JP2014218381A - Antiblocking agent for nitrogen fertilizer, and nitrogen fertilizer composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an antiblocking agent for a nitrogen fertilizer capable of imparting excellent antiblocking properties and moisture absorption-preventing properties to the nitrogen fertilizer, and of maintaining flowability of the nitrogen fertilizer.SOLUTION: An antiblocking agent for a nitrogen fertilizer is characterized by comprising divalent fatty acid metal salt particles obtained by reacting a fatty acid alkali compound salt obtained by reacting an univalent alkali compound with a fatty acid having a carbon number of 8 to 24, with a divalent metal salt in an aqueous solution.

Description

  The present invention relates to an anti-blocking agent for nitrogen fertilizer and a nitrogen fertilizer composition. Specifically, the present invention relates to an anti-blocking agent for nitrogen fertilizer that can improve the blocking resistance and moisture absorption resistance of nitrogen fertilizer and maintain fluidity, and a nitrogen fertilizer composition containing this anti-blocking agent.

Nitrogen fertilizers have the disadvantages of absorbing moisture in the air during storage, causing solidification, impairing fluidity, and significantly reducing workability. For this reason, anti-blocking measures have been studied and many proposals have been made so far, but they have not yet been fully resolved.
For example, in a method in which inorganic powders such as diatomaceous earth, talc, kaolin, and silica powder are dry-mixed with nitrogen fertilizer and coated, these inorganic powders are likely to absorb moisture, so that a sufficient effect cannot be obtained.
Patent Document 1 describes that a fatty acid metal salt is added to and mixed with urea fertilizer and then heated, or granulated after adding the fatty acid metal salt to molten nitrogen. However, in the case of heat treatment, there is a problem that it is difficult to bind nitrogen particles by acting as a binder by softening or dissolving the fatty acid metal salt particles. Further, when granulating by adding to molten nitrogen, the fatty acid metal salt enters into the nitrogen particles, and the surface cannot be coated in an appropriate amount, so that there is a problem that the nitrogen particles are easily blocked.
In addition, the direct method fatty acid metal salts obtained by reacting fatty acids with metal oxides or metal hydroxides are dispersed in nitrogen fertilizer particles because the particle shape is granular and the particle shape is large and irregular. Becomes non-uniform and sufficient covering performance cannot be obtained.

JP 62-235284 A

  The present invention has been made in view of the above-mentioned problems, can impart excellent blocking resistance and moisture absorption resistance to nitrogen fertilizer, and can prevent nitrogen fertilizer from having anti-blocking agent capable of retaining the fluidity of nitrogen fertilizer, and It aims at providing the nitrogen fertilizer composition containing this antiblocking agent.

  As a result of intensive studies to solve the above problems, the present inventor has obtained a divalent fatty acid metal salt particle having 8 to 24 carbon atoms obtained by metathesis, preferably a specific particle size summary value and a specific aggregation degree. The divalent fatty acid metal salt particles having a specific loose bulk density, a specific average circularity C, and powder properties in which a value obtained by dividing the particle size summary value by the average circularity falls within a specific range. The inventors have found that excellent blocking resistance and moisture absorption resistance can be imparted to the nitrogenous fertilizer and that the fluidity of the nitrogenous fertilizer can be maintained, and the present invention has been completed.

  That is, the present invention was obtained by reacting a fatty acid alkali compound salt obtained by reacting a monovalent alkali compound with a fatty acid having 8 to 24 carbon atoms and a divalent metal salt in an aqueous solution. An anti-blocking agent for nitrogen fertilizer (hereinafter, also simply referred to as an anti-blocking agent) characterized by comprising divalent fatty acid metal salt particles.

The antiblocking agent of the present invention has a particle size summary value A represented by the following formula (1) of 2.0 or less, and measured with a powder tester in the fatty acid metal salt particles left for 10 minutes in an environment at 80 ° C. It is preferable that the aggregation degree B (%) represented by the following formula (2) satisfies the relationship of B ≦ 20.
(1) Formula particle size summary value A = (D90−D10) / D50 (where 1.0 ≦ D50 ≦ 40.0)
D10: 10% integrated diameter (μm) of fatty acid metal salt particles based on volume
D50: Median diameter (μm) of fatty acid metal salt particles based on volume
D90: 90% integrated diameter (μm) of fatty acid metal salt particles based on volume

(2) Formula Cohesion B = [(mass of fatty acid metal salt particles remaining on sieve with 350 μm sieve) / 2] × 100 × (1/1) + [(fatty acid metal salt remaining on sieve with 250 μm sieve mesh) Particle Mass) / 2] × 100 × (3/5) + [(Mass of Fatty Acid Metal Salt Particles Remaining on Sieve 150 μm) / 2] × 100 × (1/5)]

  Furthermore, when the antivalent blocking agent of the present invention measures the divalent fatty acid metal salt particles with a flow particle image analyzer, the average circularity C of a particle group having a particle size of 10% to 90% is 0.00. It is preferably 810 to 1.000.

