or more When the evaluation is A or B, the storage stability can be evaluated as good.

[0055] [Evaluation of the coating XRD peak intensity ratio of coated granular fertilizer] The coating of the present coated granular fertilizer 1 (about 100 g) was scratched with a cutter knife and immersed in water overnight to dissolve the fertilizer components. After that, it was thoroughly air-dried at room temperature, and the obtained coating was ground in a mortar to obtain a powdered coating sample. Using an XRD (tabletop XRD device D2 Phaser, manufactured by BRUKER), measurements were performed using CuKα (λ=1.542 Å) as a radiation source under conditions of output of 0.3 kW, scanning angle 2θ=2.0-30.0°, and measurement speed of 2° / min, to obtain a diffraction pattern of the powdered coating sample. The peak intensity ratios (peak intensity at 17 Å / peak intensity at 4.0 Å) and peak intensity ratios (peak intensity at 17 Å / peak intensity at 4.0 Å) of the present coated granular fertilizers 1-3 and the comparative coated granular fertilizer 1 are shown in Table 4. In this specification, peak intensity refers to the peak height (count per second) in X-ray diffraction measurement.

[0056] [Table 4]

Claims

1. The present invention provides a method for producing a urea-based food product comprising: The coating comprises hydrogenated vegetable oil, The melting point of the hardened vegetable oil is 60° C. or more and 100° C. or less, The coated granular fertilizer has a peak intensity ratio (peak intensity at 17 Å / peak intensity at 4.0 Å) of 1.2 or more in X-ray diffraction measurement of the coating.

2. The present invention provides a method for producing a urea-based food product comprising: The coating comprises hydrogenated vegetable oil, The melting point of the hardened vegetable oil is 60° C. or more and 100° C. or less, The coated granular fertilizer has a peak intensity ratio (peak intensity at 17 Å / peak intensity at 4.5 Å) of 1.5 or more in X-ray diffraction measurement of the coating.

3. 3. The coated granular fertilizer according to claim 1, wherein the hydrogenated vegetable oil is at least one selected from the group consisting of hydrogenated castor oil, hydrogenated rapeseed oil and hydrogenated soybean oil.

4. 3. The coated granular fertilizer according to claim 1, wherein the hydrogenated vegetable oil is hydrogenated castor oil.

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