Paste fertilizer and method for producing the same

Abstract

The present invention provides a paste fertilizer that exhibits good dispersibility and easy dispersibility (dispersion reproducibility), meaning that even if aggregation occurs, it can be easily broken down. [Solution] A paste fertilizer containing aggregated particles, having a viscosity of 50 to 4000 mPa·s at 23°C, and having an average particle size (D50) of 10 μm or less of the aggregated particles.

Description

Technical Field

[0001] The present invention relates to paste fertilizers and methods for producing the same.

Background Art

[0002] Paste fertilizer is a highly viscous fertilizer mainly used for side-dressing of paddy rice. In paste fertilizer, part of its fertilizer components are not dissolved but dispersed and suspended in the liquid.

[0003] Paste fertilizer is required to have a high viscosity so that the fertilizer components do not diffuse from the fertilization site over a wide range when fertilized. At the same time, it is required that the suspended matter (aggregated particles), which is the fertilizer component, remains stable without separating and settling during long-term storage.

[0004] For example, Patent Document 1 proposes a paste fertilizer characterized by containing at least one of potassium silicate and sodium silicate and modified starch as a paste fertilizer that is chemically and physically stable and does not separate and settle during long-term storage.

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] However, since the paste fertilizer of Patent Document 1 requires the addition of modified starch, there is a concern that the cost will be higher than that of the paste fertilizer using only fertilizer components. In addition, when the viscosity is high, there is a problem that it is difficult to redisperse when aggregation occurs, but Patent Document 1 has not made an effective study on this point.

[0007] Based on the above, the present invention has been made in view of the above, and aims to provide a paste fertilizer that exhibits good dispersibility and easy dispersibility (dispersion reproducibility) that allows for easy dissolution even if aggregation occurs. [Means for solving the problem]

[0008] The inventors of the present invention diligently studied to solve the above problems and found that the present invention can solve these problems, and thus completed the present invention. That is, the present invention is as follows.

[0009] [1] A paste fertilizer containing aggregated particles, having a viscosity of 50 to 4000 mPa·s at 23°C, and having an average particle size (D50) of 10 μm or less of the aggregated particles. [2] The paste fertilizer according to [1], wherein the particle size distribution of the aggregated particles in the range of particle size 1 to 100 μm is unimodal. [3] The paste fertilizer according to [1] or [2], wherein the ratio of the 10% cumulative diameter (D10) to the 90% cumulative diameter (D90) of the aggregated particles (D10 / D90) is 0.1 to 0.5. [4] A paste fertilizer containing biomass fiber, as described in any one of [1] to [3]. [5] The paste fertilizer according to [4], wherein the biomass fiber is at least one of cellulose nanofibers, chitin nanofibers, and chitosan nanofibers. [6] A method for producing paste fertilizer, comprising applying pressure to a fertilizer-containing liquid containing fertilizer components to make it a pressurized fluid, and then applying an impact force to the pressurized fluid. [7] A method for producing paste fertilizer according to [6], wherein the impact force is generated by causing the pressurized fluid to collide with a hard material, or by causing each of the pressurized fluids sprayed from at least one pair of nozzles to collide with each other. [8] A method for producing a paste fertilizer according to [6] or [7], wherein the fertilizer-containing liquid contains biomass fiber. [9] A method for producing paste fertilizer according to any one of [6] to [8], wherein the pressure is 100 to 300 MPa and the number of times the impact force is applied is 1 to 5 times. [Effects of the Invention]

[0010] According to the present invention, it is possible to provide a paste fertilizer that exhibits good dispersibility and easy dispersibility (dispersion reproducibility), meaning that even if aggregation occurs, it can be easily broken down. [Modes for carrying out the invention]

[0011] The paste fertilizer according to one embodiment of the present invention contains aggregated particles, has a viscosity of 50 to 4000 mPa·s at 23°C, and has an average particle size (D50) of 10 μm or less.

[0012] In this embodiment, since the D50 of the aggregated particles is relatively small, at 10 μm or less, it is presumed that the suspension state is easily maintained, resulting in good dispersibility. Furthermore, it is presumed that the moderate viscosity of 50 to 4000 mPa·s prevents the aggregated particles from becoming rigidly aggregated, and even if aggregation occurs, it is easily dispersible (dispersion reproducibility) is achieved.