  In the anti-blocking agent of the present invention, the divalent metal constituting the divalent fatty acid metal salt particles is preferably calcium.

  Moreover, this invention contains the anti-blocking agent of this invention, and a nitrogen fertilizer, and the nitrogen fertilizer in which a blocking inhibitor is contained in the ratio of 0.01 mass part-5 mass parts with respect to 100 mass parts of nitrogen fertilizers. It is a composition.

  According to the present invention, it is possible to improve the covering property to nitrogen fertilizer by dry mixing at room temperature, to give the nitrogen fertilizer blocking resistance and moisture absorption prevention, and to maintain fluidity.

  Hereinafter, embodiments of the present invention will be described. The anti-blocking agent for nitrogen fertilizer, nitrogen fertilizer, and nitrogen fertilizer composition of the present invention will be described sequentially.

(1) Anti-blocking agent for nitrogen fertilizer The anti-blocking agent used in the present invention is a fatty acid alkali compound salt obtained by reacting a monovalent alkali compound with a fatty acid having 8 to 24 carbon atoms, and a divalent It consists of divalent fatty acid metal salt particles prepared by a metathesis method in which a metal salt is reacted in an aqueous solution.

  The fatty acid used as the raw material for the fatty acid alkali compound salt is not particularly limited as long as it is a fatty acid having 8 to 24 carbon atoms. That is, any of a naturally occurring fatty acid and a synthetic fatty acid may be used, and either a saturated fatty acid or an unsaturated fatty acid may be used. Preferably, it is a linear saturated fatty acid having 12 to 22 carbon atoms. When the number of carbon atoms is less than 8, it is difficult to obtain an effect as an anti-blocking agent for the obtained fatty acid metal salt particles. On the other hand, fatty acids having more than 24 carbon atoms are difficult to obtain industrially, and the solubility of the resulting fatty acid alkali compound salt in water is significantly reduced, resulting in low productivity.

  Examples of the fatty acid include caprylic acid, capric acid, lauric acid, myristic acid, myristoleic acid, palmitic acid, palmitooleic acid, stearic acid, oleic acid, linoleic acid, arachidic acid, behenic acid, erucic acid and Examples thereof include hydroxystearic acid, among which stearic acid is preferred. When using a mixed fatty acid, a mixed fatty acid having a stearic acid content of preferably 50% by mass or more, more preferably 60% by mass or more, and even more preferably 70% by mass or more is used.

  Examples of the monovalent alkali compound used as the raw material for the fatty acid alkali compound salt include hydroxides of alkali metals (sodium, potassium, etc.) and amines such as ammonia, monoethanolamine, diethanolamine, and triethanolamine. From the viewpoint of high solubility in water when a fatty acid alkali compound salt is used, an alkali metal hydroxide such as sodium or potassium is preferred.

  The fatty acid alkali compound salt used in the present invention generally has a monovalent alkali compound and a fatty acid at a temperature that is not lower than the melting point of the fatty acid and does not decompose the fatty acid, preferably 100 ° C. or lower, more preferably 50 to It is obtained by reacting at 100 ° C., more preferably 60 to 95 ° C., particularly preferably 70 to 95 ° C.

  The divalent fatty acid metal salt particles used in the present invention are fatty acid metal salt particles obtained by reacting the fatty acid alkali compound salt obtained above with a divalent metal salt in an aqueous solution. The divalent metal salt is specifically a salt of a divalent inorganic metal and an inorganic acid or an organic acid. Examples of divalent inorganic metals include alkaline earth metals such as magnesium, calcium and barium, transition metals such as titanium, zinc, iron, manganese, cadmium, mercury, zirconium, lead, copper, cobalt, aluminum and nickel. It is done. Among these, calcium and magnesium are preferable, and calcium is particularly preferable because it is less burdensome on the environment and easily available industrially.

  Examples of the divalent metal salt include calcium chloride, calcium acetate, magnesium chloride, magnesium sulfate, zinc chloride, zinc sulfate, and aluminum sulfate. In particular, chlorides such as calcium and magnesium, sulfates, and nitrates are preferable because they have high solubility in water and efficiently react with fatty acid alkali compound salts.

