Coated Granular Fertilizer

Abstract

An object of the present invention is to provide a coated granular fertilizer which is degradable and has improved manufacturability, release controllability, and adhesion during storage. [Solution] The inventors conducted extensive research to develop a coated granular fertilizer with improved degradability, manufacturability, elution controllability, and adhesion during storage, and discovered that by using a hydrogenated vegetable oil with an iodine value within a specific range as the coating of the coated granular fertilizer, it is possible to simultaneously satisfy all four characteristics, thereby completing the present invention.

Description

[Technical field]

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

[0002] Coated granular fertilizers have the advantage that the elution of fertilizer components is controlled and their effectiveness can be sustained after one application, thereby reducing the number of times the fertilizer needs to be applied.

[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] An object of the present invention is to provide a coated granular fertilizer which is degradable and has improved manufacturability, release controllability, and adhesion during storage. [Means for solving the problem]

[0006] The present inventors conducted extensive research to develop a coated granular fertilizer with improved decomposition properties, manufacturability, release controllability, and adhesion during storage, and discovered that the four properties can be satisfied simultaneously by using a hydrogenated vegetable oil having an iodine value within a specific range as the coating of the coated granular fertilizer, thereby completing the present invention.

[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 iodine value (gI 2 / 100g) is 35 or less. [2] The hardness of the hydrogenated vegetable oil (gf / mm 2 ) is 10 or more. [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 that is degradable and has improved manufacturability, release controllability, and adhesion during storage. 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 an iodine value (gI 2 / 100 g) is 35 or less, may be 25 or less, may be 1 to 25 or may be 3 to 20. The iodine value of the hydrogenated vegetable oil can be measured according to the procedure described in the Examples section below.

[0018] The hardness of the hydrogenated vegetable oil (gf / mm 2 ) may be 10 or more, or may be 20 or more. The upper limit of the hardness of the hydrogenated vegetable oil is not particularly limited, but may be 100 or less, or may be 60 or less. The hardness of the hydrogenated vegetable oil can be measured according to the procedure described in the Examples section below.

[0019] The hydrogenated vegetable oil has a suitable decomposition property in a fertilization environment such as soil. The hydrogenated vegetable oil has a structure similar to that of animal and vegetable fats, and is considered to be decomposed by fat-decomposing bacteria that are widely present in natural environments. Specifically, the hydrogenated vegetable oil is not immediately decomposed in a fertilization environment, so that the coating can exhibit elution controllability. Furthermore, the hydrogenated vegetable oil is decomposed at a suitable rate such that the remaining of the hydrogenated vegetable oil in the fertilization environment is not a problem. In other words, the coated granular fertilizer having a coating containing the hydrogenated vegetable oil is excellent in both decomposition property and elution controllability. The decomposition property of the hydrogenated vegetable oil can be measured according to the procedure described in the Examples section below.

[0020] 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. The mechanism by which the coated granular fertilizer has good manufacturability is not completely clear, and various factors are thought to be involved, but the following mechanism is thought to be one of the contributing factors. Since the iodine value of the hardened vegetable oil contained in the coating is within a specific range, the coated granular fertilizer has low adhesion, and is less likely to stick to the rotating drum during production. This is thought to result in good manufacturability of the coated granular fertilizer.

[0021] 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.

[0022] 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.

[0023] 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.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] The mass ratio of the granular fertilizer to the coating may be 1:0.1 or more and 1:0.5 or less.

[0029] 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.

[0030] The method for producing the coated granular fertilizer includes a first step of rolling the granular urea, and a second step of adding the hardened vegetable oil to the rolling granular urea. In the second step, the hardened vegetable oil can be added to the granular urea after dissolving it in a solvent or after melting the hardened vegetable oil by heating. The method of adding the melted hardened vegetable oil to the granular urea is preferable from the viewpoint of reducing the environmental load because it does not use a solvent. The temperature for 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] 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.

[0032] 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.