[0013] Furthermore, smaller aggregated particles tend to result in lower viscosity. Low viscosity means that even when applied to seedlings in a liquid environment such as a paddy field, the fertilizer will disperse away from the seedlings, making it difficult to obtain the desired effect. Therefore, in this invention, by setting the D50 of the aggregated particles to 10 μm or less and the viscosity to 100-4000 mPa·s, a certain degree of viscosity is imparted, making it easier for the fertilizer to remain near the seedlings even when applied to seedlings in a liquid environment, and thus allowing for a sustained effect of the fertilizer.

[0014] From the above perspective, if the viscosity at 23°C is less than 50 mPa·s, it becomes difficult to obtain good dispersion of aggregated particles. If it exceeds 4000 mPa·s, the dispersion reproducibility decreases. The viscosity is preferably between 100 and 2000 mPa·s, and more preferably between 200 and 1000 mPa·s.

[0015] Also, when the average particle diameter (D50) of the aggregated particles according to this embodiment exceeds 10 μm, the good dispersibility of the aggregated particles will deteriorate. The D50 is preferably 1 to 9.7 μm, and more preferably 4 to 9 μm.

[0016] In this embodiment, the particle size distribution of the aggregated particles in the range of particle sizes of 1 to 100 μm is preferably unimodal. By being unimodal, it becomes easier to obtain good dispersion or dispersion reproducibility of the aggregated particles.

[0017] Also, from the viewpoint of its good dispersion or dispersion reproducibility, the 10% cumulative diameter (D10) of the aggregated particles is preferably 1 to 10 μm, and more preferably 3 to 9 μm.

[0018] From the viewpoint of its good dispersion or dispersion reproducibility, the 90% cumulative diameter (D90) of the aggregated particles is preferably 5 to 25 μm, and more preferably 7 to 20 μm.

[0019] In this embodiment, from the viewpoint of good dispersion or dispersion reproducibility of the aggregated particles, the ratio (D10 / D90) of the above D10 to D90 is preferably 0.1 to 0.5, and more preferably 0.3 to 0.4.

[0020] Note that the measurement of D50, D10, and D90, as well as the confirmation of unimodality, can be measured on a volume basis by the method described in the examples.

[0021] The aggregated particles according to this embodiment are fertilizer components that exist in suspension. The fertilizer constituting this fertilizer component is not particularly limited, and may be either a quick-acting fertilizer or a slow-acting fertilizer, more preferably an inorganic fertilizer or an organic fertilizer, and even more preferably a chemical fertilizer.

[0022] For example, components that can be a source of plant nutrients such as inorganic components, silver ions, antioxidants, carbon sources, vitamins, amino acids, and plant hormones can be mentioned as fertilizers.

[0023] Examples of inorganic components include elements such as nitrogen, phosphorus, potassium, sulfur, calcium, magnesium, iron, manganese, zinc, boron, molybdenum, chlorine, iodine, cobalt, etc., and inorganic salts containing any of these elements.

[0024] Examples of inorganic salts include potassium nitrate, ammonium nitrate, ammonium chloride, sodium nitrate, potassium hydrogen phosphate, sodium dihydrogen phosphate, potassium chloride, potassium sulfate, ammonium sulfate, magnesium sulfate, ferrous sulfate, ferric sulfate, manganese sulfate, zinc sulfate, copper sulfate, sodium sulfate, calcium chloride, magnesium chloride, boric acid, molybdenum trioxide, sodium molybdate, potassium iodide, cobalt chloride, etc., and hydrates of any of these.

[0025] Examples of antioxidants include ascorbic acid, sulfites, etc., and ascorbic acid is preferred. Since ascorbic acid has low persistence, environmental pollution can be suppressed.

[0026] Examples of carbon sources include carbohydrates such as sucrose and their derivatives; organic acids such as fatty acids; compounds such as primary alcohols such as ethanol, etc.

[0027] Examples of vitamins include biotin, thiamine (vitamin B1), pyridoxine (vitamin B4), pyridoxal, pyridoxamine, calcium pantothenate, inositol, nicotinic acid, nicotinamide, riboflavin (vitamin B2).

[0028] Examples of amino acids include glycine, alanine, glutamic acid, cysteine, phenylalanine, lysine, etc.

[0029] In addition, the fertilizer components contained in commercially available paste fertilizers may form aggregated particles.

[0030] In this embodiment of the paste fertilizer, it is preferable to further include biomass fibers. Including biomass fibers can improve thickness, dispersion of aggregated particles, and dispersion reproducibility.

[0031] The biomass fibers are preferably biomass nanofibers derived from biomass, such as plant nanofibers and animal nanofibers, and are preferably nano-level fibers with an average diameter (average width) of 1 nm to 1000 nm. It is presumed that these nano-level fibers penetrate between multiple aggregated particles and suppress the aggregation of aggregated particles through steric repulsion, thereby enabling good dispersion of the aggregated particles.