Specifically, the above reaction is performed by separately preparing a divalent metal salt-containing aqueous solution and a fatty acid alkali compound salt-containing aqueous solution, and then mixing them. For example, the divalent metal salt-containing aqueous solution is added to the fatty acid alkali compound salt-containing aqueous solution, or both are added to another reaction tank.
When mixing the fatty acid alkali compound salt-containing aqueous solution and the divalent metal salt-containing aqueous solution, for example, when the divalent metal salt-containing aqueous solution is added at once to the fatty acid alkali compound salt-containing aqueous solution, the resulting fatty acid metal salt particles There is a possibility that the shape of the material becomes non-uniform and the particle size distribution becomes wide. Therefore, in the present invention, it is preferable that the divalent metal salt-containing aqueous solution is gradually dropped at an appropriate rate with respect to the fatty acid alkali compound salt-containing aqueous solution.

  The concentration of the fatty acid alkali compound salt during the production of the fatty acid metal salt is usually 1% by mass to the productivity of the fatty acid metal salt and the handling property of the fatty acid alkali compound salt-containing aqueous solution or the resulting fatty acid metal salt slurry. 20% by mass, preferably 5% by mass to 15% by mass. When the concentration of the fatty acid alkali compound salt is less than 1% by mass, the productivity of the fatty acid metal salt may decrease, which is not practically preferable. When the amount exceeds 20% by mass, the viscosity of the fatty acid alkali compound salt-containing aqueous solution or the resulting fatty acid metal salt slurry increases, so that it may be difficult to perform a uniform reaction. The concentration of the divalent metal salt in the divalent metal salt-containing liquid is determined from the viewpoint of the productivity of the fatty acid metal salt, and the handling property of the fatty acid alkali compound salt-containing aqueous solution or the obtained fatty acid metal salt slurry. Usually, it is 10 mass%-50 mass%, Preferably it is 10 mass%-40 mass%.

  The reaction between the fatty acid alkali compound salt and the divalent metal salt is performed under temperature conditions that are usually performed by those skilled in the art in consideration of the solubility of the fatty acid alkali compound salt. Preferably it is 50-100 degreeC, More preferably, it is 60-95 degreeC. When reaction temperature is less than 50 degreeC, there exists a possibility that the reaction rate of a fatty-acid alkali compound salt and a bivalent metal salt may fall.

  Polyalkylene glycol ethers, especially oxypropylene blocks, are the oxyethylene blocks for the purpose of stabilizing the fatty acid metal salt slurry during the reaction between the fatty acid alkali compound salt and the divalent metal salt and improving the productivity of the fatty acid metal salt. It is preferable that a triblock ether having a structure sandwiched between (EO-PO-EO) is present in the fatty acid metal salt slurry. The content of the polyalkylene glycol ether in the fatty acid metal salt slurry is usually 0.01 to 5 parts by mass, preferably 0.05 to 2 parts by mass with respect to 100 parts by mass of the fatty acid alkali compound salt. is there. The polyalkylene glycol ether may be present in the reaction system before reacting the monovalent alkali compound with the fatty acid, or the reaction system before the reaction between the fatty acid alkali compound salt and the divalent metal salt. May be present.

  By the above method, a fatty acid metal salt slurry is obtained. This fatty acid metal salt slurry is used as it is or after separating the solvent by a centrifugal dehydrator, filter press, vacuum rotary filter, etc., and if necessary, washing and removing by-product inorganic salts, Drying is performed by an air dryer, an aeration dryer, a spray dryer, a fluidized bed dryer or the like. The drying method may be continuous, batch, normal pressure or vacuum. Furthermore, the dried fatty acid metal salt is pulverized as necessary. The pulverization method is not particularly limited, and for example, a pin mill, a jet mill, an atomizer or the like can be used. The pulverized fatty acid metal salt particles are classified. That is, classification is performed using a multistage sieving apparatus or the like that applies vibrations and performs sieving to adjust the particle size distribution. In this way, fatty acid metal salt particles as an antiblocking agent of the present invention can be obtained.

The fatty acid metal salt particles used in the present invention are divalent fatty acid metal salt particles having 8 to 24 carbon atoms obtained by metathesis, and preferably have a narrow particle size distribution so that the surface of the nitrogen fertilizer On the other hand, it can be made to exist uniformly, and it becomes easy to express the effect (blocking resistance, moisture absorption prevention) of this invention more stably.
Specifically, it is preferable that the particle size summary value A represented by the following formula (1) of the fatty acid metal salt particles is 2.0 or less. In the present invention, the particle size summary value A is calculated from the particle size measured by the microtrack laser diffraction method. When the particle size summary value A exceeds 2.0, due to the variation in the particle diameter of the fatty acid metal salt present on the particle surface of the nitrogenous fertilizer, the coverage with the nitrogenous fertilizer becomes non-uniform, which may cause blocking.