[0033] In this specification, the dissolution rate E1 of the fertilizer components when the coated granular fertilizer is left to stand in water for 21 days at a concentration of 2.5 g / 100 mL 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.

[0034] The coated granular fertilizer has good release controllability. The mechanism by which the coated granular fertilizer has good release controllability has not been fully elucidated, and various factors are thought to be involved, but the following mechanism is thought to be one of the contributing factors. When the iodine value of the hardened vegetable oil is within a specific range, the adhesion of the hardened vegetable oil becomes moderate, and as a result, the coating is less likely to be damaged by contact between the coated granular fertilizers during production of the coated granular fertilizer, and a coating without defects is formed, which is thought to result in good release controllability of the coated granular fertilizer.

[0035] The coated granular fertilizer can be applied to the soil using a spreader such as a side stripe applicator.

[0036] In this specification, the elution rate E2 of the fertilizer components when the coated granular fertilizer is spread using a side stripe fertilizer applicator (YK6D, manufactured by Yanmar Co., Ltd.) and then quickly collected and allowed to stand in water for 21 days in the same manner as above is referred to as the elution rate after mechanical fertilization. E2 of the coated granular fertilizer can be measured according to the procedure described in the Examples section below. The impact resistance of the coated granular fertilizer can be evaluated based on the value of E2-E1. EXAMPLES

[0037] 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.

[0038] [Granular urea] Granular urea (manufactured by China BlueChemical Limited, particle size: approx. 3mm) [Vegetable hydrogenated oil] Castor hydrogenated oils 1 to 4 and comparative castor hydrogenated oils 1 to 3 were prepared by using commercially available vegetable hydrogenated oils as raw materials and adjusting the melting point, iodine value, and hardness to the following values, respectively. Hardened castor oil 1: Melting point 80-90℃, iodine value 3g I 2 / 100g, hardness 59gf / mm 2 Hardened castor oil 2: Melting point 80-90℃, iodine value 8g I2 / 100g, hardness 39gf / mm 2 Hardened castor oil 3: Melting point 80-90℃, iodine value 14g I 2 / 100g, hardness 27gf / mm 2 Hardened castor oil 4: Melting point 80-90℃, iodine value 20g I 2 / 100g, hardness 24gf / mm 2 Comparative castor oil 1: Melting point 80-90℃, iodine value 37g I 2 / 100g, hardness 7gf / mm 2 Comparative castor oil 2: Melting point 80-90℃, iodine value 48g I 2 / 100g, hardness 2gf / mm 2 Comparative castor oil 3: Melting point 80-90℃, iodine value 59g I 2 / 100g, hardness 0.7gf / mm 2 "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)

[0039] [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 castor hardened oil 1 (210 parts by mass) was added, which was heated and melted at 105°C, and the rolling state was maintained under the heating condition for 3 minutes or more. After that, it was cooled to about room temperature to obtain a coated granular fertilizer (hereinafter, referred to as this coated granular fertilizer 1).

[0040] [Example 2] A coated granular fertilizer was obtained in the same manner as in Example 1, except that hydrogenated castor oil 2 was used instead of hydrogenated castor oil 1 (hereinafter, referred to as this coated granular fertilizer 2).

[0041] [Example 3] A coated granular fertilizer was obtained in the same manner as in Example 1, except that hydrogenated castor oil 3 was used instead of hydrogenated castor oil 1 (hereinafter, referred to as this coated granular fertilizer 3).

[0042] [Example 4] A coated granular fertilizer was obtained in the same manner as in Example 1, except that hydrogenated castor oil 4 was used instead of hydrogenated castor oil 1 (hereinafter, referred to as this coated granular fertilizer 4).

[0043] [Comparative Example 1] A coated granular fertilizer was obtained in the same manner as in Example 1, except that comparative hydrogenated castor oil 1 was used instead of hydrogenated castor oil 1 (hereinafter referred to as comparative coated granular fertilizer 1).