[0032] Examples of biomass nanofibers (BNF) according to this embodiment include cellulose nanofibers, chitin nanofibers, and chitosan nanofibers, from the viewpoint of dispersibility of aggregated particles. Among these, cellulose nanofibers (CNF) are preferred from the viewpoint of chemical stability, thermal stability, and cost.

[0033] The viscosity-average degree of polymerization of biomass nanofibers is preferably 150 to 1000, more preferably 500 to 950, and even more preferably 600 to 900, from the viewpoint of enabling good dispersion and stability of aggregated particles.

[0034] In this case, if the biomass nanofibers are derived from cellulose, it is preferable to calculate the degree of polymerization of the biomass nanofibers by referring to the following paper. TAPPI International Standard;ISO / FDIS 5351,2009.Smith,DK;Bampton, RF;Alexander, WJ Ind. Eng. Chem.,Process Des. Dev.1963, 2, 57-62.

[0035] Specifically, 30 g of a suspension prepared by diluting biomass nanofibers with deionized water to a content of 2 ± 0.3% by mass is placed in a centrifuge tube and left to stand in a freezer overnight to freeze. After further drying in a freeze dryer for more than 5 days, it is heated in a constant-temperature dryer set to 105°C for more than 3 hours but less than 4 hours to obtain completely dry biomass nanofibers.

[0036] To measure the reference, add 15 ml of pure water and 15 ml of 1 mol / L copper ethylenediamine to an empty 50 ml screw-capacity tube to prepare a 0.5 mol / L copper ethylenediamine solution. Place 10 ml of the above 0.5 mol / L copper ethylenediamine solution into a Cannon-Fenske viscometer, let it stand for 5 minutes, and then measure the drop time at 25°C to determine the solvent drop time.

[0037] Next, to measure the viscosity of the biomass nanofibers, weigh between 0.14g and 0.16g of completely dry biomass nanofibers into an empty 50ml screw-capacity tube and add 15ml of pure water. Then, add 15ml of 1mol / L copper ethylenediamine and stir in a rotary-orbit supermixer at 1000rpm for 10 minutes to obtain a 0.5mol / L copper ethylenediamine solution in which the biomass nanofibers have dissolved. Similar to the reference measurement, 10ml of the prepared 0.5mol / L copper ethylenediamine solution is placed in a Cannon-Fenske viscometer, left for 5 minutes, and then the drop time at 25°C is measured. The drop time is measured three times, and the average value is taken as the drop time of the biomass nanofiber solution.

[0038] The degree of polymerization is calculated using the following formula based on the mass of the completely dry biomass nanofibers used in the measurement, the solvent drop time, and the drop time of the biomass nanofiber solution. Note that if the degree of polymerization is measured more than once, the value below is the average of those measurements.

[0039] Mass of the completely dry biomass nanofibers used in the measurement: a (g) (where a is between 0.14 and 0.16) Cellulose concentration in solution: c = a / 30 (g / mL) Solvent settling time: t0 (sec) Falling time of biomass nanofiber solution: t (sec) Relative viscosity of a solution: ηrel = t / t0 Specific viscosity of solution: ηsp = ηrel-1 Intrinsic viscosity: [η]=ηsp / c(1+0.28ηsp) Degree of polymerization: DP=[η] / 0.57

[0040] Furthermore, the viscosity-average degree of polymerization of chitosan nanofibers can be measured by dissolving them in a 2% acetic acid / 0.3M sodium chloride aqueous solution. In the case of chitin nanofibers, the degree of polymerization can be measured by first deacetylating the sample with sodium hydroxide to convert it to chitosan, and then similarly dissolving it in a 2% acetic acid / 0.3M sodium chloride aqueous solution.

[0041] The average fiber diameter of the biomass nanofibers is preferably 3 to 500 nm, more preferably 6 to 100 nm, even more preferably 7 to 50 nm, even more preferably 8 to 25 nm, and most preferably 8 to 15 nm.

[0042] The average length of the biomass nanofibers is preferably such that the aspect ratio (average length / average fiber diameter) is 10 or greater, preferably between 0.5 and 100 μm, and more preferably between 10 and 100 μm.

[0043] The average fiber diameter and length of biomass nanofibers can be calculated from fiber diameter and length (n=20 or so) measured based on electron microscope images taken at appropriate magnification.

[0044] Biomass nanofibers can be produced using various manufacturing methods, including mechanically defibrated biomass nanofibers, and chemically modified biomass nanofibers obtained by chemically treating raw biomass to make it easier to break down, and then mechanically breaking it down.