  More preferably, the particle size summary value A satisfies the relationship of 1.0 ≦ A ≦ 1.8. When the relationship of 1.0 ≦ A ≦ 1.8 is satisfied, the effects of the present invention can be obtained more stably. When the particle size summary value A is less than 1.0, it may be difficult to produce industrially, for example, the yield may be significantly reduced.

  The particle size summary value A is adjusted by adjusting the concentration of the fatty acid alkali compound salt, the temperature during the reaction between the fatty acid alkali compound salt and the divalent metal salt, and dropping the divalent metal salt-containing aqueous solution into the fatty acid alkali compound salt-containing aqueous solution. It can carry out by adjusting the dripping speed | rate at the time of carrying out suitably, respectively. In addition, those having a wide particle size distribution, that is, a particle size summary value A having a large value can be obtained by classification using a sieve of 100 mesh, 200 mesh, 330 mesh or the like in post-processing.

  The microtrack laser diffraction method used here is a method for obtaining a particle size distribution using scattered light obtained by irradiating particles with laser light. In the present invention, the measurement is performed by a wet method in which an organic solvent in which the fatty acid metal salt particles are not dissolved, for example, an organic solvent such as ethanol or isopropyl alcohol is circulated, and the sample is directly added. Moreover, the measurement object in this invention is the range of a particle diameter of 0.1 micrometer-200 micrometers, and let the value represented by the following (1) formula be the particle size summary value A. In the present invention, measurement can be performed using, for example, Microtrack MT-3000 manufactured by Nikkiso Co., Ltd.

(1) Formula particle size summary value A = (D90−D10) / D50 (where 1.0 ≦ D50 ≦ 40.0)
D10: 10% integrated diameter (μm) of fatty acid metal salt particles based on volume
D50: Median diameter (μm) of fatty acid metal salt particles based on volume
D90: 90% integrated diameter (μm) of fatty acid metal salt particles based on volume

  According to the study of the present inventors, the aggregation degree B (%) represented by the following formula (2) measured by a powder tester when the fatty acid metal salt particles are left in an environment of 80 ° C. for 10 minutes is B ≦ By satisfying the relationship of 20, the fatty acid metal salt particles can be easily released even under dry mixing conditions with nitrogenous fertilizer, and can be quickly and uniformly dispersed in the nitrogenous fertilizer, so that the blocking resistance and moisture absorption prevention can be improved. .

  The adjustment of the degree of aggregation B is performed by carrying out the reaction between the fatty acid alkali compound salt and the divalent metal salt under mild conditions and preventing aggregation of the fatty acid metal salt particles in the slurry obtained by the reaction. Can do. That is, for example, the reaction can be performed at a mild temperature that does not decrease the reaction rate during the reaction between the fatty acid alkali compound salt and the divalent metal salt, or by shortening the aging time. By appropriately adjusting these factors during the reaction, the degree of aggregation B can be adjusted within the range specified in the present invention.

  The degree of aggregation B (%) is more preferably 2 ≦ B ≦ 18, further preferably 2 ≦ B ≦ 15, and particularly preferably 2 ≦ B ≦ 13. When 2 ≦ B ≦ 13 is satisfied, the operational effects of the present invention can be obtained more stably.

(2) Formula Cohesion B = [(mass of fatty acid metal salt particles remaining on sieve with 350 μm sieve) / 2] × 100 × (1/1) + [(fatty acid metal salt remaining on sieve with 250 μm sieve mesh) Particle Mass) / 2] × 100 × (3/5) + [(Mass of Fatty Acid Metal Salt Particles Remaining on Sieve 150 μm) / 2] × 100 × (1/5)]

The aggregation degree B of the fatty acid metal salt particles by the powder tester used here is a value obtained by the following measuring method. That is, for example, the following steps (a) to (f) are performed using a powder tester (manufactured by Hosokawa Micron Corporation, PT-N type).
(A) The fatty acid metal salt particles to be measured are left for 10 minutes in a thermostat set to 80 ° C.
(B) Sieves of 350 μm, 250 μm, and 150 μm are sequentially set from the upper layer on the vibrating table of the powder tester.
(C) Immediately place 2.0 g of fatty acid metal salt particles after step (a) gently on a sieve having a sieve size of 350 μm.
(D) Vibrate the sieve with an amplitude of 1 mm for 105 seconds.
(E) The mass of the fatty acid metal salt particles remaining on each sieve is measured.
(F) A value obtained by multiplying each mass obtained in the step (e) by a weight of 1/1, 3/5, and 1/5 in order, and adding these to calculate the percentage by the above equation (2). Is a degree of aggregation B (%).
The above steps (a) to (f) are repeated five times, and the average value is taken as the measured value.