[0044] [Comparative Example 2] A coated granular fertilizer was obtained in the same manner as in Example 1, except that comparative hydrogenated castor oil 2 was used instead of hydrogenated castor oil 1 (hereinafter referred to as comparative coated granular fertilizer 2).

[0045] [Comparative Example 3] A coated granular fertilizer was obtained in the same manner as in Example 1, except that comparative hydrogenated castor oil 3 was used instead of hydrogenated castor oil 1 (hereinafter referred to as comparative coated granular fertilizer 3).

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

[0047] [Comparative Examples 6 to 7] Coated granular fertilizers were obtained in the same manner as in Example 1, 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 6 and 7, respectively).

[0048] [Evaluation of the iodine value of hydrogenated vegetable oil] The iodine values ​​of castor hydrogenated oils 1 to 4 and comparative castor hydrogenated oils 1 to 3 were measured in accordance with "JIS K 0070:1992 Testing methods for acid value, saponification value, ester value, iodine value, hydroxyl value and unsaponifiable matter of chemical products."

[0049] [Evaluation of hardness of hydrogenated vegetable oil] Hardened castor oil 1 was heated to 105°C and melted, poured into a silicone mold, and solidified at room temperature to prepare a particulate test sample with a particle size of about 7 mm. Using a particle hardness measuring device (New Grano, manufactured by Okada Seiko Co., Ltd.), stress was applied to the test sample until cracks were generated. The test sample was judged to have cracked when the stress decreased by 10% during the test or when the test sample was visually confirmed to have broken, whichever came first. The maximum stress (gf) at which the test sample cracked was obtained. The particle size (mm) of the test sample was defined as the displacement of the jig from the bottom surface when the stress first reached 0.06 kgf or more. The maximum stress (gf) and the particle size (mm) were substituted into the following formula 1 to calculate the hardness. The hardness was calculated for 5 or more test samples, and the average value was defined as the hardness. The hardness of castor hydrogenated oils 2 to 4 and comparative castor hydrogenated oils 1 to 3 was also measured in the same manner.

[0050] [Number 1] Hardness = ((2.8 x maximum stress) / (π x grain size) 2 ))

[0051] [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.

[0052] [Table 1]

[0053] [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 4 and the comparative coated granular fertilizers 1 to 3 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.

[0054] [Table 2]

[0055] [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.

[0056] [Table 3]

[0057] [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 21 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. E1 was calculated in the same manner for the present coated granular fertilizers 2 to 3 and the comparative coated granular fertilizer 1. The results are shown in Table 4. (Evaluation Criteria) A: Dissolution rate E1 is less than 15% B: Dissolution rate E1 is 15% or more and less than 30% C: Dissolution rate E1 is 30% or more When the evaluation is A or B, the dissolution controllability can be evaluated as being good.

[0058] [Impact resistance] The coated granular fertilizer 1 was spread using a side stripe fertilizer applicator (Yanmar Co., Ltd., YK6D) and then collected. The collected coated granular fertilizer 1 (2.5 g, 60-80 granules) was placed in a sample bottle, 100 mL of water was added, and the bottle was left to stand at 25°C. After 21 days, the urea concentration was measured using the same method as above. Based on the measured urea concentration, the dissolution rate E2 (%) after mechanical fertilization was calculated. E2 was also calculated in the same manner for coated granular fertilizer 3. Impact resistance was evaluated based on the value of E2 - E1. The results are shown in Table 4. (Evaluation Criteria) A: E2-E1 is less than 20% B: E2-E1 is 20% or more but less than 30% C: E2-E1 is 30% or more When the evaluation is A or B, the impact resistance can be evaluated as good.

[0059] [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 iodine value (gI 2 / 100g) is 35 or less.

2. The hardness of the hydrogenated vegetable oil (gf / mm 2 2. The coated granular fertilizer according to claim 1, wherein the molecular weight of the fertilizer is 10 or more.

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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