[0045] Mechanically defibrated biomass nanofibers, compared to those produced by chemical modification, have fewer impurities because they are formed using only the force of a water jet, for example. Furthermore, they exhibit less reduction in the degree of polymerization and crystallinity from the original raw material compared to chemical modification methods. Additionally, they offer advantages such as fewer processing steps, including the elimination of the need for a washing step after chemical modification.

[0046] In the biomass nanofibers according to this embodiment, cellulose nanofibers are preferred, as described above. These cellulose nanofibers can be produced by known methods such as a method of micronizing cellulose fibers used as raw materials, or a method of synthesis using bacteria such as acetic acid bacteria. Examples of micronizing methods include a method using a water jet, a physical treatment using a defibrillator such as a high-pressure homogenizer (mechanical defibrillation), and a chemical treatment (chemical modification) in which cellulose fibers are loosened by an oxidation reaction using enzymes such as cellulase or catalysts. These treatments can be used in combination.

[0047] Examples of raw cellulose fibers include wood pulp such as coniferous pulp and hardwood pulp, cotton pulp such as cotton linters and cotton lint, and non-wood pulp such as wheat straw, rice straw, rice husks, bagasse, bamboo, agricultural residues (vegetable scraps, tea leaves, mandarin orange peels, etc.), herbaceous plants (Miscanthus sinensis, etc.), and seaweed. These can be used individually or in combination of two or more.

[0048] Cellulose nanofibers may be formed by modifying the hydroxyl groups of cellulose in the cellulose molecular chain. Examples of such cellulose nanofibers include those in which the hydroxyl groups of cellulose have been oxidized to carboxyl groups, or those that have been esterified or etherified, or in which other functional groups have been introduced into the cellulose fibers.

[0049] From the viewpoint of effectively exhibiting its dispersion effect, it is preferable to adjust the content of biomass nanofibers in the paste fertilizer so that the viscosity of the paste fertilizer at 23°C is in the range of 50 to 4000 mPa·s.

[0050] In this embodiment, the paste fertilizer is preferably applied together with the seedlings using a dedicated rice transplanter during rice planting. This paste fertilizer can, for example, remain in the root zone of the rice plant, improving its initial growth.

[0051] [Method for manufacturing paste fertilizer] The method for producing paste fertilizer according to this embodiment involves applying pressure to a fertilizer-containing liquid containing fertilizer components to create a pressurized fluid, and then applying a collision force to this pressurized fluid. This method allows for the efficient production of paste fertilizer according to this embodiment.

[0052] The aforementioned impact force is preferably generated by causing the pressurized fluid to collide with a hard material, or by causing the pressurized fluids sprayed from at least one pair of nozzles to collide with each other. This allows for more efficient production of paste fertilizer.

[0053] The fertilizer-containing liquid can be prepared by mixing the fertilizer components described above using a known method. Alternatively, commercially available paste fertilizers may be used. For example, you can use Compound Young Leaf Organic Paste No. 12 from Mitsubishi Agricultural Machinery Co., Ltd., Neo Paste SR502 from Katakura Coop Agri Co., Ltd., Seiwa Paste No. 2 from Seiwa Fertilizer Industry Co., Ltd., High Paste from MC Ferticom Co., Ltd., or any other fertilizer with similar effects. Furthermore, it is preferable that the fertilizer-containing liquid also contains biomass fibers.

[0054] Various methods can be used to impart a dispersive force to a pressurized fluid. For example, it is preferable to use a chamber loaded into a high-pressure injection treatment device that has a configuration to impart a collision force to the pressurized fluid, such as a collision chamber that causes the pressurized fluid to collide with a hard material (e.g., a hard ball), a collision chamber that causes pressurized fluids to collide with each other, or a slit chamber that sterilizes the liquid being treated by compression, shear, turbulence, etc., as it passes through a narrowed-diameter channel (slit).

[0055] Furthermore, a Starburst or similar device manufactured by Sugino Machine Co., Ltd. can be used as the high-pressure injection treatment device. In this case, the pressure is preferably set to 100-300 MPa, and more preferably to 150-300 MPa. The number of times impact force is applied (number of passes) is preferably 1 to 5. By adjusting the pressure and the number of passes, the viscosity at 23°C can be set to 50-4000 mPa·s, and the average particle size (D50) of the aggregated particles can be set to 10 μm or less. In addition, the viscosity of the paste fertilizer can be controlled by adjusting the amount of biomass fiber in the fertilizer-containing liquid. [Examples]

[0056] The present invention will now be specifically described with reference to examples, but the present invention is not limited to these examples.