  Furthermore, in the fatty acid metal salt particles used in the present invention, the loose bulk density (Da) (g / cc) represented by the following formula (3) is preferably 0.110 ≦ Da ≦ 0.180, More preferably, 135 ≦ Da ≦ 0.160. By being 0.110 ≦ Da ≦ 0.180, when added to nitrogen fertilizer, high slipperiness is obtained in the fatty acid metal salt particles, and high fluidity can be maintained.

  The loose bulk density (Da) is a value obtained by the following measuring method. First, for example, a powder tester (made by Hosokawa Micron Corporation, PT-N type) is used, and a sieve with a mesh size of 710 μm is set on a vibration table, and a sample of 250 cc is placed therein, vibrated for 30 seconds, and placed under the sieve. Collect the dropped sample in the measuring cup. Using the attached blade, scrape excess fatty acid metal salt particles on the cup, and then measure the mass of the cup containing the sample. In the present invention, this operation / measurement is repeated five times, and the average value is taken as the measurement value of the bulk density (Da). In the PT-N type, the measured value is automatically displayed.

(3) Formula Loose bulk density (Da) (g / cc) = mass of cup containing sample (g) / volume of cup (cc)

  The fatty acid metal salt particles used in the present invention are 10% particle diameter to 90% particle diameter when measured by a flow type particle image analyzer from the viewpoint of enhancing the covering property to the granular nitrogen fertilizer when the fatty acid metal salt particles are added. The average circularity C of the particle group is preferably 0.810 to 1.000, more preferably 0.820 to 0.950, and particularly preferably 0.830 to 0.920.

  The average circularity C is adjusted by performing the reaction between the fatty acid alkali compound salt and the divalent metal salt under mild conditions, and the particle shape of the fatty acid metal salt particles in the slurry obtained by the reaction becomes nonuniform. Can be done by preventing. That is, for example, the reaction is performed at a mild temperature that does not reduce the reaction rate during the reaction between the fatty acid alkali compound salt and the divalent metal salt, or the divalent metal salt-containing aqueous solution is changed to the fatty acid alkali compound salt-containing aqueous solution. The dropping can be performed by slowing the dropping speed or adding the above-mentioned polyalkylene glycol ether to stabilize the slurry. By appropriately adjusting these factors during the reaction, the average circularity C can be adjusted within the range specified in the present invention.

  The average circularity in the present invention is used as a simple method for quantitatively expressing the shape of the fatty acid metal salt particles, and can be defined as follows. First, for example, using a flow type particle image analyzer “FPIA-3000” manufactured by Sysmex Corporation, particles within a circle equivalent diameter of 0.5 μm to 200 μm are measured, and the circularity (ai) of each particle measured there. Are obtained by the following equation (4).

Equation (4) Circularity (ai) = (perimeter of a circle having the same area as the projected image of the particle) / (perimeter of the projected particle image)

  Furthermore, for particles in the range of the equivalent circle diameter of 0.5 μm to 200 μm, the value obtained by dividing the total sum of the circularity of all measured particles by the total number of particles (m), as shown by the following equation (5): The average circularity (a) is defined.

  The average circularity in the present invention is an index indicating the degree of unevenness of the particle shape of the fatty acid metal salt. As the surface shape of the fatty acid metal salt particle becomes closer to a circle, it approaches 1.000, and the surface shape of the particle becomes complicated. The average circularity becomes a small value. “FPIA-3000”, which is a measuring apparatus that can be used in the present invention, calculates the circularity of each particle, and classifies the circularity of particles from 0.4 to 1.0 into 61 by the obtained circularity. A calculation method is used in which the average circularity is calculated using the center and frequency of the division points.

  In the present invention, the average circularity C (hereinafter, also simply referred to as “average circularity C”) of a particle group having a particle size of 10% to 90% is a particle size among all particles measured by the measuring device. This is a value obtained by dividing the total circularity of particles in the range of 10% particle diameter to 90% particle diameter from the small particle diameter side of the distribution by the number of particles.

  The average circularity C of a particle group having a particle size of 10% to 90% is measured, for example, as follows. 30 ml of ion-exchanged water from which impure solids and the like have been removed in advance is prepared in a container, and a surfactant, preferably polyoxyethylene-lauryl ether (manufactured by NOF Corporation, trade name: Nonion K-) as a dispersant therein. After adding 204), 20 mg of a measurement sample is further added and dispersed uniformly. As a dispersing means, for example, an ultrasonic dispersing machine UH-50 type (manufactured by SMT Co., 20 kHz, 50 W) equipped with a titanium alloy chip having a diameter of 5 mm as a vibrator is subjected to a dispersion treatment for 5 minutes. The concentration is set to 3,000 / 20,000 to 20,000 / ml to obtain a dispersion for measurement. At that time, the measurement is performed while cooling appropriately so that the temperature of the dispersion liquid for measurement does not become 40 ° C. or higher. Thereafter, measurement is performed using a flow type particle image analyzer “FPIA-3000”, and the average circularity C is obtained by processing the obtained data.

When the present inventors use the obtained fatty acid metal salt particles as an antiblocking agent, among the obtained powder physical properties, the average circularity C of a particle group having a particle size of 10% to 90% and (1 It was found that the numerical relationship with the particle size summary value A in the formula (1) greatly affects the coverage of nitrogen when the fatty acid metal salt particles are added. That is, from the viewpoint of improving the covering property to nitrogen when the fatty acid metal salt particles are added, 0 <(particle size summary value A / average circularity C) ≦ 2.5, and 0 <(particle size summary value A / average circle). Degree C) ≦ 2.3 is preferable, and 0 <(particle size summary value A / average circularity C) ≦ 2.1 is more preferable.
The smaller the value of (particle size summary value A / average circularity C), the narrower and more uniform the particle size distribution of the fatty acid metal salt, and the shape of the individual particles becomes closer to a circle. Nitrogen fertilizer to which high blocking resistance and moisture absorption resistance are imparted can be obtained by quickly and uniformly dispersing and further increasing the covering property to the nitrogen fertilizer particles.

  The anti-blocking agent of the present invention may be used by mixing with a nonionic surfactant. As the nonionic surfactant, an ether type nonionic surfactant is desirable, and polyoxyethylene alkyl ether is more desirable. This is because it is better to use the fatty acid metal salt particles and the nonionic surfactant in combination in the stability of formation of fatty acid metal salt particles in the slurry and the covering property to the granular nitrogen fertilizer by the obtained fatty acid metal salt particles. This is because.

  The antiblocking agent of the present invention is a divalent fatty acid metal salt particle having 8 to 24 carbon atoms obtained by metathesis, and preferably has a specific particle size summary value A, a specific aggregation degree B, as described above. It has a specific loose bulk density and a specific average circularity C, and further has powder physical properties in which a value obtained by dividing the particle size summary value A by the average circularity C falls within a specific range. Such fatty acid metal salt particles can be quickly and uniformly dispersed in nitrogen fertilizer by dry mixing at room temperature, and can be effectively coated on nitrogen fertilizer particles, providing high blocking resistance and moisture absorption prevention. It is preferable in that the fluidity can be maintained.

(2) Nitrogen fertilizer The nitrogen fertilizer in the present invention is a granular material containing a nitrogen fertilizer component. For example, it is a fertilizer containing at least one selected from urea nitrogen fertilizers such as urea, isobutyraldehyde condensed urea and acetaldehyde condensed urea, and ammonia nitrogen fertilizers such as ammonium nitrate, ammonium sulfate, ammonium phosphate and ammonium chloride. The nitrogen fertilizer component can also contain an agrochemical active compound.
The average particle diameter of nitrogen fertilizer is in the range of 0.5 to 5 mm from the viewpoint of production.

(3) Nitrogen fertilizer composition The nitrogen fertilizer composition of the present invention contains the anti-blocking agent of the present invention and the nitrogen fertilizer, and can usually be produced by dry mixing. The dry mixing method is not particularly limited, but in a practical level method, a dry powder mixer such as a V blender or a Henschel mixer can be used.
The nitrogen fertilizer composition of this invention contains the blocking inhibitor of this invention in the ratio of 0.01 mass part-5 mass parts with respect to 100 mass parts of nitrogen fertilizer. If the content of the anti-blocking agent is less than 0.01 parts by mass, it will be difficult to impart certain blocking resistance and moisture absorption prevention to the nitrogen fertilizer. Moreover, if content exceeds 5 mass parts, there exists a possibility that fluidity | liquidity may be impaired by the cohesion of fatty acid metal salt particles.

  Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples.