[0057] [Comparative Example] The particle size, particle size distribution, and viscosity of the aggregated particles of Compound Young Leaf Organic Paste No. 12, manufactured by Mitsubishi Agricultural Machinery Co., Ltd., were measured. Dispersibility and ease of dispersibility were also evaluated. The results are shown in the table below.

[0058] [Examples 1-3] A paste fertilizer was prepared by processing a fertilizer-containing liquid of Compound Young Leaf Organic Paste No. 12 using a Starburst (manufactured by Sugino Machine, device name: HJP-25001, impact chamber using hard balls) under the pressure and number of passes conditions shown in the table below. The particle size, particle size distribution, and viscosity of the agglomerated fertilizer were measured. Dispersibility and ease of dispersibility were also evaluated. The results are shown in the table below.

[0059] [Examples 4-15] A fertilizer-containing solution was prepared by mixing a CNF aqueous dispersion (BiNFi-s series WFo, degree of polymerization of CNF: 650, manufactured by Sugino Machine Co., Ltd.) with Composite Young Leaf Organic Paste No. 12 so that the CNF concentration reached the concentrations shown in Table 1.

[0060] Paste fertilizer was prepared by treating a fertilizer-containing liquid using a Starburst (manufactured by Sugino Machine, device name: HJP-25001, impact chamber using hard balls) under the pressure and number of passes shown in the table below. The particle size, particle size distribution, and viscosity of the paste fertilizer were measured. Dispersibility and ease of dispersibility were also evaluated. The results are shown in the table below.

[0061] • Particle size (D50, D10, D90) and particle size distribution (confirmation of unimodal and multimodal distribution) Measurement and verification were performed using a laser diffraction / scattering particle size distribution analyzer (Partica LA-960 series - HORIBA).

[0062] ·viscosity Measurements were taken at 23°C using a tuning fork vibrating viscometer (SV series, A&D).

[0063] ·Dispersibility Compound Young Leaf Organic Paste No. 12 and the paste fertilizers obtained in Examples 1-15 were each placed in a 50 mL beaker (40 mL each) and left at room temperature (approximately 25°C) for one week. Dispersibility was visually evaluated using the following indicators. A and B are considered acceptable. A: There was no separation or sedimentation of aggregated particles, and good dispersibility was maintained. B: There were more aggregated particles in the lower layer compared to the upper layer, and some separation was observed, but there was no sedimentation. C: Clumps of aggregated particles formed and were settling.

[0064] ·Easy dispersibility (dispersion reproducibility) After evaluating the dispersibility as described above, the mixture was stirred using a glass rod, and the dispersion state was visually assessed using the following indicators. A: It could be easily stirred with a glass rod, and good dispersion was obtained. B: By applying strong force with a glass rod, some degree of stirring was achieved, resulting in good dispersion. C: Although it could be easily stirred with a glass rod, good dispersion could not be achieved.

[0065] [Table 1]

[0066] [Table 2]

Claims

1. A paste fertilizer containing aggregated particles, having a viscosity of 50 to 4000 mPa·s at 23°C, and having an average particle size (D50) of 10 μm or less for the aggregated particles.

2. The paste fertilizer according to claim 1, wherein the particle size distribution of the aggregated particles in the range of particle size 1 to 100 μm is unimodal.

3. The paste fertilizer according to claim 1 or 2, wherein the ratio of the 10% cumulative diameter (D10) to the 90% cumulative diameter (D90) of the aggregated particles (D10 / D90) is 0.1 to 0.

5.

4. A paste fertilizer according to any one of claims 1 to 3, comprising biomass fiber.

5. The paste fertilizer according to claim 4, wherein the biomass fiber is at least one of cellulose nanofibers, chitin nanofibers, and chitosan nanofibers.

6. A method for producing paste fertilizer by applying pressure to a fertilizer-containing liquid that includes fertilizer components to create a pressurized fluid, and then applying a collision force to the pressurized fluid.

7. A method for producing paste fertilizer according to claim 6, wherein the impact force is generated by causing the pressurized fluid to collide with a hard material, or by causing each of the pressurized fluids sprayed from at least one pair of nozzles to collide with each other.

8. The method for producing a paste fertilizer according to claim 6 or 7, wherein the fertilizer-containing liquid contains biomass fiber.

9. A method for producing paste fertilizer according to any one of claims 6 to 8, wherein the pressure is 100 to 300 MPa and the number of times the impact force is applied is 1 to 5 times.

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