(Example 1: Preparation of resin-coated sand dispersant)
3L separable flask containing mixed fatty acids (2.1% by weight myristic acid, 30.3% by weight palmitic acid, 66.5% by weight stearic acid, 0.8% by weight arachidic acid, and 0.3% by weight behenic acid) ) 250 g and 2500 g of water were charged, and the temperature was raised to 90 ° C. Subsequently, 77.2 g of 48 mass% sodium hydroxide aqueous solution was added, and it stirred at the same temperature (90 degreeC) for 1 hour, and obtained fatty-acid alkali compound salt aqueous solution. Then, 151.2 g of 35 mass% calcium chloride aqueous solution was dripped at the fatty-acid alkali compound salt aqueous solution over 1 hour, hold | maintaining at 90 degreeC. After completion of dropping, the mixture was further stirred at 90 ° C. for 1 hour. 1500 g of water was added to the obtained mixed fatty acid calcium salt aqueous solution slurry and cooled to 65 ° C. or lower. Thereafter, the mixture was filtered with a suction filter, washed twice with 1000 g of water, and the resulting cake was dried, pulverized and classified with a micron dryer to obtain fatty acid calcium salt particles.

(Example 2)
3L separable flask containing mixed fatty acids (1.6% by weight myristic acid, 24.0% by weight palmitic acid, 73.4% by weight stearic acid, 0.7% by weight arachidic acid, and 0.3% by weight behenic acid) ) 250 g, 0.75 g of polyethylene glycol / polypropylene glycol / block ether (manufactured by NOF Corporation, trade name: Pronon # 104) and 2500 g of water were charged, and the temperature was raised to 90.degree. Subsequently, 76.5 g of 48 mass% sodium hydroxide aqueous solution was added, and it stirred at the same temperature (90 degreeC) for 1 hour, and obtained fatty-acid alkali compound salt aqueous solution. Then, 150.1 g of 35 mass% calcium chloride aqueous solution was dripped at the fatty-acid alkali compound salt aqueous solution over 1 hour, hold | maintaining at 90 degreeC. After completion of dropping, the mixture was further stirred at 90 ° C. for 1 hour. 1500 g of water was added to the obtained mixed fatty acid calcium salt aqueous solution slurry and cooled to 65 ° C. or lower. Thereafter, the mixture was filtered with a suction filter, washed twice with 1000 g of water, and the resulting cake was dried, pulverized and classified with a micron dryer to obtain fatty acid calcium salt particles.

(Comparative Example 1)
10 L pressure kneader contains mixed fatty acids (2.4% by weight myristic acid, 31.1% by weight palmitic acid, 65.4% by weight stearic acid, 0.8% by weight arachidic acid, and 0.3% by weight behenic acid) ) After adding 250 g and heating to 100 ° C., 68.0 g of quicklime was added, the temperature was gradually raised to 140 ° C. while stirring, and the mixture was reacted for 1 hour. The obtained mixed fatty acid calcium salt was dried in a thermostatic bath at 80 ° C. for 3 days, pulverized with a bantam mill, and passed through a 60 mesh sieve to obtain a sample.

  For the fatty acid metal salt particles of Examples 1 and 2 and Comparative Example 1, the particle size summary value A [volume-based 10% cumulative diameter D10 (μm), volume-based median diameter D50 (μm), volume-based 90% cumulative diameter The value calculated from D90 (μm)], the loose bulk density (Da) (g / cc), and the degree of aggregation B (%) were measured by the methods described above using the following apparatuses. The results are shown in Table 1.

(1) Particle size The particle size was measured with a particle size distribution measuring device (device name “Microtrack MT-3000” manufactured by Nikkiso Co., Ltd.). Principle: Laser diffraction / scattering method (2) Loose bulk density Measured with a powder property evaluation apparatus (device name “Powder Tester PT-N type” manufactured by Hosokawa Micron Corporation).
(3) Aggregation degree It measured with the powder characteristic evaluation apparatus (Equipment name "powder tester PT-N type" Hosokawa Micron Corporation make).
(4) Average circularity Measurement was carried out in an aqueous dispersion system using a flow particle image analyzer “FPIA-3000” (manufactured by Sysmex Corporation).

[Production and evaluation of nitrogen fertilizer composition]
Example 1
2 kg of large urea (diameter: 3.0 mm) and 6 g (0.2% by weight) of fatty acid calcium salt particles of No. 1 in Table 1 are charged into a 7 L Henschel mixer, mixed at 30 rpm for 30 minutes at room temperature, and discharged. A nitrogen fertilizer composition was obtained.

(Example 2)
2 kg of large-sized urea (diameter: 3.0 mm) and 6 g (0.2 wt%) of fatty acid calcium salt particles of No. 2 in Table 1 were charged into a 7 L Henschel mixer, mixed at 30 rpm for 30 minutes at room temperature, and discharged. A nitrogen fertilizer composition was obtained.

(Comparative Example 1)
2 kg of large urea (diameter: 3.0 mm) and 6 g (0.2% by weight) of fatty acid calcium salt particles No. 3 in Table 1 were charged into a 7 L Henschel mixer, mixed at 30 rpm for 30 minutes at room temperature, and discharged. A nitrogen fertilizer composition was obtained.

(Blocking test)
200 g of the obtained nitrogen fertilizer composition was put into each of three-layer kraft paper bags (20 cm × 10 cm) each having a vinyl resin layer inside, and the nitrogen fertilizer composition in the bag was flattened to a thickness of about 3 cm. Thereafter, a plate (length × width × thickness = 200 mm × 400 mm × 10 mm; weight 200 g) was placed on the bag. Then, a load of 16 kg was applied, and it was held for 7 days in a constant temperature / humidity chamber maintained at a temperature of 40 ± 2 ° C. and a humidity of 75 ± 5%.
Thereafter, the nitrogen fertilizer composition was taken out from the bag, and the occurrence of blocking (lumps) was observed with the naked eye. The weight of the nitrogen fertilizer composition remaining on the sieve was measured as the amount of blocking generated. The ratio with respect to 100 g of the nitrogen fertilizer composition filled in the bag was determined as a blocking occurrence rate (%), and the formation status of the lump was compared. In addition, the number of lumps was determined with the naked eye.

(Hygroscopic test)
20 g of nitrogen fertilizer composition was put into a weighing bottle (outer diameter × height = 45 mm × 40 mm, capacity of about 34 mL), and held for 7 days in a constant temperature / humidity chamber maintained at a temperature of 30 ± 2 ° C. and a humidity of 65 ± 5%. . Thereafter, the weight of each sample was measured, and the weight increase was compared as the moisture absorption rate (%).

  From the results in Table 2, No. 1 in Table 1 was obtained. 1 and no. The nitrogen fertilizer composition using the fatty acid calcium salt particles of No. 2 is No. 1 in Table 1. Compared to 3, the particle size summary value A is small, the particle size is uniform, the cohesion B is low, the dispersibility is high, and the average circularity is also high, so the covering property against nitrogen fertilizer is high. Can be suppressed. Moreover, it turns out that the high fluidity | liquidity can be provided from the low moisture absorption.

  On the other hand, no. No. 3 has a large particle size summary value A and a non-uniform particle size, and has a low dispersibility. Also, since the average circularity is low, the nitrogen fertilizer has a low covering property, is likely to cause blocking, and has a moisture absorption rate. It became high.

  The anti-blocking agent of the present invention can improve the coverage of nitrogen fertilizer by dry mixing at room temperature, can impart blocking resistance and moisture absorption prevention, and can maintain fluidity.

Claims (5)

  A divalent fatty acid metal salt obtained by reacting a fatty acid alkali compound salt obtained by reacting a monovalent alkali compound with a fatty acid having 8 to 24 carbon atoms and a divalent metal salt in an aqueous solution. An antiblocking agent for nitrogen fertilizer, characterized by comprising particles. In the fatty acid metal salt particles having a particle size summary value A represented by the following formula (1) of 2.0 or less and allowed to stand for 10 minutes in an environment at 80 ° C., the following formula (2) measured by a powder tester The anti-blocking agent for nitrogenous fertilizer according to claim 1, wherein the degree of aggregation B (%) represented satisfies a relationship of B ≦ 20.

(1) Formula particle size summary value A = (D90−D10) / D50 (where 1.0 ≦ D50 ≦ 40.0)
D10: 10% integrated diameter (μm) of fatty acid metal salt particles based on volume
D50: Median diameter (μm) of fatty acid metal salt particles based on volume
D90: 90% integrated diameter (μm) of fatty acid metal salt particles based on volume

(2) Formula Cohesion B = [(mass of fatty acid metal salt particles remaining on sieve with 350 μm sieve) / 2] × 100 × (1/1) + [(fatty acid metal salt remaining on sieve with 250 μm sieve mesh) Particle Mass) / 2] × 100 × (3/5) + [(Mass of Fatty Acid Metal Salt Particles Remaining on Sieve 150 μm) / 2] × 100 × (1/5)]   When the divalent fatty acid metal salt particles are measured by a flow type particle image analyzer, the average circularity C of a particle group having a particle size of 10% to 90% is 0.810 to 1.000. The blocking inhibitor for nitrogen fertilizer according to claim 1 or 2.   The anti-blocking agent for nitrogenous fertilizer according to any one of claims 1 to 3, wherein the divalent metal constituting the divalent fatty acid metal salt particles is calcium.   The anti-blocking agent for nitrogenous fertilizers in any one of Claims 1-4 and a nitrogenous fertilizer are contained, and the anti-blocking agent for nitrogenous fertilizers is 0.01 mass part-5 masses with respect to 100 mass parts of nitrogen fertilizers. A nitrogen fertilizer composition characterized in that it is contained in a proportion of parts.